Characterization of liposomal carriers for the trans-scleral transport of Ranibizumab

Anti-angiogenic biomolecules in neovascular age-related macular degeneration; therapeutics and drug delivery systems

Blindness in the elderly is often caused by age-related macular degeneration (AMD). The advanced type of AMD known as neovascular AMD (nAMD) has been linked to being the predominant cause of visual impairment in these people. Multiple neovascular structures including choroidal neovascular (CNV) membranes, fluid exudation, hemorrhages, and subretinal fibrosis, are diagnostic of nAMD. These pathological alterations ultimately lead to anatomical and visual loss. It is known that vascular endothelial growth factor (VEGF), a type of proangiogenic factor, mediates the pathological process underlying nAMD. Therefore, various therapies have evolved to directly target the disease. In this review article, an attempt has been made to discuss general explanations about this disease, all common treatment methods based on anti-VEGF drugs, and the use of drug delivery systems in the treatment of AMD. Initially, the pathophysiology, angiogenesis, and different types of AMD were described. Then we described current treatments and future treatment prospects for AMD and outlined the advantages and disadvantages of each. In this context, we first examined the types of therapeutic biomolecules and anti-VEGF drugs that are used in the treatment of AMD. These biomolecules include aptamers, monoclonal antibodies, small interfering RNAs, microRNAs, peptides, fusion proteins, nanobodies, and other therapeutic biomolecules. Finally, we described drug delivery systems based on liposomes, nanomicelles, nanoemulsions, nanoparticles, cyclodextrin, dendrimers, and composite vehicles that are used in AMD therapy.

Design of liposomal nanocarriers with a potential for combined dexamethasone and bevacizumab delivery to the eye

Clinicians face numerous challenges when delivering medications to the eyes topically because of physiological barriers, that can inhibit the complete dose from getting to the intended location. Due to their small size, the ability to deliver drugs of different polarities simultaneously, and their biocompatibility, liposomes hold great promise for ocular drug delivery. This study aimed to develop and characterise a dual loaded liposome formulation encapsulating Bevacizumab (BEV) and Dexamethasone (DEX) that possessed the physicochemical attributes suitable for topical ocular delivery. Liposomes were prepared by using thin film hydration followed by extrusion, and the formulations were optimised using a design of experiments approach. Physicochemical characterisation along with cytocompatibility and bioactivity of the formulations were assessed. Liposomes were successfully prepared with a particle size of 139 ± 2 nm, PDI 0.03 ± 0.01 and zeta potential -2 ± 0.7 mV for the optimised formulation. BEV and DEX were successfully encapsulated into the liposomes with an encapsulation efficiency of 97 ± 0.5 % and 26 ± 0.5 %, respectively. A sustained release of BEV was observed from the liposomes and the bioactivity of the formulation was confirmed using a wound healing assay. In summary, a potential topical eye drop drug delivery system, which can co-load DEX and BEV was developed and characterised for its potential to be used in ocular drug delivery.

Age-Related Macular Degeneration - Therapies and Their Delivery

Age-related macular degeneration (ARMD) is a degenerative ocular disease that is the most important cause of irreversible vision loss in old-aged people in developed countries. Around fifty percent of vision impairments in developed countries are due to ARMD. It is a multifaceted disease that is associated with both genetic and environmental risk factors. The most important treatments option for ARMD includes laser photocoagulation, photodynamic therapy (PDT), Anti-VEGF Injections, and combination therapies. In this review, we also propose that topical ocular drug delivery with nanocarriers has more attention for the treatment of ARMD. The nanocarriers were specially designed for enhanced corneal residential time, prolonged drug release and action, and minimizing the frequency of administrations. Different types of nanocarriers were developed for the topical ocular delivery system, such as nanomicelles, nanoemulsions, nanosuspensions, liposomes, and polymeric nanoparticles. These topical ocular nanocarriers were administered topically, and they can fix the hydrophobic substances, increase solubility and improve the bioavailability of an administered drug. Hence the topical ocular delivery systems with nanocarriers provide a safe and effective therapeutic strategy and promising tool for the treatment of posterior segment ocular diseases ARMD.

