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At least 703 records · Page 39Linked to original sources
PubMed2005

Artifact-free coronary magnetic resonance angiography and coronary vessel wall imaging in the presence of a new, metallic, coronary magnetic resonance imaging stent.

BACKGROUND: Coronary in-stent restenosis cannot be directly assessed by magnetic resonance angiography (MRA) because of the local signal void of currently used stainless steel stents. The aim of this study was to investigate the potential of a new, dedicated, coronary MR imaging (MRI) stent for artifact-free, coronary MRA and in-stent lumen and vessel wall visualization. METHODS AND RESULTS: Fifteen prototype stents were deployed in coronary arteries of 15 healthy swine and investigated with a double-oblique, navigator-gated, free-breathing, T2-prepared, 3D cartesian gradient-echo sequence; a T2-prepared, 3D spiral gradient-echo sequence; and a T2-prepared, 3D steady-state, free-precession coronary MRA sequence. Furthermore, black-blood vessel wall imaging by a dual-inversion-recovery, turbo spin-echo sequence was performed. Artifacts of the stented vessel segment and signal intensities of the coronary vessel lumen inside and outside the stent were assessed. With all investigated sequences, the vessel lumen and wall could be visualized without artifacts, including the stented vessel segment. No signal intensity alterations inside the stent when compared with the vessel lumen outside the stent were found. CONCLUSIONS: The new, coronary MRI stent allows for completely artifact-free coronary MRA and vessel wall imaging.

Animals↗
PubMed2005

Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation.

Edema occurs in asthma and other inflammatory diseases when the rate of plasma leakage from blood vessels exceeds the drainage through lymphatic vessels and other routes. It is unclear to what extent lymphatic vessels grow to compensate for increased leakage during inflammation and what drives the lymphangiogenesis that does occur. We addressed these issues in mouse models of (a) chronic respiratory tract infection with Mycoplasma pulmonis and (b) adenoviral transduction of airway epithelium with VEGF family growth factors. Blood vessel remodeling and lymphangiogenesis were both robust in infected airways. Inhibition of VEGFR-3 signaling completely prevented the growth of lymphatic vessels but not blood vessels. Lack of lymphatic growth exaggerated mucosal edema and reduced the hypertrophy of draining lymph nodes. Airway dendritic cells, macrophages, neutrophils, and epithelial cells expressed the VEGFR-3 ligands VEGF-C or VEGF-D. Adenoviral delivery of either VEGF-C or VEGF-D evoked lymphangiogenesis without angiogenesis, whereas adenoviral VEGF had the opposite effect. After antibiotic treatment of the infection, inflammation and remodeling of blood vessels quickly subsided, but lymphatic vessels persisted. Together, these findings suggest that when lymphangiogenesis is impaired, airway inflammation may lead to bronchial lymphedema and exaggerated airflow obstruction. Correction of defective lymphangiogenesis may benefit the treatment of asthma and other inflammatory airway diseases.

Adenoviridae↗
PubMed1999

Selective ablation of immature blood vessels in established human tumors follows vascular endothelial growth factor withdrawal.

Features that distinguish tumor vasculatures from normal blood vessels are sought to enable the destruction of preformed tumor vessels. We show that blood vessels in both a xenografted tumor and primary human tumors contain a sizable fraction of immature blood vessels that have not yet recruited periendothelial cells. These immature vessels are selectively obliterated as a consequence of vascular endothelial growth factor (VEGF) withdrawal. In a xenografted glioma, the selective vulnerability of immature vessels to VEGF loss was demonstrated by downregulating VEGF transgene expression using a tetracycline-regulated expression system. In human prostate cancer, the constitutive production of VEGF by the glandular epithelium was suppressed as a consequence of androgen-ablation therapy. VEGF loss led, in turn, to selective apoptosis of endothelial cells in vessels devoid of periendothelial cells. These results suggest that the unique dependence on VEGF of blood vessels lacking periendothelial cells can be exploited to reduce an existing tumor vasculature.

