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Yip T, Tse KC, Lam MF, Cheng SW, Lui SL, Tang S, Ng M, Chan TM, Lai KN, Lo WK. Risks and Outcomes of Peritonitis after Flexible Colonoscopy in CAPD Patients. Perit Dial Int 2020. [DOI: 10.1177/089686080702700517] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Objective The ISPD 2005 guidelines for peritonitis recommend antibiotic prophylaxis for patients undergoing colonoscopy with polypectomy while on continuous ambulatory peritoneal dialysis (CAPD) but there is little literature to support this recommendation. This study aimed to look into the risks and outcomes of peritonitis after colonoscopy in CAPD patients. Patients and Methods All records of flexible colonoscopy performed on our CAPD patients from January 1994 to January 2006 were retrieved. Demographic and clinical data, use of antibiotics before colonoscopy, endoscopic findings, procedure performed, and peritonitis data were analyzed. Results 77 CAPD patients underwent 97 colonoscopies. No peritonitis developed in the 18 cases where antibiotics were given before colonoscopy. Among those without antibiotic prophylaxis, 4 episodes of peritonitis occurred within 24 hours after the procedure and 1 occurred 5 days later. All responded to intraperitoneal antibiotics. Colonic biopsy and polypectomy were not associated with more peritonitis (2 in 41 with biopsy vs 3 in 38 without biopsy, p = 0.67; 1 in 30 with polypectomy vs 4 in 49 without polypectomy, p = 0.64). Conclusion The risk of peritonitis after colonoscopy without antibiotic prophylaxis was 6.3%. All peritonitis episodes responded to intraperitoneal antibiotics. Colonic biopsy or polypectomy did not appear to increase the risk of peritonitis. Although statistically not significant when compared with patients without antibiotic prophylaxis, we observed no peritonitis after colonoscopy in patients that were given antibiotics for prophylactic purposes or for other reasons. The efficacy of prophylactic antibiotics would be better defined by large randomized trials.
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Yiu WH, Li RX, Wong DWL, Wu HJ, Chan KW, Chan LYY, Leung JCK, Lai KN, Sacks SH, Zhou W, Tang SCW. Complement C5a inhibition moderates lipid metabolism and reduces tubulointerstitial fibrosis in diabetic nephropathy. Nephrol Dial Transplant 2019; 33:1323-1332. [PMID: 29294056 DOI: 10.1093/ndt/gfx336] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/07/2017] [Indexed: 02/06/2023] Open
Abstract
Background Complement C5 mediates pro-inflammatory responses in many immune-related renal diseases. Given that the C5a level is elevated in diabetes, we investigated whether activation of C5a/C5aR signalling plays a pathogenic role in diabetic nephropathy (DN) and the therapeutic potential of C5a inhibition for renal fibrosis. Methods Human renal biopsies from patients with DN and control subjects were used for immunohistochemical staining of complement C5 components. Renal function and tubulointerstitial injury were compared between db/m mice, vehicle-treated mice and C5a inhibitor-treated db/db mice. A cell culture model of tubule epithelial cells (HK-2) was used to demonstrate the effect of C5a on the renal fibrotic pathway. Results Increased levels of C5a, but not of its receptor C5aR, were detected in renal tubules from patients with DN. The intensity of C5a staining was positively correlated with the progression of the disease. In db/db mice, administration of a novel C5a inhibitor, NOX-D21, reduced the serum triglyceride level and attenuated the upregulation of diacylglycerolacyltransferase-1 and sterol-regulatory element binding protein-1 expression and lipid accumulation in diabetic kidney. NOX-D21-treated diabetic mice also had reduced serum blood urea nitrogen and creatinine levels with less glomerular and tubulointerstitial damage. Renal transforming growth factor beta 1 (TGF-β1), fibronectin and collagen type I expressions were reduced by NOX-D21. In HK-2 cells, C5a stimulated TGF-β production through the activation of the PI3K/Akt signalling pathway. Conclusions Blockade of C5a signalling by NOX-D21 moderates altered lipid metabolism in diabetes and improved tubulointerstitial fibrosis by reduction of lipid accumulation and TGF-β-driven fibrosis in diabetic kidney.
