Endothelial function is impaired in fit young adults of low birth weight

Reconsidering the developmental origins of adult disease paradigm: The 'metabolic coordination of childbirth' hypothesis

In uncomplicated pregnancies, birthweight is inversely associated with adult non-communicable disease (NCD) risk. One proposed mechanism is maternal malnutrition during pregnancy. Another explanation is that shared genes link birthweight with NCDs. Both hypotheses are supported, but evolutionary perspectives address only the environmental pathway. We propose that genetic and environmental associations of birthweight with NCD risk reflect coordinated regulatory systems between mother and foetus, that evolved to reduce risks of obstructed labour. First, the foetus must tailor its growth to maternal metabolic signals, as it cannot predict the size of the birth canal from its own genome. Second, we predict that maternal alleles that promote placental nutrient supply have been selected to constrain foetal growth and gestation length when fetally expressed. Conversely, maternal alleles that increase birth canal size have been selected to promote foetal growth and gestation when fetally expressed. Evidence supports these hypotheses. These regulatory mechanisms may have undergone powerful selection as hominin neonates evolved larger size and encephalisation, since every mother is at risk of gestating a baby excessively for her pelvis. Our perspective can explain the inverse association of birthweight with NCD risk across most of the birthweight range: any constraint of birthweight, through plastic or genetic mechanisms, may reduce the capacity for homeostasis and increase NCD susceptibility. However, maternal obesity and diabetes can overwhelm this coordination system, challenging vaginal delivery while increasing offspring NCD risk. We argue that selection on viable vaginal delivery played an over-arching role in shaping the association of birthweight with NCD risk.

Cardiovascular Dysfunction in Intrauterine Growth Restriction

PURPOSE OF REVIEW

We highlight important new findings on cardiovascular dysfunction in intrauterine growth restriction.

RECENT FINDINGS

Intrauterine growth restriction (IUGR) is a multifactorial condition which negatively impacts neonatal growth during pregnancy and is associated with health problems during the lifespan. It affects 5-15% of all pregnancies in the USA and Europe with varying percentages in developing countries. Epidemiological studies have reported that IUGR is associated with the pathogenesis of hypertension, activation of the renin-angiotensin system (RAS), disruption in placental-mTORC and TGFβ signaling cascades, and endothelial dysfunction in IUGR fetuses, children, adolescents, and adults resulting in the development of cardiovascular diseases (CVD). Experimental studies are needed to investigate therapeutic measures to treat increased blood pressure (BP) and long-term CVD problems in people affected by IUGR. We outline the mechanisms mediating fetal programming of hypertension in developing CVD. We have reviewed findings from different experimental models focusing on recent studies that demonstrate CVD in IUGR.

Altered cerebrovascular regulation in low birthweight swine

Full-term low birthweight (LBW) offspring exhibit peripheral vascular dysfunction in the postnatal period; however, whether such impairments extend to the cerebrovasculature remains to be elucidated. We used a swine model to test the hypothesis that LBW offspring would exhibit cerebrovascular dysfunction at later stages of life. Offspring from 14 sows were identified as normal birthweight (NBW) or LBW and were assessed at 28 (similar to end of infancy) and 56 (similar to childhood) days of age. LBW swine had lower absolute brain mass, but demonstrated evidence of brain sparing (increased brain mass scaled to body mass) at 56 days of age. The cerebral pulsatility index, based on transcranial Doppler, was increased in LBW swine. Moreover, arterial myography of isolated cerebral arteries revealed impaired vasoreactivity to bradykinin and reduced contribution of nitric oxide (NO) to vasorelaxation in the LBW swine. Immunoblotting demonstrated a lower ratio of phosphorylated-to-total endothelial NO synthase in LBW offspring. This impairment in NO signaling was greater at 28 vs. 56 days of age. Vasomotor responses to sodium nitroprusside (NO-donor) were unaltered, while Leu³¹, Pro³⁴ neuropeptide Y-induced vasoconstriction was enhanced in LBW swine. Increases in total Y1 receptor protein content in the LBW group were not significant. In summary, LBW offspring displayed signs of cerebrovascular dysfunction at 28 and 56 days of age, evidenced by altered cerebral hemodynamics (reflective of increased impedance) coupled with endothelial dysfunction and altered vasomotor control. Overall, the data reveal that normal variance in birthweight of full-term offspring can influence cerebrovascular function later in life.

Evaluation of Fetal Renal Artery Doppler Indices in Pregnancies Complicated with Preeclampsia

OBJECTIVE

Preeclampsia, characterized by endothelial dysfunction, is associated with maternal and fetal Doppler alterations. This study aimed to evaluate fetal renal artery Doppler indices in pregnancies complicated with preeclampsia and compare them with normotensive pregnancies.

DESIGN

This cross-sectional study enrolled 46 pregnancies complicated with preeclampsia between weeks 24 and 37 of gestation as the study group and 48 normotensive pregnancies as the control group.

MATERIALS AND METHODS

The abdominal aorta, its bifurcation, and the renal arteries were visualized in the coronal view of the fetal abdomen using color Doppler. Renal artery Doppler indices were measured after arising from the abdominal aorta. The angle of insonation was ≤30° from the direction of blood flow, and the sample volume was 2 mm. Fetal renal artery pulsatility index, resistance index, systolic/diastolic ratio, and peak systolic velocity (PSV) were measured. All Doppler measurements were performed in the absence of fetal movements. Moreover, demographic characteristics and the perinatal outcome data of patients were recorded.

RESULTS

The values of fetal renal artery pulsatility and resistance indices were found to be significantly lower in the study group than those in the control group (p < 0.001 and p = 0.013, respectively). The fetal renal artery systolic/diastolic ratio and PSV values were also significantly lower in the study group compared with those in the control group (p = 0.007 and p < 0.001, respectively). Renal artery pulsatility and resistance indices were negatively correlated with mean arterial pressure (r = -0.381, p < 0.001 and r = -0.267, p = 0.009, respectively). The renal artery systolic/diastolic ratio was also significantly negatively correlated with the mean arterial pressure (r = -0.257, p = 0.013).

LIMITATIONS

The main limitations of this study are its cross-sectional design and the small number of participants. Another limitation of the study is that preeclamptic pregnancies complicated with fetal growth restriction were not included.

CONCLUSION

The observed decrease in fetal renal artery Doppler impedance may be caused by the unique response of the fetal renal artery to the factors involved in the etiopathogenesis of preeclampsia than other fetal peripheral vessels. These changes in fetal renal artery indices in pregnancies complicated with preeclampsia could be taken into account in the assessment of fetal health.

Cardiovascular and Cerebrovascular Implications of Growth Restriction: Mechanisms and Potential Treatments

Fetal growth restriction (FGR) is a common complication of pregnancy, resulting in a fetus that fails to reach its genetically determined growth potential. Whilst the fetal cardiovascular response to acute hypoxia is well established, the fetal defence to chronic hypoxia is not well understood due to experiment constraints. Growth restriction results primarily from reduced oxygen and nutrient supply to the developing fetus, resulting in chronic hypoxia. The fetus adapts to chronic hypoxia by redistributing cardiac output via brain sparing in an attempt to preserve function in the developing brain. This review highlights the impact of brain sparing on the developing fetal cardiovascular and cerebrovascular systems, as well as emerging long-term effects in offspring that were growth restricted at birth. Here, we explore the pathogenesis associated with brain sparing within the cerebrovascular system. An increased understanding of the mechanistic pathways will be critical to preventing neuropathological outcomes, including motor dysfunction such as cerebral palsy, or behaviour dysfunctions including autism and attention-deficit/hyperactivity disorder (ADHD).

Premature birth, low birth weight, small for gestational age and chronic non-communicable diseases in adult life: A systematic review with meta-analysis

BACKGROUND

Individuals who were born prematurely (PT), with low birth weight (LBW), or small for gestational age (SGA) appear to present a set of permanent changes that make them more susceptible to develop chronic non-communicable diseases (CNCD) in adult life.

AIM

Investigating the association between PT birth, LBW or SGA at birth and CNCD incidence in adult life.

METHODS

Systematic review with meta-analysis of studies available in three databases - two of them are official (PubMed and Web of Science) and one is gray literature (OpenGrey) - based on pre-established search and eligibility criteria.

