Acute kidney injury in children hospitalised for febrile urinary tract infection

AIM

To determine (i) prevalence and the risk factors for acute kidney injury (AKI) in children hospitalised for febrile urinary tract infection (fUTI) and (ii) role of AKI as indicator of an underlying VUR. AKI, in fact, is favoured by a reduced nephron mass, often associated to VUR.

METHODS

This retrospective Italian multicentre study enrolled children aged 18 years or younger (median age = 0.5 years) discharged with a primary diagnosis of fUTI. AKI was defined using Kidney Disease/Improving Global Outcomes serum creatinine criteria.

RESULTS

Of 849 children hospitalised for fUTI (44.2% females, median age 0.5 years; IQR = 1.8), 124 (14.6%) developed AKI. AKI prevalence rose to 30% in the presence of underlying congenital anomalies of the kidney and urinary tract (CAKUT). The strongest AKI predictors were presence of CAKUT (OR = 7.5; 95%CI: 3.8-15.2; p = 9.4e-09) and neutrophils levels (OR = 1.13; 95%CI: 1.08-1.2; p = 6.8e-07). At multiple logistic regression analysis, AKI during fUTI episode was a significant indicator of VUR (OR = 3.4; 95%CI: 1.7-6.9; p = 0.001) despite correction for the diagnostic covariates usually used to assess the risk of VUR after the first fUTI episode. Moreover, AKI showed the best positive likelihood ratio, positive predictive value, negative predictive value and specificity for VUR.

CONCLUSION

AKI occurs in 14.6% of children hospitalised for fUTI and is a significant indicator of VUR.

Outcome of immunosuppression in children with IgA vasculitis-related nephritis

BACKGROUND AND HYPOTHESIS

IgA vasculitis with nephritis (IgAVN) is the most common vasculitis in children. Treatment recommendations are, due to a lack of evidence, based on expert opinion resulting in variation. The aim of this study was to describe clinical presentation, treatment and outcome of an extremely large cohort of children with biopsy proven IgAVN to identify prognostic risk factors and signals of treatment efficacy.

METHODS

Retrospective data were collected on 1148 children with biopsy proven IgAVN between 2005 and 2019 from 41 international paediatric nephrology centres across 25 countries and analyzed using multivariate analysis. The primary outcome was estimated glomerular filtration rate (eGFR) and persistent proteinuria at last follow up.

RESULTS

The median follow up was 3.7 years (IQR 2-6.2). At last follow up, 29% of patients had an eGFR < 90 ml/min/1.73m2, 36% had proteinuria and 3% had chronic kidney disease stage 4-5. Older age, lower eGFR at onset, hypertension and histological features of tubular atrophy and segmental sclerosis were predictors of poor outcome. There was no evidence to support any specific second line immunosuppressive regimen to be superior to others, even when further analysing subgroups of children with reduced kidney function, nephrotic syndrome or hypoalbuminemia at onset. Delayed start of immunosuppressive treatment was associated with a lower eGFR at last follow up.

CONCLUSION

In this large retrospective cohort, key features associated with disease outcome are highlighted. Importantly there was no evidence to support that any specific immunosuppressive treatments were superior to others. Further discovery science and well-conducted clinical trials are needed to define accurate treatment and improve outcomes of IgAVN.

Pediatric Minimal Change Disease and AKI following the Pfizer-BioNTech COVID-19 Vaccine: causal or incidental correlation?

The global coronavirus 2019 (COVID-19) pandemic required vaccination even in children to reduce infection. We report on the development of acute kidney injury (AKI) and minimal change disease (MCD) nephrotic syndrome (NS), shortly after the first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). A 12-year-old previously healthy boy was referred to our hospital with complaints of peripheral edema and nephrotic range proteinuria. Nine days earlier he had received his first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). Seven days after injection, he developed leg edema, which rapidly progressed to anasarca with significant weight gain. On admission, serum creatinine was 1.3 mg/dL and 24-hour urinary protein excretion was 4 grams with fluid overload. As kidney function continued to decline over the next days, empirical steroid treatment and renal replacement therapy with ultrafiltration were started and kidney biopsy was performed. Seven days after steroid therapy, kidney function began to improve, gradually returning to normal. The association of MCD, nephrotic syndrome and AKI hasn't been previously described following the Pfizer-BioNTech COVID-19 vaccine in pediatric population, but this triad has been reported in adults. We need further similar case reports to establish the real incidence of this possible vaccine side effect.

