			Home About us Contact

Vascular Density (vascular + density)

Distribution by Scientific Domains

Medical Sciences	80%
Life Sciences	20%

Distribution within Medical Sciences

Immunology	32%
Urology	25%

Selected Abstracts

Human First-Trimester Decidua Vascular Density: An Immunohistochemical Study Using VE-Cadherin and Endoglin as Endothelial Cell Markers

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2000
BRUNO VAILHÉ
PROBLEM: Angiogenesis and vasculogenesis appear to be of critical importance for the success of pregnancy. Recent data have emphasized that pregnancy complications, such as abortion or pre-eclampsia, are linked with vascular pathologies. The aim of this study was to quantify human first-trimester decidua microvascular density, using two novel, highly specific endothelial cell markers, VE-cadherin and endoglin. METHOD OF STUDY: We collected decidua from women undergoing termination of normal pregnancies. VE-cadherin and endoglin were localized by immunohistochemistry. The blood vessel densities detected by VE-cadherin or endoglin-stainings were microscopically quantified per mm2. RESULTS: Endothelial cells in first-trimester human decidua both express VE-cadherin and endoglin. The microvascular density detected by VE-cadherin-staining varied from 32.2±1.7 in decidua basalis, to 30±0.6 in decidua parietalis. For the endoglin-staining, the values varied from 37.5±3 in decidua basalis, and 26.7±1.2 in decidua parietalis. CONCLUSIONS: Our data shows that both VE-cadherin and endoglin are good candidates to highlight the decidual endothelial cells, and to quantify the blood vessels density of endometrium. [source]

Bone vascular supply in monitor lizards (Squamata: Varanidae): Influence of size, growth, and phylogeny

JOURNAL OF MORPHOLOGY, Issue 5 2008
Vivian de Buffrénil
Abstract Bone vascular canals occur irregularly in tetrapods; however, the reason why a species has or lacks bone canals remains poorly understood. Basically, this feature could depend on phylogenetic history, or result from diverse causes, especially cortical accretion rate. The Varanidae, a monophyletic clade that includes species with impressive size differences but similar morphologies, is an excellent model for this question. Cortical vascularization was studied in 20 monitor species, on three bones (femur, fibula, and tibia) that differ in their shaft diameters, and in the absolute growth speed of their diaphyseal cortices. In all species smaller than 398 mm SVL (133,397 mm in sample), bone cortices lack vascular canals, whereas all larger species (460,1,170 mm in sample) display canals. The size 398,460 mm SVL is thus a threshold for the appearance of the canals. The distribution of vascular and avascular bone tissues among species does not precisely reflect phylogenetic relationships. When present, vascular canals always occur in the femur and tibia, but are less frequent, sparser, and thinner in the fibula. Vascular density increases linearly with specific size but decreases exponentially during individual growth. In most species, canal orientation varies between individuals and is diverse in a single section. No clear relationship exists between canal orientation and vascular density. These results suggest that: a) the occurrence and density of bone vascular canals are basically dependant on specific size, not phylogenetic relationships; b) vascular density reflects the absolute growth rates of bone cortices; c) the orientation of vascular canals is a variable feature independent of phylogeny or growth rate. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source]

Association between blood flow and inflammatory state in a T-cell transfer model of inflammatory bowel disease in mice

INFLAMMATORY BOWEL DISEASES, Issue 5 2010
Norman R. Harris PhD
Abstract Background: Adoptive transfer of naive T-lymphocyte subsets into lymphopenic mice initiates chronic gut inflammation that mimics several aspects of inflammatory bowel disease (IBD). Patients with IBD can have profound alterations in intestinal blood flow, but whether the same is true in the T-cell transfer model has yet to be determined. Methods: In the current study, chronic intestinal inflammation was induced in recombinase-activating gene-1-deficient (RAG,/,) mice by adoptive transfer of CD4+ T-lymphocytes obtained from interleukin-10 deficient (IL-10,/,) mice. Results: Four weeks later, widespread colonic inflammation was observed in the reconstituted recipients, in contrast to 2 control sets of mice injected with a different subset of lymphocytes or with vehicle alone. We observed that the resulting pathology induced in the reconstituted RAG,/, mice was divided distinctly into 2 subsets: 1 with blood flow near normal with very high inflammation scores, and the other with severely attenuated blood flow but with much lower signs of inflammation. Colonic and ileal blood flow rates in the latter subset of CD4+ mice averaged only ,30% compared to the mice with higher inflammation scores. The lower blood flow rates were associated with greatly reduced red blood cell concentrations in the tissue, suggesting a possible loss of vascular density. Conclusions: In this model of chronic intestinal inflammation, mild inflammation was associated with significant decreases in blood flow. Inflamm Bowel Dis 2009 [source]

