Maternal Melatonin Therapy Rescues Prenatal Dexamethasone and Postnatal High-Fat Diet Induced Programmed Hypertension in Male Rat Offspring

Sex differences in fetal kidney reprogramming: the case in the renin-angiotensin system

During the early stages of the development of the living multiorgan systems, genome modifications other than sequence variation occur that guide cell differentiation and organogenesis. These modifications are known to operate as a fetal programming code during this period, and recent research indicates that there are some tissue-specific codes in organogenesis whose effects may persist after birth until adulthood. Consequently, the events that disrupt the pre-established epigenetic pattern could induce shifts in organ physiology, with implications on health from birth or later in adult life. Chronic kidney disease (CKD) is one of the main causes of mortality worldwide; its etiology is multifactorial, but diabetes, obesity, and hypertension are the main causes of CKD in adults, although there are other risk factors that are mainly associated with an individual's lifestyle. Recent studies suggest that fetal reprogramming in the developing kidney could be implicated in the susceptibility to kidney disease in both childhood and adulthood. Some epigenetic modifications, such as genome methylation status, dysregulation of miRNA, and histone coding alterations in genes related to the regulation of the renin-angiotensin axis, a common denominator in CKD, may have originated during fetal development. This review focuses on epigenetic changes during nephrogenesis and their repercussions on kidney health and disease. In addition, the focus is on the influence of environmental factors during pregnancy, such as maternal metabolic diseases and dietary and metabolic conditions, as well as some sex differences in fetal kidney reprogramming during which dysregulation of the renin-angiotensin system is involved.

Maternal High-Fat Diet Controls Offspring Kidney Health and Disease

A balanced diet during gestation is critical for fetal development, and excessive intake of saturated fats during gestation and lactation is related to an increased risk of offspring kidney disease. Emerging evidence indicates that a maternal high-fat diet influences kidney health and disease of the offspring via so-called renal programming. This review summarizes preclinical research documenting the connection between a maternal high-fat diet during gestation and lactation and offspring kidney disease, as well as the molecular mechanisms behind renal programming, and early-life interventions to offset adverse programming processes. Animal models indicate that offspring kidney health can be improved via perinatal polyunsaturated fatty acid supplementation, gut microbiota changes, and modulation of nutrient-sensing signals. These findings reinforce the significance of a balanced maternal diet for the kidney health of offspring.

Melatonin and Kidney Health: From Fetal Stage to Later Life

Melatonin, an endogenous hormone mainly released at night by the pineal gland, has multifaceted biofunctions. Emerging evidence points to melatonin having a crucial role in kidney health and disease. As the prevalence of chronic kidney disease (CKD) is still rising, a superior strategy to advance global kidney health is needed to not just treat CKD, but prevent it early on. Adult kidney disease can have its origins in early life. This review aims to evaluate the recent literature regarding melatonin's effect on kidney development, its clinical uses in the early stage of life, animal models documenting preventive applications of melatonin on offspring's kidney-related disease, and a thorough summary of therapeutic considerations concerning melatonin supplementation.

The molecular mechanisms in prenatal drug exposure-induced fetal programmed adult cardiovascular disease

The "developmental origins of health and disease" (DOHaD) hypothesis posits that early-life environmental exposures have a lasting impact on individual's health and permanently shape growth, structure, and metabolism. This reprogramming, which results from fetal stress, is believed to contribute to the development of adulthood cardiovascular diseases such as hypertension, coronary artery disease, heart failure, and increased susceptibility to ischemic injuries. Recent studies have shown that prenatal exposure to drugs, such as glucocorticoids, antibiotics, antidepressants, antiepileptics, and other toxins, increases the risk of adult-onset cardiovascular diseases. In addition, observational and animal experimental studies have demonstrated the association between prenatal drug exposure and the programming of cardiovascular disease in the offspring. The molecular mechanisms underlying these effects are still being explored but are thought to involve metabolism dysregulation. This review summarizes the current evidence on the relationship between prenatal drug exposure and the risk of adult cardiovascular disorders. Additionally, we present the latest insights into the molecular mechanisms that lead to programmed cardiovascular phenotypes after prenatal drug exposure.

Maternal Iron Deficiency Programs Rat Offspring Hypertension in Relation to Renin—Angiotensin System and Oxidative Stress

Hypertension is an important public health challenge, affecting up to 30–50% of adults worldwide. Several epidemiological studies indicate that high blood pressure originates in fetal life—the so-called programming effect or developmental origin of hypertension. Iron-deficiency anemia has become one of the most prevalent nutritional problems globally. Previous animal experiments have shown that prenatal iron-deficiency anemia adversely affects offspring hypertension. However, the underlying mechanism remains unclear. We used a maternal low-iron diet Sprague Dawley rat model to study changes in blood pressure, the renal renin-angiotensin system, oxidative stress, inflammation, and sodium transporters in adult male offspring. Our study revealed that 16-week-old male offspring born to mothers with low dietary iron throughout pregnancy and the lactation period had (1) higher blood pressure, (2) increased renal cortex angiotensin II receptor type 1 and angiotensin-converting enzyme abundance, (3) decreased renal cortex angiotensin II receptor type 2 and MAS abundance, and (4) increased renal 8-hydroxy-2′-deoxyguanosine and interleukin-6 abundance. Improving the iron status of pregnant mothers could influence the development of hypertension in their offspring.

Developmental and Early Life Origins of Hypertension: Preventive Aspects of Melatonin

Hypertension represents a major disease burden worldwide. Abundant evidence suggests that hypertension can originate in early life. Adverse programming processes can be prevented by early life intervention-namely, reprogramming-to avoid developing chronic diseases later in life. Melatonin is an endogenously produced hormone with a multifaceted biological function. Although melatonin supplementation has shown benefits for human health, less attention has been paid to exploring its reprogramming effects on the early life origins of hypertension. In this review, first, we discuss the physiological roles of melatonin in pregnancy, fetal development, and the regulation of blood pressure. Then, we summarize the epidemiological and experimental evidence for the early life origins of hypertension. This is followed by a description of the animal models used to examine early melatonin therapy as a reprogramming strategy to protect against the early life origins of hypertension. A deeper understanding of the developmental programming of hypertension and recent advances in early melatonin intervention might provide a path forward in reducing the global burden of hypertension.

Maternal Angiotensin II-Induced Hypertension Sensitizes Postweaning High-Fat Diet-Elicited Hypertensive Response Through Increased Brain Reactivity in Rat Offspring

Background

Prenatal and postnatal insults can induce a physiological state that leaves offspring later in life vulnerable to subsequent challenges (stressors) eliciting cardiometabolic diseases including hypertension. In this study, we investigated whether maternal angiotensin II–induced hypertension in rats sensitizes postweaning high‐fat diet (HFD)‐elicited hypertensive response and whether this is associated with autonomic dysfunction and altered central mechanisms controlling sympathetic tone in offspring.

