Understanding patient needs and predicting outcomes in IgA nephropathy using data analytics and artificial intelligence: a narrative review

This narrative review explores two case scenarios related to immunoglobulin A nephropathy (IgAN) and the application of predictive monitoring, big data analysis and artificial intelligence (AI) in improving treatment outcomes. The first scenario discusses how online service providers accurately understand consumer preferences and needs through the use of AI-powered big data analysis. The author, a clinical nephrologist, contemplates the potential application of similar methodologies, including AI, in his medical practice to better understand and meet patient needs. The second scenario presents a case study of a 20-year-old man with IgAN. The patient exhibited recurring symptoms, including gross haematuria and tonsillitis, over a 2-year period. Through histological examination and treatment with renin-angiotensin system blockade and corticosteroids, the patient experienced significant improvement in kidney function and reduced proteinuria over 15 years of follow-up. The case highlights the importance of individualized treatment strategies and the use of predictive tools, such as AI-based predictive models, in assessing treatment response and predicting long-term outcomes in IgAN patients. The article further discusses the collection and analysis of real-world big data, including electronic health records, for studying disease natural history, predicting treatment responses and identifying prognostic biomarkers. Challenges in integrating data from various sources and issues such as missing data and data processing limitations are also addressed. Mathematical models, including logistic regression and Cox regression analysis, are discussed for predicting clinical outcomes and analysing changes in variables over time. Additionally, the application of machine learning algorithms, including AI techniques, in analysing big data and predicting outcomes in IgAN is explored. In conclusion, the article highlights the potential benefits of leveraging AI-powered big data analysis, predictive monitoring and machine learning algorithms to enhance patient care and improve treatment outcomes in IgAN.

Oleogelation of extra virgin olive oil by different gelators affects lipid digestion and polyphenol bioaccessibility

The possibility to steer extra virgin olive oil (EVOO) digestion and polyphenol bioaccessibility through oleogelation was investigated. EVOO was converted into oleogels using lipophilic (monoglycerides, rice wax, sunflower wax, phytosterols) or hydrophilic (whey protein aerogel particles, WP) gelators. In-vitro digestion demonstrated that the oleogelator nature influenced both lipid digestion and polyphenol bioaccessibility. WP-based oleogels presented ∼100% free fatty acid release compared to ∼64% for unstructured EVOO and ∼40 to ∼55% for lipophilic-based oleogels. This behavior was attributed to the ability of WP to promote micelle formation through oleogel destructuring. Contrarily, the lower lipolysis of EVOO gelled with lipophilic gelators compared to unstructured EVOO suggested that the gelator obstructed lipase accessibility. Tyrosol and hydroxytyrosol bioaccessibility increased for WP oleogels (∼27%), while liposoluble-based oleogels reduced it by 7 to 13%. These findings highlight the deep effect of the gelator choice on the digestion fate of EVOO components in the human body.

Circulating metabolites improve the prediction of renal impairment in patients with type 2 diabetes

INTRODUCTION

Low glomerular filtration rate (GFR) is a leading cause of reduced lifespan in type 2 diabetes. Unravelling biomarkers capable to identify high-risk patients can help tackle this burden. We investigated the association between 188 serum metabolites and kidney function in type 2 diabetes and then whether the associated metabolites improve two established clinical models for predicting GFR decline in these patients.

RESEARCH DESIGN AND METHODS

Two cohorts comprising 849 individuals with type 2 diabetes (discovery and validation samples) and a follow-up study of 575 patients with estimated GFR (eGFR) decline were analyzed.

RESULTS

Ten metabolites were independently associated with low eGFR in the discovery sample, with nine of them being confirmed also in the validation sample (ORs range 1.3-2.4 per 1SD, p values range 1.9×10-2-2.5×10-9). Of these, five metabolites were also associated with eGFR decline (ie, tiglylcarnitine, decadienylcarnitine, total dimethylarginine, decenoylcarnitine and kynurenine) (β range -0.11 to -0.19, p values range 4.8×10-2 to 3.0×10-3). Indeed, tiglylcarnitine and kynurenine, which captured all the information of the other three markers, improved discrimination and reclassification (all p<0.01) of two clinical prediction models of GFR decline in people with diabetes.

CONCLUSIONS

Further studies are needed to validate our findings in larger cohorts of different clinical, environmental and genetic background.

Independent Prognostic and Predictive Role of Interstitial Macrophages in Kidney Biopsies of IgA Nephropathy Patients

A relevant percentage of IgAN patients experience a progressive decline in kidney function. According to the KDIGO guidelines, proteinuria and eGFR are the only validated prognostic markers. The role of interstitial macrophages in kidney biopsies of IgAN patients and the outcome of patients treated with renin-angiotensin system inhibitors (RASBs) alone or combined with glucocorticoids were evaluated. Clinical and laboratory records (age, gender, hypertension, hematuria, proteinuria, eGFR, serum creatinine, and therapy), MEST-C parameters of the Oxford classification, C4d deposition, peritubular capillaries, and glomerular and interstitial macrophages in 47 IgAN patients undergoing kidney biopsy consecutively between 2003 and 2016 were examined. A high number of interstitial macrophages significantly correlated with peritubular capillary rarefaction and impairment of kidney function. Cox's multivariable regression analysis revealed that a value > 19.5 macrophages/HPF behaved as an independent marker of an unfavorable outcome. Patients exhibiting > 19.5 macrophages/HPF treated at the time of diagnosis with RASBs combined with methylprednisolone had an estimated probability of a favorable outcome higher than patients treated with RASBs alone. Thus, a value > 19.5 macrophages/HPF in IgAN biopsies can predict an unfavorable outcome and endorse a well-timed administration of glucocorticoids. Studies evaluating urine biomarkers associated with peritubular capillary rarefaction in patients with marked macrophage infiltration may help personalized treatment decisions.

Post-hoc analysis of a tool to predict kidney failure in patients with IgA nephropathy

BACKGROUND

Recently, a tool based on two different artificial neural networks has been developed. The first network predicts kidney failure (KF) development while the second predicts the time frame to reach this outcome. In this study, we conducted a post-hoc analysis to evaluate the discordant results obtained by the tool.

METHODS

The tool performance was analyzed in a retrospective cohort of 1116 adult IgAN patients, as were the causes of discordance between the predicted and observed cases of KF.

