The critical chemical and mechanical regulation of folic acid on neural engineering

Enabling Proregenerative Medical Devices via Citrate-Based Biomaterials: Transitioning from Inert to Regenerative Biomaterials

Regenerative medicine aims to restore tissue and organ function without the use of prosthetics and permanent implants. However, achieving this goal has been elusive, and the field remains mostly an academic discipline with few products widely used in clinical practice. From a materials science perspective, barriers include the lack of proregenerative biomaterials, a complex regulatory process to demonstrate safety and efficacy, and user adoption challenges. Although biomaterials, particularly biodegradable polymers, can play a major role in regenerative medicine, their suboptimal mechanical and degradation properties often limit their use, and they do not support inherent biological processes that facilitate tissue regeneration. As of 2020, nine synthetic biodegradable polymers used in medical devices are cleared or approved for use in the United States of America. Despite the limitations in the design, production, and marketing of these devices, this small number of biodegradable polymers has dominated the resorbable medical device market for the past 50 years. This perspective will review the history and applications of biodegradable polymers used in medical devices, highlight the need and requirements for regenerative biomaterials, and discuss the path behind the recent successful introduction of citrate-based biomaterials for manufacturing innovative medical products aimed at improving the outcome of musculoskeletal surgeries.

Efficacy and Mechanism Study of 6S-5-Methyltetrahydrofolate-Calcium Against Telencephalon Infarction Injury in Zebrafish Model of Ischemic Stroke

Ischemic stroke is a heterogeneous brain injury with complex pathophysiology and it is also a time sensitive neurological injury disease. At present, the treatment options for ischemic stroke are still limited. 6S-5-methyltetrahydrofolate-calcium (MTHF-Ca) is the calcium salt of the predominant form of dietary folate in circulation. MTHF-Ca has potential neuroprotective effect on neurocytes, but whether it can be used for ischemic stroke treatment remains unknown. We established zebrafish ischemic stroke model through photothrombotic method to evaluate the protective effect of MTHF-Ca on the ischemic brain injury of zebrafish. We demonstrated that MTHF-Ca reduced the brain damage by reducing motor dysfunction and neurobehavioral defects of zebrafish with telencephalon infarction injury. MTHF-Ca counteracted oxidative damages after Tel injury by increasing the activities of GSH-Px and SOD and decreasing the content of MDA. RNA-seq and RT-qPCR results showed that MTHF-Ca played a neuroprotective role by alleviating neuroinflammation, inhibiting blood coagulation, and neuronal apoptosis processes. Overall, we have demonstrated that MTHF-Ca has neuroprotective effect in ischemic stroke and can be used as a potential treatment for ischemic stroke.

Recent Progress in Advanced Polyester Elastomers for Tissue Engineering and Bioelectronics

Polyester elastomers are highly flexible and elastic materials that have demonstrated considerable potential in various biomedical applications including cardiac, vascular, neural, and bone tissue engineering and bioelectronics. Polyesters are desirable candidates for future commercial implants due to their biocompatibility, biodegradability, tunable mechanical properties, and facile synthesis and fabrication methods. The incorporation of bioactive components further improves the therapeutic effects of polyester elastomers in biomedical applications. In this review, novel structural modification methods that contribute to outstanding mechanical behaviors of polyester elastomers are discussed. Recent advances in the application of polyester elastomers in tissue engineering and bioelectronics are outlined and analyzed. A prospective of the future research and development on polyester elastomers is also provided.

Engineering human spinal microphysiological systems to model opioid-induced tolerance

