1
|
McArdle Z, Singh R, Bielefeldt-Ohmann H, Moritz K, Schreuder M, Denton K. Brief Early Life Angiotensin Converting Enzyme Inhibition Offers Reno-Protection in Sheep with a Solitary Functioning Kidney at 8 Months of Age. J Am Soc Nephrol 2022; 33:1341-1356. [PMID: 35351818 PMCID: PMC9257814 DOI: 10.1681/asn.2021111534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/18/2022] [Indexed: 11/03/2022] Open
Abstract
Background: Children born with a solitary functioning kidney (SFK) are predisposed to develop hypertension and kidney injury. Glomerular hyperfiltration and hypertrophy contribute to the pathophysiology of kidney injury. Angiotensin converting enzyme inhibitors (ACEi) can mitigate hyperfiltration and may be therapeutically beneficial in reducing progression of kidney injury in SFK. Methods: SFK was induced in male sheep fetuses at 100 days gestation (term=150 day). Between 4-8 weeks of age, SFK lambs received enalapril (SFK+ACEi; 0.5mg/kg/day, once daily, orally) or vehicle (SFK). At 8 months we examined whether SFK+ACEi reduced elevation in blood pressure (BP) and improved basal kidney function, renal functional reserve (RFR; glomerular filtration rate (GFR) response to combined amino acid and dopamine infusion), GFR response to nitric oxide synthase (NOS) inhibition and basal nitric oxide (NO) bioavailability (basal urinary total nitrate+nitrite (NOx)). Results: SFK+ACEi prevented albuminuria, resulted in lower basal GFR (16%), higher renal blood flow (~22%), and lower filtration fraction ( 35%), but similar BP compared to ~ vehicle-treated SFK sheep. Together with greater recruitment of RFR (~14%) in SFK+ACEi animals than SFK, this indicates reduction in glomerular hyperfiltration-mediated kidney dysfunction. During NOS inhibition, the decrease in GFR ( 14%) was greater among SFK+ACEi than among SFK animals. Increased ( 85%) basal urinary total NOx in SFK+ACEi animals compared to SFK indicates elevated NO bioavailability likely contributing to improvements in kidney function and prevention of albuminuria. Conclusions: Brief and early ACEi in SFK is associated with reduced glomerular hyperfiltration-mediated kidney disease up to 8 months of age in a sheep model.
Collapse
Affiliation(s)
- Zoe McArdle
- Z McArdle, Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Reetu Singh
- R Singh, Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Helle Bielefeldt-Ohmann
- H Bielefeldt-Ohmann, School of Veterinary Science, The University of Queensland, Gatton, Australia
| | - Karen Moritz
- K Moritz, Child Health Research Centre and School of Biomedical Sciences, The University of Queensland, Saint Lucia, Australia
| | - Michiel Schreuder
- M Schreuder, Department of Pediatric Nephrology , Amalia Children's Hospital, Nijmegen, Netherlands
| | - Kate Denton
- K Denton, Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| |
Collapse
|
2
|
Fanni D, Gerosa C, Vinci L, Ambu R, Dessì A, Eyken PV, Fanos V, Faa G. Interstitial stromal progenitors during kidney development: here, there and everywhere. J Matern Fetal Neonatal Med 2016; 29:3815-20. [PMID: 26866875 DOI: 10.3109/14767058.2016.1147553] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In recent years, the renal interstitium has been identified as the site of multiple cell types, giving rise to multiple contiguous cellular networks with multiple fundamental structural and functional roles. Few studies have been carried out on the morphological and functional properties of the stromal/interstitial renal cells during the intrauterine life. This work was aimed at reviewing the peculiar features of renal interstitial stem/progenitor cells involved in kidney development. The origin of the renal interstitial progenitor cells remains unknown. During kidney development, besides the Six2 + cells of the cap mesenchyme, a self-renewing progenitor population, characterized by the expression of Foxd1, represents the first actor of the non-nephrogenic lineage. Foxd1 + interstitial progenitors originate the cortical and the renal medullary interstitial progenitors. Here, the most important stromal/interstitial compartments present in the developing human kidney will be analyzed: capsular stromal cells, cortical interstitial cells, medullary interstitial cells, the interstitium inside the renal stem cell niche, Hilar interstitial cells and Ureteric interstitial cells. Data reported here indicate that the different interstitial compartments of the developing kidney are formed by different cell types that characterize the different renal areas. Further studies are needed to better characterize the different pools of renal interstitial progenitors and their role in human nephrogenesis.
