Mortality Risk Factors Among Patients With Cirrhosis and a Low Model for End-Stage Liver Disease Sodium Score (≤15): An Analysis of Liver Transplant Allocation Policy Using Aggregated Electronic Health Record Data

Although the Model for End-Stage Liver Disease sodium (MELD Na) score is now used for liver transplant allocation in the United States, mortality prediction may be underestimated by the score. Using aggregated electronic health record data from 7834 adult patients with cirrhosis, we determined whether the cause of cirrhosis or cirrhosis complications was associated with an increased risk of death among patients with a MELD Na score ≤15 and whether patients with the greatest risk of death could benefit from liver transplantation (LT). Over median follow-up of 2.3 years, 3715 patients had a maximum MELD Na score ≤15. Overall, 3.4% were waitlisted for LT. Severe hypoalbuminemia, hepatorenal syndrome, and hepatic hydrothorax conferred the greatest risk of death independent of MELD Na score with 1-year predicted mortality >14%. Approximately 10% possessed these risk factors. Of these high-risk patients, only 4% were waitlisted for LT, despite no difference in nonliver comorbidities between waitlisted patients and those not listed. In addition, risk factors for death among waitlisted patients were the same as those for patients not waitlisted, although the effect of malnutrition was significantly greater for waitlisted patients (hazard ratio 8.65 [95% CI 2.57-29.11] vs. 1.47 [95% CI 1.08-1.98]). Using the MELD Na score for allocation may continue to limit access to LT.

Surgical repair of annulus defect with biomimetic multilamellar nano/microfibrous scaffold in a porcine model

Annulus defect is associated with reherniation and disc degeneration after discectomy; currently there is no effective treatment that addresses this problem. The annulus is a hierarchical lamellar structure, where each lamella consists of aligned collagen fibres, which are parallel and tilted at 30° to the spinal axis. In this study, a biomimetic biodegradable scaffold consisting of multilamellar nano/microfibres, sharing nanotopography and microporosity similar to the native lamellar structure, was assessed in a porcine model, aided by sealing with fascia and medical glue and subsequent suture fixation. After 6- and 12-week observation, we found that this treatment restored nucleus volume and slowed down disc degeneration, as indicated by magnetic resonance imaging of T1/T2-weighted, T2-mapping, T1-ρ imaging. Histological analysis showed aligned collagen fibres organized in the scaffold and integrated with surrounding native annulus tissue. The autologous bone marrow concentrate-seeded scaffolds showed slightly earlier collagen fibre formation at 6 weeks. This novel treatment could efficiently close the annulus defect with newly formed, organized and integrated collagen fibres in a porcine model. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment of Posttranslational Modifications of ATG proteins

Posttranslational modifications (PTMs) increase the functional diversity of proteins and play a key role in many cellular processes. Macroautophagy (hereafter simply referred to as autophagy) is an evolutionarily conserved, lysosome-dependent degradation pathway. This process is finely regulated by autophagy-related (ATG) genes widely conserved among eukaryotes from yeast to mammals. Various PTMs of ATG proteins such as phosphorylation, ubiquitination, and acetylation have been theorized to play a critical role in modulating autophagic processes and activity. In this chapter, we introduce several antibody-based tools (e.g., Western blot, Simple Western™, immunofluorescence, and immunoprecipitation) that are widely used to assess the PTMs of ATG proteins in mammalian cells.

Factors Associated With Major Adverse Cardiovascular Events After Liver Transplantation Among a National Sample

Assessment of major adverse cardiovascular events (MACE) after liver transplantation (LT) has been limited by the lack of a multicenter study with detailed clinical information. An integrated database linking information from the University HealthSystem Consortium and the Organ Procurement and Transplant Network was analyzed using multivariate Poisson regression to assess factors associated with 30- and 90-day MACE after LT (February 2002 to December 2012). MACE was defined as myocardial infarction (MI), heart failure (HF), atrial fibrillation (AF), cardiac arrest, pulmonary embolism, and/or stroke. Of 32 810 recipients, MACE hospitalizations occurred in 8% and 11% of patients at 30 and 90 days, respectively. Recipients with MACE were older and more likely to have a history of nonalcoholic steatohepatitis (NASH), alcoholic cirrhosis, MI, HF, stroke, AF and pulmonary and chronic renal disease than those without MACE. In multivariable analysis, age >65 years (incidence rate ratio [IRR] 2.8, 95% confidence interval [95% CI] 1.8-4.4), alcoholic cirrhosis (IRR 1.6, 95% CI 1.2-2.2), NASH (IRR 1.6, 95% CI 1.1-2.4), pre-LT creatinine (IRR 1.1, 95% CI 1.04-1.2), baseline AF (IRR 6.9, 95% CI 5.0-9.6) and stroke (IRR 6.3, 95% CI 1.6-25.4) were independently associated with MACE. MACE was associated with lower 1-year survival after LT (79% vs. 88%, p < 0.0001). In a national database, MACE occurred in 11% of LT recipients and had a negative impact on survival. Pre-LT AF and stroke substantially increase the risk of MACE, highlighting potentially high-risk LT candidates.