pioids are commonly used for treating chronic pain. However, with continued use, they may induce tolerance and/or hyperalgesia, which limits therapeutic efficacy. The human mechanisms of opioid-induced tolerance and hyperalgesia are significantly understudied, in part, because current models cannot fully recapitulate human pathology. Here, we engineered novel human spinal microphysiological systems (MPSs) integrated with plug-and-play neural activity sensing for modeling human nociception and opioid-induced tolerance. Each spinal MPS consists of a flattened human spinal cord organoid derived from human stem cells and a 3D printed organoid holder device for plug-and-play neural activity measurement. We found that the flattened organoid design of MPSs not only reduces hypoxia and necrosis in the organoids, but also promotes their neuron maturation, neural activity, and functional development. We further demonstrated that prolonged opioid exposure resulted in neurochemical correlates of opioid tolerance and hyperalgesia, as measured by altered neural activity, and downregulation of μ-opioid receptor expression of human spinal MPSs. The MPSs are scalable, cost-effective, easy-to-use, and compatible with commonly-used well-plates, thus allowing plug-and-play measurements of neural activity. We believe the MPSs hold a promising translational potential for studying human pain etiology, screening new treatments, and validating novel therapeutics for human pain medicine.

E, K, B5, B6, and B9 vitamins and their specific immunological effects evaluated by flow cytometry

It has been proven that vitamins play an essential role in preventing certain diseases since ancient times. It is thus fruitless to approach the roles of vitamins without making reference to the techniques used in evaluating the effects of these micronutrients. Therefore, the aim of this paper was to summarize the immunological effects of E, K, B5, B6, and B9 vitamins evaluated by flow cytometry. Some of these significant effects were presented and discussed: (a) The role of vitamins E in the prevention and treatment of different types of cancer. (b) The properties of K vitamins in the development and maintenance of pheochromocytoma Cell Line 12 (PC12) cells in Parkinson's disease; (c) The improvement effect of vitamin B5 on the loss of bone mass in low estrogen conditions; (d) The anticancer role of vitamins B6. (e) The role of Vitamin B9 in the regulation of Treg cells. As such, the flow cytometry technique used to assess these properties is essential to evaluate the immunomodulatory effects of certain vitamins. The technique undergoes constant improvement which makes it possible to determine several parameters with a role in the modulation of the immune function and at the same time increase the accuracy of the methods that highlight them.

Engineering multifunctional bioactive citrate-based biomaterials for tissue engineering

Developing bioactive biomaterials with highly controlled functions is crucial to enhancing their applications in regenerative medicine. Citrate-based polymers are the few bioactive polymer biomaterials used in biomedicine because of their facile synthesis, controllable structure, biocompatibility, biomimetic viscoelastic mechanical behavior, and functional groups available for modification. In recent years, various multifunctional designs and biomedical applications, including cardiovascular, orthopedic, muscle tissue, skin tissue, nerve and spinal cord, bioimaging, and drug or gene delivery based on citrate-based polymers, have been extensively studied, and many of them have good clinical application potential. In this review, we summarize recent progress in the multifunctional design and biomedical applications of citrate-based polymers. We also discuss the further development of multifunctional citrate-based polymers with tailored properties to meet the requirements of various biomedical applications.

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Multifunctional bioactive citrate-based biomaterials have broad applications in regenerative medicine.

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Recent advances in multifunctional design and biomedical applications of citate-based polymers are summarized.

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Future challenge of citrate-based polymers in various biomedical applications are discussed.

Folic acid pretreatment and its sustained delivery for chondrogenic differentiation of MSCs

Dietary uptake of folic acid (FA) improves cartilage regeneration. In this work, we discovered that three days of FA treatment is highly effective for promoting chondrogenic differentiation of tonsil-derived mesenchymal stem cells (TMSCs). In a three-dimensional pellet culture, the levels of typical chondrogenic biomarkers, sulfated glycosaminoglycan, proteoglycan, type II collagen (COL II), SRY box transcription factor 9 (SOX 9), cartilage oligomeric matrix protein (COMP), and aggrecan (ACAN) increased significantly in proportion to FA concentration up to 30 μM. At the mRNA expression level, COL II, SOX 9, COMP, and ACAN increased 3.6-6.0-fold with FA treatment at 30 μM compared with the control system that did not receive FA treatment, and the levels with FA treatment were 1.6-2.5 times greater than those in the kartogenin-treated positive control system. FA treatment did not increase type I collagen α1 (COL I α1), an osteogenic biomarker which is a concern with most chondrogenic promoters. At the high FA concentration of 100 μM, significant decreases in chondrogenic biomarkers were observed, which might be related to DNA methylation. A thermogel system incorporating TMSCs and FA provided sustained release of FA over several days, similar to the FA treatment. The thermogel system confirmed the efficacy of FA in promoting chondrogenic promotion of TMSCs. The increased nuclear translocation of core-binding factor β subunit (CBFβ) and the runt-related transcription factor 1 (RUNX1) expression after FA treatment, together with molecular docking studies, suggest that the chondrogenic enhancement mechanism of FA is mediated by CBFβ and RUNX1.

