Corrigendum: Ex vivo normothermic preservation of a kidney graft from uncontrolled donation after circulatory death over 73 hours

[This corrects the article DOI: 10.3389/fbioe.2023.1330043.].

Phase variation modulates the multi-phenotypes displayed by clinical Campylobacter jejuni strains

The high incidence and prevalence of Campylobacter spp. in the food supply chain entail the importance to understand their mechanisms developed to withstand harsh environmental conditions encountered. Different stress conditions and phenotypic approaches were evaluated to study the behaviour of five clinical C. jejuni isolates with different genotypes, including the tolerance to oxygen and the oxidants hydrogen peroxide and cumene hydroperoxide, the motility and the ability to form biofilm on polystyrene and stainless steel at different temperatures and atmospheres. Whole Genome Sequencing was performed to analyse the occurrence of 216 genes involved in these mechanisms plus phase variation. The isolates showed high tolerance to oxygen and peroxide stress with different swimming motility performances and biofilm formation abilities. Aerotolerance was related with a reduced sensitive to peroxide stress and a loss of motility that promotes biofilm formation depending on the material surface. Comparative genomics did not reveal any clear gene pattern, although phase variation occurring during host infection was observed to be crucial for the modulation of the different survival mechanisms adopted by the bacteria. These findings reveal that the bacteria can combine diverse and complex strategies in an efficient manner to survive and persist in the environment.

Ex vivo normothermic preservation of a kidney graft from uncontrolled donation after circulatory death over 73 hours

The transplant community is focused on prolonging the ex vivo preservation time of kidney grafts to allow for long-distance kidney graft transportation, assess the viability of marginal grafts, and optimize a platform for the translation of innovative therapeutics to clinical practice, especially those focused on cell and vector delivery to organ conditioning and reprogramming. We describe the first case of feasible preservation of a kidney from a donor after uncontrolled circulatory death over a 73-h period using normothermic perfusion and analyze hemodynamic, biochemical, histological, and transcriptomic parameters for inflammation and kidney injury. The mean pressure and flow values were 71.24 ± 9.62 mmHg and 99.65 ± 18.54 mL/min, respectively. The temperature range was 36.7°C-37.2°C. The renal resistance index was 0.75 ± 0.15 mmHg/mL/min. The mean pH was 7.29 ± 0.15. The lactate concentration peak increased until 213 mg/dL at 6 h, reaching normal values after 34 h of perfusion (8.92 mg/dL). The total urine output at the end of perfusion was 1.185 mL. Histological analysis revealed no significant increase in acute tubular necrosis (ATN) severity as perfusion progressed. The expression of KIM-1, VEGF, and TGFβ decreased after 6-18 h of perfusion until 60 h in which the expression of these genes increased again together with the expression of β-catenin, Ki67, and TIMP1. We show that normothermic perfusion can maintain a kidney graft viable ex vivo for 3 days, thus allowing a rapid translation of pre-clinical therapeutics to clinical practice.

Early kinetics of donor-derived cell-free DNA after transplantation predicts renal graft recovery and long-term function

BACKGROUND

Ischemia-reperfusion injury (IRI) upon transplantation is one of the most impactful events that the kidney graft suffers during its life. Its clinical manifestation in the recipient, delayed graft function (DGF), has serious prognostic consequences. However, the different definitions of DGF are subject to physicians' choices and centers' policies, and a more objective tool to quantify IRI is needed. Here, we propose the use of donor-derived cell-free DNA (ddcfDNA) for this scope.

METHODS

ddcfDNA was assessed in 61 kidney transplant recipients of either living or deceased donors at 24 h, and 7, 14 and 30 days after transplantation using the AlloSeq cfDNA Kit (CareDx, San Francisco, CA, USA). Patients were followed-up for 6 months and 7-year graft survival was estimated through the complete and functional iBox tool.

RESULTS

Twenty-four-hour ddcfDNA was associated with functional DGF [7.20% (2.35%-15.50%) in patients with functional DGF versus 2.70% (1.55%-4.05%) in patients without it, P = .023] and 6-month estimated glomerular filtration rate (r = -0.311, P = .023). At Day 7 after transplantation, ddcfDNA was associated with dialysis duration in DGF patients (r = 0.612, P = .005) and worse 7-year iBox-estimated graft survival probability (β -0.42, P = .001) at multivariable analysis. Patients with early normalization of ddcfDNA (<0.5% at 1 week) had improved functional iBox-estimated probability of graft survival (79.5 ± 16.8%) in comparison with patients with 7-day ddcfDNA ≥0.5% (67.7 ± 24.1%) (P = .047).

CONCLUSIONS

ddcfDNA early kinetics after transplantation reflect recovery from IRI and are associated with short-, medium- and long-term graft outcome. This may provide a more objective estimate of IRI severity in comparison with the clinical-based definitions of DGF.

Chimeric HLA antibody receptor T cells for targeted therapy of antibody-mediated rejection in transplantation

The presence of donor-specific antibodies (DSA), mainly against HLA, increases the risk of allograft rejection. Moreover, antibody-mediated rejection (ABMR) remains an important barrier to optimal long-term outcomes after solid organ transplantation. The development of chimeric autoantibody receptor T lymphocytes has been postulated for targeted therapy of autoimmune diseases. We aimed to develop a targeted therapy for DSA desensitization and ABMR, generating T cells with a chimeric HLA antibody receptor (CHAR) that specifically eliminates DSA-producing B cells. We have genetically engineered an HLA-A2-specific CHAR (A2-CHAR) and transduced it into human T cells. Then, we have performed in vitro experiments such as cytokine measurement, effector cell activation, and cytotoxicity against anti-HLA-A2 antibody-expressing target cells. In addition, we have performed A2-CHAR-Tc cytotoxic assays in an immunodeficient mouse model. A2-CHAR expressing T cells could selectively eliminate HLA-A2 antibody-producing B cells in vitro. The cytotoxic capacity of A2-CHAR expressing T cells mainly depended on Granzyme B release. In the NSG mouse model, A2-CHAR-T cells could identify and eradicate HLA-A2 antibody-producing B cells even when those cells are localized in the bone marrow. This ability is effector:target ratio dependent. CHAR technology generates potent and functional human cytotoxic T cells to target alloreactive HLA class I antibody-producing B cells. Thus, we consider that CHAR technology may be used as a selective desensitization protocol or an ABMR therapy in transplantation.

From systemic lupus erythematosus to lupus nephritis: The evolving road to targeted therapies

Systemic lupus erythematosus is a chronic autoimmune disease characterized by loss of tolerance against nuclear and cytoplasmic self-antigens, induction of immunity and tissue inflammation. Lupus nephritis (LN), the most important predictor of morbidity in SLE, develops in almost 30% of SLE patients at disease onset and in up to 50-60% within the first 10 years. Firstly, in this review, we put the pathogenic mechanisms of the disease into a conceptual frame, giving emphasis to the role of the innate immune system in this loss of self-tolerance and the induction of the adaptive immune response. In this aspect, many mechanisms have been described such as dysregulation and acceleration of cell-death pathways, an aberrant clearance and overload of immunogenic acid-nucleic-containing debris and IC, and the involvement of antigen-presenting cells and other innate immune cells in the induction of this adaptive immune response. This result in a clonal expansion of autoreactive lymphocytes with generation of effector T-cells, memory B-cells and plasma cells that produce autoantibodies that will cause kidney damage. Secondly, we review the immunological pathways of damage in the kidney parenchyma, initiated by autoantibody binding and immune complex deposition, and followed by complement-mediated microvascular injury, activation of kidney stromal cells and the recruitment of leukocytes. Finally, we summarize the rationale for the treatment of LN, from conventional to new targeted therapies, focusing on their systemic immunologic effects and the minimization of podocytary damage.

