Fecal Microbiota Transplantation During Lactation Programs the Metabolism of Adult Wistar Rats in a Sex-specific Way.

BACKGROUND: The intestinal microbiota is involved in many physiological processes. However, the effects of microbiota in metabolic programming still unknow. We evaluated whether the transplantation of fecal microbiota during early life can program health or disease during adulthood in a model of lean and obese male and female Wistar rats. METHODS: Parental obesity were induced using a small litter (SL, 3 pups/dam) model. At 90 d old, normal litter (NL, 9 pups/dam) and SL males and females (parents) from different litters were mated: NL male vs. NL female; SL male vs. SL female. After birth, male and female offspring rats were also standardized in normal litters or small litters . From the 10th until 25th d of life, the NL and SL male and female offspring received via gavage of a solution containing the diluted feces of the opposite dam (fecal microbiota, M) or saline solution (S). At 90 d of age, biometric and biochemical parameters were assessed. RESULTS: NLM male rats transplanted with obese microbiota showed increased body weight, and fat pad deposition, hyperinsulinemia, glucose intolerance and dyslipidemia. SLM male rats transplanted with lean microbiota had decreased retroperitoneal and mesenteric fat, triglycerides and VLDL levels and improvement of glucose tolerance. Despite SLM female rats showed higher visceral fat, microbiota transplantation in female rats caused no changes in these parameters compared with control groups. CONCLUSION: Fecal microbiota transplantation during lactation induces long-term effects on the metabolism of male Wistar rats. However, female rats were resistant to metabolic alterations caused by the treatment.

Neonatal metformin short exposure inhibits male reproductive dysfunction caused by a high-fat diet in adult rats.

Metformin (Met) is widely used to control blood glucose levels and acts on various organs, including reproductive tissues, to improve reproductive and lifespan. This study evaluated whether neonatal Met exposure prevented male reproductive dysfunction caused by being overweight during adulthood. Randomized Wistar rat pups received an intraperitoneal injection from postnatal days (PNDs) 1 to 12of saline (Sal; 0.9% NaCl/day in 2mL/kg) or Met (100 mg/kg/day in 2 mL/kg). From PNDs 60 to 90, the animals received a regular (R; 4.5% fat; Sal R and Met R groups) or a high-fat (HF; 35% fat; Sal HF and Met HF groups) diet. At PND 90, all animals were euthanized to evaluate their biometric and reproductive parameters. The Sal and Met groups with R showed similar body weights, however, the HF diet increased the body weight in both groups. The Sal HF group showed testicular damage regarding in antioxidant status and inflammatory profile in the epididymal cauda. The HF diet reduced Leydig and Sertoli cells numbers, with lower sperm quality. The Met R animals showed positive reproductive programming, due to improved antioxidant defense, inflammatory biomarkers, and sperm morphology. Met HF prevented HF diet damage to reproductive organs and sperm morphology, but not to sperm motility. Early Met exposure positively affected the male reproductive system of adult rats, preventing reproductive HF disorders. STATEMENT OF NOVELTY AND SIGNIFICANCE: Metformin is used to control type 2 diabetes mellitus and can act to improve metabolism and lifespan. Metformin avoidance is recommended during pregnancy, but there is no information regarding its use when breastfeeding. For the first time, we showed in this current study that metformin positively acts in the male reproductive tissues and helps involved in later life. These data showed a better antioxidant defense and anti-inflammatory profile of Metformin animals than Saline animals and might directly improve reproductive organs morphophysiology and sperm morphology. Also, the neonatal Met application programs the male reproduction to counterbalance damages from an obesogenic environment in later life.

Metformin Improves Autonomic Nervous System Imbalance and Metabolic Dysfunction in Monosodium L-Glutamate-Treated Rats.

Metformin is an antidiabetic drug used for the treatment of diabetes and metabolic diseases. Imbalance in the autonomic nervous system (ANS) is associated with metabolic diseases. This study aimed to test whether metformin could improve ANS function in obese rats. Obesity was induced by neonatal treatment with monosodium L-glutamate (MSG). During 21-100 days of age, MSG-rats were treated with metformin 250 mg/kg body weight/day or saline solution. Rats were euthanized to evaluate biometric and biochemical parameters. ANS electrical activity was recorded and analyzed. Metformin normalized the hypervagal response in MSG-rats. Glucose-stimulated insulin secretion in isolated pancreatic islets increased in MSG-rats, while the cholinergic response decreased. Metformin treatment normalized the cholinergic response, which involved mostly the M3 muscarinic acetylcholine receptor (M3 mAChR) in pancreatic beta-cells. Protein expression of M3 mAChRs increased in MSG-obesity rats, while metformin treatment decreased the protein expression by 25%. In conclusion, chronic metformin treatment was effective in normalizing ANS activity and alleviating obesity in MSG-rats.

