Immune checkpoint inhibitors induce acute interstitial nephritis in mice with increased urinary MCP1 and PD-1 glomerular expression.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) induce acute interstitial nephritis (AIN) in 2-5% of patients, with a clearly higher incidence when they are combined with platinum derivatives. Unfortunately, suitable disease models and non-invasive biomarkers are lacking. To fill this gap in our understanding, we investigated the renal effects of cisplatin and anti-PD-L1 antibodies in mice, assessing PD-1 renal expression and cytokine levels in mice with AIN, and then we compared these findings with those in AIN-diagnosed cancer patients. METHODS: Twenty C57BL6J mice received 200 µg of anti-PD-L1 antibody and 5 mg/kg cisplatin intraperitoneally and were compared with those receiving cisplatin (n = 6), anti-PD-L1 (n = 7), or saline (n = 6). After 7 days, the mice were euthanized. Serum and urinary concentrations of TNFα, CXCL10, IL-6, and MCP-1 were measured by Luminex. The kidney sections were stained to determine PD-1 tissue expression. Thirty-nine cancer patients with AKI were enrolled (AIN n = 33, acute tubular necrosis (ATN) n = 6), urine MCP-1 (uMCP-1) was measured, and kidney sections were stained to assess PD-1 expression. RESULTS: Cisplatin and anti PD-L1 treatment led to 40% AIN development (p = 0.03) in mice, accompanied by elevated serum creatinine and uMCP1. AIN-diagnosed cancer patients also had higher uMCP1 levels than ATN-diagnosed patients, confirming our previous findings. Mice with AIN exhibited interstitial PD-1 staining and stronger glomerular PD-1 expression, especially with combination treatment. Conversely, human AIN patients only showed interstitial PD-1 positivity. CONCLUSIONS: Only mice receiving cisplatin and anti-PDL1 concomitantly developed AIN, accompanied with a more severe kidney injury. AIN induced by this drug combination was linked to elevated uMCP1, consistently with human AIN, suggesting that uMCP1 can be potentially used as an AIN biomarker.

Tools for a personalized tacrolimus dose adjustment in the follow-up of renal transplant recipients. Metabolizing phenotype according to CYP3A genetic polymorphisms versus concentration-dose ratio.

BACKGROUND AND JUSTIFICATION: The strategy of the concentration-dose (C/D) approach and the different profiles of tacrolimus (Tac) according to the cytochrome P450 polymorphisms (CYPs) focus on the metabolism of Tac and are proposed as tools for the follow-up of transplant patients. The objective of this study is to analyse both strategies to confirm whether the stratification of patients according to the pharmacokinetic behaviour of C/D corresponds to the classification according to their CYP3A4/5 cluster metabolizer profile. MATERIALS AND METHODS: 425 kidney transplant patients who received Tac as immunosuppressive treatment have been included. The concentration/dose ratio (C/D) was used to divide patients in terciles and classify them according to their Tac metabolism rate (fast, intermediate, and slow). Based on CYP3A4 and A5 polymorphisms, patients were classified into 3 metabolizer groups: fast (CYP3A5*1 carriers and CYP34A*1/*1), intermediate (CYP3A5*3/3 and CYP3A4*1/*1) and slow (CYP3A5*3/*3 and CYP3A4*22 carriers). RESULTS: When comparing patients included in each metabolizer group according to C/D ratio, 47% (65/139) of the fast metabolizers, 85% (125/146) of the intermediate and only 12% (17/140) of the slow also fitted in the homonym genotype group. Statistically lower Tac concentrations were observed in the fast metabolizers group and higher Tac concentrations in the slow metabolizers when compared with the intermediate group both in C/D ratio and polymorphisms criteria. High metabolizers required approximately 60% more Tac doses than intermediates throughout follow-up, while poor metabolizers required approximately 20% fewer doses than intermediates. Fast metabolizers classified by both criteria presented a higher percentage of times with sub-therapeutic blood Tac concentration values. CONCLUSION: Determination of the metabolizer phenotype according to CYP polymorphisms or the C/D ratio allows patients to be distinguished according to their exposure to Tac. Probably the combination of both classification criteria would be a good tool for managing Tac dosage for transplant patients.