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Li B, Leung JCK, Chan LYY, Yiu WH, Li Y, Lok SWY, Liu WH, Chan KW, Tse HF, Lai KN, Tang SCW. Amelioration of Endoplasmic Reticulum Stress by Mesenchymal Stem Cells via Hepatocyte Growth Factor/c-Met Signaling in Obesity-Associated Kidney Injury. Stem Cells Transl Med 2019; 8:898-910. [PMID: 31054183 PMCID: PMC6708066 DOI: 10.1002/sctm.18-0265] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/24/2019] [Indexed: 12/12/2022] Open
Abstract
Recent advances in the understanding of lipid metabolism suggest a critical role of endoplasmic reticulum (ER) stress in obesity‐induced kidney injury. Hepatocyte growth factor (HGF) is a pleiotropic cytokine frequently featured in stem cell therapy with distinct renotropic benefits. This study aims to define the potential link between human induced pluripotent stem cell‐derived mesenchymal stem cells (iPS‐MSCs)/bone marrow‐derived MSCs (BM‐MSCs) and ER stress in lipotoxic kidney injury induced by palmitic acid (PA) in renal tubular cells and by high‐fat diet (HFD) in mice. iPS‐MSCs or BM‐MSCs alleviated ER stress (by preventing induction of Bip, chop, and unfolded protein response), inflammation (Il6, Cxcl1, and Cxcl2), and apoptosis (Bax/Bcl2 and terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labeling‐positive cells) in renal cortex of animals exposed to HFD thus mitigating histologic damage and albuminuria, via activating HGF/c‐Met paracrine signaling that resulted in enhanced HGF secretion in the glomerular compartment and c‐Met expression in the tubules. Coculture experiments identified glomerular endothelial cells (GECs) to be the exclusive source of glomerular HGF when incubated with either iPS‐MSCs or BM‐MSCs in the presence of PA. Furthermore, both GEC‐derived HGF and exogenous recombinant HGF attenuated PA‐induced ER stress in cultured tubular cells, and this effect was abrogated by a neutralizing anti‐HGF antibody. Taken together, this study is the first to demonstrate that MSCs ameliorate lipotoxic kidney injury via a novel microenvironment‐dependent paracrine HGF/c‐Met signaling mechanism to suppress ER stress and its downstream pro‐inflammatory and pro‐apoptotic consequences. stem cells translational medicine2019;8:898&910
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Chan KW, Kwong ASK, Chan GCW, Leung CPS, Yiu WH, Lui SL, Ip TP, Cowling BJ, Wong DWL, Li B, Li Y, Feng Y, Chan LY, Leung JC, Tan KCB, Wong Taam VCW, Lai KN, tang SCW. Semi-individualised Chinese Medicine Treatment for Diabetic Kidney Disease – From users’ perspectives to SCHEMATIC trial interim result and potential mechanisms. ADVANCES IN INTEGRATIVE MEDICINE 2019. [DOI: 10.1016/j.aimed.2019.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
IgA nephropathy (IgAN), a common primary glomerulonephritis worldwide, is associated with a substantial risk of progression to end-stage renal failure. The disease runs a highly variable clinical course with frequent involvement of tubulointerstitial damage. A subgroup of IgAN with proximal tubular epithelial cells (PTECs) and tubulointerstitial damage often is associated with rapid progression to end-stage renal failure. Human mesangial cell-derived mediators lead to podocyte and tubulointerstitial injury via mesangial-podocytic-tubular cross-talk. Although mesangial-podocytic communication plays a pathogenic role in podocytic injury, the implication of a podocyte-PTEC cross-talk pathway in the progression of tubulointerstitial injury in IgAN should not be underscored. We review the role of mesangial-podocytic-tubular cross-talk in the progression of IgAN. We discuss how podocytopathy in IgAN promotes subsequent PTEC dysfunction and whether tubulointerstitial injury affects the propagation of podocytic injury in IgAN. A thorough understanding of the cross-talk mechanisms among mesangial cells, podocytes, and PTECs may lead to better design of potential therapeutic options for IgAN.
