(Press-News.org) Tampa, Fla. (June 4, 2012) – After carrying out a study comparing the repopulation efficiency of immature hepatic stem/progenitor cells and mature hepatocytes transplanted into liver-injured rats, a research team from Sapporo, Japan concluded that mature hepatocytes offered better repopulation efficiency than stem/progenitor cells.
Until day 14 post-transplantation, the growth of the stem/progenitor cells was faster than the mature hepatocytes, but after two weeks most of the stem/progenitor cells had died. However, the mature hepatocytes continued to survive and proliferate one year after their implantation.
The study is published in Cell Transplantation (21:1), now freely available on-line at http://www.ingentaconnect.com/content/cog/ct/.
"Cell-based therapies as an alternative to liver transplantation to treat liver disease have shown promise," said study corresponding author Dr. Toshihiro Mitaka of the Cancer Research Institute of the Sapporo Medical University School of Medicine, Sapporo, Japan. "However, the repopulation efficiency of two candidate cell sources - hepatic progenitor/stem cells and mature hepatocytes - had not been comprehensively assessed and questions concerning the efficiency of each needed to be resolved."
The researchers noted that the shortage of cell sources and the difficulties of cryopreservation have limited the clinical application of cell based therapies. Stem or progenitor cells have been considered candidate cells because they can expand in vitro and can be cryopreserved for a long time.
However, after transplantation into liver injured rats, the researchers found that stem/progenitor cells did not survive well and most of the transplanted cells had disappeared within two months. In contrast, the mature hepatocytes gradually repopulated the rat livers and continued doing so past one year.
The researchers noted that the sizes of the hepatocytes were not uniform.
"Unexpectedly, the small hepatocytes repopulated significantly less well than the larger ones," explained Dr. Mitaka. "We also found that serial transplantation did not enhance nor diminish the repopulation capacity of the cells to any significant degree."
The researchers concluded that because the stem/progenitor cells had died much earlier than the mature hepatocytes, most were immediately excluded from the host livers, reducing their potential impact on liver generation.
"Further experiments are required to clarify the mechanism by which this might occur," concluded the authors.
"This study suggests that mature hepatocytes may be a better treatment option than stem cells" said Dr. Stephen Strom of the Karolinska Institute, Sweden and section editor for Cell Transplantation. "However, determining the factors that allow for the survival and continued growth of the stem/progenitor and mature hepatocytes could be relevant for future improvements of hepatocyte transplantation in the clinic".
###
Contact: Toshihiro Mitaka, MD, PhD, Department of Pathophysiology, Cancer Research Institute, Sapporo medical University School of medicine, South-1, West-17, Chou-ku, Sapporo 060-8556, Japan
Tel. +81-11-611-2111 ext. 2390
Fax. +81-11-615-3099
Email tmitaka@sapmed.ac.jp
Citation: Ichinohe, N.; Kon, J.; Sasaki, K.; Nakamura, Y.; Ooe H.; Tanimizu, N.; Mitaka, T. Growth ability and repopulation efficiency of transplanted hepatic stem cells, progenitor cells, and mature hepatocytes in retrorsine-treated rat livers. Cell Transplant. 21(1):11-22; 2012.
The Coeditor-in-chief's for Cell Transplantation are at the Diabetes Research Institute, University of Miami Miller School of Medicine and Center for Neuropsychiatry, China Medical University Hospital, TaiChung, Taiwan. Contact, Camillo Ricordi, MD at ricordi@miami.edu or Shinn-Zong Lin, MD, PhD at shinnzong@yahoo.com.tw or David Eve, PhD at celltransplantation@gmail.com
News release by Florida Science Communications
END
Tampa, Fla. (June 4, 2012) – When autologous (self-donated) lung-derived mensenchymal stem cells (LMSCs) were transplanted endoscopically into 13 adult female sheep modeled with emphysema, post-transplant evaluation showed evidence of tissue regeneration with increased blood perfusion and extra cellular matrix content. Researchers concluded that their approach could represent a practical alternative to conventional stem cell-based therapy for treating emphysema.
The study is published in Cell Transplantation (21:1), now freely available on-line at http://www.ingentaconnect.com/content/cog/ct/.
...
The mosquito is possibly summer's biggest nuisance. Sprays, pesticides, citronella candles, bug zappers — nothing seems to totally deter the blood-sucking insect. And neither can rain apparently.