A prospective controlled, randomized clinical trial of kidney transplant recipients developed personalized tacrolimus dosing using model-based Bayesian Prediction.

For three decades, tacrolimus (Tac) dose adjustment in clinical practice has been calculated empirically according to the manufacturer's labeling based on a patient's body weight. Here, we developed and validated a Population pharmacokinetic (PPK) model including pharmacogenetics (cluster CYP3A4/CYP3A5), age, and hematocrit. Our study aimed to assess the clinical applicability of this PPK model in the achievement of Tac Co (therapeutic trough Tac concentration) compared to the manufacturer's labelling dosage. A prospective two-arm, randomized, clinical trial was conducted to determine Tac starting and subsequent dose adjustments in 90 kidney transplant recipients. Patients were randomized to a control group with Tac adjustment according to the manufacturer's labeling or the PPK group adjusted to reach target Co (6-10 ng/ml) after the first steady state (primary endpoint) using a Bayesian prediction model (NONMEM). A significantly higher percentage of patients from the PPK group (54.8%) compared with the control group (20.8%) achieved the therapeutic target fulfilling 30% of the established superiority margin defined. Patients receiving PPK showed significantly less intra-patient variability compared to the control group, reached the Tac Co target sooner (5 days vs 10 days), and required significantly fewer Tac dose modifications compared to the control group within 90 days following kidney transplant. No statistically significant differences occurred in clinical outcomes. Thus, PPK-based Tac dosing offers significant superiority for starting Tac prescription over classical labeling-based dosing according to the body weight, which may optimize Tac-based therapy in the first days following transplantation.

The Effect of Intracellular Tacrolimus Exposure on Calcineurin Inhibition in Immediate- and Extended-Release Tacrolimus Formulations.

Despite intensive monitoring of whole blood tacrolimus concentrations, acute rejection after kidney transplantation occurs during tacrolimus therapy. Intracellular tacrolimus concentrations could better reflect exposure at the site of action and its pharmacodynamics (PD). Intracellular pharmacokinetic (PK) profile following different tacrolimus formulations (immediate-release (TAC-IR) and extended-release (TAC-LCP)) remains unclear. Therefore, the aim was to study intracellular tacrolimus PK of TAC-IR and TAC-LCP and its correlation with whole blood (WhB) PK and PD. A post-hoc analysis of a prospective, open-label, crossover investigator-driven clinical trial (NCT02961608) was performed. Intracellular and WhB tacrolimus 24 h time-concentration curves were measured in 23 stable kidney transplant recipients. PD analysis was evaluated measuring calcineurin activity (CNA) and simultaneous intracellular PK/PD modelling analysis was conducted. Higher dose-adjusted pre-dose intracellular concentrations (C0 and C24) and total exposure (AUC0-24) values were found for TAC-LCP than TAC-IR. Lower intracellular peak concentration (Cmax) was found after TAC-LCP. Correlations between C0, C24 and AUC0-24 were observed within both formulations. Intracellular kinetics seems to be limited by WhB disposition, in turn, limited by tacrolimus release/absorption processes from both formulations. The faster intracellular elimination after TAC-IR was translated into a more rapid recovery of CNA. An Emax model relating % inhibition and intracellular concentrations, including both formulations, showed an IC50, a concentration to achieve 50% CNA inhibition, of 43.9 pg/million cells.

Comparison of Three Renal Function Formulas for Ganciclovir/Valganciclovir Dose Individualization in CMV-Infected Solid Organ Transplantation Patients Using a Population Approach.

