Long-term effects of liver transplantation on bone mineral density in children with end-stage liver disease: a 2-year prospective study

Changes in thoracic radio density after living donor liver transplantation

BACKGROUND

The outcomes after liver transplantation have greatly improved, which has resulted in greater focus on improving non-hepatic outcomes of liver transplantation. The present study aimed to evaluate thoracic spine radio density in children and adolescents after liver transplantation.

METHODS

A total of 116 patients who underwent living donor liver transplantation were retrospectively analyzed. The radio density at the eleventh thoracic vertebra was measured using computed tomography scan performed preoperatively then annually for 5 years postoperatively and subsequently every 2 or 3 years.

RESULTS

The mean thoracic radio density of male recipients of male grafts had the lowest values during the study. The radio density of patients receiving a graft from a female donor was higher than in recipients with grafts from males. Total mean radio density decreased for first 5 years postoperatively and then increased. Changes in radio density were equally distributed in both steroid withdrawal and no steroid withdrawal groups for 5 years, after which patients with steroid withdrawal had a greater increase. Changes in radio density were equally distributed in both the steroid withdrawal and no steroid withdrawal groups up to age 20, after which patients in the steroid withdrawal group had a greater increase.

CONCLUSIONS

Gender differences may affect the outcome of radio density changes after transplantation. Given the moderate association between thoracic radio density and bone mineral density in skeletally mature adults and further studies are needed to validate this relationship between thoracic radio density and bone mineral density changes in pediatric liver transplantation.

Prevalence and Associated Factors of Vertebral Fractures in Children with Chronic Liver Disease with and without Liver Transplantation

Purpose

To evaluate the prevalence of vertebral fracture (VF) in children with chronic liver disease (CLD) with and without liver transplantation (LT) and to determine the associated factors.

Methods

A cross-sectional study was conducted. Patients aged 3-21 years with CLD both before and after LT were enrolled in the study. Lateral thoracolumbar spine radiographs were obtained and assessed for VF using Mäkitie's method. Clinical and biochemical data were collected.

Results

We enrolled 147 patients (80 females; median age 8.8 years [interquartile range 6.0-11.8]; 110 [74.8%] in the LT group and 37 [25.2%] in the non-LT group). VF was identified in 21 patients (14.3%): 17/110 (15.5%) in the LT group and 4/37 (10.8%) in the non-LT group (p=0.54). Back pain was noted in only three patients with VF. In the univariate analysis, a height z-score below -2.0 (p=0.010), pre-LT hepatopulmonary syndrome (p=0.014), elevated serum direct and total bilirubin levels (p=0.037 and p=0.049, respectively), and vitamin D deficiency at 1-year post-LT (p=0.048) were associated with VF in the LT group. In multivariate analysis, height z-score below -2.0 was the only significant associated factor (odds ratio, 5.94; 95% confidence interval, 1.49-23.76; p=0.012) for VF. All VFs in the non-LT group were reported in males.

Conclusion

In children with CLD, VF is common before and after LT. Most patients with VF are asymptomatic. Screening for VF should be considered in patients with a height z-score below -2.0 after LT.

Bone demineralization in a cohort of Egyptian pediatric liver transplant recipients: Single center pilot study

Liver transplantation (LT) is the definitive treatment of end-stage liver disease. The long-term survival following LT spurred more interest in improving the quality of life of patients. This was a cohort study that included 23 pediatric liver transplant recipients who underwent LT due to hereditary or metabolic liver diseases. Bone health assessment was performed at their last follow up clinically (anthropometric measures), biochemically and radiologically (Dual Energy X-ray Absorptiometry [DEXA] scans). Poor bone health was defined as z-score <-1. Mean age at LT was 5.77 years (standard deviation [SD] 3.64) and 43% were males. Biliary atresia was the most common cause of end stage liver disease (35%). Mean age at follow up was 14 years (SD 5.48) and mean follow up was 8 years (SD 4.12 years). Eleven patients (48%) had poor bone health (osteopenia 22% and osteoporosis 26%). On univariate analysis, being on steroids at last follow up (odds ratio [OR] 13.2, 95% confidence interval [CI] 1.23-140.67, P = .03), weight at last follow up (OR 0.45, 95% CI 0.20-0.99, P = .04), platelets at last follow up (OR 0.98, 95% CI 0.96-s0.99, P = .02), hemoglobin at last follow up (OR 0.33, 95% CI 0.12-0.89, P = .03) were significantly associated with poor bone health. None of the variables were significant on multivariate analysis. At most recent follow up, 48% of patients demonstrated poor bone health by DEXA scans. More studies are required to evaluate predictors of poor bone health after LT in children.

