Structural skeletal impairment induced by immunosuppressive therapy in rats: cyclosporine A vs tacrolimus

Maxillary and Mandibular Healing After Facial Allotransplantation

INTRODUCTION

Facial transplantation has emerged as a viable option in treating devastating facial injuries.Despite the high healing rate of Le Fort III and bilateral sagittal split osteotomies (BSSO) in nontransplant patients, few studies have reported assessment of maxillary and mandibular healing in face transplant patients compared with nontransplant patients. The aim of this study was to examine differences in bone healing in our patients.

PATIENTS AND METHODS

A retrospective chart review was conducted of facial allotransplantation patients at the Cleveland Clinic from December 2008 to inception. Demographics such as age, date of birth, and sex were recorded. Additional variables included procedures, revisions, reoperations, medications, and bone stability and healing. Computed tomography (CT) images assessed the alignment of skeletal components, bony union quality, and stability of fixation.

RESULTS

Three patients were included: 2 had Le Fort III segment transplantation, and 1 had transplantation of both a Le Fort III segment and mandibular BSSO. The Le Fort III segment in all patients exhibited mobility and fibrous union at the Le Fort III osteotomy on CT. In contrast, the BSSO healed uneventfully after transplantation and revision surgery, with bony union confirmed by both CT and histology of the fixation area between the donor and recipient mandible bilaterally. No patients with midfacial fibrous union required revision of the nonunion as they were clinically asymptomatic.

CONCLUSION

Le Fort osteotomy demonstrates inferior healing in facial transplantation compared with the nontransplant population. In contrast, the successful healing in the mandible is likely owing to the high density of rich cancellous bone.

A collagen-based hydrogel containing tacrolimus for bone tissue engineering

Bone tissue engineering aims to develop bone graft structure that can heal bone defects without using autografts or allografts. The current study was conducted to promote bone regeneration using a collagen type I hydrogel containing tacrolimus. For this purpose, different amounts of tacrolimus (10 μg/ml, 100 μg/ml, and 1000 μg/ml) were loaded into the hydrogel. The resulting drug-loaded hydrogels were characterized for their porosity, swelling capacity, weight loss, drug release, blood compatibility, and cell proliferation (MTT). For functional analysis, the developed hydrogel surrounded by a film made of gelatin and polycaprolactone (PCL) was administrated in the calvarias defect of Wistar rats. The results indicated that the hydrogel has a porosity of 89.2 ± 12.5% and an appropriate swelling, drug release, and blood compatibility behavior. The in vitro results indicated that the collagen hydrogel containing 1000 μg tacrolimus was adequate in terms of cell proliferation. Finally, in vivo studies provided some evidence of the potential of the developed hydrogel for bone healing.

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

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

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

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

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

Bone metabolism and arterial stiffness after renal transplantation

BACKGROUND/AIMS

To assess the relationship between bone and vascular disease and its changes over time after renal transplantation. Metabolic bone disease (MBD) is common in chronic kidney disease (CKD) and is associated with cardiovascular (CV) disease. Following transplantation (Tx), improvement in CV disease has been reported; however, data regarding changes in bone disease remain controversial.

METHODS

Bone turnover and arterial stiffness (pulse wave velocity (PWV)) were assessed in 47 Tx patients (38 (3-191) months after Tx).

RESULTS

Bone alkaline phosphatase (BALP), osteocalcin (OC) and beta-crosslaps were significantly higher in Tx patients, and decreased significantly after one year. There was a negative correlation between BALP, OC and steroid administered (r = -0.35; r = -0.36 respectively). PWV increased in the Tx group (1.15 SD). In patients with a follow up of <24 months, PWV was correlated with BALP and beta-crosslaps (r=0.53; r = 0.69 respectively) while in the ≥24 months group, PWV was correlated with cholesterol (r=0.38).

CONCLUSIONS

Increased bone turnover and arterial stiffness are present following kidney transplantation. While bone turnover decreases with time, arterial stiffness correlates initially with bone turnover, after which the influence of cholesterol becomes significant. Non-invasive estimation of bone metabolism and arterial stiffness may help to assess CKD-MBD following renal transplantation.

Use of alendronate sodium (Fosamax) to ameliorate osteoporosis in renal transplant patients: a case-control study

Background

Renal transplant patients often have severe bone and mineral deficiencies. While the clinical effects of immunosuppressive agents like calcineurin inhibitors (CIs) and sirolimus on bone turnover are unclear, bisphosphonates are effective in bone recovery in these patients. Gender is significantly associated with osteoporosis and affects bone turnover, which is different in women and men. The effective gender-related site of action of bisphosphonates is unknown.

