Histology for nephrology, from pre-implantation to post-transplant kidney biopsy. Lesson learned from ReBIrth (Renal BIopsy for Kidney Transplantation Therapy).

A meeting entitled Renal BIopsy for Kidney Transplantation Therapy (ReBIrth) took place on May 31st, 2022 in Bologna, Italy. The meeting drew together nephrologists, surgeons, and pathologists and recognized as experts in the field of kidney transplantation in Italy. In this paper, we present our experience working with kidney transplants in the current era of immunosuppression therapy. The primary aim is to report the histopathological characteristics of failed kidney allografts after a consensus of experts reviewed the cases on a wholeslide imaging digital platform. Regardless of the cases discussed, digital pathology was reliable in identifying all the morphological and immunohistochemical features required to improve the correct use of immunosuppressive therapy to prevent graft failure and optimize patient management.

Intraperitoneal Pressure in Polycystic and Non-Polycystic Kidney Disease Patients, Treated by Peritoneal Dialysis.

INTRODUCTION: Intraperitoneal volume (IPV) should be individualized and aimed to maintain an intraperitoneal pressure (IPP) lower than 17 cm H2O. IPP is very variable, given its relation with body size. However, it is not yet fully understood which anthropometric variable mostly affects IPP and the relation between IPP and organomegaly in polycystic kidney disease (PKD) patients is not known. OBJECTIVES: The aim of the present study was to analyse the relation between antropometric variables and IPP in a large cohort of peritoneal dialysis (PD) patients and to identify if a relation between nephromegaly and IPP exists in PKD patients. METHODS: IPP was measured in PD patients and data was retrospectively collected. In PKD patients, total kidney volumes were measured in CT scans, and normalized with height (hTKV). RESULTS: Seventy-seven patients were included in the study, 18% affected by PKD. Mean IPP was 14.9 ± 2.9 cm H2O and it showed significant positive correlation with body mass index (BMI; ρ = 0.42, p < 0.001). No correlation was found between IPP and absolute IPV; conversely, IPP has a significant inverse correlation with IPV normalized with BMI and body surface area (ρ -0.38, p = 0.001 and ρ -0.25, p = 0.02, -respectively). Patients with IPP >17 cm H2O have significant larger BMI and lower IPV/BMI compared to those with IPP <17 cm H2O (29 ± 3.6 vs. 26 ± 4 kg/m2, p < 0.05 and 97 ± 15.5 vs. 109 ± 22 mL/kg/m2, p < 0.05). PKD patients have a wide variability in hTKV (range 645-3,787 mL/m2) and it showed a significant correlation with IPP/IPV (ρ = 0.6, p < 0.05). CONCLUSIONS: Patients with larger BMI have greater IPP, irrespectively to IPV. In PKD patients, hTKV correlate with IPP/IPV ratio. However, given the wide range of distribution of hTKV, increased IPP cannot be presumed because of pre-existing polycystic kidney, but need to be quantified.

Brief Review and a Clinical Case of Hemolytic Uremic Syndrome Associated with Interferon ß Treatment.

The hemolytic uremic syndrome (HUS) is one of the thrombotic microangiopathies and it consists of the triad of nonimmune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The atypical form of HUS (aHUS) is related to causative mutations in complement genes. Some conditions act as a trigger for aHUS in individuals that have a genetic background predisposing to complement activation. Interferon ß is a recombinant-protein therapy approved to treat multiple sclerosis (MS), and can be a causative agent in the occurrence of HUS through anti-angiogenic activity. In this paper, we briefly review aHUS clinical and genetic characteristics. Furthermore, we present a case of a 48-year-old woman, diagnosed with MS and treated with INFß-1b from 2008. In December 2015, she presented with asthenia and loss of muscular strength in the legs and she quickly developed aHUS. Our case suggests that INFß is a possible triggering factor for HUS.

