Omic Studies on In Vitro Cystinosis Model: siRNA-Mediated CTNS Gene Silencing in HK-2 Cells.

Cystinosis is an autosomal recessive disease caused by mutations in the CTNS gene encoding a protein called cystinosine, which is a lysosomal cystine transporter. Disease-causing mutations lead to accumulation of cystine crystals in the lysosomes, thereby causing dysfunction of vital organs. Determination of the increased leukocyte cystine level is one of the most used methods for diagnosis. However, this method is expensive, difficult to perform, and may yield different results in different laboratories. In this study, a disease model was created with CTNS gene-silenced HK2 cells, which can mimic cystinosis in cell culture, and multiomics methods (ie, proteomics, metabolomics, and fluxomics) were implemented at this cell culture to investigate new biomarkers for the diagnosis. CTNS-silenced cell line exhibited distinct metabolic profiles compared with the control cell line. Pathway analysis highlighted significant alterations in various metabolic pathways, including alanine, aspartate, and glutamate metabolism; glutathione metabolism; aminoacyl-tRNA biosynthesis; arginine and proline metabolism; beta-alanine metabolism; ascorbate and aldarate metabolism; and histidine metabolism upon CTNS silencing. Fluxomics analysis revealed increased cycle rates of Krebs cycle intermediates such as fumarate, malate, and citrate, accompanied by enhanced activation of inorganic phosphate and ATP production. Furthermore, proteomic analysis unveiled differential expression levels of key proteins involved in crucial cellular processes. Notably, peptidyl-prolyl cis-trans isomerase A, translation elongation factor 1-beta (EF-1beta), and 60S acidic ribosomal protein decreased in CTNS-silenced cells. Additionally, levels of P0 and tubulin α-1A chain were reduced, whereas levels of 40S ribosomal protein S8 and Midasin increased. Overall, our study, through the utilization of an in vitro cystinosis model and comprehensive multiomics approach, led to the way toward the identification of potential new biomarkers while offering valuable insights into the pathogenesis of cystinosis.

Calcineurin inhibitor-related hyperkalemia is caused by hyporeninemic hypoaldosteronism and fludrocortisone is an effective treatment: Report of a case series and review of the literature.

INTRODUCTION: Calcineurin inhibitors (CNIs) are widely used in transplantation. Although CNI-related hyperkalemia is common (10%-60.6%), the underlying pathogenetic mechanism is not well-elucidated and may lead to dose adjustment or treatment withdrawal. OBJECTIVE: The aim of this study is to describe CNI-related hyperkalemia due to hyporeninemic hypoaldosteronism in pediatric transplant recipients who were successfully treated with fludrocortisone. METHOD: In a total of 55 hematopoietic stem cell (HSCT) and 35 kidney transplant recipients followed according to institutional immunosuppression protocols, recipients diagnosed with CNI-related hyperkalemia were reviewed. Recipients who were receiving intravenous fluid, potassium, or were diagnosed with hemolysis, acute graft rejection, or had an eGFR < 30 mL/min/1.73m2, were excluded. A detailed analysis of clinical history as well as biochemical studies was carried out to reveal possible pathophysiology. RESULTS: Three pediatric transplant recipients (one HSCT, two kidney transplantation) with findings of hyperkalemia, hyponatremia, and a mild elevation in blood urea nitrogen while on CNIs were recruited. Urinary potassium excretion was diminished while sodium excretion was increased. Plasma aldosterone levels were low, and renin was not increased in response. Primary adrenal insufficiency was ruled out, and hyporeninemic hypoaldosteronism was diagnosed. CNI-related hyperkalemia was detected earlier in case 1, who had HSCT (22 days), than in the second and third cases, who had kidney transplantation (24 and 30 months post-transplantation, respectively). The discrepancy was hypothesized to be explained by higher overall CNI dose due to higher serum target CNI used in HSCT than kidney transplantation. Electrolyte imbalance was reversed upon administration of physiologic dose fludrocortisone (0.05 mg, daily), while fludrocortisone was ceased after CNI withdrawal in case 1, which is additional evidence for the etiological association of CNIs and hyporeninemic hypoaldosteronism. CONCLUSION: Our three cases strengthen the premise that CNI-related hyperkalemia may be due to hyporeninemic hypoaldosteronism, and the timing and severity may be related to CNI dose. Fludrocortisone is a safe and effective treatment in CNI-related hyperkalemia, providing maintenance of CNIs, which are one of the essential therapeutic agents for pediatric transplantation.

Acute kidney injury in children with moderate-severe COVID-19 and multisystem inflammatory syndrome in children: a referral center experience.

