Osteoporosis after cardiac transplantation

Bone mineral density in pediatric transplant recipients

BACKGROUND

Reduced bone mass and fragility fractures are known complications after transplantation in adults. Far less is known about the skeletal effects of transplantation in children and adolescents.

METHODS

This cross-sectional study examined the skeletal status of children (ages 9-18 years) who were at least 1 year post-cardiac (n=13), post-renal (n=8), or post-bone marrow (BMT; n=15) transplantation. Bone mass at total hip, femoral neck, spine (L2-4), and whole body (WB) was determined by dual energy x-ray absorptiometry and compared with age, sex, and ethnic-specific reference data. Standard deviations (z-scores) were calculated for both areal bone mineral density (BMD) and estimated volumetric bone density (bone mineral apparent density [BMAD]).

RESULTS

Cardiac transplant patients had significantly lower BMD z-scores compared with the reference population at all skeletal sites. BMT recipients had significantly reduced BMD z-scores at total hip, spine, and WB. Kidney transplant patients had a significantly reduced WB BMD z-score only. Spine BMAD z-scores remained significantly reduced in cardiac and BMT subjects. Three of 36 patients had radiographic evidence of spinal fracture after transplantation. No correlation between steroid dosage and any measure of bone mass was observed.

CONCLUSIONS

Cardiac and BMT recipients had reduced BMD at multiple skeletal sites, and renal transplant recipients had reduced WB BMD for age. Deficits in spine bone density persisted after correcting for small bone size using BMAD. Low bone density and the occurrence of vertebral fractures indicate that cardiac, renal, and bone marrow transplantation in children is associated with reduced bone health.

Resistance training prevents vertebral osteoporosis in lung transplant recipients

BACKGROUND

Osteoporosis and vertebral fractures are a consequence of glucocorticoid immunosuppression therapy in lung transplant recipients (LTR). The purpose of this study was to determine the therapeutic efficacy of a 6-month program of specific resistance exercise designed to reverse glucocorticoid-induced vertebral osteoporosis.

METHODS

Sixteen lung transplant candidates were randomly and prospectively assigned to a group (n=8) that performed 6 months of exercise on a lumbar extensor machine or to a control group (n=8). Resistance exercise was initiated at 2 months after transplantation. Bone mineral density (BMD) of the lumbar vertebra (L2-3) was assessed using a dual-energy X-ray absorptiometer (DXA). DXA scans were performed before and 2 months after transplantation and after 6 months of lumbar extensor training or control period.

RESULTS

Lumbar BMD did not differ (P>0.05) between the two groups at study entry. Both the trained (0.63 to 0.54 g/cm2 of hydroxyapatite) and control groups (0.62 to 0.53 g/cm2 of hydroxyapatite) lost significant and comparable amounts (-14.5%) of BMD between study entry and 2 months posttransplantation. The control group lost further (P<or=0.05) lumbar BMD between 2 and 8 months posttransplantation (0.53 to 0.50 g/cm2 of hydroxyapatite), decreasing to values that were 19.5% less than pretransplantation baseline. Lumbar BMD in the trained group increased significantly (+9.2%) after 6 months (0.54 to 0.60 g/cm2 of hydroxyapatite) and returned to values that were within 5% of pretransplantation baseline.

CONCLUSION

Mechanical loading associated with progressive resistance exercise, using a specific exercise that isolated the lumbar spine, was efficacious in preventing steroid-induced osteoporosis in LTR.

Pathogenesis of bone loss in heart transplant candidates and recipients

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Avascular necrosis in long-term survivors after allogeneic or autologous stem cell transplantation: a single center experience and a review

BACKGROUND

The most debilitating skeletal complication of stem cell transplantation (SCT) is avascular necrosis (AVN).

METHODS

Two hundred seven consecutive patients were evaluated prospectively for AVN. They survived disease free for more than 180 days after autologous or allogeneic SCT for hematologic malignancies. The diagnosis of AVN in suspicious cases was confirmed by magnetic resonance imaging. Possible correlations with treatments, bone mineral density (BMD), graft versus host disease (GVHD), and in vitro growth of fibroblast progenitors were investigated. Bone mineral density was evaluated by dual-energy X-ray absorptiometry in 100 transplanted patients, and the in vitro growth of fibroblast progenitors was monitored by a fibroblast colony-forming unit (CFU-F) assay in 30 patients after allogeneic SCT.

RESULTS

Twelve patients developed AVN 3-114 months (median, 26 months) following SCT: 10 (10%) after allogeneic SCT and 2 (1.9%) after autologous SCT (P = 0.04). Twenty-five joints were affected by AVN. All patients had femoral head involvement, which was managed with hip replacement in six of them. All but one patient who developed AVN after allogeneic SCT suffered from chronic GVHD (cGVHD). Avascular necrosis occurred 1-4 months after exacerbation or progression of cGVHD. Cumulative dose of steroids was similar in both SCT groups (including steroids given pretransplant for the basic disease), whereas treatment duration was significantly longer in the allogeneic SCT group. Avascular necrosis was related to the decreased number of bone marrow CFU-F colonies in vitro, but not to BMD values.

CONCLUSIONS

Avascular necrosis is a skeletal complication that occurs more often after allogeneic than after autologous SCT. Occurrence of AVN symptoms after clinical follow-up of cGVHD suggests that cGVHD requiring long-term steroid therapy is one of the main risk factors for AVN. Avascular necrosis may be facilitated by a severe deficit in the repopulating capacity of bone marrow stromal stem cells after SCT.

Bone mineral density changes within six months of renal transplantation

BACKGROUND

The effective use of new steroid-sparing immunosuppressive regimens may lower cumulative glucocorticoid use among renal transplant recipients. However, it is unknown what effect this therapeutic trend has had on bone disease.

METHODS

Unselected newly transplanted inpatients (n=45) were identified and comprehensively evaluated for metabolic bone disease at a median of 16 days (range 9-33) posttransplant. A follow-up evaluation was conducted a median of 5.7 months (range 4.8-9.3) later. Follow-up values for bone mineral density (BMD) and select laboratories were compared with baseline values using nonparametric statistics. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to describe the associations of baseline characteristics, select laboratory values, and cumulative prednisone and cyclosporine use with spinal BMD loss and were calculated using logistic regression.

RESULTS

A significant decrease in intact parathyroid hormone (P<0.001) and a significant increase in calcitriol (P=0.02) were noted postengraftment. At follow-up, subjects had lost a mean of 2.4% BMD at the lumbar spine (P=0.003) but did not experience significant declines at the femoral neck. The highest tertiles of cumulative prednisone (OR=28.4; 95% CI 2.5-329 and OR=15.8; 95% CI 1.4-179, respectively) and past alcohol use (OR=9.3; 95% CI 1.46-58.5) were significantly associated with spinal BMD loss.

CONCLUSIONS

Significant loss in lumbar BMD occurred within 6 months of transplantation in more than one third of a prospective cohort of renal transplant recipients. Lumbar bone loss seemed to be mediated primarily by glucocorticoid dose and a history of alcohol use.

