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Mesenchymal stromal cells (MSCs) exhibit anti-inflammatory and immune-regulatory properties, and preclinical studies suggest a potential benefit in solid organ transplantation. We report on the 1-year follow-up of an open-label phase I-II trial of a single infusion of third-party MSC post-kidney transplantation, in addition to standard immunosuppression. Ten kidney transplant recipients from deceased donors received third-party bone marrow MSCs (∼2 × 106/kg) on day 3 ± 2 post-transplant and were compared to 10 concurrent controls. No adverse effects were noted at MSC injection. One participant with a history of cardiac disease had a non-ST-elevation myocardial infarction approximately 3 hours after MSC infusion. Incidences of opportunistic infections and acute rejection were similar. At day 7 post-transplant, estimated glomerular filtration rate (eGFR) in MSC-treated recipients reached 48.6 ml/min/1.73m2, compared to 32.5 ml/min/1.73m2 in controls and 29.3 ml/min/1.73m2 in our overall cohort of kidney transplant recipients. No difference in eGFR was found at 1 year. MSC-treated recipients showed increased frequencies of regulatory T cells at day 30, with no significant change in B cell frequencies compared to concurrent controls. Four MSC-treated participants developed antibodies against MSC or shared kidney-MSC HLA, with only 1 with MFI >1500. A single infusion of third-party MSC following kidney transplantation appears to be safe, with one cardiac event of unclear relationship to the intervention. MSC therapy is associated with increased regulatory T cell proportion and with improved early allograft function. Long-term effects, including potential immunization against MSC, remain to be studied.

ispartof: JOURNAL OF NEPHROLOGY vol:34 issue:4 pages:967-969 ispartof: location:Italy status: published

Background and Aims Proteinuria, hematuria and acute kidney injury (AKI) are frequently observed in hospitalized patients with COVID-19. However, few data are available on these parameters after hospital discharge. Method This retrospective, observational and monocentric study included 153 hospitalized patients, in whom urine total proteinuria and α1-microglobulin (a marker of tubular injury) were measured. Thirty patients died. Among the 123 survivors, follow-up urine and creatinine analyses were available for 72 patients (after a median of 51 [19;93] days following hospital discharge). Results The median proteinuria at hospitalization and follow-up (n=72) was 419 [239; 748] and 79 [47; 129] mg/g, respectively (p15 mg/g (%) 88 29 Urine β2-microglobulin (n=60) (mg/L) 0.92 [0.41;4.52] 0.00 [0.00;0.00] 0.19 mg/L (%) 82 13 Hematuria (>10 per field) (%) (n=51) 19 12 ns

Background Proteinuria has been commonly reported in patients with COVID-19. However, only dipstick tests have been frequently used thus far. Here, the quantification and characterization of proteinuria were investigated and their association with mortality was assessed. Methods This retrospective, observational, single center study included 153 patients, hospitalized with COVID-19 between March 28th and April 30th, 2020, in whom total proteinuria and urinary α1-microglobulin (a marker of tubular injury) were measured. Association with mortality was evaluated, with a follow-up until May 7th, 2020. Results According to the Kidney Disease Improving Global Outcomes staging, 14% (n = 21) of the patients had category 1 proteinuria (1-microglobulin concentration was higher than 15 mg/g in 89% of patients. After a median follow-up of 27 [14;30] days, the mortality rate reached 18%. Total proteinuria and urinary α1-microglobulin were associated with mortality in unadjusted and adjusted models. This association was stronger in subgroups of patients with normal renal function and without a urinary catheter. Conclusions Proteinuria is frequent in patients with COVID-19. Its characterization suggests a tubular origin, with increased urinary α1-microglobulin. Tubular proteinuria was associated with mortality in COVID-19 in our restropective, observational study.