BACKGROUND AND OBJECTIVE: The gold standard treatment of established cytomegalovirus infection or prevention in solid organ transplantation is the intravenous administration of ganciclovir (GCV) or oral administration of valganciclovir (VGCV), both adjusted to the renal function. In both instances, there is a high interindividual pharmacokinetic variability, mainly owing to the wide range of variation of both the renal function and body weight. Therefore, accurate estimation of the renal function is crucial for GCV/VGCV dose optimization. This study aimed to compare three different formulas for estimating the renal function in solid organ transplantation patients with cytomegalovirus infection, for individualizing antiviral therapy with GCV/VGCV, using a population approach. METHODS: A population pharmacokinetic analysis was performed using NONMEM 7.4. A total of 650 plasma concentrations obtained after intravenous GCV and oral VGCV administrations were analyzed, from intensive and sparse sampling designs. Three different population pharmacokinetic models were built with the renal function given by Cockcroft-Gault, Modification of Diet in Renal Disease, or Chronic Kidney Disease EPIdemiology Collaboration (CKD-EPI) formulas. Pharmacokinetic parameters were allometrically scaled to body weight. RESULTS: The CKD-EPI formula was identified as the best predictor of between-patient variability in GCV clearance. Internal and external validation techniques showed that the CKD-EPI model had better stability and performed better compared with the others. CONCLUSIONS: The model based on the more accurate estimation of the renal function with the CKD-EPI formula and body weight as a size metric most used in the clinical practice can refine initial dose recommendations and contribute to GCV and VGCV dose individualization when required in the prevention or treatment of cytomegalovirus infection in solid organ transplantation patients.

Combining neutrophil and macrophage biomarkers to detect active disease in ANCA vasculitis: a combinatory model of calprotectin and urine CD163.

Background: CD163 and calprotectin have been proposed as biomarkers of active renal vasculitis. This study aimed to determine whether the combination of serum/urine calprotectin (s/uCalprotectin) and urinary soluble CD163 (suCD163) increases their individual performance as activity biomarkers. Methods: We included 138 patients diagnosed with ANCA vasculitis (n = 52 diagnostic phase, n = 86 remission). The study population was divided into the inception (n = 101) and the validation cohorts (n = 37). We determined the s/uCalprotectin and suCD163 concentration using enzyme-linked immunoassay at the diagnostic or at the remission phase. Receiver operating characteristic (ROC) curves were conducted to assess the biomarkers' classificatory values. We elaborated a combinatorial biomarker model in the inception cohort. The ideal cutoffs were used in the validation cohort to confirm the model's accuracy in the distinction between active disease and remission. We added the classical ANCA vasculitis activity biomarkers to the model to increase the classificatory performance. Results: The concentrations of sCalprotectin and suCD163 were higher in the diagnostic compared with the remission phase (P = .013 and P < .0001). According to the ROC curves, sCalprotectin and suCD163 were accurate biomarkers to discern activity [area under the curve 0.73 (0.59-0.86), P = .015 and 0.88 (0.79-0.97), P < .0001]. The combinatory model with the best performance in terms of sensitivity, specificity and likelihood ratio included sCalprotectin, suCD163 and haematuria. Regarding the inception and the validation cohort, we obtained a sensitivity, specificity and likelihood ratio of 97%, 90% and 9.7, and 78%, 94% and 13, respectively. Conclusions: In patients with ANCA vasculitis, a predictive model combining sCalprotectin, suCD163 and haematuria could be useful in detecting active kidney disease.

Renoprotective Effect of Agalsidase Alfa: A Long-Term Follow-Up of Patients with Fabry Disease.

