Docosahexanoic acid antagonizes TNF-α-induced necroptosis by attenuating oxidative stress,ceramide production,lysosomal dysfunction,and autophagic features

Objective

It was previously reported that docosahexanoic acid (DHA) reduces TNF-α-induced necrosis in L929 cells. However, the mechanisms underlying this reduction have not been investigated. The present study was designed to investigate cellular and biochemical mechanisms underlying the attenuation of TNF-α-induced necroptosis by DHA in L929 cells.

Methods

L929 cells were pre-treated with DHA prior to exposure to TNF-α, zVAD, or Necrostatin-1 (Nec-1). Cell death and survival were assessed by MTT and caspase activity assays, and microscopic visualization. Reactive oxygen species (ROS) were measured by flow cytometry. C16- and C18-ceramides were measured by mass spectrometry. Lysosomal membrane permeabilization (LMP) was evaluated by fluorescence microscopy and flow cytometry using Acridine Orange. Cathepsin L activation was evaluated by immunoblotting and fluorescence microscopy. Autophagy was assessed by immunoblotting of LC3-II and Beclin.

Results

Exposure of L929 cells to TNF-α alone for 24 h induced necroptosis, as evidenced by the inhibition of cell death by Nec-1, absence of caspase-3 activity and Lamin B cleavage, and morphological analysis. DHA attenuated multiple biochemical events associated with TNF-α-induced necroptosis, including ROS generation, ceramide production, lysosomal dysfunction, cathepsin L activation, and autophagic features. DHA also attenuated zVAD-induced necroptosis but did not attenuate the enhanced apoptosis and necrosis induced by the combination of TNF-α with Actinomycin D or zVAD, respectively, suggesting that its protective effects might be limited by the strength of the cell death insult induced by TNF-α.

Conclusions

DHA effectively attenuates TNF-α-induced necroptosis and autophagy, most likely via its ability to inhibit TNF-α-induced sphingolipid metabolism and oxidative stress. These results highlight the role of this Omega-3 fatty acid in antagonizing inflammatory cell death.     

Regulation and functional effects of ZNT8 in human pancreatic islets

Zinc ions are essential for the formation of insulin crystals in pancreatic β cells, thereby contributing to packaging efficiency of stored insulin. Zinc fluxes are regulated through the SLC30A (zinc transporter, ZNT) family. Here, we investigated the effect of metabolic stress associated with the prediabetic state (zinc depletion, glucotoxicity, and lipotoxicity) on ZNT expression and human pancreatic islet function. Both zinc depletion and lipotoxicity (but not glucotoxicity) downregulated ZNT8 (SLC30A8) expression and altered the glucose-stimulated insulin secretion index (GSIS). ZNT8 overexpression in human islets protected them from the decrease in GSIS induced by tetrakis-(2-pyridylmethyl) ethylenediamine and palmitate but not from cell death. In addition, zinc supplementation decreased palmitate-induced human islet cell death without restoring GSIS. Altogether, we showed that ZNT8 expression responds to variation in zinc and lipid levels in human β cells, with repercussions on insulin secretion. Prospects for increasing ZNT8 expression and/or activity may prove beneficial in type 2 diabetes in humans.     

Targeted profiling of atherogenic phospholipids in human plasma and lipoproteins of hyperlipidemic patients using MALDI-QIT-TOF-MS/MS

ObjectivesPhospholipids (PLs) are increasingly recognized as key molecules with potential diagnostic value in acute inflammation, CVD and atherosclerosis. We introduce a pioneer mass spectrometry (MS)-based approach aiming to investigate the relationship of specific plasma PL-subsets with atherogenic blood parameters in young patients with familial hyperlipidemia representing high-CVD-risk groups.MethodsPlasma of carefully phenotyped FH and FCH patients as well as normolipidemic subjects (age 13 ± 5 years, n = 20) was used. Clinical parameters were assessed using standard laboratory techniques and lipids were subjected to a direct targeted monitoring using LC-ESI-SRM- and MALDI-QIT-TOF-MS/MS, respectively. Statistical analysis was performed to evaluate correlations between PL data and the clinical parameters.ResultsMost characteristically significant differences of SM/PC and PC/LPC ratios and positive correlations between SM vs. LDL-C (r = 0.946; p = 0.004) and LPC vs. VLDL-C (r = 0.669; p = 0.218) were observed in FH in contrast to the other study groups. OxPC levels were found in the range of ～2–20 μmol/L with predominance of short-chain aldehydic species (e.g. SOVPC). A positive correlation of OxPCs with IMT (r = 0.952; p = 0.052) and HDL-C (r = 0.893; p = 0.016) but negative correlation with OxLDL (r = ?0.910; p = 0.096) was observed.ConclusionsOur study was a first attempt to use a MALDI-QIT-TOF-MS/MS based clinical lipidomics approach to investigate atherogenic dyslipidemia in young patients with familial hyperlipidemia. This technique represents a promising platform for clinical screening of lipid biomarkers in the future.     

