Institut für Ernährungswissenschaften

Permanent URI for this collection

https://hohpublica.uni-hohenheim.de/handle/123456789/5

Browse

Now showing 1 - 20 of 64

Nutrition and health aspects of mothers and their infants in Bukavu region, Democratic Republic of the Congo : a follow-up study with cross-sectional analyses and nutrition interventions
(2024) Beitze, Damaris Elisabeth; Scherbaum, Veronika
Hintergrund: Mangelernährung in verschiedenen Ausprägungen ist eine Herausforderung für die Bevölkerungsgesundheit in der Demokratischen Republik Kongo, einem Land, das von politischer Instabilität, Gewalt, Nahrungsmittelunsicherheit und Armut geprägt ist. Vor allem verborgener Hunger und Anämie machen einen großen Teil davon aus. Unzureichende Ernährung während der ersten 1000 Lebenstage beeinträchtigt die Gesundheit und Entwicklung eines Kindes kurz- und langfristig. Das Ernährungsverhalten der Mütter spielt sowohl für ihren eigenen Ernährungszustand als auch für den ihrer Kinder eine wichtige Rolle, insbesondere während dieser sensiblen Phase. Der Ernährungszustand und das Ernährungsverhalten können durch vielfältige Faktoren auf verschiedenen Ebenen beeinflusst werden. Diese müssen untersucht und berücksichtigt werden, um zielführende Interventionen zu gestalten. Zielsetzung: Diese Dissertation hatte zum Ziel, den Ernährungsstatus, insbesondere Anämie, stillender Frauen und ihrer Säuglinge zu untersuchen, ebenso wie damit assoziierte Faktoren. Des Weiteren sollte der Einfluss von Ernährungsschulungen und Lipid-basierten Nährstoffsupplementen auf Anämie, Ernährungswissen und Ernährungsverhalten von unter- und übergewichtigen Müttern ermittelt werden. Methoden: Eine Follow-up-Studie mit Querschnittserhebungen und inkludierter Interventionsstudie wurde mit 471 stillenden Müttern und ihren Säuglingen in der Region von Bukavu, Demokratische Republik Kongo von Dezember 2017 bis Juni 2019 durchgeführt. Mutter-Kind-Paare wurden nach der Entbindung in einem von drei Krankenhäusern der Studie (zwei davon semi-urban und eines im ländlichen Gebiet) in der ersten Woche postpartum rekrutiert. Die erste Datenerhebung beinhaltete anthropometrische Messungen der Mütter und Neugeborenen sowie ein strukturiertes Interview zu sozio-demographischen Faktoren und Ernährungsaspekten während der Schwangerschaft. Folgeerhebungen, die 3-6 und 6-9 Monate nach der Geburt stattfanden, umfassten die Messung von anthropometrischen Parametern und der Hämoglobin-Konzentration (Hb) von Müttern und ihren Säuglingen, ein 24-Stunden Ernährungsprotokoll der Mütter sowie ein strukturiertes Interview zu Ernährungswissen und -verhalten. Die randomisierte kontrollierte Interventionsstudie fand zwischen diesen beiden Folgeerhebungen statt. Vor der Intervention wurden die Mütter anhand ihres mittleren Oberarmumfangs (MUAC) in niedrigen (≥ 21 und < 25 cm), normalen (≥ 25 und < 28 cm) und hohen MUAC (≥ 28 cm) eingestuft. Anschließend wurden sie zufällig den folgenden Interventions- und Kontrollgruppen zugeteilt: niedriger MUAC – Ernährungsschulung; niedriger MUAC – Supplement; niedriger MUAC – Kontrolle; mittlerer MUAC – Kontrolle; hoher MUAC – Ernährungsschulung; hoher MUAC – Kontrolle. Über drei Monate erhielten Mütter mit Ernährungsschulungen vier theoretische und zwei praktische Einheiten zu ausgewogener Ernährung, Eisen, Vitamin A und Nährstoffmängeln. Mütter in der Supplement-Gruppe erhielten ein tägliches Lipid-basiertes Nährstoffsupplement. Für 416 Mütter und Säuglinge waren Daten vor und nach der Intervention vorhanden. Ergebnisse: Die Studie zeigte die Koexistenz verschiedener Formen von Mangelernährung in der Studienpopulation. Ernährungs- und Gesundheitsaspekte unterschieden sich zwischen den semiurbanen und ländlichen Gegenden. Das Erhalten von Leistungen während der Schwangerschaftsbetreuung (Malaria-Medikamente, Entwurmung, Supplemente, Ernährungsinformationen durch Gesundheitspersonal) und das Wissen zu sowie die Umsetzung von Familienplanung waren im ländlichen Gebiet geringer als im semi-urbanen Gebiet, ebenso anthropometrische Parameter wie der mütterliche MUAC und das Geburtsgewicht. Eine multiple lineare Regression ergab zunehmenden mütterlichen MUAC, Alter und Gestationsalter als positive Einflussfaktoren auf das Geburtsgewicht, während die ländliche Lage, eine erstgebärende Mutter, eine Tätigkeit der Mutter in der Landwirtschaft und das weibliche Geschlecht des Neugeborenen negative Prädiktoren des Geburtsgewichts waren. Die Anämieraten 3-6 Monate nach der Geburt waren mit 28,2 % bei den Müttern von mittlerer Relevanz für Bevölkerungsgesundheit, lagen bei den Säuglingen mit 74,3 % jedoch im schwerwiegenden Bereich. Sowohl das mütterliche Ernährungswissen als auch ihre Ernährungsvielfalt waren gering ausgeprägt. Im Median hatten die Mütter ein Wissen von 0,39 in einem möglichen Bereich von 0 bis 1 und eine Ernährungsvielfalt von 3,0 (möglicher Bereich 0-10). Ernährungswissen und mütterlicher Hb waren leicht positiv korreliert, aber es bestanden keine signifikanten Korrelationen der Ernährungsvielfalt mit einem dieser beiden Parameter. Geschmack (68,1 %), Aussehen (42,5 %), die Wirkung von Lebensmitteln auf die Gesundheit (29,0 %) und Verfügbarkeit (25,6 %) waren häufige Kriterien der Lebensmittelauswahl. Nach der Intervention hatten Mütter, die Ernährungsschulungen erhalten hatten, ein signifikant höheres Ernährungswissen als diejenigen ohne Schulungen, aber keine verbesserte Ernährungsvielfalt. Außerdem modifizierten mehr Mütter mit Schulungen die Beikost für ihr Kind als die anderen Mütter, häufig im Zusammenhang mit Inhalten der Ernährungsschulungen. Weder der mütterliche Hb nach der Intervention noch die Hb-Entwicklung über die Interventionsphase unterschieden sich signifikant zwischen den sechs Interventions- und Kontrollgruppen. Allerdings war der Anteil an Müttern mit einer Verbesserung des Hb in den Gruppen mit Ernährungsschulungen größer, wenn auch nicht statistisch signifikant. Bei Betrachtung ausschließlich der Frauen, die zu Beginn der Intervention an Anämie litten, zeigte sich eine größere Zunahme des Hb in den Gruppen, die entweder Schulungen oder Supplemente erhielten, allerdings nicht statistisch signifikant. Schlussfolgerungen: Der Ernährungsstatus stillender Frauen und ihrer Säuglinge im Studiengebiet war mangelhaft. Verschiedene Faktoren, die die Mangelernährung befördern könnten, wurden identifiziert: Unzureichende Nahrungsaufnahme und eingeschränkte Leistungen in der primären Gesundheitsversorgung können den Ernährungsstatus beeinflussen. Zu ihren möglichen, vielschichtigen Determinanten gehören geringes Ernährungswissen, die ländliche Gegend und Nahrungsmittelunsicherheit, aber auch persönliche Präferenzen. Um den Ernährungszustand effektiv zu verbessern, müssen Ernährungsinterventionen diese verschiedenen Einflussfaktoren der Nahrungsaufnahme adressieren. Ernährungsschulungen und Lipid-basierte Nährstoffsupplemente könnten einen positiven Effekt haben, vor allem bei Müttern mit Anämie. Sie sollten weiter untersucht werden. Es wird empfohlen, das Bewusstsein und die Qualifikation von Gesundheitspersonal in der primären Gesundheitsversorgung hinsichtlich Ernährung zu stärken und praktische Elemente in Maßnahmen mit Ernährungsschulungen zu integrieren.
