Cannabidiol-loaded microspheres incorporated into osteoconductive scaffold enhance mesenchymal stem cell recruitment and regeneration of critical-sized bone defects

The Incorporation of CBD into Biodegradable DL-Lactide/Glycolide Copolymers Creates a Persistent Antibacterial Environment: An In Vitro Study on Streptococcus mutans and Staphylococcus aureus

Background: Cannabidiol (CBD) is a natural compound from the Cannabis sativa L. plant, which has anti-inflammatory, anti-nociceptive, neuroprotective, and antibacterial activities. Objective: The aim of this study was to develop a sustained-release device of CBD that can provide an antibacterial effect against the Gram-positive bacteria Streptococcus mutans and Staphylococcus aureus for extended periods of time. Methods: CBD was incorporated into the biodegradable PURASORB 5010 or PURASORB 7510 DL-lactide/glycolide polymers using either dimethylsulfoxide (DMSO) or acetone as the solvent, and the dried polymer scaffolds were exposed daily to a fresh culture of bacteria. The bacterial growth was determined daily by optical density, and the metabolic activity of biofilms was determined using the MTT assay. Biofilm formation on the polymer scaffolds was visualized by HR-SEM. Its anti-inflammatory effect was determined by measuring the IL-6 release from LPS-stimulated RAW 264.7 macrophages by ELISA. Cell cytotoxicity on normal Vero epithelial cells was determined by the MTT assay. The daily release of CBD was determined by gas chromatography-mass spectrometry (GC-MS). Results: PURASORB 5010/CBD scaffolds had antibacterial activity against S. mutans UA159, S. aureus ATCC25923, and a clinical isolate of a multidrug-resistant S. aureus (MDRSA CI-M) strain for the tested period of up to 17 days. PURASORB 7510/CBD scaffolds also had antibacterial activity, but overall, it was less effective than PURASORB 5010/CBD over time. The addition of PEG400 to the copolymers significantly increased the antibacterial activity of PURASORB 7510/CBD but not of PURASORB 5010/CBD. The daily release of CBD from the polymer scaffolds was sufficient to reduce the LPS-induced IL-6 secretion from RAW 264.7 macrophages, and importantly, it was not cytotoxic to either RAW 264.7 macrophages or Vero epithelial cells. The daily release of CBD was found to be between 1.12 and 9.43 µg/mL, which is far below the cytotoxic dose of 25 µg/mL. Conclusions: The incorporation of CBD into the biodegradable PURASORB 5010 can be used to prepare sustained-release devices for medical purposes where combined antibacterial and anti-inflammatory activities are desirable.

Cannabidiol alleviates LPS-inhibited odonto/osteogenic differentiation in human dental pulp stem cells in vitro

AIM

Cannabidiol (CBD), derived from the Cannabis sativa plant, exhibits benefits in potentially alleviating a number of oral and dental pathoses, including pulpitis and periodontal diseases. This study aimed to explore the impact of CBD on several traits of human dental pulp stem cells (hDPSC), such as their proliferation, apoptosis, migration and odonto/osteogenic differentiation.

METHODOLOGY

hDPSCs were harvested from human dental pulp tissues. The cells were treated with CBD at concentrations of 1.25, 2.5, 5, 10, 25 and 50 μg/mL. Cell responses in terms of cell proliferation, colony-forming unit, cell cycle progression, cell migration, apoptosis and odonto/osteogenic differentiation of hDPSCs were assessed in the normal culture condition and P. gingivalis lipopolysaccharide (LPS)-induced 'inflammatory' milieus. RNA sequencing and proteomic analysis were performed to predict target pathways impacted by CBD.

RESULTS

CBD minimally affects hDPSCs' behaviour under normal culture growth milieu in normal conditions. However, an optimal concentration of 1.25 μg/mL CBD significantly countered the harmful effects of LPS, indicated by the promoting cell proliferation and restoring the odonto/osteogenic differentiation potential of hDPSCs under LPS-treated conditions. The proteomic analysis demonstrated that several proteins involved in cell proliferation and differentiation were upregulated following CBD exposure, including CCL8, CDC42 and KFL5. RNA sequencing data indicated that CBD upregulated the Notch signalling pathway. In an inhibitory experiment, DAPT, a Notch inhibitor, reduced the effect of CBD-rescued LPS-attenuated mineralization in hDPSCs, suggesting that CBD potentially mediates Notch activation to exert its impact on odonto/osteogenic differentiation of hDPSCs.

CONCLUSIONS

CBD recovers the proliferation and survival of hDPSCs following exposure to LPS. Additionally, we report that CBD-mediated Notch activation effectively restores the odonto/osteogenic differentiation ability of hDPSCs under inflamed conditions. These results underscore the potential role of CBD as a therapeutic option to enhance dentine regeneration.

Integrating Micro- and Nanostructured Platforms and Biological Drugs to Enhance Biomaterial-Based Bone Regeneration Strategies

Bone defects resulting from congenital anomalies and trauma pose significant clinical challenges for orthopedics surgeries, where bone tissue engineering (BTE) aims to address these challenges by repairing defects that fail to heal spontaneously. Despite numerous advances, BTE still faces several challenges, i.e., difficulties in detecting and tracking implanted cells, high costs, and regulatory approval hurdles. Biomaterials promise to revolutionize bone grafting procedures, heralding a new era of regenerative medicine and advancing patient outcomes worldwide. Specifically, novel bioactive biomaterials have been developed that promote cell adhesion, proliferation, and differentiation and have osteoconductive and osteoinductive characteristics, stimulating tissue regeneration and repair, particularly in complex skeletal defects caused by trauma, degeneration, and neoplasia. A wide array of biological therapeutics for bone regeneration have emerged, drawing from the diverse spectrum of gene therapy, immune cell interactions, and RNA molecules. This review will provide insights into the current state and potential of future strategies for bone regeneration.

Cannabidiol effects in stem cells: A systematic review

Stem cells play a critical role in human tissue regeneration and repair. In addition, cancer stem cells (CSCs), subpopulations of cancer cells sharing similar characteristics as normal stem cells, are responsible for tumor metastasis and resistance to chemo- and radiotherapy and to tumor relapse. Interestingly, all stem cells have cannabinoid receptors, such as cannabidiol (CBD), that perform biological functions. The aim of this systematic review was to analyze the effect of CBD on both somatic stem cells (SSCs) and CSCs. Of the 276 articles analyzed, 38 were selected according to the inclusion and exclusion criteria. A total of 27 studied the effect of CBD on SSCs, finding that 44% focused on CBD differentiation effect and 56% on its protective activity. On the other hand, 11 articles looked at the effect of CBD on CSCs, including glioblastoma (64%), lung cancer (27%), and breast cancer (only one article). Our results showed that CBD exerted a differentiating and protective effect on SCCs. In addition, this molecule demonstrated an antiproliferative effect on some CSCs, although most of the analyses were performed in vitro. Therefore, although in vivo studies should be necessary to justify its clinical use, CBD and its receptors could be a specific target to act on both SSCs and CSCs.