RESULTS

Sixty-four studies were included in the review, 93.7% of them only investigated one of the exposure variables (46.7% LBW, 35.0% PT and 18.3% SGA at birth), whereas 6.3% investigated more than one exposure variable (50.0% LBW and PT; 50.0% SGA and PT). There was association among all exposure variables in the following outcomes: cardiometabolic (CMD) and glycidic metabolism (GMD) disorders, changes in body composition and risk of developing metabolic syndrome (MS). Female sex was identified as risk factor in the exposure-outcome association. Eighteen (18) articles were included in the meta-analysis. There was positive association between LBW and incidence of CMD (OR: 1.25 [95%CI: 1.11; 1.41]; 07 studies), GMD (OR: 1.70 [95%CI: 1.25; 2.30]; 03 studies) and MS (OR: 1.75 [95%CI: 1.27; 2.40]; 02 studies) in adult life. PT was positively associated with CMD (OR: 1.38 [95%CI: 1.27; 1.51]; 05 studies).

CONCLUSIONS

LBW and PT are associated with CMD and GMD development, as well as with the risk of developing MS in adult life.

Low birth weight trends: possible impacts on the prevalences of hypertension and chronic kidney disease

Worldwide, hypertension and chronic kidney disease (CKD) are highly prevalent disorders and are strong risk factors for cardiovascular disease and end-stage renal disease (ESRD). The developmental origins of health and disease (DOHAD) concept suggests that undesirable perinatal environmental conditions, such as malnutrition, contribute to disease development in adults. Among the known hypertension and CKD risk factors, DOHAD plays a potential role in determining susceptibility to the onset of these diseases in later adulthood. Since low birth weight (LBW) is a surrogate marker for adverse fetal environmental conditions, the high incidence of LBW in developing countries and its increasing incidence in most developed countries (attributed to multiple pregnancies and prepregnancy maternal factors, such as undernutrition, advanced maternal age, and smoking) is concerning. Thus, LBW is an important public health problem not only because of the associated infant mortality and morbidity but also because it is a risk factor for adult-onset hypertension/CKD. During their reproductive years, pregnant women who were born with LBWs have an increased risk of hypertensive disorders of pregnancy, which contribute to the risk of developing cardiovascular disease and ESRD. The offspring of LBW females are also likely to be LBW, which suggests that susceptibility to hypertension/CKD may reflect transgenerational inheritance. Therefore, there is global concern about the increasing prevalence of LBW-related diseases. This review summarizes the relevance of hypertension and CKD in conjunction with DOHAD and discusses recent studies that have examined the impact of the upward LBW trend on renal function and blood pressure.

Early famine exposure and adult disease risk based on a 10-year prospective study of Chinese adults

OBJECTIVE

To comprehensively examine the potential impacts of prenatal experience of the Chinese Great Famine on chronic disease risks in the middle age.

METHODS

This study included 92 284 participants aged 39-51 years from China Kadoorie Biobank born around the famine period and without major chronic diseases at baseline. We categorised participants into non-famine births (born between 1 October 1956 and 30 September 1958, and 1 October 1962 and 30 September 1964) and famine births (born between 1 October 1959 and 30 September 1961). The outcomes were incident cardiovascular disease, cancer and respiratory system disease. Cox regression was used to estimate adjusted HR and 95% CI for famine exposure. Subgroup analyses were performed according to baseline characteristics.

RESULTS

During a median 10.1 years of follow-up, we identified 4626 incident ischaemic heart disease (IHD) cases, 7332 cerebrovascular disease cases, 3111 cancer cases and 16 081 respiratory system disease cases. In the whole population, prenatal famine exposure was not statistically associated with the risks of developing any chronic diseases in adulthood. However, for urban participants, compared with non-famine births, famine births had a higher risk of cerebrovascular disease (HR 1.18; 95% CI 1.09 to 1.28); such association was not shown for rural participants (p for interaction <0.001). Also, we observed the associations of prenatal famine exposure with IHD (HR 1.15; 95% CI 1.05 to 1.26) and cerebrovascular disease (HR 1.13; 95% CI 1.05 to 1.21) in participants with lower physical activity level, but not in those with higher ones (all p for interaction=0.003).

CONCLUSION

Our findings indicate that prenatal exposure to the Chinese famine might be associated with an increased cardiovascular risk and such risk may be modified by adult lifestyle.

Intrauterine growth restriction results in persistent vascular mismatch in adulthood

KEY POINTS

Intrauterine growth restriction (IUGR) increases offspring risk of chronic diseases later in life, including cardiovascular dysfunction. Our prior studies suggest biventricular cardiac dysfunction and vascular impairment in baboons who were IUGR at birth because of moderate maternal nutrient reduction. The current study reveals changes in artery sizes, distensibility, and blood flow pattern in young adult IUGR baboons, which may contribute to cardiac stress. The pattern of abnormality observed suggests that vascular redistribution seen with IUGR in fetal life may continue into adulthood.

ABSTRACT

Maternal nutrient reduction induces intrauterine growth restriction (IUGR), increasing risks of chronic diseases later in life, including cardiovascular dysfunction. Using ultrasound, we determined regional blood flow, blood vessel sizes, and distensibility in IUGR baboons (8 males, 8 females, 8.8 years, similar to 35 human years) and controls (12 males, 12 females, 9.5 years). The measured blood vessels were larger in size in the males compared to females before but not after normalization to body surface area. Smaller IUGR normalized blood vessel sizes were observed in the femoral and external iliac arteries but not the brachial or common carotid arteries and not correlated significantly with birth weight. Mild decrease in distensibility in the IUGR group was seen in the iliac but not the carotid arteries without between-sex differences. In IUGR baboons there was increased carotid arterial blood flow velocity during late systole and diastole. Overall, our findings support the conclusion that region specific vascular and haemodynamic changes occur with IUGR, which may contribute to the occurrence of later life cardiac dysfunction. The pattern of alteration observed suggests vascular redistribution efforts in response to challenges in the perinatal period may persist into adulthood. Further studies are needed to determine the life course progression of these changes.

The effect of intrauterine growth restriction on Ca2+ -activated force and contractile protein expression in the mesenteric artery of adult (6-month-old) male and female Wistar-Kyoto rats

Intrauterine growth restriction (IUGR) is known to alter vascular smooth muscle reactivity, but it is currently unknown whether these changes are driven by downstream events that lead to force development, specifically, Ca2+ -regulated activation of the contractile apparatus or a shift in contractile protein content. This study investigated the effects of IUGR on Ca2+ -activated force production, contractile protein expression, and a potential phenotypic switch in the resistance mesenteric artery of both male and female Wistar-Kyoto (WKY) rats following two different growth restriction models. Pregnant female WKY rats were randomly assigned to either a control (C; N = 9) or food restriction diet (FR; 40% of control; N = 11) at gestational day-15 or underwent a bilateral uterine vessel ligation surgery restriction (SR; N = 10) or a sham surgery control model (SC; N = 12) on day-18 of gestation. At 6-months of age, vascular responsiveness of intact mesenteric arteries was studied, before chemically permeabilization using 50 μmol/L β-escin to investigate Ca2+ -activated force. Peak responsiveness to a K+ -induced depolarization was decreased (P ≤ 0.05) due to a reduction in maximum Ca2+ -activated force (P ≤ 0.05) in both male growth restricted experimental groups. Vascular responsiveness was unchanged between female experimental groups. Segments of mesenteric artery were analyzed using Western blotting revealed IUGR reduced the relative abundance of important receptor and contractile proteins in male growth restricted rats (P ≤ 0.05), suggesting a potential phenotypic switch, whilst no changes were observed in females. Results from this study suggest that IUGR alters the mesenteric artery reactivity due to a decrease in maximum Ca2+ -activated force, and likely contributed to by a reduction in contractile protein and receptor/channel content in 6-month-old male rats, while female WKY rats appear to be protected.

