Management of bone loss after organ transplantation

Bone Loss after Solid Organ Transplantation: A Review of Organ-Specific Considerations

This review article investigates solid organ transplantation-induced osteoporosis, a critical yet often overlooked issue, emphasizing its significance in post-transplant care. The initial sections provide a comprehensive understanding of the prevalence and multifactorial pathogenesis of transplantation osteoporosis, including factors such as deteriorating post-transplantation health, hormonal changes, and the impact of immunosuppressive medications. Furthermore, the review is dedicated to organ-specific considerations in transplantation osteoporosis, with separate analyses for kidney, liver, heart, and lung transplantations. Each section elucidates the unique challenges and management strategies pertinent to transplantation osteoporosis in relation to each organ type, highlighting the necessity of an organ-specific approach to fully understand the diverse manifestations and implications of transplantation osteoporosis. This review underscores the importance of this topic in transplant medicine, aiming to enhance awareness and knowledge among clinicians and researchers. By comprehensively examining transplantation osteoporosis, this study contributes to the development of improved management and care strategies, ultimately leading to improved patient outcomes in this vulnerable group. This detailed review serves as an essential resource for those involved in the complex multidisciplinary care of transplant recipients.

Fractal characteristics of the trabecular pattern of the mandible in patients with renal transplantation

OBJECTIVE

In this study, we examined the mandibular trabecular bone structures by performing fractal dimension (FD) analysis in patients who underwent renal transplantation (RTx).

METHODS

Our study is an observational study with 69 RTx patients and 35 control group patients. The mean FD values of the patient and control groups were calculated and compared. In addition, biochemical parathyroid hormone (PTH), serum calcium, phosphorus, alkaline phosphatase (ALP), and vitamin-D parameters and FD values of both groups were analyzed.

RESULTS

FD values were significantly lower in the patient group than in the healthy group (p < .05). In the RTx group compared to the control group, ALP (90.71 ± 34.25-66.54 ± 16.8, respectively) (p < .001) and PTH (75.76 ± 38.01-38.17 ± 12.39, respectively) (p < .001) values were higher. There was a positive correlation between the FD values and ALP (rspearman  = .305, p = .011) and a negative correlation between FD values and vitamin-D (rspearman  = .287, p = .017) of patients with RTx.

CONCLUSION

FD values were found to be lower in patients who underwent RTx compared to the control group. It should be considered that FD analysis can be a method that can be used to evaluate trabecular bone structure in patients undergoing RTx.

Coexistence of Low Muscle Mass and Osteoporosis as a Predictor of Fragility Fractures in Long-Term Kidney Transplant Recipients

INTRODUCTION

Sarcopenia and osteoporosis are highly prevalent among kidney transplant recipients (KTRs). Although osteoporosis is known to increase fracture risk in KTRs, it is unclear whether sarcopenia or osteosarcopenia is associated with this increased risk. Thus, we aimed to investigate the association of the coexistence of low muscle mass (LMM) and osteoporosis with the risk of fracture in long-term KTRs.

METHODS

Exactly 342 stable KTRs underwent dual-energy X-ray absorptiometry and skeletal muscle mass index (SMI) measurement using bioelectrical impedance analysis.

RESULTS

LMM and osteoporosis were observed in 109 (31.9%) and 93 patients (27.2%), respectively. During a follow-up period of 5.1 years, 48 (14.0%) fractures occurred. KTRs with LMM had a higher fracture risk, but this was not significant (adjusted hazard ratio [aHR] 1.82, 95% confidence interval [CI] 0.94-3.50, p = 0.073). Similar results were obtained in KTRs with osteoporosis (aHR 1.84, 95% CI 0.96-3.47, p = 0.063). We divided the KTRs into four groups according to the presence of LMM and/or osteoporosis. The cumulative incidence rates of fractures were 13.0%, 11.1%, 10.5%, and 31.3% in the KTRs without both LMM and osteoporosis, those with LMM alone, those with osteoporosis alone, and those with both, respectively. The KTRs with both LMM and osteoporosis had a 2.92fold higher risk of fractures (95% CI 1.29-6.49; p = 0.010) than those without both LMM and osteoporosis.

CONCLUSION

Long-term KTRs with the coexistence of LMM and osteoporosis had an independently higher risk of fragility fractures than those without both LMM and osteoporosis. The combination of SMI and osteoporosis definitions can be used to identify KTRs with a high fracture risk.

High risk of osteoporosis and fracture following solid organ transplantation: a population-based study

Background

Osteoporosis and fractures increase morbidity and mortality rates after solid organ transplantation (SOT), but few studies have analyzed the risk of osteoporosis and related fractures after SOT. In this retrospective cohort study, we investigated the risk of osteoporosis and fractures in different SOT recipients.

Methods

This study was a retrospective cohort study using a nationally representative database in Taiwan. We collected the data of SOT recipients and used the propensity score matching method to obtain a comparison cohort. To reduce bias, we excluded patients who had been diagnosed with osteoporosis or fracture before inclusion. All participants were followed up until the date of diagnosis as having a pathological fracture, death, or the end of 2018, whichever occurred first. The Cox proportional hazards model was used to investigate the risk of osteoporosis and pathological fracture in SOT recipients.

Results

After adjustment for the aforementioned variables, SOT recipients were observed to have a higher risk of osteoporosis (hazard ratio (HR) = 1.46, 95% confidence interval (CI): 1.29-1.65) and fracture (HR: 1.19, 95% CI: 1.01-1.39) than the general individuals. Among the different SOT recipients, the highest risk of fractures was noted in heart or lung transplant recipients, with a HR of 4.62 (95% CI: 2.05-10.44). Among the age groups, patients aged >61 years had the highest HRs for osteoporosis (HR: 11.51; 95% CI, 9.10-14.56) and fracture (HR: 11.75, 95% CI: 8.97-15.40).

Conclusion

SOT recipients had a higher risk of osteoporosis and related fractures than the general population, with the highest risks observed in patients receiving heart or lung transplants, older patients, and patients with CCI scores of >3.