Bone vascular supply in monitor lizards (Squamata: Varanidae): Influence of size, growth, and phylogeny

Femur window,a new approach to microcirculation of living bone in situ

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2005
N. Hansen-Algenstaedt
Abstract Background: The processes of osteogenesis, bone remodelling, fracture repair and metastasis to bone are determined by complex sequential interactions involving cellular and microcirculatory parameters. Consequently studies targeting the analysis of microcirculatory parameters on such processes should mostly respect these complex conditions. However these conditions could not yet be achieved in vitro and therefore techniques that allow a long-term observation of functional and structural parameters of microcirculation in bone in vivo at a high spatial resolution are needed to monitor dynamic events, such as fracture healing, bone remodelling and tumor metastasis. Methods: We developed a bone chamber implant (femur window) for long-term intravital microscopy of pre-existing bone and its microcirculation at an orthotopic site in mice preserving the mechanical properties of bone. After bone chamber implantation vascular density, vessel diameter, vessel perfusion, vascular permeability and leukocyte-endothelial interactions (LEIs) in femoral bone tissue of c57-black mice (n = 11) were measured quantitatively over 12 days using intravital fluorescence microscopy. Furthermore a model for bone defect healing and bone metastasis in the femur window was tested. Results: Microvascular permeability and LEIs showed initially high values after chamber implantation followed by a significant decrease to a steady state at day 6 and 12, whereas structural parameters remained unaltered. Bone defect healing and tumor growth was observed over 12 and 90 days respectively. Conclusion: The new femur window design allows a long-term analysis of structural and functional properties of bone and its microcirculation quantitatively at a high spatial resolution. Altered functional parameters of microcirculation after surgical procedures and their time dependent return to a steady state underline the necessity of long-term observations to achieve unaltered microcirculatory parameters. Dissection of the complex interactions between bone and microcirculation enables us to evaluate physiological and pathological processes of bone and may give new insights especially in dynamic events e.g. fracture healing, bone remodeling and tumor metastasis. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

Inhibition of Canonical Wnt Signaling Increases Microvascular Hemorrhaging and Venular Remodeling in Adult Rats

MICROCIRCULATION, Issue 5 2010
JASON T. GLAW
Microcirculation (2010) 17, 348,357. doi: 10.1111/j.1549-8719.2010.00036.x Abstract Objective:, The canonical Wnt signaling pathway, heavily studied in development and cancer, has recently been implicated in microvascular growth with the use of developmental and in vitro models. To date, however, no study exists showing the effects of perturbing the canonical Wnt pathway in a complete microvascular network undergoing physiological remodeling in vivo. Our objective was to investigate the effects of canonical Wnt inhibition on the microvascular remodeling of adult rats. Methods:, Canonical Wnt inhibitor DKK-1, Wnt inhibitor sFRP-1, BSA or saline was superfused onto the exteriorized mesenteric windows of 300 g adult female Sprague-Dawley rats for 20 minutes. Three days following surgery, mesenteric windows were imaged intravitally and harvested for immunofluorescence staining with smooth muscle alpha-actin and BRDU. Results:, We observed prominent differences in the response of the mesenteric microvasculature amongst the various treatment groups. Significant increases in hemorrhage area, vascular density, and draining vessel diameter were observed in windows treated with Wnt inhibitors as compared to control-treated windows. Additionally, confocal imaging analysis showed significant increases in proliferating cells as well as evidence of proliferating smooth muscle cells along venules. Conclusions:, Together, our results suggest that canonical Wnt inhibition plays an important role in microvascular remodeling, specifically venular remodeling. [source]

