Circulating smooth muscle cell plasticity in the development of transplant arteriosclerosis

To date, chronic transplant dysfunction (CTD) is recognized as the major cause of long-term transplant loss (>1 year) after transplantation. CTD presents histologically with obliterated intragraft arteries as a result of intimal hyperplasia referred to as transplant arteriosclerosis (TA). Neointimal lesions predominantly consist of vascular smooth muscle cells (VSMCs) intermingled with some inflammatory cells. The pathogenesis of TA is believed to be multifactorial, and many risk factors have been identified. Because the precise pathogenetic mechanisms underlying TA are still largely unknown, adequate prevention and treatment protocols are not available. In this review, we discus the origin (donor vs recipient, bone marrow vs non-bone marrow) of neointimal endothelial cells (ECs) and VSMCs in TA lesions, which were formerly believed to be solely graft-derived. On the basis of the data obtained in both clinical and experimental transplantation, it appears that the process leading to TA is heterogeneous and that neointimal ECs and VSMCs can be recruited from different sources, possibly depending on the severity of vascular damage. These data suggest a significant role of host-derived circulating EC-VSMC progenitor cells, which may be partly bone marrow-derived. These circulating progenitor cells are potential targets for therapeutic intervention to ameliorate TA development or occlusive vascular disease in general.     

Contribution of aldose reductase to diabetic hyperproliferation of vascular smooth muscle cells

The objective of this study was to determine whether the polyol pathway enzyme aldose reductase mediates diabetes abnormalities in vascular smooth muscle cell (SMC) growth. Aldose reductase inhibitors (tolrestat or sorbinil) or antisense aldose reductase mRNA prevented hyperproliferation of cultured rat aortic SMCs induced by high glucose. Cell cycle progression in the presence of high glucose was blocked by tolrestat, which induced a G0-G1 phase growth arrest. In situ, diabetes increased SMC growth and intimal hyperplasia in balloon-injured carotid arteries of streptozotocin-treated rats, when examined 7 or 14 days after injury. Treatment with tolrestat (15 mg x kg(-1) x day(-1)) diminished intimal hyperplasia and decreased SMC content of the lesion by 25%. Although tolrestat treatment increased immunoreactivity of the lesion with antibodies raised against protein adducts of the lipid peroxidation product 4-hydroxy trans-2-nonenal, no compensatory increase in lesion fibrosis was observed. Collectively, these results suggest that inhibition of aldose reductase prevents glucose-induced stimulation of SMC growth in culture and in situ. Even though inhibition of aldose reductase increases vascular oxidative stress, this approach may be useful in preventing abnormal SMC growth in vessels of diabetic patients.     

Functions of vascular wall cells related to development of transplantation-associated coronary arteriosclerosis

The accelerated form of arteriosclerosis that occurs in the coronary circulation of transplanted hearts currently presents a major limitation to the long-term success of this therapy. The pathogenesis of this lesion is unclear. Recent advances in vessel wall biology have disclosed interplay between mediators of the immune response and functions of vascular cells of potential significance in the formation of this accelerated form of arterial disease. We hypothesize that the development of accelerated arteriosclerosis in the arteries of transplanted hearts represents a form of chronic immunologic reaction resembling delayed-type hypersensitivity localized in the graft's arteries, a manifestation of cellular immunity mediated in large part by a regionally acting cytokine network. We emphasize the active responses of intrinsic vessel wall cells, including inappropriate expression of HLA and the likely participation of cytokines derived from vascular cells as well as from infiltrating leukocytes in amplification and propagation of this localized chronic immune reaction. This mechanism, which involves helper T cells interacting with class II HLA, may distinguish transplantation-associated arteriosclerosis from typical acute rejection, which may involve primarily cytolytic T cells interacting with class I HLA. Lesions of the common variety of atherosclerosis manifest certain features of immune activation. Therefore, we further hypothesize that the transplantation-associated form represents an extreme case of processes that also contribute to usual coronary atherosclerosis. For this reason, study of the accelerated disease may aid understanding of atherogenesis in general. Unraveling the basic pathobiology of these clinically important arterial diseases should lay the groundwork for rational design of selective therapeutic strategies to prevent or retard their development.     

