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Purpose of review: This short review is intended to highlight the potential role of inflammation as a key pathological driver, rather than a mere consequence, of nephrolithiasis. Although there is clearly a strong likelihood that the relationship is bidirectional, and that kidney stone-triggered inflammation can establish a vicious cycle of tissue injury and stone formation. Recent findings: These consist of data from both recent preclinical and clinical studies demonstrating the importance of inflammation in models of stone disease and in kidney tissue from patients with nephrolithiasis, and as a potential driver of disease recurrence and a suitable treatment target. In particular, the role of immune cells and their relationship to the NLRP3 inflammasome is becoming clearer, as well as the potential contribution to tissue injury and stone formation of the pro-inflammatory cytokines interleukin-1β and interleukin-18. Summary: This concept is not new and raises the possibility that targeting inflammation directly may prove to be a novel and suitable means of treatment for at least some types of kidney stone, and in certain clinical settings, both acutely and as prevention, especially in those patients experiencing recurrent stone episodes and/or who have a well defined metabolic cause such as uric acid or calcium oxalate stones.

BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is associated with significant risk of forming kidney stones, especially those made of calcium oxalate and uric acid, compared with the general population. Since crystals are able to activate the inflammasome and lead to cell injury, crystalluria might worsen ADPKD natural history, acting as a third hit. METHODS The Bern ADPKD registry is a prospective observational cohort study. Height-adjusted total kidney volume (ht-TKV) was measured at baseline and every 3 years. Twenty-four hour urinary solute excretions collected at baseline and eGFR measurements over time were included in this analysis. Twenty-four hour urinary supersaturations (SS) for calcium oxalate, calcium phosphate and uric acid were calculated using EQUIL-2. Linear regression models were used to assess linear and non-linear associations between slopes of ht-TKV and eGFR with SSs and 24 h urinary solute excretions. RESULTS Seventy-seven participants (mean age 45.0 [SD 12.9] years, eGFR 76.4 [28.3] mL/min/1.73 m2) were included, with a median follow-up of 4 years. The median slopes of ht-TKV and eGFR were 3.9 percent/year and 2.9 mL/min/1.73 m2/year, respectively. SS for uric acid showed a direct, linear association (p value for linearity 0.035) with ht-TKV slope. When analyzing individual components, urinary uric acid, ammonium, magnesium and sulfate were all directly associated with ht-TKV slope. Urinary sulfate was also directly associated with eGFR slope. CONCLUSIONS Uric acid supersaturation and several other urinary components are identified as predictors of cyst growth in patients with ADPKD. Future studies with a dedicated design are needed to investigate the pathophysiological mechanisms underlying these associations.

BackgroundAnti-PCSK9 monoclonal antibodies are effective in reducing LDL-C and cardiovascular events by neutralizing circulating PCSK9. PCSK9, however, is also expressed in tissues, including the pancreas, and studies on PCSK9 KO mice have shown impaired insulin secretion. Statin treatment is already known to affect insulin secretion. Our aim was to conduct a pilot study to evaluate the effect of anti-PCSK9 mAb on glucose metabolism and β-cell function in humans.MethodsFifteen non-diabetic subjects, candidates for anti-PCSK9 mAb therapy, were enrolled. All underwent OGTT at baseline and after 6 months of therapy. During OGTT, insulin secretion parameters were derived from C-peptide by deconvolution (β cell glucose sensitivity). Surrogate insulin sensitivity indices were also obtained from OGTT (Matsuda).ResultsGlucose levels during OGTT were unchanged after 6 months of anti-PCSK9 mAb treatment, as well as insulin and C-peptide levels. The Matsuda index remained unchanged, while β-cell glucose sensitivity improved post-therapy (before: 85.3 ± 65.4; after: 118.6 ± 70.9 pmol min-1m-2mM-1; p2) and found that those with higher BMI had a greater increase in βCGS after therapy (before: 85.37 ± 24.73; after: 118.62 ± 26.83 pmol min-1m-2mM-1; p=0.007). There was also a significant correlation between βCGS change and Matsuda index through linear regression (p=0.04), so we analyzed subjects who had values above and below the median (3.8). This subgroup analysis showed a slight though not significant improvement in βCGS in more insulin resistant patients, (before: 131.4 ± 69.8; after: 170.8 ± 92.7 pmol min-1m-2mM-1; p=0.066).ConclusionsOur pilot study demonstrates that six-month treatment with anti-PCSK9 mAb improves β-cell function, and does not alter glucose tolerance. This improvement is more evident in patients with greater insulin-resistance (low Matsuda) and higher BMI.

