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Yao Y, Zhang L, Cheng F, Jiang Q, Ye Y, Ren Y, He Y, Su D, Cheng L, Shi G, Dai L, Deng H. PPARγ-dependent hepatic macrophage switching acts as a central hub for hUCMSC-mediated alleviation of decompensated liver cirrhosis in rats. Stem Cell Res Ther 2023; 14:184. [PMID: 37501214 PMCID: PMC10375757 DOI: 10.1186/s13287-023-03416-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 07/17/2023] [Indexed: 07/29/2023] Open
Abstract
BACKGROUND Decompensated liver cirrhosis (DLC), a terminal-stage complication of liver disease, is a major cause of morbidity and mortality in patients with hepatopathies. Human umbilical cord mesenchymal stem cell (hUCMSC) therapy has emerged as a novel treatment alternative for the treatment of DLC. However, optimized therapy protocols and the associated mechanisms are not entirely understood. METHODS We constructed a DLC rat model consistent with the typical clinical characteristics combined use of PB and CCL4. Performing dynamic detection of liver morphology and function in rats for 11 weeks, various disease characteristics of DLC and the therapeutic effect of hUCMSCs on DLC in experimental rats were thoroughly investigated, according to ascites examination, histopathological, and related blood biochemical analyses. Flow cytometry analysis of rat liver, immunofluorescence, and RT-qPCR was performed to examine the changes in the liver immune microenvironment after hucMSCs treatment. We performed RNA-seq analysis of liver and primary macrophages and hUCMSCs co-culture system in vitro to explore possible signaling pathways. PPARγ antagonist, GW9662, and clodronate liposomes were used to inhibit PPAR activation and pre-exhaustion of macrophages in DLC rats' livers, respectively. RESULTS We found that changing the two key issues, the frequency and initial phase of hUCMSCs infusion, can affect the efficacy of hUCMSCs, and the optimal hUCMSCs treatment schedule is once every week for three weeks at the early stage of DLC progression, providing the best therapeutic effect in reducing mortality and ascites, and improving liver function in DLC rats. hUCMSCs treatment skewed the macrophage phenotype from M1-type to M2-type by activating the PPARγ signaling pathway in the liver, which was approved by primary macrophages and hUCMSCs co-culture system in vitro. Both inhibition of PPARγ activation with GW9662 and pre-exhaustion of macrophages in DLC rats' liver abolished the regulation of hUCMSCs on macrophage polarization, thus attenuating the beneficial effect of hUCMSCs treatment in DLC rats. CONCLUSIONS These data demonstrated that the optimal hUCMSCs treatment effectively inhibits the ascites formation, prolongs survival and significantly improves liver structure and function in DLC rats through the activation of the PPARγ signaling pathway within liver macrophages. Our study compared the efficacy of different hUCMSCs infusion regimens for DLC, providing new insights on cell-based therapies for regenerative medicine.
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Affiliation(s)
- Yunqi Yao
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Lin Zhang
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Fuyi Cheng
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Qingyuan Jiang
- Department of Obstetrics, Sichuan Provincial Hospital for Women and Children, Chengdu, People's Republic of China
| | - Yixin Ye
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Yushuang Ren
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Yuting He
- Laboratory of Pathology, Key Laboratory of Transplant Engineering and Immunology, NHC, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Dongsheng Su
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Lin Cheng
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Gang Shi
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Lei Dai
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China
| | - Hongxin Deng
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Ke-yuan Road 4, No.1, Gao-peng Street, Chengdu, 610041, People's Republic of China.
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Li N, Ying Y, Yang B. Aquaporins in Edema. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:281-287. [PMID: 36717501 DOI: 10.1007/978-981-19-7415-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
One of the most prevalent indications of water-electrolyte imbalance is edema. Aquaporins (AQPs) are a protein family that can function as water channels. Osmoregulation and body water homeostasis are dependent on the regulation of AQPs. Human kidneys contain nine AQPs, five of which have been demonstrated to have a role in body water balance: AQP1, AQP2, AQP3, AQP4, and AQP7. Water imbalance is connected with AQP dysfunction. Hyponatremia with elevated AQP levels can accompany edema, which can be caused by disorders with low effective circulating blood volume and systemic vasodilation, such as congestive heart failure (CHF), hepatic cirrhosis, or the syndrome of incorrect antidiuretic hormone secretion (SIADH). In CHF, upregulation of AQP2 expression and targeting is critical for water retention. AQP2 is also involved in aberrant water retention and the formation of ascites in cirrhosis of the liver. Furthermore, water retention and hyponatremia in SIADH are caused by increased expression of AQP2 in the collecting duct. Fluid restriction, demeclocycline, and vasopressin type-2 receptor antagonists are widely utilized to treat edema. The relationship between AQPs and edema is discussed in this chapter.
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Affiliation(s)
- Nannan Li
- School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yi Ying
- School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Renoprotective Effect of the Histone Deacetylase Inhibitor CG200745 in DOCA-Salt Hypertensive Rats. Int J Mol Sci 2019; 20:ijms20030508. [PMID: 30691015 PMCID: PMC6387176 DOI: 10.3390/ijms20030508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/16/2019] [Accepted: 01/22/2019] [Indexed: 12/14/2022] Open
Abstract
The novel histone deacetylase inhibitor CG200745 was initially developed to treat various hematological and solid cancers. We investigated the molecular mechanisms associated with the renoprotective effects of CG200745 using deoxycorticosterone acetate (DOCA)-salt hypertensive (DSH) rats. DOCA strips (200 mg/kg) were implanted into rats one week after unilateral nephrectomy. Two weeks after DOCA implantation, DSH rats were randomly divided into two groups that received either physiological saline or CG200745 (5 mg/kg/day) for another two weeks. The extent of glomerulosclerosis and tubulointerstitial fibrosis was determined by Masson's trichrome staining. The renal expression of fibrosis and inflammatory markers was detected by semiquantitative immunoblotting, a polymerase chain reaction, and immunohistochemistry. Pathological signs such as glomerulosclerosis, tubulointerstitial fibrosis, increased systolic blood pressure, decreased creatinine clearance, and increased albumin-to-creatinine ratios in DSH rats were alleviated by CG200745 treatment compared to those manifestations in positive control animals. Furthermore, this treatment counteracted the increased expression of αSMA, TGF-β1, and Bax, and the decreased expression of Bcl-2 in the kidneys of DSH rats. It also attenuated the increase in the number of apoptotic cells in DSH rats. Thus, CG200745 can effectively prevent the progression of renal injury in DSH rats by exerting anti-inflammatory, anti-fibrotic, and anti-apoptotic effects.
