Expression of von Willebrand's factor, CD34, CD31, and vascular endothelial growth factor in uterine leiomyomas

Generation of a novel model of bioengineered human oral mucosa with increased vascularization potential

Objective

The aim of this study was to generate novel models of bioartificial human oral mucosa with increased vascularization potential for future use as an advanced therapies medicinal product, by using different vascular and mesenchymal stem cell sources.

Background

Oral mucosa substitutes could contribute to the clinical treatment of complex diseases affecting the oral cavity. Although several models of artificial oral mucosa have been described, biointegration is a major issue that could be favored by the generation of novel substitutes with increased vascularization potential once grafted in vivo.

Methods

Three types of mesenchymal stem cells (MSCs) were obtained from adipose tissue, bone marrow, and dental pulp, and their in vitro potential was evaluated by inducing differentiation to the endothelial lineage using conditioning media. Then, 3D models of human artificial oral mucosa were generated using biocompatible fibrin‐agarose biomaterials combined with human oral mucosa fibroblasts and each type of MSC before and after induction to the endothelial lineage, using human umbilical vein endothelial cells (HUVEC) as controls. The vascularization potential of each oral mucosa substitute was assessed in vitro and in vivo in nude mice.

Results

In vitro induction of MSCs kept in culture was able to increase the expression of VEGF, CD31, and vWF endothelial markers, especially in bone marrow and dental pulp‐MSCs, and numerous proteins with a role in vasculogenesis become overexpressed. Then, in vivo grafting resulted in a significant increase in blood vessels formation at the interface area between the graft and the host tissues, with significantly positive expression of VEGF, CD31, vWF, and CD34 as compared to negative controls, especially when pre‐differentiated MSCs derived from bone marrow and dental pulp were used. In addition, a significantly higher number of cells committed to the endothelial lineage expressing the same endothelial markers were found within the bioartificial tissue.

Conclusion

Our results suggest that the use of pre‐differentiated MSCs could contribute to a rapid generation of a vascular network that may favor in vivo biointegration of bioengineered human oral mucosa substitutes.

Markers of Inflammation and Vascular Parameters in Selective Progesterone Receptor Modulator (Ulipristal Acetate)-Treated Uterine Fibroids

The exact mechanism of selective progesterone receptor modulator action in leiomyoma still challenges researchers. The aim of the study was to assess the effects of ulipristal acetate (UPA) on immunoexpression of inflammatory markers and vascularization in fibroids. UPA-treated patients were divided into three groups: (1) good response (≥25% reduction in volume of fibroid), (2) weak response (insignificant volume reduction), (3) and no response to treatment (no decrease or increase in fibroid volume). The percentage of TGFβ, IL6, IL10, CD117, and CD68-positive cells were significantly lower in the group with a good response to treatment vs. the control group. Moreover, the percentage of IL10 and CD68-positive cells in the group with a good response to treatment were also significantly lower compared to the no response group. Additionally, a significant decrease in the percentage of IL10-positive cells was found in the good response group vs. the weak response group. There were no statistical differences in the percentage of TNFα-positive cells and vessel parameters between all compared groups. The results of the study indicate that a good response to UPA treatment may be associated with a decrease of inflammatory markers, but it does not influence myoma vascularization.

Panax notoginseng saponins inhibits atherosclerotic plaque angiogenesis by down-regulating vascular endothelial growth factor and nicotinamide adenine dinucleotide phosphate oxidase subunit 4 expression

OBJECTIVE

To investigate the mechanism of Panax notoginseng saponins (PNS), an effective component extracted from Panax notoginseng, on atherosclerotic plaque angiogenesis in atherosclerosis-prone apolipoprotein E-knockout (ApoE-KO) mice fed with high-fat, high-cholesterol diet.

