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Serum spermidine oxidase activity in patients with insulin-dependent diabetes mellitus and microvascular
G Seghieri1, A Gironi, M Niccolai
1Sezione di Diabetologia, Spedali Riuniti, Pistoia, Italy.
Abstract:
Metabolism of polyamines (spermidine and spermine) is known to be strictly related to the growth processes of eukaryotic cells. Since cell replication processes appear altered in insulin-dependent diabetes mellitus (IDDM), especially when associated with its microvascular complications, the aim of this study was measuring serum spermidine oxidase activity (SOA), a key enzyme in the metabolic pathway of polyamines, in 47 patients with IDDM as compared with 63 healthy control subjects matched for age and sex. Mean SOA levels +/- SD were significantly lower in IDDM patients (177.4 +/- 57.2 mu kat/l) than in controls (247.6 +/- 68.1 mu kat/l; p less than 0.001), being SOA inversely related with daily insulin dose. SOA was moreover significantly higher (but similar to controls) in the group with increased urinary albumin excretion rate (AER persistently greater than 20 micrograms/min); (n = 17; 213.1 +/- 62.6 mu kat/l) in comparison with normoalbuminuric subjects (n = 30; 156.6 +/- 43.5 mu kat/l; F = 21.78; p = 0.0001). SOA was correlated with AER (r = 0.45; p = 0.001), independently of age, duration of disease, serum creatinine, body weight, blood pressure and metabolic control, as shown by a multiple regression analysis model (p = 0.003). Presence of background retinopathy was not associated with modified levels of SOA, which was conversely higher, although not significantly, in the patients with proliferative retinal lesions. In conclusion serum SOA is deeply altered in IDDM patients, being markedly reduced in the whole group of patients and conversely independently increased up to the mean values of controls in presence of increased AER or advanced retinopathy.
Insights
Serum spermidine oxidase activity (SOA) is significantly lower in patients with insulin-dependent diabetes mellitus (IDDM). However, SOA increases with microvascular complications like albuminuria and retinopathy in IDDM patients.
Area of Science:
- Biochemistry
- Endocrinology
- Metabolic Research
Background:
- Polyamines, including spermidine and spermine, are crucial for eukaryotic cell growth and replication.
- Cell replication is often altered in insulin-dependent diabetes mellitus (IDDM), particularly with microvascular complications.
Purpose of the Study:
- To measure serum spermidine oxidase activity (SOA), a key enzyme in polyamine metabolism.
- To compare SOA levels in patients with IDDM versus healthy controls.
- To investigate the relationship between SOA and IDDM complications.
Main Methods:
- Serum spermidine oxidase activity (SOA) was measured in 47 IDDM patients and 63 healthy controls.
- Statistical analyses, including t-tests and multiple regression, were used to compare groups and identify correlations.
- Factors like age, disease duration, and metabolic control were considered.
Main Results:
- Mean SOA levels were significantly lower in IDDM patients (177.4 ± 57.2 μkat/l) compared to controls (247.6 ± 68.1 μkat/l; p < 0.001).
- SOA was inversely related to daily insulin dose.
- SOA was significantly higher in IDDM patients with increased urinary albumin excretion rate (AER) and correlated with AER independently of other factors.
- SOA levels were higher in patients with proliferative retinopathy.
Conclusions:
- Serum SOA is significantly altered in IDDM patients, generally reduced overall.
- Increased AER and advanced retinopathy in IDDM are associated with normalized or increased SOA levels, independent of disease duration or metabolic control.
- These findings suggest a complex role for polyamine metabolism in the pathogenesis of IDDM complications.