Developmental programming of cardiovascular disorders: focus on hypertension

Birth Weight and Maternal Body Size as Determinants of Blood Pressure at Age 17: Results from the Jerusalem Perinatal Study Cohort

OBJECTIVES

To investigate the effect of birth weight (BW) and maternal pre-pregnancy BMI (mBMI) on blood pressure (BP) in adolescence.

METHODS

A Population-based cohort of 11,729 births in Jerusalem during 1974-1976, with archival data on maternal and birth characteristics was performed. Measurements at age 17 were assessed and linear regression models were used to evaluate the associations of birth characteristics with BP outcomes.

RESULTS

BW was inversely associated with both systolic (SBP) and diastolic (DBP) BP at age 17 (SBP: B = - 0.829, p = 0.002; DBP: B = - 0.397, p = 0.033). The interaction term between BW and weight at age 17 was significant for DBP (p = 0.017) and pulse pressure (p = 0.005). mBMI yielded significant positive associations with BP, independent of BW.

CONCLUSIONS FOR PRACTICE

Our findings indicate that there are at least two distinct pathways linking early life characteristics with subsequent BP: Intrauterine growth, as reflected by BW and other genetic or environmental factors, reflected by mBMI and maternal education, contribute to offspring adolescent BP. These results warrant replication in other birth cohorts and underline the need to explore specific mechanisms that account for these associations.

Prenatal Alcohol Exposure and the Associated Risk of Elevated Blood Pressure: A Cross-sectional Analysis of 3- to 17-Year-Olds in Germany

BACKGROUND

As the prevalence of obesity and high blood pressure increases among the population, early action is needed to reduce blood pressure. Certain lifestyles during pregnancy have negative effects resulting in high blood pressure for children and adolescents. Using data from the "German Health Interview and Examination Survey for Children and Adolescents" (KiGGS), this study analyzed: (i) the association between low-to-moderate prenatal alcohol exposure (PAE) and the risk of increased systolic and diastolic blood pressure and (ii) whether associations were modified by socioeconomic status (SES), prenatal smoke exposure (PSE), and body mass index (BMI) of the children and adolescents.

METHODS

We applied multivariate logistic regression analyses and stratified analyses by SES, PSE, and BMI with cross-sectional data from the KiGGS study (N = 14,253) to examine the association between PAE and prehypertension or hypertension in 3- to 17-year-olds.

RESULTS

Of the surveyed children and adolescents, 13.7% had a systolic prehypertension and 11.5% had a diastolic prehypertension. A further 7.5% were identified as having systolic hypertension and 6.0% diastolic hypertension. In the regression analyses, PAE resulted in a decreased risk of systolic prehypertension (odds ratio [OR]: 0.83, 95% confidence interval [CI]: 0.70, 0.99) and diastolic prehypertension (OR: 0.82, 95% CI: 0.68, 0.98). Risk reductions were not significant in surveyed children and adolescents with hypertension. Interactions between PAE and SES, PSE, and offspring BMI were not significant.

CONCLUSIONS

Contrary to our initial hypothesis, PAE reduces the risk of prehypertension. Animal studies suggest that vasodilation is induced by nitric oxide in small quantities of PAE.

Stimulation of the ACE2/Ang-(1-7)/Mas axis in hypertensive pregnant rats attenuates cardiovascular dysfunction in adult male offspring

The aim of this study was to investigate whether treatment with diminazene aceturate (DIZE), a putative ACE2 activator, or with angiotensin-(1-7) during pregnancy could attenuate the development of cardiovascular dysfunction in the adult offspring of spontaneously hypertensive rats (SHRs). For this, pregnant SHRs received DIZE or Ang-(1-7) throughout gestation. The systolic blood pressure (SBP) was measured in the male offspring from the 6th to16th weeks of age by tail-cuff plethysmography. Thereafter, the left ventricular contractile function and coronary reactivity were evaluated by the Langendorff technique. Samples of the left ventricles (LVs) and kidneys were collected for histology and western blot assay in another batch of adult rat offspring. Maternal treatment with DIZE or Ang-(1-7) during pregnancy attenuated the increase in SBP in adult offspring. In addition, both DIZE and Ang-(1-7) treatments reduced the cardiomyocyte diameter and fibrosis deposition in the LV, and treatment with Ang-(1-7) also reduced the fibrosis deposition in the kidneys. Maternal treatment with DIZE, as well as Ang-(1-7), improved the coronary vasodilation induced by bradykinin in isolated hearts from adult offspring. However, no difference was observed in the contractile function of the LVs of these animals. The expression levels of AT1 and Mas receptors, ACE, ACE2, SOD, and catalase in the LV were not modified by maternal treatment with Ang-(1-7), but this treatment elicited a reduction in AT2 expression. These data show that treatment with DIZE or Ang-(1-7) during gestation promoted beneficial effects of attenuating hypertension and cardiac remodeling in adult offspring.

