The skin is an important organ that acts as a physical barrier to the outer environment. It is rich in immune cells such as keratinocytes, Langerhans cells, mast cells, and T cells, which provide the ...first line of defense mechanisms against numerous pathogens by activating both the innate and adaptive response. Cutaneous immunological processes may be stimulated or suppressed by numerous plant extracts via their immunomodulatory properties. Several plants are rich in bioactive molecules; many of these exert antimicrobial, antiviral, and antifungal effects. The present study describes the impact of plant extracts on the modulation of skin immunity, and their antimicrobial effects against selected skin invaders. Plant products remain valuable counterparts to modern pharmaceuticals and may be used to alleviate numerous skin disorders, including infected wounds, herpes, and tineas.
Many recent studies have revealed the key roles played by Th1/Th2 cell dysregulation, IgE production, mast cell hyperactivity, and dendritic cell signaling in the pathogenesis of atopic dermatitis. ...Accordingly, current therapy has been largely directed towards ameliorating Th2-mediated inflammation and/or pruritus. We will review here emerging evidence that the inflammation in atopic dermatitis results from inherited and acquired insults to the barrier and the therapeutic implications of this new paradigm.
Recent molecular genetic studies have shown a strong association between mutations in FILAGGRIN and atopic dermatitis, particularly in Northern Europeans. But additional acquired stressors to the barrier are required to initiate inflammation. Sustained hapten access through a defective barrier stimulates a Th1 --> Th2 shift in immunophenotype, which in turn further aggravates the barrier. Secondary Staphylococcus aureus colonization not only amplifies inflammation but also further stresses the barrier in atopic dermatitis.
These results suggest a new 'outside-to-inside, back to outside' paradigm for the pathogenesis of atopic dermatitis. This new concept is providing impetus for the development of new categories of 'barrier repair' therapy.
Curcumin, a natural polyphenolic and yellow pigment obtained from the spice turmeric, has strong antioxidative, anti‐inflammatory, and antibacterial properties. Due to these properties, curcumin has ...been used as a remedy for the prevention and treatment of skin aging and disorders such as psoriasis, infection, acne, skin inflammation, and skin cancer. Curcumin has protective effects against skin damage caused by chronic ultraviolet B radiation. One of the challenges in maximizing the therapeutic potential of curcumin is its low bioavailability, limited aqueous solubility, and chemical instability. In this regard, the present review is focused on recent studies concerning the use of curcumin for the treatment of skin diseases, as well as offering new and efficient strategies to optimize its pharmacokinetic profile and increase its bioavailability.
Curcumin, a natural polyphenolic and yellow pigment obtained from the spice turmeric, has strong antioxidative, anti‐inflammatory, and antibacterial properties; due to these properties, curcumin has been used as a remedy for the prevention and treatment of skin aging and disorders such as psoriasis, infection, acne, skin inflammation, and skin cancer and curcumin has protective effects against skin damage caused by chronic ultraviolet B radiation. One of the challenges in maximizing the therapeutic potential of curcumin is its low bioavailability, limited aqueous solubility, and chemical instability; in this regard, the present review is focused on recent studies concerning the use of curcumin for the treatment of skin diseases, as well as offering new and efficient strategies to optimize its pharmacokinetic profile and increase its bioavailability.
Summary
Background
Human skin protects the body from external damage, pathogens and oxidative stress factors such as ultraviolet (UV) radiation. Excessive exposure to UV radiation can lead to ...increased production of free radicals and hence to skin damage such as inflammation, premature skin ageing and skin cancer. Besides UV, the visible and near infrared (NIR) regions are also a source of radical production. Half of all free radicals are induced by the visible + NIR region of the solar spectrum in people with skin types I–III, but data on the effects in people with skin types IV–VI are missing.
Objectives
This in vivo pilot study addressed the distribution of radical production in skin types IV and V during irradiation in the UV, visible and NIR spectral regions, comparing the first results with those of skin type II.
Methods
The measurements were performed in vivo using L‐band electron paramagnetic resonance spectroscopy and the spin probe PCA.
Results
In skin types IV–V most radicals were induced in the visible + NIR region, followed by the NIR and UV regions of the sun spectrum. Significantly (P ≤ 0·05) more radicals were induced in skin types IV–V than in type II during NIR irradiation, whereas skin types IV–V exhibited significantly less UV‐induced radicals (P ≤ 0·01) than skin type II.
Conclusions
All spectral regions (UV, visible and NIR) cause free radical formation in skin types II and IV–V. After 4 min of solar‐simulated exposure (UV‐NIR), the radical formation in skin types IV–V is 60% of that in skin type II. Therefore people with darker skin types also need solar protection.
What's already known about this topic?
Excessive exposure to ultraviolet (UV) radiation can lead to increased production of free radicals and hence to skin damage such as inflammation, premature skin ageing and tumour progression.
The visible and near infrared (NIR) regions of the solar spectrum also induce radicals.
Half of all free radicals in skin types I–III are due to visible + NIR exposure, but data about the effects in skin types IV–VI are missing.
What does this study add?
This in vivo pilot study addresses the distribution of radical production in skin types IV and V during irradiation in the UV, visible and NIR spectral regions, comparing the results with those of skin type II.
The results provide the first ideas of possible long‐term effects of excessive exposure to visible and NIR radiation in skin types IV and V.
What is the translational message?
In people with skin types IV–V, significantly more radicals were formed during NIR irradiation compared with skin type II.
As in skin types IV–V the NIR values reach or exceed those of the UV and visible, which could influence premature skin ageing and carcinogenesis.
Individuals with skin types IV–VI might need a different type of sun protection from those with skin types I–III to avoid subsequent damage by solar radiation.
Respond to this article
Linked Comment: Young. Br J Dermatol 2019; 180:456–457.
Plain language summary available online
Global climate is changing at an extraordinary rate. Climate change (CC) can be caused by several factors including variations in solar radiation, oceanic processes, and also human activities. The ...degree of this change and its impact on ecological, social, and economical systems have become important matters of debate worldwide, representing CC as one of the greatest challenges of the modern age. Moreover, studies based on observations and predictive models show how CC could affect human health. On the other hand, only a few studies focus on how this change may affect human skin. However, the skin is the most exposed organ to environment; therefore, it is not surprising that cutaneous diseases are inclined to have a high sensitivity to climate. The current review focuses on the effects of CC on skin diseases showing the numerous factors that are contributing to modify the incidence, clinical pattern and natural course of some dermatoses.
As an interface with the environment, the skin is a complex ecosystem colonized by many microorganisms that coexist in an established balance. The cutaneous microbiome inhibits colonization with ...pathogens, such as Staphylococcus aureus, and is a crucial component for function of the epidermal barrier. Moreover, crosstalk between commensals and the immune system is now recognized because microorganisms can modulate both innate and adaptive immune responses. Host-commensal interactions also have an effect on the developing immune system in infants and, subsequently, the occurrence of diseases, such as asthma and atopic dermatitis (AD). Later in life, the cutaneous microbiome contributes to the development and course of skin disease. Accordingly, in patients with AD, a decrease in microbiome diversity correlates with disease severity and increased colonization with pathogenic bacteria, such as S aureus. Early clinical studies suggest that topical application of commensal organisms (eg, Staphylococcus hominis or Roseomonas mucosa) reduces AD severity, which supports an important role for commensals in decreasing S aureus colonization in patients with AD. Advancing knowledge of the cutaneous microbiome and its function in modulating the course of skin disorders, such as AD, might result in novel therapeutic strategies.
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