High-fat diet induces a predisposition to follicular hyperkeratosis and neutrophilic folliculitis in mice

Evaluating dietary considerations in hidradenitis suppurativa: a critical examination of existing knowledge

Hidradenitis suppurativa (HS) is a chronic condition that can overwhelm patients, and the effectiveness of supplementary dietary treatments remains uncertain. The primary aim of this review is to explore the connection between diet and HS progression. However, it is imperative to note that the evidence supporting a substantial role of the diet in HS remains weak. Dietary alterations alone should not be considered independent solutions for managing HS. Medical therapy continues to be indispensable for adequate treatment. Research indicates that the Mediterranean lifestyle and diet may provide cost-effective and beneficial adjustments when combined with traditional therapies. Conversely, foods with a high glycemic index and dairy could worsen HS symptoms, conceivably through mechanisms linked to insulin resistance and inflammation. Zinc, known for its antioxidant properties, shows promise as an adjunct therapy. Moreover, evidence suggests a connection between vitamin D deficiency and HS severity, although the findings are inconclusive. Brewer's yeast-free diet, B12 supplementation, intermittent fasting, and reducing the intake of refined sugar and dairy merit further investigation. In conclusion, this review highlights the need for additional research because of the lack of standardized reporting of clinical effects in the studies under scrutiny. A deeper exploration of the pathophysiology focusing on dietary modifications and their potential associations with HS severity is essential. Furthermore, it is crucial to recognize that patients' willingness to experiment with new diets makes them vulnerable to fraudulent interventions, highlighting the importance of evidence-based dietary guidance.

CD36-SREBP1 Axis Mediates TSLP Production in Obesity-Exacerbated Atopic Dermatitis

Obesity is associated with an increased risk of atopic dermatitis (AD) and may accelerate its development. Keratinocyte dysfunction has been observed in obesity-related skin diseases, including psoriasis and acanthosis nigricans, but is not fully understood in AD. In this study, we found that high-fat diet-induced obesity exacerbated AD-like dermatitis in mice, with elevated inflammatory molecules and increased CD36-SREBP1-related fatty acid accumulation in the lesional skin. Blocking CD36 or SREBP1 with chemical inhibitors effectively alleviated AD-like inflammation, decreased fatty acid accumulation, and downregulated TSLP expression in obese calcipotriol (MC903)-treated mice. Moreover, palmitic acid treatment induced TSLP overexpression in keratinocytes through the activation of the CD36-SREBP1 signaling pathway. The chromatin immunoprecipitation assay further revealed increased binding of SREBP1 to the TSLP promoter region. Our findings provide compelling evidence that obesity triggers the activation of the CD36-SREBP1-TSLP axis in keratinocytes, leading to epidermal lipid disorders and the aggravation of AD-like inflammation. By targeting CD36 or SREBP1, future combination therapies or modified treatment strategies could be developed to help manage patients with both obesity and AD.

Inflammatory loops in the epithelial-immune microenvironment of the skin and skin appendages in chronic inflammatory diseases

The epithelial-immune microenvironment (EIME) of epithelial tissues has five common elements: (1) microbial flora, (2) barrier, (3) epithelial cells, (4) immune cells, and (5) peripheral nerve endings. EIME provides both constant defense and situation-specific protective responses through three-layered mechanisms comprising barriers, innate immunity, and acquired immunity. The skin is one of the largest organs in the host defense system. The interactions between the five EIME elements of the skin protect against external dangers from the environment. This dysregulation can result in the generation of inflammatory loops in chronic inflammatory skin diseases. Here, we propose an understanding of EIME in chronic skin diseases, such as atopic dermatitis, psoriasis, systemic lupus erythematosus, alopecia areata, and acne vulgaris. We discuss the current treatment strategies targeting their inflammatory loops and propose possible therapeutic targets in the future.

Exploring the roles of prostanoids, leukotriens, and dietary fatty acids in cutaneous inflammatory diseases: Insights from pharmacological and genetic approaches

Prostanoids and leukotrienes (LTs) are representative of ω6 fatty acid-derived metabolites that exert their actions through specific receptors on the cell surface. These lipid mediators, being unstable in vivo, act locally at their production sites; thus, their physiological functions remain unclear. However, recent pharmacological and genetic approaches using experimental murine models have provided significant insights into the roles of these lipid mediators in various pathophysiological conditions, including cutaneous inflammatory diseases. These lipid mediators act not only through signaling by themselves but also by potentiating the signaling of other chemical mediators, such as cytokines and chemokines. For instance, prostaglandin E2 -EP4 and LTB4 -BLT1 signaling on cutaneous dendritic cells substantially facilitate their chemokine-induced migration ability into the skin and play critical roles in the priming and/or activation of antigen-specific effector T cells in the skin. In addition to these ω6 fatty acid-derived metabolites, various ω3 fatty acid-derived metabolites regulate skin immune cell functions, and some exert potent anti-inflammatory functions. Lipid mediators act as modulators of cutaneous immune responses, and manipulating the signaling from lipid mediators has the potential as a novel therapeutic approach for human skin diseases.