Additional file 1: TableS1 Baseline features of continuous variables of the study population. Table S2 Baseline biochemical and metabolic parameters of the diabetic population. Table S3 Bivariate correlations of several variables in the study population. Fig.S1 Relationship between KIM-1 with UfRBP4 and Ualb across all study groups. KIM-1: Kidney injury molecule 1 (ng/mL); UfRBP4: urine free retinol-binding protein 4 (ug/mmol); Ualb: urinary albumin expressed as albumin to creatinine ratio (mg/mmol).

Additional file 1. SUPPLEMENTARY DATA

Transition in medical care is a high-risk period in adolescence and young adulthood. To date, data on transition policy, its application in practice, and transition procedures in patients with rare, hereditary kidney diseases in Europe is scarce. An online survey was developed and was distributed within the paediatric centres of the European Reference Network for Rare Kidney Diseases (ERKNet) aiming to assess the transition-relevant structures from the providers' perspectives. Its items were based on the consensus statement on transition published by the International Society of Nephrology (ISN) and the International Paediatric Nephrology Association (IPNA) in 2011. Forty-six paediatric experts based at 28/32 ERKNet university hospitals participated. Annually, a median number of 14 patients (1-80) are transferred to adult based care. One centre continued to care for paediatric kidney transplant recipients throughout their entire lifespan. Choosing this option terminated the survey and no further data was obtained from this centre. 29/45 experts confirmed the application of an-at least unwritten-transition procedure (64%). Transition clinics are offered by 23 experts. Most physicians (40%) transfer patients at age 18-19, 10 experts at age

Despite being recommended by most guidelines, the metabolic evaluation of patients with nephrolithiasis has limited diffusion due to difficulties relating both to the access to laboratory investigations and to urine collection modalities. Consequently, in addition to the classical 24-h collection, alternative and simplified collection modes have been proposed. We report here on the comparison between metabolic evaluation carried out on 24-h double collection (Lithotest) and overnight spot urines (RF test). Fifty-four patients with stone disease were enrolled, excluding patients with infection or cystine stones. For Lithotest, we measured all analytes necessary to calculate state of saturation (ß) with calcium oxalate, brushite and uric acid, by means of Lithorisk.com. For RF, we measured calcium, magnesium, oxalate, citrate, sulphate, phosphate, pH and creatinine. The comparison was made with creatinine ratios. An estimate of ßCaOx, ßbrushite and ßAU was obtained also on RF urines by using simplified algorithms. We found highly significant correlations between all parameters, despite quite different means. There was a nice correspondence between the two sets of measurements, assessed by the Bland-Altmann test, for calcium, oxalate, citrate, sulphate, urate and pH. Overnight urine had higher saturations compared to 24-h one owing to higher concentration of the former. In conclusion, RF test on overnight urine cannot completely replace Lithotest on 24-hr urine. However, it can represent a simplified tool for either preliminary evaluation or follow-up of patients with stone disease.

Additional file 2: Table S2. List of key performance and outcome indicators (KPIs) in ERKReg Registry

Additional file 1: Table S1. Association between AKI and seasons. Supplementary Table 2. Association between AKI and seasons, stratified analysis by age and sex

Subjects with the rare autosomal dominant disease Hereditary Hemorrhagic Telangiectasia (HHT) may develop medical conditions that require antithrombotic therapy (AT). However, safety of AT is uncertain in these patients and the only data currently available derive from retrospective analyses of registries and/or databases. At the HHT Centre of the ‘Fondazione Policlinico Universitario A. Gemelli IRCCS’ (Rome, Italy), a prospective study is currently ongoing to evaluate the safety of AT in subjects affected by HHT. The study is enrolling subjects with a definite diagnosis of HHT who receive an AT prescription by one of the physicians of the HHT Centre. The primary outcome is the number of hemorrhagic events, distinguished in major, clinically relevant non-major (CRNM), and minor bleedings, according to the criteria of the International Society on Thrombosis and Hemostasis (ISTH). Another primary outcome is worsening of epistaxis upon initiation of AT, assessed using the internationally accepted Epistaxis Severity Score (ESS). Additional outcomes are changes in hemoglobin levels and changes in the need of blood transfusion after initiation of AT. Here, we present the results of an interim analysis, conducted on the 12 HHT subjects that have been enrolled so far. After a mean follow-up of 6.5 ± 0.8 months, no major bleedings, no CRNM bleedings, and no minor bleedings different from epistaxis were recorded. Worsening of epistaxis upon initiation of AT was documented only in one patient, but did not require discontinuation of AT. There were no significant changes in the mean ESS measured before and after initiation of AT. There were no significant changes in hemoglobin levels and need for blood transfusion after initiation of AT. Although preliminary, these are the first prospective data on the safety of AT in HHT patients. Our interim analysis suggests that, when prescribed by experienced physicians in a multidisciplinary setting, AT is well tolerated by HHT patients. More patients and a longer follow-up are needed to confirm these findings.

