Racial differences in skin pathophysiology

Suppression of UVB-Induced MMP-1 Expression in Human Skin Fibroblasts Using Lysate of Lactobacillus iners Derived from Korean Women's Skin in Their Twenties

The process of skin aging is intricate, involving intrinsic aging, influenced by internal factors, and extrinsic aging, mainly caused by exposure to UV radiation, resulting in photoaging. Photoaging manifests as skin issues such as wrinkles and discoloration. The skin microbiome, a diverse community of microorganisms on the skin's surface, plays a crucial role in skin protection and can be affected by factors like humidity and pH. Probiotics, beneficial microorganisms, have been investigated for their potential to enhance skin health by regulating the skin microbiome. This can be accomplished through oral probiotics, impacting the gut-skin axis, or topical applications introducing live bacteria to the skin. Probiotics mitigate oxidative stress, suppress inflammation, and maintain the skin's extracellular matrix, ultimately averting skin aging. However, research on probiotics derived from human skin is limited, and there is no established product for preventing photoaging. The mechanism by which probiotics shield the skin microbiome and skin layers from UV radiation remains unclear. Recently, researchers have discovered Lactobacillus in the skin, with reports indicating a decrease in this microorganism with age. In a recent study, scientists isolated Lactobacillus iners KOLBM20 from the skin of individuals in their twenties and confirmed its effectiveness. A comparative analysis of genetic sequences revealed that strain KOLBM20 belongs to the Lactobacillus genus and closely relates to L. iners DSM13335(T) with a 99.20% similarity. Importantly, Lactobacillus iners KOLBM20 displayed anti-wrinkle properties by inhibiting MMP-1. This investigation demonstrated the inhibitory effect of KOLBM20 strain lysate on MMP-1 expression. Moreover, the data suggest that KOLBM20 strain lysate may prevent UVB-induced MMP-1 expression by inhibiting the activation of the ERK, JNK, and p38 signaling pathways induced by UVB. Consequently, KOLBM20 strain lysate holds promise as a potential therapeutic agent for preventing and treating skin photoaging.

Long-term Safety and Effectiveness of Hyaluronic Acid Fillers Correcting Nasolabial Folds in Chinese Patients

Background

Soft-tissue fillers, specifically hyaluronic acid fillers, can reduce many signs of aging by treating the associated loss of subcutaneous fat and midfacial contour deficiencies. The objective of this study was to investigate whether the effectiveness and safety of Belotero Volume Lidocaine (BVL) compared with Restylane (RES, control) is noninferior in the treatment of severe nasolabial folds (NLFs) in Chinese patients.

Methods

This was a prospective, randomized, controlled, split-face clinical study. Overall, 220 Chinese patients of both sexes with symmetrical NLFs of severe intensity (grade 4) on the Wrinkle Severity Rating Scale (WSRS) were treated with both fillers. Treatment outcomes were assessed by the WSRS, and other scales, at multiple time points up to 18 months postinjection. The co-primary effectiveness outcomes were based on the blinded evaluator ratings of NLFs according to the WSRS scale after 6 and 12 months. Adverse events were assessed during the whole study and patients' pain sensation at three time points after injection.

Results

Noninferiority of BVL versus control based on the WSRS was demonstrated at month 6 and month 12. Response rates were slightly higher for BVL than control at all time points, and BVL had a sustained effect until month 18. Pain sensation scores were significantly lower for BVL compared with control. The incidence rates of treatment-related AEs were low and very similar for both treatments.

Conclusions

This study demonstrates that BVL is a safe, long-lasting, and effective treatment to correct severe NLFs in Chinese patients while being noninferior to the control device.

Clinical outcomes of chemotherapy in cancer patients with different ethnicities

BACKGROUND

Choosing the most effective chemotherapeutic agent with safest side effect profile is a common challenge in cancer treatment. Although there are standardized chemotherapy protocols in place, protocol changes made after extensive clinical trials demonstrate significant improvement in the efficacy and tolerability of certain drugs. The pharmacokinetics, pharmacodynamics, and tolerance of anti-cancer medications are all highly individualized. A driving force behind these differences lies within a person's genetic makeup.

RECENT FINDINGS

Pharmacogenomics, the study of how an individual's genes impact the processing and action of a drug, can optimize drug responsiveness and reduce toxicities by creating a customized medication regimen. However, these differences are rarely considered in the initial determination of standardized chemotherapeutic protocols and treatment algorithms. Because pharmacoethnicity is influenced by both genetic and nongenetic variables, clinical data highlighting disparities in the frequency of polymorphisms between different ethnicities is steadily growing.  Recent data suggests that ethnic variations in the expression of allelic variants may result in different pharmacokinetic properties of the anti-cancer medication. In this article, the clinical outcomes of various chemotherapy classes in patients of different ethnicities were reviewed.

CONCLUSION

Genetic and nongenetic variables contribute to the interindividual variability in response to chemotherapeutic drugs. Considering pharmacoethnicity in the initial determination of standard chemotherapeutic protocols and treatment algorithms can lead to better clinical outcomes of patients of different ethnicities.

Influence of Ethnicities and Skin Color Variations in Different Populations: A Review

BACKGROUND

In the world scientific tradition, skin color is the primary physical characteristic used to divide humans into groups. Human skin has a wide range of tones and colors, which can be seen in a wide range of demographic populations. Many factors influence the color of people's skin, but the pigment melanin is by far the most important. Melanin is produced by cells called melanocytes in the skin and is the primary determinant of skin color in people with darker skin. Indeed, >150 genes have now been identified as having a direct or indirect effect on skin color. Vitamin D has recently been discovered to regulate cellular proliferation and differentiation in a variety of tissues, including the skin. The mechanisms through which the active vitamin D metabolite 1,25 dihydroxyvitamin D3 (or calcitriol) affects keratinocyte development are numerous and overlap with the mechanisms by which calcium influences keratinocyte differentiation. Ultraviolet (UV) is the most major modifiable risk factor for skin cancer and many other environmental-influenced skin disorders when it is abundant in the environment. Although the UV component of sunlight is known to cause skin damage, few researches have looked at the impact of non-UV solar radiation on skin physiology in terms of inflammation, and there is less information on the role of visible light in pigmentation.