BACKGROUND: Data on the characteristics of acute kidney injury (AKI) in pediatric COVID-19 and MIS-C are limited. We aimed to define the frequency, associated factors and early outcome of AKI in moderate, severe or critical COVID-19 and MIS-C; and to present a tertiary referral center experience from Türkiye. METHODS: Hospitalized patients ≤ 18 years of age with confirmed COVID-19 or MIS-C at Ihsan Dogramaci Children's Hospital, Hacettepe University, between March 2020-December 2021 were enrolled. The characteristics of AKI in the COVID-19 group were investigated in moderate, severe and critically ill patients; patients with mild COVID-19 were excluded. RESULTS: The median (Q1-Q3) age in the COVID-19 (n = 66) and MIS-C (n = 111) groups was 10.7 years (3.9-15.2) and 8.7 years (4.5-12.7), respectively. The frequency of AKI was 22.7% (15/66) in COVID-19 and 15.3% (17/111) in MIS-C; all MIS-C patients with AKI and 73.3% (11/15) of COVID-19 patients with AKI had AKI at the time of admission. Multivariate analyses revealed need for vasoactive/inotropic agents [Odds ratio (OR) 19.233, p = 0.002] and presence of vomiting and/or diarrhea (OR 4.465, p = 0.036) as independent risk factors of AKI in COVID-19 patients; and need for vasoactive/inotropic agents (OR 22.542, p = 0.020), procalcitonin and ferritin levels as independent risk factors of AKI in the MIS-C group. Age was correlated with lymphocyte count (r = -0.513, p < 0.001) and troponin level (r = 0.518, p < 0.001) in MIS-C patients. Length of hospital stay was significantly longer in both groups with AKI, compared to those without AKI. Mortality was 9.1% in the COVID-19 group; and was associated with AKI (p = 0.021). There was no mortality in MIS-C patients. AKI recovery at discharge was 63.6% in COVID-19 survivors and 100% in MIS-C patients. CONCLUSIONS: Independent risk factors for AKI were need for vasoactive/inotropic agents and vomiting/diarrhea in moderate, severe or critical COVID-19 patients; and need for vasoactive/inotropic agents and severe inflammation in MIS-C patients. Our findings suggest that inflammation and cardiac dysfunction are associated with AKI in MIS-C patients; and the association with age in this group merits further studies in larger groups. Early outcome is favorable; long-term follow-up for kidney functions is needed.

Variable phenotype and genotype of pediatric patients with HNF1B nephropathy.

AIMS: Hepatocyte nuclear factor 1ß (HNF1B) mutations are the most common monogenic cause of congenital anomalies of the kidney and urinary tract (CAKUT). We aimed to investigate clinical and genetic characteristics of patients with HNF1B nephropathy to expand its phenotypic and genetic spectrum. MATERIALS AND METHODS: This retrospective cohort study included 16 unrelated pediatric patients (6 females, 10 males) from 13 families with genetically confirmed HNF1B-related nephropathy. RESULTS: Abnormal prenatal kidney abnormalities were present in 13 patients (81.3%). The most common antenatal kidney abnormality was kidney cysts, which were observed in 8 patients (61.5%). Urinary system abnormalities (vesicoureteral reflux (VUR) and ureteropelvic junction obstruction (UPJO)) were present in 4 patients (25%). HNF1B analysis uncovered missense variants in 4 families (30.8%) as the most common genetic abnormality. In addition, 4 novel pathological variations have been defined. During follow-up, hypomagnesemia and hyperuricemia were observed in 7 (43.8%) and 5 patients (31.3%), respectively. None of the patients with a missense variant had hypomagnesemia. However, 7 out of 12 patients (58.3%) with a non-missense variant had hypomagnesemia (p = 0.09). None of the patients had an HNF1B score below 8, and the mean score was 15.3 ± 4.4. The mean follow-up period was 7.4 ± 5.0 years. While 100% of patients (n = 4) with missense variants were in various stages of CKD (CKD2: 2 patients, CKD3: 2 patients), 25% of those with non-missense variants had CKD (CKD2, 3, and 5; 1 patient, respectively) (p = 0.026). CONCLUSION: Patients with HNF1B-associated disease have concomitant urinary system abnormalities such as VUR or UPJO. Missense variants seem to be the most common pathological variations in HNF1B gene and have higher risk of CKD.

Adolescence-onset atypical hemolytic uremic syndrome: is it different from infant-onset?

