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 Self-organising system enables motile cells to form complex search pattern
07.05.2019 | Westfälische Wilhelms-Universität Münster

nachricht Mouse studies show minimally invasive route can accurately administer drugs to brain
02.05.2019 | Johns Hopkins Medicine

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: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Uncovering hidden protein structures

18.06.2019 | Life Sciences

Monitoring biodiversity with sound: how machines can enrich our knowledge

18.06.2019 | Life Sciences

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>