Intranasal Administration of chitosan-Coated Nanostructured Lipid Carriers Loaded with GDNF Improves Behavioral and Histological Recovery in a Partial Lesion Model of Parkinson's Disease

Cryogel microcarriers for sustained local delivery of growth factors to the brain

Neurotrophic growth factors such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) have been considered as potential therapeutic candidates for neurodegenerative disorders due to their important role in modulating the growth and survival of neurons. However, clinical translation remains elusive, as their large size hinders translocation across the blood-brain barrier (BBB), and their short half-life in vivo necessitates repeated administrations. Local delivery to the brain offers a potential route to the target site but requires a suitable drug-delivery system capable of releasing these proteins in a controlled and sustained manner. Herein, we develop a cryogel microcarrier delivery system which takes advantage of the heparin-binding properties of GDNF and BDNF, to reversibly bind/release these growth factors via electrostatic interactions. Droplet microfluidics and subzero temperature polymerization was used to create monodisperse cryogels with varying degrees of negative charge and an average diameter of 20 μm. By tailoring the inclusion of 3-sulfopropyl acrylate (SPA) as a negatively charged moiety, the release duration of these two growth factors could be adjusted to range from weeks to half a year. 80% SPA cryogels and 20% SPA cryogels were selected to load GDNF and BDNF respectively, for the subsequent biological studies. Cell culture studies demonstrated that these cryogel microcarriers were cytocompatible with neuronal and microglial cell lines, as well as primary neural cultures. Furthermore, in vivo studies confirmed their biocompatibility after administration into the brain, as well as their ability to deliver, retain and release GDNF and BDNF in the striatum. Overall, this study highlights the potential of using cryogel microcarriers for long-term delivery of neurotrophic growth factors to the brain for neurodegenerative disorder therapeutics.

Chitosan-coated nanostructured lipid carriers for effective brain delivery of Tanshinone IIA in Parkinson's disease: interplay between nuclear factor-kappa β and cathepsin B

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder associated with increased oxidative stress, the underlying vital process contributing to cell death. Tanshinone IIA (TAN) is a phytomedicine with a documented activity in treating many CNS disorders, particularly PD owing to its unique anti-inflammatory and antioxidant effect. However, its clinical utility is limited by its poor aqueous solubility, short half-life, and hence low concentration reaching targeted cells. This work aimed to develop a biocompatible chitosan-coated nanostructured lipid carriers (CS-NLCs) for effective brain delivery of TAN for PD management. The proposed nanosystem was successfully prepared using a simple melt-emulsification ultra-sonication method, optimized and characterized both in vitro and in vivo in a rotenone-induced PD rat model. The developed TAN-loaded CS-NLCs (CS-TAN-NLCs) showed good colloidal properties (size ≤ 200 nm, PDI ≤ 0.2, and ζ-potential + 20 mV) and high drug entrapment efficiency (> 97%) with sustained release profile for 24 h. Following intranasal administration, CS-TAN-NLCs succeeded to achieve a remarkable antiparkinsonian and antidepressant effect in diseased animals compared to both the uncoated TAN-NLCs and free TAN suspension as evidenced by the conducted behavioral tests and improved histopathological findings. Furthermore, biochemical evaluation of oxidative stress along with inflammatory markers, nuclear factor-kabba β (NF-Kβ) and cathepsin B further confirmed the potential of the CS-TAN-NLCs in enhancing brain delivery and hence the therapeutic effect of TAN of treatment of PD. Accordingly, CS-TAN-NLCs could be addressed as a promising nano-platform for the effective management of PD.

Nano Lipid Carriers as a Promising Drug Delivery Carrier for Neurodegenerative Disorders - An Overview of Recent Advances

The last few decades have seen a rise in the number of deaths caused by neurological disorders. The blood-brain barrier (BBB), which is very complex and has multiple mechanisms, makes drug delivery to the brain challenging for many scientists. Lipid nanoparticles (LNPs) such as nanoemulsions, solid-lipid nanoparticles, liposomes, and nano lipid carriers (NLCs) exhibit enhanced bioavailability and flexibility among these nanocarriers. NLCs are found to be very effective. In the last few decades, they have been a center of attraction for controlled drug delivery. According to the current global status of specific neurological disorders, out of all LNPs, NLC significantly reduces the cross-permeability of drugs through the BBB due to their peculiar properties. They offer a host of advantages over other carriers because of their biocompatibility, safety, non-toxicity, non-irritating behavior, stability, high encapsulation efficiency, high drug loading, high drug targeting, control of drug release, and ease in manufacturing. The biocompatible lipid matrix is ideally suited as a drug carrier system due to the nano-size range. For certain neurological conditions such as Parkinsonism, Alzheimer's, Epilepsy, Multiple sclerosis, and Brain cancer, we examined recent advances in NLCs to improve brain targeting of bioactive with special attention to formulation aspects and pharmacokinetic characteristics. This article also provides a brief overview of a critical approach for brain targeting, i.e., direct nose-to-brain drug delivery and some recent patents published on NLC".

Nanocarrier Mediated Intranasal Drug Delivery Systems for the Management of Parkinsonism: A Review

The transport of drugs to the brain becomes a key concern when treating disorders of the central nervous system. Parkinsonism is one of the major concerns across the world populations, which causes difficulty in coordination and balance. However, the blood-brain barrier is a significant barrier to achieving optimal brain concentration through oral, transdermal, and intravenous routes of administration. The intranasal route with nanocarrier-based formulations has shown potential for managing Parkinsonism disorder (PD). Direct delivery to the brain through the intranasal route is possible via the olfactory and trigeminal pathways using drug-loaded nanotechnology-based drug delivery systems. The critical analysis of reported works demonstrates dose reduction, brain targeting, safety, effectiveness, and stability for drug-loaded nanocarriers. The important aspects of intranasal drug delivery, PD details, and nanocarrier-based intranasal formulations in PD management with a discussion of physicochemical characteristics, cell line studies, and animal studies are the major topics in this review. Patent reports and clinical investigations are summarized in the last sections.

Nose-to-Brain (N2B) Delivery: An Alternative Route for the Delivery of Biologics in the Management and Treatment of Central Nervous System Disorders

In recent years, there have been a growing number of small and large molecules that could be used to treat diseases of the central nervous system (CNS). Nose-to-brain delivery can be a potential option for the direct transport of molecules from the nasal cavity to different brain areas. This review aims to provide a compilation of current approaches regarding drug delivery to the CNS via the nose, with a focus on biologics. The review also includes a discussion on the key benefits of nasal delivery as a promising alternative route for drug administration and the involved pathways or mechanisms. This article reviews how the application of various auxiliary agents, such as permeation enhancers, mucolytics, in situ gelling/mucoadhesive agents, enzyme inhibitors, and polymeric and lipid-based systems, can promote the delivery of large molecules in the CNS. The article also includes a discussion on the current state of intranasal formulation development and summarizes the biologics currently in clinical trials. It was noted that significant progress has been made in this field, and these are currently being applied to successfully transport large molecules to the CNS via the nose. However, a deep mechanistic understanding of this route, along with the intimate knowledge of various excipients and their interactions with the drug and nasal physiology, is still necessary to bring us one step closer to developing effective formulations for nasal-brain drug delivery.