METHODS

Twenty ApoE-KO mice were divided into two groups, the model group and the PNS group. Ten normal C57BL/6J mice were used as a control group. PNS (60 mg/kg) was orally administered daily for 12 weeks in the PNS group. The ratio of plaque area to vessel area was examined by histological staining. The tissue sample of aortic root was used to detect the CD34 and vascular endothelial growth factor (VEGF) expression areas by immunohistochemistry. The expression of VEGF and nicotinamide adenine dinucleotide phosphate oxidase subunit 4 (NOX4) were measured by reverse transcription polymerase chain reaction and Western blotting respectively.

RESULTS

After treatment with PNS, the plaque areas were decreased (P<0.05). CD34 expressing areas and VEGF expression areas in plaques were significantly decreased (P<0.05). Meanwhile, VEGF and NOX4 mRNA expression were decreased after treatment with PNS. VEGF and NOX4 protein expression were also decreased by about 72% and 63%, respectively (P<0.01).

CONCLUSION

PNS, which decreases VEGF and NOX4 expression, could alleviate plaque angiogenesis and attenuate atherosclerosis.

Intraoperative bleeding during endoscopic sinus surgery and microvascular density of the nasal mucosa

PURPOSE

To evaluate the correlation between quality of the surgical field, intraoperative bleeding during endoscopic sinus surgery (ESS) and the density of microvasculature of the nasal mucosa.

MATERIAL/METHODS

Nasal mucosa of 30 patients, operated for chronic rhinosinusitis, was biopsied to assess expression of CD34 antigen on vascular endothelium. Quality of surgical field was evaluated with Fromm-Boezaart scale at mean arterial pressure (MAP) of 70-80 mmHg. If at this MAP surgical field quality was not satisfactory further reduction of hemodynamic parameters was performed until 'bloodless surgical field' (grade 2 or lower) was achieved. The rate of intraoperative bleeding was calculated from the ratio of total blood loss and the operative time. The extent of the disease was assessed according to computed tomography findings using Lund-Mackay staging system.

RESULTS

Significant positive correlation (Spearman correlation test; p<0.05) was found between CD34 antigen expression and quality of surgical field at MAP between 70 and 80 mmHg as well as the rate of intraoperative bleeding. More intense reduction of MAP was necessary to achieve 'bloodless surgical field' in patients with high CD34 expression than in those with moderate and low expression. Lund-Mackay score correlated with quality of surgical field but not with the rate of intraoperative bleeding.

CONCLUSION

During ESS, it is microvascular density of the nasal mucosa rather than the extent of the disease that contributes to the intensity of intraoperative bleeding, although both factors negatively influence the quality of surgical field.

Angiogenesis in pituitary adenomas: human studies and new mutant mouse models

The role of angiogenesis in pituitary tumor development has been questioned, as pituitary tumors have been usually found to be less vascularized than the normal pituitary tissue. Nevertheless, a significantly higher degree of vasculature has been shown in invasive or macropituitary prolactinomas when compared to noninvasive and microprolactinomas. Many growth factors and their receptors are involved in pituitary tumor development. For example, VEGF, FGF-2, FGFR1, and PTTG, which give a particular vascular phenotype, are modified in human and experimental pituitary adenomas of different histotypes. In particular, vascular endothelial growth factor, VEGF, the central mediator of angiogenesis in endocrine glands, was encountered in experimental and human pituitary tumors at different levels of expression and, in particular, was higher in dopamine agonist resistant prolactinomas. Furthermore, several anti-VEGF techniques lowered tumor burden in human and experimental pituitary adenomas. Therefore, even though the role of angiogenesis in pituitary adenomas is contentious, VEGF, making permeable pituitary endothelia, might contribute to adequate temporal vascular supply and mechanisms other than endothelial cell proliferation. The study of angiogenic factor expression in aggressive prolactinomas with resistance to dopamine agonists will yield important data in the search of therapeutical alternatives.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Enhanced nestin expression and small blood vessels in human pituitary adenomas

