Colitis is inflammation of the colon, also known as the large intestine. Several things can cause colitis such as infection, medication, ischemia, or chronic inflammatory bowel disease. Inflammatory bowel diseases that affect the colon, such as ulcerative colitis or Crohn’s disease, are particularly challenging for patients. It is a chronic disease that causes cramping pain, bloody diarrhea, weight loss, fatigue, and many other chronic, challenging symptoms.
Since ulcerative colitis does not occur naturally in animals, researchers sometimes use an experimental form of colitis to mimic the disease seen in humans. This experimental colitis serves as a model to investigate treatments for inflammatory bowel disease. Essentially, researchers create a situation in which mice develop a condition that looks very much like ulcerative colitis. They develop inflammation in the large intestine, along with signs of oxidative stress and cell death. Conversely, treatments for ulcerative colitis reduce or prevent inflammation, oxidative stress, and cell death in the colon of these experimental mice.
Researchers used this model of experimental colitis to study the effect of bone marrow stem cells as a treatment for colitis. More specifically, they tested the effects of a certain part of bone marrow stem cells called extracellular vesicles. Extracellular vesicles are small spheres that containing various beneficial substances. Stem cells release these vesicles into the body. A single stem cell can release hundreds of extracellular vesicles. In fact, it is the extracellular vesicles that are believed to contain many of the useful substances that are released by bone marrow stem cells such as proteins, lipids, and nucleic acids. These substances can precisely target sick and damaged cells in the body and repair them.
Impressively, when researchers used extracellular vesicles derived from bone marrow stem cells to treat animals with experimental colitis, they observed rather extraordinary results. These vesicles protected the intestines from colitis damage. Untreated animals had severely damaged intestines when viewed under a microscope, but animals treated with extracellular vesicles had nearly normal looking intestines. Treatment also substantially reduced levels of cytokines related to oxidative stress, such as IL-1β. Extracellular vesicles derived from bone marrow stem cells also apparently blocked the intestinal cells’ ability to undergo cell suicide (apoptosis).
Taken together, these results strongly suggest that mesenchymal stem cells from bone marrow, specifically the extracellular vesicles contained within them, can dramatically improve experimental colitis. While more research is needed, this study suggests that these stem cell products could one day be a useful treatment for inflammatory bowel diseases, such as ulcerative colitis and inflammatory bowel disease.