Role of circulating endothelial progenitor cells in the reparative mechanisms of stable ischemic myocardium.

BACKGROUND: Mobilization of endothelial progenitor cells (EPCs) into circulation from bone marrow in patients with acute myocardial infarction has strong scientific evidence; less is known about EPC mobilization in patients with stable coronary artery disease (CAD). The aim of this study was to investigate the association of stable ischemic heart disease with EPC levels in tissue and blood. METHODS: Fifty-five consecutive patients admitted to a single treatment center for valve or coronary artery bypass grafting (CABG) surgeries were included in the study. Blood samples were collected in the morning before surgery and analyzed by flow-cytometry to determine peripheral EPC levels (EPC/ml). Tissue EPC (CD34+VEGFR2+) levels were assessed on a right atrial appendage segment. RESULTS: Mean age was 76±5years, 48% were men, and 53% had CAD The number of CD34+ VEGFR2+ cells in the tissue of patients with CAD was significantly higher (p<0.005) and circulating EPC showed a tendency to be reduced by approximately 20% in peripheral blood of patients with CAD when compared to those without CAD. CONCLUSION: Patients with stable CAD had higher EPC density values (EPC/mm2) and were more likely to have lower EPC blood levels when compare with normal controls.

Frequency and clinical correlates of bipolar features in acute coronary syndrome patients.

BACKGROUND: Depression and acute coronary syndrome (ACS) are both extremely prevalent diseases. Studies aimed at evaluating whether depression is an independent risk factor for cardiac events provided no definitive results. In most of these studies, depression has been broadly defined with no differentiation between unipolar (MDD) versus bipolar forms (BD). The aim of this study was to evaluate the frequency of DSM-IV BD (bipolar I and bipolar II subtypes, cyclothymia), as well as temperamental or isolated bipolar features in a sample of 171 patients hospitalized for ACS. We also explored whether these psychopathological conditions were associated with some clinical characteristics of ACS. METHODS: Patients with ACS admitted to three neighboring Cardiac Intensive Care Units (CICUs) in a 12-month continuative period of time were eligible for inclusion if they met the criteria for either acute myocardial infarct with or without ST-segment elevation or unstable angina, verified by standard ACS criteria. All patients underwent standardized cardiological and psychopathological evaluations. RESULTS: Of the 171 ACS patients enrolled, 37 patients (21.7%) were found to have a DSM-IV mood disorder. Of these, 20 (11.7%) had bipolar type I or type II or cyclothymia, while 17 (10%) were the cases of MDD. Rapid mood switches ranged from 11% of ACS patients with no mood disorders, to 47% of those with MDD to 55% of those with BD. Linear regression analysis showed that a diagnosis of BD (p=.023), but not that of MDD (p=.721), was associated with a significant younger age at the index episode of ACS. A history of previous coronary events was more frequent in ACS patients with BD than in those with MDD. CONCLUSIONS: Our data indicate that bipolar features and diagnosis are frequent in ACS patients. Bipolar disorder has a negative impact on cardiac symptomatology. Further research in this area is warranted.

Fibrin acts as biomimetic niche inducing both differentiation and stem cell marker expression of early human endothelial progenitor cells.

OBJECTIVES: Transplantation of endothelial progenitor cells (EPCs) is a promising approach for revascularization of tissue. We have used a natural and biocompatible biopolymer, fibrin, to induce cell population growth, differentiation and functional activity of EPCs. MATERIALS AND METHODS: Peripheral blood mononuclear cells were cultured for 1 week to obtain early EPCs. Fibrin was characterized for stiffness and capability to sustain cell population expansion at different fibrinogen-thrombin ratios. Viability, differentiation and angiogenic properties of EPCs were evaluated and compared to those of EPCs grown on fibronectin. RESULTS: Fibrin had a nanometric fibrous structure forming a porous network. Fibrinogen concentration significantly influenced fibrin stiffness and cell growth: 9 mg/ml fibrinogen and 25 U/ml thrombin was the best ratio for enhanced cell viability. Moreover, cell viability was significantly higher on fibrin compared to being on fibronectin. Even though no significant difference was observed in expression of endothelial markers, culture on fibrin elicited marked induction of stem cell markers OCT 3/4 and NANOG. In vitro angiogenesis assay on Matrigel showed that EPCs grown on fibrin retain angiogenetic capability as EPCs grown on fibronectin, but significantly better release of cytokines involved in cell recruitment was produced by EPC grown on fibrin. CONCLUSION: Fibrin is a suitable matrix for EPC growth, differentiation and angiogenesis capability, suggesting that fibrin gel may be very useful for regenerative medicine.