The role of angiogenesis in human pituitary tumor progression is questioned. Our aim was to characterize the morphologic changes that occur in the vasculature of pituitary adenomas, in correlation with the expression of nestin, a protein found in endothelial cells of newly formed vessels of developing organs. We also evaluated the relation of angiogenic markers and nestin with Ki-67 index. Immunohistochemical studies were performed on paraffin embedded samples of 47 pituitary adenomas and six normal pituitaries. We determined microvessel density (number of CD31+ or CD34+ vessels per square millimetre), vascular area (cumulative area occupied by vessels), average vessel size, and further classified vessels as small (< 100 μm2) or large (> 100 μm2). We correlated the above parameters with nestin expression and Ki-67 index. Lower vascular area compared to normal tissue was found in adenomas (p < 0.05). Interestingly, pituitary adenomas had significantly more small vessels than control pituitaries (p < 0.04 for CD31 and CD34). In tumors many capillaries were positive for nestin, while scarce staining was detected in controls, so that nestin positive area was significantly higher in tumors. Furthermore, nestin area correlated positively with the % of small vessels. Ki-67 correlated neither with vascular area nor with nestin expression. In human pituitary tumors there was a predominance of small capillaries in correlation with increased expression of the progenitor marker nestin. We suggest that angiogenesis is an active process in these tumors, in spite of their low total vascular area when compared to normal pituitaries.

Does three-dimensional power Doppler ultrasound predict histopathological findings of uterine fibroids? A preliminary study

OBJECTIVES

To compare three-dimensional (3D) power Doppler sonographic characteristics of fibroids with histopathological parameters.

METHODS

We evaluated sonographically 73 fibroids before myomectomy or hysterectomy. For each, the total fibroid volume, a shell of 3 mm and a 1-cm(3) spherical sample from the most vascularized area on subjective assessment were captured. 3D power Doppler vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were generated in the acquired volumes. The degree of cellularity, ischemic necrosis and fibrosclerosis, as well as CD31 and Ki-67 staining for vascular density and proliferation index, respectively, were estimated using the surgical sample. Pathological data were considered as dependent variables and ultrasound data as independent variables in multivariable logistic regression models including patients' characteristics.

RESULTS

A high histological 'cellular activity score', combining hypercellularity, a fibrosclerosis rate < 25% and positive Ki-67 staining, was statistically related in multivariate analyses to high 3D power Doppler VI in spherical samples (odds ratio (OR), 1.1 (95% CI, 1.0-1.3), P < 0.05) and VFI (OR, 1.3 (95% CI, 1.0-1.8), P < 0.05). Positive CD31 staining was statistically related to high 3D power Doppler VI in spherical samples (OR, 1.1 (95% CI, 1.0-1.3), P < 0.05). In contrast, ischemic necrosis was statistically related to low 3D power Doppler VI in the total volume (OR, 0.6 (95% CI, 0.4-1.0), P < 0.05) and VFI (OR, 0.4 (95% CI, 0.1-1.1), P < 0.05).

CONCLUSION

Vascular density, ischemic necrosis and histological cellular activity score are statistically significantly associated with some 3D power Doppler indices.

Decreased expression of pigment epithelium-derived factor and increased microvascular density in ovarian endometriotic lesions in women with endometriosis

OBJECTIVES

To determine whether women with endometriosis have altered expression of pigment epithelium-derived factor (PEDF) in ovarian endometriotic lesions as compared to women without endometriosis.

STUDY DESIGN

Ectopic and eutopic and normal endometrial tissues were sampled from 40 women with ovarian endometriosis and 20 control women, respectively. Endometrial PEDF expression and microvascular density (MVD) using an antibody to von Willebrand factor (vWF) and alpha-smooth muscle actin (α-SMA) were evaluated by using immunohistochemical staining.

