Effects of paternal obesity on growth and adiposity of male rat offspring

Preconceptional paternal caloric restriction of high-fat diet-induced obesity in Wistar rats dysregulates the metabolism of their offspring via AMPK/SIRT1 pathway

BACKGROUND

Obesity is a metabolic syndrome where allelic and environmental variations together determine the susceptibility of an individual to the disease. Caloric restriction (CR) is a nutritional dietary strategy recognized to be beneficial as a weight loss regime in obese individuals. Preconceptional parental CR is proven to have detrimental effects on the health and development of their offspring. As yet studies on maternal CR effect on their offspring are well established but paternal CR studies are not progressing. In current study, the impact of different paternal CR regimes in diet-induced obese male Wistar rats (WNIN), on their offspring concerning metabolic syndrome are addressed.

METHODS

High-fat diet-induced obese male Wistar rats were subjected to caloric restriction of 50% (HFCR-I) and 40% (HFCR-II) and then they were mated with normal females. The male parent's reproductive function was assessed by sperm parameters and their DNMT's mRNA expression levels were also examined. The offspring's metabolic function was assessed by physiological, biochemical and molecular parameters.

RESULTS

The HFCR-I male parents have shown reduced body weights, compromised male fertility and reduced DNA methylation activity. Further, the HFCR-I offspring showed attenuation of the AMPK/SIRT1 pathway, which is associated with the progression of proinflammatory status and oxidative stress. In line, the HFCR-I offspring also developed altered glucose and lipid homeostasis by exhibiting impaired glucose tolerance & insulin sensitivity, dyslipidemia and steatosis. However, these effects were largely mitigated in HFCR-II offspring. Regarding the obesogenic effects, female offspring exhibited greater susceptibility than male offspring, suggesting that females are more prone to the influences of the paternal diet.

CONCLUSION

The findings highlight that HFCR-I resulted in paternal undernutrition, impacting the health of offspring, whereas HFCR-II largely restored the effects of a high-fat diet on their offspring. As a result, moderate caloric restriction has emerged as an effective weight loss strategy with minimal implications on future generations. This underscores the shared responsibility of fathers in contributing to sperm-specific epigenetic imprints that influence the health of adult offspring.

The effects of paternal dietary fat versus sugar on offspring body composition and anxiety-related behavior

Increasing evidence suggests that the pre-conception parental environment has long-term consequences for offspring health and disease susceptibility. Though much of the work in this field concentrates on maternal influences, there is growing understanding that fathers also play a significant role in affecting offspring phenotypes. In this study, we investigate effects of altering the proportion of dietary fats and carbohydrates on paternal and offspring body composition and anxiety-related behavior in C57Bl/6-JArc mice. We show that in an isocaloric context, greater dietary fat increased body fat and reduced anxiety-like behavior of studs, whereas increased dietary sucrose had no significant effect. These dietary effects were not reflected in offspring traits, rather, we found sex-specific effects that differed between offspring body composition and behavioral traits. This finding is consistent with past paternal effect studies, where transgenerational effects have been shown to be more prominent in one sex over the other. Here, male offspring of fathers fed high-fat diets were heavier at 10 weeks of age due to increased lean body mass, whereas paternal diet had no significant effect on female offspring body fat or lean mass. In contrast, paternal dietary sugar appeared to have the strongest effects on male offspring behavior, with male offspring of high-sucrose fathers spending less time in the closed arms of the elevated plus maze. Both high-fat and high-sugar paternal diets were found to reduce anxiety-like behavior of female offspring, although this effect was only evident when offspring were fed a control diet. This study provides new understanding of the ways in which diet can shape the behavior of fathers and their offspring and contribute to the development of dietary guidelines to improve obesity and mental health conditions, such as anxiety.

Developmentally programmed obesity: Is there a role for anti-inflammatory nutritional strategies?

Pregnancy represents a period of immense maternal physiological adaptation, with progressive increases in lipid storage potential and insulin resistance to support fetal/placental growth. This requires significant change in the adipose tissue. Women living with obesity/overweight are more susceptible to these changes causing complications such as gestational diabetes. This is particularly worrying as up to 60% of European women are living with overweight/obesity at the onset of pregnancy. Furthermore, less than 1% meet all nutrition guidelines. There is now evidence that these deep metabolic changes can result in a predisposition to metabolic disease in both the mother and child in later life. Health and nutrition status during this period therefore represents a window to future health. This period offers a valuable opportunity for intervention to prevent the negative consequences of poor in utero environments and increases the long-term quality of life for mother and offspring. This review will examine a range of in utero factors which determine adipose tissue development, the impact of these factors on later-life obesity and metabolic health and the therapeutic value of dietary anti-inflammatory nutritional interventions during pregnancy and early life. When it comes to early life nutrition, a 'one size fits all' approach is not always appropriate. Understanding the mechanisms of adipose tissue development in response to differing nutritional strategies may be important in the context of complicated or adverse in utero environments and represents a substantial step towards a more personalised nutritional approach for the prevention of obesity, metabolic syndrome and related non-communicable diseases in future generations.

Fish Oil Improves Offspring Metabolic Health of Paternal Obese Mice by Targeting Adipose Tissue

Obesity is a fast-growing epidemic affecting more than 40% of the US population and leads to co-morbidities such as type 2 diabetes and cancer. More importantly, there is a rapid increase in childhood obesity associated with obesity in parents. Further, offspring are encoded with approximately half of their genetic information from the paternal side. Obesity in fathers at the preconceptional period likely influences the intergenerational development of obesity. This study focuses on the role of fish oil supplementation as a non-pharmacological intervention in fathers and its impact on childhood obesity using animal models. Male mice were fed a low-fat diet or high-fat diet with or without fish oil for 10 weeks and mated with female mice on a chow diet. Offspring were then continued on a chow diet until 8 or 16 weeks. In vivo insulin tolerance was tested to assess the metabolic health of offspring. Further, adipose tissue was harvested upon sacrifice, and genetic markers of inflammation and lipid metabolism in the tissue were analyzed. Offspring of males supplemented with fish oil showed lower body weight, improved insulin tolerance, and altered inflammatory markers. Markers of fatty acid oxidation were higher, while markers of fatty acid synthesis were lower in offspring of fathers fed fish oil. This supports fish oil as an accessible intervention to improve offspring metabolic health.

Signatures of metabolic diseases on spermatogenesis and testicular metabolism

Diets leading to caloric overload are linked to metabolic disorders and reproductive function impairment. Metabolic and hormonal abnormalities stand out as defining features of metabolic disorders, and substantially affect the functionality of the testis. Metabolic disorders induce testicular metabolic dysfunction, chronic inflammation and oxidative stress. The disruption of gastrointestinal, pancreatic, adipose tissue and testicular hormonal regulation induced by metabolic disorders can also contribute to a state of compromised fertility. In this Review, we will delve into the effects of high-fat diets and metabolic disorders on testicular metabolism and spermatogenesis, which are crucial elements for male reproductive function. Moreover, metabolic disorders have been shown to influence the epigenome of male gametes and might have a potential role in transmitting phenotype traits across generations. However, the existing evidence strongly underscores the unmet need to understand the mechanisms responsible for transgenerational paternal inheritance of male reproductive function impairment related to metabolic disorders. This knowledge could be useful for developing targeted interventions to prevent, counteract, and most of all break the perpetuation chain of male reproductive dysfunction associated with metabolic disorders across generations.

