Prognostic value of bone marrow angiogenesis in multiple myeloma: use of light microscopy as well as computerized image analyzer in the assessment of microvessel density and total vascular area in multiple myeloma and its correlation with various clinical, histological, and laboratory parameters

Repopulation of decellularized organ scaffolds with human pluripotent stem cell-derived pancreatic progenitor cells

Diabetes is an emerging global epidemic that affects more that 285 million people worldwide. Engineering of endocrine pancreas tissue holds great promise for the future of diabetes therapy. Here we demonstrate the feasibility of re-engineering decellularized organ scaffolds using regenerative cell source. We differentiated human pluripotent stem cells (hPSC) toward pancreatic progenitor (PP) lineage and repopulated decellularized organ scaffolds with these hPSC-PP cells. We observed that hPSCs cultured and differentiated as aggregates are more suitable for organ repopulation than isolated single cell suspension. However, recellularization with hPSC-PP aggregates require a more extensive vascular support, which was found to be superior in decellularized liver over the decellularized pancreas scaffolds. Upon continued culture for nine days with chemical induction in the bioreactor, the seeded hPSC-PP aggregates demonstrated extensive and uniform cellular repopulation and viability throughout the thickness of the liver scaffolds. Furthermore, the decellularized liver scaffolds was supportive of the endocrine cell fate of the engrafted cells. Our novel strategy to engineer endocrine pancreas construct is expected to find potential applications in preclinical testing, drug discovery and diabetes therapy.

Pathogenesis and treatment of multiple myeloma bone disease

Multiple myeloma (Plasma cell myeloma), a malignancy of the plasma cells, exhibits tumor expansion preferentially in the bone marrow and the development of bone-destructive lesions. Multiple myeloma is still an incurable disease with changes in the bone marrow microenvironment in favor of the survival and proliferation of multiple myeloma cells and bone destruction. In this review, we described the recent findings on the regulators involved in the development of myeloma bone diseases, and succinctly summarize currently available therapeutic options and the development of novel bone modifying agents for myeloma treatment.

Myeloma-Bone Interaction: A Vicious Cycle via TAK1-PIM2 Signaling

Simple Summary

Myeloma cells interact with their ambient cells in the bone, such as bone marrow stromal cells, osteoclasts, and osteocytes, resulting in enhancement of osteoclastogenesis and inhibition of osteoblastogenesis while enhancing their growth and drug resistance. The activation of the TAK1–PIM2 signaling axis appears to be vital for this mutual interaction, posing it as an important therapeutic target to suppress tumor expansion and ameliorate bone destruction in multiple myeloma.

Abstract

Multiple myeloma (MM) has a propensity to develop preferentially in bone and form bone-destructive lesions. MM cells enhance osteoclastogenesis and bone resorption through activation of the RANKL–NF-κB signaling pathway while suppressing bone formation by inhibiting osteoblastogenesis from bone marrow stromal cells (BMSCs) by factors elaborated in the bone marrow and bone in MM, including the soluble Wnt inhibitors DKK-1 and sclerostin, activin A, and TGF-β, resulting in systemic bone destruction with loss of bone. Osteocytes have been drawn attention as multifunctional regulators in bone metabolism. MM cells induce apoptosis in osteocytes to trigger the production of factors, including RANKL, sclerostin, and DKK-1, to further exacerbate bone destruction. Bone lesions developed in MM, in turn, provide microenvironments suited for MM cell growth/survival, including niches to foster MM cells and their precursors. Thus, MM cells alter the microenvironments through bone destruction in the bone where they reside, which in turn potentiates tumor growth and survival, thereby generating a vicious loop between tumor progression and bone destruction. The serine/threonine kinases PIM2 and TAK1, an upstream mediator of PIM2, are overexpressed in bone marrow stromal cells and osteoclasts as well in MM cells in bone lesions. Upregulation of the TAK1–PIM2 pathway plays a critical role in tumor expansion and bone destruction, posing the TAK1–PIM2 pathway as a pivotal therapeutic target in MM.