RESULTS

We detected decreased PEDF expression and increased MVD using anti-vWF and -α-SMA in ovarian endometriotic lesions in women with endometriosis compared with the control group. In women with endometriosis, the MVD using anti-vWF and -α-SMA but not PEDF expression in ovarian endometriotic lesions correlated with the size of ovarian endometriotic cysts and the severity of the disease. Moreover, the MVD using anti-vWF was negatively correlated with PEDF expression in control endometrium but not in ovarian endometriotic lesions.

CONCLUSIONS

Our results suggest that decreased PEDF expression and increased MVD in ovarian endometriotic lesions might play an important role in the pathogenesis of ovarian endometriosis.

Angiogenesis in chronic rhinosinusitis with nasal polyps and in antrochoanal polyps

OBJECTIVES AND STUDY DESIGN

Angiogenesis may be related to the pathogenesis and prognosis of chronic rhinosinusitis with nasal polyposis. This cross-sectional study, in a tertiary university hospital, evaluates angiogenesis parameters in nasal polyps, antrochoanal polyps and middle turbinates.

SUBJECTS

Nasal polyps obtained from 24 consecutive patients, were compared to 10 normal middle turbinates and to 11 antrochoanal polyps.

METHODS

Analyzing for the expression of the angiogenic marker CD34 by immunohistochemistry. Blood vessels count, vascular surface density and microvessel density were measured by manual and computerized methods.

RESULTS

Angiogenesis was significantly higher in nasal polyps compared to control turbinates and to antrochoanal polyps (p = 0.0001 and p = 0.007, respectively). Antrochoanal polyps showed significantly more angiogenesis than normal middle turbinates (p = 0.001). Angiogenesis was not elevated in sub-groups of nasal polyposis patients considered to have worse prognosis.

CONCLUSIONS

Angiogenesis probably plays a role in the pathogenesis of both nasal polyposis and antrochoanal polyps. However, the significantly higher angiogenesis found in nasal polyps compared to antrochoanal polyps may support a different mechanism of growth. The lack of difference between angiogenesis and nasal polyposis patients sub-groups, may imply that angiogenesis is not associated with the prognosis of chronic rhinosinusitis with nasal polyposis.

Leukocyte density and composition in human cycling endometrium with uterine fibroids

In this study, we evaluated the leukocyte density and composition in the human cycling endometrium with uterine fibroids (UF). The endometrium with neighboring nodule (NN group, n = 62), autologous endometrium without NN (non-NN group, n = 62), and allogeneic endometrium without UF (non-UF group, n = 24) were immunostained for the leukocyte common and subset-specific antigens. The immunoreactive cells in the unit areas were enumerated under a light microscope. The stromal pan-leukocyte density in the proliferative phase was significantly higher in the endometrium in the NN group than in the non-NN group. The macrophage density was higher in the NN group than in the non-NN group throughout the menstrual cycle. The NK cell density in the mid-to-late secretory phase was lower in the NN group than in the non-NN group. The T cell density in the midsecretory phase was higher in the non-NN group than in the non-UF group. The neutrophil density in the proliferative phase was higher in the non-NN group than in the non-UF group. The leukocyte density and composition in the endometrium with UF are different from those without UF, suggesting their local effects on endometrial leukocyte population.

Microvessel density and area in pituitary microadenomas

Microvessel density (MVD) and area (MVA) were assessed in 53 clinically silent pituitary microadenomas and in surrounding normal pituitary tissue using CD34 immunostaining and digital image analysis system. Twenty-one microadenomas (40%) were avascular; in the others, both MVD and MVA were significantly lower than in the normal pituitary tissue. No significant differences in MVD and MVA were found between hormonally immunonegative and immunopositive tumors or between different hormonal subtypes of immunopositive microadenomas. In microadenomas and in normal pituitary tissue, MVD and MVA were not significantly influenced by age or sex. These results suggest that pituitary adenomas at early developmental stage are either avascular or significantly less vascular than normal pituitary tissue and that differences in vascularity of pituitary adenomas associated with the variables of sex, age, clinical presentation and immunohistochemical phenotype reported in the literature can evolve with tumor growth and possibly acquire statistical significance in large macroadenomas.

