Serum concentrations of DKK-1 correlate with the extent of bone disease in patients with multiple myeloma

Objectives: Lytic bone disease is a hallmark of multiple myeloma (MM) and is caused by osteoclast activation and osteoblast inhibition. Secretion of Dickkopf (DKK)‐1 by myeloma cells is a major factor which causes inhibition of osteoblast precursors. So far, there is no study showing a significant difference in serum DKK‐1 levels in MM patients with or without lytic bone lesions. Methods: DKK‐1 serum levels were quantified in 184 untreated MM patients and 33 monoclonal gammopathy of undetermined significance (MGUS) patients by ELISA, using a monoclonal anti‐DKK‐1 antibody. Results: Serum DKK‐1 was elevated in MM as compared with MGUS (mean 11 963 pg/mL vs. 1993 pg/mL; P < 0.05). Serum DKK‐1 levels significantly correlated with myeloma stage according to Durie and Salmon (mean 2223 pg/mL vs. 15 209 pg/mL in stage I and II/III, respectively; P = 0.005). Importantly, myeloma patients without lytic lesions in conventional radiography had significantly lower DKK‐1 levels than patients with lytic bone disease (mean 3114 pg/mL vs. 17 915 pg/mL; P = 0.003). Of interest, serum DKK‐1 correlated with the number of bone lesions (0 vs. 1–3 vs. >3 lesions: 3114 pg/mL vs. 3559 pg/mL vs. 24 068 pg/mL; P = 0.002). Conclusion: Using a large series of myeloma patients, we could show for the first time a correlation between DKK‐1 serum concentration and the amount of lytic bone disease, indicating that DKK‐1 is an important factor for the extent of bone disease and supporting the hypothesis of DKK‐1 as a therapeutic target in myeloma bone disease.     

High serum YKL-40 concentration is associated with severe bone disease in newly diagnosed multiple myeloma patients

Objectives: In multiple myeloma (MM) YKL‐40 is present in the bone marrow microenvironment and is suggested to play a role in remodelling of the extracellular matrix. Here, the association between serum YKL‐40 and severity of bone disease in MM is investigated. Methods: Serum YKL‐40 was measured in 34 MM patients at diagnosis. Bone disease was assessed by radiography and biochemical markers of bone metabolism. Patients were treated with conventional chemotherapy and followed for up to 30 months. Results: Patients with a serum YKL‐40 elevated above the age specific reference range (56%) had a higher total X‐ray score (P = 0.003) and higher levels of the markers of bone resorption serum C‐terminal telopeptide of collagen type I (P = 0.003), urine pyridinoline (P = 0.04) and urine deoxypyridinoline (P = 0.002), while the levels of urine N‐terminal telopeptide of collagen type I (NTX‐1) and the markers of bone formation equalled those seen in patients with a normal serum YKL‐40. Serum YKL‐40 level (β = 7.6; P = 0.002) and urine NTX‐1 (log₂) (β = 3.5; P = 0.006) were independent predictors of total X‐ray score at diagnosis. Patients with elevated serum YKL‐40 at diagnosis had shorter time to first osteolytic event compared to patients with normal serum YKL‐40 (12 months vs. not reached; Log rank test: P = 0.03). Conclusions: Newly diagnosed MM patients with elevated serum concentrations of YKL‐40 have more severe bone destruction including increased bone resorptive activity and shorter time to progression of bone disease. At this point, a potential role for YKL‐40 in myeloma‐related bone disease must be considered.     

