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Biomedical subjects

Angelo Avogaro

Publications and source records attributed to Angelo Avogaro.

At least 19 recordsLinked to original sources
PubMed2006

Circulating CD34+ cells, metabolic syndrome, and cardiovascular risk.

AIMS: Circulating progenitor cells are believed to participate in cardiovascular (CV) homeostasis and their exhaustion has been linked to CV damage. As general agreement on their characterization is lacking, this work was carried out to assess the relationships between different antigenic profiles of progenitor cells and CV risk, with special regard to metabolic syndrome (MetSyn). METHODS AND RESULTS: CD34, CD133, and KDR were used to quantify circulating progenitors in 214 subjects at different levels of CV risk. In a cross-analysis of six different cell subtypes (CD34(+), CD133(+), CD34(+)CD133(+), CD34(+)KDR(+), CD133(+)KDR(+), and CD34(+)CD133(+)KDR(+)), CD34(+) progenitors showed the best correlation with CV parameters and risk estimates. Components of the MetSyn were all characterized by reduction of CD34(+) cells and acted synergistically in decreasing CD34(+) cell count. Moreover, CD34(+) cell count demonstrated a high performance in detecting high CV risk. CONCLUSION: These data demonstrate that CD34 identifies progenitor cells linked to CV risk, showing a close negative correlation between CD34(+) cells and CV risk, as well as a synergic detrimental effect of clustered metabolic components. Progenitor cell count may be used as a surrogate marker of CV risk, whereas extensive antigenic characterization may not be useful for this purpose.

Antigens, CD34↗
PubMed2006

Peripheral blood CD34+KDR+ endothelial progenitor cells are determinants of subclinical atherosclerosis in a middle-aged general population.

BACKGROUND AND PURPOSE: Disruption of the endothelial layer is the first step in the atherogenic process. Experimental studies have shown that endothelial progenitor cells (EPCs) are involved in endothelial homeostasis and repair. Conversely, EPC depletion has been demonstrated in the setting of established atherosclerotic diseases. With this background, we evaluated whether variations in the number of EPCs are associated with subclinical atherosclerosis in healthy subjects. METHODS: Carotid intima-media thickness (IMT), high-sensitive C-reactive protein (hsCRP), levels of circulating EPCs, and cardiovascular risk were compared in 137 healthy subjects. Six subpopulations of progenitor cells were determined by flow cytometry on the basis of the surface expression of CD34, CD133, and KDR antigens: CD34(+), CD133(+), CD34(+)CD133(+), CD34(+)KDR(+), CD133(+)KDR(+), and CD34(+)CD133(+)KDR(+). RESULTS: Among different antigenic profiles of EPCs, only CD34(+)KDR(+) cells were significantly reduced in subjects with increased IMT. Specifically, CD34(+)KDR(+) cells were inversely correlated with IMT, even after adjustment for hsCRP and 10-year Framingham risk and independently of other cardiovascular parameters. CONCLUSIONS: Depletion of CD34(+)KDR(+) EPCs is an independent predictor of early subclinical atherosclerosis in healthy subjects and may provide additional information beyond classic risk factors and inflammatory markers.

Adult↗
PubMed2006

Number and function of endothelial progenitor cells as a marker of severity for diabetic vasculopathy.

OBJECTIVE: Peripheral arterial disease (PAD) is a threatening complication of diabetes. As endothelial progenitor cells (EPCs) are involved in neovasculogenesis and maintenance of vascular homeostasis, their impairment may have a role in the pathogenesis of diabetic vasculopathy. This study aimed to establish whether number and function of EPCs correlate with PAD severity in type 2 diabetic patients. METHODS AND RESULTS: EPCs were defined by the expression of CD34, CD133 and KDR, and quantified by flow cytometry in 127 diabetic patients with and without PAD. PAD severity has been assessed as carotid atherosclerosis and clinical stage of leg atherosclerosis obliterans. Diabetic patients with PAD displayed a significant 53% reduction in circulating EPCs versus non-PAD patients, and EPC levels were negatively correlated with the degree of carotid stenosis and the stage of leg claudication. Moreover, the clonogenic and adhesion capacity of cultured EPCs were significantly lower in diabetic patients with PAD versus patients without. CONCLUSIONS: This study demonstrates that EPC decrease is related to PAD severity and that EPC function is altered in diabetic subjects with PAD, strengthening the pathogenetic role of EPC dysregulation in diabetic vasculopathy. EPC count may be considered a novel biological marker of peripheral atherosclerosis in diabetes.

Aged↗
PubMed2006

Insulin generates free radicals in human fibroblasts ex vivo by a protein kinase C-dependent mechanism, which is inhibited by pravastatin.

