Fecal transplant from vaginally seeded infants decreases intraabdominal adiposity in mice.

Exposing C-section infants to the maternal vaginal microbiome, coined "vaginal seeding", partially restores microbial colonization. However, whether vaginal seeding decreases metabolic disease risk is unknown. Therefore, we assessed the effect of vaginal seeding of human infants on adiposity in a murine model. Germ-free mice were colonized with transitional stool from human infants who received vaginal seeding or control (placebo) seeding in a double-blind randomized trial. There was a reduction in intraabdominal adipose tissue (IAAT) volume in male mice that received stool from vaginally seeded infants compared to control infants. Higher levels of isoleucine and lower levels of nucleic acid metabolites were observed in controls and correlated with increased IAAT. This suggests that early changes in the gut microbiome and metabolome caused by vaginal seeding have a positive impact on metabolic health.

Associations of Fecal Microbiota with Ectopic Fat in African Caribbean Men.

OBJECTIVE: The gut microbiome has been associated with visceral fat (VAT) in European and Asian populations; however, associations with VAT and with ectopic fats among African-ancestry individuals are not known. Our objective was to investigate cross-sectional associations of fecal microbiota diversity and composition with VAT and ectopic fat, as well as body mass index (BMI), among middle-aged and older African Caribbean men. METHODS: We included in our analysis n = 193 men (mean age = 62.2 ± 7.6 years; mean BMI = 28.3 ± 4.9 kg/m2) from the Tobago Health Study. We assessed fecal microbiota using V4 16s rRNA gene sequencing. We evaluated multivariable-adjusted associations of microbiota features (alpha diversity, beta diversity, microbiota differential abundance) with BMI and with computed tomography-measured VAT and ectopic fats (pericardial and intermuscular fat; muscle and liver attenuation). RESULTS: Lower alpha diversity was associated with higher VAT and BMI, and somewhat with higher pericardial and liver fat. VAT, BMI, and pericardial fat each explained similar levels of variance in beta diversity. Gram-negative Prevotellaceae and Negativicutes microbiota showed positive associations, while gram-positive Ruminococcaceae microbiota showed inverse associations, with ectopic fats. CONCLUSIONS: Fecal microbiota features associated with measures of general adiposity also extend to metabolically pernicious VAT and ectopic fat accumulation in older African-ancestry men.

Plant-based diets and the gut microbiome: findings from the Baltimore Longitudinal Study of Aging.

BACKGROUND: Mounting evidence indicates that although some plant-based diets are healthful, others are not. Changes in the gut microbiome and microbiome-dependent metabolites, such as trimethylamine N-oxide (TMAO), may explain differential health effects of plant-based diets. However, human data are sparse on whether qualitatively distinct types of plant-based diets differentially affect gut microbiome diversity, composition, particularly at the species level, and/or metabolites. OBJECTIVES: We aimed to examine cross-sectional associations of different plant-based indices with adult gut microbiome diversity, composition, and the metabolite TMAO. METHODS: We studied 705 adults in the Baltimore Longitudinal Study of Aging with data for diet, fecal microbiome (shotgun metagenomic sequencing), and key covariates. We derived healthful plant-based diet index (hPDI) and unhealthful plant-based diet index (uPDI) using data from food frequency questionnaires. We examined plant-based diet indices with microbiome α-diversity (richness and evenness measures), ß-diversity (Bray-Curtis and UniFrac measures), composition (species level), and plasma TMAO. We used regression models to determine associations before and after adjustment for age, sex, education, physical activity, smoking status, body mass index, and total energy intake. RESULTS: The analytic sample (mean age, 71.0 years, SD = 12.8 years) comprised 55.6% female and 67.5% non-Hispanic White participants. hPDI was positively and uPDI negatively associated with microbiome α-diversity, driven by microbial evenness (Pielou P < 0.05). hPDI was also positively associated with relative abundance of 3 polysaccharide-degrading bacterial species (Faecalibacterium prausnitzii, Eubacterium eligens, and Bacteroides thetaiotaomicron) and inversely associated with 6 species (Blautia hydrogenotrophica, Doreasp CAG 317, Eisenbergiella massiliensis, Sellimonas intestinalis, Blautia wexlerae, and Alistipes shahii). Furthermore, hPDI was inversely associated with TMAO. Associations did not differ by age, sex, or race. CONCLUSIONS: Greater adherence to a healthful plant-based diet is associated with microbiome features that have been linked to positive health; adherence to an unhealthful plant-based diet has opposing or null associations with these features.

