Effects of alendronate on bone mineral density and bone metabolic markers in patients with liver transplantation

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

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

Increased Imminent Fracture Risk in Liver Transplant Recipients Despite Bisphosphonate Therapy

BACKGROUND

Bone loss is significant after orthotopic liver transplant (OLT) and is associated with increased fracture risk and decreased quality of life. In post-transplant fracture prevention, the cornerstone of therapeutic management is bisphosphonates.

METHODS

We conducted a retrospective study in a cohort of 155 OLT recipients who received a bisphosphonate prescription at hospital discharge between 2012 and 2016 to investigate post-OLT fragility fracture incidence and predictive risk factors.

RESULTS

Before OLT, 14 patients presented a T score < -2.5 SD, and 23 patients (14.8%) had a history of fracture. During follow-up, the cumulative incidence of fractures on bisphosphonates (99.4% risedronate/alendronate) was 9.7% at 12 months and 13.1% at 24 months. The median time to first fragility fracture was 10 months (IQR, 3-22 months) and thus within the first 2 years of follow-up. Predictive factors of fragility fractures in multivariate Cox regression analyses included age 60 years or older (hazard ratio [HR], 2.61; 95% CI, 1.14-6.01; P = .02), post-transplant diabetes mellitus (HR, 3.82; 95% CI, 1.55-9.44; P = .004), and cholestatic disease (HR, 5.93; 95% CI, 2.30-15.26; P = .0002). Additionally, the female sex was associated with a strong trend toward increased fracture risk in univariate analysis (HR, 2.27; 95% CI, 1.00-5.15; P = .05), as well as a post-transplant absolute decrease in bone mineral density at the femoral neck and total hip (P = .08).

CONCLUSIONS

This real-world study reports a high incidence of fractures post-OLT despite bisphosphonate therapy. Age 60 years or older, post-transplant diabetes mellitus, cholestatic disease, female sex, and femoral neck and/or total hip bone mineral density loss contribute to increased imminent fracture risk in liver transplant recipients.

Bone Disease and Liver Transplantation: A Review

Liver transplantation is currently the most effective and almost routine treatment for chronic and acute liver diseases. The survival of transplanted patients has increased exponentially, which has led to more knowledge of the long-term complications secondary to the underlying pathology or the various treatments that must be followed. Bone metabolic disease is a chronic complication of liver transplantation that inhibits quality of life. The factors that contribute to the development of bone disease are different according to the various etiologies of liver damage. All patients should be examined for osteoporosis risk factors because the incidence of new fractures in transplant patients is higher during the first year after transplantation, reflecting the greater bone loss during this time. This article outlines a proposal for a treatment algorithm; we propose that pharmacologic therapy in patients post liver transplant should first consider the diagnosis of osteoporosis by bone mineral density, the patient's personal and family history of spine and femoral neck fractures, and the use glucocorticoids (dose and time) until a tool is available that allows the best estimation of the fracture risk in this population of patients.

Bisphosphonate therapy after liver transplant improves bone mineral density and reduces fracture rates: an updated systematic review and meta-analysis

To investigate the efficacy of bisphosphonates and compare oral and IV formulations on bone mineral density (BMD) and fracture incidence in post-orthotopic liver transplant (OLT) patients. Electronic databases were searched, and six RCTs and three cohort studies were included out of 711 articles. Main outcomes included post-OLT BMD changes, fracture incidence, and treatment adverse reactions. Pairwise meta-analysis was conducted for binary and continuous outcomes, while pooled fracture incidence utilized single-arm meta-analysis. Post-OLT fracture incidence was reported in nine studies (n = 591). Total fracture incidence was 6.6% (CI: 3.4-12.4%) in bisphosphonate group and 19.1% (CI: 14.3-25.1%) in calcium and vitamin D group. Total fractures were significantly lower in patients on bisphosphonate, compared to calcium and vitamin D (n = 591; OR = 0.037; CI: 0.18-0.77; P = 0.008). Overall fractures were significantly lower in the oral group (n = 263; OR = 0.26; CI: 0.08-0.85; P = 0.02) but not in the IV group (n = 328; OR = 0.45; CI: 0.16-1.26; P = 0.129). Both oral and IV bisphosphonates are effective in reducing fracture incidence post-OLT compared to calcium and vitamin D. Oral formulations may also have an advantage over IV in reducing bone loss and fracture incidence post-OLT.