Methods and Results

When eating a low‐lard‐fat diet, basal mean arterial pressure of male offspring of normotensive or hypertensive dams were comparable. However, HFD feeding significantly increased mean arterial pressure in offspring of normotensive and hypertensive dams, but the elevated mean arterial pressure induced by HFD was greater in offspring of hypertensive dams, which was accompanied by greater sympathetic tone and enhanced pressor responses to centrally administrated angiotensin II or leptin. HFD feeding also produced comparable elevations in cardiac sympathetic activity and plasma levels of angiotensin II, interleukin‐6, and leptin in offspring of normotensive and hypertensive dams. Reverse transcriptase polymerase chain reaction analyses in key forebrain regions implicated in the control of sympathetic tone and blood pressure indicated that HFD feeding led to greater increases in mRNA expression of leptin, several components of the renin‐angiotensin system and proinflammatory cytokines in offspring of hypertensive dams when compared with offspring of normotensive dams.

Conclusions

The results indicate that maternal hypertension sensitized male adult offspring to HFD‐induced hypertension. Increased expression of renin‐angiotensin system components and proinflammatory cytokines, elevated brain reactivity to pressor stimuli, and augmented sympathetic drive to the cardiovascular system likely contributed.

Melatonin Prevents Chronic Kidney Disease-Induced Hypertension in Young Rat Treated with Adenine: Implications of Gut Microbiota-Derived Metabolites

Melatonin, a signaling hormone with pleiotropic biofunctions, has shown health benefits. Trimethylamine-N-oxide (TMAO) and asymmetric dimethylarginine (ADMA) are uremic toxins involved in the development of hypertension. TMAO originates from trimethylamine (TMA), a gut microbial product. ADMA is an endogenous nitric oxide (NO) synthase inhibitor. We examined whether melatonin therapy could prevent hypertension and kidney disease by mediating gut microbiota-derived metabolites and the NO pathway using an adenine-induced chronic kidney disease (CKD) young rat model. Six-week-old young Sprague Dawley rats of both sexes were fed a regular diet (C group), a diet supplemented with 0.5% adenine (CKD group), or adenine plus 0.01% melatonin in their drinking water (CKD + M group) for three weeks (N = 8/group). Adenine-fed rats developed renal dysfunction, hypertension, renal hypertrophy and increased uremic toxin levels of TMAO and ADMA. Melatonin therapy prevented hypertension in both sexes and attenuated kidney injury in males. Melatonin reversed the changes to the plasma TMAO-to-TMA ratio induced by CKD in both sexes. Besides, the protective effects of melatonin were associated with restoration of gut microbiota alterations, including increased α-diversity, and enhancement of the abundance of the phylum Proteobacteria and the genus Roseburia in male rats. Melatonin therapy also partially prevented the increases in ADMA in male CKD rats. Melatonin sex-specifically protected young rats against hypertension and kidney injury induced by CKD. The results of this study contribute toward a greater understanding of the interaction between melatonin, gut microbiota-derived metabolites, and the NO pathway that is behind CKD, which will help to prevent CKD-related disorders in children.

Maternal effects in mammals: Broadening our understanding of offspring programming

The perinatal period is a sensitive time in mammalian development that can have long-lasting consequences on offspring phenotype via maternal effects. Maternal effects have been most intensively studied with respect to two major conditions: maternal diet and maternal stress. In this review, we shift the focus by discussing five major additional maternal cues and their influence on offspring phenotype: maternal androgen levels, photoperiod (melatonin), microbiome, immune regulation, and milk composition. We present the key findings for each of these topics in mammals, their mechanisms of action, and how they interact with each other and with the maternal influences of diet and stress. We explore their impacts in the contexts of both predictive adaptive responses and the developmental origins of disease, identify knowledge gaps and research opportunities in the field, and place a particular emphasis on the application and consideration of these effects in non-model species and natural ecological systems.

Time-restricted feeding in dark phase of circadian cycle and/or westernized diet cause mixed hyperlipidemia in rats

Introduction

Background: the dietary pattern that characterizes western diet is strongly associated with metabolic diseases and excess weight, as well as chronic illnesses. Misaligned feeding schedules can lead to or aggravate the development of such conditions. Aim: this study evaluated the influence of dietary composition and/or time-restricted feeding on the anthropometric and biochemical profile of adult rats. Methods: forty male rats, at 60 days of life, were divided into the following groups: Control (C), Restricted Control (RC), Westernized (W), and Restricted Westernized (RW). Results: westernized groups, in spite of a low energy intake (C = 5399 ± 401.2 kcal; RC = 4279.0 ± 476.2 kcal; W = 4302 ± 619.8 kcal; RW = 4081.0 ± 404.4 kcal, p < 0.001), had a higher body weight (C = 404.6 ± 39.1 g; RC = 335.1 ± 36.5 g; W = 488.9 ± 51.2 g; RW = 438.8 ± 36.5 g, p < 0.001) as compared to their paired controls (RC and C) - around 30 % and 20 % more for RW and W, respectively. The westernized diet caused glucose intolerance and mixed hyperlipidemia, characterized by higher concentrations of cholesterol (C = 40.8 ± 7.4 mg/dL; RC = 76.7 ± 10.8 mg/dL; W = 61.3 ± 20.2 mg/dL; RW = 42.2 ± 8.2 mg/dL), LDLc (C = 17.4 ± 7.5 mg/dL; RC = 38.8 ± 7.2 mg/dL ; W = 45.3 ± 15.8 mg/dL; RW = 11.0 ± 5.8 mg/dL), and triacylglycerol (C = 45.2 ± 15.0 mg/dL; RC = 73.2 ± 21.5 mg/dL ; W = 83.6 ± 23.4 mg/dL; RW = 57.5 ± 13.6 mg/dL) in the serum (p < 0.05). Conclusion: the effect of time-restricted feeding on body weight was strongly dependent on diet composition. The glucose tolerance test showed an influence of the circadian cycle phase. Mixed hyperlipidemia varied according to the presence of westernized diet and/or time-restricted food.

Developmental Origins of Kidney Disease: Why Oxidative Stress Matters?

