Plasma level of mitochondrial coupling factor 6 increases in patients with coronary heart disease.

Background: The aim of the present study was to investigate alterations in the plasma level of coupling factor 6 (CF6), a novel endogenous inhibitor of prostacyclin, in patients with coronary heart disease.

Methods And Results: In total, 35 patients with coronary heart disease and 20 age-matched healthy subjects were examined. Plasma levels of CF6 and 6-keto-prostaglandin (PG)F(1a) (a stable metabolite of prostacyclin) were measured using radioimmunoassay. The plasma level of CF6 was significantly increased in patients (254.1+/-29.8 pg/ml vs 219.4 +/-36.7 pg/ml in controls, p<0.0001), whereas that of 6-keto-PGF(1a) was significantly decreased (23.4 +/-2.3 pg/ml vs 26.1+/-4.5 pg/ml in controls, p=0.001). Moreover, after percutaneous transluminal coronary angioplasty (PTCA) and stent therapy, the level of CF6 was further increased by 30% to 330.4+/-26.0 pg/ml, and that of 6-keto-PGF (1a) was decreased by 42% to 13.5+/-2.0 pg/ml, compared with baseline (all p<0.01). Univariate analysis showed a significant result that the plasma level of CF6 was inversely correlated with that of 6-keto-PGF(1a) in the patients. The plasma ratio of CF6 to 6-keto-PGF(1a) was 8.4 in the control group and that in patients with coronary heart disease was increased to 24.4 after the therapy from 10.9 before therapy.

Conclusions: The results suggest that an increased CF6 level may be responsible in part for the decreased prostacyclin level observed in patients with coronary heart disease, in particular after PTCA and stent therapy. As a potential risk factor for coronary heart disease, CF6 might have important clinical significance.