Testosterone deficiency in male organ transplant recipients

Testosterone deficiency is known to affect men with increasing incidence throughout their lifespan. The clinical manifestations of testosterone deficiency, in turn, negatively impact men's quality of life and perception of overall health. The interaction of chronic systemic disease and androgen deficiency represent an area for potential intervention. Here, we explore the topic of testosterone deficiency amongst men with end-stage organ failure requiring transplantation in order to elucidate the underlying pathophysiology of androgen deficiency of chronic disease and discuss whether intervention, including testosterone replacement and organ transplantation, improve patients' outcomes and quality of life.

Intertrochanteric fracture fixation in solid organ transplant patients: outcomes and survivorship

BACKGROUND

Solid organ transplantation (SOT) recipients have complex medical and surgical risk factors; however, the outcomes of these patients undergoing surgical fixation of hip fractures are unknown. This study sought to evaluate SOT patients' outcomes and survivorship after intertrochanteric (IT) fracture fixation.

METHODS

A retrospective review identified 12 SOT patients who underwent cephalomedullary (CMN) nail fixation for IT fractures and were matched (1:2) to a cohort of 24 non-SOT IT fracture patients. Perioperative results and complications, mortality/patient survivorship, and clinical outcomes were compared between the cohorts.

RESULTS

The time from presentation to surgical fixation was within 48 h of presentation for the non-SOT patients, while only 75% of SOT patients underwent surgery within 48 h of presentation (p = 0.034). The 90-day readmission rate for SOT patients was 25% versus 13% in the non-SOT group (p = 0.38). Similarly, the SOT cohort experienced a higher rate of major medical complication (25% vs. 13%, p = 0.38). There were two (16%) reoperations in the SOT group and three (13%) in the non-SOT matched group (p = 0.99). Respectively, the 90-day and 1-year estimated patient survivorship was similar between the two cohorts: SOT patients with 92% (95% CI 54-99%) and 73% (95% CI 24-93%) versus 86% (95% CI 62-95%) and 72% (95% CI 47-86%, HR 0.92, 95% CI 0.18-4.62, p = 0.92) in non-SOT patients.

CONCLUSION

SOT patients who underwent CMN fixation for IT fractures required more time from hospital presentation to surgical management than non-SOT patients. Although not statistically significant, SOT patients demonstrated more acute complications and readmissions, but similar mortality compared to those without transplant.

Timing of Osteoporotic Vertebral Fractures in Lung and Heart Transplantation: A Longitudinal Study

Bone loss and bone fractures are common complications after organ transplantation. Many factors contribute to the pathogenesis of transplant osteoporosis, such as bone disease preceding transplantation, immunosuppressive medications, and nutritional and lifestyle factors. This study aimed to assess the incidence of vertebral fractures before and after lung and heart transplantation. This longitudinal study analyzed 213 electronic medical records of patients who underwent lung transplantation (n = 128) and heart transplantation (n = 85) at Siena University Medical Center between January 2000 and December 2018. In lung and heart transplant recipients, the bone mineral density in the femoral sub-regions show a significant decrease at post-transplantation and at follow up visits. In both lung and heart recipients, we found an increase in the fracture incidence in the first period after transplantation (19.5% vs. 50.4% in lung recipients; 9.6% vs. 25.7% in heart recipients). Moreover, in lung recipients, vertebral fractures were predicted primarily by age, BMD at the femur, and any history of fracture. In heart recipients, vertebral fractures were predicted only by history of fracture. Our study supports the recommendations for pre-transplant osteoporosis screening in patients undergoing lung transplants, and in the first period after transplantation in heart transplant recipients.

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.

Cardiac Transplantation: Update on a Road Less Traveled

Background: With an aging population, the prevalence of heart failure continues to rise. The use of guideline-directed medical therapy and mechanical circulatory support devices has helped to improve outcomes, but cardiac transplantation remains the definitive treatment for end-stage heart failure.

Methods: We provide an update on cardiac transplantation and review indications, contraindications, and important aspects of perioperative and postoperative management. We also highlight the current challenges faced by the transplant community.

Results: Advances in surgical techniques and immunosuppression have increased survival rates posttransplant. However, the risk of rejection and adverse effects from chronic immunosuppression continue to affect long-term outcomes.

Conclusion: Despite tremendous progress in the management of cardiac transplant patients, we have much opportunity to further optimize cardiac transplant waitlisting and improve posttransplant outcomes.

Is There a Correlation Between Preoperative or Postoperative Vitamin D Levels with Pseudarthrosis, Hardware Failure, and Revisions After Lumbar Spine Fusion?

BACKGROUND

Vitamin D deficiency is a well-known cause of postoperative complications in patients undergoing orthopedic surgery. Orthopedic complications seen in vitamin D deficiency include nonunion, pseudarthrosis, and hardware failure. We seek to investigate the relationship between vitamin D deficiency and outcomes after lumbar spinal fusions.

METHODS

A retrospective patient chart review was conducted at a single center for all patients who underwent lumbar spinal fusions from January 2015 to September 2017 with preoperative or postoperative vitamin D laboratory values. We recorded demographics, social history, medications, pre-existing medical conditions, bone density (dual-energy x-ray absorptiometry) T-scores, procedural details, 1-year postoperative Visual Analog Score (VAS), documented pseudarthrosis, revisions, and hardware failure. A total of 150 patients were initially included in the cohort for analysis.

RESULTS

Overall, preoperative and postoperative vitamin D levels were not significantly associated with a vast majority of the patient characteristics studied, including comorbidities, medications, or surgical diagnoses (P > 0.05). Age at surgery was significantly associated with vitamin D levels; older patients had higher serum levels of vitamin D both preoperatively (P = 0.03) and postoperatively (P = 0.01). Those with a higher average body mass index had lower vitamin D in both groups (P = 0.02). Vitamin D levels were not significantly associated with rates of postoperative pseudarthrosis, revision, or hardware complications (P > 0.05). VAS pain score at 1 year and smoking status preoperatively or postoperatively were not associated with vitamin D levels (P > 0.05).

CONCLUSIONS

Both preoperative and postoperative vitamin D levels were not significantly associated with an increased or decreased risk of pseudarthrosis, revision surgery, hardware failure, or 1-year VAS pain score after lumbar spine fusion surgery.

