Microcalcifications in atherosclerotic lesion of apolipoprotein E‐deficient mouse

Evidence is accumulating that calcium-rich microdeposits in the vascular wall might play a crucial role in the onset and progression of atherosclerosis. Here we investigated an atherosclerotic lesion of the carotid artery in an established murine model, i.e. the apolipoprotein E-deficient (APOE^−/−) mouse to identify (i) the presence of microcalcifications, if any, (ii) the elemental composition of microcalcifications with special reference to calcium/phosphorus mass ratio and (iii) co-localization of increased concentrations of iron and zinc with microcalcifications. Atherosclerosis was induced by a flow-divider placed around the carotid artery resulting in low and high shear-stress regions. Element composition was assessed with a proton microprobe. Microcalcifications, predominantly present in the thickened intima of the low shear-stress region, were surrounded by areas with normal calcium levels, indicating that calcium-precipitation is a local event. The diameter of intimal microcalcifications varied from 6 to 70 μm. Calcium/phosphorus ratios of microcalcifications varied from 0.3 to 4.8, mainly corresponding to the ratio of amorphous calcium-phosphate. Increased iron and zinc concentrations commonly co-localized with microcalcifications. Our findings indicate that the atherosclerotic process in the murine carotid artery is associated with locally accumulated calcium, iron and zinc. The calcium-rich deposits resemble amorphous calcium phosphate rather than pure hydroxyapatite. We propose that the APOE^−/− mouse, in which atherosclerosis was evoked by a flow-divider, offers a useful model to investigate the pathophysiological significance of accumulation of elements such as calcium, iron and zinc.     

PKCη deficiency improves lipid metabolism and atherosclerosis in apolipoprotein E‐deficient mice

Genomewide association studies have shown that a nonsynonymous single nucleotide polymorphism in PRKCH is associated with cerebral infarction and atherosclerosis‐related complications. We examined the role of PKCη in lipid metabolism and atherosclerosis using apolipoprotein E‐deficient (Apoe^?/?) mice. PKCη expression was augmented in the aortas of mice with atherosclerosis and exclusively detected in MOMA2‐positive macrophages within atherosclerotic lesions. Prkch^+/+Apoe^?/? and Prkch^?/?Apoe^?/? mice were fed a high‐fat diet (HFD), and the dyslipidemia observed in Prkch^+/+Apoe^?/? mice was improved in Prkch^?/?Apoe^?/? mice, with a particular reduction in serum LDL cholesterol and phospholipids. Liver steatosis, which developed in Prkch^+/+Apoe^?/? mice, was improved in Prkch^?/?Apoe^?/? mice, but glucose tolerance, adipose tissue and body weight, and blood pressure were unchanged. Consistent with improvements in LDL cholesterol, atherosclerotic lesions were decreased in HFD‐fed Prkch^?/?Apoe^?/? mice. Immunoreactivity against 3‐nitrotyrosine in atherosclerotic lesions was dramatically decreased in Prkch^?/?Apoe^?/? mice, accompanied by decreased necrosis and apoptosis in the lesions. ARG2 mRNA and protein levels were significantly increased in Prkch^?/?Apoe^?/? macrophages. These data show that PKCη deficiency improves dyslipidemia and reduces susceptibility to atherosclerosis in Apoe^?/? mice, showing that PKCη plays a role in atherosclerosis development.     

Dystrophin expression improves myofiber survival in mdx muscle following intramuscular plasmid DNA injection

Expression of Becker-like and full-length human dystrophlnswas stable for at least 6 months In mdx mouse muscle followingIntramuscular plasmid DNA Injection. Intramuscular Injectionof a single plasmld DNA encoding both luciferase and dystrophlnresulted In stable luclferase expression for at least 2 monthsin mdx muscle, whereas Injection of plasmld DNA encoding onlyluclferase did not result In stable luclferase expression. Theseresults suggest that expression of either full-length or Becker-likedystrophlns protects mdx mouse myoflbers from degeneration.     

