Protective effect of short-tem calcitriol or cyclical etidronate on bone loss after cardiac or lung transplantation

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

Osteoporosis following heart transplantation and immunosuppressive therapy

Heart transplantation (HT) remains the ultimate final therapy for patients with end-stage heart failure, who despite optimal medical and surgical treatments exhibit severe symptoms. To prevent rejection of the transplanted organ, HT patients require life-long immunosuppressive therapy. The goal of the immunosuppression is to minimise the risk of immune-mediated graft rejection, while avoiding clinical side-effects. Current immunosuppressive agents have yielded good survival outcome, however, complications of the immunosuppressive therapy, such as impaired bone strength and increased fracture risk, are common among HT patients rendering increased morbidity and mortality rates. The main aim of the present review was to summarise current knowledge on bone strength impairment after HT and concomitant immunosuppressive therapy.

CYP3A4 is a crosslink between vitamin D and calcineurin inhibitors in solid organ transplant recipients: implications for bone health

The use of calcineurin inhibitors (CNIs) and vitamin D deficiency may contribute to the pathogenesis of post-transplant bone disease. CNIs and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) are substrates of the drug-metabolizing enzyme CYP3A4. This review summarizes the indications for the use of activated vitamin D analogs in post-transplant care and the current knowledge on the impact of CNIs on bone. We searched for clinical evidence of the interaction between CNIs and 1,25(OH)₂D₃. We also provide an overview of the literature on the interplay between vitamin D metabolism and CYP3A4 in experimental and clinical settings and discuss its possible implications for solid organ transplant recipients. In conclusion, there is a body of evidence on the interplay between vitamin D and the drug-metabolizing enzyme CYP3A4, which may have therapeutic implications.

Managing complications following lung transplantation

Lung transplantation has become a proven therapeutic option for patients with end-stage lung disease, extending life and providing improved quality of life to those who otherwise would continue to be breathless and oxygen-dependent. Over the past 20 years, considerable experience has been gained in understanding the multitude of medical and surgical issues that impact upon patient survival. Today, clinicians have an armamentarium of tools to manage diverse problems such as primary graft dysfunction, acute and chronic allograft rejection, airway anastomotic issues, infectious complications, renal dysfunction, diabetes and osteoporosis, hematological and gastrointestinal problems, malignancy, and other unique issues that confront immunosuppressed solid organ transplant recipients.

Bone Loss after Heart Transplant: Effect of Alendronate, Etidronate, Calcitonin, and Calcium plus Vitamin D3

Objective

To compare the effects of calcitonin, etidronate, and alendronate in preventing bone loss during the first 2 years after heart transplant.

Methods

A total of 222 heart transplant recipients (mean [SD] age, 52.4 [10] years, 85% male) were evaluated. Patients with normal bone mineral density (reference group, n = 102) received 1000 mg/d calcium plus 800 IU/d vitamin D3. The rest were assigned to 200 IU/d of calcitonin (n = 42), 400 mg/d etidronate orally for 14 days quarterly (n = 33), or 10 mg/d alendronate (n = 45). All patients received calcium and vitamin D. Bone mineral density was assessed by dual-energy x-ray absorptiometry in the lumbar spine, the entire femur, and the femoral neck at baseline and 6, 12, and 24 months after transplant.

Results

At 2 years after transplant, bone mineral density in the lumbar spine had decreased in the reference group (−3.07%), calcitonin group (−0.93%), and etidronate group (−1.87%) but not in the alendronate group (+4.9%; P < .001). After 2 years, bone mineral density in the entire femur decreased in all groups (−3.2% in the reference group, −3.6% in the calcitonin group, −4.6% in the etidronate group, and −0.5% in the alendronate group) but bone loss was significantly lower in the alendronate group ( P < .001). Bone mineral density in the femoral neck also decreased in all groups. The incidence of vertebral fractures did not differ among groups. Adverse events were similar between groups.

Conclusions

Alendronate therapy in heart transplant recipients was associated with a significant increase in bone mineral density in the lumbar spine and less bone loss at the hip.

