Combined liver-kidney transplantation for primary hyperoxaluria type 1 in young children

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.

Therapeutic RNA interference: A novel approach to the treatment of primary hyperoxaluria

RNA interference (RNAi) is a natural biological pathway that inhibits gene expression by targeted degradation or translational inhibition of cytoplasmic mRNA by the RNA induced silencing complex. RNAi has long been exploited in laboratory research to study the biological consequences of the reduced expression of a gene of interest. More recently RNAi has been demonstrated as a therapeutic avenue for rare metabolic diseases. This review presents an overview of the cellular RNAi machinery as well as therapeutic RNAi design and delivery. As a clinical example we present primary hyperoxaluria, an ultrarare inherited disease of increased hepatic oxalate production which leads to recurrent calcium oxalate kidney stones. In the most common form of the disease (Type 1), end‐stage kidney disease occurs in childhood or young adulthood, often necessitating combined kidney and liver transplantation. In this context we discuss nedosiran (Dicerna Pharmaceuticals, Inc.) and lumasiran (Alnylam Pharmaceuticals), which are both novel RNAi therapies for primary hyperoxaluria that selectively reduce hepatic expression of lactate dehydrogenase and glycolate oxidase respectively, reducing hepatic oxalate production and urinary oxalate levels. Finally, we consider future optimizations advances in RNAi therapies.

Cardiac and Liver Disease in Children: Implications for Management Before and After Liver Transplantation

There is close interaction between the functions of the liver and heart affecting the presentation, diagnosis, and outcome of acute and chronic cardiac and liver disease. Conditions affecting both organ systems should be considered when proposing transplantation because the interaction between cardiac disease and liver disease has implications for diagnosis, management, selection for transplantation, and, ultimately, for longterm outcomes after liver transplantation (LT). The combination of cardiac and liver disease is well recognized in adults but is less appreciated in pediatric patients. The focus of this review is to describe conditions affecting both the liver and heart and how they affect selection and management of LT in the pediatric population.

Bilateral native nephrectomy to reduce oxalate stores in children at the time of combined liver-kidney transplantation for primary hyperoxaluria type 1

OBJECTIVE

Primary hyperoxaluria type-1 (PH-1) is a rare genetic disorder in which normal hepatic metabolism of glyoxylate is disrupted resulting in diffuse oxalate deposition and end-stage renal disease (ESRD). While most centers agree that combined liver-kidney transplant (CLKT) is the appropriate treatment for PH-1, perioperative strategies for minimizing recurrent oxalate-related injury to the transplanted kidney remain unclear. We present our management of children with PH-1 and ESRD on hemodialysis (HD) who underwent CLKT at our institution from 2005 to 2015.

METHODS

On chart review, three patients (2 girls, 1 boy) met study criteria. Two patients received deceased-donor split-liver grafts, while one patient received a whole liver graft. All patients underwent bilateral native nephrectomy at transplant to minimize the total body oxalate load. Median preoperative serum oxalate was 72 μmol/L (range 17.8-100). All patients received HD postoperatively until predialysis serum oxalate levels fell <20 μmol/L. All patients, at a median of 7.5 years of follow-up (range 6.5-8.9), demonstrated stable liver and kidney function.

CONCLUSIONS

While CLKT remains the definitive treatment for PH-1, bilateral native nephrectomy at the time of transplant reduces postoperative oxalate stores and may mitigate damage to the renal allograft.

Calcified Double J Stent after Sequential Liver and Renal Transplantation Associated to Primary Oxalosis: Case Report

Hyperoxaluria type I (HPI) is a metabolic disorder secondary to liver alanine glyoxylate aminotransferase deficiency. Renal failure occurs due to the excessive production and precipitation of oxalate in the kidney. Combined liver-renal transplantation is the correct treatment for this condition when end-stage renal failure occurs since in renal transplantation alone the risk of recurrence of the same pathology in the transplanted kidney would be high.

We determined the calcification surrounding the double J stent inserted to the transplant ureter in a short time in a 22-year-old patient who underwent sequential liver and renal transplantation with the diagnoses of oxalosis. In the literature we have not found papers on calcification of double J stent following combined or sequential transplantation. Although after the sequential transplantation the calcification, nephrocalcinosis, and renal stones were practically not of great concern, these patients should be followed up more carefully in terms of stent calcification during the early post-transplant period.

High affinity anti-BSEP antibodies after liver transplantation for PFIC-2 - Successful treatment with immunoadsorption and B-cell depletion

PFIC due to BSEP mutations (PFIC type 2) often necessitates OLT. It has recently been recognized that some PFIC-2 patients develop phenotypic disease recurrence post-OLT due to the appearance of anti-BSEP antibodies. Here, we describe a boy who became cholestatic four yr after OLT during modification of immunosuppression. Canalicular antibody deposits were detected in biopsies of the transplant and antibodies specifically reacting with BSEP were identified at high titers in his serum. These antibodies bound extracellular epitopes of BSEP and inhibited BS transport and were assumed to cause disease recurrence. Consequently, anti-BSEP antibody depletion was pursued by IA and B-cell depletion by anti-CD20 antibodies (rituximab) along with a switch of immunosuppression. This treatment resulted in prolonged relief of symptoms. Depletion of pathogenic anti-BSEP antibodies causing AIBD after OLT in PFIC-2 patients should be considered as a central therapeutic goal.

The primary hyperoxalurias: A practical approach to diagnosis and treatment

Although the primary hyperoxalurias (PH) are rare disorders, they are of considerable clinical importance in relation to calcium oxalate urolithiasis and as a cause of renal failure worldwide. Three distinct disorders have been described at the molecular level. The investigation of any child or adult presenting with urinary tract stones or nephrocalcinosis, must exclude PH as an underlying cause. This paper provides a practical approach to the investigation and diagnosis of PH, indicating the importance of distinguishing between the PH types for the purposes of targeting appropriate therapy. Conservative management is explored and the various transplant options are discussed.

