Aggressive Cholesterol Lowering Normalizes Atherosclerosis Regression in Clonal Hematopoiesis.

BACKGROUND -: Clonal hematopoiesis (CH) has emerged as an important risk factor for atherosclerotic cardiovascular disease (ACVD). Mouse studies have established a causal role of CH in atherosclerosis progression and have defined macrophage inflammatory responses as a key underlying mechanism. We undertook the present study to assess the hypothesis that ongoing inflammation would impede atherosclerosis regression in ( ) CH mice.

METHODS AND RESULTS -: Chimeric or control bone marrow was transplanted into mice and, following 13-16 weeks of Western diet-induced atherosclerosis progression, cholesterol was lowered either moderately (to 200-300 mg/dl) or markedly (to 100 mg/dl). With moderate cholesterol lowering there was impaired regression in CH mice compared to controls. However, with marked cholesterol lowering, regression was similar in CH and control mice.Two mechanisms of low-density lipoprotein (LDL) lowering-induced suppression of inflammation in plaques were implicated: 1) reversal of increased proliferation, DNA damage and Absent in Melanoma 2 (AIM2) inflammasome activation specifically in macrophages and 2) markedly increased macrophage triggering receptor expressed on myeloid cells 2 (TREM2), c-myc expressing macrophages in both and control mice.

CONCLUSIONS -: Aggressive LDL lowering reverses inflammasome activation and induces pro-resolving changes in macrophages in CH, halting atherosclerosis progression and promoting features of plaque stabilization. These findings suggest that aggressive LDL cholesterol lowering could effectively reverse ACVD risk in individuals with clonal hematopoiesis.