Hematological Diseases and Osteoporosis

Secondary osteoporosis is a common clinical problem faced by bone specialists, with a higher frequency in men than in women. One of several causes of secondary osteoporosis is hematological disease. There are numerous hematological diseases that can have a deleterious impact on bone health. In the literature, there is an abundance of evidence of bone involvement in patients affected by multiple myeloma, systemic mastocytosis, thalassemia, and hemophilia; some skeletal disorders are also reported in sickle cell disease. Recently, monoclonal gammopathy of undetermined significance appears to increase fracture risk, predominantly in male subjects. The pathogenetic mechanisms responsible for these bone loss effects have not yet been completely clarified. Many soluble factors, in particular cytokines that regulate bone metabolism, appear to play an important role. An integrated approach to these hematological diseases, with the help of a bone specialist, could reduce the bone fracture rate and improve the quality of life of these patients.

Deficient invariant natural killer T cells had impaired regulation on osteoclastogenesis in myeloma bone disease

Recent research showed that invariant natural killer T (iNKT) cells take part in the regulation of osteoclastogenesis. While the role of iNKT cells in myeloma bone disease (MBD) remains unclear. In our study, the quantity of iNKT cells and the levels of cytokines produced by them were measured by flow cytometry. iNKT cells and osteoclasts were induced from peripheral blood mononuclear cells after activation by α‐GalCer or RANKL in vitro. Then, gene expressions and the levels of cytokines were determined by RT‐PCR and ELISA, respectively. The results showed that the quantity of iNKT and production of IFN‐γ by iNKT cells were significantly decreased in newly diagnosed MM (NDMM), and both negatively related with severity of bone disease. Then, the osteoclasts from healthy controls were cultured in vitro and were found to be down‐regulated after α‐GalCer‐stimulated, while there was no significant change with or without α‐GalCer in NDMM patients, indicating that the regulation of osteoclastogenesis by iNKT cells was impaired. Furthermore, the inhibition of osteoclastogenesis by iNKT cells was regulated by IFN‐γ production, which down‐regulated osteoclast‐associated genes. In conclusion, the role of α‐GalCer‐stimulated iNKT cells in regulation of osteoclastogenesis was impaired in MBD, as a result of iNKT cell dysfunction.

A role for bone turnover markers β-CrossLaps (CTX) and amino-terminal propeptide of type I collagen (PINP) as potential indicators for disease progression from MGUS to multiple myeloma

Multiple myeloma (MM) is characterized by bone lesions arising due to unbalanced bone remodeling. Changes in the bone formation marker amino-terminal propeptide of type I collagen (PINP) and the bone resorption marker β-CrossLaps (CTX) reflect physiologic bone turnover. Whether PINP and CTX have a role in disease progression from monoclonal gammopathy of undetermined significance (MGUS) to MM is unknown. In this cross-sectional follow-up study, 241 patients with MM or MGUS were included. Serum levels of PINP and CTX were significantly higher in MM patients compared to MGUS. Moreover, increasing concentrations of PINP and CTX were observed in those MGUS patients progressing to MM, whereas PINP and CTX levels remained unchanged in MGUS patients with stable disease. In conclusion, these data indicate a potential role of PINP and CTX as biomarkers for the progression of MGUS to MM.

Advanced Imaging of Multiple Myeloma Bone Disease

Multiple myeloma (MM), a malignancy of mature plasma cells, is the second most common hematologic malignancy and the most frequent cancer to involve the skeleton (1, 2). Bone disease in MM patients is characterized by lytic bone lesions that can result in pathologic fractures and severe pain. While recent advances in MM therapy have significantly increased the median survival of newly diagnosed patients (3), skeletal lesions and their sequelae continue to be a major source of patient morbidity and mortality and bone pain is the most frequent presenting symptom of MM patients (4). Rapid improvements in imaging technology now allow physicians to identify ever smaller skeletal and bone marrow abnormalities, however the clinical value of subtle radiographic findings is not always clear. This review summarizes currently available technologies for assessing MM bone disease and provides guidance for how to choose between imaging modalities.

Bone disease in monoclonal gammopathy of undetermined significance: results from a screened population-based study