Methods

Initially, we enrolled 84 kidney recipients who had received their transplants at least 5 months ago; of these, 8 were excluded and 76 were finally included in the study. First bone mineral density (BMD) at the lumbar spine, hip, and femoral neck was determined using dual-energy X-ray absorptiometry (DXA) between September 2008 and March 2009. These 76 patients underwent a repeat procedure after a mean period 14 months. Immunosuppressive agents, bisphosphonates, patients' characteristics, and biochemical factors were analyzed on the basis of the BMD determined using DXA.

Results

After the 14-month period, the BMD of lumbar spine increased significantly (from 0.9 g/cm² to 0.92 g/cm², p<0.001), whereas that of the hip and femoral neck did not. Ordinal logistic regression analysis was used to show that Fosamax improved bone condition, as defined by WHO (p = 0.007). The use of immunosuppressive agents did not affect bone turnover (p>0.05). Moreover, in subgroup analysis, Fosamax increased the BMD at the lumbar spine and the hipbone in males (p = 0.028 and 0.03, respectively) but only at the lumbar spine in females (p = 0.022).

Conclusion

After a long periods after renal transplantation, the detrimental effects of steroid and immunosuppressive agents on bone condition diminished. Short-term Fosamax administration effectively improves BMD in these patients. The efficacy of Fosamax differed between male and female renal transplant patients.

Long-term outcome after liver transplantation

Liver transplantation is a life-saving therapy for patients with end-stage liver disease, acute liver failure, and liver tumors. Over the past 4 decades, improvements in surgical techniques, peritransplant intensive care, and immunosuppressive regimens have resulted in significant improvements in short-term survival. Focus has now shifted to addressing long-term complications and improving quality of life in liver recipients. These include adverse effects of immunosuppression; recurrence of the primary liver disease; and management of diabetes, hypertension, dyslipidemia, obesity, metabolic syndrome, cardiovascular disease, renal dysfunction, osteoporosis, and de novo malignancy. Issues such as posttransplant depression, employment, sexual function, fertility, and pregnancy must not be overlooked, as they have a direct impact on the liver recipient's quality of life. This review summarizes the latest data in long-term outcome after liver transplantation.

IINFLUENCE OF THE IMMUNOSUPPRESSANT TACROLIMUS (FK-506) ON THE FLEXURAL STRENGTH OF FEMUR: A STUDY IN RATS

Objective: To evaluate the resistance to femoral fractures among rats treated with the immunosuppressant tacrolimus FK-506 and compare these to untreated rats and rats treated with placebo. Methods: Ninety male Wistar rats were used. The animals were nine weeks old and weighed between 220 g and 280 g. The immunosuppressive agent tacrolimus was used in this study at a dose of 2 mg/kg/day, administered orally. The suspension was administered using an insulin syringe, and the maintenance therapeutic dose was sufficient to maintain the immunosuppressive activity. The animals were randomly divided into three groups (n = 30): group 1, no substance administered; group 2, administration of the immunosuppressant tacrolimus FK-506; and group 3, administration of the vehicle alone. Treatment with FK-506 was administered for 28 days. Total leukocyte counts and differential counts (lymphocytes, monocytes, eosinophils and neutrophils) were evaluated in order to monitor the immunosuppressive effect. Bone densitometry analysis by means of dual-energy x-ray absorptiometry (DXA) was also performed before and after administration of the drug. To evaluate the resistance to flexion, a support device was developed so that mechanical tests using an EMIC universal testing machine could be carried out. Results: The results from the flexion resistance tests showed statistical differences between groups 1 and 2 (p = 0.001) and between groups 2 and 3 (p = 0.001). No statistical difference was found between groups 1 and 3 (p = 0.995). Conclusions: The femurs of rats treated with the immunosuppressive agent had lower mechanical strength than did those of normal rats and those that received placebo.

