Developmental programming and hypertension

Obese Male Mice Exposed to Early Life Stress Display Sympathetic Activation and Hypertension Independent of Circulating Angiotensin II

BACKGROUND

We have previously reported that male mice exposed to maternal separation and early weaning (MSEW), a model of early life stress, show sympathetic activation and increased blood pressure in response to a chronic high-fat diet. The goal of this study was to investigate the contribution of the renin-angiotensin-aldosterone system to the mechanism by which MSEW increases blood pressure and vasomotor sympathetic tone in obese male mice.

METHODS AND RESULTS

Mice were exposed to MSEW during postnatal life. Undisturbed litters served as controls. At weaning, both control and MSEW offspring were placed on a low-fat diet or a high-fat diet for 20 weeks. Angiotensin peptides in serum were similar in control and MSEW mice regardless of the diet. However, a high-fat diet induced a similar increase in angiotensinogen levels in serum, renal cortex, liver, and fat in both control and MSEW mice. No evidence of renin-angiotensin system activation was found in adipose tissue and renal cortex. After chronic treatment with enalapril (2.5 mg/kg per day, drinking water, 7 days), an angiotensin-converting enzyme inhibitor that does not cross the blood-brain barrier, induced a similar reduction in blood pressure in both groups, while the vasomotor sympathetic tone remained increased in obese MSEW mice. In addition, acute boluses of angiotensin II (1, 10, 50 μg/kg s.c.) exerted a similar pressor response in MSEW and control mice before and after enalapril treatment.

CONCLUSIONS

Overall, elevated blood pressure and vasomotor sympathetic tone remained exacerbated in MSEW mice compared with controls after the peripheral inhibition of angiotensin-converting enzyme, suggesting a mechanism independent of angiotensin II.

Albuminuria and markers for cardiovascular risk in 12-year-olds from the general Dutch population: a cross-sectional study

In adults, albuminuria represents a risk factor for cardiovascular disease and is associated with hypertension and obesity. Pediatric data from the general population are inconsistent and largely based on randomly collected urine. A possible association between antenatal programming and albuminuria at school age has still to be investigated. The purpose of this study is to assess albuminuria in first morning void urine samples in a population-based pediatric cohort and to investigate cross-sectionally the association with factors related to cardiovascular risk. Moreover, we investigate the possible association of antenatal factors with albuminuria. A first morning void urine sample was collected in the population-based GECKO (Groningen Expert Center for Kids with Obesity) Drenthe cohort at the age of 12 years. We investigated cross-sectionally associations between albuminuria and body mass index (BMI), waist circumference (WC), blood pressure (BP) and antenatal factors. The prevalence of UACR (urinary albumin-creatinine ratio) ≥ 3 mg/mmol was 3.3% (95%CI 2.3-4.2). In a multivariate linear regression model, UAC was negatively associated with z-BMI (β-0.08, p = 0.013) and positively with z-systolic BP (β 0.09, p = 0.006), model significance p = 0.002. UACR was negatively associated with z-BMI (β - 0.13, p < 0.001) and positively with z-diastolic BP (β 0.09, p = 0.003), model significance p = 0.001. Albuminuria was not significantly associated with antenatal factors such as gestational age and standardized birth weight.

CONCLUSIONS

 Albuminuria in first morning void urine in 12-year-olds has a lower prevalence than previously reported by randomly collected samples. A negative association between albuminuria and BMI is confirmed. A positive association with blood pressure, but no association with antenatal factors was found.

WHAT IS KNOWN

• While, in adults, albuminuria is a recognized risk factor for cardiovascular disease and is associated with hypertension and obesity, pediatric data are inconsistent and largely based on randomly collected urine. • A possible association between antenatal programming and albuminuria at school age has still to be investigated.

WHAT IS NEW

• In this population study on first morning void urine samples from 12-year-olds of the general population, albuminuria is negatively associated with body mass index, and positively associated with blood pressure, while there is no association with antenatal factors. • The prevalence of albuminuria at 12 years is lower than previously reported in studies based on randomly collected urine samples, probably due to elimination of orthostatic proteinuria.

Effects of Gestational Hypoxia on PGC1α and Mitochondrial Acetylation in Fetal Guinea Pig Hearts

Chronic intrauterine hypoxia is a significant pregnancy complication impacting fetal heart growth, metabolism, and mitochondrial function, contributing to cardiovascular programming of the offspring. PGC1α (peroxisome proliferator-activated receptor γ co-activator 1α) is the master regulator of mitochondrial biogenesis. We investigated the effects of hypoxia on PGC1α expression following exposure at different gestational ages. Time-mated pregnant guinea pigs were exposed to normoxia (NMX, 21% O2) or hypoxia (HPX, 10.5% O2) at either 25-day (early-onset) or 50-day (late-onset) gestation, and all fetuses were extracted at term (term = ~65-day gestation). Expression of nuclear PGC1α, sirtuin 1 (SIRT1), AMP-activated protein kinase (AMPK), and mitochondrial sirtuin 3 (SIRT3) was measured, along with SIRT3 activity and mitochondrial acetylation of heart ventricles of male and female fetuses. Early-onset hypoxia increased (P<0.05) fetal cardiac nuclear PGC1α and had no effect on mitochondrial acetylation of either growth-restricted males or females. Late-onset hypoxia had either no effect or decreased (P<0.05) PCC1α expression in males and females, respectively, but increased (P<0.05) mitochondrial acetylation in both sexes. Hypoxia had variable effects on expression of SIRT1, AMPK, SIRT3, and SIRT3 activity depending on the sex. The capacity of the fetal heart to respond to hypoxia differs depending on the gestational age of exposure and sex of the fetus. Further, the effects of late-onset hypoxia on fetal heart function impose a greater risk to male than female fetuses, which has implications toward cardiovascular programming effects of the offspring.

The co-occurrence and cumulative prevalence of hypertension, rheumatoid arthritis, and hypothyroidism in preterm-born women in the Women's Health Initiative

Emerging evidence suggests that preterm-born individuals (<37 weeks gestation) are at increased risk of developing chronic health conditions in adulthood. This study compared the prevalence, co-occurrence, and cumulative prevalence of three female predominant chronic health conditions - hypertension, rheumatoid arthritis [RA], and hypothyroidism - alone and concurrently. Of 82,514 U.S. women aged 50-79 years enrolled in the Women's Health Initiative, 2,303 self-reported being born preterm. Logistic regression was used to analyze the prevalence of each condition at enrollment with birth status (preterm, full term). Multinomial logistic regression models analyzed the association between birth status and each condition alone and concurrently. Outcome variables using the 3 conditions were created to give 8 categories ranging from no disease, each condition alone, two-way combinations, to having all three conditions. The models adjusted for age, race/ethnicity, and sociodemographic, lifestyle, and other health-related risk factors. Women born preterm were significantly more likely to have any one or a combination of the selected conditions. In fully adjusted models for individual conditions, the adjusted odds ratios (aORs) were 1.14 (95% CI, 1.04, 1.26) for hypertension, 1.28 (1.12, 1.47) for RA, and 1.12 (1.01, 1.24) for hypothyroidism. Hypothyroidism and RA were the strongest coexisting conditions [aOR 1.69, 95% CI (1.14, 2.51)], followed by hypertension and RA [aOR 1.48, 95% CI (1.20, 1.82)]. The aOR for all three conditions was 1.69 (1.22, 2.35). Perinatal history is pertinent across the life course. Preventive measures and early identification of risk factors and disease in preterm-born individuals are essential to mitigating adverse health outcomes in adulthood.

