BACKGROUNDCryopreserved conduit valved homografts (CVH) have been widely used in surgical treatment of cardiac disease. This study aimed to determine the extent of host cell ingrowth and the durability and immunogenicity of CVH, and to compare the performance of CVH stored at 4°C and CVH cryopreserved in liquid nitrogen at -196°C.

METHODSHeterotopic transplants of canine CVH stored at 4°C (n = 14) and cryopreserved in liquid nitrogen (n = 14) were made onto the abdominal aorta of recipient dogs. Animals were sacrificed at 7 and 15 days and at 1, 3, 6, 9, and 12 months after transplantation to excise the implanted CVHs. Tissue DNA extraction and quantitative polymerase chain reaction (PCR) were performed to calculate the ratio of donor cells and host cells in the CVH. The tissue viability of CVH after implantation was analyzed by detecting alkaline fibroblast growth factor 2 (FGF-2) using immunohistochemical staining and by observation under transmission electron microscope and scanning electron microscope.

RESULTSAll the animals survived and recovered well. There were few repopulating host cells (0.04% - 0.83%) in the implanted CVH at 7 or 15 days. The ratio of ingrowing host cells into the CVH continued rising after implantation and reached 40% - 47% in the 12th month postoperation. Histology, transmission electron microscopy and FGF-2 immunohistochemical staining indicated that fibroblasts and the host's endothelial cells were the main cellular elements invading the CVH. There were no significant differences in results between CVH stored at 4°C and CVH cryopreserved in liquid nitrogen.

CONCLUSIONSHost cells growing into CVH are very important for maintaining the long-term structure and function of the implanted CVH. There is no significant difference between CVH storing at 4°C or in liquid nitrogen in regard to the ingrowth of host cells or of morphologic features after CVH allografting.

Animals ; Aorta ; transplantation ; ultrastructure ; Dogs ; Immunohistochemistry ; Microscopy, Electron, Transmission ; Polymerase Chain Reaction ; Pulmonary Artery ; transplantation ; ultrastructure ; Transplantation, Homologous ; methods

Butylated hydroxytoluene (BHT) can inhibit experimental atherosclerosis in animals. Although the agent is an antioxidant, the exact mechanism of the reaction in atherosclerosis is still unknown. To investigate the effects of BHT on expression of P-selectin (PADGEM, GMP-140), intercellular adhesion molecule-1 (ICAM-1) and class II MHC (Ia) antigen, we proposed an experiment on rats. Male rats (n=18 per group) were fed either a normal cholesterol control diet, a normal cholesterol diet containing 0.5% BHT (BD), a high cholesterol diet containing 1.5% cholesterol and 0.1% sodium cholate (CD), or the CD diet containing 0.5% BHT (BCD). Rats were sacrificed after 3 days, and after 1, 2, 4, 10, and 17 weeks of dietary treatment. Although there was no gross or light microscopic atherosclerotic lesions, scanning electron microscopy revealed monocytic adhesion to aortic endothelium and mild endothelial injuries in CD and BCD groups. Immunohistochemically, the addition of BHT to a high cholesterol diet inhibited P-selectin expression but not in ICAM-1 and Ia antigen. These findings suggest that in rats, high cholesterol diets induce expression of ICAM-1, P-selectin and Ia antigen. In addition, the antiatherogenic effect of BHT may play a role in the inhibition of P-selectin.
Animal ; Antioxidants/pharmacology ; Antioxidants/metabolism* ; Aorta, Abdominal/ultrastructure ; Aorta, Abdominal/pathology ; Aorta, Thoracic/ultrastructure ; Aorta, Thoracic/pathology ; Butylated Hydroxytoluene/pharmacology ; Butylated Hydroxytoluene/metabolism* ; Cholesterol/metabolism ; Cholesterol, Dietary/metabolism* ; Male ; Microscopy, Electron, Scanning ; P-Selectin/biosynthesis* ; Rats ; Rats, Sprague-Dawley

The presence of elastin layers in the aortic walls of twelve human fetuses was confirmed with scanning electron microscope pictures after hot alkali treatment and histochemical examination. In addition, the number of elastin layers in aortic walls of 5 different segments were compared in fetuses of varying ages. Aldehyde fuchsin stained slides of elastin ascending aortas showed a range between 27 and 55 layers of elastin in fetuses of 8 weeks to 32 weeks. However, in the lower abdominal aortas, elastin layers decreased from 28 to only 3 layers for fetuses of the same age. Furthermore, as elastin layers decreased from ascending aorta to abdominal aorta with the progression of fetal life, similar changes in the elastin lamellae were observed. These results suggest that while aortas grow rapidly in length, the medial elastin thickens slowly, perhaps due to slow development of hydrodynamic forces and pressures. Also the adventitial elastin appears to lose out gradually along the length from ascending aorta to abdominal aorta.
Aorta/*embryology/metabolism/ultrastructure ; Elastin/*metabolism ; Fetus/anatomy & histology/*metabolism/physiology ; Human

OBJECTIVESTo investigate the method of preparing porcine thoracic aortas acellular tissue matrix (ACTM) by trypsin, EDTA and Triton X-100 and to find the best concentration of X-100.