Resolution of defective dorsal aortae patterning in Sema3E‐deficient mice occurs via angiogenic remodeling

Background: Neuronal guidance cues influence endothelial cell (EC) behavior to shape the embryonic vascular system. The repulsive neuronal guidance cue, Semaphorin 3E (Sema3E), is critical for creating avascular zones that instruct and subsequently pattern the first embryonic vessels, the paired dorsal aortae (DA). Sema3E^?/? embryos develop highly branched plexus‐like vessels during vasculogenesis, instead of smooth paired vessels. Unexpectedly, despite these severe DA patterning defects, mutant mice are viable throughout adulthood. Results: Examination of Sema3E^?/? mice reveals that the plexus‐like DA resolve into single, unbranched vessels between embryonic day (E) E8.25 and E8.75. Although fusion of Sema3E^?/? DA occurs slightly earlier than in heterozygotes, the DA are otherwise indistinguishable, suggesting a complete “rescue” in their development. Resolution of the DA null plexuses occurs by remodeling rather than by means of changes in cell proliferation or death. Conclusions: Normalization of Sema3E^?/? DA patterning defects demonstrates resilience of embryonic vascular patterning programs. Additional repulsive guidance cues within the lateral plate mesoderm likely re‐establish avascular zones lost in Sema3E^?/? embryos and guide resolution of mutant plexus into branchless, parallel aortae. Our observations explain how Sema3E^?/? mice survive throughout development and into adulthood, despite severe initial vascular defects. Developmental Dynamics 242:570–580, 2013. © 2013 Wiley Periodicals, Inc.     

Postnatal proliferation of DRG non‐neuronal cells in vitamin E‐deficient rats

Changes in the number of satellite cells in neuron body sheaths in dorsal root ganglia (DRGs) were studied from 1 to 5 months of age in control and in vitamin E‐deficient rats; furthermore, the satellite cell proliferation rate was detected in the same groups of animals with immunohistochemistry for 5‐bromo‐2′‐deoxyuridine (BrdU). The number of satellite cells in sheaths of DRG neurons increased in the period of life considered both in control and in vitamin E‐deficient rats. Satellite cell proliferation was observed in both groups, but its rate was found to be higher in vitamin E‐deficient rats. The results obtained in control rats confirm that mitotic ability is retained by satellite cells in adulthood and show that at least some of newborn satellite cells add to the pre‐existing population. The results obtained in vitamin E‐deficient rats suggest that a faster turnover in satellite cell population takes place in these animals and support the idea that vitamin E could be an exogenous factor controlling cell proliferation. Anat Rec 256:109–115, 1999. © 1999 Wiley‐Liss, Inc.     

Cardiovascular functional phenotypes and pharmacological responses in apolipoprotein E deficient mice

This is an overview of recent findings, mainly from our laboratory, describing the cardiovascular functional phenotypes and pharmacological responses in mice genetically deficient in apolipoprotein E (apoE-KO). ApoE-KO mice are hyperlipidemic and spontaneously develop atherosclerosis. We have detected several new cardiovascular functional phenotypes in apoE-KO mice: hyperglycemia, age-dependent aortic stiffening, cardiac hypertrophy and increased cardiac output. Angiotensin II (Ang II) promoted vascular inflammation and atherosclerosis, increased vascular stiffness, and induced abdominal aortic aneurysm (AAA) in apoE-KO mice, in which activation of NF-kappaB mediated pro-inflammatory genes plays an important role. Inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME) significantly inhibited NO-mediated vascular responses and accelerated atherosclerosis in apoE-KO mice, supporting a protective role of NO against atherosclerosis. Estrogen attenuated atherosclerosis in apoE-KO mice, even in those with atherosclerosis being accelerated by Ang II, hyperglycemia, or L-NAME, demonstrating an anti-atherosclerotic effect of estrogen. Simvastatin paradoxically increased lipid and atherosclerosis in apoE-KO mice, but it decreased lipid and atherosclerosis in LDLR-KO mice, indicating that anti-atherosclerotic effect of simvastatin requires the presence of an intact apoE.     

Ovarian morphometrics in TP53‐deficient mice

The objective of these investigations was to characterize ovarian responses to hormonal stimulation in TP53‐deficient mice. TP53‐deficient (KO) and wild‐type (WT) mice were induced to ovulate with pregnant mare serum gonadotropin followed by human chorionic gonadotropin. Effect of estradiol on ovarian morphology was determined in induced and control mice implanted with estradiol‐containing or placebo pellets. Blood was collected and mice were killed 7 days following implantation. Preserved ovaries were serially sectioned and stained. Numbers of follicles (all classifications) decreased with ovulation induction, but did not differ between WT and KO mice. Numbers of corpora lutea (CL) were less in ovulation‐induced KO mice treated with estradiol compared to WT mice. Area of individual CL and serum concentrations of progesterone were greater in ovulation‐induced KO mice given estradiol compared to WT mice. Ovulation‐induced KO mice had more, larger hemorrhagic follicles than similarly treated WT mice, but hemorrhagic follicles were not influenced by estradiol. Proliferation of ovarian surface epithelial cells did not differ between KO and WT mice induced to ovulate and given estradiol. Ovaries from TP53 gene knockout mice (n = 4) induced to ovulate and given a 21‐day estradiol implant three times over 58 days were observed for precursor lesions. There was no indication of precursor lesions in any TP53 KO or WT mouse. TP53 status did not influence recruitment of follicles, but TP53 deficiency hindered the ability of human chorionic gonadotropin to cause ovulation. Anat Rec, 290:59–64, 2007. © 2006 Wiley‐Liss, Inc.     

