Effects of pitavastatin versus atorvastatin on the peripheral endothelial progenitor cells and vascular endothelial growth factor in high-risk patients: a pilot prospective, double-blind, randomized study

Abstract

Background: Circulating endothelial progenitor cells (EPCs) reflect endothelial repair capacity and may be a significant marker for the clinical outcomes of cardiovascular disease. While some high-dose statin treatments may improve endothelial function, it is not known whether different statins may have similar effects on EPCs.This study aimed to investigate the potential class effects of different statin treatment including pitavastatin and atorvastatin on circulating EPCs in clinical setting.

Methods: A pilot prospective, double-blind, randomized study was conducted to evaluate the ordinary dose of pitavastatin (2 mg daily) or atorvastatin (10 mg daily) treatment for 12 weeks on circulating EPCs in patients with cardiovascular risk such as hypercholesterolemia and type 2 diabetes mellitus (T2DM). Additional in vitro study was conducted to clarify the direct effects of both statins on EPCs from the patients.

Results: A total of 26 patients (19 with T2DM) completed the study. While the lipid-lowering effects were similar in both treatments, the counts of circulating CD34+KDR+EPCs were significantly increased (from 0.021 ± 0.015 to 0.054 ± 0.044% of gated mononuclear cells, P < 0.05) only by pitavastatin treatment. Besides, plasma asymmetric dimethylarginine level was reduced (from 0.68 ± 0.10 to 0.53 ± 0.12 μmol/L, P < 0.05) by atorvastatin, and plasma vascular endothelial growth factor (VEGF) level was increased (from 74.33 ± 32.26 to 98.65 ± 46.64 pg/mL, P < 0.05) by pitavastatin. In the in vitro study, while both statins increased endothelial nitric oxide synthase (eNOS) expression, only pitavastatin increased the phosphorylation of eNOS in EPCs. Pitavastatin but not atorvastatin ameliorated the adhesion ability of early EPCs and the migration and tube formation capacities of late EPCs.

Conclusions: While both statins similarly reduced plasma lipids, only pitavastatin increased plasma VEGF level and circulating EPCs in high-risk patients, which is probably related to the differential pleiotropic effects of different statins.

Trial registration: This trial is registered at ClinicalTrials.gov, NCT01386853.

Figure 1

Representative flow cytometry analysis for quantifying the number of circulating endothelial progenitor cells (EPCs).

Figure 2

Percentage of stained dual-positive endothelial progenitor cells (EPCs) of gated mononuclear cells analyzed by flow cytometry. There are no differences of (A) CD34⁺CD133⁺ EPCs and (B) CD133⁺KDR⁺ EPCs between pitavastatin and atorvastatin groups. (C) The levels of circulating CD34⁺KDR⁺ EPCs are significantly increased after 12 week treatment with pitavastatin. *: p < 0.05 compared with baseline.

Figure 3

Pitavastatin significantly increased the adhesion function of early endothelial progenitor cells (EPCs). Early EPCs were pretreated with pitavastatin and atorvastatin (10⁻⁷ M) for 24 hours. The number of adhesion of early EPC was analyzed by fibronectin-adhesion assay (n = 12) (A). The effects of pitavastatin and atorvastatin on the proliferation of late EPCs, analyzed by MTT assay after treatment with different doses of statins for 24 hours (B), migration (C) and capillary tube formation (D). Data are presented as mean ± SD in each experiment; n = 4. *: p < 0.05 compared with control.

Figure 4

Pitavastatin increased the endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) expression in human endothelial progenitor cells (EPCs). Late EPCs were pretreated with pitavastatin and atorvastatin (10⁻⁷ M) for 24 hours. Both of pitavastatin and atorvastatin increased significantly total form of eNOS activation analyzed by Western blotting (A). Ratio of phosphorylated eNOS over total eNOS significantly increased only in late EPCs after co-incubated with pitavasatin (B). Pitavastatin (10⁻⁷ M) increased significantly expression of VEGF in early EPCs analyzed by Western blotting (C). *: P < 0.05 was considered significant.

Figure 5

Schematic representation of the possible mechanism of effects of pitavastatin and atorvastatin on endothelial progenitor cells (EPCs). Atorvastatin decreased serum asymmetric dimethylarginine (ADMA) and pitavastatin increased serum vascular endothelial growth factor (VEGF), both increasing the expression of total form endothelial nitric oxide synthase (eNOS) in late EPCs. Only pitavastatin could increase circulating EPCs number and function via enhancing eNOS activity.