Vitamin D in organ transplantation

Vitamin D deficiency is prevalent among patients with end-stage organ failure awaiting transplant. Low serum 25-hydroxyvitamin D (25-OHD) levels in these patients may be related to many disease-specific factors, as well as decreased sunlight exposure and limited intake of foods containing vitamin D. Low serum 25-OHD levels are also extremely common following solid organ transplantation, both during the immediate postoperative period and in long-term graft recipients. Demographic and lifestyle factors are important in determining D status in transplant recipients. Worse vitamin D status is associated with poorer general health, lower albumin, and even decreased survival among these patients. Although several studies have demonstrated that active forms of vitamin D and its analogues prevent bone loss following transplantation, the data do not show consistent benefit. These therapies may have particular utility after renal transplantation. However, given the narrow therapeutic window with respect to hypercalcemia and hypercalciuria, and the demonstrated efficacy of bisphosphonates to prevent post-transplantation bone loss, we regard these agents as adjunctive rather than primary therapy for transplantation osteoporosis. The effects of 1,25(OH)(2)D on the immune system, which are still being elucidated, may have potential for reducing infections and preventing allograft rejection after transplantation.

Osteoporosis following organ transplantation: pathogenesis, diagnosis and management

Organ transplantation has become popular for the management of various chronic illnesses. With the advent of modern immunosuppressive treatments, the longevity of transplant recipients has increased. Consequently, morbid complications such as osteoporosis and bone fractures are seen at an increasing frequency in this population. In most transplant recipients, bone mineral density (BMD) falls shortly after transplantation. However, bone fracture rate plateaus in all except for post-renal transplant patients. Although the underlying pathophysiologic mechanism for this difference is not fully understood, potential mechanisms for sustained bone loss in renal transplant recipients may be persistent phosphorus wasting and defective bone mineralization. Current treatment regimens are based on studies in a small numbers of subjects with BMD as the primary outcome. Although BMD is recognized as a gold standard in the assessment of bone fracture risk, to date, its association with bone fracture risk in the general post-transplant population is not robust. Therefore, randomized controlled trials with bone fracture as the primary end point are crucial. The development of noninvasive bone markers in distinguishing bone turnover and bone mineralization status is also pivotal since skeletal lesions are heterogeneous in various organ transplantations. The elucidation of these underlying skeletal lesions is necessary for the consideration of selective treatment in this population.

Individualized therapy to prevent bone mineral density loss after kidney and kidney-pancreas transplantation

BACKGROUND AND OBJECTIVES

Most patients who undergo kidney or kidney-pancreas transplantation have renal osteodystrophy, and immediately after transplantation bone mineral density (BMD) commonly falls. Together, these abnormalities predispose to an increased fracture incidence. Bisphosphonate or calcitriol therapy can preserve BMD after transplantation, but although bisphosphonates may be more effective, they pose potential risks for adynamic bone.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 153 kidney (61%) and kidney-pancreas (39%) transplant recipients were allocated to bisphosphonate (62%) or calcitriol (38%) therapy using an algorithm that incorporated BMD, prevalent vertebral fracture, biomarkers of bone turnover, and risk factor assessment. Patients received cholecalciferol and calcium as appropriate and were followed for 12 mo.

RESULTS

Patients who were treated with bisphosphonates had lower BMD at the lumbar spine and femoral neck and longer time on dialysis. Age and gender were similar between the groups. At 12 mo, bisphosphonate-treated patients had significant BMD increases at the lumber spine and femoral neck and a negative trend at the wrist. Patients who were allocated to calcitriol, who were assessed to have lower baseline fracture risk, had no significant change in BMD at any site. At 1 yr, mean levels of bone turnover marker and intact parathyroid hormone normalized in both groups. Incident fracture rates did not differ significantly.

CONCLUSIONS

With targeted treatment, BMD levels were stable or improved and bone turnover markers normalized. This algorithm provides a guide to targeting therapy after transplantation that avoids BMD loss and may reduce suppression of bone turnover.

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

Transplantation is an established therapy for end-stage diseases of the kidney, endocrine pancreas, heart, liver, and lung, and for many hematologic disorders. Improved survival rates have been accompanied by increased recognition of previously neglected long-term complications of transplantation such as fractures and osteoporosis. Pretransplantation bone disease and immunosuppressive therapy result in rapid bone loss and increased fracture rates early after transplantation. Patients should be assessed and pretransplantation bone disease should be treated. Preventive therapy initiated in the immediate posttransplantation period is indicated in patients with osteopenia or osteoporosis, as further bone loss will occur in the first several months after transplantation. Long-term organ transplant recipients should also have bone mass measurement and treatment of osteoporosis. Bisphosphonates are the most promising approach for the management of transplantation osteoporosis. Active vitamin D metabolites may have additional benefits in reducing hyperparathyroidism, particularly after kidney transplantation. Large, multicenter treatment trials with oral or parenteral bisphosphonates and calcitriol are recommended.