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare, mostly complement-mediated thrombotic microangiopathy. The majority of patients are infants. In contrast to infantile-onset aHUS, the clinical and genetic characteristics of adolescence-onset aHUS have not been sufficiently addressed to date. METHODS: A total of 28 patients (21 girls, 7 boys) who were diagnosed as aHUS between the ages of ≥10 years and <18 years were included in this study. All available data in the Turkish Pediatric aHUS registry were collected and analyzed. RESULTS: The mean age at diagnosis was 12.8±2.3 years. Extra-renal involvement was noted in 13 patients (46.4%); neurological involvement was the most common (32%). A total of 21 patients (75%) required kidney replacement therapy. Five patients (17.8%) received only plasma therapy and 23 (82%) of the patients received eculizumab. Hematologic remission and renal remission were achieved in 25 (89.3%) and 17 (60.7%) of the patients, respectively. Compared with the infantile-onset aHUS patients, adolescent patients had a lower complete remission rate during the first episode (p = 0.002). Genetic analyses were performed in all and a genetic variant was detected in 39.3% of the patients. The mean follow-up duration was 4.9±2.6 years. At the last visit, adolescent patients had lower eGFR levels (p = 0.03) and higher rates of chronic kidney disease stage 5 when compared to infantile-onset aHUS patients (p = 0.04). CONCLUSIONS: Adolescence-onset aHUS is a rare disease but tends to cause more permanent renal dysfunction than infantile-onset aHUS. These results may modify the management approaches in these patients.

COVID-19 in Children with Chronic Kidney Disease; Does it Differ Much?

BACKGROUND: COVID-19 is known to have a mild course in children, however more data on pediatric chronic kidney disease (CKD) is needed. We aimed to assess the incidence and severity of COVID-19 in pediatric CKD patients. METHODS: A questionnaire including demographics, COVID-19 history, symptoms, and vaccination status was applied to patients with CKD. We also retrospectively reviewed the presentation and outcomes of SARS-CoV-2 infection in this patient group from March 2020 to December 2021. RESULTS: 220 patients were included, 48 were found to have experienced COVID-19. There was no significant difference regarding age, gender, underlying kidney disease, CKD stage, dialysis status, type or number of immunosuppressive medications, and glomerular filtration rate between patients with and without COVID-19. Most were infected by a household member (43.8%) and during outpatient or inpatient care (18.8%). Four (8.3%) were asymptomatic, and 43 (89.6%) had mild infection. Severe COVID-19 was observed in only one patient. Eleven (22.9%) patients with COVID-19 were previously vaccinated. Acute kidney injury was detected in 4 (8.3%); as stage 1 in all. Median follow-up after COVID-19 was 4.6 months. All patients fully recovered, and no renal disease flare or death was observed. CONCLUSIONS: Although the vaccination rate was low in our cohort, the majority of the children with COVID-19 showed a mild course. Along with the vaccination, general precautions seemed to be successful for this population.

COVID-19 vaccination among adolescents and young adults with chronic kidney conditions: a single-center experience.

BACKGROUND: Following the pandemic of COVID-19, the main focus has been on COVID-19 vaccines and herd immunity. Although the safety of the COVID-19 vaccines has been shown in clinical trials, children with chronic diseases were not included. We investigated the side effect profile and safety of the COVID-19 vaccines in adolescents with kidney disease. METHODS: A questionnaire including demographic information, history of COVID-19, vaccination status, and vaccine-related side effects was administered to the patients with chronic kidney disease (CKD) stage 2-5, glomerular disease treated with immunosuppression, and kidney transplant recipients. RESULTS: Ninety-eight patients were vaccinated with CoronaVac-inactivated SARS-CoV-2 (n=16) or BNT162b2 messenger RNA (mRNA) COVID-19 (n=82) vaccine. The mean age was 16.90±2.36 years. The most common side effects were local pain, fatigue, and fever. No serious side effects or renal disease flare were observed. There was no significant difference in the side effects reported after the BNT162b2 mRNA-RNA as compared to the Corona Vac-inactivated SARS-CoV-2 vaccine. No significant relationship was found between the frequency of side effects according to age, glomerular filtration rate, immunosuppressive treatments, CKD stage, and the underlying disease. CONCLUSION: Although the reported data are subjective because they were obtained through a questionnaire and studies with long-term follow-up are needed, our early experience suggests that the vaccine is safe and adolescents and young adults should be encouraged to be vaccinated.

Hearing Loss Related to Gene Mutations in Distal Renal Tubular Acidosis.