Targeting the central nervous system: From synthetic nanoparticles to extracellular vesicles-Focus on Alzheimer's and Parkinson's disease

Neurodegenerative diseases (NDs) such as Alzheimer's disease (AD) and Parkinson's disease (PD) are an accelerating global health problem as life expectancy rises worldwide. Despite their significant burden in public health systems to date, the existing treatments only manage the symptoms without slowing down disease progression. Thus, the ongoing neurodegenerative process remains untreated. Moreover, the stronghold of the brain-the blood-brain barrier (BBB)-prevents drug penetrance and dwindles effective treatments. In the last years, nanotechnology-based drug delivery systems (DDS) have become a promising approach to target and treat these disorders related to the central nervous system (CNS). PLGA based nanoparticles (NPs) were the first employed DDS for effective drug delivery. However, the poor drug loading capacity and localized immunogenicity prompted the scientific community to move to another DDS such as lipid-based NPs. Despite the lipid NPs' safety and effectiveness, their off-target accumulation together with the denominated CARPA (complement activation-related pseudo allergy) reaction has limited their complete clinical translation. Recently, biological NPs naturally secreted by cells, termed as extracellular vesicles (EVs) have emerged as promising more complex biocompatible DDS. In addition, EVs act as dual players in NDs treatment, as a "cell free" therapy themselves, as well as new biological NPs with numerous characteristics that qualify them as promising carriers over synthetic DDS. The present review aims to display advantages, drawbacks, current limitations and future prospective of the previously cited synthetic and biological DDS to enter the brain and treat one of 21st century most challenging diseases, NDs. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease.

Efficacy of invasive and non-invasive methods for the treatment of Parkinson's disease: Nanodelivery and enriched environment

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterised by the loss of dopaminergic neurons in the substantia nigra pars compacta and the subsequent motor disability. The most frequently used treatments in clinics, such as L-DOPA, restore dopaminergic neurotransmission in the brain. However, these treatments are only symptomatic, have temporary efficacy, and produce side effects. Part of the side effects are related to the route of administration as the consumption of oral tablets leads to unspecific pulsatile activation of dopaminergic receptors. For this reason, it is necessary to not only find alternative treatments, but also to develop new administration systems with better security profiles. Nanoparticle delivery systems are new administration forms designed to reach the pharmacological target in a highly specific way, leading to better drug bioavailability, efficacy and safety. Some of these delivery systems have shown promising results in animal models of PD not only when dopaminergic drugs are administered, but even more when neurotrophic factors are released. These latter compounds promote maturation and survival of dopaminergic neurons and can be exogenously administered in the form of pharmacological therapy or endogenously generated by non-pharmacological methods. In this sense, experimental exposure to enriched environments, a non-invasive strategy based on the combination of social and inanimate stimuli, enhances the production of neurotrophic factors and produces a neuroprotective effect in parkinsonian animals. In this review, we will discuss new nanodelivery systems in PD with a special focus on therapies that increase the release of neurotrophic factors.

Challenges in the Development and Application of Organ-on-Chips for Intranasal Drug Delivery Studies

With the growing demand for the development of intranasal (IN) products, such as nasal vaccines, which has been especially highlighted during the COVID-19 pandemic, the lack of novel technologies to accurately test the safety and effectiveness of IN products in vitro so that they can be delivered promptly to the market is critically acknowledged. There have been attempts to manufacture anatomically relevant 3D replicas of the human nasal cavity for in vitro IN drug tests, and a couple of organ-on-chip (OoC) models, which mimic some key features of the nasal mucosa, have been proposed. However, these models are still in their infancy, and have not completely recapitulated the critical characteristics of the human nasal mucosa, including its biological interactions with other organs, to provide a reliable platform for preclinical IN drug tests. While the promising potential of OoCs for drug testing and development is being extensively investigated in recent research, the applicability of this technology for IN drug tests has barely been explored. This review aims to highlight the importance of using OoC models for in vitro IN drug tests and their potential applications in IN drug development by covering the background information on the wide usage of IN drugs and their common side effects where some classical examples of each area are pointed out. Specifically, this review focuses on the major challenges of developing advanced OoC technology and discusses the need to mimic the physiological and anatomical features of the nasal cavity and nasal mucosa, the performance of relevant drug safety assays, as well as the fabrication and operational aspects, with the ultimate goal to highlight the much-needed consensus, to converge the effort of the research community in this area of work.

Intranasal Peptide Therapeutics: A Promising Avenue for Overcoming the Challenges of Traditional CNS Drug Development

The central nervous system (CNS) has, among all organ systems in the human body, the highest failure rate of traditional small-molecule drug development, ranging from 80-100% depending on the area of disease research. This has led to widespread abandonment by the pharmaceutical industry of research and development for CNS disorders, despite increased diagnoses of neurodegenerative disorders and the continued lack of adequate treatment options for brain injuries, stroke, neurodevelopmental disorders, and neuropsychiatric illness. However, new approaches, concurrent with the development of sophisticated bioinformatic and genomic tools, are being used to explore peptide-based therapeutics to manipulate endogenous pathways and targets, including "undruggable" intracellular protein-protein interactions (PPIs). The development of peptide-based therapeutics was previously rejected due to systemic off-target effects and poor bioavailability arising from traditional oral and systemic delivery methods. However, targeted nose-to-brain, or intranasal (IN), approaches have begun to emerge that allow CNS-specific delivery of therapeutics via the trigeminal and olfactory nerve pathways, laying the foundation for improved alternatives to systemic drug delivery. Here we review a dozen promising IN peptide therapeutics in preclinical and clinical development for neurodegenerative (Alzheimer's, Parkinson's), neuropsychiatric (depression, PTSD, schizophrenia), and neurodevelopmental disorders (autism), with insulin, NAP (davunetide), IGF-1, PACAP, NPY, oxytocin, and GLP-1 agonists prominent among them.

Protein and Gene Delivery Systems for Neurodegenerative Disorders: Where Do We Stand Today?

