Current treatment for primary hyperoxaluria type 1: When should liver/kidney transplantation be considered

Transplantation outcomes in patients with primary hyperoxaluria: a systematic review

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is characterized by hepatic overproduction of oxalate and often results in kidney failure. Liver-kidney transplantation is recommended, either combined (CLKT) or sequentially performed (SLKT). The merits of SLKT and the place of an isolated kidney transplant (KT) in selected patients are unsettled. We systematically reviewed the literature focusing on patient and graft survival rates in relation to the chosen transplant strategy.

METHODS

We searched MEDLINE and Embase using a broad search string, consisting of the terms 'transplantation' and 'hyperoxaluria'. Studies reporting on at least four transplanted patients were selected for quality assessment and data extraction.

RESULTS

We found 51 observational studies from 1975 to 2020, covering 756 CLKT, 405 KT and 89 SLKT, and 51 pre-emptive liver transplantations (PLT). Meta-analysis was impossible due to reported survival probabilities with varying follow-up. Two individual high-quality studies showed an evident kidney graft survival advantage for CLKT versus KT (87% vs. 14% at 15 years, p<0.05) with adjusted HR for graft failure of 0.14 (95% confidence interval: 0.05-0.41), while patient survival was similar. Three other high-quality studies reported 5-year kidney graft survival rates of 48-89% for CLKT and 14-45% for KT. PLT and SLKT yielded 1-year patient and graft survival rates up to 100% in small cohorts.

CONCLUSIONS

Our study suggests that CLKT leads to superior kidney graft survival compared to KT. However, evidence for merits of SLKT or for KT in pyridoxine-responsive patients was scarce, which warrants further studies, ideally using data from a large international registry.

Primary hyperoxaluria complicated with liver cirrhosis: A case report

Primary hyperoxaluria (PH) is a rare, autosomal recessive disorder characterized by overproduction of oxalate caused by a deficiency in a hepatic enzyme. The excess oxalate combines with calcium in the kidneys to form deposits of calcium oxalate, which can lead to nephrocalcinosis and renal failure. PH type 1 (PH1), the most common form of this disease, is caused by a deficiency of the liver-specific enzyme alanine/glyoxylate aminotransferase (AGT). Liver transplantation is performed as a definitive therapy for PH to correct the enzyme defect. Usually, liver depositions are limited and liver function is normal without fibrosis. Here, we report an adult case of liver cirrhosis caused by PH1. A 28-year-old woman was admitted to our hospital under suspicion of PH1 and the presence of nephrocalcinosis. The patient had suffered from kidney stone recurrences from 17 years of age, and was initiated on hemodialysis due to renal failure at the age of 27 years. The serum level of oxalic acid was high, whereas the AGT level in the liver tissue was decreased. Thus, the patient was definitively diagnosed with PH1. Although she had normal liver function, surface nodularity and splenomegaly were detected by computed tomography, suggesting liver cirrhosis. The native liver showed micronodular cirrhosis and portal fibrosis. Several arterioles were filled with rhomboid and polyhedral refractile oxalate crystals and various portal tracts showed these crystals. Our case suggests that long-term oxalosis can lead to liver cirrhosis; thus, PH should be considered one of the causes of liver cirrhosis.

Adult with primary hyperoxaluria type 1 regrets not receiving preemptive liver transplantation during childhood: report of a case

A 32-year-old male was suspected to have primary hyperoxaluria type 1 (PH1) and eventually underwent liver transplantation (LT). He was diagnosed with nephrolithiasis at 9 years of age. Right heminephrectomy was performed for a staghorn calculus. He underwent urethrotomy for urinary retention at 12 years of age. Percutaneous nephrolithotomy was performed for nephrolithiasis when he was 16 years of age. He underwent frequent extracorporeal shock wave lithotripsy for recurrent nephrolithiasis from 18 to 24 years of age. PH1 was suspected at 32 years of age, and pharmacological therapy was also initiated. He developed renal failure at 36 years of age, which was treated with intensive hemodialysis. A definitive diagnosis of PH1 was made based on a liver needle biopsy 1 month later. He received a living-donor LT at 38 years of age, and a living-donor kidney transplant from the same donor 8 months later. Though he made a good recovery, an early diagnosis and preemptive LT are important for PH1 patients.

