Jun Oh

University Medical Center Hamburg - Eppendorf · Department of Pediatric Nephrology Pediatric Hepatology and Transplantation

Introduction: Feeding and swallowing development after birth involves a complex interplay of anatomical, neurological, and social processes [1]. While there is a wealth of research on assessing swallowing and feeding disorders in children [2, 3], the physiological development of swallowing has received limited attention or focuses on single factor...

Background Pediatric organ transplantation is the primary treatment for end‐organ failure. Improving medication adherence and healthcare compliance can decrease healthcare burdens, graft rejection, morbidity, and mortality. Adolescents commonly struggle with non‐adherence, necessitating a smooth transition to adult care. This systematic review aims...

Background In kidney transplant recipients (KTR), BK polyomavirus-associated nephropathy (BKPyVAN) is a major cause of graft loss. To facilitate the clearance of BKPyV-DNAemia, reduction of immunosuppression is currently the treatment of choice but may increase the risk of graft rejection. Methods This international CERTAIN study was designed to d...

This study by the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) was designed to determine the incidence, risk factors, current management strategies, and outcomes of antibody-mediated rejection (ABMR) in pediatric kidney transplant recipients (pKTR). We performed an international, multicenter, longitudinal cohort study of da...

Bardet-Biedl syndrome (BBS) is a rare multisystemic disorder caused by variants of currently 26 different genes. Depending on the severity of the different symptoms, the diagnosis is often delayed. Patients are cared for by (pediatric) endocrinologists and nephrologists as well as ophthalmologists. One of the most common symptoms is obesity, which...

Introduction Data on age-related differences in rejection rates, infectious episodes, and tacrolimus exposure in pediatric kidney transplant recipients (pKTRs) on a tacrolimus-based immunosuppressive regimen are scarce. Methods We performed a large-scale analysis of 802 pKTRs from the Cooperative European Paediatric Renal Transplant Initiative (CE...

Methylmalonic acidemias (MMAs) are rare inherited metabolic diseases with multiorgan involvement. Chronic kidney disease (CKD) is a common complication, leading to kidney failure, dialysis, and kidney transplantation (KT). The objective of these guidelines was to develop clinical practice recommendations focusing on specific aspects of the kidney m...

Context The pathophysiology of cystinosis-associated metabolic bone disease is complex. Objective We hypothesized a disturbed interaction between osteoblasts and osteoclasts. Design Binational cross-sectional multicenter study. Setting Hospital clinics. Patients One hundred and three patients with cystinosis (61% children) with chronic kidney d...

Introduction: Clostridioides difficile infection (CDI), as a nosocomial disease, is associated with high morbidity and mortality. Even though the incidence of CDI has been declining in Germany in recent years, the individual infection may pose a medical challenge despite therapeutic advances. The aim here is to clarify which gaps practitioners con...

Introduction Primary hyperoxaluria type 1 (PH1) is known for its variable clinical course, even within families. However, the extent of this heterogeneity has not been well-studied. We aimed to analyze intrafamilial clinical heterogeneity and disease course among siblings in a large cohort of familial PH1 cases. Methods A retrospective registry st...

Background Infantile nephropathic cystinosis (INC) is a rare lysosomal storage disorder, mostly and often firstly affecting the kidneys, together with impaired disharmonious growth and rickets, eventually resulting in progressive chronic kidney disease (CKD). With the introduction of cysteamine therapy, most pediatric patients reach adulthood with...

Allograft loss after pediatric kidney transplantation (KTx) is highest in adolescents and young adults. Non-adherence and Health Care Transition (HCT) are important factors, but others do also contribute. Patients were randomized 1:1. The intervention group (IG) included a central case manager, a communication app, and joined transition rounds for...

Background Data on age-related differences in rejection rates, infectious episodes and tacrolimus exposure in pediatric kidney transplant recipients (pKTR) on a uniform tacrolimus-based immunosuppressive regimen are scarce. Methods We therefore performed a large-scale analysis of 802 pKTR from the CERTAIN registry from 40 centers in 14 countries....

Background: Minimal change disease and primary focal segmental glomerulosclerosis in adults, along with idiopathic nephrotic syndrome in children, are immune-mediated podocytopathies that lead to nephrotic syndrome. Autoantibodies targeting nephrin have been found in patients with minimal change disease, but their clinical and pathophysiological r...

