Percentage Of Lesion Area Research Articles

Interleukin 17 promotes atherosclerosis and protects against aneurysmal rupture

Interleukin 17 (IL17) is a unique cytokine produced by Th17 cells, a novel subset of T lymphocytes distinct from Th1 and Th2 cells. Atherosclerosis and aneurysm formation are inflammatory diseases in which Th1 cytokines play an important role. The role of IL17 in atherosclerosis is poorly defined, however, and its role in aneurysm formation is unknown. We investigated the effect of IL17 on atherosclerosis and aneurysm formation by crossing IL17 and ApoE deficient mice. Mice were then subjected to either 3 months of high fat diet or 4 weeks of high fat diet plus Ang II infusion. Aortic atherosclerosis, as defined as percent lesion area, was reduced in IL17−/−/ApoE−/− mice compared to ApoE−/− controls after 3 months of high fat diet (15% vs 20%, n=11, p=0.03) as well as after 4 weeks of high fat diet plus Ang II infusion (13% vs 21%, n=4–5, p=0.02). High fat diet plus Ang II infusion induced a similar degree of abdominal aortic aneurysm (AAA) formation but a greater incidence of death due to AAA rupture in IL17−/−/ApoE−/− mice compared to ApoE−/− controls (31% vs 7%, n=14–16). Thus, IL17 promoted atherosclerosis but protected against aneurysmal rupture. IL17 could therefore represent a novel therapeutic target for treatment of atherosclerosis but its effect on AAA rupture must be taken into consideration when designing strategies that target IL17. Supported by NIH Grants P01HL58000, R01HL39006, P01HL58000, and ACTSI TL1 RR025010.

Oxidative Stress and Compartment of Gene Expression Determine Proatherosclerotic Effects of Inducible Nitric Oxide Synthase

Genetic and pharmacological inhibition of inducible nitric oxide synthase (iNOS) decreases atherosclerosis development. Potential proatherogenic effects of iNOS include iNOS mediated oxidative stress and iNOS expression in different cellular compartments. Lesional iNOS can potentially produce nitric oxide radicals (NO), superoxide radicals (O2(-)), or both; these radicals may then react to form peroxynitrite. Alternatively, O2(-) radicals from oxidases co-expressed with iNOS could react with NO to produce peroxynitrite. Therefore, the expression profiles of the genes that modulate the redox system in different iNOS-expressing cell compartments may determine the role of iNOS in atherosclerosis. We used apoE (apoE(-/-)) and apoE/iNOS double knockout (apoE(-/-)/ iNOS(-/-)) mice to assess vascular NO, O2(-), and peroxynitrite formation by electron spin resonance spectroscopy, high performance liquid chromatography, and 3-nitrotyrosine staining. The relevance of the iNOS expressing cell compartment was tested by bone marrow transplantation. We show that iNOS significantly contributes to vascular NO production and itself produces O2(-), leading to peroxynitrite formation in atherosclerotic lesions. Our bone marrow transplantation experiments show that bone marrow derived cells exclusively mediate the proatherosclerotic effects of iNOS in males, while both parenchymal and bone marrow derived iNOS equally contribute to atherosclerosis in females. Moreover, iNOS expression affects vascular remodeling. These findings establish for the first time that the proatherosclerotic effects of iNOS vary with sex in addition to the compartment of its expression.

Effects of probiotic bacteria, isoflavones and simvastatin on lipid profile and atherosclerosis in cholesterol-fed rabbits: a randomized double-blind study

