Influence of antibiotics given during labour and birth on body mass index z scores in children in the All Our Families pregnancy cohort

BACKGROUND/OBJECTIVES

Little is known about obesity risk associated with intrapartum antibiotic prophylaxis (IAP). Our objective was to determine if maternal antibiotic exposure during birth is associated with child body mass index (BMI) z scores in the first 3 years of life.

METHODS

In 2008 to 2010, 3388 pregnant women were recruited to the All Our Families study. Here, we included women with available data from obstetrical records on antibiotic use during birth (n = 1303) and children with at least one valid BMI z score (final sample n = 1262). The primary outcome was infant BMI z score at 1, 2 and 3 years of age.

RESULTS

IAP occurred in 432 of 1262 women. Children exposed to IAP had significantly higher mean [standard error (SE)] BMI z scores (1.071 [0.087] unit) at 1 year of age compared to non-exposed infants (0.744 [0.064] unit). Although the association was no longer significant after adjustment for confounding factors in the growth trajectory model, IAP resulted in a 0.255 unit increase in BMI z score at 1 year of age. Differences in BMI z score between exposed and non-exposed at baseline (year 1) only remained significant in sensitivity analysis.

CONCLUSION

The potential association between maternal IAP and increased infant BMI z score at 1 year of age should be confirmed in other cohorts and warrants investigation of interventions to mitigate this possible risk.

Contractility of permeabilized rat vastus intermedius muscle fibres following high-fat, high-sucrose diet consumption

Obesity is a worldwide health concern associated with impaired physical function. It is not clear if contractile protein dysfunction contributes to the impairment of muscle function observed with obesity. The purpose of this study was to examine if diet-induced obesity affects contractile function of chemically permeabilized vastus intermedius fibres of male Sprague-Dawley rats expressing fast myosin heavy chain (MHC) IIa or slow MHC I. Rats consumed either a high-fat, high sucrose (HFHS) diet or a standard (CHOW) diet beginning as either weanlings (7-week duration: WEAN7 cohort, or 14-week duration: WEAN14 cohort) or young adults (12-week duration: ADULT12 cohort, 24-week duration: ADULT24 cohort). HFHS-fed rats had higher (P < 0.05) whole-body adiposity (derived from dual-energy X-ray absorptiometry) than CHOW-fed rats in all cohorts. Relative to CHOW diet groups, the HFHS diet was associated with impaired force production in (a) MHC I fibres in the ADULT24 cohort; and (b) MHC IIa fibres in the ADULT12 and ADULT24 cohorts combined. However, the HFHS diet did not significantly affect the Ca2+-sensitivity of force production, unloaded shortening velocity, or ratio of active force to active stiffness in any cohort. We conclude that diet-induced obesity can impair force output of permeabilized muscle fibres of adult rats. Novelty: We assessed contractile function of permeabilized skeletal muscle fibres in a rat model of diet-induced obesity. The high-fat, high-sucrose diet was associated with impaired force output of fibres expressing MHC I or MHC IIa in some cohorts of rats. Other measures of contractile function were not significantly affected by diet.

Concurrent Prebiotic Intake Reverses Insulin Resistance Induced by Early-Life Pulsed Antibiotic in Rats

Pulsed antibiotic treatment (PAT) early in life increases risk of obesity. Prebiotics can reduce fat mass and improve metabolic health. We examined if co-administering prebiotic with PAT reduces obesity risk in rat pups weaned onto a high fat/sucrose diet. Pups were randomized to (1) control [CTR], (2) antibiotic [ABT] (azithromycin), (3) prebiotic [PRE] (10% oligofructose (OFS)), (4) antibiotic + prebiotic [ABT + PRE]. Pulses of antibiotics/prebiotics were administered at d19-21, d28-30 and d37-39. Male and female rats given antibiotics (ABT) had higher body weight than all other groups at 10 wk of age. The PAT phenotype was stronger in ABT males than females, where increased fat mass, hyperinsulinemia and insulin resistance were present and all reversible with prebiotics. Reduced hypothalamic and hepatic expression of insulin receptor substrates and ileal tight junction proteins was seen in males only, explaining their greater insulin resistance. In females, insulin resistance was improved with prebiotics and normalized to lean control. ABT reduced Lactobacillaceae and increased Bacteroidaceae in both sexes. Using a therapeutic dose of an antibiotic commonly used for acute infection in children, PAT increased body weight and impaired insulin production and insulin sensitivity. The effects were reversed with prebiotic co-administration in a sex-specific manner.

