Ultrastructure of the smooth muscle cells of the femoral artery in rats exposed to vibration

Electron microscopic study of femoral arteries of white rats exposed to prolonged general vibration at a frequency of 100 Hz with an amplitude of 0.5-0.7 mm has been performed. Light and dark smooth muscle cells, as well as unchanged cells have been found in the vascular media of experimental animals. Light cells are swollen with destroyed myofilaments and great number of microtubules in cytoplasm. Dark cells are characterized by coagulation necrosis and melting of myofilaments. Vibration was shown to cause marked structural changes in smooth muscle cells mitochondria: destruction of internal and external membranes, increasing matrix osmophilia or swelling of mitochondria accompanied by crista fragmentation, as well as matrix clarification and disappearance. Morphometric analysis indicates a considerably decreased energy production by smooth muscle cell mitochondria. It has been concluded that vibrations have a damaging effect on medial smooth muscle cells of the femoral artery in the experimental animals.     

Adaptive structures of the arteries of the heart participating in the regulation of coronary circulation

By means of a complex of anatomical, histological and histochemical methods cardiac vessels have been studied in 20 control dogs and in 84 dogs with experimentally produced circulatory disturbances peculiar for congenital heart diseases presented as an open arterial duct, coarctation of the aorta and the pulmonary trunk stenosis. The experimental animals have been observed for 6-12 months. In the animals with experimentally produced disturbances of the general and coronary hemodynamics hyperplasy in the coronary branches of the arteries appears, it is more pronounced in functionally loaded cardiac parts, as well as thickening of their walls at the expense of new formations and hyperthrophy of smooth muscle cells. In both control and experimental dogs in the coronary vessels at various branching levels certain formations are revealed; they are of compensatory-adaptive value: intimal and adventitial musculature, polypoid pulvinars, muscular-elastic constrictors, muscular cuffs and precapillary sphincters. They differ in structure, sources of their origin and in their functional value. Degree of their manifestation increases significantly after reproduction of the hemodynamic disturbances in the heart vascular system. The active role of these formations in regulation of the coronary circulation is demonstrated owing to a high content of ribonucleinic acid and glycogene in their smooth muscle cells and also an elevated succinate dehydrogenase, cytochromoxydase, acid and alcaline phosphatase activities.     

Heterogeneity of Intermediate Filament Expression in Vascular Smooth Muscle: A Gradient in Desmin Positive Cells from the Rat Aortic Arch to the Level of the Arteria Iliaca Communis

The display of the two distinct intermediate filament proteins, desmin and vimentin, in rat vascular smooth muscle tissue was studied by immunofluorescence microscopy on frozen sections of aorta and other blood vessels. Vascular smooth muscle cells present in these vessels always appeared rich in vimentin. However, staining of sections covering six distinct but contiguous parts of the aorta showed that the number of desmin containing cells was low distal to the truncus brachiocephalicus, but increases until in distal parts of the aorta and in the arteria iliaca communis almost all cells appear positive for desmin. Thus blood vessels show heterogeneity of intermediate filament expression not only in cross-section but can also display heterogeneity along their length. Muscular arteries such as the renal artery and the arteria femoralis, as well as arterioles and veins including the vena jugularis and the vena cava also contain desmin. Thus it may be that low numbers of desmin-positive cells are typical of elastic arteries, while muscular arteries and other blood vessels are characterized by large numbers of desmin-positive cells. We discuss whether desmin-positive and desmin-negative vascular smooth muscle cells may perform different functions and raise the possibility that desmin expression may coincide with the turn on of a specially regulated contractility program.     

Long-term cannulation of the vena cava of rats for blood sampling: local and systemic effects observed by histopathology after six weeks of cannulation.

A cannulation system with fixation by a metal cuff around the tail was used for blood sampling. The cannula was guided subcutaneously and positioned in the vena cava after entering the body via the femoral vein. Histopathology was performed after long-term cannulation of up to 35 and 45 days. The presence of the cannula in the vena cava induced endothelial hypertrophy and hyperplasia accompanied by stromal hypertrophy. The endothelial activation was not limited to the vena cava but was also observed in both the cannulated vena iliaca and the contralateral control vena iliaca, the latter showing only minor alterations. In the lung, thrombi were noted in the larger lung arteries; and foreign body emboli, probably situated in the alveolar septi, could be detected occasionally. Inflammatory reactions in the tail at the site of cuff fixation consisted of a mixture of acute and chronic inflammatory responses. The chronic inflammation extended into the tail muscles, as shown by the presence of fibrous tissue associated with muscle degeneration. In conclusion, prolonged venous cannulation in rats resulted in local alterations in the veins, small emboli in the lungs and a moderate to marked inflammation in the tail. However, the procedure itself was well tolerated by the animals.     

