Oxidative degradation of bilirubin produces vasoactive compounds

Kranc, K.R., Pyne, G.J., Tao, L., Claridge, T.D.W., Harris, D.A., Cadoux-Hudson, T.A.D., Turnbull, J.J., Schofield, C.J. and Clark, J.F. (2001) Oxidative degradation of bilirubin produces vasoactive compounds. European Journal of Biochemistry, 267(24), pp. 7094-7101. (doi: 10.1046/j.1432-1327.2000.01812.x)

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Publisher's URL: http://dx.doi.org/10.1046/j.1432-1327.2000.01812.x

Abstract

Subarachnoid haemorrhage is often followed by haemolysis and concomitant oxidative stress, and is frequently complicated by pathological vasoconstriction or cerebral vasospasm. It is known that upregulation of haem oxygenase (HO-1) is induced by oxidative stress and results in release of biliverdin and bilirubin (BR), which are scavengers of reactive oxygen species (ROS). Here we report biomimetic studies aimed at modelling pathological conditions leading to oxidative degradation of BR. Oxidative degradation products of BR, formed by reaction with hydrogen peroxide (an ROS model system), demonstrated biological activity by stimulating oxygen consumption and force development in vascular smooth muscle from porcine carotid artery. Analogous biological activity was observed with vasoactive cerebrospinal fluid from subarachnoid haemorrhage patients. Three degradation products of BR were isolated: two were assigned as isomeric monopyrrole (C<sub>9</sub>H<sub>11</sub>N<sub>2</sub>O<sub>2</sub>) derivatives, 4-methyl-5-oxo-3-vinyl-(1,5-dihydropyrrol-2-ylidene)acetamide and 3-methyl-5-oxo-4-vinyl-(1,5-dihydropyrrol-2-ylidene)acetamide and the third was 4-methyl-3-vinylmaleimide (MVM), a previously isolated photodegradation product of biliverdin. Possible mechanisms of oxidative degradation of BR are discussed. Tentative assignment of these structures in the cerebrospinal fluid (CSF) of cerebral vasospasm patients has been made. It is proposed that one or more of the degradation products of biliverdin or bilirubin are involved in complications such as vasospasm and or pathological vasoconstriction associated with haemorrhage.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kranc, Professor Kamil
Authors: Kranc, K.R., Pyne, G.J., Tao, L., Claridge, T.D.W., Harris, D.A., Cadoux-Hudson, T.A.D., Turnbull, J.J., Schofield, C.J., and Clark, J.F.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:European Journal of Biochemistry
ISSN:0014-2956
ISSN (Online):1432-1033
Published Online:25 December 2001

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