Tumour-type-specific capillary endothelial cell stainability in malignant B-cell lymphomas using antibodies against CD31, CD34 and Factor VIII

Cyclic-AMP signalling, MYC and hypoxia-inducible factor 1α intersect to regulate angiogenesis in B-cell lymphoma

Angiogenesis and MYC expression associate with poor outcome in diffuse large B-cell lymphoma (DLBCL). MYC promotes neo-vasculature development but whether its deregulation in DLBCL contributes to angiogenesis is unclear. Examination of this relationship may uncover novel pathogenic regulatory circuitry as well as anti-angiogenic strategies in DLBCL. Here, we show that MYC expression positively correlates with vascular endothelial growth factor (VEGF) expression and angiogenesis in primary DLBCL biopsies, independently of dual expressor status or cell-of-origin classification. We found that MYC promotes VEGFA expression, a correlation that was validated in large datasets of mature B-cell tumours. Using DLBCL cell lines and patient-derived xenograft models, we identified the second messenger cyclic-AMP (cAMP) as a potent suppressor of MYC expression, VEGFA secretion and angiogenesis in DLBCL in normoxia. In hypoxia, cAMP switched targets and suppressed hypoxia-inducible factor 1α, a master regulator of VEGFA/angiogenesis in low oxygen environments. Lastly, we used the phosphodiesterase 4b (Pde4b) knockout mouse to demonstrate that the cAMP/PDE4 axis exercises additional anti-angiogenesis by directly targeting the lymphoma microenvironment. In conclusion, MYC could play a direct role in DLBCL angiogenesis, and modulation of cAMP levels, which can be achieved with clinical grade PDE4 inhibitors, has cell and non-cell autonomous anti-angiogenic activity in DLBCL.

Nanotherapy silencing the interleukin-8 gene produces regression of prostate cancer by inhibition of angiogenesis

Interleukin-8 (IL-8) is a pro-angiogenic cytokine associated with aggressive prostate cancer (CaP). We detected high levels of IL-8 in sera from patients with CaP compared with healthy controls and patients with benign prostatic hypertrophy. This study examines the role of IL-8 in the pathogenesis of metastatic prostate cancer. We developed a biocompatible, cationic polylactide (CPLA) nanocarrier to complex with and efficiently deliver IL-8 small interfering RNA (siRNA) to CaP cells in vitro and in vivo. CPLA IL-8 siRNA nanocomplexes (nanoplexes) protect siRNA from rapid degradation, are non-toxic, have a prolonged lifetime in circulation, and their net positive charge facilitates penetration of cell membranes and subsequent intracellular trafficking. Administration of CPLA IL-8 siRNA nanoplexes to immunodeficient mice bearing human CaP tumours produced significant antitumour activities with no adverse effects. Systemic (intravenous) or local intra-tumour administration of IL-8 siRNA nanoplexes resulted in significant inhibition of CaP growth. Magnetic resonance imaging and ultrasonography of experimental animals demonstrated reduction of tumour perfusion in vivo following nanoplex treatment. Staining of tumour sections for CD31 confirmed significant damage to tumour neovasculature after nanoplex therapy. These studies demonstrate the efficacy of IL-8 siRNA nanotherapy for advanced, treatment-resistant human CaP.

The Role of Lymphocyte to Monocyte Ratio, Microvessel Density and HiGH CD44 Tumor Cell Expression in Non Hodgkin Lymphomas

Prognostic significance of immune microenvironment has been emphasized using the most advanced analysis, with consecutive attempts to reveal prognostic impact of this findings. The aim of this study was to compare and define prognostic significance of clinical parameters, microvessel density (MVD) in tumour tissue and expression of CD44s as adhesive molecule on tumour cells in diffuse large B cell lymphoma-DLBCL, primary central nervous system DLBCL-CNS DLBCL and follicular lymphoma-FL. A total of 202 histopathological samples (115 DLBCL/65 FL/22 CNS DLBCL) were evaluated. Overall response (complete/partial remission) was achieved in 81.3 % DLBCL patients, 81.8 % primary CNS DLBCL and 92.3 % FL. Absolute lymphocyte count-ALC/Absolute monocyte count-AMC >2.6 in DLBCL and ALC/AMC ≥ 4.7 in FL were associated with better event-free survival (EFS) and overall survival (OS) (p < 0.05). In DLBCL, MVD > 42 blood vessels/0.36 mm(2) correlated with primary resistant disease (p < 0.0001), poorer EFS and OS (p = 0.014). High CD44s expression in FL correlated with inferior EFS and OS (p < 0.01). In DLBCL, multivariate Cox regression analysis showed that ALC/AMC was independent parameter that affected OS (HR 3.27, 95 % CI 1.51-7.09, p = 0.003) along with the NCCN-IPI (HR 1.39, 95 % CI 1.08-1.79, p = 0.01). Furthermore, in FL, ALC/AMC mostly influenced OS (HR 5.21, 95 % CI 1.17-23.21, p = 0.03), followed with the FLIPI (HR 3.98, 95 % CI 1.06-14.95, p = 0.041). In DLBCL and FL, ALC/AMC is simple and robust tool that is, with current prognostic scores, able to define long-term survival and identify patients with inferior outcome. The introduction of immunochemotherapy might altered the prognostic significance of microenvionmental biomarkers (MVD and CD44s).

