Stem cell treatments being promised in
mainland China are "21st century snake oil" scam., according to two pediatric eye
surgeons at Washington University School of Medicine in St. Louis .
Recent newspaper stories - including
several from Missouri -- have reported parents flying their children to main land China for
umbilical cord stem cell (CSC) infusions. The cost of these treatments, paid
for entirely out-of-pocket by the parents, can be $50,000 or more. CSCs are
extracted from the umbilical cords of Chinese mothers and their newborns and
injected into the fluid around the spinal cord of the American children. The
parents are led to believe by Chinese doctors that these CSCs are an effective
treatment for optic nerve hypoplasia (ONH), a disease causing partial blindness
ONH is growth failure of one or both optic
nerves during the first trimesters of pregnancy. The nerve is the "cable"
connecting the eye to the brain and each nerve should have one million fibers;
in ONH the number of fibers ranges from 200,000-800,000. ONH, which affects
about 1 in 5,000 newborns, is not hereditary and the exact cause is unknown.
Lawrence Tychsen, M.D., and Gregg Lueder,
M.D., professors of ophthalmology and visual sciences at Washington University
School of Medicine and pediatric ophthalmologists at St Louis Children's
Hospital, diagnose and treat dozens of children each year with ONH. They are
concerned that the CSC reports will mislead many parents of children with ONH,
who may bankrupt savings, go deeply into debt or organize fundraisers to pay
for sham treatment.
Although some parents claim improvement in
their child's vision after returning from China,
Tychsen and Lueder caution that no objective visual gains after CSC treatment
have been demonstrated in any child with ONH. They can measure visual
improvements objectively in infants and toddlers using non-invasive nerve and
brain imaging and electronic measures of visual brain activity. They add that
one would expect "a powerful placebo effect after these purported treatments.
The temptation to believe vision had
improved, after the expenditure of so much time and money, would be difficult
to resist." Aside from grave ethical concerns, they say that the injections
could be dangerous, introducing infection or toxic matter into the brain
Tychsen, who is also a neurobiologist
studying visual brain development in infant monkeys, listed a number of reasons
to disbelieve reports of improvement. First, CSCs placed in human spinal fluid
would not be transported into the fibers of the optic nerve. Second, CSCs have
never been shown to transform into optic fibers, even in fish or rodent
experiments. In a monkey or human, the task would be "several orders of
magnitude more complex," Tychsen said. Third, to improve vision, 100,000 or so
fibers would need to grow, not just a few, and each of the fibers would need to
connect precisely in the brain.
"CSCs are used legitimately throughout the United States to treat blood diseases (such as leukemia) when the donor and
recipient are genetically matched," Tychsen said. "But CSCs from an unrelated
person are rejected and destroyed. Even if an unmatched CSC survived, found its
way inside the optic nerve and transformed itself into a new fiber, the fiber
would need to find the correct connection among more than 500,000 connections
in the visual brain.
Such a series of events would be so
improbable as to qualify as miraculous, the equivalent of a chimpanzee typing
the five acts of King Lear at one sitting," Tychsen said. He said he believes
that experiments by neuroscientists devoted to the discovery of nerve growth
molecules may hold the best hope for future cures.
Lueder pointed out that parents of ONH
children should not despair.
"Many babies born with ONH will have some
improvement as they mature, because they learn to exploit more effectively the
optic fibers that remain," he said. Children with ONH can also achieve some
improvements with surgery for eye crossing and nystagmus (roving movements of
the eyes). He added that many ONH children function reasonably well in school
using enlarged print, magnifiers and other aids for the visually impaired.