Background: Kidney damage has been reported in patients with COVID-19. Despite numerous reports about COVID-19-associated nephropathy, the factual presence of the SARS-CoV-2 in the renal parenchyma remains controversial. Methods: We consecutively performed 16 immediate (≤3h) post-mortem renal biopsies in patients diagnosed with COVID-19. Kidney samples from 5 patients who died from sepsis not related to COVID-19 were used as controls. Samples were methodically evaluated by 3 pathologists. Virus detection in the renal parenchyma was performed in all samples by bulk RNA RT-PCR (E and N1/N2 genes), immunostaining (nCoV2019 N-Protein), fluorescent in situ hybridization (nCoV2019-S) and electron microscopy. Results: The mean age of our COVID-19 cohort was 68.2±12.8 years, most of whom were males (68.7%). Proteinuria was observed in 53.3% of cases, while acute kidney injury occurred in 60% of cases. Acute tubular necrosis of variable severity was found in all cases, with no tubular or interstitial inflammation. There was no difference in acute tubular necrosis severity between the patients with COVID-19 versus controls. Congestion in glomerular and peri-tubular capillaries was respectively observed in 56.3 and 87.5% of patients with COVID-19 compared to 20% of controls, with no evidence of thrombi. The nCoV2019 N-Protein was detected in proximal tubules and also at the basolateral pole of scattered cells of the distal tubules in 9/16 cases. In situ hybridization confirmed these findings in 6/9 interpretable cases. RT-PCR of kidney total RNA detected SARS-CoV-2 E and N1/N2 genes in one case. Electron microscopy did not show typical viral inclusions. Conclusions: Our immediate post-mortem kidney samples from patients with COVID-19 highlight a congestive pattern of acute kidney injury, with no significant glomerular or interstitial inflammation. Immunostaining and in situ hybridization suggest that SARS-CoV-2 is present in various segments of the nephron.

Introduction La protéinurie serait fréquente chez les patients atteints de la COVID-19, ce qui suggère une atteinte rénale liée à cette infection. Cependant, ces résultats proviennent de l’analyse de bandelettes urinaires. Description Nous quantifions et caractérisons la protéinurie et nous investiguons son association potentielle avec la mortalité. Méthodes Cette étude rétrospective, observationnelle et monocentrique inclut 153 patients atteints de la COVID-19 (PCR + ) hospitalisés entre le 28 mars et le 30 avril 2020 et ayant bénéficié d’une quantification systématique de leur protéinurie totale ainsi que d’un dosage de l’α1-microglobuline urinaire. Nous testons l’association entre ces paramètres urinaires et la mortalité (fin du suivi en date du 7 mai 2020). Résultats Selon la classification KDIGO, 14 % (n = 21) des patients avaient une protéinurie normale ou de stade 1 ( 500 mg/g). La concentration urinaire en α1-microglobuline était supérieure à 10 et 15 mg/g de créatinine urinaire chez 94 % et 89 % des patients, respectivement. Après un suivi médian de 27 [14 ; 30] jours, le taux de mortalité était de 18 %. La protéinurie totale et l’α1-microglobuline urinaire (en tant que variables continues et/ou catégorielles) sont associées à la mortalité dans les modèles non ajustés (courbes de survie selon Kaplan–Meier en Fig. 1) et ajustés. Cette association est encore plus significative dans les sous-groupes de patients avec une fonction rénale initialement normale ou sans sondage urinaire durant l’hospitalisation. Conclusion La protéinurie est fréquente chez les patients atteints de la COVID-19. Sa caractérisation suggère une atteinte préférentiellement tubulaire. Les protéinuries totale et tubulaire sont associées à la mortalité.

Renal segmental metabolism is reflected by the complex distribution of the main energy pathways along the nephron, with fatty acid oxidation preferentially used in the cortex area. Ischemia/reperfusion injury (IRI) is due to the restriction of renal blood flow, rapidly leading to a metabolic switch toward anaerobic conditions. Subsequent unbalance between energy demand and oxygen/nutrient delivery compromises kidney cell functions, resulting in a complex inflammatory cascade including the production of reactive oxygen species (ROS). Renal IRI especially involves lipid accumulation. Lipid peroxidation is one of the major events of ROS-associated tissue injury. Here, we briefly review the current knowledge of renal cell lipid metabolism in normal and ischemic conditions. Next, we focus on renal lipid-associated injury, with emphasis on its mechanisms and consequences during the course of IRI. Finally, we discuss preclinical observations aiming at preventing and/or attenuating lipid-associated IRI.