Effective in vitro differentiation of adipose-derived stem cells into Schwann-like cells with folic acid supplementation

Peripheral nerve injury (PNI) after pelvic surgery is a common issue with a significant impact on patients. Autologous nerve grafting is the gold standard treatment for PNI, but this technique cannot be applied to fine nerve fibers in the pelvis. Schwann-like cell (SLC) differentiation is a novel therapeutic strategy for this clinical condition. However, the efficiency of SLC differentiation remains unsatisfactory. We modified an SLC differentiation protocol using adipose-derived stem cells (ADSCs) and folic acid. Morphology, gene expression and secretion of neurotrophic factors were examined to assess the differentiation quality and phenotypic characteristics. Our new modified protocol effectively induced a Schwann cell (SC) phenotype in ADSCs as assessed by morphology and expression of SC markers [S100 calcium-binding protein B (S100B), P < 0.01 ; p75 neurotrophic receptor (p75NTR), P < 0.05]. SLCs produced by the new protocol displayed a repair phenotype with decreased expression of ERBB2 and early growth response protein 2 (EGR2) / KROX20 (P < 0.01). Furthermore, our new protocol enhanced both mRNA expression and secretion of nerve growth factors by SLCs (P < 0.01). This protocol enhanced the SC characteristics and functions of ADSC-derived SLCs. This promising protocol requires further research and may contribute to SC-based nerve regeneration. J. Med. Invest. 68 : 347-353, August, 2021.

Folate Receptor Alpha Autoantibodies in Autism Spectrum Disorders: Diagnosis, Treatment and Prevention

Folate deficiency and folate receptor autoimmune disorder are major contributors to infertility, pregnancy related complications and abnormal fetal development including structural and functional abnormalities of the brain. Food fortification and prenatal folic acid supplementation has reduced the incidence of neural tube defect (NTD) pregnancies but is unlikely to prevent pregnancy-related complications in the presence of folate receptor autoantibodies (FRAb). In pregnancy, these autoantibodies can block folate transport to the fetus and in young children, folate transport to the brain. These antibodies are prevalent in neural tube defect pregnancies and in developmental disorders such as cerebral folate deficiency (CFD) syndrome and autism spectrum disorder (ASD). In the latter conditions, folinic acid treatment has shown clinical improvement in some of the core ASD deficits. Early testing for folate receptor autoantibodies and intervention is likely to result in a positive outcome. This review discusses the first identification of FRAb in women with a history of neural tube defect pregnancy and FRAb’s association with sub-fertility and preterm birth. Autoantibodies against folate receptor alpha (FRα) are present in about 70% of the children with a diagnosis of ASD, and a significant number of these children respond to oral folinic acid with overall improvements in speech, language and social interaction. The diagnosis of folate receptor autoimmune disorder by measuring autoantibodies against FRα in the serum provides a marker with the potential for treatment and perhaps preventing the pathologic consequences of folate receptor autoimmune disorder.

Mapping of folic acid in the children brainstem

Using highly specific antisera, the neuroanatomical distribution of folic acid (FA) and retinoic acid (RA) has been studied for the first time in the children brainstem. Neither immunoreactive structures containing RA nor immunoreactive fibers containing FA were found. FA-immunoreactive perikarya (fusiform, small/medium in size, one short dendrite) were only found in the pons in three regions: central gray, reticular formation, and locus coeruleus. The number of cell bodies decreased with age. In the first case studied (2 years), a moderate density of cell bodies was observed in the central gray and reticular formation, whereas a low density was found in the locus coeruleus. In the second case (6 years), a low density of these perikarya was observed in the central gray, reticular formation, and locus coeruleus. In the third case (7 years), a low density of FA-immunoreactive cell bodies was found in the central gray and reticular formation, whereas in the locus coeruleus no immunoreactive cell bodies were observed. The distribution of FA in the central nervous system of humans and monkeys is different and, in addition, in these species the vitamin was located in different parts of the nerve cells. The restricted distribution of FA suggests that the vitamin is involved in specific physiological mechanisms.

