Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peribiliary vascular plexus plays an important role in physiology of bile flow. Disturbance of the microcirculation may contribute to ductal injury, but little is known about alterations in the vascular supply of small bile ducts in liver disease. Immunoperoxidase stains for vascular endothelium (Ulex europaeus, factor VIII-related antigen, CD34) were used to study the peribiliary vascular plexus in 20 cases of primary sclerosing cholangitis (PSC) and 27 cases of primary biliary cirrhosis (PBC), two diseases characterized by bile duct destruction. Normal liver from 10 autopsy cases of sudden cardiac death was used as a control. Interlobular bile ducts (20- to 80-microm diameter) were identified on AE1/AE3 immunostain; vessels adjacent to the basement membrane of these ducts were counted. Normal interlobular bile ducts had an average of 2.15 vessels per duct (range, 1.68 to 2.71). Few PBC or PSC cases had a normal number of peribiliary vessels. There was a trend toward vasopenia at higher stage, although vascular loss was noted in early stages as well. The pattern of vascular loss was different for the two diseases; in PSC, the periductal capillaries were often preserved but were pushed away from the basement membrane by concentric deposits of collagen. Small residual vessels could be identified within fibrous scars of obliterated bile ducts in PSC. In 4 stage 3 or 4 PSC cases with little bile duct injury, vessel/duct ratio approached normal levels. In PBC, vessels were obliterated in areas of granulomatous inflammation and heavy lymphocytic infiltrate around bile ducts. In conclusion, loss of peribiliary vessels is common in PSC and PBC. Vessel loss is seen in early stages and may contribute an element of ischemia to continued small bile duct loss but is probably secondary to the inflammatory process.
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PMID:Peribiliary vascular plexus in primary sclerosing cholangitis and primary biliary cirrhosis. 922 46

Neovascularization in the adult central nervous system occurs as a response to several pathophysiological conditions such as ischemia, wound repair, or neoplasia. Endothelial cells from different blood vessel types, different organs, and different species are heterogeneous; therefore, the appropriate cell type should be used to study specific aspects of vascular pathology. We have developed a method to isolate human cerebral microvascular endothelial cells (CMECs) from small, freshly obtained specimens of normal brain adherent to human arteriovenous malformations (AVMs). The isolation procedure involves enzymatic digestions and gradient centrifugations, yielding over 95% pure primary cultures. Alternative isolation methods using magnetic beads, panning, or cloning were not superior with regard to cell purity or yield. CMECs were identified by their immunoreactivity for vWF, CD34, EN4, binding of Ulex europeus lectin, and uptake of DiI-Ac-LDL. They displayed ultrastructural features characteristic of blood-brain barrier endothelial cells and expressed GLUT-1. CMECs were subcultured; however, prolonged culture led to reduced culture purity. Vascular endothelial growth factor, basic fibroblast growth factor and hepatocyte growth factor/scatter factor stimulated the directional motility of CMECs, with dose-response profiles similar to human umbilical vein endothelial cells (HUVECs). In contrast, to stimulate proliferation, lower concentrations of growth factors tended to be necessary for CMECs than for the large vessel endothelial cells. CMECs formed capillary tube-like structures in an in vitro angiogenesis assay using matrigel. This study expands the spectrum of available tissue sources for the isolation of human neuromicrovascular endothelial cells, which are essential for the in vitro study of blood-brain barrier function and cerebral angiogenesis.
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PMID:Isolation and culture of human neuromicrovascular endothelial cells for the study of angiogenesis in vitro. 1034 68