BackgroundMuch attention has been drawn to different alternative strategies for cardiovascular disease prevention. Objective: The aim of the present study was to observe and compare the effects of Enterococcus faecium CRL183 (probiotic microorganism), an isoflavones mixture and simvastatin (drug used to treat hypercholesterolemia) on lipid parameters and atherosclerosis development in rabbits with induced hypercholesterolemia.MethodsThe animals were randomly allocated to 5 experimental groups (n = 6) for 60 days: control (C) that did not consume cholesterol, hypercholesterolemic (H) that consumed an atherogenic diet (1.0% cholesterol wt/wt), hypercholesterolemic plus E. faecium (HE), hypercholesterolemic plus isoflavone (HI) and hypercholesterolemic plus simvastatin (HS). Total and HDL-cholesterol and triglycerides were determined by enzymatic methods; non-HDL-C was calculated by subtracting HDL-C from total cholesterol; and atherosclerosis was presented as the percentage of lesion area, relative to the total area from the aorta segment analyzed.ResultsSimvastatin significantly reduced the tot cholesterol (16%) and non-HDL-C level (17%) and increased the HDL-C (98%), compared to group H. E. faecium raised the HDL-C level by 43.3% (P < 0.05). Isoflavone decreased the total cholesterol and non-HDL-C concentrations (9%), but this effect was not statistically significant. At the end of the treatments, groups HE and HS had significantly lower levels of triglycerides in relation to H and HI. The atherosclerotic lesion area in the aortic arch was not different between groups. The extent of atherosclerosis in the thoracic and abdominal aorta was reduced in the groups HI and HS by 22.7% and 26.7% respectively, but this effect was not significant (P > 0.05).ConclusionThe results indicated that probiotic microorganism E. faecium CRL 183 could be used to improve the lipid profile as an alternative or an adjuvant for drug therapy. The effectiveness of simvastatin in the management of blood lipid was confirmed. There were no effects of soy isoflavones, E. faecium and simvastatin on atherosclerosis development.

Abstract 621: Attenuated Expression of Profilin-1 Confers Protection from Atherosclerosis in the LDL Receptor-null Mouse

INTRODUCTION. Atherosclerosis-related events are a major cause of morbidity and death worldwide. The mechanisms underlying atherogenesis are not fully understood. We showed in previous studies that the actin-binding protein profilin-1 (pfn) was upregulated in atheroscle-rotic lesions and in endothelial cells (EC) treated with oxidized LDL (oxLDL). HYPOTHESIS. In the present study, we tested the hypothesis that pfn levels play a role in early atheroma formation. RESULTS. Since Pfn −/− mice die during embryonic development, we tested the role of pfn in atherogenesis by crossing adult Pfn +/− mice, which are viable and display a ∼50% reduction in pfn levels, into the Ldlr −/− mouse model of atherosclerosis. Atherosclerotic lesion burden was assessed in Pfn +/−Ldlr −/− (PfnHet) and Ldlr −/−control mice (PfnWT) fed an atherogenic high-cholesterol diet (HCD) for two months. Both males and females PfnHet exhibited a significant reduction in the percent lesion area in the descending aorta, when compared to PfnWT (females: 1.1 Â 27&gt; 0.1 vs PfnWT 4.17 Â27&gt; 0.49%, n=10; males: 1.34 Â 27&gt; 0.22 vs PfnWT 3.4 Â 27&gt; 0.36%, n=6). Similarly, aortic arch lesions were reduced in PfnHet (0.08 Â 27&gt; 0.3 vs PfnWT 0.20 Â 27&gt; 0.05 mm2, n=10). Total cholesterol and triglyceride levels were comparable in the two groups. Relevant atheroprotective changes were identified in PfnHet. When compared to PfnWT, aortas from PfnHet mice showed preserved eNOS activation, NO production and NO-dependent signaling. These changes were observed under HCD but not under a normal diet, thus indicating that pfn levels modified the response of the endothelium to atherogenic injury rather than its basal function. Similarly, knockdown of pfn in cultured aortic EC was protective against endothelial dysfunction triggered by oxLDL. Also, bone marrow-derived macrophages from PfnHet showed reduced internalization of oxLDL and oxLDL-induced inflammatory pathways, including activation of p38. CONCLUSIONS. These studies demonstrate that pfn levels modulate critical processes for atherosclerotic lesion formation through combined endothelial- and macrophage-dependent mechanisms.

Gastric mucosal injury due to hemorrhagic reperfusion and efficacy ofSalvia miltiorrhizaeextract F and cimetidine