Protein Corona Formation on Lipid Nanoparticles Negatively Affects the NLRP3 Inflammasome Activation

The interaction between lipid nanoparticles (LNPs) and serum proteins, giving rise to a unique identification in the form of the protein corona, has been shown to be associated with novel recognition by cell receptors. The presence of the corona enveloping the nanoparticle strongly affects the interplay with immune cells. The immune responses mediated by protein corona can affect nanoparticle toxicity and targeting capabilities. But the intracellular signaling of LNPs after corona formation resulting in the change of nanoparticles' ability to provoke immune responses remains unclear. Therefore, a more systematic and delineated approach must be considered to present the correlation between corona complexes and the shift in nanoparticle immunogenicity. Here, we studied and reported the inhibiting effect of the absorbed proteins on the LNPs on the NLRP3 inflammasome activation, a key intracellular protein complex that modulates several inflammatory responses. Ionizable lipid as a component of LNP was observed to play an important role in modulating the activation of NLRP3 inflammasome in serum-free conditions. However, in the presence of serum proteins, the corona layer on LNPs caused a significant reduction in the inflammasome activation. Reduction in the lysosomal rupture after treatment with corona-LNPs significantly reduced inflammasome activation. Furthermore, a strong reduction of cellular uptake in macrophages after the corona formation was observed. On inspecting the uptake mechanisms in macrophages using transport inhibitors, lipid formulation was found to play a critical role in determining the endocytic pathways for the LNPs in macrophages. This study highlights the need to critically analyze the protein interactions with nanomaterials and their concomitant adaptability with immune cells to evaluate nano-bio surfaces and successfully design nanomaterials for biological applications.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Preparation of DRV Liposomes

Dried reconstituted vesicle (DRV) liposomes are formulated under mild conditions. The method has the capability to entrap substantially higher amounts of hydrophilic solutes, compared to other passive-loading liposome preparation methods. These characteristics make this liposome type ideal for entrapment of labile substances, such as peptides, proteins, or DNA's (or other nucleotides or oligonucleotides), or in general biopharmaceuticals and sensitive drugs. In this chapter, all possible types of DRV liposomes (in respect to the encapsulated molecule characteristics and/or their applications in therapeutics) are introduced, and preparation methodologies (for each type) are described in detail.

Factors That Can Prolong Ocular Treatment Duration in Age-Related Macular Degeneration

Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are used to treat wet age-related macular degeneration (wAMD); however, they are associated with a considerable treatment burden and poor real-world outcomes. The molecular size and charge of anti-VEGF agents influence drug pharmacokinetics in the vitreous and peak drug efficacy. This article reviews the established and novel strategies to prolong drug action, in the vitreal cavity, and thus reduce dosing frequency. Increased ocular residency can be attained by increasing drug size as with large molecules, such as KSI-301; adding polyethylene glycol to pegcetacoplan (APL-2) or avacincaptad pegol to increase molecular size; or binding to other targets that increase molecular size, such as vitreal albumin in the case of BI-X. Faricimab is a bispecific antibody in which the fragment crystallizable portion is engineered to prolong ocular residency and reduce systemic exposure. Conversely, small VEGF-binding molecules, such as brolucizumab, can be administered at higher clinical doses, with the potential for prolonged clinical activity versus larger molecules. Other important considerations include sustained drug delivery routes, such as the ranibizumab port delivery system or subconjunctival or suprachoroidal injection. More effective and longer-lasting treatments are needed for wAMD to prolong drug action and reduce dosing frequency. Several strategies are under investigation and the prevention of vision loss in patients with AMD or other retinal diseases may be attainable in the near future.

Controlled released naringin-loaded liposome/sucrose acetate isobutyrate hybrid depot for osteogenesis in vitro and in vivo