Management of Autoimmune Liver Diseases after Liver Transplantation

Autoimmune liver diseases are characterized by immune-mediated inflammation and eventual destruction of the hepatocytes and the biliary epithelial cells. They can progress to irreversible liver damage requiring liver transplantation. The post-liver transplant goals of treatment include improving the recipient’s survival, preventing liver graft-failure, and decreasing the recurrence of the disease. The keystone in post-liver transplant management for autoimmune liver diseases relies on identifying which would be the most appropriate immunosuppressive maintenance therapy. The combination of a steroid and a calcineurin inhibitor is the current immunosuppressive regimen of choice for autoimmune hepatitis. A gradual withdrawal of glucocorticoids is also recommended. On the other hand, ursodeoxycholic acid should be initiated soon after liver transplant to prevent recurrence and improve graft and patient survival in primary biliary cholangitis recipients. Unlike the previously mentioned autoimmune diseases, there are not immunosuppressive or disease-modifying agents available for patients with primary sclerosing cholangitis. However, colectomy and annual colonoscopy are key components during the post-liver transplant period.

Risk Factors and Management of Osteoporosis Post-Transplant

Bone and mineral disorders are common after organ transplantation. Osteoporosis post transplantation is associated with increased morbidity and mortality. Pathogenesis of bone disorders in this particular sub set of the population is complicated by multiple co-existing factors like preexisting bone disease, Vitamin D deficiency and parathyroid dysfunction. Risk factors include post-transplant immobilization, steroid usage, diabetes mellitus, low body mass index, older age, female sex, smoking, alcohol consumption and a sedentary lifestyle. Immunosuppressive medications post-transplant have a negative impact on outcomes, and further aggravate osteoporotic risk. Management is complex and challenging due to the sub-optimal sensitivity and specificity of non-invasive diagnostic tests, and the underutilization of bone biopsy. In this review, we summarize the prevalence, pathophysiology, diagnostic tests and management of osteoporosis in solid organ and hematopoietic stem cell transplant recipients.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Bone Diseases in Patients with Chronic Liver Disease

Osteoporosis is a frequently observed complication in patients with chronic liver disease, particularly liver cirrhosis and cholestatic liver diseases. In addition, osteoporosis is critical in patients receiving a liver transplant. Nevertheless, few studies have evaluated bone diseases in patients with more frequently observed chronic liver disease, such as chronic viral hepatitis, nonalcoholic fatty liver disease and alcoholic liver disease. Osteoporosis is a disease caused by an imbalance in the activities of osteoblasts and osteoclasts. Over the last few decades, many advances have improved our knowledge of the pathogenesis of osteoporosis. Importantly, activated immune cells affect the progression of osteoporosis, and chronic inflammation may exert an additional effect on the existing pathophysiology of osteoporosis. The microbiota of the intestinal tract may also affect the progression of bone loss in patients with chronic liver disease. Recently, studies regarding the effects of chronic inflammation on dysbiosis in bone diseases have been conducted. However, mechanisms underlying osteoporosis in patients with chronic liver disease are complex and precise mechanisms remain unknown. The following special considerations in patients with chronic liver disease are reviewed: bone diseases in patients who underwent a liver transplant, the association between chronic hepatitis B virus infection treatment and bone diseases, the association between sarcopenia and bone diseases in patients with chronic liver disease, and the association between chronic liver disease and avascular necrosis of the hip. Few guidelines are currently available for the management of low bone mineral density or bone diseases in patients with chronic liver disease. Due to increased life expectancy and therapeutic advances in chronic liver disease, the importance of managing osteoporosis and other bone diseases in patients with chronic liver disease is expected to increase. Consequently, specific guidelines need to be established in the near future.

