Dietary Patterns, Fiber Intake and Microbial-Derived Isobutyrate Are Associated With Executive Function in Toddlerhood

Objectives

Early childhood is characterized by stabilization of the gut microbiome and rapid maturation of executive functions (EF; cognitive flexibility [F]; inhibitory self-control [ISC]; emergent metacognition [EM]), which are vital to the regulation of goal-directed behaviors, academic and social success. While diet in school-aged children and gut microbial-derived volatile fatty acids (VFA) in rodent models are linked to EFs, few studies have explored these in early life among humans. The present study investigated the extent to which dietary patterns, fiber intake and fecal VFA predict EF at 24 mo.

Methods

Parents and 24-mo-old children (N = 291) were recruited from the STRONG Kids 2 cohort study. Parent reported surveys were used to assess EF (Behavioral Rating Inventory of Executive Function for Preschoolers) and diet (Block Food Frequency Questionnaires). To derive dietary patterns, raw frequency responses for diet were used to create 23 food groups, which were input into principle component analysis. Analyses were independent of sex, socioeconomic status and energy intake.

Results

Two distinct dietary patterns explaining 30% of the overall variance in diet were evident: higher consumption of fried and sweet foods (DP1) and of vegetables and fruits (DP2). On average, toddlers consumed below the recommendation for fiber intake, 9.10 g/1000 kcals per day. Higher DP1 scores were associated with poorer overall and construct-specific EF (EF: b = 6.146, p = 0.005; ISC: b = 4.458, p = 0.032; F: b = 4.522, p = 0.019; EM: b = 7.322, p = 0.002). DP2 was not associated with EF. Toddlers with lower energy-adjusted fiber intake had significantly poorer EF (EF: b = −1.696, p = 0.009; ISC: b = −1.729, p = 0.004; F: b = −1.149, p = 0.043; EM: b = −1.659, p = 0.018). Before adjustment for fiber intake, higher isobutyrate was predictive of poorer EF (EF: b = 0.017, p = 0.015; ISC: b = 0.014, p = 0.036; EM: b = 0.018, p = 0.018). Adjustment for fiber intake nullified the association with ISC and attenuated associations with EF and EM.

Conclusions

A western-style diet pattern and microbial-derived isobutyrate may have negative implications for EF in toddlers. Additionally, dietary fiber has the potential to influence these relationships.

Funding Sources

Supported by the NIH, the National Dairy Council and a USDA National Needs fellowship (AM).

PSIII-17 Effects of Dietary Tributyrin in Young Pigs Experiencing Colitis

Disruption of intestinal integrity and function due to inflammatory mediators in young pigs has economic implications for swine producers. In this study, we investigated the effects of oral gamma-cyclodextrin-encapsulated tributyrin (TBCD) in young pigs experiencing dextran sodium sulfate (DSS)-induced colitis. Pigs (n = 32 boars) were weaned at postnatal day (PND) 2, allotted to treatment based on litter of origin and body weight (BW), and reared artificially over a 28-d period. Treatment groups included: 1) control (nutritionally adequate milk replacer, no DSS), 2) DSS (control diet plus oral DSS), and 3) DSS+TBCD (control diet supplemented with 8.3g of TBCD per kg reconstituted milk replacer plus oral DSS). Colitis was induced by orally administering DSS at 1.25 g/kg BW/d from PND 14-18. Milk replacer and water were provided ad libitum throughout the study. At study conclusion, pigs were euthanized for collection of samples to measure intestinal morphology and volatile fatty acids. All data were analyzed by ANOVA using the MIXED procedures of SAS. Control and DSS pigs had similar BW throughout the study, while DSS+TBCD pigs exhibited decreased (P < 0.05) BW starting around PND 15. Additionally, BW gain was decreased (P < 0.05) in DSS+TBCD compared with control, and milk disappearance was decreased (P < 0.05) in DSS+TBCD when compared with control and DSS. Relative cecal butyrate was increased (P < 0.05) in DSS+TBCD pigs, compared with the control. DSS and DSS+TBCD treatments had increased (P < 0.05) absolute butyrate in the ascending colon compared with the control. Mucosal width and total lesion scores were responsive to treatment, with DSS+TBCD pigs exhibiting increased (P < 0.05) values in the ascending and descending colon compared with control. Overall, the negative effects of DSS-induced colitis were not mitigated by dietary encapsulated tributyrin in young pigs.

