Evaluation of psychological stress in confined environments using salivary, skin, and facial image parameters.

Detecting the influence of psychological stress is particularly important in prolonged space missions. In this study, we determined potential markers of psychological stress in a confined environment. We examined 23 Japanese subjects staying for 2 weeks in a confined facility at Tsukuba Space Center, measuring salivary, skin, and facial image parameters. Saliva was collected at four points in a single day to detect diurnal variation. Increases in salivary cortisol were detected after waking up on the 4th and 11th days, and at 15:30 on the 1st and in the second half of the stay. Transepidermal water loss (TEWL) and sebum content of the skin were higher compared with outside the facility on the 4th and 1st days respectively. Increased IL-1ß in the stripped stratum corneum was observed on the 14th day, and 7 days after leaving. Differences in facial expression symmetry at the time of facial expression changes were observed on 11th and 14th days. Thus, we detected a transition of psychological stress using salivary cortisol profiles and skin physiological parameters. The results also suggested that IL-1ß in the stripped stratum corneum and facial expression symmetry are possible novel markers for conveniently detecting psychological stress.

Grapefruit oil attenuates adipogenesis in cultured subcutaneous adipocytes.

We investigated the effects of different essential oils on adipogenesis in rat subcutaneous adipocytes. Subcutaneous preadipocytes were cultured in Dulbecco's Modified Eagle Medium (DMEM) containing insulin, transferrin, fibroblast growth factor, dexamethasone, indomethacin, fetal bovine serum, and an essential oil at 37 degrees C in 5% CO2 to induce their differentiation. After 7 days, the number of viable cells and the amount of triglycerides accumulated in the cells were determined. Differentiation markers such as the enzymatic activity of glycerol-3-phosphate dehydrogenase (GPDH) and the expression of GPDH and peroxisome proliferator-activated receptor gamma (PPAR gamma) genes were also measured, as well as the intracellular Ca2+ levels. We found that grapefruit oil inhibited the accumulation of triglycerides in a dose-dependent manner at concentrations of 50 to 400 microg/mL. Furthermore, it suppressed the expression of GPDH and caused a 70% decrease in the enzymatic activity of GPDH at a concentration of 50 microg/mL. Grapefruit oil also caused a nearly 2-fold increase in the intracellular concentration of Ca2+ and suppressed the expression of PPAR gamma genes. Our results demonstrate that grapefruit oil efficiently inhibits adipogenesis in cultured subcutaneous preadipocytes and adipocytes.

Effects of fragrance inhalation on sympathetic activity in normal adults.

We investigated the effects of fragrance inhalation on sympathetic activity in normal adult subjects using both power spectral analysis of blood pressure fluctuations and measurement of plasma catecholamine levels. Fragrance inhalation of essential oils, such as pepper oil, estragon oil, fennel oil or grapefruit oil, resulted in 1.5- to 2.5-fold increase in relative sympathetic activity, representing low frequency amplitude of systolic blood pressure (SBP-LF amplitude), compared with inhalation of an odorless solvent, triethyl citrate (P<0.05, each). In contrast, fragrance inhalation of rose oil or patchouli oil caused a 40% decrease in relative sympathetic activity (P<0.01, each). Fragrance inhalation of pepper oil induced a 1.7-fold increase in plasma adrenaline concentration compared with the resting state (P = 0.06), while fragrance inhalation of rose oil caused a 30% decrease in adrenaline concentration (P<0.01). Our results indicate that fragrance inhalation of essential oils may modulate sympathetic activity in normal adults.