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Snowdon VK, Lachlan NJ, Hoy AM, Hadoke PWF, Semple SI, Patel D, Mungall W, Kendall TJ, Thomson A, Lennen RJ, Jansen MA, Moran CM, Pellicoro A, Ramachandran P, Shaw I, Aucott RL, Severin T, Saini R, Pak J, Yates D, Dongre N, Duffield JS, Webb DJ, Iredale JP, Hayes PC, Fallowfield JA. Serelaxin as a potential treatment for renal dysfunction in cirrhosis: Preclinical evaluation and results of a randomized phase 2 trial. PLoS Med 2017; 14:e1002248. [PMID: 28245243 PMCID: PMC5330452 DOI: 10.1371/journal.pmed.1002248] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 02/02/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Chronic liver scarring from any cause leads to cirrhosis, portal hypertension, and a progressive decline in renal blood flow and renal function. Extreme renal vasoconstriction characterizes hepatorenal syndrome, a functional and potentially reversible form of acute kidney injury in patients with advanced cirrhosis, but current therapy with systemic vasoconstrictors is ineffective in a substantial proportion of patients and is limited by ischemic adverse events. Serelaxin (recombinant human relaxin-2) is a peptide molecule with anti-fibrotic and vasoprotective properties that binds to relaxin family peptide receptor-1 (RXFP1) and has been shown to increase renal perfusion in healthy human volunteers. We hypothesized that serelaxin could ameliorate renal vasoconstriction and renal dysfunction in patients with cirrhosis and portal hypertension. METHODS AND FINDINGS To establish preclinical proof of concept, we developed two independent rat models of cirrhosis that were characterized by progressive reduction in renal blood flow and glomerular filtration rate and showed evidence of renal endothelial dysfunction. We then set out to further explore and validate our hypothesis in a phase 2 randomized open-label parallel-group study in male and female patients with alcohol-related cirrhosis and portal hypertension. Forty patients were randomized 1:1 to treatment with serelaxin intravenous (i.v.) infusion (for 60 min at 80 μg/kg/d and then 60 min at 30 μg/kg/d) or terlipressin (single 2-mg i.v. bolus), and the regional hemodynamic effects were quantified by phase contrast magnetic resonance angiography at baseline and after 120 min. The primary endpoint was the change from baseline in total renal artery blood flow. Therapeutic targeting of renal vasoconstriction with serelaxin in the rat models increased kidney perfusion, oxygenation, and function through reduction in renal vascular resistance, reversal of endothelial dysfunction, and increased activation of the AKT/eNOS/NO signaling pathway in the kidney. In the randomized clinical study, infusion of serelaxin for 120 min increased total renal arterial blood flow by 65% (95% CI 40%, 95%; p < 0.001) from baseline. Administration of serelaxin was safe and well tolerated, with no detrimental effect on systemic blood pressure or hepatic perfusion. The clinical study's main limitations were the relatively small sample size and stable, well-compensated population. CONCLUSIONS Our mechanistic findings in rat models and exploratory study in human cirrhosis suggest the therapeutic potential of selective renal vasodilation using serelaxin as a new treatment for renal dysfunction in cirrhosis, although further validation in patients with more advanced cirrhosis and renal dysfunction is required. TRIAL REGISTRATION ClinicalTrials.gov NCT01640964.
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Affiliation(s)
- Victoria K Snowdon
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Neil J Lachlan
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna M Hoy
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Patrick W F Hadoke
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott I Semple
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
- Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Dilip Patel
- Department of Radiology, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Will Mungall
- Biological Services, University of Edinburgh, Edinburgh, United Kingdom
| | - Timothy J Kendall
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Adrian Thomson
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Ross J Lennen
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Maurits A Jansen
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Carmel M Moran
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Antonella Pellicoro
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Prakash Ramachandran
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Isaac Shaw
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Rebecca L Aucott
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Rajnish Saini
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States of America
| | - Judy Pak
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States of America
| | - Denise Yates
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | | | - Jeremy S Duffield
- Division of Nephrology and Lung Biology, University of Washington, Seattle, Washington, United States of America
| | - David J Webb
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - John P Iredale
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter C Hayes
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Jonathan A Fallowfield
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
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Scherzer P, Gal-Moscovici A, Sheikh-Hamad D, Popovtzer MM. Sodium-pump gene-expression, protein abundance and enzyme activity in isolated nephron segments of the aging rat kidney. Physiol Rep 2015; 3:3/6/e12369. [PMID: 26056060 PMCID: PMC4510615 DOI: 10.14814/phy2.12369] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Aging is associated with alteration in renal tubular functions, including sodium handling and concentrating ability. Na-K-ATPase plays a key role in driving tubular transport, and we hypothesized that decreased concentrating ability of the aging kidney is due in part to downregulation of Na-K-ATPase. In this study, we evaluated Na and K balance, aldosterone levels, and Na-K-ATPase gene expression, protein abundance, and activity in aging rat kidney. Na-K-ATPase activity (assayed microfluorometrically), mRNA (RT-PCR), and protein abundance (immunoblotting) were quantitated in the following isolated nephron segments: PCT, PST, MTAL, DCT, and CCD from 2, 8, 15, and 24 month-old-rats. In the course of aging, creatinine clearance decreased from 0.48 ± 0.02 mL/min/100 g BW to 0.28 ± 0.06 (P < 0.001) and aldosterone decreased from 23.6 ± 0.8 ng/dL to 13.2 ± 0.6 (P < 0.001). Serum Na+ and K+ increased by 4.0% and 22.5%, respectively. Na-K-ATPase activity, mRNA, and protein abundance of the α1 subunit displayed similar trends in all assayed segments; increasing in PCT and PST; decreasing in MTAL and DCT; increasing in CCD: in PCT they increased by 40%, 75%, and 250%, respectively; while in PST they increased by 80%, 50%, and 100%, respectively (P < 0.001). In MTAL they declined by 36%, 24%, and 34%, respectively, and in DCT by 38%, 59%, and 60%, respectively (P < 0.001). They were higher in CCD by 110%, 115%, and 246%, respectively (P < 0.001). Rats maintained Na/K balance; however with a steady state elevated serum K+. These results reveal quantitative changes in axial distribution of Na-K-ATPase at the level of gene expression, protein abundance, and activity in the nephrons of aging animals and may explain, in part, the pathophysiology of the senescent kidney.
