Rescuing apoptotic neurons in Alzheimer's disease using wheat germ agglutinin-conjugated and cardiolipin-conjugated liposomes with encapsulated nerve growth factor and curcumin

Nanomaterials that Aid in the Diagnosis and Treatment of Alzheimer's Disease, Resolving Blood-Brain Barrier Crossing Ability

As a form of dementia, Alzheimer's disease (AD) suffers from no efficacious cure, yet AD treatment is still imperative, as it ameliorates the symptoms or prevents it from deteriorating or maintains the current status to the longest extent. The human brain is the most sensitive and complex organ in the body, which is protected by the blood-brain barrier (BBB). This yet induces the difficulty in curing AD as the drugs or nanomaterials that are much inhibited from reaching the lesion site. Thus, BBB crossing capability of drug delivery system remains a significant challenge in the development of neurological therapeutics. Fortunately, nano-enabled delivery systems possess promising potential to achieve multifunctional diagnostics/therapeutics against various targets of AD owing to their intriguing advantages of nanocarriers, including easy multifunctionalization on surfaces, high surface-to-volume ratio with large payloads, and potential ability to cross the BBB, making them capable of conquering the limitations of conventional drug candidates. This review, which focuses on the BBB crossing ability of the multifunctional nanomaterials in AD diagnosis and treatment, will provide an insightful vision that is conducive to the development of AD-related nanomaterials.

Exploring Curcumin-Loaded Lipid-Based Nanomedicine as Efficient Targeted Therapy for Alzheimer's Diseases

Alzheimer's disease (AD) is a neurological condition currently with 47 million people suffering from it globally. AD might have many reasons such as genetic issues, environmental factors, and Aβ accumulation, which is the biomarker of the disease. Since the primary reason is unknown, there is no targeted treatment at the moment, but ongoing research aims to slow its progression by managing amyloid-beta peptide production rather than symptomatic improvement. Since phytochemicals have been demonstrated to possess antioxidant, anti-inflammatory, and neuroprotective properties, they may target multiple pathological factors and can reduce the risk of the disease. Curcumin, as a phytochemical found in turmeric known for its antioxidant, free radical scavenging properties, and as an antiamyloid in treating AD, has come under investigation. Although its low bioavailability limits its efficacy, a prominent drug delivery system (DDS) is desired to overcome it. Hence, the potency of lipid-based nanoparticles encapsulating curcumin (LNPs-CUR) is considered in this study as a promising DDS. In vivo studies in animal models indicate LNPs-CUR effectively slow amyloid plaque formation, leading to cognitive enhancement and reduced toxicity compared to free CUR. However, a deeper understanding of CUR's pharmacokinetics and safety profile is crucial before LNPs-CUR can be considered as a medicine. Future investigations may explore the combination of NPs with other therapeutic agents to increase their efficacy in AD cases. This review provides the current position of CUR in the AD therapy paradigm, the DDS suggestions for CUR, and the previous research from the point of analytical view focused on the advantages and challenges.

Biomaterials-based anti-inflammatory treatment strategies for Alzheimer's disease

The current therapeutic drugs for Alzheimer's disease only improve symptoms, they do not delay disease progression. Therefore, there is an urgent need for new effective drugs. The underlying pathogenic factors of Alzheimer's disease are not clear, but neuroinflammation can link various hypotheses of Alzheimer's disease; hence, targeting neuroinflammation may be a new hope for Alzheimer's disease treatment. Inhibiting inflammation can restore neuronal function, promote neuroregeneration, reduce the pathological burden of Alzheimer's disease, and improve or even reverse symptoms of Alzheimer's disease. This review focuses on the relationship between inflammation and various pathological hypotheses of Alzheimer's disease; reports the mechanisms and characteristics of small-molecule drugs (e.g., nonsteroidal anti-inflammatory drugs, neurosteroids, and plant extracts); macromolecule drugs (e.g., peptides, proteins, and gene therapeutics); and nanocarriers (e.g., lipid-based nanoparticles, polymeric nanoparticles, nanoemulsions, and inorganic nanoparticles) in the treatment of Alzheimer's disease. The review also makes recommendations for the prospective development of anti-inflammatory strategies based on nanocarriers for the treatment of Alzheimer's disease.

