Decline of hearing ability: Indian, US experts find gene role

In a path-breaking research which may have implications for those suffering from a decline of their cognitive and hearing abilities, Indian and American experts have established the role of a specific gene in triggering such conditions.
Experts of Sir Ganga Ram Hospital and University of Louisville School of Medicine stated that the MMP-9 gene plays a major role in causing decline of cognitive and hearing functions and removal of the said gene decreases Hyperhomocysteinemia-induced cognitive and hearing dysfunctions.
Hyperhomocysteinaemia (HHcy) is a medical condition arising due to an abnormally high level of homocysteine in the blood, experts said.
"There is a role of MMP-9 in decline of cognitive and hearing functions. The ablation of MMP-9 decreases Hyperhomocysteinemia-induced cognition and hearing dysfunction. This research was carried out on mice but has large implication for humans," said Dr Seema Bhargava, lead author of the research and Senior Consultant, Department of Biochemistry, Sir Ganga Ram Hospital.

MMP-9 gene is a matrix metallopeptidase which helps in wound healing, cell migration, learning, memory and various other functions.
Currently, 45 per cent of adults in India between 45-92 years of age suffer from hearing impairment. Deficiency of Vitamin B-12 and folate (another form of vitamin) and high homocysteine levels have also been associated with impaired hearing in women.

"It is important to identify individuals at risk for HHcy (e.G. Elderly people)... To reduce homocysteine levels, adequate vitamin supplements should be given. However, if HHcy is already present, vitamins will take several months to reduce the concentration of homocysteine.
"Our study has advocated the role of MMP-9 inhibitors by pharmaceutical companies as a therapeutic option," Bhargava said.

The research was published in the May edition of Journal of Molecular Biology Reports.