Air pollution, a major global health concern, is well known for its impact on respiratory and cardiovascular systems. However, its effects on ocular health remain poorly understood. Exploring the potential pathways through which airborne particles interact with and enter the eye is essential to uncover the mechanisms underlying pollution-related ocular diseases. The importance of these questions is underscored by the seamless continuity between the eye's neural structures and the brain, forming a unified channel that drains through multiple tributaries into the cervical lymph nodes. In this review we explore several potential pathways through which particles may access the eye's neural structures. The first is the well-established pulmonary route, where inhaled pollutants induce inflammation via the circulatory system; the second a novel extrapulmonary pathway involving direct transmission through the olfactory-nervous system. This review is organized into three sections: an overview of ambient air pollution, a review of studies on air pollution's effects in ocular diseases; and, discussion derived from this body of research. Advancing our understanding of air pollution's interact with and impact on ocular health is essential for the development of targeted strategies to protect vision and reduce environmental health risks.

Exposure to air pollution has been a significant challenge in large cities as São Paulo, Brazil, particularly for individuals exercising outdoors. The increasing on ventilation (VE) during physical effort can lead to greater pollutant inhalation. Our goal in the present study evaluated whether air pollution exposure affects venous blood gases and if it has an impact on performance during a 50-km cycling time trial (TT). Ten male cyclists performed the TT in an environmental chamber under TRAP and filtered air conditions. Venous blood samples collected pre- and post-TT were analyzed for pH, PvCO2 (partial pressure of carbon dioxide in venous blood), PvO2 (partial pressure of oxygen in venous blood) hematocrit (Htc), hemoglobin (Hb), and oxygen saturation (SvO2). PM2.5 levels were significantly lower in filtered air (11.2 ± 4.7 μm/m3) than in TRAP (34.6 ± 10.8 μm/m3). There was no significant difference in mean power output between conditions (p = 0.907, d = 0.038). Blood gas parameters showed no condition effect or interaction, but time significantly affected PvO2 (p = 0.04), Hb (p < 0.01), Htc (p < 0.01), and PvCO2 (p = 0.02). These findings suggest recreationally trained cyclists experience no performance impairment under TRAP, with minimal changes in venous blood gas parameters.

Anti-VEGF (vascular endothelial growth factor) drugs such as aflibercept (AFL) and bevacizumab (BVZ) inhibit pathological neo-angiogenesis and vascular permeability in retinal vascular diseases. As cytokines and growth factors are produced by Müller glial cells under stressful and pathological conditions, we evaluated the in vitro effect of AFL (Eylea®, 0.5 mg/mL) and BVZ (Avastin®, 0.5 mg/mL) on cell viability/metabolism, and cytokine/growth factor production by Müller cells (MIO-M1) under cobalt chloride (CoCl2)-induced hypoxia after 24h, 48h and 72h. Cell viability/metabolism were analyzed by Trypan Blue and MTT assays and cytokine/growth factors in supernatants by Luminex xMAP-based multiplex bead-based immunoassay. Cell viability increased with AFL at 48h and 72h and decreased with BVZ or hypoxia at 24h. BVZ-treated cells showed lower cell viability than AFL at all exposure times. Cell metabolism increased with AFL but decreased with BVZ (72h) and hypoxia (48h and72h). As expected, AFL and BVZ decreased VEGF levels. AFL increased PDGF-BB, IL-6 and TNF-α (24h) and BVZ increased PDGF-BB (72h). Hypoxia reduced IL-1β, -6, -8, TNF-α and PDGF-BB at 24h, and its suppressive effect was more prominent than AFL (EGF, PDGF-BB, IL-1β, IL-6, IL-8, and TNF-α) and BVZ (PDGF-BB and IL-6) effects. Hypoxia increased bFGF levels at 48h and 72h, even when combined with anti-VEGFs. However, the stimulatory effect of BVZ predominated over hypoxia for IL-8 and TNF-α (24h), as well as for IL-1β (72h). Thus, AFL and BVZ exhibit distinct exposure times effects on MIO-M1 cells viability, metabolism, and cytokines/growth factors. Hypoxia and BVZ decreased MIO-M1 cell viability/metabolism, whereas AFL likely induced gliosis. Hypoxia resulted in immunosuppression, and BVZ stimulated inflammation in hypoxic MIO-M1 cells. These findings highlight the complexity of the cellular response as well as the interplay between anti-VEGF treatments and the hypoxic microenvironment.

