Proteomic characterization of EPCs and CECs “in vivo” from acute coronary syndrome patients and control subjects

CD34+ circulating cells display signs of immune activation in patients with acute coronary syndrome

Bone marrow-derived endothelial progenitor cells (EPC) are released into the peripheral blood in situations of vascular repair/angiogenesis. Regulation of vascular repair and angiogenesis by EPC depends not only on the number of circulating EPC but also on their functionality. As endothelial cells can act as antigen-presenting cells in coronary artery disease (CAD), we postulated that EPC can be immune activated here as well. CD34⁺-EPC were isolated from peripheral blood of patients with ST-elevation myocardial infarction (STEMI, n = 12), non-STEMI/unstable angina (UA, n = 15), and stable CAD (SA, n = 18). Expression of HLA-DR, adhesion and costimulatory molecules by isolated CD34⁺-EPC were compared with levels in healthy controls (n = 18). There were no significant differences in VCAM-1 and CD80 expression by peripheral circulating CD34⁺-EPC between the four groups, yet expression of CD86 was highest in UA (p < 0.05). ICAM-1 expression was lowest in SA (p < 0.01). CD34⁺-EPC constitutively expressed HLA-DR across all groups. Of note, patients pretreated with HMG-CoA reductase inhibitors exhibited lower expression of VCAM-1 by CD34⁺-EPC throughout all patient groups; furthermore, statins significantly limited ex vivo-induced upregulation of ICAM-1 by TNF-alpha. To the best of our knowledge, this is the first study to examine the expression of immune markers in peripheral circulating CD34⁺-EPC ex vivo. We demonstrate that CD34⁺-EPC display different patterns of adhesion and costimulatory molecules in various states of CAD. Expression levels were affected by pretreatment with statins. Hence, immune activity of peripheral circulating CD34⁺ cells might play a pathophysiologic role in evolution of CAD.

Hemoglobin A1c is associated with severity of coronary artery stenosis but not with long term clinical outcomes in diabetic and nondiabetic patients with acute myocardial infarction undergoing primary angioplasty

Background

Acute myocardial infarction (AMI) patients with type 2 diabetes mellitus are known to present with multiple vessel lesions during coronary angiography. The underlying mechanism remains elusive and there is a shortage of serum prediction markers. In this study, we investigate the relationship between admission HbA_1c and severity of coronary artery stenosis and subsequent prognosis in AMI patients with or without diabetes.

Research design and methods

We measured admission HbA_1c, and vessel scores based on the number of diseased coronary vessels with significant stenosis in 628 patients diagnosed with AMI. Simple and multi-regression analysis were performed to investigate the correlation between HbA_1c and the severity of coronary artery stenosis. Major adverse cardiovascular events (MACE), including new-onset myocardial infarction, acute heart failure and cardiac death, were documented during the follow-up. 272 non-DM participants and 137 DM participants were separated into two groups based on HbA_1c levels for survival analysis during a 2-year follow up.

Results

448 non-DM patients and 180 DM patients were included in the initial observational analysis. 272 non-DM patients and 137 DM patients were included in the follow-up survival analysis. The admission HbA_1c level was found to be significantly positively correlated to the number of affected vessels suffering from significant coronary artery stenosis both in DM (R square = 0.012; 95% CI 0.002 to 0.623, P = 0.049) and non DM patients (R square = 0.025; 95% CI 0.009 to 0.289, P = 0.037). Kaplan–Meier survival analysis revealed no significant difference with regard to different HbA_1c levels either in DM or non-DM patients at the end of follow-up.

Conclusions

In patients with AMI, admission HbA_1c is an important predictor for the severity of coronary artery stenosis in non-DM and DM patients. Further studies are needed to determine whether longer term follow-up could further identify the prognosis effect of HbA_1c on MACE.

Recent developments in proteomic methods and disease biomarkers

Proteomic methodologies for identification and analysis of biomarkers have gained more attention during recent years and have evolved rapidly. Identification and detection of disease biomarkers are important to foresee outbreaks of certain diseases thereby avoiding surgery and other invasive and expensive medical treatments for patients. Thus, more research into discovering new biomarkers and new methods for faster and more accurate detection is needed. It is often difficult to detect and measure biomarkers because of their low concentrations and the complexity of their respective matrices. Therefore it is hard to find and validate methods for accurate screening methods suitable for clinical use. The most recent developments during the last three years and also some historical considerations of proteomic methodologies for identification and validation of disease biomarkers are presented in this review.

Improving cardiovascular outcomes in rheumatic diseases: therapeutic potential of circulating endothelial progenitor cells

Patients with Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) have a significantly increased risk of cardiovascular disease (CVD). The reason for this is unclear but may be due, at least in part, to the failure of endothelial repair mechanisms. Over the last 15 years there has been much interest in the mechanisms of endothelial renewal and its potential as a therapy for CVD. In the circulation there are two distinct populations of cells; myeloid angiogenic cells (MACs) which augment repair by the paracrine secretion of angiogenic factors, and outgrowth endothelial cells (OECs) which are true endothelial progenitor cells (EPCs) and promote vasculogenesis by differentiating into mature endothelium. There are marked abnormalities in the number and function of these cells in patients with RA and SLE. Inflammatory cytokines including interferon-alpha (IFNα) and tumour-necrosis factor alpha (TNFα) both impair MAC and OEC function ex vivo and may therefore contribute to the CVD risk in these patients. Whilst administration of mononuclear cells, MACs and other progenitors has improved cardiovascular outcomes in the acute setting, this is not a viable option in chronic disease. The pharmacological manipulation of MAC/OEC function in vivo however has the potential to significantly improve endothelial repair and thus reduce CVD in this high risk population.