Bone marrow stem cells may help control bowel disease

Washington, Aug 21 : Researchers have found that infusions of a particular bone marrow stem cell seem to protect gastrointestinal tissue from autoimmune attack in mice.

A team from Massachusetts General Hospital (MGH) Centre for Engineering in Medicine reported that mesenchymal stem cells (MSCs), known to control several immune system activities, allowed the regeneration of gastrointestinal lining in mice with a genetic mutation, leading to multi-organ autoimmune disease.

"Our findings suggest that MSC therapy could become a useful treatment for inflammatory bowel disease," said Biju Parekkadan, co-author of the study.

"Several previous studies have observed these cells' ability to inhibit specific subsets of T-cells and relieve symptoms in particular autoimmune disorders. But this is the first demonstration of their ability to suppress a broad-based autoimmune reaction and protect gastrointestinal tissue."

Autoimmune disease occurs when the immune system loses control over lymphocytes or white blood cells that attack an individual's own tissues.

Treatments for these diseases - more than 80 conditions, ranging from type 1 diabetes to rheumatoid arthritis to gastrointestinal disorders like Crohn's disease - are primarily directed against symptoms; and even those that target the immune system do not completely suppress the out-of-control response.

Found in the bone marrow, MSCs give rise to tissues supporting blood cell development and secrete factors that can modulate several immune system activities. Their use has recently received FDA approval to treat severe graft-versus-host disease in children.

The current study was designed to investigate MSCs' therapeutic potential in a model of multi-organ autoimmune disease. The researchers used a strain of mice in which a genetic mutation leads to deficiency in regulatory T-cells, which suppress the activity of self-reactive immune cells, resulting in overwhelming autoimmune disease.

The mice were treated with infusions of either MSCs or regulatory T-cells, and a week later the researchers examined the effects on tissues from the pancreas, the liver and the distal ileum - the lower end of the small intestine - which are usually attacked by autoimmune reactions.

While little improvement was seen in the pancreatic or liver tissue, in four of the six MSC-treated mice, intestinal tissues appeared almost identical to those of normal mice.

The report was published in Stem Cells.