Skeletal effects of cyclosporin A are gender related in rats

The immunosuppressive drug cyclosporin A (CsA) is thought to be involved in the pathogenesis of posttransplantation osteoporosis. To evaluate further the skeletal effects of CsA, we treated aged male and female sham-operated and gonadectomized rats with low doses of CsA for 4 months. Here, we show that CsA is antiresorptive and bone-sparing in aged female rats but increases bone resorption and reduces bone mass in aged male rats. However, even in male rats, CsA treatment, at clinically relevant doses, increased bone resorption only transiently and did not result in pronounced long-term cancellous bone loss. The gender-specific skeletal effects of CsA were not modulated by sex hormones or gonadectomy. CsA did not influence sex steroid metabolism in male or female rats. However, endogenous estradiol in sham-operated female rats (and especially, exogenous administration of 17beta-estradiol in ovariectomized rats) markedly diminished blood levels of CsA, probably by increasing hepatic CsA metabolism. Although the mechanism for the gender-specific skeletal effects of CsA is still obscure, our findings may have important implications for clinical therapy with CsA.

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

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

Secondary causes of osteoporosis

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

Prevention of osteoporosis in cardiac transplant recipients

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

Glucocorticoid-induced osteoporosis

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

Effect of ibandronate on bone loss and renal function after kidney transplantation

Severe osteoporosis frequently is observed after organ transplantation. In kidney transplantation, it adds to pre-existing renal bone disease and strategies to prevent osteoporosis are not established. Eighty kidney recipients were included in a randomized controlled prospective intervention trial. Treated patients (n = 40) received an injection of ibandronate, a bisphosphonate, immediately before and at 3, 6, and 9 mo after transplantation. The primary outcome measured was the change in bone mineral density. Secondary measures included graft outcome, spinal deformities, fracture rate, body height, and hormonal and metabolic data. Loss of spongy and cortical bone after transplantation was prevented by ibandronate. Changes of bone mineral density (ibandronate versus controls) were as follows: lumbar spine, -0.9 +/- 6.1% versus -6.5 +/- 5.4% (P < 0.0001); femoral neck, +0.5 +/- 5.2% versus -7.7 +/- 6.5% (P < 0.0001); and midfemoral shaft, +2.7 +/- 12.2% versus -4.0 +/- 10.9% (P = 0.024). Fewer spinal deformities developed with ibandronate (7 patients with 7 deformities versus 12 patients with 23 deformities; P = 0.047). Loss of body height was 0.5 +/- 1.0 cm versus 1.1 +/- 1.0 cm in control subjects (P = 0.040). Two bone fractures occurred in each group. There were fewer acute rejection episodes with ibandronate (11 versus 22; P = 0.009). Graft function after 1 yr was comparable. Bone loss, spinal deformation, and loss of body height during the first year after kidney transplantation are prevented by injection of ibandronate at intervals of 3 mo. The smaller number of rejection episodes of the ibandronate-treated group should be confirmed and its mechanism should be explored in additional studies.

Transforming growth factor-beta administration modifies cyclosporine A-induced bone loss

Cyclosporine A (CsA), a potent immunosuppressant used in transplantation, induces increased formation with excess resorption in the rat with resultant osteopenia. These findings are confirmed in the human model. Transforming growth factor-beta (TGF-beta) is reported to be involved in the coupling of bone formation with resorption and in vivo and in vitro stimulates osteoblasts, and in vitro inhibits osteoclasts. CsA stimulates secretion of TGF-beta1 in humans, which, while improving immunosuppression, may also contribute to renal toxicity. This study was performed determine whether exogenously administered TGF-beta would modify the bone effects of CsA. Male Sprague-Dawley rats, 6 months of age, were randomized to receive: TGF-beta and CsA vehicle (group A); TGF-beta 5 microg/kg three times per week and CsA vehicle (group B); TGF-beta vehicle and CsA 10 mg/kg (group C); or TGF-beta 5 microg/kg three times per week and CsA 10 mg/kg (group D). These were compared with control over 28 days. CsA, but not TGF-beta, increased serum 1,25(OH)(2)D levels throughout the study. CsA increased osteocalcin (BGP), but TGF-beta negated this effect. Histomorphometry confirmed the known effects of CsA, whereas TGF-beta alone had no effect. However, in combination, TGF-beta blocked CsA's effect and increased osteoblast recruitment and activity, as reflected by increased percent mineralizing surface, percent osteoid perimeter, bone formation rate (bone volume referent), and activation frequency. Thus, it appears as if TGF-beta administration may have potential in modulating the deleterious bone effects of CsA.

Cyclosporin A affects extracellular matrix synthesis and degradation by mouse MC3T3-E1 osteoblasts in vitro

BACKGROUND

Immunosuppressant therapy is thought to be a major contributor to post-transplant bone disease. Histological data and serum parameters suggest that Cyclosporin A (CsA) treatment causes osteopenia as a result of an altered bone turnover, but the pathogenic mechanisms of this process remain unclear. We investigate if CsA affects cell turnover and extracellular matrix (ECM) synthesis and degradation in MC3T3-E1 osteoblasts, as a surrogate model for in vivo events.

METHODS

Cells were exposed to increasing doses of CsA (0, 0.5, 1 and 5 microg/ml). Proliferation was evaluated by bromodeoxyuridine (BrdU) incorporation, viability by Trypan Blue exclusion and apoptosis by ELISA. Type I collagen was measured by ELISA and reverse transcription-polymerase chain reaction (RT-PCR), matrix metalloproteinases (MMP) by zymography and RT-PCR, and tissue inhibitors of MMP (TIMP) by reverse zymography.

RESULTS

CsA exposure for 48 h decreased osteoblast number in a dose-dependent manner in the absence of apoptosis or cytotoxicity. CsA at a dose of 5 microg/ml for 72 h caused decreased collagen type I mRNA expression and protein accumulation. While MMP-2 remained unaffected, MMP-9 activity increased. TIMP-1 activity was unaffected, while a dose-dependent increase of TIMP-2 was observed.

CONCLUSIONS

These data suggest that CsA alters ECM synthesis and degradation in MC3T3-E1 osteoblasts by decreasing type I collagen production and increasing MMP-9 activity. The combination of increased MMP-9 with unchanged TIMP-1 activity could reduce the osteoid matrix available for mineralization. In addition, decreased proliferation could further reduce the number of cells synthesizing new osteoid matrix and thus contribute to the process of bone loss.

An update on glucocorticoid-induced osteoporosis

In general, bone loss from glucocorticoid treatment occurs rapidly within the first 6 months of therapy. Glucocorticoids alter bone metabolism by multiple pathways; however, the bone loss is greatest in areas rich in trabecular bone. Preventive measures should be initiated early. It is the author's opinion that all subjects initiating treatment with prednisone at 7.5 mg or greater require calcium supplementation (diet plus supplement) at a dose of 1500 mg and vitamin D at a dose of 400 to 800 IU/d. If the patient is going to remain on this dose of glucocorticoid for more than 4 weeks, an antiresorptive agent should be started (e.g., estrogen, bisphosphonate, raloxifene). If a patient has established osteoporosis and is either initiating glucocorticoid therapy or is chronically treated with prednisone at 5 mg d or greater in addition to calcium and vitamin D supplementation, a potent antiresorptive agent (bisphosphonate) should be started. A bone mineral density measurement of either the lumbar spine or the hip may be helpful is assessing an individual's risk of osteoporosis, may improve compliance with treatment, and can be used to monitor the efficacy of the prescribed therapy. There is no reason to withhold treatment for glucocorticoid-induced bone loss until a bone mass measurement is taken, however. In motivated patients, a weight-bearing and resistance exercise program should be prescribed to help retain muscle strength and prevent depression. If hypercalciuria develops with glucocorticoid use, either thiazide diuretics or sodium restriction may be helpful. In patients who continue to lose bone or experience fracture's despite antiresorptive therapy while on glucocorticoids, bone-building anabolic agents (e.g., hPTH 1-34 or PTH 1-84) may be available someday soon.