Serum Insulin-Like Growth Factor 1 Levels, Facture Risk Assessment Tool Scores and Bone Disorders in Patients with Primary Biliary Cholangitis

Insulin-like growth factor 1 (IGF-1) plays an important role in bone growth and maintenance, and its decreased levels are associated with bone disorders. This study aimed to evaluate the association of serum IGF-1 levels with osteoporosis, prevalent fractures and fracture risk based on the Fracture Risk Assessment Tool (FRAX) in patients with primary biliary cholangitis (PBC). This study included 127 consecutive patients with PBC. Based on the baseline serum IGF-1 levels, the participants were classified into the low (L)-, intermediate (I)- and high (H)-IGF-1 groups. According to the FRAX score, high fracture risk was defined as a 10-year major osteoporotic fracture probability (FRAX-MOF) ≥ 20% or a 10-year hip fracture probability (FRAX-HF) ≥ 3%. The serum IGF-1 levels were positively correlated with bone mineral density, and were negatively correlated with the FRAX-MOF/FRAX-HF. The L-IGF-1 group had the highest prevalence of osteoporosis (58.1%), prevalent fracture (48.4%) and high fracture risk (71.0%). Meanwhile, the H-IGF-1 group had the lowest prevalence of osteoporosis (9.7%), prevalent fracture (12.9%) and high fracture risk (9.7%). The prevalence of these events increased stepwise with decreasing serum IGF-1 levels. The cutoff values of IGF-1 for predicting osteoporosis, prevalent fracture and high fracture risk were 61.5 ng/mL (sensitivity/specificity, 0.545/0.894), 69.5 ng/mL (0.633/0.784) and 61.5 ng/mL (0.512/0.929), respectively. Serum IGF-1 levels were associated with bone disorders and the FRAX-derived fracture risk, and may be a useful indicator for initiating therapeutic intervention to prevent the incidence of fracture in patients with PBC.

Secondary Malnutrition and Nutritional Intervention in Cholestatic Liver Diseases in Infants

We aimed to conduct an updated review on the pathophysiology, diagnosis, and nutritional intervention of CCLD and secondary malnutrition in infants. Protein-energy malnutrition, impaired linear growth, fat-soluble vitamin deficiencies, and hepatic osteodystrophy can occur in up to 80% of cases. The proposed pathophysiological mechanisms include insufficient energy intake, lipid- and fat-soluble vitamin malabsorption, increased energy expenditure, altered intermediate metabolism, hormonal dysregulation, and systemic inflammation. The current approach to diagnosis is the identification of the deviation of growth parameters, body composition, and serum concentration of micronutrients, which determines the type and magnitude of malnutrition. Currently, liver transplantation is the best therapeutic alternative for the reversal of nutritional impairment. Early and effective portoenteroanatomosis can extend survival in patients with biliary atresia. Medical and dietary interventions in some storage and metabolic diseases can improve liver damage and thus the nutritional status. A proportion of patients with biliary atresia have fat-soluble vitamin deficiencies despite receiving these vitamins in a water-soluble form. With aggressive enteral nutrition, it may be possible to increase fat stores and preserve muscle mass and growth. The nutritional issues identified in the pre- and post-transplantation stages include muscle mass loss, bone demineralization, growth retardation, and obesity, which seems to correspond to the natural history of CCLD. Due to the implications for the growth and development of infants with CCLD with this complex malnutrition syndrome, innovative projects are required, such as the generation of prediction and risk models, biomarkers of growth and body composition, and effective strategies for nutritional prevention and intervention.

Nutrition Support of Children With Chronic Liver Diseases: A Joint Position Paper of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

Chronic liver disease places patients at increased risk of malnutrition that can be challenging to identify clinically and treat. Nutrition support is a key aspect of the management of these patients as it has an impact on their quality of life, morbidity, and mortality. There are significant gaps in the literature regarding the optimal nutrition support for patients with different types of liver diseases and the impact of these interventions on long-term outcomes. This Position Paper summarizes the available literature on the nutritional aspects of the care of patients with chronic liver diseases. Specifically, the challenges associated with the nutritional assessment of these subjects are discussed, and recently investigated approaches to determining the patients' nutritional status are reviewed. Furthermore, the pathophysiology of the malnutrition seen in the context of chronic liver disease is summarized and monitoring, as well as treatment, recommendations are provided. Lastly, suggestions for future research studies are described.

Vitamin D non-sufficiency is prevalent in children with chronic liver disease in a tropical country

BACKGROUND

To determine vitamin D status in children with chronic liver disease (CLD) in a tropical country.

METHODS

Cross-sectional study in Malaysian children with CLD. Factors affecting serum vitamin D level (definition: deficient < 30 nmol/L; insufficient 30-50 nmol/L; sufficient ≥ 50 nmol/L) was analyzed.

RESULTS

Of the 59 children studied (males 32, 54%; median age 6.8 ± 5.3 years), the three most common causes were biliary atresia (n = 25), autoimmune hepatitis (n = 16) and sclerosing cholangitis (n = 6). The overall mean daily vitamin D intake was 715 ± 562 units/day. Thirteen (22%) patients had at least one clinical signs of rickets. Seventeen (29%) had serum bilirubin level ≥ 34 μmol/L. Eight (14%) children were deficient in vitamin D, eight (14%) were vitamin D-insufficient and 43 (73%) were sufficient. As compared with children with serum bilirubin <34 μmol/L, those with serum bilirubin ≥34 μmol/L were more likely to have rickets (24% vs. 65%; P < 0.002) and a lower serum vitamin D level (86.0 ± 54.9 nmol/L vs. 65.4 ± 48.2 nmol/L; P = 0.05) despite being given a significantly higher vitamin D dose (608 ± 571 vs. 970 ± 543 units/day; P = 0.008). The proportion of children with either deficient or insufficient vitamin D status was significantly higher in children with bilirubin level ≥34 μmol/L than in children <34 μmol/L (47% vs. 19%; P = 0.028).

