Inflammatory Cytokine Expression and Sebum Production after Exposure of Cultured Human Sebocytes to Ultraviolet A Radiation and Light at Wavelengths of 650 nm and 830 nm

3D artificial sebocyte glands from inertial focusing effect for facile and flexible analysis of light damage and drug screening

The sebaceous gland is a neuro-immuno-endocrine organ responsible for maintaining regular skin functions. Overdose exposure of UV and visible light (e.g., blue light) can cause sebocyte gland function disorders or even different diseases (e.g., chronic actinic dermatitis). Studying the mechanism of light-induced damage in sebaceous glands has been challenging, since ex vivo culture of sebaceous glands is difficult due to its short life in culture medium. To address this issue, a versatile 3D artificial sebocyte gland model was established using the inertial focusing effect for studying the impact of light damage and screening potential drugs. The artificial sebocyte gland exhibited specific biological function and structure similar to natural sebocyte glands. Using this artificial sebocyte gland, the interactions between the artificial organ and blue light or UV were studied. The results indicated that UV and blue light upregulated lipid secretion and downregulated cell viability within the sebocytes. Light damage intensified oxidative stress and promoted pro-inflammation cytokines (i.e., IL-1β and TNF-α) production in the artificial sebocytes. Additionally, the therapeutic effects of cannabidiol, a clinically tested drug for treating acne, was also indicated on restoring light damaged sebaceous gland functions. These results indicate that the 3D artificial sebocyte gland could be a versatile, fast, and low-cost platform for skincare studies or drug screening.

Sun exposure, a relevant exposome factor in acne patients and how photoprotection can improve outcomes

BACKGROUND

Acne pathophysiology includes a complex interaction among inflammatory mediators, hyperseborrhea, alteration of keratinization and follicular colonization by Propionibacterium acnes.

AIMS

To describe the impact of the exposome on acne and how photoprotection can improve outcomes.

METHODS

A narrative review of the literature was carried out; searches with Google Scholar and Pubmed from January 1992 to November 2022 were performed. The keywords used were "acne," "sunscreens," "photoprotection," "cosmetics," "cosmeceuticals," "pathogenesis," "etiology," "exposome," "sunlight," "stress," "lack of sleep," "diet," "postinflammatory hyperpigmentation," "pollution," "exposome," "ultraviolet radiation," and "visible light."

RESULTS

Environmental factors such as solar radiation, air pollution, tobacco consumption, psychological stress, diverse microorganisms, nutrition, among others, can trigger or worsen acne. Solar radiation can temporarily improve lesions. However, it can induce proinflammatory and profibrotic responses, and produce post-inflammatory hyperpigmentation and/or post-inflammatory erythema. While photoprotection is widely recommended to acne patients, only four relevant studies were found. Sunscreens can significantly improve symptomatology or enhance treatment and can prevent post-inflammatory hyperpigmentation. Furthermore, they can provide camouflage and improve quality of life. Based on acne pathogenesis, optimal sunscreens should have emollient, antioxidant and sebum controlling properties.

CONCLUSIONS

The exposome and solar radiation can trigger or worsen acne. UV light can induce post-inflammatory hyperpigmentation/erythema, and can initiate flares. The use of specifically formulated sunscreens could enhance adherence to topical or systemic therapy, camouflage lesions (tinted sunscreens), decrease inflammation, and reduce the incidence of post-inflammatory hyperpigmentation/erythema.

Long-term exposure to low levels of ambient UVB are associated with a decreased risk of moderate-to-severe acne: A retrospective cohort study in college students

BACKGROUND

As a crucial component of solar radiation, the association between exposure to ambient ultraviolet (UV) radiation and acne remains unclear.