INTRODUCTION: Distal renal tubular acidosis (dRTA) is a disease that may develop either primarily or secondarily, resulting from urinary acidification defects in distal tubules. Hearing loss may accompany primary forms of dRTA. This study aims to determine the characteristics of hearing loss due to different gene mutations in patients with dRTA. METHODS: Behavioral and electrophysiological audiological evaluations were performed after otolaryngology examination in 21 patients with clinically diagnosed dRTA. Radiological imaging of the inner ear (n = 9) was conducted and results of genetic analyses using next-generation sequencing method (n = 16) were included. RESULTS: Twenty-one patients with dRTA from 20 unrelated families, aged between 8 months and 33 years (median = 12, interquartile range = 20), participated. All patients with ATP6V1B1 mutations (n = 9) had different degrees of hearing loss. There was one patient with hearing loss in patients with ATP6V0A4 mutations (n = 6). One patient with the WDR72 mutation had normal hearing. Large vestibular aqueduct syndrome (LVAS) was detected in 6 (67%) of 9 patients whose radiological evaluation results were available. CONCLUSIONS: LVAS is common in patients with dRTA and may influence the type and severity of hearing loss in these patients. The possibility of both congenital and late-onset and progressive hearing loss should be considered in dRTA patients. A regular audiological follow-up is essential for the early detection of a possible late-onset or progressive hearing loss in these patients.

Predictors of kidney complications and analysis of hypertension in children with allogeneic hematopoietic stem cell transplantation.

BACKGROUND: This study aimed to determine incidence of kidney complications in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) patients. METHODS: Pediatric allogeneic HSCT patients were included. Post-transplantation urinary system complications were collected from medical records and glomerular filtration rates at last visit compared with clinical parameters. Additionally, 24-h ambulatory blood pressure monitoring was performed. RESULTS: The study included 165 pediatric patients. Acute kidney injury (AKI) developed in 125 (75.8%) patients of whom 54 (43.2%) had stage 1, 36 (28.8%) stage 2, and 35 (28%) stage 3 AKI. Primary malignant disease and viral infection post-HSCT were associated with increased risk of AKI (OR: 4; 95%CI: 1.2-13, p = 0.022 and OR: 2.9; 95%CI: 1.2-6.8, p = 0.014, respectively). Mean duration of post-HSCT follow-up was 4.4 ± 2.5 years, during which time 8 patients had chronic kidney disease (CKD) (stage 1, 4 patients; stage 2, 3 patients; stage 3, 1 patient). CKD incidence was higher in patients in whom stem cell product was bone marrow + cord blood and mobilized peripheral blood, compared to bone marrow alone (40-37.5% versus 5.1%, p = 0.002). Based on 24-h ABPM, 14.7% and 7.4% of patients with normal office blood pressure had pre-hypertension and hypertension, respectively. In patients with albuminuria/severe albuminuria, daytime and nighttime systolic SDS scores were higher than those without albuminuria/severe albuminuria (p = 0.010 and p = 0.004, respectively). CONCLUSIONS: Incidence of AKI is higher in pediatric HSCT patients with primary malignant disease and those with documented viral infection. Our study highlights the beneficial role of 24-h ABPM as a routine part of standard care of pediatric HSCT recipients.

Long-term kidney follow-up after pediatric acute kidney support therapy for children less than 15 kg.

BACKGROUND: In small children, acute dialysis (pediatric acute kidney support therapy (paKST)) is increasingly used; however, it is challenging for many reasons. We compared clinical characteristics and predictors of long-term outcomes of patients < 15 kg on peritoneal dialysis (PD), hemodialysis (HD), and continuous kidney replacement therapy (CKRT). METHODS: Patients with history of paKST (CKRT, HD, PD) weighing < 15 kg and ≥ 6 months of follow-up at Hacettepe University were included. Surviving patients were evaluated at last visit. RESULTS: 109 patients (57 females) were included. Median age at paKST was 10.1 months (IQR: 2-27 months). In total, 43 (39.4%) patients received HD, 37 (34%) PD, and 29 (26.6%) CKRT. 64 (58.7%) patients died a median 3 days (IQR: 2-9.5 days) after paKST. Percentages of patients using vasopressor agents, with sepsis, and undergoing mechanical ventilation were lower in those who survived. After mean follow-up of 2.9 ± 2.1 years, 34 patients were evaluated at mean age 4.7 ± 2.4 years. Median spot urine protein/creatinine was 0.19 (IQR: 0.13-0.37) and 12 patients (35.3%) had non-nephrotic proteinuria. Three patients had estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73m2 and 2 (6%) had hyperfiltration. In total 22 patients (64.7%) had ≥ 1 kidney risk factor (elevated blood pressure/hypertension, hyperfiltration, eGFR < 90 ml/min/1.73m2, and/or proteinuria) at last visit. Among 28 patients on paKST < 32 months, 21 had ≥ 1 risk factor (75%), whereas among 6 patients who had paKST ≥ 32 months, one patient had ≥ 1 risk factor (16.7%), (p = 0.014). CONCLUSIONS: Patients on paKST who undergo mechanical ventilation and vasopressor treatment should be followed-up more closely. After surviving the acute period, patients on paKST need to be followed-up closely during the chronic stage. A higher resolution version of the Graphical abstract is available as Supplementary information.