Cardiometabolic Effects of Postnatal High-Fat Diet Consumption in Offspring Exposed to Maternal Protein Restriction In Utero

In recent decades, the high incidence of infectious and parasitic diseases has been replaced by a high prevalence of chronic and degenerative diseases. Concomitantly, there have been profound changes in the behavior and eating habits of families around the world, characterizing a “nutritional transition” phenomenon, which refers to a shift in diet in response to modernization, urbanization, or economic development from undernutrition to the excessive consumption of hypercaloric and ultra-processed foods. Protein malnutrition that was a health problem in the first half of the 20th century has now been replaced by high-fat diets, especially diets high in saturated fat, predisposing consumers to overweight and obesity. This panorama points us to the alarming coexistence of both malnutrition and obesity in the same population. In this way, individuals whose mothers were undernourished early in pregnancy and then exposed to postnatal hyperlipidic nutrition have increased risk factors for developing metabolic dysfunction and cardiovascular diseases in adulthood. Thus, our major aim was to review the cardiometabolic effects resulting from postnatal hyperlipidic diets in protein-restricted subjects, as well as to examine the epigenetic repercussions occasioned by the nutritional transition.

Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm

Progressive improvements in perinatal care and respiratory management of preterm infants have resulted in increased survival of newborns of extremely low gestational age over the past few decades. However, the incidence of bronchopulmonary dysplasia, the chronic lung disease after preterm birth, has not changed. Studies of the long-term follow-up of adults born preterm have shown persistent abnormalities of respiratory, cardiovascular and cardiopulmonary function, possibly leading to a lower exercise capacity. The underlying causes of these abnormalities are incompletely known, but we hypothesize that dysanapsis, i.e. discordant growth and development, in the respiratory and cardiovascular systems is a central structural feature that leads to a lower exercise capacity in young adults born preterm than those born at term. We discuss how the hypothesized system dysanapsis underscores the observed respiratory, cardiovascular and cardiopulmonary limitations. Specifically, adults born preterm have: (1) normal lung volumes but smaller airways, which causes expiratory airflow limitation and abnormal respiratory mechanics but without impacts on pulmonary gas exchange efficiency; (2) normal total cardiac size but smaller cardiac chambers; and (3) in some cases, evidence of pulmonary hypertension, particularly during exercise, suggesting a reduced pulmonary vascular capacity despite reduced cardiac output. We speculate that these underlying developmental abnormalities may accelerate the normal age-associated decline in exercise capacity, via an accelerated decline in respiratory, cardiovascular and cardiopulmonary function. Finally, we suggest areas of future research, especially the need for longitudinal and interventional studies from infancy into adulthood to better understand how preterm birth alters exercise capacity across the lifespan.

Chronic hypoxia alters cardiac mitochondrial complex protein expression and activity in fetal guinea pigs in a sex-selective manner

We hypothesize that intrauterine hypoxia (HPX) alters the mitochondrial phenotype in fetal hearts contributing to developmental programming. Pregnant guinea pigs were exposed to normoxia (NMX) or hypoxia (HPX, 10.5% O2), starting at early [25 days (25d), 39d duration] or late gestation (50d, 14d duration). Near-term (64d) male and female fetuses were delivered by hysterotomy from anesthetized sows, and body/organ weights were measured. Left ventricles of fetal hearts were excised and frozen for measurement of expression of complex (I-V) subunits, fusion (Mfn2/OPA1) and fission (DRP1/Fis1) proteins, and enzymatic rates of I and IV from isolated mitochondrial proteins. Chronic HPX decreased fetal body weight and increased relative placenta weight regardless of timing. Early-onset HPX increased I, III, and V subunit levels, increased complex I but decreased IV activities in males but not females (all P < 0.05). Late-onset HPX decreased (P < 0.05) I, III, and V levels in both sexes but increased I and decreased IV activities in males only. Both HPX conditions decreased cardiac mitochondrial DNA content in males only. Neither early- nor late-onset HPX had any effect on Mfn2 levels but increased OPA1 in both sexes. Both HPX treatments increased DRP1/Fis1 levels in males. In females, early-onset HPX increased DRP1 with no effect on Fis1, whereas late-onset HPX increased Fis1 with no effect on DRP1. We conclude that both early- and late-onset HPX disrupts the expression/activities of select complexes that could reduce respiratory efficiency and shifts dynamics toward fission in fetal hearts. Thus, intrauterine HPX disrupts the mitochondrial phenotype predominantly in male fetal hearts, potentially altering cardiac metabolism and predisposing the offspring to heart dysfunction.

Safety, Feasibility, and Impact of Enalapril on Cardiorespiratory Physiology and Health in Preterm Infants with Systemic Hypertension and Left Ventricular Diastolic Dysfunction

Neonatal hypertension has been increasingly recognized in premature infants with bronchopulmonary dysplasia (BPD); of note, a sub-population of these infants may have impaired left ventricular (LV) diastolic function, warranting timely treatment to minimize long term repercussions. In this case series, enalapril, an angiotensin-converting enzyme (ACE) inhibitor, was started in neonates with systemic hypertension and echocardiography signs of LV diastolic dysfunction. A total of 11 patients were included with birth weight of 785 ± 239 grams and gestational age of 25.3 (24, 26.1) weeks. Blood pressure improvement was noticed within 2 weeks of treatment. Improvement in LV diastolic function indices were observed with a reduction in Isovolumic Relaxation Time (IVRT) from 63.1 ± 7.2 to 50.9 ± 7.4 msec and improvement in the left atrium size indexed to aorta (LA:Ao) from1.73 (1.43, 1.88) to 1.23 (1.07, 1.29). Neonatal systemic hypertension is often underappreciated in ex-preterm infants and may be associated with important maladaptive cardiac changes with long term implications. It is biologically plausible that identifying and treating LV diastolic dysfunction in neonates with systemic hypertension may have a positive modulator effect on cardiovascular health in childhood and beyond.

Impact of very preterm birth and post-discharge growth on cardiometabolic outcomes at school age: a retrospective cohort study

Background

Adverse metabolic outcomes later in life have been reported among children or young adults who were born as preterm infants. This study was conducted to examine the impact of very preterm/very low birth weight (VP/VLBW) birth and subsequent growth after hospital discharge on cardiometabolic outcomes such as insulin resistance, fasting glucose, and systolic and diastolic blood pressure (BP) among children at 6–8 years of age.

Methods

This retrospective cohort study included children aged 6–8 years and compared those who were born at < 32 weeks of gestation or weighing < 1,500 g at birth (n = 60) with those born at term (n = 110). Body size, fat mass, BP, glucose, insulin, leptin, adiponectin, and lipid profiles were measured. Weight-for-age z-score changes between discharge and early school-age period were also calculated, and factors associated with BP, fasting glucose, and insulin resistance were analyzed.

Results

Children who were born VP/VLBW had significantly lower fat masses, higher systolic BP and diastolic BP, and significantly higher values of fasting glucose, insulin, and homeostatic model assessment of insulin resistance (HOMA-IR), compared to children born at term. VP/VLBW was correlated with HOMA-IR and BPs after adjusting for various factors, including fat mass index and weight-for-age z-score changes. Weight-for-age z-score changes were associated with HOMA-IR, but not with BPs.

Conclusions

Although children aged 6–8 years who were born VP/VLBW showed significantly lower weight and fat mass, they had significantly higher BPs, fasting glucose, HOMA-IR, and leptin levels. The associations of VP/VLBW with cardiometabolic factors were independent of fat mass and weight gain velocity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02851-5.

