Impact of citrulline substitution on clinical outcome after liver transplantation in carbamoyl phosphate synthetase 1 and ornithine transcarbamylase deficiency

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

Application of graft-derived cell-free DNA in ornithine transcarbamylase deficiency patient after living donor liver transplantation: Two case reports

RATIONALE

Graft-derived-cell-free DNA (Gcf-DNA) in plasma was a promising biomarker to monitor graft-rejection after liver transplantation. However, little is known about the application of Gcf-DNA in living-donor-liver-transplantation (LDLT).

PATIENTS CONCERN

In this study, 2 patients diagnosed with Ornithine Transcarbamylase Deficiency (OTCD) were enrolled and indicated for LDLT.

DIAGNOSES

Two patients were genetically diagnosed with OTCD, and they suffered from recurrent and uncontrollable hyper-ammonemia and failed in accepting the normalized OTCD treatments, such as decreasing dietary nitrogen intake and increasing waste-nitrogen excretion.

INTERVENTIONS

LDLT was performed in the 2 patients uneventfully, and we collected circulating cell-free DNA from plasma in specific postoperative time points (day 1, day 7, day 14, day 30, day 60). Since both of the recipients were sex-mismatch with the donors, we measured Gcf-DNA through the Y-chromosome method and compared it with the routine liver function.

OUTCOMES

The result showed that Gcf-DNA had the similar discrimination of graft injury trend while compared to routine liver function. The follow-up showed these 2 patients' status is stable.

LESSONS

Applying Gcf-DNA to monitor graft injury in LDLT is promising, but still long term follow-up and more samples are needed for validation.

Balloon dilatation for treatment of hepatic venous outflow obstruction following pediatric liver transplantation

AIM

To assess the efficacy and safety of balloon dilatation for the treatment of hepatic venous outflow obstruction (HVOO) following pediatric liver transplantation.

METHODS

A total of 246 pediatric patients underwent liver transplantation at our hospital between June 2013 and September 2016. Among these patients, five were ultimately diagnosed with HVOO. Seven procedures (two patients underwent two balloon dilatation procedures) were included in this analysis. The demographic data, types of donor and liver transplant, interventional examination and therapeutic outcomes of these five children were analyzed. The median interval time between pediatric liver transplantation and balloon dilatation procedures was 9.8 mo (range: 1-32).

RESULTS

Five children with HVOO were successfully treated by balloon angioplasty without stent placement, with seven procedures performed for six stenotic lesions. All children underwent successful percutaneous intervention. Among these five patients, four were treated by single balloon angioplasty, and these patients did not develop recurrent stenosis. In seven episodes of balloon angioplasty across the stenosis, the pressure gradient was 12.0 ± 8.8 mmHg before balloon dilatation and 1.1 ± 1.5 mmHg after the procedures, which revealed a statistically significant reduction (P < 0.05). The overall technical success rate among these seven procedures was 100% (7/7), and clinical success was achieved in all five patients (100%). The patients were followed for 4-33 mo (median: 15 mo). No significant procedural complications or procedure-related deaths occurred.

CONCLUSION

Balloon dilatation is an effective and safe therapeutic option for HVOO in children undergoing pediatric liver transplantation. Venous angioplasty is also recommended in cases with recurrent HVOO.

Impact of enzyme activity assay on indication in liver transplantation for ornithine transcarbamylase deficiency

There are no objective and concrete guidelines for the management of Ornithine transcarbamylase deficiency (OTCD). Based on previous findings, we hypothesized that patients with OTCD have a low Ornithine transcarbamylase (OTC) activity in the liver, and therefore it would be better to determine the appropriate indications and optimal timing for liver transplantation (LT) based on the OTC activity. However, few data have so far been accumulated on the OTC activity in cases that are indicated for LT. The purpose of the present study was to clarify the OTC activity in cases that were indicated for LT. This study involved thirteen children with OTCD (8 males and 5 females) who underwent LT, and two females with OTCD who did not require LT. The OTC activity of the neonatal onset type ranged from 0% to 7.2%, while that of the late onset type who underwent LT ranged from 4.4% to 18.7%. The OTC activity of the late onset type which did not require LT was 33-38% based on a preoperative needle liver biopsy. Some late onset patients that underwent LT, showed an activity that was as low as that observed in the neonatal onset cases. This is the first report to show the results of measuring the OTC activity for serial OTCD cases indicated for LT. OTC activity might be an indicator to determine the indications for and the timing of LT in the late onset type, however, further investigations are necessary.

