Significance Of Angiogenesis Research Articles

Differentiation of endothelial proginetor cells from canine peripheral blood mononuclear cells

Background: Endothelial cell differentiation from peripheral blood or bone marrow cells is of great significance in angiogenesis, vascular healing, and tissue engineering. The purpose of this study was to characterize endothelial cell morphology, gene expression, and growth curve of endothelial progenitor cells (PEC) differentiated from canine peripheral blood mononuclear cells (PBMCs). Methods: PBMCs were isolated from fresh dog blood by Hitopaque-1077. Cells were cultured in fibronectin coated plates with endothelial basic medium (EBM-2) for different periods of time. PECs were identified from cell morphology and outgrowth characteristics. Gene expression was studied with flow cytometry analysis. Cell counting technique was used to study cell growth curve of PECs in comparison with primary human coronary artery endothelial cells. Results: At first week of canine PBMC culture, cells were round and many cells died every day. The cell proliferation was very low. At 2 weeks, many cells became spindle shape, showing endothelial morphology. At 3 weeks, many colonies of PECs with cobblestone morphology showed outgrowth. Canine PECs had great growth potential and reached a monolayer in a few days. They formed tight junctions, and showed endothelium like characteristics. Cell markers were studied at 25 days of culture. CD34 was significantly decreased compared to 7 days culture (54% to 6.27%). vWF was significantly increased (from 8.2% to 58.55%). CD31 was not changed. VEGF-R2 was slightly increased. Endothelial nitric oxide synthase was significantly increased (from 0 to 14.97%). Canine PECs showed a significant higher proliferation rate as compared to mature human coronary artery endothelial cells at the same culture condition. Conclusions: These data demonstrate that canine PBMCs are able to differentiate into PECs with characteristics of endothelial morphology and cell specific markers, and canine PECs have a greater growth potential than mature endothelial cells. This study suggests that PBMCs could be a source of PECs, which have potential applications in tissue engineering and vascular therapy.

Increased angiogenesis in the bone marrow of HIV-positive patients with myelodysplasia

<h2>Summary</h2><h3>Aim</h3> Little is known about the significance of angiogenesis in the bone marrow of HIV-positive patients with myelodys-plastic features (MDF). However, this process has been associated with the pathogenesis of primary myelodysplastic syndromes (MDS). The aim of the study was to investigate angiogenesis in the bone marrow of HIV-positive patients. <h3>Methods</h3> Bone marrow biopsies from 28 HIV-positive patients were immunostained for factor VIII and the micro-vessel density (MVD) was quantitatively evaluated and compared with that of 32 biopsies from patients with primary MDS and to 18 control bone marrows from patients with no evidence of bone marrow disease. <h3>Results</h3> Bone marrow MVD in HIV-positive patients was similar to that of MDS. However, both groups revealed significantly higher MVD counts compared to those of control bone marrows (MDF vs controls <i>P</i>=0.022, MDS vs controls <i>P</i>=0.001). <h3>Conclusions</h3> Bone marrow from HIV-positive patients with MDF reveals similar microvessel counts compared to those with primary MDS, although both differ significantly from that of control bone marrow. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients, may provide further insights into the pathobiology of AIDS and might be of value for the development of new therapeutic strategies for this disease.

Increased angiogenesis in the bone marrow of HIV-positive patients with myelodysplasia

Little is known about the significance of angiogenesis in the bone marrow of HIV-positive patients with myelodysplastic features (MDF). However, this process has been associated with the pathogenesis of primary myelodysplastic syndromes (MDS). The aim of the study was to investigate angiogenesis in the bone marrow of HIV-positive patients. Bone marrow biopsies from 28 HIV-positive patients were immunostained for factor VIII and the microvessel density (MVD) was quantitatively evaluated and compared with that of 32 biopsies from patients with primary MDS and to 18 control bone marrows from patients with no evidence of bone marrow disease. Bone marrow MVD in HIV-positive patients was similar to that of MDS. However, both groups revealed significantly higher MVD counts compared to those of control bone marrows (MDF vs controls P=0.022, MDS vs controls P=0.001). Bone marrow from HIV-positive patients with MDF reveals similar microvessel counts compared to those with primary MDS, although both differ significantly from that of control bone marrow. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients, may provide further insights into the pathobiology of AIDS and might be of value for the development of new therapeutic strategies for this disease.