Effect of a diet rich in galactose or fructose, with or without fructooligosaccharides, on gut microbiota composition in rats
(2022) Mhd Omar, Nor Adila; Dicksved, Johan; Kruger, Johanita; Zamaratskaia, Galia; Michaëlsson, Karl; Wolk, Alicja; Frank, Jan; Landberg, Rikard
Recent studies suggest that a diet rich in sugars significantly affects the gut microbiota. Adverse metabolic effects of sugars may partly be mediated by alterations of gut microbiota and gut health parameters, but experimental evidence is lacking. Therefore, we investigated the effects of high intake of fructose or galactose, with/without fructooligosaccharides (FOS), on gut microbiota composition in rats and explored the association between gut microbiota and low-grade systemic inflammation. Sprague–Dawley rats (n = 6/group) were fed the following isocaloric diets for 12 weeks (% of the dry weight of the sugars or FOS): (1) starch (control), (2) fructose (50%), (3) galactose (50%), (4) starch+FOS (15%) (FOS control), (5) fructose (50%)+FOS (15%), (6) galactose (50%)+FOS (15%), and (7) starch+olive (negative control). Microbiota composition in the large intestinal content was determined by sequencing amplicons from the 16S rRNA gene; 341F and 805R primers were used to generate amplicons from the V3 and V4 regions. Actinobacteria, Verrucomicrobia, Tenericutes, and Cyanobacteria composition differed between diets. Bifidobacterium was significantly higher in all diet groups where FOS was included. Modest associations between gut microbiota and metabolic factors as well as with gut permeability markers were observed, but no associations between gut microbiota and inflammation markers were observed. We found no coherent effect of galactose or fructose on gut microbiota composition. Added FOS increased Bifidobacterium but did not mitigate potential adverse metabolic effects induced by the sugars. However, gut microbiota composition was associated with several metabolic factors and gut permeability markers which warrant further investigations.
Anemia among Syrian refugee children aged 6 to 23 months living in Greater Beirut, Lebanon, including the Voices of Mothers’ and Local Healthcare Staff: A mixed-methods study
(2023) Jeremias, Theresa; Abou-Rizk, Joana; Burgard, Leonie; Entenmann, Isa; Nasreddine, Lara; Jomaa, Lamis; Hwalla, Nahla; Frank, Jan; Scherbaum, Veronika
Globally, the prevalence of anemia among children during the period of complementary feeding is high. A cross-sectional, mixed-methods study was conducted to examine the main determinants of anemia among Syrian refugee children aged 6 to 23 months (n = 215) and to illuminate the knowledge, attitudes and perceptions of their mothers and Lebanese healthcare staff on its causes and available treatment options. 42% of the children and 20% of their mothers were anemic. Determinants of child anemia were the mother having anemia or not knowing that fish/seafood is a source of iron; the child having been acutely ill the last two weeks or receiving cow’s milk, but not consuming iron-rich infant formula, added fats/oils, or fruits in the previous 24 hours. Several Syrian mothers knew some causes of anemia and named dizziness as a leading symptom but did not mention flesh foods as a key source of heme iron. They reported financial constraints in accessing iron-rich foods and supplements. Lebanese doctors largely gave appropriate dietary advice and prescribed iron supplements as treatment. Multisectoral interventions are needed that combine medical and financial support with nutrition counseling for mothers to reduce the high burden of anemia among young children living in a multiple crises situation.
Optimization of supercritical carbon dioxide extraction of polyphenols from black rosehip and their bioaccessibility using an In Vitro digestion/Caco-2 cell model
(2023) Kasapoğlu, Kadriye Nur; Kruger, Johanita; Barla-Demirkoz, Aslı; Gültekin-Özgüven, Mine; Frank, Jan; Özçelik, Beraat
The fruits of Rosa pimpinellifolia are rich sources of (poly)phenols, however they are underutilized due to the limited information available. The influence of the pressure, temperature, and co-solvent concentration (aqueous ethanol) of the supercritical carbon dioxide extraction (SCO2-aqEtOH) on the extraction yield, total phenolic-, total anthocyanin-, catechin-, cyanidin-3-O-glucoside contents, and total antioxidant activity of black rosehip was investigated simultaneously. The maximum obtained total phenolic and total anthocyanin contents under the optimized extraction conditions (280 bar, 60 °C and 25% ethanol, v/v) were 76.58 ± 4.25 mg gallic acid equivalent and 10.89 ± 1.56 mg cyanidin-3-O-glucoside equivalent per g of the dry fruits, respectively. The optimal extract obtained by SCO2-aqEtOH was compared to two other extraction procedures: ultrasonication using ethanol as solvent (UA-EtOH) and pressurized hot water extraction (PH-H2O). The bioaccessibility and cellular metabolism of the phenolic compounds in the different black rosehip extracts were assessed using an in vitro digestion coupled with a human intestinal Caco-2 cell model. The in vitro digestive stability and cellular uptake of the phenolic compounds had no significant difference among the different extraction methods. The results of this study confirm the efficiency of SCO2-aqEtOH extraction for phenolic compounds and, in particular, for anthocyanins, and could be used to produce new functional food ingredients from black rosehip with high antioxidant power containing both hydrophilic and lipophilic compounds.
Combined effects of drought and soil fertility on the synthesis of vitamins in green leafy vegetables
(2023) Park, Taewan; Fischer, Sahrah; Lambert, Christine; Hilger, Thomas; Jordan, Irmgard; Cadisch, Georg
Green leafy vegetables, such as Vigna unguiculata, Brassica oleraceae, and Solanum scabrum, are important sources of vitamins A, B1, and C. Although vitamin deficiencies considerably affect human health, not much is known about the effects of changing soil and climate conditions on vegetable vitamin concentrations. The effects of high or low soil fertility and three drought intensities (75%, 50%, and 25% pot capacity) on three plant species were analysed (n = 48 pots) in a greenhouse trial. The fresh yield was reduced in all the vegetables as a result of lower soil fertility during a severe drought. The vitamin concentrations increased with increasing drought stress in some species. Regardless, the total vitamin yields showed a net decrease due to the significant biomass loss. Changes in vitamin concentrations as a result of a degrading environment and increasing climate change events are an important factor to be considered for food composition calculations and nutrient balances, particularly due to the consequences on human health, and should therefore be considered in agricultural trials.
Association of Torquetenovirus Viremia with physical frailty and cognitive impairment in three independent European cohorts
(2023) Giacconi, Robertina; Laffon, Blanca; Costa, Solange; Teixeira-Gomes, Armanda; Maggi, Fabrizio; Macera, Lisa; Spezia, Pietro Giorgio; Piacenza, Francesco; Bürkle, Alexander; Moreno-Villanueva, María; Bonassi, Stefano; Valdiglesias, Vanessa; Teixeira, Joao Paulo; Dollé, Martijn E.T.; Rietman, M. Liset; Jansen, Eugène; Grune, Tilman; Gonos, Efstathios S.; Franceschi, Claudio; Capri, Miriam; Weinberger, Birgit; Sikora, Ewa; Stuetz, Wolfgang; Toussaint, Olivier; Debacq-Chainiaux, Florence; Hervonen, Antti; Hurme, Mikko; Slagboom, P. Eline; Schön, Christiane; Bernhardt, Jürgen; Breusing, Nicolle; Pásaro, Eduardo; Maseda, Ana; Lorenzo-López, Laura; Millán-Calenti, José Carlos; Provinciali, Mauro; Malavolta, Marco
Introduction: Immunosenescence and inflammaging have been implicated in the pathophysiology of frailty. Torquetenovirus (TTV), a single-stranded DNA anellovirus, the major component of the human blood virome, shows an increased replication rate with advancing age. An elevated TTV viremia has been associated with an impaired immune function and an increased risk of mortality in the older population. The objective of this study was to analyze the relation between TTV viremia, physical frailty, and cognitive impairment. Methods: TTV viremia was measured in 1,131 nonfrail, 45 physically frail, and 113 cognitively impaired older adults recruited in the MARK-AGE study (overall mean age 64.7 ± 5.9 years), and then the results were checked in two other independent cohorts from Spain and Portugal, including 126 frail, 252 prefrail, and 141 nonfrail individuals (overall mean age: 77.5 ± 8.3 years). Results: TTV viremia ≥4log was associated with physical frailty (OR: 4.69; 95% CI: 2.06–10.67, p < 0.0001) and cognitive impairment (OR: 3.49, 95% CI: 2.14–5.69, p < 0.0001) in the MARK-AGE population. The association between TTV DNA load and frailty status was confirmed in the Spanish cohort, while a slight association with cognitive impairment was observed (OR: 1.33; 95% CI: 1.000–1.773), only in the unadjusted model. No association between TTV load and frailty or cognitive impairment was found in the Portuguese sample, although a negative association between TTV viremia and MMSE score was observed in Spanish and Portuguese females. Conclusions: These findings demonstrate an association between TTV viremia and physical frailty, while the association with cognitive impairment was observed only in the younger population from the MARK-AGE study. Further research is necessary to clarify TTV’s clinical relevance in the onset and progression of frailty and cognitive decline in older individuals.
