High prevalence of osteoporosis in cardiac transplant recipients and discordance between biochemical turnover markers and bone histomorphometry

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.

Factors associated with degraded trabecular bone score in heart transplant recipients

Trabecular bone score (TBS) is a textural index that provides indirect evaluation of trabecular microarchitecture. It improves fracture risk assessment in several high-risk populations. We aimed to evaluate the role of TBS assessment in heart transplant recipients (HTR). In a cross-sectional study with 87 HTR (69 males and 18 females), we assessed TBS and evaluated potential associations between TBS and factors related to increased fracture risk. We also evaluated the correlations between the presence of vertebral fractures (VF) and degraded TBS. We confirmed degraded TBS in the majority of HTR. 27.6% of HTR had partially degraded, 27.6% had degraded TBS. HTR with degraded TBS were older, had higher body mass index, lower bone mineral density (BMD), and T-score. As opposed to stable BMD over different time points, TBS significantly differed among different post-transplant time periods. TBS did not correlate with current methylprednisolone or past zoledronic acid treatment, presence of hypogonadism or diabetes. TBS did not have additional value over BMD in predicting the presence of VF. Most fractures occurred in patients with osteopenia and in patients with partly degraded TBS. Studies with longitudinal designs and larger sample sizes are warranted to further assess the potential role of TBS in HRT.

Endocrine disorders after heart transplantation: national cohort study

BACKGROUND

Endocrine disorders in patients after heart transplantation (HT) remain understudied. We aimed to assess endocrine profiles and management of HT recipients in the early post- transplant period.

METHODS

We conducted a retrospective cohort study on 123 consecutive HT recipients in the Advanced Heart Failure and Transplantation Programme between 2009 and 2018. All recipients had per-protocol endocrine follow-up within the first postoperative year. The median time to first post-transplant endocrine follow-up was 3 months (IQR 2-4). We assessed the incidence of vitamin D deficiency, bone mineral density, history of low energy fractures, hypogonadism in male recipients, posttransplant diabetes mellitus, and thyroid and parathyroid function.

RESULTS

We enrolled 22 women and 101 men of median age 57 years (IQR 50-63). Post-transplant diabetes mellitus developed in 14 patients (11.4%). 18 of 25 patients (14.6%) with preexisting type 2 diabetes mellitus required intensification of antidiabetic therapy. 38 male patients (40.4%) had hypogonadism. 5 patients (4.6%) were hypothyroid and 10 (9.3%) latent hyperthyroid. Secondary hyperparathyroidism was present in 19 (17.3%), 25-hydroxyvitamin D deficiency in 64 (54.7%) of patients. Osteoporosis was present in 26 (21.1%), osteopenia in 59 (48.0%) patients. 47 vertebral fractures, 3 hip and 1 humerus fractures occurred in 21 patients. Most of the patients had coincidence of two or three disorders, while less than 5% did not have any endocrine irregularities. All patients received calcium and vitamin D supplements. Forty-six patients (37.4%) were treated with zoledronic acid, 12 (9.8%) with oral bisphosphonates. Two patients were treated with teriparatide.

CONCLUSIONS

The prevalence of multiple endocrine disorders early after heart transplantation is high. Assessment and management of increased fracture risk and all other potentially affected endocrine axes should be considered as a standard of care in this early period.

Bone in heart failure

There is an increasing interest in osteoporosis and reduced bone mineral density affecting not only post-menopausal women but also men, particularly with coexisting chronic diseases. Bone status in patients with stable chronic heart failure (HF) has been rarely studied so far. HF and osteoporosis are highly prevalent aging-related syndromes that exact a huge impact on society. Both disorders are common causes of loss of function and independence, and of prolonged hospitalizations, presenting a heavy burden on the health care system. The most devastating complication of osteoporosis is hip fracture, which is associated with high mortality risk and among those who survive, leads to a loss of function and independence often necessitating admission to long-term care. Current HF guidelines do not suggest screening methods or patient education in terms of osteoporosis or osteoporotic fracture. This review may serve as a solid base to discuss the need for bone health evaluation in HF patients.

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.

