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Alhamoud I, Legan SK, Gattineni J, Baum M. Sex differences in prenatal programming of hypertension by dexamethasone. Exp Biol Med (Maywood) 2021; 246:1554-1562. [PMID: 33794700 DOI: 10.1177/15353702211003294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Prenatal dexamethasone has been shown to increase blood pressure in male offspring but the mechanism for the increase in blood pressure is unclear. The present study examined if prenatal programming by maternal injection of dexamethasone on days 15 and 16 of gestation affected the blood pressure comparably in female and male offspring. Our hypothesis was that males would be affected by prenatal dexamethasone to a greater extent than females and that either an increase in renal tubular transporter abundance or an increase in renin or aldosterone system would be associated with hypertension with prenatal programming. Prenatal dexamethasone increased blood pressure at two months and six months of age and resulted in proteinuria and albuminuria at six months in male but not female rat offspring. There was no effect of prenatal dexamethasone on blood pressure and proteinuria at one month in male and in female offspring. While prenatal dexamethasone increased male renal thick ascending limb sodium potassium two chloride cotransporter protein abundance at two months, prenatal dexamethasone on days 15 and 16 of gestation did not affect transporter abundance in males at other ages, nor did it affect proximal tubule sodium/hydrogen exchanger or distal convoluted tubule sodium chloride cotransporter protein abundance at any age. There was no difference in systemic renin or aldosterone in the prenatal dexamethasone group compared to same sex controls. In conclusion, male but not female offspring have an increase in blood pressure and urinary protein excretion with prenatal dexamethasone. The increase in blood pressure with prenatal programming was not associated with a consistent increase in renal tubular transporter protein abundance, nor plasma renin activity and serum aldosterone.
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Affiliation(s)
- Issa Alhamoud
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9063, USA
| | - Susan K Legan
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9063, USA
| | - Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9063, USA
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9063, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9063, USA
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2
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Developmental programming of cardiovascular function: a translational perspective. Clin Sci (Lond) 2021; 134:3023-3046. [PMID: 33231619 DOI: 10.1042/cs20191210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/11/2022]
Abstract
The developmental origins of health and disease (DOHaD) is a concept linking pre- and early postnatal exposures to environmental influences with long-term health outcomes and susceptibility to disease. It has provided a new perspective on the etiology and evolution of chronic disease risk, and as such is a classic example of a paradigm shift. What first emerged as the 'fetal origins of disease', the evolution of the DOHaD conceptual framework is a storied one in which preclinical studies played an important role. With its potential clinical applications of DOHaD, there is increasing desire to leverage this growing body of preclinical work to improve health outcomes in populations all over the world. In this review, we provide a perspective on the values and limitations of preclinical research, and the challenges that impede its translation. The review focuses largely on the developmental programming of cardiovascular function and begins with a brief discussion on the emergence of the 'Barker hypothesis', and its subsequent evolution into the more-encompassing DOHaD framework. We then discuss some fundamental pathophysiological processes by which developmental programming may occur, and attempt to define these as 'instigator' and 'effector' mechanisms, according to their role in early adversity. We conclude with a brief discussion of some notable challenges that hinder the translation of this preclinical work.
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3
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Nüsken E, Voggel J, Fink G, Dötsch J, Nüsken KD. Impact of early-life diet on long-term renal health. Mol Cell Pediatr 2020; 7:17. [PMID: 33269431 PMCID: PMC7710776 DOI: 10.1186/s40348-020-00109-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
In the last years, great advances have been made in the effort to understand how nutritional influences can affect long-term renal health. Evidence has accumulated that maternal nutrition before and during pregnancy and lactation as well as early postnatal nutrition is of special significance. In this review, we summarize epidemiologic and experimental data on the renal effects of perinatal exposure to energy restriction, low-protein diet, high-fat diet, high-fructose diet, and high- and low-salt diet as well as micronutrient deficiencies. Interestingly, different modifications during early-life diet may end up with similar sequelae for the offspring. On the other hand, molecular pathways can be influenced in opposite directions by different dietary interventions during early life. Importantly, postnatal nutrition significantly modifies the phenotype induced by maternal diet. Sequelae of altered macro- or micronutrient intakes include altered nephron count, blood pressure dysregulation, altered sodium handling, endothelial dysfunction, inflammation, mitochondrial dysfunction, and oxidative stress. In addition, renal prostaglandin metabolism as well as renal AMPK, mTOR, and PPAR signaling can be affected and the renin-angiotensin-aldosterone system may be dysregulated. Lately, the influence of early-life diet on gut microbiota leading to altered short chain fatty acid profiles has been discussed in the etiology of arterial hypertension. Against this background, the preventive and therapeutic potential of perinatal nutritional interventions regarding kidney disease is an emerging field of research. Especially individuals at risk (e.g., newborns from mothers who suffered from malnutrition during gestation) could disproportionately benefit from well-targeted dietary interventions.
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Affiliation(s)
- Eva Nüsken
- Department of Pediatrics and Adolescent Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
| | - Jenny Voggel
- Department of Pediatrics and Adolescent Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Gregor Fink
- Department of Pediatrics and Adolescent Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Jörg Dötsch
- Department of Pediatrics and Adolescent Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Kai-Dietrich Nüsken
- Department of Pediatrics and Adolescent Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
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4
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Torreggiani M, Fois A, D’Alessandro C, Colucci M, Orozco Guillén AO, Cupisti A, Piccoli GB. Of Mice and Men: The Effect of Maternal Protein Restriction on Offspring's Kidney Health. Are Studies on Rodents Applicable to Chronic Kidney Disease Patients? A Narrative Review. Nutrients 2020; 12:E1614. [PMID: 32486266 PMCID: PMC7352514 DOI: 10.3390/nu12061614] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/19/2020] [Accepted: 05/28/2020] [Indexed: 12/20/2022] Open
Abstract
In the almost 30 years that have passed since the postulation of the "Developmental Origins of Health and Disease" theory, it has been clearly demonstrated that a mother's dietary habits during pregnancy have potential consequences for her offspring that go far beyond in utero development. Protein malnutrition during pregnancy, for instance, can cause severe alterations ranging from intrauterine growth retardation to organ damage and increased susceptibility to hypertension, diabetes mellitus, cardiovascular diseases and chronic kidney disease (CKD) later in life both in experimental animals and humans. Conversely, a balanced mild protein restriction in patients affected by CKD has been shown to mitigate the biochemical derangements associated with kidney disease and even slow its progression. The first reports on the management of pregnant CKD women with a moderately protein-restricted plant-based diet appeared in the literature a few years ago. Today, this approach is still being debated, as is the optimal source of protein during gestation in CKD. The aim of this report is to critically review the available literature on the topic, focusing on the similarities and differences between animal and clinical studies.