Role of Fish Oil in Preventing Paternal Obesity and Improving Offspring Skeletal Muscle Health

This study investigates the effects of fish oil supplementation during the periconceptional period in male mice. Specifically, it examines the impact of fish oil on intergenerational health, as determined by skeletal muscle markers. To mimic paternal obesity, thirty mice were separated into three groups with distinct dietary regimes for 10 weeks: a high-fat diet (HF), a high-fat diet supplemented with fish oil (FO), and a low-fat diet (LF). Then, these mice mated with control female mice. Dams and offspring consumed a chow diet during gestation and lactation, and the offspring continued on a chow diet. To study short-term (8 weeks) and long-term (16 weeks) effects of FO, skeletal muscle was isolated at the time of sacrifice, and gene analyses were performed. Results suggest that offspring born to FO-supplemented sires exhibited a significant, short-term upregulation of genes associated with insulin signaling, fatty acid oxidation, and skeletal muscle growth with significant downregulation of genes involved in fatty acid synthesis at 8 weeks. Prominent differences in the above markers were observed at 8 weeks compared to 16 weeks. These findings suggest the potential benefits of FO supplementation for fathers during the periconceptional period in reducing the health risks of offspring due to paternal obesity.

The anti-inflammatory agent 5-ASA reduces the level of specific tsRNAs in sperm cells of high-fat fed C57BL/6J mouse sires and improves glucose tolerance in female offspring

INTRODUCTION

The prevalence of obesity and associated comorbidities have increased to epidemic proportions globally. Paternal obesity is an independent risk factor for developing obesity and type 2 diabetes in the following generation, and growing evidence suggests epigenetic inheritance as a mechanism for this predisposition. How and why obesity induces epigenetic changes in sperm cells remain to be clarified in detail. Yet, recent studies show that alterations in sperm content of transfer RNA-derived small RNAs (tsRNAs) can transmit the effects of paternal obesity to offspring. Obesity is closely associated with low-grade chronic inflammation. Thus, we evaluated whether the anti-inflammatory agent 5-aminosalicylic acid (5-ASA) could intervene in the transmission of epigenetic inheritance of paternal obesity by reducing the inflammatory state in obese fathers.

METHODS

Male C57BL/6JBomTac mice were either fed a high-fat diet or a high-fat diet with 5-ASA for ten weeks before mating. The offspring metabolic phenotype was evaluated, and spermatozoa from sires were isolated for assessment of specific tsRNAs levels.

RESULTS

5-ASA intervention reduced the levels of Glu-CTC tsRNAs in sperm cells and improved glucose tolerance in female offspring fed a chow diet. Paternal high-fat diet-induced obesity per se had only a moderate impact on the metabolic phenotype of both male and female offspring in our setting.

CONCLUSION

The results indicate that the low-grade inflammatory response associated with obesity may be an important factor in epigenetic inheritance of paternal obesity.

Developmental origins of health and disease: Impact of paternal nutrition and lifestyle

Most epidemiological and experimental studies have focused on maternal influences on offspring's health. The impact of maternal undernutrition, overnutrition, hypoxia, and stress is linked to adverse offspring outcomes across a range of systems including cardiometabolic, respiratory, endocrine, and reproduction among others. During the past decade, it has become evident that paternal environmental factors are also linked to the development of diseases in offspring. In this article, we aim to outline the current understanding of the impact of male health and environmental exposure on offspring development, health, and disease and explore the mechanisms underlying the paternal programming of offspring health. The available evidence suggests that poor paternal pre-conceptional nutrition and lifestyle, and advanced age can increase the risk of negative outcomes in offspring, via both direct (genetic/epigenetic) and indirect (maternal uterine environment) effects. Beginning at preconception, and during utero and the early life after birth, cells acquire an epigenetic memory of the early exposure which can be influential across the entire lifespan and program a child's health. Potentially not only mothers but also fathers should be advised that maintaining a healthy diet and lifestyle is important to improve offspring health as well as the parental health status. However, the evidence is mostly based on animal studies, and well-designed human studies are urgently needed to verify findings from animal data.

From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity

This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.

Developmental origins of adult diseases

The occurrence and mechanisms of developmental adult diseases have gradually attracted attention in recent years. Exposure of gametes and embryos to adverse environments, especially during plastic development, can alter the expression of certain tissue-specific genes, leading to increased susceptibility to certain diseases in adulthood, such as diabetes, cardiovascular disease, neuropsychiatric, and reproductive system diseases, etc. The occurrence of chronic disease in adulthood is partly due to genetic factors, and the remaining risk is partly due to environmental-dependent epigenetic information alteration, including DNA methylation, histone modifications, and noncoding RNAs. Changes in this epigenetic information potentially damage our health, which has also been supported by numerous epidemiological and animal studies in recent years. Environmental factors functionally affect embryo development through epimutation, transmitting diseases to offspring and even later generations. This review mainly elaborated on the concept of developmental origins of adult diseases, and revealed the epigenetic mechanisms underlying these events, discussed the theoretical basis for the prevention and treatment of related diseases.

Paternal High-Fat Diet Altered Sperm 5'tsRNA-Gly-GCC Is Associated With Enhanced Gluconeogenesis in the Offspring

Background: Paternal lifestyle, stress and environmental exposures play a crucial role in the health of offspring and are associated with non-genetic inheritance of acquired traits, however the underlying mechanisms are unclear. In this study, we aimed to find out how the sperm tsRNA involved in paternal high-fat diet induced abnormal gluconeogenesis of F1 offspring, and explore the underlying molecular mechanism of its regulation.

Method: We generated a paternal high fat diet (42% kcal fat) model to investigate the mechanism by which paternal diet affects offspring metabolism. Four-week-old C57BL/6J male mice were randomly assigned into two groups to receive either a control diet (CD; 10% kcal fat) or a high-fat (HFD; 42% kcal fat) diet for 10 weeks, and mice from each group were then mated with 8-week-old females with control diet in a 1:2 ratio to generate F1. F0 sperms were isolated and small RNAs was sequenced by high-throughput sequencing. Metabolic phenotypes were examined with both F0 and F1.

Results: A significant increase in body weight was observed with HFD-F0 mice at 8 weeks of age as compared to CD mice at the same age. F0 mice showed impaired glucose tolerance (GTT), resistance to insulin tolerance (ITT) and increased pyruvate tolerance (PTT) at 14 weeks. HFD-F1 male mice showed no significant difference in body weight. An increase in PTT was found at 13 weeks of age and no significant changes in GTT and ITT. PEPCK and G6Pase that related to gluconeogenesis increased significantly in the liver of HFD-F1 male mice. Sperm sequencing results showed that 5′tsRNA-Gly-GCC derived from tRNA-Gly-GCC-2 specifically was remarkably upregulated in sperm of HFD F0 mice. Q-PCR further showed that this tsRNA was also increased in the liver of HFD-F1 comparison with CD-F1 mice. In addition, we found that 5′tsRNA-Gly-GCC can regulate Sirt6-FoxO1 pathway and be involved in the gluconeogenesis pathway in liver.