EASL Clinical Practice Guidelines on nutrition in chronic liver disease

A frequent complication in liver cirrhosis is malnutrition, which is associated with the progression of liver failure, and with a higher rate of complications including infections, hepatic encephalopathy and ascites. In recent years, the rising prevalence of obesity has led to an increase in the number of cirrhosis cases related to non-alcoholic steatohepatitis. Malnutrition, obesity and sarcopenic obesity may worsen the prognosis of patients with liver cirrhosis and lower their survival. Nutritional monitoring and intervention is therefore crucial in chronic liver disease. These Clinical Practice Guidelines review the present knowledge in the field of nutrition in chronic liver disease and promote further research on this topic. Screening, assessment and principles of nutritional management are examined, with recommendations provided in specific settings such as hepatic encephalopathy, cirrhotic patients with bone disease, patients undergoing liver surgery or transplantation and critically ill cirrhotic patients.

Diagnosis and Management of Cirrhosis-Related Osteoporosis

Management of cirrhosis complications has greatly improved, increasing survival and quality of life of the patients. Despite that, some of these complications are still overlooked and scarcely treated, particularly those that are not related to the liver. This is the case of osteoporosis, the only cirrhosis complication that is not solved after liver transplantation, because bone loss often increases after immunosuppressant therapy. In this review, the definitions of bone conditions in cirrhotic patients are analyzed, focusing on the more common ones and on those that have the largest impact on this population. Risk factors, physiopathology, diagnosis, screening strategies, and treatment of osteoporosis in cirrhotic patients are discussed, presenting the more striking data on this issue. Therapies used for particular conditions, such as primary biliary cirrhosis and liver transplantation, are also presented.

Osteoporosis in the adult solid organ transplant population: underlying mechanisms and available treatment options

The prevention and treatment of osteoporosis is an increasingly important topic in the solid organ transplant (SOT) population. Compared to the general population, these patients are at an elevated risk of developing osteoporosis due to progressive disease, lifelong immunosuppressant therapy, and malnutrition. As patients live longer after transplant, chronic disease management is increasingly more important. Supplementation with calcium and vitamin D is often necessary in the SOT population due to a high incidence of vitamin D deficiency. Bisphosphonate therapy is most commonly used for prevention and treatment of osteoporosis, but therapy can be limited by renal dysfunction which is common in transplant recipients. Alternative agents such as teriparatide and calcitonin have not been shown to provide a significant impact on the rate of fractures in this population. Additionally, denosumab may be a promising treatment option due to its novel mechanism of action, and is currently being studied in renal transplant patients. Timely initiation of supplementation and treatment, and minimizing glucocorticoid exposure prior to and after transplantation will aid in the prevention and proper management of osteoporosis in these patients.

Randomized trial comparing monthly ibandronate and weekly alendronate for osteoporosis in patients with primary biliary cirrhosis

Osteoporosis resulting in bone fractures is a complication in patients with primary biliary cirrhosis (PBC). Once-weekly alendronate improves bone mass and is well tolerated in these patients, but there is a concern because of poor compliance. Therefore, the efficacy, adherence, and safety of monthly ibandronate (150 mg) with weekly alendronate (70 mg) were compared in a randomized, 2-year study in 42 postmenopausal women with PBC and osteoporosis. Bone mineral density (BMD) of the lumbar spine and proximal femur (by DXA), liver function, and bone markers were measured at entry and every 6 months over 2 years. Adherence to therapy was assessed by the Morisky-Green score. At enrollment, the two groups were similar with respect to age, BMD, severity of cholestasis, previous fractures, and bone markers. Thirty-three patients, 14 in the ibandronate group and 19 in the alendronate group, completed the trial. At 2 years both treatments resulted in a significant increase in BMD at the lumbar spine (from 0.875 ± 0.025 to 0.913 ± 0.026 g/cm(2), P < 0.001 with alendronate, and from 0.898 ± 0.024 to 0.949 ± 0.027 g/cm(2), P < 0.001 with ibandronate). The mean percentage change was 4.5% and 5.7%, respectively (P = not significant). BMD increased at the total hip by 2.0% and 1.2%, respectively. Changes in bone markers were similar in both groups and one patient with alendronate developed a new vertebral fracture. Adherence to therapy was higher with ibandronate (P = 0.009). Neither treatment impaired liver function or cholestasis.

