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Erythropoietin prevented the decreased expression of aquaporin1-3 in ureteral obstructive kidneys in juvenile rats. Pediatr Res 2022; 93:1258-1266. [PMID: 35986150 DOI: 10.1038/s41390-022-02224-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/17/2022] [Accepted: 07/18/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Urinary tract obstruction is associated with impaired renal urinary concentration; even after the release of the obstruction, patients still suffer from polyuria. It has been reported that the decreased expression of aquaporins (AQPs) is associated with postobstructive polyuria, and erythropoietin (EPO) can promote the recovery of decreased AQP2 expression induced by bilateral ureteral obstruction. However, whether EPO can promote the recovery of the expression of AQP1-3 after the release of unilateral ureteral obstruction (UUO) has not yet been reported. AIMS To investigate the effects of EPO treatment on the expression of renal AQP1-3 after the release of UUO. METHODS UUO was established in rats by 24-h temporary unilateral obstruction of renal ureters. Three days following EPO treatment, the kidneys were removed to determine the expression levels of AQP1-3, NLRP3, caspase-1, and IL-1β via semiquantitative immunoblotting and immunohistochemistry. RESULTS EPO inhibited the expression of NLRP3, caspase-1, and IL-1β; reduced plasma creatinine and urea; and promoted the recovery of AQP1-3 expression in UUO rats. CONCLUSIONS EPO treatment prevented the decreased expression of renal AQPs and the development of impaired urinary concentration capacity after the release of UUO, which may partially occur by way of anti-inflammasome effects. IMPACT EPO treatment could prevent the decreased expression of renal water transporter proteins AQP1-3 and the development of impaired renal functions, which may be associated with its anti-inflammasome effects. EPO regulated the expression of renal water transporter proteins AQP1-3, which could provide the potential for the treatment of postobstructive polyuresis. EPO treatment could be one of the effective methods by participating in multiple dimensions for patients with obstructive nephropathy.
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Chang M, Chen B, Shaffner J, Dworkin LD, Gong R. Melanocortin System in Kidney Homeostasis and Disease: Novel Therapeutic Opportunities. Front Physiol 2021; 12:651236. [PMID: 33716796 PMCID: PMC7943476 DOI: 10.3389/fphys.2021.651236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/03/2021] [Indexed: 12/30/2022] Open
Abstract
Melanocortin peptides, melanocortin receptors, melanocortin receptor accessory proteins, and endogenous antagonists of melanocortin receptors are the key components constituting the melanocortin hormone system, one of the most complex and important hormonal systems in our body. A plethora of evidence suggests that melanocortins possess a protective activity in a variety of kidney diseases in both rodent models and human patients. In particular, the steroidogenic melanocortin peptide adrenocorticotropic hormone (ACTH), has been shown to exert a beneficial effect in a number of kidney diseases, possibly via a mechanism independent of its steroidogenic activity. In patients with steroid-resistant nephrotic glomerulopathy, ACTH monotherapy is still effective in inducing proteinuria remission. This has inspired research on potential implications of the melanocortin system in glomerular diseases. However, our understanding of the role of the melanocortinergic pathway in kidney disease is very limited, and there are still huge unknowns to be explored. The most controversial among these is the identification of effector cells in the kidney as well as the melanocortin receptors responsible for conveying the renoprotective action. This review article introduces the melanocortin hormone system, summarizes the existing evidence for the expression of melanocortin receptors in the kidney, and evaluates the potential strategy of melanocortin therapy for kidney disease.
