Bidirectional regulation of synaptic SUMOylation by Group 1 metabotropic glutamate receptors.

SUMOylation is a post-translational modification essential to cell homeostasis. A tightly controlled equilibrium between SUMOylation and deSUMOylation processes is also critical to the neuronal function including neurotransmitter release and synaptic transmission and plasticity. Disruption of the SUMOylation homeostasis in neurons is associated with several neurological disorders. The balance between the SUMOylation and deSUMOylation of substrate proteins is maintained by a group of deSUMOylation enzymes called SENPs. We previously showed that the activation of type 5 metabotropic glutamate receptors (mGlu5R) first triggers a rapid increase in synaptic SUMOylation and then upon the sustained activation of these receptors, the deSUMOylase activity of SENP1 allows the increased synaptic SUMOylation to get back to basal levels. Here, we combined the use of pharmacological tools with subcellular fractionation and live-cell imaging of individual hippocampal dendritic spines to demonstrate that the synaptic accumulation of the deSUMOylation enzyme SENP1 is bidirectionally controlled by the activation of type 1 mGlu1 and mGlu5 receptors. Indeed, the pharmacological blockade of mGlu1R activation during type 1 mGluR stimulation leads to a faster and greater accumulation of SENP1 at synapses indicating that mGlu1R acts as a brake to the mGlu5R-dependent deSUMOylation process at the post-synapse. Altogether, our findings reveal that type 1 mGluRs work in opposition to dynamically tune the homeostasis of SUMOylation at the mammalian synapse.

Impaired Integrated Stress Response and Mitochondrial Integrity Modulate Genotoxic Stress Impact and Lower the Threshold for Immune Signalling.

Mitochondria-nucleus communication during stress dictates cellular fate with consequences on the etiopathology of multiple age-related diseases. Impaired mitochondrial quality control through loss of function of the mitochondrial protease HtrA2 associates with accumulation of damaged mitochondria and triggers the integrated stress response, implicating the transcription factor CHOP. Here we have employed a combined model of impaired mitochondria quality control, namely HtrA2 loss of function, and/or integrated stress response, namely CHOP loss of function, and genotoxicity to address the distinctive roles of these cellular components in modulating intracellular and intercellular responses. The genotoxic agents employed were cancer therapeutic agents such as irradiation with X-ray and protons or treatment with the radiomimetic bleomycin. The irradiation had an enhanced effect in inducing DNA damage in cells with CHOP loss of function, while the bleomycin treatment induced more DNA damage in all the transgenic cells as compared to the control. The genetic modifications impaired the transmission of DNA damage signalling intercellularly. Furthermore, we have dissected the signalling pathways modulated by irradiation in selected genotypes with RNA sequencing analysis. We identified that loss of HtrA2 and CHOP function, respectively, lowers the threshold where irradiation may induce the activation of innate immune responses via cGAS-STING; this may have a significant impact on decisions for combined therapeutic approaches for various diseases.

Acid Sphingomyelinase Deficiency Type B Patient-Derived Liver Organoids Reveals Altered Lysosomal Gene Expression and Lipid Homeostasis.

Acid sphingomyelinase deficiency (ASMD) or Niemann-Pick disease type A (NPA), type B (NPB) and type A/B (NPA/B), is a rare lysosomal storage disease characterized by progressive accumulation of sphingomyelin (SM) in the liver, lungs, bone marrow and, in severe cases, neurons. A disease model was established by generating liver organoids from a NPB patient carrying the p.Arg610del variant in the SMPD1 gene. Liver organoids were characterized by transcriptomic and lipidomic analysis. We observed altered lipid homeostasis in the patient-derived organoids showing the predictable increase in sphingomyelin (SM), together with cholesterol esters (CE) and triacylglycerides (TAG), and a reduction in phosphatidylcholine (PC) and cardiolipins (CL). Analysis of lysosomal gene expression pointed to 24 downregulated genes, including SMPD1, and 26 upregulated genes that reflect the lysosomal stress typical of the disease. Altered genes revealed reduced expression of enzymes that could be involved in the accumulation in the hepatocytes of sphyngoglycolipids and glycoproteins, as well as upregulated genes coding for different glycosidases and cathepsins. Lipidic and transcriptome changes support the use of hepatic organoids as ideal models for ASMD investigation.