Diagnostic value of serum IL-6 level in monoclonal gammopathies

Summary. The serum level of IL-6 was reported to reflect disease severity in patients with multiple myeloma. We used a specific radioimmunoassay to measure the level of IL-6 in 239 serum samples in which a monoclonal gammopathy was identified for the first time. The same sample was used for the measurement of serum C reactive protein and serum albumin. Then, an inventory of clinical and biological features allowed us to classify these patients into five groups: monoclonal gammopathy of undetermined significance (MGUS: 128), multiple myeloma (MM:66), Waldenström's macroglobulinaemia (WM:27), non-Hodgkin's lymphoma (NHL: 11) and chronic lymphocytic leukaemia (CLL: 7). The number of patients with serum IL-6 (S-IL-6) level >0.335 ng/ml (upper limit in normal sera) was significantly higher in the MM group (35%; Confidence Interval (CI) 23.5–46.5) compared with the MGUS group (15%; CI 8.8–21.2). The distribution of S-IL-6 levels was also significantly different between the groups (Mann-Whitney test: P< 0.01). High S-IL-6 levels were measured in 5/11 patients with NHL and 9/27 patients with WM. The distribution of S-IL-6 levels in these groups was the same as that in MGUS or MM groups. In patients with MM, elevated S-IL-6 levels were associated with haemoglobin level <100 g/l (P< 0.005). bone marrow plasmocytosis >50% (P<0.05) and stages II and III in the Durie & Salmon staging system (P< 0.005). The S-IL-6 level was also related to light chain component excretion in urine (P<0.01) and M component serum level for IgA (P<0.01). In patients with MGUS, the S-IL-6 level correlated with serum CRP level (P<0.05). serum lactate dehydrogenase (P< 0.05) and serum ferritin (P < 0.01). We conclude that the S-IL-6 level is a marker of high tumour burden in multiple myeloma. However, S-IL-6 level can be increased in patients with MGUS in relation to inflammatory parameters. Therefore the S-IL-6 level does not demonstrate high predictive value for the diagnosis of MM in patients with newly identified monoclonal gammopathy.     

Abnormal bone turnover in monoclonal gammopathy of undetermined significance: analyses of type I collagen telopeptide,osteocalcin, bone-specific alkaline phosphatase and propeptides of type I and type III procollagens

Abstract: The main difference between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) is the presence of lytic bone destructions in the latter. About 20% of MGUS patients develop MM, and histomorphometric studies have shown disturbed bone turnover rates in some of these patients. This study was performed in order to evaluate whether serum analyses of the C-terminal telopeptide of type I collagen (ICTP), as a reflector of bone degradation, and of osteocalcin, bone-specific alkaline phosphatase (bAP) and the C-terminal propeptide of type I procollagen (PICP), as markers of bone formation, might give information on disturbancies of bone metabolism in MGUS. Furthermore, serum N-terminal propeptide of procollagen III (PIIINP) might give information on disturbances in collagen III metabolism in the bone marrow. In the 35 patients examined, serum ICTP was elevated in 12 patients (34%), serum PIIINP elevated in 6 patients (17%), serum osteocalcin elevated in 11 patients (31%), serum bAP elevated in 6 patients (17%), and serum PICP elevated in 4 patients (11%). Serum ICTP correlated significantly with PIIINP (r=0.72, p<0.001), and with serum osteocalcin (r=0.57, p<0.001) and serum bAP (r=0.51, p=0.002). These findings indicate disturbancies of bone turnover and affected collagen metabolism in some MGUS patients. Follow-up observation may reveal any prognostic value of these findings.     

Renal plasma clearance: A valuable marker in myelomatosis

Summary Forty-two consecutive patients with untreated myelomatosis (MM) formed the basis of settling the validity of measuring the renal plasma clearance (RPC), either indirectly using the serum creatinine or directly using the glomerular filtration rate (GFR) when studying anaemia, calcium metabolism, proteins in serum and urine, and prognosis. Patients without light chain excretion in the urine had a higher GFR (P<0.01) than patients with light chain excretion. The haemoglobin concentration (Hb) was strongly correlated (P<0.001) to both, serum creatinine and GFR. Patients with normal serum concentrations of the physiological immunoglobulins had higher Hb (P<0.01) than patients with reduced serum immunoglobulins. Patients with serum calcium >3.00 mmol/l had additional reduced GFR compared with the other myeloma patients. The serum parathyroid hormone was decreased (P<0.01) and inversely correlated to the GFR. Patients with increased serum creatinine, reduced GFR or with osteolytic bone lesions had a decreased survival rate. The study shows that the major factor in prediction of Hb and prognosis in patients with MM is the RPC expressed either as the serum creatinine or the GFR. In addition, the significant correlations between the GFR and the other variables in MM assessed the RPC to be a useful and valuable marker in studies of anaemia, protein and calcium metabolism and prognosis in MM.Supported by grants from the Danish Medical Research Council     

