Keiichi Sugata

Ethnic differences in the structural properties of facial skin

BACKGROUND Conspicuous facial pores are one type of serious aesthetic defects for many women. However, the mechanism(s) that underlie the conspicuousness of facial pores remains unclear. We previously characterized the epidermal architecture around facial pores that correlated with the appearance of those pores. OBJECTIVES A survey was carried out to elucidate ethnic-dependent differences in facial pore size and in epidermal architecture. METHODS The subjects included 80 healthy women (aged 30-39: Caucasians, Asians, Hispanics and African Americans) living in Dallas in the USA. First, surface replicas were collected to compare pore sizes of cheek skin. Second, horizontal cross-sectioned images from cheek skin were obtained non-invasively from the same subjects using in vivo confocal laser scanning microscopy (CLSM) and the severity of impairment of epidermal architecture around facial pores was determined. Finally, to compare racial differences in the architecture of the interfollicular epidermis of facial cheek skin, horizontal cross-sectioned images were obtained and the numbers of dermal papillae were counted. RESULTS Asians had the smallest pore areas compared with other racial groups. Regarding the epidermal architecture around facial pores, all ethnic groups observed in this study had similar morphological features and African Americans showed substantially more severe impairment of architecture around facial pores than any other racial group. In addition, significant differences were observed in the architecture of the interfollicular epidermis between ethnic groups. CONCLUSIONS These results suggest that facial pore size, the epidermal architecture around facial pores and the architecture of the interfollicular epidermis differ between ethnic groups. This might affect the appearance of facial pores.

In vivo measurement of human dermis by 1064 nm-excited fiber Raman spectroscopy

Background/aims: Although chemical information on the dermis in vivo is highly important in skin research, an efficient method for gathering this information is yet to be developed. Here, we demonstrate that newly developed near‐infrared (1064 nm) excited Raman spectroscopy is a powerful method for chemical analysis of human skin in vivo.

Confocal laser microscopic imaging of conspicuous facial pores in vivo: relation between the appearance and the internal structure of skin.

Background/purpose: Conspicuous facial pores are one of the more serious esthetic defects of most concern to women. Previous microscopic observations of the skin surface around conspicuous pores have discovered large hollows and uneven skin tone. In this study, the observation area was extended from the skin surface to deeper skin to find the characteristic features of conspicuous pores in a wider spectrum.

Evaluation of photoaging in facial skin by multiphoton laser scanning microscopy.

Background/purpose: It has been reported that autofluorescence (AF) and second harmonic generation (SHG) generated in the upper dermis are related with skin photoaging. In this study, we assessed the photoaging of facial skin exposed to daily sunlight using in vivo multiphoton laser microscopy to measure AF and SHG.

Changes of human skin in subepidermal wound healing process

Background/purpose: The wound healing process involves unexplained mechanisms. An aberration in this process is known to cause dermal disorders such as keloid or hypertrophic scars, but the mechanism by which these scars are formed remains to be elucidated. Here we examined the usefulness of a non‐invasive optical imaging device to clarify mechanisms of wound healing and of scar formation.

Developmental Changes in Neonatal and Infant Skin Structures During the First 6 Months: In Vivo Observation

Developmental changes of structures in neonatal and infant skin have not been well characterized. The purpose of this study was to clarify changes in skin structures during neonatal and infant growth in vivo.

Imaging of melanin distribution using multiphoton autofluorescence decay curves.

Background/purpose: Multiphoton fluorescence lifetime imaging (FLIM) is a technique that produces an image based on differences in the decay rate of fluorescence from a sample. Based on this method, the DermaInspect was developed to observe human skin components non‐invasively. In this study, we used the DermaInspect to study melanin in skin.

Roughness analysis of the skin as a secondary evaluation criterion in addition to visual scoring is sufficient to evaluate ethnic differences in wrinkles

Synopsis

Evaluation of unique elastic aggregates (elastic globes) in normal facial skin by multiphoton laser scanning tomography

BackgroundThere is no reliable marker to estimate the degree of skin aging in vivo. It now has become possible to quantitatively determine the dermal characteristics of the extracellular matrix (ECM) in vivo using multiphoton laser tomography (MLT).MethodsFifty-seven healthy Japanese female volunteers, aged from 20 to 60 years old, were examined using multiphoton depth-resolved measurements of autofluorescence (AF) and second harmonic generation (SHG) at three sites on their right cheek. Paraffin-embedded skin specimens obtained from the faces of 12 normal individuals aged 38-68 years old were stained with Elastica van Gieson (EVG).ResultsWe found unique elastic aggregates at a 20µm depth from the dermo-epidermal junction (DEJ) in vivo which increased in size with aging of subjects from 20 to 60 years old. SHG fibers seemed to surround those elastic aggregates. Histological examination of specimens from normal individuals stained with EVG confirmed the occurrence of elastic aggregates with varied sizes just beneath the epidermis or hair follicles.ConclusionsThe elastic aggregates are morphologically similar to previously described ‘elastic globes’ and can serve as a marker of the early stage of photoaging. MLT will contribute to determine age-related dermal changes using a non-invasive technique.

Changes in hydration of the stratum corneum are the most suitable indicator to evaluate the irritation of surfactants on the skin

Irritancy levels of surfactants on human skin have not been clarified completely. The relationships between skin damage and changes of skin properties caused by various surfactants were investigated using non‐invasive measurements.