Early increase in plasma parathyroid hormone levels following liver transplantation

Bone disease following solid organ transplantation: A narrative review and recommendations for management from The European Calcified Tissue Society

INTRODUCTION

Solid organ transplantation is an established therapy for end-stage organ failure. Both pre-transplantation bone disease and immunosuppressive regimens result in rapid bone loss and increased fracture rates.

METHODS

The European Calcified Tissue Society (ECTS) formed a working group to perform a systematic review of existing literature on the consequences of end-stage kidney, liver, heart, and lung disease on bone health. Moreover, we assessed the characteristics of post-transplant bone disease and the skeletal effects of immunosuppressive agents and aimed to provide recommendations for the prevention and treatment of transplantation-related osteoporosis.

RESULTS

Characteristics of bone disease may differ depending on the organ that fails, but patients awaiting solid organ transplantation frequently depict a wide spectrum of bone and mineral abnormalities. Common features are a decreased bone mass and impaired bone strength with consequent high fracture risk, all of which are aggravated in the early post-transplantation period.

CONCLUSION

Both the underlying disease leading to end-stage organ failure and the immunosuppression regimens implemented after successful organ transplantation have detrimental effects on bone mass, quality and strength. Given existing ample data confirming the high frequency of bone disease in patients awaiting solid organ transplantation, we recommend that all transplant candidates should be assessed for osteoporosis and fracture risk and, if indicated, treated before and after transplantation. Since bone loss in the early post-transplantation period occurs in virtually all solid organ recipients and is associated with glucocorticoid administration, the goal should be to use the lowest possible dose and to taper and withdraw glucocorticoids as early as possible.

Ciclosporin therapy is associated with minimal changes in calcium metabolism in dogs with atopic dermatitis

BACKGROUND

Ciclosporin is widely used in the management of canine atopic dermatitis. In humans, ciclosporin therapy has been linked to disturbances in calcium metabolism and resultant skeletal disorders.

OBJECTIVES

The objective of this study was to assess calcium homeostasis in dogs before and after a 6 week course of once daily oral ciclosporin at the licensed dose (5 mg/kg).

ANIMALS

Sixteen client-owned dogs with spontaneous atopic dermatitis.

METHODS

Serum concentrations of calcium, phosphate, creatinine, 25-hydroxyvitamin D, 1,25-dihyroxyvitamin D and plasma concentrations of ionized calcium and parathyroid hormone (PTH) were measured, together with the urinary fractional excretion of calcium and phosphate. The extent of skin lesions was scored using the Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03 and the degree of pruritus by the Edinburgh Pruritus Scale prior to and at the end of the study.

RESULTS

The CADESI-03 and the Edinburgh Pruritus Scale scores decreased satisfactorily in all dogs by the end of the study. Plasma PTH concentrations were significantly increased (P = 0.02) following ciclosporin treatment, whereas all other biochemical parameters were not significantly different from their starting values. The increase in PTH was mild in most cases and the proportion of dogs that had a PTH concentration above the reference range was not significantly different following treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study indicates that ciclosporin has minimal impact on calcium metabolism in dogs with atopic dermatitis when used at the licensed and clinically effective dosage for 6 weeks.

Changes in vitamin D binding protein and vitamin D concentrations associated with liver transplantation

BACKGROUND

Vitamin D deficiency is associated with fractures, infections and death. Liver disease impairs vitamin D and vitamin D binding protein (DBP) metabolism.

AIMS

We aimed to determine the impact of liver transplantation on vitamin D, particularly on DBP and free vitamin D concentrations.

METHODS

Serum 25(OH)D, 1,25(OH)(2) D and DBP concentrations were measured in 202 adults before liver transplantation and 3 months later in 155. Free vitamin D concentrations were estimated from these values. Risk factors for 25(OH)D deficiency (<20 ng/ml) and low 1,25(OH)(2) D (<20 pg/ml) were examined with logistic regression, and changes in concentrations following transplantation with linear regression.