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Affiliation(s)
- Pnina Scherzer
- Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem, Israel
| | - Anca Gal-Moscovici
- Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem, Israel
| | - David Sheikh-Hamad
- Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem, Israel Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Mordecai M Popovtzer
- Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem, Israel South Arizona VA Health Care System and University of Arizona, Tucson, Arizona
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Theilig F, Wu Q. ANP-induced signaling cascade and its implications in renal pathophysiology. Am J Physiol Renal Physiol 2015; 308:F1047-55. [PMID: 25651559 DOI: 10.1152/ajprenal.00164.2014] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 01/22/2015] [Indexed: 01/06/2023] Open
Abstract
The balance between vasoconstrictor/sodium-retaining and vasodilator/natriuretic systems is essential for maintaining body fluid and electrolyte homeostasis. Natriuretic peptides, such as atrial natriuretic peptide (ANP), belong to the vasodilator/natriuretic system. ANP is produced by the conversion of pro-ANP into ANP, which is achieved by a proteolytical cleavage executed by corin. In the kidney, ANP binds to the natriuretic peptide receptor-A (NPR-A) and enhances its guanylyl cyclase activity, thereby increasing intracellular cyclic guanosine monophosphate production to promote natriuretic and renoprotective responses. In the glomerulus, ANP increases glomerular permeability and filtration rate and antagonizes the deleterious effects of the renin-angiotensin-aldosterone system activation. Along the nephron, natriuretic and diuretic actions of ANP are mediated by inhibiting the basolaterally expressed Na(+)-K(+)-ATPase, reducing apical sodium, potassium, and protein organic cation transporter in the proximal tubule, and decreasing Na(+)-K(+)-2Cl(-) cotransporter activity and renal concentration efficiency in the thick ascending limb. In the medullary collecting duct, ANP reduces sodium reabsorption by inhibiting the cyclic nucleotide-gated cation channels, the epithelial sodium channel, and the heteromeric channel transient receptor potential-vanilloid 4 and -polycystin 2 and diminishes vasopressin-induced water reabsorption. Long-term ANP treatment may lead to NPR-A desensitization and ANP resistance, resulting in augmented sodium and water reabsorption. In mice, corin deficiency impairs sodium excretion and causes salt-sensitive hypertension. Characteristics of ANP resistance and corin deficiency are also encountered in patients with edema-associated diseases, highlighting the importance of ANP signaling in salt-water balance and renal pathophysiology.
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Affiliation(s)
- Franziska Theilig
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland; and
| | - Qingyu Wu
- Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Ohio
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Abstract
Nephrotic syndrome and liver cirrhosis are common clinical manifestations, and are associated with avid sodium retention leading to the development of edema and ascites. However, the mechanism for the sodium retention is still incompletely understood and the molecular basis remains undefined. We examined the changes of sodium (co)transporters and epithelial sodium channels (ENaCs) in the kidneys of experimental nephrotic syndrome and liver cirrhosis. The results demonstrated that puromycin- or HgCl2-induced nephrotic syndrome was associated with 1) sodium retention, decreased urinary sodium excretion, development of ascites, and increased plasma aldosterone level; 2) increased apical targeting of ENaC subunits in connecting tubule and collecting duct segments; and 3) decreased protein abundance of type 2 11β-hydroxysteroid dehydrogenase (11βHSD2). Experimental liver cirrhosis was induced in rats by CCl4 treatment or common bile duct ligation. An increased apical targeting of alpha-, beta-, and gamma-ENaC subunits in connecting tubule, and cortical and medullary collecting duct segments in sodium retaining phase of liver cirhosis but not in escape phase of sodium retention. Immunolabeling intensity of 11βHSD2 in the connecting tubule and cortical collecting duct was significantly reduced in sodium retaining phase of liver cirrhosis, and this was confirmed by immunoblotting. These observations therefore strongly support the view that the renal sodium retention associated with nephrotic syndrome and liver cirrhosis is caused by increased sodium reabsorption in the aldosterone sensitive distal nephron including the connecting tubule and collecting duct, and increased apical targeting of ENaC subunits plays a role in the development of sodium retention in nephrotic syndrome and liver cirrhosis.
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Affiliation(s)
- Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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Bae EH, Kim IJ, Joo SY, Kim EY, Kim CS, Choi JS, Ma SK, Kim SH, Lee JU, Kim SW. Renoprotective Effects of Sildenafil in DOCA-Salt Hypertensive Rats. ACTA ACUST UNITED AC 2012; 36:248-57. [DOI: 10.1159/000343414] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2012] [Indexed: 11/19/2022]
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Bae EH, Ma SK, Lee J, Kim SW. Altered regulation of renal nitric oxide and atrial natriuretic peptide systems in angiotensin II-induced hypertension. ACTA ACUST UNITED AC 2011; 170:31-7. [PMID: 21616096 DOI: 10.1016/j.regpep.2011.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 04/22/2011] [Accepted: 05/10/2011] [Indexed: 11/25/2022]
Abstract
The present study was aimed to determine whether there is an altered role of local nitric oxide (NO) and atrial natriuretic peptide (ANP) systems in the kidney in association with the angiotensin (Ang) II-induced hypertension. Male Sprague-Dawley rats were used. Ang II (100 ng·min⁻¹·kg⁻¹) was infused through entire time course. Thirteenth day after beginning the regimen, kidneys were taken. The protein expression of NO synthase (NOS) and nitrotyrosine was determined by semiquantitative immunoblotting. The mRNA expression of components of ANP system was determined by real-time polymerase chain reaction. The activities of soluble and particulate guanylyl cyclases were determined by the amount of cGMP generated in responses to sodium nitroprusside and ANP, respectively. There developed hypertension and decreased creatinine clearance in the experimental group. The protein expression of eNOS, nNOS and nitrotyrosine was increased in the cortex, while that of iNOS remained unaltered. The urinary excretion of NO increased in Ang II-induced hypertensive rats. The catalytic activity of soluble guanylyl cyclase was blunted in the glomerulus in Ang II-induced hypertensive rats. The mRNA expression of ANP was increased in Ang II-induced hypertensive rats. Neither the expression of NPR-A nor that of NPR-C was changed. The protein expression of neutral endopeptidase was decreased and the activity of particulate guanylyl cyclase was blunted in the glomerulus and papilla in Ang II-induced hypertensive rats. In conclusion, the synthesis of NO and ANP was increased in the kidney of Ang II-induced hypertension, while stimulated cGMP response was blunted. These results suggest desensitization of guanylyl cyclase in the kidney of Ang II-induced hypertensive rats, which may contribute to the associated renal vasoconstriction and hypertension.