RESULTS

There was discordance between the predicted and observed KF in 216 IgAN patients (19.35%) all of whom were elderly, hypertensive, had high serum creatinine levels, reduced renal function and moderate or severe renal lesions. Many of these patients did not receive therapy or were non-responders to therapy. In other IgAN patients the tool predicted KF but the outcome was not reached because patients responded to therapy. Therefore, in the discordant group (prediction did not match the observed outcome) the proportion of patients having or not having KF was strongly associated with treatment (P < 0.0001).

CONCLUSIONS

The post-hoc analysis shows that discordance in a low number of patients is not an error, but rather the effect of positive response to therapy. Thus, the tool could both help physicians to determine the prognosis of the disease and help patients to plan for their future.

Molecular Profiling of Tissue Samples with Chronic Rejection from Patients with Chronic Lung Allograft Dysfunction: A Pilot Study in Cystic Fibrosis Patients

Chronic rejection (CR) is the main culprit for reduced survival and quality of life in patients undergoing lung transplantation (Ltx). High-throughput approaches have been used to unveil the molecular pathways of CR, mainly in the blood and/or in bronchoalveolar lavage. We hypothesized that a distinct molecular signature characterizes the biopsies of recipients with clinically confirmed histological signs of CR. Eighteen cystic fibrosis patients were included in the study and RNA sequencing was performed in 35 scheduled transbronchial biopsies (TBBs): 5 with acute cellular rejection, 9 with CR, and 13 without any sign of post-LTx complication at the time of biopsy; 8 donor lung samples were used as controls. Three networks with 33, 26, and 36 differentially expressed genes (DEGs) were found in TBBs with CR. Among these, seven genes were common to the identified pathways and possibly linked to CR and five of them (LCN2, CCL11, CX3CL1, CXCL12, MUC4) were confirmed by real-time PCR. Immunohistochemistry was significant for LCN2 and MUC4. This study identified a typical gene expression pattern in TBBs with histological signs of CR and the LCN2 gene appeared to play a central role. Thus, it could be crucial in CR pathophysiology.

Prediction of chronic kidney disease and its progression by artificial intelligence algorithms

BACKGROUND AND OBJECTIVE

Aim of nephrologists is to delay the outcome and reduce the number of patients undergoing renal failure (RF) by applying prevention protocols and accurately monitoring chronic kidney disease (CKD) patients. General practitioners and nephrologists are involved in the first and in the late stages of the disease, respectively. Early diagnosis of CKD is an important step in preventing the progression of kidney damage. Our aim was to review publications on machine learning algorithms (MLAs) that can predict early CKD and its progression.

METHODS

We conducted a systematic review and selected 55 articles on the application of MLAs in CKD. PubMed, Medline, Scopus, Web of Science and IEEE Xplore Digital Library of the Institute of Electrical and Electronics Engineers were searched. The search terms were chronic kidney disease, artificial intelligence, data mining and machine learning algorithms.

RESULTS

MLAs use enormous numbers of predictors combining them in non-linear and highly interactive ways. This ability increases when new data is added. We observed some limitations in the publications: (i) databases were not accurately reviewed by physicians; (ii) databases did not report the ethnicity of the patients; (iii) some databases collected variables that were not important for the diagnosis and progression of CKD; (iv) no information was presented on the native kidney disease causing CKD; (v) no validation of the results in external independent cohorts was provided; and (vi) no insights were given on the MLAs that were used. Overall, there was limited collaboration among experts in electronics, computer science and physicians.

CONCLUSIONS

The application of MLAs in kidney diseases may enhance the ability of clinicians to predict CKD and RF, thus improving diagnostic assistance and providing suitable therapeutic decisions. However, it is necessary to improve the development process of MLA tools.

FC048: New Tool to Predict the Clinical Course and Renal Failure in Patients with Immunoglobulin a Nephropathy

BACKGROUND AND AIMS

Idiopathic Immunoglobulin A nephropathy (IgAN) is the most common biopsy-proven glomerulonephritis in the world. Approximately 40% of IgAN patients reach renal failure (RF) 20 years after their kidney biopsy. The high prevalence of RF shows that IgAN has a significant economic impact in the countries because renal replacement therapy is costly. Moreover, the disease's onset in the second and third decades of life represents a social challenge because patients are typically very active and highly productive in the workplace. This challenge is one more reason to move on the prediction of the clinical course and RF in IgAN patients at the time of the kidney biopsy and during the follow-up. We developed an artificial neural network (ANN) tool (DialCheck 1.0) based on seven variables and the histological score of the kidney biopsy to predict RF in IgAN patients at the time of kidney biopsy [1].

METHOD

We have recently developed a new tool which consists of a set of ANN-powered models that combine temporally accurate observations for fine-grained features and leverage state-of-the-art deep neural network techniques to forecast the patient's clinical evolution.

RESULTS

A cohort of 948 IgAN patients, of whom the clinical course of the disease was known, was used to develop the new tool that predicts the dynamics of age and disease laboratory parameters (serum creatinine, daily proteinuria), blood pressure, histological score of the kidney biopsy and the RF. The system was designed to help the physicians give a broader spectrum of information regarding the patient and the potential clinical development of IgAN and outcomes.

In detail, the model computes a latent dynamic representation of the patient and predicts a prospective clinical picture of the patient and the probability of RF. The tool with an accuracy of &gt;80% will be tested in an independent retrospective cohort of 454 IgAN patients and in a prospective multicenter randomized clinical study in which 426 IgAN patients will be enrolled in two different groups based on the type of kidney lesions (active and chronic renal lesions).

CONCLUSION

We have a new tool (DialCheck 2.0), based on ANN, that may predict the outcome and the RF in IgAN patients. Moreover, it may help the physician to analyze the long-term response to therapy.

[The origins of the Renal Immunopathology Group of the Italian Society of Nephrology]

This article describes the birth and development of the Renal Immunopathology Group of the Italian Society of Nephrology. It collects the stories of nephrologists and pathologists who, since the early Seventies up to the first decade of this century, devoted their professional lives to the study of renal pathology with a strong personal involvement, characterized by enthusiasm, commitment, ability, strong spirit of cooperation, and friendship. All this enabled the Group to: propose the criteria for a standardized histological and immuno-histological examination of renal biopsies and reporting; produce several multicenter studies, whose results were also published in important international journals; to set up a national registry of renal biopsies; to organize a number of courses, some of which were associated with the publication of monographs, on various renal diseases. This article also traces the history of renal pathology in Italy from the second half of the Sixties - when young Italian nephrologists and pathologists from different institutions moved to French laboratories to learn new techniques to apply to renal biopsies - up to the present days. It also shows us how Italian renal pathology has been an essential tool for the development of the nephrological clinical practice and the advancement of scientific research.

