Antenatal glucocorticoid treatment alters Na+ uptake in renal proximal tubule cells from adult offspring in a sex-specific manner

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.

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.

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.

Fetal programming and the angiotensin-(1-7) axis: a review of the experimental and clinical data

Hypertension is the primary risk factor for cardiovascular disease that constitutes a serious worldwide health concern and a significant healthcare burden. As the majority of hypertension has an unknown etiology, considerable research efforts in both experimental models and human cohorts has focused on the premise that alterations in the fetal and perinatal environment are key factors in the development of hypertension in children and adults. The exact mechanisms of how fetal programming events increase the risk of hypertension and cardiovascular disease are not fully elaborated; however, the focus on alterations in the biochemical components and functional aspects of the renin-angiotensin (Ang) system (RAS) has predominated, particularly activation of the Ang-converting enzyme (ACE)-Ang II-Ang type 1 receptor (AT1R) axis. The emerging view of alternative pathways within the RAS that may functionally antagonize the Ang II axis raise the possibility that programming events also target the non-classical components of the RAS as an additional mechanism contributing to the development and progression of hypertension. In the current review, we evaluate the potential role of the ACE2-Ang-(1-7)-Mas receptor (MasR) axis of the RAS in fetal programming events and cardiovascular and renal dysfunction. Specifically, the review examines the impact of fetal programming on the Ang-(1-7) axis within the circulation, kidney, and brain such that the loss of Ang-(1-7) expression or tone, contributes to the chronic dysregulation of blood pressure (BP) and cardiometabolic disease in the offspring, as well as the influence of sex on potential programming of this pathway.

The detrimental effects of glucocorticoids exposure during pregnancy on offspring's cardiac functions mediated by hypermethylation of bone morphogenetic protein-4

The intra-uterine and external environmental factors not only affect the early development of fetuses, their interaction with genesis will also substantially program the physiological functions of offspring throughout life. Synthetic glucocorticoid (GC) is widely used for the management of women at risk of preterm birth or undergone autoimmune diseases. However, excess GC might cause a number of chronic diseases in later life. In the present study, we set up a programming rat model by daily injection of dexamethasone (DEX) since 14.5 dpc until labor, and found that the cardiac functions were significantly compromised in the male offspring compared with that exposed to NS, especially after ischemia/reperfusion (I/R), due to the increased infarction and apoptosis of myocardium. Using MeDIP sequencing, we identified four genes involved in the cardiac muscle cell differentiation and development pathway exhibited increased methylation in their promoter regions, among which, bone morphogenetic protein-4 (BMP4) expression is coordinately decreased in myocardium from male mice prenatally exposed to DEX. The programming effect of DEX on cardiomyocytes apoptosis was found to be dependent on mitochondria dysfunction, whereas the breakdown of mitochondrial membrane potential (ΔΨm) and the decrease of ATP production from mitochondria caused by prenatal DEX exposure both can be restored by BMP4 predisposing on neonatal cardiomyocytes 24 h prior to I/R. Inversely consistent with ΔΨm and ATP production, the release of reactive oxygen species was dramatically elevated in cardiomyocytes, which was significantly inhibited in the presence of BMP4 prior to I/R. These findings suggested that the excess GC exposure during pregnancy increases the susceptibility of male offspring’s heart to “second strike”, due to the decrease of BMP4 expression caused by the hypermethylation on Bmp4 promoter and the absence of BMP4 protective effect in cardiomyocytes, making the addition of BMP4 a promising treatment for the congenital heart disease under such circumstances.

Developmental Programming of Renal Function and Re-Programming Approaches

Chronic kidney disease affects more than 10% of the population. Programming studies have examined the interrelationship between environmental factors in early life and differences in morbidity and mortality between individuals. A number of important principles has been identified, namely permanent structural modifications of organs and cells, long-lasting adjustments of endocrine regulatory circuits, as well as altered gene transcription. Risk factors include intrauterine deficiencies by disturbed placental function or maternal malnutrition, prematurity, intrauterine and postnatal stress, intrauterine and postnatal overnutrition, as well as dietary dysbalances in postnatal life. This mini-review discusses critical developmental periods and long-term sequelae of renal programming in humans and presents studies examining the underlying mechanisms as well as interventional approaches to "re-program" renal susceptibility toward disease. Clinical manifestations of programmed kidney disease include arterial hypertension, proteinuria, aggravation of inflammatory glomerular disease, and loss of kidney function. Nephron number, regulation of the renin-angiotensin-aldosterone system, renal sodium transport, vasomotor and endothelial function, myogenic response, and tubuloglomerular feedback have been identified as being vulnerable to environmental factors. Oxidative stress levels, metabolic pathways, including insulin, leptin, steroids, and arachidonic acid, DNA methylation, and histone configuration may be significantly altered by adverse environmental conditions. Studies on re-programming interventions focused on dietary or anti-oxidative approaches so far. Further studies that broaden our understanding of renal programming mechanisms are needed to ultimately develop preventive strategies. Targeted re-programming interventions in animal models focusing on known mechanisms will contribute to new concepts which finally will have to be translated to human application. Early nutritional concepts with specific modifications in macro- or micronutrients are among the most promising approaches to improve future renal health.