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Chan GC, Wu HJ, Chan KW, Yiu WH, Zou A, Huang XR, Lan HY, Lai KN, Tang SC. N-acetyl-seryl-aspartyl-lysyl-proline mediates the anti-fibrotic properties of captopril in unilateral ureteric obstructed BALB/C mice. Nephrology (Carlton) 2018; 23:297-307. [DOI: 10.1111/nep.13000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 12/18/2016] [Accepted: 01/08/2017] [Indexed: 12/21/2022]
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Ma MK, Yap DY, Li CL, Mok MM, Chan GC, Kwan LP, Lai KN, Tang SC. WITHDRAWN: Enteric coated mycophenolate sodium combined with lowdose steroid as first line therapy in minimal change nephrotic syndrome: an open label randomized controlled study. Oncotarget 2018. [DOI: 10.18632/oncotarget.23838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Yiu WH, Wong DWL, Wu HJ, Li RX, Yam I, Chan LYY, Leung JCK, Lan HY, Lai KN, Tang SCW. Kallistatin protects against diabetic nephropathy in db/db mice by suppressing AGE-RAGE-induced oxidative stress. Kidney Int 2017; 89:386-98. [PMID: 26536000 DOI: 10.1038/ki.2015.331] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 09/05/2015] [Accepted: 09/10/2015] [Indexed: 01/03/2023]
Abstract
Kallistatin is a serine protease inhibitor with anti-inflammatory, anti-angiogenic, and anti-oxidative properties. Since oxidative stress plays a critical role in the pathogenesis of diabetic nephropathy, we studied the effect and mechanisms of action of kallistatin superinduction. Using ultrasound-microbubble-mediated gene transfer, kallistatin overexpression was induced in kidney tubules. In db/db mice, kallistatin overexpression reduced serum creatinine and BUN levels, ameliorated glomerulosclerosis and tubulointerstitial injury, and attenuated renal fibrosis by inhibiting TGF-β signaling. Additionally, downstream PAI-1 and collagens I and IV expression were reduced and kallistatin partially suppressed renal inflammation by inhibiting NF-κB signaling and decreasing tissue kallikrein activity. Kallistatin lowered blood pressure and attenuated oxidative stress as evidenced by suppressed levels of NADPH oxidase 4, and oxidative markers (nitrotyrosine, 8-hydroxydeoxyguanosine, and malondialdehyde) in diabetic renal tissue. Kallistatin also inhibited RAGE expression in the diabetic kidney and AGE-stimulated cultured proximal tubular cells. Reduced AGE-induced reactive oxygen species generation reflected an anti-oxidative mechanism via the AGE-RAGE-reactive oxygen species axis. These results indicate a renoprotective role of kallistatin against diabetic nephropathy by multiple mechanisms including suppression of oxidative stress, anti-fibrotic and anti-inflammatory actions, and blood pressure lowering.
