Acute effects of high-dose chemotherapy followed by bone marrow transplantation on serum markers of bone metabolism

Risk Factors for Hematopoietic Stem Cell Transplantation-Associated Bone Loss

Hematopoietic stem cell transplantation (HSCT), including bone marrow transplantation, is the treatment of choice for many hematologic diseases, including hematologic malignancies and different types of anemia. The use of HSCT is increasing annually, mainly because advanced research that has been conducted in this area has exponentially expanded the indications for HSCT and significantly improved transplantation techniques and supportive care practices. Collectively, these improvements have led to an increase in the overall survival of HSCT patients. However, as post-HSCT survival is increasing, awareness of the potential late complications of HSCT is also growing. Unpredictable bone loss is one of the major post-HSCT complications that can cause significant morbidity and impair the quality of life of survivors. Although the exact mechanism of post-HSCT bone loss is not yet known, previous studies have suggested that numerous factors, including destructive preparative regimens (eg, high-dose chemotherapy, total body irradiation), treatment-related complications (eg, graft-versus-host disease), endocrine abnormalities (eg, diabetes mellitus, thyroid dysfunction, adrenal insufficiency), lack of physical activity, and the underlying disease itself are responsible for HSCT-associated bone loss. Sufficient data have been collected to suggest that post-HSCT bone loss can be prevented and treated using the same preventive and treatment modalities as used for the general population. Various guidelines have been formulated to help keep a check on HSCT recipients' deteriorating bone health.

High-dose therapy improves the bone remodelling compartment canopy coverage and bone formation in multiple myeloma

Bone loss in multiple myeloma (MM) is caused by an uncoupling of bone formation to resorption trigged by malignant plasma cells. Increasing evidence indicates that the bone remodelling compartment (BRC) canopy, which normally covers the remodelling sites, is important for coupled bone remodelling. Loss of this canopy has been associated with bone loss. This study addresses whether the bone remodelling in MM is improved by high-dose therapy. Bone marrow biopsies obtained from 20 MM patients, before and after first-line treatment with high-dose melphalan followed by autologous stem cell transplantation, and from 20 control patients with monoclonal gammopathy of undetermined significance were histomorphometrically investigated. This investigation confirmed that MM patients exhibited uncoupled bone formation to resorption and reduced canopy coverage. More importantly, this study revealed that a good response to anti-myeloma treatment increased the extent of formative bone surfaces with canopy, and reduced the extent of eroded surfaces without canopy, reverting the uncoupled bone remodelling, while improving canopy coverage. The association between improved coupling and the canopy coverage supports the notion that canopies are critical for the coupling of bone formation to resorption. Furthermore, this study supports the observation that systemic bone disease in MM can be reversed in MM patients responding to anti-myeloma treatment.

The influence of therapeutic radiation on the patterns of bone remodeling in ovary-intact and ovariectomized mice

Our purpose was to characterize changes in bone remodeling associated with localized radiation that models therapeutic cancer treatment in ovary-intact (I) and ovariectomized (OVX) mice and to evaluate the influence of radiation on the pattern of bone mineral remodeling. Young adult, female BALB/c mice, I and OVX, were used (n = 71). All mice were intravenously injected with 15 μCi (45)Ca. Thirty days post-(45)Ca administration, the hind limbs of 17 mice were exposed to a single dose of 16 Gy radiation (R). The time course of (45)Ca excretion, serum CTx and osteocalcin markers, and cancellous bone volume fraction (BV/TV) and cortical thickness (Ct.Th) of the distal femur were assayed. Cellular activity and dynamic histomorphometry were performed. Irradiation resulted in rapid increases in fecal (45)Ca excretion compared to control groups, indicating increased bone remodeling. CTx increased rapidly after irradiation, followed by an increase in osteocalcin concentration. BV/TV decreased in the I mice following irradiation. Ct.Th increased in the OVX groups following irradiation. I+R mice exhibited diminished osteoblast surface, osteoclast number, and mineral apposition. Our murine model showed the systemic effects (via (45)Ca excretion) and local effects (via bone microarchitecture and surface activity) of clinically relevant, therapeutic radiation exposure. The I and OVX murine models have similar (45)Ca excretion but different bone microarchitectural responses. The (45)Ca assay effectively indicates the onset and rate of systemic bone mineral remodeling, providing real-time assessment of changes in bone histomorphometric parameters. Monitoring bone health via a bone mineral marker may help to identify the appropriate time for clinical intervention to preserve skeletal integrity.

