Potency of SARS-CoV-2 on Ocular Tissues

The current COVID-19 pandemic has affected more than 100 million people and resulted in morbidity and mortality around the world. Even though the disease caused by SARS-CoV-2 is characterized by respiratory tract involvement, previous and recent data also indicates ocular manifestation. Not surprisingly, cell entry point of the virus, ACE2 receptor, is widely expressed in ocular tissues ranging from conjunctiva to retina. Despite the sensibility of ocular tissues, the sophisticated defense mechanism of the eye might eliminate viral transmission. Nevertheless, the potential of systemic transmission through the nasolacrimal duct may not be eliminated. In the case of ocular involvement, the disease outcomes might be as treatable as conjunctivitis or as serious as retinal degeneration and the treatment regimen vary accordingly. Within these contingencies, our aim with this chapter is to shed light on molecular bases of SARS-CoV-2 infection, systemic invasiveness following ocular transmission, manifestation and permanent effects on ocular tissues

Strategies to Enhance Retention in a Cohort Study Among Adults of Turkish Descent Living in Berlin

Retention is important for statistical power and external validity in long-term cohort studies. The aims of our study were to evaluate different retention strategies within a cohort study of adults of Turkish descent in Berlin, Germany, and to compare participants and non-participants. In 2011-2012, a population-based study was conducted among adults of Turkish descent to primarily examine recruitment strategies. 6 years later, the participants were re-contacted and invited to complete a self-report questionnaire regarding their health status, health care utilization, and satisfaction with medical services. The retention strategy comprised letters in both German and Turkish, phone calls, and home visits (by bilingual staff). We calculated the response rate and retention rate, using definitions of the American Association for Public Opinion Research, as well as the relative retention rate for each level of contact. Associations of baseline recruitment strategy, sociodemographic, migration-related and health-related factors with retention were investigated by logistic regression analysis. Of 557 persons contacted, 249 (44.7%) completed the questionnaire. This was 50.1% of those whose contact information was available. The relative retention rate was lowest for phone calls (8.9%) and highest for home visits (18.4%). Participants were more often non-smokers and German citizens than non-participants. For all remaining factors, no association with retention was found. In this study, among adults of Turkish descent, the retention rate increased considerably with every additional level of contact. Implementation of comprehensive retention strategies provided by culturally matched study personnel may lead to higher validity and statistical power in studies on migrant health issues

Hippocampal volumes and cognitive functions in adult alcoholic patients with adolescent-onset

This study investigated hippocampal volumes and cognitive functions in adult alcoholic patients with adolescent- or late-onset alcohol use. Twenty-one male alcohol dependent inpatients and 13 healthy male controls were enrolled in this study. Cranial magnetic resonance imaging to measure hippocampal volumes and neuropsychological tests were performed in week 4 of abstinence in the patients and controls. The patients were divided into two subgroups (adolescent- and late-onset subgroups) according to the onset age of alcohol use. Alcoholic patients in general had significantly smaller right hippocampal volumes than the healthy controls. Patients' immediate memory, attention, acquisition and working memory subtest scores were inferior to those of the controls. The right hippocampus was significantly smaller in adult alcoholic patients with adolescent-onset use compared to the controls and the late-onset group. There was no significant correlation between neuropsychological test scores and hippocampal volumes. Our results suggest that hippocampal volume loss might be a feature of adolescent-onset alcoholic patients rather than of late-onset ones. (C) 2013 Elsevier Inc. All rights reserved

Enhanced antibacterial and antiparasitic activity of multifunctional polymeric nanoparticles

Due to the resistance to drugs, studies involving the combination and controlled release of different agents are gradually increasing. In this study, two different active ingredients, known to have antibacterial and antiparasitic activities, were encapsulated into single polymeric nanoparticles. After co-encapsulation their antibacterial and antileishmanial activity was enhanced approximately 5 and 250 times, respectively. Antibacterial and antileishmanial activities of caffeic acid phenethyl ester and juglone loaded, multifunctional nanoformulations (CJ4-CJ6-CJ8) were also evaluated for the first time in the literature comparatively with their combined free formulations. The antibacterial activity of the multifunctional nanoformulation (CJ8) were found to have a much higher activity (MIC values 6.25 and 12.5 μg ml-1 for S. aureus and E. coli, respectively) than all other formulations. Similar efficacy for CJ8 was obtained in the antiparasitic study against the Leishmania promastigotes and the IC50 was reduced to 0.1263 μg ml-1. The high activity of multifunctional nanoparticles is not only due to the synergistic effect of the active molecules but also by the encapsulation into polymeric nanoparticles. Therefore, it has been shown in the literature for the first time that the biological activity of molecules whose activity is increased by the synergistic effect can be improved with nanosystems

Hyaluronan-sphingosine polymersomes for treatment of ocular neovascularization: synthesis and evaluation

Ocular neovascularization is a hallmark of several sight-threatening diseases, including diabetic retinopathy and age-related macular degeneration. Currently, available treatments are limited and often associated with side effects. Therefore, a novel approach to ocular neovascularization treatment through utilization of polymersomes from self-assembled sphingosine-grafted hyaluronic acid (HA-Sph) amphiphilic polymers is presented. The polymersomes are generated in spherical morphologies and sizes between 97.95 - 161.9 nm with homogenous size distributions. Experiments reveal that HA-Sph polymersomes, with concentrations ≥150 µg mL−1, significantly inhibit the proliferation of human umbilical vein endothelial cells (HUVECs), while concurrently promoting the proliferation of retinal pigment epithelial cells. The polymersomes demonstrate gradual disintegration in vitro, leading to sustained release of sphingosine, which prolongs the inhibition of HUVEC proliferation (from 87.5% at 24 h to 35.2% viability at 96 h). The efficacy of polymersomes in inhibiting angiogenesis is confirmed through tube formation assay, revealing a substantial reduction in tube length compared to the control group. The findings also validate the ocular penetration capability of polymersomes through ex vivo whole porcine eye ocular penetration study, indicating their suitability for topical administration. Potentially, HA-Sph polymersomes can be harnessed to develop intricate drug delivery systems that protect the retina and effectively treat ocular diseases

