Lipid profiles in pediatric thoracic transplant recipients are determined by their immunosuppressive regimens

Management of dyslipidemia in pediatric renal transplant recipients

Dyslipidemia after kidney transplantation is a common complication that has historically been underappreciated, especially in pediatric recipients. It is also a major modifiable risk factor for cardiovascular disease, a top cause of morbidity and mortality of transplant patients. While most knowledge about post-transplant dyslipidemia has been generated in adults, recommendations and treatment strategies also exist for children and are presented in this review. Awareness of these applicable guidelines and approaches is required, but not sufficient, for the reliable management of dyslipidemia in our patients, and additional needs and opportunities for comprehensive care in this area (e.g., quality improvement) are outlined.

Prospective evaluation of metabolic syndrome and its features in a single-center series of hematopoietic stem cell transplantation recipients

Available studies on metabolic syndrome (MS) after hematopoietic stem cell transplantation (HSCT) are retrospective with heterogeneous inclusion criteria, and little is known about the early post-transplant phase. In our prospective study, clinical and laboratory data were collected in 100 HSCT recipients, 48 allogeneic and 52 autologous, at baseline, at + 30, + 100 and + 360 days. At baseline, MS was observed in 24 patients, significantly associated with insulin resistance and leptin on multivariate analysis. At + 30, the diagnosis of MS was confirmed in 43 patients, significantly related to insulin resistance and allogeneic transplants. If the whole series was considered, patients with MS had significantly higher mortality from any cause. The baseline presence of any MS feature was a predictor of + 30 MS. Isolated occurrences of MS features were related to hyperleptinemia and hyperinsulinemia, except in the case of low HDL cholesterol, linked to adiponectin and resistin. Our data confirm that patients undergoing HSCT have a high prevalence of MS, with hyperleptinemia playing a major role. The early peak of new MS cases is primarily attributable to insulin resistance, notably but not exclusively immunosuppression-induced; the subsequent long-term increase in MS cases may be an effect of persistent adipokine imbalance.

Association Between Cytokines and Liver Histology in Children with Nonalcoholic Fatty Liver Disease

Background

Reliable non-invasive markers to characterize inflammation, hepatocellular ballooning, and fibrosis in nonalcoholic fatty liver disease (NAFLD) are lacking. We investigated the relationship between plasma cytokine levels and features of NAFLD histology to gain insight into cellular pathways driving NASH and to identify potential non-invasive discriminators of NAFLD severity and pattern.

Methods

Cytokines were measured from plasma obtained at enrollment in pediatric participants in NASH Clinical Research Network studies with liver biopsy-proven NAFLD. Cytokines were chosen a priori as possible discriminators of NASH and its components. Minimization of Akaike Information Criterion (AIC) was used to determine cytokines retained in multivariable models.

Results

Of 235 subjects, 31% had "Definite NASH" on liver histology, 43% had "Borderline NASH", and 25% had NAFLD but not NASH. Total plasminogen activator inhibitor 1 (PAI1) and activated PAI1 levels were higher in pediatric participants with Definite NASH and with lobular inflammation. Interleukin-8 (IL-8) was higher in those with stage 3-4 fibrosis and lobular inflammation. sIL-2rα was higher in children with stage 3-4 fibrosis and portal inflammation. In multivariable analysis, PAI1 variables were discriminators of Borderline/Definite NASH, definite NASH, lobular inflammation and ballooning. IL-8 increased with steatosis and fibrosis severity; sIL-2rα increased with fibrosis severity and portal inflammation. IL-7 decreased with portal inflammation and fibrosis severity.

Conclusions

Plasma cytokines associated with histology varied considerably among NASH features, suggesting promising avenues for investigation. Future, more targeted analysis is needed to identify the role of these markers in NAFLD and to evaluate their potential as non-invasive discriminators of disease severity.

Dyslipidemia after pediatric renal transplantation-The impact of immunosuppressive regimens

Dyslipidemia contributes to cardiovascular morbidity and mortality in pediatric transplant recipients. Data on prevalence and risk factors in pediatric cohorts are, however, scarce. We therefore determined the prevalence of dyslipidemia in 386 pediatric renal transplant recipients enrolled in the CERTAIN registry. Data were obtained before and during the first year after RTx to analyze possible non-modifiable and modifiable risk factors. The prevalence of dyslipidemia was 95% before engraftment and 88% at 1 year post-transplant. Low estimated glomerular filtration rate at 1 year post-transplant was associated with elevated serum triglyceride levels. The use of TAC and of MPA was associated with significantly lower concentrations of all lipid parameters compared to regimens containing CsA and mTORi. Immunosuppressive regimens consisting of CsA, MPA, and steroids as well as of CsA, mTORi, and steroids were associated with a three- and 25-fold (P<.001) increased risk of having more than one pathologic lipid parameter as compared to the use of TAC, MPA, and steroids. Thus, amelioration of the cardiovascular risk profile after pediatric RTx may be attained by adaption of the immunosuppressive regimen according to the individual risk profile.