It has been estimated that every year, millions of people are affected by neurodegenerative disorders, which complicate their lives and their caregivers' lives. To date, there has not been an approved pharmacological approach to provide the complete treatment of neurodegenerative disorders. The only available drugs may only relieve the symptoms or slow down the progression of the disease. The absence of any treatment is quite rational given that neurodegeneration occurs by the progressive loss of the function or structure of the nerve cells of the brain or the peripheral nervous system, which eventually leads to their death either by apoptosis or necrotic cell death. According to a recent study, even though adult brain cells are injured, they can revert to an embryonic state, which may help to restore their function. These interesting findings might open a new path for the development of more efficient therapeutic strategies to combat devastating neurodegenerative disorders. Gene and protein therapies have emerged as a rapidly growing field for various disorders, especially neurodegenerative diseases. Despite these promising therapies, the complete treatment of neurodegenerative disorders has not yet been achieved. Therefore, the aim of this review is to address the most up-to-date data for neurodegenerative diseases, but most importantly, to summarize the available delivery systems incorporating proteins, peptides, and genes that can potentially target such diseases and pass into the blood-brain barrier. The authors highlight the advancements, at present, on delivery based on the carrier, i.e., lipid, polymeric, and inorganic, as well as the recent studies on radiopharmaceutical theranostics.

Intranasal delivery of biotechnology-based therapeutics

Biotechnology-based therapeutics include a wide range of products, such as recombinant hormones, stem cells, therapeutic enzymes, monoclonal antibodies, genes, vaccines, among others. The administration of these macromolecules has been studied via various routes. The nasal route is one of the promising routes of administration for biotechnology products owing to its easy delivery, the rich vascularity of the nasal mucosa, high absorption and targeted action. Several preclinical studies have been reported for nasal delivery of these products and many are at the clinical stage. This review focuses on biotechnology-based therapeutics administered via the intranasal route for treating various diseases.

Formulation of intranasal surface engineered nanostructured lipid carriers of rotigotine: Full factorial design optimization, in vitro characterization, and pharmacokinetic evaluation

The objective of the present research was to develop, optimize, and evaluate rotigotine (RT)-loaded chitosan (CH) coated nanostructured lipid carriers (RT-CH-NLCs) for nose-to-brain delivery. The NLCs were prepared by homogenization and sonication technique as well as optimized by using three factors at three-level Box-Behnken design. The prepared NLCs were evaluated for particle size, zeta potential, entrapment efficiency, drug release, and ex vivo permeation. The pharmacokinetic study was conducted on albino Wistar rats to evaluate the bioavailability and neuropharmacokinetic parameters after intranasal administration of the optimized formulation (RT-CH-NLCs-OPT). The optimized formulation showed the particle size (170.48 ± 8.37 nm), PDI (0.19 ± 0.03), zeta potential (+ 26.73 mV), and entrapment efficiency (82.37 ± 2.48 %). In vitro drug release study displayed a sustained drug release pattern from RT-CH-NLCs-OPT (86.73±8.58 % in 24 h) in comparison to RT-Dis (98.61±7.24 % in 16 h). The permeability coefficient (PC) was found to be 11.39 ± 1.08×10^-4 cm.h^-1 and 2.34 folds higher than RT-Dis (4.85±1.53×10^-4 cm.h^-1). The relative bioavailability of RT from RT-CH-NLCs-OPT was 3.2-fold greater as compared to RT-Dis. The absolute bioavailability of RT after intranasal administration of RT-CH-NLCs-OPT was 2.1-fold higher than RT-CH-NLCs-OPT administered intravenously. The brain targeting and targeting potential was displayed by DTE (422.03 %) and DTP (76.03 %) after intranasal administration of RT-CH-NLCs-OPT as compared to RT-Dis (DTE 173.91 % and DTP 59.97 %). Furthermore, confocal laser scanning microscopy results confirmed better brain targeting for RT-CH-NLCs-OPT as compared to RT-Dis. From these findings, it could be concluded that RT-CH-NLCs could serve as a promising strategy for targeting RT through the intranasal route.

Chitosan-coated nanostructured lipid carriers for transdermal delivery of tetrahydrocurcumin for breast cancer therapy

Chitosan (Ch)-coated nanostructured lipid carriers (NLCs) have great potential for transdermal delivery with high localization of chemotherapeutics in breast cancer. This study used tetrahydrocurcumin (THC), a primary metabolite of curcumin with enhanced antioxidant and anticancer properties, as a model compound to prepare NLCs. Response surface methodology was employed to optimize THC-loaded Ch-coated NLCs (THC-Ch-NLCs) fabricated by high-shear homogenization. The optimized THC-Ch-NLCs had particle size of 244 ± 18 nm, zeta potential of -17.5 ± 0.5 mV, entrapment efficiency of 76.6 ± 0.2% and drug loading of 0.28 ± 0.01%. In vitro release study of THC-Ch-NLCs showed sustained release following the Korsmeyer-Peppas model with Fickian and non-Fickian diffusion at pH 7.4 and 5.5, respectively. THC-Ch-NLCs demonstrated significantly enhanced in vitro skin permeation, cell uptake, and remarkable cytotoxicity toward MD-MBA-231 breast cancer cells compared to the unencapsulated THC, suggesting Ch-NLCs as potential transdermal nanocarriers of THC for triple-negative breast cancer treatment.

Potential role of chitosan, PLGA and iron oxide nanoparticles in Parkinson’s disease therapy

Background

Parkinson's disease (PD) is a debilitating disease that alters an individual's functionality. Parkinsonism is a complex symptom consisting of numerous motor and non-motor features, and although several disorders are responsible, PD remains the most important. Several theories have been proposed for the characteristic pathological changes, the most important of which is the loss of dopaminergic neurons associated with a reduced ability to perform voluntary movements. Many drugs have been developed over the years to treat the condition and prevent its progression, but drug delivery is still a challenge due to the blood–brain barrier, which prevents the passage of drugs into the central nervous system. However, with the advances in nanotechnology in the medical field, there is growing hope of overcoming this challenge.

Summary

Our review highlights the potential role of three commonly studied nanoparticles in laboratory-induced animal models of PD: chitosan, PLGA, and iron oxide nanoparticles as potential PD therapy in humans.

Anti-Parkinsonian Therapy: Strategies for Crossing the Blood-Brain Barrier and Nano-Biological Effects of Nanomaterials

Parkinson's disease (PD), a neurodegenerative disease that shows a high incidence in older individuals, is becoming increasingly prevalent. Unfortunately, there is no clinical cure for PD, and novel anti-PD drugs are therefore urgently required. However, the selective permeability of the blood-brain barrier (BBB) poses a huge challenge in the development of such drugs. Fortunately, through strategies based on the physiological characteristics of the BBB and other modifications, including enhancement of BBB permeability, nanotechnology can offer a solution to this problem and facilitate drug delivery across the BBB. Although nanomaterials are often used as carriers for PD treatment, their biological activity is ignored. Several studies in recent years have shown that nanomaterials can improve PD symptoms via their own nano-bio effects. In this review, we first summarize the physiological features of the BBB and then discuss the design of appropriate brain-targeted delivery nanoplatforms for PD treatment. Subsequently, we highlight the emerging strategies for crossing the BBB and the development of novel nanomaterials with anti-PD nano-biological effects. Finally, we discuss the current challenges in nanomaterial-based PD treatment and the future trends in this field. Our review emphasizes the clinical value of nanotechnology in PD treatment based on recent patents and could guide researchers working in this area in the future.