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Affiliation(s)
- Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
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Bae EH, Kim SW. Changes in endothelin receptor type B and neuronal nitric oxide synthase in puromycin aminonucleoside-induced nephrotic syndrome. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2010; 14:223-8. [PMID: 20827336 DOI: 10.4196/kjpp.2010.14.4.223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 07/29/2010] [Accepted: 08/06/2010] [Indexed: 11/15/2022]
Abstract
The collecting duct endothelin (ET) system, which involves ET-1 and its two receptors, may play a role in the regulation of renal sodium in association with the nitric oxide synthase (NOS) system. We determined whether sodium retention is associated with changes in the endothelin and NOS systems at different stages (i.e., a sodium retaining stage and a compensatory stage) of nephrotic syndromes. On day 7 after puromycin aminonucleoside (PAN) injection, urinary sodium excretion was decreased, ascites had developed, and there was a positive sodium balance. ET-1 mRNA expression was increased in the inner medulla of the kidney, whereas protein expression of ET receptor type B (ET(B)R) was unchanged. The expression of neuronal NOS (nNOS) was decreased in the inner medulla. On day 14, urinary sodium excretion was unchanged compared with controls. The expression of ET(B)R increased, while nNOS expression in the inner medulla was comparable to controls. These findings suggest that decreased nNOS plays a role in the development of sodium retention in the nephrotic syndrome. Recovery of nNOS and increased renal ET(B)R synthesis may promote sodium excretion in later stages of the nephrotic syndrome (on day 14).
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Affiliation(s)
- Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju 501-757, Korea
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Zhao S, Fu YM, Li XF, Jin ZF, Zhao RB, Huang Q, Zhang FM, Zhang WH. Alterations of bone marrow sinusoidal endothelium in rat and patients with liver cirrhosis. Dig Dis Sci 2010; 55:654-61. [PMID: 19333758 DOI: 10.1007/s10620-009-0785-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 03/09/2009] [Indexed: 12/29/2022]
Abstract
Whether bone marrow changes occur and potentially contribute to the hematological abnormalities in liver cirrhosis remain unclear. In this study, we established a rat model of liver cirrhosis induced by carbon tetrachloride. Electron microscopy examination showed focal lesions in bone marrow sinusoidal endothelium and hematopoietic cells in animals with cirrhosis. With the persistence of liver cirrhosis, injuries of bone marrow sinusoidal endothelium progressed from mild mitochondrial changes to nuclear pycnosis and cell disruption, and the trilineage hematopoietic cells showed apoptosis and necrosis. Immunohistochemistry revealed increased expression of E-selectin, P-selectin and vWF in bone marrow sinusoidal endothelium of the cirrhotic rats, which was consistent with the data from semiquantitative reverse transcriptase-polymerase chain reaction analysis. Autopsy specimens from patients with liver cirrhosis (in the absence of other disease) showed the same findings as detected by immunohistochemistry in animal models. The results provide evidence of the association between liver cirrhosis and bone marrow alterations by demonstrating the bone marrow sinusoidal endothelium lesions in both a rat model and patients. It also indicates that activation or injury of bone marrow sinusoidal endothelium mediated by E-selectin, P-selectin, and vWF might have a role in pathogenesis of bone marrow changes during liver cirrhosis. The lesions of bone marrow sinusoidal endothelium might contribute to the hematological abnormalities in the end stage of liver disease.
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Affiliation(s)
- Song Zhao
- Department of General Surgery, First Affiliated Hospital, Harbin Medical University, Harbin, China
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Bae EH, Kim IJ, Park JW, Ma SK, Lee JU, Kim SW. Renoprotective effect of rosuvastatin in DOCA-salt hypertensive rats. Nephrol Dial Transplant 2009; 25:1051-9. [DOI: 10.1093/ndt/gfp604] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lütken SC, Kim SW, Jonassen T, Marples D, Knepper MA, Kwon TH, Frøkiaer J, Nielsen S. Changes of renal AQP2, ENaC, and NHE3 in experimentally induced heart failure: response to angiotensin II AT1 receptor blockade. Am J Physiol Renal Physiol 2009; 297:F1678-88. [PMID: 19776175 DOI: 10.1152/ajprenal.00010.2009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Heart failure (HF) was induced by ligation of the left anterior descending artery (LAD). Left ventricular end-diastolic pressure (LVEDP) >25 mmHg (at day 23 after LAD ligation) was the inclusion criterion. The rats were divided into three groups: sham-operated (Sham, n = 23, LVEDP: 5.6 +/- 0.6 mmHg), HF (n = 14, LVEDP: 29.4 +/- 1.4 mmHg), and candesartan (1 mg.kg(-1).day(-1) sc)-treated HF (HF + Can, n = 9, LVEDP: 29.2 +/- 1.2 mmHg). After 7 days (i.e., 29 days after LAD ligation) semiquantitative immunoblotting revealed increased abundance of inner medulla aquaporin-2 (AQP2) and AQP2 phosphorylated at Ser(256) (p-AQP2) in HF. There was also markedly enhanced apical targeting of AQP2 and p-AQP2 in inner medullary collecting duct (IMCD) in HF compared with Sham rats, shown by immunocytochemistry. Candesartan treatment significantly reversed the increases in both AQP2 and p-AQP2 expression and targeting. In contrast, there were only modest changes in other collecting duct segments. Semiquantitative immunoblots revealed increased expression of type 3 Na(+)/H(+) exchanger (NHE3) and Na(+)-K(+)-2Cl(-) cotransporter (NKCC2) in kidneys from HF compared with Sham rats: both effects were reversed or prevented by candesartan treatment. The protein abundance of alpha-epithelial sodium channel (alpha-ENaC) was increased while beta-ENaC and gamma-ENaC expression was decreased in the cortex and outer stripe of the outer medulla in HF compared with Sham rats, which was partially reversed by candesartan treatment. These findings strongly support an important role of angiotensin II in the pathophysiology of renal water and sodium retention associated with HF.
