Heterogeneity of smooth muscle cells in atheromatous plaque of human aorta.

This study was undertaken to investigate the expression of cytoskeletal proteins and the ultrastructure of cells in normal intima and atheromatous plaque of human aorta. It has been established, using double-labeling immunofluorescence, that smooth muscle cells (SMC) in normal aortic intima contain myosin, vimentin, and alpha-actin but do not react with antibodies against desmin. In contrast, 7 of 28 atherosclerotic plaques contained many cells expressing desmin in addition to the other cytoskeletal proteins characteristic of normal intima SMC. These cells were localized predominantly in the plaque cap and had the ultrastructural features of modulated SMC, ie, well-developed endoplasmic reticulum and Golgi apparatus. Besides, some cells in the 13 atherosclerotic plaques proved to be myosin, alpha actin, and desmin negative but contained vimentin and actin as revealed by fluorescent phalloidin. These cells were found in the immediate proximity of atheromatous material and reacted with a monoclonal antibody specific to SMC surface protein (11G10) but not with monoclonal anti-muscle actin (HHF35) and anti-macrophage (HAM56) antibodies. Electron microscopy of this plaque zone revealed that the cytoplasm of these cells was filled with rough endoplasmic reticulum and a developed Golgi complex. At the same time, a certain proportion of cells in this region retained morphologic features of differentiated SMC such as the presence of a basal lamina and myofilament bundles. The revealed peculiarities of cytoskeletal protein expression and the ultrastructure of cells in human aortic atherosclerotic plaques may be explained by a phenotypic modulation of vascular SMC.     

Role of smooth-muscle cells in the formation of the atherosclerotic plaque

The role of smooth muscle cells in the formation of atherosclerotic plaques was studied by the fluorescent antibody method on autopsy material with the aid of antiserum against smooth-muscle actomyosin. The principal forms of atherosclerotic lesion (lipid stain, fibrous plaque, atheromatous plaque) were investigated in the aorta, the brain vessels, and the coronary arteries. Smooth-muscle cells were found in the intima along with atherosclerotic foci, in the lipid stain and fibrous tissue of the plaque, but not in the atheromatous masses. Proliferation and migration of smooth-muscle cells are regarded as an essential factor in the morphogenesis of atherosclerosis.Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 6, pp. 110–113, June, 1975.     

Effect of ethaphon on the calcium ion concentration in smooth-muscle cells of the aorta

Department of Molecular Pharmacology and Radiology, N. I. Pirogov Second Moscow Medical Institute. Department of Pharmacology, Voronezh Medical Institute. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 8, pp. 146–148, August, 1991.     

Spontaneous rupture of aortic arch through an atheromatous plaque resulting in pseudoaneurysm.

An autopsy case of spontaneous rupture of aortic arch through an atheromatous plaque which resulted in pseudoaneurysm is reported. The aorta was involved by severe atherosclerosis with scattered calcifications over the entire surface, and there was a fusiform aneurysm protruding from a transmural tear in the aortic arch. Histopathologically, no evidence of dissection or inflammatory change was noted in the aorta, and no histologic component of the aortic media was observed in the aneurysmal wall. However, degenerative change of cystic and laminar medial necrosis were recognized near the ruptured site. Such localized degenerative change was considered to be caused by circulatory disturbance which originated from disruption of the vasa vasorum due to aortic rupture.     

Contractile properties of smooth-muscle cells of the aorta during the development of experimental a therosclerosis

Contractile responses of smooth-muscle cells to the action of catecholamines and KCl at 27 and 37°C, under normal conditions and in the initial stages of atherosclerosis, were investigated in experiments on isolated ring segments of the rabbit aorta. The contractile responses of the atherosclerotic aorta induced by KCl were of lower amplitude than in the intact aorta, but the opposite pattern was found after the action of catecholamines. Lowering the temperature depresses the contractile responses of both the normal and the atherosclerotic aorta.Department of Normal Physiology, Leningrad Sanitary-Hygiene Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR, V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 9, pp. 1036–1038, September, 1976.     

The evolution of the atheromatous plaque: ultrastructural evidence

Our understanding of endothelial physiology is overdue compared with other areas of study. For too many years the complex mysteries of this thin single-layered cellular lamina covering the whole of the vascular network, from the large conduction vessel to the smallest resistance and diffusion vessel, have been hidden by an organ-based science more focused on organ pathology than on ultrastructural physiopathology. We tried to follow chronologically the alteration stages of this system of membranes in relation to the development of the atherosclerotic plaque in human biopsy.     