Conclusion: 5′tsRNA-Gly-GCC that increased in HFD mice mature sperms can promote gluconeogenesis in liver by regulating Sirt6-FoxO1 pathway, which might represent a potential paternal epigenetic factor mediating the intergenerational inheritance of diet-induced metabolic alteration.

Parental Prepuberty Overweight and Offspring Lung Function

In a recent study we found that fathers' but not mothers' onset of overweight in puberty was associated with asthma in adult offspring. The potential impact on offspring's adult lung function, a key marker of general and respiratory health, has not been studied. We investigated the potential causal effects of parents' overweight on adult offspring's lung function within the paternal and maternal lines. We included 929 offspring (aged 18-54, 54% daughters) of 308 fathers and 388 mothers (aged 40-66). Counterfactual-based multi-group mediation analyses by offspring's sex (potential moderator) were used, with offspring's prepubertal overweight and/or adult height as potential mediators. Unknown confounding was addressed by simulation analyses. Fathers' overweight before puberty had a negative indirect effect, mediated through sons' height, on sons' forced expiratory volume in one second (FEV₁) (beta (95% CI): -144 (-272, -23) mL) and forced vital capacity (FVC) (beta (95% CI): -210 (-380, -34) mL), and a negative direct effect on sons' FVC (beta (95% CI): -262 (-501, -9) mL); statistically significant effects on FEV₁/FVC were not observed. Mothers' overweight before puberty had neither direct nor indirect effects on offspring's lung function. Fathers' overweight starting before puberty appears to cause lower FEV₁ and FVC in their future sons. The effects were partly mediated through sons' adult height but not through sons' prepubertal overweight.

Preconception paternal/maternal BMI and risk of small/large for gestational age infant in over 4·7 million Chinese women aged 20-49 years: a population-based cohort study in China

Evidence of couples' BMI and its influence on birth weight is limited and contradictory. Therefore, this study aims to assess the association between couple's preconception BMI and the risk of small for gestational age (SGA)/large for gestational age (LGA) infant, among over 4·7 million couples in a retrospective cohort study based on the National Free Pre-pregnancy Checkups Project between 1 December 2013 and 30 November 2016 in China. Among the live births, 256 718 (5·44 %) SGA events and 506 495 (10·73 %) LGA events were documented, respectively. After adjusting for confounders, underweight men had significantly higher risk (OR 1·17 (95 % CI 1·15, 1·19)) of SGA infants compared with men with normal BMI, while a significant and increased risk of LGA infants was obtained for overweight and obese men (OR 1·08 (95 % CI 1·06, 1·09); OR 1·19 (95 % CI 1·17, 1·20)), respectively. The restricted cubic spline result revealed a non-linear decreasing dose-response relationship of paternal BMI (less than 22·64) with SGA. Meanwhile, a non-linear increasing dose-response relationship of paternal BMI (more than 22·92) with LGA infants was observed. Moreover, similar results about the association between maternal preconception BMI and SGA/LGA infants were obtained. Abnormal preconception BMI in either women or men were associated with increased risk of SGA/LGA infants, respectively. Overall, couple's abnormal weight before pregnancy may be an important preventable risk factor for SGA/LGA infants.

Effects of paternal overnutrition and interventions on future generations

In the last two decades, evidence from human and animal studies suggests that paternal obesity around the time of conception can have adverse effects on offspring health through developmental programming. This may make significant contributions to the current epidemic of obesity and related metabolic and reproductive complications like diabetes, cardiovascular disease, and subfertility/infertility. To date, changes in seminal fluid composition, sperm DNA methylation, histone composition, small non-coding RNAs, and sperm DNA damage have been proposed as potential underpinning mechanism to program offspring health. In this review, we discuss current human and rodent evidence on the impact of paternal obesity/overnutrition on offspring health, followed by the proposed mechanisms, with a focus on sperm DNA damage underpinning paternal programming. We also summarize the different intervention strategies implemented to minimize effects of paternal obesity. Upon critical review of literature, we find that obesity-induced altered sperm quality in father is linked with compromised offspring health. Paternal exercise intervention before conception has been shown to improve metabolic health. Further work to explore the mechanisms underlying benefits of paternal exercise on offspring are warranted. Conversion to healthy diets and micronutrient supplementation during pre-conception have shown some positive impacts towards minimizing the impact of paternal obesity on offspring. Pharmacological approaches e.g., metformin are also being applied. Thus, interventions in the obese father may ameliorate the potential detrimental impacts of paternal obesity on offspring.

Ameliorating high-fat diet-induced sperm and testicular oxidative damage by micronutrient-based antioxidant intervention in rats

PURPOSE

Emerging evidence from rodent studies suggests that high-fat-diet (HFD)-induced obesity is characterized by increased oxidative damage in sperm and testis. However, interventions using micronutrient supplementation to mitigate oxidative damage in obesity have not been extensively studied. This study aimed to investigate the effect of an antioxidant-based micronutrient supplement (added folate, vitamin B₆, choline, betaine, and zinc) on sperm and testicular oxidative damage in HFD-fed male Sprague Dawley rats.

METHODS

Rats (3-weeks-old, 12/group) were weaned onto control (C) or HFD (H) or these diets with micronutrient supplement (CS; HS); sperm and testis were harvested at 30.5 weeks. To assess oxidative stress and antioxidant capacity in testis, levels of malondialdehyde (MDA), glutathione (GSH), folate and susceptibility index (SI) of pro-oxidative damage, mRNA expression of Nrf2, NFκB-p65, IL-6, IL-10 and TNF-α, in addition to superoxide-dismutase (SOD), catalase and glutathione-peroxidase (GPx) activities were measured. 8-hydroxy-2-deoxyguanosine (8-OHdG) were assessed in both sperm and testis.

RESULTS

HFD-fed rats had significantly increased 8-OHdG content in sperm and testis, increased testicular SI, decreased testicular weight, SOD and GPx activity compared to control. Strikingly, supplementation of HFD appeared to significantly reduce 8-OHdG in sperm and testis (22% and 24.3%, respectively), reduce testicular SI and MDA content (28% and 40%, respectively), increase testicular weight (24%), SOD and GPX activity (30% and 70%, respectively) and GSH content (19%). Moreover, supplementation had significant impact to increase testicular folate content regardless of diet. Furthermore, an overall effect of supplementation to increase testicular mRNA expression of Nrf2 was observed across groups. Interestingly, testicular SI was positively correlated with sperm and testicular 8-OHdG and MDA content, suggesting a critical role of testicular antioxidant activity to combat oxidative damage in sperm and testis.

CONCLUSION

Our findings suggest that antioxidant-based micronutrient supplement has the potential to interrupt HFD-induced sperm and testicular oxidative damage by improving testicular antioxidant capacity.

Metabolic syndrome and male fertility disorders: Is there a causal link?