Fabry disease is a rare lysosomal storage disorder caused by mutations in the GLA gene, which, without treatment, can cause significant renal dysfunction. We evaluated the effects of enzyme replacement therapy with agalsidase alfa on renal decline in patients with Fabry disease using data from the Fabry Outcome Survey (FOS) registry. Male patients with Fabry disease aged >16 years at agalsidase alfa start were stratified by low (≤0.5 g/24 h) or high (>0.5 g/24 h) baseline proteinuria and by 'classic' or 'non-classic' phenotype. Overall, 193 male patients with low (n = 135) or high (n = 58) baseline proteinuria were evaluated. Compared with patients with low baseline proteinuria, those with high baseline proteinuria had a lower mean ± standard deviation baseline eGFR (89.1 ± 26.2 vs. 106.6 ± 21.8 mL/min/1.73 m2) and faster mean ± standard error eGFR decline (−3.62 ± 0.42 vs. −1.61 ± 0.28 mL/min/1.73 m2 per year; p < 0.0001). Patients with classic Fabry disease had similar rates of eGFR decline irrespective of baseline proteinuria; only one patient with non-classic Fabry disease had high baseline proteinuria, preventing meaningful comparisons between groups. In this analysis, baseline proteinuria significantly impacted the rate of eGFR decline in the overall population, suggesting that early treatment with good proteinuria control may be associated with renoprotective effects.

Dual Costimulatory and Coinhibitory Targeting with a Hybrid Fusion Protein as an Immunomodulatory Therapy in Lupus Nephritis Mice Models.

Systemic lupus erythematosus is a complex autoimmune disorder mostly mediated by B-cells in which costimulatory signals are involved. This immune dysregulation can cause tissue damage and inflammation of the kidney, resulting in lupus nephritis and chronic renal failure. Given the previous experience reported with CTLA4-Ig as well as recent understanding of the PD-1 pathway in this setting, our group was encouraged to evaluate, in the NZBWF1 model, a human fusion recombinant protein (Hybri) with two domains: CTLA4, blocking the CD28-CD80 costimulatory pathway, and PD-L2, exacerbating the PD-1-PD-L2 coinhibitory pathway. After achieving good results in this model, we decided to validate the therapeutic effect of Hybri in the more severe MRL/lpr model of lupus nephritis. The intraperitoneal administration of Hybri prevented the progression of proteinuria and anti-dsDNA antibodies to levels like those of cyclophosphamide and reduced the histological score, infiltration of B-cells, T-cells, and macrophages and immune deposition in both lupus-prone models. Additionally, Hybri treatment produced changes in both inflammatory-related circulating cytokines and kidney gene expression. To summarize, both in vivo studies revealed that the Hybri effect on costimulatory-coinhibitory pathways may effectively mitigate lupus nephritis, with potential for use as a maintenance therapy.

The Hidden Side of Complement Regulator C4BP: Dissection and Evaluation of Its Immunomodulatory Activity.

C4b-binding protein (C4BP) is a well-known regulator of the complement system that holds additional and important activities unrelated to complement inhibition. Recently, we have described a novel immunomodulatory activity in the minor C4BP(ß-) isoform directly acting over inflammatory phagocytes. Here we show that incorporation of the ß-chain to the C4BP α-chain oligomer interferes with this immunomodulatory activity of C4BP. Moreover, an oligomeric form including only the complement control protein 6 (CCP6) domain of the C4BP α-chain (PRP6-HO7) is sufficient to "reprogram" monocyte-derived DCs (Mo-DCs) from a pro-inflammatory and immunogenic phenotype to an anti-inflammatory and tolerogenic state. PRP6-HO7 lacks complement regulatory activity but retains full immunomodulatory activity over inflammatory Mo-DCs induced by TLRs, characterized by downregulation of relevant surface markers such as CD83, HLA-DR, co-stimulatory molecules such as CD86, CD80 and CD40, and pro-inflammatory cytokines such as IL-12 and TNF-α. Furthermore, PRP6-HO7-treated Mo-DCs shows increased endocytosis, significantly reduced CCR7 expression and CCL21-mediated chemotaxis, and prevents T cell alloproliferation. Finally, PRP6-HO7 shows also full immunomodulatory activity over Mo-DCs isolated from lupus nephritis patients with active disease, even without further pro-inflammatory stimulation. Therefore PRP6-HO7, retaining the immunomodulatory activity of C4BP(ß-) and lacking its complement regulatory activity, might represent a promising and novel alternative to treat autoimmune diseases.