Maternal low-dose aspartame and stevia consumption with an obesogenic diet alters metabolism, gut microbiota and mesolimbic reward system in rat dams and their offspring

OBJECTIVE

We examined the impact of maternal low-dose aspartame and stevia consumption on adiposity, glucose tolerance, gut microbiota and mesolimbic pathway in obese dams and their offspring.

DESIGN

Following obesity induction, female Sprague-Dawley rats were allocated during pregnancy and lactation to: (1) high fat/sucrose diet (HFS) +water (obese-WTR); (2) HFS +aspartame (obese-APM; 5-7 mg/kg/day); (3) HFS +stevia (obese-STV; 2-3 mg/kg/day). Offspring were weaned onto control diet and water and followed until 18 weeks. Gut microbiota and metabolic outcomes were measured in dams and offspring. Cecal matter from offspring at weaning was used for faecal microbiota transplant (FMT) into germ-free (GF) mice.

RESULTS

Maternal APM and STV intake with a HFS diet increased body fat in offspring at weaning and body weight long-term with APM. Maternal APM/HFS consumption impaired glucose tolerance in male offspring at age 8 weeks and both APM and STV altered faecal microbiota in dams and offspring. Maternal obesity/HFS diet affected offspring adiposity and glucose tolerance more so than maternal LCS consumption at age 12 and 18 weeks. APM and STV altered expression of genes in the mesolimbic reward system that may promote consumption of a palatable diet. GF mice receiving an FMT from obese-APM and obese-STV offspring had greater weight gain and body fat and impaired glucose tolerance compared with obese-WTR.

CONCLUSION

Maternal low-calorie sweetener consumption alongside HFS may disrupt weight regulation, glucose control and gut microbiota in dams and their offspring most notably in early life despite no direct low-calorie sweetener consumption by offspring.

Prebiotic Oligofructose Prevents Antibiotic-Induced Obesity Risk and Improves Metabolic and Gut Microbiota Profiles in Rat Dams and Offspring

SCOPE

Antibiotics in early life disrupt microbiota and increase obesity risk. Dietary agents such as prebiotics may reduce obesity risk. The authors examine how antibiotics administered with/without prebiotic oligofructose, alter metabolic and microbial outcomes in pregnant rats and their offspring.

METHODS AND RESULTS

Pregnant rats are randomized to: 1) Control, 2) Antibiotic (ABT), 3) Prebiotic (PRE), 4) Antibiotic+Prebiotic (ABT+PRE) during the 3rd week of pregnancy and lactation. Offspring were fed a high fat/high sucrose (HFS) diet from 9-17 weeks of age to unmask obesity risk. ABT dams had higher body weight, body fat and leptin during lactation than all other groups. Prebiotics attenuate these outcomes and increase cecal Bifidobacterium. ABT offspring have higher body weight, fat mass, and liver triglycerides after HFS diet, with a stronger phenotype in males; prebiotics attenuate these. At weaning, male ABT offspring have lower Lactobacillus while PRE and ABT+PRE offspring had higher Bifidobacterium and Collinsella. Fecal microbiota transfer of adult offspring cecal matter could not reliably transfer the obese ABT phenotype.

CONCLUSIONS

Antibiotic use during pregnancy/lactation increases adiposity and impairs post-partum weight loss in dams. Co-administering prebiotics with antibiotics in rat dams prevented obesity risk in offspring and is associated with altered gut microbiota.

