Steven Haine

A maximal exercise bout increases the number of circulating CD34+/KDR+ endothelial progenitor cells in healthy subjects. Relation with lipid profile

Mobilization of bone marrow-derived endothelial progenitor cells (EPC) might explain exercise-induced improvement of endothelial function. We assessed whether a maximal exercise bout could alter the number of circulating EPC in healthy subjects and whether this effect is related to their cardiovascular risk profile. Additionally, we investigated possible mediators of this effect, namely nitric oxide (NO) bioavailability and vascular endothelial growth factor (VEGF) release. Healthy subjects (group 1, n = 11; group 2, n = 14) performed a symptom-limited cardiopulmonary exercise test on a bicycle ergometer. Numbers of CD34+/kinase insert domain receptor (KDR)+ cells were determined by flow-cytometric analysis, either after magnetic separation of CD34+ cells (group 1) or starting from whole blood (group 2). Serum concentrations of VEGF and NO metabolites were measured by using ELISA. Following exercise, EPC increased by 76% (15.4 +/- 10.7 cells/ml vs. 27.2 +/- 13.7 cells/ml; P = 0.01) in group 1 and by 69% in group 2 (30.9 +/- 14.6 cells/ml vs. 52.5 +/- 42.6 cells/ml; P = 0.03). The increase in EPC correlated positively with LDL and total cholesterol/HDL ratio and negatively with peak oxygen consumption and oxygen consumption at anaerobic threshold. VEGF levels increased with exercise, with a strong trend toward significance (P = 0.055). NO levels remained unchanged. The present study demonstrates that a maximal bout of exercise induces a significant shift in CD34+ cells toward CD34+/KDR+ cells. This response was larger in subjects with a less favorable lipid profile.

Quantification of circulating endothelial progenitor cells: A methodological comparison of six flow cytometric approaches

OBJECTIVES The validity of endothelial progenitor cells as biomarkers and their therapeutic potential depend on the accuracy of techniques used for enumeration. This study assessed the agreement between 6 flow cytometric methods and a CFU assay used for EPC quantification. METHODS Two blood samples were obtained from 30 healthy volunteers (60 samples). CD34+/VEGFR2+ cells were analyzed with flow cytometry, starting from whole blood (A-C) or PBMC (D-F), using different gating strategies: A: lymphocyte gating; B and D: exclusion of autofluorescent cells (CD3 negative selection); C and E: exclusion of autofluorescence and cell aggregates (pulse shape analysis by FSCarea/FSCpeak); F: exclusion of autofluorescence, cell aggregates and non-nucleated cells (Draq 5). PBMC were cultured under endothelial cell conditions to assess CFU numbers. RESULTS Moderate agreement was found between methods B-C and D-E (ICC 0.647 and 0.530). Comparison of methods B-D and C-E showed poor agreement (ICC 0.178 and 0.249). This was also the case for techniques that considerably differed with regard to gating strategies (A-B, A-F, B-F). CFU numbers did not correlate with flow cytometric quantification (all p>0.05). CONCLUSIONS Agreement between methods for EPC quantification is moderate to poor, which may explain apparent controversies in literature. Although each protocol is highly reproducible, this study cautions against comparing study results gathered with different enumeration techniques.

Current perspective of pathophysiological and interventional effects on endothelial progenitor cell biology: Focus on Pi3K/AKT/eNOS pathway

For more than a decade, endothelial progenitor cells (EPCs) have been implicated in cardiovascular homeostasis. EPCs are believed to reside within the bone marrow in close contact with surrounding stromal cells, and, under stimulation of pro-inflammatory cytokines, EPCs are mobilized out of the bone marrow. Hereafter circulating EPCs home to peripheral tissues, undergoing further proliferation and differentiation. Under certain pathophysiologic conditions this process seems to be blunted, resulting in a reduced capacity of EPCs to engage in vasculogenesis at sites of endothelial injury or tissue ischemia. In this review, we focus on the effects of traditional cardiovascular risk factors on EPC biology and we explore whether pharmacological, dietary and lifestyle interventions can favorably restore EPC mobilization, differentiation, homing and angiogenic properties. Because the PI3K/Akt/eNOS pathway plays a pivotal role in the process of EPC mobilization, migration and homing, we specifically emphasize the involvement of PI3K, Akt and eNOS in EPC biology under these different (patho)physiologic conditions. (Pre)clinically used drugs or lifestyle interventions that have been shown to ameliorate EPC biology are reviewed. These treatment strategies remain attractive targets to restore the regenerative capacity of EPCs in cardiovascular diseases.

