Peptide Helps Paralyzed Rats Recover Function

Brett Smith for – Your Universe Online
A spinal cord injury can be devastating and life-changing – currently with little hope for full recovery.
However, new research from a large team of North American scientists has shown promise for a compound known as intracellular sigma peptide (ISP), according to a report in the journal Nature.
Study researchers found that ISP helped lab rats with spinal cord injuries regain the ability to control urination, move or both. They added that the results could be a sign the compound could be used in the future for treating humans with similar injuries.
“This recovery is unprecedented,” study author Jerry Silver, a professor of neurosciences at Case Western Reserve University in Cleveland, said in a recent statement. “Each of the 21 animals got something back in terms of function.”
“For any spinal cord-injured patient today, it would be considered extraordinary to regain even one of these functions, especially bladder function,” Silver added. “ISP additionally has treatment potential for diseases where the body produces destructive scarring such as heart attack, peripheral nerve injury and multiple sclerosis (MS).”
When an animal suffers an injury to the central nervous system (CNS), molecules called proteoglycans collect in scar tissues at the trauma location and in the perineuronal net. In normal tissue, proteoglycans are essential factors in the connections among cells and play a major role in sustaining the framework of the nervous system.
However, after an injury, proteoglycans are extremely abundant in scar tissue and the dense nets around synapses throughout the CNS. The result is a powerful barrier keeping regeneration from taking place. Proteoglycans at these injury sites create a sticky mass, entangling and limiting the cut nerve fiber tips from forming proper connections that transmit integral signals via electrical impulses.
In the study, researchers engineered the ISP peptide to block the neuron’s proteoglycan receptor on/off switch. They also added a shuttle known as trans-activator of transcription (TAT) to send ISP throughout the CNS and through cell membranes. This allowed ISP to be delivered systemically – as opposed to with a direct injection to the spinal cord.
“Our treatment strategy was designed to be easily translatable,” said study author Bradley Lang, a graduate student in the Silver lab at Case Western. “Our goal is to progress this treatment forward for use as a therapeutic following spinal cord injury.”
The researchers used 26 severely paralyzed rats, all of which received injections every day for seven weeks. The study team tracked the rates of ability to walk, to balance and to control urination and saw 21 of the 26 animals regain one or more of the functions well after injections began.
“We don’t know why a particular animal regained a specific function,” Silver said. “That is one of the big remaining questions.”
Despite lingering questions, the researchers said they were optimistic that ISP could one day be used to treat humans with injuries to the CNS.
“We’re very excited at the possibility that millions of people could, one day, regain movements lost during spinal cord injuries,” Silver told the AFP news agency.
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