Interplay between Oxidative Stress and Nutrient Sensing Signaling in the Developmental Origins of Cardiovascular Disease

Cardiovascular disease (CVD) presents a global health burden, despite recent advances in management. CVD can originate from early life by so-called “developmental origins of health and disease” (DOHaD). Epidemiological and experimental evidence supports that early-life insults can induce programming of later CVD. Underlying the DOHaD concept, early intervention may offset programming process to prevent the development of CVD, namely reprogramming. Oxidative stress and nutrient sensing signals have been considered to be major mechanisms of cardiovascular programming, while the interplay between these two mechanisms have not been examined in detail. This review summarizes current evidence that supports the link between oxidative stress and nutrient sensing signaling to cardiovascular programming, with an emphasis on the l-arginine–asymmetric dimethylarginine (ADMA)–nitric oxide (NO) pathway. This review provides an overview of evidence from human studies supporting fetal programming of CVD, insight from animal models of cardiovascular programming and oxidative stress, impact of the l-arginine–ADMA–NO pathway in cardiovascular programming, the crosstalk between l-arginine metabolism and nutrient sensing signals, and application of reprogramming interventions to prevent the programming of CVD. A greater understanding of the mechanisms underlying cardiovascular programming is essential to developing early reprogramming interventions to combat the globally growing epidemic of CVD.

Reproductive disorders in female rats after prenatal exposure to betamethasone

Betamethasone is the drug of choice for antenatal treatment, promoting fetal lung maturation and decreasing mortality. Previous studies in rats reported male programming and alteration in sperm parameters and sexual behavior following intrauterine betamethasone exposure. The impact on the female reproductive development is not known. In this study, rat female offspring was assessed for sexual development, morphophysiology of the reproductive tract and fertility after maternal exposure to 0.1 mg kg^-1 of betamethasone or vehicle on gestational days 12, 13, 18 and 19. The treatment promoted reduction of litter weight on postnatal day 1, morphological masculinization in females, delay in the age of puberty onset, reduction in estrus number, increase in estrous cycle length and increase in luteinizing hormone serum levels and uterus weight. The females from the betamethasone group showed an increase of myometrial uterine area and decrease in endometrial uterine area. These animals also performed less lordosis during the sexual behavior test and showed impaired reproductive performance. The uterus showed higher contraction in the treated group as shown by a pharmacological assay. In conclusion, prenatal betamethasone exposure in rats promoted female masculinization, altered sexual development and reproductive parameters. Copyright © 2017 John Wiley & Sons, Ltd.

Antenatal betamethasone attenuates the angiotensin-(1-7)-Mas receptor-nitric oxide axis in isolated proximal tubule cells

We previously reported a sex-specific effect of antenatal treatment with betamethasone (Beta) on sodium (Na⁺) excretion in adult sheep whereby treated males but not females had an attenuated natriuretic response to angiotensin-(1-7) [Ang-(1-7)]. The present study determined the Na⁺ uptake and nitric oxide (NO) response to low-dose Ang-(1-7) (1 pM) in renal proximal tubule cells (RPTC) from adult male and female sheep antenatally exposed to Beta or vehicle. Data were expressed as percentage of basal uptake or area under the curve for Na⁺ or percentage of control for NO. Male Beta RPTC exhibited greater Na⁺ uptake than male vehicle cells (433 ± 28 vs. 330 ± 26%; P < 0.05); however, Beta exposure had no effect on Na⁺ uptake in the female cells (255 ± 16 vs. 255 ± 14%; P > 0.05). Ang-(1-7) significantly inhibited Na⁺ uptake in RPTC from vehicle male (214 ± 11%) and from both vehicle (190 ± 14%) and Beta (209 ± 11%) females but failed to attenuate Na⁺ uptake in Beta male cells. Beta exposure also abolished stimulation of NO by Ang-(1-7) in male but not female RPTC. Both the Na⁺ and NO responses to Ang-(1-7) were blocked by Mas receptor antagonist d-Ala⁷-Ang-(1-7). We conclude that the tubular Ang-(1-7)-Mas-NO pathway is attenuated in males and not females by antenatal Beta exposure. Moreover, since primary cultures of RPTC retain both the sex and Beta-induced phenotype of the adult kidney in vivo they appear to be an appropriate cell model to examine the effects of fetal programming on Na⁺ handling by the renal tubules.

Antenatal steroid exposure and heart rate variability in adolescents born with very low birth weight

BACKGROUND

Reduced heart rate variability (HRV) suggests autonomic imbalance in the control of heart rate and is associated with unfavorable cardiometabolic outcomes. We examined whether antenatal corticosteroid (ANCS) exposure had long-term programming effects on HRV in adolescents born with very low birth weight (VLBW).

