(c) Albert Edge/Mass. Eye and Ear
正常な蝸牛では，有毛細胞は外側に3列，内側に1列見られる
マウスを使った実験で，聴覚を担う有毛細胞の再生に成功した。難聴のうち最も一般的な感音難聴は，内耳にある有毛細胞が騒音，感染，薬剤などにより失われることが原因となる。哺乳類の有毛細胞は自然に再生しないため，治療により聴覚を取り戻すのは困難だ。実験で使われた薬剤は，耳に由来する幹細胞に加えた場合，その刺激で有毛細胞を再生させることができる。難聴のマウスの耳にこの薬剤を投与したところ，有毛細胞の再生と聴覚の改善が認められた。哺乳類の成獣で有毛細胞が再生できたのは初めてのことだ。（吉田素子）
Hearing Restored after Noise Damage
In Promising Therapy for Deafness, Hair Cells Regrown in Ears of Mice
Researchers at Massachusetts Eye and Ear and Harvard Medical School have demonstrated for the first time that hair cells can be regenerated in an adult mammalian ear by using a drug to stimulate resident cells to become new hair cells, resulting in partial recovery of hearing in mouse ears damaged by noise trauma. This finding, reported in the Jan. 10 issue of Neuron, holds great potential for future therapeutic application that may someday reverse deafness in humans.
“Hair cells are the primary receptor cells for sound and are responsible for the sense of hearing,” explains senior author, Albert Edge, HMS associate professor of otology and laryngology at Mass. Eye and Ear. “We show that hair cells can be generated in a damaged cochlea and that hair cell replacement leads to an improvement in hearing.”
Hearing loss is a significant public health problem affecting close to 50 million people in the United States alone. Sensorineural hearing loss is the most common form and is caused by the loss of sensory hair cells in the cochlea. Hair cell loss results from a variety of factors including noise exposure, aging, toxins, infections, and certain antibiotics and anti-cancer drugs. Although hearing aids and cochlear implants can ameliorate the symptoms somewhat, there are no known treatments to restore hearing, because auditory hair cells in mammals, unlike those in birds or fish, do not regenerate once lost. Auditory hair cell replacement holds great promise as a treatment that could restore hearing after loss of hair cells.
［単語和訳］
Hearing：聴覚
Therapy：治療 Deafness：難聴 Hair Cells：有毛細胞 Regrown：再生した Mice：マウス
Researchers：研究者 be regenerated：再生される mammalian：哺乳類の stimulate～to…：～を刺激して…させる resident：常在の resulting in：結果として～となった noise trauma：騒音外傷 Neuron：ニューロン（Neuronは雑誌名） holds great potential for：～の重要な可能性を秘めている therapeutic：治療的
receptor cells：受容細胞 are responsible for：～を担う the sense of hearing：聴覚 senior author：主席著者 associate professor：准教授 otology：耳科学 laryngology：喉頭科学 be generated ：生成される cochlea：蝸牛
Hearing loss：難聴（聴力損失） public health：公衆衛生上の close to：ほぼ Sensorineural hearing loss：感音難聴 sensory hair cells：感覚有毛細胞 results from：～に起因する a variety of：様々な noise exposure：騒音曝露 aging：加齢（老化） toxins：毒素 infections：感染 antibiotics：抗生物質 anti-cancer drugs：抗がん剤 hearing aids：補聴器 cochlear implants：人工内耳 ameliorate：～を改善する symptoms：症状 auditory hair cells：聴覚有毛細胞 mammals：哺乳動物 unlike：～とは異なり holds great promise as：～としてかなり有望である