Recent Advancements in Nanocarrier-assisted Brain Delivery of Phytochemicals Against Neurological Diseases

Despite ongoing advancements in research, the inability of therapeutics to cross the blood-brain barrier (BBB) makes the treatment of neurological disorders (NDs) a challenging task, offering only partial symptomatic relief. Various adverse effects associated with existing approaches are another significant barrier that prompts the usage of structurally diverse phytochemicals as preventive/therapeutic lead against NDs in preclinical and clinical settings. Despite numerous beneficial properties, phytochemicals suffer from poor pharmacokinetic profile which limits their pharmacological activity and necessitates the utility of nanotechnology for efficient drug delivery. Nanocarriers have been shown to be proficient carriers that can enhance drug delivery, bioavailability, biocompatibility, and stability of phytochemicals. We, thus, conducted a meticulous literature survey using several electronic databases to gather relevant studies in order to provide a comprehensive summary about the use of nanocarriers in delivering phytochemicals as a treatment approach for NDs. Additionally, the review highlights the mechanisms of drug transport of nanocarriers across the BBB and explores their potential future applications in this emerging field.

Conjugation, Prodrug, and Co-Administration Strategies in Support of Nanotechnologies to Improve the Therapeutic Efficacy of Phytochemicals in the Central Nervous System

Phytochemicals, produced as secondary plant metabolites, have shown interesting potential therapeutic activities against neurodegenerative diseases and cancer. Unfortunately, poor bioavailability and rapid metabolic processes compromise their therapeutic use, and several strategies are currently proposed for overcoming these issues. The present review summarises strategies for enhancing the central nervous system's phytochemical efficacy. Particular attention has been paid to the use of phytochemicals in combination with other drugs (co-administrations) or administration of phytochemicals as prodrugs or conjugates, particularly when these approaches are supported by nanotechnologies exploiting conjugation strategies with appropriate targeting molecules. These aspects are described for polyphenols and essential oil components, which can improve their loading as prodrugs in nanocarriers, or be part of nanocarriers designed for targeted co-delivery to achieve synergistic anti-glioma or anti-neurodegenerative effects. The use of in vitro models, able to simulate the blood-brain barrier, neurodegeneration or glioma, and useful for optimizing innovative formulations before their in vivo administration via intravenous, oral, or nasal routes, is also summarised. Among the described compounds, quercetin, curcumin, resveratrol, ferulic acid, geraniol, and cinnamaldehyde can be efficaciously formulated to attain brain-targeting characteristics, and may therefore be therapeutically useful against glioma or neurodegenerative diseases.

Curcumin-Based Nanomedicines in the Treatment of Inflammatory and Immunomodulated Diseases: An Evidence-Based Comprehensive Review

Curcumin (CUR) is a polyphenol extracted from the rhizome of Curcuma longa that possesses potent anti-inflammatory and antioxidant potential. Despite CUR's numerous beneficial effects on human health, it has limitations, such as poor absorption. Nano-based drug delivery systems have recently been applied to improve CUR's solubility and bioavailability and potentialize its health effects. This review investigated the effects of different CUR-based nanomedicines on inflammatory and immunomodulated diseases. PUBMED, EMBASE, COCHRANE, and GOOGLE SCHOLAR databases were searched, and the Scale for Assessment of Narrative Review Articles (SANRA) was used for quality assessment and PRISMA guidelines. Overall, 66 studies were included comprising atherosclerosis, rheumatoid arthritis (RA), Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), Huntington's disease (HD), inflammatory bowel diseases (IBD), psoriasis, liver fibrosis, epilepsy, and COVID-19. The available scientific studies show that there are many known nanoformulations with curcumin. They can be found in nanosuspensions, nanoparticles, nanoemulsions, solid lipid particles, nanocapsules, nanospheres, and liposomes. These formulations can improve CUR bioavailability and can effectively be used as adjuvants in several inflammatory and immune-mediated diseases such as atheroma plaque formation, RA, dementia, AD, PD, MS, IBD, psoriasis, epilepsy, COVID-19, and can be used as potent anti-fibrotic adjuvants in fibrotic liver disease.

Exosome-based approaches in the management of Alzheimer's disease

Alzheimer's disease (AD) has been the most extensively studied neurological disorders that affects millions of individuals globally and is associated with misfolding of proteins in the brain. Amyloid-β and tau are predominantly involved in the pathogenesis of AD. Therapeutic interventions and nanotechnological advancements are useful only in managing the AD symptoms and the cure for this disease remains elusive. Exosomes, originating from most cell and tissue types are regarded as a double-edged sword, considering their roles in the progression and treatment of AD. Exosomes can be manipulated as drug delivery vehicles for a wide range of therapeutic cargos-both small molecules and macromolecules. Herein, we review the roles of exosomes in the pathology, diagnosis, and treatment of AD and highlight their application as a drug carrier to the brain for AD treatment.

