Monday, 21 November 2011
Immune system can abort stem cell regeneration
The immune system`s T-cells, which protect our body from invading pathogens and illnesses, can also abort stem cells from regrowing bone and tissue, a key factor in bone regeneration.
The study, conducted by the Centre for Craniofacial Molecular Biology of the University of Southern California, examined how mice with genetic bone defects responded to infusions of bone marrow stem cells, or BMMSC.
Under normal conditions, the mice`s T-cells produced an inflammatory response, triggering the creation of cellular proteins, interferon (INF) and tumour necrosis factor (TNF)-alpha, which killed the stem cells, preventing the production of new bone, reports the journal Nature Medicine.
Stem cells are found in all multi-cellular organisms that can divide and differentiate into diverse specialized cell types of muscles, tissues and bones and can self-renew to produce more stem cells.
"Normally, T-cells protect us from infection but they can block healthy regeneration from happening," said Songtao Shi, professor at the Centre and study author, according to a California statement.
However, when the mice were given infusions of regulatory T-cells, or Treg -- specialized subpopulation of T-cells -- the levels of the interfering proteins decreased, increasing bone growth and defect repair.
Furthermore, administering the anti-inflammatory drug aspirin at the site of the bone defect also increased the rate at which the stem cells were able to regrow bone.