Beneath greying dreadlocks,
50-year-old Lily Heppner's cheerful sunburnt face glistened
with a slick covering of aloe vera gel as she expounded
upon the virtues of the slimy goo inside the leaves of
these remarkable plants. "Aloe vera has been touted for
its therapeutic properties for thousands of years," she
said. But the plant is only now receiving recognition
from the established medical community as a potential
lifesaver. Researchers from the University of Pittsburgh's
McGowan Institute for Regenerative Medicine reported in
the August issue of Shock that the use of an aloe
vera-based resuscitation fluid improved the survival rate
of rats following massive blood loss.
The drastic fall in blood pressure
that follows severe blood loss can be lethal. The research
holds out hope that soldiers in the battlefield — the
focus of the project — as well as trauma victims might
be stabilized long enough to get lifesaving medical
attention. Rats in the study were bled for 25 minutes.
The considerable (2.45mL/100g) or severe (3.15mL/100g)
blood loss conditions induced hemorrhagic shock. Five
minutes after bleeding was started, rats were resuscitated
with an injection of saline or of saline containing
the aloe vera fluid. In addition, some rats that underwent
severe blood loss received no fluid at all.
When bleeding was merely considerable
but not severe, five of 10 rats receiving saline survived
for four hours. However, eight of 10 rats receiving
the aloe vera fluid survived. Similarly, this treatment
also boosted survival after severe blood loss. In this
case, five of 15 rats given the aloe vera treatment
survived for two hours, whereas one solitary rat of
the 14 who were resuscitated with pure saline lived
for two hours. Those unfortunates who did not receive
any fluid died within 35 minutes.
The protection from the aloe vera
goo likely rests with its ability to cut down on turbulence
and help blood flow in a smoother, more orderly way,
according to lead author Dr Mitchell Fink. "We think
the polymer reduces the [turbulence] associated with
moving blood through the microvasculature. Thus, despite
inadequate circulating volume, the blood can more effectively
deliver oxygen to the tissues," he said.
Unfortunately, the way aloe vera
protects also involves potential risks. The reduced
turbulence could translate into decreased blood coagulation
although Dr Fink maintained that "limited experiments
suggest that excessive bleeding is not likely to be
an issue." Nonetheless, "questions related to potential
toxicity will need to be carefully addressed using very
formalized toxicity testing protocols," said Dr Fink.
"In addition, the exact composition of the polymer will
need to be established in order to guarantee that composition
remains constant from batch to batch." Only then can
human tests be done.
The research was undertaken to
develop a small volume resuscitation fluid for use in
the battlefield to, in Dr Fink's words, "buy an hour
or two for an injured soldier or other trauma victims"
when conventional treatment is impossible. Other possible
applications might one day include stroke, myocardial
infarction and peripheral vascular disease.