Study Models of Drug-Drug Interactions Involving P-Glycoprotein: The Potential Benefit of P-Glycoprotein Modulation at the Kidney and Intestinal Levels.

P-glycoprotein (P-gp) is a crucial membrane transporter situated on the cell's apical surface, being responsible for eliminating xenobiotics and endobiotics. P-gp modulators are compounds that can directly or indirectly affect this protein, leading to changes in its expression and function. These modulators can act as inhibitors, inducers, or activators, potentially causing drug-drug interactions (DDIs). This comprehensive review explores diverse models and techniques used to assess drug-induced P-gp modulation. We cover several approaches, including in silico, in vitro, ex vivo, and in vivo methods, with their respective strengths and limitations. Additionally, we explore the therapeutic implications of DDIs involving P-gp, with a special focus on the renal and intestinal elimination of P-gp substrates. This involves enhancing the removal of toxic substances from proximal tubular epithelial cells into the urine or increasing the transport of compounds from enterocytes into the intestinal lumen, thereby facilitating their excretion in the feces. A better understanding of these interactions, and of the distinct techniques applied for their study, will be of utmost importance for optimizing drug therapy, consequently minimizing drug-induced adverse and toxic effects.

Protective Effect of Quercetin 3-O-Glucuronide against Cisplatin Cytotoxicity in Renal Tubular Cells.

Quercetin, a flavonoid with promising therapeutic potential, has been shown to protect from cisplatin nephrotoxicity in rats following intraperitoneal injection, but its low bioavailability curtails its prospective clinical utility in oral therapy. We recently developed a micellar formulation (P-quercetin) with enhanced solubility and bioavailability, and identical nephroprotective properties. As a first aim, we herein evaluated the oral treatment with P-quercetin in rats, which displayed no nephroprotection. In order to unravel this discrepancy, quercetin and its main metabolites were measured by HPLC in the blood and urine after intraperitoneal and oral administrations. Whilst quercetin was absorbed similarly, the profile of its metabolites was different, which led us to hypothesize that nephroprotection might be exerted in vivo by a metabolic derivate. Consequently, we then aimed to evaluate the cytoprotective capacity of quercetin and its main metabolites (quercetin 3-O-glucoside, rutin, tamarixetin, isorhamnetin and quercetin 3-O-glucuronide) against cisplatin toxicity, in HK-2 and NRK-52E tubular cell lines. Cells were incubated for 6 h with quercetin, its metabolites or vehicle (pretreatment), and subsequently 18 h in cotreatment with 10-300 µM cisplatin. Immediately after treatment, cell cultures were subject to the MTT technique as an index of cytotoxicity and photographed under light microscopy for phenotypic assessment. Quercetin afforded no direct cytoprotection and quercetin-3-O-glucuronide was the only metabolite partially preventing the effect of cisplatin in cultured tubule cells. Our results identify a metabolic derivative of quercetin contributing to its nephroprotection and prompt to further explore exogenous quercetin-3-O-glucuronide in the prophylaxis of tubular nephrotoxicity.

Microglial CX3CR1 production increases in Alzheimer's disease and is regulated by noradrenaline.

The loss of noradrenergic neurons and subsequent reduction of brain noradrenaline (NA) levels are associated with the progression of Alzheimer's disease (AD). This seems to be due mainly to the ability of NA to reduce the activation of microglial cells. We previously observed that NA induces the production of the chemokine Fractalkine/CX3CL1 in neurons. The activation of microglial CX3CR1, sole receptor for CX3CL1, reduces the activation of microglia, which is known to largely contribute to the neuronal damage characteristic of AD. Therefore, alterations of CX3CR1 production in microglia could translate into the enhancement or inhibition of CX3CL1 anti-inflammatory effects. In order to determine if microglial CX3CR1 production is altered in AD and if NA can control it, CX3CR1 expression and synthesis were analyzed in 5xFAD mice and human AD brain samples. In addition, the effects of NA and its reuptake inhibitor reboxetine were analyzed in microglial cultures and mice respectively. Our results indicate that in AD CX3CR1 production is increased in the brain cortex and that reboxetine administration further increases it and enhances microglial reactivity toward amyloid beta plaques. However, direct administration of NA to primary rat microglia or human HMC3 cells inhibits CX3CR1 production, suggesting that microglia responses to NA may be altered in the absence of CX3CL1-producing neurons or other nonmicroglial external factors.

