Metabolic effects of high diet acid load (DAL) have been studied for years in adults, although only recently in children. Contemporary diets, especially those of Western societies, owe their acidogenic effect to high animal-origin protein content and low contribution of base-forming elements, such as fruits and vegetables. This imbalance, where dietary acid precursors exceed the body's buffering capacity, results in an acid-retaining state known by terms such as "eubicarbonatemic metabolic acidosis," "low-grade metabolic acidosis," "subclinical acidosis," or "acid stress". Its consequences have been linked to chronic systemic inflammation, contributing to various noncommunicable diseases traditionally considered more common in adulthood, but now have been recognized to originate at much earlier ages. In children, effects of high DAL are not limited to growth impairment caused by alterations of bone and muscle metabolism, but also represent a risk factor for conditions such as obesity, insulin resistance, diabetes, hypertension, urolithiasis, and chronic kidney disease (CKD). The possibility that high DAL may be a cause of chronic acid-retaining states in children with growth impairment should alert pediatricians and pediatric nephrologists, since its causes have been attributed traditionally to inborn errors of metabolism and renal pathologies such as CKD and renal tubular acidosis. The interplay between DAL, overall diet quality, and its cascading effects on children's health necessitates comprehensive nutritional assessments and interventions. This narrative review explores the clinical relevance of diet-induced acid retention in children and highlights the potential for prevention through dietary modifications, particularly by increasing fruit and vegetable intake alongside appropriate protein consumption.

In patients with steroid-resistant nephrotic syndrome (SRNS), the presence of monogenic variants influences therapeutic strategies. Large cohort studies reported the detection of monogenic variants in approximately 30% of patients with SRNS. However, these cohorts included many patients, such as those with symptomatic proteinuria, who did not meet the strict diagnostic criteria for pediatric nephrotic syndrome (NS). Therefore, we investigated the proportion of causative monogenic variants detected in patients who strictly met the diagnostic criteria of SRNS and explored their clinical characteristics. We examined pediatric SRNS cases with genetic analysis conducted in our hospital. Cases satisfying all of the following criteria were included: (1) age at onset 1-18years, (2) serum albumin at onset ≤ 2.5g/dl, (3) persistent heavy proteinuria, and (4) no complete remission after 4weeks of steroid monotherapy. The proportion of detected monogenic variants was 12% (22/185) among all patients. The proportion was only 7% (9/129) in patients with edema at disease onset compared with 38% (9/24) in those without (p < 0.0001). Monogenic variants were rare in patients with acute kidney injury associated with NS (1% (1/11)) or a history of complete remission (4% (2/51)). Our study revealed a monogenic cause in 12% of individuals with strictly defined SRNS, a much smaller proportion than previously reported. The presence or absence of edema at the onset was an important factor to distinguish SRNS with monogenic cause from SRNS without. Our results provide further evidence of the SRNS types attributable to monogenic causes.

Cardiopulmonary bypass (CPB) is associated with hemolysis and acute kidney injury (AKI). The study aim was to determine if urine dipstick blood in infants after CPB was associated with AKI and urine neutrophil gelatinase-associated lipocalin (NGAL). Infants who underwent CPB at a single center were enrolled prospectively between October 2017 and June 2019. Urine samples prior to CPB and 6h after CPB cessation were analyzed in batch for NGAL and dipstick blood. AKI was defined using creatinine-based KDIGO criteria within 72h of CPB. Spearman correlation examined associations between urine dipstick blood and NGAL at each time point. Linear regression estimated the associations between urine dipstick blood and log-transformed NGAL 6h after CPB. Logistic regression estimated associations and compared discrimination between urine dipstick blood and NGAL for predicting AKI. At baseline, 7/63 samples (11%) had > trace blood. Six hours after CPB, 62/98 samples (63%) had > trace blood and 26% had 3 + (large) blood. In total, 18/98 (18%) with a 6-h post-CPB sample had postoperative AKI. Urine dipstick blood values correlated with urine NGAL 6h after CPB (r = 0.52, p < 0.01), but not at baseline (r = 0.06, p = 0.66). Those with 3 + (large) blood on urine dipstick had 6 times higher mean NGAL values compared to those with negative/trace blood (mean ratio 6.6, 95%CI 3.1-14.4, p < 0.01). Those with 3 + (large) blood had 8 times higher odds of AKI (OR 7.99, 95%CI 1.5-41.9, p = 0.01). Urine dipstick blood post CPB may be a simple and inexpensive tool to help predict AKI in infants.