Anesthesia Management of a Deceased Cadaveric-Donor Combined Liver and Kidney Transplant for Primary Hyperoxaluria Type 1: Report of a Case

Primary hyperoxaluria type 1 is an autosomal recessive disorder that is responsible for the overproduction of oxalate and has an incidence of 1 in 120 000 live births. Indications for combined liver and kidney transplant are still debated. However, combined liver and kidney transplant is preferred in various conditions, including primary hyperoxaluria, liver-based metabolic abnormalities affecting the kidney, and structural diseases affecting both the liver and the kidney, such as congenital hepatic fibrosis and polycystic kidney disease. When compared with sequential liver and kidney transplant, the rejection rate of both liver and kidney allografts was reported to be lower than with combined liver and kidney transplant. With proper anesthesia management, the probable increased complications with combined liver and kidney transplant can be prevented. In this report, we present the anesthesia care of a 22-year-old patient with primary hyperoxaluria type 1 who had deceased-donor combined liver and kidney transplant.

Combined liver and kidney transplantation in children: analysis of renal graft outcome

BACKGROUND

Combined liver-kidney transplantation (CLKT) is the accepted treatment for patients with both liver failure and progressive renal insufficiency. Long-term outcome data for CLKT in children is sparse and controversy exists as to whether simultaneous CLKT with organs from the same donor confers immunologic and survival benefit to the kidney allograft. We report the long-term renal graft outcomes of 40 patients who had simultaneous CLKT.

METHODS

A retrospective analysis of kidney graft survival (time from transplantation to death, return to dialysis or last follow-up event) in all pediatric patients (age < 18 years old) who underwent CLKT from March 1994 to January 2015. A 1:1 ratio of controls (deceased donor kidney recipients from our centre matched for age (±2 years) at transplant, time from transplant (±1 year) and treated with the same immunosuppressive regime) to cases was used to compare outcome. Estimated glomerular filtration rate (e-GFR) was calculated using the Schwartz formula. Survival curves were determined using Kaplan-Meier analysis.

RESULTS

The kidney graft survival for CLKT patients was 87.4, 82, and 82 % at 1, 5, and 10 years; kidney graft survival for isolated KT patients were 97.2, 93, and 93 % at 1, 5, and 10 years (p = NS). There were two acute rejection episodes (5 %) in the CLKT group compared to five (12.5 %) episodes in the isolated KT group. There was no statistically significant difference in e-GFR at 1, 5, and 10 years in the two groups but there was a statistically significantly greater decline in e-GFR in the KT group compared to CLKT group from 5-10 years following transplant.

CONCLUSIONS

There are fewer acute rejection episodes following CLKT compared to isolated KT, and we noted a higher mean e-GFR at 1, 5, and 10 years with significantly lesser decline in e-GFR from 5 to 10 years in the CLKT group.

Anaesthesia and intensive care for simultaneous liver-kidney transplantation: A single-centre experience with 12 recipients

Background and Aims:

The perioperative management of patients presenting for simultaneous liver and kidney transplantation (SLKT) is a complex process. We analysed SLKTs performed in our institution to identify preoperative, intraoperative and post-operative challenges encountered in the management.

Methods:

We retrospectively studied the case records of 12 patients who underwent SLKT between 2009 and 2014 and analysed details of pre-operative evaluation and optimisation, intraoperative anaesthetic management and the implications of use of perioperative continuous renal replacement therapy (CRRT) and the post-operative course of these patients.

Results:

Of the total 12 cases, 4 were under 16 years of age. The indications for SLKT were primary hyperoxaluria (5), congenital hepatic fibrosis with polycystic kidney disease (2), ethanol-related end-stage liver disease (ESLD) with hepatorenal syndrome type 1 (1). Four patients had ESLD with end-stage renal disease due to other causes. Six recipients received live donor grafts and 6 patients received cadaveric grafts. Seven patients received intraoperative CRRT. Mean duration of surgery was 12.5 h. Cardiac output monitors used were trans-oesophageal echocardiogram (2), pulmonary artery catheter (1) and pulse contour cardiac output monitor (3). There was 1 sepsis-related mortality on 7^th post-operative day.

Conclusion:

A thorough pre-operative evaluation and optimisation, knowledge and anticipation of potential problems, and meticulous intraoperative fluid management guided by appropriate monitoring and use of CRRT when needed can help in achieving successful outcomes.

An institutional experience of pre-emptive liver transplantation for pediatric primary hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH1) is an inherited metabolic disease that culminates in ESRF. Pre-emptive liver transplantation (pLTx) treats the metabolic defect and avoids the need for kidney transplantation (KTx). An institutional experience of pediatric PH1 LTx is reported and compared to the literature. Between 2004 and 2015, eight children underwent pLTx for PH1. Three underwent pLTx with a median GFR of 40 (30-46) mL/min/1.73 m(2) and five underwent sequential combined liver-kidney transplantation (cLKTx); all were on RRT at the time of cLKTx. In one case of pLTx, KTx was required eight and a half yr later. pLTx was performed in older (median 8 vs. 2 yr) and larger children (median 27 vs. 7.75 kg) that had a milder PH1 phenotype. In pediatric PH1, pLTx, ideally, should be performed before renal and extrarenal systemic oxalosis complications have occurred, and pLTx can be used "early" or "late." Early is when renal function is preserved with the aim to avoid renal replacement. However, in late (GFR < 30 mL/min/1.73 m(2) ), the aim is to stabilize renal function and delay the need for KTx. Ultimately, transplant strategy depends on PH1 phenotype, disease stage, child size, and organ availability.