Role of endothelial progenitor cell mobilization after percutaneous angioplasty procedure.

Circulating endothelial progenitor cells (EPCs) are bone marrow-derived cells, contributing to endothelial cell regeneration of injured vessels as well as neovascularization of ischemic lesions. EPC levels and function are inversely correlated with cardiovascular risk factors, can predict the occurrence of adverse events and atherosclerotic disease progression. Ischemia and inflammation are the primary triggers for EPC mobilization and homing, however, vascular trauma, as it occurs during surgical procedures, has been demonstrated to stimulate EPC mobilization even in absence of tissue ischemia. The effect of angioplasty on EPCs is not well defined, mainly because of the different and sometimes contrasting clinical results, due to low numbers of patients enrolled and to lack of standardization in evaluating EPCs. Aim of this review is to report recent results on the effect of EPC mobilization and homing after angioplasty, attempting to summarize them in a comprehensive model. The effect on EPCs of different kind of stents and the potential use of new stents able to attract EPCs will be also described. Results obtained in patients undergoing angioplasty in different vascular districts (coronary, peripheral and carotid) will be shown, together with the correlation between circulating progenitor cells and restenosis.

Smoking and cardiovascular system: cellular features of the damage.

Two morphological features may be seen as a main result of the cardiovascular cell damage caused by cigarette smoking: myocardial cell necrosis and smoke cardiomyopathy that, however, can lead to cell necrosis in case of chronic prolonged exposure to tobacco smoke. Both these pathological patterns recognise hypoxia as the basic mechanism. Cardiovascular cell damage may involve either myocardial cell or coronary artery wall determining a varied but a wide spectrum of alterations. Necrosis may be well defined as a result of those morphological changes which follow cell death in a living tissue or organ with partial or total loss in their function. All infarcts of the heart muscle belong to the group of necrotic lesions, but not all cardiac necroses are necessarily infarcts. Coronarogenic, or non-coronarogenic mechanism following a direct action of tobacco compounds on myocardial cells may induce myocardial cell necrosis. Smoke cardiomyopathy is probably the most typical evidence of cellular damage induced by cigarette smoking on the myocardium. The term cardiomyopathy is used to describe all those forms of degenerative myocardial lesions caused directly by toxics or metabolic substances and, indirectly, by changes in blood flow which are able to induce chronic hypoxia. Initially, smoke cardiomyopathy is not characterised by necrotic phenomena but, instead, by alterations of those intracellular structures RNA- related like mitochondria and ribosomes, which are primarily deputed to carry out metabolic and respiratory pathways of myocardial cells, the function of which strongly depends on oxygen availability. Experimental findings documented undoubtedly either the type of cellular changes or their reproducibility after both acute or chronic exposure to cigarette smoke.

Circulating endothelial progenitor cells characterization, function and relationship with cardiovascular risk factors.

Since the first description of putative progenitor endothelial cells mobilized from bone marrow by stimuli like ischemia and cytokines, several studies in animals have confirmed their role in neovascularization of ischemic organs. In ischemic myocardium endothelial progenitor cells can prevent cardiomyocyte apoptosis, reduce remodeling and improve cardiac function. These observations led to the hypothesis of endothelial progenitor cells as possible cell-based therapy in patients by autologous transplantation in ischemic tissue or by improving peripheral circulating numbers with mobilization by cytokines. Early trials, including a randomized one, suggest that the intracoronary autologous bone marrow cell transfer after myocardial infarction exerts at least short term functional benefits. Since endothelial damage and dysfunction play a critical role in atherosclerosis disease, research interest was addressed to evaluate the role of progenitor endothelial cells in vascular endothelial layer maintenance. Opposing to local resident endothelial cells poor proliferation rate, progenitor endothelial cells regenerative capacity, homing and integration into blood vessels have been interpreted as a protective role of these cells in vascular homeostasis. Indeed, the number and function of endothelial progenitor cells relate with the progression of atherosclerosis; the accumulation of cardiovascular risk factors or an increased overall risk are inversely associated with endothelial progenitor cells number and function. Finally, recent studies have shown a role of progenitor cells numbers to predict cardiovascular events, raising endothelial progenitor cells to the podium of novel prognostic biomarker.