A phosphodiesterase 4B-dependent interplay between tumor cells and the microenvironment regulates angiogenesis in B-cell lymphoma

Angiogenesis associates with poor outcome in diffuse large B-cell lymphoma (DLBCL), but the contribution of the lymphoma cells to this process remains unclear. Addressing this knowledge gap may uncover unsuspecting proangiogenic signaling nodes and highlight alternative antiangiogenic therapies. Here we identify the second messenger cyclic-AMP (cAMP) and the enzyme that terminates its activity, phosphodiesterase 4B (PDE4B), as regulators of B-cell lymphoma angiogenesis. We first show that cAMP, in a PDE4B-dependent manner, suppresses PI3K/AKT signals to down-modulate VEGF secretion and vessel formation in vitro. Next, we create a novel mouse model that combines the lymphomagenic Myc transgene with germline deletion of Pde4b. We show that lymphomas developing in a Pde4b-null background display significantly lower microvessel density in association with lower VEGF levels and PI3K/AKT activity. We recapitulate these observations by treating lymphoma-bearing mice with the FDA-approved PDE4 inhibitor Roflumilast. Lastly, we show that primary human DLBCLs with high PDE4B expression display significantly higher microvessel density. Here, we defined an unsuspected signaling circuitry in which the cAMP generated in lymphoma cells downmodulates PI3K/AKT and VEGF secretion to negatively influence vessel development in the microenvironment. These data identify PDE4 as an actionable antiangiogenic target in DLBCL.

Effect of autologous adipose tissue-derived mesenchymal stem cells on neovascularization of artificial equine tendon lesions

AIMS

To investigate whether autologous adipose tissue-derived mesenchymal stem cells (AT-MSCs) treatment of tendon lesions increases neovascularization during tendon healing.

MATERIALS & METHODS

A standardized surgical model was used to create lesions in both front limb superficial digital flexor tendons (SDFTs) of nine horses. Either AT-MSCs or control substance was injected intralesionally 2 weeks post-surgery. Color Doppler ultrasonography of SDFTs was performed at regular intervals. Horses were euthanized 22 weeks post-treatment and SDFTs were harvested for histology.

RESULTS

The color Doppler ultrasonography signal was significantly more extensive at 2 weeks post-treatment and the number of vessels counted on histologic slides was significantly higher at 22 weeks post-treatment in AT-MSC-treated SDFTs.

CONCLUSION

Our findings indicate that AT-MSC treatment has a beneficial effect on neovascularization of healing tendons.

[Acquired haemophilia A: two cases]

BACKGROUND

Acquired haemophilia A (AH) is an uncommon bleeding disorder that presents as multiple, disseminated spontaneous subcutaneous bleeds. Diagnosis may be made on the basis of prolonged activated partial thromboplastin time (aPTT). The severity of the disease is associated with the low risk of haemoglobin levels and with potential links with other diseases.

OBSERVATIONS

Two men were hospitalized for extensive and spontaneous subcutaneous hematoma. In both cases, the International Normalized Ratio (INR) was normal, but aPTT was 3 times higher than normal. Autoantibodies against coagulation factor VIII confirmed the diagnosis of AH. The patients received immunomodulatory treatment. In one patient, diffuse large B-cell lymphoma was discovered one year after successful treatment of AH.

DISCUSSION

AH may be revealed by areas of bruising, subutaneous haematomas mimicking erythema nodosum, and muscle pain. APTT results alone can prompt the biologist to screen for factor VIII inhibitors. Aside from the risk of fatal bleeding, in half of all cases, the prognosis is determined by associated disorders such as blood dyscrasias, solid tumours, autoimmune diseases, use of certain medicines and pregnancy. After treatment for bleeding complications, therapy focuses on restoring the coagulation time. The aim of immunomodulatory therapy is to stem production of autoantibodies against coagulation factor VIII.

