Erythrocyte spermidine levels in IDDM patients.

OBJECTIVES: To evaluate whether erythrocyte levels of polyamines spermidine and spermine (expressed in nmol/ml packed erythrocytes [PRBCs]) are modified in insulin-dependent diabetes mellitus (IDDM) and are associated with the presence of retinopathy or nephropathy. RESEARCH DESIGN AND METHODS: We studied erythrocyte spermidine and spermine levels in 38 IDDM patients with or without persistent microalbuminuria (urinary albumin excretion rate [AER] between 20 and 200 micrograms/min), macroalbuminuria (AER greater than 200 micrograms/min), or retinopathy compared with 60 sex- and age-matched control subjects. RESULTS: Mean +/- SD erythrocyte spermine content was similar in both diabetic (9.7 +/- 5.5 nmol/ml PRBCs) and control (8.8 +/- 3.5 nmol/ml PRBCs) subjects, whereas spermidine was higher in diabetic (19.1 +/- 7.2 nmol/ml PRBCs) than in control (14.5 +/- 4 nmol/ml PRBCs, P = 0.0007) subjects. Moreover, spermidine was significantly higher in the groups with microalbuminuria (n = 11, 22.5 +/- 9.2 nmol/ml PRBCs) and macroalbuminuria (n = 4, 22.2 +/- 5.7 nmol/ml PRBCs) than in both normoalbuminuric (n = 23, 16.9 +/- 5.6 nmol/ml PRBCs) and control (F = 9.78, P = 0.0001) subjects, and correlated with log AER (r = 0.41, P = 0.009). Similarly, proliferative retinopathy was associated with a significant increase in spermidine (n = 5, 20 +/- 7 nmol/ml PRBCs compared with control subjects [P = 0.0009]). CONCLUSIONS: Our data suggest that erythrocyte spermidine content is increased in IDDM patients associated with both diabetic nephropathy and advanced retinopathy.