Osteoporosis after cardiac transplantation

Postoperative Care and Outcomes in Solid-Organ Transplant Patients Undergoing Lower Extremity Fracture Treatment

OBJECTIVES

To determine the postoperative outcomes in solid-organ transplant (SOT) patients undergoing operative treatment of lower extremity fractures.

METHODS

DESIGN

Retrospective comparative study.

SETTING

Academic Level 1 trauma center.

PATIENT SELECTION CRITERIA

Patients who underwent SOT and operative treatment of lower extremity fracture from 2013 to 2021 were identified, excluding pathologic fractures.

OUTCOME MEASURES AND COMPARISONS

Postoperative complications, length of stay, time to death, 90-day and 1-year readmission rates, readmission causes, discharge location, and immunosuppressive regiments.

RESULTS

Sixty-one patients with an average age of 67 years (range 29-88) were included. The mortality rate was 37.7%. The average follow-up was 15.2 months (range of 2 weeks-10 years). The majority of patients (32.8%) had received a liver transplant, and femoral neck fractures constituted the largest fracture group. The average length of stay was 10 days, with the shortest being 1 day and the longest being 126 days (SD 18). The majority of patients (57.3%) were not discharged home. Only 2 suffered from a postoperative complication requiring another procedure: hardware removal and liner exchange for periprosthetic joint infection, respectively. There was a 27.9% 90-day readmission rate with 2 deaths within that period with the most common being altered mental status (29.4%), genitourinary infections (17.6%), repeat falls (11.8%), and low hemoglobin requiring transfusion (11.8%). The longest average time to death analyzed by transplant type was found among lung transplant patients (1076 days, 62.5% mortality), followed by liver transplant patients (949 days, 35.0% mortality), and then kidney transplant patients (834 days, 38.9% mortality). The shortest time to death was 71 days from index procedure.

CONCLUSIONS

Family members of SOT patients undergoing operative treatment of lower extremity fractures should be made aware of the high risk for 90-day readmission postoperatively (27.9%) and overall mortality (12.5%). Providers should be aware of the need for multidisciplinary involvement for inpatient care, monitoring postoperative complications, and facilitating discharge planning.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Lumbar vertebral bone density is decreased in horses with pituitary pars intermedia dysfunction

BACKGROUND

Pathological fractures have been reported in equids with pituitary pars intermedia dysfunction (PPID) but their prevalence and pathogenesis is unknown.

OBJECTIVES

To compare: (1) bone mineral density (BMD) in weight bearing and nonweight bearing bones in PPID+ equids and aged and young PPID- controls; and (2) biomechanical properties of the fourth lumbar vertebral body in PPID+ equids and aged PPID- equids.

STUDY DESIGN

Case-control study: five PPID+ equids and six aged and four young PPID- control horses.

METHODS

PPID status was based on clinical signs and necropsy examination of the pituitary gland (PG). The lumbar vertebral column, right front third metacarpus (MC3), left hind third metatarsus (MT3), and PG were removed after euthanasia. BMD was determined by quantitative computed tomography of regions of interest (ROI) in each bone and biomechanical testing was performed on the fourth lumbar vertebral body. Serum concentrations of parathormone (PTH), ionised Ca++ , 25-hydroxyvitamin D, and osteocalcin (OC) were also measured. Data were analysed using one-way ANOVA and correlation analyses.

RESULTS

BMD of trabecular and cortical regions of interest (ROI) of the third, fourth (L4), and fifth lumbar vertebrae were significantly lower in PPID+ equids as compared with aged (p < 0. 001) and young (p < 0.01) PPID- controls. In contrast, no differences were found in BMD of trabecular or cortical ROIs of MC3 and MT3 between groups. No differences were detected in force at fracture, displacement at fracture, Young's modulus or strain of L4 between PPID+ and aged PPID- horses. No differences were found in serum PTH, ionised Ca++ , 25-hydroxyvitamin D, or OC concentrations between groups.

MAIN LIMITATIONS

Limited number of equids studied and variation in test results.

CONCLUSIONS

BMD of nonweight bearing bones can be decreased with PPID and could increase risk of developing pathological fractures.

The prevalence of osteopenia and osteoporosis after heart transplantation assessed using CT

OBJECTIVE

Osteoporosis is frequently observed in patients after heart transplantation (HT), although the prevalence long-term post-HT is unknown. Most studies investigating bone mineral density (BD) after HT were performed using dual-energy X-ray absorptiometry. In this study BD, including the prevalence of osteopenia and osteoporosis, was investigated using coronary computed tomography (CCT) long-term post-HT. Moreover, risk factors for abnormal BD were investigated.

METHODS

All first CCT scans between February 2018 and June 2020 used for the annual screening for cardiac allograft vasculopathy were included. Retransplantations and scans with not fully imaged vertebrae were excluded. BD was measured as a mean of the BD of three consecutive thoracic vertebrae and categorized into normal BD, osteopenia or osteoporosis. Binary logistic regression was used to find determinants for an abnormal BD. Linear regression was used to explore determinants for the mean Hounsfield unit (HU) value of the BD.

RESULTS

In total, 140 patients were included (median age 55.2 [42.9-64.9] years, 51 (36%) female). Time between HT and CT scan was 11.0 [7.3-16.1] years. In total, 80 (57%), 43 (31%), and 17 (12%) patients had a normal BD, osteopenia, or osteoporosis, respectively. Osteoporotic fracture or vertebrae fractures was seen in 11 (8%) patients. Determinants for an abnormal BD were recipient age (OR 1.10 (1.06-1.14), p<0.001) and prednisolone use (OR 3.75 (1.27-11.01), p=0.016). In linear regression, left ventricular assist device use pre-HT (p=0.024) and time since HT (p=0.046) were additional BD determinants.

DISCUSSION

Osteopenia and osteoporosis are frequently seen on CCT post-HT. More investigation on appropriate measures to maintain a normal BD in these patients are needed.

Effect of neridronate in osteopenic patients after heart, liver or lung transplant: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Transplantation (Tx) is an effective therapeutic option in patients with end-stage organ failure and osteoporosis and related fractures are a recognized complication in these patients. Aim of this study was to evaluate the efficacy of neridronate in patients with reduced bone mass after Tx of the heart, liver or lung.

METHODS

In this multicenter randomized double-blind controlled trial (RCT), 22 patients were treated with neridronate (25 mg i.m./month) and 17 received placebo. All patients received daily oral calcium (500 mg) and vitamin D (400 IU). Dual-energy X-ray absorptiometry (DXA) was evaluated at 0, 6 and 12 months and markers of bone turnover at 0, 3, 6, 9 and 12 months.

RESULTS

Thirty-nine patients (11 heart Tx, 21 liver Tx, 7 lung Tx), aged 49.3±9.1 years, with a T-score <-2.0 SD at lumbar spine or femoral level were included. In neridronate-treated patients, a significant increase in lumbar bone mineral density (BMD) was observed after 12 months vs. placebo control (0.92±0.13 g/cm² vs. 0.84±0.08 g/cm²; P=0.005). Femur and hip BMD remained unchanged between groups. Total alkaline phosphatase, bone alkaline phosphatase and beta-cross-laps significantly decreased over the 12 months in neridronate-treated patients vs. placebo, respectively (107.4±74 U/L vs. 157.6±107.1 U/L, P=0.002; 5.7±3.3 µg/L vs. 11.7±4.3 µg/L, P<0.001 and 0.25±0.13 ng/mL vs. 0.73±0.57 ng/mL, P<0.001). No difference was observed between neridronate and placebo groups regarding safety profile.