Associations of Plastic Bottle Exposure with Infant Growth, Fecal Microbiota, and Short-Chain Fatty Acids.

BACKGROUND/OBJECTIVES: Murine models show that plastics, via their chemical constituents (e.g., phthalates), influence microbiota, metabolism, and growth. However, research on plastics in humans is lacking. Here, we examine how the frequency of plastic bottle exposure is associated with fecal microbiota, short-chain fatty acids (SCFAs), and anthropometry in the first year of life. SUBJECTS/METHODS: In 442 infants from the prospective Nurture birth cohort, we examined the association of frequency of plastic bottle feeding at 3 months with anthropometric outcomes (skinfolds, length-for-age, and weight-for-length) at 12 months of age and growth trajectories between 3 and 12 months. Furthermore, in a subset of infants (n = 70) that contributed fecal samples at 3 months and 12 months of age, we examined plastic bottle frequency in relation to fecal microbiota composition and diversity (measured by 16S rRNA gene sequencing of V4 region), and fecal SCFA concentrations (quantified using gas chromatography mass spectrometry). RESULTS: At 3 months, 67.6% of infants were plastic bottle fed at every feeding, 15.4% were exclusively breast milk fed, and 48.9% were exclusively formula fed. After adjustment for potential confounders, infants who were plastic bottle fed less than every feeding compared to those who were plastic bottle fed at every feeding at 3 months did not show differences in anthropometry over the first 12 months of life, save for lower length-for-age z-score at 12 months (adjusted ß = -0.45, 95% CI: -0.76, -0.13). Infants who were plastic bottle fed less than every feeding versus every feeding had lower fecal microbiota alpha diversity at 3 months (mean difference for Shannon index: -0.59, 95% CI: -0.99, -0.20) and lower isovaleric acid concentration at 3 months (mean difference: -2.12 µmol/g, 95% CI: -3.64, -0.60), but these results were attenuated following adjustment for infant diet. Plastic bottle frequency was not strongly associated with microbiota diversity or SCFAs at 12 months after multivariable adjustment. Frequency of plastic bottle use was associated with differential abundance of some bacterial taxa, however, significance was not consistent between statistical approaches. CONCLUSIONS: Plastic bottle frequency at 3 months was not strongly associated with measures of adiposity or growth (save for length-for-age) over the first year of life, and while plastic bottle use was associated with some features of fecal microbiota and SCFAs in the first year, these findings were attenuated in multivariable models with infant diet. Future research is needed to assess health effects of exposure to other plastic-based products and objective measures of microplastics and plastic constituents like phthalates.

The gut microbiome and regional fat distribution: Findings from the Baltimore Longitudinal Study of Aging.

OBJECTIVE: The aim of this study was to examine associations of gut microbiome diversity and composition with directly measured regional fat distribution, including central fat, in a large community-based cohort. METHODS: A cross-sectional investigation was conducted in the Baltimore Longitudinal Study of Aging (N = 815, 55.2% female, 65.9% White). The fecal microbiome was assessed using whole-genome shotgun metagenomic sequencing, and trunk and leg fat was measured using dual x-ray absorptiometry. Multivariable-adjusted associations of regional fat measures, BMI, or waist circumference with microbiome alpha diversity metrics, microbiome beta diversity metrics, and species differential abundance (verified using two compositional statistical approaches) were examined. RESULTS: Trunk fat, leg fat, BMI, and waist circumference all significantly explained similar amounts of variance in microbiome structure. Differential abundance testing identified 11 bacterial species significantly associated with at least one measure of body composition or anthropometry. Ruminococcus gnavus was strongly and consistently associated with trunk fat mass, which is congruent with prior literature. CONCLUSIONS: Microbiome diversity and composition, in particular higher abundance of Ruminococcus gnavus, were associated with greater trunk fat, in addition to other measures of obesity. Longitudinal studies are needed to replicate these findings, and if replicated, randomized trials are needed to determine whether interventions targeting microbiome features such as abundance of Ruminococcus gnavus can lead to reductions in trunk fat and its metabolic sequelae.

Associations of Plastic Bottle Exposure with Infant Fecal Microbiota, Short-Chain Fatty Acids, and Growth.

