scholarly journals Why Chain Length of Hyaluronan in Eye Drops Matters

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 511 ◽  
Author(s):  
Wolfgang G.K. Müller-Lierheim
Keyword(s):  
Molecular Weight ◽  
Epithelial Cells ◽  
Chain Length ◽  
Ocular Surface ◽  
Clinical Performance ◽  
Average Molecular Weight ◽  
Tear Film ◽  
Eye Drops ◽  
Zero Shear Viscosity ◽  
Corneal Epithelial

The chain length of hyaluronan (HA) determines its physical as well as its physiological properties. Results of clinical research on HA eye drops are not comparable without this parameter. In this article methods for the assessment of the average molecular weight of HA in eye drops and a terminology for molecular weight ranges are proposed. The classification of HA eye drops according to their zero shear viscosity and viscosity at 1000 s−1 shear rate is presented. Based on the gradient of mucin MUC5AC concentration within the mucoaqueous layer of the tear film a hypothesis on the consequences of this gradient on the rheological properties of the tear film is provided. The mucoadhesive properties of HA and their dependence on chain length are explained. The ability of HA to bind to receptors on the ocular epithelial cells, and in particular the potential consequences of the interaction between HA and the receptor HARE, responsible for HA endocytosis by corneal epithelial cells is discussed. The physiological function of HA in the framework of ocular surface homeostasis and wound healing are outlined, and the influence of the chain length of HA on the clinical performance of HA eye drops is illustrated. The use of very high molecular weight HA (hylan A) eye drops as drug vehicle for the next generation of ophthalmic drugs with minimized side effects is proposed and its advantages elucidated. Consequences of the diagnosis and treatment of ocular surface disease are discussed.

Comparison of Ocular Surface Cytological Appearance in Glaucoma Patient Treated with Timolol Maleat 0,5% Latanoprost 0,005% and Timolol-Latanoprost Fixed Combination Preservative Free Eye Drop

2019 ◽  
Vol 44 (2) ◽  
pp. 82
Author(s):  
Maretha Amrayni ◽  
Elsa Gustianty ◽  
Susi Heryati ◽  
Andika Prahasta ◽  
Maula Rifada ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Density ◽  
Goblet Cell ◽  
Ocular Surface ◽  
Fixed Combination ◽  
Cell Contact ◽  
Corneal Epithelial ◽  
Preservative Free ◽  
Goblet Cell Density ◽  
Epithelial Metaplasia

Introduction : The longterm use of topical antiglaucoma might cause ocular surface instability due to active substance or preservative used. Impression cytology examination may reveal superficial epithelial cells on conjunctiva and cornea, including goblet cells. Goblet cell density decrease is the most important parameter on evaluation of ocular surface disorder. Objective : This study was to understand ocular surface remodeling due to active substance of topical antiglaucoma with impression cytology examination among the patient prior and 3 months after therapy. Methods : This was a randomized controlled trial study with single blind masking. A total of 45 eyes from 31 patients were used as subject and distributed onto three groups treatment, which were timolol maleat 0.5%, latanoprost 0.005%, and latanoprost-timolol maleat fixed combination. All topical antiglaucoma in this study were preservative free. Result : There were differences between 3 groups in goblet cells density after 3 months therapy (p=0,030). Goblet cell density in timolol group was lower than latanoprost (p=0,041) and fixed combination (p=0,045). There was no significantly difference between 3 groups in conjunctival epithelial metaplasia degree (p=0,706) and cell to cell contact degree in corneal epithelial cells (p=0.66) after 3 months therapy. Conjunctival epithelial metaplasia degree were increased among group of timolol (p=0,008) and fixed combination (p=0,046). Conclusion : Timolol maleat 0,5% caused lower goblet cell density after 3 months therapy compare with latanoprost and fixed combination. There was no significantly difference in conjunctival epithelial metaplasia and cell to cell contact degree in corneal epithelial cells among these glaucoma treatment groups.