324 Milk Fat Globule Membrane from Bovine Milk on Brain Development of Early Life

The milk fat globule membrane (MFGM) is instrumental for the fat delivery system into human and bovine milk, but is typically removed during the manufacture of infant formula. MFGM contains components that may impact neurodevelopment, including sialic acid, gangliosides, sphingomyelin, choline, glycerophospholipids, proteins, and cholesterol. This presentation will review the clinical trial evidence linking MFGM supplementation to beneficial outcomes in infants and will describe potential mechanistic evidence linking MFGM with neurocognitive outcomes arising from preclinical studies in piglets. Infants fed formula supplemented with a MFGM (4% total protein) from 2 to 6 months of age had improved neurocognitive development at 1 year of age compared to infants fed standard formula. Infants fed formula with MFGM (5.0 g/L) and lactoferrin (0.6 g/L) for 1 year had an accelerated neurodevelopmental profile at 1 year and improved language subcategories at 18 months compared to infants fed a standard formula. To investigate potential mechanisms, piglets were fed a CONT formula or a TEST formula with MFGM and lactoferrin at the same concentrations from 2 to 31 days of age. Piglets underwent spatial T-maze testing to assess learning and memory, and magnetic resonance imaging to measure brain micro- and macrostructure. TEST piglets had lower radial and mean diffusivities in the internal capsule, suggesting greater myelination. The internal capsule contains motor and sensory projections from the cortex to corticospinal tract. Piglets on the CONT diet displayed shorter latency to choice in the T-maze compared to TEST piglets, potentially indicating anxiety-like behaviors or greater impulsivity. Aspects of the microbiome-gut-brain-axis (MGBA) were investigated to uncover potential mechanisms. TEST piglets had higher protein abundance of tyrosine hydroxylase and vasoactive intestinal peptide, longer villi and greater disaccharidase activity in the small intestine and differences in microbial abundances in the ascending colon and feces, suggesting potential modulation of the MGBA by MFGM.

Early Life Factors Predictive of Weight Status in 2 Year-Olds

Objectives

The extent to which early life factors predict weight status by age two is unclear. This study elucidated early life factors predictive of BMI-for-age z-score (MN24 BMI) in 2-year-olds in the ongoing STRONG Kids 2 longitudinal study.

Methods

At registration, 6 weeks, 3, 12, 18, and 24 months, parents (N = 126) completed online surveys (questions derived from CDC Infant Feeding Practices questionnaire, Short Form of the MOS Health survey, and Block Kids Food Frequency Questionnaire (Ages 2–7; Nutrition Quest) for diet MN21–24). Height and weight were collected at home visits. Child BMI-for age z-scores were based on WHO growth standards, and dietary patterns at MN24 were derived by principal component analysis (PCA). Mode of delivery (i.e., vaginal or caesarean), timing of introduction to solids, dietary patterns, child's BMI z-score and feeding methods (i.e., exclusive formula or breastfeeding, or both), and maternal weight were obtained. Multiple regression modelling determined the explanatory power of these factors on MN24 BMI.

Results

Modelling revealed a significant regression equation (P < .001), with an R2 of .359. MN12 BMI-for-age z-score (MN12 BMI) (β = .555, P < .001) explained 31.2% of the variance in MN24 BMI. Child feeding method at MN3 (β = –.218, P = .003) accounted for 4.7% of the variance in MN24 BMI.

Conclusions

Children with a greater MN12 BMI have a higher MN24 BMI, while those who undergo breastfeeding at MN3 have a lower MN24 BMI. Future studies will expand on these findings by examining if the predictive power of these early life factors on BMI persists in later life.

Funding Sources

Grants from the National Dairy Council to Sharon Donovan and Barbara H. Fiese (CoPI's), and the Gerber Foundation and NIH R01 DK107561 to Sharon Donovan.

Bacterial Co-Occurrence Patterns Between Human Milk and Microbial Sites of Breastfeeding Dyads

Objectives

The human milk (HM) microbiota is predicted to originate from the maternal gastrointestinal tract, saliva and breast skin, and infant saliva. Though compositionally distinct, these habitats are strongly associated during breastfeeding. Vertical microbial transmission from mother to infant has been documented, but complex microbial interactions between sites are less clear. Herein, ecological networks between HM bacteria and other microbial sites of breastfeeding dyads were assessed to investigate the origin of the HM microbiota and how it may shape the infant gut microbiota.

Methods

DNA was extracted from maternal and infant saliva, HM, breast skin, and maternal and infant stool samples collected at 6 weeks postpartum from 33 mother-infant pairs. The V3-V4 region of the 16S rRNA gene was sequenced and taxonomy was assigned using QIIME 2. Co-occurrence patterns among genus-level abundance data were analyzed in CoNet (Cytoscape 3.0).