丙型肝炎病毒核心基因疫苗诱导小鼠细胞及体液免疫应答

为了探索丙型肝炎病毒核心区基因疫苗对小白鼠细胞及体液免疫功能的影响。本文将ＨＣＶ核心区基因定向克隆于质粒ｐｃＤＮＡ３巨细胞病毒启动子下游,构建了能在真核细胞内表达的重组基因疫苗ｐｃＤＮＡ３－ＨＣＶ,将此疫苗通过多点肌肉注射免疫ＢＡＬＢ／Ｃ小鼠。结果发现接种了该疫苗的小鼠出现抗－ＨＣＶＩｇＧ阳性,其抗体水平明显高于对照组,同时Ｔｈ１免疫应答相关的细胞因子ＩＬ－２及γ干扰素水平也明显高于对照组,其结果     

Regional difference of lipid distribution in brain of apolipoprotein E deficient mice

According to recent knowledge, apolipoprotein E (apo E) plays a significant role in the homeostasis of intracellular cholesterol level in various tissues. Apo E deficient mice develop hyperlipidemia, and suffer from atherosclerosis in extracerebral blood vessels and neurodegeneration in the central nervous system. Furthermore, Walker et al. (Am. J. Path., 1997;151:1371–1377) demonstrated cerebral xanthomas of various sizes in the brain of apo E deficient mice. In the present study, it is illustrated that in the homozygous apo E deficient mice of advancing age, a great number of foamy macrophages extravasate from microvessels in thalamus and fimbria hippocampi, and scatter in the perivascular regions and migrate toward the ependyma, fimbria hippocampi, hippocampus, and thalamus. Here, it must be pointed out that under hyperlipidemia, although foamy macrophages made clusters in the perivascular region, the cerebral microvessels did not develop atherosclerosis. On the other hand, in the other cerebral regions such as cerebral cortex, caudoputamen, globus pallidus, and substantia nigra, macrophages did not appear and microvessels retained normal shapes, but the fluorescent granular perithelial (in short, FGP) cells accompanied by these vessels contained a certain amount of lipids. That is, in the cerebral cortex and caudoputamen, lipid components are detected in FGP cells and microglia, while in the globus pallidus and substantia nigra, they are mainly localized in astrocytes. The reason why the astrocytes in such defined regions contain, specifically, a high quantity of lipid components remains unsettled. Axonal degenerations are often represented in thalamus, globus pallidus, and substantia nigra. On the other hand, in the specimens of Wild‐type mice, lipid components were observed only in FGP cells, and the vascular architecture took a normal profile. Any lipid laden macrophages and the axonal degenerations could not be detected through the cerebral parenchyma. Furthermore, it is also a noticeable finding that immunohistochemically, the FGP cells express a positive reaction against the antibody of apo E in the Wild‐type mice, but those of homozygous apo E deficient mice are immunonegative. FGP cells are not only provided with the scavenger receptor, but also contribute to the lipid metabolism in the brain. Anat Rec 256:165–176, 1999. © 1999 Wiley‐Liss, Inc.     

Curcumin alleviates immune‐complex‐mediated glomerulonephritis in factor‐H‐deficient mice