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Affiliation(s)
- Mingyang Chang
- Division of Nephrology, Department of Medicine, University of Toledo College of Medicine, Toledo, OH, United States
| | - Bohan Chen
- Division of Nephrology, Department of Medicine, University of Toledo College of Medicine, Toledo, OH, United States
| | - James Shaffner
- Division of Nephrology, Department of Medicine, University of Toledo College of Medicine, Toledo, OH, United States
| | - Lance D Dworkin
- Division of Nephrology, Department of Medicine, University of Toledo College of Medicine, Toledo, OH, United States
| | - Rujun Gong
- Division of Nephrology, Department of Medicine, University of Toledo College of Medicine, Toledo, OH, United States
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Melatonin therapy protects against renal injury before and after release of bilateral ureteral obstruction in rats. Life Sci 2019; 229:104-115. [PMID: 31100324 DOI: 10.1016/j.lfs.2019.05.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 01/31/2023]
Abstract
AIM Blockage of the urinary tract is often connected with renal function impediment, including reductions in glomerular filtration rate (GFR) and the power to control sodium as well as water elimination through urination. Melatonin, known to be the primary product of the pineal gland, prevents renal damage caused by ischemic reperfusion. However, the effects of melatonin on urinary obstruction, as well as release of obstruction induced kidney injury are still largely unknown. The aim of present study was to investigate the effect of melatonin on mediating protection against renal injury triggered from either bilateral ureteral obstruction (BUO) or BUO release (BUO-R). MAIN METHODS Adult male Sprague-Dawley rats (n = 60) were clustered into six treatment groups: sham treated-1; BUO-non-treated (24 h BUO only); BUO + melatonin; sham treated-2; BUO-48hR (24 h of BUO and then release for 2 days); and BUO-48hR + melatonin. Kidney tissues, blood and urine samples were obtained for further assessment. KEY FINDINGS It was found that melatonin treatment remarkably promoted the recovery of the handling capacity of urinary excretion of water as well as sodium in BUO and BUO-48hR models. Melatonin treatment partially inhibited inflammatory cytokine expression and the downregulation of aquaporin (AQPs, AQP-1, -2 and -3) expression in these two models. Moreover, the cytoarchitecture of BUO rats exposed to melatonin was well preserved. SIGNIFICANCE Melatonin treatment potently prevents BUO or BUO-R induced renal injury, which may be partially attributed to restoring the expression of AQPs and inhibition of inflammatory response, as well as preserving renal ultrastructural integrity.
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Gao H, Gui J, Wang L, Xu Y, Jiang Y, Xiong M, Cui Y. Aquaporin 1 contributes to chondrocyte apoptosis in a rat model of osteoarthritis. Int J Mol Med 2016; 38:1752-1758. [PMID: 27779640 PMCID: PMC5117737 DOI: 10.3892/ijmm.2016.2785] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 09/19/2016] [Indexed: 11/06/2022] Open
Abstract
Aquaporins (AQPs) have been found to be associated with a number of diseases. However, the role of AQP-1 in the pathogenesis of osteoarthritis remains unclear. We previously found that AQP-1 expression was upregulated in osteoarthritic cartilage and strongly correlated with caspase-3 expression and activity. The aim of this study was to further investigate the association of AQP-1 expression with chondrocyte apoptosis in a rat model of osteoarthritis, using RNA interference to knock down AQP-1. For this purspose, 72 male Sprague-Dawley rats were randomly assigned to 3 groups as follows: the control group not treated surgically (n=24), the sham-operated group (n=24), and the osteoarthritis group (n=24). Osteoarthritis was induced by amputating the anterior cruciate ligament and medial collateral ligament and partially excising the medial meniscus. Chondrocytes from the rats with osteoarthritis were isolated and cultured. shRNAs were used to knock down AQP-1 expression in the cultured chondrocytes. The expression of AQP-1 and caspase-3 was determined by reverse transcription-quantitative polymerase chain reaction. Caspase-3 activity was measured using a caspase-3 colorimetric assay. The rats in our model of osteoarthritis exhibited severe cartilage damage. The knockdown of AQP-1 decreased caspase-3 expression and activity in the cultured chondrocytes. In addition, the expression of AQP-1 positively correlated with caspase-3 expression and activity. Thus, the findings of our study, suggest that AQP-1 promotes caspase-3 activation and thereby contributes to chondrocyte apoptosis and to the development of osteoarthritis.