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Affiliation(s)
- Massimo Torreggiani
- Nephrology and Dialysis, Centre Hospitalier Le Mans, Avenue Roubillard 194, 72000 Le Mans, France; (A.F.); (G.B.P.)
| | - Antioco Fois
- Nephrology and Dialysis, Centre Hospitalier Le Mans, Avenue Roubillard 194, 72000 Le Mans, France; (A.F.); (G.B.P.)
| | - Claudia D’Alessandro
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (C.D.); (A.C.)
| | - Marco Colucci
- Unit of Nephrology and Dialysis, ICS Maugeri S.p.A. SB, Via S. Maugeri 10, 27100 Pavia, Italy;
| | | | - Adamasco Cupisti
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (C.D.); (A.C.)
| | - Giorgina Barbara Piccoli
- Nephrology and Dialysis, Centre Hospitalier Le Mans, Avenue Roubillard 194, 72000 Le Mans, France; (A.F.); (G.B.P.)
- Dipartimento di Scienze Cliniche e Biologiche, Università di Torino, 10100 Torino, Italy
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5
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Baum M. Role of renal sympathetic nerve activity in prenatal programming of hypertension. Pediatr Nephrol 2018; 33:409-419. [PMID: 27001053 DOI: 10.1007/s00467-016-3359-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/15/2016] [Accepted: 02/18/2016] [Indexed: 12/30/2022]
Abstract
Prenatal insults, such as maternal dietary protein deprivation and uteroplacental insufficiency, lead to small for gestational age (SGA) neonates. Epidemiological studies from many different parts of the world have shown that SGA neonates are at increased risk for hypertension and early death from cardiovascular disease as adults. Animal models, including prenatal administration of dexamethasone, uterine artery ligation and maternal dietary protein restriction, result in SGA neonates with fewer nephrons than controls. These models are discussed in this educational review, which provides evidence that prenatal insults lead to altered sodium transport in multiple nephron segments. The factors that could result in increased sodium transport are discussed, focusing on new information that there is increased renal sympathetic nerve activity that may be responsible for augmented renal tubular sodium transport. Renal denervation abrogates the hypertension in programmed rats but has no effect on control rats. Other potential factors that could cause hypertension in programmed rats, such as the renin-angiotensin system, are also discussed.
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Affiliation(s)
- Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Building, Dallas, TX, 75390-9063, USA. .,Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
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Tiu AC, Bishop MD, Asico LD, Jose PA, Villar VAM. Primary Pediatric Hypertension: Current Understanding and Emerging Concepts. Curr Hypertens Rep 2017; 19:70. [PMID: 28780627 PMCID: PMC6314210 DOI: 10.1007/s11906-017-0768-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The rising prevalence of primary pediatric hypertension and its tracking into adult hypertension point to the importance of determining its pathogenesis to gain insights into its current and emerging management. Considering that the intricate control of BP is governed by a myriad of anatomical, molecular biological, biochemical, and physiological systems, multiple genes are likely to influence an individual's BP and susceptibility to develop hypertension. The long-term regulation of BP rests on renal and non-renal mechanisms. One renal mechanism relates to sodium transport. The impaired renal sodium handling in primary hypertension and salt sensitivity may be caused by aberrant counter-regulatory natriuretic and anti-natriuretic pathways. The sympathetic nervous and renin-angiotensin-aldosterone systems are examples of antinatriuretic pathways. An important counter-regulatory natriuretic pathway is afforded by the renal autocrine/paracrine dopamine system, aberrations of which are involved in the pathogenesis of hypertension, including that associated with obesity. We present updates on the complex interactions of these two systems with dietary salt intake in relation to obesity, insulin resistance, inflammation, and oxidative stress. We review how insults during pregnancy such as maternal and paternal malnutrition, glucocorticoid exposure, infection, placental insufficiency, and treatments during the neonatal period have long-lasting effects in the regulation of renal function and BP. Moreover, these effects have sex differences. There is a need for early diagnosis, frequent monitoring, and timely management due to increasing evidence of premature target organ damage. Large controlled studies are needed to evaluate the long-term consequences of the treatment of elevated BP during childhood, especially to establish the validity of the current definition and treatment of pediatric hypertension.
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Affiliation(s)
- Andrew C Tiu
- Division of Renal Diseases and Hypertension, The George Washington University School of Medicine and Health Sciences, 2300 I Street, N.W. Washington, DC, 20037, USA.
| | - Michael D Bishop
- Division of Renal Diseases and Hypertension, The George Washington University School of Medicine and Health Sciences, 2300 I Street, N.W. Washington, DC, 20037, USA
| | - Laureano D Asico
- Division of Renal Diseases and Hypertension, The George Washington University School of Medicine and Health Sciences, 2300 I Street, N.W. Washington, DC, 20037, USA
| | - Pedro A Jose
- Division of Renal Diseases and Hypertension, The George Washington University School of Medicine and Health Sciences, 2300 I Street, N.W. Washington, DC, 20037, USA
| | - Van Anthony M Villar
- Division of Renal Diseases and Hypertension, The George Washington University School of Medicine and Health Sciences, 2300 I Street, N.W. Washington, DC, 20037, USA
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Mansuri A, Elmaghrabi A, Legan SK, Gattineni J, Baum M. Transient Exposure of Enalapril Normalizes Prenatal Programming of Hypertension and Urinary Angiotensinogen Excretion. PLoS One 2015; 10:e0146183. [PMID: 26719973 PMCID: PMC4699824 DOI: 10.1371/journal.pone.0146183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/14/2015] [Indexed: 12/13/2022] Open
Abstract
Maternal low protein diet programs offspring to develop hypertension as adults. Transient exposure to angiotensin converting enzyme inhibitors or angiotensin II receptor blockers can result in improvement in hypertension. Male rats whose mothers received a low protein diet during the last half of pregnancy were given either vehicle, continuous enalapril (CE) in their drinking water or were given transient enalapril exposure (TE) after weaning at 21 days of age. The TE group had enalapril in their drinking water for 21 days starting from day 21 of life. All rats were studied at 6 months of age. Vehicle treated rats whose mothers were fed a low protein diet were hypertensive, had albuminuria, and demonstrated upregulation of the intrarenal renin-angiotensin system as evidenced by higher urinary angiotensinogen and urinary angiotensin II levels. In low protein rats both continuous and transient exposure to enalapril normalized blood pressure, urinary angiotensinogen and urinary angiotensin II levels at 6 months of age, but only continuous administration of enalapril decreased urinary albumin excretion. These data support the importance of the intrarenal renin-angiotensin system in mediating hypertension in programmed rats and transient exposure to enalapril can reprogram the hypertension and dysregulation of the intrarenal renin-angiotensin system.
