Microvessel Pericyte Coverage Index Research Articles

Pericyte loss leads to microvessel remodeling and nasal polyp formation

Background Chronic rhinosinusitis (CRS) may be caused by increased vascular permeability and inflammatory cell leakage in the subepithelial tissue. Aims/objectives The aim of this study is to clarify the role of pericytes in tissue edema, microvessel dysfunction and vascular remodeling mechanisms in patients of CRS with nasal polyps (CRSwNP). Material and methods A total of 63 tissue samples were collected, including 42 CRSwNP samples (22 eosinophilic CRSwNP (eCRSwNP) and 20 non-eosinophilic CRSwNP (non-eCRSwNP) samples) and 21 samples of CRS without nasal polyps (CRSsNP). The samples were stained by immunofluorescence to measure microvessel density (MVD) and microvessel pericyte coverage index (MPI). Results We found that the albumin expression in the eCRSwNP group was significantly increased (p < .05). The MPI was significantly decreased (p <.05). There was a significant negative correlation between the MPI and the plasma albumin level (r=-0.82, p < .05). The MPI was negatively correlated with eosinophilic count (r=-0.77, p < .05). In the eCRSwNP group, the expressions of IL-4, Ang-1 and Ang-2 were increased compared with those in the control group. Conclusions and significance Pericyte loss may induce microvessel dysfunction, affect the development of interstitial edema and eosinophilic exosmosis in eCRSwNP, and contribute to the formation and maintenance of nasal polyps.

Changes in Tumor-Infiltrating Lymphocytes and Vascular Normalization in Breast Cancer Patients After Neoadjuvant Chemotherapy and Their Correlations With DFS.

Objective: Changes in the number of various tumor-infiltrating lymphocytes (TILs) and degrees of vascular normalization in breast cancer (BC) patients after neoadjuvant chemotherapy (NAC) were analyzed to screen key factors that can predict the prognosis.Methods: HE-stained sections were used to assess the degree of TILs infiltration; immunohistochemically stained sections were used to assess the infiltration of CD8+, CD4+, FOXP3+ Tregs and the expression of PD-L1; immunofluorescence-stained sections were used to assess the microvessel density (MVD) and microvessel pericyte coverage index (MPI). The expression of them before NAC were compared with those after NAC, and correlations between changes in these parameters and the pathological complete remission (pCR) and DFS of BC patients were analyzed.Results: After NAC, the percentage of patients with enhanced sTILs in the pCR group was significantly higher than that in the Non-pCR group (P < 0.05). Univariate and multivariate analyses showed that the number of FOXP3+ Tregs and MPI before NAC were correlated with pCR (P < 0.05). Survival analysis showed that the DFS of BC patients with reduced FOXP3+ Tregs was significantly better than that of patients with elevated FOXP3+ Tregs (P = 0.029). The sTILs count and MPI were significantly higher in primary tumors than lymph nodes (P < 0.05).Conclusion: After NAC, the reduced infiltration of FOXP3+ Tregs was correlated with an improvement in DFS in BC patients. Changes in the number of FOXP3+ Tregs and the MPI may be used as prognostic markers for BC patients.

Epigallocatechin-3-gallate-induced vascular normalization in A549-cell xenograft-bearing nude mice: therapeutic efficacy in combination with chemotherapy.

PurposeLarge-scale studies have revealed that appropriate antiangiogenic treatment enables the recovery of the normal structure and function of solid tumor vessels. Epigallocatechin-3-gallate (EGCG), a natural extract of green tea, has multiple effects on angiogenesis. However, normalization of blood vessels due to natural ingredients has not yet been reported. Therefore, we examined the microvasculature, microenvironment, and efficacy of EGCG combined with chemotherapy in a xenograft model.MethodsWe treated A549 cell (human lung adenocarcinoma cell line) xenograft-bearing nude mice with EGCG in vivo. CD31, αSMA, and collagen IV were labeled and detected using quantum-dot double-labeled immunofluorescence to measure microvessel density, microvessel pericyte-coverage index, and collagen IV expression. Vessel-perfusion function was determined by lectin injection, permeability by Evans blue extravasation, interstitial fluid pressure using the wick-in-needle technique, and hypoxia levels using a polarographic electrode and immunohistochemical pimonidazole labeling. Cisplatin concentration in tumor tissue was detected using graphite-furnace atomic absorption spectrophotometry. Xenograft mice were randomized into five groups: treated with saline, cisplatin, EGCG, EGCG + cisplatin on day 1, or EGCG + cisplatin during the vascular normalization window. Tumor-growth delay and tumor-suppression rate were measured to evaluate tumor growth.ResultsEGCG treatment in vivo caused temporary changes, including transient depression of microvessel density, microvessel pericyte-coverage index, and collagen IV expression, transient elevation of vessel perfusion and permeability, and decreased interstitial fluid pressure and hypoxia. During vascular normalization, pretreatment with EGCG increased cisplatin concentration in tumor tissue compared with treatment with cisplatin only. Tumor-growth delay after treatment in the five groups during the vascular normalization window was 6.3±1.51, 7.5±1.57, 8.3±1.79, 12.1±1.35, and 15.4±1.99 days, indicating synergistic EGCG–cisplatin effects, especially during the vascular normalization window (P<0.01).ConclusionEGCG-induced vascular normalization in human lung adenocarcinoma may be a novel modality for enhancing chemotherapy effects.