Development of an Automated Image Analyzer for Microvessel Density Measurement in Bone Marrow Biopsies

Angiogenesis is important for the proliferation and survival of multiple myeloma (MM) cells. Bone marrow (BM) microvessel density (MVD) is a useful marker of angiogenesis and an increase in MVD can be used as a marker of poor prognosis in MM patients. We developed an automated image analyzer to assess MVD from images of BM biopsies stained with anti-CD34 antibodies using two color models. MVD was calculated by merging images from the red and hue channels after eliminating non-microvessels. The analyzer results were compared with those obtained by two experienced hematopathologists in a blinded manner using the 84 BM samples of MM patients. Manual assessment of the MVD by two hematopathologists yielded mean±SD values of 19.4±11.8 and 20.0±11.8. The analyzer generated a mean±SD of 19.5±11.2. The intraclass correlation coefficient (ICC) and Bland-Altman plot of the MVD results demonstrated very good agreement between the automated image analyzer and both hematopathologists (ICC=0.893 [0.840–0.929] and ICC=0.906 [0.859–0.938]). This automated analyzer can provide time- and labor-saving benefits with more objective results in hematology laboratories.

Evaluation of Angiogenesis in Multiple Myeloma by VEGF Immunoexpression and Microvessel Density

Background  Multiple myeloma (MM) is a plasma cell disorder characterized by monoclonal proliferation of plasma cells in bone marrow. Plasmablastic MM is a morphologic subset of MM, containing ≥2% plasmablasts of all plasma cells.

Methods  The study included 30 consecutively diagnosed patients of MM (6 plasmablastic, 24 nonplasmablastic) over a span of 2 years. Angiogenesis in MM was assessed by analysis of vascular endothelial growth factor (VEGF) immunoexpression by plasma cells and microvessel density (MVD) using anti-CD34 antibody. CD34 and VEGF immunohistochemical staining was performed in all the 30 cases. Angiogenesis was studied in relation to plasmablastic morphology and clinical profile to determine if any correlation exists between these.

Results  The mean VEGF expression of 80.83 ± 7.36 in plasmablastic myeloma cases was significantly higher compared with a mean VEGF of 53.54 ±17.09 in nonplasmablastic cases. Most of the cases (66.6%) of plasmablastic myeloma exhibited strong (3+) VEGF expression. The difference in mean VEGF expression between plasmablastic and nonplasmablastic cases was found to be statistically significant ( p = 0.001). The mean MVD in plasmablastic cases was 44.8 ± 3.69, while in the nonplasmablastic category, the mean MVD was 23.7 ± 5.14, difference being statistically significant ( p < 0.05). Also, a positive correlation was found between VEGF expression and MVD.

Conclusion  A moderate/strong VEGF intensity and higher MVD were found in cases of plasmablastic MM, suggesting that a more aggressive histological disease may be associated with increased production of VEGF. This finding might be helpful to identify a subset of patients with adverse prognosis and to provide antiangiogenic therapy to improve their survival. However, studies comprising larger number of patients are required to bring out a statistical significance to further substantiate these findings.

Promoted Angiogenesis and Osteogenesis by Dexamethasone-loaded Calcium Phosphate Nanoparticles/Collagen Composite Scaffolds with Microgroove Networks

Reconstruction of large bone defects remains a clinical challenge because current approaches involving surgery and bone grafting often do not yield satisfactory outcomes. For artificial bone substitutes, angiogenesis plays a pivotal role to achieve the final success of newly regenerated bone. In this study, dexamethasone-loaded biphasic calcium phosphate nanoparticles/collagen composite scaffolds with several types of concave microgrooves were prepared for simultaneous promotion of angiogenesis and osteogenesis. Microgrooves in the scaffolds were supposed to guide the assembly of human umbilical vascular endothelial cells (HUVECs) into well aligned tubular structures, thus promoting rapid angiogenesis. The scaffolds were used for co-culture of HUVECs and human bone marrow-derived mesenchymal stem cells. Subcutaneous implantation in mice showed that more blood vessels and newly formed bone were observed in the microgrooved composite scaffolds than in the control scaffold. Scaffold bearing parallel microgrooves with a concave width of 290 µm and a convex ridge width of 352 µm showed the highest promotion effect on angiogenesis and osteogenesis among the parallelly microgrooved composite scaffolds. The scaffolds bearing a grid network had further superior promotion effect to the scaffolds bearing parallel microgrooves. The results indicated that microgrooves in the composite scaffolds facilitated angiogenesis and stimulated new bone formation. The microgrooved composite scaffolds should be useful for repairing of large bone defects.

