Comparison of the dietary omega-3 fatty acids impact on murine psoriasis-like skin inflammation and associated lipid dysfunction

Macrophage Functions in Psoriasis: Lessons from Mouse Models

Psoriasis is a systemic autoimmune/autoinflammatory disease that can be well studied in established mouse models. Skin-resident macrophages are classified into epidermal Langerhans cells and dermal macrophages and are involved in innate immunity, orchestration of adaptive immunity, and maintenance of tissue homeostasis due to their ability to constantly shift their phenotype and adapt to the current microenvironment. Consequently, both macrophage populations play dual roles in psoriasis. In some circumstances, pro-inflammatory activated macrophages and Langerhans cells trigger psoriatic inflammation, while in other cases their anti-inflammatory stimulation results in amelioration of the disease. These features make macrophages interesting candidates for modern therapeutic strategies. Owing to the significant progress in knowledge, our review article summarizes current achievements and indicates future research directions to better understand the function of macrophages in psoriasis.

Diet and skin health: The good and the bad

The skin protects humans from pathogens, ultraviolet light, chemicals, mechanical, thermal, and physical injuries as well as hazardous substances. Other important roles of the skin include the regulation of several important physiological processes of the body, sensing stimuli, synthesis of vitamin D, and immune surveillance. However, aging, diseases and environmental conditions significantly change the skin's behavior and functioning. The treatment and prevention strategies for various skin diseases especially photoaging usually include topical treatment with medical cosmetology, active ingredients and other physical means of photoprotection. In recent times, however, there is an increasing consciousness about the role of diet and nutrition in skin health with certain dietary components emerging as an adequate alternative approach to alleviate and prevent both endogenous and exogenous aging symptoms. Therefore, this narrative review uniquely discusses the basic structure of the skin and also addresses common dermatological signs of damaged skin, the impacts of unhealthy diet habits on the skin, and the beneficial effects of some healthy diet habits on skin health. The information and data were collated from various literature databases and resources such as Science Direct, PubMed, Wiley, Springer, Taylor and Francis, Inflibnet, Scopus, Google, and Google Scholar using relevant keywords Medical Subject Headings (MeSH). In conclusion, diet and nutrition play essential roles in the optimum functioning of the human body, including the skin. Thus, certain diet habits such as less water intake, high-fat diet, refined sugar, and certain food additives are unhealthy and harmful to the skin while alternative healthy diet habits such as adequate water intake; consumption of antioxidants and polyphenolic-rich fruits, vegetables, nuts, and legumes; a low glycemic index diet; probiotics; and phytoestrogens should be adopted to enhance skin health.

Effect of Dietary Supplementation with Omega-3 Fatty Acid on the Generation of Regulatory T Lymphocytes and on Antioxidant Parameters and Markers of Oxidative Stress in the Liver Tissue of IL-10 Knockout Mice

INTRODUCTION

chronic low-grade inflammation, or inflammaging, emerges as a crucial element in the aging process and is associated with cardiovascular and neurological diseases, sarcopenia, and malnutrition. Evidence suggests that omega-3 fatty acids present a potential therapeutic agent in the prevention and treatment of inflammatory diseases, mitigating oxidative stress, and improving muscle mass, attributes that are particularly relevant in the context of aging. The objective of the present study was to evaluate the effectiveness of supplementation with omega-3 fish oil in improving the immune response and oxidative stress in knockout mice for interleukin IL-10 (IL-10-/-).

MATERIAL AND METHODS

female C57BL/6 wild-type (WT) and interleukin IL-10 knockout (IL-10-/-) mice were fed during 90 days with a standard diet (control groups), or they were fed/supplemented with 10% of the omega-3 polyunsaturated fatty acid diet (omega-3 groups). Muscle, liver, intestinal, and mesenteric lymph node tissue were collected for analysis.

RESULTS

the IL-10-/-+O3 group showed greater weight gain compared to the WT+O3 (p = 0.001) group. The IL-10-/-+O3 group exhibited a higher frequency of regulatory T cells than the IL-10-/- group (p = 0.001). It was found that animals in the IL-10-/-+O3 group had lower levels of steatosis when compared to the IL-10-/- group (p = 0.017). There was even greater vitamin E activity in the WT group compared to the IL-10-/-+O3 group (p = 0.001) and WT+O3 compared to IL-10-/-+O3 (p = 0.002), and when analyzing the marker of oxidative stress, MDA, an increase in lipid peroxidation was found in the IL-10-/-+O3 group when compared to the IL-10-/- group (p = 0.03). Muscle tissue histology showed decreased muscle fibers in the IL-10-/-+O3, IL-10-/-, and WT+O3 groups.

