LIPOPROTEIN(A) AND PROLIFERATIVE DIABETIC-RETINOPATHY IN TYPE-II DIABETES-MELLITUS - A ROLE ISOFORMS WITH LOW-MOLECULAR-WEIGHT

Apolipoprotein(a) [apo(a)] displays a remarkable genetic heterogeneity of which the physiopathologic mechanisms are yet unknown. Its homolog y with plasminogen also suggests a pro-thrombotic role. To investigate whether or not lipoprotein(a) [Lp(a)] concentration and/or apo(a) iso forms correlate with the severity of diabetic retinopathy (DR), 113 Ty pe II diabetic patients were studied. By fluorescein angiography, 3 cl asses of DR were considered: ''null'' (40 subjects), ''non-proliferati ve'' (37 subjects) and ''proliferative'' (36 subjects). Apo(a) isoform s were detected by a capillary Western Blotting technique, resulting i n the identification of 21 apo(a) isoforms with molecular weight (MW) varying from 400 to 775 kDa, Lp(a) plasma concentration did not correl ate with the degree of DR (15.6 mg/dl in ''null'', 17.8 mg/dl in ''non -proliferative'' and 20.6 mg/dl in ''proliferative'' DR group, p=0.399 ). On the contrary, in subjects with proliferative DR there was a sign ificant prevalence (65%) of low MW apo(a) isoforms (cut-off between 64 0 and 655 kDa), as compared to null DR (26%, p<0.01) and to non-prolif erative DR (35%, p<0.05). In conclusion, low MW apo(a) isoforms could represent another possible biological marker of the genetic risk for t he development and progression of retinal diabetic microangiopathy.