Introduction Une atteinte renale, tubulaire et/ou glomerulaire, a ete suggeree dans le cadre de la COVID-19, nouvelle entite causee par le coronavirus SARS-CoV-2. Cependant, l’aspect histologique de cette nephropathie est peu documente. Description Entre le 30 mars 2020 et le 4 juin 2020, nous avons realise systematiquement une biopsie renale post-mortem chez tout patient decede dans le cadre d’une COVID-19 en salle d’hospitalisation ou aux soins intensifs. Methodes Notre etude se focalise sur la correlation anatomoclinique de l’atteinte renale de la COVID-19. Resultats L’âge moyen de notre population (n = 16) est de 68,2 ± 12,8 ans avec une predominance masculine (68,7 %). L’indice de masse corporelle moyen est de 30,7 ± 6,1 kg/m2. L’hypertension, le diabete et l’insuffisance renale chronique sont respectivement presents dans 62,5 %, 56,3 % et 42,9 % des patients. La duree mediane d’hospitalisation avant le deces est de 14 jours [7,5 ; 25,5]. Les biopsies renales ont ete effectuees aux soins intensifs dans 62,5 % des cas. La prevalence de l’insuffisance renale aigue est de ∼50 % des cas, avec 53,3 % des patients presentant a l’admission une proteinurie > 500 mg/g de creatinine urinaire ( Tableau 1 ). Les analyses histologiques demontrent en microscopie optique, une necrose tubulaire aigue de severite legere (70 % des cas) sans inclusion virale objectivee, et l’absence d’un infiltrat interstitiel ou de tubulite. Une congestion capillaire glomerulaire et peri-tubulaire est objectivee dans respectivement 53,3 % et 80 % des cas. La microscopie electronique chez un patient montre des images compatibles avec la presence d’inclusions virales dans le cytoplasme des cellules endotheliales des capillaires glomerulaires (en cours de confirmation par immunogold). Conclusion L’analyse histologique renale post-mortem de patients atteints de la COVID-19 montre principalement des lesions tubulaires sans lesion glomerulaire significative malgre la presence d’une atteinte renale biologique ou urinaire dans ∼50 % des cas. Une correlation anatomoclinique est essentielle pour evaluer l’atteinte renale directe ou non par le virus.

Ischemia/reperfusion injury (IRI) represents a worldwide public health issue of increasing incidence. IRI may virtually affect all organs and tissues and is associated with significant morbidity and mortality. Particularly, the duration of blood supply deprivation has been recognized as a critical factor in stroke, hemorrhagic shock, or myocardial infarction, as well as in solid organ transplantation (SOT). Pathophysiologically, IRI causes multiple cellular and tissular metabolic and architectural changes. Furthermore, the reperfusion of ischemic tissues induces both local and systemic inflammation. In the particular field of SOT, IRI is an unavoidable event, which conditions both short- and long-term outcomes of graft function and survival. Clinically, the treatment of patients with IRI mostly relies on supportive maneuvers since no specific target-oriented therapy has been validated thus far. In the present review, we summarize the current literature on mesenchymal stromal cells (MSC) and their potential use as cell therapy in IRI. MSC have demonstrated immunomodulatory, anti-inflammatory, and tissue repair properties in rodent studies and in preliminary clinical trials, which may open novel avenues in the management of IRI and SOT.