Introduction: A common problem in bone tissue engineering is that the burst release of active osteogenic factors is not beneficial for osteogenesis. This study aimed to prepare naringin (Ng) liposomes to reduce the burst release of Ng and improve new bone formation. Methods: We synthesized Ng liposomes using the thin-film hydration method. Drug-encapsulation efficacy experiments were conducted using the ultracentrifugation technique. The morphology and size distributions of freezedried liposomes were determined by transmission electron microscopy and dynamic light scattering. The Ng liposomes and Ng-lipo/sucrose acetate isobutyrate (SAIB) depots were characterized using Fourier transform infrared spectroscopy and in vitro release studies. After implantation of the Ng-lipo/SAIB depots, in vitro osteoblast-liposome interactions and in vivo osteogenesis were tested. Results: The formulation of freeze-dried Ng liposomes via an optimized recipe yielded nanosized (136.9 nm) negatively charged particles with a high encapsulation efficiency (~76.3%). Their chemical structure did not change after adding SAIB to the Ng liposomes. The burst release was reduced dramatically from 74.4% to 23.7%. In vivo, after 8 weeks, the new bone formation rate in the calvarial defects of Sprague-Dawley rats receiving Ng-lipo/SAIB was 57% compared with 25.18% in the control group (p = .0003). Discussion: Our results suggested that Ng-lipo/SAIB hybrid depots could serve as candidate materials for drug delivery in bone regeneration applications.

Monoclonal antibodies in diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR), as one of the main complications of diabetes, is among the leading causes of blindness and visual impairment worldwide.

AREAS COVERED

Current clinical therapies include photocoagulation, vitrectomy, and anti-vascular endothelial growth factor (VEGF) therapies. Bevacizumab and ranibizumab are two monoclonal antibodies (mAbs) inhibiting angiogenesis. Intravitreal ranibizumab and bevacizumab can decrease the rate of blindness and retinal thickness, and improve visual acuity whether as monotherapy or combined with other treatments. They can increase the efficacy of other treatments and decrease their adverse events. Although administered intravitreally, they also might enter the circulation and cause systemic effects. This study is aimed to review our current knowledge about mAbs, bevacizumab and ranibizumab, in DR including superiorities, challenges, and limitations. Meanwhile, we tried to shed light on new ideas to overcome these limitations. Our latest search was done in April 2021 mainly through PubMed and Google Scholar. Relevant clinical studies were imported.

EXPERT OPINION

Future direction includes detection of more therapeutic targets considering other components of DR pathophysiology and shared pathogenesis of DR and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, the treat-and-extend regimen, and new ways of drug delivery and other routes of ocular drug administration.

Nanotechnology for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a degenerative eye disease that is the leading cause of irreversible vision loss in people 50 years and older. Today, the most common treatment for AMD involves repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs. However, the existing expensive therapies not only cannot cure this disease, they also produce a variety of side effects. For example, the number of injections increases the cumulative risk of endophthalmitis and other complications. Today, a single intravitreal injection of gene therapy products can greatly reduce the burden of treatment and improve visual effects. In addition, the latest innovations in nanotherapy provide the best drug delivery alternative for the treatment of AMD. In this review, we discuss the development of nano-drug delivery systems and gene therapy strategies for AMD in recent years. In addition, we discuss some novel targeting strategies and the potential application of these delivery methods in the treatment of AMD. Finally, we also propose that the combination of CRISPR/Cas9 technology with a new non-viral delivery system may be promising as a therapeutic strategy for the treatment of AMD.

Management of toxic optic neuropathy via a combination of Wharton's jelly-derived mesenchymal stem cells with electromagnetic stimulation

PURPOSE

To investigate the effect of the combination of Wharton's jelly derived mesenchymal stem cells (WJ-MSC) and high frequency repetitive electromagnetic stimulation (rEMS) in the therapy of toxic optic neuropathies with severe symptoms after the available current therapy modalities which were unsucessful.

MATERIAL AND METHODS

This prospective, open-label clinical phase-3 study was conducted at Ankara University Faculty of Medicine, Department of Ophthalmology between April 2019 and April 2021. Thirty-six eyes of 18 patients with toxic optic neuropathy (TON) were included in the study. Within 1-3 months after the emergency interventions, patients with various degrees of sequela visual disturbances were studied in this clinical trial. The cases were divided into three groups according to similar demographic characteristics. Group 1: Consists of 12 eyes of 12 patients treated with the WJ-MSC and rEMS combination in one eye. Group 2: Consists of 12 eyes of 12 patients treated with only rEMS in one eye. Group 3: Consists of 12 eyes of six patients treated with only WJ-MSC in both eyes. The course was evaluated by comparing the quantitive functional and structural assessment parameters measured before and at the fourth month of applications in each group.