Serum B-cell maturation antigen is elevated in multiple myeloma and correlates with disease status and survival

Although TNFRSF17 (also designated as B‐cell maturation antigen (BCMA)) is expressed on tumour cells in B‐cell malignancies, it has not been found in serum. The present study found that BCMA concentrations were higher in the supernatants of cultured bone marrow mononuclear cells from multiple myeloma (MM) patients than in healthy subjects. Serum BCMA levels were measured in samples from MM patients (n = 209), monoclonal gammopathy of undetermined significance (MGUS) individuals (n = 23) and age‐matched controls (n = 40). BCMA was detected in the serum of untreated MM patients (n = 50) and levels were higher than in MGUS patients (P = 0·0157) and healthy subjects (P < 0·0001). Serum BCMA levels were higher among patients with progressive disease (n = 80) compared to those with responsive disease (n = 79; P = 0·0038). Among all MM patients, overall survival was shorter among patients whose serum BCMA levels were above the median (P = 0·001). We also demonstrated that sera from mice with human MM xenografts contained human BCMA, and levels correlated with the change in tumour volume in response to melphalan or cyclophosphamide with bortezomib. These results suggest that serum BCMA levels may be a new biomarker for monitoring disease status and overall survival of MM patients.     

The prognostic value of diagnosing concurrent multiple myeloma in immunoglobulin light chain amyloidosis

The prevalence and prognostic value of a concomitant diagnosis of symptomatic or asymptomatic multiple myeloma (MM), as defined by the current International Myeloma Working Group (IMWG) criteria, in patients with immunoglobulin light chain amyloidosis (AL), are unknown. We studied 46 consecutive patients with AL who underwent quantification of serum M‐protein and clonal bone marrow plasma cells, as well as a comprehensive evaluation for end organ damage by MM. Using standard morphology and CD138 immunohistochemical staining, 57% and 80% of patients were found to have concomitant MM, respectively. Nine patients exhibited end organ damage consistent with a diagnosis of symptomatic MM. While overall survival was similar between AL patients with or without concurrent myeloma (1‐year overall survival 68% vs. 87%; P = 0·27), a diagnosis of symptomatic myeloma was associated with inferior outcome (1‐year overall survival 39% vs. 81%; P = 0·005). Quantification of bone marrow plasma cells by both standard morphology and CD138 immunohistochemistry identified a much higher prevalence of concurrent MM in patients with AL than previously reported. Evaluation of bone marrow plasma cell infiltration and presence of myeloma associated end organ damage could be clinically useful for prognostication of patients with AL.     

The effect of the dual PI3K and mTOR inhibitor BEZ235 on tumour growth and osteolytic bone disease in multiple myeloma

The plasma cell malignancy multiple myeloma (MM) is unique among haematological malignancies in its capacity to cause osteoclast‐mediated skeletal destruction. The PI3K/Akt/mTOR pathway mediates proliferation, survival and drug resistance in MM plasma cells and is also involved in regulating the formation and activity of bone‐forming osteoblasts and bone‐resorbing osteoclasts. NVP‐BEZ235 is a dual pan class I PI3K and mTOR inhibitor that is currently undergoing clinical evaluation in several tumour settings. In this study, we examined the anti‐tumorigenic effects of BEZ235 in an immunocompetent mouse model of MM and assessed the effects of BEZ235 on osteoblast and osteoclast formation and function. BEZ235 treatment (50 mg/kg) resulted in a significant decrease in serum paraprotein and tumour burden, and μCT analysis of the proximal tibia revealed a significant reduction in the number of osteolytic bone lesions in BEZ235‐treated animals. Levels of the serum osteoblast marker P1NP were significantly higher in BEZ235‐treated animals, while levels of the osteoclast marker TRAcP5 were reduced. In vitro, BEZ235 decreased MM plasma cell proliferation, osteoclast formation and function and promoted osteoblast formation and function. These findings suggest that, in addition to its anti‐tumour properties, BEZ235 could be useful in treating osteolytic bone disease in MM patients.     