RESULTS

Pretransplant, 84% were 25(OH)D deficient, 13% had 25(OH)D concentrations <2.5 ng/ml, and 77% had low 1,25(OH)(2) D. Model for end-stage liver disease score ≥ 20 (P < 0.005) and hypoalbuminemia (P < 0.005) were associated with low 25(OH)D and 1,25(OH)(2) D concentrations. Following transplantation, 25(OH)D concentrations increased a median of 17.8 ng/ml (P < 0.001). Albumin increased from a median of 2.7 to 3.8 g/dl (P < 0.001) and DBP from 8.6 to 23.8 mg/dl (P < 0.001). Changes in total 25(OH)D were positively and independently associated with changes in DBP (P < 0.05) and albumin (P < 0.001). Free 25(OH)D concentrations rose from 6.0 to 9.7 pg/ml (P < 0.001). In contrast, total 1,25(OH)(2)D concentrations rose only by 4.3 pg/ml (P < 0.001) and free 1,25(OH)(2D concentrations declined (P < 0.001).

CONCLUSIONS

Serum total and free 25(OH)D and DBP concentrations rose substantially following transplantation, while 1,25(OH)(2) D concentrations showed modest changes and free 1,25(OH)(2) D decreased. Studies of the effects of vitamin D status on diverse transplant complications are needed.

Vitamin D in organ transplantation

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

Alveolar bone loss in liver transplantation patients: relationship with prolonged steroid treatment and parathyroid hormone levels

AIM

To evaluate the relationship among alveolar bone loss (ABL), bone status and calcium-regulating hormones in liver transplantees.

PATIENTS AND METHODS

Twenty-one liver transplantees underwent a full oral examination. The correlations among bone densitometry, bone metabolic status and drug treatment were examined.

RESULTS

Twelve patients had osteopenia, and six were osteoporotic. ABL was 4.33+/-2.32 mm (range 0.67-9.92). Parathyroid hormone (PTH) levels ranged from 14 to 106 (mean 55.2+/-26.4). The mean 25(OH)D(3) was 11.68+/-4.7, range 3.5-21.1 ng/ml. Nine patients were vitamin D deficient (<10 ng/ml); none of the patients had 25(OH)D(3) levels > or =30 ng/ml. No correlation was found between ABL and current or total glucocorticoids dose, although there was an inverse relation with the duration of treatment (r =-0.474, p=0.03). A positive correlation was found between ABL, PTH (r =0.419, p=0.059) and hip bone mineral density (BMD) (r=0.482, p=0.027). ABL correlated closely with age, PTH, glucocorticoid treatment (duration) and hip BMD (r =0.810, p=0.004).

CONCLUSIONS

The majority of liver transplant patients had insufficient 25(OH)D(3) serum levels. Changes in calcium-regulating hormones and hip BMD were correlated with ABL. Therefore, therapeutic intervention aimed at treating vitamin D deficiency and secondary hyperparathyroidism should be considered in these patients. The benefits of vitamin D treatment in the management of secondary hyperparathyroidism and possible decrease in ABL deserve further evaluation in controlled trials.

Vitamin D and parathyroid hormone in outpatients with noncholestatic chronic liver disease

BACKGROUND & AIMS

The liver plays a central role in vitamin D metabolism. Our aim was to determine the prevalence and type of vitamin D-parathyroid hormone (PTH) disturbance in ambulatory patients with noncholestatic chronic liver disease (CLD) and its relationship with disease severity and liver function.

METHODS

We studied 100 consecutive outpatients (63 men, 37 women; mean age, 49.0 +/- 12.1 [SD] y) with noncholestatic CLD caused by alcohol (n = 40), hepatitis C (n = 38), hepatitis B (n = 12), autoimmune hepatitis (n = 4), hemochromatosis (n = 4), and nonalcoholic steatohepatitis (n = 2); 51 patients had cirrhosis. Serum concentrations of 25-hydroxyvitamin D (25[OH]D), PTH, calcium, phosphate, magnesium, creatinine, and liver function tests were determined.

