OBJECTIVETo investigate the possibility of constructing small-caliber artery by means of tissue engineering.

METHODSCell-PGA mixtures were made by separately seeding 1 x 10(7) smooth muscle cells and 5 x 10(6) endothelial cells isolated from neonate umbilicus onto PGA scaffold, the cell-PGA constructs were wrapped around a silicone tube before its implantation subcutaneously to nude mice and the mice were sacrificed in 2 and 6 weeks. The tissue engineered artery (TEA) were examined both grossly and immunohistochemically.

RESULTSThe gross appearance of TEA was similar to that of the natural counterparts; histologic and immunohistochemical analyses of the neoformed tissues revealed a typical artery structure, including the presence of EC at the luminal surface and the presence of SMC and collagen in the wall.

CONCLUSIONTEA with histology similar to natural vessel can be constructed by tissue engineering.

Animals ; Arteries ; surgery ; ultrastructure ; Endothelial Cells ; ultrastructure ; Immunohistochemistry ; Mice ; Mice, Nude ; Microscopy, Electron ; Muscle, Smooth, Vascular ; ultrastructure ; Tissue Engineering ; methods

The external elastic lamina (EEL) serves as a barrier for cells and macromolecules between the media and adventitia in the vascular wall. We evaluated the morphological changes and quantitative assessments of the EEL architecture in the coronary circulation of pigs fed with a high cholesterol diet. Confocal microscopy analysis of the EEL from hypercholesterolemic coronary arteries revealed an altered pattern characterized by fragmentation and disorganization of the EEL associated with an increase in the thickness. Computerized digital analysis of the images obtained by confocal scanning microscopy demonstrated that compared to normal coronary arteries, the EEL of hypercholesterolemic coronary arteries decreased in the percentage of their elastin content (30.80 +/- 1.64% vs. 47.85 +/- 1.82%, p = 0.001). The percentage of elastin content was negatively correlated with the vessel wall area (r = -0.82, p = 0.001). The immunoreactivity for matrix metalloproteinase-3 (MMP-3) increased in cholesterol-fed coronary arteries, predominantly in the neointima and adventitia. This study demonstrates that experimental hypercholesterolemia induced ultrastructural changes of the EEL in coronary circulation. The EEL may also be an atherosclerosis-prone area compared with the intima. The EEL may play an important role in the development of structural changes which characterizes the early phase of coronary atherosclerosis and vascular remodeling.
Animal ; Arteries/ultrastructure ; Arteries/enzymology ; Coronary Vessels/ultrastructure* ; Coronary Vessels/enzymology ; Elastic Tissue/ultrastructure* ; Elastic Tissue/enzymology ; Female ; Hypercholesterolemia/pathology* ; Hypercholesterolemia/enzymology ; Stromelysin 1/metabolism ; Swine

OBJECTIVEThe radial artery differs from internal mammary artery in its vascular biology and long-term patency after coronary artery bypass grafting (CABG). This study was designed to investigate their ultrastructural differences that may have implications in arterial remodeling and graft failure.

METHODSThirty-four radial artery and 11 internal mammary artery samples were obtained from patients underwent CABG, and subjected to routine electron microscopic examination. A semi-quantitative method was used to evaluate secretary endothelial cells, endothelial denudation, synthetic smooth muscle cells (SMCs), matrix accumulation, lipid deposition and medial submicroscopic calcification.

RESULTSCompared with internal mammary arteries, the radial arteries had more secretory endothelial cells (47.1%, 16/34 vs 27.2%, 3/ 11) and synthetic type SMCs in a background (14.4% vs 0.9%) that had more intimal lipid deposition and matrix accumulation (14.7%, 5/34 vs 9.1%, 1/11). Matrix vesicles and calcifications were frequently present in the media of both types of arteries. The calcifications, however, could not be visualized by routine histological stains, and therefore, named as submicroscopic calcification in this study. Fewer endothelial denudations were observed in the radial arteries, but no differences in medial lipid deposition and submicroscopic calcification were observed between these two types of arteries. The ultrastructural features and the arrangement of medial SMCs in radial arteries were similar to those of internal mammary arteries.

CONCLUSIONSRadial arteries have a higher SMC proliferative potential and more actively secretory status of endothelial cells, which may enhance the remodeling process and correlate with a decreased long-term patency. Better preservation of endothelial cells in radial arteries could be attributed to the "no touch" technique utilized in surgical harvesting. The significance of submicroscopic medial calcification during graft remodeling requires further investigations.