SUMMARY

The quantity and quality of melanin are regulating by the expression of genes. The enzyme tyrosinase is primarily responsible for the genetic mechanism that controls human skin color. Genetics determines constitutive skin color, which is reinforced by facultative melanogenesis and tanning reactions. High quantities of melanin and melanogenic substances are typically accepted in darker skin to protect against UV radiation-induced molecular damage. Previous research has proposed that skin color variation is caused by a dynamic genetic mechanism, contributing to our understanding of how population demographic history and natural selection shape human genetic and phenotypic diversity. However, the most significant ethnic skin color difference is determined by melanin content. This current review aimed to assess the influence of skin color variations in skin structure and functions as well as difference in dermatological disease patterns. Also, this article reviewed several cases of skin color adaptation in different populations. Key Messages: Skin color impacts the composition and activity. Therefore, the contrast of dermatological ailments between distinct race-related categories is remarkable. Skin color adaptation is a challenging procedure. Refinement of skin color is an age-old craving of humans with ever-evolving drifts.

Differences between perceived age and chronological age in women: A multi-ethnic and multi-centre study

Objective

Accuracy in assessing age from facial cues is important in social perception given reports of strong negative correlations between perceived age and assessments of health and attractiveness. In a multi‐ethnic and multi‐centre study, we previously documented similar patterns of female facial age assessments across ethnicities, influenced by gender and ethnicity of assessors.

Methods

Here we extend these findings by examining differences between estimated age from digital portraits and chronological age (Δ age) for 180 women from three age groups (20–34, 35–49, 50–66 years) and five ethnicities (36 images of each ethnicity, assessed for age on a continuous scale by 120 female and male raters of each ethnicity).

Results

Across ethnicities, Δ age was smallest in French assessors and largest in South African assessors. Numerically, French women were judged oldest and Chinese women youngest relative to chronological age. In younger women, Δ age was larger than in middle‐aged and older women. This effect was particularly evident when considering the interaction of women's age with assessor gender and ethnicity, independently and together, on Δ age.

Conclusion

Collectively, our findings suggest that accuracy in assessments of female age from digital portraits depends on the chronological age and ethnicity of the photographed women and the ethnicity and gender of the assessor. We discuss the findings concerning ethnic variation in skin pigmentation and visible signs of ageing and comment on implications for cosmetic science.

Expert Consensus on Hyaluronic Acid Filler Facial Injection for Chinese Patients

Supplemental Digital Content is available in the text.

Background:

Beauty standards vary by race and region, which must be accounted for in creating beauty. Chinese have unique features, including a depressed nose, flat midface, and small chin, and have different cosmetic concerns. We performed a consensus study on filler injections based on the Chinese standard of beauty due to a lack of such study.

Methods:

We organized the YVOIRE Consensus Group, including 5 plastic surgeons. We discussed common problematic areas seen in Chinese and described techniques based on our experience with hyaluronic acid fillers, while considering peer-reviewed articles, followed by multiple consensus-developing sessions.

Results:

Chinese faces are characterized by retruded forehead, chin, and low nasal bridge, with certain features believed to bring good fortune. Therefore, profiles of the forehead, nose, lip, and chin have substantial effects on attractiveness. The demand for cosmetic procedures is high among the young generation who particularly desire nose and chin augmentation. Attractive Chinese facial shapes are characterized by a long, slender facial shape and pointed chin. Lips are narrow and thick. When injecting fillers for Chinese, it is necessary to apply special methods that produce results consistent with these characteristics.

Conclusions:

Understanding the concept and demand of beauty depending on race and region is important. Patients should be evaluated before aesthetic procedures. Maintaining hygiene during the procedure is crucial. Moreover, methods for preventing pain are essential. Fillers should be injected into the correct anatomical site and layer to minimize side effects and maximize effectiveness.

Have We Just Scratched the Surface? A Narrative Review of Uremic Pruritus in 2020

Purpose of review:

Uremic pruritus is a highly prevalent and debilitating symptom in patients with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). The purpose of this review is to examine current evidence on the mechanisms and treatments of pruritus in CKD and highlight promising areas for future research.

Sources of information:

Published literature, including randomized controlled trials, cohort studies, case reports, and review articles, was searched for evidence pertaining to the pathophysiology and treatment of uremic pruritus.

Methods:

A comprehensive narrative review was conducted to explore the molecular mechanisms underlying uremic pruritus, as well as the evidence (or lack thereof) supporting pharmacological and nonpharmacological treatments for uremic pruritus. The potential role of patient sex in the pathophysiology and management of uremic pruritus is also discussed.

Key findings:

The pathophysiology of uremic pruritus involves a complex interplay of uremic toxins, systemic inflammation, mast cell activation, and imbalance of opioid receptors. Classic treatment strategies for uremic pruritus include optimization of dialysis parameters, amelioration of CKD-related mineral and bone disease, topical emollients and analgesics, antihistamines, the anticonvulsant medications gabapentin and pregabalin, and ultraviolet light B (UV-B) phototherapy. Strong data to support many of these classical treatments for uremic pruritus are limited. Newly evolving treatment approaches for uremic pruritus include opioid receptor modulators, neurokinin-1 inhibitors, and cannabinoids. Further studies regarding their efficacy, pharmacodynamics, and safety in the CKD and ESKD population are needed before these agents are accepted into widespread use. Additional nonpharmacological strategies aimed at treating uremic pruritus include psychotherapy, acupuncture, omega-3 fatty acids, and exercise. Finally, sex differences may exist regarding uremic pruritus, but studies directly addressing sex-specific mechanisms of uremic pruritus remain absent.

