How the kidney is impacted by the perinatal maternal environment to develop hypertension

Corticosteroids alter kidney development and increase glomerular filtration rate in larval zebrafish (Danio rerio)

Pharmaceutical drugs and other chemicals can impact organogenesis, either during pregnancy or by postnatal exposure of very preterm infants. Corticosteroids are administered to pregnant women at risk of preterm delivery in order to reduce neonatal morbidity and mortality. In addition, high-dose corticosteroid exposure of very preterm infants regularly serves to maintain blood pressure and to prevent and treat bronchopulmonary dysplasia, a form of chronic lung disease in prematurely born infants. Despite clinical benefits, there is increasing evidence of corticosteroid-mediated short- and long-term detrimental developmental effects, especially in the kidney. Here, we performed a detailed morphological and functional analysis of corticosteroid-mediated effects on pronephros development in larval zebrafish. About 24-h postfertilization (hpf) transgenic Tg(wt1b: EGFP) zebrafish larvae were exposed to a set of natural and synthetic corticosteroids (hydrocortisone, dexamethasone, 6α-methylprednisolone, betamethasone, prednisolone, fludrocortisone, 11-deoxycorticosterone) with varying glucocorticoid and mineralocorticoid potency for 24 h at different concentrations. A semiautomated, multiparametric in vivo workflow enabled simultaneous assessment of kidney morphology, renal FITC-inulin clearance, and heart rate within the same larva. All corticosteroids exerted significant morphological and functional effects on pronephros development, including a significant hypertrophy of the pronephric glomeruli as well as dose-dependent increases in FITC-inulin clearance as a marker of glomerular filtration rate. In conclusion, the present study demonstrates a significant impact of corticosteroid exposure on kidney development and function in larval zebrafish. Hence, these studies underline that corticosteroid exposure of the fetus and the preterm neonate should be carefully considered due to potential short- and long-term harm to the kidney.

The role of preterm birth in stress-induced sodium excretion in young adults

BACKGROUND

Early-life programming due to prematurity and very low birth weight (VLBW, <1500 g) is believed to contribute to development of hypertension, but the mechanisms remain unclear. Experimental data suggest that altered pressure natriuresis (increased renal perfusion pressure promoting sodium excretion) may be a contributing mechanism. We hypothesize that young adults born preterm will have a blunted pressure natriuresis response to mental stress compared with those born term.

METHODS

In this prospective cohort study of 190 individuals aged 18-23 years, 156 born preterm with VLBW and 34 controls born term with birth weight at least 2500 g, we measured urine sodium/creatinine before and after a mental stress test and continuous blood pressure before and during the stress test. Participants were stratified into groups by the trajectory at which mean arterial pressure (MAP) increased following the test. The group with the lowest MAP trajectory was the reference group. We used generalized linear models to assess poststress urine sodium/creatinine relative to the change in MAP trajectory and assessed the difference between groups by preterm birth status.

RESULTS

Participants' mean age was 19.8 years and 57% were women. Change in urine sodium/creatinine per unit increase in MAP when comparing middle trajectory group against the reference group was greater in those born preterm [β 5.4%, 95% confidence interval (95% CI) -11.4 to 5.3] than those born term (β 38.5%, 95% CI -0.04 to 92.0), interaction term P = 0.002.

CONCLUSION

We observed that, as blood pressure increased following mental stress, young adults born preterm exhibited decreased sodium excretion relative to term-born individuals.

Perinatal Use of Citrulline Rescues Hypertension in Adult Male Offspring Born to Pregnant Uremic Rats

The growing recognition of the association between maternal chronic kidney disease (CKD) and fetal programming highlights the increased vulnerability of hypertension in offspring. Potential mechanisms involve oxidative stress, dysbiosis in gut microbiota, and activation of the renin-angiotensin system (RAS). Our prior investigation showed that the administration of adenine to pregnant rats resulted in the development of CKD, ultimately causing hypertension in their adult offspring. Citrulline, known for enhancing nitric oxide (NO) production and possessing antioxidant and antihypertensive properties, was explored for its potential to reverse high blood pressure (BP) in offspring born to CKD dams. Male rat offspring, both from normal and adenine-induced CKD models, were randomly assigned to four groups (8 animals each): (1) control, (2) CKD, (3) citrulline-treated control rats, and (4) citrulline-treated CKD rats. Citrulline supplementation successfully reversed elevated BP in male progeny born to uremic mothers. The protective effects of perinatal citrulline supplementation were linked to an enhanced NO pathway, decreased expression of renal (pro)renin receptor, and changes in gut microbiota composition. Citrulline supplementation led to a reduction in the abundance of Monoglobus and Streptococcus genera and an increase in Agothobacterium Butyriciproducens. Citrulline's ability to influence taxa associated with hypertension may be linked to its protective effects against maternal CKD-induced offspring hypertension. In conclusion, perinatal citrulline treatment increased NO availability and mitigated elevated BP in rat offspring from uremic mother rats.

Maternal protein deficiency alters primary cilia length in renal tubular and impairs kidney development in fetal rat

Introduction

Intrauterine malnutrition impairs embryo kidney development and leads to kidney disease and hypertension in adulthood, yet the underlying mechanism remains unclear.

Methods

With a maternal protein restriction (MPR) rat model, we investigated the critical ciliogenesis factors and β-catenin pathway in FGR fetal kidneys and analyzed the impact of aberrant primary cilia on renal tubular epithelium.

Results

The data showed decreased nephron number and renal tubular dysgenesis in FGR fetus. FGR fetus showed deregulated expression of ciliogenesis factors including upregulation of IFT88 and downregulation of DYNLT1, accompanied with cilia elongation in renal tubular epithelial cells. Wnt7b, the key ligand for Wnt/β-catenin signaling, was downregulated and nuclear translocation of β-catenin was decreased. The proapoptotic protein was upregulated. In vitro study with HK-2 cells showed that overexpression of IFT88 lengthened the cilia, inhibited β-catenin signaling. Besides, IFT88 overexpression suppressed cell proliferation, activated autophagy, and induced cell apoptosis. Inhibition of autophagy partly restored the cilia length and cell viability. Likewise, knockdown of DYNLT1 led to cilia elongation, suppressed cell proliferation, and promoted apoptosis in HK-2 cell. However, the cilia elongation induced by DYNLT1 knockdown was not autophagy-dependent, but associated with reactive oxygen species (ROS) accumulation.

Discussion

We elucidated that intrauterine protein malnutrition led to deregulation of ciliogenesis factors and cilia elongation in renal tubular epithelial, inhibited β-catenin signaling, and induced cell apoptosis and ultimately, compromised kidney development.