Results

Twenty-one significant co-presence relationships were identified between HM and other microbial communities. Associations spanned from six nodes in HM including Corynebacterium, Cutibacterium, Gemella, Rothia, Veillonella, and Actinomyces. Co-presence between Cutibacterium, Veillonella, Actinomyces, and Corynebacterium on skin and HM were identified, supporting breast skin as a principal contributor to the HM microbiota. Interestingly, Bifidobacterium in infant saliva was associated with Gemella and Rothia in HM. The greatest number of relationships existed between HM and infant stool. HM Gemella, Actinomyces, and Corynebacterium were associated with Bacteroides in infant stool; HM Actinomyces was also associated with infant fecal Escherichia-Shigella and Eggerthella. Additional relationships were identified between HM and maternal saliva and fecal microbiota.

Conclusions

Several unique ecological relationships exist between HM and microbial sites of breastfeeding dyads. Whether these relationships are indicative of proximity, mutualism, or are biomarkers of other host-microbe interactions remains to be determined. These data will be useful to uncover mechanisms driving microbial community organization and potential targets for microbial modulation in this population.

Funding Sources

National Dairy Council, NIH, The Gerber Foundation, The Doris Kelley Christopher Foundation.

Fecal Microbiota Enterotypes of Preterm Infants at the Neonatal Intensive Care Unit (NICU) in Association with Dietary and Clinical Factors

Objectives

The gut microbiota of preterm infants (PTI) differs from that of term infants, with higher abundances of pathogenic bacteria and late acquisition of beneficial bacteria. This dysbiosis is affected by different types of milk and milk fortifiers fed to PTI, exposure to antibiotics after birth, and long hospitalization periods. Different enterotypes have been proposed to classify the gut bacteria ecosystems in adults, but little data exits regarding the PTI gut microbiota. Thus, the objective herein was to investigate gut microbial enterotypes of PTI infants.

Methods

PTI were followed from birth until NICU discharge. Data including daily feeding information and medications were obtained from the medical records. Freshly voided stool samples were collected, bacterial DNA was extracted and the V3-V4 regions of the 16S rRNA were sequenced. Enterotypes were determined using the partitioning around medoids clustering algorithm and the Jensen-Shannon divergence method using RStudio.

Results

A total of 551 stool samples were collected from 97 PTI. At genus level, two enterotypes were obtained; enterotype A (EA) was characterized by a high abundance (62%) of Escherichia-Shigella and Staphylococcus, whereas Enterobacteriaceae, Clostridium sensu stricto 1 and Klebsiella accounted 55% of relative abundance for Enterotype B (EB). Alpha diversity (Shannon index) was higher (P < 0.0001) in EB. In the earliest sample collected after birth (2.2 ± 1.1 weeks of life), the majority of PTI (64%) belonged to EB, but 37% of PTI switched enterotypes during their hospital stay, most of these changed from EA to EB. The change on enterotypes occurred at 4.6 ± 2.7 weeks of life. Bovine milk-based fortifier (BMF) and abundance of Escherichia-Shigella were positively associated in EA, whereas, this correlation was negative for EB. Similarly, Enterobacteriaceae abundance was positively correlated with the use of antibiotics in EA, but was negatively correlated in EB.

Conclusions

The gut microbiota of PTI was more likely to belong to a more diverse enterotype. There were opposite effects between both enterotypes to exposure to BMF and antibiotics. This suggests that responses to dietary and clinical factors could be dependent upon the characteristics of the gut microbiota of PTI.

Funding Sources

Seed grant Carle Foundation Hospital and University of Illinois. CONACyT Graduate Fellowship.

Screen Time is Related to Dietary Intake in Children at 24-Months-of-Age

Objectives

Screen time throughout childhood is positively related to anthropometric measures, mediated partially through its impact on diet quality. Existing literature lacks specific data for 24 months (24MN) children and focuses primarily on television screen time rather than all sources of screen time (smart phones, tablets, and video streaming services). Thus, we explored the relationship between screen device usage and diet quality at this early age.

Methods

Parents and 24MN children (N = 396) were recruited from the STRONGKids 2 cohort study. Data included parent and child anthropometric measurements, physical activity time (Sports, Play, and Active Recreation for Kids Survey), dietary intake (Block Food Frequency Questionnaires), and the types and duration of screen time usage by the child (Common Sense Media Survey). Calories from macronutrients, sweets, added sugar, dietary fiber, and fruit and vegetable consumption were used to assess diet quality.