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Chan KW, Ip TP, Kwong ASK, Lui SL, Chan GCW, Cowling BJ, Yiu WH, Wong DWL, Liu Y, Feng Y, Tan KCB, Chan LYY, Leung JCK, Lai KN, Tang SCW. Semi-individualised Chinese medicine treatment as an adjuvant management for diabetic nephropathy: a pilot add-on, randomised, controlled, multicentre, open-label pragmatic clinical trial. BMJ Open 2016; 6:e010741. [PMID: 27496229 PMCID: PMC4986085 DOI: 10.1136/bmjopen-2015-010741] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION Diabetes mellitus and diabetic nephropathy (DN) are prevalent and costly to manage. DN is the leading cause of end-stage kidney disease. Conventional therapy blocking the renin-angiotensin system has only achieved limited effect in preserving renal function. Recent observational data show that the use of Chinese medicine (CM), a major form of traditional medicine used extensively in Asia, could reduce the risk of end-stage kidney disease. However, existing clinical practice guidelines are weakly evidence-based and the effect of CM remains unclear. This trial explores the effect of an existing integrative Chinese-Western medicine protocol for the management of DN. OBJECTIVE To optimise parameters and assess the feasibility for a subsequent phase III randomised controlled trial through preliminary evaluation on the effect of an adjuvant semi-individualised CM treatment protocol on patients with type 2 diabetes with stages 2-3 chronic kidney disease and macroalbuminuria. METHODS AND ANALYSIS This is an assessor-blind, add-on, randomised, controlled, parallel, multicentre, open-label pilot pragmatic clinical trial. 148 patients diagnosed with DN will be recruited and randomised 1:1 to a 48-week additional semi-individualised CM treatment programme or standard medical care. Primary end points are the changes in estimated glomerular filtration rate and spot urine albumin-to-creatinine ratio between baseline and treatment end point. Secondary end points include fasting blood glucose, glycated haemoglobin, brain natriuretic peptide, fasting insulin, C peptide, fibroblast growth factor 23, urinary monocyte chemotactic protein-1, cystatin C, nephrin, transforming growth factor-β1 and vascular endothelial growth factor. Adverse events are monitored through self-completed questionnaire and clinical visits. Outcomes will be analysed by regression models. Enrolment started in July 2015. ETHICS AND REGISTRATION This protocol is approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (reference number UW 14-301). TRIAL REGISTRATION NUMBER NCT02488252.
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Tse KC, Li FK, Tang S, Tang CSO, Lai KN, Chan TM. Angiotensin inhibition or blockade for the treatment of patients with quiescent lupus nephritis and persistent proteinuria. Lupus 2016; 14:947-52. [PMID: 16425574 DOI: 10.1191/0961203305lu2249oa] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) reduces proteinuria and the rate of renal function deterioration in diabetic nephropathy and other glomerular diseases, but its role in quiescent lupus nephritis has not been established. We conducted a retrospective study to investigate the effects of ACEI/ARB on proteinuria and renal function in patients with persistent proteinuria (>1 g/day) despite resolution of acute lupus nephritis following immunosuppressive treatment. Fourteen out of 92 patients were included. The duration of treatment with ACEI/ARB was 52.1 ± 35.7 months. The levels of proteinuria, serum albumin, serum creatinine, systolic and diastolic blood pressure were 1.10 to 6.90 g/day, 35.8 ± 3.6 g/L, 102.54 ± 34.48 μmol/L, 137.6 ± 10.9 and 81.9 ± 9.2 mmHg at baseline. Proteinuria and serum albumin showed significant sustained improvements after 6 and 24 months of treatment. Comparison of slopes for serial proteinuria, albumin and reciprocal of serum creatinine before and after treatment showed significant improvements in six (43%), eight (57%) and two patients, respectively. At last follow-up proteinuria remained significantly lower (0.36 g/day, P = 0.043) and albumin higher (41.3 ± 2.2 g/L, P = 0.023). Eleven (78.6%) patients had proteinuria improved by >50%, and five had insignificant proteinuria at last follow-up. Systolic blood pressure was significantly reduced from 6 months onwards, but this did not correlate with proteinuria reduction. Diastolic blood pressure, serum creatinine, creatinine clearance, anti-dsDNA, C3 and haemoglobin were not altered. We conclude that ACEI/ARB effectively reduces proteinuria and improves serum albumin in patients with persistent proteinuria despite quiescent lupus nephritis.