Arteriolar Remodeling Following Ischemic Injury Extends from Capillary to Large Arteriole in the Microcirculation

MICROCIRCULATION, Issue 5 2008
Alexander M. Bailey
ABSTRACT Objective: Skeletal muscle vasculature undergoes arteriogenesis to restore tissue perfusion and function following loss of blood flow. This process has been shown to occur in large vessels following ischemia, although recent studies suggest this may occur in the microcirculation as well. We tested the hypothesis that ischemia induces microvascular remodeling in the skeletal muscle microcirculation on the scale of capillary to sub-35 ,m diameter arterioles. Methods: Ligations of a feeding arteriole to the caudal-half of the spinotrapezius muscle were performed on C57BL/6 mice. At 5 days, microvascular remodeling responses were quantified using intravital and whole-mount confocal microscopy. Immunohistochemistry was performed to visualize vessels, incorporated leukocytes, and regions of hypoxia. Results: Ischemic tissue underwent localized microvascular remodeling characteristic of arteriogenesis, including pronounced vessel tortuosity. In patent microvessels (diameters 15,35 ,m), we observed increases in vascular density (38%), branching (90%) and collateral development (36.5%). The formation of new arterioles (diameters 6,35 ,m) increased by 24.3%, while chronic hypoxia was absent from all tissues. Conclusions: Ischemic injury induces arteriogenesis in skeletal muscle microcirculation. Furthermore, this surgical model enables en face analysis of microcirculatory adaptations with single-cell resolution and can provide investigators with morphometric data on a microscale that is difficult to achieve using other models. [source]

Expression of Endothelial Cell Adhesion Molecules in Neovascularized Tissue

MICROCIRCULATION, Issue 4 2000
GINA VALLIEN
ABSTRACT Objective: Recent studies indicate that endothelial cells of newly formed blood vessels are activated and exhibit a distinct phenotype that may influence the responses of these microvessels to an inflammatory stimulus. The objective of this study was to compare the basal and cytokine-stimulated expression of endothelial cell adhesion molecules in neovascularized tissue to normal (nonproliferating) vascular beds. Methods: The expression of P- and E-selectin, VCAM-1, ICAM-1, ICAM-2, and PECAM-1 was measured, using the dual radiolabeled mAb technique, in subcutaneously implanted (for 10,15 days) polyurethane sponges, skin, heart, lung, and intestine of male C57BL/6 mice (background). Results: Basal values of PECAM-1 and ICAM-2 revealed a low vascular density in the implanted sponge matrices that is comparable to skin. When normalized for vascular surface area (PECAM-1 or ICAM-1 expression), the basal level of E- and P-selectin expression was highest in neovascularized sponge and skin. TNF-, elicited an increased expression of all endothelial CAMs, except PECAM-1 and ICAM-2, but the responses were blunted in sponge and skin, relative to other vascular beds. Conclusions: These findings indicate that endothelial cells in newly formed blood vessels exhibit a pattern of basal and cytokine-induced expression of certain adhesion glycoproteins that is similar to nonproliferating cutaneous vessels. [source]

Vascular endothelial growth factor and angiopoietin are required for prostate regeneration

THE PROSTATE, Issue 5 2007
Gui-min Wang
Abstract BACKGROUND The regulation of the prostate size by androgens may be partly the result of androgen effects on the prostatic vasculature. We examined the effect of changes in androgen levels on the expression of a variety of angiogenic factors in the mouse prostate and determined if vascular endothelial growth factor (VEGF)-A and the angiopoietins are involved in the vascular response to androgens. METHODS Expression of angiogenic factors in prostate was quantitated using real-time PCR at different times after castration and after administration of testosterone to castrated mice. Angiopoietins were localized in prostate by immunohistochemistry and in situ hybridization. The roles of VEGF and the angiopoietins in regeneration of the prostate were examined in mice inoculated with cells expressing soluble VEGF receptor-2 or soluble Tie-2. RESULTS Castration resulted in a decrease in VEGF-A, VEGF-B, VEGF-C, placenta growth factor, FGF-2, and FGF-8 expression after 1 day. In contrast, VEGF-D mRNA levels increased. No changes in angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), hepatocyte growth factor, VEGF receptor-1, VEGF receptor-2, or tie-2 mRNA levels were observed. Administration of testosterone to castrated mice had the opposite effect on expression of these angiogenic factors. Ang-2 was expressed predominately in prostate epithelial cells whereas Ang-1 was expressed in epithelium and smooth muscle. Inoculation of mice with cells expressing soluble VEGF receptor-2 or Tie-2 blocked the increase in vascular density normally observed after administration of testosterone to castrated mice. The soluble receptors also blocked the increase in prostate weight and proliferation of prostatic epithelial cells. CONCLUSION VEGF-A and angiopoietins are required for the vascular response to androgens and for the ability of the prostate to regenerate in response to androgens. Prostate 67: 485,499, 2007. © 2007 Wiley-Liss, Inc. [source]