CONCLUSIONS

This is the first RCT that demonstrates the efficacy of neridronate in increasing bone density and reducing bone turnover in organ Tx recipients with significant skeletal morbidity.

Bone disease following solid organ transplantation: A narrative review and recommendations for management from The European Calcified Tissue Society

INTRODUCTION

Solid organ transplantation is an established therapy for end-stage organ failure. Both pre-transplantation bone disease and immunosuppressive regimens result in rapid bone loss and increased fracture rates.

METHODS

The European Calcified Tissue Society (ECTS) formed a working group to perform a systematic review of existing literature on the consequences of end-stage kidney, liver, heart, and lung disease on bone health. Moreover, we assessed the characteristics of post-transplant bone disease and the skeletal effects of immunosuppressive agents and aimed to provide recommendations for the prevention and treatment of transplantation-related osteoporosis.

RESULTS

Characteristics of bone disease may differ depending on the organ that fails, but patients awaiting solid organ transplantation frequently depict a wide spectrum of bone and mineral abnormalities. Common features are a decreased bone mass and impaired bone strength with consequent high fracture risk, all of which are aggravated in the early post-transplantation period.

CONCLUSION

Both the underlying disease leading to end-stage organ failure and the immunosuppression regimens implemented after successful organ transplantation have detrimental effects on bone mass, quality and strength. Given existing ample data confirming the high frequency of bone disease in patients awaiting solid organ transplantation, we recommend that all transplant candidates should be assessed for osteoporosis and fracture risk and, if indicated, treated before and after transplantation. Since bone loss in the early post-transplantation period occurs in virtually all solid organ recipients and is associated with glucocorticoid administration, the goal should be to use the lowest possible dose and to taper and withdraw glucocorticoids as early as possible.

Protective effects of 2,3,5,4-tetrahydroxystilbene-2-o-β-D-glucoside against osteoporosis: Current knowledge and proposed mechanisms

AIM

The aim of this study was to explore the mechanism underlying the protective effects of 2,3,5,4-tetrahydroxystilbene-2-o-β-D-glucoside (TSG) against osteoporosis.

METHOD

MC3T3-E1 mouse osteoblast precursor cells were used to analyze the protective effects of TSG on osteoblast apoptosis and differential inhibition induced by oxidative stress to determine the gene expression of forkhead transcription factor FKHRL1 (FoxO3a), T cell factors (TCFs), and downstream genes. A mouse model was used to assess the protective effects of TSG on ovariectomy-induced osteoporosis as well as on Cell Counting Kit-8 (CCK) gene expression, including that of FoxO3a. The mechanism underlying the protective effects of TSG against osteoporosis was further explored using high-throughput sequencing data.

RESULTS

A CCK-8 assay in MC3T3-E1 cells and hematoxylin and eosin staining in mouse tissue indicated that cell viability and bone tissue development were inhibited by oxidative stress and ovariectomy and that TSG neutralized or attenuated this effect. The expression levels of FoxO3a, TCF, and downstream genes and the indices of oxidative stress were the same in MC3T3-E1 cells and the bone tissues of the mouse model. Bioinformatics analysis indicated that the cardiac muscle contraction and chemokine signaling pathway were disturbed in MC3T3-E1 cells treated with hydrogen peroxide. Gene ontology-biological process analysis revealed the influence of TSG treatment.

CONCLUSION

Osteoporosis and cardiac diseases appear to share a common mechanism. In addition to Wnt/FoxO3a signaling, the immune system and the chemokine signaling pathway may contribute to the protective mechanism of TSG.

Ethnic Differences in Osteoporosis After Cardiac Transplantation

Cardiac transplantation is associated with a high risk of fracture. African Americans (AAs) are believed to have a lower risk of osteoporosis than Caucasians, but it is not clear whether they are also protected from osteoporosis resulting from the use of glucocorticoids and/or organ transplantation. We examined possible ethnic differences in 33 cardiac transplant recipients (16 AAs) in a cross-sectional analysis. In addition to bone mineral density and vertebral fracture assessment, we also compared biochemical variables, trabecular bone score, total body dual-energy X-ray absorptiometry, and disability. Overall fracture rates were low in both groups, with only 6 total subjects with fractures on vertebral fracture assessment or history of fracture. While T-scores were similar between groups, Z-scores were lower in AA with the difference reaching statistical significance when controlling for important covariates. The trabecular bone score was also lower in AAs than in Caucasians even when adjusting for age and tissue thickness (1.198 ± 0.140 vs 1.312 ± 0.140, p = 0.03). While AAs are generally thought to be protected from osteoporosis, our study instead suggests that AAs may be at higher risk of bone deterioration after cardiac transplantation and may need to be managed more aggressively than suggested by current guidelines.

Sirolimus and tacrolimus rather than cyclosporine A cause bone loss in healthy adult male rats

The aim of this work was to study the effects of cyclosporine (CsA), tacrolimus (FK-506), and rapamycin (RAPA) on bone mass, femoral microstructure, femoral biomechanical properties, and bone remodeling in healthy adult male rats.

Forty-eight 5-month-old male Wistar rats were used. CsA (2 mg/kg/day), FK-506 (3 mg/kg/day), RAPA (1.25 mg/kg/day), or water (0.5 ml/rat/day, control group) were administered orally for 3 months.

After sacrifice, mean values of immunosuppressants in blood were: CsA (670.4 ng/ml), FK-506 (19.2 ng/ml), and RAPA (4.8 ng/ml). Levels of biochemical parameters were normal in all groups. Femoral BMD was decreased in FK-506 and RAPA groups and lumbar BMD in FK-506 group. Trabecular volume fraction (BV/TV) decreased only in FK-506 group. RAPA and CsA affected femoral cortical structure, but FK-506 did not. FK-506 produced an increase in bone remodeling, and CsA a decrease. FK-506 group showed a decrease in biomechanical parameters relative to all groups. RAPA group showed a decrease in ultimate stress vs control group, and CsA group presented an increase in biomechanical parameters versus control group.

We found that administration of both RAPA and FK-506 as monotherapy for healthy rats produced osteopenia. CsA treatment only produces slight damages in the cortical zone of the femur.

Incidence of fractures after cardiac and lung transplantation: a single center experience

Osteoporotic fractures are well-known complications of organ transplantation. Fracture rates up to 35% have been previously reported following heart and lung transplantations. Our institutional pretransplant protocols include DXA scans, vitamin D screening, and appropriate antiresorptive therapy. We aimed to assess the incidence of fragility fractures following cardiac or lung transplantation. In a retrospective study 210 electronic medical records of patients who underwent LT (110 men, 100 women) and 105 HT (88 men, 17 women) between 2005 and 2010 were analyzed. Both clinical and radiographic fractures were recorded. DXA scans were obtained immediately after transplant. 17 out of 210 LT patients (8.0%) had fractures after transplantation and 9 out of 105 HT patients (8.6%) had fractures. The median time to the first fracture was 12 months and the mean time was 18 months for both LT and HT. In the HT recipients, the median femoral neck T score was statistically lower in the fracture group versus the nonfracture group. Similar results were seen in the LT patients. Conclusion. Our findings demonstrate a much lower incidence of fractures in heart and lung transplant recipients in comparison with earlier reports. Comprehensive bone care and early initiation of antiresorptive therapy are possible contributors to these improved outcomes.