Androgens↗
PubMed1984

Effects of vasodilators on the systemic capacitance vessels, a study with the measurement of the mean circulatory pressure in dogs.

There have been yet only a few studies on the action of vasodilators on the entire systemic capacitance vessels of the living body. In the present study, we studied the action of the vasodilators on the systemic capacitance vessels by measuring the mean circulatory pressure (MCP), introduced by Guyton, and that on the systemic resistance vessels from total peripheral resistance, in anesthetized open chest dogs. We also studied the venous return curves. Depending on vasodilators and the dosages used, resistance vessels could be dilated, but capacitance vessels could not be dilated. The reverse was never true. It was also found frequently that capacitance vessels could be dilated only when the tone of the capacitance vessels have been previously elevated by norepinephrine. Again, depending on vasodilators and their dosages, the venous return curves were changed in position and/or slope. We constructed a venous return curve by connecting 2 points on the venous return-right atrial pressure (VR-RAP) plane, one, VR-RAP plot, and the other, the point of VR = 0, RAP = MCP. Changes in the venous return curve caused by these vasodilators were classified into three types; (a) a clockwise rotation with a constant MCP, where one sees no change in MCP and decreased resistance to venous return (RVR), so that one may call this RVR-type, (b) a parallel shift of the venous return curve to the left, where one sees no change in RVR but a decreased MCP, so that one may call this MCP-type and (c) a shift to the left plus clockwise rotation, where one sees a decrease in MCP and decrease in RVR, so that this is a mixture of patterns (a) and (b). One may call this the mixed-type. The existence of the response of mixed-type is worth special attention, because, in this type, cardiac output (CO) was increased by the predominant decrease in RVR in spite of a decreased MCP, leading to an important condition that the CO does not necessarily decrease when systemic capacitance vessels were dilated by the vasodilators.

Animals↗
PubMed2003

Morphological changes in blood vessels produced by hyperosmotic agents and measured by optical coherence tomography.

Optical tissue clearing by hyperosmotic chemical agents significantly increases light depth penetration in skin and may improve light-based therapeutics such as laser treatment of cutaneous vascular lesions. A feasibility study was conducted to evaluate the potential role of optical clearing by glycerol in laser treatment of cutaneous vessels. Optical imaging was performed to investigate the morphological effects of glycerol on blood vessels of skin. Blood vessels were imaged using Doppler optical coherence tomography in in vivo hamster skin treated with glycerol. Images were obtained from the subdermal side to assess morphological changes in the blood vessels caused by glycerol and from the epidermal side to assess enhanced Doppler imaging of blood vessels. Application of glycerol to the subdermis resulted in venule stasis and for prolonged treatment times, arteriole stasis. In cases where flow remained in arterioles, an improved Doppler signal was detected from blood vessels when imaging transepidermally compared with the native condition. Intensity images indicated changes in blood optical properties and improved contrast of skin cross sections after glycerol application. The observed optical and morphological effects were reversed upon hydration of the skin with phosphate-buffered saline. The combination of increased depth of light penetration and the temporary slowing or cessation of flow in blood vessels could mean improved laser treatment of vessels.

Animals↗
PubMed2004

Transplanted bone marrow cells preferentially home to the vessels of in situ generated murine tumors rather than of normal organs.

