OxyFile #231

Cultured rat mesothelial cells generate hydrogen peroxide: 
a new player in peritoneal defense?


Author:  Shostak A; Pivnik E; Gotloib L

Source:  J Am Soc Nephrol 1996 Nov; 7(11):2371-8

Abstract:

This study was designed to examine whether rat peritoneal 
mesothelial cells in culture could generate hydrogen peroxide 
in different experimental conditions. Mesothelial cells, 
incubated in M-199, spontaneously released hydrogen peroxide. 
This process was significantly increased by addition of 
phorbol myristate acetate, as well as of superoxide dismutase 
to the medium, whereas it was substantially inhibited by 
catalase. Exposure of mesothelial cells to modified M-199 
medium with 1.5% glucose concentration-lactated peritoneal 
dialysis solution did not seem to interfere either with 
the spontaneous release of hydrogen peroxide, or with that 
induced by phorbol myristate acetate. Furthermore, exposure 
of mesothelial cells to the glucose (4.25%) peritoneal 
dialysis solution in Medium M-199, was coincident with 
increased hydrogen peroxide generation, which was significantly 
higher than the spontaneous release, and not far from that 
observed with phorbol myristate acetate and superoxide 
dismutase. So far, it can be inferred from this evidence 
that peritoneal mesothelial cells in culture are not only 
endowed with the capability of producing hydrogen peroxide, 
but they can also be activated to do so in a way comparable 
to that observed in neutrophils and macrophages. This attribute 
is one more indication that mesothelial cells play a relevant 
role in the peritoneal mechanism of defense against infection. 
On the other hand, continuous exposure of mesothelial cells 
to glucose-enriched fluids, as occurs in clinical continuous 
ambulatory peritoneal dialysis, may well also be at the 
origin of a process of continuous injury, resulting from 
an increased hydrogen peroxide generation.