Endothelial progenitor cells, endothelial cell dysfunction and much more: observations from cardiac syndrome X

Frequency of Helicobacter pylori and cytotoxine associated gene A antibodies in patients with cardiac syndrome X

Background:

Cardiac syndrome X (CSX) is a condition in which patients have the pain of angina despite normal coronary angiogram. Recently, Helicobacter pylori (H. pylori) bacteria has been associated with CSX. However, there is no obvious data about the frequency of its virulent strain (cytotoxine associated gene A: CagA) in patients with CSX. We surveyed the frequency of H. pylori and CagA antibodies in patients with cardiac syndrome X and healthy controls.

Materials and Methods:

Plasma samples from 100 CSX patients (61 females and 39 males; mean age: 51.8 ± 12.3 years) and 100 healthy controls (61 females and 39 males; mean age: 48.9 ± 6.3 years) were tested for the presence of IgG antibody to H. pylori using enzyme linked immunosorbent assay (ELISA) method. Also, infected patients were determined by the presence of IgG antibody to CagA by ELISA method. Statistical analysis was carried out using chi-square test and independent samples T-test.

Results:

Ninety two percent (92/100) of patients were anti-H. pylori positive (anti-H. pylori+), while only 56.0% (56/100) of control group were anti-H. pylori+ (P<0.01). However, prevalence of anti-CagA positive (anti- CagA+) in H. pylori infected- CSX patients and control groups were 59.8% (55/92) and 60.7% (34/56), respectively (P>0.05).

Conclusion:

Thus, due to the high frequency of anti-H. pylori in CSX patients, and the probable causative effect of chronic infection in vascular diseases, it is suggested that H. pylori has a probable role in the pathogenesis of CSX.

Moderate-to-high-intensity training and a hypocaloric Mediterranean diet enhance endothelial progenitor cells and fitness in subjects with the metabolic syndrome

A reduction in EPC (endothelial progenitor cell) number could explain the development and progression of atherosclerosis in the MetS (metabolic syndrome). Although much research in recent years has focused on the Mediterranean dietary pattern and the MetS, the effect of this diet with/without moderate-to-high-intensity endurance training on EPCs levels and CrF (cardiorespiratory fitness) remains unclear. In the present study, the objective was to assess the effect of a Mediterranean diet hypocaloric model with and without moderate-to-high-intensity endurance training on EPC number and CrF of MetS patients. Thus 45 MetS patients (50–66 years) were randomized to a 12-week intervention with the hypocaloric MeD (Mediterranean diet) or the MeDE (MeD plus moderate-to-high-intensity endurance training). Training included two weekly supervised sessions [80% MaxHR (maximum heart rate); leg and arm pedalling] and one at-home session (65–75% MaxHR; walking controlled by heart rate monitors). Changes in: (i) EPC number [CD34+KDR+ (kinase insert domain-containing receptor)], (ii) CrF variables and (iii) MetS components and IRH (ischaemic reactive hyperaemia) were determined at the end of the study. A total of 40 subjects completed all 12 weeks of the study, with 20 in each group. The MeDE led to a greater increase in EPC numbers and CrF than did the MeD intervention (P≤0.001). In addition, a positive correlation was observed between the increase in EPCs and fitness in the MeDE group (r=0.72; r2=0.52; P≤0.001). Body weight loss, insulin sensitivity, TAGs (triacylglycerols) and blood pressure showed a greater decrease in the MeDE than MeD groups. Furthermore, IRH was only improved after the MeDE intervention. In conclusion, compliance with moderate-to-high-intensity endurance training enhances the positive effects of a model of MeD on the regenerative capacity of endothelium and on the fitness of MetS patients.

Endothelial progenitor cells: identity defined?

In the past decade, researchers have gained important insights on the role of bone marrow (BM)-derived cells in adult neovascularization. A subset of BM-derived cells, called endothelial progenitor cells (EPCs), has been of particular interest, as these cells were suggested to home to sites of neovascularization and neoendothelialization and differentiate into endothelial cells (ECs) in situ, a process referred to as postnatal vasculogenesis. Therefore, EPCs were proposed as a potential regenerative tool for treating human vascular disease and a possible target to restrict vessel growth in tumour pathology. However, conflicting results have been reported in the field, and the identification, characterization, and exact role of EPCs in vascular biology is still a subject of much discussion. The focus of this review is on the controversial issues in the field of EPCs which are related to the lack of a unique EPC marker, identification challenges related to the paucity of EPCs in the circulation, and the important phenotypical and functional overlap between EPCs, haematopoietic cells and mature ECs. We also discuss our recent findings on the origin of endothelial outgrowth cells (EOCs), showing that this in vitro defined EC population does not originate from circulating CD133⁺ cells or CD45⁺ haematopoietic cells.