IL-18 level in patients undergoing coronary artery bypass grafting surgery or valve replacement: which link with epicardial fat depot?

Interleukin-18 (IL-18) is a member of the interleukin-1 family of cytokines produced constitutively by different cell types and by adipose tissue. Due to the link between obesity, inflammation and cardiovascular diseases, we aimed to measure IL-18 circulating level in patients undergoing open-heart surgery both for elective coronary artery bypass grafting (CABG) or for valve replacement (VR), and we also evaluated whether epicardial adipose tissue (EAT) depot may be a potential source of IL-18. Circulating IL-18 protein was quantified by enzyme-linked immunosorbent assay. IL-18, IL-18 receptor 1 (IL-18 R1) and IL-18 receptor accessory protein (IL-18-RAP) gene expression in EAT depot were evaluated by one colour microarray platform. EAT thickness was measured by echocardiography. In this study we found that all cardiovascular patients (CABG and VR) have increased circulating IL-18 level compared to healthy control subjects (p < 0.0001), but no statistical significant difference was observed between CABG and VR groups (p = 0.35). A great increase in the gene expression of IL-18 (p < 0.05), IL-18 R1 (p < 0.01) and IL-18 RAP (p < 0.001) was observed in EAT samples obtained from CABG vs VR patients. In conclusion, CABG and VR patients had similar increased level of circulating IL-18 protein, but in EAT depots isolated from CABG gene expression of IL-18, IL-18 R1 and IL-18-RAP resulted higher than in VR patients. Future investigation on local IL-18 protein production, its autocrine-paracrine effect and its correlation with plasmatic IL-18 level could give more information on the relationship between IL-18 and coronary artery disease.

Fifty-kDa hyaluronic acid upregulates some epidermal genes without changing TNF-α expression in reconstituted epidermis.

BACKGROUND: Due to its strong water binding potential, hyaluronic acid (HA) is a well-known active ingredient for cosmetic applications. However, based on its varying molecular size, skin penetration of HA may be limited. Recent studies have demonstrated that low-molecular-weight HA (LMW HA) may show a certain proinflammatory activity. We thus aimed to characterize an LMW-sized HA molecule that combines strong anti-aging abilities with efficient skin penetration but lacks potential proinflammatory effects. METHODS: Total RNA and total protein were isolated from reconstituted human epidermis following incubation with HAs of various molecular weights (20, 50, 130, 300, 800 and 1,500 kDa). Tumor necrosis factor-α expression was determined using quantitative PCR. Genomic and proteomic expression of various junctional proteins was determined using Affymetrix and common Western blotting techniques. RESULTS: LMWHA of approximately 50 kDa did not significantly alter tumor necrosis factor-α expression compared to 20-kDa HA, but revealed significantly higher skin penetration rates than larger sized HA associated with increased expression of genes and proteins known to be involved in tight junction formation and keratinocyte cohesion. CONCLUSION: LMW HA of approximately 50 kDa shows better penetration abilities than larger-sized HA. In addition, LMW HA influences the expression of various genes including those contributing to keratinocyte differentiation and formation of intercellular tight junction complexes without showing proinflammatory activity. These observations contribute to current knowledge on the effects of LMW HA on keratinocyte biology and cutaneous physiology.