Advantages of nanocarriers for basic research in the field of traumatic brain injury

A major challenge for the efficient treatment of traumatic brain injury is the need for therapeutic molecules to cross the blood-brain barrier to enter and accumulate in brain tissue.To overcome this problem,researchers have begun to focus on nanocarriers and other brain-targeting drug delivery systems.In this review,we summarize the epidemiology,basic pathophysiology,current clinical treatment,the establishment of models,and the evaluation indicators that are commonly used for traumatic brain injury.We also report the current status of traumatic brain injury when treated with nanocarriers such as liposomes and vesicles.Nanocarriers can overcome a variety of key biological barriers,improve drug bioavailability,increase intracellular penetration and retention time,achieve drug enrichment,control drug release,and achieve brain-targeting drug delivery.However,the application of nanocarriers remains in the basic research stage and has yet to be fully translated to the clinic.

Brain-targeted drug delivery assisted by physical techniques and its potential applications in traditional Chinese medicine

The blood-brain barrier(BBB)constitutes a major obstacle to effective delivery of drugs to the brain.Recent technological advances have led to improvements in brain-targeted drug delivery.In this review,we summarize existing technologies for efficient drug delivery across the BBB.We discuss the mechanisms of current BBB-based drug delivery strategies and introduce prospects for application in braint-argeted delivery of traditional Chinese medicine.We highlight the use of physical techniques for brain-targeted drug delivery,including electroporation,ultrasound,magnetophoresis,microneedles,microwaves,and laser.The characteristics of these techniques and relevant studies employing these approaches are discussed.In general,microneedles,lasers,ultrasound,electroporation,magnetophoresis,and microwaves are effective for drug delivery across the BBB.Notably,the synergistic effects of multiple approaches are superior to the additive effects of each technique in isolation.Our review provides guidance for the practical application of brain-targeted drug delivery techniques in an efficient and safe manner.

Molecular neuro-oncology and development of targeted therapeutic strategies for brain tumors

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches.Molecular neuro-oncologyhas now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targetedtherapy.Activity of the phosphoinositide 3;kinase(PI3K)/Akt pathway is often upregulated in brain tumors due to excessive stimu-lation by growth factor receptors and Ras.Loss of function of the tumor suppressor gene PTEN also frequently contributesto

Brain delivering RNA-based therapeutic strategies by targeting mTOR pathway for axon regeneration after central nervous system injury

Injuries to the central nervous system(CNS)such as stroke,brain,and spinal cord trauma often result in permanent disabilities because adult CNS neurons only exhibit limited axon regeneration.The brain has a surprising intrinsic capability of recovering itself after injury.However,the hostile extrinsic microenvironment significantly hinders axon regeneration.Recent advances have indicated that the inactivation of intrinsic regenerative pathways plays a pivotal role in the failure of most adult CNS neuronal regeneration.Particularly,substantial evidence has convincingly demonstrated that the mechanistic target of rapamycin(mTOR)signaling is one of the most crucial intrinsic regenerative pathways that drive axonal regeneration and sprouting in various CNS injuries.In this review,we will discuss the recent findings and highlight the critical roles of mTOR pathway in axon regeneration in different types of CNS injury.Importantly,we will demonstrate that the reactivation of this regenerative pathway can be achieved by blocking the key mTOR signaling components such as phosphatase and tensin homolog(PTEN).Given that multiple mTOR signaling components are endogenous inhibitory factors of this pathway,we will discuss the promising potential of RNA-based therapeutics which are particularly suitable for this purpose,and the fact that they have attracted substantial attention recently after the success of coronavirus disease 2019 vaccination.To specifically tackle the blood-brain barrier issue,we will review the current technology to deliver these RNA therapeutics into the brain with a focus on nanoparticle technology.We will propose the clinical application of these RNA-mediated therapies in combination with the brain-targeted drug delivery approach against mTOR signaling components as an effective and feasible therapeutic strategy aiming to enhance axonal regeneration for functional recovery after CNS injury.