Background. Mesenchymal stromal cells (MSC) are fibroblast-like multipotent cells capable of tissue-repair properties. Given the essentiality of tight junctions (TJ) in epithelial integrity, we hypothesized that MSC modulate TJ formation, via the AMP-activated kinase (AMPK) pathway. Liver kinase-β1 (LKB1) and Ca2+-calmodulin-dependent protein kinase kinase (CaMKK) represent the main kinases that activate AMPK.Methods. The in vitro Ca2+switch from 5 μM to 1.8 mM was performed using epithelial Madin-Darby canine kidney (MDCK) cells cultured alone or cocultured with rat bone marrow-derived MSC or preexposed to MSC-conditioned medium. TJ assembly was measured by assessing ZO-1 relocation to cell-cell contacts. Experiments were conducted using MDCK stably expressing short-hairpin-RNA (shRNA) against LKB1 or luciferase (LUC, as controls). Compound STO-609 (50 μM) was used as CaMKK inhibitor.Results. Following Ca2+switch, ZO-1 relocation and phosphorylation/activation of AMPK were significantly higher in MDCK/MSC compared to MDCK. No difference in AMPK phosphorylation was observed between LKB1-shRNA and Luc-shRNA MDCK following Ca2+switch. Conversely, incubation with STO-609 prior to Ca2+switch prevented AMPK phosphorylation and ZO-1 relocation. MSC-conditioned medium slightly but significantly increased AMPK activation and accelerated TJ-associated distribution of ZO-1 post Ca2+switch in comparison to regular medium.Conclusions. MSC modulate the assembly of epithelial TJ, via the CaMKK/AMPK pathway independently of LKB1.

Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis is an autosomal-recessive disease caused by mutations in the CLDN16 or CLDN19 genes, which encode tight junction-associated proteins, claudin-16 and -19. The resultant tubulopathy leads to urinary loss of Mg(2+) and Ca(2+), with subsequent nephrocalcinosis and end-stage renal disease (ESRD). An 18-year-old boy presented with chronic kidney disease and proteinuria, as well as hypomagnesaemia, hypercalciuria and nephrocalcinosis. A kidney biopsy revealed tubular atrophy, interstitial fibrosis and segmental sclerosis of some glomeruli. Two novel mutations in the CLDN16 gene were identified: c.340C>T (nonsense) and c.427+5G>A (splice site). The patient reached ESRD at 23 and benefited from kidney transplantation.

Kidney transplantation represents the best treatment of end-stage renal disease. In addition to the degree of human leukocyte antigen matching, long-term graft survival is influenced by the quality of the graft before its transplantation. Quality criteria include the level of ischemic damage caused by the transplantation per se. Renal ischemic preconditioning (IP) consists of different approaches to prevent ischemia/reperfusion (I/R) damage induced by the interruption and recovery of renal circulation, as observed during transplantation. Distinct animal models show promising results regarding the efficiency of PCI to preserve kidney structure and function in I/R conditions. Characterizing the cellular cascades involved in I/R led to the identification of putative targets of renal IP, including the adenosine monophosphate-activated protein kinase (AMPK). AMPK is a ubiquitous energy sensor, which has been implicated in the maintenance of epithelial cell polarization under energy deprivation. Among others, the anti-diabetic drug, metformin, is a potent activator of AMPK. Here, we summarize the in vitro and in vivo data about the role of AMPK in renal IP. Defining the pharmacological conditions of IP would help to improve the quality of the renal graft before its transplantation, thereby increasing its long-term survival.

Mesenchymal stromal cells (MSC) have been demonstrated to attenuate renal ischemia/reperfusion (I/R) damage in rodent models. The mechanisms of such nephro-protection remain largely unknown. Furthermore, the optimal timing of MSC administration has been poorly investigated. Here, we compare the impact of MSC injection 7 days before (MSCD − 7) versus 1 day after (MSCD + 1) renal I/R in rats. Control groups received equivalent volumes of saline at similar time-points (SD − 7 and SD + 1). Right nephrectomy was performed, and left renal ischemia lasted 45 min. After 48-hour reperfusion, we observed significantly improved renal function parameters, reduced apoptotic index and neutrophil/macrophage infiltration in kidney parenchyma, and lower expression of tubular damage markers and pro-inflammatory cytokines in MSCD − 7 in comparison to MSCD + 1 and saline control groups. Next, comparative high-throughput RNA sequencing of MSCD − 7 vs. SD − 7 non-ischemic right kidneys highlighted significant down-regulation of fatty acid biosynthesis and up-regulation of PPAR-α pathway. Such a preferential regulation towards lipid catabolism was associated with decreased levels of lipid peroxidation products, i.e. malondialdehyde and 4-hydroxy-2-nonenal, in MSCD − 7 versus SD − 7 ischemic kidneys. Our findings suggest that MSC pretreatment may exert protective effects against renal I/R by modulating lipid metabolism in rats.