Demethoxycurcumin and Bisdemethoxycurcumin are more bioavailable than Curcumin: A meta-analysis of randomized cross-over trials in healthy umans and an In Vitro mechanistic exploration
(2023) Desmarchelier, Charles; Sus, Nadine; Marconot, Grégory; Gillet, Guillian; Resseguier, Noémie; Frank, Jan
Background: Curcuminoids are secondary plant metabolites found in turmeric and many dietary supplements. They usually consist of a mixture of curcumin (CUR), demethoxycurcumin (dCUR) and bisdemethoxycurcumin (bdCUR). CUR, the main curcuminoid, has been intensely investigated for its putative effects against, e.g., inflammation, oxidative stress and cancer. However, CUR displays very poor bioavailability. We have previously shown that, when brought by turmeric, dCUR and bdCUR, which can also exert health effects, display greater in vitro bioaccessibility than CUR (PMID: 37073511). However, their bioavailability relative to that of CUR has not been thoroughly investigated. Objective: We aimed to compare the bioavailability of dCUR and bdCUR to that of CUR in a meta-analysis of clinical trials in healthy humans and to compare their in vitro bioaccessibility and enterocyte uptake efficiency. Methods and Results: Studies published until 2022 were searched for using Medline and Scopus. The included studies were randomized trials that measured the bioavailability of CUR, dCUR and bdCUR in healthy participants. Estimates were calculated using a random-effects model. Fifteen trials were included in the study, representing a total of 50 interventions, i.e., each trial investigated several curcuminoid formulations, in 762 participants. The relative bioavailabilities were calculated using the inverse variance method. dCUR was 2.32 (95% CI:1.70, 3.13) times more bioavailable than CUR, while bdCUR was 2.57 (95% CI: 1.58, 4.16) times more bioavailable than CUR, with some heterogeneity across the formulations used. Using an in vitro gastro-intestinal digestion model with pure curcuminoids, we showed that dCUR solubilization efficiency was 4.8 and 5.3 times higher than that of CUR and bdCUR, respectively (p < 0.001), while its micellization efficiency was 10.3 and 5.1 times higher than that of CUR and bdCUR, respectively (p < 0.001). Conclusions: bdCUR and dCUR display greater bioavailability in humans compared to CUR. A subgroup analysis by formulation is undergoing investigation and will be presented. For dCUR, this difference is partly explained by higher in vitro bioaccessibility. Uptake efficiency measurements of pure curcuminoids and of curcuminoids from in vitro digestion fluids are undergoing investigation and will be presented. bdCUR and dCUR might therefore represent relevant alternatives to CUR for the systematic delivery of curcuminoids.
Nutrition-related knowledge, attitudes, practices, and anemia status of lactating mothers in Bukavu, Democratic Republic of the Congo - A cross-sectional analysis
(2024) Beitze, Damaris Elisabeth; Kavira Malengera, Céline; Barhwamire Kabesha, Theophile; Scherbaum, Veronika
Maternal nutrition is impacted by personal and environmental factors including dietary intake, knowledge, food availability, and affordability. This cross-sectional analysis aimed to evaluate nutrition-related knowledge, attitudes, practices, and associations with hemoglobin concentration among lactating mothers in the Bukavu region, Democratic Republic of the Congo. In 444 lactating mothers, nutrition-related knowledge and practice were assessed by questionnaires and translated into knowledge and practice scores ranging from 0 to 1, attitudes and drivers of food choice were assessed, the Dietary Diversity Score (DDS) was assessed with 24 h dietary recalls in a potential range from 0 to 10, and hemoglobin (Hb) was measured in mothers and their infants. Anemia prevalence was 28.2% among mothers and 74.3% among infants aged 3–8 months. Nutritional knowledge and practice were limited (the median total knowledge score was 0.39, median DDS was 3.0). While there were slight positive correlations between knowledge and maternal Hb, DDS did not significantly correlate with either knowledge or Hb. Although half of the mothers stated a perception about their own susceptibility to anemia or vitamin A deficiency (56.4%, 47.4%), less than half of those could justify their estimation (40.9%, 44.2%). Taste (68.1%), appearance (42.5%), availability (29.0%), and health effects (25.6%) were important drivers of food choice. In conclusion, interventions on the different influencing factors including nutrition education strategies are needed.
Dietary intake of fructooligosaccharides protects against metabolic derangements evoked by chronic exposure to fructose or galactose in rats
(2023) Almasri, Fidèle; Collotta, Debora; Aimaretti, Eleonora; Sus, Nadine; Aragno, Manuela; Dal Bello, Federica; Eva, Carola; Mastrocola, Raffaella; Landberg, Rikard; Frank, Jan; Collino, Massimo
Scope: Diets rich in fat and sugars evoke chronic low-grade inflammation, leading to metabolic derangements. This study investigates the impact of fructose and galactose, two commonly consumed simple sugars, on exacerbation of the harmful effects caused by high fat intake. Additionally, the potential efficacy of fructooligosaccharides (FOS), a fermentable dietary fiber, in counteracting these effects is examined. Methods and results: Male Sprague-Dawley rats (six/group) are fed 8 weeks as follows: control 5% fat diet (CNT), 20% fat diet (FAT), FAT+10% FOS diet (FAT+FOS), FAT+25% galactose diet (FAT+GAL), FAT+GAL+10% FOS diet (FAT+GAL+FOS), FAT+25% fructose diet (FAT+FRU), FAT+FRU+10% FOS diet (FAT+FRU+FOS). The dietary manipulations tested do not affect body weight gain, blood glucose, or markers of systemic inflammation whereas significant increases in plasma concentrations of triacylglycerols, cholesterol, aspartate aminotransferase, and alanine aminotrasferase are detected in both FAT+FRU and FAT+GAL compared to CNT. In the liver and skeletal muscle, both sugars induce significant accumulation of lipids and advanced glycation end-products (AGEs). FOS supplementation prevents these impairments. Conclusion: This study extends the understanding of the deleterious effects of a chronic intake of simple sugars and demonstrates the beneficial role of the prebiotic FOS in dampening the sugar-induced metabolic impairments by prevention of lipid and AGEs accumulation.
Stability of bioactive compounds and antioxidant activity in rosehip juice (Rosa spp.)
(2024) Peña, Fabiola; González, Felipe; Jiménez-Aspee, Felipe; Bustamante, Luis; Ruiz, Antonieta
Rosehip fruits, characterized by their high concentrations of bioactive compounds and antioxidant activity (AA), have been traditionally used to make jams, infusions, and juices. Thus, the objective of this research was to evaluate the stability of rosehip juice by determining the concentrations of bioactive compounds and total phenols and the AA using chromatographic and spectroscopic methods. The stability of the juice was evaluated with three treatments and different storage conditions, namely, unpasteurized–refrigerated, pasteurized–room temperature, and pasteurized–refrigerated, and measurements were taken for eight months. Individual and total phenolic compounds, evaluated by chromatographic methods, reported differences until the end of this study. The total phenolic compounds by Folin–Ciocalteu method presented an average decrease of 57% in the three treatments in relation to the initial conditions. On the other hand, the ascorbic acid content decreased considerably, disappearing at week six. Furthermore, for the unpasteurized–refrigerated and pasteurized–refrigerated samples, a correlation was found between flavonols, total phenols, ascorbic acid, and antioxidant activity determined by the TEAC method. For the pasteurized–room temperature samples, correlations were found between the levels of several flavonols, hydroxycinnamic acid, total phenols, and ascorbic acid and the antioxidant activity determined by the CUPRAC method. The stability of the compounds was mainly correlated with the storage conditions of the juice and not with pasteurization. The highest stability was observed for the unpasteurized–refrigerated and pasteurized–refrigerated samples. Although the concentrations of the compounds evaluated decreased during this study, significant levels of AA persisted, providing beneficial characteristics for consumer health.
