Mobility of Water Molecules in the Stratum Corneum: Effects of Age and Chronic Exposure to the Environment

enhanced antimicrobial activity against P. acnes and inhibited the expression of proinflammatory cytokines, such as IL-8 and tumor necrosis factor-a. Our data showed that the T-zone had a low incidence of inflammatory acne lesions compare with U-zone. These data support the previous findings that hBD-2 levels indicate the presence of antiinflammatory lipids, which inhibit inflammation, therefore, only a few clinically inflammatory lesions occur (Georgel et al., 2005; Zouboulis et al., 2010). Previous studies demonstrated that FFAs enhance the innate antibacterial defenses of the skin by inducing the expression of AMP (Lee et al., 2008; Nakatsuji et al., 2010). Our findings also showed that considerable FFAs in the high-sebum-secreting area (T-zone) induce more abundant hBD-2 expression, and enhanced antimicrobial activity against P. acnes and inhibited the expression of proinflammatory cytokines. However, it needs to further evaluation for the expression of other AMP in each area, because other AMP may also have a role in regional difference of inflammatory acne lesions (Lee et al., 2008, 2009). There was a previous study that hBD-2 strikingly killed P. acnes at concentrations higher than 10 mM (Nakatsuji et al., 2010). Although we showed which amount of hBD-2 in sebocytes from T-zones able to influence the growth of P. acnes in vitro, it needs further in vivo study especially in acne lesions. In conclusion, we suggest that increased hBD-2 in the T-zone prevents the progress of comedones to papulopustular lesions via either an upregulation of antiinflammatory sebaceous lipid synthesis and/or an inhibitory activity of P. acnes proliferation. These data suggest a functional link between topographical variation of inflammatory acne lesions and innate immunity in acne pathogenesis. Further studies of the relationship between hBD-2 expression and P. acnes in acne lesion are warranted to gain the confirmation of the effects of hBD-2 on regional difference of inflammatory acne lesions.