Structural changes in dermal collagen and oxidative stress levels in the skin of Japanese overweight males

Histological Skin Assessment of Patients Submitted to Bariatric Surgery: A Prospective Longitudinal Cohort Study

BACKGROUND

Obesity is a stigmatizing disease that can cause dermatological aberrations, such as sagging after rapid weight loss.

OBJECTIVE

This study is to evaluate the effects of obesity and massive weight loss following bariatric surgery on collagen and elastic fibers of the extracellular matrix of the skin.

METHODS

Thirty-three skin biopsies were collected from patients prior to bariatric surgery and one year after surgery. Histological analyses were performed using hematoxylin-eosin and Weigert's resorcin-fuchsin staining for collagen and elastic and elaunin fibers, respectively. Differences between means were submitted to the Student's t-test or Mann-Whitney U test, with p < 0.05 significant.

RESULTS

The study demonstrated an architectural alteration of the skin 1 year after bariatric surgery. In the histological analysis of the skin samples, a significant difference in the thickness of the epidermis was found 1 year after surgery in all age groups as well as in the 38-to-68-kg weight loss group (p < 0.0001). In addition to laxity, disorganization of collagen was found, with an apparent decrease in quantity and an increase in elastic fibers, although fragmented (p < 0.0001).

CONCLUSION

Obesity and massive weight loss following bariatric surgery cause the disorganization of collagen fibers and the fragmentation of elastic fibers of the extracellular matrix of the skin.

Skin optical properties in the obese and their relation to body mass index: a review

SIGNIFICANCE

Obesity is a worldwide epidemic contributing directly to several cardiovascular risk factors including hypertension and type 2 diabetes. Wearable devices are becoming better at quantifying biomarkers relevant for the management of health and fitness. Unfortunately, both anecdotal evidence and recent studies indicate that some wearables have higher levels of error when utilized by populations with darker skin tones and high body mass index (BMI). There is an urgent need for a better evaluation of the limits of wearable health technologies when used by obese individuals.

AIMS

(1) To review the current know-how on changes due to obesity in the skin epidermis, dermis, and subcutis that could affect the skin optical properties; (2) for the green wavelength range, to evaluate the difference in absorption and scattering coefficients from the abdominal skin between individuals with and without elevated BMI. The changes include alterations in layer thickness and cell size, as well as significant differences in chromophores and scatterer content, e.g., water, hemoglobin, collagen, and lipids.

APPROACH

We have summarized literature pertaining to changes in skin and its components in obesity and report the results of our search using articles published between years 1971 and 2020. A linear model was used to demonstrate the absorption and reduced scattering coefficient of the abdominal skin of individuals with and without elevated BMI in the green wavelength range (530 to 550 nm) that is typically found in most wearables.

RESULTS

The general trends indicate a decrease in absorption for both dermis and subcutis and an increase in reduced scattering for both epidermis and dermis. At 544-nm wavelength, a typical wavelength used for photoplethysmography (PPG), the absorption coefficient's relative percentage difference between high and low BMI skin, was 49% in the subcutis, 19% in the dermis, and negligible in the epidermis, whereas the reduced scattering coefficient relative difference was 21%, 29%, and 165% respectively.

CONCLUSIONS

These findings suggest that there could be significant errors in the output of optical devices used for monitoring health and fitness if changes due to obesity are not accounted for in their design.

High-Frequency Ultrasound Assessment of Skin and Oral Mucosa in Metabolic Syndrome Patients-A Cross-Sectional Study

Background: Exogenous factors (such as sun exposure, smoking habits, and diet) and endogenous (inflammatory status, general diseases) have a direct influence on skin and soft tissue characteristics. The study’s objective was to assess the impact of metabolic syndrome (MS) on characteristics of skin layers in sun-exposed and non-exposed maxillofacial tissues evaluated by high-frequency ultrasound (HFU), as a potential diagnosis and monitoring tool for the aging process. Material and methods: The present study included 102 subjects (24 with MS; 78 without MS). Anthropometric parameters and disease history were recorded, and blood samples were harvested in order to assess biochemical parameters of MS. Sun-exposed skin (zygomatic region) and non-exposed oral mucosa of the lower lip were assessed using HFU (DUB^® cutis, Taberna Pro Medicum) with a 22 MHz probe. Results: Patients with cardiac disease had significantly lower values for epidermis density (p = 0.002). Gender was independently linked to the aged dermis depth (p < 0.001), aged dermis no. of px (pixels) (p < 0.001), dermis depth (p < 0.001), dermis no. of px (p < 0.001), and subcutaneous tissue density (p < 0.001). Patients with MS had thinner epidermis (p = 0.008) and thinner aged dermis (p = 0.037) when compared to non-MS subjects. Conclusion: Patients with MS had thinner epidermis and a lower epidermis number of pixels in sun-exposed skin. Women had lower epidermis density and thicker dermis in sun-exposed skin. Our study showed that HFU, as a non-invasive investigation approach, is useful to diagnose and monitor the aging process in skin and oral mucosa, correlated with skin phenotype pathological conditions.

