A critical view on autoantibodies in lupus nephritis: Concrete knowledge based on evidence

Deposition of autoantibodies in glomeruli is a key factor in the development of lupus nephritis (LN). For a long time, anti-dsDNA and anti-C1q antibodies were thought to be the main cause of the kidney damage. However, recent studies have shown that the list of autoantibidies that have renal tropism and deposit in the kidney in LN is increasing and the link between anti-dsDNA and renal pathology is weak due to potential confounders. Aspecific bindings of dsDNA with cationic antibodies and of anti-dsDNA with several renal antigens such as actinin, laminin, entactin, and annexinA2 raised doubts about the specific target of these antibodies in the kidney. Moreover, the isotype of anti-dsDNA in SLE and LN has never received adequate interest until the recent observation that IgG2 are preponderant over IgG1, IgG3 and IgG4. Based on the above background, recent studies investigated the involvement of anti-dsDNA IgG2 and of other antibodies in LN. It was concluded that circulating anti-dsDNA IgG2 levels do not distinguish between LN versus non-renal SLE, and, in patients with LN, their levels do not change over time. Circulating levels of other antibodies such as anti-ENO1 and anti-H2 IgG2 were, instead, higher in LN vs non-renal SLE at the time of diagnosis and decreased following therapies. Finally, new classes of renal antibodies that potentially modify the anti-inflammatory response in the kidney are emerging as new co-actors in the pathogenetic scenario. They have been defined as 'second wave antibodies' for the link with detoxifying mechanisms limiting the oxidative stress in glomeruli that are classically stimulated in a second phase of inflammation. These findings have important clinical implications that may modify the laboratory approach to LN. Serum levels of anti-ENO1 and anti-H2 IgG2 should be measured in the follow up of patients for designing the length of therapies and identify those patients who respond to treatments. Anti-SOD2 could help to monitor and potentiate the anti-inflammatory response in the kidney.

Immunohistochemical Evaluation of Renal Biopsy with Anti-PD1 and p53 to Solve the Dilemma between Platinum- and Pembrolizumab-Induced AKI: Case Report and Review

Introduction: The combination therapy of platinum and pembrolizumab looks like a promising treatment in advanced non-small-cell lung cancer. However, both platinum-based chemotherapy and pembrolizumab can lead to AKI. AKI can occur due to acute tubular necrosis or interstitial nephritis. It is essential to identify the drug responsible for renal damage. For this purpose, we used new immunohistochemistry markers (p53 and anti-PD1 analysis). Case Description: A 77-year-old female patient with advanced non-small-cell lung cancer received the PD-1 inhibitor pembrolizumab and platinum-based chemotherapy carboplatin. The patient, after 60 days, experienced AKI. A kidney biopsy was performed, and two new immunohistochemical techniques for p53 (experimental markers of ATN from platinum) and anti-PDL1 (experimental markers of PD-1 inhibitors nephritis) were employed. Renal biopsies revealed severe tubular damage. No infiltration was detected, and the immunohistochemical assessment of PDL-1 was negative. The expression of p53 was positive. The renal biopsy suggested platinum-induced acute tubular necrosis. After discontinuing steroids and reducing carboplatin, the patient continued with pembrolizumab, and their renal function returned to normal within two months. Discussion: Combining checkpoint inhibitors and platinum-based therapies may result in AKI. The standard method of examining kidney tissue may not provide sufficient information about the effects of these drugs on the kidneys. To address this issue, we recommend incorporating an assessment of the analysis of the expression of PDL1 and p53. This personalized approach will help identify the best treatment option for the patient while ensuring the best possible cancer treatment plan.

Corrigendum: Case report: Multisystem inflammatory syndrome in children with associated proximal tubular injury

[This corrects the article DOI: 10.3389/fneph.2023.1194989.].

MicroRaman spectroscopy detects the presence of microplastics in human urine and kidney tissue

There is a growing concern within the medical community about the potential burden of microplastics on human organs and tissues. In this study, we investigated by microRaman spectroscopy the presence of microplastics in human kidneys and urine. Moreover, an open-access software was developed and validated for the project, which enabled the comparison between the investigated spectra and a self-created spectral database, thus enhancing the ability to characterize polymers and pigments in biological matrices. Healthy portions of ten kidneys obtained from nephrectomies, as well as ten urine samples from healthy donors were analyzed: 26 particles in both kidney and urine samples were identified, with sizes ranging from 3 to 13 μm in urine and from 1 to 29 μm in kidneys. The most frequently determined polymers are polyethylene and polystyrene, while the most common pigments are hematite and Cu-phthalocyanine. This preclinical study proves the presence of microplastics in renal tissues and confirms their presence in urine, providing the first evidence of kidney microplastics deposition in humans.

Microplastics and Kidneys: An Update on the Evidence for Deposition of Plastic Microparticles in Human Organs, Tissues and Fluids and Renal Toxicity Concern

Plastic pollution became a main challenge for human beings as demonstrated by the increasing dispersion of plastic waste into the environment. Microplastics (MPs) have become ubiquitous and humans are exposed daily to inhalation or ingestion of plastic microparticles. Recent studies performed using mainly spectroscopy or spectrometry-based techniques have shown astounding evidence for the presence of MPs in human tissues, organs and fluids. The placenta, meconium, breast milk, lung, intestine, liver, heart and cardiovascular system, blood, urine and cerebrovascular liquid are afflicted by MPs' presence and deposition. On the whole, obtained data underline a great heterogeneity among different tissue and organs of the polymers characterized and the microparticles' dimension, even if most of them seem to be below 50-100 µm. Evidence for the possible contribution of MPs in human diseases is still limited and this field of study in medicine is in an initial state. However, increasing studies on their toxicity in vitro and in vivo suggest worrying effects on human cells mainly mediated by oxidative stress, inflammation and fibrosis. Nephrological studies are insufficient and evidence for the presence of MPs in human kidneys is still lacking, but the little evidence present in the literature has demonstrated histological and functional alteration of kidneys in animal models and cytotoxicity through apoptosis, autophagy, oxidative stress and inflammation in kidney cells. Overall, the manuscript we report in this review recommends urgent further study to analyze potential correlations between kidney disease and MPs' exposure in human.

