Effects of azathioprine and its metabolites on inflammatory cytokines in human nasal polyp organ cultures

Abstract

BackgroundOral steroids are recommended for the treatment of nasal polyps (NPs), but prolonged use is avoided because of side effects. Topical steroids can also control NPs without significant complications; however, the response to this is partially successful, and additional therapies are needed to treat glucocorticoid‐resistant NPs. Azathioprine (AZA) and its first metabolite 6‐mercaptopurine (6‐MP) are important immunosuppressants used for the therapy of various diseases. The aim of this study was to investigate the effects of AZA and 6‐MP on inflammatory cytokines in organ‐cultured NPs.MethodsNP explants were cultured using an air‐liquid interface method. Cultures were maintained in the absence and presence of steroid, AZA, and 6‐MP for 72 hours. Elaboration of cytokines tumor necrosis factor alpha (TNF‐α), interleukin (IL)‐2, IL‐4, IL‐5, and IL‐13 into the supernatant was quantitated using the enzyme‐linked immunosorbent assay (ELISA). The messenger RNA (mRNA) expression levels of TNF‐α, IL‐2, IL‐4, IL‐5, and IL‐13 in cultured mucosa were measured using real‐time polymerase chain reaction. Hematoxylin and eosin staining of cultured mucosa was performed to observe inflammatory cells. Immunohistochemistry was done to evaluate the distribution pattern of inflammatory cytokines in NP explants.ResultsOn histologic examination, less inflammatory cell infiltration was found in NPs treated by steroid, AZA, and 6‐MP than in control, but there was no statistical significance (p = 0.218). On immunohistochemistry, IL‐13 showed a steady falling tendency in submucosal glands by steroid, AZA, and 6‐MP. Expression of TNF‐α, IL‐2, IL‐4, IL‐5, and IL‐13 mRNA in the NPs treated by steroid, AZA, and 6‐MP were significantly lower than those of the control (p < 0.001 for all). By ELISA, IL‐2 and IL‐13 were significantly lower with topical steroid, AZA, and 6‐MP treatment (p = 0.012 and p < 0.001).ConclusionTopical AZT decreases inflammatory cytokines on human NP explants and this could have future therapeutic implications for NPs.

In vitro Anti-inflammatory Evaluation of 6-Thioguanine and 6-Hydroxy-2-Mercaptopurine as A Potential Treatment for Rheumatoid Arthritis

“…6-MP treatment on chronic rhinosinusitis (CRS) with nasal polyps (NPs) also exhibit lower expression of TNF-α in mRNA level. (28) The 6TG significantly is effective to decrease the IL-6 generation in colon. (29) The immunosuppressive action of 6TG may be associated to the acute inhibition of cytokine stimulation.…”

“…(27) Hence it also decreases the level of IL-1β in this study, which also could increase Rac1 action. (28) The 6-Mercaptopurine is powerful to decrease the PMA-induced expression of assorted pro-inflammatory cytokines in human NCI-H292 mucoepidermoid carcinoma and mouse lung epithelial MLE-12 cells. (10) It decreases Rac1 activity in MLE-12 cells, thus this might be the same activity pathway involved in this study by using PMAinduced synovial fibroblast cells, HIG-82.…”

Dupilumab‐induced psoriasiform dermatitis in two pediatric cardiac transplant patients

“…It is considered broadly immunosuppressive because it impedes leukocyte proliferation and migration; however, studies of the cytokine milieu after azathioprine administration demonstrate some specificity, with suppression of TNF-a, IL-2, IL-4, IL-5, and IL-13. 11,12 This profile favors Th2 inhibition given reduction of IL-4, IL-5, and IL-13. Due to this preferential Th2 cytokine inhibition, like that of dupilumab, azathioprine has been used as an effective option to treat severe AD refractory to other biologic agents.…”

Adults with inflammatory bowel disease are at a greater risk of developing chronic rhinosinusitis: A nationwide population‐based study

“…For example, methotrexate (MTX) promotes apoptosis in nasal polyps via caspase cascade and both mitochondria‐mediated and p38 MAPK/JNK pathways, 47 FAS pathway, 48 local regulation of VEGF/Ang‐1/Ang‐2 49 and local regulation of nasal polyp's chitinolytic activity 50 . Similarly, evidence shows that azathioprine can decrease inflammatory cytokines in human nasal polyps, 51 but limited only to topical use. Contrarily, both drugs do not promote the development of sinusitis, with limited evidence supporting their use as treatment for nasal polyps.…”