Limitations:

High-quality evidence in the management of uremic pruritus remains lacking. Most recommendations are based on expert opinion or studies involving small numbers of patients. In addition, our understanding of the pathophysiological mechanisms behind uremic pruritus is incomplete and continues to evolve over time.

Implications:

Uremic pruritus is a common symptom which reduces quality of life in CKD and ESKD. The identification of novel targeted treatment approaches may ease the burden of uremic pruritus in the future.

Safety of light emitting diode-red light on human skin: Two randomized controlled trials

Therapeutic applications of light emitting diode-red light (LED-RL) are expanding, yet data on its clinical effects are lacking. Our goal was to evaluate the safety of high fluence LED-RL (≥160 J/cm² ). In two phase I, single-blind, dose escalation, randomized controlled trials, healthy subjects received LED-RL or mock irradiation to the forearm thrice weekly for 3 weeks at fluences of 160-640 J/cm² for all skin types (STARS 1, n = 60) and at 480-640 J/cm² for non-Hispanic Caucasians (STARS 2, n = 55). The primary outcome was the incidence of adverse events (AEs). The maximum tolerated dose was the highest fluence that did not elicit predefined AEs. Dose-limiting AEs, including blistering and prolonged erythema, occurred at 480 J/cm² in STARS 1 (n = 1) and 640 J/cm² in STARS 2 (n = 2). AEs of transient erythema and hyperpigmentation were mild. No serious AEs occurred. We determined that LED-RL is safe up to 320 J/cm² for skin of color and 480 J/cm² for non-Hispanic Caucasian individuals. LED-RL may exert differential cutaneous effects depending on race and ethnicity, with darker skin being more photosensitive. These findings may guide future studies to evaluate the efficacy of LED-RL for the treatment of various diseases.

Understanding rates of genital-anal injury: Role of skin color and skin biomechanics

PURPOSE

A series of studies suggest that non-Hispanic White women have significantly more injuries than non-Hispanic Black women after sexual assault and consensual sexual intercourse. One explanation for this difference is that the degree of skin protection may vary as skin mechanics and skin pigmentation vary. The aim of the study was to determine the association among genital-anal injury, skin color, skin viscoelasticity and skin hydration in women following consensual sexual intercourse when controlling for age, smoking history, body mass index (BMI), sun exposure, and health status.

PROCEDURES

We employed a prospective cohort study design to enroll women 21 years of age or older at two study sites. They underwent two data collection sessions, baseline and follow-up after consensual sexual intercourse. Baseline genital-anal injury identification occurred with a standard forensic examination (direct visualization, nuclear staining with toluidine blue contrast, and colposcopy examination) and measurements of other variables (skin color, skin viscoelasticity, skin hydration, age, smoking history, body mass index [BMI], sun exposure, and health status). Participants were then asked to have consensual sexual intercourse with a male partner of their choice and to return for a second forensic examination for injury detection. Genital-anal injury was regressed on skin color, skin viscoelasticity, skin hydration, age, smoking history, BMI, sun exposure, and health status.

FINDINGS

We enrolled 341 participants, 88 non-Hispanic White (25.8%), 54 non-Hispanic Black (15.8%), 190 Hispanic/Latina (55.7), and 9 Other Identities (2.6%). At baseline the genital-anal injury prevalence was 57.77% and at follow-up after consensual sexual intercourse, injury prevalence was 72.73%. External genital injury prevalence was associated with increased L* (lightness) values (Adjusted Odds Ratio [AOR] = 1.98, 95% Confidence Interval [CI] = 1.03, 4.04) and decreased skin elasticity (AOR = 0.96, 95% CI = 0.93, 0.99) at baseline. Increased skin hydration was associated with a significantly higher frequency of external, internal, anal, and total genital-anal injuries (Adjusted Rate Ratio [ARR] > 1.27) at follow-up. Also at the follow-up examination, Hispanic/Latina participants had significantly lower external genital and total genital-anal injury prevalence and frequency as compared to non-Hispanic White participants (AOR < 0.40).

CONCLUSIONS

Our findings provide qualified support for the importance of skin color during the forensic examination. Women with lighter skin tones may have skin that is more easily injured than women with darker tones. In contrast, external genital injuries may be more easily identified in women with light as compared to dark skin, a situation that is important in both the health care and criminal justice systems. Additionally, women with decreased viscoelasticity and increased hydration may be more easily injured. These findings support the need to develop forensic procedures that are effective in people across the range of skin colors and to interpret forensic findings considering the innate properties of the skin.

Occupational differences in standardized mortality ratios for non-melanotic skin cancer and melanoma in exposed areas among individuals with Fitzpatrick skin types III and IV

OBJECTIVE

The objective of this study was to identify subpopulations vulnerable to skin cancer by occupations, among individuals with Fitzpatrick skin types III and IV.

METHODS

Data were retrieved from the national mortality registry of Korean National Statistical Office (KNSO) from 1993 to 2012, including all medical certificates of death written and confirmed by physicians. Medical certificates of death from 1993 to 2012 were obtained from the national mortality registry of Korean National Statistical Office. These completed medical certificates are verified by the Korean Ministry of Government Administration and Home Affairs and formatted using 103 main and 236 specific causes of death as recommended by the World Health Organization. We calculated direct standardized mortality rate and standardized mortality ratio (SMR) using the indirect standardization method. The entire population as reflected in the 2005 national census was used as a reference population.