Reprogramming: A Preventive Strategy in Hypertension Focusing on the Kidney

Adulthood hypertension can be programmed in response to a suboptimal environment in early life. However, developmental plasticity also implies that one can prevent hypertension in adult life by administrating appropriate compounds during early development. We have termed this reprogramming. While the risk of hypertension has been assessed in many mother-child cohorts of human developmental programming, interventions necessary to prove causation and provide a reprogramming strategy are lacking. Since the developing kidney is particularly vulnerable to environmental insults and blood pressure is determined by kidney function, renal programming is considered key in developmental programming of hypertension. Common pathways, whereby both genetic and acquired developmental programming converge into the same phenotype, have been recognized. For instance, the same reprogramming interventions aimed at shifting nitric oxide (NO)-reactive oxygen species (ROS) balance, such as perinatal citrulline or melatonin supplements, can be protective in both genetic and developmentally programmed hypertension. Furthermore, a significantly increased expression of gene Ephx2 (soluble epoxide hydrolase) was noted in both genetic and acquired animal models of hypertension. Since a suboptimal environment is often multifactorial, such common reprogramming pathways are a practical finding for translation to the clinic. This review provides an overview of potential clinical applications of reprogramming strategies to prevent programmed hypertension. We emphasize the kidney in the following areas: mechanistic insights from human studies and animal models to interpret programmed hypertension; identified risk factors of human programmed hypertension from mother-child cohorts; and the impact of reprogramming strategies on programmed hypertension from animal models. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies.

Prenatal dexamethasone-induced programmed hypertension and renal programming

AIMS

Antenatal glucocorticoids can induce long-term effects on offspring health, including hypertension. Programmed hypertension has been observed in a prenatal dexamethasone (DEX) exposure model. However, how renal programming responds to prenatal DEX at different stages of development and the impact of DEX on programmed hypertension remain unclear. Therefore, we utilized RNA next-generation sequencing (NGS) to analyze the renal transcriptome in the offspring to examine whether key genes and pathways are responsible for DEX-induced renal programming and hypertension.

MAIN METHODS

Pregnant rats received intraperitoneal dexamethasone from gestational day 16 to 22. Prenatal DEX-induced programmed hypertension was examined in male offspring at 16 weeks of age.

KEY FINDINGS

Prenatal DEX modified 431 renal transcripts from the nephrogenesis stage to adulthood in a constant manner. At the pre-hypertensive and established hypertension stages, we identified 11 and 13 differentially expressed genes related to blood pressure regulation, respectively. Among these genes, Npr3, Ptgs2, Agt, Edn3, Ephx2, Agtr1b, and Gucy1a3 are associated with endothelium-derived hyperpolarizing and contractile factors (EDHF and EDCF). Genes in the arachidonic acid metabolism pathway may potentially be key genes contributing to programmed hypertension. In addition, DEX induced soluble epoxide hydrolase expression (Ephx2 gene encoding protein).

SIGNIFICANCE

Prenatal DEX elicits an imbalance between EDHFs and EDCFs that might lead to renal programming and hypertension. The arachidonic acid metabolism pathway is a common pathway contributing to programmed hypertension. Our results highlight candidate genes and pathways involved in renal programming as targets for therapeutic approaches to prevent programmed hypertension in children exposed to antenatal corticosteroids.

Effect of a high-fat--high-fructose diet, stress and cinnamon on central expression of genes related to immune system, hypothalamic-pituitary-adrenocortical axis function and cerebral plasticity in rats

The intake of a high-fat/high-fructose (HF/HFr) diet is described to be deleterious to cognitive performances, possibly via the induction of inflammatory factors. An excess of glucocorticoids is also known to exert negative effects on cerebral plasticity. In the present study, we assessed the effects of an unbalanced diet on circulating and central markers of inflammation and glucocorticoid activity, as well as their reversal by dietary cinnamon (CN) supplementation. A group of male Wistar rats were subjected to an immune challenge with acute lipopolysaccharide under a HF/HFr or a standard diet. Another group of Wistar rats were fed either a HF/HFr or a control diet for 12 weeks, with or without CN supplementation, and with or without restraint stress (Str) application before being killed. We evaluated the effects of such regimens on inflammation parameters in the periphery and brain and on the expression of actors of brain plasticity. To assess hypothalamic-pituitary-adrenocortical axis activity, we measured the plasma concentrations of corticosterone and the expression of central corticotrophin-releasing hormone, mineralocorticoid receptor, glucocorticoid receptor and 11β-hydroxysteroid dehydrogenase. We found that the HF/HFr diet induced the expression of cytokines in the brain, but only after an immune challenge. Furthermore, we observed the negative effects of Str on the plasma concentrations of corticosterone and neuroplasticity markers in rats fed the control diet but not in those fed the HF/HFr diet. Additionally, we found that CN supplementation exerted beneficial effects under the control diet, but that its effects were blunted or even reversed under the HF/HFr diet. CN supplementation could be beneficial under a standard diet. [corrected].

