Cellular and Molecular Signatures of Oxidative Stress in Bronchial Epithelial Cell Models Injured by Cigarette Smoke Extract

Exposure of the airways epithelium to environmental insults, including cigarette smoke, results in increased oxidative stress due to unbalance between oxidants and antioxidants in favor of oxidants. Oxidative stress is a feature of inflammation and promotes the progression of chronic lung diseases, including Chronic Obstructive Pulmonary Disease (COPD). Increased oxidative stress leads to exhaustion of antioxidant defenses, alterations in autophagy/mitophagy and cell survival regulatory mechanisms, thus promoting cell senescence. All these events are amplified by the increase of inflammation driven by oxidative stress. Several models of bronchial epithelial cells are used to study the molecular mechanisms and the cellular functions altered by cigarette smoke extract (CSE) exposure, and to test the efficacy of molecules with antioxidant properties. This review offers a comprehensive synthesis of human in-vitro and ex-vivo studies published from 2011 to 2021 describing the molecular and cellular mechanisms evoked by CSE exposure in bronchial epithelial cells, the most used experimental models and the mechanisms of action of cellular antioxidants systems as well as natural and synthetic antioxidant compounds.     

Lipid changes in HL-60 cells on differentiation into macrophages by treatment with a phorbol ester

We studied changes in lipid composition of human promyelocytic leukemia cells (HL-60) on differentiation to the macrophage/monocytic lineage by treatment with the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate. Differentiation was accompanied by: (i) a decrease in the level of phospholipids; (ii) a greater amount of triacylglycerols; (iii) an increase in 1-alk-1′-enyl-2-acyl- and 1-alkyl-2-acyl-sn-glycero-3-phosphoethanolamine and a decrease in 1-alkyl-2-acyl-sn-glycero-3-phosphocholine; and (iv) an increase in the level of arachidonic acid in ethanolamine phospholipids. The increased levels of ether-linked lipids and of arachidonic acid in ethanolamine phospholipids are consistent with an enhanced biosynthesis of platelet-activating factor and eicosanoids, which are particularly important in the macrophage function.     

Synthesis of High‐Purity Ti3SiC2 by Microwave Sintering

High‐purity ternary laminated compound Ti₃SiC₂ was successfully synthesized by a microwave heating method in the flowing argon for the first time. The mixtures of titanium, silicon, and graphitic carbon (C_gc) or activated carbon (C_ac) with different molar ratios were used to investigate the reaction mechanisms. It was confirmed that Ti₃SiC₂ with high purity of 98 vol.% was achieved without the aids of Al. The optimum experimental parameters were determined as Ti/Si/C_gc having the molar ratio of 3/2.2/2, first holding at 1480°C for 30 min, and subsequent dwelling at 1300°C for 60 min.     

Redox potentials and binding enhancement of fullerene and fullerene-cyclodextrin systems in water and dimethylsulfoxide

The formal redox potentials of electron transfer reactions of fullerene, methanofullerene, fullerene-cyclodextrin complex and methanofullerene conjugates with cyclodextrins in aqueous and dimethylsulfoxide solutions are reported. These new compounds are surface active and retain the redox activity of C₆₀ even in aqueous medium. Compounds have been characterized by an electrochemical admittance technique, which offers an advantage of separating faradaic and capacitive properties. Observed difference of formal redox potentials of the free fullerene forms and their cyclodextrin-containing compounds were used to determine the binding enhancement. Results are interpreted in terms of inter-molecular host-guest interactions of C₆₀-cyclodextrin conjugates.     

Effects of Cadmium Exposure on Gut Villi in Danio rerio

In aquatic organisms, cadmium exposure occurs from ovum to death and the route of absorption is particularly wide, being represented by skin, gills and gastrointestinal tract, through which contaminated water and/or preys are ingested. It is known that cadmium interferes with the gut; however, less information is available on cadmium effects on an important component of the gut, namely goblet cells, specialized in mucus synthesis. In the present work, we studied the effects of two sublethal cadmium concentrations on the gut mucosa of Danio rerio. Particular attention was paid to changes in the distribution of glycan residues, and in metallothionein expression in intestinal cells. The results show that cadmium interferes with gut mucosa and goblet cells features. The effects are dose- and site-dependent, the anterior gut being more markedly affected than the midgut. Cadmium modifies the presence and/or distribution of glycans in the brush border and cytoplasm of enterocytes and in the goblet cells’ cytoplasm and alters the metallothionein expression and localization. The results suggest a significant interference of cadmium with mucosal efficiency, representing a health risk for the organism in direct contact with contamination and indirectly for the trophic chain.     