Using nanotechnology to deliver biomolecules from nose to brain - peptides, proteins, monoclonal antibodies and RNA

There is a growing number of biomolecules, including peptides, proteins, monoclonal antibodies and RNA, that could be potentially used for the treatment of central nervous system (CNS) diseases. However, the realization of their potential is being hampered by the extraordinary difficulties these complex biomolecules have to reach the brain in therapeutically meaningful amounts. Nose-to-brain (N-to-B) delivery is now being investigated as a potential option for the direct transport of biomolecules from the nasal cavity to different brain areas. Here, we discuss how different technological approaches enhance this N-to-B transport, with emphasis on those that have shown a potential for clinical translation. We also analyse how the physicochemical properties of nanocarriers and their modification with cell-penetrating peptides (CPPs) and targeting ligands affect their efficacy as N-to-B carriers for biomolecules.

Dual effect of TAT functionalized DHAH lipid nanoparticles with neurotrophic factors in human BBB and microglia cultures

Background

Neurodegenerative diseases (NDs) are an accelerating global health problem. Nevertheless, the stronghold of the brain- the blood–brain barrier (BBB) prevents drug penetrance and dwindles effective treatments. Therefore, it is crucial to identify Trojan horse-like drug carriers that can effectively cross the blood–brain barrier and reach the brain tissue. We have previously developed polyunsaturated fatty acids (PUFA)-based nanostructured lipid carriers (NLC), namely DHAH-NLC. These carriers are modulated with BBB-permeating compounds such as chitosan (CS) and trans-activating transcriptional activator (TAT) from HIV-1 that can entrap neurotrophic factors (NTF) serving as nanocarriers for NDs treatment. Moreover, microglia are suggested as a key causative factor of the undergoing neuroinflammation of NDs. In this work, we used in vitro models to investigate whether DHAH-NLCs can enter the brain via the BBB and investigate the therapeutic effect of NTF-containing DHAH-NLC and DHAH-NLC itself on lipopolysaccharide-challenged microglia.

Methods

We employed human induced pluripotent stem cell-derived brain microvascular endothelial cells (BMECs) to capitalize on the in vivo-like TEER of this BBB model and quantitatively assessed the permeability of DHAH-NLCs. We also used the HMC3 microglia cell line to assess the therapeutic effect of NTF-containing DHAH-NLC upon LPS challenge.

Results

TAT-functionalized DHAH-NLCs successfully crossed the in vitro BBB model, which exhibited high transendothelial electrical resistance (TEER) values (≈3000 Ω*cm²). Specifically, the TAT-functionalized DHAH-NLCs showed a permeability of up to 0.4% of the dose. Furthermore, using human microglia (HMC3), we demonstrate that DHAH-NLCs successfully counteracted the inflammatory response in our cultures after LPS challenge. Moreover, the encapsulation of glial cell-derived neurotrophic factor (GNDF)-containing DHAH-NLCs (DHAH-NLC-GNDF) activated the Nrf2/HO-1 pathway, suggesting the triggering of the endogenous anti-oxidative system present in microglia.

Conclusions

Overall, this work shows that the TAT-functionalized DHAH-NLCs can cross the BBB, modulate immune responses, and serve as cargo carriers for growth factors; thus, constituting an attractive and promising novel drug delivery approach for the transport of therapeutics through the BBB into the brain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00315-1.

Pharmacokinetics and Pharmacodynamics of Intranasal Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for Nose-to-Brain Delivery

Nose-to-brain drug delivery has been of great interest for the treatment of many central nervous system (CNS) diseases and psychiatric disorders over past decades. Several nasally administered formulations have been developed to circumvent the blood-brain barrier and directly deliver drugs to the CNS through the olfactory and trigeminal pathways. However, the nasal mucosa’s drug absorption is insufficient and the volume of the nasal cavity is small, which, in combination, make nose-to-brain drug delivery challenging. These problems could be minimized using formulations based on solid lipid nanoparticles (SLNs) or nanostructured lipid carriers (NLCs), which are effective nose-to-brain drug delivery systems that improve drug bioavailability by increasing drug solubility and permeation, extending drug action, and reducing enzymatic degradation. Various research groups have reported in vivo pharmacokinetics and pharmacodynamics of SLNs and NLCs nose-to-brain delivery systems. This review was undertaken to provide an overview of these studies and highlight research performed on SLN and NLC-based formulations aimed at improving the treatment of CNS diseases such neurodegenerative diseases, epilepsy, and schizophrenia. We discuss the efficacies and brain targeting efficiencies of these formulations based on considerations of their pharmacokinetic parameters and toxicities, point out some gaps in current knowledge, and propose future developmental targets.

Lipid-Based Nanocarriers via Nose-to-Brain Pathway for Central Nervous System Disorders

Neurodegenerative disorders are distinguished by the gradual deterioration of the nervous system's structure and function due to oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation. Among these NDs, Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis characterized an increasing dysfunction and loss of neuronal structure leading to neuronal cell death. Although there is currently no drug to totally reverse the effects of NDs, such novel formulations and administration routes are developed for better management and nose-to-brain delivery is one of delivery for treating NDs. This review aimed to highlight advances in research on various lipid based nanocarriers such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and cubosomes which are reported to treat and alleviate the symptoms of NDs via nose-to-brain route. The challenges during clinical translation of lipid nanocarriers from bench to bed side is also discussed.

Superparamagnetic iron oxide loaded chitosan coated bilosomes for magnetic nose to brain targeting of resveratrol

The objective of this study was to improve effectiveness of resveratrol (RES) through brain targeting by the intranasal olfactory mucosa for the treatment Alzheimer's disease (AD). To attain this, chitosan coated bilosomes (non ionic surfactant vesicles stabilized by bile salts, loaded with RES and superparamagnetic iron oxide nanoparticles (SPIONs) were prepared and incorporated into sodium alginate/PVP wafers. In vitro characterization of bilosomes including colloidal characteristics, entrapment efficiency and in vitro release was carried out. Hydration capacity, porosity percentage, morphology and in vitro release for selected wafer formulation were also investigated. Particle size of selected bilosomes, CS coated bilosome and SPION bilosomes was 208, 238 and 243 nm, respectively and they provided sustained RES release for 24 h. Both formulations were loaded in wafers and intra-nasally administered in mice with lipopolysaccharide induced AD model. Neurobehavioral tests, AD markers analysis, RT-PCR, western blotting and histopathological evaluation of the dissected brains were carried out. Results revealed the superiority of SPION bilosomes over conventional bilosomes and RES suspension in improving cognitive and memory functions, reduction of pro-inflammatory markers levels and down regulation of expression of NF-κB and P38. This may be attributed to enhanced RES therapeutic effects upon nanoencapsulation, loading into wafers, nasal administration and enhanced targeting the application of an external magnetic field.

