Biomedical subjects

Gad Keren

Publications and source records attributed to Gad Keren.

At least 37 records · Page 2Linked to original sources

PubMed2005

Erythropoietin promotes endothelial progenitor cell proliferative and adhesive properties in a PI 3-kinase-dependent manner.

OBJECTIVES: Patients with congestive heart failure (CHF) suffer considerable morbidity and mortality despite advances in therapy. Treatment with erythropoietin (Epo) has shown promise in CHF patients, yet its mechanisms of action remain elusive. Endothelial progenitor cells (EPC) contribute to postnatal angiogenesis and vasculogenesis, and Epo was shown to promote EPC mobilization. We explored the effect of chronic treatment with Epo on the numbers and functional properties of EPC in CHF patients. METHODS AND RESULTS: Twenty-eight patients with CHF treated with Epo for a mean period of 28 months were compared to a matched group (n = 28) with regard to the number of circulating hematopoietic and endothelial stem cells (either CD34+, CD34+/CD45+, CD34+/CD133+, CD34+/VEGF-R2+ or CD34+/CD133+/VEGF-R2+) as well as their proliferative and adhesive capacity. In vitro, Epo was added to cultured EPC from healthy subjects to test proliferation and adhesion. No differences were observed in circulating numbers of hematopoietic and endothelial stem cells between CHF patients chronically treated with Epo or untreated. EPC from Epo-treated patients exhibited enhanced proliferation as well as a trend towards adhesion to cultured endothelial cells prior to and following stimulation with TNF-alpha. Addition of Epo to EPC from healthy subjects dose-dependently increased their proliferation and adhesion to fibronectin, cultured endothelial cells, and cardiomyocytes. These effects were significantly reduced in the presence of phosphatidylinositol (PI) 3-kinase inhibitors. CONCLUSIONS: Chronic Epo treatment is associated with an increase in the adhesive and proliferative properties of circulating EPC in patients with CHF.

Aged↗

PubMed2005

Circulating erythropoietin levels and prognosis in patients with congestive heart failure: comparison with neurohormonal and inflammatory markers.

BACKGROUND: Considerable morbidity and mortality are still associated with congestive heart failure (CHF) syndromes, despite improvement in therapy. Activation of neurohormonal, inflammatory, and oxidative mechanisms has been shown to contribute to the significant morbidity and mortality. Erythropoietin (EPO) is a cytokine known to regulate erythroid proliferation, attenuate apoptosis and oxidative stress, and promote angiogenesis. We prospectively evaluated the predictive value of baseline EPO, N-terminal pro-B-type natriuretic peptide, and C-reactive protein levels in patients with clinically controlled chronic CHF. METHODS: One hundred eighty-eight outpatients from a CHF clinic had baseline assessment of EPO, N-terminal pro-B-type natriuretic peptide, and C-reactive protein levels and a complete clinical data profile. These patients were followed up for 24 months for any hospitalization due to CHF or mortality. RESULTS: Circulating EPO levels were higher in CHF patients and increased in subjects with higher New York Heart Association scores. Levels of EPO (at a cutoff of 23 mU/mL) and N-terminal pro-B-type natriuretic peptide (cutoff at the median of 1556 pg/mL) were found to be strong predictors of mortality and CHF hospitalization, whereas C-reactive protein levels (cutoff of 10 mg/L) predicted CHF hospitalizations but not mortality. Left ventricular ejection fraction was found to be a predictor of mortality but not of CHF hospitalizations. Serum levels of EPO were significantly correlated with N-terminal pro-B-type natriuretic peptide and C-reactive protein levels but not with left ventricular ejection fraction. CONCLUSION: If confirmed in large-scale clinical studies, determination of circulating EPO levels may aid in predicting morbidity and mortality in patients with clinically controlled congestive CHF.

Aged↗

PubMed2005

A functional role for inducible costimulator (ICOS) in atherosclerosis.