CONCLUSION

Vitamin D deficiency and insufficiency is common in children with CLD in a tropical country. Regular monitoring of vitamin D status and screening for metabolic bone disease in all children with CLD is recommended. Higher dose of oral supplement or parenteral route should be considered, especially in those with bilirubin ≥34 μmol/L.

Growth, body composition, and bone density following pediatric liver transplantation

Patients transplanted for cholestatic liver disease are often significantly fat-soluble vitamin deficient and malnourished pretransplant, with significant corticosteroid exposure post-transplant, with increasing evidence of obesity and metabolic syndrome post-LT. Our study aimed to assess growth, body composition, and BMD in patients post-pediatric LT. Body composition and bone densitometry scans were performed on 21 patients. Pre- and post-transplant anthropometric data were analyzed. Bone health was assessed using serum ALP, calcium, phosphate, and procollagen-1-N-peptide levels. Median ages at transplant and at this assessment were 2.7 and 10.6 years, respectively. Physiological markers of bone health, median z-scores for total body, and lumbar spine aBMD were normal. Bone area was normal for height and BMAD at L3 was normal for age, indicating, respectively, normal cortical and trabecular bone accrual. Median z-scores for weight, height, and BMI were 0.6, -0.9, 1.8 and 0.6, 0.1, 0.8 pre- and post-transplant, respectively. Total body fat percentages measured on 21 body composition scans revealed 2 underweight, 7 normal, 6 overweight, and 6 obese. Bone mass is preserved following pediatric LT with good catch-up height. About 52% of patients were either overweight/obese post-transplant, potentially placing them at an increased risk of metabolic syndrome and its sequelae in later life. BMI alone is a poor indicator of nutritional status post-transplant.

Low bone density and fractures before and after pediatric lung transplantation

INTRODUCTION

Children undergoing lung transplant are at risk for low bone mineral density (BMD) and fractures. The effect of lung transplantation on bone health in pediatric patients is unknown.

MATERIALS AND METHODS

We performed a retrospective chart review of all patients ages 2-21 years who underwent lung transplantation at our hospital from January 2000 to January 2015.

RESULTS

51 patients were studied. At the time of transplant evaluation, BMD Z-score was -2.2 ± 1.4, and 59% of patients had low BMD. BMD Z-score declined in the first year after treatment and returned to near-baseline by the third post-transplant year. Fractures occurred in 9 patients (18%) before and 15 patients (29%) after transplant. Bisphosphonate use was associated with improvement in BMD Z-score and lower mortality risk.

CONCLUSIONS

Pediatric patients had a high prevalence of low BMD at the time of lung transplant evaluation. BMD Z-scores declined in the year after transplant and returned to the pre-transplant level by the third post-transplant year while remaining below normal levels. Fractures were common at sites associated with significant morbidity. These findings support efforts to optimize bone health before and after pediatric lung transplantation, and future studies are needed to evaluate the role of bisphosphonates in these patients.

Bone Mineral Density of Very Long-term Survivors After Childhood Liver Transplantation

OBJECTIVES

Liver transplant patients are at risk of osteopenia and fractures but limited information is available in long-term survivors after childhood transplantation. This study aimed to assess bone mineral density (BMD) of very long-term, >5 years, survivors after liver transplantation in childhood.

METHODS

Patients aged <18 years at transplant, having survived >5 years after transplant were potentially eligible but only those with ongoing review in our state were included. Dual-energy x-ray absorptiometry (DXA) was used to measure BMD. Patients aged <20 years had lumbar spine (LS) and total body (TB) measurements whereas those aged 20 years or more had LS and femoral neck but not TB. BMD z-scores for LS and TB, if available, were used in this study. BMD z-score ≤-2.0 was considered reduced. Pre-pubertal children had radiologic bone age assessment.

RESULTS

Forty-two patients, 17 boys, participated of whom 64% had biliary atresia. Median age at transplant was 2.22 (range 0.38-14.25) years; time since transplant 10.10 (5.01-25.98) years; and age at DXA 14.64 (6.59-38.07) years. Mean BMD z-scores were LS -0.15 ± 1.07, and TB -0.76 ± 1.14, with no sex difference noted. Four (9.5%) patients had reduced LS BMD, and although ongoing steroid use was more frequent in these patients, other comorbidities were likely important. Age at transplant, time since transplant, height, weight, and body mass index at DXA did not predict LS BMD. Pathologic fractures occurred in 2 of 42 (5%) patients; all within 18 months of transplant.

CONCLUSIONS

Very long-term survivors after childhood liver transplant have LS BMD within the normal range.

Reduced Serum IGF-1 Associated With Hepatic Osteodystrophy Is a Main Determinant of Low Cortical but Not Trabecular Bone Mass