Immunosuppressant use without bone loss--implications for bone loss after transplantation

Cyclosporine A (CsA) is associated with posttransplantation bone disease. Immunosuppressant drugs such as sirolimus (SRL), which are more potent and less deleterious than CsA, are being developed. Previous experiments have shown that SRL although immunosuppressive, is relatively bone sparing. The use of low doses of CsA and SRL in combination has displayed in vivo synergism. This study was initiated to examine the effect of low-dose CsA and SRL on bone metabolism, thereby hopefully providing a bone sparing immunosuppressive regimen for transplant recipients. One hundred and nineteen rats were divided into groups: basal, vehicle, CsA high dose, CsA low dose, SRL low dose, and combination low-dose CsA and SRL. The basal group was killed on day 0 for histomorphometry. The experimental groups were weighed and bled on days 0, 28, 56, and 84 and were killed on day 84 for histomorphometry. Serial assays for blood urea nitrogen (BUN), creatinine, and osteocalcin were performed. Osteocalcin was raised on days 28 and 56 in the high dose CsA group. Histomorphometry showed osteopenia with high-dose CsA. Low-dose CsA was relatively bone sparing, while low-dose SRL and combined low-dose CsA did not cause bone loss. In conclusion, the synergistic combination of low-dose CsA and SRL has the potential of providing both bone sparing and immunosuppressive benefits.

Post-cardiac transplantation gout: incidence of therapeutic complications

OBJECTIVE

To study the clinical impact of gout treatment following cardiac transplantation.

METHODS

We performed an audit of all cardiac transplant recipients of the Alfred Hospital before August 1998 who lived in Victoria.

RESULTS

We studied 225 patients (81% men), with a mean post-transplant follow-up of 50.8 months (SD 36). Forty-three (19%) had pre-transplant gout, 19 recurring post-transplantation. Twenty-three patients developed gout de novo. Of the 24 patients who received allopurinol, 6 developed pancytopenia and required hospitalization. Fourteen received a change in immunosuppression: in 5 patients following pancytopenia, and in 9 to enable safe use of allopurinol. Thirty-two patients received colchicine; 5 developed neuromyopathy. Impaired renal function, diuretic use, and hypertension were more common in this sub-group. Non-steroidal anti-inflammatory agents, used in 16 patients, caused serious complications in 1 patient (life-threatening peptic ulceration and hemorrhage, precipitating dialysis-dependent chronic renal failure).

CONCLUSIONS

Cardiac transplant recipients, when treated for gout, are at high risk of therapeutic complications. Thus, gout treatment significantly affects care, health, and immunosuppression of these patients.

Cyclosporine bone remodeling effect prevents steroid osteopenia after kidney transplantation

BACKGROUND

It is well established that prednisone above 7.5 mg/day may induce osteopenia in association with decreased bone formation. In contrast, the effect of cyclosporine on bone remodeling and bone mineral density (BMD) is controversial. Multiple confounding factors explain this controversy, especially after renal transplantation.

METHODS

Fifty-two renal transplanted patients never exposed to aluminum while on dialysis were selected because they had no rejection and no hypercalcemia for 24 months while being treated with low dose prednisone/cyclosporine A (daily dose at 10 mg and 4.8 mg/kg, respectively, beyond 3 months). Bone remodeling markers (BRMs; plasma osteocalcin, bone and total alkaline phosphatases for formation, and urinary pyridinolines for resorption) were sequentially measured together with plasma creatinine, intact parathyroid hormone (PTH) and 25 OH vitamin D and cyclosporine from day 0 to 24 months. BMD was measured at 3, 6, 12, and 24 months by quantitative computerized tomography (QCT) at the lumbar spine and by double-energy x-ray absorptiometry (DEXA) at this site, as well as at the femoral neck, radius shaft, and ultradistal (UD) radius.

RESULTS

Plasma concentrations of creatinine, PTH, and 25 OH vitamin D initially decreased and stabilized beyond three months at 137 micromol/L, 1.5 the upper limit of normal (ULN) and 11 ng/mL, respectively. All BRM increased significantly above the ULN at six months and then decreased. The BMD Z score at three months was low at all sites measured by DEXA and QCT. Follow-up measurements showed stability of absolute value and of Z score at all sites measured by DEXA. A comparison of the lumbar QCT Z score, which was available in 42 patients at 3 and 24 months, showed an increase in 28 and a decrease in 14, so that the increase for the whole group was significant (P < 0.04). Compared with patients with a decreased Z score, those with an increased Z score had significantly higher cyclosporine and lower prednisone dosages and a greater BRM increase at six months, whereas age, sex ratio, and plasma creatinine, PTH and 25 OH vitamin D were comparable and stable from months 3 through 24. The mean trough level of cyclosporine for the first six months was positively correlated to osteocalcin and total alkaline phosphatase increase at six months, and both bone formation and resorption marker increases were significantly correlated to the lumbar QCT Z score increase at 24 months.

CONCLUSIONS

Combined low-dose prednisone and cyclosporine immunosuppression are associated with a stabilization of BMD measured at all sites with DEXA 3 to 24 months after renal transplantation and with a prevention of age-related loss of vertebral trabecular bone, as shown by the significant increase in lumbar spine QCT Z score. It is suggested that cyclosporine, together with the decrease of prednisone dosage but independent of renal function, PTH, and vitamin D status, contributes to a transient stimulation of bone remodeling at six months, which counterbalances the deleterious effect of prednisone on bone formation and BMD.

Lesser reduction in bone mineral density by the immunosuppressant, FK506, compared with cyclosporine in rats

BACKGROUND

Posttransplantation osteopenia leading to osteoporosis induced commonly by treatment with immunosuppressants including cyclosporine (CsA) is a severe complication and results in lowering the quality of life in patients receiving organ transplantation. FK506 is a newly developed immunosuppressant and is currently being used for the prevention of rejection after organ transplantation. In this study, to investigate whether FK506 as well as CsA would cause osteopenia or not, we evaluated the effect of FK506 on bone mineral density and several parameters relevant to bone metabolism in comparison with that of CsA using normal rats.

METHODS

Ten-week-old male Sprague-Dawley rats were treated with FK506 (vehicle, 1 mg/kg, and 3.2 mg/kg) or CsA (vehicle, 10 mg/kg, and 32 mg/kg) by daily oral gavage for 28 days. Bone mineral density of the femur, plasma insulin-like growth factor I (IGF-I), and urinary deoxypyridinoline were determined by peripheral quantitative computerized tomography, radioimmunoassay, and enzyme-linked immunosorbent assay, respectively.

RESULTS

The reduction in bone mineral density of the femur was observed in both FK506- and CsA-treated rats. The reduction in CsA-treated rats, however, was statistically significant and strikingly severe, whereas that in FK506-treated rats was much less severe than CsA. Plasma IGF-I levels were significantly elevated in FK506-treated rats but not in CsAtreated rats. Urinary deoxypyridinoline levels were unchanged in FK506-treated rats but elevated in CsA-treated rats.

CONCLUSIONS

Compared with CsA, FK506 does not appear to induce severe osteopenia by high-turnover bone metabolism in the rat by mediating via IGF-I induction in part. The results suggest that FK506 may exert favorable effects on bone metabolism in patients with organ transplantation compared with CsA. To assess this idea, further clinical investigations focused on bone metabolism will be required.

