Delayed prolonged leakage following tissue injury is due to:

Delayed prolonged leakage is believed to be caused either by the direct effect of injurious agent or by cytokine mediated endothelial retraction. It is not caused by cytokine mediated vasodilatation and cytokine mediated endothelial retraction is not provided in the options. Direct effect of injuring agent is therefore the single best answer of choice. Ref: Robbin's Illustrated Pathology, 7th Edition, Pages 51, 52 ; Pathology By Holliman, 4th Edition, Page 22