SEARCH · PubMed Health

Results for “Neovascularization, Pathologic”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82Linked to original sources

PubMed2004

The comparative study of tumor angiogenesis and CT enhancement in pancreatic carcinoma.

PURPOSE: The purpose of this work was to study the correlation of pancreatic phase Computed tomography (CT) enhancement, intratumoral microvessel density (MVD) and pathologic grades in pancreatic carcinoma and to evaluate the relationship between CT enhancement degree and the malignancy degree of pancreatic carcinoma. METHODS: 34 patients with pancreatic carcinoma underwent CT scanning before resection. The enhancement degrees and forms of tumor were observed in pancreatic phase. The operational sample was stained with HE and CD34 marked by immunohistochemistry. MVD and histopathological grades of pancreatic carcinoma were examined. CT enhancement of the tumor, MVD counting in hot spot areas of neoplastic parenchymal cells and pathological grades of pancreatic carcinoma were comparatively analyzed. RESULT: Highly differentiated pancreatic adenocarcinoma was identified in 16 patients, moderately differentiated tumor in seven and poorly differentiated tumor in 11. Isodensity CT enhancement was demonstrated in 13 cases, slight low density enhancement in nine, slight low density enhancement along with small cyst lesion in nine and slight low density enhancement along with large cyst lesion in three. The counting of MVD with CD34 marked by immunohistochemistry in hot spot areas of neoplastic parenchyma cells were small in ten cases, medium in 16 and large in eight. The pathological grades correlated with CT enhancement of tumor (r=0.7857, P<0.001). The pathological grade correlated with MVD counting of tumor (r=0.3613, P<0.05). The CT enhancement of tumor correlated with MVD (r=0.6768, P<0.001). CONCLUSION: There was obvious and significant correlation between CT enhancement, pathological grades and MVD numbers in the hot spot areas of tumor. The extent of CT enhancement was inversely proportional to the malignancy degree of pancreatic carcinoma, and inversely proportional to MVD numbers in the hot spot areas of neoplastic parenchyma. The MVD in the hot spot areas of neoplastic parenchyma cells could also reflect the prognosis of the patients, and was directly proportional to malignancy degree of pancreatic carcinoma.

Adenocarcinoma↗

PubMed2000

Association of preoperative radiation effect with tumor angiogenesis and vascular endothelial growth factor in oral squamous cell carcinoma.

This study examined the relationship between tumor angiogenesis and the radiation-induced response, evaluated based on pathological changes, in oral squamous cell carcinoma patients treated with preoperative radiation therapy. Forty-one cases of squamous cell carcinoma treated with preoperative radiation therapy were investigated. Tumor angiogenesis was assessed by scoring the intratumor microvessel density (IMVD). Expression of vascular endothelial growth factor (VEGF) was also evaluated before and after preoperative radiotherapy. There was no correlation between IMVD in the specimens before therapy and the pathological response to radiation therapy. However, radiation therapy decreased IMVD in the specimens after therapy. A significant association was observed between VEGF expression and resistance to radiation therapy: only 4 of the 21 patients whose tumors exhibited a high level (2 + or 3 + ) of VEGF staining experienced a major (3 + or 4 + ) pathological response to radiation therapy. Furthermore, an increasing level of VEGF expression after radiation therapy was observed in non-effective (0 to 2 + ) response cases. These results suggest that VEGF expression and the induction of this protein are related to radiosensitivity and could be used to predict the effects of preoperative radiation therapy on oral squamous cell carcinoma.

Adult↗

PubMed2003

Tumor angiogenesis: a potential target in cancer control by phytochemicals.

It is now well established that angiogenesis is an obligatory event for the growth and progression of solid tumors beyond the size limit (approximately 2 mm diameter) imposed by simple diffusion for the nutrient supply. Human tumors can remain dormant for years owing to a balance between cell proliferation and apoptosis. Several hypotheses have been articulated regarding the critical importance of tumor angiogenesis in the development and metastatic spread of tumors, and how preventive/therapeutic inhibition of angiogenesis might be exploited as a novel means of controlling cancer growth. Anti-angiogenic therapy is suggested as one of the most promising approaches to control cancer, as endothelial cells are generally non-transformed cells and are less prone to acquire drug resistance. Tumor vasculature could be an important prognostic marker, and an independent predictor of pathologic stages and malignant potential of cancer. This review is focused on recent developments and comprehensive mechanistic aspects of phytochemicals related to an interplay of angiogenic promoters and inhibitors, and associated signaling in both tumor as well as endothelial cells. Since, vascular endothelial cells constitute the first line exposure to the blood-borne agents, it is plausible that anti-angiogenic activity of phytochemicals could be associated with lowering the risk of cancer by preventing the growth and metastasis of tumor.