CONCLUSION

the findings show a decrease in inflammation, an increase in oxidative stress markers, and a decrease in antioxidant markers in the IL-10-/-+O3 group, suggesting that supplementation with omega-3 fish oil might be a potential intervention for inflammaging that characterizes the aging process and age-related diseases.

Causality of unsaturated fatty acids and psoriasis a Mendelian randomization study

Background

Many observational studies have identified a link between unsaturated fatty acids and psoriasis. However, they contain reverse causality and confounding factors, and there is no definite causal study between unsaturated fatty acids and psoriasis.

Objectives

Analysis of causality between unsaturated fatty acids and psoriasis by Mendelian randomization.

Methods

We used IEU Open GWAS Project, omega-3 PUFA and omega-6 PUFA data from 114,999 subjects, MUFA data from 13,535 subjects, and psoriasis data from 4,510 cases and 212,242 controls were included. We employed the inverse-variance weighted (IVW) method as the primary analytical approach and four additional MR methods. Moreover, we performed heterogeneity and horizontal pleiotropy assessments using Cochrane's Q and MR-Egger intercept tests, respectively. Finally, we performed sensitivity analyses to enhance our findings' precision and veracity.

Results

IVW results showed no causal effect of omega-3 PUFA on psoriasis (p = 0.334; OR, 0.909; 95% CI, 0.748-1.104), omega-6 PUFA cause psoriasis (p = 0.046; OR, 1.174; 95% CI, 1.003-1.374), MUFA cause psoriasis (p = 0.032; OR, 1.218; 95% CI, 1.018-1.457), no causal effect of omega-3 PUFA in psoriasis (p = 0.695; OR, 0.989; 95% CI, 0.937-1.044), no causal effect of omega-6 PUFA in psoriasis (p = 0.643; OR, 1.013; 95% CI, 0.960-1.068), psoriasis is not causal to MUFA (p = 0.986; OR, 1.000; 95% CI, 0.949-1.055). Heterogeneity, horizontal pleiotropy, and sensitivity analyses showed reliable results.

Conclusion

We found that circulating omega-6 PUFA and MUFA cause psoriasis, while omega-3 PUFA do not. Treatments that lower circulating omega-6 PUFA and MUFA are effective in psoriasis. After a better understanding of fatty acid intake and circulation, the population can be advised to regulate their diet.

Nutraceutical combination ameliorates imiquimod-induced psoriasis in mice

Psoriasis is a chronic inflammatory skin disease that affects both localized and systemic regions of the body. This condition is characterized by the hyperproliferation of keratinocytes, resulting in skin thickening, scaling, and erythema. The severity of psoriasis depends on the extent of skin involvement, the location of the infection, and the symptoms that the person exhibits. While no cure exists, conventional therapies such as topical and systemic drugs are generally used to manage the exacerbation of symptoms. However, chronic use and overdose can lead to other severe adverse effects. Therefore, scientists and researchers are exploring potential nutraceuticals that can be considered as an alternative source of management for psoriasis. Current research aims to use different combinations of natural compounds like cannabidiol, myo-inositol, eicosapentaenoic acid, and krill oil to study the effect of these compounds in the prevention and treatment of psoriasis in the imiquimod (IMQ)-induced psoriatic mice model. The Psoriasis Area Severity Index (PASI) scoring system is used to analyze skin thickness, scales, and erythema. The results indicate that the krill oil combined with the cannabidiol and myo-inositol shows better results than other nutraceutical combinations. In the future, the natural products of krill oil can be combined with cannabidiol and myo-inositol to create an improved alternative to existing steroidal and nonsteroidal anti-inflammatory drugs for psoriasis treatment.