The Molecular Biology of Peritoneal Carcinomatosis from Gastrointestinal Cancer

Introduction: Peritoneal carcinomatosis is a frequent form of disease progression in gastrointestinal cancer, and all too often is a preterminal event with a median survival of only 6 months. Despite the introduction of aggressive surgical and chemotherapeutic approaches, any significant improvement in survival is unlikely until we better understand the molecular biology of peritoneal metastasis. Methods: A Medline search and review of references was undertaken to identify all manuscripts in the English language concerned with peritoneal metastasis from gastrointestinal cancer. Results: Peritoneal carcinomatosis involves a complex sequence of interdependent steps. The injured peritoneum is a rich source of cytokines and growth factors that facilitate tumour proliferation and invasion in the postoperative abdomen. Peritoneal tumour adhesion is dependent on adhesion molecules, such as CD44, and the ß-1 integrins. Invasion of the mesothelium involves, at least in part, a process of tumour-induced mesothelial apoptosis. Matrix metalloproteinases, such MMP-7, facilitate stromal invasion, but the role of other proteases ininvasion remains to be elucidated. To date, the significance of angiogenesis in the peritoneal metastatic cascade is unknown. Conclusion: The molecular biology of peritoneal carcinomatosis is only just beginning to be understood. Further research into the mediators of the peritoneal metastatic cascade is needed if more effective therapeutic strategies are to be developed for this invariably fatal, yet unfortunately common, condition.

Significance of angiogenesis in cancer therapy.

For most solid tumours, surgery remains the most effective primary treatment. Despite apparently curative resection, significant numbers of patients develop secondary disease due to growth of undetected micrometastases. The ability of a tumour to metastasize is related to the degree of angiogenesis it induces. In addition, micrometastases rely on new vessel formation to provide the nutrients necessary for growth. A better understanding of how tumours acquire their blood supply may lead to more effective adjuvant therapies and improve survival following surgery. A systematic review of the literature on angiogenesis between 1971 and 1997 was performed using the Medline database to ascertain current thinking on angiogenesis and its relevance in oncological surgery. Angiogenesis is a physiological process subject to autocrine and paracrine regulation which has the potential to become abnormal and play a part in a number of pathological states, including cancer. Increased angiogenic stimuli in the perioperative period, associated with concomitant reduction in tumour-derived antiangiogenic factors following resection of a primary tumour, result in a permissive environment which allows micrometastases to grow. Recognition of the role of angiogenesis in metastatic tumour growth represents a significant development in our understanding of tumour biology. The development of antiangiogenic agents offers new promise in the treatment of malignancy. Such agents may prevent or control the development and growth of primary and metastatic tumours.

Molecular mechanisms of tumor angiogenesis.

The maintenance of growth of malignant tumors is closely related with the development of the vascular network supplying the tumor with blood. The vascularization of tumor tissue is similar to physiological angiogenesis, but in tumors it has some specific features. During the last 25 years a vast number of biomolecules have been found and described which are involved in the regulation of tumor angiogenesis. This review considers the action mechanisms and specific features of expression of the main angiogenic growth factors, such as the vascular endothelium growth factor (VEGF), angiopoietins (Ang-1, Ang-2), and the basic fibroblast growth factor (bFGF). The roles of cytokines, growth factors, proteolytic enzymes, and cell adhesion molecules in the regulation of the key steps of blood vessel generation in the tumor are considered. The significance of angiogenesis in the treatment of oncological diseases and possible approaches for inhibition of the regulatory signals of angiogenic factors are discussed.

Significance of angiogenesis and microvascular invasion in renal cell carcinoma.

The aim of this study is to evaluate the relationship between tumor angiogenesis and microvascular invasion, and the subsequent development of metastatic disease in patients undergoing surgery for renal cell carcinoma (RCC). The study group consisted of 102 patients who underwent surgery for RCC between the years 1990 and 1997 in our institute with a mean follow up period of 81.3 months. Paraffin blocks were stained for Factor VIII - related antigen and CD34 which decorate endothelial cells in order to assess angiogenesis and microvascular invasion and their relevance for developing metastatic disease. When Factor VIII- related antigen staining was used we found that the microvessel count correlated with the development of metastatic disease with a mean count of 49.7 for patients with no evidence of disease and a mean count of 95.5 for patients who developed metastatic disease (p<0.05). We also found that microvascular invasion correlated with the development of metastatic disease. It was demonstrated in 55.5% of patients who developed metastatic disease versus 23.8% of patients with no evidence of disease with Factor VIII staining (p<0.05), and in 33.3% and 7.1%, respectively (p<0.05) with CD34 staining. This study suggest that demonstration of intense angiogenesis and micro-vascular invasion may be a predictor of a more aggressive tumor mandating closer follow up and consideration of adjuvant therapy.