Pediatric combined liver-kidney transplantation: a 2015 update

PURPOSE OF REVIEW

The experience of combined liver-kidney transplantation (CLKT) is limited in pediatric populations. This strategy is, however, required in specific diseases such as metabolic diseases (namely primary hyperoxaluria type one and methylmalonic acidemia), autosomal recessive polycystic kidney disease, miscellaneous ciliopathies and atypical hemolytic uremic syndrome.

RECENT FINDINGS

Different series and registry studies have confirmed the feasibility of pediatric CLKT with encouraging results in the long term, even in the youngest and smallest patients, provided that highly trained multidisciplinary teams are involved in this global management. As such, the long-term outcomes after CLKT are currently comparable to that of isolated liver or kidney transplantations, even though the immediate postoperative period remains challenging.

SUMMARY

Some questions remain nevertheless unanswered, such as the respective place of combined versus sequential liver-kidney transplantation, especially in primary hyperoxaluria and autosomal recessive polycystic kidney disease. The aim of this review was therefore to provide a 2015 update on pediatric CLKT. In the future, international collaborative studies and registries may help to improve our knowledge of this rare and still highly challenging technique.

Review of combined liver and kidney transplantation in children

In this review, we focused on CLKT with regard to indication, results, outcome, and future developments. PH1 is one of the most common diagnoses for adult and pediatric patients qualifying for CLKT. The other major indication for combined transplantation is ARPKD. CLKT appears to be superior to sequential liver and kidney transplantation in the majority of patients and overall results following CLKT are now good, even in small children. Clinical observations suggest that there is an immunological advantage of CLKT in comparison with isolated liver or kidney transplantation. More clinical studies are necessary to identify the best candidates for CLKT while the availability of donor organs is low.

Transplantation in autosomal recessive polycystic kidney disease: liver and/or kidney?

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by enlarged kidneys with dilated collecting ducts and congenital hepatic fibrosis. There is a variable rate of progression of kidney and liver disease. Portal hypertension and Caroli's disease occur from liver involvement that contributes to morbidity and mortality. Approximately 40 % of patients have a severe disease phenotype leading to rapid onset of end-stage kidney disease (ESKD) and signs of portal hypertension and the rest may have predominant involvement of either the kidney or liver. It is important for the physician to establish the extent of organ involvement before deciding on the ultimate plan of management, especially when transplantation is required. Isolated renal transplantation can be considered when liver involvement is minimal. If hepatobiliary disease is prominent, and kidney function is preserved, management options are based on individual characteristics. In the presence of significant liver disease and ESKD, consideration should be given to combined liver kidney transplantation, which can be beneficial in eliminating the consequences of both kidney and liver disease. However, this is a complex surgical procedure that needs to be performed at experienced transplant centers. Improvement in surgical techniques has considerably improved short-term graft survival with the added advantage of the liver offering immunologic protection to the kidney allograft.

Primary disease recurrence—effects on paediatric renal transplantation outcomes

Primary disease recurrence after renal transplantation is mainly diagnosed by examination of biopsy samples, but can also be associated with clinical symptoms. In some patients, recurrence can lead to graft loss (7-8% of all graft losses). Primary disease recurrence is generally associated with a high risk of graft loss in patients with focal segmental glomerulosclerosis, membranous proliferative glomerulonephritis, primary hyperoxaluria or atypical haemolytic uraemic syndrome. By contrast, disease recurrence is associated with a limited risk of graft loss in patients with IgA nephropathy, renal involvement associated with Henoch-Schönlein purpura, antineutrophil cytoplasmic antibody-associated glomerulonephritis or lupus nephritis. The presence of systemic diseases that affect the kidneys, such as sickle cell anaemia and diabetes mellitus, also increases the risk of delayed graft loss. This Review provides an overview of the epidemiology, pathophysiology and management of primary disease recurrence in paediatric renal graft recipients, and describes the overall effect on graft survival of each of the primary diseases listed above. With appropriate management, few paediatric patients should be excluded from renal transplantation programmes because of an increased risk of recurrence.

Outcomes of combined liver-kidney transplantation in children: analysis of the scientific registry of transplant recipients

Combined liver-kidney transplantation (CLKT) in children is uncommon and outcomes have not been well defined. Using the Scientific Registry of Transplant Recipients, data were analyzed on 152 primary pediatric CLKTs performed from October 1987 to February 2011, to determine their outcome in the largest series reported to date. Patient survival was 86.8%, 82.1% and 78.9% at 1, 5 and 10 years, liver graft survival was 81.9%, 76.5% and 72.6%, and kidney graft survival was 83.4%, 76.5% and 66.8%. By way of comparison, the Registry was queried for pediatric patient survival following isolated liver transplantation (LT) during the same time frame: 86.7%, 81.2% and 77.4% and following isolated kidney transplant (KT): 98.2%, 95.4% and 90% at 1, 5 and 10 years. In patients having undergone CLKT, primary hyperoxaluria was associated with reduced patient (p = 0.01), liver graft (p = 0.01) and kidney graft survival (p = 0.01). Furthermore, graft outcome following CLKT improved over the past decade (p = 0.04 for liver, p = 0.02 for kidney), but this did not translate into improved patient outcome (p = 0.2). All in all, our results confirmed that survival following LT was less than following KT, and that CLKT offered similar patient survival to isolated LT.

Therapeutic hepatocyte transplant for inherited metabolic disorders: functional considerations, recent outcomes and future prospects

The applications, outcomes and future strategies of hepatocyte transplantation (HTx) as a corrective intervention for inherited metabolic disease (IMD) are described. An overview of HTx in IMDs, as well as preclinical evaluations in rodent and other mammalian models, is summarized. Current treatments for IMDs are highlighted, along with short- and long-term outcomes and the potential for HTx to supplement or supplant these treatments. Finally, the advantages and disadvantages of HTx are presented, highlighted by long-term challenges with interorgan engraftment and expansion of transplanted cells, in addition to the future prospects of stem cell transplants. At present, the utility of HTx is represented by the potential to bridge patients with life-threatening liver disease to organ transplantation, especially as an adjuvant intervention where severe organ shortages continue to pose challenges.