Obesity-associated insulin resistance adversely affects skin function

The aim of this study was to identify changes in skin function associated with obesity and the mechanisms underlying these changes. Functional changes and gene expression in skin were investigated in C57BL/6J mice fed either a control or high-fat diet (HFD). The insulin responsiveness of the skin and skeletal muscle was also evaluated. The effects of inhibiting insulin signaling and altered glucose concentration on skin function-associated molecules and barrier function were analyzed in keratinocytes. HFD-fed mice were not only severely obese, but also exhibited impaired skin barrier function and diminished levels of glycerol transporter aquaporin-3, keratins, and desmosomal proteins involved in maintaining skin structure. Moreover, the expression of cell cycle regulatory molecules was altered. Insulin signaling was attenuated in the skin and skeletal muscle of HFD-fed mice. In keratinocytes, inhibition of insulin signaling leads to decreased keratin expression and diminished barrier function, and higher glucose concentrations increased the expression of CDK inhibitor 1A and 1C, which are associated with cell-cycle arrest. Obesity-associated impairment of skin function can be attributed to structural fragility, abnormal glycerol transport, and dysregulated proliferation of epidermal cells. These alterations are at least partly due to cutaneous insulin resistance and hyperglycemia.

Microsatellite polymorphism in the Heme oxygenase-1 gene promoter is associated with dermal collagen density in Japanese obese male subjects

We previously reported elevated oxidative stress-related mechanical vulnerabilities of the skin as sparse distributions of hyperechoic areas. Although this helped establish a personalized skin care system to prevent skin disorders related to mechanical stress, obesity-related skin vulnerability involves individual differences. Here, we hypothesized that individual differences are caused by polymorphisms of GT repetitive sequences in the heme oxygenase1 (HMOX1) promoter region, which encodes an antioxidant enzyme. This cross-sectional study enrolled healthy male volunteers in a walking classroom aimed at weight control. Subjects with a body mass index <25 kg/m² were classified as non-obese and those with body mass index ≥25 kg/m² were classified as obese. Subject skin was categorized into sparse dermis or normal groups according to the distribution of hyperechoic areas by high-resolution skin ultrasonography (20 MHz). Genomic DNA and mRNA extracted from three body hairs with attached follicle cells were used to analyze GT repetitive sequences of the HMOX1 promoter, HMOX1 mRNA expression levels, and oxidative stress levels (8-hydroxy-2’-deoxyguanosine). Classifications of GT repetitive sequence of HMOX1 promoter were Short (<27 times) and Long (≥27 times). Higher numbers of subjects with sparse dermis were in the obese group compared with the non-obese group. In obese subjects, the number of subjects that had the Long allele of the HMOX1 promoter with sparse dermis was significantly higher compared with the normal group, whereas no association was observed between the polymorphism and ultrasonographic features in non-obese subjects. Thus, HMOX1 polymorphisms detected a risk of low collagen density in Japanese obese male subjects.

Aging-like physiological changes in the skin of Japanese obese diabetic patients

Objective:

Obesity-associated diabetes causes aging-like changes to skin physiology in animal models, but there have been no clinical studies focusing on human obese diabetic patients. The purpose of this study was to examine the hypothesis that obesity-associated diabetes accelerates aging-like skin changes in Japanese people.

Methods:

This cross-sectional study enrolled obese-diabetes patients (body mass index ≥ 25 kg m−2) and healthy volunteers (body mass index < 25 kg m⁻²) as controls. Skin physiology parameters relating to aging (stratum corneum hydration, transepidermal water loss, skin pH, advanced glycation end-products, and dermal collagen density) were evaluated in the two groups.

Results:

About 37 subjects participated (16 in a control group and 21 in an obese-diabetes group). Age was not significantly different between the groups. The stratum corneum hydration level was significantly lower in the obese-diabetes group. Transepidermal water loss and levels of advanced glycation end-products were significantly higher in this group. Skin pH was not significantly different between groups. Dermal collagen density decreased in the obese-diabetes group.

Conclusion:

We showed that obese-diabetes patients have decreased stratum corneum hydration, increased transepidermal water loss, higher skin advanced glycation end-products and decreased dermal collagen fiber density compared with normal-weight subjects. These results indicate that the ordinary age-related physiological skin changes seen in the elderly can also occur in obese-diabetes patients aged in their 40s.

Changes in dermal structure and skin oxidative stress in overweight and obese Japanese males after weight loss: a longitudinal observation study

BACKGROUND/PURPOSE

Previous studies have reported decreased dermal echogenicity and increased skin oxidative stress in overweight males. However, it is unknown whether these skin parameters of overweight and obese people are similar to those of individuals exhibiting a normal body weight following weight loss. The purpose of this study was to (1) compare the changes in the dermal structure parameters and levels of skin oxidative stress before and after weight loss in overweight and obese people in Japan and (2) to clarify how these aspects changed when body weight would be reduced to normal body weight.

METHODS

Male volunteers with a body mass index of ≥25 kg/m² were recruited. The dermal structure was visualized and dermal echogenicity and thickness were measured using ultrasound scanners. The mRNA expression level of heme oxygenase-1 in the hair follicles was quantitatively analyzed as a marker of skin oxidative stress.

RESULTS

When overweight individuals in their 20s to 30s reduced their weight to normal, decreased dermal thickness in the abdominal region was observed in 50% of the subjects; however, no increase in dermal echogenicity was observed. A decrease in dermal thickness and an increase in dermal echogenicity in the thighs was observed in 83.3% of the subjects. No decrease in the level of dermal oxidative stress was observed.

CONCLUSION

The dermal structure in the thighs of overweight young individuals can be improved to the level of the structure in those of normal body weight individuals following weight loss.