NCI, NHLBI/PBMTC first international conference on late effects after pediatric hematopoietic cell transplantation: endocrine challenges-thyroid dysfunction, growth impairment, bone health, & reproductive risks

The endocrine system is highly susceptible to damage by high-dose chemotherapy and/or irradiation before hematopoietic cell transplantation (HCT) during childhood. The specific endocrine organs most affected by HCT include the thyroid gland, the pituitary, and the gonads. In addition, hormones that support development and stability of the skeletal system are also affected. Insufficiency of thyroid hormone is 1 of the most common late sequelae of HCT, and occurs more often in young children. Deficiency in the pituitary's production of growth hormone is a problem of unique concern to the pediatric population. The reproductive risks of HCT depend on the patient's gender and pubertal status at the time of HCT. Pubertal or gonadal failure frequently occurs, especially in females. Infertility risks for both genders remain high, whereas methods of fertility preservation are limited in all but postpubertal males. Bone health post-HCT can be compromised by low bone mineral density as well as avascular necrosis, but the data on both problems in the pediatric HCT population are limited. In this paper, the current state of knowledge, gaps in that knowledge, and recommendations for future research are addressed in detail for each of these systems.

Loss of bone mineral density and secondary hyperparathyroidism are complications of autologous stem cell transplantation

Patients who underwent autologous stem cell transplantation (ASCT) are prone to decreased bone mineral density (BMD). We measured BMD in 180 patients who underwent ASCT for hematologic malignancies. Patients were evaluated with a median of 6.2 years after ASCT. Twenty patients who received only chemotherapy were evaluated as controls. The loss of bone mass was greater during the first year after ASCT, since majority of patients recover BMD and normalize bone turnover markers during the following years. After ASCT, over half of the patients show osteopenia or osteoporosis independent of the sex. According to the results of other groups, our results emphasize the potential usefulness of antiresorptive agents to prevent or treat post-ASCT osteopenia or osteoporosis, and the importance of the measurement of BMD as an integral component to the follow-up of ASCT.

Bortezomib increases osteoblast activity in myeloma patients irrespective of response to treatment

OBJECTIVES

Myeloma bone disease is a result of excessive osteoclast activation and impaired osteoblast function. Recent in vitro studies suggested that proteasome inhibitors might increase osteoblast function.

METHODS

We analyzed serum markers of osteoblast activity in 25 patients with multiple myeloma receiving bortezomib alone or in combination with dexamethasone. As control, serum samples from 58 consecutive myeloma patients receiving a therapy different than bortezomib (i.e. adriamycin/dexamethasone, melphalan/prednisone or thalidomide) were evaluated. The serum concentrations of bone-specific alkaline phosphatase (BAP) and osteocalcin were quantified before initiation of treatment and after 3 months.

RESULTS

In patients treated with bortezomib, mean serum levels of osteocalcin significantly increased from 6.3 to 10.8 microg/L (P = 0.024), while mean BAP levels increased from 19.7 to 30.2 U/L (P < 0.0005). Of interest, the increase in BAP was significant both in responders and non-responders. In contrast, the control group did not show a statistically significant change in BAP (24.8 U/L vs. 23.3 U/L) and osteocalcin (6.8 microg/L vs. 6.5 microg/L) before and after the treatment.

CONCLUSION

These data show that treatment with bortezomib leads to enhanced markers of osteoblast activity in patients with myeloma. The comparison with the control group suggests that the effect on osteoblasts is unique to the proteasome inhibitor.