Growth Factor Therapy for Parkinson's Disease: Alternative Delivery Systems

Despite decades of research and billions in global investment, there remains no preventative or curative treatment for any neurodegenerative condition, including Parkinson's disease (PD). Arguably, the most promising approach for neuroprotection and neurorestoration in PD is using growth factors which can promote the growth and survival of degenerating neurons. However, although neurotrophin therapy may seem like the ideal approach for neurodegenerative disease, the use of growth factors as drugs presents major challenges because of their protein structure which creates serious hurdles related to accessing the brain and specific targeting of affected brain regions. To address these challenges, several different delivery systems have been developed, and two major approaches-direct infusion of the growth factor protein into the target brain region and in vivo gene therapy-have progressed to clinical trials in patients with PD. In addition to these clinically evaluated approaches, a range of other delivery methods are in various degrees of development, each with their own unique potential. This review will give a short overview of some of these alternative delivery systems, with a focus on ex vivo gene therapy and biomaterial-aided protein and gene delivery, and will provide some perspectives on their potential for clinical development and translation.

Interplay of BDNF and GDNF in the Mature Spinal Somatosensory System and Its Potential Therapeutic Relevance

The growth factors BDNF and GDNF are gaining more and more attention as modulators of synaptic transmission in the mature central nervous system (CNS). The two molecules undergo a regulated secretion in neurons and may be anterogradely transported to terminals where they can positively or negatively modulate fast synaptic transmission. There is today a wide consensus on the role of BDNF as a pro-nociceptive modulator, as the neurotrophin has an important part in the initiation and maintenance of inflammatory, chronic, and/or neuropathic pain at the peripheral and central level. At the spinal level, BDNF intervenes in the regulation of chloride equilibrium potential, decreases the excitatory synaptic drive to inhibitory neurons, with complex changes in GABAergic/glycinergic synaptic transmission, and increases excitatory transmission in the superficial dorsal horn. Differently from BDNF, the role of GDNF still remains to be unraveled in full. This review resumes the current literature on the interplay between BDNF and GDNF in the regulation of nociceptive neurotransmission in the superficial dorsal horn of the spinal cord. We will first discuss the circuitries involved in such a regulation, as well as the reciprocal interactions between the two factors in nociceptive pathways. The development of small molecules specifically targeting BDNF, GDNF and/or downstream effectors is opening new perspectives for investigating these neurotrophic factors as modulators of nociceptive transmission and chronic pain. Therefore, we will finally consider the molecules of (potential) pharmacological relevance for tackling normal and pathological pain.

Nanostructured Lipid Carriers Made of Ω-3 Polyunsaturated Fatty Acids: In Vitro Evaluation of Emerging Nanocarriers to Treat Neurodegenerative Diseases

Neurodegenerative diseases (ND) are one of the main problems of public health systems in the 21st century. The rise of nanotechnology-based drug delivery systems (DDS) has become in an emerging approach to target and treat these disorders related to the central nervous system (CNS). Among others, the use of nanostructured lipid carriers (NLCs) has increased in the last few years. Up to today, most of the developed NLCs have been made of a mixture of solid and liquid lipids without any active role in preventing or treating diseases. In this study, we successfully developed NLCs made of a functional lipid, such as the hydroxylated derivate of docohexaenoic acid (DHAH), named DHAH-NLCs. The newly developed nanocarriers were around 100 nm in size, with a polydispersity index (PDI) value of <0.3, and they exhibited positive zeta potential due to the successful chitosan (CS) and TAT coating. DHAH-NLCs were shown to be safe in both dopaminergic and microglia primary cell cultures. Moreover, they exhibited neuroprotective effects in dopaminergic neuron cell cultures after exposition to 6-hydroxydopamine hydrochloride (6-OHDA) neurotoxin and decreased the proinflammatory cytokine levels in microglia primary cell cultures after lipopolysaccharide (LPS) stimuli. The levels of the three tested cytokines, IL-6, IL-1β and TNF-α were decreased almost to control levels after the treatment with DHAH-NLCs. Taken together, these data suggest the suitability of DHAH-NLCs to attaining enhanced and synergistic effects for the treatment of NDs.

A Reevaluation of Chitosan-Decorated Nanoparticles to Cross the Blood-Brain Barrier

The blood-brain barrier (BBB) is a sophisticated and very selective dynamic interface composed of endothelial cells expressing enzymes, transport systems, and receptors that regulate the passage of nutrients, ions, oxygen, and other essential molecules to the brain, regulating its homeostasis. Moreover, the BBB performs a vital function in protecting the brain from pathogens and other dangerous agents in the blood circulation. Despite its crucial role, this barrier represents a difficult obstacle for the treatment of brain diseases because many therapeutic agents cannot cross it. Thus, different strategies based on nanoparticles have been explored in recent years. Concerning this, chitosan-decorated nanoparticles have demonstrated enormous potential for drug delivery across the BBB and treatment of Alzheimer's disease, Parkinson's disease, gliomas, cerebral ischemia, and schizophrenia. Our main objective was to highlight the high potential of chitosan adsorption to improve the penetrability through the BBB of nanoformulations for diseases of CNS. Therefore, we describe the BBB structure and function, as well as the routes of chitosan for crossing it. Moreover, we define the methods of decoration of nanoparticles with chitosan and provide numerous examples of their potential utilization in a variety of brain diseases. Lastly, we discuss future directions, mentioning the need for extensive characterization of proposed nanoformulations and clinical trials for evaluation of their efficacy.

Improving therapeutic potential of GDNF family ligands

The last decade has been a frustrating time for investigators who had envisioned major advances in the treatment of Parkinson’s disease using neurotrophic factors. The first trials of glial cell line–derived neurotrophic factor for treating Parkinson’s disease were very promising. Later blinded control trials were disappointing, not reaching the predetermined outcomes for improvement in motor function. Consideration of the problems in the studies as well as the biology of the neurotrophins used can potentially lead to more effective therapies. Parkinson’s disease presents a multitude of opportunities for the cell biologist wanting to understand its pathology and to find possible new avenues for treatment.