RESULTS

Of 594 deaths from skin cancer, 227 (38.2%) were from non-melanotic skin cancer (NMSC) and 367 (61.8%) from cutaneous melanoma (CM). Compared to office workers, agriculture/fishery/forestry workers had significantly higher SMRs for NMSC in men [SMR: 461, 95% confidential interval (CI): 329-583] and women (SMR: 575, 95% CI: 317-864). SMR was also increased in men who worked in exposed area (SMR of NMSC:553, 95% CI:222-1018, SMR of CM:453, 95% CI: 133-1009).

CONCLUSION

This is the first Asian study to suggest that agriculture/fishery/forestry workers have increased SMRs for NMSC and CM in exposed areas. Early diagnosis of skin cancer in this group is important.

Personalized skincare: from molecular basis to clinical and commercial applications

Individual responses of human skin to the environmental stress are determined by differences in the anatomy and physiology that are closely linked to the genetic characteristics such as pigmentation. Ethnic skin phenotypes can be distinguished based on defined genotypic traits, structural organization and compartmentalized sensitivity to distinct extrinsic aging factors. These differences are not only responsible for the variation in skin performance after exposure to damaging conditions, but can also affect the mechanisms of drug absorption, sensitization and other longer term effects. The unique characteristics of the individual skin function and, particularly, of the ethnic skin type are currently considered to shape the future of clinical and pharmacologic interventions as a basis for personalized skincare. Individual approaches to skincare render a novel and actively growing area with a range of biomedical and commercial applications within cosmetics industry. In this review, we summarize the aspects of the molecular and clinical manifestations of the environmental stress on human skin and proposed protective mechanisms that are linked to ethnic differences and pathophysiology of extrinsic skin aging. We subsequently discuss the possible applications and translation of this knowledge into personalized skincare.

Consensus Recommendations for Combined Aesthetic Interventions in the Face Using Botulinum Toxin, Fillers, and Energy-Based Devices

BACKGROUND

The aging process is a complex interplay of intrinsic and extrinsic factors across multiple layers of the face. Accordingly, combining aesthetic interventions targeting different manifestations of aging often leads to better results than single modalities alone. However, no guidelines for a pan-facial approach using multiple interventions have been published to date.

OBJECTIVE

To develop consensus recommendations for the optimal combination and ideal sequence of botulinum toxin (BoNT), hyaluronic acid, calcium hydroxylapatite, and microfocused ultrasound with visualization (MFU-V) in persons of all Fitzpatrick skin types.

METHODS AND MATERIALS

Fifteen specialists convened under the guidance of a certified moderator. Consensus was defined as approval from 75% to 94% of all participants, whereas agreement of ≥95% denoted a strong consensus.

RESULTS

Optimal aesthetic treatment of the face begins with a thorough patient assessment and an individualized treatment plan. Spacing consecutive treatments 1 to 2 weeks apart allows for resolution of side effects and/or to assess results. For same-day treatments, BoNT and fillers may be performed together in either sequence, whereas MFU-V is recommended before injectable agents.

CONCLUSION

Expert consensus supports a combination approach using multiple modalities in specific sequence for the safe and effective treatment of the aging face.

Thermal Response of In Vivo Human Skin to Fractional Radiofrequency Microneedle Device

Background. Fractional radiofrequency microneedle system (FRMS) is a novel fractional skin resurfacing system. Data on thermal response to this fractional resurfacing technique is limited. Objectives. To investigate histologic response of in vivo human skin to varying energy settings and pulse stacking of a FRMS in dark-skinned subjects. Methods. Two female volunteers who were scheduled for abdominoplasty received treatment with a FRMS with varying energy settings at 6 time periods including 3 months, 1 month, 1 week, 3 days, 1 day, and the time immediately before abdominoplasty. Biopsy specimens were analyzed using hematoxylin and eosin (H&E), Verhoeff-Van Gieson (VVG), colloidal iron, and Fontana-Masson stain. Immunohistochemical study was performed by using Heat Shock Protein 70 (HSP70) antibody and collagen III monoclonal antibody. Results. The average depth of radiofrequency thermal zone (RFTZ) ranged from 100 to 300 μm, correlating with energy levels. Columns of cell necrosis and collagen denaturation followed by inflammatory response were initially demonstrated, with subsequent increasing of mucin at 1 and 3 months after treatment. Immunohistochemical study showed positive stain with HSP70. Conclusion. A single treatment with a FRMS using appropriate energy setting induces neocollagenesis. This wound healing response may serve as a mean to improve the appearance of photodamaged skin and atrophic scars.

Assessment of the variation of skin barrier function with anatomic site, age, gender and ethnicity

The skin is the largest organ of the human body and its functions include protection, thermoregulation sensation and secretion. Significant advances in our understanding of how the morphology and physiology of the skin contribute to the skin's barrier role have been achieved in recent years. The aim of this review is to summarize the principal approaches which have been used to assess variation in skin barrier function with anatomic site, age, gender, and ethnicity. The methods discussed include trans-epidermal water loss (TEWL) measurement, assessment of corneocyte size, response to vasoactive compounds and attenuated total reflectance Fourier transform infrared (ATR-FTIR) interrogation of skin. The utility of the various methods is considered and the most important findings in the literature to date are highlighted.