METHODS

This was a multicenter retrospective cohort study of incoming college students in five universities of China. Previous exposure (6 years prior to enrollment) to different wavelengths of ambient UVs were obtained from public repositories by linking to individual hometown addresses. Logistic models were applied to assess the relationship between ambient UV exposure and acne. Subgroup analysis was conducted by sun protection behaviors and time of daily sun exposure. Overall effect and single effect of exposure to four different wavelengths of UVs (305, 310, 324, and 380 nm) were estimated by Bayesian kernel machine regression (BKMR).

RESULTS

A total of 19,939 participants was included for analysis. Analysis in all participants showed a significant association between log-transformation levels of exposure to UV at 305 nm (log (UV 305 nm)) and acne (OR = 0.77, p = .021). The effect size was stronger in participants reporting no sun protection habit. Both UVs at 305 nm (OR = 0.51, p = .001) and 310 nm (OR = 0.50, p = .012) were associated a decreased risk of acne in participants reporting no sun protection habit. This inverse association was also observed in those exposed to low levels of UV (<1 h/day). The BKMR indicated consistent results that low levels of exposure to UVs combination and UVs at 305 and 310 nm were associated with a lower risk of acne.

CONCLUSION

Long-term exposure to relatively low levels of ambient UVB are associated with a decreased risk of moderate-to-severe acne in college students.

Active compound chrysophanol of Cassia tora seeds suppresses heat-induced lipogenesis via inactivation of JNK/p38 MAPK signaling in human sebocytes

Background

Heat induced by infrared (IR) radiation from sun exposure increases skin temperature and can lead to thermal and photo-aging. However, little is known about the relationship between heat induced by IR radiation and lipid biosynthesis in human sebocytes. This study investigated the expression of factors involved in lipid biosynthesis in human sebocytes exposed to heat. The effect of Cassia tora extract and chrysophanol, which is widely used as anti-inflammatory agent, on the heat shock effect in sebocytes was then examined.

Methods

For the treatment, cells were maintained in culture medium without FBS (i.e., serum starved) for 6 h and then moved for 30 min to incubators at 37 °C (control), 41 °C, or 44 °C (heat shock). Culture media were replaced with fresh media without FBS. To investigate expression of gene and signaling pathway, we performed western blotting. Lipid levels were assessed by Nile red staining. The cytokine levels were measured by cytokine array and ELISA kit.

Results

We found that peroxisome proliferator-activated receptor (PPAR)γ and fatty acid synthase (FAS) were upregulated and the c-Jun N-terminal kinase (JNK)/p38 signaling pathways were activated in human sebocytes following heat exposure. Treatment with Cassia tora seed extract and chrysophanol suppressed this up-regulation of PPARγ and FAS and also suppressed the increase in IL-1β levels.

Conclusion

These findings provide evidence that IR radiation can stimulate sebum production; Cassia tora seed extract and chrysophanol can reverse lipid stimulated inflammatory mediation, and may therefore be useful for treating skin disorders such as acne vulgaris.

The influence of exposome on acne

BACKGROUND

Acne vulgaris is one of the main reasons for dermatological consultations. Severity and response to treatment may be impacted by various external factors or exposome.

AIM

To assess the impact of environmental factors on acne and to provide a comprehensive overview of the acne exposome.

METHODS

Two consensus meetings of five European dermatologists and a comprehensive literature search on exposome factors triggering acne served as a basis for this review.

RESULTS

Acne exposome was defined as the sum of all environmental factors influencing the occurrence, duration and severity of acne. Exposome factors impact on the response and the frequency of relapse to treatments by interacting with the skin barrier, sebaceous gland, innate immunity and cutaneous microbiota. They may be classified into the following six main categories: nutrition, psychological and lifestyle factors, occupational factors including cosmetics, as well as pollutants, medication and climatic factors. Moreover, practical considerations for the dermatologist's clinical practice are proposed.

CONCLUSION

Exposome factors including nutrition, medication, occupational factors, pollutants, climatic factors, and psychosocial and lifestyle factors may impact on the course and severity of acne and on treatment efficacy. Identifying and reducing the impact of exposome is important for an adequate acne disease management.