Liver transplantation for primary hyperoxaluria type 1: a single-center experience during two decades in Japan

BACKGROUND

Primary hyperoxaluria type-1 (PH1) is an autosomal recessive disorder caused by impaired activity of hepatic peroxisomal alanine-glyoxylate aminotransferase that leads to end-stage renal disease (ESRD). A definitive diagnosis is often delayed until ESRD appears. Based on the etiology, liver transplantation (LT) seems to be the definitive treatment.

PATIENTS AND METHODS

Three PH1 patients underwent LT at our institution during two decades.

RESULTS

Two of the patients had family histories of cryptogenic ESRD. All three showed disease onset in childhood, but the definitive diagnosis was delayed in two cases (17 and 37 years of age). These delayed cases resulted in ESRD, and hemodialysis (HD) had been introduced before LT. One patient received domino LT, and the other two underwent living-donor LT (LDLT). One patient finally died of sepsis, and was unable to receive a kidney transplantation (KT) after the domino LT. One patient did not show ESRD, and did not have to undergo KT after LDLT, although extracorporeal shock wave lithotripsy was required for residual ureterolithiasis (8 years after LDLT). The third patient had an uneventful course after LDLT and received living-donor KT from the same donor 8 months after LDLT. Subsequently, HD was successfully withdrawn.

CONCLUSIONS

Establishment of a definitive diagnosis of PH1 is essential. If a methodology for early diagnosis and an intensive care strategy for neonates and infants during the waiting time become well-established, a timely and preemptive LT alone can provide a good chance of cure for PH1 patients.

Transplantation outcomes in primary hyperoxaluria

Optimal transplantation strategies are uncertain in primary hyperoxaluria (PH) due to potential for recurrent oxalosis. Outcomes of different transplantation approaches were compared using life-table methods to determine kidney graft survival among 203 patients in the International Primary Hyperoxaluria Registry. From 1976-2009, 84 kidney alone (K) and combined kidney and liver (K + L) transplants were performed in 58 patients. Among 58 first kidney transplants (32 K, 26 K + L), 1-, 3- and 5-year kidney graft survival was 82%, 68% and 49%. Renal graft loss occurred in 26 first transplants due to oxalosis in ten, chronic allograft nephropathy in six, rejection in five and other causes in five. Delay in PH diagnosis until after transplant favored early graft loss (p = 0.07). K + L had better kidney graft outcomes than K with death-censored graft survival 95% versus 56% at 3 years (p = 0.011). Among 29 year 2000-09 first transplants (24 K + L), 84% were functioning at 3 years compared to 55% of earlier transplants (p = 0.05). At 6.8 years after transplantation, 46 of 58 patients are living (43 with functioning grafts). Outcomes of transplantation in PH have improved over time, with recent K + L transplantation highly successful. Recurrent oxalosis accounted for a minority of kidney graft losses.

Liver transplantation for inherited metabolic disorders of the liver

PURPOSE OF REVIEW

Liver transplantation is curative, life saving or both for a range of inherited diseases affecting the liver. Indications, timing and outcome of transplantation for these diseases are the focus of this review.

RECENT FINDINGS

Liver transplant represents a mode of gene replacement therapy for several disorders, including Wilson disease, hemochromatosis, tyrosinemia, urea cycle defects and hypercholesterolemia in which the primary defect residing in the liver results in hepatic complications or severe extrahepatic disease. Liver transplant is also an important therapeutic modality in multisystemic genetic disorders with major hepatic disease such as glycogen storage disease types I, III and IV and porphyria. For familial amyloidosis and primary hyperoxaluria, liver replacement eliminates the source of the injurious products that results in extrahepatic disease. Innovations in medical and surgical management of these patients have led to improved outcomes providing an important benchmark for future gene therapy of these disorders.

SUMMARY

Recent developments have refined the indications for liver transplant in the treatment of inherited metabolic diseases. The full potential of liver transplant in these disorders can be harnessed by careful patient selection, optimizing timing and perioperative metabolic management of these patients.