Exploring the Potential of Nonpsychoactive Cannabinoids in the Development of Materials for Biomedical and Sports Applications

This Perspective explores the potential of nonpsychoactive cannabinoids (NPCs) such as CBD, CBG, CBC, and CBN in developing innovative biomaterials for biomedical and sports applications. It examines their physicochemical properties, anti-inflammatory, analgesic, and neuroprotective effects, and their integration into various biomaterials such as hydrogels, sponges, films, and scaffolds. It also discusses the current challenges in standardizing formulations, understanding long-term effects, and understanding their intrinsical regulatory landscapes. Further, it discusses the promising applications of NPC-loaded materials in bone regeneration, wound management, and drug delivery systems, emphasizing their improved biocompatibility, mechanical properties, and therapeutic efficacy demonstrated in vitro and in vivo. The review also addresses innovative approaches to enhance NPC delivery including the use of computational tools and explores their potential in both biomedical and sports science contexts. By providing a comprehensive overview of the current state of research, this review aims to outline future directions, emphasizing the potential of NPCs in biomaterial science and regenerative medicine.

Effects of Cannabidiol on Bone Quality in Ovariectomized Rats

The incidence of osteoporosis and related fractures increases significantly with age, impacting public health and associated costs. Postmenopausal osteoporosis results from increased bone resorption due to decreased estrogen levels. The endocannabinoid system, especially cannabidiol (CBD), has shown therapeutic potential in modulating bone formation. This study investigated the effects of administration of CBD in rats after the onset of with ovariectomy-induced osteopenia (OVX). Forty-eight female Sprague‒Dawley rats were divided into four groups (n = 12): OVX + CBD, SHAM + CBD, OVX + vehicle, and SHAM + vehicle. CBD was administered intraperitoneally for 3 weeks. After euthanasia, the bone quality, mechanical properties, and bone microarchitecture of the femurs and lumbar vertebrae were assessed by microcomputed tomography (micro-CT), bone densitometry, mechanical tests, and histological and immunohistochemical analyses. CBD treatment improved the bone mineral density (BMD) of the lumbar vertebrae and increased the BV/TV% and Tb.N in the femoral neck. There were also improvements in the mechanical properties, such as the maximum force and stiffness of the femurs and vertebrae. CBD significantly increased the bone matrix in osteopenic femurs and vertebrae, Although did not significantly influence the expression of RANKL and OPG, in ovariectomized animals, there was an increase in osteoblasts and a decrease in osteoclasts. Determining the optimal timing for CBD use in relation to postovariectomy bone loss remains a crucial issue. Understanding when and how CBD can be most effective in preventing or treating bone loss is essential to emphasize the importance of early diagnosis and treatment of osteoporosis. However, further studies are needed to explore in more detail the efficacy and safety of CBD in the treatment of postmenopausal osteoporosis.

Revolutionizing bone defect healing: the power of mesenchymal stem cells as seeds

Bone defects can arise from trauma or pathological factors, resulting in compromised bone integrity and the loss or absence of bone tissue. As we are all aware, repairing bone defects is a core problem in bone tissue engineering. While minor bone defects can self-repair if the periosteum remains intact and normal osteogenesis occurs, significant defects or conditions such as congenital osteogenesis imperfecta present substantial challenges to self-healing. As research on mesenchymal stem cell (MSC) advances, new fields of application have emerged; however, their application in orthopedics remains one of the most established and clinically valuable directions. This review aims to provide a comprehensive overview of the research progress regarding MSCs in the treatment of diverse bone defects. MSCs, as multipotent stem cells, offer significant advantages due to their immunomodulatory properties and ability to undergo osteogenic differentiation. The review will encompass the characteristics of MSCs within the osteogenic microenvironment and summarize the research progress of MSCs in different types of bone defects, ranging from their fundamental characteristics and animal studies to clinical applications.

Unleashing the therapeutic role of cannabidiol in dentistry

Cannabidiol (CBD) found in Cannabis sativa is a non-psychoactive compound which is capable of binding to CB1 and CB2 receptors. CBD has recently gained interest in dentistry although it has not been explored sufficiently yet. The therapeutic effects of CBD include anti-inflammatory, analgesic, antioxidant, biological and osteoinductive properties. The aim of this review is to highlight these effects with respect to various oral conditions and shed light on the current limitations and prospects for the use of CBD in maintaining oral health.

Dental pulp stem cells-derived cannabidiol-treated organoid-like microspheroids show robust osteogenic potential via upregulation of WNT6

Dental pulp stem cells (DPSC) have shown osteogenic and bone regenerative potential. Improving the in situ bone regeneration potential of DPSC is crucial for their application as seed cells during bone defect reconstruction in clinics. This study aimed to develop DPSC-derived organoid-like microspheroids as effective seeds for bone tissue engineering applications. DPSC osteogenic microspheroids (70 μm diameter) were cultured in a polydimethylsiloxane-mold-based agarose-gel microwell-culture-system with or without cannabidiol (CBD)-treatment. Results of in vitro studies showed higher osteogenic differentiation potential of microspheroids compared with 2D-cultured-DPSC. CBD treatment further improved the osteogenic differentiation potential of microspheroids. The effect of CBD treatment in the osteogenic differentiation of microspheroids was more pronounced compared with that of CBD-treated 2D-cultured-DPSC. Microspheroids showed a higher degree of bone regeneration in nude mice calvarial bone defect compared to 2D-cultured-DPSC. CBD-treated microspheroids showed the most robust in situ bone regenerative potential compared with microspheroids or CBD-treated 2D-cultured-DPSC. According to mRNA sequencing, bioinformatic analysis, and confirmation study, the higher osteogenic potential of CBD-treated microspheroids was mainly attributed to WNT6 upregulation. Taken together, DPSC microspheroids have robust osteogenic potential and can effectively translate the effect of in vitro osteoinductive stimulation during in situ bone regeneration, indicating their application potential during bone defect reconstruction in clinics.