Morphological and biochemical characterization of remodeling in aorta and vena cava of DOCA-salt hypertensive rats

Arterial remodeling occurs in response to mechanical and neurohumoral stimuli. We hypothesized that veins, which are not exposed to higher pressures in hypertension, would demonstrate less active remodeling than arteries. We assessed remodeling with two standard measures of arterial remodeling: vessel morphometry and the expression/function of matrix metalloproteinases (MMPs). Thoracic aorta and vena cava from sham normotensive and DOCA-salt hypertensive rats (110 +/- 4 and 188 +/- 8 mmHg systolic blood pressure, respectively) were used. Wall thickness was increased in DOCA-salt vs. sham aorta (301 +/- 23 vs. 218 +/- 14 mum, P < 0.05), as was medial area, but neither measure was altered in the vena cava. The aorta and vena cava expressed the gelatinases MMP-2, MMP-9, transmembrane proteinase MT1-MMP, and tissue inhibitor of metalloproteinase-2 (TIMP-2). Immunohistochemically, MMP-2 localized to smooth muscle in the aorta and densely in endothelium/smooth muscle of the vena cava. Western and zymographic analyses verified that MMP-2 was active in all vessels and less active in the vena cava than aorta. In hypertension, MMP-2 expression and activity in the aorta were increased (59.1 +/- 3.7 and 74.5 +/- 6.1 units in sham and DOCA, respectively, P < 0.05); similar elevations were not observed in the vena cava. MMP-9 was weakly expressed in all vessels. MT1-MMP was expressed by the aorta and vena cava and elevated in the vena cava from DOCA-salt rats. TIMP-2 expression was significantly increased in the aorta of DOCA rats compared with sham but was barely detectable in the vena cava of sham or DOCA-salt hypertensive rats. These findings suggest that large veins may not undergo vascular remodeling in DOCA-salt hypertension.     

SERCA pump isoform expression in endothelium of veins and arteries: Every endothelium is not the same

Endothelium from rat aorta expresses sarco/endoplasmic reticulum Ca₂₊(SERCA) pump gene SERCA3 where as the smooth muscle expresses SERCA2. This has led to the postulate that vascular endothelium expresses SERCA3. To test this postulate, we examined the SERCA2 and SERCA3 mRNA expression in endothelium and smooth muscle dissected from coronary artery, coronary vein, aorta and vena cava of pig. Smooth muscle from all arteries and veins expressed only the SERCA2 mRNA. Endothelium from coronary artery, coronary vein and aorta expressed both SERCA2 and SERCA3 mRNA but the endothelium from vena cava did not express SERCA3 mRNA although it expressed SERCA2. These observations support the postulate that vascular endothelium expresses SERCA3 but the affirmation is equivocal because vena cava endothelium does not express SERCA3. (Mol Cell Biochem 000: 000-000, 1999)     

Status of the circulatory bed of the vascular membrane of the eyeball and retrobulbar structures during experimental venous stasis

In 43 test animals the state of the blood bed in the retrobulbar formations and the eyeball vasular tunic has been studied under venous congestion produced by ligation of the anterior vena cava (in dogs) and both external jugular veins (in rabbits). A complex of histological, histotopographic, morphometric and variation-statistical techniques has been used. The results obtained demonstrate that disturbances in the venous outflow in the anterior vena cava system produce certain responses in all parts of the retrotubular adipose tissue, of the eyeball muscles, of the optic nerve tunics, of the vascular tunic. Certain stageness is noted in the course of venous congestion. Places of the greatest morphological changes in the eyeball vascular tunic are determined. They are zones of vorticose veins formation and the area corresponding to the posterior pole of the eyeball. The analysis of the specific areas of the intermuscular arteries and veins cross sections demonstrates that in the reaction of these vessels to the different venous outflow in the anterior vena cava system these is certain unevenness in different ofthalmic muscles.     