Complement factor H (Cfh) is a key regulator of the complement cascade and protects C57BL/6 mice from immune complex-mediated complement-dependent glomerulonephritis. In chronic serum sickness (CSS) there are increased deposits of immune complexes in the glomeruli with inflammation and a scarring phenotype. As cucurmin is an effective anti-inflammatory agent and reduces complement activation, we hypothesized that it should alleviate renal disease in this setting. To determine the effectiveness of curcumin, an apoferritin-induced CSS model in Cfh-deficient (Cfh^−/−) mice was used. Curcumin treatment (30 mg/kg) given every day in parallel with apoferritin reduced glomerulonephritis and enhanced kidney function (blood urea nitrogen, 45·4 ± 7·5 versus 35·6 ± 5·1; albuminuria, 50·1 ± 7·1 versus 15·7 ± 7·1; glomerulonephritis, 2·62 + 0·25 versus 2 + 0·3, P < 0·05). In line with reduced IgG deposits in mice with CSS given curcumin, C9 deposits were reduced indicating reduced complement activation. Mice treated with curcumin had a significant reduction in the number of splenic CD19⁺ B cells and the ratio of CD19 : CD3 cells (P < 0·05) with no change in the T-cell population. Myeloperoxidase assay showed reduced macrophages in the kidney. However, a significant reduction in the M2 subset of splenic macrophages by apoferritin was prevented by curcumin, suggesting a protective function. Curcumin treatment reduced mRNA expression of inflammatory proteins monocyte chemoattractant protein-1 and transforming growth factor-β and matrix proteins, fibronectin, laminin and collagen. Our results clearly illustrate that curcumin reduces glomerulosclerosis, improves kidney function and could serve as a therapeutic agent during serum sickness.     

Comparison of astrocytic and myocytic metabolic dysregulation in apolipoprotein E deficient and human apolipoprotein E transgenic mice

The accumulation of tubular aggregates in type II skeletal muscle fibres and fibrillo-granular inclusions in hippocampal protoplasmic astrocytes are characteristic lesions of apolipoprotein E deficient mice. Moreover these inclusions reacted immunocytochemically with an antibody specific to fragment 17-24 of the published sequence of Alzheimer's amyloid peptide. In an effort to evaluate the role of apolipoprotein E in the formation of these abnormal structures, we examined the tibialis anterior muscle and the hippocampus of several groups of animals including: (i) apolipoprotein E "knockout" mice which had been whole body irradiated with 1200 rads and bone marrow replenished with apolipoprotein E sufficient marrow; and (ii) three transgenic murine strains that had been genetically engineered to express either human apolipoprotein E2, E3 or E4 protein on an apoE deficient background. The results of this study showed that the presence of murine apolipoprotein E (even in subnormal levels in the serum) in irradiated bone marrow replenished mice and in all three (E2, E3 or E4) human apoE transgenic strains was sufficient to prevent the aggregation of sarcoplasmic tubules in the tibialis anterior type II muscle fibres. Similarly apolipoprotein E "knockout" bone marrow replenished mice and all three transgenic strains expressing the different human apolipoprotein E alleles reduced the number of the astrocytic inclusions in the hippocampus to levels not significantly different to those observed in control C57Bl6J animals.The data obtained in this study indicate that neurological and neuromuscular abnormalities found in apoE deficient mice are reversed when apoE protein is replaced in the circulation, either by bone marrow transplantation of normal apoE sufficient marrow, or by gene therapy with the apoE gene, albeit of human origin and irrespective of the allele used.     

Intramuscular injection of a plasmid vector expressing human apolipoprotein E limits progression of xanthoma and aortic atheroma in apoE-deficient mice

Apolipoprotein-E (apoE) protects against coronary artery disease via hepatic removal of atherogenic remnant lipoproteins, sequestration of cholesterol from vessel walls and local anti-oxidant, anti-platelet and anti-inflammatory actions. ApoE gene transfer may thus ameliorate a hyperlipidaemic profile and have beneficial effects at lesion sites to prevent or regress atherosclerosis, a concept endorsed by adenoviral-mediated hepatic expression studies. Here, using plasmid vectors expressing allelic human apoE2 or apoE3 isoforms, skeletal muscle was evaluated as an effective secretory platform for apoE gene augmentation. Transfected myoblasts and myotubes were found to efficiently secrete recombinant apoE in vitro as spherical 10-16 nm lipoprotein particles with pre-beta mobility. Intramuscular plasmid injection in apoE(-/-) mice, which develop spontaneous atherosclerotic plaque and xanthoma resulted in expression and secretion of apoE. Human apoE mRNA was detected by RT-PCR in injected muscles and, although concentrations of apoE3, which is rapidly cleared from plasma, were near ELISA detection limits, levels of plasma apoE2 were measurable (17.5 +/- 4.3 ng/ml). To assess whether muscle-based expression of apoE2 could inhibit atherogenesis, long-term follow-up studies were conducted. Although hyperlipidaemia was not reduced in treated animals, end-point pathology showed clear retardation of atherosclerotic and xanthomatous lesions. Up to 9 months following a single apoE2 plasmid administration, atherosclerotic lesion coverage in proximal aorta was significantly reduced by 20-30% (P < 0.01), whereas development of gross dorsal xanthoma (>5 mm diameter) was effectively reduced to zero. We conclude that expression of apoE from ectopic muscle sites has therapeutic potential to limit progression of atherosclerosis.     

