A need-adapted transition program after pediatric kidney transplantation

A successful transition of renal transplant recipients from pediatric to adult care requires a structured, need-adapted and multidisciplinary approach to preserve renal graft function during this critical period of life. In this article we present our clinical protocol for transition from pediatric to adult care, which we developed on the basis of the International Society of Nephrology (ISN)/International Pediatric Nephrology Association (IPNA) consensus guidelines influenced by our own experience. This transition program was established in our center in July 2017. The entire transition process is structured and accompanied by a transition key worker (social worker). From 12 years of age we train pediatric renal transplant recipients in medical knowledge, self-management skills and networking with self-help groups. The training is adapted to the individual patient‘s intellectual ability, lasts about 10 years and takes place with increasing intensity. Repeatedly we perform standardized informational interviews and check patient’s knowledge of transplant-related topics. Psychosocial and educational issues are evaluated concomitantly. The actual transfer takes place in a pediatric-adult-transition clinic. Relevant medical and psychosocial aspects are discussed and the future treatment regimen is established. The date of transfer is adapted to the individual patient’s need; it varies between 18 and 24 years of age. In periods of increased risk for non-adherence the transfer is postponed to intensify the efforts for training and assistance. After transfer a standardized evaluation of each individual patient takes place focusing on medical and psychosocial issues and on satisfaction with the transition process. Collection of these data is still in progress and will be analyzed systematically at a later stage in order to evaluate the impact of this new transition program on the stability of transplant function. That analysis might serve as a basis for negotiations about refunding with health insurance companies.

Comparison of two different modes of molecular adsorbent recycling systems for liver dialysis

BACKGROUND

In children acute liver failure is a rare but life-threatening condition from which two-thirds do not recover with supportive therapy. Treatment is limited by the availability of liver transplants. Molecular adsorbent recirculating system (MARS) dialysis is a bridge to transplantation that enhances the chances of survival during the waiting period for a transplant, although it cannot improve survival. Open albumin dialysis (OPAL) is a new mode of albumin dialysis developed to further improve dialysis efficiency.

CASE DIAGNOSIS/TREATMENT

We report a paediatric case of acute-on-chronic liver failure and compare the two modes of albumin dialysis, namely, the MARS and OPAL, used to treat this patient's cholestatic pruritus. Removal of total and direct bilirubin, ammonia and bile acids were measured by serial blood tests. There was an increased removal of bile acids with the OPAL mode, whereas the removal of total and direct bilirubin and ammonia was similar in both modes. The patient reported better improvement in pruritus following OPAL compared to dialysis with the MARS.

CONCLUSION

OPAL may offer a better solution than the MARS in the treatment of refractory pruritus in liver failure.

Combined NGS approaches identify mutations in the intraflagellar transport gene IFT140 in skeletal ciliopathies with early progressive kidney Disease

Ciliopathies are genetically heterogeneous disorders characterized by variable expressivity and overlaps between different disease entities. This is exemplified by the short rib-polydactyly syndromes, Jeune, Sensenbrenner, and Mainzer-Saldino chondrodysplasia syndromes. These three syndromes are frequently caused by mutations in intraflagellar transport (IFT) genes affecting the primary cilia, which play a crucial role in skeletal and chondral development. Here, we identified mutations in IFT140, an IFT complex A gene, in five Jeune asphyxiating thoracic dystrophy (JATD) and two Mainzer-Saldino syndrome (MSS) families, by screening a cohort of 66 JATD/MSS patients using whole exome sequencing and targeted resequencing of a customized ciliopathy gene panel. We also found an enrichment of rare IFT140 alleles in JATD compared with nonciliopathy diseases, implying putative modifier effects for certain alleles. IFT140 patients presented with mild chest narrowing, but all had end-stage renal failure under 13 years of age and retinal dystrophy when examined for ocular dysfunction. This is consistent with the severe cystic phenotype of Ift140 conditional knockout mice, and the higher level of Ift140 expression in kidney and retina compared with the skeleton at E15.5 in the mouse. IFT140 is therefore a major cause of cono-renal syndromes (JATD and MSS). The present study strengthens the rationale for IFT140 screening in skeletal ciliopathy spectrum patients that have kidney disease and/or retinal dystrophy.

beta-Arrestin2 mediates nephrin endocytosis and impairs slit diaphragm integrity

beta-Arrestins mediate internalization of plasma membrane receptors. Nephrin, a structural component of the glomerular slit diaphragm, is a single transmembrane spanning receptor and belongs to the family of adhesion molecules. Its mutation causes a hereditary nephrotic syndrome. We report the previously undescribed interaction of beta-arrestin2 with the nephrin C terminus. The phosphorylation status of nephrin Y1193 regulates inversely the binding of beta-arrestin2 and podocin. The Src-family member Yes, known to enhance podocin-nephrin interaction by nephrin phosphorylation, diminishes beta-arrestin2-nephrin interaction. beta-Arrestin2 induces nephrin endocytosis and attenuates nephrin signaling. This finding suggests that nephrin Y1193 serves as a molecular switch that determines the integrity of the slit diaphragm by functional competition between beta-arrestin2 and podocin. This concept offers a molecular pathomechanism of slit diaphragm distortion and opens therapeutic avenues for glomerular diseases.

Novel approaches to analyse glomerular proteins from smallest scale murine and human samples using DIGE saturation labelling

Loss of renal function is often associated with the injury of kidney glomeruli. It is therefore necessary to understand the mechanisms leading to progressive glomerular diseases; this may be addressed using proteomics. Until now, however, analysis of the glomeruli proteome using 2-DE has been technically hampered by low protein yields from scarce samples. To circumvent this problem, we developed a procedure which allows the human and mouse glomeruli proteome to be analysed. In this study, two different approaches were used to isolate mouse and human glomerular protein from kidney cortex. Mouse glomeruli were extracted by embolisation magnetic beads into the glomerular capillaries. Laser capture microdissection (LCM) was utilised to harvest glomeruli from human biopsy material. Human and murine samples were analysed using a fluorescence saturation labelling technique. Using 3 microg mouse glomerular protein a total of 2900 spots were resolved for differential proteome analysis. Moreover, it was also demonstrated for the first time that only ten glomeruli (0.5 microg) picked by LCM from a slide of a human kidney biopsy material were sufficient to visualise 900 spots. This novel strategy paves the way for future experiments aimed at investigating functional proteomics of glomerular diseases in humans and in mice.