BACKGROUND: Lymphocytes appear to influence atherosclerosis by altering cytokine production. Whereas primary lymphocyte activation requires T cell receptor ligation, costimulatory signals also appear requisite for generation of a functional T cell response. Inducible costimulator (ICOS) is a newly discovered T cell molecule with a dual role in immune mediated disorders. Herein, we tested the importance of ICOS in atherosclerosis. METHODS AND RESULTS: Atherosclerotic plaques from ApoE-KO mice were studied immunohistochemically for the presence and localization of ICOS and its receptors and its expression in splenocytes. ApoE-KO mice were immunized with human ICOS/Fc-chimera or non-fused Fc and either provided a chow diet for 6 weeks, or a high fat diet for 8 weeks. ICOS and its ligand were abundantly expressed within plaques from ApoE-KO mice: Spleen cells from atherosclerotic mice exhibited lowered constitutive expression of ICOS yet priming with oxLDL enhanced ICOS expression dose-dependently. In mice induced to develop fatty streaks and to generate ICOS blocking antibodies, early atherosclerosis was increased by approximately 77% whereas upon inducing more advanced lesions, the increase in plaque area upon ICOS blockade group was approximately 36%. IFN-gamma secretion by oxLDL-primed splenocytes in ICOS-immunized mice increased whereas IL-10 secretion diminished as compared to control animals. A similar trend in cytokine production was evident in the lesion by immunohistochemistry. CONCLUSION: ICOS appears as an influential costimulatory pathway in atherosclerosis that may play a protective rather that a proatherogenic role.

Animals↗

PubMed2005

The involvement of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in atherosclerosis.

OBJECTIVES: Herein, we determined the significance of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in atherosclerotic vascular disease. BACKGROUND: Inflammation is associated with the pathogenesis of atherosclerosis. The TNF-related apoptosis-inducing ligand/APO-2L, a member of the TNF superfamily, has a role in apoptosis induction and is recognized for its immunomodulatory properties. METHODS: Stable and vulnerable atherosclerotic human plaques and aortas from atherosclerotic mice were assayed for the presence of TRAIL, and its inducibility was assayed by immunoblot and real-time polymerase chain reaction on peripheral mononuclear cells incubated with oxidized low-density lipoprotein (oxLDL). Enzyme-linked immunosorbent assay was used for the determination of soluble TRAIL levels in atherosclerotic patients. RESULTS: Tumor necrosis factor-related apoptosis-inducing ligand is present in stable atherosclerotic lesions, is increased in vulnerable plaques, and is found to colocalize with CD3 cells and oxLDL. The TNF-related apoptosis-inducing ligand messenger ribonucleic acid (mRNA) and protein expression was up-regulated in peripheral blood mononuclear cells after incubation with oxLDL. Serum levels of soluble TRAIL but not TNF-alpha or Fas-ligand were reduced significantly in patients with unstable angina as compared with patients with stable atherosclerotic disease and healthy subjects. A negative correlation was demonstrated between soluble TRAIL and C-reactive protein levels but not with levels of mRNA of TRAIL in peripheral blood mononuclear cells. CONCLUSIONS: Tumor necrosis factor-related apoptosis-inducing ligand is expressed in plaque-infiltrating CD3 cells and induced by oxLDL, whereas levels of soluble TRAIL are reduced in patients with acute coronary syndromes and negatively correlate with C-reactive protein levels. These results support a possible role for TRAIL in atherosclerosis.

Animals↗

PubMed2005

The effect of tyrphostin AG-556 on intimal thickening in a mouse model of arterial injury.

BACKGROUND: Inflammation has been shown to play an important role in promoting the response to arterial injury and proinflammatory cytokines, such as tumor necrosis factor (TNF) alpha, are candidate mediators. AG-556 is a tyrosine kinase inhibitor proven to be effective in a model of multiple sclerosis-like syndrome in mice due to its immunomodulating effect. In the current study, we investigated the effect of the tyrphostin AG-556 on neointimal thickening and cytokine profile in a model of arterial injury in the mouse. METHODS: Injury was induced by external cuff placement on the left femoral artery of wild-type C57BL/6 mice. AG-556 dissolved in DMSO was injected intraperitoneally daily to the injured mice in a dosage of 2 mg/mouse. Control mice received DMSO injections. Histological analysis was carried out to assess neointimal formation. Splenocytes were cultured in the absence and presence of a mitogen for evaluation of thymidine incorporation and cytokine production. RESULTS: AG-556 treatment significantly attenuated intimal thickening (43,000+/-17,000 microm2; n=11) when compared to DMSO administration (286,000+/-127,000 microm2; n=10; P<0.05). Basal interferon-gamma production by splenocytes from AG-556-treated mice was increased by approximately 20-fold in comparison with levels in DMSO-treated animals, whereas Con-A induced secretion of the cytokine was similar between both groups. Levels of TNF-alpha, IL-4 and IL-10 in the culture supernatant from treated and non-treated animals did not differ significantly. CONCLUSION: The tyrosine kinase inhibitor AG-556 may have a role in the reduction of intimal thickening. The effect could be mediated via an immune modulating effect involving a significant increase in the smooth muscle cell inhibitory cytokine IFN-gamma.