Quantifying Fetal Reprogramming for Biomarker Development in the Era of High-Throughput Sequencing

Gestational hypertensive disorders continue to threaten the well-being of pregnant women and their offspring. The only current definitive treatment for gestational hypertensive disorders is delivery of the fetus. The optimal timing of delivery remains controversial. Currently, the available clinical tools do not allow for assessment of fetal stress in its early stages. Placental insufficiency and fetal growth restriction secondary to gestational hypertensive disorders have been shown to have long-term impacts on offspring health even into their adulthood, becoming one of the major focuses of research in the field of developmental origins of health and disease. Fetal reprogramming was introduced to describe the long-lasting effects of the toxic intrauterine environment on the growing fetus. With the advent of high-throughput sequencing, there have been major advances in research attempting to quantify fetal reprogramming. Moreover, genes that are found to be differentially expressed as a result of fetal reprogramming show promise in the development of transcriptional biomarkers for clinical use in detecting fetal response to placental insufficiency. In this review, we will review key pathophysiology in the development of placental insufficiency, existing literature on high-throughput sequencing in the study of fetal reprogramming, and considerations regarding research design from our own experience.

Salt and Sugar: Two Enemies of Healthy Blood Pressure in Children

The prevalence of essential arterial hypertension in children and adolescents has grown considerably in the last few decades, making this disease a major clinical problem in the pediatric age. The pathogenesis of arterial hypertension is multifactorial, with one of the components being represented by incorrect eating habits. In particular, excessive salt and sugar intake can contribute to the onset of hypertension in children, particularly in subjects with excess weight. Babies have an innate predisposition for sweet taste, while that for salty taste manifests after a few weeks. The recent modification of dietary styles and the current very wide availability of salt and sugar has led to an exponential increase in the consumption of these two nutrients. The dietary intake of salt and sugar in children is in fact much higher than that recommended by health agencies. The purpose of this review is to explore the mechanisms via which an excessive dietary intake of salt and sugar can contribute to the onset of arterial hypertension in children and to show the most important clinical studies that demonstrate the association between these two nutrients and arterial hypertension in pediatric age. Correct eating habits are essential for the prevention and nondrug treatment of essential hypertension in children and adolescents.

Persistent Aortic Stiffness and Left Ventricular Hypertrophy in Children of Diabetic Mothers

Background

Fetuses of diabetic mothers develop left ventricular (LV) hypertrophy and are at increased long-term risk of cardiovascular disease. In our previous longitudinal study from midgestation to late infancy we showed persistence of LV hypertrophy and increased aortic stiffness compared with infants of healthy mothers, the latter of which correlated with third trimester maternal hemoglobin A1c. In the present study, we reexamined the same cohort in early childhood to determine if these cardiovascular abnormalities persisted.

Methods

Height, weight, and right arm blood pressure were recorded. A full functional and structural echocardiogram was performed with offline analysis of LV posterior wall and interventricular septal diastolic thickness (IVSd), systolic and diastolic function, and aortic pulse wave velocity. Vascular reactivity was assessed using digital thermal monitoring. Participants also completed a physical activity questionnaire.

Results

Twenty-five children of diabetic mothers (CDMs) and 20 children from healthy pregnancies (mean age, 5.6 ± 1.7 and 5.3 ± 1.3 years, respectively; P = not significant) were assessed. Compared with controls, IVSd z score was increased in CDMs (1.2 ± 0.6 vs 0.5 ± 0.3, respectively; P = 0.006), with one-fifth having a z score of more than +2.0. Aortic pulse wave velocity was increased in CDMs (3.2 ± 0.6 m/s vs 2.2 ± 0.4 m/s; P = 0.001), and correlated with IVSd z score (R² = 0.81; P = 0.001) and third trimester maternal A1c (R² = 0.65; P < 0.0001). Body surface area, height, weight, blood pressure, vascular reactivity, and physical activity scores did not differ between groups. Our longitudinal analysis showed that individuals with greater IVSd, and aortic stiffness in utero, early and late infancy also tended to have greater measures in early childhood (P < 0.001 and P < 0.0001, respectively).

Conclusions

CDMs show persistently increased interventricular septal thickness and aortic stiffness in early childhood.

Factors Predisposing to Hypertension in Subjects Formerly Born Preterm: Renal Impairment, Arterial Stiffness, Endothelial Dysfunction or Something Else?

Subjects formerly born preterm subsequently develop arterial - particularly isolated systolic- hypertension more frequently than their peers born at term.

Numerous factors may influence this predisposition, including an incomplete nephrogenesis, implying the presence of kidneys with a reduced number of nephrons and consequent reduction in haematic filtration, increased sodium absorption and activation of renin-angiotensin-aldosterone system, increased arterial rigidity produced by an elastin deficiency previously observed in anatomic specimens of human immature aorta, and reduced endothelial nitric oxide excretion, due to high blood levels of ADMA, a strong direct inhibitor of nitric oxide that exerts a vasoconstrictor effect.

Other possible factors (i.e. excretion of neuroendocrine compounds) may also be implicated. The aim of this paper was to review all possible mechanisms involved in the observed increase in blood pressure in individuals who had been born preterm and/or with intrauterine growth restriction. The outlook for new and promising laboratory techniques capable of identifying alterations in the metabolic pathways regulating blood pressure levels, such as metabolomics, is also provided.

Elevated blood pressure in high-fat diet-exposed low birthweight rat offspring is most likely caused by elevated glucocorticoid levels due to abnormal pituitary negative feedback

Being delivered as a low birthweight (LBW) infant is a risk factor for elevated blood pressure and future problems with cardiovascular and cerebellar diseases. Although premature babies are reported to have low numbers of nephrons, some unclear questions remain about the mechanisms underlying elevated blood pressure in full-term LBW infants. We previously reported that glucocorticoids increased miR-449a expression, and increased miR-449a expression suppressed Crhr1 expression and caused negative glucocorticoid feedback. Therefore, we conducted this study to clarify the involvement of pituitary miR-449a in the increase in blood pressure caused by higher glucocorticoids in LBW rats. We generated a fetal low-carbohydrate and calorie-restricted model rat (60% of standard chow), and some individuals showed postnatal growth failure caused by growth hormone receptor expression. Using this model, we examined how a high-fat diet (lard-based 45kcal% fat)-induced mismatch between prenatal and postnatal environments could elevate blood pressure after growth. Although LBW rats fed standard chow had slightly higher blood pressure than control rats, their blood pressure was significantly higher than controls when exposed to a high-fat diet. Observation of glomeruli subjected to periodic acid methenamine silver (PAM) staining showed no difference in number or size. Aortic and cardiac angiotensin II receptor expression was altered with compensatory responses. Blood aldosterone levels were not different between control and LBW rats, but blood corticosterone levels were significantly higher in the latter with high-fat diet exposure. Administration of metyrapone, a steroid synthesis inhibitor, reduced blood pressure to levels comparable to controls. We showed that high-fat diet exposure causes impairment of the pituitary glucocorticoid negative feedback via miR-449a. These results clarify that LBW rats have increased blood pressure due to high glucocorticoid levels when they are exposed to a high-fat diet. These findings suggest a new therapeutic target for hypertension of LBW individuals.