Assessment of the vascularity of uterine leiomyomas using double-echo dynamic perfusion-weighted MRI with the first-pass pharmacokinetic model: correlation with histopathology

OBJECTIVES

To retrospectively evaluate the feasibility of perfusion-weighted MRI (PWI) in uterine leiomyomas.

MATERIALS AND METHODS

: Eighteen uterine leiomyomas in 15 patients were evaluated. PWI was performed using a double-echo T2*-weighted spoiled gradient-recalled acquisition sequence, and the first-pass pharmacokinetic model was applied to calculate relative blood volume (rBV). Histopathologic analysis was performed to measure vascular area (VA).

RESULTS

PWI was successful in 13 of 15 patients. On quantitative analysis, mean (+/-SD) rBV calculated from PWI was 0.17 +/- 0.13 (range, 0.06-0.55), whereas mean VA was 3.3% +/- 1.6% (range, 1.7-8.5%). A significant correlation was identified between rBV and VA (r = 0.87, P < 0.001).

CONCLUSIONS

The rBV determined at PWI correlates with histologic vascular area in uterine leiomyomas.

Expression of terminally glycosylated calcitonin receptor-like receptor in uterine leiomyoma: endothelial phenotype and association with microvascular density

PURPOSE

The role for the hypoxia-inducible angiogenic factor adrenomedullin (AM) in tumor growth and progression has been suggested. Calcitonin receptor-like receptor (CL) is a G protein-coupled receptor (GPCR) that mediates effects of AM, but little information is available on its expression and functional state in human tumors. The present study attempted to determine CL potential for antiangiogenic therapy of uterine leiomyoma.

EXPERIMENTAL DESIGN AND RESULTS

GPCR CL is transported to the cell surface and recognized by AM only when terminally/mature glycosylated. The presence and localization of this form of the receptor in tumor and surrounding myometrial tissues obtained from leiomyoma-bearing uteri were examined using deglycosylation, immunoblotting, and immunofluorescence analysis. The mature CL glycoprotein was expressed in both tissues and localized exclusively in normal and tumor endothelium within leiomyoma-bearing uteri. The functionality of the receptor expressed in myometrial microvascular endothelial cells (MMVEC) was examined in vitro using receptor internalization and angiogenic assays. The mature CL glycoprotein expressed by primary MMVECs was functional because AM interacted with this GPCR and induced its internalization as well as angiogenic effects (proliferation and migration) in MMVECs in vitro. Finally, the levels of tissue-expressed mature CL glycoprotein as a functional form of this GPCR were analyzed by immunoblotting. The expression of this functional form of the receptor in vivo was significantly decreased (P = 0.01) in leiomyoma tissue, and this was concurrent with the decrease in microvascular density (measured by Chalkley counting) in tumor compared with surrounding myometrium (P = 0.031).

CONCLUSIONS

Our findings suggest that GPCR CL mediates angiogenic effects of AM in myometrium and that further evaluation of the properties of the CL expressed in both normal and tumor endothelium in vivo may be essential before targeting this endothelial GPCR for antiangiogenic therapies.

Future directions in myoma research

This article highlights our current knowledge of fibroids and addresses future directions for fibroid research and treatment over the next decade. The available data on cytogenetics are discussed, in addition to discoveries into signaling pathways and second messenger molecules in leiomyomas. Current medical management, surgical trends and the barriers to transition to minimally invasive procedures are summarized. Innovations in genetic diagnosis and interventional radiologic-aided therapies may revolutionize therapy for certain populations of patients who have fibroids. From tissue-specific medical management, to minimally invasive surgical techniques, to pharmacogenetics, the current directions of fibroid research are leading us to an exciting new frontier.