Bone density in heart or lung transplant recipients--a longitudinal study

BACKGROUND

Osteoporosis is prevalent among heart or lung transplant (HLT) candidates. Bone loss is common posttransplant, with an associated increase in fracture risk. There is a lack of consensus regarding optimal management of bone health in HLT recipients. We report bone health data in a cohort of HLT recipients before and after transplantation and make recommendations for management.

METHODS

Patients over the age of 20 who had a heart or lung transplant between 2000 and 2011 were identified from the New Zealand HLT Service database, and demographic data, immunosuppressive regimens, bisphosphonate use, and serial bone mineral density (BMD) data were extracted.

RESULTS

Pretransplant BMD was available in 52 heart and 72 lung transplant recipients; 30 and 42, respectively, also had posttransplant BMD data. Pretransplant osteopenia or osteoporosis prevalence were 23% and 8% for heart candidates and 36% and 31% for lung candidates. Posttransplant, BMD decreased significantly at the femoral neck but not at the lumbar spine in the first year, with subsequent stabilization particularly in the presence of bisphosphonate use. Pretransplant BMD was the major predictor for developing osteopenia or osteoporosis after transplantation.

CONCLUSION

A significant proportion of HLT recipients have osteopenia or osteoporosis pretransplant, and this persists posttransplant. Pretransplant BMD is an important predictor of subsequent osteopenia or osteoporosis development, allowing risk stratification and targeted intervention.

Congestive heart failure: where homeostasis begets dyshomeostasis

Despite today's standard of care, aimed at preventing homeostatic neurohormonal activation, one in every five patients recently hospitalized with congestive heart failure (CHF) will be readmitted within 30 days of discharge because of a recurrence of their symptoms and signs. In light of recent pathophysiological insights, it is now propitious to revisit CHF with a view toward complementary and evolving management strategies. CHF is a progressive systemic illness. Its features include: oxidative stress in diverse tissues; an immunostimulatory state with circulating proinflammatory cytokines; a wasting of soft tissues; and a resorption of bone. Its origins are rooted in homeostatic mechanisms gone awry to beget dyshomeostasis. For example, marked excretory losses of Ca2+ and Mg2+ accompany renin-angiotensin-aldosterone system activation, causing ionized hypocalcemia and hypomagnesemia that lead to secondary hyperparathyroidism with consequent bone resorption and a propensity to atraumatic fractures. Parathyroid hormone accounts for paradoxical intracellular Ca2+ overloading in diverse tissues and consequent systemic induction of oxidative stress. In cardiac myocytes and mitochondria, these events orchestrate opening of the mitochondrial permeability transition pore with an ensuing osmotic-based destruction of these organelles and resultant cardiomyocyte necrosis with myocardial scarring. Contemporaneous with Ca2+ and Mg2+ dyshomeostasis is hypozincemia and hyposelenemia, which compromise metalloenzyme-based antioxidant defenses, whereas hypovitaminosis D threatens Ca2+ stores needed to prevent secondary hyperparathyroidism. An intrinsically coupled dyshomeostasis of intracellular Ca2+ and Zn2+, representing pro-oxidant and antioxidant, respectively, is integral to regulating the mitochondrial redox state; it can be uncoupled by a Zn2+ supplement in favor of antioxidant defenses. Hence, the complementary use of nutriceuticals to nullify dyshomeostatic responses involving macro- and micronutrients should be considered. Evolving strategies with mitochondria-targeted interventions interfering with their uptake of Ca2+ or serving as selective antioxidant or mitochondrial permeability transition pore inhibitor may also prove efficacious in the overall management of CHF.

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.

Bone mineral status and bone loss over time in men with chronic systolic heart failure and their clinical and hormonal determinants

AIMS

Bone status has not been comprehensively studied in chronic heart failure (CHF). In CHF men, we evaluated bone status, bone loss over time, and their clinical and hormonal determinants.