Collapse
Affiliation(s)
- Daniela Fanni
- a Division of Pathology , Department of Surgical Sciences, University of Cagliari , Cagliari , Italy
| | - Clara Gerosa
- a Division of Pathology , Department of Surgical Sciences, University of Cagliari , Cagliari , Italy
| | - Laura Vinci
- a Division of Pathology , Department of Surgical Sciences, University of Cagliari , Cagliari , Italy
| | - Rossano Ambu
- a Division of Pathology , Department of Surgical Sciences, University of Cagliari , Cagliari , Italy
| | - Angelica Dessì
- b Department of Surgical Sciences , NICU Center and Puericulture Institute and Neonatal Section, University of Cagliari , Cagliari , Italy , and
| | - Peter Van Eyken
- c Department of Pathology , University Hospitals, KU , Leuven , Belgium
| | - Vassilios Fanos
- b Department of Surgical Sciences , NICU Center and Puericulture Institute and Neonatal Section, University of Cagliari , Cagliari , Italy , and
| | - Gavino Faa
- a Division of Pathology , Department of Surgical Sciences, University of Cagliari , Cagliari , Italy
| |
Collapse
|
3
|
|
4
|
Jiang Y, Jiang T, Ouyang J, Zhou Q, Liang Y, Cui Y, Chen P, Huang B. Cell atavistic transition: Paired box 2 re-expression occurs in mature tubular epithelial cells during acute kidney injury and is regulated by Angiotensin II. PLoS One 2014; 9:e93563. [PMID: 24710423 PMCID: PMC3977930 DOI: 10.1371/journal.pone.0093563] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 03/06/2014] [Indexed: 12/20/2022] Open
Abstract
The regeneration of tubular epithelial cells (TECs) after acute kidney injury (AKI) is crucial for the recovery of renal structure and function. The mechanism by which quiescent TECs re-obtain a potential to regenerate remains unknown. In this study, we observed a transient re-expression of embryonic gene Paired box 2 (Pax2) in adult rat TECs in vivo during ischemia-reperfusion induced AKI and most Pax2 positive TECs co-expressed kidney injury molecule-1 (KIM-1), a tubular injury marker. The re-expression of Pax2 was accompanied by increased levels of intrarenal Angiotensin II, which is a crucial injury factor of AKI. Furthermore, we also found a temporary re-expression of Pax2 in NRK-52E cells under the stimulation of Angiotensin II. This stimulatory effect could be blocked by PD123319 (Angiotensin II type 2 receptor (AT2R) inhibitor) and AG490 (Janus Kinase 2 (JAK2) inhibitor). As Pax2 is essential for the phenotypic conversion from mesenchymal stem cells to TECs during kidney development, we proposed that the re-expression of Pax2 in mature TECs may be an indicator of “atavistic” transition which mimics but reverses the processes of development of TECs. This could be proved by that a progenitor marker, CD24, was also found to be transiently expressed shortly after the expression of Pax2 in NRK-52E cells stimulated with Angiotensin II. The expression of CD24 was also suppressed by PD123319 and AG490. Moreover, knockdown of Pax2 by RNA interference could significantly reduce the expression of CD24 in NRK-52E cells stimulated with Angiotension II. Those findings suggest that mature TECs can trans-differentiate into progenitor-like cells by “atavistic transition”, which may participate in the recovery of tissue structure and Pax2 may play a pivotal role in this process. That might have important implications for further understanding of tubular regeneration after injury.