The "developmental origins of health and disease" theory indicates that many adult-onset diseases can originate in the earliest stages of life. The developing kidney has emerged as being particularly vulnerable to adverse in utero conditions leading to morphological and functional changes, namely renal programming. Emerging evidence indicates oxidative stress, an imbalance between reactive oxygen/nitrogen species (ROS/RNS) and antioxidant systems, plays a pathogenetic role in the developmental programming of kidney disease. Conversely, perinatal use of antioxidants has been implemented to reverse programming processes and prevent adult-onset diseases. We have termed this reprogramming. The focus of this review is twofold: (1) To summarize the current knowledge on oxidative stress implicated in renal programming and kidney disease of developmental origins; and (2) to provide an overview of reprogramming effects of perinatal antioxidant therapy on renal programming and how this may prevent adult-onset kidney disease. Although early-life oxidative stress is implicated in mediating renal programming and adverse offspring renal outcomes, and animal models provide promising results to allow perinatal antioxidants applied as potential reprogramming interventions, it is still awaiting clinical translation. This presents exciting new challenges and areas for future research.

Developmental Programming and Reprogramming of Hypertension and Kidney Disease: Impact of Tryptophan Metabolism

The concept that hypertension and chronic kidney disease (CKD) originate in early life has emerged recently. During pregnancy, tryptophan is crucial for maternal protein synthesis and fetal development. On one hand, impaired tryptophan metabolic pathway in pregnancy impacts fetal programming, resulting in the developmental programming of hypertension and kidney disease in adult offspring. On the other hand, tryptophan-related interventions might serve as reprogramming strategies to prevent a disease from occurring. In the present review, we aim to summarize (1) the three major tryptophan metabolic pathways, (2) the impact of tryptophan metabolism in pregnancy, (3) the interplay occurring between tryptophan metabolites and gut microbiota on the production of uremic toxins, (4) the role of tryptophan-derived metabolites-induced hypertension and CKD of developmental origin, (5) the therapeutic options in pregnancy that could aid in reprogramming adverse effects to protect offspring against hypertension and CKD, and (6) possible mechanisms linking tryptophan metabolism to developmental programming of hypertension and kidney disease.

Early Origins of Hypertension: Should Prevention Start Before Birth Using Natural Antioxidants?

Hypertension may originate in early life. Reactive oxygen species (ROS) generated due to the exposure of adverse in utero conditions causes developmental programming of hypertension. These excessive ROS can be antagonized by molecules which are antioxidants. Prenatal use of natural antioxidants may reverse programming processes and prevent hypertension of developmental origin. In the current review, firstly we document data on the impact of oxidative stress in hypertension of developmental origin. This will be followed by effective natural antioxidants uses starting before birth to prevent hypertension of developmental origin in animal models. It will also discuss evidence for the common mechanisms underlying developmental hypertension and beneficial effects of natural antioxidant interventions used as reprogramming strategies. A better understanding of the reprogramming effects of natural antioxidants and their interactions with common mechanisms underlying developmental hypertension is essential. Therefore, pregnant mothers and their children can benefit from natural antioxidant supplementation during pregnancy in order to reduce their risk for hypertension later in life.

Melatonin attenuates hypertension and oxidative stress in a rat model of L-NAME-induced gestational hypertension

Preeclampsia is a life-threatening multiorgan systemic disease with manifestations including gestational hypertension, oxidative stress, and vascular dysfunction. We aimed to evaluate the therapeutic effects of melatonin on an L-NAME (NLG-nitro-l-arginine methyl ester)-induced rat preeclampsia model. During gestation, L-NAME was added to drinking water at 50 mg/kg/day from gestation day (GD) 8. Rats received the combination of L-NAME with melatonin (10 mg/kg/day), or aspirin (1.5 mg/kg/day), and rats that received only L-NAME or no treatments were used as controls. Aspirin was mixed with rodent chow and melatonin was administered intraperitoneally. Blood pressure and urine protein content were monitored every 3 days. On GD19, blood samples were collected for biochemical analysis. Compared to untreated L-NAME rats, melatonin led to markedly lowered blood pressure and urine protein content, and recovery in the fetus alive ratio, fetal weight, and the fetal weight/placental weight ratio. Compared to untreated L-NAME rats, plasma antioxidant capacity and plasma malondialdehyde were increased and decreased by melatonin, respectively, in L-NAME rats. Melatonin treatment also reduced sFlt-1, increased PlGF, and decreased the sFlt-1/PlGF ratio. In the placenta, melatonin also reduced sFlt-1 levels and increased Nrf2, PlGF, and HO-1 levels. We have demonstrated in a rat model of preeclampsia that melatonin exerts significant protective effects through lowering blood pressure and reducing oxidative stress.

Effects of Maternal Resveratrol on Maternal High-Fat Diet/Obesity with or without Postnatal High-Fat Diet

To examine the effects of maternal resveratrol in rats borne to dams with gestational high-fat diet (HFD)/obesity with or without postnatal high-fat diet. We first tested the effects of maternal resveratrol intake on placenta and male fetus brain in rats borne to dams with gestational HFD/obesity. Then, we assessed the possible priming effect of a subsequent insult, male offspring were weaned onto either a rat chow or a HFD. Spatial learning and memory were assessed by Morris water maze test. Blood pressure and peripheral insulin resistance were examined. Maternal HFD/obesity decreased adiponectin, phosphorylation alpha serine/threonine-protein kinase (pAKT), sirtuin 1 (SIRT1), and brain-derived neurotrophic factor (BDNF) in rat placenta, male fetal brain, and adult male offspring dorsal hippocampus. Maternal resveratrol treatment restored adiponectin, pAKT, and BDNF in fetal brain. It also reduced body weight, peripheral insulin resistance, increased blood pressure, and alleviated cognitive impairment in adult male offspring with combined maternal HFD and postnatal HFD. Maternal resveratrol treatment restored hippocampal pAKT and BDNF in rats with combined maternal HFD and postnatal HFD in adult male offspring dorsal hippocampus. Maternal resveratrol intake protects the fetal brain in the context of maternal HFD/obesity. It effectively reduced the synergistic effects of maternal HFD/obesity and postnatal HFD on metabolic disturbances and cognitive impairment in adult male offspring. Our data suggest that maternal resveratrol intake may serve as an effective therapeutic strategy in the context of maternal HFD/obesity.

Light and Circadian Signaling Pathway in Pregnancy: Programming of Adult Health and Disease

Light is a crucial environmental signal that affects elements of human health, including the entrainment of circadian rhythms. A suboptimal environment during pregnancy can increase the risk of offspring developing a wide range of chronic diseases in later life. Circadian rhythm disruption in pregnant women may have deleterious consequences for their progeny. In the modern world, maternal chronodisruption can be caused by shift work, jet travel across time zones, mistimed eating, and excessive artificial light exposure at night. However, the impact of maternal chronodisruption on the developmental programming of various chronic diseases remains largely unknown. In this review, we outline the impact of light, the circadian clock, and circadian signaling pathways in pregnancy and fetal development. Additionally, we show how to induce maternal chronodisruption in animal models, examine emerging research demonstrating long-term negative implications for offspring health following maternal chronodisruption, and summarize current evidence related to light and circadian signaling pathway targeted therapies in pregnancy to prevent the development of chronic diseases in offspring.