Continuous Monochromatic Blue Light Exacerbates High-Fat Diet-Induced Kidney Injury via Corticosterone-Mediated Oxidative Stress

Excessive illumination is one of the most severe environmental factors that impacts the organism. There is growing evidence that obesity significantly contributes to the onset of chronic kidney disease. However, the effect of continuous light on the kidney and which color can produce an apparent phenomenon remains elusive. In this study, C57BL/6 mice given either a normal diet (LD-WN) or a high-fat diet (LD-WF) were subjected to a light cycle of 12 h of illumination followed by 12 h of darkness for 12 weeks. Meanwhile, 48 high-fat diet mice were given a 24 h monochromatic light exposure of varying colors (white, LL-WF; blue, LL-BF; green, LL-GF) for 12 weeks. As expected, the LD-WF mice showed significant obesity, kidney injury, and renal dysfunction compared with the LD-WN group. LL-BF mice had worse kidney injury than LD-WF mice, including higher Kim-1 and Lcn2. The kidney of the LL-BF group showed marked glomerular and tubular injury, with decreased levels of Nephrin, Podocin, Cd2ap, and α-Actinin-4 compared to LD-WF. LL-BF also reduced the antioxidant capacity, including GSH-Px, CAT, and T-AOC, increased the production of MDA, and inhibited the activation of the NRF2/HO-1 signaling pathway. Furthermore, LL-BF upregulated the mRNA levels of the pro-inflammatory factors Tnf-α, Il-6, and Mcp-1, decreasing the inhibitory inflammatory Il-4 expression. We observed increased plasma corticosterone (CORT), renal glucocorticoid receptors (GR) expression, Hsp90, Hsp70, and P23 mRNA levels. These findings suggested that LL-BF increased CORT secretion and affected glucocorticoid receptors (GR) in comparison to the LD-WF group. Moreover, in vitro research demonstrated that CORT treatment increased oxidative stress and inflammation, which was counteracted by adding a GR inhibitor. Thus, the sustained blue light worsened kidney damage, possibly by inducing elevated CORT and increasing oxidative stress and inflammation via GR.

Maternal high-fat diet consumption during pregnancy and lactation predisposes offspring to renal and metabolic injury later in life: comparative study of diets with different lipid contents

Accumulating evidence suggests that maternal overnutrition can result in a higher development risk of obesity and renal disease in the offspring's adulthood. The present study tested different lipid levels in the maternal diet during pregnancy and lactation and its repercussions on the offspring of Wistar rats. Offspring of 1, 7, 30 and 90-d-old were divided into the following groups: Control (CNT) - offspring of dams that consumed a standard chow diet (3.5% of lipids); Experimental 1 (EXP1) - offspring of dams exposed to a high-fat diet (HFD) (28% of lipids); and Experimental 2 (EXP2) - offspring of dams exposed to a HFD (40% of lipids). Regarding maternal data, there was a decrease in the amount of diet ingested by EXP2. Daily caloric intake was higher in EXP1, while protein and carbohydrate intakes were lower in EXP2. While lipid intake was higher in the experimental groups, EXP1 consumed more lipids than EXP2, despite the body weight gain being higher in EXP2. Adult offspring from EXP1 presented higher blood glucose. Regarding morphometric analysis, in both experimental groups, there was an increase in the glomerular tuft and renal corpuscle areas, but an increase in the capsular space area only in EXP1. There was a decrease in the glomerular filtration rate (GFR) in EXP1, in contrast to an increase in GFR of EXP2, along with an increase in urinary protein excretion. In conclusion, the maternal HFDs caused significant kidney damage in offspring, but had different repercussions on the type and magnitude of recorded change.

The Role of the Paraventricular-Coerulear Network on the Programming of Hypertension by Prenatal Undernutrition

A crucial etiological component in fetal programming is early nutrition. Indeed, early undernutrition may cause a chronic increase in blood pressure and cardiovascular diseases, including stroke and heart failure. In this regard, current evidence has sustained several pathological mechanisms involving changes in central and peripheral targets. In the present review, we summarize the neuroendocrine and neuroplastic modifications that underlie maladaptive mechanisms related to chronic hypertension programming after early undernutrition. First, we analyzed the role of glucocorticoids on the mechanism of long-term programming of hypertension. Secondly, we discussed the pathological plastic changes at the paraventricular nucleus of the hypothalamus that contribute to the development of chronic hypertension in animal models of prenatal undernutrition, dissecting the neural network that reciprocally communicates this nucleus with the locus coeruleus. Finally, we propose an integrated and updated view of the main neuroendocrine and central circuital alterations that support the occurrence of chronic increases of blood pressure in prenatally undernourished animals.

Hypertension and renal disease programming: focus on the early postnatal period

The developmental origin of hypertension and renal disease is a concept highly supported by strong evidence coming from both human and animal studies. During development there are periods in which the organs are more vulnerable to stressors. Such periods of susceptibility are also called 'sensitive windows of exposure'. It was shown that as earlier an adverse event occurs; the greater are the consequences for health impairment. However, evidence show that the postnatal period is also quite important for hypertension and renal disease programming, especially in rodents because they complete nephrogenesis postnatally, and it is also important during preterm human birth. Considering that the developing kidney is vulnerable to early-life stressors, renal programming is a key element in the developmental programming of hypertension and renal disease. The purpose of this review is to highlight the great number of studies, most of them performed in animal models, showing the broad range of stressors involved in hypertension and renal disease programming, with a particular focus on the stressors that occur during the early postnatal period. These stressors mainly include undernutrition or specific nutritional deficits, chronic behavioral stress, exposure to environmental chemicals, and pharmacological treatments that affect some important factors involved in renal physiology. We also discuss the common molecular mechanisms that are activated by the mentioned stressors and that promote the appearance of these adult diseases, with a brief description on some reprogramming strategies, which is a relatively new and promising field to treat or to prevent these diseases.

Prenatal hypothyroidism diminished exogenous NO-mediated diastolic effects in fetal rat thoracic aorta smooth muscle via increased oxidative stress

Maternal hypothyroidism is an important problem of modern healthcare and is reported to increase the risk of cardiovascular diseases in the offspring later in life. However, it is unclear whether hypothyroidism during pregnancy causes vascular damage in the fetal period. We established the prenatal hypothyroidism rat model and collected the fetuses at the 21th day of gestation (GD21). Thyroid hormone concentrations in maternal and offspring blood serum were assessed by enzyme-linked immunosorbent assay (ELISA). The thoracic aortas of the fetuses were isolated for microvessel functional testing and histochemical stainings. qPCR and Western blot were performed to access mRNA and protein expression. We found that the concentrations of thyroid hormones in the serum of pregnant rats and fetuses were significantly suppressed at GD21. The responses of the fetal thoracic aortas to SNP were significantly attenuated in the PTU group. However, no statistical difference was found between the two groups when treated with either inhibitor (ODQ) or activator (BAY58-2667) of sGC. The production of O₂^-• in the arterial wall was significantly increased in hypothyroid fetuses. Moreover, the level of NADPH oxidase (NOX) was increased, while superoxide dismutase 2 (SOD2) was down-regulated in the PTU group, ultimately contributing to the increased production of superoxide. Additionally, decreased SNP-mediated vasodilation found in fetal vessels was improved by either NOX inhibitor (Apocynin) or SOD mimic (Tempol). These results indicate that increased oxidative stress is probably the cause of the diminished diastolic effect of exogenous NO in the thoracic artery of prenatal hypothyroidism exposed fetuses.