Background and Aims Cystinosis-associated metabolic bone disease (CMBD) is a major challenge in the treatment of patients with infantile nephropathic cystinosis (NC). Study data are limited due to small case numbers, lack of adults or patients on renal replacement therapy and/or inadequate assessment of bone health. Method We investigated markers...

Background: Kidney transplantation (KT) is the optimal treatment for end-stage kidney disease, with graft survival critically affected by the recipient's immune response. The role of the gut microbiome in modulating this immune response remains underexplored. Our study investigates how microbiome alterations might associate with allograft rejection...

Background: Kidney transplantation (KTx) from small donors is associated with inferior graft survival in registry studies, whereas single-center studies show favorable results. Methods: We compared 175 pediatric KTx from small donors ≤20 kg (SDKTx) with 170 age-matched recipients from adult donors (ADKTx) from 20 centers within the Cooperative E...

Introduction We investigated the relationship between metabolic acidosis over time and allograft outcome in pediatric kidney transplantation (KTx). Methods This registry study collected data up to 10 years posttransplant. Survival analysis for a composite end point of graft loss or estimated glomerular filtration rate (eGFR) ≤ 30 ml/min per 1.73 m...

Cystinosis is a rare autosomal-recessive lysosomal storage disease that progressively affects multiple organs beginning with the kidneys. Patients require lifelong multidisciplinary care for the management of kidney disease and progressive extra-renal manifestations, and thus, they are especially fragile and vulnerable during transition from pediat...

Zusammenfassung Das Bardet-Biedl-Syndrom (BBS) ist eine seltene, autosomal-rezessiv vererbte Multisystemerkrankung. Pathophysiologisch liegt eine Funktionsstörung des Primärziliums vor. Die Klinik ist heterogen und variabel und zeigt sich insbesondere in einer Retinadystrophie, Adipositas, Polydaktylie, Nierenauffälligkeiten, Hypogonadismus und Ent...

Background This study by the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) was designed to determine the incidence, risk factors, current management strategies and outcomes of antibody-mediated rejection (ABMR) in pediatric kidney transplant recipients (pKTR). Methods We performed an international, multicenter, longitudinal...

Background Tacrolimus, a calcineurin inhibitor (CNI), is currently the first-line immunosuppressive agent in kidney transplantation. The therapeutic index of tacrolimus is narrow due to due to the substantial impact of minor variations in drug concentration or exposure on clinical outcomes (i.e., nephrotoxicity), and it has a highly variable intra-...

Despite significant medical and technical improvements in the field of dialysis, the morbidity and mortality among patients with chronic kidney disease (CKD) stage 5 on dialysis remains extremely high. Hemodiafiltration (HDF), a dialysis method that combines the two main principles of hemodialysis (HD) and hemofiltration—diffusion and convection—ha...

Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS) is associated with high morbidity and relevant mortality. Previous small studies showed that volume expansion could improve the course and outcome of STEC-HUS. The aim of this single-center study was to evaluate the effect of volume expansion on the clinical course and outcome in ST...

Introduction Unlike idiopathic nephrotic syndrome (NS), hereditary podocytopathies are not expected to recur after kidney transplantation. However, some reports of posttransplant recurrence of NS in patients carrying variants in the NPHS2 gene have been described, notably with the p.Arg138Gln variant, which is more prevalent in Europe. The objectiv...

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapie...

The transplantation model provides the opportunity to assess the relevance of a molecule of interest for tumor cell extravasation by using a respective genetically modified donor animal. Here, we present a protocol for orthotopic single-lung transplantation in mice as a tool for lung metastasis studies. We describe steps for animal preparation, lun...

Background Early onset de novo focal segmental glomerular sclerosis (FSGS) in the kidney allograft in patients without FSGS in the native kidney is a rare disorder in children. It usually occurs mostly beyond the first year after kidney transplantation and often leads to graft loss. Standardized treatment protocols have not yet been established. C...

Guanidino compounds such as dimethylarginines (SDMA, ADMA) and L-homoarginine ((L-)hArg) can interfere with bioavailability and function of the main NO-donor L-arginine (L-Arg). High ADMA and SDMA but low L-hArg concentrations have been associated with cardio- and cerebrovascular events and mortality in adults. The role of guanidino compounds in pa...

