Time-dependent degenerative transformations in the lipidome of chalazia

Abstract

The aim of this prospective study was to conduct histopathologic and lipidomic analyses of chalazia, in order to evaluate time-dependent changes in the lesion. Samples of surgically excised chalazia were collected over a period of 12 months from 10 patients (mean age 41 years; range, 23–58) with clinically diagnosed chalazia, who underwent scheduled surgery. The ages of chalazia varied from 2 to 28 weeks. To confirm the clinical diagnoses, the morphology of collected tissue samples was evaluated histologically after hematoxylin and eosin staining. The lipids from individual chalazia were analyzed by high-performance liquid chromatography-mass spectrometry and compared with authentic lipid standards and with the lipids of meibum collected from normal controls. We observed gradual, lesion age-dependent transformation of the lipidome of chalazia from an almost normal meibum-like composition to a very different kind of lipidome. A rapid initial increase in the free cholesterol content was followed by a gradual replacement of extremely long chain meibomian-type lipids with a mixture of shorter-chain cholesteryl esters of the C14-C18 family, triacylglycerols, ceramides, phospholipids and sphingomyelins. In addition, a rapid disappearance of wax esters and cholesteryl esters of (1-O)-acyl-omega-hydroxy fatty acids from the lipidome of aging chalazia was observed. Our results are indicative of dramatic, time-dependent changes in the lesion that may involve cholesterol as a trigger and/or a marker of subsequent degeneration of the meibomian lipidome. We hypothesize that early inhibition of these transformations may be useful in reversing the course of the disease.

Dissecting lipid metabolism in meibomian glands of humans and mice: An integrative study reveals a network of metabolic reactions not duplicated in other tissues

“…Human meibum had been extensively characterized in our previous publications in detail [16, 22–25, 30–39, and references therein] and was used in this study only to compare it with meibum of mice. Notably, inter-donor variability in the molar ratios of major tested lipids (WE and CE) in meibum of normal, non-DE humans was found to be rather low [36, 38, 39] and not exceeding ±15%.…”

“…TF/TFLL combination also serves as a lubricant [11] that smoothes movements of the eyeball and the eyelids, and improves visual acuity [12, 13]. In humans, diseases such as various forms of Dry Eye (DE) [14] and chalazion – an ocular lesion that typically originates from MG [15, 16] – have been linked to dysfunctionalities in MG, which result either in abnormal lipid secretions, or insufficient production or expression of meibum [17]. DE disease affects a large portion of the human population (between 8 and 30%, depending on the region and diagnostic criteria) [18, 19].…”

Effects of chalazion and its treatments on the meibomian glands: non-randomized, prospective observation clinical study

“…Previous studies showed that chalazia were mainly composed of macrophages, neutrophils and epithelial cells. 16,17 Moreover,…”

“…The lipid component of chalazion was different from normal meibomian gland lipids. 17 However, infrared meibomian gland photography is based on the theory that the lipid particles in the meibomian gland are excited by infrared rays and emit scattered light. 18 A chalazion is composed of granulomatous substances and abnormal lipids before treatment.…”

“…Previous study found that the ratio of cholesterol/cholesterol esters (Chl/CE) was increased in the abnormal lipid component of the chalazion and suggested that an increase in Chl levels might send a chemotactic signal to the inflammatory cells to invade the meibomian gland. 17 The inflammatory cells could cause a physical blockage of the meibomian gland or meibum thickening, which would obstruct the expression of meibum. As a result, this abnormal lipid material might invade the surrounding tissues and intensify the inflammatory response in the meibomian glands.…”