Hypertension Programmed in Adult Hens by Isolated Effects of Developmental Hypoxia In Ovo

In mammals, pregnancy complicated by chronic hypoxia can program hypertension in the adult offspring. However, mechanisms remain uncertain because the partial contributions of the challenge on the placenta, mother, and fetus are difficult to disentangle. Here, we used chronic hypoxia in the chicken embryo-an established model system that permits isolation of the direct effects of developmental hypoxia on the cardiovascular system of the offspring, independent of additional effects on the mother or the placenta. Fertilized chicken eggs were exposed to normoxia (N; 21% O₂) or hypoxia (H; 13.5%-14% O₂) from the start of incubation (day 0) until day 19 (hatching, ≈day 21). Following hatching, all birds were maintained under normoxic conditions until ≈6 months of adulthood. Hypoxic incubation increased hematocrit (+27%) in the chicken embryo and induced asymmetrical growth restriction (body weight, -8.6%; biparietal diameter/body weight ratio, +7.5%) in the hatchlings (all P<0.05). At adulthood (181±4 days), chickens from hypoxic incubations remained smaller (body weight, -7.5%) and showed reduced basal and stimulated in vivo NO bioavailability (pressor response to NG-nitro-L-arginine methyl ester, -43%; phenylephrine pressor response during NO blockade, -61%) with significant hypertension (mean arterial blood pressure, +18%), increased cardiac work (ejection fraction, +12%; fractional shortening, +25%; enhanced baroreflex gain, +456%), and left ventricular wall thickening (left ventricular wall volume, +36%; all P<0.05). Therefore, we show that chronic hypoxia can act directly on a developing embryo to program hypertension, cardiovascular dysfunction, and cardiac wall remodeling in adulthood in the absence of any maternal or placental effects.

The mediation effect of anthropometry and physical fitness on the relationship between birthweight and basal metabolic rate in children

BACKGROUND

Birthweight (BW) has been associated with anthropometry, body composition and physical fitness during growth and development of children. However, less is known about the mediation effect of those variables on the relationship between BW and basal metabolic rate (BMR) in children.

OBJECTIVE

To analyse the mediation effect of anthropometry, body composition and physical fitness on the association between BW and BMR in children.

METHODS

In total, 499 children (254 boys, 245 girls) aged 7-10 years were included. Anthropometry (weight, height, head, waist and hip circumferences), body composition (skinfolds thickness, body fat percentage), physical fitness (handgrip strength, flexibility, muscular endurance, muscular explosive power, agility, running speed) and BMR were evaluated. The analyses were conducted by: single-mediator analysis (SMA) and multi-mediator analysis (MMA).

RESULTS

The SMA indicates height, head, waist and hip circumferences and handgrip strength as significant mediators of BW on BMR for boys and height, hip circumference and handgrip strength as significant mediators of BW on BMR for girls. In MMA for girls, there were significant indirect effects for height, hip circumference and handgrip strength, with 79.08% of percent mediation. For boys, the head and waist circumferences mediation had a significant indirect effect, with 83.37% of percent mediation.

CONCLUSION

The anthropometric variables associated with BW were body height, head, hip and waist circumferences for boys and body height and hip circumference for girls. The current study provides new evidence that height and handgrip strength during childhood mediated the relationship between BW and BMR.

Epigenetic Biomarkers in Cardiovascular Diseases

Cardiovascular diseases are the number one cause of death worldwide and greatly impact quality of life and medical costs. Enormous effort has been made in research to obtain new tools for efficient and quick diagnosis and predicting the prognosis of these diseases. Discoveries of epigenetic mechanisms have related several pathologies, including cardiovascular diseases, to epigenetic dysregulation. This has implications on disease progression and is the basis for new preventive strategies. Advances in methodology and big data analysis have identified novel mechanisms and targets involved in numerous diseases, allowing more individualized epigenetic maps for personalized diagnosis and treatment. This paves the way for what is called pharmacoepigenetics, which predicts the drug response and develops a tailored therapy based on differences in the epigenetic basis of each patient. Similarly, epigenetic biomarkers have emerged as a promising instrument for the consistent diagnosis and prognosis of cardiovascular diseases. Their good accessibility and feasible methods of detection make them suitable for use in clinical practice. However, multicenter studies with a large sample population are required to determine with certainty which epigenetic biomarkers are reliable for clinical routine. Therefore, this review focuses on current discoveries regarding epigenetic biomarkers and its controversy aiming to improve the diagnosis, prognosis, and therapy in cardiovascular patients.

Maternal physical activity prevents the overexpression of hypoxia-inducible factor 1-α and cardiorespiratory dysfunction in protein malnourished rats

Maternal physical activity attenuates cardiorespiratory dysfunctions and transcriptional alterations presented by the carotid body (CB) of rats. Rats performed physical activity and were classified as inactive/active. During gestation and lactation, mothers received either normoprotein (NP-17% protein) or low-protein diet (LP-8% protein). In offspring, biochemical serum levels, respiratory parameters, cardiovascular parameters and the mRNA expression of hypoxia-inducible factor 1-alpha (HIF-1α), tyrosine hydroxylase (TH) and purinergic receptors were evaluate. LP-inactive pups presented lower RF from 1^st to 14^th days old, and higher RF at 30 days than did NP-inactive and NP-active pups. LP-inactive pups presented with reduced serum protein, albumin, cholesterol and triglycerides levels and an increased fasting glucose level compared to those of NP-inactive and NP-active groups. LP and LP-inactive animals showed an increase in the cardiac variability at the Low-Frequency bands, suggesting a major influence of sympathetic nervous activity. In mRNA analyses, LP-inactive animals showed increased HIF-1α expression and similar expression of TH and purinergic receptors in the CB compared to those of NP groups. All these changes observed in LP-inactive pups were reversed in the pups of active mothers (LP-active). Maternal physical activity is able to attenuate the metabolic, cardiorespiratory and HIF-1α transcription changes induced by protein malnutrition.

Clinical consequences of developmental programming of low nephron number

Nephron number in humans varies up to 13-fold, likely reflecting the impact of multiple factors on kidney development, including inherited body size and ethnicity, as well as maternal health and nutrition, fetal exposure to gestational diabetes or preeclampsia and other environmental factors, which may potentially be modifiable. Such conditions predispose to low or high offspring birth weight, growth restriction or preterm birth, which have all been associated with increased risks of higher blood pressures and/or kidney dysfunction in later life. Low birth weight, preterm birth, and intrauterine growth restriction are associated with reduced nephron numbers. Humans with hypertension and chronic kidney disease tend to have fewer nephrons than their counterparts with normal blood pressures or kidney function. A developmentally programmed reduction in nephron number therefore enhances an individual's susceptibility to hypertension and kidney disease in later life. A low nephron number at birth may not lead to kidney dysfunction alone except when severe, but in the face of superimposed acute or chronic kidney injury, a kidney endowed with fewer nephrons may be less able to adapt, and overt kidney disease may develop. Given that millions of babies are born either too small, too big or too soon each year, the population impact of altered renal programming is likely to be significant. Many gestational exposures are modifiable, therefore urgent attention is required to implement public health measures to optimize maternal, fetal, and child health, to prevent or mitigate the consequences of developmental programming, to improve the health future generations.

Advanced maternal age and the impact on maternal and offspring cardiovascular health

Delaying pregnancy, which is on the rise, may increase the risk of cardiovascular disease in both women and their children. The physiological mechanisms that lead to these effects are not fully understood but may involve inadequate adaptations of the maternal cardiovascular system to pregnancy. Indeed, there is abundant evidence in the literature that a fetus developing in a suboptimal in utero environment (such as in pregnancies complicated by fetal growth restriction, preterm birth, and/or preeclampsia) is at an increased risk of cardiovascular disease in adulthood, the developmental origins of health and disease theory. Although women of advanced age are at a significantly increased risk of pregnancy complications, there is limited information as to whether advanced maternal age constitutes an added stressor on the prenatal environment of the fetus, and whether or not this is secondary to impaired cardiovascular function during pregnancy. This review summarizes the current literature available on the impact of advanced maternal age on cardiovascular adaptations to pregnancy and the role of maternal age on long-term health risks for both the mother and offspring.