Glucocorticoid-Induced Osteoporosis: Mechanisms and Therapeutic Approach

GCs constitute a therapeutic class largely used in clinical medicine for the curative or supportive treatment of various conditions involving the intervention of numerous medical specialties. Beyond their favorable therapeutic effects, GCs almost invariably provoke bone loss and a rapid increase in bone fragility, with its host of fractures. Men and postmenopausal women constitute a preferential target for the bone complications of GCs. The premenopausal status is not, however, a shelter; bone loss also happens in young women who are on GCs. Exposure to GCs yields a fracture risk exceeding the risk conferred by a low BMD per se. Therefore, some reason exists to settle the BMD threshold for therapeutic intervention not at -2.5 T-scores but at -1.0 or -1.5 T-scores, even if no prospective randomized trial so far endorses that opinion. Nowadays, bisphosphonate therapy should be proposed to every patient at risk for fragility fracture, along with calcium and vitamin D supplementation. Studies of other therapeutic modalities (eg, promoters of bone formation) are in progress.

Effects of tacrolimus, cyclosporin A and sirolimus on MG63 cells

The reduction in bone mineral density after organ transplantation results in increased morbidity (post-transplantation bone disease) and remains an unsolved problem. A connection with the long-term application of nonglucocorticoidal immunosuppressants is the subject of controversial discussion. We hypothesized that such substances have an influence on the skeletal system on the cellular level by modulating osteoblast differentiation. Therefore, we investigated the effects of tacrolimus, cyclosporin A and sirolimus as representative substances of nonglucocorticoidal immunosuppressants on cell proliferation and expression of bone tissue-specific genes of human osteoblasts (MG63). None of the examined substances affected cell proliferation, but all influenced the gene expression pattern towards change in cell differentiation. In detail, collagen III and XII, matrix metalloproteinase 2, SMAD2, epithelial growth factor receptor, annexin V and osteonectin expression were increased by all of the examined substances. Tacrolimus, cyclosporin A and sirolimus influence intracellular signalling pathways, transmembranous receptors and bone-specific matrix synthesis. They do not have antiproliferative or toxic effects. We postulate that the shown changes of osteoblast differentiation cause post-transplantation disease.

The Prevention of Bone Fractures After Liver Transplantation: Experience With Alendronate Treatment

OBJECTIVE

The aim of this study was to prevent fractures in the first postoperative year.

METHODS AND PATIENTS

We studied 59 patients (48 men, 11 women) aged 42.6+/-11.4 years, who underwent liver transplantation. All patients received oral alendronate 70 mg weekly and calcium 1 g and calcitriol 0.5 mug daily. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at the lumbar spine and proximal femur at baseline as well as at 6 and 12 months after transplantation for comparison with an historical control group (n=31). Spinal radiographs were obtained to assess vertebral fractures at the same time. Additionally, serum osteocalcin, serum parathyroid hormone (PTH), urinary deoxypyridinoline (DPD), and biochemical parameters were determined every 3 months.

RESULTS

At baseline, femoral total BMD of men was significantly greater than that of women (P<.05, .85+/-.1 vs .74+/-.1). A significant increase in BMD was observed at 12 months (P<.05), no patient developed a bone fracture. Comparison analysis of genders showed that there was a significant difference in favor of men (P<.05). The lumbar BMD, neck T-, and Z-scores were significantly higher among patients treated with alendronate than historical controls (P<.05). After 3 months, serum PTH was increased and serum osteocalcin and urinary DPD were reduced. No severe side effects from alendronate treatment were observed during the study.

CONCLUSION

A direct sign of the success of our study was no fracture observed during the first postoperative year. Alendronate should be considered for patients with low bone mass after liver transplantation.