Osteoporosis in Children with Chronic Illnesses: Diagnosis, Monitoring, and Treatment

PURPOSE OF REVIEW

Osteoporosis is an under-recognized complication of chronic illness in childhood. This review will summarize recent literature addressing the risk factors, evaluation, and treatment for early bone fragility.

RECENT FINDINGS

Criteria for the diagnosis of pediatric osteoporosis include the presence of low trauma vertebral fractures alone or the combination of low bone mineral density and several long bone fractures. Monitoring for bone health may include screening for vertebral fractures that are common but often asymptomatic. Pharmacologic agents should be offered to those with fragility fractures especially when spontaneous recovery is unlikely. Controversies persist about the optimal bisphosphonate agent, dose, and duration. Newer osteoporosis drugs have not yet been adequately tested in pediatrics, though clinical trials are underway. The prevalence of osteoporosis is increased in children with chronic illness. To reduce the frequency of fragility fractures requires increased attention to risk factors, early intervention, and additional research to optimize therapy and potentially prevent their occurrence.

Teriparatide treatment in a heart transplant patient with a chronic kidney disease and a low-turnover bone disease: a case report

Low-turnover bone disease is a complication of chronic kidney disease and a long-term steroid therapy. Currently, the only bone anabolic treatment available is teriparatide (TPTD). So far, no data exist in heart transplant patients, and only one single case with histomorphometric analysis of a dialysis patient with a low-turnover bone disease has been published. The current report shows the effect of a 1-year TPTD therapy in a cardiac transplant patient with 10 vertebral and 3 peripheral fractures who had developed a chronic kidney failure while receiving triple immunosuppressive therapy. A transiliac bone biopsy following tetracycline labeling was performed prior and after 1 year of treatment, showing an increase in the bone formation and improvement of the structural indices (20-fold increase of osteoid volume/bone volume, fourfold increase of osteoid surface/bone surface and increases of wall thickness (+15%), trabecular thickness (+9%), and trabecular number (+38%)). Bone mineral density was stable, no new vertebral fractures had occurred, the therapy was well-tolerated, and the patient improved clinically.

Bernese Periacetabular Osteotomy in a Young Adult with an Ipsilateral Renal Transplant: A Case Report

CASE

An eighteen-year-old woman was referred to our center because of left groin pain and was diagnosed with acetabular dysplasia. The proposed treatment was a Bernese periacetabular osteotomy (PAO). The patient had undergone two renal transplants due to polycystic kidney disease; the current, functional kidney was at the lateral inguinal fossa on the left side. The patient was on chronic immunosuppressants and antihypertensive therapy.

CONCLUSION

The present case shows that PAO can be a safe procedure with good outcomes even in patients who have undergone renal transplantation.

Mineral and bone disorder after kidney transplantation

After successful kidney transplantation, accumulated waste products and electrolytes are excreted and regulatory hormones return to normal levels. Despite the improvement in mineral metabolites and mineral regulating hormones after kidney transplantation, abnormal bone and mineral metabolism continues to present in most patients. During the first 3 mo, fibroblast growth factor-23 (FGF-23) and parathyroid hormone levels decrease rapidly in association with an increase in 1,25-dihydroxyvitamin D production. Renal phosphate excretion resumes and serum calcium, if elevated before, returns toward normal levels. FGF-23 excess during the first 3-12 mo results in exaggerated renal phosphate loss and hypophosphatemia occurs in some patients. After 1 year, FGF-23 and serum phosphate return to normal levels but persistent hyperparathyroidism remains in some patients. The progression of vascular calcification also attenuates. High dose corticosteroid and persistent hyperparathyroidism are the most important factors influencing abnormal bone and mineral metabolism in long-term kidney transplant (KT) recipients. Bone loss occurs at a highest rate during the first 6-12 mo after transplantation. Measurement of bone mineral density is recommended in patients with estimated glomerular filtration rate > 30 mL/min. The use of active vitamin D with or without bisphosphonate is effective in preventing early post-transplant bone loss. Steroid withdrawal regimen is also beneficial in preservation of bone mass in long-term. Calcimimetic is an alternative therapy to parathyroidectomy in KT recipients with persistent hyperparathyroidism. If parathyroidectomy is required, subtotal to near total parathyroidectomy is recommended. Performing parathyroidectomy during the waiting period prior to transplantation is also preferred in patients with severe hyperparathyroidism associated with hypercalcemia.

Medication-induced osteoporosis: screening and treatment strategies

Drug-induced osteoporosis is a significant health problem and many physicians are unaware that many commonly prescribed medications contribute to significant bone loss and fractures. In addition to glucocorticoids, proton pump inhibitors, selective serotonin receptor inhibitors, thiazolidinediones, anticonvulsants, medroxyprogesterone acetate, aromatase inhibitors, androgen deprivation therapy, heparin, calcineurin inhibitors, and some chemotherapies have deleterious effects on bone health. Furthermore, many patients are treated with combinations of these medications, possibly compounding the harmful effects of these drugs. Increasing physician awareness of these side effects will allow for monitoring of bone health and therapeutic interventions to prevent or treat drug-induced osteoporosis.

Characteristics of bisphosphonate-related osteonecrosis of the jaw after kidney transplantation

Renal transplantation is the definitive treatment of chronic renal failure, and osteoporosis in patients after renal transplantation is caused by the use of high-dose corticosteroids, reduced renal function, and the use of immunosuppressant. While bisphosphonates inhibit osteoclastic activities, they are the drug of choice for the treatment and prevention of osteoporosis. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) becomes a problematic issue. There are few reports on BRONJ in patients after renal transplantation, so many oral bisphosphonates commonly prescribed in patients after renal transplantation to prevent osteoporosis have no warning of BRONJ. We analyzed the records of patients with BRONJ from January 2009 to December 2010. Among the patients with BRONJ, we selected patients who underwent transplantation of the kidney. Demographic data, drug-related factors, and clinical characteristics were evaluated using chart review. A total of 128 patients were categorized as having BRONJ, and there were 3 patients with a history of kidney transplantation. The average age was 54.6 years, and 2 victims were men. All patients received oral bisphosphonates for more than 2 years (range, 2-7 y; average, 58.6 mo). All patients had hypertension, diabetes mellitus, history of high-dose corticosteroids, and taking immunosuppressant drugs. Bisphosphonate-related osteonecrosis of the jaw occurred in the maxilla in all patients, which is classified as stage 3 because of the involved sinus. Extraction was the main provoking factor in all patients. In conclusion, even at a relatively young age, BRONJ in the maxilla can be developed by intake of oral bisphosphonate after kidney transplantation. Dental care for patients before and after undergoing renal transplantation should be emphasized to reduce the risk of BRONJ.