Autologous chondrocyte implantation to repair knee cartilage injury: ultrastructural evaluation at 2 years and long-term follow-up including muscle strength measurements

Autologous chondrocyte implantation (ACI) usually results in improvement in clinical scores. However, long-term isokinetic muscle strength measurements have not been reported. Biopsies from the repair tissue have shown variable proportions of hyaline-like cartilage. In this study, 21 consecutive patients were treated with autologous cartilage implantations in the knee. Mean size of the lesions was 5.5 cm(2). Follow-up arthroscopy with biopsy was performed at 2 years in 19 patients. The biopsies were examined with both light microscopy and transmission electron microscopy (TEM) techniques including immunogold analysis of collagen type 1. Patient function was evaluated with modified 10-point scales of the Cincinnati knee rating system obtained preoperatively and at 1 and 8.1 years. Isokinetic quadriceps and hamstrings muscle strength testing was performed at 1, 2 and 7.4 years. Light microscopy and TEM both showed predominately fibrous cartilage. The immunogold analysis showed a high percentage of collagen type I. At 7.4 years, the total work deficits when compared with the contra-lateral leg for isokinetic extension were 19.1 and 11.4%, and for isokinetic flexion 11.8 and 8.5% for 60 and 240 masculine/s, respectively. Mean pain score improved from 4.3 preoperatively to 6.3 at 1 year (p = 0.031) and 6.6 at 8.1 years (p = 0.013). Overall health condition score improved from 4.1 preoperatively to 6.1 at 1 year (p = 0.004) and 6.5 at 8.1 years (p = 0.008). Three patients later went through revision surgery with other resurfacing techniques and are considered failures. In summary, the formation of fibrous cartilage following ACI was confirmed by TEM with immunogold histochemistry. Although the functional scores were generally good, strength measurements demonstrated that the surgically treated leg remained significantly weaker.

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

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

Levetiracetam, Phenytoin, and Valproate Act Differently on Rat Bone Mass, Structure, and Metabolism

PURPOSE

Long-term treatment with antiepileptic drugs (AEDs) is associated with increased risk of fractures. Phenytoin (PHT) and valproate (VPA) have both been suggested to influence bone health, whereas levetiracetam (LEV) is scarcely studied. The present study compares the effect of these AEDs on bone mass, biomechanical strength, and bone turnover in rats.

METHODS

Female rats received PHT (50 mg/kg), VPA (300 mg/kg), or LEV (50 and 150 mg/kg) for 90 days. Dissected femurs were analyzed using dual energy x-ray absorptiometry (DXA), three-point cantilever bending, and histomorphological evaluation. Serum levels of biochemical bone turnover markers were monitored using immunoassay quantification.

RESULTS

PHT and VPA reduced bone mineral density (BMD) and content (BMC) in one or more bone compartments, whereas LEV did not. VPA induced increased bone turnover, whereas modest changes were observed for PHT. Interestingly, low-dose LEV was associated with reduced biomechanical strength of the femoral neck (mainly trabecular bone). In addition, low-dose LEV treatment resulted in significantly reduced levels of serum osteocalcin, a marker of bone formation. Histomorphological analyses indicated increased retention of cartilage remnants at the growth plate metaphysis of rats treated with low-dose LEV vs. controls.

CONCLUSIONS

PHT, VPA, and LEV exert differential effects on bone mass and strength, suggesting different mechanisms of action. The weakening effect of low-dose LEV on the femoral neck, despite a constant BMD, suggests a primary effect on bone quality. These findings warrant further human studies of possible adverse effects of LEV on bone development and growth, particularly in children and adolescents.

Bone alterations in children and young adults with renal transplant assessed by phalangeal quantitative ultrasound

BACKGROUND

Bone alterations in young renal transplant recipients were investigated in several studies with conflicting results. Quantitative ultrasound of the phalanges is a recently developed noninvasive procedure to assess skeletal status.

STUDY DESIGN

Cross-sectional study at a single transplant center with values compared with previously studied healthy controls.

SETTINGS & PARTICIPANTS

40 children and young adult recipients of renal grafts (15 females, 25 males; age, 20.0 +/- 8.4 years) studied 7.1 +/- 3.8 years after kidney transplantation.

PREDICTOR

Clinical, biochemical, and therapeutic features, including calcium, phosphate, and intact parathormone levels; and cumulative dosages of glucocorticoids and cyclosporine administered since transplantation.

OUTCOME & MEASUREMENT

Phalangeal quantitative ultrasound, including amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT), mainly dependent on mineral density and cortical thickness, respectively. Age- and sex-matched healthy controls were used to provide age-related z scores; sex- and height-matched healthy subjects, to provide z scores related to statural age.

RESULTS

Mean z scores of AD-SoS and BTT were -0.05 +/- 1.59 and -0.54 +/- 1.17, respectively (P > 0.05 and P < 0.001, respectively). Multivariate analysis showed that AD-SoS z score was associated significantly with body mass index, intact parathormone level, cumulative glucocorticoids administered in the first posttransplantation year, and cyclosporine administered since transplantation (model r(2) = 0.79; P < 0.001); BTT z score was associated significantly with glucocorticoid dosage in the first posttransplantation year and age (model r(2) = 0.55; P < 0.001).