Obesity and Dyslipidemia Synergistically Exacerbate Psoriatic Skin Inflammation

Patients with psoriasis are frequently complicated with metabolic syndrome; however, it is not fully understood how obesity and dyslipidemia contribute to the pathogenesis of psoriasis. To investigate the mechanisms by which obesity and dyslipidemia exacerbate psoriasis using murine models and neonatal human epidermal keratinocytes (NHEKs), we used wild-type and Apoe-deficient dyslipidemic mice, and administered a high-fat diet for 10 weeks to induce obesity. Imiquimod was applied to the ear for 5 days to induce psoriatic dermatitis. To examine the innate immune responses of NHEKs, we cultured and stimulated NHEKs using IL-17A, TNF-α, palmitic acid, and leptin. We found that obesity and dyslipidemia synergistically aggravated psoriatic dermatitis associated with increased gene expression of pro-inflammatory cytokines and chemokines. Treatment of NHEKs with palmitic acid and leptin amplified pro-inflammatory responses in combination with TNF-α and IL-17A. Additionally, pretreatment with palmitic acid and leptin enhanced IL-17A-mediated c-Jun N-terminal kinase phosphorylation. These results revealed that obesity and dyslipidemia synergistically exacerbate psoriatic skin inflammation, and that metabolic-disorder-associated inflammatory factors, palmitic acid, and leptin augment the activation of epidermal keratinocytes. Our results emphasize that management of concomitant metabolic disorders is essential for preventing disease exacerbation in patients with psoriasis.

Insights into hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, debilitating, inflammatory skin disorder with a prevalence of around 1% and a profound impact on patients' quality of life. Characteristic lesions such as inflammatory nodules, abscesses, and sinus tracts develop in the axillae, inguinal, and gluteal areas, typically during or after puberty. A complex interplay of genetic predisposition, hormonal factors, obesity, and smoking contributes to development and maintenance of the disease. HS is considered to arise from an intrinsic defect within the hair follicle, leading to follicular plugging, cyst formation, and subsequent rupture that in turn induce an acute inflammatory response characterized by elevated levels of IL-1β, IL-17, and TNF. Over time, acute lesions transition into chronic disease, with active draining sinus tracts accompanied by extensive fibrosis. HS is associated with other immune-mediated inflammatory diseases, metabolic and cardiovascular disorders, and psychiatric comorbidities. Treatment of HS often requires a combination of antibiotic or immunosuppressing therapies and surgical intervention. Nonetheless, the currently available treatments are not universally effective, and many drugs, which are often repurposed from other inflammatory diseases, are under investigation. Studies into the early stages of HS may yield treatments to prevent disease progression; yet, they are hampered by a lack of appropriate in vitro and animal models.

Role of nutritional supplements in selected dermatological disorders: A review

BACKGROUND

While a plethora of literature continues to be published on the role of nutritional agents both in lay press and indexed journals, the data is not on a firm footing and leaves the dermatologist in a quandry and the patient confused. The various agents include vitamins, minerals, amino acids, antioxidants, diets & gluten. A proper knowledge of the role of nutritional supplements in dermatological diseases can be a useful tool in advising the patients and in certain cases ameliorating the disorder.

PATIENTS/METHODS

Literature review of last 15 years was made using the terms "diet in dermatology," "nutrition and skin," "nutritional supplements in dermatology," "nutritional agents and acne," "nutritional agents and alopecia," and "nutritional agents and psoriasis."

RESULTS

While there are multiple publications on the use of nutritional supplements for amelioration of skin diseases, most of them are based on either associations or in vitro studies, but very few transcend the rigors of a clinical trial or the holey grail of a double-blinded randomized controlled trial. There seem to be some evidence in acne, psoriasis, telogen effluvium, urticaria & vitiligo. Coeliac disease and dermatitis herpetiformis have a strong link with diet. Rosacea has a strong link with certain foods, but the other disorders like melasma, aphthous stomatitis do not have any scientifically validated association with diet.

CONCLUSIONS

Our updated review examines the role of nutritional supplements and antioxidants in various dermatological disorders. We have found that there are varying levels of evidence with notable associations of low glycemic diet & acne, fish oil & weight loss with psoriasis, fish oils & probiotics with atopic dermatitis & vitamins & botanical extracts with vitiligo. The evidence for diet and nutrition in bullous disorders and photoageing is scarce. The role of low histamine diet in urticaria is useful in select cases of episodic urticaria. Rosacea is triggered by hot and spicy food . Apart from gluten and Dermatitis Herpetiformis, no diet can be considered disease modifying in our reveiw. The lack of comparison of nutritional or dietary modiffication with conventional validated agents, makes the data difficult to translate in real world patient management.