Tropes

www.dailymail.co.uk_sciencetech 2015 02930.txt.txt

#Have scientists found a cure for deafness? Gene therapy that restores hearing in mice could be used on humans in just five years By Ellie Zolfagharifard For Dailymail. com and Reuters Published: 18:00 GMT, 8 july 2015 Updated: 01:22 GMT, 9 july 2015 Gene therapy to treat hereditary human deafness could be available within five years. Research revealed today shows the revolutionary technique is capable of fixing faulty DNA to let genetic deaf mice hear again. Separately, a similar Novartis gene therapy trial is under way to help restore hearing in people who have become deaf through damage or disease. The latest study found that mice with genetic hearing loss could sense noises after receiving healthy copies of their faulty genes. Scientists say the mice mutated genes are similar to those responsible for some hereditary human deafness raising hopes the technique could be used on humans. Jeffrey Holt of Boston Children's said the technique still needed'tweaking 'but he hopes clinical trials will start within five to 10 years. After missteps in the late 1990s and early 2000s, when safety scares set back research, gene therapy is enjoying a renaissance. The technique has had positive clinical results recently in conditions ranging from blood diseases to blindness.''We are somewhat late in the auditory field but I think we are getting there now, 'said Tobias Moser of the University Medical center Gottingen, Germany, who was involved not in the new research.''It's an exciting time for gene therapy in hearing.''A key element in current optimism is the development of better and safer viral delivery systems for getting corrective genes into the body. In the case of deafness, this involves injecting a gene-carrying engineered virus into the inner ear. There are currently no approved disease-modifying treatments for disabling hearing loss, which affects some 360 million people, or five per cent of the world's population, according to the World Health Organisation. Hearing aids can amplify sounds, while cochlear implants turn sounds into electrical signals for the brain to decode, but these devices can't fully replicate natural hearing. Much of the hearing loss in older people is noise-induced or age-related but at least half of deafness that occurs before a baby learns to speak is caused by defects in one of more than 70 individual genes. It is these infants Swiss and U s. researchers hope to help, after showing that replacing a mutated gene improved the function of hair cells of the inner ear and partially restored hearing in deaf mice. Scientists from The swiss Federal Institute of technology in Lausanne and the Boston Children's Hospital, tested hearing in newborn mutant mice by seeing how high they jumped when startled by a noise. The team focused on a gene called TMC1 which is a common cause of human genetic deafness, accounting for 4 to 8 percent of cases. They injected viruses containing healthy genes into an engineered virus called adeno-associated virus 1, or AAV1, This virus infected the hair cells in ears of deaf baby mice, giving them working genes. Within a month, around half the mice with the mutation showed brainwave activity consistent with hearing and jumped when exposed to loud noises. Scientists say other forms of hereditary deafness could also be fixed using the same strategy. Work at Novartis is advanced more, with the first patient treated last October in an early-stage clinical trial that will recruit 45 subjects in the United states, with results due in 2017. The swiss company's product, acquired in a 2010 deal with Genvec worth up to $214 million, delivers a gene called Atoh1 that acts as a master switch for turning on the growth of inner ear hair cells that are central to hearing. Novartis research head Mark Fishman describes it as a'spare parts'approach to fixing ageing-related frailty. The process offers hope to adults whose hair cells have been damaged by excessive noise, disease or exposure to certain drugs, including some antibiotics. But it will not help the one to three babies per 1 000 born with severe genetic hearing loss in both ears.''There are a big range of deafness types needing different approaches, 'said Moser

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