Physiopathological role of extracellular vesicles in alloimmunity and kidney transplantation and their use as biomarkers

Antibody-mediated rejection is the leading cause of kidney graft dysfunction. The process of diagnosing it requires the performance of an invasive biopsy and subsequent histological examination. Early and sensitive biomarkers of graft damage and alloimmunity are needed to identify graft injury and eventually limit the need for a kidney biopsy. Moreover, other scenarios such as delayed graft function or interstitial fibrosis and tubular atrophy face the same problem. In recent years, interest has grown around extracellular vesicles, specifically exosomes actively secreted by immune cells, which are intercellular communicators and have shown biological significance. This review presents their potential as biomarkers in kidney transplantation and alloimmunity.

Genomic Characterization of Campylobacter jejuni Associated with Perimyocarditis: A Family Case Report

Campylobacter spp. is the leading cause of foodborne gastrointestinal infections in humans worldwide. This study reports the first case of four family members who had contact with the same source of Campylobacter jejuni contamination with different results. Only the little siblings were infected by the same C. jejuni strain, but with different symptoms. Whereas the daughter was slightly affected with mild enteritis, the son suffered a longer campylobacteriosis followed with a perimyocarditis. This is the first case of the youngest patient affected by C. jejuni-related perimyocarditis published to date. The genomes of both strains were characterized by whole-genome sequencing and compared with the C. jejuni NCTC 11168 genome to gain insights into the molecular features that may be associated with perimyocarditis. Various comparison tools were used for the comparative genomics analysis, including the identification of virulence and antimicrobial resistance genes, phase variable (PV) genes, and single nucleotide polymorphisms (SNPs) identification. Comparisons of the strains identified 16 SNPs between them, which constituted small but significant changes mainly affecting the ON/OFF state of PV genes after passing through both hosts. These results suggest that PV occurs during human colonization, which modulates bacteria virulence through human host adaptation, which ultimately is related to complications after a campylobacteriosis episode depending on the host status. The findings highlight the importance of the relation between host and pathogen in severe complications of Campylobacter infections.

CamPype: an open-source workflow for automated bacterial whole-genome sequencing analysis focused on Campylobacter

BACKGROUND

The rapid expansion of Whole-Genome Sequencing has revolutionized the fields of clinical and food microbiology. However, its implementation as a routine laboratory technique remains challenging due to the growth of data at a faster rate than can be effectively analyzed and critical gaps in bioinformatics knowledge.

RESULTS

To address both issues, CamPype was developed as a new bioinformatics workflow for the genomics analysis of sequencing data of bacteria, especially Campylobacter, which is the main cause of gastroenteritis worldwide making a negative impact on the economy of the public health systems. CamPype allows fully customization of stages to run and tools to use, including read quality control filtering, read contamination, reads extension and assembly, bacterial typing, genome annotation, searching for antibiotic resistance genes, virulence genes and plasmids, pangenome construction and identification of nucleotide variants. All results are processed and resumed in an interactive HTML report for best data visualization and interpretation.

CONCLUSIONS

The minimal user intervention of CamPype makes of this workflow an attractive resource for microbiology laboratories with no expertise in bioinformatics as a first line method for bacterial typing and epidemiological analyses, that would help to reduce the costs of disease outbreaks, or for comparative genomic analyses. CamPype is publicly available at https://github.com/JoseBarbero/CamPype .

High-Intensity Exercise Promotes Deleterious Cardiovascular Remodeling in a High-Cardiovascular-Risk Model: A Role for Oxidative Stress

Although the benefits of moderate exercise in patients at high cardiovascular risk are well established, the effects of strenuous exercise remain unknown. We aimed to study the impact of strenuous exercise in a very high cardiovascular risk model. Nephrectomized aged Zucker obese rats were trained at a moderate (MOD) or high (INT) intensity or were kept sedentary (SED) for 10 weeks. Subsequently, echocardiography and ex vivo vascular reactivity assays were performed, and blood, aortas, perivascular adipose tissue (PVAT), and left ventricles (LVs) were harvested. An improved risk profile consisting of decreased body weight and improved response to a glucose tolerance test was noted in the trained groups. Vascular reactivity experiments in the descending thoracic aorta demonstrated increased endothelial NO release in the MOD group but not in the INT group, compared with SED; the free radical scavenger TEMPOL improved endothelial function in INT rats to a similar level as MOD. An imbalance in the expression of oxidative stress-related genes toward a pro-oxidant environment was observed in the PVAT of INT rats. In the heart, INT training promoted eccentric hypertrophy and a mild reduction in ejection fraction. Obesity was associated with LV fibrosis and a transition toward β-myosin heavy chain and the N2Ba titin isoform. Exercise reverted the myosin imbalance, but only MOD reduced the predominance of the N2Ba titin isoform. In conclusion, moderate exercise yields the most intense cardiovascular benefits in a high-cardiovascular-risk animal model, while intense training partially reverts them.

Extracorporeal Photopheresis Improves Graft Survival in a Full-Mismatch Rat Model of Kidney Transplantation

Extracorporeal photopheresis (ECP) is an immunomodulatory therapy based on the infusion of autologous cellular products exposed to ultraviolet light (UV) in the presence of a photosensitizer. The study evaluates the ECP efficacy as induction therapy in a full-mismatch kidney transplant rat model. Dark Agouti to Lewis (DA-L) kidney transplant model has been established. ECP product was obtained from Lewis rat recipients after DA kidney graft transplantation (Lew^DA). Leukocytes of those Lew^DA rats were exposed to 8-methoxy psoralen, and illuminated with UV-A. The ECP doses assessed were 10 × 10⁶ and 100 × 10⁶ cells/time point. Lewis recipients received seven ECP infusions. DA-L model was characterized by the appearance of donor-specific antibodies (DSA) and kidney function deterioration from day three after kidney transplant. The dysfunction progressed rapidly until graft loss (6.1 ± 0.5 days). Tacrolimus at 0.25 mg/kg prolonged rat survival until 11.4 ± 0.7 days (p = 0.0004). In this context, the application of leukocytes from LewDA sensitized rats accelerated the rejection (8.7 ± 0.45, p = 0.0012), whereas ECP product at high dose extended kidney graft survival until 26.3 ± 7.3 days, reducing class I and II DSA in surviving rats. ECP treatment increases kidney graft survival in full-mismatch rat model of acute rejection and is a suitable immunomodulatory therapy to be explored in kidney transplantation.

Immune Profiling of Peripheral Blood Mononuclear Cells at Pancreas Acute Rejection Episodes in Kidney-Pancreas Transplant Recipients

Profiling of circulating immune cells provides valuable insight to the pathophysiology of acute rejection in organ transplantation. Herein we characterized the peripheral blood mononuclear cells in simultaneous kidney-pancreas transplant recipients. We conducted a retrospective analysis in a biopsy-matched cohort (n = 67) and compared patients with biopsy proven acute rejection (BPAR; 41%) to those without rejection (No-AR). We observed that CD3+ T cells, both CD8+ and CD4+, as well as CD19+ B cells were increased in patients with BPAR, particularly in biopsies performed in the early post-transplant period (<3 months). During this period immune subsets presented a good discriminative ability (CD4+ AUC 0.79; CD8+ AUC 0.80; B cells AUC 0.86; p < 0.05) and outperformed lipase (AUC 0.62; p = 0.12) for the diagnosis of acute rejection. We further evaluated whether this could be explained by differences in frequencies prior to transplantation. Patients presenting with early post-transplant rejection (<3 months) had a significant increase in T-cell frequencies pre-transplant, both CD4+ T cells and CD8+ T cells (p < 0.01), which were associated with a significant inferior rejection-free graft survival. T cell frequencies in peripheral blood correlated with pancreas acute rejection episodes, and variations prior to transplantation were associated with pancreas early acute rejection.

