Lactational High-Fat Diet Exposure Programs Metabolic Inflammation and Bone Marrow Adiposity in Male Offspring

The Influence of Maternal High Fat Diet During Lactation on Offspring Hematopoietic Priming

Obesity and metabolic diseases are rising among women of reproductive age, increasing offspring metabolic risk. Maternal nutritional interventions during lactation present an opportunity to modify offspring outcomes. We previously demonstrated in mice that adult male offspring have metabolic impairments and increased adipose tissue macrophages (ATM) when dams are fed high fat diet (HFD) during the postnatal lactation window (HFD PN). We sought to understand the effect of HFD during lactation on early-life inflammation. HFD PN offspring were evaluated at postnatal day 16 to 19 for tissue weight and gene expression. Profiling of adipose tissue and bone marrow immune cells was conducted through lipidomics, in vitro myeloid colony forming unit assays, and flow cytometry. HFD PN mice had more visceral gonadal white adipose tissue (GWAT) and subcutaneous fat. Adipose tissue RNA sequencing demonstrated enrichment of inflammation, chemotaxis, and fatty acid metabolism and concordant changes in GWAT lipidomics. Bone marrow (BM) of both HFD PN male and female offspring had increased monocytes (CD45+Ly6G-CD11b+CD115+) and B cells (CD45+Ly6G-CD11b-CD19+). Similarly, serum from HFD PN offspring enhanced in vitro BM myeloid colonies in a toll-like receptor 4-dependent manner. We identified that male HFD PN offspring had increased GWAT pro-inflammatory CD11c+ ATMs (CD45+CD64+). Maternal exposure to HFD alters milk lipids enhancing adiposity and myeloid inflammation even in early life. Future studies are needed to understand the mechanisms driving this pro-inflammatory state of both BM and ATMs, the causes of the sexually dimorphic phenotypes, and the feasibility of intervening in this window to improve metabolic health.

White adipose tissue undergoes browning during preweaning period in association with microbiota formation in mice

Beige adipocytes are transiently induced during early postnatal period in mice. Previous studies have suggested that, unlike in adults, the induction is independent of the sympathetic nerve activity; however, the mechanism is yet unknown. Here, we showed that beige adipocytes are induced during the preweaning period in association with the formation of microbiota in mice. Alteration of gut microbiota composition in preweaning mice by maternal treatment with antibiotics or high-fat diet feeding substantially suppressed WAT browning. The suppression was also found in pups transplanted cecal microbiota from pups of high-fat diet-fed dams. These treatments reduced the hepatic expression of genes involved in bile acid synthesis and the serum bile acids level. The abundance of Porphyromonadaceae and Ruminococcaceae in microbiota showed a positive and negative correlation with the induction of beige adipocytes, respectively. This finding may provide comprehensive understanding of the association between gut microbiota and adipose tissue development in the neonatal period.

Non-Alcoholic Fatty Liver Disease and Bone Tissue Metabolism: Current Findings and Future Perspectives

Non-alcoholic fatty liver disease (NAFLD) is reaching epidemic proportions worldwide. Moreover, the prevalence of this liver disease is expected to increase rapidly in the near future, aligning with the rise in obesity and the aging of the population. The pathogenesis of NAFLD is considered to be complex and to include the interaction between genetic, metabolic, inflammatory, and environmental factors. It is now well documented that NAFLD is linked to the other conditions common to insulin resistance, such as abnormal lipid levels, metabolic syndrome, and type 2 diabetes mellitus. Additionally, it is considered that the insulin resistance may be one of the main mechanisms determining the disturbances in both bone tissue metabolism and skeletal muscles quality and functions in patients with NAFLD. To date, the association between NAFLD and osteoporosis has been described in several studies, though it worth noting that most of them included postmenopausal women or elderly patients and originated from Asia. However, taking into account the health and economic burdens of NAFLD, and the increasing prevalence of obesity in children and adolescents worldwide, further investigation of the relationship between osteopenia, osteoporosis and sarcopenia in NAFLD, including in young and middle-aged patients, is of great importance. In addition, this will help to justify active screening and surveillance of osteopenia and osteoporosis in patients with NAFLD. In this review, we will discuss various pathophysiological mechanisms and possible biologically active molecules that may interplay between NAFLD and bone tissue metabolism.