CONCLUSION

AH must be considered rapidly in order to reduce the risk of bleeding emergencies and to screen for potential related diseases.

Intra-articular venous malformations of the knee

BACKGROUND

Intra-articular venous malformations (IAVM) of the knee represent a rare group of low-flow vascular malformations, mainly reported in the literature as synovial hemangiomas, usually with an onset in early childhood. The main symptoms and signs are knee pain, swelling, and hemarthrosis. These lesions are slowly progressive and can lead to chronic synovitis and joint damage. Confusing nomenclature and classification of these lesions have often led to misdiagnosis and inappropriate treatment. We report our experience in the treatment of 14 consecutive patients affected by knee IAVM.

METHODS

We carried out a retrospective study based on the review of the medical records and diagnostic imaging of the patients admitted to our department from October 1999 to June 2009, and discharged with the final diagnosis of IAVM of the knee.

RESULTS

We observed 14 consecutive patients (8 boys, 6 girls); the median age at symptom onset was 5 years (range, 2.5 to 13 y). Magnetic resonance imaging was diagnostic in all cases. Surgical resection associated with a wide synoviectomy was the therapeutic procedure of choice in all cases. Within 6 months after surgery and physiotherapy, all the patients were symptom free with a full or at least acceptable knee range of motion. CD34 staining carried out in the last 7 cases of our series showed labeling of the endothelium of the thick-walled vessels, whereas the endothelium of the thin-walled vascular spaces was not stained. This finding of unstained vascular spaces suggests that a component of lymphatic vessels mixed with dysplastic blood vessels may be frequently present in these abnormalities.

CONCLUSIONS

Magnetic resonance imaging plays a pivotal role in identifying the lesion. Surgical excision is always indicated and should be performed as early as possible to avoid lesion progression and to reduce the risk of chondral degeneration. According to the microscopic features of our resected specimens, we suggest that these lesions of the knee should be more properly named as IAVM instead of hemangiomas.

LEVEL OF EVIDENCE

Level IV.

Assessment of bone marrow microvessel density in chronic lymphocytic leukemia

INTRODUCTION

Angiogenesis is a physiologic process of new blood vessels formation mediated by various cytokines called proangiogenic and antiangiogenic factors. Enhancement of angiogenesis in chronic lymphocytic leukemia (CLL) has been recognized more recently. Our study assesses CD34 and von Willebrand factor (vWf) expression and microvessel density (MVD) in the bone marrow of patients with CLL.

AIMS

(1) To assess bone marrow MVD in CLL using 2 different monoclonal antibodies, CD34 and vWf; and (2) To examine the possible association of marrow MVD and clinical course, pattern of marrow infiltration, Rai stage, CD38 positivity, and cytogenetic abnormalities detected by fluorescence in situ hybridization.

MATERIALS AND METHODS

Bone marrow specimens from 33 patients with CLL and 10 controls were studied. A single microvessel was defined as any vessel with a clear lumen. The screening of the slides was carried out by hotspot method. The slides were initially screened at low power to identify the areas with highest number of microvessel or vascularity hotspot. The count of microvessel in a sufficiently extended field (40x objective lens, 10x ocular lens) was then performed. The mean value of 10 most vascularized areas at 400x field was considered as MVD for a sample.

RESULTS

There was a significant difference between MVD counts according to the antibody used. MVD was higher using CD34 versus vWF (CD34: mean +/- SD, 35.91+/-15.7; 95% confidence interval of mean, 30.34-41.48 vessels/field versus vWF: 8.15+/-4.65; 95% confidence interval of mean, 4.11-12.44 vessels/field; P<0.0001]. Bone marrow MVD detected by CD34 was significantly higher in patients with CD38 expression more than 30% (P=0.006) and in patients with unfavorable cytogenetic abnormalities. However, no significant MVD differences were detected between CLL subgroups with regard to clinical course, pattern of marrow infiltration, and Rai stage. Bone marrow MVD in patients with CLL was significantly higher than that in controls (P<0.0001).

CONCLUSIONS

MVD assessment using anti-CD34 resulted in higher MVD counts than when using anti-vWF antibody. However, no MVD differences were detected between CLL subgroups subdivided according to the above-mentioned prognostic factors except CD38 expression and genetic abnormalities.