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Affiliation(s)
- Sophie C Lütken
- Water and Salt Research Center, Institute of Clinical Medicine, Univ. of Aarhus, DK-8200 Aarhus N, Denmark
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14
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Bae EH, Lee J, Ma SK, Kim IJ, Frøkiaer J, Nielsen S, Kim SY, Kim SW. alpha-Lipoic acid prevents cisplatin-induced acute kidney injury in rats. Nephrol Dial Transplant 2009; 24:2692-700. [PMID: 19376830 DOI: 10.1093/ndt/gfp176] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Cisplatin-induced nephropathy has been related to increased lipid peroxide formation and decreased activity of antioxidant enzymes in the kidney. The present study aimed to examine whether treatment with alpha-lipoic acid (alpha-LA) prevents the cisplatin-induced nephrotoxicity. METHODS Two groups of rats were treated with cisplatin, one of which being cotreated with alpha-LA. The control group was treated with vehicle only. Four days later, the expression of aquaporins and sodium transporters was determined in the kidney by immunoblotting and immunohistochemistry. The arginine vasopressin-stimulated generation of cAMP was measured by radioimmunoassay. The expression of nitric oxide synthases (NOS) was determined by immunoblotting. The mRNA expression of endothelin-1 (ET-1) and tumour necrosis factor (TNF)-alpha was measured by real-time PCR. Apoptosis was examined by TUNEL staining. RESULTS Following the treatment with cisplatin, urinary volume and fractional excretion of sodium increased. Accordingly, the expression of aquaporins 1-3, Na,K-ATPase, NHE3 and NKCC2 was decreased. The expression of adenylyl cyclase VI and vasopressin-stimulated cAMP generation was decreased. The expression of inducible NOS was increased, while that of endothelial NOS decreased. The ET-1 expression was increased. TUNEL-positive cells were increased, in association with an increased expression of TNF-alpha. alpha-LA treatment prevented dysregulation of these parameters and resumed the renal function. CONCLUSION alpha-LA may prevent the cisplatin-induced nephrotoxicity, possibly through preserving the activities of NO and ET systems and inhibiting the development of apoptosis.
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Affiliation(s)
- Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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15
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Bae EH, Lee J, Ma SK, Kim SW. Changes of atrial natriuretic Peptide system in rats with puromycin aminonucleoside-induced nephrotic syndrome. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:1-7. [PMID: 19885019 DOI: 10.4196/kjpp.2009.13.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sodium retention is a hallmark of nephrotic syndrome. We investigated whether sodium retention is associated with changes of natriuretic peptide system at different stages (i.e., a sodium retaining stage and a compensatory stage) of nephrotic syndrome. At day 7 after PAN (puromycin aminonucleoside) injection, the urinary excretion of sodium was decreased, along with the development of ascites and positive sodium balance. The plasma and urinary ANP (atrial natriuretic peptide) immunoreactivities were increased. ANP mRNA expression was increased in the heart and kidney, whereas that of NPR (natriuretic peptide receptor)-A and NPR-C mRNA was decreased in the kidney. The expression of NEP was decreased in the kidney. At day 14, urinary excretion of sodium did not differ from the control. The plasma ANP level and heart ANP mRNA expression returned to their control values. The expression of ANP mRNA in the kidney was increased in association with increased urinary ANP immunoreactivities. The expression of NPR-A in the kidney became normal, whereas that of NPR-C kept decreased. The expression of NEP (neutral endopeptidase) remained decreased. These findings suggest that the increased renal ANP synthesis in association with decreased metabolism via NEP and NPR-C may play a compensatory role against the development of sodium retention in nephrotic syndrome. The decreased of NPR-A expression in the kidney may contribute to the ANP resistance at day 7. The subsequent recovery of NPR-A expression may play a role in promoting sodium excretion in later stage (at day 14).
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Affiliation(s)
- Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju 501-757, Korea
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16
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Olesen ETB, de Seigneux S, Wang G, Lütken SC, Frøkiaer J, Kwon TH, Nielsen S. Rapid and segmental specific dysregulation of AQP2, S256-pAQP2 and renal sodium transporters in rats with LPS-induced endotoxaemia. Nephrol Dial Transplant 2009; 24:2338-49. [PMID: 19193739 DOI: 10.1093/ndt/gfp011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Acute renal failure (ARF) is a frequent complication of sepsis. Characteristics of ARF in sepsis are impaired urinary concentration, increased natriuresis and decreased glomerular filtration rate (GFR), in which inducible nitric oxide synthase (iNOS) has been revealed to play a role. Aims. We aimed to investigate renal water and sodium excretion and in parallel the segmental regulation of renal AQP2 and major sodium transporters in rats with acute LPS-induced endotoxaemia. Next, we aimed to examine the changes of iNOS expression and activated macrophage infiltration in the kidney and the effects of iNOS inhibition on AQP2 and NKCC2 expression in LPS rats. METHODS Rats were treated with LPS (i.p.) or with LPS + iNOS inhibitor L-NIL, and 6 h later kidneys were subjected to semiquantitative immunoblotting and immunohistochemistry. RESULTS Polyuria and increased natriuresis were seen 6 h after LPS injection alongside downregulation of both AQP2 and S256-phosphorylated AQP2 in CTX/OSOM and ISOM but not in inner medulla (IM). Thick ascending limb sodium transporters NHE3 and NKCC2 were downregulated in ISOM and NaPi2 was decreased in CTX/OSOM, whereas NCC and ENaC were not consistently downregulated. Immunolabelling intensity of iNOS was increased in vascular structures and transitional epithelium, and an infiltration of activated macrophages was seen in CTX and ISOM. L-NIL co-treatment prevented the downregulation of NKCC2 but not AQP2 in LPS rats. CONCLUSIONS Early downregulation of AQP2 and sodium transporters takes place segmentally in the kidney after LPS administration. In addition, an infiltration of activated macrophages and increased iNOS expression may play a role in the urinary concentrating defect in acute LPS-induced entotoxaemia.