Glucose tolerance is negatively associated with circulating progenitor cell levels.

AIMS/HYPOTHESIS: Circulating progenitor cells participate in cardiovascular homeostasis. Depletion of the pool of endothelial progenitor cells (EPCs) is associated with increased cardiovascular risk. Furthermore, EPCs are reduced in the presence of classical risk factors for atherosclerotic disease, including diabetes mellitus. This study was designed to evaluate progenitor cell levels in volunteers with different degrees of glucose tolerance. METHODS: Cardiovascular parameters and the levels of circulating CD34(+) and CD34(+) kinase insert domain receptor (KDR)(+) cells were determined in 219 middle-aged individuals with no pre-diagnosed alterations in carbohydrate metabolism. Glucose tolerance was determined by fasting and 2 h post-challenge glucose levels, with IFG and IGT considered as pre-diabetic states. RESULTS: CD34(+) and CD34(+)KDR(+) cells were significantly reduced in individuals who were found to have diabetes mellitus, and were negatively correlated with both fasting and post-challenge glucose in the whole population. While only CD34(+) cells, but not CD34(+)KDR(+) cells, were significantly reduced in pre-diabetic individuals, post-challenge glucose was an independent determinant of the levels of both CD34(+) and CD34(+)KDR(+) cells. CONCLUSIONS/INTERPRETATION: Glucose tolerance was negatively associated with progenitor cell levels in middle-aged healthy individuals. Depletion of endothelial progenitors with increasing fasting and post-meal glucose may be one cause of the high incidence of cardiovascular damage in individuals with pre-diabetes.

The effects of acute passive smoke exposure on endothelium-dependent brachial artery dilation in healthy individuals.

Passive smoking has both short-term and long-term vascular effects. It is not clear whether impairment of endothelial function reflects the acute effects of passive smoke exposure or the chronic effects. The purpose of this study was to assess the hypothesis that short-term exposure to passive smoke impairs endothelium-dependent vasodilation in healthy nonsmokers. Eighteen healthy young never smokers (12 men, 6 women) 21 to 55 years old (mean +/- SD: 34 +/-9 years) underwent ultrasonography measuring baseline brachial-artery diameter and brachial-artery diameter during hyperemia and after sublingual administration of nitroglycerin, twice: in a smoke-free environment, and then in the same environment polluted by 30 to 35 ppm carbon monoxide. Each subject served as his/her control. Carboxyhemoglobin was measured in blood samples of subjects tested. Mean value of carboxyhemoglobin was 0.6 +/-0.5% in a smoke-free environment and 1.4 +/- 0.5% in a smoking environment (p <0.02). Mean values of flow-mediated dilation (FMD) were 12.6% +/- 7.8% in a smoke-free environment versus 6.8 +/- 7.8% in a smoking environment (p <0.01). On the contrary, nitroglycerin-induced vasodilation did not show any statistical difference (21 +/- 9.8% versus 23 +/-1.4%). Finally, the increase of carboxyhemoglobin was related statistically to the impairment of flow-mediated dilation (r = 0.51; p <0.002). Passive smoking impaired flow-mediated vasodilation in healthy never smokers in a smoking environment. The impairment was strongly related to carboxyhemoglobin level.

Is transcutaneous oxygen and carbon dioxide monitoring indispensable in short- and long-term therapeutic management of non-reconstructable lower critical limb ischemia?

