NDT Advance Access published online on November 23, 2007
Nephrology Dialysis Transplantation, doi:10.1093/ndt/gfm553
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High glucose decreases collagenases expression and increases TIMP expression in cultured human peritoneal mesothelial cells
1Department of Internal Medicine, 2Department of Surgery, College of Medicine, Brain Korea 21, Yonsei University, Seoul, Korea, 3Nephrology and Dialysis Unit, Department of Internal Medicine, The Affiliated Hospital, YanBian University Medical College, JiLin, China, 4Department of Internal Medicine, College of Medicine, Ewha Womans University, Seoul, and 5Division of Nephrology, Department of Internal Medicine, Kwandong University College of Medicine, Koyang, Korea
Correspondence and offprint requests to: Shin-Wook Kang, Yonsei University College of Medicine, Department of Internal Medicine, 134 Shinchon-Dong Seodaemoon-Gu, Seoul, Korea, 120-752. Email: kswkidney{at}yumc.yonsei.ac.kr
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Abstract |
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Background. Peritoneal fibrosis (PF), a serious problem in long-term continuous ambulatory peritoneal dialysis (CAPD) patients, is characterized by extracellular matrix (ECM) accumulation which results from an imbalance between the synthesis and the degradation of ECM components. Previous studies have demonstrated that ECM synthesis is increased in human peritoneal mesothelial cells (HPMCs) under high glucose conditions, but the effects of high glucose on degradative pathways have not been fully explored. This study was undertaken to elucidate the effects of high glucose on these proteolytic processes in cultured HMPCs.
Methods. HPMCs were isolated from human omentum and were exposed to 5.6 mM glucose (NG), 5.6 mM glucose +34.4 mM mannitol (NG + M), or 40 mM glucose (HG) with or without PKC inhibitor (PKCi). Real-time PCR and western blot were performed to determine collagenases (MMP-1, -8 and -13) and TIMPs (TIMP-1 and -2) mRNA and protein expression, respectively. The individual activities of collagenases in culture media were determined by ELISA.
Results. Types I and III collagen protein expression were significantly increased in HG-conditioned media compared to NG media (P < 0.05). The MMP-1, -8 and -13/GAPDH mRNA ratios were significantly lower in HPMCs exposed to HG medium compared to NG cells by 64, 52 and 37%, respectively, and their protein expression by 76, 42 and 49%, respectively, in HG- vs NG-conditioned media. The activities of collagenases in HG-conditioned media were also significantly lower than those in NG media (P < 0.05). In contrast, HG significantly increased TIMPs mRNA ratios and protein expression in HPMCs. These changes in collagenase and TIMP expression induced by HG were abrogated upon pre-treatment with PKCi.
Conclusion. In conclusion, impaired matrix degradation may contribute to ECM accumulation in PF.
Keywords: collagenases; high glucose; mesothelial cells; peritoneal fibrosis; TIMPs
The authors wish it to be known that, in their opinion, the first two authors contributed equally to this work.
Received for publication: 7. 1.07
Accepted in revised form: 19. 7.07