Determining the temperature distribution of swine aorta with simulated atheromatous plaque under pulsed laser irradiation: an experimental attempt to detect the vulnerability of atherosclerosis

We developed a method to determine the temperature distribution of swine aortas with simulated atheromatous plaques in order to measure the temperature of atherosclerotic lesions. The inflammation associated with temperature elevation is considered to be one of the aggravating mechanisms of atherosclerosis resulting in fissuring or rupture of atheromatous plaques. The temperature distribution of plaques covered by fibrous caps cannot be measured by conventional thermistors. Indocyanine green (ICG) solution was injected into the subintima of swine aorta to simulate the light absorption coefficient of human atheromatous plaques. The temperature distribution was calculated from measured temperature changes of the aortic intima under pulsed laser irradiation. The aorta was heated from the adventitial side with a halogen lamp to simulate the temperature elevation derived from inflammation. The temperature distribution of the aorta was obtained by solving the heat transfer equation using the surface layer thickness (corresponding to the fibrous cap thickness). The surface layer thickness can be calculated using the following working formula: D( µm)=1363-398 &#150 T +35 &#150 T 2, where s s &#150 T s denotes intimal surface temperature change under pulsed laser irradiation. The calculated temperature of the ICG layer (corresponding to the atheromatous core) correlated well with the measured temperature (r=0.97, p<0.0001).     

Desensitization of guanylyl cyclases in cultured human airway smooth-muscle cells

We previously showed that cultured human airway smooth-muscle cells (HASMC) contain soluble and particulate guanylyl cyclases (GCs). We studied the desensitization of soluble and particulate GCs in HASMC. Homologous desensitization of soluble GC occurred after incubation with S-nitroso-N-acetyl pencillamine (SNAP). SNAP-dependent desensitization was blocked by hemoglobin, a nitric oxide (NO) scavenger, suggesting that it was due to NO release. Cross-desensitization between SNAP and sodium nitroprusside (SNP) and the lack of thiol reduction after SNAP or SNP treatment suggested that thiol depletion was not involved. Assays for soluble GC activity and experiments using protein synthesis inhibitors suggested that SNAP-dependent desensitization was due to reduced soluble GC. Homologous desensitization of particulate GC occurred after pretreatment with atrial natriuretic peptide (ANP) accompanied by reduced particulate GC activity. Recovery required protein synthesis, suggesting that it was due to reduction in particulate GC. Homologous desensitization to either SNAP or ANP was not altered by phosphodiesterase (PDE) inhibitors, suggesting that increased PDE activity was not involved. Cross-desensitization experiments using SNAP and ANP and experiments using zaprinast to elevate cyclic guanosine monophosphate showed no evidence of heterologous desensitization. Our results suggest that pretreatment of HASMC with SNAP or ANP causes homologous, but not heterologous, desensitization of soluble and particulate GCs, respectively.     

抗原特异性调节性T细胞的诱导及其对粥样斑块形成的影响

目的：探讨抗原特异性CD4^＋CD25^＋T细胞的体外诱导及其对动脉粥样硬化斑块形成的影响。方法：从apoE^-/-小鼠骨髓提取并培养出未成熟树突状细胞，体外诱导热休克蛋白60特异性调节性T细胞；通过混合淋巴细胞反应研究CD4^＋CD25^＋T细胞的特异抑制性；过继转移CD4^＋CD25^＋T细胞后，观察小鼠动脉粥样斑块的形成状况。结果：阿司匹林处理的树突状细胞共刺激分子CD80和CD86表达减少；未成熟树突状细胞比成熟树突状细胞能诱导更多的特异性CD4^＋CD25^＋T细胞，后者在体外能明显抑制效应性T细胞的增殖和IFN-γ的产生；过继HSP60特异性CD4^＋CD25^＋T细胞组小鼠斑块面积较小。结论：未成熟树突状细胞可诱导出抑制功能强大的HSP60特异性CD4^＋CD25^＋T细胞，后者在体内能明显抑制斑块的形成。     

Pentose-utilizing variants of Novikoff hepatoma cells: Phenotypic characterization

Forty-three independent variants of the Novikoff hepatoma cell line have been isolated for their ability to use d-xylose,d-ribose, and/or l-arabinose as a sole carbon and energy source. The variants exhibited marked morphological changes and a loss or decrease of cloning efficiency in soft agar. The xylose and arabinose variants showed similar phenotypes while the ribose variants were a phenotypically heterogenous group. Two major classes of variants were found with regard to their specificity for pentoses: one class could grow on ribose, xylose, or arabinose, while the second class grew only on ribose. The lack of specificity for pentose use was correlated with the ability to use pentitols for growth. The frequency of pentoseutilizing clones was 5 × 10^–2 to 10^–3,and nitrosoguanidine treatment increased this frequency tenfold. Fluctuation analyses showed the appearance of pentoseutilizing variants to be a random event. Of the variants examined, 84% expressed a stable pentose phenotype, and of those, 6% were cold sensitive and 8% were temperature sensitive for pentose utilization. In addition to the suggested mutational basis for the pentose phenotype, two variants showed a large increase in chromosome number from 73 ±3 to 132 ±10.     

Determining the temperature distribution of swine aorta with simulated atheromatous plaque under pulsed laser irradiation: an experimental attempt to detect the vulnerability of atherosclerosis.