Preclinical studies in animal models and early results of clinical trials in patients suggest that intramuscular injection of naked plasmid DNA encoding vascular endothelial growth factor (VEGF) can promote neovascularization of ischemic tissues. Such neovascularization has been attributed exclusively to sprout formation of endothelial cells derived from preexisting vessels. We investigated the hypothesis that VEGF gene transfer may also augment the population of circulating endothelial progenitor cells (EPCs). In patients with critical limb ischemia receiving VEGF gene transfer, gene expression was documented by a transient increase in plasma levels of VEGF. A culture assay documented a significant increase in EPCs (219%, P<0.001), whereas patients who received an empty vector had no change in circulating EPCs, as was the case for volunteers who received saline injections (VEGF versus empty vector, P<0.001; VEGF versus saline, P<0.005). Fluorescence-activated cell sorter analysis disclosed an overall increase of up to 30-fold in endothelial lineage markers KDR (VEGF receptor-2), VE-cadherin, CD34, alpha(v)beta(3), and E-selectin after VEGF gene transfer. Constitutive overexpression of VEGF in patients with limb ischemia augments the population of circulating EPCs. These findings support the notion that neovascularization of human ischemic tissues after angiogenic growth factor therapy is not limited to angiogenesis but involves circulating endothelial precursors that may home to ischemic foci and differentiate in situ through a process of vasculogenesis.
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PMID:Vascular endothelial growth factor(165) gene transfer augments circulating endothelial progenitor cells in human subjects. 1086 8

Endothelial cell progenitors, angioblasts, have been detected in the peripheral blood of adult humans, mice, and rabbits. These cells have been shown to incorporate into the endothelium of newly forming blood vessels in pathological and nonpathological conditions. Here we investigated the possibility that the CD34-expressing leukocytes (CD34(+) cells) that appear to be enriched for angioblasts could be used to accelerate the rate of blood-flow restoration in nondiabetic and diabetic mice undergoing neovascularization due to hindlimb ischemia. CD34(+) cells did not accelerate the restoration of flow in nondiabetic mice, but dramatically increased it in diabetic mice. Furthermore, CD34(+) cells derived from type 1 diabetics produced fewer differentiated endothelial cells in culture than did their type 2 diabetic- or nondiabetic-derived counterparts. In vitro experiments suggest that hyperglycemia per se does not alter the ability of angioblasts to differentiate or of angioblast-derived endothelial cells to proliferate. In contrast, hyperinsulinemia may enhance angioblast differentiation but impair angioblast-derived endothelial cell survival or proliferation. Our findings suggest that CD34(+) cells may be a useful tool for therapeutic angiogenesis in diabetics.
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PMID:Blood-derived angioblasts accelerate blood-flow restoration in diabetic mice. 1095 32

Reactive angioendotheliomatosis (RAE) is a rare benign cutaneous vascular proliferation characterized by intravascular hyperplasia of endothelial cells and tuft-like proliferation of vessels. A 75-year-old man had erythematous and violaceous macules, some stellate and others arranged in a livedoid pattern, evolving toward necrosis with central areas having an "atrophie blanche" appearance spread on the trunk, inguinal folds, and right thigh. He was on hemodialysis and had a benign monoclonal gammopathy. Cutaneous biopsy revealed RAE characterized by the proliferation of epithelioid and spindle-shaped cells in superficial and middermis lining vascular channels, arranged in clusters, and sometimes displaying an intravascular growth pattern. These cells stained for CD31, CD34, and actin. Interestingly, prominent amyloid deposits were found in the wall of some vessels in deep dermis, often causing obstruction of their lumina. The cause of RAE is unknown, but it can be associated with infections, antiphospholipid syndrome, dysglobulinemia, cryoproteinemia, and lower extremities arteritis, and it may occur near arteriovenous fistulas. In this patient, we believe that RAE was caused by obliteration of dermal vessels by amyloid deposits. Indeed, it is thought that RAE could be caused by ischemia secondary to vascular obstruction. This is the first reported patient with RAE associated with amyloid deposits.
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PMID:Reactive angioendotheliomatosis secondary to dermal amyloid angiopathy. 1148 23