Perinatal Use of Melatonin for Offspring Health: Focus on Cardiovascular and Neurological Diseases

Cardiovascular and neurological diseases can originate in early life. Melatonin, a biologically active substance, acts as a pleiotropic hormone essential for pregnancy and fetal development. Maternal melatonin can easily pass the placenta and provide photoperiodic signals to the fetus. Though melatonin uses in pregnant or lactating women have not yet been recommended, there is a growing body of evidence from animal studies in support of melatonin as a reprogramming strategy to prevent the developmental programming of cardiovascular and neurological diseases. Here, we review several key themes in melatonin use in pregnancy and lactation within offspring health and disease. We have particularly focused on the following areas: the pathophysiological roles of melatonin in pregnancy, lactation, and fetal development; clinical uses of melatonin in fetal and neonatal diseases; experimental evidence supporting melatonin as a reprogramming therapy to prevent cardiovascular and neurological diseases; and reprogramming mechanisms of melatonin within developmental programming. The targeting of melatonin uses in pregnancy and lactation will be valuable in the prevention of various adult chronic diseases in later life, and especially cardiovascular and neurological diseases.

Protection of Male Rat Offspring against Hypertension Programmed by Prenatal Dexamethasone Administration and Postnatal High-Fat Diet with the Nrf2 Activator Dimethyl Fumarate during Pregnancy

Hypertension can originate from early-life exposure to oxidative stress. As reported, dimethyl fumarate (DMF) activates nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and protects against oxidative stress damage. We examined whether maternal DMF therapy protects adult offspring against hypertension programmed by prenatal dexamethasone (DEX) and postnatal high-fat (HF) diet exposure. We examined male Sprague Dawley rat offspring at 4 months of age from five groups (n = 11-13/group): control, DEX (0.1mg/kg i.p. from gestational day 16 to 22), HF (D12331 diet from weaning to 16 weeks of age), DEX+HF, and DEX+HF+DMF (50mg/kg/day via gastric gavage for 3 weeks during pregnancy). Maternal DMF therapy prevented male offspring against hypertension programmed by combined DEX and HF exposures. The protective effects of maternal DMF include reduced oxidative stress, decreased plasma asymmetric dimethylarginine (ADMA) levels, downregulated the renin-angiotensin system (i.e. Ren, Agt, Ace, and Agtr1a), increased renal protein levels of certain nutrient-sensing signals, and promoted autophagy. In conclusion, maternal Nrf2 activation by DMF protects male adult offspring against hypertension programmed by combined DEX and HF exposures. Our results cast a new light on the therapeutic potential of targeting Nrf2 signaling pathway as reprogramming strategies to prevent programmed hypertension in children exposed to antenatal corticosteroids and postnatally excessive consumption of fat.

Resveratrol prevents combined prenatal NG-nitro-L-arginine-methyl ester (L-NAME) treatment plus postnatal high-fat diet induced programmed hypertension in adult rat offspring: interplay between nutrient-sensing signals, oxidative stress and gut microbiota

Oxidative stress, nutrient-sensing signals, high-fat (HF) intake and dysbiosis of gut microbiota are involved in the development of hypertension, a disorder that can originate in early life. We examined whether postnatal HF diet can aggravate maternal N^G-nitro-L-arginine-methyl ester (L-NAME) treatment-induced programmed hypertension and whether resveratrol therapy can prevent it. Pregnant Sprague-Dawley rats received L-NAME administration at 60 mg/kg/day subcutaneously during pregnancy alone, or with additional resveratrol (R) 50 mg/L in drinking water during the pregnancy and lactation. The offspring were onto either regular chow or HF diet (D12331) from weaning to 16 weeks of age. Male offspring rats were assigned to five groups (N=8/group): control, L-NAME, HF, L-NAME+HF and L-NAME+HF + R at weaning at 3 weeks of age. Rats were sacrificed at 16 weeks of age. We observed that postnatal HF diet exacerbates maternal L-NAME treatment-induced programmed hypertension in male adult offspring, which resveratrol attenuated. Combined L-LAME and HF diet-induced hypertension is related to increased oxidative stress, inhibiting AMP-activated protein kinase (AMPK)/ peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) pathway and altered gut microbiota compositions. L-NAME+HF caused an increase of the Firmicutes to Bacteroidetes ratio, which resveratrol therapy prevented. Additionally, the abundances of phylum Verrucomicrobia and genus Akkermansia were amplified by resveratrol therapy. Conclusively, our data highlighted the interactions between maternal NO deficiency, HF diet, AMPK/PGC-1α pathway and gut microbiota in which the blood pressure of adult offspring can be modified by resveratrol. Resveratrol might be a useful reprogramming strategy to prevent L-NAME and HF diet-induced hypertension of developmental origin.

Obesity programmed by prenatal dexamethasone and postnatal high-fat diet leads to distinct alterations in nutrition sensory signals and circadian-clock genes in visceral adipose tissue

BACKGROUND

Prenatal dexamethasone treatment has been shown to enhance the susceptibility of offspring to postnatal high-fat (HF) diet-induced programmed obesity. We investigated the metabolic phenotypes, nutrient-sensing signal and circadian-clock genes in adipose tissue that are programmed by prenatal dexamethasone exposure and postnatal HF diet.

METHODS

Male offspring of Sprague-Dawley rats were divided into four experimental groups: normal diet, prenatal dexamethasone exposure, postnatal HF diet, and prenatal dexamethasone plus postnatal HF diet. Postnatal HF diet was prescribed from weaning to 6 months of age.

RESULTS

Prenatal dexamethasone and postnatal HF diet exerted synergistic effects on body weight and visceral adiposity, whereas prenatal dexamethasone and postnatal HF diet altered the metabolic profile and caused leptin dysregulation. Prenatal dexamethasone and postnatal HF diet distinctly influenced nutrient-sensing molecules and circadian-clock genes in adipose tissue. The mRNA expression of mTOR, AMPK-α2, PPAR-α, and PPAR-γ was suppressed by prenatal dexamethasone but enhanced by postnatal HF diet.

CONCLUSION

Prenatal dexamethasone and postnatal HF treatment cause dysregulation of nutrient-sensing molecules and circadian-clock genes in visceral adipose tissue. Characterizing altered nutrient-sensing molecules and circadian-clock genes has potential therapeutic relevance with respect to the pathogenesis and treatment of prenatal stress and postnatal HF diet-related metabolic disorders.

