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The cover shows efflux of 0.45-μm red microspheres from the vascular circulation (labeled in green) toward collagen matrix (in blue) within an inflamed joint of a mouse. These observations document the presence of gaps between endothelial cells in the vasculature during inflammation, consistent with increased tissue edema and likely similar to human inflammatory conditions such as arthritis. Although platelets are conventionally assigned the role of preserving vascular integrity, they are capable of triggering the formation of gaps during inflammation via serotonin release, a process inhibited by serotonin-specific reuptake inhibitor antidepressant drugs. This demonstration that platelets are capable of amplifying and maintaining vascular permeability adds to the rapidly growing list of unexpected functions for platelets. See the article by Cloutier et al on page 1334.