Air pollution (AP) is one of the main recent concerns in reproductive healthy due to its potential to promote negative outcomes during pregnancy and male and female fertility. Several studies have demonstrated that AP exposure has been linked to increased embryonic implantation failures, alterations in embryonic, fetal and placental development. For a well-succeeded implantation, both competent blastocyst and receptive endometrium are required. Based on the lack of data about the effect of AP in endometrial receptivity, this study aimed to evaluate he particulate matter (PM) exposure impact on uterine receptive markers in mice and associate the alterations to increased implantation failures due to AP. For this study, ten dams per group were exposed for 39 days to either filter (F) or polluted air (CAP). At fourth gestational day (GD4), females were euthanized. Morphological, ultrastructural, immunohistochemical and molecular analysis of uterine and ovarian samples were performed. CAP-exposed females presented a reduced number of corpus luteum; glands and epithelial cells were increased with pinopodes formation impairment. Immunohistochemistry analysis revealed decreased LIF protein levels. These preliminary data suggests that PM exposure may exert negative effects on endometrial receptivity by affecting crucial parameters to embryonic implantation as uterine morphological differentiation, corpus luteum quantity and LIF expression during implantation window.

The epiretinal membrane is a fibrocontractile tissue that forms on the inner surface of the retina, causing visual impairment ranging from mild to severe, and even retinal detachment. Müller glial cells actively participate in the formation of this membrane. Current research is constantly seeking for new therapeutic approaches that aim to prevent or treat cellular dysfunctions involved in the progression of this common fibrosis condition. The Rho GTPases signaling pathway regulates several processes associated with the epiretinal membrane, such as cell proliferation, migration, and contraction. Rho kinase (ROCK), an effector of the RhoA GTPase, is an interesting potential therapeutic target. This study aimed to evaluate the effects of a ROCK inhibitor (Y27632) on human Müller cells viability, growth, cytoskeletal organization, expression of extracellular matrix components, myofibroblast differentiation, migration, and contractility. Müller cells of the MIO-M1 lineage were cultured and treated for different periods with the inhibitor. Viability was evaluated by MTT assay and trypan blue exclusion method, and growth was evaluated by growth curve and BrdU incorporation assay. The actin cytoskeleton was stained with fluorescent phalloidin, intermediate filaments and microtubules were analyzed with immunofluorescence for vimentin and α-tubulin. Gene and protein expression of collagens I and V, laminin and fibronectin were evaluated by rt-PCR and immunofluorescence. Chemotactic and spontaneous cell migration were studied by transwell assay and time-lapse observation of live cells, respectively. Cell contractility was assessed by collagen gel contraction assay. The results showed that ROCK inhibition by Y27632 did not affect cell viability, but decreased cell growth and proliferation after 72 h. There was a change in cell morphology and organization of F-actin, with a reduction in the cell body, disappearance of stress fibers and formation of long, branched cell extensions. Microtubules and vimentin filaments were also affected, possibly because of F-actin alterations. The inhibitor also reduced gene expression and immunoreactivity of smooth muscle α-actin, a marker of myofibroblasts. The expression of extracellular matrix components was not affected by the inhibitor. Chemotactic cell migration showed no significant changes, while cell contractility was substantially reduced. No spontaneous migration of MIO-M1 cells was observed. In conclusion, pharmacological inhibition of ROCK in Müller cells could be a potentially promising approach to treat epiretinal membranes by preventing cell proliferation, contractility and transdifferentiation, without affecting cell viability.