Bone disease in organ transplant patients: pathogenesis and management

Bone disease is common in recipients of kidney, heart, lung, liver, and bone marrow transplants, and causes debilitating complications, such as osteoporosis, osteonecrosis, bone pain, and fractures. The frequency of fractures ranges from 6% to 45% for kidney transplant recipients to 22% to 42% for heart, lung, and liver transplant recipients. Bone disease in transplant patients is the sum of complex mechanisms that involve both preexisting bone disease before transplant and post-transplant bone loss due to the effects of immunosuppressive medications. Evaluation of bone disease should preferably start before the transplant or in the early post-transplant period and include assessment of bone mineral density and other metabolic factors that influence bone health. This requires close coordination between the primary care physician and transplant team. Patients should be stratified based on their fracture risk. Prevention and treatment include risk factor reduction, antiresorptive medications, such as bisphosphonates and calcitonin, calcitriol, and/or gonadal hormone replacement. A steroid-avoidance protocol may be considered.

Metabolic bone diseases in kidney transplant recipients

Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a different osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Each patient may have multiple risk factors of bone loss, such as steroids usage, hypogonadism, persistent hyperparathyroidism (HPT), poor allograft function, metabolic acidosis, hypophosphatemia, vitamin D deficiency, aging, immobility and chronic disease. Clinical management requires a comprehensive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D, bisphosphonates, calcitonin as well as treatment of hypogonadism and HPT. Novel approach to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fracture rate in kidney transplant recipients.

Patients with cirrhosis and ascites have false values of bone density: implications for the diagnosis of osteoporosis

The effect of ascites on bone densitometry has been assessed in 25 patients with advanced cirrhosis, and it was concluded that ascites over 4 l causes inaccuracy of BMD measurements, particularly at the lumbar spine. This fact must be considered when assessing bone mass in patients with decompensated cirrhosis.

INTRODUCTION

Bone mineral density (BMD) measured by dual-energy x-ray absorptiometry (DXA) is the best procedure for assessment of osteoporosis and fracture risk, but BMD values at the central skeleton may be influenced by changes in soft tissues. Therefore, we have studied the effect of ascites on BMD.

METHODS

BMD was measured by DXA at the lumbar spine, femoral neck and total hip, just before and shortly after therapeutic paracentesis in 25 patients with advanced liver cirrhosis. Changes in BMD, lean and fat mass, abdominal diameter and weight, as well as the amount of removed ascites were measured.

RESULTS

The amount of drained ascites was 6.6 ± 0.5 l (range: 3.0 to 12.7 l). After paracentesis, BMD increased at the lumbar spine (from 0.944 ± 0.035 to 0.997 ± 0.038 g/cm(2), p < 0.001) and at the total hip (from 0.913 ± 0.036 to 0.926 ± 0.036 g/cm(2), p < 0.01). Patients with a volume of drained ascites higher than 4 l showed a significant increase in lumbar BMD (7.0%), compared with patients with a lower amount (1.5%) (p < 0.03). The decrease in total soft tissue mass correlated with the amount of removed ascites (r = 0.951, p < 0.001). Diagnosis of osteoporosis or osteopenia changed after paracentesis in 12% of patients.

CONCLUSION

Ascites over 4 l causes inaccuracy of BMD measurements, particularly at the lumbar spine. This fact must be considered when assessing bone mass in patients with advanced cirrhosis.

Endocrine and bone metabolic complications in chronic liver disease and after liver transplantation in children

With improved survival of orthotopic liver transplantation (OLT) in children, prevention and treatment of pre- and posttransplant complications have become a major focus of care. End-stage liver failure can cause endocrine complications such as growth failure and hepatic osteodystrophy, and, like other chronic illnesses, also pubertal delay, relative adrenal insufficiency, and the sick euthyroid syndrome. Drug-induced diabetes mellitus post-OLT affects approximately 10% of children. Growth failure is found in 60% of children assessed for OLT. Despite optimisation of nutrition, rarely can further stunting of growth before OLT be prevented. Catch-up growth is usually observed after steroid weaning from 18 months post-OLT. Whether growth hormone treatment would benefit the 20% of children who fail to catch up in height requires testing in randomised controlled trials. Hepatic osteodystrophy in children comprises vitamin D deficiency rickets, low bone mass, and fractures caused by malnutrition and malabsorption. Vitamin D deficiency requires aggressive treatment with ergocalciferol (D2) or cholecalciferol (D3). The active vitamin D metabolites alphacalcidol or calcitriol increase gut calcium absorption but do not replace vitamin D stores. Prevalence of fractures is increased both before OLT (10%-28% of children) and after OLT (12%-38%). Most fractures are vertebral, are associated with low spine bone mineral density, and frequently occur asymptomatically, but they may also cause chronic pain. Fracture prediction in these children is limited. OLT in children is also associated with a greater risk of developing avascular bone necrosis (4%) and scoliosis (13%-38%). This article reviews the literature on endocrine and skeletal complications of liver disease and presents preventive screening recommendations and therapeutic strategies.

Premenopausal osteoporosis: how to treat?

There is no agreement in defining osteoporosis in premenopausal women and diagnosis must be done carefully and not based on densitometric parameters. One must take into account the presence of other risk factors and history of fragility fractures, diseases or drugs that cause bone loss. Over 50% of premenopausal women with osteoporosis will have a secondary cause, with the remainder diagnosed with idiopathic osteoporosis. Therapeutic considerations are limited by a few studies in this group of patients, especially in regard to the risk of fractures. On the other hand, the FRAX index cannot be applied to premenopausal women. This article will review the measures to apply depending on the type of premenopausal osteoporosis, based on current scientific evidence.