Cannabidiol prevents LPS-induced inflammation by inhibiting the NLRP3 inflammasome and iNOS activity in BV2 microglia cells via CB2 receptors and PPARγ

Neuroinflammation stands as a critical player in the pathogenesis of diverse neurological disorders, with microglial cells playing a central role in orchestrating the inflammatory landscape within the central nervous system. Cannabidiol (CBD) has gained attention for its potential to elicit anti-inflammatory responses in microglia, offering promising perspectives for conditions associated with neuroinflammation. Here we investigated whether the NLRP3 inflammasome and inducible nitric oxide synthase (iNOS) are involved in the protective effects of CBD, and if their modulation is dependent on cannabinoid receptor 2 (CB2) and PPARγ signalling pathways. We found that treatment with CBD attenuated pro-inflammatory markers in lipopolysaccharide (LPS)-challenged BV2 microglia in a CB2- and PPARγ-dependent manner. At a molecular level, CBD inhibited the LPS-induced pro-inflammatory responses by suppressing iNOS and NLRP3/Caspase-1-dependent signalling cascades, resulting in reduced nitric oxide (NO), interleukin-1β (IL-1β), and tumour necrosis factor-alpha (TNF-α) concentrations. Notably, the protective effects of CBD on NLRP3 expression, Caspase-1 activity, and IL-1β concentration were partially hindered by the antagonism of both CB2 receptors and PPARγ, while iNOS expression and NO secretion were dependent exclusively on PPARγ activation, with no CB2 involvement. Interestingly, CBD exhibited a protective effect against TNF-α increase, regardless of CB2 or PPARγ activation. Altogether, these findings indicate that CB2 receptors and PPARγ mediate the anti-inflammatory effects of CBD on the NLRP3 inflammasome complex, iNOS activity and, ultimately, on microglial phenotype. Our results highlight the specific components responsible for the potential therapeutic applications of CBD on neuroinflammatory conditions.

Cannabidiol and its application in the treatment of oral diseases: therapeutic potentials, routes of administration and prospects

Cannabidiol (CBD), one of the most important active ingredients in cannabis, has been reported to have some pharmacological effects such as antibacterial and analgesic effects, and to have therapeutic potential in the treatment of oral diseases such as oral cancer, gingivitis and periodontal diseases. However, there is a lack of relevant systematic research and reviews. Therefore, based on the etiology and clinical symptoms of several common oral diseases, this paper focuses on the therapeutic potential of CBD in periodontal diseases, pulp diseases, oral mucosal diseases, oral cancer and temporomandibular joint diseases. The pharmacological effects of CBD and the distribution and function of its receptors in the oral cavity are also summarized. In order to provide reference for future research and further clinical application of CBD, we also summarize several possible routes of administration and corresponding characteristics. Finally, the challenges faced while applying CBD clinically and possible solutions are discussed, and we also look to the future.

How Biodegradable Polymers Can be Effective Drug Delivery Systems for Cannabinoids? Prospectives and Challenges

Cannabinoids are compounds found in and derived from the Cannabis plants that have become increasingly recognised as significant modulating factors of physiological mechanisms and inflammatory reactions of the organism, thus inevitably affecting maintenance of homeostasis. Medical Cannabis popularity has surged since its legal regulation growing around the world. Numerous promising discoveries bring more data on cannabinoids' pharmacological characteristics and therapeutic applications. Given the current surge in interest in the medical use of cannabinoids, there is an urgent need for an effective method of their administration. Surpassing low bioavailability, low water solubility, and instability became an important milestone in the advancement of cannabinoids in pharmaceutical applications. The numerous uses of cannabinoids in clinical practice remain restricted by limited administration alternatives, but there is hope when biodegradable polymers are taken into account. The primary objective of this review is to highlight the wide range of indications for which cannabinoids may be used, as well as the polymeric carriers that enhance their effectiveness. The current review described a wide range of therapeutic applications of cannabinoids, including pain management, neurological and sleep disorders, anxiety, and cancer treatment. The use of these compounds was further examined in the area of dermatology and cosmetology. Finally, with the use of biodegradable polymer-based drug delivery systems (DDSs), it was demonstrated that cannabinoids can be delivered specifically to the intended site while also improving the drug's physicochemical properties, emphasizing their utility. Nevertheless, additional clinical trials on novel cannabinoids' formulations are required, as their full spectrum therapeutical potential is yet to be unravelled.

Effect of recreational cannabis use on bone mineral density: a systematic review

The recreational use of cannabis products has risen considerably worldwide over the past decade. As the cannabis legal market grows, a critical challenge has been to make substantiated claims about the benefits and adverse health problems triggered by cannabis exposure. Despite accumulating evidence from animal studies demonstrating the role of cannabinoids on bone metabolism, there are conflicting results in clinical literature regarding their effects on bone health outcomes.We undertook a systematic review to assess the evidence for the safety of cannabis use on bone health. We searched the databases MEDLINE, EMBASE, Cochrane Library, and Web of Science up to March 2023 for studies evaluating the effect of the recreational use of cannabis on the bone mineral density (BMD) of adults.Among the 2620 studies reviewed, three cross-sectional studies and one randomized controlled trial comprised 4032 participants from 18 to 60 years who met the inclusion criteria. Two studies showed that cannabis exposure decreased BMD, while the other 2 indicated no alteration. Despite the different study designs, the included studies showed a low risk of bias according to the Joanna Briggs Institute tool.Eligible studies present differences in cannabis products, administration routes, and exposure determination. Further longitudinal research is needed to establish multiple clinical predictors associated with potentially negative consequences of cannabis exposure, especially in vulnerable populations such as elderly individuals.

Cannabidiol-loaded microparticles embedded in a porous hydrogel matrix for biomedical applications

In this study, poly (lactic-co-glycolic acid) (PLGA) microparticles loaded with cannabidiol (CBD) were synthesized (PLGA@CBD microparticles) and embedded up to 10 wt% in a chondroitin sulfate/polyvinyl alcohol hydrogel matrix. In vitro chemical, physical, and biological assays were carried out to validate the potential use of the modified hydrogels as biomaterials. The microparticles had spherical morphology and a narrow range of size distribution. CBD encapsulation efficiency was around 52%, loading was approximately 50%. Microparticle addition to the hydrogels caused minor changes in their morphology, FTIR and thermal analyses confirmed these changes. Swelling degree and total porosity were reduced in the presence of microparticles, but similar hydrophilic and degradation in phosphate buffer solution behaviors were observed by all hydrogels. Rupture force and maximum strain at rupture were higher in the modified hydrogels, whereas modulus of elasticity was similar across all materials. Viability of primary human dental pulp cells up to 21 days was generally not influenced by the addition of PLGA@CBD microparticles. The control hydrogel showed no antimicrobial activity against Staphylococcus aureus, whereas hydrogels with 5% and 10% PLGA@CBD microparticles showed inhibition zones. In conclusion, the PLGA@CBD microparticles were fabricated and successfully embedded in a hydrogel matrix. Despite the hydrophobic nature of CBD, the physicochemical and morphological properties were generally similar for the hydrogels with and without the CBD-loaded microparticles. The data reported in this study suggested that this original biomaterial loaded with CBD oil has characteristics that could enable it to be used as a scaffold for tissue/cellular regeneration.