Bone markers in multiple myeloma

Bone disease, a hallmark of multiple myeloma occurs in the majority of the patients, is associated with bone pain, fractures, hypercalcemia and has major impacts on quality of life. Myeloma is characterized by a unique form of bone disease with osteolytic bone destruction that is not followed by reactive bone formation, resulting in extensive lytic lesions. This review will focus on the pathophysiology of osteoclast activation and osteoblast inhibition in multiple myeloma and on biochemical markers of bone turnover. Since osteolytic lesions do not rapidly heal in myeloma, X-rays cannot reflect the activity of bone disease during antimyeloma treatment. Activity in bone turnover does not parallel changes in monoclonal protein levels. Thus, there is a need for biochemical markers reflecting disease activity in bone. The utility, prognostic implications and limitations of classical and novel markers of bone remodeling (e.g. ICTP, NTx, TRACP-5b, osteoprotegerin, sRANKL) will be discussed in this overview.

Osteopontin is a hematopoietic stem cell niche component that negatively regulates stem cell pool size

Stem cells reside in a specialized niche that regulates their abundance and fate. Components of the niche have generally been defined in terms of cells and signaling pathways. We define a role for a matrix glycoprotein, osteopontin (OPN), as a constraining factor on hematopoietic stem cells within the bone marrow microenvironment. Osteoblasts that participate in the niche produce varying amounts of OPN in response to stimulation. Using studies that combine OPN-deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell number and function in a stem cell–nonautonomous manner. The OPN-null microenvironment was sufficient to increase the number of stem cells associated with increased stromal Jagged1 and Angiopoietin-1 expression and reduced primitive hematopoietic cell apoptosis. The activation of the stem cell microenvironment with parathyroid hormone induced a superphysiologic increase in stem cells in the absence of OPN. Therefore, OPN is a negative regulatory element of the stem cell niche that limits the size of the stem cell pool and may provide a mechanism for restricting excess stem cell expansion under conditions of niche stimulation.

Bone metabolism in patients more than five years after bone marrow transplantation

We investigated the bone metabolism of 22 patients (median age 38 years) over 6 years after allogeneic bone marrow transplantation (BMT). Biplanar roentgenograms of the thoracic and lumbar spine were used to diagnose vertebral deformities caused by fractures. The actual bone mineral density (BMD) of the lumbar spine and the femoral neck were measured. Laboratory tests included calcium, phosphate, parathyroid hormone, a marker of bone resorption (beta-crosslaps, CTX), markers of bone formation (osteocalcin, bone-specific alkaline phosphatase), osteoprotegerin (OPG)--antagonist of the osteoclast differentiation factor RANKL, and sex hormone status. One patient had a vertebral fracture. Seven patients (28%) had osteopenia in the lumbar spine while 12 patients (48%) had osteopenia in the femoral neck. Bone resorption was increased in nine patients (43%) and bone formation was increased in four patients (20%). BMT recipients had significantly increased serum levels of OPG (P=0.029). Three women (75%) and four men (25%) were hypogonadal. The data showed that BMD is reduced and bone metabolism is still disturbed more than 6 years after BMT. The RANKL/osteoprotegerin system appears to play an important role in the pathophysiology of late post transplantation osteoporosis.

Autologous stem cell transplantation normalizes abnormal bone remodeling and sRANKL/osteoprotegerin ratio in patients with multiple myeloma

The osteoprotegerin (OPG)/receptor activator of NF-kappa B ligand (RANKL) system has a major role in the pathogenesis of bone disease in myeloma (MM). The effect of autologous stem cell transplantation (ASCT) on bone turnover in MM was evaluated in 51 patients (35M/16F). Markers of bone resorption (NTX, TRACP-5b), bone formation (bone-alkaline phosphatase (bALP), osteocalcin), OPG and sRANKL were measured pre- and every month post-ASCT. The median follow-up period was 12 months. Four patients were transplanted in CR, 44 were transplanted in PR and three patients had progressive/resistant disease. All patients received bisphosphonates both pre- and post-ASCT. At baseline the majority of patients had increased NTX, TRACP-5b levels, and sRANKL/OPG ratio, while markers of bone formation were strongly suppressed. ASCT produced a significant reduction of sRANKL/OPG ratio, with a concomitant decrease of NTX, and TRACP-5b levels, starting the second month post-ASCT. Bone formation markers, osteocalcin and bALP, started to increase after the 9th and 11th month post-ASCT, respectively, while the increase of OPG preceded this. These results provide biochemical evidence that ASCT normalizes the abnormal bone resorption in MM patients possibly through the decrease of RANKL/OPG ratio, while bone formation requires a longer period to return to normal.