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Affiliation(s)
- Asifhusen Mansuri
- Department of Pediatrics University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Ayah Elmaghrabi
- Department of Pediatrics University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Susan K. Legan
- Department of Pediatrics University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jyothsna Gattineni
- Department of Pediatrics University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michel Baum
- Department of Pediatrics University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Internal Medicine University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
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8
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Baum M. Luminal angiotensin II stimulates rat medullary thick ascending limb chloride transport in the presence of basolateral norepinephrine. Am J Physiol Renal Physiol 2015; 310:F294-9. [PMID: 26661654 DOI: 10.1152/ajprenal.00447.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/03/2015] [Indexed: 11/22/2022] Open
Abstract
Angiotensin II (ANG II) is secreted by the proximal tubule resulting in a luminal concentration that is 100- to 1,000-fold greater than that in the blood. Luminal ANG II has been shown to stimulate sodium transport in the proximal tubule and distal nephron. Surprisingly, luminal ANG II inhibits NaCl transport in the medullary thick ascending limb (mTAL), a nephron segment responsible for a significant amount of NaCl absorption from the glomerular ultrafiltrate. We confirmed that addition of 10(-8) M ANG II to the lumen inhibited mTAL chloride transport (220 ± 19 to 165 ± 25 pmol·mm(-1)·min(-1), P < 0.01) and examined whether an interaction with basolateral norepinephrine existed to simulate the in vivo condition of an innervated tubule. We found that in the presence of a 10(-6) M norepinephrine bath, luminal ANG II stimulated mTAL chloride transport from 298 ± 18 to 364 ± 42 pmol·mm(-1)·min(-1) (P < 0.05). Stimulation of chloride transport by luminal ANG II was also observed with 10(-3) M bath dibutyryl cAMP in the bathing solution and bath isoproterenol. A bath of 10(-5) H-89 blocked the stimulation of chloride transport by norepinephrine and prevented the effect of luminal ANG II to either stimulate or inhibit chloride transport. Bath phentolamine, an α-adrenergic agonist, also prevented the decrease in mTAL chloride transport by luminal ANG II. Thus luminal ANG II increases chloride transport with basolateral norepinephrine; an effect likely mediated by stimulation of cAMP. Alpha-1 adrenergic stimulation prevents the inhibition of chloride transport by luminal ANG II.
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Affiliation(s)
- Michel Baum
- Departments of Pediatrics and Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
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9
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Understanding the role of maternal diet on kidney development; an opportunity to improve cardiovascular and renal health for future generations. Nutrients 2015; 7:1881-905. [PMID: 25774605 PMCID: PMC4377888 DOI: 10.3390/nu7031881] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 01/08/2023] Open
Abstract
The leading causes of mortality and morbidity worldwide are cardiovascular disease (high blood pressure, high cholesterol and renal disease), cancer and diabetes. It is increasingly obvious that the development of these diseases encompasses complex interactions between adult lifestyle and genetic predisposition. Maternal malnutrition can influence the fetal and early life environment and pose a risk factor for the future development of adult diseases, most likely due to impaired organogenesis in the developing offspring. This then predisposes these offspring to cardiovascular disease and renal dysfunction in adulthood. Studies in experimental animals have further illustrated the significant impact maternal diet has on offspring health. Many studies report changes in kidney structure (a reduction in the number of nephrons in the kidney) in offspring of protein-deprived dams. Although the early studies suggested that increased blood pressure was also present in offspring of protein-restricted dams, this is not a universal finding and requires clarification. Importantly, to date, the literature offers little to no understanding of when in development these changes in kidney development occur, nor are the cellular and molecular mechanisms that drive these changes well characterised. Moreover, the mechanisms linking maternal nutrition and a suboptimal renal phenotype in offspring are yet to be discerned—one potential mechanism involves epigenetics. This review will focus on recent information on potential mechanisms by which maternal nutrition (focusing on malnutrition due to protein restriction, micronutrient restriction and excessive fat intake) influences kidney development and thereby function in later life.
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Zohdi V, Lim K, Pearson JT, Black MJ. Developmental programming of cardiovascular disease following intrauterine growth restriction: findings utilising a rat model of maternal protein restriction. Nutrients 2014; 7:119-52. [PMID: 25551250 PMCID: PMC4303830 DOI: 10.3390/nu7010119] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 12/08/2014] [Indexed: 12/11/2022] Open
Abstract
Over recent years, studies have demonstrated links between risk of cardiovascular disease in adulthood and adverse events that occurred very early in life during fetal development. The concept that there are embryonic and fetal adaptive responses to a sub-optimal intrauterine environment often brought about by poor maternal diet that result in permanent adverse consequences to life-long health is consistent with the definition of "programming". The purpose of this review is to provide an overview of the current knowledge of the effects of intrauterine growth restriction (IUGR) on long-term cardiac structure and function, with particular emphasis on the effects of maternal protein restriction. Much of our recent knowledge has been derived from animal models. We review the current literature of one of the most commonly used models of IUGR (maternal protein restriction in rats), in relation to birth weight and postnatal growth, blood pressure and cardiac structure and function. In doing so, we highlight the complexity of developmental programming, with regards to timing, degree of severity of the insult, genotype and the subsequent postnatal phenotype.
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Affiliation(s)
- Vladislava Zohdi
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia.
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker IDI Heart and Diabetes Institute, P.O. Box 6492 St Kilda Rd Central, Melbourne 8008, Australia.
| | - James T Pearson
- Department of Physiology, Monash University, Melbourne, VIC 3800, Australia.
| | - M Jane Black
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia.
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11
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Lozano G, Elmaghrabi A, Salley J, Siddique K, Gattineni J, Baum M. Effect of prenatal programming and postnatal rearing on glomerular filtration rate in adult rats. Am J Physiol Renal Physiol 2014; 308:F411-9. [PMID: 25537745 DOI: 10.1152/ajprenal.00593.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study examined whether a prenatal low-protein diet programs a decrease in glomerular filtration rate (GFR) and an increase in systolic blood pressure (BP). In addition, we examined whether altering the postnatal nutritional environment of nursing neonatal rats affected GFR and BP when rats were studied as adults. Pregnant rats were fed a normal (20%) protein diet or a low-protein diet (6%) during the last half of pregnancy until birth, when rats were fed a 20% protein diet. Mature adult rats from the prenatal low-protein group had systolic hypertension and a GFR of 0.38 ± 0.03 versus 0.57 ± 0.05 ml·min(-1)·100 g body wt(-1) in the 20% group (P < 0.01). In cross-fostering experiments, mothers continued on the same prenatal diet until weaning. Prenatal 6% protein rats cross-fostered to a 20% mother on day 1 of life had a GFR of 0.53 ± 0.05 ml·min(-1)·100 g body wt(-1), which was not different than the 20% group cross-fostered to a different 20% mother (0.45 ± 0.04 ml·min(-1)·100 g body wt(-1)). BP in the 6% to 20% group was comparable with the 20% to 20% group. Offspring of rats fed either 20% or 6% protein diets during pregnancy and cross-fostered to a 6% mother had elevated BP but a comparable GFR normalized to body weight as the 20% to 20% control group. Thus, a prenatal low-protein diet causes hypertension and a reduction in GFR in mature adult offspring, which can be modified by postnatal rearing.