Copeptin levels and kidney function in ADPKD: case-control study.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. Studies have suggested a possible prognostic role of copeptin in determining the rate of progressive kidney function decline in ADPKD patients. However, it remains unresolved whether the changes in copeptin levels are specific for ADPKD or merely reflect a decline in glomerular filtration rate (GFR) regardless of the etiology of chronic kidney disease (CKD). METHODS: We performed a case-control study in ADPKD and non-ADPKD (control) patients. Patients were categorized based on the GFR-category (G-stage, KDIGO). We evaluated urea, creatinine, cystatin C, and copeptin in plasma and correlated these levels with estimated glomerular filtration rate (eGFR) (CKD-EPI). All p-values were two sided, and p < 0.05 was considered as statistically significant. RESULTS: We enrolled 112 ADPKD and 112 control patients. The median copeptin level was 10.72 (interquartile range (IQR) 5.21 - 26.21) pmol/L in the ADPKD group and 12.32 (IQR 4.47 - 30.73) pmol/L in the control group. The median copeptin level increased according to the G-stage in a progressive fashion and remained statistically significant across all G-stages and in both groups. Copeptin levels were not significantly different between ADPKD and control groups. We found a significant inverse correlation between copeptin level and eGFR (Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)) in the ADPKD, r = -0.81 (p < 0.001), and in the control group, r = -0.76 (p < 0.001). CONCLUSIONS: Copeptin levels seem to be strongly correlated with renal function rather than the presence of ADPKD. Further prospective studies need to evaluate its role as a prognostic marker in the early stage of CKD for ADPKD progression.

High-resolution melt as a screening method in autosomal dominant polycystic kidney disease (ADPKD).

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is an inherited condition caused by PKD1 and PKD2 mutations. Complete analysis of both genes is typically required in each patient. In this study, we explored the utility of High-Resolution Melt (HRM) as a tool for mutation analysis of the PKD2 gene in ADPKD families. METHODS: HRM is a mismatch-detection method based on the difference of fluorescence absorbance behavior during the melting of the DNA double strand to denatured single strands in a mutant sample as compared to a reference control. Our families were previously screened by linkage analysis. Subsequently, HRM was used to characterize PKD2-linked families. Amplicons that produced an overlapping profile sample versus wild-type control were not further evaluated, while those amplicons with profile deviated from the control were consequently sequenced. RESULTS: We analyzed 16 PKD2-linked families by HRM analysis. We observed ten different variations: six single-nucleotide polymorphisms and four mutations. The mutations detected by HRM and confirmed by sequencing were as follows: 1158T>A, 2159delA, 2224C>T, and 2533C>T. In particular, the same haplotype block and nonsense mutation 2533C>T was found in 8 of 16 families, so we suggested the presence of a founder effect in our province. CONCLUSIONS: We have developed a strategy for rapid mutation analysis of the PKD2 gene in ADPKD families, which utilizes an HRM-based prescreening followed by direct sequencing of amplicons with abnormal profiles. This is a simple and good technique for PKD2 genotyping and may significantly reduce the time and cost for diagnosis in ADPKD.

Using machine learning to predict antibody response to SARS-CoV-2 vaccination in solid organ transplant recipients: the multicentre ORCHESTRA cohort.

OBJECTIVES: The study aim was to assess predictors of negative antibody response (AbR) in solid organ transplant (SOT) recipients after the first booster of SARS-CoV-2 vaccination. METHODS: Solid organ transplant recipients receiving SARS-CoV-2 vaccination were prospectively enrolled (March 2021-January 2022) at six hospitals in Italy and Spain. AbR was assessed at first dose (t0), second dose (t1), 3 ± 1 month (t2), and 1 month after third dose (t3). Negative AbR at t3 was defined as an anti-receptor binding domain titre <45 BAU/mL. Machine learning models were developed to predict the individual risk of negative (vs. positive) AbR using age, type of transplant, time between transplant and vaccination, immunosuppressive drugs, type of vaccine, and graft function as covariates, subsequently assessed using a validation cohort. RESULTS: Overall, 1615 SOT recipients (1072 [66.3%] males; mean age±standard deviation [SD], 57.85 ± 13.77) were enrolled, and 1211 received three vaccination doses. Negative AbR rate decreased from 93.66% (886/946) to 21.90% (202/923) from t0 to t3. Univariate analysis showed that older patients (mean age, 60.21 ± 11.51 vs. 58.11 ± 13.08), anti-metabolites (57.9% vs. 35.1%), steroids (52.9% vs. 38.5%), recent transplantation (<3 years) (17.8% vs. 2.3%), and kidney, heart, or lung compared with liver transplantation (25%, 31.8%, 30.4% vs. 5.5%) had a higher likelihood of negative AbR. Machine learning (ML) algorithms showing best prediction performance were logistic regression (precision-recall curve-PRAUC mean 0.37 [95%CI 0.36-0.39]) and k-Nearest Neighbours (PRAUC 0.36 [0.35-0.37]). DISCUSSION: Almost a quarter of SOT recipients showed negative AbR after first booster dosage. Unfortunately, clinical information cannot efficiently predict negative AbR even with ML algorithms.