The normal human myometrium has a vascular spatial gradient absent in small fibroids

BACKGROUND

The human uterine vasculature is highly structured, exhibiting circumferential and radial branching. Previously published angiograms of the arterial network describe a system of regular coils. Uterine fibroids lack this structured vasculature. In this study, we make a comparison between the vasculature in normal myometrium and in fibroids using robust stereological methods thus far lacking in the literature.

METHODS

Stereological and morphometric analysis of the vascular system was carried out on 15 normal and 27 small fibroid (5-40 mm) uteri taken from women suffering menorrhagia. Projected images of published angiograms were also re-examined, measuring tortuosity.

RESULTS

A decreasing gradient of vascular smooth muscle from outer to inner myometrium was found in normal uteri, with no corresponding gradient in capillary tissue fraction. An association between vascular luminal size, amplitude and frequency of vessel bending was also established. Conversely, fibroids were found to lack structured or muscularized vasculature.

CONCLUSIONS

A quantitative gradient within the myometrial vascular system, which is absent in fibroids, has been demonstrated. These structural differences between diseased and healthy tissues are probably because of differing expression of angiogenic growth factors and may explain the distribution of particles seen after uterine artery embolization.

Vascular endothelial growth factor plays more than an angiogenic role in the female reproductive system

Although the most well-known function of vascular endothelial growth factor is its angiogenic activity, it plays more than a simple angiogenic role in the female reproductive system as it is involved in a number of key events in the course of the ovulatory cycle. The modulation of vascular endothelial growth factor expression varies in different reproductive tissues, probably related to its various functions at these different sites.

Novel mutations in FH and expansion of the spectrum of phenotypes expressed in families with hereditary leiomyomatosis and renal cell cancer

BACKGROUND

Hereditary leiomyomatosis and renal cell cancer (HLRCC; OMIM 605839) is the predisposition to develop smooth muscle tumours of the skin and uterus and/or renal cancer and is associated with mutations in the fumarate hydratase gene (FH). Here we characterise the clinical and genetic features of 21 new families and present the first report of two African-American families with HLRCC.

METHODS

Using direct sequencing analysis we identified FH germline mutations in 100% (21/21) of new families with HLRCC.

RESULTS

We identified 14 germline FH mutations (10 missense, one insertion, two nonsense, and one splice site) located along the entire length of the coding region. Nine of these were novel, with six missense (L89S, R117G, R190C, A342D, S376P, Q396P), one nonsense (S102X), one insertion (111insA), and one splice site (138+1G>C) mutation. Four unrelated families had the R58X mutation and five unrelated families the R190H mutation. Of families with HLRCC, 62% (13/21) had renal cancer and 76% (16/21) cutaneous leiomyomas. Of women FH mutation carriers from 16 families, 100% (22/22) had uterine fibroids. Our study shows that expression of cutaneous manifestations in HLRCC ranges from absent to mild to severe cutaneous leiomyomas. FH mutations were associated with a spectrum of renal tumours. No genotype-phenotype correlations were identified.

CONCLUSIONS

In combination with our previous report, we identify 31 different germline FH mutations in 56 families with HLRCC (20 missense, eight frameshifts, two nonsense, and one splice site). Our FH mutation detection rate is 93% (52/56) in families suspected of HLRCC.

Increased hyaluronan and CD44 expressions in intravenous leiomyomatosis

BACKGROUND

To determine the influence of hyaluronan and its receptor CD44 in the angiogenesis and invasiveness of intravenous leiomyomatosis (IVL).

METHODS

Paraffin-embedded sections from four IVL cases and 10 uterine leiomyoma cases were immunohistochemically stained for CD34, CD44, basic fibroblast growth factor (bFGF), vascular endothelial growth factor, and platelet-derived growth factor and assayed for microvessel densities. Hyaluronan was immunostained by biotinylated hyaluronan-binding peptide and the results were clinically correlated.

RESULTS

CD34 labeling showed significantly increased microvessel counts in IVL (156.6+/-3.7), when compared to uterine leiomyomas (61.3+/-27.3; P<0.001). Hyaluronan and its receptor CD44 were prominently expressed in IVL when compared to leiomyomas and associated with an elevation in bFGF expression.

