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Sphingosine-1-phosphate (S1P) lyase is a vitamin B6-dependent enzyme that degrades sphingosine-1-phosphate in the final step of sphingolipid metabolism. In 2017, a new inherited disorder was described caused by mutations in SGPL1, which encodes sphingosine phosphate lyase (SPL). This condition is referred to as SPL insufficiency syndrome (SPLIS) or alternatively as nephrotic syndrome type 14 (NPHS14). Patients with SPLIS exhibit lymphopenia, nephrosis, adrenal insufficiency, and/or neurological defects. No targeted therapy for SPLIS has been reported. Vitamin B6 supplementation has therapeutic activity in some genetic diseases involving B6-dependent enzymes, a finding ascribed largely to the vitamins chaperone function. We investigated whether B6 supplementation might have activity in SPLIS patients. We retrospectively monitored responses of disease biomarkers in patients supplemented with B6 and measured SPL activity and sphingolipids in B6-treated patient-derived fibroblasts. In two patients, disease biomarkers responded to B6 supplementation. S1P abundance and activity levels increased and sphingolipids decreased in response to B6. One responsive patient is homozygous for an SPL R222Q variant present in almost 30% of SPLIS patients. Molecular modeling suggests the variant distorts the dimer interface which could be overcome by cofactor supplementation. We demonstrate the first potential targeted therapy for SPLIS and suggest that 30% of SPLIS patients might respond to cofactor supplementation.

Objective The present study aimed to assess the long-term safety and tolerability of valsartan in hypertensive children aged 6-17 years, with or without chronic kidney disease (CKD). Methods This was an 18-month, open-label, multicentre, prospective study conducted in 150 patients with history of hypertension with or without CKD. The primary endpoint was long-term safety and tolerability of valsartan and valsartan-based treatments, assessed in terms of adverse events (AEs), serious AEs, laboratory measurements, estimated glomerular filtration rate (eGFR), urinalysis and electrocardiogram. Results Of 150 enrolled patients, 117 (78%) completed the study. At week 78, a clinically and statistically significant reduction in mean sitting systolic and diastolic blood pressures was observed in all patients (- 14.9 mmHg and - 10.6 mmHg, respectively). Within the first 3 months of treatment, mean urine albumin creatinine ratio decreased in CKD population, which was sustained. A higher percentage of CKD patients had at least one AE compared to non-CKD patients (85.3% vs. 73.3%, respectively). The majority of AEs were mild (50.7%) or moderate (18.7%) in severity. As expected, in patients with underlying CKD, increases in serum potassium, creatinine and blood urea nitrogen were more commonly reported compared to non-CKD patients. A > 25% decrease in Schwartz eGFR was observed in 28.4% of CKD patients and 13.5% of non-CKD patients. Conclusions Valsartan was generally well tolerated, with an AE profile consistent with angiotensin receptor blockers in the overall population and in patients with underlying CKD. Long-term efficacy was maintained and a beneficial effect on proteinuria was observed., Author(s): Randall Lou-Meda [sup.1] , Brigitte Stiller [sup.2] , Zenaida L. Antonio [sup.3] , Ewa Zielinska [sup.4] , Hui-Kim Yap [sup.5] , Hee Gyung Kang [sup.6] , Monique Tan [sup.7] [...]

Long-term humoral immunity is mediated by short-lived plasma cells (replenished by memory B cells) and long-lived plasma cells. Their relative contributions are uncertain for immunity to SARS-CoV-2, especially given the widespread use of novel mRNA vaccines. Yet, this has far-reaching implications in terms of the need for regular booster doses in the general population and perhaps even revaccination in patients receiving B cell-depleting therapy. We aimed to characterise anti-SARS-CoV-2 antibody titres in patients receiving Rituximab following previous SARS-CoV-2 vaccination. We recruited 10 fully vaccinated patients (age: 16.9 ± 2.52 years) with childhood-onset nephrotic syndrome, not in relapse, receiving Rituximab for their steroid/calcineurin-inhibitor sparing effect. Antibodies to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins were measured immediately prior to Rituximab and again ~6 months later, using the Roche Elecys® Anti-SARS-CoV-2 (S) assay. All ten patients were positive for anti-S antibodies prior to Rituximab, with six patients (60%) having titres above the upper limit of detection (>12,500 U/mL). Following Rituximab therapy, there was a reduction in anti-S titres (p = 0.043), but all patients remained positive for anti-S antibodies, with five patients (50%) continuing to have titres >12,500 U/mL. Six patients (60%) were positive for anti-N antibodies prior to Rituximab. Following Rituximab therapy, only three of these six patients remained positive for anti-N antibodies (p = 0.036 compared to anti-S seroreversion). Humoral immunity to SARS-CoV-2 is likely to be mediated in part by long-lived plasma cells. [ABSTRACT FROM AUTHOR]

Author(s): Anil Vasudevan [sup.1] , Kishore Phadke [sup.2 ] , Hui-Kim Yap [sup.3] [sup.4] Author Affiliations: (1) 0000 0004 1770 8558, grid.416432.6, Department of Pediatric Nephrology, St. John's Medical College [...]