Post-transplantation osteoporosis

Transplantation is an established therapy for many hematologic disorders as well as for end-stage diseases of the kidney, lung, liver, heart among others. Osteoporosis and a high incidence of fragility fractures have emerged as a complication of organ transplantation. Many factors contribute to the pathogenesis of osteoporosis following organ transplantation. In addition, most patients have some form of bone disease prior to transplantation, which is usually related to adverse effects of end-stage organ failure on the skeleton. This chapter reviews the mechanisms of bone loss that occur both in the early and late post-transplant periods including the contribution of immunosuppressive agents as well as the specific features of bone loss after kidney, lung, liver, cardiac and bone marrow transplantation. Prevention and treatment for osteoporosis in the transplant recipient will also be addressed.

Updated recommendations for the diagnosis and management of osteoporosis: a local perspective

Postmenopausal osteoporosis and osteoporosis in elderly men are major health problems, with a significant medical and economic burden. Although osteopenia and osteoporosis are more common locally than in the West, fracture rates are generally less than in Western countries. Vitamin D deficiency is common in the region and contributes adversely to bone health. Vitamin D deficiency should be suspected and treated in all subjects with ostopenia or osteoporosis. The use of risk factors to determine fracture risk has been adopted by the World Health Organization and many international societies. Absolute fracture risk methodology improves the use of resources by targeting subjects at higher risk of fractures for screening and management. The King Faisal Specialist Hospital Osteoporosis Working Group recommends screening for women 65 years and older and for men 70 years and older. Younger subjects with clinical risk factors and persons with clinical evidence of osteoporosis or diseases leading to osteoporosis should also be screened. These guidelines provide recommendations for treatment for postmenopausal women and men older than 50 years presenting with osteoporotic fractures for persons having osteoporosis-after excluding secondary causes-or for persons having low bone mass and a high risk for fracture. The Working Group has suggested an algorithm to use at King Faisal Specialist Hospital that is based on the availability, cost, and level of evidence of various therapeutic modalities. Adequate calcium and vitamin D supplement are recommended for all. Weekly alendronate (in the absence of contraindications) is recommended as first-line therapy. Alternatives to alendronate are raloxifene or strontium ranelate. Second-line therapies are zoledronic acid intravenously once yearly, when oral therapy is not feasible or complicated by side effects, or teriparatide in established osteoporosis with fractures.

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.

Elevated incidence of fractures in solid-organ transplant recipients on glucocorticoid-sparing immunosuppressive regimens

This study was conducted to assess the occurrence of fractures in solid-organ transplant recipients. Methods. Medical record review and surveys were performed. Patients received less than 6 months of glucocorticoids. Results. Of 351 transplant patients, 175 patients provided fracture information, with 48 (27.4%) having fractured since transplant (2-6 years). Transplants included 19 kidney/liver (50% male), 47 kidney/pancreas (53% male), 92 liver (65% male), and 17 pancreas transplants (41% male). Age at transplant was 50.8 ± 10.3 years. Fractures were equally seen across both genders and transplant types. Calcium supplementation (n = 94) and bisphosphonate therapy (n = 52) were observed, and an association with a lower risk of fractures was noted for bisphosphonate users (OR = 0.45 95% C.I. 0.24, 0.85). Fracture location included 8 (16.7%) foot, 12 (25.0%) vertebral, 3 (6.3%) hand, 2 (4.2%) humerus, 5 (10.4%) wrist, 10 (20.8%) fractures at other sites, and 7 (14.6%) multiple fractures. The estimated relative risk of fracture was nearly seventeen-times higher in male liver transplant recipients ages 45-64 years compared with the general male population, and comparable to fracture rates on conventional immunosuppressant regimens. Conclusion. We identify a high frequency of fractures in transplant recipients despite limited glucocorticoid use.

Vitamin D in solid organ transplantation with special emphasis on kidney transplantation

Within the past decades, vitamin D was identified as having additional physiological functions far beyond calcium homeostasis and bone metabolism. Stimulated by the discovery of the vitamin D receptor in a broad range of tissues as well as the expression of 1α-hydroxylase, the enzyme responsible for the activation of vitamin D, it became evident that the actions of vitamin D are not restricted to cells involved in mineral and bone metabolism. In fact, it affects proliferation, differentiation, and function of a large number of different cell types including cells of the immune system. Vitamin D receptor agonists were found to exert immunosuppressive effects on the adaptive immune system, thus being able to mediate immunologic tolerance. However, they promote the innate immune system and thereby improve the ability of the host to combat invading pathogens. This review summarizes our current understanding of vitamin D as an immunomodulatory agent with special emphasis on its clinical implications in the transplant setting.

Ibandronate increases cortical bone density in patients with systemic lupus erythematosus on long-term glucocorticoid

INTRODUCTION

The purpose of this research is to assess the effects of oral ibandronate on bone microarchitecture by using high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with systemic lupus erythematosus (SLE) taking a long-term glucocorticoid.

METHODS

In this double-blind placebo-controlled study, 40 Chinese female SLE patients taking prednisolone were randomly assigned to receive either monthly oral ibandronate (150 mg) or placebo with daily 1-hydroxycholecalciferol (Alfacalcidol; 1 μg) and calcium supplement for 12 months. Assessments of bone microarchitecture by using HR-pQCT and area bone mineral density (aBMD) of the lumbar spine and hip with dual-energy x-ray absorptiometry (DXA) were performed at baseline and 12 months.

RESULTS

No differences in baseline characteristics were found between the two groups. After 12 months, no statistical differences were noted in any of the bone densities, microarchitectural parameters, or percentage changes of these parameters, as measured with HR-pQCT or DXA between the two groups. However, within the active group, the percentage improvement was significant in cortical bone density (P = 0.023) which was absent in the placebo group. Improvement was also seen in the aBMD of both the lumbar spine (P < 0.0001) and the hip (P < 0.005). In the placebo group, the percentage increase in trabecular separation was significant (P = 0.04), and the percentage improvement in aBMD in the spine also was significant (P = 0.049).

