Metformin-induced PCSK9 inhibition further decreases LDL-C following statin treatment in patients with coronary artery disease and without diabetes

In vitro investigations have established metformin's capacity to downregulate PCSK9 expression, suggesting a potential beneficial effect on atherogenic lipoprotein particles when combined with metformin therapy. Our objective was to assess whether metformin could mitigate statin-induced adverse effects on PCSK9, thereby improving lipid profiles in patients with coronary artery disease (CAD) but without diabetes. Employing an open-label, placebo-controlled, randomized trial, we randomized patients with CAD but without diabetes into CLA (Cholesterol-Lowering Agents alone: atorvastatin+/-ezetimibe, n=38) and Met+CLA groups (metformin plus CLA, n=33) at a 1:1 ratio. The primary endpoint was the therapeutic impact of one-month metformin combination treatment on LDL-C and PCSK9 levels. Baseline LDL-C and PCSK9 levels were 76.18 mg·dL -1 and 80.54 ng·mL -1 , respectively. After one month, metformin significantly reduced LDL-C (-20.81%, P<0.001), enabling 72% of patients to attain guideline-recommended LDL-C goals. Noteworthy reductions in PCSK9 levels (-15.03%, P<0.001) were observed. Moreover, Met+CLA markedly reduced LDL particle number more than CLA alone (-10.65% vs 1.45%, P=0.009), primarily due to diminished small-dense LDL particle count. Mechanistically, our study demonstrated metformin's inhibition of statin-induced PCSK9 expression in human hepatocellular cells. In summary, a one-month metformin combination regimen reduced LDL-C levels in patients with CAD but without diabetes by inhibiting PCSK9 expression.