Infertility is a global health problem affecting 10-15% of couples in reproductive age. Recent studies have provided growing evidence supporting that lifestyle factors can affect male fertility through alterations in endocrine profiles, spermatogenesis and/or sperm function. One of these critical factors could be the change in the food intake behavior in modern societies that produces metabolic alterations. Regarding this, metabolic syndrome (MetS) prevalence has increased in epidemic in the last 40-50 years. Although MetS is associated with advanced age, changes in lifestyles have accelerated the appearance of symptoms in the reproductive age. We review herein the current understanding of the relationship between MetS and the male reproductive status. For this purpose, in this narrative review a comprehensive literature search was made in both animal models and men, allowing us to evaluate such relationship. This analysis showed a high variability in the reproductive phenotypes observed in patients and mice suffering MetS, including sperm parameters, fertility and offspring health. In view of this, we proposed that the reproductive effects, which are diverse and not robust, observed among MetS-affected males, might depend on additional factors not associated with the metabolic condition and contributed not only by the affected male but also by his partner. With this perspective, this review provides a more accurate insight of this syndrome critical for the identification of specific diagnostic indicators and treatment of MetS-induced fertility disorders.

Association of parental prepregnancy BMI with neonatal outcomes and birth defect in fresh embryo transfer cycles: a retrospective cohort study

Background

Parental body mass index (BMI) is associated with pregnancy outcomes. But the effect of parental prepregnancy BMI on offspring conceived via in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), especially the birth defect, remains to be determined. This study aimed to investigate the associations of parental prepregnancy BMI with neonatal outcomes and birth defect in fresh embryo transfer cycles.

Methods

We conducted a retrospective cohort study including 5741 couples in their first fresh IVF/ICSI cycles admitted to Women’s Hospital, School of Medicine, Zhejiang University from January 2013 to July 2016. The primary outcome was birth defects, which was classified according to the International Classification of Diseases, 10th Revision. Secondary outcomes included preterm delivery rate, infant gender, birth weight, small-for-gestational age (SGA) and large-for-gestational age (LGA). Multilevel regression analyses were used to assess the associations of parental prepregnancy BMI with neonatal outcomes and birth defect.

Results

In singletons, couples with prepregnancy BMI ≥25 kg/m² had higher odds of LGA than those with BMI < 25 kg/m². The birth defect rate was significantly higher when paternal prepregnancy BMI ≥25 kg/m² in IVF cycles (aOR 1.82, 95% CI 1.06–3.10) and maternal BMI ≥25 kg/m² in ICSI cycles (aOR 4.89, 95% CI 1.45–16.53). For subcategories of birth defects, only the odds of congenital malformations of musculoskeletal system was significantly increased in IVF offspring with paternal BMI ≥25 kg/m² (aOR 4.55, 95% CI 1.32–15.71). For twins, there was no significant difference among four groups, except for the lower birth weight of IVF female infants.

Conclusions

Parental prepregnancy BMI ≥25 kg/m² is associated with higher incidence of LGA in IVF/ICSI singletons. Paternal prepregnancy BMI ≥25 kg/m² was likely to have higher risk of birth defect in IVF offspring than those with BMI < 25 kg/m², particularly in the musculoskeletal system. It is essential for overweight or obesity couples to lose weight before IVF/ICSI treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04261-y.

Paternal long-term PM2.5 exposure causes hypertension via increased renal AT1R expression and function in male offspring

Maternal exposure to fine particulate matter (PM2.5) causes hypertension in offspring. However, paternal contribution of PM2.5 exposure to hypertension in offspring remains unknown. In the present study, male Sprague-Dawley rats were treated with PM2.5 suspension (10 mg/ml) for 12 weeks and/or fed with tap water containing an antioxidant tempol (1 mM/L) for 16 weeks. The blood pressure, 24 h-urine volume and sodium excretion were determined in male offspring. The offspring were also administrated with losartan (20 mg/kg/d) for 4 weeks. The expressions of angiotensin II type 1 receptor (AT1R) and G-protein-coupled receptor kinase type 4 (GRK4) were determined by qRT-PCR and immunoblotting. We found that long-term PM2.5 exposure to paternal rats caused hypertension and impaired urine volume and sodium excretion in male offspring. Both the mRNA and protein expression of GRK4 and its downstream target AT1R were increased in offspring of PM2.5-exposed paternal rats, which was reflected in its function because treatment with losartan, an AT1R antagonist, decreased the blood pressure and increased urine volume and sodium excretion. In addition, the oxidative stress level was increased in PM2.5-treated paternal rats. Administration with tempol in paternal rats restored the increased blood pressure and decreased urine volume and sodium excretion in the offspring of PM2.5-exposed paternal rats. Treatment with tempol in paternal rats also reversed the increased expressions of AT1R and GRK4 in the kidney of their offspring. We suggest that paternal PM2.5 exposure causes hypertension in offspring. The mechanism may be involved that paternal PM2.5 exposure-associated oxidative stress induces the elevated renal GRK4 level, leading to the enhanced AT1R expression and its-mediated sodium retention, consequently causes hypertension in male offspring.

Effects of Micronutrient Supplementation on Glucose and Hepatic Lipid Metabolism in a Rat Model of Diet Induced Obesity

Obesity increases the risk of metabolic disorders, partly through increased oxidative stress. Here, we examined the effects of a dietary micronutrient supplement (consisting of folate, vitamin B6, choline, betaine, and zinc) with antioxidant and methyl donor activities. Male Sprague Dawley rats (3 weeks old, 17/group) were weaned onto control (C) or high-fat diet (HFD) or same diets with added micronutrient supplement (CS; HS). At 14.5 weeks of age, body composition was measured by magnetic resonance imaging. At 21 weeks of age, respiratory quotient and energy expenditure was measured using Comprehensive Lab Animal Monitoring System. At 22 weeks of age, an oral glucose tolerance test (OGTT) was performed, and using fasting glucose and insulin values, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated as a surrogate measure of insulin resistance. At 30.5 weeks of age, blood and liver tissues were harvested. Liver antioxidant capacity, lipids and expression of genes involved in lipid metabolism (Cd36, Fabp1, Acaca, Fasn, Cpt1a, Srebf1) were measured. HFD increased adiposity (p < 0.001) and body weight (p < 0.001), both of which did not occur in the HS group. The animals fed HFD developed impaired fasting glucose, impaired glucose tolerance, and fasting hyperinsulinemia compared to control fed animals. Interestingly, HS animals demonstrated an improvement in fasting glucose and fasting insulin. Based on insulin release during OGTT and HOMA-IR, the supplement appeared to reduce the insulin resistance developed by HFD feeding. Supplementation increased hepatic glutathione content (p < 0.05) and reduced hepatic triglyceride accumulation (p < 0.001) regardless of diet; this was accompanied by altered gene expression (particularly of CPT-1). Our findings show that dietary micronutrient supplementation can reduce weight gain and adiposity, improve glucose metabolism, and improve hepatic antioxidant capacity and lipid metabolism in response to HFD intake.