Animals↗

PubMed2005

Circulating matrix metalloproteinase-2 but not matrix metalloproteinase-3, matrix metalloproteinase-9, or tissue inhibitor of metalloproteinase-1 predicts outcome in patients with congestive heart failure.

BACKGROUND: Extracellular matrix remodeling is thought to play an important role in the progression of heart failure (HF). Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are matrix-degrading enzymes that have been demonstrated to influence left ventricular properties and serve as targets of potential anti-remodeling agents. Herein we evaluated the potential significance of circulating MMP and TIMP levels in patients with congestive HF (CHF) speculating it may assume prognostic value. METHODS: Serum samples were obtained from 88 consecutive patients attending the outpatient HF clinic and analyzed for MMP-2, -3, -9, and TIMP-1 as well as N-terminal probrain natriuretic peptide (NT-ProBNP). Patients were followed up for the occurrence of either mortality or hospitalizations due to CHF or either of each. RESULTS: Circulating levels of MMP-2, -9, and TIMP-1 but not of MMP-3 were increased in patients with CHF as compared with age-matched controls. Only MMP-2 and NT-ProBNP levels correlated significantly with New York Heart Association class. Matrix metalloproteinase-2 and NT-ProBNP levels did not correlate. Patients with circulating MMP-2 above 352 ng/mL were 4.2 times more likely to die, 2.2 times more likely to be hospitalized because of CHF, and 2.3 times more likely to experience either of the 2 end points as compared with patients with MMP-2 concentrations below this threshold. Both MMP-2 and NT-ProBNP were found to be independent predictors of mortality over a 24-month follow-up period. CONCLUSIONS: Matrix metalloproteinase-2 but not MMP-3, -9, or TIMP-1 serum levels is an independent predictor of mortality in patients with CHF.

Adult↗

PubMed2005

Serum levels of interleukin-18 in patients with stable and unstable angina pectoris.

Recent evidence suggests that atherosclerosis is an inflammatory disorder in which cytokines appear to play an important role. Special attention centered over the possible contribution of cytokines to the destabilization of the plaque. IL-18 is a proinflammatory cytokine of the IL-1 family, recognized for its ability to promote IFN-gamma secretion. It has recently been detected in human plaques and its administration was associated with increased atherosclerosis in apolipoprotein E (apoE) mice concomitant with an increase in plaque infiltrating inflammatory cells. In our study, we investigated whether patients with established atherosclerosis, with either stable or unstable angina, possessed high levels of IL-18. Patients with stable angina (n=48) were from the outpatient clinic whereas patients with unstable angina (n=73) were recruited upon admission and prior to performance of coronary angiography. Control patients (n=19) were healthy subjects with no evidence of coronary artery disease. Serum levels of IL-18 were assayed by ELISA. Patients with stable and unstable angina exhibited higher serum levels of IL-18 (77.1+/-7.2 and 61.5+/-5.1 pg/ml, respectively) in comparison to control subjects (p=0.002 and p=0.02, respectively). However, levels of IL-18 did not differ significantly between patients with stable and unstable angina. No differences were evident in the serum concentrations of IL-18 in patients with unstable angina (n=17) upon admission and 1-3 months later when the angina was already controlled. Although IL-18 serum levels appear elevated in the presence of coronary atherosclerosis, there is no evidence to associate this progression towards plaque instability.

Adult↗

PubMed2005

Erythropoietin in heart failure.

