Stem Cell Research

Plant Stem Cells Could Be Excellent Source Of Low-Cost Cancer Drug

Researchers have isolated and grown stem cells from a yew tree whose bark is a natural source of the anticancer compound paclitaxel. The development could enable the compound to be produced on a commercial scale at low cost, with no harmful by-products.

Scientists and engineers behind the development say the drug treatment – currently used on lung, ovarian, breast, head and neck cancer – could become cheaper and more widely available. The study was carried out by the University of Edinburgh and the Unhwa Biotech company in Korea.

Currently, an extract from yew tree bark is used to industrially manufacture the compound paclitaxel. However, this process is expensive, requires supplies of mature trees, and creates environmentally damaging by-products.

Cedars-Sinai awarded $1.9 million from CIRM to develop stem cell treatments for osteoporosis

Physicians and scientists from the Cedars-Sinai Regenerative Medicine Institute and Department of Surgery, led by Dan Gazit, DMD, PhD has been awarded a three-year $1.9 million grant from the California stem cell agency to fund research leading to clinical trials for what could become the first biological treatment for the most common type of bone fracture in osteoporosis patients.

"Vertebral fractures are a common, painful problem for adults with osteoporosis and it can cause severe back pain and disabilities," said Gazit. "Currently, there are not many effective options for treatment so our goal is to develop a biological treatment that not only promotes healing but also stimulates normal bone production."

Vertebral compression fractures account for approximately 700,000 injuries in the United States each year – twice as many as hip fractures. They often are a result of a severe jolt to the spine, or a weakening of the spine due to osteoporosis. Approximately 10 million Americans are diagnosed with osteoporosis, a condition that primarily affects older women and is characterized by decrease in bone mass that causes bone brittleness. Another 34 million Americans have low bone mass, which also increases vulnerability to vertebral compression fractures.

Medical therapy and research have focused mainly on prevention, but when compression fractures occur, the only medical interventions available involve injection of synthetic, non-biological material that does not absorb into tissues and remains a permanent foreign body fixture in the spine.

The grant will be used to conduct studies in which animals with osteoporosis and vertebral fractures are treated with intravenous injections of human adult stem cells and a hormone already approved by the FDA for the treatment of osteoporosis patients. The study is scheduled to begin in early 2011.

"We are excited about Dr. Gazit's research and grateful for the ongoing support from the California Institute for Regenerative Medicine," said Clive Svendsen, Ph.D. director of the Cedars-Sinai Regenerative Medicine Institute. "This grant will allow us to continue advancing the use of adult stem cells to the next level, which is towards clinical use in order to give renewed hope for a healthier quality of life to the millions diagnosed with osteoporosis and related disorders."

Bruce Gewertz, MD, chair of the Department of Surgery and vice-president for interventional services said, "in the future, innovative application of stem cells will likely be an invaluable tool for surgeons to foster healing in a wide range of musculo-skeletal injuries."

Adapted from the Cedars Sinai announcement.

Placental Stem Cells Successfully Treat Peripheral Artery Disease In Duke University Patient

We wouldn't post this individual success if it had taken place in some distant part of the world with researchers that aren't well known.  It didn't. It took place at Duke University where some exceptional work has been done with cord and other blood related stem cells. Here is the story as reported by television news in West Palm Beach, Florida.

Ronald Davis can move again after seven long years. Plaque clogged the artery carrying blood to his leg, which cut off oxygen flow. It's called Peripheral Artery Disease. Left alone, it can cause ulcers, gangrene and even lead to amputation.

Ronald began a last-ditch stem cell therapy at Duke University. His leg was marked for 30 injections, totaling millions of stem cells. For him, there was no other choice.

Cells are taken from the placentas of Israeli women who've given birth. Once injected, they secrete proteins, which boost additional cell growth. Then, it's believed those cells may contribute to the growth of additional vessels around the plaque, circumventing the blockage.

Three days after injections, Ronald was walking, and doctors say the oxygen level in his leg tissue jumped from 43 percent to 67 percent. This specific type of stem-cell therapy is currently involved in a phase-one clinical trial. P-A-D affects up to 20-percent of people over the age of 65.

Caspase ("Grim Reaper") Genes Found To Be Gatekeepers In Adult Cell To Induced Pluripotent Stem Cell Regression

"By doing experiments in which we added caspase inhibitor genes to the Yaminaka protocol, we discovered that when caspases are turned off, you cannot make IPSCs," said Chuan-Yuan Li, PhD, professor of radiation oncology at the University of Colorado School of Medicine. "We were able to shut down the process almost completely."

Dr. Shimya Yaminaka's (Kyoto University) creation of induced pluripotent stem cells meant research to improve human disease might be able to use iPSCs in lieu of embryonic stem cells. Since then, researchers around the world have been able to replicate his process. However, no one has been able to unlock the mechanism that allows cells to be regressed from differentiated to undifferentiated cells.

Now, Li, and fellow researchers have discovered that so-called "grim-reaper" caspase genes are the gatekeepers that can open the door to allow differentiated adult cells to regress to undifferentiated iPSCs.

Ticking of a Cellular Clock Promotes Seismic Changes in the Chromatin Landscape Associated with Cell Aging

Unlike embryonic stem cells, adult human cells have a finite number of lives. Once they divide a certain number of times, they change shape, slow their pace, and eventually stop dividing, a phenomenon called "cellular senescence."

Biologists know that a cellular clock composed of structures at the chromosome end known as telomeres records how many "lives" a cell has expended. Up to now, researchers have not defined how the clock's ticking signals the approach of cellular oblivion.

Now, researchers report that as cells count down to senescence and telomeres wear down, their DNA undergoes massive changes in the way it is packaged. These changes likely trigger what we call "aging."

"Prior to this study we knew that telomeres get shorter and shorter as a cell divides and that when they reach a critical length, cells stop dividing or die," said Jan Karlseder, Ph.D., associate professor in the Molecular and Cell Biology Laboratory at the Salk Institute for Biological Studies. "Something must translate the local signal at chromosome ends into a huge signal felt throughout the nucleus. But there was a big gap in between."

Karlseder and postdoctoral fellow Roddy O'Sullivan, Ph.D., began to close the gap by comparing levels of proteins called histones in young cells—cells that had divided 30 times—with "late middle-aged" cells, which had divided 75 times and were on the downward slide to senescence, which occurs at 85 divisions. Histone proteins bind linear DNA strands and compress them into nuclear complexes, collectively referred to as chromatin.

Karlseder and O'Sullivan found that aging cells simply made less histone protein than do young cells. "We were surprised to find that histone levels decreased as cells aged," said O'Sullivan. "These proteins are required throughout the genome, and therefore any event that disrupts this production line affects the stability of the entire genome."