LIMITATIONS

Absence of other measures of bone structure and longitudinal measures and comparison to a noncurrent control group.

CONCLUSIONS

Children and young adults may have decreased cortical thickness with maintained overall mineral density after renal transplantation. The findings of phalangeal quantitative ultrasound parallel observations using other imaging techniques. Phalangeal quantitative ultrasound may be a useful method to assess bone alternations after renal transplantation.

Conversion of immunosuppressive monotherapy from cyclosporin a to tacrolimus reverses bone loss in rats

Tacrolimus is used for transplant patients with refractory graft rejection and those with intolerance to cyclosporin (CsA), without the disfiguring adverse effects frequently attributed to CsA therapy. Since we have shown that CsA-associated bone loss can also affect alveolar bone, the purpose of this study was to evaluate the effects of conversion of monotherapy from CsA to tacrolimus on alveolar bone loss in rats. Groups of rats were treated with either CsA (10 mg/kg/day, s.c.), tacrolimus (1 mg/kg/day, s.c.), or drug vehicle for 60 and 120 days, and an additional group received CsA for 60 days followed by conversion to tacrolimus for a further 60-day period. Bone-specific alkaline phosphatase (BALP), tartrate-resistent acid phosphatase (TRAP-5b), calcium (Ca(2+)), interleukin (IL)-1beta, IL-6, and tumor necrosis factor alpha (TNF-alpha) concentrations were evaluated in the serum. Analyses of bone volume, bone surface, number of osteblasts, and osteoclasts were performed. Treatment with CsA for either 60 or 120 days was associated with bone resorption, represented by lower bone volume and increased number of osteoclasts; serum BALP, TRAP-5b, IL-1beta, IL-6, and TNF-alpha were also higher in these animals. After conversion from CsA to tacrolimus, all the altered serum markers returned to control values in addition to a significant increase of bone volume and a lower number of osteoclasts. This study shows that conversion from CsA to tacrolimus therapy leads to a reversal of the CsA-induced bone loss, which can probably be mediated by downregulation of IL-1beta, IL-6, and TNF-alpha production.

Long-Term Evolution of Body Composition After Renal Transplantation: 5-Year Survey

BACKGROUND

Thanks to advancements in immunosuppression, patients are living longer with kidney transplants, and nonimmunologic factors (particularly nutritional) have become a major source of morbidity and mortality after successful kidney transplantation (KTx). In this current study, we have prospectively assessed, in a cohort of kidney transplant recipients (KTR), the course of some nonimmunologic factors liable to hinder the long-term outcome of KTR.

METHODS

Forty-four consecutive KTR with stable functioning grafts received dietary recommendations and were on the lowest effective dose of steroids. Biochemical nutritional markers, C-reactive protein, lipid profile, and body composition determined by dual-energy X-ray absorptiometry were studied over the first year, 2 years, and 5 years after KTx.

RESULTS

No patients died during the follow-up. All patients but 2 were considered normotensive. Clinical diabetes developed in 3 patients. Visceral proteins stabilized at a normal range after the first year. Most of the patients normalized their inflammatory status. A significant improvement in lipid profile was observed. Female patients had a significant increase of weight (13.5%), mainly because of an increase in fat mass: 3.4 kg (19.4%) at 1 year and 5.6 kg (29.7%) at 2 years. In male patients, body composition remained stable and close to baseline values. The evolution of bone mass varied according to gender, total corticoid doses, and calcineurin inhibitors. Patients on low doses of steroids normalized their Z-score over the 5-year period. The increase in bone mass (paired t-test, P = .006) was only significant in patients treated with tacrolimus (analysis of variance for repeated measures, P < .001).

CONCLUSIONS

Simple measures and dietary intervention to prevent or correct nonimmunologic disorders should permit improvement of long-term morbidity and mortality of KTR without compromising the functional outcome of their transplant.