Paternal obesity impairs hepatic gluconeogenesis of offspring by altering Igf2/H19 DNA methylation

Over the past four decades, the global prevalence of obesity has increased rapidly in all age ranges. Emerging evidence suggests that paternal lifestyle and environmental exposure have a crucial role in the health of offspring. Therefore, the current study investigated the impact of paternal obesity on the metabolic profile of offspring in a male mouse model of obesity. Female offspring of obese fathers fed a high-fat diet (HFD) (60% kcal fat) showed hyperglycemia because of enhanced gluconeogenesis and elevated expression of phosphoenolpyruvate carboxykinase (PEPCK), which is a key enzyme involved in the regulation of gluconeogenesis. Methylation of the Igf2/H19 imprinting control region (ICR) was dysregulated in the liver of offspring, and the sperm, of HFD fathers, suggesting that epigenetic changes in germ cells contribute to this father-offspring transmission. In addition, we explored whether H19 might regulate hepatic gluconeogenesis. Our results showed that overexpression of H19 in Hepa1-6 cells enhanced the expression of PEPCK and gluconeogenesis by promoting nuclear retention of forkhead box O1 (FOXO1), which is involved in the transcriptional regulation of Pepck. Thus, the current study suggests that paternal exposure to HFD impairs the gluconeogenesis of offspring via altered Igf2/H19 DNA methylation.

Paternal obesity and its transgenerational effects on gastrointestinal function in male rat offspring

The interplay between obesity and gastrointestinal (GI) motility is contradictory, and the transgenerational influence on this parameter is unknown. We aimed to evaluate the GI function in a model of paternal obesity and two subsequent generations of their male offspring. Newborn male rats were treated with monosodium glutamate (MSG) and composed the F1 generation, while control rats (CONT) received saline. At 90 days, male F1 were mated with non-obese females to obtain male offspring (F2), which later mated with non-obese females for obtaining male offspring of F3 generation. Lee Index analysis was adopted to set up the obesity groups. Alternating current biosusceptometry (ACB) technique was employed to calculate GI transit parameters: mean gastric emptying time (MGET), mean cecum arrival time (MCAT), mean small intestinal transit time (MSITT), and gastric frequency and amplitude of contractions. Glucose, insulin, and leptin levels and duodenal morphometry were measured. F1 obese rats showed a decrease in the frequency and amplitude of gastric contractions, while obese rats from the F2 generation showed accelerated MGET and delayed MCAT and MSITT. Glucose and leptin levels were increased in F1 and F2 generations. Insulin levels decreased in F1, F2, and F3 generations. Duodenal morphometry was altered in all three generations. Obesity may have paternal transgenerational transmission, and it provoked disturbances in the gastrointestinal function of three generations.

Paternal trans-fatty acid and vitamin E diet affects rat offspring's semen quality and PPARs expression

Trans-fatty acids (TFAs) consumption has created concerns regarding male/female reproductive system. However, the effects of TFA in paternal diet on offspring's reproduction have not been addressed. The purpose of this study is to investigate the effects of rat paternal TFAs and vitamin E consumption on offspring's sperm quality and expression pattern of peroxisome proliferator-activated receptors (PPARs) in testis tissues. Forty adult male rats were randomly divided into four groups: Control diet (C); Control diet plus TFA (CTH); diet supplemented with vitamin E (E) and a diet containing vitamin E and TFA (ETH). Mother rats had normal diet during gestation period. Three offspring from each group were chosen randomly and their testicular samples were collected, and sperm parameters were measured by CASA. Our results indicate that feeding fathers with TFA can negatively affect offspring's sperm concentration and motility, while consumption of vitamin E can improve these parameters (p < .05). The paternal diet containing TFA down-regulated the expression of PPARβ and PPARγ genes, whereas vitamin E-containing diet up-regulated the transcription of PPAR genes. In conclusion, TFA intake in paternal diet may have negative effects on reproductive system of the offspring while vitamin E may not diminish these effects.

Nutritional and developmental programming effects of insulin

The discovery of insulin in 1921 was a major breakthrough in medicine and for therapy in patients with diabetes. The dramatic rise in the prevalence of overweight and obesity has been tightly linked to an increased prevalence of gestational diabetes mellitus (GDM), which poses major health concerns. Babies born to GDM mothers are more likely to develop obesity, type 2 diabetes and cardiovascular disease later in life. Evidence accumulated during the past two decades has revealed that high levels insulin, such as those observed during GDM, can have a widespread effect on the development and function of a variety of organs. This review summarises our current knowledge on the role of insulin in the placenta, cardiovascular system and brain during critical periods of development, as well as how it can contribute to lifelong metabolic regulation. We also discuss possible intervention strategies to ameliorate and hopefully reverse the developmental defects associated with obesity and GDM.

Paternal metabolic and cardiovascular programming of their offspring: A systematic scoping review

BACKGROUND

There is lots of evidence that maternal peri-gestational metabolic, genomic and environmental conditions are closely linked to metabolic and cardiovascular outcomes in their offspring later in life. Moreover, there is also lotsof evidence that underlining mechanisms, such as molecular as well as epigenetic changes may alter the intrauterine environment leading to cardio-metabolic diseases in their offspring postnatal. But, there is also increasing evidence that cardio-metabolic diseases may be closely linked to their paternal metabolic risk factors, such as obesity, Type 2 Diabetes and other risk factors.

OBJECTIVE

To analyse the evidence as well as specific risk factors of paternal trans-generational programming of cardio-metabolic diseases in their offspring.

METHODS

Within a systematic scoping review, we performed a literature search in MEDLINE (PubMed) and EMBASE databases in August 2020 considering original research articles (2000-2020) that examined the impact of paternal programming on metabolic and cardiovascular offspring health. Epidemiological, clinical and experimental studies as well as human and animal model studies were included.

RESULTS

From n = 3.199 citations, n = 66 eligible studies were included. We selected n = 45 epidemiological as well as clinical studies and n = 21 experimental studies. In brief, pre-conceptional paternal risk factors, such as obesity, own birth weight, high-fat and low-protein diet, undernutrition, diabetes mellitus, hyperglycaemia, advanced age, smoking as well as environmental chemical exposure affect clearly metabolic and cardiovascular health of their offspring later in life.

CONCLUSIONS

There is emerging evidence that paternal risk factors, such as paternal obesity, diabetes mellitus, nutritional habits, advanced age and exposure to environmental chemicals or cigarette smoke, are clearly associated with adverse effects in metabolic and cardiovascular health in their offspring. Compared to maternal programming, pre-conceptional paternal factors might also have also a substantial effect in the sense of trans-generational programming of their offspring and need further research.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Mapping the past, present and future research landscape of paternal effects

BACKGROUND

Although in all sexually reproducing organisms an individual has a mother and a father, non-genetic inheritance has been predominantly studied in mothers. Paternal effects have been far less frequently studied, until recently. In the last 5 years, research on environmentally induced paternal effects has grown rapidly in the number of publications and diversity of topics. Here, we provide an overview of this field using synthesis of evidence (systematic map) and influence (bibliometric analyses).