Background: Plastic exposures have been shown to impact the microbiome, metabolism and growth of animals. However, no human studies have examined how plastic exposures are associated with fecal microbiota, microbial metabolites, or growth. Here we examine the association of plastic bottle feeding with infant fecal microbiota, microbial short-chain fatty acid (SCFA) metabolites, and anthropometry in the first year of life. Methods: 462 infants from the prospective Nurture Birth Cohort were included to examine frequency of plastic bottle feeding (every feeding vs. less than every feeding) at 3 months with anthropometric outcomes (skinfolds, length-for-age, and weight-for-length) at 1 year. A subset of 64 and 67 infants were included in analyses examining the fecal microbiota and fecal SCFAs, respectively. Microbial taxa were measured by 16S rRNA gene sequencing of the V4 region and SCFA concentrations were quantified using gas chromatography at 3 and 12 months of age. Results: After adjustment for potential confounders, less frequent plastic bottle use was associated with lower fecal microbiota alpha Shannon diversity at 3 months (mean difference for plastic bottle used less than every feeding vs. every feeding = -0.53, 95% CI: -0.90, -0.17, p < 0.01) and lower propionic acid concentration at 3 months (mean log + 1 difference for plastic bottle used every feeding vs. less than every feeding = -0.53, 95% CI: -1.00, -0.06, p = 0.03). Furthermore, compared to infants who used plastic bottle at every feeding, infants who were plastic bottle-fed less frequently (1 -3 times/day) at 3 months had significantly lower length-for-age z-scores at 12 months (mean difference= -0.40, 95% CI: -0.72, -0.07, p = 0.016). Conclusion: Plastic bottle exposure may impact early infant gut microbiota and microbial SCFAs, which may in turn affect growth.

A systematic review and meta-analysis of the epidemiological characteristics of COVID-19 in children.

BACKGROUND: Several individual studies from specific countries have reported rising numbers of pediatric COVID-19 cases with inconsistent reports on the clinical symptoms including respiratory and gastrointestinal symptoms as well as diverse reports on the mean age and household exposure in children. The epidemiological characteristics of COVID-19 in children are not fully understood, hence, comprehensive meta-analyses are needed to provide a better understanding of these characteristics. METHODS: This review was conducted in Medline, Scopus, Cochrane library, Embase, Web of Science, and published reports on COVID-19 in children. Data were extracted by two independent researchers and a third researcher resolved disputes. STATA software and the random-effect model were used in the synthesis of our data. For each model, the heterogeneity between studies was estimated using the Q Cochrane test. Heterogeneity and publication bias were calculated using the I2 statistic and Egger's/Begg's tests. RESULTS: The qualitative systematic review was performed on 32 articles. Furthermore, the meta-analysis estimated an overall rate of involvement at 12% (95% CI: 9-15%) among children, with an I2 of 98.36%. The proportion of household exposure was calculated to be 50.99% (95% CI: 20.80%-80.80%) and the proportion of admitted cases was calculated to be 45% (95% CI: 24%-67%). Additionally, the prevalence of cough, fatigue, fever and dyspnea was calculated to be 25% (95% CI: 0.16-0.36), 9% (95% CI: 0.03-0.18), 33% (95% CI: 0.21-0.47) and 9% (95% CI: 0.04-0.15), respectively. It is estimated that 4% (95% CI: 1-8%) of cases required intensive care unit admission. CONCLUSIONS: The pediatric clinical picture of COVID-19 is not simply a classic respiratory infection, but unusual presentations have been reported. Given the high incidence of household transmission and atypical clinical presentation in children, we strongly recommend their inclusion in research and population-based preventive measures like vaccination as well as clinical trials to ensure efficacy, safety, and tolerability in this age group.

Increases in Circulating and Fecal Butyrate are Associated With Reduced Blood Pressure and Hypertension: Results From the SPIRIT Trial.