Activated gut-homing CD8+ T cells for coeliac disease diagnosis on a gluten-free diet.

BACKGROUND: The diagnosis of coeliac disease (CD) in individuals that have started a gluten-free diet (GFD) without an adequate previous diagnostic work-out is a challenge. Several immunological assays such as IFN-γ ELISPOT have been developed to avoid the need of prolonged gluten challenge to induce the intestinal damage. We aimed to evaluate the diagnostic accuracy of activated gut-homing CD8+ and TCRγδ+ T cells in blood after a 3-day gluten challenge and to compare it with the performance of IFN-γ ELISPOT in a HLA-DQ2.5 subsample. METHODS: A total of 22 CD patients and 48 non-CD subjects, all of them following a GFD, underwent a 3-day 10-g gluten challenge. The percentage of two T cell subsets (CD8+ CD103+ ß7hi CD38+/total CD8+ and TCRγδ+ CD103+ ß7hi CD38+/total TCRγδ+) in fresh peripheral blood drawn baseline and 6 days after the challenge was determined by flow cytometry. IFN-γ ELISPOT assays were also performed in HLA-DQ2.5 participants. ROC curve analysis was used to assess the diagnostic performance of the CD8+ T cell response and IFN-γ ELISPOT. RESULTS: Significant differences between the percentage of the two studied subsets of CD8+ and TCRγδ+ cells at days 0 and 6 were found only when considering CD patients (p < 10-3 vs. non-CD subjects). Measuring activated CD8+ T cells provided accurate CD diagnosis with 95% specificity and 97% sensitivity, offering similar results than IFN-γ ELISPOT. CONCLUSIONS: The results provide a highly accurate blood test for CD diagnosis in patients on a GFD of easy implementation in daily clinical practice.

Post-translational modifications of the Fragile X Mental Retardation Protein in neuronal function and dysfunction.

The Fragile X Mental Retardation Protein (FMRP) is an RNA-binding protein essential to the regulation of local translation at synapses. In the mammalian brain, synapses are constantly formed and eliminated throughout development to achieve functional neuronal networks. At the molecular level, thousands of proteins cooperate to accomplish efficient neuronal communication. Therefore, synaptic protein levels and their functional interactions need to be tightly regulated. FMRP generally acts as a translational repressor of its mRNA targets. FMRP is the target of several post-translational modifications (PTMs) that dynamically regulate its function. Here we provide an overview of the PTMs controlling the FMRP function and discuss how their spatiotemporal interplay contributes to the physiological regulation of FMRP. Importantly, FMRP loss-of-function leads to Fragile X syndrome (FXS), a rare genetic developmental condition causing a range of neurological alterations including intellectual disability (ID), learning and memory impairments, autistic-like features and seizures. Here, we also explore the possibility that recently reported missense mutations in the FMR1 gene disrupt the PTM homoeostasis of FMRP, thus participating in the aetiology of FXS. This suggests that the pharmacological targeting of PTMs may be a promising strategy to develop innovative therapies for patients carrying such missense mutations.

A Micellar Formulation of Quercetin Prevents Cisplatin Nephrotoxicity.