High-fat diet reduces weight gain but increases other cardio-metabolic indices in offspring of normotensive and hypertensive rats

This study investigated the effect of post-natal consumption of high-fat diet (HFD) on cardio-metabolic indices in male offspring of hypertensive female rats. There were neither significant differences in body weight gain either in pups from normotensive or hypertensive dams that received normal diet during the post-weaning periods (except at 7th and 9th weeks), nor in both pup groups that received HFD. However, both pup groups that received HFD had reduced body weight gain when compared to their counterparts that received normal diet. Post-weaning administration of HFD to pups of hypertensive and normotensive dams significantly increased their blood glucose, pressure and lipid profiles when compared to those weaned to normal diet. It was concluded that male offspring consumption of HFD diet elicits cardio-metabolic disturbance that slightly depended of maternal cardiovascular status but majorly depended on post-weaning weight gain, while that elicited by maternal hypertension is not related to post-weaning weight gain.

Intrauterine growth-restricted Yucatan miniature pigs experience early catch-up growth, leading to greater adiposity and impaired lipid metabolism as young adults

Early nutrition has critical influences on cardiovascular disease risk in adulthood. The study objectives were to evaluate the impact of low birth weight on fasting and postprandial lipid metabolism and endothelium function in Yucatan miniature pigs. Intrauterine growth-restricted (IUGR) piglets (n = 6; 3 days old, 0.73 ± 0.04 kg) were paired with normal-weight (NW) same-sex littermates (n = 6; 1.11 ± 0.05 kg) and fed milk replacer ad libitum for 4 weeks. Thereafter, all pigs were fed a standard diet ad libitum for 5 h/day with growth, intakes, and blood samples collected for 8 months. At 9 months old, pigs were surgically fitted with venous catheters and an oral fat tolerance test was performed. At 10 months old, pigs were killed and endothelium-dependent and -independent vasodilations of isolated coronary arteries were measured using wire-myographs. IUGR pigs demonstrated catch-up growth (P < 0.05) in body weight and abdominal circumference prior to sexual maturity (<7 months old) and had more (P < 0.05) subcutaneous fat at 10 months old compared with NW pigs. IUGR pigs had consistently higher fasting plasma triglyceride concentrations from 5 to 10 months old and higher liver triglyceride and total cholesterol concentrations at 10 months old (P < 0.05). The fat tolerance test revealed delayed postprandial triglyceride clearance in IUGR pigs, but no differences in plaque formation or vascular reactivity. To conclude, IUGR and early postnatal catch-up growth are associated with increased overall body fat deposition and altered triglyceride metabolism in adult Yucatan miniature swine.

The highs and lows of programmed cardiovascular disease by developmental hypoxia: studies in the chicken embryo

It is now established that adverse conditions during pregnancy can trigger a fetal origin of cardiovascular dysfunction and/or increase the risk of heart disease in later life. Suboptimal environmental conditions during early life that may promote the development of cardiovascular dysfunction in the offspring include alterations in fetal oxygenation and nutrition as well as fetal exposure to stress hormones, such as glucocorticoids. There has been growing interest in identifying the partial contributions of each of these stressors to programming of cardiovascular dysfunction. However, in humans and in many animal models this is difficult, as the challenges cannot be disentangled. By using the chicken embryo as an animal model, science has been able to circumvent a number of problems. In contrast to mammals, in the chicken embryo the effects on the developing cardiovascular system of changes in oxygenation, nutrition or stress hormones can be isolated and determined directly, independent of changes in the maternal or placental physiology. In this review, we summarise studies that have exploited the chicken embryo model to determine the effects on prenatal growth, cardiovascular development and pituitary-adrenal function of isolated chronic developmental hypoxia.

Endothelial dysfunction in individuals born after fetal growth restriction: cardiovascular and renal consequences and preventive approaches

Individuals born after intrauterine growth restriction (IUGR) have an increased risk of perinatal morbidity/mortality, and those who survive face long-term consequences such as cardiovascular-related diseases, including systemic hypertension, atherosclerosis, coronary heart disease and chronic kidney disease. In addition to the demonstrated long-term effects of decreased nephron endowment and hyperactivity of the hypothalamic-pituitary-adrenal axis, individuals born after IUGR also exhibit early alterations in vascular structure and function, which have been identified as key factors of the development of cardiovascular-related diseases. The endothelium plays a major role in maintaining vascular function and homeostasis. Therefore, it is not surprising that impaired endothelial function can lead to the long-term development of vascular-related diseases. Endothelial dysfunction, particularly impaired endothelium-dependent vasodilation and vascular remodeling, involves decreased nitric oxide (NO) bioavailability, impaired endothelial NO synthase functionality, increased oxidative stress, endothelial progenitor cells dysfunction and accelerated vascular senescence. Preventive approaches such as breastfeeding, supplementation with folate, vitamins, antioxidants, L-citrulline, L-arginine and treatment with NO modulators represent promising strategies for improving endothelial function, mitigating long-term outcomes and possibly preventing IUGR of vascular origin. Moreover, the identification of early biomarkers of endothelial dysfunction, especially epigenetic biomarkers, could allow early screening and follow-up of individuals at risk of developing cardiovascular and renal diseases, thus contributing to the development of preventive and therapeutic strategies to avert the long-term effects of endothelial dysfunction in infants born after IUGR.

Pregnancy as a critical window for blood pressure regulation in mother and child: programming and reprogramming

Pregnancy is a critical time for long-term blood pressure regulation in both mother and child. Pregnancies complicated by placental insufficiency, resulting in pre-eclampsia and intrauterine growth restriction, are associated with a threefold increased risk of the mother to develop hypertension later in life. In addition, these complications create an adverse intrauterine environment, which programmes the foetus and the second generation to develop hypertension in adult life. Female offspring born to a pregnancy complicated by placental insufficiency are at risk for pregnancy complications during their own pregnancies as well, resulting in a vicious circle with programmed risk for hypertension passing from generation to generation. Here, we review the epidemiology and mechanisms leading to the altered programming of blood pressure trajectories after pregnancies complicated by placental insufficiency. Although the underlying mechanisms leading to hypertension remain the subject of investigation, several abnormalities in angiotensin sensitivity, sodium handling, sympathetic activity, endothelial function and metabolic pathways are found in the mother after exposure to placental insufficiency. In the child, epigenetic modifications and disrupted organ development play a crucial role in programming of hypertension. We emphasize that pregnancy can be viewed as a window of opportunity to improve long-term cardiovascular health of both mother and child, and outline potential gains expected of improved preconceptional, perinatal and post-natal care to reduce the development of hypertension and the burden of cardiovascular disease later in life. Perinatal therapies aimed at reprogramming hypertension are a promising strategy to break the vicious circle of intergenerational programming of hypertension.

Body composition and the monitoring of non-communicable chronic disease risk

There is a need for simple proxies of health status, in order to improve monitoring of chronic disease risk within and between populations, and to assess the efficacy of public health interventions as well as clinical management. This review discusses how, building on recent research findings, body composition outcomes may contribute to this effort. Traditionally, body mass index has been widely used as the primary index of nutritional status in children and adults, but it has several limitations. We propose that combining information on two generic traits, indexing both the ‘metabolic load’ that increases chronic non-communicable disease risk, and the homeostatic ‘metabolic capacity’ that protects against these diseases, offers a new opportunity to improve assessment of disease risk. Importantly, this approach may improve the ability to take into account ethnic variability in chronic disease risk. This approach could be applied using simple measurements readily carried out in the home or community, making it ideal for M-health and E-health monitoring strategies.

Gender differences in developmental programming of cardiovascular diseases

Hypertension is a risk factor for cardiovascular disease, the leading cause of death worldwide. Although multiple factors contribute to the pathogenesis of hypertension, studies by Dr David Barker reporting an inverse relationship between birth weight and blood pressure led to the hypothesis that slow growth during fetal life increased blood pressure and the risk for cardiovascular disease in later life. It is now recognized that growth during infancy and childhood, in addition to exposure to adverse influences during fetal life, contributes to the developmental programming of increased cardiovascular risk. Numerous epidemiological studies support the link between influences during early life and later cardiovascular health; experimental models provide proof of principle and indicate that numerous mechanisms contribute to the developmental origins of chronic disease. Sex has an impact on the severity of cardiovascular risk in experimental models of developmental insult. Yet, few studies examine the influence of sex on blood pressure and cardiovascular health in low-birth weight men and women. Fewer still assess the impact of ageing on sex differences in programmed cardiovascular risk. Thus, the aim of the present review is to highlight current data about sex differences in the developmental programming of blood pressure and cardiovascular disease.