Liposome based drug delivery as a potential treatment option for Alzheimer's disease

Alzheimer's disease is a neurodegenerative condition leading to atrophy of the brain and robbing nearly 5.8 million individuals in the United States age 65 and older of their cognitive functions. Alzheimer's disease is associated with dementia and a progressive decline in memory, thinking, and social skills, eventually leading to a point that the individual can no longer perform daily activities independently. Currently available drugs on the market temporarily alleviate the symptoms, however, they are not successful in slowing down the progression of Alzheimer's disease. Treatment and cures have been constricted due to the difficulty of drug delivery to the blood-brain barrier. Several studies have led to identification of vesicles to transport the necessary drugs through the blood-brain barrier that would typically not achieve the targeted area through systemic delivered medications. Recently, liposomes have emerged as a viable drug delivery agent to transport drugs that are not able to cross the blood-brain barrier. Liposomes are being used as a component of nanoparticle drug delivery; due to their biocompatible nature; and possessing the capability to carry both lipophilic and hydrophilic therapeutic agents across the blood brain barrier into the brain cells. Studies indicate the importance of liposomal based drug delivery in treatment of neurodegenerative disorders. The idea is to encapsulate the drugs inside the properly engineered liposome to generate a response of treatment. Liposomes are engineered to target specific diseased moieties and also several surface modifications of liposomes are under research to create a clinical path to the management of Alzheimer's disease. This review deals with Alzheimer's disease and emphasize on challenges associated with drug delivery to the brain, and how liposomal drug delivery can play an important role as a drug delivery method for the treatment of Alzheimer's disease. This review also sheds some light on variation of liposomes. Additionally, it emphasizes on the liposomal formulations which are currently researched or used for treatment of Alzheimer's disease and also discusses the future prospect of liposomal based drug delivery in Alzheimer's disease.

Broad-Spectrum Theranostics and Biomedical Application of Functionalized Nanomaterials

Nanotechnology is an important branch of science in therapies known as “nanomedicine” and is the junction of various fields such as material science, chemistry, biology, physics, and optics. Nanomaterials are in the range between 1 and 100 nm in size and provide a large surface area to volume ratio; thus, they can be used for various diseases, including cardiovascular diseases, cancer, bacterial infections, and diabetes. Nanoparticles play a crucial role in therapy as they can enhance the accumulation and release of pharmacological agents, improve targeted delivery and ultimately decrease the intensity of drug side effects. In this review, we discussthe types of nanomaterials that have various biomedical applications. Biomolecules that are often conjugated with nanoparticles are proteins, peptides, DNA, and lipids, which can enhance biocompatibility, stability, and solubility. In this review, we focus on bioconjugation and nanoparticles and also discuss different types of nanoparticles including micelles, liposomes, carbon nanotubes, nanospheres, dendrimers, quantum dots, and metallic nanoparticles and their crucial role in various diseases and clinical applications. Additionally, we review the use of nanomaterials for bio-imaging, drug delivery, biosensing tissue engineering, medical devices, and immunoassays. Understandingthe characteristics and properties of nanoparticles and their interactions with the biological system can help us to develop novel strategies for the treatment, prevention, and diagnosis of many diseases including cancer, pulmonary diseases, etc. In this present review, the importance of various kinds of nanoparticles and their biomedical applications are discussed in much detail.

Nerve Growth Factor Protects Against Pyrethroid-Induced Endoplasmic Reticulum (ER) Stress in Primary Hippocampal Neurons

Neurotrophins are a family of growth factors crucial for growth and survival of neurons in the developing and adult brain. Reduction in neurotrophin levels is associated with reduced neurogenesis and cognitive deficits in rodents. Recently, we demonstrated that long-term exposure to low levels of the pyrethroid pesticide deltamethrin causes hippocampal endoplasmic reticulum (ER) stress and learning deficits in mice. Here, we found that nerve growth factor (NGF) mRNA and protein were selectively reduced in the hippocampus of deltamethrin-treated mice. To explore potential mechanisms responsible for this observation, we employed mouse primary hippocampal neurons. Exposure of neurons to deltamethrin (1-5 μM) caused ER stress as indicated by increased levels of C/EBP-homologous protein (CHOP) and glucose-regulated protein 78 (GRP78). These changes were accompanied by increased levels of caspase-12, activated caspase-3, and decreased levels of NGF. Inhibition of ER stress with the eukaryotic initiation factor 2 alpha (eIF2α) inhibitor salubrinal abolished deltamethrin-induced activation of caspase-12 and caspase-3, and restored NGF levels. Furthermore, deltamethrin decreased Akt (protein kinase B) phosphorylation, which was significantly prevented by co-treatment with NGF or SC-79 in cells. Collectively, these results demonstrate that the loss of NGF following ER stress may contribute to deltamethrin-induced apoptosis in the hippocampus through the Akt signaling pathway, and that this may provide a plausible mechanism for impaired learning and memory observed following exposure of mice to deltamethrin.