Crigler–Najjar Syndrome (CNS) with residual activity of UDP-glucuronosyltransferase 1A1 (UGT1A1) and no need for daily phototherapy is called mild Crigler–Najjar Syndrome. Most of these patients need medical treatment for enzyme induction (phenobarbital) to lower blood levels of unconjugated bilirubin (UCB). Apart from this, no long-term problems h...

The situation of limited data concerning the response to COVID-19 mRNA vaccinations in immunocom-promised children hinders evidence-based recommendations. This prospective observational study investigated humoral and T cell responses after primary BNT162b2 vaccination in secondary immunocompromised and healthy children aged 5–11 years. Participants...

Background: Infantile nephropathic cystinosis (INC) is a systemic lysosomal storage disease causing intracellular cystine accumulation, resulting in renal Fanconi syndrome, progressive kidney disease (CKD), rickets, malnutrition, and myopathy. An INC-specific disproportionately diminished trunk length compared to leg length poses questions regardi...

Ziel: Die Nahrungsaufnahme und das Schlucken erfordern zahlreiche anatomische, neurologische und soziale Entwicklungsprozesse (Delaney & Arvedson, 2008). Während bereits eine Vielzahl an Studien zur Bewertung von Schluck- und Fütterstörungen bei Säuglingen und Kindern existieren (Dodrill & Gosa, 2015; Moroco & Aaronson, 2022), ist die physiologisch...

Background and Aims In primary hyperoxaluria type 1 (PH 1) a rare enzymatic defect in the liver leads to a hepatic overproduction of oxalate. The resulting hyperoxaluria can cause nephrocalcinosis, urolithiasis and renal failure. Conservative treatment options such as hyperhydration, citrate and pyridoxine aim to slow the progression of the disease...

Purposes Despite reports of a declining incidence over the last decade, Clostridioides difficile infection (CDI) is still considered the most important healthcare-associated causes of diarrhea worldwide. In Germany, several measures have been taken to observe, report, and influence this development. This report aims to analyze the development of ho...

Podocytes are differentiated epithelial cells which play an essential role to ensure a normal function of the glomerular filtration barrier (GFB). In addition to their adhesive properties in maintaining the integrity of the filtration barrier, they have other functions, such as synthesis of components of the glomerular basement membrane (GBM), prod...

[This corrects the article DOI: 10.3389/fimmu.2023.1092335.].

Introduction: Combined or sequential liver and kidney transplantation (CLKT/SLKT) restores kidney function and corrects the underlying metabolic defect in children with end-stage kidney disease in primary hyperoxaluria type 1 (PH1). However, data on long-term outcome, especially in children with infantile PH1, are rare. Methods: All pediatric PH...

Introduction Rejection remains the main cause of allograft failure in paediatric kidney transplantation and is driven by donor-recipient HLA mismatching. Modern computational algorithms enable assessment of HLA mismatch immunogenicity at the molecular level (molecular-mismatch, molMM). Whilst molMM has been shown to correlate with alloimmune outcom...

Background: The coronavirus SARS-CoV-2 disease (COVID-19) pandemic affected lifestyles and resulted in significant weight gain in the general population. Its impact on children after kidney transplantation (KTx) is unknown. Methods: We retrospectively evaluated body mass index (BMI) z-scores during the COVID-19 pandemic in 132 pediatric KTx pati...

The diagnosis of glomerular disease still mostly relies on the conventional histologic and immunohistochemical analysis of biopsies, thereby failing to provide a molecular disease understanding and stratification as the fundamental basis for an individualized therapy. It is out of the question that nephrology will be transformed into a field of sys...

Background: The unphysiological composition of peritoneal dialysis (PD) fluids induces progressive peritoneal fibrosis, hypervascularization and vasculopathy. Information on these alterations after kidney transplantation (KTx) is scant. Methods: Parietal peritoneal tissues were obtained from 81 pediatric patients with chronic kidney disease stag...

Objectives: Protocol liver biopsies (PLB) are part of the follow-up program at many pediatric liver transplant centers, but the impact on clinical decision-making and allograft histology following adjustments of immunosuppression (IS) after PLB has not been thoroughly analyzed. Methods: Following our previous single-center cohort study, we have...

Background Data on comorbidities in children on kidney replacement therapy (KRT) is scarce. Considering their high relevance for prognosis and treatment, this study aims to analyse the prevalence and implications of comorbidities in European children on KRT. Methods We included data from patients aged < 20 years when commencing KRT from 2007 to 20...