Novel intrauterine growth retardation model: effects of maternal subtotal nephrectomy on neonates

Changes in body weight (BW), systolic blood pressure (SBP), and localization of renin in the kidneys of neonates born to normal mothers (C neonates) or to five-sixths (5/6) nephrectomized (2/3 left kidney and right kidney) mothers (Nx neonates) were studied. Maternal 5/6 nephrectomy caused weight loss in neonates but no differences in SBP or renin localization. Culling Nx neonates to a litter of 3 at 1 day after birth resulted in growth catching up with C neonates from 3 weeks old and increases in both SBP and renin-positive cells in neonatal kidney. These findings revealed that maternal 5/6 nephrectomy results in low-birth-weight neonates and that these neonates are at increased risk of metabolic syndrome by catch-up growth.

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

This narrative review summarizes current evidence on the association between maternal low volume circulation and poor fetal growth. Though much work has been devoted to the study of cardiac output and peripheral vascular resistance, a low intravascular volume may explain why high vascular resistance causes hypertension in women with preeclampsia (PE) that is associated with fetal growth restriction (FGR) and, at the same time, presents with normotension in FGR itself. Normotensive women with small for gestational age babies show normal gestational blood volume expansion superimposed upon a constitutionally low intravascular volume. Early onset preeclampsia (EPE; occurring before 32 weeks) is commonly associated with FGR, and poor plasma volume expandability may already be present before conception, thus preceding gestational volume expansion. Experimentally induced low plasma volume in rodents predisposes to poor fetal growth and interventions that enhance plasma volume expansion in FGR have shown beneficial effects on intrauterine fetal condition, prolongation of gestation and birth weight. This review makes the case for elevating the maternal intravascular volume with physical exercise with or without Nitric Oxide Donors in FGR and EPE, and evaluating its role as a potential target for prevention and/or management of these conditions.

Novel Insights on Dietary Polyphenols for Prevention in Early-Life Origins of Hypertension: A Review Focusing on Preclinical Animal Models

Polyphenols are the largest group of phytochemicals with health benefits. Early life appears to offer a critical window of opportunity for launching interventions focused on preventing hypertension, as increasing evidence supports the supposition that hypertension can originate in early life. Although polyphenols have antihypertensive actions, knowledge of the potential beneficial action of the early use of polyphenols to avert the development of hypertension is limited. Thus, in this review, we first provide a brief summary of the chemistry and biological function of polyphenols. Then, we present the current epidemiological and experimental evidence supporting the early-life origins of hypertension. We also document animal data on the use of specific polyphenols as an early-life intervention to protect offspring against hypertension in adulthood and discuss underlying mechanisms. Continued research into the use of polyphenols to prevent hypertension from starting early in life will have far-reaching implications for future health.

Oxidative Stress-Induced Hypertension of Developmental Origins: Preventive Aspects of Antioxidant Therapy

Hypertension remains the leading cause of disease burden worldwide. Hypertension can originate in the early stages of life. A growing body of evidence suggests that oxidative stress, which is characterized as a reactive oxygen species (ROS)/nitric oxide (NO) disequilibrium, has a pivotal role in the hypertension of developmental origins. Results from animal studies support the idea that early-life oxidative stress causes developmental programming in prime blood pressure (BP)-controlled organs such as the brain, kidneys, heart, and blood vessels, leading to hypertension in adult offspring. Conversely, perinatal use of antioxidants can counteract oxidative stress and therefore lower BP. This review discusses the interaction between oxidative stress and developmental programming in hypertension. It will also discuss evidence from animal models, how oxidative stress connects with other core mechanisms, and the potential of antioxidant therapy as a novel preventive strategy to prevent the hypertension of developmental origins.

Adverse Impact of Environmental Chemicals on Developmental Origins of Kidney Disease and Hypertension

Chronic kidney disease (CKD) and hypertension are becoming a global health challenge, despite developments in pharmacotherapy. Both diseases can begin in early life by so-called "developmental origins of health and disease" (DOHaD). Environmental chemical exposure during pregnancy can affect kidney development, resulting in renal programming. Here, we focus on environmental chemicals that pregnant mothers are likely to be exposed, including dioxins, bisphenol A (BPA), phthalates, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAH), heavy metals, and air pollution. We summarize current human evidence and animal models that supports the link between prenatal exposure to environmental chemicals and developmental origins of kidney disease and hypertension, with an emphasis on common mechanisms. These include oxidative stress, renin-angiotensin system, reduced nephron numbers, and aryl hydrocarbon receptor signaling pathway. Urgent action is required to identify toxic chemicals in the environment, avoid harmful chemicals exposure during pregnancy and lactation, and continue to discover other potentially harmful chemicals. Innovation is also needed to identify kidney disease and hypertension in the earliest stage, as well as translating effective reprogramming interventions from animal studies into clinical practice. Toward DOHaD approach, prohibiting toxic chemical exposure and better understanding of underlying mechanisms, we have the potential to reduce global burden of kidney disease and hypertension.

Fructose plus High-Salt Diet in Early Life Results in Salt-Sensitive Cardiovascular Changes in Mature Male Sprague Dawley Rats

Fructose and salt intake remain high, particularly in adolescents and young adults. The present studies were designed to evaluate the impact of high fructose and/or salt during pre- and early adolescence on salt sensitivity, blood pressure, arterial compliance, and left ventricular (LV) function in maturity. Male 5-week-old Sprague Dawley rats were studied over three 3-week phases (Phases I, II, and III). Two reference groups received either 20% glucose + 0.4% NaCl (GCS-GCS) or 20% fructose + 4% NaCl (FHS-FHS) throughout this study. The two test groups ingested fructose + 0.4% NaCl (FCS) or FHS during Phase I, then GCS in Phase II, and were then challenged with 20% glucose + 4% NaCl (GHS) in Phase III: FCS-GHS and FHS-GHS, respectively. Compared with GCS-GCS, systolic and mean pressures were significantly higher at the end of Phase III in all groups fed fructose during Phase I. Aortic pulse wave velocity (PWV) was elevated at the end of Phase I in FHS-GHS and FHS-FHS (vs. GCS-GCS). At the end of Phase III, PWV and renal resistive index were higher in FHS-GHS and FHS-FHS vs. GCS-GCS. Diastolic, but not systolic, LV function was impaired in the FHS-GHS and FHS-FHS but not FCS-FHS rats. Consumption of 20% fructose by male rats during adolescence results in salt-sensitive hypertension in maturity. When ingested with a high-salt diet during this early plastic phase, dietary fructose also predisposes to vascular stiffening and LV diastolic dysfunction in later life.