RESULTS

Serum 25(OH)D levels were inadequate in 91 patients: vitamin D deficiency (<50 nmol/L) was found in 68 patients and vitamin D insufficiency (50-80 nmol/L) was found in 23 patients. Secondary hyperparathyroidism (serum PTH, >6.8 pmol/L) was present in 16 patients. The prevalence of vitamin D deficiency was significantly higher in cirrhotic vs noncirrhotic patients (86.3% vs 49.0%; P = .0001). In Child-Pugh class C patients, 25(OH)D levels were significantly lower than in class A patients (22.7 +/- 10.0 nmol/L vs 45.8 +/- 16.8 nmol/L; P < .001). Serum 25(OH)D independently correlated with international normalized ratio (negatively; P = .018) and serum albumin (positively; P = .007). Serum 25(OH)D levels of less than 25 nmol/L predicted coagulopathy, hyperbilirubinemia, hypoalbuminemia, increased alkaline phosphatase, and anemia and thrombocytopenia.

CONCLUSIONS

Vitamin D inadequacy is common in noncholestatic CLD and correlates with disease severity, but secondary hyperparathyroidism is relatively infrequent. Management of CLD should include assessment of vitamin D status in all patients and replacement when necessary.

Bone mineral density before and after OLT: long-term follow-up and predictive factors

Fracturing after liver transplantation (OLT) occurs due to the combination of preexisting low bone mineral density (BMD) and early posttransplant bone loss, the risk factors for which are poorly defined. The prevalence and predictive factors for hepatic osteopenia and osteoporosis, posttransplant bone loss, and subsequent bone gain were studied by the long-term posttransplant follow-up of 360 consecutive adult patients with end-stage primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Only 20% of patients with advanced PBC or PSC have normal bone mass. Risk factors for low spinal BMD are low body mass index, older age, postmenopausal status, muscle wasting, high alkaline phosphatase and low serum albumin. A high rate of spinal bone loss occurred in the first 4 posttransplant months (annual rate of 16%) especially in those with younger age, PSC, higher pretransplant bone density, no inflammatory bowel disease, shorter duration of liver disease, current smoking, and ongoing cholestasis at 4 months. Factors favoring spinal bone gain from 4 to 24 months after transplantation were lower baseline and/or 4-month bone density, premenopausal status, lower cumulative glucocorticoids, no ongoing cholestasis, and higher levels of vitamin D and parathyroid hormone. Bone mass therefore improves most in patients with lowest pretransplant BMD who undergo successful transplantation with normal hepatic function and improved gonadal and nutritional status. Patients transplanted most recently have improved bone mass before OLT, and although bone loss still occurs early after OLT, these patients also have a greater recovery in BMD over the years following OLT.

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.

High-turnover osteoporosis is induced by cyclosporin A in rats

Cyclosporin A (CsA) is used widely as an immunosuppressive agent, but it induces osteoporosis as a prominent side effect. To elucidate the mechanisms involved in CsA-induced osteoporosis, the effects of CsA on bone metabolism were investigated in a rat experimental model. Fifteen-day-old rats were fed a powdered diet containing or lacking CsA for 8-30 days. Analysis was performed by micro-computed tomography (muCT) and light microscopy to examine histomorphometric changes in rat tibiae on days 8, 16, and 30. Plasma parathyroid hormone (PTH) and osteocalcin (OCN) levels were determined by enzyme-linked immunosorbent assay (ELISA) on days 8, 16, and 30. The expression of OCN, osteopontin (OPN), and cathepsin K mRNAs in tibial bone marrow was examined by Northern blot analysis on days 8 and 16. Although no significant differences were observed in tibial length during the experimental periods, or in histomorphometric parameters on day 8, an apparent decrease in bone volume was observed in the CsA-treated group after day 16. Histologic analysis showed that the number of osteoblasts and osteoclasts on the surface of trabecular bone in the CsA-treated group had increased significantly on day 16. Plasma PTH and OCN levels in CsA-treated rats were significantly higher than those in control animals on day 8. Northern blot analysis revealed that the CsA-treated group showed an increase in the expression of OCN, OPN, and cathepsin K mRNAs on day 8 compared with the controls. These findings suggest that bone resorption in CsA-treated rats is induced by high-turnover osteoporosis and that bone remodeling activity may be activated by PTH.

