All endothelial cells are involved in the production of thrombomodulin EXCEPT those found in:
Hepatic circulation
Cutaneous circulation
Cerebral microcirculation
Renal circulation
Endothelium of the blood vessels plays an active role in preventing the extension of clots into blood vessels. All endothelial cells except those in the cerebral circulation produce thrombomodulin. Ref: Review of Medical Physiology By Ganong, 22nd Edition, Page 543; Robbins Pathologic Basis of Disease, 6th Edition, Page 120