This review re-examines the bioenergetics of retinal rod outer segments (ROS), integrating historical biochemical data, proteomics, and functional evidence to evaluate how the mitochondria-free outer segment meets its rapid ATP demands during phototransduction.
The authors propose a 'triple metabolic hypothesis': inner segment mitochondria, aerobic glycolysis, and a putative ectopic oxidative phosphorylation system within outer segment disks work in concert to supply localized and divergent ATP demands across the light/dark cycle. Disruption of this compartmentalized system is linked to redox imbalance and photoreceptor vulnerability in aging and acquired retinal dystrophies.
Full text was inaccessible; summary is based on the abstract alone. The ectopic oxidative phosphorylation system in the outer segment disks is described as 'putative,' meaning direct experimental confirmation in vivo remains lacking. No clinical trial data or patient cohorts are included—this is a mechanistic review.
Clinicians treating acquired retinal dystrophies (e.g., age-related macular degeneration) should be aware that outer segment metabolic failure—not just RPE dysfunction—may drive photoreceptor loss, potentially informing future therapeutic targets aimed at supporting local rod bioenergetics.
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