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Affiliation(s)
- Emma T B Olesen
- The Water and Salt Research Centre, Institute of Anatomy, University of Aarhus, Aarhus, Denmark
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Camostat mesilate inhibits prostasin activity and reduces blood pressure and renal injury in salt-sensitive hypertension. J Hypertens 2009; 27:181-9. [PMID: 19145783 DOI: 10.1097/hjh.0b013e328317a762] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Prostasin, a glycosylphosphatidylinositol-anchored serine protease, regulates epithelial sodium channel (ENaC) activity. Sodium reabsorption through ENaC in distal nephron segments is a rate-limiting step in transepithelial sodium transport. Recently, proteolytic cleavage of ENaC subunits by prostasin has been shown to activate ENaC. Therefore, we hypothesized that serine protease inhibitors could inhibit ENaC activity in the kidney, leading to a decrease in blood pressure. We investigated the effects of camostat mesilate, a synthetic serine protease inhibitor, and FOY-251, an active metabolite of camostat mesilate, on sodium transport in the mouse cortical collecting duct cell line (M-1 cells) and on blood pressure in Dahl salt-sensitive rats. Treatment with camostat mesilate or FOY-251 decreased equivalent current (Ieq) in M-1 cells in a dose-dependent manner and inhibited the protease activity of prostasin in vitro. Silencing of the prostasin gene also reduced equivalent current in M-1 cells. The expression level of prostasin protein was not changed by application of camostat mesilate or FOY-251 to M-1 cells. Oral administration of camostat mesilate to Dahl salt-sensitive rats fed a high-salt diet resulted in a significant decrease in blood pressure with elevation of the urinary Na/K ratio, decrease in serum creatinine, reduction in urinary protein excretion, and improvement of renal injury markers such as collagen 1, collagen 3, transforming growth factor-beta1, and nephrin. These findings suggest that camostat mesilate can decrease ENaC activity in M-1 cells probably through the inhibition of prostasin activity, and that camostat mesilate can have beneficial effects on both hypertension and kidney injury in Dahl salt-sensitive rats. Camostat mesilate might represent a new class of antihypertensive drugs with renoprotective effects in patients with salt-sensitive hypertension.
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Affiliation(s)
- Tae-Hwan Kwon
- Water and Salt Research Center, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark
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Bhalla V, Hallows KR. Mechanisms of ENaC regulation and clinical implications. J Am Soc Nephrol 2008; 19:1845-54. [PMID: 18753254 DOI: 10.1681/asn.2008020225] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The epithelial Na+ channel (ENaC) transports Na+ across tight epithelia, including the distal nephron. Different paradigms of ENaC regulation include extrinsic and intrinsic factors that affect the expression, single-channel properties, and intracellular trafficking of the channel. In particular, recent discoveries highlight new findings regarding proteolytic processing, ubiquitination, and recycling of the channel. Understanding the regulation of this channel is critical to the understanding of various clinical phenomena, including normal physiology and several diseases of kidney and lung epithelia, such as blood pressure (BP) control, edema, and airway fluid clearance. Significant progress has been achieved in this active field of research. Although ENaC is classically thought to be a mediator of BP and volume status through Na+ reabsorption in the distal nephron, several studies in animal models highlight important roles for ENaC in lung pathophysiology, including in cystic fibrosis. The purpose of this review is to highlight the various modes and mechanisms of ENaC regulation, with a focus on more recent studies and their clinical implications.
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Affiliation(s)
- Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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Bae EH, Lee KS, Lee J, Ma SK, Kim NH, Choi KC, Frøkiaer J, Nielsen S, Kim SY, Kim SZ, Kim SH, Kim SW. Effects of alpha-lipoic acid on ischemia-reperfusion-induced renal dysfunction in rats. Am J Physiol Renal Physiol 2007; 294:F272-80. [PMID: 18032550 DOI: 10.1152/ajprenal.00352.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether alpha-lipoic acid (alpha-LA), an antioxidant, attenuates the ischemia-reperfusion (I/R)-induced dysregulation of these transporters. Both renal pedicles of male Sprague-Dawley rats were clamped for 40 min. alpha-LA (80 mg/kg) was administered intraperitoneally before and immediately after induction of ischemia. After 2 days, the expression of aquaporins (AQPs), sodium transporters, and nitric oxide synthases (NOS) was determined in the kidney by immunoblotting and immunohistochemistry. The expression of endothelin-1 (ET-1) mRNA was determined by real-time PCR. Activities of adenylyl cyclase and guanylyl cyclase were measured by stimulated generation of cAMP and cGMP, respectively. The expression of AQP1-3 as well as that of the alpha(1)-subunit of Na-K-ATPase, type 3 Na/H exchanger, Na-K-2Cl cotransporter, and Na-Cl cotransporter was markedly decreased in response to I/R. The expression of type VI adenylyl cyclase was decreased in I/R-injured rats, which was counteracted by the treatment of alpha-LA. AVP-stimulated cAMP generation was blunted in I/R rats and was then ameliorated by alpha-LA treatment. alpha-LA treatment attenuated the downregulation of AQPs and sodium transporters. The expression of endothelial NOS was decreased in I/R rats, which was prevented by alpha-LA. The cGMP generation in response to sodium nitroprusside was blunted in I/R rats, which was also significantly prevented by alpha-LA. The mRNA expression of ET-1 was increased, which was recovered to the control level by alpha-LA treatment. In conclusion, alpha-LA treatment prevents I/R-induced dysregulation of AQPs and sodium transporters in the kidney, possibly through preserving normal activities of local AVP/cAMP, nitric oxide/cGMP, and ET systems.