Investigation on the expression of microvessel pericyte coverage index and lymph vessel density in nasal polyps

Objective: To investigate the role of lymph vessel density (LVD) and microvessel pericyte coverage index (MPI) in the pathogenesis of nasal polyps. Methods: Using immunohistochemistry and immunofluorescence double staining method, the expressions of albumin, D2-40 and CD34-α-SMA in 11 specimens of normal nasal mucosa, 26 specimens of nasal polyp and 26 specimens of inferior turbinate tissue from patients with nasal polyps were investigated. The counts of microvessel density (MVD), lymph vessel density (LVD) and microvessel pericyte coverage index (MPI) were compared. SPSS 17.0 software was used to analyze the data. Results: The nasal polyp group(0.269±0.096) had more albumin than inferior turbinate tissue group(0.159±0.078) and normal nasal mucosa group(0.138±0.045), the differences were significant (q value was 4.873, 4.446, both P<0.05). The counts of MVD in nasal polyp group (30.52±4.42) were not significantly higher than those in inferior turbinate tissue group (30.33±6.03) and normal nasal mucosa group(28.21±6.84), the differences were not significant (q value was 0.130, 1.147, both P>0.05). The MPI in nasal polyp group (0.291±0.096) was significantly lower than those in inferior turbinate tissue group(0.432±0.101) and normal nasal mucosa group(0.416±0.071), the difference was significant (q value was 5.399, 3.680, both P<0.05). The counts of LVD in the nasal polyp group(0.245±0.073) were significantly lower than those in inferior turbinate tissue group (0.431±0.054) and normal nasal mucosa group(0.470±0.078), the difference was significant (q value was 10.004, 9.328, both P<0.05). MPI expression in the nasal polyp group was negetively correlated to albumin expression(r=-0.889, P<0.05). The LVD expression in the nasal polyp group was negetively correlated to albumin expression(r=-0.901, P<0.05). Conclusion: Different LVD and MIP in nasal polyp tissues and normal nasal mucosa tissues imply that microcirculatory dysfunction plays a crucial role in the pathogenesis of nasal polyps.

Blood oxygenation level-dependent magnetic resonance imaging during carbogen breathing: differentiation between prostate cancer and benign prostate hyperplasia and correlation with vessel maturity.

ObjectiveThe aim of this study was to investigate whether the blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) can evaluate tumor maturity and preoperatively differentiate prostate cancer (PCa) from benign prostate hyperplasia (BPH).Patients and methodsBOLD MRI based on transverse relaxation time*-weighted echo planar imaging was performed to assess PCa (19) and BPH (22) responses to carbogen (95% O2 and 5% CO2). The average signal values of PCa and BPH before and after carbogen breathing and the relative increased signal values were computed, respectively. The endothelial-cell marker, CD31, and the pericyte marker, α-smooth muscle actin (mature vessels), were detected with immunofluorescence, and were assessed by microvessel density (MVD) and microvessel pericyte density (MPD). The microvessel pericyte coverage index (MPI) was used to evaluate the degree of vascular maturity. The changed signal from BOLD MRI was correlated with MVD, MPD, and MPI.ResultsAfter inhaling carbogen, both PCa and BPH showed an increased signal, but a lower slope was found in PCa than that in BPH (P<0.05). PCa had a higher MPD and MVD but a lower MPI than BPH. The increased signal intensity was positively correlated with MPI in PCa and that in BPH (r=0.616, P=0.011; r=0.658, P=0.002); however, there was no correlation between the increased signal intensity and MPD or MVD in PCa than that in BPH (P>0.05).ConclusionOur results confirmed that the increased signal values induced by BOLD MRI well differentiated PCa from BPH and had a positive correlation with vessel maturity in both of them. BOLD MRI can be utilized as a surrogate marker for the noninvasive assessment of the degree of vessel maturity.