Sex-specific programming of hypertension in offspring of late-gestation diabetic rats

BACKGROUND

The intrauterine environment strongly influences adult disease susceptibility. We used a rat model of third-trimester maternal diabetes to test the hypothesis that adult offspring exposed to hyperglycemia in utero display increased blood pressure and alterations in vascular responsiveness.

METHODS

Diabetes was induced by streptozotocin injection to pregnant rats on gestation day 13 (term 21 d) and partially controlled with insulin injections. Hemodynamic function was evaluated in 6-12-mo-old offspring.

RESULTS

Male but not female offspring of diabetic mothers (ODM) had significantly increased blood pressure as compared with controls; heart rate (HR) was similar. For both sexes, HR baroreflex responses were similar as were in vivo hemodynamic responses to angiotensin II, nitric oxide synthase inhibition, and ganglionic blockade. Aortic contractility to angiotensin II was similar in the two groups. Nitric oxide synthase inhibition and the Cu/Zn superoxide dismutase inhibitor diethyldithiocarbamate, but not the superoxide dismutase-mimetic Tempol, significantly increased contractile responses to angiotensin II in controls but not ODM. Reduced nicotinamide adenine dinucleotide phosphate-stimulated superoxide production was greater in male ODM than in controls (P < 0.05).

CONCLUSION

Exposure to hyperglycemia in utero results in sex-specific cardiovascular changes in adult offspring. Impaired nitric oxide-reactive oxygen species signaling may play a significant role in the hemodynamic phenotype of ODM.

Oxidative stress contributes to sex differences in blood pressure in adult growth-restricted offspring

Numerous experimental studies suggest that oxidative stress contributes to the pathophysiology of hypertension and, importantly, that oxidative stress plays a more definitive role in mediating hypertension in males than in females. Intrauterine growth restriction induced by reduced uterine perfusion initiated at day 14 of gestation in the rat programs hypertension in adult male growth-restricted offspring; yet, female growth-restricted offspring are normotensive. The mechanisms mediating sex differences in blood pressure in adult growth-restricted offspring are not clear. Thus, this study tested the hypothesis that sex-specific differences in renal oxidative stress contribute to the regulation of blood pressure in adult growth-restricted offspring. A significant increase in blood pressure measured by telemetry in male growth-restricted offspring (P<0.05) was associated with a marked increase in renal markers of oxidative stress (P<0.05). Chronic treatment with the antioxidant Tempol had no effect on blood pressure in male control offspring, but it normalized blood pressure (P<0.05) and renal markers of oxidative stress (P<0.05) in male growth-restricted offspring relative to male control offspring. Renal markers of oxidative stress were not elevated in female growth-restricted offspring; however, renal activity of the antioxidant catalase was significantly elevated relative to female control offspring (P<0.05). Chronic treatment with Tempol did not significantly alter oxidative stress or blood pressure measured by telemetry in female offspring. Thus, these data suggest that sex differences in renal oxidative stress and antioxidant activity are present in adult growth-restricted offspring and that oxidative stress may play a more important role in modulating blood pressure in male but not female growth-restricted offspring.

Dexamethasone enhances oxidative stress-induced cell death in murine neural stem cells

Glucocorticoids (GCs) are essential for normal brain development; however, there is consistent evidence that prenatal exposure of the fetal brain to excess GCs permanently modifies the phenotype of neuronal cells. In this paper, the murine-derived multipotent stem cell line C17.2 was used, as an in vitro model, to investigate the impact of GCs on neural stem cell survival. Our results indicate that dexamethasone (Dex) increases the sensitivity of murine neural stem cells (NSCs) to 2,3-methoxy-1,4-naphthoquinone-induced apoptosis, and this effect could be blocked by the glucocorticoid-receptor (GR) antagonist mifepristone, strongly suggesting the involvement of the GR. Furthermore, our results show that Dex decreases cell number and induces a G1-arrest. We hypothesized that the mitochondria are the main target of Dex. Interestingly, after treatment with Dex, 72% of the investigated genes involved in the mitochondrial respiratory chain are down-regulated, as well as 29% of the genes encoding for antioxidant enzymes. In conclusion, using the C17.2 cell line as a model to study developmental neurotoxicity in vitro, we have shown that GCs can increase cellular sensitivity to oxidative stress and alter the phenotype of NCSs.