Transplanted bone marrow-derived (BM) cells have been shown to home into the tumor vessels of s.c. implanted tumor models and to functionally contribute to tumor neoangiogenesis and tumor growth. However, whether BM cells contribute to the vessels of in situ developing tumors remains unknown. We have taken advantage of the in situ generation of mammary tumors in transgenic mice carrying the polyoma virus middle T oncogene (MMTV-PyVT) to determine whether transplanted BM cells home to and incorporate into the intratumoral vessels. Unfractionated BM from lacZ+ROSA 26 mice was used to rescue irradiated MMTV-PyVT transgenic mice or their wild-type congenics. All transgenic mice were sacrificed when they developed easily palpable mammary tumors. BM cells recruited and incorporated into the vasculature were identified by coexpression of lacZ and CD31, evidence that these cells had a distinctive, elongated appearance and that they lined the vessel structures. We found that BM cells home to and incorporate into 1.3% of the vessels of all in situ generated mammary adenocarcinomas examined (n=8). In contrast, BM cells did not recruit into the vessels of colon or liver of the tumor-bearing mice. Whether these cells contribute to new vessel formation via vasculogenesis or angiogenesis or simply attach to, and integrate into, the growing tips or shafts of pre-existing vessels has to be determined. BM could be used as a vehicle for the specific transport of antiangiogenic signals into the tumor vascular bed.

Animals↗
PubMed2004

Observation of lymphatic vessels in orbital fat of patients with inflammatory conditions: a form fruste of lymphangiogenesis?

In the absence of antibodies specific for lymphatic vessels, analysis of lymphatic vessels within different tissues has been widely performed with light microscopic and, most importantly, electron microscopic techniques. In regard to lymphatic vessels in the ocular globe and the periocular structures, controversy remains about the specific distribution of lymphatic channels. It is postulated that bulbar and retrobulbar tissues are devoid of lymphatic vessels, but lymphatic vessels have been demonstrated in lacrimal gland and epibulbar conjunctiva. In this study, we analyzed orbital fat for the presence of lymphatic tissue using D2-40, a monoclonal antibody, specific for lymphatic vessels. We found lymphatic vessels present within bulbar conjunctiva extending to the level of the ciliary apparatus. No lymphatics were identified in healthy anterior orbital adipose tissue. In two cases of orbital mucor-mycosis and one case of panendophthalmitis, significant lymphovascular proliferation was present within granulation tissue associated with the acute inflammation. We conclude that lymph vessel proliferation may be induced in inflammatory conditions in tissues which are normally devoid of lymph channels.

Adipose Tissue↗
PubMed2001

Missed anterior crossing vessels during open retroperitoneal pyeloplasty: laparoscopic transperitoneal discovery and repair.

PURPOSE: Extrinsic ureteropelvic junction obstruction due to anterior crossing segmental renal vessels is present in more than 50% of patients in adulthood. In this situation the ureter must usually be dismembered and transposed anterior to the crossing vascular structures, where it is anastomosed to the renal pelvis. Via the open retroperitoneal approach there may be a limited view of the anterior surface of the ureteropelvic junction and, hence, anterior crossing vessels may possibly be missed. We describe 2 patients with ureteropelvic junction obstruction in whom anterior vessels were missed during open retroperitoneal repair. Laparoscopic transperitoneal secondary pyeloplasty with posterior displacement of the crossing renal vessel was performed in each case. MATERIALS AND METHODS: Two patients presented with symptomatic congenital ureteropelvic junction obstruction after failed endopyelotomy in 1 and failed open retroperitoneal procedures in both. Preoperatively spiral computerized tomography angiography with a ureteropelvic junction protocol revealed crossing vessels in the 2 cases. This finding was confirmed at transperitoneal laparoscopic pyeloplasty. The ureter and renal pelvis were transposed anterior to the crossing vessels and 2 rows of running sutures were placed to complete the anastomosis. RESULTS: The 2 laparoscopic procedures were completed successfully. The anterior crossing vessels were preserved in each case. Currently the patients are asymptomatic and furosemide washout renal scan was normal. CONCLUSIONS: Spiral CT angiography reliably delineates the renal vascular anatomy in patients with ureteropelvic junction obstruction. This study may be valuable before planned open retroperitoneal ureteropelvic junction obstruction repair. Laparoscopic pyeloplasty may successfully manage anterior crossing vessels associated with secondary ureteropelvic junction obstruction.

Adolescent↗
PubMed2000

[Clinical application of artificial blood vessel graft for arteriovenous fistulization].

