The influence of insulin-dependent diabetes mellitus (IDDM) duration on superoxide anion and hydrogen peroxide production by polymorphonuclear neutrophils

Abstract

We address the question whether oxygen metabolism of polymorphonuclear neutrophils (PMN) is influenced by disease duration in patients with insulin-dependent diabetes mellitus (IDDM). PMN were isolated from patients with IDDM of various durations and from healthy controls. We measured PMN production of superoxide anions (O 2 −) by cytochrome c reduction (see Babior, B.M. et al. (1973) J. Clin. Invest. 52, 741–746) and PMN production of hydrogen peroxide (H 2O 2) by phenol red oxygenation (see Pick, E. (1980) J. Immunol. Methods 38, 161–169) in three groups of IDDM patients subdivided according to disease duration (group A: IDDM less than 10 years; group B: IDDM of 10–15 years; group C: IDDM of more than 15 years) and in control healthy subjects (group H). Unstimulated O 2 − production in all IDDM patients was not statistically different from control values (A: 4.3 ± 0.4 nmol/10 6 PMN per 30 min; B: 4.1 ± 0.2 nmol/10 6 PMN per 30 min; C: 4.9 ± 0.9 nmol/10 6 PMN per 30 min; and H: 3.5 ± 0.2 nmol/10 6 PMN per 30 min, respectively). In contrast, stimulated O 2 − production was significantly lower in both patients with 10–15 years, and patients with more than 15 years, duration of IDDM than in controls (B: 25.7 ± 2.5 nmol/10 6 PMN per 30 min; C: 21.1 ± 3.4 nmol/10 6 PMN per 30 min and H: 42.2 ± 1.1 nmol/10 6 PMN per 30 min, respectively) correlating with disease duration ( r = − 0.44, P < 0.033). The stimulated O 2 − production in patients with less than 10 years duration of IDDM (A: 35.7 ± 1.9 nmol/10 6 PMN per 30 min) was slightly lower than in controls. H 2O 2 production of unstimulated PMN (A: 4.0 ± 0.5 nmol/10 6 PMN per 30 min; B: 4.4 ± 0.8 nmol/10 6 PMN per 30 min and C: 4.4 ± 1.0 nmol/10 6 PMN per 30 min, respectively) was much higher than those in controls. In contrast, stimulated H 2O 2 production did not differ statistically from the value noticed in healthy subjects. The results obtained might indicate that production of H 2O 2 by unstimulated cells is increased in diabetic patients while generation of O 2 − by stimulated neutrophils is markedly impaired, suggesting that toxic oxygen species production might be influenced by disease duration.