Variation of stratum corneum biophysical and molecular properties with anatomic site

Several serine protease enzymes are known to be involved in both normal desquamation and the inflammatory processes of the skin. Alteration in the activity of these proteases should also affect corneocyte maturity and size as well as stratum corneum thickness. The aim of the present work was to characterise the baseline changes in corneocyte size, corneocyte maturity, selected protease activity (specifically, Kallikreins-5 and 7, tryptase), protein content and trans-epidermal water loss (TEWL) as a function of anatomic site. The anatomic sites investigated were: cheek, abdomen, wrist and mid-ventral forearm. TEWL values were highest for the cheek (p < 0.05). The TEWL values were also significantly higher (p < 0.05) for cheek and wrist compared with other sites. Protein content was significantly lower for wrist (p < 0.05) compared with other sites. Corneocyte maturity and surface area were significantly (p < 0.05) lower for cheek and wrist compared with other sites. An excellent correlation (r (2) = 0.99) was obtained for maturity and surface area measurements. Kallikrein-5 and tryptase activity were significantly higher for the cheek compared with other sites but Kallikrein-7 values were uniform across sites. The findings have significant implications for skin permeability to drugs and other substances such as environmental toxins depending on the anatomic site of delivery or exposure.

Skin viscoelasticity: physiologic mechanisms, measurement issues, and application to nursing science

Skin is the primary interface between health care providers and patients and is assessed clinically to predict physiological stability or instability. The biomechanical properties of human skin, most notably elasticity and viscoelasticity, are critical to its protective function. In this article, the authors describe the physiological basis for skin elasticity and viscoelasticity. The authors discuss the role of viscoelasticity in nursing science and consider avenues for scientific exploration of the skin's biomechanical properties, including applications in pressure ulcer research, injury, and healing. They also discuss the Cutometer® as one option for measurement of viscoelasticity in clinical and bench research protocols.

Defective barrier function in melasma skin

BACKGROUND

Melasma is characterized by increased pigmentation and photodamaged features, which include solar elastosis. Recently, we detected the downregulation of the genes most associated with lipid metabolism using microarray analysis in melasma. These findings suggested that lesional skin may have different biophysical characteristics, and, in particular, an altered skin barrier function.

OBJECTIVE

To determine the cutaneous biophysical characteristics of melasma.

METHODS

The melanin index, erythema index, stratum corneum hydration, sebum content and transepidermal water loss (TEWL) were measured for lesional and perilesional normal skin of 16 melasma patients and then compared. In addition, a skin biopsy was performed on 11 of the 16 study subjects to measure stratum corneum thickness and to study the protein expressions of PPAR-α and ALOX15B.

RESULTS

Melanin index, erythema index and stratum corneum hydration were significantly higher in lesional skin than in perilesional normal skin. No significant difference was found between lesional and normal skin in terms of basal TEWL level or sebum content. However, the rate of TEWL after barrier perturbation was significantly higher for lesional skin, and the barrier recovery rate was significantly delayed. Furthermore, a trend towards thinned stratum corneum was observed for lesional skin, and this was correlated with barrier recovery rate. The expressions of PPAR-α and ALOX15B were variable in the samples.

CONCLUSIONS

Melasma skin is characterized by impaired stratum corneum integrity and a delayed barrier recovery rate.

Skin care in ethnic populations

Use of over-the-counter cosmetics, approaches to hygiene, and many basic dermatologic principles differ between individuals with Caucasian skin and ethnic skin. Still, comparatively few publications highlight these variations or discuss appropriate management. Among many ethnic patients, issues related to skin hydration, restoration of even pigmentation, hair removal, and acne care remain problematic yet not fully addressed. As well, there are some dermatologic conditions that may be rare in Caucasian skin but are much more common in the ethnic patient. Here, we discuss various aspects of skin hydration, dyschromia, sunscreen use, and chemical depilatories in the ethnic population.

Structural and functional differences in barrier properties of African American, Caucasian and East Asian skin

BACKGROUND

Differences in structural and functional skin characteristics have been linked with ethnical background. But racial differences in skin have not been thoroughly investigated by objective methods and the data are often contradictory.

OBJECTIVES

This study was undertaken to compare skin barrier-related parameters of the stratum corneum on African American, Caucasian and East Asian skin by objective measurements.

METHODS

Baseline values of trans epidermal water loss were collected on the face. Consecutive stratum corneum D-squame tape strippings were collected on the panelist's ventral forearm and face to evaluate skin barrier strength and cohesion. Stratum corneum ceramides, maturation, measured as the transglutaminase-mediated cross-linking of stratum corneum proteins, and stratum corneum trypsin like enzyme activity were measured on the D-squame tape strippings.

RESULTS

East Asian and to some extent Caucasian skin was characterized by low maturation and relatively weak skin barrier. African American skin was characterized by low ceramide levels and high protein cohesion in the uppermost layers of the stratum corneum. These data can be interpreted in terms of the high prevalence of xerosis in black skin and increased skin sensitivity in East Asian skin.

CONCLUSION

These results demonstrate that skin properties at the level of the stratum corneum vary considerably among these ethnic groups. This contributes to an improved understanding of physiological differences between these study populations.

Percutaneous absorption and exposure assessment of pesticides

Dermal exposure to a diverse range of chemicals may result from various uses. In order to assess exposure and estimate potential risks, accurate quantitative data on absorption are required. Various factors will influence the final results and interpretations of studies designed to assess the ability of compounds to penetrate the skin. This overview will discuss skin penetration by pesticides, emphasizing key parameters to be considered from the perspective of exposure assessment.

Cultured autologous keratinocytes in suspension accelerate epithelial maturation in an in vivo wound model as measured by surface electrical capacitance

BACKGROUND

Human epidermis serves as a protective covering against loss of endogenous fluids and exogenous microbial invasion. Cultured epithelial autograft suspensions have been used to enhance epithelialization to improve mortality, morbidity, and the overall quality of the scar. The measurement of surface electrical capacitance as an indicator of transepidermal water loss has been used in neonatology and dermatology to determine epidermal maturation. This tool has been used in a double-blind, randomized, controlled trial to compare the effects of cultured epithelial autograft in suspension on epidermal healing and maturation compared with a control in an in vivo partial thickness wound model.