Angiogenesis Inhibitors↗

PubMed1999

Enhanced expression of Tie2, its ligand angiopoietin-1, vascular endothelial growth factor, and CD31 in human non-small cell lung carcinomas.

Expression of angiogenesis-associated genes was compared in 32 primary non-small cell lung carcinoma samples (14 adenocarcinomas, 17 squamous cell carcinomas, and 1 large cell carcinoma) and paired adjacent noncancerous lung tissues using a multiprobe RNase protection assay. Levels of Tie2, angiopoietin (Ang)-1, vascular endothelial growth factor (VEGF), and CD31 mRNAs were higher in cancers than in adjacent noncancerous tissues, in contrast to the fms-like tyrosine kinase (Flt)-1, Flt-4, Tie1, thrombin receptor, endoglin, and VEGF-C, for which no differences were evident. Overexpression did not seem to differ with histological type and pathological stage. Significant positive correlations were found between mRNA expression of Ang-1 and those of Tie2 and CD31, and that of VEGF and those of Flt-1 and CD31. These findings suggest that Ang-1 and VEGF are important angiogenic factors in human non-small cell lung carcinomas.

Adult↗

PubMedDate not supplied

Analysis of angiogenic profiles by estimation of tumor blood flow with colored dye extraction microspheres after antiangiogenic therapy.

No study has directly estimated tumor blood flow after antiangiogenic therapy. Using dye extraction colored microspheres, we estimated blood flow in a rat LY80 tumor model before and after antiangiogenic therapy with TNP-470. Dyed microspheres were infused into the tumor-bearing rats. The dye was extracted and its concentration was quantified by spectrophotometry. Tumor blood flow corrected for wet weight (ml. min(-1)g(-1)) was calculated as follows (AU = absorbency units): (blood flow to tumor) = (AU per gram of tumor) x (reference withdrawal rate)/(AU per gram of reference blood). Tumor tissues with or without TNP-470 were also examined histologically. Tumor blood flow 1 week after transplantation could be predicted by the simple regression equation. In the groups treated with TNP-470, this simple regression equation shifted to the left, despite virtually no difference in the results of pathological examination. In LY80 tumors 2 weeks after transplantation, blood flow in tumors treated with TNP-470 was higher than without TNP-470. This technique can be used to obtain information about the angiogenic status within tumor before and after antiangiogenic therapy. These angiogenic profiles may provide important clues to optimal antiangiogenic therapy, combinations of antiangiogenic treatment and cytotoxic therapy, and schedules for combination therapy.

Angiogenesis Inhibitors↗

PubMed2003

[Role of insulin-like growth factor I in the development of diabetic retinopathy].

Diabetic retinopathy is one of the main causes of blindness. This review will discuss the role of IGF-I in the pathogenesis of diabetic retinopathy. IGF-I is a growth factor with a very wide spectrum of biological activities. It especially controls cell growth and metabolic processes. Disorders of IGF-I activity, which are observed during diabetes, contribute to pathologic vascularization of the eye, particularly in the retina. Reasons for this is local hypoxia, which results from chronic hyperglycaemia; damage of blood retina barrier and disorder of the axis IGF-I--growth hormone. In the first stage of diabetic retinopathy the deficit of the systemic IGF-I can also be of importance. The role of IGF-I in diabetic retinopathy enables better understanding, and thus in the future better intensive antidiabetic therapy in aspect of ophthalmic complications.

Diabetic Retinopathy↗

PubMed1994

Oncogenes in the study of endothelial cell growth and differentiation.

During embryogenesis endothelial cells differentiate from mesodermal blood islands, proliferate and form new blood vessels throughout embryonic and early postnatal life by the processes of vasculogenesis and angiogenesis. Proliferation then ceases and is very low in the adult, although it resumes under certain physiological and pathological conditions, such as wound healing, tumor growth and hemangiomatous diseases. Expression of the polyoma middle T (PymT) oncogene in mouse endothelial cells leads to their rapid transformation and to the development of hemangiomas. These endothelial tumors allow the establishment of endothelioma (End) cell lines, which resemble normal endothelial cells yet exhibit a drastically altered proteolytic activity. The specific effects of PymT on the growth of endothelial cells appear in part to be mediated through the activation of cellular tyrosine kinases.