Results

26% of children exceeded the Academy of Pediatrics Guidelines of <2 h screen time per day. TV, DVDs, and shows on cellphones accounted for 79% of child screen time. 26% of children were overweight or obese, although BMI z-score at 24 MN was not related to screen time, physical activity time, or diet factors. Parent and child diet quality were related.; However, independent of parent diet, education, ethnicity, gender, and BMI, total screen time were associated with kcal consumed through sweets (r = 0.147, P = 0.014), added sugar intake in grams (r = 0.137, P = 0.023), and fruit consumption (r = −0.235, P < 0.001). Passive screen use (TV, DVDs, shows on a cell phone or computer) was associated with total kcals (r = 0.127, P = 0.036), kcals from sweets (r = 0.137, P = 0.023) and added sugar intake (r = 0.138, P = 0.022), and fruit (r = −0.260, P < 0.001) and vegetable consumption (r = −0.119, P = 0.049). Active screen use (playing games on a console, computer, cell phone, or other handheld device) was related to % fat intake (r = −0.119, P = 0.048).

Conclusions

Total and passive screen time at 24 MN are associated with factors indicative of poor diet quality, which could negatively impact child health.

Funding Sources

Supported by the NIH and the National Dairy Council. Arden McMath was supported by a United States Department of Agriculture (USDA) fellowship.

Identification and Phenotypic Evaluation of Microbes Isolated from Breast and Formula-fed Infants Delivered Either Vaginally or by Cesarean Section (P11-075-19)

Objectives

Many factors influence the development of the infant microbiota. Based on 16S rDNA sequencing information, the type of feeding, i.e., breast vs formula, has been shown to be the most important factor, with route of delivery having transient effects in the early postpartum period. However, few recent studies have isolated individual strains from human infants or have investigated the functional properties of the infant gut microbes. We used a 2 × 2 experimental design with the goal of determining how diet and delivery interact to shape infant microbiota composition and metabolic activity.

Methods

Fresh fecal samples were collected from 3-month-old infants who were either exclusively breast- (BF) or formula-fed (FF) and cesarean- (CD) or vaginally-delivered (VD). Samples were diluted and plated on two types of media: Gut Microbiota Medium (GMM) or MRS medium. Individual colonies were picked, purified and their 16S rRNA gene sequenced for identification. These isolates were screened for growth on various carbon substrates, including human milk oligosaccharides, prebiotics and volatile fatty acids for 24–36h. Medium supernatant was collected and metabolic profiles assessed by HPLC.

Results

More than 150 bacterial strains have been isolated and identified from infant fecal samples to date. Isolates from BF/VD fecal samples were predominantly from the phylum Actinobacteria (dominated with Bifidobacterium) followed by Firmicutes and Proteobacteria. In contrast, isolates from FF/VD or FF/CD infants were primarily from the phylum Firmicutes with only a few Actinobacterial and Proteobacterial isolates. Quantitatively, most isolates represented the genera Bifidobacterium, followed by Enterococcus, and Ruminococcus. On-going phenotypic evaluation of the isolated strains for the growth and utilization of various carbon sources and metabolic profiles will provide insight into species- and strain-specific utilization of common prebiotics in human milk and infant formula.

Conclusions

This collective data will provide novel insights on how the physiological and metabolic function of the infant gut microbiota is influenced by route of delivery and early infant nutrition.

Funding Sources

NIH R01DK107561.

Early Life Nutrient Intake Is Associated with Weight-for-Length Z-Scores at 3 and 12 Months (P11-127-19)

Objectives

Rapid weight gain over the first 12 months of life is a risk factor for childhood obesity. While macronutrient concentrations in human milk (HM) or infant formula (IF) have been associated with rapid weight gain or weight-for-length Z-scores later in infancy, few studies evaluate milk intake. Therefore, the objective was to assess how nutrient intake at 6 weeks of age, across multiple feeding modes, influences growth over the first year of life.

Methods

Data were collected from 222 healthy mother-infant pairs enrolled in the STRONG Kids 2 Cohort. Twenty-four hour test weighing was conducted to measure milk intake volume and a human milk sample was collected at 6 weeks postpartum. Milk samples were analyzed for total protein (Bradford assay), fat (total lipid extraction), and carbohydrate (Orcinol assay). Mode of feeding at 6 weeks, servings per day of HM and/or IF, and formula type were reported by mothers. For exclusively breastfeeding infants, HM macronutrient concentrations and total intake were used to calculate nutrient intake. For those receiving IF, the numbers of feedings from HM and/or from IF and formula nutrition information were also used to calculate nutrient intake. Infant length and weight collected at study visits were used to calculate weight-for-length Z-scores (WFL-Z). Mixed linear models were used to measure associations between macronutrient intake, total calories, total milk intake and WFL-Z at 3 months and 12 months of age. Models were controlled for 6-week feeding mode, breastfeeding duration, and timing of solid food introduction.

Results

At 3 months, WFL-Z was associated with total milk (P = 0.03) and caloric intake (P = 0.03) as well as intake of fat (P = 0.02), carbohydrate (P = 0.05), and protein (P = 0.03). WFL-Z at 12 months was associated with protein (P = 0.02) and fat (P = 0.04) intakes at 6 weeks but no longer associated with other measures of nutrient intake.