Tumor Angiogenesis in Breast Cancer: Pericytes and Maturation Does Not Correlate With Lymph Node Metastasis and Molecular Subtypes

BackgroundAngiogenesis, traditionally assessed by microvessel density (MVD), does not give an indication of the functional status of the tumor neovasculature. The structural and functional stability of the tumor vasculature and its potential clinical relevance in breast cancer was evaluated. Materials and MethodsIn invasive breast cancer, immunostaining of endothelial cells and pericytes was performed using anti-CD34 and anti–platelet-derived growth factor receptor-β antibody, respectively. Double immunostaining for the proliferating capillary index (PCI) and microvessel pericyte coverage index (MPI) was performed with CD34/Ki-67 and CD34/smooth muscle actin. ResultsThe mean MVD of 145 vessels/mm2 was significantly greater in grade 3 tumors (P = .018) and in necrotic tumors (P = .022). The PCI ranged from 0% to 17.14% (mean, 4.37%) and was associated with a high proliferative index in tumor tissue (P = .044). The MPI ranged from 13.09% to 88.18% (mean, 41.35%), indicating the stability of the tumor vasculature. However, it was not significantly associated with the tumor size, tumor grade, lymph node metastasis, proliferative index, or molecular subtypes. ConclusionMVD remains the angiogenesis-related parameter associated with tumor grade and necrosis. The PCI was the only functional parameter of angiogenesis associated with a poor prognostic indicator. The MPI did not show any correlation with the known prognostic and predictive factors.

Chemotherapy-Associated Angiogenesis in Neuroblastoma Tumors

The influences of cytotoxic drugs on endothelial cells remain incompletely understood. Herein, we examined the effects of chemotherapeutic agents in experimental angiogenesis models and analyzed vessel densities in clinical neuroblastoma tumor samples. Cisplatin (20 to 500 ng/mL), doxorubicin (4 to 100 ng/mL), and vincristine (0.5 to 4 ng/mL), drugs commonly involved in neuroblastoma therapy protocols, induced pro-angiogenic effects in different angiogenesis models. They enhanced endothelial cell tube formation, endothelial cell sprouting from spheroids, formation of tip cells in the sprouting assay, expression of αvβ3 integrin, and vitronectin binding. All three drugs increased global cellular kinase phosphorylation levels, including the angiogenesis-relevant molecules protein kinase Cβ and Akt. Pharmacological inhibition of protein kinase Cβ or Akt upstream of phosphatidylinositol 3-kinase reduced chemotherapy-induced endothelial cell tube formation. Moreover, the investigated chemotherapeutics dose dependently induced vessel formation in the chick chorioallantoic membrane assay. Tumor samples from seven high-risk patients with neuroblastoma were analyzed for vessel density by IHC. Results revealed that neuroblastoma samples taken after chemotherapy consistently showed an enhanced microvessel density compared with the corresponding samples taken before chemotherapy. In conclusion, our data show that chemotherapy can activate endothelial cells by inducing multiple pro-angiogenic signaling pathways and exert pro-angiogenic effects in vitro and in vivo. Moreover, we report a previously unrecognized clinical phenomenon that might, in part, be explained by our experimental observations: chemotherapy-associated enhanced vessel formation in tumors from patients with neuroblastoma.

Angiogenesis and host immune response contribute to the aggressive character of non-melanoma skin cancers in renal transplant recipients

