Elevated plasma semicarbazide‐sensitive amine oxidase (SSAO) activity in Type 2 diabetes mellitus complicated by retinopathy

Abstract

SSAO activity, earlier found to be elevated in Type 1 DM, is also elevated in Type 2 DM. The SSAO family of enzymes may be involved in the development of diabetic retinopathy, possibly by catalysing the formation of toxic metabolites. A potent and specific inhibitor of human SSAO might help prevent retinopathy in Type 1 and Type 2 DM.

Determination of human serum semicarbazide-sensitive amine oxidase activity via flow injection analysis with fluorescence detection after online derivatization of the enzymatically produced benzaldehyde with 1,2-diaminoanthraquinone

“…This finding is in accordance with previous reports [6,7,[30][31][32]. Nunes et al attributed the significant increase in SSAO activity in diabetic patients to the translocation of SSAO from the tissue-bound to plasma due to alterations in arterial permeability [33].…”

“…These products are all potentially cytotoxic, e.g., formaldehyde is well known to be a major environmental risk factor, acrolein and methylglyoxal may disrupt the functions of proteins, lipids, and enzymes, and hydrogen peroxide is a major generator of oxidative stress which is commonly associated with numerous diseases [4]. The activity of serum SSAO has been reported to be increased in certain clinical conditions such as heart failure [5] and diabetes mellitus [6,7]. Also, when the activity of SSAO is high, the increased enzymatic-mediated deamination is proposed to be involved in the pathogenesis of many vascular disorders [8].…”

Plasma semicarbazide-sensitive amine oxidase activity in type 1 diabetes is related to vascular and renal function but not to glycaemia

“…Similarly in T2DM, circulating SSAO activity has been reported to be increased relative to control subjects [21][22][23] and has been found to be higher in T2DM subjects with proliferative diabetic retinopathy and/or clinically significant macular oedema. 23 Positive correlations have been described with HbA1c, 14 adiposity and dyslipidaemia.…”

“…23 Positive correlations have been described with HbA1c, 14 adiposity and dyslipidaemia. 22 Variation in glycaemia (measured as mean amplitude of glucose excursions, MAGE) in T2DM has been linked with increased oxidative stress and microvascular complications.…”

“…21,22 The levels of SSAO activity, its clinical correlates, regulatory factors and role of SSAO/VAP-1 activity in diabetes complications require further elucidation. 7,[22][23][24] Circulating SSAO activity is increased in diabetes, both in humans 22 and animals, 25 in renal disease, 26 cardiovascular disease (CVD), 12 inflammation 27 and in disseminated cancer. 28 Elevated adrenaline output, 29 which is associated with increased CVD-related morbidity and mortality, 30 may also upregulate SSAO activity.…”