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Affiliation(s)
- German Lozano
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Ayah Elmaghrabi
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Jordan Salley
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Khurrum Siddique
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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12
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Siddique K, Guzman GL, Gattineni J, Baum M. Effect of postnatal maternal protein intake on prenatal programming of hypertension. Reprod Sci 2014; 21:1499-507. [PMID: 24740990 DOI: 10.1177/1933719114530186] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This study examined whether postnatal maternal dietary protein deprivation during the time of nursing can program hypertension when the offspring are studied as adults. Rats were fed either a 6% or 20% protein diet during the second half of pregnancy and continued on the same diet while rats were nursing their pups. The neonates of all of the rats were cross-fostered to a different mother and studied as adults. Adult rats that had a normal prenatal environment but were reared by mothers fed a low-protein diet until weaning (20%-6%) were hypertensive, had a higher renal Na(+)-K(+)-2Cl(-) cotransporter (NKCC2) and Na(+)-Cl(-) cotransporter (NCC) protein abundance yet a comparable number of glomeruli, and had higher plasma renin and angiotensin II levels compared to control (20%-20%). Rats whose mothers were fed a 6% protein diet and cross-fostered to a different rat fed a 6% protein diet until weaning (6%-6%) were hypertensive, had elevated plasma renin and angiotensin II levels, and had a reduction in nephron number but had NKCC2 and NCC levels comparable to 20% to 20% offspring. The 6% to 20% had blood pressure and glomerular numbers comparable to 20% to 20% rats. The hypertension resulting from prenatal dietary protein deprivation can be normalized by improving the postnatal environment. Combined prenatal and postnatal maternal dietary protein deprivation and maternal dietary protein deprivation while nursing alone (20%-6%) results in hypertension, but the mechanism for the hypertension in these groups is different.
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Affiliation(s)
- Khurrum Siddique
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - German Lozano Guzman
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
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13
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DuBois BN, Pearson J, Mahmood T, Nguyen D, Thornburg K, Cherala G. Perinatal growth restriction decreases diuretic action of furosemide in adult rats. Eur J Pharmacol 2014; 728:39-47. [PMID: 24508521 DOI: 10.1016/j.ejphar.2014.01.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
Abstract
Perinatal growth restriction programs higher risk for chronic disease during adulthood via morphological and physiological changes in organ systems. Perinatal growth restriction is highly correlated with a decreased nephron number, altered renal function and subsequent hypertension. We hypothesize that such renal maladaptations result in altered pharmacologic patterns for life. Maternal protein restriction during gestation and lactation was used to induce perinatal growth restriction in the current study. The diuretic response of furosemide (2mg/kg single i.p. dose) in perinatally growth restricted rats during adulthood was investigated. Diuresis, natriuresis and renal excretion of furosemide were significantly reduced relative to controls, indicative of decreased efficacy. While a modest 12% decrease in diuresis was observed in males, females experienced 26% reduction. It is important to note that the baseline urine output and natriuresis were similar between treatment groups. The in vitro renal and hepatic metabolism of furosemide, the in vivo urinary excretion of the metabolite, and the expression of renal drug transporters were unaltered. Creatinine clearance was significantly reduced by 15% and 19% in perinatally growth restricted male and female rats, respectively. Further evidence of renal insufficiency was suggested by decreased uric acid clearance. Renal protein expression of sodium-potassium-chloride cotransporter, a pharmacodynamic target, was unaltered. In summary, perinatal growth restriction could permanently imprint pharmacokinetic processes affecting drug response.
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Affiliation(s)
- Barent N DuBois
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Jacob Pearson
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Tahir Mahmood
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Duc Nguyen
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA
| | - Kent Thornburg
- Center for Developmental Health, Oregon Health & Science University, Portland, OR 97239, USA; Department of Obstetrics & Gynecology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ganesh Cherala
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, 3303, SW Bond Avenue, CH12C, Portland, OR 97239, USA; Center for Developmental Health, Oregon Health & Science University, Portland, OR 97239, USA; Department of Obstetrics & Gynecology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
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14
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Lankadeva YR, Singh RR, Hilliard LM, Moritz KM, Denton KM. Impaired ability to modulate glomerular filtration rate in aged female sheep following fetal uninephrectomy. Physiol Rep 2014; 2:e00208. [PMID: 24744887 PMCID: PMC3967691 DOI: 10.1002/phy2.208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/05/2014] [Accepted: 01/07/2014] [Indexed: 02/05/2023] Open
Abstract
Fetal uninephrectomy (uni-x) results in hypertension at a later age in female than male sheep. We hypothesized that dysregulation of tubular sodium handling contributes to the reduced ability to regulate extracellular fluid (ECF) homeostasis in older females born with a congenital nephron deficit. Following renal excretory balance studies, the response to inhibition of the Na(+)K(+)2Cl(-) cotransporter with furosemide (0.5 mg/kg bolus + 1 mg/kg per hour, i.v) or vehicle treatment was examined in conscious 5-year-old female uni-x (n = 7) and sham (n = 7) sheep. Balance studies in meal-fed sheep demonstrated that while average 24 h sodium excretion over 6 days was not different between the groups, the daily variation in sodium excretion was significantly greater in uni-x compared to sham sheep (31 ± 4% vs. 12 ± 2%; P < 0.001). Basal plasma renin activity (PRA) and renal cortical cyclooxygenase-2 (COX-2) gene expression were lower in uni-x sheep (both, P < 0.01). The increases in glomerular filtration rate (GFR) and renal blood flow observed in sham sheep in response to furosemide were significantly attenuated in uni-x sheep (both P GROUP×TREAT < 0.05). However, fractional sodium excretion increased by a greater extent in the uni-x (4.4 ± 1.0%) as compared to the sham sheep (2.0 ± 0.4%; P GROUP×TIME < 0.05) in response to furosemide. In conclusion, fetal uni-x was associated with altered renal sodium handling and hypertension in aged females. The impaired ability to modulate PRA and GFR in the adults with a congenital nephron deficit may reduce the capacity of the kidney to respond to gains or losses in ECF to maintain a stable internal environment.
