Recombinant human interleukin-10 inhibits proliferation of vascular smooth muscle cells stimulated by advanced glycation end products and neointima hyperplasia after carotid injury in the rat.
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The purposes of this study was to determine the effects of recombinant human interleukin-10 (rhIL-10) on proliferation of vascular smooth muscle cells (VSMCs) stimulated by advanced glycation end products (AGE) and neointima hyperplasia after rat carotid arterial injury. Rat aortic VSMCs were cultured and treated with rhIL-10 or AGE respectively, and then co-treated with rhIL-10 and AGE. Proliferation of VSMCs was quantified by colormetric assay. Cell cycle analysis was performed by flow cytomertry. Sprague-Dawley rats were treated with recombinant human IL-10 (rhIL-10) for 3 d after carotid arteries injury. The ratio of neointima to media area at the site of arterial injury was measured 28 d after balloon injury. The p44/42 MAPK activity was evaluated by the immunoblotting technique using anti-p44/42 phospho-MAPK antibody. Compared to control, AGE stimulated VSMCs proliferation. rhIL-10 alone had no effect on VSMCs growth. With AGE stimulation, rhIL-10, at dose as low as 10 ng/ml, inhibited VSMCs growth (P<0.05). The cell number in G(0)/G(1) phase of AGE and rhIL-10 co-treatment group was higher than that of AGE treatment alone (P<0.01) by flow cytometry analysis. Compared with the control group of neointima hyperplasia in rats, the ratio of neointima to media area of recombinant human IL-10 group was reduced by 45% (P<0.01). The p44/42 MAPK activity was significantly enhanced by AGE. The AGE effects were opposed by rhIL-10. The anti-inflammatory cytokine rhIL-10 inhibits AGE-induced VSMCs proliferation. Recombinant human IL-10 also inhibited neointima hyperplasia after carotid artery injury in rats. The results suggest the possibility that recombinant human IL-10, as a potential therapeutic approach, prevents neointimal hyperplasia. (+info)
Adiponectin concentrations as a criterion of metabolic control in persons with type 2 diabetes mellitus?
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Adiponectin (ADP) is an adipocytokin with many antiatherogenic properties; its decreased level is associated with numerous atherogenic diseases and syndromes (e.g. diabetes mellitus (DM), dyslipidemia, endothelial dysfunction, hypertension, and obesity). Decreased ADP values in blood may be an independent risk factor of atherosclerotic (ATS) complications. AIM OF THE STUDY: 1) Do persons with type 2 diabetes have lower ADP values than individuals without DM but with a high risk of ATS complications? 2) Do ADP values differ between persons with well controlled and persons with uncontrolled type 2 diabetes? We examined 109 patients of the Metabolic Center of Hospital Sternberk. Out of them, 58 had type 2 diabetes, others were individuals with variously expressed risk factors of early atherosclerosis (obesity, hypertension, age, family history, smoking, dyslipidemia, etc.). In all persons under this study the following parameters were determined in peripheral venous blood: adiponectin, resistin, leptin, ObRe, cholesterol, HDL-cholesterol, triacylglycerols, glucose, HbA1c, creatinine, urea, ALT, AST, CRP, homocysteine, thrombocyte aggregation after CPG induction. The whole group was divided according to the presence of type 2DM into two subgroups; persons with diabetes were divided into the well controlled and uncontrolled subgroups. All data obtained were processed statistically using the software SPSS for Windows and Medcalc. The adiponectin/BMI index correlated negatively with HbA1c value (correlation coefficient -0.37, p = 0.00053), triacylglycerols (-0.4, p = 0.000001), P-glucose (-0.3, p = 0.0017), uricemia (-0.35, p = 0.0007) and positively with HDL-cholesterol value (0.6, p=0.00001). Women had higher adiponectin values than men. Persons with hypertension and with diabetes mellitus, individuals with atherogenic lipotype or persons with inflammation signs had lower values than individuals without these diseases and syndromes. Persons with wellcontrolled diabetes mellitus had higher values than persons with uncontrolled diabetes (medians of the adiponectin/BMI index 9.7 vs. 6.7, p < 0.01). Persons with type 2 diabetes mellitus have lower ADP values than persons with a high ATS risk without diabetes mellitus. Persons with wellcontrolled diabetes mellitus (DM) and with satisfactory compensation have significantly higher ADP levels (independently of other metabolic parameters of DM control). ADP may be a new marker of metabolic control in persons with a high risk of atherosclerotic complications. (+info)
The importance of indicators of the initial phase of atherosclerosis in patients with microvascular angina.