scholarly journals Human Serum Eye Drops in Eye Alterations: An Insight and a Critical Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Maria Rosaria De Pascale ◽  
Michele Lanza ◽  
Linda Sommese ◽  
Claudio Napoli
Keyword(s):  
Human Serum ◽  
Clinical Studies ◽  
Tear Film ◽  
Eye Drops ◽  
Corneal Epithelial ◽  
Activated Platelets ◽  
Open Debate ◽  
Potential Benefits ◽  
Serum Eye Drops

Human serum contains a physiological plethora of bioactive elements naturally released by activated platelets which might have a significant effect on the regeneration of corneal layers by stimulating the cell growth. This mechanism supported the use of human serum eye drops in some ocular diseases associated with dystrophic changes and alterations of the tear film, such as persistent corneal epithelial defects and dry eye syndrome. We focused our effort on potential benefits and limitations of the use of human serum eye drops when conventional therapies failed. We reviewed the recent literature by reporting published studies from 2010 to 2014. Despite the limited evaluated study populations, most of the clinical studies have confirmed that serum eye drop therapy is effective in corneal healing by reducing ocular symptom, particularly during the short-term follow-up. In addition, three recent published studies have shown the efficacy of the serum eye drop therapy in comparison to traditional ones in intractable patients. Besides, reported ongoing clinical studies confirmed the open debate regarding the use of biologic tools for cornea regeneration. Results from these studies might open novel challenges and perspectives in the therapy of such refractory patients.

scholarly journals Autologous Blood Products: When, Where, and How?

2021 ◽  
Vol 8 (1) ◽  
pp. 1-9
Author(s):  
Alfonso L Sabater ◽  
Keyword(s):  
Ocular Surface ◽  
Keratoconjunctivitis Sicca ◽  
Therapeutic Option ◽  
Autologous Blood ◽  
Stevens Johnson Syndrome ◽  
Eye Drops ◽  
Corneal Epithelial ◽  
Johnson Syndrome ◽  
Ocular Surface Diseases ◽  
Persistent Epithelial Defects

Autologous blood eye drops have become an interesting, well-known, and widely used therapeutic option for many ocular surface diseases since their introduction into the ophthalmologic field forty-six years ago. The foundation for their use in the treatment of pathologies such as severe keratoconjunctivitis sicca, persistent epithelial defects, ocular chemical burns, recurrent epithelial erosions, Stevens-Johnson syndrome, ocular graft versus host disease, and, lately, in many other ocular surface conditions, relies on the fact that they contain proteins, vitamins, cytokines, and growth factors that participate in the signaling pathways of corneal epithelial healing in similar amounts to those found in normal, healthy tear films

Engineering of Stable Recombinant Bacteria for Production of Chiral Medium-Chain-Length Poly-3-Hydroxyalkanoates

1999 ◽  
Vol 65 (8) ◽  
pp. 3265-3271 ◽  
Author(s):  
Maria A. Prieto ◽  
Michele B. Kellerhals ◽  
Gian B. Bozzato ◽  
Dragan Radnovic ◽  
Bernard Witholt ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Chain Length ◽  
Expression System ◽  
Average Molecular Weight ◽  
Polydispersity Index ◽  
Recombinant Bacteria ◽  
E Coli ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Pha Production

ABSTRACT In order to scale up medium-chain-length polyhydroxyalkanoate (mcl-PHA) production in recombinant microorganisms, we generated and investigated different recombinant bacteria containing a stable regulated expression system for phaC1, which encodes one of the mcl-PHA polymerases of Pseudomonas oleovorans. We used the mini-Tn5 system as a tool to constructEscherichia coli 193MC1 and P. oleovoransPOMC1, which had stable antibiotic resistance and PHA production phenotypes when they were cultured in a bioreactor in the absence of antibiotic selection. The molecular weight and the polydispersity index of the polymer varied, depending on the inducer level. E. coli 193MC1 produced considerably shorter polyesters thanP. oleovorans produced; the weight average molecular weight ranged from 67,000 to 70,000, and the polydispersity index was 2.7. Lower amounts of inducer added to the media shifted the molecular weight to a higher value and resulted in a broader molecular mass distribution. In addition, we found that E. coli 193MC1 incorporated exclusively the R configuration of the 3-hydroxyoctanoate monomer into the polymer, which corroborated the enantioselectivity of the PhaC1 polymerase enzyme.