Ferroptosis: process and function

Ferroptosis is a recently recognized form of regulated cell death. It is characterized morphologically by the presence of smaller than normal mitochondria with condensed mitochondrial membrane densities, reduction or vanishing of mitochondria crista, and outer mitochondrial membrane rupture. It can be induced by experimental compounds (e.g., erastin, Ras-selective lethal small molecule 3, and buthionine sulfoximine) or clinical drugs (e.g., sulfasalazine, sorafenib, and artesunate) in cancer cells and certain normal cells (e.g., kidney tubule cells, neurons, fibroblasts, and T cells). Activation of mitochondrial voltage-dependent anion channels and mitogen-activated protein kinases, upregulation of endoplasmic reticulum stress, and inhibition of cystine/glutamate antiporter is involved in the induction of ferroptosis. This process is characterized by the accumulation of lipid peroxidation products and lethal reactive oxygen species (ROS) derived from iron metabolism and can be pharmacologically inhibited by iron chelators (e.g., deferoxamine and desferrioxamine mesylate) and lipid peroxidation inhibitors (e.g., ferrostatin, liproxstatin, and zileuton). Glutathione peroxidase 4, heat shock protein beta-1, and nuclear factor erythroid 2-related factor 2 function as negative regulators of ferroptosis by limiting ROS production and reducing cellular iron uptake, respectively. In contrast, NADPH oxidase and p53 (especially acetylation-defective mutant p53) act as positive regulators of ferroptosis by promotion of ROS production and inhibition of expression of SLC7A11 (a specific light-chain subunit of the cystine/glutamate antiporter), respectively. Misregulated ferroptosis has been implicated in multiple physiological and pathological processes, including cancer cell death, neurotoxicity, neurodegenerative diseases, acute renal failure, drug-induced hepatotoxicity, hepatic and heart ischemia/reperfusion injury, and T-cell immunity. In this review, we summarize the regulation mechanisms and signaling pathways of ferroptosis and discuss the role of ferroptosis in disease.

The receptor for advanced glycation end products (RAGE) enhances autophagy and neutrophil extracellular traps in pancreatic cancer

Neutrophil extracellular traps (NETs) are formed when neutrophils expel their DNA, histones and intracellular proteins into the extracellular space or circulation. NET formation is dependent on autophagy and is mediated by citrullination of histones to allow for unwinding and subsequent expulsion of DNA. NETs play an important role in the pathogenesis of several sterile inflammatory diseases, including malignancy, therefore we investigated the role of NETs in the setting of pancreatic ductal adenocarcinoma (PDA). Neutrophils isolated from two distinct animal models of PDA had an increased propensity to form NETs following stimulation with platelet activating factor (PAF). Serum DNA, a marker of circulating NET formation, was elevated in tumor bearing animals as well as in patients with PDA. Citrullinated histone H3 expression, a marker of NET formation, was observed in pancreatic tumors obtained from murine models and patients with PDA. Inhibition of autophagy with chloroquine or genetic ablation of RAGE resulted in decreased propensity for NET formation, decreased serum DNA, and decreased citrullinated histone H3 expression in the pancreatic tumor microenvironment. We conclude that NETs are upregulated in pancreatic cancer through RAGE dependent/autophagy pathways.