Early metformin treatment improves pancreatic function and prevents metabolic dysfunction in early overfeeding male rats at adulthood.

NEW FINDINGS: What is the central question of this study? Studies reported the efficacy of metformin as a promising drug for preventing or treating of metabolic diseases. Nutrient stresses during neonatal life increase long-term risk for cardiometabolic diseases. Can early metformin treatment prevent the malprogramming effects of early overfeeding? What is the main finding and its importance? Neonatal metformin treatment prevented early overfeeding-induced metabolic dysfunction in adult rats. Inhibition of early hyperinsulinaemia and adult hyperphagia might be associated with decreased metabolic disease risk in these animals. Therefore, interventions during infant development offer a key area for future research to identify potential strategies to prevent the long-term metabolic diseases. We suggest that metformin is a potential tool for intervention. ABSTRACT: Given the need for studies investigating the possible long-term effects of metformin use at crucial stages of development, and taking into account the concept of metabolic programming, the present work aimed to evaluate whether early metformin treatment might program rats to resist the development of adult metabolic dysfunctions caused by overnutrition during the neonatal suckling phase. Wistar rats raised in small litters (SLs, three pups per dam) and normal litters (NLs, nine pups per dam) were used as models of early overfeeding and normal feeding, respectively. During the first 12 days of suckling, animals from SL and NL groups received metformin, whereas the controls received saline injections. Food intake and body weight were monitored from weaning until 90 days of age, when biometric and biochemical parameters were assessed. The metformin treatment decreased insulin concentrations in pups from SL groups, and as adults, these animals showed improvements in glucose tolerance, insulin sensitivity, body weight gain, white fat pad stores and food intake. Low-glucose insulinotrophic effects were observed in pancreatic islets from both NL and SL groups. These results indicate that early postnatal treatment with metformin inhibits early overfeeding-induced metabolic dysfunctions in adult rats.

Potential attenuation of early-life overfeeding-induced metabolic dysfunction by chronic maternal acetylcholinesterase inhibitor exposure.

Evidence suggests that low concentration perinatal exposure to environmental contaminants, such as organophosphate (OP) is associated with later life insulin resistance and type 2 diabetes. The aim of this work was to investigate whether chronic maternal OP exposure exacerbates metabolic dysfunctions in early-overfed rats. During pregnancy and lactational periods, dams received OP by gavage. To induce neonatal overnutrition at postnatal day 3, pups were standardized to 9 or 3 per nest. At 90-days-old, glucose-insulin homeostasis and insulin release from pancreatic islets were analyzed. While both OP exposure and overfeeding alone did induce diabetogenic phenotypes in adulthood, there was no exacerbation in rats that experienced both. Unexpectedly, the group that experienced both had improved adiposity, metabolic parameters, attenuated insulin release from isolated islets in the presence of glucose and low function of muscarinic acetylcholine receptor M3, as well as an attenuation of beta cell mass hyperplasia. High levels of butyrylcholinesterase and low levels of insulin in milk may contribute to the OP-induced developmental programming. Our study showed that maternal OP exposure may program insulin release as well as endocrine pancreas structure, thus affecting metabolism in adulthood. Our data suggest that while perinatal OP exposure alone increases the risk for later life T2D, it actually reverses many of the programmed metabolic dysfunction that is induced by postnatal overfeeding. These surprising results may suggest that low-dose administration of acetylcholinesterase inhibitors could be of utility in preventing detrimental developmental programming that is caused by early-life overnutrition.

Particulate Matter Exposure During Perinatal Life Results in Impaired Glucose Metabolism in Adult Male Rat Offspring.

BACKGROUND/AIMS: Particulate matter (PM) is an important risk factor for immunological system imbalance due to its small size, which can reach more distal regions of the respiratory tract, independently of its chemical composition. Some studies have suggested that PM exposure is associated with an increased incidence of diabetes, especially in industrialized urban regions. However, studies regarding the effects of PM exposure during perinatal life on glucose metabolism are limited. We tested whether exposure to PM from an urban area with poor air quality during pregnancy and lactation could cause short- and long-term dysfunction in rat offspring. METHODS: Samples of < 10 µm PM were collected in an urban area of Cotonou, Benin (West Africa), and reconstituted in corn oil. Pregnant Wistar rats received 50 µg PM/day by gavage until the end of lactation. After birth, we analyzed the dams' biochemical parameters as well as those of their male offspring at 21 and 90 days of age. RESULTS: The results showed that PM exposure did not lead to several consequences in dams; however, the male offspring of both ages presented an increase of approximately 15% in body weight. Although the blood glucose levels remained unchanged, the insulin levels were increased 2.5- and 2-fold in PM exposure groups of both ages, respectively. HOMA-IR and HOMA-ß were also increased at both ages. We also demonstrated that the number, islet area and insulin immunodensity of pancreatic islets were significantly increased at both ages from PM exposure. CONCLUSION: Our data show that chronic PM exposure by the oral route during perinatal life in rats leads to glucose dyshomeostasis in male offspring both in early and later life. Thus, we suggest that an ambience with poor air quality, mainly where traffic is dense, can contribute to an increase in metabolic disease incidence.

