BLOOD FLOW IN FACIAL SKIN 509 may be induced by a reduction in blood flow. The order of the blood flow parameters differed slightly among the morphological parameters, being Finter_ L Fmi n Fres• Fpost_ L Fma x for sWp Finter_ L Frest Fmi n Fpost_ L Fma x for sWt and Frost Finter_ L Finax Fpost_ L Finin for sWa. Finter_L, which is the mean blood flow during cooling, showed high correlations with all morphological parameters. Fin•_ L was followed by F•s• , which is the mean resting blood flow. This suggest that changes in mean blood flow are more important than are changes in maximum or minimum blood flows, which are transient states, for morphological changes at the skin surface. We examined the extent of the effect of cheek blood flow at peripheral areas of the cheek and found the highest correlation at the corner of the mouth, which is closest to the cheek. However, Fr•s• and Fma x showed the highest correlations at this site. Fm• x is the maximum blood flow between the end of the cooling period and the end of the mea- surement, and the effect of changes in skin blood flow may differ among various peripheral sites of the cheek. On the other hand, concerning the relationship between blood flow parameters and age in the skin of elderly female subjects, similar results were obtained in the forehead and in the cheek. In this study, no significant correlation was observed between blood flow parameters and age in the cheek skin, and age-associated decreases were observed in blood flow parameter Fma x (p 0.05) only in the forehead skin. While marked age- associated decreases were observed in blood flow during cooling at 10øC in the cheek, the effect of aging on blood flow has been reported to be small in the forehead (15). Therefore, blood flow parameters in the forehead and in the cheek are considered to show different changes between a subject group consisting of all age levels and a group consisting of only elderly individuals. Concerning the relationship between the param- eters of surface morphology and age, correlation coefficients were smaller in elderly subjects in all areas other than the cheek compared with those for all ages combined (10). In contrast, in the cheek, a high correlation was observed in the group aged 60 years and above (sWp: r = -0.385 in the elderly group r = -0.433 in all subjects). This suggests that the surface of the cheek skin becomes irregular for some reason as one becomes older. Kligman et al. (24) classified the criss-cross patterns that develop in cheek skin, a sun-exposed area, in the elderly as glyphic wrinkles. The irregularities that we measured in this study are considered to be similar to that type of wrinkle. Kligman et al. also classified wrinkles that develop at the corner of the eye and on the forehead as linear grooves, which are chronically exposed to ultraviolet rays. They reported that wrinkles at sites chronically exposed to ultraviolet rays had a different morphology. These results suggest that a reduction in blood flow is one putative cause of local irregularities observed in the cheek skin (glyphic wrinkles) of the elderly. It has been reported that an age-related tendency to decreased blood flow occurs in facial skin (15). The putative cause of such an observation was considered to be hyperplasia in the capillary walls due to delays in the healing of blood vessel injuries caused by UV irradiation (25,26). On the other hand, it is well known that chronic exposure of the skin to UV leads to the appearance of wrinkles (27-29). Therefore, in facial skin exposed to UV, not only do wrinkles form but also the blood flow tends to decrease. It is conceivable that the cheek is a more exposed site than is the forehead. Hence, it seems that there is a higher correlation between morphology and blood flow in the cheek compared with other facial sites. Therefore, daily skin care to improve cutaneous blood flow should be important in preventing cheek skin aging.

510 JOURNAL OF COSMETIC SCIENCE Previously, Imokawa and Takema (30) quantified fine wrinkles at the outer corner of the eye by image analysis using replicas obtained from females in their 30s, and they measured the mean annual water content of the stratum corneum and TEWL. They reported that the degree of fine wrinkles (morphology of the skin surface) was closely related to decreases in the water content of the stratum comeurn but not to TEWL. Takema eta/, also reported that skin elasticity decreases with aging in the outer corner of the eye and in the cheek and that it correlates closely with increases in the wrinkle score, particularly at the outer corner of the eye (21,22). For this reason, the development of preparations to prevent and treat wrinkles at the outer corner of the eye, especially by increasing the water content of the stratum corneum and improving skin elasticity, are progressing (31,32). However, according to our results on the relationship between the water content of the stratum corneum and skin elasticity, no correlation was observed between the parameters of blood flow and the parameters of the three-dimensional morphology. The lack of correlation between these physiological parameters of the skin may be explained by the facts that the subjects examined in this study were elderly individuals aged 60 years or more, that the number of subjects was only 40, and/or that the target wrinkles were glyphic wrinkles, which are a special type of wrinkle, rather than wrinkles at the outer corner of the eye. Further, a positive correlation has been suggested between blood flow and percutaneous water evaporation, in a report concern- ing inflammation (16). In this study, TEWL was not measured, and further evaluation of this property and its possible relationships with these physiologic parameters of the skin is anticipated. From these results, we suggest that reductions in blood flow are one putative cause of local irregularities, that is, glyphic wrinkles, in cheek skin. REFERENCES (1) P. G. Agache, J. Mignot, and S. Makki, "Microtopography of the Skin and Aging," in Cutaneous Aging, A.M. Kligman and Y. Takase, Eds. (University of Tokyo Press, Tokyo, 1988), pp. 475-490. (2) G. L. Grove and M.J. Grove, "Objective Methods for Assessing Skin Surface Topography Noninva- sively," in Cutaneous Investigation in Health and Disease, J. L. Leveque, Ed. (Marcel Dekker, New York, Basel, 1980), pp. 1-32. (3) J. L. Leveque, and P. Cotcuff, "The Surface of the Skin," in Noninvasive Methods for the QuantijS'cation of Skin Functions, P.J. Frosch and A.M. Kligman, Eds. (Springer-Verlag, Berlin, 1993), pp. 223-240. (4) P. Corcuff, J. L. Leveque, G. L. Grove, and A.M. Kligman, The impact of aging on the microrelief of peri-orbital and leg skin, J. Soc Cosmet. Chem., 82, 145-152 (1987). (5) S. Hayashi, T. Matsuki, K. Matsue, S. Arai, Y. Fukuda, and T. Yoneya, Changes of facial wrinkles by aging and application of cosmetics, J. Sot'. Cosmet. Chem. Jpn., 27, 355-373 (1993). (6) S. Hayashi, K. Mimura, and Y. Nishijima, Changes in surface configuration of skin caused by aging and application of cosmetics, Int. J. Cosmet. Sci., 11, 67-85 (1989). (7) P. Corcuff, J. de Rigal, J. L. Leveque, S. Makki, and P. Agache, Skin relief and aging, J. Soc. Cosmet. Chem,, 34, 177-190 (1983). (8) T. Ishida, N. Kashibuchi, K. Morita, and S. Tuasa, Measurement of skin roughness by computerized surface tracing and applications in cosmetic efficacy substantiation, Cosmet, Toi/etr., 94, 39•i7 (1979). (9) S. Nicholls, C. S. King, and R. Marks, Short term effects of emollients and a bath oil on the stratum corneum, J. Soc Cosmet. Chem., 29, 617-624 (1978). (10) Y. Takema, K. Tsukahara, T. Fujimura, and M. Hattori, Age-related changes in the three-dimensional morphological structure of human facial skin, Skin Res. Tech., 3, 95-100 (1997). (11) R. I. Murahata, D. M. Crowe, and J. R. Roheim, Evaluation of hydration state and surface defects in the stratum comeurn: Comparison of computer analysis and visual appraisal of positive replicas of human skin,J. Soc. Cosmet. Chem., 35, 327-338 (1984). (12) M. Mochizuka, H. Inoue, M. Shaku, H. Koiso, S. Nozawa, N. Kashibuchi, M. Makino, H. Nakano,