Geniposide Stabilized Atherosclerosis Plaque by Induced M2 Polarization via PPARγ Signaling Pathway [Letter]

Stabilized Atherosclerosis Plaque by Induced M2 Polarization via PPAR Signaling Pathway" in Drug Design, Development and Therapy. 1 Through in vivo and in vitro experiments, the authors show that Geniposide (Gen) stabilizes atherosclerotic plaques by promoting macrophage M2 polarization via activation of the PPAR signaling pathway.These findings offer valuable, albeit preliminary, insights into the anti-atherosclerotic actions of geniposide.However, we believe that several methodological aspects would benefit from greater clarification to enhance the mechanistic support for these various findings.After carefully reading the manuscript, we feel that the reasons for choosing particular dose and treatment duration of the PPAR antagonist GW9662 need further clarification.The in vitro studies were done using only one concentration (5 M) and one pretreatment period (1 h), without testing whether the treatment affects cell viability under these conditions.Earlier findings suggest that GW9662 can be cytotoxic or exhibit off-target effects that are PPAR noninhibitory. 2 The downregulation of M2 marker expression may not only be due to specific PPAR blockade, as it cannot be excluded that drug-induced effects on cellular state also caused this downregulation through nonspecific stress responses.In addition, GW9662 was given via intraperitoneal injection in the ApoE -/ -mouse model 1 mg/kg/day.Nevertheless, the regimen was not validated by any pharmacokinetic or pharmacodynamic data.Since GW9662 is known to have a poor in vivo bioavailability, 3 and there is no information regarding systemic exposure, tissue distribution (in particular the aorta) or inhibition of the target pathway, it remains unclear whether this dose achieved effective and selective PPAR blockade in vivo.Moreover, it would be beneficial to strengthen the evidence for the necessity of PPAR.Though GW9662 is commonly used as a selective PPAR antagonist, it is prone to off-target effects with high concentrations or under specific experimental conditions, possibly affecting other nuclear receptors such as PPAR or PPAR. 4,5Accordingly, reliance on pharmacological inhibition alone may not fully rule out PPAR-independent pathways.Using genetic methods like macrophage-specific PPAR knockdown or knockout would significantly strengthen the conclusion that Gen acts mainly through PPAR to promote M2 polarization.The evaluation of plaque stability seems somewhat limited, and we observed a slight methodological flaw in the study.The study appears to equate reduced plaque area with enhanced stability.While plaque area is clinically relevant, stability is more strongly determined by key histopathological features of vulnerability-namely, fibrous-cap thickness, collagen content, and necrotic core size.The conclusion regarding plaque stabilization is therefore constrained by the absence of these critical parameters.In addition, the restriction enzyme listed as "HandIII" in the Methods section is presumably a typo for "HindIII."