Perinatal Resveratrol Therapy to Dioxin-Exposed Dams Prevents the Programming of Hypertension in Adult Rat Offspring

Exposure to environmental chemicals during pregnancy and lactation is a contributing factor in gut microbiota dysbiosis and linked to programming of hypertension. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic dioxin, induces toxic effects by mediating aryl hydrocarbon receptor (AHR). Resveratrol, a potent antioxidant with prebiotic properties, can possess high affinity for AHR and protect against TCDD-activated AHR attack. We examined whether perinatal resveratrol therapy prevents offspring hypertension programmed by maternal TCDD exposure and whether its beneficial effects are related to reshaping gut microbiota and antagonizing AHR-mediated T helper 17 (TH17) cells responses using a maternal TCDD exposure rat model. Pregnant Sprague-Dawley rats were given a weekly oral dose of TCDD 200 ng/kg for four doses (T), 50 mg/L of resveratrol in drinking water (CR), TCDD + resveratrol (TR), or vehicle (C) in pregnancy and lactation periods. Male offspring (n = 7–8/group) were sacrificed at the age of 12 weeks. Perinatal TCDD exposure caused elevated blood pressure in adult male offspring, which resveratrol supplementation prevented. Additionally, the TCDD-induced programming of hypertension is coincided with the activation of AHR signaling, TH17-induced renal inflammation, and alterations of gut microbiota compositions. Conversely, TCDD-mediated induction of AHR signaling and TH17 responses were restored by maternal resveratrol supplementation. Furthermore, maternal resveratrol supplementation prevented the programming of hypertension and was related to increased genera Bacteroides, ASF356, and Lachnoclostridium. Taken together, these results suggest that the interplay between gut microbiota, AHR-mediated TH17 responses, and renal inflammation in the gut and kidneys may play an important role in the action of resveratrol against TCDD-induced programming of hypertension.

Maternal 3,3-Dimethyl-1-Butanol Therapy Protects Adult Male Rat Offspring against Hypertension Programmed by Perinatal TCDD Exposure

Maternal exposure to environmental pollutants affects fetal development, which can result in hypertension in adulthood. Gut microbiota-derived metabolite trimethylamine (TMA), trimethylamine-N-oxide (TMAO), and short chain fatty acids (SCFAs) have been associated with hypertension. We tested a hypothesis that maternal 3,3-Dimethyl-1-butanol (DMB, a TMA inhibitor) therapy prevents 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure-induced hypertension in adult offspring relevant to alterations of gut microbiota-derived metabolites, the mediation of aryl hydrocarbon receptor (AHR) signaling, and the renin-angiotensin system (RAS). Pregnant Sprague-Dawley rats were given weekly oral dose of TCDD 200 ng/kg for four doses (T), 1% DMB in drinking water (D), TCDD + DMB (TD), or vehicle (C) in pregnancy and lactation periods. Male progeny (n = 8/group) were sacrificed at the age of 12 weeks. Perinatal TCDD exposure caused hypertension in adult male offspring coinciding with reduced α-diversity, increased the Firmicutes to Bacteroidetes ratio, less abundant beneficial bacteria, impaired SCFA receptors' expression, the activation of AHR signaling, and the aberrant activation of the RAS. Treatment with DMB during pregnancy and lactation rescued hypertension induced by perinatal TCDD exposure. This was accompanied by reshaping gut microbiota, mediating TMA-TMAO metabolic pathway, increasing acetic acid and its receptors, and restoring the AHR and RAS pathway. Our data provide new insights into the therapeutic potential of DMB, a microbiome-based metabolite treatment, for the prevention of hypertension of developmental origins.

Metabolic programming of nephron progenitor cell fate

Metabolic pathways are one of the first responses at the cellular level to maternal/fetal interface stressors. Studies have revealed the previously unrecognized contributions of intermediary metabolism to developmental programs. Here, we provide an overview of cellular metabolic pathways and the cues that modulate metabolic states. We discuss the developmental and physiological implications of metabolic reprogramming and the key role of metabolites in epigenetic and epiproteomic modifications during embryonic development and with respect to kidney development and nephrogenesis.

Gasotransmitters for the Therapeutic Prevention of Hypertension and Kidney Disease

Nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S), three major gasotransmitters, are involved in pleiotropic biofunctions. Research on their roles in hypertension and kidney disease has greatly expanded recently. The developing kidney can be programmed by various adverse in utero conditions by so-called renal programming, giving rise to hypertension and kidney disease in adulthood. Accordingly, early gasotransmitter-based interventions may have therapeutic potential to revoke programming processes, subsequently preventing hypertension and kidney disease of developmental origins. In this review, we describe the current knowledge of NO, CO, and H₂S implicated in pregnancy, including in physiological and pathophysiological processes, highlighting their key roles in hypertension and kidney disease. We summarize current evidence of gasotransmitter-based interventions for prevention of hypertension and kidney disease in animal models. Continued study is required to assess the interplay among the gasotransmitters NO, CO, and H₂S and renal programming, as well as a greater focus on further clinical translation.

Hypertension in Prenatally Undernourished Young-Adult Rats Is Maintained by Tonic Reciprocal Paraventricular-Coerulear Excitatory Interactions

Prenatally malnourished rats develop hypertension in adulthood, in part through increased α₁-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α₁-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α₁-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α₁-adrenoceptor density in whole hypothalamus and the expression levels of α_1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α₁-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α_1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular-coerulear excitatory interactions in prenatally undernourished young-adult rats.

Animal Models for DOHaD Research: Focus on Hypertension of Developmental Origins

Increasing evidence suggests that fetal programming through environmental exposure during a critical window of early life leads to long-term detrimental outcomes, by so-called developmental origins of health and disease (DOHaD). Hypertension can originate in early life. Animal models are essential for providing convincing evidence of a causal relationship between diverse early-life insults and the developmental programming of hypertension in later life. These insults include nutritional imbalances, maternal illnesses, exposure to environmental chemicals, and medication use. In addition to reviewing the various insults that contribute to hypertension of developmental origins, this review focuses on the benefits of animal models in addressing the underlying mechanisms by which early-life interventions can reprogram disease processes and prevent the development of hypertension. Our understanding of hypertension of developmental origins has been enhanced by each of these animal models, narrowing the knowledge gap between animal models and future clinical translation.

Altered Gut Microbiota and Its Metabolites in Hypertension of Developmental Origins: Exploring Differences between Fructose and Antibiotics Exposure

Gut microbiota-derived metabolites, in particular short chain fatty acids (SCFAs) and their receptors, are linked to hypertension. Fructose and antibiotics are commonly used worldwide, and they have a negative impact on the gut microbiota. Our previous study revealed that maternal high-fructose (HF) diet-induced hypertension in adult offspring is relevant to altered gut microbiome and its metabolites. We, therefore, intended to examine whether minocycline administration during pregnancy and lactation may further affect blood pressure (BP) programmed by maternal HF intake via mediating gut microbiota and SCFAs. Pregnant Sprague-Dawley rats received a normal diet or diet containing 60% fructose throughout pregnancy and lactation periods. Additionally, pregnant dams received minocycline (50 mg/kg/day) via oral gavage or a vehicle during pregnancy and lactation periods. Four groups of male offspring were studied (n = 8 per group): normal diet (ND), high-fructose diet (HF), normal diet + minocycline (NDM), and HF + minocycline (HFM). Male offspring were killed at 12 weeks of age. We observed that the HF diet and minocycline administration, both individually and together, causes the elevation of BP in adult male offspring, while there is no synergistic effect between them. Four groups displayed distinct enterotypes. Minocycline treatment leads to an increase in the F/B ratio, but decreased abundance of genera Lactobacillus, Ruminococcus, and Odoribacter. Additionally, minocycline treatment decreases plasma acetic acid and butyric acid levels. Hypertension programmed by maternal HF diet plus minocycline exposure is related to the increased expression of several SCFA receptors. Moreover, minocycline- and HF-induced hypertension, individually or together, is associated with the aberrant activation of the renin-angiotensin system (RAS). Conclusively, our results provide a new insight into the support of gut microbiota and its metabolite SCAFs in the developmental programming of hypertension and cast new light on the role of RAS in this process, which will help prevent hypertension programmed by maternal high-fructose and antibiotic exposure.