Recipient origin of neointimal vascular smooth muscle cells in cardiac allografts with transplant arteriosclerosis

BACKGROUND: Coronary artery disease is today's most important post-heart transplantation problem after the first perioperative year. Histologically, coronary artery disease is characterized by transplant arteriosclerosis. The current view on this vasculopathy is that vascular smooth muscle (VSM) cells from the media of affected arteries proliferate and migrate into the sub-endothelial space (intima) in response to signals from inflammatory cells and damaged graft endothelium. According to this model, the intimal VSM cells in transplant arteriosclerotic lesions should originate from donor tissue. Using recipient-specific polymerase chain reaction (PCR) analysis of microdissected, single, neointimal VSM nuclei, we recently showed that after allogeneic aorta transplantation the neointimal VSM cells are of recipient and not of donor origin. In this study, we analyzed whether VSM-cell replacement with recipient-derived cells also takes place after allogeneic heart transplantation. METHODS: Cardiac allografts, when transplanted from female donors to male immune-modulated recipient rats, eventually developed transplant arteriosclerosis. We microdissected alpha-actin positive neointimal VSM cells from tissue sections and determined the origin (donor or recipient) using recipient-specific (male), single-cell, PCR analysis. RESULTS: In total, we analyzed 35 VSM-cell nuclei from 3 allografts, and PCR analysis revealed that 30/35 (86%) of the samples displayed the male-specific 128 base pair DNA fragment. These results indicate that after allogeneic cardiac transplantation, at least 86% of VSM cells in transplant arteriosclerotic lesions are of recipient origin. CONCLUSIONS: In contrast to current thought, the neointimal VSM cells in cardiac allografts that show transplant arteriosclerosis are of recipient and not of donor origin.     

血管壁重塑与平滑肌细胞表型改变及调亡的研究

目的 研究血管平滑肌细胞(VSMC)表型改变和调亡与血管壁重塑的关系。方法 建立兔髂动脉粥样硬化再狭窄模型，分析再狭窄血管壁形态和结构变化，研究中膜、内膜VSMC的表型改变，检测各个时间段内膜和中膜层VSMC调亡。结果 再狭窄血管腔面积与血管壁重塑指数呈正相关(r＝0．9250，P＝0．0024)，再狭窄血管的管径较对侧明显缩小(P＝0．0001)。中膜VSMC表型主要以收缩型表型为主，血管壁内膜的VSMC的表型发生动态变化。中膜与内膜VSMC调亡峰值基本一致，中膜VSMC调亡指数明显高于内膜(P＝0．0061)。结论 血管壁重塑在血管重建再狭窄中起着重要的作用，在血管壁重塑过程中调控VSMC的表型转化和调亡可能控制血管壁的不适重塑，减少再狭窄的发生率。     

红景天苷对低氧环境下大鼠阴茎海绵体平滑肌细胞α-肌动蛋白和骨桥蛋白表达的影响

目的:探讨红景天苷对低氧SD大鼠阴茎海绵体平滑肌细胞(CCSMC)α-肌动蛋白、骨桥蛋白(OPN)表达的影响。方法:体外培养SD大鼠CCSMC,免疫组化法鉴定细胞;设正常对照组(21%O2浓度)、低氧组(1%O2浓度)、低氧+红景天苷1 mg/L组、低氧+红景天苷3 mg/L组、低氧+红景天苷5 mg/L组、低氧+前列腺素E1(PGE1)0.4μg/L组,分别培养48 h;RT-PCR法分别测定各组α-肌动蛋白、OPN的相对表达量。结果:体外培养的CCSMC生长良好,抗平滑肌α-肌动蛋白单克隆抗体免疫组化染色阳性;与正常对照组比较,低氧组细胞的α-肌动蛋白表达量下降、OPN表达量升高(P<0.01);与低氧组比较,红景天苷5 mg/L组α-肌动蛋白表达量升高、OPN表达量降低(P<0.01),与PGE1作用相当(P﹥0.05)。结论:低氧可引起SD大鼠CCSMC收缩型标志物α-肌动蛋白表达降低,合成型标志物OPN表达升高,推测低氧可能引起CCSMC由收缩型向合成型转化。红景天苷能抑制低氧引起的CCSMCα-肌动蛋白表达降低、OPN表达升高,浓度为5 mg/L时与PGE1作用几乎相当。     