Interphase fluorescence in situ hybridization identifies chromosomal abnormalities in plasma cells from patients with monoclonal gammopathy of undetermined significance

Karyotypic studies in patients with monoclonal gammopathy of undetermined significance (MGUS) have been hampered by a low percentage of bone marrow plasma cells (BMPC), which are predominantly nonproliferating. By combining cytomorphology and interphase fluorescence in situ hybridization (FISH) we investigated whether or not chromosomal abnormalities occur in BMPC from patients with MGUS. Studying chromosomes 3, 7, 11, and 18, which we found to be frequently aneuploid by FISH in multiple myeloma (MM), we observed three hybridization signals for one of these chromosomes 3 were most common, occurring in 38.9% of patients, followed by gains of chromosomes 11 (25%), 7 (16.7%), and 18 (5.6%) Among BMPC, the frequency of aneuploid cells was 18.9% +/- 13.9% (mean +/- SD) for chromosome 3, 22.3% +/- 9.2% for chromosome 11, 23.2% +/- 22.0% for chromosome 7, and 6.1% +/- 2.3% for chromosome 18. In five patients, chromosomal abnormalities were shown to be restricted to BMPC expressing cytoplasmic immunoglobulins corresponding to the serum paraprotein. No gain of hybridization signals was observed in normal and reactive plasma cells. In one patient with MGUS, metaphase cytogenetics revealed one abnormal metaphase with 47, XY, +4, and trisomy 4 was also demonstrated in a subpopulation of BMPC by interphase FISH. FISH results from patients with MGUS and newly diagnosed MM at stage IA (n = 14) indicated that aberrations involving > or = 2 chromosomes occurred significantly more often in early stage MM (P < .01). With respect to clinical and laboratory features, MGUS patients with and without chromosomal abnormalities were indistinguishable. Our results indicate that MGUS already has the chromosomal characteristics of a plasma cell malignancy.     

Clinical significance of elevated soluble interleukin-6 receptor levels in the sera of patients with plasma cell dyscrasias

Summary .We investigated the clinical significance of the serum soluble interleukin-6 receptor (sIL-6R) in 42 patients with plasma cell dyscrasias (27 with multiple myeloma (MM), 13 with monoclonal gammopathy of undetermined significance (MGUS), and two with plasma cell leukaemia (PCL)). Serum levels of sIL-6R in normal individuals were 77 ± 21 ng/ml (mean ± SD, n = 18); those in patients with MGUS and with MM were elevated (102 ± 33 ng/ml, mean ± SD, P < 0–05 and 126 ± 60ng/ml, mean ± SD, P < 0–01, respectively). Significant correlations were not found between the serum levels of sIL-6R and known prognostic factors (C-reactive protein, haemoglobin levels, calcium, creatinine, β₂-microglobulin, amounts of M-protein, or percentages of plasma cells in bone marrow). Elevated serum sIL-6R did not affect the survival of the patients with MM. Serial measurements of sIL-6R together with the clinical course of patients with plasma cell neoplasias revealed a good correlation between the sIL-6R level and disease activity. We conclude that sIL-6R can be used as a clinical factor correlated with the disease activity, at least in some patients with plasma cell neoplasias.     