Previous studies have shown that individuals with monoclonal gammopathy of undetermined significance (MGUS) have an increased risk of fractures, although the underlying mechanisms remain unknown. Our aim was to analyze bone mineral density (BMD), bone volume, and risk of fractures among individuals with MGUS. We performed a screening using the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study cohort, consisting of 5764 elderly individuals, identifying 300 individuals with MGUS, and 275 with light-chain MGUS. Quantitative computerized tomography was performed in the lumbar spine and hip to evaluate BMD and bone geometry. Analysis of variance and the Tukey honest significance test were used to compare the groups. Hospital records were used to record fractures, with a mean follow-up of 6.9 years. Cox proportional hazard was used to compare fracture risk. No difference was found in BMD between subjects with MGUS and others in the spine (P = .34) or in total hip (P = .30). Individuals with MGUS had a significant increase in bone volume compared with others in the spine (P < .001) and total hip (P < .001). Overall, the risk of fractures was not significantly increased in individuals with MGUS (hazard ratio [HR], 1.19; 95% confidence interval [CI], 0.94-1.50). Men with MGUS had a significantly increased fracture risk, compared with other men (HR, 1.46; 95% CI, 1.03-2.08). Our results show that although individuals with MGUS do not have decreased BMD, bone volume is increased, and MGUS men have a 50% increased fracture risk. These results indicate that bone disease and fractures in MGUS differ from processes known from osteoporosis.

Clinical significance of osteoblast precursors and osteoclast precursors in earlier diagnosis and monitoring of myeloma bone disease

Bone disease is the most common complication of multiple myeloma (MM). In order to diagnose and monitor the bone damages earlier, we detected circulating osteoclast precursors (OCPs) and osteoblast precursors (OBPs) by flow cytometry, comparing with special biochemical markers, such as tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), carboxy-terminal cross-linking telopeptide of type I collagen (CTX), osteocalcin (OCN), and procollagen I amino-terminal propeptide (PINP). The results showed that the circulating OBPs in the newly diagnosed MM patients significantly decreased compared with the normal controls (7.14 vs 12.82 %, P = 0.045), while circulating OCPs in the newly diagnosed patients and remission patients were significantly increased than the normal controls (2.46 vs 0.17 %, P = 0.000; 1.87 vs 0.17 %, P = 0.000, respectively). According to X-ray, newly diagnosed patients were divided into stages A and B (without and with osteolytic lesions). Compared with the normal controls, the circulating OBPs in stages A and B reduced (12.82 vs 7.47 %, P = 0.041; 12.82 vs 7.14 %, P = 0.010, respectively), while the circulating OCPs elevated (0.17 vs 2.31 %, P=0.010; 0.17 % vs 2.71 %, P=0.001, respectively). The levels of TRACP-5b and CTX in the newly diagnosed patients were higher than the normal controls (P = 0.014, P = 0.037) and remission patients (P = 0.025, P = 0.003), and they were significantly higher in stage B than the normal controls (P = 0.015, P = 0.002). However, the PINP and OCN levels had no significant changes in different stages. In conclusion, abnormal circulating OBPs and OCPs were found earlier before X-ray in MM and still existed in remission patients, indicating that they may be novel predictive markers for early diagnosing and monitoring bone disease.

B-Cell Disorders and Curcumin

Clinical studies with patients with early hematological malignancies (ie, monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or stage 0/1 chronic lymphocytic leukemia) suggest that early intervention with curcumin, derived from the spice turmeric, may lead to prolonged survival and delay in progressive disease in some of these patients.

The role of the bone microenvironment in skeletal metastasis

The bone microenvironment provides a fertile soil for cancer cells. It is therefore not surprising that the skeleton is a frequent site of cancer metastasis. It is believed that reciprocal interactions between tumour and bone cells, known as the “vicious cycle of bone metastasis” support the establishment and orchestrate the expansion of malignant cancers in bone. While the full range of molecular mechanisms of cancer metastasis to bone remain to be elucidated, recent research has deepened our understanding of the cell-mediated processes that may be involved in cancer cell survival and growth in bone. This review aims to address the importance of the bone microenvironment in skeletal cancer metastasis and discusses potential therapeutic implications of novel insights.

Monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, and curcumin: a randomized, double-blind placebo-controlled cross-over 4g study and an open-label 8g extension study

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) represent useful models for studying multiple myeloma precursor disease, and for developing early intervention strategies. Administering a 4g dose of curcumin, we performed a randomised, double-blind placebo-controlled cross-over study, followed by an open-label extension study using an 8g dose to assess the effect of curcumin on FLC response and bone turnover in patients with MGUS and SMM. 36 patients (19 MGUS and 17 SMM) were randomised into two groups: one received 4g curcumin and the other 4g placebo, crossing over at 3 months. At completion of the 4g arm, all patients were given the option of entering an open-label, 8g dose extension study. Blood and urine samples were collected at specified intervals for specific marker analyses. Group values are expressed as mean ± 1 SD. Data from different time intervals within groups were compared using Student's paired t-test. 25 patients completed the 4g cross-over study and 18 the 8g extension study. Curcumin therapy decreased the free light-chain ratio (rFLC), reduced the difference between clonal and nonclonal light-chain (dFLC) and involved free light-chain (iFLC). uDPYD, a marker of bone resorption, decreased in the curcumin arm and increased on the placebo arm. Serum creatinine levels tended to diminish on curcumin therapy. These findings suggest that curcumin might have the potential to slow the disease process in patients with MGUS and SMM.