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Affiliation(s)
- Hangfei Gao
- Department of Traumatology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, P.R. China
| | - Jiancao Gui
- Department of Orthopaedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Liming Wang
- Department of Orthopaedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Yan Xu
- Department of Orthopaedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Yiqiu Jiang
- Department of Orthopaedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Mingyue Xiong
- Department of Traumatology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, P.R. China
| | - Yongguang Cui
- Department of Traumatology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, P.R. China
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Experimental evidence that preexisting chronic kidney disease is a risk factor for acute kidney injury. Kidney Res Clin Pract 2014; 33:71-2. [PMID: 26877953 PMCID: PMC4714153 DOI: 10.1016/j.krcp.2014.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 04/15/2014] [Indexed: 01/18/2023] Open
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van Rijt WG, Secher N, Keller AK, Møldrup U, Chynau Y, Ploeg RJ, van Goor H, Nørregaard R, Birn H, Frøkiaer J, Nielsen S, Leuvenink HGD, Jespersen B. α-Melanocyte stimulating hormone treatment in pigs does not improve early graft function in kidney transplants from brain dead donors. PLoS One 2014; 9:e94609. [PMID: 24728087 PMCID: PMC3984270 DOI: 10.1371/journal.pone.0094609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/17/2014] [Indexed: 01/24/2023] Open
Abstract
Delayed graft function and primary non-function are serious complications following transplantation of kidneys derived from deceased brain dead (DBD) donors. α-melanocyte stimulating hormone (α-MSH) is a pleiotropic neuropeptide and its renoprotective effects have been demonstrated in models of acute kidney injury. We hypothesized that α-MSH treatment of the recipient improves early graft function and reduces inflammation following DBD kidney transplantation. Eight Danish landrace pigs served as DBD donors. After four hours of brain death both kidneys were removed and stored for 18 hours at 4°C in Custodiol preservation solution. Sixteen recipients were randomized in a paired design into two treatment groups, transplanted simultaneously. α-MSH or a vehicle was administered at start of surgery, during reperfusion and two hours post-reperfusion. The recipients were observed for ten hours following reperfusion. Blood, urine and kidney tissue samples were collected during and at the end of follow-up. α-MSH treatment reduced urine flow and impaired recovery of glomerular filtration rate (GFR) compared to controls. After each dose of α-MSH, a trend towards reduced mean arterial blood pressure and increased heart rate was observed. α-MSH did not affect expression of inflammatory markers. Surprisingly, α-MSH impaired recovery of renal function in the first ten hours following DBD kidney transplantation possibly due to hemodynamic changes. Thus, in a porcine experimental model α-MSH did not reduce renal inflammation and did not improve short-term graft function following DBD kidney transplantation.
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Affiliation(s)
- Willem G. van Rijt
- Department of Surgery, University Medical Center Groningen, Groningen, The Netherlands
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands
- * E-mail:
| | - Niels Secher
- Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark
| | - Anna K. Keller
- Department of Urology, Aarhus University Hospital, Aarhus, Denmark
| | - Ulla Møldrup
- Department of Urology, Aarhus University Hospital, Aarhus, Denmark
| | - Yahor Chynau
- Department of Urology, Aarhus University Hospital, Aarhus, Denmark
| | - Rutger J. Ploeg
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Harry van Goor
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands
| | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Henrik Birn
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
- The Water and Salt Research Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jørgen Frøkiaer
- The Water and Salt Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Nielsen
- The Water and Salt Research Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Henri G. D. Leuvenink
- Department of Surgery, University Medical Center Groningen, Groningen, The Netherlands
| | - Bente Jespersen
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
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Mao S, Xu H, Zou L, Xu G, Wu Z, Ding Q, Jiang H. Estrogen preserves split renal function in a chronic complete unilateral ureteral obstruction animal model. Exp Ther Med 2014; 7:1555-1562. [PMID: 24926343 PMCID: PMC4043623 DOI: 10.3892/etm.2014.1663] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 03/25/2014] [Indexed: 01/14/2023] Open