Conclusions

Our results support previous findings suggesting that high protein intake in infancy contributes to obesity risk. While milk intake was only quantified once, data show that nutrient intake at 6 weeks-of-age influences future growth. More research is needed to understand other lifestyle and nutritional factors between 3 and 12 months that contribute to growth trajectories and weight during infancy.

Funding Sources

National Dairy Council, NIH RO1DK107561, The Gerber Foundation, The Doris Kelley Christopher Foundation.

Osteopontin-Enriched Algae Modulates the Gut Microbiota Composition in Weaning Piglets Infected with Enterotoxigenic Escherichia Coli (P06-069-19)

Objectives

Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhea in human infants and young farm animals. Osteopontin (OPN), a glycoprotein present in high concentration in human milk, has immunomodulatory functions, which could indirectly impact the microbiota. Furthermore, a previous study has shown fecal microbiota composition differs between wild-type and OPN knockout mice. Herein, the effects of OPN-enriched algae on the gut microbiota composition and volatile fatty acid (VFA) concentrations of ETEC-infected piglets were assessed.

Methods

Naturally-farrowed piglets were sow-reared for 21 days and then randomized to two weaning diets: WT (formula + 1% wild-type algae) or OPN (formula + 1% OPN-enriched algae). On postnatal day (PND) 31, all piglets were infected orally with a live culture of ETEC (1010 colony-forming unit/3 mL dose) daily for three consecutive days. On PND 41, ascending colon (AC) contents were collected. Gut microbiota was assessed by sequencing V3-V4 regions of 16S rRNA gene and VFAs were determined by gas chromatography. Alpha-diversity and VFAs were analyzed using PROC MIXED procedure of SAS. Beta-diversity was evaluated by permutational multivariate analysis of variance (PERMANOVA) and differential abundance analysis on the bacterial genera was performed using DESeq2 package of R.

Results

Shannon indices were lower in the AC contents of OPN piglets compared to WT piglets. The overall colonic microbiota of OPN piglets differed from that of WT piglets (PERMANOVA P = 0.015). At genus level, OPN-enriched algae increased the abundance of Streptococcus, decreased the abundances of Sutterella, Candidatus Soleaferrea, dga-11 gut group, Rikenellaceae RC9 gut group, Ruminococcaceae UCG-010, unculturedRuminococcaceae, Prevotella 2 and 7 compared to piglets consuming wild-type algae (P < 0. 05). OPN piglets also had higher (P < 0.05) concentrations of acetate, propionate, butyrate and valerate compared to WT.

Conclusions

In ETEC infected piglets, 1% OPN-enriched algae decreased alpha-diversity and modulated the microbiota composition and VFA profiles compared to 1% WT algae. Other studies have shown that OPN inhibits biofilm formation in vitro, but future research is needed to assess in vivo microbiome-modulation mechanisms.

Funding Sources

Triton Algae Innovations.

Differential Effects of Mother's Own Milk, Donor Human Milk and Formula Feeding on the Fecal Microbiota of Preterm Infants During Their Stay in the Neonatal Intensive Care Unit (FS04-06-19)

Objectives

Preterm infants (PTI) are at risk for many complications including growth retardation, and co-morbidities, such as necrotizing enterocolitis. Microbiome composition is influenced by diet and other environmental factors or medical treatments. The use of mother's own milk (MOM) or donor human milk (DHM) is recommended over preterm formula (PF). However, when there is insufficient human milk (HM), PF is used. The objective of this study was to evaluate how each type of feed (MOM, DHM and PF) affects PTI gut microbiota composition during the infant's Neonatal Intensive Care Unit (NICU) stay.

Methods

This cohort study followed PTI from birth until discharge from the NICU. Medical records, weekly weight and daily feed volume were recorded. Stool samples (n = 551) were collected from the infant's diaper. Total DNA was extracted to assess microbiome composition, V3-V4 regions of 16S rRNA gene were amplified and sequenced using Illumina HiSeq and data were analyzed in Qiime2.

Results

PTI (n = 97; 63% female) were enrolled with mean gestational age (GA) of 29 ± 2.45 weeks, birth weight of 1.27 ± 0.43 kg, and 78% delivered by C-section. Infants were discharged at 37 ± 2.06 weeks corrected GA (cGA) weighing 2.69 ± 0.57 kg. At birth, PTI from black mothers (27%) had higher (P < 0.05) microbiota diversity (observed OTUs) than other ethnicities. No differences in microbiota were found for sex or mode of delivery in the first 14d postpartum. PF was not fed prior to 34 weeks cGA. Over time, microbiota beta diversity differentiated by cGA and type of feeding. In HM-fed PTI, when > 50% MOM was consumed, the abundance of Clostridium, Enterococcus, and Staphylococcus was higher (P < 0.05) than DHM. When > 50% DHM was fed, Bifidobacteium, Paeniclostridium, Staphylococcus and Veillonela increased (P < 0.05) compared to > 50% MOM. In PTI fed both HM and PF, in those consuming > 33% PF, the abundance of Clostridium difficile was higher and Staphylococcuslower than either MOM or DHM (P < 0.05).