Potency of SARS-CoV-2 on ocular tissues

The current COVID-19 pandemic has affected more than 100 million people and resulted in morbidity and mortality around the world. Even though the disease caused by SARS-CoV-2 is characterized by respiratory tract involvement, previous and recent data also indicates ocular manifestation. Not surprisingly, cell entry point of the virus, ACE2 receptor, is widely expressed in ocular tissues ranging from conjunctiva to retina. Despite the sensibility of ocular tissues, the sophisticated defense mechanism of the eye might eliminate viral transmission. Nevertheless, the potential of systemic transmission through the nasolacrimal duct may not be eliminated. In the case of ocular involvement, the disease outcomes might be as treatable as conjunctivitis or as serious as retinal degeneration and the treatment regimen vary accordingly. Within these contingencies, our aim with this chapter is to shed light on molecular bases of SARS-CoV-2 infection, systemic invasiveness following ocular transmission, manifestation and permanent effects on ocular tissues

Niosomal Drug Delivery Systems for Ocular Disease—Recent Advances and Future Prospects

The eye is a complex organ consisting of several protective barriers and particular defense mechanisms. Since this organ is exposed to various infections, genetic disorders, and visual impairments it is essential to provide necessary drugs through the appropriate delivery routes and vehicles. The topical route of administration, as the most commonly used approach, maybe inefficient due to low drug bioavailability. New generation safe, effective, and targeted drug delivery systems based on nanocarriers have the capability to circumvent limitations associated with the complex anatomy of the eye. Nanotechnology, through various nanoparticles like niosomes, liposomes, micelles, dendrimers, and different polymeric vesicles play an active role in ophthalmology and ocular drug delivery systems. Niosomes, which are nano-vesicles composed of non-ionic surfactants, are emerging nanocarriers in drug delivery applications due to their solution/storage stability and cost-effectiveness. Additionally, they are biocompatible, biodegradable, flexible in structure, and suitable for loading both hydrophobic and hydrophilic drugs. These characteristics make niosomes promising nanocarriers in the treatment of ocular diseases. Hereby, we review niosome based drug delivery approaches in ophthalmology starting with different preparation methods of niosomes, drug loading/release mechanisms, characterization techniques of niosome nanocarriers and eventually successful applications in the treatment of ocular disorders

Niosomal drug delivery systems for ocular disease-recent advances and future prospects

The eye is a complex organ consisting of several protective barriers and particular defense mechanisms. Since this organ is exposed to various infections, genetic disorders, and visual impairments it is essential to provide necessary drugs through the appropriate delivery routes and vehicles. The topical route of administration, as the most commonly used approach, maybe inefficient due to low drug bioavailability. New generation safe, effective, and targeted drug delivery systems based on nanocarriers have the capability to circumvent limitations associated with the complex anatomy of the eye. Nanotechnology, through various nanoparticles like niosomes, liposomes, micelles, dendrimers, and different polymeric vesicles play an active role in ophthalmology and ocular drug delivery systems. Niosomes, which are nano-vesicles composed of non-ionic surfactants, are emerging nanocarriers in drug delivery applications due to their solution/storage stability and cost-effectiveness. Additionally, they are biocompatible, biodegradable, flexible in structure, and suitable for loading both hydrophobic and hydrophilic drugs. These characteristics make niosomes promising nanocarriers in the treatment of ocular diseases. Hereby, we review niosome based drug delivery approaches in ophthalmology starting with different preparation methods of niosomes, drug loading/release mechanisms, characterization techniques of niosome nanocarriers and eventually successful applications in the treatment of ocular disorders

A nanogel formulation of anti-VEGF peptide for ocular neovascularization treatment

Age-related macular degeneration (AMD) is an eye disorder that can lead to visual impairment in elder patients, and current treatments include repeated injections of monoclonal antibody-based antivascular endothelial growth factor (anti-VEGF) agents. This study investigates the potential of a nanoformulation of a peptide anti-VEGF molecule for neovascular AMD. Anti-VEGF peptide HRHTKQRHTALH (HRH), which has high affinity to VEGF-Fc receptor, was used as the bioactive agent to control neovascularization of the retina. The nanoformulation consisting of hyaluronic acid nanogel was generated by incorporating divinyl sulfone and cholesterol to increase the stability and control the size of the nanodrug. The encapsulation efficacy of nanogel was 65%, and drug release was 34.72% at the end of 192 h. Obtained nanogels were efficiently internalized in 15 min by human umbilical vascular endothelial cells (HUVECs) and ARPE-19 cells, and results indicate that nanoformulation is not toxic to ARPE-19 cells, whereas it inhibits HUVEC proliferation owing to anti-VEGF peptide in the nanogel structure. In the coculture experiment in which retinal penetration was modeled, it was observed that the nanogel reached HUVECs and negatively affected their proliferation without disturbing the monolayer of ARPE-19 cells. In vivo experiments with chick chorioallantoic membrane revealed that nanogel formulation has higher antiangiogenesis activity compared to free HRH. Additionally, in an oxygen-induced retinopathy model, the excessive growth of blood vessels was notably suppressed in mice treated with HRH-loaded nanogel. This research indicates that nanogels formulated in this study are promising candidates as a topical treatment for AMD