Effects of sirtuin 1 activation on nicotine and lipopolysaccharide-induced cytotoxicity and inflammatory cytokine production in human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Although sirtuin 1 (SIRT1) over-expression and resveratrol exert anti-inflammatory and proinflammatory effects, their effects and the mechanism of action on human gingival fibroblast (HGF)-mediated inflammation are unknown. The aim of this study was to demonstrate the effects of activating SIRT1 using resveratrol and recombinant adenovirus encoding SIRT1 (Ad-SIRT1) on the expression of proinflammatory cytokines and to elucidate its mechanism of action of lipopolysaccharide (LPS) and nicotine stimulated-HGF. MATERIAL AND METHODS: Cytotoxicity and the production of reactive oxygen species (ROS) were measured using the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. The amount of prostaglandin E2 (PGE2 ) released into the culture medium was measured by radioimmunoassay. mRNA and protein levels were analyzed using RT-PCR and western blotting, respectively. RESULTS: Nicotine and LPS up-regulated the expression of SIRT1 mRNA and SIRT1 protein in a time- and concentration-dependent manner. Resveratrol and Ad-SIRT1 decreased LPS and nicotine-induced cytotoxicity, ROS and PGE2 production, and expression of cyclooxygenase-2 in HGFs. Resveratrol and Ad-SIRT1 inhibited nicotine and LPS-mediated protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), p38, ERK, JNK, MAPK and nuclear factor-kappa B (NF-κB) activation. CONCLUSION: This study is the first to show that the anti-inflammatory and cytoprotective effects of SIRT1 activation in HGFs occur through the PKC, PI3K, MAPK and NF-κB pathways.

The effects of the p-nitrophenyl esters of the even-numbered fatty acids from caproic (C6) to stearic (C18) on the main phase transition of dimyristoylphosphatidylcholine.

Differential scanning calorimetry (DSC) is employed in a study of the effects of the p-nitrophenyl esters of the even numbered fatty acids from C6 (caproic acid) to C18 (stearic acid) on the main phase transition of multilamellar suspensions of dimyristoylphosphatidylcholine (DMPC). Mole fractions in the range of 0.02-0.12 were used. Within this concentration range the observed transitions could be well fit on the basis of a model assuming ideal behavior of the esters in both the gel and liquid crystal phases of the lipid, and independently additive van't Hoff and impurity broadening. As expected on the basis of this model, the transition temperatures decreased linearly with increasing ester concentration and the transition enthalpies were independent of ester concentration. Significant differences between the effects of the various esters were observed, but these did not change with changing ester chain length in any regular fashion.

Silicone gel sheets relieve pain and pruritus with clinical improvement of keloid: possible target of mast cells.

Silicone gel sheet treatment is widely used to treat hypertrophic scars and keloids since it is easily applied and prevents scar pain and itching. We used Cica-Care silicone gel sheets in the conservative treatment of six patients for 24 weeks and recorded pain, itching, redness, and scar elevation every 4 weeks. We also investigated the number of mast cells and Fas antigen expression in the lesional skin (one patient) before and after treatment. The pain and itching clearly decreased after 4 weeks of the silicone gel sheeting and disappeared after 12 weeks. Twelve weeks were required for a reduction in scar redness and elevation. After 24 weeks, a decrease in the number of mast cells and the enhanced expression of Fas antigen by lesional fibroblasts were observed. Thus, silicone gel sheeting is effective and safe, especially with more severe symptoms of pain and itching possibly induced by mediators derived from increased mast cells.