Increased lymphatic vascular density is seen before colorectal cancers reach stage II and growth factor FGF-2 is downregulated in tumor tissue compared with normal mucosa

APMIS, Issue 3 2009
EIRIK SUNDLISÆTER
Lymphangiogenesis is an important event in progression of colorectal cancer (CRC), and the estimated lymphatic vascular density (LVD) probably indicates facilitated lymphatic tumor cell invasion and metastasis. However, at what time point during tumor progression this process is triggered, is unclear. The aim of this study was twofold. Firstly, to examine LVD in paired samples of CRC tissue and normal mucosa with specific emphasis on possible difference in LVD between tumors stages II and III, and secondly, the expression of the lymphangiogenic growth factor fibroblast growth factor-2 (FGF-2). Eighteen patients were studied. Immunostaining for podoplanin was performed to highlight lymphatic vessels. FGF-2 mRNA expression was determined by quantitative real-time RT-PCR, whereas protein expression was quantitatively assessed by densitometric analysis of Western blot signal intensity. The immunoblots were further validated by FGF-2 immunostaining of histological sections. LVD was significantly increased in tumor tissue compared with the normal mucosa but no changes in LVD between stages II and III CRC was observed. FGF-2 was found to be downregulated both at the mRNA and protein level in tumor tissues compared with normal mucosa. Lymphangiogenesis was triggered early in tumor development. An increased LVD was established before the tumor reached stage II. FGF-2 was downregulated in tumor tissue. The importance of this finding remains unclear. [source]

Vascularity in thyroid neoplasms: a methodological investigation with a view to diagnostics,

APMIS, Issue 11 2006
KAREN KJÆR LARSEN
The aim of the present study was to evaluate the reliability of four different methods (vascular grading, Chalkley count, microvessel density (MVD) and stereological estimation) for quantifying intratumoral microvascularity in thyroid neoplasms, by comparing the variability within and between observers. In addition, the diagnostic and prognostic potential of neovascularity expressed by the four methods was evaluated. The study had a retrospective design and involved 24 follicular adenomas (FA), 19 follicular carcinomas (FC), and 17 papillary carcinomas (PC). Chalkley count was reproducible both within and between observers. MVD was not reproducible. Within observer the reproducibility of vascular grading was substantial, between observers it was fair to moderate. Stereological estimation was a priori considered reproducible. Keeping time consumption, cost and reproducibility in mind, Chalkley count should be the preferred method for assessing microvascularity in thyroid neoplasms. The diagnostic evaluation revealed a tendency towards higher degree of vascularity in FA compared to both FC and PC for all methods. No statistically significant association was seen between vascular density and prognosis. [source]