Abstract
Estrogen may help to preserve renal function in chronic kidney disease. This study examined whether estrogen administration or deprivation affected the split renal function in rats subjected to chronic unilateral ureteral obstruction (UUO). Fifteen adult female Sprague-Dawley rats were randomly divided into three groups. Low- and high-estrogen groups were modeled by female castration or estrogen intraperitoneal injection, respectively, and the rats in the normal-estrogen group were untreated. Intermittent split renal function [glomerular filtration rate (GFR)] examination was performed on rats on days 2, 6 and 16 after UUO surgery via single-photon emission computed tomography (SPECT/CT). Routine hematoxylin and eosin (H&E) staining, immunohistochemistry, pathology examination and electron microscopy were performed to compare the histological differences. Low-, normal- and high-estrogen groups were successfully established (P<0.001). In the acute stage, the GFR of the contralateral healthy kidney showed a greater compensatory rise in the normal- and high-estrogen groups than in the low-estrogen group (P<0.05). In the chronic stage, the GFR of the obstructed kidney continued to decrease with the GFR of the high-estrogen group being significantly better preserved than that of the low-estrogen group (P<0.05). The GFR of the contralateral kidney compensated to the greatest extent in the high-estrogen group (P=0.01), and the total GFR was significantly superior (P<0.05). Routine H&E examination showed significant histological changes following surgery. The low-estrogen group had significant renal interstitial fibrosis compared with the normal- and high-estrogen groups (P<0.05), as observed by immunohistochemical (IHC) examination of transforming growth factor-β (TGF-β) and α-smooth muscle actin (α-SMA). Electron-microscopic (EM) examination also differentiated between groups. In conclusion, estrogen administration and deprivation significantly affected renal function. Estrogen may preserve the split renal function (GFR) in rats with chronic UUO.
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Affiliation(s)
- Shanhua Mao
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Hua Xu
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Lujia Zou
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Gang Xu
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Zhong Wu
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Qiang Ding
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Haowen Jiang
- Department of Urology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
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Gong R. Leveraging melanocortin pathways to treat glomerular diseases. Adv Chronic Kidney Dis 2014; 21:134-51. [PMID: 24602463 DOI: 10.1053/j.ackd.2013.09.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/30/2013] [Accepted: 09/30/2013] [Indexed: 12/22/2022]
Abstract
The melanocortin system is a neuroimmunoendocrine hormone system that constitutes the fulcrum in the homeostatic control of a diverse array of physiological functions, including melanogenesis, inflammation, immunomodulation, adrenocortical steroidogenesis, hemodynamics, natriuresis, energy homeostasis, sexual function, and exocrine secretion. The kidney is a quintessential effector organ of the melanocortin hormone system with melanocortin receptors abundantly expressed by multiple kidney parenchymal cells, including podocytes, mesangial cells, glomerular endothelial cells, and renal tubular cells. Converging evidence unequivocally demonstrates that the melanocortin-based therapy using the melanocortin peptide adrenocorticotropic hormone (ACTH) is prominently effective in inducing remission of steroid-resistant nephrotic syndrome caused by various glomerular diseases, including membranous nephropathy, minimal change disease and focal segmental glomerulosclerosis, suggesting a steroidogenic-independent mechanism. Mechanistically, ACTH and other synthetic melanocortin analogues possess potent proteinuria-reducing and renoprotective activities that could be attributable to direct protection of glomerular cells and systemic immunomodulation. Thus, leveraging melanocortin signaling pathways using ACTH or novel synthetic melanocortin analogues represents a promising and pragmatic therapeutic strategy for glomerular diseases. This review article introduces the biophysiology of the melanocortin hormone system with an emphasis on the kidney as a target organ, discusses the existing data on melanocortin therapy for glomerular diseases, and elucidates the potential mechanisms of action.