Pamidronate and osteoporosis prevention in liver transplant recipients

Osteoporosis is a common complication in patients with end-stage liver disease and after orthotopic liver transplantation (LT), with resulting increasing fracture rate. In this study, we investigated the role of treatment with pamidronate in preventing further bone loss after LT. Eighty-five patients with end-stage liver disease were included in the study. Pamidronate 30 mg was given intravenously every 3 months after LT for the duration of 1 year to 43 patients with osteopenia or osteoporosis prior LT. The remainders served as controls. All patients received a supplementation of calcium and vitamin D. Bone mineral density (BMD) at the lumbar spine and the femoral neck, and markers of bone metabolism were measured before and 12 months after LT. Sixty-two BMD were available at 12 months; only paired BMD were evaluated. A significant increase in lumbar spine BMD was observed in pamidronate treated patients. No change was evident in controls. Femoral neck BMD decreased in both treated and untreated patients. Osteocalcin serum levels and deoxypyridinoline urinary excretion were significantly reduced by treatment. Our study suggests that pamidronate decreases bone turnover and is effective in preventing the course of bone loss after LT, however the efficacy, at the dosage regimen employed and in a follow-up of 12 months, appears to be limited to trabecular bone, with no effect on the cortical structure of the femur.

Bone quality and healing in a swine vascularized bone allotransplantation model using cyclosporine-based immunosuppression therapy

Although vascularized bone and joint allotransplantation is a promising new treatment option for reconstructing large bone defects, the need for immunosuppressive agents to prevent rejection in these procedures poses a major problem. This problem stems from the fact that several of these agents can cause harmful side effects, such as alterations in bone quality and healing. Therefore, the purpose of this study was to determine what effect the commonly used immunosuppressant regimen cyclosporine A-based combination therapy has on bone quality and healing. In 10 pigs, vascularized bone allografts with skin and muscle components (osteomyocutaneous free flaps) were transplanted from size-matched donor animals. Recipient animals received oral cyclosporine A/mycophenolate mofetil/prednisone therapy for 90 days. Bone quality was studied before and after transplantation by measuring the bone's acoustic velocity and density and calculating the bone's elastic coefficient. Bone healing was assessed using radiographic analysis. Four animals were lost as a result of graft rejection or immunosuppression-related complications before the 90-day endpoint of the study. Although bone specimens taken from the six animals that completed the 90-day protocol had histological signs of rejection, they all seemed to have normal bone healing. Posttransplant bone density values were significantly decreased (p < 0.05) (1544.7 +/- 47.5 kg/m3) as compared with pretransplant values (1722.7 +/- 44.1 kg/m3). Results of the acoustic velocity and elastic coefficients measurements showed a significant decrease (p < 0.05) in posttransplant values (from 3503.0 +/- 165.1 meters/sec to 2963.0 +/- 54.6 meters/sec and from 21.6 +/- 2.2 GPa to 13.6 +/- 0.5 GPa, respectively), indicating diminished bone quality. The findings indicate that cyclosporine A/mycophenolate mofetil/prednisone combination therapy is ineffective in preventing bone rejection, that it decreases bone quality, and that it is associated with systemic toxicity, suggesting that this immunosuppressive regimen at the doses used in this study is not ideal for vascularized bone allotransplantation procedures.

Immunosuppression with FK506 has no influence on fracture healing in the rat

Immunosuppressant drugs like cyclosporine A and FK506 are widely used for solid organ transplantation. They are accelerating bone remodeling but cause net bone loss. The aim of this study was to investigate the effect of FK506 on fracture healing in the rat. Eighty Lewis rats were divided into four groups, which received FK506 (1 mg/kg BW) or no treatment for 2 or 4 weeks, beginning after production of a closed, nondisplaced unilateral tibial fracture. Radiographic, histological, and biomechanical studies were used to evaluate fracture healing and histomorphometric analysis of the tibial metaphysis of the intact contralateral side was performed. Radiographs revealed no difference of the healing of the control fractures compared with the fractures in the FK506-treated group at 2 and 4 weeks. The mechanical parameters of the tested contralateral intact tibiae and of the fracture callus demonstrated no difference between control and immunosuppressed animals. Tibial bone histomorphometry revealed increased measures of bone formation and bone resorption, accompanied by a significant reduction of percent trabecular area. At 4 weeks, the fractures showed osseous healing with woven bone at the fracture site and only minimal amounts of cartilage. Histological grading was not different between the control and the FK506 group at both time points. We conclude that systemic application of FK506 has no biomechanical and histological effects of experimental fracture healing in the rat. However, resorption far in excess of formation leads to a net bone loss in the trabecular bone of the tibia that has no effect on the stability of the intact bone.

Interventions for preventing bone disease in kidney transplant recipients: A systematic review of randomized controlled trials

BACKGROUND

Before renal transplantation complex abnormalities of bone metabolism exist and lead to increased risk for fracture after transplantation. This study was conducted to assess the evidence available to guide targeted treatment to reduce bone disease in transplant recipients.