Older age and liver transplantation: a review

Patients older than 60 are undergoing transplantation with increasing frequency. Reports from several transplant centers document that overall short-term patient survival rates in seniors undergoing liver transplantation are comparable to survival rates of younger adults. However, specific subgroups of older patients may not fare as well. Seniors with far-advanced end-stage liver disease are high-risk for liver transplantation and have poor survival rates. In addition, seniors older than 65 have worse outcomes than those who are 60 to 65, and studies have shown increased mortality with increasing age as a continuous variable. On the other hand, the majority of seniors who survive liver transplantation have full or only minimally limited functional status. Preoperative evaluation of older patients for transplantation requires careful screening to exclude cardiopulmonary disease, malignancy, and other diseases of the aged. Paradoxically, seniors may benefit from a senescent immune system, which results in decreased requirements for immunosuppressive drugs, and possibly a lower rate of acute allograft rejection. Despite good overall short-term survival in the elderly, long-term survival may be worse because of an increased rate of long-term complications, such as malignancy and heart disease. In conclusion, although advanced age is a negative risk factor, advanced age alone should not exclude a patient from liver transplantation; however, it mandates thorough pretransplant evaluation and careful long-term follow-up with attention to usual health maintenance issues in the elderly.

Immunosuppressive and postoperative effects of orthotopic liver transplantation on bone metabolism

Bone loss occurs early after orthotopic liver transplantation (OLT) in all liver transplant recipients and leads to postoperative fractures, especially in cholestatic patients with the lowest bone mass. Little is known about the underlying changes in bone metabolism after OLT or about the etiology of these changes. Histomorphometric analysis of bone biopsies, a method that allows assessment of bone volume, resorption, and formation, has shown improved bone metabolism at 4 months after OLT. It has further suggested that accelerated posttransplant bone loss occurs in the first 1-2 months after OLT, probably by an additional insult to bone formation. This study attempts to correlate the histomorphometric bone changes in paired bone biopsies (OLT and 4 months after OLT) of 33 patients undergoing OLT for chronic cholestatic liver disease with the many clinical and biochemical changes in these patients over the same period. Cumulative steroid dosage early after OLT is shown to be important, presumably by decreasing bone formation rates. The actual effect of calcineurin inhibitors on this early phase of bone loss is less clear, although posttransplant histomorphometric findings suggest that tacrolimus-treated patients have an earlier recovery of bone metabolism and trabecular structure compared with cyclosporine patients. Other factors important in the recovery of bone metabolism after the early phase of bone loss are recovery of liver and gonadal function and better calcium balance.

Bone histomorphometric changes after liver transplantation for chronic cholestatic liver disease

Thirty-three patients with cholestatic liver disease underwent histomorphometric assessment of paired bone biopsy specimens at time of orthotopic liver transplantation (OLT) and 4 months thereafter. At 4 months after OLT, bone metabolism improved, with bone formation increasing to normal and no change in bone resorption. Early post-transplant bone loss may be attributed to an additional insult to bone formation early after transplantation.

INTRODUCTION

Patients with advanced liver disease, especially chronic cholestasis, often have osteopenia, which worsens early after orthotopic liver transplantation (OLT) before starting to recover. The changes in bone metabolism leading to this rapid loss of bone after OLT, and to its recovery, are poorly defined.