Vaccines and nephrotic syndrome: efficacy and safety

Vaccines represent the most important medical evolution in the last two centuries allowing prevention and formally eradication of a wide number of infectious diseases. Safety and effectiveness are main issues that still require an open discussion. A few clinical reports described a critical temporal relationship between vaccination and acute nephrotic syndrome, indirectly suggesting an association. For this review, the literature was reviewed to identify articles reporting associations of nephrotic syndrome with vaccines against a vast array of infectious diseases (including bacteria, virus and Sars-Cov-2). As specific aims, we evaluated effectiveness and safety in terms of occurrence of either "de novo" nephrotic syndrome in health subjects or "relapse" in those already affected by the disease. In total, 377 articles were found; 166 duplicates and 71 non-full text, animal studies or non-English language were removed. After excluding another 50 articles not containing relevant data on generic side effects or on relapses or new onset nephrotic syndrome, 90 articles met the search criteria. Overall, studies reported the effect of vaccines in 1015 patients, plus 4 nationwide epidemiologic investigations. Limited experience on vaccination of NS patients with measles, mumps, and rubella live attenuated vaccines does not allow any definitive conclusion on their safeness. VZV has been administered more frequently without side effects. Vaccines utilizing virus inactivated, recombinant, and toxoid can be utilized without risks in NS. Vaccines for influenza reduce the risk of infections during the pandemic and are associated with reduced risk of relapse of NS typically induced by the infection. Vaccines for SARS-CoV-2 (all kinds) offer a concrete approach to reduce the pandemic. "De novo" NS or recurrence are very rare and respond to common therapies.

Biologics in steroid resistant nephrotic syndrome in childhood: review and new hypothesis-driven treatment

Nephrotic syndrome affects about 2-7 per 100,000 children yearly and accounts for less than 15% of end stage kidney disease. Steroids still represent the cornerstone of therapy achieving remission in 75-90% of the cases The remaining part result as steroid resistant nephrotic syndrome, characterized by the elevated risk of developing end stage kidney disease and frequently presenting disease recurrence in case of kidney transplant. The pathogenesis of nephrotic syndrome is still far to be elucidated, however, efficacy of immune treatments provided the basis to suggest the involvement of the immune system in the pathogenesis of the disease. Based on these substrates, more immune drugs, further than steroids, were administered in steroid resistant nephrotic syndrome, such as antiproliferative and alkylating agents or calcineurin inhibitors. However, such treatments failed in inducing a sustained remission. In last two decades, the developments of monoclonal antibodies, including the anti-CD20 rituximab and inhibitor of B7-1 abatacept, represented a valid opportunity of treatment. However, also the effectiveness of biologics resulted limited. We here propose a new hypothesis-driven treatment based on the combining administration of rituximab with the anti-CD38 monoclonal antibody daratumumab (NCT05704400), sustained by the hypothesis to target the entire B-cells subtypes pool, including the long-lived plasmacells.

Case Report: Multisystem inflammatory syndrome in children with associated proximal tubular injury

Introduction

SARS-CoV-2 infection in the pediatric population can be associated with a multiorgan inflammatory syndrome called children's multisystem inflammatory syndrome (MIS-C). The kidneys can be affected by a broad spectrum of possible injuries, whose pathogenetic mechanisms are still unclear.Case report: We report the case of a 5-year-old boy with severe cardiac involvement in the context of MIS-C. After two weeks of hospitalization, an abdominal ultrasound showed massive bladder "debris", followed by the onset of normoglycemic glycosuria. Over time, there was a progressive increase in glycosuria, and the presence of a mat of amorphous phosphate crystals was evidenced on urinary sediment. Together with the findings of hypo-uricemia, increased urinary uric acid, and globally increased urinary amino acids, a clinical picture of kidney proximal tubular damage with secondary Fanconi-like syndrome took shape.

Discussion

This case report describes the case of a patient with MIS-C with cardiac and kidney involvement characterized by proximal tubular damage, which slowly improved but still persisted at the 8-month follow-up. The pathogenesis of the damage is unclear and probably multifactorial.

Co-Occurrence of Nephronophthisis Type 1 and Alström Syndrome: A Case Report

We describe the unique case of a patient in whom two ciliopathies with autosomal recessive transmission were clinically and molecularly diagnosed: nephronophthisis type 1 (NPHP1) and Alström syndrome (AS). NPHP1 is one of the main genetic causes of terminal kidney failure in childhood. AS is an ultra-rare multi-systemic disease, characterized by progressive kidney disease, hepatic failure, dystrophy of the rods and cones to blindness, slowly progressive neuro-sensory deafness, dilated cardiomyopathy, obesity, insulin resistance/type 2 diabetes mellitus. The coexistence in the same patient of two rare syndromes with overlapping clinical manifestations but genetically different is an eventuality to be considered. This case report would describe the onset and progression of the multi-organ manifestations of both syndromes to highlight that ciliopathies present a strong phenotype overlap but also specific peculiarities. Therefore, to make a correct diagnosis that is essential to achieve the best clinical management could be challenging.

Multicentric Carpotarsal Osteolysis Syndrome Associated Nephropathy: Novel Variants of MAFB Gene and Literature Review

Multicentric carpo-tarsal osteolysis (MCTO) is a rare osteolysis syndrome mainly involving carpal and tarsal bones usually presenting in early childhood. MCTO has autosomal dominant inheritance with heterozygous mutation in the MAFB gene. The skeletal disorder is often associated with chronic kidney disease. Data on clinical characterization and best treatment option of MCTO-associated nephropathy are scarce and mostly limited to case reports. With the aim to better define the phenotype and long-term outcomes of MCTO-associated nephropathy, we launched an online survey through the Workgroup for hereditary glomerulopathies of the European Rare Kidney Disease Network (ERKNet). Overall, we collected clinical and genetic data of 54 MCTO patients, of which 42 previously described and 12 new patients. We observed a high rate of kidney involvement (70%), early age of kidney disease onset, nephrotic-range proteinuria, and a kidney survival around of 40% at long-term follow-up. Our finding confirmed the heterogeneity of clinical manifestations and widen the spectrum of phenotypes resulting from MCTO-associated nephropathy. Furthermore, we report the first case of complete remission after treatment with cyclosporine A. We demonstrated that multidisciplinary care is essential for MCTO patients and early referral to nephrologists is therefore warranted to facilitate prompt treatment.