Collapse
Affiliation(s)
- Yushen Jiang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Tang Jiang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- * E-mail:
| | - Juan Ouyang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Qingsong Zhou
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yanlan Liang
- Department of Laboratory Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yingpeng Cui
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Peisong Chen
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| |
Collapse
|
5
|
Granado M, Fernández N, Monge L, Figueras JC, Carreño-Tarragona G, Amor S, García-Villalón AL. Effects of coronary ischemia-reperfusion in a rat model of early overnutrition. Role of angiotensin receptors. PLoS One 2013; 8:e54984. [PMID: 23383303 PMCID: PMC3562319 DOI: 10.1371/journal.pone.0054984] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/18/2012] [Indexed: 11/19/2022] Open
Abstract
Background Obesity during childhood has dramatically increased worldwide in the last decades. Environmental factors acting early in life, including nutrition, play an important role in the pathogenesis of obesity and cardiovascular diseases in adulthood. Aims To analyze the effects of early overfeeding on the heart and coronary circulation, the effect of ischemia-reperfusion (I/R) and the role of the renin-angiotensin system (RAS) were studied in isolated hearts from control and overfed rats during lactation. Methods and Results On the day of birth litters were adjusted to twelve pups per mother (control) or to three pups per mother (overfed). At weaning (21 days) the rats were killed and the heart perfused in a Langendorff system and subjected to 30 min of ischemia followed by 15 min of reperfusion. The contractility (left developed intraventricular pressure) was lower in the hearts from overfed rats, and was reduced by I/R in hearts from control but not from overfed rats. I/R also reduced the coronary vasoconstriction to angiotensin II more in hearts from control than from overfed rats, and the vasodilatation to bradykinin similarly in both experimental groups. The expression of both angiotensin AGTRa and AGTR2 receptors was increased in the myocardium of overfed rats, and I/R increased the expression of both receptors in control rats but reduced it in overfed rats. The expression of apoptotic and antiapoptotic markers was increased in hearts of overfed rats compared with control, and further increased by I/R. Conclusions These results suggest that both overfeeding and I/R impair cardiac and coronary function due, at least in part, to activation of the angiotensin pathway. However, overfeeding may reduce the impairment of ventricular contractility by I/R.
Collapse
Affiliation(s)
- Miriam Granado
- Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
- CIBER Fisiopatología de Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Nuria Fernández
- Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luis Monge
- Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Carlos Figueras
- Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Sara Amor
- Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | | |
Collapse
|
6
|
Capelari DN, Sánchez SI, Ortega HH, Ciuffo GM, Fuentes LB. Effects of maternal captopril treatment during late pregnancy on neonatal lung development in rats. ACTA ACUST UNITED AC 2012; 177:97-106. [DOI: 10.1016/j.regpep.2012.05.092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 03/10/2012] [Accepted: 05/05/2012] [Indexed: 11/28/2022]
|
7
|
Gao J, Chao J, Parbhu KJK, Yu L, Xiao L, Gao F, Gao L. Ontogeny of angiotensin type 2 and type 1 receptor expression in mice. J Renin Angiotensin Aldosterone Syst 2012; 13:341-52. [PMID: 22526820 DOI: 10.1177/1470320312443720] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In the current experiment, we determined angiotensin type 2 receptor (AT2R) and angiotensin type 1 receptor (AT1R) protein expression by western blot analysis in developing normal mice. The results indicate that: (1) in all detected brain regions and in the spinal cord, adult mice exhibited significantly higher AT2R expression and lower AT1R expression in total protein extracts compared to fetuses and neonates; (2) other major organs, including heart, lung, liver and kidney, exhibited the same expression pattern as the brain and spinal cord; (3) reciprocal changes in AT2R and AT1R expression were found in the total protein extracts from the brainstems of mice from one-day prenatal to six weeks of age, and there was a negative correlation between AT2R and AT1R protein expression; (4) in both membrane and cytosolic fractions from the brainstem, adult mice exhibited higher AT2R and lower AT1R expression than did fetuses and neonates; and (5) in the brainstem, there were no significant differences in AT2R and AT1R messenger RNA (mRNA) levels among fetal, neonatal and adult mice. The above results reconfirmed our previous finding in rats that adult animals have higher AT2R and lower AT1R expression compared to fetuses and neonates. These data imply an involvement of AT1R in fetal development and of AT2R in adult function.
Collapse
Affiliation(s)
- Juan Gao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Rodriguez DL, de Mesquita FC, Attolini D, de Borba BS, Scherer PS, Almeida PH, da Costa VL, Scherer BS, Schmitt VM, de Oliveira JR, Donadio MVF. Evaluation of the brain and kidney renin-angiotensin system and oxidative stress in neonatal handled rats. Dev Psychobiol 2011; 54:706-13. [PMID: 22127847 DOI: 10.1002/dev.20620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022]
Abstract
The aim of this study was to test the hypothesis that the renin-angiotensin system (RAS) components, as well as the oxidative stress system, would respond to early environmental changes. Thus, we have evaluated the effects of neonatal handling on both brain and kidney RAS and oxidative stress. Pups were divided into two groups: nonhandled and handled. The procedure consisted of handling them for 1 min/day in the first 10 days of life. On days 1, 5, and 10, animals were killed by decapitation. Blood samples were collected and the brain and kidneys were removed. Renin, AT(1), and AT(2) mRNA expression were evaluated through RT-PCR. Angiotensin II (ANG II) serum concentration was also measured. An increased ANG II concentration, brain and kidney AT(2) mRNA expression were demonstrated. The kidney mRNA AT(1) expression was decreased. There was also a kidney lipid peroxidation increase and a brain superoxide dismutase and catalase decrease. In conclusion, handling in the neonatal period induces the activation of the angiotensinergic system, as well as modulates its mRNA receptor expression. The oxidative stress balance system seems not to be involved.