MO260PERFORMANCE ANALYSIS OF AN ARTIFICIAL NEURAL NETWORK TOOL TO PREDICT ESKD IN PATIENTS WITH IMMUNOGLOBULIN A NEPHROPATHY (IGAN)

Background

During the last twenty years many tools, based on mathematical models, have been developed to predict ESKD at the time of kidney biopsy in patients with IgAN. The main limitation of these tools is the time frame to reach the ESKD. Recently, we have developed a Clinical Decision Support System (CDSS) (KI 2020) which includes 6 variables at the time of kidney biopsy: age, sex, hypertension, serum creatinine, daily proteinuria and score of the renal lesions according to the MEST-C classification. The tool (www.igan.poliba.it) is based on two different artificial neural networks of which the first predicts ESKD and the second one predicts the time to reach this outcome.

Aim

of our study has been to analyze the causes of discordance to predict or not ESKD in a cohort of 1116 IgAN patients (VALIGA cohort and external cohort) with a median follow-up of 88 months (49-135). To our knowledge this is the first report which analyzes the discrepant results of a toll to predict ESKD in IgAN patients.

Method

Demographic and laboratory data have been analyzed using means and standard deviations (SD) for continuous variables normally distributed, median in presence of non-normally distribution. Categorical variables are expressed as percentages. The means have been compared by the Student’s test and the medians using the Mann-Whitney U test. All the data were collected and stored in a standard Excel database. The statistical significance value p&lt; 0.05 has been adopted.

Results

Discordance to reach or not ESKD was found in 216 patients (19.4%). In 77 patients with no prediction of ESKD, 25 patients with proteinuria &gt; 0.5 g/day did not receive therapy after kidney biopsy or were cared very late. Failure of therapy (RASBs alone in 44 subjects and corticosteroids in 8 individuals) was observed in 52 patients. In 139 patients who did not reach ESKD but our tool predicted this outcome, interestingly, we found that 106 proteinuric patients (22 with GFR &gt;50 ml/min/1.73 m2 and 84 with GFR &lt; 50 ml/min/1.73 m2) had an improvement of the clinical course (reduction of proteinuria and stabilization of GFR value) after corticosteroid therapy. The remaining 33 patients benefited of RASB therapy. Among 84 patients with GFR&lt; 50 ml/min/1.73 m2 36 had nephrotic proteinuria and were responsive to corticosteroids. These results suggest that we cannot rule out corticosteroid therapy in patients with reduced GFR and proteinuria &gt; 3 g/day. Furthermore, our tool predicts the time frame to reach ESKD and indicates the potential effect of some drugs (RASBs, corticosteroids or their combination) to delay the outcome. We observed that corticosteroids combined with RASBs delayed more than 10 years the time to reach ESKD.

Conclusions

Our tool predicted ESKD in a percentage higher than that observed but, interestingly, it was found that a high number of patients benefited of corticosteroids in combination with RASBs. Furthermore, our tool predicted time to reach ESKD and indicated the potential benefit of therapy to delay the crude outcome. In fact, therapy delayed the outcome of more than 10 years when combination of corticosteroids and RASBs was administered. Therefore, our tool shows to physicians that their patients may delay the ESKD receiving corticosteroids alone or in combination with RASBs. This approach is important because in many cases it is a strengthen point to convince patients to accept the prescribed therapy. Moreover, this report shows for the first time that predicted ESKD may be delayed administering personalized therapy suggested by our tool. Essentially, in a high percentage of patients the failure of our tool is not an error but the positive effect of therapy or misconduct of patients management.

Formalin-fixed paraffin-embedded renal biopsy tissues: an underexploited biospecimen resource for gene expression profiling in IgA nephropathy

Primary IgA nephropathy (IgAN) diagnosis is based on IgA-dominant glomerular deposits and histological scoring is done on formalin-fixed paraffin embedded tissue (FFPE) sections using the Oxford classification. Our aim was to use this underexploited resource to extract RNA and identify genes that characterize active (endocapillary–extracapillary proliferations) and chronic (tubulo-interstitial) renal lesions in total renal cortex. RNA was extracted from archival FFPE renal biopsies of 52 IgAN patients, 22 non-IgAN and normal renal tissue of 7 kidney living donors (KLD) as controls. Genome-wide gene expression profiles were obtained and biomarker identification was carried out comparing gene expression signatures a subset of IgAN patients with active (N = 8), and chronic (N = 12) renal lesions versus non-IgAN and KLD. Bioinformatic analysis identified transcripts for active (DEFA4,TNFAIP6,FAR2) and chronic (LTB,CXCL6, ITGAX) renal lesions that were validated by RT-PCR and IHC. Finally, two of them (TNFAIP6 for active and CXCL6 for chronic) were confirmed in the urine of an independent cohort of IgAN patients compared with non-IgAN patients and controls. We have integrated transcriptomics with histomorphological scores, identified specific gene expression changes using the invaluable repository of archival renal biopsies and discovered two urinary biomarkers that may be used for specific clinical decision making.

Development and testing of an artificial intelligence tool for predicting end-stage kidney disease in patients with immunoglobulin A nephropathy

We have developed an artificial neural network prediction model for end-stage kidney disease (ESKD) in patients with primary immunoglobulin A nephropathy (IgAN) using a retrospective cohort of 948 patients with IgAN. Our tool is based on a two-step procedure of a classifier model that predicts ESKD, and a regression model that predicts development of ESKD over time. The classifier model showed a performance value of 0.82 (area under the receiver operating characteristic curve) in patients with a follow-up of five years, which improved to 0.89 at the ten-year follow-up. Both models had a higher recall rate, which indicated the practicality of the tool. The regression model showed a mean absolute error of 1.78 years and a root mean square error of 2.15 years. Testing in an independent cohort of 167patients with IgAN found successful results for 91% of the patients. Comparison of our system with other mathematical models showed the highest discriminant Harrell C index at five- and ten-years follow-up (81% and 86%, respectively), paralleling the lowest Akaike information criterion values (355.01 and 269.56, respectively). Moreover, our system was the best calibrated model indicating that the predicted and observed outcome probabilities did not significantly differ. Finally, the dynamic discrimination indexes of our artificial neural network, expressed as the weighted average of time-dependent areas under the curve calculated at one and two years, were 0.80 and 0.79, respectively. Similar results were observed over a 25-year follow-up period. Thus, our tool identified individuals who were at a high risk of developing ESKD due to IgAN and predicted the time-to-event endpoint. Accurate prediction is an important step toward introduction of a therapeutic strategy for improving clinical outcomes.