[Lymphocytic leukopenia in two patients affected by polycystic kidney disease waiting for renal transplantation].

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, responsible for 10% of patients on renal replacement therapy. The disease is well known to be associated with many extrarenal manifestations. Leukopenia may also be present, even if it is not commonly identified as a typical extrarenal manifestation. Herein we describe two case reports of ADPKD patients with leukopenia. The first case is about a 47-year-old patient affected by ADPKD, regularly treated with peritoneal dialysis, who showed a progressive reduction of white blood cell count, mostly of lymphocytes. Lymphocytic leukopenia was so severe that, when he was called for transplantation from a deceased donor, he was considered temporarily not eligible. We then describe a second ADPKD patient regularly treated with peritoneal dialysis, who had stable lymphopenia for years. Six years after starting PD, it was necessary to perform bone marrow aspirate to investigate the simultaneous presence of hypogammaglobulinemia together with M-protein and to exclude monoclonal gammopathy. All the exams performed did not show any significant results, the patients were re-included in the waiting list and one of them was transplanted. Given our experience and what is reported in the literature, there seems to be enough evidence to consider leukopenia as an extrarenal manifestation of ADPKD. However, the clinical significance of leukopenia in ADPKD patients is not known. It could be interesting to investigate the leucocytes' function and if ADPKD patients with leukopenia are more susceptible to infection, or not. Moreover, it would be very useful to analyze the relationship between such manifestation and genotype/phenotype.

Evaluation of the Kinetics of Antibody Response to COVID-19 Vaccine in Solid Organ Transplant Recipients: The Prospective Multicenter ORCHESTRA Cohort.

Previous studies assessing the antibody response (AbR) to mRNA COVID-19 vaccines in solid organ transplant (SOT) recipients are limited by short follow-up, hampering the analysis of AbR kinetics. We present the ORCHESTRA SOT recipients cohort assessed for AbR at first dose (t0), second dose (t1), and within 3 ± 1 month (t2) after the first dose. We analyzed 1062 SOT patients (kidney, 63.7%; liver, 17.4%; heart, 16.7%; and lung, 2.5%) and 5045 health care workers (HCWs). The AbR rates in the SOTs and HCWs were 52.3% and 99.4%. The antibody levels were significantly higher in the HCWs than in the SOTs (p < 0.001). The kinetics showed an increase (p < 0.001) in antibody levels up to 76 days and a non-significant decrease after 118 days in the SOT recipients versus a decrease up to 76 days (p = 0.02) and a less pronounced decrease between 76 and 118 days (p = 0.04) in the HCWs. Upon multivariable analysis, liver transplant, ≥3 years from SOT, mRNA-1273, azathioprine, and longer time from t0 were associated with a positive AbR at t2. Older age, other comorbidities, mycophenolate, steroids, and impaired graft function were associated with lower AbR probability. Our results may be useful to optimize strategies of immune monitoring after COVID-19 vaccination and indications regarding timing for booster dosages calibrated on SOT patients' characteristics.

[Slowing progression of chronic kidney disease in polycistic kidney disease patients with tolvaptan: from guidelines to clinical practice].