Metabolomic Analyses to Identify Candidate Biomarkers of Cystinosis.

Cystinosis is a rare, devastating hereditary disease secondary to recessive CTNS gene mutations. The most commonly used diagnostic method is confirmation of an elevated leukocyte cystine level; however, this method is expensive and difficult to perform. This study aimed to identify candidate biomarkers for the diagnosis and follow-up of cystinosis based on multiomics studies. The study included three groups: newly-diagnosed cystinosis patients (patient group, n = 14); cystinosis patients under treatment (treatment group, n = 19); and healthy controls (control group, n = 30). Plasma metabolomics analysis identified 10 metabolites as candidate biomarkers that differed between the patient and control groups [L-serine, taurine, lyxose, 4-trimethylammoniobutanoic acid, orotic acid, glutathione, PE(O-18:1(9Z)/0:0), 2-hydroxyphenyl acetic acid, acetyl-N-formil-5-metoxikinuramine, 3-indoxyl sulphate]. As compared to the healthy control group, in the treatment group, hypotaurine, phosphatidylethanolamine, N-acetyl-d-mannosamine, 3-indolacetic acid, p-cresol, phenylethylamine, 5-aminovaleric acid, glycine, creatinine, and saccharic acid levels were significantly higher, and the metabolites quinic acid, capric acid, lenticin, xanthotoxin, glucose-6-phosphate, taurine, uric acid, glyceric acid, alpha-D-glucosamine phosphate, and serine levels were significantly lower. Urinary metabolomic analysis clearly differentiated the patient group from the control group by means of higher allo-inositol, talose, glucose, 2-hydroxybutiric acid, cystine, pyruvic acid, valine, and phenylalanine levels, and lower metabolite (N-acetyl-L-glutamic acid, 3-aminopropionitrile, ribitol, hydroquinone, glucuronic acid, 3-phosphoglycerate, xanthine, creatinine, and 5-aminovaleric acid) levels in the patient group. Urine metabolites were also found to be significantly different in the treatment group than in the control group. Thus, this study identified candidate biomarkers that could be used for the diagnosis and follow-up of cystinosis.

Oral Coenzyme Q10 supplementation leads to better preservation of kidney function in steroid-resistant nephrotic syndrome due to primary Coenzyme Q10 deficiency.

Primary Coenzyme Q10 (CoQ10) deficiency is an ultra-rare disorder caused by defects in genes involved in CoQ10 biosynthesis leading to multidrug-resistant nephrotic syndrome as the hallmark kidney manifestation. Promising early results have been reported anecdotally with oral CoQ10 supplementation. However, the long-term efficacy and optimal prescription remain to be established. In a global effort, we collected and analyzed information from 116 patients who received CoQ10 supplements for primary CoQ10 deficiency due to biallelic pathogenic variants in either the COQ2, COQ6 or COQ8B genes. Median duration of follow up on treatment was two years. The effect of treatment on proteinuria was assessed, and kidney survival was analyzed in 41 patients younger than 18 years with chronic kidney disease stage 1-4 at the start of treatment compared with that of an untreated cohort matched by genotype, age, kidney function, and proteinuria. CoQ10 supplementation was associated with a substantial and significant sustained reduction of proteinuria by 88% at 12 months. Complete remission of proteinuria was more frequently observed in COQ6 disease. CoQ10 supplementation led to significantly better preservation of kidney function (5-year kidney failure-free survival 62% vs. 19%) with an improvement in general condition and neurological manifestations. Side effects of treatment were uncommon and mild. Thus, our findings indicate that all patients diagnosed with primary CoQ10 deficiency should receive early and life-long CoQ10 supplementation to decelerate the progression of kidney disease and prevent further damage to other organs.

Variation of the clinical spectrum and genotype-phenotype associations in Coenzyme Q10 deficiency associated glomerulopathy.