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.

Strategies to prevent cellular rejection in pediatric heart transplant recipients

Despite more than 40 years' experience in pediatric heart transplantation, cellular rejection remains a significant cause of morbidity and mortality. In this review, strategies and agents to prevent acute cellular rejection are discussed. Strategies to prevent rejection are divided into two phases - induction and maintenance therapies. Currently, the most commonly used induction agents are polyclonal antibodies (rabbit or equine antithymocyte globulin) and interleukin-2 receptor antibodies (daclizumab or basiliximab). Induction therapies have reduced early rejection, are renal sparing, and can reduce corticosteroid exposure, but have not yet been shown to have a longer term survival benefit. Multiple maintenance immunosuppressants are available. Nearly all regimens include a calcineurin inhibitor (either ciclosporin [cyclosporine] or tacrolimus). Most combinations in pediatric heart transplantation include an antiproliferative agent (azathioprine, mycophenolate mofetil or, less commonly, sirolimus). Everolimus has seen increasing use in adult heart transplant patients in Europe but, to date, its use is rare in pediatric heart transplantation. The use of corticosteroids as a third agent is still common, but strategies to avoid or minimize their use are increasing. The 'best' combination of therapies varies between studies. By gaining a better understanding of individuals' genetic and environmental risk factors, we may in the future be able to better predict the course of cardiac allografts and enhance our ability to tailor immunosuppression to individual patient variables with the ultimate goal of inducing a state of immune tolerance.

Cure of multifocal panhepatic hepatoblastoma: is liver transplantation always necessary?

PURPOSE

Multifocal panhepatic hepatoblastoma (HB) without extrahepatic disease is generally considered as an indication for total hepatectomy and liver transplantation. However, after initial chemotherapy, downstaging of the tumor sometimes allows complete macroscopic resection by partial hepatectomy. This procedure is no longer recommended because of the risk of persistent viable tumor cells in the hepatic remnant. We report our experience with conservative surgery in such cases.

METHOD

Between 2000 and 2005, 4 children were consecutively referred to our unit with multinodular pan-hepatic HBs (classification PRETEXT IV of the International Society of Pediatric Oncology Liver Tumor Study Group SIOPEL). Three of them had extrahepatic disease at diagnosis. All patients were treated according to SIOPEL 3 and 4 protocols.

RESULTS

Extrahepatic metastases were still viable in 2 of 3 patients after initial chemotherapy. These patients eventually died of tumor recurrence. In the 2 patients without residual extrahepatic disease, liver tumors had regressed, and complete macroscopic excision of hepatic tumor remnants could be achieved by conservative surgery. These 2 children are alive and well and free of tumor 7 years after diagnosis.

CONCLUSIONS

Conservative surgery may be curative in some multinodular PRETEXT IV HB patients, with a good response to preoperative chemotherapy and complete excision of all macroscopic tumor remnants. However, because of the lack of reliable predictors of sterilization of the microscopic disease in the residual liver, with subsequent poor prognosis, total hepatectomy and liver transplantation remain currently recommended in patients with multinodular PRETEXT IV HB without extrahepatic disease, even though some of these children are probably overtreated.

Adverse effects of immunosuppression in pediatric solid organ transplantation

Solid organ transplantation is a life-saving treatment for end-stage organ failure in children. Immunosuppressant medications are used to prevent rejection of the organ transplant. However, these medications are associated with significant adverse effects that impact growth and development, quality of life (QOL), and sometimes long-term survival after transplantation. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. Early recognition of immunosuppressant adverse effects may help to reduce morbidities associated with solid organ transplantation, improve QOL, and possibly increase overall patient survival.

Tacrolimus in pediatric heart transplantation: ameliorated side effects in the steroid-free, statin era

Due to concerns over the side effects of cyclosporine, tacrolimus is widely used in pediatric heart transplantation. However, tacrolimus therapy is also accompanied by potentially serious side effects. This paper examines the side effect profile of tacrolimus in a large group of pediatric heart recipients. Data on renal function, diabetes, hyperlipidemia and hypertension were collected by case-note review of 100 patients who had received . OR = 12 months treatment with tacrolimus. Forty-two patients received tacrolimus from the time of transplant (de novo), and 58 were initially treated with cyclosporine (switch). Mean estimated glomerular filtration rate improved in the first six months post transplant in the de novo group (66.7-84.6 mL/min/1.73 m2, p = 0.002). Conversely, it decreased in those initially treated with cyclosporine (82.1-68.8, p = 0.032), but improved after switch to tacrolimus (77.3-85.6, p = 0.006). Twenty-one percent exhibited glucose intolerance, and 2% had diabetes. Borderline or elevated fasting cholesterol levels were present in 4.4%. Hypertension was seen in 67% at the point of switch from cyclosporine, which fell to 36% at latest follow-up (p = 0.001). These results present an encouraging outlook for this cohort of patients. The relatively low levels of complications shown may be due to early weaning of steroids, and concomitant statin therapy.

