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163 result(s) for "Adam, R. (René)"
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Aldehyde Dehydrogenase 2 (ALDH2) in Rat Fatty Liver Cold Ischemia Injury
Institut George Lopez-1 (IGL-1) and Histidine-tryptophan-ketoglutarate (HTK) solutions are proposed as alternatives to UW (gold standard) in liver preservation. Their composition differs in terms of the presence/absence of oncotic agents such as HES or PEG, and is decisive for graft conservation before transplantation. This is especially so when fatty (steatotic) livers are used since these grafts are more vulnerable to ischemia insult during conservation. Their composition determines the extent of the subsequent reperfusion injury after transplantation. Aldehyde dehydrogenase-2 (ALDH2), a mitochondrial enzyme, has been reported to play a protective role in warm ischemia-reperfusion injury (IRI), but its potential in fatty liver cold ischemic injury has not yet been investigated. We evaluated the relevance of ALDH2 activity in cold ischemia injury when fatty liver grafts from Zucker Obese rats were preserved in UW, HTK, and IGL-1 solutions, in order to study the mechanisms involved. ALDH2 upregulation was highest in livers preserved in IGL-1. It was accompanied by a decrease in transaminases, apoptosis (Caspase 3 and TUNEL assay), and lipoperoxidation, which was concomitant with the effective clearance of toxic aldehydes such as 4-hydroxy-nonenal. Variations in ATP levels were also determined. The results were consistent with levels of NF-E2 p45-related factor 2 (Nrf2), an antioxidant factor. Here we report for the first time the relevance of mitochondrial ALDH2 in fatty liver cold preservation and suggest that ALDH2 could be considered a potential therapeutic target or regulator in clinical transplantation.
Cytoprotective Mechanisms in Fatty Liver Preservation against Cold Ischemia Injury: A Comparison between IGL-1 and HTK
Institute Goeorges Lopez 1 (IGL-1) and Histidine-Tryptophan-Ketoglutarate (HTK) preservation solutions are regularly used in clinical for liver transplantation besides University of Wisconsin (UW) solution and Celsior. Several clinical trials and experimental works have been carried out comparing all the solutions, however the comparative IGL-1 and HTK appraisals are poor; especially when they deal with the underlying protection mechanisms of the fatty liver graft during cold storage. Fatty livers from male obese Zücker rats were conserved for 24 h at 4 °C in IGL-1 or HTK preservation solutions. After organ recovery and rinsing of fatty liver grafts with Ringer Lactate solution, we measured the changes in mechanistic target of rapamycin (mTOR) signaling activation, liver autophagy markers (Beclin-1, Beclin-2, LC3B and ATG7) and apoptotic markers (caspase 3, caspase 9 and TUNEL). These determinations were correlated with the prevention of liver injury (aspartate and alanine aminostransferase (AST/ALT), histology) and mitochondrial damage (glutamate dehydrogenase (GLDH) and confocal microscopy findings). Liver grafts preserved in IGL-1 solution showed a marked reduction on p-TOR/mTOR ratio when compared to HTK. This was concomitant with significant increased cyto-protective autophagy and prevention of liver apoptosis, including inflammatory cytokines such as HMGB1. Together, our results revealed that IGL-1 preservation solution better protected fatty liver grafts against cold ischemia damage than HTK solution. IGL-1 protection was associated with a reduced liver damage, higher induced autophagy and decreased apoptosis. All these effects would contribute to limit the subsequent extension of reperfusion injury after graft revascularization in liver transplantation procedures.
The Relevance of the UPS in Fatty Liver Graft Preservation: A New Approach for IGL-1 and HTK Solutions
The 26S proteasome is the central proteolytic machinery of the ubiquitin proteasome system (UPS), which is involved in the degradation of ubiquitinated protein substrates. Recently, UPS inhibition has been shown to be a key factor in fatty liver graft preservation during organ cold storage using University of Wisconsin solution (UW) and Institute Georges Lopez (IGL-1) solutions. However, the merits of IGL-1 and histidine-tryptophan-ketoglutarate (HTK) solutions for fatty liver preservation have not been compared. Fatty liver grafts from obese Zücker rats were preserved for 24 h at 4 °C. Aspartate aminotransferase and alanine aminotransferase (AST/ALT), glutamate dehydrogenase (GLDH), ATP, adenosine monophosphate protein kinase (AMPK), e-NOS, proteasome activity and liver polyubiquitinated proteins were determined. IGL-1 solution prevented ATP breakdown during cold-storage preservation of steatotic livers to a greater extent than HTK solution. There were concomitant increases in AMPK activation, e-NOS (endothelial NOS (NO synthase)) expression and UPS inhibition. UPS activity is closely related to the composition of the solution used to preserve the organ. IGL-1 solution provided significantly better protection against ischemia-reperfusion for cold-stored fatty liver grafts than HTK solution. The effect is exerted through the activation of the protective AMPK signaling pathway, an increase in e-NOS expression and a dysregulation of the UPS.