METHODS

In this double-blind, randomized, controlled trial (n = 8), the authors assessed the effect of cultured epithelial autograft on epidermal healing and maturation in standardized partial thickness wounds. Surface electrical capacitance was compared on 16 split-thickness skin graft donor sites treated with cultured epithelial autograft (n = 8) against controls treated with Dulbecco's Modified Eagle's Medium (n = 8) using a NOVA Dermaphase Meter at 4, 5, 6, and 7 days postoperatively.

RESULTS

A statistically significant difference on continuous readings at days 5 (p = 0.012) and 7 (p = 0.036) and instantaneously on days 5 (p = 0.025) and 6 (p = 0.036) in surface electrical capacitance was observed in the cultured epithelial autograft over the Dulbecco's Modified Eagle's Medium-treated wounds.

CONCLUSIONS

Measuring surface electrical capacitance provides an objective and repeatable method of assessing epidermal maturation. This study indicates that the rate of epithelialization and epidermal maturation is more rapid in partial thickness epidermal skin wounds treated with cultured epithelial autograft.

Sensory, clinical and physiological factors in sensitive skin: a review

Certain individuals experience more intense and frequent adverse sensory effects than the normal population after topical use of personal care products, a phenomenon known in popular usage as sensitive skin. Consumer reports of sensitive skin are self-diagnosed and often not verifiable by objective signs of physical irritation. Companies who manufacture cosmetic and personal care products are challenged to provide safe products to an audience with tremendous differences in skin type, culture and habits. This review examines the still incomplete understanding of this phenomenon with respect to aetiology, diagnosis, appropriate testing methods, possible contributing host factors such as, sex, ethnicity, age, anatomical site, cultural and environmental factors, and the future directions needed for research.

Ethnic or Racial Differences Revisited

Ethnic or racial differences in pharmacokinetics and pharmacodynamics have been attributed to the distinctions in the genetic, physiological and pathological factors between ethnic/racial groups. These pharmacokinetic/pharmacodynamic differences are also known to be influenced by several extrinsic factors such as socioeconomic background, culture, diet and environment. However, it is noted that other factors related to dosage regimen and dosage form have largely been ignored or overlooked when conducting or analysing pharmacokinetic/pharmacodynamic studies in relation to ethnicity/race. Potential interactions can arise between the characteristics of ethnicity/race and a unique feature of dosage regimen or dosage form used in the study, which may partly account for the observed pharmacokinetic/pharmacodynamic differences between ethnic/racial groups. Ethnic/racial differences in pharmacokinetics/pharmacodynamics can occur from drug administration through a specific route that imparts distinct pattern of absorption, distribution, transport, metabolism or excretion. For example, racial differences in the first-pass metabolism of a drug following oral administration may not be relevant when the drug is applied to the skin. On the other hand, ethnic/racial difference in pharmacokinetics/pharmacodynamics can also happen via two different routes of drug delivery, with varying levels of dissimilarity between routes. For example, greater ethnic/racial differences were observed in oral clearance than in systemic clearance of some drugs, which might be explained by the pre-systemic factors involved in the oral administration as opposed to the intravenous administration. Similarly, changes in the dose frequency and/or duration may have profound impact on the ethnic/racial differences in pharmacokinetic/pharmacodynamic outcome. Saturation of enzymes, transporters or receptors at high drug concentrations is a possible reason for many observed ethnic/racial discrepancies between single- and multiple-dose regimens, or between low- and high-dose administrations. The presence of genetic polymorphism of enzymes and/or transporters can further complicate the analysis of pharmacokinetic/pharmacodynamic data in ethnic/racial populations. Even within the same dosage regimen, the use of different dosage forms may trigger significantly different pharmacokinetic/pharmacodynamic responses in various ethnic/racial groups, given that different dosage forms may exhibit different rates of drug release, may release the drug at different sites, and/or have different retention times at specific sites of the body. It is thus cautioned that the pharmacokinetic/pharmacodynamic data obtained from different ethnic/racial groups cannot be indiscriminately compared or combined for analysis if there is a lack of homogeneity in the apparent 'extrinsic' factors, including dosage regimen and dosage form.

Vulvar susceptibility to contact irritants and allergens: a review

Vulvar tissue differs from cutaneous epithelia in structure, morphology and biophysical characteristics. For example, the skin of the labia majora exhibits elevated hydration, occlusion and frictional properties, which may increase susceptibility to irritants and contact sensitizers. Furthermore, the nonkeratinized vulvar vestibule is likely to be more permeable than keratinized regions. These differences heighten vulvar susceptibility to topical agents. This reviews the structure and properties of vulvar tissue, emphasizing their impact on susceptibility contact irritants and allergens.

Black/White differences in pressure ulcer incidence in nursing home residents

OBJECTIVES

To compare black and white nursing home residents with respect to the incidence of nursing home (NH)-acquired pressure ulcers (PUs) and to examine the role of resident characteristics and facility characteristics in explaining differences between the racial groups.

DESIGN

Prospective cohort study conducted between 1992 and 1995.

SETTING

Fifty-nine Maryland NHs.

PARTICIPANTS

A total of 1,938 residents (301 black, 1,637 white) aged 65 and older newly admitted to participating NHs.

MEASUREMENTS

The outcome variable was the first occurrence of a Stage 2, 3, or 4 PU as determined based on medical record review. The predictor variable was race (black, white). Eight resident characteristics (age, sex, number of activity of daily living dependencies, bedfast, PU on admission to facility, incontinence, dementia, and whether the resident was on Medicaid) and three facility characteristics (number of beds, for-profit ownership status, and urban/nonurban location) were considered as possible confounding variables.

