Bone Marrow Angiogenesis In Patients Research Articles

DCE-MRI to distinguish all monoclonal plasma cell disease stages and correlation with diffusion-weighted MRI/PET-based biomarkers in a hybrid simultaneous whole body-2-[18F]FDG-PET/MRI imaging approach

BackgroundDynamic contrast-enhanced-MRI (DCE-MRI) is able to study bone marrow angiogenesis in patients with multiple myeloma (MM) and asymptomatic precursor diseases but its role in the management of MM has not yet been established. The aims of this prospective study was to compare DCE-MRI-based parameters between all monoclonal plasma cell disease stages in order to find out discriminatory parameters and to seek correlations with other diffusion-weighted MRI and positron emission tomography (PET)-based biomarkers in a hybrid simultaneous whole-body-2-[18F]fluorodeoxyglucose (FDG)-PET/MRI (WB-2-[18F]FDG-PET/MRI) imaging approach.MethodsPatients with newly diagnosed Monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) or symptomatic MM according to international myeloma working group and underwent WB-2-[18F]FDG-PET/MRI imaging including bone marrow DCE sequences at the Nantes University Hospital were prospectively enrolled in this study before receiving treatment.ResultsOne hundred and sixty-seven patients (N = 167, mean age: 64 years ± 11 [Standard deviation], 66 males) were considered for the analysis. DCE-MRI-based Peak Enhancement Intensity (PEI), Time to PEI (TPEI) and their maximum intensity time ratio (MITR: PEI/TPEI) values were significantly different between the different monoclonal plasma cell disease stages, PEI values increasing and TPEI values decreasing progressively along the spectrum of plasma cell disorders, from MGUS stage to symptomatic multiple myeloma. PEI values were significantly higher in patients with diffuse bone marrow involvement (either in PET or in MRI images) than in those without diffuse bone marrow involvement, unlike TPEI values. PEI and TPEI values were not significantly different between patients with or without focal bone lesions.ConclusionDifferent DCE-MRI-based parameters (PEI, TPEI, MITR) could significantly differentiate all monoclonal plasma cell disease stages and complemented conventional MRI and PET-based biomarkers.

Ruxolitinib Therapy Effectively Modulates CD34+ Hematopoietic Progenitors and Bone Marrow Angiogenesis in Patients with Myelofibrosis