Conclusions

The development of fecal microbiota of PTI was modulated by cGA, such that abundance and diversity increased over time. The fecal microbiota was differently modified by consumption of human milk, either MOM or DHM, versus PF. Ongoing studies are investigating the effect of milk fortifiers and other NICU environmental factors on the gut microbiota.

Funding Sources

Supported by a seed grant from Carle Foundation Hospital and University of Illinois and a CONACyT Graduate Fellowship.

State Laws Governing Competitive Foods and Beverages Sold in Schools and Childhood Obesity among Children with Special Healthcare Needs, 2007-2016

Objective In this study, we assessed the impact of state laws governing competitive foods/beverages sold in schools on childhood overweight/obesity among children aged 10-17 years with and without special healthcare needs (SHCN). Methods Individual-level data from 2007-2008, 2011-2012, and 2016 National Survey of Children's Health (N = 108,009) were merged to data on state codified laws regulating competitive foods/beverages sold in schools based on children's residential state and survey year. State random-effect logistic regressions were performed to estimate the odds of childhood overweight/obesity in relation to the presence and strength of competitive food/beverage laws, adjusting for child/family characteristics and state soda sales tax. Results No association between state laws governing competitive foods/beverages sold in schools and childhood overweight/obesity was identified among children with and without SHCN. In addition, no impact of state soda sales tax on childhood overweight/obesity was found among children with SHCN. Conclusions No protective effect of state laws governing competitive foods/beverages sold in schools against obesity risk among children with SHCN was revealed. This study has design and measurement limitations. Future research should replicate findings of this study and assess school district competitive food/beverage policies in relation to adiposity among this highly vulnerable child population.

Using corticosteroids to reshape the gut microbiome: implications for inflammatory bowel diseases

BACKGROUND

Commensal gut microbiota play an important role in regulating metabolic and inflammatory conditions. Reshaping intestinal microbiota through pharmacologic means may be a viable treatment option. We sought to delineate the functional characteristics of glucocorticoid-mediated alterations on gut microbiota and their subsequent repercussions on host mucin regulation and colonic inflammation.

METHODS

Adult male C57Bl/6 mice, germ-free, Muc2-heterozygote (±), or Muc2-knockout (-/-) were injected with dexamethasone, a synthetic glucocorticoid, for 4 weeks. Fecal samples were collected for gut microbiota analysis through 16S rRNA terminal restriction fragment length polymorphism and amplicon sequencing. Intestinal mucosa was collected for mucin gene expression studies. Germ-free mice were conventionalized with gut microbes from treated and nontreated groups to determine their functional capacities in recipient hosts.

RESULTS

Exposure to dexamethasone in wild-type mice led to substantial shifts in gut microbiota over a 4-week period. Furthermore, a significant downregulation of colonic Muc2 gene expression was observed after treatment. Muc2-knockout mice harbored a proinflammatory environment of gut microbes, characterized by the increase or decrease in prevalence of specific microbiota populations such as Clostridiales and Lactobacillaceae, respectively. This colitogenic phenotype was transmissible to IL10-knockout mice, a genetically susceptible model of colonic inflammatory disorders. Microbiota from donors pretreated with dexamethasone, however, ameliorated symptoms of inflammation.

CONCLUSIONS

Commensal gut bacteria may be a key mediator of the anti-inflammatory effects observed in the large intestine after glucocorticoid exposure. These findings underscore the notion that intestinal microbes comprise a "microbial organ" essential for host physiology that can be targeted by therapeutic approaches to restore intestinal homeostasis.

Diet creates metabolic niches in the "immature gut" that shape microbial communities