Neonatal renal vascular thrombosis is rare but has devastating sequelae. The renal vein is more commonly affected than the renal artery. Most neonates with renal vein thrombosis present with at least one of the three cardinal signs, namely, abdominal mass, macroscopic hematuria and thrombocytopenia, while unilateral renal artery thrombosis presents with transient hypertension. Contrast angiography is the gold standard for diagnosis but because of exposure to radiation and contrast agents, Doppler ultrasound scan is widely used instead. Baseline laboratory tests for platelet count, prothrombin time, activated partial thromboplastin time and fibrinogen concentration are essential before therapy is initiated. Maternal blood is tested for lupus anticoagulant and anticardiolipin antibody. Evaluation for prothrombotic disorders is warranted when thrombosis is clinically significant, recurrent or spontaneous. Management should involve a multidisciplinary team that includes neonatologists, radiologists, pediatric hematologists and nephrologists. In addition to supportive therapy, recent guidelines recommend at least prophylactic heparin therapy in the majority of cases to prevent thrombus extension. Thrombolytic therapy is reserved for bilateral thrombosis compromising kidney function. Long-term sequelae, such as kidney atrophy, systemic hypertension and chronic kidney disease, are common, and follow-up by pediatric nephrologists is recommended for monitoring of kidney function, early detection and management of hypertension and chronic kidney disease., Author(s): Lourdes Paula R. Resontoc[sup.1] , Hui-Kim Yap[sup.1] [sup.2] Author Affiliations: (1) Shaw-NKF-NUH Children's Kidney Center, KTP-National University Children's Medical Institute, National University Health System, Singapore, Singapore (2) Department of [...]

In a representative cohort of immunocompromised young people, we observed marked differences in humoral and cellular responses to a standard two-dose mRNA vaccination regime between disease categories. In conclusion, although immunocompromised young people display attenuated humoral and cellular responses to vaccination in general, there are marked differences in vaccine responses between disease subgroups, not completely explained by immunosuppression used. First, given the heterogeneity in vaccine responses, some patient groups who qualify for an additional primary vaccination dose, for example JIA patients, may not benefit significantly, resulting in suboptimal use of vaccines and vaccination capacity. [Extracted from the article]

Background More than 50% of children with chronic kidney disease (CKD) have uncontrolled hypertension, increasing their long-term risk of cardiovascular disease and progression to kidney failure. Children receiving medications or dialysis may also experience acute blood pressure fluctuations accompanied by debilitating symptoms. We aimed to describe the perspectives of children with CKD and their parental caregivers on blood pressure to inform patient-centered care. Methods Secondary thematic analysis was conducted on qualitative data from the Standardized Outcomes in Nephrology—Children and Adolescents initiative, encompassing 16 focus groups, an international Delphi survey and two consensus workshops. We analyzed responses from children with CKD (ages 8–21 years) and caregivers (of children ages 0–21 years) pertaining to blood pressure. Results Overall, 120 patients and 250 caregivers from 22 countries participated. We identified five themes: invisibility and normalization (reassured by apparent normotension, absence of symptoms and expected links with CKD), confused by ambiguity (hypertension indistinguishable from cardiovascular disease, questioning the need for prophylactic intervention, frustrated by inconsistent messages and struggling with technical skills in measurement), enabling monitoring and maintaining health (gaging well-being and preventing vascular complications), debilitating and constraining daily living (provoking anxiety and agitation, helpless and powerless and limiting life activities) and burden of medications (overwhelmed by the quantity of tablets and distress from unexpected side effects). Conclusions For children with CKD and their caregivers, blood pressure was an important heath indicator, but uncertainty around its implications and treatment hampered management. Providing educational resources to track blood pressure and minimizing symptoms and treatment burden may improve outcomes in children with CKD. [ABSTRACT FROM AUTHOR]

Background Initiating continuous renal replacement therapy (CRRT) in infants exposes them to the dual hemodynamic challenges of high circuit extracorporeal volumes and potential membrane reactions, in the case of acrylonitrile AN69 membranes. The use of the new Prismaflex HF20 membrane in hemodynamically unstable low-body-weight infants on inotropic support has not been reported. Treatment We describe the use of the HF20 (Gambro Lundia AB, Lund, Sweden) membrane in four low-body-weight infants (2.3 to 5.4 kg) with multi-organ dysfunction syndrome who were critically ill in the Pediatric Intensive Care Unit (PICU), hemodynamically unstable, and on inotropes. We were able to achieve target volume loss in all infants without compromising their hemodynamic status. Mean arterial pressures were maintained between 39 and 57 mmHg. The relatively low circuit volume of the HF20 set (60 ml) obviated the need for blood prime in the majority; however, when blood prime was required, there was no adverse reaction with the polyarylethersulfone (PAES) membrane. Solute clearance in these small infants was efficient with correction of metabolic acidosis and electrolyte abnormalities. Excellent circuit lifespan (56.3 [+ or -] 32.3 h) was observed. Conclusions CRRT using the HF20 membrane is safe and hemodynamically well tolerated in high-risk, unstable low-body-weight infants with cardiac dysfunction on multiple inotropes. Keywords Continuous renal replacement therapy * HF20 * Infant * Acute kidney injury, Introduction Critically ill, low-body-weight infants weighing less than 10 kg represent the most technically challenging selection of patients for continuous renal replacement therapy (CRRT). In addition to access issues, the [...]