Background: Myelofibrosis (MF) associated with myeloproliferative neoplasms (MPN) is a multifactorial process resulting from profound modifications of the bone marrow (BM) and spleen stroma, as demonstrated by the presence of reticulin and collagen fibrosis, osteosclerosis and neo-angiogenesis. These stromal accumulations suggest a deregulation of BM stem cell niches, in which hematopoietic progenitor cells (HPCs) are engaged in a constant crosstalk with their stromal environment. Recently, there is strengthening evidence that the BM microenvironment which might contribute to the clinical outcomes in MF can be effectively modulated by JAK inhibitor therapy.Methods: A total of 68 patients (pts) with primary, post polycythemia vera or essential thrombocythemia MF, presenting at baseline (BL) with various degrees of BM fibrosis according to the WHO grading system, were selected from a phase 1/2 study (NCT00509899). All cases had both a BL and a sequential BM biopsy taken at 24 months (mo) following therapy with the JAK1/2 inhibitor ruxolitinib (RUX). Analysis included immunohistochemical and morphometric assessment of CD34+ HPCs (overall frequency, clustering index) by consensus after independent blinded review by 3 pathologists and computer assisted evaluation of BM angiogenesis. Quantification of microvascular density (MVD), luminal dilatation or microvessel area (MVA), and additional parameters, such as shape (form factor), tortuosity, and branching (maximal vessel length), were performed by whole slide digital imaging of the trephine biopsy and subsequent image processing using the ImageJ system. For 16 pts, additional analyses for vascular endothelial growth factor (VEGF) expression at BL and 24 mo were performed.Results: At BL, 79.5% of MF pts presented with a BM fibrosis grade of 2 or 3 according to the WHO definition. Following RUX therapy, 73.5% of cases showed an improvement or stabilization and in 6 pts (8.8%) a further regression to an earlier disease stage was observed. Increase in BM fibers was conspicuously accompanied by higher MVD and MVA at BL, which was also associated with elevated levels of angiogenic cytokines like VEGF. The structure of vessels at BL was significantly altered with an enhanced irregularity of shape and tortuosity. Post-RUX BM samples revealed a reduction in MVD -and in particular MVA- independent of BM fibrosis response. However, cases with improvement in fibrosis post-RUX showed a more profound change in microvessel architecture. Normalization of vessel structure was accompanied by a significant reduction of VEGF expression levels at 24 mo (p < 0.001). Overall frequency and clustering of CD34+ HPCs was reduced by RUX therapy at 24 mo. Improvement or stabilization of BM fibrosis post-RUX was in most cases associated with a corresponding reduction of CD34+ HPCs (88.9%) and a decreased clustering index (77.7%). In this regard, modulation of CD34+ HPCs was associated with a greater spleen size reduction at 24 mo (-10.9 vs -9.7 cm, p=0.061), whereas changes in hemoglobin values and platelet counts showed no correlation to this parameter. Similar effects were observed for MVD, MVA, and additional morphometric alterations of BM microvessel architecure.Conclusions: Our results support previous reports that therapy with the JAK inhibitor RUX effectively modulates the abnormal microenvironment that contributes to the maintenance of the neoplastic clone. In this regard, it is tempting to speculate that RUX therapy might modify vascular niches and therefore could impact the abnormal trafficking and homing of CD34+ HPCs and endothelial precursors that characterize MF. DisclosuresKvasnicka:Novartis: Consultancy, Honoraria, Research Funding; Incyte Corporation: Consultancy, Honoraria. Thiele:Novartis: Consultancy, Honoraria; Incyte Corporation: Consultancy, Honoraria. Verstovsek:Incyte Corporation: Research Funding.

Bone marrow angiogenesis in patients presenting with differential Chinese medicine syndrome: Correlation with the clinico-pathological features of aplastic anemia

To explore differences in bone marrow angiogenesis seen in aplastic anemia (AA) patients presenting with differential Chinese medicine (CM) syndrome, and to correlate these differences with clinical pathology. Thirty-five patients were enrolled, including 18 with "yang deficiency syndrome" and 17 with "yin deficiency syndrome." Bone marrow biopsies and serum were collected. Microvessel density (MVD) and positive expression of vascular endothelial-derived growth factor (VEGF) were detected by immunohistochemisty. Hypoxia inducible factor -1α (HIF-1α), and VEGF expression were assayed by enzyme-linked immunoabsorbent assay (ELISA), serum lactate dehydrogenase (LDH) was tested by enzyme method and liquid chip technology was used to detected the expression of interleukin (IL)-2, IL-4, IL-6, IL-10, interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Counts for leukocytes, absolute neutrophils and platelets in "yin deficiency syndrome" were lower than those found in "yang deficiency syndrome" (P<0.05). MVD and VEGF expression, and the positive rate of CD34 and VEGF in bone marrow were lower in AA, especially in "yin deficiency syndrome" (P<0.01 or P<0.05). "Yin deficiency syndrome" displayed decreased VEGF and LDH expression, and enhanced expression of HIF-1α as compared to "yang deficiency syndrome" (P<0.05). Levels of IL-4 and IL-6 were higher in AA (P<0.01), but IL-10 was decreased (P<0.05). High TNF-α expression was seen in "yang deficiency syndrome" and IFN-γ expression was decreased in "yin deficiency syndrome" as compared with normals (P <0.01 and P<0.05, respectively). AA patients have lower MVD than normals, especially in "yin deficiency syndrome." MVD might differentially correlate to disease severity, and could be dependent on bone marrow or serum VEGF expression and LDH. Additionally, IL-2, IL-10, IL-4 and IFN-γ were negatively associated while IL-6 and TNF-α were positively associated with MVD.