The antioxidant flavonoid quercetin has been shown to prevent nephrotoxicity in animal models and in a clinical study and is thus a very promising prophylactic candidate under development. Quercetin solubility is very low, which handicaps clinical application. The aim of this work was to study, in rats, the bioavailability and nephroprotective efficacy of a micellar formulation of Pluronic F127-encapsulated quercetin (P-quercetin), with improved hydrosolubility. Intraperitoneal administration of P-quercetin leads to an increased plasma concentration and bioavailability of quercetin compared to the equimolar administration of natural quercetin. Moreover, P-quercetin retains overall nephroprotective properties, and even slightly improves some renal function parameters, when compared to natural quercetin. Specifically, P-quercetin reduced the increment in plasma creatinine (from 3.4 ± 0.5 to 1.2 ± 0.3 mg/dL) and urea (from 490.9 ± 43.8 to 184.1 ± 50.1 mg/dL) and the decrease in creatinine clearance (from 0.08 ± 0.02 to 0.58 ± 0.19 mL/min) induced by the nephrotoxic chemotherapeutic drug cisplatin, and it ameliorated histological evidence of tubular damage. This new formulation with enhanced kinetic and biopharmaceutical properties will allow for further exploration of quercetin as a candidate nephroprotector at lower dosages and by administration routes oriented towards its clinical use.

[Towards healthy pathways: Effect of nutrition labels on eating behaviours in a university canteen]. / Hacia rutas saludables: efecto de las etiquetas nutricionales en las conductas alimentarias en un comedor universitario.

OBJECTIVE: To evaluate the effectiveness of including nutritional and food properties information in a university canteen in Salamanca (Spain) to promote healthy eating behaviours. DESIGN: Experimental and correlational cross-sectional study. LOCATION: University Dining Hall of Salamanca (Spain). PARTICIPANTS: In the experiment, information was collected on the choice of 1122 menus by university students. The questionnaire was answered by 48 university students who participated in the experiment. MAIN MEASUREMENTS: Mixed methodology (field experiment and online questionnaire). The independent variable was the inclusion or not of nutritional information from the menus. The questionnaire was used to evaluate the students' attitude towards this type of tool. RESULTS: The experiment shows an improvement in the diet of university students with the inclusion of information elements that appeal to the healthiest choice, increasing their consumption of fruit, vegetables, legumes, fish and white meat. The students surveyed showed a high degree of receptivity to these health promotion tools. Despite this, their self-perception of dietary improvement was more optimistic than that quantified in the experiment. University students showed a very high degree of approval of other health promotion tools, especially those of an educational and informative nature. A greater concern for diet was associated with greater support for these tools. CONCLUSION: There is an improvement in the diet of university students and a positive attitude towards health promotion tools, especially by those with a healthier self-perception. There is a need for new tools based on behavioural sciences in health promotion by private industry and public entities.

Systematic review and meta-analysis of the efficacy of clinically tested protectants of cisplatin nephrotoxicity.

INTRODUCTION: Cisplatin is a potent antineoplastic drug that has been widely used to treat a number of solid tumors. However, a high incidence of renal damage observed in patients has led researchers to search for alternate strategies that prevent or at least reduce the cisplatin-induced nephrotoxicity. The objective of the present study was to conduct a systematic review and a subsequent meta-analysis to evaluate and identify compounds with effective antitumor activity and lesser side effects that could provide protection against cisplatin-induced nephrotoxicity. METHODS: The study included all placebo-controlled trials published up to December 2017 that met the inclusion criteria. A total of 22 articles were finally included to extract the following information: number of patients, doses of cisplatin and protectant, qualitative (acute kidney injury incidence) and quantitative (plasma creatinine, blood urea nitrogen, and creatinine clearance) indicators of renal function. The odds ratio or the mean difference (95% confidence interval) of each parameter was calculated for each study and group of studies. RESULTS: The results of this meta-analysis show that there is great variability in the nephroprotective capacity of a variety of products evaluated. Of all the compounds tested, only magnesium sulfate and cystone were found to exert protective effects. However, more studies need to be conducted to confirm these results. CONCLUSIONS: The administration of 1 g of Mg i.v. seems to be the best strategy for the prevention of cisplatin nephrotoxicity.

The synaptic balance between sumoylation and desumoylation is maintained by the activation of metabotropic mGlu5 receptors.

