Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Heart Disease Linked to Evolutionary Changes That May Have Protected Early Mammals from Trauma

19.10.2011
Can a bird have a heart attack?

A new study by researchers at the Perelman School of Medicine at the University of Pennsylvania suggests that cardiovascular disease may be an unfortunate consequence of mammalian evolution. The study, published in a recent issue of the journal Blood, demonstrates that the same features of blood platelets that may have provided an evolutionary advantage to early mammals now predispose humans to cardiovascular disease.

“The biology of platelets has been studied in great detail in the context of human disease, but almost nothing is known about why mammals have platelets, whereas no other species do,” said lead study author Alec A. Schmaier, PhD, an MD/PhD student in the lab of Mark Kahn, MD, professor of Medicine at Penn. “This new line of research suggests that platelets could have allowed mammals to better survive traumatic injury by being able to form cellular clots in arterial blood vessels. The price for this evolutionary change may be modern cardiovascular diseases.”

Platelets are small circulating cells that have no nucleus and form clots at sites of vessel injury. Platelets are required to prevent excessive bleeding following traumatic injury, but they also form clots at sites of atherosclerotic plaques in the blood vessels that lead to stroke and heart attack. Drugs that inhibit the function of platelets, including aspirin and clopidogrel, are the main weapons for treating heart attack and stroke.

Despite being a vital element of the blood clotting system, platelets are only found in mammals, whereas all non-mammalian vertebrates, including birds, have thrombocytes. About twice the diameter of platelets, thrombocytes contain a nucleus. Studies performed in the 1970s suggested they have a clotting function similar to platelets, but extensive studies of thrombocytes using modern experimental techniques have not been performed.

The research team focused their study on birds (compared to fish or reptiles for example) because birds and mammals both have a high pressure arterial system. Birds in fact have higher cardiac output and blood pressures than mammals do. Therefore, the challenge for hemostasis, i.e. blood clotting after vessel injury or trauma, should be similar between a mammal and a bird. However, in the present study, using molecular and physiologic techniques, the Penn researchers discovered that avian thrombocytes express most of the same proteins as platelets, with two key exceptions: thrombocytes express a significantly lower level of one essential platelet protein (the fibrinogen receptor) and are completely deficient in another (the adenosine diphosphate receptor) that function in a pathway required to form occlusive clots in the arterial system and are the primary targets of anti-platelet medications. In collagen flow-chamber experiments, the research team found that thrombocytes could not form 3-dimensional aggregates under high-flow conditions, a key step in the pathogenesis of stroke and heart attack.

Collaborative studies with colleagues at Penn's School of Veterinary Medicine, Karen Rosenthal, DVM, MS, and Jeff Runge, DVM, and Tim Stalker, in Department of Medicine –Hematology/Oncology, at the Perelman School of Medicine, next compared the ability of platelets and thrombocytes to form intra-vascular clots in mice and similarly sized parakeets. The mice, but not the birds, developed clots that prevented blood flow after arterial injury due to the ability of platelets, but not thrombocytes, to stick to each other under high flow conditions.

Although the researchers caution that this prediction cannot be tested in all contexts, the finding that equivalent degrees of arterial vessel wall injury in vessels of similar size and equal hemodynamic forces result in the occlusion in mammals but not in birds is consistent with the hypothesis that platelets mediate a more efficient clotting response than thrombocytes.

Dr. Kahn, the study’s senior author, concluded, “Although the reason for platelet evolution in mammals can never be known with certainty, it is tempting to speculate that platelets may have allowed early mammals to better survive trauma and thereby provided a survival advantage.”

The research was supported by National Institute of Health and by an American Heart Association (AHA) postdoctoral fellowship.

Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4 billion enterprise.

Penn's Perelman School of Medicine is currently ranked #2 in U.S. News & World Report's survey of research-oriented medical schools and among the top 10 schools for primary care. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $507.6 million awarded in the 2010 fiscal year.

The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top 10 hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital – the nation's first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2010, Penn Medicine provided $788 million to benefit our community.

Jessica Mikulski | Newswise Science News
Further information:
http://www.uphs.upenn.edu

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>