Biomedical Research

Both insulin-like growth factor-I (IGF-I) and erythropoietin (EPO) have been found to stimulate erythropoiesis, and IGF-I levels are decreased in patients with chronic renal fail-ure (CRF). Decreased IGF-I levels might contribute to the progression of anemia of CRF. However, no studies have examined the effects of rHuEPO therapy on plasma IGF-I levels and Hb concentration in predialysis diabetic patients with CRF and anemia. Therefore, we investigated the effects of rHuEPO treatment on plasma IGF-I levels and Hb concentrations in patients with diabetes and anemia of CRF. Seven patients with type 2 diabetes mellitus accompanied by advanced nephropathy (renal failure stage) were studied. The mean (±SE) age was 62.6±6.2yrs. Serum creatinine and creatinine clearance levels were 327.1±44.2 μmol/L and 0.261±0.022 ml/s, respectively. Re-combinant human EPO (rHuEPO) was subcutaneously infused into the abdomen for 4 weeks at a flow rate of 6,000 IU/2.5ml/week using a portable infusion pump. Plasma EPO levels were increased from 19.4±2.2 IU/L to 69.6±16.9 IU/L 1 week after the start of rHuEPO administration, and were maintained at a steady state. Plasma IGF-I lev-els at time 0 decreased to 72.7±8.4 μg/L compared with age-matched diabetic patients with-out nephropathy (166.0±15.5 μg/L). Plasma IGF-I levels were increased 1-3 weeks after the start of rHuEPO administration, followed by an increase in Hb concentrations 3-4 weeks after rHuEPO administration. We have therefore hypothesized that rHuEPO administration increases plasma IGF-I levels followed by Hb concentrations. These findings suggest that rHuEPO treatment has a stimulatory effect on IGF-I production, and that increases in IGF-I might be a good indica-tor of improved Hb concentrations.

Author(s): Motoi Sohmiya and Yoko Sohmiya
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