Age-associated chronic inflammation is characterized by unresolved and uncontrolled inflammation with multivariable low-grade, chronic and systemic responses that exacerbate the aging process and age-related chronic diseases. Currently, there are two major hypotheses related to the involvement of chronic inflammation in the aging process: molecular inflammation of aging and inflammaging. However, neither of these hypotheses satisfactorily addresses age-related chronic inflammation, considering the recent advances that have been made in inflammation research. A more comprehensive view of age-related inflammation, that has a scope beyond the conventional view, is therefore required. In this review, we discuss newly emerging data on multi-phase inflammatory networks and proinflammatory pathways as they relate to aging. We describe the age-related upregulation of nuclear factor (NF)-κB signaling, cytokines/chemokines, endoplasmic reticulum (ER) stress, inflammasome, and lipid accumulation. The later sections of this review present our expanded view of age-related senescent inflammation, a process we term “senoinflammation”, that we propose here as a novel concept. As described in the discussion, senoinflammation provides a schema highlighting the important and ever-increasing roles of proinflammatory senescence-associated secretome, inflammasome, ER stress, TLRs, and microRNAs, which support the senoinflammation concept. It is hoped that this new concept of senoinflammation opens wider and deeper avenues for basic inflammation research and provides new insights into the anti-inflammatory therapeutic strategies targeting the multiple proinflammatory pathways and mediators and mediators that underlie the pathophysiological aging process.
The intestine plays an essential role in integrating immunity and nutrient digestion and absorption. Adjacent intestinal epithelia form tight junctions (TJs) that are essential to the function of the physical intestinal barrier, regulating the paracellular movement of various substances including ions, solutes, and water across the intestinal epithelium. Studies have shown that TJ dysfunction is highly associated with metabolic and inflammatory diseases. Thus, molecular and nutritional factors that improve TJ activity have gained attention in the pharmaceutical and medicinal fields. This review focuses on the association between TJ and diverse pathological conditions, as well as various molecular and nutritional interventions designed to boost TJ integrity.
Enzymatic browning because of polyphenol oxidases (PPOs) contributes to the color quality of fruit and vegetable (FV) products. Physical and chemical methods have been developed to inhibit the activity of PPOs, and several synthetic chemical compounds are commonly being used as PPO inhibitors in FV products. Recently, there has been an emphasis on consumer-oriented innovations in the food industry. Consumers tend to urge the use of natural and environment-friendly PPO inhibitors. The purpose of this review is to summarize the mechanisms underlying the anti-browning action of chemical PPO inhibitors and current trends in the research on these inhibitors. Based on their mechanisms of action, chemical inhibitors can be categorized as antioxidants, reducing agents, chelating agents, acidulants, and/or mixed-type PPO inhibitors. Here, we focused on the food ingredients, dietary components, food by-products, and waste associated with anti-browning activity.
The absorptive cells of the small intestine, enterocytes, are not generally thought of as a cell type that stores triacylglycerols (TGs) in cytoplasmic lipid droplets (LDs). We revisit TG metabolism in enterocytes by ex vivo and in vivo coherent anti-Stokes Raman scattering (CARS) imaging of small intestine of mice during dietary fat absorption (DFA). We directly visualized the presence of LDs in enterocytes. We determined lipid amount and quantified LD number and size as a function of intestinal location and time post-lipid challenge via gavage feeding. The LDs were confirmed to be primarily TG by biochemical analysis. Combined CARS and fluorescence imaging indicated that the large LDs were located in the cytoplasm, associated with the tail-interacting protein of 47 kDa. Furthermore, in vivo CARS imaging showed real-time variation in the amount of TG stored in LDs through the process of DFA. Our results highlight a dynamic, cytoplasmic TG pool in enterocytes that may play previously unexpected roles in processes, such as regulating postprandial blood TG concentrations. With obesity and cardiovascular disease being worldwide health issues, the impetus of understanding the parameters that govern energy intake and blood lipid concentration has emerged. Blood lipid concentration and a major portion of energy intake are regulated through the highly efficient process of dietary fat absorption (DFA) by the small intestine. Greater than 95% of dietary fat consumed is absorbed whether a low-or high-fat diet is consumed (1), as evidenced by the small amount of fat that is excreted in feces. In the small intestine lumen, dietary fat in the form of triacylglycerol (TG) is hydrolyzed to generate FFAs and monoacylglycerols (MGs) by pancreatic lipase. These products are then emulsified with the help of phospholipids and bile acids present in bile to form micelles. FFAs and MGs are then taken up by the absorptive cells of the small intestine, enterocytes, where they are resynthesized into TGs and incorporated into the core of chylomicrons (CMs), which are secreted via the lymphatic system into the circulation (2, 3).Most current models of the synthesis of CMs show the resynthesized TG in this process entering the lumen of the endoplasmic reticulum (ER) where the assembly of CMs begins and do not highlight the potential for the resynthesized TG to enter a cytoplasmic TG storage pool unless there is a defect in CM synthesis or secretion (1,(3)(4)(5)(6)(7)(8). In fact, wild-type mice fed a high-fat diet, or challenged with an oil bolus by oral gavage, are commonly reported as having no lipid droplet (LD) accumulation in enterocytes (9-11). Nevertheless, both indirect and direct evidence exists supporting the presence of a cytoplasmic storage pool in enterocytes. In humans, sequential meal tests demonstrated that CMs secreted after a second meal carried TG ingested in the first meal (12, 13). In rats, TG is synthesized within 30 s after an intraduodenal fat infusion (14); however, the secretion of TG into the lymph does n...
The specific role of dietary fat in breast cancer progression is unclear, although a low-fat diet was associated with decreased recurrence of estrogen receptor alpha negative (ER(-)) breast cancer. ER(-) basal-like MDA-MB-231 and MDA-MB-436 breast cancer cell lines contained a greater number of cytoplasmic lipid droplets compared to luminal ER(+) MCF-7 cells. Therefore, we studied lipid storage functions in these cells. Both triacylglycerol and cholesteryl ester (CE) concentrations were higher in the ER(-) cells, but the ability to synthesize CE distinguished the two types of breast cancer cells. Higher baseline, oleic acid- and LDL-stimulated CE concentrations were found in ER(-) compared to ER(+) cells. The differences corresponded to greater mRNA and protein levels of acyl-CoA:cholesterol acyltransferase 1 (ACAT1), higher ACAT activity, higher caveolin-1 protein levels, greater LDL uptake, and lower de novo cholesterol synthesis in ER(-) cells. Human LDL stimulated proliferation of ER(-) MDA-MB-231 cells, but had little effect on proliferation of ER(+) MCF-7 cells. The functional significance of these findings was demonstrated by the observation that the ACAT inhibitor CP-113,818 reduced proliferation of breast cancer cells, and specifically reduced LDL-induced proliferation of ER(-) cells. Taken together, our studies show that a greater ability to take up, store and utilize exogenous cholesterol confers a proliferative advantage to basal-like ER(-) breast cancer cells. Differences in lipid uptake and storage capability may at least partially explain the differential effect of a low-fat diet on human breast cancer recurrence.
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