Fetal Programming and Sexual Dimorphism of Mitochondrial Protein Expression and Activity of Hearts of Prenatally Hypoxic Guinea Pig Offspring

Chronic intrauterine hypoxia is a programming stimulus of cardiovascular dysfunction. While the fetal heart adapts to the reduced oxygenation, the offspring heart becomes vulnerable to subsequent metabolic challenges as an adult. Cardiac mitochondria are key organelles responsible for an efficient energy supply but are subject to damage under hypoxic conditions. We propose that intrauterine hypoxia alters mitochondrial function as an underlying programming mechanism of contractile dysfunction in the offspring. Indices of mitochondrial function such as mitochondrial DNA content, Complex (C) I-V expression, and CI/CIV enzyme activity were measured in hearts of male and female offspring at 90 days old exposed to prenatal hypoxia (10.5% O2) for 14 d prior to term (65 d). Both left ventricular tissue and cardiomyocytes exhibited decreased mitochondrial DNA content, expression of CIV, and CI/CIV activity in male hearts. In female cardiomyocytes, hypoxia had no effect on protein expression of CI-CV nor on CI/CIV activity. This study suggests that chronic intrauterine hypoxia alters the intrinsic properties of select respiratory complexes as a programming mechanism of cardiac dysfunction in the offspring. Sex differences in mitochondrial function may underlie the increased vulnerability of age-matched males compared to females in cardiovascular disease and heart failure.

Renal impairment induced by prenatal exposure to angiotensin II in male rat offspring

Suboptimal conditions during prenatal ontogeny can impair development of several physiological systems and result in cardiometabolic diseases in adulthood. The kidney has been identified as one of the most sensitive organs for developmental programming, but underlying mechanisms are not fully understood. Therefore, in our study we explored the consequences of prenatally increased angiotensin II (Ang II) on the structural development of the kidney and its damage by infiltrated immune cells under normal diet and after an increased salt intake, as a second insult representing a lifestyle factor in humans. Female rats were implanted with osmotic mini-pumps continuously releasing Ang II of dose 2 µg/kg/h during last two weeks of pregnancy, whereas control females were sham operated. Immunohistological and ultrastructural evaluations of the kidneys and their infiltration with immune cells were performed in mature male progeny kept either on a standard or increased salt (2% NaCl) diet. Glomerular volume decreased and the cortical tubulointerstitial injury increased in the offspring prenatally exposed to Ang II with no additional effect of increased salt. Ultrastructural examination demonstrated degenerative changes in proximal tubules, mainly fewer and shorter microvilli in the brush border, enlarged mitochondria, and an increased number of lysosomes in the epithelial cells in the progeny prenatally exposed to Ang II. Moreover, the treatment resulted in increased infiltration of T-cells and macrophages in the renal cortex compared to controls. These changes paralleled with reduced numbers of cytotoxic T-cells in circulation and higher oxidative burst of neutrophils in the progeny of Ang II-treated mothers compared to controls. Altogether, results suggest that prenatally increased Ang II promoted infiltration of immune cells in the kidney and subsequent oxidative stress, which induced a damage of renal glomerular and tubular system entailing negative consequences on the cardiovascular system.

Impact statement

Suboptimal prenatal conditions can contribute to development of cardiovascular diseases and an altered renin-angiotensin-aldosterone system (RAAS) can be involved in the process. In our study, increased angiotensin II in pregnant female rats resulted in renal cortical interstitial damage, and renal ultrastructural changes in the glomeruli, the brush border of proximal tubules and mitochondria in mature male offspring. The treatment promoted infiltration of T cells and macrophages in the kidneys and primed an oxidative burst of circulating neutrophils, indicating a pro-inflammatory state in the progeny of angiotensin II-treated mothers. Deregulated RAAS of mothers is involved in developmental programming of hypertension in adult male offspring via damaging kidney morphology and function. These findings suggest that preventing the activation of RAAS and oxidative stress during perinatal development might protect against hypertension development in adult male progeny.

Maternal-Infant Supplementation with Small-Quantity Lipid-Based Nutrient Supplements Does Not Affect Child Blood Pressure at 4-6 Y in Ghana: Follow-up of a Randomized Trial

BACKGROUND

In the International Lipid-Based Nutrient Supplements (iLiNS)-DYAD-Ghana trial, prenatal small-quantity lipid-based nutrient supplements (LNSs) had a positive effect on birth weight. Birth weight may be inversely related to blood pressure (BP) later in life.

OBJECTIVES

We examined the effect of the intervention on BP at 4-6 y of age, and maternal and child factors related to BP.

METHODS

The iLiNS-DYAD-Ghana study was a partially double-blind, randomized controlled trial which assigned women (n = 1320) ≤20 weeks of gestation to daily supplementation with: 1) iron and folic acid during pregnancy and 200 mg Ca for 6 mo postpartum , 2) multiple micronutrients during pregnancy and postpartum, or 3) LNSs during pregnancy and postpartum plus LNSs for infants from 6 to 18 mo of age. At 4-6 y of age (n = 858, 70% of live births), we compared BP, a secondary outcome, between non-LNS and LNS groups and examined whether BP was related to several factors including maternal BP, child weight-for-age z score (WAZ), and physical activity.

RESULTS

Non-LNS and LNS groups did not differ in systolic (99.2 ± 0.4 compared with 98.5 ± 0.6 mm Hg; P = 0.317) or diastolic (60.1 ± 0.3 compared with 60.0 ± 0.4 mm Hg; P = 0.805) BP, or prevalence of high BP (systolic or diastolic BP ≥90th percentile of the US National Heart, Lung, and Blood Institute reference: 31% compared with 28%; P = 0.251). BP at 4-6 y of age was positively related to birth weight; this relation was largely mediated through concurrent WAZ in a path model. Concurrent WAZ and maternal BP were the factors most strongly related to child BP.

CONCLUSIONS

Despite greater birth weight in the LNS group, there was no intervention group difference in BP at 4-6 y. In this preschool population at high risk of adult hypertension based on BP at 4-6 y, high maternal BP and child WAZ were key factors related to BP. This trial was registered at clinicaltrials.gov as NCT00970866.

High Fat Programming and Cardiovascular Disease

Programming is triggered through events during critical developmental phases that alter offspring health outcomes. High fat programming is defined as the maintenance on a high fat diet during fetal and/or early postnatal life that induces metabolic and physiological alterations that compromise health. The maternal nutritional status, including the dietary fatty acid composition, during gestation and/or lactation, are key determinants of fetal and postnatal development. A maternal high fat diet and obesity during gestation compromises the maternal metabolic state and, through high fat programming, presents an unfavorable intrauterine milieu for fetal growth and development thereby conferring adverse cardiac outcomes to offspring. Stressors on the heart, such as a maternal high fat diet and obesity, alter the expression of cardiac-specific factors that alter cardiac structure and function. The proper nutritional balance, including the fatty acid balance, particularly during developmental windows, are critical for maintaining cardiac structure, preserving cardiac function and enhancing the cardiac response to metabolic challenges.