Association between anthropometry, cardiometabolic risk factors, & early life factors & adult measures of endothelial function: Results from the New Delhi Birth Cohort

Background & objectives:

Abnormal endothelial function represents a preclinical marker of atherosclerosis. This study was conducted to evaluate associations between anthropometry, cardiometabolic risk factors, and early life factors and adult measures of endothelial function in a young urban Indian cohort free of clinical cardiovascular disease.

Methods:

Absolute changes in brachial artery diameter following cuff inflation and sublingual nitroglycerin (400 µg) were recorded to evaluate endothelium-dependent and -independent measures of endothelial function in 600 participants (362 men; 238 women) from the New Delhi Birth Cohort (2006-2009). Data on anthropometry, cardiometabolic risk factors, medical history, socio-economic position, and lifestyle habits were collected. Height and weight were recorded at birth, two and 11 yr of age. Age- and sex-adjusted linear regression models were developed to evaluate these associations.

Results:

The mean age of participants was 36±1 yr. Twenty two per cent men and 29 per cent women were obese (BMI > 30 kg/m²). Mean systolic blood pressure (SBP) was 131±14 and 119±13 mmHg, and diabetes prevalence was 12 and 8 per cent for men and women, respectively. Brachial artery diameter was higher for men compared with women both before (3.48±0.37 and 2.95±0.35 cm) and after hyperaemia (3.87±0.37 vs. 3.37±0.35 cm). A similar difference was seen before and after nitroglycerin. Markers of increased adiposity, smoking, SBP, and metabolic syndrome, but not early life anthropometry, were inversely associated with endothelial function after adjustment for age and sex.

Interpretation & conclusions:

The analysis of the current prospective data from a young urban Indian cohort showed that cardiometabolic risk factors, but not early life anthropometry, were associated with worse endothelial function.

Familial Factors, Low Birth Weight, and Development of ESRD: A Nationwide Registry Study

BACKGROUND

Previous studies have demonstrated that low birth weight (LBW) is associated with higher risk for end-stage renal disease (ESRD). However, both LBW and ESRD cluster in families. The present study investigates whether familial factors explain the association between LBW and ESRD.

STUDY DESIGN

Retrospective registry-based cohort study.

SETTING & PARTICIPANTS

Since 1967, the Medical Birth Registry of Norway has recorded medical data for all births in the country. Sibling data are available through the Norwegian Population Registry. Since 1980, all patients with ESRD in Norway have been registered in the Norwegian Renal Registry. Individuals registered in the Medical Birth Registry with at least 1 registered sibling were included.

PREDICTOR

LBW in the participant and/or LBW in at least 1 sibling.

OUTCOME

ESRD.

RESULTS

Of 1,852,080 included individuals, 527 developed ESRD. Compared with individuals without LBW and with no siblings with LBW, individuals without LBW but with a sibling with LBW had an HR for ESRD of 1.20 (95% CI, 0.91-1.59), individuals with LBW but no siblings with LBW had an HR of 1.59 (95% CI, 1.18-2.14), and individuals with LBW and a sibling with LBW had an HR of 1.78 (95% CI, 1.26-2.53). Similar results were observed for individuals who were small for gestational age (SGA). Separate analyses for the association of age 18 to 42 years and noncongenital ESRD showed stronger associations for SGA than for LBW, and the associations were not statistically significant for age 18 to 42 years for LBW.

LIMITATIONS

Follow-up only until 42 years of age.

CONCLUSIONS

LBW and SGA are associated with higher risk for ESRD during the first 40 years of life, and the associations were not explained by familial factors. Our results support the hypothesis that impaired intrauterine nephron development may be a causal risk factor for progressive kidney disease.

Impact of oxidative stress during pregnancy on fetal epigenetic patterns and early origin of vascular diseases

Epidemiological studies have led scientists to postulate the developmental origins of health and disease hypothesis for noncommunicable diseases such as diabetes, cardiovascular diseases, hypertension, and obesity. However, the cellular and molecular mechanisms involved in the development of these diseases are not well understood. In various animal models, it has been observed that oxidative stress during pregnancy is associated with the early development of endothelial dysfunction in offspring. This phenomenon suggests that endothelial dysfunction may initiate in the uterus and could lead to increased risk of cardiovascular disease later in life. Currently, it is known that many of the fetal adaptive responses to environmental factors are mediated by epigenetic changes in the genome, especially by the degree of methylation in cytosines in the promoter regions of genes. These findings suggest that the establishment of a particular epigenetic pattern in the genome may be generated by oxidative stress.

Late gestational hypoxia and a postnatal high salt diet programs endothelial dysfunction and arterial stiffness in adult mouse offspring

Gestational hypoxia and high dietary salt intake have both been associated with impaired vascular function in adulthood. Using a mouse model of prenatal hypoxia, we examined whether a chronic high salt diet had an additive effect in promoting vascular dysfunction in offspring. Pregnant CD1 dams were placed in a hypoxic chamber (12% O2) or housed under normal conditions (21% O2) from embryonic day 14.5 until birth. Gestational hypoxia resulted in a reduced body weight for both male and female offspring at birth. This restriction in body weight persisted until weaning, after which the animals underwent catch-up growth. At 10 weeks of age, a subset of offspring was placed on a high salt diet (5% NaCl). Pressurized myography of mesenteric resistance arteries at 12 months of age showed that both male and female offspring exposed to maternal hypoxia had significantly impaired endothelial function, as demonstrated by impaired vasodilatation to ACh but not sodium nitroprusside. Endothelial dysfunction caused by prenatal hypoxia was not exacerbated by postnatal consumption of a high salt diet. Prenatal hypoxia increased microvascular stiffness in male offspring. The combination of prenatal hypoxia and a postnatal high salt diet caused a leftward shift in the stress-strain relationship in both sexes. Histopathological analysis of aortic sections revealed a loss of elastin integrity and increased collagen, consistent with increased vascular stiffness. These results demonstrate that prenatal hypoxia programs endothelial dysfunction in both sexes. A chronic high salt diet in postnatal life had an additive deleterious effect on vascular mechanics and structural characteristics in both sexes.

Subtle increases in heart size persist into adulthood in growth restricted babies: the Cardiovascular Risk in Young Finns Study

Background and objectives

Impaired fetal growth is associated with increased cardiovascular morbidity and mortality in adulthood. We sought to determine whether adults born with intrauterine growth restriction have primary maladaptive changes in cardiac structure.

Methods

Study participants were adults (34–49 years) who attended the 31-year follow-up of the Cardiovascular Risk in Young Finns Study (longitudinal cohort). Transthoracic echocardiograms and demographic and cardiovascular risk surveys were completed for 157 adults born small for gestational age (SGA, birth weight <10th population centile) and 627 born average for gestational age (average for gestational age (AGA), birth weight 50th–90th population centile).

Results

Those born growth restricted had subtly enlarged hearts with indexed left ventricular (LV) end-systolic and end-diastolic diameters slightly greater in the SGA individuals than the AGA group (LVESD 18.7 mm/m² SGA vs 18.1 mm/m² AGA, p<0.01; LVEDD 27.5 mm/m² SGA vs 26.6 mm/m² AGA, p<0.01); LV base-to-apex length (47.4 mm/m² SGA vs 46.0 mm/m² AGA, p<0.01); LV basal diameter (26.4 mm/m² SGA vs 25.7 mm/m² AGA, p<0.01); and right ventricular base-to-apex length (40.1 mm/m² SGA vs 39.2 mm/m² AGA, p=0.02). LV stroke volume was greater in those born AGA (74.5 mL SGA vs 78.8 mL AGA, p<0.01), with no significant difference in cardiac output (5 L/min SGA vs 5.2 L/min AGA, p=0.06), heart rate, diastolic indices or sphericity index.

Conclusions

Adults born SGA have some statistically significant but subtle changes in cardiac structure and function, which are less marked than have been described in childhood, and are unlikely to play a pathogenic role in their elevated cardiovascular risk.

Preterm Birth Is Associated with Higher Uric Acid Levels in Adolescents

OBJECTIVE

To compare serum uric acid levels in adolescents born prematurely and adolescents born at term and to assess the correlation between serum uric acid and blood pressure (BP) in those born prematurely.