Bone disease in multiple myeloma and precursor disease: novel diagnostic approaches and implications on clinical management

The manifestations of bone involvement in patients with multiple myeloma (MM) can have devastating clinical effects and increase mortality. Recent studies demonstrate that patients with the precursor conditions smoldering MM (SMM) and monoclonal gammopathy of undetermined significance (MGUS) show evidence of bone disease and increased risk of fractures. The understanding of the pathogenesis of bone disease in MM has expanded in recent years. The traditional skeletal survey will probably be replaced by newer and more sensitive imaging techniques, which may have a prognostic impact and change our definition of MGUS and SMM. Bisphosphonates are recommended to prevent skeletal events in patients with MM, and have also been studied in SMM and MGUS. This article summarizes the current knowledge of bone disease in plasma cell disorders, and discusses the current standard and future role of novel imaging techniques, as well as the evidence and current guidelines for bisphosphonates in MM, SMM and MGUS.

Vitamin D deficiency promotes prostate cancer growth in bone

BACKGROUND

Vitamin D is considered as an important determinant of bone turnover as well as cancer growth. Using a murine model of bone metastasis, we investigated the effect of vitamin D deficiency on prostate cancer cell growth in bone.

METHODS

Three-week-old male nude mice were fed either normal chow (control) or a diet deficient in vitamin D. The latter diet resulted in severe hypovitaminosis D within 6 weeks. At this point of time, 5 × 10(4)  cells of the prostate cancer cell line, PC-3, were injected either into the bone marrow (tibia) or subcutaneously into soft tissues. Osteoprotegerin (OPG) was co-administered in subgroups of mice to suppress bone remodeling. Osteolytic lesions were monitored by serial X-ray, while soft tissue tumor growth was measured by caliper. All tissues were analyzed by micro-CT and histology at endpoint.

RESULTS

Bone turnover was significantly accelerated in vitamin D deficient compared to vitamin D sufficient mice from week 6 onwards. Intra-tibially implanted PC-3 cells resulted in mixed osteolytic and osteosclerotic lesion. At endpoint, osteolytic and osteosclerotic lesion areas, total tumor area, and tumor mitotic activity were all significantly increased in vitamin D deficient mice compared to controls. Regardless of diet, OPG reduced bone turnover, total tumor, and osteosclerotic area as well as tumor mitotic activity, while promoting cell apoptosis. In contrast, vitamin D deficiency did not alter tumor growth in soft tissues.

CONCLUSION

Vitamin D deficiency stimulates prostate cancer growth in bone through modulating the bone microenvironment.

A retrospective study to evaluate the work-up and follow-up of patients with monoclonal gammopathy of undetermined significance

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell proliferative disorder that transforms into multiple myeloma and other serious B-cell disorders at an approximate rate of 1% per year; these patients are also at increased risk for fractures.

PATIENTS AND METHODS

We conducted a retrospective, multicenter study of 100 patients from seven community health clinics to gain a better understanding of the work-up, follow-up, and treatment of these patients.

RESULTS

MGUS patients appear to undergo inadequate work-up, follow-up, and treatment in the community setting.

CONCLUSIONS

Physicians should adhere to recently established guidelines to ensure that MGUS patients receive optimal care for this condition.

Monoclonal gammopathy of undetermined significance and risk of skeletal fractures: a population-based study

Patients with multiple myeloma (MM) have an increased risk of fractures. On the basis of small numbers, patients with monoclonal gammopathy of undetermined significance (MGUS) have been reported to have an increased fracture risk. Using population-based data from Sweden, we assessed the risks of fractures in 5326 MGUS patients diagnosed from 1958 to 2006, compared with 20 161 matched controls. MGUS patients had an increased risk of any fracture at 5 (hazard ratio [HR] = 1.74; 95% confidence interval [CI], 1.58-1.92) and 10 (HR = 1.61; 95% CI, 1.49-1.74) years. The risk was significantly higher for axial (skull, vertebral/pelvis, and sternum/costae) compared with distal (arm and leg) fractures (P < .001). On the basis of 10 years of follow-up, there was an increased risk of vertebral/pelvic (HR = 2.37; 95% CI, 2.02-2.78), sternal/costae (HR = 1.93; 95% CI, 1.5-2.48), arm (HR = 1.23; 95% CI, 1.06-1.43), leg (HR = 1.40; 95% CI, 1.26-1.56), and other/multiple fractures (HR = 4.25; 95% CI, 3.29-5.51). Risks for fractures did not differ by isotype or M protein concentration at diagnosis. MGUS patients with (versus without) fractures had no excess risk of MM or Waldenström macroglobulinemia. Our results suggest that bone alterations are present in early myelomagenesis. Our findings may have implications for the development of better prophylaxis for bone disease in MGUS, and they provide novel clues on pathogenesis of MM bone disease.