Improved quality of life and unchanged magnetic resonance brain imaging after living donor liver transplantation for late-onset ornithine transcarbamylase deficiency: report of a case

We report the case of a 7-year-old girl with ornithine transcarbamylase deficiency whose quality of life (QOL) improved greatly after a living donor liver transplantation (LDLT). Ornithine transcarbamylase deficiency had been diagnosed when she was 2 years old and she finally underwent LDLT, with her father as the donor, when she was 7 years old. The patient had suffered episodes of hyperammonemic encephalopathy ranging from lethargy to coma, treated by hemodialysis twice before LDLT, and her intelligence quotient was borderline for her age. Preoperative magnetic resonance imaging (MRI) showed an atrophic area in the subcortical white matter of the frontal lobe. After LDLT, the patient suffered acute rejection with hyperamylasemia, but not hyperammonemia. Postoperative MRI and quantitative MR spectroscopy showed no changes in the subcortical lesion. She has been followed up carefully for 16 months and has had no further complications or any sign of hyperammonemia.

Current role of liver transplantation for the treatment of urea cycle disorders: a review of the worldwide English literature and 13 cases at Kyoto University

To address the current role of liver transplantation (LT) for urea cycle disorders (UCDs), we reviewed the worldwide English literature on the outcomes of LT for UCD as well as 13 of our own cases of living donor liver transplantation (LDLT) for UCD. The total number of cases was 51, including our 13 cases. The overall cumulative patient survival rate is presumed to be more than 90% at 5 years. Most of the surviving patients under consideration are currently doing well with satisfactory quality of life. One advantage of LDLT over deceased donor liver transplantation (DDLT) is the opportunity to schedule surgery, which beneficially affects neurological consequences. Auxiliary partial orthotopic liver transplantation (APOLT) is no longer considered significant for the establishment of gene therapies or hepatocyte transplantation but plays a significant role in improving living liver donor safety; this is achieved by reducing the extent of the hepatectomy, which avoids right liver donation. Employing heterozygous carriers of the UCDs as donors in LDLT was generally acceptable. However, male hemizygotes with ornithine transcarbamylase deficiency (OTCD) must be excluded from donor candidacy because of the potential risk of sudden-onset fatal hyperammonemia. Given this possibility as well as the necessity of identifying heterozygotes for other disorders, enzymatic and/or genetic assays of the liver tissues in cases of UCDs are essential to elucidate the impact of using heterozygous carrier donors on the risk or safety of LDLT donor-recipient pairs. In conclusion, LT should be considered to be the definitive treatment for UCDs at this stage, although some issues remain unresolved.

Acute promyelocytic leukemia after living donor partial orthotopic liver transplantation in two Japanese girls

Organ transplant recipients are generally considered to be at greater risk for developing malignant disorders because of prolonged immunosuppression for organ grafting, but acute leukemia is a rare complication after organ transplantation (0.2 -2.5%). We encountered two girls with acute promyelocytic leukemia (APL) after living donor partial orthotopic liver transplantation. In one patient, APL developed 21 months after liver transplantation for ornithine transcarbamylase deficiency. She had been administered tacrolimus for prophylaxis of graft-versus-host reaction. In the other patient, APL was diagnosed 46 months after liver transplantation for congenital biliary atresia. Both patients were successfully treated by chemotherapy including all-trans retinoic acid (ATRA), and after reaching complete remission, they have subsequently been in continuous remission. Although leukemia after liver transplantation is generally thought of as a rare complication, increases in survival rate following liver transplantation is likely to lead to more such cases, and documentation of these cases is therefore of importance.