Aging increases the risks for developing fibrocontractile membranes on the retina, which causes significant macular distortion, as in the idiopathic epiretinal membrane (iERM). Retinal Muller glial cells are components of these membranes and may play a key role in the iERM pathogenesis. The transforming growth factor-beta (TGF-beta) induces Muller cell transdifferentiation into myofibroblast, reducing glial cell markers (glutamine synthetase, GS, and glial fibrillary acidic protein, GFAP) and increasing alpha-smooth muscle actin (alpha-SMA). Our aim was to investigate the effect of the TGF-beta inhibitor galunisertib (LY2157299) on the glial-mesenchymal transition and contraction of Muller cells.MIO-M1 human Muller cells were treated with TGF-beta 1 (10 ng/mL), galunisertib (5, 10 and 20 mu M) and TGF beta 1+galunisertib for 24h and 48h. Galunisertib cytotoxicity was analyzed by MTT and trypan blue, and TGF-beta 1 blockade by phospho-SMAD3 immunofluorescence. Caspase-3 (cell death indicator), GS, GFAP and alpha-SMA expression was examined by immunofluorescence, Western blotting, and qPCR analysis. Cell contractility was determined by collagen gel contraction assay with Muller cells incorporated.Galunisertib did not show cytotoxicity at the concentrations evaluated and maintained the Muller cells phenotype, ensuring the GS expression. Galunisertib inhibited the TGF-beta 1 pathway by decreasing phosphoSMAD3 immunoreactivity, attenuated the alpha-SMA expression, and prevented the contraction of Muller cells in collagen gel.Although more studies are needed, in vitro assays suggest that galunisertib may be a potential candidate to attenuate the formation of fibrocontractile membranes and prevent retinal detachment and consequent loss of vision.

Previous studies have shown that immunosuppressive drugs impair the airway mucociliary clearance of rats. However, considering the high specificity of basiliximab (BSX) and the absence of studies reporting its side effects, our aim was to investigate whether BSX, associated or not with triple therapy, impairs the mucociliary system. Forty rats were divided into 4 groups: Control, BSX, Triple, and BSX + Triple. After 15 days of treatment, animals were euthanized and the ciliary beating frequency (CBF), mucociliary transport velocity (MCTV), neutral and acid mucin production, Muc5ac and Muc5b gene expression, inflammatory cell number, and interleukin (IL)-6 concentration were analyzed. CBF and MCTV were lower in Triple and BSX + Triple groups (p < 0.05). Neutral mucin percentage was higher in Triple group (p < 0.05), and acid mucin percentage was higher in Triple and BSX + Triple groups (p < 0.05). The Muc5ac and Muc5b gene expression was higher in Triple and BSX + Triple groups (p < 0.05). Animals from Triple and BSX + Triple groups presented fewer mononuclear cells (p < 0.05). The number of polymorphonuclear cells was higher in the Triple group (p < 0.05). In the analysis of inflammatory cells in the blood, there was a decrease in lymphocytes and an increase in neutrophils in the Triple and BSX + Triple groups (p < 0.05). The concentration of IL-6 significantly increased in the animals of the Triple and BSX + Triple groups (p < 0.05). BSX did not change the mucociliary apparatus of rats.

High-intensity interval exercise (HIIE) is an effective non-pharmacological tool for improving physiological responses related to health. When HIIE is performed in urban centers, however, the exerciser is exposed to traffic-related air pollution (TRAP), which is associated with metabolic, anti-inflammatory imbalance and cardiovascular diseases. This paradoxical combination has the potential for conflicting health effects. Thus, the aim of this study was to determine the effects of HIIE performed in TRAP exposure on serum cytokines, non-target metabolomics and cardiovascular parameters. Fifteen participants performed HIIE in a chamber capable to deliver filtered air (FA condition) or non-filtered air (TRAP condition) from a polluted site adjacent to the exposure chamber. Non-target blood serum metabolomics, blood serum cytokines and blood pressure analyses were collected in both FA and TRAP conditions at baseline, 10 min after exercise, and 1 h after exercise. The TRAP increased IL-6 concentration by 1.7 times 1 h after exercise (p < 0.01) and did not change the anti-inflammatory balance (IL-10/TNF-α ratio). In contrast, FA led to an increase in IL-10 and IL-10/TNF-α ratio (p < 0.01), by 2.1 and 2.3 times, respectively. The enrichment analysis showed incomplete fatty acid metabolism under the TRAP condition (p < 0.05) 10 min after exercise. There was also an overactivity of ketone body metabolism (p < 0.05) at 10 min and at 1 h after exercise with TRAP. Exercise-induced acute decrease in systolic blood pressure (SBP) was not observed at 10 min and impaired at 1 h after exercise (p < 0.05). These findings reveal that TRAP potentially attenuates health benefits often related to HIIE. For instance, the anti-inflammatory balance was impaired, accompanied by accumulation of metabolites related to energy supply and reduction to exercise-induced decrease in SBP.