Immunosuppressive agents for treating IgA nephropathy

BACKGROUND

IgA nephropathy is the most common glomerulonephritis world-wide. IgA nephropathy causes end-stage kidney disease (ESKD) in 15% to 20% of affected patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a Cochrane review first published in 2003 and updated in 2015.

OBJECTIVES

To determine the benefits and harms of immunosuppression strategies for the treatment of IgA nephropathy.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 9 September 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgA nephropathy in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risk of bias and extracted data. Estimates of treatment effect were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Risks of bias were assessed using the Cochrane tool. Evidence certainty was evaluated using GRADE methodology.

MAIN RESULTS

Fifty-eight studies involving 3933 randomised participants were included. Six studies involving children were eligible. Disease characteristics (kidney function and level of proteinuria) were heterogeneous across studies. Studies evaluating steroid therapy generally included patients with protein excretion of 1 g/day or more. Risk of bias within the included studies was generally high or unclear for many of the assessed methodological domains. In patients with IgA nephropathy and proteinuria > 1 g/day, steroid therapy given for generally two to four months with a tapering course probably prevents the progression to ESKD compared to placebo or standard care (8 studies; 741 participants: RR 0.39, 95% CI 0.23 to 0.65; moderate certainty evidence). Steroid therapy may induce complete remission (4 studies, 305 participants: RR 1.76, 95% CI 1.03 to 3.01; low certainty evidence), prevent doubling of serum creatinine (SCr) (7 studies, 404 participants: RR 0.43, 95% CI 0.29 to 0.65; low certainty evidence), and may lower urinary protein excretion (10 studies, 705 participants: MD -0.58 g/24 h, 95% CI -0.84 to -0.33;low certainty evidence). Steroid therapy had uncertain effects on glomerular filtration rate (GFR), death, infection and malignancy. The risk of adverse events with steroid therapy was uncertain due to heterogeneity in the type of steroid treatment used and the rarity of events. Cytotoxic agents (azathioprine (AZA) or cyclophosphamide (CPA) alone or with concomitant steroid therapy had uncertain effects on ESKD (7 studies, 463 participants: RR 0.63, 95% CI 0.33 to 1.20; low certainty evidence), complete remission (5 studies; 381 participants: RR 1.47, 95% CI 0.94 to 2.30; very low certainty evidence), GFR (any measure), and protein excretion. Doubling of serum creatinine was not reported. Mycophenolate mofetil (MMF) had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, infection, and malignancy. Death was not reported. Calcineurin inhibitors compared with placebo or standard care had uncertain effects on complete remission, SCr, GFR, protein excretion, infection, and malignancy. ESKD and death were not reported. Mizoribine administered with renin-angiotensin system inhibitor treatment had uncertain effects on progression to ESKD, complete remission, GFR, protein excretion, infection, and malignancy. Death and SCr were not reported. Leflunomide followed by a tapering course with oral prednisone compared to prednisone had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, and infection. Death and malignancy were not reported. Effects of other immunosuppressive regimens (including steroid plus non-immunosuppressive agents or mTOR inhibitors) were inconclusive primarily due to insufficient data from the individual studies in low or very low certainty evidence. The effects of treatments on death, malignancy, reduction in GFR at least of 25% and adverse events were very uncertain. Subgroup analyses to determine the impact of specific patient characteristics such as ethnicity or disease severity on treatment effectiveness were not possible.

AUTHORS' CONCLUSIONS

In moderate certainty evidence, corticosteroid therapy probably prevents decline in GFR or doubling of SCr in adults and children with IgA nephropathy and proteinuria. Evidence for treatment effects of immunosuppressive agents on death, infection, and malignancy is generally sparse or low-quality. Steroid therapy has uncertain adverse effects due to a paucity of studies. Available studies are few, small, have high risk of bias and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible due to a lack of studies. There is no evidence that other immunosuppressive agents including CPA, AZA, or MMF improve clinical outcomes in IgA nephropathy.

A Narrative Review on C3 Glomerulopathy: A Rare Renal Disease

In April 2012, a group of nephrologists organized a consensus conference in Cambridge (UK) on type II membranoproliferative glomerulonephritis and decided to use a new terminology, "C3 glomerulopathy" (C3 GP). Further knowledge on the complement system and on kidney biopsy contributed toward distinguishing this disease into three subgroups: dense deposit disease (DDD), C3 glomerulonephritis (C3 GN), and the CFHR5 nephropathy. The persistent presence of microhematuria with or without light or heavy proteinuria after an infection episode suggests the potential onset of C3 GP. These nephritides are characterized by abnormal activation of the complement alternative pathway, abnormal deposition of C3 in the glomeruli, and progression of renal damage to end-stage kidney disease. The diagnosis is based on studying the complement system, relative genetics, and kidney biopsies. The treatment gap derives from the absence of a robust understanding of their natural outcome. Therefore, a specific treatment for the different types of C3 GP has not been established. Recommendations have been obtained from case series and observational studies because no randomized clinical trials have been conducted. Current treatment is based on corticosteroids and antiproliferative drugs (cyclophosphamide, mycophenolate mofetil), monoclonal antibodies (rituximab) or complement inhibitors (eculizumab). In some cases, it is suggested to include sessions of plasma exchange.

Omics studies for comprehensive understanding of immunoglobulin A nephropathy: state-of-the-art and future directions

Immunoglobulin A nephropathy (IgAN) is the most common worldwide primary glomerulonephritis with a strong autoimmune component. The disease shows variability in both clinical phenotypes and endpoints and can be potentially subdivided into more homogeneous subtypes through the identification of specific molecular biomarkers. This review focuses on the role of omics in driving the identification of potential molecular subtypes of the disease through the integration of multilevel data from genomics, transcriptomics, epigenomics, proteomics and metabolomics. First, the identification of molecular biomarkers, including mapping of the full spectrum of common and rare IgAN risk alleles, could permit a more precise stratification of IgAN patients. Second, the analysis of transcriptomic patterns and their modulation by epigenetic factors like microRNAs has the potential to increase our understanding in the pathogenic mechanisms of the disease. Third, the specificity of urinary proteomic and metabolomic signatures and the understanding of their functional relevance may contribute to the development of new non-invasive biomarkers for a better molecular characterization of the renal damage and its follow-up. All these approaches can give information for targeted therapeutic decisions and will support novel clinical decision making. In conclusion, we offer a framework of omic studies and outline barriers and potential solutions that should be used for improving the diagnosis and treatment of the disease. The ongoing decade is exploiting novel high-throughput molecular technologies and computational analyses for improving the diagnosis (precision nephrology) and treatment (personalized therapy) of the IgAN subtypes.

