Atrial fibrillation (AF) is a progressive arrhythmia with underlying mechanisms that are not fully elucidated, partially due to lack of reliable and affordable animal models. Here, we introduce a system for long-term assessment of AF susceptibility (substrate) in ambulatory rats implanted with miniature electrodes on the atrium. Rats were subjected to excessive aldosterone (Aldo) or solvent only (Sham). An additional group was exposed to myocardial infarction (MI). AF substrate was tested two-and four-weeks post implantation and was also compared with implanted rats early post-implantation (Base). Aldo and MI increased the AF substrate and atrial fibrosis. In the MI group only, AF duration was correlated with the level of atrial fibrosis and was inversely correlated with systolic function. Unexpectedly, Shams also developed progressive AF substrate relative to Base individuals. Further studies indicated that serum inflammatory markers (IL-6, TNF-alpha) were not elevated in the shams. In addition, we excluded anxiety\depression due to social-isolation as an AF promoting factor. Finally, enhanced biocompatibility of the atrial electrode did not inhibit the gradual development of AF substrate over a testing period of up to 8 weeks. Overall, we successfully validated the first system for long-term AF substrate testing in ambulatory rats.Atrial fibrillation (AF) is a growing epidemic, entailing substantial economic costs, morbidity and mortality 1,2 . The pathophysiology of AF is multi-factorial in nature. It involves sources of sustained rapid electrical activity that can trigger arrhythmic episodes as well as pathological mechanisms which alter the electrical and structural substrate for AF in the atrial tissue 3-7 . A full understanding of the molecular mechanisms by which various underlying conditions and factors converge to progressively promote AF substrate is still lacking [8][9][10] . Drugs aimed to target the atrial remodeling (upstream therapies) are attractive new options to prevent AF perpetuation. However, early pre-clinical testing of such drugs is currently difficult due to the absence of reliable and affordable animal models.Traditionally, AF-related models have relied solely on large animals exposed to atrial tachypacing or heart failure 11 . However, over the last two decades, rodents have been increasingly used to study various mechanistic aspects in the pathophysiology of AF 12-18 , and the possibility of using rodents to test new therapies seems attractive. However, several technical limitations constrain the widespread utility of rodents in AF research. Particularly, the small and delicate rodent atria render the implantation of chronic pacing and recording
Purpose Vernal keratoconjunctivitis (VKC) is a severe chronic allergic inflammation of the ocular surface with episodes of acute exacerbations, that primarily affects children and young adults. Although the etiology and pathogenesis of VKC remain unclear, studies have suggested that environmental factors may be involved. This study aims to investigate the association between exposure to meteorological and environmental factors and the incidence of VKC exacerbations. Methods This study was conducted in southern Israel, which is a semi-arid, hot, and dry climate with frequent dust storms. Patients diagnosed with VKC were recruited for the study. VKC exacerbations were identified as the need for medical intervention. Pollutants measured included nitrogen dioxide (NO 2 ), ozone (O 3 ), particulate matter (PM 10 and PM 2.5 ), sulfur dioxide (SO 2 ), relative humidity (RH), temperature, and solar radiation (SR). To assess the association between VKC exacerbations and exposure to different pollutants, a case-crossover analysis was conducted. We also stratified the analysis by sex, age, ethnicity, immigration status, and social state score. Results Our results demonstrated that the pollutants NO 2 , O 3 , and PM 10 were associated with VKC exacerbations with odds ratio (OR) = 2.17 (95% confidence interval [CI] =1.40 to 3.04), OR = 2.28 (95% CI = 1.30 to 3.39), and OR = 1.89 (95% CI = 1.06 to 2.74). Other pollutants PM 2.5 , temperature, and solar radiation were also independently associated with incidence of exacerbations with OR = 1.15 (95% CI = 0.87 to 1.50), OR = 1.75 (95% CI = 1.16 to 2.65), and OR = 1.37 (95% CI = 1.01 to 1.63) and had varying effects in different demographic strata. Conclusions The environmental parameters, NO 2 , O 3 , PM 10 , PM 2.5 , temperature, and solar radiation were found to be significantly associated with VKC exacerbations, with NO 2 , O 3 , and PM 10 showing the strongest associations. Our findings suggest that environmental factors should be considered when developing strategies to prevent and manage VKC exacerbations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.