Quantitative analysis of nitroglycerin-induced coronary artery vasodilation in transplanted hearts.

Quantitative serial coronary angiograms performed annually over a 3-year period after transplantation in 26 orthotopic heart transplant recipients showed persistently normal nitroglycerin-induced vasodilation. The vasodilator response to nitroglycerin did not predict development of graft arteriopathy; the presence of graft arteriopathy did not prevent a substantial vasodilator response to nitroglycerin.     

大隐静脉源性血管平滑肌细胞表型转化的研究进展

血管平滑肌细胞(VSMCs)表型转化是血管重塑的细胞学基础。收缩表型和合成表型VSMCs反映不同的功能,且两者之间可相互转化。笔者就大隐静脉源性VSMCs表型转化的概念及特点、表型标记物、细胞增殖和迁移,以及基质金属蛋白酶及其抑制物、细胞凋亡、表观遗传学与其表型转化的关系等研究进展进行归纳叙述,旨在为寻找防治静脉曲张相关的药物作用靶点提供理论基础。     

Iododeoxyuridine uptake in proliferating smooth muscle cells: an in vitro model to assess drug effects on intimal hyperplasia

Purpose To assess the maximum uptake of Iododeoxyuridine (IUdR) by proliferating smooth muscle cells in vitro to determine the optimal concentration to be administrated in an in vivo experiment. The long-term goal is to utilize radioactive IUdR to inhibit smooth muscle cell proliferation and restenosis of arteries after balloon angioplasty in vivo. Methods Porcine smooth muscle cells (SMCs) were cultured in 5% FBS medium and stimulated to proliferate by the addition of medium containing 10% FBS and insulin. IUdR was added at 5 μM, 10 μM, 20 μM, 30 μM, 40 μM, respectively, in proliferating SMCs with control for 1, 3, 5, 7 day incubation. Fluorescence Activated Cell Scanning (FACS) was performed after the SMCs were harvested and double-stained with FITC-conjugated anti-IUdR antibody (B44) and propidium iodide (PI). The ratio of IUdR-labeled cells to total cell population for each IUdR concentration and duration was determined by FACS. All data were repeated three times at each time point. The doubling times, growth curve and cell density of the proliferating SMCs were investigated using Beckman Coulter Particle Counter and digital microscopy. Results The percentage of proliferating SMCs uptaking IUdR increased from 1 to 5 days incubation with all concentrations of IUdR; In day 5, the uptake rate reached the peak value, then decreased by 7 days. IUdR uptake on day 5 was higher with concentrations of 10 μM and 20 μM. The doubling times of the SMCs were prolonged with IUdR concentration increasing, while the proliferating cell number and density compared with control decreased obviously by day 5 (P~0.05). Conclusion The peaktime to uptake IUdR was 5 days and optimal concentration of IUdR was betweenl0 μM to 20 μM for proliferating SMCs to uptake in vitro. IUdR itself could inhibit the SMCs““ proliferation and the inhibitory effect was related to the concentration.     