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Affiliation(s)
| | - Reetu R Singh
- Department of Physiology, Monash University, Victoria, Australia ; School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | | | - Karen M Moritz
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Kate M Denton
- Department of Physiology, Monash University, Victoria, Australia
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15
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Paixão AD, Alexander BT. How the kidney is impacted by the perinatal maternal environment to develop hypertension. Biol Reprod 2013; 89:144. [PMID: 24227755 DOI: 10.1095/biolreprod.113.111823] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Environmental conditions during perinatal development such as maternal undernutrition, maternal glucocorticoids, placental insufficiency, and maternal sodium overload can program changes in renal Na(+) excretion leading to hypertension. Experimental studies indicate that fetal exposure to an adverse maternal environment may reduce glomerular filtration rate by decreasing the surface area of the glomerular capillaries. Moreover, fetal responses to environmental insults during early life that contribute to the development of hypertension may include increased expression of tubular apical or basolateral membrane Na(+) transporters and increased production of renal superoxide leading to enhanced Na(+) reabsorption. This review will address the role of these potential renal mechanisms in the fetal programming of hypertension in experimental models induced by maternal undernutrition, fetal exposure to glucocorticoids, placental insufficiency, and maternal sodium overload in the rat.
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Affiliation(s)
- Ana D Paixão
- Department of Physiology and Pharmacology, Center of Biological Sciences, Federal University of Pernambuco, Recife, Brazil
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16
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Mizuno M, Lozano G, Siddique K, Baum M, Smith SA. Enalapril attenuates the exaggerated sympathetic response to physical stress in prenatally programmed hypertensive rats. Hypertension 2013; 63:324-9. [PMID: 24191284 DOI: 10.1161/hypertensionaha.113.02330] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Adulthood hypertension can be prenatally programmed by maternal dietary protein deprivation. We have shown that the sympathetically mediated pressor response to physical stress is exaggerated in prenatally programmed hypertensive (PPH) rats. The mechanisms underlying this abnormal responsiveness remain undetermined. The renin-angiotensin system is known to affect sympathetic nerve activity. Therefore, the purpose of this study was to determine whether inhibition of the renin-angiotensin system attenuates the enhanced sympathetic and pressor responses to physical stress in PPH rats. Changes in renal sympathetic nerve activity and blood pressure in response to hindlimb contraction, hindlimb stretch, and hindlimb intra-arterial capsaicin administration were assessed in control and PPH rats treated (from age 3 weeks) with either vehicle or the angiotensin-converting enzyme inhibitor enalapril. Conscious resting systolic arterial pressure was significantly greater in PPH rats (142±5 mm Hg) than in control (128±2 mm Hg) after vehicle treatment (P<0.05). Resting systolic pressure was reduced by enalapril treatment in PPH rats (125±2 mm Hg) but had no effect in control (128±2 mm Hg). The pressor and renal sympathetic responses to muscle contraction and stretch were significantly higher in decerebrate PPH rats than in decerebrate control in vehicle-treated groups. Responses to capsaicin were variable. Enalapril significantly attenuated the enhanced contraction-induced elevations in mean pressure (vehicle, 45±6 mm Hg; enalapril, 21±3 mm Hg) and renal sympathetic activity (vehicle, 175±22%; enalapril, 89±23%) in PPH rats. Its effects were similar on responses to stretch in PPH rats but were equivocal during capsaicin administration. The results suggest that the renin-angiotensin system contributes to the enhancement of the renal sympathetic and pressor responses to physical stress in PPH rats.
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Affiliation(s)
- Masaki Mizuno
- University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9174. ,
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17
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The fetal origins of hypertension: a systematic review and meta-analysis of the evidence from animal experiments of maternal undernutrition. J Hypertens 2013; 30:2255-67. [PMID: 22990358 DOI: 10.1097/hjh.0b013e3283588e0f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Numerous experiments in animals have been performed to investigate the effect of prenatal undernutrition on the development of hypertension in later life, with inconclusive results. We systematically reviewed animal studies examining the effects of maternal undernutrition on SBP, DBP, and mean arterial blood pressure (BP) in offspring. METHODS A search was performed in Medline and Embase to identify articles that reported on maternal undernutrition and hypertension in experimental animal studies. Summary estimates of the effect of undernutrition on SBP, DBP, and mean arterial BP were obtained through meta-analysis. RESULTS Of the 6151 articles identified, 194 were considered eligible after screening titles and abstracts. After detailed evaluation, 101 met the inclusion criteria and were included in the review. Both maternal general and protein undernutrition increased SBP [general undernutrition: 14.5 mmHg, 95% confidence interval (CI) 10.8-18.3; protein undernutrition: 18.9 mmHg, 95% CI 16.1-21.8] and mean arterial BP (general undernutrition: 5.0 mmHg, 95% CI 1.4-8.6; protein undernutrition: 10.5 mmHg, 95% CI 6.7-14.2). There was substantial heterogeneity in the results. DBP was increased by protein undernutrition (9.5 mmHg, 95% CI 2.6-16.3), whereas general undernutrition had no significant effect. CONCLUSION The results of this meta-analysis generally support the view that in animals, maternal undernutrition--both general and protein--results in increased SBP and mean arterial BP. DBP was only increased after protein undernutrition. The results depended strongly on the applied measurement technique and animal model.
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18
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Mizuno M, Siddique K, Baum M, Smith SA. Prenatal programming of hypertension induces sympathetic overactivity in response to physical stress. Hypertension 2012; 61:180-6. [PMID: 23150514 DOI: 10.1161/hypertensionaha.112.199356] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Small-for-gestational-age infants are known to develop hypertension in adulthood. This prenatal programming of hypertension (PPH) can result from several insults including maternal dietary protein deprivation, uteroplacental insufficiency, and prenatal administration of glucocorticoids. The mechanisms underlying the development of hypertension remain unclear although the sympathetic nervous system has been indirectly implicated. This study was designed to directly measure renal sympathetic nerve activity both at rest and during physical stress in an animal model of PPH. The adult male offspring of rats fed either a 6% (PPH) or 20% protein diet (control) were investigated. Conscious systolic blood pressure measured by tail cuff was significantly higher in PPH compared with control (140 ± 3 versus 128 ± 3 mm Hg; P<0.05). Baseline mean arterial pressure, heart rate, and renal sympathetic activity were not different between groups during isoflurane anesthesia or after decerebration. Physical stress was induced in decerebrate animals by activating the exercise pressor reflex during static muscle contraction. Stimulation of the exercise pressor reflex evoked significantly larger changes from baseline in mean arterial pressure (40 ± 7 versus 20 ± 4 mm Hg; P<0.05), heart rate (19 ± 3 versus 5 ± 1 bpm; P<0.05), and renal sympathetic activity (198 ± 29% versus 68 ± 14%; P<0.05) in PPH as compared with control. The data demonstrate that the sympathetic response to physical stress is markedly exaggerated in PPH and may play a significant role in the development of hypertension in adults born small for gestational age.