Entwicklung und Charakterisierung verschiedener humaner 3D Fettgewebemodelle mit und ohne Hydrogelmatrix als in vivo nahe Alternative
(2023) Albrecht, Franziska Brigitte; Kluger, Petra
Humanes Fettgewebe sekretiert hunderte regulatorisch aktive Hormone, die bei der Entstehung und Manifestierung schwerwiegender Krankheiten wie Diabetes oder kardiovaskulären Erkrankungen beteiligt sind. Um die Vorhersagekraft von in vitro Modellen zu verbessern und die Komplexität des nativen Fettgewebes besser nachzubilden, werden dringend dreidimensionale (3D) in vivo nahe Fettgewebemodelle benötigt. Um solch ein flexibel anwendbares möglichst physiologisches Modell aufzubauen wurde in dieser Arbeit der Aufbau und die Evaluierung verschiedener 3D Fettgewebemodelle teils mit artifizieller Matrix angestrebt und im Anschluss mit dem nativen Zustand vergleichen. Beginnend wurden aus primärem humanem Fett Lobuli in verschiedenen Größenbereichen isoliert, kultiviert und der Zelltod sowie Zeichen der Lipolyse bestimmt. Es hat sich gezeigt, dass Lobuli mit einem Gewicht von 27 – 70 mg über 15 Tagen die stabilsten Ergebnisse geliefert haben und wurden somit tiefergehend analysiert. Bei der Analyse der Viabilität und Zellfunktionalität in Form der Lipidakkumulation und der Expression von Perilipin A konnte bewiesen werden, dass Lobuli als Fettgewebemodell genutzt werden können. Als weiteres Modell erfolgte die Etablierung von Sphäroiden aus humanen primären Stammzellen aus dem Fettgewebe (adipose-derived stem cells, ASC). Die Sphäroide wurden für 14 Tage adipogen differenziert und währenddessen die Veränderung des Volumens und der Rundheit sowie die Expression von Zelltodmarkern und das adipogene Differenzierungspotenzial betrachtet. Dabei haben Sphäroide mit mehr als 100.000 Zellen ihr Volumen über die Zeit verkleinert und Apoptose- und Nekrosemarker an den Tagen 0 und 14 gezeigt. Sphäroide bis 100.000 Zellen haben ihr Volumen während der Differenzierung leicht vergrößert und haben die meisten Lipide akkumuliert, Perilipin A und Kollagen Ⅵ exprimiert. Somit konnten ASC-basierte Sphäroide aus 10.000 Zellen, mit signifikanter Lipidzunahme, als weiteres Fettgewebemodell mit hohem Potenzial identifiziert werden. Im Anschluss erfolgte die Etablierung von methacrylierter Gelatine (GelMA) als Biomaterial für die Verkapselung von primären ASCs und reifen Adipozyten (adipocyte, AC) mit anschließendem extrusions-basierten 3D Druck. Es konnte gezeigt werden, dass die homogene Verteilung der lipidgefüllten ACs in eine wässrige Biotintenlösung nur durch schnelles Herunterkühlen auf Eis möglich war. Der anschließende 3D Druck hatte, weder auf die Viabilität noch Funktionalität bzw. adipogene Differenzierung der Zellen signifikante Einflüsse. Die additiv aufgebauten Modelle wiesen an Tag 1 und 8 bzw. 15 in der Lebend-Tot-Färbung keinen vermehrten Zelltod im Vergleich zu den manuellen Modellen auf. Die Färbung der intrazellulären Lipide und Perilipin A sowie die Glycerolfreisetzung als Funktionalitätsmarker, haben dies bestätigt. Im Vergleich zu nativem Gewebe haben differenzierte ASCs (diffASC) nach der Differenzierung signifikant weniger lipidpositive Zellen und freigesetztes Glycerol gezeigt. Auch morphologisch betrachtet, haben ACs in GelMA mehr Ähnlichkeiten zum nativen Gewebe als diffASCs. Aufgrund der begrenzten Langzeitstabilität von GelMA, des Ursprungs und der Vernetzung wurden Biomaterialien ohne tierischen Ursprung evaluiert. Dabei hat sich das niedrig acetylierte Polysaccharid Gellan Gum (GG) als vielversprechendes Material erwiesen. Es konnten stabile und transparente Hydrogele durch die Vernetzung mit divalenten Ionen im Zellkulturmedium aufgebaut werden. Die 1 %-igen Hydrogele waren weder bei indirekter noch direkter Testung zytotoxisch oder haben Monozyten aktiviert. Bestätigt wurde es durch die Laktatdehydrogenase (LDH)-Freisetzung, den Resazurinumsatz und eine Lebend-Tot-Färbung. Azelluläre Gele wurden über 98 Tagen ohne signifikante Veränderungen erhalten und zeigten für Fettgewebe geeignete Materialeigenschaften. Aufgrund dieser Langzeitstabilität konnten diffASCs für 98 Tage in GG kultiviert werden und zu univakuolären Fettzellen reifen. Dies wurde durch die Färbung von intrazellulären Lipiden und Perilipin A sowie der Leptinsekretion und Glycerolfreisetzung bewiesen. Verglichen mit nativem Gewebe wiesen die diffASCs eine vergleichbare, wenn auch kleinere Morphologie, ähnliche Anteile an lipidpositiven und univakuolären Zellen auf. Auf Basis von GG konnten ACs erfolgreich verkapselt und aufgebaut werden. Hierbei erwies sich eine GG Konzentration von 0,5 % als geeignet, da homogen gemischte Hydrogele mit hohem Resazurinumsatz und geringer Glycerolfreisetzung kultiviert werden konnten. Für den additive Aufbau der GG-basierten Modelle, fand eine Optimierung zur Biotinte statt, was durch die initiale Zugabe divalenter Ionen zur Erhöhung der Viskosität und damit Druckbarkeit ermöglicht wurde. Die additiv gefertigten Modelle zeigten keine signifikanten Unterschiede in Bezug auf Viabilität oder Funktionalität. Nach 32 Tagen in Kultur konnten univakuoläre und funktionale Zellen gezeigt werden. Durch die Erhöhung der GG Konzentration auf 1,5 % wurde ein erfolgreiches 6D Bioprintingverfahren etabliert. Auch hier zeigten die in GG verkapselten ASCs keine Viabilitäts-, Morphologie-, oder Differenzierungsunterschiede nach dem Druckprozess. Abschließend erfolgte ein Vergleich der etablierten Modelle wobei die Adipogenese der ASC-basierten Modelle und zum anderen der adipozytenspezifische Phänotyp evaluiert wurde. Hinsichtlich der Viabilität konnten keine Unterschiede festgestellt werden. Das adipogene Differenzierungspotenzial zeigte sich am stärksten im diffASC Hydrogel. Sowohl hier als auch in den Sphäroiden konnten eingelagerte Lipide ohne hormonelle Induktion mit Medium nachgewiesen werden. Die Betrachtung der adipozytenspezifischen Morphologie der ausgereiften Modelle erlaubte den Rückschluss, dass die Zellen in den Monolayern den unausgereiftesten Zustand in Form von multivakuolären, elongierten diffASCs mit Aktin-Stressfasern aufweisen. Die Zellen der anderen Modelle zeigen deutlich größere Lipidvakuolen mit einem abgerundeten Zytoskelett. Die quantitative Bestimmung der Lipid-, Leptin- und Glycerolmenge legt nahe, dass sich die Zellen, außer die im Monolayer, in einem Steady-State befinden, was die relative Genexpression adipozytenspezifischer Gene untermauert. Zusammengefasst wurden in dieser Arbeit sechs unterschiedliche Fettgewebemodelle entwickelt und mit nativem Gewebe verglichen. Jedes Modell weist individuelle Stärken auf, wodurch sich der Anwendungsbereich und die Forschungsfragen unterscheiden. Um ein möglichst in vivo-nahes Modell zu erreichen, sind diffASCs in GG Hydrogelen ein vielversprechendes, langzeitstabiles, ausgereiftes Fettgewebemodell und können daher als flexible Plattform für in vitro Testungen genutzt werden.