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Guo H, Leung JCK, Chan LYY, Lui SL, Tsang AWL, Lai KN. Modulation of intra-pulmonary TGF-b expression by mycophenolate mofetil in lupus prone MRL/lpr mice. Lupus 2016; 14:583-92. [PMID: 16175929 DOI: 10.1191/0961203305lu2170oa] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the expression profile of inflammatory cytokines in the lung of lupus-prone MRL/lpr mice and evaluated the therapeutic potential of mycophenolate mofetil (MMF) in reducing pulmonary cytokines in active lupus. Eight-week old female MRL/lpr mice ( n = 20) were treated with MMF in vehicle by oral gavage. Disease control MRL/lpr mice ( n = 30) or normal control MRL mice ( n = 20) received vehicle alone. The mice were sacrificed after eight or 12 weeks of treatment. Gene expression and protein synthesis of IL-1β, MCP-1 and TGF-β1 in lung tissues were determined. We found an increase in the gene expression of IL-1β, MCP-1 and TGF-β1 in lung tissues of untreated MRL/lpr mice compared with MRL mice at either 16 weeks or 20 weeks of age. MMF treatment significantly prolonged the survival of MRL/lpr mice, down-regulated the gene expression of IL-1β, MCP-1 and TGF-β1 in lung tissues at the end of eight or 12 weeks of treatment. Protein synthesis of TGF-b1 was decreased following eight weeks of MMF treatment. We conclude that MMF treatment can reduce the TGF-b1 gene expression and protein synthesis in lung tissues of lupus-prone mice. Our findings provide experimental data suggesting a beneficial potential of MMF therapy in pulmonary involvement of lupus.
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Abstract
Diabetic nephropathy is the commonest cause of end-stage renal disease in most developed economies. Current standard of care for diabetic nephropathy embraces stringent blood pressure control via blockade of the renin-angiotensin-aldosterone system and glycemia control. Recent understanding of the pathophysiology of diabetic nephropathy has led to the development of novel therapeutic options. This review article focuses on available data from landmark studies on the main therapeutic approaches and highlights some novel management strategies.
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Chan GC, Lam B, Yap DY, Ip MS, Lai KN, Tang SC. Proteinuria is associated with sleep apnea in chronic kidney disease. Nephrol Dial Transplant 2016; 31:772-779. [DOI: 10.1093/ndt/gfv306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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Abstract
Since its first description in 1968, IgA nephropathy has remained the most common form of primary glomerulonephritis leading to chronic kidney disease in developed countries. The clinical progression varies, and consequent end-stage renal disease occurs in 30% to 40% of patients 20 to 30 years after the first clinical presentation. Current data implicate overproduction of aberrantly glycosylated IgA1 as being pivotal in the induction of renal injury. Effective and specific treatment is still lacking, and new therapeutic approaches will be developed after better understanding the disease pathogenesis.
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Leung JCK, Chan LYY, Saleem MA, Mathieson PW, Tang SCW, Lai KN. Combined blockade of angiotensin II and prorenin receptors ameliorates podocytic apoptosis induced by IgA-activated mesangial cells. Apoptosis 2016; 20:907-20. [PMID: 25808596 PMCID: PMC7101871 DOI: 10.1007/s10495-015-1117-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glomerulo-podocytic communication plays an important role in the podocytic injury in IgA nephropathy (IgAN). In this study, we examine the role of podocytic angiotensin II receptor subtype 1 (AT1R) and prorenin receptor (PRR) in podocytic apoptosis in IgAN. Polymeric IgA (pIgA) was isolated from patients with IgAN and healthy controls. Conditioned media were prepared from growth arrested human mesangial cells (HMC) incubated with pIgA from patients with IgAN (IgA-HMC media) or healthy controls (Ctl-HMC media). A human podocyte cell line was used as a model to examine the regulation of the expression of AT1R, PRR, TNF-α and CTGF by IgA-HMC media. Podocytic nephrin expression, annexin V binding and caspase 3 activity were used as the functional readout of podocytic apoptosis. IgA-HMC media had no effect on AngII release by podocytes. IgA-HMC media significantly up-regulated the expression of AT1R and PRR, down-regulated nephrin expression and induced apoptosis in podocytes. Mono-blockade of AT1R, PRR, TNF-α or CTGF partially reduced podocytic apoptosis. IgA-HMC media activated NFκB, notch1 and HEY1 expression by podocytes and dual blockade of AT1R with PRR, or anti-TNF-α with anti-CTGF, effectively rescued the podocytic apoptosis induced by IgA-HMC media. Our data suggests that pIgA-activated HMC up-regulates the expression of AT1R and PRR expression by podocytes and the associated activation of NFκB and notch signalling pathways play an essential role in the podocytic apoptosis induced by glomerulo-podocytic communication in IgAN. Simultaneously targeting the AT1R and PRR could be a potential therapeutic option to reduce the podocytic injury in IgAN.