A case of atypical decubital fibroplasia with unusual histology arising in the buttock of a 68-year-old bed-ridden male in presented. The lesion measuring 5.4 cm in greatest dimension was histologically characterized by a proliferation of fibroblasts with oval to spindle nuclei and dense fibrous stroma with focal hyalinization and calcification. Ganglion-like fibroblastic cells and multinucleated giant cells of osteoclast type were also observed. There were numerous elastic fibers within and adjacent to the proliferating stromal cells. The proliferating stromal cells were positive for vimentin and collagen type IV but negative for CAM 5.2, epithelial membrane antigen, desmin, alpha-smooth muscle actin, muscle actin, HHF35, S-100 protein and CD34. Ultrastructurally, they were of a fibroblastic nature. The hypercellularity, lack of zones of fibrinoid necrosis, lack of lobulation and the presence of multinucleated giant cells were different from the originally described lesion. This condition represents a variant of atypical decubital fibroplasia. Pathogenic factors of this lesion are considered to be chronically repeated pressure and associated intermittent ischemia. The recognition of the lesion and its distinction from a sarcoma is essential.
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PMID:Atypical decubital fibroplasia with unusual histology. 1187 17

Adult marrow-derived cells have been shown to contribute to various nonhematologic tissues and, conversely, primitive cells isolated from nonhematopoietic tissues have been shown to reconstitute hematopoiesis. Circulating endothelial progenitor cells (EPCs) have been reported to be at least partially donor derived after allogeneic bone marrow transplantation, and shown to contribute to neovascularization in murine ischemia models. However, it is unknown whether these EPCs are actually clonally derived from the same population of stem and progenitor cells that reconstitute hematopoiesis, or from another cell population found in the marrow or mobilized blood that is transferred during transplantation. To approach this question, we characterized circulating EPCs and also endothelial cells from large vessels harvested at autopsy from rhesus macaques previously transplanted with retrovirally transduced autologous CD34-enriched peripheral blood stem cells (PBSCs). Endothelial cells were grown in culture for 21-28 days and were characterized as CD31(+) CD14(-) via flow cytometry, as acLDL(+) UEA-1(+) via immunohistochemistry, and as Flk-1(+) by reverse transcriptase-polymerase chain reaction (RT-PCR). Animals had stable vector marking in hematopoietic lineages of 2-15%. Neither cultured circulating EPCs collected in steady state (n = 3), nor endothelial cells grown from large vessels (n = 2), had detectable retroviral marking. EPCs were CD34(+) and could be mobilized into the circulation with granulocyte colony-stimulating factor. Under ex vivo culture conditions, in which CD34(+) cells were optimized to transduce hematopoietic progenitor and stem cells, there was a marked depletion of EPCs. Transduction of EPCs was much more efficient under conditions supporting endothelial cell growth. Further elucidation of the origin and in vivo behavior of EPCs may be possible, using optimized transduction conditions and a vascular injury model.
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PMID:Analysis of origin and optimization of expansion and transduction of circulating peripheral blood endothelial progenitor cells in the rhesus macaque model. 1248 99