Effect of borneol and electroacupuncture on the distribution of hyperforin in the rat brain

Hyperforin is an antidepressant drug that has unstable therapeutic effects, due to its poor ability to cross the blood-brain barrier. Borneol and electroacupuncture have both been found to increase the permeability of the blood-brain barrier. As such, the current study examined the distribution of hyperforin in the rat brain, and the effects on the brain distribution of hyperforin of borneol alone （orally administered）, and borneol combined with electroacupuncture treatment. High-performance liquid chromatography technology and pharmacokinetic analysis revealed that treatment with borneol alone （300, 600 mg/kg） increased peak concentration and the area under the curve for hyperforin in the brain. In addition, the bioavailability of hyperforin in rat brain increased by 42.7%. However, increasing the dose of borneol dose did not appear to increase the distribution of hyperforin in the brain. Importantly, applying electroacupuncture at Baihui （GV 20） or Yamen （GV 15） appeared to enhance the brain-delivery effects of borneol, although this effect was weak. Overall, our results indicated that borneol alone or combined with electroacupuncture can provide promising strategies for brain-targeted delivery in central nervous system therapy.

Intranasal delivery of paeoniflorin nanocrystals for brain targeting

Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suitable for intranasal administration to treat Parkinson’s disease(PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of-23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%,which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells.Moreover, PA-NCs conferred desirable protective effect against MPP+-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PANCs is a promising treatment strategy for PD.

Development and evaluation of vinpocetine inclusion complex for brain targeting

The objective of this paper is to prepare vinpocetine(VIN)inclusion complex and evaluate its brain targeting effect after intranasal administration.In the present study,VIN inclusion complex was prepared in order to increase its solubility.Stability constant(Kc)was used for host selection.Factors influencing properties of the inclusion complex was investigated.Formation of the inclusion complex was identified by solubility study and DSC analysis.The brain targeting effect of the complex after intranasal administration was studied in rats.It was demonstrated that properties of the inclusion complex was mainly influenced by cyclodextrin type,organic acids type,system pH and host/guest molar ratio.Multiple component complexes can be formed by the addition of citric acid,with solubility improved for more than 23 times.Furthermore,In vivo study revealed that after intranasal administration,the absolute bioavailability of vinpocetine inclusion complex was 88%.Compared with intravenous injection,significant brain targeting effect was achieved after intranasal delivery,with brain targeting index 1.67.In conclusion,by intranasal administration of VIN inclusion complex,a fast onset of action and good brain targeting effect can be achieved.Intranasal route is a promising approach for the treatment of CNS diseases.

Exploring the potential to enhance drug distribution in the brain subregion via intranasal delivery of nanoemulsion in combination with borneol as a guider

The number of people with Alzheimer’s disease(AD)is increasing annually,with the nidus mainly concentrated in the cortex and hippocampus.Despite of numerous efforts,effective treatment of AD is still facing great challenges due to the blood brain barrier(BBB)and limited drug distribution in the AD nidus sites.Thus,in this study,using vinpocetine(VIN)as a model drug,the objective is to explore the feasibility of tackling the above bottleneck via intranasal drug delivery in combination with a brain guider,borneol(BOR),using nanoemulsion(NE)as the carrier.First of all,the NE were prepared and characterized.In vivo behavior of the NE after intranasal administration was investigated.Influence of BOR dose,BOR administration route on drug brain targeting behavior was evaluated,and the influence of BOR addition on drug brain subregion distribution was probed.It was demonstrated that all the NE had comparable size and similar retention behavior after intranasal delivery.Compared to intravenous injection,improved brain targeting effect was observed by intranasal route,and drug targeting index(DTI)of the VIN–NE group was 154.1%,with the nose-to-brain direct transport percentage(DTP)35.1%.Especially,remarkably enhanced brain distribution was achieved after BOR addition in the NE,with the extent depending on BOR dose.VIN brain concentration was the highest in the VIN-1-BOR-NE group at BOR dose of 1 mg/kg,with the DTI reaching 596.1%and the DTP increased to 83.1%.BOR could exert better nose to brain delivery when administrated together with the drug via intranasal route.Notably,BOR can remarkably enhance drug distribution in both hippocampus and cortex,the nidus areas of AD.In conclusion,in combination with intranasal delivery and the intrinsic brain guiding effect of BOR,drug distribution not only in the brain but also in the cortex and hippocampus can be enhanced significantly,providing the perquisite for improved therapeutic efficacy of AD.

The kallikrein-kinin system: a promising therapeutic target for traumatic brain injury

Traumatic brain injury （TBI）, which results from an outside force causing mechanical disruption of brain tissue, is potentially life-threatening and therefore a critical public health problem throughout the world. In the USA, approximately 1.7 million individuals per year sustain a TBI, and about 43% of patients hospitalized because of TBI develop long-term physical disability as well as psychological disorders,

Drug-and cell-based therapies for targeting neuroinflammation in traumatic brain injury

TBI pathology： Traumatic brain injury （TBI） is caused by an external force to the head, resulting in trauma to the brain. Approximately 1.7 million Americans suffer from TBI every year. Out of the 1.7 million suffering from TBI, an estimated 52,000 injuries result in death, leaving a mass amount of peo- ple with symptoms that could last a few days, a few years, or their entire life （Faul et al., 2010）. TBI can be classified as mild, moderate and severe. Depending on the classification and the extent of the injury, TBI can cause both physical symptoms and cognitive disorders （Lozano et al., 2015）.

Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

Brain-derived neurotrophic factor（BDNF） plays an important role in the repair of central nervous system injury,but cannot directly traverse the blood-brain barrier.Liposomes are a new type of non-viral vector,able to carry macromolecules across the blood-brain barrier and into the brain.Here,we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin（Tf） and polyethylene glycol（PEG）,and carrying BDNF modified with cytomegalovirus promoter（pC MV） or glial fibrillary acidic protein promoter（p GFAP）（Tf-p CMV-BDNF-PEG and Tf-p GFAP-BDNF-PEG,respectively）.Both liposomes were able to traverse the blood-brain barrier,and BDNF was mainly expressed in the cerebral cortex.BDNF expression in the cerebral cortex was higher in the Tf-p GFAP-BDNF-PEG group than in the Tf-p CMV-BDNF-PEG group.This study demonstrates the successful construction of a non-virus targeted liposome,Tf-p GFAP-BDNF-PEG,which crosses the blood-brain barrier and is distributed in the cerebral cortex.Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain.

Combined treatment promotes the long-range axon regeneration to right brain targets

Axons in the peripheral nervous system(PNS)can regenerate after injury.However,the adult mammalian central nervous system(CNS)loses the intrinsic regrowth ability.No robust axon regeneration occurs spontaneously after nerve injury,which was clearly observed by Ramon y Cajal in the early 20^(th) century(1,2).Due to lack

Targeting the body to protect the brain:inducing neuroprotection with remotely-applied near infrared light

The incidence of intractable age-related neurodegenerative conditions such as Alzheimer＇s and Parkinson＇s diseases and age-related macular degeneration is projected to increase substantially over the coming decades with the ageing of the global population. While the burden of disease associ- ated with other chronic conditions has decreased in recent times due to improved diagnosis and treatment, current therapies for neurodegenerative diseases still fall short in that they are only effective in treating signs and symptoms - they do little to slow or prevent disease progress. Thus, there is an urgent need for treatments that address disease progression.

THE USE OF ANTI-HUMAN GLIOMA MONOCLONAL ANTIBODIES FOR TARGETING CHEMOTHERAPY OF BRAIN GLIOMAS(PREPARATION AND CYTOTOXIC PROPERTIES OF ANTIBODY-ADRIAMYCIN IMMUNOCONJUGATES)

Immunoconjugates are antibody-drug hybrid molecules which combine the exquisite selectivity or monoclonal antibodies with the potent toxicity of anticancer agents. A monoclonal antibody SZ39 against human brain gliomas was used as a drug carrier. Adriamycin (ADR) was bound covalently to SZ39 to form a SZ39-ADR conjugate. The cytotoxic activity of the SZ39-ADR conjugate was tested in vitro and demonstrated potent and specific killing of cells derived from a human malignant glioma. 50% inhibitory concentration (IC50) for SZ39-ADR to 'target' cells was 8.14×10-9 M. An index of specificity between 'target' and 'non-target' cells was calculated to be 88-fold. These data suggest that the SZ39-ADR may use as a potent and cell type-specific agent and is a likely candidate for the targeting chemotherapy of malignant gliotnas.

THE USE OF ANTIHUMAN GLIOMA MONOCLONAL ANTIBODIES FOR TARGETING CHEMOTHERAPY OF BRAIN GLIOMAS(POTENT SUPPRESSION OF MALIGNANT GLIOMA GROWTH WITH IMMUNOCONJUGATES IN VIVO)

Athymic nude mice bearing subcutaneous and intracerebral human glioma xenografts were used to assess the therapeutic efficacy of monoclonal anti-body-adriamycin immunoconjugates against malignant gliomas in vivo. Immunoconjugates showed a significantly stronger antitumor effect with a T/C (treated/ control tumor volume) of 30% as compared with free drug (T/C of 84%). The targeting treatment with immunoconjugates significantly prolonged 54% of median survival time of nude mice. Side effects of immunoconjugates on the normal bone marrow and small intestines were much slighter than those of the free drug. The results of this study indicate that the use of monoclonal antibodies as carriers of anti-tumor agents may have many therapeutic advantages and potential for the treatment of brain gliomas.

Bone morphogenetic protein signaling：a promising target for white matter protection in perinatal brain injury

Prematurely born newborns,as well as those born at term,may suffer from several types of brain injury including hypoxic-ischemic injury,intracranial hemorrhage,both intraventricular and parenchymal,and injury that is the consequence of intrauterine growth restriction（IUGR）.Injury of all types can impact the motor and cognitive abilities of survivors.The mechanisms leading to disability are not completely understood.

Lactoferrin modification of berberine nanoliposomes enhances the neuroprotective effects in a mouse model of Alzheimer’s disease

Previous studies have shown that berberine has neuroprotective effects against Alzheimer’s disease,including antagonizing tau phosphorylation,and inhibiting acetylcholinesterase activity and neural cell apoptosis.However,its low bioavailability and adverse reactions with conventional administration limit its clinical application.In this study,we prepared berberine nanoliposomes using liposomes characterized by low toxicity,high entrapment efficiency,and biodegradability,and modified them with lactoferrin.Lactoferrin-modified berberine nanoliposomes had uniform particle size and high entrapment efficiency.We used the lactoferrin-modified berberine nanoliposomes to treat a mouse model of Alzheimer’s disease established by injection of amyloid-beta 1-42 into the lateral ventricle.Lactoferrin-modified berberine nanoliposomes inhibited acetylcholinesterase activity and apoptosis in the hippocampus,reduced tau over-phosphorylation in the cerebral cortex,and improved mouse behavior.These findings suggest that modification with lactoferrin can enhance the neuroprotective effects of berberine nanoliposomes in Alzheimer’s disease.