OBJECTIVE: To investigate the clinical application of artificial blood vessel graft for arteriovenous fistulization. METHODS: From October 1995 to August 1998, 23 cases with renal failure received PTEF artificial vessels grafting for arteriovenous fistulization in the forearm. The PTFE artificial vessel was 6 mm in diameter, and 40 cm in length. Artificial vessel "U"-shaped loop was formed from elbow incision to wrist incision, and perfused by 20 ml heparin saline. The two ends of artificial vessel were end-to-side anastomosed with superficial cubital vein and cubital artery respectively. RESULTS: All of arteriovenous fistulas were successfully formed, and could be performed hemodialysis periodically. The artificial vessels could be punctured repeatedly, and had sufficient volume of blood flow. It had no rejection, no formation of false aneurysm, and no ischemia in arm or exacerbated reflux to heart. CONCLUSION: The artificial vessel grafting for arteriovenous fistulization is a safe and convenient technique in clinical practice, especially when there is no autogenous vessels for arteriovenous fistula.

Aged↗
PubMed2004

[New vessels formation within intramural leiomyomata].

OBJECTIVES: The vessels of uterine leiomyomata seem to control the growth of the tumour. The aim of the study was to analyze the angioarchitecture of intramural leiomyomata and to observe vascular sprouting of the growing vessels in these tumors. MATERIAL AND METHODS: 28 myomatous uteri collected upon autopsy were injected via afferent vessels with Mercox resin and corroded after polymerisation of the resin. RESULTS: Two types of tumour vascularization were distinguished: tumors with few vessels invading the leiomyoma with few side branches and tumours with dense vascular "capsule" which was a source of small vessels supplying the tumour. Vascular sprouts were observed in majority of studied tumors. CONCLUSIONS: Pre-existing vessels undergo regression and new vessels grow from the periphery, as well as new vessels arise in the process of angiogenesis within the tumors.

Adult↗
PubMedDate not supplied

Colocalization of different types of amyloid in the walls of cerebral blood vessels of patients suffering from cerebral amyloid angiopathy and spontaneous intracranial hemorrhage: a report of 5 cases.

Four cases of spontaneous intracranial hemorrhage (ICH) are described in which the diagnosis of a cerebral amyloid angiopathy (CAA) was made in the biopsy specimens. In one further case CAA was detected on autopsy after intracranial hemorrhage (ICH). Amyloidotic degeneration of the vessel walls appeared to be the most likely reason for the ICH which in these cases especially involved superficial neocortical regions. In all cases, co-deposition of A4beta-amyloid and ALlambda-amyloid was found in diseased leptomeningeal and cortical vessels. Besides CAA, all 5 patients suffered from other diseases which had affected the blood vessel walls such as atherosclerosis, diabetes mellitus or arterial hypertension. However, no signs of systemic amyloidosis could be detected in these cases. It is suggested that the observed co-deposition of 2 amyloid subtypes is based on the combination of 2 different diseases, one of which results in a local production of A4beta-amyloid in the tunica media of cerebral blood vessels and another one, e.g. arterial hypertension, which impairs the permeability of the blood vessels by affection of the tunica intima allowing for the pathological penetration of circulating immunoglobulin lambda-light chains into the vessel wall. Subsequently, the preexisting A4beta-amyloid might have induced the polymerization of the lambda-light chains to ALlambda-amyloid in the media of the vessels and could have aggravated the amyloidotic degeneration of the vessel walls.

Adult↗
PubMed2005

Cost of single-vessel and multivessel coronary drug-eluting stenting: comparison to the DRG funding level.