CONCLUSIONS

Oral ibandronate treatment improves microarchitecture in SLE patients taking long-term glucocorticoid assessed with HR-pQCT, and this new technology may have a role in assessing bony changes in future longitudinal studies in SLE patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00668330.

Change in bone mineral density at one year following glucocorticoid withdrawal in kidney transplant recipients

Glucocorticoid (GC) therapy induces deleterious effects on the skeleton in kidney transplantation but studies of GC discontinuation in this population are limited. This study evaluated changes in areal bone mineral density (BMD) with GC withdrawal. Subjects were enrolled one yr after renal transplantation and randomized to continue or stop prednisone; all subjects continued cyclosporine and mycophenolate mofetil. BMD measured by dual-energy X-ray absorptiometry was performed at enrollment and repeated at one yr and values were standardized. Mean ± standard deviation of annualized change in standardized BMD between GC withdrawal vs. continuation group at the lumbar spine was +4.7% ± 5.5 vs. +0.9% ± 5.3 (p = 0.0014); total hip +2.4% ± 4.2 vs. -0.4% ± 4.2 (p = 0.013), and femoral neck +2.1% ± 4.6 vs. +1.0% ± 6.0 (p = 0.37). There was no confounding by prednisone dose prior to enrollment, change in creatinine clearance, weight, or use of bone-active medications following study entry. Multivariate analysis determined that the change in BMD was positively associated with baseline alkaline phosphatase and creatinine clearance and negatively associated with baseline BMD. BMD improves with GC withdrawal after renal transplantation, and this gain in BMD is dependent on the baseline bone turnover, renal function, and BMD.

Suppressive effects of 1,4-dihydroxy-2-naphthoic acid administration on bone resorption

SUMMARY

The main component of the metabolic by-products of fermentation by Propionibacterium freudenreichii ET-3 is 1,4-dihydroxy-2-naphthoic acid (DHNA), which has a naphthoquinone skeleton, as in vitamin K2. This study showed that DHNA improved bone mass reduction with osteoporosis model mice caused by FK506.

INTRODUCTION

Growth of the intestinal bacterium Lactobacillus bifidus is specifically facilitated by DHNA. The present study used osteoporosis model mice to investigate the effects of DHNA on bone remodeling.

METHODS

FK506, an immunosuppressant, was used to prepare osteoporosis model mice. Thirty mice were divided into three groups: FK group, FK+DHNA group, and control group. In the FK group, FK506 was administered to induce bone mass reduction. In the FK-DHNA group, FK506 and DHNA were administered concurrently to observe improvements in bone mass reduction. To ascertain systemic and local effects of DHNA, we investigated systemic pathological changes in colon, kidney function and cytokine dynamics, and morphological and organic changes in bone and osteoclast dynamics as assessed by culture experiments.

RESULTS

Compared to the FK group without DHNA, colon damage and kidney dysfunction were milder for FK+DHNA group, and production of inflammatory cytokines (interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha) was more suppressed. Furthermore, compared to the group without DHNA, histological analyses and radiography showed that bone resorption was suppressed for the DHNA group. Culture experiments using osteoclasts from murine bone marrow showed osteoclast suppression for the DHNA group compared to the group without DHNA.

CONCLUSION

These results show that DHNA has some effects for improving bone mass reduction caused by FK506.

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.

Prevention of premature ovarian failure and osteoporosis induced by irradiation using allogeneic ovarian/bone marrow transplantation

BACKGROUND

Two side effects of irradiation are premature ovarian failure (POF) and osteoporosis, both of which are concerns not only clinically, for patients, but also experimentally, for animals. We examine whether bone marrow transplantation (BMT) can correct the POF induced by radiation and also address whether allogeneic ovarian transplantation (OT) can modulate the adverse effects of radiotherapy.

METHODS

Eight-week-old female C57BL/6 mice were lethally irradiated with 6 Gy x2, and then injected with allogeneic bone marrow cells into their bone marrow cavity using our previously described intrabone marrow (IBM)-BMT technique. Allogeneic ovaries were simultaneously transplanted under the renal capsules of the mice.

RESULTS

Three months after the transplantation, we noted that hematopoietic and lymphoid cells had been successfully reconstituted. The ovaries transplanted under the renal capsules demonstrated signs of development with a large number of differentiating follicles at different stages of development. Importantly, the total bone mineral density of the tibia in the "IBM-BMT+OT" (BMT/OT) group remained normal. However, the reproductive function of the recipient mice was not restored, despite the presence of many immature oocytes in the host ovaries in the BMT/OT group. In the BMT group, no oocytes were found in the host ovaries.

CONCLUSIONS

These findings suggest that IBM-BMT with ovarian allografts can be advantageous for young women with POF and osteopenia or osteoporosis that is due to chemotherapy and radiotherapy for malignant diseases.

Approach to the patient with transplantation-related bone loss

Transplantation is an established therapy for end-stage diseases of the kidney, endocrine pancreas, heart, liver, lung, intestines and for many hematological disorders. Current immunosuppressive regimens with glucocorticoids and calcineurin inhibitors produce excellent patient and graft survival rates. This has resulted in both increases in transplant numbers and an increased recognition of previously neglected long-term complications of transplantation such as fractures and osteoporosis. Both pretransplantation bone disease and immunosuppressive therapy result in rapid bone loss and increased fracture rates. Patients are particularly at risk early after transplantation. The bone health of candidates for organ transplantation should be assessed with bone densitometry of the hip and spine. Spinal x-rays should be performed to diagnose prevalent fractures. Any secondary causes of osteoporosis should be identified and treated. Vitamin D deficiency should be corrected with vitamin D doses selected to achieve a serum 25-hydroxyvitamin D concentration of at least 20 ng/ml. All patients should receive calcium. Patients with kidney failure should be evaluated and treated for chronic kidney disease-mineral and bone disorder, including renal osteodystrophy. Secondary hyperparathyroidism, in particular, should be treated. Treatment is indicated in the immediate posttransplantation period irrespective of bone mineral density because further rapid 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. Oral and iv 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.