Aligned microfiber-induced macrophage polarization to guide schwann-cell-enabled peripheral nerve regeneration

Mechanistic understanding of the topological cues delivered by biomaterials in promotion of oriented tissue regeneration (e.g., peripheral nerve regrowth) remains largely elusive. Here, we engineered nerve conduits composed of oriented microfiber-bundle cores and randomly organized nanofiber sheaths to particularly interrogate the regulatory mechanism of microfiber orientation on promoted peripheral nerve regeneration. With comprehensive yet systematic analyses, we were able to elucidate the intricate cascade of biological responses associated with conduit-assisted nerve regrowth, i.e., oriented microfibers facilitated macrophage recruitment and subsequent polarization toward a pro-healing phenotype, which in turn promoted Schwann cell (SC) migration, myelinization and axonal extension. Pronounced improvement of nerve regeneration in rat sciatic nerve injury was evidenced with enhanced electrophysiologic function, sciatic functional index and alleviated muscle atrophy 3 months post-implantation. The obtained results offer essential insights on the topological regulation of biomaterials in functional nerve tissue regeneration via immune modulation.

Positive effect of Astragaloside IV on neurite outgrowth via talin-dependent integrin signaling and microfilament force

Integrin plays a prominent role in neurite outgrowth by transmitting both mechanical and chemical signals. Integrin expression is closely associated with Astragaloside IV (AS-IV), the main component extracted from Astragali radix, which has a positive effect on neural-protection. However, the relationship between AS-IV and neurite outgrowth has not been studied exhaustively to date. The present study investigated the underlying mechanism of AS-IV on neurite outgrowth. Longer neurites have been observed in SH-SY5Y cells or cortical neurons after AS-IV treatment. Furthermore, AS-IV not only increased the expression of integrin β but also activated it. The AS-IV-induced increased integrin activity was attributed to the integrin-activating protein talin. Application of the actin force probe showed that AS-IV led to an increase in intracellular microfilament force during neurite growth. Furthermore, in response to AS-IV, the microfilament force was regulated by talin and integrin activity during neurite growth. These results suggest that AS-IV has the ability to increase intracellular structural force and facilitate neurite elongation by integrin signaling, which highlights its therapeutic potential for neurite outgrowth.

Oral absorption enhancement of the amyloid-β oligomer eliminating compound RD2 by conjugation with folic acid

Amyloid-β (Aβ) plays a central role in the development and progression of Alzheimer's disease (AD) with Aβ oligomers representing the most toxic species. The all-d-enantiomeric peptide RD2, which recently successfully completed clinical phase I, specifically eliminates Aβ oligomers in vitro as well as in vivo and improves cognitive deficits in various transgenic AD mouse models even after oral administration. To further enhance the oral absorption of RD2, folic acid has been conjugated to the d-peptide promoting an endocytosis-mediated uptake via a folate receptor located in the intestine. Two different conjugation strategies were selected to obtain prodrugs with folic acid being cleaved after intestinal absorption releasing unmodified RD2 in order to enable RD2's unaltered systemic efficacy. Both conjugates remained stable in simulated gastrointestinal fluids. But only one of them was suitable as prodrug as it was cleaved to RD2 in vitro in human blood plasma and liver microsomes and in vivo in mice after intravenous injection leading to a systemic release of RD2. Furthermore, the conjugate's permeability in vitro and after oral administration in mice was strongly enhanced compared to unconjugated RD2 demonstrating the prodrug's functionality. However, the conjugate seemed to have impaired the mice's wellbeing shortly after oral administration possibly resulting from strain-specific hypersensitivity to folic acid. Nevertheless, we assume that the prodrug is actually non-toxic, especially in lower concentrations as verified by a cell viability test. Furthermore, lower dosages can be applied with unaltered efficacy due to its enhanced oral absorption.