Multiple myeloma: changes in serum C-terminal telopeptide of collagen type I and bone-specific alkaline phosphatase can be used in daily practice to detect imminent osteolysis

Objective: Monitoring of bone disease in multiple myeloma is becoming increasingly important because bone-protecting treatment with bisphosphonate is becoming restricted after the awareness of osteonecrosis of the jaw. Despite the potential of biochemical markers of bone remodeling to monitor dynamic bone turnover, they are not used in everyday practice. Here, we investigate their usefulness to detect imminent progressive osteolysis in relapsing patients with multiple myeloma. Methods: In an unselected cohort of 93 patients, we measured the bone resorption markers C-terminal telopeptide of collagen type I (CTX-I), C-terminal cross-linked telopeptide of type-I collagen generated by MMPs (ICTP), N-terminal cross-linked telopeptide of type-I collagen (NTX-I), and the bone formation marker bone-specific alkaline phosphatase (bALP) monthly for 2 yr. Retrospectively, we identified 40 cases where patients had progressive disease. We investigated how the bone markers developed prior to disease progression. Results: We observed that CTX-I and bALP changed significantly before progressive disease were recognized. More interestingly, these changes differed depending on whether concurrent progressive osteolysis was present. In patients with progressive osteolysis, there was a large increase in bone resorption which was not compensated by increased bone formation. In contrasts, patients with stable bone disease had only a slight increase in bone resorption which was compensated by concurrent increased bone formation. By calculating a patient-specific CTX-I/bALP ratio, we quantified the risk a patient experiences if the ratio increases. Conclusion: By analyzing patient-specific changes in the ratio of CTX-I/bALP, we might tailor treatment with bone-protecting agents in the individual patient.

The significance of carboxy-terminal telopeptide of type I collagen (ICTP) and osteocalcin (OC) in assessment of bone disease in patients with multiple myeloma

Bone disease occurring in multiple myeloma is usually evaluated using radiological methods. These methods, however, provide not much information about the dynamic process of bone resorption and formation. This study analysed levels of serum markers of bone turnover (ICTP and OC), reflecting function of osteoclasts and osteoblasts. It demonstrates increased level of ICTP in 75 patients with MM compared to control group (8 persons) and patients with Waldenström's macroglobulinemia (10 persons). The level of ICTP was also higher in patients with more advanced bone disease and probably in higher stage of disease according to Salmon and Durie classification. This tendency was not observed in relation to OC. Result of the research confirms that ICTP may incur sensitive and specific markers of bone lesions in multiple myeloma.

The pathogenesis of the bone disease of multiple myeloma

Multiple myeloma is a fatal hematologic malignancy associated with clonal expansion of malignant plasma cells within the bone marrow and the development of a destructive osteolytic bone disease. The principal cellular mechanisms involved in the development of myeloma bone disease are an increase in osteoclastic bone resorption, and a reduction in bone formation. Myeloma cells are found in close association with sites of active bone resorption, and the interactions between myeloma cells and other cells within the specialized bone marrow microenvironment are essential, both for tumor growth and the development of myeloma bone disease. This review discusses the many different factors which have been implicated in myeloma bone disease, including the evidence for their role in myeloma and subsequent therapeutic implications.

Stimulation of new bone formation by the proteasome inhibitor, bortezomib: implications for myeloma bone disease

Impaired bone formation contributes to the lack of bone healing in multiple myeloma and there is a need for agents with bone anabolic properties to reverse the bone deficit in patients. Bortezomib, a proteasome inhibitor with antitumour efficacy in myeloma patients, enhanced new bone formation in mouse calvarial cultures; this effect was blocked by dickkopf 1(Dkk1), an antagonist of Wnt signalling implicated in myeloma bone disease. Bortezomib inhibited Dkk1 expression in calvariae and bone marrow-derived stromal cells, suggesting a novel mechanism by which bortezomib exerts its effects in bone. Clinical trials in patients with myeloma bone disease are needed to validate these results.

Increasing Wnt signaling in the bone marrow microenvironment inhibits the development of myeloma bone disease and reduces tumor burden in bone in vivo

There is increasing evidence to suggest that the Wnt signaling pathway plays a critical role in the pathogenesis of myeloma bone disease. In the present study, we determined whether increasing Wnt signaling within the bone marrow microenvironment in myeloma counteracts development of osteolytic bone disease. C57BL/KaLwRij mice were inoculated intravenously with murine 5TGM1 myeloma cells, resulting in tumor growth in bone and development of myeloma bone disease. Lithium chloride (LiCl) treatment activated Wnt signaling in osteoblasts, inhibited myeloma bone disease, and decreased tumor burden in bone, but increased tumor growth when 5TGM1 cells were inoculated subcutaneously. Abrogation of beta-catenin activity and disruption of Wnt signaling in 5TGM1 cells by stable overexpression of a dominant-negative TCF4 prevented the LiCl-induced increase in subcutaneous growth but had no effect on LiCl-induced reduction in tumor burden within bone or on osteolysis in myeloma-bearing mice. Together, these data highlight the importance of the local microenvironment in the effect of Wnt signaling on the development of myeloma bone disease and demonstrate that, despite a direct effect to increase tumor growth at extraosseous sites, increasing Wnt signaling in the bone marrow microenvironment can prevent the development of myeloma bone disease and inhibit myeloma growth within bone in vivo.

