Cilostazol Attenuates PCSK9 Expression in Vascular Smooth Muscle Cells in an Experimental Model of Metabolic Syndrome

Introduction: Metabolic syndrome (MetS) increases cardiovascular risk and is associated with elevated PCSK9 levels, which promote LDL receptor (LDLr) degradation. Cilostazol (CZ), in addition to its antiplatelet, vasodilatory, and antioxidant properties, may reduce PCSK9 expression. However, the effects of CZ on PCSK9 expression in vascular smooth muscle cells (VSMCs) under MetS conditions remain unclear. This study investigated the effects of CZ in VSMCs from Zucker fa/fa rats.

Methods: Rats were euthanized in Italy in 2000, when ethical approval was not required. VSMCs were isolated from lean Zucker rats (LZR group) and obese Zucker rats (OZR group) (n=8/group). VSMCs were incubated with CZ (1–200μM) and assessed for cell viability, proliferation (MTT), migration (wound-healing), and reactive oxygen species production (ROS), (DCF-DA). PCSK9 expression was evaluated by qPCR and western blot with CZ (10–100 μM), LPS (20 ng/mL) or DMSO. Untreated cells served as basal control. Data are mean ± SEM and were analyzed by Student’s t-test or one-way ANOVA with Bonferroni’s test, as appropriate (p<0.05).

Results: Cell proliferation was significantly reduced in the presence of CZ (50, 100, and 200 μM) at 24, 48 and 72h in VSMCs from LZR, besides reducing proliferation in OZR VSMCs at 72 h (p<0.05). Meanwhile, no differences in cell viability were observed. Further, CZ (50 μM) was able to reduce cell migration in OZR, while it did not affect LZR VSMCs. At the same concentration, CZ was also able to decrease ROS production in both LZR and OZR VSMCs (p<0.05). Regarding PCSK9 expression in VSMCs from LZR and OZR, LPS-induced upregulation was attenuated by CZ at both mRNA and protein levels (p<0.05).

Conclusion: These findings demonstrate, for the first time, that CZ reduces VSMC proliferation, migration, and ROS production, while downregulating PCSK9 expression in VSMCs from both lean and obese Zucker rats.

Financial support: CNPq, CAPES, PROPPI-UFF, FAPERJ.