MATERIALS AND METHODS

In thirty-three patients with advanced chronic cholestatic liver disease, tetracycline-labeled bone biopsy specimens were analyzed prospectively at time of OLT and at 4 months after OLT, as part of a randomized trial to study the efficacy of calcitonin on post-transplant bone loss. Hierarchical cluster analysis of histomorphometric parameters was performed in an attempt to establish the functional grouping of individual histomorphometric parameters before and after OLT.

RESULTS AND CONCLUSIONS

Results showed that from the time of OLT to 4 months after OLT, bone mineral density of the lumbar spine and histomorphometric parameters of bone volume decreased, consistent with early post-transplant bone loss. Histomorphometric resorption parameters were increased before OLT, with no change after OLT. Histomorphometric formation parameters increased from low values before OLT to normal values at 4 months after OLT, with the exception of mean wall thickness values, which further decreased after OLT, suggesting an additional insult to bone formation during the study period. Histomorphometric changes after OLT were similar in female and male patients, pre- and postmenopausal women, and in patients treated and not treated with calcitonin. Hierarchical cluster analysis suggested that before OLT, bone resorption was functioning independently of bone formation, but that by 4 months after OLT, their coupled relationship had improved. Therefore, despite post-transplant bone loss, by 4 months after OLT, bone metabolism had improved, with increased bone formation and more coupled bone balance, as suggested by hierarchical cluster analysis.

Osteoporosis after liver transplantation

Osteoporosis remains a serious potential complication of liver transplantation, although its incidence may be significantly reduced by the use of lower doses of glucocorticoids. Additional factors likely to contribute to its pathogenesis include other immunosuppressive agents, particularly cyclosporin A and FK506, vitamin D insufficiency, secondary hyperparathyroidism, hypogonadism and pre-existing bone disease. Bone density assessment and spinal X-rays should be performed before transplantation to assess subsequent fracture risk and vitamin D and gonadal status assessed. Measures should be taken to optimise bone health prior to transplantation; in those with low bone mineral density and/or previous fragility fracture, prophylaxis against bone loss after transplantation should be considered. Although anti-fracture efficacy has not been established for any agent there is evidence, mainly in patients undergoing other forms of solid organ transplantation, that repeated infusions of pamidronate may be effective in preventing bone loss.

Predominant factors associated with bone loss in liver transplant patients - after prolonged post-transplantation period

INTRODUCTION

Osteoporosis is a major cause of morbidity in liver transplant recipients and is associated with multiple factors.

OBJECTIVES

To evaluate bone mineral density (BMD), bone turnover and calcium-regulating hormones in 29 patients (17 men, 12 women) 2-12 yrs following liver transplantation for non-alcoholic liver diseases.

RESULTS

Fifteen patients (52%) were on immunosuppressive treatment with tacrolimus and 14 (48%) with cyclosporine. Eleven patients (38%) were currently on prednisone, 18 patients (62%) had stopped glucocorticoid treatment 6 months to 11 yrs prior to the study. Nineteen patients (65.5%) had decreased BMD according to WHO criteria, 17 (58.2%) at the femoral neck, 13 (44.8%) at the lumbar spine. Nineteen patients (65.5%) had a subnormal (<15 ng/mL) serum level of 25 (OH) D3. These patients had significantly lower BMD at the femoral neck (p = 0.02). Femoral neck BMD negatively correlated with serum parathyroid hormone level (p = 0.06, r = -0.35), length of the post-transplantation period (p = 0.025, r = -0.416) and duration of glucocorticoid treatment (p = 0.029, r = -0.406), regardless of its cumulative dose. Symptomatic fractures were less frequent in tacrolimus treated patients than in cyclosporine users (p = 0.03).

CONCLUSIONS

Decreased BMD is frequent following liver transplantation and is affected by vitamin D deficiency, cyclosporine use, and the duration of glucocorticoid therapy, but not by its cumulative dose. Achievement and maintenance of optimal vitamin D status and shortening of glucocorticoid treatment period may have a favorable effect on bone preservation.