Calcinosis ; Coronary Artery Bypass ; methods ; Coronary Disease ; pathology ; surgery ; Endothelial Cells ; pathology ; ultrastructure ; Humans ; Male ; Mammary Arteries ; transplantation ; ultrastructure ; Microscopy, Electron ; Middle Aged ; Myocytes, Smooth Muscle ; pathology ; ultrastructure ; Radial Artery ; transplantation ; ultrastructure ; Tunica Intima ; pathology ; ultrastructure

Sutures may cause endothelial trauma and occlusion. The vascular clip system (VCS) clip applier may minimize endothelial injury. Fourteen carotid arteries of nine adult rabbits were transected and re-anastomosed with either #7-0 polypropylene (Group I, n=8) or VCS clips (Group II, n=6). The animals were sacrificed at 1, 3, 8, 14, and 30 days postoperatively. The operation time and bleeding amount were checked for each anastomosis. Carotid angiograms, photography, H&E staining and scanning electron microscopy (SEM) were performed. Fibrin and thrombus, inflammatory cell infiltration, endothelial disruption, luminal distortion, fibrosis, and wall thickening were compared. The luminal diameter was greater in group II. There were minimal differences in thrombosis, wall thickening and fibrosis between the two groups. However, fibrin, inflammatory cell infiltration, multinucleated giant cell formation, endothelial disruption, and luminal distortion were greater in group I. On SEM, group I showed trans-mural penetration. In contrast, group II showed suture margin eversion and no transmural penetration. Stenosis was greater in group I than in group II on carotid angiogram. The operation time was shorter in group II than in group I, i.e. 5+/-1.4 min vs. 11+/-3.8 min, respectively. The current data showed similar or superior results with VCS clips in comparison to conventional suturing with polypropylene.
Angiography ; Animal ; Arteriovenous Shunt, Surgical/*instrumentation/methods ; Carotid Arteries/pathology/*surgery/ultrastructure ; Microscopy, Electron, Scanning ; Rabbits ; Surgical Stapling/*instrumentation/methods

The aim of the present study was to evaluate the active and passive mechanical properties and wall collagen and elastin contents of mesenteric small arteries (MSAs) isolated from rats of 28-day simulated microgravity (SUS), countermeasure [S + D: SUS plus 1 h/d -G(x) to simulate intermittent artificial gravity (IAG)] and control (CON) groups. Three mechanical parameters were calculated: the overall stiffness (β), circumferential stress (σ(θ))-strain (ε(θ)) relationship and pressure-dependent incremental elastic modulus (E(inc,p)). Vessel wall collagen and elastin percentage were quantified by electron microscopy. The results demonstrate that the active mechanical behavior of MSAs differs noticeably among the three groups: the active stress-strain curve of SUS vessels is very close to the passive curve, whereas the active σ(θ)-ε(θ) curves of CON and S + D vessels are shifted leftward and display a parabolic shape, indicating that for MSAs isolated from S + D, but not those from SUS rats, the pressure-induced myogenic constriction can effectively stiffen the vessel wall as the CON vessels. The passive mechanical behavior of MSAs does not show significant differences among the three groups. However, the percentage of collagen is decreased in the wall of SUS and S + D compared with CON vessels in the following order: SUS < S + D < CON. Thus, the relationship between passive mechanical behavior and compositional changes may be complex and yet depends on factors other than the quantity of collagen and elastin. These findings have provided biomechanical data for the understanding of the mechanism of postflight orthostatic intolerance and its gravity-based countermeasure.
Animals ; Biomechanical Phenomena ; Collagen ; metabolism ; Elasticity ; Hindlimb Suspension ; physiology ; Male ; Mesenteric Arteries ; physiology ; ultrastructure ; Muscle, Smooth, Vascular ; physiology ; ultrastructure ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Stress, Mechanical ; Vasoconstriction ; physiology ; Weightlessness Simulation

OBJECTIVETo observe the histopathological changes of a novel small-caliber vascular graft after implantation in canine theca interna under scanning electron microscope.

METHODA 3 cm segment of the vascular graft (diameter of 4 mm) was implanted in an end-to-end fashion to bridge the severed carotid artery in 19 healthy dogs. Color Doppler sonography was performed 2 weeks after the operation to observe the patency rate of artificial blood vessel. At 1, 8, 12 and 24 week postimplantation, the arteries (4, 4, 6 and 5, respectively) were collected for optical and scanning electron microscopies after angiography to observe the patency of the arteries.

RESULTSOf the total of 19 arteries, occlusion occurred in 1 at 12 weeks and 1 at 24 weeks. Optical and electron microscopies showed that 1 week after implantation, slight fibroplasias and formation of red thrombus could be seen at the vascular anastomosis without endothelial cell lining. At 8 weeks, the host tissue grew into the lumen of the graft through the pores to form uniform neointima consisting of plenty of collagen fibers, but still without endothelial cells. At 12 weeks, discontinuous endothelial cells were seen to grow on the surface of the neointima. In the middle segment of the vascular graft, immature endothelial cells were found to grow in clusters. The structure of the neointima was loose in comparison with that at the anastomosis, with occasional inflammation cells. Twenty-four weeks after grafting, endothelial cells grew over the entire inner wall of the patent graft, and the surface of the neointima at the anastomosis was lined with continuous endothelial cells.

CONCLUSIONThe vascular graft can be useful for reconstruction of canine carotid artery defect and achieves good endothelialization 24 weeks after implantation.