RESULTS

We find that motivations for studies into paternal effects are diverse. For example, from the ecological and evolutionary perspective, paternal effects are of interest as facilitators of response to environmental change and mediators of extended heredity. Medical researchers track how paternal pre-fertilization exposures to factors, such as diet or trauma, influence offspring health. Toxicologists look at the effects of toxins. We compare how these three research guilds design experiments in relation to objects of their studies: fathers, mothers and offspring. We highlight examples of research gaps, which, in turn, lead to future avenues of research.

CONCLUSIONS

The literature on paternal effects is large and disparate. Our study helps in fostering connections between areas of knowledge that develop in parallel, but which could benefit from the lateral transfer of concepts and methods.

Paternal exercise protects against liver steatosis in the male offspring of mice submitted to high fat diet

Parental lifestyle has been related to alterations in the phenotype of their offspring. Obese sires can induce offspring insulin resistance as well as increase susceptibility to obesity. On the other hand, obese sires submitted to voluntary exercise ameliorate the deleterious metabolic effects on their offspring. However, there are no studies reporting the effect of programmed exercise training of lean sires on offspring metabolism.

AIMS

This study aimed to investigate the role of swimming training of sires for 6 weeks on the offspring metabolic phenotype.

MAIN METHODS

Male C57BL/6 mice fed a control diet were divided into sedentary and swimming groups. After the exercise, they were mated with sedentary females, and body weight and molecular parameters of the offspring were subsequently monitored.

KEY FINDINGS

Swimming decreased the gene expression of Fasn and Acaca in the testes and increased the AMPK protein content in the testes and epididymis of the sires. The progeny presented a low weight at P1, which reached a normal level at P60 and at P90 the animals were challenged with HFD for 16 weeks. The male offspring of trained sires presented less body weight gain than the control group. The level of steatosis decreased in the male offspring from trained sires. The gene expression of Prkaa2, Ppar-1α and Cpt-1 was also increased in the liver of male offspring from trained sires.

SIGNIFICANCE

Taken together, these findings suggest that paternal exercise training can improve the metabolic profile in the liver of the progeny, thereby ameliorating the effects of obesity.

Maternal but Not Paternal High-Fat Diet (HFD) Exposure at Conception Predisposes for 'Diabesity' in Offspring Generations

While environmental epigenetics mainly focuses on xenobiotic endocrine disruptors, dietary composition might be one of the most important environmental exposures for epigenetic modifications, perhaps even for offspring generations. We performed a large-scale rat study on key phenotypic consequences from parental (F0) high-caloric, high-fat diet (HFD) food intake, precisely and specifically at mating/conception, focusing on ‘diabesity’ risk in first- (F1) and second- (F2) generation offspring of both sexes. F0 rats (maternal or paternal, respectively) received HFD overfeeding, starting six weeks prior to mating with normally fed control rats. The maternal side F1 offspring of both sexes developed a ‘diabesity’ predisposition throughout life (obesity, hyperleptinemia, hyperglycemia, insulin resistance), while no respective alterations occurred in the paternal side F1 offspring, neither in males nor in females. Mating the maternal side F1 females with control males under standard feeding conditions led, again, to a ‘diabesity’ predisposition in the F2 generation, which, however, was less pronounced than in the F1 generation. Our observations speak in favor of the critical impact of maternal but not paternal metabolism around the time frame of reproduction for offspring metabolic health over generations. Such fundamental phenotypic observations should be carefully considered in front of detailed molecular epigenetic approaches on eventual mechanisms.

Paternal weight of ducks may have an influence on offspring' small intestinal function and cecal microorganisms

Background

In animals, many factors affect the small intestinal function and cecal microorganisms, including body weight and genetic background. However, whether paternal weight impacts the small intestinal function and cecal microorganisms remains unknown to date. The current study used Nonghua sheldrake to estimate the effect of paternal weight on the intestine of the offspring by evaluating differences in small intestinal morphology, digestive enzyme activity, and cecal microorganisms between the offspring of male parents with high body weight (group H) and that of male parents with low body weight (group L).

Results

The results of the analysis of small intestinal morphology showed that the villus height of the jejunum of group H ducks was higher than that of group L ducks, and the difference was significant for ducks at 10 weeks of age. Moreover, the villus height/crypt depth of the duodenum in group H significantly exceeded that of group L at a duck age of 2 weeks. The amylase activity in the jejunum content of group H exceeded that of group L at 5 and 10 weeks of age. Furthermore, the proportion of the Firmicutes to Bacteroidetes was significantly higher in group H (duck age of 2 weeks). Among the genera with a relative abundance exceeding 1%, the relative abundances of genera Desulfovibrio, Megamonas, Alistipes, Faecalibacterium, and Streptococcus observed in group H were significantly different between group H and group L.

Conclusions

For the first time, this study identifies the effect of paternal weight on offspring small intestinal function and cecal microorganisms. Consequently, this lays a foundation for further research on the relationship between male parents and offspring intestinal function.

Effect of paternal body mass index on neonatal outcomes of singletons after frozen-thawed embryo transfer cycles: analysis of 7,908 singleton newborns

OBJECTIVE

To investigate the effect of paternal body mass index (BMI) on neonatal outcomes of singletons after frozen-thawed embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical center.

PATIENT(S)

A total of 7,908 singleton newborns were divided into four categories based on their paternal BMI: 284 (3.6%) infants were in the paternal underweight category, 4,678 (59.2%) infants were in the paternal normal weight category, 2,585 (32.7%) infants were in the paternal overweight category, and 361 (4.6%) infants were in the paternal obesity category. In addition, we included only infants of women with normal BMI (18.5 kg/m² ≤ BMI < 25 kg/m²).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Neonatal outcomes.

RESULT(S)

The rates of large for gestational age (LGA) infants were significantly higher among those in the paternal overweight and obesity categories than those in the paternal underweight categories. The rates of very LGA were higher among infants in the paternal overweight categories and lower among infants in the paternal underweight categories than the rates in normal controls. The rates of fetal macrosomia were higher among infants in the paternal overweight categories than among infants in the paternal normal weight categories. Compared with normal controls, Z-scores (gestational age- and sex-adjusted birthweight) were significantly higher among the infants in the paternal overweight and paternal obesity categories and significantly lower among the infants in the paternal underweight categories. A positive association was observed in a multiple linear regression model between paternal BMI and newborn birthweights after adjustment for several potential confounders.

CONCLUSION(S)

Paternal BMI had an independent impact on the birthweight of singletons born after FET cycles. Paternal overweight and paternal obesity were independent risk factors for having LGA infants after FET cycles. Furthermore, paternal overweight was an independent risk factor for fathering infants with macrosomia or very LGA infants after FET cycles.

Parental adiposity differentially associates with newborn body composition

BACKGROUND

Maternal obesity increases offspring's obesity risk. However, studies have not often considered maternal metabolic and exercise patterns as well as paternal adiposity as potential covariates.

OBJECTIVE

To assess the relationship between parental and newborn adiposity.