Nanotechnology to improve the Alzheimer's disease therapy with natural compounds

Alzheimer's disease (AD) is a form of dementia with high impact worldwide, accounting with more than 46 million cases. It is estimated that the number of patients will be four times higher in 2050. The initial symptoms of AD are almost imperceptible and typically involve lapses of memory in recent events. However, the available medicines still focus on controlling the symptoms and do not cure the disease. Regarding the advances in the discovery of new treatments for this devastating disease, natural compounds are gaining increasing relevance in the treatment of AD. Nevertheless, they present some limiting characteristics such as the low bioavailability and the low ability to cross the blood-brain barrier (BBB) that hinder the development of effective therapies. To overcome these issues, the delivery of natural products by targeting nanocarriers has aroused a great interest, improving the therapeutic activity of these molecules. In this article, a review of the research progress on drug delivery systems (DDS) to improve the therapeutic activity of natural compounds with neuroprotective effects for AD is presented. Graphical abstract.

Microenvironment-responsive immunoregulatory electrospun fibers for promoting nerve function recovery

The strategies concerning modification of the complex immune pathological inflammatory environment during acute spinal cord injury remain oversimplified and superficial. Inspired by the acidic microenvironment at acute injury sites, a functional pH-responsive immunoregulation-assisted neural regeneration strategy was constructed. With the capability of directly responding to the acidic microenvironment at focal areas followed by triggered release of the IL-4 plasmid-loaded liposomes within a few hours to suppress the release of inflammatory cytokines and promote neural differentiation of mesenchymal stem cells in vitro, the microenvironment-responsive immunoregulatory electrospun fibers were implanted into acute spinal cord injury rats. Together with sustained release of nerve growth factor (NGF) achieved by microsol core-shell structure, the immunological fiber scaffolds were revealed to bring significantly shifted immune cells subtype to down-regulate the acute inflammation response, reduce scar tissue formation, promote angiogenesis as well as neural differentiation at the injury site, and enhance functional recovery in vivo. Overall, this strategy provided a delivery system through microenvironment-responsive immunological regulation effect so as to break through the current dilemma from the contradiction between immune response and nerve regeneration, providing an alternative for the treatment of acute spinal cord injury.

Effects of curcumin on neurological diseases: focus on astrocytes

Astrocytes are the most abundant glial cells in the central nervous system, and are important players in both brain injury and neurodegenerative disease. Curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione), the major active component of turmeric, belongs to the curcuminoid family that was originally isolated from the plant Curcuma longa. Several studies suggest that curcumin may have a beneficial impact on the brain pathology and aging. These effects are due to curcumin's antioxidant, free-radical scavenging, and anti-inflammatory activity. In light of this, our current review aims to discuss the role of astrocytes as essential players in neurodegenerative diseases and suggest that curcumin is capable of direct inhibition of astrocyte activity with a particular focus on its effects in Alexander disease, Alzheimer's disease, ischemia stroke, spinal cord injury, Multiple sclerosis, and Parkinson's disease.

Ligand Conjugated Targeted Nanotherapeutics for Treatment of Neurological Disorders

BACKGROUND

Human brain is amongst the most complex organs in human body, and delivery of therapeutic agents across the brain is a tedious task. Existence of blood brain barrier (BBB) protects the brain from invasion of undesirable substances; therefore it hinders the transport of various drugs used for the treatment of different neurological diseases including glioma, Parkinson's disease, Alzheimer's disease, etc. To surmount this barrier, various approaches have been used such as the use of carrier mediated drug delivery; use of intranasal route, to avoid first pass metabolism; and use of ligands (lactoferrin, apolipoprotein) to transport the drug across the BBB. Ligands bind with proteins present on the cell and facilitate the transport of drug across the cell membrane via. receptor mediated, transporter mediated or adsorptive mediated transcytosis.

OBJECTIVE

The main focus of this review article is to illustrate various studies performed using ligands for delivering drug across BBB; it also describes the procedure used by various researchers for conjugating the ligands to the formulation to achieve targeted action.

METHODS

Research articles that focused on the used of ligand conjugation for brain delivery and compared the outcome with unconjugated formulation were collected from various search engines like PubMed, Science Direct and Google Scholar, using keywords like ligands, neurological disorders, conjugation, etc. Results and Conclusion: Ligands have shown great potential in delivering drug across BBB for treatment of various diseases, yet extensive research is required so that the ligands can be used clinically for treating neurological diseases.