High intensity exercise improves the metabolic syndrome in an aged murine model, but it abrogates the vascular function improvement induced by moderate exercise

Introduction

Compelling evidence supports that regular moderate exercise has a positive impact on cardiovascular disease (CVD) incidence and prognosis [1]. Nevertheless, emerging clinician and experimental data in healthy individuals suggests that long-term, high-intensity endurance exercise might increase vascular stiffness and enhance coronary calcification [2,3]. In patients with CV risk factors, it has been hypothesized that the beneficial effects of strenuous exercise on risk factors could outweigh its deleterious effects, but this remains unproven [4].

Purpose

To analyze how increasing doses of exercise impinge on the vascular system in a murine model of aged rats with metabolic syndrome and kidney disease.

Methods

Seven-week-old male Zucker obese rats, a metabolic syndrome model, were subjected to left nephrectomy. At 26 weeks of age, rats were assigned to a sedentary (SED), moderate intensity (MOD, 15 cm/s, 40 min/day), or high intensity (INT, 25 cm/s, 60 min/day) group, and trained 5 days/week for 10 weeks. An echocardiogram and a glucose tolerance test were performed 24 hours after the last training bout. At sacrifice, vascular reactivity was assayed in the descending thoracic aorta, and EC50 calculated for every experiment. Expression of oxidant and antioxidant mRNA markers was analyzed in thoracic perivascular adipose tissue (tPVAT). Cytokines levels (TNFα, IL10, IL6, Selectin, ICAM1 and Adiponectin) were analyzed in plasma samples.

Results

Rats in the INT group had a significantly lower body weight (10.99±0.35 g/mm vs 12.23±0.58 g/mm) and a higher heart weight (32.44±0.72 mg/mm vs 31.28±0.78 mg/mm), indexed by tibia length, than the SED group. Both MOD and INT exercise improved glucose tolerance compared with SED (Fig 1a). On echocardiography, INT rats presented with LV septum hypertrophy and dilation, mildly reduced ejection fraction and fractional shortening compared with SED. Aortic diameter was also increased in the INT group (3.62±0.11 mm vs 3.25±0.13 mm). In vascular reactivity assays, the MOD group showed improved endothelial function, indicated by a larger carbachol-induced relaxation than SED and INT (Fig. 1b). However, MOD and INT were no longer different after adding the antioxidant Tempol (Fig1c). No differences were found in tunica media fibrosis amongst the groups (19.12±0.45%; 26.97±2.52%; 25.98±2.14%). In tPVAT, the mRNA expression of prooxidants (NOX2, p47) was higher, and antioxidant markers (SOD2, GCH1) was lower in the INT group than MOD and SED (Fig. 2). TNFα levels were higher in plasma of INT rats than SED.

Conclusion

In a rodent model, both intense and moderate exercise improved the CV risk profile, but only moderate training improved vascular function. Oxidative stress may, at least partially, account for the lack of benefits of intensive exercise. Our results suggest that the deleterious effects of strenuous physical activity could persist even in individuals with CV risk factor.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fondo de Investigaciόn Sanitaria (FIS), Instituto de Salud Carlos III

Non-linear models for black carbon exposure modelling using air pollution datasets

Black carbon (BC) is a product of incomplete combustion, present in urban aerosols and sourcing mainly from road traffic. Epidemiological evidence reports positive associations between BC and cardiovascular and respiratory disease. Despite this, BC is currently not regulated by the EU Air Quality Directive, and as a result BC data are not available in urban areas from reference air quality monitoring networks in many countries. To fill this gap, a machine learning approach is proposed to develop a BC proxy using air pollution datasets as an input. The proposed BC proxy is based on two machine learning models, support vector regression (SVR) and random forest (RF), using observations of particle mass and number concentrations (N), gaseous pollutants and meteorological variables as the input. Experimental data were collected from a reference station in Barcelona (Spain) over a 2-year period (2018-2019). Two months of additional data were available from a second urban site in Barcelona, for model validation. BC concentrations estimated by SVR showed a high degree of correlation with the measured BC concentrations (R² = 0.828) with a relatively low error (RMSE = 0.48 μg/m³). Model performance was dependent on seasonality and time of the day, due to the influence of new particle formation events. When validated at the second station, performance indicators decreased (R² = 0.633; RMSE = 1.19 μg/m³) due to the lack of N data and PM_2.5 and the smaller size of the dataset (2 months). New particle formation events critically impacted model performance, suggesting that its application would be optimal in environments where traffic is the main source of ultrafine particles. Due to its flexibility, it is concluded that the model can act as a BC proxy, even based on EU-regulatory air quality parameters only, to complement experimental measurements for exposure assessment in urban areas.

Easy Nitrite Analysis of Processed Meat with Colorimetric Polymer Sensors and a Smartphone App

We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric film-shaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by only taking digital photographs of sensory films and analyzing digital color parameters. The film-shaped polymer sensor detects nitrite anions by an azo-coupling reaction, since they activate this reaction between two of the four monomers that the copolymer is based on. The sensory polymer is complemented with an app, which analyzes the color in two different digital color spaces (RGB and HSV) and performs a set of 32 data fittings representing the concentration of nitrite versus eight different variables, finally providing the nitrite concentration of the test samples using the best fitting curve. The calculated concentration of nitrite correlates with a validated method (ISO 2918: 1975) usually used to determine nitrite, and no statistically significant difference between these methods and our proposed one has been found in our study (26 meat samples, 8 prepared, and 18 commercial). Our method represents a great advance in terms of analysis time, simplicity, and orientation to use by average citizens.

Donor-derived Cell-free DNA Shows High Sensitivity for the Diagnosis of Pancreas Graft Rejection in Simultaneous Pancreas-kidney Transplantation

BACKGROUND

Pancreas graft status in simultaneous pancreas-kidney transplant (SPKTx) is currently assessed by nonspecific biochemical markers, typically amylase or lipase. Identifying a noninvasive biomarker with good sensitivity in detecting early pancreas graft rejection could improve SPKTx management.

METHODS

Here, we developed a pilot study to explore donor-derived cell-free DNA (dd-cfDNA) performance in predicting biopsy-proven acute rejection (P-BPAR) of the pancreas graft in a cohort of 36 SPKTx recipients with biopsy-matched plasma samples. dd-cfDNA was measured using the Prospera test (Natera, Inc.) and reported both as a fraction of the total cfDNA (fraction; %) and as concentration in the recipient's plasma (quantity; copies/mL).

RESULTS

In the absence of P-BPAR, dd-cfDNA was significantly higher in samples collected within the first 45 d after SPKTx compared with those measured afterward (median, 1.00% versus 0.30%; median, 128.2 versus 35.3 cp/mL, respectively with both; P  = 0.001). In samples obtained beyond day 45, P-BPAR samples presented a significantly higher dd-cfDNA fraction (0.83 versus 0.30%; P  = 0.006) and quantity (81.3 versus 35.3 cp/mL; P  = 0.001) than stable samples. Incorporating dd-cfDNA quantity along with dd-cfDNA fraction outperformed dd-cfDNA fraction alone to detect active rejection. Notably, when using a quantity cutoff of 70 cp/mL, dd-cfDNA detected P-BPAR with a sensitivity of 85.7% and a specificity of 93.7%, which was more accurate than current biomarkers (area under curve of 0.89 for dd-cfDNA (cp/ml) compared with 0.74 of lipase and 0.46 for amylase).