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Lai KN. The cellular immunity and nature of IgA molecules in IgA nephropathy. CONTRIBUTIONS TO NEPHROLOGY 2015; 104:99-111. [PMID: 8325037 DOI: 10.1159/000422402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Lai KN, Leung JCK, Tang SCW. The Treatment of IgA Nephropathy. KIDNEY DISEASES 2015; 1:19-26. [PMID: 27536661 DOI: 10.1159/000381508] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 03/03/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is a very common glomerulonephritis worldwide. Nevertheless, treatment options for primary IgAN are still largely based on opinion or weak evidence. There is a lack of large randomized controlled trials (RCT) that provide a definitive immunosuppressive protocol for IgAN. The recent KDIGO Clinical Practice Guidelines for Glomerulonephritis have assigned low levels of evidence for almost all recommendations and suggestions related to this nephropathy. SUMMARY In this article, we review different treatment options and emphasize that the key to therapeutic decision-making is the assessment of an individual's prognosis. The risk of disease progression is closely related to clinical parameters such as proteinuria, hypertension, and impaired glomerular filtration rate. For patients with minor urinary abnormalities, the mainstay of treatment is long-term regular follow-up to detect renal progression and hypertension. Optimized supportive care aiming to maintain proteinuria <1 g/day is preferred in the typical patient presenting with microhematuria, significant but nonnephrotic proteinuria, hypertension, and variable degrees of renal failure. The atypical patient with overt nephritic syndrome or rapidly progressive kidney injury that represents a vasculitic form of IgAN should be treated with immunosuppression. Finally, the variant of overlapping syndrome of IgAN and lipoid nephrosis that runs a good prognosis should be treated as lipoid nephrosis. KEY MESSAGE The treatment of IgAN should be structured according to the clinical scenario.
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Tang SCW, Yiu WH, Lin M, Lai KN. Diabetic nephropathy and proximal tubular damage. J Ren Nutr 2015; 25:230-3. [PMID: 25578352 DOI: 10.1053/j.jrn.2014.10.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 10/29/2014] [Indexed: 12/12/2022] Open
Abstract
Diabetic nephropathy (DN) is a major cause of uremia in developed societies. Inflammation is emerging as an important mechanism for its pathogenesis and progression. Herein, we review 4 recently described cellular receptors that have been shown to mediate diabetic interstitial kidney disease. Peroxisome proliferator-activated receptor-γ attenuates STAT-1 activation and has shown promise in renoprotection. Its clinical utility is limited mainly by fluid retention through upregulation of sodium-hydrogen exchanger-3 and aquaporin-1 channels in the proximal tubule. The bradykinin receptor 2 of the kallikrein-kinin system has been shown to mediate diabetic kidney injury and its blockade conferred renoprotective effects in animal models of DN. The related protease-activated receptor, especially receptor 4, has recently been shown to participate in DN. Further studies are required to confirm its role. Finally, the toll-like receptor, especially TLR4 and TLR2, has been verified in multiple models to be a significant sensor of and reactor to hyperglycemia and other diabetic substrates that orchestrate interstitial inflammation in DN.