Living donor liver transplantation for pediatric patients with metabolic disorders: the Japanese multicenter registry

LDLT is indicated for a variety of metabolic disorders, primarily in Asian countries due to the absolute scarcity of deceased donor LT. We analyzed data for all pediatric LDLTs performed between November 1989 and December 2010, during which 2224 pediatric patients underwent LDLT in Japan. Of these patients, 194 (8.7%) underwent LDLT for metabolic disorders. Wilson's disease (n = 59; 30.4%) was the most common indication in the patients with metabolic disorders, followed by OTCD (n = 40; 20.6%), MMA (n = 20; 10.3%), and GSD (n = 15; 7.7%). The one-, five-, 10-, and 15-yr patient and graft survival rates were 91.2%, 87.9%, 87.0%, and 79.3%, and 91.2%, 87.9%, 86.1%, and 74.4%, respectively. Wilson's disease and urea cycle deficiency were associated with better patient survival. The use of heterozygous donors demonstrated no negative impact on either the donors or recipients. With regard to X-linked OTCD, symptomatic heterozygote maternal donors should not be considered potential donor candidates. Improving the understanding of the long-term suitability of this treatment modality will require the registration and ongoing evaluation of all patients with inherited metabolic disease considered for LT.

Primary hyperoxaluria Type 1: indications for screening and guidance for diagnosis and treatment

Primary hyperoxaluria Type 1 is a rare autosomal recessive inborn error of glyoxylate metabolism, caused by a deficiency of the liver-specific enzyme alanine:glyoxylate aminotransferase. The disorder results in overproduction and excessive urinary excretion of oxalate, causing recurrent urolithiasis and nephrocalcinosis. As glomerular filtration rate declines due to progressive renal involvement, oxalate accumulates leading to systemic oxalosis. The diagnosis is based on clinical and sonographic findings, urine oxalate assessment, enzymology and/or DNA analysis. Early initiation of conservative treatment (high fluid intake, pyridoxine, inhibitors of calcium oxalate crystallization) aims at maintaining renal function. In chronic kidney disease Stages 4 and 5, the best outcomes to date were achieved with combined liver-kidney transplantation.

Primary hyperoxalurias: disorders of glyoxylate detoxification

Glyoxylate detoxification is an important function of human peroxisomes. Glyoxylate is a highly reactive molecule, generated in the intermediary metabolism of glycine, hydroxyproline and glycolate mainly. Glyoxylate accumulation in the cytosol is readily transformed by lactate dehydrogenase into oxalate, a dicarboxylic acid that cannot be metabolized by mammals and forms tissue-damaging calcium oxalate crystals. Alanine-glyoxylate aminotransferase, a peroxisomal enzyme in humans, converts glyoxylate into glycine, playing a central role in glyoxylate detoxification. Cytosolic and mitochondrial glyoxylate reductase also contributes to limit oxalate production from glyoxylate. Mitochondrial hydroxyoxoglutarate aldolase is an important enzyme of hydroxyproline metabolism. Genetic defect of any of these enzymes of glyoxylate metabolism results in primary hyperoxalurias, severe human diseases in which toxic levels of oxalate are produced by the liver, resulting in progressive renal damage. Significant advances in the pathophysiology of primary hyperoxalurias have led to better diagnosis and treatment of these patients, but current treatment relies mainly on organ transplantation. It is reasonable to expect that recent advances in the understanding of the molecular mechanisms of disease will result into better targeted therapeutic options in the future.

Hyperoxaluria and rapid development of renal failure following a combined liver and kidney transplantation: emphasis on sequential transplantation

Primary hyperoxaluria type I (PH I) is a rare genetic disorder that leads to end stage renal disease (ESRD) at an early age due to excessive deposition of calcium oxalate in the kidney. Combined liver-kidney transplantation (LKTx) has been advocated as the treatment of choice for patients with PH I who have progressive renal disease. With combined LKTx the risk of early renal failure secondary to oxalate deposition is anticipated. Here we report a patient with PH I who developed ESRD and underwent a combined LKTx. He lost the kidney graft secondary to early recurrence of oxalosis. Repeat kidney transplantation 13 months after the initial procedure was successful. Elevated plasma oxalate levels persisted for a long time following LKTx and lead to further deposition of oxalate in the second kidney graft. Combined LKTx for patients with PH I requires meticulous preparation and very careful post operative management. Sequential liver transplantation followed by kidney transplantation is to be considered for PH I patients who have ESRD and very high oxalate load.

Primary hyperoxaluria

Primary hyperoxalurias (PH) are inborn errors in the metabolism of glyoxylate and oxalate. PH type 1, the most common form, is an autosomal recessive disorder caused by a deficiency of the liver-specific enzyme alanine, glyoxylate aminotransferase (AGT) resulting in overproduction and excessive urinary excretion of oxalate. Recurrent urolithiasis and nephrocalcinosis are the hallmarks of the disease. As glomerular filtration rate decreases due to progressive renal damage, oxalate accumulates leading to systemic oxalosis. Diagnosis is often delayed and is based on clinical and sonographic findings, urinary oxalate assessment, DNA analysis, and, if necessary, direct AGT activity measurement in liver biopsy tissue. Early initiation of conservative treatment, including high fluid intake, inhibitors of calcium oxalate crystallization, and pyridoxine in responsive cases, can help to maintain renal function in compliant subjects. In end-stage renal disease patients, the best outcomes have been achieved with combined liver-kidney transplantation which corrects the enzyme defect.