Collapse
Affiliation(s)
- Daniela L Rodriguez
- Faculdade de Biociências e Laboratório de Pesquisa em Biofísica Celular e Inflamação, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre/RS, Brazil
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Stridh S, Kerjaschki D, Chen Y, Rügheimer L, Astrand ABM, Johnsson C, Friberg P, Olerud J, Palm F, Takahashi T, Ikegami-Kawai M, Hansell P. Angiotensin converting enzyme inhibition blocks interstitial hyaluronan dissipation in the neonatal rat kidney via hyaluronan synthase 2 and hyaluronidase 1. Matrix Biol 2010; 30:62-9. [PMID: 20933085 DOI: 10.1016/j.matbio.2010.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 09/01/2010] [Accepted: 09/29/2010] [Indexed: 11/18/2022]
Abstract
A functional renin-angiotensin system (RAS) is required for normal kidney development. Neonatal inhibition of the RAS in rats results in long-term pathological renal phenotype and causes hyaluronan (HA), which is involved in morphogenesis and inflammation, to accumulate. To elucidate the mechanisms, intrarenal HA content was followed during neonatal completion of nephrogenesis with or without angiotensin converting enzyme inhibition (ACEI) together with mRNA expression of hyaluronan synthases (HAS), hyaluronidases (Hyal), urinary hyaluronidase activity and cortical lymphatic vessels, which facilitate the drainage of HA from the tissue. In 6-8days old control rats cortical HA content was high and reduced by 93% on days 10-21, reaching adult low levels. Medullary HA content was high on days 6-8 and then reduced by 85% to 12-fold above cortical levels at day 21. In neonatally ACEI-treated rats the reduction in HA was abolished. Temporal expression of HAS2 corresponded with the reduction in HA content in the normal kidney. In ACEI-treated animals cortical HAS2 remained twice the expression of controls. Medullary Hyal1 increased in controls but decreased in ACEI-treated animals. Urine hyaluronidase activity decreased with time in control animals while in ACEI-treated animals it was initially 50% lower and did not change over time. Cells expressing the lymphatic endothelial mucoprotein podoplanin in ACEI-treated animals were increased 18-fold compared to controls suggesting compensation. In conclusion, the high renal HA content is rapidly reduced due to reduced HAS2 and increased Hyal1 mRNA expressions. Normal angiotensin II function is crucial for inducing these changes. Due to the extreme water-attracting and pro-inflammatory properties of HA, accumulation in the neonatally ACEI-treated kidneys may partly explain the pathological renal phenotype of the adult kidney, which include reduced urinary concentration ability and tubulointerstitial inflammation.
Collapse
Affiliation(s)
- S Stridh
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Thrift AG, Srikanth V, Fitzgerald SM, Kalyanram K, Kartik K, Hoppe CC, Walker KZ, Evans RG. Potential roles of high salt intake and maternal malnutrition in the development of hypertension in disadvantaged populations. Clin Exp Pharmacol Physiol 2009; 37:e78-90. [PMID: 19650789 DOI: 10.1111/j.1440-1681.2009.05266.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
1. It has been argued that all major risk factors for cardiovascular disease have been identified. Yet, epidemiological studies undertaken to identify risk factors have largely focused on populations in developed nations or on the urban or relatively affluent rural populations of developing countries. Poor rural populations are seldom studied. 2. Somewhat different risk factors may operate in poor rural populations. Evidence for this is provided by the finding that, in disadvantaged rural India, the prevalence of hypertension is greater than would be expected based on established risk factors in these populations. One risk factor to be considered is a poor intrauterine environment. 3. In animals, maternal macro- and micronutrient malnutrition can lead to reduced nephron endowment. Nephron deficiency, in turn, can render blood pressure salt sensitive. The combination of nephron deficiency and excessive salt intake will predispose to hypertension. 4. Human malnutrition may have similar effects, particularly in regions of the world where malnutrition is endemic and where women are disadvantaged by existing social practices. 5. Moreover, high salt intake is endemic in many parts of Asia, including India. Therefore, we propose that maternal malnutrition (leading to reduced nephron endowment), when combined with excessive salt intake postnatally, will account, at least in part, for the unexpectedly high prevalence of hypertension in disadvantaged rural communities in India and elsewhere.