CONCLUSIONS

dd-cfDNA measurement through a simple noninvasive blood test could be incorporated into clinical practice to help inform graft management in SPKTx patients.

FC002: Humoral and Cellular Immune Responses After a Three-Dose Course of Mrna-1273 Covid-19 Vaccine in Kidney Transplant Recipients: A Prospective Cohort Study

BACKGROUND AND AIMS

Seroconversion after a two-dose course of mRNA COVID-19 vaccination in kidney transplant recipients ranges between 30% and 50% in different series. We previously demonstrated that a substantial proportion of patients (35%) without a humoral response, develop a cellular response after the second dose assessed by the ELISpot technique. We aim to study the evolution of both humoral and cellular responses in the same cohort before and 1 month after the administration of the third dose of 100 mcg of mRNA-1273 COVID-19 vaccine.

METHOD

Final population included 129 KTRs studied at four time-points: at baseline before the first dose, after the second dose (median 42 days) and before (203 days) and after (232 days) the third dose. At all the time-points, IgG and IgM were assessed as well as N- and S-protein specific ELISpot. The main outcome was seroconversion after the third dose.

RESULTS

After the second dose, 26.7% of naïve cases experienced seroconversion. Before the third dose and in the absence of clinically evident COVID-19, this percentage increased to 61.9%. After the third dose, seroconversion was observed in 80.0% of patients. S-ELISpot positivity after the second dose was significantly associated with final seroconversion [OR (95% CI) 3.14 (1.10–8.96); P = .032], while transplantation &lt; 1 year and previous kidney transplant were negatively associated with [OR (95% CI) 0.23 (0.07–0.80); P = .021 and OR (95% CI) 0.22 (0.06–0.78); P = .020, respectively). IgG after third dose were significantly higher (P &lt; .001) in patients who maintained S-ELISpot positivity throughout the study (34.3%) and were correlated with S-spots after the second dose (r = 0.344, P &lt; .001).

CONCLUSION

A substantial proportion of KTRs vaccinated with mRNA-1273 develops a late seroconversion after two doses and only a fifth remained seronegative after a third. Cellular immunity seems to play a major role in the development of a final strong humoral response.

Immunogenic and immunotolerogenic effects of extracorporeal photopheresis in high immunological risk kidney recipients. A single center case series

The immunomodulatory effects of extracorporeal photopheresis (ECP) have been used for the treatment of T-cell mediated disorders, such as rejection in organ transplantation. Currently, it is an established therapy for heart and lung rejection, but not for kidney transplantation (KT), where experience is limited. In addition, some data suggest that ECP could generate an immune response against infections, thus being an alternative for the treatment of rejection in case of active or high-risk of infection. In the present study, we analyze four cases of use of ECP as concomitant therapy in patients with KT and high risk of opportunistic infections due to the high burden of immunosuppression throughout their renal diseases. Two patients had concomitant viral infection (cytomegalovirus and BK virus, respectively) and three patients were on treatment for graft rejection. In the two patients with active viral infection, the infection was successfully controlled during ECP treatment. In all cases, ECP has been shown to be a safe procedure, without complications.

B Cell-Derived Extracellular Vesicles Reveal Residual B Cell Activity in Kidney Graft Recipients Undergoing Pre-Transplant Desensitization

Background: Living-donor kidney transplant (LDKT) recipients undergoing desensitization for Human Leukocyte Antigen (HLA)-incompatibility have a high risk of developing antibody-mediated rejection (ABMR). The purpose of the study is to evaluate if residual B cell activity after desensitization could be estimated by the presence of circulating B cell-derived extracellular vesicles (BEVs).

Methods: BEVs were isolated by Sepharose-based size exclusion chromatography and defined as CD19+ and HLA-II+ extracellular vesicles. We analyzed stored serum samples from positive crossmatch LDKT recipients before and after desensitization at first post-transplant biopsy and at 12-month protocol biopsy (n = 11). Control groups were formed by hypersensitized patients who were not submitted to desensitization (n = 10) and by low-risk recipients (n = 9). A prospective validation cohort of 11 patients also included the analysis of B cells subpopulations in recipients' blood and lymph nodes recovered upon graft implantation, along with BEVs analysis before and after desensitization.

Results: We found out that CD19+ and HLA-II+BEVs dropped significantly after desensitization and relapse in patients who later developed ABMR was evident. We validated these findings in a proof-of-concept prospective cohort of 6 patients who received the same desensitization protocol and also in a control group of 5 LDKT recipients. In these patients, B cell subpopulations were also studied in recipients' blood and lymph nodes that were recovered before the graft implantation. We confirmed the significant drop in BEVs after desensitization and that this paralleled the reduction in CD19+cells in lymph nodes, while in peripheral blood B cells, this change was almost undetectable.

Conclusions: BEVs reflected B cell residual activity after desensitization and this could be a valid surrogate of humoral alloreactivity in this setting.

Influence of Persistent Inflammation in Follow-Up Biopsies After Antibody-Mediated Rejection in Kidney Transplantation

Background: Despite recent advances in immunosuppression treatment, antibody-mediated rejection (ABMR) remains the leading cause of kidney graft loss. Information about prognostic markers and the efficacy of treatment is scarce.

Methods: Retrospective study with kidney recipients diagnosed an active ABMR from January 1, 2004 to December 31, 2019 to explore the influence of persistent inflammation in follow-up biopsies on graft survival after ABMR treatment.

Results: About 116 patients were included. Active ABMR were treated with a combination of plasma exchange (PE), intravenous immunoglobulin (IVIg), rituximab, and steroids. At 6 months of treatment, 63 (54.3%) patients presented a stabilization or improvement in kidney-graft function. The effectiveness varied depending on the timepoint of the presentation between transplantation and rejection, which is lower for those with late ABMR (63 vs. 21% for early vs. late ABMR, respectively). Ninety patients (77%) underwent a control biopsy after ABMR treatment, from which 46 (51%) responded to the treatment. Microvascular inflammation (MVI) persisted in 64 (71%) biopsies, whereas tubulitis persisted in 17 (19%) biopsies. Death-censored graft survival at 1 year was significantly lower in patients with persistent MVI (86% vs. 95% without persistent MVI, P = 0.002), or with persistent tubulitis (44% vs. 66% without tubulitis, P = 0.02). In the Cox Regression analysis, the persistence of MVI [hazard ratio (HR), 4.50 (95%CI, 1.35–14.96), P = 0.01] and tubulitis [HR 2.88 95%CI (1.24–6.69), P = 0.01) in follow-up biopsies significantly increased the risk of graft failure.

Conclusion: Persistent inflammation in follow-up biopsies after ABMR treatment was associated with an increased risk of graft loss, even without meeting Banff rejection criteria.

Study Registration: Agencia Española de Medicamentos y Productos Sanitarios (AEMPS): 14566/RG 24161. Study code: UTRINM-2017-01.

A Novel Virtual Coaching System Based on Personalized Clinical Pathways for Rehabilitation of Older Adults-Requirements and Implementation Plan of the vCare Project

Home-based rehabilitation after an acute episode or following an exacerbation of a chronic disease is often problematic with a clear lack of continuity of care between hospital and home care. Secondary prevention is an essential element of long-term rehabilitation where strategies oriented toward risk reduction, treatment adherence, and optimization of quality of life need to be applied. Frail and sometimes isolated, the patient fails to adhere to the proposed post-discharge clinical pathway due to lack of appropriate clinical, emotional, and informational support. Providing a suitable rehabilitation after an acute episode or a chronic disease is a major issue, as it helps people to live independently and enhance their quality of life. However, as the rehabilitation period usually lasts some months, the continuity of care is often interrupted in the transition from hospital to home. Virtual coaches could help these patients to engage in a personalized rehabilitation program that complies with age-related conditions. These coaches could be a key technology for empowering patients toward increasing their adherence to the care plan and to improve their secondary prevention measures. In this paper, we are presenting a novel virtual coaching system that will address these challenges by combining recent technological advances with clinical pathways, based on joint research and validation activities from researchers from the medical and information and communication technology (ICT) domains.