METHODS AND RESULTS

Bone mineral content (BMC) and bone mineral density (BMD) of arms, legs, trunk, and total body were examined using dual-energy X-ray absorptiometry in 187 men with CHF [age: 60+/-11 years, left ventricular ejection fraction (LVEF): 32+/-7%, New York Heart Association (NYHA) class (I/II/III/IV): 20/76/76/15] and in 21 age-matched male controls without CHF. Men with CHF had reduced BMD and BMC compared with controls (P < 0.05). Reduced BMD and BMC were independently determined by CHF severity (high NYHA class and impaired LVEF), reduced lean tissue mass, low serum dehydroepiandrosterone sulphate, total testosterone (TT), and estimated free testosterone (eFT) (all P < 0.05). Bone status was reassessed in 60 patients who survived >2 years from the initial evaluation. Significant bone loss over time (a reduction in BMC total > or = 1%/year) occurred in 35% of CHF men. Advanced NYHA class (P < 0.05) and reduced serum TT and eFT (P < 0.0001) at baseline predicted augmented bone loss.

CONCLUSION

In CHF men, reduced BMD and BMC constitute an element of generalized body wasting, determined mainly by advanced heart failure and androgen deficiencies. Significant bone loss over time frequently occurs in CHF men and is related to testosterone depletion and disease severity.

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.

The effect of functional performance, respiratory function and osteopenia on the quality of life after heart transplantation

To determine the effect of functional performance, respiratory function, and osteopenia on the quality of life after heart transplantation. Thirty-one patients were included. Functional performance (peak oxygen consumption - pVO2), respiratory function, quality of life (the short form 36 - SF36) and lumbar spine and hip bone mineral density (BMD) were performed. There was a significant relationship between pVO2 and physical function and the physical role scores on the SF36 (p<0.05). Additionally, a significant relationship was found between the scores on the respiratory function tests and the physical and social function scores on the SF36 (p<0.05). There was no significant relationship found between osteopenia and SF36 scores (p>0.05).

Pediatric cardiac transplantation

Pediatric heart transplantation has undergone major changes over the past two decades, marked by a substantial improvement in survival, reduction in posttransplant complications, and enhancement in quality of life for transplant recipients. Actuarial survival has improved substantially in the last decade. Indications for pediatric heart transplant have changed as surgery for complex congenital heart lesions has evolved. There are now left and right ventricular assist devices that are suitable for use in infants as a bridge to transplantation. New immunosuppressive agents have reduced the risk of rejection while minimizing side effects and strategies to reduce the risk of graft coronary disease are beginning to show promise. Finally, true long-term survival for children after heart transplant has now been demonstrated and quality of life is excellent.

Physiological genomics of cardiac disease: quantitative relationships between gene expression and left ventricular hypertrophy

The pathogenesis of cardiac left ventricular hypertrophy and failure is poorly defined due to the complexity of the disease phenotype. To gain a better understanding of the relationship between gene expression and left ventricular hypertrophy, we employed a quantitative approach to identify genes with expression patterns that correlate in a numerically continuous manner with parameters of cardiac structure and function in a mouse model of left ventricular hypertrophy due to transverse aortic constriction. Several genes showed expression patterns that were significantly correlated (Pearson's correlation coefficient) with measurements of left ventricular weight, left ventricular wall thickness, and diastolic dimension. We validated our findings in two independent data sets and in a small subset of genes by real-time RT-PCR. Of genes with significant correlations to numerically continuous measurements of hypertrophy, we found enrichment for genes encoding extracellular matrix, growth-related and secreted proteins in the directly correlated subset, and for genes encoding mitochondria and metabolic/fatty acid oxidation proteins in the inversely correlated subset. The results of this filtering strategy suggest that this subset of transcripts with quantitative relationships between gene expression and left ventricular hypertrophy represents potentially important pathways that contribute to the progression to heart failure and are thus candidates for follow-up and functional analysis.

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.

Urinary NTX results rarely alter the clinical management of patients with osteoporosis in the tertiary hospital

AIM

Urinary levels of cross-linked N-terminal telopeptide of type I collagen (NTX) are used as a marker of bone resorption and are useful for monitoring response of patients treated with anti-resorptive agents. We aimed to determine how urinary NTX results alter clinical decision making by physicians treating patients with osteoporosis in a tertiary hospital setting.