Prognostic impact of CD31-positive microvessel density in follicular lymphoma patients treated with immunochemotherapy

BACKGROUND

Tumour-infiltrating mast cells (MCs) can remodel tumour microenvironment and growth by suppressing immune responses and potentiating angiogenesis. Furthermore, accumulation of MCs in follicular lymphoma (FL) correlates with unfavourable prognosis after immunochemotherapy. Here we investigated whether tumour vascularity is associated with MC content and outcome in FL patients treated with immunochemotherapy.

PATIENTS AND METHODS

Microvessel density (MVD) and MC content were determined immunohistochemically from pretreatment samples of 95 FL patients using CD31, CD34 and mast cell tryptase antibodies. Gene expression data from a separate set of 24 FL patients were analysed for comparison. All patients were treated with the combination of rituximab (R) and cyclophoshamide-doxorubicin-vincristine-prednisone (CHOP) chemotherapy.

RESULTS

Increased CD31+ MVD correlated positively with the number of tumour infiltrating MCs and CD34+ vessels, and negatively with the outcome. Overall survival and progression-free survival were significantly better among patients with low CD31+ MVDs. In multivariate analyses, CD31+ MVD had prognostic value independently of Follicular Lymphoma Prognostic Index but not of MC content. Consistent with the immunohistochemical data, high CD31/PECAM1 mRNA levels were associated with adverse outcome. Conversely, a positive prognostic impact of VEGF mRNA expression on the outcome was found.

CONCLUSION

Vascularity is associated with MC content and outcome in R-CHOP-treated FL patients.

Immunohistochemistry in the evaluation of neovascularization in tumor xenografts

Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry is widely used in experimental studies for quantifying tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected by variations in the methodology used to measure vascularization including antibody selection, antigen retrieval (AR) pretreatment, and evaluation techniques. To examine this further, we investigated the microvessel density (MVD) and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg immunohistochemical staining. Different AR methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, anti-CD31 highlighted small vessels better than F VIII RAg. Furthermore, the MVD of CD31 was significantly greater than that of F VIII RAg decorated vessels (p<0.001). The choice of antibody and AR method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.

Is tumor vascularity in prostate core biopsies a predictor of PSA recurrence after radical prostatectomy?

The purposes of this study were to evaluate if tumour vascularity by Chalkley counting (TVC) in prostate core biopsies can be a predictor of PSA recurrence after radical prostatectomy in prostate cancer and to estimate the concordance between the TVC in core biopsies and the subsequently examined prostatectomy specimen. All patients, with Gleason score < or =7 in core biopsy, clinical stage T1 or T2 who had a radical prostatectomy during 1990-1997 at Sahlgrenska University Hospital, were selected as a primary group. Patients with neoadjuvant hormonal therapy were excluded. The patients were divided into two groups, one with PSA recurrence and one group without PSA recurrence. 25 patients had PSA recurrence during the follow up period and 25 patients from non-recurrence group were randomly selected. TVC was assessed from the prostate tissue by immunostaining against CD34. TVC was statistically significant predictor of PSA relapse. The PSA-free survival rate was only 17% in patients within the highest TVC quartile compared to 67% in patients within the lowest TVC quartile.

Testicular lymphoma--a retrospective, population-based, clinical and immunohistochemical study

From a population-based registry, 35 patients with histologically verified testicular lymphomas were identified: diffuse large B-cell lymphomas (DLBCL) in 33 and peripheral T-cell lymphomas in two cases. Twenty-two patients had localized disease (Pe stage I and II). Twenty-eight patients received systemic chemotherapy, 17 of whom also received intrathecal prophylaxis, and 12 out of these 17 also received radiotherapy to the contralateral testis. In the Pe stage I/II group, 7 out of 21 patients in complete remission (CR) relapsed. In 5 of them the CNS was involved (isolated CNS relapse in three). Remarkably late relapses occurred (up to 127 months). Intrathecal prophylaxis seemed to reduce the frequency of relapses involving the CNS, but the relatively short follow-up (median 45 months, range 34-88, for censored patients) prevents firm conclusions regarding efficacy. The outcome for the stage IV patients was poor, with only 1 out of 11 patients in continuous CR. Immunohistochemical analysis of the DLBCL tumours revealed that 31% had the germinal centre B-cell-like phenotype. CD44 was expressed in all the tumours of stage IV patients but in less than half of the Pe stage I/II patients. A high intratumoural microvessel density was correlated with a high degree of Ki-67 positive tumour cells and an inferior overall survival.