The incidence of both congestive heart failure (CHF) and end-stage renal disease both are increasing. Anemia is common in both conditions and is associated with a marked increase in mortality and morbidity in both CHF and chronic kidney insufficiency (CKI). Each of these 3 conditions can cause or worsen the other 2. In other words, a vicious circle frequently is present in which CHF can cause or worsen both anemia and CKI, in which CKI can cause or worsen both anemia and CHF, and in which anemia can cause or worsen both CHF and CKI. We have called this vicious circle the cardio renal anemia syndrome. Optimal treatment of CHF with all the recommended CHF medications at their recommended doses will, in our experience, frequently fail to improve the CHF and CKI if anemia is present and is not corrected. On the other hand, correction of the anemia with subcutaneous erythropoietin and intravenous iron has caused a great improvement in the CHF including a marked improvement in patient and cardiac function and a marked reduction in the need for hospitalization and for high-dose diuretics. It also frequently has caused renal function to improve or at least stabilize. In addition, patients' quality of life and exercise capacity also have improved with the correction of the anemia. In CKI patients, anemia also may play an important role in increasing the risk for death, coronary heart disease, stroke, and progression to end-stage renal disease. Erythropoietin may have a direct positive effect on the heart and brain unrelated to correction of the anemia by reducing cell apoptosis and by increasing neovascularization, both of which could prevent tissue damage. This could have profound therapeutic implications not only in CHF but in the future treatment of myocardial infarction, coronary heart disease, strokes, and renal failure.

Age Factors↗

PubMed2005

Transfer of endothelial progenitor cells improves myocardial performance in rats with dilated cardiomyopathy induced following experimental myocarditis.

Endothelial progenitor cells (EPCs) home to sites of tissue injury and differentiate into mature endothelial cells. Their transfer feasibility has been proven in models of hindlimb ischemia and myocardial infarction. We investigated, the effect of delivery of spleen-derived EPC in a rat model of inflammatory-mediated myocardial damage. Male Lewis rats (N=25) were immunized against myosin. Healthy donor Lewis rats were sacrificed, their spleens harvested, separated on Ficoll gradient centrifugation, and grown on fibronectin coated plates with endothelial cell medium for 5 days. Ten days after myosin immunization, spleen cell derived EPC were collected, and labeled 2 x 10(7) cells per rat were injected into the femoral vein of diseased rats. Cell transplantation was repeated twice, 2 and 4 weeks after initial cell transfer. Rats with inflammatory-mediated cardiomyopathy exhibited a significant mobilization of EPC from the bone marrow to the periphery and their ability to adhere to fibronectin, mature endothelial cells and cultured cardiomyocytes was significantly reduced when compared to healthy rats. Transfer of EPC resulted in a functional improvement in cardiac performance evident by higher fractional shortening by echocardiography (a 15% increase). Histological studies exhibited reduced scar tissue and thickened ventricular walls in rats receiving EPC as compared with untreated animals. EPC transfer is effective in attenuating myocardial damage in a model of non-ischemic dilated cardiomyopathy.

Animals↗

PubMed2005

Clinical value of 16-slice multi-detector CT compared to invasive coronary angiography.

BACKGROUND: Multi-detector row spiral CT (MDCT) can be applied as a noninvasive tool for the assessment of coronary artery stenoses. Few, confounding reports have been published using 16 detector rows. The aim of the present study was to determine the accuracy of 16-detector row MDCT for the detection of significant stenoses in the coronary arteries, in comparison to conventional invasive coronary angiography. METHODS: Twenty-two patients with suspected coronary artery disease, were prospectively evaluated by 16-slice retrospectively ECG-gated CT coronary angiography and quantitative invasive coronary angiography. The findings were compared for the detection of significant coronary artery stenoses (>50%) in all segments with diameter >1.5 mm. RESULTS: MDCT correctly classified all 14 patients (100%) that were found to have significant coronary artery disease on conventional angiography. Overall, 288 segments were included in the analysis, regardless of their image quality. Significant stenoses were detected in 24 segments by CT and in 28 segments by conventional angiography. Out of 260 segments that were negative for significant stenoses on conventional angiography, 255 were correctly identified on CT. The sensitivity, specificity, positive and negative predictive values were 86, 98, 83 and 98%, respectively. MDCT also revealed supplementary findings that invasive angiography was unable to visualize, including anomalous vessel course, the course of vessels filling via collaterals, intramyocardial course of vessels and non-stenotic plaques. CONCLUSIONS: MDCT coronary angiography utilizing 16-detector rows shows promising results for reliable detection of coronary artery stenoses and particularly for ruling out significant disease.

