Surface Pressure Measurements of Human Tears and Individual Tear Film Components Indicate That Proteins Are Major Contributors to the Surface Pressure

Tragoulias, Sophia T; Anderton, Philip J.; Dennis, Gary R.; Miano, Fausto; Millar, Thomas J.

doi:10.1097/01.ico.0000138837.52694.37

Cited by 61 publications

(60 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1. The isotherms of the three "pure" compounds, MGS, SM and DPPC coincide well with the previously published results obtained under similar conditions [18][19][20]29,34]. MGS isotherm shows low slope (i.e.…”

Section: Quasi-equilibrium Compression Of Mixed Films Of Mgs and Plssupporting

confidence: 90%

“…MGS isotherm shows low slope (i.e. high compressibility) with characteristic inflexion at 15-17 mN and maximal surface pressure of 25 mN/m as reported in [18][19][20].…”

Section: Quasi-equilibrium Compression Of Mixed Films Of Mgs and Plsmentioning

confidence: 57%

“…For the purpose we formed mixed pseudo-binary films of MGS and polar lipid, Egg Sphingomyelin (SM) or Dipalmitoylphosphatidylcholine (DPPC), at the air/water interface of Langmuir surface balance. Langmuir surface balance was already successfully employed in pioneer studies of the interactions between tear proteins and meibium [18][19][20][21][22][23]. SM and DPPC are chosen because they were used in previous studies as synthetic mimics of TF polar lipids [24,25].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

Georgiev

Kutsarova

Jordanova

et al. 2010

Colloids and Surfaces B: Biointerfaces

View full text Add to dashboard Cite

a b s t r a c tThe surface interactions of Meibomian gland secretion (MGS) with polar lipid (PL), Egg Sphingomyelin (SM) or Dipalmitoylphosphatidylcholine (DPPC), are studied in mixed pseudo-binary films formed at the air/water interface of Langmuir surface balance. The behavior of the mixed films during slow quasi-equilibrium compression and during fast dynamic compression-decompression is registered by measurements of surface pressure and surface potential, and by monitoring film morphology with Brewster Angle Microscopy (BAM). Quasi-equilibrium compression isotherms are used to calculate the excess Gibbs and Helmholtz energy of mixing between MGS and PLs and thus to evaluate the interactions between the lipid compounds at the interface. The effects of PLs on the mixed film's elastic moduli of area compressibility, morphology and capability to attain high surface pressures are also examined.PLs interact with MGS with different strength and in different manner: MGS-SM interaction is weak and might lead to interfacial disaggregation of the thick meibium domains when SM is in excess, while MGS-DPPC interaction is strong and results in the formation of thick lipid aggregates. Both PLs increase the mixed films reciprocal compressibility and capability to achieve higher surface pressures. The results demonstrate that in vitro studies of the surface interactions between MGS and PLs might be beneficial in the selection of PLs for artificial tear formulations and for examination on molecular scale of the possible role of PLs at the ocular surface.

show abstract

Section: Quasi-equilibrium Compression Of Mixed Films Of Mgs and Plssupporting

confidence: 90%

“…MGS isotherm shows low slope (i.e. high compressibility) with characteristic inflexion at 15-17 mN and maximal surface pressure of 25 mN/m as reported in [18][19][20].…”

Section: Quasi-equilibrium Compression Of Mixed Films Of Mgs and Plsmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

Georgiev

Kutsarova

Jordanova

et al. 2010

Colloids and Surfaces B: Biointerfaces

View full text Add to dashboard Cite

show abstract

“…The present conceptual study clearly illustrates the potential effect of PLs without considering interactions between lipids and proteins. The function of PLs may be highly affected by lipid-binding proteins such as lipocalin, [24][25][26] and PL transfer protein. 27,28 However, more investigations need to be performed regarding the lipid-protein interactions before the impact of the proteins on TFLL behavior can be explained in more detail.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Phospholipids on Tear Film Lipid Layer Surface Activity

Rantamäki

Holopainen

2017

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Citation: Rantamäki AH, Holopainen JM. The effect of phospholipids on tear film lipid layer surface activity. Invest Ophthalmol Vis Sci. 2017;58:149-154. DOI:10.1167/ iovs.16-20468 PURPOSE. We illustrate the importance of small quantities (<10 mol%) of polar phospholipids on the surface-active behavior of meibum-like lipid compositions.METHODS. Artificial meibum-like lipid mixture containing cholesteryl and wax esters was mixed with differing amounts of phosphatidylcholine (PC). The surface activity of these mixtures was investigated at the air-water interface by recording surface pressure created by the lipid layer as a function of molecular area at 378C. The PC proportion in the mixtures was 0, 2.5, 5, 7.5, or 10 mol%, and the remaining proportion in the mixture was 50:50 (mol/mol) of cholesteryl oleate (CO) and behenyl oleate (BO). Also, the effect of temperature was investigated.RESULTS. The surface activity of the mixtures increased in a very predictable and consistent fashion as a function of the PC proportion. The lipid mixture containing only CO and BO showed miniscule surface activity. However, already 2.5% PC mixed with the nonpolar CO and BO generated considerable increase in surface pressure. At small surface areas, the behavior of 7.5% and 10% PC compositions started to approach that of a pure PC monolayer. The temperature did not have a considerable impact on the surface-active behavior of the PCcontaining compositions.CONCLUSIONS. The polar phospholipids have a considerable effect on the surface-active properties of artificial tear film lipid layer (TFLL) compositions. Surprisingly, this takes place already at very low and physiologically relevant PC proportions. The effect is more dependent on the actual amount of the phospholipids at the air-tear interface than on the relative amount of these lipids in TFLL.

show abstract

“…Recently, apart from the bactericidal role, Tragoulias et al (2005) and Millar et al (2006) have suggested that lysozyme contributes to lower the surface tension of the tear fi lm. In this case, an increase in lysozyme levels could contribute to stablizing the tear fi lm, thus avoiding an excessive evaporation and the resulting problems on the ocular surface.…”

Section: Discussionmentioning

confidence: 99%

Topical application of nucleotides increase lysozyme levels in tears

Mosallaei¹

2008

OPTH

View full text Add to dashboard Cite

Abstract:The present work studies the effects of topical application of nucleotides on rabbit tear lysozyme levels. Lysozyme values were determined by the diffusion in Agar method described by van Bijsterveld in 1974, and the protein amount was obtained by measuring the inhibitory halos around a Whatman nº1 paper disc of 5 mm in diameter. The tested nucleotides were UTP, Ap 4 A and Up 4 U. These compounds were topically instilled in a single-dose in one eye (with the contralateral eye as a control) and the lysozyme halos were measured along 5 hours. The obtained results showed an increase in the lysozyme concentrations of 67%, 93%, and 119% for UTP, Ap 4 A, and Up 4 U, respectively, over the basal levels of lysozyme. For this reason, we suggest these molecules as a potential treatment for the reinforcement of the tear fi lm barrier against ocular infection.

show abstract

Surface Pressure Measurements of Human Tears and Individual Tear Film Components Indicate That Proteins Are Major Contributors to the Surface Pressure

Abstract: Comparison between the dynamic Pi-A profiles of tears and those of individual tear film components shows that tear film proteins not only are capable of surface activity but also are major contributors to the surface activity of the tear film.

Cited by 61 publications

References 42 publications

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

The Effect of Phospholipids on Tear Film Lipid Layer Surface Activity

Topical application of nucleotides increase lysozyme levels in tears

Contact Info

Product

Resources

About