Sleep and cardiovascular phenotype in middle‐aged hypocretin‐deficient narcoleptic mice

Narcolepsy with cataplexy (NC) is a lifelong disorder caused by loss of hypothalamic hypocretin/orexin (HCRT) neurones, often starting in childhood. NC patients show altered control of heart rate (HR) and a normotensive non‐dipper blood pressure (BP) profile, but the natural history and prognostic significance of these alterations remain unclear. Similar alterations have been observed in HCRT‐ataxin‐3 transgenic (TG) NC mice lacking HCRT neurones, but studies have been limited to young adult individuals <4 months of age. Here we evaluated long‐term effects of NC on derangements in the wake–sleep state and cardiovascular control by studying middle‐aged TG. We chronically instrumented TG and wild‐type mice aged 10–11 months with electrodes for sleep scoring and a telemetric transducer for BP and HR measurements. We then recorded mice in freely behaving conditions. TG showed a NC phenotype including fragmentation of wakefulness, reduced latency to rapid eye movement sleep (REMS) and cataplexy‐like events. TG also showed blunted BP decline on entering non‐rapid eye movement sleep (NREMS), enhanced BP increase on passing to REMS, increased HR, and blunted changes in HR upon arousal and awakening from NREMS. Histological and ultrastructural analysis of cardiovascular and renal tissue did not reveal evidence of subclinical hypertensive organ damage. These data indicate that HCRT neurone loss in TG causes alterations in wake–sleep behaviour and cardiovascular control that are not peculiar to the beginning of the disease but are maintained at least up to middle age. These alterations are similar to those in adult NC patients, but do not produce early subclinical damage to the heart and kidneys.     

电脉冲介导hIL-10基因转移治疗骨关节炎的实验研究

目的 研究电脉冲介导人白细胞介素10裸质粒肌肉注射对骨关节炎的治疗作用。方法 兔右膝关节髌旁内侧切口,行内侧半月板切除术制作骨关节炎模型,4周后按分组于右侧股四头肌注射pcDI或pcDI-IL10质粒,然后立即于注射部位施以电压200v(电极间距离为1cm),波宽40ms,脉冲次数6次和频率1Hz的电脉冲。共注射2次,每次间隔2周。按分组情况分别于术后4周、8周处死动物,行解剖显微镜观察及关节软骨、滑膜病理检查。结果 pcDI-IL10质粒注射组的关节软骨破坏程度较注射pcDI组轻(P<0.01),而较4周处死组稍重。结论 电脉冲介导肌肉pcDI-IL10转移可以延缓骨关节炎的发展。     

Epithelial‐microbial crosstalk in polymeric Ig receptor deficient mice

Innate and adaptive mucosal defense mechanisms ensure a homeostatic relationship with the large and complex mutualistic gut microbiota. Dimeric IgA and pentameric IgM are transported across the intestinal epithelium via the epithelial polymeric Ig receptor (pIgR) and provide a significant portion of the first line of natural or adaptive antibody‐mediated immune defense of the intestinal mucosa. We found that colonic epithelial cells from pIgR KO mice differentially expressed (more than twofold change) more than 200 genes compared with cells from WT mice, and upregulated the expression of antimicrobial peptides in a commensal‐dependent manner. Detailed profiling of microbial communities based on 16S rRNA genes revealed differences in the commensal microbiota between pIgR KO and WT mice. Furthermore, we found that pIgR KO mice showed increased susceptibility to dextran sulfate sodium‐induced colitis, and that this was driven by their conventional intestinal microbiota. Thus, in the absence of pIgR, the stability of the commensal microbiota is disturbed, gut homeostasis is compromised, and the outcome of colitis is significantly worsened.     

Regional difference of lipid distribution in brain of apolipoprotein E deficient mice.