LGG-34. Nephrological impact of BRAF inhibitors in a pediatric population of central nervous system tumors: a single institution experience

BRAF inhibitors (iBRAF) are under investigations in ongoing clinical trials for pediatric brain tumor treatment. Preliminary data regarding the pediatric population report pyrexia, hematological, dermatological, cardiac, and ophthalmic toxicities among the most common adverse events. Acute kidney injury (AKI), mainly due to tubular interstitial injury, has been reported in the adult population. With our study we want to contribute to a more comprehensive knowledge of the short- and long-term nephrological adverse effects of iBRAF in a pediatric population. We collected and reviewed clinical and laboratory data of all patients treated with iBRAF for pediatric central nervous system tumors at our Institution and available for publication. AKI was monitored through serial creatinine measurements, kidney function with estimated glomerular filtration rate (eGFR) and kidney injury with creatinuria/proteinuria ratio. Tubular injury was evaluated with fractional excretion of sodium, potassium and magnesium and with glycosuria. Moreover, urine was examined to detect presence and morphology of erythrocytes. Eight patients were identified, 3 females; median age at treatment start was 9 years (range 2,75 – 18,75). Six patients with BRAFV600E–mutated pediatric Low-Grade Glioma were treated with Vemurafenib, 1 patient with BRAFV600E-mutated pediatric High-Grade Glioma was treated with Vemurafenib and 1 patient with BRAFV600E-mutated Langerhans Cell Histiocytoses was treated with Dabrafenib. Seven patients were considered for analysis. After a median follow up of 3,83 years (range 2,25 – 6,58) no AKI was reported and all patients but two retained normal eGFR at last follow up. No tubular and glomerular injury laboratory findings were detected, and erythrocytes in the urine resulted always below the upper limit of normality. CONCLUSIONS: iBRAF were not associated with AKI and tubular injury. Nevertheless, some data, namely significative decrease of eGFR in two out of seven patients, warrants further investigations.

The role of kidney dysfunction in COVID-19 and the influence of age

COVID-19 is strongly influenced by age and comorbidities. Acute kidney injury (AKI) is a frequent finding in COVID-19 patients and seems to be associated to mortality and severity. On the other hand, the role of kidney dysfunction in COVID-19 is still debated. We performed a retrospective study in a cohort of 174 hospitalized COVID-19 patients in Italy from March 3rd to May 21st 2020, to investigate the role of kidney dysfunction on COVID-19 severity and mortality. Moreover, we examined in depth the relationship between kidney function, age, and progression of COVID-19, also using different equations to estimate the glomerular filtration rate (GFR). We performed logistic regressions, while a predictive analysis was made through a machine learning approach. AKI and death occurred respectively in 10.2% and 19.5%, in our population. The major risk factors for mortality in our cohort were age [adjusted HR, 6.2; 95% confidence interval (CI) 1.8-21.4] and AKI [3.36 (1.44-7.87)], while, in these relationships, GFR at baseline mitigated the role of age. The occurrence of AKI was influenced by baseline kidney function, D-dimer, procalcitonin and hypertension. Our predictive analysis for AKI and mortality reached an accuracy of ≥ 94% and ≥ 91%, respectively. Our study scales down the role of kidney function impairment on hospital admission , especially in elderly patients. BIS-1 formula demonstrated a worse performance to predict the outcomes in COVID-19 patients when compared with MDRD and CKD-EPI.

MO1033: Kidney and Bone Marrow Involvement in Ipex Syndrome with Atypical Presentation: the ‘Fil Rouge’ of Treg Between Ipex Features and Other Clinical Entities

BACKGROUND AND AIMS

The transcription factor Forkhead box protein P3 (FOXP3) is central to the function of regulatory T cells (Treg). Mutations in the FOXP3 gene lead to a systemic disease called immune dysregulation, polyendocrinopathy and enteropathy, X-linked syndrome (IPEX). Some FOXP3 mutations were associated with atypical presentation including rare diseases such as IgG4 related disease (IgG4 RD) and autoimmune lymphoproliferative syndrome (ALPS). IgG4 RD is characterized by fibro-inflammatory tissue damage and often by elevated serum IgG4, whereas ALPS is presented by early-onset, chronic, nonmalignant lymphoproliferation, splenomegaly and autoimmune manifestations due to defective lymphocyte apoptosis, due mainly to mutation of genes involved in the apoptosis pathway. Kidney involvement in ALPS is uncommon, whereas in IPEX and IgG4 RD is more frequent, with different renal manifestations.

METHOD

We reported two atypical cases of IPEX characterized by the kidney and haematologic involvement. These cases are anecdotal for the wide spectrum of possible phenotypes associated with FOXP3 mutations.

RESULTS

Case 1. A 16-year male with clinical diagnosis of ALPS was treated with an mTOR inhibitor. Due to the onset of proteinuria until 650 mg/day and estimated glomerular filtration rate (eGFR) 66 mL/min, a kidney biopsy was performed and light microscopy showed a membranous pattern. The M-type phospholipase A2 receptor (PLA2R) on serum was negative as well as immunofluorescence (IF) on tissue. IgG-IgG4 immunohistochemical (IHC) staining was negative. We decided to re-evaluate the genetics of the patient, implementing the HPO (Human Phenotype Ontology) code. We found a mutation of the FOXP3 gene (NM_014009.3): c.779T > A (p.L260Q), never reported before on the GnomAD database and predicted to be ‘Likely Pathogenic’ by the suite of variant annotation. The patient does not present the classical triad of IPEX and Treg resulted normal. He was treated with steroids and continues mTOR inhibitor with good control of proteinuria and stable kidney function. Case 2. A 2-year boy was diagnosed with a trilinear bone marrow failure, genetic investigations were negative. He presented elevated serum levels of IgG4 subclass and kidney failure with tubular acidosis. A renal biopsy showed MGP associated with TIN. IF and IHC for PLA2R resulted positive. IHC staining for IgG4 showed overlapping positivity for IgG and IgG4. After the diagnosis of IgG4 RD, steroid therapy was started, without clinical response. Thereafter the patient underwent a bone marrow transplant from his brother (HLA-identical). In consideration of the rarity of IgG4 RD in children, we decided to perform a new genetic exam. A whole-exome sequencing on the proband and relatives was done. A hemizygous mutation of the FOXP3 gene (NM_014009.3), c.1087A > G (p.I363V), was found. This variant, inherited by the mother and found also in the proband's brother, was already described in the literature, thus a diagnosis of IPEX was done. Therefore, Treg resulted normal for brother and mother but not in our patient (0.3%). The patient underwent kidney transplantation, and after 1 year he presents normal kidney function.