GSK3beta and VDAC involvement in ER stress and apoptosis modulation during orthotopic liver transplantation
We investigated the involvement of glycogen synthase kinase-3β (GSK3β) and the voltage-dependent anion channel (VDAC) in livers subjected to cold ischemia-reperfusion injury (I/R) associated with orthotopic liver transplantation (OLT). Rat livers were preserved in University of Wisconsin (UW) and Institute Georges Lopez (IGL-1) solution, the latter enriched or not with trimetazidine, and then subjected to OLT. Transaminase (ALT) and HMGB1 protein levels, glutamate dehydrogenase (GLDH), and oxidative stress (MDA) were measured. The AKT protein kinase and its direct substrates, GSK3β and VDAC, as well as caspases 3, 9, and cytochrome C and reticulum endoplasmic stress-related proteins (GRP78, pPERK, ATF4, and CHOP), were determined by Western blot. IGL-1+TMZ significantly reduced liver injury. We also observed a significant phosphorylation of AKT, which in turn induced the phosphorylation and inhibition of GSK3β. In addition, TMZ protected the mitochondria since, in comparison with IGL-1 alone, we found reductions in VDAC phosphorylation, apoptosis, and GLDH release. All these results were correlated with decreased ER stress. Addition of TMZ to IGL-1 solution increased the tolerance of the liver graft to I/R injury through inhibition of GSK3β and VDAC, contributing to ER stress reduction and cell death prevention.
Pretransplantation optimisation for unresectable colorectal liver metastases: the TransMet trial – Authors' reply
A Model for End-Stage Liver Disease-exception priority is, however, crucial for improving organ accessibility, as it is for hepatocellular carcinoma. 2 Concerning post-randomisation treatment, patients were treated in both groups by local teams according to international guidelines. Regarding locoregional treatments before transplantation, four (12%) patients had hepatectomy before liver transplantation (as reported in the appendix of the original Article 1) but others also received ablation or intra-arterial infusion to increase local control. 1 Less salvageability of recurrence in patients who received a transplant with partial living donor grafts compared with whole liver cadaveric grafts is likely, due to a lower amount of parenchyma; however, the poor prognosis of liver recurrence after liver transplantation could be the main point affecting outcome. 3 As suggested by Yi and colleagues, we agree that patients with non- BRAF V600E mutations should be included in future trials due to their better prognosis compared with patients with BRAF V600E mutations. 4 The 56·6% 5-year survival of the transplantation plus chemotherapy group was observed with intention to treat and included nine patients who did not receive a transplant. Among patients who did undergo transplantation (ie, the per-protocol population), the 5-year survival rate of 73% was nearer to the 83% 5-year survival rate reported in SECA-II, 5 which shows the robustness of liver transplantation irrespective of RAS mutations.
5-HT1A receptors on mature dentate gyrus granule cells are critical for the antidepressant response
Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants, but the mechanisms by which they influence behavior are only partially resolved. Using a combination of different approaches, the authors demonstrate that serotonin 1A receptors expressed in mature dentate gyrus granule cells are critical mediators of the response to SSRIs. Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants, but the mechanisms by which they influence behavior are only partially resolved. Adult hippocampal neurogenesis is necessary for some of the responses to SSRIs, but it is not known whether mature dentate gyrus granule cells (DG GCs) also contribute. We deleted the serotonin 1A receptor (5HT1AR, a receptor required for the SSRI response) specifically from DG GCs and found that the effects of the SSRI fluoxetine on behavior and the hypothalamic-pituitary-adrenal (HPA) axis were abolished. By contrast, mice lacking 5HT1ARs only in young adult-born GCs (abGCs) showed normal fluoxetine responses. Notably, 5HT1AR-deficient mice engineered to express functional 5HT1ARs only in DG GCs responded to fluoxetine, indicating that 5HT1ARs in DG GCs are sufficient to mediate an antidepressant response. Taken together, these data indicate that both mature DG GCs and young abGCs must be engaged for an antidepressant response.
The Near-infrared Imager and Slitless Spectrograph for the James Webb Space Telescope. II. Wide Field Slitless Spectroscopy
We present the wide field slitless spectroscopy mode of the NIRISS instrument on the James Webb Space Telescope. This mode employs two orthogonal low-resolution (resolving power ≈150) grisms in combination with a set of six blocking filters in the wavelength range 0.8–2.3 μ m to provide a spectrum of almost every source across the field-of-view. When combined with the low background, high sensitivity and high spatial resolution afforded by the telescope, this mode will enable unprecedented studies of the structure and evolution of distant galaxies. We describe the performance of the as-built hardware relevant to this mode and expected imaging and spectroscopic sensitivity. We discuss operational and calibration procedures to obtain the highest quality data. As examples of the observing mode usage, we present details of two planned Guaranteed Time Observations programs: The Canadian NIRISS Unbiased Cluster Survey and The NIRISS Survey for Young Brown Dwarfs and Rogue Planets.