Protein-restriction diet during the suckling phase programs rat metabolism against obesity and insulin resistance exacerbation induced by a high-fat diet in adulthood.

Protein restriction during the suckling phase can malprogram rat offspring to a lean phenotype associated with metabolic dysfunctions later in life. We tested whether protein-caloric restriction during lactation can exacerbate the effect of a high-fat (HF) diet at adulthood. To test this hypothesis, we fed lactating Wistar dams with a low-protein (LP; 4% protein) diet during the first 2 weeks of lactation or a normal-protein (NP; 23% protein) diet throughout lactation. Rat offspring from NP and LP mothers received a normal-protein diet until 60 days old. At this time, a batch of animals from both groups was fed an HF (35% fat) diet, while another received an NF (7% fat) diet. Maternal protein-caloric restriction provoked lower body weight and fat pad stores, hypoinsulinemia, glucose intolerance, higher insulin sensitivity, reduced insulin secretion and altered autonomic nervous system (ANS) function in adult rat offspring. At 90 days old, NP rats fed an HF diet in adulthood displayed obesity, impaired glucose homeostasis and altered insulin secretion and ANS activity. Interestingly, the LP/HF group also presented fat pad and body weight gain, altered glucose homeostasis, hyperleptinemia and impaired insulin secretion but at a smaller magnitude than the NP-HF group. In addition, LP/HF rats displayed elevated insulin sensitivity. We concluded that protein-caloric restriction during the first 14 days of life programs the rat metabolism against obesity and insulin resistance exacerbation induced by an obesogenic HF diet.

Methylglyoxal treatment in lactating mothers leads to type 2 diabetes phenotype in male rat offspring at adulthood.

PURPOSE: Environmental and nutritional disorders during perinatal period cause metabolic dysfunction in the progeny and impair human health. Advanced glycation end products (AGEs) are primarily produced during metabolism of excess blood glucose, which is observed in diabetes. Methylglyoxal (MG) is a precursor for the generation of endogenous AGEs, which disturbs the metabolism. This work aimed to investigate whether the maternal MG treatment during lactation programs the progeny to metabolic dysfunction later in life. METHODS: Female Wistar rats were divided into two groups: control group (C) treated with saline and MG group treated with MG (60 mg/kg/day) by gavage throughout the lactation period. Both mothers and offspring were fed a standard chow. At weaning, breast milk composition was analyzed and mothers euthanized for blood and tissue sample collections. At 90 days of age, offspring were submitted to glucose tolerance test (ivGTT) and euthanized for blood and tissue samples collection. RESULTS: MG mothers showed increase in glucose and fructosamine levels; however, they showed low insulin levels and failure in ß-cell function (p < 0.05). MG mothers also showed dyslipidemia (p < 0.05). Moreover, breast milk had elevated levels of glucose, triglycerides, cholesterol and fructosamine and low insulin (p < 0.05). Interestingly, MG offspring had increased body weight and adipose tissue at adulthood, and they also showed glucose intolerance and failure in ß-cell function (p < 0.05). Besides, MG offspring showed dyslipidemia (p < 0.05) increasing cardiovascular diseases risk. CONCLUSIONS: Maternal MG treatment negatively affects the male rat offspring, leading to type 2 diabetes and dyslipidemia in later life, possibly by changes in breast milk composition.

Maternal low intensity physical exercise prevents obesity in offspring rats exposed to early overnutrition.