CONCLUSION

MGP and IgG4 RD are rare in paediatrics, and they encouraged us to perform further investigations and reconsider the previous diagnosis. MGP pathogenesis in IPEX is consistent with recent evidence of unbalance of Th17/Treg in idiopathic MGP, with a significant reduction of Treg cell and FOXP3 expression. Th17/Treg may be implicated also in the pathogenesis of IgG4 RD as sources of cytokines production responsible for fibrosis and IgG4-producing B cells. FOXP3 + Treg and FAS-ligand are crucial for autoimmunity and self-tolerance. In ALPS patients a reduced expression of FOXP3 + Treg subsets but with the normal suppressive function was found. IPEX poses a diagnostic challenge considering the spectrum of different phenotypes, but to recognize kidney involvement, together with the growing use of wide genomic analysis, could play a central role.

Case Report: Atypical Manifestations Associated With FOXP3 Mutations. The “Fil Rouge” of Treg Between IPEX Features and Other Clinical Entities?

Introduction

The Forkhead box protein P3 (FOXP3) is a transcription factor central to the function of regulatory T cells (Treg). Mutations in the FOXP3 gene lead to a systemic disease called immune dysregulation, polyendocrinopathy, and enteropathy, an X-linked syndrome (IPEX) characterized by the triad of early-onset intractable diarrhea, type 1 diabetes, and eczema. An atypical presentation of IPEX has been reported.

Method

We report rare cases with equivocal clinical associations that included inflammatory, kidney, and hematologic involvements screened with massively parallel sequencing techniques.

Results

Two patients with hemizygous mutations of FOXP3 [c.779T>A (p.L260Q)] and [c.1087A>G (p.I363V)] presented clinical manifestations not included in typical cases of IPEX: one was a 16-year-old male patient with an initial clinical diagnosis of autoimmune lymphoproliferative syndrome (ALPS) and who developed proteinuria and decreased kidney function due to membranous nephropathy, an autoimmune renal condition characterized by glomerular sub-epithelial antibodies. The second patient was a 2-year-old child with bone marrow failure who developed the same glomerular lesions of membranous nephropathy and received a bone marrow transplantation. High levels of IgG4 in serum, bone marrow, and kidney led to the definition of IgG4-related kidney disease (IgG4 RKD) in this young boy. The circulating Treg levels were normal in the former case and very low in the second.

Conclusion

Two atypical associations of functional mutations of FOXP3 that include ALPS and IgG4 RKD are described. Membranous nephropathy leading to renal failure completed in both cases the clinical phenotypes that should be included in the clinical panorama of FOXP3 failure.

The Ketogenic Diet: Is It an Answer for Sarcopenic Obesity?

This review aims to define the effectiveness of the ketogenic diet (KD) for the management of sarcopenic obesity. As the combination of sarcopenia and obesity appears to have multiple negative metabolic effects, this narrative review discusses the effects of the ketogenic diet as a possible synergic intervention to decrease visceral adipose tissue (VAT) and fatty infiltration of the liver as well as modulate and improve the gut microbiota, inflammation and body composition. The results of this review support the evidence that the KD improves metabolic health and expands adipose tissue γδ T cells that are important for glycaemia control during obesity. The KD is also a therapeutic option for individuals with sarcopenic obesity due to its positive effect on VAT, adipose tissue, cytokines such as blood biochemistry, gut microbiota, and body composition. However, the long-term effect of a KD on these outcomes requires further investigations before general recommendations can be made.

FC 101PROTEOMIC PROFILE OF MESOTHELIAL EXOSOMES ISOLATED FROM PERITONEAL DIALYSIS EFFLUENT OF CHILDREN WITH FOCAL SEGMENTAL GLOMERULOSCLEROSIS

Background and Aims

Peritoneal dialysis (PD) is the worldwide preferred dialysis treatment for children affected by end stage kidney disease. However, due to the unphysiological composition of PD fluids, the peritoneal mesothelium of these patients may undergo structural and functional alterations, which may cause fibrosis. Several factors may accelerate this process and primary kidney disease may have a causative role. In particular, patients affected by corticosteroid resistant focal segmental glomerulosclerosis (FSGS), a rare glomerular disease leading to nephrotic syndrome, seems more prone to develop peritoneal fibrosis. The mechanism causing this predisposition is still unrecognized. To better define this condition, we carried out, for the first time, a new comprehensive comparative proteomic mass spectrometry analysis of mesothelial exosomes from peritoneal dialysis effluent (PDE).

Method

We enrolled 12 paediatric patients on PD. Half of them affected by FSGS and the others affected by other disorders (NO FSGS). Exosomes from mesothelial peritoneal cells were isolated by centrifugation and, using a biotinylated antibody and streptavidin magnetic beads. Exosome size was determined by dynamic light scattering, and antigen profile of exosomes was assayed by western blot. Mass spectrometry data were analyzed by unsupervised hierarchical clustering using multidimensional scaling, in order to identify outliers and dissimilarity between samples. The normalized data were used to construct a co-expression network using the weighted gene co-expression network analysis (WGCNA). A weighted adjacency matrix was constructed, and transformed into a topological overlap matrix, which measures the network connectivity of all proteins. To identify the relationship between each module and each clinical trait, we used module eigengenes (MEs) and calculated the correlation between MEs and the clinical traits. To identify the hub proteins of modules that maximize the discrimination between FSGS and NO FSGS samples, we applied T-test, and non-linear support vector machine (SVM) learning. Finally, gene set enrichment analysis was done to build a functional proteins network based on their Gene Ontology (GO) annotations extracted from the Gene Ontology Consortium.

Results

Our omic study demonstrated that SVM allowed a complete distinction of the whole proteomic exosome mesothelial content of FSGS versus NO FSGS (100% accuracy). Out of the 2490 identified proteins, 40% (995) were involved in endothelial to mesenchymal transition /fibrosis and in the TGF-B pathway. The WGCNA analysis highlighted a total of 40 proteins were that maximize the discrimination between FSGS and NO FSGS patients (Figure 1A). Their expression profile is reported in a heatmap diagram (Figure 1B).

