Human hepatocyte growth factor elevates the blood platelets in nonhuman primates

Human hepatocyte growth factor (HGF) was administered to normal nonhuman primates to study its biological activities in vivo. Rhesus monkeys were treated intravenously with HGF (0.6 and 3 mg/kg) twice a day for 14 days. Before and during the treatment, the counts of red blood cells (RBC), platelets and white blood cells (WBC) were analyzed and serum levels of total protein, albumin and C-reactive protein (CRP) were measured. Body weight and temperature were also monitored during the experiment. Platelet counts began increasing on day 7. The maximum platelet increment for each monkey ranged from 18 to 84% of pre-administration levels. The differences were significant between the maximum and pre-administration platelet levels for each HGF treated monkey by paired t-test (P<0.05). No changes were observed in WBC counts, however there was a small decrease in RBC counts. Serum biochemistry showed that HGF increased total protein levels but did not affect levels of CRP, one of the acute phase proteins. There were no changes in body weight or body temperature of the HGF treated-monkeys during the observation period. These results indicate that HGF is able to increase platelet counts in nonhuman primates without significant side effects.