Epigenetic regulation of carnitine palmitoyltransferase 1 (Cpt1a) by high fat diet

Carnitine palmitoyltransferase 1 (Cpt1a) is a rate-limiting enzyme that mediates the transport of fatty acids into the mitochondria for subsequent beta-oxidation. The objective of this study was to uncover how diet mediates the transcriptional regulation of Cpt1a. Pregnant Sprague Dawley rats were exposed to either a high-fat (HF) or low-fat control diet during gestation and lactation. At weaning, male offspring received either a HF or control diet, creating 4 groups: lifelong control diet (C/C; n = 12), perinatal HF diet (HF/C; n = 9), post-weaning HF diet (C/HF; n = 10), and lifelong HF diet (HF/HF; n = 10). Only HF/HF animals had higher hepatic Cpt1a mRNA expression than C/C. Epigenetic analysis revealed reduced DNA methylation (DNAMe) and increased histone 3 lysine 4 dimethylation (H3K4Me2) upstream and within the promoter of Cpt1a in the HF/HF group. This was accompanied by increased peroxisome proliferator activated receptor alpha (PPARα) and CCAAT/enhancer binding protein beta (C/EBPβ) binding directly downstream of the Cpt1a transcription start site within the first intron. Findings were confirmed in rat hepatoma H4IIEC3 cells treated with non-esterified fatty acid (NEFA). After 12 h of NEFA treatment, there was an enrichment of SWI/SNF related matrix associated actin dependent regulator of chromatin subfamily D member 1 (BAF60a or SMARCD1) in the first intron of Cpt1a. We conclude that dietary fat elevates hepatic Cpt1a expression via a highly coordinated transcriptional mechanism involving increased H3K4Me2, reduced DNAMe, and recruitment of C/EBPβ, PPARα, PGC1α, and BAF60a to the gene.

Postnatal high-fat diet sex-specifically exacerbates prenatal dexamethasone-induced hypertension: Mass spectrometry-based quantitative proteomic approach

Hypertension can originate from pre- and post-natal insults. High-fat (HF) diet and prenatal dexamethasone (DEX) exposure are both involved in hypertension of developmental origins. We examined whether postnatal HF diet sex-specifically increases the vulnerability to prenatal DEX exposure-induced programmed hypertension in adult offspring. Additionally, we sought to identify candidate proteins involved in programmed hypertension through a mass spectrometry-based quantitative proteomic approach. Male and female offspring were studied separately: control, DEX, HF, and DEX + HF (n=8/group). Pregnant Sprague-Dawley rats received dexamethasone (0.1 mg/kg body weight) or vesicle from gestational day 16-22. Offspring received high-fat diet (D12331, Research Diets) or regular diet from weaning to 4 months of age. Rats were sacrificed at 4 months of age. We found that postnatal HF diet increased vulnerability of prenatal DEX-induced hypertension in male but not in female adult offspring. Additionally, HF and DEX elicited renal programming in a sex-specific fashion. In males, DEX + HF increased renal parvalbumin (PVALB) and carbonic anhydrase III (CA III) protein levels. While prenatal DEX down-regulated PVALB and CA III protein abundance in female offspring kidneys. Moreover, DEX + HF increased renal protein level of type 3 sodium hydrogen exchanger (NHE3) in males but not in females. In conclusion, postnatal HF diet and prenatal DEX exposure synergistically induced programmed hypertension in male-only offspring. DEX + HF induced sex-specific alterations of protein profiles in offspring kidneys. By identifying candidate proteins underlying sex-specific mechanisms, our results could lead to novel offspring sex-specific interventions to prevent hypertension induced by antenatal corticosteroids and postnatal HF intake in both sexes.

Combined maternal and postnatal high-fat diet leads to metabolic syndrome and is effectively reversed by resveratrol: a multiple-organ study

This study aimed to study the impact of a combination of maternal and post-weaning high-fat diets and whether resveratrol was beneficial. Sprague-Dawley dams were fed either chow or a high-fat diet, before mating, during pregnancy, and into lactation. At weaning, their offspring were randomly fed chow or a high-fat diet. Four experimental groups were generated: CC (maternal/postnatal chow diet), HC (maternal high-fat/postnatal chow diet), CH (maternal chow/postnatal high-fat diet), and HH (maternal/postnatal high-fat diet). A fifth group consisted of HH plus resveratrol. The 4 month-old offspring of HH group had higher body weight, higher levels of plasma triglycerides, leptin, angiotensin I and angiotensin II and abnormal intraperitoneal glucose tolerance test results, which fulfilled the features of metabolic syndrome. The dysregulation of the renin-angiotensin system was seen in multiple organs. Sirtuin 1 expression/abundance was reduced by a maternal/postnatal high-fat diet, in all the organs examined. Resveratrol ameliorated most of the features of metabolic syndrome and molecular alterations. The administration of a high-fat diet in both periods showed interactive metabolic effects in the plasma and many organs. Our results suggest that a maternal high-fat diet sensitizes offspring to the adverse effects of subsequent high-fat intake on multiple organs.

Prenatal dexamethasone and postnatal high-fat diet have a synergistic effect of elevating blood pressure through a distinct programming mechanism of systemic and adipose renin-angiotensin systems

Background

Hypertension may result from high-fat (HF) diet induced-obesity and overexposure to glucocorticoids in utero. Recent studies demonstrated the potent contribution of adipose tissue’s renin-angiotensin system (RAS) to systemic RAS, which plays a key role in regulating blood pressure (BP). In this study, we investigated the effects of prenatal dexamethasone (DEX) exposure and postnatal HF diet on RAS of adipose tissue.

Methods

RAS and BP of 6-month old rats exposed to prenatal DEX and/or postnatal HF diet were examined.

Results

Prenatal DEX plus postnatal HF exerted a synergistic effect on systolic BP. Prenatal DEX exposure suppressed plasma angiotensin (ANG) I and ANG II, whereas postnatal HF suppressed plasma ANG-(1–7) level. Prenatal DEX increased prorenin receptor and renin levels, but suppressed angiotensinogen (AGT) and angiotensin-converting-enzyme 1 (ACE1) mRNA expressions in adipose tissue. Postnatal HF increased AGT mRNA expression, but suppressed prorenin receptor, renin, ACE2, ANG II type 2 receptor (AT2R), and Mas receptor (MasR) mRNA expression levels.

Conclusions

Prenatal GC exposure altered the ACE1/ANG II/ANG II type 1 receptor (AT1R) axis, whereas postnatal HF negatively impacted the ACE2/ANG-(1–7)/MasR axis. Prenatal DEX exposure and postnatal HF synergistically elevated BP through a distinct programming mechanism of systemic and adipose RAS. Adipose RAS might be a target for precise hypertension treatment.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0701-0) contains supplementary material, which is available to authorized users.