RESULTS

The mean best corrected visual acuity (BCVA) delta change percentages of the groups can be ranked as: Group 1 (47%) > Group 3 (32%) > Group 2 (21%). The mean fundus perimetry deviation index (FPDI) delta change percentages of the groups can be ranked as: Group 1 (95%) > Group 2 (33%) > Group 3 (27%). The mean ganglion cell complex (GCC) thickness delta change (decrease in thickness) percentages can be ranked as: Group 1 (- 21%) > Group 3 (- 15%) > Group 2 (- 13%). The visual evoked potential (VEP) P100 latency delta change percentages of the groups can be ranked as: Group 1 (- 18%) > Group 3 (- 10%) > Group 2 (- 8%). The P100 amplitude delta change percentages of the groups can be ranked as: Group 1 (105%) > Group 3 (83%) > Group 2 (24%).

CONCLUSION

Toxic optic neuropathies are emergent pathologies that can result in acute and permanent blindness. After poisoning with toxic substances, progressive apoptosis continues in optic nerve axons and ganglion cells. After the proper first systemic intervention in intensive care clinic, the WJ-MSC and rEMS combination seems very effective in the short-term period in cases with TON. To prevent permanent blindness, a combination of WJ-MSC and rEMS application as soon as possible may increase the chance of success in currently untreatable cases. Trial Registration ClinicalTrials.gov ID: NCT04877067.

In vivo fate of liposomes after subconjunctival ocular delivery

Subconjunctival administration of nanocarriers presents an alternative drug delivery strategy to overcome blood-ocular barriers to enhance drug bioavailability to specific parts of the eye. Using fiberoptic Confocal Laser Microendoscopy (CLM) and radiotracing, we describe the effects of charge, size, cholesterol content and lipid saturation on the ocular and corporal distribution of liposome nanocarriers in live mouse models. Positively charged or large (>250 nm) liposomes exhibit sustained ocular residence times in and around the injection site; cholesterol loading slows down this clearance, whereas lipid saturation accelerates clearance. Neutral, negatively charged, or smaller sized liposomes distribute to the limbus, rich in stem cells and blood capillaries. Differential lymphatic and systemic clearance from the eye to corporeal tissues was also observed across formulations. These results demonstrate the need to optimize liposome design for control over temporal and spatial nanocarrier bioavailability and clearance from the eye for improved efficacy and safety of ocular therapeutics.

Recent advances in intraocular and novel drug delivery systems for the treatment of diabetic retinopathy

Introduction: Diabetic retinopathy (DR) is associated with damage to the retinal blood vessels that lead eventually to vision loss. The existing treatments of DR are invasive, expensive, and cumbersome. To overcome challenges associated with existing therapies, various intraocular sustained release and novel drug delivery systems (NDDS) have been explored.Areas covered: The review discusses recently developed intraocular devices for sustained release of drugs as well as novel noninvasive drug delivery systems that have met a varying degree of success in local delivery of drugs to retinal circulation.Expert opinion: The intraocular devices have got very good success in providing sustained release of drugs in patients. The development of NDDS and their application through the ocular route has certainly provided an edge to treat DR over existing therapies such as anti-VEGF administration but their success rate is quite low. Moreover, most of them have proved to be effective only in animal models. In addition, the extent of targeting the drug to the retina still remains variable and unpredictable. The toxicity aspect of the NDDS has generally been neglected. In order to have successful commercialization of nanotechnology-based innovations well-designed clinical research studies need to be conducted to evaluate their clinical superiority over that of the existing formulations.

Crosslink among phosphatidylinositol-3 kinase/Akt, PTEN and STAT-5A signaling pathways post liposomal galactomannan hepatocellular carcinoma therapy