Impact of circulating bone-resorbing cytokines on the subsequent bone loss following bone marrow transplantation

Cytokines including IL-6 and TNF-alpha play an important role in the pathogenesis of postmenopausal osteoporosis. However, the relationship between changes in the cytokine levels and subsequent bone loss in patients undergoing a bone marrow transplantation (BMT) is unclear. A total of 46 patients undergoing an allogeneic BMT were prospectively investigated. The bone turnover markers and the serum cytokines were measured before BMT and serially after BMT. Bone mineral density (BMD) was measured before and 1 year after BMT. At 1 year after BMT, the lumbar spine BMD had decreased by 4.8%, and the total proximal femoral BMD had decreased by 12.3%. The serum IL-6 and TNF-alpha levels increased until 2 and 3 weeks after BMT, respectively. The lumbar BMD was significantly decreased as the serum IL-6 and TNF-alpha levels increased by post-BMT 3 weeks. The lumbar BMD decreased significantly as the cumulative prednisolone and cyclosporine dose increased. Patients with GVHD > or =grade II had higher lumbar bone loss than patients with GVHD <grade I. In conclusion, immunosuppressants, GVHD occurrence and increase in bone-resorbing cytokines in the early post-BMT period were associated with later bone loss after BMT. Further studies are needed to elucidate the precise mechanism.

Changes in the serum growth factors and osteoprotegerin after bone marrow transplantation: impact on bone and mineral metabolism

The loss of bone mass often occurs after bone marrow transplantation (BMT), particularly during the early posttransplant period. There are few reports on the role of growth factors and osteoprotegerin (OPG) in the post-BMT bone loss. This study prospectively investigated 110 patients undergoing BMT and analyzed 36 patients who had dual-energy x-ray absorptiometry performed before BMT and 1 yr after BMT. The biochemical markers of bone formation and resorption were measured at the short-term intervals during the year-long follow-up. The serum IGF-I, IGF binding protein (IGFBP)-3, fibroblast growth factor-2, macrophage-colony stimulating factor (M-CSF), and OPG levels were measured before and 1 wk, 3 wk, and 3 months after BMT. The mean bone loss in the lumbar spine and the total proximal femur, which was calculated as the percent change from the baseline to the level at 1 yr, was 5.2% (P < 0.05) and 11.6% (P < 0.01), respectively. During the immediate post-BMT period, bone formation decreased, whereas bone resorption increased, which was indicated by the biochemical markers of bone turnover. The serum IGF-I levels also decreased progressively until 3 wk and then increased to the basal values at 3 months. The serum IGFBP-3 levels decreased progressively until 3 months. The serum fibroblast growth factor-2 levels decreased to the nadir at 1 wk and gradually recovered to the basal values at 3 months. The serum M-CSF levels increased immediately after BMT, which declined to its baseline level by 3 months. The serum OPG levels increased progressively, reached a peak at 3 weeks, and declined thereafter. There were significant correlations between the IGF-I and osteocalcin levels before BMT and at 3 wk after BMT (r = 0.45, P < 0.01; r = 0.54, P < 0.01). During the observation period, the serum IGFBP-3 and M-CSF levels showed positive correlations with the osteocalcin and serum collagen I carboxyl-terminal telopeptide levels, respectively. Although statistically not significant, the OPG levels tended to be positively associated with the serum collagen I carboxyl-terminal telopeptide levels. Significant correlations were observed between the percent changes from the baseline to 1 yr in the bone mineral density at the proximal femur and the serum IGF-I levels at 3 wk and 3 months after BMT (r = 0.52, P < 0.01; r = 0.41, P < 0.05).