Maternal High Fructose Intake Increases the Vulnerability to Post-Weaning High-Fat Diet-Induced Programmed Hypertension in Male Offspring

Widespread consumption of high-fructose and high-fat diets relates to the global epidemic of hypertension. Hypertension may originate from early life by a combination of prenatal and postnatal nutritional insults. We examined whether maternal high-fructose diet increases vulnerability to post-weaning high-fructose or high-fat diets induced hypertension in adult offspring and determined the underlying mechanisms. Pregnant Sprague-Dawley rats received regular chow (ND) or chow supplemented with 60% fructose (HFR) during the entire pregnancy and lactation periods. Male offspring were onto either the regular chow, 60% fructose, or high-fat diet (HFA) from weaning to 12 weeks of age and assigned to four groups: ND/ND, HFR/ND, HFR/HFR, and HFR/HFA. Maternal high-fructose diet exacerbates post-weaning high-fat diet-induced programmed hypertension. Post-weaning high-fructose and high-fat diets similarly reduced Sirt4, Prkaa2, Prkag2, Ppara, Pparb, and Ppargc1a mRNA expression in offspring kidneys exposed to maternal high-fructose intake. Additionally, post-weaning high-fat diet significantly reduced renal mRNA levels of Ulk1, Atg5, and Nrf2 and induced greater oxidative stress than did high-fructose diet. Although maternal high-fructose intake increases soluble epoxide hydrolase (SEH) expression in the kidney, which was restored by post-weaning high-fructose and high-fat diets. Maternal high-fructose diet programs differential vulnerability to developing hypertension in male offspring in response to post-weaning high-fructose and high-fat diets. Our data implicated that specific therapy targeting on nutrient sensing signals, oxidative stress, and SEH may be a promising approach to prevent hypertension in children and mothers exposed to high-fructose and high-fat consumption.

Biochemical basis for pharmacological intervention as a reprogramming strategy against hypertension and kidney disease of developmental origin

The concept of "developmental origins of health and disease" (DOHaD) stipulates that both hypertension and kidney disease may take origin from early-life insults. The DOHaD concept also offers reprogramming strategies aiming at shifting therapeutic interventions from adulthood to early life, even before clinical symptoms are evident. Based on those two concepts, this review will present the evidence for the existence of, and the programming mechanisms in, kidney developmental programming that may lead to hypertension and kidney disease. This will be followed by potential pharmacological interventions that may serve as a reprogramming strategy to counter the rising epidemic of hypertension and kidney disease. We point out that before patients could benefit from this strategy, the most pressing issue is for the growing body of evidence from animal studies in support of pharmacological intervention as a reprogramming strategy to long-term protect against hypertension and kidney disease of developmental origins to be validated clinically and the critical window, drug dose, dosing regimen, and therapeutic duration identified.

A maternal high-fat diet during pregnancy and lactation, in addition to a postnatal high-fat diet, leads to metabolic syndrome with spatial learning and memory deficits: beneficial effects of resveratrol

We tested the hypothesis that high-fat diet consumption during pregnancy, lactation, and/or post weaning, altered the expression of molecular mediators involved in hippocampal synaptic efficacy and impaired spatial learning and memory in adulthood. The beneficial effect of resveratrol was assessed. Dams were fed a rat chow diet or a high-fat diet before mating, during pregnancy, and throughout lactation. Offspring were weaned onto either a rat chow or a high-fat diet. Four experimental groups were generated, namely CC, HC, CH, and HH (maternal chow diet or high-fat diet; postnatal chow diet or high-fat diet). A fifth group fed with HH plus resveratrol (HHR) was generated. Morris water maze test was used to evaluate spatial learning and memory. Blood pressure and IPGTT was measured to assess insulin resistance. Dorsal hippocampal expression of certain biochemical molecules, including sirtuin 1, ERK, PPARγ, adiponectin, and BDNF were measured. Rats in HH group showed impaired spatial memory, which was partly restored by the administration of resveratrol. Rats in HH group also showed impaired glucose tolerance and increased blood pressure, all of which was rescued by resveratrol administration. Additionally, SIRT1, phospho-ERK1/2, and phospho-PPARγ, adiponectin and BDNF were all dysregulated in rats placed in HH group; administration of resveratrol restored the expression and regulation of these molecules. Overall, our results suggest that maternal high-fat diet during pregnancy and/or lactation sensitizes the offspring to the adverse effects of a subsequent high-fat diet on hippocampal function; however, administration of resveratrol is demonstrated to be beneficial in rescuing these effects.

Increased susceptibility of post-weaning rats on high-fat diet to metabolic syndrome

The present study aimed to examine the effects of the types of high-calorie diets (high-fat and high-fat-high-sucrose diets) and two different developmental stages (post-weaning and young adult) on the induction of metabolic syndrome. Male, post-weaning and adult (3- and 8-week old, respectively) Sprague Dawley rats were given control, high-fat (60% kcal), and high-fat-high-sucrose (60% kcal fat + 30% sucrose water) diets for eight weeks (n = 6 to 7 per group). Physical, biochemical, and transcriptional changes as well as liver histology were noted. Post-weaning rats had higher weight gain, abdominal fat mass, fasting glucose, high density lipoprotein cholesterol, faster hypertension onset, but lower circulating advanced glycation end products compared to adult rats. This is accompanied by upregulation of peroxisome proliferator-activated receptor (PPAR) α and γ in the liver and receptor for advanced glycation end products (RAGE) in the visceral adipose tissue. Post-weaning rats on high-fat diet manifested all phenotypes of metabolic syndrome and increased hepatic steatosis, which are linked to increased hepatic and adipocyte PPARγ expression. Adult rats on high-fat-high-sucrose diet merely became obese and hypertensive within the same treatment duration. Thus, it is more effective and less time-consuming to induce metabolic syndrome in male post-weaning rats with high-fat diet compared to young adult rats. As male rats were selectively included into the study, the results may not be generalisable to all post-weaning rats and further investigation on female rats is required.