Extracellular vesicle cross-talk in the bone marrow microenvironment: implications in multiple myeloma

The bone marrow (BM) represents a complex microenvironment containing stromal cells, immune cells, osteoclasts, osteoblasts, and hematopoietic cells, which are crucial for the immune response, bone formation, and hematopoiesis. Apart from soluble factors and direct cell-cell contact, extracellular vesicles (EVs), including exosomes, were recently identified as a third mediator for cell communication. Solid evidence has already demonstrated the involvement of various BM-derived cells and soluble factors in the regulation of multiple biological processes whereas the EV-mediated message delivery system from the BM has just been explored in recent decades. These EVs not only perform physiological functions but can also play a role in cancer development, including in Multiple Myeloma (MM) which is a plasma cell malignancy predominantly localized in the BM. This review will therefore focus on the multiple functions of EVs derived from BM cells, the manipulation of the BM by cancer-derived EVs, and the role of BM EVs in MM progression.

Adverse prognostic impact of bone marrow microvessel density in multiple myeloma

Background

Angiogenesis is important for the proliferation and survival of multiple myeloma (MM) cells. Bone marrow (BM) microvessel density (MVD) is a useful marker of angiogenesis and is determined by immunohistochemical staining with anti-CD34 antibody. This study investigated the prognostic impact of MVD and demonstrated the relationship between MVD and previously mentioned prognostic factors in patients with MM.

Methods

The study included 107 patients with MM. MVD was assessed at initial diagnosis in a blinded manner by two hematopathologists who examined three CD34-positive hot spots per patient and counted the number of vessels in BM samples. Patients were divided into three groups according to MVD tertiles. Cumulative progression-free survival (PFS) and overall survival (OS) curves, calculated by using Kaplan-Meier method, were compared among the three groups. Prognostic impact of MVD was assessed by calculating Cox proportional hazard ratio (HR).

Results

Median MVDs in the three groups were 16.8, 33.9, and 54.7. MVDs were correlated with other prognostic factors, including β2-microglobulin concentration, plasma cell percentage in the BM, and cancer stage according to the International Staging System. Multivariate Cox regression analysis showed that high MVD was an independent predictor of PFS (HR=2.57; 95% confidence interval, 1.22-5.42; P=0.013). PFS was significantly lower in the high MVD group than in the low MVD group (P=0.025). However, no difference was observed in the OS (P=0.428).

Conclusions

Increased BM MVD is a marker of poor prognosis in patients newly diagnosed with MM. BM MVD should be assessed at the initial diagnosis of MM.

Plasma Levels of Monocyte Chemotactic Protein-1 Are Associated with Clinical Features and Angiogenesis in Patients with Multiple Myeloma

The aim of this pilot study was to determine the plasma levels of monocyte chemotactic protein-1 (MCP-1) and possible associations with angiogenesis and the main clinical features of untreated patients with multiple myeloma (MM). ELISA was used to determine plasma MCP-1 levels in 45 newly diagnosed MM patients and 24 healthy controls. The blood vessels were highlighted by immunohistochemical staining, and computer-assisted image analysis was used for more objective and accurate determination of two parameters of angiogenesis: microvessel density (MVD) and total vascular area (TVA). The plasma levels of MCP-1 were compared to these parameters and the presence of anemia, renal dysfunction, and bone lesions. A significant positive correlation was found between plasma MCP-1 concentrations and TVA (p = 0.02). The MCP-1 levels were significantly higher in MM patients with evident bone lesions (p = 0.01), renal dysfunction (p = 0.02), or anemia (p = 0.04). Therefore, our preliminary results found a positive association between plasma MCP-1 levels, angiogenesis (expressed as TVA), and clinical features in patients with MM. However, additional prospective studies with a respectable number of patients should be performed to authenticate these results and establish MCP-1 as a possible target of active treatment.