Serum Markers of Bone Turnover Following Controlled Administration of Two Medical Cannabis Products in Healthy Adults

Introduction: Cannabidiol (CBD) has been shown to maintain bone integrity in pre-clinical models, but little is known about the effects of delta-9-tetrahydrocannabinol (THC) on bone turnover. In this study we explored the effects of two oral medical cannabis products on normal bone homeostasis through evaluation of markers of bone resorption (carboxyl-terminal collagen crosslinks, CTx) and bone formation (procollagen type 1 N-terminal propeptide, P1NP; alkaline phosphatase, ALP). Methods: This study is an analysis of secondary data from two Phase 1 double-blind, placebo-controlled trials of Spectrum Yellow (0.9 mg THC, 20 mg CBD/mL of oil) and Spectrum Red (2.5 mg THC, 0.3 mg CBD/softgel). Healthy participants (n=38 men, 45 women) were randomized to receive 5-20 mg THC (CBD levels varied as a function of administered product) or placebo daily (BID) for 7 days. Bone markers were assessed at baseline, upon completion of product administration (day 8), and after a 5-day washout (day 13). Results: All bone markers were significantly higher in men at baseline (p≤0.008). For CTx, there was a significant day×group interaction (F=3.23, p=0.04); CTx levels were significantly lower in participants treated with Spectrum Red (b=-164.28; 95% confidence interval [CI], -328 to -0.29; p=0.04) and marginally lower in participants treated with Spectrum Yellow (b=-157.31; 95% CI, -323 to 8.68; p=0.06) versus placebo on day 8. For P1NP and ALP, there were no significant differences between treatments across study days. Bone marker values outside the reference range (RR) were observed; CTx > RR (n=71) was predominantly (85.9%) observed in male participants, whereas P1NP > RR (n=100) was more evenly distributed between sexes (53.0% in men). These were not considered clinically significant and did not differ between treatment groups. Conclusions: These are the first interventional human data on the effect of cannabinoids on biomarkers of bone turnover. Short-term treatment with CBD- or THC-dominant medical cannabis products resulted in attenuation of a marker of bone resorption. Although the attenuation was not clinically significant, this finding may be indicative of protective properties of cannabinoids in bone. Further research over longer dosing durations in individuals exhibiting bone-specific conditions (e.g., osteoporosis) is warranted. ClinicalTrials.gov IDs: ACTRN12619001723178 and ACTRN12619001450101.

Nanocarriers for Cannabinoid Delivery: Enhancing Therapeutic Potential

Medical cannabis has potential therapeutic benefits in managing pain, anxiety, depression, and neurological and movement disorders. Phytocannabinoids derived from the cannabis plant are responsible for their pharmacological and therapeutic properties. However, the complexity of cannabis components, especially cannabinoids, poses a challenge to effective medicinal administration. Even with the increasing acceptance of cannabis-based medicines, achieving consistent bioavailability and targeted distribution remains difficult. Conventional administration methods are plagued by solubility and absorption problems requiring innovative solutions. After conducting a thorough review of research papers and patents, it has become evident that nanotechnology holds great promise as a solution. The comprehensive review of 36 research papers has yielded valuable insights, with 7 papers reporting enhanced bioavailability, while others have focused on improvements in release, solubility, and stability. Additionally, 19 patents have been analyzed, of which 7 specifically claim enhanced bioavailability, while the remaining patents describe various formulation methods. These patents outline effective techniques for encapsulating cannabis using nanocarriers, effectively addressing solubility and controlled release. Studies on the delivery of cannabis using nanocarriers focus on improving bioavailability, prolonging release, and targeting specific areas. This synthesis highlights the potential of nanotechnology to enhance cannabis therapies and pave the way for innovative interventions and precision medicine.

Cell electrospinning and its application in wound healing: principles, techniques and prospects

Currently, clinical strategies for the treatment of wounds are limited, especially in terms of achieving rapid wound healing. In recent years, based on the technique of electrospinning (ES), cell electrospinning (C-ES) has been developed to better repair related tissues or organs (such as skin, fat and muscle) by encapsulating living cells in a microfiber or nanofiber environment and constructing 3D living fiber scaffolds. Therefore, C-ES has promising prospects for promoting wound healing. In this article, C-ES technology and its advantages, the differences between C-ES and traditional ES, the parameters suitable for maintaining cytoactivity, and material selection and design issues are summarized. In addition, we review the application of C-ES in the fields of biomaterials and cells. Finally, the limitations and improved methods of C-ES are discussed. In conclusion, the potential advantages, limitations and prospects of C-ES application in wound healing are presented.

Oral Cannabidiol Treatment in Two Postmenopausal Women with Osteopenia: A Case Series

Introduction: Cannabidiol (CBD), a nonintoxicating cannabinoid, may be involved in bone remodeling, but human studies are limited. In this case series, we explored the effects of oral CBD administration on bone turnover. Materials and Methods: Two postmenopausal women with osteopenia (T-score=-1 to -2.5) were randomized to receive 100 or 300 mg CBD daily (oral, bis in die [twice per day]) for 12 weeks. Serum markers of bone resorption (carboxyl-terminal collagen crosslinks [CTx]) and bone formation (procollagen type 1 N-terminal propeptide [P1NP], bone-specific alkaline phosphatase [BSAP], and osteocalcin [OC]); safety measures; plasma concentrations of CBD and metabolites; sleep disturbance; symptoms of depression, anxiety, and stress; and quality of life, were assessed. Results: CBD was well tolerated, with no clinically significant change in vital signs, hematology, chemistry, or urinalysis, and no adverse events reported. Reductions (% change vs. baseline) in CTx (-8.5%, -28.1%), P1NP (-9.9%, -39.5%), BSAP (-12.7%, -74.8%), and OC (-16.0%, -6.7%) were observed after 12 weeks of oral administration of 100 or 300 mg CBD daily, respectively. The two participants self-reported consuming 95.3% and 98.8% of CBD doses, respectively. CBD and select metabolites were measurable in plasma after 4 and 12 weeks of CBD treatment. No notable changes in sleep disturbance, depression, anxiety, stress, or quality of life were observed. Conclusions: CBD was well tolerated after 12 weeks of twice-daily oral administration and was associated with reduction in measured markers of bone turnover. Compliance with CBD treatment was good. Large-scale randomized clinical trials into the bone protective effects of CBD in postmenopausal women are warranted.

Research Progress of Design Drugs and Composite Biomaterials in Bone Tissue Engineering

Bone, like most organs, has the ability to heal naturally and can be repaired slowly when it is slightly injured. However, in the case of bone defects caused by diseases or large shocks, surgical intervention and treatment of bone substitutes are needed, and drugs are actively matched to promote osteogenesis or prevent infection. Oral administration or injection for systemic therapy is a common way of administration in clinic, although it is not suitable for the long treatment cycle of bone tissue, and the drugs cannot exert the greatest effect or even produce toxic and side effects. In order to solve this problem, the structure or carrier simulating natural bone tissue is constructed to control the loading or release of the preparation with osteogenic potential, thus accelerating the repair of bone defect. Bioactive materials provide potential advantages for bone tissue regeneration, such as physical support, cell coverage and growth factors. In this review, we discuss the application of bone scaffolds with different structural characteristics made of polymers, ceramics and other composite materials in bone regeneration engineering and drug release, and look forward to its prospect.