An integrated genetic-epigenetic analysis of schizophrenia: evidence for co-localization of genetic associations and differential DNA methylation
Background Schizophrenia is a highly heritable, neuropsychiatric disorder characterized by episodic psychosis and altered cognitive function. Despite success in identifying genetic variants associated with schizophrenia, there remains uncertainty about the causal genes involved in disease pathogenesis and how their function is regulated. Results We performed a multi-stage epigenome-wide association study, quantifying genome-wide patterns of DNA methylation in a total of 1714 individuals from three independent sample cohorts. We have identified multiple differentially methylated positions and regions consistently associated with schizophrenia across the three cohorts; these effects are independent of important confounders such as smoking. We also show that epigenetic variation at multiple loci across the genome contributes to the polygenic nature of schizophrenia. Finally, we show how DNA methylation quantitative trait loci in combination with Bayesian co-localization analyses can be used to annotate extended genomic regions nominated by studies of schizophrenia, and to identify potential regulatory variation causally involved in disease. Conclusions This study represents the first systematic integrated analysis of genetic and epigenetic variation in schizophrenia, introducing a methodological approach that can be used to inform epigenome-wide association study analyses of other complex traits and diseases. We demonstrate the utility of using a polygenic risk score to identify molecular variation associated with etiological variation, and of using DNA methylation quantitative trait loci to refine the functional and regulatory variation associated with schizophrenia risk variants. Finally, we present strong evidence for the co-localization of genetic associations for schizophrenia and differential DNA methylation.
Liver transplantation plus chemotherapy versus chemotherapy alone in patients with permanently unresectable colorectal liver metastases (TransMet): results from a multicentre, open-label, prospective, randomised controlled trial
Despite the increasing efficacy of chemotherapy, permanently unresectable colorectal liver metastases are associated with poor long-term survival. We aimed to assess whether liver transplantation plus chemotherapy could improve overall survival. TransMet was a multicentre, open-label, prospective, randomised controlled trial done in 20 tertiary centres in Europe. Patients aged 18−65 years, with Eastern Cooperative Oncology Group performance score 0−1, permanently unresectable colorectal liver metastases from resected BRAF-non-mutated colorectal cancer responsive to systemic chemotherapy (≥3 months, ≤3 lines), and no extrahepatic disease, were eligible for enrolment. Patients were randomised (1:1) to liver transplantation plus chemotherapy or chemotherapy alone, using block randomisation. The liver transplantation plus chemotherapy group underwent liver transplantation for 2 months or less after the last chemotherapy cycle. At randomisation, the liver transplantation plus chemotherapy group received a median of 21·0 chemotherapy cycles (IQR 18·0−29·0) versus 17·0 cycles (12·0−24·0) in the chemotherapy alone group, in up to three lines of chemotherapy. During first-line chemotherapy, 64 (68%) of 94 patients had received doublet chemotherapy and 30 (32%) of 94 patients had received triplet regimens; 76 (80%) of 94 patients had targeted therapy. Transplanted patients received tailored immunosuppression (methylprednisolone 10 mg/kg intravenously on day 0; tacrolimus 0·1 mg/kg via gastric tube on day 0, 6−10 ng/mL days 1–14; mycophenolate mofetil 10 mg/kg intravenously day 0 to <2 months and switch to everolimus 5−8 ng/mL), and postoperative chemotherapy, and the chemotherapy group had continued chemotherapy. The primary endpoint was 5-year overall survival analysed in the intention to treat and per-protocol population. Safety events were assessed in the as-treated population. The study is registered with ClinicalTrials.gov (NCT02597348), and accrual is complete. Between Feb 18, 2016, and July 5, 2021, 94 patients were randomly assigned and included in the intention-to-treat population, with 47 in the liver transplantation plus chemotherapy group and 47 in the chemotherapy alone group. 11 patients in the liver transplantation plus chemotherapy group and nine patients in the chemotherapy alone group did not receive the assigned treatment; 36 patients and 38 patients in each group, respectively, were included in the per-protocol analysis. Patients had a median age of 54·0 years (IQR 47·0−59·0), and 55 (59%) of 94 patients were male and 39 (41%) were female. Median follow-up was 59·3 months (IQR 42·4−60·2). In the intention-to-treat population, 5-year overall survival was 56·6% (95% CI 43·2−74·1) for liver transplantation plus chemotherapy and 12·6% (5·2–30·1) for chemotherapy alone (HR 0·37 [95% CI 0·21−0·65]; p=0·0003) and 73·3% (95% CI 59·6–90·0) and 9·3% (3·2–26·8), respectively, for the per-protocol population. Serious adverse events occurred in 32 (80%) of 40 patients who underwent liver transplantation (from either group), and 69 serious adverse events were observed in 45 (83%) of 54 patients treated with chemotherapy alone. Three patients in the liver transplantation plus chemotherapy group were retransplanted, one of whom died postoperatively of multi-organ failure. In selected patients with permanently unresectable colorectal liver metastases, liver transplantation plus chemotherapy with organ allocation priority significantly improved survival versus chemotherapy alone. These results support the validation of liver transplantation as a new standard option for patients with permanently unresectable liver-only metastases. French National Cancer Institute and Assistance Publique–Hôpitaux de Paris.
A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task
Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide 12 easy-to-implement consensus recommendations and point out the problems that can arise when they are not followed. Furthermore, we provide user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis.