Curing Deafness Is Within Earshot

The PNAS organization, Proceedings of the National Academy of Sciences of the United States of America, conducted research that could be used to cure deafness. In the article, Dual AAV-mediated gene therapy restores hearing in a DFNB9 mouse model, scientists discuss the process of using gene therapy to reverse certain patterns of deafness in mice. Obviously, if this research continues to be successful and is transferable to humans, as hypothesized, it could be an amazing breakthrough for both the scientific community and those affected by deafness.

It is known among scientists that most deafness is caused by autosomal recessive genes, while there are treatments and procedures to help improve hearing the best solution seems to be hidden in the genome as well. Current conventional treatments mostly rely on hearing aids and similar devices. However, these devices have their limitations, specifically the ability to distinguish speech in a noisy setting or the full perception of music. These devices improve the ability to process sound waves but that is not enough to fully replace the natural listening process. Humans especially rely on their hearing to communicate and to enjoy music, think about how devastating it is to not be able to share in an experience as common as enjoying music. This is why the idea of curing deafness on a genetic level is so significant. AAV’s, Adeno-associated viruses, are the vessels that these researchers are utilizing to transfer the proper gene into the organism to fix its hearing. This technique has never been used before but has been successful in mice and is currently in stage two of human trials. While this spreads the hope of a promising genetic future it raises concerns in the present. Physicians are left with a small window to treat the patient when this becomes an approved procedure. The best results were recorded when the treatment was admitted before the faulty genetic sequence had devolved, either before birth or as immature as possible. This raises an issue for physicians because they need ample time to diagnose the illness and then act upon it. Another issue these researchers faced was overcoming the limited space of the Adeno-associated virus. While the AAV has several positive attributes to make it the most promising vessel, its relatively small carrying capacity is causing problems for scientists. DNA is comprised of two strands, a 5’ strand, and a 3’ strand, both of these strands are necessary for the proper coding and replication of genes. The problem with the AAV is that the vessel can only carry one strand per vessel. This is obviously not ideal but scientists are tackling this problem by utilizing a double Adeno-associated virus technique. By pairing the two vectors researchers created enough carrying capacity to deliver both DNA strands simultaneously; so far this tactic has proven suitable for treatment in mice and jas moved on to clinical trials.

How exactly does this gene therapy work? The Adeno-associated virus delivers the proper genome to the inner ear and either prevents a malicious genome sequence or could repair an already formed genome sequence. The possibility of editing the genome after it has already taken effect on the organism is the most complex yet rewarding segment of this research. Gene editing has been discussed and debated profusely over the years. Scientists have made major breakthroughs in the past years using the CRISPR enzyme, a bacterial enzyme that is used to cut specific genetic sequences and replace them with others, and other revolutionary tactics. This Adeno-associated virus is yet another step towards making gene editing a common practice among physicians. While scientists focus on the positive aspects of genetic editing the public questions the morality and safety of genetic editing procedures. The public debate revolves around whether or not gene editing is safe and if we, as humans, are responsible enough to wield such power. Gene editing places the ability to change an organism at the fundamental level of their existence. Frivolous use of these abilities or even malpractice during a physicians operation could end in devastating deformities and fatal alterations. The stakes are very high with gene editing procedures, such as with cardiovascular procedures or brain surgery. A simple mistake would completely change the DNA of the organism leading to untold effects. However, the benefits of genetic editing are also significant. Genetic editing is the gateway to curing a plethora of genetic-based illnesses such as deafness. While the fear of gene editing is well deserved is it more ethical to continue to let people suffer through their illnesses when there is a method to cure them? GMO’s, genetically modified organisms, is a perfect example of a current debate centered around genetic modification. Genetically modified food is not natural and for this reason, it is seen as dangerous; The public yet remains skeptical about the effects of consuming food that was modified by scientists. Yet, genetically modified food is advantageous because it enriches food with nutrients that were not naturally there. This is useful because it allows staple crops, such as rice, to be a cheap source of nutrients that may not have previously been so easily attainable. The idea behind genetically modified food is directly related to the research discussed in this article. The curing of deafness is a huge reward and inspires the hope of those affected by autosomal recessive deafness and others impacted by genetic abnormalities, but only if used properly.

The results of the research article are very promising. One injection of the Adeno-associated virus successfully transferred the DNA into the mice and the genetic code was found being replicated, meaning that the AAV was recognized, accepted, and expressed. The scientists were able to monitor the expression of the gene by adding a genetic sequence that would be fluorescent when looked upon by the scientists. The researchers found that after eight weeks the genetic sequence was detected in sixty percent of the ear cells. By the time of full development, eighty percent of the mice had restored hearing. While the study is still not perfected this is an encouraging start towards implementing and eventually mastering similar procedures to heal human illnesses.

The scholarly article was written very professionally, obviously intended to be read by other specialists doing similar research. This is evident based on the tone and diction utilized throughout the article. The diction used throughout is comprised mostly of scientific terms suggesting that the audience would need at least some background in biology, specifically genome studies. Ideas such as recessive alleles, phenotypes, and gene expression are a necessary background to assure that the audience fully understands the article. A thorough understanding of the article is especially important for the methods section. The methods section is dense and filled with challenging scientific concepts.

An audience would be interested in this research because this is an illness that affects a large range of people. Also, the process of curing illness through the successful use of gene therapy is a very promising prospect in which the public could be interested in. Gene therapy is often discussed among society for its promising effects but also occasionally debated in a moral sense, making this procedure a topic of interest.

References

Akil O, Dyka F, Emptoz A, Lahlou G, Nouaille S, Jacques Boutet de Monvel J-PH, Hauswirth WW, Avan P, Petit C, Safieddine S, et al. Dual AAV-mediated gene therapy restores hearing in a DFNB9 mouse model. PNAS. 2019 Feb 15 [accessed 2019 Mar 5]. https://www.pnas.org/content/early/2019/02/14/1817537116