Different Effects of RNAi-Mediated Downregulation or Chemical Inhibition of NAMPT in an Isogenic IDH Mutant and Wild-Type Glioma Cell Model.

The IDH1R132H mutation in glioma results in the neoenzymatic function of IDH1, leading to the production of the oncometabolite 2-hydroxyglutarate (2-HG), alterations in energy metabolism and changes in the cellular redox household. Although shifts in the redox ratio NADPH/NADP+ were described, the consequences for the NAD+ synthesis pathways and potential therapeutic interventions were largely unexplored. Here, we describe the effects of heterozygous IDH1R132H on the redox system in a CRISPR/Cas edited glioblastoma model and compare them with IDH1 wild-type (IDH1wt) cells. Besides an increase in 2-HG and decrease in NADPH, we observed an increase in NAD+ in IDH1R132H glioblastoma cells. RT-qPCR analysis revealed the upregulation of the expression of the NAD+ synthesis enzyme nicotinamide phosphoribosyltransferase (NAMPT). Knockdown of NAMPT resulted in significantly reduced viability in IDH1R132H glioblastoma cells. Given this dependence of IDH1R132H cells on NAMPT expression, we explored the effects of the NAMPT inhibitors FK866, GMX1778 and GNE-617. Surprisingly, these agents were equally cytotoxic to IDH1R132H and IDH1wt cells. Altogether, our results indicate that targeting the NAD+ synthesis pathway is a promising therapeutic strategy in IDH mutant gliomas; however, the agent should be carefully considered since three small-molecule inhibitors of NAMPT tested in this study were not suitable for this purpose.

EUS-guided stent removal in buried lumen-apposing metal stent syndrome: a case series.

BACKGROUND AND AIMS: Lumen-apposing metal stents (LAMSs) play an increasing role in transgastric and transduodenal drainage of pancreatic fluid collections and allow novel EUS-guided interventions. Alongside the main adverse events of bleeding and occlusion, LAMSs can be overgrown by mucosa, which leads to the inability to visualize the stent in endoscopy. METHODS: We describe a series of 4 cases of buried LAMSs that were removed under EUS guidance for identification of the stent followed by removal with rat-tooth forceps. RESULTS: The median in situ time of the LAMSs in the reported 4 cases was 53 days. All stents could no longer be visualized endoscopically when drainage of necrosis was complete. All 4 buried LAMSs could be identified by EUS and were removed successfully with forceps. In 1 case, balloon dilation of the stent tract was performed before stent removal. No adverse events were observed after the procedure. CONCLUSIONS: Buried stent syndrome is a rare adverse event of LAMSs. Here we describe a safe and effective approach for stent identification and removal without prior mucosal dissection.

Effectiveness and safety of vedolizumab in inflammatory bowel disease patients aged 60 and over: an observational multicenter UK experience.

BACKGROUND: The GEMINI trials established the efficacy of vedolizumab in moderate-to-severe inflammatory bowel disease (IBD) and demonstrated a favorable safety profile, suggesting it may be advantageous in older patients at greater risk of treatment-related complications. However, there is a paucity of data exploring the outcomes of vedolizumab in this group. Our objective was to determine the clinical effectiveness and safety of vedolizumab in older IBD patients within a real-world multicenter UK cohort. METHODS: A retrospective review of electronic records across 6 UK hospitals was undertaken to evaluate the clinical effectiveness and safety outcomes of vedolizumab in IBD patients aged ≥60 at start of therapy. Rates of clinical response, remission and corticosteroid-free remission were assessed at weeks 14 and 52, using validated clinical indices, and were compared to historical controls from real-world vedolizumab-treated cohorts unstratified by age. RESULTS: Of 74 patients aged 60 years or above (median 66 years), 48 were included in our effectiveness analysis (29 ulcerative colitis, 19 Crohn's disease). Rates of clinical response, remission and corticosteroid-free remission at week 14 were 64%, 48% and 30%, respectively. By week 52, the rates of clinical response, remission, and corticosteroid-free remission were 52%, 38%, and 32%, respectively. Six (8%) patients experienced adverse effects. Effectiveness and safety outcomes were comparable to those of age-unstratified vedolizumab-treated cohorts. CONCLUSION: Our 1-year outcome data suggests that vedolizumab is safe and effective in older IBD patients and broadly comparable to cohorts unselected by age.

Mutant IDH1 Differently Affects Redox State and Metabolism in Glial Cells of Normal and Tumor Origin.

IDH1R132H (isocitrate dehydrogenase 1) mutations play a key role in the development of low-grade gliomas. IDH1wt converts isocitrate to α-ketoglutarate while reducing nicotinamide adenine dinucleotide phosphate (NADP+), whereas IDH1R132H uses α-ketoglutarate and NADPH to generate the oncometabolite 2-hydroxyglutarate (2-HG). While the effects of 2-HG have been the subject of intense research, the 2-HG independent effects of IDH1R132H are still ambiguous. The present study demonstrates that IDH1R132H expression but not 2-HG alone leads to significantly decreased tricarboxylic acid (TCA) cycle metabolites, reduced proliferation, and enhanced sensitivity to irradiation in both glioblastoma cells and astrocytes in vitro. Glioblastoma cells, but not astrocytes, showed decreased NADPH and NAD+ levels upon IDH1R132H transduction. However, in astrocytes IDH1R132H led to elevated expression of the NAD-synthesizing enzyme nicotinamide phosphoribosyltransferase (NAMPT). These effects were not 2-HG mediated. This suggests that IDH1R132H cells utilize NAD+ to restore NADP pools, which only astrocytes could compensate via induction of NAMPT. We found that the expression of NAMPT is lower in patient-derived IDH1-mutant glioma cells and xenografts compared to IDH1-wildtype models. The Cancer Genome Atlas (TCGA) data analysis confirmed lower NAMPT expression in IDH1-mutant versus IDH1-wildtype gliomas. We show that the IDH1 mutation directly affects the energy homeostasis and redox state in a cell-type dependent manner. Targeting the impairments in metabolism and redox state might open up new avenues for treating IDH1-mutant gliomas.