Hepatic osteodystrophy is multifactorial in its pathogenesis. Numerous studies have shown that impairments of the hepatic growth hormone/insulin-like growth factor-1 axis (GH/IGF-1) are common in patients with non-alcoholic fatty liver disease, chronic viral hepatitis, liver cirrhosis, and chronic cholestatic liver disease. Moreover, these conditions are also associated with low bone mineral density (BMD) and greater fracture risk, particularly in cortical bone sites. Hence, we addressed whether disruptions in the GH/IGF-1 axis were causally related to the low bone mass in states of chronic liver disease using a mouse model of liver-specific GH-receptor (GHR) gene deletion (Li-GHRKO). These mice exhibit chronic hepatic steatosis, local inflammation, and reduced BMD. We then employed a crossing strategy to restore liver production of IGF-1 via hepatic IGF-1 transgene (HIT). The resultant Li-GHRKO-HIT mouse model allowed us to dissect the roles of liver-derived IGF-1 in the pathogenesis of osteodystrophy during liver disease. We found that hepatic IGF-1 restored cortical bone acquisition, microarchitecture, and mechanical properties during growth in Li-GHRKO-HIT mice, which was maintained during aging. However, trabecular bone volume was not restored in the Li-GHRKO-HIT mice. We found increased bone resorption indices in vivo as well as increased basal reactive oxygen species and increased mitochondrial stress in osteoblast cultures from Li-GHRKO and the Li-GHRKO-HIT compared with control mice. Changes in systemic markers such as inflammatory cytokines, osteoprotegerin, osteopontin, parathyroid hormone, osteocalcin, or carboxy-terminal collagen cross-links could not fully account for the diminished trabecular bone in the Li-GHRKO-HIT mice. Thus, the reduced serum IGF-1 associated with hepatic osteodystrophy is a main determinant of low cortical but not trabecular bone mass. © 2017 American Society for Bone and Mineral Research.

Abnormally High and Heterogeneous Bone Matrix Mineralization After Childhood Solid Organ Transplantation: A Complex Pathology of Low Bone Turnover and Local Defects in Mineralization

Chronic renal, liver, and heart failure in children associates with multiple skeletal complications. Increased fracture incidence often persists after transplantation and could be related to alterations in bone material properties. In the present cohort study we evaluated bone mineralization density distribution (BMDD) by quantitative backscattered electron imaging (qBEI) in 23 pediatric solid organ allograft recipients with suspected osteoporosis. We measured BMDD in the entire cross-sectional area of transiliac bone biopsies obtained from kidney (n = 9), liver (n = 9), and heart (n = 5) transplant recipients (aged 7.6 to 19.7 years; 6.0 ± 5.6 years posttransplantation, patients with a history of clinical fractures: n = 14). The BMDD findings were compared with age-appropriate references and with a previously presented cohort of children with chronic kidney disease on dialysis (CKD5D, n = 18). Furthermore, we related the BMDD parameters with patients' clinical and bone histomorphometric outcomes. Compared to healthy children, qBEI results for cancellous and cortical bone in transplant recipients revealed an increase in the most frequently occurring calcium concentration (+2.9%, p = 0.001; +3.5%, p = 0.014), in the portion of fully mineralized bone (fivefold; 10-fold, both p < 0.0001) and in heterogeneity of mineralization (+26,5% and +27.8%, both p < 0.0001), respectively. Moreover, the BMDD parameters were nonsignificantly distinct from CKD5D cohort except that the heterogeneity in mineralization was higher posttransplantation. There was a strong inverse correlation between the average calcium content of the bone matrix and patients' biochemical ALP levels, histomorphometric indices of bone formation and resorption. The abnormally high bone matrix mineralization in transplant recipients, consistent with serum and histomorphometric outcomes, suggests a history of low bone turnover with accumulation of fully mineralized bone packets. Additionally, the increased heterogeneity of mineralization suggests local alterations in mineralization kinetics, which may be linked to dysfunctional osteocytes that were recently shown to accumulate within the bone matrix during organ failure and concomitant glucocorticoid and immunosuppressive medication. © 2017 American Society for Bone and Mineral Research.

Bone health in children and adolescents with chronic diseases that may affect the skeleton: the 2013 ISCD Pediatric Official Positions

The aim of this Task Force was to review the use of dual-energy X-ray absorptiometry (DXA) in children and adolescents with underlying chronic diseases that pose risk factors for compromised bone health, such as inflammation, glucocorticoid therapy, or decreased mobility. The Task Force systematically analyzed more than 270 studies, with an emphasis on those published in the interval since the original 2007 Position Statements. Important developments over this period included prospective cohort studies demonstrating that DXA measures of areal bone mineral density (aBMD) predicted incident fractures and the development of robust reference data and strategies to adjust for bone size in children with growth impairment. In this report, we summarize the current literature on the relationship between DXA-based aBMD and both fracture (vertebral and non-vertebral) outcomes and non-fracture risk factors (e.g., disease characteristics, ambulatory status, and glucocorticoid exposure) in children with chronic illnesses. Most publications described the aBMD profile of children with underlying diseases, as well as the cross-sectional or longitudinal relationship between aBMD and clinically relevant non-fracture outcomes. Studies that addressed the relationship between aBMD and prevalent or incident fractures in children with chronic illnesses are now emerging. In view of these updated data, this report provides guidelines for the use of DXA-based aBMD in this setting. The initial recommendation that DXA is part of a comprehensive skeletal healthy assessment in patients with increased risk of fracture is unchanged. Although the prior guidelines recommended DXA assessment in children with chronic diseases at the time of clinical presentation with ongoing monitoring, this revised Position Statement focuses on the performance of DXA when the patient may benefit from interventions to decrease their elevated risk of a clinically significant fracture and when the DXA results will influence that management.