METHODSA total of 56 roots of fresh thoracic aortas (without adventitial tissue) from 80 kg-100 kg tame pigs were divided randomly into > groups, each containing 8 roots. Every vessel was put into a 50 ml centrifugal tube with a solution of 0.1% trypsin + 0.02EDTA in PBS for 24 h. After that, each group was separately immerged into a solution of 0.1%, 0.2%, 0.5%, 1.0%, 2.0%, 5.0%, 10.0% Triton X-100 for 144 h-240 h. Specimens were taken every 6 h. Specimens were stained with haematoxylin-eosin and observed grossly under the light and transmission electron microscopy.

RESULTSLight and transmission electron microscopy revealed that ACTM was composed of insoluble collagen, elastin, and some insoluble metamorphic organelles. The best concentration of Triton X-100 was 1% at the time of 176.25 h +/- 5.5 h.

CONCLUSIONSPorcine thoracic aortas ACTM can be obtained successfully through this procedure. Triton X-100 is a good reagent for preparing vessel ACTM.

Animals ; Aorta, Thoracic ; cytology ; surgery ; ultrastructure ; Blood Vessel Prosthesis ; Octoxynol ; pharmacology ; Swine ; Tissue Engineering ; methods

BACKGROUNDThe release of Weibel-Palade Bodies (WPB) is a form of endothelial cell activation. But the signal transduction pathway leading to WPB release is not yet defined. We hypothesized that small G-protein rac1 and reactive oxygen species (ROS) mediate the ligand induced release of Weibel-Palade Bodies.

METHODSWe tested this hypothesis by using wild-type and mutant adenoviral rac1 expression vectors, and by manipulating the production and destruction of superoxide and hydrogen peroxide in human aortic endothelial cells (HAEC).

RESULTSThrombin (1.0 Unit, 30 min) induced the increase of WPB release by 3.7-fold in HAEC, and that H2O2 (0.1 mmol/L, 30 min) induced by 4.5-fold. These results correlated with thrombin-stimulated activation of rac-GTP binding activity by 3.5-fold, and increase of ROS production by 3.4-fold. The dominant negative adenoviral rac-N17 gene transfer dramatically inhibited the release of WPB by 64.2% (control) and 77.3% (thrombin-stimulation), and decreased ROS production by 65.5% (control) and 83.6% (thrombin-stimulation) compared with non-infected cells, respectively. Anti-oxidants, catalase and N-acetyl-cysteine significantly decreased the release of WPB by 34% and 79% in control cells, and further decreased by 63.6% and 46.7% in rac-N17 transferred cells compared with non-infected cells. We also confirmed that rac1 was located upstream of ROS in the WPB release pathway.

CONCLUSIONSSmall G-protein rac1 medicates ligand-induced release of Weibel-Palade Bodies in human aortic endothelial cells, and the signal pathway of WPB release is a rac1-dependent ROS regulating mechanism.

Aorta ; ultrastructure ; Endothelial Cells ; ultrastructure ; Humans ; Reactive Oxygen Species ; Signal Transduction ; Thrombin ; pharmacology ; Weibel-Palade Bodies ; physiology ; rac1 GTP-Binding Protein ; physiology

AIMTo investigate the relationship between low androgen level and ultrastructure of vascular endothelium.

METHODSForty-eight male Sprague-Dawley rats were randomly divided into four groups: group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone (T) undecanoate; and group D, intact rats treated with 5alpha-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T (FT) and dihydrotestosterone (DHT) were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score (VESS) was computed.

RESULTSSerum T and FT concentrations of rats in group B were significantly lower than those of the other three groups (P < 0.01); DHT concentrations of group D rats were significantly decreased (P < 0.01) when compared with those of groups A and C. Rats in groups B and D rats (with low androgen levels) had obvious damage to their endothelial surfaces, which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS.

CONCLUSIONThese results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.

5-alpha Reductase Inhibitors ; Animals ; Aorta ; drug effects ; ultrastructure ; Dihydrotestosterone ; blood ; Endothelium, Vascular ; drug effects ; ultrastructure ; Enzyme Inhibitors ; pharmacology ; Male ; Orchiectomy ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood ; pharmacology

BACKGROUNDTelocytes (TCs) are a novel type of interstitial cells, which have been recently described in a large variety of cavitary and noncavitary organs. TCs have small cell bodies, and remarkably thin, long, and moniliform prolongations called telopodes (Tps). Until now, TCs have been found in various loose connective tissues surrounding the arterioles, venules, and capillaries, but as a histological cellular component, whether TCs exist in large arteries remains unexplored.

METHODSTCs were identified by transmission electron microscope in the aortic arch of male C57BL/6 mice.