Coronary microvascular dysfunction after myocardial infarction: increased coronary zero flow pressure both in the infarcted and in the remote myocardium is mainly related to left ventricular filling pressure

Objective: To investigate the underlying mechanisms of a decreased coronary flow reserve after myocardial infarction (MI) by analysing the characteristics of the diastolic hyperaemic coronary pressure–flow relationship. Design: Prospective study. Setting: Tertiary care hospital. Patients: 68 patients with a recent MI and 27 patients with stable angina pectoris (AP; control group). Main outcome measures: The intercept with the pressure axis (the zero flow pressure or Pzf) and slope index of the pressure–flow relationship (SIPF) were calculated from the simultaneously recorded hyperaemic intracoronary blood flow velocity and aortic pressure after successful coronary stenting. Results: A stepwise increase in Pzf from AP (14.6 (8.0) mm Hg), over non-Q-wave MI (22.5 (9.1) mm Hg), to Q-wave MI (37.1 (12.9) mm Hg; p<0.001) was observed. Similar changes in Pzf were found in a reference artery perfusing the non-infarcted myocardium. Multivariate analysis showed that in both regions the left ventricular end-diastolic pressure (LVEDP) was the most important determinant of the Pzf. The SIPF was not statistically different in the treated vessel between patients with MI and AP, but was increased in MI patients with a markedly increased LVEDP. Conclusions: After an MI, the coronary pressure–flow relationship is shifted to the right both in the infarcted and in the non-infarcted remote myocardium, as shown by the increased Pzf. The correlation with Pzf suggests that elevated left ventricular filling pressures contribute to the impediment of myocardial perfusion in patients with infarction.

Hypersensitivity to Nadroparin Calcium

The use of heparin to prevent or treat venous and ethyl abuse, which was stopped 20 years before pulmonary thrombosis, unstable angina and admission. In order to perform right and left side non-ST-elevation myocardial infarction is widely cardiac catheterisation, oral anticoagulants were accepted. Nowadays, for many of these indications switched to nadroparin calcium (Fraxiparine®, Sathe unfractionated heparins (UFH; molecular weight nofi-Synthelabo, Brussels, Belgium)1 7.500U AXa [MW] 3–30 kDa) are largely being replaced by IC (Institut Choay) twice daily. Ten days after startlow-molecular-weight heparins (LMWHs; MW ≤5 ing this preservative-free LMWH he developed a kDa) because of the improved pharmacokinetic and large eczematous plaque (5 × 15cm) at the injection pharmacodynamic properties as well as a better site. There was neither thrombocytopenia nor eosisafety profile of the latter.[1-3] Adverse reactions to nophilia. The lesion subsided within 1 week after heparins include haemorrhages, osteopenia and imstopping the drug and application of a topical cortimune-mediated hypersensitivity reactions, e.g. costeroid. heparin-induced thrombocytopenia without and Investigations were performed in the patient and with (fatal) thrombosis,[4-10] immediate hypersensiin a healthy control who was free of any medication. tivity reactions such as rhinoconjunctivitis,[11] asthA lymphocyte transformation test (LTT) with ma,[12] urticaria, angio-oedema and anaphylaxnadroparin calcium assessed by the incorporation is,[12-25] and delayed cutaneous reactions generally of [methyl-3H] thymidine[36] was strongly positive manifesting as infiltrated, eczematous plaques or with a stimulation index, i.e. counts per minute leukocytoclastic vasculitis (type III Arthus reaction) (cpm) of the nadroparin calcium-stimulated lymat injection sites.[26-35] phocytes divided by the cpm cultured with serumfree medium, of 135 (normal <2). Flow cytometric 1. Case Report analysis of in vitro nadroparin calcium-activated A 47-year-old man with severe heart failure due basophils (BAT)[37] showed a CD63 upregulation to a dilated cardiomyopathy was admitted for carabove spontaneous expression of 63% (normal diac transplantation screening. His medical history <15%). Meanwhile, the patient was re-administered included pacemaker implantation because of a sick nadroparin calcium accidentally, which resulted in sinus syndrome with syncope, depression, osteoan immediate local erythematous eruption of several penia, gastritis, antral ulcers, a small biliary cyst and centimetres and a generalised pruritus and urticaria.