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Endothelial dysfunction (ED) is generally considered to be the initial step in the progression to atherosclerosis but there is still much uncertainty about the role of the microvascular form of angina in patients with a normal coronary angiogram with regard to ED. The authors investigated the extent of endothelial perturbation and thereby whether the microvascular form of angina precedens macroscopic atherosclerosis by means of non-invasive ultrasound measurement of the intima-media thickening (IMT) in common carotid artery and flow mediated dilatation (FMD) in the brachial artery. 28 patients with stable angina with positive exercise test and ST segment depression (22 females, 6 males, average age 54 years) were compared with a control group consisting of 28 patients with no clinical signs of coronary artery disease (18 females, 10 males, average age 53 years). No significant difference in FMD% (7.3 vs. 10.8, p = 0.07) was found between the groups, though specific measurements (average dilatation of the brachial artery induced by ischemic insult, peak blood flow and peak hyperemic flow) differed considerably. Also IMT did not vary significantly between the groups (0.74 vs. 0.65, p = 0.08). In patients with IMT > 0.8 mm (6 patients in each group) a significant decrease of FMD was found as compared with patients with normal IMT (p < 0.05). It was concluded that in patients with increased IMT an inverse relationship between FMD and IMT exists both in patients with microvascular angina and in the healthy control subjects whereas in the group of patients with normal IMT no ED was demonstrated. This supports the hypothesis that the microvascular form of angina is the early stage of coronary artery atherosclerosis and this escapes angiographic recognition. (+info)
Loss of collagen XVIII enhances neovascularization and vascular permeability in atherosclerosis.
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BACKGROUND: Plaque neovascularization is thought to promote atherosclerosis; however, the mechanisms of its regulation are not understood. Collagen XVIII and its proteolytically released endostatin fragment are abundant proteoglycans in vascular basement membranes and the walls of major blood vessels. We hypothesized that collagen XVIII in the aortic wall inhibits the proliferation and intimal extension of vasa vasorum. METHODS AND RESULTS: To test our hypothesis, we bred collagen XVIII-knockout (Col18a1(-/-)) mice into the atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) strain. After 6 months on a cholesterol diet, aortas from ApoE(-/-);Col18a1(-/-) and ApoE(-/-);Col18a1(+/-) heterozygote mice showed increased atheroma coverage and enhanced lipid accumulation compared with wild-type littermates. We observed more extensive vasa vasorum and intimal neovascularization in knockout but not heterozygote aortas. Endothelial cells sprouting from Col18a1(-/-) aortas were increased compared with heterozygote and wild-type aortas. In contrast, vascular permeability of large and small blood vessels was enhanced with even heterozygous loss of collagen XVIII but was not suppressed by increasing serum endostatin to wild-type levels. CONCLUSIONS: Our results identify a previously unrecognized function for collagen XVIII that maintains vascular permeability. Loss of this basement membrane proteoglycan enhances angiogenesis and vascular permeability during atherosclerosis by distinct gene-dose-dependent mechanisms. (+info)
Protective effect of propylthiouracil independent of its hypothyroid effect on atherogenesis in cholesterol-fed rabbits: PTEN induction and inhibition of vascular smooth muscle cell proliferation and migration.
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BACKGROUND: Propylthiouracil (PTU) is used to treat hyperthyroid patients by its hypothyroid effect. PTU also is found to have potent antioxidant and immunosuppressive effects. These findings suggest that PTU may play a role in the prevention of atherosclerosis. METHODS AND RESULTS: This study evaluates the effect of PTU on atherosclerotic change in rabbits fed a high-cholesterol diet. The pronounced atherosclerotic lesions in the aortas of rabbits fed a 2% cholesterol diet for 12 weeks were significantly attenuated by the concurrent addition of 0.1% PTU to the drinking water. However, exogenous supplementation of thyroid hormone in hypothyroid PTU-treated rabbits did not abrogate the protective effect of PTU on atherogenesis. Immunohistochemical analysis showed that PTU administration apparently reduced the intimal smooth muscle cell/macrophage ratio in the atherosclerotic plaques of rabbits fed a 2% cholesterol diet. In vitro, the addition of PTU to the medium of cultured rat vascular smooth muscle cells led to a dose-dependent inhibition of cell proliferation and migration. Furthermore, this study confirmed that PTU dose-dependently increased expression of PTEN, a tumor suppressor gene known to be involved in the coordinate inhibition of VSMC proliferation and migration. CONCLUSIONS: This study demonstrated that PTU inhibited the development of atherosclerosis through a thyroid-independent mechanism that may be explained, at least in part, by the ability of PTU to inhibit vascular smooth muscle cell proliferation and migration. Furthermore, PTEN induction, via disruption of the phosphatidylinsitol 3-kinase-mediated pathway, plays a crucial role in mediating the inhibitory action on vascular smooth muscle cell proliferation and migration. (+info)
Association of mitral annulus calcification, aortic valve calcification with carotid intima media thickness.