Insulin can generate oxygen free radicals. Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, exert a powerful antioxidant effect. The present study aimed to clarify the mechanisms through which insulin generates free radicals and to assess whether pravastatin modulates such effects. In cultured skin fibroblasts from human volunteers exposed to high insulin concentration, either in the presence or in the absence of pravastatin, insulin induced translocation of the p47(phox) subunit of NAD(P)H oxidase from the cytosol to the membrane and generation of radical oxygen species through a PKC delta-dependent mechanism. The insulin-induced translocation of p47(phox) was PKC delta dependent and attenuated by pravastatin, but independent of the activation of Akt and Rac1. Insulin-induced Akt phosphorylation was increased by pravastatin and ERK1/2 phosphorylation attenuated. The present study demonstrates a novel mechanism by which insulin stimulates the generation of free radicals in human fibroblasts, ex vivo. It involves phosphatidylinositol 3-kinase, PKC delta, and p47(phox) translocation and promotes ERK1/2 phosphorylation. Pravastatin inhibited radical oxygen species production by inhibiting PKC delta. These observations offer a robust explanation for the positive effects of pravastatin treatment in patients with insulin resistance syndrome.

Cells, Cultured↗
PubMed2006

Circulating progenitor cells are reduced in patients with severe lung disease.

Patients with chronic severe lung disease are prone to develop pulmonary vascular remodeling, possibly through pulmonary endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are involved in maintenance of endothelial homeostasis. The aim of this study was to assess whether obstructive and restrictive lung diseases are associated with modification of EPC number in peripheral blood. The study was cross-sectional and involved patients with obstructive (n = 15) and restrictive (n = 15) lung disease on oxygen therapy and 15 control subjects. Circulating EPCs were defined by the surface expression of CD34, CD133, and kinase-insert domain receptor. Results from spirometric tests, blood gas analyses, and blood cell counts have been related to EPC numbers. Patients with chronic hypoxia and severe lung disease showed lower levels of all progenitors than do control subjects. A consensual further reduction of EPC was found in restrictive patients in comparison with obstructive patients. Among restrictive patients, EPC reduction was related to reduced lung volumes and impaired alveolo-arterial diffusion, whereas progenitor cell levels were directly related to erythrocyte number. Considering obstructive patients, significant correlations were found between progenitor cell levels and bronchial obstruction and between progenitor cell levels and arterial oxygen tension. These findings demonstrate a reduction of EPCs in patients with chronic lung disease and long-lasting hypoxia. This alteration was more evident in restrictive patients and correlated to disease severity. Depletion of circulating EPCs may be involved in altered endothelial homeostasis of pulmonary circulation in these disorders.

Aged↗
PubMed2006

Genetic variability at the leptin receptor (LEPR) locus is a determinant of plasma fibrinogen and C-reactive protein levels.

OBJECTIVE: Cellular and animal studies suggest that leptin has proinflammatory and prothrombotic effects that could link increased adipose mass directly to atherogenesis. To investigate this hypothesis, we examined the effect of genetic variability at the leptin receptor (LEPR) locus on the plasma levels of fibrinogen and CRP--two markers of inflammation and susceptibility to atherosclerosis. METHODS AND RESULTS: Linkage disequilibrium analysis of 71 single-nucleotide polymorphisms (SNPs) spanning the LEPR locus revealed four haplotype blocks that could be tagged by 11 SNPs. In 630 healthy Caucasian individuals, variability in block #4 was significantly associated with plasma fibrinogen (p=0.005), accounting for 3% of its variance (r2=0.030). The same block was also associated with CRP levels (p=0.049, r2=0.022). The effect was strongest for two of the SNPs in this block. At rs3790432, fibrinogen was 10% higher in minor allele homozygotes than in major allele homozygotes and intermediate in heterozygotes (p=0.015). At rs1805096, it was 5% higher (p=0.007) and CRP 32% higher (p=0.011) in major allele homozygotes than in minor allele carriers. This pattern of association was also evident in the haplotype analysis. CONCLUSIONS: Association of leptin receptor variability with inflammatory traits supports the hypothesis that leptin may play a role in atherogenesis.

Adipose Tissue↗
PubMed2006

The under-use of statin in type 2 diabetic patients attending diabetic clinics in Italy.

BACKGROUND AND AIMS: The greatest decrease in mortality from cardiovascular disease (CAD) that can be achieved with 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) is seen in patients with the highest risk for CAD, such as diabetics. Yet, there is evidence for inadequate use of drug therapies to achieve lipid goals. Our aims were to: (1) assess the prevalence of statin use in patients attending diabetic clinics and (2) correlate the use of statins with their risk and clinical status. METHODS AND RESULTS: Of 9921 patients included, only 20.4% of them were receiving statin therapy. Statins were more progressively prescribed in those with risk factors additional to that of diabetes. Patients under statin treatment were older, mostly type 2 diabetics, more hypertensive and hyperlipidemic, had a higher prevalence of both macro- and microvascular disease. Among those with a total cholesterol concentration above 252 mg/dl, statin treatment was given only to 60% of diabetic patients with prior myocardial infarction, 56% of those with angina, 66% of those having had prior revascularization procedure, 54% of those with cerebrovascular disease and 51% of those with peripheral artery disease. CONCLUSIONS: At least in Italy, statins are not prescribed to the majority of diabetic patients, and a substantial proportion of patients not treated with statins present significant macro- and microvascular complications.