Acquired von Willebrand syndrome in multiple myeloma

Abstract

Acquired von Willebrand syndrome (AvWS) is an uncommon complication of multiple myeloma (MM), and it is believed to be connected with paraprotein. The aim of this study was to determine the incidence of AvWS in patients with MM, and estimate the role of paraprotein in its occurrence. The study included 40 patients with MM. The plasma level of paraprotein, platelet adhesion on glass pearls, plasma von Willebrand factor antigen concentration, and ristocetin-induced platelet aggregation (RIPA) were measured initially. Absence of RIPA was found in six patients with MM (15%); however, all six of them had normal levels of von Willebrand factor antigen. Paraprotein was isolated from the serum of these patients. Platelet aggregation was measured in six healthy donors before and after addition of the isolated paraprotein. RIPA was significantly decreased in healthy donors in the presence of paraprotein (P<0·001). The same test was repeated with added human immunoglobulins for intravenous use without any change in RIPA. A significant negative correlation between plasma paraprotein level and RIPA was found (P<0·001). These investigations have shown that paraprotein is associated with AvWS in patients with MM.     

Clinical relevance of soluble HLA class I molecules in Waldenstrom Macroglobulinemia

Objectives: Waldenstrom Macroglobulinemia (WM) is a B‐cell neoplasm characterised by secretion of IgM by lymphoplasmacytic bone marrow cells and by cytopenias and hypogammaglobulinemia in a subset of patients. Beta‐2 microglobulin (b2m) is a major prognostic factor in WM and the heavy chain of HLA class I molecules, which are known to have immunosuppressive properties and have been implicated in the pathogeny of several malignancies. Methods: We assessed the serum levels of the total soluble HLA‐I molecules and the HLA‐Gs molecules in 105 patients with IgM‐related disorders [WM (n = 42) and IgM MGUS (n = 63)], and compared the results to 41 healthy subjects. Results: We found higher levels of HLA‐Is in WM, compared to IgM MGUS and healthy donors. HLA‐Gs levels were similar in WM and in IgM MGUS, but higher than in healthy donors. The association between HLA‐Is at the cut‐off of 1.8 μg/mL and known markers of poor prognosis was then evaluated among WM patients using univariate and multivariate methods. Based on this, high HLA‐Is level was strongly associated with high serum β2M level >3 mg/L [OR = 2, (CI 95% 1.1–5.7); P = 0.04], age > 65 yrs [OR = 1.5, (CI 95% 0.5–4.1), P = 0.06] and haemoglobin ≤11.5 g/dL [OR = 3.3, (CI 95% 1.2–9.7); P = 0.03]. High levels of serum HLA‐Is were also found in patients with cryoglobulinemia, however irrespectively of WM or IgM‐MGUS status. Conclusion: Together our results suggest a possible role for soluble MHC class I molecules in WM disease. Further investigations are necessary to further demonstrate the prognostic impact of soluble MHC class I molecules in Waldenstrom Macroglobulinemia.     

Differentiation of monoclonal gammopathy of undetermined significance and multiple myeloma using flow cytometric characteristics of plasma cells

BACKGROUND AND OBJECTIVES: The differential diagnosis between multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) may be uncertain in some cases; this problem is reflected by discrepancies between different classification systems with an accordance in only 2/3 of cases. We studied whether flow-cytometric characteristics of plasma cells (PC) can be used for the differentiation between MGUS and MM. DESIGN AND METHODS: Patients were divided into 3 groups: Group A included 13 myeloma patients with a plasma cell infiltration of the bone marrow of 10-30%, serum M-protein < or = 3.5 g/dL (IgG) or < or = 2 g/dl (IgA) and without bone lesions in conventional radiography. Group B consisted of 53 patients who fulfilled the Durie and Salmon diagnostic criteria including at least one major criterion, and group C individuals with MGUS (n=17). The ratio of immunophenotypically normal (i.e. CD19(+)/CD56(-)) to all bone marrow plasma cells (BMPC), the number of peripheral blood PC (PBPC), the percentage of BMPC in S-phase and the DNA content of BMPC were analyzed. RESULTS: All individuals with MGUS and no patient with MM in group A or group B had a ratio of phenotypically normal to all BMPC > or = 20%. The median of monoclonal PBPC was 0/microL (range 0-2/ microL) in MGUS, 1/microL (range 0-30/microL) in MM group A and 2.4/microL (range 0-211/microL) in MM group B. The median percentage of BMPC in S-phase was 1.6% both in MGUS and in group A and 3% in group B. Aneuploidy was found in 12%, 11% and 41% in MGUS, group A and group B, respectively. INTERPRETATION AND CONCLUSIONS: The ratio of immunophenotypically normal to all BMPC was the only flow-cytometric parameter for the differentiation of MGUS and MM group A (p<0.0005). The other parameters were significantly different between MGUS and MM group B, but not group A.     