Animals↗

PubMed2006

Ultrasonographic portography with low mechanical index gray-scale imaging in hepatic VX2 tumor.

To evaluate the characteristics of portal blood supply of hepatic tumors by ultrasonographic portography (USP), an in vivo model was studied using SonoVue, a second-generation ultrasound contrast agent (UCA) and low mechanical index (MI), gray-scale harmonic imaging. SonoVue (0.05 mL) was administrated through catheter placed into the main trunk of portal vein at laparotomy, followed by a 0.5 mL saline flush, in 12 rabbits with hepatic VX2 tumor, implanted by VX2 tumor tissue cubes of approximately 1 mm3 from carrier rabbit. Results showed that low MI gray-scale imaging delineated clearly the dynamic enhancement of tumors and liver parenchyma. Among 22 tumors, seven tumors were diffusely increased, with the intensity of enhancement weaker than that of the surrounding liver parenchyma. The UCA was washed out earlier from tumors than from surrounding liver parenchyma. Three tumors showed the branches of portal vein. Five tumors showed peripheral contrast enhancement and a central coarse unenhanced hypoechoic area. Seven tumors displayed no actual enhancement. All lesions (100% [22 of 22]) were depicted clearly in the whole duration of enhancement, especially in the early and late phase, regardless of enhancement pattern, and portal blood flow was manifested in 15 of 22 (68%) tumors, by USP. The enhancement pattern of the tumors corresponded to the pathologic findings. The results indicated that ultrasonographic portography, combined with low MI levels and second-generation UCA, is a sensitive and safe method to study portal blood supply for liver cancer. It may contribute to improvement of the detectability and diagnostic ability and assist the choice of a therapeutic strategy for treatment of liver cancer. However, applicability of the method to human may be problematic because of high invasiveness and great difficulty in administering contrast medium.

Animals↗

PubMed1996

The role of angiogenesis in the spread of oral squamous cell carcinoma.

Microvessels were counted in 41 primary oral squamous cell carcinomas using JC70 antibody to PECAM (CD31). The counts were compared with clinical and pathological indicators of tumour behaviour including lymph node status, tumour stage, type of histological differentiation, size and velocity of tumour growth. Tumour microvessel counts correlated with lymph node metastasis (p < 0.001). This association was independent of tumour size, velocity and type of histological differentiation and when all the variables were analysed by multivariate analysis only vascular count showed a significant association with lymph node metastasis.

Carcinoma, Squamous Cell↗

PubMed2005

Discovery and validation of drug targets for tumour angiogenesis.

The formation of blood vessels is a key process in the progression of solid tumours, providing the means for tumour growth and metastasis. A number of drugs are currently being developed to exploit inhibition of angiogenesis in the therapy of cancer. An even greater number of genes that are regulated in models of in vitro angiogenesis have been identified. These genes present potential drug targets for the development of novel, more efficient, drugs that will enable the judicious design of drug cocktails that may be able to account for the many different cancer pathologies and their drug resistance properties. Dealing with the validation of hundreds of potential angiogenesis drug targets requires the utilisation of experimental technology platforms that enable concomitant and dynamic target selection filtering and validation. Such platforms should act as a funnel-like medium-to-low throughput processes that enable the sequential short-listing of hundreds of candidates culminating in the selection of only a small number of well-validated targets that are manageable by drug screening regimes.

Angiogenesis Inhibitors↗

PubMed2005

The realisation of targeted antitumour therapy.

Better understanding of the pathways regulating proliferation and metastasis of cancer cells has led to the development of novel molecular-targeted therapies. The number of molecular-targeted agents approved for use in the clinic is growing, with many more in clinical trials. Most of these compounds can be broadly classified into two main categories: monoclonal antibodies and small-molecule tyrosine kinase inhibitors. The pathological processes targeted include vascular endothelial growth factor-dependent tumour angiogenesis and epidermal growth factor receptor-dependent tumour cell proliferation and survival. Unlike conventional chemotherapy, molecular-targeted agents offer the potential advantages of a relatively high therapeutic window and use in combination with other anticancer strategies without overlapping toxicity. It is hoped that these drugs will become valuable therapeutic tools within the multimodal approach to treating cancer. Recent progress in targeted antitumour therapy is discussed, with a focus on antiangiogenesis.