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and accounts for∼10% of patients on renal replacement therapy. In the last decade, no specific treatment was available and only preventive measures could be put in place to delay the onset of ESRD. Following the results of the TEMPO 3:4 study, tolvaptan was approved in many countries, for the purpose of slowing the progression of renal insufficiency. In Italy tolvaptan is available since 2016 for patients with chronic kidney disease (CKD) stage 1-3, and since 2020 for patients with CKD stage 4, who fulfil the criteria of "rapid disease progression", according to the European recommendations. After this approval, Italian nephrology units have had to change their organization to be able to identify the patients eligible for the drug and to guarantee frequent patient monitoring. In this paper, we present our three-year experiences with tolvaptan, focusing on its safety profile and tolerability, but also on the high burden of care that such therapy represents not only for doctors, but also for patients. Strategies to implement remote monitoring may be useful to reduce the burden of assistance on one side, and the medicalization of ADPKD patients in the early stage of the disease, on the other.

[Epidemiological and molecular study of autosomal dominant polycystic kidney disease (ADPKD) in the province of Vicenza, Italy: possible founder effect?]. / Studio epidemiologico e molecolare sulla malattia autosomica dominante del rene policistico (ADPKD) nella provincia di Vicenza: possibile effetto fondatore?

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic renal disorder, with a prevalence of 1:400 to 1:1000. ADPKD is genetically and clinically heterogeneous. In addition, significant intrafamilial renal disease variability is evident. The prevalence of ADPKD patients on renal replacement therapy in Italy has been reported to be 8.2%. In the dialysis population of Vicenza province (northeast Italy), in one area especially, ADPKD cases account for 13.4%. We hypothesize that this high frequency is related to a founder effect in this geographically isolated population. Since April 2007 we have studied the characteristics of ADPKD patients and the presence of haplotypes shared by several families. The clinical profile of patients in the Vicenza province is similar to that described in the literature but there is a high prevalence of ADPKD in several isolated areas. These areas are characterized by the presence of three distinct haplotypes, suggesting a strong lineage-specific gene.

Predictors of rapid disease progression in autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases with a reported prevalence of 1:400 to 1:1000. Since the intact kidneys can compensate for the loss of glomerular filtration in ADPKD patients, renal insufficiency usually remains undetected until almost the fourth decade of life. Hereafter, reliable diagnostic and prognostic biomarkers to identify ADPKD progression are urgently needed. Several studies and systematic reviews tried to identify markers or predictors of rapid disease progression of ADPKD. The aim of this study is to review predictors of rapid disease progression of ADPKD that can be useful to the clinician. We will describe several factors associated with rapid progression of ADPKD derived from retrospective or cross-sectional studies, suggesting the best and most useful predictors that may help to patients management in clinical practice. We will attempt to identify the most useful predictors of rapid disease progression of ADPKD: established TKV growth rate >5% per year, annual estimated glomerular filtration rate decline >5 mL/min/1.73 m2, truncating PKD1 mutations and elevated plasma copeptin level. The combination of several factors that can predict the rapid ADPKD progression is more accurate than a single-marker strategy. The "PRO-PKD" risk scoring system combined with TKV, can be useful in order to evaluate the ADPKD patients and they appear to be appropriate predictors of progression disease. Moreover levels of copeptin and some urinary markers can be matched to these factors for improved patient assessment in rapid progression.

Genetics and Autosomal Dominant Polycystic Kidney Disease Progression.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, accounting for 10% of European patients on renal replacement therapy. In the previous years, many approaches to slow the progression of ADPKD were studied and many clinical trials published. In addition to having diagnostic role, the description of the genotype is even important to predict the progression of the disease and contributes, combined with several other factors, to a more precise patients classification. With the availability of disease-modifying drugs, "fast progression factors" are needed to early recognize those patients who would likely progress, before cyst growth reaches a critical value. ERA-EDTA working group on inherited kidney disorders included a series of recommendations resulting in a hierarchical decision algorithm to select patients who are most likely to benefit from the treatment. Beyond diagnosis, we will also discuss the important role of genetics in ADPKD progression and management.

[Plasma NGAL and ADPKD progression]. / Ruolo di NGAL nella progressione dell'insufficienza renale determinata da ADPKD.

