Homocysteine, cysteine, folate and vitamin B₁₂ status in type 2 diabetic patients with chronic kidney disease

Background: Hyperhomocysteinemia (hHcy) is a risk factor in the progression of chronic kidney disease (CKD). In type 2 diabetes (T2D), hHcy is strongly associated with increased risk of cardiovascular disease. Vitamin B₁₂ and folic acid supplementation have been reported to lower homocysteine (tHcy) levels, but no data on plasma tHcy, cysteine (Cys), folate and vitamin B₁₂ levels in T2D-CKD patients are reported. Procedures: tHcy and Cys levels were analyzed in 178 T2D-CKD patients by high performance liquid chromatography (HPLC) with fluorescence detection. In addition, we determined folate and vitamin B₁₂ levels using a chemiluminescence method. Results: tHcy and Cys levels were increased in T2D patients, and this rise positively correlated with the CKD stage (P 12 levels were lower, except at stage IV. We did not find any correlation between B-vitamins and levels of tHcy and Cys, regardless of the CKD stage. Conclusions: This is the first study reporting tHcy, Cys and B-vitamins status in T2D-CKD patients. Although limited to our cohort of 178 patients, our findings could be helpful in clarifying the conflicting literature regarding B-vitamins supplementation. Further studies are necessary before any Hcy-lowering therapy can be safely established in T2D-CKD subjects.