Mechanisms of Maternal Diet-Induced Obesity Affecting the Offspring Brain and Development of Affective Disorders

Depression and metabolic disease are common disorders that share a bidirectional relationship and continue to increase in prevalence. Maternal diet and maternal behaviour both profoundly influence the developmental trajectory of offspring during the perinatal period. At an epidemiological level, both maternal depression and obesity during pregnancy have been shown to increase the risk of neuropsychiatric disease in the subsequent generation. Considerable progress has been made to understand the mechanisms by which maternal obesity disrupts the developing offspring gut-brain axis, priming offspring for the development of affective disorders. This review outlines such mechanisms in detail, including altered maternal care, the maternal microbiome, inflammation, breast milk composition, and maternal and placental metabolites. Subsequently, offspring may be prone to developing gut-brain interaction disorders with concomitant changes to brain energy metabolism, neurotransmission, and behaviour, alongside gut dysbiosis. The gut microbiome may act as a key modifiable, and therefore treatable, feature of the relationship between maternal obesity and the offspring brain function. Further studies examining the relationship between maternal nutrition, the maternal microbiome and metabolites, and offspring neurodevelopment are warranted to identify novel therapeutic targets.

Energy Balance and Bone Health: a Nutrient Availability Perspective

PURPOSE OF REVIEW

Obesity is highly prevalent and is associated with bone fragility and fracture. The changing nutrient availability to bone in obesity is an important facet of bone health. The goal of this article is to summarize current knowledge on the effects of carbohydrate and dietary fat availability on bone, particularly in the context of other tissues.

RECENT FINDINGS

The skeleton is a primary site for fatty acid and glucose uptake. The trafficking of carbohydrates and fats into tissues changes with weight loss and periods of weight gain. Exercise acutely influences nutrient uptake into bone and may affect nutrient partitioning to bone. Bone cells secrete hormones that signal to the brain and other tissues information about its energetic state, which may alter whole-body nutrient trafficking. There is a critical need for studies to address the changes that metabolic perturbations have on nutrient availability in bone.

The Effect of BMI on Blood Lipids and Dyslipidemia in Lactating Women

Background: This study aimed to explore the correlation between body mass index (BMI) and dyslipidemia and the optimal cut-off point for BMI to distinguish the risk of dyslipidemia in lactating women. Methods: A total of 2295 lactating women subjects were included in this study, all within 2 years postpartum. All samples were from “China Children and Lactating Mothers Nutritional Health Surveillance (2016−2017)”. BMI, blood lipids, demographic information, lifestyle habits, and other serum indicators were obtained in this survey. Generalized linear model, logistic regression, restricted cubic spline (RCS) and ROC curve analysis were used to evaluate the relationship among BMI, blood lipids, and dyslipidemia. Results: BMI in lactating women was positively correlated with total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), but negatively correlated with high-density lipoproteincholesterol (HDL-C) (p < 0.05). Higher BMI in lactating women was associated with higher ORs of dyslipidemia (hypercholesterolemia, hypertriglyceridemia, high-LDL-cholesterolemia, low HDL-cholesterolemia) (p < 0.05). These associations were stable across age groups, breastfeeding child age (months), parity, physical activity level, fasting plasma glucose (FPG), and hemoglobin. These factors did not interact with this relationship (p > 0.05). The optimal cut-off point for BMI was 24.85 kg/m2 determined by using ROC analysis, which can distinguish the risk of dyslipidemia. Conclusions: BMI was positively correlated with risk of dyslipidemia. Maintaining an ideal weight may prevent dyslipidemia in lactating women, and BMI is recommended to be controlled below 24.85 kg/m2.

Maternal Treatment with Metformin Persistently Ameliorates High-Fat Diet-Induced Metabolic Symptoms and Modulates Gut Microbiota in Rat Offspring

A maternal high-fat (HF) diet has long-term deleterious effect on offspring. This study aims to evaluate whether maternal metformin (MT) treatment ameliorates the adverse effects of maternal HF diet on offspring and the role of gut microbiota in it. Pregnant Sprague-Dawley rats were randomly assigned to a HF diet (60% fat) or a standard chow diet (11.8% fat) group, and part of the HF diet group rats were co-treated with MT via drinking water (300 mg/kg/day), resulting in three groups according to maternal diet and MT treatment during gestation and lactation. All offspring were weaned on a chow diet. A maternal HF diet showed a significant deleterious effect on offspring’s metabolic phenotype and induced colonic inflammation and gut-barrier disruption through the reshaped gut microbiota. The daily oral administration of MT to HF-fed dams during gestation and lactation reversed the dysbiosis of gut microbiota in both dams and adult offspring. The hypothalamic TGR5 expression and plasma bile acids composition in adult male offspring was restored by maternal MT treatment, which could regulate hypothalamic appetite-related peptides expression and alleviate inflammation, thereby improving male offspring’s metabolic phenotype. The present study indicates that targeting the gut–brain axis through the mother may be an effective strategy to control the metabolic phenotype of offspring.