scholarly journals The O-GlcNAc modification promotes terminal differentiation of human corneal epithelial cells

Glycobiology ◽  
2020 ◽  
Vol 30 (11) ◽  
pp. 872-880 ◽  
Author(s):  
Nicole M McColgan ◽  
Marissa N Feeley ◽  
Ashley M Woodward ◽  
Damien Guindolet ◽  
Pablo Argüeso
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Ocular Surface ◽  
Barrier Function ◽  
Terminal Differentiation ◽  
Corneal Epithelial Cell ◽  
Corneal Epithelial Cells ◽  
Corneal Epithelial ◽  
Human Corneal Epithelial Cells ◽  
Glcnac Transferase

Abstract Dynamic modification of nuclear and cytoplasmic proteins with O-linked β-N-acetylglucosamine (O-GlcNAc) plays an important role in orchestrating the transcriptional activity of eukaryotic cells. Here, we report that the O-GlcNAc modification contributes to maintaining ocular surface epithelial homeostasis by promoting mucin biosynthesis and barrier function. We found that induction of human corneal epithelial cell differentiation stimulated the global transfer of O-GlcNAc to both nuclear and cytosolic proteins. Inflammatory conditions, on the other hand, were associated with a reduction in the expression of O-GlcNAc transferase at the ocular surface epithelia. Loss- and gain-of-function studies using small interfering RNA targeting O-GlcNAc transferase, or Thiamet G, a selective inhibitor of O-GlcNAc hydrolase, respectively, revealed that the presence of O-GlcNAc was necessary to promote glycocalyx barrier function. Moreover, we found that Thiamet G triggered a correlative increase in both surface expression of MUC16 and apical epithelial cell area while reducing paracellular permeability. Collectively, these results identify intracellular protein O-glycosylation as a novel pathway responsible for promoting the terminal differentiation of human corneal epithelial cells.

scholarly journals Zdravljenje glavkoma in suho oko

2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Barbara Cvenkel
Keyword(s):  
Ocular Surface ◽  
Clinical Signs ◽  
Tear Film ◽  
Signs And Symptoms ◽  
Surface Damage ◽  
Eye Drops ◽  
Film Instability ◽  
Asymptomatic Patients

Patients with glaucoma have increased prevalence of dry eye (DE) compared to age-matched population without glaucoma. Clinical presentation of DE varies among individuals and may significantly reduce quality of life. The onset and deterioration of DE is caused by the toxic-inflammatory effects of preservatives in eye drops, active substance itself, and added, pharmacologically inactive substances or excipients. Ocular surface changes most frequently include superficial punctate keratitis, tear film instability, and allergic reactions. Despite the lack of symptoms, clinical signs may indicate ocular surface damage. Discordance between signs and symptoms is partly caused by decreased corneal sensitivity induced by neurotoxicity of the preservative benzalkonium chloride (BAK). Therefore, it is important to evaluate ocular surface before initiating glaucoma therapy and during follow-up also in asymptomatic patients. Preservative-free and/or BAK-free therapy is indicated in patients with severe DE and allergy to preservatives, and recommended in patients with DE of moderate severity, blepharitis, in symptomatic patients, before filtering surgery to reduce preoperative inflammation, in those with moderate fluorescein staining of grade 2 on Oxford scheme, and reduced tear film break-up time.

Tailoring length and viscosity of dynamic metallo-supramolecular polymers in solution

RSC Advances ◽  
2016 ◽  
Vol 6 (19) ◽  
pp. 15441-15450 ◽  
Author(s):  
Stefanie Martina Munzert ◽  
Guntram Schwarz ◽  
Dirk G. Kurth
Keyword(s):  
Molecular Weight ◽  
Chain Length ◽  
Coordination Polymers ◽  
Average Molecular Weight ◽  
Supramolecular Polymers ◽  
Supramolecular Coordination

We present a detailed study of metallo-supramolecular coordination polymers (MEPEs) and how to adjust their chain-length and viscosity. A model is established, which can easily be used to prepare MEPEs of desired average molecular weight.

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