STUDY DESIGN

In this observational cohort study, 124 adolescents born prematurely and 44 adolescents born at term were studied at 14 years of age. Multivariate analyses were used to describe the relationship of premature birth to serum uric acid while adjusting for confounding variables. Pearson correlation was used to describe the relationship between uric acid and systolic BP among those born prematurely.

RESULTS

Adjusting for race, sex, maternal hypertension, and fetal growth, we found that preterm adolescents had greater serum uric acid levels than adolescents born at term (adjusted mean difference 0.46, 95% CI 0.10-0.81 mg/dL; 27.4, 6-48.2 μmol/L; P = .012). Among those born prematurely, uric acid was positively correlated with systolic BP (Pearson correlation coefficient: 0.29, 0.12-0.44; P = .0013).

CONCLUSIONS

Serum uric acid levels are greater in adolescents born prematurely than in those born at term, and this difference could contribute to greater BP among individuals born prematurely.

Birthweight, mediating biomarkers and the development of type 2 diabetes later in life: a prospective study of multi-ethnic women

AIMS/HYPOTHESIS

The aim of this work was to investigate the prospective relationship between low birthweight (LBW) and type 2 diabetes risk later in life and the mediation effects of type 2 diabetes biomarkers linking LBW to type 2 diabetes risk.

METHODS

We measured baseline plasma concentrations of various type 2 diabetes biomarkers in 1,259 incident type 2 diabetes cases and 1,790 controls in the Women's Health Initiative-Observational Study. Self-report birthweights of the participants were recorded. The total effect of LBW on type 2 diabetes risk was partitioned into effects that were mediated by a specific biomarker and effects that were not mediated by this biomarker, using counterfactual model-based mediation analysis.

RESULTS

LBW was significantly associated with increased risk of type 2 diabetes. Compared with women with birthweight 3.63-4.54 kg, women with LBW (<2.72 kg) had a multivariable-adjusted OR of 2.15 (95% CI, 1.54, 3.00). Insulin resistance (indicated by HOMA-IR) mediated 47% of the total effect. Decreased sex hormone-binding globulin (SHBG) concentration accounted for 24%, elevated E-selectin concentration accounted for 25% and increased systolic blood pressure accounted for 8% of the total effect of LBW on type 2 diabetes risk. (Due to interactions among different mediators, the sum of each individual mediator's contribution could exceed 100%, without an upper limit.)

CONCLUSIONS/INTERPRETATION

LBW is directly predictive of higher risk of type 2 diabetes later in life. The effect of LBW on type 2 diabetes risk seems mainly mediated by insulin resistance, which is further explained by circulating levels of SHBG and E-selectin and systolic blood pressure. The study provides potential risk stratification in a population at greater risk of developing type 2 diabetes.

In adolescence, extreme prematurity is associated with significant changes in the microvasculature, elevated blood pressure and increased carotid intima-media thickness

OBJECTIVES

Increased carotid intima-media thickness (cIMT) and loss of capillary density are antecedents of cardiovascular disease in adults. Former preterm infants are at risk for metabolic precursors of vascular disease, but vascular changes have not yet been studied in this population.

PATIENTS AND METHODS

In 54 former preterm (birth weigh (BW) 753±152 g) and 12 term children (BW 3395±558 g), functional vessel density (FVD) on the forearm and cIMT were obtained at a mean (±SD) age of 11.8±1.5 years. FVD was measured using sidestream dark field imaging before, during and after arterial occlusion, and cIMT using high resolution B-mode ultrasonography. Statistical comparisons were made using the t test, Mann-Whitney U test and the sign test for symmetry, with a two-sided p value as appropriate.

RESULTS

The systolic blood pressure of the former preterm children was significantly increased compared to reference values (females 119±8, z score 1.23; males 118±11, z score 1.14 mm Hg), as were the cIMT values (0.45±0.03 mm vs 0.38±0.04 mm; p<0.001). FVD was significantly higher in former preterm children compared to controls at baseline (mean±SD 33.6±14.5 cm/cm(2) vs 23.0±7.1 cm/cm(2); p=0.002) with decreased reactivity during arterial occlusion (χ(2) 7.14, p=0.008).

CONCLUSIONS

Preterm birth is associated with significant permanent alteration in the microcirculation and increased cIMT and systolic blood pressure. It is unknown whether these changes are due to preterm birth and rapid maturation of the skin or to nutritional factors, as previously thought. This is an important area of future research.

Association of parental blood pressure with retinal microcirculatory abnormalities indicative of endothelial dysfunction in children

OBJECTIVE

Microcirculatory abnormalities precede the onset of hypertension and may explain its familial nature. We examined the relationship between parental blood pressure (BP) and offspring retinal microvasculature in Pakistani trios [father, mother, and child (aged 9-14 years)].

METHODS

This is a substudy of a population-based trial of BP reduction. Data were available on 358 normotensive, and 410 offspring of at least one hypertensive parent. Retinal vessel characteristics were measured from digital images. Multivariable linear regression models were built to assess the associations between maternal and paternal BP and offspring retinal microvasculature.

RESULTS

Optimality deviation was greatest in offspring of two hypertensive parents, compared with those with one or no hypertensive parent (P=0.030 for trend). Paternal SBP and DBP were each significantly associated with optimality deviation in offspring (P=0.023 and P=0.006, respectively). This relationship persisted after accounting for offspring cardiovascular risk factors [increase in optimality deviation (95% confidence interval, CI) 0.0053 (0.0001-0.0106, P=0.047) and 0.0109 (0.0025-0.0193, P=0.011), for each 10 mmHg increase in paternal SBP and DBP, respectively]. Maternal DBP was inversely associated with offspring arteriovenous ratio -0.0102 (-0.0198 to -0.0007, P=0.035).

CONCLUSION

Microvascular endothelial dysfunction in children is associated with increasing levels of parental hypertension. The association with paternal BP is independent of other cardiovascular risk factors, including the child's BP. Higher maternal DBP is associated with evidence of arteriolar narrowing in offspring. These early microcirculatory changes may help explain familial predisposition to hypertension in people of Pakistani origin at an early age.

VIDEO ABSTRACT

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Intrauterine nutrition: long-term consequences for vascular health

There is a growing body of evidence that improper intrauterine nutrition may negatively influence vascular health in later life. Maternal malnutrition may result in intrauterine growth retardation and, in turn, metabolic disorders such as insulin resistance, diabetes, hypertension, and dyslipidemia, and also enhanced risk of atherosclerosis and cardiovascular death in the offspring. Energy and/or protein restriction is the most critical determinant for fetal programming. However, it has also been proposed that intrauterine n-3 fatty acid deficiency may be linked to later higher blood pressure levels and reduced insulin sensitivity. Moreover, it has been shown that inadequate supply of micronutrients such as folate, vitamin B12, vitamin A, iron, magnesium, zinc, and calcium may contribute to impaired vascular health in the progeny. In addition, hypertensive disorders of pregnancy that are linked to impaired placental blood flow and suboptimal fetal nutrition may also contribute to intrauterine growth retardation and aggravated cardiovascular risk in the offspring. On the other hand, maternal overnutrition, which often contributes to obesity and/or diabetes, may result in macrosomia and enhanced cardiometabolic risk in the offspring. Progeny of obese and/or diabetic mothers are relatively more prone to develop obesity, insulin resistance, diabetes, and hypertension. It was demonstrated that they may have permanently enhanced appetites. Their atheromatous lesions are usually more pronounced. It seems that, particularly, a maternal high-fat/junk food diet may be detrimental for vascular health in the offspring. Fetal exposure to excessive levels of saturated fatty and/or n-6 fatty acids, sucrose, fructose and salt, as well as a maternal high glycemic index diet, may also contribute to later enhanced cardiometabolic risk.

