Tissue that is typically discarded in routine hip replacement operations may offer a rich untapped source of stem cells that could be banked for later use in regenerative medicine, where patients' own cells are used to treat disease or repair failing organs.
This was the implication of a new study led by the University of New South Wales (UNSW) in Australia, published online recently in the journal Stem Cells Translational Medicine.
Study leader Prof. Melissa Knothe Tate and colleagues say, given the tens of thousands of hip replacements performed every year, their findings could have "profound implications" for clinical use.
Currently, to grow new bone or tissue after an infection, injury or the removal of a tumor, if the patient has not preserved stem cells in a cell bank (which is the case for the vast majority of older adults), the stem cells have to come from a donor, or the patient has to undergo surgery to have them harvested from their own bone marrow.
Prof. Knothe Tate explains how their study findings, which now need to be tested clinically, could offer a new source of stem cells for older patients:
"In hip replacement surgery, the femoral head and part of the neck are resected to accommodate the neck of the implant. Typically this tissue is discarded, yet it may provide an untapped source of autologous stem cells for ageing adults who were born a generation too early to benefit from banking of tissues like umbilical cord blood at birth."
Discarded hip replacement and bone marrow stem cells 'remarkably similar'
For their study, the team collected periosteum derived stem cells (PDCs) from rheumatoid arthritis or osteoarthritis patients aged between 30 and 72 years who had undergone joint replacement surgery. The periosteum is the membrane that covers the outer surface of bone.
When they compared the PDCs with commercially available bone marrow stem cells cultured under the same lab conditions, they found "remarkable similarities."
The PDCs showed no significant differences to the bone marrow stem cells in their ability to differentiate into other cells, regardless of donor age or disease.
The researchers conclude that the periosteum tissue normally discarded in hip replacements offers an "unprecedented and to date unstudied source of stem cells from rheumatoid arthritis or osteoarthritis patients."
Meanwhile, researchers from the US and Japan reported successfully creating embryonic stem cells without embryos. Writing in the journal Nature, they describe how they changed adult stem cells back to their original embryonic state by exposing them to low oxygen and acidic environments.
Written by Catharine Paddock PhD