The hypoxia target adrenomedullin is aberrantly expressed in multiple myeloma and promotes angiogenesis

In multiple myeloma (MM), angiogenesis is strongly correlated to disease progression and unfavorable outcome, and may be promoted by bone marrow hypoxia. Employing gene-expression profiling, we here identified the pro-angiogenic factor adrenomedullin (AM) as the most highly upregulated gene in MM cells exposed to hypoxia. Malignant plasma cells from the majority of MM patients, belonging to distinct genetic subgroups, aberrantly express AM. Already under normoxic conditions, a subset of MM highly expressed and secreted AM, which could not be further enhanced by hypoxia or cobalt chloride-induced stabilization of hypoxia-inducible factor (HIF)1α. In line with this, expression of AM did not correlate with expression of a panel of established hypoxia-/HIF1α-target genes in MM patients. We demonstrate that MM-driven promotion of endothelial cell proliferation and tube formation is augmented by inducible expression of AM and strongly repressed by inhibition of endogenous and hypoxia-induced AM activity. Together, our results demonstrate that MM cells, both in a hypoxia-dependent and -independent fashion, aberrantly express and secrete AM, which can mediate MM-induced angiogenesis. Thus, AM secretion can be a major driving force for the angiogenic switch observed during MM evolution, which renders AM a putative target for MM therapy.

Synergistic effect of vascular endothelial growth factor and angiopoietin-2 on progression free survival in multiple myeloma

Bone marrow neoangiogenesis plays an important role in multiple myeloma (MM) and depends on the interplay of angiogenic cytokines. We investigated the levels of angiogenic cytokines such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiopoietin (Ang)-1, Ang-2 and hypoxia inducible factor-1 alpha (HiF-1α) in MM patients and their association with treatment outcome. Serum levels and mRNA expression of VEGF, Ang-2, Ang-1, bFGF and HiF-1α were evaluated in 71 MM patients using enzyme-linked immunosorbent assay and reverse transcriptase polymerase chain reaction. In multivariate Cox regression analysis, serum levels of VEGF≥756 pg/ml (HR 2.2, 95% CI 1.02-4.91; p=0.045) and relative mRNA expression levels of Ang-2≥0.93 (HR 21.0, 95% CI 6.27-70.45; p<0.001) were predictive of inferior progression free survival (PFS) and patients with concomitant increase in VEGF and Ang-2 had poor outcome compared to the rest of the patients (HR 32.6, 95% CI 7.20-148.36; p<0.001). These results suggest that VEGF and Ang-2 act in synergy and their expression levels at presentation are predictive of PFS in MM.

Assessment of bone marrow fibrosis and angiogenesis in monitoring patients with multiple myeloma

The aim of our study was to emphasize the importance of accurate and standardized techniques for detailed monitoring of the microenvironment in multiple myeloma (MM). Bone marrow fibrosis, angiogenesis, and plasma cell infiltrates in bone marrow biopsy (BMB) samples at the time of diagnosis and on completion of therapy were analyzed for 42 patients with newly diagnosed MM. Computerized image analysis was used for all slides stained with anti-CD138 and anti-CD34. The patients with fibrosis in pretreatment BMB samples had significantly higher microvessel density (MVD) and plasma cell infiltrates. In posttreatment BMB samples, nonresponders had a significantly higher frequency and grade of fibrosis and higher values of MVD, total vascular area, and plasma cell percentage. The overall survival of nonresponders and patients with increased marrow fibrosis in posttreatment BMB samples was significantly shorter. The obtained results confirm that complex morphologic examination of the bone marrow microenvironment during the monitoring of MM can provide better prognostic significance.