Liposomal drug-delivery systems (LDDs) provide a promising opportunity to precisely target organs, improve drug bioavailability and reduce systemic toxicity. On the other hand, PI₃K/Akt signaling pathways control various intracellular functions including apoptosis, invasion and cell growth. Hyper activation of PI3K and Akt is detected in some types of cancer that posses defect in PTEN. Tracking the crosstalk between PI3K/Akt, PTEN and STAT 5A signaling pathways, in cancer could result in identifying new therapeutic agents. The current study, identified an over view on PI3K/Akt, PTEN and STAT-5A networks, in addition to their biological roles in hepatocellular carcinoma (HCC). In the current study galactomannan was extracted from Caesalpinia gilliesii seeds then loaded in liposomes. Liposomes were prepared employing phosphatidyl choline and different concentrations of cholesterol. HCC was then induced in Wistar albino rats followed by liposomal galactomannan (700 ± 100 nm) treatment. Liver enzymes as well as antioxidants were assessed and PI3K/Akt, PTEN and STAT-5A gene expression were investigated. The prepared vesicles revealed entrapment efficiencies ranging from 23.55 to 69.17%, and negative zeta potential values. The optimum formulation revealed spherical morphology as well as diffusion controlled in vitro release pattern. Liposomal galactomannan elucidated a significant reduction in liver enzymes and MDA as well as PI3K/Akt, PTEN and STAT 5A gene expression. A significant elevation in GST and GSH were deduced. In conclusion, Liposomal galactomannan revealed a promising candidate for HCC therapy.

A review of the clinical applications of drug delivery systems for the treatment of ocular anterior segment inflammation

Ocular anterior segment inflammation is a medical problem that is seen in cases of cataract surgery and non-infectious anterior uveitis. Inadequately treated anterior segment inflammation can lead to sight-threatening conditions such as corneal oedema, glaucoma and cystoid macular oedema. The mainstay of treatment for anterior segment inflammation is topical steroid eye-drops. However, several drawbacks limit the critical value of this treatment, including low bioavailability, poor patient compliance, relatively difficult administration manner and risk of blurring of vision and ocular irritation. A drug delivery system (DDS) that can provide increased bioavailability and sustained delivery while being specifically targeted towards inflamed ocular tissue can potentially replace daily eye-drops as the gold standard for management of anterior segment inflammation. The various DDS for anti-inflammatory drugs for the treatment of anterior segment inflammation are listed and summarised in this review, with a focus on commercially available products and those in clinical trials. Dextenza, INVELTYS, Dexycu and Bromsite are examples of DDS that have enjoyed success in clinical trials leading to FDA approval. Nanoparticles and ocular iontophoresis form the next wave of DDS that have the potential to replace topical steroids eye-drops as the treatment of choice for anterior segment inflammation. With the current relentless pace of ophthalmic drug delivery research, the pursuit of a new standard of treatment that eliminates the problems of low bioavailability and patient compliance may soon be realised.

Management of retinitis pigmentosa by Wharton's jelly derived mesenchymal stem cells: preliminary clinical results

PURPOSE

The aim of this study is to determine if umbilical cord Wharton's jelly derived mesenchymal stem cells implanted in sub-tenon space have beneficial effects on visual functions in retinitis pigmentosa patients by reactivating the degenerated photoreceptors in dormant phase.

MATERIAL AND METHODS

This prospective, open-label, phase-3 clinical trial was conducted between April of 2019 and October of 2019 at Ankara University Faculty of Medicine, Department of Ophthalmology. 32 RP patients (34 eyes) were included in the study. The patients were followed for 6 months after the Wharton's jelly derived mesenchymal stem cell administration, and evaluated with consecutive examinations. All patients underwent a complete routine ophthalmic examination, and best corrected visual acuity, optical coherens tomography angiography, visual field, multifocal and full-field electroretinography were performed. The quantitative results were obtained from a comparison of the pre-injection and final examination (6th month) values.

RESULTS

The mean best corrected visual acuity was 70.5 letters prior to Wharton's jelly derived mesenchymal stem cell application and 80.6 letters at the 6th month (p = 0.01). The mean visual field median deviation value was 27.3 dB before the treatment and 24.7 dB at the 6th month (p = 0.01). The mean outer retinal thickness was 100.3 μm before the treatment and 119.1 μm at 6th month (p = 0.01). In the multifocal electroretinography results, P1 amplitudes improved in ring1 from 24.8 to 39.8 nv/deg2 (p = 0.01), in ring2 from 6.8 to 13.6 nv/deg2 (p = 0.01), and in ring3 from 3.1 to 5.7 nv/deg2 (p = 0.02). P1 implicit times improved in ring1 from 44.2 to 32.4 ms (p = 0.01), in ring2 from 45.2 to 33.2 ms (p = 0.02), and in ring3 from 41.9 to 32.4 ms (p = 0.01). The mean amplitude improved in 16 Tds from 2.4 to 5.0 nv/deg2 (p = 0.01) and in 32 Tds from 2.4 to 4.8 nv/deg2 (p = 0.01) in the full-field flicker electroretinography results. Full field flicker electroretinography mean implicit time also improved in 16 Tds from 43.3 to 37.9 ms (p = 0.01). No ocular or systemic adverse events related to the two types of surgical methods and/or Wharton's jelly derived mesenchymal stem cells itself were observed during the follow-up period.