Accelerated bone resorption, due to dietary calcium deficiency, promotes breast cancer tumor growth in bone

The skeleton is a major site of breast cancer metastases. High bone turnover increases risk of disease progression and death. However, there is no direct evidence that high bone turnover is causally associated with the establishment and progression of metastases. In this study, we investigate the effects of high bone turnover in a model of breast cancer growth in bone. Female nude mice commenced a diet containing normal (0.6%; 'Normal-Ca') or low (0.1%; 'Low-Ca') calcium content. Mice were concurrently treated with vehicle or osteoprotegerin (1 mg/kg/d s.c; n = 16 per group). Three days later (day 0), 50,000 Tx-SA cells (variant of MDA-MB-231 cells) were implanted by intratibial injection. On day 0, mice receiving Low-Ca had increased serum parathyroid hormone (PTH) and tartrate-resistant acid phosphatase 5b levels, indicating secondary hyperparathyroidism and high bone turnover, which was maintained until day 17. Osteoprotegerin increased serum PTH but profoundly reduced bone resorption. On day 17, in mice receiving Low-Ca alone, lytic lesion area, tumor area, and cancer cell proliferation increased by 43%, 24%, and 24%, respectively, compared with mice receiving Normal Ca (P < 0.01). Osteoprotegerin treatment completely inhibited lytic lesions, reduced tumor area, decreased cancer cell proliferation, and increased cancer cell apoptosis. Increased bone turnover, due to dietary calcium deficiency, promotes tumor growth in bone, independent of the action of PTH. Breast cancer patients frequently have low dietary calcium intake and high bone turnover. Treatment to correct calcium insufficiency and/or treatment with antiresorptive agents, such as osteoprotegerin, may be of benefit in the adjuvant as well as palliative setting.

Biochemical markers of bone turnover in diagnosis of myeloma bone disease

This study was designed to explore the value of markers of bone turnover, macrophage inflammatory protein-1alpha (MIP-1alpha), and osteopontin (OPN) in the diagnosis of myeloma bone disease. Twenty-five patients with newly diagnosed and untreated multiple myeloma (MM), and 22 age-, sex-, and bone mineral density-matched control subjects were enrolled. Levels of MIP-1alpha, OPN, carboxy-terminal telopeptide of Type-1 collagen (C-telopeptide or Ctx), deoxypyridinoline (DPD), Type-1 collagen propeptide (T1Pro), and bone-specific alkaline phosphatase (BALP) were assessed in both groups. Twenty-two of the patients had bone involvement documented by skeletal surveys and lumbar spinal magnetic resonance imaging. Levels of serum Ctx, OPN, MIP-1alpha, and urine DPD were significantly higher in MM patients with bone disease than in controls (P<0.01). Serum Ctx levels were elevated in 90.9% of patients with MM and 40.9% of controls (P<0.001). Urine DPD levels were elevated in 90.4% of the patients and 31.8% of the controls (P<0.001). The serum OPN and MIP-1alpha levels of the patients were significantly correlated with beta2-microglobulin and lactate dehydrogenase levels (P<0.05). Our study indicates that Ctx and DPD are sensitive markers of bone disease in MM, and higher than normal values suggest presence of bone disease rather than benign osteoporosis in MM. The utility of OPN and MIP-1alpha needs to be further investigated.

Lumbar bone mineral density as the major factor determining increased prevalence of vertebral fractures in monoclonal gammopathy of undetermined significance