BACKGROUND: Large-scale utilization of drug-eluting stents (DES) presents significant economic limitations, related to the current high cost of the device and the absence of adequate reimbursement from the health care system. The aim of the study was to evaluate the cost of single-vessel and multivessel drug-eluting stenting and to compare it with the DRG funding level. METHODS: Between November 2003 and May 2004, we studied 100 consecutive patients who underwent a percutaneous coronary intervention (PCI) with DES, 50 single-vessel and 50 multivessel procedures, in order to evaluate the real procedure costs of DES. The cost fields calculated in the analysis included: costs for the materials and drugs used in each procedure, costs related to medical personnel and staff, costs for equipment depreciations, and costs for total hospitalization based on the length of stay in the coronary care unit and/or in the cardiology ward. RESULTS: With regard to the 50 patients with single-vessel disease, 63 lesions were treated with 58 DES. With regard to the 50 patients with multivessel disease, the average number of treated vessels was 2.3 and of lesions 2.8. An average of 2.7 DES per patient was implanted; glycoprotein Ilb/IIIa inhibitors were used in 70% of cases. The multivessel procedure necessitated an average of 1.62 guide catheters, 1.86 guides, 1.36 balloons, and 475 +/- 124 ml of contrast medium; the average endoscopy time was 16 +/- 8 min while the total procedural time was 106 +/- 37 min. The procedural success rate was 100% for both groups. The post-PCI hospital stay was 2.1 +/- 1.7 days for patients with single-vessel disease and 2.8 +/- 2.6 days for patients with multivessel disease; the total was 4.7 +/- 2.8 and 6 +/- 3.2 days respectively. The mean total cost of hospital stay for PCI and DES was 6390 +/- 2274 Euro for single-vessel PCI and 9828 +/- 3026 Euro for multivessel PCI, split as follows: materials 2915 +/- 963 Euro and 5294 +/- 1177 Euro, procedural costs 404 +/- 55 and 446 +/- 99 Euro, costs of hospital stay 3070 +/- 2024 Euro and 4089 +/- 2517 Euro respectively for single-vessel and multivessel PCI. CONCLUSIONS: The mean total cost of a single-vessel PCI with DES falls within the DRG 112 reimbursement level for coronary angioplasty of 7006 Euro, while that of multivessel PCI with multiple DES is about 40% above the same reimbursement level. Interestingly, the multivessel PCI cost with multiple DES does fall within the reimbursement amount related to DRG 107 for bypass surgery procedures (14,322 Euro).

Aged↗
PubMed2005

[Evaluation of the proximal stenosis of native coronary vessels after coronary artery bypass grafting].

This study was designed to evaluate proximal native coronary stenosis (PNCS) after coronary artery bypass grafting (CABG). In 36 patients undergoing postoperative coronary arteriography, the PNCS bypassed with internal thoracic artery (ITA), saphenous vein graft (SVG) and right gastroepiploic artery (RGEA) progressed in 9 of 23 vessels (39%), in 15 of 28 vessels (53%), in 4 of 11 vessels (36%), respectively. Stenosis of no grafted coronary vessels progressed in 3 of 26 vessels (11%). Twelve native coronary vessels (9: 99% and 3: 90% stenosis vessels) bypassed with grafts were obstructed. This study confirms that the PNCS progresses significantly by CABG just after the operation and that it tends to progress highly with SVG in comparison with arterial grafts such as ITA or RGEA. Because operative mortality for repeated CABG is approximately twice as high as that for primary CABG, it is important to decide whether early postoperative percutaneous transluminal angioplasty is needed or not, in considering of future graft failure and stenosis progression of the native coronary vessels by CABG.

Aged↗
PubMed2006

Do parathyroid glands from individuals of different age and gender contain lymph vessels?