RESULTSTCs in aortic arch had small cell bodies (length: 6.06-13.02 μm; width: 1.05-4.25 μm) with characteristics of specific long (7.74-39.05 μm), thin, and moniliform Tps; TCs distributed in the whole connective tissue layer of tunica adventitia: TCs in the innermost layer of tunica adventitia, located at the juncture between media and adventitia, with their long axes oriented parallel to the outer elastic membrane; and TCs in outer layers of tunica adventitia, were embedded among transverse and longitudinal oriented collagen fibers, forming a highly complex three-dimensional meshwork. Moreover, desmosomes were observed, serving as pathways connecting neighboring Tps. In addition, vesicles shed from the surface of TCs into the extracellular matrix, participating in some biological processes.

CONCLUSIONSTCs in aorta arch are a newly recognized complement distinct from other interstitial cells in large arteries, such as fibroblasts. And further biologically functional correlations need to be elucidated.

Adventitia ; cytology ; Animals ; Aorta ; cytology ; Aorta, Thoracic ; cytology ; Cell Communication ; physiology ; Connective Tissue Cells ; cytology ; ultrastructure ; Male ; Mice ; Mice, Inbred C57BL ; Microscopy, Electron, Transmission

Using SEM, we have observed surface structures of atherosclerotic lesions of human aortas obtained from autopsies ranging from 59 to 84 years of age (5 males and 4 females). We have found four major interesting features on the lumenal surface of the aortas: 1) blood cells including leukocytes adhering to the endothelial surface, 2) a de-endothelialized surface showing both elastogenesis and elastolysis, 3) abundant cholesterol-ester crystals in extracellular spaces, and 4) cave-like structures possibly suggesting new capillarization in the thrombotic atherosclerotic plaques. We concluded that SEM has a great value in revealing more interesting surface structures if morphological studies are previously done in detail so that the characteristic shapes can be identified, and perhaps then meaningful interpretations can be made on the mechanism of human atherogenesis.
Aged ; Aged, 80 and over ; Aorta/ultrastructure* ; Aortic Diseases/pathology* ; Arteriosclerosis/pathology* ; Human ; Male ; Microscopy, Electron, Scanning* ; Middle Age

OBJECTIVEBased on high fat diet induced the model of atherosclerosis (AS) in C57BL/6J mice, authors studied the effect of endurance exercise on the atherosclerostic formation.

METHODSForty eight 8-week-old C57BL/6J mice were divided into four groups randomly (n=12): control (group N), 12-week atherosclerosis model group(group H), 12-week atherosclerosis model plus 11-week treadmill training group (group H + E) and 22-week atherosclerosis model group (group HS). Then, we observed the effects of endurance exercise on the ultra structure of aorta by electron microscope.

RESULTSTwenty weeks of high fat diet could result in serious AS in mice while endurance exercise could significantly antagonize or restrain the occur of AS. In addition, 10 weeks of endurance exercise could alleviate the symptom of pathological changes which already happened on aorta wall.

CONCLUSIONIt indicated that endurance exercise could effectively prevent and cure AS that induced by high fat diet.

Animals ; Aorta ; ultrastructure ; Atherosclerosis ; etiology ; prevention & control ; Diet, High-Fat ; adverse effects ; Dietary Fats ; administration & dosage ; Male ; Mice ; Mice, Inbred C57BL ; Physical Conditioning, Animal ; physiology ; Physical Endurance ; physiology

In order to determine the precise mechanism of the interactions between different types of cells, which are common phenomena in tissues and organs, the importance of coculture techniques are becoming increasingly important. In the area of cardiology, artificial arteries have been developed, based on the understanding of physiological communication of the arterial smooth muscle cells (SMC), endothelial cells (EC), and the extracellular matrix (ECM). In the study of atherosclerosis, the modification of low-density lipoprotein (LDL), which result in the recruitment and accumulation of white blood cells, especially, monocytes/macrophages, and foam cell formation, are hypothesized. Although there are well known animal models, an in vitro model of atherogenesis with a precisely known atherogenesis mechanism has not yet been developed. In this paper, an arterial wall reconstruction model using rabbit primary cultivated aortic SMCs and ECs, was shown. In addition, human peripheral monocytes were used and the transmigration of monocytes was observed by scanning electron and laser confocal microscopy. Monocyte differentiation into macrophages was shown by immunohistochemistry and comprehensive gene expression analysis. With the modified form of LDL, the macrophages were observed to accumulate lipids with a foamy appearance and differentiate into the foam cells in the ECM between the ECs and SMCs in the area of our coculture model.
Animal ; Aorta/physiology* ; Aorta/cytology* ; Arteriosclerosis/etiology* ; Cell Differentiation/physiology ; Cell Movement ; Coculture ; Endothelium, Vascular/physiology ; Endothelium, Vascular/cytology ; Extracellular Matrix/metabolism ; Foam Cells/ultrastructure ; Foam Cells/cytology ; Macrophages/physiology* ; Macrophages/cytology ; Male ; Microscopy, Confocal ; Microscopy, Electron ; Microscopy, Electron, Scanning ; Monocytes/ultrastructure ; Monocytes/physiology ; Muscle, Smooth, Vascular/physiology ; Muscle, Smooth, Vascular/cytology ; Myosin/metabolism ; Protein Isoforms/metabolism ; Rabbits