THE MEDICAL INSPIRATION OF THE HUMBLE LEECH

BY: DEEPAK PATEL

OUTLINE WHAT IS A LEECH

TYPES OF LEECHES BIOLOGICAL SPECIES USED – MEDICINAL LEECH HABITAT ANATOMY OF THE LEECH

ADMINISTRATION OF LEECH THERAPY Pre Procedure Procedure Post Procedure

APPLICATIONS Historical applications Modern uses of leech therapy

COMPLICATIONS ADVANCEMENTS

MECHANICAL LEECH CHEMICAL ADVANCEMENTS (BIVALIRUDIN)

WHAT IS A LEECH

Leeches are annelids or segmented worms, closely related to the earthworms, are

anatomically and behaviourally more specialized.

CLASSIFICATION OF LEECHES EUHIRUDINE

-with both anterior and posterior suckers

Rhynchobdellae-these are jawless armed with muscular

straw like probiscus and a retractable sheath

Glossiphoniidae

Piscicolidae

Arhynchobdellae- These lack a probiscus and which may or

may not have jaws armed with teeth

Gnathobdelae-European Medicinal Leech

( Hirudo Medicinalis)

Pharyngobdellae

BIOLOGICAL SPECIES USED The medicinal leech or

Hirudo medicinalis is used therapeutically.

DESCRIPTION – Fully mature adults can be

up to 20cm in length are green, brown or

greenish brown darker tone on the dorsal

side and a lighter ventral side

the dorsal side also has a thin red stripe.

Natural Habitat of the LeechThe preferred habitat for this species

is muddy freshwater pools and ditches with plentiful weed growth.

Most leeches are freshwater animals, but many terrestrial and marine species occur.

ANATOMY OF THE LEECH

ADMINISTRATION OF LEECH THERAPY

PRE PROCEDUREPROCEDUREPOST PROCEDURE

PRE PROCEDURE

PROCEDURE

POST PROCEDURE

APPLICATIONS OF LEECH THERAPY

Historical applicationsModern uses of leech therapy

Plastic / Reconstructive Surgery Meningococcal purpura fulminans Osteoarthiritis

HISTORICAL APPLICATIONS

200 BC – Nicader of Colophain

129-199 AD - Galen

1800’s – High Demand

End of 19th Century – Use began declining, However, in 1884 Haycraft isolated Hirudin

1955 – Hirudin was finally isolated and characterised.

USE IN PLASTIC AND RECONSTRUCTIVE SURGERY

Used to relieve venous congestionThus leeches are used to prevent

pooling of blood.The leech sucks the blood thereby

increasing perfusion of the tissue and maintains tissue viability until neovascularization occurs.

HOW THE LEECH HELPS?Application of medical leech

reportedly increases blood flow within congested tissue via active feeding and indirectly by passive bleeding from the leech bite after detachment.

Active & Passive bleeding are both facilitated by the actions of different salivary secretions of the leech such as hirudin – an anticoagulant.

Example of leech being used in reconstructive surgery of the ear

24 hourspostoperative

48 hours postoperative

72 hourspostoperative

6 dayspostoperative

2 monthspostoperative

CONTENTS OF LEECH SALIVA

The most important constituent – hirudin

Other substances which have anaesthetic action, vasodilator, anti-inflammatory and analgesic action

TREATMENT OF MENINGOCOCCAL PURPURA FULMINANS

What is Meningococcal purpura fulminans?

What happens in Meningococcal purpura fulminans?

How do leeches help in treatment of this condition?

USE OF LEECHES TO TREAT OSTEOARTHRITIS

The saliva of the leeches contain a large number of substances which are found to have anti-inflammatory and analgesic properties which have still not been properly characterized.

It was suspected that the anti-inflammatory and analgesic agents in leech saliva could be used for the symptomatic treatment of osteoarthritis.

Currently this hypothesis is being tested. They have found that there was a rapid pain

relieving effect from the leeches, without any complications.