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Affiliation(s)
- Masaki Mizuno
- Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
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19
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Abstract
Epidemiological evidence suggests that exposure to an adverse environment in early life is associated with an increased risk of cardio-metabolic and behavioral disorders in adulthood, a phenomenon termed 'early life programming'. One major hypothesis for early life programming is fetal glucocorticoid overexposure. In animal studies, prenatal glucocorticoid excess as a consequence of maternal stress or through exogenous administration to the mother or fetus is associated with programming effects on cardiovascular and metabolic systems and on the brain. These effects can be transmitted to subsequent generations. Studies in humans provide some evidence that prenatal glucocorticoid exposure may exert similar programming effects on glucose/insulin homeostasis, blood pressure and neurodevelopment. The mechanisms by which glucocorticoids mediate these effects are unclear but may include a role for epigenetic modifications. This review discusses the evidence for glucocorticoid programming in animal models and in humans.
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Affiliation(s)
- Batbayar Khulan
- Endocrinology Unit, Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, Edinburgh, UK.
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20
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The effect of hypoxia-induced intrauterine growth restriction on renal artery function. J Dev Orig Health Dis 2012; 3:333-41. [DOI: 10.1017/s2040174412000268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
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.
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21
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Alwasel SH, Ashton N. Segmental sodium reabsorption by the renal tubule in prenatally programmed hypertension in the rat. Pediatr Nephrol 2012; 27:285-93. [PMID: 21863227 DOI: 10.1007/s00467-011-1976-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/05/2011] [Accepted: 07/05/2011] [Indexed: 10/17/2022]
Abstract
Hypertension and renal dysfunction can be programmed in the rat by prenatal exposure to a low-protein (LP) diet. Expression of the renal thick ascending limb (TAL) sodium transporter NKCC2 is up-regulated, which has been predicted to result in greater sodium reabsorption. However, we have shown that LP rats excrete more not less sodium. The aim of this study was to determine whether the increased abundance of sodium:potassium:chloride (Na(+):K(+):2Cl(-)) co-transporter (NKCC2) leads to enhanced sodium uptake by the TAL. Pregnant Wistar rats were fed a control (18%) or LP (9%) diet. Amiloride (AM), bendroflumethiazide (BF), and furosemide (FUR) were administered acutely to male offspring at 4 weeks of age. Fractional excretion of sodium (FE(Na)) was significantly greater in vehicle-infused LP rats (3.0 ± 0.3%) compared with controls (1.7 ± 0.5, P < 0.01). FE(Na) by the LP proximal tubule did not differ from controls, whereas FE(Na) by the distal tubule was significantly greater (P < 0.01). These differences were abolished by the administration of AM + BF (equivalent to the outflow from the TAL) and AM + BF + FUR (equivalent to the outflow from the proximal tubule), suggesting that the increase in NKCC2 expression was not functional. However, during acute salt loading, the LP rat pressure natriuresis curve was shifted rightward, implying that raised systemic blood pressure is required to match urinary sodium excretion with dietary intake. These data suggest that renal sodium handling is impaired in the LP rat but that this is not due to increased NKCC2 expression.
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Affiliation(s)
- Saleh H Alwasel
- Fetal Programming of Diseases Research Chair, College of Science, King Saud University, PO Box 2455, Riyadh, 11451, Saudi Arabia.
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22
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Abstract
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.
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23
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Cheng CJ, Lozano G, Baum M. Prenatal programming of rat cortical collecting tubule sodium transport. Am J Physiol Renal Physiol 2011; 302:F674-8. [PMID: 22189946 DOI: 10.1152/ajprenal.00633.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prenatal insults have been shown to lead to elevated blood pressure in offspring when they are studied as adults. Prenatal administration of dexamethasone and dietary protein deprivation have demonstrated that there is an increase in transporter abundance for a number of nephron segments but not the subunits of the epithelial sodium channel (ENaC) in the cortical collecting duct. Recent studies have shown that aldosterone is elevated in offspring of protein-deprived mothers when studied as adults, but the physiological importance of the increase in serum aldosterone is unknown. As an indirect measure of ENaC activity, we compared the natriuretic response to benzamil in offspring of mothers who ate a low-protein diet (6%) with those who ate a normal diet (20%) for the last half of pregnancy. The natriuretic response to benzamil was greater in the 6% group (821.1 ± 161.0 μmol/24 h) compared with the 20% group (279.1 ± 137.0 μmol/24 h), consistent with greater ENaC activity in vivo (P < 0.05). In this study, we also directly studied cortical collecting tubule function from adult rats using in vitro microperfusion. There was no difference in basal or vasopressin-stimulated osmotic water permeability. However, while cortical collecting ducts of adult offspring whose mothers ate a 20% protein diet had no sodium transport (-1.9 ± 3.1 pmol·mm(-1)·min(-1)), the offspring of rats that ate a 6% protein diet during the last half of pregnancy had a net sodium flux of 10.7 ± 2.6 pmol·mm(-1)·min(-1) (P = 0.01) in tubules perfused in vitro. Sodium transport was measured using ion-selective electrodes, a novel technique allowing measurement of sodium in nanoliter quantities of fluid. Thus we directly demonstrate that there is prenatal programming of cortical collecting duct sodium transport.
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Affiliation(s)
- Chih-Jen Cheng
- Dept. of Pediatrics, U.T. Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9063, USA
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24
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Habib S, Zhang Q, Baum M. Prenatal programming of hypertension in the rat: effect of postnatal rearing. NEPHRON EXTRA 2011; 1:157-65. [PMID: 22470389 PMCID: PMC3290837 DOI: 10.1159/000333477] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Background/Aims Dietary protein deprivation during pregnancy causes hypertension in offspring when they become adults. This study examined if postnatal rearing had an effect on blood pressure and glomerular number in male rats whose mothers were fed either a control diet or a low protein diet. Methods Neonates were cross fostered at 1 day of age to a different mother. After birth, all nursing and weaned rats were fed a control diet. Blood pressure and glomerular number were measured in adult offspring. Results Control rats cross fostered to another control mother had a lower blood pressure than low protein rats cross fostered to another low protein mother (133 ± 4 vs. 151 ± 4 mm Hg, p < 0.05) and a greater number of glomeruli (28,388 ± 989 vs. 25,045 ± 851, p < 0.05). Fostering pups from the 20% group to mothers that were fed a 6% diet during pregnancy did not cause hypertension or a reduction in the number of glomeruli. However, fostering the 6% group on to mothers that were fed a 20% protein diet during pregnancy resulted in normalization of the blood pressure and number of glomeruli. Conclusion The hypertension and reduced glomerular number resulting from prenatal dietary protein deprivation can be normalized by improving the postnatal environment.