The possible relationships between biochemical measurements and both densitometric and radiographic indexes of skeletal fragility were evaluated in 65 postmenopausal women with monoclonal gammopathy of undetermined significance (MGUS). There was a significantly higher prevalence of vertebral fractures in the MGUS group compared with a control population (P < or = 0.001). The MGUS patients were then grouped according to the presence or absence of at least one mild vertebral fracture. Patients with fractures (Fx, n=34) were older (62.8 +/- 6.1 years), with long-standing disease (8.8 +/- 7.1 years) when compared with those without fractures (NFx, n=31; 59.7 +/- 5.0 years, P < or = 0.05 and 5.8 +/- 4.1 years, P < or = 0.05). The receptor activator of nuclear factor kappa-B ligand/osteoprotegerin ratio was higher in Fx compared with NFx (0.092 +/- 0.018 vs. 0.082 +/- 0.020; P < or = 0.05). Lumbar spine (0.811 +/- 0.14 vs. 0.956 +/- 0.12 g/cm2), femoral neck (0.660 +/- 0.09 vs. 0.747 +/- 0.10 g/cm2) and total bone mineral density (BMD) (0.788 +/- 0.11 vs. 0.884 +/- 0.11 g/cm2) were lower (all P < or = 0.001) in FxMGUS compared with Nfx patients. Receiver operating characteristic curves identified lumbar BMD as the variable that best predicted vertebral fractures (area under the curve 0.817; 95% confidence interval, 0.713-0.921). This study provides an indication for the measurement of BMD in MGUS patients, as a means of predicting vertebral fractures, especially in those that are asymptomatic. Patients with prevalent fractures should undergo pharmacological treatment to prevent further fractures.

Advances in the management of myeloma bone disease

Multiple myeloma is the second most common adult haematological malignancy. One of the major clinical features is the development of a unique osteolytic bone disease, characterised by progressive and devastating bone destruction, bone pain, pathological fractures and hypercalcaemia. Bisphosphonates, inhibitors of osteoclastic bone resorption, are the standard therapy for myeloma-induced bone disease. However, as our understanding of the molecular mechanisms involved in the development of myeloma bone disease increases, new molecular targets have been identified for the treatment of this devastating bone disease.

First-line therapy with thalidomide, dexamethasone and zoledronic acid decreases bone resorption markers in patients with multiple myeloma

BACKGROUND

Bone involvement is frequently observed in multiple myeloma (MM) patients both at diagnosis and during the course of the disease. The evaluation of biochemical markers of bone turnover could allow a dynamic evaluation of the effects of a given therapy on bone metabolism.

METHODS

In the present study, markers of bone resorption [urinary free pyridinoline (PYD), deoxypyridinoline (DPYD), N-terminal telopeptide of collagen I (NTX) and C-terminal telopeptide (serum crosslaps)] and of bone formation [bone alkaline phosphatase (BAP) and osteocalcin] were evaluated at diagnosis and after induction therapy in 40 patients (23M, 17F, median age = 53.5 yr) enrolled in the 'Bologna 2002' clinical trial. By study design, all patients received 4 months of combined thalidomide (100 mg/d for 2 wk then 200 mg/d), dexamethasone (40 mg/d on days 1-4, 9-12, 17-20/28 on odd cycles and on days 1-4 on even cycles) and zoledronic acid (4 mg/28 d).

RESULTS

At diagnosis, although bone resorption markers were increased in more than 40% of the patients, only NTX (P = 0.029) and crosslaps (P = 0.000) were significantly related to the extent of skeletal lesions, as assessed by X-ray. After 4 months of therapy, a significant decrease in mean (+/-SE) urinary NTX (52.7 +/-6.9 nmol/mmol creatinine +/-6.9 vs. 14 +/- 1.42 nmol/mmol creatinine, P = 0.000) and serum crosslaps (6242.4 +/-945 pmol/L vs. 1414.9 +/- 173.8 pmol/L, P = 0.000) was observed in patients obtaining > or =partial response, at variance to what has been detected in patients showing <partial response.

CONCLUSIONS

Among all bone resorption markers, urinary NTX and serum crosslaps seem to be strictly related to the extent of bone involvement in MM. Combined thalidomide + dexamethasone and zoledronic acid seem to be highly effective in reducing bone resorption in sensitive patients, although the relative contribution of each drug cannot yet be determined.

Biochemical markers of bone metabolism in multiple myeloma

Osteolytic bone disease is a major clinical feature of multiple myeloma (MM). Mechanisms of bone destruction are related to increased osteoclastic activity, which is not accompanied by a comparable increase in bone formation, as osteoblasts are functionally exhausted. Thus the lesions rarely heal and bone scans are often negative in myeloma patients with extensive lytic lesions, offering very little in the follow-up of bone disease. Biochemical markers of bone resorption, such as N- and C-terminal cross-linking telopeptide of type I collagen (NTX, CTX/ICTP, respectively), tartrate resistant acid phosphatase isoform-5b, bone formation (bone-specific alkaline phosphatase [BAP]), and osteocalcin provide useful information on bone dynamics. Several studies have shown that NTX, CTX, and ICTP are elevated in myeloma patients, reflect the extent of bone disease, and correlate with survival. Furthermore, they are useful in monitoring bone destruction during antimyeloma or bisphosphonate treatment. Markers of bone formation have produced conflicting results in trials. However, BAP correlates with bone pain, lytic lesions, and fractures in quite a few studies of MM. Novel markers, such as bone sialoprotein, receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin, osteopontin, dickkopf-1, and soluble Frizzle-related protein-2 have been found of value in assessing bone lytic disease in MM, but their promising results must be confirmed in large trials. In conclusion, although no marker provides optimal analysis of MM or of MM treatments, combinations of markers have at times helped in assessing MM stages and lytic bone disease and in monitoring specific treatment modalities. The need for further research in this field is clear.