Gender- and dose-related effects of cyclosporin A on hepatic and bone metabolism

Previous data have shown gender-related differences in the skeletal effects of the immunosuppressive drug cyclosporin A (CsA) in rats. To test the hypothesis that the gender-related skeletal effects of CsA are caused by gender-specific metabolism of this drug, we treated aged male and female sham-operated, gonadectomized (GX) as well as sex hormone-supplemented GX rats with 5 mg/kg CsA three times per week for 2 months, and analyzed the bone phenotype as well as the concentrations of CsA and its major metabolites AM1, AM1c, AM9, and AM4N in blood, urine, and liver tissue. CsA treatment induced high turnover osteopenia in males, but not females. Male rats showed several-fold higher CsA and CsA metabolite blood levels compared with females. Renal clearance data revealed that CsA undergoes selective tubular reabsorption in male, but not female rats. However, a mathematical modeling approach demonstrated that the higher CsA blood levels in males were almost exclusively caused by a 6-fold lower hepatic clearance rate compared with females. In addition, we subcutaneously treated female rats with up to 6-fold higher doses of CsA. Similar to males, high dose CsA induced high turnover osteopenia in female rats. Our data show that the gender-related differences in the skeletal effects of CsA are caused by a higher hepatic clearance rate for CsA in female compared to male rats, and not by a differential skeletal response to CsA. Moreover, our study indicates that CsA blood levels of ≤200 ng/ml measured by HPLC do not induce high turnover osteopenia in aged rats.

Densitometric threshold and vertebral fractures in heart transplant patients

BACKGROUND

Bone disease is one of the major complications of solid organ transplantation, causes considerable morbidity, and most patients are treated with immunosuppressant drugs after graft. The majority of studies reported rapid bone loss and an increased incidence of fractures after transplantation. The aim of our study was to evaluate osteoporosis and fracture prevalence, bone metabolism, and the effect of immunosuppressant agents on bone after heart transplantation.

METHODS

We planned a cross-sectional study in 180 heart transplant patients recruited from 3 different centers with a less than 10 years from graft. Each patient underwent a densitometric scan, and in 157 of them, an x-ray of the spine was performed to evaluate fractures. Biochemical assessment of bone metabolism was made at the time of the visit. Physical activity, diet, and calcium intake were evaluated using a specific questionnaire.

RESULTS

Vertebral fractures were diagnosed in 40% of subjects, but densitometric osteoporosis was observed only in 13% of spine and in 25% of hip scans. Interestingly, increasing T-score threshold up to -1.5 standard deviation, the prevalence of fractured patient improved significantly, reaching 60% in both genders. Bone content was inversely correlated with glucocorticoids, while a positive correlation was found with cyclosporine A. Almost all subjects had vitamin D deficiency.

CONCLUSIONS

Standard densitometric criteria are unreliable to identify bone fragility after transplantation, and a different threshold (-1.5 standard deviation) should be considered. Transplanted patients should be adequately supplemented with vitamin D, and the effects of immunosuppressant agents on bone need further investigation.

Trauma to transplanted kidney with open fractures: Report of a case

A 45 year-old man, who had undergone kidney transplantation 7 years prior, was admitted to hospital after a motorcycle accident. The patient was conscious, hemodynamically stable, and had suffered open tibia and femur fractures, as well as closed pubic arm fractures. He had gross hematuria and radiologic study revealed a 3.5 cm length laceration on the transplanted kidney. His renal functions and hematuria recovered after intensive care. He required 2 surgeries for the open fractures but his general condition worsened after the surgical interventions. Acinetobacter, Candida albicans and pseudomonas aeruginosa were determined by blood cultures. Immunosupressive drugs (cyclosporine, prednisolone and azathioprine) were stopped. Despite intensive care, the patient died of sepsis 17 days post trauma. Open fractures of long bones provide a higher risk of sepsis in transplant patients than closed fractures.

Bone mineral status in pediatric heart transplant recipients: a retrospective observational study of an "at risk" cohort

There is a paucity of literature assessing the burden of bone loss in PHT recipients. We sought to describe the bone mineral status in PHT recipients by doing a retrospective medical record review of those who underwent evaluation of BMD when clinically indicated. Data collected included patient demographics, BMD evaluations, serum calcium, phosphorus, alkaline phosphatase, cumulative steroid dose, osseous complications and their management. Of 149 PHT recipients, 26 underwent BMD evaluation. This evaluation was done at a median of 3.4 yrs after PHT. There total serum calcium, phosphorus and alkaline phosphatase were similar at transplant and BMD study. The median BMD Z-scores were: whole body -0.09 (1.5 to -5.13) and lumbar spine -1.1 (1.5 to -5.16). Bone loss (Z-score <-1) was present in 14 (53.8%). Three patients had spinal fractures and/or avascular necrosis of various bones. Treatment included calcitrol and bisphosphonates; and vertebroplasty for spinal fracture. Bone loss was present in a significant proportion of PHT recipients and may be associated with fractures and avascular necrosis. More than half of our "at risk" cohort had bone loss. Careful surveillance of these patients should be performed to prevent morbidity.

Dietary vitamin K2 supplement improves bone status after lung and heart transplantation

BACKGROUND

Osteoporosis is a problem after transplantation. Studies since the last year indicate that vitamin K plays a role in optimal bone health. The aim of this randomized, double blind, prospective longitudinal study was to investigate the effect of a dietary supplement with vitamin K2 (180 microg menakinon-7) on bone mass, the first year after lung and heart transplantation.

METHODS

After preoperative baseline investigation of bone mass and bone-related biochemistry, 35 lung and 59 heart recipients were postoperatively randomized to vitamin K2 or placebo and reinvestigated the following year.

RESULTS

In all recipients, 1 year after solid organ transplantation, the difference between vitamin K2 and placebo for the lumbar spine (L2-L4) bone mineral density (BMD) was 0.028 (SE 0.014) g/cm(2), P=0.055 and for L2 to L4 bone mineral content was 1.33 (SE 1.91) g/cm(2) (P=0.5). In lung recipients separately, the difference for bone mineral content was 3.39 g (SE 1.65), P=0.048 and in heart recipients 0.45 (SE 0.02) g, P=0.9 after controlling for baseline measures. In a forward stepwise linear regression analysis fitted to model differences in the L2 to L4 BMD, controlled for possible confounding variables (including use of bisphosphonate), and the only significant predictors were organ (B=-0.065 g/cm(2), P<0.001) and vitamin K2 (B=0.034 g/cm(2), P=0.019). Insufficient vitamin D status was common, and the parathyroid hormone was highest in the K2 group indicating a higher need for vitamin D.

CONCLUSIONS

One year of vitamin K2 supplement suggest a favorable effect on lumbar spine BMD with different response in lung and heart recipients. Vitamin D status should receive more attention.

CRHR1 polymorphisms predict bone density in survivors of acute lymphoblastic leukemia

PURPOSE

Corticosteroids are a critical component of therapy for acute lymphoblastic leukemia (ALL) but are associated with late effects, such as osteoporosis. Risk factors remain poorly defined. Because CRHR1 polymorphisms have been associated with other corticosteroid effects, our goal was to define whether CRHR1 polymorphisms predict which patients with ALL are likely to develop bone mineral deficits.