Ezetimibe in Heart Transplantation: Initial Experience

Dyslipidemia is a common problem among heart transplant (HT) recipients; it is a frequent risk factor in these patients that is exacerbated by immunosuppressive drugs. Statins are effective drugs to treat dyslipidemia in HT recipients, but control is suboptimal in some patients. Ezetimibe acts through inhibition of the enterohepatic recirculation, a mechanism different from but complementary to statins. Our objective was to assess the effect of the addition of ezetimibe to statin therapy among a population of HT patients.

PATIENTS AND METHODS

We included 19 stable patients on statin therapy with suboptimal control of cholesterol. Determinations were performed at baseline on statins and at 6 months (statins + ezetimibe). The analyzed variables were total cholesterol and fractions, triglycerides, cyclosporine levels, CPK, SGOT/SGPT, and bilirubin. The statistics were Student's t test for paired samples.

RESULTS

The overall mean age was 59 +/- 9 years with 95% males and mean BMI 27.5 +/- 3.5. The time since HT was 7 +/- 3 years. The reason for HT included ischemic heart disease in 68%. Pre-HT risk factors included in arterial hypertension in 32% and insulin-dependent diabetes mellitus in 10%, Dyslipidemia occurred in 68%; hypertriglyceridemia in 16% and hyperuricemia in 21%. Immunosuppression was cyclosporine in 100% and steroids in 94%. Type of lipid-lowering agent was simvastatin in 5%; pravastatin, 32%; atorvastatin, 58%; fibrates, 10%. The ezetimibe dose was 10 mg/day in 95% of cases. When ezetimibe was added we observed differences in total cholesterol values (total cholesterol at baseline: 279 +/- 74, total cholesterol with ezetimibe: 198 +/- 47 mg/dL; P = .0001) and LDL-cholesterol values (LDL-cholesterol at baseline: 171 +/- 69, LDL-cholesterol with ezetimibe: 109 +/- 41 mg/dL; P = .001). The remaining variables did not show significant differences.

CONCLUSION

The addition of ezetimibe to statin therapy among heart transplant patients was effective to control dyslipidemia and showed an excellent safety profile.

Advances in pediatric heart transplantation

PURPOSE OF REVIEW

Heart transplantation has become a reasonable treatment option for pediatric patients with end-stage heart failure or complex congenital cardiac defects not amenable to conventional surgical intervention. This review will summarize the current state of pediatric cardiac transplantation and review recent advances leading to new therapies.

RECENT FINDINGS

Improvements in early mortality after cardiac transplantation have occurred consistently over time since the 1980s, short-term survival rates are high, and most patients enjoy an excellent quality of life with minimal restrictions. The reduction of late mortality is still a major challenge, however, largely as a result of transplant-related coronary artery disease causing chronic graft failure and arrhythmogenic sudden death. Additional causes of morbidity and mortality occurring late after transplantation include renal dysfunction related to chronic immunosuppressive therapy with calcineurin inhibitors (tacrolimus or cyclosporine) and posttransplant lymphoproliferative disorders related to chronic immunosuppression. Newer agents (sirolimus, everolimus) have shown promise in immunosuppressive regimens that may alter the development or progression of long-term complications.

SUMMARY

New immunosuppressive agents allow alterations in drug regimens to minimize renal complications, and may influence the incidence and progression of transplant vasculopathy. Recent studies on posttransplant lymphoproliferative disorders should result in earlier diagnosis and therapy.

Heart and lung transplantation in children

During the past two decades, several advances have resulted in marked improvement in medium-term survival for infants and children undergoing heart transplantation. Unfortunately, progress has been less dramatic in the field of lung and heart-lung transplantation, where there is little evidence of improved outcomes. The procedures remain palliative and all transplant recipients are at risk for the adverse effects of non-specific immunosuppression, including infections, lymphoproliferative disorders, and non-lymphoid malignancies. In addition, current immunosuppressive agents have narrow therapeutic windows and exhibit a wide array of organ toxicities, posing special challenges for the young patient who must endure life-long immunosuppression. New immunosuppressive regimens have lowered the rates of acute rejection but appear to have had relatively little impact on the incidence of chronic rejection, the principal cause of late graft loss. The ultimate goal is to induce a state of donor-specific tolerance, wherein the recipient will accept the allograft indefinitely without the need for long-term immunosuppression. This quest is currently being realised in animal models of solid organ transplantation, and offers great hope for children undergoing heart and lung transplantation in the future.