Franca S. Angeli

Brief secondhand smoke exposure depresses endothelial progenitor cells activity and endothelial function: sustained vascular injury and blunted nitric oxide production.

OBJECTIVES This study sought to analyze the effects of acute secondhand smoke (SHS) exposure on the number and function of endothelial progenitor cells (EPCs) over 24 h. BACKGROUND Secondhand smoke increases the risk of vascular disease and is a major public health concern, but the mechanism(s) of action are not fully understood. METHODS Healthy nonsmokers (age SEM 30.3 +/- 1.3 years, n = 10) were exposed to 30 min of SHS yielding cotinine levels commonly observed in passive smokers and to smokefree air on 2 separate days. Measurements were taken before exposure (baseline), immediately after (0 h), and at 1 h, 2.5 h, and 24 h after. The EPCs (CD133(+)/KDR(+), CD34(+)/KDR(+)) and endothelial microparticles (EMPs: CD31(+)/CD41(-), CD144(+), CD62e(+)) were determined in blood using flow cytometry. The EPC chemotaxis toward vascular endothelial growth factor was measured. Endothelial function was assessed as flow-mediated dilation (FMD) using ultrasound. RESULTS Secondhand smoke exposure increased EPCs and plasma vascular endothelial growth factor and completely abolished EPC chemotaxis during 24 h after exposure. Secondhand smoke increased EMPs and decreased FMD. Although FMD returned to baseline at 2.5 h, EMPs and vascular endothelial growth factor levels remained elevated at 24 h, suggesting endothelial activation and injury with functional impairment of the vascular endothelium. Exposure to smokefree air had no effect. Incubation of EPCs from nonexposed subjects with plasma isolated from SHS-exposed subjects in vitro decreased chemotaxis by blockade of vascular endothelial growth factor-stimulated nitric oxide production. CONCLUSIONS Brief exposure to real-world levels of SHS leads to sustained vascular injury characterized by mobilization of dysfunctional EPCs with blocked nitric oxide production. Our results suggest that SHS not only affects the vascular endothelium, but also the function of EPCs.

Improvement of Endothelial Function With Dietary Flavanols Is Associated With Mobilization of Circulating Angiogenic Cells in Patients With Coronary Artery Disease

OBJECTIVES In patients with coronary artery disease (CAD) medically managed according to currently accepted guidelines, we tested whether a 1-month dietary intervention with flavanol-containing cocoa leads to an improvement of endothelial dysfunction and whether this is associated with an enhanced number and function of circulating angiogenic cells (CACs). BACKGROUND Dietary flavanols can improve endothelial dysfunction. The CACs, also termed endothelial progenitor cells, are critical for vascular repair and maintenance of endothelial function. METHODS In a randomized, controlled, double-masked, cross-over trial, 16 CAD patients (64+/-3 years of age) received a dietary high-flavanol intervention (HiFI [375 mg]) and a macronutrient- and micronutrient-matched low-flavanol intervention (LoFI [9 mg]) twice daily in random order over 30 days. RESULTS Endothelium-dependent vasomotor function, as measured by flow-mediated vasodilation of the brachial artery, improved by 47% in the HiFI period compared with the LoFI period. After HiFI, the number of CD34+/KDR+-CACs, as measured by flow cytometry, increased 2.2-fold as compared with after LoFI. The CAC functions, as measured by the capacity to survive, differentiate, proliferate, and to migrate were not different between the groups. The HiFI led to a decrease in systolic blood pressure (mean change over LoFI: -4.2+/-2.7 mm Hg), and increase in plasma nitrite level (mean change over LoFI: 74+/-32 nM). Applying a mixed-effects linear regression model, the results demonstrated a significant increase in flow-mediated vasodilation and a decrease in systolic blood pressure with increasing levels of CD34+/KDR+-CACs. CONCLUSIONS Sustained improvements in endothelial dysfunction by regular dietary intake of flavanols are associated with mobilization of functional CACs. (Effect of Cocoa Flavanols on Vascular Function in Optimally Treated Coronary Artery Disease Patients: Interaction Between Endothelial Progenitor Cells, Reactivity of Micro- and Macrocirculation; NCT00553774).