Developmental programming of adult obesity and cardiovascular disease in rodents by maternal nutrition imbalance

Studies on fetal undernutrition have generated the hypothesis that fetal programming corresponds to an attempt of the fetus to adapt to adverse conditions encountered in utero. These adaptations would be beneficial if these conditions prevail later in life, but they become detrimental in the case of normal or plentiful nutrition and favor the appearance of the metabolic syndrome. In this article, the discussion is limited to the developmental programming of obesity and cardiovascular disorders caused by an early mismatched nutrition, particularly intrauterine growth retardation followed by postnatal catch-up growth. Selected data in humans are reviewed before evoking some mechanisms revealed or suggested by experiments in rodents. A variety of physiologic mechanisms are implicated in obesity programming, 2 of which are detailed. In some, but not all observations, hyperphagia resulting namely from perturbed development of the hypothalamic circuitry devoted to appetite regulation may contribute to obesity. Another contribution may be the developmental changes in the population of fat cell precursors in adipose tissue. Even if the link between obesity and cardiovascular disease is well established, alteration of blood pressure regulation may appear independently of obesity. A loss of diurnal variation in heart rate and blood pressure in adulthood has resulted from maternal undernutrition followed by postnatal overnutrition. Further research should clarify the effect of mismatched early nutrition on the development of brain centers regulating energy intake, energy expenditure, and circadian rhythms.

The maternal intrauterine environment as a generator of children at risk of metabolic syndrome: a review

Nowadays, scientists are paying special attention to the increasing prevalence of obesity and associated co-morbidities, especially metabolic syndrome. This is due to observation of the spread of this syndrome from one generation to another and the growing number of obese pregnant women, which seems to exacerbate this situation. It is not yet well established whether the pathophysiological process underlying metabolic syndrome, namely insulin resistance, is due to changes in the receptor or in the cascade of intracellular processes. This narrative review aims to report on physiological and pathological changes occurring in pregnancy and the presence of Insulin receptor, Insulin Growth Factor-I receptor and the hybrid receptor, focusing on the presence of hyperinsulinemia in the growth and development of fetuses susceptible to metabolic syndrome.

Perinatal micronutrient supplements ameliorate hypertension and proteinuria in adult fawn-hooded hypertensive rats

BACKGROUND

In fawn-hooded hypertensive (FHH) rats, a model of hypertension, impaired preglomerular resistance, hyperfiltration, and progressive renal injury, we recently observed that supporting perinatal nitric oxide (NO) availability with the NO donor molsidomine persistently reduced blood pressure (BP) and ameliorated renal injury in male and female offspring. However, beneficial effects of perinatal molsidomine treatment were more pronounced in female than in male FHH rats.

METHODS

To evaluate whether such protective effects could also be achieved with micronutrients, and whether the gender-dependent differences could be confirmed, we tested perinatal exposure to the micronutrients L-arginine, taurine, vitamin C, and vitamin E (ATCE) in FHH rats. Perinatal micronutrients increased urinary NO metabolite, sodium and potassium excretion only at 4 weeks of age, i.e., at the end of treatment.

RESULTS

From 12 weeks onwards, control males had a significantly higher systolic BP (SBP) than females (P < 0.01); however after perinatal micronutrients, this difference was no longer present, indicating a pronounced antihypertensive effect of perinatal micronutrients in males (interaction P < 0.001). Development of proteinuria was attenuated by perinatal micronutrients in males and females. However, only females showed reduced glomerular filtration rate, filtration fraction, and glomerulosclerosis (GS) after perinatal micronutrients.

CONCLUSIONS

In sum, perinatal micronutrients that enhance NO availability ameliorated development of hypertension and proteinuria in FHH rats. Antihypertensive effects were more pronounced in male FHH offspring, whereas renal protective effects were more pronounced in female FHH offspring. Mechanisms underlying gender-specific consequences of perinatal micronutrients require further study.

Maternal obesity and markers of inflammation in pregnancy

OBJECTIVES

To evaluate whether obesity is associated with changes in pro-inflammatory and immunomodulatory cytokines in pregnancy.

METHODS

We performed a cross-sectional study using maternal serum from the early second trimester to examine biomarkers associated with inflammation in relation to maternal body mass index (n=80 total).