Resveratrol prevents the combined maternal plus postweaning high-fat-diets-induced hypertension in male offspring

Maternal high-fat (HF) diet is believed to induce oxidative stress and activate nutrient-sensing signals, which increase the risk of adult offspring to develop hypertension. We investigated whether resveratrol prevents the combined maternal plus postweaning HF-diets-induced hypertension in adult male offspring, with a focus on the kidney. Female Sprague-Dawley rats received either a normal diet (ND) or HF diet (D12331, Research Diets) for 5 weeks before mating and during gestation and lactation. The male offspring were placed on either the ND or HF diet from weaning to 4 months of age, resulting in four experimental groups (maternal diet/postweaning diet; n=8-10/group): ND/ND, ND/HF, HF/ND and HF/HF. Another group of HF/HF rats (n=10) was treated with 0.5% resveratrol in drinking water between 2 and 4 months of age (HF/HF+R). Rats were killed at 4 months of age. We found that HF/HF-induced hypertension in adult offspring was prevented by resveratrol. Resveratrol mediated its protective effect on HF/HF-induced hypertension in the kidneys of male offspring by diminishing oxidative stress; reducing renal asymmetric dimethylarginine levels; mediating the renin-angiotensin system (RAS) in favor of vasodilatation; restoring nutrient-sensing pathways via increased levels of silent information regulator transcript 1 (SIRT1), AMP-activated protein kinase 2α and peroxisome proliferator-activated receptor gamma coactivator 1-α; and inducing autophagy. Our data implicated an association between oxidative stress, RAS, nitric oxide, and nutrient-sensing signals in HF/HF-induced hypertension. Resveratrol, acting as an antioxidant as well as a SIRT1 activator, might be a therapeutic approach for hypertension.

Detrimental effect of maternal and post-weaning high-fat diet on the reproductive function in the adult female offspring rat: roles of insulin-like growth factor 2 and the ovarian circadian clock

PURPOSE

We evaluate the impact of maternal and post-weaning high-fat (HF) diet on ovarian follicular population, steroidogenesis, and gene expression with a focus on the circadian clock system and insulin-like growth factor 2 (Igf2) in adult offspring ovaries, and to elucidate whether a maternal and post-weaning diet confers similar risks.

METHODS

Virgin Sprague-Dawley rats were fed with normal chow (C) diet or HF diet for 5 weeks before mating, during gestation, and lactation. Female offspring were fed with the C or HF diet from weaning to 6 months of age, resulting in four study groups (n = 6 per group): C/C, C/HF, HF/C, and HF/HF.

RESULTS

Ovaries from offspring exposed to post-weaning HF diet (i.e., the C/HF and HF/HF groups) had a decrease in small follicle numbers, but with similar numbers of antral follicles and corpora lutea. Offspring from HF-fed dams (i.e., the HF/C and HF/HF groups) had increased plasma estradiol concentrations and decreased luteinizing hormone levels at 6 months of age. In addition, Igf2 and each of the circadian rhythm core genes Clock, Per1, Per2, and Per3 were increased in the ovaries of offspring exposed to maternal HF diet (both HF/C and HF/HF groups).

CONCLUSIONS

Maternal and post-weaning HF diet programs the reproductive profile of the female offspring in adult life through different manners. Post-weaning HF intake resulted in the reduction of small follicles in adulthood, whereas maternal HF diet had long-term deleterious consequences on female offspring steroidogenesis and coincided with alteration of the upregulation of the imprinted gene Igf2 and changes in ovarian circadian rhythms.

High Fat Diets Sex-Specifically Affect the Renal Transcriptome and Program Obesity, Kidney Injury, and Hypertension in the Offspring

Obesity and related disorders have increased concurrently with an increased consumption of saturated fatty acids. We examined whether post-weaning high fat (HF) diet would exacerbate offspring vulnerability to maternal HF-induced programmed hypertension and kidney disease sex-specifically, with a focus on the kidney. Next, we aimed to elucidate the gene–diet interactions that contribute to maternal HF-induced renal programming using the next generation RNA sequencing (NGS) technology. Female Sprague-Dawley rats received either a normal diet (ND) or HF diet (D12331, Research Diets) for five weeks before the delivery. The offspring of both sexes were put on either the ND or HF diet from weaning to six months of age, resulting in four groups of each sex (maternal diet/post-weaning diet; n = 5–7/group): ND/ND, ND/HF, HF/ND, and HF/HF. Post-weaning HF diet increased bodyweights of both ND/HF and HF/HF animals from three to six months only in males. Post-weaning HF diet increased systolic blood pressure in male and female offspring, irrespective of whether they were exposed to maternal HF or not. Male HF/HF offspring showed greater degrees of glomerular and tubular injury compared to the ND/ND group. Our NGS data showed that maternal HF diet significantly altered renal transcriptome with female offspring being more HF-sensitive. HF diet induced hypertension and renal injury are associated with oxidative stress, activation of renin-angiotensin system, and dysregulated sodium transporters and circadian clock. Post-weaning HF diet sex-specifically exacerbates the development of obesity, kidney injury, but not hypertension programmed by maternal HF intake. Better understanding of the sex-dependent mechanisms that underlie HF-induced renal programming will help develop a novel personalized dietary intervention to prevent obesity and related disorders.

Developmental Programming of Adult Disease: Reprogramming by Melatonin?

Adult-onset chronic non-communicable diseases (NCDs) can originate from early life through so-called the "developmental origins of health and disease" (DOHaD) or "developmental programming". The DOHaD concept offers the "reprogramming" strategy to shift the treatment from adulthood to early life, before clinical disease is apparent. Melatonin, an endogenous indoleamine produced by the pineal gland, has pleiotropic bioactivities those are beneficial in a variety of human diseases. Emerging evidence support that melatonin is closely inter-related to other proposed mechanisms contributing to the developmental programming of a variety of chronic NCDs. Recent animal studies have begun to unravel the multifunctional roles of melatonin in many experimental models of developmental programming. Even though some progress has been made in research on melatonin as a reprogramming strategy to prevent DOHaD-related NCDs, future human studies should aim at filling the translational gap between animal models and clinical trials. Here, we review several key themes on the reprogramming effects of melatonin in DOHaD research. We have particularly focused on the following areas: mechanisms of developmental programming; the interrelationship between melatonin and mechanisms underlying developmental programming; pathophysiological roles of melatonin in pregnancy and fetal development; and insight provided by animal models to support melatonin as a reprogramming therapy. Rates of NCDs are increasing faster than anticipated all over the world. Hence, there is an urgent need to understand reprogramming mechanisms of melatonin and to translate experimental research into clinical practice for halting a growing list of DOHaD-related NCDs.

Sex differences in renal transcriptome and programmed hypertension in offspring exposed to prenatal dexamethasone

Glucocorticoids, predominantly dexamethasone (DEX), are widely used to reduce the risk of prematurity-related chronic lung disease. However, prenatal DEX treatment links to adverse effects in later life, including hypertension. Given that sex differences exist in the blood pressure (BP) control, and that renal transcriptome is sex-specific, thus we intended to elucidate whether prenatal DEX-induced programmed hypertension is in a sex-specific manner and identify candidate genes and pathways using the whole-genome RNA next-generation sequencing (NGS) approach. Offspring were assigned to 4 groups (n=7-8/group): male control (MC), female control (FC), male DEX (MD), and female DEX (FD). Dexamethasone (0.1mg/kg body weight) or vehicle was intraperitoneally administered to pregnant SD rats from gestational day 16-22, to construct a DEX model. Rats were killed at 16weeks of age. Prenatal DEX induced sex-specific increase in BPs in male but not female adult offspring. Prenatal DEX elicited renal programming in a sex-specific fashion as demonstrated by 8 and 18 DEGs in male and female offspring, respectively. Among them, two genes, Hbb and Hba-a2, were shared. The resistance of female offspring to prenatal DEX-induced programmed hypertension is related to a lower Agt expression. Prenatal DEX induced programmed hypertension in adult male but not female offspring, which was related to renal programming affecting sex-biased genes and the RAS. Early identification of sex-specific underlying mechanisms could provide novel deprogramming strategy to reach maximal optimization in both sexes.