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Affiliation(s)
- Sabeen Habib
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, Tex., USA
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25
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Abstract
Epidemiologic studies now strongly support the hypothesis, proposed over two decades ago, that developmental programming of the kidney impacts an individual's risk for hypertension and renal disease in later life. Low birth weight is the strongest current clinical surrogate marker for an adverse intrauterine environment and, based on animal and human studies, is associated with a low nephron number. Other clinical correlates of low nephron number include female gender, short adult stature, small kidney size, and prematurity. Low nephron number in Caucasian and Australian Aboriginal subjects has been shown to be associated with higher blood pressures, and, conversely, hypertension is less prevalent in individuals with higher nephron numbers. In addition to nephron number, other programmed factors associated with the increased risk of hypertension include salt sensitivity, altered expression of renal sodium transporters, altered vascular reactivity, and sympathetic nervous system overactivity. Glomerular volume is universally found to vary inversely with nephron number, suggesting a degree of compensatory hypertrophy and hyperfunction in the setting of a low nephron number. This adaptation may become overwhelmed in the setting of superimposed renal insults, e.g. diabetes mellitus or rapid catch-up growth, leading to the vicious cycle of on-going hyperfiltration, proteinuria, nephron loss and progressive renal functional decline. Many millions of babies are born with low birth weight every year, and hypertension and renal disease prevalences are increasing around the globe. At present, little can be done clinically to augment nephron number; therefore adequate prenatal care and careful postnatal nutrition are crucial to optimize an individual's nephron number during development and potentially to stem the tide of the growing cardiovascular and renal disease epidemics worldwide.
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Affiliation(s)
- Valerie A. Luyckx
- Associate Professor, Division of Nephrology, University of Alberta, Edmonton, Alberta, Canada
- To whom correspondence should be addressed. E-mail:
| | - Khuloud Shukha
- Internal Medicine Resident, Mount Auburn Hospital, Cambridge, MA, USA; and
| | - Barry M. Brenner
- Samuel A. Levine Distinguished Professor of Medicine Renal Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Metabolic programming during lactation stimulates renal Na+ transport in the adult offspring due to an early impact on local angiotensin II pathways. PLoS One 2011; 6:e21232. [PMID: 21747933 PMCID: PMC3128598 DOI: 10.1371/journal.pone.0021232] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 05/24/2011] [Indexed: 12/21/2022] Open
Abstract
Background Several studies have correlated perinatal malnutrition with diseases in adulthood, giving support to the programming hypothesis. In this study, the effects of maternal undernutrition during lactation on renal Na+-transporters and on the local angiotensin II (Ang II) signaling cascade in rats were investigated. Methodology/Principal Findings Female rats received a hypoproteic diet (8% protein) throughout lactation. Control and programmed offspring consumed a diet containing 20% protein after weaning. Programming caused a decrease in the number of nephrons (35%), in the area of the Bowman's capsule (30%) and the capillary tuft (30%), and increased collagen deposition in the cortex and medulla (by 175% and 700%, respectively). In programmed rats the expression of (Na++K+)ATPase in proximal tubules increased by 40%, but its activity was doubled owing to a threefold increase in affinity for K+. Programming doubled the ouabain-insensitive Na+-ATPase activity with loss of its physiological response to Ang II, increased the expression of AT1 and decreased the expression of AT2 receptors), and caused a pronounced inhibition (90%) of protein kinase C activity with decrease in the expression of the α (24%) and ε (13%) isoforms. Activity and expression of cyclic AMP-dependent protein kinase decreased in the same proportion as the AT2 receptors (30%). In vivo studies at 60 days revealed an increased glomerular filtration rate (GFR) (70%), increased Na+ excretion (80%) and intense proteinuria (increase of 400% in protein excretion). Programmed rats, which had normal arterial pressure at 60 days, became hypertensive by 150 days. Conclusions/Significance Maternal protein restriction during lactation results in alterations in GFR, renal Na+ handling and in components of the Ang II-linked regulatory pathway of renal Na+ reabsorption. At the molecular level, they provide a framework for understanding how metabolic programming of renal mechanisms contributes to the onset of hypertension in adulthood.
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27
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Habib S, Gattineni J, Twombley K, Baum M. Evidence that prenatal programming of hypertension by dietary protein deprivation is mediated by fetal glucocorticoid exposure. Am J Hypertens 2011; 24:96-101. [PMID: 20725051 DOI: 10.1038/ajh.2010.177] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Prenatal programming by maternal dietary protein deprivation and prenatal dexamethasone result in a reduction in nephron number and hypertension when the offspring are studied as adults. METHODS To determine whether prenatal dietary protein deprivation results in a reduction in nephron number and hypertension in offspring by exposure to maternal glucocorticoids, we administered metyrapone to rats fed either a 6% or 20% protein diet to inhibit glucocorticoid production and compared the offspring to rats that were the product of mothers fed either a 6% or 20% protein diet during the last half of pregnancy. RESULTS Male offspring from the 6% group had elevated systolic blood pressure (149 ± 2 vs. 130 ± 5 mm Hg, P < 0.05) and a reduction in glomeruli compared to the 20% group (22,111 ± 627 vs. 29,666 ± 654 glomeruli/kidney, P < 0.001). Maternal metyrapone administration did not affect the blood pressure in the 20% group but ameliorated the increase in blood pressure in the 6% male group to values comparable to the 20% control group (138 ± 6 vs. 130 ± 5 mm Hg). Male offspring of the 6% group that received metyrapone had an increase in the number of glomeruli compared to the vehicle-treated 6% group (26,780 ± 377 vs. 22,111 ± 627 glomeruli/kidney, P < 0.001), but less glomeruli compared to the 20% protein control group (26,780 ± 377 vs. 29,666 ± 654 glomeruli/kidney, P = 0.01). CONCLUSIONS The reduction in nephron number and hypertension induced by maternal protein deprivation in male offspring is ameliorated by inhibition of glucocorticoid production.
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28
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Abstract
Development of the kidney can be altered in utero in response to a suboptimal environment. The intrarenal factors that have been most well characterized as being sensitive to programming events are kidney mass/nephron endowment, the renin-angiotensin system, tubular sodium handling, and the renal sympathetic nerves. Newborns that have been subjected to an adverse intrauterine environment may thus begin life at a distinct disadvantage, in terms of renal function, at a time when the kidney must take over the primary role for extracellular fluid homeostasis from the placenta. A poor beginning, causing renal programming, has been linked to increased risk of hypertension and renal disease in adulthood. However, although a cause for concern, increasingly, evidence demonstrates that renal programming is not a fait accompli in terms of future cardiovascular and renal disease. A greater understanding of postnatal renal maturation and the impact of secondary factors (genes, sex, diet, stress, and disease) on this process is required to predict which babies are at risk of increased cardiovascular and renal disease as adults and to be able to devise preventative measures.