Targeted therapy in chronic diseases using nanomaterial-based drug delivery vehicles

The application of nanomedicines is increasing rapidly with the promise of targeted and efficient drug delivery. Nanomedicines address the shortcomings of conventional therapy, as evidenced by several preclinical and clinical investigations indicating site-specific drug delivery, reduced side effects, and better treatment outcome. The development of suitable and biocompatible drug delivery vehicles is a prerequisite that has been successfully achieved by using simple and functionalized liposomes, nanoparticles, hydrogels, micelles, dendrimers, and mesoporous particles. A variety of drug delivery vehicles have been established for the targeted and controlled delivery of therapeutic agents in a wide range of chronic diseases, such as diabetes, cancer, atherosclerosis, myocardial ischemia, asthma, pulmonary tuberculosis, Parkinson's disease, and Alzheimer's disease. After successful outcomes in preclinical and clinical trials, many of these drugs have been marketed for human use, such as Abraxane®, Caelyx®, Mepact®, Myocet®, Emend®, and Rapamune®. Apart from drugs/compounds, novel therapeutic agents, such as peptides, nucleic acids (DNA and RNA), and genes have also shown potential to be used as nanomedicines for the treatment of several chronic ailments. However, a large number of extensive clinical trials are still needed to ensure the short-term and long-term effects of nanomedicines in humans. This review discusses the advantages of various drug delivery vehicles for better understanding of their utility in terms of current medical needs. Furthermore, the application of a wide range of nanomedicines is also described in the context of major chronic diseases.

Curcuminoids and Novel Opportunities for the Treatment of Alzheimer's Disease: Which Molecules are Actually Effective?

BACKGROUND

Millions of people worldwide are suffering from Alzheimer's disease (AD), and there are only symptomatic treatments available for this disease. Thus, there is a great need to identify drugs capable of arresting or reversing AD. Constituents of the spice turmeric, in particular, curcuminoids, seem to be very promising, as evident from in vitro experiments and tests using animal models of AD. However, most of the clinical trials did not reveal any beneficial effects of curcuminoids in the treatment of AD. These controversies, including conflicting results of clinical trials, are thought to be related to bioavailability of curcuminoids, which is low unless it is enhanced by developing a special formulation. However, there is growing evidence suggesting that other reasons may be of even greater importance, but these avenues are less explored.

OBJECTIVE

Review relevant literature, and analyze potential reasons for the controversial results.

METHODOLOGY

Recent in vitro and preclinical studies; clinical trials (without a limiting period) were searched in PubMed and Google Scholar.

RESULTS

While recent in vitro and preclinical studies confirm the therapeutic potential of curcuminoids in the treatment of AD and cognitive dysfunctions, results of corresponding clinical trials remain rather controversial.

CONCLUSION

The controversial results obtained in the clinical trials may be in part due to particularities of the curcuminoid formulations other than bioavailability. Namely, it seems likely that the various formulations differ in terms of their minor turmeric constituent(s). We hypothesize that these distinctions may be of key importance for efficacy of the particular formulation in clinical trials. A testable approach addressing this hypothesis is suggested.

Amphiphilic Nanocarrier Systems for Curcumin Delivery in Neurodegenerative Disorders

Neurodegenerative diseases have become a major challenge for public health because of their incurable status. Soft nanotechnology provides potential for slowing down the progression of neurodegenerative disorders by using innovative formulations of neuroprotective antioxidants like curcumin, resveratrol, vitamin E, rosmarinic acid, 7,8-dihydroxyflavone, coenzyme Q10, and fish oil. Curcumin is a natural, liposoluble compound, which is of considerable interest for nanomedicine development in combination therapies. The neuroprotective effects of combination treatments can involve restorative mechanisms against oxidative stress, mitochondrial dysfunction, inflammation, and protein aggregation. Despite the anti-amyloid and anti-tau potential of curcumin and its neurogenesis-stimulating properties, the utilization of this antioxidant as a drug in neuroregenerative therapies has huge limitations due to its poor water solubility, physico-chemical instability, and low oral bioavailability. We highlight the developments of soft lipid- and polymer-based delivery carriers of curcumin, which help improve the drug solubility and stability. We specifically focus on amphiphilic liquid crystalline nanocarriers (cubosome, hexosome, spongosome, and liposome particles) for the encapsulation of curcumin with the purpose of halting the progressive neuronal loss in Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis (ALS).