Quantitative analysis of survival of transplanted smooth muscle cells with real-time polymerase chain reaction

BACKGROUND: Cell transplantation improves heart function after myocardial infarction. This study investigated the survival of implanted cells in normal and infarcted myocardium. METHODS: Male rat aortic smooth muscle cells were cultured. For the in vitro study, male smooth muscle cells mixed with female smooth muscle cells or male smooth muscle cells injected into a piece of female rat myocardium were used to evaluate the accuracy of quantitative real-time polymerase chain reaction to measure Y chromosomes. For the in vivo study, 2 million live or dead male smooth muscle cells were injected into normal or infarcted female myocardium. At 1 hour and 1 and 4 weeks after transplantation, hearts, lungs, and kidneys were harvested for measurement of Y chromosomes. RESULTS: In vitro, the accuracy of polymerase chain reaction measurement was excellent in cultured cells (r2 = 0.996) and the myocardium (r2 = 0.786). In vivo, 1 hour after 2 x 10(6) cell implantation, live cell numbers decreased to 1.0 +/- 0.2 x 10 6 and 1.1 +/- 0.3 x 10(6) , and dead cell numbers decreased to 0.9 +/- 0.2 x 10(6) and 0.8 +/- 0.2 x 10(6) in the normal and infarcted myocardium, respectively (P < .01 for all groups). Lungs and kidneys contained 8.5% and 1.5% of the implanted cells, but no cells were detected at 1 week. At 1 week, no dead smooth muscle cells were detected in the normal or infarcted myocardium. The numbers of live cells at 1 and 4 weeks were 0.48 +/- 0.06 x 10(6) and 0.27 +/- 0.07 x 10(6) in normal myocardium and 0.29 +/- 0.08 x 10(6) and 0.18 +/- 0.05 x 10(6) in infarcted myocardium. CONCLUSIONS: One hour after implantation, only 50% of smooth muscle cells remained in the implanted area. Some implanted cells deposited in other tissue. Implanted cell survival progressively decreased during the 4-week study.     

血小板源性生长因子-BB对SD大鼠阴茎海绵体平滑肌细胞表型转化影响的初步研究

目的:研究血小板源性生长因子-BB(PDGF-BB)对SD大鼠阴茎海绵体平滑肌细胞(CCSMC)表型转化的影响。方法:改良组织块法原代培养大鼠CCSMC,并进行细胞免疫荧光鉴定。实验分为空白对照组和不同浓度(5、10、20、40 ng/ml)PDGF-BB组,处理24 h;以及空白对照组和20 ng/ml PDGF-BB作用细胞不同时间(24、48、72 h)组,利用qRT-PCR检测各组细胞α平滑肌肌动蛋白(α-SMA)、平滑肌肌球蛋白重链(SMMHC)、碱性调宁蛋白和骨桥蛋白(OPN)mRNA的表达。结果:原代培养CCSMCα-SMA阳性细胞率达95%以上。与空白对照组比较,不同浓度PDGF-BB作用大鼠CCSMC后α-SMA、SMMHC、碱性调宁蛋白的mRNA表达显著减少(P均0.05);OPN mRNA表达水平显著上调(P0.05)。与空白对照组比较,随20 ng/ml PDGF-BB作用细胞时间的延长,α-SMA、SMMHC、碱性调宁蛋白的mRNA表达显著减少,OPN mRNA表达水平上调,差异均有统计学意义(P均0.05)。结论:PDGF-BB可促使SD大鼠CCSMC表型从收缩型向合成型转化。     