The Role of Inflammasomes in Glomerulonephritis.

The inflammasome is an immune multiprotein complex that activates pro-caspase 1 in response to inflammation-inducing stimuli and it leads to IL-1ß and IL-18 proinflammatory cytokine production. NLRP1 and NLRP3 inflammasomes are the best characterized and they have been related to several autoimmune diseases. It is well known that the kidney expresses inflammasome genes, which can influence the development of some glomerulonephritis, such as lupus nephritis, ANCA glomerulonephritis, IgA nephropathy and anti-GBM nephropathy. Polymorphisms of these genes have also been described to play a role in autoimmune and kidney diseases. In this review, we describe the main characteristics, activation mechanisms, regulation and functions of the different inflammasomes. Moreover, we discuss the latest findings about the role of the inflammasome in several glomerulonephritis from three different points of view: in vitro, animal and human studies.

COVID-19 in Patients with Glomerular Disease: Follow-Up Results from the IRoc-GN International Registry.

Background: The acute and long-term effects of severe acute respiratory syndrome coronavirus 2 infection in individuals with GN are still unclear. To address this relevant issue, we created the International Registry of COVID-19 infection in GN. Methods: We collected serial information on kidney-related and -unrelated outcomes from 125 GN patients (63 hospitalized and 62 outpatients) and 83 non-GN hospitalized patients with coronavirus disease 2019 (COVID-19) and a median follow-up period of 6.4 (interquartile range 2.3-9.6) months after diagnosis. We used logistic regression for the analyses of clinical outcomes and linear mixed models for the longitudinal analyses of eGFR. All multiple regression models were adjusted for age, sex, ethnicity, and renin-angiotensin-aldosterone system inhibitor use. Results: After adjustment for pre-COVID-19 eGFR and other confounders, mortality and AKI did not differ between GN patients and controls (adjusted odds ratio for AKI=1.28; 95% confidence interval [CI], 0.46 to 3.60; P=0.64). The main predictor of AKI was pre-COVID-19 eGFR (adjusted odds ratio per 1 SD unit decrease in eGFR=3.04; 95% CI, 1.76 to 5.28; P<0.001). GN patients developing AKI were less likely to recover pre-COVID-19 eGFR compared with controls (adjusted 6-month post-COVID-19 eGFR=0.41; 95% CI, 0.25 to 0.56; times pre-COVID-19 eGFR). Shorter duration of GN diagnosis, higher pre-COVID-19 proteinuria, and diagnosis of focal segmental glomerulosclerosis or minimal change disease were associated with a lower post-COVID-19 eGFR. Conclusions: Pre-COVID-19 eGFR is the main risk factor for AKI regardless of GN diagnosis. However, GN patients are at higher risk of impaired eGFR recovery after COVID-19-associated AKI. These patients (especially those with high baseline proteinuria or a diagnosis of focal segmental glomerulosclerosis or minimal change disease) should be closely monitored not only during the acute phases of COVID-19 but also after its resolution.

In vivo CD40 Silencing by siRNA Infusion in Rodents and Evaluation by Kidney Immunostaining.

The co-stimulatory molecule CD40 and its ligand CD40L play a key role in the regulation of immunological processes and are involved in the pathophysiology of autoimmune and inflammatory diseases. Inhibition of the CD40-CD40L axis is a promising therapy, and a number of strategies and techniques have been designed to hinder its functionality. Our group has broad experience in silencing CD40 using RNAi technology, and here we summarize protocols for the systemic administration of a specific anti-CD40 siRNA in different rodents models, in addition to the subsequent quantification of CD40 expression in murine kidneys by immunostaining. The use of RNAi technology with specific siRNAs to silence genes is becoming an essential method to investigate gene functions and is rapidly emerging as a therapeutic tool. Graphic abstract: CD40 siRNA mechanism.