Catheter type, placement and insertion techniques for preventing catheter-related infections in chronic peritoneal dialysis patients

BACKGROUND

Peritonitis is one of the limiting factors for the growth of peritoneal dialysis (PD) worldwide and is a major cause of technique failure. Several studies have examined the effectiveness of various catheter-related interventions for lowering the risk of PD-related peritonitis. This is an update of a review first published in 2004.

OBJECTIVES

To evaluate the role of different catheter implantation techniques and catheter types in lowering the risk of PD-related peritonitis in PD patients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 15 January 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Studies comparing different catheter insertion techniques, catheter types, use of immobilisation techniques and different break-in periods were included. Studies of different PD sets were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using a random effects model and the results expressed as risk ratio (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Forty-two studies (3144 participants) were included: 18 evaluated techniques of catheter implantation, 22 examined catheter types, one assessed an immobiliser device, and one examined break-in period. In general, study quality was variable and almost all aspects of study design did not fulfil CONSORT standards for reporting.Catheter insertion by laparoscopy compared with laparotomy probably makes little or no difference to the risks of peritonitis (RR 0.90, 95% CI 0.59 to 1.35; moderate certainty evidence), exit-site/tunnel infection (RR 1.00, 95% CI 0.43 to 2.31; low certainty evidence), catheter removal/replacement (RR 1.20, 95% CI 0.77 to 1.86; low certainty evidence), technique failure (RR 0.71, 95% CI 0.47 to 1.08; low certainty evidence), and death (all causes) (RR 1.26, 95% CI 0.72 to 2.20; moderate certainty evidence). It is uncertain whether subcutaneous burying of catheter increases peritonitis (RR 1.16, 95% CI 0.37 to 3.60; very low certainty evidence). Midline insertion compared to lateral insertion probably makes little or no difference to the risks of peritonitis (RR 0.65, 95% CI 0.32 to 1.33; moderate certainty evidence) and may make little or no difference to exit-site/tunnel infection (RR 0.56, 95% CI 0.12 to 2.58; low certainty evidence). Percutaneous insertion compared with open surgery probably makes little or no difference to the exit-site/tunnel infection (RR 0.16, 95% CI 0.02 to 1.30; moderate certainty evidence).Straight catheters probably make little or no difference to the risk of peritonitis (RR 1.04, 95% CI 0.82 to 1.31; moderate certainty evidence), peritonitis rate (RR 0.91, 95% CI 0.68 to 1.21; moderate certainty evidence), risk of exit-site infection (RR 1.12, 95% CI 0.94 to 1.34; moderate certainty evidence), and exit-site infection rate (RR 1.05, 95% CI 0.77 to 1.43; moderate certainty evidence) compared to coiled catheter. It is uncertain whether straight catheters prevent catheter removal or replacement (RR 1.11, 95% CI 0.73 to 1.66; very low certainty evidence) but straight catheters probably make little or no difference to technique failure (RR 0.82, 95% CI 0.51 to 1.31; moderate certainty evidence) and death (all causes) (RR 0.95, 95% CI 0.62 to 1.46; low certainty evidence) compared to coiled catheter. Tenckhoff catheter with artificial curve at subcutaneous tract compared with swan-neck catheter may make little or no difference to peritonitis (RR 1.29, 95% CI 0.85 to 1.96; low certainty evidence) and incidence of exit-site/tunnel infection (RR 0.96, 95% CI 0.77 to 1.21; low certainty evidence) but may slightly improve exit-site infection rate (RR 0.67, 95% CI 0.50 to 0.90; low certainty evidence).

AUTHORS' CONCLUSIONS

There is no strong evidence that any catheter-related intervention, including the use of different catheter types or different insertion techniques, reduces the risks of PD peritonitis or other PD-related infections, technique failure or death (all causes). However, the numbers and sizes of studies were generally small and the methodological quality of available studies was suboptimal, such that the possibility that a particular catheter-related intervention might have a beneficial effect cannot be completely ruled out with confidence.

Biomarkers and Precision Medicine in IgA Nephropathy

The field of biomarker research in IgA nephropathy has experienced a major boost in recent years with the publication of a large number of scientific reports. Candidate biomarkers from blood, urine, and renal tissue obtained through the use of clinical chemistry, molecular biology, and omics have been proposed for translation in clinical practice. Nevertheless, individual biomarkers often lack sensitivity and specificity with the consequent impairment of disease specificity. This review, moving on from the analysis of the four-hit hypothesis, illustrates the biomarkers linked to the abnormal glycosylation process of IgA1 and the immune complex formation. It also describes other serum and urinary biomarkers. Given the profound insights into the pleiotropic function of a single biomarker that is specific for a pathophysiological mechanism, this review suggests a novel approach based on a panel of biomarkers that covers the entire pathogenic process of the disease. Clinical bioinformatics that integrate genetic, clinical, and bioinformatics data sets could optimize the specific value of each biomarker in a multimarker panel. This is a promising approach for precision medicine and personalized therapy in IgA nephropathy.

Epidemiology of IgA Nephropathy: A Global Perspective

IgA nephropathy (IgAN), or Berger's disease, is the most common primary glomerular disease worldwide, but varies largely in its geographic distribution. A systematic review of 1,619 publications from the five continental regions of the world was performed to assess the prevalence of IgAN in different worldwide regions and analyze factors responsible for geographic differences. All observational studies that described the prevalence and incidence data on glomerulonephritis were considered. IgAN is more frequent in Asian populations (45 cases per million population/y in Japan) than in Caucasians (31 cases per million population/y in France). These differences are owing to some relevant aspects: (1) systematic mass screening of urine in populations, as occurring in some Asian countries (Hong Kong, Japan, Korea, and Singapore), is not common in Western countries; (2) general practitioners and health care professionals in Western countries underestimate persistent microscopic hematuria and/or mild proteinuria in apparently healthy individuals causing late referral to a nephrologist; and (3) nephrologists adopt different indications for kidney biopsy in individuals with persistent urinary abnormalities. In addition, differences also are owing to the source of data, because the frequency of IgAN observed in a nephrology center with a high incidence of kidney biopsies is higher than in a regional renal biopsy registry that receives data from many centers. In conclusion, greater efforts should be made to diagnose IgAN earlier in individuals who manifest persistent microhematuria and/or mild proteinuria and to introduce less stringent indications for kidney biopsies. This preventive approach, followed by early therapy, may reduce the global burden of end-stage kidney disease caused by IgAN.