Additionally, we performed GO enrichment analysis (Figure 2) and the algorithm identified that some of the discriminative proteins (TIMP1, CTHRC1, SPARC, CHMP4B, COL5A2, ANXA13, FNC2 and CENP-E) were also highly correlated to the peritoneal dialysis vintage, fibrosis, EMT and PM disease.

Conclusion

Our data demonstrated, for the first time, that mesothelial cells of FSGS are more prone to activate a pro-fibrotic machinery with exosomes having a primary role in this process. Moreover, they indicated that identified FSGS-associated element in mesothelial exosome protein could be employed as potential new biomarkers of mesothelial integrity. Finally, results highlighted that FSGS should be treated with more biocompatible dialysis solution, reduce the length of time on PD and personalize type and regimens of PD to minimize the risk of rapid loss of peritoneal membrane.

Renal dysfunction in cardiovascular diseases and its consequences

It is well known that the heart and kidney and their synergy is essential for hemodynamic homeostasis. Since the early XIX century it has been recognized that cardiovascular and renal diseases frequently coexist. In the nephrological field, while it is well accepted that renal diseases favor the occurrence of cardiovascular diseases, it is not always realized that cardiovascular diseases induce or aggravate renal dysfunctions, in this way further deteriorating cardiac function and creating a vicious circle. In the same clinical field, the role of venous congestion in the pathogenesis of renal dysfunction is at times overlooked. This review carefully quantifies the prevalence of chronic and acute kidney abnormalities in cardiovascular diseases, mainly heart failure, regardless of ejection fraction, and the consequences of renal abnormalities on both organs, making cardiovascular diseases a major risk factor for kidney diseases. In addition, with regard to pathophysiological aspects, we attempt to substantiate the major role of fluid overload and venous congestion, including renal venous hypertension, in the pathogenesis of acute and chronic renal dysfunction occurring in heart failure. Furthermore, we describe therapeutic principles to counteract the major pathophysiological abnormalities in heart failure complicated by renal dysfunction. Finally, we underline that the mild transient worsening of renal function after decongestive therapy is not usually associated with adverse prognosis. Accordingly, the coexistence of cardiovascular and renal diseases inevitably means mediating between preserving renal function and improving cardiac activity to reach a better outcome.

Returning to dialysis after kidney allograft failure: the experience of the Italian Registry of Paediatric Chronic Dialysis

BACKGROUND

The need for dialysis after kidney allograft failure (DAGF) is among the top five reasons for dialysis initiation, making this an important topic in clinical nephrology. However, data are scarce on dialysis choice after transplantation and clinical outcomes for DAGF in children.

METHODS

Patients receiving chronic dialysis < 18 years were recorded from January 1991 to January 2019 by the Italian Registry of Pediatric Chronic Dialysis (IRPCD). We investigated factors influencing choice of dialysis modality, patient outcome in terms of mortality, switching dialysis modality, and kidney transplantation.

RESULTS

Among 118 patients receiving DAGF, 41 (35%) were treated with peritoneal dialysis (PD), and 77 (65%) with haemodialysis (HD). Significant predictors for treatment with PD were younger age at dialysis start (OR 0.85 per year increase [95%CI 0.72-1.00]) and PD use before kidney transplantation (OR 8.20 [95%CI 1.82-37.01]). Patients entering DAGF in more recent eras (OR 0.87 per year increase [95%CI 0.80-0.94]) and with more than one dialysis modality before kidney transplantation (OR 0.56 for being treated with PD [0.12-2.59]) were more likely to be initiated on HD. As compared to patients on HD, those treated with PD exhibited increased but non-significant mortality risk (HR 2.15 [95%CI 0.54-8.6]; p = 0.28) and higher prevalence of dialysis-related complications during DAGF (p = 0.002) CONCLUSIONS: Patients entering DAGF in more recent years are more likely to be initiated on HD. In this specific population of children, use of PD seems associated with a more complicated course. A higher resolution version of the Graphical abstract is available as Supplementary information.

Volume Balance in Chronic Kidney Disease: Evaluation Methodologies and Innovation Opportunities

BACKGROUND

Patients affected by chronic kidney disease are at a risk of cardiovascular morbidity and mortality. Body fluids unbalance is one of the main characteristics of this condition, as fluid overload is highly prevalent in patients affected by the cardiorenal syndrome.

SUMMARY

We describe the state of the art and new insights into body volume evaluation. The mechanisms behind fluid balance are often complex, mainly because of the interplay of multiple regulatory systems. Consequently, its management may be challenging in clinical practice and even more so out-of-hospital. Availability of novel technologies offer new opportunities to improve the quality of care and patients' outcome. Development and validation of new technologies could provide new tools to reduce costs for the healthcare system, promote personalized medicine, and boost home care. Due to the current COVID-19 pandemic, a proper monitoring of chronic patients suffering from fluid unbalances is extremely relevant. Key Message: We discuss the main mechanisms responsible for fluid overload in different clinical contexts, including hemodialysis, peritoneal dialysis, and heart failure, emphasizing the potential impact provided by the implementation of the new technologies.

Myostatin in the Arterial Wall of Patients with End-Stage Renal Disease

AIM

Myostatin (Mstn) has been described as a trigger for the progression of atherosclerosis. In this study, we evaluated the role of Mstn in arterial remodeling in patients with end-stage renal disease (ESRD).

METHODS

Vascular specimens were collected from 16 ESRD patients (56.4±7.9 years) undergoing renal transplant (recipients) and 15 deceased kidney non-uremic donors (55.4±12.1 years). We studied gene and protein expression of Mstn, ubiquitin ligases, Atrogin-1, and muscle ring finger protein-1 (MuRF-1), inflammatory marker CCL2, cytoskeleton components, and Klotho by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Moreover, we assessed vascular calcification and collagen deposition. Finally, we studied the effects of recombinant Mstn on rat vascular smooth muscle cells (VSMCs, A7r5) and evaluated the effects of uremic serum (US) on primary human VSMCs.

