Solid lipid nanoparticles loading with curcumin and dexanabinol to treat major depressive disorder

Curcumin can improve spinal cord injury by inhibiting DNA methylation

Spinal cord injury (SCI) is a serious central nervous system disease. Traumatic SCI often causes persistent neurological deficits below the injury level. Epigenetic changes occur after SCI. Studies have shown DNA methylation to be a key player in nerve regeneration and remodeling, and in regulating some pathophysiological characteristics of SCI. Curcumin is a natural polyphenol from turmeric. It has anti-inflammatory, antioxidant, and neuroprotective effects, and can mitigate the cell and tissue damage caused by SCI. This report analyzed the specific functions of DNA methylation in central nervous system diseases, especially traumatic brain injury and SCI. DNA methylation can regulate the level of gene expressions in the central nervous system. Therefore, pharmacological interventions regulating DNA methylation may be promising for SCI.

Spinal cord injury: molecular mechanisms and therapeutic interventions

Spinal cord injury (SCI) remains a severe condition with an extremely high disability rate. The challenges of SCI repair include its complex pathological mechanisms and the difficulties of neural regeneration in the central nervous system. In the past few decades, researchers have attempted to completely elucidate the pathological mechanism of SCI and identify effective strategies to promote axon regeneration and neural circuit remodeling, but the results have not been ideal. Recently, new pathological mechanisms of SCI, especially the interactions between immune and neural cell responses, have been revealed by single-cell sequencing and spatial transcriptome analysis. With the development of bioactive materials and stem cells, more attention has been focused on forming intermediate neural networks to promote neural regeneration and neural circuit reconstruction than on promoting axonal regeneration in the corticospinal tract. Furthermore, technologies to control physical parameters such as electricity, magnetism and ultrasound have been constantly innovated and applied in neural cell fate regulation. Among these advanced novel strategies and technologies, stem cell therapy, biomaterial transplantation, and electromagnetic stimulation have entered into the stage of clinical trials, and some of them have already been applied in clinical treatment. In this review, we outline the overall epidemiology and pathophysiology of SCI, expound on the latest research progress related to neural regeneration and circuit reconstruction in detail, and propose future directions for SCI repair and clinical applications.

Amoxapine-Loaded Solid Lipid Nanoparticles with Superior Preclinical Pharmacokinetics for Better Brain Delivery: LC-MS/MS and GC-MS Analysis

The tricyclic antidepressant amoxapine (AMX) has been reported for a rapid onset of action compared to other cyclic antidepressants. It has very low solubility and bioavailability due to first-pass metabolism. Therefore, we planned to develop solid lipid nanoparticles (SLNs) of AMX using a single emulsification method to increase its solubility and bioavailability. HPLC and LC-MS/MS methods were developed further to quantify AMX in the formulation, plasma, and brain tissue samples. The formulation was studied for entrapment efficiency, loading, and in vitro drug release. Particle size and ζ potential analyses, AFM, SEM, TEM, DSC, and XRD were used for further characterization. In vivo oral pharmacokinetic and brain pharmacokinetic studies were performed using Wistar rats. The entrapment and loading efficiencies of AMX in SLNs were 85.8 ± 3.42 and 4.5 ± 0.45%, respectively. The developed formulation had a mean particle size of 151.5 ± 7.02 nm and a polydispersity index of 0.40 ± 0.11. DSC and XRD results indicated that AMX was incorporated into the nanocarrier system in an amorphous form. SEM, TEM, and AFM studies of AMX-SLNs confirmed the particles' spherical shape and nanoscale size. AMX solubility increased by approx. 2.67 times compared to the pure drug. The developed LC-MS/MS method was successfully applied to the oral and brain pharmacokinetic study of AMX-loaded SLNs in rats. Oral bioavailability was enhanced 1.6 times compared to the pure drug. The peak plasma concentrations of pure AMX and AMX-SLNs were 617.4 ± 137.4 and 1043.5 ± 150.2 (ng/mL), respectively. AMX-SLNs showed more than 5.8 times brain concentration compared to the pure drug. Based on the findings, it appears that utilizing a solid lipid nanoparticle carrier to transport AMX can be a highly effective delivery method with improved pharmacokinetic properties in the brain. This approach may prove valuable for future antidepressant treatment.