Cellular and humoral response after MRNA-1273 SARS-CoV-2 vaccine in kidney transplant recipients

According to preliminary data, seroconversion after mRNA SARS-CoV-2 vaccination might be unsatisfactory in Kidney Transplant Recipients (KTRs). However, it is unknown if seronegative patients develop at least a cellular response that could offer a certain grade of protection against SARS-CoV-2. To answer this question, we prospectively studied 148 recipients of either kidney (133) or kidney-pancreas (15) grafts with assessment of IgM/IgG spike (S) antibodies and ELISpot against the nucleocapside (N) and the S protein at baseline and 2 weeks after receiving the second dose of the mRNA-1273 (Moderna) vaccine. At baseline, 31 patients (20.9%) had either IgM/IgG or ELISpot positivity and were considered to be SARS-CoV-2-pre-immunized, while 117 (79.1%) patients had no signs of either cellular or humoral response and were considered SARS-CoV-2-naïve. After vaccination, naïve patients who developed either humoral or cellular response were finally 65.0%, of which 29.9% developed either IgG or IgM and 35.0% S-ELISpot positivity. Factors associated with vaccine unresponsiveness were diabetes and treatment with antithymocytes globulins during the last year. Side effects were consistent with that of the pivotal trial and no DSAs developed after vaccination. In conclusion, mRNA-1273 SARS-CoV-2 vaccine elicits either cellular or humoral response in almost two thirds of KTRs.

Advantages of plasmatic CXCL-10 as a prognostic and diagnostic biomarker for the risk of rejection and subclinical rejection in kidney transplantation

This study evaluate the potential of plasmatic CXCL-10 (pCXCL-10) as a pre&post transplantation prognostic and diagnostic biomarker of T-cell-mediated rejection (TCMR), antibody-mediated rejection (ABMR) and subclinical rejection (SCR) risk in adult kidney recipients considering BKV and CMV infections as possible clinical confounder factors. Twenty-eight of 100 patients included experienced rejection (TCMR:14; ABMR:14); 8 SCR; 13 and 16 were diagnosed with BKV and CMV infection, respectively. Pre-transplantation pCXCL-10 was significantly increased in TCMR and ABMR and post-transplantation in TCMR, ABMR and SCR compared with nonrejectors. All CMV⁺ patients showed pCXCL-10 levels above the cutoff values established for rejection whereas the 80% of BKV⁺ patients showed pCXCL-10 concentration < 100 pg/mL. pCXCL-10 could improve pre-transplantation patient stratification and immunosuppressive treatment selection according to rejection risk; and after kidney transplantation could be a potential early prognostic biomarker for rejection. Clinical confounding factor in BKV⁺ and particularly in CMV⁺ patients must be discarded.

Assessing the pressure resistance of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica to high pressure processing (HPP) in citric acid model solutions for process validation

Despite the commercial success of high pressure processing (HPP) in the juice industry, some regulatory agencies still require process validation. However, there is a lack of consensus on various aspects regarding validation protocols, including the selection of representative strains to be used in challenge tests. This study characterized the variable response of Escherichia coli O157:H7 (34 strains), Listeria monocytogenes (44 strains) and Salmonella enterica (45 strains) to HPP, and identified potential candidates to use in process validation. Stationary phase cells were submitted to 500 MPa for 1 min at 10 °C in model solutions consisting of tryptic soy broth + 0.6% yeast extract (TSBYE) adjusted to pH 4.5 and 6.0 with citric acid. At pH 6.0, pressure resistance widely varied between species and within strains of the same species. E. coli O157:H7 and L. monocytogenes were the most pressure resistant and showed high variability at strain level, as the total count range given by minimum and maximum counts spread between 2.0 and 6.5 log₁₀ CFU/ml. S. enterica was the least resistant pathogen with more than 82% of the isolates displaying non-detectable counts after HPP. Recovery through storage at 12 °C was also variable for all pathogens, but eventually most strains recovered with median counts on day 14 between 8.3 and 8.9 log₁₀ CFU/ml. For pH 4.5 solutions, 26 E. coli O157:H7 strains displayed survivors after HPP but did not adapt, registering non-detectable counts in the next sampling dates. None of the L. monocytogenes and S. enterica strains survived HPP or incubation at pH 4.5 (<2.0 log₁₀ CFU/ml), suggesting that citric acid at 4.16 g/l is a safe barrier for pathogen control under moderate HPP conditions. Principal component and cluster analyses served to propose strain cocktails for each species based on their pressure resistant and adaptation phenotypes. Additionally, S. enterica was identified as less pressure resistant and less prone to recover following HPP than E. coli O157:H7 and L. monocytogenes, so its relevance in process validation for juices should be questioned. Future work will validate the proposed strain cocktails on real food systems.

Isolation of Extracellular Vesicles Derived from Mesenchymal Stromal Cells by Ultracentrifugation

Extracellular vesicles (EVs) are a heterogeneous group of membranous vesicles that differ on their biogenesis and release pathways, such as exosomes, microvesicles and apoptotic bodies. They are involved in cell-to-cell communication delivering signal molecules (proteins, nucleic acids, lipids, etc.) that can regulate different physiological processes, as well as the development and progression of several diseases. There are different methods and commercial kits to isolate EVs and depending on the methodology one could obtain EVs with different degrees of efficiency, purity and it can be more or less time-consuming. Then, the choice has to be according to the different advantages and disadvantages, and their use for downstream applications. Here, we describe the EVs isolation method from mesenchymal stromal cells by ultracentrifugation. This EVs isolation can be performed using common media and buffers, and only with the requirement of an analytical ultracentrifuge. Moreover, this method can be used to obtain large quantity of EVs with a good reproducibility for developing in vitro and in vivo experiments and studying their biological actions.

The impact of functional delayed graft function in the modern era of kidney transplantation - A retrospective study

The dialysis-based definition of Delayed Graft Function (dDGF) is not necessarily objective as it depends on the individual physician's decision. The functional definition of DGF (fDGF, the failure of serum creatinine to decrease by at least 10% daily on 3 consecutive days during the first week post-transplant), may be more sensitive to reflect recovery after the ischemia-reperfusion injury. We retrospectively analyzed both definitions in 253 deceased donor kidney transplant recipients for predicting death-censored graft failure as primary outcome, using eGFR < 25 ml/min/1.73 m² as a surrogate end-point for graft failure. Secondary outcome was a composite outcome that included graft failure as above and also patient's death. Median follow-up was 3.22 [2.38-4.21] years. Seventy-nine patients developed dDGF (31.2%) and 127 developed fDGF (50.2%). Sixty-three patients fulfilled criteria for both definitions (24.9%). At multivariable analysis, the two definitions were significantly associated with the primary [HR (95%CI) 2.07 (1.09-3.94), P = 0.026 for fDGF and HR (95%CI) 2.41 (1.33-4.37), P = 0.004 for dDGF] and the secondary composite outcome [HR (95%CI) 1.58 (1.01-2.51), P = 0.047 for fDGF and HR (95%CI) 1.67 (1.05-2.66), P = 0.028 for dDGF]. Patients who met criteria for both definitions had the worst prognosis, with a three-year estimates (95%CI) of survival from the primary and secondary outcomes of 2.31 (2.02-2.59) and 2.20 (1.91-2.49) years for fDGF+/dDGF+, in comparison with the other groups (P < 0.01 for trend). fDGF provides supplementary information about graft outcomes on top of the dDGF definition in a modern series of kidney transplantation.