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Affiliation(s)
- Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Medical School, Hakdong 8, Gwangju 501-757, Korea
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21
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Ackermann D, Mordasini D, Cheval L, Imbert-Teboul M, Vogt B, Doucet A. Sodium retention and ascites formation in a cholestatic mice model: role of aldosterone and mineralocorticoid receptor? Hepatology 2007; 46:173-9. [PMID: 17596887 DOI: 10.1002/hep.21699] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
UNLABELLED Renal sodium retention in experimental liver cirrhosis originates from the distal nephron sensitive to aldosterone. The aims of this study were to (1) determine the exact site of sodium retention along the aldosterone-sensitive distal nephron, and (2) to evaluate the role of aldosterone and mineralocorticoid receptor activation in this process. Liver cirrhosis was induced by bile duct ligation in either adrenal-intact or corticosteroid-clamped mice. Corticosteroid-clamp was achieved through adrenalectomy and corticosteroid supplementation with aldosterone and dexamethasone via osmotic minipumps. 24-hours renal sodium balance was evaluated in metabolic cages. Activity and expression of sodium- and potassium-dependent adenosine triphosphatase were determined in microdissected segments of nephron. Within 4-5 weeks, cirrhosis induced sodium retention in adrenal-intact mice and formation of ascites in 50% of mice. At that time, sodium- and potassium-dependent adenosine triphosphatase activity increased specifically in cortical collecting ducts. Hyperaldosteronemia was indicated by increases in urinary aldosterone excretion and in sgk1 (serum- and glucocorticoid-regulated kinase 1) mRNA expression in collecting ducts. Corticosteroid-clamp prevented induction of sgk1 but not cirrhosis-induced sodium retention, formation of ascites and stimulation of sodium- and potassium-dependent adenosine triphosphatase activity and expression (mRNA and protein) in collecting duct. These findings demonstrate that sodium retention in cirrhosis is independent of hyperaldosteronemia and of the activation of mineralocorticoid receptor. CONCLUSION Bile duct ligation in mice induces cirrhosis which, within 4-5 weeks, leads to the induction of sodium- and potassium-dependent adenosine triphosphatase in cortical collecting ducts, to renal sodium retention and to the formation of ascites. Sodium retention, ascites formation and induction of sodium- and potassium-dependent adenosine triphosphatase are independent of the activation of mineralocorticoid receptors by either aldosterone or glucocorticoids.
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Affiliation(s)
- Daniel Ackermann
- Laboratoire de Physiologie et Génomique Rénales, CNRS/UPMC UMR 7134, IFR 58, Institut des Cordeliers, Paris cedex, France
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22
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Thiesson HC, Jensen BL, Bistrup C, Ottosen PD, McNeilly AD, Andrew R, Seckl J, Skøtt O. Renal sodium retention in cirrhotic rats depends on glucocorticoid-mediated activation of mineralocorticoid receptor due to decreased renal 11β-HSD-2 activity. Am J Physiol Regul Integr Comp Physiol 2007; 292:R625-36. [PMID: 16917017 DOI: 10.1152/ajpregu.00418.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Downregulation of the renal glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD-2) during liver cirrhosis may allow activation of the mineralocorticoid receptor (MR) by glucocorticoids and contribute to sodium retention. We tested this hypothesis in male Wistar rats with decompensated liver cirrhosis and ascites 7 wk after bile duct ligation (BDL). Renal 11β-HSD-2 mRNA, protein, and activity were significantly decreased in decompensated rats. The urinary Na+/K+ ratio was reduced by 40%. Renal epithelial sodium channel (ENaC) mRNA and immunostaining were only slightly affected. Complete metabolic studies, including fecal excretion, showed that the BDL rats had avid renal sodium retention. Treatment of the BDL rats with dexamethasone suppressed endogenous glucocorticoid production, normalized total sodium balance and renal sodium excretion, and reduced ascites formation to the same degree as direct inhibition of MR with K-canrenoate. Total potassium balance was negative in the BDL rats, whereas renal potassium excretion was unchanged. In the distal colon, expression of ENaC was increased in BDL rats. Fecal potassium excretion was increased in cirrhotic rats, and this was corrected by treatment with K-canrenoate but not dexamethasone. We conclude that development of sodium retention and decompensation in cirrhotic rats is associated with downregulation of renal 11β-HSD-2 activity and inappropriate activation of renal sodium reabsorption by endogenous glucocorticoids. In addition, the overall potassium loss in the BDL model is due to increased fecal potassium excretion, which is associated with upregulation of ENaC in distal colon.
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Affiliation(s)
- Helle C Thiesson
- Department of Physiology and Pharmacology, University of Southern Denmark, Odense
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Abstract
The discovery of aquaporin-1 (AQP1) explained the long-standing biophysical question of how water specifically crosses biological membranes. These studies led to the identification of a whole new family of membrane proteins, the aquaporin water channels. At present, at least eight aquaporins are expressed at distinct sites in the kidney and four members of this family (AQP1-4) have been demonstrated to play pivotal roles in the physiology and pathophysiology for renal regulation of body water balance. In the present review, a number of inherited and acquired conditions characterized by urinary concentration defects as well as common diseases associated with severe water retention are discussed with relation to the role of aquaporins in regulation and dysregulation of renal water transport.
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Affiliation(s)
- S Nielsen
- The Water and Salt Research Center, University of Aarhus, Aarhus C, Denmark.
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Riazi S, Madala-Halagappa VK, Hu X, Ecelbarger CA. Sex and body-type interactions in the regulation of renal sodium transporter levels, urinary excretion, and activity in lean and obese zucker rats. ACTA ACUST UNITED AC 2006; 3:309-27. [PMID: 17582372 DOI: 10.1016/s1550-8579(06)80219-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Female humans and rodents are relatively protected against the development of hypertension and renal disease. Whether this protection is modified during insulin resistance and obesity, however, is not known. OBJECTIVE Because renal sodium reabsorption has a central role in determining blood pressure, we hypothesized that lean female rats would bave reduced renal expression, activity, and urinary excretion of 8 major sodium transporters/channels. METHODS Lean and obese, male and female Zucker rats (n = 4-8 per group) were fed progressively higher levels of dietary NaCl over a period of 54 days. Urinary excretion of renal sodium transport proteins was determined for 3 different dietary levels (0.04%, 0.4%, and 4%) of NaCl. With the high-NaCl diet, natriuretic responses to benzamil, furosemide, and thiazide were used as in vivo markers for activity of the epithelial sodium channel (ENaC), the bumetanide-sensitive Na-K-2C1 cotransporter (NKCC2), and the thiazide-sensitive NaCl cotransporter (NCC), respectively. RESULTS Female rats (of both body types) had lower plasma renin activity and insulin levels than their male counterparts. Likewise, immunoblotting revealed female rats had increased whole kidney abundance of NCC and of the alpha, beta, and gamma subunits of ENaC, as well as decreased abundance of the type 3 sodium hydrogen exchanger (NHE3), type 2 sodium phosphate cotransporter (NaPi-2), and alpha-1 sodium-potassium-adenosine triphosphatase (Na-K-ATPase), compared with males. Obese rats had reduced levels of NKCC2, NHE3, and gamma-ENaC, but higher levels of NaPi-2 and NCC. Urine excretion of sodium transporters in lean female rats was nearly undetectable, whereas obese rats of both sexes excreted markedly more NKCC2 and NCC, which agreed with greater natriuretic responses to thiazide and furosemide. CONCLUSIONS Obese female rats are similar to lean female rats with regard to the sex-distinct pattern of renal sodium transporters. However, obese female rats are more like obese male rats with regard to increased natriuretic response tofurosemide and thiazide, and to urine excretion of several transporters including NCC. Our results suggest that, with obesity, there is some loss of the protective female advantage.