Although diet composition has been implicated as a major factor in the etiology of various gastrointestinal diseases, conclusive evidence remains elusive. This is particularly true in diseases such as necrotizing enterocolitis where breast milk as opposed to commercial formula appears to confer a "protective effect" to the "immature gut." Yet the mechanism by which this occurs continues to remain speculative. In the present study we hypothesize that the basic chemical composition of diet fundamentally selects for specific intestinal microbiota which may help explain disparate disease outcome and therapeutic direction. Complimentary animal and human studies were conducted on young piglets (21 d.)(n = 8) (IACUC protocols 08070 and 08015) and premature infants (adjusted gestational age 34-36 weeks) (n = 11) (IRB Protocol 15895A). In each study, cecal or stool contents from two groups (Breast milk-fed (BF) vs. Formula-fed (FF)) were analyzed by gas chromatography/mass spectrometry (GC/MS) and comprehensive metabolic profiles generated and compared. Concurrently, bacterial community structure was assayed and respective representative microbiota of the groups determined by 16S rRNA gene amplicon pyrosequencing. Statistical modeling and analysis was done using SIMCA-P+ and R software. GC/MS metabolomics identified clear differences between BF and FF groups in the intestinal environment of piglets and humans. Sugars, amino-sugars, fatty acids, especially unsaturated fatty acids, and sterols were identified as being among the most important metabolites for distinguishing between BF and FF groups. Joint analysis of microbiota and metabolomics pinpointed specific sets of metabolites (p < 0.05) associated with the dominant bacterial taxa. The chemical composition of diet appears to have a significant role in defining the microbiota of the immature gut. Tandem analysis of intestinal microbial and metabolic profiles is potentially a powerful tool leading to better understanding of the role of diet in disease perhaps even leading to specific strategies to alter microbial behavior to improve clinical outcome.

Knowledge, attitudes, and beliefs about nutrition and childhood overweight among WIC participants

This study assessed knowledge, attitudes, and beliefs about nutrition, physical activity, and health risks related to childhood overweight among Women, Infants, and Children participants. Most (n = 165) were knowledgeable about causes/health risks of overweight (90%). The belief that "some people are born big or thin . . . " varied by education level (P < 0.05). Concerning activity, many (white non-Hispanic, 53%; African-American 69%) reported their children spending 2 to 3 hours per day watching television and playing video games, with 10% white non-Hispanic and 21% of African-American reporting 4 hours or more (P < 0.05). Beliefs related to the risk of overweight and activity level of the children differed among ethnic groups.

Gut microbial gene expression in mother-fed and formula-fed piglets

BACKGROUND

Effects of diet on the structure and function of gut microbial communities in newborn infants are poorly understood. High-resolution molecular studies are needed to definitively ascertain whether gut microbial communities are distinct in milk-fed and formula-fed infants.

METHODOLOGY/PRINCIPAL FINDINGS

Pyrosequencing-based whole transcriptome shotgun sequencing (RNA-seq) was used to evaluate community wide gut microbial gene expression in 21 day old neonatal piglets fed either with sow's milk (mother fed, MF; n = 4) or with artificial formula (formula fed, FF; n = 4). Microbial DNA and RNA were harvested from cecal contents for each animal. cDNA libraries and 16S rDNA amplicons were sequenced on the Roche 454 GS-FLX Titanium system. Communities were similar at the level of phylum but were dissimilar at the level of genus; Prevotella was the dominant genus within MF samples and Bacteroides was most abundant within FF samples. Screened cDNA sequences were assigned functional annotations by the MG-RAST annotation pipeline and based upon best-BLASTX-hits to the NCBI COG database. Patterns of gene expression were very similar in MF and FF animals. All samples were enriched with transcripts encoding enzymes for carbohydrate and protein metabolism, as well as proteins involved in stress response, binding to host epithelium, and lipopolysaccharide metabolism. Carbohydrate utilization transcripts were generally similar in both groups. The abundance of enzymes involved in several pathways related to amino acid metabolism (e.g., arginine metabolism) and oxidative stress response differed in MF and FF animals.

CONCLUSIONS/SIGNIFICANCE

Abundant transcripts identified in this study likely contribute to a core microbial metatranscriptome in the distal intestine. Although microbial community gene expression was generally similar in the cecal contents of MF and FF neonatal piglets, several differentially abundant gene clusters were identified. Further investigations of gut microbial gene expression will contribute to a better understanding of normal and abnormal enteric microbiology in animals and humans.

Swine in Biomedical Research: Creating the Building Blocks of Animal Models

The opportunities for utilizing swine biomedical models are immense, particularly in models that address lifestyle issues (nutrition, stress, alcohol, drugs of abuse, etc.). However, in order to fully capitalize upon the promise, there needs to be a more general recognition of these cofactors, such as nutrition, as key modulators of phenotype via genomic, epigenetic, and postgenomic mechanisms. Furthermore, increased interactions between nutrition scientists and clinical and fundamental researchers in other disciplines, including developmental biology, immunology, neuroscience, oncology, and cardiovascular and gastrointestinal physiology, are required. Closing discussions focused on the need for future conferences at more frequent intervals to support interactions between the various disciplines. This was especially critical because of the global distribution of investigators.

Forensic entomology: what can maggots tell us about murders?