PATIENTS AND METHODS

The mean bone mineral density z scores of 309 long-term survivors of ALL were determined by quantitative computed tomography of the trabecular lumbar spine. We analyzed whether CRHR1 genotypes, adjusted for sex, ALL treatment regimen, and weight, could predict bone density.

RESULTS

We found that three single nucleotide polymorphisms (SNPs), all in linkage disequilibrium, were associated with bone density in a sex-specific manner. Bone density was lower in males (P = .001), in nonblack patients (P < .08), in those who were not overweight (P < .001), and in those who received intensive antimetabolites and glucocorticoids (P < .001). After adjustment for these features, the G allele at the rs1876828 SNP was associated with lower z scores (P = .02) in males but tended to have the opposite association in females (P = .09).

CONCLUSION

CRHR1 polymorphisms may impact the risk of bone density deficits in patients treated with corticosteroids and antimetabolites in a sex-specific manner.

Unexpected low incidence of vertebral fractures in heart transplant recipients: analysis of bone turnover

Heart transplantation (HTX) is associated with a reduction in bone mineral density (BMD). Different markers of bone metabolism have been used, and the applied immunosuppressive regimens have also changed over time. This study was performed to re-investigate bone metabolism in HTX recipients. Twenty-five HTX recipients were compared with 25 HTX candidates in respect of biochemical parameters of bone metabolism, BMD, and the frequency of fractures for 1 year. Osteopenia or osteoporosis was observed in approximately two-thirds of the HTX recipients. Nevertheless, only three (12%) HTX recipients developed a vertebral fracture within 1 year after transplantation; no peripheral fractures occurred. Compared with HTX candidates, HTX recipients had lower serum levels of osteocalcin, and higher serum levels of cross-linked-N-telopeptide of type I collagen (NTX). In HTX recipients, osteocalcin initially reached a nadir, increased during the first 3 months, and decreased thereafter. Bone-specific alkaline phosphatase initially increased and then decreased. Serum levels of NTX and parathyroid hormone remained high throughout the year. Despite a high bone turnover, an unexpectedly low rate of vertebral fractures was registered. Nevertheless, each fragility fracture is a serious complication and we need to take steps to prevent this complication.

Oral cyclosporin plus topical corticosteroid therapy diminishes bone mass in children with eczema

Topical corticosteroids remain the most common treatment for eczema; however, it is uncertain whether long-term use of these agents has any adverse effect on bone mass. Cyclosporin is very useful in patients with severe atopic dermatitis who have failed conventional therapy. It has been shown to induce bone loss. We compared 43 children with severe eczema who were using topical corticosteroids with 73 healthy children. Of the 43 patients, six were also taking cyclosporin. Bone mineral density was measured in the lumbar spine and in the femoral neck using dual-energy X-ray absorptiometry. In multivariate analysis, subjects with eczema had lower lumbar spine bone mineral density (-0.03 g/cm(2); p = 0.015) and bone mineral apparent density (-0.01 g/cm(3); p = 0.008) but higher FN BMAD (+0.02 g/cm(3); p = 0.029) compared with controls. Patients with eczema on topical corticosteroids who had used cyclosporin had lower lumbar spine bone mineral apparent density (-0.01; p = 0.006) compared with those only on topical corticosteroids in both adjusted and unadjusted analysis. In conclusion, children with severe eczema have decreased lumbar spine bone mass, which is primarily mediated by cyclosporin use rather than by topical corticosteroid use. This effect is likely to lead to a modest increase in the risk of wrist and forearm fractures in children using this agent.

Bone Fractures After Cardiac Transplantation

OBJECTIVE

Bone loss and bone fractures are disabling complications after heart transplantation. Severe bone loss happens mainly during the first year posttransplantation. Steroids and cyclosporine alter bone metabolism in several ways. To counterbalance these effects, antiresorptive therapy is provided to these patients. The objective of this study was to assess the frequency of bone fractures after heart transplantation, considering previous comorbidities, immunosuppressive therapy, and osteoprotective treatment.

METHODS

From 1993 to 2005, 443 consecutive heart transplant recipients were followed for the occurrence of bone fractures, immunosuppressive therapy, clinical conditions, and antiresorptive treatment.

RESULTS

There were 41 fractures in 34 patients (7.6%, group I). The remainder of patients formed group II. Fractures commonly involved the lumbar spine. Postmenopausal women had more fractures than other patients (20.6% vs 7.8%, P = .02). When the initial immunosuppressive regimen included tacrolimus, fractures did not happen (P = .01, vs other regimens). Osteoprotective therapy was administered to 91.2% of patients in group I and 79% in group II (P = .08). Mean interval from transplantation to the first fracture was 1131.5 days. Overweight patients had a 61.8% incidence of fracture.

CONCLUSIONS

Our series showed a low frequency of bone fractures. Postmenopausal women and overweight patients had more fractures. An initial immunosuppressive regimen using tacrolimus was associated with lower fracture rates.

Transplantation osteoporosis

In the past two decades, there has been a rapid increase in the number of organ transplanted worldwide, including Brazil, along with an improvement in survival and quality of life of the transplant recipients. Osteoporosis and a high incidence of fragility fractures have emerged as a complication of organ transplantation. Many factors contribute to the pathogenesis of osteoporosis following organ transplantation. In addition, most patients have some form of bone disease prior to transplantation, which is usually related to adverse effects of end-stage organ failure on the skeleton. This chapter reviews the mechanisms of bone loss that occur both in the early and late post-transplant periods, as well as the features specific to bone loss after kidney, lung, liver, cardiac and bone marrow transplantation. Prevention and treatment for osteoporosis should be instituted prior and in the early and late phase after transplantation, and will also be addressed in this article.

Cyclosporin A elicits dose-dependent biphasic effects on osteoblast differentiation and bone formation

Cyclosporin A (CsA) is thought to prevent immune reactions after organ transplantation by inhibiting calcineurin (Cn) and its substrate, the Nuclear Factor of Activated T Cells (NFAT). A dichotomy exists in describing the effects of CsA on bone formation. The concept that the suppression of Cn/NFAT signaling by CsA inhibits bone formation is not entirely supported by many clinical reports and laboratory animal studies. Gender, dosage and basal inflammatory activity have all been suggested as explanations for these seemingly contradictory reports. Here we examine the effects of varying concentrations of CsA on bone formation and osteoblast differentiation and elucidate the role of NFATc1 in this response. We show that low concentrations of CsA (<1 microM in vitro and 35.5 nM in vivo) are anabolic as they increase bone formation, osteoblast differentiation, and bone mass, while high concentrations (>1 microM in vitro and in vivo) elicit an opposite and catabolic response. The overexpression of constitutively active NFATc1 inhibits osteoblast differentiation, and treatment with low concentrations of CsA does not ameliorate this inhibition. Treating osteoblasts with low concentrations of CsA (<1 microM) increases fra-2 gene expression and protein levels in a dose-dependent manner as well as AP-1 DNA-binding activity. Finally, NFATc1 silencing with siRNA increases Fra-2 expression, whereas NFATc1 overexpression inhibits Fra-2 expression. Therefore, NFATc1 negatively regulates osteoblast differentiation, and its specific inhibition may represent a viable anabolic therapy for osteoporosis.