Human Milk Oligosaccharide Supplementation Affects Intestinal Barrier Function and Microbial Composition in the Gastrointestinal Tract of Young Sprague Dawley Rats

Human milk oligosaccharides (HMOs) are chief maternal milk constituents that feed the intestinal microbiota and drive maturation of the infant gut. Our objective was to determine whether supplementing individual HMOs to a weanling diet alters growth and gut health in rats. Healthy three-week-old Sprague Dawley rat pups were randomized to control, 2'-O-fucosyllactose (2'FL)- and 3'sialyllactose (3'SL)-fortified diets alone or in combination at physiological doses for eight weeks. Body composition, intestinal permeability, serum cytokines, fecal microbiota composition, and messenger RNA (mRNA) expression in the gastrointestinal tract were assessed. Males fed a control diet were 10% heavier and displayed elevated interleukin (IL-18) (p = 0.01) in serum compared to all HMO-fortified groups at week 11. No differences in body composition were detected between groups. In females, HMOs did not affect body weight but 2'FL + 3'SL significantly increased cecum weight. All female HMO-fortified groups displayed significant reductions in intestinal permeability compared to controls (p = 0.02). All HMO-fortified diets altered gut microbiota composition and mRNA expression in the gastrointestinal tract, albeit differently according to sex. Supplementation with a fraction of the HMOs found in breast milk has a complex sex-dependent risk/benefit profile. Further long-term investigation of gut microbial profiles and supplementation with other HMOs during early development is warranted.

Gut microbiota and obesity: Impact of antibiotics and prebiotics and potential for musculoskeletal health

Obesity is a complex disease with multiple contributing factors. One of the most intensely studied factors during the past decade has been the gut microbiota, which is the community of all microbes in the intestinal tract. The gut microbiota, via energy extraction, inflammation, and other actions, is now recognized as an important player in the pathogenesis of obesity. Dysbiosis, or an imbalance in the microbial community, can initiate a cascade of metabolic disturbances in the host. Early life is a particularly important period for the development of the gut microbiota, and perturbations such as with antibiotic exposure can have long-lasting consequences for host health. In early life and throughout the life span, diet is one of the most important factors that shape the gut microbiota. Although diets high in fat and sugar have been shown to contribute to dysbiosis and disease, dietary fiber is recognized as an important fermentative fuel for the gut microbiota and results in the production of short-chain fatty acids that can act as signaling molecules in the host. One particular type of fiber, prebiotic fiber, contributes to changes in the gut microbiota, the most notable of which is an increase in the abundance of Bifidobacterium. This review highlights our current understanding of the role of gut microbiota in obesity development and the ways in which manipulating the microbiota through dietary means, specifically prebiotics, could contribute to improved health in the host, including musculoskeletal health.

Low-Dose Stevia (Rebaudioside A) Consumption Perturbs Gut Microbiota and the Mesolimbic Dopamine Reward System

Stevia is a natural low-calorie sweetener that is growing in popularity in food and beverage products. Despite its widespread use, little is understood of its impact on the gut microbiota, an important environmental factor that can mediate metabolism and subsequent obesity and disease risk. Furthermore, given previous reports of dysbiosis with some artificial low-calorie sweeteners, we wanted to understand whether prebiotic consumption could rescue potential stevia-mediated changes in gut microbiota. Three-week old male Sprague-Dawley rats were randomized to consume: (1) Water (CTR); (2) Rebaudioside A (STV); (3) prebiotic (PRE); (4) Rebaudioside A + prebiotic (SP) (n = 8/group) for 9 weeks. Rebaudioside was added to drinking water and prebiotic oligofructose-enriched inulin added to control diet (10%). Body weight and feces were collected weekly and food and fluid intake biweekly. Oral glucose and insulin tolerance tests, gut permeability tests, dual X-ray absorptiometry, and tissue harvest were performed at age 12 weeks. Rebaudioside A consumption alone did not alter weight gain or glucose tolerance compared to CTR. Rebaudioside A did, however, alter gut microbiota composition and reduce nucleus accumbens tyrosine hydroxylase and dopamine transporter mRNA levels compared to CTR. Prebiotic animals, alone or with Rebaudioside A, had reduced fat mass, food intake, and gut permeability and cecal SCFA concentration. Adding Rebaudioside A did not interfere with the benefits of the prebiotic except for a significant reduction in cecal weight. Long-term low-dose Rebaudioside A consumption had little effect on glucose metabolism and weight gain; however, its impact on gut microbial taxa should be further examined in populations exhibiting dysbiosis such as obesity.