Adult↗

PubMed2005

Functional T-lymphocyte dichotomy in the peripheral blood of patients with unstable angina.

OBJECTIVES: Herein, we investigated the percentage of T-helper (Th1) and Th2 cells among the general T-cell population in the peripheral blood of patients with stable angina (SA) and unstable angina (UA). BACKGROUND: Recent evidence suggests that Th1 cells and the cytokines that they secrete (especially IFN-gamma) have a role in the activation of macrophages, promotion of clot formation and destabilization of atherosclerotic plaques. Thus, Th1 cytokines may contribute to the initiation and progression of UA. In contrast, cytokines secreted by Th2 cells (e.g. IL-10) are known to inhibit activation and proliferation of Th1 cells and the secretion of IFN-gamma, lysosomal enzymes and metalloproteinases. Therefore, we sought to examine whether the ratio of IFN-gamma to IL-10 secreting cells is altered in patients with UA. METHODS: The percentage of Th1 and Th2 cells among the general T-cell population was determined by fluorescent intracellular cytokine staining (IFN-gamma and IL-10, out of the total CD3 positive cells). RESULTS: The percentage of T-cells positive for intracellular IFN-gamma was significantly higher in patients with UA (n = 22) in comparison with SA (n = 20) patients (39.0+/-2.8% and 29.6+/-2.7%, respectively. P = 0.02). There was no significant difference in intracellular IL-10 positive cells between the two groups. In addition, there was no significant difference in the ratio between the intracellular IFN-gamma positive cells and the intracellular IL-10 positive cells. CONCLUSIONS: There is an increased activity of Th1 cells in patients with UA in comparison with patients with SA. There is no evidence of heightened activity of Th2 cells in either group. Thus, IFN-gamma secreted by peripheral blood T-lymphocytes,may be an important immunomodulator contributing to destabilization of the atheromatous plaque lying at the base of the etiopathogenesis of unstable angina.

Aged↗

PubMed2005

Anaemia as a contributor to morbidity and mortality in congestive heart failure.

Anaemia is present in approximately 40% of cases of congestive heart failure (CHF) and is associated with a higher mortality, a lower left ventricular ejection fraction, a lower cardiac functional status, a higher rate of hospitalization, signs of malnutrition, a lower exercise capacity, a progressive fall in renal function, an increased need for high dose diuretics, hyponatraemia, an increased plasma volume, a reduced red cell volume and a lower quality of life. In both uncontrolled and controlled studies, correction of the anaemia with subcutaneous erythropoietin and, in some cases, with the addition of intravenous iron, has been shown to improve these parameters. A vicious circle is present between CHF, chronic kidney insufficiency (CKI) and anaemia, each capable of causing or being caused by the other, the so-called cardio renal syndrome. If larger randomized, controlled, double-blind studies confirm these observations, correction of the anaemia may prove to be a useful addition to the prevention and progression of both CHF and CKI. Cooperation between nephrologists, cardiologists and other internists to identify and treat these anaemic CHF patients early will help prevent progression of both the cardiac and renal disease.

Anemia↗

PubMed2004

Temporal association between circulating proteolytic, inflammatory and neurohormonal markers in patients with coronary ectasia.