Psychosomatic interrelations following liver transplantation

It is well described that quality of life (QoL) improved after liver transplantation. The aim of the present study was to investigate how psychosocial parameters develop after liver transplantation (LTX) and whether post-operative complaints are the result of osteoporosis or patient somatization. The prospective study looks into biomedical and psychosocial parameters of 82 LTX patients before, 1 and 3 yrs after transplantation. Osteoporosis was measured by bone mineral density (BMD) and psychosocial parameters were assessed with validated questionnaires measuring complaints, mood and overall QoL. Overall QoL and mood improved after liver transplantation, while back and limb pain increased continuously. Back and limb pain were highly correlated with reduced bone density and high values for tiredness and depressive anxiety. Back and limb pain of patients following liver transplantation may indicate the development of a post-operative depression in some cases. The treatment offered by an essentially biologically based medicine may promote the manifestation of this depression as a somatization disorder.

Bone mineral density and height gain in children with chronic cholestatic liver disease undergoing transplantation

BACKGROUND

Osteodystrophy is a well-described complication of chronic liver disease. Previous reports in adults and children undergoing liver transplantation (LT) were discordant, with the former showing no improvement of bone disease in the first year after transplantation and the latter demonstrating remarkable benefit from it. Our aim was to perform a pilot study on osteodystrophy in children undergoing LT and evaluate the contribution of growth on bone mineral density (BMD) changes.

METHODS

We studied six patients (two male), with a median age at transplantation of 8.8 (range 3.8-16.6) years. Indications for transplantation were biliary atresia and progressive familial intrahepatic cholestasis (three patients each). BMD was studied with dual-energy x-ray absorptiometry and biochemical markers of liver and bone function in patients before and at 3, 6, and 12 months after LT.

RESULTS

Median L2-L4 spinal BMD was 0.54 g/cm2 (range 0.29-0.87) before LT, and 0.58 g/cm2 (0.27-0.86) at 3 months, 0.66 g/cm2 (0.36-1.00) at 6 months, and 0.76 g/cm2 (0.44-1.02) at 12 months after LT (P=0.005). Median height was 133 (range 93-167) cm before LT, and 134 (93-167) at 3 months, 136 (97-167) at 6 months, and 139 (102-167) at 12 months after LT. There was direct correlation between height gain and total body BMD improvement (r=0.929, P=0.007).

CONCLUSION

BMD in children with chronic cholestatic liver disease improves remarkably by 12 months after LT. Catch-up growth in children can account for the different effect of LT on bone density between adult and pediatric populations in the first year after surgery.

Vertebral morphometry by X-ray absorptiometry before and after liver transplant: a cross-sectional study

OBJECTIVES

To evaluate bone density and fracture prevalence in patients with end-stage liver diseases (ESLD) awaiting liver transplant and in orthotopic liver-transplant (OLTx) recipients by using dual energy X-ray absorptiometry.

DESIGN

In a cross-sectional study 27 patients (16 males and 11 females, mean age 49.9 +/- 1.7 years) with ESLD, and 36 subjects (26 males and 10 females, mean age 50.5 +/- 1.6 years) who had undergone OLTx 1-70 months before, were recruited.

METHODS

All patients underwent biochemical assessment of mineral metabolism. Bone density measurement of the spine and femur and morphometric X-ray absorptiometry (MXA) of the vertebrae were also obtained.

RESULTS

Bone density was decreased in both groups as compared to the expected normal values. Spinal density did not differ between the two groups, while femoral bone mass was lower in OLTx than in ESLD patients (T-scores of: femoral neck -1.91 +/- 0.16 vs -1.12 +/- 0.22, P < 0.01; total femur -1.62 +/- 0.16 vs -0.94 +/- 0.23, P < 0.02). Bone alkaline phosphatase was the only independent predictor of femoral density (R2 = -0.21, P < 0.05). Symptomatic fractures were reported by 25% of OLTx and 15% of ESLD patients. MXA vertebral fractures were present in 28% of OLTx and 7.5% of ESLD (P < 0.05) patients. Most of these fractures had been asymptomatic. Total methylprednisolone intake was higher in patients with MXA vertebral fractures than in non-fractured patients (P < 0.05).