Cannabinoid-Based Ocular Therapies and Formulations

The interest in the pharmacological applications of cannabinoids is largely increasing in a wide range of medical areas. Recently, research on its potential role in eye conditions, many of which are chronic and/or disabling and in need of new alternative treatments, has intensified. However, due to cannabinoids’ unfavorable physicochemical properties and adverse systemic effects, along with ocular biological barriers to local drug administration, drug delivery systems are needed. Hence, this review focused on the following: (i) identifying eye disease conditions potentially subject to treatment with cannabinoids and their pharmacological role, with emphasis on glaucoma, uveitis, diabetic retinopathy, keratitis and the prevention of Pseudomonas aeruginosa infections; (ii) reviewing the physicochemical properties of formulations that must be controlled and/or optimized for successful ocular administration; (iii) analyzing works evaluating cannabinoid-based formulations for ocular administration, with emphasis on results and limitations; and (iv) identifying alternative cannabinoid-based formulations that could potentially be useful for ocular administration strategies. Finally, an overview of the current advances and limitations in the field, the technological challenges to overcome and the prospective further developments, is provided.

Combined Dopamine and Grape Seed Extract-Loaded Solid Lipid Nanoparticles: Nasal Mucosa Permeation, and Uptake by Olfactory Ensheathing Cells and Neuronal SH-SY5Y Cells

We have already formulated solid lipid nanoparticles (SLNs) in which the combination of the neurotransmitter dopamine (DA) and the antioxidant grape-seed-derived proanthocyanidins (grape seed extract, GSE) was supposed to be favorable for Parkinson’s disease (PD) treatment. In fact, GSE supply would reduce the PD-related oxidative stress in a synergic effect with DA. Herein, two different methods of DA/GSE loading were studied, namely, coadministration in the aqueous phase of DA and GSE, and the other approach consisting of a physical adsorption of GSE onto preformed DA containing SLNs. Mean diameter of DA coencapsulating GSE SLNs was 187 ± 4 nm vs. 287 ± 15 nm of GSE adsorbing DA-SLNs. TEM microphotographs evidenced low-contrast spheroidal particles, irrespective of the SLN type. Moreover, Franz diffusion cell experiments confirmed the permeation of DA from both SLNs through the porcine nasal mucosa. Furthermore, fluorescent SLNs also underwent cell-uptake studies by using flow cytometry in olfactory ensheathing cells and neuronal SH-SY5Y cells, evidencing higher uptake when GSE was coencapsulated rather than adsorbed onto the particles.

KCC2 overexpressed exosomes meditated spinal cord injury recovery in mice

Exosomes show great potential in treating diseases of the central nervous system including spinal cord injury (SCI), still better engineered exosomes have more advantages. In this study, we purified exosomes from K⁺-Cl^-co-transporter (KCC2) overexpressed bone marrow mesenchymal stem cells (Exo_KCC2), to investigate the effect of Exo_KCC2on neural differentiationin vitroand the repairing function of Exo_KCC2in SCI micein vivo. Compared to bone marrow mesenchymal stem cells (BMSC)-derived exosomes (Exo), Exo_KCC2could better promote neural stem cell differentiated into neurons, ameliorate the function recovery of SCI mice, and accelerate the neural regeneration at the lesion site. Altogether, engineered Exo_KCC2may prove to be an advantageous strategy for SCI treatment.

Bioactive 2D nanomaterials for neural repair and regeneration

Biomaterials have provided promising strategies towards improving the functions of injured tissues of the nervous system. Recently, 2D nanomaterials, such as graphene, layered double hydroxides (LDHs), and black phosphorous, which are characterized by ultrathin film structures, have attracted much attention in the fields of neural repair and regeneration. 2D nanomaterials have extraordinary physicochemical properties and excellent biological activities, such as a large surface-area-to-thickness ratio, high levels of adhesion, and adjustable flexibility. In addition, they can be designed to have superior biocompatibility and electrical or nano-carrier properties. To date, many 2D nanomaterials have been used for synaptic modulation, neuroinflammatory reduction, stem cell fate regulation, and injured neural cell/tissue repair. In this review, we discuss the advances in 2D nanomaterial technology towards novel neurological applications and the mechanisms underlying their unique features. In addition, the future outlook of functional 2D nanomaterials towards addressing the difficult issues of neuropathy has been explored to introduce a promising strategy towards repairing and regenerating the injured nervous system.

An Update on the Exploratory Use of Curcumin in Neuropsychiatric Disorders

Curcumin is a polyphenol extracted from the rhizome of the turmeric plant. Beyond its common use as a culinary spice in Eastern Asia, curcumin has been proposed as a therapeutic compound due to its antioxidant, anti-inflammatory and neuroprotective properties. Thus, its efficacy has been evaluated in various inflammatory-based psychiatric disorders, such as schizophrenia, depression, or autism. Our aim is to review those preclinical and clinical studies carried out in psychiatric disorders whose therapeutic approach has involved the use of curcumin and, therefore, to discern the possible positive effect of curcumin in these disorders. Preclinical studies and completed clinical trials of curcumin for psychiatric disorders published from January 2005 to October 2021 were identified through searching relevant databases until 31st October 2021. Sixty-five preclinical studies and 15 clinical trials and open-label studies were selected. Results showed a bias toward studies in depression and, to a lesser extent, schizophrenia. In all disorders, the results were positive in reducing psychiatric deficits. Despite the considerable number of beneficial outcomes reported, the small number of trials and the heterogeneity of protocols make it difficult to draw solid conclusions about the real potency of curcumin in psychiatric disorders.