Polystyrene nanoplastics affect the human ubiquitin structure and ubiquitination in cells: a high-resolution study

Humans are estimated to consume several grams per week of nanoplastics (NPs) through exposure to a variety of contamination sources. Nonetheless, the effects of these polymeric particles on living systems are still mostly unknown. Here, by means of CD, NMR and TEM analyses, we describe at an atomic resolution the interaction of ubiquitin with polystyrene NPs (PS-NPs), showing how a hard protein corona is formed. Moreover, we report that in human HeLa cells exposure to PS-NPs leads to a sensible reduction of ubiquitination. Our study overall indicates that PS-NPs cause significant structural effects on ubiquitin, thereby influencing one of the key metabolic processes at the base of cell viability.

P1814ATYPICAL FEATURES IN A TYPICAL DISEASE: ONE THOUSANDS FACES OF IGA NEPHROPATHY IN PAEDIATRIC PATIENTS

Background and Aims

Immunoglobulin A Nephropathy (IgAN) is the most common cause of idiopathic glomerulonephritis in paediatric patients.

The typical presentation is characterized by recurrent episodes of macroscopic haematuria or persistent microhaematuria with mild or overt proteinuria. Renal function is normally preserved, though a slow progression to chronic kidney disease (CKD) may occur.

However, in rare cases IgAN may assume atypical features, presenting with nephrotic syndrome (NS), acute kidney injury (AKI) or assuming the characteristic of a rapidly progressive glomerulonephritis, leading to significant difficulties in management and critical impact on prognosis.

Method

Of total 756 renal biopsies performed in our centre from 2000 till 2019, 174 (23%) diagnosis of IgA nephropathy were made: 123 (70,6%) of 174 with a milder histological stage (I or II according to Lee’s) and 51 (29,3%) with severe stages (III-IV).

Clinical onset of these 51 patients was mostly characterized by a nephritic syndrome with micro-macrohaematuria, though in 7 of them it assumed atypical features (table 1).

Results

Patients 1, 2, 3 and 4 showed a rapidly progressive IgAN with extensive crescentic lesions at histological evaluation.

In all of the four patients the onset of the disease was characterised by a compromised renal function, thought, according to the medical history, in patients 2 and 4 clinical signs of nephropathy had started some months before the first medical evaluation.

This detail, considering the poorer clinical outcome of patients 2 and 4 (table 1), strongly highlights the need of promptness in the treatment of these conditions.

Patient 1 achieved a complete remission after steroid pulse therapy (Pozzi scheme), while for patients 2,3,4 an additional immunosuppressive treatment was required.

The nephropathy of patient 5 was, instead, characterized by AKI with consistent macrohaematuria. Interestingly, the severity of the clinical presentation was not related to the glomerular lesion (the histology showed a minimal change disease), rather to the intra-tubular haemorrhage, causing an obstructive acute kidney injury. Patient 5 achieved a complete remission after steroid treatment.

The onset of IgAN in patients 6 and 7 was characterized by a nephrotic syndrome, which is a very uncommon feature (&lt;2% of all IgAN).

Patient 6, who showed a massive proteinuria (till 11 grams/24 hours) was promptly treated with steroid and tacrolimus, achieving a complete remission in 6 moths.

Patient 7, a sri-lankan girl, was diagnosed in 2008 in Sri-Lanka.

She underwent treatment with steroid and Mycophenolate and successively, for the persistence of proteinuria, with Cyclosporine A.

From 2014 she has been followed by our centre. Despite a second cycle with Cyclosporine she has shown a persistence of proteinuria and a slow progression to CKD.

Conclusion

This study highlights that a typical disease like IgAN may hide behind an atypical and severe presentation.

Moreover, the blackboard of the atypical forms is extremely heterogeneous, stretching from NS to crescentic and progressive diseases.

As a consequence, the treatment of these conditions is not codified and represents an important challenge for the clinician.

This calls for multicentric studies which could provide shared recommendation for the management of these atypical forms of IgAN.

P0165HYPERTENSION IN OVERWEIGHT AND OBESE CHILDREN: IMPACT ASSESMENT OF ABPM PARAMETERS

Background and Aims

We describe the relationship between overweight and obesity and Hypertension on ABPM.