BACKGROUND: The prevalence of coronary ectasia (CE) appears to rise in recent years. However, the pathogenetic mechanisms that underlie this entity are not understood. We hypothesized that dysregulation of circulating matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) contributes to ectasia formation. We also evaluated the association of MMP with inflammatory or the neurohormonal markers. METHODS: We screened coronary angiographic procedures conducted in our hospital. Thirty-four patients with CEs were identified; 17 with a single ectasia and 17 with generalized ectasias. Two control groups; patients with atherosclerotic coronary disease (n=26) and patients with normal coronary arteries (n=27) were chosen randomly. Serum levels of MMP-2, MMP-3 and TIMP-1 were determined by ELISA. Pro B-type natriuretic peptide (proBNP) and high sensitivity C-reactive protein (hsCRP) serum levels were also measured. RESULTS: Serum levels of MMP-2, MMP-3, TIMP-1, proBNP and hsCRP did not differ between the three groups of patients. However, subgroup analysis demonstrated that MMP-3 level is significantly lower in patients with generalized CEs compared to those with single vessel ectasia. We also found a statistically significant correlation between proBNP and MMP-2/TIMP-1 (for MMP-2: r(2)=0.3, p=0.003 and for TIMP-1 r(2)=0.42, p<0.000l). By performing subgroup analysis we found that this correlation is only demonstrated in patients with CEs. No correlation was demonstrated between hsCRP and MMPs/TIMP. CONCLUSIONS: These observations suggest that MMP/TIMP imbalance is present in patients with generalized CE and may contribute to ectasia formation. This imbalance could be mediated by BNP.

Aged↗

PubMed2004

Effects of treatment with epoetin beta on outcomes in patients with anaemia and chronic heart failure.

UNLABELLED: Anaemia is frequently found in patients with chronic heart failure (CHF) and has been associated with an increase in mortality and morbidity, impaired cardiac and renal function and a reduced quality of life (QoL) compared with non-anaemic CHF patients. Correction of anaemia with recombinant human erythropoietin (epoetin) has been associated with an improvement in CHF in both controlled and uncontrolled studies. The present study describes our findings in a series of 78 consecutive patients with symptomatic CHF and anaemia (haemoglobin (Hb) level <12.0 g/dl) treated with epoetin beta and, if necessary, intravenous iron sucrose. Over a mean observation period of 20.7 +/- 12.1 months, mean Hb levels increased from 10.2 +/- 1.1 to 13.5 +/- 1.2 g/dl, p < 0.01. New York Heart Association (NYHA) functional class, left ventricular ejection fraction (LVEF) were significantly improved and the number of hospitalizations was significantly reduced with the period before treatment (all p < 0.01). Serum creatinine and creatinine clearance (CCr) were 2.2 +/- 0.9 mg/dl and 32.5 +/- 26.5 ml/min, respectively, at baseline, and remained stable over the observation period. Interestingly, >90% of the patients had concomitant mild-to-moderate chronic kidney disease at baseline and study end (CKD), as defined by the accepted diagnostic criterion of a CCr <60 ml/min. CONCLUSIONS: The correction of the anaemia with epoetin beta together with initial intravenous iron supplementation, resulted in significant improvements in NYHA class and cardiac function, and a reduction in hospitalization rate. Moreover, renal function was maintained stable in most patients.

Aged↗

PubMed2004

The interaction between heart failure, renal failure and anemia - the cardio-renal anemia syndrome.

BACKGROUND: Many patients with congestive heart failure (CHF) have chronic kidney insufficiency (CKI) and anemia. AIMS: The purpose of this review is to clarify the relationship between these three factors and to study the effect of correction of anemia in CHF and CKI. FINDINGS: Anemia, CHF and CKI are each capable of causing or worsening each other. Thus they form a vicious circle which can result in progressive CHF, CKI and anemia. Aggressive therapy of CHF, CKI and control of the associated anemia with erythropoietin and i.v. iron can prevent the progression of CHF and CKI, reduce hospitalization, and improve quality of life. CONCLUSION: CHF patients are a major source of end-stage renal failure patients and deserve special attention. If treated well and early, progressive heart failure and renal failure can be prevented. Cooperation between nephrologists, cardiologists, and other internists will improve the care of all three conditions and prevent their progression.

Anemia↗

PubMed2004

L-arginine attenuates lymphocyte activation and anti-oxidized LDL antibody levels in patients undergoing angioplasty.