AIM: The aim of this study was to evaluate the capacity of transcutaneous partial pressure of O(2) (TCpO(2)) and CO(2) (TCpCO(2)) to predict clinical response to pharmacological treatment in short- and long-term follow-up of unreconstructable critical limb ischemia (CLI) treated with prostanoids; to suggest a diagnostic and therapeutic algorithm able to define the possibility of prostanoid therapy in unreconstructable CLI at high risk of limb loss. METHODS: Twenty-six consecutive patients with CLI (21 with distal trophic lesions, 31 symptomatic limbs) considered unreconstructable after peripheral angiography and with a history of type 2 diabetes mellitus underwent daily parenteral Iloprost treatment for 2-3 weeks. RESULTS: Transcutaneous gas-analytic monitoring (TGM) in non-reconstructable CLI treated with Iloprost divided patients into 2 groups: early responders (ER) with increased TcpO(2) and normalization of TcpCO2, and non responders (NR) with unchanged TcpO(2) and TcpCO(2) parameters. In the NR who underwent a second cycle of Iloprost within a few months of the first, TGM further divided the patients into another subgroup of late responders (LR) with TcpO(2) and TcpCO(2) similar to the ER group and a subgroup of NR, who, after pharmacological treatment failure, should undergo eventual surgical re-timing and/or spinal cord stimulation in a final attempt to save the limb. CONCLUSIONS: In the short-term follow-up of CLI, a marked reduction in supine/dependent TcpO(2) and a marked increase in supine TcpCO(2) at the symptomatic forefoot proved to be significant predictors of major amputation risk. In the long-term follow-up period, TGM showed that, in ER and in LR, the favourable effect of pharmacological therapy observed in the first 6 months will disappear over the next 6 months, suggesting an algorithm of 2- to 3-week cycles of prostanoid therapy repeated every year. In NR treated with surgical and/or alternative therapies who did not undergo major amputations, prolonged instrumental TGM will provide a constant evaluation of metabolic parameters, thus providing the possibility to save the limb with additional pharmacological therapy.

An in vitro study on the free radical scavenging capacity of ergothioneine: comparison with reduced glutathione, uric acid and trolox.

BACKGROUND: Treatment of oxidative stress-related pathologies is a possible therapeutical strategy for the future. Natural product with antioxidant properties could trigger this goal. The aim of this in vitro study was to assess the antioxidant activity of the natural product ergothioneine (EGT), a compound of plant origin, which is assimilated and conserved by mammals in erythrocytes, kidney, seminal fluid and liver. METHODS: We measured the antioxidant activity of EGT as its ability to antagonize the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) by hydroxyl radical, peroxyl radicals and peroxynitrite. The results are expressed as total oxyradical scavenging capacity (TOSC) units. Glutathione (GSH), uric acid and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), the water-soluble analog of vitamin E, were used as the reference antioxidants. RESULTS: EGT was the most active scavenger of free radicals as compared to classic antioxidants as GSH, uric acid and trolox. In particular, the highest antioxidant capacity exhibited by EGT vs. peroxyl radicals (5.53 +/- 1.27 units) resulted 25% higher than the value obtained with the reference antioxidant trolox (4.4 +/- 0.6 units, P < 0.01). The scavenging capacity of EGT towards hydroxyl radicals (0.34 +/- 0.09 units) was 60% higher, as compared to uric acid (0.21 +/- 0.04 units, P < 0.001), which represent the reference antioxidant vs. hydroxyl radicals. Finally, EGT showed the highest antioxidant activity also towards peroxynitrite (5.2 +/- 1.0 units), with a scavenging capacity 10% higher than that of uric acid (4.7 +/- 0.9 units, P < 0.05). CONCLUSIONS: This study showed that EGT has potent intrinsic anti-hydroxyl, anti-peroxyl and anti-peroxynitrite radicals antioxidant activity, as compared to classic molecules with antioxidant capacity as GSH, trolox and uric acid. This appears of interest, given the increasing use of non-vitamins cocktails for therapeutical approaches to many oxidative-induced pathologies.

Myocardial systolic strain abnormalities in patients with acromegaly: a prospective color Doppler imaging study.