Primary Coenzyme Q10 deficiency is a rare mitochondriopathy with a wide spectrum of organ involvement, including steroid-resistant nephrotic syndrome mainly associated with disease-causing variants in the genes COQ2, COQ6 or COQ8B. We performed a systematic literature review, PodoNet, mitoNET, and CCGKDD registries queries and an online survey, collecting comprehensive clinical and genetic data of 251 patients spanning 173 published (47 updated) and 78 new cases. Kidney disease was first diagnosed at median age 1.0, 1.2 and 9.8 years in individuals with disease-causing variants in COQ2, COQ6 and COQ8B, respectively. Isolated kidney involvement at diagnosis occurred in 34% of COQ2, 10.8% of COQ6 and 70.7% of COQ8B variant individuals. Classic infantile multiorgan involvement comprised 22% of the COQ2 variant cohort while 47% of them developed neurological symptoms at median age 2.7 years. The association of steroid-resistant nephrotic syndrome and sensorineural hearing loss was confirmed as the distinctive phenotype of COQ6 variants, with hearing impairment manifesting at average age three years. None of the patients with COQ8B variants, but 50% of patients with COQ2 and COQ6 variants progressed to kidney failure by age five. At adult age, kidney survival was equally poor (20-25%) across all disorders. A number of sequence variants, including putative local founder mutations, had divergent clinical presentations, in terms of onset age, kidney and non-kidney manifestations and kidney survival. Milder kidney phenotype was present in those with biallelic truncating variants within the COQ8B variant cohort. Thus, significant intra- and inter-familial phenotype variability was observed, suggesting both genetic and non-genetic modifiers of disease severity.

Long-term renal survival of paediatric patients with lupus nephritis.

BACKGROUND: Childhood-onset systemic lupus erythematosus (SLE) is more severe than adult-onset disease, including more frequent kidney involvement. This study aimed to investigate baseline clinical features, treatment modalities and short- and long-term renal outcomes of paediatric patients with lupus nephritis (LN). MATERIALS AND METHODS: This study enrolled 53 LN patients out of 102 childhood-onset SLE patients followed at Hacettepe University between 2000 and 2020. The demographic and clinical data were reviewed retrospectively from the medical charts and electronic records. All SLE patients with renal involvement underwent renal biopsy either at the time of diagnosis or during follow-up. RESULTS: The median age at onset of SLE was 13.3 years [interquartile range (IQR) 10.4-15.8]. The median follow-up duration was 43.1 months (IQR 24.3-69.3). Of the 102 SLE patients, 53 (52%) had LN. The most frequent histopathological class was Class IV LN (54.7%), followed by Class III (22.6%). The proportion of patients who achieved either complete or partial remission was 77.3% and 73% at 6 and 12 months, respectively. In the overall LN cohort, 5- and 10-year renal survival rates were 92% and 85.7%, respectively. The remission rate at Month 6 was significantly higher in mycophenolate mofetil (MMF)- and cyclophosphamide (CYC)-treated groups than other combination therapies (P = 0.02). Although no difference was found between the CYC and MMF response rates (P = 0.57) in proliferative LN (Classes III and IV), the majority of Class IV patients (79%) received CYC as induction therapy. There was no difference between the response rates in any treatment regimens at Month 12 (P = 0.56). In the multivariate analysis, male gender, requiring dialysis at the time of LN diagnosis and failure to achieve remission at 6 and 12 months were found to be associated with poor renal outcome. CONCLUSIONS: Our study demonstrated that male gender, failure to achieve remission at 6 and 12 months and requiring dialysis at the time of diagnosis were the best predictors of poor renal outcome. Therefore appropriate and aggressive management of paediatric LN is essential to achieve and maintain remission.

A broad clinical spectrum of PLCε1-related kidney disease and intrafamilial variability.