Early postnatal treatment with soluble epoxide hydrolase inhibitor or 15-deoxy-Δ(12,14)-prostagandin J2 prevents prenatal dexamethasone and postnatal high saturated fat diet induced programmed hypertension in adult rat offspring

Prenatal dexamethasone (DEX) exposure, postnatal high-fat (HF) intake, and arachidonic acid pathway are closely related to hypertension. We tested whether a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-deoxy-Δ(12,14)-prostagandin J2 (15dPGJ2) therapy can rescue programmed hypertension in the DEX+HF two-hit model. Four groups of Sprague Dawley rats were studied: control, DEX+HF, AUDA, and 15dPGJ2. Dexamethasone (0.1mg/kg body weight) was intraperitoneally administered to pregnant rats from gestational day 16-22. Male offspring received high-fat diet (D12331, Research Diets) from weaning to 4 months of age. In AUDA group, mother rats received 25mg/L in drinking water during lactation. In the 15dPGJ2 group, male offspring received 15dPGJ2 1.5mg/kg BW by subcutaneous injection once daily for 1 week after birth. We found postnatal HF diet aggravated prenatal DEX-induced programmed hypertension, which was similarly prevented by early treatment with AUDA or 15dPGJ2. The beneficial effects of AUDA and 15d-PGJ2 therapy include inhibition of SEH, increases of renal angiotensin converting enzyme-2 (ACE2) and angiotensin II type 2 receptor (AT2R) protein levels, and restoration of nitric oxide bioavailability. Better understanding of the impact of arachidonic acid pathway in the two-hit model will help prevent programmed hypertension in children exposed to corticosteroids and postnatal HF intake.

Postnatal dexamethasone-induced programmed hypertension is related to the regulation of melatonin and its receptors

Adulthood hypertension can be programmed by glucocorticoid exposure in early life. We found that maternal melatonin therapy prevents postnatal dexamethasone (DEX)-induced programmed hypertension. Melatonin acts through specific receptors, including MT1 and MT2 membrane receptors, and retinoid related orphan nuclear receptors of the RZR/ROR family. Thus we tested whether postnatal DEX-induced hypertension is related to changes of melatonin receptors in the kidney and heart, which was preserved by maternal melatonin therapy. Male neonates were assigned to four groups (n=6-8/group): control, DEX, control+melatonin (MEL), and DEX+MEL. Male rat pups were injected i.p. with DEX on d 1 (0.5 mg/kg BW), d 2 (0.3 mg/kg BW), and d 3 (0.1 mg/kg BW) after birth. Melatonin was administered in drinking water (0.01%) during the lactation period. We found DEX group developed hypertension at 16 weeks of age, which melatonin therapy prevented. Postnatal DEX treatment increased mRNA expression of MT1 and MT2, while decreased RORα and RZRβ in the kidney. These changes were prevented by melatonin therapy. Postnatal DEX decreased protein level of MT2 in the kidney, which was attenuated by melatonin therapy. Renal protein level of RORα was higher in DEX+MEL group compared to control and DEX group. Renal melatonin level was higher in the MEL and DEX+MEL groups compared to control. We concluded that melatonin therapy has long-term protection on postnatal DEX-induced programmed hypertension, which is associated with regulation on melatonin receptors in the kidney. Our findings would offer potential therapeutic approaches to prevent programmed hypertension in premature baby receiving glucocorticoids.

Postnatal High-Fat Diet Increases Liver Steatosis and Apoptosis Threatened by Prenatal Dexamethasone through the Oxidative Effect

The objective of this study was to investigate cellular apoptosis in prenatal glucocorticoid overexposure and a postnatal high fat diet in rats. Pregnant Sprague-Dawley rats at gestational days 14 to 21 were administered saline (vehicle) or dexamethasone and weaned onto either a normal fat diet or a high fat diet for 180 days; in total four experimental groups were designated, i.e., vehicle treated group (VEH), dexamethasone treated group (DEX), vehicle treated plus high-fat diet (VHF), and dexamethasone treated plus high-fat diet (DHF). Chronic effects of prenatal liver programming were assessed at postnatal day 180. The apoptotic pathways involved proteins were analyzed by Western blotting for their expressions. Apoptosis and liver steatosis were also examined by histology. We found that liver steatosis and apoptosis were increased in the DHF, DEX, and VHF treated groups, and that the DHF treated group was increased at higher levels than the DEX and VHF treated groups. The expression of leptin was decreased more in the DHF treated group than in the DEX and VHF treated groups. Decreased peroxisome proliferator-activated receptor-gamma coactivator 1α, phosphoinositide-3-kinase, manganese superoxide dismutase and increased malondialdehyde expression levels were seen in DHF treated group relative to the DEX treated group. The DHF treated group exhibited higher levels of oxidative stress, apoptosis and liver steatosis than the DEX treated group. These results indicate that the environment of high-fat diet plays an important role in the development of liver injury after prenatal stress.

PPARs Link Early Life Nutritional Insults to Later Programmed Hypertension and Metabolic Syndrome

Hypertension is an important component of metabolic syndrome. Adulthood hypertension and metabolic syndrome can be programmed in response to nutritional insults in early life. Peroxisome proliferator-activated receptors (PPARs) serve as a nutrient-sensing signaling linking nutritional programming to hypertension and metabolic syndrome. All three members of PPARs, PPARα, PPARβ/δ, and PPARγ, are expressed in the kidney and involved in blood pressure control. This review provides an overview of potential clinical applications of targeting on the PPARs in the kidney to prevent programmed hypertension and metabolic syndrome, with an emphasis on the following areas: mechanistic insights to interpret programmed hypertension; the link between the PPARs, nutritional insults, and programmed hypertension and metabolic syndrome; the impact of PPAR signaling pathway in a maternal high-fructose model; and current experimental studies on early intervention by PPAR modulators to prevent programmed hypertension and metabolic syndrome. Animal studies employing a reprogramming strategy via targeting PPARs to prevent hypertension have demonstrated interesting results. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies, to halt the globally-growing epidemic of metabolic syndrome-related diseases.