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Affiliation(s)
- Shahla Riazi
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC 20057, USA
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Frey FJ. Impaired 11 beta-hydroxysteroid dehydrogenase contributes to renal sodium avidity in cirrhosis: hypothesis or fact? Hepatology 2006; 44:795-801. [PMID: 17006915 DOI: 10.1002/hep.21381] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Exaggerated renal sodium retention with concomitant potassium loss is a hallmark of cirrhosis and contributes to the accumulation of fluid as ascites, pleural effusion, or edema. This apparent mineralocorticoid effect is only partially explained by increased aldosterone concentrations. I present evidence supporting the hypothesis that cortisol confers mineralocorticoid action in cirrhosis. The underlying molecular pathology for this mineralocorticoid receptor (MR) activation by cortisol is a reduced activity of the 11 beta-hydroxysteroid dehydrogenase type 2, an enzyme protecting the MR from promiscuous activation by cortisol in healthy mammalians.
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Affiliation(s)
- Felix J Frey
- Department of Nephrology and Hypertension, Inselspital, University of Berne, Switzerland.
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Li D, Zhang LL, Hou HS, Shi Q, Shen BJ. Dynamic changes of liver in cirrhosis model of rabbits. Shijie Huaren Xiaohua Zazhi 2006; 14:1403-1407. [DOI: 10.11569/wcjd.v14.i14.1403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To establish a relatively simple and feasible rabbit model of liver cirrhosis and analyze the dynamic changes of function and histopathology of cirrhotic liver.
METHODS: Twenty-four New Zealand rabbits were divided into two groups, of which twenty were received subcutaneous injection of carbon tetrachloride (CCl4) along with gastric infusion of edible ethanol for eight weeks. Animals in control group were fed with regular water and injected subcutaneously with the same quantity of olive oil. The development of hepatic fibrosis was recorded by Masson's trichrome method fortnightly. Blood samples were collected to measure the blood protein and enzymes fortnightly.
RESULTS: After treatment with CCl4, hepatic fibrosis was aggravated with time went by. As compared with those in normal controls, the levels of aspartate transaminase (AST) and alanine aminotransferase (ALT) in the experimental groups were increased significantly (AST: 983.5 ± 116.7 nkat/L vs 650.1 ± 133.4 nkat/L, P = 0.03; ALT: 1867.1 ± 200.1 nkat/L vs 883.5 ± 116.7 nkat/L, P = 0.01), while the level of gamma-glutamyl transpeptidase (GGT) was decreased (100.1 ± 33.3 nkat/L vs 366.7 ± 50.1 nkat/L, P = 0.01) at the end of 8 wk. Typical features of liver cirrhosis and the formation of false lobe were observed at the end of 8 wk.
CONCLUSION: Rabbit models of liver cirrhosis, with a low mortality and high success rate, can be established by combination of CCl4 and ethanol in a relatively short time.
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Ecelbarger CA. Role of the aldosterone-sensitive distal nephron in the sodium retention associated with liver cirrhosis. Kidney Int 2006; 69:10-2. [PMID: 16374415 DOI: 10.1038/sj.ki.5000095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The renal mechanisms underlying sodium retention during liver cirrhosis have been difficult to elucidate. Kim and associates describe a biphasic pattern of regulation of the renal epithelial sodium channel in the common bile duct ligation model, shedding some light on this issue.
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Affiliation(s)
- C A Ecelbarger
- Department of Medicine, Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20057-1412, USA.
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de Seigneux S, Kim SW, Hemmingsen SC, Frøkiaer J, Nielsen S. Increased expression but not targeting of ENaC in adrenalectomized rats with PAN-induced nephrotic syndrome. Am J Physiol Renal Physiol 2006; 291:F208-17. [PMID: 16403831 DOI: 10.1152/ajprenal.00399.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Sodium retention is a hallmark of nephrotic syndrome (NS). Puromycin aminonucleoside (PAN)-induced NS is associated with high aldosterone levels and increased ENaC expression and apical targeting. However, the mechanisms associated with increased apical targeting of ENaC in NS remain undefined, and it is unclear whether this is secondary to high aldosterone levels and whether aldosterone and/or apical ENaC targeting are important for the development of sodium retention. This study aimed at uncovering 1) whether aldosterone is essential for sodium retention in PAN-induced NS, 2) whether ENaC expression or apical targeting is secondary to high aldosterone levels, and 3) the role of aldosterone in the dysregulation of sodium transporters in NS. Puromycin treatment of adrenalectomized (ADX) rats supplemented with dexamethasone induced sodium retention despite the absence of aldosterone. Immunocytochemical analyses revealed an absence of enhanced apical targeting of ENaC subunits in PAN-treated ADX (ADX-PAN) rats, with distribution of labeling similar to adrenalectomized dexamethasone-treated control rats (ADX). Moreover, ENaC subunit abundance was increased in ADX-PAN rats. The abundance of aquaporin-2 was unchanged, whereas apical targeting was enhanced. Key sodium transporters were downregulated as previously observed in nonadrenalectomized puromycin-treated rats (Kim SW, Wang W, Nielsen J, Praetorius J, Kwon TH, Knepper MA, Frøkiaer J, and Nielsen S. Am J Physiol Renal Physiol 286: F922-F935, 2004), whereas the global expression of the alpha1-subunit of the Na-K-ATPase was unchanged. In conclusion, PAN treatment in the absence of aldosterone induced sodium retention, increased ENaC expression, but did not change the subcellular distribution of ENaC. This indicates that the previously observed enhanced apical targeting of ENaC in PAN-induced NS (Kim SW, Wang W, Nielsen J, Praetorius J, Kwon TH, Knepper MA, Frøkiaer J, and Nielsen S. Am J Physiol Renal Physiol 286: F922-F935, 2004) is caused by aldosterone and that development of sodium retention can occur in the absence of aldosterone in NS.
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Affiliation(s)
- Sophie de Seigneux
- The Water and Salt Research Center, Bldg. 233/234, University of Aarhus, and Institute of Clinical Medicine, Aarhus University Hospital, Denmark
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