BACKGROUND: The phenotypic and genotypic spectrum and kidney outcome of PLCε1-related kidney disease are not well known. We attempted to study 25 genetically confirmed cases of PLCε1-related kidney disease from 11 centers to expand the clinical spectrum and to determine the relationship between phenotypic and genotypic features, kidney outcome, and the impact of treatment on outcome. METHODS: Data regarding demographics, clinical and laboratory characteristics, histopathological and genetic test results, and treatments were evaluated retrospectively. RESULTS: Of 25 patients, 36% presented with isolated proteinuria, 28% with nephrotic syndrome, and 36% with chronic kidney disease stage 5. Twenty patients underwent kidney biopsy, 13 (65%) showed focal segmental glomerulosclerosis (FSGS), and 7 (35%) showed diffuse mesangial sclerosis (DMS). Of the mutations identified, 80% had non-missense, and 20% had missense; ten were novel. No clear genotype-phenotype correlation was observed; however, significant intrafamilial variations were observed in three families. Patients with isolated proteinuria had significantly better kidney survival than patients with nephrotic syndrome at onset (p = 0.0004). Patients with FSGS had significantly better kidney survival than patients with DMS (p = 0.007). Patients who presented with nephrotic syndrome did not respond to any immunosuppressive therapy; however, 4/9 children who presented with isolated proteinuria showed a decrease in proteinuria with steroids and/or calcineurin inhibitors. CONCLUSION: PLCε1-related kidney disease may occur in a wide clinical spectrum, and genetic variations are not associated with clinical presentation or disease course. However, clinical presentation and histopathology appear to be important determinants for prognosis. Immunosuppressive medications in addition to angiotensin-converting enzyme inhibitors may be beneficial for selected patients. "A higher resolution version of the Graphical abstract is available as Supplementary information".

Transplantation in pediatric aHUS within the era of eculizumab therapy.

aHUS is caused by the over-activation and dysregulation of the alternative complement pathway. Data regarding outcomes of pediatric aHUS patients after kidney transplantation are still very scarce. Accordingly, the aim of this study was to describe the clinical findings and outcomes of pediatric aHUS patients after renal transplantation. This is a retrospective, multicenter study including 12 patients from the national registry system. Among the 12 patients, eight had received prophylactic eculizumab and none of those patients (except one) had experienced aHUS recurrence during a median follow-up period of 58.5 (min-max, 4-94) months. Although eculizumab had been started on the day before transplantation in one of them, aHUS recurrence occurred during the transplantation procedure. Eculizumab had been stopped in only one patient who had no complement gene mutation after 35 months of therapy, and recurrence had not been observed during the 19 months of follow-up. In three patients, maintenance doses had been spaced out without any recurrence. One additional patient with anti-CFH antibody received only two doses of eculizumab for transplantation and had been followed for 46 months without aHUS recurrence. The remaining three patients had not received anti-C5 therapy and none of those patients experienced aHUS recurrence during a median follow-up period of 21 (min-max, 9-42) months. Prophylactic eculizumab is a safe and effective treatment for the prevention of aHUS recurrence. Eculizumab interval prolongation, discontinuation, and transplantation without eculizumab prophylaxis can be tried in selected patients with close follow-up.

Clinical practice recommendations for recurrence of focal and segmental glomerulosclerosis/steroid-resistant nephrotic syndrome.

Recurrence of primary disease is one of the major risks for allograft loss after pediatric RTx. The risk of recurrence of FSGS/SRNS after pediatric RTx in particular can be up to 86% in idiopathic cases. There is a need for consensus recommendations on its prevention and treatment. The CERTAIN study group has therefore performed a thorough literature search based on the PICO model of clinical questions to formulate educated statements to guide the clinician in the process of decision-making. A set of educated statements on prevention and treatment of FSGS/SRNS after pediatric RTx has been generated after careful evaluation of available evidence and thorough panel discussion. We do not recommend routine nephrectomy prior to transplantation; neither do we recommend abstaining from living donation. Special attendance needs to be given to those patients who had already experienced graft loss due to FSGS/SRNS recurrence. Early PE or IA with or without high-dose CsA and/or rituximab seems to be most promising to induce remission. The educated statements presented here acknowledge that FSGS/SRNS recurrence after pediatric RTx remains a major concern and is associated with shorter graft survival or even graft loss. The value of any recommendation needs to take into account that evidence is based on cohorts that differ in ethnicity, pre-transplant history, immunosuppressive regimen, definition of recurrence (eg, clinical and/or histological diagnosis) and treatment modalities of recurrence.

Favipiravir use in children with COVID-19 and acute kidney injury: is it safe?

