Obesity and ethnicity alter gene expression in skin

Abstract

Obesity is accompanied by dysfunction of many organs, but effects on the skin have received little attention. We studied differences in epithelial thickness by histology and gene expression by Affymetrix gene arrays and PCR in the skin of 10 obese (BMI 35-50) and 10 normal weight (BMI 18.5-26.9) postmenopausal women paired by age and ethnicity. Epidermal thickness did not differ with obesity but the expression of genes encoding proteins associated with skin blood supply and wound healing were altered. In the obese, many gene expression pathways were broadly downregulated and subdermal fat showed pronounced inflammation. There were no changes in skin microbiota or metabolites. African American subjects differed from European Americans with a trend to increased epidermal thickening. In obese African Americans, compared to obese European Americans, we observed altered gene expression that may explain known differences in water content and stress response. African Americans showed markedly lower expression of the gene encoding the cystic fibrosis transmembrane regulator characteristic of the disease cystic fibrosis. The results from this preliminary study may explain the functional changes found in the skin of obese subjects and African Americans. Obesity, defined as a body mass index (BMI) greater than 30 kg/m 21 , has become a major epidemic in industrial and emerging countries. The prevalence of obesity has doubled since the 1980s and it is now estimated that 600 million adults worldwide are obese 2. Obesity affects many organs of the body and it is this organ dysfunction that leads to excess mortality and morbidity 3. Much attention has focused on the consequences of obesity in the heart, liver and pancreas and other organs in which increased inflammation and oncogenesis become apparent 4. Less attention has been paid to the effects of obesity on the skin. Obesity increases psoriasis 5 , which can be ameliorated with weight loss, and cutaneous infections 6. Since diabetes is common in obesity, disorders such as fibroepithelial polyps and acanthosis nigricans also occur in the skin of obese subjects 7,8. Moreover, physiologic changes found in obese skin include increased trans-epidermal water loss with lower capacitance, dry, rough textured skin with pronounced erythema and reduced microvascular reactivity. Altered collagen formation and increased delayed-type hypersensitivity have also been reported 9. Adipocyte depots that exist adjacent to the epidermis have distinct morphology and physiologic characteristics and are termed dermal or subdermal adipose tissue. In addition to the principal role for dermal adipocytes in lipid storage and thermal insulation 10 , they also promote skin immunity 11 , wound healing, and hair follicle cycling 12. Obesity is accompanied by inflammatory immune changes in subcutaneous and visceral adipose tissues 13 , but the role of inflammatory changes within the adipose layer of the skin has received little attention. Furthermore, obesity is associated with increased circulating leptin...

Fatty acid profiles in various lipid fractions in the female epidermis. Does the body site and age matter?

“…The authors also verified the expression levels of two inflammation markers TNF-α and IL-6 which were not found to be correlated with BMI (Horie et al, 2018). In another study on obese (BMI 35-50) and non-obese postmenopausal women between the ages of 40 and 70 years, no differences in relation to the thickness of the epidermis between those groups were found, despite existing differences in gene expression profile (Walker et al, 2020). Furthermore, another study by Matsumoto et al, revealed that weight reduction leads to a decrease in epidermal thickness by about 50% of analysed obese males (Matsumoto et al, 2018).…”

Cranioplasty Outcomes From 500 Consecutive Neuroplastic Surgery Patients

“…Of note, we observed patients with increased BMI to be at particularly lower odds of infection. Pronounced increased subdermal inflammation has previously been observed in obese compared to nonobese skin samples, suggesting that baseline differences in inflammation may confer greater protection from infection 38. Future, studies are important to better understand the role of BMI and scalp thickness in influencing outcomes in cranioplasty.…”

“…Furthermore, it is unclear why racial identity affected the odds of having a major complication following cranioplasty. Previous studies have observed differences in soft tissue properties between White and Black patients, however, their effect on wound healing requires further investigation 38–40…”

“…Pronounced increased subdermal inflammation has previously been observed in obese compared to nonobese skin samples, suggesting that baseline differences in inflammation may confer greater protection from infection. 38 Future, studies are important to better understand the role of BMI and scalp thickness in influencing outcomes in cranioplasty. Furthermore, it is unclear why racial identity affected the odds of having a major complication following cranioplasty.…”

A practical guide to hidradenitis suppurativa

“…12,18,[26][27][28] Obesity is associated with maceration and mechanical stress, increased fragility of the dermo-epidermal junction, changes in cutaneous blood flow, and subdermal fat inflammation-all of which favor the pathophysiology of HS. 29,30 ❚ Smoking. Tobacco smoking is associated with severe HS and a lower chance of remission.…”