Partial deletion of ANKRD11 results in the KBG phenotype distinct from the 16q24.3 microdeletion syndrome

KBG syndrome (OMIM 148050) is a very rare genetic disorder characterized by macrodontia, distinctive craniofacial abnormalities, short stature, intellectual disability, skeletal, and neurologic involvement. Approximately 60 patients have been reported since it was first described in 1975. Recently mutations in ANKRD11 have been documented in patients with KBG syndrome, and it has been proposed that haploinsufficiency of ANKRD11 is the cause of this syndrome. In addition, copy number variation in the 16q24.3 region that includes ANKRD11 results in a variable phenotype that overlaps with KBG syndrome and also includes autism spectrum disorders and other dysmorphic facial features. In this report we present a 2½‐year‐old African American male with features highly suggestive of KBG syndrome. Genomic microarray identified an intragenic 154 kb deletion at 16q24.3 within ANKRD11. This child's mother was mosaic for the same deletion (present in approximately 38% of cells) and exhibited a milder phenotype including macrodontia, short stature and brachydactyly. This family provides additional evidence that ANKRD11 causes KBG syndrome, and the mild phenotype in the mosaic form suggests that KBG phenotypes might be dose dependent, differentiating it from the more variable 16q24.3 microdeletion syndrome. This family has additional features that might expand the phenotype of KBG syndrome. © 2013 Wiley Periodicals, Inc.     

Hybrid fluorescent liquid crystalline composites: directed assembly of quantum dots in liquid crystalline block copolymer matrices

Hybrid fluorescent liquid crystalline (LC) composites containing inorganic quantum dots (QDs) are promising materials for many applications in optics, nanophotonics and display technology, combining the superior emission capability of QDs with the externally controllable optical properties of LCs. In this work, we propose the hybrid LC composites that were obtained by embedding CdSe/ZnS QDs into a series of host LC block copolymers of different architectures by means of a two-stage ligand exchange procedure. The ABA/BAB triblock copolymers and AB diblock copolymers with different polymerization degrees are composed of nematogenic phenyl benzoate acrylic monomer units and poly(4-vinylpyridine) blocks, which are capable of binding to the QD surface. Our results clearly show that the spatial distribution of QDs within composite films as well as the formation of QD aggregates can be programed by varying the structure of the host block copolymer. The obtained composites form a nematic LC phase, with isotropization temperatures being close to those of the initial host block copolymers. In addition, the influence of the molecular architecture of the host block copolymers on fluorescence properties of the obtained composites is considered. The described strategy for the QD assembly should provide a robust and conventional route for the design of highly ordered hierarchical hybrid materials for many practical applications.

Spatial distribution of QDs within hybrid composite films was programed by varying the molecular architecture of the host LC block copolymers.     

Why are we Still Dialyzing Overdoses to Tricyclic Antidepressants? A subanalysis of the NPDS database

A recent analysis of the American Association of Poison Control Centers database, showed that poisonings from toxins not usually considered amenable to extracorporeal purification (“non‐classic toxins” such as ethanol and tricyclic antidepressants) continue to be reported. This publication investigates factors that may explain these findings. Our results suggest that: 1) the relatively high absolute number of ECTR performed for non‐classic toxins may simply reflect the large number of exposures to these toxins, 2) poisoning from another toxin may have been the reason for ECTR initiation in some exposures to non‐classic toxins, 3) poisoning from non‐classic toxins may receive ECTR for purposes other than toxin removal, and 4) the decisional threshold to initiate ECTR may be lower for non‐classic toxins because of heightened toxicity.     

Aluminum transfer during dialysis: a systematic review

Purpose

Dialysis-dependent patients are particularly susceptible to the toxic effects of aluminum (Al) because of their impaired ability to eliminate it. Al contamination of dialysis fluid remains a threat in this population. The mechanism for Al diffusion across dialysis membranes is not well established. Our objective is to verify, in AL-exposed patients, the postulate that the direction of Al transfer is predicted by the concentration gradient between free diffusible plasma Al and dialysate Al.