Even though a single raindrop can weigh 50 times more than a mosquito, the insect is still able to fly through a downpour.
Georgia Tech researchers used high-speed videography to determine how this is possible. They found the mosquito's strong exoskeleton and low mass render it impervious to falling raindrops.
The research team, led by Assistant Professor of Mechanical Engineering ...
WEST LAFAYETTE, Ind. - A new Purdue University-developed process for creating biofuels has shown potential to be cost-effective for production scale, opening the door for moving beyond the laboratory setting.
A Purdue economic analysis shows that the cost of the thermo-chemical H2Bioil method is competitive when crude oil is about $100 per barrel when using certain energy methods to create hydrogen needed for the process. If a federal carbon tax were implemented, the biofuel would become even more economical.
H2Bioil is created when biomass, such as switchgrass or corn ...
As voters increasingly rely on websites of presidential primary candidates for news, they run a risk because candidates' online attacks are not vetted through traditional "watchdog journalists" and other gatekeepers to determine accuracy or fairness, according to a study by Baylor University researchers.
"The primary danger is that constituents often use this one-sided information to decide how to vote," said Mia Moody, Ph.D., study co-author and an assistant professor of journalism, public relations and new media in Baylor's College of Arts & Sciences.
The study — "Not ...
AUDIO:
Drugs that are used to treat Type 2 diabetes also can contribute to unwanted side effects. But now, working with mice, researchers, led by scientists at Washington University School of...
Click here for more information.
Drugs for type 2 diabetes can contribute to weight gain, bone fractures and cardiovascular problems, but in mice, an investigational drug appears to improve insulin sensitivity without those troublesome side effects, researchers at Washington University ...
Over the weekend of June 2 and 3, Typhoon Mawar skirted the east coast of the Philippines bringing heavy surf, heavy rainfall and gusty winds that led to several missing and injured people. NASA's TRMM satellite and Aqua satellite showed heavy rainfall and cloud extent of the storm.
On June 1, Mawar (known as Ambo in the Philippines) had maximum sustained winds near 45 knots and it was about 245 miles east-northeast of Manila, Philippines. On that day, as Mawar continued north, some warnings were posted for the Philippines: Public storm warning signal #1 was up in the ...
ANN ARBOR, Mich.—Religious practices that strongly control female sexuality are more successful at promoting certainty about paternity, according to a study published in the current issue of the Proceedings of the National Academy of Sciences.
The study analyzed genetic data on 1,706 father-son pairs in a traditional African population—the Dogon people of Mali, West Africa—in which Islam, two types of Christianity, and an indigenous, monotheistic religion are practiced in the same families and villages.
"We found that the indigenous religion allows males to achieve ...
DALLAS – June 4, 2012 – UT Southwestern Medical Center researchers have taken a major step toward understanding the cellular clock, mapping for the first time the atomic-level architecture of a key component of the timekeeper that governs the body's daily rhythms.
The daily, or circadian, cycles guided by the body's clocks affect our ability to get a good night's sleep, how fast we recover from jet lag, and even the best time to give cancer treatments, said Dr. Joseph Takahashi, senior author of the Science study published online and a pioneer in the study of circadian ...
The RHESSI (Ramaty High Energy Solar Spectroscopic Imager) satellite focuses on the highest energy x-rays and gamma-rays produced by the sun, helping to observe solar flares of all shapes and sizes. The satellite is pointed toward the sun, and constantly in rotation, which provides a serendipitous bit of side research: by monitoring the limb of the sun on its four second rotation cycle, RHESSI's Solar Aspect System (SAS) has produced ten years worth of precise measurements of the sun's diameter. This has already provided scientists with one of the most accurate measurements ...
When Venus transits the sun on June 5th and 6th, an armada of spacecraft and ground-based telescopes will be on the lookout for something elusive and, until recently, unexpected: The Arc of Venus.
"I was flabbergasted when I first saw it during the 2004 transit," recalls astronomy professor Jay Pasachoff of Williams College. "A bright, glowing rim appeared around the edge of Venus soon after it began to move into the sun."
For a brief instant, the planet had turned into a "ring of fire."
Researchers now understand what happened. Backlit by the sun, Venus's atmosphere ...
