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New Directions

Hirudin
Hirudin is an anticoagulant peptide produced in trace amounts from the salivary glands of Hirudo medicinalis. It's the most potent thrombin inhibitor known, to date. Until recently, the use of hirudin was limited by the very small quantities available. Recombinant technologies are now making it possible to produce large quantities using yeast and bacteria cultures.

The United States Food and Drug Administration (FDA), approved a recombinant hirudin (lepirudin; rDNA) in 1998 to be used in patients with heparin-induced thrombocytopenia (HIT). HIT is a life threatening disease which typically occurs 4-14 days after exposure to heparin.

Hirudin is superior to heparin because:

It binds directly to thrombin
It does not effect endothelium
It can inhibit thrombin even in a clot
It promotes dissolution of mural thrombus and retards growth of thrombus even on deeply injured arteries.

Recombinant hirudin has allowed patients with HIT to undergo procedures requiring anticoagulation, including: cardiopulmonary bypass, endarterectomy, angioplasty, etc. It is also being used to treat deep venous thrombosis.

Instant feedback:

Hirudin is effective in treating DVT because it is able to inhibit the effects of thrombin even when it is bound in a clot.

Mechanical leech
While leeches have many positive factors, many people cringe at the thought of leech treatment. There are also problems that can arise, such as infections and the leeches migrating to parts of the body where they're not wanted. Doctors at the University of Wisconsin are developing a synthetic leech in the shape of a small glass and metal vial, with fluid running through it. The device mimics the leech's ability to relieve venous congestion and promote the growth of new vessels. The system provides a method for delivering and dispersing heparin to affected tissue. The device's porous tip, which is implanted just beneath the skin, rotates to further inhibit coagulation. While a real leech sucks up only a limited amount of blood, the mechanical leech is essentially insatiable. The goal of the study was to develop and test a working prototype of a mechanical device designed to remove blood from congested tissues after medicinal leech detachment. The hypothesis was that the device could augment blood retrieval during the passive blood loss after the leech detaches. It is hoped that the mechanical leech will eventually be able to augment or replace the natural leech. It is currently undergoing animal trials.