Change in albuminuria as a surrogate endpoint for progression of kidney disease: a meta-analysis of treatment effects in randomised clinical trials

BACKGROUND

Change in albuminuria has strong biological plausibility as a surrogate endpoint for progression of chronic kidney disease, but empirical evidence to support its validity is lacking. We aimed to determine the association between treatment effects on early changes in albuminuria and treatment effects on clinical endpoints and surrograte endpoints, to inform the use of albuminuria as a surrogate endpoint in future randomised controlled trials.

METHODS

In this meta-analysis, we searched PubMed for publications in English from Jan 1, 1946, to Dec 15, 2016, using search terms including "chronic kidney disease", "chronic renal insufficiency", "albuminuria", "proteinuria", and "randomized controlled trial"; key inclusion criteria were quantifiable measurements of albuminuria or proteinuria at baseline and within 12 months of follow-up and information on the incidence of end-stage kidney disease. We requested use of individual patient data from the authors of eligible studies. For all studies that the authors agreed to participate and that had sufficient data, we estimated treatment effects on 6-month change in albuminuria and the composite clinical endpoint of treated end-stage kidney disease, estimated glomerular filtration rate of less than 15 mL/min per 1·73 m², or doubling of serum creatinine. We used a Bayesian mixed-effects meta-regression analysis to relate the treatment effects on albuminuria to those on the clinical endpoint across studies and developed a prediction model for the treatment effect on the clinical endpoint on the basis of the treatment effect on albuminuria.

FINDINGS

We identified 41 eligible treatment comparisons from randomised trials (referred to as studies) that provided sufficient patient-level data on 29 979 participants (21 206 [71%] with diabetes). Over a median follow-up of 3·4 years (IQR 2·3-4·2), 3935 (13%) participants reached the composite clinical endpoint. Across all studies, with a meta-regression slope of 0·89 (95% Bayesian credible interval [BCI] 0·13-1·70), each 30% decrease in geometric mean albuminuria by the treatment relative to the control was associated with an average 27% lower hazard for the clinical endpoint (95% BCI 5-45%; median R² 0·47, 95% BCI 0·02-0·96). The association strengthened after restricting analyses to patients with baseline albuminuria of more than 30 mg/g (ie, 3·4 mg/mmol; R² 0·72, 0·05-0·99]). For future trials, the model predicts that treatments that decrease the geometric mean albuminuria to 0·7 (ie, 30% decrease in albuminuria) relative to the control will provide an average hazard ratio (HR) for the clinical endpoint of 0·68, and 95% of sufficiently large studies would have HRs between 0·47 and 0·95.

INTERPRETATION

Our results support a role for change in albuminuria as a surrogate endpoint for the progression of chronic kidney disease, particularly in patients with high baseline albuminuria; for patients with low baseline levels of albuminuria this association is less certain.

FUNDING

US National Kidney Foundation.

Inhibin-A and Decorin Secreted by Human Adult Renal Stem/Progenitor Cells Through the TLR2 Engagement Induce Renal Tubular Cell Regeneration

Acute kidney injury (AKI) is a public health problem worldwide. Several therapeutic strategies have been made to accelerate recovery and improve renal survival. Recent studies have shown that human adult renal progenitor cells (ARPCs) participate in kidney repair processes, and may be used as a possible treatment to promote regeneration in acute kidney injury. Here, we show that human tubular ARPCs (tARPCs) protect physically injured or chemically damaged renal proximal tubular epithelial cells (RPTECs) by preventing cisplatin-induced apoptosis and enhancing proliferation of survived cells. tARPCs without toll-like receptor 2 (TLR2) expression or TLR2 blocking completely abrogated this regenerative effect. Only tARPCs, and not glomerular ARPCs, were able to induce tubular cell regeneration process and it occurred only after damage detection. Moreover, we have found that ARPCs secreted inhibin-A and decorin following the RPTEC damage and that these secreted factors were directly involved in cell regeneration process. Polysaccharide synthetic vesicles containing these molecules were constructed and co-cultured with cisplatin damaged RPTECs. These synthetic vesicles were not only incorporated into the cells, but they were also able to induce a substantial increase in cell number and viability. The findings of this study increase the knowledge of renal repair processes and may be the first step in the development of new specific therapeutic strategies for renal repair.

Multiple rare genetic variants co-segregating with familial IgA nephropathy all act within a single immune-related network

BACKGROUND

IgA nephropathy (IgAN) is a common complex disease with a strong genetic involvement. We aimed to identify novel, rare, highly penetrant risk variants combining family-based linkage analysis with whole-exome sequencing (WES).

METHODS

Linkage analysis of 16 kindreds of South Italian ancestry was performed using an 'affected-only' strategy. Eight most informative trios composed of two familial cases and an intrafamilial control were selected for WES. High-priority variants in linked regions were identified and validated using Sanger sequencing. Custom TaqMan assays were designed and carried out in the 16 kindreds and an independent cohort of 240 IgAN patients and 113 control subjects.

RESULTS

We found suggestive linkage signals in 12 loci. After sequential filtering and validation of WES data, we identified 24 private or extremely rare (MAF <0.0003) linked variants segregating with IgAN status. These were present within coding or regulatory regions of 23 genes that merged into a common functional network. The genes were interconnected by AKT, CTNNB1, NFKB, MYC and UBC, key modulators of WNT/β-catenin and PI3K/Akt pathways, which are implicated in IgAN pathogenesis. Overlaying publicly available expression data, genes/proteins with expression notably altered in IgAN were included in this immune-related network. In particular, the network included the glucocorticoid receptor gene, NR3C1, which is the target of corticosteroid therapy routinely used in the treatment of IgAN.

CONCLUSION

Our findings suggest that disease susceptibility could be influenced by multiple rare variants acting in a common network that could provide the starting point for the identification of potential drug targets for personalized therapy.

Cultivar classification of Apulian olive oils: Use of artificial neural networks for comparing NMR, NIR and merceological data

The development of an efficient and accurate method for extra-virgin olive oils cultivar and origin authentication is complicated by the broad range of variables (e.g., multiplicity of varieties, pedo-climatic aspects, production and storage conditions) influencing their properties. In this study, artificial neural networks (ANNs) were applied on several analytical datasets, namely standard merceological parameters, near-infra red data and ¹H nuclear magnetic resonance (NMR) fingerprints, obtained on mono-cultivar olive oils of four representative Apulian varieties (Coratina, Ogliarola, Cima di Mola, Peranzana). We analyzed 888 samples produced at a laboratory-scale during two crop years from 444 plants, whose variety was genetically ascertained, and on 17 industrially produced samples. ANN models based on NMR data showed the highest capability to classify cultivars (in some cases, accuracy>99%), independently on the olive oil production process and year; hence, the NMR data resulted to be the most informative variables about the cultivars.