Exercise following heart transplantation

During the past 2 decades, heart transplantation has evolved from an experimental procedure to an accepted life-extending therapy for patients with endstage heart failure. However, with dramatic improvements in organ preservation, surgery and immunosuppressive drug management, short term survival is no longer the pivotal issue for most heart transplant recipients (HTR). Rather, a return to functional lifestyle with good quality of life is now the desired procedural outcome. To achieve this outcome, aggressive exercise rehabilitation is essential. HTR present unique exercise challenges. Preoperatively, most of these patients had chronic debilitating cardiac illness. Many HTR have had prolonged pretransplantation hospitalisation for inotropic support or a ventricular assist device. Decrements in peak oxygen consumption (VO2peak) and related cardiovascular parameters regress approximately 26% within the first 1 to 3 weeks of sustained bed rest. Consequently, extremely poor aerobic capacity and cardiac cachexia are not unusual occurrences in HTR who have required mechanical support or been confined to bed rest. Moreover, HTR must also contend with de novo exercise challenges conferred by chronic cardiac denervation and the multiple sequelae resulting from immunosuppression therapy. There is ample evidence that both endurance and resistance training are well tolerated in HTR. Moreover, there is growing clinical consensus that specific endurance and resistance training regimens in HTR can be efficacious adjunctive therapies in the prevention of immunosuppression-induced adverse effects and the reversal of pathophysiological consequences associated with cardiac denervation and antecedent heart failure. For example, some HTR who remain compliant during strenuous long term endurance training programmes achieve peak heart rate and VO2peak values late after transplantation that approach age-matched norms (up to approximately 95% of predicted). These benefits are not seen in HTR who do not participate in structured endurance exercise training. Rather, peak heart rate and VO2peak values in untrained HTR remain approximately 60 to 70% of predicted indefinitely. However, the mechanisms responsible for improved peak heart rate, VO2peak and total exercise time are not completely understood and require further investigation. Recent studies have also demonstrated that resistance exercise training may be an effective countermeasure for corticosteroid-induced osteoporosis and skeletal muscle myopathy. HTR who participate in specific resistance training programmes successfully restore bone mineral density (BMD) in both the axial and appendicular skeleton to pretransplantation levels, increase lean mass to levels greater than pretransplantation, and reduce body fat. In contrast, HTR who do not participate in resistance training lose approximately 15% BMD from the lumbar spine early in the postoperative period and experience further gradual reductions in BMD and muscle mass late after transplantation.

Glucocorticoid-induced osteopenia in adolescent heart transplant recipients

BACKGROUND

Glucocorticoid-induced cushingoid symptoms, including osteopenia and osteoporosis are well-documented in adult heart transplant recipients (HTR). Bone mineral density (BMD) of the axial skeleton is diminished by 10% to 20% within 60 days after transplantation (Tx) and most adult HTR fulfill World Health Organization criteria for osteoporosis (BMD > 2.5 SD below norm). At present, we do not know whether glucocorticoids have similar deleterious effects in adolescent HTR.

METHODS

To determine the consequences of glucocorticoid immunosuppression on regional bone mineral density (BMD) and biochemical markers of bone metabolism in adolescent HTR, we studied 19 patients (aged 16 +/- 3) at 19 months (group mean) after Tx. We measured BMD (hydroxyapatite g/cm(2)) of the total body, lumbar spine, and pelvis using dual-energy X-ray absorptiometry (Lunar). Serum levels of bone-specific alkaline phosphatase and pyridinoline cross-links were determined by enzyme immunoassay in serum kits.

RESULTS

The BMD of the lumbar spine (-12%), femur neck (-13%), femur trochanter (-12%), and ward's triangle (-16%) were significantly (p < 0.05) lower in adolescent HTR than age- and gender-matched norms. Serum levels of alkaline phosphatase (29 +/- 6 vs 22 +/- 3 U/liter) and pyridinoline cross-links (5.3 +/- 1.1 vs 3.8 +/- 0.7 mmol/liter) were significantly (p < 0.05) elevated in adolescent HTR, compared with age- and gender-matched controls studied in our laboratory.

CONCLUSIONS

Our cross-sectional results demonstrate that BMD of the axial skeleton in adolescent HTR is significantly lower (-10% to 20%) than age-matched norms and that serum biochemical markers of bone metabolism are significantly elevated, suggesting accelerated bone turnover.

Use of oral corticosteroids and risk of fractures

Treatment with oral corticosteroids is known to decrease bone density but there are few data on the attendant risk of fracture and on the reversibility of this risk after cessation of therapy. A retrospective cohort study was conducted in a general medical practice setting in the United Kingdom (using data from the General Practice Research Database [GPRD]). For each oral corticosteroid user aged 18 years or older, a control patient was selected randomly, who was matched by age, sex, and medical practice. The study comprised 244,235 oral corticosteroid users and 244,235 controls. The average age was 57.1 years in the oral corticosteroid cohort and 56.9 years in the control cohort. In both cohorts 58.6% were female. The most frequent indication for treatment was respiratory disease (40%). The relative rate of nonvertebral fracture during oral corticosteroid treatment was 1.33 (95% confidence interval [CI], 1.29-1.38), that of hip fracture 1.61 (1.47-1.76), that of forearm fracture 1.09 (1.01-1.17), and that of vertebral fracture 2.60 (2.31-2.92). A dose dependence of fracture risk was observed. With a standardized daily dose of less than 2.5 mg prednisolone, hip fracture risk was 0.99 (0.82-1.20) relative to control, rising to 1.77 (1.55-2.02) at daily doses of 2.5-7.5 mg, and 2.27 (1.94-2.66) at doses of 7.5 mg or greater. For vertebral fracture, the relative rates were 1.55 (1.20-2.01), 2.59 (2.16-3.10), and 5.18 (4.25-6.31), respectively. All fracture risks declined toward baseline rapidly after cessation of oral corticosteroid treatment. These results quantify the increased fracture risk during oral corticosteroid therapy, with greater effects on the hip and spine than forearm. They also suggest a rapid offset of this increased fracture risk on cessation of therapy, which has implications for the use of preventative agents against bone loss in patients at highest risk.

[Clinical factors associated with bone mass loss previous cardiac transplantation]

BACKGROUND

A high prevalence of osteoporosis has been described in patients before and after cardiac transplantation. But clinical factors involved in previous bone loss in this condition are not well known. The purpose has been to study bone mineral density (BMD) in patients subject to cardiac transplantation, analyzing clinical and biochemical factors related to bone mass in these patients.

PATIENTS AND METHODS

We have studied lumbar and hip BMD in 51 patients candidates to cardiac transplantation, evaluating the functional grade of the cardiopathy, time of evolution of the disease, and antropometric and biochemical markers of bone turnover. BMD was measured using a dual X ray densitometer.

RESULTS

A significant decrease in bone mass at lumbar and hip sites was found in patients with regard to normal population. A high prevalence of osteoporosis was found (27.4%). Time of evolution of the disease prior to transplantation was found to be the most important predictive variable in bone loss at trabecular bone (lumbar spine). No modifications were found in blood routine parameters, mineral studies and in serum intact PTH. Resorption bone markers were increased and formation markers were normal, suggesting a elevated turnover osteoporosis. Patients with osteoporosis had less BMI that patients without, indicating a protective effect of body mass. Patients with osteoporosis also had a greater time of evolution of the disease.

