Delayed intervention with AGE inhibitors attenuates the progression of diabetes-accelerated atherosclerosis in diabetic apolipoprotein E knockout mice

Aims/hypothesis Formation of AGEs is increased in the diabetic milieu, which contributes to accelerated atherogenesis. We studied whether delayed treatment with AGE-inhibiting compounds, alagebrium chloride and pyridoxamine dihydrochloride, affected established atherosclerosis in experimental diabetes in comparison with the angiotensin-converting enzyme inhibitor, quinapril. Methods Streptozotocin-induced diabetic male Apoe ⁻/⁻ mice (n = 24 per group) received, by oral gavage, from week 10 to 20 of diabetes: no treatment; alagebrium (1 mg kg⁻¹ day⁻¹); pyridoxamine (1 g/l in drinking water); or quinapril (30 mg kg⁻¹ day⁻¹). Atherosclerotic lesion area (en face analysis) was evaluated for all groups. Results Delayed intervention with alagebrium decreased plaque area in the diabetic Apoe ⁻/⁻ mice compared with untreated mice (total plaque area: alagebrium 10.6 ± 1.6%, untreated, 15.1 ± 1.5%, p < 0.05). This anti-atherosclerotic effect was comparable with that achieved with quinapril (quinapril 8.4 ± 1.4%, vs untreated, p < 0.05). Pyridoxamine also attenuated plaque development in diabetic mice (5.7 ± 1.2% vs untreated 11.9 ± 1.1%, p < 0.05). The anti-atherosclerotic effect conferred by alagebrium and quinapril was associated with a significant reduction in vascular oxidative stress and circulating AGEs and methylglyoxal, although preformed AGEs were not removed from the vascular wall with either delayed intervention. Conclusions/interpretation Inhibition of AGE accumulation, using a delayed intervention with alagebrium or pyridoxamine, significantly attenuated the progression of established diabetes-associated atherosclerosis, similar to results obtained with quinapril. These findings provide further evidence that blockade of AGE-mediated pathways may present a novel therapy for the prevention of atherosclerosis in diabetes.