Implications of reverse cholesterol transport: recent studies.

INTRODUCTION: There is a strong epidemiological relationship between high density lipoproteins and atherosclerotic coronary vascular disease (ASCVD). The process of reverse cholesterol transport (RCT) has been hypothesized to help explain this relationship. The corollary that raising HDL should reduce ASCVD is also drawn from this relationship. In recent years, the metabolism of HDL has become better understood. A hypothetical process for explaining RCT has been superimposed on the currently understood HDL metabolic pathways. METHODS: Outline of HDL metabolism and the superimposed RCT process. Literature review of studies of persons with genetic defects, HDL cholesterol raising clinical trials, Mendelian randomization studies and treatments with molecules that mimic HDL. CONCLUSIONS: Mutation studies of ABCA1, LCAT and SR-B1 genes in humans showed expected variations in HDLC but little association with ASCVD and there was no significant association between HDLC and ASCVD in Mendelian randomization studies. Elevations in HDLC due to treatment with niacin and cholesteryl ester transport protein inhibitors in randomized trials raised HDLC but did not significantly reduce risk of ASCVD. Treatment with molecules that mimic HDL did not seem to reduce ASCVD. Thus, recent evidence does not seem to support RCT as currently proposed. This hypothesis seems to need substantial revision.

Cardiac stem cells in patients with ischaemic cardiomyopathy (SCIPIO): initial results of a randomised phase 1 trial.

BACKGROUND: c-kit-positive, lineage-negative cardiac stem cells (CSCs) improve post-infarction left ventricular (LV) dysfunction when administered to animals. We undertook a phase 1 trial (Stem Cell Infusion in Patients with Ischemic cardiOmyopathy [SCIPIO]) of autologous CSCs for the treatment of heart failure resulting from ischaemic heart disease. METHODS: In stage A of the SCIPIO trial, patients with post-infarction LV dysfunction (ejection fraction [EF] ≤40%) before coronary artery bypass grafting were consecutively enrolled in the treatment and control groups. In stage B, patients were randomly assigned to the treatment or control group in a 2:3 ratio by use of a computer-generated block randomisation scheme. 1 million autologous CSCs were administered by intracoronary infusion at a mean of 113 days (SE 4) after surgery; controls were not given any treatment. Although the study was open label, the echocardiographic analyses were masked to group assignment. The primary endpoint was short-term safety of CSCs and the secondary endpoint was efficacy. A per-protocol analysis was used. This study is registered with ClinicalTrials.gov, number NCT00474461. FINDINGS: This study is still in progress. 16 patients were assigned to the treatment group and seven to the control group; no CSC-related adverse effects were reported. In 14 CSC-treated patients who were analysed, LVEF increased from 30·3% (SE 1·9) before CSC infusion to 38·5% (2·8) at 4 months after infusion (p=0·001). By contrast, in seven control patients, during the corresponding time interval, LVEF did not change (30·1% [2·4] at 4 months after CABG vs 30·2% [2·5] at 8 months after CABG). Importantly, the salubrious effects of CSCs were even more pronounced at 1 year in eight patients (eg, LVEF increased by 12·3 ejection fraction units [2·1] vs baseline, p=0·0007). In the seven treated patients in whom cardiac MRI could be done, infarct size decreased from 32·6 g (6·3) by 7·8 g (1·7; 24%) at 4 months (p=0·004) and 9·8 g (3·5; 30%) at 1 year (p=0·04). INTERPRETATION: These initial results in patients are very encouraging. They suggest that intracoronary infusion of autologous CSCs is effective in improving LV systolic function and reducing infarct size in patients with heart failure after myocardial infarction, and warrant further, larger, phase 2 studies. FUNDING: University of Louisville Research Foundation and National Institutes of Health.