GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    In: Acta Ophthalmologica, Wiley, Vol. 97, No. S263 ( 2019-12)
    Abstract: Primary open‐angle glaucoma (POAG) is a chronic, progressive neuropathy of the optic nerve and one of the major causes of blindness worldwide [1]. ROCK inhibitors such as fasudil are a promising class of drugs on the market allowing a causative therapy of POAG. Unfortunately, a major drawback of topically applied fasudil is its high hydrophilicity and consequently low intraocular bioavailability [1] . In addition, short half‐life severely limits its time of action. Therefore, we propose intravitreal injectable fasudil loaded poly(lactide‐co‐glycolide) microspheres (fasudil‐MS) as promising depot formulation increasing the effect, stability and bioavailability of fasudil to a maximum. In different cell‐based assays the biological activity of fasudil‐MS was tested. Methods Fasudil‐MS were prepared by the water‐in‐oil‐in‐water solvent evaporation technique. Manufactured fasudil‐MS were characterized regarding size by laser diffraction, encapsulation efficiency by HPLC and in vitro release. Measurement of biologic activity of released drug was performed in different cell‐based assays. Therefore, preliminary cell studies were established with free fasudil and the glaucomatous factors connective tissue growth factor (CTGF) and transforming growth factor‐β2 (TGF‐β2) to analyze cell contractility and expression of a‐smooth muscle actin (a‐SMA) by qPCR. Results Fasudil‐MS had a size of 20‐25µm and spherical shape. Fasudil was released in a controlled biphasic releasing profile. In preliminary experiments, fasudil demonstrated its ability to diffuse through the vitreous body and was able to reduce the cell contractility as well as the gene expression of a‐SMA induced by CTGF and TGF‐β2. Conclusion The proposed formulation could be a promising strategy increasing therapy effectiveness. Reference Mietzner R, Breunig M. Causative glaucoma treatment: promising targets and delivery systems. Drug Discov Today. 2019.
    Type of Medium: Online Resource
    ISSN: 1755-375X , 1755-3768
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 2466981-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    In: Pharmaceuticals, MDPI AG, Vol. 15, No. 1 ( 2021-12-24), p. 18-
    Abstract: A root cause for the development and progression of primary open-angle glaucoma might be the loss of the Schlemm’s canal (SC) cell function due to an impaired Angiopoietin-1 (Angpt-1)/Tie2 signaling. Current therapeutic options fail to restore the SC cell function. We propose Angpt-1 mimetic nanoparticles (NPs) that are intended to bind in a multivalent manner to the Tie2 receptor for successful receptor activation. To this end, an Angpt-1 mimetic peptide was coupled to a poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) block co-polymer. The modified polymer allowed for the fabrication of Angpt-1 mimetic NPs with a narrow size distribution (polydispersity index 〈 0.2) and the size of the NPs ranging from about 120 nm (100% ligand density) to about 100 nm (5% ligand density). NP interaction with endothelial cells (HUVECs, EA.hy926) as surrogate for SC cells and fibroblasts as control was investigated by flow cytometry and confocal microscopy. The NP–cell interaction strongly depended on the ligand density and size of NPs. The cellular response to the NPs was investigated by a Ca2+ mobilization assay as well as by a real-time RT-PCR and Western blot analysis of endothelial nitric oxide synthase (eNOS). NPs with a ligand density of 25% opposed VEGF-induced Ca2+ influx in HUVECs significantly which could possibly increase cell relaxation and thus aqueous humor drainage, whereas the expression and synthesis of eNOS was not significantly altered. Therefore, we suggest Angpt-1 mimetic NPs as a first step towards a causative therapy to recover the loss of SC cell function during glaucoma.
    Type of Medium: Online Resource
    ISSN: 1424-8247
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2193542-7
    SSG: 15,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    In: Pharmaceutics, MDPI AG, Vol. 12, No. 8 ( 2020-07-27), p. 706-
    Abstract: Rho-associated protein kinase (ROCK) inhibitors allow for causative glaucoma therapy. Unfortunately, topically applied ROCK inhibitors suffer from high incidence of hyperemia and low intraocular bioavailability. Therefore, we propose the use of poly (lactide-co-glycolide) (PLGA) microspheres as a depot formulation for intravitreal injection to supply outflow tissues with the ROCK inhibitor fasudil over a prolonged time. Fasudil-loaded microspheres were prepared by double emulsion solvent evaporation technique. The chemical integrity of released fasudil was confirmed by mass spectrometry. The biological activity was measured in cell-based assays using trabecular meshwork cells (TM cells), Schlemm’s canal cells (SC cells), fibroblasts and adult retinal pigment epithelium cells (ARPE-19). Cellular response to fasudil after its diffusion through vitreous humor was investigated by electric cell-substrate impedance sensing. Microspheres ranged in size from 3 to 67 µm. The release of fasudil from microspheres was controllable and sustained for up to 45 days. Released fasudil reduced actin stress fibers in TM cells, SC cells and fibroblasts. Decreased collagen gel contraction provoked by fasudil was detected in TM cells (~2.4-fold), SC cells (~1.4-fold) and fibroblasts (~1.3-fold). In addition, fasudil readily diffused through vitreous humor reaching its target compartment and eliciting effects on TM cells. No negative effects on ARPE-19 cells were observed. Since fasudil readily diffuses through the vitreous humor, we suggest that an intravitreal drug depot of ROCK inhibitors could significantly improve current glaucoma therapy particularly for patients with comorbid retinal diseases.