Sumoylation is a reversible post-translational modification essential to the modulation of neuronal function, including neurotransmitter release and synaptic plasticity. A tightly regulated equilibrium between the sumoylation and desumoylation processes is critical to the brain function and its disruption has been associated with several neurological disorders. This sumoylation/desumoylation balance is governed by the activity of the sole SUMO-conjugating enzyme Ubc9 and a group of desumoylases called SENPs, respectively. We previously demonstrated that the activation of type 5 metabotropic glutamate receptors (mGlu5R) triggers the transient trapping of Ubc9 in dendritic spines, leading to a rapid increase in the overall synaptic sumoylation. However, the mechanisms balancing this increased synaptic sumoylation are still not known. Here, we examined the diffusion properties of the SENP1 enzyme using a combination of advanced biochemical approaches and restricted photobleaching/photoconversion of individual hippocampal spines. We demonstrated that the activation of mGlu5R leads to a time-dependent decrease in the exit rate of SENP1 from dendritic spines. The resulting post-synaptic accumulation of SENP1 restores synaptic sumoylation to initial levels. Altogether, our findings reveal the mGlu5R system as a central activity-dependent mechanism to maintaining the homeostasis of sumoylation at the mammalian synapse.

Influence of HLA on clinical and analytical features of pediatric celiac disease.

BACKGROUND: Celiac disease (CD) is triggered by gluten and related prolamines in genetically susceptible individuals. We aimed to investigate the influence of HLA-DQ genotypes in clinical, serological and histological features related to CD. METHODS: A retrospective observational study was performed including 463 Spanish patients with biopsy-proven CD. Clinical, serological, histological and HLA-DQ genetic data were collected from each participant. The presence of a family history of CD was also considered. Bivariate (chi-square tests or the Fisher's exact test) and multivariate (logistic regression after adjusting for age and sex) analyses were performed to assess the association between clinical and laboratory parameters with HLA-DQ. RESULTS: A predominance of females (62%), classical clinical presentation (86%) and positive anti-transglutaminase 2/endomysium antibodies (99%) was observed in our sample, with a mean age at onset of 2.6 ± 0.1 years. Five percent of our patients were first-degree relatives of subjects with CD, with HLA-DQ genetics showing increased homozygosity of HLA-DQ2.5 (p = 0.03) and HLA-DQ8 (p = 0.09). In the non-CD family history group, an association between delayed disease onset and HLA-DQ8 carriage was observed (p < 0.001), besides an influence of HLA-DQB1*02 gene dosage on clinical presentation and severity of histological damage (after adjusting for age and sex, p = 0.05 and p = 0.02, respectively) and a trend towards presence of specific antibodies (p = 0.09). These associations could not be evaluated properly in the group of patients with affected first-degree relatives due to the small sample size. CONCLUSIONS: HLA-DQ genotypic frequencies differ slightly between CD patients depending on their family history of CD. In patients lacking CD first-degree relatives, carriage of HLA-DQ2.5 with double dose of HLA-DQB1*02 seems to be associated with classical clinical presentation and more severe histological damage.

Quercetin, a Promising Clinical Candidate for The Prevention of Contrast-Induced Nephropathy.

Iodinated contrast media (CM) are the leading cause of acute renal failure of toxic origin. Between 21% and 50% of patients that receive them develop contrast-induced nephropathy (CIN). All prophylactic measures used so far have failed to provide effective prevention. Since oxidative stress is involved in the damage, a possible preventive strategy could be the administration of antioxidant substances, such as quercetin. This compound has shown renoprotective effects in experimental studies. The aim of this study was to evaluate whether quercetin may be helpful in preventing CIN in patients undergoing coronary catheterization. A clinical phase II study was conducted. Patients were distributed in two groups, namely, CM (patients who only received contrast media) and CM+Q (patients who were pretreated with quercetin orally for 3-5 days). Results showed less incidence of CIN in the CM+Q group, possibly due to glomerular protection, evidenced by a lower increase in serum creatinine and albuminuria; and a lower decrease in the glomerular filtration rate (GFR). Furthermore, in this group, the relative risk of developing CIN observed in patients that received a high dose of contrast media was inferior. In conclusion, this is the first study that demonstrates that quercetin is a promising safe candidate in preventing CIN.

