Milakovic 2021: PDE4i in Psoriasis Flashcards
Psoriasis def
Psoriasis is a chronic immune-mediated inflammatory disorder.
PDE4i use in psoriasis
PDE-4 degrades its substrate cyclic adenosine monophosphate (cAMP) to adenosine monophosphate (AMP), which subsequently leads to the production of pro-inflammatory mediators. Inhibitors of PDE-4 work by blocking the degradation of cAMP, which leads to a reduction in inflammation.
only approved oral PDE4i for psoriasis
apremilast
topical PDE4is
crisaborole, roflumilast
crisaborole indication
atopic dermatitis
Psoriasis immunopathogenesis involves multiple inflammatory mediators, including
- tumor necrosis factor (TNF)-α
- interleukin (IL)-12
- IL-17
- IL-22
- IL-23
- interferon (IFN)-γ.
hough topical corticosteroids (TCS) are commonly used and are often effective at treating psoriatic plaques, their long-term side effects, such as X and Y limit their usage.
atrophy and striae
cAMP is activated by G-protein coupled receptor ligands which upon activation of cAMP, mediate signal transduction mainly through protein kinase A (PKA).
Next step?
PKA then activates cAMP response element-binding protein (CREB), a response element that is possessed by numerous genes involved in the pathophysiology of psoriasis, including IL-2, IL-6, IL-10 and TNFα
Intracellular cAMP concentrations are mediated by X and phosphodiesterases (PDE).
adenylyl cyclase (AC)
PDEs are responsible for degrading cAMP, of which the X isoenzyme is the most prominent in immune cells, such as lymphocytes, granulocytes and monocytes/macrophages
PDE4i
DE-4 inhibitors can therefore suppress inflammatory cytokine generation and secretion, including IFN-γ, TNF-α, and IL-2, IL-12 and IL-23,8 as well as
reduce superoxide generation and chemotaxis
As well, PDE-4 inhibitors upregulate anti-inflammatory cytokines such as IL-10 through activation of
CREB
Both non-selective and selective PDE inhibitors are available on the market for various indications. The non-selective PDE inhibitors include
pentoxifylline and theophylline; no known benefit for psoriasis
Pentoxifylline, used in peripheral vascular disease, is a competitive
non-selective PDE inhibitor
Theophylline is a mostly non-selective PDE inhibitor that has some selective inhibition of PDE1-5 and is used to
improve airflow obstruction in asthma, chronic bronchitis and chronic obstructive pulmonary disease (COPD).