Background Randomized controlled trials in pediatric kidney transplantation are hampered by low incidence and prevalence of kidney failure in children. Real-World Data from patient registries could facilitate the conduct of clinical trials by substituting a control cohort. However, the emulation of a control cohort by registry data in pediatric kid...

Pediatric patients on kidney replacement therapy (KRT) are among the most vulnerable during large-scale disasters, either natural or man-made. Hemodialysis (HD) treatments may be impossible because of structural damage and/or shortage of medical supplies, clean water, electricity, and healthcare professionals. Lack of peritoneal dialysis (PD) solut...

Introduction Little is known about the consequences of deranged chronic kidney disease–mineral and bone disorder (CKD-MBD) parameters on kidney allograft function in children. We examined a relationship between these parameters over time and allograft outcome. Methods This registry study from the Cooperative European Paediatric Renal Transplant In...

Almost 2 years into the pandemic and with vaccination of children significantly lagging behind adults, long-term pediatric humoral immune responses to SARS-CoV-2 are understudied. The C19.CHILD Hamburg (COVID-19 Child Health Investigation of Latent Disease) Study is a prospective cohort study designed to identify and follow up children and their ho...

Background Pulse wave velocity (PWV) is a measure of arterial stiffness. We investigated PWV and blood pressure (BP) to determine to what extent BP changes contribute to arterial stiffness, and secondly, to identify influencing factors on BP in children after kidney transplantation. Methods Seventy children ≥ 2.5 years post-transplantation with at...

Die Prävalenz von Nierensteinen bei Erwachsenen nimmt weltweit weiterhin zu 1. Da Kinder häufig einen anderen Lebensstil und eine andere Ernährung haben, sind Nierensteine in dieser Altersgruppe selten. Jüngste Studien haben aber gezeigt, dass die Inzidenz und Prävalenz von Nierensteinen global bei Kindern zunimmt 2. Die Ursachen für Nephrolithiasi...

Background: Hemolytic uremic syndrome secondary to Shiga-toxin-producing Escherichia coli infection (STEC-HUS) generally shows a favorable outcome. Few cases develop extra-renal complications, since neurological involvement is an important cause of morbidity and mortality. The role of complement in STEC-HUS has been recently highlighted, and the u...

SARS-CoV-2 is still a major burden for global health despite effective vaccines. With the reduction of social distancing measures, infection rates are increasing in children, while data on the pediatric immune response to SARS-CoV-2 infection is still lacking. Although the typical disease course in children has been mild, emerging variants may pres...

Nephropathic cystinosis is a rare lysosomal storage disease whose basic defect, impaired transport of cystine out of lysosomes, results in intracellular cystine storage. Affected individuals exhibit renal Fanconi Syndrome in infancy, end-stage kidney disease at approximately 10 years of age, and many other systemic complications. Oral cysteamine th...

Infantile nephropathic cystinosis, due to impaired transport of cystine out of lysosomes, occurs with an incidence of 1 in 100–200,000 live births. It is characterized by renal Fanconi syndrome in the first year of life and glomerular dysfunction progression to end-stage kidney disease by approximately 10 years of age. Treatment with oral cysteamin...

Background: Preexistent LUTD are considered a hostile environment, which might negatively impact KTx survival. In such cases, surgical reconstruction of the bladder is required. However, there is still disagreement on the optimal timing of the reconstruction procedure. Methods: This is a multicenter analysis of data from the CERTAIN Registry. In...

Background: The supply of viable organ donations falls significantly below the demand. Discrepancies concerning the availability of transplants cannot be explained solely by the various consent models used in different countries. There is evidence that religious beliefs of patients, potential donors, and healthcare professionals also play an impor...

Increasing the information depth of single kidney biopsies can improve diagnostic precision, personalized medicine and accelerate basic kidney research. Until now, information on mRNA abundance and morphologic analysis has been obtained from different samples, missing out on the spatial context and single‐cell correlation of findings. Herein, we pr...

BACKGROUND AND AIMS Tight junctions (TJ) and transcellular ion channels and transporters define solute transport characteristics across cellular barriers, which is of particular interest in patients on peritoneal dialysis (PD). Little is known about their cell specific expression, and regulation in PD. We studied their expression in human endotheli...