Low birthweight and risk of albuminuria in living kidney donors

Low birthweight is linked to hypertension, chronic kidney disease and even end-stage renal disease. We hypothesized that living kidney donors born with lower birthweight may be at increased risk of hypertension, albuminuria, or reduced GFR beyond what is typical following uninephrectomy. Two hundred fifty-seven living kidney donors who donated at the University of Minnesota between 1967 and 2005 underwent iohexol GFR and urinary albumin excretion measurements. Predictors of iohexol GFR <60 mL/min/1.73 m(2), albuminuria, and hypertension were examined using logistic regression. Predictors examined include age at GFR measurement, time since donation, BMI, gender, serum creatinine level (at donation and GFR measurement), systolic and diastolic blood pressure, race, and birthweight. The latter was obtained through self-report and verified through birth certificates and family members. Older age, higher BMI, and time from donation were associated with reduced GFR. Older age and higher BMI were also associated with hypertension. Birthweight was not associated with GFR <60 mL/min/1.73 m(2): OR=0.70, 95% CI (0.28, 1.74), p = 0.45 or hypertension: OR=0.92, 95% CI (0.46, 1.84), p = 0.82 but was associated with albuminuria: OR=0.37, 95% CI (0.15, 0.92), p = 0.03. These data further strengthen the link between low birthweight and potential adverse renal outcomes.

Nutrient-restricted fetus and the cardio–renal connection in hypertensive offspring

A suboptimal intrauterine environment has a number of deleterious effects on fetal development and postpartum health outcomes. Epidemiological studies on several human populations have linked socioeconomic status and low birth weight to an increased incidence of diseases such as hypertension, diabetes, obesity and cardiovascular disease. A growing number of experimental studies in a variety of animal models demonstrate that maternal stressors, such as nutrition and reduced uterine perfusion, affect the intrauterine milieu and result in increased blood pressure in offspring. Several mechanisms appear to contribute to hypertension, including vascular dysfunction and increased peripheral resistance, altered cardio-renal structure and alterations in cardio-renal function. Although many studies have characterized models of developmentally generated hypertension, few have begun to seek therapeutic modalities to ameliorate its incidence. This review discusses recent work that refines hypotheses linking a suboptimal intrauterine environment to cardiovascular and renal phenotypes that have increased susceptibility to cardiovascular disease and hypertension.

Arterial endothelium-derived hyperpolarization: potential role in pregnancy adaptations and complications

Pregnancy encompasses substantial changes in vascular function to accommodate dramatic increases in blood volume and uteroplacental blood flow to the growing fetus. Despite increased hemodynamics, decreased peripheral resistance results in a reduction in mean arterial blood pressure. Vascular tone, and hence peripheral resistance, is determined by a delicate balance of constrictor and dilator capacities. In the normal physiological response to pregnancy, endothelial-derived hyperpolarization (EDH) has been shown to be a major contributor; both EDH and nitric oxide (NO) are predominantly involved in providing an increased vascular capacity for vasodilation. The ability of EDH and NO to adequately accommodate increased blood volume is tested in pathological states such as placental insufficiency or diabetes and both EDH and NO-dependent mechanisms seem to be impacted in these situations. Pregnancy complications also have an impact on the cardiovascular health of the offspring. In adult offspring born from complicated pregnancies, the data suggest that EDH mechanisms are largely maintained, whereas NO is commonly reduced. A diversity of EDH mechanisms may be useful in providing many targets for potential therapeutic avenues for compromised pregnancies; however, further research delineating the mechanisms of EDH and the interactions of NO and EDH, in normal and pathological pregnancies is required.

Time-related arterial changes after allogeneic hematopoietic stem cell transplantation in children

BACKGROUND

Metabolic syndrome is a frequent late effect in young adults after hematopoietic stem cell transplantation (HSCT) performed in childhood.

METHODS

To further study the signs of cardiovascular changes in HSCT patients, we performed noninvasive vascular ultrasonic measurements of arterial stiffness and endothelial function in 25 children (median age: 11.2 y) and in 22 healthy matched controls.

RESULTS

The distensibility of the common carotid artery (CCA) was significantly lower in the patients than in the controls (mean = 0.48, SD = 0.19 vs. mean = 0.64 mm Hg(-1) × 10(-2), SD = 0.28; P = 0.024). The distensibility decreased with time passed after HSCT (P = 0.009). The compliance of the CCA was decreased (mean = 0.10, SD = 0.04 vs. mean = 0.13 mm(2) × mm Hg(-1), SD = 0.05; P = 0.041), and the incremental elastic modulus (E inc) was higher in the patients than in the controls (mean = 2.05, SD = 0.7 vs. mean = 1.6 mm × 10(3), SD = 0.6; P = 0.019). E inc was associated with time passed after HSCT (P = 0.036). The size of the brachial artery and flow-mediated dilation did not differ between the groups.

CONCLUSION

Early mechanical changes of the arterial wall were found at young age after HSCT. Ultrasonography may offer a noninvasive method to find early alterations of the vascular bed and to optimize prevention of atherosclerosis in HSCT patients.

Cardiovascular function in children born very preterm after intrauterine growth restriction with severely abnormal umbilical artery blood flow

AIMS

Low birthweight has been linked to increased cardiovascular risk in adulthood. We evaluated the effect on cardiovascular outcome of intrauterine growth restriction (IUGR) with abnormal fetal blood flow in children born very preterm.

METHODS

Blood pressure, cardiac function and size, diameters, distensibility, and stiffness of the abdominal aorta, carotid, and popliteal arteries, and endothelial function were assessed non-invasively in 7-year-old children (n = 32) born very preterm with IUGR, with birthweight (median, range) 650 g (395-976 g) and gestational age 27 weeks (24-29 weeks). In addition, intima-media thickness was measured in the carotid artery. Controls were matched for gender and age and had birthweight appropriate-for-gestational-age (AGA). The study included 32 preterm-AGA children with birthweight 1010 g (660-1790) g and 32 term-AGA children with birthweight 3530 g (3000-4390) g.

RESULTS

Preterm-IUGR children had lower microvascular response to acetylcholine, lower aortic stiffness, and higher distensibility compared with the preterm-AGA group (p = 0.019, p = 0.001, and p < 0.001, respectively) and lower carotid intima-media thickness compared with the term-AGA group (p = 0.047). The highest aortic β and lowest distensibility were found in the preterm-AGA group. Height-adjusted systolic blood pressure was higher in the preterm groups than in the term-AGA group (p = 0.018). Cardiac function and size did not differ between the groups.

CONCLUSION

IUGR and preterm birth appear to be associated with structural changes in the arterial wall, whereas preterm birth seems to be associated with higher blood pressure. Using conventional echocardiography, we observed no effect of IUGR on cardiac size and function.

Developmental programming of hypertension and kidney disease

A growing body of evidence supports the concept that changes in the intrauterine milieu during "sensitive" periods of embryonic development or in infant diet after birth affect the developing individual, resulting in general health alterations later in life. This phenomenon is referred to as "developmental programming" or "developmental origins of health and disease." The risk of developing late-onset diseases such as hypertension, chronic kidney disease (CKD), obesity or type 2 diabetes is increased in infants born prematurely at <37 weeks of gestation or in low birth weight (LBW) infants weighing <2,500 g at birth. Both genetic and environmental events contribute to the programming of subsequent risks of CKD and hypertension in premature or LBW individuals. A number of observations suggest that susceptibility to subsequent CKD and hypertension in premature or LBW infants is mediated, at least in part, by reduced nephron endowment. The major factors influencing in utero environment that are associated with a low final nephron number include uteroplacental insufficiency, maternal low-protein diet, hyperglycemia, vitamin A deficiency, exposure to or interruption of endogenous glucocorticoids, and ethanol exposure. This paper discusses the effect of premature birth, LBW, intrauterine milieu, and infant feeding on the development of hypertension and renal disease in later life as well as examines the role of the kidney in developmental programming of hypertension and CKD.

Role of birth weight and postnatal growth on pulse wave velocity in teenagers

PURPOSE

Low birth weight and accelerated postnatal growth appear to play a significant role in the pathogenesis of hypertension and cardiovascular disease in adulthood. The aim of the present study was to characterize the factors determining pulse wave velocity (PWV) in teenagers and, in particular, to verify the relationship with birth weight, postnatal growth, timing of adiposity rebound, lifestyle, and hemodynamic parameters.

METHODS

Carotid-femoral and carotid-radial pulse wave velocities of 558 healthy teenagers (age range: 16.2-19.9 years) were determined by means of a PulsePen tonometer. Birth weight and gestational age were obtained from obstetrical records, and data regarding postnatal growth were obtained from pediatric clinical records.

