Millions of tiny sensory heir cells in the inner ear enable you to hear. Age-related hearing loss involves the death of some of these sensory hair, nerve and membrane cells. Since the hair and nerve cells do not regenerate in humans, their death leads to permanent hearing loss.
Researchers in the USA have now, with the help of research on mice, found out that these sensory hair cells can be destroyed if the so-called mitochondrial membrane, which protects the cells, is destroyed. This can occur if there is too much Bak protein present. Should this happen, proteins can find their way into the cells and break them down, causing the cells to die. Bak is typically induced by oxidative stress and its levels increase as people age.
So if oxidative stress triggers damage and death of hearing-related cells, enhancing the antioxidant defences of the mitochondria should reduce such damage, says postdoctoral researcher Jinze Xu, one of the researchers behind the study.
The studies with the mice show, that older mice without Bak protein have the same good hearing as young mice.
It is estimated that in the USA alone more than 28 million Americans will be affected by the condition by 2030.
Source: www.eurekalert.org, www.pnas.org