CONCLUSIONS

There is a decreased bone mass in lumbar spine and hip and a higher prevalence of osteoporosis in patients with cardiac failure before cardiac transplantation. Time of waiting for cardiac transplantation has been an important factor found in the development of metabolic bone disease in these patients.

Osteoporosis and lung transplantation: a prospective study

STUDY OBJECTIVE

Osteoporosis is a well-recognized complication of lung transplantation that may significantly impair the quality of life of transplant recipients. We performed a prospective study of bone mineral density (BMD) before and after transplantation to determine the degree of bone mass loss associated with lung transplantation Patients and design: We conducted a prospective study of BMD in 28 patients with various end-stage respiratory diseases pretransplantation and 6 to 12 months posttransplantation. The BMD of the lumbar spine (LS) and femoral neck (FN) were measured. All 28 patients were treated only with vitamin D and calcium supplementation posttransplant. The primary endpoint was the percentage change in BMD. The secondary endpoint was the incidence of fractures posttransplant. A univariate analysis was conducted to determine the various risk factors associated with bone mass loss pretransplant and posttransplant.

RESULTS

Prior to transplantation, moderate to severe bone disease was evident. The mean (+/- SD) pretransplant T score (the number of SDs from the peak bone mass) and Z score (the number of SDs from the age-matched mean) for the LS were -1.72 +/- 1.37 and -1.44 +/- 1.31, respectively. The mean pretransplant T score and Z score for the FN were -2.65 +/- 1.01 and -1.5 +/- 1.43, respectively. Within 6 to 12 months posttransplant, the mean BMD for the LS decreased by 4.76% (p < 0.001), while the mean BMD for the FN decreased by 5.3% (p < 0.001). Five of the 28 patients (18%) suffered osteoporotic fractures posttransplant, while no fractures were documented pretransplant. The cumulative steroid dose posttransplant was associated with a drop in BMD for the LS and FN (r = 0.39, p = 0.039 and r = 0.63, p < 0.001, respectively), while a negative association was found between cumulative steroid use pretransplant and baseline LS and FN T scores (r = -0.4, p = 0. 02 and r = -0.43, p = 0.023, respectively).

CONCLUSION

Within 6 to 12 months after lung transplantation, there is a significant decrease in BMD at both the LS and FN levels (approximately 5%) despite vitamin D and calcium supplementation. This drop in BMD is associated with a relatively high incidence of osteoporotic fractures posttransplant.

Bone densitometry should be included in the evaluation of candidates for lung transplantation

Bone loss and fractures are common complications of heart and liver transplantation, and are likely related to high-dose immunosuppressive therapy. We have previously demonstrated that many patients with end-stage lung disease already have osteoporosis and may be at even greater risk for fracture after lung transplantation. The purpose of this study is to determine the incidence of fracture in lung transplant recipients on osteoporosis prevention regimens, the relationship of fracture to pretransplant bone mineral density, and the impact of fracture on quality of life after lung transplantation. Twenty-one lung transplant candidates were prospectively evaluated with spine radiographs and bone mineral densitometry. Bone density was expressed as T scores, the number of standard deviations from the mean bone density of a young normal population of the same gender. Of 21 patients, 8 (38%) fractured during the first year. The mean pretransplant lumbar spine T score was significantly lower in the fracture patients (P = .03). Four of the 7 surviving fracture patients and 1 of the 10 patients who survived without fracture believed that chronic pain diminished their quality of life (X2 = 4.408; P = .04). These findings suggest that bone mineral density should be routinely included in the evaluation of lung transplant candidates. Patients with extremely low bone density or osteoporotic fracture should be counseled about the increased risk of fracture after transplantation.

Bone loss in long-term renal transplantation: histopathology and densitometry analysis

BACKGROUND

There is little information of the spectrum and factors implicated in the bone loss in long-term renal transplantation, and virtually no data using both histomorphometric and densitometric analysis.

METHODS

Twenty-three males and 22 females (13 postmenopausal) were studied with a bone biopsy and densitometry. Sixteen patients were on cyclosporine A monotherapy, 20 on azathioprine + prednisolone, and 9 on cyclosporine A + prednisolone or triple therapy. The mean time after transplantation was 127 +/- 70 months.

RESULTS

No group had a significant decrease in bone mineral density (BMD) of the axial skeleton compared with an age- and sex-matched normal population. Compared with sex-matched young controls, osteopenia was observed in all groups at the femoral neck (except premenopausal women and triple therapy) and in the triple-therapy group at the L1-L4 spine region. At the distal radius, osteopenia was found in all the groups. Histopathological diagnosis was mixed uremic osteodystrophy in 46.5%, adynamic bone in 23.2%, hyperparathyroid disease in 13.9%, and normal bone in 16.3%. The diagnosis was not different according to immunosuppressive therapy, but men tended to show more mixed uremic bone disease. There was no significant difference in BMD between histopathological subtypes. In general, patients showed slight osteoclast function increase, osteoblast function decrease, and marked retardation of dynamic parameters. The cyclosporine A monotherapy group had a significantly lower appositional rate than azathioprine + prednisolone. Men had a significantly lower bone volume than women, and premenopausal women had a significantly lower mineralizing surface than postmenopausal women and men. In the multivariate analysis, male gender, time after transplantation, old age, and time on dialysis prior to transplantation were significant predictive factors for a negative effect on bone mass.

CONCLUSIONS

Long-term renal transplant-patients showed reduced BMD in both trabecular and cortical bone. This reduction in BMD was not as severe as in short-term reports and was associated with osteoclast stimulation, osteoblast suppression, and retardation of mineral apposition and bone formation rates. Bone mass loss was not different between the immunosuppression therapy groups. Male gender and age were the strongest predictive factors for low bone mass.

Reduced bone mineral density in men after heart transplantation

Heart transplantation is associated with rapid bone loss and an increased prevalence and incidence of fractures. The aim of the present study was to compare the bone mineral density (BMD) of 30 heart transplant (HT) recipients to that of 31 chronic heart failure (CHF) patients waiting for transplantation and to determine their biochemical markers of bone resorption and hormone levels. The BMD of lumbar spine and proximal femur was determined by dual-energy X-ray absorptiometry. Anteroposterior and lateral radiographs of the thoracic and lumbar spine were also obtained. The mean age of the two groups did not differ significantly. Mean time of transplantation was 25.4 +/- 21.1 months (6 to 88 months). Except for the albumin levels, which were significantly higher, and magnesium levels, which were significantly lower in HT patients when compared to CHF patients, all other biochemical parameters and hormone levels were within the normal range and similar in the two groups. Both groups had lower BMD of the spine and proximal femur compared to young healthy adults. However, the mean BMD of HT patients was significantly lower than in CHF patients at all sites studied. Bone mass did not correlate with time after transplantation or cumulative dose of cyclosporine A. There was a negative correlation between BMD and the cumulative dose of prednisone. These data suggest that bone loss occurs in HT patients mainly due to the use of corticosteroids and that in 30% of the patients it can be present before transplantation. It seems that cyclosporine A may also play a role in this loss.