Electrofabrication of flexible and mechanically strong tubular chitosan implants for peripheral nerve regeneration

The development of peripheral nerve tissue engineering requires a safe and reliable methodology to construct biodegradable conduits. Herein, a new type of chitosan-based nerve-guide hydrogel conduit (CNHC) with enhanced mechanical flexibility in the wet state was fabricated using a one-step electrofabrication technology. The formation of the chitosan conduit is a physical process which can be conducted in a mild water phase without toxic crosslinks. The current density during electrofabrication has a profound effect on the physical and structural properties of the conduits. Cytocompatibility results indicate that the CNHC can promote cell proliferation and adhesion. Functional and histological tests indicate that the CNHC has the ability to guide the growth of axons through the conduit to reach a distal stump, which is closely similar to the autograft group. Overall, the results of this study demonstrate that the CNHCs from electrofabrication have a great potential in peripheral nerve regeneration.

Diethylhexyl phthalate induces teratogenic effects through oxidative stress response in a chick embryo model

Diethylhexyl phthalate (DEHP) is known as a persistent environmental pollutant. However, the possible effects of DEHP on human neural tube defects (NTDs) remain elusive. We set out to investigate the exposure of DEHP in human and explore the association of DEHP and NTDs. The level of DEHP in maternal urine was measured and analyzed by GC-MS. To further validate the results in human NTDs, chick embryos were used as animal models. Viability, reactive oxygen species (ROS) level, oxidative stress indicators and apoptosis were detected in DEHP-treated chick embryos. Our research revealed that the detection ratio of positive DEHP and its metabolites in maternal urine were observed dramatically higher in NTDs population than that in normal controls (P < 0.01, P < 0.05, respectively). Moreover, DEHP treatment (10^-6 M) led to developmental toxicity in chick embryos via accelerating oxidative stress response and cell apoptosis, and changing the level of oxidative stress-related indicators. Moreover, high dose choline (100 μg/μl) could partially restrain the toxicity effects induced by DEHP. Our data collectively imply that the incidence of NTDs may closely associate with DEHP exposure, which disturbs the development of neural tubes by enhancing oxidative stress.

Modulation of Human Adipose Stem Cells' Neurotrophic Capacity Using a Variety of Growth Factors for Neural Tissue Engineering Applications: Axonal Growth, Transcriptional, and Phosphoproteomic Analyses In Vitro

We report on a potential strategy involving the exogenous neurotrophic factors (NTF) for enhancing the neurotrophic capacity of human adipose stem cells (ASC) in vitro. For this, ASC were stimulated for three days using NTF, i.e., nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), NT4, glial cell-derived neurotrophic factor (GDNF), and ciliary neurotrophic factor (CNTF). The resulting conditioned medium (CM) as well as individual NTF exhibited distinct effects on axonal outgrowth from dorsal root ganglion (DRG) explants. In particular, CM derived from NT3-stimulated ASC (CM-NT3-ASC) promoted robust axonal outgrowth. Subsequent transcriptional analysis of DRG cultures in response to CM-NT3-ASC displayed significant upregulation of STAT-3 and GAP-43. In addition, phosphoproteomic analysis of NT3-stimulated ASC revealed significant changes in the phosphorylation state of different proteins that are involved in cytokine release, growth factors signaling, stem cell maintenance, and differentiation. Furthermore, DRG cultures treated with CM-NT3-ASC exhibited significant changes in the phosphorylation levels of proteins involved in tubulin and actin cytoskeletal pathways, which are crucial for axonal growth and elongation. Thus, the results obtained at the transcriptional, proteomic, and cellular level reveal significant changes in the neurotrophic capacity of ASC following NT3 stimulation and provide new options for improving the axonal growth-promoting potential of ASC in vitro.

Mechanosensing by Gli1+ cells contributes to the orthodontic force-induced bone remodelling

Objectives

Gli1⁺ cells have received extensive attention in tissue homeostasis and injury mobilization. The aim of this study was to investigate whether Gli1⁺ cells respond to force and contribute to bone remodelling.

