Featured Research

from universities, journals, and other organizations

Blood Vessels Grown In Live Animals

Date:
November 20, 2001
Source:
Whitaker Foundation
Summary:
Biomedical engineers at the University of Michigan have grown a healthy network of blood vessels in live animals using implants that deliver critical growth enzymes sequentially as in nature.

ARLINGTON, Va., -- Biomedical engineers at the University of Michigan have grown a healthy network of blood vessels in live animals using implants that deliver critical growth enzymes sequentially as in nature.

Related Articles


"To grow a replacement tissue cell by cell, you need a combination of growth factors delivered in the right sequence at the proper time and in the right place," said David Mooney, Ph.D., professor of biologic and materials science at Michigan and a Whitaker Investigator. "Just injecting a large amount of it with a needle doesn't work."

The experiments, reported in the current issue of the journal Nature Biotechnology, represent an early step toward growing new tissues in the human body, since all living tissues require blood circulation.

Possible medical applications include alternatives to heart bypass surgery, faster wound healing, and treatments for vascular disease in diabetics. The implants might also be used to deliver other drugs or therapeutic agents.

At least two enzymes or growth factors are needed for new blood vessels: vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). VEGF initiates vessel growth, while PDGF promotes maturation by giving the vessels a strong interior lining. The continued presence of VEGF also prevents vessels from regressing as they mature.

The research group attempted to duplicate the sequential release of the growth factors by mixing them with a polymer in different ways and then melding everything into a porus scaffold to be implanted. As the scaffold dissolved, it released the growth factors one before the other with some overlap. The scaffold is designed to disappear altogether over time.

The Michigan group mixed VEGF with particles of the polymer for immediate and sustained release and encapsulated PDGF in polymer microspheres for slow release. The release rate and amount were controlled by the thickness and number of microspheres. Both the polymer-particle mixture and the microspheres were combined to make the scaffold.

The researchers conducted three experiments. First they confirmed the release rates of both growth factors in laboratory dishes, then implanted four types of scaffolds in healthy rats. One type contained VEGF alone, another PDGF, the third had both, the fourth neither. The rats were examined after two weeks and again in a month. Only rats that received both growth factors had grown new, mature blood vessels after four weeks.

In the third study, the researchers attempted to treat vascular disease in 16 diabetic mice using the same combination of four scaffold types. Again, only the dual-release scaffolds stimulated a mature vascular network.

Peter Carmeliet and Edward M. Conway of the University of Leuven in Belgium commented on the research in the same issue of Nature Biotechnology. They compared the Michigan approach to contemporary efforts to stimulate blood vessel formation using other methods, such as gene transfer, noting that none of the othermethods mimicked nature's timed-release delivery of multiple growth factors.

"Obviously, future work is needed to demonstrate the value of this system for [therapy]," they wrote. "Nonetheless, the exciting findings ... underscore the importance of paying attention to not only the type of angiogenic growth factor employed for therapeutic angiogenesis, but also how and when they should be delivered."

Mooney's group included postdoctoral student Thomas P. Richardson and graduate students Martin C. Peters, a Whitaker Fellow, and Alessandra B. Emmett. Mooney received a Biomedical Engineering Research Grant from the foundation in 1995 for tissue engineering research. Peters received a Whitaker Foundation Graduate Fellowship in 1996.


Story Source:

The above story is based on materials provided by Whitaker Foundation. Note: Materials may be edited for content and length.


Cite This Page:

Whitaker Foundation. "Blood Vessels Grown In Live Animals." ScienceDaily. ScienceDaily, 20 November 2001. <www.sciencedaily.com/releases/2001/11/011120044601.htm>.
Whitaker Foundation. (2001, November 20). Blood Vessels Grown In Live Animals. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2001/11/011120044601.htm
Whitaker Foundation. "Blood Vessels Grown In Live Animals." ScienceDaily. www.sciencedaily.com/releases/2001/11/011120044601.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins