Adult Stem Cells Treat Pulmonary Fibrosis

American Journal of Pathology, June 4, 2009

In acute respiratory distress syndrome, inflammation and fibrosis result in loss of lung tissue which, according to a recent study, may be treated by mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are known to produce a number of growth factors and have been shown to inhibit fibrosis in liver failure as demonstrated by Parekkaden et al. in 2007, and to differentiate into pulmonary cells as reported by Sueblinvong et al. in 2007. Additionally, bone marrow mononuclear cells, which contain both hematopoietic stem cells and MSCs, have been used to treat pulmonary hypertension in an animal model. Now, scientists have tested the therapeutic capacity of MSCs derived from Wharton's Jelly in an animal model of lung fibrosis.

Led by Dr. Yuben Moodley, scientists in Australia have reported the results of their study in a paper entitled "Human Umbilical Cord Mesenchymal Stem Cells Reduce Fibrosis of Bleomycin-Induced Lung Injury". The scientists obtained Wharton's jelly from human umbilical cords derived from full-term, live, healthy births, from which the mesenchymal stem cells (MSCs) were then separated and administered to a mouse model of bleomycin-induced lung injury. Lung tissue was evaluated at one, two and four weeks post-bleomycin, from which the researchers observed that the MSCs were found to have migrated only to those areas of inflammation and fibrosis but not to healthy tissue.

As the scientists describe in their paper, the administration of the MSCs reduced inflammation and inhibited the expression of various signaling chemicals which contribute to inflammation, including a number of proinflammatory cytokines. The scientists therefore concluded that MSCs "have antifibrotic properties and may augment lung repair if used to treat acute respiratory distress syndrome."

A glycopeptide antibiotic that is produced by the bacterium Streptomyces verticillus, bleomycin is commonly used in cancer chemotherapy but is well known for a number of serious side effects which include pulmonary fibrosis and other types of impaired lung function, due to the role of bleomycin in producing a number of proinflammatory cytokines and inducing oxygen toxicity.

Wharton's jelly, named after the 17th century anatomist Thomas Wharton, is the gelatinous, mucosal substance found within the umbilical cord and is a rich source of hyaluronic acid, chondroitin sulfate and adult stem cells, among other substances.