Access to pediatric dialysis is challenged in low-resource settings due to high costs, scarcity of equipment, and the lack of qualified personnel availability. We demonstrated the manual single lumen alternating micro-batch (mSLAMB) device can remove small solutes in vitro without the need for electricity, batteries, or pumps. We developed a new version (Kirpa Kit™) to address some of the technical limitations of mSLAMB. Here, we compare the in vitro clearance performance and ease of use of the Kirpa Kit™ with that of prior mSLAMB configurations. A mixture of expired packed red blood cells, 0.9% NaCl, urea, and heparin was used to test the efficiency of two mSLAMB configurations and the Kirpa Kit™ in removing potassium and urea. Clearance was evaluated by measuring percent reduction after 25-min sessions with each device. A survey was used to evaluate the ease of use of each configuration. The Kirpa Kit™ achieved a median urea reduction of 82.4% and potassium reduction of 82.1%, which were higher than those achieved with the best-performing mSLAMB configuration (urea 71.9%, potassium 75.4%). The Kirpa Kit™ was easier to use with a shorter perceived time of use than the mSLAMB. The Kirpa Kit™, evolution of mSLAMB, is easy to use and may have improved efficacy, making it an optimal candidate for in vivo testing.

BK polyomavirus (BKV) infection is a critical complication hindering graft survival after kidney transplantation. We aimed to investigate the risk factors and outcome of BKV infection in pediatric kidney transplantation. The clinical and follow-up data of pediatric kidney transplant recipients at the Children's Hospital of Fudan University from Jan 2015 to June 2023 were retrospectively analyzed. A total of 217 patients were included in the study with mean follow-up time of 24.3 ± 19.9 months. The mean age at transplantation was 9.7 ± 4.2years. The patient survival rate and graft survival rate were 98.2% and 96.8%, respectively. Twenty-nine patients (13.4%) developed BKV infection, which was detected at 5.8 ± 3.2months after transplantation. Among these 29 patients with BKV infection, 8 patients (3.6%) developed BKV nephropathy (BKVN), which was diagnosed at 8.3 ± 2.9months after transplantation, and 2 patients developed graft failure eventually. Compared with the non-BKV infection group (eGFR 76.7 ± 26.1mL/min/1.73 m2) and BKV infection without BKVN group (eGFR 85.2 ± 23.8mL/min/1.73 m2), BKVN group had lowest eGFR during follow-up (33.5 ± 11.0ml/min/1.73 m2, P < 0.001). Younger age at transplant (OR 0.850, 95%CI 0.762-0.948, P = 0.005), CAKUT disease of primary etiology (OR 2.890, 95%CI 1.200-6.961, P = 0.018), and CMV negative recipient serostatus before transplantation (OR 3.698, 95%CI 1.583-8.640, P = 0.003) were independent risk factors for BKV infection. Incidence of BKV infection is quite high within 12months after pediatric kidney transplantation and children with BKVN have poor graft function. Younger age at transplant, CAKUT disease, and CMV negative recipient serostatus before transplantation increase the risk of BKV infection after kidney transplantation.