The role of markers of bone remodeling in multiple myeloma

Osteolytic bone disease is a frequent complication of multiple myeloma, resulting in skeletal complications that are a significant cause of morbidity and mortality. A characteristic feature of myeloma bone disease is that the lesions rarely heal and bone scans are often negative in myeloma patients who have extensive lytic lesions, offering very little in the follow-up of bone disease. X-rays are also of limited value in monitoring bone destruction during anti-myeloma or anti-resorptive treatment. Biochemical markers of bone turnover, such as N- and C-terminal cross-linking telopeptide of type I collagen (NTX, CTX/ICTP, respectively), and newer ones such as the tartrate resistant acid phosphatase isoform 5b, provide information on bone dynamics that in turn may reflect disease activity in bone. Several studies have shown bone markers to be elevated in myeloma patients and reflect the extent of bone disease, while in some of them bone resorption markers correlate with survival. These markers may also be helpful in identifying those patients likely to respond to bisphosphonate treatment, and monitoring the effectiveness of bisphosphonate therapy in the management of myeloma bone disease. This review attempts to summarize the existing data for the role of markers of bone remodeling in assessing the extent of bone destruction in myeloma and monitoring bone turnover during specific anti-myeloma treatment. We also discuss some novel markers that may be of particular interest in the near future.

Fracture risk in monoclonal gammopathy of undetermined significance

To assess fractures in monoclonal gammopathy of undetermined significance (MGUS), the precursor of multiple myeloma, we followed 488 Olmsted County, MN, residents with MGUS in a retrospective cohort study. There was a 2.7-fold increase in the risk of axial fractures but no increase in limb fractures. The pathophysiologic basis for the increased axial fractures should be determined.

INTRODUCTION

Multiple myeloma is often preceded by monoclonal gammopathy of undetermined significance (MGUS). Fractures are common in myeloma as a result of lytic bone lesions, generalized bone loss, and elevated bone turnover from excessive cytokine production. Whether fractures are also increased in MGUS is unknown.

MATERIALS AND METHODS

In a population-based retrospective cohort study, 488 Olmsted County, MN, residents with MGUS first diagnosed in 1960-1994 (52% men; mean age, 71.4 +/- 12.8 years) were followed for 3901 person-years; follow-up was censored at progression to myeloma. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models.

RESULTS AND CONCLUSIONS

Altogether, 200 patients experienced 385 fractures. Compared with expected rates in the community, statistically significant increases were seen for fractures at most axial sites, for example, vertebrae (SIR, 6.3; 95% CI, 5.2-7.5). There was a slight increase in hip (SIR, 1.6; 95% CI, 1.2-2.2) but not distal forearm fractures (SIR, 0.8; 95% CI, 0.4-1.5). The relative risk (SIR) of any axial fracture was 2.7 (95% CI, 2.3-3.1) compared with only 1.1 (95% CI, 0.9-1.4) for all limb fractures combined. In a multivariate analysis, the independent predictors of any subsequent fracture were age (hazard ratio [HR] per 10-year increase, 1.4; 95% CI, 1.2-1.6) and corticosteroid use (HR, 1.8; 95% CI, 1.2-2.6); greater weight at diagnosis (HR per 10 kg, 0.8; 95% CI, 0.8-0.9), and IgG monoclonal protein (HR, 0.7; 95% CI, 0.5-0.97) were protective. Baseline monoclonal protein level, a determinant of myeloma progression, did not predict fracture risk. Thus, the risk of axial, but not peripheral, fractures is increased among MGUS patients even before progression to myeloma. The pathophysiologic basis for this should be determined because elevated bone turnover, for example, might be treatable.

Pamidronate is superior to ibandronate in decreasing bone resorption, interleukin-6 and beta 2-microglobulin in multiple myeloma

OBJECTIVES

Bisphosphonates have been found to reduce skeletal events in patients with multiple myeloma (MM). This is the first randomised trial to compare the efficacy of pamidronate and ibandronate, a third-generation aminobisphosphonate, in bone turnover and disease activity in MM patients.

METHODS

Patients with MM, stage II or III, were randomly assigned to receive either pamidronate 90 mg (group I: 23 patients) or ibandronate 4 mg (group II: 21 patients) as a monthly intravenous infusion in addition to conventional chemotherapy. Skeletal events, such as pathologic fractures, hypercalcaemia, and bone radiotherapy were analysed. Bone resorption markers [N-terminal cross-linking telopeptide of type-I collagen (NTX) and tartrate-resistant acid phosphatase type 5b (TRACP-5b)], bone formation markers (bone alkaline phosphatase and osteocalcin), markers of disease activity (paraprotein, CRP, beta 2-microglobulin), and interleukin-6 (IL-6) were also studied.