However, since the treatment is unusual, they could not compare with any placebo.

COMPLICATIONS

Aeromonas veronii and other species of Aeromonas.Transfusion of blood may be required.

INSPIRATION - ADVANCEMENTS

Mechanical LeechChemical Advancements

(Bivalirudin)

MECHANICAL LEECH?

A DEVICE TO AUGMENT BLOOD REMOVAL AFTER PASSIVE BLEEDING

WORKING OF THE MECHANICAL LEECH

CHEMICAL ADVANCEMENTS –BIVALIRUDIN

Semisynthetic derivative of Hirudin. It consists of 20 amino acids formed

from residues 53 to 64 of hirudin with addition of a sulphated tyrosine at position 63.

Peptide Sequence of Bivalirudin

PEPTIDE SEQUENCE OF BIVALIRUDIN

Peptide Sequence of Bivalirudin

Bivalirudin consists of 3 domains1) The –COOH terminal domain2) The –NH2 terminal domain3) The linker tetraglycine chain

MECHANISM OF ACTION OF HIRUDIN AND BIVALIRUDIN

EXOSITE 1

EXOSITE 2ACTIVE SITE

ADVANTAGES OVER HEPARIN

Bivalirudin inhibits clot bound thrombin as well as circulating thrombin.

Unfractionated Heparin binds to plasma protein and therefore is unpredictable.

Low Molecular Weight Heparin binds comparatively lesser to plasma proteins but many other disadvantages compared to Bivalirudin.

ADVANTAGES OF BIVALIRUDIN OVER HIRUDIN

Hirudin is a 65 amino acid peptide and due to its larger size may induce immunogenic reactions (However none are reported as yet)

Plasma half life of Hirudin is 2- 3 hours as compared to Bivalirudin (30 minutes).

Bivalirudin has 1000 times lower affinity for thrombin as compared to Hirudin and therefore is a reversible inhibitor of thrombin.

USES OF BIVALIRUDIN

Percutaneous Coronary Intervention (Angioplasty)

Acute Coronary Syndromes

Heparin Induced Thrombocytopenia

Vascular Brachytherapy

Percutaneous Peripheral Intervention.

Conclusion

THANK YOU

REFERENCES Trease & Evans ( Ed.) Pg. 443 Wikipedia –http://en.wikipedia.org/wiki/Leech

MARK D. WELLS, ET. AL. THE MEDICAL LEECH: AN OLD TREATMENT REVISITED, MICROSURGERY 14:183-186 1993.

A. Eldor, M. Orevi, M. Rigbi The role of the leech in medical therapeutics, Blood Reviews (1996) 10,201-209.

James J. Nawarskas et. al. Bivalirudin A New Approach to Anticoagulation, Heart Disease 2001;3:131–137

Nicolas W. Shammas, Bivalirudin: Pharmacology and Clinical Applications, Cardiovascular Drug Reviews Vol. 23, No. 4, pp. 345–360.

Ricky Dippenaar et. al. Meningococcal purpura fulminans treated with medicinal leeches. Pediatric Care Med 2006 Vol. 7, No. 5 Pg- 476-478.

Claire L. Haycox, MD, PhD. et al. Indications and complications of medicinal leech therapy, Journal of the American Academy of Dermatology Volume 33. Number 6, Pg. 1053-1055.

Andreas Michalsen et. al. Leech therapy for symptomatic treatment of knee osteoarthritis: Results and implications of a pilot study Alternative Therapies in Health and Medicine. Aliso Viejo: Sep/Oct 2002. Vol. 8, Iss. 5; pg. 84, 5 pgs.

Nadine P. Connor, et. al. Augmented blood removal after medicinal leech feeding in congested tissue flaps. Journal of Rehabilitation Research and Development. Vol. 39 No. 4, July/August 2002 Pages 505-512

Australian Museum Online – http://www.amonline.net.au/factsheets/leeches.html