Mild TBI Changes Brain and Plasma Neurosteroid Levels in Mice.

Mild traumatic brain injury (mTBI) accounts for 80% of all TBI, may be associated with chronic impairments, and is difficult to diagnose due to a lack of objective markers. In this study, we investigated whether neurosteroids can serve as blood biomarkers for mTBI. Two cohorts of C57BL/6 mice were subjected to a model of mTBI combining impact with rotational acceleration or sham surgery.

P2X7R antagonism suppresses long-lasting brain hyperexcitability following traumatic brain injury in mice.

Post-traumatic epilepsy (PTE) is one of the most common life-quality reducing consequences of traumatic brain injury (TBI). However, to date there are no pharmacological approaches to predict or to prevent the development of PTE. The P2X7 receptor (P2X7R) is a cationic ATP-dependent membrane channel that is expressed throughout the brain.

Nanocarrier imaging at single-cell resolution across entire mouse bodies with deep learning.

Efficient and accurate nanocarrier development for targeted drug delivery is hindered by a lack of methods to analyze its cell-level biodistribution across whole organisms. Here we present Single Cell Precision Nanocarrier Identification (SCP-Nano), an integrated experimental and deep learning pipeline to comprehensively quantify the targeting of nanocarriers throughout the whole mouse body at single-cell resolution. SCP-Nano reveals the tissue distribution patterns of lipid nanoparticles (LNPs) after different injection routes at doses as low as 0.

Reliable infarction of the middle cerebral artery territory in C57BL/6 mice using pterygopalatine artery ligation and filament optimization - The PURE-MCAo model.

Current techniques for inducing intraluminal filamentous middle cerebral artery occlusion (fMCAo) in mice produce highly variable results and often cause additional infarcts in the posterior cerebral artery (PCA) territory. The aim of the current study was to develop a novel procedure to overcome these shortcomings. Male C57BL/6 mice were subjected to 60 min of fMCAo with cerebral blood flow monitored by laser Doppler flowmetry.

Combining array tomography with electron tomography provides insights into leakiness of the blood-brain barrier in mouse cortex.

Like other volume electron microscopy approaches, automated tape-collecting ultramicrotomy (ATUM) enables imaging of serial sections deposited on thick plastic tapes by scanning electron microscopy (SEM). ATUM is unique in enabling hierarchical imaging and thus efficient screening for target structures, as needed for correlative light and electron microscopy. However, SEM of sections on tape can only access the section surface, thereby limiting the axial resolution to the typical size of cellular vesicles with an order of magnitude lower than the acquired xy resolution.

Bradykinin 2 Receptors Mediate Long-Term Neurocognitive Deficits After Experimental Traumatic Brain Injury.

The kallikrein-kinin system is one of the first inflammatory pathways to be activated following traumatic brain injury (TBI) and has been shown to exacerbate brain edema formation in the acute phase through activation of bradykinin 2 receptors (B2R). However, the influence of B2R on chronic post-traumatic damage and outcome is unclear. In the current study, we assessed long-term effects of B2R-knockout (KO) after experimental TBI.

To see or not to see: In vivo nanocarrier detection methods in the brain and their challenges.

Nanoparticles have a great potential to significantly improve the delivery of therapeutics to the brain and may also be equipped with properties to investigate brain function. The brain, being a highly complex organ shielded by selective barriers, requires its own specialized detection system. However, a significant hurdle to achieve these goals is still the identification of individual nanoparticles within the brain with sufficient cellular, subcellular, and temporal resolution.

Continued dysfunction of capillary pericytes promotes no-reflow after experimental stroke in vivo.

Incomplete reperfusion of the microvasculature ('no-reflow') after ischaemic stroke damages salvageable brain tissue. Previous ex vivo studies suggest pericytes are vulnerable to ischaemia and may exacerbate no-reflow, but the viability of pericytes and their association with no-reflow remains under-explored in vivo. Using longitudinal in vivo two-photon single-cell imaging over 7 days, we showed that 87% of pericytes constrict during cerebral ischaemia and remain constricted post reperfusion, and 50% of the pericyte population are acutely damaged.

Perivascular Macrophages Mediate Microvasospasms After Experimental Subarachnoid Hemorrhage.

Background: Subarachnoid hemorrhage (SAH) is characterized by acute and delayed reductions of cerebral blood flow (CBF) caused, among others, by spasms of cerebral arteries and arterioles. Recently, the inactivation of perivascular macrophages (PVM) has been demonstrated to improve neurological outcomes after experimental SAH, but the underlying mechanisms of protection remain unclear. The aim of our exploratory study was, therefore, to investigate the role of PVM in the formation of acute microvasospasms after experimental SAH.

Size-Selective Transfer of Lipid Nanoparticle-Based Drug Carriers Across the Blood Brain Barrier Via Vascular Occlusions Following Traumatic Brain Injury.