Impaired coronary flow reserve after a recent myocardial infarction: Correlation with infarct size and extent of microvascular obstruction

BACKGROUND The exact relationship between the coronary flow reserve (CFR) and infarct size remains unknown. In this prospective study the relationship between the CFR both in the infarcted and remote myocardium and infarct size was investigated. Furthermore, the diagnostic value of the CFR to predict the extent of microvascular obstruction (MO) was evaluated. METHODS In thirty patients the CFR was measured with a Doppler guide wire 6 ± 3 days after a first myocardial infarction (MI) in the infarct related and in a reference coronary artery. MO and infarct size were determined with magnetic resonance imaging. RESULTS The CFR was inversely related to infarct size in the infarcted and remote myocardium (respectively, r=-0.60, p<0.01 and r=-0.62, p<0.01). In the infarcted myocardium the extent of MO was strongly related to the infarct size and was in a multivariate analysis the single significant determinant of the CFR and the hyperaemic flow. In the remote myocardium no relationship was present between infarct size and hyperaemic flow, but the baseline flow increased as the infarct size became larger (r=0.58, p<0.01). In a receiver operator characteristic (ROC) analysis, a CFR value ≤ 2 in the infarct related coronary artery offered the best sensitivity (65%) and specificity (71%) to detect the presence of MO (p<0.05). CONCLUSIONS After MI, the CFR both in the infarcted and remote myocardium is inversely related to infarct size. In the infarcted myocardium, a CFR value ≤ 2 predicts the presence of MO with moderate sensitivity and specificity.

Adiponectin and ischemia-reperfusion injury in ST segment elevation myocardial infarction

Background: Models of experimental ischemia-reperfusion (IR) in adiponectin knockout animals have shown that adiponectin mediates protection against the development of IR injury. However, the role of adiponectin in IR injury in humans is largely unknown. Methods: In a total of 234 ST segment elevation myocardial infarction (STEMI) patients, baseline circulating total adiponectin concentration was correlated with IR injury after primary percutaneous coronary intervention (pPCI) and with major adverse cardiac events (MACE, death and cardiac hospitalization) during one year of follow up. IR injury was defined by serial electrocardiography (ECG) as >30% persistent ST segment elevation despite successful restoration of vessel patency and by angiography as thrombolysis in myocardial infarction (TIMI) blush grade<2. Results: IR injury was present in 31% of patients according to ECG criteria and in 28% of patients according to angiographic criteria. The median adiponectin level was 6.8 µg/ml in patients with ECG signs of IR injury and 6.5 µg/ml in patients without ECG signs of IR (p=0.26). When the angiographic criteria of IR were used, the median adiponectin level was 6.9 µg/ml for patients with IR versus 6.3 µg/ml for patients without IR (p=0.06). MACE occurred in 27% of the patients. Median adiponectin levels were similar in patients with MACE and in those without MACE: 6.3 vs. 6.4 µg/ml (p=0.24). In a multivariate model, no significant relation between circulating adiponectin levels and IR injury or MACE was evident. Conclusion: In the current era of pPCI, IR injury still occurs in almost one third of STEMI patients. Our findings do not support a major protective role of adiponectin in the prevention or attenuation of IR injury in these patients.

Resolute and Xience V polymer-based drug-eluting stents compared in an atherosclerotic rabbit double injury model.