Double Optimization of Rivastigmine-Loaded Nanostructured Lipid Carriers (NLC) for Nose-to-Brain Delivery Using the Quality by Design (QbD) Approach: Formulation Variables and Instrumental Parameters

Rivastigmine is a drug commonly used in the management of Alzheimer's disease that shows bioavailability problems. To overcome this, the use of nanosystems, such as nanostructured lipid carriers (NLC), administered through alternative routes seems promising. In this work, we performed a double optimization of a rivastigmine-loaded NLC formulation for direct drug delivery from the nose to the brain using the quality by design (QbD) approach, whereby the quality target product profile (QTPP) was the requisite for nose to brain delivery. The experiments started with the optimization of the formulation variables (or critical material attributes-CMAs) using a central composite design. The rivastigmine-loaded NLC formulations with the best critical quality attributes (CQAs) of particle size, polydispersity index (PDI), zeta potential (ZP), and encapsulation efficiency (EE) were selected for the second optimization, which was related to the production methods (ultrasound technique and high-pressure homogenization). The most suitable instrumental parameters for the production of NLC were analyzed through a Box-Behnken design, with the same CQAs being evaluated for the first optimization. For the second part of the optimization studies, were selected two rivastigmine-loaded NLC formulations: one produced by ultrasound technique and the other by the high-pressure homogenization (HPH) method. Afterwards, the pH and osmolarity of these formulations were adjusted to the physiological nasal mucosa values and in vitro drug release studies were performed. The results of the first part of the optimization showed that the most adequate ratios of lipids and surfactants were 7.49:1.94 and 4.5:0.5 (%, w/w), respectively. From the second part of the optimization, the results for the particle size, PDI, ZP, and EE of the rivastigmine-loaded NLC formulations produced by ultrasound technique and HPH method were, respectively, 114.0 ± 1.9 nm and 109.0 ± 0.9 nm; 0.221 ± 0.003 and 0.196 ± 0.007; -30.6 ± 0.3 mV and -30.5 ± 0.3 mV; 97.0 ± 0.5% and 97.2 ± 0.3%. Herein, the HPH was selected as the most suitable production method, although the ultrasound technique has also shown effectiveness. In addition, no significant changes in CQAs were observed after 90 days of storage of the formulations at different temperatures. In vitro studies showed that the release of rivastigmine followed a non-Fickian mechanism, with an initial fast drug release followed by a prolonged release over 48 h. This study has optimized a rivastigmine-loaded NLC formulation produced by the HPH method for nose-to-brain delivery of rivastigmine. The next step is for in vitro and in vivo experiments to demonstrate preclinical efficacy and safety. QbD was demonstrated to be a useful approach for the optimization of NLC formulations for which specific physicochemical requisites can be identified.

Recent strategies and advances in the fabrication of nano lipid carriers and their application towards brain targeting

In last two decades, the lipid nanocarriers have been extensively investigated for their drug targeting efficiency towards the critical areas of the human body like CNS, cardiac region, tumor cells, etc. Owing to the flexibility and biocompatibility, the lipid-based nanocarriers, including nanoemulsion, liposomes, SLN, NLC etc. have gained much attention among various other nanocarrier systems for brain targeting of bioactives. Across different lipid nanocarriers, NLC remains to be the safest, stable, biocompatible and cost-effective drug carrier system with high encapsulation efficiency. Drug delivery to the brain always remains a challenging issue for scientists due to the complex structure and various barrier mechanisms surrounding the brain. The application of a suitable nanocarrier system and the use of any alternative route of drug administration like nose-to-brain drug delivery could overcome the hurdle and improves the therapeutic efficiency of CNS acting drugs thereof. NLC, a second-generation lipid nanocarrier, upsurges the drug permeation across the BBB due to its unique structural properties. The biocompatible lipid matrix and nano-size make it an ideal drug carrier for brain targeting. It offers many advantages over other drug carrier systems, including ease of manufacturing and scale-up to industrial level, higher drug targeting, high drug loading, control drug release, compatibility with a wide range of drug substances, non-toxic and non-irritant behavior. This review highlights recent progresses towards the development of NLC for brain targeting of bioactives with particular reference to its surface modifications, formulations aspects, pharmacokinetic behavior and efficacy towards the treatment of various neurological disorders like AD, PD, schizophrenia, epilepsy, brain cancer, CNS infection (viral and fungal), multiple sclerosis, cerebral ischemia, and cerebral malaria. This work describes in detail the role and application of NLC, along with its different fabrication techniques and associated limitations. Specific emphasis is given to compile a summary and graphical data on the area explored by scientists and researchers worldwide towards the treatment of neurological disorders with or without NLC. The article also highlights a brief insight into two prime approaches for brain targeting, including drug delivery across BBB and direct nose-to-brain drug delivery along with the current global status of specific neurological disorders.

Lipid-based nanodelivery approaches for dopamine-replacement therapies in Parkinson's disease: From preclinical to translational studies

The incidence of Parkinson's disease (PD), the second most common neurodegenerative disorder, has increased exponentially as the global population continues to age. Although the etiological factors contributing to PD remain uncertain, its average incidence rate is reported to be 1% of the global population older than 60 years. PD is primarily characterized by the progressive loss of dopaminergic (DAergic) neurons and/or associated neuronal networks and the subsequent depletion of dopamine (DA) levels in the brain. Thus, DA or levodopa (l-dopa), a precursor of DA, represent cardinal targets for both idiopathic and symptomatic PD therapeutics. While several therapeutic strategies have been investigated over the past decade for their abilities to curb the progression of PD, an effective cure for PD is currently unavailable. Even DA replacement therapy, an effective PD therapeutic strategy that provides an exogenous supply of DA or l-dopa, has been hindered by severe challenges, such as a poor capacity to bypass the blood-brain barrier and inadequate bioavailability. Nevertheless, with recent advances in nanotechnology, several drug delivery systems have been developed to bypass the barriers associated with central nervous system therapeutics. In here, we sought to describe the adapted lipid-based nanodrug delivery systems used in the field of PD therapeutics and their recent advances, with a particular focus placed on DA replacement therapies. This work initially explores the background of PD; offers descriptions of the most recent molecular targets; currently available clinical medications/limitations; an overview of several lipid-based PD nanotherapeutics, functionalized nanoparticles, and technical aspects in brain delivery; and, finally, presents future perspectives to enhance the use of nanotherapeutics in PD treatment.

Intranasal delivery of mucoadhesive nanocarriers: a viable option for Parkinson's disease treatment?

Introduction: Intranasal drug delivery is a largely unexplored, promising approach for the treatment of various neurological disorders. However, due to the challenging constraints available in the pathway of nose-to-brain delivery, finding an effective treatment for Parkinsonism is still an impending mission for research workers. This warrants development of novel treatment alternatives for Parkinson's disease (PD). Intranasal delivery of mucoadhesive nanocarriers is one such novel approach which might help in curbing the glitches associated with the currently available therapy.Areas covered: This review summarizes the evidences supporting nose-to-brain delivery of polymer-based mucoadhesive nanocarriers for the treatment of PD. A concise insight into the lipid-based mucoadhesive nanocarriers has also been presented. The recent researches have been compiled pertaining to the use of mucoadhesive nanocarrriers for improving the treatment outcomes of PD via intranasal drug delivery.Expert opinion: Although the use of nanocarrier-based strategies for site-specific delivery via intranasal route has proven effective, the magnitude of improvement remains moderate resulting in limited translation from industry to the market. Comprehensive understanding of the mucoadhesive polymer, its characteristics and mechanisms involved for an effective nose-to-brain uptake of the drug is a promising avenue to develop novel formulations for effective management of Parkinson disease.