Clinical significance of angiogenesis in rectal carcinoid tumors

This study was designed to examine angiogenesis in rectal carcinoid tumors in relation to the clinicopathologic features. Seventy-seven rectal carcinoid tumors were studied clinicopathologically and experimentally. Cellular proliferation and microvessel density (MVD) were examined immunohistochemically. We used the antibodies MIB-1 for Ki-67, DO7 for p53, and NU-4A1 for CD34 expression in this study. Ki-67 labeling index (LI) of all lesions was below 3%, and the median Ki-67 LI of all lesions was 0.68+/-0.70% (mean +/- SD). A correlation was recognized between tumor size, metastasis and Ki-67 LI (p<0.05). Median MVD of all lesions was 25.9+/-13.1 (mean +/- SD). MVD was correlated with the tumor size (p<0.01), presence of depression (p<0.01), lymphatic (p<0.01) or venous (p<0.05) invasion, and existence of metastasis (p<0.01). But there was no significant relationship between MVD and Ki-67 LI. p53 protein was detected sporadically in only 1 case (1.3%) demonstrating both liver and lymph node metastases. Rectal carcinoid tumors are slow-growing tumors with a lower proliferative activity. Angiogenesis plays an important role in progression of rectal carcinoid tumors independent of the cellular proliferative activity.

Coexpression of vascular endothelial growth factor and p53 protein in squamous cell carcinoma of the esophagus

OBJECTIVE: p53 plays a role in tumor angiogenesis, and vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The aim of the present study was to clarify how expression of p53 protein participates in angiogenesis, and whether the coexpression of VEGF and p53 protein has a significance for angiogenesis and the clinicopathological features in esophageal squamous cell carcinoma (SCC). METHODS: Tissues samples were taken from 60 patients with esophageal SCC after surgery. The expression of VEGF and p53 protein in these SCC was examined immunohistochemically. Microvessel density (MVD) was determined by counting microvessels in tumor sections stained for Factor VIII-related antigen. Ki-67 labeling index (LI) was calculated, based on Ki-67 antigen immunostaining, as a proliferative marker. Apoptotic index (AI) was calculated, based on the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling, to evaluate apoptosis. RESULTS: VEGF expression was observed in 58.3%, and p53 protein expression was observed in 61.7% of the 60 patients. VEGF and p53 protein were significantly coexpressed in 26 (43.4%). Histological venous invasion ( p < 0.01) and distant metastasis ( p < 0.05) were significantly correlated with p53 protein expression. The two parameters were more frequently observed in the SCC with VEGF/p53 coexpression than in those without the coexpression. The MVD and Ki-67 LI were significantly higher ( p < 0.01 and p < 0.001), and the AI was significantly lower ( p < 0.001) in the SCC with p53 protein expression than in the SCC without it. The MVD and Ki-67 LI were higher, and the AI was lower in the SCC with VEGF/p53 coexpression than in those without the coexpression. The 5-yr survival rate in patients with the coexpression was poorer than in the other patients. CONCLUSION: These results suggest that mutant p53 expression is associated with angiogenesis and distant metastasis in esophageal SCC, and that the coexpression of p53 and VEGF may play an important role in angiogenesis, and have important clinical significance.

Coexpression of vascular endothelial growth factor and p53 protein in squamous cell carcinoma of the esophagus.

p53 plays a role in tumor angiogenesis, and vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The aim of the present study was to clarify how expression of p53 protein participates in angiogenesis, and whether the coexpression of VEGF and p53 protein has a significance for angiogenesis and the clinicopathological features in esophageal squamous cell carcinoma (SCC). Tissues samples were taken from 60 patients with esophageal SCC after surgery. The expression of VEGF and p53 protein in these SCC was examined immunohistochemically. Microvessel density (MVD) was determined by counting microvessels in tumor sections stained for Factor VIII-related antigen. Ki-67 labeling index (LI) was calculated, based on Ki-67 antigen immunostaining, as a proliferative marker. Apoptotic index (AI) was calculated, based on the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling, to evaluate apoptosis. VEGF expression was observed in 58.3%, and p53 protein expression was observed in 61.7% of the 60 patients. VEGF and p53 protein were significantly coexpressed in 26 (43.4%). Histological venous invasion (p < 0.01) and distant metastasis (p < 0.05) were significantly correlated with p53 protein expression. The two parameters were more frequently observed in the SCC with VEGF/p53 coexpression than in those without the coexpression. The MVD and Ki-67 LI were significantly higher (p < 0.01 and p < 0.001), and the AI was significantly lower (p < 0.001) in the SCC with p53 protein expression than in the SCC without it. The MVD and Ki-67 LI were higher, and the AI was lower in the SCC with VEGF/p53 coexpression than in those without the coexpression. The 5-yr survival rate in patients with the coexpression was poorer than in the other patients. These results suggest that mutant p53 expression is associated with angiogenesis and distant metastasis in esophageal SCC, and that the coexpression of p53 and VEGF may play an important role in angiogenesis, and have important clinical significance.

