Applications of Ex Vivo Skin Models

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ex vivo skin model
ex vivo skin model

Ex vivo skin explants are the most accurate experimental model for healthy and pathological skin physiology. This model has keratinocytes, melanocytes, and Langerhans cells, as well as a dermal matrix of fibroblasts, collagen, elastin, and glycosaminoglycans. The prospects for using human belly hAec models and hSec models to research the physiology of the dermis and epidermis, the immunological response, skin permeability, and the effects of sun exposure on human skin and scalp are described in the ex vivo skin model sections. 

Atopic Dermatitis

 Children are most frequently affected by AD, a chronic inflammatory skin illness that causes severe pruritus and harms the quality of life. Along with many kinds of topical medications, the therapy for AD necessitates the frequent application of emollients to soften and moisturize the skin.

Although the pathophysiology of AD is not fully understood, it appears that a combination of compromised skin barrier function, immunological abnormalities, and viral and environmental factors causes the condition.

The most notable shift in the stratum corneum’s lipid profile among the epidermal barrier changes is the decrease in sphingomyelin synthase and ceramide levels and the decreased production of the envelope proteins filaggrin, involucrin, and loricrin.

  Cutaneous Permeation

 The biological effects of the active chemicals employed in the treatment of the various types of dermatosis are felt in the deeper tissues of the skin. They must penetrate the stratum corneum to accomplish this. Skin penetration is undesirable for some compounds, such as sunscreens and insect repellents, due to safety concerns.

Organization for Economic Co-operation and Development Test Guideline outlines the general guidelines for assessing dermal absorption and the degree of delivery of target molecules using mammalian skin explants, including those of human origin. It describes the validated method for evaluating ex vivo skin model permeation. 

 This test involves applying the test substance to the skin’s surface while inside the diffusion equipment. The components in the receiver compartment are then analyzed using high-performance liquid chromatography or other analytical methods to determine the degree of permeation.

 Hair Follicles

 The complex process of HF damage is regulated by historical and environmental factors. Notably, UV radiation induces oxidative stress, producing free radicals that can harm the structures found in the HF and hair fiber. 

 The skin’s HF, a little organ specializing in hair growth, relies on local stem cells to maintain the hair structure’s cyclical growth. It is generally known that as mammals’ age, they lose hair fibers and HFs due to the HFs becoming smaller and the dermal depth decreasing. These findings show that the aging of the HFSCs orchestrates the tissue aging process. Collagen XVIIA1 proteolysis initiates this process, which involves several cell types in the vicinity of the HF. Once started, it advances gradually, altering the structure of the HFs and causing depigmentation and hair loss. 

Parting Thoughts

To better understand the mechanisms underlying cutaneous illnesses and the effects of topically applied items, A test method using ex vivo skin model explants of standardized thickness and size cultivated at the air-liquid interface has been developed. It also emphasizes the possibility of later validating this model for application in regulatory safety testing.