Choice of endothelial marker is crucial for assessment of bone marrow microvessel density in chronic lymphocytic leukemia

Angiogenesis is a potential prognostic factor in chronic lymphocytic leukemia (CLL). Elevated circulating levels of angiogenic factors in CLL have been repeatedly reported. Nevertheless, the issue of bone marrow neovascularization in CLL remains controversial, partly due to limited number of published studies, different methods of assessing microvessel density (MVD) and small patient cohorts. Moreover, there are very scarce data regarding the relationship of marrow angiogenesis to prognostic markers in CLL. Our objectives were: 1. To assess bone marrow MVD in CLL using two different monoclonal antibodies and a reproducible method of MVD quantification; 2. To examine the possible association of marrow MVD and clinical course, pattern of marrow infiltration, Rai stage, cytogenetic abnormalities detected by fluorescence in situ hybridization (FISH), and mutation status of immunoglobulin heavy chain variable region (IgVH). MVD was higher using CD34 vs vWF antibody (p<0.0001). However, no MVD differences were detected between CLL subgroups subdivided according to the above-mentioned prognostic factors. In conclusion, MVD assessment using anti-CD34 resulted in higher MVD counts than when using anti-vWF antibody. No association of MVD with any prognostic factors was observed, possibly due to the limited patient cohort. As the need for bone marrow trephine biopsies in CLL is significantly decreasing, a standardized method of neovascularization assessment is required to enable possible multicentre studies in order to conduct larger investigations and thereby shed more light on the real clinical significance of bone marrow angiogenesis in CLL.

Quantification of microvessels in canine lymph nodes

Quantification of microvessels in tumors is mostly based on counts of vessel profiles in tumor hot spots. Drawbacks of this method include low reproducibility and large interobserver variance, mainly as a result of individual differences in sampling of image fields for analysis. Our aim was to test an unbiased method for quantifying microvessels in healthy and tumorous lymph nodes of dogs. The endothelium of blood vessels was detected in paraffin sections by a combination of immunohistochemistry (von Willebrand factor) and lectin histochemistry (wheat germ agglutinin) in comparison with detection of basal laminae by laminin immunohistochemistry or silver impregnation. Systematic uniform random sampling of 50 image fields was performed during photo-documentation. An unbiased counting frame (area 113,600 microm(2)) was applied to each micrograph. The total area sampled from each node was 5.68 mm(2). Vessel profiles were counted according to stereological counting rules. Inter- and intraobserver variabilities were tested. The application of systematic uniform random sampling was compared with the counting of vessel profiles in hot spots. The unbiased estimate of the number of vessel profiles per unit area ranged from 100.5 +/- 44.0/mm(2) to 442.6 +/- 102.5/mm(2) in contrast to 264 +/- 72.2/mm(2) to 771.0 +/- 108.2/mm(2) in hot spots. The advantage of using systematic uniform random sampling is its reproducibility, with reasonable interobserver and low intraobserver variance. This method also allows for the possibility of using archival material, because staining quality is not limiting as it is for image analysis, and artifacts can easily be excluded. However, this method is comparatively time-consuming.

Application of cryobiopsy to morphological and immunohistochemical analyses of xenografted human lung cancer tissues and functional blood vessels

BACKGROUND

Assessment of tissue specimens obtained with common immersion-fixation followed by dehydration (IMDH) is affected by artifacts, which hinder precise evaluation of the histology and microenvironment of tumor tissues. The technical characteristics of cryobiopsy and in vivo cryotechnique (IVCT) where target organs are directly cryofixed in vivo are still unknown in practical examinations of tumor histopathology and microenvironment.

METHODS

Three lines of human lung cancer cells were subcutaneously injected to the dorsal flank of nude mice, and paraffin sections and cryosections of produced tumors were prepared with cryobiopsy, IVCT, the quick-freezing of the fresh resected tumor tissues, or IMDH. Histological comparison among different methods was conducted, and immunolocalization of immunoglobulin M (IgM), intravenously injected bovine serum albumin (BSA), and vascular endothelial growth factor (VEGF) were examined.

RESULTS

With both the cryobiopsy and IVCT, cellular morphology and open blood vessels with flowing erythrocytes could be observed without artificial shrinkage, and the volume of blood vessels was not affected by a vascular collapse, which was observed after tissue-resection. In addition, with cryobiopsy and IVCT, IgM was well preserved in functional vessels with blood flow, which could be observed with injected BSA, and the volume of IgM-immunopositive blood vessels was significantly associated with the expression of VEGF.