Hypoxia-inducible factor-2 is a novel regulator of aberrant CXCL12 expression in multiple myeloma plasma cells

Multiple myeloma is an incurable malignancy of bone marrow plasma cells. Progression of multiple myeloma is accompanied by an increase in bone marrow angiogenesis. Studies from our laboratory suggest a role for the CXCL12 chemokine in this process, with circulating levels of CXCL12 correlating with bone marrow angiogenesis in patients with multiple myeloma. While the mechanisms responsible for aberrant plasma cell expression of CXCL12 remain to be determined, studies in other systems suggest a role for hypoxia and hypoxia-inducible transcription factors. The expression of hypoxia-inducible factor protein was examined in patients' bone marrow biopsy specimens using immunohistochemistry. The hypoxic regulation of CXCL12 was examined in multiple myeloma plasma cell lines using polymerase chain reaction and western blotting. The role of hypoxia-inducible factors-1 and -2 in the regulation of CXCL12 expression was examined using over-expression and short hairpin RNA knockdown constructs, electrophoretic mobility shift assays and chromatin immunoprecipitation. The contribution of CXCL12 to hypoxia-induced angiogenesis was examined in vivo using a subcutaneous murine model of neovascularization. Strong hypoxia-inducible factor-2 protein expression was detected in CD138(+) multiple myeloma plasma cells in patients' biopsy specimens. Prolonged exposure to hypoxia strongly up-regulated CXCL12 expression in multiple myeloma plasma cells and hypoxia-inducible factor-2 was found to play a key role in this response. Promoter analyses revealed increased hypoxia-inducible factor-2 binding to the CXCL12 promoter under hypoxic conditions. Over-expression of hypoxia-inducible factor in multiple myeloma plasma cells strongly induced in vivo angiogenesis, and administration of a CXCL12 antagonist decreased hypoxia-inducible factor-induced angiogenesis. Hypoxia-inducible factor-2 is a newly identified regulator of CXCL12 expression in multiple myeloma plasma cells and a major contributor to multiple myeloma plasma cell-induced angiogenesis. Targeting the hypoxic niche, and more specifically hypoxia-inducible factor-2, may represent a viable strategy to inhibit angiogenesis in multiple myeloma and progression of this disease.

Prognostic Value of Bone Marrow Angiogenesis in Patients with Multiple Myeloma Undergoing High-Dose Therapy and Autologous Stem Cell Transplantation.

BACKGROUND. Angiogenesis is a constant hallmark of multiple myeloma (MM) progression. It has also been reported that bone marrow angiogenesis is a predictive factor of poor survival in newly diagnosed myeloma. The aim of the current study was to investigate the dynamics of bone marrow (BM) microvessel density (MVD) in patients undergoing high-dose therapy (HDT) and autologous stem cell transplantation (ASCT).PATIENTS AND METHODS. 36 patients with newly diagnosed MM (22 in stage II and 14 in stage III according to Salmon and Durie) were included in the study – 21 male and 15 female, median age – 51 ys (range 31–67). All patients underwent HDT that included 3–4 cycles of induction therapy (VAD), stem cell mobilization with cyclophosphamide 6 g/m2 and G-CSF 5 mcg/kg, EDAP and single or tandem ASCT with melphalan 200 mg/ m2. The BM biopsies for histological and immunohistochemical analysis were performed at the time of diagnosis, after induction, after stem cell mobilization before the 1st ASCT and after the end of therapy (5 times during the treatment). The Control group consisted of normal BM donors (7 male and 3 female, median age 29, (17–59)) who underwent BM biopsy during BM harvesting for alloBMT. Blood vessels were highlighted by immunostaining of endothelial cells with a monoclonal antibody to CD34 (Novocastra Lab Ltd). The MVD was calculated in 10 fields using an 40x objective and 16x ocular lens.RESULTS. At diagnosis in all MM pts, MVD was extremely high compared to normal donors (152±8 vs 74±4). A significant decrease of BM MVD was observed after each phase of therapy: after the induction therapy the MVD was 124±6; before the 1st ASCT – 109±5 and at the end of treatment – 97±3. There was a statistically significant increase of MVD after stem cell mobilization due to G-CSF (143±4). Although there was a marked decrease of BM MVD in MM pts with CR or VGPR, it nevertheless stayed significantly higher compared with control group (p<0,001). The analysis of probability of CR or VGPR duration after ASCT according to MVD at different phases of therapy showed that MVD at diagnosis and before the 1-st ASCT are important prognostic factors. Probability of duration of CR or VGPR was 63% in group with low MVD before the 1st ASCT compared with 15% in group with high MVD (p<0,02). MVD was revealed to be more powerful prognostic factor for progression free survival (PFS) then CR or VGPR achievement.CONCLUSION. BM angiogenesis is increased in patients with MM. BM MVD is decreased during and after treatment however even after the completion of HDT and ASCT, the MVD is higher then in the normal control group. There is a statistically significant increase of MVD after stem cell mobilization with cyclophosphamide and G-CSF. MVD at the time of diagnosis and before the 1-st ASCT are important prognostic factors for overall-survival and PFS after ASCT. MVD before the 1-st ASCT appears to be a more powerful prognostic factor for PFS then remission rate.

