Laser heat activates AMD defences
A temperature-controlled near-infrared laser treatment may help retinal cells activate natural repair and clean-up pathways before dry age-related macular degeneration (AMD) advances, said researchers in Finland.
Researchers in the Aalto University preclinical study used focal electroretinography-based thermal dosimetry to monitor retinal temperature in real time during laser exposure in anaesthetised male pigs. They found that raising retinal temperature to 44°C for 60 seconds triggered heat-shock protein production and autophagy activation in the retinal pigment epithelium/choroid without oxidative stress, apoptosis or structural damage.
Published in Nature Communications, the study’s method was designed to address variable patient responses to laser-induced retinal pigment epithelium hyperthermia, which has been difficult to dose because of differences in pigmentation and heat absorption. Visible lesions occurred above 48°C, while temperature determination precision at the lesion threshold was 0.6°C, the researchers found.
Professor Ari Koskelainen said the approach aimed to strengthen affected cells’ protective mechanisms and establish whether the non-damaging, temperature-controlled approach can be used as a repeatable outpatient therapy for early retinal disease. The treatment has also been tested in mice, with first in-human safety studies the next step.
