Quantitative Analysis of Arachidonic Acids

Arachidonic acid is an 2-carbon unsaturated fatty acid. Under the action of inflammatory stimuli and mediators, it is metabolized by cyclooxygenase and lipid oxygenase pathways to generate various metabolites, mainly has prostaglandins (PG) and Leukotriene (LT). Inflammation stimulates arachidonic acid and releases its metabolites, led to inflammatory reactions such as fever, pain, vasodilation, increased permeability, and leukocyte exudation.

Application Fields

Research on the mechanism of disease

Disease marker

Evaluation of drugs

Sample Requirements

Solid 2g
Cells ≥ 5×10⁶
Liquid 500μl
Recommended to repeat more than 6 times
Sample type: animal and plant, tissue, blood, etc.

Liquid/solid samples, dry ice shipping; large pieces need to be cut into 1cm pieces

Case Analysis

Change of Tear Lipid Mediators in a Post-trabeculectomy Cohort

Journal: Ocular Surface Impact factor: 12.33 Published date: July, 2020 Published by: National University of Singapore

Research Background

Trabeculectomy surgery could affect ocular surface disease (OSD) in several ways, through cessation of long term glaucoma eyedrops, exposure to operative mitomycin C and post-operative eyedrops including corticosteroids and aminoglycosides and reduction in eyelid hygiene measures. Previously we showed the relevance of tear lipid mediators (also referred oxylipins) in OSD. Here, we aim to evaluate changes of these lipids in a post-trabeculectomy cohort.

Research Method

Patients undergoing trabeculectomy were prospectively evaluated and had tear collected using Schirmer’s strips, preoperatively and postoperatively at 0.5, 1.0 and 3.0 years. Lipid mediators were analyzed using liquid chromatography mass spectrometry.

Research Result

The normalized concentrations of 40 lipid mediators were between 0.1-8.0 ng/mL, whereas docosahexaenoic acid (DHA), Arachidonic acid (AA) and eicosapentaenoic acid (EPA) ranged up to a few hundred ng/mL. The concentrations of lipid mediators, except DHA, EPA, and thromboxane (TXB1), showed reduction after surgery.

Figure 1 Complete and representative chromatograms of LC-MS/MS extracted tear samples and standards

Figure 2 Heat map of postoperative lipid mediator trends over time

Figure 3 Unsupervised hierarchical clustering heat maps

Figure 4 Effects of trabeculectomy on lipid medium levels from baseline to last recorded values

Conclusion

In this 3-years study, trabeculectomy reduced the tear level of proinflammatory lipid mediators.

Reference

Ambaw Yohannes Abere,Wong Tina,Chong Rachel et al. Change of tear lipid mediators in a post-trabeculectomy cohort.[J] .Ocul Surf, 2020