The aim of this study was to determine the contribution of tumour angiogenesis to the aggressive growth of non-melanoma skin cancers (NMSCs) in renal transplant recipients (RTRs). The study cohort included RTRs (n = 38) with formalin-fixed paraffin-embedded tumour samples available from first post-transplant NMSC (NMSC1) surgically excised at Christchurch Hospital, New Zealand, from 1997 to 2007. Comparable samples excised from immunocompetent individuals (ICIs) (n = 36) were selected to accommodate confounding factors. Markers of tumour angiogenesis were evaluated by immunohistochemistry, and analysed for associations with clinicopathological variables. As compared with ICIs, RTRs had a higher proportion of tumours with high microvessel density (P = 0.008), high proliferating capillary index (P < 0.0001) and low microvessel pericyte coverage index (P < 0.0001), and RTRs had a shorter cumulative second NMSC (NMSC2)-free interval (P < 0.0001). ICIs had a higher proportion of tumours with a 'marked' number of vascular endothelial growth factor (VEGF)-A-positive leukocytes than RTRs (P = 0.04), and RTRs with a 'moderate/marked' number of VEGF-A-positive leukocytes had longer cumulative NMSC2-free intervals than those with a 'minimum' number (P = 0.02). This study demonstrates increased tumour angiogenesis in NMSC in RTRs, and suggests a role for VEGF-A-positive peritumoural leukocytes in suppressing NMSC development.

Increased vascular endothelial growth factor expression in patients with bladder pain syndrome/interstitial cystitis: its association with pain severity and glomerulations

To determine the angiogenic profiles in the bladder of patients with bladder pain syndrome (BPS)/interstitial cystitis (IC), and to evaluate the relationship between these profiles and associated clinical features including pelvic pain and glomerulations. Angiogenesis and angiogenic components are important in chronic inflammatory disease. High levels of vascular endothelial growth factor (VEGF) have been shown to induce immature angiogenesis, where microvessels have insufficient coverage of pericytes, resulting in haemorrhagic vessels. Biopsy specimens from 30 patients with BPS/IC and glomerulations, and 10 control patients, were examined immunohistochemically for VEGF expression, microvessel density (MVD) and immature microvessels. Pericyte coverage of microvessels in the specimens was used as an indicator of mature microvessels, and pericytes were identified by double-immunohistochemistry for CD34 and alpha-smooth muscle actin. The microvessel pericyte coverage index (MPI) was calculated as the ratio of mature vessels to total vessels. We also assessed the relationship between these angiogenic profiles and associated clinical features including pain and glomerulations. VEGF expression in the lamina propria was significantly higher in BPS/IC than in control samples (50% vs 10%, P < 0.05). Among patients with BPS/IC, VEGF expression was significantly higher in those with severe pain than in those with mild pain (78% vs 38%, P < 0.05). The MPI was significantly lower in BPS/IC than in control samples (23% vs 35%, P < 0.05), whereas MVD did not differ significantly between BPS/IC and control samples. There is increased VEGF and immature vascularization in patients with BPS/IC, and VEGF expression is associated with the degree of pain described by patients. Taken together, VEGF might contribute to pain and promote the formation of immature vessels in BPS/IC, and the increased immature vascularization might have a role in glomerulations in patients with BPS/IC.

Heterogeneity of angiogenesis and blood vessel maturation in cartilage tumors

Cartilage tumors have a special angiogenic phenotype, with blood vessels arranged predominantly in pericartilage fibrous septa and relatively low microvessel density (MVD), except in dedifferentiated chondrosarcomas. To further elucidate angiogenesis in cartilage tumors, we used double-labeling immunohistochemistry to determine microvessel pericyte coverage index (MPI) and proliferating capillary index (PCI), referring to blood vessel maturation and angiogenic activity in enchondromas, conventional chondrosarcomas, and dedifferentiated chondrosarcomas. Altogether, we found high MPIs (>70%) especially in dedifferentiated chondrosarcomas but without a correlation to the grade of malignancy. PCI was significantly higher in conventional chondrosarcomas grades II and III than in enchondromas, chondrosarcomas grade I, and dedifferentiated chondrosarcomas. Thus, PCI positively correlated with the previously reported differential expression of vascular endothelial growth factor (VEGF)-A in cartilage tumors. Altogether, cartilage tumors exhibit a heterogeneous but predominantly mature angiogenic phenotype with differential proliferative activity.

