Stem Cell Research

Diabetes Distresses Bone Marrow Stem Cells By Damaging Their Microenvironment

New research has shown the presence of a disease affecting small blood vessels, known as microangiopathy, in the bone marrow of diabetic patients. While it is well known that microangiopathy is the cause of renal damage, blindness and heart attacks in patients with diabetes, this is the first time that a reduction of the smallest blood vessels has been shown in bone marrow, the tissue contained inside the bones and the main source of stem cells.

The researchers have shown a profound remodelling of the marrow, which shows shortage of stem cells and surrounding vessels mainly replaced by fat, especially in patients with a critical lack of blood supply to a tissue (ischaemia).  This means that, as peripheral vascular complications progress, more damage occurs in the marrow. In a vicious cycle, depletion of bone marrow stem cells worsens the consequences of peripheral ischaemia.

Professor Paolo Madeddu, Chair of Experimental Cardiovascular Medicine in the School of Clinical Sciences and Bristol Heart Institute at the University of Bristol, said: “Our study draws attention to the bone marrow as a primary target of diabetes-induced damage.  The research suggests that the severity of systemic vascular disease has an impact on bone marrow causing a precocious senescence of stem cells.  More severe bone marrow pathologies can cause, or contribute to, cardiovascular disease and lead to worse outcomes after a heart attack, through the shortage of vascular regenerative cells.  Clinical evidence indicates that achieving a good control of glucose levels is fundamental to prevent vascular complications, but is less effective in correcting microangiopathy.  We need to work hard to find new therapies for mending damaged microvessels.”

Adapted from the University of Bristol announcement. Read further here.

Brain Stem Cell Development Prompted By Common Diabetes Drug

Researchers have found that metformin, a drug commonly used to treat Type II diabetes, can help trigger the pathway used to instruct stem cells in the brain to become neural (nerve) cells. Brain stem cells and the neural cells they generate play a role in the repair of the injured or degenerating brain.

“If you could take stem cells that normally reside in our brains and somehow use drugs to recruit them into becoming appropriate neural cell types," Dr. Freda Miller, Senior Scientist at SickKids and Professor in the Department of Molecular Genetics at the University of Toronto, "then you may be able to promote repair and recovery in at least some of the many brain disorders and injuries for which we currently have no treatment."

Insulin And Diet Prevent Blood Stem Cell Differentiation In The Fruit Fly

Keeping blood stem cells, or progenitor cells, from differentiating into blood cells is important as blood stem cells are needed to create the blood supply for the adult fruit fly.

Now, a new study has found that the blood stem cells are receiving systemic signals from insulin and nutritional factors, in this case essential amino acids, that helped them to maintain their “stemness."

Researchers studied the flies in the larval stage of development. To see what would happen to the blood stem cells, larvae were placed into a jar with no food and left for 24 hours. Afterward, they checked for the presence of blood stem cells using specific chemical markers that made them visible under a confocal microscope.
 
“Once the flies were starved and not receiving the insulin and nutritional signaling, all the blood stem cells were gone,” said Ji Won Shim, a postdoctoral fellow in Banerjee’s lab. “All that were left were differentiated mature blood cells. This type of mechanism has not been identified in mammals or humans, and it will be intriguing to see if there are similar mechanisms at work there.”

Uterine Stem Cells Treat Diabetes In Mice

Researchers have converted stem cells from the human endometrium into insulin-producing cells and transplanted them into mice to control the animals’ diabetes.

Endometrial stem cells were bathed in cultures containing special nutrients and growth factors. Responding to these substances, the endometrial stem cells adopted the characteristics of beta cells, cells of the pancreas that produce insulin.

The incubation process took about three weeks. During this time, the endometrial stem cells took on the shape of beta cells and began making proteins typically made by beta cells. The researchers found that some of these cells also produced insulin.

Stem Cell Versatility Controlled By Protein Alliances And Competition

Like people with a big choice to make, stem cells have a process to "decide" whether to transform into a specific cell type or to stay flexible, a state that biologists call "pluripotency.

New research has shown that different proteins called transcription factors compete and cooperate in stem cells to produce complex bindings along crucial sequences of DNA. This game of molecular "capture the flag," played in teams and amid shifting alliances, appears to be a necessary part of what determines whether stem cells retain their pluripotency and whether specialized, or differentiated, cells can regain it.

Promise of Stem Cells Derived From Fat

Fat stem cells, known as adipose stromal cells, are easily separated from fat tissue after liposuction according to University of Virginia researchers. They add that an advantage of liposuction is that it is less invasive than the process used for harvesting stem cells from bone marrow, the most prized source of adult stem cells. Adipose stromal cells are also more plentiful than bone marrow stem cells, and they are better able to tolerate harsh environments.

This last quality is particularly important. From a medical point of view, it means that adipose stromal cells can be applied under conditions that would destroy other cells. In preclinical studies, Shayn Peirce-Cottler, assistant professor of biomedical engineering, and Dr. Adam Katz,  associate professor of plastic surgery,  have used them successfully to treat chronic diabetic ulcers, open sores characterized by low levels of oxygen and high levels of bacteria.

Computational Biology Shows Greater RNA Interference (RNAi) Role In Stem Cell Differentiation

In hopes of shedding light on the process of cancer initiation, neurodegenerative disorders, diabetes and other diseases, scientists have combined forces to learn how stem cell differentiation is controlled by microRNAs.

If you haven't read our previous posts, you're already asking yourself what RNA Interference (RNAi) is.  It's a term worth getting familiar with if you're interested in the developing arena of stem cell research and its potential for regenerative medicine.

On The Horizon: The Holy Grail Of Stem Cell Research?

We are in the early and rapidly changing stage in Induced Pluripotent Stem (iPS) cell development.  Until now, most research effort has been directed toward finding a way to introduce genes into an adult cell in order to return it to an embryonic stem cell state.

The step that isn't talked about much is the next one: after the cell is returned to an embryonic state it must then be coaxed or directed to become the type of cell needed in the therapeutic process or application.  The holy grail of Induced pluripotent stem cell development would be to change an abundant adult cell into the type of cell needed in the patient's body.  And the holiest of all grails would be to do it without removing the cell from the patient. 

Diabetes: Embryonic Stem Cells Implanted Into Mice Indicate Possibilities for People With Type I Diabetes

 Novocell Inc., a San Diego, California, stem cell engineering company, "today announced data demonstrating for the first time that human embryonic stem (hES) cells can be turned into pancreatic cells capable of producing insulin in mice."  The announcement coincides with the publication in the journal Nature Biotechnology.  The company has apparently demonstrated the conversion of human embryonic stem cells into pancreatic cells that produced insulin and other pancreatic hormones in mice.