CONCLUSION

Both regimens, weekly alendronate and monthly ibandronate, improve bone mass and are comparable in safety for osteoporosis therapy in patients with PBC, although adherence is higher with the monthly regimen. Further larger studies are needed to assess fracture prevention.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effect of alendronate on bone-specific alkaline phosphatase on periodontal bone loss in rats

OBJECTIVE

The study aims to evaluate the effect of alendronate (ALD) on bone-specific alkaline phosphatase (BALP) serum levels on periodontal bone loss in Wistar rats.

DESIGN

Periodontitis was induced by ligature around the upper second molar in 36 male Wistar rats (± 200 g). Groups of six animals received 0.9% saline (SAL) or ALD (0.01; 0.05; 0.25 mgkg(-1), s.c.), over 11 days; then they were sacrificed and their maxillae were removed to be defleshed and stained for macroscopic or histopathological analysis. Blood samples were collected for BALP, transaminases and total alkaline phosphatase (TALP) serum dosage, and haematologic study. Rats were weighed daily.

RESULTS

Periodontitis induction caused reduction of BALP, intense alveolar bone loss (ABL), cementum and periodontal ligament destructions and intense leucocyte infiltration seen microscopically. Systemically, periodontitis induced leucocytosis, weight loss and TALP reduction. ALD (0.25 mgkg(-1)) prevented BALP reduction (19.17 ± 1.36 Ul(-1)) when compared to SAL (13.6 ± 1.5), as well as prevented ABL, by 57.2%, when compared to SAL (4.80+0.18 mm(2)), which was corroborated by histological findings (ALD 0.25 mgkg(-1)=1.5 (1-2) and SAL=3 (2-3)) (p<0.05). ALD did not alter transaminases but reduced TALP levels (p<0.05). ALD 0.25 mgkg(-1) reduced 6th-h neutrophilia (2.50 ± 0.22cell × 10(3)mm(-3)) and 7th- (12.29 ± 0.66) and 11th-day lymphomonocytosis (15.74 ± 0.52) when compared to SAL (5.20 ± 0.28; 18.24 ± 1.05; and 23.21 ± 1.48, respectively). ALD did not alter the weight loss.

CONCLUSION

ALD prevented BALP reduction and ABL and reduced inflammatory infiltrate, without causing systemic alterations.

Nutritional interventions for liver-transplanted patients

BACKGROUND

Malnutrition is a common problem for patients waiting for orthotopic liver transplantation and a risk factor for post-transplant morbidity. The decision to initiate enteral or parenteral nutrition, to which patients and at which time, is still debated. The effects of nutritional supplements given before or after liver transplantation, or both, still remains unclear.

OBJECTIVES

The aim of this review was to assess the beneficial and harmful effects of enteral and parenteral nutrition as well as oral nutritional supplements administered to patients before and after liver transplantation.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register (March 2012), the Cochrane Central Register of Controlled Trials (Issue 2 of 12, 2012) in The Cochrane Library, MEDLINE (January 1946 to March 2012), EMBASE (January 1974 to March 2012), Science Citation Index Expanded (January 1900 to March 2012), Social Science Citation Index (January 1961 to October 2010), and reference lists of articles. Manufacturers and experts in the field have also been contacted and relevant journals and conference proceedings were handsearched (from 1997 to October 2010).

SELECTION CRITERIA

Randomised clinical trials of parallel or cross-over design evaluating the beneficial or harmful effects of enteral or parenteral nutrition or oral nutritional supplements for patients before and after liver transplantation were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias of the trials and extracted data. Dichotomous data were reported as odds ratios (OR) and continuous data as mean differences (MD) along with their corresponding 95% confidence intervals (CI). Meta-analysis was not possible due to clinical heterogeneity of included interventions.