Methods

A systematic review of the literature was performed. Only papers which included Al plasma concentration ([Al]p), Al dialysate concentration ([Al]d) and direction of Al transfer (positive = from dialysate to plasma, negative = from plasma to dialysate) were selected. We also included four patients from our own cohort. Assuming that [Al]p has an ultrafiltrable fraction between 17 and 23 %, cases were considered in keeping with our hypothesis if any of the following scenarios was present: negative Al transfer when [Al]d < [Al]p*23 % and positive Al transfer when [Al]d > [Al]p*17 %.

Results

The search yielded 409 articles, of which 12 were selected for review. When reviewing individual patients for analysis, 108 out of 115 (94 %) patients followed our hypothesis. By further excluding cases in which Al transfer could not be determined, only three out of 111 patients were contrary to out hypothesis.

Conclusion

Comparing ultrafiltrable Al to dialysate Al permits to accurately predict the direction of Al transfer. The optimal [Al]d should be <20 % of the maximally acceptable [Al]p. In order to follow K/DOQI guidelines ([Al]p < 20 μg/L), the [Al]d should therefore not exceed 4 μg/L. At the level presently supported by K/DOQI ([Al]d < 10 μg/L), [Al]p could realistically reach 50 μg/L and potentially cause toxicity.     

Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy: A Feasible and Effective Option for Colorectal Cancer Patients After Emergency Surgery in the Presence of Peritoneal Carcinomatosis

Background

When peritoneal carcinomatosis (PC) is diagnosed during emergency surgery for colorectal cancer (CRC), further treatment with curative intent may seem futile given the known poor prognosis of both PC and emergency surgery. The aim of the current study was to investigate the feasibility and effectiveness of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for CRC patients who previously underwent emergency surgery in the presence of PC.

Methods

All patients with synchronous PC of CRC referred to two tertiary centers between April 2005 and November 2013 were included in this study. Operative, postoperative and survival details were compared between patients presenting in an emergency or elective setting.

Results

In total, 149 patients with synchronous PC underwent CRS and HIPEC. Amongst these patients, 36 (24.2 %) initially presented with acute symptoms requiring emergency surgery. Acute presentation did not result in a longer interval between the initial operation and HIPEC (2.2 vs. 2.1 months; P = 0.09). When comparing operative outcomes, no significant differences were found in blood loss (P = 0.47), operation time (P = 0.39), or completeness of cytoreduction (P = 0.97). In addition, complication rates, degree and types of complication did not differ between the groups. Median survival was 36.1 months for emergency presentation compared with 32.1 in the elective group (P = 0.73).

Conclusion

CRS + HIPEC may be performed safely in patients with PC of colorectal origin presenting with acute symptoms requiring emergency surgery. More importantly, the 5-year survival rate in these patients was equal to elective cases. This should be regarded as promising and therefore considered for these patients.     

Pancreatic steatosis on computed tomography is an early imaging feature of pre-diagnostic pancreatic cancer: A preliminary study in overweight patients

BackgroundThe prevalence of pancreatic ductal adenocarcinoma (PDAC) is on the rise, driven by factors such as aging and an increasing prevalence of obesity and diabetes mellitus. To improve the poor survival rate of PDAC, early detection is vital. Recently, pancreatic steatosis has gained novel interest as a risk factor for PDAC. This study aimed to investigate if pancreatic steatosis on computed tomography (CT) is an early imaging feature in patients with pre-diagnostic PDAC.MethodsA retrospective case-control study was performed. Patients diagnosed with PDAC (2010–2016) were reviewed for abdominal non-contrast CT-imaging 1 month-3 years prior to their diagnosis. Cases were matched 1:4 with controls based on age, gender and imaging date. Unenhanced CT-images were evaluated for pancreatic steatosis (pancreas-to-spleen ratio in Hounsfield Units <0.70) by a blinded radiologist and results were compared between cases and controls.ResultsIn total, 32 cases and 117 controls were included in the study with a comparable BMI (29.6 and 29.2 respectively, p = 0.723). Pancreatic steatosis was present in 71.9% of cases compared to 45.3% of controls (Odds ratio (OR) 3.09(1.32–7.24), p = 0.009). Adjusted for BMI and diabetes mellitus, pancreatic steatosis on CT remained a significant independent risk factor for PDAC (Adjusted OR 2.70(1.14–6.58), p = 0.037).ConclusionPancreatic steatosis measured on CT is independently associated with PDAC up to three years before the clinical diagnosis in overweight patients. If these data are confirmed, this novel imaging feature may be used to identify high-risk individuals and to stratify the risk of PDAC in individuals that already undergo PDAC screening.