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BACKGROUND: Mitral annular calcification (MAC) and aortic annular calcification (AVC) may represent a manifestation of generalized atherosclerosis in the elderly. Alterations in vascular structure, as indexed by the intima media thickness (IMT), are also recognized as independent predictors of adverse cardiovascular outcomes. AIM: To examine the relationship between the degree of calcification at mitral and/or aortic valve annulus and large artery structure (thickness). METHODS: We evaluated 102 consecutive patients who underwent transthoracic echocardiography and carotid artery echoDoppler for various indications; variables measured were: systemic blood pressure (BP), pulse pressure (PP=SBP-DBP), body mass index (BMI), fasting glucose, total, HDL, LDL chlolesterol, triglycerides, cIMT. The patients were divided according to a grading of valvular/annular lesions independent scores based on acoustic densitometry: 1 = annular/valvular sclerosis/calcification absence; 2 = annular/valvular sclerosis; 3 = annular calcification; 4 = annular-valvular calcification; 5 = valvular calcification with no recognition of the leaflets. RESULTS: Patient score was the highest observed for either valvular/annulus. Mean cIMT increased linearly with increasing valvular calcification score, ranging from 3.9 +/- 0.48 mm in controls to 12.9 +/- 1.8 mm in those subjects scored 5 (p < 0.0001). In the first to fourth quartile of cIMT values the respective maximal percentual of score were: score 1: 76.1%, score 2: 70.1%, score 4: 54.3% and score 5: 69.5% (p > 0.0001). CONCLUSION: MAC and AVC score can identify subgroups of patients with different cIMT values which indicate different incidence and prevalence of systemic artery diseases. This data may confirm MAC-AVC as a useful important diagnostic parameter of systemic atherosclerotic disease. (+info)
Adiponectin, an adipocyte-derived protein.
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Adipose tissue is a hormonally active tissue, producing adipocytokines which may influence activity of other tissues. Adiponectin, abundantly present in the plasma increases insulin sensitivity by stimulating fatty acid oxidation, decreases plasma triglycerides and improves glucose metabolism. Adiponectin levels are inversely related to the degree of adiposity. Anorexia nervosa and type 1 diabetes are associated with increased plasma adiponectin levels and higher insulin sensitivity. Decreased plasma adiponectin levels were reported in insulin-resistant states, such as obesity and type 2 diabetes and in patients with coronary artery disease. Activity of adiponectin is associated with leptin, resistin and with steroid and thyroid hormones, glucocorticoids, NO and others. Adiponectin suppresses expression of extracellular matrix adhesive proteins in endothelial cells and atherosclerosis potentiating cytokines. Anti-atherogenic and anti-inflammatory properties of adiponectin and the ability to stimulate insulin sensitivity have made adiponectin an important object for physiological and pathophysiological studies with the aim of potential therapeutic applications. (+info)
Carotid plaque pathology: thrombosis, ulceration, and stroke pathogenesis.
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BACKGROUND AND PURPOSE: To determine the relationship between ulceration, thrombus, and calcification of carotid artery atherosclerotic plaques and symptoms of ipsilateral or contralateral stroke. METHODS: We compared microscopic plaque morphology from patients with and without stroke symptoms ipsilateral or contralateral to the plaque. Plaques were characterized for ulceration, thrombus, and calcification. We analyzed plaques from 241 subjects: 170 patients enrolled in the Asymptomatic Carotid Atherosclerosis Study (ACAS) and 71 patients enrolled in the North American Symptomatic Carotid Endarterectomy Trial (NASCET); 128 subjects had no history of stroke symptoms, 80 subjects had ipsilateral symptoms, and 33 had contralateral symptoms. RESULTS: Plaque ulceration was more common in plaques taken from symptomatic patients than those without symptoms (36% versus 14%; P<0.001); frequency of ulceration was similar for plaques associated with ipsilateral (34%) and contralateral (42%) symptoms. Thrombus was most common in plaques taken from patients with both ipsilateral symptoms and ulceration. The extent of calcification was unassociated with stroke symptoms. CONCLUSIONS: Carotid plaque ulceration and thrombosis are more prevalent in symptomatic patients. Ulceration is more common in symptomatic patients regardless of side of carotid symptoms, whereas thrombus is associated with ipsilateral symptoms and plaque ulceration. Preoperative identification of carotid ulceration and thrombus should lead to greater efficacy of stroke prevention by carotid endarterectomy. (+info)