Prognostic significance of angiogenesis in non-small cell lung cancer

Background : Angiogenesis plays a critical role in human tumor growth and metastasis. Microvessel count as a measure of tumor angiogenesis, has been significantly correlated with invasive and metastatic patterns in breast. prostate and cutaneous carcinomas. Materials and Methods : Fifty patients with curatively resected non-small cell lung cancer were evaluated. Tumor tissues embedded in paraffin block were stained by anti CD 31 (PECAM, platelet endothelial cellular adhesion molecule) using immunohistochemical method to assess microvessel count. Microvessels were counted in the most active areas of neovascularization(microscopy, 200). Results: 1) Mean microvessel count was 47.117.7(per 200field) in total 50 cases. 2) Mean microvessel count of adenocarcinoma (54.419.9) was significantly higher than that of squamous cancer (43.916.2) (p45, 28 cases) were 46 months, 75% and 12%, respectively. As results, prognosis of low microvascular group is statistically significantly superior to that of the high microvascular group (p=0.0162, Kaplan-Meier, log-rank). Conclusion : Angiogenesis assessed by microvessel count can be used as one of the significant prognostic factors in non-small cell lung cancer.

Prognostic significance of angiogenesis in squamous cell carcinoma of the larynx

Prognostic significance of angiogenesis in squamous cell carcinoma of the larynx

Lack of prognostic significance of angiogenesis in non-small-cell lung carcinoma

Lack of prognostic significance of angiogenesis in non-small-cell lung carcinoma

Comparative 3d-Morphometry of the Microvascular Unit In Tumors and Normal Tissues: Quantitative Studies on Corrosion Casts

Abstract The significance of angiogenesis and the vascular architecture have been stressed in numerous studies of the structure and biological properties of the tumor vasculature and blood flow (Folkman and D'Amore, 1996; Jain, 1988). The important question as to whether the vascular architecture of an individual tumor is tumor type specific has been controversial. This is due, at least in part, to the methodologies used. Most reports confine themselves to qualitative observations and comparisons of gross vascular patterns in host and tumor, or to blood vessel density, length and diameter measurements, which in turn vary with the staining and counting techniques. We studied the microvascular architecture of four different tumor cell lines (CaX, CaNT, SaS, HEC- 1B) in order to determine whether there is a characteristic vascular pattern for different tumor types and whether it differs significantly from two normal tissues, muscle and gut.

Angiogenesis during tumor progression in the oral cavity is related to reduced apoptosis and high tumor cell proliferation.

Angiogenesis, the growth of new blood vessels, is believed to aid tumor progression and metastasis. Tumor progression is also influenced by the extent of proliferation and apoptosis. This study, therefore, analyzed in lesions of the oral cavity, the significance of angiogenesis in relation to apoptosis, expression of apoptosis regulatory p53, bax and bcl-2 proteins as well as tissue proliferation defined by cyclin D1 expression. Results from this study suggest that angiogenesis increases as histological abnormality increases in the oral mucosa. The expression of apoptosis regulatory proteins also appears to be altered in a histologically dependent manner. The correlation seen between CD34 expression, cyclin D1 and TUNEL reactive cells suggests that increased angiogenesis, decreased apoptosis and deregulated proliferation occur simultaneously during tumor progression in the oral mucosa. Presence of a mutant p53, increased bcl-2 expression and altered bax expression are also involved in this complex process.

Prognostic Significance of Angiogenesis in Transitional Cell Carcinoma of the Human Urinary Bladder

OBJECTIVES To quantify tumour angiogenesis in bladder cancer and determine whether it correlates with tumour stage, grade and survival. PATIENTS AND METHODS Archival samples from a total of 113 patients newly presenting with transitional cell carcinomas of the urinary bladder were graded and staged, and analysed for angiogenic blood vessel density by a double immunohistochemical technique. The findings were correlated with the information obtained during a minimum follow-up of 12 years. RESULTS Univariate analysis showed that TNM stage (P = 0.02) and mean vessel count (P = 0.01) were significant predictors of death from bladder cancer. Blood vessel density was significantly correlated with tumour stage (P = 0.01) and the presence of vascular invasion (P = 0.007). Trained observers were essential for the accurate counting of blood vessels to prevent excessive inter-observer variability. Multiple regression analysis showed that the combination of mean vessel count and stage was a significant prognostic indicator. CONCLUSION Angiogenesis in primary bladder cancer is a predictor of death from the disease. Further work to determine whether it predicts invasion and recurrences in superficial tumours may be valuable.

