Distinct effects of rosuvastatin and rosuvastatin/ezetimibe on senescence markers of CD8+ T cells in patients with type 2 diabetes mellitus: a randomized controlled trial

ObjectivesChronic low-grade inflammation is widely recognized as a pathophysiological defect contributing to β-cell failure in type 2 diabetes mellitus (T2DM). Statin therapy is known to ameliorate CD8+ T cell senescence, a mediator of chronic inflammation. However, the additional immunomodulatory roles of ezetimibe are not fully understood. Therefore, we investigated the effect of statin or statin/ezetimibe combination treatment on T cell senescence markers.MethodsIn this two-group parallel and randomized controlled trial, we enrolled 149 patients with T2DM whose low-density lipoprotein cholesterol (LDL-C) was 100 mg/dL or higher. Patients were randomly assigned to either the rosuvastatin group (N=74) or the rosuvastatin/ezetimibe group (N=75). The immunophenotype of peripheral blood mononuclear cells and metabolic profiles were analyzed using samples from baseline and post-12 weeks of medication.ResultsThe fractions of CD8+CD57+ (senescent CD8+ T cells) and CD4+FoxP3+ (Treg) significantly decreased after intervention in the rosuvastatin/ezetimibe group (−4.5 ± 14.1% and −1.2 ± 2.3%, respectively), while these fractions showed minimal change in the rosuvastatin group (2.8 ± 9.4% and 1.4 ± 1.5%, respectively). The degree of LDL-C reduction was correlated with an improvement in HbA1c (R=0.193, p=0.021). Changes in the CD8+CD57+ fraction positively correlated with patient age (R=0.538, p=0.026). Notably, the fraction change in senescent CD8+ T cells showed no significant relationship with changes in either HbA1c (p=0.314) or LDL-C (p=0.592). Finally, the ratio of naïve to memory CD8+ T cells increased in the rosuvastatin/ezetimibe group (p=0.011), but not in the rosuvastatin group (p=0.339).ConclusionsWe observed a reduction in senescent CD8+ T cells and an increase in the ratio of naive to memory CD8+ T cells with rosuvastatin/ezetimibe treatment. Our results demonstrate the immunomodulatory roles of ezetimibe in combination with statins, independent of improvements in lipid or HbA1c levels.