Combined split liver and kidney transplantation in a three-year-old child with primary hyperoxaluria type 1 and complete thrombosis of the inferior vena cava

PH1 is an inborn error of the metabolism in which a functional deficiency of the liver-specific peroxisomal enzyme, AGT, causes hyperoxaluria and hyperglycolic aciduria. Infantile PH1 is the most aggressive form of this disease, leading to early nephrocalcinosis, systemic oxalosis, and end-stage renal failure. Infantile PH1 is rapidly fatal in children unless timely liver-kidney transplantation is performed to correct both the hepatic enzyme defect and the renal end-organ damage. The surgical procedure can be further complicated in infants and young children, who are at higher risk for vascular anomalies, such as IVC thrombosis. Although recently a limited number of children with IVC thrombosis have underwent successful kidney transplantation, successful multi-organ transplantation in a child with complete IVC thrombosis is quite rare. We report here the interesting and technically difficult case of a three-yr-old girl with a complete thrombosis of the IVC, who was the recipient of combined split liver and kidney transplantation for infantile PH1. Although initial delayed renal graft function with mild-to-moderate acute rejection was observed, the patient rapidly regained renal function after steroid boluses, and was soon hemodialysis-independent, with good diuresis. Serum and plasma oxalate levels progressively decreased; although, to date they are still above normal. Hepatic and renal function indices were at, or approaching, normal values when the patient was discharged 15-wk post-transplant, and the patient continues to do well, with close and frequent follow-up. This is the first report of a successful double-organ transplant in a pediatric patient presenting with infantile PH1 complicated by complete IVC thrombosis.

Excellent renal function and reversal of nephrocalcinosis 8 years after isolated liver transplantation in an infant with primary hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH-1) is a rare autosomal recessive disease caused by the absence or deficiency of the liver-specific intermediary metabolic enzyme alanine glyoxylate aminotransferase. The prognosis of this metabolic disease is poor. Theoretically, the primary metabolic defect can be cured by liver transplantation. However, controversy exists around the age and stage of the disease that liver transplantation should be performed. We report on a patient who presented at the early age of 2 months with nephrocalcinosis. Isolated liver transplantation was performed at the age of 21 months. Eight years later, the estimated glomerular filtration rate was 85 ml/min/1.73 m(2), and imaging studies did not reveal nephrocalcinosis. This case report supports the strategy of early isolated liver transplantation in patients with PH-1.

Pre-emptive liver transplantation for primary hyperoxaluria (PH-I) arrests long-term renal function deterioration

BACKGROUND

Primary hyperoxaluria-I (PH-I) is a serious metabolic disease resulting in end-stage renal disease. Pre-emptive liver transplantation (PLT) for PH-I is an option for children with early diagnosis. There is still little information on its effect on long-term renal function in this situation.

METHODS

Long-term assessment of renal function was conducted using Schwartz's formula (estimated glomerular filtration rate-eGFR) in four children (Group A) undergoing PLT between 2002 and 2008, and a comparison was done with eight gender- and sex-matched controls (Group B) having liver transplantation for other indications.

RESULTS

All patients received a liver graft from a deceased donor. Median follow-up for the two groups was 64 and 94 months, respectively. One child in Group A underwent re-transplantation due to hepatic artery thrombosis, while acute rejection was seen in one. A significant difference was seen in eGFR at transplant (81 vs 148 mL/min/1.73 m(2)) with greater functional impairment seen in the study population. In Group A, renal function reduced by 21 and 11% compared with 37 and 35% in Group B at 12 and 24 months, respectively. At 2 years post-transplantation, there was no significant difference in eGFR between the two groups (72 vs 100 mL/min/1.73 m(2), respectively; P = 0.06).

CONCLUSIONS

Renal function remains relatively stable following pre-emptive LTx for PH-I. With early diagnosis of PH-I, isolated liver transplantation may prevent progression to end-stage renal disease and the need for renal transplantation.

A single center experience of combined liver kidney transplantation

With advancements in the operative techniques, patient survival following liver transplantation (LTx) has increased substantially. This has led to the acceleration of pre-existing kidney disease because of immunosuppressive nephrotoxicity making additional kidney transplantation (KTx) inevitable. On the other hand, in a growing number of patients on the waiting list to receive liver, long waiting time has resulted in adverse effect of decompensated liver on the kidney function. During the last two decades, the transplant community has considered combined liver kidney transplantation (CLKTx) to overcome this problem. The aim of our study is to present an overview of our experience as well as a review of the literature in CLKTx and to discuss the controversy in this regard. All performed CLKTx (n = 22) at our institution as well as all available reported case series focusing on CLKTx are extracted. The references of the manuscripts were cross-checked to implement further articles into the review. The analyzed parameters include demographic data, indication for LTx and KTx, duration on the waiting list, Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, immunosuppressive regimen, post-transplant complications, graft and patient survival, and cause of death. From 1988 to 2009, a total of 22 CLKTx were performed at our institution. The median age of the patients at the time of CLKTx was 44.8 (range: 4.5-58.3 yr). The indications for LTx were liver cirrhosis, hyperoxaluria type 1, polycystic liver disease, primary or secondary sclerosing cholangitis, malignant hepatic epithelioid hemangioendothelioma, cystinosis, and congenital biliary fibrosis. The KTx indications were end-stage renal disease of various causes, hyperoxaluria type 1, polycystic kidney disease, and cystinosis. The mean follow-up duration for CLKTx patients were 4.6 +/- 3.5 yr (range: 0.5-12 yr). Overall, the most important encountered complications were sepsis (n = 8), liver failure leading to retransplantation (n = 4), liver rejection (n = 3), and kidney rejection (n = 1). The overall patient survival rate was 80%. Review of the literature showed that from 1984 to 2008, 3536 CLKTx cases were reported. The main indications for CLKTx were oxalosis of both organs, liver cirrhosis and chronic renal failure, polycystic liver and kidney disease, and liver cirrhosis along with hepatorenal syndrome (HRS). The most common encountered complications following CLKTx were infection, bleeding, biliary complications, retransplantation of the liver, acute hepatic artery thrombosis, and retransplantation of the kidney. From the available data regarding the need for post-operative dialysis (n = 673), a total of 175 recipients (26%) required hemodialysis. During the follow-up period, 154 episodes of liver rejection (4.3%) and 113 episodes of kidney rejection (3.2%) occurred. The cumulative 1, 2, 3, and 5 yr survival of both organs were 78.2%, 74.4%, 62.4%, and 60.9%, respectively. Additionally, the cumulative 1, 2, 3, and 5 yr patient survival were 84.9%, 52.8%, 45.4%, and 42.6%, respectively. The total number of reported deaths was 181 of 2808 cases (6.4%), from them the cause of death in 99 (55%) cases was sepsis. It can be concluded that there is still no definitive evidence of better graft and patient survival in CLKTx recipients when compared with LTx alone because of the complexity of the exact definition of irreversible kidney function in LTx candidates. Additionally, CLKTx is better to be performed earlier than isolated LTx and KTx leading to the avoidance of deterioration of clinical status, high rate of graft loss, and mortality. Shorter graft ischemia time and more effective immunosuppressive regimens can reduce the incidence of graft malfunctioning in CLKTx patients. Providing a model to reliably determine the need for CLKTx seems necessary. Such a model can be shaped based upon new and precise markers of renal function, and modification of MELD system.