Epidemiology and social determinants of chronic diseases attributed adult mortality and its influence on maternal and young child nutrition in Tigray, 2009-2015: evidence from Kilte Awlaelo- Health and Demographic Surveillance Site
(2023) Abera, Semaw Ferede; Scherbaum, Veronika
In Ethiopia, the burden of disease related to communicable diseases has recently decreased significantly, while morbidity and mortality due to non-communicable diseases (NCDs) have increased. At the same, maternal and child malnutrition remained a major public health problem of Ethiopia. In developing countries, where health insurance is largely unavailable, individual medical conditions can also affect the overall and nutritional well-being of household members. In particular, the occurrence of disease and adult mortality in households can affect the nutritional well-being of the most vulnerable household members, especially lactating mothers and their young children. If the diseases are of chronic nature, which usually are costly and adult household members die from it in the long-term, this can be devastating for the family. The aim of this Ph.D. project was to investigate the epidemiology and social determinants of NCDs-attributed adult mortality, and to examine the association of chronic diseases attributed adult mortality with undernutrition of lactating mothers and their young children in rural population of Kilte Awlaelo-Health and Demographic Surveillance Site (KA-HDSS), Eastern Zone of Tigray, Ethiopia. During the data analysis, causes of death in adults were classified into chronic and non-chronic causes. The category of adult mortality due to chronic diseases refers to all causes that may be characterized by a long duration of illness. This group includes all deaths caused by NCDs and chronic communicable diseases such as tuberculosis and HIV/AIDS. The thesis has three articles, all published in peer-reviewed journals. The first article reports findings on the epidemiology and social-determinants of adult mortality caused by NCDs among 45,982 adult residents of KA-HDSS using population-based longitudinal data collected from 2009 to 2015. The second article tested whether the burden of undernutrition was higher among lactating mothers who were living in households with adult mortality from chronic diseases than among lactating mothers living in households with no adult mortality from chronic diseases. The third article examined whether there was an association between undernutrition of children and adult mortality from chronic diseases. Both longitudinal and cross-sectional data were used in the second and third articles. To our knowledge, this study showed for the first time that adult mortality caused by NCDs varied according household members’ relationship to their household head: extended family and non-family members of the household head had higher hazard of mortality compared to the household heads. In addition, this work can be considered as the first study from a low-income setting to examine whether mortality of an adult household member from chronic diseases is associated with undernutrition of lactating mothers and their young children. The results of the first study indicate a double mortality burden from both communicable diseases and NCDs in the study population. Between 2009 and 2015, the leading causes of NCDs-attributed adult mortality were cardiovascular diseases, cancer and renal failure. Compared to heads of households, extended family and non-family co-residents had an increased hazard of mortality from NCDs. Literacy and younger age were protective factors against adult mortality caused by NCDs. However, the protective role of literacy against adult mortality from NCDs decreased with increasing age. Next, we assessed the level of undernutrition among the lactating mothers and examined its association with household-level occurrence of adult mortality from chronic diseases by controlling the effect of a wide range of epi-demographic and agro-ecological variables. Nearly two-fifths (38%; 95% CI: 36.1, 40.1%) of the mothers were undernourished. We found an increased risk of maternal undernutrition for lactating mothers who were living in households which experienced adult mortality from chronic diseases. In addition, maternal undernutrition was strongly associated with recent history of household-level morbidity, poor health-seeking practice, lack of diverse food crops, and a low index score for housing and environmental factors. In the third article, we determined the burden of undernutrition among children of complementary feeding age (6 to 23 months) and its factors within the context of nutrition-specific and -sensitive drivers of young child undernutrition. Here, mortality from chronic diseases were constructed as a nutrition-specific factor. We found high prevalence of wasting (13.7%; 95% CI: 12.1, 15.5%) and inadequate child dietary diversity (81.3%; 95%CI: 79.2, 83.1%). Adult mortality history from chronic diseases was not associated with young child undernutrition and child dietary diversity. However, child undernutrition was strongly associated with recent history of household-level morbidity, maternal undernutrition, low child dietary diversity, poverty, larger family size, insecure employment of household heads, and living in highland areas. Poor household wealth status and lack of diverse food crops production, particularly in highland areas, were also strongly associated with lower child dietary diversity. Overall, this thesis has shown that an epidemiological transition is ongoing in the surveillance population. Population-based intervention measures are recommended that aim to reduce NCD-related adult mortality by targeting the leading causes of death and focusing on vulnerable population subgroups, such as the extended family and nonfamily household members. In this study, there was no association between the occurrence of chronic diseases attributed adult mortality and young child undernutrition. However, adult mortality from chronic diseases was associated with maternal undernutrition. Our findings appear to call for multi-sectoral interventions, mainly by the agriculture, nutrition and health sectors, to promote nutritional well-being of lactating mothers and their dyads in the long-term.
Nutritional and hemoglobin status in relation to dietary micronutrient intake: studies in female and male small-scale farmers from Lindi region, Tanzania, and Gurué district, Mozambique
(2024) Eleraky, Laila; Frank, Jan
Inadequate consumption of micronutrient-dense and protein-rich foods, such as vegetables, legumes and meat, are important contributing causes for malnutrition, anemia and micronutrient deficiencies in rural communities of Tanzania and Mozambique. The increasing public health concern of the malnutrition form of overweight has repeatedly been reported in urban as well as rural areas of Sub-Sahara Africa and may have already reached farmers in Tanzania and Mozambique. Nutritional status is assessed by anthropometry, dietary intake and hemoglobin. Compared to the often-used body mass index (BMI) and traditional 24-hour recall, the mid-upper-arm-circumference (MUAC), as well as a food group-based algorithm (CIMI) can be suitable additional assessment tools, especially in resource poor environments. Cross-sectional studies within the framework of the Vegi-Leg project were conducted to assess the nutritional status (anthropometrics and hemoglobin measurements), and the dietary behaviours (Household Dietary Diversity Scores (HDDS), Food Frequency Questionnaires (FFQ) and 24-hour recalls) of female and male farmers from rural areas of Tanzania and Mozambique. Data were analysed by region, sex, age, partly season (Tanzania)and correlates. Additional data from similar projects, namely Scale-N and Trans-SEC in rural villages of Tanzania were included in MUAC and CIMI analysis. MUAC as an additional and easy-to-handle anthropometric marker for underweight, as well as overweight was evaluated using data from Vegi-Leg and Scale-N surveys. MUAC cut-offs, calculated via BMI cut-offs and multiple linear regression (MLR), compared to those selected by highest Youden’s index (YI) value, were assessed. The CIMI algorithm included 23 food groups and was tested in comparison to NutriSurvey (detailed quantitative 24 hour recalls) with data from Scale-N and Trans-SEC.A total of 1526 farmers from the Vegi-Leg project (669 from Tanzania, 857 from Mozambique) were studied, of whom 19% were overweight and 35% were anemic. The study showed an overall higher prevalence of overweight (19%) than underweight (10%), mainly due to the high prevalence of overweight female farmers (up to 35%) in southern Tanzania. The highest prevalence of overweight and anemia, at 35% and 48%, was observed in Tanzanian and Mozambican women, respectively. Regarding HDDS and FFQ data, pigeon pea farmers in Lindi and Gurué reported high consumption frequencies of cereals, legumes, vegetables and oil, while meat, fish and eggs were only consumed rarely. Overall, only a small proportion of enrolled women and men reached the recommended daily dietary intake of vitamin A (10%), iron (51%) and zinc (44%) according to the 24-hour recalls. Multiple regression models revealed that dark green leafy vegetables (DGLVs) highly predicted vitamin A intake, whereas legumes in Tanzania and starchy plants in Mozambique were the dominant sources of vitamin A. Cereals contributed to over half of the iron and the zinc intake in both countries. Seasonal analysis revealed high fluctuations for the consumption frequency of food items from the food groups ‘legumes and pulses’, ‘green leafy vegetables’, ‘other vegetables’ and ‘fruits’, including tomatoes, pigeon peas, mangoes and oranges. The results from Lindi Tanzania revealed, that in seasons, when the availability of food groups like fruits, legumes or vegetables was low, the consumption frequency decreased significantly. BMI, which correlated positively and strongly with MUAC, was higher in Tanzania than in Mozambique and higher among female than male farmers, and decreased significantly from the age of 65 years. MUAC cut-offs of <24 cm and ≥30.5 cm, calculated by multiple linear regression, detected 55% of farmers being underweight and 74% being overweight, with a specificity of 96%; the higher cut-off <25 cm and lower cut-off ≥29 cm, each selected according to Youden’s Index, consequently detected more underweight (80%) and overweight farmers (91%), but on the basis of a lower specificity (87–88%). The results of the algorithm CIMI and NutriSurvey were similar with regard to the average intake and range of data distribution. The correlation coefficients of NutriSurvey and CIMI with regards to energy (0.931), protein (0.898), iron (0.775) and zinc (0.838) intake, supported the matching of both calculations. An increased consumption of micronutrient rich DGLVs and legumes, while reducing the high amounts of refined sugar, maize and polished rice, is suggested to counteract the high prevalence of anemia and overweight among smallholder farmers in rural Tanzania and Mozambique. MUAC cut-offs to detect malnutrition whether defined via linear regression or Youden’s Index, proved to be easy-to-use tools for large-scale rural screenings of both underweight and overweight. The food group based CIMI algorithm is a valid instrument that calculates energy and nutrient intake in agreement with the preferred nutrition software NutriSurvey.