Injection of bone marrow cell extract into infarcted hearts results in functional improvement comparable to intact cell therapy.

We compared therapeutic benefits of intramyocardial injection of unfractionated bone marrow cells (BMCs) versus BMC extract as treatments for myocardial infarction (MI), using closed-chest ultrasound-guided injection at a clinically relevant time post-MI. MI was induced in mice and the animals treated at day 3 with either: (i) BMCs from green fluorescent protein (GFP)-expressing mice (n = 14), (ii) BMC extract (n = 14), or (iii) saline control (n = 14). Six animals per group were used for histology at day 6 and the rest followed to day 28 for functional analysis. Ejection fraction was similarly improved in the BMC and extract groups versus control (40.6 +/- 3.4 and 39.1 +/- 2.9% versus 33.2 +/- 5.0%, P < 0.05) with smaller scar sizes. At day 6 but not day 28, both therapies led to significantly higher capillary area and number of arterioles versus control. At day 6, BMCs increased the number of cycling cardiomyocytes (CMs) versus control whereas extract therapy resulted in significant reduction in the number of apoptotic CMs at the border zone (BZ) versus control. Intracellular components within BMCs can enhance vascularity, reduce infarct size, improve cardiac function, and influence CM apoptosis and cycling early after therapy following MI. Intact cells are not necessary and death of implanted cells may be a major component of the benefit.

Increased CD62e+ Endothelial Microparticle Levels Predict Poor Outcome in Pulmonary Hypertension Patients

BACKGROUND Endothelial and leukocytes-derived microparticles (EMPs and LMPs, respectively) are increased in patients with pulmonary hypertension (PH). We hypothesized that the levels of circulating EMPs and LMPs could predict outcome in these patients. METHODS Patients undergoing right heart catheterization for untreated pre-capillary PH were eligible for the study. Baseline hemodynamics and biologic and clinical parameters were measured at the time of enrollment. Measurements of CD62e(+), CD144(+) and CD31(+)/CD41(-) EMPs and CD45(+) LMPs were performed using flow cytometry in venous platelet-free plasma samples. After inclusion, patients were treated at the discretion of the physician and prospectively followed for 12 months. The primary end-point was the combined occurrence of death and re-admission for right heart failure (RHF) or worsening of RHF symptoms. RESULTS Seven of 21 patients (mean age 54.1 +/- 3.5 years, 62% female) experienced the primary end-point during the study period. These patients had higher baseline levels of CD62e(+) EMPs, LMPs and hsCRP (high sensitivity C-reactive protein) compared to patients without events (p < 0.05), whereas no difference was observed for other microparticles and functional and hemodynamics parameters. Receiver operating curve analysis showed that baseline CD62e(+) EMPs levels of >353 events/microl predicted clinical complications. Kaplan-Meier analysis revealed that patients with baseline CD62e(+) EMPs above this cut-off value had a significantly worse prognosis compared with those subjects who had levels below this cut-off (p = 0.02, log-rank statistics). CONCLUSIONS Elevated levels of circulating CD62e(+) EMPs but not LMPs in PH patients prior to treatment are associated with adverse clinical events. Assessment of CD62e(+) EMPs levels may represent a new tool for stratification of PH patients.

Cardiomyopathy of aging in the mammalian heart is characterized by myocardial hypertrophy, fibrosis and a predisposition towards cardiomyocyte apoptosis and autophagy

Aging is associated with an increased incidence of heart failure, but the existence of an age-related cardiomyopathy remains controversial. Differences in strain, age and technique of measuring cardiac function differ between experiments, confounding the interpretation of these studies. Additionally, the structural and genetic profile at the onset of heart failure has not been extensively studied. We therefore performed serial echocardiography, which allows repeated assessment of left ventricular (LV) function, on a cohort of the same mice every 3 months as they aged and demonstrated that LV systolic dysfunction becomes apparent at 18 months of age. These aging animals had left ventricular hypertrophy and fibrosis, but did not have inducible ventricular tachyarrhythmias. Gene expression profiling of left ventricular tissue demonstrated 40 differentially expressed probesets and 36 differentially expressed gene ontology terms, largely related to inflammation and immunity. At this early stage of cardiac dysfunction, we observed increased cardiomyocyte expression of the pro-apoptotic activated caspase-3, but no actual increase in apoptosis. The aging hearts also have higher levels of anti-apoptotic and autophagic factors, which may have rendered protection from apoptosis. In conclusion, we describe the functional, structural and genetic changes in murine hearts as they first develop cardiomyopathy of aging.

