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Many doctors tell patients and families that recovery does not occur
after spinal cord injury. This is not true. Recovery is the rule, not
the exception after spinal cord injury.
• Segmental
recovery. Most patients recover 1-2 segments below the injury site,
even after so-called “complete” spinal cord injuries. For
example, a person with a C4/5 injury may have deltoid function on
admission and then recover biceps (C5), wrist extensors (C6), and
perhaps even triceps (C7) after several months, and the associated
dermatomes.
• Recovery due to methylprednisolone. The
second National Acute Spinal Cord Injury Study (NASCIS 2) showed that
patients with “complete” spinal cord injuries and who did
not receive the high-dose steroid methylprednisolone recovered on
average 8% of motor function they had lost. If they received
methylprednisolone within 8 hours after injury, they recovered on
average 21% of what they had lost. In contrast, people with
“incomplete” spinal cord injury recovered on average 59% of
motor function and 75% if treated with high dose methylprednisolone.
•
Recovery of postural reflexes. Most people with cervical or upper
thoracic spinal cord injury are initially unable to control their trunk
muscles. However, most will recover better trunk control over months or
even years after injury.
• Walking quads and paras. Most
people with “incomplete” spinal cord injuries, i.e. ASIA C,
will recover standing or walking. Walking recovery after
“complete” spinal cord injuries, i.e. ASIA A, are rare but
can occur in 5% of the cases. In the 1980’s, less than 40% of
spinal cord injuries admitted to hospital were
“incomplete”. However, in the 1990’s, over 60% of
spinal cord injuries are “incomplete” and thus the
incidence of “walking quads” or “walking paras”
may be higher than most people think.
Both animal and human
studies indicate that as little as 10% of spinal cord tracts can
support substantial function, including locomotion. People often can
walk even though a tumor has damaged 90% of their spinal cord. This is
due to the redundancy and plasticity of the spinal cord. Multiple
spinal pathways serve similar or overlapping functions. Plasticity
refers to the ability of axons to sprout and make new connections.
Because transected spinal cords are rare, most people have some spinal
axons crossing the injury site. This is the basis of the hope that even
slight regeneration of the spinal cord will restore substantial
function.
Experimental Therapies for Subacute Spinal Cord Injury
Several
experimental therapies are being tested in clinical trial for spinal
cord injury during the first days or weeks after injury. More
information is available in the Clinical Trial Forum on the CareCure
site.
• Monosialic ganglioside (GM1, Sygen). In 1991, Fred
Geisler and colleagues reported that GM1 injected daily for 6 weeks
after injury improve locomotor recovery 37 patients. Fidia
Pharmaceutical subsequently tested this therapy in a large multicenter
clinical trial in 800 patients, showing that the GM1 accelerated
recovery during the first six weeks but did not significantly improve
the extent of recovery at 6-12 months after injury. Note that this
trial is no longer active. Although the drug is still available in
Europe and South America, the company Fidia has been bought by another
company. CareCure Forum (GM1) Link
• Activated macrophage
transplants. In 1998, Michal Schwartz at the Weizmann Institute
reported that activated macrophages obtained from blood and
transplanted to the spinal cord improve functional recovery in rats.
The company Proneuron initiated phase 1 clinical trials to assess
feasibility and safety of macrophage transplants in human spinal cord
injury. Preliminary reports suggest that the treatment is feasible and
safe. All the patients had “complete” thoracic spinal cord
injury and received macrophage transplants within 2 weeks after injury.
Three of the 8 patients recovered from ASIA A to ASIA C, more than the
expected 5%. A phase 1 clinical trial is continuing at Erasmus Hospital
in Brussels, Belgium. A phase 2 trial is being planned in two U.S.
centers including Craig Hospital in Denver (CO) and Mt. Sinai in New
York City (NY). CareCure Forum (Macrophage) Link
•
Alternating Current Electrical Stimulation. In 1999, Richard Borgens
and colleagues at Purdue University reported that alternating currents
applied to dog spinal cords stimulated regeneration and recovery of
function in dogs with spinal cord injury. A clinical trial has
commenced at Purdue University for people who are within 2 weeks after
acute spinal cord injury. CareCure Forum (AC Stim) Link
•
AIT-082 (Neotrofin). This is a guanosine analog that can be taken
orally and reportedly increases neurotrophins or neural growth factors
in the brain and spinal cord. Neotherapeutics tested this drug in
patients with Alzheimer’s disease. They started a multicenter
clinical trial at Ranchos Los Amigos in Downey (CA), Gaylord Hospital
in Wallingford (CT), and Thomas Jefferson Hospital in Philadelphia. The
treatment must be started within 2 weeks after spinal cord injury.