Inhibition of p38 MAPK in the brain through nasal administration of p38 inhibitor loaded in chitosan nanocapsules

Aim: To determine whether a p38 MAPK inhibitor incorporated into nanoemulsion-based chitosan nanocapsules can reduce the activity of this kinase in the brain through their nasal administration in mice. Materials & methods: We selected the p38 MAPK inhibitor PH797804, an ATP-competitive inhibitor of p38α encapsulated in nanoemulsion-based chitosan nanocapsules. Biological effect was evaluated in microglial and neuronal cells in vitro and in ex vivo and in vivo systems, in a mouse model of Alzheimer's disease. Results: Encapsulated inhibitor retains enzymatic inhibitory activity and tissue penetration capacity in vitro, ex vivo and in vivo. Conclusion: Nasal administration of chitosan nanocapsules can be an effective approach for brain-restricted reduction of p38 MAPK activity, thus reducing the side effects of systemic administration.

Nanosized nasal emulgel of resveratrol: preparation, optimization, in vitro evaluation and in vivo pharmacokinetic study

Nano-emulgel has become one of the most significant controlled release systems, which has the advantages of both gels and nano-emulsions. This work aims at the formulation of nasal nano-emulgel for resveratrol, employing carbopol 934 and poloxamer 407 as the gelling agents. The optimum nano-emulsion was determined through further characterization of the selected system. The nasal nano-emulgel was prepared and tested for the in vitro release, the release kinetics, FTIR, ex vivo permeation, nasal mucosa toxicity, and in vivo pharmacokinetic study. The optimum nano-emulsion consisted of Tween 20, Capryol 90, and Transcutol at a ratio of (54.26: 23.81: 21.93%v/v), and it exhibited transmittance of 100%, resveratrol solubility of 159.9 ± 6.4 mg/mL, globule size of 30.65 nm. The in vitro resveratrol released from nano-emulsion and nasal nano-emulgel was 96.17 ± 4.43% and 78.53 ± 4.7%, respectively. Ex vivo permeation was sustained during 12 h up to 63.95 ± 4.7%. The histopathological study demonstrated that the formula is safe and tolerable to the nasal mucosa. C_max and AUC _(0-∞) of resveratrol obtained after nasal administration of nasal nano-emulgel was 2.23 and 8.05 times, respectively. Similarly, T_max was increased up to 3.67 ± 0.82 h. The optimized nasal nano-emulgel established intranasal safety and bioavailability enhancement so it is considered as a well-designed system to target the brain.

Hybrid Ofloxacin/eugenol co-loaded solid lipid nanoparticles with enhanced and targetable antimicrobial properties

In the global context of an imminent emergence of multidrug-resistant microorganisms, the present work combined the use of nanotechnology and the therapeutic benefits of natural compounds as a strategy to potentiate antimicrobial action of the wide-spectrum antibiotic Ofloxacin (Ofx). Hybrid solid lipid nanoparticles (SLN) were synthesized by incorporation of chitosan (Chi, a cationic biopolymer with antimicrobial activity) and eugenol (Eu, a phenolic compound that interferes with bacterial quorum sensing) into a lipid matrix by hot homogenization/ultrasonication method. The developed SLN/Chi/Eu sustainably released the encapsulated Ofx for 24 h. Characterization by DLS, TEM, DSC, TGA and XRD revealed the presence of positively charged spherical nanoparticles with diameters around 300 nm and Ofx entrapped in amorphous state. The SLN exhibited an enhanced bactericidal activity against Pseudomonas aeruginosa and Staphylococcus aureus. The minimum inhibitory concentration (MIC) for free and nanoencapsulated Ofx formulations was below 1.0 µg/ml. The MIC values decreased by 6.1- to 16.1-fold when Ofx was encapsulated in SLN/Chi/Eu. Fluorescent-labeled nanoparticles had the ability to interact with the bacterial cell membrane. Selective toxicity of SLN/Chi/Eu-Ofx was tested in the range of 0.3-30.0 µg/ml and showed no toxicity up to 3.0 µg/ml Ofx in human cell models (A549 and Wi-38) at 24 h and 48 h exposure. It was proved that the administration of hybrid SLN to mice by dry powder inhalation reached therapeutic Ofx levels in lungs.

Brain targeting of resveratrol through intranasal lipid vesicles labelled with gold nanoparticles: in vivo evaluation and bioaccumulation investigation using computed tomography and histopathological examination

Resveratrol is a promising neuroprotective agent against neurodegenerative disorders such as Alzheimer's disease. Resveratrol-loaded transferosomes and nanoemulsions were developed and labelled with gold nanoparticles (GNPs). The water maze test was utilised to identify the effect on spatial memory recovery. The treated rats were examined for cellular uptake and bioaccumulation of drug in the brain using computed tomography (CT) and histopathological examination utilising GNPs as a biomarker. Compared with nanoemulsions, transferosomes displayed higher permeation of up to 81.29 ± 2.64% and higher fluorescence intensity with p < .05. Transferosomes significantly enhanced behavioural acquisition and spatial memory function in the amnesic rats compared with both the nanoemulsion formulation and the pure drug. CT effectively demonstrated the accumulation of GNPs in the brains of all treated rats, while superior accumulation of GNPs was observed in the rats that received the transferosome formulation. The histopathology also demonstrated GNP accumulation in the nuclei and cytoplasm in the brain tissues of both the transferosome- and nanoemulsion-treated groups. Therefore, the developed transferosomes may be considered as a well-designed brain targeting system that might further be applied for targeting many drugs to be used in the treatment of central nervous system diseases.

Nanosized Transferosome-Based Intranasal In Situ Gel for Brain Targeting of Resveratrol: Formulation, Optimization, In Vitro Evaluation, and In Vivo Pharmacokinetic Study

Resveratrol (RES) is a potent antioxidant used for the management of several central nervous system diseases. RES bioavailability is less than 1 owing to its low solubility and extensive intestinal and hepatic metabolism. The aim of the study was to enhance RES bioavailability through developing intranasal transferosomal mucoadhesive gel. Reverse evaporation-vortexing sonication method was employed to prepare RES-loaded transferosomes. Transferosomes were developed via 3⁴ definitive screening design, using soya lecithin, permeation enhancers, and surfactants. The optimized formula displayed spherical shape with vesicle size of 83.79 ± 2.54 nm and entrapment efficiency (EE%) of 72.58 ± 4.51%. Mucoadhesive gels were prepared and evaluated, then optimized RES transferosomes were incorporated into the selected gel and characterized using FTIR spectroscopy, in vitro release, and ex vivo permeation study. Histopathological examination of nasal mucosa and in vivo pharmacokinetic study were conducted. In vitro drug release from transferosomal gel was 65.87 ± 2.12% and ex vivo permeation was 75.95 ± 3.19%. Histopathological study confirmed the safety of the optimized formula. The C_max of RES in the optimized RES trans-gel was 2.15 times higher than the oral RES suspension and AUC_(0-∞) increased by 22.5 times. The optimized RES trans-gel developed intranasal safety and bioavailability enhancement through passing hepatic and intestinal metabolism.