Recent Progress on Biodegradable Tissue Engineering Scaffolds Prepared by Thermally-Induced Phase Separation (TIPS).

Porous biodegradable scaffolds provide a physical substrate for cells allowing them to attach, proliferate and guide the formation of new tissues. A variety of techniques have been developed to fabricate tissue engineering (TE) scaffolds, among them the most relevant is the thermally-induced phase separation (TIPS). This technique has been widely used in recent years to fabricate three-dimensional (3D) TE scaffolds. Low production cost, simple experimental procedure and easy processability together with the capability to produce highly porous scaffolds with controllable architecture justify the popularity of TIPS. This paper provides a general overview of the TIPS methodology applied for the preparation of 3D porous TE scaffolds. The recent advances in the fabrication of porous scaffolds through this technique, in terms of technology and material selection, have been reviewed. In addition, how properties can be effectively modified to serve as ideal substrates for specific target cells has been specifically addressed. Additionally, examples are offered with respect to changes of TIPS procedure parameters, the combination of TIPS with other techniques and innovations in polymer or filler selection.

Acute tubulointerstitial nephritis induced by checkpoint inhibitors versus classical acute tubulointerstitial nephritis: are they the same disease?

BACKGROUND: The incidence of acute tubulointerstitial nephritis (ATIN) related to drugs has dramatically increased over recent years. A new subtype of ATIN, apparently different from classical drug-related ATIN, has emerged that has been related to the administration of immune checkpoint inhibitors (ICIs). We investigated these differences between ICI-related ATIN (ICI ATIN) and non-ICI-related ATIN in terms of clinical features, response to treatment with steroids and the evolution of kidney function. METHODS: A total of 47 patients diagnosed with ATIN from two centres were recruited. Of these, 13 patients presented with ATIN during ICI treatment and 34 were diagnosed with ATIN attributed to other drugs. The main demographic, clinical and analytical variables such as gender, age and current medication were recorded. The type of malignancy, oncological treatment, ICI dose and presence of extrarenal immune-related adverse events were also reviewed. Renal biopsy diagnosis, time to drug withdrawal and ATIN-specific treatment, as well as laboratory data during follow-up, were also studied. RESULTS: Patients diagnosed with ICI ATIN presented with lower creatinine (ICI ATIN 3.8 ± 1.03 versus classical ATIN 5.98 ± 4.15 mg/dL, P = 0.007) at diagnosis and higher urinary leucocyte counts (ICI ATIN 263.2 ± 418.04 versus classical ATIN 133.55 ± 284.62, P = 0.048) compared with patients with non-ICI-related ATIN. Time from initiation of the culprit drug to ATIN diagnosis was longer in patients with ICI ATIN than in those with classical ATIN (197.07 ± 184.99 versus 114.4 ± 352.16 days, P = 0.006). In addition, during follow-up, the slope of decreasing creatinine over time was lower for ICI ATIN compared with non-ICI-related ATIN. CONCLUSIONS: In this study, we analysed differences between ICI ATIN and classical ATIN. We found that patients with ICI ATIN presented with a larger latency period after culprit drug initiation, milder acute kidney injury and slower creatinine amelioration compared with those with classical ATIN. These results may, in part, be ascribed to potential differences in the pathological mechanisms involved in ATIN development, suggesting that ICI and classical ATIN may be different diseases with similar renal histologies.

Predictors of outcome in a Spanish cohort of patients with Fabry disease on enzyme replacement therapy.