Effect of teriparatide on early bone loss after kidney transplantation

Kidney transplantation is associated with bone loss and a high risk of fractures. Prophylactic treatment of bone is therefore recommended in the early posttransplant period. As a large number of transplant recipients develop adynamic renal osteodystrophy, recombinant parathyroid hormone (rPTH) could be a promising therapeutic option. In a 6-month double-blind, randomized trial, 26 kidney transplant recipients were treated with daily subcutaneous injections of 20 microg teriparatide (PTH 1-34) or placebo. Bone mineral density (BMD) of the femoral neck, lumbar spine and radial bone was measured at transplantation and after 6 months. Paired bone biopsies for histomorphometric analysis were obtained in six, and for measurement of bone matrix mineralization in five patients of each group. Serologic bone markers were measured at baseline and every 3 months. A total of 24 out of 26 patients completed the study. Femoral neck BMD was stable in the teriparatide group, but decreased significantly in the placebo group. Lumbar spine and radial BMD, histomorphometric bone volume and bone matrix mineralization status remained unchanged in both groups. Serologic bone markers were similarly reduced in both groups throughout the study. We conclude that teriparatide does not improve BMD early after kidney transplantation. Neither histological analysis nor bone markers provide evidence of improved bone turnover or mineralization.

Short-term effects of high-dose zoledronic acid treatment on bone mineralization density distribution after orthotopic liver transplantation

Patients with "hepatic" bone disease exhibit increased fracture incidence. The effects on bone material properties, their changes due to orthotopic liver transplantation (OLT), as well as zolendronate (ZOL) treatment have not yet been investigated. We studied bone mineralization density distribution (BMDD) in paired transiliacal biopsies (at and 6 months after OLT) from patients (control CON n = 18, treatment group ZOL n = 21, the latter treated with i.v. ZOL at doses of 4 mg/month) for how bone at the material level was affected by the "hepatic" disease in general, as well as by OLT and ZOL in particular. (1) BMDD parameters at baseline reflected disturbed bone matrix mineralization in "hepatic" bone disease combined with low turnover. Trabecular bone displayed a decrease in mean and most frequent calcium concentration (Ca(MEAN) -2.9% and Ca(PEAK) -2.8%, respectively; both P < 0.001), increased heterogeneity of mineralization (Ca(WIDTH) +12.2%, P = 0.01), and increased percentage of bone areas with low mineralization (Ca(LOW) +32.4%, P = 0.02) compared to normal; however, there were no differences compared to cortical bone. (2) Six months after OLT, ZOL-treated trabecular bone displayed reduced Ca(LOW) (-32.0%, P = 0.047), cortical bone increased Ca(MEAN) (+4.2%, P = 0.009), increased Ca(PEAK) (+3.3%, P = 0.040), and decreased Ca(LOW) (-55.7, P = 0.038) compared to CON and increased Ca(MEAN) compared to baseline (+1.9, P = 0.032) without any signs of hyper- or defective mineralization. These changes as consequence of the antiresorptive action of ZOL visible already after 6 months result in beneficial effects on bone matrix mineralization, likely contributing to the significant decrease in fracture incidence observed in these patients 2 years post transplantation.

Evaluation and management of bone disease and fractures post transplant

Bone disease is common in recipients of kidney, liver, heart, and lung transplants and results in fractures in 20-40% of patients, a rate much higher than expected for age. Fractures occur because of the presence of bone disease as well as other factors such as neuropathy, poor balance, inactivity, and low body or muscle mass. Major contributors to bone disease include both preexisting bone disease and bone loss post transplant, which is greatest in the first 6-12 months when steroid doses are highest. Bone disease in kidney transplant recipients should be considered different from that which occurs in other solid organ transplant recipients for several reasons including the presence of renal osteodystrophy, which contributes to low bone mineral density in these patients; the location of fractures (more common in the legs and feet in these patients than in spine and hips as in other solid organ recipients); and the potential danger in using bisphosphonate therapy, which may cause more harm than good in kidney transplant recipients with low bone turnover. Evaluation in all patients should preferably occur in the pretransplant period or early post transplant and should include assessment of fracture risk as well as metabolic factors that can contribute to bone disease. Bone mineral density measurement is recommended in all patients even if its predictive value for fracture risk in the transplant population is unproven. Management of bone disease should be directed toward decreasing fracture risk as well as improving bone density. Pharmacologic and nonpharmacologic treatment strategies are discussed in this review. Although there have been many studies describing a beneficial effect of bisphosphonates and vitamin D analogues on bone density, none have been powered to detect a decrease in fracture rate.

Bisphosphonates and bone fractures in long-term kidney transplant recipients

BACKGROUND

There is little information on the role of bisphosphonates and bone mineral density (BMD) measurements for the follow-up and management of bone loss and fractures in long-term kidney transplant recipients.

METHODS

To address this question, we retrospectively studied 554 patients who had two BMD measurements after the first year posttransplant and compared outcomes in patients treated, or not with bisphosphonates between the two BMD assessments. Kaplan-Meier survival and stepwise Cox regression analyses were performed to examine fracture-free survival rates and the risk-factors associated with fractures.

RESULTS

The average time (+/-SE) between transplant and the first BMD was 1.2+/-0.05 years. The time interval between the two BMD measurements was 2.5+/-0.05 years. There were 239 and 315 patients in the no-bisphosphonate and bisphosphonate groups, respectively. Treatment was associated with significant preservation of bone loss at the femoral neck (HR 1.56, 95% CI 1.21-2.06, P=0.0007). However, there was no association between bone loss at the femoral neck and fractures regardless of bisphosphonate therapy. Stepwise Cox regression analyses showed that type-1 diabetes, baseline femoral neck T-score, interleukin-2 receptor blockade, and proteinuria (HR 2.02, 0.69, 0.4, 1.23 respectively, P<0.01), but not bisphosphonates, were associated with the risk of fracture.

CONCLUSIONS

Bisphosphonates may prevent bone loss in long-term kidney transplant recipients. However, these data suggest a limited role for the initiation of therapy after the first posttransplant year to prevent fractures.