Osteoblast and osteoclast activity in a malignant infantile osteopetrosis patient following bone marrow transplantation

The authors treated a 6-month-old boy with malignant infantile osteopetrosis using bone marrow transplantation. The patient's clinical response was compared with his biochemical response for bone metabolic markers such as tartrate-resistant acid phosphatase 5b (TRAcP 5b) and bone-specific alkaline phosphatase (BAP). Treatment was successful, resulting in a decrease in the serum TRAcP 5b level. These bone-specific markers may be useful for the early assessment of malignant infantile osteopetrosis patients with stem cell transplantation.

Significant and persistent loss of bone mineral density in the femoral neck after haematopoietic stem cell transplantation: long-term follow-up of a prospective study

Reduced bone mineral density (BMD) has been reported following allogeneic stem cell transplantation (alloSCT) but the effects of autologous SCT (autoSCT) are less well characterized. We performed a prospective study of BMD changes and its determinants in 44 SCT recipients (38 auto and six allo; 30 peripheral blood SCT and 14 bone marrow transplantation). Serial measurements of BMD at the lumbar spine and femoral neck were performed at baseline and at 3, 6, 12 and 24 months, and spinal radiographs were performed at baseline and 12 months. Mean baseline BMD values at the femoral neck and spine were within normal limits. At 3 months, there was a significant decline of BMD at the femoral neck (P = 0.011) and a non-significant trend towards reduction at the spine. BMD loss persisted for up to 2 years at the femoral neck (P = 0.005), but values returned to baseline at the spine. Reflecting the rapid initial decline in BMD, bone-specific alkaline phosphatase (a serum marker of bone formation) showed a significant initial decline at 1 month but had recovered to pretransplant levels by 3 months. No new fractures were detected at 1 year post transplant. Sex, diagnosis, use of total body irradiation, stem cell source and type of graft (auto versus allo) did not significantly predict BMD change over the first 12 months. In conclusion, significant and persistent bone loss at the femoral neck was demonstrated in this group of patients following stem cell transplantation. The implications of these findings for future fracture risk require further study.

Decreased bone mineral density is common after autologous blood or marrow transplantation

Survivors of autologous blood or marrow transplantation (ABMT) are predisposed to decreased bone mineral density (BMD), but data are lacking on the incidence and risk factors for this condition. Therefore, we measured BMD in 64 of 68 consecutive ABMT survivors (35 men and 29 women) attending the University of Toronto ABMT long-term follow-up clinic. Patients were evaluated a median of 4.2 years (range: 4.9 months-11.4 years) after ABMT. Median age at evaluation was 49.6 years (range: 23.5-68.2 years). At the L1-L4 vertebrae, 17 (26%) patients (eight men and nine women) had osteopenia and one male (2%) had osteoporosis. Mean BMD at L1-L4 did not differ from healthy young adults or age and sex matched controls. At the femoral neck, 30 patients (46%) (18 men and 12 women) had osteopenia and five (8%) (two men and three women) had osteoporosis. Mean BMD at the femoral neck was significantly lower than in healthy young adults and age- and sex-matched controls. By regression analysis, patients with decreased BMD were older than those with normal BMD (P = 0.02). Gender, body mass index, time from BMT to evaluation and presence of hypogonadism were not associated with decreased BMD. Treatment of decreased bone density was instituted and follow-up data were obtained 1 year after treatment in 22 of 39 patients with reduced BMD. Nineteen (86%) patients had stabilization or improvement of their bone density at follow-up. We conclude that, after ABMT, over half of the patients have evidence of osteopenia or osteoporosis. Men and women were equally affected. In our study, only older age at evaluation was predictive for loss of BMD. We recommend the measurement of BMD as an integral component to the follow-up of ABMT patients.