Acute kidney injury (AKI) represents a worldwide public health issue of increasing incidence, with a significant morbimortality. AKI treatment mostly relies on supportive manoeuvres in the absence of specific target-oriented therapy. The pathophysiology of AKI commonly involves ischaemia/reperfusion (I/R) events, which cause both immune and metabolic consequences in renal tissue. Similarly, at the time of kidney transplantation (KT), I/R is an unavoidable event which contributes to early graft dysfunction and enhanced graft immunogenicity. Mesenchymal stromal cells (MSCs) represent a heterogeneous population of adult, fibroblast-like multi-potent cells characterized by their ability to differentiate into tissues of mesodermal lineages. Because MSC have demonstrated immunomodulatory, anti-inflammatory and tissue repair properties, MSC administration at the time of I/R and/ or at later times has been hypothesized to attenuate AKI severity and to accelerate the regeneration process. Furthermore, MSC in KT could help prevent both I/R injury and acute rejection, thereby increasing graft function and survival. In this review, summarizing the encouraging observations in animal models and in pilot clinical trials, we outline the benefi to f MSC therapy in AKI and KT, and envisage their putative role in renal ischaemic conditioning.

The diagnosis of acute rejection still relies on renal allograft biopsy. In fact, histological features including C4d staining can be useful to differentiate cellular and antibody-mediated acute rejection. However, the pathogenic mechanism to define the type of rejection is usually assessed by anti-HLA donor specific antibodies (DSA) monitoring. Suspicion of acute rejection is usually based on renal function deterioration. This method has low sensitivity. Moreover, creatinine increase follows graft injury and therefore the diagnosis is performed when there is an ongoing acute rejection. One strategy to overcome the limitation of serum creatinine as predictor of acute rejection is to perform surveillance protocol biopsies. However, the low incidence of subclinical acute rejection among patients treated with tacrolimus-based immunosuppression makes this procedure questionable in terms of cost-effectiveness. In this scenario new biomarkers predicting acute rejection are urgently needed. Ideally, such biomarkers should anticipate acute rejection, thus allowing preventive actions such as maintenance immunosupression intensification and/or modification. Alternatively, these new biomarkers should at least improve the predictive value of serum creatinine monitoring. Although many of the new biomarkers are promising, none have been translated to the clinic to date because of a lack of validation studies and the existence of major methodological concerns.

Kidney transplantation (KTx) represents the best available treatment for patients with end-stage renal disease. Still, full benefits of KTx are undermined by acute rejection (AR). The diagnosis of AR ultimately relies on transplant needle biopsy. However, such an invasive procedure is associated with a significant risk of complications and is limited by sampling error and interobserver variability. In the present review, we summarize the current literature about non-invasive approaches for the diagnosis of AR in kidney transplant recipients (KTRs), including in vivo imaging, gene expression profiling and omics analyses of blood and urine samples. Most imaging techniques, like contrast-enhanced ultrasound and magnetic resonance, exploit the fact that blood flow is significantly lowered in case of AR-induced inflammation. In addition, AR-associated recruitment of activated leukocytes may be detectable by 18F-fluoro-deoxy-glucose positron emission tomography. In parallel, urine biomarkers, including CXCL9/CXCL10 or a three-gene signature of CD3e, IP-10 and 18S RNA levels, have been identified. None of these approaches has been adopted yet in the clinical follow-up of KTRs, but standardization of procedures may help assess reproducibility and compare diagnostic yields in large prospective multicentric trials.