Lysophospholipase D from Thermocrispum limits psoriatic inflammation by hydrolyzing epidermal lysoplasmalogen produced by group IIF secreted phospholipase A2

Epidermal lipids play important roles in skin homeostasis and diseases. Psoriasis is an inflammatory disease characterized by keratinocyte hyperproliferation and Th17 immune responses. We previously reported that ethanolamine-type lysoplasmalogen (P-LPE), preferentially produced by group IIF secreted PLA2 (sPLA2-IIF/PLA2G2F) that is expressed in the suprabasal epidermis, promotes epidermal hyperplasia in psoriatic inflammation. Herein, we show that forcible degradation of epidermal P-LPE by topical application of recombinant lysophospholipase D (LyPls-PLD) from Thermocrispum, a lysoplasmalogen-specific hydrolase, attenuated epidermal hyperplasia and inflammation in imiquimod-induced and K5.Stat3C-transgenic mouse psoriasis models. In humans, P-LPE levels were elevated in the tape-stripped stratum corneum of patients with psoriasis. Moreover, in primary cultured human epidermal keratinocytes, aberrant cell proliferation and activation by psoriatic cytokines were sPLA2-IIF/P-LPE-dependent and were suppressed by the addition of LyPls-PLD with a decrease in P-LPE. These findings confirm that the sPLA2-IIF/P-LPE axis in the epidermis indeed regulates psoriasis, that P-LPE is a lipid biomarker that predicts the severity of psoriasis, and that pharmacological removal of this bioactive lipid is useful to prevent the disease. Thus, our study may lead to the development of drug discovery and diagnostic techniques based on this pathway.

Omega-3 Lipid Mediators: Modulation of the M1/M2 Macrophage Phenotype and Its Protective Role in Chronic Liver Diseases

The complex interplay between dietary factors, inflammation, and macrophage polarization is pivotal in the pathogenesis and progression of chronic liver diseases (CLDs). Omega-3 fatty acids (FAs) have brought in attention due to their potential to modulate inflammation and exert protective effects in various pathological conditions. Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown promise in mitigating inflammation and enhancing the resolution of inflammatory responses. They influence the M1/M2 macrophage phenotype balance, promoting a shift towards the M2 anti-inflammatory phenotype. Specialized pro-resolving mediators (SPMs), such as resolvins (Rvs), protectins (PDs), and maresins (MaRs), have emerged as potent regulators of inflammation and macrophage polarization. They show anti-inflammatory and pro-resolving properties, by modulating the expression of cytokines, facilitate the phagocytosis of apoptotic cells, and promote tissue repair. MaR1, in particular, has demonstrated significant hepatoprotective effects by promoting M2 macrophage polarization, reducing oxidative stress, and inhibiting key inflammatory pathways such as NF-κB. In the context of CLDs, such as nonalcoholic fatty liver disease (NAFLD) and cirrhosis, omega-3s and their SPMs have shown promise in attenuating liver injury, promoting tissue regeneration, and modulating macrophage phenotypes. The aim of this article was to analyze the emerging role of omega-3 FAs and their SPMs in the context of macrophage polarization, with special interest in the mechanisms underlying their effects and their interactions with other cell types within the liver microenvironment, focused on CLDs and the development of novel therapeutic strategies.

Eicosapentaenoic Acid Influences the Lipid Profile of an In Vitro Psoriatic Skin Model Produced with T Cells

Psoriasis is a skin disease characterized by epidermal hyperplasia and an inappropriate activation of the adaptive immunity. A dysregulation of the skin's lipid mediators is reported in the disease with a predominance of the inflammatory cascade derived from n-6 polyunsaturated fatty acids (n-6 PUFAs). Bioactive lipid mediators derived from arachidonic acid (AA) are involved in the inflammatory functions of T cells in psoriasis, whereas n-3 PUFAs' derivatives are anti-inflammatory metabolites. Here, we sought to evaluate the influence of a supplementation of the culture media with eicosapentaenoic acid (EPA) on the lipid profile of a psoriatic skin model produced with polarized T cells. Healthy and psoriatic skin substitutes were produced following the auto-assembly technique. Psoriatic skin substitutes produced with or without T cells presented increased epidermal and dermal linolenic acid (LA) and AA levels. N-6 PUFA lipid mediators were strongly measured in psoriatic substitutes, namely, 13-hydroxyoctadecadienoic acid (13-HODE), prostaglandin E2 (PGE2) and 12-hydroxyeicosatetraenoic acid (12-HETE). The added EPA elevated the amounts of EPA, n-3 docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) in the epidermal and dermal phospholipids. The EPA supplementation balanced the production of epidermal lipid mediators, with an increase in prostaglandin E3 (PGE3), 12-hydroxyeicosapentaenoic acid (12-HEPE) and N-eicosapentaenoyl-ethanolamine (EPEA) levels. These findings show that EPA modulates the lipid composition of psoriatic skin substitutes by encouraging the return to a cutaneous homeostatic state.