Cannabidiol for Oral Health: A New Promising Therapeutical Tool in Dentistry

The medical use of cannabis has a very long history. Although many substances called cannabinoids are present in cannabis, Δ9tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD) and cannabinol (CBN) are the three main cannabinoids that are most present and described. CBD itself is not responsible for the psychotropic effects of cannabis, since it does not produce the typical behavioral effects associated with the consumption of this drug. CBD has recently gained growing attention in modern society and seems to be increasingly explored in dentistry. Several subjective findings suggest some therapeutic effects of CBD that are strongly supported by research evidence. However, there is a plethora of data regarding CBD's mechanism of action and therapeutic potential, which are in many cases contradictory. We will first provide an overview of the scientific evidence on the molecular mechanism of CBD's action. Furthermore, we will map the recent developments regarding the possible oral benefits of CBD. In summary, we will highlight CBD's promising biological features for its application in dentistry, despite exiting patents that suggest the current compositions for oral care as the main interest of the industry.

Cannabidiol-Loaded Nanocarriers and Their Therapeutic Applications

Cannabidiol (CBD), one of the most promising constituents isolated from Cannabis sativa, exhibits diverse pharmacological actions. However, the applications of CBD are restricted mainly due to its poor oral bioavailability. Therefore, researchers are focusing on the development of novel strategies for the effective delivery of CBD with improved oral bioavailability. In this context, researchers have designed nanocarriers to overcome limitations associated with CBD. The CBD-loaded nanocarriers assist in improving the therapeutic efficacy, targetability, and controlled biodistribution of CBD with negligible toxicity for treating various disease conditions. In this review, we have summarized and discussed various molecular targets, targeting mechanisms and types of nanocarrier-based delivery systems associated with CBD for the effective management of various disease conditions. This strategic information will help researchers in the establishment of novel nanotechnology interventions for targeting CBD.

In situ Formation of Polymer Microparticles in Bacterial Nanocellulose Using Alternative and Sustainable Solvents to Incorporate Lipophilic Drugs

Bacterial nanocellulose has been widely investigated in drug delivery, but the incorporation of lipophilic drugs and controlling release kinetics still remain a challenge. The inclusion of polymer particles to encapsulate drugs could address both problems but is reported sparely. In the present study, a formulation approach based on in situ precipitation of poly(lactic-co-glycolic acid) within bacterial nanocellulose was developed using and comparing the conventional solvent N-methyl-2-pyrrolidone and the alternative solvents poly(ethylene glycol), Cyrene^TM and ethyl lactate. Using the best-performing solvents N-methyl-2-pyrrolidone and ethyl lactate, their fast diffusion during phase inversion led to the formation of homogenously distributed polymer microparticles with average diameters between 2.0 and 6.6 µm within the cellulose matrix. Despite polymer inclusion, the water absorption value of the material still remained at ~50% of the original value and the material was able to release 32 g/100 cm² of the bound water. Mechanical characteristics were not impaired compared to the native material. The process was suitable for encapsulating the highly lipophilic drugs cannabidiol and 3-O-acetyl-11-keto-β-boswellic acid and enabled their sustained release with zero order kinetics over up to 10 days. Conclusively, controlled drug release for highly lipophilic compounds within bacterial nanocellulose could be achieved using sustainable solvents for preparation.

Advent of phytobiologics and nano-interventions for bone remodeling: a comprehensive review

Bone metabolism constitutes the intricate processes of matrix deposition, mineralization, and resorption. Any imbalance in these processes leads to traumatic bone injuries and serious disease conditions. Therefore, bone remodeling plays a crucial role during the regeneration process maintaining the balance between osteoblastogenesis and osteoclastogenesis. Currently, numerous phytobiologics are emerging as the new therapeutics for the treatment of bone-related complications overcoming the synthetic drug-based side effects. They can either target osteoblasts, osteoclasts, or both through different mechanistic pathways for maintaining the bone remodeling process. Although phytobiologics have been widely used since tradition for the treatment of bone fractures recently, the research is accentuated toward the development of osteogenic phytobioactives, constituent-based drug designing models, and efficacious delivery of the phytobioactives. To achieve this, different plant extracts and successful isolation of their phytoconstituents are critical for osteogenic research. Hence, this review emphasizes the phytobioactives based research specifically enlisting the plants and their constituents used so far as bone therapeutics, their respective isolation procedures, and nanotechnological interventions in bone research. Also, the review enlists the vast array of folklore plants and the newly emerging nano-delivery systems in treating bone injuries as the future scope of research in the phytomedicinal orthopedic applications.

Evaluation of the efficacy of a cannabidiol and cannabidiolic acid rich hemp extract for pain in dogs following a tibial plateau leveling osteotomy

Objective

To determine the impact of a cannabidiol (CBD) and cannabidiolic acid (CBDA) rich hemp product on acute post-operative pain in dogs following a tibial plateau leveling osteotomy (TPLO), and to evaluate for changes in early bone healing, serum chemistry profiles, and complete blood counts.

Methods

In this randomized, placebo controlled, blinded clinical trial, 44 client-owned dogs were assigned to receive either a CBD/CBDA product dosed at 2-2.5 mg/kg PO every 12 h or a placebo for 4 weeks following a TPLO. Variables evaluated before (week 0), and at 2 and 4 weeks post-operatively included standardized veterinary assessments for pain score, weight-bearing, and lameness, the Canine Brief Pain Inventory (pain interference score-PIS, pain severity score-PSS), and serum biochemistry. Complete blood counts were performed at weeks 0 and 4. Additionally, orthogonal radiographs evaluating the degree of healing were taken at week 4. A mixed model analysis, analyzing changes of variables of interest from enrollment baseline to all other time points was utilized, with a p-value ≤ 0.05 considered significant.

Results

Of the 44 enrolled patients, 3 were lost to follow up and excluded from analysis. No significant differences were noted between placebo (n = 19) and CBD/CBDA (n = 22) groups at any point in pain score, degree of lameness, degree of weight-bearing, PIS, PSS, or radiographic healing of the osteotomy. A significant finding of elevation of ALP above normal reference range in the treatment group was identified (p = 0.02) and eosinophil count was affected by treatment (p = 0.01), increasing from baseline in placebo and decreasing in treatment groups. Finally, a significant difference (p = 0.03) was noted at 2 weeks post-operatively where 4 patients in the placebo group and no treatment patients received trazodone to facilitate activity restrictions.

