Aernoud Fiolet

278 Chapter 11 Figure 5. Hs-CRP and IL-6 levels after one year treatment with colchicine or placebo. Serum hs- CRP and IL-6 levels in patients treated with colchicine compared to placebo. Boxplots represent medians with inter quartile range and whiskers show 10-90th percentile. Abbreviations: Hs-CRP, High sensitivity C-reactive Protein; IL-6, interleukin-6; NS, not significant DISCUSSION InthisLoDoCo2biomarkersubstudy,weshowedinvitrothatNLRP3inflammasome stimulation leads to an increase in EV NLRP3 protein levels. In vivo, in patients with chronic coronary disease, EV NLRP3 protein levels were lower in those treated for a year with colchicine. Lastly, colchicine leads to a reduction in hs-CRP that is not related to EV NLRP3 protein levels. In vitro NLRP3 inflammasome stimulation In vitro assays using LPS, ATP and other activators are widely used to investigate stimulation of the NLRP3 inflammasome. 6,23–26 These in vitro studies showed that NLRP3 inflammasome stimulation leads to the release of mature IL-1 β . 6,23,24 Our findings reveal that NLRP3 inflammasome stimulation in vitro also leads to higher EV NLRP3 protein levels. Since NLRP3 protein is an NLRP3 inflammasome component, this may indicate that EV NLRP3 protein levels reflect the status of the NLRP3 inflammasome in the parent cells. Stimulated NLRP3 inflammasome increases mature IL-1 β levels and colchicine has been shown to attenuate this release. 26,27 IL-1 β is also released by the activation of other inflammasomes and cleavage of intracellular pro-IL-1 β can be independent of inflammasomes. 15