Food and nutrition security and associated health aspects of Syrian refugee mothers and their offspring : a mixed-method study in Greater Beirut, Lebanon
(2023) Abou-Rizk, Joana; Scherbaum, Veronika
Nutrition during the first 1000 days of life – from conception to two years of age – lays the foundation for optimal health, cognitive and social development, and well-being of children and mothers. Malnutrition and hidden hunger in mothers and their offspring during the perinatal period can have long-lasting and irreversible consequences on human capital and increase the risk to non-communicable diseases among adulthood through intergenerational effects. Since the Arab Spring in 2011, the Syrian humanitarian crisis has escalated to become the world’s largest by the end of 2018, forcing 6.7 million to flee, mainly to neighboring countries. In 2015, Lebanon was the host of more than 1.5 million refugees and displaced persons from Syria, reaching the highest per capita concentration of refugees worldwide. The protracted crisis has increasingly weakened Lebanon, in turn exposing vulnerable groups, especially women of reproductive age and children below five years, to increased risks of inadequate nutrition and health status. To date, there has been a lack of studies among refugees that examine the nutritional and health situation and investigate the underlying and immediate determinants of malnutrition among women of reproductive age and children below five years. Therefore, knowledge gaps regarding the prevalence of anemia and nutritional status of Syrian refugee mothers and children were identified as important research areas in this dissertation. Assessing the food security and mental health of Syrian refugee mothers, examining the dietary intake and infant feeding practices, and investigating their respective determinants and associated risk factors were also important areas of focus. This research project was conducted between July and October 2018 in collaboration with the American University of Beirut in primary healthcare centers in the Greater Beirut area in Lebanon using quantitative and qualitative surveys (mixed-methods survey) among Syrian refugee mothers and their child aged below five years of age. This work comprises a total of three research articles that have been published in peer-reviewed international journals. The first article (Chapter 3) describes the prevalence of anemia and the nutritional status of mothers and children below five years of age and indicates a moderate public heath significance among Syrian refugees in the Greater Beirut area, Lebanon. The existence of the so-called double burden of malnutrition and hidden hunger (micronutrient deficiencies) has been documented, as mothers and children from the same household were affected by undernutrition, overnutrition, and / or anemia. A strong association between maternal and child anemia in the same household and an association between anemia and overweight / obesity among mothers has also been demonstrated. Analysis of the 24-hr dietary recalls of pregnant, lactating, non-pregnant non-lactating mothers revealed inadequate dietary intake and nutrient deficiencies during pregnancy and lactation. The second article (Chapter 4) presents data on the prevalence of food insecurity, low dietary diversity, and poor mental health among Syrian refugee mothers in Greater Beirut, Lebanon. A significant association between food insecurity and low dietary diversity as well as poor mental health status was found. Low household monthly income and a high household crowding index were significantly associated with low dietary diversity and food insecurity. In addition, the results showed that low-income households consumed monotonous diets, characterized by a high consumption of refined starchy staples and grains. The third paper (Chapter 5) focused on the nutritional and health status of infants under six months. Overall, the public heath significance for anemia and wasting was moderate. Inadequate infant feeding practices, such as the intake of pre-lacteal feeding and liquids, were demonstrated in newborns, which in turn contributed to delayed initiation of breastfeeding and low rates of exclusive breastfeeding. Factors supporting infant feeding practices included proper knowledge on maternal nutrition and exclusive breastfeeding and support from healthcare professionals or family during breastfeeding. Identified barriers included cultural practices such as the early introduction of foods, breastmilk substitutes, and giving water or herbal tea to infants under six months of age. Maternal health issues and social factors such as misinformation from family members and violations of the Code of Marketing of Breastmilk Substitutes also affected breastfeeding. A conceptual framework was also developed in this dissertation to provide a comprehensive understanding of the linkages and pathways between the enabling, underlying, and immediate determinants and the nutritional and health outcomes in the context of humanitarian crises. Based on this conceptual framework, three principal pathways were identified to explain the following associations: (1) from the enabling determinants to anemia and nutritional status, (2) from socio-economic status and host country resources to food consumption and diets, and (3) from pre-resettlement experiences and dietary acculturation to food consumption and diets. In addition, the concluding discussion (Chapter 6) presented the role of maternal mental health status and health services and their impact on maternal nutrition and anemia status as well as infant feeding. In summary, this dissertation contributes to the knowledge about the anemia and nutritional status of Syrian refugee women and children as well as on the food security and mental health status of mothers living in an urban setting of a protracted humanitarian crisis in Lebanon. It also provides insights into the emergence of malnutrition among women and children in the context of refugees and shows the pathways between different levels of determinants of nutrition and health. Implications for practice can be drawn from this dissertation, such as the development or strengthening of evidence-based culture-specific nutritional interventions that are targeted to the refugee context. Priorities for future research were also identified, including the need to improve the effectiveness of nutritional interventions in conflict settings.
Toll-like Receptor 9 (TLR9) activation and the innate immune response to microbial and human DNA
(2023) Hsu, Emily; Fricke, Florian W.
The human Toll-like Receptor 9 (TLR9) is an endosomal Pattern Recognition Receptor (PRR) that recognizes DNA sequences containing the unmethylated Cytosine-Guanine (CpG) dimers, which are present in greater abundance in most bacterial genomes compared to those of vertebrates. Specific CpG-containing sequences are strongly stimulatory of human TLR9, as shown in published studies using synthetic oligonucleotides (ODN) and DNA from bacterial species of varying genomic CpG concentration. Human TLR9 activation was experimentally examined in this thesis using DNA extracted from different bacterial sources, human DNA from Caco-2 cells, known immunostimulatory ODN, and short ODN. In vitro assays using fragment length-standardized microbial genomic DNA on HEK-Dual TLR9 Cells and human peripheral blood mononuclear cells (PBMCs) revealed that TLR9 activation strongly correlated to CpG concentration of the input DNA, with an additional influence of CpG-containing 5-mer TCGTT concentration. When DNA of varying origins and fragment lengths were used together, however, complex dynamics of TLR9 activation, co-activation, and repression were observed, which were less predictable than expected from genomic CpG concentration alone. DNase I-treated microbial DNA fragments of less than 15 bp of length were non-activating on their own, but co-activated human TLR9 together with ODN-2006 in Ramos Blue (B) cells. Similarly, human DNA fragments at the length of 50-200 bp co-activated human TLR9 with both ODN-2006 and Escherichia coli DNA in HEK-dual TLR9 cells. In contrast, large human DNA fragments at over 10000 bp of length repressed TLR9 activation by ODN-2006 in Ramos Blue cells. Finally, a preliminary study was conducted in HT-29 cells on the effect of TLR9 activation on the invasion of Fusobacterium nucleatum, an opportunistic gut pathogen with a very low genomic CpG concentration at 0.296%, using ODN-2006 and human DNA as TLR9 activators. While increased presence of intracellular Fusobacterium nucleatum upon treatment with both ODN-2006 and human DNA was noted, more studies are needed to confirm TLR9 activation as a cause of greater bacterial invasion. The human colon is the location of the largest microbial population of the human body, which provides a rich source of non-human DNA in contact with human TLR9 present in intestinal epithelial cells, plasmacytoid dendritic cells (pDCs), and B lymphocytes. Additionally, the daily mass shedding and death of human intestinal epithelial cells provide large amounts of human DNA, which when combined with microbial DNA could result in co-activation and possible autoimmunity. The thesis thus provided an in vitro model of TLR9 activation by complex DNA of varying origins and fragment lengths likely to present in the human gut environment, and prepared a working basis for future studies of TLR9 activation by human fecal metagenomic DNA.
Strain-resolved analysis of the human intestinal microbiota
(2022) Podlesny, Daniel; Fricke, Florian W.