Rationally engineered nanoparticles target multiple myeloma cells, overcome cell-adhesion-mediated drug resistance, and show enhanced efficacy in vivo

In the continuing search for effective cancer treatments, we report the rational engineering of a multifunctional nanoparticle that combines traditional chemotherapy with cell targeting and anti-adhesion functionalities. Very late antigen-4 (VLA-4) mediated adhesion of multiple myeloma (MM) cells to bone marrow stroma confers MM cells with cell-adhesion-mediated drug resistance (CAM-DR). In our design, we used micellar nanoparticles as dynamic self-assembling scaffolds to present VLA-4-antagonist peptides and doxorubicin (Dox) conjugates, simultaneously, to selectively target MM cells and to overcome CAM-DR. Dox was conjugated to the nanoparticles through an acid-sensitive hydrazone bond. VLA-4-antagonist peptides were conjugated via a multifaceted synthetic procedure for generating precisely controlled number of targeting functionalities. The nanoparticles were efficiently internalized by MM cells and induced cytotoxicity. Mechanistic studies revealed that nanoparticles induced DNA double-strand breaks and apoptosis in MM cells. Importantly, multifunctional nanoparticles overcame CAM-DR, and were more efficacious than Dox when MM cells were cultured on fibronectin-coated plates. Finally, in a MM xenograft model, nanoparticles preferentially homed to MM tumors with ∼10 fold more drug accumulation and demonstrated dramatic tumor growth inhibition with a reduced overall systemic toxicity. Altogether, we demonstrate the disease driven engineering of a nanoparticle-based drug delivery system, enabling the model of an integrative approach in the treatment of MM.

Angiogenesis and multiple myeloma

The bone marrow microenvironment in multiple myeloma is characterized by an increased microvessel density. The production of pro-angiogenic molecules is increased and the production of angiogenic inhibitors is suppressed, leading to an "angiogenic switch". Here we present an overview of the role of angiogenesis in multiple myeloma, the pro-angiogenic factors produced by myeloma cells and the microenvironment, and the mechanisms involved in the myeloma-induced angiogenic switch. Current data suggest that the increased bone marrow angiogenesis in multiple myeloma is due to the aberrant expression of angiogenic factors by myeloma cells, the subsequent increase in pro-angiogenic activity of normal plasma cells as a result of myeloma cell angiogenic activity, and the increased number of plasma cells overall. Hypoxia also contributes to the angiogenic properties of the myeloma marrow microenvironment. The transcription factor hypoxia-inducible factor-1α is overexpressed by myeloma cells and affects their transcriptional and angiogenic profiles. In addition, potential roles of the tumor suppressor gene inhibitor of growth family member 4 and homeobox B7 have also been recently highlighted as repressors of angiogenesis and pro-angiogenic related genes, respectively. This complex pathogenetic model of myeloma-induced angiogenesis suggests that several pro-angiogenic molecules and related genes in myeloma cells and the microenvironment are potential therapeutic targets.

The microenvironment and molecular biology of the multiple myeloma tumor

Multiple myeloma (MM) is a deadly plasma cell cancer that resides in the bone marrow (BM). Numerous studies have demonstrated the involvement of the BM microenvironment supporting tumor growth, angiogenesis, bone disease and drug resistance. Reciprocal interactions between the different components of the BM microenvironment and the MM cells are necessary to regulate migration, differentiation, proliferation and survival of the malignant plasma cells. In this review we focus on the interactions and molecular mechanisms by which the BM microenvironment exert these effects. Better understanding of these interactions and the study of the epigenetic changes that tumor cells undergo are necessary in order to improve current treatments and for the discovery of new therapies that may eventually lead to a potential cure.

Does serum soluble vascular endothelial growth factor levels have different importance in pediatric acute leukemia and malignant lymphoma patients?

