Researchers at the University of Arizona College of Medicine – Tucson have started to conduct a study to investigate the biological mechanisms that cause cataracts in the aim of developing new, nonsurgical treatments.
The National Eye Institute, a division of the National Institutes of Health, has awarded Nicholas Delamere, PhD, professor and director of the Department of Physiology, a $1.6 million grant to study the involvement of two protein ion channels – TRPV1 and TRPV4 – in the development of cataracts.
“Human cataract is frequently associated with failure of the mechanisms controlled by TRPV1 and TRPV4. The hope is that studies like this might pave the way to the development of strategies to prevent or delay age-related eye diseases,” said Dr. Delamere, who has a joint appointment as a professor of ophthalmology and is a member of the BIO5 Institute.
Dr. Delamere and his research team were the first to discover that TRPV4 and TRPV1 cooperate in a way that regulates cell function in the highly specialized cells of the eye lens.
Lens transparency requires precise maintenance of ion and water content, but the lens is made from tightly packed layers of cells that are incapable of independently maintaining ion and water homeostasis.
Protein ion channels operate as pores in the cell membrane, allowing ions such as potassium, sodium, and calcium to move in and out.
The maintenance of lens transparency is unknown to scientists; nonetheless, cataract development has been linked to the failure of biological mechanisms mediated by the protein ion channels TRPV1 and TRPV4.
TRPV1 and TRPV4 in cells on the surface of the lens operate as sensors for the control mechanisms that regulate the entire structure of the lens, including water content, size, shape, optical clarity, and focusing power, according to Dr. Delamere's previous research.
The new research will look at how small changes in hydrostatic pressure on the surface cells of the lens trigger TRPV1 and TRPV4 to allow homestasis to occur.
Dr. Delamere and his team also want to figure out how TRPV1 and TRPV4 interact with the cytoskeleton, the cell's internal foundation. The goal is to discover and understand the mechanisms responsible for age-related lens cell changes.
The research team consists of Mohammad Shahidullah, DVM, PhD, research associate professor in the Department of Physiology, and Rick Mathias, PhD, and Junyun Gao, PhD, of the Department of Physiology and Biophysics at Stony Brook University.
According to the National Eye Institute, 40-50% of Americans have had cataract surgery by the age of 75. The only treatment option is a surgical technique to replace the clouded lens inside the eyes with an artificial polymer lens, which is quite frequent and successful in the US.
This study is supported by the National Eye Institute, a division of the National Institutes of Health (2R01EY009532-28A1).