Reconstitution of immunodeficient SCID/beige mice with human cells: applications in preclinical studies.

International audienceExperimental studies of the in vivo behaviour of human cells and tissues have become possible with the development of immunodeficient mice strains. Such mice accept readily allogeneic or xenogeneic grafts, including grafts of human cells or tissues, without rejection. In this review we describe different immunodeficient mouse strains that have been used for reconstitution by human immune cells. We subsequently go through the experience that we and others have had with reconstitution, and mention the adverse effects, in particular xenogeneic graft versus host reactions. The use of haematopoietic stem cells avoids such reactions but the immunological reconstitution may take several months. We then report the use of immunodeficient mice for the study of chronic vascular rejection of human mesenteric arteries due to cellular or humoral alloreaction. We have shown that SCID/beige mice grafted with a human artery at the place of the aorta developed a thickening of the intima of the human artery after 5-6 weeks, when they were reconstituted with spleen cells from another human donor. The thickening is mainly due to a proliferation of smooth muscle cells. The same type of lesion developed if they received injection of antibodies towards HLA class I antigens. The arteries of the mouse did not develop any lesion. The arterial lesions closely resembled those seen after clinical organ transplantation. Mice that received spleen cells from the same human donor developed little or no lesions. An important aspect of this experimental transplantation model is the possibility to test drugs that may be used in clinical transplantation. In recent experiments we have shown that novel immunosuppressive drugs can inhibit the hyperproliferation of smooth muscle cells in vitro. Preclinical testing in reconstituted SCID/beige mice grafted with human arteries will permit the evaluation of the potential use of these drugs to prevent chronic vascular rejection. The model also allows pharmacodynamic studies that give information on the biological impact of different drugs that may be used in experimental or clinical transplantation

Primary Thromboprophylaxis in Ambulatory Pancreatic Cancer Patients Receiving Chemotherapy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

International audiencePatients with pancreatic cancer (PC) carry the highest risk of venous thromboembolism (VTE) amongst all cancer patients. Appropriate use of primary thromboprophylaxis might significantly and safely reduce its burden. We performed a systematic review of published studies and meeting abstracts using MEDLINE and EMBASE through July 2020 to evaluate the efficacy and safety of primary thromboprophylaxis in ambulatory PC patients receiving chemotherapy. The Mantel-Haenszel random effect model was used to estimate the pooled event-based risk ratio (RR) and the pooled absolute risk difference (RD) with a 95% confidence interval (CI). Five randomized controlled studies with 1003 PC patients were included in this meta-analysis. Compared to placebo, thromboprophylaxis significantly decreased the risk of VTE (pooled RR 0.31, 95% CI 0.19-0.51, p < 0.00001, I2 = 8%; absolute RD -0.08, 95% CI -0.12--0.05, p < 0.00001, I2 = 0%), with an estimated number needed to treat of 11.9 patients to prevent one VTE event. Similar reductions of VTE were observed in studies with parenteral (RR 0.30, 95% CI 0.17-0.53) versus oral anticoagulants (RR 0.37, 95% CI 0.14-0.99) and in studies using prophylactic doses of anticoagulants (RR 0.34, 95% CI 0.17-0.70) versus supra-prophylactic doses of anticoagulants (RR 0.27, 95% CI 0.08-0.90). The pooled RR for major bleeding was 1.08 (95% CI 0.47-2.52, p = 0.85, I2 = 0%) and the absolute RD was 0.00 (95% CI -0.02-0.03, p = 0.85, I2 = 0%). Evidence supports a net clinical benefit of thromboprophylaxis in ambulatory PC patients receiving chemotherapy. Adequately powered randomized phase III studies assessing the most effective anticoagulant and the optimal dose, schedule and duration of thromboprophylaxis to be used are warranted

Incidence of Venous Thromboembolism in Patients With Newly Diagnosed Pancreatic Cancer and Factors Associated With Outcomes

International audienceBackground & aims: Pancreatic ductal adenocarcinoma (PDAC) is associated with the highest incidence of venous thromboembolism (VTE) of any cancer type. However, little is known about risk factors for VTE or its outcomes in patients with PDAC.Methods: We collected data from a prospective, observational study performed at multiple centers in France from May 2014 through November 2018 (the Base Clinico-Biologique de l'Adénocarcinome Pancréatique [BACAP] study) linked to a database of patients with a new diagnosis of PDAC of any stage. Data were collected from 731 patients at baseline and during clinical follow-up or in the event of symptoms. The primary endpoint was the onset of VTE during follow-up. The secondary endpoints were progression-free survival (PFS) and overall survival (OS) times.Results: During a median follow-up of 19.3 months, 152 patients (20.79%) developed a VTE. The median time from PDAC diagnosis to the onset of VTE was 4.49 months. Cumulative incidence values of VTE were 8.07% (95% confidence interval [CI], 6.31-10.29) at 3 months and 19.21% (95% CI, 16.27-22.62) at 12 months. In multivariate analysis, PDAC primary tumor location (isthmus vs head: hazard ratio [HR], 2.06; 95% CI, 1.09-3.91; P = .027) and stage (locally advanced vs resectable or borderline: HR, 1.66; 95% CI, 1.10-2.51, P = .016; metastatic vs resectable or borderline: HR, 2.50; 95% CI, 1.64-3.79; P < .001) were independent risk factors for the onset of VTE. Patients who developed VTE during follow-up had shorter times of PFS (HR, 1.74; 95% CI, 1.19-2.54; P = .004) and OS (HR, 2.02; 95% CI, 1.57-2.60; P < .001).Conclusion: In an analysis of data from the BACAP study, we found that frequent and early onsets of VTE after diagnoses of PDAC are associated with significant decreases in times of PFS and OS. Studies are needed to determine whether primary prophylaxis of VTE in patients with PDAC will improve morbidity and mortality related to VTE. (ClinicalTrials.gov, Number: clinicaltrials.gov as number NCT02818829)