Nanodelivery of therapeutic agents in Parkinson's disease

Parkinson's disease (PD) as a motor disorder is pathologically featured by the loss of dopaminergic neurons of the substantia nigra compacta (SNc) and the consequent depletion of dopamine in the striatum. However, motor signs are detectable when the loss of dopaminergic striatal terminals exceeds to the dopaminergic neuronal degeneration in SN. Hence, recent evidences about the topological organization of the nigrostriatal system could provide novel insights about the progression of the neurodegenerative process as well as the correct application of the novel therapeutic strategies. Though dopaminergic drugs and different routes of administration have been proposed to treat PD, most of the effects are symptomatic with temporary effects resorting to invasive procedures to ameliorate the side effects. Since the blood-brain barrier (BBB) is the main obstacle for most of molecules to access to the brain, ongoing research is focused on halting the progression of PD through the use of those technologies that allow the effective delivery and diffusion of therapeutic molecules to the central nervous system for bypassing BBB and avoiding the side effects. In this context, nanotechnology is emerging as a promising tool for drug delivery. In fact, nanodelivery of restorative treatments in PD, such as gene therapy increased the effectiveness of neurotrophic factors for restoring the dopamine deficit and improving motor deficit in rodent models. Therefore, the present review is focused on the description and identification of the available nanotherapies developed in experimental models of PD which could suppose an important advance for controlled delivery of nanobioactive components into the brain and one more step for the clinical projection.

Beneficial effects of n-3 polyunsaturated fatty acids administration in a partial lesion model of Parkinson's disease: The role of glia and NRf2 regulation

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been widely associated to beneficial effect over different neurodegenerative diseases. In the present study, we tested the potential therapeutic effect of docohexanoic acid (DHA) and its hydroxylated derivate, DHAH, in a partial lesion model of Parkinson's disease (PD). One month before and four months after the striatal lesion with 6-OHDA was made, the animals were daily treated with DHA (50 mg/kg), DHAH (50 mg/kg), vehicle or saline, by intragastric administration. Animal groups under n-3 PUFA treatments exhibited a trend to improve in amphetamine-induced rotations and cylinder test. The beneficial effect seen in behavioral studies were confirmed with TH immunostaining. TH⁺ fibers and TH⁺ neurons increased in the experimental groups treated with both n-3 PUFAs, DHA and DHAH. Moreover, the n-3 PUFAs administration decreased the astrogliosis and microgliosis, in both the striatum and substantia nigra (SN), with a higher decrease of GFAP⁺ and Iba-1⁺ cells for the DHAH treated group. This experimental group also revealed a positive effect on Nrf2 pathway regulation, decreasing the positive Nrf2 immmunostaining in the striatum and SN, which revealed a potential antioxidant effect of this compound. Taking together, these data suggest a positive effect of n-3 PUFAs administration, and more concretely of DHAH, for PD treatment as it exhibited positive results on dopaminergic system, neuroinflammation and oxidative stress.

Antibody-functionalized polymer nanoparticle leading to memory recovery in Alzheimer's disease-like transgenic mouse model

Alzheimer's disease (AD) is a neurodegenerative disorder related, in part, to the accumulation of amyloid-β peptide (Aβ) and especially the Aβ peptide 1-42 (Aβ_1-42). The aim of this study was to design nanocarriers able to: (i) interact with the Aβ_1-42 in the blood and promote its elimination through the "sink effect" and (ii) correct the memory defect observed in AD-like transgenic mice. To do so, biodegradable, PEGylated nanoparticles were surface-functionalized with an antibody directed against Aβ_1-42. Treatment of AD-like transgenic mice with anti-Aβ_1-42-functionalized nanoparticles led to: (i) complete correction of the memory defect; (ii) significant reduction of the Aβ soluble peptide and its oligomer level in the brain and (iii) significant increase of the Aβ levels in plasma. This study represents the first example of Aβ_1-42 monoclonal antibody-decorated nanoparticle-based therapy against AD leading to complete correction of the memory defect in an experimental model of AD.

Nose-to-brain peptide delivery - The potential of nanotechnology

Nose-to-brain (N-to-B) delivery offers to protein and peptide drugs the possibility to reach the brain in a non-invasive way. This article is a comprehensive review of the state-of-the-art of this emerging peptide delivery route, as well as of the challenges associated to it. Emphasis is given on the potential of nanosized drug delivery carriers to enhance the direct N-to-B transport of protein or peptide drugs. In particular, polymer- and lipid- based nanocarriers are comparatively analyzed in terms of the influence of their physicochemical characteristics and composition on their in vivo fate and efficacy. The use of biorecognitive ligands and permeation enhancers in order to enhance their brain targeting efficiency is also discussed. The article concludes highlighting the early stage of this research field and its still unveiled potential. The final message is that more explicatory PK/PD studies are required in order to achieve the translation from preclinical to the clinical development phase.

Nanoformulation: A Useful Therapeutic Strategy for Improving Neuroprotection and the Neurorestorative Potential in Experimental Models of Parkinson's Disease

Parkinson's disease (PD) is the second most frequent neurodegenerative disorder, but current therapies are only symptomatic. Experimental models are necessary to go deeper in the comprehension of pathophysiological mechanism and to assess new therapeutic strategies. The unilateral 6-hydroxydopamine (6-OHDA) lesion either in medial forebrain bundle (MFB) or into the striatum in rats affords to study various stages of PD depending on the evolution time lapsed. A promising alternative to address the neurodegenerative process is the use of neurotrophic factors; but its clinical use has been limited due to its short half-life and rapid degradation after in vivo administration, along with difficulties for crossing the blood-brain barrier (BBB). Tyrosine hydroxylase (TH) immunostaining revealed a significant decrease of the TH-immunopositive striatal volume in 6-OHDA group from rostral to caudal one. The loss of TH-ir neurons and axodendritic network (ADN) was higher in caudal sections showing a selective vulnerability of the topological distributed dopaminergic system. In addition to a remarkable depletion of dopamine in the nigrostriatal system, the administration of 6-OHDA into MFB induces some other neuropathological changes such as an increase of glial fibrillary acidic protein (GFAP) positive cells in substantia nigra (SN) as well as in striatum. Intrastriatal implantation of micro- or nanosystems delivering neurotrophic factor in parkinsonized rats for bypassing BBB leads to a significative functional and morphological recovery. Neurorestorative morphological changes (preservation of the TH-ir cells and ADN) along the rostrocaudal axis of caudoputamen complex and SN have been probed supporting a selective recovering after the treatment as well. Others innovative therapeutic strategies, such as the intranasal delivery, have been recently assessed in order to search the NTF effects. In addition some others methodological key points are reviewed.