Biochemical markers of bone turnover following high-dose chemotherapy and autografting in multiple myeloma

The effect of high-dose chemotherapy and autografting on bone turnover in myeloma is not known. A study of 32 myeloma patients undergoing blood or marrow transplant (BMT), conditioned with high-dose melphalan, was done. Bone resorption was assessed by urinary free pyridinoline (fPyr) and deoxypyridinoline (fDPyr), expressed as a ratio of the urinary creatinine concentration. Bone formation was assessed by serum concentration of procollagen 1 extension peptide (P1CP) and bone-specific alkaline phosphatase (BSAP). Eighteen cases had normal fPyr and fDPyr at transplant, and in all but one of these cases the level remained normal throughout subsequent follow-up. In contrast, in 14 cases urinary fPyr and fDPyr levels were increased at transplant. In these cases, both fPyr and fDPyr fell to normal levels over the next few months (P = .0009 and .0019, respectively). fPyr and fDPyr levels at transplant and their trends post-BMT were unrelated to the use of pre-BMT or post-BMT bisphosphonate or post-BMT interferon. Nine cases had elevated P1CP or BSAP at transplant, which rapidly normalized. In most patients there was an increase in P1CP and/or BSAP several months post-transplant. In conclusion, increased osteoclast activity may be present even in apparent plateau phase of myeloma. High-dose chemotherapy with autografting may normalize abnormal bone resorption, although the effect may take several weeks to emerge and may be paralleled by increased osteoblast activity. The findings provide biochemical evidence that autografting may help normalize the abnormal bone turnover characteristic of myeloma.

Biochemical markers of bone turnover following high-dose chemotherapy and autografting in multiple myeloma

The effect of high-dose chemotherapy and autografting on bone turnover in myeloma is not known. A study of 32 myeloma patients undergoing blood or marrow transplant (BMT), conditioned with high-dose melphalan, was done. Bone resorption was assessed by urinary free pyridinoline (fPyr) and deoxypyridinoline (fDPyr), expressed as a ratio of the urinary creatinine concentration. Bone formation was assessed by serum concentration of procollagen 1 extension peptide (P1CP) and bone-specific alkaline phosphatase (BSAP). Eighteen cases had normal fPyr and fDPyr at transplant, and in all but one of these cases the level remained normal throughout subsequent follow-up. In contrast, in 14 cases urinary fPyr and fDPyr levels were increased at transplant. In these cases, both fPyr and fDPyr fell to normal levels over the next few months (P = .0009 and .0019, respectively). fPyr and fDPyr levels at transplant and their trends post-BMT were unrelated to the use of pre-BMT or post-BMT bisphosphonate or post-BMT interferon. Nine cases had elevated P1CP or BSAP at transplant, which rapidly normalized. In most patients there was an increase in P1CP and/or BSAP several months post-transplant. In conclusion, increased osteoclast activity may be present even in apparent plateau phase of myeloma. High-dose chemotherapy with autografting may normalize abnormal bone resorption, although the effect may take several weeks to emerge and may be paralleled by increased osteoblast activity. The findings provide biochemical evidence that autografting may help normalize the abnormal bone turnover characteristic of myeloma.

The short-term changes of bone mineral metabolism following bone marrow transplantation

Organ transplantation is now the treatment of choice for many patients with life-threatening chronic diseases. A new set of side effects unique to these groups of patients has become recognized, and bone disease is one of these complications. However, little is known about the effects of myeloablative treatment followed by bone marrow transplantation (BMT) on bone mineral metabolism. We have prospectively investigated 31 patients undergoing BMT for hematologic diseases. Serum concentrations of calcium, phosphorus, creatinine, gonadotropins, sex hormones, and the biochemical markers of bone turnover were measured. The samples were collected before BMT and 1, 2, 3, 4, and 12 weeks, 6 months, and 1 year after BMT. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry before BMT and 1 year after BMT. The serum carboxy-terminal cross-linked telopeptide of type I collagen increased progressively until 4 weeks after BMT. Thereafter, it began to decrease and reached basal values after 1 year. Serum osteocalcin decreased progressively until 3 weeks after BMT. After that, it increased and reached basal values after 3 months. No distinct differences were observed in the serum biochemical turnover markers between males and females, or between patients who received total body irradiation and those who did not. One year after BMT, lumbar spine BMD had decreased by 2.2%, and total proximal femoral BMD had decreased by 6.2%. Eighty-six percent of the women (12/14) went into a menopausal state immediately after BMT. This was caused by high gonadotropin levels and low estradiol levels. In contrast, gonadotropin levels and testosterone levels did not change significantly in the male patients after BMT. In conclusion, the rapid impairment of bone formation and the increase in bone resorption, as shown by the biochemical markers in this study, might play a role in post-BMT bone loss.