RESULTS

No change in aortic PWV was found in association with birth weight, postnatal growth, and timing of adiposity rebound. However, the study showed a strong association between accelerated growth from 0 to 12 months and carotid-radial PWV (trend: p = .02). Subjects with birth weight values <2,500 g showed higher values of upper limb PWV (p < .05) and higher values of diastolic and mean arterial pressure (p < .05). Stepwise regression analysis revealed that mean arterial pressure, age, and height were the main independent factors determining aortic PWV in this young population.

CONCLUSIONS

These results suggest that there is no linear correlation between birth weight and hemodynamic parameters in teenagers; however, subjects characterized by very low birth weight and accelerated postnatal weight gain appear to demonstrate increased upper limb PWV and diastolic and mean arterial pressure values.

Impact of fetal programming, birth weight, and infant feeding on later hypertension

The concept of developmental origins of adult disease derives from both epidemiologic and basic sciences. This brief review considers the impact of the intrauterine milieu, intrauterine growth retardation, premature birth, and infant feeding on later hypertension and kidney disease.

The effect of hypoxia-induced intrauterine growth restriction on renal artery function

The risk of developing cardiovascular diseases is known to begin before birth and the impact of the intrauterine environment on subsequent adult health is currently being investigated from many quarters. Following our studies demonstrating the impact of hypoxiain uteroand consequent intrauterine growth restriction (IUGR) on the rat cardiovascular system, we hypothesized that changes extend throughout the vasculature and alter function of the renal artery. In addition, we hypothesized that hypoxia induces renal senescence as a potential mediator of altered vascular function. We demonstrated that IUGR females had decreased responses to the adrenergic agonist phenylephrine (PE; pEC506.50 ± 0.05 controlv. 6.17 ± 0.09 IUGR,P< 0.05) and the endothelium-dependent vasodilator methylcholine (MCh;Emax89.8 ± 7.0% controlv. 41.0 ± 6.5% IUGR,P< 0.001). In IUGR females, this was characterised by increased basal nitric oxide (NO) modulation of vasoconstriction (PE pEC506.17 ± 0.09 IUGRv. 6.42 ± 0.08 in the presence of the NO synthase inhibitorN-nitro-l-arginine methyl ester hydrochloride (l-NAME;P< 0.01) but decreased activated NO modulation (no change in MCh responses in the presence ofl-NAME), respectively. In contrast, IUGR males had no changes in PE or MCh responses but demonstrated increased basal NO (PE pEC506.29 ± 0.06 IUGRv. 6.42 ± 0.12 plusl-NAME,P< 0.01) and activated NO (Emax37.8 ± 9.4% controlv. −0.8 ± 13.0% plusl-NAME,P< 0.05) modulation. No significant changes were found in gross kidney morphology, proteinuria or markers of cellular senescence in either sex. In summary, renal vascular function was altered by hypoxiain uteroin a sex-dependent manner but was unlikely to be mediated by premature renal senescence.

Faria T, Siman FDM, Silveira EA, Meira EF, da Costa CP, Vassallo DV, Padilha AS. Post-weaning protein malnutrition increases blood pressure and induces endothelial dysfunctions in rats

Malnutrition during critical periods in early life may increase the subsequent risk of hypertension and metabolic diseases in adulthood, but the underlying mechanisms are still unclear. We aimed to evaluate the effects of post-weaning protein malnutrition on blood pressure and vascular reactivity in aortic rings (conductance artery) and isolated-perfused tail arteries (resistance artery) from control (fed with Labina®) and post-weaning protein malnutrition rats (offspring that received a diet with low protein content for three months). Systolic and diastolic blood pressure and heart rate increased in the post-weaning protein malnutrition rats. In the aortic rings, reactivity to phenylephrine (10(-10)-3.10(-4) M) was similar in both groups. Endothelium removal or L-NAME (10(-4) M) incubation increased the response to phenylephrine, but the L-NAME effect was greater in the aortic rings from the post-weaning protein malnutrition rats. The protein expression of the endothelial nitric oxide isoform increased in the aortic rings from the post-weaning protein malnutrition rats. Incubation with apocynin (0.3 mM) reduced the response to phenylephrine in both groups, but this effect was higher in the post-weaning protein malnutrition rats, suggesting an increase of superoxide anion release. In the tail artery of the post-weaning protein malnutrition rats, the vascular reactivity to phenylephrine (0.001-300 µg) and the relaxation to acetylcholine (10(-10)-10(-3) M) were increased. Post-weaning protein malnutrition increases blood pressure and induces vascular dysfunction. Although the vascular reactivity in the aortic rings did not change, an increase in superoxide anion and nitric oxide was observed in the post-weaning protein malnutrition rats. However, in the resistance arteries, the increased vascular reactivity may be a potential mechanism underlying the increased blood pressure observed in this model.

Mechanisms of fetal programming in hypertension

Events that occur in the early fetal environment have been linked to long-term health and lifespan consequences in the adult. Intrauterine growth restriction (IUGR), which may occur as a result of nutrient insufficiency, exposure to hormones, or disruptions in placental structure or function, may induce the fetus to alter its developmental program in order to adapt to the new conditions. IUGR may result in a decrease in the expression of genes that are responsible for nephrogenesis as nutrients are rerouted to the development of more essential organs. Fetal survival under these conditions often results in low birth weight and a deficit in nephron endowment, which are associated with hypertension in adults. Interestingly, male IUGR offspring appear to be more severely affected than females, suggesting that sex hormones may be involved. The processes of fetal programming of hypertension are complex, and we are only beginning to understand the underlying mechanisms.

Basal and post-ischemic vascular compliance in children/adolescents born small for gestational age

BACKGROUND

Intrauterine growth restriction plays a powerful role in influencing later susceptibility to certain chronic diseases, such as hypertension. Endothelial dysfunction and arterial stiffness are early events in the development of cardiovascular diseases (CVDs). We have studied vascular compliance in small for gestational age (SGA) children/adolescents in comparison with that in appropriate for gestational age (AGA) subjects.

METHODS

We monitored blood pressure, vascular resistance and compliance in 82 children-adolescents (52 SGA, 30 AGA), by means of pulse wave analysis (CR 2000 HDI) at the radial level, before and after 3 min of ischemic stress at the brachial level.

RESULTS

In the children/adolescents born SGA we found a significant increase in systolic and diastolic blood pressure and vascular resistance in the basal condition; the large and small vessels were stiffer. After ischemia we observed an increased vascular response in the SGA children/adolescents: there was a great diminution of systolic and diastolic blood pressure and a larger increase of the elasticity of the conduit and resistance vessels.

CONCLUSIONS

These data show that the SGA group presented some early signs of arterial wall functional disorders. More pediatric data are needed for the evaluation by non-invasive techniques of vascular function in children-adolescents at risk of CVD.

Fetal Growth and Preterm Birth Influence Cardiovascular Risk Factors and Arterial Health in Young Adults

Objective—

Impaired fetal growth is associated with cardiovascular disease in adulthood. The mechanisms of this association remain poorly described. We aimed to determine the associations of impaired fetal growth and preterm birth with cardiovascular risk factors and arterial health in a large cohort of young adults.

Methods and Results—

Carotid intima-media thickness, brachial flow-mediated dilatation and cardiovascular risk factors were compared between young adults (24–45 years) born at term with impaired fetal growth (birth weight <10th percentile; n=207), born preterm (<37 weeks' gestation; n=253), and a control group born at term with normal fetal growth (birth weight 50–90th percentile; n=835), in the Cardiovascular Risk in Young Finns study. Compared with controls, those with impaired fetal growth had elevated triglycerides ( P =0.006), C-reactive protein ( P =0.004), low-density lipoprotein cholesterol, systolic blood pressure (both P =0.06), and intima-media thickness and impaired flow-mediated dilatation (both P =0.02), the latter partially mediated by systolic blood pressure, C-reactive protein, and triglycerides. Those born preterm had higher intima-media thickness ( P =0.005) and lower flow-mediated dilatation ( P =0.03) compared with controls, although this was restricted to those with concurrent fetal growth restriction.