Targeting the Renin-Angiotensin-Aldosterone System to Prevent Hypertension and Kidney Disease of Developmental Origins

The renin-angiotensin-aldosterone system (RAAS) is implicated in hypertension and kidney disease. The developing kidney can be programmed by various early-life insults by so-called renal programming, resulting in hypertension and kidney disease in adulthood. This theory is known as developmental origins of health and disease (DOHaD). Conversely, early RAAS-based interventions could reverse program processes to prevent a disease from occurring by so-called reprogramming. In the current review, we mainly summarize (1) the current knowledge on the RAAS implicated in renal programming; (2) current evidence supporting the connections between the aberrant RAAS and other mechanisms behind renal programming, such as oxidative stress, nitric oxide deficiency, epigenetic regulation, and gut microbiota dysbiosis; and (3) an overview of how RAAS-based reprogramming interventions may prevent hypertension and kidney disease of developmental origins. To accelerate the transition of RAAS-based interventions for prevention of hypertension and kidney disease, an extended comprehension of the RAAS implicated in renal programming is needed, as well as a greater focus on further clinical translation.

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.

ADAM10 mediates ectopic proximal tubule development and renal fibrosis through Notch signalling

Disturbed intrauterine development increases the risk of renal disease. Various studies have reported that Notch signalling plays a significant role in kidney development and kidney diseases. A disintegrin and metalloproteinase domain 10 (ADAM10), an upstream protease of the Notch pathway, is also reportedly involved in renal fibrosis. However, how ADAM10 interacts with the Notch pathway and causes renal fibrosis is not fully understood. In this study, using a prenatal chlorpyrifos (CPF) exposure mouse model, we investigated the role of the ADAM10/Notch axis in kidney development and fibrosis. We found that prenatal CPF‐exposure mice presented overexpression of Adam10, Notch1 and Notch2, and led to premature depletion of Six2⁺ nephron progenitors and ectopic formation of proximal tubules (PTs) in the embryonic kidney. These abnormal phenotypic changes persisted in mature kidneys due to the continuous activation of ADAM10/Notch and showed aggravated renal fibrosis in adults. Finally, both ADAM10 and NOTCH2 expression were positively correlated with the degree of renal interstitial fibrosis in IgA nephropathy patients, and increased ADAM10 expression was negatively correlated with decreased kidney function evaluated by serum creatinine, cystatin C, and estimated glomerular filtration rate. Regression analysis also indicated that ADAM10 expression was an independent risk factor for fibrosis in IgAN. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Maternal exposure to high-fat and high-cholesterol diet induces arterial hypertension and oxidative stress along the gut-kidney axis in rat offspring

AIMS

Evaluate the effects of maternal high fat and high cholesterol (HFHC) diet consumption on blood pressure (BP), renal function and oxidative stress along the gut-kidney axis in male and female rat offspring.

MATERIALS AND METHODS

Pregnant rats were fed with a control (CTL) or HFHC diet during pregnancy and lactation. At 90 days, BP was assessed by tail-cuff plethysmography, and urinary and biochemical variables were measured. Biomarkers for oxidative stress, enzymatic antioxidant defense (activity of superoxide dismutase-SOD, catalase, and glutathione-S-transferase-GST) and nonenzymatic antioxidant defense (thiols content) were evaluated in the colon and renal cortex.

KEY FINDINGS

Male and female offspring from dams fed with a HFHC diet presented increased BP when compared to their respective CTL group. Male offspring from dams fed with HFHC diet showed reduced GST activity and thiols content in the colon, reduced SOD activity in the renal cortex and decreased urinary creatinine excretion when compared to the CTL group. Regarding female offspring, catalase activity and thiols content were reduced in the colon when compared to CTL group. Although lipid peroxidation had been increased in the renal cortex of HFHC female offspring, the CAT and SOD enzymatic antioxidant acitivities (CAT and SOD) were increased in the renal cortex of female offspring when compared with male offspring; and the renal function was not impaired by maternal HFHC diet consumption.

SIGNIFICANCE

HFHC diet during pregnancy and lactation induces sex-specific oxidative stress along the gut-kidney axis in offspring, which might induce renal dysfunction and arterial hypertension in later life.

Maternal exposure to cold spells during pregnancy is associated with higher blood pressure and hypertension in offspring later in life

We aimed to investigate whether month of birth is associated with blood pressure (BP) and prevalent hypertension in adults from a region with frost-free days of <150 days and average temperatures - 13°C in winter, Xinjiang, China. We analyzed data for 6158 subjects from several surveys. We divided participants into April to August (n = 2624) and September to March (n = 3534) groups, based on length of maternal exposure to cold months, and analyzed BP, prevalent hypertension, and related factors. Diastolic BP in total subjects and systolic and diastolic BP in male subjects born between April and August were significantly higher than in those born between September and March. In sensitivity analysis, untreated males born between April and August showed significantly higher systolic and diastolic BP than did their counterparts. Subjects born between April and August showed significantly higher prevalence of hypertension (31.3% vs 27.8%, P = .003), and isolated systolic (23.3% vs 20.8%, P = .018) and diastolic hypertension (24.5% vs 21.4%, P = .004), than those born between September and March, which is similar for men. Birth between April and August showed 1.68 (95% CI: 1.06-2.67, P = .027)-fold increased odds for the prevalence of hypertension, independent of gender, age, body mass index, waist circumference, cigarette consumption, alcohol intake, and family history, compared with their counterparts. In conclusion, maternal exposure to cold spells during pregnancy may be associated with the increased risk of hypertension in offspring later in life, particularly among males, suggesting the involvement of maternal cold exposure during pregnancy in offspring hypertension development.

