RESUMEN
Age-related macular degeneration (AMD) is a retinal degenerative disorder prevalent in the elderly population, which leads to the loss of central vision. The disease progression can be managed, if not prevented, either by blocking neovascularization ("wet" form of AMD) or by preserving retinal pigment epithelium and photoreceptor cells ("dry" form of AMD). Although current therapeutic modalities are moderately successful in delaying the progression and management of the disease, advances over the past years in regenerative medicine using iPSC, embryonic stem cells, advanced materials (including nanomaterials) and organ bio-printing show great prospects in restoring vision and efficient management of either forms of AMD. This review focuses on the molecular mechanism of the disease, model systems (both cellular and animal) used in studying AMD, the list of various regenerative therapies and the current treatments available. The article also highlights on the recent clinical trials using regenerative therapies and management of the disease.
Asunto(s)
Degeneración Macular , Anciano , Animales , Humanos , Degeneración Macular/patología , Retina/patología , Epitelio Pigmentado de la Retina/patología , Neovascularización Patológica/patologíaRESUMEN
Corneal HSV-1 infections are a leading cause of infectious blindness globally by triggering tissue damage due to the intense inflammation. HSV-1 infections are treated mainly with antiviral drugs that clear the infections but are inefficient as prophylactics. The body produces innate cationic host defence peptides (cHDP), such as the cathelicidin LL37. Various epithelia, including the corneal epithelium, express LL37. cHDPs can cause disintegration of pathogen membranes, stimulate chemokine production, and attract immune cells. Here, we selected GF17, a peptide containing the LL37 fragment with bioactivity but with minimal cytotoxicity, and added two cell-penetrating amino acids to enhance its activity. The resulting GF19 was relatively cell-friendly, inducing only partial activation of antigen presenting immune cells in vitro. We showed that HSV-1 spreads by tunneling nanotubes in cultured human corneal epithelial cells. GF19 given before infection was able to block infection, most likely by blocking viral entry. When cells were sequentially exposed to viruses and GF19, the infection was attenuated but not arrested, supporting the contention that the GF19 mode of action was to block viral entry. Encapsulation into silica nanoparticles allowed a more sustained release of GF19, enhancing its activity. GF19 is most likely suitable as a prevention rather than a virucidal treatment.
Asunto(s)
Herpes Simple , Herpesvirus Humano 1 , Humanos , Péptidos Catiónicos Antimicrobianos/uso terapéutico , Serogrupo , Córnea , Herpesvirus Humano 1/fisiologíaRESUMEN
Pathophysiologic inflammation, e.g., from HSV-1 viral infection, can cause tissue destruction resulting in ulceration, perforation, and ultimately blindness. We developed an injectable Cornea-in-a-Syringe (CIS) sealant-filler to treat damaged corneas. CIS comprises linear carboxylated polymers of inflammation-suppressing 2-methacryloyloxyethyl phosphorylcholine, regeneration-promoting collagen-like peptide, and adhesive collagen-citrate glue. We also incorporated GF19, a modified anti-viral host defense peptide that blocked HSV-1 activity in vitro when released from silica nanoparticles (SiNP-GF19). CIS alone suppressed inflammation when tested in a surgically perforated and HSV-1-infected rabbit corneal model, allowing tissue and nerve regeneration. However, at six months post-operation, only regenerated neocorneas previously treated with CIS with SiNP-GF19 had structural and functional features approaching those of normal healthy corneas and were HSV-1 virus-free. We showed that composite injectable biomaterials can be designed to allow regeneration by modulating inflammation and blocking viral activity in an infected tissue. Future iterations could be optimized for clinical application.
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Introduction: Moderate corneal alkali burns such as those sustained from accidental exposure to household chemicals are treated with topical corticosteroids. Side effects include increased intraocular pressure and slowing of wound healing. Here, we compare the effects of a cannabinoid receptor 2 (CB2r) agonist, TA-A001, that is involved in wound healing with that of the corticosteroid, prednisolone. Methods: TA-A001 was encapsulated with a polymeric micelle comprising polyvinylpyrrolidone: polylactide block copolymers referred to as SmartCelle™ to allow delivery of the very hydrophobic drug. Mouse corneas were given moderate alkali burns. Different doses of TA-A001 of 0.125%, 0.25% and 0.5% were used to treat the burns in comparison to the corticosteroid, prednisolone. Results: TA-A001 at 0.25% and 0.5% allowed for faster wound closure. However, the higher 0.5% dose also induced unwanted neovascularization. By comparison, burned corneas treated with prednisolone showed slower healing as well as disorganization of the cornea. Although 0.25% TA-A001 appeared to produce the most-optimal responses, this dose resulted in marked expression of the macrophage chemoattractant protein, MCP-1. However, there was also an increase in CD163 positive stained M2 anti-inflammatory macrophages in the TA-A001 corneas. TA-A001 treated corneas showed the presence of sensory nerve fibers throughout the corneal epithelium including the superficial cell layers as did Substance P staining. Discussion: We found that TA-A001 at the 0.25% doses was able to modulate inflammation resulting from a moderate alkali burn to the cornea. With more extensive testing, TA-A001 might prove to be a potential alternative to corticosteroids for treating alkali burns or other causes of corneal inflammation.
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Rising cases of Non melanoma skin carcinoma (NMSC) and escalating levels of ultraviolet radiations have underlined a profound correlation with the elevating levels of environmental detoriation and increasing health issues. However, the availability of therapeutics has not aided in controlling the recurrence rates of skin carcinoma. Frequent administration of therapeutics with higher chances of facial deformity escalates the patient's treatment expenses. Thus, this study initiates a low cost effective and biodegradable therapy by exploring four formulations with combinations of silver nanoparticles (AgNPs), sericin (isolated from cocoons of Antherea mylitta) and chitosan. Subsequently, various ethosomal formulations were evaluated as a platform for transdermal delivery vehicle for efficient skin intervention therapeutics. Characterization using UV visible spectroscopy, Dynamic light scattering, Fourier Infrared spectroscopy, X-ray dispersion, Transmission electron microscopy, Fluorescence assisted cell sorting and in vitro studies were done and it was inferenced that equal combination of AgNPs and sericin facilitated to combat the morphological and cellular deformation of the epidermoid A431skin carcinoma cells. The overproduction of superoxide (O2.) and nitric oxide (NO) radicals consequently depolarized the mitochondrial membrane potential triggering apoptosis and necrosis. The in vivo experiments exhibited the stimulation of IgM secretion with T cell-mediated immune response. Therefore, this study proposes a novel approach for treatment of NMSC using biocompatible formulations delivered through ethosomes.