High glucose and hyperosmolality stimulate hepatocyte growth factor secretion from cultured human mesangial cells

Hepatocyte growth factor is a recently cloned potent mitogen to hepatocytes, but its extrahepatic roles are not completely defined. It causes proliferation of endothelial and epithelial cells implicating potential action in the glomerulus. We aimed to determine whether cultured human mesangial cells secrete hepatocyte growth factor and the effect of high glucose conditions. Mesangial cells were isolated from the normal cortex of a child's kidney. After differential glomerular sieving and trypsin digestion of glomeruli, mesangial cells were cultured in 20% fetal calf serum/RPMI. Glucose concentration in the medium was adjusted to 5 mmol/l, 11 mmol/l, 25 mmol/l or 5 mmol/l/20 mmol/l mannitol to correct for osmolality. After 0, 24, 48, 72 h incubation, hepatocyte growth factor was measured in the supernatant by enzyme immuno assay using recombinant hepatocyte growth factor and monoclonal antibodies to human hepatocyte growth factor. Hepatocyte growth factor was secreted by cultured mesangial cells. High glucose and hyperosmolar conditions caused a 100-200% increase in hepatocyte growth factor secretion at 48-72 h (p = 0.001). Hepatocyte growth factor secretion at 48 h in 5 mmol/l glucose was 16.46 +/- 1.09 ng/ml (mean +/- SEM), 11 mmol/l glucose: 32.98 +/- 4.54, 25 mmol/l glucose: 33.32 +/- 7.89, 5 mmol/l glucose/20 mmol/l mannitol: 34.05 +/- 3.64; at 72 h in 5 mmol/l glucose: 23.92 +/- 2.85 ng/ml, 11 mmol/l glucose: 28.26 +/- 2.03, 25 mmol/l glucose: 62.04 +/- 12.2, 5 mmol/l glucose/20 mmol/l mannitol: 45.76 +/- 6.25. Trypan blue exclusion demonstrated membrane integrity.(ABSTRACT TRUNCATED AT 250 WORDS)