Biophysical investigations of the structure and function of the tear fluid lipid layers and the effect of ectoine. Part B: Artificial lipid films

Abstract

The tear fluid lipid layer is present at the outermost part of the tear film which lines the ocular surface and functions to maintain the corneal surface moist by retarding evaporation. Instability in the structure of the tear fluid lipid layer can cause an increased rate of evaporation and thus dry eye syndrome. Ectoine has been previously shown to fluidize lipid monolayers and alter the phase behavior. In the current study we have investigated the effect of ectoine on the artificial tear fluid lipid layer composed of binary and ternary lipid mixtures of dipalmitoyl phosphatidylcholine (DPPC), cholesteryl esters and tri-acyl-glycerols. The focus of our study was mainly the structural and the biophysical aspects of the artificial tear fluid lipid layer using surface activity studies and topology analysis. The presence of ectoine consistently causes an expansion of the pressure-area isotherm indicating increased intermolecular spacing. The topology studies showed the formation of droplet-like structures due to the addition of ectoine only when tri-acyl-glycerol is present in the mixture of DPPC and chol-palmitate, similar to the natural meibomian lipids. Consequently, the hypothesis of an exclusion of tri/di-acyl-glycerol from the meibomian lipid film in the presence of ectoine in the subphase is confirmed. A model describing the effect of ectoine on meibomian lipid films is further presented which may have an application for the use of ectoines in eye drops as a treatment for the dry eye syndrome.

Biosynthesis And The Possibility Of Using Ectoine And Hydroxyectoine In Health Care

“…It has also been demonstrated that ectoine can protect entire cells (Table IV). It increases the fluidity of cell membranes under extreme conditions [40] and increases the distance between lipid molecules, which improves membrane fluidity [28]. Other researchers report that ectoine may affect the synthesis of chape-rone proteins such as heat shock proteins (Hsp), and it is also assumed that the ectoine itself may act as a chaperone molecule [7,19].…”

Effectiveness, Tolerability, and Safety of Ectoine-Containing Mouthwash Versus Those of a Calcium Phosphate Mouthwash for the Treatment of Chemotherapy-Induced Oral Mucositis: A Prospective, Active-Controlled, Non-interventional Study

“…It has also been shown to rescue cells from apoptosis [ 16 , 17 ]. Furthermore, ectoine can stabilize biological membranes and rehydrate dry, irritated mucosa [ 18 – 20 ], which is essential for the body’s defense against oral infections. These membrane-stabilizing and inflammation-reducing effects of ectoine-containing products have been demonstrated in several clinical studies [ 21 – 23 ].…”

Efficacy and tolerability of an ectoine mouth and throat spray compared with those of saline lozenges in the treatment of acute pharyngitis and/or laryngitis: a prospective, controlled, observational clinical trial

“…Recently, the inflammation-reducing properties of ectoine have been demonstrated in several preclinical [ 7 – 9 ] and clinical studies involving different indications [ 10 – 13 ]. Ectoine increases both the stability and fluidity of biomembrane layers as demonstrated in biophysical experiments [ 14 – 16 ], leading to the increased stabilization of the epithelial barrier, the subsequent reduction in inflammation, and protection against stress [ 17 ]. The stabilization effect on the barrier function of the epithelia tissue has led to the hypothesis that ectoine increases the resistance of the pharyngeal mucosa and improves its recovery.…”