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease with variable rate of progression. It is associated with inter- and intra-familial variability. Neutrophil gelatinase-associated lipocalin (NGAL) has been implicated in pathological conditions and it is proposed as a biomarker for CKD progression. Our aim was to evaluate whether NGAL could be a good marker for progression of ADPKD, as we hypothesized. ADPKD patients with confirmed mutations (PKD1 n=33; PKD2 n=17) were enrolled and followed in a prospective study. Creatinine (sCr) and NGAL values were measured at baseline and on follow-up. Plasma NGAL was measured by Triage point of care test. CKD progression was defined as 15% decrease in eGFR from baseline to follow-up. Patients were divided into 2 groups based on median baseline NGAL and compared by the Kaplan-Meier curve. We enrolled 50 ADPKD pts (60%M age 41 yrs); mean sCr 1.30.7 mg/dl and median eGFR was 62 mL/min/1.73 m2. NGAL values are inversely correlated with baseline eGFR (r=-0.64, p<0.001). There was weak correlation between baseline NGAL and subsequent change in eGFR (r=0.28, p=0.05). 9/50 of patients had NGAL below limits of detection (60 pg/ml); median NGAL level was 79 pg/ml. At follow-up, 12 patients (24%) had progression as defined. No statistically significant relationship between higher NGAL and ADPKD progression was observed. We did not observe a relationship between NGAL and CKD progression in ADPKD patients; however 18% of patients had undetectable plasma NGAL levels. This raises doubt about the utility of the current NGAL assay as a biomarker for CKD progression in this population.

Erythropoeitin dose variation in different facilities in different countries and its relationship to drug resistance.

BACKGROUND: The correction of anemia using erythropoeitin (EPO) is accorded high priority in the management of patients undergoing hemodialysis (HD). Target hemoglobin (Hb) levels have been established in many countries. Following an observation that the mean facility EPO dose in a chain of facilities in the United States varied by more than two-fold, an examination of the practice of anemia correction in other settings was carried out. METHODS: We reviewed demographic and laboratory parameters in prevalent HD patients in 50 United States facilities and in a single HD facility in Vicenza, Italy. The mean EPO dose profile of the United States facilities was compared with the profiles in 10 facilities in the eastern United Kingdom (UKER) and in 20 facilities reporting to the United Kingdom Renal Registry (UKRR). Analysis of the factors that correlate with EPO resistance was carried out using the United States and Italian data. RESULTS: The average EPO doses, by facility, in the 51 United States, the 10 UKER, and the 19 UKRR facilities were 19,569, 8,416, and 7,992 international units per week (IU/wk), respectively. While examination of the UKRR revealed a similar degree of inter-facility variation (2.6-fold), much larger doses of EPO were being administered in the United States patients, particularly in the low Hb group. Multivariate analysis of the United States data suggested that factors related to inflammation, including low albumin, the use of tunneled catheters for vascular access, and low protein catabolic rate (enPCR) correlated with low Hb and relative EPO resistance. CONCLUSION: Despite similar guidelines for anemia management, significant differences in practice are observed. While there seems to be a reluctance to administer large EPO doses to individual patients in Europe, this does not seem to apply in the United States, where more EPO is given. EPO resistance seems relative rather than absolute in many patients, allowing some to respond to the higher doses.

[Genotype-phenotype correlation in ADPKD: a possible role for NGAL?]. / Correlazione Genotipo-Fenotipo in ADPKD: possibilie utilità di NGAL?

