Vascular complications, including ischaemic cardiomyopathy, are the major causes of death in old diabetic patients. Chronic
inflammation due to high IL-6 production occurs in type 2 diabetes (NIDDM) and atherosclerosis. High levels of IL-6 are associated
with hyperglycaemia, dyslipidemia and provoke insulin resistance. In ageing and inflammation, IL-6 affects Metallothionein
(MT) homeostasis, which in turn is involved in zinc turnover. Zinc deficiency is an usual event in ageing, inflammation, type
2 diabetes and atherosclerosis. No genetic study exists on MT polymorphisms in NIDDM-atherosclerotic patients. The aim of
the present study is to screen a single nucleotide polymorphism in the promoter region of the MT2A gene in relation to inflammation
(IL-6) and plasma zinc in NIDDM-atherosclerotic patients. The -209 A/G MT2A polymorphism is associated with chronic inflammation
(higher plasma levels of IL-6), hyperglycaemia, enhanced HbA1c and more marked zinc deficiency in AA than AG genotype carrying
patients. Analysing patients and controls subdivided in AA and AG genotypes, significant interactions existed between disease
status and genotypes for glucose and zinc. AA patients are more at risk of developing NIDDM in association with atherosclerosis
(
p = 0.0015 odds ratio = 2.617) and its complications, such as ischaemic cardiomyopathy (
p = 0.0050 odds ratio = 12.6). In conclusion, high levels of IL-6 unmask the phenotypes (higher insulin resistance and zinc
deficiency) in relation to the genotypes with subsequent risk of developing ischaemic cardiomyopathy in NIDDM-atherosclerotic
patients carrying AA genotype. Hence, the novel -209A/G MT2A polymorphism may be a further useful tool for the prevention,
diagnosis and therapy of these combined pathologies in the elderly.
Keywords atherosclerosis - elderly - inflammation - MT2A polymorphism - type 2 diabetes - zinc