Clinical significance

Use of a CBD/CBDA rich hemp product dosed at 2-2.5 mg/kg PO every 12 h did not have a significant impact on pain or delay early bone healing. A statistically significant increase in ALP, decrease in eosinophils, and reduced use of trazodone was identified in the treatment group.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

Cannabidiol in Dentistry: A Scoping Review

Cannabidiol (CBD) has been gaining increased attention in contemporary society but seems to have been little explored in dentistry. This scoping review mapped the scientific and technological scenarios related to the use of CBD in dentistry. Peer-reviewed publications were searched in five international databases, patents were searched in five technological platforms. In total, 11 articles and 13 patents involving CBD in dentistry-related applications were included. The countries contributing to most articles were Brazil (27.3%) and USA (18.2%). The studies involved experiments on animals (63.6%) and/or using bacteria or cells (36.4%), and no clinical study was found. Three different applications of CBD were observed: periodontal therapy (45.4%), aid for bone regeneration (27.3%), and general use in oral therapies (27.3%). Patent inventors were based in China (53.8%) or USA (46.2%). The patent claims were mainly compositions for oral care, tooth whitening, injury repair, antifungal, anti-inflammatory, and analgesic effects. A total of 76.9% of the patents were filed in association with a company. In general, research suggests that CBD has promising biological properties for applications in dentistry, whereas patents indicate that the current interest of industry relies on compositions for oral care. There appears to be extensive room available for research and technological applications of CBD in dentistry.

Research on the osteogenesis and biosafety of ECM–Loaded 3D–Printed Gel/SA/58sBG scaffolds

Employing scaffolds containing cell–derived extracellular matrix (ECM) as an alternative strategy for the regeneration of bone defects has shown prominent advantages. Here, gelatin (Gel), sodium alginate (SA) and 58s bioactive glass (58sBG) were incorporated into deionized water to form ink, which was further fabricated into composite scaffolds by the 3D printing technique. Then, rat aortic endothelial cells (RAOECs) or rat bone mesenchymal stem cells (RBMSCs) were seeded on the scaffolds. After decellularization, two kinds of ECM–loaded scaffolds (RAOECs–ECM scaffold and RBMSCs–ECM scaffold) were obtained. The morphological characteristics of the scaffolds were assessed meticulously by scanning electron microscopy (SEM). In addition, the effects of scaffolds on the proliferation, adhesion, and osteogenic and angiogenic differentiation of RBMSCs were evaluated by Calcein AM staining and reverse transcription polymerase chain reaction (RT–PCR). In vivo, full–thickness bone defects with a diameter of 5 mm were made in the mandibles of Sprague–Dawley (SD) rats to assess the bone regeneration ability and biosafety of the scaffolds at 4, 8 and 16 weeks. The osteogenic and angiogenic potential of the scaffolds were investigated by microcomputed tomography (Micro–CT) and histological analysis. The biosafety of the scaffolds was evaluated by blood biochemical indices and histological staining of the liver, kidney and cerebrum. The results showed that the ECM–loaded scaffolds were successfully prepared, exhibiting interconnected pores and a gel–like ECM distributed on their surfaces. Consistently, in vitro experiments demonstrated that the scaffolds displayed favourable cytocompatibility. In vitro osteogenic differentiation studies showed that scaffolds coated with ECM could significantly increase the expression of osteogenic and angiogenic genes. In addition, the results from mandibular defect repair in vivo revealed that the ECM–loaded scaffolds effectively promoted the healing of bone defects when compared to the pure scaffold. Overall, these findings demonstrate that both RAOECs–ECM scaffold and RBMSCs–ECM scaffold can greatly enhance bone formation with good biocompatibility and thus have potential for clinical application in bone regeneration.

Peptide-Grafted Microspheres for Mesenchymal Stem Cell Sorting and Expansion by Selective Adhesion

Mesenchymal stem cells (MSCs) have considerable value in regenerative medicine because of their unique properties such as pluripotency, self-renewal ability, and low immunogenicity. Isolation and purification are prerequisites for various biomedical applications of MSCs, and traditional sorting methods are often expensive, complicated, and difficult to apply on a large scale. In addition to purification, the requirement for expansion of cells also limits the further application of MSCs. The purpose of this study was to develop a unique magnetic sorting microsphere to obtain relatively pure and high-yield MSCs in an economical and effective way, that can also be used for the expansion of MSCs. Poly (ethylene glycol) (PEG)-based anti-adhesive treatment of the prepared oleic acid grafted Fe3O4-poly (lactic-co-glycolic acid) magnetic microspheres was performed, and then E7 peptide was covalently grafted onto the treated microspheres. Upon a series of characterization, the magnetic microspheres were of uniform size, and cells were unable to adhere to the PEG-treated surface. E7 grafting significantly improved cell adhesion and proliferation. The results obtained from separate culture of various cell types as well as static or dynamic co-culture showed that selective adhesion of MSCs was observed on the magnetic sorting microspheres. Furthermore, the cells expanded on the microspheres maintained their phenotype and typical differentiation potentials. The magnetic properties of the microspheres enabled sampling, distribution, and transfer of cells without the usage of trypsin digestion. And it facilitated the separation of cells and microspheres for harvesting of MSCs after digestion. These findings have promising prospects for MSC research and clinical applications.

Marijuana in Orthopaedics: Effects on Bone Health, Wound-Healing, Surgical Complications, and Pain Management

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Marijuana use is on the rise in the United States, and there is a paucity of information on the effects of cannabis and its chemical constituents on bone health, wound-healing, surgical complications, and pain management.

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Current evidence suggests that cannabidiol (CBD) may enhance bone health and metabolism, while Δ9-tetrahydrocannabinol (Δ9-THC), the major psychoactive component in marijuana, has an inhibitory effect.

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Marijuana users are at higher risk for delayed bone-healing, demonstrate lower bone mineral density, are at increased risk for fracture, and may experience postoperative complications such as increased opioid use and hyperemesis.

Effects of Marijuana Use in Patients with Orthopaedic Trauma

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The use of cannabis and cannabis-related products has increased dramatically in the last 2 decades. As states continue to legalize cannabis products, it is important for surgeons to understand the effects they may have on patients who have sustained orthopaedic trauma.

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Cannabinoids have been shown to decrease the severity of certain symptoms related to traumatic brain injury as well as posttraumatic stress disorder.

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Cannabinoids can modulate the body's endocannabinoid system, which can play an important role in bone homeostasis. Activation of cannabinoid receptors has been shown to be bone-protective in adults.

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Venous thromboembolism is a major concern for trauma patients. Cannabis use has been linked to overall increased rates of venous thromboembolism events.

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Literature regarding human-based cannabis studies is sparse; however, the growing field is opening new opportunities for research of this topic.