Clinical Application of Human Urinary Extracellular Vesicles in Kidney and Urologic Diseases

Extracellular vesicles (EVs) have been isolated in different body fluids, including urine. The cargo of urinary EVs is composed of nucleic acids and proteins reflecting the physiological and possibly pathophysiological state of cells lining the nephron and the urinary tract. Urinary EVs have been confirmed to contain low amounts of various types of RNA that play a role in intercellular communication by transferring genetic information. This communication through EV RNAs includes both continuation of normal physiological processes and conditioning in disease mechanisms. Although proteins included in urinary EVs represent only 3% of the whole-urine proteome, urinary EVs can influence cells in the renal epithelia not only by delivering RNA cargo, but also by delivering a wide range of proteins. Since urine is a readily available biofluid, the discovery of EVs has opened a new field of biomarker research. The potential use of urinary EV RNAs and proteins as diagnostic biomarkers for various kidney and urologic diseases is currently being explored. Here, we review recent studies that deal in identifying biomarker candidates for human kidney and urologic diseases using urinary EVs and might help to understand the pathophysiology.

Renal Cell Carcinoma: A Study through NMR-Based Metabolomics Combined with Transcriptomics

Renal cell carcinoma (RCC) is a heterogeneous cancer often showing late symptoms. Until now, some candidate protein markers have been proposed for its diagnosis. Metabolomics approaches have been applied, predominantly using Mass Spectrometry (MS), while Nuclear Magnetic Resonance (NMR)-based studies remain limited. There is no study about RCC integrating NMR-based metabolomics with transcriptomics. In this work, ¹H-NMR spectroscopy combined with multivariate statistics was applied on urine samples, collected from 40 patients with clear cell RCC (ccRCC) before nephrectomy and 29 healthy controls; nine out of 40 patients also provided samples one-month after nephrectomy. We observed increases of creatine, alanine, lactate and pyruvate, and decreases of hippurate, citrate, and betaine in all ccRCC patients. A network analysis connected most of these metabolites with glomerular injury, renal inflammation and renal necrosis/cell death. Interestingly, intersecting metabolites with transcriptomic data from CD133+/CD24+ tumoral renal stem cells isolated from ccRCC patients, we found that both genes and metabolites differentially regulated in ccRCC patients belonged to HIF-α signaling, methionine and choline degradation, and acetyl-CoA biosynthesis. Moreover, when comparing urinary metabolome of ccRCC patients after nephrectomy, some processes, such as the glomerular injury, renal hypertrophy, renal necrosis/cell death and renal proliferation, were no more represented.

[Cardiovascular risk in polycystic kidney disease]

Hypertension is common and occurs in the majority of autosomal dominant polycystic kidney disease (ADPKD) patients prior to loss of kidney function. Hypertension relates to progressive kidney enlargement, and is a significant independent risk factor for progression to end-stage renal disease. The pathogenesis of hypertension in ADPKD is complex and depends on many factors that influence each other. High expression of PKD1 and PKD2 genes is present in the cilia of tubular epithelial cells, in endothelial cells and in vascular smooth muscle cells. Decreased or absent polycystin-1 or -2 expression is associated with abnormal vascular structure and function. PKD1/PKD2 deficiency results in reduced nitric oxide levels, altered endothelial response to shear stress with attenuation in vascular relaxation. Activation of the renin-angiotensin-aldosterone system occurs in ADPKD due to decreased nitric oxide production as well as bilateral cyst expansion and intra-renal ischemia. With increasing cyst size, further activation of the renin-angiotensin-aldosterone system occurs, blood pressure increases and a vicious cycle ensues with enhanced cyst growth and hypertension ultimately leading to end-stage renal disease. Inhibition of the angiotensin-aldosterone system is possible with angiotensin-converting enzyme inhibitors and seems to be the first-line treatment for hypertension in these subjects. As suggested by the HALT-PKD study, an aggressive blood pressure control is safe and recommended and is associated with preservation of kidney function and a reduction in total kidney volume over time. A collaborative multidisciplinary approach between nephrologists and cardiologists is necessary for the monitoring of kidney and heart complications.

Patient classification and outcome prediction in IgA nephropathy

OBJECTIVE

IgA Nephropathy (IgAN) is a common kidney disease which may entail renal failure, known as End Stage Kidney Disease (ESKD). One of the major difficulties dealing with this disease is to predict the time of the long-term prognosis for a patient at the time of diagnosis. In fact, the progression of IgAN to ESKD depends on an intricate interrelationship between clinical and laboratory findings. Therefore, the objective of this work has been the selection of the best data mining tool to build a model able to predict (I) if a patient with a biopsy proven IgAN will reach ESKD and (II) if a patient will reach the ESKD before or after 5 years.

MATERIAL AND METHODS

The largest available cohort study worldwide on IgAN has been used to design and compare several data-driven models. The complete dataset was composed of 1174 records collected from Italian, Norwegian, and Japanese IgAN patients, in the last 30 years. The data mining tools considered in this work were artificial neural networks (ANNs), neuro fuzzy systems (NFSs), support vector machines (SVMs), and decision trees (DTs). A 10-fold cross validation was used to evaluate unbiased performances for all the models.

RESULTS

An extensive model comparison based on accuracy, precision, recall, and f-measure was provided. Overall, the results indicate that ANNs can provide superior performance compared to the other models. The ANN for time-to-ESKD prediction is characterized by accuracy, precision, recall, and f-measure greater than 90%. The ANN for ESKD prediction has accuracy greater than 90% as well as precision, recall, and f-measure for the class of patients not reaching ESKD, while precision, recall, and f-measure for the class of patients reaching ESKD are slightly lower. The obtained model has been implemented in a Web-based decision support system (DSS).

CONCLUSIONS

The extraction of novel knowledge from clinical data and the definition of predictive models to support diagnosis, prognosis, and therapy is becoming an essential tool for researchers and clinical practitioners in medicine. The proposed comparative study of several data mining models for the outcome prediction in IgAN patients, using a large dataset of clinical records from three different countries, provides an insight into the relative prediction ability of the considered methods applied to such a disease.