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Si J, Ge Y, Zhuang S, Wang LJ, Chen S, Gong R. Adrenocorticotropic hormone ameliorates acute kidney injury by steroidogenic-dependent and -independent mechanisms. Kidney Int 2013; 83:635-46. [PMID: 23325074 PMCID: PMC3612362 DOI: 10.1038/ki.2012.447] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Adrenocorticotropic hormone (ACTH) has a renoprotective effect in chronic kidney disease; however, its effect on acute kidney injury (AKI) remains unknown. In a rat model of tumor necrosis factor (TNF)–induced AKI, we found that ACTH gel prevented kidney injury, corrected acute renal dysfunction, and improved survival. Morphologically, ACTH gel ameliorated TNF-induced acute tubular necrosis, associated with a reduction in tubular apoptosis. While the steroidogenic response to ACTH gel plateaued, the kidney-protective effect continued to increase at even higher doses, suggesting steroid-independent mechanisms. Of note, ACTH also acts as a key agonist of the melanocortin system, with its cognate melanocortin 1 receptor (MC1R) abundantly expressed in renal tubules. In TNF-injured tubular epithelial cells in vitro, ACTH reinstated cellular viability and eliminated apoptosis. This beneficial effect was blunted in MC1R-silenced cells, suggesting that this receptor mediates the anti-apoptotic signaling of ACTH. Moreover, ACTH gel protected mice against cecal ligation puncture–induced septic AKI better than α-melanocyte-stimulating hormone: a protein equal in biological activity to ACTH except for steroidogenesis. Thus, ACTH has additive renoprotective actions achieved by both steroid-dependent mechanisms and MC1R-directed anti-apoptosis. ACTH may represent a novel therapeutic strategy to prevent or treat AKI.
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Affiliation(s)
- Jin Si
- Division of Kidney Disease and Hypertension, Department of Medicine, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA
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10
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Abstract
Prostanoids are prominent, yet complex, components in the maintenance of body water homeostasis. Recent functional and molecular studies have revealed that the local lipid mediator PGE2 is involved both in water excretion and absorption. The biologic actions of PGE2 are exerted through four different G-protein-coupled receptors; designated EP1-4, which couple to separate intracellular signaling pathways. Here, we discuss new developments in our understanding of the actions of PGE2 that have been uncovered utilizing receptor specific agonists and antagonists, EP receptor and PG synthase knockout mice, polyuric animal models, and the new understanding of the molecular regulation of collecting duct water permeability. The role of PGE2 in urinary concentration comprises a variety of mechanisms, which are not fully understood and likely depend on which receptor is activated under a particular physiologic condition. EP3 and microsomal PG synthase type 1 play a role in decreasing collecting duct water permeability and increasing water excretion, whereas EP2 and EP4 can bypass vasopressin signaling and increase water reabsorption through two different intracellular signaling pathways. PGE2 has an intricate role in urinary concentration, and we now suggest how targeting specific prostanoid receptor signaling pathways could be exploited for the treatment of disorders in water balance.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Li ZZ, Xing L, Zhao ZZ, Li JS, Xue R, Chandra A, Nørregaard R, Wen JG. Decrease of renal aquaporins 1-4 is associated with renal function impairment in pediatric congenital hydronephrosis. World J Pediatr 2012; 8:335-41. [PMID: 23151861 DOI: 10.1007/s12519-012-0378-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 04/23/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Renal aquaporins (AQP1-4) concentration is downregulated and is in proportion to the degree of hydronephrosis graded by ultrasound in pediatric congenital hydronephrosis (CH). However, the relationship between the expression of AQP1-4 with the changes of renal function impairment (RFI) evaluated by (99m)Tc-DTPA renal dynamic imaging is still unclear. This study aimed to investigate the relationship between AQP1-4 expression and degree of RFI in children with CH. METHODS The expression of AQP1-4 was evaluated in 45 children with unilateral ureteropelvic junction obstruction (28 boys and 17 girls, average age: 28±10 months) and 15 children undergoing nephrectomy for nephroblastoma (8 boys and 7 girls, average age: 26±8 months) by immunoblotting and immunohistochemistry. Renal function was graded into mild and severe RFI by (99m)Tc-DTPA renal dynamic imaging. RESULTS One-way analysis of variance with Bonferonni's correction showed a significantly reduced protein expression of AQP1-4 in the severe RFI group compared with those in both mild RFI group and controls (AQP1: 0.52±0.09 vs. 0.91±0.06 vs. 1.23±0.033; AQP2: 0.68±0.12 vs. 1.09±0.06 vs. 1.52±0.08; AQP3: 0.59±0.16 vs. 0.94±0.08 vs. 1.31±0.07; AQP4: 0.64±0.06 vs. 1.14±0.07 vs. 1.61±0.07; P<0.001, respectively). In kidneys with severe RFI, there was a reduction in the protein concentration of all four AQP isoforms which was more pronounced compared with those seen in kidneys with mild RFI and in the controls. CONCLUSION AQP1-4 expression is reduced in proportion with the impairment degree of renal function graded by (99m)Tc-DTPA renal dynamic imaging in human CH.