Investigation of in vitro odonto/osteogenic capacity of cannabidiol on human dental pulp cell

INTRODUCTION

Vital pulp treatment (VPT) maintains tooth vitality with certain dental materials by protecting pulp from noxious stimulation and promoting repair through enhancing cell proliferation/differentiation, migration, and inducing odontogenesis. As a non-psychotropic cannabis constituent, cannabidiol (CBD) possesses the properties of analgesic, anti-inflammation, and osteogenesis. Therefore, we hypothesize that CBD may induce the odonto/osteogenesis of human dental pulp cells (HDPCs), a critical feature using as effective pulp capping agent for VPT.

MATERIALS AND METHODS

In this in vitro study, the cytotoxicity of CBD on HDPCs was determined by MTT assay. Scratch assay was performed to analyze HDPC migration. The biomineralization was examined by collagen synthesis and calcium nodule formation and related odonto/osteogenic and angiogenic genes. Cannabinoid receptor (CB) specificity was evaluated by Western blotting and Von Kossa staining using specific antagonists AM251 for cannabinoid receptor 1 (CB1) and AM 630 targeted at cannabinoid receptor 2 (CB2). In addition, the underlying molecular mechanism of CBD-induced biomineralization were investigated by examining CB-dependent MAPK signaling pathways.

RESULTS

CBD demonstrated bi-phasic effects on HDPC viability in tested concentrations. We found CBD significantly promoted cell migration, enhanced collagen synthesis and mineralized deposits in HDPCs when treated by 1 μM CBD supplemented in the differentiation media. RT-PCR revealed CBD increased the expression of angiogenic and odontogenic genes, such as DSPP, DMP-1, OPN, ALP, Runx2, VEGFR1 and ICAM-1. These effects were via MAPK activation in a manner mainly mediated by CB2.

CONCLUSION

The results from this study suggested that CBD can induce odonto/osteogenesis from HDPCs and has the potential to develop new therapeutics in VPT in dentistry.

The Effects of Cannabis: Implications for the Surgical Patient

Background:

Cannabis use is increasingly prevalent. Cannabinoid receptors regulate pro-inflammatory cytokines, and compounds in marijuana exert diverse physiologic effects. As more patients use cannabis, clinicians should recognize implications of perioperative cannabis use. Although the role of cannabis use in perioperative pain control has been explored, little is known about its effect on perioperative wound healing or on hematologic, pulmonary, and cardiovascular physiology.

Methods:

We searched PubMed for English-language articles related to cannabis (ie, marijuana, cannabidiol oil, and tetrahydrocannabinol) and wound healing, cardiovascular, pulmonary, or hematologic outcomes, and surgery. Titles and abstracts were reviewed, and relevant articles were analyzed. Human, animal, and pathology studies were included. Editorials, case reports, and review articles were excluded.

Results:

In total, 2549 wound healing articles were identified; 5 human studies and 8 animal/pathology studies were included. Results were conflicting. An estimated 2900 articles related to cardiovascular effects were identified, of which 2 human studies were included, which showed tetrahydrocannabinol and marijuana caused tachycardia. A total of 142 studies regarding pulmonary effects were identified. Three human studies were included, which found no difference in respiratory complications. In total, 114 studies regarding hematologic effects were identified. The 3 included human studies found conflicting venous thromboembolism risks. The overall study quality was poor. Information about dose/duration, administration route, and follow-up was reported with variable completeness.

Conclusions:

Surgeons should consider effects of cannabis in the perioperative setting. Little is known about its perioperative effects on wound healing, or on cardiovascular, pulmonary, and hematologic physiology. Further research should elucidate the effects of administration route, dose, and timing of cannabis use among surgical patients.

Stem cell recruitment based on scaffold features for bone tissue engineering

Stem-cell based therapy strategies are promising approaches for the treatment of bone defects. However, extensive cell expansion steps, the low rate of cell survival and uncontrolled differentiation of stem cells transplanted into the body currently remain key challenges in advancing stem cell therapeutics. An alternative strategy is to use specifically designed bone scaffolds to recruit endogenous stem cells upon implantation and to stimulate new bone formation and remodeling. Stem cell recruitment based on scaffold features for bone tissue engineering relies on the development of scaffolds that can effectively mobilize and recruit endogenous stem cells to the implantation site. This article addresses the recent advances in the recruitment of endogenous stem cells in applications of bone scaffolds, particularly focusing on chemical modification and physical characteristic modification of the scaffold for endogenous stem cell homing and recruitment. Finally, the continuing challenges and future directions of scaffold-based stem cell recruitment are discussed.

Cannabidiol and Vitamin D3 Impact on Osteogenic Differentiation of Human Dental Mesenchymal Stem Cells

Background and objective: The aim of the present study was to establish a new differentiation protocol using cannabidiol (CBD) and vitamin D3 (Vit. D3) for a better and faster osteogenic differentiation of dental tissue derived mesenchymal stem cells (MSCs). Materials and methods: MSCs were harvested from dental follicle (DFSCs), dental pulp (DPSCs), and apical papilla (APSCs) of an impacted third molar of a 17-year old patient. The stem cells were isolated and characterized using flow cytometry; reverse transcription polymerase chain reaction (RT-PCR); and osteogenic, chondrogenic, and adipogenic differentiation. The effects of CBD and Vit. D3 on osteogenic differentiation of dental-derived stem cell were evaluated in terms of viability/metabolic activity by alamar test, expression of collagen1A, osteopontin (OP), osteocalcin (OC), and osteonectin genes and by quantification of calcium deposits by alizarin red assay. Results: Stem cell characterization revealed more typical stemness characteristics for DFSCs and DPSCs and atypical morphology and markers expression for APSCs, a phenotype that was confirmed by differences in multipotential ability. The RT-PCR quantification of bone matrix proteins expression revealed a different behavior for each cell type, APSCs having the best response for CBD. DPSCs showed the best osteogenic potential when treated with Vit. D3. Cultivation of DFSC in standard stem cell conditions induced the highest expression of osteogenic genes, suggesting the spontaneous differentiation capacity of these cells. Regarding mineralization, alizarin red assay indicated that DFSCs and APSCs were the most responsive to low doses of CBD and Vit. D3. DPSCs had the lowest mineralization levels, with a slightly better response to Vit. D3. Conclusions: This study provides evidence that DFSCs, DPSCs, and APSCs respond differently to osteoinduction stimuli and that CBD and Vit. D3 can enhance osteogenic differentiation of these types of cells under certain conditions and doses.

The Cannabinoids Effect on Bone Formation and Bone Healing

PURPOSE OF REVIEW

Here, we overview the latest findings from studies investigating the skeletal endocannabinoid (EC) system and its involvement in bone formation and resorption.