Maternal high-fat diet increases vascular contractility in adult offspring in a sex-dependent manner

A maternal high-fat diet (HFD) is a risk factor for cardiovascular diseases in offspring. The aim of the study was to determine whether maternal HFD causes the epigenetic programming of vascular angiotensin II receptors (ATRs) and leads to heightened vascular contraction in adult male offspring in a sex-dependent manner. Pregnant rats were treated with HFD (60% kcal fat). Aortas were isolated from adult male and female offspring. Maternal HFD increased phenylephrine (PE)-and angiotensin II (Ang II)-induced contractions of the aorta in male but not female offspring. N^G-nitro-L-arginine (ʟ-NNA; 100 μM) abrogated the maternal HFD-induced increase in PE-mediated contraction. HFD caused a decrease in endothelium-dependent relaxations induced by acetylcholine in male but not female offspring. However, it had no effect on sodium nitroprusside-induced endothelium-independent relaxations of aortas regardless of sex. The AT₁ receptor (AT₁R) antagonist losartan (10 μM), but not the AT₂ receptor (AT₂R) antagonist PD123319 (10 μM), blocked Ang II-induced contractions in both control and HFD offspring in both sexes. Maternal HFD increased AT₁R but decreased AT₂R, leading to an increased ratio of AT₁R/AT₂R in HFD male offspring, which was associated with selective decreases in DNA methylation at the AT_1aR promoter and increases in DNA methylation at the AT₂R promoter. The vascular ratio of AT₁R/AT₂R was not significantly different in HFD female offspring compared with the control group. Our results indicated that maternal HFD caused a differential regulation of vascular AT₁R and AT₂R gene expression through a DNA methylation mechanism, which may be involved in HFD-induced vascular dysfunction and the development of a hypertensive phenotype in adulthood in a sex-dependent manner.

Early-Life Programming and Reprogramming of Adult Kidney Disease and Hypertension: The Interplay between Maternal Nutrition and Oxidative Stress

Kidney disease and hypertension both have attained the status of a global pandemic. Altered renal programming resulting in kidney disease and hypertension can begin in utero. Maternal suboptimal nutrition and oxidative stress have important implications in renal programming, while specific antioxidant nutrient supplementations may serve as reprogramming strategies to prevent kidney disease and hypertension of developmental origins. This review aims to summarize current knowledge on the interplay of maternal nutrition and oxidative stress in response to early-life insults and its impact on developmental programming of kidney disease and hypertension, covering two aspects. Firstly, we present the evidence from animal models supporting the implication of oxidative stress on adult kidney disease and hypertension programmed by suboptimal maternal nutrition. In the second part, we document data on specific antioxidant nutrients as reprogramming strategies to protect adult offspring against kidney disease and hypertension from developmental origins. Research into the prevention of kidney disease and hypertension that begin early in life will have profound implications for future health.

Selenoproteins and renal programming in metabolic syndrome-exposed rat offspring

Maternal metabolic syndrome (MS) during gestation and lactation leads to several cardiometabolic changes related to selenium (Se) status and selenoprotein expression in offspring. However, little is known about kidney programming and antioxidant selenoprotein status in MS pups. To gain more knowledge on this subject, two experimental groups of dam rats were used: Control (Se: 0.1 ppm) and MS (fructose 65% and Se: 0.1 ppm). At the end of lactation, Se deposits in kidneys, selenoprotein expression (GPx1, GPx3, GPx4 and selenoprotein P), oxidative balance and AMP-activated protein kinase (AMPK) and activated transcriptional factor NF-κB expression were measured. Kidney functional parameters, albuminuria, creatinine clearance, aldosteronemia, and water and electrolyte balance, were also evaluated. One week later systolic blood pressure was measured. Lipid peroxidation takes place in the kidneys of MS pups and Se, selenoproteins and NF-κB expression increased, while AMPK activation decreased. MS pups have albuminuria and low creatinine clearance which implies glomerular renal impairment with protein loss. They also present hypernatremia and hyperaldosteronemia, together with a high renal Na⁺ reabsorption, leading to a hypertensive status, which was detected in these animals one week later. Since these alterations seem to be related, at least in part, to oxidative stress, the increase in Se and selenoproteins found in the kidneys of these pups seems to be beneficial, avoiding a higher lipid oxidation. However, in order to analyze the possible global beneficial role of Se in kidneys during MS exposure, more data are necessary to document the relationships between GPx4 and NF-κB, and SelP and AMPK in kidneys.

Early Programming of Adult Systemic Essential Hypertension

Cardiovascular diseases are being included in the study of developmental origins of health and disease (DOHaD) and essential systemic hypertension has also been added to this field. Epigenetic modifications are one of the main mechanisms leading to early programming of disease. Different environmental factors occurring during critical windows in the early stages of life may leave epigenetic cues, which may be involved in the programming of hypertension when individuals reach adulthood. Such environmental factors include pre-term birth, low weight at birth, altered programming of different organs such as the blood vessels and the kidney, and living in disadvantageous conditions in the programming of hypertension. Mechanisms behind these factors that impact on the programming include undernutrition, oxidative stress, inflammation, emotional stress, and changes in the microbiota. These factors and their underlying causes acting at the vascular level will be discussed in this paper. We also explore the establishment of epigenetic cues that may lead to hypertension at the vascular level such as DNA methylation, histone modifications (methylation and acetylation), and the role of microRNAs in the endothelial cells and blood vessel smooth muscle which participate in hypertension. Since epigenetic changes are reversible, the knowledge of this type of markers could be useful in the field of prevention, diagnosis or epigenetic drugs as a therapeutic approach to hypertension.

Insights into sympathetic nervous system and GPCR interplay in fetal programming of hypertension: a bridge for new pharmacological strategies

Cardiovascular diseases (CVDs) are the most common cause of death from noncommunicable diseases worldwide. In addition to the classical CVD risk factors related to lifestyle and/or genetic background, exposure to an adverse intrauterine environment compromises fetal development leading to low birth weight and increasing offspring susceptibility to develop CVDs later in life, particularly hypertension - a process known as fetal programming of hypertension (FPH). In FPH animal models, permanent alterations have been detected in gene expression, in the structure and function of heart and blood vessels, compromising cardiovascular physiology and favoring hypertension development. This review focuses on the role of the sympathetic nervous system and its interplay with G-protein-coupled receptors, emphasizing strategies that envisage the prevention and/or treatment of FPH through interventions in early life.

Omega-3 attenuates high fat diet-induced kidney injury of female rats and renal programming of their offsprings

Context: Maternal diet composition could influence fetal organogenesis. Objective: We investigated effects of high fat diet (HFD) intake alone or combined with omega 3 during pregnancy, lactation and early days of weaning on nephrogenesis of pups and maternal renal function and morphology. Material and methods: Mothers and their pups included in each group were supplied with the same diet composition. Rats were divided into group I, II and III supplied with chow of either 10 kcal%, 45 kcal% or 45 kcal% from fat together with omega-3 respectively. Results: Group II showed increased serum urea and creatinine, renal TNF-α, IL1β. Structural injury was observed in mothers and their pups as Bowman's capsule and tubular dilatation and increased expression of PCNA that were decreased following omega-3 supplementation added to down regulation of Wnt4, Pax2 gene and podocin expression. Discussion and conclusion: Omega-3 supplementation improves lipid nephrotoxicity observed in mothers and their pups.