Vascular endothelial growth factor (VEGF) seems to play a central role in angiogenesis-lymphangiogenesis in hematological malignancies. There are limited data related to childhood hematologic malignancies. The aim of the study was to evaluate soluble VEGF (sVEGF) levels in children with acute leukemia and malignant lymphoma (ML) at diagnosis and in remission. The levels of serum sVEGF were measured by enzyme-linked immunosorbent assay (ELISA) in 20 children with acute leukemia, 33 children with different histopathological subtypes of ML, and 20 healthy controls. The levels of sVEGF at diagnosis (range 2 -1040 pg/mL; median 52 pg/mL) was significantly lower than in remission (range 136 -1960 pg/mL; median 630 pg/mL) in acute myeloid leukemia (AML) group (P = .018). The sVEGF levels at diagnosis (range: 2 -640 pg/mL; median 89 pg/mL) was significantly lower compared to remission values (range: 116 -1960 pg/mL; median 136 pg/mL) in patients with acute lymphoblastic leukemia (ALL) (P = .002). In ML group, including Burkitt's lymphoma (BL), T-cell non-Hodgkin's lymphoma (NHL), and Hodgkin's lymphoma (HL), sVEGF levels at diagnosis were higher than remission levels, but there was no statistically significant difference (P >.05). On the other hand, there were significant difference between levels in active disease and control group, ie, BL versus control, T-cell NHL versus control, and HL versus control (P = .008, P = .043, P = .007, respectively). The authors noticed that sVEGF levels showed distinct behavioral pattern in different childhood malignancies at diagnosis and in remission. In acute leukemia and ML patients, VEGF acts through different pathophysiological mechanisms, in both bone marrow (BM) angiogenesis and lymphoid tissue lymphangiogenesis.

[Whole body functional MR imaging: hemato-oncologic applications]

Hemato-oncologic imaging combines anatomical and functional imaging data for optimal staging and follow-up of patients. It is currently possible to achieve high spatial resolution and functional evaluation at whole body MR imaging. Functional imaging may be achieved with two techniques: dynamic imaging following intravenous contrast injection and diffusion-weighted imaging. The purpose of this article is to demonstrate how both functional imaging techniques can be combined with whole body MR imaging for the evaluation of multiple myeloma and lymphomas.

Multiple myeloma treatment response assessment with whole-body dynamic contrast-enhanced MR imaging

PURPOSE

To compare posttreatment bone marrow changes at whole-body dynamic contrast material-enhanced magnetic resonance (MR) imaging with clinical response in patients with multiple myeloma (MM) and to determine if this technique can be used to assess treatment response in patients with MM.

MATERIALS AND METHODS

This study was approved by an institutional review board; all patients gave informed written consent. Thirty patients (21 men, nine women; mean age, 58 years +/- 10 [standard deviation]) underwent whole-body dynamic contrast-enhanced MR imaging before treatment, after induction chemotherapy (n = 30), and after autologous stem cell transplantation (ASCT) (n = 20). Maximal percentages of bone marrow (BME(max)) and focal lesion (FLE(max)) enhancement were assessed at each MR imaging examination. Clinical responses were determined on the basis of international uniform response criteria. Posttreatment changes in BME(max)and FLE(max)were compared with clinical response to therapy by using the Mann-Whitney U test. Receiver operating characteristic (ROC) analysis of posttreatment BME(max)was used to identify poor responders.

RESULTS

Eleven of 30 patients were good responders to induction chemotherapy; 16 of 20 patients were good responders to ASCT. After induction chemotherapy, mean BME(max)differed between good and poor responders (94.3% vs 138.4%, respectively; P = .02). With the exclusion of results from six examinations with focal lesions in which a poor clinical response was classified but BME(max)had normalized, a posttreatment BME(max)of more than 96.8% had 100% sensitivity for the identification of poor responders (specificity, 76.9%; area under the ROC curve, 0.90; P = .0001). Mean FLE(max)after induction chemotherapy did not differ between good and poor responders. Mean timing (ie, the number of postcontrast dynamic acquisitions where FLE(max)was observed) was significantly delayed in good responders compared with poor responders (4.7 vs 2.9, P < .0001). Post-ASCT MR imaging results correctly depicted all four clinically good responders whose disease subsequently progressed.