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Affiliation(s)
- Zhen-Zhen Li
- The Institute of Clinical Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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12
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Abstract
Refractory nephrotic syndrome continues to be a therapeutic challenge despite advances in immunosuppression and blockade of the renin-angiotensin-aldosterone cascade. Adrenocorticotropic hormone (ACTH), a pituitary neuroimmunoendocrine polypeptide, was widely used in the 1950s as an effective therapy for childhood nephrotic syndrome, but has since been replaced by synthetic glucocorticoid analogues. In addition to controlling steroidogenesis, ACTH also acts as an important physiological agonist of the melanocortin system. Clinical and experimental evidence now suggests that ACTH has antiproteinuric, lipid-lowering and renoprotective properties, which are not fully explained by its steroidogenic effects. ACTH therapy is effective in inducing remission of nephrotic syndrome in patients with a variety of proteinuric nephropathies, even those resistant to steroids and other immunosuppressants. This Perspectives article describes the biophysiology of ACTH, with an emphasis on its melanocortin actions, particularly in renal parenchymal cells, which could potentially explain the therapeutic effects of ACTH in nephrotic glomerulopathies.
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Affiliation(s)
- Rujun Gong
- Division of Kidney Disease and Hypertension, Department of Medicine, Rhode Island Hospital, Brown University School of Medicine, 593 Eddy Street, Providence, RI 02903, USA.
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Page S, Chandhoke V, Baranova A. Melanin and melanogenesis in adipose tissue: possible mechanisms for abating oxidative stress and inflammation? Obes Rev 2011; 12:e21-31. [PMID: 20576005 DOI: 10.1111/j.1467-789x.2010.00773.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity has become a worldwide epidemic and can lead to multiple chronic diseases. Adipose tissue is increasingly thought to play an active role in obesity-related pathologies such as insulin resistance and non-alcoholic fatty liver disease. Obesity has been strongly associated with systemic inflammation and, to a lesser degree, with oxidative stress, although the causal relationships among these factors are unclear. A recent study demonstrating an expression of the components of the melanogenic pathway and the presence of melanin in visceral adipose has raised questions regarding the possible role of melanogenesis in adipose tissue. As this study also found larger amounts of melanin in the adipose tissue of obese patients relative to lean ones, we hypothesize that melanin, a pigment known for its antioxidant and anti-inflammatory properties, may scavenge reactive oxygen species and abate oxidative stress and inflammation in adipose tissue. This review considers the evidence to support such a hypothesis, and speculates on the role of melanin within adipocytes. Furthermore, we consider whether the α-melanocyte-stimulating hormone or its synthetic analogues could be used to stimulate melanin production in adipocytes, should the hypothesis be supported in future experiments.
