Ex vivo culture of lesional psoriasis skin for pharmacological testing

Preclinical techniques for drug discovery in psoriasis

Psoriasis is a chronic, inflammatory, papulosquamous, noncontagious disease characterized by scaly, demarcated erythematous plaque, affecting skin, nails, and scalp. The IL-23/Th17 axis is the main operator in the development of psoriasis. Psoriasis is affecting worldwide, and new treatment options are urgently needed. Various local and systemic treatments are available for psoriasis but they only provide symptomatic relief because of numerous unknown mechanisms. Clinical trials demand overwhelming resources; therefore, drug development predominantly depends on the in-vivo, in-vitro, and ex-vivo techniques. Immediate attention is required to develop experimental techniques that completely imitate human psoriasis to assist drug development. This review portrays the various in-vivo, in-vitro, and ex-vivo techniques used in psoriasis research. It describes these techniques' characteristics, pathological presentations, and mechanisms. The experimental techniques of psoriasis provide significant information on disease progression mechanisms and possible therapeutic targets. However, until now, it has been challenging to invent a timely, affordable model that precisely imitates a human disease. Only the xenotransplantation model is reckoned as the closer, that mimics the complete genetic, and immunopathogenic event. Imiquimod-induced psoriasis and HaCat cell lines are popular among researchers because of their convenience, ease of use, and cost-effectiveness. There need to further improve the experimental techniques to best serve the disease imitation and meet the research goal.

Melatonin Attenuates Imiquimod-Induced Psoriasis-Like Inflammation and Restores the Th17/Treg Immune Balance

Psoriasis is a common immune-mediated skin disease characterized by abnormally reactive inflammation and epidermal hyperplasia. Previous studies have shown melatonin (MLT) has powerful anti-inflammatory effects. The mechanisms that MLT regulates psoriasis-associated skin inflammation remain unclear. Here, in imiquimod-induced psoriasis-like mice, MLT supplementation reduced skin inflammation and corrected the Th17/Treg cell imbalance. Network pharmacology and proteome sequencing analyses revealed that MLT attenuates the inflammatory response in the skin of psoriatic mice by inhibiting the PI3K/Akt signaling pathway. Overall, the data suggest that MLT has a protective effect against psoriasis-like inflammation.

Recreating Human Skin In Vitro: Should the Microbiota Be Taken into Account?

Skin plays crucial roles in the human body: besides protecting the organism from external threats, it acts as a thermal regulator, is responsible for the sense of touch, hosts microbial communities (the skin microbiota) involved in preventing the invasion of foreign pathogens, contains immunocompetent cells that maintain a healthy immunogenic/tolerogenic balance, and is a suitable route for drug administration. In the skin, four defense levels can be identified: besides the physical, chemical, and immune barriers that are inherent to the tissue, the skin microbiota (i.e., the numerous microorganisms living on the skin surface) provides an additional barrier. Studying the skin barrier function or the effects of drugs or cosmetic agents on human skin is a difficult task since snapshot evidence can only be obtained using bioptic samples where dynamic processes cannot properly be followed. To overcome these limitations, many different in vitro models of human skin have been developed that are characterized by diverse levels of complexity in terms of chemical, structural, and cellular composition. The aim of this review is to summarize and discuss the advantages and disadvantages of the different human skin models so far available and to underline how the insertion of a proper microbiota would positively impact an in vitro human skin model in an attempt to better mimic conditions in vivo.

Inhibition of vascular endothelial growth factor-A downregulates angiogenesis in psoriasis: A pilot study

Background

Vascular Endothelial Growth Factor (VEGF)-A-mediated angiogenesis participates in the pathogenesis of psoriasis, thus inviting the hypothesis that anti-VEGF-A therapy could be beneficial in psoriasis. While anti-angiogenic agents are used in oncology and ophthalmology, these therapeutic strategies remain unexplored for the management of psoriasis.

Objective

Our objective was to investigate ex vivo how VEGF-A blockade impacts blood vessels, epidermis and immune cells in organ-cultured plaque and non-lesional skin from patients with psoriasis.

Methods

Skin biopsies from patients with psoriasis (n = 6; plaque and non-lesional skin) and healthy controls (n = 6) were incubated with anti-VEGF-A monoclonal antibody (bevacizumab, Avastin®) or a human IgG1 isotype control for 72-h in serum-free organ culture. CD31/LYVE-1, Ki-67, and mast cell tryptase expression were assessed by quantitative immunohistomorphometry. VEGF-A levels in plasma, PBMCs and skin culture supernatants were measured.