Assessment of Bone Marrow Angiogenesis in Patients with Acute Myeloid Leukemia by Using Contrast-enhanced MR Imaging with Clinically Approved Iron Oxides: Initial Experience

To prospectively assess bone marrow (BM) angiogenesis in patients with acute myeloid leukemia (AML) by using iron oxide-enhanced magnetic resonance (MR) imaging. The study was institutional ethics committee approved. Informed signed consent was obtained from each study participant. The requirement for informed consent for use of data from a reference database was waived. Eleven patients (seven women, four men; mean age, 53 years+/-4.40 [standard deviation]) with an initial diagnosis of AML were enrolled in the study and underwent T2*-weighted two-echo echo-planar MR imaging of the pelvis before and after intravenous injection of a clinically approved iron oxide blood-pool contrast agent. Six healthy control subjects (one woman, five men; mean age, 35 years+/-2.31) were examined with the same MR protocol. The iron oxide-induced change in R2* relaxation rate (DeltaR2*) was calculated, and the vascular volume fraction (VVF) of the BM was derived by dividing the DeltaR2* of the BM by the DeltaR2* of the muscle. Parametric DeltaR2* maps were calculated to visualize vessel distribution. Patients underwent BM biopsy for correlative determination of microvessel density (MVD) and vascular endothelial growth factor (VEGF). Differences in DeltaR2*, VVF, VEGF, and MVD were compared by using the Wilcoxon rank sum test. DeltaR2* maps showed prominent areas of highly vascularized BM in the patients with AML, whereas the control subjects had moderately vascularized BM with homogeneous vessel distribution. Quantitative analysis revealed VVF values to be significantly higher in patients with AML than in control subjects: The mean VVF in the pelvis was 9.18%+/-1.54 for patients versus 3.91%+/-0.61 for control subjects (P=.010). In accordance with MR results, MVD (P=.009) and VEGF expression (P=.017) were significantly elevated in the AML group compared with values in the control group. Iron oxide-enhanced MR imaging enables assessment of BM angiogenesis in patients with AML.

Iron Deficiency Status in Polycythemia Vera Correlates Well with Bone Marrow Angiogenesis in Patients Treated with Phlebotomy.