We developed a method to determine the temperature distribution of swine aortas with simulated atheromatous plaques in order to measure the temperature of atherosclerotic lesions. The inflammation associated with temperature elevation is considered to be one of the aggravating mechanisms of atherosclerosis resulting in fissuring or rupture of atheromatous plaques. The temperature distribution of plaques covered by fibrous caps cannot be measured by conventional thermistors. Indocyanine green (ICG) solution was injected into the subintima of swine aorta to simulate the light absorption coefficient of human atheromatous plaques. The temperature distribution was calculated from measured temperature changes of the aortic intima under pulsed laser irradiation. The aorta was heated from the adventitial side with a halogen lamp to simulate the temperature elevation derived from inflammation. The temperature distribution of the aorta was obtained by solving the heat transfer equation using the surface layer thickness (corresponding to the fibrous cap thickness). The surface layer thickness can be calculated using the following working formula: D(microm)=1363-398DeltaTs+35DeltaTs(2), where AT, denotes intimal surface temperature change under pulsed laser irradiation. The calculated temperature of the ICG layer (corresponding to the atheromatous core) correlated well with the measured temperature (r=0. 97, p<0.0001).     

Immunocytochemical study of the localization of scavenger receptor in human aortic smooth-muscle cells

Scavenger receptor was soughtin situ in human aortic smooth-muscle cells and in a primary culture of intact human aortic intima using antibodies to scavenger receptor. For identification of smooth-muscle cells, double staining making use of antibodies to murine α-actin was used. The presence of scavenger receptor in smooth-muscle cells of the intima and media of human aorta was demonstrated on aortic slices. In cultured smooth-muscle cells from normal human aortic intima scavenger receptor was distributed over the entire surface of the cell membrane, forming clusters in some places. These results suggest that human aortic smooth-muscle cells express scavenger receptor. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 8, pp. 195–198, August, 1995 Presented by V. N. Smirnov, Member of the Russian Academy of Medical Sciences     

The role of atheromatous plaque rupture in the genesis of myocardial infarction

The rupture of advanced atheromatous plaques initiates a significant number of cases of coronary artery thrombosis and subsequent myocardial infarction.$\text{Hypothesis}$: The range of outcomes following plaque rupture is determined to a large extent by the interaction between the turbulent arterial stream and the visco-elastic properties of the extruded atheromatous material. Thrombosis is a secondary event. Research into the visco-elastic behaviour of atheromatous material may predict predisposition to myocardial infarction.     

Synaptic potentials in smooth-muscle cells

Tests were carried out on the smooth-muscle cells (SMC) of the anococcygeus muscle of rats and rabbits by the double sucrose gap method with Krebs' solution containing tetraethylammonium (1 mmole/liter). Stimulation of a muscle strip from the anococcygeus of rats and rabbits by square pulses of maximal amplitude and short duration induced excitatory postsynaptic potentials (EPSPs) in rat and rabbit SMC and inhibitory postsynaptic potentials (IPSPs) in rabbit SMC. The amplitude of the postsynaptic potentials was a linear function of the membrane potential. Removal of chlorine ions from the external solution reduced the amplitude of EPSPs of SMC of the rabbit anococcygeus and shifted the reversal potential toward the sodium equilibrium potential. EPSP generation in SMC of the rabbit anococcygeus is evidently connected with an increase in membrane permeability to both sodium and chlorine ions.Department of Neuromuscular Physiology, A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. (Presented by Academican of the Academy of Medical Sciences of the USSR N. N. Gorev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 913–916, August, 1976. Original article submitted July 11.     

T lymphocyte lines isolated from atheromatous plaque contain cells capable of responding to Chlamydia antigens

Chlamydia pneumoniae infection is associated with atherosclerosis and the organism has been identified in arterial lesions. To determine whether T lymphocyte-mediated immune responses to Chlamydia antigens within plaque could contribute to pathogenesis, we have derived T cell lines from atherosclerotic plaques of 32 patients. Culture with IL-2 alone proved insufficient for cellular activation and expansion, but additional stimulation with phytohaemagglutinin (PHA) or recall antigens allowed consistent establishment of T cell lines. Furthermore, in cultures of approx. 500 tissue fragments, Chlamydia organisms proved as effective as other recall antigens in producing outgrowth of arterial T cells (20-25% wells produced T cell lines). Testing the antigen responsiveness of T cell lines showed that those derived using Chlamydia organisms were more likely to respond to Chlamydia (5/29+) than those isolated using other stimuli (6/69+ for PHA; 5/57+ for PPD and tetanus toxoid (TT)). However, lines responsive to each of the recall antigens were observed. Using recombinant Chlamydia antigens, some Chlamydia-specific T cell lines were shown to respond to OMP2 and/or hsp60. Those recognizing Chlamydia hsp60 did not cross-react with human hsp60, but human hsp60-responsive lines were also observed. Thus, atherosclerotic plaque tissue contains a variety of memory T lymphocytes, and amongst these are cells capable of recognizing Chlamydia antigens. In a C. pneumoniae-infected plaque, such T cells may be activated by local antigen and could contribute to the inflammatory process in the arterial wall through CD40 ligand expression and cytokine secretion.