Featured Research

from universities, journals, and other organizations

Insulin-producing Pancreatic Cells Are Replenished By Duplication

Date:
May 6, 2004
Source:
Harvard University
Summary:
Researchers at Harvard University and the Howard Hughes Medical Institute (HHMI) have discovered that insulin-producing beta cells in the pancreas that are attacked in type 1 diabetes are replenished through duplication of existing cells rather than through differentiation of adult stem cells.

The experiments do not rule out the possibility that there are adult stem cells in the pancreas, but do suggest strongly that embryonic stem cells or mature beta cells may be the only way to generate beta cells for use in cell replacement therapies. (Staff photo Justin Ide/Harvard News Office)

Researchers at Harvard University and the Howard Hughes Medical Institute (HHMI) have discovered that insulin-producing beta cells in the pancreas that are attacked in type 1 diabetes are replenished through duplication of existing cells rather than through differentiation of adult stem cells.

Related Articles


Although the experiments, which were done using mice, do not rule out the possibility that there are adult stem cells in the pancreas, the researchers say that they do suggest strongly that embryonic stem cells or mature beta cells may be the only way to generate beta cells for use in cell replacement therapies to treat diabetes.

The research team, which was led by Douglas A. Melton, Thomas Dudley Cabot Professor of the Natural Sciences in the Faculty of Arts and Sciences (FAS) and an HHMI investigator, reports its findings in a research article published in the May 6 issue of the journal Nature. Melton's co-authors include Yuval Dor, Juliana Brown, and Olga I. Martinez, all of Harvard's Department of Molecular and Cellular Biology.

In cell culture, embryonic stem (ES) cells retain the properties of undifferentiated embryonic cells. ES cells have the capacity to make all cell types found in an adult organism. One of the most hotly debated questions in biology is whether adult stem cells, which have been isolated from blood, skin, brain, and other organs, have the same developmental capacity as ES cells.

Researchers have known for some time that ES cells can give rise to pancreatic beta cells during development. "But the more interesting question for us has been what happens in mature pancreatic tissue to both maintain the pancreas and to regenerate it," said Melton. "Previous studies have suggested that there are sources of adult stem cells that might give rise to beta cells. However, those studies had largely depended on histological 'snapshots' of tissues." Those snapshots can only suggest the "geographic" origin of new beta cells and not the identity of the cells from which they arise, Melton noted.

Melton and his colleagues knew that they could finally put such questions to rest if they could tag beta cells in such a way that they could determine unequivocally whether the new cells were made from existing beta cells or from a different reservoir of stem cells. For these studies, they devised a "genetic lineage tracing" technique that involved engineering a mouse whose beta cells contained a telltale genetic marker that could be switched on by administering the drug tamoxifen.

The logic behind the technique is relatively straightforward: When the researchers administer tamoxifen to the adult mice, they can easily follow the marker to determine whether it is inherited by subsequent generations of beta cells. If it is inherited, then the cells expressing the marker are the offspring of pre-existing beta cells.

When the researchers applied their technique to the mice, they discovered that all the new beta cells they examined - whether arising in the usual process of renewal or during regeneration following partial removal of the pancreas - were generated from pre-existing beta cells. According to Melton, the finding highlights a largely unappreciated capability of beta cells.

"No one has really paid much attention to the replicative capacity of the beta cell," he said. "And this work shows the cells to have a significant proliferative capacity that could be clinically useful."

According to Melton, the findings might have implications for developing treatments for type 1 diabetes, a disease that destroys beta cells. "If such people have residual beta cells, these findings suggest that a useful clinical direction would be to find a way to boost the proliferative capacity of those beta cells, to restore insulin production in such patients.

"On the other hand, if type 1 diabetics don't have any beta cells left, then these findings suggest that the only source of new beta cells is probably going to be embryonic stem cells, because there don't appear to be adult stem cells involved in regeneration."

Melton emphasized that although the results by his group cannot rule out the existence of beta-cell-producing adult stem cells, "they raise the bar on trying to demonstrate their existence. In these experiments, we find no evidence for the existence of adult pancreatic stem cells," he said.

The genetic lineage tracing technique devised by Melton's group is a tool that can now be used to trace the origin of cells involved in the maintenance and repair of other types of tissue. Melton and his colleagues are already using the technique to determine the origin of new cells in lung tissue. And it should be possible to apply the technique to understand the origin of cancer cells in tumors or to understand the role of stem cells in such malignancies, Melton said.

This research was supported by the European Molecular Biology Organization and the Juvenile Diabetes Research Foundation.


Story Source:

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


Cite This Page:

Harvard University. "Insulin-producing Pancreatic Cells Are Replenished By Duplication." ScienceDaily. ScienceDaily, 6 May 2004. <www.sciencedaily.com/releases/2004/05/040506074327.htm>.
Harvard University. (2004, May 6). Insulin-producing Pancreatic Cells Are Replenished By Duplication. ScienceDaily. Retrieved January 27, 2015 from www.sciencedaily.com/releases/2004/05/040506074327.htm
Harvard University. "Insulin-producing Pancreatic Cells Are Replenished By Duplication." ScienceDaily. www.sciencedaily.com/releases/2004/05/040506074327.htm (accessed January 27, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, January 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Mistakes Should Serve a Lesson Says WHO

Ebola Mistakes Should Serve a Lesson Says WHO

AFP (Jan. 25, 2015) The World Health Organization&apos;s chief on Sunday admitted the UN agency had been caught napping on Ebola, saying it should serve a lesson to avoid similar mistakes in future. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Disneyland Measles Outbreak Spreads To 5 States

Disneyland Measles Outbreak Spreads To 5 States

Newsy (Jan. 24, 2015) Much of the Disneyland measles outbreak is being blamed on the anti-vaccination movement. The CDC encourages just about everyone get immunized. Video provided by Newsy
Powered by NewsLook.com
Growing Measles Outbreak Worries Calif. Parents

Growing Measles Outbreak Worries Calif. Parents

AP (Jan. 23, 2015) Public health officials are rushing to contain a measles outbreak that has sickened 70 people across 6 states and Mexico. The AP&apos;s Raquel Maria Dillon has more. (Jan. 23) Video provided by AP
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
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