Prenatal hypoxia impairs cardiac mitochondrial and ventricular function in guinea pig offspring in a sex-related manner

Adverse intrauterine conditions cause fetal growth restriction and increase the risk of adult cardiovascular disease. We hypothesize that intrauterine hypoxia impairs fetal heart function, is sustained after birth, and manifests as both cardiac and mitochondrial dysfunction in offspring guinea pigs (GPs). Pregnant GPs were exposed to 10.5% O₂ (HPX) at 50 days of gestation (full term = 65 days) or normoxia (NMX) for the duration of the pregnancy. Pups were allowed to deliver vaginally and raised in a NMX environment. At 90 days of age, mean arterial pressure (MAP) was measured in anesthetized GPs. NMX and prenatally HPX offspring underwent echocardiographic imaging for in vivo measurement of left ventricular cardiac morphology and function, and O₂ consumption rates and complex IV enzyme activity were measured from isolated cardiomyocytes and mitochondria, respectively. Prenatal HPX increased ( P < 0.01) MAP (52.3 ± 1.3 and 58.4 ± 1.1 mmHg in NMX and HPX, respectively) and decreased ( P < 0.05) stroke volume (439.8 ± 54.5 and 289.4 ± 15.8 μl in NMX and HPX, respectively), cardiac output (94.4 ± 11.2 and 67.3 ± 3.8 ml/min in NMX and HPX, respectively), ejection fraction, and fractional shortening in male, but not female, GPs. HPX had no effect on left ventricular wall thickness or end-diastolic volume in either sex. HPX reduced mitochondrial maximal respiration and respiratory reserve capacity and complex IV activity rates in hearts of male, but not female, GPs. Prenatal HPX is a programming stimulus that increases MAP and decreases cardiac and mitochondrial function in male offspring. Sex-related differences in the contractile and mitochondrial responses suggest that female GPs are protected from cardiovascular programming of prenatal HPX.

Maternal verbally aggressive behavior in early infancy is associated with blood pressure at age 5–6

Early life stress has been shown to contribute to alterations in biobehavioral regulation. Whereas many different forms of childhood adversities have been studied in relation to cardiovascular outcomes, very little is known about potential associations between caregivers’ verbally aggressive behavior and heart rate and blood pressure in the child. This prospective study examined whether maternal verbally aggressive behavior in early infancy is associated with heart rate or blood pressure at age 5–6. In the Amsterdam Born Children and their Development study, a large prospective, population-based birth cohort, maternal verbally aggressive behavior was assessed by questionnaire in the 13th week after birth. The child’s blood pressure and heart rate were measured during rest at age 5–6 (n=2553 included). Maternal verbally aggressive behavior in infancy was associated with a higher systolic blood pressure (SBP) both in supine and sitting position after adjustment for sex, height and age (SBP supine B=1.01 mmHg; 95% CI [0.06; 1.95] and SPB sitting B=1.29 mmHg; 95% CI [0.12; 2.46]). Adjustment for potential confounding variables, such as other mother–infant dyad aspects, family hypertension and child’s BMI, only slightly attenuated the associations (SBP supine B=0.99 mmHg; 95% CI [0.06; 1.93] and SPB sitting B=1.11 mmHg; 95% CI [−0.06; 2.27]). Maternal verbally aggressive behavior was not associated with diastolic blood pressure or heart rate at age 5–6. Maternal verbally aggressive behavior might be an important early life stressor with negative impact on blood pressure later in life, which should be further investigated. Possible underlying mechanisms are discussed.

Birthweight and cardiometabolic risk patterns in multiracial children

BACKGROUND/OBJECTIVES

Prenatal growth, which is widely marked by birthweight, may have a pivotal role in affecting the lifelong risk of cardiometabolic disorders; however, comprehensive evaluation of its relations with childhood cardiometabolic risk patterns and the ethnic and gender disparities in national representative populations is still lacking. The aim of this study was to evaluate the associations between birthweight and comprehensive patterns of cardiometabolic risk in a nationally representative sample of children and adolescents.

SUBJECTS/METHODS

Prospective analyses were performed using data from 28 153 children 0 to 15 years in the National Health and Nutrition Examination Survey from 1999 through 2014. We defined childhood cardiometabolic disorders using standard definitions for obesity, high blood pressure, hyperglycemia and dyslipidemia.

RESULTS

Five birthweight categories <2.5, 2.5-3.0, 3.0-3.5, 3.5-4.2 and ⩾4.2 kg accounted for 8.2%, 17.9%, 35.7%, 27.9% and 10.4% of the population, respectively. In all children, with increasing birthweight, we observed significantly increasing trends of the risk of general and central obesity (P for trend <0.01) and significantly decreasing trends of the risk of high systolic blood pressure (SBP), high HbA1c and low high-density lipoprotein cholesterol (HDL-C) (P for trend <0.05). The associations were independent of current body mass index (BMI). In addition, we found that the relations of birthweight with high waist circumference in Black children showed U-shape, as well as high SBP in Mexican and Hispanic children. Moreover, we found that the associations of low birthweight with high SBP and low HDL-C appeared to more prominent significant in boys, whereas the inverse association with high HbA1c was more evident in girls.

CONCLUSIONS

Our data indicate that birthweight is significantly related to childhood cardiometabolic risk, independent of current BMI, and the associations exhibit race and gender-specific patterns.

Blood Pressure in 6-Year-Old Children Born Extremely Preterm

Background

Advances in perinatal medicine have increased infant survival after very preterm birth. Although this progress is welcome, there is increasing concern that preterm birth is an emerging risk factor for hypertension at young age, with implications for the lifetime risk of cardiovascular disease.

Methods and Results

We measured casual blood pressures (BPs) in a population‐based cohort of 6‐year‐old survivors of extremely preterm birth (<27 gestational weeks; n=171) and in age‐ and sex‐matched controls born at term (n=172). Measured BP did not differ, but sex, age‐, and height‐adjusted median z scores were 0.14 SD higher (P=0.02) for systolic BP and 0.10 SD higher (P=0.01) for diastolic BP in children born extremely preterm than in controls. Among children born extremely preterm, shorter gestation, higher body mass index, and higher heart rate at follow‐up were all independently associated with higher BP at 6 years of age, whereas preeclampsia, smoking in pregnancy, neonatal morbidity, and perinatal corticosteroid therapy were not. In multivariate regression analyses, systolic BP decreased by 0.10 SD (P=0.08) and diastolic BP by 0.09 SD (P=0.02) for each week‐longer gestation.

Conclusions

Six‐year‐old children born extremely preterm have normal but slightly higher BP than their peers born at term. Although this finding is reassuring for children born preterm and their families, follow‐up at older age is warranted.

Impaired nephrogenesis in neonatal rats with oxygen-induced retinopathy

BACKGROUND

Preterm neonates are born while nephrogenesis is ongoing, and are commonly exposed to factors in a hyperoxic environment that can impair renal development. Oxidative stress has also been implicated in the development of retinopathy of prematurity (ROP). The rat model of oxygen-induced retinopathy (OIR) is the most clinically relevant model of ROP because its biologic features closely resemble those of ROP in preterm infants. We investigated impaired renal development in a rat model of OIR.

METHODS

Newborn Sprague-Dawley rats were maintained in either a normoxic (room air, 21% O₂ ; control group) or a controlled hyperoxic (80% O₂ ; OIR group) environment from birth to postnatal day (P) 12. All pups were then raised in room air from P12 to P19.

RESULTS

The hyperoxic environment led to significantly higher urinary excretion of 8-hydroxy-2'-deoxyguanosine, a marker of oxidative DNA damage, and a reduction in nephrogenic zone width at P5 in OIR pups. Additionally, glomerular count was significantly reduced by 20% in the OIR group, and avascular and neovascular changes in the retina were observed only in the OIR group at P19. Messenger RNA levels of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-β, essential angiogenic cytokines for glomerulogenesis, in the renal cortex were significantly lower at P5 and significantly higher at P19 in the OIR group compared with controls.