Potential Role of Curcumin for the Treatment of Major Depressive Disorder

Curcumin is the major biologically active polyphenolic constituent in the turmeric plant (Curcuma longa) that has been shown to have antioxidant, anti-inflammatory, neuroprotective, anticancer, antimicrobial, and cardioprotective effects. Interest in curcumin as a treatment for mental health conditions has increased and there is an expanding body of preclinical and clinical research examining its antidepressant and anxiolytic effects. In this narrative review, human trials investigating the effects of curcumin for the treatment of depression or depressive symptoms are summarised. Using findings from in vitro, animal, and human trials, possible biological mechanisms associated with the antidepressant effects of curcumin are also explored. To increase the understanding of curcumin for the treatment of depression, directions for future research are proposed.

The Tiny Big World of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: An Updated Review

Nanotechnology is currently a field of endeavor that has reached a maturation phase beyond the initial hypotheses with an undercurrent challenge to optimize the safety, and scalability for production and clinical trials. Lipid-based nanoparticles (LNP), namely solid lipid nanoparticles (SLN) and nanostructured lipid (NLC), carriers are presently among the most attractive and fast-growing areas of research. SLN and NLC are safe, biocompatible nanotechnology-enabled platforms with ubiquitous applications. This review presents a modern vision that starts with a brief description of characteristics, preparation strategies, and composition ingredients, benefits, and limitations. Next, a discussion of applications and functionalization approaches for the delivery of therapeutics via different routes of delivery. Additionally, the review presents a concise perspective into limitations and future advances. A brief recap on the prospects of molecular dynamics simulations in better understanding NP bio-interface interactions is provided. Finally, the alliance between 3D printing and nanomaterials is presented here as well.

Natural polysaccharides based self-assembled nanoparticles for biomedical applications - A review

In recent years, nanoparticles (NPs) derived from the self-assembly of natural polysaccharides have shown great potential in the biomedical field. Here, we described several self-assembly modes of natural polysaccharides in detail, summarized the natural polysaccharides mostly used for self-assembly, and provided insights into the current applications and achievements of these self-assembled NPs. As one of the most widespread substances in nature, most natural polysaccharides exhibit advantages of biodegradability, low immunogenicity, low toxicity, and degradable properties. Therefore, they have been fully explored, and the application of chitosan, hyaluronic acid, alginate, starch, and their derivatives has been extensively studied, especially in the fields of biomedical. Polysaccharides based NPs were proved to improve the solubility of insoluble drugs, enhance tissue target ability and realize the controlled and sustained release of drugs. When modified by hydrophobic groups, the amphiphilic polysaccharides can self-assemble into NPs. Other driven forces of self-assembly include electrostatic interaction and hydrogen bonds. Up to the present, polysaccharides-based nanoparticles have been widely applied for tumor treatment, antibacterial application, gene therapy, photodynamic therapy and transporting insulin.

Cannabinoid Formulations and Delivery Systems: Current and Future Options to Treat Pain

The field of Cannabis sativa L. research for medical purposes has been rapidly advancing in recent decades and a growing body of evidence suggests that phytocannabinoids are beneficial for a range of conditions. At the same time impressing development has been observed for formulations and delivery systems expanding the potential use of cannabinoids as an effective medical therapy. The objective of this review is to present the most recent results from pharmaceutical companies and research groups investigating methods to improve cannabinoid bioavailability and to clearly establish its therapeutic efficacy, dose ranges, safety and also improve the patient compliance. Particular focus is the application of cannabinoids in pain treatment, describing the principal cannabinoids employed, the most promising delivery systems for each administration routes and updating the clinical evaluations. To offer the reader a wider view, this review discusses the formulation starting from galenic preparation up to nanotechnology approaches, showing advantages, limits, requirements needed. Furthermore, the most recent clinical data and meta-analysis for cannabinoids used in different pain management are summarized, evaluating their real effectiveness, in order also to spare opioids and improve patients' quality of life. Promising evidence for pain treatments and for other important pathologies are also reviewed as likely future directions for cannabinoids formulations.