Background Short chain fatty acids (SCFAs) are microbially derived end products of dietary fiber fermentation. The SCFA butyrate reduces blood pressure (BP) in mouse models. The association of SCFAs, including butyrate, with BP in humans is unclear, due in part to predominantly cross-sectional analyses and different biospecimens (blood versus fecal) for SCFA measurement. Longitudinal studies including both circulating and fecal SCFAs are lacking. Methods and Results We leveraged existing data from the SPIRIT (Survivorship Promotion In Reducing IGF-1 Trial), which randomized 121 adult cancer survivors with overweight/obesity to a behavioral weight-loss intervention, metformin, or self-directed weight-loss. Of participants with baseline serum and fecal SCFAs measured (n=111), a subset had serum (n=93) and fecal (n=89) SCFA measurements 12 months later. We used Poisson regression with robust error variance to estimate baseline associations of SCFAs with hypertension, and we assessed the percent change in SCFAs from baseline with corresponding 12-month changes in BP using multiple linear regression. Baseline fecal butyrate was inversely associated with prevalent hypertension (standardized PR [95%CI]: 0.71 [0.54, 0.92]). A 10% increase in fecal butyrate from baseline was associated with decreased systolic BP (ß [95%CI]: -0.56 [-1.01, -0.10] mm Hg), and a 10% increase in serum butyrate was associated with decreased systolic (ß [95%CI]: -1.39 [-2.15, -0.63] mm Hg) and diastolic (ß [95%CI]: -0.55 [-1.03, -0.08] mm Hg) BPs. Butyrate associations with systolic BP were linear and not modified by sex, race, or intervention arm. Conclusions Increased serum or fecal butyrate is associated with lowered BP. Butyrate may be a target for SCFA-centered BP-lowering interventions. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02431676.

A behavioral weight-loss intervention, but not metformin, decreases a marker of gut barrier permeability: results from the SPIRIT randomized trial.

BACKGROUND/OBJECTIVES: Lipopolysaccharide-binding protein (LBP), a biomarker of gut barrier permeability to lipopolysaccharides, is higher in adults with obesity and type 2 diabetes. Behavioral weight loss and metformin have distinct effects on the gut microbiome, but their impact on gut permeability to lipopolysaccharides is unknown. This study's objective was to determine the effects of a behavioral weight-loss intervention or metformin treatment on plasma LBP. SUBJECTS/METHODS: SPIRIT was a randomized trial of adults with overweight or obesity. Participants were randomized to one of three arms: metformin treatment, coach-directed behavioral weight loss on a DASH diet, or self-directed care (control). Of 121 participants, a random subset (n = 88) was selected to have LBP measured at baseline, 6 months, and 12 months post intervention. Intervention effects on LBP over time were assessed using generalized estimating equations (GEE). We also examined whether the intervention effects were modified by change in diet and weight. RESULTS: Arms were balanced by sex (83% female), race (51% white), and age (mean 60 years), with no differences in baseline LBP (median 4.23 µg/mL). At 1 year, mean weight change was -3.00% in the metformin arm, -3.02% in the coach-directed behavioral weight-loss arm, and +0.33% in the self-directed (control) arm. The corresponding change in LBP was +1.03, -0.98, +1.03 µg/mL. The behavioral weight-loss intervention reduced LBP compared to self-directed care (ß = -0.17, 95% CI: -0.33 to -0.01); no other between-arm comparisons were significant. Behavioral weight-loss participants who reduced dietary fat showed the greatest reductions in 6-month LBP (ß = -2.84, 95% CI: -5.17 to -0.50). CONCLUSIONS: Despite similar weight loss in the behavioral weight loss arm and the metformin arm, only the behavioral weight-loss intervention reduced LBP compared to control. Lifestyle weight-loss interventions that promote a DASH diet may be effective at reducing gut barrier permeability to lipopolysaccharides. CLINICAL TRIALS REGISTRATION NUMBER: NCT02431676, https://clinicaltrials.gov.

Relative associations of abdominal and thigh compositions with cardiometabolic diseases in African Caribbean men.