To observe the gastric mucosal injury caused by hemorrhagic shock and reperfusion and to compare the effect between Salvia miltiorrhizae extract F (SEF) and cimetidine (CI) on it. A model of hemorrhage/reperfusion injury was produced by Itoh method. Wistar rats were randomly divided into three groups: 0.9% sodium chloride treatment group (NS group), SEF treatment group (SEF group), and CI treatment group (CI group). Saline, SEF and CI were injected respectively. The index of gastric mucosal lesions (IGML) was expressed as the percentage of lesion area in the gastric mucosa. The degree of gastric mucosal lesions was categorized into grades 0, 1, 2, 3. Atom absorption method was used to measure the intracellular calcium content. Radioimmunoassay was used to measure the concentrations of prostaglandins. IGML (%) and grade 3 (%) were 23.18+/-6.82, 58.44+/-9.07 in NS group, 4.42+/-1.39, 20.32+/-6.95 in SEF group and 3.74+/-1.56, 23.12+/-5.09 in CI group, and the above parameters in SEF group and CI group decreased significantly (IGML: SEF vs NS, t = 6.712, P = 0.000<0.01; CI vs NS, t = 6.943, P = 0.000<0.01; grade 3: SEF vs NS, t = 8.386, P = 0.000; CI vs NS, t = 8.411, P = 0.000), but the grade 0 and grade 1 damage in SEF group (22.05+/-5.96, 34.12+/-8.12) and CI group (18.54+/-4.82, 30.15+/-7.12) were markedly higher than those in NS group (3.01+/-1.01, 8.35+/-1.95; grade 0: SEF vs NS, t = 8.434, P = 0.000<0.01; CI vs NS, t = 7.950, P = 0.000<0.01; grade 1: SEF vs NS, t = 8.422, P = 0.000<0.01; CI vs NS, t = 8.448, P = 0.000<0.01). The intracellular calcium content (microg/mg) in SEF group (0.104+/-0.015) and CI group (0.102+/-0.010) was markedly lower than that in NS group (0.131+/-0.019, SEF vs NS, t = 2.463, P = 0.038<0.05; CI vs NS, t = 3.056, P = 0.017<0.05). The levels (pg/mg) of PGE(2), 6-keto-PGF(1alpha) and 6-keto-PGF(1alpha)/TXB(2) were 540+/-183, 714+/-124, 17.38+/-5.93 in NS group and 581+/-168, 737+/-102, 19.04+/-8.03 in CI group, 760+/-192, 1 248+/-158, 33.42+/-9.24 in SEF group, and the above parameters in SEF group markedly raised (PGE(2): SEF vs NS, t = 2.282, P = 0.046<0.05; SEF vs CI, t = 2.265, P = 0.047<0.05; 6-keto-PGF(1alpha): SEF vs NS, t = 6.583, P = 0.000<0.000; SEF vs CI, t = 6.708, P = 0.000<0.01; 6-keto-PGF(1alpha)/TXB(2): SEF vs NS, t = 3.963, P = 0.003<0.001; SEF vs CI, t = 3.243, P = 0.009<0.01), whereas TXB(2) level in SEF group (45.37+/-7.54) was obviously lower than that in NS group (58.28+/-6.74, t = 3.086, P = 0.014<0.05) and CI group (54.32+/-6.89, t = 2.265, P = 0.047<0.05). No significant difference was shown between NS group and CI group (PGE(2): t = 0.414, P = 0.688>0.05; 6-keto-PGF(1alpha): t = 0.310, P = 0.763>0.05; TXB(2): t = 1.099, P = 0.298>0.05; 6-keto-PGF(1alpha)/TXB(2): t = 0.372, P = 0.718>0.05). Both SEF and CI could inhibit reperfusion-induced injury in gastric mucosa, but with different mechanisms. SEF could not only enhance the protective effect of gastric mucosa, but also abate the injury factors, while CI can only abate the injury factors.

Resistance to neointimal hyperplasia and fatty streak formation in mice with adrenomedullin overexpression.

Several in vitro studies have implicated that adrenomedullin (AM) plays an important role in the pathogenesis of vascular injury and fatty streak formation. To test this possibility in vivo, we evaluated 2 experimental models using transgenic mice overexpressing AM in a vessel-selective manner (AMTg mice). Placement of a periarterial cuff on femoral arteries resulted in neointimal formation at 2 to 4 weeks to a lesser extent in AMTg mice than in their wild-type littermates (at 28 days, intima/media area ratio 0.45+/-0.14 versus 1.31+/-0.41, respectively; P<0.001). This vasculoprotective effect observed in AMTg mice was inhibited by N(omega)-nitro-L-arginine methyl ester. We further examined the effect of AM on hypercholesterolemia-induced fatty streak formation by crossing AMTg mice with apolipoprotein E knockout mice (ApoEKO mice). The extent of the formation of fatty streak lesions was significantly less in ApoEKO/AMTg mice than in ApoEKO mice (percent lesion area 12.0+/-3.9% versus 15.8+/-2.8%, respectively; P<0.05). Moreover, endothelium-dependent vasodilatation as indicative of NO production was superior in AMTg/ApoEKO mice compared with ApoEKO mice. Taken together, our data demonstrated that AM possesses a vasculoprotective effect in vivo, which is at least partially mediated by NO.

Dystrophin-deficient myocardium is vulnerable to pressure overload in vivo.

