Changes in branched-chain amino acids in an infant with maple syrup urine disease during perioperative pediatric liver transplant: A case report

An 11-month-old female infant diagnosed with classic subtype IB maple syrup urine disease underwent living donor liver transplantation. Blood samples for plasma amino acid analysis were collected during the three phases of the operation. Despite the perioperative prophylactic administration of 12.5% hypertonic dextrose solution with insulin and a 20% intralipid emulsion, the blood levels of the branched-chain amino acids increased dramatically during surgery, consistent with an acute intraoperative metabolic decompensation. However, these blood levels normalized soon after liver transplantation with an excellent outcome. We suggest that the occurrence of an intraoperative metabolic crisis during liver transplantation is not necessarily a sign of graft failure.

Domino liver transplantation for maple syrup urine disease in children: A single-center case series

BACKGROUND

Domino liver transplant (DLT) represents another type of liver donor to expand the donor pool. Recent reports of successful DLT in children with maple syrup urine disease (MSUD) show promising long-term outcomes.

METHODS

It was a retrospective study. All children with MSUD were paired with either recipients with end-stage liver disease (ESLD) or non-MSUD metabolic disease. Each pair underwent simultaneous liver transplant (LT), where the MSUD recipient received the graft from a living-related donor and the liver explanted from the MSUD donor was transplanted to the respective paired domino recipient. We report our experience regarding the techniques and outcomes of DLT at our center.

RESULTS

Eleven children with MSUD and 12 respective DLT recipients were enrolled, one of which was domino split-liver transplantation. DLT recipients included seven ESLD, two propionic acidemia (PA), one glycogen storage disease(GSD) type-1, one GSD type-3, and one Citrullinemia. Post-LT ICU and hospital stays were comparable (p > .05). Patient and graft survival was 100% and 66.6% in the MSUD group and DLT recipients at a mean follow-up of 13.5 and 15 months. There was no death in the MSUD group as compared to four in the DLT group. The amino acid levels rapidly normalized after the LT in the children with MSUD and they tolerated the normal unrestricted diet. No vascular, biliary, or graft-related complications were seen in the post-transplant period. No occurrence of MSUD was noted in DLT recipients.

CONCLUSION

DLTs have excellent post-surgical outcomes. DLT should be strongly considered and adopted by transplant programs worldwide to circumvent organ shortage.

Living Donor-Initiated Domino Split-Liver Transplantation in Pediatric Setup: A Case Report With Literature Review

BACKGROUND

In patients undergoing liver transplantation for metabolic diseases, removing the patient's liver for transplantation to another recipient is called "domino liver transplantation." The extracted liver can be divided and transplanted into 2 recipients, which is called domino split-liver transplantation in the literature. However, in our study, the domino liver was obtained from a pediatric patient.

METHODS

A patient with maple syrup urine disease (MSUD) underwent a living donor liver transplant, and the explanted liver was divided in situ into right and left lobes and transplanted to 2 separate patients. Demographic data, surgical techniques, postoperative period, and patient follow-ups were evaluated.

RESULTS

The father's left lobe liver graft was transplanted into a 12-year-old boy with MSUD. The removed liver was divided in situ into right and left lobes. The left lobe was transplanted to a 14-year-old male patient, whereas the right lobe was transplanted to a 67-year-old male patient. The donor and the first recipient were discharged on postoperative days 5 and 22. The second pediatric patient who underwent domino split-left lobe transplantation was discharged on postoperative day 23. The adult patient who underwent domino split-right lobe transplantation died on postoperative day 12 owing to massive esophageal variceal bleeding.

CONCLUSION

Patients who underwent liver transplantation due to MSUD are among the best donor choices for domino liver transplantation. If the extracted liver has a sufficient volume and anatomic features for a split, it can be used in "selected cases."

The impact of liver transplantation on health-related quality of life in (acute) intoxication-type inborn errors of metabolism

Organic acidurias (OAs), urea-cycle disorders (UCDs), and maple syrup urine disease (MSUD) belong to the category of intoxication-type inborn errors of metabolism (IT-IEM). Liver transplantation (LTx) is increasingly utilized in IT-IEM. However, its impact has been mainly focused on clinical outcome measures and rarely on health-related quality of life (HRQoL). Aim of the study was to investigate the impact of LTx on HrQoL in IT-IEMs. This single center prospective study involved 32 patients (15 OA, 11 UCD, 6 MSUD; median age at LTx 3.0 years, range 0.8-26.0). HRQoL was assessed pre/post transplantation by PedsQL-General Module 4.0 and by MetabQoL 1.0, a specifically designed tool for IT-IEM. PedsQL highlighted significant post-LTx improvements in total and physical functioning in both patients' and parents' scores. According to age at transplantation (≤3 vs. >3 years), younger patients showed higher post-LTx scores on Physical (p = 0.03), Social (p < 0.001), and Total (p =0.007) functioning. MetabQoL confirmed significant post-LTx changes in Total and Physical functioning in both patients and parents scores (p ≤ 0.009). Differently from PedsQL, MetabQoL Mental (patients p = 0.013, parents p = 0.03) and Social scores (patients p = 0.02, parents p = 0.012) were significantly higher post-LTx. Significant improvements (p = 0.001-0.04) were also detected both in self- and proxy-reports for almost all MetabQoL subscales. This study shows the importance of assessing the impact of transplantation on HrQoL, a meaningful outcome reflecting patients' wellbeing. LTx is associated with significant improvements of HrQol in both self- and parent-reports. The comparison between PedsQL-GM and MetabQoL highlighted that MetabQoL demonstrated higher sensitivity in the assessment of disease-specific domains than the generic PedsQL tool.