BACKGROUND: Heart abnormalities are frequent findings in patients with acromegaly: systolic abnormalities are considered to be secondary to diastolic changes. AIM: The aim of the study was to evaluate whether early systolic abnormalities might be revealed in acromegalic patients using the high sensitive color Doppler myocardial imaging (CDMI) technique. PATIENTS AND METHODS: Twenty-two consecutive acromegalic patients with active untreated disease (ACROUNTR) were evaluated at baseline and after a 6-month course with SS analogs (SSa) (ACROSSa); 25 healthy subjects served as controls. All subjects underwent conventional 2D-color Doppler echocardiography, pulse wave tissue Doppler imaging (PW-TDI) and CDMI. RESULTS: Mean left ventricular (LV) ejection fraction did not differ in ACROUNTR and in controls; at variance, ACROUNTR patients had reduced mean LV diastolic function (E/A ratio: 0.96+/-0.3 vs controls: 1.6+/-0.3; p<0.002). Impairment of global LV diastolic function was confirmed by PW-TDI in ACROUNTR patients having a normal systolic function. Regional myocardial systolic strain (epsilon) and strain rate (SR) values, indices of regional systolic heart deformation, were lower in ACROUNTR [epsilonsys (S) -19.8+/-2.9 and epsilonsys (L): -17.7+/-2.2] than in controls [epsilonsys (S): -27.9+/-3.8; p<0.001 and epsilonsys (L): -25.3+/-2.6; p<0.001]. In addition, the early phase of diastolic function, evaluated using SR parameters, was impaired in acromegalic patients (p<0.005 vs controls). Strain and SR values were related to serum GH and IGF-I levels (p<0.02) and greatly improved after a 6-month course with SSa [epsilonsys (S) improved to -23.8+/-3.8 (p<0.05) and epsilonsys (L) improved to -24.7+/-2.4 (p<0.03)]. CONCLUSIONS: Our study confirms that ACROUNTR patients have impaired diastolic function. More important, our study clearly shows that ACROUNTR patients have an impairment of regional myocardial systolic function, which is not secondary to diastolic changes. These intramyocardial functional abnormalities improved during medical treatment of acromegaly. It is conceivable that GH-IGF-I excess has detrimental effects either on the diastolic or the systolic phases of heart function.

Relationship between preclinical abnormalities of global and regional left ventricular function and insulin resistance in severe obesity: a Color Doppler Imaging Study.

BACKGROUND: The aim of this study was to evaluate the relationship between insulin resistance and preclinical abnormalities of the left ventricular structure and function detected in severe obesity by Color Doppler Myocardial Imaging (CDMI). Forty-eight consecutive severely obese patients (Group O) (11 males, 37 females, mean age 32.8+/-7 years) were enrolled. Forty-eight sex- and age-matched non-obese healthy subjects were also recruited as controls (Group C). All subjects underwent conventional 2D-Color Doppler echocardiography and CDMI. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance results. Obese subjects had a greater left ventricular mass index (by height) (58.8+/-14 g/m(2.7)) than controls (37+/-8 g/m(2.7)) (P<0.0001), owing to compensation response to volume overload caused by a greater cardiac output (P<0.02). Preload reserve was increased in obese subjects, as demonstrated by a significant increase in left atrial dimension (P<0.0001). Obese patients had a slightly reduced LV diastolic function (transmitral E/A ratio: Group O, 1.1+/-0.8 vs Group C, 1.5 +/-0.5; P<0.002). Cardiac deformation assessed by regional myocardial systolic strain and strain rate (SR) values was significantly lower (abnormal) in obese patients than in controls, both at the septum and lateral wall level. These strain and SR abnormalities were significantly related to body mass index. In addition, the early phase of diastolic function, evaluated using SR, was compromised in obese patients (P<0.001). The HOMA-IR values in obese patients were significantly higher (3.09+/-1.6) than those determined in the control group (0.92+/-0.5) (P<0.0001). The HOMA-IR values, in the obese group, were significantly related to systolic strain and SR values sampled at the septum level (P<0.0001). CONCLUSION: In conclusion, this study has demonstrated that obese patients pointed out systolic structural and functional abnormalities at a preclinical stage, in particular through strain and SR analysis; on the other hand, those altered CDMI parameters well distinguish obese subjects as compared with the control group. Furthermore, another main finding of the study was that myocardial deformation (systolic strain) could have a correlation with insulin resistance level.

Thrombolytic therapy in peripheral arterial disease.