CONCLUSION

Renal impairment was caused by exposure to a hyperoxic environment during nephrogenesis, and the pathology of the impaired nephrogenesis in this OIR model reflects the characteristics of ROP observed in preterm infants.

Developmental Origins of Cardiometabolic Diseases: Role of the Maternal Diet

Developmental origins of cardiometabolic diseases have been related to maternal nutritional conditions. In this context, the rising incidence of arterial hypertension, diabetes type II, and dyslipidemia has been attributed to genetic programming. Besides, environmental conditions during perinatal development such as maternal undernutrition or overnutrition can program changes in the integration among physiological systems leading to cardiometabolic diseases. This phenomenon can be understood in the context of the phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental input without genetic change, following a novel, or unusual input during development. Experimental studies indicate that fetal exposure to an adverse maternal environment may alter the morphology and physiology that contribute to the development of cardiometabolic diseases. It has been shown that both maternal protein restriction and overnutrition alter the central and peripheral control of arterial pressure and metabolism. This review will address the new concepts on the maternal diet induced-cardiometabolic diseases that include the potential role of the perinatal malnutrition.

Nitric oxide synthase and changes in oxidative stress levels in embryonic kidney observed in a rabbit model of intrauterine growth restriction

OBJECTIVE

This work aimed to study the effect of uteroplacental circulation restriction on endothelial kidney damage in a fetal rabbit model.

METHODS

New Zealand rabbits were subjected to 40% to 50% of uteroplacental artery ligation at day 25 of pregnancy. After 5 days, surviving fetuses were harvested by cesarean section. The gene and protein expressions of selected enzymes associated with nitric oxide production and oxidative stress were analyzed in fetal kidney homogenates.

RESULTS

The placenta weight (6.06 ± 0.27, p < 0.0319) and fetal body (19.90 ± 1.03, p < 0.0001) were significantly reduced in the uteroplacental circulation restriction group. The kidneys from restricted fetuses presented a mild vascular congestion and glomerular capillary congestion, without inflammation or hypertrophy. We found endothelial nitric oxide synthase phosphorylation inhibition (0.23 ± 0.13, p < 0.012) and arginase-2 (0.29 ± 0.14, p < 0.023) protein induction in fetal kidneys of the circulation restriction group. Finally, the kidneys from circulation-restricted fetuses showed increased inducible nitric oxide synthase messenger RNA (mRNA) (2.68 ± 0.24, p < 0.01) and reduced heme oxygenase-1 mRNA (23 ± 1.3, p < 0.003), with increased reactive oxygen species (1.69 ± 0.09, p < 0.001) and nitrotyrosine protein (1.74 ± 0.28, p < 0.003) levels, without changes in Nox mRNA.

CONCLUSION

We describe significant deregulation of vascular activity and oxidative damage in kidneys of fetal rabbits that have been exposed to restriction of the uterine circulation. © 2016 John Wiley & Sons, Ltd.

Early growth and changes in blood pressure during adult life

Previous studies suggest that the inverse association between birth weight and adult blood pressure amplifies with age. Rapid childhood growth has also been linked to hypertension. The objective of this study was to determine whether the association between childhood growth and adult blood pressure amplifies with age. The study comprised 574 women and 462 men from the Helsinki Birth Cohort Study who attended a clinical study in 2001–2004 and a follow-up in 2006–2008. Mean age at the clinic visits was 61.5 and 66.4 years, respectively. Blood pressure was measured at both occasions. Conditional growth models were used to assess relative weight gain and linear growth. We studied the associations between conditional growth and blood pressure as well as the presence of hypertension. Relative weight gain and linear growth between ages 2 and 11 years were inversely associated with systolic blood pressure at mean age 66.4 years, after adjustment for sex, blood pressure at mean age 61.5 years, as well as other covariates. A one s.d. increase in linear growth between 2 and 11 years was associated with an OR of 0.61 for hypertension at mean age 66.4 years. Contrary to previous studies, we have shown an inverse association between childhood growth and adult blood pressure. There were, however, no associations between childhood growth and systolic blood pressure at mean age 61.5 years indicating that the beneficial effects of a more rapid than expected childhood growth might become more apparent with increasing age.

New Insights on the Maternal Diet Induced-Hypertension: Potential Role of the Phenotypic Plasticity and Sympathetic-Respiratory Overactivity

Systemic arterial hypertension (SAH) is an important risk factor for cardiovascular disease and affects worldwide population. Current environment including life style coupled with genetic programming have been attributed to the rising incidence of hypertension. Besides, environmental conditions during perinatal development such as maternal malnutrition can program changes in the integration among renal, neural, and endocrine system leading to hypertension. This phenomenon is termed phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental stimuli without genetic change, following a novel or unusual input during development. Human and animal studies indicate that fetal exposure to an adverse maternal environment may alter the renal morphology and physiology that contribute to the development of hypertension. Recently, it has been shown that the maternal protein restriction alter the central control of SAH by a mechanism that include respiratory dysfunction and enhanced sympathetic-respiratory coupling at early life, which may contribute to adult hypertension. This review will address the new insights on the maternal diet induced-hypertension that include the potential role of the phenotypic plasticity, specifically the perinatal protein malnutrition, and sympathetic-respiratory overactivity.

Maternal-pup interaction disturbances induce long-lasting changes in the newborn rat pulmonary vasculature

The factors accounting for the pathological maintenance of a high pulmonary vascular (PV) resistance postnatally remain elusive, but neonatal stressors may play a role in this process. Cross-fostering in the immediate neonatal period is associated with adult-onset vascular and behavioral changes, likely triggered by early-in-life stressors. In hypothesizing that fostering newborn rats induces long-lasting PV changes, we evaluated them at 14 days of age during adulthood and compared the findings with animals raised by their biological mothers. Fostering resulted in reduced maternal-pup contact time when compared with control newborns. At 2 wk of age, fostered rats exhibited reduced pulmonary arterial endothelium-dependent relaxation secondary to downregulation of tissue endothelial nitric oxide synthase expression and tetrahydrobiopterin deficiency-induced uncoupling. These changes were associated with neonatal onset-increased ANG II receptor type 1 expression, PV remodeling, and right ventricular hypertrophy that persisted into adulthood. The pulmonary arteries of adult-fostered rats exhibited a higher contraction dose response to ANG II and thromboxane A2, the latter of which was abrogated by the oxidant scavenger Tempol. In conclusion, fostering-induced neonatal stress induces long-standing PV changes modulated via the renin-angiotensin system.

A new serum cystatin C formula for estimating glomerular filtration rate in newborns

BACKGROUND

The levels of serum cystatin C (CysC) and creatinine (Cr) were determined in small-for-gestational-age (SGA) babies and compared with those for normal term newborns appropriate for gestational age (AGA), at birth and 3 days later. We then compared a number of cysC-based, Cr-based and combined formulas for estimation of glomerular filtration rate (GFR) with the neonatal reference GFR.

METHODS

Fifty full-term SGA and 50 AGA newborns were enrolled in the study. Kidney volume measurements were performed by ultrasound for each newborn.

RESULTS

At birth, the mean level of CysC in SGA babies was 1.48 ± 0.30 mg/l in cord blood and 1.38 ± 0.18 mg/l in day 3 blood samples, and the mean Cr level, determined simultaneously, was 67.08 ± 17.62 and 55.62 ± 14.91 μmol/l, respectively. These levels did not differ significantly from those determined in AGA babies. A 10 % reduction in kidney volume was associated with an increase in CysC value of 9.3 % in cord blood. The Cr-based and Schwartz-combined equations underestimated GFR relative to CysC-based and Zappitelli-based equations at birth and 3 days later.