METHODS

The Cochrane CENTRAL Registry, MEDLINE, and EMBASE were searched for randomized trials of interventions for bone disease after renal transplantation. Data were extracted on fracture, bone mineral density (BMD) by means of dual-energy X-ray absorptiometry, acute graft rejection, and adverse events. Analysis was performed with a random-effects model, and all results are expressed as relative risk with 95% confidence intervals (CIs).

RESULTS

Twenty-three eligible trials (1,209 patients) were identified. No trial found a reduction in risk for fracture. Bisphosphonates (7 trials; 268 patients; weighted mean difference [WMD], 7.66; 95% CI, 4.82 to 10.50), vitamin D analogues (2 trials; 51 patients; WMD, 6.13; 95% CI, 4.97 to 7.29), and calcitonin (1 trial; 31 patients; WMD, 5.00; 95% CI, 0.88 to 9.12) favorably affected the percentage of change in BMD at the lumbar spine compared with no treatment. Bisphosphonates (4 trials; 149 patients; WMD, 7.18; 95% CI, 6.22 to 8.13) and vitamin D analogues (2 trials; 51 patients; WMD, 3.73; 95% CI, 2.71 to 4.75), but not calcitonin (1 trial; 31 patients; WMD, -0.30; 95% CI, -5.00 to 4.40), had a favorable effect on BMD measured at the femoral neck compared with no treatment. The incidence of reported toxicity was low.

CONCLUSION

The trials were inadequately powered to show a reduction in risk for fracture. Bisphosphonates and vitamin D have a beneficial effect on BMD at the lumbar spine and femoral neck. With increasing survival after renal transplantation, this study stresses the importance of randomized controlled trial evidence of interventions of bone disease after renal transplantation.

Bilateral hand transplantation: bone healing under immunosuppression with tacrolimus, mycophenolate mofetil, and prednisolone

PURPOSE

Little is known about bone healing after composite tissue transplantation that requires pharmacologic immunosuppression. Bone integration and callus development were assessed in bilateral hand transplantation.

METHODS

In this study the course of callus development and callus maturation were assessed by color Doppler sonography and radiography in a double hand transplant and compared with forearm replantation.

RESULTS

After hand transplantation, ingrowth of small vessels at the bone junction was observed at week 3, calcified callus became visible at month 4, and bone union was completed at month 11. A similar time course of bone integration was observed after replantation. Plating offered sufficient stability. A recipient periostal flap is thought to have improved blood supply and favored development and induction of callus.

CONCLUSIONS

Bone healing after hand transplantation under immunosuppression with tacrolimus, mycophenolate mofetil, and prednisolone is identical to that after forearm replantation.

Absolute and relative growth of the rat craniofacial skeleton

Growth of the craniofacial region involves a mosaic of intramembranous and endochondral growth sites that grow at varying rates and mature at different times.

OBJECTIVE

The goal of this study was to compare absolute and relative growth of the craniofacial skeleton in wild-type Lewis rats to measures of somatic growth.

DESIGN

Lateral and dorsoventral X-rays of the head as well as the hindlimb were obtained weekly from 4 to 9 weeks of age. The X-rays were scanned, digitized, and selected linear distances were measured between points. Multilevel statistical models were used to generate absolute growth curves.

RESULTS

Although most growth curves were linear, several were quadratic (exhibiting a deceleration with age), and one displayed a third-order curve. Considerable variation in relative maturity was evident at the first time interval, ranging from 42% of mature (9 week) size (weight) to 97% of mature size (cranial width). Tibial length and body weight were less mature than most, but not all, craniofacial measures. With one exception (bizygomatic width), width measures were relatively more mature than vertical or depth measures. Vertical measures tended to be among the least mature of the craniofacial dimensions. Among the depth (length) measurements, there was a trend of higher maturity for cranial vault/cranial base measures and lower maturity for facial measures.

CONCLUSIONS

The wide spectrum of relative and absolute growth potentials demonstrated in this study indicate that the rodent craniofacial complex is amenable to testing the hypothesis that a component's response potential is related to its growth potential.

Strategic approaches to osteoporosis in transplantation

Recipients of stem cell transplantation are at risk for osteopenia and osteoporosis. Longitudinal studies performed in adults have shown that significant bone demineralization occurs following myeloablative therapy and subsequent immune suppression. Among children and adolescents, cross-sectional analyses indicate that younger patients are also at risk for long-term bone toxicity. Strategies to detect and manage this disorder in pediatric SCT recipients are presented.