Click photo to enlarge
AgResearch Invermay scientist Chunyi Li, who has isolated
the stem cells responsible for deer growing new antlers
each year in research which could have human application.
Photo by Craig Baxter.
The possibility of severed human limbs regenerating has
come a step closer following 25 years of research by a Dunedin
scientist which has isolated the cells that allow deer to grow
new antlers each year.
AgResearch Invermay scientist Chunyi Li has determined that
stem cells at the base of antler, or the pedicle, allow deer
to grow a fresh set of antlers each year.
They are the only mammal to do so.
Dr Li said it was previously thought the annual
antler-growing process was initiated by an embryonic phase,
or "dedifferentiation of mature cells", but his discovery
confirmed that hitherto unknown stem cells ran the process.
While confident the technology he used had application for
human limb regeneration, Dr Li said such an advance was many
years away and involved different research skills.
Dr Li said in a remarkable process, the stem cells in deer
pedicles were triggered each spring to form cartilage, bone,
vessels and other cells, and it was a process of triggering
such a reaction in humans that could result in limb
regeneration.
"We know, based on antler regeneration, that bone membrane
cells are crucial. If we can turn on cells [in humans] that
resemble pedicle membrane bone cells, you may be able to
deflect scar formations towards a regeneration pathway," he
said.
AgResearch applied biotechnologies manager Jimmy Suttie said,
despite claims from the Royal Veterinary College in the
United Kingdom that it had made the discovery, that honour
went to Dr Li.
"Another team from the UK has claimed to be the initial
discoverers of the role of antler stem cells. However, Dr Li
has published his work at least two years earlier than that
group."
AgResearch was in no doubt that Dr Li and his Invermay
colleagues discovered the role of stem cells in deer antler
regrowth, Dr Suttie said.
Each spring, deer start developing antlers, with growth
accelerating through the summer at up to 2cm a day.
Antlers reached their full size in autumn, but by the next
spring they were cast and the process started again.
Farmers removed the antlers in their velvet stage in spring,
with the velvet used in Asian medicine.
Dr Li said his breakthrough came when he realised an
estimated 3.3 million cells in a 2mm thick layer around the
pedicle provoked up to 20kg of antler growth in just 60 days.
"It made me ask if it was stem cells that created that
growth?"
His discovery has had little publicity so has yet to be
picked up by other scientists, but that could change when he
addresses an international conference of stem-cell
researchers in Australia later this month and another deer
research conference in Chile next year.
Stem cells
- A class of undifferentiated cells able to grow into
specialised cell types - for example, skin, muscle, bone.
- Commonly, come from two main sources: embryos (embryonic
stem cells) and adult tissue (adult stem cells).
