Restriction of maternal protein intake during rat pregnancy produces offspring that are hypertensive in adulthood, but the mechanisms are not well understood. Our purpose was to determine whether this adult hypertension could be programmed during development by suppression of the fetal/newborn reninangiotensin system (RAS) and a consequent reduction in nephron number. Pregnant rats were fed a normal protein (19%, NP) or low-protein (8.5%, LP) diet throughout gestation. Birth weight was reduced by 13% (p Ͻ 0.0005), and the kidney/body weight ratio was reduced in LP pups. Renal renin mRNA levels were significantly reduced in newborn LP pups; renal renin concentration and renin immunostaining were suppressed. Renal tissue angiotensin II levels were also suppressed in newborn LP (0.079 Ϯ 0.002 ng/mg, LP versus 0.146 Ϯ 0.016 ng/mg, NP, p Ͻ 0.01). Mean arterial pressure in conscious, chronically instrumented adult offspring (21 wk) was higher in LP (135 Ϯ 1 mm Hg, LP versus 126 Ϯ 1 mm Hg, NP, p Ͻ 0.00007), and GFR normalized to kidney weight was reduced in LP (p Ͻ 0.04). The number of glomeruli per kidney was lower in adult LP offspring (21,567 Ϯ 1,694, LP versus 28,917 Ϯ 2,342, NP, p Ͻ 0.03), and individual glomerular volume was higher (1.81 Ϯ 0.16 10 6 m 3 , LP versus 1.11 Ϯ 0.10 10 6 m 3 , NP, p Ͻ 0.005); the total volume of all glomeruli per kidney was not significantly different. Thus, perinatal protein restriction in the rat suppresses the newborn intrarenal RAS and leads to a reduced number of glomeruli, glomerular enlargement, and hypertension in the adult. Abbreviations RAS, renin-angiotensin system ERPF, effective renal plasma flow NP, normal protein (19%) diet LP, low-protein (8.5%) diet ANGII, angiotensin II PAH, para-amino hippurate A decade ago, Barker et al. first reported an inverse relationship between birth weight and death from cardiovascular disease in adulthood (1). Subsequently, a number of epidemiologic studies in different parts of the world have found a relationship between early growth patterns and the risk of cardiovascular disease in adulthood (2-8). Although these findings remain somewhat controversial (9), the majority of evidence indicates that even within the "normal" range of birth weights, babies that are born smaller have a higher risk of death from cardiovascular disease when they reach adulthood. This indicates that some factor or factors in the perinatal environment, probably related at least in part to maternal nutrition, can "program" the individual for increased cardiovascular risk later in life. However, the precise physiologic and molecular mechanisms by which this programming occurs are unknown.Recently, a rat model of perinatal protein restriction has been identified that has several features in common with the observations in humans, suggesting that this may be a good animal model of the human condition. In particular, offspring ABSTRACT460

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Recent evidence indicates a role for the renin-angiotensin system (RAS) in the pathogenesis of glomerular injury in diabetes. To further explore the RAS in diabetes, studies were conducted in nondiabetic control rats and in moderately hyperglycemic diabetic (DM) rats. In DM rats, both acute and chronic therapy with the specific angiotensin II (ANG II) receptor antagonist losartan did not affect glomerular hyperfiltration or hyperperfusion but selectively normalized the glomerular capillary hydraulic pressure and ultrafiltration coefficient. To determine the basis of intrarenal hemodynamic responsiveness to RAS inhibition, we conducted biochemical, molecular biological, and immunohistochemical studies to assess endogenous RAS activity. Values for plasma renin concentration and serum angiotensin-converting enzyme (ACE) activity in DM rats were normal. In contrast, intrarenal renin protein content, and renin and angiotensinogen mRNAs, were increased in DM rats, suggesting disproportionate activation of the intrarenal RAS. Total renal ACE activity was significantly reduced in DM rats, but immunohistochemical studies indicated redistribution of ACE in the diabetic kidney. Proximal tubule ACE activity was reduced, but ACE immunostaining intensity was enhanced in glomeruli and renal vasculature. Together, these observations indicate increased RAS activity in those sites (glomeruli and vasculature) most likely to regulate hemodynamic function, potentially explaining the prominent responses to pharmacological blockade of ANG II formation and/or action.