Comparison of alendronate vs alendronate plus mechanical loading as prophylaxis for osteoporosis in lung transplant recipients: a pilot study

BACKGROUND

Osteoporosis is known to complicate outcomes after lung transplantation (Tx).

METHODS

To determine the efficacy of bisphosphonate therapy combined with the osteogenic stimulus of mechanical loading, 30 lung transplant recipients (LTRs) were randomly assigned either to alendronate (10 mg/day; n = 10), alendronate (10 mg/day) + resistance exercise (n = 10) or to a control group (n = 10). Alendronate was initiated at 7 days after Tx. Bone mineral density (BMD) of the lumbar spine was measured by dual-energy X-ray absorptiometry before and 2 and 8 months after Tx. Resistance training was initiated at 2 months after Tx and consisted of lumbar extension exercise performed 1 day/week for 6 months.

RESULTS

Lumbar BMD decreased significantly to below pre-transplant baseline at 2 months after Tx in controls (-12.5 +/- 2.1%), but not in the alendronate (1.5 +/- 1.2%) or alendronate + training (1.5 +/- 0.9%) groups. At 8 months after Tx, lumbar BMD in controls was 14.1 +/- 3.9% below baseline (p < or = 0.05), but was 1.4 +/- 1.1% above baseline in alendronate recipients (p > or = 0.05). The alendronate + training group showed a significantly increased lumbar BMD with values 10.8 +/- 2.3% greater than before Tx.

CONCLUSIONS

These results suggest that resistance exercise plus alendronate is more effective than alendronate alone in restoring BMD. Anti-osteoporosis therapy in LTRs should include both an anti-resorptive agent and an osteogenic stimulus, such as mechanical loading.

Bone health in children and adolescents after allogeneic stem cell transplantation

BACKGROUND

This cross-sectional study evaluated the overall bone health and the prevalence of vertebral complications after stem cell transplantation (SCT) in prepubertal children and adolescents.

METHODS

A total of 44 children and adolescents (median age, 10 years) were evaluated at a median of 3.8 years after SCT for areal bone mineral density (aBMD) with dual-energy X-ray absoptiometry and for vertebral fractures with instant vertebral assessment. Pretransplant and posttransplant medications and nutritional parameters were recorded, and plasma levels of vitamin D, calcium, phosphate, and parathormone were measured.

RESULTS

Of the 44 patients, 16 (36%) had a BMD Z-score of <-1.0. The patients with low BMD did not differ from the others with regard to their clinical or biochemical characteristics. Prepubertal patients had better BMD Z-scores at all sites compared with pubertal or postpubertal subjects. This was evident especially at the hip, in which the median aBMD Z-score in prepubertal patients (-0.2; range, -0.5 to +1.7) was found to be significantly higher than in pubertal (-1.1; range, -1.5 to +0.4) and postpubertal (-1.1; range, -2.6 to +0.5) patients (P = .03). Five patients (11%) had a history of peripheral fractures. Nine patients (20%) had vertebral compression fractures, which were asymptomatic in 7 patients.

CONCLUSIONS

Approximately one-third of patients who had undergone allogeneic SCT in childhood were found to have a reduced BMD before reaching adulthood. This was due in part to inadequate BMD gain during the pubertal years. The high prevalence of asymptomatic vertebral compression fractures calls for the systematic assessment of spinal health during the posttransplantation follow-up.

Bone Mineral Density in Long-Term Chinese Heart Transplant Recipients: A Cross-Sectional Study

Osteoporosis, which usually peaks during 6 to 12 months after transplantation, remains an important concern after heart transplantation. Immunosuppressants contribute to this phenomenon. Glucocorticoids are well documented to cause bone loss, but the role of cyclosporine (CsA) remains controversial, especially among long-term recipients on low doses of steroid. We herein report a cross-sectional study of bone mineral density (BMD) among long-term Chinese heart transplant recipients. We enrolled 41 patients of mean age 50.15 +/- 13.58 years with a mean follow-up of 57.02 months. Lumbar spine and femoral neck BMD were measured by dual energy x-ray absorptiometry. Trough CsA levels (C(0)) and markers of mineral metabolism, including bone-specific alkaline phosphatase and urinary N-telopeptide, were determined by immunoassay. Sixty six percent of subjects showed bone loss at the femoral neck, significantly more than those in the lumbar spine. Those receiving a higher CsA dosage (<2.5 mg/kg/d) showed greater femoral neck BMD, but lower serum creatinine values. Our results demonstrated that bone loss remains long after transplantation, though bone markers are within normal limits.

Prevention and treatment strategies for glucocorticoid-induced osteoporotic fractures

Glucocorticoids are the most common cause of drug-related osteoporosis. We reviewed current evidence on risk factors for glucocorticoid-induced osteoporosis (GIOP) and prevention and treatment of GIOP-related fractures. Guidelines for GIOP management published since 2000 were also reviewed. Significant bone loss and increased fracture risk is seen with daily prednisone doses as low as 5 mg. Alternate-day glucocorticoid therapy can lead to similar bone loss. No conclusive evidence exists for a safe minimum dose or duration of glucocorticoid exposure. Physicians should consider risk factors for involutional osteoporosis such as older age, postmenopausal status, and baseline bone density measurements as they assess patients for prevention or treatment of GIOP. Bisphosphonates were reported to reduce GIOP-related vertebral fractures, but inconclusive data exist for hip fractures associated with glucocorticoid use. Hormone replacement therapy and parathyroid hormone analogs are effective in preserving bone density in GIOP. The risk of osteoporosis and fractures should be routinely assessed in patients receiving glucocorticoid therapy. Effective prevention and treatment options are available and can result in meaningful reduction of GIOP-related morbidity and mortality. Current guidelines for GIOP management recommend bisphosphonates, especially alendronate and risedronate, as first-line agents for GIOP, and these guidelines propose the preventive use of bisphosphonates early in the course of glucocorticoid therapy in high-risk patient subgroups.

Calcium/calmodulin signaling controls osteoblast growth and differentiation

Ca2+ is a ubiquitous intracellular messenger responsible for controlling numerous cellular processes including fertilization, mitosis, neuronal transmission, contraction and relaxation of muscles, gene transcription, and cell death. At rest, the cytoplasmic Ca2+ concentration [Ca2+]i is approximately 100 nM, but this level rises to 500-1,000 nM upon activation. In osteoblasts, the elevation of [Ca2+]i is a result of an increase in the release of Ca2+ from endoplasmic reticulum and/or extracellular Ca2+ influx through voltage gated Ca2+ channels. Many of the cellular effects of Ca2+ are mediated by the Ca2+ binding protein, calmodulin (CaM). Upon binding up to four calcium ions, CaM undergoes a conformational change, which enables it to bind to specific proteins eliciting a specific response. Calmodulin kinase II (CaMKII) is a major target of the Ca(2+)/CaM second messenger system. Once bound to Ca(2+)/CaM, the multimeric CaMKII is released from its autoinhibitory status and maximally activated, which then leads to an intraholoenzyme autophosphorylation reaction. Calcineurin (Cn) is another major target protein that is activated by Ca(2+)/CaM. Cn is a serine-threonine phosphatase that consists of a heterodimeric protein complex composed of a catalytic subunit (CnA) and a regulatory subunit (CnB). Upon activation, Cn directly binds to, and dephosphorylates nuclear factor of activated T cells (NFAT) transcription factors within the cytoplasm allowing them to translocate to the nucleus and participate in the regulation of gene expression. This review will examine the potential mechanisms by which calcium, CaM, CaMKII, and Cn/NFAT control osteoblast proliferation and differentiation.