Low intensity exercise during pregnancy and lactation may create a protective effect against the development of obesity in offspring exposed to overnutrition in early life. To test these hypotheses, pregnant rats were randomly assigned into 2 groups: Sedentary and Exercised, low intensity, on a rodent treadmill at 30% VO2Max /30-minute/session/3x/week throughout pregnancy and the lactation. Male offspring were raised in small litters (SL, 3 pups/dam) and normal litters (NL, 9 pups/dam) as models of early overnutrition and normal feed, respectively. Exercised mothers showed low mesenteric fat pad stores and fasting glucose and improved glucose-insulin tolerance, VO2max during lactation and sympathetic activity. Moreover, the breast milk contained elevated levels of insulin. In addition, SL of sedentary mothers presented metabolic dysfunction and glucose and insulin intolerance and were hyperglycemic and hyperinsulinemic in adulthood. SL of exercised mothers showed lower fat tissue accretion and improvements in glucose tolerance, insulin sensitivity, insulinemia and glycemia. The results suggest that maternal exercise during the perinatal period can have a possible reprogramming effect to prevent metabolic dysfunction in adult rat offspring exposed to early overnutrition, which may be associated with the improvement in maternal health caused by exercise.

Chronic Glibenclamide Treatment Attenuates Walker-256 Tumour Growth in Prediabetic Obese Rats.

BACKGROUND/AIMS: The sulphonylurea glibenclamide (Gli) is widely used in the treatment of type 2 diabetes. In addition to its antidiabetic effects, low incidences of certain types of cancer have been observed in Gli-treated diabetic patients. However, the mechanisms underlying this observation remain unclear. The aim of the present work was to evaluate whether obese adult rats that were chronically treated with an antidiabetic drug, glibenclamide, exhibit resistance to rodent breast carcinoma growth. METHODS: Neonatal rats were treated with monosodium L-glutamate (MSG) to induce prediabetes. Control and MSG groups were treated with Gli (2 mg/kg body weight/day) from weaning to 100 days old. After Gli treatment, the control and MSG rats were grafted with Walker-256 tumour cells. After 14 days, grafted rats were euthanized, and tumour weight as well as glucose homeostasis were evaluated. RESULTS: Treatment with Gli normalized tissue insulin sensitivity and glucose tolerance, suppressed fasting hyperinsulinaemia, reduced fat tissue accretion in MSG rats, and attenuated tumour growth by 27% in control and MSG rats. CONCLUSIONS: Gli treatment also resulted in a large reduction in the number of PCNA-positive tumour cells. Although treatment did improve the metabolism of pre-diabetic MSG-rats, tumour growth inhibition may be a more direct effect of glibenclamide.

Acephate exposure during a perinatal life program to type 2 diabetes.

Acephate has been used extensively as an insecticide in agriculture. Its downstream sequelae are associated with hyperglycemia, lipid metabolism dysfunction, DNA damage, and cancer, which are rapidly growing epidemics and which lead to increased morbidity and mortality rates and soaring health-care costs. Developing interventions will require a comprehensive understanding of which excess insecticides during perinatal life can cause insulin resistance and type 2 diabetes. A Wistar rat animal model suggests that acephate exposure during pregnancy and lactation causes alterations in maternal glucose metabolism and programs the offspring to be susceptible to type 2 diabetes at adulthood. Therapeutic approaches based on preventive actions to food contaminated with insecticides during pregnancy and lactation could prevent new cases of type 2 diabetes.

Maternal Diet Supplementation with n-6/n-3 Essential Fatty Acids in a 1.2 : 1.0 Ratio Attenuates Metabolic Dysfunction in MSG-Induced Obese Mice.

Essential polyunsaturated fatty acids (PUFAs) prevent cardiometabolic diseases. We aimed to study whether a diet supplemented with a mixture of n-6/n-3 PUFAs, during perinatal life, attenuates outcomes of long-term metabolic dysfunction in prediabetic and obese mice. Seventy-day-old virgin female mice were mated. From the conception day, dams were fed a diet supplemented with sunflower oil and flaxseed powder (containing an n-6/n-3 PUFAs ratio of 1.2 : 1.0) throughout pregnancy and lactation, while control dams received a commercial diet. Newborn mice were treated with monosodium L-glutamate (MSG, 4 mg g-1 body weight per day) for the first 5 days of age. A batch of weaned pups was sacrificed to quantify the brain and pancreas total lipids; another batch were fed a commercial diet until 90 days of age, where glucose homeostasis and glucose-induced insulin secretion (GIIS) as well as retroperitoneal fat and Lee index were assessed. MSG-treated mice developed obesity, glucose intolerance, insulin resistance, pancreatic islet dysfunction, and higher fat stores. Maternal flaxseed diet-supplementation decreased n-6/n-3 PUFAs ratio in the brain and pancreas and blocked glucose intolerance, insulin resistance, GIIS impairment, and obesity development. The n-6/n-3 essential PUFAs in a ratio of 1.2 : 1.0 supplemented in maternal diet during pregnancy and lactation prevent metabolic dysfunction in MSG-obesity model.