CONCLUSIONS

Cryobiopsy could be useful for histological examination of human tumors without morphological artifacts associated with IMDH. Furthermore, it allows direct examination of functional blood vessels and related signaling molecules, thereby providing a better evaluation of the human tumor microenvironment for clinical application.

Adenosine receptors in regulation of dendritic cell differentiation and function

Differentiation of functional dendritic cells (DCs) critically depends on the microenvironment. DCs differentiate in hypoxic tumor sites and inflamed or damaged tissue. Because local concentrations of adenosine reach high physiologically relevant levels in these conditions, we assessed the expression of adenosine receptors and the effect of their activation on differentiation of human monocytes and mouse peritoneal macrophages and hematopoietic progenitor cells (HPCs) into myeloid DCs. Stimulation of adenosine receptors skews DC differentiation toward a distinct cell population characterized by expression of both DC and monocyte/macrophage cell surface markers. Pharmacologic analysis and experiments with cells from A(2B) adenosine receptor knockout mice identified A(2B) receptor as the mediator of adenosine effects on DCs. Unlike normal myeloid DCs, adenosine-differentiated DCs have impaired allostimulatory activity and express high levels of angiogenic, pro-inflammatory, immune suppressor, and tolerogenic factors, including VEGF, IL-8, IL-6, IL-10, COX-2, TGF-beta, and IDO. They promoted tumor growth if injected into tumors implanted in mice. Using adenosine desaminase knockout animals, we showed that DCs with proangiogenic phenotype are highly abundant under conditions associated with elevated levels of extracellular adenosine in vivo. Adenosine signaling through A(2B) receptor is an important factor of aberrant DC differentiation and generation of tolerogenic, angiogenic, and proinflammatory cells.

Prognostic significance of VEGF, VEGF receptors, and microvessel density in diffuse large B cell lymphoma treated with anthracycline-based chemotherapy

Vascular endothelial growth factor-mediated signaling has at least two potential roles in diffuse large B cell lymphoma: potentiation of angiogenesis, and potentiation of lymphoma cell proliferation and/or survival induced by autocrine vascular endothelial growth factor receptor-mediated signaling. We have recently shown that diffuse large B cell lymphomas expressing high levels of vascular endothelial growth factor protein also express high levels of vascular endothelial growth factor receptor-1 and vascular endothelial growth factor receptor-2. We have now assessed a larger multi-institutional cohort of patients with de novo diffuse large B cell lymphoma treated with anthracycline-based therapy to address whether tumor vascularity, or expression of vascular endothelial growth factor protein and its receptors, contribute to patient outcomes. Our results show that increased tumor vascularity is associated with poor overall survival (P=0.047), and is independent of the international prognostic index. High expression of vascular endothelial growth factor receptor-1 by lymphoma cells by contrast is associated with improved overall survival (P=0.044). The combination of high vascular endothelial growth factor and vascular endothelial growth factor receptor-1 protein expression by lymphoma cells identifies a subgroup of patients with improved overall (P=0.003) and progression-free (P=0.026) survival; these findings are also independent of the international prognostic index. The prognostic significance of overexpression of this ligand-receptor pair suggests that autocrine signaling via vascular endothelial growth factor receptor-1 may represent a survival or proliferation pathway in diffuse large B cell lymphoma. Dependence on autocrine vascular endothelial growth factor receptor-1-mediated signaling may render a subset of diffuse large B-cell lymphomas susceptible to anthracycline-based therapy.

Diode laser-assisted carotid bypass surgery: an experimental study with morphological and immunohistochemical evaluations

OBJECTIVE

Conventional suturing methods of microvascular anastomosis are associated with various degrees of vascular wall damage that can lead to thrombosis and bypass occlusion. An experimental model of double end-to-side venous graft anastomosis on the common carotid artery was set up to compare conventional suturing methods with a low-power diode laser vascular welding technique.

METHODS

The experiments were performed on 40 rabbits that underwent implantation of a 15-mm segment of jugular vein on the common carotid artery. The proximal end-to-side suture was performed by eight interrupted stitches; the distal suture, which was done using a laser welding technique, was supported by four stay sutures. The animals were evaluated after 2 days (n = 15), 9 days (n = 15), and 30 days (n = 10). The vascular segments were excised and subjected to histological, immunohistochemical, and ultrastructural evaluation.