MAIN RESULTS

Thirteen trials met the inclusion criteria. Four publications did not report outcomes pre-defined in the review protocol, or other clinically relevant outcomes and additional data could not be obtained. Nine trials could provide data for the review. Most of the 13 included trials were small and at high risk of bias. Meta-analyses were not possible due to clinical heterogeneity of the interventions.No interventions that were likely to be beneficial were identified.For interventions of unknown effectiveness,postoperative enteral nutrition compared with postoperative parenteral nutrition seemed to have no beneficial or harmful effects on clinical outcomes. Parenteral nutrition containing protein, fat, carbohydrates, and branched-chain amino acids with or without alanyl-glutamine seemed to have no beneficial effect on the outcomes of one and three years survival when compared with a solution of 5% dextrose and normal saline. Enteral immunonutrition with Supportan® seemed to have no effect on occurrence of immunological rejection when compared with enteral nutrition with Fresubin®.There is weak evidence that, compared with standard dietary advice, adding a nutritional supplement to usual diet for patients during the waiting time for liver transplantation had an effect on clinical outcomes after liver transplantation. The combination of enteral nutrition plus parenteral nutrition plus glutamine-dipeptide seemed to be beneficial in reducing length of hospital stay after liver transplantation compared with standard parenteral nutrition (mean difference (MD) -12.20 days; 95% CI -20.20 to -4.00). There is weak evidence that the use of parenteral nutrition plus branched-chain amino acids had an effect on clinical outcomes compared with standard parenteral nutrition, but each was beneficial in reducing length of stay in intensive care unit compared to a standard glucose solution (MD -2.40; 95% CI -4.29 to -0.51 and MD -2.20 days; 95% CI -3.79 to -0.61). There is weak evidence that adding omega-3 fish oil to parenteral nutrition reduced the length of hospital stay after liver transplantation (mean difference -7.1 days; 95% CI -13.02 to -1.18) and the length of stay in intensive care unit after liver transplantation (MD -1.9 days; 95% CI -1.9 to -0.22).For interventions unlikely to be beneficial, there is a significant increased risk in acute rejections in malnourished patients with a history of encephalopathy and treated with the nutritional supplement Ensure® compared with usual diet only (MD 0.70 events per patient; 95% CI 0.08 to 1.32).

AUTHORS' CONCLUSIONS

We were unable to identify nutritional interventions for liver transplanted patients that seemed to offer convincing benefits. Further randomised clinical trials with low risk of bias and powerful sample sizes are needed.

Medical management of the liver transplant recipient

Long-term survival of liver transplant recipients has become the rule rather than the exception. As a result, the medical complications of long-term survival, including atherosclerotic cardiovascular disease, metabolic bone disease, and de novo malignancy, have accounted for an increasing proportion of late morbidity and mortality. Risk factors for these complications begin before transplant and are potentially modifiable but are exacerbated by the requirement for immunosuppressive medications after transplantation. Surveillance and early intervention programs administered by transplant hepatologists and other medical subspecialists may improve long-term outcomes in liver transplant recipients by ameliorating risk factors for atherosclerosis, bone fractures, and cancer.

Fracture incidence after liver transplantation: results of a 10-year audit

BACKGROUND

High rates of fracture following liver transplantation were reported in earlier years, but the impact of subsequent changes in immune suppression and the introduction of bone-protective therapy on fracture rate have not been reported.

AIM

The aim of this study was to document clinical fracture incidence during the period 1998-2008 in a single transplant centre, following the introduction of a bone management protocol.

DESIGN

It was designed as a retrospective cohort.

METHODS

Records were retrieved from 531 of 592 eligible patients in an audit of all patients undergoing a first liver transplant during the 10-year period. All fractures were verified radiologically.

RESULTS

The mean follow-up period was 61.4 months. Prior to transplantation 5.6% of patients had a history of fracture. Incident clinical fractures following transplantation were recorded in just 15 (3.5%) patients. The most common fracture site was the spine and the median time from transplant to fracture was 26 months (range 2-83 months).

CONCLUSION

There was a low fracture rate in patients undergoing liver transplantation in this centre over the past 10 years. This rate is lower than that in previous reports, which is likely to reflect the use of lower doses of prednisolone for immune suppression and the administration of bone-protective therapy to high-risk patients.