Short Term Changes in Dietary Fat Content and Metformin Treatment During Lactation Impact Milk Composition and Mammary Gland Morphology

Maternal health and diet can have important consequences for offspring nutrition and metabolic health. During lactation, signals are communicated from the mother to the infant through milk via macronutrients, hormones, and bioactive molecules. In this study we designed experiments to probe the mother-milk-infant triad in the condition of normal maternal health and upon exposure to high fat diet (HFD) with or without concurrent metformin exposure. We examined maternal characteristics, milk composition and offspring metabolic parameters on postnatal day 16, prior to offspring weaning. We found that lactational HFD increased maternal adipose tissue weight, mammary gland adipocyte size, and altered milk lipid composition causing a higher amount of omega-6 (n6) long chain fatty acids and lower omega-3 (n3). Offspring of HFD dams were heavier with more body fat during suckling. Metformin (Met) exposure decreased maternal blood glucose and several milk amino acids. Offspring of met dams were smaller during suckling. Gene expression in the lactating mammary glands was impacted to a greater extent by metformin than HFD, but both metformin and HFD altered genes related to muscle contraction, indicating that these genes may be more susceptible to lactational stressors. Our study demonstrates the impact of common maternal exposures during lactation on milk composition, mammary gland function and offspring growth with metformin having little capacity to rescue the offspring from the effects of a maternal HFD during lactation.

The Impact of Diet on Bone and Fracture Risk in Diabetes

PURPOSE OF REVIEW

The purpose of this review is to summarize the recently published scientific evidence on the effects of diet on diabetes and skeletal health.

RECENT FINDINGS

The impact of diet on overall health has been a growing topic of interest among researchers. An inappropriate eating habit is a relatively modified risk factor for diabetes in adults. Parallel with the significant increase in the incidence of diabetes mellitus worldwide, many studies have shown the benefits of lifestyle modifications, including diet and exercise for people with, or at risk of developing, diabetes. In the last years, accumulating evidence suggests that diabetes is a risk factor for bone fragility. As lifestyle intervention represents an effective option for diabetes management and treatment, there is potential for an effect on bone health. Healthy lifestyle is critical to prevent bone fragility. However, more studies are needed to fully understand the impact of diet and weight loss on fracture risk in diabetics.

Lactational High Fat Diet in Mice Causes Insulin Resistance and NAFLD in Male Offspring Which Is Partially Rescued by Maternal Metformin Treatment

Maternal metabolic disease and diet during pregnancy and lactation have important implications for the programming of offspring metabolic disease. In addition, high-fat diets during pregnancy and lactation can predispose the offspring to non-alcoholic fatty liver disease (NAFLD), a rising health threat in the U.S. We developed a model of maternal high-fat feeding exclusively during the lactation period. We previously showed that offspring from dams, given lactational high-fat diet (HFD), are predisposed to obesity, glucose intolerance, and inflammation. In separate experiments, we also showed that lactational metformin treatment can decrease offspring metabolic risk. The purpose of these studies was to understand the programming implications of lactational HFD on offspring metabolic liver disease risk. Dams were fed a 60% lard-based HFD from the day of delivery through the 21-day lactation period. A subset of dams was also given metformin as a co-treatment. Starting at weaning, the offspring were fed normal fat diet until 3 months of age; at which point, a subset was challenged with an additional HFD stressor. Lactational HFD led male offspring to develop hepatic insulin resistance. The post-weaning HFD challenge led male offspring to progress to NAFLD with more severe outcomes in the lactational HFD-challenged offspring. Co-administration of metformin to lactating dams on HFD partially rescued the offspring liver metabolic defects in males. Lactational HFD or post-weaning HFD had no impact on female offspring who maintained a normal insulin sensitivity and liver phenotype. These findings indicate that HFD, during the lactation period, programs the adult offspring to NAFLD risk in a sexually dimorphic manner. In addition, early life intervention with metformin via maternal exposure may prevent some of the liver programming caused by maternal HFD.

