Argentinian researchers announced this week in the journal PLOS biology their knowledge of laboratory regarding the effectiveness that the Phytosterol Supplement in the deafness age related.
hearing deficit associated with age is connected to a cholesterol lowering in the inner ear. The experiments of this team, led by María Eugenia Gomez-Casati, show that phytosterol supplements can improve the function of lost cholesterol and prevent sensory disorders in mice.
Scientists from CONICET, the Department of Pharmacology at the Faculty of Medicine (University of Buenos Aires), the Mercedes Medical Research Institute and the National University of Cordoba in Argentina hypothesized that hearing loss could be related to cholesterol loss outer hair cells.
The sensory cells of inner ear, called outer hair cells, amplify sounds by changing their length. As we age, these cells lose their ability to stretch in response to stress. sound vibrations They get into the inner ear, where they prevent their amplification and lead to hearing loss.
Given that cholesterol is a key factor in the stretch response and that brain cholesterol levels have recently been shown to decrease with age, the researchers hypothesized that the hearing loss might be related to a lack of cholesterol in the hair cells. so that hypothesis was tested mice.
Prestin expression in the outer hair cells of mice treated with efavirenz and efavirenz plus phytosterols.
First, the researchers measured the amount of CYP46A1 in these inner ear cells enzyme help to degrade and recycle cholesterol.
As expected, they found more CYP46A1 in the ears of the older mice than in the younger ones, and thus a reduction in cholesterol levels.
They then demonstrated the cause-effect relationship. cause hearing loss In young miceindicated by abnormal inner ear cell production caused by overactivation of CYP46A1 with a drug.
Finally, they analyzed whether the increased cholesterol level in the brain could counteract the effect of the drug.
Because cholesterol itself cannot get from the blood to the brain, the researchers used cholesterol-like plant compounds called phytosterols that can. Young mice receiving both the CYP46A1-activating drug and for three weeks phytosterols from food showed improved outer hair cell function.
Since phytosterols are found in many over-the-counter dietary supplementscould be a practical way to combat age-related hearing loss.
However, as the authors warn, the effects on hearing loss need to be tested directly in models older miceand in humans before more definitive conclusions can be drawn
Likewise, the researchers add that thanks to this work, they were able to show that aging triggers the loss of cholesterol from the sensory cells of the inner ear and that “a retroviral treatment Commonly used in patients with HIV/AIDS, the drug reproduces the cholesterol loss seen in the elderly and impairs outer hair cell function.”
Furthermore, they describe their results as “promising” because “these deficits can be partially reversed by supplementing with phytosterols”.
Gomez-Casati, ME et al. “Phytosterols reverse antiretroviral-induced hearing loss, with possible implications for cochlear aging.” PLOS biology (2023)