Randomised clinical trial for the cost–utility evaluation of two strategies of perineal reconstruction after abdominoperineal resection in the context of anorectal carcinoma: biological mesh repair versus primary perineal wound closure, study protocol for the GRECCAR 9 Study

International audienceIntroduction: Abdominoperineal resections performed for anorectal tumours leave a large pelvic and perineal defect causing a high rate of morbidity of the perineal wound (40%-60%). Biological meshes offer possibilities for new standards of perineal wound reconstruction. Perineal fillings with biological mesh are expected to increase quality of life by reducing perineal morbidity.Methods and analysis: This is a multicentre, randomised and single-blinded study with a blinded endpoint evaluation, the experimental arm of which uses a biological mesh and the control arm of which is defined by the primary closure after abdominoperineal resection for cancer. Patients eligible for inclusion are patients with a proven history of rectal adenocarcinoma and anal canal epidermoid carcinoma for whom abdominoperineal resection was indicated after a multidisciplinary team discussion. All patients must have social security insurance or equivalent social protection. The main objective is to assess the incremental cost-utility ratio (ICUR) of two strategies of perineal closure after an abdominoperineal resection performed for anorectal cancer treatment: perineal filling with biological mesh versus primary perineal closure (70 patient in each arm). The secondary objectives focus on quality of life and morbidity data during a 1-year follow-up. Deterministic and probabilistic sensitivity analyses will be performed in order to estimate the uncertainty surrounding the ICUR. CIs will be constructed using the non-parametric bootstrap approach. A cost-effectiveness acceptability curve will be built so as to estimate the probability of efficiency of the biological meshes given a collective willingness-to-pay threshold.Ethics and dissemination: The study was approved by the Regional Ethical Review Board of 'Nord Ouest 1' (protocol reference number: 20.05.14.60714; national number: 2020-A01169-30).The results will be disseminated through conventional scientific channels.Trial registration number: ClinicalTrials.gov Registry (NCT02841293)

Pharmacodynamic monitoring of the conversion from mycophenolate mofetil to enteric-coated mycophenolate sodium in stable kidney-allograft recipients.

International audienceBACKGROUND: The formulations of mycophenolic acid, i.e., mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS), seem to have different pharmacokinetic profiles. The aim of this study was to compare the effects MMF and EC-MPS on T-cell proliferation, T-cell activation, T-cell function, and lymphocyte subsets. CLINICAL STUDY AND METHODS: Ten stable kidney-transplant patients on standard maintenance therapy of tacrolimus and MMF (1 g/d), with or without steroids, were converted from MMF to EC-MPS at equivalent dose (720 mg/d). Tacrolimus and steroid doses remained unchanged before, and at 1, 2, 3, and 6 months (M) after conversion. Intra T-lymphocyte cytokines IL-2 and TNF-alpha, lymphocyte-activation surface markers (CD25 and CD71), T-cell proliferation (PCNA+ PI(high)), total lymphocyte count, as well as lymphocytes subsets (CD2, CD3, CD4, CD8, CD19, NK cells) were measured by flow cytometry before conversion and at M1, M2, M3, and M6. RESULTS: We found no significant differences of MMF versus EC-MPS on lymphocyte function. T-cell proliferation and T-cell activation (CD25 and CD71 expression), but not cytokine expression (TNF-alpha and IL-2), showed a trend to increase after conversion from MMF to EC-MPS. Total lymphocyte, CD2, CD3, CD4, CD8, and NK cells counts were not significantly modified. CONCLUSION: This study revealed a trend to a lower immunosuppression with EC-MPS as compared to MMF in stable renal transplant patients

Inhibition of T-cell activation and proliferation by mycophenolic acid in patients awaiting liver transplantation: PK/PD relationships.