Whereas lymph vessels in some endocrine glands have been thoroughly investigated, data on these vessels in human parathyroid glands are often contradictory and deficient in available literature. Therefore, the aim of this study was to histomorphologically investigate whether lymph vessels could be found in human parathyroid glands postnatally and, if so, whether their presence was age- and gender-dependent. A total of 44 parathyroid glands from subjects of both genders, aged 4-90 years, were studied. The glands were divided into three groups. Those from the 1st and the 2nd age group demonstrated similar morphological structure of parenchyma with predominant chief cells with pale-staining cytoplasm, while the frequency of lymph vessels was lower in the 2nd group. Unlike in these groups, chief cells with dark- staining cytoplasm predominated in the glandular parenchyma of the 3rd age group where lymph vessels were not found in any of the examined glands. The frequency of lymph vessels in parathyroid glands was almost the same for both genders. Histomorphologic occurrence of lymph vessels coincided with the presence of endocrine cells with pale-staining cytoplasm, which allowed the assumption that lymph vessels were also one of the signs of functional activity of human parathyroid glands.

Adolescent↗
PubMed1991

[Development of artificial blood vessel suitable for cerebrovascular surgery: improvement in the mechanical properties].

Saphenous vein interposition grafts have been commonly used for the reconstruction of occlusive lesions in the extracranial cerebral arteries, such as carotid or vertebral arteries. In contrast, cerebral revascularization using an artificial blood vessel has not been so common. This is due to the fact that conventional artificial blood vessels have been too stiff for use in the cerebrovascular surgery. Another reason is that the patency rate of small-caliber artificial blood vessels has usually been inferior to that found in autologous vein grafts. The purpose of this study was to develop a pliable and compliant artificial blood vessel suitable for the reconstructive cerebrovascular surgery. This new artificial blood vessel is made of polyurethane, porous in structure (porous polyurethane). Thus, multiple small-sized pores exist both in the inner and outer surfaces, and in the wall of the graft. To test its mechanical properties, stress-strain curves and compliance were evaluated. In comparison to expanded polytetrafluoroethylene graft, which has been one of the most commonly used artificial blood vessels in the cardiovascular surgery, the mechanical properties of the porous polyurethane graft more closely resembled those of the common carotid artery in dogs. This means not only that it can be maneuvered with technical ease for anastomosis but also that there is a reduction of compliance mismatch between the host vessel and the artificial vessel. Compliance mismatch has been documented as a major factor in the inducement of intimal hyperplasia, which causes a delayed occlusion of the grafts. In the in vivo animal experiments, a porous polyurethane graft (2.3-3.2 mm in diameter, 40-50 mm in length) was transplanted into the common carotid artery of dogs. The mean size of pore varied from 0 (group 1), 1.7 (group 2), 4.4 (group 3), 5.5 (group 4), 7.4 (group 5), and 30.0 microns (group 6). In the follow-up study conducted 2 months after the transplantation, all grafts in group 4, 5, and 6 were shown to be patent, whereas no patency could be obtained in groups 1, 2 and 3. In addition, all grafts in group 6 were patent 6 months after transplantation, though one showed remarkable stenosis due to anastomotic intimal hyperplasia. Histological examination showed that the luminal surface of the graft was covered with monolayer of endothelium-like cells. Neoadventitia made of collagen developed around the external surface of the graft. Foreign body reactions were minimal. In conclusion, a porous polyurethane graft could be developed, which has improved mechanical properties suitable for the reconstructive surgery of the extracranial cerebral arteries.

Animals↗
PubMed1984

Pharmacological differentiation between large and small coronary vessels.

It has been reported that there are striking differences between large and small coronary arteries in their responsiveness to adenosine, nitroglycerin and catecholamines. The differential pharmacological responsiveness indicates differences in their excitation-contraction coupling mechanisms. Therefore, agents such as lyotropic anions (SCN-, NO3-, CH3SO4-) known to modulate these processes, and which by themselves do not have an inotropic effect, would be expected to differentially modulate the action of these substances on large and small coronary vessels. To test this hypothesis we studied the modulation by lyotropic anions of the effects of adenosine, nitroglycerin and verapamil on large and small intramural (0.5-0.6 mm diameter) dog coronary arteries. We have confirmed that small vessels are more sensitive to adenosine and verapamil and less sensitive to nitroglycerin than are large vessels. Replacement of Cl- by the lyotropic anions diminished the relaxing effects of adenosine in small vessels with the following order of potency, SCN- greater than NO3- greater than CH3SO4- greater than Cl-. NO3-. Replacement of Cl- resulted in almost total blockade of the adenosine response in small coronary arteries, whereas in large coronary vessels, the effects of nitroglycerin were reduced only 30%. The effects of verapamil in small vessels were slightly depressed whereas in large vessels its effects were unchanged. Our results further confirm that there are marked differences between the pharmacological responsiveness of large and small coronary vessels, indicating that these differences reside in the nature of their mechanisms controlling Ca++ translocation.