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Affiliation(s)
- Michelle M Kett
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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Augustyniak RA, Singh K, Zeldes D, Singh M, Rossi NF. Maternal protein restriction leads to hyperresponsiveness to stress and salt-sensitive hypertension in male offspring. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1375-82. [PMID: 20200128 PMCID: PMC2867525 DOI: 10.1152/ajpregu.00848.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 02/27/2010] [Indexed: 01/06/2023]
Abstract
Low birth weight humans often exhibit hypertension during adulthood. Studying the offspring of rat dams fed a maternal low-protein diet is one model frequently used to study the mechanisms of low birth weight-related hypertension. It remains unclear whether this model replicates key clinical findings of hypertension and increased blood pressure responsiveness to stress or high-salt diet. We measured blood pressure via radiotelemetry in 13-wk-old male offspring of maternal normal- and low-protein dams. Neither group exhibited hypertension at baseline; however, 1 h of restraint was accompanied by a significantly greater blood pressure response in low-protein compared with normal-protein offspring. To enhance the effect of a high-salt diet on blood pressure, normal- and low-protein offspring underwent right uninephrectomy, while controls underwent sham surgery. After 5 weeks on a high-salt diet (4% NaCl), mean arterial pressure in the Low-Protein+Sham offspring was elevated by 6 +/- 2 mmHg (P < 0.05 vs. baseline), while it remained unchanged in the normal-protein offspring. In the two uninephrectomized groups, blood pressure increased further, but was of similar magnitude. Glomerular filtration rate in the low-protein uninephrectomized offspring was 50% less than that in normal-protein offspring with intact kidneys. These data indicate that, while male low-protein offspring are not hypertensive during young adulthood, their blood pressure is hyperresponsive to restraint stress and is salt sensitive, and their glomerular filtration rate is more sensitive to hypertension-causing insults. Collectively, these may predispose for the development of hypertension later in life.
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Dagan A, Gattineni J, Habib S, Baum M. Effect of prenatal dexamethasone on postnatal serum and urinary angiotensin II levels. Am J Hypertens 2010; 23:420-4. [PMID: 20075846 DOI: 10.1038/ajh.2009.274] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Prenatal programming of hypertension has been described in humans and in animal models that receive a prenatal insult, but the mechanism for the increase in blood pressure remains elusive. METHODS In male rats whose mothers received dexamethasone between days 15 and 18 of gestation systemic and urinary levels of angiotensin II were measured to determine whether angiotensin II was a potential factor for the generation (4 weeks of age) or maintenance (8 weeks of age) of hypertension. RESULTS A group 4- and 8-week-old male rats that were the product of a pregnancy where the mother received prenatal dexamethasone between days 15 and 18 of gestation had comparable plasma renin and angiotensin II levels to the offspring of vehicle-treated controls. Renal angiotensin II levels were not different at 4 and 8 weeks of age between the controls and the prenatal dexamethasone group. Urine angiotensin II/Creatinine levels, a reflection of filtered and renally generated and secreted angiotensin II, were higher at both 4 and 8 weeks of age in male rats that received prenatal dexamethasone compared to controls. CONCLUSIONS The high-urine angiotensin II levels in prehypertensive and hypertensive rats that were the product of mothers that received dexamethasone compared to vehicle suggest that luminal angiotensin II may play a role in the generation and maintenance of hypertension in this model of prenatal programming.
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Baum M. Effect of catecholamines on rat medullary thick ascending limb chloride transport: interaction with angiotensin II. Am J Physiol Regul Integr Comp Physiol 2010; 298:R954-8. [PMID: 20147605 DOI: 10.1152/ajpregu.00758.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that in proximal and distal tubule nephron segments, peritubular ANG II stimulates sodium chloride transport. However, ANG II inhibits chloride transport in the medullary thick ascending limb (mTAL). Because ANG II and catecholamines are both stimulated by a decrease in extracellular fluid volume, the purpose of this study was to examine whether there was an interaction between ANG II and catecholamines to mitigate the inhibition in chloride transport by ANG II. In isolated perfused rat mTAL, 10(-8) M bath ANG II inhibited transport (from a basal transport rate of 165.6 +/- 58.8 to 58.8 +/- 29.4 pmol.mm(-1).min(-1); P < 0.01). Bath norepinephrine stimulated chloride transport (from a basal transport rate of 298.1 +/- 31.7 to 425.2 +/- 45.8 pmol.mm(-1).min(-1); P < 0.05) and completely prevented the inhibition in chloride transport by ANG II. The stimulation of chloride transport by norepinephrine was mediated entirely by its beta-adrenergic effect; however, both the beta- and alpha-adrenergic agonists isoproterenol and phenylephrine prevent the ANG II-mediated inhibition in chloride transport. In the presence of 10(-5) M propranolol, the effect of norepinephrine to prevent the inhibition of chloride transport by ANG II was still present. These data are consistent with an interaction of both alpha- and beta-catecholamines and ANG II on net chloride transport in the mTAL.
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Affiliation(s)
- Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9063, USA.
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Baum M. Role of the kidney in the prenatal and early postnatal programming of hypertension. Am J Physiol Renal Physiol 2009; 298:F235-47. [PMID: 19794108 DOI: 10.1152/ajprenal.00288.2009] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Epidemiologic studies from several different populations have demonstrated that prenatal insults, which adversely affect fetal growth, result in an increased incidence of hypertension when the offspring reaches adulthood. It is now becoming evident that low-birth-weight infants are also at increased risk for chronic kidney disease. To determine how prenatal insults result in hypertension and chronic kidney disease, investigators have used animal models that mimic the adverse events that occur in pregnant women, such as dietary protein or total caloric deprivation, uteroplacental insufficiency, and prenatal administration of glucocorticoids. This review examines the role of the kidney in generating and maintaining an increase in blood pressure in these animal models. This review also discusses how early postnatal adverse events may have repercussions in later life. Causes for the increase in blood pressure by perinatal insults are likely multifactorial and involve a reduction in nephron number, dysregulation of the systemic and intrarenal renin-angiotensin system, increased renal sympathetic nerve activity, and increased tubular sodium transport. Understanding the mechanism for the increase in blood pressure and renal injury resulting from prenatal insults may lead to therapies that prevent hypertension and the development of chronic kidney and cardiovascular disease.
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Affiliation(s)
- Michel Baum
- Department of Pediatrics and Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9063, USA.
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