Abstract: Objective To investigate the relationship between plasma homocysteine (Hcy), Kv1.3 channel and cardiac troponinI (cTnI) in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods According to the level of Hcy, 80 STEMI patients were divided into STEMI with Hhcy group (Hcy > 15 μmol/L, n=41) and control group (STEMI group, Hcy≤15 μmol/L, n=39). The Hcy, blood lipid and cTnI were detected with automatic biochemistry analyzer, respectively. Peripheral lymphocytes were isolated by ficoll density gradient centrifugation. Real-time PCR was used to detect mRNA expression of Kv1.3, and Western blot assay was used to detect protein expression of Kv1.3. Results cTnI concentrations were obviously higher in STEMI with Hhcy group than those in STEMI group（μg/L： 22.997 ± 5.880 vs. 12.881 ± 6.343； P＜ 0.01）. Multiple linear regression analysis showed that age, gender, hypertension, diabetes mellitus, smoking, family history, total cholesterol (TC), triglyceride (TG), high density lipoprotein- cholesterol (HDL- C) and low density lipoprotein-cholesterol (LDL-C) had no obvious influence on Hcy (P＞ 0.05). The relative expression levels of Kv1.3 mRNA and protein were significantly higher in STEMI with Hhcy group (1.35±0.14, 0.85±0.12) than those in STEMI group (1.00± 0.07, 0.64± 0.05, P＜ 0.05). Moreover, there was a positive relation between Hcy level and the mRNA and protein expression of Kv1.3 channel (r=0.299, r=0.542, P＜ 0.05). There was a positive relation between protein expression levels of Kv1.3 channel and cTnI (r=0.644, P＜ 0.05). Conclusion Our results support that Hcy could exacerbate the concentration of cTnI through playing an important role in the Kv1.3 mRNA and protein expression in lymphocytes.

Key words: myocardial infarction, hyperhomocysteinemia, Kv1.3 potassium channel, lymphocytes, troponin I, acute ST-segment elevation myocardial infarction