Method

We conducted a cross-sectional study using a database of patients aged 6-16 years, who had undergone 24h ABPM from December 2002 through December 2016. ABPM were performed using the validated device Spacelab 90217. Were evaluated the 24h MAP, daytime MAP, nocturnal MAP, systolic and diastolic load, MAP Systolic and Diastolic. Subjects were grouped by BMI Z-score into overweight (&gt;1&lt;2), obese (BMI Z-score &gt;2&lt;3) and severe obese (BMI Z-score &gt;3). A total of 1016 patients were enrolled and recorded n.1210 ABPMs. Obese pts were 202 (19.8%); 126 M;76F;median age 10,2 y. Overweight childrens were 97 (11.9%);52 M;45F;median age 8,4y.

Results

Among overweight childrens (BMI Z-Score &gt;1&lt;2): 12 (12.3%) had hypertension, 22 (22.6%) pre-hypertension, 15 (15.4%) MH; non dipping pattern was recorded in 26 (52%). 48 were normotensive. Among obese childrens, 122 had hypertension (60.3%): 24 pts had Masked Hypertension (19.6%); 72 (59.0%) had severe ambulatory hypertension with BMI z-score &gt;3 (mean 3.8) ,and in this category all pts were both systolic and diastolic non dipping. 32 (64%) obese with BMI z-score &gt;2, &lt;3 were non-dipping. Diastolic load was significantly higher (p&gt;0,0001) in severe obese. 28 pts had ambulatory prehypertension (13.8%), 11 pts had White Coat Hypertension (4.9%).41 pts had normotension (20.2%).

Conclusion

The severity of ambulatory hypertension increased with increased BMI Z-score. The non-dipping status is associated, not only with higher BMI Z-score, but was present in overweight and obese with BMI z-score &gt;2&lt;3 also. ABPM is an effective tool that should become routine in all obese patient, but also in overweight childrens, which may lead to better treatments and prevention methods.

P1369ACUTE EXTRACORPOREAL DIALYSIS USING TWO-WAY PICC POWER INJECTABLE IN YOUNG CHILDREN

Background and Aims

Acute extracorporeal dialysis is a short treatment, performed by a central venous catheter of large size, ensuring high flow. These devices have limitations: high caliber, excessive length, impossibility of tunneling and exit-site location in the supraclavicular region, with a subsequent high risk of dislocation and contamination. The authors report a new approach to dialytic central venous catheters selection in children.

Method

From January 2013 to December 2017, 16 children weighing less than 15 kg needed acute extracorporeal dialysis. Patients received an ultrasound guided percutaneous implantation of a two-way PICC power injectable catheter, in the right internal jugular vein or in the anonymous right vein. The device size always respected the ratio of 1/3; the catheters were cut to be adapted to child height, and subclavear tunnelizations and stabilizations were ensured. The hemodialysis was performed with the Prismaflex Gambro system. The effectiveness of treatment was evaluated by recirculation test and by measuring the KT/Vat the third hour, expressing the dialysis adequacy.

Results

Two-way power injectable central venous catheter,sized from 5 to 7 Fr and long from 8 to 15 cm were used. The recorded blood flow ranged from 4.7ml/min/kg to 7ml/min/kg; a KT/V variable from 0.5 to 1 was detected; the recycling rate was between 32% and 40%. No catheter related complications were observed.

Conclusion

In children weighing less than 15 kg, PICC power injectable have lower blood flow and higher recirculation rate compared to traditional dialysis catheters. However, the dialytic adequacy was suitable for an acute hemodialysis treatment. In addition, these catheters are available in a wide range of calibers and result more adaptable to the venous system of younger children.

P1831ABPM DIFFERENCE BETWEEN OBESE AND NON OVERWEIGHT HYPERTENSIVE CHILDREN

Background and Aims

The goal of our study was to analyze the difference in ABPM pattern in overweight and non overweight hypertensive children

Method

The ABPM were performed using Spacelab 90207 and recorded over 24h.Readings were taken every 15 minutes while awake,and every 20 minutes while asleep. In both groups were evaluated the 24h MAP,daytime MAP,nocturnal MAP, systolic and diastolic load,mean 24h SBP and DBP.

A total of 108 pts were enrolled. Pts were divided in two groups.In the first group 54 pts non overweight with primary hypertension:33 male and 21 female with mean age of 10.4 y. In the second group the obese hypertensive children, with mean age of 10.5 y, were divided into two subgroups according to BMI Z-scores:subgroup 1 BMI Z-score &gt;2&lt;3 n 40 pts (17 f;21m); subgroup 2 BMI Z-score &gt;3 n (4f;10m).