CONCLUSIONS

A newly constructed Cys-C based formula which includes kidney volume and body surface area in the calculations for GFR is a reliable marker of GFR compared with neonatal reference clearance values.

Neural programming of mesenteric and renal arteries

There is evidence for developmental origins of vascular dysfunction yet little understanding of maturation of vascular smooth muscle (VSM) of regional circulations. We measured maturational changes in expression of myosin phosphatase (MP) and the broader VSM gene program in relation to mesenteric small resistance artery (SRA) function. We then tested the role of the sympathetic nervous system (SNS) in programming of SRAs and used genetically engineered mice to define the role of MP isoforms in the functional maturation of the mesenteric circulation. Maturation of rat mesenteric SRAs as measured by qPCR and immunoblotting begins after the second postnatal week and is not complete until maturity. It is characterized by induction of markers of VSM differentiation (smMHC, γ-, α-actin), CPI-17, an inhibitory subunit of MP and a key target of α-adrenergic vasoconstriction, α1-adrenergic, purinergic X1, and neuropeptide Y1 receptors of sympathetic signaling. Functional correlates include maturational increases in α-adrenergic-mediated force and calcium sensitization of force production (MP inhibition) measured in first-order mesenteric arteries ex vivo. The MP regulatory subunit Mypt1 E24+/LZ- isoform is specifically upregulated in SRAs during maturation. Conditional deletion of mouse Mypt1 E24 demonstrates that splicing of E24 causes the maturational reduction in sensitivity to cGMP-mediated vasorelaxation (MP activation). Neonatal chemical sympathectomy (6-hydroxydopamine) suppresses maturation of SRAs with minimal effect on a conduit artery. Mechanical denervation of the mature rat renal artery causes a reversion to the immature gene program. We conclude that the SNS captures control of the mesenteric circulation by programming maturation of the SRA smooth muscle.

Factors associated with a vicious cycle involving a low nephron number, hypertension and chronic kidney disease

It has been reported that there is substantial variation in the nephron number between individuals. Previous studies using autopsy kidneys have demonstrated that a low nephron number, in relation to a low birth weight, may result in hypertension (HTN) and/or chronic kidney disease (CKD). However, recent studies have revealed that the association between a low nephron number and HTN is not a universal finding. This observation indicates that a low nephron number is unlikely to be the sole factor contributing to an elevated blood pressure. In addition to the nephron number, various genetic and congenital factors may contribute to increased susceptibility to HTN and/or CKD in a complex manner. Acquired factors, including aging, obesity and related metabolic abnormalities, and various causes of renal injury, may additionally promote further nephron loss. Such a vicious cycle may induce HTN and/or CKD via the common mechanisms of renal hemodynamic maladaptation.

Mechanisms involved in developmental programming of hypertension and renal diseases. Gender differences

BACKGROUND

A substantial body of epidemiological and experimental evidence suggests that a poor fetal and neonatal environment may "program" susceptibility in the offspring to later development of cardiovascular, renal and metabolic diseases.

MATERIALS AND METHODS

This review focuses on current knowledge from the available literature regarding the mechanisms linking an adverse developmental environment with an increased risk for cardiovascular, renal and metabolic diseases in adult life. Moreover, this review highlights important sex-dependent differences in the adaptation to developmental insults.

RESULTS

Developmental programming of several diseases is secondary to changes in different mechanisms inducing important alterations in the normal development of several organs that lead to significant changes in birth weight. The different diseases occurring as a consequence of an adverse environment during development are secondary to morphological and functional cardiovascular and renal changes, to epigenetic changes and to an activation of several hormonal and regulatory systems, such as angiotensin II, sympathetic activity, nitric oxide, COX2-derived metabolites, oxidative stress and inflammation. The important sex-dependent differences in the developmental programming of diseases seem to be partly secondary to the effects of sex hormones. Recent studies have shown that the progression of these diseases is accelerated during aging in both sexes.

CONCLUSIONS

The cardiovascular, renal and metabolic diseases during adult life that occur as a consequence of several insults during fetal and postnatal periods are secondary to multiple structural and functional changes. Future studies are needed in order to prevent the origin and reduce the incidence and consequences of developmental programmed diseases.

Lower Protein-to-Carbohydrate Ratio in Maternal Diet is Associated with Higher Childhood Systolic Blood Pressure up to Age Four Years

The prenatal environment can influence development of offspring blood pressure (BP), which tracks into adulthood. This prospective longitudinal study investigated whether maternal pregnancy dietary intake is associated with the development of child BP up to age four years. Data are from 129 mother-child dyads enrolled in the Women and Their Children's Health study. Maternal diet was assessed using a validated 74-item food frequency questionnaire at 18 to 24 weeks and 36 to 40 weeks, with a reference period of the previous three months. Child systolic and diastolic BP were measured at 3, 6, 9, 12, 24, 36 and 48 months, using an automated BP monitor. Using mixed-model regression analyses adjusted for childhood growth indices, pregnancy intakes of percentage of energy (E%) polyunsaturated fat (β coefficient 0.73; 95% CI 0.003, 1.45; p = 0.045), E% omega-6 fatty acids (β coefficient 0.89; 95% CI 0.09, 1.69; p = 0.03) and protein-to-carbohydrate (P:C) ratio (β coefficient -14.14; 95% CI -27.68, -0.60; p = 0.04) were associated with child systolic BP trajectory up to 4 years. Child systolic BP was greatest at low proportions of dietary protein (<16% of energy) and high carbohydrate (>40% of energy) intakes. There may be an ideal maternal macronutrient ratio associated with optimal infant BP. Maternal diet, which is potentially modifiable, may play an important role in influencing offspring risk of future hypertension.

Fetal kidney programming by maternal smoking exposure: effects on kidney structure, blood pressure and urinary sodium excretion in adult offspring

INTRODUCTION

Fetal programming by different insults results in low birth weight and reduction in nephron number increasing the risk for adult development of cardiovascular and renal diseases. Maternal smoking is an important modifiable adverse fetal exposure worldwide and leads to a decrease in the offspring's birth weight. Thus far, the specific adverse fetal smoking exposures and mechanisms underlying these associations on renal development and functional disorder are unclear.

METHODS

The present study investigates, in adult male rats, the effect of smoking exposure (Sk) in uteri on blood pressure (BP) by an indirect tail-cuff method using an electrosphygmomanometer, and its association with nephron structure by stereological estimation, immunohistochemical and histological techniques, in parallel with kidney function creatinine and lithium clearance.

RESULTS

The current study showed in a 16-week old Sk offspring enhanced arterial blood pressure associated with, reduced urinary sodium excretion and higher TGF-β1 glomerular expression. Sk glomeruli also presented an upregulated collagen and fibronectin deposition intrinsically related to fibrotic process as compared to age-matched control group.

CONCLUSION

Here, we demonstrate that fetal-programmed Sk offspring present pronounced glomerular TGF-β1 and fibrotic marker expression that may, subsequently, promote a glomerular epithelial-mesenchymal transition activated process in an Sk offspring. Although the precise mechanism responsible for the subsequently renal morphological and functional response in Sk offspring is incompletely known, the current data suggest that changes in renal function are conducive to excess sodium tubule reabsorption that is associated with enhanced TGF-β1, fibronectin and collagen deposition, intrinsically related to fibrotic process, might potentiate the programming of adult hypertension.