On 29 September 1935, the dismembered remains of two human bodies were discovered in a ravine known as the Devil's Beef Tub, in Dumfriesshire, Scotland. On examination, it was apparent that many of the body parts were infested by maggots.

Candidate gene isolation and comparative analysis of a commonly deleted segment of 7q22 implicated in myeloid malignancies

Monosomy 7 and deletion of 7q are recurring abnormalities in malignant myeloid diseases. Here we extensively characterize an approximately 2-Mb commonly deleted segment (CDS) of 7q22 bounded by D7S1503 and D7S1841. Approximately 1.8 Mb of sequence have been generated from this interval, facilitating the construction of a transcript map that includes large numbers of genes and ESTs. The intron/exon organization of seven genes and expression patterns of three genes were determined, and leukemia samples were screened for mutations in five genes. We have used polymorphic markers from this region to examine leukemia cells for allelic loss within 7q22. Finally, we isolated mouse genomic clones orthologous to several of the characterized human genes. Fluorescence in situ hybridization studies using these clones indicate that a region of orthologous synteny lies on proximal mouse chromosome 5. These resources should greatly accelerate the pace of candidate gene discovery in this region.

Deliberate self-harm and antidepressant drugs. Investigation of a possible link

BACKGROUND

It is not clear if the frequency of deliberate self-harm (DSH) is the same in patients taking different pharmacological classes of antidepressant drugs.

AIMS

To compare the frequency of DSH in patients who had been prescribed a tricyclic antidepressant (TCA) or a selective serotonin reuptake inhibitor (SSRI) prior to the DSH event.

METHOD

This was a prospective study in 2776 consecutive DSH cases attending an accident and emergency department. The incidence of DSH in TCA-treated cases and SSRI-treated cases is expressed as number of DSH events per 10 000 prescriptions of each antidepressant.

RESULTS

Significantly more DSH events occurred following the prescription of an SSRI than that of a TCA (P<0.001). The occurrence of DSH was highest with fluoxetine and lowest with amitriptyline.

CONCLUSIONS

Merely prescribing safer-in-overdose antidepressants is unlikely to reduce the overall morbidity from DSH.

Effect of hand sanitizer use on elementary school absenteeism

BACKGROUND

Several studies have indicated a connection between handwashing and illness-related absenteeism in school settings. The difficulty of ensuring consistent and effective handwashing among student populations has also been noted. The purpose of this study was to assess the effectiveness of the use of an alcohol gel hand sanitizer in the classroom to help decrease the illness-related absentee rate for elementary school students.

METHODS

This study involved 5 individual school districts, 16 individual schools, and more than 6000 students in Delaware, Ohio, Tennessee, and California. Individual schools in each district were paired into product and control groups. In the product group schools, an alcohol gel hand sanitizer was used by the students and staff when entering and leaving the classroom. Absenteeism due to infection was recorded, and the data were statistically analyzed.

RESULTS

The overall reduction in absenteeism due to infection in the schools included in this study was 19.8% for schools that used an alcohol gel hand sanitizer compared with the control schools (P <.05). Data from the school system with the largest teacher population (n = 246) showed that teacher absenteeism decreased 10.1% (trend) in the schools where sanitizer was used.

CONCLUSION

Elementary school absenteeism due to infection is significantly reduced when an alcohol gel hand sanitizer is used in the classroom as part of a hand hygiene program.

Refractory amiodarone-associated thyrotoxicosis: an indication for thyroidectomy

BACKGROUND

Tasmania is an area of endemic iodine deficiency. Amiodarone is a class III anti-arrhythmic drug that is widely used for the management of ventricular and supraventricular tachydysrhythmias. Individuals from areas of endemic iodine deficiency appear more likely to manifest hyperthyroidism following amiodarone therapy, whereas hypothyroidism is a more frequent complication in iodine-replete communities.

METHODS

Cases series. The clinical and biochemical response to medical and surgical management of five consecutive Tasmanian patients presenting with severe type-II amiodarone-associated thyrotoxicosis was reviewed.

RESULTS

Five patients were identified. Combinations of antithyroid therapy including propylthiouracil, lithium carbonate, dexamethasone and cholestyramine were used. Thyroidectomy was required in two cases (40%) due to severe unremitting thyrotoxicosis despite combined drug regimens. Anaesthesia and total thyroidectomy were undertaken without complication despite the presence of severe hyperthyroidism at the time of surgery. In both cases thyroid histopathology demonstrated degenerative and destructive follicular lesions with multinuclear cell infiltrate and focal fibrosis.

CONCLUSION

Amiodarone-associated thyrotoxicosis may be severe and refractory to medical therapy. Despite the potential risks of anaesthesia associated with uncontrolled thyrotoxicosis, thyroidectomy should be considered in the setting of life-threatening thyrotoxicosis.