Mechanisms of bone loss following allogeneic and autologous hemopoietic stem cell transplantation

A significant proportion of patients will be long-term survivors of bone marrow transplantation (BMT) and little is known about their risk of late bony complications. We therefore evaluated bone mineral density (BMD) prior to BMT, post-transplantation changes in BMD, and mechanisms of bone loss in long-term survivors. We performed two analyses. The first was a cross-sectional study of 83 consecutive BMT patients (38 F, 45 M), examining the relationship between BMD and bone turnover, measured immediately prior to transplantation, and a number of disease and patient variables. The second was a prospective study of 39 patients (19F, 20 M) followed for a median of 30 months (range 5-64 months) following either allogeneic (allo, n = 29) or autologous (auto, n = 10) BMT to determine if bone loss was related to treatment of graft versus host disease (GVHD) with glucocorticoids and cyclosporine A, high bone turnover rates, or hypogonadism. Auto BMT recipients acted as a control group for effects of GVHD therapy on BMD. Prior to BMT, spinal and femoral neck (FN) BMDs were 8.6% and 14% lower in female auto BMT recipients than in female allo BMT recipients, respectively (p = 0.12 and p = 0. 003). Urinary bone resorption markers were higher than in normal gender- and age-matched control subjects. Patients treated previously with glucocorticoids also had 8% lower FN BMD. Glucocorticoid-pretreated women with amenorrhoea had lower lumbar spine (LS) and FN BMDs than eumenorrheic women and women receiving HRT. Post-allo BMT, patients lost 11.7% of FN BMD compared with a nonsignificant decrease of 1.1% post-auto BMT (p < 0.001). Spinal BMD and total body bone mineral content (TBBMC) decreased by 3.9% and 3.5%, respectively, post-allo, compared with an increase (1.5%, p = 0.03) or nonsignificant decrease (-3.7%, p = NS), respectively, post-auto BMT. Post-allo BMT bone loss correlated best with the cumulative prednisolone dose at the LS and FN, and with average daily prednisolone dose for TBBMC. At the spine, the rate of bone loss was 4%/10 g of prednisolone, while the rate of bone loss at the FN was greater (9%/10 g of prednisolone). Bone loss was also negatively related to the duration of cyclosporine therapy for GVHD and baseline deoxypyridinoline concentrations. Avascular necrosis of the femoral head occurred in four, and vertebral and rib fractures occurred in one of the allo BMT patients, but in no auto BMT patients. In conclusion, BMT recipients are at risk of osteoporosis secondary to bone loss associated with their underlying illness and/or chemotherapy, particularly in female autograft recipients, and in allograft recipients secondary to GVHD and its treatment.

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

OBJECTIVE

All patients attending the cardiac transplantation clinic at the Royal Perth Hospital were investigated to determine the prevalence of osteoporosis and to assess changes in bone metabolism and histomorphometry in a cohort of cardiac transplant recipients.

DESIGN

Retrospective cross-sectional study.

PATIENTS

Thirty-two patients (27 male; 5 female) who had received a cardiac transplant during the past 10 years and who were receiving immunosuppressive therapy with cyclosporin, azathioprine and prednisolone were studied.

MEASUREMENTS

All patients had bone densitometry by DEXA of the lumbar spine and femoral neck and X-rays of the thoracolumbar spine. Fasting serum ionized calcium, intact PTH, creatinine, 25 hydroxy-vitamin D, alkaline phosphatase, osteocalcin, testosterone and free thyroxine and urine calcium, creatinine, hydroxyproline and deoxypyridinoline were measured. Six osteoporotic patients consented to transiliac bone biopsy following double tetracycline labelling.

RESULTS

Osteoporosis was present at the lumbar spine in eight patients, femoral neck in seven patients and was present at one or more sites in 13 patients (41%). Seven patients (22%) had vertebral fractures which were asymptomatic in five patients. Secondary hyperparathyroidism was present in 16 patients (53%) but significant renal failure (creatinine clearance < 70 ml/min) was only found in 8 (50%). Levels of biochemical markers of bone turnover were increased in 23 patients (72%). Serum osteocalcin (P = 0.02) and alkaline phosphatase (P = 0.04) were significantly higher in osteoporotic patients than in nonosteoporotic patients. Histomorphometric findings varied markedly between patients. Microscopic features of hyperparathyroidism were not observed.

CONCLUSIONS

Osteoporosis and asymptomatic vertebral fractures are common following cardiac transplantation. Biochemical markers of bone turnover were increased in the majority of patients. Many had biochemical evidence of secondary hyperparathyroidism but this could be attributable to significant renal failure in only 50% of cases. Osteocalcin and alkaline phosphatase correlated inversely with bone density. Histomorphometric findings did not correlate with these biochemical changes in most cases. These results suggest that multiple factors are responsible for osteoporosis in cardiac transplant recipients. Osteocalcin and alkaline phosphatase may be useful biochemical markers, predicting patients at highest risk of fracture.

Increased risk of fracture in patients receiving solid organ transplants

The success of organ transplantation is related to advances in immunosuppressive therapy. These medications are associated with medical complications including bone damage. The objective of this study was to estimate and compare age, gender-specific fracture incidence between transplant recipients, and a large sample representative of the civilian noninstitutionalized United States population using the 1994 National Health Interview Survey (NHIS). This was a cohort study set in tertiary care centers. Five hundred and thirty-nine individuals who received abdominal organ and 61 heart transplants surviving at least 30 days at our institution from 1986 to 1996 were included in the study. Incident fractures were ascertained by mail, in-person interview, telephone survey, or medical record review. All fractures were verified. Organ-, age-, and gender-specific fracture numbers and rates and person-years of observation, were calculated for the transplant patients. Weighted age- and gender-specific fracture rates from the 1994 NHIS were applied to the number of person-years of observation for each organ-specific age and gender category of transplant patients to generate an expected number of fractures. The ratio of observed to expected number of fractures was used to compare fracture experience of transplant patients to that of the national sample from the 1994 NHIS. Fifty-six of 600 (9.3%) patients had at least one fracture following 1221 person-years of observation. The sites of initial symptomatic fracture were as follows: foot (n = 22), arm (n = 8), leg (n = 7), ribs (n = 6), hip (n = 4), spine (n = 3), fingers (n = 3), pelvis (n = 2), and wrist (n = 1). Fracture incidence was 13 times higher than expected in male heart recipients age 45-64 years; nearly 5 times higher in male kidney recipients age 25-44 and age 45-64 years; and 18 times and 34 times higher in female kidney recipients age 25-44 years and 45-64 years compared with NHIS data. We have shown an increased incidence of fractures and estimated the magnitude of this problem in patients undergoing solid organ transplantation. Our work defines the need for a long-term prospective study of fracture risk in these patients.

High turnover bone disease following lung transplantation

Recipients of lung transplants are at very high risk for significant bone loss. Nevertheless, data on bone disease after lung transplantation are still limited. We, therefore, retrospectively evaluated the data of 33 patients surviving at least 1 year after lung transplantation (LTx) who were seen in our outpatient clinic for osteologic evaluation. Results of clinical evaluations, radiographs, and dual-energy X-ray absorptiometry (DXA) were related to each other, to clinical variables, and to serum levels of osteocalcin, parathyroid hormone (PTH), and 25-hydroxyvitamin D: 14 of 33 patients (42%) had vertebral fractures, 9 of whom were diagnosed within 2 years after transplantation. Bone mineral density values (DXA) were markedly decreased and predictive of compression fractures. 25-Hydroxyvitamin D levels were low in 13 patients (39%) and PTH was elevated in 7 (21%). Despite corticosteroids and low 25-hydroxyvitamin D, serum osteocalcin was elevated in 12 patients (36%). This was only partially explained by hyperparathyroidism, low sex hormones, and impaired renal function, and may partly be caused by cyclosporin A. We thus conclude that severe symptomatic bone disease is common in lung transplant recipients and due to a complex situation including high turnover bone loss and hypovitaminosis D. DXA can be used to estimate fracture risk for individual patients.