Platelet accumulation in glomerular capillaries (GC) and peritubular capillaries (PC) has pathogenetic importance in antibody-mediated hyperacute renal allograft rejection. CD61 is expressed constitutively by platelets, by platelet microparticles arising from platelet activation, and is readily detectable by immunohistochemistry. This study examined the immunohistochemical localization of CD61 in acute humoral rejection (AHR) of renal allografts to explore the relationship of platelet accumulation to antibody-mediated rejection. Two observers graded the extent of CD61 staining in PC and GC from 0 (none) to 2+ (>50%) in 15 renal allograft biopsy specimens with AHR and compared these with tissues from allografts with acute cellular rejection (ACR) (n = 23); acute calcineurin inhibitor toxicity (ACIT) (n = 21) with thrombotic microangiopathy (TMA) (n = 11) and tubular toxicity only (n = 10); acute tubular necrosis (ATN) (n = 16); acute renal vein thrombosis (RVT) (n = 4); and histologically unremarkable native kidneys (n = 26). Selected tissues were examined by electron microscopy and stained for CD34 by immunohistochemistry. Histologically unremarkable native kidney tissues had CD61 only in scattered small lumenal granules in GC and PC. Mural and occlusive lumenal CD61 deposits (>0.5+) were observed in 13 of 13 (100%) allograft tissues with GC thrombi due to AHR (1) and ACIT TMA (9) and RVT (3). Twenty-seven of 66 allografts (40.9%) without glomerular thrombi had >0.5+ GC CD61 in AHR (60%), ACR (26%), tubular ACIT (60%), and ATN (44%). More than trace (>0.5+) PC mural and lumenal CD61 deposits were seen only in AHR (53.3%) and ACR (30%). PC CD61 correlated with interstitial hemorrhage (r = 0.64), neutrophilic capillaritis (r = 0.47), and interstitial inflammation (r = 0.47) (P <0.001 for each). PC CD61 was observed in 11 of 11 foci of necrosis due to AHR, RVT, and ischemia. In AHR, capillaries with CD61 deposits had few platelets, numerous microvesicles and membrane fragments, severe endothelial injury seen on electron microscopy, and reduced capillary CD34 expression. CD61 detection by immunohistochemistry revealed products of capillary platelet activation in allograft biopsy specimens without light microscopic thrombi. Observations in this study suggest that intracapillary platelet activation occurs in response to graft capillary injury from many causes and may not be specific for antibody-mediated rejection.
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PMID:Platelets and capillary injury in acute humoral rejection of renal allografts. 1282 6

Endothelial progenitor cells (EPCs), which were first identified in adult peripheral blood mononuclear cells (MNCs), play an important role in postnatal neovascularization. Tissue ischemia augments mobilization of EPCs from bone marrow into the circulation and enhances incorporation of EPCs at sites of neovascularization. Two methods to obtain EPCs from bone marrow, peripheral blood or cord blood MNCs have been evaluated for therapeutic neovascularization: (1) fresh isolation using anti-CD34, anti-KDR or anti-AC133 antibody, and (2) ex vivo expansion of total MNCs. In an immunodeficient mouse model of hindlimb ischemia, systemic transplantation of human ex vivo expanded EPCs improves limb survival through the enhancement of blood flow in the ischemic tissue. A similar strategy also leads to histological and functional preservation of ischemic myocardium of nude rats. Recently, a preclinical study of catheter-based, intramyocardial transplantation ofautologous EPCs in a swine model of chronic myocardial ischemia demonstrated the therapeutic potential of cell-based therapy, with attenuation of myocardial ischemia and improvement in left ventricular function. These favorable outcomes strongly suggest a therapeutic impact of EPC transplantation in clinical settings. Further basic research, with improved understanding of the mechanisms governing homing and incorporation of EPCs, will be still necessary to optimize the methodology of the cell therapy.
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PMID:Transplantation of endothelial progenitor cells for therapeutic neovascularization. 1297 78

An 85-yr-old male presented with complaints of a 40-lb weight loss and a dull left upper quadrant abdominal pain. He also complained of decreased appetite, generalized weakness, generally not feeling well, and a dull left upper quadrant abdominal pain that was not relieved by food. He had a ventral and a left-sided inguinal hernia. Laboratory investigations revealed iron deficiency anemia, the cause of which was not apparent despite extensive investigation including computerized tomographic scans, esophagogastroduodenoscopy, and small-bowel follow-through examination. Surgical exploration for possible angiodysplasia, malignancy, and/or mesenteric ischemia revealed an incarcerated hernia, and the histopathological examination of the surgical specimen revealed high-grade angiosarcoma. The tumor showed strong positivity for vimentin and CD31 and a focal positivity for Factor VIII and CD34. At that time he was found to have hepatic metastases. He was started on thalidomide as an experimental measure with no change in the performance status and increasing evidence of necrosis in the metastatic lesion.
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PMID:Angiosarcoma of the small intestine: a possible role for thalidomide? 1471 38


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