Multi-omics liquid biopsy identifies mitochondrial dysfunction in geographic atrophy and supports the longevity-associated metabolite α-ketoglutarate as a therapeutic strategy

Tsai-Chu Yeh; Gabriel Velez; Architesh Prasad; Soo Hyeon Lee; Ditte K Rasmussen; Aarushi Kumar; Madhumeeta Chadha; Mohamed Ziad Dabaja; Aneal M Singh; Steven Sanislo; Stephen Smith; Prithvi Mryuthyunjaya; Artis Montague; Alexander G Bassuk; David Almeida; Antoine Dufour; Vinit B Mahajan

doi:10.64898/2026.03.12.26347263

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 ocular liquid biopsy enables real-time proteomic and metabolomic profiling of the intraocular microenvironment, complementing systemic biomarkers and imaging surrogates. Here, 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.BackgroundMitochondrial 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 ocular liquid biopsy enables real-time proteomic and metabolomic profiling of the intraocular microenvironment, complementing systemic biomarkers and imaging surrogates. Here, 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.MethodsMitochondrial 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.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 consistent with enhanced TCA cycle flux.ResultsIn 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 consistent with enhanced TCA cycle flux.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.ConclusionsAH 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 (GA) is an advanced form of age-related macular degeneration and a major cause of irreversible vision loss. To better understand the biology of GA, we studied proteins and small molecules in aqueous humor, the fluid inside the eye. We found that eyes with GA showed clear signs of mitochondrial dysfunction, including disruptions in the tricarboxylic acid (TCA) cycle, a key pathway for energy production. This suggests that impaired cellular metabolism is an important feature of the disease. We then tested whether oral α-ketoglutarate (α-KG), a metabolite involved in mitochondrial function and previously shown to have life-extending effects in preclinical studies, could alter these metabolic pathways in the human eye. We found that α-KG supplementation not only increased intraocular α-KG levels but changed metabolic markers linked to mitochondrial activity, providing the first direct evidence that oral supplementation can reach the eye and measurably modify metabolism inside the living human eye. Together, these findings show that liquid biopsy can provide a direct molecular snapshot of the living human eye and may help accelerate the development of biomarker-guided therapies for ocular diseases.Plain Language SummaryGeographic atrophy (GA) is an advanced form of age-related macular degeneration and a major cause of irreversible vision loss. To better understand the biology of GA, we studied proteins and small molecules in aqueous humor, the fluid inside the eye. We found that eyes with GA showed clear signs of mitochondrial dysfunction, including disruptions in the tricarboxylic acid (TCA) cycle, a key pathway for energy production. This suggests that impaired cellular metabolism is an important feature of the disease. We then tested whether oral α-ketoglutarate (α-KG), a metabolite involved in mitochondrial function and previously shown to have life-extending effects in preclinical studies, could alter these metabolic pathways in the human eye. We found that α-KG supplementation not only increased intraocular α-KG levels but changed metabolic markers linked to mitochondrial activity, providing the first direct evidence that oral supplementation can reach the eye and measurably modify metabolism inside the living human eye. Together, these findings show that liquid biopsy can provide a direct molecular snapshot of the living human eye and may help accelerate the development of biomarker-guided therapies for ocular diseases.Questions: What specific mitochondrial and TCA-cycle dysfunctions occur in the aqueous humor (AH) of patients with geographic atrophy (GA), and can oral α-ketoglutarate (α-KG) supplementation measurably remodel these metabolic pathways in the living human eye?Findings: AH proteomics in GA patients revealed significant mitochondrial disruption and a coordinated depletion of TCA-cycle enzymes. In a paired-eye interventional metabolomics study, oral α-KG significantly increased intraocular α-KG levels and the α-KG-to-succinate ratio, proving that systemic therapy can drive measurable metabolic modulation within the human eye.Meaning: Multi-omics liquid biopsy provides a direct, eye-specific readout of mitochondrial metabolism in GA and offers early human proof-of-concept that a systemic metabolic therapy can successfully reach and modify intraocular pathways, paving the way for biomarker-guided clinical trials in AMD.Key PointsQuestions: What specific mitochondrial and TCA-cycle dysfunctions occur in the aqueous humor (AH) of patients with geographic atrophy (GA), and can oral α-ketoglutarate (α-KG) supplementation measurably remodel these metabolic pathways in the living human eye?Findings: AH proteomics in GA patients revealed significant mitochondrial disruption and a coordinated depletion of TCA-cycle enzymes. In a paired-eye interventional metabolomics study, oral α-KG significantly increased intraocular α-KG levels and the α-KG-to-succinate ratio, proving that systemic therapy can drive measurable metabolic modulation within the human eye.Meaning: Multi-omics liquid biopsy provides a direct, eye-specific readout of mitochondrial metabolism in GA and offers early human proof-of-concept that a systemic metabolic therapy can successfully reach and modify intraocular pathways, paving the way for biomarker-guided clinical trials in AMD.

Multi-omics liquid biopsy identifies mitochondrial dysfunction in geographic atrophy and supports the longevity-associated metabolite α-ketoglutarate as a therapeutic strategy

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