Propranolol is the first-line drug for managing migraine attacks. D-limonene is a citrus oil known for its neuroprotective mechanism. Thus, the current work aims to design a thermo-responsive intranasal limonene-based microemulsion mucoadhesive nanogel to improve propranolol efficacy. Microemulsion was fabricated using limonene and Gelucire^® as the oily phase, Labrasol^®, Labrafil^®, and deionized water as the aqueous phase, and was characterized regarding its physicochemical features. The microemulsion was loaded in thermo-responsive nanogel and evaluated regarding its physical and chemical properties, in vitro release, and ex vivo permeability through sheep nasal tissues. Its safety profile was assessed via histopathological examination, and its capability to deliver propranolol effectively to rats’ brains was examined using brain biodistribution analysis. Limonene-based microemulsion was of 133.7 ± 0.513 nm diametric size with unimodal size distribution and spheroidal shape. The nanogel showed ideal characteristics with good mucoadhesive properties and in vitro controlled release with 1.43-fold enhancement in ex vivo nasal permeability compared with the control gel. Furthermore, it displayed a safe profile as elucidated by the nasal histopathological features. The nanogel was able to improve propranolol brain availability with C_max 970.3 ± 43.94 ng/g significantly higher than the control group (277.7 ± 29.71 ng/g) and with 382.4 % relative central availability, which confirms its potential for migraine management.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelination and axonal damage. Current therapies primarily manage symptoms and slow disease progression but do not achieve remyelination. This systematic review evaluates the efficacy and safety of remyelination-promoting interventions in MS, focusing on clinical trials utilizing outcome measures validated in prior studies as indicators of remyelination. A comprehensive search of PubMed, Embase, Web of Science, and Cochrane Library was conducted in May 2024. Clinical trials assessing interventions with potential remyelinating properties were included. Data extraction followed standardized forms, and study quality was evaluated using ROBINS-I for non-randomized trials and RoB 2.0 for RCTs. Remyelination was assessed using Magnetization Transfer Ratio (MTR), Visual Evoked Potentials (VEPs), Myelin Water Fraction (MWF), Diffusion Tensor Imaging (DTI), and Optical Coherence Tomography (OCT). From 1,615 screened records, 25 studies met the inclusion criteria and were analyzed. Across the 3341 participants, 17 interventions were evaluated. Most studies demonstrated a moderate risk of bias, yet all interventions, except one, were generally safe and well tolerated. Notably, rHIgM22, L-T3, opicinumab, clemastine fumarate, phenonytoin, domperidone, GSK239512, human fetal neural precursor cells (hfNPCs), and low-intensity repetitive transcranial magnetic stimulation (LI-rTMS) exhibited remyelination potential. Additionally, disease-modifying therapies (DMTs) such as Ocrelizumab, Fingolimod, and Natalizumab showed promising effects. Although several interventions demonstrated remyelination potential, limitations such as small sample sizes, short follow-up periods, and lack of standardized clinical endpoints validating remyelination's functional impact, highlight the need for robust clinical trial designs, advanced biomarkers, and combination therapies integrating remyelination, neuroprotection, and immunomodulation to improve MS treatment outcomes.

COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), is clinically defined by persistent symptoms that endure beyond acute infection and affect multiple organ systems, including the immune, cardiopulmonary, neurological, and metabolic axes. The underlying mechanisms remain poorly resolved, limiting the development of targeted diagnostics and therapeutics. MicroRNAs (miRNAs), as key post-transcriptional regulators of gene expression, control inflammatory networks, antiviral responses, mitochondrial bioenergetics, and fibrotic pathways, all of which are implicated in long COVID pathogenesis. Recent studies show durable changes in circulating miRNA signatures months after recovery from the acute phase, suggesting a role in maintaining chronic immune activation and metabolic dysfunction. Importantly, circulating miRNAs are stable, quantifiable in biofluids, and reflect systems-level dysregulation, positioning them as promising biomarker candidates for patient stratification, symptom clustering, and disease monitoring. Moreover, miRNA-directed interventions, such as mimics and antagomiRs, represent an emerging precision-medicine strategy to correct sustained molecular disturbances. This review summarizes current evidence linking miRNAs to long COVID, highlights their biomarker potential, and discusses therapeutic avenues that may help advance mechanism-based interventions for this globally emerging chronic condition.