Dystrophin provides mechanical reinforcement to the membranes of myocytes. Dystrophin abnormalities are known to cause cardiomyopathy and skeletal muscle disorders; however, the pathogenesis of these abnormalities remains unclear. Dystrophin-deficient skeletal muscle is vulnerable to stresses such as stretch and hypo-osmotic shock. We investigated whether the myocardium of dystrophin-deficient (mdx) mice shows increased vulnerability to acute pressure overload in vivo. Abdominal aortic banding was performed in 12-week-old mdx and control mice. The aortic pressure was measured by cannulation of the right carotid artery at the time of sacrifice. Systolic pressures in mdx mice at 0, 1, 2, 7 and 14 days after aortic banding were 100 +/- 11, 119 +/- 7, 123 +/- 4, 134 +/- 11 and 130 +/- 10 mmHg, respectively. Microscopic analysis revealed focal lesions in the left ventricular wall in banded mdx mice. These lesions consisted of damaged myocytes and inflammatory cells, and also of fibrosis at a late stage. Similar lesions were not observed in non-banded or banded control mice. The proportion of areas of lesions to total left ventricular area increased over time: 1.0 +/- 0.6% in mdx mice without aortic banding (sham, n = 6), and 1.7+/-1.4% 1 day (n = 6, vs. sham, NS), 2.6 +/- 1.9% 2 days (n = 7, vs. sham, P < 0.05), 6.3+ /- 6.5% 7 days (n = 13, vs. sham, P < 0.05) and 9.9 +/- 8.3% 14 days after aortic banding (n=15, vs. sham, P < 0.01). Furthermore, linear regression analysis revealed a significant correlation between percentage of lesion area and systolic pressure in mdx mice (P < 0.05). Dystrophin-deficient myocardium is more vulnerable than normal myocardium to pressure overload in vivo. This result has two clinical implications: (1) the patients with dystrophynopathy, such as the Duchenne and the Becker types of muscular dystrophy and X-linked type of dilated cardiomyopathy, who develop arterial hypertension should be treated aggressively, and (2) they should avoid stresses that elevate blood pressure.

Expression of interleukin-6 in atherosclerotic lesions of male ApoE-knockout mice: inhibition by 17beta-estradiol.

Increased levels of interleukin-6 (IL-6) have been proposed to contribute to a number of pathological disorders, including osteoporosis and Alzheimer's disease. In human atherosclerotic lesions, IL-6 protein and mRNA have been detected, although the role of IL-6 in plaque formation is unknown. We have examined the expression pattern of IL-6 mRNA and secreted protein in male apolipoprotein E-knockout (apoE-KO) mice aortas. Furthermore, we have evaluated the effects of 17beta-estradiol (E2), a vasculoprotective sex steroid hormone, on the secretion of this inflammatory cytokine from isolated male apoE-KO mice aortas. The expression of IL-6 mRNA was detected by reverse transcription-polymerase chain reaction in the apoE-KO mouse aortas but not in the aortas of age-matched control mice. Similarly, the secretion of IL-6 protein from isolated apoE-KO aortic segments was significantly greater than that from aortas of age-matched control animals. The secretion of IL-6 from isolated aortic rings of apoE-KO mice ranging in age from 6 to 48 weeks showed a significant, positive correlation with percent lesion area measured in the same tissue. Immunohistochemical staining of apoE-KO mouse aortic tissue sections demonstrated colocalization of IL-6 expression with macrophages. Treatment of male apoE-KO mice with E2 for 3 weeks resulted in a statistically significant 50% reduction in IL-6 secretion from ex vivo aortic tissue segments. There was no significant change in total serum cholesterol and triglyceride levels in the E2-treated group compared with placebo-treated controls. These data demonstrate that (1) IL-6 mRNA and protein are expressed in the atherosclerotic plaques of apoE-KO mice aortas and (2) IL-6 production is suppressed by E2 treatment, which may contribute to the antiatherosclerotic effects of E2 in the apoE-KO mouse model of atherosclerosis.

Low density lipoprotein receptor-negative mice expressing human apolipoprotein B-100 develop complex atherosclerotic lesions on a chow diet: no accentuation by apolipoprotein(a).