RESULTS

The incidence of PUs was 0.38 per person-year in the NH. The rate for blacks was significantly higher than for whites (0.56 vs 0.35 per person-year) (P<.001). In multivariate analysis, controlling for eight resident characteristics and three facility characteristics, race was significantly associated with PU incidence (hazard ratio comparing blacks with whites=1.31, 95% confidence interval=1.02-1.66).

CONCLUSION

Blacks have a higher incidence of NH-acquired PUs than whites; resident characteristics appear to mediate the higher risk. Future research should aim to identify modifiable factors that explain differences between racial groups in PU risk and to develop solutions to prevent the suffering and cost associated with PUs.

A review of trabeculectomy in East Asian people—the influence of race

Glaucoma is the leading cause of irreversible blindness worldwide. East Asians account for approximately half of all glaucoma sufferers. It is likely that trabeculectomy will be needed for many of these people as the intraocular pressure is to be maintained at a satisfactorily low level. The eyes of East Asian people differ in some aspects from those of other races. This review describes the natural history of the eye after trabeculectomy in East Asians.

Structure and function of ethnic skin and hair

Differences have been found among blacks, whites, Asians, and Hispanics in various areas of skin structure and function. Among them is the stratum corneum lipid (ceramide) content, which is highest in Asians, then Hispanics, then whites, and lowest in blacks. Melanosomal packaging and percutaneous absorption rates for specific compounds also vary among the different races. Reports supporting the occurrence of difference in TEWL, tyrosinase levels, skin elasticity, and water absorption rates between blacks and whites, and reaction to skin irritation have been conflicting. No significant differences in corneocyte size, skin thickness, and skin biomechanics have been reported.

Cosmetic considerations and nonlaser cosmetic procedures in ethnic skin

The face of the aesthetic patient is changing to be more representative of the ethnic diversity of the United States population. It is imperative that the cosmetic dermatologic surgeon not only understand the concerns of the ethnic aesthetic patient but have an awareness of the unique needs of those with darker skin.

Effects of age and race on skin condition and bacterial counts on hands of neonatal ICU nurses

OBJECTIVE

The purpose of this study was to assess the relationship between demographic factors such as age and race and skin condition and bacterial counts on hands of nurses.

METHODS

Nurses (n = 111) working in 1 of 2 neonatal ICUs in New York City were surveyed regarding reported hand care practices and demographics, the condition of their hands was assessed by a trained observer and by themselves using validated instruments, and a hand culture was obtained.

RESULTS

There were no significant differences in any skin care practices by race, but nurses who wore powder-free gloves were significantly younger than those who did not (P =.004). There were no significant differences in bacterial counts on hands of black or white nurses (mean log colony-forming units 3.49 and 3.61 respectively, P =.63) and no significant correlation between age and microbial counts (r = 0.04, P =.72). In a logistic regression analysis, race, but not age, was a significant predictor of skin health. By both observer (P =.02) and self-assessment (P =.004) black nurses had healthier skin.

CONCLUSION

Physiochemical differences in skin associated with demographic factors such as age and race may be exacerbated among those in disciplines such as nursing, for whom the skin of the hands is continually stressed by occupational practices such as frequent hand hygiene. Such demographic factors need be considered when assessing skin condition and when advocating for appropriate strategies to maximize skin health. The recommendations of the new CDC Hand Hygiene Guideline for Healthcare Settings(23) regarding maintaining skin health and providing moisturizers and products that are milder to the skin are timely and should be followed.

Ethnic skin: overview of structure and function

Racial variability in skin function is an area in which data often conflict. Understanding and quantifying racial differences in skin function are important for skin care and the prevention and treatment of skin diseases. A key feature that characterizes race is skin color: Is deeply pigmented skin different from fair skin in terms of responses to chemical and environmental insults? Is skin care the same? Are there different risks among racial groups of developing a skin disease after exposure to the same insults? The interpretation of pathophysiologic phenomena should consider not only anatomic and functional characteristics of ethnic groups but also socioeconomic, hygienic, and nutritional factors. This article reviews and discusses recent findings.

Ethnicity as a possible endogenous factor in irritant contact dermatitis: comparing the irritant response among Caucasians, blacks, and Asians

Irritant contact dermatitis (ICD) is a common dermatological diagnosis in which endogenous and exogenous factors have been implicated. This review explores ethnicity as a possible endogenous factor. While there is a clinical consensus that blacks are less reactive and Asians are more reactive than Caucasians, the data supporting this hypothesis rarely reaches statistical significance. The studies reviewed do not provide sufficient evidence to determine that race is a predisposing factor to the degree of irritation in ICD. We conclude that race could be a factor in ICD, which has practical consequences regarding topical product testing requirements, an ever-expanding global market, occupational risk assessment, and the clinical thinking about ICD. Pitfalls in defining differences are discussed.

Ethnic variations in self-perceived sensitive skin: epidemiological survey

To examine possible ethnic variations in perception of sensitive skin, an epidemiological survey was performed in the San Francisco area. Approximately 800 telephone interviews were conducted with women from four different ethnic groups (Afro-Americans, Asians, Euro-Americans, Hispanics; approximately 200 women per group). In addition to sensitive facial skin assessments, age and other general skin condition data were collected. 52% of the subjects identified themselves as having sensitive facial skin. There was no statistical difference between the ethnic groups in terms of sensitive skin prevalence. Nevertheless, some differences were noted between ethnic subgroups of sensitive skin. Euro-Americans were characterized by a higher skin reactivity to wind and tended to be less reactive to cosmetics. Afro-Americans presented diminished skin reactivity to most environmental factors and a lower frequency of recurring facial redness. Asians appeared to have greater skin reactivity to spicy food, to sudden changes in temperature and to wind, and tended to suffer from itching more frequently. Hispanics presented a lower incidence of skin reactivity to alcohol. The differences in skin sensitivity between ethnic groups concerned mostly factors of skin reactivity and, to a lesser extent, its symptomatology. But, taken together, we note the similarities in comparing how women of varying ethnic backgrounds perceive the sensitive skin condition.