The aim of the present study was to analyze the effects of traffic-related air pollution (TRAP) on markers of inflammatory, neuroplasticity, and endurance performance-related parameters in recreationally trained cyclists who were adapted to TRAP during a 50-km cycling time trial (50-km cycling TT). Ten male cyclists performed a 50-km cycling TT inside an environmental chamber located in downtown Sao Paulo (Brazil), under TRAP or filtered air conditions. Blood samples were obtained before and after the 50-km cycling TT to measure markers of inflammatory [interleukin-6 (IL-6), C-reactive protein (CRP), interleukin-10 (IL-10), intercellular adhesion molecule-1 (ICAM-1)] and neuroplasticity [brain-derived neurotrophic factor (BDNF)]. Rating of perceived exertion (RPE), heart rate (HR), and power output (PO) were measured throughout the 50-km cycling TT. There were no significant differences between experimental conditions for responses of IL-6, CRP, and IL-10 (P > 0.05). When compared with exercise-induced changes in filtered air condition, TRAP provoked greater exercise-induced increase in BDNF levels (TRAP = 3.3 ± 2.4-fold change; Filtered = 1.3 ± 0.5-fold change; P = 0.04) and lower exercise-induced increase in ICAM-1 (Filtered = 1.1 ± 0.1-fold change; TRAP = 1.0 ± 0.1-fold change; P = 0.01). The endurance performance-related parameters (RPE, HR, PO, and time to complete the 50-km cycling TT) were not different between TRAP and filtered air conditions (P > 0.05). These findings suggest that the potential negative impacts of exposure to pollution on inflammatory, neuroplasticity, and performance-related parameters do not occur in recreationally trained cyclists who are adapted to TRAP.

Although the exposure to traffic-related air pollution (TRAP) has emerged as one of main problem worldwide to inhabitants' health in urban centers, its impact on metabolic responses during exercise is poorly understood. The aim of study was to characterize the profile of non-target serum metabolomics during prolonged exercise per -formed under TRAP conditions. Ten healthy men completed two 90 min constant-load cycling trials under conditions of either TRAP or filtered air. Experimental trials were performed in a chamber located on an avenue with a high volume of vehicle traffic. Blood samples were taken at 30 min, 60 min, and 90 min of exercise. Based on Nuclear Magnetic Resonance metabolomics, the non-target analysis was used to assess the metabolic profile. Twelve, 16 and 18 metabolites were identified as discriminants. These were: at 30 min of exercise, the coefficient of determination (R-2) 0.98, the predictive relevance, (Q(2)) 0.12, and the area under the curve (AUC) 0.91. After 60 min of exercise: (R-2: 0.99, Q(2): 0.09, AUC: 0.94); and at 90 min of exercise (R-2: 0.91, Q(2): <0.01, AUC: 0.89), respectively. The discriminant metabolites were then considered for the target analysis, which demonstrated that the metabolic pathways of glycine and serine metabolism (p = 0.03) had been altered under TRAP conditions at 30 min of exercise; arginine and proline metabolism (p = 0.04) at 60 min of exercise; and glycolysis (p = 0.05) at 90 min of exercise. The present results suggest that exposure to TRAP during prolonged exercise leads to a significant change in metabolomics, characterized by a transitional pattern and lastly, impairs the glucose metabolism.