The gut microbiota is ascribed a crucial role in human health, particularly in regulating immune and inflammatory responses, which is why it is being associated with a wide range of diseases, including obesity, diabetes, and cancer. Nonetheless, fundamental ecological questions of microbiome establishment, stability and resilience, as well as its transmission across hosts and generations remain incompletely understood, partly due to the lack of methods for high-resolution microbiome profiling. New insights in this field can therefore directly contribute to the development of bacterial and microbiota-based therapies. This work introduces SameStr, a novel bioinformatic program for strain-resolved metagenomics that allows for the specific tracking of microbes across samples, enabling the detection and quantification of microbial transmission and persistence, as well as the observation of direct strain competition. Deployed across cohorts to process over 4200 metagenomes, SameStr enabled analysis of the microbiome with unprecedented phylogenetic resolution. The data included both publicly available metagenomes and sequence data generated in collaboration with our research partners, and was examined using multivariate statistics and machine learning frameworks. First, the establishment and development of the neonatal microbiota was studied, revealing a birth mode-dependent vertical transmission of the maternal microbiota. The microbiota of neonates born by cesarean section was characterized by increased relative abundance of oxygen-tolerant and atypical organisms and showed signs of a delayed establishment of a strictly anaerobic gut environment in these children. Such birth mode-dependent differences diminished over time, yet were measurable within the first two years of life. Furthermore, strain analysis verified the transmission and colonization of parental microbes, which indicated a possible lifelong colonization by microbes from selected species. The temporal persistence of microbes was also characterized in healthy adults, revealing similar taxonomy-dependent patterns of stability. For some species, persistence has been demonstrated both in children and in adults over a period of at least two years. These species are known for their capability to metabolize host-derived glycans found both in breastmilk and intestinal mucus, pointing to a potential strategy for effective cross-generational microbiota transmission, and warranting additional research to assess the implications of their disturbed transfer for long-term health. Since their specificity allows assignment to individual hosts, fingerprints of individual microbial strains offer the potential to be used in forensics and data quality control applications. Finally, to gain new insights into the microbiota dynamics during Fecal Microbiota Transplantation (FMT), microbial strain transmission was analyzed in the context of a diverse set of patient, microbiome, and clinical conditions. In the analyzed studies, FMT was used for the experimental treatment of a variety of diseases, including colonization with drug-resistant and pathogenic microbes, metabolic and inflammatory bowel diseases, and as an adjunct to the immunotherapeutic treatment of cancer. Analyses uncovered what appear to be the universal drivers of post-FMT microbiota assembly, including clinical and ecological factors that are important for successful transplantation of donor strains. In particular, the relevance of the microbiota dysbiosis of the recipient was emphasized, which was inducible by pre-treating the patient with antibiotics or laxatives. Presumably, this can open up ecological niches in the patients intestines, which favors colonization with donor strains. Colonization rates did not play a role for the treatment success of recurrent C. difficile infections and inflammatory bowel disease, but indicated a trend associated with an improved immune response in cancer patients. Concerningly, the transfer of an atypical and potentially pro-inflammatory microbial community from one donor was also observed, calling for further investigations into the immediate and long-term clinical consequences of FMT. These analyses demonstrate the advantages of a strain-based microbiome analysis. Due to the achieved methodological accuracy, strain-resolved microbial dynamics could be precisely disentangled when comparing longitudinal samples from healthy adults as well as parent-child and patient-donor pairs. This revealed taxonomic, clinical, and ecological factors that are critical to microbiome assembly, including microbial transmission, persistence, and competition. Together, these findings lay the groundwork for future developments of precision personalized microbiota modulation therapies.
Characterization of dietary and genetic influences on the gastrointestinal microbiota
(2023) Bubeck, Alena Marie; Fricke, Florian W.
Although the gut microbiota is known to contribute fundamentally to human health, e.g. by promoting the maturation of the immune system and intestinal homeostasis, the factors shaping its composition are only poorly understood. Extrinsic and intrinsic influences can disturb the tightly controlled equilibrium between the microbiome and the host and induce dysbiosis, which has been linked to diverse health conditions such as obesity, atherosclerotic cardiovascular disease (ACVD) and inflammatory bowel disease (IBD). Therefore, understanding events leading to microbial perturbations and the prediction of associated health outcomes could aid in the prevention and treatment of these conditions. In this work, the impact of dietary and genetic factors on gastrointestinal microbiota compositions were determined, with the diet serving as an exemplary extrinsic, modifiable microbiota-relevant factor and with a genetic deficiency in a mouse model for intestinal inflammation serving as an exemplary intrinsic, non-modifiable microbiota-relevant factor. In both studies, microbial communities obtained from either a human or a murine cohort, respectively, were taxonomically characterized by 16S rRNA gene amplicon sequencing and analyzed in the context of metabolic and inflammatory implications for the host. In ACVD, the reduction of excess blood cholesterol, which is a main risk factor, is tackled by clinical interventions aiming to reduce cholesterol uptake from exogenous, dietary sources or by inhibiting endogenous cholesterol biosynthesis. Cholesterol-to-coprostanol conversion by the intestinal microbiota has also been suggested to reduce intestinal and serum cholesterol availability, but the dependencies of cholesterol conversion on specific bacterial taxa and dietary habits, as well as its association with serum lipid levels remain largely unknown. To study microbiota contributions to human cholesterol metabolism under varying conditions, fecal microbiota and lipid profiles, as well as serum lipid biomarkers, were determined in two independent human cohorts, including individuals with (CARBFUNC study) and without obesity (KETO study) on very low-carbohydrate high-fat diets (LCHF) for three to six months and six weeks, respectively. Across these two geographically independent studies, conserved distributions of cholesterol high and low-converter types were measured. Also, cholesterol conversion was most dominantly linked to the relative abundance of the cholesterol-converting bacterial species Eubacterium coprostanoligenes, which was further increased in low-converters by LCHF diets, shifting them towards a high-conversion state. Lean cholesterol high-converters, which were characterized by adverse serum lipid profiles even before the LCHF diet, responded to the intervention with increased LDL-C, independently of fat, cholesterol and saturated fatty acid intake. These findings identify the cholesterol high-converter type as a potential predictive biomarker for an increased LDL-C response to LCHF diet in metabolically healthy lean individuals. Although the etiology of IBD has not been fully resolved, an interplay between the intestinal microbiota, environmental factors and an individual’s genetic susceptibility is thought to trigger chronic inflammation by a dysregulation of the immune response in the gut. To identify colitis-associated microbiota alterations throughout the development of spontaneous colitis, mice with a genetic deficiency of the anti-inflammatory cytokine Interleukin-10 (IL-10) from different litters were co-housed with wild-type mice and monitored for 20 weeks. The scoring of mice based on their phenotype and stool consistency mirrored the state of mucosal inflammation as assessed based on histopathological examinations and cytokine expression profiles. Also, the state of colitis was characterized by global microbiota alterations and susceptibility to colitis was dependent on litter-specific microbiome compositions that mice adopted early on in their lives. Colitis development was further associated with the presence of the bacterial genus Akkermansia in mature mice shortly before symptoms manifested. This genus was also a good predictor of colitis-related mice withdrawal, suggesting the potential of Akkermansia to serve as an early onset, subclinical colitis marker. In summary, fecal microbiota characterizations in response to LCHF diets in humans and throughout the development of intestinal inflammation in a colitis mouse model highlight the potential of personalized microbiome-based patient classifications to predict clinical outcomes and improve treatment approaches.
Identification and quantification of tocomonoenol isomers in plants and microalgae and investigation of their metabolism in liver cells
(2022) Montoya Arroyo, Alexander; Frank, Jan
Tocopherols (T), tocomonoenols (T1), and tocotrienols (T3) are tocochromanols, a group of bioactive compounds composed of a chromanol ring and a 16-carbon sidechain with biological functions, such as the protection of lipid membranes from oxidation and the modulation of cellular signaling. T have saturated sidechains, while T1 and T3 have a single or three double bonds in theirs, respectively. The prefixes alpha-, beta-, gamma-, and delta- are assigned based on the number and positions of methyl groups on the chromanol ring. alpha-, beta-, gamma-, and delta-congeners of T1 have been reported, with alpha-T1 being the predominantly identified congener. Two different alpha-T1 isomers are known, 11-alpha-T1, which has been mainly found in land plants, and 12-alpha-T1, which has been mostly detected in marine organisms. However, little is known regarding the occurrence of T1 in photosynthetic organisms and their metabolism in the liver, a strong determinant of bioavailability and bioactivity. The aim of this thesis was to evaluate underutilized plant-based food sources, cyanobacteria, and microalgae as potential sources of T1 and to characterize the uptake and conversion into metabolites of T1 in cultured liver cells in comparison to T and T3. Acrocomia aculeata fruits were analyzed for alpha-T1 due to its phylogenetic relationship with Elaeis spp, the most common source of this congener. No alpha-T1 was detected in oils from endosperm and mesocarp of wild fruits of Acrocomia aculeata from Costa Rica. Aerial parts of the local underutilized leafy vegetable Urtica leptophylla were evaluated as source of T1 due to its agronomical potential and previous reports of T1 in leaves of plants. LC-MS analyses indicated that leaves and flowers of Costa Rican Urtica leptophylla contain minor amounts of alpha-T1 and gamma-T1. Cyanobacteria and microalgae from different species and origins were analyzed as source of alpha-T1 due to their role as primary producers in aquatic ecosystems and the reported presence of 12-alpha-T1 in marine phytoplankton. alpha-T1 in cyanobacteria and microalgae ranged from traces up to 17% of the total tocochromanol content. alpha-T1 concentrations alone were higher than the sum of all four T3. 11-alpha-T1 was the major alpha-T1 isomer in cyanobacteria and microalgae, as determined by GC-MS. Hence, 11-alpha-T1 is a product of biosynthetic pathways even in aquatic organisms. The effect of nitrogen depletion during the cultivation of microalgae on their alpha-T1 content was investigated. Nitrogen depletion did neither significantly affect the relative or absolute content of alpha-T1, despite an increase in tocochromanol content, nor the proportion of 11-alpha-T1/12-alpha-T1 in microalgae. The uptake and conversion into metabolites of 11-alpha-T1 in HepG2 liver cells was compared to those of alpha-T3 and alpha-T. Cellular uptake of alpha-T1 in liver cells was higher than that of alpha-T. 11-alpha-T1, similar to alpha-T, was converted mostly to alpha-carboxymethylhydroxychroman in a time dependent manner, but to lower extend than alpha-T3. The effect of both ring methylation and sidechain saturation on the uptake and metabolism of the alpha- and gamma-congeners of T1, T and T3 was studied in HepG2 cells. gamma-Congeners were metabolized at higher extent than alpha-congeners and metabolite production increased with increasing number of double bonds in the sidechain independently of chromanol ring methylation. In conclusion, alpha-T1 is present with up to 17% of total tocochromanols in cultured microalgae, which thus are an important new source of this congener. gamma-T1 is only a minor tocochromanol in U. leptophylla flowers. 11-alpha-T1, and not 12-alpha-T1, is the major alpha-T1 isomer in cyanobacteria and microalgae and nitrogen depletion of microalgae does not significantly affect alpha-T1 concentration. The metabolic conversion of alpha-T1 into alpha-carboxymethylhydroxychroman in HepG2 cells is similar to that of alpha-T and significantly lower than that of alpha-T3, suggesting that it may be handled by the organism similar to alpha-T. In conclusion, novel potential food sources of alpha-T1 have been identified and, because of similarities with alpha-T, its pharmacokinetics and biological activities warrant further investigation.