Analysis of Serum Cytokine Profile in Pemphigus

BACKGROUND

Pemphigus is a group of autoimmune blistering diseases affecting skin and mucous membranes. While pemphigus is an autoantibody mediated disease, the role of T cells and cytokines in the pathogenesis is being increasingly recognized.

OBJECTIVE

This study was conducted to observe alterations in the serum cytokine levels of patients with pemphigus vulgaris (PV), pemphigus foliaceous (PF), paraneoplastic pemphigus (PNP) and compare with bullous pemphigoid (BP) and healthy subjects.

METHODS

A total of 75 subjects (28 PV, 13 PF, 7 PNP, 7 BP, and 20 healthy controls) were included, all patients in active disease state. Serum levels of interferon (IFN)-γ, interleukin (IL)-4, IL-6, IL-17A, IL-10, tumor necrosis factor (TNF)-α, and IL-8 were measured by enzyme-linked immunosorbent assay.

RESULTS

The median concentration of IFN-γ was lower in PV and BP patients compared to control (0.77, 0.34 and 1.63 pg/ml, respectively). IL-6 and IL-10 was significantly higher in PNP patients compared to control (4.92 and 0.24 pg/ml for IL-6, 0.86 and <0.12 pg/ml for IL-10, respectively). IL-8 was increased significantly in PV and PNP patients compared with control (11.85, 31.5 and 8.31 pg/ml, respectively). For IL-4, IL-17A and TNF-α, no significant difference was observed between the five groups.

CONCLUSION

The decreased level of IFN-γ in PV may imply suppressed Th1 response in the active disease stage. A Th2 predominant response is suggested in the active stage of PNP, with elevated serum levels of IL-6 and IL-10. Increased level of proinflammatory cytokine IL-8 is observed in the sera of PV and PNP patients.

Insulin-Like Growth Factor-1 Increases the Expression of Inflammatory Biomarkers and Sebum Production in Cultured Sebocytes

Background

Acne vulgaris has been linked to the Western diet. Hyperglycemic diet increases insulin and insulin-like growth factor (IGF)-1. Deeper insights into IGF-1-mediated signal pathway are critical importance to understand the impact of Western diet.

Objective

We investigated the effect of IGF-1 on the expression of inflammatory biomarkers and sebum production in cultured sebocytes.

Methods

Polymerase chain reaction and enzyme-linked immunosorbent assay were performed to measure changes in the expression of inflammatory biomarkers including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), IGF1R, IGFBP2, sterol response element-binding protein (SREBP), and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PI3KCA) after the treatment of cultured sebocytes with 10⁻⁷ M or 10⁻⁵ M IGF-1. Sebum production was evaluated after the treatment of cultured sebocytes with 10⁻⁷ M or 10⁻⁵ M IGF-1 using lipid analysis.

Results

The expression levels of IL-1β, IL-6, IL-8, and TNF-α in cultured sebocytes after treatment with 10⁻⁷ M or 10⁻⁵ M IGF-1 were increased. Increased gene expression levels of NF-κB in cultured sebocytes were also shown after 10⁻⁷ M or 10⁻⁵ M IGF-1 treatments. Gene expression of these inflammatory biomarkers was decreased after 10⁻⁷ M or 10⁻⁵ M IGF-1 treatment in the presence of 100 nM NF-κB inhibitor. Treatment with 10⁻⁷ M or 10⁻⁵ M IGF-1 increased the gene expression levels of IGF1R, IGFBP2, SREBP and PI3KCA in cultured sebocytes. Sebum production from cultured sebocytes treated with 10⁻⁷ M or 10⁻⁵ M IGF-1 was also increased.

Conclusion

It is suggestive that IGF-1 might be involved in the pathogenesis of acne by increasing both expression of inflammatory biomarkers and also sebum production in sebocytes.