These recommendations are intended to provide primary care physicians with a useful reference when they are faced with a young child or teenager who presents with proteinuria, whether this is mild and asymptomatic or more severe, leading to nephrotic syndrome.

restriction in the rat leads to hypertension in adult male offspring. The purpose of this study was to determine whether female rats are resistant to developing the increased blood pressure seen in male rats after maternal protein restriction. Pregnant rats were fed a normal protein (19%, NP) or low-protein (8.5%, LP) diet throughout gestation. Renal renin protein and ANG II levels were reduced by 50 -65% in male LP compared with NP pups, but were not suppressed in female LP compared with female NP. Mean arterial pressure in conscious, chronically instrumented adult female offspring (22 wk

Box 1 | Prevailing attitudes of medical professionals emerging from public review and participant survey Agreement with goal of standardizing nomenclature, with acknowledgment of challenges Regarded multiplicity of terms and lack of adherence to established definitions as confusing and potentially leading to errors Anticipated that a standardized nomenclature would help foster consistency in trial design, execution, and reporting Judged consistency between terms used in scholarly and patient communities to be an important goal, but not one overriding the need for precision and efficiency Journal editors strongly agreed that having a more standardized nomenclature for kidney disease would be useful for their journals, but they anticipated time constraints of journal personnel to be the biggest barrier to implementation Qualified endorsement of replacing "renal" with "kidney" Felt that foregrounding "kidney" would be easier for patients and their families Perceived a greater likelihood of raising awareness, attracting funding, and influencing public policy with consistent use of "kidney" Cautioned against a wholesale switch because "renal" may be less awkward in some contexts and may be necessary in others (e.g., ESRD as a CMS definition) Dissatisfaction with "end-stage" as a descriptor of kidney disease Recognized that this wording can be demoralizing and stigmatizing for patients Considered the implication of imminent death to be outdated Frustrated by imprecision in its use (ranging from being a synonym for dialysis patients to a descriptor of patients with kidney failure with or without kidney replacement therapy) Recognition of the need for ongoing attention to nomenclature issues Noted that standardization of nomenclature is dependent on uptake of consensus definitions B where definitions are in flux or are more contentious, standardization of that nomenclature set may be premature B enhancing adoption of definitions requires continued effort Highlighted the need for harmonization with ongoing, broader-scope ontology efforts Expected that improved understanding of molecular mechanisms will lead to more-precise definitions and nomenclature CMS, Centers for Medicare & Medicaid Services; ESRD, end-stage renal disease.

We examined angiotensinogen gene expression in rat kidney by in situ hybridization histochemistry. Using a rat cRNA probe to angiotensinogen, we demonstrated angiotensinogen mRNA to be localized predominantly in the proximal renal tubule, with considerably lesser amounts in distal tubular segments and glomerular tufts. Previous studies have localized renin immunoreactivity to the juxtaglomerular cells, glomerular tufts, and proximal tubules. Such findings provide further evidence for a local tissue renin angiotensin system within the kidney which may influence regional function. Based on our data, we hypothesize that a major site of angiotensin production is the proximal tubule. We postulate that angiotensin synthesized in and/or around the proximal tubule may directly modulate tubular transport of sodium, bicarbonate, and water. In addition to the proximal tubule, the specific localization of the renin angiotensin components elsewhere in the kidney would also support the other proposed regional functions of the intrarenal system, including modulation of tubuloglomerular balance. (J. Clin. Invest. 1990. 85:417-423.) renin -angiotensinogen * kidney-in situ hybridization -RNA

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