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Affiliation(s)
- S Page
- Department of Molecular and Microbiology, College of Science, George Mason University, Fairfax Center for Liver Diseases, Inova Fairfax Hospital, Falls Church, VA, USA
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Brzoska T, Luger TA, Maaser C, Abels C, Böhm M. Alpha-melanocyte-stimulating hormone and related tripeptides: biochemistry, antiinflammatory and protective effects in vitro and in vivo, and future perspectives for the treatment of immune-mediated inflammatory diseases. Endocr Rev 2008; 29:581-602. [PMID: 18612139 DOI: 10.1210/er.2007-0027] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alpha-MSH is a tridecapeptide derived from proopiomelanocortin. Many studies over the last few years have provided evidence that alpha-MSH has potent protective and antiinflammatory effects. These effects can be elicited via centrally expressed melanocortin receptors that orchestrate descending neurogenic antiinflammatory pathways. alpha-MSH can also exert antiinflammatory and protective effects on cells of the immune system and on peripheral nonimmune cell types expressing melanocortin receptors. At the molecular level, alpha-MSH affects various pathways implicated in regulation of inflammation and protection, i.e., nuclear factor-kappaB activation, expression of adhesion molecules and chemokine receptors, production of proinflammatory cytokines and mediators, IL-10 synthesis, T cell proliferation and activity, inflammatory cell migration, expression of antioxidative enzymes, and apoptosis. The antiinflammatory effects of alpha-MSH have been validated in animal models of experimentally induced fever; irritant and allergic contact dermatitis, vasculitis, and fibrosis; ocular, gastrointestinal, brain, and allergic airway inflammation; and arthritis, but also in models of organ injury. One obstacle limiting the use of alpha-MSH in inflammatory disorders is its pigmentary effect. Due to its preserved antiinflammatory effect but lack of pigmentary action, the C-terminal tripeptide of alpha-MSH, KPV, has been delineated as an alternative for antiinflammatory therapy. KdPT, a derivative of KPV corresponding to amino acids 193-195 of IL-1beta, is also emerging as a tripeptide with antiinflammatory effects. The physiochemical properties and expected low costs of production render both agents suitable for the future treatment of immune-mediated inflammatory skin and bowel disease, fibrosis, allergic and inflammatory lung disease, ocular inflammation, and arthritis.
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Affiliation(s)
- Thomas Brzoska
- Department of Dermatology, University of Münster, Von Esmarch-Strasse 58, D-48149 Münster, Germany
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Doi K, Hu X, Yuen PST, Leelahavanichkul A, Yasuda H, Kim SM, Schnermann J, Jonassen TEN, Frøkiaer J, Nielsen S, Star RA. AP214, an analogue of alpha-melanocyte-stimulating hormone, ameliorates sepsis-induced acute kidney injury and mortality. Kidney Int 2008; 73:1266-74. [PMID: 18354376 DOI: 10.1038/ki.2008.97] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sepsis remains a serious problem in critically ill patients with the mortality increasing to over half when there is attendant acute kidney injury. alpha-Melanocyte-stimulating hormone is a potent anti-inflammatory cytokine that inhibits many forms of inflammation including that with acute kidney injury. We tested whether a new alpha-melanocyte-stimulating hormone analogue (AP214), which has increased binding affinity to melanocortin receptors, improves sepsis-induced kidney injury and mortality using a cecal ligation and puncture mouse model. In the lethal cecal ligation-puncture model of sepsis, severe hypotension and bradycardia resulted and AP214 attenuated acute kidney injury of the lethal model with a bell-shaped dose-response curve. An optimum AP214 dose reduced acute kidney injury even when it was administered 6 h after surgery and it significantly improved blood pressure and heart rate. AP214 reduced serum TNF-alpha and IL-10 levels with a bell-shaped dose-response curve. Additionally; NF-kappaB activation in the kidney and spleen, and splenocyte apoptosis were decreased by the treatment. AP214 significantly improved survival in both lethal and sublethal models. We have shown that AP214 improves hemodynamic failure, acute kidney injury, mortality and splenocyte apoptosis attenuating pro- and anti-inflammatory actions due to sepsis.
