Are children after liver transplant more prone to non-alcoholic fatty liver disease?

Imaging of late complications of cancer therapy in children

Long-term survival after childhood cancer has improved dramatically over recent decades but survivors face lifelong risks of adverse health effects. Many of these chronic conditions are a direct result of previous therapeutic exposures. Compared to their siblings, survivors face a greater than 8-fold increase in relative risk of severe or life-threatening medical conditions; the most significant of these include second malignancies and cardiovascular and pulmonary diseases. Imaging can play a key role in identifying and characterizing such complications, which can be reasonably predicted with knowledge of the child's treatment. This article highlights the varied radiologic presentations and features seen in late cancer-therapy-related conditions.

Long-term effect of childhood liver transplantation on body cell mass

Malnutrition is common in end-stage liver disease, but a correction after transplantation is expected. Body cell mass (BCM) assessment using total body potassium (TBK) measurements is considered the gold standard for assessing nutritional status. The aim of this study was to examine the BCM and, therefore, nutritional status of long-term survivors after childhood liver transplantation. This was a longitudinal nested cohort study of patients undergoing transplantation at <18 years of age and surviving >3 years with ongoing review at our center. TBK measurements were obtained before transplantation and during long-term follow-up. BCM was calculated from TBK and was adjusted for the height raised to power p, which depended on sex (BCM/height(p)). The effects of the age at transplant, linear growth impairment, a diagnosis of biliary atresia, and steroid use were assessed. Thirty-two patients (20 males) participated; 59% had biliary atresia. The median age at transplant was 2.11 years (range = 0.38-10.92 years). Posttransplant testing was performed at a median of 7.23 years (range = 3.28-14.99 years) when they were 10.12 years old (range = 4.56-20.77 years). This cohort attained mean z scores for height, weight, and body mass index of -0.41 ± 1.36, -0.26 ± 1.14, and 0.04 ± 0.99, respectively. BCM/height(p) was reduced before transplantation but was further reduced after transplantation (P < 0.001) despite the normalization of height and weight. Weight recovery, therefore, likely came from increased fat mass and not BCM. Linear growth impairment was associated with a greater reduction in posttransplant BCM/height(p) (P = 0.02). In multivariate analyses, only an older age at transplant predicted reduced posttransplant BCM/height(p) (P = 0.02). The age at transplant, sex, steroid use, and underlying diagnosis did not predict changes in BCM/height(p) after transplantation. In conclusion, weight recovery in long-term survivors of childhood liver transplantation is likely due to increased fat mass because BCM remains reduced. Nutritional compromise persists in long-term survivors of childhood liver transplantation.

Non-alcoholic fatty liver disease and liver transplantation: Outcomes and advances

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent causes of chronic liver disease worldwide. In the last decade it has become the third most common indication for liver transplantation in the United States. Increasing prevalence of NAFLD in the general population also poses a risk to organ donation, as allograft steatosis can be associated with non-function of the graft. Post-transplant survival is comparable between NAFLD and non-NAFLD causes of liver disease, although long term outcomes beyond 10 year are lacking. NAFLD can recur in the allograft frequently although thus far post transplant survival has not been impacted. De novo NAFLD can also occur in the allograft of patients transplanted for non-NAFLD liver disease. Predictors for NAFLD post-transplant recurrence include obesity, hyperlipidemia and diabetes as well as steroid dose after liver transplantation. A polymorphism in PNPLA3 that mediates triglyceride hydrolysis and is linked to pre-transplant risk of obesity and NAFLD has also been linked to post transplant NAFLD risk. Although immunosuppression side effects potentiate obesity and the metabolic syndrome, studies of immunosuppression modulation and trials of specific immunosuppression regimens post-transplant are lacking in this patient population. Based on pre-transplant data, sustained weight loss through diet and exercise is the most effective therapy for NAFLD. Other agents occasionally utilized in NAFLD prior to transplantation include vitamin E and insulin-sensitizing agents. Studies of these therapies are lacking in the post-transplant population. A multimodality and multidisciplinary approach to treatment should be utilized in management of post-transplant NAFLD.