RESULTS

In both groups, the combination of chemotherapy with either pamidronate or ibandronate produced a reduction in bone resorption and tumour burden as measured by NTX, IL-6, paraprotein, CRP, and beta 2-microglobulin from the second month of treatment, having no effect on bone formation. TRACP-5b also had a significant reduction in the pamidronate group from the second month of treatment and in the ibandronate group from the sixth month. However, there was a greater reduction of NTX, IL-6, and beta 2-microglobulin in group I than in group II, starting at the second month of treatment (P = 0.002, 0.001, and 0.004, respectively) and of TRACP-5b, starting at the fourth month (P = 0.014), that being continued throughout the 10-month follow-up of this study. There was no difference in skeletal events during this period. A significant correlation was observed between changes of NTX and changes of TRACP-5b, IL-6, and beta 2-microglobulin from the second month for patients of both groups.

CONCLUSIONS

These results suggest that a monthly dose of 90 mg of pamidronate is more effective than 4 mg of ibandronate in reducing osteoclast activity, bone resorption, IL-6, and possibly tumour burden in MM. TRACP-5b has also proved to be a useful new marker for monitoring bisphosphonates treatment in MM.

Comparison of five biochemical markers of bone resorption in multiple myeloma: elevated pre-treatment levels of S-ICTP and U-Ntx are predictive for early progression of the bone disease during standard chemotherapy

Increased osteoclastic bone resorption is the major causal factor of bone disease in multiple myeloma. Recently, non-invasive methods have been developed for the estimation of bone resorptive activity. To evaluate the biological sensitivity and clinical usefulness of five biochemical assays for measuring the C-terminal telopeptide of collagen I (ICTP) in serum (beta-Crosslaps ELISA and ICTP radioimmunoassay) and urinary creatinine-adjusted excretions of pyridinoline (PYR), deoxypyridinoline (DPD) and N-terminal telopeptide of collagen I (Ntx), we performed a study of 34 consecutive newly diagnosed myeloma patients. Serum and morning-fasting, second-void urine samples were taken before the start of treatment. In total, 40 age- and sex-adjusted healthy individuals served as controls. Results were expressed as Z-scores. All test variables were highly significantly elevated in the patients (P < 0.001). Serum (S)-ICTP was elevated (Z-score > 2) in most patients (85%) and showed significantly higher Z-score values than the other markers. S-ICTP remained more sensitive than the urinary assays when patients with impaired renal function were excluded from analysis. S-ICTP and the urinary metabolites correlated significantly with skeletal morbidity. S-beta-Crosslaps correlated with the bone morbidity only when patients with renal insufficiency were excluded from the analysis. High levels of S-ICTP and urinary (U)-Ntx correlated with an increased risk for early progression of bone lesions during standard melphalan-prednisolone treatment. U-Ntx and S-ICTP are sensitive tools for estimating the increased bone resorption in multiple myeloma and are clinically useful for identifying patients with increased risk of early progression of bone disease.

Evaluation of bone disease in multiple myeloma: a correlation between biochemical markers of bone metabolism and other clinical parameters in untreated multiple myeloma patients

INTRODUCTION

Multiple myeloma (MM) is characterised by an uncoupled bone formation/resorption process resulting in osteolysis. Osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) are markers of osteoblastic activity, whereas pyridinoline products and the cross-linked aminoterminal of type I collagen (NTx) reflect bone destruction. In this study, these markers were studied in relation to bone disease severity and other clinical parameters of MM activity.

METHODS

Serum calcium, creatinine, CRP, beta 2 microglobulin (b(2)M), M-component, OC, BAP and free urine pyridoline (Pyd) and deoxypyridinoline (Dpd), free urine Dpd and NTx were determined in 38 newly diagnosed MM patients. X-ray examination defined the degree of bone involvement. Patients were classified according to the Durie-Salmon staging system.

RESULTS

NTx, free urine Pyd + Dpd, and free urine Dpd increased with increasing degree of bone involvement. NTx was significantly higher in stages II and III compared to stage I (mean values: 100.7, 163.5 and 208.3 nmol BCE/mM creat, respectively, p < 0.002). Free urine Pyd + Dpd correlated positively with b(2)M and CRP. OC was increased in stages I and II compared to III (p < 0.005) and was inversely correlated with NTx, free urine Pyd + Dpd, and free urine Dpd alone.

CONCLUSIONS

The measurement of bone turnover markers in MM provides significant information regarding disease progression and should be included in the evaluation of MM patients.