Indications for combined liver and kidney transplantation in children

A significant number of patients awaiting liver transplantation have associated renal failure and renal dysfunction is associated with increased morbidity and mortality after LT. There has been a recent increase in the number of CLKT in adults. The common indications for CLKT in children are different from those of adults and include metabolic diseases affecting the kidney with or without liver dysfunction and congenital developmental abnormalities affecting both organs. The results are generally encouraging among these groups of patients. Early evaluation and listing of patients before they become severely ill or have major systemic manifestations of their metabolic problem are important.

Transplantation procedures in children with primary hyperoxaluria type 1: outcome and longitudinal growth

BACKGROUND

Cure of the metabolic defect in primary hyperoxaluria type 1 (PH1) is possible with liver transplantation (LTx). Preemptive LTx (PLTx) was promoted to prevent chronic kidney disease due to nephrocalcinosis and urolithiasis. However, timing of this procedure is difficult in view of the heterogeneity of PH1 and effective conservative treatment. Combined liver-kidney transplantation (LKTx) is able to cure metabolic defect and replace renal function at the same time and is effective and indicated for patients with or approaching end-stage renal disease (ESRD). Sometimes a sequential approach for LKTx (first liver, then kidney) has been recommended.

METHODS

We report on 13 patients with PH1 since 1995 who underwent transplantation procedures in our center for PH1 at a median age of 4.7 (range 1.4-8.9) years.

RESULTS

The first two patients, planned for a sequential strategy, died early after LTx because of infectious complications. Four patients underwent PLTx at a median glomerular filtration rate of 65 (range 27-98) mL/min/1.73 m/day (Hoppe et al., Pediatr Nephrol 1996; 10: 488), and three patients still have sufficient residual renal function after a follow-up of median 11.6 years. Seven patients with ESRD received a combined LKTx, including four with infantile oxalosis, and three weighing less than 10 kg. There was no mortality and catch-up growth was observed in most patients.

CONCLUSION

In summary and conclusion, transplantation procedures are challenging in PH1, but our results including growth data are encouraging. PLTx remains an option despite the difficulties in timing the procedure. LKTx is indicated for patients with ESRD and is possible even in patients with infantile oxalosis and may improve longitudinal growth.

Combined liver-kidney transplantation in children: indications and outcome

Although it remains a relatively infrequent procedure in children, CLKT has become a viable option for a select group of pediatric patients with severe liver and kidney disease. Most are performed for rare primary diseases such as PH1, but a selected few are performed in the setting of concomitant hepatic and renal failure of uncertain etiology and prognosis. This article reviews the indications for and outcomes following CLKT in children. While it focuses on the specific primary diseases which impact liver and kidney function simultaneously, it addresses the indications based on concomitant hepatic and renal failure, such as seen in the hepatorenal syndrome, as well.

[Inherited monogenic kidney stone diseases: recent diagnostic and therapeutic advances]

Hereditary monogenic kidney stone diseases are rare diseases, since they account for nearly 2% of nephrolithiasis cases in adults and 10% in children. Most of them are severe, because they frequently are associated with nephrocalcinosis and lead to progressive impairment of renal function unless an early and appropriate etiologic treatment is instituted. Unfortunately, treatment is often lacking or started too late since they are often misdiagnosed or overlooked. The present review reports the genotypic and phenotypic characteristics of monogenic nephrolithiases, with special emphasis on the recent advances in the field of diagnosis and therapeutics. Monogenic stone diseases will be classified into three groups according to their mechanism: (1) inborn errors of the metabolism of oxalate (primary hyperoxalurias), uric acid (hereditary hyperuricemias) or other purines (2,8-dihydroxyadeninuria), which, in addition to stone formation, result in crystal deposition in the renal parenchyma; (2) congenital tubulopathies affecting the convoluted proximal tubule (such as Dent's disease, Lowe syndrome or hypophosphatemic rickets), the thick ascending limb of Henlé's loop (such as familial hypomagnesemia and Bartter's syndromes) or the distal past of the nephron (congenital distal tubular acidosis with or without hearing loss), which are frequently associated with nephrocalcinosis, phosphatic stones and extensive tubulointerstitial fibrosis; (3) cystinuria, an isolated defect in tubular reabsorption of cystine and dibasic aminoacids, which results only in the formation of stones but requires a cumbersome treatment. Analysis of stones appears of crucial value for the early diagnosis of these diseases, as in several of them the morphology and composition of stones is specific. In other cases, especially if nephrocalcinosis, phosphatic stones or proteinuria are present, the evaluation of blood and urine chemistry, especially with regard to calcium, phosphate and magnesium, is the key of diagnosis. Search for mutations is now increasingly performed in as much as genetic counselling is important for the detection of heterozygotes in autosomic recessive diseases and of carrier women in X-linked diseases. In conclusion, better awareness to the rare monogenic forms of nephrolithiasis and/or nephrocalcinosis should allow early diagnosis and treatment which are needed to prevent or substantially delay progression of end-stage renal disease. Analysis of every first stone both in children and in adults should never be neglected, in order to early detect unusual forms of nephrolithiasis requiring laboratory evaluation and deep etiologic treatment.