中药益坎胶囊对动脉性勃起功能障碍大鼠阴茎海绵体平滑肌细胞表型转化的影响

目的:探讨中药益坎胶囊对动脉性勃起功能障碍(ED)大鼠阴茎海绵体平滑肌细胞表型转化的影响,以揭示益坎胶囊治疗ED的机制。方法:选取SD大鼠50只,其中10只设为正常组,另40只通过结扎双髂内动脉造成动脉性ED模型。造模后将其中10只设为模型对照组,其余30只灌胃给予ED治疗中药益坎胶囊,浓度分别为1.88、0.94、0.47 g/kg。给药1个月后,经腹腔注射阿朴吗啡,观察大鼠呵欠次数和阴茎勃起次数;切取大鼠的阴茎组织标本,通过免疫组化法观测海绵体平滑肌细胞收缩型性标志物碱性调宁蛋白(calponin 1)和合成型标志物骨桥蛋白(OPN)的表达,实验组结果与正常组和对照组进行比较。结果:注射阿朴吗啡后,正常组大鼠勃起次数为(4.48±1.25)次,模型对照组为(1.63±0.22)次,两组比较,差异有统计学意义(P0.01);给药后,中药益坎胶囊高、中、低剂量组大鼠勃起次数有明显改善[高剂量:(3.05±1.37)次;中剂量:(2.98±0.16)次;低剂量:(1.75±0.40)次]。免疫组化结果显示,模型对照组大鼠海绵体平滑肌细胞calponin 1表达减少,而OPN表达增多,与正常组相比差异有统计学意义(P0.05);与模型对照组相比,给药后,中药益坎胶囊高、中、低剂量组大鼠海绵体平滑肌细胞calponin 1表达增多,OPN表达减少。结论:中药益坎胶囊能改善动脉性ED大鼠的勃起功能,抑制海绵体平滑肌细胞表型由收缩型向合成型转化。     

Propofol inhibits volume-sensitive chloride channels in human coronary artery smooth muscle cells

Volume-sensitive chloride channels (VSCC) play an important role in regulation of cell volume and electrical activity. Activation of vascular smooth muscle VSCC causes smooth muscle depolarization and contraction. We investigated the effects of propofol on VSCC in cultured human coronary artery smooth muscle cells by using the chloride-sensitive dye 6-methoxy-N-ethylquinolinium (MEQ). To activate VSCC, cells were superfused for 2 min with hypotonic gluconate solutions and then potassium thiocyanate solution. The percentage reduction in MEQ fluorescence during 60 s in the presence of potassium thiocyanate was measured and used as an index of VSCC activity. 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), a well characterized chloride channel blocker, and propofol were dissolved in hypotonic gluconate solution to test their effect on VSCC activity. The reduction in fluorescence was inversely related to osmolality, indicating that activation of VSCC is osmolality dependent. Hypotonic gluconate solution (210 mOsm/kg H(2)O) reduced fluorescence by 38.9% +/- 2.6% of the baseline value. The reduction in fluorescence was dose-dependently inhibited by NPPB. Propofol at 0.3, 1, 3, 10, 30, and 100 micro g/mL significantly inhibited the reduction in fluorescence to 23.6% +/- 4.8%, 19.7% +/- 7.4%, 18.2% +/- 3.5%, 17.6% +/- 5.0%, 15.8% +/- 3.1%, and 10.3% +/- 3.9% of the baseline value, respectively. Our results indicate that propofol inhibits VSCC in a dose-dependent manner in human coronary artery smooth muscle cells.     

Myocardin restores erectile function in diabetic rats: phenotypic modulation of corpus cavernosum smooth muscle cells

This study aimed to investigate whether gene transfer of myocardin to the penis of diabetic rats can modulate corpus cavernosum smooth muscle (CCSM) cells phenotype and restore erectile function. Five normal control rats, and 22 diabetic rats were randomly divided into four groups: rats transfected with adCMV‐myocardin (N = 6), treated with empty vector (N = 6), injected with medium (N = 5), and sham‐operated rats (N = 5). The erectile response was measured 7 days after transfection. The percent of smooth muscle and the expressions of SMα‐actin, smooth muscle myosin heavy chain (SMMHC), calponin were evaluated. The increases in intracorporal pressure(ICP)/mean arterial pressure and total ICP in response to nerve stimulation in the adCMV‐myocardin treated rats were significantly greater than those in the empty vector (P < 0.001 and P < 0.001), medium only (P < 0.001 and P < 0.001), and sham‐operated rats (P < 0.001 and P < 0.001). The suppressed expressions of SMα‐actin, SMMHC and calponin were completely restored, and the amount of smooth muscle in diabetic rats were not restored after treatment. It is concluded that myocardin ameliorated erectile responses in diabetic rats mainly via promoting phenotypic modulation of CCSM cells from a proliferative to a contractile state.