Transcriptome analysis of alcohol-treated microglia reveals downregulation of beta amyloid phagocytosis.

BACKGROUND: Microglial activation contributes to the neuropathology associated with chronic alcohol exposure and withdrawal, including the expression of inflammatory and anti-inflammatory genes. In the current study, we examined the transcriptome of primary rat microglial cells following incubation with alcohol alone, or alcohol together with a robust inflammatory stimulus. METHODS: Primary microglia were prepared from mixed rat glial cultures. Cells were incubated with 75 mM ethanol alone or with proinflammatory cytokines ("TII": IL1ß, IFNγ, and TNFα). Isolated mRNA was used for RNAseq analysis and qPCR. Effects of alcohol on phagocytosis were determined by uptake of oligomeric amyloid beta. RESULTS: Alcohol induced nitrite production in control cells and increased nitrite production in cells co-treated with TII. RNAseq analysis of microglia exposed for 24 h to alcohol identified 312 differentially expressed mRNAs ("Alc-DEs"), with changes confirmed by qPCR analysis. Gene ontology analysis identified phagosome as one of the highest-ranking KEGG pathways including transcripts regulating phagocytosis. Alcohol also increased several complement-related mRNAs that have roles in phagocytosis, including C1qa, b, and c; C3; and C3aR1. RNAseq analysis identified over 3000 differentially expressed mRNAs in microglia following overnight incubation with TII; and comparison to the group of Alc-DEs revealed 87 mRNAs modulated by alcohol but not by TII, including C1qa, b, and c. Consistent with observed changes in phagocytosis-related mRNAs, the uptake of amyloid beta1-42, by primary microglia, was reduced by alcohol. CONCLUSIONS: Our results define alterations that occur to microglial gene expression following alcohol exposure and suggest that alcohol effects on phagocytosis could contribute to the development of Alzheimer's disease.

N-acetylcysteine transforms necrosis into apoptosis and affords tailored protection from cisplatin cytotoxicity.

Nephrotoxicity is the main limitation to the dosage and anticancer efficacy of cisplatin. Cisplatin produces tubular epithelial cell apoptosis and necrosis depending on the concentration of the drug. Protection from cisplatin nephrotoxicity must therefore tackle both cell death modes. For its ability to reduce cisplatin reactivity, in addition to its antioxidant effect, we tested and found that N-acetylcysteine (NAC) was most effective at inhibiting cisplatin cytotoxicity. NAC has no significant effect on cell death induced by either cycloheximide or Fas activation, indicating a rather selective action. Pt-DNA-binding experiments suggest that the differential effectiveness of NAC is due to its capacity to quench cisplatin reactivity inside the cell. NAC abolishes cisplatin-induced apoptosis, and transforms the necrosis induced by high concentrations of cisplatin into apoptosis. In fact, NAC allows the anti-apoptotic molecule Bcl-2 to reduce the cell death caused by pro-necrotic concentrations of cisplatin, to a significantly greater extent than in the absence of NAC. In rats, a dosage of NAC that significantly ameliorates cisplatin nephrotoxicity, has little effect on gentamicin nephrotoxicity. These characteristics provide NAC with a rationale as a potential nephroprotectant specifically tailored to and especially effective for therapeutic courses with platinated antineoplastics, which prompts to deepening into further preclinical knowledge, and to initiate clinical studies with NAC and mixed therapies composed of NAC and antiapoptotic drugs.

The burden of constipation in psychiatric hospitals.