Apixaban Downregulates Endothelial Inflammatory and Prothrombotic Phenotype in an In Vitro Model of Endothelial Dysfunction in Uremia

PURPOSE

Chronic kidney disease (CKD) associates with inflammatory and prothrombotic phenotypes, resulting in higher cardiovascular risk. Factor Xa displays functions beyond coagulation, exhibiting proinflammatory effects. The aim of the present study was to investigate whether a direct FXa inhibitor protects from the endothelial dysfunction (ED) caused by uremia.

METHODS

Macro (HUVEC) and microvascular (HMEC) endothelial cells (ECs) were exposed to serum from uremic patients or healthy donors, in absence and presence of apixaban (60 ng/ml). We evaluated changes in surface VCAM-1 and ICAM-1, intracellular eNOS, reactive oxygen species (ROS), and von Willebrand Factor (VWF) production by immunofluorescence, reactivity of the extracellular matrix (ECM) towards platelets, and intracellular signaling.

RESULTS

ECs exposed to uremic serum triggered dysregulation of all the parameters. Presence of apixaban resulted in decreased expression of VCAM-1 (178 ± 14 to 89 ± 2% on HMEC and 324 ± 71 to 142 ± 25% on HUVEC) and ICAM-1 (388 ± 60 to 111 ± 10% on HMEC and 148 ± 9% to 90 ± 7% on HUVEC); increased eNOS (72 ± 8% to 95 ± 10% on HMEC); normalization of ROS levels (173 ± 21 to 114 ± 13% on HMEC and 165 ± 14 to 127 ± 7% on HUVEC); lower production of VWF (168 ± 14 to 92 ± 4% on HMEC and 151 ± 22 to 99 ± 11% on HUVEC); and decreased platelet adhesion onto ECM (134 ± 22 to 93 ± 23% on HMEC and 161 ± 14 to 117 ± 7% on HUVEC). Apixaban inhibited p38MAPK and p42/44 activation in HUVEC (139 ± 15 to 48 ± 15% and 411 ± 66 to 177 ± 57%, respectively) (p < 0.05 vs control for all parameters).

CONCLUSION

Anti-FXa strategies, such as apixaban, prevented ED caused by the uremic milieu, exhibiting anti-inflammatory and antioxidant properties and modulating the reactivity of the ECM.

Reconstruction of phthalate exposure and DINCH metabolites from biomonitoring data from the EXHES cohort of Tarragona, Spain: A case study on estimated vs reconstructed DEHP using the PBPK model

Phthalates are known endocrine disruptors (EDs) and are associated with potential diseases, such as obesity and diabetes. In 2002, the plasticizer 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) was introduced as an alternative to phthalates in the European market. The objective of this study was to evaluate the total exposure to phthalate and DINCH metabolites from EXHES Tarragona, Spain cohort of pregnant women. On the one hand, the analytical determination of phthalate and DINCH metabolites in urine was carried out. On the other hand, the reconstructed exposure was calculated for phthalates and DINCH using their metabolites concentration measured in the urine. Thirteen different phthalate metabolites and two metabolites of DINCH were measured and detected in almost all pregnant women's urine samples (n = 60). There were significant correlations between metabolites of the same parent compounds, and also between DEHP and MBzP metabolites, DiNP and BBZP metabolites, and DEHP and DiNP metabolites respectively. The exposure of pregnant women to phthalate and DINCH parent compounds were also back calculated using the levels of each metabolite found in pregnant women urine (reconstructed exposure). Besides, to demonstrate the utility of this approach, the physiologically based pharmacokinetic (PBPK) model was used to predict the cumulative amount of MEHP (a principal metabolite of DEHP in urine). To proceed with that, DEHP reconstructed exposure and estimated exposure from the same cohort (previously studied by the same authors) were simulated using the PBPK model. Results showed that the reconstructed-PBPK simulation was closer to the 24 h biomonitoring data than the estimated PBPK-simulation., This clearly shows that the combination of reconstructed exposure with the PBPK model is a good tool to predict chemicals exposure. However, some discrepancies between simulated and biomonitored values were found. This can be associated with other sources that contribute to the total exposure and emphasises the need to consider multi-routes exposure for the widely distributed chemicals like phthalates and DINCH.

Evaluation of factors influencing the growth of non-toxigenic Clostridium botulinum type E and Clostridium sp. in high-pressure processed and conditioned tender coconut water from Thailand

Bacterial spores survive high pressure processing (HPP). Group II Clostridium botulinum is an obligate anaerobe spore-forming pathogen that can produce the botulinum neurotoxin under refrigeration. This study assessed nontoxigenic type E C. botulinum and Group II Clostridium sp. growth in raw and HPP (550 MPa, 3 min, 10 °C) Thai coconut water (CCW; pH 5.2). No spore germination or growth occurred in HPP CCW inoculated with 10⁵ CFU/ml after 61 days regardless of oxygen concentration (<0.5 - 11 mg/l) or storage temperature (4 and 20 °C). Spore concentration decreased by 3.0 ± 0.1 log CFU/ml in a worst-case scenario consisting of non-HPP filter-sterilized CCW (pH 7.0) under anoxic incubation at 30 °C during 61 days, suggesting spore germination followed by cellular death. Supplementing filter-sterilized CCW (pH 7.0) with selected germinants and free amino acids did not support spore development, but the addition of nutrient-rich laboratory media (TPGY broth) at low concentrations (6.25%) promoted growth, suggesting that a lack of nutrients prevents C. botulinum development in CCW. Further risk assessment will require evaluating other CCW varieties and toxin production.

P1761SIDE EFFECTS OF MTOR INHIBITORS DEPEND ON THE BASELINE METABOLIC STATUS OF KIDNEY TRANSPLANT RECIPIENTS

Background and Aims

Biologically, the cellular activity of the mTOR complexes depends on the balance between the catabolic and the anabolic inputs. Hence, we hypothesized that the metabolic side effects of mTOR inhibitors (mTORi) in kidney transplantation depend on the baseline metabolic status of the patient.

Method

The analysis included all the patients that have been transplanted in our Center between June 2013 to December 2016, completed one year of follow-up and did not change medication during the first year after kidney transplantation (per-protocol population, n=298). Outcomes chosen include de novo diabetes, 1-year difference from baseline in glycated hemoglobin (HbA1c), triglycerides and total cholesterol. Kidney transplant recipients were treated either with an mTORi (either Sirolimus or Everolimus, n=134) or Mycophenolic Acid (MPA, n=164). Both drugs were always accompanied by tacrolimus and steroids. Patients were stratified according to the treatment received (mTORi versus MPA) and the baseline metabolic status (diabetes mellitus type 2 and obesity). Differences among groups were analyzed with exact Fisher test and ANOVA test with LSD post-hoc analysis.

Results

We observed a strong difference for 1-year change in HbA1c depending on the baseline metabolic status of the patients (P&lt;0.001 between groups, Figure 1a). The worst results were observed for patients with baseline diabetes. Among these, obese patients treated with mTORi had the higher increase in HbA1c (3.04 ± 1.18% from baseline, P&lt;0.01 with all groups at post-hoc analysis). De-novo diabetes was more frequent in patients taking mTORi (23.4 vs. 13.1%), albeit not significantly (P=0.100) and without differences taking into account obesity as a covariate. Triglycerides increased substantially in patients without baseline diabetes and treated with mTORi (P&lt;0.05). Surprisingly, in diabetic patients no differences were observed in triglycerides between mTORi and MPA groups (Figure 1b). There were no differences in the increase in total cholesterol among groups (P=0.155) (Figure 1c).

