Baricitinib combination therapy: a narrative review of repurposed Janus kinase inhibitor against severe SARS-CoV-2 infection.

PURPOSE: The Coronavirus disease 2019 (COVID-19) pandemic is one of the most devastating global problems. Regarding the lack of disease-specific treatments, repurposing drug therapy is currently considered a promising therapeutic approach in pandemic situations. Recently, the combination therapy of Janus kinase (JAK) inhibitor baricitinib has been authorized for emergency COVID-19 hospitalized patients; however, this strategy's safety, drug-drug interactions, and cellular signaling pathways remain a tremendous challenge. METHODS: In this study, we aimed to provide a deep insight into the baricitinib combination therapies in severe COVID-19 patients through reviewing the published literature on PubMed, Scopus, and Google scholar databases. We also focused on cellular and subcellular pathways related to the synergistic effects of baricitinib plus antiviral agents, virus entry, and cytokine storm (CS) induction. The safety and effectiveness of this strategy have also been discussed in moderate to severe forms of COVID-19 infection. RESULTS: The severity of COVID-19 is commonly associated with a dysregulated immune response and excessive release of pro-inflammatory agents, resulting in CS. It has been shown that baricitinib combined with antiviral agents could modulate the inflammatory response and provide a series of positive therapeutic outcomes in hospitalized adults and pediatric patients (age ≥ two years old). CONCLUSION: Baricitinib plus the standard of care treatment might be a potential strategy in hospitalized patients with severe COVID-19.

Immunolocalization and Expression of JAK1 and JAK3 in the Skin of Dust Mite-Sensitive Beagle Dogs before and after Allergen Exposure.

Janus kinase (JAK) pathways have emerged as targets of treatment, yet localization and expression of JAK1 and JAK3 in canine atopic skin have not been studied. This study aimed to compare the localization and expression of JAK1 and JAK3 in the skin of atopic dogs before and after allergen exposure. Skin biopsies taken from atopic beagles sensitized to house dust mites (HDM) before (D0) and after four weeks (D28) of allergen exposure were stained. Staining was subjectively scored by examiners unaware of the source of the slides. Image J was used for the semiquantitative assessment of staining intensity. JAK1 and JAK3 staining was epidermal and dermal. JAK1 staining was cytoplasmic, primarily found in basal keratinocytes and dermal cells, while JAK 3 was nuclear (all epidermal levels and on dermal inflammatory cells). Epidermal thickness was significantly higher on D28 than on D0 (p < 0.0001). For JAK1, epidermal staining divided by epithelial thickness was significantly lower on D28 (p = 0.0002) compared to D0. For JAK3 staining, intensity in the dermis was significantly higher on D28 (p = 0.0405) compared to D0. We conclude that decreased expression of JAK1 in the epidermis and increased expression of JAK3 in the dermis of atopic dogs occur after allergen exposure.

JAK-STAT inhibitors: Immersing therapeutic approach for management of rheumatoid arthritis.

Rheumatoid arthritis is a world leading cause of musculoskeletal disease. With the introduction of biological agents as treatment alternatives the clinical possibilities have grown exponentially. Currently most common Disease-modifying anti-rheumatic drugs (DMARDs) treatment option involves intravenous or subcutaneous injection, and some patients struggle to respond to DMARDs or lose their primary reaction. An oral drug formulation with lowered costs of manufacturing and flexibility for healthcare workers to preferably perform treatment will result in decreased healthcare expenditures and increased medication compliance. The JAK-STAT inhibitors, a new class of small molecules drugs, fulfills these criteria and has recently shown efficacy in rheumatoid arthritis. Here we give a summary of how JAK-STAT inhibitors function and a detailed review of current clinical trials. Convincing clinical results suggest that therapeutic inhibition of the JAK proteins can effectively modulate a complex cytokine-driven inflammation.