Training caregivers performing PD is an important measure to prevent peritonitis. A low literacy rate hinders training in low-resource settings. We designed a structured training initiative (STI) and objective structured assessment (OSA) using visual and kinesthetic resources with minimal use of written resources. We studied the impact of STIs on caregivers' knowledge and practical skills and the rate of peritonitis. This prospective study conducted initial STI (iSTI) for caregivers of children initiating PD and retraining STI (rSTI) for those already on PD. OSA was administered after completion of training, and those scoring < 95% were retrained. Re-assessment was done at 3, 6, and 12months, and those who scored < 95% underwent re-training. The rate of PD peritonitis and the time to first peritonitis were compared between the STI group and the cohort on PD in our center who received standard training before STI (controls). Caregivers of 40 children were included. The median duration of iSTI and rSTI was 19.5 (18, 20) and 9 (9, 9.5) hrs, and the OSA scores were 97% (97%, 98%) and 96% (96%, 98%), respectively. Only 5% required retraining. There was a significant reduction in the rate of PD peritonitis (0.29 vs. 0.69 episodes/patient-year; p < 0.001) and longer time to peritonitis (189 vs. 69days; p < 0.001) in the STI group when compared to the controls (n = 32). STI was effective in training caregivers for peritoneal dialysis. There was a reduction in the rate of peritonitis and a longer time to first peritonitis in the STI cohort.

Continuous kidney replacement therapy (CKRT) has recently become the preferred kidney replacement modality for children with acute kidney injury (AKI). We hypothesise that CKRT technical parameters and treatment settings in addition to the clinical characteristics of patients may influence the circuit lifetime in children. The study involved children included in the EurAKId registry (NCT02960867), who underwent CKRT treatment. We analysed patient characteristics and CKRT parameters. The primary end point was mean circuit lifetime (MCL). Secondary end points were number of elective circuit changes and occurrence of dialysis-related complications. The analysis was composed of 247 children who underwent 37,562h of CKRT (median 78, IQR 37-165h per patient). A total of 1357 circuits were utilised (3, IQR 2-6 per patient). MCL was longer in regional citrate anticoagulation (RCA), compared to heparin (HA) and no anticoagulation (NA) (42, IQR 32-58h; 24, IQR 14-34h; 18, IQR 12-24h, respectively, p < 0.001). RCA was associated with longer MCL regardless of the patient's age or dialyser surface. In multivariate analysis, MCL correlated with dialyser surface area (beta = 0.14, p = 0.016), left internal jugular vein vascular access site (beta = -0.37, p = 0.027), and the use of HA (beta = -0.14, p = 0.038) or NA (beta = -0.37, p < 0.001) vs. RCA. RCA was associated with the highest ratio of elective circuit changes and the lowest incidence of complications. Anticoagulation modality, dialyser surface, and vascular access site influence MCL. RCA should be considered when choosing first-line anticoagulation for CKRT in children. Further efforts should focus on developing guidelines and clinical practice recommendations for paediatric CKRT.

Pediatric blood pressure (BP) assessment and management is increasingly important. Uncontrolled systolic and combined hypertension leads to hypertension-mediated organ damage. The impact of isolated diastolic hypertension is less clearly understood. We analyzed the prevalence of ambulatory isolated diastolic hypertension (IDH) in primary (PH) and secondary (SH) hypertension, and associations with BMI Z-score (BMIz) and left ventricular mass index adjusted to the 95th percentile (aLVMI) in a large, multicenter cohort of hypertensive children. Hypertensive children were divided and analyzed in three ambulatory hypertension subgroups: 24-h, daytime, and nighttime. Specifically, we sought to determine the prevalence of ambulatory 24-h, daytime, or nighttime IDH. Prevalence of IDH varied based on ambulatory phenotypes, ranging from 6 to 12%, and was highest in children with SH. Children with IDH tended to be more likely female and, in some cases, were leaner than those with isolated systolic hypertension (ISH). Despite previous pediatric studies suggesting no strong association between diastolic blood pressure and left ventricular hypertrophy (LVH), we observed that children with IDH were equally likely to have LVH and had comparable aLVMI to those with ISH and combined systolic-diastolic hypertension. In summary, ambulatory IDH appears to be a unique phenotype with a female sex, and younger age predilection, but equal risk for LVH in children with either PH or SH.