Conclusion

We observed that the 1-year increase in HbA1c and triglycerides attributable to mTORi after kidney transplantation depends on the baseline metabolic status of the patients. We propose that the metabolic side effects of mTORi depend on the balance between anabolic and catabolic inputs of every kidney transplant recipient.

Nephroprotective Potential of Mesenchymal Stromal Cells and Their Extracellular Vesicles in a Murine Model of Chronic Cyclosporine Nephrotoxicity

Background

Cell therapies and derived products have a high potential in aiding tissue and organ repairing and have therefore been considered as potential therapies for treating renal diseases. However, few studies have evaluated the impact of these therapies according to the stage of chronic kidney disease. The aim of this study was to evaluate the renoprotective effect of murine bone marrow mesenchymal stromal cells (BM-MSCs), their extracellular vesicles (EVs) and EVs-depleted conditioned medium (dCM) in an aggressive mouse model of chronic cyclosporine (CsA) nephrotoxicity in a preventive and curative manner.

Methods

After 4 weeks of CsA-treatment (75 mg/kg daily) mice developed severe nephrotoxicity associated with a poor survival rate of 25%, and characterized by tubular vacuolization, casts, and cysts in renal histology. BM-MSC, EVs and dCM groups were administered as prophylaxis or as treatment of CsA nephrotoxicity. The effect of the cell therapies was analyzed by assessing renal function, histological damage, apoptotic cell death, and gene expression of fibrotic mediators.

Results

Combined administration of CsA and BM-MSCs ameliorated the mice survival rates (6-15%), but significantly renal function, and histological parameters, translating into a reduction of apoptosis and fibrotic markers. On the other hand, EVs and dCM administration were only associated with a partial recovery of renal function or histological damage. Better results were obtained when used as treatment rather than as prophylactic regimen i.e., cell therapy was more effective once the damage was established.

Conclusion

In this study, we showed that BM-MSCs induce an improvement in renal outcomes in an animal model of CsA nephrotoxicity, particularly if the inflammatory microenvironment is already established. EVs and dCM treatment induce a partial recovery, indicating that further experiments are required to adjust timing and dose for better long-term outcomes.

Kidney Graft Outcomes in High Immunological Risk Simultaneous Liver-Kidney Transplants

Recipients of simultaneous liver-kidney transplantations (SLKTs) have a lower risk of rejection compared with recipients of kidney transplants alone. However, there is disagreement about the impact of pretransplant anti-human leukocyte antigen sensitization on patient and kidney graft survival in the long term. The aim of the study was to evaluate the impact of the recipient immunological risk and comorbidities in renal graft outcomes on SLKT. We reviewed the SLKTs performed in our center from May 1993 until September 2017. Patient and graft survival were analyzed according to the immunological risk, comorbidities, liver and kidney rejection episodes, immunosuppression, and infections. A total of 20 recipients of SLKT were considered in the high immunological risk (HIR) group, and 68 recipients were included in the low immunological risk (LIR) control group. The prevalence of hepatitis C virus infection, second renal transplant, and time on dialysis prior to transplantation were significantly higher in the HIR group. The incidence of acute kidney rejection was higher in the HIR group (P<0.01). However, death-censored kidney graft survival as well as the estimated glomerular filtration rate at follow-up were not different between the 2 groups. Comorbidities, but not the immunological risk, impact negatively on patient survival. Despite the higher incidence of rejection in the HIR SLKT group, longterm renal function and graft survival were similar to the LIR group.

Impact of Mesenchymal Stromal Cells and Their Extracellular Vesicles in a Rat Model of Kidney Rejection

Background

Mesenchymal stromal cells (MSCs) from different sources possess great therapeutic potential due to their immunomodulatory properties associated with allograft tolerance. However, a crucial role in this activity resides in extracellular vesicles (EVs) and signaling molecules secreted by cells. This study aimed to evaluate the immunomodulatory properties of donor and recipient MSCs isolated from adipose tissue (AD) or bone marrow (BM) and their EVs on kidney outcome in a rat kidney transplant model.

Methods

The heterotopic-kidney-transplant Fisher-to-Lewis rat model (F-L) was performed to study mixed cellular and humoral rejection. After kidney transplantation, Lewis recipients were assigned to 10 groups; two control groups; four groups received autologous MSCs (either AD- or BM- MSC) or EVs (derived from both cell types); and four groups received donor-derived MSCs or EVs. AD and BM-EVs were purified by ultracentrifugation. Autologous cell therapies were administered three times intravenously; immediately after kidney transplantation, 4 and 8 weeks, whereas donor-derived cell therapies were administered once intravenously immediately after transplantation. Survival and renal function were monitored. Twelve weeks after kidney transplantation grafts were harvested, infiltrating lymphocytes were analyzed by flow cytometry and histological lesions were characterized.

Results

Autologous AD- and BM-MSCs, but not their EVs, prolonged graft and recipient survival in a rat model of kidney rejection. Autologous AD- and BM-MSCs significantly improved renal function during the first 4 weeks after transplantation. The amelioration of graft function could be associated with an improvement in tubular damage, as well as in T, and NK cell infiltration. On the other side, the application of donor-derived AD-MSC was harmful, and all rats died before the end of the protocol. AD-EVs did not accelerate the rejection. Contrary to autologous MSCs results, the single dose of donor-derived BM-MSCs is not enough to ameliorate kidney graft damage.

Conclusion

EVs treatments did not exert any benefit in our experimental settings. In the autologous setting, BM-MSCs prompted as a potentially promising therapy to improve kidney graft outcomes in rats with chronic mixed rejection. In the donor-derived setting, AD-MSC accelerated progression to end-stage kidney disease. Further experiments are required to adjust timing and dose for better long-term outcomes.

Combination of calcineurin and mTOR inhibitors in kidney transplantation: a propensity score analysis based on current clinical practice

INTRODUCTION

The TRANSFORM study demonstrated that an immunosuppression based on a combination of calcineurin inhibitors and de-novo mTOR inhibitors (mTORi) is safe and effective in kidney transplant recipients. However, data that validate this approach in clinical practice are currently missing.

MATERIALS AND METHODS

Analysis of 401 kidney transplant recipients transplanted from June 2013 to December 2016. All patients received tacrolimus with prednisone in combination with either mycophenolate (n = 186) or mTORi (either everolimus or sirolimus, n = 215). A propensity score to receive mTORi was calculated based on the inverse probability of treatment weighting (IPTW) from the following parameters: age and sex of donor and recipient, BMI, previous transplants, diabetes, cPRA, dialysis before transplantation, dialysis vintage, type of donor, ABO-incompatibility, HLA-mismatches, induction and ischemia time. Median follow-up was 2.6 [1.9; 3.7] years.

RESULTS

Cox-regression analysis suggests good results for mTORi versus MPA in terms of 1-year biopsy-proven acute rejection (BPAR, P = 0.063), 1-year graft loss (P = 0.025) and patient survival (P < 0.001). Results observed for BPAR and graft failure were largely attributed to those patients that would have been excluded by the TRANSFORM because of some exclusion criteria (52.9% of the population, P = 0.003 for 1-year BPAR and P = 0.040 for graft loss). In patients who met selection criteria for TRANSFORM, no effect of treatment for BPAR or graft failure was observed, while the beneficial effect on overall survival persisted.

