Biology subjects

Briones, A. M.

Publications and source records attributed to Briones, A. M..

2 recordsLinked to original sources

bioRxiv2025

CERIUM OXIDE NANOPARTICLES ATTENUATE THE PRO-ARRHYTHMIC EFFECT OF DIESEL EXHAUST PARTICLES IN ISOLATED RAT HEARTS BY REDUCING OXIDATIVE STRESS.

IntroductionEpidemiological studies suggest an association between air pollution and ventricular arrhythmias, with reactive oxygen species (ROS) playing a crucial role. However, the causal relationship and long-term effects remain uncertain, and the effectiveness of interventions aimed at reducing ROS requires further investigation. AimsTo evaluate the effects of chronic exposure to diesel exhaust particles (DEPs) on ventricular arrhythmogenesis, explore the underlying mechanisms, and assess the potential of cerium oxide nanoparticles (CeO2NP) as a ROS-detoxifying intervention. MethodsSprague-Dawley rats underwent intratracheal instillation of saline without or with DEPs (7.5 g/Kg for 1-3 weeks). Ventricular arrhythmia inducibility was then assessed in isolated hearts using a protocol of programmed electrical stimulation. Cardiac hypertrophy, collagen content, inflammation and oxidative stress were analyzed using histology, Western blot, RT-PCR, and measurement of malondialdehyde content. The potential protective effects of CeO2NP (0.5 mg/Kg/week, i.p.) were also tested. ResultsDEP exposure for 3 weeks increased the incidence and duration of sustained ventricular tachyarrhythmias (VTs), a finding that correlated with a moderate increase in interstitial collagen (from 3.11{+/-}0.12% in controls to 4.80{+/-}0.21% in DEP-exposed rats, p<0.001), and an early upregulation in the expression of collagen and other fibrotic and inflammatory markers. These effects associated with prolonged QRS complex and QTc intervals, and enhanced malondialdehyde content (356.7{+/-}21.2 vs. 455.3{+/-}17.2 mol/g tissue, p=0.0066) after 3 weeks. CeO2NP treatment reduced oxidative stress and myocardial fibrosis, reversed electrocardiographic changes and attenuated DEP-induced pro-arrhythmic effects. ConclusionDEP exposure increases the incidence and duration of sustained VTs, collagen deposition and oxidative stress in rats. Treatment with CeO2NP attenuate these effects, arising as a potential novel strategy to mitigate the deleterious effects of air pollution.

pharmacology and toxicology↗

bioRxiv2024

Temporary cerebral ischaemia impairs thromboxane A2 constriction and induces hypertrophic remodelling in peripheral mesenteric arteries of hypertensive rats: limited reversal despite long-term suberoylanilide hydroxamic acid cerebroprotection

Stroke induces brain injury, especially severe in hypertensive patients, and elevates mortality rates through non-neurological complications. However, the potential effects of a transient ischaemic episode on the peripheral vasculature of hypertensive individuals remain unclear. Here, we investigated whether transient cerebral ischaemia (90 min)/reperfusion (1 or 8 days) induces alterations in mesenteric resistance artery (MRA) properties in adult male spontaneously hypertensive rats (SHR). In addition, we assessed whether the reported cerebroprotective effects of suberoylanilide hydroxamic acid (SAHA; 50 mg/kg; administered intraperitoneally at 1, 4, or 6 h after reperfusion onset) extend long-term and include beneficial effects on MRAs. Functional and structural properties of MRAs were examined at 1- and 8-days post-stroke. Nuclei distribution, collagen content, and oxidative stress were assessed. Ischaemic brain damage was evaluated longitudinally using magnetic resonance imaging. Following stroke, MRAs from SHR exhibited non-reversible impaired contractile responses to the thromboxane A2 receptor agonist U46619. Stroke increased the MRA cross-sectional area, wall thickness, and wall/lumen ratio due to augmented collagen deposition. These changes were partially sustained 8 days later. SAHA did not improve U46619-induced contractions but mitigated stroke-induced oxidative stress and collagen deposition, preventing MRA remodelling at 24 h of reperfusion. Furthermore, SAHA induced sustained cerebroprotective effects over 8 days, including reduced brain infarct and oedema, and improved neurological scores. However, SAHA had minimal impact on chronic MRA contractile impairments and remodelling. These findings suggest that stroke causes MRA changes in hypertensive subjects. While SAHA treatment offers long-term protection against brain damage, it cannot fully restore MRA alterations.

neuroscience↗