To evaluate differences in strut coverage, inflammation and endothelialization between two second‐generation polymer‐based drug‐eluting stents (DES) in an atherosclerotic rabbit double‐injury iliac artery model at 28 days follow‐up. Methods and results: Rabbits with induced atheroma received bilateral iliac artery stents: everolimus‐eluting stent (Xience V EES; Abbott Vascular), zotarolimus‐eluting stent (Resolute ZES; Medtronic CardioVascular), or bare‐metal stent (BMS; MultiLink Vision; Abbott Vascular). After 28 days, total neointimal coverage examined by scanning electron microscopy was >98% for all three stent types. Neointimal thickness above stent struts was decreased by 50% in Xience V EES (0.06 ± 0.01 mm; P = 0.00001) compared with BMS (0.15 ± 0.03 mm) and Resolute ZES (0.12 ± 0.04 mm). Luminal area was largest for Xience V EES (3.79 ± 0.33 mm2; P = 0.0003 for Xience V EES vs. BMS), followed by Resolute ZES (3.46 ± 0.45 mm2; P = 0.083 for Resolute ZES vs. BMS) and BMS (3.07 ± 0.53 mm2). Percentage area stenosis was smallest for Xience V EES (17.23 ± 3.64%; P = 0.00001), while BMS (30.25 ± 7.48%) and Resolute ZES (30.79 ± 7.15%) did not differ. Endothelial monolayer regrowth was significantly lower in Resolute ZES (65 ± 13%) versus BMS (79 ± 11%; P = 0.004). There was no difference between Xience V EES (74 ± 10%) and BMS. Xience V EES was further associated with a lower number of inflammatory cells surrounding the stent struts (7 ± 2 per strut) in comparison to Resolute ZES (15 ± 6; P = 0.0001) and BMS (17 ± 9; P = 0.0005).

Clinical relevance of clopidogrel unresponsiveness during elective coronary stenting: Experience with the point-of-care Platelet Function Assay–100 C/ADP

BACKGROUND Early identification of nonresponders to clopidogrel may be important in identifying subgroups of patients that might be at risk for future thrombotic events. METHODS We prospectively assessed postclopidogrel platelet reactivity in 250 consecutive patients scheduled for elective percutaneous coronary intervention (PCI). All patients received dual antiplatelet therapy with 160 mg aspirin and a 300 mg loading dose of clopidogrel >12 hours before PCI. A platelet aggregation test was performed at the time of the intervention using a point-of-care assay, the Platelet Function Assay (PFA-100C/ADP; Dade-Behring, Deerfield, IL). Nonresponders were defined as having a PFA closure time of <71 seconds under dual oral antiplatelet therapy, reflecting normal platelet reactivity. Myonecrosis post-PCI constituted the primary end point and was defined as the release of creatine kinase-MB >1x the upper limit of normal on a sample taken 12 to 24 hours after intervention. The secondary end point was a composite end point of major adverse cardiac events including death, myocardial infarction, and stent thrombosis after 6 months. RESULTS The PFA closure time was available in 242 patients and ranged from 31 to 300 seconds with a mean value of 147 seconds. Nonresponders represented 7% (17/242) of the cases. Myonecrosis post-PCI occurred in 29 patients (12%) and was more common in nonresponders than in normal responders (29% vs 11%, respectively; P = .03 on multivariate analysis). Major adverse cardiac events at 6 months occurred in 13 patients (1 sudden death possibly related to stent thrombosis and 12 post-PCI myocardial infarctions) and were more common in the nonresponder group (12% vs 5%, respectively; P = .06 on multivariate analysis). CONCLUSIONS Unresponsiveness to clopidogrel as assessed by the point-of-care test PFA-100C/ADP is an independent major risk factor for thrombotic complications after coronary intervention.

Coronary artery-pulmonary artery fistula in a heart-transplanted patient.

A 64-year-old-man underwent routine elective right-left heart catheterization, 1 year after cardiac transplantation for terminal ischaemic cardiomyopathy. Surprisingly, selective coronary angiography disclosed coronary-pulmonary artery fistula with three feeding vessels originating from the proximal right coronary artery, the proximal portion of the left anterior descending artery, the circumflexus artery, and the left main coronary artery, draining into the pulmonary trunk. For this particular patient, without any significant cardiac complaints or symptoms, with normal cardiac dimensions and haemodynamic findings, a conservative approach was decided on.