Dietary flavanol intervention lowers the levels of endothelial microparticles in coronary artery disease patients

Current evidence suggests that regenerative v. degenerative endothelial responses can be integrated in a clinical endothelial phenotype, reflecting the net result between damage from risk factors and endogenous repair capacity. We have previously shown that a cocoa flavanol (CF) intervention can improve endothelial function and increase the regenerative capacity of the endothelium by mobilising circulating angiogenic cells in patients with coronary artery disease (CAD). The aim of the present study was to investigate whether CF can lower the levels of circulating endothelial microparticles (EMP), markers of endothelial integrity, along with improvements in endothelial function. The levels of EMP in the frozen plasma samples of CAD patients were measured along with endothelial function (flow-mediated vasodilation, FMD); n 16, FMD data published previously), and these data were compared with those of young (n 12) and age-matched (n 12) healthy control subjects. The CAD patients exhibited significantly increased levels of EMP along with impaired FMD when compared with the healthy control subjects. The levels of CD144⁺ and CD31⁺/41⁻ EMP were inversely correlated with FMD (r -0.67, P=0.01 and r -0.59, P=0.01, respectively). In these CAD patients, the levels of EMP were measured after they had consumed a drink containing 375 mg of CF (high-CF intervention, HiFI) or 9 mg of CF (macro- and micronutrient-matched low-CF control, LoFl) twice daily over a 30-d period in a randomised, double-blind, cross-over study. After 1 month of HiFI, the levels of CD31⁺/41⁻ and CD144⁺ EMP decreased (-25 and -23%, respectively), but not after LoFl. Our data show that flavanols lower the levels of EMP along with higher endothelial function, lending evidence to the novel concept that flavanols may improve endothelial integrity.

Cytokine Combination Therapy With Long-Acting Erythropoietin and Granulocyte Colony Stimulating Factor Improves Cardiac Function But is Not Superior Than Monotherapy in a Mouse Model of Acute Myocardial Infarction

BACKGROUND Erythropoietin (EPO) and granulocyte colony stimulating factor (GCSF) are potential novel therapies after myocardial infarction (MI). We first established the optimal and clinically applicable dosages of these drugs in mobilizing hematopoietic stem cells (HSC), and then tested the efficacy of monotherapy and combination therapy post-MI. METHODS AND RESULTS Optimal doses were established in enhanced green fluorescent protein (eGFP) + chimeric mice (n = 30). Next, mice underwent MI and randomized into 4 groups (n = 18/group): 1) GCSF; 2) EPO; 3) EPO+GCSF; and 4) control. Left ventricular (LV) function was analyzed pre-MI, at 4 hours and at 28 days post-MI. Histological assessment of infarct size, blood vessels, apoptotic cardiomyocytes, and engraftment of eGFP+ mobilized cells were analyzed at day 28. LV function in the control group continued to deteriorate, whereas all treatments showed stabilization. The treatment groups resulted in less scarring, increased numbers of mobilized cells to the infarct border zone (BZ), and a reduction in the number of apoptotic cardiomyocytes. Both EPO groups had significantly more capillaries and arterioles at the BZ. CONCLUSION We have established the optimal doses for EPO and GCSF in mobilizing HSC from the bone marrow and demonstrated that therapy with these agents, either as monotherapy or combination therapy, led to improvement of cardiac function post-MI. Combination therapy does not seem to have additive benefit over monotherapy in this model.

Granulocyte colony stimulating factor in myocardial infarction with low ejection fraction.

