Obesity and the microbiome in atopic dermatitis: Therapeutic implications for PPAR-γ agonists

Facial Physiological Characteristics and Skin Microbiomes Changes are Associated with Body Mass Index (BMI)

Background

Overweight and obesity have become public health problems worldwide. An increasing number of research works are focusing on skin physiology and the manifestations of obesity-associated skin diseases, but little is known about the correlations between body mass index (BMI), facial skin physiological parameters, and the facial skin microbiome in healthy women.

Objective

To investigate the correlations between BMI, facial skin physiological parameters and facial bacteria and fungi in 198 women aged 18 to 35 years in Shanghai.

Methods

According to the international BMI standard and Chinese reference standard, subjects were divided into three groups, "lean" B1, "normal" B2 and "overweight" B3, and the physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiota was analyzed by 16S rRNA and ITS high-throughput sequencing.

Results

Compared with the skin physiological parameters of the normal group, those of the overweight group exhibited a significant increase in trans-epidermal water loss (TEWL), which indicated that the skin barrier was impaired. The skin haemoglobin content was significantly increased, and skin surface pH was significant decreased in those with a high BMI. Furthermore, α-diversity, analysed using the Shannon, Chao, Sobs, and Ace indexes, was increased in the overweight group, suggesting that the diversity and species abundance of facial bacterial and fungal microbiota were also increased. Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia, and Candida. Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida, and Cladosporium. Besides, the abundance of Malassezia was positively associated with the abundances of Staphylococcus and Corynebacterium.

Conclusion

These results indicate that BMI is associated with differences in the biophysical properties and microbiome of the facial skin. A high BMI affects the integrity of skin barrier and changes the skin flora diversity and species composition.

Adipokines in atopic dermatitis: the link between obesity and atopic dermatitis

Atopic dermatitis (AD) is a chronic skin condition with intense pruritus, eczema, and dry skin. The recurrent intense pruritus and numerous complications in patients with AD can profoundly affect their quality of life. Obesity is one of its comorbidities that has been confirmed to be the hazard factor of AD and also worsen its severity. Nevertheless, the specific mechanisms that explain the connection between obesity and AD remain incompletely recognized. Recent studies have built hopes on various adipokines to explain this connection. Adipokines, which are disturbed by an obese state, may lead to immune system imbalances in people with AD and promote the development of the disease. This review focuses on the abnormal expression patterns of adipokines in patients with AD and their potential regulatory molecular mechanisms associated with AD. The connection between AD and obesity is elucidated through the involvement of adipokines. This conduces to the in-depth exploration of AD pathogenesis and provides a new perspective to develop therapeutic targets.

Obesity and Selected Allergic and Immunological Diseases-Etiopathogenesis, Course and Management

Obesity is a global problem. It affects every age group and is associated with many negative health effects. As an example, there is a relationship between obesity and allergic and immunological diseases, such as asthma, psoriasis, food allergies, allergic rhinitis and atopic dermatitis. Obesity undeniably affects their development. In addition, it causes adverse changes in the course and response to therapy in relation to patients without excessive body weight. The treatment of diseases associated with obesity is difficult; drugs are less effective and must be used in higher doses, and their use in patients with obesity is often associated with higher risks. The main form of treatment of all obesity-related diseases is a change in eating habits and increased physical activity, which leads to a decrease in body fat mass. The positive effect of reducing BMI has been confirmed in many independent studies. This paper reviews various types of research documents published since 2019. It aims to systematize the latest knowledge and highlight the need for further research for effective and sustainable treatment options for obesity, its complications and obesity-related diseases.