CONCLUSIONS

In a real-life setting, a protocol based on de-novo mTORi with tacrolimus and prednisone could be employed as a standard immunosuppressive regimen and was associated with good outcomes.

A mathematical modeling approach to the quantification of lactic acid bacteria in vacuum-packaged samples of cooked meat: Combining the TaqMan-based quantitative PCR method with the plate-count method

The TaqMan-based quantitative Polymerase Chain Reaction (qPCR) method and the Plate Count (PC) method are both used in combination with primary and secondary mathematical modeling, to describe the growth curves of Leuconostoc mesenteroides and Weissella viridescens in vacuum-packaged meat products during storage under different isothermal conditions. Vacuum-Packaged Morcilla (VPM), a typical cooked blood sausage, is used as a representative meat product, with the aim of improving shelf-life prediction methods for those sorts of meat products. The standard curves constructed by qPCR showed good linearity between the cycle threshold (C_T) and log₁₀ CFU/g, demonstrating the high precision and the reproducible results of the qPCR method. The curves were used for the quantification of L. mesenteroides and W. viridescens in artificially inoculated VPM samples under isothermal storage (5, 8, 13 and 18 °C). Primally, both the qPCR and the PC methods were compared, and a linear regression analysis demonstrated a statistically significant linear correlation between the methods. Secondly, the Baranyi and Roberts model was fitted to the growth curve data to estimate the kinetic parameters of L. mesenteroides and W. viridescens under isothermal conditions, and secondary models were used to establish the dependence of the maximum specific growth rate on the temperature. The results proved that primary and secondary models were adequate for describing the growth curves of both methods in relation to both bacteria. In conclusion, the results of all the experiments proved that the qPCR method in combination with the PC method can be used to construct microbial growth kinetics and that primary and secondary mathematical modeling can be successfully applied to describe the growth of L. mesenteroides and W. viridescens in vacuum-packaged morcilla and, by extension, other cooked meat products with similar characteristics.

Inhibition of the mTOR pathway: A new mechanism of β cell toxicity induced by tacrolimus

The mechanisms of tacrolimus-induced β cell toxicity are unknown. Tacrolimus (TAC) and rapamycin (Rapa) both bind to FK506-binding protein 12 (FKBP12). Also, both molecular structures are similar. Because of this similarity, we hypothesized that TAC can also inhibit the mTOR signalling, constituting a possible mechanism of β cell toxicity. Thus, we studied the effect of TAC and Rapa over the mTOR pathway, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), and insulin secretion and content in INS-1 β cells treated with or without glucose and palmitate and in islets from lean or obese rats. TAC and Rapa inhibited the mTOR pathway as reflected by lower levels of phospho-mTOR, phospo-p70S6K, and phospo-S6. The effect of Rapa was larger than TAC. Both drugs reduced the levels of MafA, insulin secretion, and content although these effects were larger with TAC. The changes on MafA and insulin metabolism were observed in cells on glucose and palmitate, in obese animals, and were absent in cells on maintenance medium or in lean animals. In silico docking and immunoprecipitation experiments confirmed that TAC can form a stable noncovalent interaction with FKBP12-mTOR. Thus, the mTOR inhibition may be a mechanism contributing to the diabetogenic effect of TAC.

Characterization of Virulence and Persistence Abilities of Listeria monocytogenes Strains Isolated from Food Processing Premises

We report the characterization of 15 Listeria monocytogenes strains isolated from various food processing plants by multivirulence locus sequence typing to determine virulence types (VTs) and epidemic clones. Molecular mechanisms involved in adaptation to food processing environments and related to virulence were also studied. Phenotypic behaviors associated with various antimicrobials, biofilm formations, and invasiveness were assessed. There were 11 VTs among the 15 L. monocytogenes strains. Strains belonging to six VTs were stress survival islet 1 (SSI-1) and one strain of VT94 was SSI-2. Tn6188 was found in VT6 and VT94 strains, and bcrABC cassette genes were identified in VT21, VT60, and VT63 strains. Only one strain, in VT20, showed llxS, whereas a full-size inlA was detected in strains belonging to VT8, VT20, VT21, and VT63. VT10, VT20, VT21, VT60, and VT63 strains were the most tolerant to studied disinfectants. A VT6 strain showed the strongest biofilm formation ability in polyvinyl chloride, and strains belonging to VT10, VT11, VT20, and VT94 had moderate abilities. Antimicrobial sensitivity tests showed that all the L. monocytogenes strains were multidrug resistant. F tests revealed that only strains of VT10, VT60, and VT94 were significantly noninvasive (P < 0.05) in Caco-2 cells. Our findings illustrate how L. monocytogenes isolates exploit diverse mechanisms to adapt to adverse conditions. Consequently, detailed characterization of L. monocytogenes isolates is required for comprehensive elimination of this pathogenic bacterium in food processing environments.

Distribution and Persistence of Listeria monocytogenes in a Heavily Contaminated Poultry Processing Facility

We studied the colonization and distribution of Listeria monocytogenes in a heavily contaminated poultry processing plant over a 1-year period. A total of 180 nonfood contact surfaces, 70 food contact surfaces, 29 personnel, and 40 food samples were analyzed. L. monocytogenes isolates were subtyped by PCR serotyping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. L. monocytogenes was detected in samples collected at every visit to the plant, and 43.8% (visit 4) to 65.6% (visit 7) of samples were positive, for an overall prevalence of 55.2%. The deboning area had the highest prevalence of positive samples (83.3%), and the processing area had the highest diversity of PFGE types. Ninety percent of the final products were positive for L. monocytogenes. Most of the isolates belonged to well-known persistent L. monocytogenes sequence types (ST9 and ST121). This study illustrates a well-established L. monocytogenes contamination problem in a poultry processing plant associated with a generalized failure of the food safety system as a whole. These findings reflect the potential for L. monocytogenes contamination when the food safety and quality management system is unsatisfactory, as described in the present study. It is essential to revise food safety and quality management systems to eliminate L. monocytogenes from food processing facilities, to control the entrance of sporadic sequence types, and to prevent L. monocytogenes spread within such facilities, especially in those premises with higher L. monocytogenes prevalence in the environment and final food products.

Effect of immunosuppression in miRNAs from extracellular vesicles of colorectal cancer and their influence on the pre-metastatic niche

Colorectal cancer (CRC) occurs with more aggressiveness in kidney transplant recipients compared to the general population. Immunosuppressive therapy plays a crucial role in the development of post-transplant malignancy. Concretely, cyclosporine A (CsA) has intrinsic pro-oncologic properties, while several studies report a regression of cancer after the introduction of rapamycin (RAPA). However, their effect on the extracellular vesicle (EV) content from CRC cell lines and their relevance in the pre-metastatic niche have not yet been studied. Here, we investigated the effect of RAPA and CsA in EV-miRNAs from metastatic and non-metastatic CRC cell lines and the role of relevant miRNAs transferred into a pre-metastatic niche model. EV-miRNA profiles showed a significant upregulation of miR-6127, miR-6746-5p, and miR-6787-5p under RAPA treatment compared to CsA and untreated conditions in metastatic cell lines that were not observed in non-metastatic cells. From gene expression analysis of transfected lung fibroblasts, we identified 22 shared downregulated genes mostly represented by the histone family involved in chromatin organization, DNA packaging, and cell cycle. These results suggest that EV-miR-6127, miR-6746-5p and miR-6787-5p could be a potential epigenetic mechanism induced by RAPA therapy in the regulation of the pre-metastatic niche of post-transplant colorectal cancer.