Fabry disease may be treated by enzyme replacement therapy (ERT), but the impact of chronic kidney disease (CKD) on the response to therapy remains unclear. The aim of the present study was to analyse the incidence and predictors of clinical events in patients on ERT. STUDY DESIGN: Multicentre retrospective observational analysis of patients diagnosed and treated with ERT for Fabry disease. The primary outcome was the first renal, neurological or cardiological events or death during a follow-up of 60 months (24-120). RESULTS: In 69 patients (42 males, 27 females, mean age 44.6±13.7 years), at the end of follow-up, eGFR and the left ventricular septum thickness remained stable and the urinary albumin: creatinine ratio tended to decrease, but this decrease only approached significance in patients on agalsidase-beta (242-128mg/g (p=0.05). At the end of follow-up, 21 (30%) patients had suffered an incident clinical event: 6 renal, 2 neurological and 13 cardiological (including 3 deaths). Events were more frequent in patients with baseline eGFR≤60ml/min/1.73m2 (log Rank 12.423, p=0.001), and this remained significant even after excluding incident renal events (log Rank 4.086, p=0.043) and in males and in females. Lower baseline eGFR was associated with a 3- to 7-fold increase the risk of clinical events in different Cox models. CONCLUSIONS: GFR at the initiation of ERT is the main predictor of clinical events, both in males and in females, suggesting that start of ERT prior to the development of CKD is associated with better outcomes.

Acute Tubulointerstitial Nephritis in Clinical Oncology: A Comprehensive Review.

Acute kidney injury in patients who suffer a malignancy is a common complication. Due to its high prevalence and effective treatment, one of the most frequent causes that both oncologists and nephrologists must be aware of is acute tubulointerstitial nephritis (ATIN). ATIN is an immunomediated condition and the hallmark of the disease, with the presence of a tubulointerstitial inflammatory infiltrate in the renal parenchyma. This infiltrate is composed mainly of T lymphocytes that can be accompanied by macrophages, neutrophils, or eosinophils among other cells. One of the major causes is drug-related ATIN, and some antineoplastic treatments have been related to this condition. Worthy of note are the novel immunotherapy treatments aimed at enhancing natural immunity in order to defeat cancer cells. In the context of the immunosuppression status affecting ATIN patients, some pathogen antigens can trigger the development of the disease. Finally, hematological malignancies can also manifest in the kidney leading to ATIN, even at the debut of the disease. In this review, we aim to comprehensively examine differential diagnosis of ATIN in the setting of a neoplastic patient.

Dual and Opposite Costimulatory Targeting with a Novel Human Fusion Recombinant Protein Effectively Prevents Renal Warm Ischemia Reperfusion Injury and Allograft Rejection in Murine Models.

Many studies have shown both the CD28-D80/86 costimulatory pathway and the PD-1-PD-L1/L2 coinhibitory pathway to be important signals in modulating or decreasing the inflammatory profile in ischemia-reperfusion injury (IRI) or in a solid organ transplant setting. The importance of these two opposing pathways and their potential synergistic effect led our group to design a human fusion recombinant protein with CTLA4 and PD-L2 domains named HYBRI. The objective of our study was to determine the HYBRI binding to the postulated ligands of CTLA4 (CD80) and PD-L2 (PD-1) using the Surface Plasmon Resonance technique and to evaluate the in vivo HYBRI effects on two representative kidney inflammatory models-rat renal IRI and allogeneic kidney transplant. The Surface Plasmon Resonance assay demonstrated the avidity and binding of HYBRI to its targets. HYBRI treatment in the models exerted a high functional and morphological improvement. HYBRI produced a significant amelioration of renal function on day one and two after bilateral warm ischemia and on days seven and nine after transplant, clearly prolonging the animal survival in a life-sustaining renal allograft model. In both models, a significant reduction in histological damage and CD3 and CD68 infiltrating cells was observed. HYBRI decreased the circulating inflammatory cytokines and enriched the FoxP3 peripheral circulating, apart from reducing renal inflammation. In conclusion, the dual and opposite costimulatory targeting with that novel protein offers a good microenvironment profile to protect the ischemic process in the kidney and to prevent the kidney rejection, increasing the animal's chances of survival. HYBRI largely prevents the progression of inflammation in these rat models.