Immunosuppressive agents for treating IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is the most common glomerulonephritis world-wide and a cause of end-stage kidney disease (ESKD) in 15% to 20% of patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a review first published in 2003.

OBJECTIVES

To determine the benefits and harms of immunosuppression for the treatment of IgAN.

SEARCH METHODS

For this review update we searched the Specialised Register to 19 February 2015 through contact with the Trials Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgAN in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risk of bias and extracted data for population characteristics, interventions and outcomes including mortality, infection, hospitalisation, ESKD requiring renal replacement therapy (dialysis or kidney transplantation), doubling of serum creatinine, remission of proteinuria, and end of treatment urinary protein excretion, serum creatinine, and glomerular filtration rate.Estimates of treatment effect and hazards were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included 32 studies comprising 1781 participants. Risk of bias within the included studies was generally high: 22 studies (69%) did not describe the method used to generate the randomisation sequence; 24 (75%) did not describe the methods used to conceal allocation; performance bias was not reported or high in 30 studies (94%); detection bias was unclear in 31 studies (97%); attrition bias was low in 14 studies (44%), unclear in eight (25%) and high in 12 studies (38%); reporting bias was low in 21 studies (67%) and high in 10 studies (31%); and four studies received industry funding or were terminated early (13%).Steroids lowered risks of progression to ESKD (6 studies, 341 participants: RR 0.44, 95% CI 0.25 to 0.80), and doubling of serum creatinine (6 studies, 341 participants: RR 0.45, 95% CI 0.29 to 0.69), lowered urinary protein excretion (6 studies, 263 participants: MD -0.49 g/24 h, 95% CI -0.72 to -0.25); and preserved glomerular filtration rate (4 studies, 138 participants: MD 17.87 mL/min/1.73 m(2), 95% CI 4.93 to 30.82) compared to no treatment or placebo. Combining steroids plus renin-angiotensin-system (RAS) inhibitors lowered the risk of progression to ESKD (2 studies, 160 participants: RR 0.16, 95% CI 0.04 to 0.59) and reduced urinary protein excretion (1 study, 38 participants: MD -0.20 g/24 h, 95% CI -0.26 to -0.14) compared with RAS inhibitors or steroids alone. Cytotoxic agents (azathioprine) plus steroid regimens plus dipyridamole increased remission of proteinuria (1 study, 78 participants: RR 1.24, 95% CI 1.01 to 1.52) compared to steroids alone but had uncertain effects on other outcomes.Mycophenolate mofetil plus RAS inhibitors lowered the risk of progression to ESKD (1 study, 40 participants: RR 0.22, 95% CI 0.05 to 0.90), improved remission of proteinuria (1 study, 40 participants: RR 2.67, 95% CI 1.32 to 5.39) and reduced urinary protein excretion (1 study, 40 participants: MD -1.26 g/24 h, 95% CI -1.46 to -1.06). Effects of other immunosuppressive regimens (including cyclosporin, leflunomide) were inconclusive primarily due to insufficient data from the individual studies. Subgroup analyses to determine the impact of patient characteristics on treatment effectiveness were not possible.

AUTHORS' CONCLUSIONS

The optimal management of IgAN remains uncertain although corticosteroid therapy may lower the risks of kidney disease progression and need for dialysis or transplantation. Evidence for treatment effects of immunosuppressive agents on mortality, infection, and cancer is generally sparse or low-quality and insufficient to guide clinical practice. Available RCTs are few, small, have high risk of bias - particularly selective reporting - and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible. Larger placebo-controlled studies of corticosteroid therapy or mycophenolate mofetil which are sufficiently powered to evaluate patient-relevant end points including adverse events and that examine the optimal duration of treatment are now required in populations with IgAN with a range of kidney function.

Potential Reparative Role of Resident Adult Renal Stem/Progenitor Cells in Acute Kidney Injury

Human kidney is particularly susceptible to ischemia and toxins with consequential tubular necrosis and activation of inflammatory processes. This process can lead to the acute renal injury, and even if the kidney has a great capacity for regeneration after tubular damage, in several circumstances, the normal renal repair program may not be sufficient to achieve a successful regeneration. Resident adult renal stem/progenitor cells could participate in this repair process and have the potentiality to enhance the renal regenerative mechanism. This could be achieved both directly, by means of their capacity to differentiate and integrate into the renal tissues, and by means of paracrine factors able to induce or improve the renal repair or regeneration. Recent genetic fate-tracing studies indicated that tubular damage is instead repaired by proliferative duplication of epithelial cells, acquiring a transient progenitor phenotype and by fate-restricted clonal cell progeny emerging from different nephron segments. In this review, we discuss about the properties and the reparative characteristics of high regenerative CD133(+)/CD24(+) cells, with a view to a future application of these cells for the treatment of acute renal injury.

Clinical decision support system for end-stage kidney disease risk estimation in IgA nephropathy patients

BACKGROUND

The progression of IgA nephropathy (IgAN) to end-stage kidney disease (ESKD) depends on several factors that are not quite clear and tangle the risk assessment. We aimed at developing a clinical decision support system (CDSS) for a quantitative risk assessment of ESKD and its timing using available clinical data at the time of renal biopsy.

METHODS

We included a total of 1040 biopsy-proven IgAN patients with long-term follow-up from Italy (N = 546), Norway (N = 441) and Japan (N = 53). Of these, 241 patients reached ESKD: 104 Italian [median time to ESKD = 5 (3-9) years], 134 Norwegian [median time to ESKD = 6 (2-11) years] and 3 Japanese [median time to ESKD = 3 (2-12) years]. We independently trained and validated two cooperating artificial neural networks (ANNs) for predicting first the ESKD status and then the time to ESKD (defined as three categories: ≤ 3 years, between > 3 and 8 years and over 8 years). As inputs we used gender, age, histological grading, serum creatinine, 24-h proteinuria and hypertension at the time of renal biopsy.

RESULTS

The ANNs demonstrated high performance for both the prediction of ESKD (with an AUC of 89.9, 93.3 and 100% in the Italian, Norwegian and Japanese IgAN population, respectively) and its timing (f-measure of 90.7% in the cohort from Italy and 70.8% in the one from Norway). We embedded the two ANNs in a CDSS available online (www.igan.net). Entering the clinical parameters at the time of renal biopsy, the CDSS returns as output the estimated risk and timing of ESKD for the patient.

CONCLUSIONS

This CDSS provides useful additional information for identifying 'high-risk' IgAN patients and may help stratify them in the context of a personalized medicine approach.