Results

Inhibition of VEGF-A blocked all free VEGF-A ex vivo, reduced blood vessel area and the number of blood vessel endothelial cells in plaques of psoriasis (*p < 0.05). The treatment effect correlated significantly with levels of VEGF-A in organ culture supernatants (r = 0.94; *p < 0.05) from plaque skin and with plasma levels of VEGF-A from patients with psoriasis (r = 0.943; *p = 0.017).

Conclusions

These ex vivo data are the first studies to objectively investigate the potential of VEGF-A inhibition as a novel adjuvant treatment strategy for psoriasis. Taken together, our data encourage further investigation by clinical trial to explore whether downregulating pathological angiogenesis has clinical utility, especially in patients with severe psoriasis or those with elevated levels of VEGF-A in plasma and/or skin.

Effect of Systemic Administration of CD4+ T cells and Local Administration of T-cell Stimulants on T-cell Activity in Psoriatic Skin Xenografts on NOG Mice

Immunodeficient mice engrafted with psoriatic human skin are widely used for the preclinical evaluation of new drug candidates. However, the T-cell activity, including the IL23/IL17 pathway, declines in the graft over time after engraftment, which likely affects the study data. Here, we investigated whether the T-cell activity could be sustained in xenografted psoriatic skin by local stimulation of T cells or systemic injection of autologous CD4 + T cells. We surgically transplanted human psoriatic skin from 5 untreated patients onto female NOG mice. Six days after surgery, mice received an intraperitoneal injection of autologous human CD4+ T cells, a subcutaneous injection under the grafts of a T-cell stimulation cocktail consisting of recombinant human IL2, human IL23, antihuman CD3, and antihuman CD28, or saline. Mice were euthanized 21 d after surgery and spleens and graft biopsies were collected for analysis. Human T cells were present in the grafts, and 60% of the grafts maintained the psoriatic phenotype. However, neither local T-cell stimulation nor systemic injection of autologous CD4+ T cells affected the protein levels of human IL17A, IL22, IFN γ, and TNF α in the grafts. In conclusion, NOG mice seem to accept psoriatic skin grafts, but the 2 approaches studied here did not affect human T-cell activity in the grafts. Therefore, NOG mice do not appear in this regard to be superior to other immunodeficient mice used for psoriasis xenografts.

Proteomic and Metabolomic Changes in Psoriasis Preclinical and Clinical Aspects

Skin diseases such as psoriasis (Ps) and psoriatic arthritis (PsA) are immune-mediated inflammatory diseases. Overlap of autoinflammatory and autoimmune conditions hinders diagnoses and identifying personalized patient treatments due to different psoriasis subtypes and the lack of verified biomarkers. Recently, proteomics and metabolomics have been intensively investigated in a broad range of skin diseases with the main purpose of identifying proteins and small molecules involved in the pathogenesis and development of the disease. This review discusses proteomics and metabolomics strategies and their utility in research and clinical practice in psoriasis and psoriasis arthritis. We summarize the studies, from in vivo models conducted on animals through academic research to clinical trials, and highlight their contribution to the discovery of biomarkers and targets for biological drugs.

Preclinical study models of psoriasis: State-of-the-art techniques for testing pharmaceutical products in animal and nonanimal models

Local and systemic treatments exist for psoriasis, but none can do more than control its symptoms because of its numerous unknown mechanisms. The lack of validated testing models or a defined psoriatic phenotypic profile hinders antipsoriatic drug development. Despite their intricacy, immune-mediated diseases have no improved and precise treatment. The treatment actions may now be predicted for psoriasis and other chronic hyperproliferative skin illnesses using animal models. Their findings confirmed that a psoriasis animal model could mimic a few disease conditions. However, their ethical approval concerns and inability to resemble human psoriasis rightly offer to look for more alternatives. Hence, in this article, we have reported various cutting-edge techniques for the preclinical testing of pharmaceutical products for the treatment of psoriasis.

Basic Quality Controls Used in Skin Tissue Engineering

Reconstruction of skin defects is often a challenging effort due to the currently limited reconstructive options. In this sense, tissue engineering has emerged as a possible alternative to replace or repair diseased or damaged tissues from the patient's own cells. A substantial number of tissue-engineered skin substitutes (TESSs) have been conceived and evaluated in vitro and in vivo showing promising results in the preclinical stage. However, only a few constructs have been used in the clinic. The lack of standardization in evaluation methods employed may in part be responsible for this discrepancy. This review covers the most well-known and up-to-date methods for evaluating the optimization of new TESSs and orientative guidelines for the evaluation of TESSs are proposed.