Chemo-angiogenic profile of bovine urinary bladder tumors distinguishes urothelial carcinomas from hemangiosarcomas

Angiogenesis and inflammation are two processes regulated by numerous common molecular mechanisms. Inflammation can stimulate angiogenesis, and angiogenesis can facilitate inflammation; both mechanisms have been shown to be involved in carcinogenesis. With this study we sought to gain an understanding of the molecular mechanisms involved in tumor angiogenesis and inflammation in urinary bladder tumors. Tumor specimens were collected at slaughter from Friesian cows chronically exposed to bracken fern. Bracken chronic toxicity is characterized by the presence of multiple mixed tumors in the bladder, being reported throughout the world under the designation of bovine enzootic hematuria. We conducted molecular analyses of angiogenic factors and chemokine production by real-time RT-PCR, and also assessed microvessel density (MVD), microvessel pericyte coverage index (MPI) to reveal mature vessels, the extent of tumor-infiltrating leukocytes (TILk) and tumor cell apoptosis and proliferation in both epithelial and endothelial-derived bovine urinary bladder tumors. We defined a profile of chemokines/chemokine receptors (Mip1β, CCR1) and angiogenesis-related factors (VEGF, VEGFR2) that allow distinguishing between urothelial carcinomas (epithelial origin) and hemangiosarcomas (endothelial origin). Taken together, our data reveals previously unrecognized paracrine and autocrine chemo-angiogenic loops in the context of bovine urinary bladder tumorigenesis.

Pericytes are correlated with the permeability of rat corneal neovascular vessels induced by alkali burn

Corneal neovascular leakage can lead to edema and secondary scarring. Previous studies have shown that pericytes play a key role in maturation of angiogenesis. The present studies investigate the relationship between vascular permeability and pericyte coverage of endothelial cells in rat corneal neovascular induced by alkali burns. Corneal neovascular vessels induced by alkali burns was performed in Sprague-Dawley rats. Corneas were excised on 1, 2, 3, 5, 7 and 10 days after cauterization. The vascular permeability rate was measured by the Evans blue method. The microvessel pericyte coverage index (MPI) was applied to quantify the pericyte coverage through double immunofluorescent staining of frozen sections of corneas with CD31 as the endothelial and alpha-smooth muscle actin (alpha-SMA) as the pericyte markers. The correlation between permeability rate and MPI was analyzed. Pericyte coverage was confirmed ultrastructually using transmission electron microscopy. The vascular permeability rate was (1.14 +/- 0.17), (0.24 +/- 0.08), (0.29 +/- 0.16), (0.14 +/- 0.10), (0.09 +/- 0.06) and (0.05 +/- 0.04) microg x ml(-1) x mm(-2) respectively on 1, 2, 3, 5, 7 and 10 days after cauterization. The MPI was 0, 16.07%, 11.95%, 43.84%, 73.97% and 86.21% respectively at the above mentioned time points. The correlation coefficient between MPI and the permeability rate was -0.943 (P = 0.005). Pericyte recruitment was significantly correlated with the permeability of corneal neovascularization induced by alkali burns in rats. Therapeutic strategies aiming at anti-leakage should be most effective if they promote pericytes proliferation in the course of corneal neovascularization.

Absence of Smooth Muscle Actin-Positive Pericyte Coverage of Tumor Vessels Correlates with Hematogenous Metastasis and Prognosis of Colorectal Cancer Patients

Objectives: Immature microvessels, which are not covered by pericytes, are irregular and leaky. We hypothesized that tumor cells can penetrate immature microvessels more easily than mature microvessels. In this study, we investigated the maturation of angiogenesis by the immunohistochemical staining of colorectal cancer specimens and determined the correlation between the microvessel count or the maturity of microvessels and clinicopathological variables. Methods: Ninety-two surgical specimens from our department were used. Double immunostaining of endothelial cells with anti-CD34 antibody and pericytes with anti-α-smooth muscle actin antibody was performed. The microvessel density (MVD) and microvessel pericyte coverage index (MPI) as an index of microvessel maturation were evaluated. Results: The MVD showed a significant positive correlation with tumor size, depth of invasion and Dukes’ stage. The MPI showed a significant positive correlation with the histological differentiation of the tumor tissues and distant metastasis at the time of operation. The high MVD group (≧26.0, n = 50) tended to have a poorer prognosis than the low MVD group (<26.0, n = 42) (p = 0.097). Next, the 50 patients in the high MVD group were classified into two subgroups of high MPI (≧78.1%, n = 25) and low MPI (<78.1%, n = 25). MPI showed a significant negative correlation with hematogenous metastasis, and the low MPI group demonstrated a significantly poorer survival than the high MPI group (p = 0.040). Conclusions: These findings demonstrate that immature neovascularization was observed in poorly differentiated tumors and was correlated with metastasis, resulting in a poorer prognosis. Taken together, not only microvessel density but also vascular maturation were crucial factors for colorectal cancer patients.