Adult↗
PubMed2006

Endothelial dysfunction in type 2 diabetes mellitus.

AIMS: Vascular endothelial cells play a major role in maintaining cardiovascular homeostasis in health. Diabetes mellitus (DM) substantially impairs the vasodilating properties of the endothelium and leads to endothelial dysfunction, which can thus be considered the first step in the progression of cardiovascular disease. The aim of the present study is to illustrate possible mechanisms responsible for endothelial dysfunction in DM. DATA SYNTHESIS: We have shown that NADPH oxidase gene expression is increased in circulating lymphomonocytes from patients with DM, and that this increased gene expression is dependent upon metabolic control. Hyperglycemia can mediate its adverse effects through the activation of protein kinase C. We have shown an increase in membrane-associated PKC beta 2 activity in monocytes from patients with DM. This activity was reduced by 40% in the euglycemic condition. Finally, we show a reduction of the circulating endothelial progenitor cells, a subset of bone marrow-derived endothelial-oriented stem cells, which can give rise to mature endothelial cells. CONCLUSION: Endothelial dysfunction, the initial step of the atherosclerotic process, is reversible. Thus, major efforts should be made to control not only hyperglycemia but also the other risk factors for cardiovascular disease, in order to prevent the onset of all these processes that eventually leads the diabetic patient to premature death.

Diabetes Complications↗
PubMed2006

Laparoscopic treatment of benign insulinomas localized in the body and tail of the pancreas: a single-center experience.

BACKGROUND: The increasingly widespread use of minimally invasive surgery has allowed surgeons to exploit this approach for complex procedures, such as pancreatic resections, though its actual role outside simple operations remains debated. METHODS: This is a study of 12 consecutive patients, 5 men and 7 women, with pancreatic insulinoma who were treated at our institution from 2000 to September 2005. All patients presented with typical symptoms and laboratory findings of hyperinsulinism and were good candidates for laparoscopic surgery. Preoperative diagnostic work-up, operating time, postoperative complication rate, length of hospital stayd and clinical outcome were assessed. RESULTS: Successful laparoscopic resection was performed in 11 out of 12 patients: 4 had tumor enucleation, and 7 had distal pancreatectomy; among these latter 5 had spleen-preserving distal pancreatectomy. In 1 case conversion to open surgery was necessary. Mean operative time was 170 minutes. The median tumor size was 18 mm, and all the insulinomas were benign. Four complications were observed in this group, and the median hospital stay was 8 days. CONCLUSIONS: The laparoscopic approach proved to be feasible and safe, although the average operative time was longer and demanded good surgical skills as well as precise localization of the tumor and definition of its nature. Tumors located in the body or tail of the pancreas that are benign in nature can better benefit of laparoscopic approach.

Adult↗
PubMed2006

A visfatin promoter polymorphism is associated with low-grade inflammation and type 2 diabetes.

Visfatin (also known as pre-B cell colony-enhancing factor, or PBEF) is a pro-inflammatory adipokine expressed predominantly in visceral fat. We investigated whether polymorphisms at the visfatin/PBEF locus influence the risk of type 2 diabetes (T2D). Linkage disequilibrium analysis of 52 single nucleotide polymorphisms spanning the entire gene (34.7 kb) plus 20.5 kb of the upstream region and 25.5 kb of the downstream region revealed a single haplotype block that could be tagged by seven single nucleotide polymorphisms. These seven tags were typed in a group of T2D patients (n = 814) and a group of non-diabetic controls (n = 320) of white origin. A significant association was observed at -948C>A, with minor allele frequencies of 0.157 in T2D cases and 0.119 in non-diabetic controls (p = 0.021). In a non-diabetic population (n = 630), the same -948 allele that conferred increased risk of T2D was significantly associated with higher plasma levels of fibrinogen and C-reactive protein (p = 0.0022 and 0.0038, respectively). However, no significant associations were observed with BMI, waist circumference, serum glucose levels, or fasting insulin levels. Our findings suggest that the visfatin/PBEF gene may play a role in determining T2D susceptibility, possibly by modulating chronic, low-grade inflammatory responses.

Adult↗
PubMed2006

Reduced expression of regulator of G-protein signaling 2 (RGS2) in hypertensive patients increases calcium mobilization and ERK1/2 phosphorylation induced by angiotensin II.