RESULTS

Leptin and high sensitivity C-reactive protein were significantly different between groups and increased with increasing body mass index. MCP-1 was significantly increased in the morbidly obese mothers. Interleukin-2 exhibited a U-shaped relationship with body mass index; transforming growth factor-beta1 demonstrated a nonsignificant negative trend with body mass index; and the levels of hepatocyte growth factor and tumor necrosis factor-alpha did not differ appreciably between groups.

CONCLUSIONS

Maternal obesity in pregnancy is associated with changes in cytokines, protein hormones and acute phase proteins in the second trimester, with an increase in MCP-1 in the morbid obesity category, and an increase in Leptin and hsCRP with increasing BMI category.

Maternal prenatal undernutrition alters the response of POMC neurons to energy status variation in adult male rat offspring

Epidemiological studies suggest that maternal undernutrition predisposes the offspring to development of energy balance metabolic pathologies in adulthood. Using a model of a prenatal maternal 70% food-restricted diet (FR30) in rats, we evaluated peripheral parameters involved in nutritional regulation, as well as the hypothalamic appetite-regulatory system, in nonfasted and 48-h-fasted adult offspring. Despite comparable glycemia in both groups, mild glucose intolerance, with a defect in glucose-induced insulin secretion, was observed in FR30 animals. They also exhibited hyperleptinemia, despite similar visible fat deposits. Using semiquantitative RT-PCR, we observed no basal difference of hypothalamic proopiomelanocortin (POMC) and neuropeptide Y (NPY) gene expression, but a decrease of the OB-Rb and an increase of insulin receptor mRNA levels, in FR30 animals. These animals also exhibited basal hypercorticosteronemia and a blunted increase of corticosterone in fasted compared with control animals. After fasting, FR30 animals showed no marked reduction of POMC mRNA levels or intensity of beta-endorphin-immunoreactive fiber projections. By contrast, NPY gene expression and immunoreactive fiber intensity increased. FR30 rats also displayed subtle alterations of food intake: body weight-related food intake was higher and light-dark phase rhythm and refeeding time course were modified after fasting. At rest, in the morning, hyperinsulinemia and a striking increase in the number of c-Fos-containing cells in the arcuate nucleus were observed. About 30% of the c-Fos-expressing cells were POMC neurons. Our data suggest that maternal undernutrition differently programs the long-term appetite-regulatory system of offspring, especially the response of POMC neurons to energy status and food intake rhythm.

Pediatric Obesity: It's Time for Prevention before Conception Can Maternal Obesity Program Pediatric Obesity?

Global increases in obesity have led public health experts to declare this disease a pandemic. Although prevalent in all ages, the dire consequences associated with maternal obesity have a pronounced impact on the long-term health of their children as a result of the intergenerational effects of developmental programming. Previously, fetal under-nutrition has been linked to the predisposition to pediatric obesity explained by the adiposity rebound and ‘catch-up’ growth that occurs when a child born to a nutrient deprived mother is exposed to the obesogenic environment of present day. Given the recent increase in maternal overweight/obesity (OW/OB) our attention has shifted from nutrient restriction to overabundance and excess during pregnancy. Consideration must now be given to interventions that could mitigate pregravid body mass index (BMI), attenuate gestational weight gain (GWG) and reduce postpartum weight retention (PPWR) in an attempt to prevent the downstream signaling of pediatric obesity and halt the intergenerational cycle of weight related disease currently plaguing our world. Thus, this paper will briefly review current research that best highlights the proposed mechanisms responsible for the development of child OW/OB and related sequalae (e.g. type II diabetes (T2D) and cardiovascular disease (CVD)) resulting from maternal obesity.

Cardiovascular and metabolic effects of obesity

1. Obesity is an important risk factor for hypertension and its incidence is increasing around the world. 2. The mechanisms underlying obesity-related hypertension include sympathetic activation, altered vascular responses, hormonal changes, enhanced inflammatory markers and structural changes. 3. This review summarizes recent evidence of the underlying impact of obesity on blood pressure. A number of candidate mechanisms include increased sympathetic activity, activation of the renin-angiotensin system, altered vasoconstrictor or dilator responses and the attendant systemic inflammatory state. 4. While adult lifestyle factors undoubtedly contribute to the incidence of obesity and its attendant hypertension, evidence suggests that the programming of obesity may occur following over-nutrition during development. A growing body of evidence links maternal obesity, offspring obesity and hypertension. 5. Finally, epigenetic modification of genes relevant to hypertension may contribute to the development of hypertension following a suboptimal intrauterine environment. To date the cardiovascular effects of early nutritional changes have been largely investigated following maternal under-nutrition or protein restriction; further work is necessary to determine the impact of maternal obesity.