Idiopathic epiretinal membrane (iERM) is a fibrocellular proliferation on the inner surface of the retina, which leads to decreased visual acuity and even central visual loss. As iERM is associated to advanced age and posterior vitreous detachment, a higher prevalence is expected with increasing life expectancy and aging of the global population. Although various cell types of retinal and extra-retinal origin have been described in iERMs (Müller glial cells, astrocytes, hyalocytes, retinal pigment epithelium cells, myofibroblasts, and fibroblasts), myofibroblasts have a central role in collagen production and contractile activity. Thus, myofibroblast differentiation is considered a key event for the iERM formation and progression, and fibroblasts, Müller glial cells, hyalocytes, and retinal pigment epithelium have been identified as myofibroblast precursors. On the other side, the different cell types synthesize growth factors, cytokines, and extracellular matrix, which have a crucial role in ERM pathogenesis. In the present review, the major cellular components and their functions are summarized, and their possible roles in the iERM formation are discussed. By exploring in detail the cellular and molecular aspects of iERM, we seek to contribute for better understanding of this fibrotic disease and the origin of myofibroblasts, which may eventually drive to more targeted therapeutic approaches.

Pre-harvest burning of sugarcane fields produces large amounts of air pollutants which are known to cause health problems, including ocular surface abnormalities. In this study, we evaluated the effect of biomass burning on mucus quality and mucin gene expression (MUC1, MUC5AC, MUC16) in the conjunctiva of sugarcane workers (SWs) and residents of an adjacent town (RTs). Impression cytology samples of the inferior tarsal and bulbar conjunctiva of 78 SWs and 32 RTs were collected before (T1) and immediately after (T2) a 6-month harvest period. The neutral, acid and total mucus content of goblet cells was determined by PAS and AB staining. The levels of MUC5AC, MUC1 and MUC16 mRNA in the conjunctiva were measured by real-time PCR. Compared to RTs, SWs had higher levels of bulbar acid mucus and MUC16 mRNA and tarsal MUC5AC mRNA at T2 and lower levels of neutral mucus at T1 and T2. In the SW group, MUC1 mRNA levels were higher at T2 than at T1, but the levels of neutral and acid mucus were similar. In the RT group, acid mucus decreased and neutral mucus increased in the bulbar and tarsal conjunctiva at T2. In conclusion, our findings show that sugarcane harvesting is associated with abnormalities in mucus quality and content and changes in mucin mRNA levels on the ocular surface. This may help explain the ocular inflammatory signs and symptoms observed in subjects exposed to air pollutants and high temperatures from sugarcane biomass burning.

Diesel exhaust particles (DEP) are known to generate reactive oxygen species in the respiratory system, triggering cells to activate antioxidant defence mechanisms, such as Keap1-Nrf2 signalling and autophagy. The aim of this study was to investigate the relationship between the Keap1-Nrf2 signalling and autophagy pathways after DEP exposure. BEAS-2B cells were transfected with silencing RNA (siRNA) specific to Nrf2 and exposed to DEP. The relative levels of mRNA for Nrf2, NQO1, HO-1, LC3B, p62 and Atg5 were determined using RT-PCR, while the levels of LCB3, Nrf2, and p62 protein were determined using Western blotting. The autophagy inhibitor bafilomycin caused a significant decrease in the production of Nrf2, HO-1 and NQO1 compared to DEPs treatment, whereas the Nrf2 activator sulforaphane increased the LC3B (p = 0.020) levels. BEAS-2B cells exposed to DEP at a concentration of 50 μg/mL for 2 h showed a significant increase in the expression of LC3B (p = 0.001), p62 (p = 0.008), Nrf2 (p = 0.003), HO-1 (p = 0.001) and NQO1 (p = 0.015) genes compared to control. In siRNA-transfected cells, the LC3B (p < 0.001), p62 (p = 0.001) and Atg5 (p = 0.024) mRNA levels and the p62 and LC3II protein levels were decreased, indicating that Nrf2 modulated the expression of autophagy markers (R < 1). These results imply that, in bronchial cells exposed to DEP, the Nrf2 system positively regulates autophagy to maintain cellular homeostasis.