Background: Polycythemia vera (PV) is a chronic myeloproliferative disorder derived from multipotent hematopoetic precursors. The pathogenesis of PV is still poorly understood; furthermore, it is not clear, why the bone marrow (BM) of patients with PV has an increased microvessel density. Aims: For these reasons, we aimed to investigate, if BM angiogenesis and pathogenesis in PV are associated, and if the increased angiogenesis can elucidate pathophysiologic mechanisms of PV. Methods: BM biopsies were taken from patients with PV before and during treatment. A total of 38 samples from 35 patients were analyzed. In three patients, we investigated biopsies in 12 months intervals. Also, eight patients with iron deficiency were studied. BM angiogenesis in thin sections was determined by immunostaining of endothelial cells (CD34, vWF) and counting the microvessels. The microvessel counts were correlated to hematologic features such as treatment modalities and iron metabolism parameters (zinc protoporphyrin (ZPP), ferritin). Iron deficiency was classified to be mild for ZPP ≤ 100 micromol/mol hem (normal value < 40) and for ferritin 7 to 35 microgramm/l (normal value > 35), and to be severe for ZPP > 100 micromol/mol hem and for ferritin < 7 microgramm/l. Results: When compared to healthy controls, the number of BM microvessels in patients with iron deficient anemia was indistinguishable from healthy individuals. As expected, the BM microvessel numbers of patients with PV at diagnosis (n= 6) or with only mild iron deficiency treated with various therapy schedules (n=20) showed no significant difference (p=n. s.). In contrast, in patients with severe iron deficiency, we detected a highly significant difference between two different treatment modalities: phlebotomy alone was associated with a normal microvessel density (n=7; mean 3.6/mm2, range 2.7 to 5.7/mm2), whereas other treatment modalites or a combination with phlebotomy were associated with a high microvessel density (n=10; mean 10.4/mm2; range 4.5 to 15.7/mm2; p=0.0004). The microvessel counts of the patients from who two sequential biopsies were investigated are in line with these results: the microvessel numbers in a patient who received an oral iron treatment increased from 9.3 to 15/mm2; the microvessels of another patient who was treated with hydroxy urea and phlebotomy showed almost unchanged microvessel counts, whereas, in a third patient, who was treated exclusively by phlebotomy, a clear decrease of BM microvessel density from 15.7 to normal value of 4.5/mm2 was observed. Conclusions: We conclude that i) iron deficiency per se does not induce increased microvessel density in the BM, ii) a severe iron deficiency induced by phlebotomy alone can reduce the BM microvessel density in patients with PV to normal. Provided that the increased BM angiogenesis is associated with pathogenesis in PV, which means that the multipotent hematologic precursors account for the increased angiogenesis, efficient iron depletion by phlebotomy represents the highly potent treatment for PV.

Prognostic value of bone marrow angiogenesis in patients with multiple myeloma undergoing high-dose therapy.

Bone marrow (BM) angiogenesis is increased in multiple myeloma and is an important prognostic factor. However, prior studies were mainly done on patients receiving conventional chemotherapy and there is limited data on its prognostic value in patients undergoing high-dose therapy (HDT) as initial therapy. We studied BM angiogenesis in terms of microvessel density (MVD) in 88 newly diagnosed patients, who were uniformly treated, with 3-4 cycles of induction chemotherapy followed by HDT. We examined if MVD at diagnosis was predictive of response to induction therapy or to subsequent HDT. In addition, we also examined its prognostic value in these patients. The median MVD for primary refractory patients was 28 (range, 2-84) compared to 27 (range, 2-99) for responding patients (P=0.7). The median progression-free survival (PFS) was 21 months for those with high-grade angiogenesis compared to 42 months for those with low-grade angiogenesis, P=0.017. The median overall-survival (OS) from diagnosis was 40 months for those with high-grade angiogenesis and not yet reached, for those with low-grade angiogenesis, P=0.007. BM MVD at the time of initial diagnosis is an important prognostic factor for OS and PFS in patients undergoing autologous transplantation as frontline therapy for myeloma.

Proangiogenic properties of human myeloma cells: production of angiopoietin-1 and its potential relationship to myeloma-induced angiogenesis