According to recent knowledge, apolipoprotein E (apo E) plays a significant role in the homeostasis of intracellular cholesterol level in various tissues. Apo E deficient mice develop hyperlipidemia, and suffer from atherosclerosis in extracerebral blood vessels and neurodegeneration in the central nervous system. Furthermore, Walker et al. (Am. J. Path., 1997;151:1371-1377) demonstrated cerebral xanthomas of various sizes in the brain of apo E deficient mice. In the present study, it is illustrated that in the homozygous apo E deficient mice of advancing age, a great number of foamy macrophages extravasate from microvessels in thalamus and fimbria hippocampi, and scatter in the perivascular regions and migrate toward the ependyma, fimbria hippocampi, hippocampus, and thalamus. Here, it must be pointed out that under hyperlipidemia, although foamy macrophages made clusters in the perivascular region, the cerebral microvessels did not develop atherosclerosis. On the other hand, in the other cerebral regions such as cerebral cortex, caudoputamen, globus pallidus, and substantia nigra, macrophages did not appear and microvessels retained normal shapes, but the fluorescent granular perithelial (in short, FGP) cells accompanied by these vessels contained a certain amount of lipids. That is, in the cerebral cortex and caudoputamen, lipid components are detected in FGP cells and microglia, while in the globus pallidus and substantia nigra, they are mainly localized in astrocytes. The reason why the astrocytes in such defined regions contain, specifically, a high quantity of lipid components remains unsettled. Axonal degenerations are often represented in thalamus, globus pallidus, and substantia nigra. On the other hand, in the specimens of Wild-type mice, lipid components were observed only in FGP cells, and the vascular architecture took a normal profile. Any lipid laden macrophages and the axonal degenerations could not be detected through the cerebral parenchyma. Furthermore, it is also a noticeable finding that immunohistochemically, the FGP cells express a positive reaction against the antibody of apo E in the Wild-type mice, but those of homozygous apo E deficient mice are immunonegative. FGP cells are not only provided with the scavenger receptor, but also contribute to the lipid metabolism in the brain.     

3,4,5,6-四羟基(口山)酮抑制ApoE基因缺陷小鼠动脉粥样硬化形成及机制

目的：研究3,4,5,6-四羟基口山酮抑制ApoE基因缺陷小鼠动脉粥样硬化(AS)形成的机制及其与内源性一氧化氮合酶(NOS)抑制剂非对称性二甲基精氨酸(ADMA)的关系。方法：32只小鼠分为4组(n=8):正常对照组(C57BL/6J小鼠，等体积溶媒灌胃)；模型组(ApoE基因缺陷小鼠，等体积溶媒灌胃)；低剂量口山酮组［ApoE基因缺陷小鼠，口山酮10mg/（kg·d）灌胃］；高剂量口山酮组［ApoE基因缺陷小鼠，口山酮20mg/（kg·d）灌胃］；检测主动脉脂质斑块面积、血脂、红细胞变形性和血浆ADMA的水平。结果：与模型组比较，口山酮可以显著降低血浆ADMA水平和斑块面积，降低血浆总胆固醇(TC)、血浆总甘油三酯(TG)、血浆低密度胆固醇(LDL-C)，显著升高血浆高密度胆固醇(HDL-C)和改善红细胞变形性。结论：3,4,5,6-四羟基口山酮具有抗AS作用, 其作用机制与改善脂质代谢和降低血浆ADMA的水平有关。     

Blockade of endothelin receptors reduces diet-induced hypercholesterolemia and atherosclerosis in apolipoprotein E-deficient mice.

OBJECTIVE: Endothelin (ET)-1 has proatherogenic properties, since ET receptor antagonists reduce atherosclerotic lesions in animals. However, we recently demonstrated that ET-1 and ET(B) receptors are increased in atherosclerotic lesions. To further examine the effects of ET(B) receptor antagonism on atherogenesis, we investigated the chronic effects of the nonselective ET(A)/ET(B) receptor antagonist SB209670 on the development of atherosclerosis in apolipoprotein E (ApoE)-deficient mice. METHODS: Ninety-four male mice (10 weeks of age) were randomly divided into four groups: mice fed a Western-type diet or a chow diet with SB209670 treatment (10 mg/kg/day) or placebo for 12 weeks. RESULTS: In mice fed the Western-type diet, but not in mice fed the chow diet, treatment with SB209670 significantly attenuated the increase in plasma total cholesterol, predominantly in the very-low-density lipoprotein and intermediate-density lipoprotein fractions, without altering the plasma triglyceride level. Furthermore, treatment with SB209670 significantly reduced the extent of aortic atherosclerosis, by 53% in mice fed the Western-type diet and by 38% in mice fed the chow diet. Histological analysis revealed that SB209670 prevented the formation of atheromatous plaque lesions by inhibiting the fibroproliferative process. CONCLUSION: We found that chronic administration of SB209670 reduced diet-induced hypercholesterolemia and atherosclerosis in ApoE-deficient mice. Thus, nonselective ET receptor antagonists may have a therapeutic potential in the treatment of human atherosclerotic disease.