Developmental Timing of High-Fat Diet Exposure Impacts Glucose Homeostasis in Mice in a Sex-Specific Manner

We previously demonstrated that male, but not female, Swiss Webster mice are susceptible to diabetes, with incidence increased by early overnutrition and high-fat diet (HFD). In this study, we investigated how HFD in Swiss Webster males and females during preweaning, peripubertal, and postpubertal periods alters glucose homeostasis and diabetes susceptibility. In males, HFD throughout life resulted in the highest diabetes incidence. Notably, switching to chow postpuberty was protective against diabetes relative to switching to chow at weaning, despite the longer period of HFD exposure. Similarly, HFD throughout life in males resulted in less liver steatosis relative to mice with shorter duration of postpubertal HFD. Thus, HFD timing relative to weaning and puberty, not simply exposure length, contributes to metabolic outcomes. Females were protected from hyperglycemia regardless of length or timing of HFD. However, postpubertal HFD resulted in a high degree of hepatic steatosis and adipose fibrosis, but glucose regulation and insulin sensitivity remained unchanged. Interestingly, peri-insulitis was observed in the majority of females but was not correlated with impaired glucose regulation. Our findings reveal critical periods of HFD-induced glucose dysregulation with striking sex differences in Swiss Webster mice, highlighting the importance of careful consideration of HFD timing relative to critical developmental periods.

The Impact of Maternal High-Fat Diet on Bone Microarchitecture in Offspring

The incidence of obesity in women of reproductive age has significantly increased over the past 100 years. There is a well-established connection between maternal obesity during pregnancy and an increased risk of developing non-communicable cardiometabolic diseases in her offspring. This mini-review focuses on evidence examining the effect of maternal high-fat diet (HFD) on skeletal development and bone health in later life in offspring. The majority of rodent studies indicate that maternal HFD generally negatively affects both embryonic bone development and bone volume in adult animals. Details surrounding the mechanisms of action that drive changes in the skeleton in offspring remain unclear, although numerous studies suggest that some effects are sex-specific. Human studies in this area are limited but also suggest that HFD during pregnancy may impair bone formation and increase fracture risk during childhood. Given the consequences of low bone mass and deranged bone microarchitecture for offspring, advances in our understanding of the developmental origins of bone health is critical in the battle against osteoporosis.

Milk Polar Lipids Supplementation to Obese Rats During Pregnancy and Lactation Benefited Skeletal Outcomes of Male Offspring

SCOPE

Dietary intervention to obese dams during pregnancy and lactation period provides avenues for improving metabolic profiles of the offspring. In the current study, the effects of polar lipids-enriched milk fat globule membrane (MFGM-PL) supplementation to obese dams during pregnancy and lactation on the skeletal outcomes of male offspring are investigated.

METHODS AND RESULTS

MFGM-PL is supplemented to obese rats induced by high-fat diet during pregnancy and lactation at a dose of 400 mg kg-1 body weight. Results show that maternal MFGM-PL supplementation significantly ameliorates the stunted skeletal growth of male offspring at weaning. In adulthood offspring, maternal MFGM-PL supplementation protects against high-fat diet (HFD)-induced bone microstructure degeneration and bone marrow adipocyte accumulation. Further investigation shows that maternal supplementation of MFGM-PL significantly ameliorates insulin resistance and increases the mRNA expression of growth hormone releasing hormone (GHRH) in the hypothalamus of HFD offspring. The growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis is subsequently enhanced in MFGM-PL + HFD offspring, contributing to the beneficial skeletal outcomes.

CONCLUSION

The findings suggest that maternal MFGM-PL supplementation of HFD dam during pregnancy and lactation shows desirable effects on fetal skeletal development, with lasting beneficial programming impacts on skeletal outcomes of offspring.

Molecular Interactions between Dietary Lipids and Bone Tissue during Aging

Age-related bone disorders such as osteoporosis or osteoarthritis are a major public health problem due to the functional disability for millions of people worldwide. Furthermore, fractures are associated with a higher degree of morbidity and mortality in the long term, which generates greater financial and health costs. As the world population becomes older, the incidence of this type of disease increases and this effect seems notably greater in those countries that present a more westernized lifestyle. Thus, increased efforts are directed toward reducing risks that need to focus not only on the prevention of bone diseases, but also on the treatment of persons already afflicted. Evidence is accumulating that dietary lipids play an important role in bone health which results relevant to develop effective interventions for prevent bone diseases or alterations, especially in the elderly segment of the population. This review focuses on evidence about the effects of dietary lipids on bone health and describes possible mechanisms to explain how lipids act on bone metabolism during aging. Little work, however, has been accomplished in humans, so this is a challenge for future research.