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Lim AI, Chan LYY, Tang SCW, Lai KN, Leung JCK. Albumin and glycated albumin activate KIM-1 release in tubular epithelial cells through distinct kinetics and mechanisms. Inflamm Res 2014; 63:831-9. [DOI: 10.1007/s00011-014-0757-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 07/05/2014] [Accepted: 07/08/2014] [Indexed: 01/06/2023] Open
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Lim AI, Chan LYY, Tang SCW, Yiu WH, Li R, Lai KN, Leung JCK. BMP-7 represses albumin-induced chemokine synthesis in kidney tubular epithelial cells through destabilization of NF-κB-inducing kinase. Immunol Cell Biol 2014; 92:427-35. [PMID: 24418819 DOI: 10.1038/icb.2013.106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 11/28/2013] [Accepted: 12/12/2013] [Indexed: 01/28/2023]
Abstract
Protein overload activates proximal tubule epithelial cells (PTECs) to release chemokines. Bone morphogenetic protein-7 (BMP-7) reduces infiltrating cells and tissue damage in acute and chronic renal injuries. The present study examines the inhibitory effect and related molecular mechanism of BMP-7 on chemokine and adhesion molecule synthesis by PTECs activated with human serum albumin (HSA). The expression profiles of chemokines and adhesion molecules in cultured human PTECs were screened by PCR array. Expression of CXCL1, CXCL2 and vascular cell adhesion protein 1 (VCAM-1) by PTECs was significantly upregulated by HSA and reduced by BMP-7. HSA activated both the canonical and noncanonical nuclear factor (NF)-κB pathways in PTECs, as indicated by the increased nuclear translocation of NF-κB p50 and p52 subunits. The nuclear translocation of NF-κB p52 was completely abrogated by BMP-7, whereas NF-κB p50 activation was only partially repressed. BMP-7 increased the expression of cellular inhibitor of apoptosis 1 (cIAP1), tumor necrosis factor receptor-associated factor (TRAF)2 and TRAF3, but not of NF-κB-inducing kinase (NIK) that was significantly upregulated by HSA. Silencing NIK recapitulated the partial inhibitory effect on HSA-induced chemokine synthesis by BMP-7. Complete abolishment of the chemokine synthesis was only achieved by including additional blockade of the NF-κB p65 translocation on top of NIK silencing. Our data suggest that BMP-7 represses the NIK-dependent chemokine synthesis in PTECs activated with HSA through blocking the noncanonical NF-κB pathway and partially interfering with the canonical NF-κB pathway.
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Wu HJ, Yiu WH, Li RX, Wong DWL, Leung JCK, Chan LYY, Zhang Y, Lian Q, Lin M, Tse HF, Lai KN, Tang SCW. Mesenchymal stem cells modulate albumin-induced renal tubular inflammation and fibrosis. PLoS One 2014; 9:e90883. [PMID: 24646687 PMCID: PMC3960109 DOI: 10.1371/journal.pone.0090883] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 02/05/2014] [Indexed: 02/07/2023] Open
Abstract
Bone marrow-derived mesenchymal stem cells (BM-MSCs) have recently shown promise as a therapeutic tool in various types of chronic kidney disease (CKD) models. However, the mechanism of action is incompletely understood. As renal prognosis in CKD is largely determined by the degree of renal tubular injury that correlates with residual proteinuria, we hypothesized that BM-MSCs may exert modulatory effects on renal tubular inflammation and epithelial-to-mesenchymal transition (EMT) under a protein-overloaded milieu. Using a co-culture model of human proximal tubular epithelial cells (PTECs) and BM-MSCs, we showed that concomitant stimulation of BM-MSCs by albumin excess was a prerequisite for them to attenuate albumin-induced IL-6, IL-8, TNF-α, CCL-2, CCL-5 overexpression in PTECs, which was partly mediated via deactivation of tubular NF-κB signaling. In addition, albumin induced tubular EMT, as shown by E-cadherin loss and α-SMA, FN and collagen IV overexpression, was also prevented by BM-MSC co-culture. Albumin-overloaded BM-MSCs per se retained their tri-lineage differentiation capacity and overexpressed hepatocyte growth factor (HGF) and TNFα-stimulating gene (TSG)-6 via P38 and NF-κB signaling. Albumin-induced tubular CCL-2, CCL-5 and TNF-α overexpression were suppressed by recombinant HGF treatment, while the upregulation of α-SMA, FN and collagen IV was attenuated by recombinant TSG-6. Neutralizing HGF and TSG-6 abolished the anti-inflammatory and anti-EMT effects of BM-MSC co-culture in albumin-induced PTECs, respectively. In vivo, albumin-overloaded mice treated with mouse BM-MSCs had markedly reduced BUN, tubular CCL-2 and CCL-5 expression, α-SMA and collagen IV accumulation independent of changes in proteinuria. These data suggest anti-inflammatory and anti-fibrotic roles of BM-MSCs on renal tubular cells under a protein overloaded condition, probably mediated via the paracrine action of HGF and TSG-6.