Renal stone patients are generally considered to be affected with the idiopathic form of calcium nephrolithiasis. It is debated whether a comprehensive diagnostic evaluation should be performed in first stone patients. There is a substantial number of first or mildly recurrent stone formers who do not undergo any work-up to investigate stone etiology and in whom stone etiology is unknown. In this setting, the endourological approach can provide the treating physician with diagnostic information based on the presence of Randall's plaques and/or ductal plugs, thus triggering the need for further clinical investigations.

We review the available literature on granulocyte-monocyte apheresis for the treatment of inflammatory bowel disease and report the outcome data of a multicenter observational study from the Italian registry for therapeutic apheresis.

We analyzed predictors of clinical response after a cycle of granulocytemonocyte apheresis in 173 patients with ulcerative colitis. Hemoglobin levels independently predicted good clinical outcome.

There is currently no consensus about the indications for therapeutic apheresis, also due to the lack of large clinical trials. A registry where all the data can be organized and analyzed therefore becomes a priority for all professionals involved in apheresis. The Apheresis Study Group of the Italian Society of Nephrology has instituted a registry for data collection. This report describes data collected from 1994 to 2008 by 68 units of different specialties in 15 Italian regions. Data about 29,260 treatments on 2,503 patients were recorded. Plasma exchange accounted for 43.4% of the procedures; 37% of these were performed by filtration. Plasma treatment was used in 48% of procedures, in particular with protein A immunoadsorption (11%), LDL-cholesterol apheresis by dextran sulfate adsorption (13%), and semiselective cascade or double filtration (12.5%). Cell apheresis, limited to photopheresis and leukocytapheresis, was used in 3.6% of cases, and whole blood treatment, with different techniques, in 5% of cases for the treatment of dyslipidemia, liver failure and sepsis. These procedures account for about 20% of the estimated therapeutic apheresis performed in Italy according to the national survey performed for the year 2005 by the Italian Apheresis and Cell Manipulation Society. The data collected are sufficiently informative to show a definite trend to use plasma/whole blood treatments as often as possible. The registry not only is a tool for consultation and information, but also a platform to plan and realize interdisciplinary and multicenter clinical trials.

The Consensus Group deliberated on a number of questions concerning urine and stone analysis over a period of months, and then met to develop consensus. The Group concluded that analyses of urine and stones should be routine in the diagnosis and treatment of urinary stone diseases. At present, the 24-h urine is the most useful type of urine collection, and accepted methods for analysis are described. Patient education is also important for obtaining a proper urine sample. Graphical methods for reporting urine analysis results can be helpful both for the physician and for educating the patient as to proper dietary changes that could be beneficial. Proper analysis of stones is also essential for diagnosis and management of patients. The Consensus Group also agreed that research has shown that evaluation of urinary crystals could be very valuable, but the Group also recognizes that existing methods for assessment of crystalluria do not allow this to be part of stone treatment in many places.

Cystinuria is the most common genetic cause of nephrolithiasis in children. It is considered a heritable aminoaciduria as the genetic defect affects the reabsorption of cystine and three other amino acids (ornithine, lysine, and arginine) in the renal proximal tubule. Patients affected by this condition have elevated excretion of cystine in the urine, and because of this amino acid's low solubility at normal urine pH, patients tend to form cystine calculi. To date, two genes have been identified as disease-causative: SLC3A1 and SLC7A9, encoding for the two subunits of the heterodimeric transporter. The clinical features of this condition are solely related to nephrolithiasis. The diagnosis is usually made during infancy or adolescence, but cases of late diagnosis are common. The goal of therapy is to reduce excretion and increase the solubility of cystine, through both modifications of dietary habits and pharmacological treatment. However, therapeutic interventions are not always sufficient, and patients often have to undergo several surgical procedures during their lives to treat recurrent nephrolithiasis. The goal of this literature review is to synthesize the available evidence on diagnosis and management of patients affected by cystinuria in order to provide physicians with a practical tool that can be used in daily clinical practice. This review also aims to shed some light on new therapy directions with the aim of ameliorating kidney outcomes while improving adherence to treatment and quality of life of cystinuric patients.