Bone metabolism in cholestatic children before and after living-related liver transplantation--a long-term prospective study

Bone disorders are common in children with end-stage liver diseases, especially those associated with cholestasis. Abnormal hepatocyte function, disordered vitamin D metabolism and calcium-phosphorous homeostasis, malnutrition, and immunosuppressive treatment are potential risk factors of bone tissue pathology before and after transplantation. The aim of the study was to analyze the long-term effect of successful living-related liver transplantation (LRLTx) on skeletal status and bone metabolism in cholestatic children. Eighteen cholestatic children (1.4±0.5yr old; 12 females [F]/6 males [M]) qualified for LRLTx were analyzed; 16 (5F/11M) of them participated in long-term observation (V4). Serum levels of osteocalcin (OC), procollagen type 1 N-terminal propeptide (P1NP), cross-linked telopeptide of type 1 collagen (CTx), insulin-like growth factor I (IGF-I), IGF-I binding protein 3 (IGFBP-3), parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), and 1,25-dihydroxyvitamin D (1,25(OH)(2)D) were assayed before (V0) and 6mo (V1), 12mo (V2), 18mo (V3), and 4.4yr (V4) after LRLTx. Total body bone mineral content (TBBMC) and total body bone mineral density (TBBMD) were measured by dual-energy X-ray absorptiometry (DXA) at the same pattern. Before LRLTx, the OC, P1NP, CTx, IGF-I, and IGFBP-3 levels as well as TBBMC and TBBMD were decreased compared with age-matched control group. The mean serum levels of 25(OH)D and 1,25(OH)(2)D were within reference ranges from V0 to V4. After LRLTx, the OC, P1NP, CTx, IGF-I, and IGFBP-3 as well as TBBMC and TBBMD reached the age-matched reference values. At V4, the level of P1NP decreased below and the PTH increased above the reference range that coincided with reduced Z-scores of both TBBMC (-1.11±1.24) and TBBMD (-1.00±1.19). P1NP and CTx, both measured at V3, correlated with IGF-I at V2 (R=0.86, p=0.014 and R=0.78, p=0.021, respectively) and PTH at V3 for P1NP and V1 for CTx (R=0.64, p=0.048 and R=0.54, p=0.038, respectively). The TBBMC changes between V0 and V4 correlated with IGF-I (R=0.68, p=0.015) and 1,25(OH)(2)D (R=0.54, p=0.025), both assayed at V1. The change of TBBMC Z-scores between V0 and V4 correlated with P1NP at V1 (R=0.69, p=0.002). The TBBMD changes between V0 and V4 correlated with CTx at V1 (R=0.54, p=0.027) and P1NP change between V0 and V1 (R=0.51, p=0.038). In short-term observation, successful LRLTx led to bone metabolism normalization triggered by probable anabolic action of IGF-I and PTH and manifested by TBBMC and TBBMD increases. In long-term horizon, moderately impaired DXA assessed bone status coincided with disturbances in bone metabolism. Bone metabolism markers, especially P1NP and CTx, appeared to be good predictors of changes in bone status evaluated by DXA.

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

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

Corticosteroid exposure not associated with long-term bone mineral density in pediatric liver transplantation

OBJECTIVES

The aim of the study was to examine the association of corticosteroid exposure and other skeletal risk factors with bone mineral density (BMD) and fractures following pediatric liver transplantation (LT) at a large single center.

PATIENTS AND METHODS

Lumbar spine BMD, measured using dual-energy x-ray absorptiometry (DXA), was corrected for bone age in 52 ambulatory children ages 4 to 18 years, at least 1 year post-LT. Potential risk factors for skeletal health such as corticosteroid exposure, dietary and lifestyle factors, and growth and fracture occurrence, were related to BMD using univariate and multivariate regression analyses.

RESULTS

The prevalence of low BMD (z score <-2) and post-LT fractures was 3 of 52 (5.8%) and 11 of 52 (21%), respectively. Univariate analysis revealed age >10 years at LT and body mass index (BMI) < 85th percentile at time of DXA were significantly associated with BMD (both P = 0.02). BMD did not correlate with corticosteroid dosage in the first year post-LT, the year before DXA or cumulative lifetime exposure. A cholestatic primary LT indication, acute rejection episodes, and fractures post-LT were not associated with BMD. Extracurricular physical activity, vitamin D, and calcium intake were not associated with BMD or fractures. Multivariate linear regression revealed increased time post-LT (P = 0.04) and higher BMI z score at time of DXA (P = 0.02) as the strongest independent variables associated with greater BMD.

CONCLUSIONS

Neither corticosteroid exposure nor a cholestatic primary indication for LT influenced BMD, which was largely normal in this ambulatory group. Children and adolescents undergoing LT after the age of 10 years and those with low BMI post-LT may be at greatest risk of poor skeletal health later in life, and thus a potential target patient population to benefit from preventive interventions.

Role of nutrition in pediatric chronic liver disease

The liver plays a central role in energy and nutrient metabolism. Malnutrition is highly prevalent among patients with chronic liver disease and leads to increased morbidity and mortality rates. This review addresses the causes of malnutrition, methods used to assess nutrition status, and appropriate treatment strategies in pediatric patients with chronic liver disease.