A morphometric analysis of bulbar urethral strictures

BJU INTERNATIONAL, Issue 2 2007
Andre G. Cavalcanti
In a beautifully descriptive paper, authors from Rio de Janeiro and San Francisco report a quantitative and qualitative histological analysis of spongiosal tissue in patients with bulbar urethral strictures. They found that stricture formation was characterised by major alterations in extracellular matrix features. OBJECTIVE To report a quantitative and qualitative histological analysis of spongiosum tissue in patients with bulbar urethral strictures. MATERIALS AND METHODS Urethral specimens from 15 patients who had end-to-end anastomotic urethroplasty were evaluated; the control group comprised five bulbar urethras from cadavers. The collagen content, elastic fibres, smooth muscle and vessels were analysed using stereological methods. RESULTS There was complete loss of the relationship between smooth muscle, extracellular matrix and sinusoids in the peri-luminal area (PLA), with collagen replacement. The extension of the fibrotic area was greater in those with a traumatic than in those with an atraumatic stricture. The content of smooth muscle and collagen in the peripheral spongiosum (PS) area was similar for the stricture and control groups, and results were comparable for traumatic and atraumatic groups and those with suprapubic cystostomy diversion or not before surgery. There was a remarkably lower vascular density in the traumatic than in the atraumatic group. There was an increase in type III collagen in the PLA and in type I collagen in the PS; collagen type III in the PLA was greater in the group with no suprapubic cystostomy diversion before surgery. There were fewer elastic fibres in both stricture areas (PLA and PS) than in the control group. CONCLUSIONS Urethral stricture formation is characterized by marked changes in extracellular matrix features, with consequent changes in organ function. [source]

Prognostic significance of tumour angiogenesis in schistosoma-associated adenocarcinoma of the urinary bladder

BJU INTERNATIONAL, Issue 1 2002
E. El Sobky
Objective To report on tumour angiogenesis and its relationship with morphological variables and prognosis in adenocarcinoma of the urinary bladder associated with schistosomiasis. Patients and methods Fifty-five vesical adenocarcinomas were evaluated from 30 men and 25 women (mean age 47.2 years, sd 8.7, range 30,65) who were followed up after radical cystectomy and urinary diversion for a mean (sd, range) of 61 (43.5, 2.7,159.5) months. Vessels were stained immunohistochemically using an antibody to the platelet endothelial cell-adhesion molecule CD31. Microvessels were counted in active areas of angiogenesis within the tumours (at ×,250) and the microvessel density (MVD) quantified using the mean of three counts. Treatment failure was defined as death from cancer or the development of local recurrence or distant metastasis. Kaplan-Meier survival curves and Cox's proportional hazard model were used to assess survival. Results The overall 5- and 10-year survival rates were 57% and 51%, respectively. The presence of lymph node metastasis and high mean vascular density (> 26) were significantly associated with a poor prognosis. The 5-year survival for patients with negative lymph nodes was 66% while no patients with positive nodes survived for 5 years (P < 0.001); the survival was 72% for patients with a low MVD and 33% for those with a high MVD (P = 0.0016). From individual results plotted against vascularity in lymph node-negative patients, there was a significantly better outcome for those with a low MVD ( 26; P = 0.0099); this significance was maintained on multivariate analysis. However, there was no significant relationship between angiogenesis and the different clinicopathological factors apart from the grade (P = 0.03); tumour stage, grade and DNA profile had no significant effect on survival in these patients. Conclusions These findings suggest that assessing angiogenesis using the MVD provides an independent predictor of survival in patients with adenocarcinoma of the urinary bladder. [source]

Spleen neoangiogenesis in patients with myelofibrosis with myeloid metaplasia

BRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2004
Giovanni Barosi
Summary Neoangiogenesis is an integral component of bone marrow myeloproliferation in patients with myelofibrosis with myeloid metaplasia (MMM). As extramedullary haematopoiesis is a constitutive feature of MMM, we studied spleen neoangiogenesis by a computerized image analysis in MMM patients. Compared with five normal subjects, spleen CD34-staining capillary vascular density (CVD) was 2·1,3·03 times higher than the upper range of normal in six of the 15 (40%) MMM patients. CD8-staining sinusoidal vascular density (SVD) was constantly normal or lesser than normal and was inversely correlated with CVD (R = ,0·53; P = 0·04). In MMM patients who did not receive cytoreductive or radiation therapy in the month before splenectomy (n = 9), the CVD was a significant determinant of spleen size (R = 0·88; P = 0·04). In MMM patients, the number of spleen CD34+ haematopoietic stem cells was increased from 1·2 to 98 times the upper limit of normal, and predicted the expansion of CVD (R = 0·57; P = 0·03). A population of cells expressing the CD34+/CD133+/VEGFR-2+ angiopoietic phenotype was present in the blood and spleen of five of seven patients. These results document that neoangiogenesis is an integral component of spleen re-localization of haematopoietic stem cells and suggest a cellular mechanism for spleen neoangiogenesis. [source]