CONCLUSION

RP is a genetic disorder that can result in blindness with outer retinal degeneration. Regardless of the type of genetic mutation, sub-tenon Wharton's jelly derived mesenchymal stem cell administration appears to be an effective and safe option. There are no serious adverse events or ophthalmic / systemic side effects for 6 months follow-up. Although the long-term adverse effects are still unknown, as an extraocular approach, subtenon implantation of the stem cells seems to be a reasonable way to avoid the devastating side effects of intravitreal/submacular injection. Further studies that include long-term follow-up are needed to determine the duration of efficacy and the frequency of application.

TRIAL REGISTRATION

SHGM56733164. Redistered 28 January 2019 https://shgm.saglik.gov.tr/organ-ve-doku-nakli-koordinatorlugu/56733164/203 E.507.

Management of Deep Retinal Capillary Ischemia by Electromagnetic Stimulation and Platelet-Rich Plasma: Preliminary Clinical Results

INTRODUCTION

To investigate the efficacy of retinal electromagnetic stimulation and sub-tenon autologous platelet-rich plasma in the treatment of deep retinal capillary ischemia.

METHODS

The study included 28 eyes of 17 patients aged 15-76 years (mean 37.9 years) who had deep retinal capillary ischemia. Patients who had acute-onset paracentral scotoma in the last 1 month were included in the study between January 2018 and January 2019. The diagnosis of deep retinal capillary ischemia was based on clinical history and typical findings of optical coherence tomography angiography. The eyes were divided into three groups: group 1 (n = 7 eyes) received electromagnetic stimulation alone; group 2 (n = 7 eyes) received electromagnetic stimulation and sub-tenon autologous platelet-rich plasma injection; group 3 had no intervention and served as a control group (n = 14 eyes). The patients underwent ten sessions of electromagnetic stimulation in groups 1 and 2. Sub-tenon autologous platelet-rich plasma injection was performed immediately after the first, fifth, and tenth sessions of electromagnetic stimulation in group 2. The deep retinal capillary density and best corrected visual acuity changes were investigated before and after treatment at the first month.

RESULTS

The mean deep retinal capillary density was 52.0% before electromagnetic stimulation and 56.1% after ten sessions of application in group 1; this improvement was statistically significant (p = 0.01). In the combined treatment group (group 2), the mean deep retinal capillary density was 46.9% before the treatment and 56.5% after the treatment; this increase was also statistically significant (p = 0.01). Statistically significant best corrected visual acuity improvement (p = 0.01) could be achieved only in group 2. The combined treatment was significantly superior (p < 0.01) to treatment with only electromagnetic stimulation regarding best corrected visual acuity and deep retinal capillary density. In the control group (group 3), there was no statistically significant change (p = 0.09) in the mean deep retinal capillary density and best corrected visual acuity.

CONCLUSION

Treatment of the underlying cause is a priority in the treatment of deep retinal capillary ischemia. However, in the acute period, local ischemia treatment is necessary to prevent permanent retinal damage and scotomas. In mild cases, only electromagnetic stimulation, which is non-invasive and easy to use, might have a beneficial effect on deep retinal capillary density. In more severe cases, sub-tenon fresh autologous platelet-rich plasma injection together with electromagnetic stimulation may be more effective in the treatment of local ischemia of the retina in order to augment the response.

FUNDING

The Rapid Service Fees were funded by the Ankara University Tecnopolis Institute.

CLINICAL TRIAL REGISTRATION

titck.gov.tr identifier, 2018-136.