METHODS

Participants were mother-child pairs (n = 209) and mother-father-offspring triads (n = 136). Parental (during gestation) and offspring (2 weeks old) percent fat mass (FM) were obtained using air displacement plethysmography. Maternal race, age, resting energy expenditure (indirect calorimetry), physical activity (accelerometry), gestational weight gain (GWG), gestational age (GA), delivery mode, infant's sex and infant feeding method were incorporated in multiple linear regression analyses. The association between parental FM and offspring insulin-like growth factor 1 (IGF-1) was assessed at age 2 years.

RESULTS

Maternal adiposity was positively-associated with male (β = 0.11, P = .015) and female (β = 0.13, P = .008) infant FM, whereas paternal adiposity was negatively-associated with male newborn adiposity (β = -0.09, P = .014). Breastfeeding, female sex, GA and GWG positively associated with newborn adiposity. Vaginal and C-section delivery methods associated with greater adiposity than vaginal induced delivery method. Plasma IGF-1 of 2-year-old boys and girls positively associated with their respective fathers' and mothers' FM.

CONCLUSIONS

Maternal and paternal adiposity differentially associate with newborn adiposity. The mechanisms of this finding remain to be determined.

Paternal high-fat diet and exercise regulate sperm miRNA and histone methylation to modify placental inflammation, nutrient transporter mRNA expression and fetal weight in a sex-dependent manner

We previously have shown that male offspring (F1) of fathers (F0) fed a high-fat (HF) diet and that exercised had greater skeletal muscle insulin signaling and reduced type 2 diabetes mellitus (T2DM) risk compared to fathers fed HF diet and that remained sedentary. The current study extends this work by hypothesizing that F0 HF diet and exercise regulate F1 T2DM risk by alterations in placental tissue growth via changes in sperm miRNA expression. To test these hypotheses, 3-week-old male C57BL/6 mice were fed a normal-fat diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months. Results showed that F0 sperm miRNA 193b expression was decreased while miRNA 204 was increased by paternal exercise. Protein expression of dimethylated histone 3 lysine 9 was decreased with F0 HF diet. Placental and fetal tissue weights were decreased by F0 HF diet in F1 males. Placental interleukin-1β and tumor necrosis factor (TNF)-α mRNA expression was reduced by paternal exercise, while nutrient transporter mRNA expression was decreased by paternal HF diet only in the placentae of F1 females. Treatment of primary placental cell with miRNA 193b inhibited TNF-α mRNA expression, and treatment of TNF-α decreased SLC38a2 mRNA expression. Moreover, paternal exercise increased body weight at weaning in a female offspring. These results demonstrate that placental tissue weight, placental nutrient transporter gene expression and fetal weights are altered by paternal exercise, while placental inflammatory gene expression is influenced by paternal exercise in offspring in a sex-specific manner.

Environmental and Nutritional Effects Regulating Adipose Tissue Function and Metabolism Across Generations

The unabated rise in obesity prevalence during the last 40 years has spurred substantial interest in understanding the reasons for this epidemic. Studies in mice and humans have demonstrated that obesity is a highly heritable disease; however genetic variations within specific populations have so far not been able to explain this phenomenon to its full extent. Recent work has demonstrated that environmental cues can be sensed by an organism to elicit lasting changes, which in turn can affect systemic energy metabolism by different epigenetic mechanisms such as changes in small noncoding RNA expression, DNA methylation patterns, as well as histone modifications. These changes can directly modulate cellular function in response to environmental cues, however research during the last decade has demonstrated that some of these modifications might be transmitted to subsequent generations, thus modulating energy metabolism of the progeny in an inter- as well as transgenerational manner. In this context, adipose tissue has become a focus of research due to its plasticity, which allows the formation of energy storing (white) as well as energy wasting (brown/brite/beige) cells within the same depot. In this Review, the effects of environmental induced obesity with a particular focus on adipose tissue are discussed.

Taurine supplementation in high-fat diet fed male mice attenuates endocrine pancreatic dysfunction in their male offspring

Obesity in fathers leads to DNA damage and epigenetic changes in sperm that may carry potential risk factors for metabolic diseases to the next generation. Taurine (TAU) supplementation has demonstrated benefits against testicular dysfunction and pancreatic islet impairments induced by obesity, but it is not known if these protective actions prevent the propagation of metabolic disruptions to the next generation; as such, we hypothesized that paternal obesity may increase the probability of endocrine pancreatic dysfunction in offspring, and that this could be prevented by TAU supplementation in male progenitors. To test this, male C57Bl/6 mice were fed on a control diet (CTL) or a high-fat diet (HFD) without or with 5% TAU in their drinking water (CTAU and HTAU) for 4 months. Subsequently, all groups of mice were mated with CTL females, and the F1 offspring were identified as: CTL-F1, CTAU-F1, HFD-F1, and HTAU-F1. HFD-fed mice were normoglycemic, but glucose intolerant and their islets hypersecreted insulin. However, at 90 days of age, HFD-F1 offspring displayed normal glucose homeostasis and adiposity, but reduced glucose-induced insulin release. HFD-F1 islets also exhibited β- and α-cell hypotrophy, and lower δ-cell number per islet. Paternal TAU supplementation prevented the decrease in glucose-induced insulin secretion and normalized β-cell size and δ-cell number, and increased α-cell size/islet in HTAU-F1 mice. In conclusion, HFD consumption by male founders decreases β-cell secretion and islet-cell distribution in their offspring. TAU attenuates the deleterious effects of paternal obesity on insulin secretion and islet-cell morphology in F1 offspring.

Four weeks of exercise early in life reprograms adult skeletal muscle insulin resistance caused by a paternal high-fat diet

KEY POINTS

A paternal high-fat diet/obesity before mating can negatively influence the metabolism of offspring. Exercise only early in life has a remarkable effect with respect to reprogramming adult rat offspring exposed to detrimental insults before conception. Exercise only early in life normalized adult whole body and muscle insulin resistance as a result of having a high-fat fed/obese father. Unlike the effects on the muscle, early exercise did not normalize the reduced adult pancreatic beta cell mass as a result of having a high-fat fed/obese father. Early-life exercise training may be able to reprogram an individual whose father was obese, inducing long-lasting beneficial effects on health.

ABSTRACT

A paternal high-fat diet (HFD) impairs female rat offspring glucose tolerance, pancreatic morphology and insulin secretion. We examined whether only 4 weeks of exercise early in life could reprogram these negative effects. Male Sprague-Dawley rats consumed a HFD for 10 weeks before mating with chow-fed dams. Female offspring remained sedentary or performed moderate intensity treadmill exercise (5 days week^-1 , 60 min day^-1 , 20 m min^-1 ) from 5 to 9 weeks of age. Paternal HFD impaired (P < 0.05) adult offspring whole body insulin sensitivity (i.p. insulin sensitivity test), as well as skeletal muscle ex vivo insulin sensitivity and TBC1D4 phosphorylation. It also lowered β-cell mass and reduced in vivo insulin secretion in response to an i.p. glucose tolerance test. Early-life exercise in offspring reprogrammed the negative effects of a paternal HFD on whole body insulin sensitivity, skeletal muscle ex vivo insulin-stimulated glucose uptake and TBC1D4 phosphorylation and also increased glucose transporter 4 protein. However, early exercise did not normalize the reduced pancreatic β-cell mass or insulin secretion. In conclusion, only 4 weeks of exercise early in life in female rat offspring reprograms reductions in insulin sensitivity in adulthood caused by a paternal HFD without affecting pancreatic β-cell mass or insulin secretion.