Antibodies, Monoclonal↗

PubMed1993

Inverse relationship between hyaluronan and collagens in development and angiogenesis.

The extracellular matrix plays a vital role in regulating normal tissue development and function--largely via the specific arrangement of macromolecules such as collagens, proteoglycans, glycosaminoglycans and glycoproteins. Previous reports have concentrated on associations between combinations of collagens/proteoglycans, collagens/glycoproteins and proteoglycans/glycosaminoglycans whilst little information is available on associations between collagens and free glycosaminoglycans. In this review, we discuss possible associations between collagens and the glycosaminoglycan hyaluronan; macromolecules which are known to exhibit changes in amount and composition during development and under pathological conditions. We demonstrate two types of collagen/hyaluronan association in vivo: the first, during the formation of extracellular matrix structures where neither collagens nor hyaluronan are degraded, resulting in the regulation of collagen fibrillogenesis, and the second, involving an inverse correlation between collagen synthesis and hyaluronan degradation and vice versa. We suggest that associations between collagens and hyaluronan play an important role in the initiation and maintenance of angiogenesis and put forward a model of cartilage vascularisation which relies on these associations.

Animals↗

PubMed1996

Disorders of perfusion of the anterior segment of the eye.

BACKGROUND: We have investigated the vascular perfusion of a wide variety of conditions of the anterior segment using fluorescein angiography. METHODS: The conditions were classified and findings reported according to the system set out below. Patients underwent full ocular examination. Fluorescein angiography of the anterior segment was carried out when indicated to investigate iris atrophy and neovascularisation. Specular microscopy of the corneal endothelium was used to detect changes in this tissue. RESULTS: The hypoperfusion was variable in degree and accompanied by varying degrees of iris hypoplasia and atrophy with neovascularisation. The degree of neovascularisation depended upon its rapidity of development, the pre-existing state of vascular perfusion and the underlying pathological condition. CONCLUSIONS: Hypoperfusion with resultant ischaemia and neovascularisation is common in conditions of the anterior segment. An understanding of the changes is valuable in treating many conditions affecting the anterior segment. The changes observed may also occur elsewhere in the physical system and may be a significant part of the ageing process, either as scattered, disparate processes or as part of a general disease process.

Acute Disease↗

PubMed2006

Peptide-based molecules in angiogenesis.

Angiogenesis refers to the process of remodeling the vascular tissue characterized by the branching out of a new blood vessel from a pre-existing vessel. Angiogenesis is particularly active during embryogenesis, while during adult life it is quiescent and limited to particular physiologic phenomena. Recently, the study of molecular mechanisms of angiogenesis has stirred renewed interest due to the recognition of the role played by angiogenesis in several pathologies of significant medical impact, such as cancer and cardiovascular disease, and due to the pharmacologic interest rising from the possibility of modulating these phenomena. Antibodies, peptides and small molecules targeting active endothelial cells represent an innovative tool in therapeutic and diagnostic fields. In this study, we reviewed the literature of peptide and peptidomimetics in angiogenesis and their potential applications. Two specific protein systems, namely the vascular endothelial growth factor and its receptor and integrins, will be discussed in detail.

Animals↗

PubMed1998

Vascular endothelial growth factor expression and vascular density as prognostic markers of survival in patients with low-grade astrocytoma.