Exercise training in patients with CHF and heart transplant recipients

The number of chronic heart failure (CHF) patients and heart transplantation (HT) recipients enrolled in rehabilitation and maintenance exercise programs continues to expand. There is growing clinical consensus that stable patients with CHF respond favorably to exercise training and convincing evidence that exercise training should be an essential adjunct therapy in postoperative management of HT recipients. This review examines the following specific advances in exercise physiology for heart failure and heart transplantation patients: 1) the mechanisms of exercise intolerance in CHF and the results of exercise rehabilitation studies in these patients; 2) the exercise challenges conferred by glucocorticoid therapy and chronic cardiac denervation in HT recipients; and 3) a summary of current recommendations and guidelines for exercise prescription in each patient population.

The fate of bone after renal transplantation

Post-renal-transplantation bone disease is a well known entity. Immunosuppressive agents and persistence of hyperparathyroidism have primarily been implicated in its etiology. Renal transplantation patients are unique in that the bone changes occur on a background of pre-existing renal osteodystrophy. This review focuses on post-renal-transplantation bone disease. Unfortunately, the existing data in the review period, besides being scanty, provide conflicting information. This is due to the diversity of immunosuppressive regimens employed, the patient populations studied, diagnostic tools and criteria used by different centers, and the lack of formal trials.

Effects of orthotopic liver transplantation on body composition

AIMS/BACKGROUND

The effects of orthotopic liver transplantation on body composition are unclear. We aimed to assess changes in body composition after transplantation using dual energy x-ray absorptiometry and total body potassium.

METHODS

Dual energy x-ray absorptiometry and total body potassium counting to assess muscle mass were performed in 55 patients before and up to 24 months after liver transplantation and the results expressed as paired data before and at time intervals after transplantation.

RESULTS

The results showed that total body weight fell by 3.6 +/- 1.3 kg (p < 0.02) at 1 month, with a maximal fall in lean tissue mass at 2-5 months of 4.8 +/- 1.2 kg (p < 0.003). Thereafter, no change in lean tissue mass was recorded, although there were increases at 12 and 24 months of total body weight (11.5 +/- 2.4 kg, 7.8 +/- 3.1 kg; p < 0.03, respectively) and fat mass (12.9 +/- 2.2 and 10.5 +/- 2.7 kg; p < 0.003). A fall in total body potassium was seen at 1 month (118 +/- 12 mmol; p < 0.003) and 2-5 months (176 +/- 9.9 mmol; p < 0.03), which mirrored the fall in lean mass.

CONCLUSIONS

After liver transplantation there is an initial fall in body weight due to a loss of lean mass. Lean mass does not recover after transplantation, although there is an increase in fat mass that leads to the observed increase in total body weight.

The science and therapy of glucocorticoid-induced bone loss

Glucocorticoids are critical in the management of chronic, noninfectious, inflammatory diseases. Bone loss is a most devastating side effect of these powerful medications. Glucocorticoids produce bone loss by altering calcium metabolism, suppressing gonadal hormone production, and inhibiting bone formation. Now that the mechanism of glucocorticoid-induced bone loss is understood and effective medications are available, this disease can be prevented and reversed.

Osteoporosis after organ transplantation

Within the past 2 decades, organ transplantation has become established as effective therapy for endstage renal, hepatic, cardiac, and pulmonary disease. Regimens to prevent rejection after transplantation commonly include high-dose glucocorticoids and calcineurin-calmodulin phosphatase inhibitors (the cyclosporines and tacrolimus), which are detrimental to bone and mineral homeostasis, and are associated with rapid bone loss that is often superimposed upon an already compromised skeleton. The incidence of fracture ranges from 8% to 65% during the first year after transplantation. In general, fracture rates are lowest in renal transplant recipients and highest in patients who receive a liver transplant for primary biliary cirrhosis. Rates of bone loss and fracture are greatest during the first 6 to 12 months after transplantation. Postmenopausal women and hypogonadal men appear to be at increased risk. Although no pretransplant densitometric or biochemical parameter has yet been identified that adequately predicts fracture risk in the individual patient, low pretransplant bone mineral density does tend to increase the risk of fracture, particularly in women. However, patients may sustain fractures despite normal pretransplant bone mineral density. Although the pathogenesis of the rapid bone loss is multifactorial, prospective biochemical data suggest that uncoupling of bone formation from resorption may be in part responsible, at least during the first 3 to 6 months. Prevention of transplantation osteoporosis should begin well before transplantation. Patients awaiting transplantation should be evaluated with spine radiographs, bone densitometry, thyroid function tests, serum calcium, vitamin D, parathyroid hormone, and testosterone (in men). Therapy for osteoporosis, low bone mass, and potentially reversible biochemical causes of bone loss should be instituted during the waiting period before transplantation. In patients with normal pretransplant bone density, therapy to prevent early posttransplant bone loss should be instituted immediately following transplantation. Most pharmacologic agents available for therapy of osteoporosis have not been subject to prospective controlled studies in organ transplant recipients. However, antiresorptive drugs, such as biphosphonates, appear to hold therapeutic promise.

Mechanisms of bone loss after cardiac transplantation

To determine the mechanism of bone loss after cardiac transplantation (CTX), we studied 50 men 0.5-47 months after CTX (ages 18-64 years) who received prednisolone and cyclosporin to prevent rejection, and 40 healthy men as controls (ages 20-70 years). We measured bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA), bone resorption using urinary cross-linked N-terminal telopepides of type I collagen (NTx), and bone formation using osteocalcin (BGP) and bone alkaline phosphatase (BAP). The results from the controls were used to calculate z scores. BMD was significantly decreased at the lumbar spine, femoral neck, and total body, and bone turnover was significantly increased as assessed by NTx/creatinine, BGP, and BAP as compared with controls (p < 0.01 for all measurements). To evaluate the cause of the increased bone turnover we measured serum parathyroid hormone (PTH) by IRMA, and this was also elevated (p < 0.001). There was a significant correlation between serum PTH and BGP (r = 0.58, p < 0.01). To evaluate the cause of the increase in PTH, we measured serum calcium and it was decreased (p < 0.001), serum phosphorus was increased (p < 0.001), serum creatinine was increased (p < 0.001), and serum 1,25-dihydroxyvitamin D3 [1,25(OH)2D, RIA] was decreased (p = 0.03). Serum PTH correlated weakly with serum calcium (r = -0.41, p < 0.003) and with serum creatinine (r = 0.35, p = 0.01). There was a weak, but significant, correlation between serum creatinine and 1,25(OH)2D3 (r = 0.33, p = 0.03). Serum levels of testosterone and dehydroapiandrosterone sulfate were decreased after CTX but did not correlate with any other parameters. There was a weak negative correlation between prednisolone daily dose and serum BGP level (r = 0.29, p = 0.06) in those patients whose prednisolone current dose was >7.5 mg/day. We conclude that: (1) the low BMD found after CTX is associated with increased bone turnover which results, in turn, from renal impairment; (2) prednisolone is involved in rapid bone loss, whereas mild secondary hyperparathyroidism may be a major contributor to disorder of bone remodeling after this rapid loss; and (3) decreased androgen levels may not be a major factor resulting in bone loss in men after CTX.