Strategies for brain-targeting liposomal delivery of small hydrophobic molecules in the treatment of neurodegenerative diseases

Neurodegenerative diseases (NDs), including Alzheimer's disease (AD) and Parkinson's disease (PD), threaten the health of an ever-growing number of older people worldwide; so far, there are no effective cures. Significant efforts have been devoted to developing new drugs for NDs in recent years, and some small molecules have been shown to be promising in preclinical studies. However, the major challenge for brain-targeting drugs is how to efficiently deliver the drugs across the blood-brain barrier (BBB) to desired targets. To address this issue, liposomal delivery systems have proved to be ideal carriers for neuroprotective small molecules. Here, we summarize recent advances in the brain-targeting liposomal delivery of small hydrophobic molecules (SHMs) and propose strategies for developing liposomal SHMs as disease-modifying neurotherapeutics for NDs.

Vinorelbine cationic liposomes modified with wheat germ agglutinin for inhibiting tumor metastasis in treatment of brain glioma

Glioma is the most common primary malignant brain tumor with a poor prognosis. The application of chemotherapeutic drugs is limited due to the existence of blood-brain barrier and serious side effects. Liposomes have been proven to be a stable and useful drug delivery system for tumors. In this paper, WGA (wheat germ agglutinin) modified vinorelbine cationic liposomes had been successfully constructed for treating glioma. In the liposomes, WGA was modified on the liposomal surface for crossing the blood-brain barrier and increasing the targeting effects, 3-(N-(N', N'-dimethylaminoethane) carbamoyl) cholesterol (DC-Chol) was used as cationic material and vinorelbine was encapsulated in the aqueous core of liposomes to inhibit tumor metastasis and kill tumor cells. Studies were performed on C6 cells in vitro and were verified in brain glioma-bearing mice in vivo. Results in vitro demonstrated that the targeting liposomes could induce C6 cells apoptosis, promote drugs across the blood-brain barrier, inhibit the metastasis of tumor cells and increase targeting effects to tumor cells. Meanwhile, action mechanism studies showed that the targeting liposomes could down-regulate PI3K, MMP-2, MMP-9 and FAK to inhibit tumor metastasis. Results in vivo exhibited that the targeting liposomes displayed an obvious antitumor efficacy by accumulating selectively in tumor site and exhibited low toxicity to blood system and major organs. Hence, WGA modified vinorelbine cationic liposomes might provide a safe and efficient therapy strategy for glioma.

Use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease

This review summarizes and describes the use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease. For diagnosis of Alzheimer's disease, amyloid-β and highly phosphorylated tau protein are the major biomarkers. Curcumin was developed as an early diagnostic probe based on its natural fluorescence and high binding affinity to amyloid-β. Because of its multi-target effects, curcumin has protective and preventive effects on many chronic diseases such as cerebrovascular disease, hypertension, and hyperlipidemia. For prevention and treatment of Alzheimer's disease, curcumin has been shown to effectively maintain the normal structure and function of cerebral vessels, mitochondria, and synapses, reduce risk factors for a variety of chronic diseases, and decrease the risk of Alzheimer's disease. The effect of curcumin on Alzheimer's disease involves multiple signaling pathways: anti-amyloid and metal iron chelating properties, antioxidation and anti-inflammatory activities. Indeed, there is a scientific basis for the rational application of curcumin in prevention and treatment of Alzheimer's disease.

Effects of Micro-environmental pH of Liposome on Chemical Stability of Loaded Drug

Liposome is a promising carrier system for delivering bioactive molecules. However, the successful delivery of pH-sensitive molecules is still limited by the intrinsic instability of payloads in physiological environment. Herein, we developed a special liposome system that possesses an acidic micro-environment in the internal aqueous chamber to improve the chemical stability of pH-sensitive payloads. Curcumin-loaded liposomes (Cur-LPs) with varied internal pH values (pH 2.5, 5.0, or 7.4) were prepared. These Cur-LPs have similar particle size of 300 nm, comparable physical stabilities and analogous in vitro release profiles. Interestingly, the chemical stability of liposomal curcumin in 50% fetal bovine serum and its anticancer efficacy in vitro are both micro-environmental pH-dependent (Cur-LP-2.5 > Cur-LP-5.0 > Cur-LP-7.4). This serum stability still has space to be further enhanced to improve the applicability of Cur-LP. In conclusion, creating an acidic micro-environment in the internal chamber of liposome is feasible and efficient to improve the chemical stability of pH-sensitive payloads.