BACKGROUND We investigated the safety and efficacy of GCSF therapy in a porcine model of ischemia-reperfusion with left ventricle ejection fraction of <45% using a clinically relevant dosing and timing regimen. METHODS MI was induced in pigs by a 90 min balloon occlusion of the left anterior descending coronary artery. Sixteen animals were randomized to either GCSF (IV bolus of 10 microg/kg at time of reperfusion, followed by SC injections of 5 microg/kg days 5-9 post-MI) or saline (control group). Inflammatory markers, bone marrow cell mobilization and LV function (echocardiography and pressure-volume measurements) were assessed at baseline, 1 and 6 weeks post-MI. Histopathology was performed 6 weeks post-MI. RESULTS GCSF therapy was associated with a significant increase in white blood cell counts. At week 6, GCSF therapy resulted in less deterioration of LVEF compared to control (38+/-2% vs. 33+/-2%, p<0.02) and improved wall motion score index (p<0.05). Histopathology revealed increased vascular density (p<0.05) and a trend toward increased areas of viable myocardium compared to control (p=0.058). CONCLUSION GCSF therapy prevents further deterioration of LV function in a porcine model of MI with lower EF (<45%). These results support future clinical trials with GCSF in selected patients with larger MI.

Prolonged Therapy With Erythropoietin is Safe and Prevents Deterioration of Left Ventricular Systolic Function in a Porcine Model of Myocardial Infarction

BACKGROUND Erythropoietin (EPO) has generated interest as a novel therapy after myocardial infarction (MI), but the safety and efficacy of prolonged therapy have not been studied in a large animal model of reperfused MI. METHODS AND RESULTS MI was induced in pigs by a 90-minute balloon occlusion of the left anterior descending coronary artery. Sixteen animals were randomized to either EPO or saline (control group). Inflammatory markers, bone marrow cell mobilization, and left ventricular function (by both echocardiography and pressure-volume measurements) were assessed at baseline, 1 and 6 weeks post-MI. EPO therapy was associated with a significant increase in hemoglobin and mononuclear counts. D-dimer and C-reactive protein levels did not differ between groups. At week 6, EPO therapy prevented further deterioration of left ventricular ejection fraction (39 +/- 2% vs. 33 +/- 1%, P < .01) and improved wall motion score index (P < .02). Histopathology revealed increased areas of viable myocardium, vascular density, and capillary-to-myocyte ratio in the EPO therapy compared with the control (all P < .05). CONCLUSION Prolonged EPO therapy after MI in a large animal model is safe and leads to an increase in viable myocardium, increased vascular density, and prevents further deterioration of left ventricular function. These results support future clinical studies in post-MI patients.

Fractionation of mouse bone-marrow cells limits functional efficacy in non-reperfused mouse model of acute myocardial infarction.

Abstract Background and objectives. Clinical trials of bone-marrow (BM)-derived cells for therapy after acute myocardial infarct (MI) have been controversial. The most commonly used cells for these trials have been mononuclear cells (MNC), obtained by fractionation of BM cells (BMCs) via different protocols. In this study, we performed a head-to-head comparison of: 1) whole BMC; 2) fractionated BM (fBM) using the commonly used Ficoll protocol; 3) the extract derived from the fBM (fBM extract) versus 4) saline (HBSS) control for treatment of acute MI. Methods. In total, 155 male C57BL/6J (10–12-week old) mice were included. Echocardiography was performed at baseline and 2 days after permanent ligation of the left anterior descending artery to induce MI. Echocardiography and histology were employed to measure outcome at 28 days post-MI. Results. Whole BMC therapy improved left ventricular ejection fraction (LVEF) post-MI, but fBM or fBM extract was not beneficial compared to control (change of LVEF of 4.9% ±4.6% (P = 0.02), –0.4% ±5.8% (P = 0.86), –2.0% ±6.2% (P = 0.97) versus −1.4% ±5.3%, respectively). The histological infarct size or numbers of arterioles or capillaries at infarct or border zone did not differ between the groups. Conclusions. Clinical studies should be performed to test whether whole BMC therapy translates into better outcome also after human MI.