RECENT FINDINGS

The endocannabinoid system consists of endogenous ligands, receptors, and enzymes. The main cannabinoids found in the cannabis plant are Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabinoid receptors CB1 and CB2 are expressed in bone and regulate bone homeostasis in rodents and humans. CBD treatment was shown to enhance fracture healing in rats. Recent studies in mice indicate that strain, age, and sex differences dictate the skeletal outcome of the EC activation. CBD treatment was shown to enhance bone healing, but needs validation in clinical trials. While research shows that EC activity protects against bone loss, studies on CB1 and CB2 agonists in bone regeneration models are lacking. Whether modulating the EC system would affect bone repair remains therefore an open question worth investigating.

Cannabinoid Use in Musculoskeletal Illness: a Review of the Current Evidence

PURPOSE OF REVIEW

The use of cannabinoids has increased since legalization of recreational and medical use in the USA. It is likely that many orthopaedic patients consume cannabinoid products during the traumatic or perioperative period. The purpose of this study was to investigate the pre-clinical data evaluating the mechanism of action of cannabidiol (CBD) and Δ9-Tetrahydrocannabinol (Δ9-THC) and to evaluate the current clinical data on the use of cannabinoids in musculoskeletal illness.

RECENT FINDINGS

Recent pre-clinical studies have demonstrated that cannabinoid use and the endocannabinoid system (ECS) has an important role in bone healing and bone homeostasis. There is data that suggests that the use of cannabidiol (CBD) may increase bone healing, whereas the use of Δ9-Tetrahydrocannabinol (Δ9-THC), the major psychoactive ingredient in marijuana, likely inhibits bone metabolism and repair. The clinical implications and consumption of marijuana by orthopaedic patients have not been thoroughly evaluated. Studies have demonstrated concern for negative cardiovascular and psychiatric effects caused by marijuana use, but have not yet elucidated outcomes in the orthopaedic literature. With the recent increase in advertising of CBD products and legalization of marijuana, it is likely that many orthopaedic patients are consuming cannabinoid products. The clinical implications and consumption of these products are unclear. We need more robust and well-designed clinical studies prior to making further recommendations to our patients on the consumption of these products.

Biodegradable Polymers as the Pivotal Player in the Design of Tissue Engineering Scaffolds

Biodegradable polymers play a pivotal role in in situ tissue engineering. Utilizing various technologies, researchers have been able to fabricate 3D tissue engineering scaffolds using biodegradable polymers. They serve as temporary templates, providing physical and biochemical signals to the cells and determining the successful outcome of tissue remodeling. Furthermore, a biodegradable scaffold also presents the fourth dimension for tissue engineering, namely time. The properties of the biodegradable polymer change over time, presenting continuously changing features during the degradation process. These changes become more complicated when different materials are combined together to fabricate a composite or heterogeneous scaffold. This review undertakes a systematic analysis of the basic characteristics of biodegradable polymers and describe recent advances in making composite biodegradable scaffolds for in situ tissue engineering and regenerative medicine. The interaction between implanted biodegradable biomaterials and the in vivo environment are also discussed, including the properties and functional changes of the degradable scaffold, the local effect of degradation on the contiguous tissue and their evaluation using both in vitro and in vivo models.

Recruitment of Mesenchymal Stem Cells to Damaged Sites by Plant-Derived Components

Mesenchymal stem cells (MSCs) are capable of differentiating into a limited number of diverse cells and secrete regenerative factors that contribute to the repair of damaged tissue. In response to signals emitted by tissue damage, MSCs migrate from the bone marrow and area surrounding blood vessels within tissues into the circulating blood, and accumulate at the site of damage. Hence, MSC transplantation therapy is beginning to be applied to the treatment of various intractable human diseases. Recent medicinal plants studies have shown that plant-derived components can activate cell functions. For example, several plant-derived components activate cell signaling pathways, such as phosphatidylinositol 3-kinase and mitogen-activated protein kinase (MAPK), enhance expression of the CXCL12/CXCR4 axis, stimulate extracellular matrix remodeling, and consequently, promote cell migration of MSCs. Moreover, plant-derived components have been shown to promote recruitment of MSCs to damaged tissues and enhance healing in disease models, potentially advancing their therapeutic use. This article provides a comprehensive review of several plant-derived components that activate MSC migration and homing to damaged sites to promote tissue repair.

Full-Spectrum Cannabis Extract Microdepots Support Controlled Release of Multiple Phytocannabinoids for Extended Therapeutic Effect

The therapeutic effect of the Cannabis plant largely depends on the presence and specific ratio of a spectrum of phytocannabinoids. Although prescription of medicinal Cannabis for various conditions constantly grows, its consumption is mostly limited to oral or respiratory pathways, impeding its duration of action, bioavailability, and efficacy. Herein, a long-acting formulation in the form of melt-printed polymeric microdepots for full-spectrum cannabidiol (CBD)-rich extract administration is described. When injected subcutaneously in mice, the microdepots facilitate sustained release of the encapsulated extract over a two-week period. The prolonged delivery results in elevated serum levels of multiple, major and minor, phytocannabinoids for over 14 days, compared to Cannabis extract injection. A direct analysis of the microdepots retrieved from the injection site gives rise to an empirical model for the release kinetics of the phytocannabinoids as a function of their physical traits. As a proof of concept, we compare the long-term efficacy of a single administration of the microdepots to a single administration of Cannabis extract in a pentylenetetrazol-induced convulsion model. One week following administration, the microdepots reduce the incidence of tonic-clonic seizures by 40%, increase the survival rate by 50%, and the latency to first tonic-clonic seizures by 170%. These results suggest that a long-term full-spectrum Cannabis delivery system may provide new form of Cannabis administration and treatments.

Co-delivery of minocycline and paclitaxel from injectable hydrogel for treatment of spinal cord injury

Spinal cord injury (SCI) induces pathological and inflammatory responses that create an inhibitory environment at the site of trauma, resulting in axonal degeneration and functional disability. Combination therapies targeting multiple aspects of the injury, will likely be more effective than single therapies to facilitate tissue regeneration after SCI. In this study, we designed a dual-delivery system consisting of a neuroprotective drug, minocycline hydrochloride (MH), and a neuroregenerative drug, paclitaxel (PTX), to enhance tissue regeneration in a rat hemisection model of SCI. For this purpose, PTX-encapsulated poly (lactic-co-glycolic acid) PLGA microspheres along with MH were incorporated into the alginate hydrogel. A prolonged and sustained release of MH and PTX from the alginate hydrogel was obtained over eight weeks. The obtained hydrogels loaded with a combination of both drugs or each of them alone, along with the blank hydrogel (devoid of any drugs) were injected into the lesion site after SCI (at the acute phase). Histological assessments showed that the dual-drug treatment reduced inflammation after seven days. Moreover, a decrease in the scar tissue, as well as an increase in neuronal regeneration was observed after 28 days in rats treated with dual-drug delivery system. Over time, a fast and sustained functional improvement was achieved in animals that received dual-drug treatment compared with other experimental groups. This study provides a novel dual-drug delivery system that can be developed to test for a variety of SCI models or neurological disorders.