METHODS

Follow-up study of a cohort of VLBW 14-y olds born between 1992 and 1996 with 50% exposed to ANCS. HRV in both the time and frequency domains using Nevrokard Software was determined from a 5-min electrocardiogram tracing.

RESULTS

HRV data from 89 (35 male, 53 non-black) exposed (ANCS+) and 77 (28 male, 29 non-black) unexposed (ANCS-) adolescents were analyzed. HRV did not differ between ANCS+ and ANCS- black participants. However, in non-black participants, a significant interaction between ANCS and sex was observed, with ANCS- females having significantly greater HRV than ANCS+ females and males, and ANCS- males for both time and frequency domain variables.

CONCLUSION

Among non-black adolescents born with VLBW, ANCS exposure is associated with reduced HRV with apparent sex-specificity. Reduced HRV has been associated with development of adverse cardiometabolic outcomes, thus supporting the need to monitor these outcomes in VLBW adolescents as they mature.

Alterations in male rats following in utero exposure to betamethasone suggests changes in reproductive programming

Antenatal betamethasone is used for accelerating fetal lung maturation for women at risk of preterm birth. Altered sperm parameters were reported in adult rats after intrauterine exposure to betamethasone. In this study, male rat offspring were assessed for reproductive development after dam exposure to betamethasone (0.1mg/kg) or vehicle on Days 12, 13, 18 and 19 of pregnancy. The treatment resulted in reduction in the offspring body weight, delay in preputial separation, decreased seminal vesicle weight, testosterone levels and fertility, and increased testicular weight. In the testis, morphologically abnormal seminiferous tubules were observed, characterized by an irregular cell distribution with Sertoli cell that were displaced towards the tubular lumen. These cells expressed both Connexin 43 (Cx43) and Proliferative Nuclear Cell Antigen (PCNA). In conclusion, intrauterine betamethasone treatment appears to promote reproductive programming and impairment of rat sexual development and fertility due to, at least in part, unusual testicular disorders.

Perinatal programming of renal function

PURPOSE OF REVIEW

Perinatal programming of renal function reflects the epigenetic alteration of genetically determined development by environmental factors. These include intrauterine malnutrition, pre and postnatal overnutrition, glucocorticoids, and certain toxins such as smoking. This review aims to summarize the most important findings.

RECENT FINDINGS

Human studies may show an increased susceptibility toward the general prevalence of renal failure in already small for gestational age children and adolescents. In particular, glomerular diseases present with a more severe clinical course. Partially related, partially independently, arterial hypertension is found in this at-risk group. The findings can mostly be confirmed in animal models. Both intrauterine nutrient deprived and overfed rodents show a tendency toward developing glomerulosclerosis and other renal disorders. Animal studies attempt to imitate clinical conditions, however, there are difficulties in transferring the findings to the human setting. The reduction of nephron number, especially in intrauterine growth-restricted humans and animals, is one mechanism of perinatal programming in the kidneys. In addition, vascular and endocrine alterations are prevalent. The molecular changes behind these mechanisms include epigenetic changes such as DNA-methylation, microRNAs, and histone modifications.

SUMMARY

Future research will have to establish clinical studies with clear and well defined inclusion criteria which also reflect prenatal life. The use of transgenic animal models might help to obtain a deeper insight into the underlying mechanisms.

Increased maternal nighttime cortisol concentrations in late gestation alter glucose and insulin in the neonatal lamb

Previous studies in our laboratory have shown that a modest chronic increase in maternal cortisol concentrations impairs maternal glucose metabolism and increases the incidence of perinatal stillbirth. The dramatic outcomes prevented our ability to study the effects of maternal hypercortisolemia on neonatal growth, glucose metabolism, and hypothalamo–pituitary–adrenal axis response. Therefore, we developed a model in which pregnant ewes are infused for 12 h/day at 0.5 mg·kg^–1·day^–1 from day 115 of gestation until delivery (˜145), elevating nighttime plasma cortisol concentrations. This pattern of elevation of cortisol mimics that in patients with elevated evening cortisol concentrations, as in Cushing’s syndrome or chronic depression. Plasma cortisol, glucose, insulin, and electrolytes were measured during pregnancy and postpartum in control and cortisol-infused ewes and their postnatal lambs for the first 14 days after delivery. Neonatal growth and plasma ACTH, aldosterone, renin activity, and electrolytes, and organ weights at 14 days of age were also measured. Infusion of cortisol increased maternal plasma cortisol during pregnancy but not postpartum, and did not alter neonatal ACTH or cortisol. Although maternal glucose and insulin concentrations were not changed by the maternal infusion of cortisol, neonatal plasma glucose was increased and plasma insulin was decreased compared to those in the control group. Neonatal ponderal index and kidney weight were reduced, left ventricular wall thickness was increased, and plasma sodium and creatinine were increased after maternal cortisol infusion. These results suggest that excess maternal cortisol concentrations in late gestation alter growth, glucose and insulin regulation, and organ maturation in the neonate.