Impact of Food Ingredients (Aspartame, Stevia, Prebiotic Oligofructose) on Fertility and Reproductive Outcomes in Obese Rats

OBJECTIVE

This study aimed to investigate the interaction between obesity, low-calorie sweeteners, and prebiotic oligofructose on reproductive parameters in rats.

METHODS

Data were derived from two separate studies of female Sprague-Dawley rats with (1) Lean (n = 24), (2) Obese (n = 27), (3) Obese+Aspartame (n = 14), (4) Obese+Stevia (n = 15), and (5) Obese+Prebiotic (n = 15) groups. Obesity was induced with a high-fat/high-sucrose diet prior to pregnancy. In one study, human-approved doses of aspartame (5-7 mg/kg/d) and stevia (2-3 mg/kg/d) in drinking water were examined, and in the second, 10% prebiotics (oligofructose) in the diet was examined. Reproductive parameters, including fertility, pregnancy, and delivery indexes, were analyzed.

RESULTS

Obesity significantly reduced pregnancy index in Obese dams (60.7% successful pregnancies) compared with lean (100%). Obesity also reduced the number of pups born alive and pup survival percentage compared with those of Lean dams (P < 0.001). Only 53.3% of rats were able to conceive in the Obese+Stevia group, but if rats did become pregnant, they had 100% pregnancy and delivery index. While prebiotic administration rescued the pregnancy index, it could not remediate pup survival percentage (P = 0.025) in Obese dams.

CONCLUSIONS

Both obesity status and dietary ingredients affect the ability to conceive. Future rigorously controlled studies designed to examine reproductive outcomes in depth are needed to confirm these findings.

Oligofructose decreases serum lipopolysaccharide and plasminogen activator inhibitor-1 in adults with overweight/obesity

OBJECTIVE

To determine the effect of prebiotic supplementation on metabolic endotoxemia and systemic inflammation in adults with overweight and obesity.

METHODS

Samples from a previously conducted randomized, double-blind, placebo-controlled trial were used for analysis. Participants were randomized to 21 g of oligofructose (n = 20; BMI 30.4 kg/m² ) or a maltodextrin placebo (n = 17; BMI 29.5 kg/m² ) for 12 weeks. A total of 37 participants had samples available for the current analysis. Resistin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and macrophage chemoattractant protein-1 (MCP-1) were quantified using MILLIPLEX® assays. Lipopolysaccharide (LPS) was measured using PyroGene™ Recombinant Factor C Assay.

RESULTS

Plasma LPS concentrations were reduced by 40% in the oligofructose group over 12 weeks compared to a 48% increase in the placebo group (P = 0.04). PAI-1, a risk factor for thrombosis, was reduced to a greater extent in the oligofructose group (-17.3 ± 2.6 ng/ml) compared to the placebo group (-9.7 ± 1.8 ng/ml; P = 0.03). Oligofructose did not affect IL-6, TNF-α, MCP-1, adiponectin, or resistin.

CONCLUSIONS

Oligofructose reduces metabolic endotoxemia and PAI-1. Incorporating prebiotics into the diet through supplements or functional foods may help mitigate some markers of obesity-associated inflammation.

High density lipoprotein and metabolic disease: Potential benefits of restoring its functional properties

Background

High density lipoproteins (HDLs) are thought to be atheroprotective and to reduce the risk of cardiovascular disease (CVD). Besides their antioxidant, antithrombotic, anti-inflammatory, anti-apoptotic properties in the vasculature, HDLs also improve glucose metabolism in skeletal muscle.

Scope of the review

Herein, we review the functional role of HDLs to improve metabolic disorders, especially those involving insulin resistance and to induce regression of CVD with a particular focus on current pharmacological treatment options as well as lifestyle interventions, particularly exercise.

Major conclusions

Functional properties of HDLs continue to be considered important mediators to reverse metabolic dysfunction and to regress atherosclerotic cardiovascular disease. Lifestyle changes are often recommended to reduce the risk of CVD, with exercise being one of the most important of these. Understanding how exercise improves HDL function will likely lead to new approaches to battle the expanding burden of obesity and the metabolic syndrome.