Sustained Inhibition of Calcineurin Activity With a Melt-Dose Once-daily Tacrolimus Formulation in Renal Transplant Recipients.

Tacrolimus (Tac) is the cornerstone calcineurin inhibitor in transplantation. Extended-release Meltdose formulation (Tac-LCP) offers better bioavailability compared with immediate-release formulation (Tac-IR). We postulated that the less fluctuating pharmacokinetic (PK) profile of Tac-LCP might maintain a sustained inhibition of calcineurin activity (CNA) between dose intervals. Higher concentrations (peak plasma concentration (Cmax )) after Tac-IR may not result in a more potent CNA inhibition due to a capacity-limited effect. This study was aimed at evaluating the pharmacodynamic (PD)/PK profiles of Tac-IR compared with Tac-LCP. An open-label, prospective, nonrandomized, investigator-driven study was conducted. Twenty-five kidney transplant recipients receiving Tac-IR were switched to Tac-LCP. Before and 28 days after conversion, intensive CNA-PD and PK sampling were conducted using ultra-high-performance liquid chromatography-tandem accurate mass spectrometry. PD nonlinear mixed effects model was performed in Phoenix-WinNonlin. Statistically significant higher Cmax (P < 0.001) after Tac-IR did not result in lower CNA as compared with after Tac-LCP (P = 0.860). Tac-LCP showed a statistically more maintained CNA inhibition between dose intervals (area under the effect-time curve from 0 to 24 hours (AUE0-24h )) compared with Tac-IR, in which CNA returned to predose levels after 4 hours of drug intake (373.8 vs. 290.5 pmol RII·h/min·mg prot, Tac-LCP vs. Tac-IR; P = 0.039). No correlation was achieved between any PD and PK parameters in any formulations. Moreover, Tac concentration to elicit a 50% of the maximum response (half-maximal inhibitory concentration) was 9.24 ng/mL. The higher Cmax after Tac-IR does not result in an additional CNA inhibition compared with Tac-LCP attributable to a capacity-limited effect. Tac-LCP may represent an improvement of the PD of Tac due to the more sustained CNA inhibition during dose intervals.

Extracapillary proliferation scoring correlates with renal outcome and contributes to stratification in adult patients with immunoglobulin A nephropathy.

BACKGROUND: The revised Oxford classification of diagnostic renal biopsies has been proposed to aid in the prediction of renal outcome. We aimed to validate the histological crescents and interstitial fibrosis and tubular atrophy (IFTA) subgrouping, and to investigate the additional value of the proportion of crescents (CatPE) in the prediction of renal outcome. METHODS: Data were retrospectively collected over 10 years, from the time of diagnosis, by systematic review of medical records from 90 patients with renal biopsies recruited to cohorts from two hospitals in Spain. Patients were classified into three groups for the analysis: CatPE >25% (C2), CatPE <25% (C1) and without this type of lesion (C0). The end point was renal survival defined by either >50% reduction in glomerular filtrate rate or end-stage renal disease. RESULTS: Renal survival at 5 years was 90% in group C0, 81% in group C1 and 31% in group C2 (P = 0.013). The presence of >25% crescents in the sample was associated with more severe disease when compared with <25%, as demonstrated by more interstitial fibrotic change and by lower estimated glomerular filtration rate at diagnosis, as well as worse renal function at 2 and 5 years. At the time of diagnosis and at 24 months, the group with IFTA >50% had poorer renal function compared with the other groups. CONCLUSIONS: We have confirmed the predictive value for renal survival of the revised Oxford classification in a two-centre study. We found worse renal outcome in patients with severe tubulointerstitial fibrosis and atrophy. Patients with extracapillary lesions >25% and IFTA >50% had a worse renal prognosis due to more severe kidney injury. These results contribute to patient stratification in immunoglobulin A nephropathy for therapeutic, epidemiological and basic research.