RESULTS

The average clamping time to perform both anastomoses was 35 minutes. At the end of the follow-up period, one case of complete occlusion was observed after 9 days and one case was observed after 30 days. Surgical observations and pathological evaluation indicated that adoption of the laser welding technique reduced operative time and bleeding. Histologically, a reduction of thrombosis, inflammation, myointimal hyperplasia, and dystrophic calcification was observed in laser-assisted anastomoses. A better preservation of the endothelium was also evident in laser-treated anastomoses. The observed differences were deemed statistically significant (P < 0.05).

CONCLUSION

Our study demonstrated the efficacy of diode laser welding in improving surgical techniques of high-flow bypass and in reducing the vascular wall damage observed with conventional methods.

Expression of cyclooxygenase-2 in Hodgkin's lymphoma: its role in cell proliferation and angiogenesis

Although many studies have revealed the association between cyclooxygenase-2 (COX-2) and carcinogenesis, the association between COX-2 and Hodgkin's lymphoma (HL) remains unknown. We examined the immunohistochemical expression of COX-2, p53, bcl-2, and Ki-67 in 33 patients with HL, and counted microvessels stained with CD34. Hodgkin and Reed - Sternberg (HRS) cells with COX-2 expression were scored as 0 = no staining; 1 = <25% of cells staining; 2 = 25-49%; 3 = 50-75%; and 4 = > or =75%. COX-2 expression was observed in 15 cases of classical HL. Nevertheless, neither accumulation of p53 nor bcl-2 expression was associated with COX-2 expression. The percentage of Ki-67 positive-HRS cells and microvessel density in COX-2 score groups 2-4 were significantly higher than those in score group 0, respectively. We show that COX-2 expression is associated with cell proliferation and angiogenesis in HL. These findings suggest that COX-2 may be a target for therapy in HL.

On metronomic chemotherapy: modulation of angiogenesis mediated by VEGE-A

Tumors are angiogenesis dependent. Preclinical studies have shown that well-tolerated continuous low dose, i.e. metronomic, chemotherapy can exert significant antiangiogenic effects per se and thereby a greater antitumor influence than conventional chemotherapy with high, spaced-out bolus doses. There are however, no means of quantitatively assessing the antiangiogenic effect of chemotherapy in tumors. We therefore used a surrogate tumor-free, non-surgical rat mesentery model and quantitatively studied the dose effect of metronomic treatment with cisplatin, cyclophosphamide, doxorubicin, fluorouracil and paclitaxel on VEGF-A-mediated angiogenesis, a characteristic of tumors. Cyclophosphamide and paclitaxel treatment exerted significant dose-dependent antiangiogenic effects, whereas doxorubicin treatment produced insignificant effects. By contrast, metronomic cisplatin and fluorouracil treatment occasionally significantly stimulated angiogenesis in a dose-dependent, non-linear manner. To our knowledge, this is the first report of metronomic chemotherapy stimulating angiogenesis in vivo. The data suggest that the angiogenic response to cisplatin, cyclophosphamide, fluorouracil and paclitaxel was significantly influenced by the presence of antioxidants in the vehicles or when co-treated with N-acetylcystein, a widely used free-radical scavenger. The data relating to the metronomic scheduling were compared with bolus treatment data for the identical agent formulations in the same experimental model. Cisplatin, cyclophosphamide and paclitaxel caused approximately the same overall, agent-specific angiogenesis-modulating effects following metronomic and bolus treatments. Moreover, apparently secondary delayed effects of chemotherapy affected capillary sprouting.

In vivo models of angiogenesis

The process of building new blood vessels (angiogenesis) and controlling the propagation of blood vessels (anti-angiogenesis) are fundamental to human health, as they play key roles in wound healing and tissue growth. More than 500 million people may stand to benefit from anti- or pro-angiogenic treatments in the coming decades [National Cancer Institute (USA), Cancer Bulletin, volume 3, no. 9, 2006]. The use of animal models to assay angiogenesis is crucial to the search for therapeutic agents that inhibit angiogenesis in the clinical setting. Examples of persons that would benefit from these therapies are cancer patients, as cancer growth and spread is angiogenesis-dependent, and patients with aberrant angiogenesis in the eye, which may lead to blindness or defective sight. Recently, anti-angiogenesis therapies have been introduced successfully in the clinic, representing a turning point in tumor therapy and the treatment of macular degeneration and heralding a new era for the treatment of several commonly occurring angiogenesis-related diseases. On the other hand, pro-angiogenic therapies that promote compensatory angiogenesis in hypoxic tissues, such as those subjected to ischemia in myocardial or cerebral hypoxia due to occluding lesions in the coronary or cerebral arteries, respectively, and in cases of poor wound healing, are also being developed. In this review, the current major and newly introduced preclinical angiogenesis assays are described and discussed in terms of their specific advantages and disadvantages from the biological, technical, economical and ethical perspectives. These assays include the corneal micropocket, chick chorioallantoic membrane, rodent mesentery, subcutaneous (s.c.) sponge/matrix/alginate microbead, s.c. Matrigel plug, s.c. disc, and s.c. directed in vivo angiogenesis assays, as well as, the zebrafish system and several additional assays. A note on quantitative techniques for assessing angiogenesis in patients is also included. The currently utilized preclinical assays are not equivalent in terms of efficacy or relevance to human disease. Some of these assays have significance for screening, while others are used primarily in studies of dosage-effects, molecular structure activities, and the combined effects of two or more agents on angiogenesis. When invited to write this review, I was asked to describe in some detail the rodent mesenteric-window angiogenesis assay, which has not received extensive coverage in previous reviews.