CONTEXT: RGS2 (regulators of G-protein signaling) is a negative regulator of Galphaq protein signaling, which mediates the action of several vasoconstrictors. RGS2-deficient mouse line exhibits a hypertensive phenotype and a prolonged response to vasoconstrictors. OBJECTIVE: To compare RGS2 expression in peripheral blood mononuclear cells (PBMs) and cultured fibroblasts from normotensive subjects and hypertensive patients. METHODS: PBMs were isolated from 100 controls and 150 essential hypertensives. Additionally, fibroblasts were isolated from skin biopsy of 11 normotensives and 12 hypertensives and cultured up to the third passage. Quantitative mRNA and protein RGS2 expression were performed by real-time quantitative reverse transcriptase-polymerase chain reaction and by immunoblotting, respectively. Free Ca measurement was performed in monolayers of 24-h serum-deprived cells, using FURA-2 AM. Phosphorylation of the extracellular signal-regulated kinases ERK1/2 was measured by immunoblotting. Polymorphism (C1114G) in the 3' untranslated region of the RGS2 gene was investigated by direct sequencing and real-time polymerase chain reaction (PCR). RESULTS: RGS2 mRNA expression was significantly lower in PBM and in fibroblasts from hypertensives, in comparison to normotensives. C1114G polymorphism was associated with RGS2 expression, with the lowest values in GG hypertensives. The 1114G allele frequency was increased in hypertensives compared with normotensives. Angiotensin II-stimulated intracellular Ca increase and ERK1/2 phosphorylation were higher in fibroblasts from hypertensive patients compared with control subjects, and in those with the G allele, independently of the blood pressure status. The angiotensin II-stimulated Ca mobilization and ERK1/2 phosphorylation were negatively correlated with RGS2 mRNA expression. CONCLUSION: Low expression of RGS2 contributes to increased G-protein-coupled signaling in hypertensive patients. The allele G is associated with low RGS2 expression and blood pressure increase in humans.

Adult↗
PubMed2006

Effects of different insulin regimes on postprandial myocardial perfusion defects in type 2 diabetic patients.

OBJECTIVE: Postprandial glycemia is an independent risk factor for cardiovascular disease that is more powerful than fasting glycemia and determines myocardial perfusion defects in type 2 diabetes. We examined the efficacy of two different insulin regimes (regular insulin and insulin analog) in controlling postprandial hyperglycemia and in preventing myocardial perfusion abnormalities. RESEARCH DESIGN AND METHODS: A total of 20 consecutive type 2 diabetic patients and 20 control subjects were enrolled in this randomized, three-way, cross-over, placebo-controlled study. Myocardial perfusion was assessed by myocardial contrast echocardiography (MCE) in fasting and postprandial (120 min) state. RESULTS: Insulin analog was associated with lower, but not statistically significant, postprandial glycemia than regular insulin (glucose increase: 116 +/- 8 vs. 136 +/- 5%, P = NS). However, the area under the curve following insulin analog was significantly lower than regular insulin (18,354 +/- 702 vs. 20,757 +/- 738 mg per 120 min, P = 0.032). Fasting myocardial flow velocity (beta), myocardial blood volume (MBV), and myocardial blood flow (MBF) did not differ between control and type 2 diabetic subjects. Postprandial beta (0.67 +/- 0.24 vs. 0.92 +/- 0.25, P < 0.01), MBV (8.4 +/- 2 vs. 10.9 +/- 1.2, P < 0.01), and MBF (5.6 +/- 2 vs. 9.9 +/- 2.8, P < 0.01) increased significantly in control subjects. In type 2 diabetes, during placebo in the postprandial state, beta increased (0.65 +/- 0.27 vs. 0.89 +/- 0.24, P < 0.01), while MBV (8.34 +/- 1.2 vs. 4.3 +/- 1.3, P < 0.01) and MBF (5.4 +/- 1.5 vs. 3.4 +/- 0.9, P < 0.01) decreased. Similar changes in MCE variables were observed after regular insulin: beta increased (0.65 +/- 0.22 vs. 0.92 +/- 0.12, P < 0.01) and MBV (8.2 +/- 2 vs. 5.2 +/- 1.16, P < 0.01) and MBF (5.4 +/- 1.9 vs. 4.2 +/- 0.86, P < 0.01) were reduced. After insulin analog, postprandial beta (0.66 +/- 0.18 vs. 0.9 +/- 0.18, P < 0.01), MBV (8.2 +/- 1.6 vs. 9.6 +/- 1.2, P < 0.01), and MBF (5.4 +/- 2 vs. 7.2 +/- 1.9, P < 0.01) increased. Values of postprandial MBV and MBF were higher after insulin analog than regular insulin treatment. CONCLUSIONS: Insulin analog partially reversed myocardial perfusion abnormalities observed in postprandial state by improving glucose control.

Area Under Curve↗