Markers of bone metabolism in congestive heart failure

Congestive heart failure (CHF) is a chronic disease, whose incidence is especially growing in the subpopulation of elderly people. CHF is characterized by dyspnea and fatigue at rest or with exertion, ankle swelling and pulmonary edema. Cardiac transplantation is the ultimate therapeutic measure in patients with end-stage CHF. Some risk factors associated with CHF such as low mobility, renal failure, and prescription of specific drugs may predispose patients to develop osteoporosis. This review article gives an overview about markers of bone metabolism in CHF patients as well as in heart transplant recipients. At first, the physiology of bone metabolism is summarized. Then, a short description of different bone formation and resorption markers is presented. They can be used to characterize actual bone metabolism and can be helpful to explain possible mechanisms of bone loss. Regarding pre-transplant CHF patients, available data indicate that the disturbances in bone metabolism are only subtle. Heart transplant recipients, however, are at increased risk for osteoporotic bone loss due to the use of immunosuppressive agents such as corticosteroids and calcineurin inhibitors. Preventive strategies are able to normalize bone metabolism and to attenuate the high bone loss during the first year after heart transplantation.

Discontinuing Antiresorptive Therapy One Year after Cardiac Transplantation: Effect on Bone Density and Bone Turnover

BACKGROUND

We have previously reported that subjects randomized to alendronate or calcitriol immediately after cardiac transplantation sustained minimal bone loss during the first year, significantly less than a concurrently transplanted reference group that received calcium and parent vitamin D. In this extension, we evaluated the effect of discontinuing alendronate or calcitriol on bone loss and biochemical markers of bone turnover during the second year. We hypothesized that subjects who discontinued alendronate, which has a long half-life in bone, would not sustain significant bone loss. As the half-life of calcitriol is short, we hypothesized that there would be significant bone loss after discontinuing calcitriol.

METHODS

We measured bone density (BMD), calciotropic hormones and bone turnover markers at 12, 18, and 24 months after transplantation in adherent subjects who completed the randomized trial on alendronate or calcitriol, and in reference subjects who had received no preventive therapy.

RESULTS

In all, 75 subjects (34 alendronate, 25 calcitriol, 16 reference) participated. During the second year, the bone resorption marker, serum N-telopeptide, rose by 27% in the calcitriol group (P< or =0.001). Bone alkaline phosphatase, a bone formation marker, increased by 54% in the calcitriol group (P< or =0.001) and by 32% in the alendronate group (P< or =0.001). BMD did not change significantly at any site in either randomized group.

CONCLUSIONS

After discontinuing alendronate or calcitriol, BMD remained stable during the second year after cardiac transplantation, despite a significant increase in a biochemical marker of bone resorption in the calcitriol group. This suggests that antiresorptive therapy may be discontinued at the end of the first posttransplantation year in cardiac transplant recipients without resumption of rapid bone loss. However, as increased bone turnover may predict future bone loss and fractures, such patients warrant observation to ensure that BMD remains stable long-term.

Evidence-based guidelines for the prevention and treatment of glucocorticoid-induced osteoporosis: a consensus document of the Belgian Bone Club

Glucocorticoids (GCs) are frequently prescribed for various inflammatory and/or life-threatening conditions concerning many systems in the body. However, they can provoke many aftereffects, of which osteoporosis (OP) is one of the most crippling complications, with its host of fractures. The dramatic increase in bone fragility is mainly attributable to the GC-induced rapid bone loss in all skeletal compartments. We have reviewed the meta-analyses and randomized controlled studies reporting medical therapeutic interventions currently registered in Belgium for the management of GC-OP comparatively with a placebo. Based on this research, an expert meeting developed a consensus on the prevention and therapy of GC-OP. The pathophysiology of GC-OP is complex. Several factors, acting separately or synergistically, have been described. Their great number could help to understand the rapidity of bone loss and of bone fragility occurrence, indicating that a rapid therapeutic intervention should be implemented to avoid complications. All patients on GCs are threatened with OP, so the prevention and/or therapy of GC-OP should be considered not only for postmenopausal females, but also for osteopenic premenopausal females and for males put on a daily dose of at least 7.5 mg equivalent prednisolone that is expected to last at least 3 months. Non-pharmacological interventions, such as exercise and avoidance of tobacco and alcohol, should be recommended, even if their role is not definitely settled in GC-OP prevention. Supplemental calcium and vitamin D should be considered as the first-line therapy because of the decrease in intestinal calcium absorption provoked by GCs. They also could be considered either as isolated therapy in patients taking less than 7.5 mg prednisolone daily and/or for a predicted period shorter than 3 months or as adjuvant therapy to other more potent drugs. Hormone replacement therapy could be considered in young postmenopausal females on GC, such as in postmenopausal OP, or in men with low androgen levels. Calcitonin appears to have a protective effect on trabecular bone in GC-OP, just as in postmenopausal OP. There is an increasing body of evidence supporting the antifracture efficacy of bisphosphonates, notably alendronate and risedronate. Preventative and curative therapy of GC-OP should be maintained as long as the patient is on GC treatment and could be stopped after weaning from GC, because there is more than circumstantial evidence of some recovery of BMD when GCs are stopped. There is no indication in GC-OP for any combination of two antiresorptive agents (except for calcium and vitamin D) or for an antiresorptive and an anabolic agent. There is indeed no proof that the increased costs of combined treatments will translate into increased therapeutic efficacy.

