Involvement of high cholesterol and oxidative stress in cardiovascular diseases is well studied, as it can be hypothesized that various products originated from lipid peroxidation, such as oxysterols, or affected protein expression might lead to cardiomyocyte damage followed by the pathological modifications. Although oxidation of excessive cholesterol to oxysterols in elevated stress conditions is identified by a number of studies, the role of a high cholesterol diet in regulating fatty acid and oxysterol accumulation, together with scavenger receptor mRNA levels, in the heart remains little investigated. Our study provides a detailed analysis of the changes in fatty acid, oxysterol, and scavenger receptor profiles and its relation with histological alterations in the heart tissue. We evaluated alterations of fatty acid composition, by the GC‐MS method, while 4β‐, 25‐, and 27‐hydroxycholesterol and 7‐ketocholesterol levels by means of LC‐MS/MS in high cholesterol diet‐fed rabbits. Additionally, a number of proteins related to lipid metabolism and scavenger receptor mRNA expressions were evaluated by Western blotting and RT‐PCR. According to our in vivo results, a high cholesterol diet enhances a number of unsaturated fatty acids, oxysterols, and LXRα, in addition to CD36, CD68, CD204, and SR‐F1 expressions while α‐tocopherol supplementation decreases LXRα and SR expressions together with an increase in 27‐hydroxycholesterol and ABCA1 levels. Our results indicated that the high cholesterol diet modulates proteins related to lipid metabolism, which might result in the malfunction of the heart and α‐tocopherol shows its beneficial effects. We believe that this work will lead the generation of different theories in the development of heart diseases.

Aging has been characterized with the accumulation of oxidized proteins, as a consequence of progressive decline in proteostasis capacity. Among others, proteasomal system is an efficient protein turnover complex to avoid aggregation of oxidized proteins. Heat shock protein 70 (HSP70) is another critical player that is involved in some key processes including the correct folding of misfolded proteins and targeting aggregated proteins to the proteasome for rapid degradation. The aim of this study was to determine the role of proteasomal system and heat shock proteins to maintain proteome balance during replicative senescence in mild hyperthermia conditions. Our results demonstrated that HSP40/70 machinery is induced by mild hyperthermia conditions independent from senescence conditions. Since HSP70 is largely responsible for the rapidly inducible cell protection following hyperthermia, the activation of “heat shock response” resulted in the elevation of HSP40/70 expressions as well as the proteasome activity. Interestingly, when HSP70 expression was inhibited, increased proteasomal activation was shown to be responsive to mild hyperthermia. Since HSP70 is involved in various stress-related pathways such as oxidative and endoplasmic reticulum stress, depletion of HSP70 expression may induce proteasomal degradation to maintain proteome balance of the cell. Thus, our data suggests that in mild heat stress conditions, molecular chaperone HSP70 plays an important role to avoid protein oxidation and aggregation; however, activities of proteasomal system are induced when HSP70 expression is depleted.

Over the past century, research on vitamin E has evolved from its initial identification as a fertility factor to the recognition of α-tocopherol (α-TOH) as an essential micronutrient with antioxidant and gene regulatory functions. Despite extensive investigation, controversies persist regarding its precise biological role, clinical efficacy, and classification as a vitamin. This review summarizes scientific milestones in vitamin E (tocochromanol) research. It highlights recent advances in understanding the absorption, metabolism, and molecular mechanisms of vitamin E. The review also outlines unresolved questions and methodological challenges. The focus is on α-TOH and its metabolites, which exhibit biological activities beyond classical antioxidant effects, such as the regulation of inflammation, lipid metabolism, and immune responses. Evidence from genetic, biochemical, and clinical studies supports the essentiality of α-TOH in humans, as demonstrated by ataxia with vitamin E deficiency (AVED). Other tocochromanols and their metabolites exhibit promising biological activities that suggest potential therapeutic applications. However, their physiological relevance must be confirmed. Advances in metabolomic profiling and molecular modeling now allow for a more comprehensive characterization of vitamin E metabolism and function. Understanding the molecular pathways and biological roles of vitamin E and its derivatives is crucial for refining its definition, establishing evidence-based dietary recommendations, and evaluating its potential in disease prevention and therapy.

Naturally occurring vitamin E is a lipophilic plant-derived molecule corresponding to the 2R forms of alpha-tocopherol. A series of natural analogs or tocochromanols are present in nature, including β-, γ- and δ-tocopherol (βT, γT, δT), the corresponding tocotrienols (αTE, βTE, γTE, δTE) and tocomonoenols. Differences between these analogs as lipophilic antioxidants and modulators of molecular processes suggest specific therapeutic properties against various disorders associated with acute and chronic inflammation. However, hepatic metabolism of these compounds via cytochrome P450-initiated side chain ω-oxidation involves the production of long-chain metabolites (LCMs) followed by intermediate (ICMs) and short-chain metabolites (SCMs), respectively. Despite the initial studies indicating these metabolites as catabolic-end products, recent findings identify their importance in providing biological functions. In this scope, LCMs, especially 13'-carboxychromanols (13'-COOHs), have been reported to hold stronger anti-inflammatory capacity than their unmetabolized precursors due to their ability to inhibit 5-lipoxygenase and cyclooxygenase-catalyzed eicosanoid formation, as well as their modulation of the pro-inflammatory transcriptional protein nuclear factor κB (NF-κB). Also, these LCMs have been reported to enhance detoxification and lipid metabolism pathways associated with cellular inflammation by modulating the nuclear receptors peroxisome proliferator-activated receptor-γ (PPARγ) and pregnane x receptor (PXR). These properties of LCMs will be described in this narrative review article focusing on recent information regarding their bioavailability, anti-inflammatory effects, and mechanisms of action in acute and chronic inflammatory disorders.