Doctors at the Casey Eye Institute at Oregon Health & Science University in Portland have announced the first-ever use of the revolutionary gene editing tool, CRISPR, inside of a person’s body. The tool was used to modify the genes responsible for a particular form of inherited blindness, and those responsible for the pioneering effort say there is real potential here to not only restore the patient’s vision, but open up a new line of medicines specifically used to target and alter DNA.
In an Associated Press report, which comes via NBC, the companies that make the treatment used in the procedure, including Cambridge, Massachusetts-based Editas Medicine and Dublin-based Allergan, highlighted the possibilities moving forward if the trial proves to be successful. Charles Albright, chief scientific officer at Editas, said that “We literally have the potential to take people who are essentially blind and make them see.”
Scientists at the OHSU @CaseyEye Institute have injected a harmless virus containing #CRISPR gene-editing instructions inside the retinal cells of a patient with a rare form of genetic blindness.@NPR @RobSteinNews https://t.co/nZn8AjOBLV— OHSU News (@OHSUNews) March 6, 2020
The patient who underwent the treatment suffers from Leber congenital amaurosis, which is an eye disorder that affects the retina, and usually causes “severe visual impairment beginning in infancy.” The disorder is caused by a gene mutation that prevents the body from producing the proteins present in the eye that are necessary for converting light into the brain signals that enable sight.
The hour-long procedure, performed with the patient under general anesthesia, was executed by dripping drops of fluid containing the CRISPR DNA sequences through a hair-wide tube into the linings in the back of the patient’s eyes, which house the light-sensing cells necessary for vision. (Note that it is this fact, that the procedure was done in vivo, that makes this CRISPR breakthrough stand apart from other recent ones in the human-cell arena.)
The first-ever in vivo CRISPR gene edit procedure. OHSU/Kristyna Wentz-Graff
For those unfamiliar, CRISPR, or “clustered regularly interspaced short palindromic repeats,” is a family of DNA sequences found in the genomes of bacteria. Essentially, CRISPR is the defense mechanism that a bacterium uses to guard against bacteriophages, or viruses that attack bacteria. If a bacterium is able to survive an attack from a bacteriophage, it will store some of its DNA; if the same type of bacteriophage attacks the bacterium, the latter uses a protein to check the new attacker’s DNA. If it matches the bacteriophage DNA “on file,” the protein “clips” it out of the bacterium’s genome, rendering it harmless.
As it turns out, it’s possible to take this bacterium defense mechanism and “program” it by feeding it DNA sequences. I.e., scientists are able to take this bacterium defense system, program it with a DNA sequence they wish to have removed from a particular genome, and then inject it (via a harmless virus) into target cells, who then have their DNA altered.
A short CRISPR explainer video.
The doctors involved with the procedure say that there is little risk for the patient in this case, because the type of cells affected do not divide. There are still other dangers with CRISPR, however, including the possibility of making unintended changes to a genome, as well as the possibility of unwanted genetic alterations being passed on to future generations.
Ultimately, it seems that those involved with this CRISPR breakthrough see this operation, should it prove to be successful, as a solid first step toward performing more in vivo CRISPR alterations. In fact, Dr. Jason Comander, an eye surgeon at Massachusetts Eye and Ear in Boston—which also plans to conduct the procedure on patients—told the Associated Press that this kind of technology is likely to usher in “a new era in medicine.”
What do you think about this first-ever in vivo use of CRISPR? Give us your hot takes on this cool tech in the comments!