The current lack of understanding about how nanocarriers cross the blood-brain barrier (BBB) in the healthy and injured brain is hindering the clinical translation of nanoscale brain-targeted drug-delivery systems. Here, the bio-distribution of lipid nano-emulsion droplets (LNDs) of two sizes (30 and 80 nm) in the mouse brain after traumatic brain injury (TBI) is investigated. The highly fluorescent LNDs are prepared by loading them with octadecyl rhodamine B and a bulky hydrophobic counter-ion, tetraphenylborate.

Dynamic tracing using ultra-bright labeling and multi-photon microscopy identifies endothelial uptake of poloxamer 188 coated poly(lactic-co-glycolic acid) nano-carriers in vivo.

The potential of poly(lactic-co-glycolic acid) (PLGA) to design nanoparticles (NPs) and target the central nervous system remains to be exploited. In the current study we designed fluorescent 70-nm PLGA NPs, loaded with bulky fluorophores, thereby making them significantly brighter than quantum dots in single-particle fluorescence measurements. The high brightness of NPs enabled their visualization by intravital real-time 2-photon microscopy.

RIPK1 or RIPK3 deletion prevents progressive neuronal cell death and improves memory function after traumatic brain injury.

Traumatic brain injury (TBI) causes acute and subacute tissue damage, but is also associated with chronic inflammation and progressive loss of brain tissue months and years after the initial event. The trigger and the subsequent molecular mechanisms causing chronic brain injury after TBI are not well understood. The aim of the current study was therefore to investigate the hypothesis that necroptosis, a form a programmed cell death mediated by the interaction of Receptor Interacting Protein Kinases (RIPK) 1 and 3, is involved in this process.

Ultrabright Fluorescent Polymeric Nanoparticles with a Stealth Pluronic Shell for Live Tracking in the Mouse Brain.

Visualizing single organic nanoparticles (NPs) remains a challenge, which could greatly improve our understanding of the bottlenecks in the field of nanomedicine. To achieve high single-particle fluorescence brightness, we loaded polymer poly(methyl methacrylate)-sulfonate (PMMA-SOH) NPs with octadecyl rhodamine B together with a bulky hydrophobic counterion (perfluorinated tetraphenylborate) as a fluorophore insulator to prevent aggregation-caused quenching. To create NPs with stealth properties, we used the amphiphilic block copolymers pluronic F-127 and F-68.

Brain-derived neurotrophic factor delivered to the brain using poly (lactide-co-glycolide) nanoparticles improves neurological and cognitive outcome in mice with traumatic brain injury.

Currently, traumatic brain injury (TBI) is the leading cause of death or disabilities in young individuals worldwide. The multi-complexity of its pathogenesis as well as impermeability of the blood-brain barrier (BBB) makes the drug choice and delivery very challenging. The brain-derived neurotrophic factor (BDNF) regulates neuronal plasticity, neuronal cell growth, proliferation, cell survival and long-term memory.

A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency.

Traumatic brain injury (TBI) is a leading cause of death and disability in individuals worldwide. Producing a clinically relevant TBI model in small-sized animals remains fairly challenging. For good screening of potential therapeutics, which are effective in the treatment of TBI, animal models of TBI should be established and standardized.

Targeted delivery of brain-derived neurotrophic factor for the treatment of blindness and deafness.

Neurodegenerative causes of blindness and deafness possess a major challenge in their clinical management as proper treatment guidelines have not yet been found. Brain-derived neurotrophic factor (BDNF) has been established as a promising therapy against neurodegenerative disorders including hearing and visual loss. Unfortunately, the blood-retinal barrier and blood-cochlear barrier, which have a comparable structure to the blood-brain barrier prevent molecules of larger sizes (such as BDNF) from exiting the circulation and reaching the targeted cells.

Nanoscale drug delivery systems and the blood-brain barrier.

The protective properties of the blood-brain barrier (BBB) are conferred by the intricate architecture of its endothelium coupled with multiple specific transport systems expressed on the surface of endothelial cells (ECs) in the brain's vasculature. When the stringent control of the BBB is disrupted, such as following EC damage, substances that are safe for peripheral tissues but toxic to neurons have easier access to the central nervous system (CNS). As a consequence, CNS disorders, including degenerative diseases, can occur independently of an individual's age.

Arginine glutamate improves healing of radiation-induced skin ulcers in guinea pigs.

Purpose: The increase in the incidence of the radiation-induced skin injury cases and the absence of standard treatments escalate the interest in finding new and effective drugs for these lesions. We studied the effect of a 40% solution of arginine glutamate on the healing of radiation-induced skin ulcers in guinea pigs.

Materials And Methods: Radiation skin injury was produced on the thigh of guinea pigs by 60 Gy local X-ray irradiation.