Erythrocyte membrane-encapsulated celecoxib improves the cognitive decline of Alzheimer's disease by concurrently inducing neurogenesis and reducing apoptosis in APP/PS1 transgenic mice

Alzheimer's disease (AD) is characterized by the loss of neurogenesis and excessive induction of apoptosis. The induction of neurogenesis and inhibition of apoptosis may be a promising therapeutic approach to combating the disease. Celecoxib (CB), a cyclooxygenase-2 specific inhibitor, could offer neuroprotection. Specifically, the CB-encapsulated erythrocyte membranes (CB-RBCMs) sustained the release of CB over a period of 72 h in vitro and exhibited high brain biodistribution efficiency following intranasal administration, which resulted in the clearance of aggregated β-amyloid proteins (Aβ) in neurons. The high accumulation of the CB-RBCMs in neurons resulted in a decrease in the neurotoxicity of CB and an increase in the migratory activity of neurons, and alleviated cognitive decline in APP/PS1 transgenic (Tg) mice. Indeed, COX-2 metabolic products including prostaglandin E2 (PGE₂) and PGD₂, PGE₂ induced neurogenesis by enhancing the expression of SOD2 and 14-3-3ζ, and PGD₂ stimulated apoptosis by increasing the expression of BIK and decreasing the expression of ARRB1. To this end, the CB-RBCMs achieved better effects on concurrently increasing neurogenesis and decreasing apoptosis than the phospholipid membrane-encapsulated CB liposomes (CB-PSPD-LPs), which are critical for the development and progression of AD. Therefore, CB-RBCMs provide a rational design to treat AD by promoting the self-repairing capacity of the brain.

Self-assembled amphiphilic core-shell nanocarriers in line with the modern strategies for brain delivery

Disorders of the central nervous system (CNS) represent increasing social and economic problems all over the world which makes the effective transport of drugs to the brain a crucial need. In the last decade, many strategies were introduced to deliver drugs to the brain trying to overcome the challenge of the blood brain barrier (BBB) using both invasive and non-invasive methods. Non-invasive strategy represented in the application of nanocarriers became very common. One of the most hopeful nanoscopic carriers for brain delivery is core-shell nanocarriers or polymeric micelles (PMs). They are more advantageous than other nanocarriers. They offer small size, ease of preparation, ease of sterilization and the possibility of surface modification with various ligands. Hence, the aim of this review is to discuss modern strategies for brain delivery, micelles as a successful delivery system for the brain and how micelles could be modified to act as "magic bullets" for brain delivery.

The efficacy of WGA modified daunorubicin anti-resistant liposomes in treatment of drug-resistant MCF-7 breast cancer

BACKGROUND

Breast cancer is the most common malignancy and remains a leading cause of cancer-related deaths in female. Chemotherapy failure of breast cancer is mainly associated with multidrug resistance of cancer cells.

PURPOSE

The WGA modified daunorubicin anti-resistant liposomes were developed for circumventing the multidrug resistance and eliminating cancer cells.

METHODS

WGA was modified on liposomal surface for increasing the intracellular uptake. Tetrandrine was inserted into the phospholipid bilayer for reversing cancer drug-resistance, and daunorubicin was encapsulated in liposomal aqueous core as an anticancer agent. Evaluations were performed on MCF-7 cells, MCF-7/ADR cells and xenografts of MCF-7/ADR cells.

RESULTS

In vitro results showed that WGA modified daunorubicin anti-resistant liposomes exhibited suitable physicochemical properties, significantly increased intracellular uptake in both MCF-7 cells and MCF-7/ADR cells, and circumvented the multidrug resistance via inhibiting P-gp. In vivo results demonstrated that the targeting liposomes showed a long-circulatory effect in blood system, and could remarkably accumulate at the tumor location. The involved action mechanisms for the enhanced anticancer efficacy were activation of pro-apoptotic proteins (Bax and Bok), apoptotic enzymes (caspase 8, caspase 9 and caspase 3).

CONCLUSION

The established WGA modified daunorubicin anti-resistant liposomes could provide a potential strategy for treating resistant MCF-7 breast cancer.

Wheat germ agglutinin-conjugated liposomes incorporated with cardiolipin to improve neuronal survival in Alzheimer's disease treatment

Curcumin (CRM) and nerve growth factor (NGF) were entrapped in liposomes (LIP) with surface wheat germ agglutinin (WGA) to downregulate the phosphorylation of kinases in Alzheimer’s disease (AD) therapy. Cardiolipin (CL)-conjugated LIP carrying CRM (CRM-CL/LIP) and also carrying NGF (NGF-CL/LIP) were used with AD models of SK-N-MC cells and Wistar rats after an insult with β-amyloid peptide (Aβ). We found that CRM-CL/LIP inhibited the expression of phosphorylated p38 (p-p38), phosphorylated c-Jun N-terminal kinase (p-JNK), and p-tau protein at serine 202 and prevented neurodegeneration of SK-N-MC cells. In addition, NGF-CL/LIP could enhance the quantities of p-neurotrophic tyrosine kinase receptor type 1 and p-extracellular signal-regulated kinase 5 for neuronal rescue. Moreover, WGA-grafted CRM-CL/LIP and WGA-grafted NGF-CL/LIP significantly improved the permeation of CRM and NGF across the blood–brain barrier, reduced Aβ plaque deposition and the malondialdehyde level, and increased the percentage of normal neurons and cholinergic activity in the hippocampus of AD rats. Based on the marker expressions and in vivo evidence, current LIP carriers can be promising drug delivery systems to protect nervous tissue against Aβ-induced apoptosis in the brain during the clinical management of AD.