OBJECTIVE: In this study, we aimed to explore the total burden of constipation in our setting by measuring aggregate laxative consumption data and hospital admissions potentially associated with complications of chronic constipation. In addition, we aimed to determine point prevalence of individual laxative use. METHODS: This study was carried out across all public psychiatric hospitals in the Basque Country. First, laxative consumption data was obtained for the period from January 2008 to October 2016. Total laxative use was then calculated as the total number of individual daily defined doses (DDD). Second, we analyzed the number of admissions to any public acute health-care hospitals for constipation complications. Third, a cross prevalence study was performed to estimate the point constipation prevalence on December 2016. RESULTS: A mean consumption of oral laxatives around 1 DDD per stay and 1 enema per 100 stays was found. A total of 192 admissions potentially associated with constipation complications were recorded. At the time of the study, approximately half of admitted patients had at least one laxative prescribed. CONCLUSIONS: Our study highlights the important burden constipation represents in psychiatric inpatients. Although frequently neglected, it can lead to serious adverse clinical consequences.

In-gel protein digestion using acidic methanol produces a highly selective methylation of glutamic acid residues.

Mass-tolerant open search methods allow the high-throughput analysis of modified peptides by mass spectrometry. These techniques have paved the way to unbiased analysis of post-translational modifications in biological contexts, as well as of chemical modifications produced during the manipulation of protein samples. In this work, we have analyzed in-depth a wide variety of samples of different biological origin, including cells, extracellular vesicles, secretomes, centrosomes and tissue preparations, using Comet-ReCom, a recently improved version of the open search engine Comet-PTM. Our results demonstrate that glutamic acid residues undergo intensive methyl esterification when protein digestion is performed using in-gel techniques, but not using gel-free approaches. This effect was highly specific to Glu and was not found for other methylable residues such as Asp.

Evaluation of NAG, NGAL, and KIM-1 as Prognostic Markers of the Initial Evolution of Kidney Transplantation.

Kidney transplantation is the best option for end-stage chronic kidney disease. Transplant viability is conditioned by drugs' nephrotoxicity, ischemia-reperfusion damage, or acute rejection. An approach to improve graft survival is the identification of post-transplant renal function prognostic biomarkers. Our objective was to study three early kidney damage biomarkers (N-acetyl-d-glucosaminidase, NAG; neutrophil gelatinase-associated lipocalin, NGAL; and kidney injury molecule-1, KIM-1) in the initial period after transplantation and to identify possible correlations with main complications. We analysed those biomarkers in urine samples from 70 kidney transplant patients. Samples were taken on days 1, 3, 5, and 7 after intervention, as well as on the day that renal function stabilised (based on serum creatinine). During the first week after transplant, renal function improved based on serum creatinine evolution. However, increasing levels of biomarkers at different times during that first week could indicate tubular damage or other renal pathology. A relationship was found between NGAL values in the first week after transplantation and delayed graft function. In addition, higher NAG and NGAL, and lower KIM-1 values predicted a longer renal function stabilisation time. Therefore, urinary NAG, NGAL, and KIM-1 could constitute a predictive tool for kidney transplant complications, contributing to improve graft survival rates.

New Challenges in the Diagnosis of Kidney Damage Due to Immune Checkpoint Inhibitors Therapy: An Observational Clinical Study.

In recent years, immunotherapy has been postulated as one of the most effective strategies in the fight against cancer. The greatest success in this field has been achieved with the inhibition of molecules involved in slowing down the adaptive immune response by immune checkpoint inhibitors (ICIs). Despite its efficacy, ICI treatment has side effects. Regarding kidney damage, it is estimated that 4.9% of patients treated with ICIs develop renal injury. Furthermore, cancer patients who develop renal dysfunction have a worse prognosis. Current diagnostics are insufficient to predict the underlying renal injury and to identify the type of damage. Our hypothesis is that the renal injury could be subclinical, so the possibility of using new urinary biomarkers could be a useful diagnostic tool that would allow these patients to be managed in a preventive (risk biomarkers) and early (early biomarkers) way and even to clarify whether the renal damage is due to this therapy or to other factors (differential diagnostic biomarkers). A prospective study to validate risk and early and differential biomarkers in patients treated with ICIs is proposed to test this hypothesis. The results derived from this study will improve the clinical practice of cancer treatment with ICIs and therefore the life expectancy and quality of life of patients. Trial Registration: ClinicalTrials.gov, NCT04902846.