HSPB1 as a novel regulator of ferroptotic cancer cell death

Ferroptosis is an iron-dependent form of non-apoptotic cell death, but its molecular mechanism remains largely unknown. Here, we demonstrate that heat shock protein beta-1 (HSPB1) is a negative regulator of ferroptotic cancer cell death. Erastin, a specific ferroptosis-inducing compound, stimulates heat shock factor 1 (HSF1)-dependent HSPB1 expression in cancer cells. Knockdown of HSF1 and HSPB1 enhances erastin-induced ferroptosis, whereas heat shock pretreatment and overexpression of HSPB1 inhibits erastin-induced ferroptosis. Protein kinase C-mediated HSPB1 phosphorylation confers protection against ferroptosis by reducing iron-mediated production of lipid reactive oxygen species. Moreover, inhibition of the HSF1-HSPB1 pathway and HSPB1 phosphorylation increases the anticancer activity of erastin in human xenograft mouse tumor models. Our findings reveal an essential role for HSPB1 in iron metabolism with important effects on ferroptosis-mediated cancer therapy.

RAGE is essential for oncogenic KRAS-mediated hypoxic signaling in pancreatic cancer

A hypoxic tumor microenvironment is characteristic of many cancer types, including one of the most lethal, pancreatic cancer. We recently demonstrated that the receptor for advanced glycation end products (RAGE) has an important role in promoting the development of pancreatic cancer and attenuating the response to chemotherapy. We now demonstrate that binding of RAGE to oncogenic KRAS facilitates hypoxia-inducible factor 1 (HIF1)α activation and promotes pancreatic tumor growth under hypoxic conditions. Hypoxia induces NF-κB-dependent and HIF1α-independent RAGE expression in pancreatic tumor cells. Moreover, the interaction between RAGE and mutant KRAS increases under hypoxia, which in turn sustains KRAS signaling pathways (RAF-MEK-ERK and PI3K-AKT), facilitating stabilization and transcriptional activity of HIF1α. Knock down of RAGE in vitro inhibits KRAS signaling, promotes HIF1α degradation, and increases hypoxia-induced pancreatic tumor cell death. RAGE-deficient mice have impaired oncogenic KRAS-driven pancreatic tumor growth with significant downregulation of the HIF1α signaling pathway. Our results provide a novel mechanistic link between NF-κB, KRAS, and HIF1α, three potent molecular pathways in the cellular response to hypoxia during pancreatic tumor development and suggest alternatives for preventive and therapeutic strategies.

Release and activity of histone in diseases

Histones and their post-translational modifications have key roles in chromatin remodeling and gene transcription. Besides intranuclear functions, histones act as damage-associated molecular pattern molecules when they are released into the extracellular space. Administration of exogenous histones to animals leads to systemic inflammatory and toxic responses through activating Toll-like receptors and inflammasome pathways. Anti-histone treatment (e.g., neutralizing antibodies, activated protein C, recombinant thrombomodulin, and heparin) protect mice against lethal endotoxemia, sepsis, ischemia/reperfusion injury, trauma, pancreatitis, peritonitis, stroke, coagulation, and thrombosis. In addition, elevated serum histone and nucleosome levels have been implicated in multiple pathophysiological processes and progression of diseases including autoimmune diseases, inflammatory diseases, and cancer. Therefore, extracellular histones could serve as biomarkers and novel therapeutic targets in human diseases.

The HMGB1/RAGE inflammatory pathway promotes pancreatic tumor growth by regulating mitochondrial bioenergetics

Tumor cells require increased adenosine triphosphate (ATP) to support anabolism and proliferation. The precise mechanisms regulating this process in tumor cells are unknown. Here, we show that the receptor for advanced glycation endproducts (RAGE) and one of its primary ligands, high-mobility group box 1 (HMGB1), are required for optimal mitochondrial function within tumors. We found that RAGE is present in the mitochondria of cultured tumor cells as well as primary tumors. RAGE and HMGB1 coordinately enhanced tumor cell mitochondrial complex I activity, ATP production, tumor cell proliferation and migration. Lack of RAGE or inhibition of HMGB1 release diminished ATP production and slowed tumor growth in vitro and in vivo. These findings link, for the first time, the HMGB1-RAGE pathway with changes in bioenergetics. Moreover, our observations provide a novel mechanism within the tumor microenvironment by which necrosis and inflammation promote tumor progression.