Management of osteoporosis in liver disease

Osteoporosis resulting in a high risk for fracture is a common complication in patients with liver disease, particularly in those with chronic cholestasis and with end-stage cirrhosis. The pathogenesis of bone loss in liver patients is poorly understood but it mainly results from low bone formation as a consequence of cholestasis or the harmful effects of alcohol or iron on osteoblasts. Increased bone resorption has also been described in cholestatic women with advanced disease. The management of bone disease in liver patients is addressed to reduce or avoid the risk factors for osteoporosis and fracture. Bisphosphonates associated with supplements of calcium and vitamin D are safe and effective for increasing bone mass in patients with chronic cholestasis and after liver transplantation, though no clear achievements in descreasing the incidence of fractures have been described, probably because of the low number of patients included in the therapeutic trials. Randomized studies assessing bisphosphonates in larger series of patients, the development of new drugs for osteoporosis and the improvement in the management of liver transplant recipients may change the future.

Assessing bone status in patients awaiting liver transplantation

Osteoporosis is common in liver transplant recipients as a result of both iatrogenic factors and preexisting hepatic osteodystrophy.

OBJECTIVES

To assess the prevalences of osteoporosis and fractures and to identify risk factors for these two abnormalities in patients awaiting liver transplantation for end-stage liver disease.

METHODS

Between January 2006 and December 2007, patients on a liver transplant waiting list underwent a routine evaluation comprising the identification of risk factors for osteoporosis, radiographs of the spine, bone mineral density measurements (BMD), and laboratory tests (phosphate and calcium levels, hormone assays, liver function tests, and bone turnover markers).

RESULTS

We studied 99 patients (70 males and 20 females; mean age, 55 ± 8 years) including 75% with alcohol-induced cirrhosis with or without hepatocarcinoma. Among them, 36% had radiographic vertebral fractures, 38% had osteoporosis, 35% had osteopenia, and 88% had vitamin D insufficiency or deficiency (25(OH)vitamin D3<20 ng/mL). Lower BMD values were associated with vertebral fractures; the odds ratios and 95% confidence intervals for each BMD decrease of 1 SD were as follows: spine, 1.45 (95%CI, 1.1-1.9); total hip, 2.1 (95%CI, 1.3-3.2); and femoral neck, 2 (95%CI, 1.3-3.1) (P<0.05). Levels of bone resorption markers correlated negatively with BMD at the spine and hip. The Model for End-Stage Liver Disease score correlated negatively with hip BMD.

CONCLUSION

Our findings suggest high prevalences of low BMD values and vertebral fractures among patients awaiting liver transplantation. Bone status should be evaluated routinely in candidates to liver transplantation.

Effect of early risedronate treatment on bone mineral density and bone turnover markers after liver transplantation: a prospective single-center study

The aim of this study was to investigate the effect of risedronate (RIS) on bone loss and bone turnover markers after liver transplantation (LT). Patients with osteopenia or osteoporosis within the first month after LT were randomized to receive RIS 35 mg/week plus calcium 1000 mg/day and vitamin D(3) 800 IU/day (n = 45) or calcium and vitamin D(3) at same dosages (n = 44). Primary endpoint was change in bone mineral density (BMD) 6 and 12 months after LT. Secondary endpoints included changes in serum β-CrossLaps (β-CTX) and procollagen type 1 amino-terminal peptide (P1NP) and fracture rate. Spine X-rays were obtained at baseline and after 12 months. There was no significant difference in BMD changes between both treatment groups at any sites; either at 6 or 12 months. Spine BMD increased in both groups at 12 months vs. baseline (P = 0.001). RIS patients had a significant increase in intertrochanteric BMD at 12 months (P < 0.05 vs. baseline). Serum β-CTX decreased in both groups (P < 0.01), with significant differences between groups at 3 months. No significant difference in vertebral fracture incidence was found. After 12 months, BMD improved at lumbar spine and did not change at hip in both groups. Significant differences between both groups were not found. Other factors (calcium and vitamin D replacement, early prednisone withdrawal) seem to have also positive effects in BMD.

