Alginate- and Hyaluronic Acid–Based Hydrogels as Vitreous Substitutes: An In Vitro Evaluation

Schulz, André; Rickmann, Annekatrin; Wahl, Silke; Germann, Anja; Stanzel, Boris V.; Januschowski, Kai; Szurman, Peter

doi:10.1167/tvst.9.13.34

Cited by 30 publications

(32 citation statements)

References 36 publications

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“…Moreover, the current outcomes suggest that the introduction of new tamponades contacting the entire retina would be highly desirable. 24 A 360° scleral band does not increase SiO contact, although it may contrast retinal shortening and traction vectors, and it certainly promotes a significant shear stress increase at the indentation site. The pitfalls of the present study are primarily related to the uncertainties of SiO–retina static and dynamic interactions, as well as the deviation of normal human anatomy from the standardized vitreous chamber shape adopted here.…”

Section: Discussionmentioning

confidence: 96%

Silicone Oil Tamponade–Retina Contact in Highly Myopic Eyes With and Without Encircling Bands: A Computational Fluid Dynamics Study

Rossi

Querzoli

Badas

et al. 2022

Trans. Vis. Sci. Tech.

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Purpose To investigate the behavior of silicone oil (SiO) at a steady equilibrium and during saccades in pseudophakic highly myopic eyes with posterior staphyloma with and without an encircling band and compare it to behavior in emmetropic eyes. The SiO–retina contact area and shear stress were calculated by computational fluid dynamics. Methods A numerical model of an emmetropic eye and a myopic eye with and without scleral band underwent a saccade of 50°/0.137 s. The vitreous chamber surface was divided into superior and inferior 180° sectors: lens, pre-equator, post-equator, and macula. SiO–retina contact was evaluated as a function of fill percentages between 80% and 90% for standing, 45° upward tilt, and supine patients. Maximum and average shear stress were calculated. Results Overall, SiO–retina contact ranged between 40% and 83%; fill percentage varied between 80% and 95%. Neither the encircling scleral band nor the staphyloma significantly affected the SiO–retina contact area, although the presence of a scleral band proved disadvantageous when gazing 45° upward. The inferior retina–SiO contact remained below 40% despite 95% SiO fill. The SS significantly increased at the scleral band indentation and decreased elsewhere. The staphyloma greatly reduced shear stress at the macula. Conclusions The presence of a myopic staphyloma reduces shear stress at the macula but does not alter SiO–retina contact significantly. The apposition of a 360° scleral band may reduce SiO–retina contact at least in some postures and increases the SS at the indentation. Translational Relevance Assessing SiO–retina contact when vitreous chamber geometry changes according to pathologic or iatrogenic modifications allows accurate prediction of real-life tamponade behavior and helps explain surgical outcomes.

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Section: Discussionmentioning

confidence: 96%

Silicone Oil Tamponade–Retina Contact in Highly Myopic Eyes With and Without Encircling Bands: A Computational Fluid Dynamics Study

Rossi

Querzoli

Badas

et al. 2022

Trans. Vis. Sci. Tech.

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“…Therapies for complicated retinal detachments often includes the removal of the VH (vitrectomy), and its replacement with an endotamponade such as perfluorocarbons, air, gases and silicone oils and hydrophilic, hydrogel-based systems such as hyaluronic acid, has been reviewed [ 51 ]. The strategy behind the tamponade is to stabilize the retina.…”

Section: Discussionmentioning

confidence: 99%

“…The strategy behind the tamponade is to stabilize the retina. HA tamponades such as HA offer the advantage over hydrophobic tamponades in that they do not leave a small amount of liquid at the opposite pole of the buoyancy vector wherein growth factors accumulate and promote pro-inflammatory processes [ 51 ]. Hydrophobic tamponades also lead to complications such as emulsification, cataract formation, and the need for revision surgery.…”

Section: Discussionmentioning

confidence: 99%

Hyaluronic acid–lipid binding

et al. 2021

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Background Phospholipid (PL)–hyaluronic acid (HA) interactions are relevant to aging-associated vitreous humor liquefaction, therapies for dry eye disease, skin-care products and synovial joint lubrication. Phosphatidyl choline–HA interactions have been well characterized. However, other major lipids found in tears, vitreous humor and synovial joints have not. The purpose of this study was to bridge this gap of knowledge. Methods HA (1600 kDa) at 5 mg/mL, was mixed with various lipids ranging in concentration from 0.1 to 10 mg/mL in D2O. HA–PL binding was measured from the decrease in HA proton resonance intensity with binding using a nuclear magnetic resonance spectrometer. Results Cholesterol weakly bound to HA, followed by monoglyceride and palmitoyl palmitate < phosphatidyl choline, phosphatidic acid and sphingomyelin. The maximum amount of PL bound was 14 ± 1 µmoles inferring a 1 to 1 molar ratio of bound PL to HA dimer. Monoglyceride and palmitoyl palmitate required two to three times more lipid to achieve 100% bound HA compared to PL. Conclusions Physiological levels of HA, phosphatidyl choline and sphingomyelin would result in only 4% of the hydrophobic hydrogens of HA to be bound. HA–PL binding interactions could be important for therapeutic use of HA in eye drops in future studies to treat dry eye and to trap PL entering the VH to keep them from forming light scattering micelles. HA–lipid binding may also be relevant to the therapeutic effects of topical skin-care products. Both head group and hydrocarbon chain moieties influence HA–lipid interactions.

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“…Facsimiles were synthesized using hydrogel beads of alginate, a natural polysaccharide commonly used in biomaterial applications of drug release and ophthalmology [ 46 , 47 , 48 ]. Facsimiles were produced with an approximate diameter of 3 mm to model the adult murine eye and were synthesized by mixing solutions of sodium alginate (Cat.…”

Section: Methodsmentioning

confidence: 99%

A Microfluidic Eye Facsimile System to Examine the Migration of Stem-like Cells

2022

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Millions of adults are affected by progressive vision loss worldwide. The rising incidence of retinal diseases can be attributed to damage or degeneration of neurons that convert light into electrical signals for vision. Contemporary cell replacement therapies have transplanted stem and progenitor-like cells (SCs) into adult retinal tissue to replace damaged neurons and restore the visual neural network. However, the inability of SCs to migrate to targeted areas remains a fundamental challenge. Current bioengineering projects aim to integrate microfluidic technologies with organotypic cultures to examine SC behaviors within biomimetic environments. The application of neural phantoms, or eye facsimiles, in such systems will greatly aid the study of SC migratory behaviors in 3D. This project developed a bioengineering system, called the μ-Eye, to stimulate and examine the migration of retinal SCs within eye facsimiles using external chemical and electrical stimuli. Results illustrate that the imposed fields stimulated large, directional SC migration into eye facsimiles, and that electro-chemotactic stimuli produced significantly larger increases in cell migration than the individual stimuli combined. These findings highlight the significance of microfluidic systems in the development of approaches that apply external fields for neural repair and promote migration-targeted strategies for retinal cell replacement therapy.

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Alginate- and Hyaluronic Acid–Based Hydrogels as Vitreous Substitutes: An In Vitro Evaluation

Cited by 30 publications

References 36 publications

Silicone Oil Tamponade–Retina Contact in Highly Myopic Eyes With and Without Encircling Bands: A Computational Fluid Dynamics Study

Silicone Oil Tamponade–Retina Contact in Highly Myopic Eyes With and Without Encircling Bands: A Computational Fluid Dynamics Study

Hyaluronic acid–lipid binding

A Microfluidic Eye Facsimile System to Examine the Migration of Stem-like Cells

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