Comparison of Calcitonin versus Calcitonin + Resistance Exercise as Prophylaxis for Osteoporosis in Heart Transplant Recipients

BACKGROUND

Rapid bone loss occurs early after heart transplantation. There is no standard therapeutic intervention to prevent osteoporosis in heart transplant recipients (HTR). The purpose of this study was to determine the effectiveness of a regimen combining the antiresorptive properties of nasal calcitonin with the osteogenic stimulus of resistance exercise.

METHODS

Eighteen candidates for heart transplantation were randomly assigned either to a group that received calcitonin and participated in 6 months of resistance exercise (n=10) or to a group that received only calcitonin (n=8). Calcitonin therapy (200 IU daily for 8 months) was initiated 48 hr after transplantation. Resistance exercise was initiated 2 months after transplantation. Bone mineral density (BMD) of the total body, femur neck, and lumbar vertebra (L2-3) were assessed before, and at 2 and 8 months after transplantation.

RESULTS

Total body and femur neck BMD did not decrease (P>or=0.05) below pretransplantation values at 2 months after transplantation in either group. BMD of the lumbar spine was significantly (P<or=0.05) and comparably decreased at 2 months after transplantation in the calcitonin (-10.1+/-1.8%) and calcitonin + training groups (-12.9+/-2.7%). At 8 months after transplantation lumbar BMD was -16.9% below pretransplant values in the calcitonin group. In contrast, lumbar BMD was restored to within 5% of pretransplant levels in the calcitonin + training group.

CONCLUSIONS

Calcitonin attenuates BMD loss in the total body and femur neck but not in trabecular bone of the lumbar vertebra. Mechanical loading, through progressive resistance exercise, is an osteogenic stimulus in HTR.

Incidence and predictors of fractures in children after solid organ transplantation: a 5-year prospective, population-based study

In this population-based prospective follow-up study, children undergoing solid organ transplantation had a highly elevated risk for fractures: The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. Thus, screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.

INTRODUCTION

The incidence and predictors of fractures after solid organ transplantation are not well documented in the pediatric age group.

MATERIALS AND METHODS

A total of 196 children, which is 93% of patients surviving kidney, liver, and heart transplantation in our country, participated in a retrospective chart review at enrollment followed by a 5-year prospective follow-up study between January 1999 and December 2004. Hospital and medical records were reviewed. All children underwent clinical examinations and answered questionnaires concerning fracture history at the beginning and at the end of the prospective follow-up. Radiographs of the thoracic and lumbar spine were obtained. The fracture incidence was compared with data obtained from public health registries.

RESULTS

Seventy-five (38%) of the transplant patients suffered from a total of 166 fractures after organ transplantation. The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. The age- and sex-adjusted hazard ratios (95% CI) were 61.3 (40.7-92.4) for vertebral, 17.9 (8.96-35.8) for symptomatic vertebral, 0.99 (0.65-1.50) for nonvertebral, and 2.90 (2.25-3.73) for all fractures in the patients compared with the control population. In a multivariate analysis, older age (hazard ratio [95% CI]; 2.02 [1.07-3.83]), male sex (2.15 [1.22-3.81]), liver transplantation (1.78 [1.01-3.14]), and fractures before transplantation (2.02 [0.92-4.47]) were the most significant independent risk factors.

CONCLUSIONS

Children undergoing solid organ transplantation have a highly elevated risk for fractures. Screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.

Hyperparathyroidism in dogs with hyperadrenocorticism

OBJECTIVES

To assess the effect of canine hyperadrenocorticism (HAC) on parathyroid hormone (PTH), phosphate and calcium concentrations.

METHODS

PTH concentrations and routine biochemical parameters were measured in 68 dogs with HAC. Ionised calcium was measured in 28 of these dogs. The results obtained were compared with an age- and weight-matched group of 20 hospital patients that did not show signs of HAC.

RESULTS

There were significant differences between the PTH, phosphate, alkaline phosphatase, creatinine and albumin concentrations between the two groups. Total and ionised calcium concentrations were not significantly different. Most of the dogs (92 per cent) with HAC had PTH concentrations that were greater than the reference range (10 to 60 pg/ml), and in 23 dogs they were greater than 180 pg/ml. There were significant positive correlations between the PTH and basal cortisol, post-adrenocorticotropic hormone (ACTH) cortisol and alkaline phosphatase concentrations, and also the phosphate and post-ACTH cortisol concentrations.

CLINICAL SIGNIFICANCE

Adrenal secondary hyperparathyroidism is a cause of increased PTH concentrations and may be associated with abnormalities in calcium and phosphate metabolism in dogs with HAC. The findings of this study could explain why canine HAC may cause clinical signs such as calcinosis cutis that are associated with altered calcium metabolism.

Osteoporosis in Adult Survivors of Adolescent Cardiac Transplantation May Be Related to Hyperparathyroidism, Mild Renal Insufficiency, and Increased Bone Turnover

BACKGROUND

Osteoporosis is common in adults who undergo cardiac transplantation. We hypothesized that adolescent cardiac transplant recipients also develop osteoporosis, which would persist into adulthood.

METHODS

We evaluated 9 adult survivors of adolescent cardiac transplantation, aged 21-32, in a cross-sectional, case-control study comparing bone mineral density, indices of mineral metabolism, and bone turnover markers.

RESULTS

Osteoporosis (Z score < or = -2.0) was present in 56% of transplant recipients at the lumbar spine, 33% at the femoral neck, and 100% at the one-third radius. Subjects had mean bone mineral density Z scores of -2.3 +/- 0.9 at the spine, -1.6 +/- 0.7 at the femoral neck, and -3.2 +/- 0.7 at the one-third radius, significantly lower than controls at all sites (p < 0.001). Serum creatinine and vitamin D metabolites were normal and did not differ between subjects and controls. Serum calcium was lower, blood urea nitrogen was elevated, and creatinine clearance tended to be lower in transplant recipients. Parathyroid hormone (PTH) levels were 3-fold higher in subjects than controls, and 75% of subjects had elevated PTH levels. Markers of bone turnover were significantly higher in subjects than controls.

CONCLUSIONS

Adult survivors of adolescent cardiac transplantation have mild renal insufficiency, secondary hyperparathyroidism, and biochemical evidence of increased bone turnover. Osteoporosis is common in these patients, particularly at the one-third radius, a site sensitive to the catabolic effects of sustained excessive PTH secretion. We conclude that adult survivors of adolescent cardiac transplantation should be evaluated for hyperparathyroidism and osteoporosis.

Effect of Long-Term Calcitonin Administration on Steroid-Induced Osteoporosis after Cardiac Transplantation

BACKGROUND

Early, rapid bone loss and fractures after cardiac transplantation are well-documented complications of steroid administration; therefore, we undertook this study on the effects of long-term calcitonin on steroid-induced osteoporosis.