RESULTS

Myostatin mRNA was upregulated in the arterial vascular wall of recipients compared with donors (~15- folds, p＜0.05). This response was accompanied by the upregulation of gene expression of Atrogin-1 and MuRF-1 (＋2.5- and ＋10-fold) and CCL2 (＋3-fold). Conversely, we found downregulation of protein expression of Smoothelin, α-smooth muscle actin (α-SMA), vimentin, and Klotho (-85%, -50%, -70%, and -80%, respectively; p＜0.05) and gene expression of vimentin and Klotho. Exposition of A7r5 to Mstn induced a time-dependent SMAD 2/SMAD 3 phosphorylation and expression of collagen-1 and transforming growth factor β (TGFβ) mRNA, while US induced overexpression of Mstn and Atrogin-1 and downregulation of Smoothelin and Klotho.

CONCLUSIONS

Our data suggest that uremia might induce vascular Mstn gene expression together with a complex pathway of molecular and structural changes in the vascular wall. Myostatin, in turn, can translate the metabolic alterations of uremia into profibrotic and stiffness inducing signals.

P1832IGG4 RELATED DISEASE: NEPHROPATHY AND BONE MARROW FAILURE IN A 2 YEAR-OLD CHILD

Background and Aims

IgG4 related disease (IgG4 RD) is a recently recognized systemic immune-mediated disorder. Pathophysiology of the disease is still unclear. It is characterized by fibro-inflammatory damage of the tissues, IgG-4 positive plasma-cells and often by elevated serum IgG4. This systemic disease can potentially affect every organ. Renal involvement can include tubulo-interstitial nephritis (TIN), membranous glomerulopathy (MGP) and retroperitoneal fibrosis.

The epidemiology is still poorly described, but the disease seems more frequent in men over 50 years of age. Only few cases of IgG4 RD are reported in pediatric patients.

Method

We describe the first case of IgG4 related kidney disease (IgG4 RKD) in a child with concomitant bone marrow failure.

Results

M.C., a 2 year-old child, was diagnosed in 2017 with a trilinear bone marrow failure (HB 7.2 g/dL; PLT 6.000/mmc; PMC 923/mmc). Bone marrow biopsy showed poor and dyshomogeneous cellularity (20%) and lymphoplasmacytic infiltrate organized in two follicular structures. All investigations performed to rule out inherited bone marrow failure were negative (DEB test, telomere lenght measurement, c-Mpl mutation analysis, mithocondrial DNA analysis)

IgG subclass analysis showed elevated serum levels of IgG4 subclass (353 mg/dL- normal level &lt; 120 mg/dL).

During the hospitalization, kidney failure with tubular acidosis was also found (creatinine 1.3 mg/dL, eGFR 28.5 mL/min/1.73 mq, bicarbonate 8.3 mEq/L). Urine analysis showed microematuria, proteinuria (1.07 g/L) and granular casts. Renal ultrasound did not demonstrate abnormal findings.

A renal biopsy was performed and a kidney sample with up to 40 glomeruli was obtained. Light microscopy (H&E, JSM, PAS and Masson’s trichrome stains) showed tubule-interstitial inflammatory infiltrate (mainly composed of lymphoplasmacytic cells), irregular thickening of the glomerular basement membranes. IHC stains for C4D showed subepithelial deposits (++).

IF was negative for IgA, IgM, C4 and C1q while showed subepithelial glomerular membrane IgG deposits (+++) with granular pattern and tubular wall deposits; glomerular deposits (+) and focal tubular deposits (+++) of C3.

A diagnosis of MGP associated with TIN was made. IHC staining for IgG4 was also performed, which demonstrated plasmacells with overlapping positivity for IgG and IgG4.

After the diagnosis of IgG4 RKD, an immune-suppressive therapy with steroids (1 mg/kg/die)– targeting both the haematological disorder and glomerulopathy - was started, without clinical response. Thereafter the patient underwent bone marrow transplant from HLA-identical family donor.

Conclusion

GMP indeed is a very uncommon disease in childhood. Moreover, the association of GMP with TIN is reported in few cases in the literature. Only in the last decade some case of TIN and GMP have been recognized as IgG4 RD and few cases have been reported in adults of IgG4 RKD with simultaneous TIN and GMP. To exclude primary GMP we will perform also the research of antiPLA2r1 antibodies in kidney biopsy. However, the specificity of antiPLA2r in children is lower than in adults and the association of primary GMP with IgG4 TIN is unlikely. IgG4 RD is an emerging systemic disease and it should be taken into account in differential diagnosis in systemic auto-immune diseases, also in the pediatric age. IgG4 RKD and bone marrow failure IgG4 RD are very rare in children but its real incidence among pediatric patients could be still underestimated.

P1804DIALYSIS AFTERKIDNEY GRAFT LOST: DATA OF THE ITALIAN REGISTRY OF PEDIATRIC DIALYSIS

Background and Aims

An increasing number of patients are returning to dialysis after kidney allograft failure (KAF). These patients are at higher risk of complications and mortality compared with incident ESKD patients.. In the pediatric population these data are missing and outcomes have never been investigated before in a nationally representative sample. The aim of this study was to describe the characteristics and hard outcomes of children entering dialysis after KAF in a large population of pediatric dialysis patients.

Method

We retrospectively reviewed the files of patients receiving chronic dialysis at &lt;18 years, recorded from January 1990 to June 2019 by the Italian Registry of Pediatric Chronic Dialysis (IRPCD), a nationwide population-based chronic dialysis network involving all 12 Italian pediatric dialysis centers. We identified 126 patients who had returned to dialysis after KAF. All patients were followed from (re)initiation of dialysis until death, re-transplantation or loss to follow-up. Multivariable regression and survival analysis were used to evaluate factors involved in the choice of dialysis modality and patient outcomes.

Results

After KAF, 45 (35.7 %) patients were treated with PD and 81 (64,3%) with HD. Prior to kidney transplantation (Ktx), 74 (58.7%) were on PD, 45 (35.7%) on HD, and 7 on conservative care (5.5%). Compared with PD patients, those on HD were older (median age of 14.8 years [IQR 11.4-17.5] vs. 10.8 [IQR 2-6.5] vs.; p=0.002), had a longer transplant vintage ([55.2 months [13.2-100.3]) vs. 33 [5.1-82.2], and reentered dialysis in more recent calendar years (2013 [2007-2017] vs. 2004 [2001-2009]). Significant predictors for being treated with PD after KAF were a younger age at dialysis start (OR 0.83 per year increase [95%CI 0.72-0.94]) and a history of PD use before Ktx (OR 12.74 [2.2-74.6]). Patients returning to dialysis in more recent eras (OR 0.87 per year increase [0.81-0.94]) and those who were treated with more than one dialysis modality before Ktx (OR 0.15 for being treated with PD [0.04-0.63]) were more likely to be initiated on HD.