    Type of Medium: Online Resource
    ISSN: 1999-4923
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2527217-2
    SSG: 15,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    In: Small, Wiley, Vol. 14, No. 50 ( 2018-12)
    Abstract: Glaucoma is the second leading cause of blindness worldwide, often associated with elevated intraocular pressure. Connective tissue growth factor (CTGF) is a mediator of pathological effects in the trabecular meshwork (TM) and Schlemm's canal (SC). A novel, causative therapeutic concept which involves the intracameral delivery of small interfering RNA against CTGF is proposed. Layer‐by‐layer coated nanoparticles of 200–260 nm with a final layer of hyaluronan (HA) are developed. The HA‐coating should provide the nanoparticles sufficient mobility in the extracellular matrix and allow for binding to TM and SC cells via CD44. By screening primary TM and SC cells in vitro, in vivo, and ex vivo, the validity of the concept is confirmed. CD44 expression is elevated in glaucomatous versus healthy cells by about two‐ to sixfold. CD44 is significantly involved in the cellular uptake of HA‐coated nanoparticles. Ex vivo organ culture of porcine, murine, and human eyes demonstrates up to threefold higher accumulation of HA compared to control nanoparticles and much better penetration into the target tissue. Gene silencing in primary human TM cells results in a significant reduction of CTGF expression. Thus, HA‐coated nanoparticles combined with RNA interference may provide a potential strategy for glaucoma therapy.
    Type of Medium: Online Resource
    ISSN: 1613-6810 , 1613-6829
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2168935-0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    In: Pharmaceutics, MDPI AG, Vol. 13, No. 6 ( 2021-06-17), p. 901-
    Abstract: In glaucoma therapy, nanoparticles (NPs) are a favorable tool for delivering drugs to the outflow tissues of the anterior chamber of the eye where disease development and progression take place. In this context, a prerequisite is an efficient enrichment of NPs in the trabecular meshwork with minimal accumulation in off-target tissues such as the cornea, lens, iris and ciliary body. We evaluated the optimal size for targeting the trabecular meshwork by using gold NPs of 5, 60, 80 and 120 nm with a bare surface (AuNPs) or coated with hyaluronic acid (HA-AuNPs). NPs were compared regarding their colloidal stability, distribution in the anterior chamber of the eye ex vivo and cellular uptake in vitro. HA-AuNPs demonstrated an exceptional colloidal stability. Even after application into porcine eyes ex vivo, the HA coating prevented an aggregation of NPs inside the trabecular meshwork. NPs with a diameter of 120 nm exhibited the highest volume-based accumulation in the trabecular meshwork. Off-target tissues in the anterior chamber demonstrated an exceptionally low gold content. Our findings are particularly important for NPs with encapsulated anti-glaucoma drugs because a higher particle volume would be accompanied by a higher drug payload.
    Type of Medium: Online Resource
    ISSN: 1999-4923
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527217-2
    SSG: 15,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Online Resource
    Online Resource
    Proceedings of the National Academy of Sciences ; 2013
    In:  Proceedings of the National Academy of Sciences Vol. 110, No. 15 ( 2013-04-09), p. 6115-6120
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 110, No. 15 ( 2013-04-09), p. 6115-6120
    Abstract: To date, diseases affecting vascular structures in the posterior eye are mostly treated by laser photocoagulation and multiple intraocular injections, procedures that destroy healthy tissue and can cause vision-threatening complications. To overcome these drawbacks, we investigate the feasibility of receptor-mediated nanoparticle targeting to capillary endothelial cells in the retina after i.v. application. Cell-binding studies using microvascular endothelial cells showed receptor-specific binding and cellular uptake of cyclo(RGDfC)-modified quantum dots via the αvβ3 integrin receptor. Conversely, Mueller cells and astrocytes, representing off-target cells located in the retina, revealed only negligible interaction with nanoparticles. In vivo experiments, using nude mice as the model organism, demonstrated a strong binding of the ligand-modified quantum dots in the choriocapillaris and intraretinal capillaries upon i.v. injection and 1-h circulation time. Nontargeted nanoparticles, in contrast, did not accumulate to a significant amount in the target tissue. The presented strategy of targeting integrin receptors in the retina could be of utmost value for future intervention in pathologies of the posterior eye, which are to date only accessible with difficulty.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    RVK:
    RVK:
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2013
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...