Susceptibility of endothelial cells derived from different blood vessels to common viruses

Summary We examined whether endothelial cells derived from different blood vessels vary in their susceptibility to viral infection. Five common viral pathogens of humans (herpes simplex 1, measles, mumps, echo 9, and coxsackie B4 viruses) were evaluated for growth in endothelial cells derived from bovine fetal pulmonary artery thoracic aorta, and vena cava. All five viruses replicated in each type of endothelial cell. There were apparent differences in the quantities of measles and mumps viruses produced in pulmonary artery endothelium compared with thoracic aorta and vena cava when endothelial cells were obtained from different animals. However when pulmonary artery endothelial cells were compared with vena cava cells from the same animal, growth of each virus was similar in the two cell types. Four of the viruses replicated in the various endothelial cells without producing appreciable changes in cell morphology. These results indicate that endothelial cells from different blood vessels are equally susceptible to the human viruses evaluated, and that viral replication can occur without major alteration in cell morphology. Endothelial cells could serve as permissive cells permitting viruses to leave the circulation and initiate infection in adjacent tissues, including subendothelial smooth muscle cells. This work was supported by Public Health Service grants HL28220, HL 29492, and HL 24914 from the National Heart, Lung and Blood Institute, Bethesda, MD.     

Comparison of the numbers of plasmalemmal vesicles in arterial and venous endothelia of rats

The numbers of plasmalemmal vesicles in endothelial cells of rat blood vessels were determined on electron microscopic sections. In all vessels examined which included aorta and carotid and femoral arteries, vena cava and femoral vein, and lung and brain capillaries, the numbers were of the same order of magnitude. For arteries the numbers were about double those for the corresponding veins. About one-third of all vesicles could be stained with ruthenium red after its infusion into the vessels. The results make it improbable that differences in numbers of 'transport' vesicles in different types of blood vessel contribute significantly to the selective accumulation of atherogenic plasma proteins in arteries.     

Arterial identity of endothelial cells is controlled by local cues.

The ephrins and their Eph receptors comprise the largest family of receptor tyrosine kinases. Studies on mice have revealed an important function of ephrin-B2 and Eph-B4 for the development of the arterial and venous vasculature, respectively, but the mechanisms regulating their expression have not been studied yet. We have cloned a chick ephrin-B2 cDNA probe. Expression was observed in endothelial cells of extra- and intraembryonic arteries and arterioles in all embryos studied from day 2 (stage 10 HH, before perfusion of the vessels) to day 16. Additionally, expression was found in the somites and neural tube in early stages, and later also in the smooth muscle cells of the aorta, parts of the Müllerian duct, dosal neural tube, and joints of the limbs. We isolated endothelial cells from the internal carotid artery and the vena cava of 14-day-old quail embryos and grafted them separately into day-3 chick embryos. Reincubation was performed until day 6 and the quail endothelial cells were identified with the QH1 antibody. The grafted arterial and venous endothelial cells expressed ephrin-B2 when they integrated into the lining of arteries. Cells that were not integrated into vessels, or into vessels other than arteries, were ephrin-B2-negative. The studies show that the expression of the arterial marker ephrin-B2 is controlled by local cues in arterial vessels of older embryos. Physical forces or the media smooth muscle cells may be involved in this process.     

A high accumulation of minerals in human internal jugular vein

To elucidate age-related changes of mineral contents in human veins, the relative contents (RCs) of elements in the human internal jugular veins, superior and inferior venae cavae, and femoral veins from 27 subjects ranging from 40 to 98 yr old were analyzed by inductively coupled plasma atomic emission spectrometry. The average RCs of calcium in the 27 specimens were the highest in the internal jugular vein, followed in descending order by the superior vena cava, femoral vein, and inferior vena cava. The RCs of calcium and phosphorus in the internal jugular veins started to increase after the age of 50 yr, became the highest in subjects in their 60s and thereafter decreased gradually. It is noted that such accumulations of minerals, similar to the internal jugular vein, were also found in the veins, such as the superior and inferior venae cavae, and femoral vein. Accumulation of minerals in the veins is different from that of arteries, which increase progressively by aging, but do not decrease.     

Localization of 3H-estradiol in the uterus of pregnant and non-pregnant armadillos

Summary The uptake and retention of radiolabeled estradiol by the uterus was examined in the armadillo. One pregnant and two non-pregnant armadillos were treated with 1.4 g/kg body weight of ³H-estradiol (E₂) by injection into the left ventricle, and one non-pregnant animal was injected with both the labeled hormone and 140 g/kg body weight of unlabeled E₂. One and a half hour after injection, the animals were sacrificed and the uteri were removed and processed for autoradiography. In the non-pregnant animals, nuclear localization was observed in the interstitial cells and glandular epithelium of the endometrium and the connective tissue cells and smooth muscle of the myometrium. Additionally, there was a gradation of uptake in the epithelial cells of the endometrium in that the glandular cells of the basal region were heavily labeled, while those cells in the sinusoidal, and luminal regions contained successively less label. The luminal cells were poorly labeled. In the pregnant female, the smooth muscle and glandular cells hypertrophied and their nuclei contained less label than was observed in the non-pregnant animals. The arteries of the myometrium were more easily distinguished in the pregnant animals and the nuclei of the endothelial cells and smooth muscle were more consistently labeled than those of the non-pregnant armadillos.     