Living related versus deceased donor liver transplantation for maple syrup urine disease

Maple syrup urine disease (MSUD) is an inherited disorder of branched chain ketoacid (BCKA) oxidation associated with episodic and chronic brain disease. Transplantation of liver from an unrelated deceased donor restores 9-13% whole-body BCKA oxidation capacity and stabilizes MSUD. Recent reports document encouraging short-term outcomes for MSUD patients who received a liver segment from mutation heterozygous living related donors (LRDT). To investigate effects of living related versus deceased unrelated grafts, we studied four Brazilian MSUD patients treated with LRDT who were followed for a mean 19 ± 12 postoperative months, and compared metabolic and clinical outcomes to 37 classical MSUD patients treated with deceased donor transplant. Patient and graft survival for LRDT were 100%. Three of 4 MSUD livers were successfully domino transplanted into non-MSUD subjects. Following LRDT, all subjects resumed a protein-unrestricted diet as mean plasma leucine decreased from 224 ± 306 μM to 143 ± 44 μM and allo-isoleucine decreased 91%. We observed no episodes of hyperleucinemia during 80 aggregate postoperative patient-months. Mean plasma leucine:isoleucine:valine concentration ratios were ~2:1:4 after deceased donor transplant compared to ~1:1:1.5 following LRDT, resulting in differences of predicted cerebral amino acid uptake. Mutant heterozygous liver segments effectively maintain steady-state BCAA and BCKA homeostasis on an unrestricted diet and during most catabolic states, but might have different metabolic effects than grafts from unrelated deceased donors. Neither living related nor deceased donor transplant affords complete protection from metabolic intoxication, but both strategies represent viable alternatives to nutritional management.

Nutrition management guideline for maple syrup urine disease: an evidence- and consensus-based approach

In an effort to increase harmonization of care and enable outcome studies, the Genetic Metabolic Dietitians International (GMDI) and the Southeast Regional Newborn Screening and Genetics Collaborative (SERC) are partnering to develop nutrition management guidelines for inherited metabolic disorders (IMD) using a model combining both evidence- and consensus-based methodology. The first guideline to be completed is for maple syrup urine disease (MSUD). This report describes the methodology used in its development: formulation of five research questions; review, critical appraisal and abstraction of peer-reviewed studies and unpublished practice literature; and expert input through Delphi surveys and a nominal group process. This report includes the summary statements for each research question and the nutrition management recommendations they generated. Each recommendation is followed by a standardized rating based on the strength of the evidence and consensus used. The application of technology to build the infrastructure for this project allowed transparency during development of this guideline and will be a foundation for future guidelines. Online open access of the full, published guideline allows utilization by health care providers, researchers, and collaborators who advise, advocate and care for individuals with MSUD and their families. There will be future updates as warranted by developments in research and clinical practice.

Elective liver transplantation for the treatment of classical maple syrup urine disease

An 8.5-year-old girl with classical maple syrup urine disease (MSUD) required liver transplantation for hypervitaminosis A and was effectively cured of MSUD over an 8-year clinical follow-up period. We developed a collaborative multidisciplinary effort to evaluate the effects of elective liver transplantation in 10 additional children (age range 1.9-20.5 years) with classical MSUD. Patients were transplanted with whole cadaveric livers under a protocol designed to optimize safe pre- and post-transplant management of MSUD. All patients are alive and well with normal allograft function after 106 months of follow-up in the index patient and a median follow-up period of 14 months (range 4-18 months) in the 10 remaining patients. Leucine, isoleucine and valine levels stabilized within 6 hours post-transplant and remained so on an unrestricted protein intake in all patients. Metabolic cure was documented as a sustained increase in weight-adjusted leucine tolerance, normalization of plasma concentration relationships among branched-chain and other essential and nonessential amino acids, and metabolic and clinical stability during protein loading and intercurrent illnesses. Costs and risks associated with surgery and immune suppression were similar to other pediatric liver transplant populations.

Liver transplantation in maple syrup urine disease

Maple syrup urine disease (MSUD) is an autosomal recessive disorder. Impaired activity of the branched-chain 2-oxoacid dehydrogenase complex (BCOA-DH) causes accumulation of branched-chain L-amino (BCAA) and 2-oxoacids (BCOA) which may exert neurotoxic effects. Treatment comprises dietary management with strictly reduced quantities of protein and BCAA as well as aggressive intervention during acute neonatal and subsequent metabolic complications. MSUD is regarded as a metabolic disorder with potentially favourable outcome when the patients are kept on a carefully supervised long-term therapy. Up to now, three MSUD patients, exhibiting the classical form of the disease, have received orthotopic whole liver transplantation (OLT). Liver replacement resulted in a clear increase in whole body BCOA-DH activity to at least the level of very mild MSUD variants. These patients no longer require protein restricted diets and the risk of metabolic decompensation during catabolic events is apparently abolished.

CONCLUSION

Considering the overall expenses, risks, and outcome, however, the benefit of OLT, even in the most severe form of MSUD, may not be significantly different from that of a classical strict dietary management. Thus, OLT appears not to represent a specific option in the treatment in MSUD.