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Yiu WH, Wong DWL, Chan LYY, Leung JCK, Chan KW, Lan HY, Lai KN, Tang SCW. Tissue kallikrein mediates pro-inflammatory pathways and activation of protease-activated receptor-4 in proximal tubular epithelial cells. PLoS One 2014; 9:e88894. [PMID: 24586431 PMCID: PMC3931644 DOI: 10.1371/journal.pone.0088894] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 01/13/2014] [Indexed: 12/11/2022] Open
Abstract
Tissue kallikrein (KLK1) expression is up-regulated in human diabetic kidney tissue and induced by high glucose (HG) in human proximal tubular epithelial cells (PTEC). Since the kallikrein-kinin system (KKS) has been linked to cellular inflammatory process in many diseases, it is likely that KLK1 expression may mediate the inflammatory process during the development of diabetic nephropathy. In this study, we explored the role of KLK1 in tubular pro-inflammatory responses under the diabetic milieu. Recombinant KLK1 stimulated the production of inflammatory cytokines in PTEC via the activation of p42/44 and p38 MAPK signaling pathways. Molecular knockdown of endogenous KLK1 expression by siRNA transfection in PTEC attenuated advanced glycation end-products (AGE)-induced IL-8 and ICAM-1 productions in vitro. Interestingly, exposure of PTEC to KLK1 induced the expression of protease-activated receptors (PARs). There was a 2.9-fold increase in PAR-4, 1.4-fold increase in PAR-1 and 1.2-fold increase in PAR-2 mRNA levels. Activation of PAR-4 by a selective agonist was found to elicit the pro-inflammatory and pro-fibrotic phenotypes in PTEC while blockade of the receptor by specific antagonist attenuated high glucose-induced IL-6, CCL-2, CTGF and collagen IV expression. Calcium mobilization by the PAR-4 agonist in PTEC was desensitized by pretreatment with KLK1. Consistent with these in vitro findings, there was a markedly up-regulation of tubular PAR-4 expression in human diabetic renal cortical tissues. Together, these results suggest that up-regulation of KLK1 in tubular epithelial cells may mediate pro-inflammatory pathway and PAR activation during diabetic nephropathy and provide a new therapeutic target for further investigation.
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Yap DYH, Lai KN. The role of cytokines in the pathogenesis of systemic lupus erythematosus - from bench to bedside. Nephrology (Carlton) 2013; 18:243-55. [PMID: 23452295 DOI: 10.1111/nep.12047] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2013] [Indexed: 12/23/2022]
Abstract
The pathogenesis of systemic lupus erythematosus (SLE) entails a complex interaction between the different arms of the immune system. While autoantibodies production and immune complex deposition are cornered as hallmark features of SLE, there is growing evidence to propose the pathogenic role of cytokines in this disease. Examples of these cytokines include BLys, interleukin-6, interleukin-17, interleukin-18, type I interferons and tumour necrosis factor alpha. These cytokines all assume pivotal functions to orchestrate the differentiation, maturation and activation of various cell types, which would mediate local inflammatory process and tissue injury. The knowledge on these cytokines not only fosters our understanding of the disease, but also provides insights in devising biomarkers and targeted therapies. In this review, we focus on cytokines which have substantial pathogenic significance and also highlight the possible clinical applications of these cytokines.
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