Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.

Extracellular and intraneuronal accumulation of amyloid-beta aggregates has been demonstrated to be involved in the pathogenesis of Alzheimer's disease (AD). However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of macromolecules has deleterious effects on cellular functions. Mitochondria were found to be the target for amyloid-beta, and mitochondrial dysfunction is well documented in AD. In the present study we have shown for the first time that Aβ 1–42 bound to a peptide comprising the amino-terminal region of cytochrome c oxidase subunit 1. Phage clone, selected after screening of a human brain cDNA library expressed on M13 phage and bearing a 61 amino acid fragment of cytochrome c oxidase subunit 1, bound to Aβ 1–42 in ELISA as well as to Aβ aggregates present in AD brain. Aβ 1–42 and cytochrome c oxidase subunit 1 co-immunoprecipitated from mitochondrial fraction of differentiated human neuroblastoma cells. Likewise, molecular dynamics simulation of the cytochrome c oxidase subunit 1 and the Aβ 1–42 peptide complex resulted in a reliable helix-helix interaction, supporting the experimental results. The interaction between Aβ 1–42 and cytochrome c oxidase subunit 1 may explain, in part, the diminished enzymatic activity of respiratory chain complex IV and subsequent neuronal metabolic dysfunction observed in AD.

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The current pandemic is caused by the coronavirus disease 2019 (COVID-19), which is, in turn, induced by a novel coronavirus (SARS-CoV-2) that triggers an acute respiratory disease. In recent years, the emergence of SARS-CoV-2 is the third highly pathogenic event and large-scale epidemic affecting the human population. It follows the severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. This novel SARS-CoV-2 employs the angiotensinconverting enzyme 2 (ACE2) receptor, like SARS-CoV, and spreads principally in the respiratory tract. The viral spike (S) protein of coronaviruses facilities the attachment to the cellular receptor, entrance, and membrane fusion. The S protein is a glycoprotein and is critical to elicit an immune response. Glycosylation is a biologically significant post-translational modification in virus surface proteins. These glycans play important roles in the viral life cycle, structure, immune evasion, and cell infection. However, it is necessary to search for new information about viral behavior and immunological host's response after SARS-CoV-2 infection. The present review discusses the implications of the CoV-2 S protein glycosylation in the SARS-CoV-2/ACE2 interaction and the immunological response. Elucidation of the glycan repertoire on the spike protein can propel research for the development of an appropriate vaccine.

To evaluate indications and outcomes of pediatric keratoplasty in a tertiary eye center, and identify factors that affect visual outcomes.We performed a retrospective review of penetrating keratoplasty in children aged 0 to 18 years between 1995 and 2011 in the Asociación para Evitar la Ceguera en México IAP, Hospital “Dr. Luis Sánchez Bulnes”.A total of 574 penetrating keratoplasties were performed during the study interval. Median follow-up was 5.0 years. Main indications included keratoconus (55.58%), postherpetic scarring (9.58%), traumatic opacities (7.49%), and bullous keratopathy (6.09%). Rejection rates at 5 years were 27% overall, and among indications, keratoconus showed the best graft survival at 60-months follow-up (85%). The percentage of patients with best corrected visual acuity (BCVA) posttransplant >20/400 at 5 years in the nonrejection group was 81.25% and 82.74% in < and > 10 years of age (YOA) groups, respectively, versus a BCVA posttransplant > 20/400 at 5 years in the rejection group of 53.68% and 51.72% in < and > 10 YOA groups, respectively. There was a statistically significant reduced rejection rate between genders at 18 months of follow-up, favoring males.Despite being considered a high-risk procedure in children, penetrating keratoplasty can achieve good results, especially in patients with keratoconus. It can achieve significative improvements of visual acuity, provided there is an adequate follow-up and treatment adherence.

AbstractExtracellular and intracellular accumulation of amyloid beta 1-42 peptide in different states of aggregation has been involved in the development and progression of Alzheimer’s disease. However, the precise mechanisms involved in amyloid beta peptide neurotoxicity have not been fully understood. There exists a wide variety of studies demonstrating the binding of amyloid beta peptide to a great variety of macromolecules and that such associations affect the cellular functions. This type of association involves proteins and receptors anchored to the plasma membrane of neurons or immune cells of the central nervous system as well as intracellular proteins that can alter intracellular transport, activate signaling pathways or affect proper mitochondrial function. In this review, we present some examples of such associations and the role played by these interactions, which are generally involved in the pathological progression of Alzheimer’s disease.

Purpose To examine the current knowledge about the age-related processes in the anterior segment of the eye at a biological, clinical, and molecular level. Methods We reviewed the available published literature that addresses the aging process of the anterior segment of the eye and its associated molecular and physiological events. We performed a search on PubMed, CINAHL, and Embase using the MeSH terms “eye,” “anterior segment,” and “age.” We generated searches to account for synonyms of these keywords and MESH headings as follows: (1) “Eye” AND “ageing process” OR “anterior segment ageing” and (2) “Anterior segment” AND “ageing process” OR “anterior segment” AND “molecular changes” AND “age.” Results. Among the principal causes of age-dependent alterations in the anterior segment of the eye, we found the mutation of the TGF-β gene and loss of autophagy in addition to oxidative stress, which contributes to the pathogenesis of degenerative diseases. Conclusions In this review, we summarize the current knowledge regarding some of the molecular mechanisms related to aging in the anterior segment of the eye. We also introduce and propose potential roles of autophagy, an important mechanism responsible for maintaining homeostasis and proteostasis under stress conditions in the anterior segment during aging.

Chronic exposure to low doses of ozone similar to a day of high pollution in Mexico City causes a state of oxidative stress. This produces a progressive neurodegeneration in hippocampus of rats exposed to the gas. The aim of this study was to analyze the effect of chronic exposure on the changes in the blood-brain barrier in rats exposed to low doses of ozone. Method: each group received one of the following treatments, control group received air without ozone, and groups 2, 3, 4, 5, and 6 received ozone doses of 0.25 ppm for 4 h daily during 7, 15, 30, 60 and 90 days respectively. Each group was processed to inmunohistochemical technique against of the following antibody: bloodbrain barrier, guanylyl cyclase, Iba-1, GFAP, NFκ-B, TNF-α. The results show that there is a correlation between the time exposure of ozone and the progressive damage, on the blood-brain barrier rupture, finally causing edema of endothelial cell, increase in guanylyl cyclase type 1, thickening of the processes and astrocytes foot, and an increase in the expression of factors NFκ-B and TNF-α at 30 and 60 days of exposure to this gas. All the above indicates that the chronic state of oxidative stress causes a neurodegeneration process, accompanied by disruption of the blood-brain barrier likely to occur in the Alzheimer's disease.