Management of metabolic bone disease in kidney transplant recipients

Bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a different osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Hypovitaminosis D, hyperparathyroidism and hyperaluminemia may resolve after kidney transplant, but many patients have other risk factors of bone loss, such as steroids usage, hypogonadism, persistent hyperparathyroidism, poor allograft function, aging, and chronic diseases. Clinical management requires a comprehensive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D analogues, bisphosphonates and calcitonin. Novel approaches to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fractures in kidney transplant recipients.

Does diabetes increase the risk for fractures after solid organ transplantation? A nested case-control study

To assess the risk of fractures after a solid organ transplantation among diabetic versus nondiabetic patients, we conducted a nested case-control study. Pretransplant diabetes was associated with a 2-fold increase in post-transplant fractures.

INTRODUCTION

Diabetes has been associated with osteoporosis in the general population. However, among patients receiving solid organ transplantation, the association between pretransplant diabetes and post-transplant fractures is not clear, although both diabetes and fractures are prevalent among this patient population. We aimed to determine whether pretransplant diabetes increases the risk of fractures among patients receiving solid organ transplantation.

MATERIALS AND METHODS

We conducted a nested case-control study in a cohort of subjects 18 years and older, enrolled in the Quebec Drug Insurance Plan, who received a first solid organ transplantation between January 1986 and December 2005. Cases had sustained a fracture between the date of discharge from the hospitalization for solid organ transplantation and the end of the study period. All remaining patients were eligible controls. The fracture date was the case index date. Cases were matched to up to four controls on the type of organ transplanted and the date of transplantation. The index date of a control patient was that of his/her matched case. Crude and adjusted ORs were obtained with univariate and multivariate conditional logistic regression models.

RESULTS

The study included 238 cases and 873 controls. Pretransplant diabetes was present in 30% of the cases and 22% of the controls (crude OR: 2.16; 95% CI: 1.7-2.8). After adjusting for age, sex, previous fractures, past hyperthyroidism, hospitalization duration, use of narcotics, benzodiazepines, antidepressants, loop diuretics, thiazide diuretics, glucocorticoids, immunosuppressants, estrogens, bisphosphonates, calcium, vitamin D, and calcitonin, pretransplantation diabetes remained a significant risk factor for fractures (adjusted OR: 1.94; 95% CI: 1.5-2.6). Use of narcotics (OR: 3.0; 95% CI: 2.0-4.4) and antidepressants (OR: 1.9; 95% CI: 1.2-3.1) in the month preceding the index date and use of loop diuretics in the year preceding the index date (OR: 1.4; 95% CI: 1.1-1.9) were also associated with increased risks of fractures.

CONCLUSIONS

Pretransplant diabetes seemed to significantly increase post-transplant fractures among adults receiving solid organ transplantation. Pretransplant fracture prophylaxis should be considered in these patients.

Post-transplantation osteoporosis

Osteoporosis is prevalent in transplant recipients and is related to pre- and post-transplantation factors. Low bone density and fractures may antedate transplantation, related to traditional risk factors for osteoporosis, effects of chronic illness, and end-stage organ failure and its therapy, on the skeleton. Bone loss after transplantation is related to adverse effects of immunosuppressive drugs (glucocorticoids and calcineurin inhibitors) on bone remodeling. Newer immunosuppressive medications may permit lower doses of glucocorticoids and may be associated with decreased bone loss and fractures. Bisphosphonates are currently the most effective agents for the prevention and treatment of post-transplantation osteoporosis.

Effects of bisphosphonate treatment on bone repair under immunosuppression using cyclosporine A in adult rats

The effect of cyclosporine A on bone turnover remains unclear. Using adult rats with vascularized bone transplantation, we show that long-term cyclosporine A administration increases bone turnover and zoledronic acid treatment enhances the reconstruction of cyclosporine A-administered skeleton. Bisphosphonates might be efficacious in human bone repair under immunosuppression using cyclosporine A.

INTRODUCTION

Bisphosphonate treatment effectively prevents bone loss after transplantation. However, recent evidence from gain- and loss-of-function experiments has indicated that calcineurin inhibitors, such as cyclosporine A (CsA), reduce bone turnover, and severely suppressed bone turnover might delay the union of human fractured bone. The purpose of this study was to investigate the effects of bisphosphonate treatment on the repair of CsA-administered skeleton.

METHODS

After skeletal reconstruction by vascularized tibial grafting, adult recipient rats were treated with intramuscular CsA (10 mg/kg/day) and low-dose (0.2 microg/kg/week) or high-dose (2 microg/kg/week) subcutaneous zoledronic acid alone or in combination for 8 weeks. Biochemical parameters were measured in blood and urine. The reconstructed skeleton was analyzed using soft X-ray, histology, dual energy X-ray absorptiometry, and three-point bending test.

RESULTS

CsA induced mild renal dysfunction, hyperparathyroidism and high bone turnover. High-dose zoledronic acid delayed cortical bone union at the distal host-graft junction, but its combination with CsA did not cause such a delay. High-dose zoledronic acid prevented CsA-induced bone loss and bone fragility in the reconstructed skeleton.

CONCLUSION

In this rat model, long-term CsA administration increases bone turnover, at least partly, through hyperparathyroidism and high-dose zoledronic acid treatment does not impair the union of CsA-administered bone.

[Sequelae of organ transplantation]

Transplant medicine has significantly changed the prognosis of diseases leading to terminal organ failure. It has evolved from an experimental procedure to standard therapy for liver, kidney and cardio-vascular diseases. Transplant medicine combines operative organ replacement with the management of severely ill patients before transplantation, as well as life-long follow-up of organ graft recipients. Ten year survival rates of 65% to over 90% have led to a steady increase of transplanted patients seen by general medical care providers which represents a challenge for practicing internists. Apart from organ-specific conditions, infectious, immunosuppressant-associated and metabolic consequences determine long-term survival. These include virus reactivation, graft rejection, anastomotic problems but more importantly general mortality determining factors such as diabetes, renal insufficiency and hypertension, which are often a consequence of immunosuppressant administration. They directly impact long-term survival. The awareness and treatment of these secondary conditions of organ transplantation in routine medical practice contributes significantly to secure the long term success of transplant medicine.

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.