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic cause of chronic kidney disease (CKD) in adults. It is associated with both inter- and intra- familial variability, which can be explained by genetic heterogeneity, modifier genes and a genetic background. NGAL, a 25-kDa protein released from tubular cells after harmful stimuli, is a new biomarker. Recent studies suggest a possible role for NGAL in CKD. The aim of this study was to investigate NGAL in the context of genotype-phenotype correlation in ADPKD. METHODS: We measured plasma NGAL, creatinine (Cr), and urea in 18 ADPKD patients on dialysis (PKD1_TRS), 29 of their relatives with CKD stage II-III (PKD1_AMB), 33 wild-type relatives (PKD1_WT), 12 subjects in CKD stage II-III with confirmed mutation in PKD2 and 30 healthy controls (CTR). Cr, urea and CysC were measured according to standard methods. Plasma NGAL was measured using point-of-care test. Estimated glomerular filtration rate (eGFR) was calculated with a 4-variable standardized-MDRD formula. RESULTS: Plasma NGAL, CysC, Cr and urea levels in PKD1_TRS were significantly higher than CTR (all with p<0,001). PKD1_TRS pts had significantly higher NGAL, CysC, Cr and Urea levels compared to PKD1_AMB and PKD1_WT. PKD1_AMB pts had higher NGAL, CysC, Urea and Cr levels compared to PKD1_WT relatives. NGAL CysC, Cr and urea values were similar between PKD1_WT and CTR (p>0.05). NGAL levels were not significantly different in ADPKD patients in CKD stage II-III with mutation in PKD1 or PKD2 (86 pg/mL, IQR 60-109 vs 82 pg/mL,IQR 63-169). NGAL correlated well (all with p<0.001) with CysC (r=0.95), Cr (r=0.89), urea (r=0.76) and inversely with eGFR (r=-0.81). A strong correlation between CysC and residual renal function was observed (CysC/eGFR: r=-0.86; CysC/Cr: r=0.7; CysC/Urea: r=0.79, all with p<0.001). CONCLUSION: This is the first study to evaluate plasma NGAL in the context of genotype-phenotype correlation. In ADPKD, NGAL levels were higher in patients already on Renal Replacement Therapy (RRT) compared to their affected relatives not on RRT. WT relatives had normal NGAL and CysC levels: these could be considered a better CTR group because they share the same genetic background with ADPKD subjects. No differences were found in NGAL levels between PKD1 and PKD2 patients in CKD stage II-III. Furthermore, the results indicate that NGAL correlates closely with renal function and CysC levels.

ADPKD: Prototype of Cardiorenal Syndrome Type 4.

The cardiorenal syndrome type 4 (Chronic Renocardiac Syndrome) is characterized by a condition of primary chronic kidney disease (CKD) that leads to an impairment of the cardiac function, ventricular hypertrophy, diastolic dysfunction, and/or increased risk of adverse cardiovascular events. Clinically, it is very difficult to distinguish between CRS type 2 (Chronic Cardiorenal Syndrome) and CRS type 4 (Chronic Renocardiac Syndrome) because often it is not clear whether the primary cause of the syndrome depends on the heart or the kidney. Autosomal dominant polycystic kidney disease (ADPKD), a genetic disease that causes CKD, could be viewed as an ideal prototype of CRS type 4 because it is certain that the primary cause of cardiorenal syndrome is the kidney disease. In this paper, we will briefly review the epidemiology of ADPKD, conventional and novel biomarkers which may be useful in following the disease process, and prevention and treatment strategies.

Monocyte apoptosis in uremia is normalized with continuous blood purification modalities.

Uremia is associated with a state of immune dysfunction. Dysregulation of homeostasis may be directly related to abnormal apoptosis regulation in uremia, which is crucial for the maintenance of the biological system. We demonstrated that plasma from three groups of uremic subjects, i.e. hemodialysis (HD) patients, peritoneal dialysis (PD) patients and patients with predialysis chronic renal failure (CRF), has different apoptotic potential on U937 monocytes. The plasma of HD and CRF subjects when incubated with U937 cells induced higher levels of apoptosis compared with that of PD and control subjects (HD 26.08 +/- 11.39, CRF 24.87 +/- 9.07, PD 12.13 +/- 4.51, controls 11.69 +/- 4.02). Furthermore, the phagocytic ability of U937 cells incubated with the various plasma demonstrated an impaired response in the HD and CRF subjects (HD 27.56 +/- 6.67, CRF 30.24 +/- 9.08, PD 36.55 +/- 9.80, controls 40.04 +/- 6.98). These results suggest that continuous blood purification, such as in PD, may have advantages over intermittent therapies in removing uremic apoptotic molecules and potentially maintaining biological function and homeostasis.