Living-related liver transplantation for siblings with progressive familial intrahepatic cholestasis 2, with novel genetic findings

Progressive familial intrahepatic cholestasis is a syndrome of severe cholestasis progressing to biliary cirrhosis and liver failure that develops in childhood. This report describes two siblings with PFIC-2 who underwent living-related liver transplantation from their genetically proven heterozygous parents. Both patients had normal gamma-glutamyl transpeptidase levels, but showed severe pruritus with sleep disturbance, cholestasis, jaundice and growth failure. Genetic testing of each patient revealed two missense mutations of the bile salt export pump, S901R and C1083Y, which have not previously been associated with PFIC-2. Usual medical treatment failed to improve their clinical symptoms, and the two siblings underwent living-related liver transplantation from their heterozygous parents. The transplants improved their clinical symptoms significantly, and the patients have since shown age-appropriate growth. Electron microscopic findings of the explanted liver of the younger sister revealed dense and amorphous bile, which is characteristic of PFIC-2. In the cases presented here, living-related liver transplantation from a heterozygous donor was associated with better quality of life and improvement of growth, and thus appears to be a feasible option for PFIC-2 patients. Mutation analysis is a useful tool to help decide the course of treatment of PFIC.

Optimizing nutritional management in children with chronic liver disease

Malnutrition is common in infants and children with chronic liver disease (CLD) and may easily be underestimated by clinical appearance alone. The cause of malnutrition in CLD is multifactorial, although insufficient dietary intake is probably the most important factor and is correctable. Fat malabsorption occurs in cholestatic disorders, and one must also consider any accompanying fat-soluble vitamin and essential fatty acid deficiencies. The clinician should proactively evaluate, treat, and re-evaluate response to treatment of nutritional deficiencies. Because a better nutritional state is associated with better survival before and after liver transplantation, aggressive nutritional management is an important part of the care of these children.

Dual-energy X-ray aborptiometry assessment in children and adolescents with diseases that may affect the skeleton: the 2007 ISCD Pediatric Official Positions

The Task Force focusing on the use of dual energy X-ray absorptiometry (DXA) in children and adolescents with diseases that may affect the skeleton reviewed over 300 articles to establish the basis for the Official Positions. A significant number of studies used DXA-based outcome measures to assess the effects of specific interventions and charted the natural history of incremental changes in bone size and mass in specific disease states in children. However, the utility of DXA in clinical practice has not been evaluated systematically, in large part due to the lack of a workable definition for childhood osteoporosis. Thus, in combination with the Official Positions addressing the diagnosis of osteoporosis in children, and the reporting of DXA results in children, this document presents clear guidelines from which clinicians and researchers alike can work. This report delineates a set of disorders in which it is appropriate to use DXA as part of the comprehensive assessment of skeletal health in children and adolescents, and provides guidance concerning the initiation of assessment and the frequency of monitoring. Importantly, this document also highlights significant gaps in our knowledge, emphasizing areas for future research.

Growth and final height after liver transplantation during childhood

OBJECTIVE

To evaluate the effect of end-stage pediatric liver disease and liver transplantation on growth and final height.

PATIENTS AND METHODS

We evaluated growth at 2 years (n = 101) and 5 years (n = 63) after pediatric liver transplantation (LTx). Twenty-three children reached final height. Height was expressed as a standard deviation score of the target height (zTH score) of each patient.

RESULTS

At the first 2 years after LTx, the zTH score was significantly increased from -1.7 to -1.3 SD (P < 0.05). Growth at 2 or 5 years after LTx, expressed as DeltazTH score, was positively correlated with pretransplant growth retardation (P < 0.05). In comparison with patients with noncholestatic primary liver disease, patients with cholestatic primary liver disease were more severely growth retarded before LTx (zTH score -2.0 vs -1.2 SD, P < 0.05) and had better growth in the first 2 years after LTx (DeltazTH score +0.6 vs -0.1 SD, P < 0.05). Twelve of the 23 patients had a final height below -1.3 SD of their target height.

CONCLUSIONS

Growth retardation is common in children before LTx, particularly in children with an underlying cholestatic disease. After LTx, catch-up growth was partial and was prominent only in cholestatic children who had been severely growth retarded before LTx. After LTx during childhood, approximately 50% of patients reach a final height lower than -1.3 SD of their genetic potential.

Bone mineral density of children with Wilson disease: efficacy of penicillamine and zinc therapy

OBJECTIVES

Osteoporosis accompanying chronic liver disease is well known; however, the exact prevalence is unknown. No data on bone mineral density (BMD) of children with Wilson disease (WD) have been published so far. In this study, we aimed to investigate the prevalence of osteoporosis in childhood WD and to observe the probable positive effects of penicillamine and zinc therapy on osteoporosis.

METHODS

Thirty-one children with newly diagnosed WD and sex and age-matched 16 healthy children were included. Mean age was 9.0+/-3.2 years (2 to 16 y). Bone mineral content (BMC) and BMD were measured on admission and in 13 cases they were reassessed after 1 year of treatment with penicillamine and zinc.

RESULTS

Mean BMD, BMC, and Z scores of the patients were significantly lower than those of healthy children: 0.52+/-0.09 versus 0.72+/-0.09 (P=0.001), 19.27+/-13.01 versus 29.67+/-14.23 (P=0.009), and -2.33+/-1.28 versus -0.12+/-0.31 (P=0.001), respectively. The prevalence of osteopenia and osteoporosis in children with WD was found as 22.6% and 67.7%, respectively. BMD and BMC levels were higher in children with neurologic involvement. The severity of the disease had no effect on the mentioned parameters. One year under treatment with penicillamine and zinc did not significantly alter the mentioned parameters.

CONCLUSIONS

In this first study investigating the prevalence of osteoporosis in children with WD, we found an extremely high prevalence. Because of nonbeneficial effect of routine treatment of WD on osteoporosis, we emphasize the necessity of screening of bone mineralization and additional therapeutic approach for those children.