Posttransplantation Bone Disease

Transplanted patients experience rapid loss of bone, high fracture rates, and increases in morbidity and mortality as a consequence of a posttransplant scenario that is highly deleterious to the skeleton. Immune suppressive drugs, especially glucocorticoids, are toxic to bone, often acting on a background of preexisting osteodystrophy resulting from long-standing renal, hepatic, cardiac, or pulmonary disease. Cyclosporin and tacrolimus lead to a severe osteopenic state in rats, but the skeletal toxicity of the calcineurin inhibitors in the clinical environment is less clear. Nor is it clear whether cyclosporin and tacrolimus differ in their skeletal actions. Mycophenolate mofetil and sirolimus do not appear to have important skeletal toxicity. Preventative strategies include minimizing glucocorticoid exposure and implementing therapies to counter the increase in bone resorption and decrease in bone formation that follows transplantation. Antiresorptive agents, especially bisphosphonates, appear capable of retarding or halting the early bone loss and possibly reduce fracture rates also. Vitamin D and calcium are ineffective, but calcitriol has utility in some reports. Bone anabolic agents, such as synthetic parathyroid hormone and growth hormone, have potential, but data are lacking.

Pancreas transplantation: indications and consequences

Pancreas transplantation continues to evolve as a strategy in the management of diabetes mellitus. The first combined pancreas-kidney transplant was reported in 1967, but pancreas transplant now represents a number of procedures, each with different indications, risks, benefits, and outcomes. This review will summarize these procedures, including their risks and outcomes in comparison to kidney transplantation alone, and how or if they affect the consequences of diabetes: hyperglycemia, hypoglycemia, and microvascular and macrovascular complications. In addition, the new risks introduced by immunosuppression will be reviewed, including infections, cancer, osteoporosis, reproductive function, and the impact of immunosuppression medications on blood pressure, lipids, and glucose tolerance. It is imperative that an endocrinologist remain involved in the care of the pancreas transplant recipient, even when glucose is normal, because of the myriad of issues encountered post transplant, including ongoing management of diabetic complications, prevention of bone loss, and screening for failure of the pancreas graft with reinstitution of treatment when indicated. Although long-term patient and graft survival have improved greatly after pancreas transplant, a multidisciplinary team is needed to maximize long-term quality, as well as quantity, of life for the pancreas transplant recipient.

Management of bone loss after organ transplantation

Organ transplant recipients experience rapid bone loss and high fracture rates, particularly during the early post-transplant period. Early rapid bone loss occurs in the setting of uncoupled bone turnover with increased bone resorption and decreased bone formation. Because there are no clinical factors that reliably predict post-transplant bone loss and fractures in the individual patient, all transplant recipients should be considered candidates for early preventive therapy for osteoporosis. Long-term transplant recipients with densitometric osteoporosis and/or fractures should also receive treatment. Although active metabolites of vitamin D and bisphosphonates have both shown efficacy, data from clinical trials suggest that bisphosphonates are the safest and most consistently effective agents for the prevention and treatment of post-transplantation osteoporosis in adults. Kidney transplant recipients represent a special population, and more research is needed to delineate the risks and benefits of treating bone disease in these patients.

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.

