Bradykinin

Immunology

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Description

Bradykinin is a potent vasodilating peptide which exerts its action through the stimulation of specific endothelial B2 receptors, leading to the release of smooth muscle relaxants such as prostacyclin and endothelium-derived hyperpolarising factor. This binding of Bradykinin to the B2 receptors also increases vascular permeability [1]. Bradykinin is a product of the kallikrein-kinin system, production of which is controlled by C1 esterase inhibitor (C1inh). The reduction /absence of C1inh in HAE type 1, or non-functioning C1inh in HAE type 2 leads to a loss of inhibition of Bradykinin production, therefore circulating levels increase [2]. High levels of Bradykinin results in over activation of beta 2-Bradykinin receptors and subsequently increased tissue permeability, vasodilation and oedema, the causative factors behind the characteristic symptoms of localised swelling, inflammation and pain which are associated with active HAE attack [2,3]. Raised Bradykinin may also be seen in acquired angioedema (AAE) and Renin-angiotensin-aldosterone system (RAAS)-blocker induced angioedema (including ACE-induced angioedema) [4].

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Indications

Active Bradykinin-mediated attack associated with Hereditary angioedema (HAE).

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Sample Type

2mL EDTA whole blood. The sample should be sent to the laboratory within 2 hours of venesection. Alternatively ethanol extraction and evaporation of the sample may be performed in referring laboratories. Send extract frozen to the Immunology department. The approved extraction protocol can be distributed on request.

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Reference Range

Normal range <1ng/mL.Reference range verified in-house.

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Turnaround Time

Within 4 weeks

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Testing Frequency

3 weeks

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External Notes

Contact the Sheffield PRU for the sample extraction protocol.

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See Also

C3, C4, C1 Inhibitor

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