A comprehensive review of the therapeutic potential of curcumin nanoformulations

Today, due to the prevalence of various diseases such as the novel coronavirus (SARS-CoV-2), diabetes, central nervous system diseases, cancer, cardiovascular disorders, and so on, extensive studies have been conducted on therapeutic properties of natural and synthetic agents. A literature review on herbal medicine and commercial products in the global market showed that curcumin (Cur) has many therapeutic benefits compared to other natural ingredients. Despite the unique properties of Cur, its use in clinical trials is very limited. The poor biopharmaceutical properties of Cur such as short half-life in plasma, low bioavailability, poor absorption, rapid metabolism, very low solubility (at acidic and physiological pH), and the chemical instability in body fluids are major concerns associated with the clinical applications of Cur. Recently, nanoformulations are emerging as approaches to develop and improve the therapeutic efficacy of various drugs. Many studies have shown that Cur nanoformulations have tremendous therapeutic potential against various diseases such as SARS-CoV-2, cancer, inflammatory, osteoporosis, and so on. These nanoformulations can inhibit many diseases through several cellular and molecular mechanisms. However, successful long-term clinical results are required to confirm their safety and clinical efficacy. The present review aims to update and explain the therapeutic potential of Cur nanoformulations.

Pharmacokinetics and Pharmacodynamics of Curcumin-Loaded Solid Lipid Nanoparticles in the Management of Streptozotocin-Induced Diabetes Mellitus: Application of Central Composite Design

Due to poor bioavailability and chemical instability, the effectiveness of curcumin is negligible in the treatment of numerous diseases. Solid lipid nanoparticles (SLNs) increase the bioavailability of lipophilic compounds and protect the drug from gastrointestinal degradation. The objective of our study is the utilization of SLNs to improve the pharmacokinetics and pharmacodynamics of curcumin in the management of diabetes mellitus. Central composite design was used to prepare curcumin-loaded SLNs (Cur-SLN). The analysis of independent variables like drug concentration, lipid concentration, and surfactant concentration was carried out using analysis of variance (ANOVA) to obtain the optimized batch (optimized Cur-SLN) having the desired values of dependent variables particle size and entrapment efficiency. In vitro release, differential scanning calorimeter (DSC), transmission electron microscopy (TEM), and Fourier Transform Infra-Red (FTIR) studies of optimized Cur-SLN were carried out and then its pharmacokinetic and pharmacodynamic studies were performed. The model was found to be significant for particle size and entrapment efficiency based on F-value and p-value. The optimized batch's predicted values were in close agreement with the actual values of particle size and entrapment efficiency. TEM results confirm mono-dispersion and spherical shape of particles in the formulation. The DSC results confirmed the changing of drug from crystalline to amorphous form. Burst release followed by the sustained release was obtained in the in vitro release studies. The pharmacokinetic study shows enhanced bioavailability of optimized Cur-SLN compared with a plain drug suspension. The optimized Cur-SLN achieved higher antidiabetic activity in streptozotocin-induced diabetes mellitus rats than the plain drug suspension. SLNs can be used as a promising technique for delivering curcumin in the management of diabetes mellitus.

Curcumin promotes the survival of ischemic random skin flaps via autophagy

Random skin flaps have been widely applied in reconstructive and plastic surgery; however, necrosis usually happens due to insufficient blood supply in the ischemic area of flaps. Curcumin (CUR) is a primary bioactive compound of turmeric (Curcuma longa, L.), which has been proven to be effective on anticancer, decreasing oxidative stress and apoptosis through activating autophagy, and promoting angiogenesis in ischemic tissue. Therefore, the potential therapeutic effect of CUR on promoting survival of ischemic random skin flaps and its underlying mechanism associated with autophagy were investigated. After establishment of dorsal random skin flaps, sixty mice were randomly divided into three groups: Control, CUR or CUR+3-methyladenine (3-MA, an autophagy inhibitor). The results showed that CUR increased the viability area and blood flow as well as relieved the edema of skin flaps through promoting angiogenesis, decreasing oxidative stress, and inhibiting apoptosis of the ischemic area. Further study confirmed that CUR activated autophagy in the random skin flaps, and 3-MA effectively reversed the effect on viability, neovascularization, oxidative stress and apoptosis, suggesting autophagy played a vital role in these CUR's protective effect on random skin flaps. Moreover, this CUR-induced autophagy should be mediated through downregulating the PI3K/AKT/mTOR signaling pathway. Together with secondary response of increased angiogenesis, reduced oxidative stress and apoptosis, CUR effectively improved survival of random skin flaps in vivo. To sum up, our research showed the great potential of CUR using as a promising flap protective therapy for random skin flap survival and regeneration.