Pleiotropic Impacts of Macrophage and Microglial Deficiency on Development in Rats with Targeted Mutation of the Csf1r Locus

We have produced Csf1r-deficient rats by homologous recombination in embryonic stem cells. Consistent with the role of Csf1r in macrophage differentiation, there was a loss of peripheral blood monocytes, microglia in the brain, epidermal Langerhans cells, splenic marginal zone macrophages, bone-associated macrophages and osteoclasts, and peritoneal macrophages. Macrophages of splenic red pulp, liver, lung, and gut were less affected. The pleiotropic impacts of the loss of macrophages on development of multiple organ systems in rats were distinct from those reported in mice. Csf1r^-/- rats survived well into adulthood with postnatal growth retardation, distinct skeletal and bone marrow abnormalities, infertility, and loss of visceral adipose tissue. Gene expression analysis in spleen revealed selective loss of transcripts associated with the marginal zone and, in brain regions, the loss of known and candidate novel microglia-associated transcripts. Despite the complete absence of microglia, there was little overt phenotype in brain, aside from reduced myelination and increased expression of dopamine receptor-associated transcripts in striatum. The results highlight the redundant and nonredundant functions of CSF1R signaling and of macrophages in development, organogenesis, and homeostasis.

Paternal exercise protects mouse offspring from high-fat-diet-induced type 2 diabetes risk by increasing skeletal muscle insulin signaling

Paternal obesity increases, while paternal exercise decreases, offspring obesity and type 2 diabetes (T2D) risk; however, no studies have determined whether a paternal high-fat (HF) diet and exercise interact to alter offspring body weight (BW), adiposity and T2D risk. Three-week-old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF-diet-fed dams. After weaning, male offspring were fed an NF or HF diet for an additional 3 months. F1 male mice whose fathers ate an HF diet had decreased % body fat accompanied by decreased gene expression of beige adipocyte marker FGF21. However, paternal HF-diet-induced reductions in F1 offspring % body fat normalized but did not reduce T2D risk. Exercise was protective against paternal HF-diet-induced insulin resistance by increasing the expression of insulin signaling (GLUT4, IRS1 and PI3K) markers in skeletal muscle resulting in normal T2D risk. When fathers were fed an HF diet and exercised, a postnatal HF diet increased beiging (PPARγ). Thus, these findings show that increases in T2D risk in male offspring when the father consumes an HF diet can be normalized when the father also exercises preconception and that this protection may occur by increases in insulin signaling potential within offspring skeletal muscle. Future studies should further determine the physiological mechanism(s) underlying the beneficial effects of exercise through the paternal lineage.

Paternal high-fat diet enhances offspring whole-body insulin sensitivity and skeletal muscle insulin signaling early in life

Evidence suggests that paternal diet can predispose offspring to metabolic dysfunction. Despite this knowledge, little is known regarding the effects of paternal high-fat feeding on offspring insulin sensitivity. The purpose of this study was to investigate for the first time the effects of paternal high-fat feeding on whole-body and skeletal muscle insulin action in young and adult offspring. At 4 weeks of age, founder C57BL6/N males (F0) were fed a high-fat diet or control diet for 12 weeks and then bred with females on a control diet. Offspring (F1) were euthanized at 6 weeks, 6 months, or 12 months and insulin-stimulated insulin signaling was measured ex vivo in isolated soleus muscle. At 6 weeks of age, paternal high fat offspring (HFO) had enhanced whole-body insulin sensitivity (35%, P < 0.05), as well as, increased insulin-stimulated skeletal muscle phosphorylation of Akt threonine 308 (70%, P < 0.05) and AS160 threonine 642 (80%, P < 0.05) compared to paternal control fed offspring (CFO), despite both offspring groups consuming standard chow. At 6 months of age, HFO had increased percent body fat compared to CFO (74%, P < 0.005) and whole-body and skeletal muscle insulin signaling normalized to CFO. Body fat was inversely related with insulin signaling in HFO, but not CFO. These findings suggest that paternal high-fat feeding contributes to enhanced whole-body and skeletal muscle insulin sensitivity in HFO early in life; however, these benefits are lost by early adulthood, potentially due to premature increases in body fat.

Therapies for gestational diabetes and their implications for maternal and offspring health: Evidence from human and animal studies

Obesity prior to and during pregnancy is associated with an increased risk of complications during pregnancy. One of the most common complications of pregnancy is gestational diabetes mellitus (GDM), a condition characterized by hyperglycemia and insulin resistance that is diagnosed in the third trimester of pregnancy. GDM predisposes both mothers and their children to increased obesity and cardiometabolic disorders, namely type 2 diabetes and cardiovascular disease. Current treatments include lifestyle changes and insulin injections, but oral anti-diabetic drugs such as metformin and glyburide are increasingly prescribed as they do not require injections. However, the long-term implications of therapies for diabetes during pregnancy on mothers and their offspring are not fully understood. In this review, we describe current treatments for GDM, including the first line lifestyle interventions such as exercise as well as insulin, glyburides and metformin. We also review selected natural health products that are sometimes used by individuals during pregnancy that could also be an effective therapeutic in pregnancies characterized by obesity or GDM. We focus on both the short- and long-term effects of treatments on the health of mothers and their offspring. We review the current literature from clinical research and animal studies.

Obesity, a serious etiologic factor for male subfertility in modern society

Obesity, defined as excessive accumulation of fat in adipose tissue, is a metabolic disorder resulting from behavioral, environmental and heritable causes. Obesity increases the risks of hypertension, diabetes, cardiovascular disease, sleep apnea, respiratory problems, osteoarthritis and cancer. Meanwhile, the negative impact of obesity on male reproduction is gradually recognized. According to the clinical investigations and animal experiments, obesity is correlated with reductions in sperm concentration and motility, increase in sperm DNA damage and changes in reproductive hormones. Several mechanisms can elucidate the effects of obesity on sperm functions and male subfertility, i.e., the excessive conversion of androgens into estrogens in redundant adipose tissue causes sexual hormone imbalance, subsequently resulting in hypogonadism. Secondly, adipokines produced by adipose tissue induce severe inflammation and oxidative stress in male reproductive tract, directly impairing testicular and epididymal tissues. Moreover, increased scrotal adiposity leads to increase gonadal heat, continuously hurting spermatogenesis. Therefore, obesity alters the systematic and regional environment crucial for spermatogenesis in testis and sperm maturation in epididymis, and finally results in poor sperm quality including decreased sperm motility, abnormal sperm morphology and acrosome reaction, changed membrane lipids and increased DNA damage. Furthermore, recent studies indicate that epigenetic changes may be a consequence of increased adiposity. A major effort to identify epigenetic determinants of obesity revealed that sperm DNA methylation and non-coding RNA modification are associated with BMI changes and proposed to inherit metabolic comorbidities across generations. This review will explain how obesity-related changes in males to influence sperm function and male fertility as well.