AbstractPatients with multiple myeloma (MM) have increased bone marrow (BM) angiogenesis; however, the proangiogenic properties of myeloma cells and the mechanisms of MM-induced angiogenesis are not completely clarified. The angiopoietin system has been identified as critical in the regulation of vessel formation. In this study we have demonstrated that myeloma cells express several proangiogenic factors, and, in particular, we found that angiopoietin-1 (Ang-1), but not its antagonist Ang-2, was expressed by several human myeloma cell lines (HMCLs) at the mRNA and the protein levels. In a transwell coculture system, we observed that myeloma cells up-regulated the Ang-1 receptor Tie2 in human BM endothelial cells. Moreover, in an experimental model of angiogenesis, the conditioned medium of HMCLs significantly stimulated vessel formation compared with control or vascular endothelial growth factor (VEGF) treatment. The presence of anti-Tie2 blocking antibody completely blunted the proangiogenic effect of XG-6. Finally, our in vitro results were supported by the in vivo finding of Ang-1, but not Ang-2, mRNA and protein expression in purified MM cells obtained from approximately 47% of patients and by high BM angiogenesis in patients with MM positive for Ang-1, suggesting that the angiopoietin system could be involved, at least in part, in MM-induced angiogenesis.

Bone marrow angiogenesis in multiple myeloma: effect of therapy.

Recent studies have demonstrated that angiogenesis has a role in haematological malignancies, including multiple myeloma. Multiple myeloma is characterized by inevitable relapse after standard or high-dose chemotherapy. To study the effect of chemotherapy on bone marrow angiogenesis in patients with multiple myeloma, we used two methods to evaluate bone marrow angiogenesis in patients with newly diagnosed multiple myeloma, comparing these findings with those from bone marrow obtained after standard chemotherapy. Before therapy, an increased degree of bone marrow angiogenesis and a high bone marrow plasma cell labelling index (PCLI) were predictive of poorer survival. As estimated by microvessel density (MVD), the median survivals for patients with low-grade, intermediate-grade and high-grade angiogenesis were 77, 30 and 14 months respectively. After therapy, the MVD did not change significantly. However, when patients with at least a partial response were considered separately, they showed a decrease in MVD. Post-therapy PCLI was predictive of survival, but post-therapy MVD was not. There was good correlation between angiogenesis estimated by visual grading and that determined by MVD assessment. We conclude that the degree of bone marrow angiogenesis is a prognostic marker in patients with multiple myeloma and does not decrease significantly after therapy.

Prognostic value of enhanced bone marrow angiogenesis in early B-cell chronic lymphocytic leukemia

AbstractBecause tumor progression is angiogenesis-dependent, angiogenesis density was investigated by immunohistochemistry and computed image analysis in bone marrow (BM) biopsies of 45 newly diagnosed patients with Binet stage A B-cell chronic lymphocytic leukemia (BCLL) and correlated to upstaging and progression-free survival during a 40-month follow-up period. Their microvessel areas and counts were significantly higher than those of patients with anemia due to iron or vitamin B12deficiencies. A cutoff value of 0.90 mm2 × 10−2 or greater of the microvessel area identified patients with earlier upstaging and shorter progression-free survival. When the cutoff was applied to the Rai subclassification, both Rai 0 and Rai I-II patients who upstaged and shortened the progression-free survival were classified correctly. Information of this type was not given by the microvessel counts. The cutoff did not correlate with other predictors representative of tumor mass or disease progression. The microvessel area correlated with the expression of angiogenic vascular endothelial growth factor (VEGF) by tumor tissue, and serum levels of VEGF were found to be of prognostic value. A causal relationship between risk of progression and BM angiogenesis in BCLL is suggested. A risk stratification inside Rai is proposed. The prognostic usefulness of BM angiogenesis in patients with BCLL is envisaged.