Viral infections and prolonged fever after liver transplantation in young children with inborn errors of metabolism

BACKGROUND AND PURPOSE

Liver transplantation could be a useful treatment for selected inborn errors of metabolism. This study evaluated the outcome and viral infections after liver transplantation in young children and infants with these diseases.

METHODS

The outcome of liver transplantation and clinical characteristics of the following 4 patients were assessed: 1 infant with ornithine transcarbamylase deficiency (OTCD) who received liver transplant aged 3 years and 4 months; 1 infant with carbamyl phosphate synthetase I deficiency (CPSID) who received liver transplant at 14 months of age; and 2 infants with methylmalonic acidemia (MMA) who received liver transplant at 8 months and 11 months of age, respectively. All donors, except the 8-month-old infant with MMA, showed serologic evidence of previous cytomegalovirus (CMV) infection before transplantation. All 4 of these donors showed serologic evidence of previous infection of Epstein-Barr virus (EBV). None of the recipients had previous CMV infection. Both the infant with OTCD and the 8-month-old infant with MMA had previous EBV infection, while the other 2 patients did not. Preoperative hemodialysis was performed in both infants with MMA. Postoperative follow-up included metabolic stability, disability degree, and viral infections.

RESULTS

None of the patients developed severe metabolic decompensation after transplantation and all increased protein intake postoperatively. Symptomatic viral infections, however, were present in all patients postoperatively, including CMV infection in the infant with OTCD and the 11-month-old infant with MMA, reactivation of EBV infection in the infant with OTCD and the 8-month-old infant with MMA, and primary EBV infection in the infant with CPSID.

CONCLUSIONS

Liver transplantation was an effective treatment for all 4 of these patients with inborn errors of metabolism. The risk of symptomatic viral infections for these patients was high. This was likely associated with conditions including immunosuppression, young age, endemic nature of CMV and EBV infections, and lack of CMV prophylaxis.

Developmental outcomes with early orthotopic liver transplantation for infants with neonatal-onset urea cycle defects and a female patient with late-onset ornithine transcarbamylase deficiency

Urea cycle defects (UCDs) typically present with hyperammonemia, the duration and peak levels of which are directly related to the neurologic outcome. Liver transplantation can cure the underlying defect for some conditions, but the preexisting neurologic status is a major factor in the final outcome. Multicenter data indicate that most of the children who receive transplants remain significantly neurologically impaired. We wanted to determine whether aggressive metabolic management of ammonia levels after early referral/transfer to a metabolism center and early liver transplantation would result in better neurologic outcomes. We report on 5 children with UCDs, ie, 2 male patients with X-linked ornithine transcarbamylase deficiency and 2 male patients with carbamoyl phosphate synthase deficiency, all of whom had neonatal presentations and underwent orthotopic liver transplantation before 1 year of age, and 1 female patient with partial X-linked ornithine transcarbamylase deficiency that was intractable to medical therapy, who underwent transplantation at 35 months of age. Developmental testing with the Griffiths scale was performed on 3 occasions each, 12 months apart, up to 45 months after transplantation. Full-scale indices for 3 children who underwent early transplantation showed average developmental quotients of 67. All 5 children had metabolic cures. There were no deaths (30-month survival rate: 100%). One child is currently listed for repeat transplantation because of bile duct stenosis and cirrhosis. We conclude that early liver transplantation and aggressive metabolic management improve early neurologic outcomes for children with UCDs, but longer follow-up monitoring is needed.

