Angiotensin II receptor antagonist reduces subsequent uterine arterial dysfunction in pregnant offspring of protein-restricted rat dams

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

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

A proposed mechanism for the Berecek phenomenon with implications for cardiovascular reprogramming

Berecek et al reported in the 1990s that when spontaneously hypertensive rat (SHR) mating pairs were treated with captopril and the resulting pups were continued on the drug for 2 months followed by drug discontinuation, the pups did not develop full blown hypertension, and the cardiovascular structural changes associated with hypertension in SHR were mitigated. The offspring of the pups also displayed diminished hypertension and structural changes, suggesting that the drug therapy produced a heritable amelioration of the SHR phenotype. This observation is reviewed. The link between cellular renin angiotensin systems and epigenetic histone modification is explored, and a mechanism responsible for the observation is proposed. In any case, the observations of Berecek are sufficiently intriguing and biologically important to merit re-exploration and definitive explanation. Equally important is determining the role of renin angiotensin systems in epigenetic modification.

Changes of blood pressure, abdominal visceral fat tissue and gene expressions in fetal programming induced rat model after amlodipine-losartan combination treatment

Background

There are a number of complications that can occur if there is under-nutrition during pregnancy followed by a period of rapid catch-up growth, including a higher chance of adult obesity, insulin resistance and hypertriglyceridemia. The purposes of this study were to investigate the effects of fetal under-nutrition during late pregnancy and lactation on blood pressure, visceral fat tissue, gene expressions and to evaluate changes after amlodipine- losartan combination treatment.

Methods

The rats were divided into three groups: the control (C) group, the food restriction (FR: 50 % food restricted diet) group, and the CX group, which was treated with Cozaar XQ (amlodipine- losartan combination drug) in FR rats from postnatal 4 to 20 weeks. Masson’s trichrome staining was performed in the heart tissues. The amount of abdominal visceral fat tissues was measured. Western blot analysis such as angiotensin converting enzyme (ACE), angiotensin II receptor type IA (ATIA), troponin I (Tn I) and endothelial nitric oxide synthase (eNOS) were performed.

Results

Body weights were significantly higher in the FR group compared with the C group at weeks 8 and 20 and lower in the CX group at week 20. Blood pressure was significantly higher in the FR group compared with the C group at week 20 and lower in the CX group at weeks 12 and 20. The amount of abdominal visceral fat was significantly higher in the FR group compared with the C group at weeks 8, 12 and 20 and significantly lower in the CX group at weeks 16 and 20. Protein expression of ATIA and eNOS were significantly reduced in the CX group at weeks 16 and 20. ACE was significantly reduced in the CX group at week 20 and Tn I was significantly reduced in the CX group at week 16.

Conclusions

When there is fetal under-nutrition during pregnancy, it leads to obesity, high blood pressure, hypertriglyceridemia and several gene changes in offspring. Amlodipine-losartan combination treatment was able to lower obesity, hypertension, hypertriglyceridemia and several gene changes in rats suffering from fetal under-nutrition during pregnancy.

Early developmental conditioning of later health and disease: physiology or pathophysiology?

Extensive experimental animal studies and epidemiological observations have shown that environmental influences during early development affect the risk of later pathophysiological processes associated with chronic, especially noncommunicable, disease (NCD). This field is recognized as the developmental origins of health and disease (DOHaD). We discuss the extent to which DOHaD represents the result of the physiological processes of developmental plasticity, which may have potential adverse consequences in terms of NCD risk later, or whether it is the manifestation of pathophysiological processes acting in early life but only becoming apparent as disease later. We argue that the evidence suggests the former, through the operation of conditioning processes induced across the normal range of developmental environments, and we summarize current knowledge of the physiological processes involved. The adaptive pathway to later risk accords with current concepts in evolutionary developmental biology, especially those concerning parental effects. Outside the normal range, effects on development can result in nonadaptive processes, and we review their underlying mechanisms and consequences. New concepts concerning the underlying epigenetic and other mechanisms involved in both disruptive and nondisruptive pathways to disease are reviewed, including the evidence for transgenerational passage of risk from both maternal and paternal lines. These concepts have wider implications for understanding the causes and possible prevention of NCDs such as type 2 diabetes and cardiovascular disease, for broader social policy and for the increasing attention paid in public health to the lifecourse approach to NCD prevention.