The two main causes of peripheral arterial occlusion (PAO) are embolism and thrombosis. Surgical treatment of acute limb ischemia, because of related complications, has a 30-day mortality rate of 15% to 25%. Intra-arterial thrombolysis for lower extremity ischemia is a well-accepted and frequently used technique. It may offer definitive treatment without the need for major surgery in a significant series of patients with acute occlusion of a native leg artery or a by-pass graft. Thrombolysis can offer several potential advantages when compared with surgical therapy. Thrombolytic agents include streptokinase (SK), urokinase (UK), pro-UK and recombinant tissue plasminogen activators (rt-PA-Alteplase and r-PA-Reteplase). All these agents induce a systemic fibrinolytic state. Three prospective randomized trials, ROCHESTER, STILE, and TOPAS, which compared thrombolytic therapy with traditional surgical revascularization for lower limb ischemia, have recently been published. They suggest that thrombolysis, as an initial therapy, reduces the risk of subsequent surgery and improves limb salvage for patients with PAO. Using this approach, the underlying lesions can be identified and treated by transluminal balloon angioplasty or stenting, or by elective surgical revascularization. However, severe bleeding is still a non rare complication of intra-arterial thrombolysis and the risk of intracranial hemorrhage is 1-2%.

Dissociation between microalbuminuria and common carotid thickness in essential hypertensive men.

BACKGROUND: The reasons why microalbuminuria (albuminuria > or = 15 microg/min), an expression of a renal microcirculatory abnormality, predicts cardiovascular disease in essential hypertension are unsettled. To test the hypothesis that microalbuminuria represents a marker of subclinical atherosclerosis, we evaluated its association with common carotid artery (CCA) intima media thickness (IMT), a measure of preclinical atherosclerosis and an independent predictor of cardiac and cerebrovascular events, in uncomplicated essential hypertensive individuals. MATERIALS AND METHODS: Albuminuria, ultrasonographic CCA IMT (the mean of six bilateral far wall measurements within 1.5 cm proximally to the flow divider), brachial blood pressure (BP), smoking habits and lipids were evaluated in 136 stage 1-3 untreated essential hypertensive men free of cardiovascular disease. RESULTS: CCA IMT did not differ between normo- (n = 99) and microalbuminuric (n = 37) patients. The correlation between CCA IMT and albuminuria was not significant, and the prevalence of microalbuminuria across IMT quartiles was not different. Microalbuminuric patients showed higher systolic BP and that parameter was the only independent correlate in a multivariate logistic regression model including also age, CCA IMT, diastolic BP, lipids and smoking habits as independent variables and microalbuminuria as the dependent one. CONCLUSION: This cross-sectional study in hypertensive subjects free of cardiovascular disease has shown a dissociation between microalbuminuria and CCA IMT, a surrogate measure of subclinical atherosclerosis, and a parameter linearly related to cardiovascular events. The data do not support the theory of microalbuminuria as a surrogate measure of subclinical atherosclerosis, while confirming the importance of systolic BP levels as an independent correlate of increased albuminuria in essential hypertension. Journal of Human Hypertension (2000) 14, 831-835

Usefulness of carotid intima-media thickness measurement and peripheral B-mode ultrasound scan in the clinical screening of patients with coronary artery disease.

Previous observational studies have shown a relationship between carotid intima-media thickness (IMT) and coronary artery disease (CAD). In this study the authors evaluated the accuracy of the common carotid IMT measurement in predicting the presence and severity of CAD and the additional information offered by the detection of carotid, iliac, and lower limb plaques. One hundred and fifty consecutive patients were subjected to coronary angiography and carotid, iliac, and lower limb ultrasound scan. The mean value of six IMT measurements of the far wall of the common carotid artery was calculated in each patient. The mean IMT was significantly correlated to the number of stenosed coronary vessels (r = 0.43, p<0.001), although the positive and negative predictive value of mean IMT in identifying patients with CAD was low (81% and 46%, respectively). The combined information offered by IMT measurements and peripheral (carotid, iliac, and lower limb) plaque detection was then used to obtain the best multivariate regression model able to predict CAD status. The multivariate model showed a highly significant multiple correlation coefficient (r = 0.60, p<0.0001) and a sharp improvement in the negative predictive value (92%) with respect to the univariable model. B-mode ultrasound scan including common carotid IMT measurement and peripheral plaque detection may be of clinical value in the screening of patients with CAD.