Effect of lactate and bicarbonate on human peritoneal mesothelial cells, fibroblasts and vascular endothelial cells, and the role of basic fibroblast growth factor.
BACKGROUND
In patients on long-term continuous ambulatory peritoneal dialysis (CAPD), peritoneal dysfunction may occur due to loss of peritoneal mesothelial cells, peritoneal fibrosis and neovascularization. Lactate, long used as a buffer in peritoneal dialysates, has been substituted by bicarbonate in recent years. However, their effects on the peritoneum of CAPD patients are unknown. This study investigated the influence of lactate and bicarbonate on peritoneal dysfunction in CAPD patients.


METHODS
The mitochondrial activity of human peritoneal mesothelial cells (HPMCs) and their expression of basic fibroblast growth factor (bFGF) were studied after culture under various conditions. We also assessed the mitochondrial-activating effect of the supernatant of those cultures on human peritoneal fibroblasts (HPFBs) and human umbilical vein endothelial cells (HUVECs) and the effect of recombinant human bFGF on the mitochondrial activity of HPFBs and HUVECs. We used the WST-1 assay to determine mitochondrial activity in HPMC.


RESULTS
At pH 7.4, the mitochondrial activity of HPMCs was lowest in a medium containing 40 mM (Lac), intermediate in a lactate (15 mM) plus bicarbonate (25 mM) medium (Lac/Bic), and highest in a 40 mM bicarbonate medium (Bic). In culture supernatant, the increase of bFGF was: Lac > Lac/Bic > Bic. Mitochondrial activation of HPFBs and HUVECs was stimulated by HPMC culture supernatants in the following decreasing order: Lac > Lac/Bic > Bic. The effects of these supernatants were suppressed by a bFGF-neutralizing antibody, while recombinant bFGF caused concentration-dependent mitochondrial activation in HPFBs and HUVECs.


CONCLUSIONS
The role of bFGF in peritoneal fibrosis and neovascularization may be important. A bicarbonate-containing medium is better than a lactate-containing medium for preserving cell viability in HPMCs and preventing bFGF expression by these cells.
Ogata
Satoshi
S
Department of Internal Medicine, National Kure Medical Center, Hiroshima, Japan.
Naito
Takayuki
T
Yorioka
Noriaki
N
Kiribayashi
Kei
K
Kuratsune
Masatoshi
M
Kohno
Nobuoki
N
D001639:Bicarbonates / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D015314:Dialysis Solutions / Q000378:metabolism / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology; D004847:Epithelial Cells / Q000187:drug effects* / Q000473:pathology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects*; D005355:Fibrosis; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D010529:Peritoneal Cavity / Q000166:cytology; D010531:Peritoneal Dialysis, Continuous Ambulatory; D013778:Tetrazolium Salts; D014471:Umbilical Veins / Q000166:cytology
C110656:2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium; D001639:Bicarbonates; D017077:Culture Media, Conditioned; D015314:Dialysis Solutions; D013778:Tetrazolium Salts; D016222:Fibroblast Growth Factor 2; D019344:Lactic Acid