Temporal metabolic and transcriptomic characteristics crossing islets and liver reveal dynamic pathophysiology in diet-induced diabetes

To investigate the molecular mechanisms underlying islet dysfunction and insulin resistance in diet-induced diabetes, we conducted temporal RNA sequencing of tissues responsible for insulin secretion (islets) and action (liver) every 4 weeks in mice on high-fat (HFD) or chow diet for 24 weeks, linking to longitudinal profile of metabolic characteristics. The diverse responses of α, β, and δ cells to glucose and palmitate indicated HFD-induced dynamic deterioration of islet function from dysregulation to failure. Insulin resistance developed with variable time course in different tissues. Weighted gene co-expression network analysis and Ingenuity Pathway Analysis implicated islets and liver jointly programmed β-cell compensatory adaption via cell proliferation at early phase and irreversible islet dysfunction by inappropriate immune response at later stage, and identified interconnected molecules including growth differentiation factor 15. Frequencies of T cell subpopulation showed an early decrement in Tregs followed by increases in Th1 and Th17 cells during progression to diabetes.

Breastfeeding Contributes to Physiological Immune Programming in the Newborn

The first 1,000 days in the life of a human being are a vulnerable stage where early stimuli may program adverse health outcomes in future life. Proper maternal nutrition before and during pregnancy modulates the development of the fetus, a physiological process known as fetal programming. Defective programming promotes non-communicable chronic diseases in the newborn which might be prevented by postnatal interventions such as breastfeeding. Breast milk provides distinct bioactive molecules that contribute to immune maturation, organ development, and healthy microbial gut colonization, and also secures a proper immunological response that protects against infection and inflammation in the newborn. The gut microbiome provides the most critical immune microbial stimulation in the newborn in early life, allowing a well-trained immune system and efficient metabolic settings in healthy subjects. Conversely, negative fetal programming by exposing mothers to diets rich in fat and sugar has profound effects on breast milk composition and alters the immune profiles in the newborn. At this new stage, newborns become vulnerable to immune compromise, favoring susceptibility to defective microbial gut colonization and immune response. This review will focus on the importance of breastfeeding and its immunological biocomponents that allow physiological immune programming in the newborn. We will highlight the importance of immunological settings by breastfeeding, allowing proper microbial gut colonization in the newborn as a window of opportunity to secure effective immunological response.

The impact of a high fat diet on bones: potential mechanisms

High-fat diet led to bone loss via gut microbiota and fatty acid imbalances, immune disorder and adipose tissue accumulation inside and outside the bone marrow.

Lactational metformin exposure programs offspring white adipose tissue glucose homeostasis and resilience to metabolic stress in a sex-dependent manner

We previously demonstrated that exposing mouse dams to metformin during gestation results in increased beta-cell mass at birth and increased beta-cell insulin secretion in adult male offspring. Given these favorable changes after a gestational maternal metformin exposure, we wanted to understand the long-term metabolic impact on offspring after exposing dams to metformin during the postnatal window. The newborn period provides a feasible clinical window for intervention and is important for beta-cell proliferation and metabolic tissue development. Using a C57BL/6 model, we administered metformin to dams from the day of birth to postnatal day 21. We monitored maternal health and offspring growth during the lactation window, as well as adult glucose homeostasis through in vivo testing. At necropsy we assessed pancreas and adipocyte morphology using histological and immunofluorescent staining techniques. We found that metformin exposure programmed male and female offspring to be leaner with a higher proportion of small adipocytes in the gonadal white adipose tissue (GWAT). Male, but not female, offspring had an improvement in glucose tolerance as young adults concordant with a mild increase in insulin secretion in response to glucose in vivo. These data demonstrate long-term metabolic programming of offspring associated with maternal exposure to metformin during lactation.

Microbial Reconstitution Reverses Early Female Puberty Induced by Maternal High-fat Diet During Lactation

Recent work shows that gut microbial dysbiosis contributes to the risk of obesity in children whose mothers consume a high-fat diet (HFD) during both gestation and lactation or during gestation alone. Obesity predisposes children to developing precocious puberty. However, to date, no study has examined how maternal HFD (MHFD) during lactation regulates the gut microbiota (GM), pubertal timing, and fertility of offspring. Here, we found that MHFD during lactation markedly altered the GM of offspring. The pups developed juvenile obesity, early puberty, irregular estrous cycles, and signs of disrupted glucose metabolism. Remarkably, permitting coprophagia between MHFD and maternal normal chow offspring successfully reversed the GM changes as well as early puberty and insulin insensitivity. Our data suggest that microbial reconstitution may prevent or treat early puberty associated with insulin resistance.