BACKGROUND: The rising number of infections due to Severe Acute Respiratory Syndrome Coronavirus-2 (popularly known as COVID-19) has brought to the fore new antiviral drugs as possible treatments, including favipiravir. However, there is currently no data regarding the safety of this drug in patients with kidney impairment. The aim of this paper, therefore, is to share our experience of the use of favipiravir in pediatric patients affected by COVID-19 with any degree of kidney impairment. METHODS: The study enrolled pediatric patients aged under 18 years and confirmed as suffering from COVID-19 and multisystem inflammatory syndrome in children (MIS-C) with any degree of kidney injury, who were treated with favipiravir at the time of admission. RESULTS: Out of a total of 11 patients, 7 were diagnosed with MIS-C and 4 with severe COVID-19. The median age of the cases was 15.45 (9-17.8) years and the male/female ratio was 7/4. At the time of admission, the median serum creatinine level was 1.1 mg/dl. Nine patients were treated with favipiravir for 5 days, and 2 patients for 5 days followed by remdesivir for 5-10 days despite kidney injury at the time of admission. Seven patients underwent plasma exchange for MIS-C while 2 severely affected cases underwent continuous kidney replacement therapy (CKRT) as well. One severe COVID-19 patient received plasma exchange as well as CKRT. Serum creatinine values returned to normal in mean 3.07 days. CONCLUSIONS: Favipiravir seems a suitable therapeutic option in patients affected by COVID-19 with kidney injury without a need for dose adjustment.

Predictors for the use of herbal and dietary supplements in children and adolescents with kidney and urinary tract diseases.

Complementary and alternative medicine are treatments administered alone or in combination with conventional medical treatments. Data on complementary and alternative medicine use in children with kidney and urinary tract diseases are limited. In this cross-sectional study, the frequency and preferred methods of complementary and alternative medicine use and factors associated with their use were evaluated in 201 patients (48% female; median age, 11 years; median disease duration, 5.1 years) with kidney and urinary tract diseases and 260 healthy (without chronic disease) controls. Data were collected through a questionnaire-based interview and patients' medical records. Herbal and dietary supplements, including fish oil, were the most commonly used complementary and alternative medicine agents in both groups. There was no difference in herbal and dietary supplement use between the groups when fish oil was excluded (29% vs. 28%; p = 0.88). Herbal and dietary supplements were mainly used to improve/mitigate renal disease (52%). Logistic regression analysis revealed that disease duration > 7 years (odds ratio (OR), 3.70; 95% confidence interval (CI), 1.48-9.20), current use of six or more drugs (OR, 5.6; 95% CI, 1.28-24.41), and recurrent urinary tract infection or nephrolithiasis (OR, 3.92; 95% CI, 1.02-15.09) were the independent risk factors for herbal and dietary supplement use, except fish oil. Middle socioeconomic status was associated with decreased herbal and dietary supplement use, except fish oil, compared with low socioeconomic status (OR, 0.30; 95% CI, 0.11-0.81). Herbal and dietary supplements were used by 78% patients, despite knowing that these products could have side effects; only 42% of the patients shared the information about herbal and dietary supplement use with their doctors.Conclusion: Herbal and dietary supplement use is frequent in children with kidney and urinary tract diseases. Educating health professionals regarding such use is mandatory for developing strategies to prevent critical consequences. What is Known: • Complementary and alternative medicine (CAM) practices are therapeutic approaches that do not have sufficient efficacy and safety evidence. • CAM is widely used in healthy children and in certain chronic diseases. What is New: • Herbal and dietary supplements (HDSs) were the most commonly used method in kidney and urinary tract diseases. • Duration of disease, number of drugs, and socioeconomic status are determinants of HDS use except fish oil.

Cystinosis beyond kidneys: gastrointestinal system and muscle involvement.

BACKGROUND: Cystinosis is a multisystemic disease resulting from cystine accumulation primarily in kidney and many other tissues. We intended to study the evolution of less commonly seen extrarenal complications of cystinosis in a group of patients who have periods without cysteamine treatment. METHODS: Gastrointestinal and muscular complications of cystinosis were studied in a group of 21 patients. RESULTS: Twenty one patients were included in the study. Among them, 14 were homozygous and 3 were compound heterozygous for CTNS mutations. The median age of diagnosis was 15 months (range; 5 months-14 years) and the mean age at last visit was 11.3 ± 6.5 years. Nine patients (42%) had end stage renal disease at a mean age of 10.6 years (6.5-17 years). Abdominal ultrasonography and portal vein doppler ultrasonography were performed in19 patients, 14 of them (74%) had hepatomegaly, 10 patients (53%) had granular pattern or heterogeneity of liver. Only one patient had high transaminase levels and liver biopsy showed cystine crystals in the liver. Eleven patients (58%) had borderline or increased portal vein minimum and maximum flow velocities. One patient had CK level of 9024 U/L and electromyographic study showed active myopathic involvement. Two patients were found to have gastroesaphageal reflux only and 4 patients were found to have esophageal remnants in addition to reflux. CONCLUSIONS: In addition to renal functions, extrarenal organs may be affected from cystine accumulation even in childhood, especially in patients who are incompliant to treatment, resulting in complications such as swallowing difficulty, hepatomegaly and portal hypertension.