CareCure Forum (AIT-082) Link
Experimental Therapies for Chronic Spinal Cord Injury
Several
therapies are being tested in clinical trials for chronic spinal cord
injury, i.e. people whose neurological recovery has stabilized one or
more years after injury. Many other treatments are being considered for
clinical trial (see article on Advances in Spinal Cord Injury Therapy
25 November 2002).
• 4-aminopyridine (4-AP). This drug is a
small molecule that blocks fast voltage sensitive potassium channel
blockers. The drug can be obtained by physician prescription from
compounding pharmacies in the United States. In addition, Acorda
Therapeutics is carrying out a multicenter phase 3 clinical trial of a
sustained release formulation of the drug in people who are more than
one and a half years after “incomplete” spinal cord injury.
The drug may improve conduction of demyelinated axons in the spinal
cord and preliminary clinical trial results suggest that the drug may
reduce spasticity and improve motor or sensory function in as many as a
third of people with chronic spinal cord injury. See CareCure Forum
(4-AP) Link
• Fetal porcine stem cell transplants.
Embryonic stem cells have attracted much attention. Several studies of
human fetal cell transplants have been carried out in Sweden, Russia,
and the United States, showing that transplanted fetal cells will
engraft in human spinal cords. However, due in part of the lack of
availability of adult human stem cells for transplantation and politics
associated with the use of embryonic human stem cells, the first and
only stem cell therapy trial for spinal cord injury in the United
States used fetal stem cells from pigs. A phase 1 clinical trial at
Washington University in St. Louis (MO) and Albany Medical Center in
Albany (NY) has transplanted fetal stem obtained from pig fetuses and
treated with antibodies to reduce the immune rejection. Sponsored by
Diacrin, this trial is aiming to test 10 patients. See CareCure Forum
(Diacrin) Link
• Olfactory ensheathing glial transplants.
Olfactory ensheathing glia (OEG) reside in the olfactory nerve and the
olfactory bulb. They are believed to be why the olfactory nerve
continuously regenerates in adults. OEG cells are made in the nasal
mucosa and migrate up the nerve to the olfactory bulb. Several
laboratories have shown that OEG transplants facilitate regeneration of
the spinal cord. Three clinical trials have started in Lisbon
(Portugal), Brisbane (Australia), and Beijing (China). In Lisbon, they
are transplanting nasal mucosa obtained from the patient into the
spinal cord. In Brisbane, they are culturing OEG cells from nasal
mucosa and transplanting the cells to the spinal cord. In Beijing, they
are culturing OEG from human fetal olfactory bulbs and transplanting
into the spinal cord. See CareCure Forum Link (Brisbane) and CareCure
Forum Link (Beijing)
Summary
Spinal cord injury is
devastating, not only for the injured person but for families and
friends. While much information is available on Internet, most of the
material is scattered and out of date. This article summarizes answers
to some of the most frequently asked questions by people who are
encountering spinal cord injury for the first time. Spinal cord injury
disconnects the brain from the body. This leads not only to loss of
sensation and motor control below the injury site but may be associated
with abnormal activities of the spinal cord both above and below the
injury site, resulting in spasticity, neuropathic pain, and autonomic
dysreflexia. Many functions of our body that we take for granted, such
as going to the bathroom, sexual function, blood pressure and heart
rate, digestion, temperature control and sweating, and other autonomic
functions may not only be lost but may be abnormally active. Finally,
contrary to popular notions about spinal cord injury, recovery is the
rule and not the exception in spinal cord injury. The recovery takes a
long time and may be slowed down or blocked by the muscle atrophy and
learned non-use. Finally, there is hope. Many therapies have been shown
to regenerate and remyelinate the spinal cord. Some of these are now in
clinical trials and many more should be in clinical trial soon.
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