A new animal model to assess angiogenesis and endocrine function of parathyroid heterografts in vivo

BACKGROUND

It is still a matter of investigation how angiogenesis and restoration of gland perfusion determine graft function after free parathyroid autotransplantation. We provide a new animal model allowing simultaneous and repetitive in vivo assessment of angiogenesis and endocrine function of parathyroid transplants.

METHODS

Fresh human parathyroid tissue from patients with secondary hyperparathyroidism was grafted into dorsal skinfold chamber preparations of athymic nude mice (CD1-nu; n=8). Equivalent pieces of the same human donor specimens were heat-inactivated and served as control grafts (n=7).

RESULTS

In all animals receiving parathyroid transplants, intact human parathyroid hormone levels were detectable by species-specific enzyme-linked immunosorbent assay analysis of plasma samples on day 5 after transplantation and increased by 2.5-fold over the observation period (19 days) in contrast with controls. Plasma Ca levels revealed no differences between the groups. On day 5 after transplantation, intravital fluorescence microscopy revealed murine angiogenic microvessels sprouting along nonperfused human donor vessels, and 1 week later functional microvasculature was established in all parathyroid transplants. Histologic analysis revealed well-vascularized endocrine tissue. In contrast, control grafts were necrotic and partly resorbed; they exhibited no angiogenic activity or well-vascularized fat cells indicating fatty degeneration. In addition, species-specific Western blot analysis revealed vascular endothelial growth factor expression of parathyroid transplants rather than functional vessel density as the functional parameter of angiogenesis determining transplant function in vivo.

CONCLUSION

This model may serve to understand mechanisms associated with specific parathyroid transplant angiogenesis and its significance for transplant function to optimize clinical success of autotransplantation in therapy-resistant patients.

Quantification of angiogenesis in cervical cancer: a comparison among three endothelial cell markers

OBJECTIVES

The aim of this study was to evaluate the quantification of angiogenesis by assessing microvessel density in cervical cancer, comparing the performance of three monoclonal antibodies: anti-CD34 and BNH9, which are still little known markers in cervical neoplasia, and anti-CD31.

METHODS

Fifty-four consecutive patients diagnosed with stages I and II invasive cervical cancer undergoing radical hysterectomy and bilateral pelvic lymphadenectomy were evaluated. The monoclonal primary antibodies used were anti-CD34, anti-CD31 and BNH9 antibody. The areas of highest microvessel density were used for counting microvessels in 10 high-power fields. Microvessel density was the mean vessel number counted in 10 high-power fields.

RESULTS

The mean of microvessel density was 10.3, 9.7 and 5.8 for anti-CD34, BNH9 and anti-CD31, respectively. According to the Kruskal-Wallis nonparametric test, microvessel density estimated by anti-CD34 and BNH9 was significantly higher than the microvessel density estimated by anti-CD31. The difference between microvessel density measured by anti-CD34 and BNH9 was not statistically significant. There was diagnostic agreement in 44 out of 54 cases for anti-CD34 and BNH9 monoclonal antibodies, kappa coefficient being 0.63. The kappa coefficient was 0.41 between anti-CD34 and anti-CD31 and 0.26 between anti-CD31 and BNH9.

CONCLUSIONS

The anti-CD34 and BNH9 seem to have higher sensitivity than anti-CD31. The agreement to quantify microvessel density between anti-CD34 and BNH9 is higher than between them and anti-CD31. Additionally, considering that the BNH9 is much less unknown than anti-CD34 and that they showed very similar performance, the BNH9 clinical significance should be test in different neoplasms.