CONCLUSIONS

Fragility fractures, especially of the spine, occur more frequently after liver transplantation, with corticosteroid treatment being the most important risk factor. Morphometric X-ray absorptiometry represents a useful technique for identifying vertebral fractures even in liver transplanted patients.

Management of osteoporosis in primary biliary cirrhosis

Osteoporosis is not a significant problem in the majority of patients with primary biliary cirrhosis (PBC). However, substantial bone-related morbidity may occur in patients with advanced disease, in particular after liver transplantation. The cause of osteoporosis in PBC is multifactorial, and pathophysiological mechanisms specifically related to PBC have not been defined. In general, the principles of management followed in post-menopausal osteoporosis also apply in chronic liver disease. Dual energy X-ray absorptiometry is currently the method of choice for monitoring bone mineral density. Avoidance of conditions with potential negative effects on bone mass, and maintaining adequate serum vitamin D levels and calcium intake form the cornerstone in preventing osteoporosis. Bisphosphonates are the most logical choice when specific medical treatment of PBC-associated osteoporosis is indicated, as well as for preventing bone loss during glucocorticoid treatment and after liver transplantation. Recent studies suggest that active vitamin D analogues are effective alternatives in the post-transplant setting.

The localization of the functional glucocorticoid receptor alpha in human bone

Glucocorticoids have well-documented effects on the skeleton, although their mechanism of action is still poorly understood. The actions of glucocorticoids on bone cells are mediated, in part, directly via specific receptors. The presence of these receptors has been demonstrated in both rodent and human osteoblastic cells in vitro, but their presence in human bone in vivo has not been reported. In this study, we have used specific affinity purified polyclonal antibodies to the functional glucocorticoid receptor alpha (GRalpha) to investigate its expression in both developing and adult human bone using sections of neonatal rib, calvarial, and vertebral bones, tibial growth plates from adolescents, and iliac crest biopsies from adults who were to undergo liver transplantation. In the tibial growth plates, GRalpha was predominantly expressed in the hypertrophic chondrocytes within the cartilage. In the primary spongiosa, the receptor was highly expressed by osteoblasts at sites of bone modeling. Within the bone marrow, receptors were also detected in mononuclear cells and in endothelial cells of blood vessels. In the neonatal rib and vertebrae, GRalpha was widely distributed at sites of endochondral bone formation in resting, proliferating, mature, and hypertrophic chondrocytes. They were also highly expressed in osteoblasts at sites of bone modeling. At sites of intramembranous ossification in neonatal calvarial bone and rib periosteum, GRa was widely expressed in cells within the fibrous tissue and in osteoblasts at both the bone-forming surface and at modeling sites. In the iliac crests from adults, GRalpha was predominantly expressed in osteocytes. The receptors were not detected in osteoclasts. Our results show for the first time the presence of the functional GRalpha in human bone in situ and suggest that the actions of glucocorticoids on bone may be mediated, in part, directly via the GR at different stages of life. The absence of receptor expression in osteoclasts also suggests that the effects of glucocorticoids on bone resorption may be mediated indirectly.

Predicting bone loss following orthotopic liver transplantation

BACKGROUND

Hepatic osteodystrophy occurs in the majority of patients with advanced chronic liver disease with the abnormalities in bone metabolism accelerating following orthotopic liver transplantation (OLT).

AIMS

To examine changes in bone mineral density (BMD) following OLT and to investigate factors that lead to bone loss.

METHODS

Twelve patients had BMD (at both the lumbar spine (LS) and femoral neck (FN)) and biochemical markers measured preoperatively and for 24 months following OLT.