Targeting on Gut Microbial Metabolite Trimethylamine-N-Oxide and Short-Chain Fatty Acid to Prevent Maternal High-Fructose-Diet-Induced Developmental Programming of Hypertension in Adult Male Offspring

SCOPE

Alterations of gut metabolites, such as SCFAs and trimethylamine (TMA), and microbial composition are associated with the development of hypertension. Whether maternal 3,3-dimethyl-1-butanol (DMB, an inhibitor for TMA formation) treatment or the predominant SCFA acetate supplementation can prevent programed hypertension induced by a high-fructose diet (HFD) exposure during pregnancy and lactation in adult male offspring is examined.

METHODS AND RESULTS

Male offspring are divided into four groups: ND, normal diet; HFD, 60% HFD; ACE, HFD plus 200 mmol L^-1 magnesium acetate in drinking water; and DMB: HFD plus 1% DMB in drinking water. Maternal HFD induces programed hypertension in adult male offspring, which is prevented by maternal acetate supplementation or DMB treatment. HFD-induced hypertension is relevant to increased plasma levels of TMA and acetate, and alterations of gut microbial composition. The protective effects of acetate supplementation are associated with decreased plasma TMA level and TMA-to-trimethylamine-N-oxide (TMAO) ratio, and increased renal expression of SCFA receptors. Maternal DMB treatment reduces plasma TMA, TMAO, acetate, and propionate levels.

CONCLUSION

Early intervention targeting on gut-microbiota-derived metabolites TMAO and SCFAs to reprogram hypertension may have significant impact to reduce the burden of hypertension.

Maternal Metformin Treatment Improves Developmental and Metabolic Traits of IUGR Fetuses

Metformin is an anti-hyperglycemic drug widely used for the treatment of insulin resistance and glucose intolerance and is currently considered for preventing large-for-gestational-age (LGA) offspring in pregnant women affected by obesity or diabetes. Our hypothesis was the opposite—metformin may be used for improving the development of offspring affected by intrauterine growth restriction (IUGR) and preventing the appearance of small-for-gestational-age (SGA) neonates in non-obese and non-diabetic but malnourished pregnancies. The current study, performed in a swine preclinical model of IUGR by undernutrition, showed that fetuses in the treated group showed no significant increases in body-weight, but showed a significantly higher weight of the brain, the total thoracic and abdominal viscera, the liver, the kidneys, the spleen, and the adrenal glands. Maternal metformin treatment was also related to significant increases in the fetal plasma concentration of parameters indicative of glycemic (glucose and fructosamine) and lipid profiles (triglycerides). Overall, these results suggest a protective effect of the treatment on the developmental competence of the fetuses. These findings may be of high value for human medicine in case of maternal malnutrition, since metformin is a cheap drug easily available, but also in case of placental deficiency, since metformin seems to improve placental development and function.

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.

Regulation of Nitric Oxide Production in the Developmental Programming of Hypertension and Kidney Disease

Development of the kidney can be altered in response to adverse environments leading to renal programming and increased vulnerability to the development of hypertension and kidney disease in adulthood. By contrast, reprogramming is a strategy shifting therapeutic intervention from adulthood to early life to reverse the programming processes. Nitric oxide (NO) is a key mediator of renal physiology and blood pressure regulation. NO deficiency is a common mechanism underlying renal programming, while early-life NO-targeting interventions may serve as reprogramming strategies to prevent the development of hypertension and kidney disease. This review will first summarize the regulation of NO in the kidney. We also address human and animal data supporting the link between NO system and developmental programming of hypertension and kidney disease. This will be followed by the links between NO deficiency and the common mechanisms of renal programming, including the oxidative stress, renin–angiotensin system, nutrient-sensing signals, and sex differences. Recent data from animal studies have suggested that interventions targeting the NO pathway could be reprogramming strategies to prevent the development of hypertension and kidney disease. Further clinical studies are required to bridge the gap between animal models and clinical trials in order to develop ideal NO-targeting reprogramming strategies and to be able to have a lifelong impact, with profound savings in the global burden of hypertension and kidney disease.

Effectiveness of citrulline and N-carbamoyl glutamate as arginine precursors on reproductive performance in mammals: A systematic review

The use of functional nutrients has been proposed to reduce the occurrence of intrauterine growth retardation in animals at birth in several mammalian species. The objective of this study was to verify the effectiveness of citrulline and N-carbamylglutamate (NCG) dietary supplementation as arginine precursors for mammalian species, and the effects on fetal development through a systematic review. The search for studies was performed during August 2018 in the PubMed, ISI Web of Science, Science Direct, and Scopus databases. The literature search was conducted using "arginine precursor", "citrulline", or "N-carbamylglutamate" as keywords, combined with "gestation", "pregnancy", "fetus", "newborn", or "reproduction". Studies in which arginine precursors were evaluated in gestating mammals and their effects on parameters related to the intrauterine development of the conceptus were selected. Of 1,379 articles, 18 were selected, primarily based on the title and the abstract. Supplementation with NCG (0.5 g to 2 g/kg of feed) increased maternal plasma arginine concentrations in all studies that evaluated this variable. Fetal number increased in 55.56% of the studies that evaluated it, and fetal weight increased in the majority (62.5%) of the studies evaluating this variable. By supplementing citrulline, only fetal weight was improved, with an increase in maternal plasma arginine in 40% of the studies. In conclusion, N-carbamoyl glutamate seems to be an arginine precursor more effective than L-citrulline during gestation; however, both precursors, beside L-Arginine, should be evaluated in similar conditions to confirm the existence of specific particularities such as periods and levels of supplementation, which need to be considered for different species of animals. The supplementation of NCG increases arginine concentrations in maternal plasma, thus improving mammalian reproductive efficiency and fetal development, mainly by promoting higher birth weight.

Maternal Resveratrol Therapy Protects Male Rat Offspring against Programmed Hypertension Induced by TCDD and Dexamethasone Exposures: Is It Relevant to Aryl Hydrocarbon Receptor?

Hypertension can originate from early-life adverse environmental in utero exposure to dexamethasone (DEX) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Since DEX and TCDD are related to the aryl hydrocarbon receptor (AHR) signaling pathway, we examined whether resveratrol, an AHR modulator and antioxidant, could prevent programmed hypertension via regulating AHR signaling and oxidative stress. Groups of four-month-old male rat offspring were studied (n = 7⁻8 per group): control, DEX (0.1 mg/kg i.p. from a gestational age of 16 to 22 days), TCDD (200 ng/kg in four once-weekly oral doses), DEX + TCDD, and DEX + TCDD + R (resveratrol 0.05% in drinking water throughout pregnancy and lactation). Maternal TCDD exposure aggravated prenatal DEX-induced hypertension in adult male offspring, which maternal resveratrol therapy prevented. Maternal TCDD exposure aggravated DEX-induced oxidative damage in offspring kidneys, which was prevented by resveratrol therapy. Maternal resveratrol therapy decreased asymmetric and symmetric dimethylarginine (ADMA and SDMA) levels, thereby preventing combined DEX and TCDD exposure-induced programmed hypertension. Increases in renal Ahrr and Cyp1a1 expression induced by DEX + TCDD exposure were restored by resveratrol therapy. The beneficial effects of resveratrol on DEX + TCDD-induced hypertension relate to reduced renal mRNA expression of Ren, Ace, and Agtr1a expression. Thus, the beneficial effects of resveratrol on DEX + TCDD-induced hypertension include reduction of oxidative stress, restoration of nitric oxide (NO) bioavailability, blockade of the renin⁻angiotensin system (RAS), and antagonizing AHR signaling pathway.