Prevention and treatment of glucocorticoid-induced osteoporosis with active vitamin D3 analogues: a review with meta-analysis of randomized controlled trials including organ transplantation studies

The aim of this review with meta-analysis was to determine if there is a rationale to use activated forms of vitamin D3 to treat or prevent glucocorticoid-induced osteoporosis, and to compare the effect of active vitamin D3 metabolites with that of other anti-osteoporosis therapies. We performed a systemic search using MEDLINE/PubMed (1966-2003). Animal studies and clinical trials involving humans with data on therapy to treat or prevent glucocorticoid-induced osteoporosis with active vitamin D3 analogues were included. Animal studies and basic research studies with active vitamin D3 were reviewed (qualitative review). Meta-analysis (quantitative review) on clinical trials (including organ transplantation studies) was performed with percent change in lumbar spine bone mineral density or bone mineral content as the primary outcome measure; the secondary outcome measure was incidence of vertebral fractures. Fifty-four articles were found. Animal and basic research studies showed that active vitamin D3 analogues can inhibit bone loss during treatment with glucocorticoids. Concerning the effect on bone mineral density, the pooled effect size of active vitamin D3 analogues compared with no treatment, placebo, plain vitamin D3 and/or calcium was 0.35 (95% confidence interval (CI) 0.18, 0.52). Compared with bisphosphonates, the pooled effect size was -1.03 (95% CI -1.71, -0.36). The pooled estimate of the relative risk for vertebral fractures of active vitamin D3 analogues compared with no treatment, placebo, plain vitamin D3 and/or calcium was 0.56 (95% CI 0.34, 0.92) and compared with bisphosphonates it was 1.20 (95% CI 0.32, 4.55). Active vitamin D3 analogues not only preserve bone during glucocorticoid therapy more effectively than no treatment, placebo, plain vitamin D3 and/or calcium, but are also more effective in decreasing the risk of vertebral fractures. Bisphosphonates, however, are more effective in preserving bone and decreasing the risk of vertebral fractures than active vitamin D3 analogues.

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.

Down-regulation by nuclear factor kappaB of human 25-hydroxyvitamin D3 1alpha-hydroxylase promoter

1,25-(OH)(2) vitamin D(3) is important for calcium homeostasis and cell differentiation. The key enzyme for the activation of liver-derived 25(OH) vitamin D(3) is 25-hydroxyvitamin D(3) 1alpha-hydroxylase. It is expressed mainly in the kidney but also in peripheral tissues. A 1413-bp fragment of the 1alpha-hydroxylase promoter was cloned into luciferase vectors pGL2basic and pGL3basic. Sequence analyses revealed four base exchanges and three base deletions compared with the published sequence which were identically found in five control persons. In silico promoter analyses revealed 17 putative nuclear factor (NF)kappaB sites, 10 of which were found to bind NFkappaB in EMSA experiments. Cotransfection of NFkappaB p50 and p65 subunits resulted in dramatic reduction of the promoter activity of the full-length construct as well as a series of 5'-deletion constructs. Deletion of the farmost 3'-situated NFkappaB-responsive element almost abolished NFkappaB responsiveness. Treatment of human embryonic kidney 293 cells with sulfasalazine, a NFkappaB inhibitor, resulted in enhanced 1alpha-hydroxylase mRNA production. Down-regulation of 1alpha-hydroxylase promoter through NFkappaB signaling may contribute to the pathogenesis of inflammation-associated osteopenia/osteoporosis.

Osteoporosis: The dynamic relationship between magnesium and bone mineral density in the heart transplant patient

Osteoporosis is a common, and potentially severe, complication seen in the heart transplant recipient. Frequently there is loss of bone mineral density prior to transplant that begins the downward spiral to fractures of the femoral neck and vertebrae. Multiple factors are responsible for the development of osteoporosis posttransplant. These factors include pretransplant bone mineral loss, use of corticosteroids and cyclosporine posttransplant, and development of persistent hypomagnesemia posttransplant. This article explores the relationship of serum magnesium levels to maintenance of bone mineral density.

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.

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).

Recipient selection

Since international recommendations for lung transplant recipients were made in 1998, newer tools for predicting mortality in patients who have end-stage lung disease have been investigated. This article reviews studies for predicting mortality in obstructive, restrictive, pulmonary vascular, and suppurative/bronchiectatic lung disease. Newer considerations for alternative treatments, postoperative risks, and contraindications are also examined. The article aims to provide more accurate data for selecting patients who will benefit from lung transplantation.