UNLABELLED: It has long been recognized that some patients with low-grade astrocytoma may survive for many years, whereas in others the disease follows a more malignant course resulting in a short survival time, usually due to malignant transformation into higher-grade tumors. OBJECT: The aim of this study was to investigate angiogenesis in the initial biopsy specimen of tumor tissue as a biological marker to identify patients with low-grade astrocytoma who are at high risk of malignant tumor transformation or death. METHODS: Tumor tissue was studied in 74 consecutively treated adult patients in whom a diagnosis of diffuse supratentorial hemispheric histologically proven fibrillary low-grade astrocytoma was made and who underwent surgery between January 1972 and January 1994. Studies were conducted using monoclonal antibodies to the antigens of the proliferation-associated Ki-67 (MIB-1), factor VIII, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF). The overall 5-year survival rate for the entire patient population was 65%, with a median survival time of 7.5 years. The total mean follow-up period was 6.1 years. All tumors showed a low proliferative potential at the time of the initial operation, as demonstrated by an MIB-1 labeling index of less than 1.5%. Patients with more than seven microvessels in tumor tissue (29 cases) had a shorter survival time (mean 3.8 years) than those with seven or fewer microvessels (mean survival 11.2 years). This difference in survival times was significant by univariate (p = 0.001) and stepwise multivariate analyses (p < 0.001). Tumors with a larger number of microvessels also had a greater chance of undergoing malignant transformation (p = 0.001). Similarly, significant staining for VEGF was correlated with shorter survival times when using univariate (p = 0.003) and multivariate (p = 0.008) analyses and with a greater chance of malignant transformation (p = 0.002). Patients with tumors staining positive for VEGF (39 individuals) had a median survival time of 5.3 years, and those with tumors negative for VEGF (35 patients) had a median survival time of 11.2 years. No association was observed between bFGF, EGF, and survival or malignant transformation. The stepwise multivariate analysis included histological and clinical variables simultaneously. CONCLUSIONS: The authors have shown that microvessel density and VEGF levels are independent prognostic markers of survival in fibrillary low-grade astrocytoma. This finding leads them to propose that fibrillary diffuse low-grade astrocytoma is not a single pathological entity but is composed of a spectrum of tumors with differing propensities to undergo malignant transformation that is at least partly based on their inherent angiogenic potential.

Adolescent↗

PubMed2004

Potential pathologic markers for prostate chemoprevention studies.

The field of exploring potential biomarkers for prostate cancer prevention continues to expand rapidly. In addition to a limited scope of histologic alterations, mainly PIN, a growing array of promising technologies (eg, computer-assisted analysis), and molecules involved in cell-cycle regulations, angiogenesis, and structural and numerical chromosomal alterations are potential candidates for surrogate endpoint biomarkers for prevention trials. Before any these potential candidates are adopted, however, the technical, interpretational, and validation requirements must be satisfied. More important, it is crucial to demonstrate that modulation of the frequency of the biomarker decreases the rate of cancer development.

Adenocarcinoma↗

PubMed2001

Angiogenesis-dependent diseases and angiogenesis therapy.

The discovery of the molecular mechanisms of physiological vasculogenesis and pathological angiogenesis helped to recognize two classes of diseases: one where the therapeutic angiogenesis can repair the tissue damages (arteriosclerosis, myocardial infarction, limb ischemia) and the other one where inhibition of pathological angiogenesis can cure the disease or delay its progression (retinopathies, benign and malignant angiogenic tumors, progression of malignant tumors). Although there are an exponentially growing number of new synthetic molecules characterized mainly by antiangiogenic properties, the discovery of a large battery of natural pro- and anti-angiogenic factors suggests that this may provide a more physiological approach to treat both class of angiogenesis-dependent diseases in the near future.

Angiogenesis Inhibitors↗

PubMed2006

The ever-elusive endothelial progenitor cell: identities, functions and clinical implications.

The concept of an Endothelial Progenitor Cell (EPC) that participates in adult angiogenesis is less than a decade old, yet it has received a great deal of attention due to its potential for cell-based clinical therapies in many pathologies. However, controversy remains as to the identity of this bone marrow-derived cell type and its ability to give rise to new endothelium in the adult. Reports on the contribution of EPCs to new vessels in ischemic tissue or tumors vary widely, ranging from 80-90% to negligible. As researchers hone their ability to identify, isolate, and expand these cells by their markers and functionality, mounting evidence suggests that they might constitute multiple, but related cell types. At least two general phenotypes have emerged from studies of bone marrow-derived cells contributing to angiogenesis: one that incorporates into the endothelial wall directly contributing to vascular expansion and another that is able to home to neovessels, but it locates behind the endothelial wall. Nonetheless, experimental evidence indicates that this second cell type supports the viability of newly formed vessels and thus it is equally relevant to neovascular growth. As our understanding of neovascularization in pathologic states expands, a more clear definition of the multiple cellular components required for the process will shed light into new models of therapeutic intervention. The identification of a cell type that could be isolated, expanded and infused into a patient would be very useful for promoting angiogenesis in ischemia, myocardial infarct and other pathologies.

Adult↗