BACKGROUND: Patients with acute coronary syndromes exhibit evidence of peripheral T lymphocyte activation, elevated acute phase proteins and enhanced oxidative stress. Nitric oxide (NO) has been recognized as one of the relaxant factors synthesized and released by normal endothelium, and acts as a double-edged sword on the immune system. L-arginine ameliorates experimental atherosclerosis and restenosis as well as endothelial dysfunction. We sought to investigate the effect of L-arginine administration on the extent of lymphocyte activation and anti-oxLDL antibodies in patients with unstable angina undergoing PCI with stent placement. METHODS: Patients with unstable angina were randomized to treatment with L-arginine (6g per day; n = 13) or none (n = 16) for 1 month starting immediately on the day of stent deployment. Lymphocyte activation was assayed by FACS employing double staining with a common lymphocyte marker (CD3) and an activation marker HLA-DR, on the day of the procedure and 1 month later. Anti-oxLDL antibodies were assayed by ELISA. RESULTS: Patients with unstable angina not receiving L-arginine exhibited a significant 43% rise in the percentage of activated peripheral T lymphocytes, 1 month after stent deployment. Patients treated with L-arginine exhibited a fall albeit not significant in the fraction of peripheral lymphocytes bearing the activation marker. Antibodies to anti-oxLDL rose significantly between baseline and 1 month follow-up. L-arginine treatment significantly attenuated the rise in anti-oxLDL antibody levels. CONCLUSION: L-arginine attenuates the systemic rise in peripheral lymphocyte activation and oxidative stress markers induced by vessel wall injury following PCI. These effects may contribute to a favorable effect of the drug in patients with acute coronary syndromes undergoing PCI.

Aged↗

PubMed2004

Zinc reduces intimal hyperplasia in the rat carotid injury model.

BACKGROUND: The response to arterial injury following balloon dilatation is known to involve proliferative and inflammatory processes. The current widespread use of stents to maintain arterial patency not only does not eliminate but possibly exaggerates the proliferative and inflammatory phenotype and although drug-eluting stents are available, their long-term safety is yet to be determined. Zinc is a trace element that serves as a cofactor of many enzymes. Interestingly, it has been shown to have anti-inflammatory and anti-proliferative properties. We thus sought to investigate its effect on smooth muscle cell proliferation and intimal thickening in the rat carotid artery injury model. METHODS AND RESULTS: Smooth muscle cells (SMC) were cultured from carotid arteries of rats and proliferation was assessed by thymidine incorporation after exposure to different concentrations of zinc. Next, carotid artery injury was induced in rats by balloon dilatation and they were either treated with I.P injections of zinc or PBS for 2 weeks until sacrifice for assessment of neointimal formation and lumen area. Zinc inhibited in vitro SMC proliferation in a dose-dependent manner. In vivo, zinc treatment resulted in a 50% reduction in neointimal area and a significant decrease in neointimal/media ratio with no significant change in lumen area. CONCLUSION: Thus, zinc appears to reduce neointimal growth and should be tested by local delivery systems including stent coatings.

Animals↗

PubMed2004

Circulating endothelial progenitor cells in patients with unstable angina: association with systemic inflammation.

BACKGROUND: Endothelial progenitor cells (EPC) are present in peripheral blood and can develop a functional endothelial phenotype. The number and function of circulating EPCs are altered in atherosclerosis, diabetes, and after myocardial infarction and EPCs have been shown to promote postnatal angiogenesis and vasculogenesis. We investigated the number and adhesive properties of EPCs from patients with unstable angina and no evidence of cardiac necrosis. METHODS AND RESULTS: Patients were selected with unstable angina (n=29) and no evidence of cardiac necrosis, and controls with stable angina (n=12) and atherosclerotic risk factors, medication use, and coronary vessel involvement similar to patients. Circulating EPC numbers were determined by colony-forming unit assay and their adhesive properties were evaluated by EPC capacity to bind immobilised fibronectin. High-sensitivity C-reactive protein (hsCRP) was determined in all patients. Circulating EPCs were significantly increased in patients with unstable as compared with stable angina (24.5+/-2.6 vs. 13.3+/-2.9, respectively). Seven unstable angina patients followed up for 3 months after clinical stabilisation exhibited a reduction of close to 50% in circulating EPC numbers. The adhesive capacity of EPCs from patients with unstable and stable angina did not differ. A positive correlation was found between systemic CRP levels and circulating EPC numbers, but not their adhesive capacity. CONCLUSION: Patients with unstable angina and no evidence of cardiac necrosis exhibited increased circulating EPCs. Systemic inflammation, in addition to recognised growth factors, could play a role in the peripheral mobilisation of EPCs in patients with anginal syndromes.

Angina, Unstable↗