A study led by a Great Ormond Street doctor has shown that
amniotic fluid stem cells can reverse intestinal damage in rats
caused by necrotising enterocolitis -- an often fatal disorder that
afflicts premature babies.
Expert in regenerative medicine Paolo De Coppi had already
proved that amniotic fluid could be reprogrammed in a similar way
to how we reprogram embryonic stem cells, and without introducing
potentially damaging genes to instigate the transformation (how
adult cells are made pluripotent). Though not quite as versatile as
the embryonic version, De Coppi showed that they could be converted
into liver, bone and nerve cells.
What's interesting about this latest study is that the stem
cells calmed the intestinal inflammation, healed and reversed
damage done to the gut far better than bone marrow stem cells (used
in a rate control group), and in an unexpected way. After being
injected, the cells travelled to the tiny villi that line the
intestinal walls and absorb nutrients, where it then released an
unknown substance that triggered progenitor cells to calm the
inflammation and instigate tissue and villi regrowth. The team is
unsure exactly how it released a growth factor to kick the
progenitor cells into action, but it's hoping further studies could
clear this up -- that knowledge could then be used to develop drugs
that replicate the same action.
"We are still investigating," De Coppi told
Wired.co.uk, "but we know that the AFS cells by secreting
growth factors activate COX-2+ cells in the intestine which are
responsible of activating the stem cells of the epithelium of the
In the meantime, De Coppi says, "we hope that stem cells found
in amniotic fluid will be used more widely in therapies and in
research, particularly for the treatment of congenital
"We are already working on establishing a bank of amniotic fluid
stem cells," he told Wired.co.uk. "Whenever that will be ready we
could think about doing clinical trials because it is still a
disease with 40 percent mortality, with no specific therapy."
Necrotising enterocolitis is common in premature babies, with
inflammation rapidly leading to tissue death and a perforated
intestine if antibiotics have no effect. At that point, an
operation is the only option and these have a 70 percent survival
rate due to related risks of surgery at such a young age, and can
leave infants with a shortened intestine and trouble eating for the
rest of their lives. This latest study gives hope for an
injectable, non-invasive solution.
Stem cells have already been shown to have some incredible
properties for regenerative medicine -- most recently baboon
embryonic stem cells were used to repair damaged arteries. However, due the ethical grey area
embryonic experiments reside in, progress has inevitably been
slower, with the first official human trials only recently beginning to take place. Stem cells derived from amniotic fluid
have huge potential, but would mainly still rely on donors given
the impracticalities of storing fluid from every birth.
Nevertheless, according to estimates published in a 2005 study,
just 150 donors would provide a match for 38 percent of the
De Coppi, who in 2010 made headlines when he built an
11-year-old boy a trachea replacement from his own bone marrow stem
cells, is currently raising funding for his research into building rejection-free
transplants from stem cells.