The antimicrobial properties of melanocytes, melanosomes and melanin and the evolution of black skin

A biological issue that has not been satisfactorily resolved is the role of melanin in skin and other animal tissues. A hypothesis is outlined here to account for the evolution of black skin and the ubiquity of melanin in vertebrate tissues. Evidence is presented that melanization of skin and other tissues forms an important component of the innate immune defense system. A major function of melanocytes, melanosomes and melanin in skin is to inhibit the proliferation of bacterial, fungal and other parasitic infections of the dermis and epidermis. This function can potentially explain (a) the latitudinal gradient in melanization of human skin; (b) the fact that melanocyte and melanization patterns among different parts of the vertebrate body do not reflect exposure to radiation; (c) provide a theoretical framework for recent empirical findings concerning the antimicrobial activity of melanocytes and melanosomes and their regulation by known mediators of inflammatory responses.

Tacrolimus ointment for the treatment of atopic dermatitis in adult patients: part I, efficacy

A total of 632 adults with atopic dermatitis applied tacrolimus ointment (0.03% or 0.1%) or vehicle twice daily for up to 12 weeks in two randomized, double-blind studies. This report focuses on the efficacy of tacrolimus ointment in these studies. The mean percent body surface area (%BSA) affected at baseline was 45%, and 56% of patients had severe atopic dermatitis. Evaluations included a physician's global evaluation of clinical response, %BSA affected, individual signs of atopic dermatitis, the Eczema Area and Severity Index (EASI) score, and the patient's assessment of pruritus. A 90% or greater improvement from baseline in disease status was observed for 6.6%, 27.5%, and 36.8% of patients in the vehicle, 0.03% tacrolimus ointment, and 0.1% tacrolimus ointment groups, respectively (P<.001), and 50% or better improvement was observed for 19.8%, 61.6%, and 72.7% of patients, respectively. Tacrolimus ointment-treated patients showed significantly greater improvement than vehicle-treated patients for all efficacy parameters evaluated, including the %BSA affected, the total score and individual scores for signs of atopic dermatitis, the patient's assessment of pruritus, and EASI score. The 0.1% concentration was more effective than the 0.03% concentration, particularly in patients with severe disease and/or extensive BSA involvement at baseline and in African Americans. Tacrolimus ointment is an effective therapy for the treatment of adult patients with atopic dermatitis on all skin regions including the head and neck.

Skin and hair cosmetic issues in women of color

Women of color comprise many phenotypically heterogeneous groups. Despite the general heterogeneity, however, there are unique skin and hair care issues and needs. These issues often present therapeutically challenging problems for the dermatologist and the skin and hair care industry.

Effects of glycolic acid on light-induced skin pigmentation in Asian and caucasian subjects

BACKGROUND

Topical use of alpha-hydroxy acid (AHA) may increase skin photosensitivity, as demonstrated by increased numbers of sunburst cells. However, effects of AHA on tanning have not been studied.

OBJECTIVE

Our purpose was to study whether short-term use of glycolic acid hastens resolution of pre-existing light-induced pigmentation and whether the skin becomes tan more easily in Asian and Caucasian subjects after such treatment.

METHODS

Six Asian and six Caucasian volunteers received separate irradiations of UVB and UVA to both sides of the lower back. In a double-blind fashion, patients then applied a 10% glycolic acid gel, pH 3.52, to one side of the back, including the irradiated area, and the contralateral extensor forearms once daily for 7 days and then twice daily for 2 weeks. A placebo gel, pH 5.75, was applied to the opposite sides. The subjects returned for measurement of residual tanning with a colorimeter and received additional irradiation to forearms and a second site on the back. Resulting pigmentation was measured immediately after irradiation, at 2 hours, and at 1 week.

RESULTS

Increased UVB-induced skin tanning occurred on the forearm and the lower back in both races in areas pretreated with glycolic acid. UVA also caused increased tanning, but only on the extensor forearms in Asian subjects. Treatment with glycolic acid for 3 weeks had no effect on pre-existing light-induced pigmentation.

CONCLUSION

Short-term topical treatment of glycolic acid caused an increase in UVB tanning as well as in UVA tanning in some subjects, even in the absence of overt irritation. The inclusion of UVB, and even UVA, sunscreen in AHA products may be warranted.

Effect of saline iontophoresis on skin barrier function and cutaneous irritation in four ethnic groups

The effect of saline iontophoresis on skin barrier function and irritation was investigated in four ethnic groups (Caucasians, Hispanics, Blacks and Asians). Forty healthy human volunteers were recruited according to specific entry criteria. Ten subjects, five males and five females, were assigned to each ethnic group. Skin barrier function was examined after 4 hours of saline iontophoresis at a current density of 0.2 mA/cm(2) on a 6.5 cm(2) area in terms of the measured responses: transepidermal water loss (TEWL), skin capacitance, skin temperature and visual scores. There were significant differences in TEWL among the ethnic groups prior to patch application. TEWL at baseline in ethnic groups was in the rank order: Caucasian>Asian>Hispanic>Black. Iontophoresis was generally well tolerated, and skin barrier function was not irreversibly affected by iontophoresis in any group. There was no significant skin temperature change, compared to baseline, in any ethnic groups at any observation point. Edema was not observed. At patch removal, the erythema score was elevated in comparison to baseline in all ethnic groups; erythema resolved within 24 hours. Thus, saline iontophoresis produced reversible changes in skin barrier function and irritation in healthy human subjects.