Impaired bone health in adolescents after liver transplantation

Long-term complications related to immunosuppressive medication are an important problem after liver transplantation (OLT). This study was carried out to evaluate the bone health and risk factors for osteoporosis and fractures in 40 pediatric liver transplant recipients. The results of 208 longitudinal bone mineral density (BMD) measurements were analyzed retrospectively. In addition, a dual-energy X-ray absorptiometry was performed to assess the bone mineral content more precisely and to detect subclinical vertebral fractures (VF). The median age of the patients was 14 years and mean postoperative follow-up 7.0 years. The results showed that over half (58%) had lumbar spine (LS) Z-score </=-1.0 and one-fifth (18%) had asymptomatic VF. LS Z-score tended to increase from the first year after OLT, but during puberty the bone mass gain was suboptimal and Z-scores decreased in some subjects. Patients with VF were older at the time of OLT (p = 0.002) and their LS Z-score was lower (p = 0.001). Children transplanted before 10 years of age had less VF (p = 0.004) and higher LS Z-score (p = 0.005) than older patients. In conclusion, adolescent liver recipients are prone to osteoporosis and prevention should be targeted especially to this age group.

Growth curves of pediatric patients with biliary atresia following living donor liver transplantation: factors that influence post-transplantation growth

We evaluated the growth curves of children with BA after LDLT, and identified factors influencing growth velocity one-yr after LDLT (DeltaZ). The clinical data of 51 children with BA, who had an LDLT at our center from 2001 to 2005, were retrospectively reviewed. The Z scores for height and weight, and DeltaZ were studied. The correlation between DeltaZ and various clinical factors was evaluated statistically. Multivariate stepwise analyses were performed for DeltaZ. The average height and weight Z scores at the time of LDLT were -1.34 +/- 1.36 (+/-s.d.) and -0.78 +/- 1.15, respectively. Among 30 BA recipients with stable liver function after transplant, weight returned to normal one-yr post-transplantation. However, height did not return to normal even by the third post-transplantation year. On multivariate analyses, 73% of the variance in height DeltaZ could be accounted for by factors such as standardized height at the time of LDLT (proportion of variance: 38%), number of steroid pulse treatments (17%), donor age (10%), and the presence of HVS (9%). Fifty-four percentage of the variance in weight DeltaZ could be accounted for by factors such as standardized weight at the time of LDLT (37%) and the total steroid dose given (17%). Height and weight status at the time of LDLT likely have the strongest impact on DeltaZ. Additional factors include steroid exposure, age of the living donor, and presence of HVS, all of which should be considered to improve post-transplantation growth.

Impairment of bone mass development in children with chronic cholestatic liver disease

OBJECTIVE

To analyse aspects of mineral metabolism, bone mineral density (BMD), bone remodelling activity and serum IGF-1 levels in children with chronic cholestatic disease (CCLD).

PATIENTS AND MEASUREMENTS

A total of 13 children with chronic cholestatic liver disease (CCLD; mean age 7.2 +/- 4.8 years) and 22 control subjects (mean age 7.6 +/- 4.5 years) were studied. Serum osteocalcin, bone alkaline phosphatase (BAP), 25-hydroxyvitamin D, PTH and IGF-1 levels and urinary deoxypyridinoline were determined. BMD was measured by dual-energy X-ray absorptiometry in the lumbar spine, total hip and whole body. Lumbar spine areal BMD was converted mathematically to apparent volumetric BMD (aBMD) and corrected for the bone age of the patient.

RESULTS

Z-score of lumbar spine BMD was lower in CCLD patients than in controls and the difference was maintained when BMD was expressed as aBMD (control = 0.107 +/- 0.02 vs. CCLD = 0.092 +/- 0.02 g/cm(3), P < 0.05) and after conversion for bone age. All participants showed normal 25-hydroxyvitamin D levels, with no significant differences in serum levels of 25-hydroxyvitamin D and PTH between groups. IGF-1 levels were significantly lower in the CCLD group (control = 19.6 +/- 16.8 vs. CCLD = 6.4 +/- 7.6 nmol/l, P < 0.05) and a positive correlation was observed between whole body BMD and IGF-1 in this group.

CONCLUSIONS

These results indicate that CCLD limits bone mass gain in children. A reduction in hepatic IGF-1 production might be responsible, at least in part, for the low bone mass of these patients.

Therapy Insight: orthopedic complications after solid organ transplantation in childhood

Several factors, such as immobilization, metabolic bone disease and immunosuppressive drugs, can compromise the quality of bone in children who have undergone solid organ transplantation. In contrast to adults, decreased bone mineral density has been reported in only a small proportion of pediatric transplant patients, and the relationship between low bone mineral density and fracture risk has not been established in children. Nevertheless, fractures, scoliosis, and joint and spinal degeneration are common in patients who received solid organ grafts as children. Avascular bone necrosis occurs infrequently in this patient population. Future studies should evaluate the effects of the underlying disease, transplantation and immunosuppression on the metabolism of bone and cartilage. On the basis of our own clinical experience and literature review, the growing spine of children who have received transplants should be continuously evaluated, and follow-up of bone mineral density is indicated. By contrast, routine MRI of the joints seems unnecessary.

Incidence and predictors of fractures in children after solid organ transplantation: a 5-year prospective, population-based study

In this population-based prospective follow-up study, children undergoing solid organ transplantation had a highly elevated risk for fractures: The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. Thus, screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.