METHODS

Twenty-three heart transplant recipients on maintenance immunosuppression with cyclosporine, mycophenolate mofetil and prednisone were retrospectively studied. All patients received long-term prophylactic treatment with elemental calcium and vitamin D. Twelve (52.2%) patients also received long-term intranasal salmon calcitonin, whereas 11 (47.8%) received none. Bone mineral density and vertebral fractures were assessed at yearly intervals. Statistical comparisons between each group's bone loss during the first year and in the early (1 to 3 years), intermediate (4 to 6 years) and late (7+ years) post-transplantation periods were done.

RESULTS

Lumbar spine bone loss was significant during the early follow-up period in the group not receiving calcitonin (0.744 +/- 0.114 g/cm(2) vs 0.978 +/- 0.094 g/cm(2) [p = 0.002]). The calcitonin group showed bone mineral density (BMD) levels within normal average values throughout the study period. BMD increased in the no-calcitonin group during the intermediate (4 to 6 years) and late (7+ years) follow-up periods, with values approaching normal average and no significant difference between the 2 groups (0.988 +/- 0.184 g/cm(2) vs 0.982 +/- 0.088 g/cm(2) [p = 0.944] and 0.89 +/- 0.09 g/cm(2) vs 1.048 +/- 0.239 g/cm(2) [p = 0.474], respectively).

CONCLUSIONS

Prophylactic treatment with intranasal salmon calcitonin prevents rapid bone loss associated with high-dose steroids early after cardiac transplantation. Long-term administration does not seem warranted in re-establishing BMD.

Reduced bone mineral density in male renal transplant recipients: evidence for persisting hyperparathyroidism

BACKGROUND

Osteoporosis is increasingly recognized as a major source of morbidity following renal transplantation. The aim of this cross-sectional study was to determine the prevalence of osteoporosis in a cohort of male transplant recipients and examine factors that may influence their bone loss.

METHODS

Bone mineral density (BMD) and biochemical markers of bone metabolism were measured in 134 out of 154 male renal allograft recipients in our center.

RESULTS

The mean age of the patients was 49.7 years (range 26-76) with a median of 6 years post-transplant. Only 17% had normal BMD, 30% were osteoporotic at either hip or spine, and this proportion rose to 41% if the ultradistal radius was included. Parathyroid hormone (PTH) was negatively correlated with BMD at all skeletal sites. In a multiple regression model, independent predictors of femoral neck BMD included body mass index (p=0.004), diabetes (p=0.025), and PTH (p=0.049). The only independent predictor of BMD at the ultradistal radius was PTH (p<0.001). Nineteen men sustained a total of 25 appendicular fractures after transplantation (median time to fracture was 3 years). Prevalent vertebral fractures were only identified in five men. PTH was elevated in 72.4% of patients (mean PTH 142 +/- 118 pg/ml). Bone resorption markers were increased in 48% of patients. PTH was positively correlated with serum carboxyterminal telopeptide of type 1 collagen (r=0.473, p<0.001) and procollagen type 1 amino terminal propeptide (r=0.419, p<0.001).

CONCLUSIONS

Osteopenia and osteoporosis are common in male transplant recipients, and the hip and radius are the most severely affected sites. Elevated rates of bone resorption driven by hyperparathyroidism appear to be the most important contributing factor.

Glucocorticoid-induced osteoporosis: from basic mechanisms to clinical aspects

Glucocorticoid (GC)-induced osteoporosis (GCOP) is the most common cause of osteoporosis in adults aged 20-45 years as well as the most common cause of iatrogenic osteoporosis. GC excess, either endogenous or exogenous, induces bone loss in 30-50% of cases. Indeed, bone loss leading to fractures is perhaps the most incapacitating, sometimes partially irreversible, complication of GC therapy. Nevertheless, GCOP is often underdiagnosed and left untreated. The following article provides an update on the cellular and molecular mechanisms implicated in the pathophysiology of GC-induced bone loss, as well as some guidelines on diagnostic, preventive and therapeutic strategies for this medical condition, in an effort to promote a better knowledge and greater awareness of GCOP by both the patient and the physician.

Liver transplantation-associated hypercalcemia followed by acute renal dysfunction

A 34-year-old woman with liver insufficiency due to glycogen storage disease III underwent a living spousal liver transplantation. Soon after the successful operation, moderate hypercalcemia along with hyperbilirubinemia emerged without clarified reasons. The hypercalcemia persisted for over a month despite calcitonin treatment and the serum calcium level surged to 13.2 mg/dl with albumin correction. Renal dysfunction was indicated by an acute increase in serum creatinine (approximately 0.8 to approximately 2.8 mg/ml), which was assumed to be hypercalcemia-induced and was effectively treated with bisphosphonate, pamidronate (30 mg, i.v.). Recent topics related to transplantation-associated hypercalcemia are discussed.

Osseous complications of pediatric transplantation

Adult stature and peak bone mass are achieved through childhood growth and development. Multiple factors impair this process in children undergoing solid organ transplantation, including chronic illness, pretransplant osteodystrophy, use of medications with negative impact on bone, and post-transplant renal dysfunction. While growth delay and short stature remain common, the most severe forms of transplant-related bone disease, fracture and avascular necrosis, appear to have become less common in the pediatric age group. Osteopenia is very prevalent in adult transplant recipients and probably also in pediatrics, but its occurrence and sequelae are difficult to study in these groups due to methodological shortfalls of planar densitometry related to short stature and altered patterns of growth and development. Although the effect on lifetime peak bone mass is not clear, data from adult populations suggest an elevated long-term risk of bone disease in children receiving transplants. Optimal management of pretransplantation osteodystrophy, attention to post-transplant renal insufficiency among both renal and non-renal transplant patients, reduction of steroid dose in select patients, and supplementation with calcium plus vitamin D during expected periods of maximal bone loss may improve bone health. Careful research is required to determine the role of bisphosphonate therapy in pediatric transplantation.

Alendronate versus calcitriol for the prevention of bone loss after cardiac transplantation

BACKGROUND

Osteoporosis is a well-known complication of cardiac transplantation. We conducted a randomized trial comparing alendronate with calcitriol for the prevention of bone loss during the first year after cardiac transplantation.

METHODS

A total of 149 patients were randomly assigned to receive either alendronate (10 mg per day) or calcitriol (0.5 microg per day) a mean (+/-SD) of 21+/-11 days after transplantation. Estimates of bone loss and the incidence of fractures among untreated patients were obtained from a reference group of 27 prospectively recruited patients who received cardiac transplants within the same period as the intervention groups.

RESULTS

At one year, the bone mineral density at the lumbar spine had decreased by a mean of 0.7 percent in the alendronate group and 1.6 percent in the calcitriol group (P=0.25 for the test of no difference). The bone mineral density at the femoral neck decreased by a mean of 1.7 percent in the alendronate group and 2.1 percent in the calcitriol group (P=0.69). In the reference group, the mean bone mineral density at the lumbar spine decreased by 3.2 percent (P=0.03 for the comparison with the alendronate group; P=0.15 for the comparison with the calcitriol group), and the mean density at the femoral neck decreased by 6.2 percent (P=0.001 for comparisons with both intervention groups). The incidence of vertebral fractures did not differ significantly among the groups (6.8 percent in the alendronate group, 3.6 percent in the calcitriol group, and 13.6 percent in the reference group). Hypercalciuria developed in 27 percent of the patients in the calcitriol group and 7 percent of those in the alendronate group (P=0.01).

