SAN ANTONIO — Part of a naturally made protein might speed recovery in brain tissue that gets starved of oxygen and nutrients when a blood clot lodges in the brain and causes a stroke. Researchers tested a human recombinant version of a natural protein fragment, called perlecan domain V, on rats and mice in which they induced strokes. They reported February 25 at the International Stroke Meeting that the animals recovered in three days.
Perlecan DV is a part of perlecan, a protein that resides in the spaces between cells in the brain. Neurologist Gregory Bix of Texas A&M University in College Station said he and his colleagues became interested in perlecan DV when they found levels of it elevated in tissue affected by stroke, even though other proteins in this affected region of the brain had been broken down.
Other experiments showed that rats and mice in which perlecan DV supplies were suppressed “had very bad strokes,” Bix said. “So we knew perlecan DV was important for something.”
The researchers next injected the recombinant version of perlecan DV into mice and rats that had strokes. “The animals did amazingly well,” Bix said. Those animals treated with the compounds recovered the ability to walk and had no obvious impairments, Bix said. Untreated animals remained disabled.
Although the perlecan DV was injected into the abdomens of the animals, it homed to the brain site of injury caused by the stroke. That wasn’t an accident, Bix said, because perlecan normally coats blood vessels and perlecan DV facilitates new blood vessel growth, which the brain tries to do in response to injury.
Perlecan DV also spawned growth of new neurons, Bix said. When new blood vessels sprout in the brain, the protein fragment encourages new neuron growth in the injured areas. “Baby neurons used [the vessels] like railroad tracks” to arrive and grow in the damaged spot, repopulating the cells, he said. Thus, adding perlecan DV revs up quantities of a natural pro-growth substance.
Bix hopes to license the recombinant human perlecan DV and get it tested in stroke patients.