Curcumin upregulates S100 expression and improves regeneration of the sciatic nerve following its complete amputation in mice

The repair of peripheral nerve injury after complete amputation is difficult, and even with anastomosis, the rapid recovery of nerve function remains challenging. Curcumin, extracted from plants of the genus Curcuma, has been shown to have anti-oxidant and anti-inflammatory properties and to improve sciatic nerve crush injury in rats. Here, we determined whether curcumin had neuroprotective effects following complete peripheral nerve amputation injury. BALB/c mice underwent complete sciatic nerve amputation, followed by an immediate epineurium anastomosis. Mice were intragastrically administered curcumin at doses of 40 (high), 20 (moderate), and 10 mg/kg/d (low) for 1 week. We found that myelin in the mice of the high- and moderate-dose curcumin groups appeared with regular shape, uniform thickness, clear boundary, and little hyperplasia surrounding the myelin. High and moderate doses of curcumin markedly improved both action potential amplitude of the sciatic nerves and the conduction velocity of the corresponding motor neurons, and upregulated mRNA and protein expression of S100, a marker for Schwann cell proliferation, in L_4–6 spinal cord segments. These results suggest that curcumin is effective in promoting the repair of complete sciatic nerve amputation injury and that the underlying mechanism may be associated with upregulation of S100 expression.

Conjugation of melanotransferrin antibody on solid lipid nanoparticles for mediating brain cancer malignancy

Solid lipid nanoparticles (SLNs) comprising complex internal lipids were conjugated with melanotransferrin antibody (MA) to carry anticancer etoposide across the blood-brain barrier (BBB) for managing glioblastoma multiforme (GBM). MA was crosslinked on the surface of etoposide-loaded SLNs (ETP-SLNs) to target human brain-microvascular endothelial cells (HBMECs) and U87MG cells. The experimental evidences showed that an increase in the tripalmitin weight percentage in lipids enhanced the particle size and viability of U87MG cells, however decreased the etoposide loading efficiency, MA conjugation efficiency, and permeability coefficient for etoposide across the BBB. A high level of MA on the particle surface increased the atomic ratio of nitrogen to phosphorus and permeability coefficient for propidium iodide and etoposide across the BBB, however reduced the MA conjugation efficiency, transendothelial electrical resistance, and viability of U87MG cells. Based on immunochemical staining, we found that MA on ETP-SLNs triggered the melanotransferrin-mediated transcytosis and promoted the growth-inhibitory efficacy to U87MG cells. MA-conjugated ETP-SLNs can be a promising colloidal delivery system for malignant GBM pharmacotherapy. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:480-490, 2016.

Brain targeted delivery of carmustine using solid lipid nanoparticles modified with tamoxifen and lactoferrin for antitumor proliferation

Solid lipid nanoparticles (SLNs) conjugated with tamoxifen (TX) and lactoferrin (Lf) were applied to carry anticancer carmustine (BCNU) across the blood-brain barrier (BBB) for enhanced antiproliferation against glioblastoma multiforme (GBM). BCNU-loaded SLNs with modified TX and Lf (TX-Lf-BCNU-SLNs) were used to penetrate a monolayer of human brain-microvascular endothelial cells (HBMECs) and human astrocytes and to target malignant U87MG cells. The surface TX and Lf on TX-Lf-BCNU-SLNs improved the characteristics of sustained release for BCNU. When compared with BCNU-loaded SLNs, TX-Lf-BCNU-SLNs increased the BBB permeability coefficient for BCNU about ten times. In addition, TX-BCNU-SLNs considerably promoted the fluorescent intensity of intracellular acetomethoxy derivative of calcein (calcein-AM) in HBMECs via endocytosis. However, the conjugated Lf could only slightly increase the fluorescence of calcein-AM. Moreover, the order of formulation in the inhibition to U87MG cells was TX-Lf-BCNU-SLNs>TX-BCNU-SLNs>Lf-BCNU-SLNs>BCNU-SLNs. TX-Lf-BCNU-SLNs can be effective in infiltrating the BBB and delivering BCNU to GBM for future chemotherapy application.