Intermediate filament heterogeneity in normal and hypercholesterolemic rabbit vascular smooth muscle cells

We have examined the intermediate filament (IF) protein content of vascular smooth muscle (SM) cells from several arteries and veins in rabbits and quantitated the changes which occur in SM cell expression of these proteins in response to cholesterol feeding. Cells from control rabbit arteries expressed 30% of their IF protein as desmin, while veins expressed 50% as desmin. During development of diet-induced atherosclerosis, morphological changes in arterial SM cells in the intima correlate with changes in IF expression. There is a significant increase in total IF protein content, vimentin increased differentially in thoracic aorta and desmin in pulmonary artery. In abdominal aorta both increase equally. Cholesterol feeding also resulted in changes in the expression of subspecies of desmin, vimentin, and actin in the thoracic arch. Although cholesterol feeding did not produce obvious morphological changes in the veins examined, venous SM IF protein expression was also altered. In the vena cava of cholesterol-fed rabbits there was an increase in vimentin expression without the parallel increase in desmin that occurred in the arterial system. These studies show that cholesterol feeding of rabbits induces measurable changes in the amounts of IF proteins in both arterial atherosclerotic lesions and venous SM cells.     

Prostanoid synthesis by vascular slices and cultured vascular cells of piglet aorta

Biosynthesis of prostanoids was studies in vascular slices of human umbilical arteries, piglet aorta and vena cava as well as in cultured vascular cells of piglet aorta. After preincubation with radioactive labeled arachidonic acid, prostanoids in the incubation media of slices or cultured cells were measured by radioimmunoassay or by radioactivity determination of labeled compounds following separation on reserved-phase high performance liquid chromatography. In all vascular slices 6-keto-PGF1α was the main prostanoid found, followed by PGE2. Thromboxane B2 and PGF2α were also formed, but only in trace amounts. In cultured cells taken from the three layers of the vascular wall, the prostanoid profiles differed markedly from those obtained from vascular slices. Each cell strain showed a specific prostanoid pattern. Endothelial cells synthesized predominantly 6-keto-PGF1α and PGF2α. In smooth muscle cells no 6-keto-PGF1α could be detected; here the predominant prostanoid was PGE2. PGF2α was formed in smaller quantities. Fibroblasts synthesized all prostanoids (PGE2, PGF2α, TXB2, 6-keto-PGF1α), PGE2 and PGF2α being the major products. In vascular slices and in cultured endothelial cells, the predominant prostacyclin derivative detected was 6-keto-PGF1α; the enzymatic PGI2-metabolite, 6,15-diketo-PGF1α, could be detected only in piglet vena cava slices in small amounts.     

Morphologic changes in the coronary arteries in experimental coarctation of the aorta and following its correction

In 33 puppies 2-4 months of age the model of a congenital heart disease was made as coarctation of the aorta. In 6-12 months 18 animals were taken to study, and in 15 animals the coarctation was removed. The latter animals were observed for other 6-12 months. The hearts of both groups were separately weighed, and the vessels of the coronary system were studied by means of a complex of histological and morphometric methods. Simultaneously, the number of smooth muscle cells, as well as the area and volume of their nuclei in media of small coronary arteries were estimated. At the experimental coarctation of the aorta certain hypertrophic-hyperplastic changes in coronary arteries at all branching levels take place. They are of a compensatory-adaptive character and reflect certain reactions of the vascular wall to an increased coronary hemodynamics under conditions of hyperfunction and hypertrophy of the cardiac muscle. Surgical removal of the coarctation is accompanied with a reduce of the hemodynamic loading of the heart, diminished degree of hypertrophy of the organ and a marked decrease of the hypertrophic-hyperplastic changes in its vessels. At the same time, the cardiac vascular system is adapting to the new conditions of circulation: rearrangement of some coronary arteries and arterioles according to the closed type and reduction of circulation in the vascular branches which have lost their importance in feeding the myocardium.     