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

SUMMARY

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Liver and bone

Osteoporosis is a frequent complication in patients with chronic liver disease, especially in end-stages and in cases with chronic cholestasis, hemochromatosis and alcohol abuse. The problem is more critical in transplant patients when bone loss is accelerated during the period immediately after transplantation, leading to a greater incidence of fractures. Advanced age, low body mass index and severity of the liver disease are the main risk factors for bone disease in patients with cholestasis. Mechanisms underlying osteoporosis in chronic liver disease are complex and poorly understood, but osteoporosis mainly results from low bone formation, related to the effects of retained substances of cholestasis, such as bilirubin and bile acids, or to the effects of alcohol on osteoblastic cells. Increased bone resorption has also been described in cholestatic women with advanced disease. Although there is no specific treatment, bisphosphonates associated with supplements of calcium and vitamin D are effective for increasing bone mass in patients with chronic cholestasis and after liver transplantation. The outcome in reducing the incidence of fractures has not been adequately demonstrated essentially because of the low number of patients included in the therapeutic trials. Randomized studies assessing bisphosphonates in larger series of patients, the development of new drugs for osteoporosis and the improvement in the management of liver transplant recipients may change the future.

Effect of bisphosphonates on bone mineral density in liver transplant patients: a meta-analysis and systematic review of randomized controlled trials

SUMMARY

Bone mineral density (BMD) loss after liver transplantation (LT) results in considerable morbidity with the increased risk of fractures. Data on the efficacy of bisphosphonate use in post LT patients is scarce. This meta-analysis aims to summarize the results from published randomized controlled trials (RCTs) on the topic of interest. Electronic databases were searched to identify relevant publications. A total of 157 articles were identified and reviewed. Individual authors were contacted from relevant RCTs to obtain individual patient data where necessary to uniformly quantify BMD values post LT pre- and post LT. A total of six RCTs were used for final data extraction. (i) Lumbar Spine: In 364 patients (six studies, 182 in intervention and control groups each), bisphosphonate therapy improved BMD by 0.03 g/cm(2) (95% C.I. 0.01-0.05 g/cm(2); P = 0.02) at 12 months post LT. (ii) Femoral neck: In 268 patients (four studies, 130 bisphosphonate, 138 control), bisphosphonate use did not result in a statistically significant change in BMD at the end of 1 year. None of the studies noted serious adverse effects related to bisphosphonate administration. Data on incident fractures could not be pooled because of heterogeneity. Bisphosphonate therapy during the first year in LT recipients appears to reduce accelerated bone loss and improve bone mineral density at the lumbar spine.

Pamidronate in the prevention of bone loss after liver transplantation: a randomized controlled trial

Rapid bone loss and high rates of fractures occur following liver transplantation. To analyze the effect of intravenous pamidronate on bone loss after liver transplantation. A randomized, double-blind, placebo-controlled study was performed. Seventy-nine patients were randomized to two groups of treatment: the pamidronate group (n = 38) was treated with 90 mg/IV of pamidronate within the first 2 weeks and at 3 months after transplantation; the placebo group (n = 41) received glucose infusions at the same time points. All patients received calcium and vitamin D. Bone mineral density (BMD) at the lumbar spine (L(2)-L(4)) and proximal femur using dual energy X-ray absorptiometry and also spinal X-rays were performed before, and at 6 and 12 months after liver transplantation. Biochemical and hormonal determinations were performed previous to transplantation, at 24 h before and after treatment, as well as at 6 and 12 months after liver transplantation. At 12 months after transplantation, there were significant differences in lumbar BMD changes (6 months: pamidronate 1.6% vs. placebo 0.8%, P = NS; 12 months: pamidronate 2.9% vs. placebo 1%, P < 0.05). Femoral neck BMD decreased in the pamidronate- and placebo groups during the first 6 months (6 months: pamidronate -3.1% vs. placebo -2.9%, P = NS; 12 months: pamidronate -3.2% vs. placebo -3.1%, P = NS). BMD at the trochanter remained stable in the pamidronate group, whilst a reduction was observed in the placebo group at 6 months (6 months: pamidronate -0.7% vs. placebo -3.7%, P < 0.05; 12 months: pamidronate -0.5% vs. placebo -1.2%, P = NS). Moreover, no significant differences in the incidence of fractures, serum parathyroid hormone and serum 25-hydroxyvitamin D values between both groups were found. Pamidronate did not increase the risk of serious adverse events. The results of this study show that 90 mg of intravenous pamidronate within the first 2 weeks and at 3 months following liver transplantation preserve lumbar bone mass during the first year, without significant adverse events. However, pamidronate does not reduce bone loss at the femoral neck and furthermore it does not reduce skeletal fractures.

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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