Mechanisms of bone loss following allogeneic and autologous hemopoietic stem cell transplantation

A significant proportion of patients will be long-term survivors of bone marrow transplantation (BMT) and little is known about their risk of late bony complications. We therefore evaluated bone mineral density (BMD) prior to BMT, post-transplantation changes in BMD, and mechanisms of bone loss in long-term survivors. We performed two analyses. The first was a cross-sectional study of 83 consecutive BMT patients (38 F, 45 M), examining the relationship between BMD and bone turnover, measured immediately prior to transplantation, and a number of disease and patient variables. The second was a prospective study of 39 patients (19F, 20 M) followed for a median of 30 months (range 5-64 months) following either allogeneic (allo, n = 29) or autologous (auto, n = 10) BMT to determine if bone loss was related to treatment of graft versus host disease (GVHD) with glucocorticoids and cyclosporine A, high bone turnover rates, or hypogonadism. Auto BMT recipients acted as a control group for effects of GVHD therapy on BMD. Prior to BMT, spinal and femoral neck (FN) BMDs were 8.6% and 14% lower in female auto BMT recipients than in female allo BMT recipients, respectively (p = 0.12 and p = 0. 003). Urinary bone resorption markers were higher than in normal gender- and age-matched control subjects. Patients treated previously with glucocorticoids also had 8% lower FN BMD. Glucocorticoid-pretreated women with amenorrhoea had lower lumbar spine (LS) and FN BMDs than eumenorrheic women and women receiving HRT. Post-allo BMT, patients lost 11.7% of FN BMD compared with a nonsignificant decrease of 1.1% post-auto BMT (p < 0.001). Spinal BMD and total body bone mineral content (TBBMC) decreased by 3.9% and 3.5%, respectively, post-allo, compared with an increase (1.5%, p = 0.03) or nonsignificant decrease (-3.7%, p = NS), respectively, post-auto BMT. Post-allo BMT bone loss correlated best with the cumulative prednisolone dose at the LS and FN, and with average daily prednisolone dose for TBBMC. At the spine, the rate of bone loss was 4%/10 g of prednisolone, while the rate of bone loss at the FN was greater (9%/10 g of prednisolone). Bone loss was also negatively related to the duration of cyclosporine therapy for GVHD and baseline deoxypyridinoline concentrations. Avascular necrosis of the femoral head occurred in four, and vertebral and rib fractures occurred in one of the allo BMT patients, but in no auto BMT patients. In conclusion, BMT recipients are at risk of osteoporosis secondary to bone loss associated with their underlying illness and/or chemotherapy, particularly in female autograft recipients, and in allograft recipients secondary to GVHD and its treatment.