Bone marrow angiogenesis in patients with active multiple myeloma

Factor VIII-related antigen (FVIII-RA)-positive microvessel areas were measured by both immunohistochemistry and computerized image analysis in patients with active multiple myeloma (MM), nonactive MM, and monoclonal gammopathies of undetermined significance (MGUS). A five-to sixfold larger area was found in patients with active MM compared to the other two groups. Aquaporin I (AQPI)-positive microvessel areas, measured with the same techniques on adjacent tissue sections, were also increased in active MM, and tended to be larger than and closely correlated with the FVIII-RA areas. Numerous mast cells were found in the bone marrow of active MM patients, and counts were strictly correlated with the microvessel density. The conditioned medium (CM) of bone marrow plasma cells from active MM patients stimulated endothelial cell proliferation and chemotaxis, monocyte chemotaxis, and angiogenesis in vivo (assessed by the chick embryo chorioallantoic membrane [CAM] system) more strongly and frequently than the CM of patients with nonactive MM and MGUS. Immunoassay of plasma cell lysates gave significantly higher levels of fibroblast growth factor-2 (FGF-2) in patients with active MM than in the other two groups, and a neutralizing anti-FGF-2 antibody inhibited by 46% to 68% the biological activity exerted by the CM in vitro and in the CAM. In situ hybridization of bone marrow plasma cells and zymography of CM showed that patients with active MM express higher levels of matrix metalloproteinase-2 (MMP-2) mRNA and protein than those with nonactive MM and MGUS, whereas MMP-9 expression and secretion overlapped in all groups. Overall data indicate that patients with active MM represent the vascular phase of plasma cell tumors that is induced, at least partly, through FGF-2 and MMP-2. Mast cells possibly contribute to the vascular phase via angiogenic factors in their secretory granules. Both angiogenesis and MMP-2 secretion can account for intramedullary and extramedullary spreading of plasma cells in patients with active MM.

Bone marrow angiogenesis in patients with active multiple myeloma

Bone marrow angiogenesis in patients with active multiple myeloma

Bone marrow angiogenesis in patients achieving complete response after stem cell transplantation for multiple myeloma.

Although most of the initial studies in angiogenesis were done on solid tumors, there is now data suggesting the importance of angiogenesis in hematologic malignancies. We estimated bone marrow microvessel density before autologous stem cell transplantation and at the time of response in 13 patients with myeloma (seven complete and six partial responders) using an immunohistochemical stain for factor VIII-related antigen (von Willebrand factor). Baseline microvessel density was significantly different between bone marrow samples from patients with myeloma and morphologically normal, staging marrows from patients with limited stage Hodgkin's disease, mean (+/- s.d.) 294 (+/-115)/mm2 vs 93 (+/-26/mm2, respectively, P = 0.001. After transplantation, microvessel density continued to be high in myeloma samples compared to samples from control patients with limited stage Hodgkin's disease, mean (+/- s.d.) 230 (+/-68)/mm2, P = 0.003. There was no difference in microvessel density at the time of complete or partial response compared to values prior to transplantation. This report confirms that increased angiogenesis is found in myeloma bone marrow prior to transplantation, and suggests that increased angiogenesis persists even after complete response.

Angiogenesis in B cell lymphoproliferative diseases. Biological and clinical studies.

Angiogenesis is a necessary step in solid tumor progression (growth, invasion and metastasis) with which it correlates and is indicative of an unfavourable prognosis. We observed bone marrow angiogenesis in patients with active multiple myeloma (MM), though not in patients with non-active MM nor with monoclonal gammopathies of undetermined significance (MGUS). Microvessel density increased in parallel with the labeling index (LI%)--an indicator of plasma cell proliferating activity that correlates with prognosis--and defined a risk of MM progression in much the same way as LI% itself. Consequently, bone marrow angiogenesis could be an indication for unfavourable prognosis in MGUS and MM. Angiogenesis has also been demonstrated in lymph nodes involved by B cell non Hodgkin's lymphoma (B-NHL) belonging to the Working Formulation intermediate-grade (diffuse subtypes), and high-grade categories, but not in the low-grade and intermediate-grade (follicular subtype) categories. It correlated with the B-NHL cell proliferating activity, since large increments in this activity have already been demonstrated in intermediate- and high-grade vs low-grade tumors. Active MM, intermediate-grade, diffuse subtypes, and high-grade B-NHLs correspond to the vascular phases of B cell lymphoproliferative diseases, and could thus be assimilated to locally invasive and metastatic solid tumors. Similarly to solid tumors during these stages of progression, tumor B cells are also capable of inducing angiogenesis, both directly and indirectly by activating the inflammation infiltrate--a possibility that was first demonstrated by means of B-NHL implants onto the chick embryo chorioallantoic membrane. Anti-angiogenic therapy can be envisaged as a possible future development.