Ezetimibe reduces plant sterol accumulation and favorably increases platelet count in sitosterolemia

Abstract

Objective: To assess if ezetimibe (EZE), a sterol-absorption inhibitor, improves platelet (PLT) count and size relative to its effect on plasma plant sterol (PS) in patients with sitosterolemia (STSL).

Study design: Patients with STSL (5 males, 3 females, 16-56 years of age) receiving EZE intervention as part of their routine care participated in this study. EZE was discontinued for 14 weeks (off) and then resumed for another 14 weeks (on). Hematology variables along with plasma and red blood cells (RBC) PS and total cholesterol (TC) levels were measured at the end of each phase.

Results: EZE increased PLT count (23% ± 9%) and decreased mean PLT volume (MPV; 10% ± 3%, all P < .05). In patients off EZE, PLT counts inversely correlated (r = -0.96 and r = -0.91, all P < .01) with plasma and RBC PS to TC ratio (PS/TC), and MPV positively correlated (r = 0.91, P = .03 and r = 0.93, P = .02) with plasma and RBC PS/TC. EZE reduced plasma and RBC sitosterol (-35% ± 4% and -28% ± 3%), total PS (-37% ± 4% and -28% ± 3%, all P < .0001) levels, and PS/TC (-27% ± 4% and -28% ± 4%, P < .01).

Conclusions: EZE reduces plasma and RBC PS levels, while increasing PLT count and decreasing MPV, and thereby may reduce the risk for bleeding in STSL. Plasma PS levels and ABCG5/ABCG8 genes should be analyzed in patients with unexplained hematologic abnormalities.

Trial registration: ClinicalTrials.gov NCT01584206.

Figure 1

Plasma and RBC total cholesterol (TC), sitosterol and total plant sterols (PS) in patients with STSL (n = 8) after 14 weeks off ezetimibe (Off EZE) and 14 weeks on ezetimibe (On EZE). Data are presented as mean ± SEM. *: P <.05; **: P <.01; ***: P <.0001. Total PS is the sum of sitosterol, campesterol, stigmasterol and brassicasterol values.

Figure 2

A and B, Correlations of PLT counts and MPV with plasma PS/TC. C, Correlation of PLT counts with plasma PS/TC (Off EZE, n = 7, one patient who had the highest PLT counts was an outlier and not included). D, Correlation of MPV with plasma PS/TC (baseline, n = 5).