Adenosine↗
PubMed1980

Retinal vessel abnormalities of phototoxic retinopathy in rats.

Phototoxic retinopathy in rats is characterized by a progressive loss of the outer retinal layers. During the neural degenerative phases, a sequence of vascular change occurs. Whole mounts of ink-injected retinal vessels and flat mounts of trypsin-digested retinal vessels show areas of capillary nonperfusion and acellularity and enlargement of retinal capillaries in the deep bed. When the photoreceptor and outer nuclear layers have disappeared, portions of the remaining deep capillary bed become surrounded by cells of the retinal pigment epithelium (RPE). Thin sections show fenestrae in some vessel walls within the retinal pigment epithelial layer. Since serial sections show continuity between those fenestrated vessels and the deep retinal vessels and no evidence of vessels breeching Bruch's membrane, this morphologic phenomenon is considered to be an in situ alteration of retinal vessels. We conclude that a factor(s) within the retinal pigment epithelial layer determines the morphology of vessels within that environment.

Animals↗
PubMed1995

Ovarian angiogenesis. Phenotypic characterization of endothelial cells in a physiological model of blood vessel growth and regression.

Angiogenesis occurs during embryogenesis and is a down-regulated process in the healthy adult that is almost exclusively linked to pathological conditions such as tumor growth, wound healing, and inflammation. Physiological angiogenic processes in the adult are restricted to the female reproductive system where they occur cyclically during the ovarian and uterine cycle as well as during pregnancy. By systematically analyzing the phenotypic changes of endothelial cells during bovine corpus luteum (CL) formation and regression, we have established a physiological model of blood vessel growth and regression. Quantitation of vessel density, percentage of vessels with lumen, and ratio of Bandeiraea simplicifolia-I to von Willebrand Factor-positive endothelial cells were established as parameters of angiogenesis. Sprouting endothelial cells invade the growing CL and continue to grow throughout the first third of the ovarian cycle. Thereafter the mature CL is characterized by a dense network of vessels with gradually decreasing vessel density. During luteolysis and for several weeks thereafter (regressing and residual CL) all newly formed vessels regress, which is accompanied by gradual foreshortening and rounding of endothelial cells and subsequent detachment. Based on histochemical detection of nucleosomal fragmentation products physiological blood vessel regression in the cyclic CL does not appear to involve endothelial cell apoptosis. Lectin histochemical analysis revealed a distinct alteration of endothelial cell glycoconjugate expression during ovarian angiogenesis comparable with the distinct pattern of hyperglycosylation of cultured migrating endothelial cells (up-regulation of binding sites for Lycopersicon esculentum lectin, wheat germ agglutinin, neuraminidase-treated peanut agglutinin, and Ricinus communis agglutinin-I on sprouting ECs). Northern blot analysis of glycosyltransferases during the different stages of angiogenesis revealed an up-regulation of beta-galactoside alpha 2,6-sialyltransferase and alpha 1,3-galactosyltransferase mRNA expression during the angiogenic stages of CL formation. These data establish the ovarian angiogenesis model as a suitable experimental system to study the functional and phenotypic properties of endothelial cells in sprouting and regressing blood vessels and provide additional evidence for the importance of endothelial cell surface glycoconjugates during angiogenesis.

Animals↗