High ambient temperature may induce presbyopia via TRPV1 activation

Area of Science:

• Ophthalmology
• Molecular Biology
• Environmental Health

Background:

• Presbyopia and nuclear cataracts (NUC) are more prevalent in tropical regions.
• High ambient temperatures are suspected to influence lens health.
• Transient receptor potential vanilloid (TRPV) channels, including TRPV1 and TRPV4, are present in human lens epithelial cells and detect temperature.

Purpose of the Study:

• To investigate the effect of ambient temperatures on TRPV1 and TRPV4 activity in the lens.
• To explore the potential role of temperature-induced TRPV channel activity in the development of presbyopia and NUC.

Main Methods:

• Cultured human lens epithelial cell lines were exposed to different temperature conditions (35.0°C vs. 37.5°C).
• Activation of downstream signaling pathways (MEK/ERK, p38, Src family kinase) was analyzed.
• TRPV1 expression was visualized using confocal microscopy.
• Lens elasticity was measured in organ culture at varying temperatures.

Main Results:

• At 37.5°C compared to 35.0°C, TRPV1 downstream pathways (MEK/ERK, p38) were activated, and TRPV4 downstream Src family kinase was inhibited.
• Higher TRPV1 expression was observed in 3D cell cultures under high-temperature conditions.
• Elevated temperatures led to increased lens elasticity in organ cultures.

Conclusions:

• High ambient temperatures may induce lens sclerosis through TRPV1 activation.
• This temperature-induced mechanism could contribute to the higher prevalence of presbyopia and NUC in tropical areas.
• TRPV channels represent potential therapeutic targets for mitigating heat-related lens damage.