Pediatric post-transplant metabolic syndrome: new clouds on the horizon

Liver transplantation (LT) is a standard treatment for children with end-stage liver disease, standing at more than 90% survival rate after one yr, and at over a 70% survival rate after five yr. The majority of transplanted children enjoy an excellent quality of life but complications can occur in the long term, and can develop subclinically in otherwise well children; there are various underestimated nutritional and metabolic aspects, including the so-called post-transplant metabolic syndrome (PTMS). During the post-transplant period, the use of immunosuppressants, corticosteroids, calcineurin inhibitors, and the presence of risk factors, including non-alcoholic fatty liver disease (NAFLD), and kidney and bone complications have been largely implicated in PTMS development. Strategies to reduce the progression of PMTS should include careful screening of patients for diabetes, dyslipidemia, and obesity, and to support weight reduction with a carefully constructed program, particularly based on diet modification and exercise. With early identification and appropriate and aggressive management, excellent long-term health outcomes and acceptable graft survival can be achieved.

Posttransplant metabolic syndrome in children and adolescents after liver transplantation: a systematic review

During long-term follow-up, 18% to 67% of pediatric liver transplant recipients are overweight or obese, with rates varying by age and pretransplant weight status. A similar prevalence of posttransplant obesity has been seen in adults. Adults also develop posttransplant metabolic syndrome and, consequently, cardiovascular disease at rates that exceed the rates in age- and sex-matched populations. Posttransplant metabolic syndrome has never been studied in pediatric liver transplant recipients, and this population is growing as transplant outcomes continue to improve. Here we systematically review the literature for each component of metabolic syndrome-obesity, hypertension, dyslipidemia, and glucose intolerance-in pediatric liver transplant recipients. Their rates of obesity are similar to the rates in children in the general U.S. population. However, hypertension, dyslipidemia, and diabetes are more common than would be expected in transplant recipients according to age, sex, and obesity severity. Immunosuppressive medications are major contributors. The limitations of previous studies, including heterogeneous methods of diagnosis, follow-up times, and immunosuppressive regimens, hinder the analysis of risk factors. Importantly, no studies have reported graft or patient outcomes associated with components of metabolic syndrome after pediatric liver transplantation. However, if the trends in children are similar to the trends seen in adults, these conditions may lead to significant long-term morbidity. Further research on the prevalence, causes, and consequences of posttransplant metabolic syndrome in pediatric liver transplant recipients is needed and will ultimately help to improve long-term outcomes.

Outcomes of 5-year survivors of pediatric liver transplantation: report on 461 children from a north american multicenter registry

OBJECTIVES

Although liver transplantation has been the standard of care therapy for life-threatening liver diseases for >20 years, data on the long-term impact of liver transplantation in children have been primarily limited to single-center experiences. The objective of this study was to characterize and evaluate the clinical course of children who have survived >or=5 years after pediatric liver transplantation in multiple centers across North America.

PATIENTS AND METHODS

Patients enrolled in the Studies of Pediatric Liver Transplantation database registry who had undergone liver transplantation at 1 of 45 pediatric centers between 1996 and 2001 and survived >5 years from liver transplantation were identified and their clinical courses retrospectively reviewed.

RESULTS

The first graft survival for 461 five-year survivors was 88%, with 55 (12%) and 10 (2%) children undergoing a second and third liver transplantation. At the 5-year anniversary clinic visit, liver function was preserved in the majority with daily use of immunosuppression therapy, including a calcineurin inhibitor and oral prednisone, reported by 97% and 25% of children, respectively. The probability of an episode of acute cellular rejection occurring within 5 years after liver transplantation was 60%. Chronic rejection occurred in 5% patients. Posttransplant lymphoproliferative disease was diagnosed in 6% children. Calculated glomerular filtration rate was <90 mL/minute per 1.73 m2 in 13% of 5-year survivors. Age- and gender-adjusted BMI>95th percentile was noted in 12%, with height below the 10th percentile in 29%.

CONCLUSIONS

Children who are 5-year survivors of liver transplantation have good graft function, but chronic medical conditions and posttransplantation complications affect extrahepatic organs. A comprehensive approach to the management of these patients' multiple unique needs requires the expertise and commitment of health care providers both beyond and within transplant centers to further optimize long-term outcomes for pediatric liver transplant recipients.