Reduction of immunosuppressant therapy requirement in heart transplantation by calcitriol

Calcitriol has been shown to have immunomodulatory effects. We examined whether heart transplant recipients, randomly assigned to receive calcitriol to reduce bone loss, required less immunosuppressive therapy or demonstrated different rejection and survival outcomes. Patients receiving low-dose calcitriol required substantially lower cumulative doses of cyclosporin (29% [95% confidence interval; 8%-50%] and 28% [7%-50%] for 1 and 2 years, respectively) for organ rejection without any detectable change in episodes of rejection, infection, or deaths. This major reduction of oral cyclosporine requirement, in addition to the skeletal benefits of calcitriol in those receiving immunosuppressive therapy, indicates a potential role for co-therapy with calcitriol or its analogues in the management of patients with solid-organ transplantation.

Prevention and treatment of glucocorticoid-induced osteoporosis: a comparison of calcitriol, vitamin D plus calcium, and alendronate plus calcium

High-dose corticosteroids, used for many medical conditions, are associated with rapid bone loss from sites such as the vertebrae, and compression fractures can be observed within months. Recent trials suggest treatment with bisphosphonates or active vitamin D analogs can reduce bone loss and the risk of fracture associated with glucocorticoids, but few studies have directly compared such agents. We conducted a randomized, multicenter, open-label trial to compare the efficacy of alendronate, calcitriol, and simple vitamin D in prevention and treatment of glucocorticoid-induced bone loss. A total of 195 subjects (134 females and 61 males) commencing or already taking glucocorticoids were randomized to one of three groups: calcitriol, 0.5 to 0.75 microg/day; simple vitamin D (ergocalciferol, 30,000 IU weekly) plus calcium carbonate (600 mg daily); or alendronate, 10 mg/day plus calcium carbonate (600 mg daily). Over 2 years, mean lumbar bone mineral density change was +5.9% with alendronate, -0.5% with ergocalciferol, and -0.7% with calcitriol (p < 0.001). At the femoral neck, there was no significant difference in bone mineral density change between the treatments over 2 years: alendronate (+0.9%), ergocalciferol (-3.2%), and calcitriol (-2.2%). Lumbar bone loss varied according to whether patients were starting or receiving chronic glucocorticoids, and there was a significant treatment x prior glucocorticoid use interaction effect. Six of 66 calcitriol subjects, 1 of 61 ergocalciferol subjects, and 0 of 64 alendronate subjects sustained new vertebral fractures. These data do not suggest any difference between simple vitamin D and calcitriol but do show that alendronate was superior to either treatment for glucocorticoid induced bone loss.

Pancreas and kidney transplantation

Kidney transplantation is preferred over dialysis for management of end-stage renal disease complicating type I or type 2 diabetes, for those who are eligible. Simultaneous pancreas-kidney (SPK) or pancreas after kidney transplantation (PAK) is an important alternative to kidney transplantation alone for type I diabetes patients if the patient is able to withstand the additional risks of these procedures, because of the benefits of glucose control on other diabetic complications. Pancreas transplantation alone (PTA) is most useful for the treatment of debilitating, frequent hypoglycemia complicating type I diabetes, if renal function is adequate. One-year pancreas graft survival is best after SPK (82%) but has significantly improved after both PAK (74%) and PTA (76%). The I-year kidney graft and patient survival rates after SPK are similar to kidney transplantation alone. Pancreas transplantation normalizes glucose beyond what can be achieved with insulin therapy and has been shown to decrease progression of or improve most, if not all, diabetic end-organ complications using current immunosuppression regimens. However, the diabetologist and endocrinologist should remain involved in the care of the pancreas or kidney transplant recipient for treatment of vascular disease risk factors such as dyslipidemia, surveillance of other diabetic complications including foot ulcers, surveillance and treatment of bone loss, and management of hyperglycemia if it recurs.

The comparative efficacy of drug therapies used for the management of corticosteroid-induced osteoporosis: a meta-regression