Implication of Oxidative Stress in Fetal Programming of Cardiovascular Disease

Lifestyle and genetic background are well known risk factors of cardiovascular disease (CVD). A third contributing factor is suboptimal fetal development, due to nutrient or oxygen deprivation, placental insufficiency, or exposure to toxic substances. The fetus adapts to adverse intrauterine conditions to ensure survival; the immediate consequence is low birth weight (LBW) and the long-term effect is an increased susceptibility to develop CVD in adult life. This process is known as Developmental Origins of Health and Disease (DOHaD) or fetal programming of CVD. The influence of fetal life for the future cardiovascular health of the individual has been evidenced by numerous epidemiologic studies in populations suffering from starvation during intrauterine life. Furthermore, experimental animal models have provided support and enabled exploring the underlying mechanisms. Oxidative stress seems to play a central role in fetal programming of CVD, both in the response of the feto-placental unit to the suboptimal intrauterine environment and in the alterations of physiologic systems of cardiovascular control, ultimately leading to disease. This review aims to summarize current knowledge on the alterations in oxidative balance in response to fetal stress factors covering two aspects. Firstly, the evidence from human studies of the implication of oxidative stress in LBW induced by suboptimal conditions during intrauterine life, emphasizing the role of the placenta. In the second part we summarize data on specific redox alterations in key cardiovascular control organs induced by exposure to known stress factors in experimental animals and discuss the emerging role of the mitochondria.

Hydrogen Sulfide in Hypertension and Kidney Disease of Developmental Origins

Adverse environments occurring during kidney development may produce long-term programming effects, namely renal programming, to create increased vulnerability to the development of later-life hypertension and kidney disease. Conversely, reprogramming is a strategy aimed at reversing the programming processes in early life, even before the onset of clinical symptoms, which may counter the rising epidemic of hypertension and kidney disease. Hydrogen sulfide (H₂S), the third gasotransmitter, plays a key role in blood pressure regulation and renal physiology. This review will first present the role of H₂S in the renal system and provide evidence for the links between H₂S signaling and the underlying mechanisms of renal programming, including the renin–angiotensin system, oxidative stress, nutrient-sensing signals, sodium transporters, and epigenetic regulation. This will be followed by potential H₂S treatment modalities that may serve as reprogramming strategies to prevent hypertension and kidney disease of developmental origins. These H₂S treatment modalities include precursors for H₂S synthesis, H₂S donors, and natural plant-derived compounds. Despite emerging evidence from experimental studies in support of reprogramming strategies targeting the H₂S signaling pathway to protect against hypertension and kidney disease of developmental origins, these results need further clinical translation.

Up-regulation of renal renin-angiotensin system and inflammatory mechanisms in the prenatal programming by low-protein diet: beneficial effect of the post-weaning losartan treatment

Previous studies have shown that the renin-angiotensin system (RAS) is affected by adverse maternal nutrition during pregnancy. The aim of this study was to investigate the effects of a maternal low-protein diet on proinflammatory cytokines, reactive oxygen species and RAS components in kidney samples isolated from adult male offspring. We hypothesized that post-weaning losartan treatment would have beneficial effects on RAS activity and inflammatory and oxidative stress markers in these animals. Pregnant Sprague-Dawley rats were fed with a control (20% casein) or low-protein diet (LP) (6% casein) throughout gestation. After weaning, the LP pups were randomly assigned to LP and LP-losartan groups (AT1 receptor blockade: 10 mg/kg/day until 20 weeks of age). At 20 weeks of age, blood pressure levels were higher and renal RAS was activated in the LP group. We also observed several adverse effects in the kidneys of the LP group, including a higher number of CD3, CD68 and proliferating cell nuclear antigen-positive cells and higher levels of collagen and reactive oxygen species in the kidney. Further, our results revealed that post-weaning losartan treatment completely abolished immune cell infiltration and intrarenal RAS activation in the kidneys of LP rats. The prevention of augmentation of angiotensin (Ang II) concentration abolished inflammatory and fibrotic events, indicating that Ang II via the AT1 receptor is essential for pathological initiation. Our results suggest that the prenatal programming of hypertension is dependent on the up-regulation of local RAS and presence of immune cells in the kidney.

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.

Effects of low-dose melamine exposure during pregnancy on maternal and fetal kidneys in rats

Despite the previous reports on melamine contamination in high concentrations some years ago, there were not many studies on low-level exposure in daily life, particularly in pregnancy. We investigated the effect of low-dose melamine on the kidneys of the pregnant rats and their developing embryos/fetuses during various gestational stages namely implantation, gastrulation, organogenesis, maturation and whole pregnancy. Our results showed that the repeated low level of melamine (12.5, 25, and 50 mg/kg bw/d) during pregnancy did not cause obstruction of renal tubules although more precipitating crystals were found in the early gestational periods. Simple hyperplasia in the maternal tubules and pelvic epithelium were more prominent after exposed to melamine during the whole gestational period. Neonatal kidneys significantly suffered more from congestion in glomeruli and interstitium, dilated tubules and interstitial edema after melamine administration to the mother in the late and the whole gestational periods. A trend of advance of glomerular development in fetuses was also observed. We conclude that in utero exposure of low-level melamine could post a risk on the kidneys of the pregnant mother as well as the developing fetuses, which may further increase the possibility of other health problems later in life.

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.

The Epigenetic Machinery in Vascular Dysfunction and Hypertension

Hypertension (HT) is among the major components of the metabolic syndrome, i.e., obesity, dyslipidemia, and hyperglycemia/insulin resistance. It represents a significant health problem with foremost risks for chronic cardiovascular disease and a significant cause of morbidity and mortality worldwide. Therefore, it is not surprising that this disorder constitutes a serious public health concern. Although multiple studies have stressed the multifactorial nature of HT, the pathogenesis remains largely unknown. However, if we want to reduce the global prevalence of HT, restrain the number of deaths (currently 9.4 million/year in the world), and alleviate the socio-economic burden, a deeper insight into the mechanisms is urgently needed in order to define new meaningful therapeutic targets. Recently, the role of epigenetics in the development of various complex diseases has attracted much attention. In the present review, we provide a critical update on the available literature and ongoing research regarding the epigenetic modifications of genes involved in several pathways of elevated blood pressure, especially those linked to the vascular epithelium. This review also focuses on the role of microRNA (miRNA) in the regulation of gene expression associated with HT and of fetal programming mediating susceptibility to HT in adulthood.