METHODS

We reviewed patient notes of all new NTX requests in 2002 and 2003 with at least one subsequent repeat measurement. Patients with a diagnosis of osteoporosis and both pre- and post-treatment measurements of bone mineral density (BMD) and NTX were included. Urinary NTX was measured with the Osteomark enzyme-linked immunosorbent assay. BMD of the hip and lumbar spine was measured using dual energy X-ray absorptiometry (DEXA).

RESULTS

A total of 357 patients had serial NTX requests during the time period. Sixty-five of these patients had a diagnosis of osteoporosis. Out of 37 patients treated for osteoporosis who had complete data available, 29 patients had concordant results between BMD and NTX and eight patients had discordant results. Only one patient had treatment changed as a result of a lack of reduction in NTX following treatment. Thirteen patients had therapy altered. Common reasons for altering therapy were patient non-compliance, side effects and failure of BMD to increase.

CONCLUSIONS

Alteration to therapy in this patient population is mainly dictated by issues such as patient compliance, medication side effects and bone mineral density results rather than urinary NTX values.

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.

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.

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).

Pathogenesis of bone loss in heart transplant candidates and recipients

BACKGROUND

Heart transplantation (HTX) is associated with decreased bone mineral density and changes in bone metabolism. We conducted this study to evaluate the pathophysiology of bone metabolism in HTX candidates and recipients.

METHODS

Thirty-six HTX recipients were compared with 36 HTX candidates concerning biochemical parameters of bone metabolism and bone mineral density.

RESULTS

Osteocalcin, bone-specific alkaline phosphatase, cross-linked-N-telopeptide of type I collagen, estradiol, serum creatinine, and blood urea nitrogen concentrations were significantly higher, whereas the calcium-creatinine ratio, thyrotropin, thyroxine, and bone mineral density were significantly lower in HTX recipients than in HTX candidates. Compared with a control group, HTX candidates had decreased renal function and increased bone resorption, whereas HTX recipients additionally had increased alkaline phosphatase and osteocalcin levels. In HTX recipients, we found positive correlations between creatinine clearance and bone mineral density; daily and cumulative cortisone doses were not associated with bone mineral density.

CONCLUSIONS

In HTX candidates, disturbances in bone metabolism with increased bone resorption may be caused partly by existing low-grade renal insufficiency, regular intake of loop diuretics, and restriction of mobility. In HTX recipients, immunosuppressive therapy-glucocorticoids and cyclosporine-seem to be responsible for changes in bone metabolism.

Serum osteoprotegerin is a major determinant of bone density development and prevalent vertebral fracture status following cardiac transplantation

Osteoprotegerin (OPG) is an antiresorptive cytokine and a key regulator of osteoclastogenesis and activity. Since OPG is downregulated by glucocorticoids and cyclosporine A in vitro we examined whether immunosuppressive therapy would play a role in the development of transplantation osteoporosis. We enrolled 57 cardiac transplant recipients (median time since transplantation, 3.2 years (1.1-11.5 years)) in this cross-sectional study. Standardized spinal X-rays as well as hip bone density measurements were performed in all patients. Serum OPG was determined using a commercially available ELISA. Vertebral fractures were present in 56% of the patients. Bone densities of all femoral neck subregions were correlated to serum OPG concentrations (r values between 0.40 and 0.48, all P < 0.005). Multiple regression analysis revealed OPG levels to be independently correlated to femoral neck Z scores (r = 0.49, P = 0.002). After adjustment for age, BMI, neck Z score, renal function, and months since transplantation, serum OPG was the only significant predictor of prevalent vertebral fractures (P = 0.001). In a separate 6-month prospective study of 14 heart transplant recipients receiving calcium and vitamin D serum OPG levels fell by 41% (P = 0.0004) after 3 months and 47% (P = 0.0001) after 6 months following cardiac transplantation. Bone loss at the lumbar spine and femoral neck after 6 months was correlated to the decrease in serum OPG at 6 months (r = 0.82, P < 0.0001, and r = 0.60, P = 0.02, respectively) as well as 3 months after cardiac transplantation (r = 0.65, P = 0.01, and r = 0.69, P = 0.006, respectively). Serum OPG alone accounted for 67% of the variance of lumbar spine bone density changes over the first 6 months posttransplantation. We conclude that serum OPG levels decline consistently in all patients following initiation of immunosuppressive therapy and are independently correlated with changes in bone density. We hypothesize that OPG plays a major role in the development of transplantation osteoporosis.