Management of the cardiac transplant recipient: roles of the transplant cardiologist and primary care physician

Cardiac transplantation has become an accepted treatment for selected patients with end-stage heart failure. Despite a successful transplant, denervated transplanted hearts respond differently to cardiac drugs than nontransplanted hearts. The treatments for bradycardia, tachycardia, and hypotension are different than for nontransplanted hearts. Despite the improvement in long-term survival, a number of complications may occur posttransplantation. These complications include, allograft rejection, infection, allograft coronary artery disease, and malignancy. Additionally, posttransplant patients may have complications from the immunosuppressive agents cyclosporine, prednisione, and azathioprine. Such complications include drug interactions with commonly prescribed medications, hypertension, hyperlipidemia, osteoporosis, and gastrointestinal complications. The purpose of this article is to discuss the management of the cardiac transplant recipient as it relates to the aforementioned complications. Management of the cardiac transplantation patient by the primary care physician will also be discussed, including indications for consultation by the primary care physician with the transplant center.

Alendronate prevents cyclosporin A-induced osteopenia in the rat

Post-transplantation bone disease is an increasingly recognized clinical entity whose etiology is multifactorial. The immunosuppressant agent cyclosporine-A (CsA) has repeatedly been shown experimentally to induce a high-turnover osteopenic state. Alendronate (Alen.) is a new generation bisphosphonate having far greater antiresorptive potency than previous bisphosphonates. It inhibits osteoclast resorption in vitro and in vivo without adversely affecting bone mineralization. This study was designed to investigate whether alendronate could prevent CsA-induced osteopenia in the rat. Forty-eight 8-month-old male Sprague Dawley rats were randomized into four groups to receive the following for 28 days: (1) CsA vehicle (veh.) p.o. daily and alendronate vehicle subcutaneously (s.c.) twice/week, (2) CsA 15 mg/kg p.o. daily and Alen. veh. s.c. twice/week, (3) Alen. 70 micrograms/kg s.c. twice/ week and CsA veh. p.o. daily, and (4) CsA 15 mg/kg p.o. daily and Alen. 70 micrograms/kg s.c. twice/week. Rats were weighed and bled and serum was assayed serially for calcium, PTH, 1,25(OH)2vit.D, and osteocalcin. Tibiae were removed following sacrifice on day 28, after double demeclocycline and calcein labeling, for histomorphometric analysis. Treated groups were compared to the vehicle-treated control. We confirmed previous findings that CsA produces elevated 1,25(OH)2 vitamin D and serum osteocalcin levels. Alendronate treatment by itself decreased osteocalcin by day 28 and resulted in a marginal decrease in serum total calcium on day 14. The histomorphometry findings reconfirmed that the administration of CsA induces a state of high-turnover osteopenia. Alendronate prevented CsA's adverse effects, particularly in maintaining trabecular bone volume, presumably by decreasing bone remodeling. Alendronate would seem to hold therapeutic promise in post-transplantation bone disease.

Nonpulmonary medical complications in the intermediate and long-term survivor

This article deals with the nonpulmonary, non-infectious complications in intermediate and long-term survivors of lung transplantation. Although they are an infrequent cause of mortality, these disorders can cause significant morbidity in this population. Diseases associated with the gamut of medications used post-transplant are specifically discussed, as are diseases caused by the direct immunosuppressive action of some of these drugs. General care of transplant patients also entails attention to their underlying diseases, and to routine medical considerations common to all patients.

Secondary osteoporosis

Secondary osteoporosis is diagnosed when there is a well-established disease-related risk factor for fracture or low bone mass. Secondary osteoporosis is associated with a substantial minority of osteoporotic fractures in women perhaps with a majority of osteoporotic related fractures in men. This chapter does not review all the possible causes of low bone mass and fractures but picks out some of the more important causes of, with an emphasis on the main iatrogenic cause, that is corticosteroid induced osteoporosis. It also highlights some of the possible causes which could be avoidable. Where appropriate the methods of prevention and treatment of secondary osteoporosis are reviewed.

The role of testosterone in cyclosporine-induced osteopenia

Our laboratory has demonstrated that the immunosuppressants Cyclosporin A (CsA) and tacrolimus (FK506), in vivo in the rat, produce a high-turnover osteopenia. CsA is known to decrease serum testosterone (Test) levels both in the rat and in human transplant patients. Less is known of FK506's effect on androgens. CsA-induced hypogonadism may contribute to the aforementioned bone loss because hypogonadism itself is a risk factor for osteoporosis and fracture. The aim of this study was to assess serum androgen levels following CsA and FK506 therapy and to see wether Test replacement therapy, in the form of 28-day controlled release subcutaneous pellet implants, could prevent CsA-induced osteopenia. Two experiments were conducted. In experiment I, four groups of 6-month-old male Sprague-Dawley rats received the following: (A) CsA vehicle and placebo pellet, (B) Test 15 mg pellet and CsA vehicle, (C) CsA 10 mg/kg and placebo pellet, (D) Test 15 mg pellet and CsA 10 mg/kg. In experiment II, two groups of rats received (E) FK506 vehicle and (F) FK506 4 mg/kg. CsA, FK506, and vehicles were given for 28 days by daily oral gavage. The rats were weighted and bled on days 0, 14, and 28. All rats received double fluorescent labeling, and on day 28 the tibiae were removed for histomorphometry. Whole blood was assayed for CsA and FK506 levels. Serum was assayed for total and free Test as well as for osteocalcin (BGP), blood urea nitrogen (BUN), creatinine, and calcium. Whole blood monoclonal CsA levels measured by fluorescent immunoassay were in the therapeutic range, while a drug concentration profile showed good absorption of FK506. Those rats receiving Test and FK506 lost weight, while those receiving CsA remained constant. BUN was only marginally elevated in the CsA-treated groups on day 28 (p < 0.05), while creatinine was unchanged. On day 28, total and free Test was significantly reduced in the CsA-treated rats versus control (p < 0.05), while Test replacement therapy maintained total Test levels above vehicle (p < 0.01) and free Test levels similar to vehicle on day 28. FK506 did not lower total or free Test levels. BGP levels were significantly increased in the CsA (p < 0.01) and FK506 (p < 0.001) groups on day 28. BGP in the groups receiving Test alone and in combination with CsA remained similar to vehicle. Histomorphometry confirmed CsA- and FK506-induced high-turnover osteopenia. The Test alone group marignally increased bone formation. Test replacement failed to prevent the CsA-induced bone loss. In conclusion, immunosuppressive doses of CsA, but not FK506, lowers serum total and free Test. Hypoandrogenemia does not seem to be a major factor in CsA-induced osteopenia because bone loss occurs despite Test replacement.

Trauma management in solid organ transplant recipients

With trauma being common in this country and over 110,000 recent organ transplants performed, transplant recipients may become trauma victims. At present, only a few older small series of traumatized transplant patients exist. At the University of Arkansas, over the past 40 months, 12 patients with significant trauma were retrospectively identified (seven with kidney and five with combined kidney and pancreas transplants). The most common causes of trauma were car accidents and falls. All patients suffered closed skeletal fractures, and no transplanted organs were directly injured or lost. Complications included death, deep vein thrombosis, renal failure, sepsis, and pneumonia. In spite of immunosuppression and preexisting renal osteodystrophy, fractures in the surviving patients healed, with a mean follow-up of 15 months. A large series of traumatized transplant patients is presented with a review of the management of traumatic injuries for each type of organ transplant. A trauma transplant registry is needed to formulate appropriate management and follow-up.