Maternal psychosocial stressors, depression and its implications on maternal and infant nutrition : a longitudinal birth cohort study in South West Ethiopia
(2022) Woldetensay, Yitbarek Kidane; Scherbaum, Veronika
This thesis draws on theoretical background and a conceptual model of how selected psychosocial stressors (household food insecurity and intimate partner violence) and coping strategies (maternal social support) are linked to psychological distress (maternal depression) which can influence the nutritional status of mothers and infants. The scientific contribution of this work is threefold. First, it adds to the existing literature on the links between psychosocial stressors, social support and depression, by showing the degree to which household food insecurity and intimate partner violence during pregnancy are associated with the risk of antenatal depressive symptoms, and whether maternal social support plays a buffering role in this process. Second, it describes the longitudinal relationship of prenatal and postnatal depressive symptoms with infant feeding practices. Finally, this work contributes to the literature on depression by validating one of the most commonly applied depression measurement tools, the patient health questionnaire (PHQ-9), in a new culture and language. This thesis includes three research articles; two were published in peer-reviewed journals and the third manuscript is currently under peer review. The first article is a validation study of the depressive symptoms measurement tool in a new culture and language in a rural setting. The other two papers are based on ENGINE birth cohort data, a prospective community-based birth cohort study conducted by Tufts University in collaboration with Jimma and Hawassa Universities and the Ethiopian Public Health Institute in the southwest part of Ethiopia. The first article validated an Afaan Oromo language version of the Patient Health Questionnaire (PHQ-9). PHQ-9 is one of the most commonly used depressive symptoms measurement scales. Few validation studies have been conducted in sub-Saharan Africa for scales seeking to detect depression in pregnant women and to the author’s knowledge this is the first validation of the PHQ-9 in this language. The main finding of the first paper was that the PHQ-9 scale has acceptable reliability and validity as a screening instrument for depressive symptoms among Afaan Oromo speaking Ethiopian pregnant women. The PHQ-9 score of eight or above was found to be an optimal cut-off point to diagnose prenatal depressive symptoms with a sensitivity and specificity of 80.8% and 79.5% respectively. The second article tested hypotheses derived from Lazarus and Folkman’s stress and coping theory. This theory provides a basis for understanding the impacts of psychosocial stressors on the development and prognosis of depression and the buffering effect of coping mechanisms. The hypotheses are as follows: increased psychosocial stressors, specifically intimate partner violence and household food insecurity during pregnancy, lead to higher prenatal depressive symptoms, and strong social support from friends,families and partners have a buffering effect. The present results supported these hypotheses by demonstrating that both household food insecurity and intimate partner violence were positively associated with prenatal depressive symptoms. Simultaneously, strong social support from friends, families and partners was negatively associated with prenatal depressive symptoms. The second article tested another hypothesis that the risk of prenatal depression is higher in anemic pregnant women. The current study supported this hypothesis by demonstrating that anemic pregnant women experienced a higher risk of prenatal depressive symptoms than their non-anemic counterparts. The second paper also investigated the degree to which socio-demographic factors such as age, marital status, educational status, and family size predicted the risk for prenatal depression among pregnant women. The results suggested that unmarried pregnant women and women living in households with large family size were at higher risk of prenatal depressive symptoms. The third paper tested one hypothesis that infants born to mothers with maternal depressive symptoms (prenatal and postnatal) are more likely to have poor infant feeding practices than their counterparts. The present study findings supported this hypothesis by showing that immediate postnatal depressive symptoms are negatively associated with infant feeding practices. However, there was no association between prenatal depressive symptoms and infant feeding practices. The results also showed that intimate partner violence was negatively associated with infant feeding practices. In this study, strong maternal social support and active social participation were positive predictors of infant feeding practices. Contrary to expectations, the present study also found that household food insecurity and infant morbidity episodes were positively associated with infant feeding practices. Finally, the third article’s findings suggested that maternal educational status was positively associated with infant feeding practices and preterm babies were at higher risk of poor infant feeding practices. Infant gender did not affect infant feeding practices in this study. Overall, this PhD thesis provided support for Lazarus and Folkman’s stress and coping theory by demonstrating that psychosocial stressors were positively associated with prenatal depressive symptoms and perceived maternal social support was negatively associated with prenatal depressive symptoms. The thesis also found that anemia during pregnancy is a predictor of prenatal depressive symptoms. Additionally, early postnatal depression and intimate partner violence negatively affect infant feeding practices, whereas perceived maternal social support and active social participation predict appropriate infant feeding practices. The study has a number of implications for practice and future research including prioritization of early screening for maternal depressive symptoms and intimate partnerviolence, and promotion of social support and active social participation as a means of preventing maternal depression and improving maternal and infant nutritional status.
The influence of phosphate-availability and phytic acid on the profiles of fatty acids, (poly)phenols, carotenoids, and tocochromanols in maize (Zea mays L.) grains – from field experiments to human in vitro digestion studies
(2022) Lux, Peter Erwin; Frank, Jan
Phosphorus (P) is an essential element for living organisms and involved in phosphorylation reactions, including the biosynthesis of several organic micronutrients. Since P is taken up by plants from soil as phosphates, phosphate fertilizers are applied on fields to support the P-supply for crops. Today, shrinking global P-resources demand a reduction in the application of P-containing fertilizers, but knowledge about possible effects of a reduced phosphate-availability in soils on the quality of maize grains is lacking. Thus, it was hypothesized that a reduced phosphate-availability in soil influences the concentrations of dietary organic compounds (phenolics, fatty acids, carotenoids, and tocochromanols) in grains of maize during cultivation. Moreover, concentration differences in the P-storage form phytic acid in maize grains may impact the oxidative stability of these organic compounds during processing and digestion. Fertilizer experiments with maize hybrids were conducted at study sites with low to high phosphate concentrations in soil (1.6 to 20.6 mg CAL-P/100 g soil) in Germany. GC-MS or HPLC-(MS) analyses of the ground maize grains revealed the identity of fatty acids, insoluble (mostly diferulic and triferulic acids) and soluble (poly)phenols, carotenoids, and tocochromanols. The concentrations of these (poly)phenols, carotenoids, and tocochromanols as well as the fatty acid composition in the grains of the maize plants grown with or without phosphate fertilizer were not significantly (p < 0.05) different. Interaction effects between phosphate application and the locations on the fatty acid composition as well as on carotenoids and tocochromanols were considered as insignificant, concluding that a reduction in phosphate fertilization could be implemented on most fields in Germany when only considering these dietary compounds. Lastly, the influence of phytic acid on oxidation processes in maize during processing of porridge and in vitro digestion was examined. Porridges were prepared from maize flour containing either high phytic acid concentration or low phytic acid concentration supplemented with or without phytate. The porridges were digested using a human in vitro digestion model, resulting in a decrease in tocochromanols, carotenoids and unsaturated fatty acids. Oxidation products (alpha-tocopherylquinone, malondialdehyde) were formed in all samples, implying that phytic acid addition did not show the expected protective effect. The addition of phytate evoked a significant reduction in the micellarization efficiency of most carotenoids. Thus, the knowledge about phytic acid as antinutrient was extended.

Browse

Recent Submissions