Nestin expression throughout multistep pathogenesis of multiple myeloma

The stem cell marker nestin (NES) is found in dividing cells of developing and regenerating tissues. Upon terminal differentiation, NES expression is diminished but may be re‐expressed following injury or in cancer. Surprisingly, we recently confirmed NES as a tumour‐specific marker for mature CD138⁺38⁺ plasma cells (PC) in multiple myeloma (MM). The present study analysed NES expression throughout the spectrum of MM developmental stages, starting with individuals with no haematological malignancy, through monoclonal gammopathy of undetermined significance (MGUS) and MM to plasma cell leukaemia (PCL) and MM cell lines. NES was analysed in bone marrow PC of 163 MM, four PCL and nine MGUS patients, 10 individuals with no haematological malignancy and 6 myeloma cell lines (OPM‐2, RPMI‐8226, MOLP‐8, U‐266, EJM, NCI‐H929) by flow cytometry and/or real‐time polymerase chain reaction or immunochemistry. We observed a tendency of increased NES expression in parallel with disease progression. NES was evaluated as a reliable marker for accurate discrimination between MM patients and the control group. High NES levels were strongly associated with the presence of 1q21 gain. For the first time, NES was demonstrated to predict worse response to conventional therapy/novel agents. These results suggest that NES might become a useful clinical parameter with an important role in MM pathogenesis.     

Genomewide profiling of copy‐number alteration in monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a benign condition with an approximate 1% annual risk of symptomatic plasma cell disorder development, mostly to multiple myeloma (MM). We performed genomewide screening of copy‐number alterations (CNAs) in 90 MGUS and 33 MM patients using high‐density DNA microarrays. We identified CNAs in a smaller proportion of MGUS (65.6%) than in MM (100.0%, P = 1.31 × 10^?5) and showed median number of CNAs is lower in MGUS (3, range 0–22) than in MM (13, range 4–38, P = 1.82 × 10^?10). In the MGUS cohort, the most frequent losses were located at 1p (5.6%), 6q (6.7%), 13q (30.0%), 14q (14.4%), 16q (8.9%), 21q (5.6%), and gains at 1q (23.3%), 2p (6.7%), 6p (13.3%), and Xq (7.8%). Hyperdiploidy was detected in 38.9% of MGUS cases, and the most frequent whole chromosome gains were 3 (25.6%), 5 (23.3%), 9 (37.8%), 15 (23.3%), and 19 (32.2%). We also identified CNAs such as 1p, 6q, 8p, 12p, 13q, 16q losses, 1q gain and hypodiploidy, which are potentially associated with an adverse prognosis in MGUS. In summary, we showed that MGUS is similar to MM in that it is a genetically heterogeneous disorder, but overall cytogenetic instability is lower than in MM, which confirms that genetic abnormalities play important role in monoclonal gammopathies.     