We have generated mice with markedly elevated plasma levels of human low density lipoprotein (LDL) and reduced plasma levels of high density lipoprotein. These mice have no functional LDL receptors [LDLR-/-] and express a human apolipoprotein B-100 (apoB) transgene [Tg(apoB+/+)] with or without an apo(a) transgene [Tg(apoa+/-)]. Twenty animals (10 males and 10 females) of each of the following four genotypes were maintained on a chow diet: (i) LDLR-/-, (ii) LDLR-/-;Tg(apoa+/-), (iii) LDLR-/-;Tg(apoB+/+), and (iv)LDLR-/-;Tg(apoB+/+);Tg(apo+/-). The mice were killed at 6 mo, and the percent area of the aortic intimal surface that stained positive for neutral lipid was quantified. Mean percent areas of lipid staining were not significantly different between the LDLR-/- and LDLR-/-;Tg(apoa+/-) mice (1.0 +/- 0.2% vs. 1.4 +/- 0.3%). However, the LDLR-/-;Tg(apoB+/+) mice had approximately 15-fold greater mean lesion area than the LDLR-/- mice. No significant difference was found in percent lesion area in the LDLR-/-;Tg(apoB+/+) mice whether or not they expressed apo(a) [18.5 +/- 2.5%, without lipoprotein(a), Lp(a), vs. 16.0 +/- 1.7%, with Lp(a)]. Histochemical analyses of the sections from the proximal aorta of LDLR-/-;Tg(apoB+/+) mice revealed large, complex, lipid-laden atherosclerotic lesions that stained intensely with human apoB-100 antibodies. In mice expressing Lp(a), large amounts of apo(a) protein colocalized with apoB-100 in the lesions. We conclude that LDLR-/-; Tg(apoB+/+) mice exhibit accelerated atherosclerosis on a chow diet and thus provide an excellent animal model in which to study atherosclerosis. We found no evidence that apo(a) increased atherosclerosis in this animal model.

Interaction of Colletotrichum orbiculare with thrips and aphid feeding on watermelon seedlings

Watermelon ( Citrullus lanatus (Thunb.) Matsum. & Nakai) seedlings were either untreated or treated as follows: inoculated only with the fungus Colletotrichum orbiculare (Berk. & Mont.) Arx, infested only with thrips ( Thrips tabaci Lindeman) or aphids ( Aphis gossypii Glover), or infested with either insect before or after inoculation with C. orbiculare in a greenhouse. Plant heights, dry weights, and percent lesion area on cotyledons, true leaves, and the whole plant (cotyledons and leaves) were determined. When thrips were the challenge insects infested plants were among the shortest, but also the heaviest. Percent lesion area on cotyledons, leaves, and the whole plant was significantly reduced ( P ≤ 0.05) on plants infested with thrips before inoculation with C. orbiculare compared with plants receiving only C. orbiculare and plants infested after inoculation with C. orbiculare. With aphids as the challenge insect plant heights and dry weights were not affected by treatment. Percent lesion area on plants infested with aphids before, or after, inoculation with C. orbiculare was significantly lower than on plants inoculated with C. orbiculare only.

Health effects of acid aerosols formed by atmospheric mixtures.

Under ambient conditions, sulfur and nitrogen oxides can react with photochemical products and airborne particles to form acidic vapors and aerosols. Inhalation toxicological studies were conducted, exposing laboratory animals, at rest and during exercise, to multicomponent atmospheric mixtures under conditions favorable to the formation of acidic reaction products. Effects of acid and ozone mixtures on early and late clearance of insoluble radioactive particles in the lungs of rats appeared to be dominated by the oxidant component (i.e., the mixture did cause effects that were significantly different from those of ozone alone). Histopathological evaluations showed that sulfuric acid particles alone did not cause inflammatory responses in centriacinar units of rat lung parenchyma (expressed in terms of percent lesion area) but did cause significant damage (cell killing followed by a wave of cell replication) in nasal respiratory epithelium, as measured by uptake of tritiated thymidine in the DNA of replicating cells. Mixtures of ozone and nitrogen dioxide, which form nitric acid, caused significant inflammatory responses in lung parenchyma (in excess of effects seen in rats exposed to ozone alone), but did not damage nasal epithelium. Mixtures containing acidic sulfate particles, ozone, and nitrogen dioxide damaged both lung parenchyma and nasal epithelia. In rats exposed at rest, the response of the lung appeared to be dominated by the oxidant gas-phase components, while responses in the nose were dominated by the acidic particles. In rats exposed at exercise, however, mixtures of ozone and sulfuric acid particles significantly (2.5-fold) elevated the degree of lung lesion formation over that seen in rats exposed to ozone alone under an identical exercise protocol.