Sphingolipids and ceramides in human aqueous humor

Area of Science:

• Biochemistry
• Ophthalmology
• Lipidomics

Background:

• Sphingolipids, including sphingomyelin, sphingoid bases, sphingoid base-1-phosphates, and ceramides, play crucial roles in cellular function.
• Alterations in lipid profiles are implicated in various pathological conditions, including glaucoma.

Purpose of the Study:

• To investigate the differential profiles and quantitative differences of sphingomyelin, sphingoid base, sphingoid base-1-phosphate, and ceramide lipid species in human aqueous humor.
• To compare these lipid profiles between control and primary open-angle glaucoma donors.

Main Methods:

• Aqueous humor (AQH) was collected from control and glaucoma donors.
• Lipid extraction and quantification were performed using modified Bligh and Dyer method and mass spectrometry (precursor ion scan/neutral loss scan).
• Primary human trabecular meshwork cells were exposed to a specific ceramide to assess cellular changes.

Main Results:

• Common sphingolipid and ceramide species were identified in both control and glaucomatous AQH.
• Unique lipid species were found in control AQH but absent in glaucoma, and vice versa.
• Exposure to a specific ceramide induced changes in trabecular meshwork cell shape and motility.

Conclusions:

• While most sphingolipids and ceramides were shared between control and glaucoma groups, specific unique species were identified.
• The presence or absence of unique lipid species in the pathophysiological context of glaucoma may provide new insights into disease mechanisms.
• Ceramide-induced cellular changes highlight potential roles in glaucoma pathology.