Differential processes of vascular smooth muscle cell differentiation within elastic and muscular arteries of rats and rabbits: An immunofluorescence study of desmin and vimentin distribution

Summary Two main populations of smooth muscle cells exist in the arterial media of adult mammals with respect to expression of two intermediate filament proteins: vimentin-positive/desmin-negative cells (V+/D-) and vimentin-positive/desmin-positive ones (V+/D+). However, it is still not understood how this phenotypic diversity is established. Since the proportion and the distribution patterns of the two muscle cell populations depend both on the type of blood vessel and the species examined, the aim of the present study was to determine and to compare their developmental origin in various artery segments from two different species. Using confocal scanning laser microscopy and sections stained by means of immunofluorescence, the distribution patterns of desmin and vimentin were compared in transverse sections of thoracic and abdominal aortas (elastic arteries) and of the femoral artery (muscular artery) of newborn and adult rats (n=12) and rabbits (n=12). The comparison of sections labelled with specific antibodies showed the existence of a subpopulation of smooth muscle cells in the aortas, but not in the femoral artery which expressed desmin in newborns but not in adults. These data suggest that the phenotype of smooth muscle cells in elastic arteries but not in muscular arteries is modulated during development.     

Ultrastructural characteristics of elastogenesis in the major arteries of the canine hindlimb during leg lengthening

In mature dogs ultrastructural peculiarities of elastogenesis in femoral and anterior tibial arteries have been studied at various stages of the bone elongation after Ilizarov method. From the end of the 1st week of distraction, metabolic activation of intimal smooth muscle cells is revealed, from the 2d week--in the middle tunic, and on the 5th-6th week--fibroblasts of adventitia of the arteries investigated, directed to biosynthesis of intracellular predecessors of elastin and microfibrils of the elastic fibers. This results in activation of elastogenic processes, elastic structures in all three tunics of the arteries are observed to newly form and rearrange. The factor that stimulates and maintains elastogenesis is strain of extension, that occurs in the vessels during the experiment. Elastogenesis in the major arteries, when the extremity is elongated, has much in common with development of elastic components in the vascular wall in animals during the process of physiological growth.     

Mitoses in hypertrophied smooth muscle tissue of the rat posterior vena cava]

Injection of colchicin to rats exposed mitotic dividing leukomyocytes in the hypertrophied muscle tissue of the posterior vena cava. Under these conditions mitotic index didn't exceed 1:1000-1:10000. Many of the cells were in the prophase, this being apparently associated with prolonged mitosis in the leiomyocytes of the vein.     

小鼠血管损伤后巨噬细胞与平滑肌细胞的相互作用

目的研究血管损伤后病变形成过程中的巨噬细胞与平滑肌细胞的相互作用。方法C57BL/6（6～8周龄）小鼠24只,右侧股动脉植入透明塑料微导管,制作小鼠血管损伤模型,术后给予特异性抗体AFS98及APB5,分别阻断巨噬细胞和平滑肌细胞增殖的信息传导通路。给药2周后采集股动脉组织,用免疫组织化学的方法对血管病变进行分析。结果小鼠股动脉血管损伤2周后,病变部位聚集了大量的巨噬细胞、平滑肌细胞。给予阻断巨噬细胞增殖的信息传导通路的特异性抗体AFS98后,病变部位的巨噬细胞数量显著减少,平滑肌细胞数量反而增多。相反,给予抑制平滑肌细胞增殖的抗体APB5后,病变局部平滑肌细胞数量减少,而巨噬细胞数量急剧增加。结论小鼠股动脉血管损伤后,构成病变的细胞主要为巨噬细胞与平滑肌细胞。这两种细胞在分化成终末成熟细胞的过程中,存在着相互拮抗的作用。     

Participation of the cava vein blood flow in forming the total venous return under influence of different modality stimuli on the circulation system

Participation of the anterior and posterior veins cava in forming the total venous return under pressor and depressor effects, stimulation of depressing foci of the medulla's ventral part, enhancement of pulmonary ventilation, hypoxia, hypothermia, administration of acetylcholine, histamine, corinfar, was shown to depend on the blood flow shift direction in each of the veins cava, dynamics of shifts' development in time, and intensity of the stimulus. In systemic responses, the blood flow shifts in the vena cava anterior much contribute to the total venous return at the maximum of the systemic arterial pressure rise (r = 0.87) whereas contribution of the vena cava posterior is the greatest during a later occurring increase in the venous return (r = 0.84). Along with increase in the stimulus intensity the vena cava anterior's part in forming the venous return becomes more limited whereas that of the vena cava posterior is enhanced.