Conclusion—

Impaired fetal growth is associated with impaired endothelial function and elevated preclinical atherosclerosis in young adults, partly mediated by inflammation, blood pressure, and triglycerides. This association is most marked for those also born preterm.

Low Birth Weight Infants Do Not Have Capillary Rarefaction at Birth

Low birth weight predicts adult essential hypertension and is linked to increased cardiovascular mortality in adult life. A reduction in capillary density (ie, rarefaction) is a hallmark of essential hypertension, and evidence suggests that rarefaction precedes the onset of the rise in blood pressure, because it is found in normotensive individuals at high risk of developing hypertension, suggesting that rarefaction is likely to be a primary structural abnormality. We hypothesized that low birth weight infants would have significant capillary rarefaction at birth. We studied 44 low birth weight infants born to normotensive mothers (33 were born preterm, birth weight: 1823±446 g; and 11 were born at term, birth weight: 2339±177 g) and compared them with 71 infants born at term with normal weight (birth weight: 3333±519 g). We used orthogonal polarized spectroscopy to measure basal (ie, functional) and maximal (ie, structural) skin capillary densities. Low birth weight infants, whether born preterm or at term, had significantly higher functional capillary density (mean difference of 10.5 capillaries per millimeter squared; 95% CI: 6.6–14.4 capillaries per millimeter squared; P <0.0001) and higher structural capillary density (mean difference of 11.1 capillaries per millimeter squared; 95% CI: 7.6–14.5 capillaries per millimeter squared; P <0.0001) when compared with normal weight term infants. We conclude that low birth weight infants born to normotensive mothers do not have capillary rarefaction at birth. These results contradict what might have been predicted from the concept of the intrauterine origins of adult disease and suggest that microcirculatory abnormalities observed in individuals of low birth weight occur in postnatal life rather than during their intrauterine existence.

Maternal antioxidant blocks programmed cardiovascular and behavioural stress responses in adult mice

Intra-uterine growth restriction is an independent risk factor for adult psychiatric and cardiovascular diseases. In humans, intra-uterine growth restriction is associated with increased placental and fetal oxidative stress, as well as down-regulation of placental 11β-HSD (11β-hydroxysteroid dehydrogenase). Decreased placental 11β-HSD activity increases fetal exposure to maternal glucocorticoids, further increasing fetal oxidative stress. To explore the developmental origins of co-morbid hypertension and anxiety disorders, we increased fetal glucocorticoid exposure by administering the 11β-HSD inhibitor CBX (carbenoxolone; 12 mg·kg-1 of body weight·day-1) during the final week of murine gestation. We hypothesized that maternal antioxidant (tempol throughout pregnancy) would block glucocorticoid-programmed anxiety, vascular dysfunction and hypertension. Anxiety-related behaviour (conditioned fear) and the haemodynamic response to stress were measured in adult mice. Maternal CBX administration significantly increased conditioned fear responses of adult females. Among the offspring of CBX-injected dams, maternal tempol markedly attenuated the behavioural and cardiovascular responses to psychological stress. Compared with offspring of undisturbed dams, male offspring of dams that received daily third trimester saline injections had increased stress-evoked pressure responses that were blocked by maternal tempol. In contrast, tempol did not block CBX-induced aortic dysfunction in female mice (measured by myography and lucigenin-enhanced chemiluminescence). We conclude that maternal stress and exaggerated fetal glucocorticoid exposure enhance sex-specific stress responses, as well as alterations in aortic reactivity. Because concurrent tempol attenuated conditioned fear and stress reactivity even among the offspring of saline-injected dams, we speculate that antenatal stressors programme offspring stress reactivity in a cycle that may be broken by antenatal antioxidant therapy.

Early and late postnatal myocardial and vascular changes in a protein restriction rat model of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a risk factor for cardiovascular disease in later life. Early structural and functional changes in the cardiovascular system after IUGR may contribute to its pathogenesis. We tested the hypothesis that IUGR leads to primary myocardial and vascular alterations before the onset of hypertension. A rat IUGR model of maternal protein restriction during gestation was used. Dams were fed low protein (LP; casein 8.4%) or isocaloric normal protein diet (NP; casein 17.2%). The offspring was reduced to six males per litter. Immunohistochemical and real-time PCR analyses were performed in myocardial and vascular tissue of neonates and animals at day 70 of life. In the aortas of newborn IUGR rats expression of connective tissue growth factor (CTGF) was induced 3.2-fold. At day 70 of life, the expression of collagen I was increased 5.6-fold in aortas of IUGR rats. In the hearts of neonate IUGR rats, cell proliferation was more prominent compared to controls. At day 70 the expression of osteopontin was induced 7.2-fold. A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed. The myocardial expression and deposition of collagens was more prominent in IUGR animals compared to controls at day 70. In the low-protein diet model, IUGR leads to changes in the expression patterns of profibrotic genes and discrete structural abnormalities of vessels and hearts in adolescence, but, with the exception of CTGF, not as early as at the time of birth. Invasive and non-invasive blood pressure measurements confirmed that IUGR rats were normotensive at the time point investigated and that the changes observed occurred independently of an increased blood pressure. Hence, altered matrix composition of the vascular wall and the myocardium may predispose IUGR animals to cardiovascular disease later in life.

Flow-mediated vasodilation is impaired in adult rat offspring exposed to prenatal hypoxia

There is now a demonstrated association between low birth weight and increased mortality later in life. Changes in fetal development may program the cardiovascular system and lead to an increased risk of cardiovascular diseases later in life. In addition, aging is a risk factor for vascular endothelial-dependent dysfunction. However, the impact of being born intrauterine growth restricted (IUGR) on the normal aging mechanisms of vascular dysfunction is not clear. We hypothesized that IUGR would cause changes in vascular function that would affect the mechanisms of flow-induced vasodilation later in life in an age- or sex-dependent manner. To create an IUGR model, pregnant Sprague-Dawley rats were placed in a hypoxic (11.5% O2) or control (room air, 21% O2) environment from days 15 to 21 of pregnancy. Both male and female offspring were investigated at 4 or 12 mo of age. Vascular function was assessed in small mesenteric arteries using flow-induced vasodilation, a physiological stimuli of vasodilation, in a pressure myograph. Flow-induced vasodilation was unaffected at a young age, but was significantly reduced in aging IUGR compared with aging controls ( P < 0.05). Underlying vasodilator mechanisms were altered such that nitric oxide-mediated vasodilation was abolished in both young adult and aging IUGR males and females and in aging control females ( P > 0.05). Endothelium-derived hyperpolarizing factor-mediated vasodilation was maintained in all groups ( P < 0.01). A change in the mechanisms of vasodilation occurring at an earlier age in IUGR offspring may predispose them to develop cardiovascular diseases as an aging adult.

Reduced brachial flow-mediated vasodilation in young adult ex extremely low birth weight preterm: a condition predictive of increased cardiovascular risk?

BACKGROUND

Sporadic data present in literature report how preterm birth and low birth weight constitute the risk factors for the development of cardiovascular diseases in later life.

AIM

To assess the presence of potential alterations to endothelial function in young adults born preterm at extremely low birth weight (<1000 g; ex ELBW).

METHOD

Thirty-two ex-ELBW subjects (10 males [M] and 22 females [F], aged 17-28 years, mean [+/- DS] 20.1 +/- 2.5 years) were compared with 32 healthy, age-matched subjects born at term (C, 9 M and 23 F).

EXCLUSION CRITERIA

1) pathological conditions known to affect endothelial function; 2) administration of drugs known to affect endothelial function. Endothelial function was assessed by non-invasive finger plethysmography, previously validated by the US Food and Drug Administration (Endopath; Itamar Medical Ltd., Cesarea, Israel).

RESULTS

Endothelial function was significantly reduced in ex-ELBW subjects compared to C (1.94 +/- 0.37 vs. 2.68 +/- 0.41, p < 0.0001). Moreover, this function correlated significantly with gestational age (r = 0.56, p < 0.0009) and birth weight (r = 0.63, p < 0.0001).

CONCLUSIONS

The results obtained reveal a significant decrease in endothelial function of ex-ELBW subjects compared to controls, underlining a probable correlation with preterm birth and low birth weight. Taken together, these results suggest that an ELBW may underlie the onset of early circulatory dysfunction predictive of increased cardiovascular risk.