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Affiliation(s)
- K Doi
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1268, USA
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Li C, Wang W, Summer SN, Westfall TD, Brooks DP, Falk S, Schrier RW. Molecular mechanisms of antidiuretic effect of oxytocin. J Am Soc Nephrol 2007; 19:225-32. [PMID: 18057218 DOI: 10.1681/asn.2007010029] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Oxytocin is known to have an antidiuretic effect, but the mechanisms underlying this effect are not completely understood. We infused oxytocin by osmotic minipump into vasopressin-deficient Brattleboro rats for five days and observed marked antidiuresis, increased urine osmolality, and increased solute-free water reabsorption. Administration of oxytocin also significantly increased the protein levels of aquaporin-2 (AQP2), phosphorylated AQP2 (p-AQP2), and AQP3 in the inner medulla and in the outer medulla plus cortex. Immunohistochemistry demonstrated increased AQP2 and p-AQP2 expression and trafficking to the apical plasma membrane of principal cells in the collecting duct, and increased AQP3 expression in the basolateral membrane. These oxytocin-induced effects were blocked by treatment with the vasopressin V2 receptor antagonist SR121463B, but not by treatment with the oxytocin receptor antagonist GW796679X. We conclude that vasopressin V2 receptors mediate the antidiuretic effects of oxytocin, including increased expression and apical trafficking of AQP2, p-AQP2, and increased AQP3 protein expression.
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Affiliation(s)
- Chunling Li
- Department of Medicine, University of Colorado School of Medicine, Denver, Colorado, USA
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Current World Literature. Curr Opin Nephrol Hypertens 2007; 16:52-7. [PMID: 17143072 DOI: 10.1097/mnh.0b013e32801271d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Li C, Wang W, Summer SN, Cadnapaphornchai MA, Falk S, Umenishi F, Schrier RW. Hyperosmolality in vivo upregulates aquaporin 2 water channel and Na-K-2Cl co-transporter in Brattleboro rats. J Am Soc Nephrol 2006; 17:1657-64. [PMID: 16672318 DOI: 10.1681/asn.2005121381] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
There are considerable experimental results that indicate that arginine vasopressin (AVP)-independent factors are involved in urinary concentration. This study examined the role of hyperosmolality in vivo to modulate aquaporin 2 (AQP2) and Na-K-2Cl co-transporter (NKCC2), pivotal factors in urinary concentration, in AVP-deficient Brattleboro (BB) rats. Hyperglycemia with associated hyperosmolality occurred in diabetic BB rats (BBDM). Protein abundance of AQP2 increased and was reversed by insulin in the inner medulla (IM; control 100+/-5%; BBDM 146+/-8%; BBDM+Ins 122+/-9%; P<0.001) and inner stripe of outer medulla (ISOM; control 100+/-4%; BBDM 123+/-8%; BBDM+Ins 93+/-6%; P<0.05). These results were confirmed by immunohistochemistry studies. NKCC2 rose in the ISOM but was not reversed with insulin treatment. For investigation of the role of hyperosmolality in the absence of hyperglycemia on the regulation of the expression of renal AQP and NKCC2, studies were performed with hyperosmolality that was induced by 0.5% NaCl in drinking water in BB rats. Hyperosmolality that was induced by NaCl increased significantly the protein abundance of IM AQP2 (121+/-2 versus 100+/-5%; P<0.01), ISOM AQP2 (135+/-6 versus 100+/-5%; P<0.001), cortex plus outer stripe of outer medulla AQP2 (121+/-4 versus 100+/-1%; P<0.001), ISOM NKCC2 (133+/-1 versus 100+/-4%; P<0.05), and cortex plus outer stripe of outer medulla NKCC2 (142+/-16 versus 100+/-9%; P<0.05). In conclusion, hyperosmolality, secondary to either glucose or NaCl, upregulated renal AQP2 and NKCC2 in vivo in BB rats.
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Affiliation(s)
- Chunling Li
- Department of Medicine, University of Colorado School of Medicine, 4200 East 9th Avenue, Box B173, Denver, CO 80262, USA
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