RESULTS

BMD was low in 75% of patients prior to OLT and decreased significantly from baseline at the LS at three months and the FN at six months. BMD began to increase thereafter at both sites, approaching baseline values at the LS by 12 months. Bone formation markers, osteocalcin and procollagen type I carboxy propeptide, decreased immediately post-OLT, with a concomitant increase seen in the resorption markers pyridinoline and deoxypyridinoline. This resulted in a negative uncoupling index early post-OLT, that rebounded to positive values after six months. There was a significant correlation between the change in the uncoupling index between six and three months which preceded the increase in BMD at 12 months. The decrease in BMD recorded early post-OLT correlated with vitamin D levels at three months.

CONCLUSIONS

Results suggest that increased resorption and inadequate formation are the major contributors to additional bone loss following OLT. Non-invasive biochemical markers precede later changes in BMD in this patient group following OLT and may have a role in investigating and planning intervention strategies to prevent bone loss in future studies.

Mechanism of bone loss after liver transplantation: A histomorphometric analysis

Organ transplantation is associated with increased bone loss and high fracture risk, but the pathophysiological mechanisms responsible have not been established. We have performed a histomorphometric analysis of bone remodeling before and 3 months after liver transplantation in 21 patients (14 male, 7 female) aged 38-68 years with chronic liver disease. Eight-micrometer undecalcified sections of trans-iliac biopsies were assessed using image analysis. Preoperatively, bone turnover was low with a tendency toward reduced wall width and erosion depth. The bone formation rate increased from 0.021 +/- 0.016 (mean +/- SD) to 0.067 +/- 0.055 microm2/microm/day after transplantation (p < 0.0002) and activation frequency from 0.24 +/- 0.21/year-1 to 0.81 +/- 0. 67/year-1 (p < 0.0001). No significant change was observed in wall width, but there was a trend toward an increase in indices of resorption cavity size. There was a small increase in osteoid seam width postoperatively (p< 0.02) and decrease in mineralization lag time (p < 0.001). No significant changes in indices of cancellous bone structure were observed in the postoperative biopsies. These results demonstrate a highly significant and quantitatively large increase in bone turnover in the first 3 months after liver transplantation. Although no significant disruption of cancellous bone structure was demonstrated during the time course of the study, the observed changes in bone remodeling predispose to trabecular penetration and may thus result in long-term adverse effects on bone strength.

Bone metabolism in orthotopic liver transplantation: a prospective study

Bone mineral density (BMD) and mineral metabolism were assessed in 54 patients with end-stage liver disease who were evaluated for orthotopic liver transplantation (OLT) and assessed 3, 6, and 12 months after surgery in 26 patients who underwent OLT. Serum and urinary electrolyte and mineral levels, serum liver function test results, and parathyroid hormone (PTH), osteocalcin (BGP), 25-hydroxyvitamin D, and urinary hydroxyproline levels were assessed. BMD of the lumbar spine was measured at baseline and 3, 6, and 12 months after OLT. At baseline, 40.7% of patients had BMD below the fracture threshold (0.800 g/cm2). Using multiple stepwise regression analysis, we found that BMD was significantly (P < .0001) affected by age, serum creatinine level, and PTH level but not by indices of cholestasis or liver function. In the patients who underwent OLT, a 1.4% reduction (P < .006) was observed in BMD 3 months after OLT. Thereafter, BMD returned to pretransplant values. A significant increase in serum BGP was observed after 6 (P < .02) and 12 (P < . 005) months. PTH levels increased progressively 3 (P < .02), 6 (P < . 001), and 12 (P < .0001) months after OLT. This increase did not seem to be caused by cyclosporine-induced nephropathy. It was concluded that osteopenia is a major complication in hepatic cirrhosis, regardless of its causes. The increase in serum BGP levels 6 and 12 months after OLT indicates metabolic activation of osteoblasts. The increase in PTH levels after OLT warrants further investigation.