Collapse
Affiliation(s)
- Amanda G Thrift
- Department of Epidemiology and Preventive Medicine, Baker IDI Heart and Diabetes Institute, Monash University, Melbourne, Victoria, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Trachtman H, Hainer JW, Sugg J, Teng R, Sorof JM, Radcliffe J. Efficacy, safety, and pharmacokinetics of candesartan cilexetil in hypertensive children aged 6 to 17 years. J Clin Hypertens (Greenwich) 2009; 10:743-50. [PMID: 19090875 DOI: 10.1111/j.1751-7176.2008.00022.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This 4-week randomized, double blind, placebo-controlled study (N=240), 1-year open label trial (N=233), and single-dose pharmacokinetic study (N=22) evaluated candesartan cilexetil (3 doses) in hypertensive children aged 6 to 17 years. Seventy-one percent were 12 years of age or older, 71% were male, and 47% were black. Systolic (SBP)/diastolic (DBP) blood pressure declined 8.6/4.8-11.2/8.0 mm Hg with candesartan and 3.7/1.8 mm Hg with placebo (P<.01 compared to placebo for SBP and for the mid and high doses for DBP; placebo-corrected 4.9/3.0-7.5/6.2 mm Hg). The slopes for dose were not, however, different from zero (P>.05). The response rate (SBP and DBP <95th percentile) after 1 year was 53%. The pharmacokinetic profiles in 6- to 12- and 12- to 17-year-olds were similar and were comparable to adults. Eight candesartan patients discontinued treatment because of an adverse event. Candesartan is an effective, well-tolerated antihypertensive agent for children aged 6 to 17 years and has a pharmacokinetic profile that is similar to that in adults.
Collapse
Affiliation(s)
- Howard Trachtman
- Division of Pediatric Nephrology, Schneider Children's Hospital, New Hyde Park, NY, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Deficiency of intrarenal angiotensin II type 2 receptor impairs paired homeo box-2 and N-myc expression during nephrogenesis. Pediatr Nephrol 2008; 23:1769-77. [PMID: 18607644 DOI: 10.1007/s00467-008-0854-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 03/27/2008] [Accepted: 03/31/2008] [Indexed: 10/21/2022]
Abstract
We previously demonstrated that angiotensin II (Ang II) stimulates paired homeo box-2 (Pax-2) via the Ang II type 2 receptor (AT(2)R). The Pax-2 gene and N-myc play pivotal roles in renal morphogenesis via their effects on cell proliferation and differentiation in embryonic mesenchymal cells and embryonic mouse kidneys. Since AT(2)R knock-out (KO) mice have a phenotype that is similar to that of humans with congenital renal and urinary tract anomalies (CAKUT) and develop hypertension in adulthood, these mice and wild-type controls were used for this study. Embryonic kidneys isolated from E12 to term gestation were cultured in Dulbecco's modified Eagle's medium (DMEM) with or without Ang II (10(-6) M) for 24 h ex vivo. Renal morphogenesis was histologically assessed. Mean glomerular tuft volume was determined by the method of Weibel and Gomez with the aid of image analysis software. Pax-2 and N-myc gene expression were determined by immunostaining as well as by Western blotting and real-time-quantitative polymerase chain reaction (RT-qPCR). Glomerular size was significantly smaller, and Pax-2 and N-myc expression down-regulated, in kidneys of AT(2)R KO mice compared with those of wild-type mice. In ex vivo studies, Ang II stimulated Pax-2 and N-myc mRNA expression in embryonic kidneys of wild-type mice, but this stimulatory effect was absent in embryonic kidneys of AT(2)R KO mice. Taken together, these data indicate that intrarenal AT(2)R plays an important role in nephrogenesis. Deficiency of AT(2)R may impair both Pax-2 and N-myc expression, eventually resulting in glomerular hyperfiltration that may, ultimately, lead to later development of hypertension.
Collapse
|
13
|
Abstract
The decision to treat elevated arterial pressure in pregnancy depends on the risk and benefits imposed on the mother and the fetus. Treatment for mild-to-moderate hypertension during pregnancy may not reduce maternal or fetal risk. Severe hypertension, on the other hand, should be treated to decrease maternal risk. Methyldopa and beta-adrenoceptor antagonists have been used most extensively. In acute severe hypertension, intravenous labetalol or oral nifedipine are reasonable choices.