Hyperoxaluria and systemic oxalosis: current therapy and future directions

Excessive urinary oxalate excretion, termed hyperoxaluria, may arise from inherited or acquired diseases. The most severe forms are caused by increased endogenous production of oxalate related to one of several inborn errors of metabolism, termed primary hyperoxaluria. Recurrent kidney stones and progressive medullary nephrocalcinosis lead to the loss of kidney function, requiring dialysis or transplantation, accompanied by systemic oxalate deposition that is termed systemic oxalosis. For most primary hyperoxalurias, accurate diagnosis leads to the use of therapies that include pyridoxine supplementation, urinary crystallisation inhibitors, hydration with enteral fluids and, in the near future, probiotic supplementation or other innovative therapies. These therapies have varying degrees of success, and none represent a cure. Organ transplantation results in reduced patient and organ survival when compared with national statistics. Exciting new approaches under investigation include the restoration of defective enzymatic activity through the use of chemical chaperones and hepatocyte cell transplantation, or recombinant gene therapy for enzyme replacement. Such approaches give hope for a future therapeutic cure for primary hyperoxaluria that includes correction of the underlying genetic defect without exposure to the life-long dangers associated with organ transplantation.

Primary hyperoxaluria type 1: still challenging!

Primary hyperoxaluria type 1, the most common form of primary hyperoxaluria, is an autosomal recessive disorder caused by a deficiency of the liver-specific enzyme alanine: glyoxylate aminotransferase (AGT). This results in increased synthesis and subsequent urinary excretion of the metabolic end product oxalate and the deposition of insoluble calcium oxalate in the kidney and urinary tract. As glomerular filtration rate (GFR) decreases due to progressive renal involvement, oxalate accumulates and results in systemic oxalosis. Diagnosis is still often delayed. It may be established on the basis of clinical and sonographic findings, urinary oxalate +/- glycolate assessment, DNA analysis and, sometimes, direct AGT activity measurement in liver biopsy tissue. The initiation of conservative measures, based on hydration, citrate and/or phosphate, and pyridoxine, in responsive cases at an early stage to minimize oxalate crystal formation will help to maintain renal function in compliant subjects. Patients with established urolithiasis may benefit from extracorporeal shock-wave lithotripsy and/or JJ stent insertion. Correction of the enzyme defect by liver transplantation should be planned, before systemic oxalosis develops, to optimize outcomes and may be either sequential (biochemical benefit) or simultaneous (immunological benefit) liver-kidney transplantation, depending on facilities and access to cadaveric or living donors. Aggressive dialysis therapies are required to avoid progressive oxalate deposition in established end-stage renal disease (ESRD), and minimization of the time on dialysis will improve both the patient's quality of life and survival.

The role of preemptive liver transplantation in primary hyperoxaluria type 1

In primary hyperoxaluria the deficiency or mistargeting of hepatic alanine-glyoxylate aminotransferase (AGT) leads to the overproduction of oxalate resulting in hyperoxaluria and renal damage due to urolithiasis and/or nephrocalcinosis. Presently, the cure of the metabolic defect can be achieved only by liver transplantation. While for patients with end-stage renal disease combined hepatorenal transplantation is recommended, the concept of preemptive liver transplantation (PLTX), i.e. cure of the metabolic defect before renal damage occurs, has received considerable attention. Due to the heterogenous clinical course in PH1, optimal timing of PLTX is a matter of debate. Advocators of PLTX would consider a patient with a slowly declining GFR, reaching levels of 40-60 ml/min/1.73 m(2), as an ideal candidate, while others would continue medical treatment in these patients and opt for rapid combined liver-kidney transplantation if GFR reaches even lower levels. This review will discuss the background and rationale of PLTX and gives an update on 11 patients with PLTX who have been reported in the literature to date.

Cadaveric orthotopic auxiliary split liver transplantation and kidney transplantation: an alternative for type 1 primary hyperoxaluria

Liver transplantation (LTX) corrects the enzymatic defect responsible for type 1 primary hyperoxaluria (PH1). It has been advocated in combination with kidney transplantation (KTX) in patients with renal failure from PH1 because KTX alone can result in early graft loss. A 58-year-old male patient with PH1 on hemodialysis underwent resection of the left lateral segment of the liver followed by orthotopic auxiliary left lateral segment liver transplantation and kidney transplantation from a deceased donor. The serum oxalate dropped from 34.8 micromol/L before transplant to 3.6-8.3 in the first months posttransplant to <1 micromol/L (normal range 0.4-3.0). One year after posttransplant, the patient has an iothalamate glomerular filtration rate of 58 ml/min. Orthotopic auxiliary LTX is an alternative to whole LTX in PH1. By using a split deceased donor liver, it does not deprive the donor pool and protects the recipient from liver failure in case of graft loss.