We determined the comparative efficacy of vitamin D, calcitonin, fluoride, and bisphosphonates for the management of corticosteroid-induced osteoporosis using meta-regression models. A systematic search for trials was conducted using MEDLINE, bibliographic references, abstracts from national meetings, and contact with pharmaceutical companies and content experts. We included all randomized controlled trials, lasting at least 6 months, of adult patients on oral corticosteroids that evaluated treatment comparisons between vitamin D, calcitonin, bisphosphonates, or fluoride either with no therapy/calcium or with each other and that reported extractable results. The outcome measure of interest was change in lumbar spine bone mineral density (BMD). We identified 45 eligible trials, which provided 49 eligible treatment comparisons (some trials had three arms or more). Our results indicated that bisphosphonates were the most effective class (effect size 1.03; 95% CI: 0.85, 1.17); results were similar even when newer generations of nitrogen-containing bisphosphonates were excluded from analysis. We found the efficacy of bisphosphonates was enhanced further when used in combination with vitamin D (effect size, 1.31; 95% CI: 1.07, 1.50). Vitamin D and calcitonin were more effective than no therapy/calcium (effect size, 0.46; 95% CI: 0.27, 0.62; and effect size, 0.51; 95% CI: 0.33, 0.67, respectively) and were of similar efficacy, but both were significantly less effective than bisphosphonates. Fluoride appeared effective, but there were too few studies (n = 5) to draw robust conclusions regarding its efficacy compared with the other three therapies. In summary, bisphosphonates are the most effective of evaluated agents for managing corticosteroid-induced osteoporosis. The efficacy of bisphosphonates is enhanced further with concomitant use of vitamin D.

Treatment with vitamin D and calcium reduces bone loss after renal transplantation: a randomized study

A decrease in bone mineral density (BMD) is a major complication of renal transplantation (RTx), predominantly occurring within the first 6 mo after RTx. The most important causative factor is the use of corticosteroids, but persisting hyperparathyroidism and abnormalities in vitamin D metabolism play a role too. This study examines the effect of treatment with calcium and active vitamin D on the loss of BMD in the first 6 mo after RTx. A total of 111 renal transplant recipients (65 men, 46 women; age, 47 +/- 13 yr) were randomized to either treatment with active vitamin D (0.25 microg/d) plus calcium (1000 mg/d) (CaD group), or to no treatment (NoT group). Immunosuppressive therapy consisted of cyclosporine, prednisone, and mycophenolate mofetil. Laboratory parameters and BMD (lumbar spine and hip) were measured at 0, 1 (laboratory only), 3, and 6 mo after RTx. Lumbar BMD was nearly normal at the time of RTx. In both groups, a significant decrease in lumbar BMD was observed during the first 3 mo (CaD, -3.3 +/- 4.3%; P < 0.0001; NoT, -4.1 +/- 4.8%; P < 0.0001). Between the third day and sixth month, lumbar BMD slightly recovered in the CaD group, but it decreased further in the NoT group (total loss 0 to 6 mo: CaD, -2.6 +/- 5.0% [P < 0.001]; NoT, -5.0 +/- 4.7% [P < 0.0001]). As a result, the amount of bone loss at 6 mo was significantly lower in the CaD group (P = 0.02). Loss of BMD at the different femoral sites was also significantly reduced in the CaD group. Apart from a trend toward more frequent hypercalcemia in the CaD group, no clinical or biochemical differences existed between the groups. Treatment with a low dose of active vitamin D and calcium partially prevents bone loss at the lumbar spine and proximal femur during the first 6 mo after RTx.

Secondary causes of osteoporosis

Secondary causes of bone loss are not often considered in patients who are diagnosed as having osteoporosis. In some studies, 20% to 30% of postmenopausal women and more than 50% of men with osteoporosis have a secondary cause. There are numerous causes of secondary bone loss, including adverse effects of drug therapy, endocrine disorders, eating disorders, immobilization, marrow-related disorders, disorders of the gastrointestinal or biliary tract, renal disease, and cancer. Patients who have undergone organ transplantation are also at increased risk for osteoporosis. In many cases, the adverse effects of osteoporosis are reversible with appropriate intervention. Because of the many treatment options that are now available for patients with osteoporosis and the tremendous advances that have been made in understanding the pathogenesis and diagnosis of the condition, it is important that medical disorders are recognized and appropriate interventions are undertaken. This article provides the framework for understanding causes of bone loss and approaches to their management.

Prevention of osteoporosis in cardiac transplant recipients

Osteoporosis is a leading cause of pretransplant and posttransplant morbidity. The need for early detection by measuring bone mineral density, even before transplant, must be emphasized. Preventive measures are not comparable. The use of calcium and vitamin D supplements, although recommended, is inadequate for the prevention of bone loss and complications such as vertebral fractures. Bisphosphonates have been shown to attenuate the bone loss and reduce fractures associated with steroid-induced osteoporosis. Small studies in transplant recipients suggest similar results. Other preventive measures such as hormone replacement therapy are also helpful. There are limited data on the administration of nasal calcitonin in transplant recipients.