Blood Thiol Redox State in Chronic Kidney Disease

Thiols (sulfhydryl groups) are effective antioxidants that can preserve the correct structure of proteins, and can protect cells and tissues from damage induced by oxidative stress. Abnormal levels of thiols have been measured in the blood of patients with moderate-to-severe chronic kidney disease (CKD) compared to healthy subjects, as well as in end-stage renal disease (ESRD) patients on haemodialysis or peritoneal dialysis. The levels of protein thiols (a measure of the endogenous antioxidant capacity inversely related to protein oxidation) and S-thiolated proteins (mixed disulphides of protein thiols and low molecular mass thiols), and the protein thiolation index (the molar ratio of the S-thiolated proteins to free protein thiols in plasma) have been investigated in the plasma or red blood cells of CKD and ESRD patients as possible biomarkers of oxidative stress. This type of minimally invasive analysis provides valuable information on the redox status of the less-easily accessible tissues and organs, and of the whole organism. This review provides an overview of reversible modifications in protein thiols in the setting of CKD and renal replacement therapy. The evidence suggests that protein thiols, S-thiolated proteins, and the protein thiolation index are promising biomarkers of reversible oxidative stress that could be included in the routine monitoring of CKD and ESRD patients.     

Assessment of intradialysis calcium mass balance by a single pool variable‐volume calcium kinetic model

Introduction: A reliable method of intradialysis calcium mass balance quantification is far from been established. We herein investigated the use of a single‐pool variable‐volume Calcium kinetic model to assess calcium mass balance in chronic and stable dialysis patients. Methods: Thirty‐four patients on thrice‐weekly HD were studied during 240 dialysis sessions. All patients were dialyzed with a nominal total calcium concentration of 1.50 mmol/L. The main assumption of the model is that the calcium distribution volume is equal to the extracellular volume during dialysis. This hypothesis is assumed valid if measured and predicted end dialysis plasma water ionized calcium concentrations are equal. A difference between predicted and measured end‐dialysis ionized plasma water calcium concentration is a deviation on our main hypothesis, meaning that a substantial amount of calcium is exchanged between the extracellular volume and a nonmodeled compartment. Findings: The difference between predicted and measured values was 0.02 mmol/L (range ?0.08:0.16 mmol/L). With a mean ionized dialysate calcium concentration of 1.25 mmol/L, calcium mass balance was on average negative (mean ± SD ?0.84 ± 1.33 mmol, range ?5.42:2.75). Predialysis ionized plasma water concentration and total ultrafiltrate were the most important predictors of calcium mass balance. A significant mobilization of calcium from the extracellular pool to a nonmodeled pool was calculated in a group of patients. Discussion: The proposed single pool variable‐volume Calcium kinetic model is adequate for prediction and quantification of intradialysis calcium mass balance, it can evaluate the eventual calcium transfer outside the extracellular pool in clinical practice.     

How important is tryptophan in human health?

Tryptophan (Trp) is an amino acid and an essential component of the human diet. It plays a crucial role in many metabolic functions. Clinicians can use Trp levels in the course of diagnosing various metabolic disorders and the symptoms associated with those diseases. Furthermore, supplementation with this amino acid is considered in the treatment of depression and sleep disorders, mainly due to the Trp relationship with the synthesis of serotonin (5-HT) and melatonin. It is also used in helping to resolve cognitive disorders, anxiety, or neurodegenerative diseases. Reduced secretion of serotonin is associated with autism spectrum disorder, obesity, anorexia and bulimia nervosa, and other diseases presenting peripherals symptoms. The literature strongly suggests that Trp has a significant role in the correct functionality of the brain-gut axis and immunology. This information leads to the consideration of Trp as an essential dietary component due to its role in the serotonin pathway. A reduced availability of Trp in diet and nutraceutical supplementation should be considered with greater concern than one might expect. This paper constitutes a review of the more salient aspects gleaned from the current knowledge base about the role of Trp in diseases, associated nutritional disorders, and food science, in general.