CONCLUSION

With quantitative analysis of BME(max)and the timing of FLE(max), whole-body dynamic contrast-enhanced MR imaging can be used to assess treatment response in patients with MM.

Multiple myeloma

Advances in the imaging and treatment of multiple myeloma have occurred over the past decade. This article summarises the current status and highlights how an understanding of both is necessary for optimum management.

Computer-aided Image Processing of Angiogenic Histological

This article reviews the questions regarding the image evaluation of angiogeneic histological samples, particularly the ovarian epithelial cancer. Review is focused on the principles of image analysis in the field of histology and pathology. The definition, classification, pathogenesis and angiogenesis regulation in the ovaries are also briefly discussed. It is hoped that the complex image analysis together with the patient's clinical parameters will allow an acquiring of a clear pathogenic picture of the disease, extension of the differential diagnosis and become a useful tool for the evaluation of drug effects. The challenge of the assessment of angiogenesis activity is the heterogeneity of several objects: parameters derived from patient's anamnesis as well as of pathology samples. The other unresolved problems are the subjectivity of the region of interest selection and performance of the whole slide scanning.

KEYWORDS

Angiogenesis; Image processing; Microvessel density; Cancer; Pathology.

Tumor-associated macrophages infiltrate plasmacytomas and can serve as cell carriers for oncolytic measles virotherapy of disseminated myeloma

In multiple myeloma, some of the neoplastic plasma cells are diffusely dispersed among the normal bone marrow cells (bone marrow resident), whereas others are located in discrete, well-vascularized solid tumors (plasmacytomas) that may originate in bone or soft tissue. Interactions between bone marrow-resident myeloma cells and bone marrow stromal cells (BMSCs) are important determinants of myeloma pathogenesis. However, little is known of the factors sustaining myeloma growth and cell viability at the centers of expanding plasmacytomas, where there are no BMSCs. Histologic sections of 22 plasmacytomas from myeloma patients were examined after immunostaining. Abundant CD68+, CD163+, S100-negative macrophage infiltrates were identified in all tumors, accompanied by scattered collections of CD3+ T lymphocytes. The CD68+ tumor-associated macrophages (TAM) accounted for 2-12% of nucleated cells and were evenly distributed through the parenchyma. The TAM generally had dendritic morphology, and each dendrite was in close contact with multiple plasma cells. In some cases, the TAM were strikingly clustered around CD34+ blood vessels. To determine whether cells of the monocytic lineage might be exploitable as carriers for delivery of therapeutic agents to plasmacytomas, primary human CD14+ cells were infected with oncolytic measles virus and administered intravenously to mice bearing KAS6/1 human myeloma xenografts. The cell carriers localized to KAS6/1 tumors, where they transferred MV infection to myeloma cells and prolonged the survival of mice bearing disseminated human myeloma disease. Thus, TAM are a universal stromal component of the plasmacytomas of myeloma patients and may offer a promising new target for therapeutic exploitation. Am. J. Hematol. 2009. (c) 2009 Wiley-Liss, Inc.

Patients with plasma cell disorders examined at whole-body dynamic contrast-enhanced MR imaging: initial experience

This study was approved by the institutional review board, and informed consent was obtained from all subjects. The authors prospectively evaluated the feasibility of multistation whole-body dynamic contrast material-enhanced magnetic resonance (MR) imaging performed in patients with plasma cell disorders to assess disease extension and the time-signal intensity curves of diffuse and focal bone marrow infiltration. Three healthy adult male volunteers (age range, 29-31 years) and 21 patients (12 men, nine women; age range, 34-79 years) underwent whole-body dynamic unenhanced (volunteers) and contrast-enhanced MR imaging, which was performed by using an 18-channel 1.5-T MR system. A five-station (three sagittal and two coronal planes) fat-saturated three-dimensional gradient-echo sequence (3.3-3.6/1.3 [repetition time msec/echo time msec], 20 degrees flip angle, voxel size of 2 x 2.6 x [3-5] mm) was performed seven times. The temporal resolution of the five-station dynamic contrast-enhanced examination was 60 seconds with use of parallel imaging. Time-signal intensity curves for the bone marrow and the focal lesions were successfully obtained in all patients.