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.

Loss of bone mass and vitamin D deficiency after hematopoietic stem cell transplantation: standard prophylactic measures fail to prevent osteoporosis

Bone mineral density (BMD) and biochemical markers of bone metabolism were analyzed in 67 adults with ALL (n = 27), AML (n = 14), MDS (n = 6) and CML (n = 20) before and after allogeneic stem cell transplantation (SCT). Median age was 36 years (17-56). Twenty-six out of 53 patients (49%) had osteopenia and osteoporosis before SCT, 21/26 had acute leukemias and 5/26 had chronic myeloid leukemia (CML). T-score before SCTwas -1.23 in patients with acute leukemias and 0.62 in CML patients (P = 0.001). After SCT, a significant loss of BMD was observed in all patients. After 6 months, 24 of 36 evaluable patients (67%) had pathologic BMD, 11 of them (30%) had developed osteoporosis. After 12 months, 20 of 32 evaluable patients (62%) had BMD values below normal and nine of them (28%) had osteoporosis. Increased pyridinium excretion was observed in 12/20 patients (60%) with acute leukemias, but only in 3/13 (23%) with CML (P = 0.014). A prolonged vitamin D deficiency for more than 6 months developed early after SCT in all patients. Patients with acute leukemias frequently have osteopenia and osteoporosis before SCT. After SCT, a further loss of BMD occurs independent from the underlying disease. Standard prophylactic measures are not sufficient to prevent loss of bone mass. Studies on prophylactic interventions are needed to prevent severe osteoporosis in long-term survivors of SCT.

Glucocorticoid-induced osteoporosis

Glucocorticoid-induced osteoporosis is a significant problem in patients receiving glucocorticoids after transplantation and for the treatment of parenchymal renal disease and rheumatological disorders. Frequently, patients are not evaluated or treated appropriately for glucocorticoid-induced osteoporosis. Bone loss occurs early after the administration of high-dose glucocorticoid therapy. Elderly patients with low bone densities before the initiation of glucocorticoid therapy are at particular risk of developing significant bone loss that could result in fractures. New information is now available concerning the mechanisms by which glucocorticoid-associated bone disease occurs. New therapies with anti-resorptive agents such as bisphosphonates and with anabolic agents such as parathyroid hormone offer the prospect of effective treatment of glucocorticoid-induced osteoporosis.

Changes in calcaneal trabecular bone structure after heart transplantation: an MR imaging study

PURPOSE

To use high-spatial-resolution magnetic resonance (MR) imaging to analyze the trabecular bone structure of the calcaneus in patients before and after heart transplantation and to compare this technique with bone mineral density (BMD) measurement in predicting therapy-induced bone loss and vertebral fracture status.

MATERIALS AND METHODS

High-spatial-resolution 1.5-T MR imaging of the calcaneus was performed in 40 men 11-120 months after heart transplantation, in 11 men before heart transplantation, and in 10 age-matched male volunteers. Sagittal and transverse T1-weighted spin-echo images with a voxel size of 0.195 x 0.195 x 1.000 mm were obtained, and structure measurements analogous to bone histomorphometric values were calculated. In addition, the BMD of the lumbar spine was determined in the transplant recipients pre- and postoperatively by using quantitative computed tomography, and vertebral fracture status was assessed.

RESULTS

Significant differences in structure and BMD measurements were found between patients before and after heart transplantation (P <. 05). In 17 (42%) of 40 transplant recipients, vertebral fractures were found. Although structure measurements were significantly different between patients with and those without fractures (P <.05), BMDs were not. Correlations between time after transplantation and some structure measurements were moderately significant (P <. 05), but such correlations with BMD measurements were not.

CONCLUSION

MR imaging-derived structure measurements in the calcaneus are useful for monitoring bone changes after heart transplantation and assessing vertebral fracture status.