BACKGROUND: Regional body compositions are differentially associated with cardiometabolic risk factors. Simultaneous inclusion of both upper and lower body composition predictors in models is not often done, and studies which do include both measures (1) tend to exclude some tissue(s) of potential metabolic relevance, and (2) have used study populations with underrepresentation of individuals with African ancestries. Further, most body composition analyses do not employ compositional data analytic approaches, which may result in spurious associations. OBJECTIVE: The objective of this analysis was to assess associations of abdominal and thigh adipose (AT) and muscle tissues with hypertension and type 2 diabetes using compositional data analytic methods. RESEARCH DESIGN AND METHODS: This cross-sectional analysis included 610 African Caribbean men (median age: 62 years; mean BMI: 27.8 kg/m2). Abdominal (three components: subcutaneous [ASAT] and visceral [VAT] AT, 'other' abdominal tissue) and mid-thigh (four components: subcutaneous and intermuscular AT, muscle, bone) compositions were measured by computed tomography; additive log ratio transformations were applied to each composition. Regression models were used to simultaneously assess associations of abdominal and thigh component ratios with continuous risk factors (blood pressures, fasting glucose and insulin, HOMA-IR) and disease categories. RESULTS: A two-fold increase in ASAT:'Other' ratio was associated with higher continuous risk factors and with odds of being in a higher hypertension (OR: 1.77, 95%CI: 1.10-2.84) or diabetes (OR: 1.81, 95%CI: 1.06-3.10) category. A two-fold increased VAT ratio was only associated with higher log-insulin and log-HOMA-IR (ß = 0.10, p < 0.05 for both), while a two-fold increased thigh muscle:bone ratio was associated with a lower diabetes category (OR: 0.37, 95%CI: 0.14-1.01). CONCLUSIONS: These findings support ASAT as a significant driver of cardiometabolic disease in African Ancestry populations, independent of other abdominal and thigh tissues.

Associations of Thigh and Abdominal Adipose Tissue Radiodensity with Glucose and Insulin in Nondiabetic African-Ancestry Men.

OBJECTIVE: Decreased radiodensity of adipose tissue (AT) located in the visceral AT (VAT), subcutaneous AT (SAT), and intermuscular AT (IMAT) abdominal depots is associated with hyperglycemia, hyperinsulinemia, and insulin resistance independent of AT volumes. These associations were sought in African-ancestry men, who have higher risk for type 2 diabetes and have been underrepresented in previous studies. METHODS: This cross-sectional analysis included 505 nondiabetic men of African-Caribbean ancestry (median age: 61 years; median BMI: 26.8 kg/m2 ) from the Tobago Health Study. AT volumes and radiodensities were assessed using computed tomography, including abdominal (VAT and SAT) and thigh (IMAT) depots. Associations between AT radiodensities were assessed with fasting serum glucose and insulin and with insulin resistance (updated homeostatic model assessment of insulin resistance, HOMA2-IR). RESULTS: Higher radiodensity in any AT depot was associated with lower log-insulin and log-HOMA2-IR (ß range: -0.16 to -0.18 for each; all P < 0.0001). No AT radiodensity was associated with glucose. Thigh IMAT radiodensity associations were independent of, and similar in magnitude to, VAT radiodensities. Model fit statistics suggested that AT radiodensities were a better predictor for insulin and insulin resistance compared with AT volumes in individuals with overweight and obesity. CONCLUSIONS: AT radiodensities at multiple depots are significantly associated with insulin and insulin resistance in African-ancestry men.

Association of Lipopolysaccharide-Binding Protein With Aging-Related Adiposity Change and Prediabetes Among African Ancestry Men.

OBJECTIVE: Cross-sectional studies suggest that lipopolysaccharide-binding protein (LBP) may be associated with obesity and metabolic disorders. However, prospective studies examining LBP are lacking. This prospective study investigated the association between LBP and metabolic abnormalities in 580 African ancestry men (mean age, 59.1 ± 10.5 years). RESEARCH DESIGN AND METHODS: We measured fasting serum LBP at baseline. Changes in adiposity and glucose homeostasis as well as case subjects with new type 2 diabetes and impaired fasting glucose (IFG) were assessed at a follow-up visit ~6 years later. Baseline LBP values were tested across quartiles for linear trend with metabolic measures. Multivariable logistic regression was used to determine the odds of new cases of IFG or diabetes per 1-SD greater baseline LBP. RESULTS: LBP was significantly associated with baseline BMI, waist circumference, whole-body and trunk fat, skeletal muscle density, fasting serum insulin, and HOMA-insulin resistance (IR) (all P < 0.01). Greater baseline LBP was significantly associated with longitudinal increases in the percentage of trunk fat (P = 0.025) and HOMA-IR (P = 0.034), but only borderline so with a decrease in skeletal muscle density (P = 0.057). In men with normal glucose, baseline LBP was associated with increased odds of having IFG at follow-up after adjustment for age, baseline trunk fat, and lifestyle factors (odds ratio per 1-SD LBP: 1.51; 95% CI 1.02-2.21). This association was attenuated after additional adjustment for change in trunk fat (P = 0.067). CONCLUSIONS: LBP may be a marker of prediabetes. Some of this association appears to be mediated through increased central and ectopic skeletal muscle adiposity.