Objectives: Eplerenone (EPL), an antagonist of the mineralocorticoid receptor, is beneficial for atrial fibrillation and atrial fibrosis. However, the underlying mechanism remains less well known. We aimed to investigate the effect of EPL on atrial fibrosis using a mouse with selective atrial fibrosis and to explore the underlying mechanisms. Methods: EPL-treated MHC-TGFcys³³ser transgenic mice that have selective atrial fibrosis (Tx+EPL mice), as well as control mice, were used for in vivo studies including histological analyses, Western blotting, and qRT-PCR studies. TGF-β₁-stimulated atrial fibroblasts were treated with EPL or vehicle for the in vitro studies including Western blotting and qRT-PCR studies. In addition, Smad7 siRNA was used to knock down Smad7. Results: EPL inhibited atrial fibrosis in the Tx mice. In addition, EPL suppressed the expression of fibrosis-related molecules induced by TGF-β₁ in vivo and in vitro. This occurred in concert with a downregulation of Smad7 protein expression and an upregulation of p-Smad2/3 protein expression. In addition, knockdown of Smad7 by siRNA abolished the protective roles of EPL. Conclusions: EPL inhibited atrial fibrosis in Tx mice. The underlying mechanism may involve increased protein expression of Smad7, which enhances the inhibitory feedback regulation of TGF-β₁/Smad signaling.

Aims: MicroRNAs (miRs) are involved in endogenous neurogenesis, enhancing of which has been regarded as a potential therapeutic strategy for ischemic stroke treatment; however, whether miR‐199a‐5p mediates postischemic neurogenesis remains unclear. This study aims to investigate the proneurogenesis effects of miR‐199a‐5p and its possible mechanism after ischemic stroke.Methods: Neural stem cells (NSCs) were transfected using Lipofectamine 3000 reagent, and the differentiation of NSCs was evaluated by immunofluorescence and Western blotting. Dual‐luciferase reporter assay was performed to verify the target gene of miR‐199a‐5p. MiR‐199a‐5p agomir/antagomir were injected intracerebroventricularly. The sensorimotor functions were evaluated by neurobehavioral tests, infarct volume was measured by toluidine blue staining, neurogenesis was detected by immunofluorescence assay, and the protein levels of neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), caveolin‐1 (Cav‐1), vascular endothelial growth factor (VEGF), and brain‐derived neurotrophic factor (BDNF) were measured by Western blotting.Results: MiR‐199a‐5p mimic enhanced neuronal differentiation and inhibited astrocyte differentiation of NSCs, while a miR‐199a‐5p inhibitor induced the opposite effects, which can be reversed by Cav‐1 siRNA. Cav‐1 was through the dual‐luciferase reporter assay confirmed as a target gene of miR‐199a‐5p. miR‐199a‐5p agomir in rat stroke models manifested multiple benefits, such as improving neurological deficits, reducing infarct volume, promoting neurogenesis, inhibiting Cav‐1, and increasing VEGF and BDNF, which was reversed by the miR‐199a‐5p antagomir.Conclusion: MiR‐199a‐5p may target and inhibit Cav‐1 to enhance neurogenesis and thus promote functional recovery after cerebral ischemia. These findings indicate that miR‐199a‐5p is a promising target for the treatment of ischemic stroke.

The neurovascular unit (NVU) is composed of a diverse array of cells and an extracellular matrix (ECM). Neural cells and blood vessels are intricately interconnected, forming a cohesive whole. Specific cellular components and structures within the NVU play an indispensable role in maintaining homeostasis of the central nervous system (CNS). With the advancement and maturation of cell co-culture technology, various three-dimensional (3D) NVU models continue to emerge, offering a more objective and comprehensive perspective for in vitro studies of CNS diseases. Specifically, these 3D NVU models include Transwell Chamber models, gel-polydimethylsiloxane (PDMS)-based 3D models, self-assembled NVU models and microfluidic NVU models, which reconstruct the complex NVU architecture to varying degrees. This review systematically summarizes multiple 3D construction strategies for in vitro NVU to overcome the limitations of conventional cellular tests or animal experiments, highlights the critical roles of biomimetic gel in recapitulating native cell-gel crosstalk, comparatively analyzes four major 3D NVU technical routes in terms of cellular composition, vascular morphology, barrier performance, and reproducibility, categorizes application scenarios of 3D NVU platforms oriented to practical research demands, including oxygen-glucose deprivation/reoxygenation (OGD/R) injury modeling, blood-brain barrier (BBB) permeability assay, CNS drug penetration screening, neuroinflammation and neurotoxicity evaluation, proposes practical principles for model selection under different experimental purposes, and concludes with current bottlenecks, including imperfect vascular network maturation and lack of unified evaluation criteria, together with future perspectives for standardized 3D NVU in vitro. By comparing the advantages and limitations of these approaches, we aim to clarify their optimal applicability for investigating specific pathological mechanisms and screening potential therapeutics.

Rationale: Refractory hypotension may aggravate cerebral hypoperfusion in acute ischemic stroke, but occult coronary artery disease is often overlooked. Patient concerns: A 67-year-old man presented with sudden right-sided weakness. Within 24 hours, he developed persistent hypotension (approximately 90–100/50–60 mm Hg) and neurological worsening. Diagnoses: Brain magnetic resonance imaging revealed an acute left frontoparietal watershed infarction. Despite fluid resuscitation and vasopressors, hemodynamic instability persisted. Hypovolemia, endocrine disorders, and cervico-cephalic stenosis were excluded. Although cardiac biomarkers and ejection fraction were normal, electrocardiography showed inferior Q waves. Coronary angiography confirmed critical left anterior descending (LAD) artery stenosis with distal occlusion. Interventions: Fluid resuscitation and vasopressor support failed to stabilize blood pressure. Balloon angioplasty was performed for the left anterior descending artery lesion. Outcomes: After intervention, blood pressure normalized without vasopressors, and neurological function improved. Lessons: In acute ischemic stroke patients with unexplained refractory hypotension and watershed infarction, occult coronary ischemia should be considered even when troponin is normal. Early coronary evaluation and timely revascularization may improve cerebral perfusion and outcomes.