Selective ischemic-hemisphere targeting Ginkgolide B liposomes with improved solubility and therapeutic efficacy for cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury(CI/RI)remains the main cause of disability and death in stroke patients due to lack of effective therapeutic strategies.One of the main issues related to CI/RI treatment is the presence of the blood-brain barrier(BBB),which affects the intracerebral delivery of drugs.Ginkgolide B(GB),a major bioactive component in commercially available products of Ginkgo biloba,has been shown significance in CI/RI treatment by regulating inflammatory pathways,oxidative damage,and metabolic disturbance,and seems to be a candidate for stroke recovery.However,limited by its poor hydrophilicity and lipophilicity,the development of GB preparations with good solubility,stability,and the ability to cross the BBB remains a challenge.Herein,we propose a combinatorial strategy by conjugating GB with highly lipophilic docosahexaenoic acid(DHA)to obtain a covalent complex GB-DHA,which can not only enhance the pharmacological effect of GB,but can also be encapsulated in liposomes stably.The amount of finally constructed Lipo@GB-DHA targeting to ischemic hemisphere was validated 2.2 times that of free solution in middle cerebral artery occlusion(MCAO)rats.Compared to the marketed ginkgolide injection,Lipo@GB-DHA significantly reduced infarct volume with better neurobehavioral recovery in MCAO rats after being intravenously administered both at 2 h and 6 h post-reperfusion.Low levels of reactive oxygen species(ROS)and high neuron survival in vitro was maintained via Lipo@GB-DHA treatment,while microglia in the ischemic brain were polarized from the pro-inflammatory M1 phenotype to the tissue-repairing M2 phenotype,which modulate neuroinflammatory and angiogenesis.In addition,Lipo@GB-DHA inhibited neuronal apoptosis via regulating the apoptotic pathway and maintained homeostasis by activating the autophagy pathway.Thus,transforming GB into a lipophilic complex and loading it into liposomes provides a promising nanomedicine strategy with excellent CI/RI therapeutic efficacy and industrialization prospects.

The use of localized proteomics to identify the drivers of Alzheimer's disease pathogenesis

Alzheimer’s disease（AD）is broadly defined by dementia and the presence of specific neuropathological features in the brain（amyloid plaques,neurofibrillary tangles（NFTs）and congophilic amyloid angiopathy）.However,the rate of disease progression,type of cognitive impairment,and extent of neuropathology vary widely in patients with AD（Murray et al.,2011）.

Neuroprotective effect of Angiopep-2 peptide modified scutellarin-loaded PEGylated PAMAM dendrimer nanoparticles on ischemic stroke by modulating the Toll-like receptors-dependent MyD88/IKK/NF-κB signaling pathway

OBJECTIVE The greatest challenge in chemotherapy of ischemic stroke is the construction a suitable delivery system to overcome the poor physicochemical properties of drug and its low permeability across the blood brain barrier(BBB).METHODS In the present study,dendrimer,polyamidoamine(PAMAM),was synthesized as the nano-drug carriers.Angiopep-2,which has been proved excellent ability to cross the BBB,was exploited as the targeting ligand to conjugate PAMAM via bifunctional polyethylene glycol(PEG).Then scutellarin(STA)was encapsulated into the functionalized nanoparticles(NPs)to formulate Angiopep-2 modified STA-loaded PEG-PAMAM NPs.Ischemic stroke model was established to evaluate the treatment efficacy and protective mechanism of Angiopep-2-STA-PEG-PAMAM NPs.RESULTS The pharmacokinetics and biodistribu-tion demonstrated that Angiopep-2-STA-PEG-PAMAM NPs exhibited significantly higher plasma concentration from 1 h to 10 h after intravenous administration and improve accumulation in brain(4.7-fold)compared with STA solution.Moreover,prolonged elimination half-life(4.8-fold)and lower clearance(3.4-fold)were observed.The brain uptake study of 6-coumarin confirmed that Angiopep-2-PEG-PAMAM NPs possessed better brain targeting efficacy(3.2-fold)than PEG-PAMAM NPs.Angiopep-2-STA-PEG-PAMAM NPs obviously ameliorated infarct volume,neurological deficit,histopathological severity and neuronal apoptosis.In addition,Angiopep-2-STA-PEG-PAMAM NPs markedly inhibited the calcium content and the levels of IL-12p40,IL-13,IL-17 and IL-23.Furthermore,Angiopep-2-STA-PEG-PAMAM NPs significantly decreased the m RNA and protein expressions of HMGB1,TLR2,TLR4,TLR5,My D88,TRIF,TRAM,IRAK-4,TRAF6,IкBα,IKKβand NF-кBp65.CONCLUSION The results suggested that Angiopep-2modified scutellarin-loaded PEG-PAMAM nanocarriers possessed remarkable neuroprotective effects on ischemic stroke through modulation of inflammatory cascades and HMGB1/TLRs/MyD 88-induced NF-κB activation pathways.