Circulating monotypic B-cells in multiple myeloma: association with lambda paraproteins

The peripheral blood and bone marrow mononuclear cell immunophenotype was investigated in series of 41 patients with plasma cell dyscrasias (29 with multiple myeloma and 12 with monoclonal gammopathy of undetermined significance (MGUS) or solitary plasmacytoma). A statistically significant relationship between the presence of monotypic B-cells (MBC) in the peripheral blood and the paraprotein light chain isotype was found in the myeloma patients (P = 0.0025). MBCs were documented in 71% of patients with lambda paraproteins, compared with only 13% of patients with kappa paraproteins. The difference in MBC was independent of disease stage as well as of individual prognosticators such as haemoglobin, renal function, paraprotein size and beta-2-microglobulin, although lambda producers had significantly higher calcium levels than patients with kappa paraproteins (P = 0.03). A similar trend was also noted for MBC to be found more commonly in patients with lambda producing MGUS and solitary plasmacytoma. This phenomenon may account for the worse prognosis in patients with lambda paraproteins. In our hands, immunophenotypic detection of peripheral blood involvement in plasma cell dyscrasias is more sensitive than investigation of karyotype or immunoglobulin gene rearrangements.     

Immunoparesis and monoclonal gammopathy of undetermined significance are disassociated in advanced age

Immunoparesis and a skewed serum free light chain (FLC) ratio are indicators of immune dysfunction predictive of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). Previous studies have reported increased prevalence of MGUS by age, but no study has examined the relationship between immunoparesis and abnormal FLC ratios in the elderly. We screened 453 older adults (median age, 80 years; range, 65–96) to characterize the patterns of immunoparesis and abnormal FLC ratio in relation to MGUS. We defined MGUS in 4.4% of the subjects; the prevalence was 12.5% among individuals of >90 years. In MGUS (vs. non‐MGUS) cases, immunoparesis and abnormal FLC ratios were detected in 70.0% (vs. 49.0%; P = 0.07) and 50.0% (vs. 12.9%; P = 0.0001), respectively. Based on small numbers, MGUS patients with abnormal FLC ratio were borderline (P = 0.07) more likely to have immunoparesis. Overall, the prevalence of immunoparesis varied in a nonlinear fashion, with lowest frequencies in the youngest and oldest groups. Our observed disassociation between MGUS prevalence and impaired immunoglobulin production suggests that separate mechanisms are involved in the development of MGUS and immunoparesis in advanced age. These findings emphasize the need for molecularly defined methods to characterize myeloma precursor states and better predict progression to MM. Am. J. Hematol. 88:89–92, 2013. © 2012 Wiley Periodicals, Inc.     

Relationships between dimethylarginine and the presence of vertebral fractures in type 2 diabetes mellitus

Objective Although previous studies suggested that nitric oxide (NO) could affect bone metabolism, little is known about whether asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, is associated with the risk of osteoporotic fractures. Methods A cross‐sectional study was carried out to examine the associations of serum dimethylarginines with bone mineral density (BMD), bone turnover markers, and the presence of vertebral fractures in 226 men and 152 postmenopausal women with type 2 diabetes. Results In subjects with vertebral fractures, there was significantly higher serum ADMA in men (0·61 ± 0·20 [mean ± SD] vs 0·55 ± 0·19 μm , P = 0·030) and symmetric dimethylarginine (SDMA) in postmenopausal women (0·72 ± 0·37 vs 0·56 ± 0·16 μm , P < 0·001) than in those without fractures. In men with vertebral fractures, serum ADMA was negatively correlated with Z‐score at one‐third radius (multiple regression β = ?0·28, p = 0·016), and SDMA was positively correlated with serum osteocalcin (β = 0·38, P = 0·044) and urinary N‐terminal cross‐linked telopeptide of type‐I collagen (β = 0·40, P = 0·027). In addition, serum ADMA in men and SDMA in postmenopausal women were positively associated with the presence of vertebral fractures after adjusting for age, duration of diabetes, and lumbar BMD (multiple logistic regression odds ratio [OR] = 1·36, P = 0·044 and OR = 1·78, P = 0 .006, respectively). Conclusions We report, for the first time, that serum dimethylarginines may be independent risk factors for prevalent vertebral fractures in patients with type 2 diabetes.