[Acute promyelocytic leukemia after living donor partial orthotopic liver transplantation]

We encountered a 12-year-old girl with acute promyelocytic leukemia (APL) that occurred 21 months after a living donor partial orthotopic liver transplantation from her father for ornithine transcarbamylase deficiency. FK-506 had been administered for prophylaxis against graft-versus-host reaction. The bone marrow specimen revealed a massive infiltration of promyelocytic blasts (M3 by FAB classification) with chromosome 46, XX, t (15; 17) (q22; q12), being the recipient origin. A PML/RAR alpha chimeric gene was detected by RT-PCR. The patient was diagnosed as having APL and successfully induced to complete remission by chemotherapy including daunorubicin (DNR), cytarabine (araC), and all-trans retinoic acid (ATRA). She has been in continuous remission for 12 months after the treatment. Leukemia after liver transplantation is generally taken as a rare complication. However, recent advances in the survival rate of patients who have undergone liver transplantation will lead to an increase of such cases.

Distinctly abnormal brain metabolism in late-onset ornithine transcarbamylase deficiency

OBJECTIVE

To assess alterations in brain metabolites in patients with late-onset ornithine transcarbamylase deficiency (OTCD).

METHODS

Six unrelated, asymptomatic Japanese late-onset OTCD patients were analyzed by proton MRS ((1)HMRS) using a point-resolved spectroscopy technique (repetition and echo times, 5000 and 30 ms). Localized spectra for the centrum semiovale were acquired and absolute metabolite concentrations were calculated using an LCModel.

RESULTS

Compared with age-matched controls, N-acetylaspartate and creatine concentrations were normal in all patients. The glutamine (Gln) plus glutamate concentration was increased in four patients, which progressed in proportion to the clinical stage. myo-inositol (mI) could not be detected in five symptomatic patients. A decreased choline (Cho) concentration was detected in two clinically severe patients. (1)HMRS after liver transplantation in one patient revealed the normalization of all metabolites.

CONCLUSION

These findings suggest progression of neurochemical events in OTCD, i.e., mI depletion and Gln accumulation followed by Cho depletion, which is reverse of that in hepatic encephalopathy, i.e., Cho depletion followed by mI depletion and Gln accumulation.

Successful living-donor liver transplantation from an asymptomatic carrier mother in ornithine transcarbamylase deficiency

A liver transplantation from an asymptomatic mother, who was a carrier of ornithine transcarbamylase deficiency, to her daughter, who had severe manifestation, was successfully performed. One-year monitoring of plasma amino acid and urinary orotate/orotidine levels revealed no abnormality in the urea cycle in either subject.

Liver transplantation in urea cycle disorders

We report here our experience in the long-term management of 28 patients with citrullinaemia, 13 patients with carbamoyl phosphate synthase deficiency and 15 patients with argininosuccinic aciduria. In addition, we report a national French survey of 119 patients with ornithine transcarbamylase (OTC) deficiency enzymatically characterized in our laboratory. We also include in this report four personal patients (two with OTC and two with citrullinaemia) who were liver transplanted, and one OTC patient from the National French survey. Although this retrospective series is not really representative of the modern treatment combining low protein diet and arginine, sodium benzoate and sodium phenylbutyrate, it is obvious that the long-term outcome of all urea cycle disorders remains very guarded. We highlight the severity of the neonatal forms of such disorders, and mostly for OTC-deficient males. According to this evidence, our policy is not to treat such severely affected patients in the neonatal period who die anyway spontaneously within 2 to 3 days. At the present time, we only have three patients with neonatal citrullinaemia, aged 1, 6 and 10 years respectively, who are still doing well. One of them has been successfully liver transplanted at 5 years. Another transplanted patient died in the post-surgical phase. We emphasize the unexpected severity of argininosuccinic aciduria in which there is no one patient doing well. This is a rather surprising finding as this disorder is easy to manage and rarely presents with recurrent attacks of hyperammonaemia when it is treated by arginine supplementation. This consideration would suggest to extend the indication of orthotopic liver transplantation in this disorder. Finally, the most difficult indication is in the late onset symptomatic female OTC group. In this last group, despite a significant residual activity due to heterozygote status, even with a variable lyonisation, only seven girls are still mentally and neurologically normal. Interestingly, three of these seven were liver-transplanted before the constitution of irreversible neurological damage. These three girls and their family declare their well-being, their feeling to be cured and enjoy their normal life.