Heparin a key role player in allergy and inflammatory reactions

Heparin has a long history at Karolinska Institutet, since here the substance was originally purified and its chemical structure was characterized back in 1935 by Professor Erik Jorpes. Knowing about the therapeutic implications Jorpes was one of the pioneers treating patients that suffered from thrombosis with heparin infusions. Today, heparin is still one of the most commonly used anticoagulant drugs.

Professor Jorpes showed that heparin is produced in a specific blood-born cell population, called mast cells. Mast cells have a central function in allergic and inflammatory diseases and contribute to increased vascular permeability, allergic and anaphylactic reactions. The current study identifies the underlying mechanism and its therapeutical implications. The authors show that heparin initiates the production of a hormone – bradykinin – that contributes to swelling, anaphylactic and inflammatory symptoms, which are commonly known to be associated with aberrant mast cell activity.

Notably, mast cell-released heparin generates the inflammatory mediator bradykinin via activation of factor XII (the so-called Hageman Factor) that belongs to the blood coagulation system. The study thus provides an unexpected link between the clotting cascade and mast cell-driven pro-inflammatory reactions. Drugs that block bradykinin or factor XII activity protect from adverse mast cell-driven effects in patients and genetically engineered mouse models and could be a new strategy to treat allergic diseases.

Karolinska Institutet is one of the world’s leading medical universities. It accounts for over 40 per cent of the medical academic research conducted in Sweden and offers the country’s broadest range of education in medicine and health sciences. Since 1901 the Nobel Assembly at Karolinska Institutet has selected the Nobel laureates in Physiology or Medicine. More information on ki.se

Publication: ‘Mast cells increase vascular permeability by heparin-initiated bradykinin formation in vivo’, Chris Oschatz, Coen Maas, Bernd Lecher, Thomas Jansen, Jenny Björkqvist, Thomas Tradler, Reinhard Sedlmeier, Peter Burfeind, Sven Cichon, Sven Hammerschmidt, Werner Müller-Esterl, Walter A. Wuillemin, Gunnar Nilsson & Thomas Renné, Immunity, February 25, 2011, Volume 34, Issue 2.