International audienceMycophenolic acid (MPA) plasma concentrations were reported to be associated with a decrease in T-cell proliferation, and in both IL-2 α-chain (CD25) and transferin receptor (CD71) expression. The aim of this study was to confirm, quantify and model these PK/PD relationships. Full profiles of MPA plasma concentrations, T-cell proliferation, intracytoplasmic IL-2 and TNF-α expression, and both CD71 and CD25 expression were collected over the 12h after dosing in 10 patients on the waiting list for liver transplantation. Data were analyzed using NONMEM(®). Both CD25 and CD71 expression and T cell proliferation clearly decreased (median of decrease from baseline 62%, 68% and 94%, respectively) with increasing MPA concentrations, in contrast to IL-2 and TNF-α expression. The CD25 and CD71 baseline expression (E(0)) and maximum effect (E(max)) were correlated with the E(0) and E(max) values of T-cell proliferation (r(2)=0.509 and r(2)=0.622, respectively). The CD25, CD71 expression and T-cell proliferation profiles were adequately fitted using a sigmoid inhibitory E(max) model. Low estimated values (≤2 mg/L) for 50% inhibitory MPA concentrations were obtained. This study confirmed a transient MPA concentration-dependent decrease in T-cells expressing CD25 and CD71 and a strong reduction of T-cell proliferation and showed that CD25 and CD71 expression was correlated with T-cell proliferation

FTY720 Inhibits Tumor Necrosis Factor-alpha-Induced Proliferation and Extracellular Signal-Regulated Kinase Phosphorylation of Human Smooth Muscle Cells.

International audienceWe investigated the effects of the sphingolipid FTY720 on tumor necrosis factor-alpha (TNF-alpha)-induced proliferation and signal transduction in human smooth muscle cells (SMC). We showed that clinically relevant concentrations of FTY720 inhibited TNF-alpha-induced SMC proliferation and extracellular signal-regulated kinase (ERK) phosphorylation. We concluded that FTY720 may be a useful drug to inhibit chronic vascular rejection

Perineal Wound Closure Following Abdominoperineal Resection and Pelvic Exenteration for Cancer: A Systematic Review and Meta-Analysis

International audienceBackground. Abdominoperineal resection (APR) and pelvic exenteration (PE) for thetreatment of cancer require extensive pelvic resection with a high rate of postoperative complications.The objective of this work was to systematically review and meta-analyze the effects of vertical rectusabdominis myocutaneous flap (VRAMf) and mesh closure on perineal morbidity following APR andPE (mainly for anal and rectal cancers). Methods. We searched PubMed, Cochrane, and EMBASE foreligible studies as of the year 2000. After data extraction, a meta-analysis was performed to compareperineal wound morbidity. The studies were distributed as follows: Group A comparing primaryclosure (PC) and VRAMf, Group B comparing PC and mesh closure, and Group C comparing PCand VRAMf in PE. Results. Our systematic review yielded 18 eligible studies involving 2180 patients(1206 primary closures, 647 flap closures, 327 mesh closures). The meta-analysis of Groups A and Bshowed PC to be associated with an increase in the rate of total (Group A: OR 0.55, 95% CI 0.43–0.71;p < 0.01/Group B: OR 0.54, CI 0.17–1.68; p = 0.18) and major perineal wound complications (Group A:OR 0.49, 95% CI 0.35–0.68; p < 0.001/Group B: OR 0.38, 95% CI 0.12–1.17; p < 0.01). PC was associatedwith a decrease in total (OR 2.46, 95% CI 1.39–4.35; p < 0.01) and major (OR 1.67, 95% CI 0.90–3.08;p = 0.1) perineal complications in Group C. Conclusions. Our results confirm the contribution of theVRAMf in reducing major complications in APR. Similarly, biological prostheses offer an interestingalternative in pelvic reconstruction. For PE, an adapted reconstruction must be proposed withspecialized expertise

Cytokines correlate with age in healthy volunteers, dialysis patients and kidney-transplant patients.

International audienceT-cell functions are currently used as biomarkers for the pharmacodynamic monitoring of immunosuppressive drugs or as disease biomarkers of inflammation/sepsis and organ rejection. In order to evaluate co-factors potentially influencing the expression of the immunological biomarkers, we explored T-cell proliferation, T-cell activation (CD25 and CD71 expressions) and intra-lymphocyte cytokine production (interleukin (IL)-2 and tumor necrosis factor (TNF)-alpha) in healthy volunteers, dialysis patients and stable kidney-transplant patients treated with standard immunosuppressive therapy, i.e. tacrolimus, mycophenolic acid with or without steroids. Age was positively correlated with TNF-alpha expression in all three patient populations, and with IL-2 expression in healthy volunteers and kidney-transplant patients. Further age was correlated with inhibition of lymphocyte proliferation in healthy volunteers and with the T-cell activation marker CD25 in kidney-transplant patients. In healthy volunteers lymphocyte proliferation was higher in woman as compared to men. Other biomarkers of T-cell function were independent of the gender. In the kidney-transplant patient group a significantly lower expression of all biomarkers of T-cell functions compared to healthy volunteers and dialysis patients. In dialysis patients we found significant increased IL-2 expression compared to healthy volunteers, while the other T-cell functions were not significantly different. Further time on dialysis had no effect on the level of biomarker expression. In conclusion we found decreased T-cell functions in kidney-transplant patients compared to healthy volunteers and dialysis patients, increased IL-2 expression in dialysis patients compared to healthy volunteers and in all three populations we found a correlation of age and intra-T-lymphocyte TNF-alpha expression

Polyoma BK virus-associated nephropathy in kidney-transplant patients: Effects of leflunomide on T-cell functions and disease outcome

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