Circulating eNAMPT in Glaucoma: A Semi-Quantitative Plasma Analysis Before and After Nicotinamide Supplementation.

Area of Science:

• Ophthalmology
• Neuroscience
• Biochemistry

Background:

• Glaucoma involves progressive retinal ganglion cell degeneration.
• Nicotinamide supplementation may offer neuroprotection by boosting NAD levels via the NAMPT salvage pathway.
• Extracellular NAMPT (eNAMPT) in blood may reflect NAD biosynthetic capacity and susceptibility to glaucoma.

Purpose of the Study:

• Develop a specific assay for plasma eNAMPT detection.
• Investigate plasma eNAMPT as a potential biomarker for glaucoma.
• Assess the impact of nicotinamide supplementation on circulating eNAMPT levels.

Main Methods:

• Developed a semiquantitative Western blotting assay for plasma eNAMPT.
• Utilized samples from a prospective clinical trial (30 controls, 90 glaucoma patients).
• Assessed intra- and inter-assay variability for the eNAMPT assay.

Main Results:

• Successfully detected plasma eNAMPT (52 kDa) and transferrin (77 kDa) using Western blotting.
• Intra-assay variability was 14.9%, and inter-assay variability was 37.9%.
• No significant differences in eNAMPT levels were observed between glaucoma patients and controls, or after nicotinamide supplementation.

Conclusions:

• Established a reliable method for detecting plasma eNAMPT in glaucoma and control subjects.
• The study provides a foundation for developing eNAMPT as a liquid biopsy biomarker.
• Further research is required to elucidate eNAMPT's role in glaucoma and response to nicotinamide therapy.