CONCLUSIONS

The degree of bone loss and the rates of fracture did not differ significantly between the intervention groups. Calcitriol was associated with a higher risk of hypercalciuria. Alendronate-treated patients sustained less bone loss at the spine than those in the reference group, and both intervention groups sustained less bone loss at the hip than the reference group. The requirement for monitoring the serum and urinary calcium levels in calcitriol-treated patients makes alendronate more attractive for the prevention of bone loss early after cardiac transplantation.

Management of patients on chronic glucocorticoid therapy: an endocrine perspective

Glucocorticoids continue to be a potent therapeutic tool for various medical conditions; however, their medication side effects pose challenges. Steroid diabetes is treated primarily with prandial insulin, either regular or the rapid insulins (lispro or aspart). Intermediate insulin is indicated less frequently, for fasting hyperglycemia. Osteoporosis is the most debilitating of potential glucocorticoid side effects, with bisphosphonates the mainstay of prevention and treatment. Dyslipidemia can range from mild to significant, but it responds to therapy similar to that of nonglucocorticoid-induced lipid disorders. Glucocorticoid-induced adrenal withdrawal syndrome can occur even with short courses of longer-acting glucocorticoid therapy, but it responds to adjustment of glucocorticoid dose. When tapering down to near-physiologic dose, pituitary-adrenal axis responsiveness should be checked before discontinuing steroid use.

Bone mineral density and osteonecrosis in survivors of childhood allogeneic bone marrow transplantation

Our purpose was to evaluate frequency and severity of bone mineral decrements and frequency of osteonecrosis in survivors of pediatric allogeneic bone marrow transplantation (alloBMT). We retrospectively reviewed demographic information, treatment, magnetic resonance (MR) imaging studies (hips and knees), and bone mineral density (BMD) studies of 48 patients as measured by quantitative computed tomography (QCT). In all, 24 patients were male; 37 were Caucasian. Median age at alloBMT was 10.3 years (1.6-20.4 years). Of the 48 patients, 43 underwent QCT. Median time between alloBMT and imaging was 5.1 years (1.0-10.2 years). Median BMD Z-score was -0.89 (-4.06 to 3.05). BMD Z-score tended to be associated with female sex (P=0.0559) but not with age at BMT, race, primary diagnosis, time from alloBMT, T-cell depletion of graft, total-body irradiation, or acute/chronic graft-versus-host disease (GVHD). MR showed osteonecrosis in 19 of 43 (44%). We found no associations between osteonecrosis and sex, race, diagnosis, age at BMT, history of GVHD, time from BMT, or T-cell depletion. Seven patients (15%) had MR changes of osteonecrosis and BMD Z-scores of less than -1 s.d. We conclude that pediatric alloBMT survivors have decreased BMD and are at risk of osteonecrosis. They should be monitored to assure early intervention that may ameliorate adverse outcomes.

Disorders associated with acute rapid and severe bone loss

We describe a constellation of bone diseases characterized by the common feature of acute, rapid, and severe bone loss accompanied by dramatic fracture rates. These disorders are poorly recognized, resulting mainly from systemic diseases, frailty, immobilization, and immunosuppressive drugs, such as glucocorticoids and the calcineurin inhibitors. The opportunity to prevent or treat fractures is commonly missed because they are often not detected. Ideally, patients need to be identified early and preventative therapy initiated promptly to avoid the rapid bone loss and fractures. The most effective therapy at present seems to be the bisphosphonates, particularly when bone resorption is predominant. However, more severe forms of bone loss that result from an osteoblastic defect and reduced bone formation may benefit potentially more from newer anabolic agents, such as recombinant human parathyroid hormone (rhPTH).

Inhaled corticosteroids: past lessons and future issues

Inhaled corticosteroids play a pivotal role in the treatment of asthma. Inhalation permits effective delivery of the corticosteroid in high concentration to target sites within the lung while minimizing systemic exposure. Consequently, the safety profile of inhaled corticosteroids is markedly better than that of oral corticosteroid therapy. However, although it was first thought that direct delivery might eliminate systemic adverse effects, this has not been confirmed by clinical trials and experience. Inhaled corticosteroids are absorbed from the lungs into the systemic circulation, in which they can acutely decrease growth velocity in children, an effect that fortunately appears to be temporary and might have no effect on final adult height. In sufficient dosages, they also produce bone mineral loss leading to osteoporosis and might increase the risk of cataracts, glaucoma, skin atrophy, and vascular changes that increase the risk of ecchymoses. Effective evaluation of the severity and significance of these complications is challenging because highly sensitive tests do not reliably predict clinically significant events, and short-term observations do not predict long-term consequences. Also, compliance wanes with long-term treatment, and susceptibility to a particular adverse event can vary over time, even in the same individual, because of developmental or hormonal changes. This journal supplement will review what has been learned about the safety of inhaled cortico-steroids during the past decade, discussing some of the questions that remain and considering the characteristics of an "ideal" inhaled corticosteroid: one with high local activity in the lung and minimal or no adverse systemic effects.

Resistance exercise training and alendronate reverse Glucocorticoid-Induced osteoporosis in heart transplant recipients

BACKGROUND

Immunosuppression therapy with bolus glucocorticoids causes regional osteoporosis in the axial skeleton of heart transplant recipients (HTR). No preventive strategy is generally accepted for steroid-induced bone loss.

METHODS

To determine the efficacy of an anti-osteoporosis regimen that combined a bisphosphonate agent (alendronate sodium) with the osteogenic stimulus of mechanical loading, 25 HTRs were randomly assigned either to a group that received alendronate (10 mg/day) for 6 months (ALEN; n = 8), a group that received alendronate (10 mg/day) and performed specific resistance exercises for 6 months (ALEN + TRN; n = 8) or to a non-intervention control group (CONTR; n = 9). Alendronate was initiated at 2 months after transplantation. Bone mineral density (BMD) of the total body, femur neck and lumbar spine (L-2 and L-3) was measured by dual-energy X-ray absorptiometry before and 2, 5 and 8 months after transplantation. Resistance training consisted of lumbar extension exercise (MedX) performed 1 day/week and 8 variable resistance exercises (MedX) performed 2 days/week.

RESULTS

Pre-transplantation BMD values did not differ among the 3 groups. BMD of the total body, femur neck and lumbar vertebra were significantly decreased below baseline at 2 months after transplantation in CONTR (-2.6 +/- 0.9%, -5.1 +/- 1.8%, -12.5 +/- 4.2%, respectively), ALEN (-2.8 +/- 0.8%, -5.3 +/- 1.6%, -12.0 +/- 3.9%) and ALEN + TRN groups (-2.7 +/- 1.0%, -5.6 +/- 2.1%, -11.2 +/- 3.7%). CONTR had further significant losses of BMD after 3 and 6 months. ALEN had no further regional BMD losses after initiation of alendronate therapy. ALEN + TRN restored BMD of the whole body, femur neck and lumbar vertebra to within 0.9%, 2.1%, and 3.4% of pre-transplantation levels, respectively.

CONCLUSIONS

Resistance exercise plus alendronate was more efficacious than alendronate alone in restoring BMD in HTRs. Our results indicate that anti-osteoporosis therapy in this population should include both an anti-resorptive agent as well as an osteogenic stimulus, such as mechanical loading.