Angiogenesis in esophageal squamous cell carcinoma.

We retrospectively analyzed the prognostic significance of angiogenesis and the relationships between tumor angiogenesis and clinopathological variables in a series of 127 patients with primary esophageal squamous cell carcinoma which were curatively resected. Vessels were stained with anti-factor VIII polyclonal antibody and areas with the highest number of microvessels were counted in a x400 field. Microvessel counts were significantly correlated with pN category, pM category, venous invasion and recurrence (p=0.002, p=0.040, p=0.016 and p=0.0013, respectively). The proportion of patients with recurrence increased in proportion to the number of microvessels. multivariate analysis using Cox's proportional hazard modelling showed angiogenesis assessed by microvessel count affected the poorer prognosis of patients with esophageal squamous cell carcinoma (hazard ratio, 1.03; 95%CI, 1.00-1.07), although it was not a significant independent prognostic factor (P=0.088). This study suggest that angiogenesis assessed by microvessel count is a marker for relapse and prognosis in patients with esophageal squamous cell carcinoma.

The significance of angiogenesis in guided bone regeneration. A case report of a rabbit experiment.

A dome-shaped bioresorbable membrane was fixed to the wounded rabbit calvaria and filled with a bioresorbable fibre conglomerate. After 4 weeks, the histologic preparation revealed an intimate spatial and temporal correlation between newly formed blood vessels and de novo extraskeletal bone formation. These observations emphasize the significance of angiogenesis in guided bone generation.

Clinicopathologic study of angiogenesis in Japanese patients with breast cancer.

To evaluate the clinicopathologic significance of angiogenesis as a prognostic factor and the objective methods for evaluating angiogenesis, we immunohistochemically stained a representative section of breast tumors with factor VIII-related antigen staining. There were 109 patients with primary breast cancer from 1971 to 1979. The two methods of identifying angiogenesis were the average microvessel count per square millimeter (AMC) and the highest microvessel count per square millimeter (HMC). There was no relation between microvessel count (AMC or HMC) or age, menopausal status, clinical tumor size (T), histologic classification, nuclear grade, node status, histologic grade (HG), mitosis index, or lymphatic invasion (LI). There was a relation between microvessel count and blood vessel invasion (BVI) (HMC:p = 0.0007) and tumor necrosis (TN) (HMC:p = 0.0050). Univariate analysis showed that AMC or HMC was a statistically significant predictor of overall survival in all patients (p = 0.0086 and p = 0.0307, respectively). Multivariate analysis showed that AMC was an independent predictor of node status when we fitted a model with node status, BVI, and either AMC or HMC; but HMC was not independent. However, when we fitted a model including all 11 of the other indicators and AMC or HMC, the node status, HG, and LI were independent predictors, but AMC and HMC were not. Although AMC was a better method than HMC for evaluating angiogenesis, we cannot confirm angiogenesis as a significant independent prognostic factor associated with long-term survival in Japanese breast cancer patients.

Significance of angiogenesis in tumour progression and metastasis.

Angiogenesis is defined as a vascular neoformation usually of capillary origin. This phenomenon is important during development and under several physiological and or pathological conditions. In recent years, progress has been made to understand this phenomenon at the molecular level. This includes the identification of potent angiogenic factors, the appreciation of the role of proteases, the importance of the extracellular matrix, and the emerging characterisation of signal transduction pathways in endothelial cells. Two important participants in angiogenesis are molecules from the fibroblast growth factor (FGF) and the transforming growth factor-beta (TGF-beta) family. In our laboratory, we have extensively studied the roles and mechanisms of action of the major FGF prototype, FGF-2 and of the TGF-beta member, TGF-beta 1. Different isoforms of FGF-2 have been previously described, a high molecular weight (HMW) form associated with the nucleus and 18 kDa bFGF that is cytoplasmic. These two forms of FGF-2 also exhibit different functions when expressed endogenously. TGF-beta is formed from a latent complex by plasmin-dependent and plasmin-independent pathways. With the exception of macrophages, the plasmin-dependent pathway requires coculture conditions, urokinase, and the concentration of TGF-beta on the cell surface by the mannose-6-phosphate receptor and transglutaminase. Other important angiogenic modulators include vascular endothelial growth factor (VEGF) and angiostatin. The nature of the tumour angiogenesis factor is not yet known with certainty, but several identified and not yet identified angiogenic factors may act in concert. It is hoped that an angiostatic treatment for cancer will be derived from these molecular studies.