Multi-omics liquid biopsy identifies mitochondrial dysfunction in geographic atrophy and supports intraocular bioavailability of α-ketoglutarate

Mitochondrial dysfunction is an emerging metabolic hallmark of age-related diseases, yet tools to directly profile mitochondrial pathways and test metabolic interventions in the living human eye remain limited. Multi-omics liquid biopsy enables real-time proteomic and metabolomic profiling of the intraocular microenvironment, complementing systemic biomarkers and imaging surrogates. We used this approach to define mitochondrial and tricarboxylic acid (TCA) cycle dysregulation in geographic atrophy (GA) and to assess whether oral α-ketoglutarate (α-KG) supplementation can modulate mitochondrial metabolites within the eye. Mitochondrial and TCA cycle-related proteins were profiled in aqueous humor (AH) samples from patients with GA using DNA-aptamer-based proteomics. In a phase 0 study, a second cohort undergoing sequential cataract surgery provided paired AH samples collected at first-eye surgery and at second-eye surgery after interim α-KG supplementation. These samples underwent targeted metabolomic profiling using hydrophilic interaction liquid chromatography coupled with mass spectrometry. This study was registered at ClinicalTrials.gov (NCT07269704). In GA, 64 mitochondrial proteins were differentially expressed, including coordinated TCA-cycle deficiencies marked by reduced expression of enzymes regulating TCA entry and flux, including PDHB and DLST. In the phase 0 cohort, oral α-KG supplementation significantly increased intraocular α-KG levels and the α-KG-to-succinate ratio (P < 0.05), with coordinated shifts across TCA intermediates indicating intraocular target engagement by orally supplemented α-KG. AH proteomics demonstrated mitochondrial pathway depletion in GA, consistent with reduced oxidative bioenergetic capacity. AH metabolomics provided first-in-human in vivo evidence that systemic α-KG supplementation can modify intraocular metabolites and may enhance intraocular energy metabolism. These findings support ocular liquid biopsy as a precision-health framework for per-patient biomarker-guided metabolic trials in GA. Geographic atrophy is a common eye disease in older people that slowly damages the retina and causes permanent sight loss. The causes of this disease are not fully understood. To investigate this, we tested small samples of fluid taken from inside the eye during routine surgery. Eyes with geographic atrophy showed clear signs that energy production was affected. We gave a natural nutrient, called alpha-ketoglutarate, to a separate group of patients having cataract surgery. Taken by mouth for one week, it reached the eye and changed energy-related chemicals there. This shows that a pill can alter eye metabolism, which may lead to new treatments. The authors sample fluid from inside the living human eye to profile mitochondrial proteins in geographic atrophy and to test whether an oral supplement reaches the eye. They find widespread mitochondrial protein loss in disease and show that oral alpha-ketoglutarate enters the eye and shifts its energy metabolism.