Danish Cardiovascular Giraffe Research Project (DaGiR)

DaGiR is an interdisciplinary project, started by Prof. Christian Aalkjaer in 2005, investigating the giraffes amazing physiology.
The study is based on ”The August Krogh principle”, named after the Danish physiologist and nobel laureate August Krogh, who in 1929 formulated this principle;

"For a large number of problems there will be some animal of choice or a few such animals on which it can be most conveniently studied"
(A. Krogh; Am J.Physiol. 90:243,1929)

The aim of the project is to elucidate the mechanisms that enables the giraffe to have a blood pressure twice the human blood pressure^1-3 without developing the pathological lesions in the cardiovascular system that are commonly observed in hypertensive humans.
Furthermore, the project investigate the adaptations of the giraffe’s cardiovascular system that enables it to endure dramatic changes in blood pressure, as when the head is lower the head to drink. A motion that theoretically would lead to an increase in cerebral perfusion pressure from ~100mmHg to ~400 mmHg, and which is reversed in less than a second when the head is raised again, without the giraffe showing any signs of orthostatic hypotension.The giraffe’s high blood pressure and tall stature also entails a very high pressure perfusion pressure of the organs and a high pressure in the resistance arteries of the legs. Despite these high pressures, the giraffes show no signs of organ damage or lower leg edema.
By investigating the adaptations of the giraffe’s cardiovascular system we intent to contribute with new and exiting insight on the mammalian cardiovascular system.

About the project
The project is headed by Prof. Aalkjaer in collaboration with prof. J. Michael Hasenkam (Clinical Insitute, Aarhus University Hospital, Skejby) and prof. Tobias Wang (Institute of Biology, Aarhus University). Cand. scient. PhD. Student Emil T. Brøndum is part time employed as daily administrator.  The project group includes more than 30 scientist representing 8 universities in 4 countries. The team members includes cardiac surgeons, anaesthesiologists, radiologists, pathologists, anatomists, biologists, wild-life experts, veterinarians, linguistics, nurses, technicians and students.In 2006 the DaGiR project arranged a 16 day expedition to South Africa where 6 giraffes was investigated in a setup that enabled us to keep an anesthetized giraffe in upright position. The study resulted in a number of publications^3-5 numerous international scientific presentations and data from the experiments have been extensively used in pre-graduate education.
In autum 2010 the DaGiR group made a second expedition with more than 35 researchers in Africa for more than 25 days doing research on giraffes, including extensive myograph experiments in a portable laboratory.

For more information on the study, please contact project coordinator
Emil Brøndum, etb@fi.au.dk

Reference List

(1)   Hargens AR, Millard RW, Pettersson K, Johansen K. Gravitational Hemodynamics and Edema Prevention in the Giraffe. Nature 1987; 329(6134):59-60.
(2)   Goetz RH, Keen EN. Some aspects of the cardiovascular system in the giraffe. Angiology 1957; 8:542-564.
(3)   Brondum E, Hasenkam JM, Secher NH, Bertelsen MF, Grondahl C, Petersen KK et al. Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe. Am J Physiol Regul Integr Comp Physiol 2009; 297(4):R1058-R1065.
(4)   Bertelsen MF, Østergaard KH, Brondum ET, Monrad J, Baandrup U. Monodontella giraffae infection in wild caught southern giraffes, Giraffa camelopardalis giraffa. Journal of Wildlife Diseases 2009; 45(10).
(5)   Østergaard KH, Bertelsen MF, Brondum ET, Aalkjaer C, Hasenkam JM, Smerup M et al. Pressure profile and structural changes of the arteries along the giraffe hindlimb. Hypertension 2009; Submitted.