Osteoporosis after organ transplantation

Within the past 2 decades, organ transplantation has become established as effective therapy for endstage renal, hepatic, cardiac, and pulmonary disease. Regimens to prevent rejection after transplantation commonly include high-dose glucocorticoids and calcineurin-calmodulin phosphatase inhibitors (the cyclosporines and tacrolimus), which are detrimental to bone and mineral homeostasis, and are associated with rapid bone loss that is often superimposed upon an already compromised skeleton. The incidence of fracture ranges from 8% to 65% during the first year after transplantation. In general, fracture rates are lowest in renal transplant recipients and highest in patients who receive a liver transplant for primary biliary cirrhosis. Rates of bone loss and fracture are greatest during the first 6 to 12 months after transplantation. Postmenopausal women and hypogonadal men appear to be at increased risk. Although no pretransplant densitometric or biochemical parameter has yet been identified that adequately predicts fracture risk in the individual patient, low pretransplant bone mineral density does tend to increase the risk of fracture, particularly in women. However, patients may sustain fractures despite normal pretransplant bone mineral density. Although the pathogenesis of the rapid bone loss is multifactorial, prospective biochemical data suggest that uncoupling of bone formation from resorption may be in part responsible, at least during the first 3 to 6 months. Prevention of transplantation osteoporosis should begin well before transplantation. Patients awaiting transplantation should be evaluated with spine radiographs, bone densitometry, thyroid function tests, serum calcium, vitamin D, parathyroid hormone, and testosterone (in men). Therapy for osteoporosis, low bone mass, and potentially reversible biochemical causes of bone loss should be instituted during the waiting period before transplantation. In patients with normal pretransplant bone density, therapy to prevent early posttransplant bone loss should be instituted immediately following transplantation. Most pharmacologic agents available for therapy of osteoporosis have not been subject to prospective controlled studies in organ transplant recipients. However, antiresorptive drugs, such as biphosphonates, appear to hold therapeutic promise.

Relationship between bone metabolism and plasma cytokine levels in patients at risk of post-transplantation bone disease after bone marrow transplantation

Bone marrow transplant recipients may carry an increased risk of bone diseases, involving numerous factors that affect bone mineral metabolism. Interleukin-6 is a potent stimulator of bone resorption in vivo. The soluble fraction of interleukin-6 receptor is reported to trigger osteoclast formation by interleukin-6 in vitro. In a cross-sectional study we measured serum bone alkaline phosphatase concentrations and the urinary excretion of pyridinium cross-links in 21 patients after bone marrow transplantation, and investigated the relationship between these values and those for the plasma levels of interleukin-6 and soluble interleukin-6 receptor. Following bone marrow transplantation female--but not male--patients showed higher serum bone alkaline phosphatase values than age- and sex-adjusted controls (p < 0.05). Both female and male patients were characterized by increased urinary excretion values of pyridinium cross-links (p < 0.05). In contrast to a marked increase of interleukin-6 plasma levels (p < 0.001) no significant difference in the soluble interleukin-6 receptor levels was found between patients and apparently healthy persons (p = 0.838). Multiple regression analysis (taking into account different variables of the immunosuppressive regimen applied) revealed the plasma concentration of interleukin-6 as an independent predictor of the urinary excretion of pyridinium cross-links (p < 0.05). In conclusion, in patients following bone marrow transplantation, these findings indicate (a) an increase of bone formation in female--but not in male--patients possibly reflecting primary ovarian failure and (b) an enhancement of bone resorption possibly mediated by circulating interleukin-6.

Monitoring of bone metabolism after bone marrow transplantation by measuring two different markers of bone turnover

Bone marrow transplant recipients may be at increased risk of osteoporosis. In a cross-sectional study we therefore measured two biochemical markers of bone turnover, bone alkaline phosphatase and the C-terminal propeptide of type I procollagen, in 22 serum samples from 9 patients before allogeneic bone marrow transplantation and 85 serum samples from 14 patients after allogeneic bone marrow transplantation. Following allogeneic bone marrow transplantation, female (but not male) patients showed elevated serum bone alkaline phosphatase values (p < 0.05). After bone marrow transplantation both female and male patients were characterized by elevated serum concentrations of the C-terminal propeptide (p < 0.01). Both the duration of cyclosporin A therapy (p < 0.05) and the time since transplantation (p < 0.01) were independent predictors of serum bone alkaline phosphatase values, whereas the duration of cyclosporin A therapy was the only independent predictor of C-terminal propeptide serum concentrations (p < 0.01). There was a correlation between bone alkaline phosphatase serum concentrations and C-terminal propeptide values in serum (p < 0.0001). These findings indicate an accelerated bone turnover in patients following bone marrow transplantation due to the stimulation of osteoblasts by cyclosporin A. In addition, oestrogen deficiency after total body irradiation may accelerate bone mass loss in female patients.