SUPPLEMENTAL MATERIAL

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Increased bone marrow microvascular density in haematological malignancies is associated with differential regulation of angiogenic factors

Antiangiogenic drugs are currently tested in haematological malignancies. As these drugs target different angiogenic regulators, and as cancers are inherently heterogeneous, a detailed characterization of angiogenesis in individual cancers is needed. Hence, we measured bone marrow microvessel density (MVD), plasma concentrations of eight angiogenesis-related parameters and the expression in blood mononuclear cells of 40 angiogenesis-related mRNAs in 93 patients with haematological neoplasias (acute myeloid leukaemia; chronic lymphatic leukaemia; multiple myeloma (MM); or non-Hodgkin's lymphoma (NHL)) before start and after completion of cancer therapy. Compared with healthy individuals, the patients had significantly increased bone marrow MVD, especially patients with advanced stage disease. A novel finding was that patients with NHL also had increased bone marrow MVD. The plasma levels of vascular endothelial growth factor (VEGF), interleukin (IL)-6 and IL-8 were significantly increased. VEGF levels were highest in those who did not achieve complete remission after cancer therapy. The mRNA expression of IL-8 was upregulated 15-fold. Our data show that patients with haematological malignancies have increased bone marrow MVD; hence, supporting the notion that bone marrow angiogenesis plays a role in the pathogenesis and progression of these cancers. VEGF, IL-6 and IL-8 seem to contribute to the malignant phenotype.

Bone marrow angiogenesis and angiogenic factors in multiple myeloma treated with novel agents

INTRODUCTION

An increased bone marrow (BM) angiogenesis is associated with poor outcome in multiple myeloma (MM).

OBJECTIVE

Angiogenesis study in MM treated with novel antimyeloma agents: thalidomide, lenalidomide, bortezomib, and with dexamethasone.

PATIENTS AND METHODS

Forty-four patients with MM (14 newly diagnosed, 30 refractory/relapsed) were treated with novel agents at our institution. A BM biopsy was obtained before the initiation of therapy in 19. Angiogenesis was assessed by microvessel density (MVD) estimation in BM biopsies stained with the monoclonal anti-CD34 antibody, and by serum levels of angiogenic factors (VEGF, bFGF, and HGF) and cytokines (IL-6 and TNF-alpha).

RESULTS

A positive correlation was found between BM plasma cell involvement and MVD estimation (p=0.01). However, MVD was not significantly correlated with either disease phase (p=0.065) or response to therapy (p=0.79). Neither baseline serum levels of angiogenic cytokines correlated to response to treatment. No significant correlation was found between BM MVD and serum levels of angiogenic cytokines. Serum levels of angiogenic cytokines before and after therapy showed a significant increase of bFGF (p=0.008).

CONCLUSION

There is no relationship between MVD estimation and baseline serum levels of angiogenic cytokines, neither between each of them and response to therapy.

Angiogenesis and antiangiogenic therapy in hematologic malignancies

Angiogenesis, the generation of new blood capillaries from preexisting blood vessels, is tightly regulated in the adult organism. Although many of the initial studies were performed on solid tumors, increasing evidence indicates that angiogenesis also plays an important role in hematologic malignancies. Overexpression of angiogenic factors in particular VEGF and bFGF in most hematologic malignancies may explain the increased angiogenesis found in these malignancies and correlate with poor prognosis as well as decreased overall survival. In this review, we focus on the current literature of angiogenesis and antiangiogenic therapy in hematologic malignancies, and finally describe advances and potential challenges in antiangiogenic treatment in hematologic malignancies.