Focal segmental glomerulosclerosis (FSGS) is a cause of proteinuric kidney disease, compromising both native and transplanted kidneys. Treatment is limited because of a complex pathogenesis, including unknown serum factors. Here we report that serum soluble urokinase receptor (suPAR) is elevated in two-thirds of subjects with primary FSGS, but not in people with other glomerular diseases. We further find that a higher concentration of suPAR before transplantation underlies an increased risk for recurrence of FSGS after transplantation. Using three mouse models, we explore the effects of suPAR on kidney function and morphology. We show that circulating suPAR activates podocyte [β.sub.3] integrin in both native and grafted kidneys, causing foot process effacement, proteinuria and FSGS-like glomerulopathy. Our findings suggest that the renal disease only develops when suPAR sufficiently activates podocyte [β.sub.3] integrin. Thus, the disease can be abrogated by lowering serum suPAR concentrations through plasmapheresis, or by interfering with the suPAR-[β.sub.3] integrin interaction through antibodies and small molecules targeting either uPAR or [β.sub.3] integrin. Our study identifies serum suPAR as a circulating factor that may cause FSGS., Focal segmental glomerulosclerosis (FSGS) is a major cause of endstage renal disease (ESRD) (1). It affects both native and transplanted kidneys (2-4), with recurrence after transplant occurring in about 30% [...]

Of note, HNF1A and HNF1B are associated with Fanconi syndrome and kidney cystic diseases in humans.4,5 Gene set enrichment analysis (GSEA) of Hnf4 target genes (Table S3) corroborated the motif enrichment analysis, as it suggested that Hnf4 target genes were upregulated in PG rats (Figure 3E). The PG rat tubules were dilated compared to WT, thus accounting for the discrepant diameters of the tubules between the WT and PG rats. No histological kidney abnormalities were noted in WT and PS rats, while the PG rats had minimal to moderate histological changes (n = 3 for WT and PS rats, n = 6 for PG rats). Dear editor, We identified angiomotin ( I AMOT i ) as a novel candidate gene for X-linked recessive nephropathy associated with glomerular disease, tubulopathy and progressive kidney cystic disease. [Extracted from the article]

Objective We studied the rate of remission of LN in an international cohort of 248 children and adolescents with biopsy-proven LN. Five different definitions from scientific studies and the definitions recommended by the ACR and Kidney Disease: Improving Global Outcomes were used. Methods Anonymized clinical data in patients with biopsy-proven LN class ≥III (International Society of Nephrology/Royal Pathology Society) diagnosed and treated in the last 10 years in 23 international centres from 10 countries were collected. We compared the rate of patients in complete and partial remission applying the different definitions. Results The mean age at diagnosis was 11 years and 4 months, and 177 were females. The number of patients in complete and partial remission varied a great deal between the different definitions. At 24 months, between 50% and 78.8% of the patients were in full remission as defined by the different criteria. The number of patients in partial remission was low, between 2.3% and 25%. No difference in achieved remission was found between boys and girls or between children and adolescents (P  > 0.05). Patients with East Asian ethnicity reached remission more often than other ethnicities (P  = 0.03–0.0008). Patients treated in high-income countries showed a higher percentage of complete remission at 12 and 24 months (P  = 0.002–0.000001). Conclusion The rate of children and adolescents with LN achieving remission varied hugely with the definition used. Our results give important information for long-awaited treatment studies in children and young people. [ABSTRACT FROM AUTHOR]

COVID‐19 has challenged the global healthcare system through rapid proliferation and lack of existing treatment resulting in over 180 million cases and 3.8 million deaths since December 2019. Although pediatric patients only comprise 1%–2% of diagnosed cases, their incidence of acute kidney injury ranges from 8.2% to 18.2% compared to 49% in adults. Severe infection, initiated by dysregulated host response, can lead to multiorgan failure. In this review, we focus on the use of various blood filters approved for use in pediatric kidney replacement therapy to mitigate adverse effects of severe illness. Therapeutic effects of these blood filters range from cytokine removal (CytoSorb, HA330, HCO/MCO), endotoxin removal (Toraymyxin, CPFA), both cytokine and endotoxin removal (oXiris), and nonspecific removal of proteins (PMMA) that have already been established and can be used to mitigate the various effects of the cytokine storm syndrome in COVID‐19. [ABSTRACT FROM AUTHOR]