Retention of haematoporphyrin in the aorta of hypertensive rats: in-vivo and in-vitro studies.

Abstract. Porphyrins are known to be accumulated and retained by tumours and atherosclerotic plaques. This property has been used for a new therapeutic approach called photodynamic therapy. In this study we assessed whether the presence of arterial hypertension could modify porphyrin turnover in the vascular wall. At various times after intravenous injection, haematoporphyrin concentration was assessed by a spectrophotofluorimetric method in the aortas of normotensive and hypertensive rats. Moreover, we studied the binding of haematoporphyrin to cultured smooth muscle cells obtained from normotensive and hypertensive rats. Larger amounts of haematoporphyrin were accumulated by the aorta of hypertensive rats and cleared at a slower rate, compared with normotensive rats. As for in‐vitro experiments, cultured smooth muscle cells from hypertensive rats bound larger amounts of haematoporphyrin than cells from normotensive rats. Copyright © 1988, Wiley Blackwell. All rights reserved