The aim of this study was to investigate, in a well-controlled experimental environment, whether air pollution from an urban center would affect inflammatory and cardiorespiratory responses during prolonged moderate exercise (i.e., 90 min). Ten healthy men performed two experimental trials under filtered and polluted air, inside an environmental chamber located in Sao Paulo downtown, Brazil. Blood samples were obtained at rest, 30, 60, and 90 min of the exercise to determine the serum cytokines concentration, while arterial pressure was recorded immediately after the exercise. The serum cytokines were not altered until 60 min of exercise for both conditions (P > 0.05). Otherwise, at 90 min of exercise, the IL-6 (P = 0.047) and vascular endothelial growth factor (VEGF) (P = 0.026) were significantly higher and IL-10 tended to decrease (P = 0.061) in polluted air condition compared to filtered air condition. In addition, both systolic (P = 0.031) and diastolic (P = 0.009) arterial pressure were higher in polluted air condition than filtered air condition. These findings demonstrate that the exercise of longer duration (i.e., 90 min), but not of shorter duration (i.e., <60 min), performed in vehicular air pollution condition results in pronounced pro-inflammatory and increased arterial pressure responses.

Air pollution affects all major urban centers, particularly megacities with populations greater than 10 million people. Vehicular and industrial emissions are among the most important sources of air pollutants in these cities. Air pollution composition, dose, and time of exposure can cause differential effects on human health. We have evaluated the genotoxic effects of air pollution (PM2.5 and NO2) on Sao Paulo city workers. Fifty-seven male individuals, 28-66 years old, with occupational exposure to air pollution, participated in this study; all worked daily outdoor shifts in Sao Paulo. Participants were recruited from three occupations: traffic controllers (n = 18); taxi drivers (n = 21); and workers at the Forestry Institute (n = 18). These workers were classified into two groups based on their workplace locations: Downtown Group (DT): traffic controllers and taxi drivers; Outskirts of Town Group (OT): workers at the Forestry Institute. Individual samplers of air pollution (Harvard air impactor) were used to collect PM2.5 and NO2 pollutants. Genotoxicity analysis (micronucleus test) was performed on buccal mucosa epithelial cells and peripheral blood lymphocytes. PM2.5 concentrations were significantly different between the groups (DT = 32.92 mu g m(-3), OT = 25.77 mu g m(-3); p = 0.03); however, no difference was observed in NO2 concentrations. Micronucleus frequencies in both buccal mucosa (DT = 2.78%, OT = 1.16%; p < 0.0001) and in peripheral lymphocytes (DT = 1.51%, OT = 0.73%; p < 0.0001) were significantly different between the groups. We observed a direct correlation between the individual dose of PM2.5 and micronucleus frequency in the buccal mucosa (p = 0.0021). Our results indicate that workers in the most urban areas of Sao Paulo are exposed to higher concentrations of PM2.5 and showed higher micronucleus frequencies in both buccal mucosa and lymphocytes.

Background: Aerobic exercise is recommended to improve health. However, the increased ventilation might increase the doses of inhaled air pollutants, negating the health benefits in highly polluted areas. Our objective was to estimate the inhaled dose of air pollutants during two simulated exercise sessions at cleanest and dirtiest cities reported by World Health Organization (WHO) considering air quality. Methods: Minute ventilation data were extracted from laboratory-based exercise of 116 incremental running tests and used to calculate total ventilation of a hypothetical 30-min moderate continuous exercise routine. Afterwards, total ventilation values were combined with particulate matter (PM) data reported by the WHO for the 10 cleanest and 10 dirtiest cities, to calculate inhaled doses and the relative risk of all-cause mortality by exercising in different air pollution concentrations. Findings: The dirtiest cities are located at less developed countries compared to cleanest cities. The inhaled dose of PM2.5 and PM10 were significantly higher in the dirtiest cities compared to the cleanest cities at rest and exercise, and significantly higher during exercise compared to the rest at dirtiest cities. The relative risk of all-cause mortality analysis showed that, while exercise in the cleanest cities improved health benefits throughout up to 90 min, there were no further health benefits after 15 min of exercise in the dirtiest cities, and the air pollution health risks surpassed the exercise benefits after 75 min. Interpretation: Our findings suggest that a traditional 30-min of moderate aerobic exercise session might induce inhalation of high levels of pollutants when performed at dirtiest cities. Considering several adverse health effects from air pollutants inhalation, so the results suggest that the air pollution levels of the cities should be taken into account for physical exercise recommendations.