INTRODUCTION

The incidence and predictors of fractures after solid organ transplantation are not well documented in the pediatric age group.

MATERIALS AND METHODS

A total of 196 children, which is 93% of patients surviving kidney, liver, and heart transplantation in our country, participated in a retrospective chart review at enrollment followed by a 5-year prospective follow-up study between January 1999 and December 2004. Hospital and medical records were reviewed. All children underwent clinical examinations and answered questionnaires concerning fracture history at the beginning and at the end of the prospective follow-up. Radiographs of the thoracic and lumbar spine were obtained. The fracture incidence was compared with data obtained from public health registries.

RESULTS

Seventy-five (38%) of the transplant patients suffered from a total of 166 fractures after organ transplantation. The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. The age- and sex-adjusted hazard ratios (95% CI) were 61.3 (40.7-92.4) for vertebral, 17.9 (8.96-35.8) for symptomatic vertebral, 0.99 (0.65-1.50) for nonvertebral, and 2.90 (2.25-3.73) for all fractures in the patients compared with the control population. In a multivariate analysis, older age (hazard ratio [95% CI]; 2.02 [1.07-3.83]), male sex (2.15 [1.22-3.81]), liver transplantation (1.78 [1.01-3.14]), and fractures before transplantation (2.02 [0.92-4.47]) were the most significant independent risk factors.

CONCLUSIONS

Children undergoing solid organ transplantation have a highly elevated risk for fractures. Screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.

Post-transplantation growth among pediatric recipients of liver transplantation

Improving a patient's quality-of-life (QOL) post-liver transplantation is of great importance. An aspect of improved QOL is the restoration of normal growth patterns in pediatric patients. To describe the post-transplantation growth patterns of 72 children included in the National Institute of Diabetes and Digestive and Kidney Diseases - Liver Transplantation Database (NIDDK-LTD), multilevel models were used, according to which children who waited more than a year for transplantation were smaller, compared with age and sex matched peers, at transplantation than children who waited less than a year while children who were growth retarded at transplantation experienced a larger yearly comparison height increase than children who were not growth retarded. The analysis also showed that boys older than 2 yr and younger than 13 yr at transplantation and girls older than 2 yr and younger than 11 yr at transplantation were significantly less growth retarded at transplantation than boys and girls under the age of 2 yr at transplantation.

Effect of liver transplantation on multiple bone fractures in an infant with end-stage biliary atresia: a case report

Osteodystrophy is frequently found in children with chronic cholestatic liver disease. We herein report an end-stage case of biliary atresia that was associated with multiple bone fractures and severe growth retardation. The patient, an 8-month-old female, underwent a living-related liver transplantation and thereafter showed a dramatic improvement in growth and decrease in bone fractures. A correction of the liver function is therefore considered to be a key factor in treating osteodystrophy that is related to chronic cholestatic liver disease. It is also essential to perform liver transplantation at the most appropriate time to enhance and support the growth of these patients.

Current advances in bone health of disabled children

PURPOSE OF REVIEW

Bone health is now recognized to contribute to overall lifetime management of children, adolescents, and adults with disabling conditions including physical and intellectual disability and with many chronic disease processes. Such disorders have multiple components, with aspects of care covering a wide number of specialist practices. This review will highlight advances in understanding the nature of bone mass accumulation through childhood and adolescence, the impingement of a spectrum of chronic and disabling diseases and their treatments on bone, and will address current approaches to interpretation of bone mass in the growing skeleton and interventional strategies for improving outcomes for this group.

RECENT FINDINGS

Increased skeletal fragility in the disabled child is well recognized. Insights into the contributions of skeletal size and bone strength in males and females have altered interpretation of data, allowing a new focus on determinants of future bone health, particularly with regard to the contributions of growth and puberty. Strategies to address bone health including public and medical education concerning consumption of calcium, appropriate selection of vitamin D preparations, pubertal contribution to phases of growth and possible specialist use of newer drugs, such as bisphosphonates where indicated, are changing the outlook for this large group.

SUMMARY

Implications of these changed understandings provide a new focus on maximizing bone mass accumulation by the end of adolescence within the constraints of what is possible to achieve for an individual and for provision of an holistic approach to bone health.

Osseous complications of pediatric transplantation

Adult stature and peak bone mass are achieved through childhood growth and development. Multiple factors impair this process in children undergoing solid organ transplantation, including chronic illness, pretransplant osteodystrophy, use of medications with negative impact on bone, and post-transplant renal dysfunction. While growth delay and short stature remain common, the most severe forms of transplant-related bone disease, fracture and avascular necrosis, appear to have become less common in the pediatric age group. Osteopenia is very prevalent in adult transplant recipients and probably also in pediatrics, but its occurrence and sequelae are difficult to study in these groups due to methodological shortfalls of planar densitometry related to short stature and altered patterns of growth and development. Although the effect on lifetime peak bone mass is not clear, data from adult populations suggest an elevated long-term risk of bone disease in children receiving transplants. Optimal management of pretransplantation osteodystrophy, attention to post-transplant renal insufficiency among both renal and non-renal transplant patients, reduction of steroid dose in select patients, and supplementation with calcium plus vitamin D during expected periods of maximal bone loss may improve bone health. Careful research is required to determine the role of bisphosphonate therapy in pediatric transplantation.