CONCLUSIONS

IVL is a highly vascular neoplasm with elevated microvessel counts. The increase of hyaluronan and CD44 expression in IVL suggests that it is highly angiogenic and has an invasive potential. Elevation of hyaluronan may play a possible role in the pathogenesis of IVL.

Evidence of increased microvessel density and activation of the hypoxia pathway in tumours from the hereditary leiomyomatosis and renal cell cancer syndrome

The Mendelian tumour syndromes hereditary leiomyomatosis and renal cell cancer (HLRCC) and hereditary paragangliomatosis with phaeochromocytomas (HPGL) result from mutations in nuclear genes (FH and SDHB/C/D, respectively) that encode Krebs cycle enzymes. HPGL tumours are highly vascular and there is evidence that inactivation of SDH leads to activation of the hypoxia/angiogenesis pathway. In contrast, uterine leiomyomas are not generally regarded as particularly vascular lesions. In order to test the possibility that activation of the hypoxia/angiogenesis pathway contributes to tumourigenesis in HLRCC, increased vascularity and hypoxia pathway activation were searched for in HLRCC tumours. Microvessel density was markedly higher in uterine leiomyomas from HLRCC than in the surrounding myometrium; it was notable that sporadic uterine leiomyomas were actually less vascular than normal myometrium. In HLRCC tumours, there was increased expression of transcripts from the hypoxia-responsive genes vascular endothelial growth factor (VEGF) and BNIP3; sporadic uterine leiomyomas did not show these changes. All uterine leiomyomas showed decreased expression of thrombospondin 1. Although sporadic and HLRCC uterine leiomyomas appear to have identical morphology, their pathways of tumourigenesis may be fundamentally different. As is the case in HPGL, it is probable that failure of the Krebs cycle in HLRCC tumours causes inappropriate signalling that the cell is in a hypoxic state, leading to angiogenesis and perhaps directly to clonal expansion and tumour growth through some uncharacterized, cell-autonomous effect.

Prognostic value of von Willebrand factor, CD34, CD31, and vascular endothelial growth factor expression in women with uterine leiomyosarcomas

BACKGROUND AND OBJECTIVES

To compare uterine leiomyosarcomas (LMS) and leiomyomas (LM) with normal myometrium in terms of microvessel density (MVD), and to correlate this parameter with vascular endothelial growth factor (VEGF) expression and clinical/pathological parameters.

METHODS

An immunohistochemical technique, using antibodies against von Willebrand factor (FvW), CD34, CD31, and VEGF, was applied to formalin-fixed paraffin-embedded samples of 32 normal myometria, 32 uterine LM, and 12 LMS. MVD was calculated by a digital image analyzer.

RESULTS

Using anti-FvW, mean +/- SD MVD in myometrium, LM, and LMS was 107.0 +/- 53.6, 66.2 +/- 55.4, and 64.4 +/- 44.2, respectively (P = 0.001). MVD was lower in LMS (P = 0.021) and in LM (P = 0.0004) than in normal myometrium. Using anti-CD34, mean +/- SD MVD in myometrium, LM, and LMS was 187.6 +/- 91.2, 106.1 +/- 55.5, and 114.2 +/- 98.8, respectively (P = 0.001). MVD was lower in LMS (P = 0.012) and LM (P = 0.0004) than in normal myometrium. No such differences were found using anti-CD31 and anti-VEGF. No correlation was found between MVD and VEGF expression. In women with uterine LMS, low MVD (assessed with anti-FvW) correlated with recurrence (P = 0.04) and poor overall survival (P = 0.03).

CONCLUSIONS

Uterine smooth muscle tumors exhibit a lower MVD than normal myometrium, as assessed using anti-FvW or anti-CD34 antibodies. A reduced MVD, as assessed by FvW staining, has prognostic value in uterine LMS.