Collapse
Affiliation(s)
- Firas A Ghanem
- Section of Cardiology, Department of Medicine, The Brody School of Medicine, East Carolina University, Greenville, North Carolina 27834, USA
| | | |
Collapse
|
14
|
Sánchez SI, Seltzer AM, Fuentes LB, Forneris ML, Ciuffo GM. Inhibition of Angiotensin II receptors during pregnancy induces malformations in developing rat kidney. Eur J Pharmacol 2008; 588:114-23. [PMID: 18495111 DOI: 10.1016/j.ejphar.2008.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 03/27/2008] [Accepted: 04/03/2008] [Indexed: 11/25/2022]
Abstract
Evidence suggests that Angiotensin II plays an important role in the complex process of renal organogenesis. Rat kidney organogenesis starts between E13-14 and lasts up to 2 weeks after birth. The present study demonstrates histologic modifications and changes in receptor localisation in animals born from mothers treated with Angiotensin II, Losartan or PD123319 (1.0 mg/kg/day) during late pregnancy. Angiotensin II-treated animals exhibited very well developed tubules in the renal medulla in coincidence with higher AT(1) binding. Control animals exhibited angiotensin AT(2) binding in the outer stripe of the outer medulla, while in the Angiotensin II-treated animals binding was observed to the inner stripe. In Angiotensin II-treated 1-week-old animals, the nephrogenic zone contained fewer immature structures, and more developed collecting tubules than control animals. Treatment with Losartan resulted in severe renal abnormalities. For newborn and 1-week-old animals, glomeruli exhibited altered shape and enlarged Bowman spaces, in concordance with a loss of [(125)I]Angiotensin II binding in the cortex. Blockade with PD123319 led to an enlarged nephrogenic zone with increased number of immature glomeruli, and less glomeruli in the juxtamedullary area. Autoradiography showed a considerable loss of AT(1) binding in the kidney cortex of PD123319-treated animals at both ages. The present results show for the first time histomorphological and receptor localisation alterations following treatment with low doses of Losartan and PD123319 during pregnancy. These observations confirm previous assumptions that in the developing kidney Angiotensin II exerts stimulatory effects through AT(1) receptors that might be counterbalanced by angiotensin AT(2) receptors.
Collapse
Affiliation(s)
- Susana I Sánchez
- Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-CONICET), Facultad de Química, Bioquímica y Farmacia. - Universidad Nacional de San Luis, Ejército de los Andes 950, 5700 San Luis, Argentina
| | | | | | | | | |
Collapse
|
15
|
Affiliation(s)
- Jeffrey S. Gilbert
- From the Department of Physiology and Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Miss
| |
Collapse
|
16
|
Kobori H, Nangaku M, Navar LG, Nishiyama A. The intrarenal renin-angiotensin system: from physiology to the pathobiology of hypertension and kidney disease. Pharmacol Rev 2007; 59:251-87. [PMID: 17878513 DOI: 10.1124/pr.59.3.3] [Citation(s) in RCA: 866] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In recent years, the focus of interest on the role of the renin-angiotensin system (RAS) in the pathophysiology of hypertension and organ injury has changed to a major emphasis on the role of the local RAS in specific tissues. In the kidney, all of the RAS components are present and intrarenal angiotensin II (Ang II) is formed by independent multiple mechanisms. Proximal tubular angiotensinogen, collecting duct renin, and tubular angiotensin II type 1 (AT1) receptors are positively augmented by intrarenal Ang II. In addition to the classic RAS pathways, prorenin receptors and chymase are also involved in local Ang II formation in the kidney. Moreover, circulating Ang II is actively internalized into proximal tubular cells by AT1 receptor-dependent mechanisms. Consequently, Ang II is compartmentalized in the renal interstitial fluid and the proximal tubular compartments with much higher concentrations than those existing in the circulation. Recent evidence has also revealed that inappropriate activation of the intrarenal RAS is an important contributor to the pathogenesis of hypertension and renal injury. Thus, it is necessary to understand the mechanisms responsible for independent regulation of the intrarenal RAS. In this review, we will briefly summarize our current understanding of independent regulation of the intrarenal RAS and discuss how inappropriate activation of this system contributes to the development and maintenance of hypertension and renal injury. We will also discuss the impact of antihypertensive agents in preventing the progressive increases in the intrarenal RAS during the development of hypertension and renal injury.
Collapse
Affiliation(s)
- Hiroyuki Kobori
- Department of Medicine, Director of the Molecular Core in Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, New Orleans, LA 70112-2699, USA.
| | | | | | | |
Collapse
|