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.

Objectives: Chronic 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.

Methods: In 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.

Results: The fractions of CD8+CD57+ (senescent CD8+ T cells) and CD4+FoxP3+ (T) 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, =0.021). Changes in the CD8+CD57+ fraction positively correlated with patient age (R=0.538, =0.026). Notably, the fraction change in senescent CD8+ T cells showed no significant relationship with changes in either HbA1c (=0.314) or LDL-C (=0.592). Finally, the ratio of naïve to memory CD8+ T cells increased in the rosuvastatin/ezetimibe group (=0.011), but not in the rosuvastatin group (=0.339).

Conclusions: We 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.