A 20-year experience of combined liver/kidney transplantation for primary hyperoxaluria (PH1): the European PH1 transplant registry experience 1984-2004

Primary hyperoxaluria (PH1) is a condition caused by a hepatic-based enzyme defect which can lead to renal failure due to oxalate stone disease, obstructive uropathy and nephrocalcinosis. It has been shown that the underlying metabolic defect can be corrected by liver transplantation and in most cases (renal failure having already occurred) is accompanied by a kidney graft. This paper describes the current results of 127 liver transplants performed in 117 patients over a 20-year period from 1984 to 2004 in 35 European centres. The mean age at onset of symptoms was 5.6 +/- 7.8 years and the mean age at which a diagnosis was made was 8.8 +/- 9.5 years. The diagnosis was confirmed by liver biopsy proven decreased AGT activity in 68% of cases, hyperoxaluria in 74%, hyperglycolicaciduria in 37% and hyperoxalaemia in 50%. Patients were transplanted at a mean age of 16.5 +/- 11.4 years following a period of dialysis of 3.2 +/- 3.2 years (range 0-14.4 years). 1-, 5- and 10-year patient survival values were 86, 80 and 69%, respectively, and liver graft survival rates of 80, 72 and 60% at the same time intervals. There have been 27 deaths and 10 liver retransplants have been carried out. Patient outcomes are improved when prolonged periods on dialysis and the complications of systemic oxalosis have not occurred.

Calcium oxalate deposition in renal allografts: morphologic spectrum and clinical implications

Many aspects of calcium oxalate (CaOx) deposition in renal transplant biopsies are not known. Review of all renal transplant biopsies performed in a 7-year period showed that CaOx deposition could be classified into three groups. Group I: Seven biopsies within a month post-transplant displayed rare CaOx foci against a background of acute tubular necrosis or acute cell-mediated rejection. At follow-up, five grafts functioned well and two failed due to chronic allograft nephropathy. CaOx in this context was an incidental finding secondary to a sudden excretion of an end-stage renal disease-induced increased body burden of CaOx. Group II: Two biopsies performed 2 and 10 months post-transplant showed rare CaOx foci against a background of chronic allograft nephropathy, leading to graft loss. CaOx in this context reflected nonspecific parenchymal deposition due to chronic renal failure regardless of causes. Group III: One biopsy with recurrent PH1 characterized by marked CaOx deposition associated with severe tubulointerstitial injury and graft loss 6 months post-transplant. There were two previously reported cases in which CaOx deposition in the renal allografts was due the antihypertensive drug naftidrofuryl oxalate or increased intestinal absorption of CaOx. CaOx deposition in renal allografts can be classified in different categories with distinctive morphologic features and clinical implications.

Recurrence of primary disease in children after renal transplantation: an evidence-based update

The availability of new and more effective anti-rejection therapy has succeeded in reducing the incidence of acute cellular rejection in first months post-renal transplant. This in turn has escalated the order of significance of recurrence of primary disease in the renal allograft as a cause for patient morbidity and graft loss during this period. The aim of this review is to survey current literature, identify issues and potential areas for future research related to recurrence of primary disease after renal transplant. Our review of published reports suggests that our current knowledge and practice, related to the management of recurrence of primary disease, are mainly based on non-randomized and uncontrolled case series. The future need for well designed mechanistic as well as therapeutic, controlled and randomized multicenter clinical trials cannot be overemphasized.

Primary hyperoxaluria: simultaneous combined liver and kidney transplantation from a living related donor

Primary hyperoxaluria type 1 (PH1) is a rare inherited metabolic disorder in which deficiency of the liver enzyme AGT leads to renal failure and systemic oxalosis. Timely, combined cadaveric liver-kidney transplantation (LKT) is recommended for end-stage renal failure (ESRF) caused by PH1; however, the shortage of cadaveric organs has generated enthusiasm for living-related transplantation in years. Recently, successful sequential LKT from the same living donor has been reported in a child with PH1. We present a sister-to-brother simultaneous LKT in a pediatric patient who suffered from PH1 with ESRF. Twelve months after transplantation, his daily urine oxalate excretion was decreased from 160 mg to 19.5 mg with normal liver and renal allograft functions. In addition to the well-known advantages of living organ transplantation, simultaneous LKT may facilitate early postoperative hemodynamic stability and may induce immunotolerance and allow for low-dose immunosuppression.

Combined liver-kidney and kidney-alone transplantation in primary hyperoxaluria

Combined liver-kidney and kidney-only transplantation outcomes in primary hyperoxaluria (PH) are described. Strategies for the selection of type and timing of transplantation and pretransplantation and posttransplantation management are reviewed. Records were reviewed for 16 patients with PH who received 9 liver-kidney and 10 kidney-only transplants. Plasma oxalate values declined from 61 +/- 42 micromol/L pretransplantation to 9 +/- 6 micromol/L 1 month after transplantation in liver-kidney transplant recipients and 92 +/- 19 to 9 +/- 5 micromol/L in kidney-only transplant recipients. In most liver-kidney transplant recipients, hyperoxaluria persisted for 6 to 18 months after transplantation. Follow-up was 3.5 +/- 4.1 years in liver-kidney and 4.5 +/- 6.3 years in kidney-alone transplant recipients. Patient survival rates were 78% for liver-kidney and 89% for kidney-only transplant recipients. No hepatic allografts were lost. Three of 9 liver-kidney and 6 of 10 kidney-alone transplants lost renal allograft function. In those with functioning kidneys, renal clearance was 45.1 +/- 19.5 mL/min/1.73 m(2) in liver-kidney transplant recipients and 49.5 +/- 26.1 mL/min/1.73 m(2) in kidney-only transplant recipients at last follow-up. Kaplan-Meier 1-, 2-, 3-, and 5-year renal allograft survival rates for patients undergoing transplantation after 1984 were 78%, 78%, 52%, and 52% in liver-kidney transplant recipients and 86%, 71%, 54%, and 36% in kidney-only transplant recipients. Simultaneous grafting of liver and kidney after the development of renal insufficiency is recommended for the majority of patients with PH type I (PH-I). Kidney-alone transplantation is recommended for those with pyridoxine-responsive type I disease because pharmacological therapy allows favorable management of oxalate production in this situation. Kidney-alone transplantation also is recommended for PH type II (PH-II). This disease is less severe than PH-I, and it is currently unknown whether liver transplantation will correct the metabolic defect responsible for PH-II.