Animals ; Blood Vessel Prosthesis ; Blood Vessel Prosthesis Implantation ; methods ; Carotid Arteries ; diagnostic imaging ; physiology ; surgery ; Collagen ; metabolism ; Dogs ; Endothelial Cells ; cytology ; metabolism ; ultrastructure ; Microscopy, Electron, Scanning ; Models, Animal ; Time Factors ; Tunica Intima ; cytology ; metabolism ; ultrastructure ; Ultrasonography, Doppler, Color ; Vascular Patency

The whole retina, except for the medullary fiber zone in a rabbit eye, is supplied by choroidal circulation. Therefore, the histopathological changes of the sensory retina due to choroidal circulatory disturbance in rabbits may be comparable to that of the human sensory retina in the case of ophthalmic artery occlusion. This study was carried out to evaluate the histopathological changes of the ischemic retina secondary to the occlusion of choroidal circulation. The experimental occlusion of all posterior ciliary arteries and anterior ciliary arteries in the horizontal rectus muscle of rabbit eyes was performed and the subsequent histopathological changes of the sensory retina were observed by transmission electron microscopy. The morphological changes of the sensory retina following the occlusion of the ciliary arterial system are as follows: severe loss of the inner and outer segments of the photoreceptor, mild to moderate degeneration of the ganglion cells, and excellent preservation of the Muller's cell fibers and the extension of the cytoplasmic villous processes to the cytoplasmic vacuolar spaces of other degenerated cells. These findings indicate that the Muller's fibers in the ischemic condition of retina might contribute to the formation of gliosis or scarring of a damaged retina.
Animals ; Arterial Occlusive Diseases/*complications ; Arteries ; Choroid/*blood supply ; Ciliary Body/*blood supply ; Ischemia/*etiology/pathology ; Rabbits ; Retina/*ultrastructure ; *Retinal Vessels

OBJECTIVETo investigate the effect of Quyu Xiaoban Capsule (QYXB) on the regressive treatment of atherosclerosis (AS) with acoustic densitometry (AD) technique.

METHODSEighty patients with AS were randomly divided into two groups, trial group was treated with QYXB and conventional medicine, and control group was treated with conventional medicine alone. Normal arterial wall and different types of atherosclerotic plaques were detected with AD technique before treatment and 10 months later.

RESULTSThe corrected averages in intimal echo intensity (AIIc%) were elevated in both groups but without significant difference, AIIc% of fatty plaques were increased in both groups and the value after treatment was significantly higher than that of pre-treatment in the trial group (68.12 +/- 5.54 vs 61.43 +/- 5.37, P < 0.05). The increment rate of AIIc% in trial group was significantly higher than that in control group (10.9 +/- 5.1% vs 2.5 +/- 5.5%, P < 0.05).

CONCLUSIONQYXB can stabilize the atherosclerotic plaque by increasing its acoustic density. Acoustic densitometry technique can differentiate the different histological plaques and monitor the histological changes of plaques during treatment.

Adult ; Aged ; Arteries ; diagnostic imaging ; drug effects ; Atherosclerosis ; diagnostic imaging ; drug therapy ; Capsules ; Carotid Stenosis ; diagnostic imaging ; drug therapy ; Densitometry ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Femoral Artery ; drug effects ; ultrastructure ; Humans ; Male ; Medicine, Chinese Traditional ; Middle Aged ; Ultrasonography

This study is to investigate the impairment and possible mechanism of endothelium-dependent relaxation of mice mesenteric arteries induced by mmLDL. Wire myography was employed to examine endothelial function of mesenteric arteries. Ultramicrostructure of mesenteric vascular beds were detected by transmission electron microscope. The results showed that endothelium cell edema and peeling, vascular elastic membrane fracture traces in mmLDL group. Endothelium-dependent relaxation was decreased in a time-dependent and dose-dependent manner by using mmLDL, compared with normal arteries. In endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation, the Rmax and pIC50 were decreased from (63 +/- 5) % and 6.42 +/- 0.09 of normal saline control to (31 +/- 3) % and 5.67 +/- 0.07 in mmLDL group (P < 0.001, P < 0.001), respectively. In nitric oxide (NO)-mediated relaxation, the Rmax and pIC50 were decreased from (45 +/- 4) % and 5.93 +/- 0.08 in normal saline control to (32 +/- 4) % and 5.43 +/- 0.11 in mmLDL group (P < 0.05, P < 0.01), respectively. There is no significant alteration of prostacyclin I2 (PGI2) pathway between these two groups. In conclusion, mmLDL induced the impairment of the ultramicrostructure of mesenteric vascular endothelium cell as well as the endothelium-dependent relaxation. The latter includes the dysfunction of NO- and EDHF pathway mediated endothelium-dependent relaxation.
Animals ; Biological Factors ; antagonists & inhibitors ; physiology ; Dose-Response Relationship, Drug ; Endothelial Cells ; drug effects ; ultrastructure ; Epoprostenol ; antagonists & inhibitors ; physiology ; Female ; Lipoproteins, LDL ; administration & dosage ; pharmacology ; Male ; Mesenteric Arteries ; cytology ; physiology ; ultrastructure ; Mice ; Mice, Inbred ICR ; Microscopy, Electron, Transmission ; Nitric Oxide ; antagonists & inhibitors ; physiology ; Vasodilation ; drug effects