Complement system and age-related macular degeneration: drugs and challenges

Age-related macular degeneration (AMD) is directly attributable to vision loss, posing significant pressure on public health. AMD is recognized to be a multi-factorial disease and among them, complement system is under heated discussion in recent years. In this review, we start with an overview of complement pathways involved in AMD and their therapies correspondingly. Finally, we discuss the development of the therapeutics existed now. Also, we enclose a list of drugs undergoing clinical trials.

Posterior segment drug delivery for the treatment of exudative age-related macular degeneration and diabetic macular oedema

Inhibitors of vascular endothelial growth factors are used to treat a myriad of retinal conditions, including exudative age-related macular degeneration (AMD), diabetic macular oedema (DME) and diabetic retinopathy. Although effective, long-term efficacy is limited by the need for frequent and invasive intravitreal injections. The quest for sustained action therapeutics that can be delivered to target tissue in the least invasive manner is an arduous endeavour that has ended in premature failure for several technologies in Phase II or III trials. Nevertheless, there have been promising preclinical studies, and more are on the horizon: port delivery systems for the treatment of exudative AMD have entered Phase III trials and a wide array of preclinical studies have demonstrated the potential for nanoparticles, such as liposomes, dendrimers and cell penetrating peptides to deliver therapeutics into the posterior segment via minimally invasive routes. In this review, we discuss the challenges posed by ocular barriers for drug penetration and present the recent advancements of the most pertinent drug delivery platforms with a focus on the treatment of exudative AMD and DME.

Liver-targeted delivery of liposome-encapsulated curcumol using galactosylated-stearate

Liver-targeted drug delivery improves the efficacy of anti-liver cancer agents and reduces systemic toxicity by limiting the bioavailability of these drugs to within tumors. Liver targeting reagents with galactose residues, which selectively combine to asialoglyco protein receptors, have previously been used to improve liposome-encapsulated drug accumulation within liver cells. They lead to a reduction in liver cancer cell growth and have been used to cure certain hepatic diseases. In the present study, curcumol, which is the primary active component of Chinese traditional medicine Rhizoma zedoariae, was encapsulated in galactosylated-liposomes to enhance its anti-liver cancer efficacy. Galactosylated-liposomes and normal liposomes were labeled with propidium iodide. Galactosylated-liposomes with increasing concentrations of galactosylated-stearate (Gal-s) had a notably increased level of uptake in HepG2 cells (hepatoblastoma) compared with SGC-7901 (gastric cancer) and A549 (non-small cell lung cancer) cells. When the percentage of Gal-s reached 20%, liposome uptake plateaued. In the in vitro anti-liver cancer experiment, the anti-liver cancer efficacy of galactosylated-curcumol-liposomes increased significantly more compared with normal curcumol liposomes and free curcumol as indicated by cell survival rate and lactate dehydrogenase release rate. Collectively, these results demonstrate that galactosylated-liposomes are able to enhance the in vitro liver-targeting effect and anti-liver cancer efficacy of curcumol.

Extended Duration Vascular Endothelial Growth Factor Inhibition in the Eye: Failures, Successes, and Future Possibilities

Vascular endothelial growth factor (VEGF) plays a pivotal role in the development of neovascularization and edema from several common chorioretinal vascular conditions. The intravitreally injected drugs (aflibercept, bevacizumab, conbercept, pegaptanib, and ranibizumab) used to treat these conditions improve the visual acuity and macular morphology in most patients. Monthly or bimonthly injections were administered in the phase III pivotal trials but physicians usually individualize therapy with pro re nata (PRN) or treat and extend regimens. Despite these lower frequency treatment regimens, frequent injections and clinic visits are still needed to produce satisfactory outcomes. Newly developed drugs and refillable reservoirs with favorable pharmacokinetic profiles may extend durations of action and require fewer office visits. However, we have learned from previous experiences that the longer durations of action seen in strategically designed phase III trials often do not translate to less frequent injections in real-life clinical practice. Unfortunately, long-acting therapies that produce soluble VEGF receptors (encapsulated cell technology and adenovirus injected DNA) have failed in phase II trials. The development of longer duration therapies remains a difficult and frustrating process, and frequent drug injections are likely to remain the standard-of-care for years to come.