Over the observation period, 6 PD (13.6%) and 3 HD (4.2%) patients died. After adjustment for several covariates, patients on PD exhibited an increased risk for mortality compared with HD (HR 4.65 [1.12-19.30], while the difference for modality failure and access to renal transplantation did not reach statistical significance (Fig.1)

Conclusion

Patients returning to dialysis after KAF in more recent years are more likely to be initiated on HD rather than PD. According to our registry data, the use of PD is associated with a lower survival among patients initiating dialysis after KAF.

Fig.1 Cumulative incidences for the competing events, death, transplant and other techniques (solid line: PD, dash line: HD)

Significance of serum Myostatin in hemodialysis patients

BACKGROUND

Malnutrition and muscle wasting are common in haemodialysis (HD) patients. Their pathogenesis is complex and involves many molecules including Myostatin (Mstn), which acts as a negative regulator of skeletal muscle. The characterisation of Mstn as a biomarker of malnutrition could be useful in the prevention and management of this condition. Previous studies have reported no conclusive results on the actual relationship between serum Mstn and wasting and malnutrition. So, in this study, we evaluated Mstn profile in a cohort of regular HD patients.

METHODS

We performed a cross-sectional study, enrolling 37 patients undergoing bicarbonate-HD (BHD) or haemodiafiltration (HDF) at least for six months. 20 sex-matched healthy subjects comprised the control group. Mstn serum levels were evaluated by ELISA before and after HD. We collected clinical and biochemical data, evaluated insulin resistance, body composition, malnutrition [by Malnutrition Inflammation Score (MIS)] and tested muscle function (by hand-grip strength, six-minute walking test and a questionnaire on fatigue).

RESULTS

Mstn levels were not significantly different between HD patients and controls (4.7 ± 2.8 vs 4.5 ± 1.3 ng/ml). In addition, while a decrease in Mstn was observed after HD treatment, there were no differences between BHD and HDF. In whole group of HD patients Mstn was positively correlated with muscle mass (r = 0.82, p < 0.001) and inversely correlated with age (r = - 0.63, p < 0.01) and MIS (r = - 0.39, p = 0.01). No correlations were found between Mstn and insulin resistance, such as between Mstn levels and parameters of muscle strength and fatigue. In multivariate analysis, Mstn resulted inversely correlated with fat body content (β = - 1.055, p = 0.002).

CONCLUSIONS

Circulating Mstn is related to muscle mass and nutritional status in HD patients, suggesting that it may have a role in the regulation of skeletal muscle and metabolic processes. However, also considering the lack of difference of serum Mstn between healthy controls and HD patients and the absence of correlations with muscle function tests, our findings do not support the use of circulating Mstn as a biomarker of muscle wasting and malnutrition in HD.

Soluble Toll-like Receptor 4: A New Player in Subclinical Inflammation and Malnutrition in Hemodialysis Patients

OBJECTIVE

Toll-like receptor 4 (TLR4) promotes inflammation in hemodialysis patients (HD). A soluble form of extracellular TLR4 (sTLR4) has been recently characterized, which showed the ability to attenuate TLR4 signalling. In this study, we describe the sTLR4 profile in regular HD patients.

SUBJECTS

In a cross-sectional study we enrolled forty prevalent HD patients (68.2 ± 16.3 years, twenty-five males) with a median dialysis vintage of 41 months. Nineteen patients were undergoing standard bicarbonate HD (BHD) and 21 patients on-line hemodiafiltration (HDF). Ten healthy sex-matched subjects constituted the controls (C).

INTERVENTION

Before and after the HD session, serum was tested for sTLR4 levels by ELISA. Moreover, clinical and biochemical data were collected, including body mass index, albumin, and C-reactive protein (CRP) levels. Body composition was expressed as a 3-compartment model, providing lean tissue index and fat tissue index (FTI).

MAIN OUTCOME MEASURE

Describe the profile of sTLR4 in HD patients, evaluating the correlations among sTLR4 levels and the main clinical characteristics, inflammatory and nutritional parameters.

RESULTS

Patients with subclinical inflammation (i.e., high CRP levels without clinical symptomatology) presented higher sTLR4 levels (0.42 ± 0.25 ng/mL) with respect to both C and not inflamed HD patients (0.23 ± 0.19 ng/mL, P < .05). There was a significant direct correlation between predialysis sTLR4 and body mass index, FTI (r = 0.55), and CRP levels (r = 0.52) and inverse correlation with lean tissue index and albumin (r = -0.4). In multivariate analysis, sTLR4 resulted directly associated with FTI (P = .038). Notably, sTLR4 levels resulted higher in bicarbonate hemodialysis versus hemodiafiltration (0.37 ± 0.18 vs. 0.19 ± 0.21 ng/mL, P < .05).

CONCLUSIONS

sTLR4 correlates with inflammatory and nutritional parameters, presenting as a new potential player in modulating subclinical inflammation in HD patients.

[Donor and recipient selection in living donor kidney transplantation: eligibility]

This review is intended to be a guide for the physician to evaluate and prepare a donor / recipient couple for living kidney transplantation. Although it is intended to be exhaustive, it will not be able to respond at all possible and different cases, but it may apply at most of them. Renal transplantation is considered the choice treatment for patients with chronic renal failure and if the kidney transplant is performed pre-emptive it is associated with better organ and patient survival. The main aim of the program is to evaluate the risks of donor and recipient and to ensure the donor safety and well-being. Eligibility for living transplant can only be granted when the risks are acceptable, well defined and the couple is adequately informed. The review includes clinical and legal procedures needed to transplantation. Early conditions that contraindicate the transplant must be removed, to avoid unnecessary exams, excessive waste of time, money. The sequence of the exams has been ordered so that costly and invasive surveys are carried out only after other simple and essential investigations have confirmed the transplant suitability. Special attention should be paid to the renal function measurement, proteinuria, hematuria, hypertension, obesity, pre diabetes, renal calculus, and cancers. To give eligibility for living transplant is often not easy, but a careful study can avoid many complications and improve the transplant outcome.