Strange attractors: DAMPs and autophagy link tumor cell death and immunity

Resistance to ‘apoptotic' cell death is one of the major hallmarks of cancer, contributing to tumor development and therapeutic resistance. Damage-associated molecular patterns (DAMPs) are molecules released or exposed by dead, dying, injured, or stressed non-apoptotic cells, with multiple roles in inflammation and immunity. Release of DAMPs not only contributes to tumor growth and progression but also mediates skewing of antitumor immunity during so-called immunogenic tumor cell death (ICD). Autophagy is a lysosome-mediated homeostatic degradation process in which cells digest their own effete organelles and macromolecules to meet bioenergetic needs and enable protein synthesis. For tumor cells, autophagy is a double-edged sword. Autophagy, in balance with apoptosis, can function as a tumor suppressor; autophagy deficiency, associated with alterations in apoptosis, initiates tumorigenesis in many settings. In contrast, autophagy-related stress tolerance generally promotes cell survival, which enables tumor growth and promotes therapeutic resistance. Most anticancer therapies promote DAMP release and enhance autophagy. Autophagy not only regulates DAMP release and degradation, but also is triggered and regulated by DAMPs. This interplay between autophagy and DAMPs, serving as ‘strange attractors' in the dynamic system that emerges in cancer, regulates the effectiveness of antitumor treatment. This interplay also shapes the immune response to dying cells upon ICD, culling the least fit tumor cells and promoting survival of others. Thus, DAMPs and autophagy are suitable emergent targets for cancer therapy, considering their more nuanced role in tumor progression.

Effect of age on atherogenicity of LDL and inflammatory markers in healthy women

BACKGROUND AND AIM

Since using LDL level alone is insufficient as a method to identify individuals with incident coronary artery disease (CAD), other factors may be implicated in the pathogenesis of CAD. Additionally, controversy still remains regarding whether there is an age-related increase in circulating cytokines in healthy individuals. We investigated the influence of age on atherogenicity of LDL and inflammatory markers in healthy women.

METHODS AND RESULTS

Two thousand nine hundred forty four healthy women form 30-79 years old (23.3 ± 0.05 kg/m²) were categorized into 5 age groups: 30-39, 40-49, 50-59, 60-69 and 70-79 years. BMI, smoking, drinking, and metabolic syndrome prevalence adjusted mean values of total-cholesterol progressively increased from the group age 30-39 years to the group age 40-49 and 50-59 years and thereafter decreased in the group age 60-69 and 70-79 years. Serum concentrations of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were higher in women aged 60-79 years than women aged 30-59 years. Plasma ox-LDL levels increased in the group age 50-59 years compared with the group age 30-39 and 40-49 years and further increased in the group age 60-69 and 70-79 years. Mean values of LDL particle size were smaller in women aged 60-79 years than those in women aged 30-59 years. After adjustment for BMI, smoking, drinking, and metabolic syndrome status, age was positively correlated with LDL-cholesterol (r = 0.095, P < 0.001), oxidized LDL (r = 0.305, P < 0.001), hs-CRP (r = 0.150, P < 0.001), TNF-α (r = 0.171, P < 0.001) and IL-6 (r = 0.294, P < 0.001) and negatively with LDL particle size (r = -0.239, P < 0.001).

CONCLUSION

Our results indicate that LDL atherogenicity and inflammatory mediators can be better markers of CAD risk than known risk factors such as elevated concentrations of total- and LDL-cholesterol, decreased HDL-cholesterol levels and smoking in old healthy women.

Targeting microRNA-30a-mediated autophagy enhances imatinib activity against human chronic myeloid leukemia cells

A major advancement in the treatment of chronic myeloid leukemia (CML) has been the development of imatinib and other BCR-ABL tyrosine kinase inhibitors. MicroRNAs (miRNAs) are small RNA molecules that influence gene expression by post-transcriptional regulation of messenger RNA. It is not yet clear how miRNAs are able to regulate the effectiveness of imatinib in CML. Here, we show that imatinib markedly inhibits expression of miR-30a in human CML cells. miR-30a is a potent inhibitor of autophagy by downregulating Beclin 1 and ATG5 expression. miR-30a mimic or knockdown of autophagy genes (ATGs) such as Beclin 1 and ATG5 by short hairpin RNA enhances imatinib-induced cytotoxicity and promotes mitochondria-dependent intrinsic apoptosis. In contrast, knockdown of miR-30a by antagomir-30a increases the expression of Beclin 1 and ATG5, and inhibits imatinib-induced cytotoxicity. These findings indicate that dysregulation of miR-30a may interfere with the effectiveness of imatinib-mediated apoptosis by an autophagy-dependent pathway, thus representing a novel potential therapeutic target in CML.