Results

Systolic load was significantly higher in obese group (p 0,0409).In obese group n.12 were dipper (22,2%).Obese with BMI zscore &gt;3 was all non dipper (n14 ;100%). In the lean group n 26 was dipper (48.1%),and 28 (51.8%) non dipper. 24 h MAP, Systolic and Diastolic load were significantly higher (p 0,0001) in the obese with BMI z score &gt;3 compared to the lean group.

Conclusion

The statistically significant pathological pattern among obese is the increase inmean PAS and systolic load, as well as the absence of night dipping in severe obese. The increase in systolic load is already evident in obese mild.This gives a significant predictive value of cardiovascular damage to ABPM which increases with the severity of obesity worse.

Ubiquitin binds the amyloid β peptide and interferes with its clearance pathways

Several lines of evidence point to a compromised proteostasis associated with a reduction of the Ubiquitin Proteasome System (UPS) activity in patients affected by Alzheimer's Disease (AD) and suggest that the amyloid β peptide (Aβ) is an important player in the game. Inspired also by many reports, underlining the presence of ubiquitin (Ub) in the amyloid plaques of AD brains, here we set out to test whether Ub may bind the Aβ peptide and have any effect on its clearance pathways. By using an integrated array of MALDI-TOF/UPLC-HRMS, fluorescence, NMR, SPR, Microscale Thermophoresis (MST) and molecular dynamics studies, we consistently demonstrated that Aβ40 binds Ub with a 1 : 1 stoichiometry and K d in the high micromolar range. In particular, we show that the N-terminal domain of the Aβ peptide (through residues D1, E3 and R5) interacts with the C-terminal tail of Ub (involving residues K63 and E64), inducing the central region of Aβ (14HQKLVFFAEDVGSNK28) to adopt a mixed α-helix/β-turn structure. ELISA assays, carried out in neuroblastoma cell lysates, suggest that Aβ competitively binds Ub also in the presence of the entire pool of cytosolic Ub binding proteins. Ub-bound Aβ has a lower tendency to aggregate into amyloid-like fibrils and is more slowly degraded by the Insulin Degrading Enzyme (IDE). Finally, we observe that the water soluble fragment Aβ1-16 significantly inhibits Ub chain growth reactions. These results evidence how the non-covalent interaction between Aβ peptides and Ub may have relevant effects on the regulation of the upstream events of the UPS and pave the way to future in vivo studies addressing the role played by Aβ peptide in the malfunction of proteome maintenance occurring in AD.

Nociceptin reduces the inflammatory immune microenvironment in a conventional murine model of airway hyperresponsiveness

BACKGROUND

Nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) are involved in airway hyperresponsiveness (AHR) and inflammation. However, the role of nociceptin at modulating the inflammatory immune microenvironment in asthma is still unclear.

OBJECTIVE

To understand the role of N/OFQ in the regulation of a Th2-like environment, we used a conventional murine model of AHR.

METHODS

Balb/c and CD1 mice were sensitized to ovalbumin (OVA) and treated with saline solution or N/OFQ, at days 0 and 7. A group of Balb/c mice were killed at 7 and 14 days from the first sensitization for the inflammatory profile evaluation while a group of Balb/c and CD1 mice were aerosol-challenged from day 21 to 23 with OVA and killed 24 h later for functional evaluations.

RESULTS

In OVA-sensitized mice, N/OFQ significantly reduced IL-4+ CD4+ T cells in lymph nodes (LN) and IL-13 in the lungs, while it induced IFN-γ increase in the lung. The efflux of dendritic cells (DCs) to the mediastinic LN and into the lung of OVA-sensitized mice was reduced in N/OFQ-treated and sensitized mice. N/OFQ reduced the expression of CD80 on DCs, indicating its ability to modulate the activation of DCs. In a less prone Th2-like environment mice strain, such as CD1 mice, N/OFQ did not modify lung resistances as observed in BALB/c mice. Finally, spectroscopic data showed the N/OFQ was able to interact onto the membrane of DCs obtained from Balb/c rather than CD1 mice, indicating its ability to modulate AHR in a Th2-like environment with a direct activity on DCs.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data confirmed the capability of N/OFQ to modulate the immune microenvironment in the lung of Th2-biased, OVA-sensitized Balb/c mice, suggesting N/OFQ-NOP axis as a novel pharmacological tool to modulate the inflammatory immune microenvironment in asthma.

The insulin degrading enzyme activates ubiquitin and promotes the formation of K48 and K63 diubiquitin

We report an ATP-dependent ubiquitin conjugation with IDE which, in turn, promotes Ub-Ub linkages in tube tests. We propose a novel function for IDE as a non-canonical ubiquitin activating enzyme.