Severe cyclophosphamide-related hyponatremia in a patient with acute glomerulonephritis

Cyclophosphamide is frequently used to treat cancer, autoimmune and renal diseases, such as rapidly progressive glomerulonephritis. Its side effects are well-known, including bone marrow depression, infections, alopecia, sterility, bladder malignancy and hemorrhagic cystitis. Moreover, in some cases cyclophosphamide use has been related to the onset of hyponatremia, by development of a syndrome of inappropriate antidiuresis. Indeed, severe hyponatremia has been previously reported in patients treated with high-dose or moderate-dose of intravenous cyclophosphamide, while only few cases have been reported in patients treated with low dose. Here, we discuss a case of a syndrome of inappropriate antidiuresis followed to a single low-dose of intravenous cyclophosphamide in a patient with a histological diagnosis of acute glomerulonephritis, presenting as acute kidney injury. After cyclophosphamide administration (500 mg IV), while renal function gradually improved, the patient developed confusion and headache. Laboratory examinations showed serum sodium concentration dropped to 122 mmol per liter associated with an elevated urinary osmolality of 199 mOsm/kg, while common causes of acute hyponatremia were excluded. He was successfully treated with water restriction and hypertonic saline solution infusion with the resolution of the electrolyte disorder. This case, together with the previous ones already reported, highlights that electrolyte profile should be strictly monitored in patients undergoing cyclophosphamide therapy in order to early recognize the potentially life-threatening complications of acute water retention.

Modulation of Myostatin/Hepatocyte Growth Factor Balance by Different Hemodialysis Modalities

Background. In this study we investigated the relevance of myostatin and Hepatocyte Growth Factor (HGF) in patients undergoing hemodialysis HD and the influence of different HD modalities on their levels. Methods. We performed a prospective crossover study in which HD patients were randomized to undergo 3-month treatment periods with bicarbonate hemodialysis (BHD) followed by online hemodiafiltration (HDF). Clinical data, laboratory parameters, and myostatin and HGF serum levels were collected and compared. Results. Ten patients and six controls (C) were evaluated. In any experimental condition myostatin and HGF levels were higher in HD than in C. At enrollment and after BHD there were not significant correlations, whereas at the end of the HDF treatment period myostatin and HGF were inversely correlated (r  -0.65, p < 0.05), myostatin serum levels inversely correlated with transferrin (r  -0.73, p < 0.05), and HGF levels that resulted positively correlated with BMI (r 0.67, p < 0.05). Moving from BHD to HDF, clinical and laboratory parameters were unchanged, as well as serum HGF, whereas myostatin levels significantly decreased (6.3 ± 4.1 versus 4.3 ± 3.1 ng/ml, p < 0.05). Conclusions. Modulation of myostatin levels and myostatin/HGF balance by the use of different HD modalities might represent a novel approach to the prevention and treatment of HD-related muscle wasting syndrome.

["Deep" purple urine bag syndrome: physiopathology and clinical implications]

Urinalysis is a key part of the clinical evaluation of patients with kidney disease. It can provide several useful information for the diagnosis and management of diseases of kidneys and urinary tract. In particular, urine color can be affected by the presence of blood, infection and endogenous metabolites, such as bilirubin, or exogenous, for instance those derived from drugs. Therefore, the analysis of urine color may be helpful in identifying different clinical conditions. Here we report a case of a patient who presented purple-colored urine, the so-called " Purple urine bag syndrome", discussing the predisposing factors and the pathogenesis of this condition. We believe that this information can be useful to clinicians who might face this particular situation.

Renal involvement in mushroom poisoning: The case of Orellanus syndrome

Although mushroom poisoning is a rare cause of acute renal injury, in some cases it may lead to the development of a severe and irreversible renal failure. Orellanus syndrome is the most important example of organic renal damage related to mushroom consumption. It is caused by the ingestion of orellanine, the main toxin of different types of Cortinarius mushrooms (Cortinarius speciosissimus, C. orellanus, C. orellanoides, etc.), and it is characterized by progressive clinical phases with a predominant kidney involvement, finally requiring renal replacement therapy in about 10% of cases. Renal damage is often late and associated with a histological picture of interstitial nephritis. Diagnosis is essentially clinical and no specific therapy has been shown to be effective in preventing and treating renal damage. Here, we describe the case of a patient with mixed wild mushroom poisoning, presenting the typical clinical signs and course of the Orellanus syndrome. This case offers us the opportunity to review the main clinical features of this severe and little-known intoxication.

Loss of renal function in the elderly Italians: a physiologic or pathologic process?

BACKGROUND

Nowadays it seems that chronic kidney disease (CKD) is outbreaking, mostly in the elderly participants. The aim of this study was to assess the progression of CKD in different ages.

METHODS

We conducted a monocentric, retrospective, observational study enrolling 116 patients afferent to our outpatient clinic.

INCLUSION CRITERIA

age >18 years, follow-up ≥5 years, estimated glomerular filtration rate (eGFR) <60mL/min/1.73 m(2), and/or diagnosed renal disease and/or presence of renal damage. Patients were divided into four groups according to their age: 25-55 years (n = 27), 56-65 (25), 66-75 (42), and 76-87 (22). eGFR was calculated using the modification of diet in renal disease and the CKD-epidemiology collaboration formulas.

RESULTS

Younger patients had a significantly longer follow-up and less comorbidities, evaluated by the cumulative illness rating scale score, compared with the other groups. There was no difference between creatinine at baseline and at the end-of-follow-up period among the groups. Even though renal function significantly decreased in all groups, we noticed a slower progression as the age increased, and the difference between basal and end-of-follow-up eGFR was minimal in the group of patients aged 76-87 years. Analyzing the eGFR of every ambulatory control plotted against the year of follow-up, we showed a more rapid loss of filtrate in the younger group. Instead, loss of renal function decreased as the age of patients increased.

CONCLUSIONS

This study demonstrates that, in elderly Italian participants, progression of CKD occurs more slowly than in younger patients. This implies that we may probably face an epidemic of CKD but that most of elderly patients diagnosed with CKD may not evolve to end-stage renal disease and require renal replacement therapy.