Intrinsic cells: mesothelial cells -- central players in regulating inflammation and resolution.
BACKGROUND
Preservation of the structural and functional integrity of the peritoneum is essential to maintain the dialytic efficacy of the peritoneal membrane. Although much improvement has been made to peritoneal dialysis (PD) fluids, they remain bioincompatible, and together with peritonitis, they continue to induce peritoneal inflammation and fibrosis.


METHODS
This article reviews the putative factors that mediate mesothelial cell inflammation during PD, and the mechanisms by which mesothelial cells attempt to regulate and resolve peritoneal inflammation.


RESULTS
The mesothelium is the first line of defense to foreign particles and chemicals in the peritoneal cavity. Constant exposure of the mesothelium to the bioincompatible constituents of PD solutions results in denudation of the mesothelium and loss of the peritoneal cavity's protective layer. Detached mesothelial cells in PD solutions have the capacity to replenish the mesothelial layer through their ability to migrate and attach to areas of denudation. Mesothelial cells synthesize a plethora of growth factors, matrix proteins, and proteoglycans that aid in the reparative process and regulate the formation of chemotactic gradients that are essential for infiltration of leukocytes to sites of injury.


CONCLUSIONS
Far from being bystanders in peritoneal function, mesothelial cells have been shown to play a dynamic role in peritoneal homeostasis and immunoregulation. Studies have highlighted the potential use of mesothelial cells in gene therapy and cell transplantation, both of which may provide novel therapeutic strategies for the preservation of the peritoneum during PD.
Yung
Susan
S
Department of Medicine, University of Hong Kong, Hong Kong SAR, PR China. ssyyung@hkucc.hku.hk
Chan
Tak Mao
TM
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D015314:Dialysis Solutions / Q000009:adverse effects; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D010538:Peritonitis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D011509:Proteoglycans / Q000378:metabolism; D020127:Recovery of Function
D015314:Dialysis Solutions; D006025:Glycosaminoglycans; D011509:Proteoglycans