Materials and methods

We established orthodontic tooth movement (OTM) model to assess the bone response for mechanical force. The transgenic mice were utilized to label and inhibit Gli1⁺ cells, respectively. Additionally, mice that conditional ablate Yes‐associated protein (Yap) in Gli1⁺ cells were applied in the present study. The tooth movement and bone remodelling were analysed.

Results

We first found Gli1⁺ cells expressed in periodontal ligament (PDL). They were proliferated and differentiated into osteoblastic cells under tensile force. Next, both pharmacological and genetic Gli1 inhibition models were utilized to confirm that inhibition of Gli1⁺ cells led to arrest of bone remodelling. Furthermore, immunofluorescence staining identified classical mechanotransduction factor Yap expressed in Gli1⁺ cells and decreased after suppression of Gli1⁺ cells. Additionally, conditional ablation of Yap gene in Gli1⁺ cells inhibited the bone remodelling as well, suggesting Gli1⁺ cells are force‐responsive cells.

Conclusions

Our findings highlighted that Gli1⁺ cells in PDL directly respond to orthodontic force and further mediate bone remodelling, thus providing novel functional evidence in the mechanism of bone remodelling and first uncovering the mechanical responsive property of Gli1⁺ cells.

Fibronectin is a smart adhesive that both influences and responds to the mechanics of early spinal column development

An extracellular matrix of Fibronectin adheres the neural tube to the two flanking columns of paraxial mesoderm and is required for normal vertebrate development. Here, we find that the bilaterally symmetric interfaces between the zebrafish neural tube and paraxial mesoderm function as optimally engineered adhesive lap joints with rounded edges, graded Fibronectin ‘adhesive’ and an arced adhesive spew filet. Fibronectin is a ‘smart adhesive’ that remodels to the lateral edges of the neural tube-paraxial mesoderm interfaces where shear stress is highest. Fibronectin remodeling is mechanically responsive to contralateral variation morphogenesis, and Fibronectin-mediated inter-tissue adhesion is required for bilaterally symmetric morphogenesis of the paraxial mesoderm. Strikingly, however, perturbation of the Fibronectin matrix rescues the neural tube convergence defect of cadherin 2 mutants. Therefore, Fibronectin-mediated inter-tissue adhesion dynamically coordinates bilaterally symmetric morphogenesis of the vertebrate trunk but predisposes the neural tube to convergence defects that lead to spina bifida.

In embryos, the spinal cord starts out as a flat sheet of cells that curls up to form a closed cylinder called the neural tube. The folding tube is attached to the surrounding tissues through an extracellular matrix of proteins and sugars. Overlapping strands of a protein from the extracellular matrix called Fibronectin connect the neural tube to adjacent tissues, like a kind of biological glue. However, it remained unclear what effect this attachment had on the embryonic development of the spinal cord.

Connecting two overlapping objects with glue to form what is known as an ‘adhesive lap joint’ is common in fields such as woodworking and aeronautical engineering. The glue in these joints comes under shearing stress whenever the two objects it connects try to pull apart. But, thanks to work in engineering, it is possible to predict how different joints will perform under tension. Now, Guillon et al. have deployed these engineering principles to shed light on neural tube development.

Using zebrafish embryos and computational models, Guillon et al. investigated what happens when the strength of the adhesive lap joints in the developing spine changes. This revealed that Fibronectin works like a smart adhesive: rather than staying in one place like a conventional glue, it moves around. As the neural tube closes, cells remodel the Fibronectin, concentrating it on the areas under the highest stress. This seemed to both help and hinder neural tube development. On the one hand, by anchoring the tube equally to the left and right sides of the embryo, the Fibronectin glue helped the spine to develop symmetrically. On the other hand, the strength of the adhesive lap joints made it harder for the neural tube to curl up and close.

If the neural tube fails to close properly, it can lead to birth defects like spina bifida. One of the best-known causes of these birth defects in humans is a lack of a vitamin known as folic acid. Cell culture experiments suggest that this might have something to do with the mechanics of the cells during development. It may be that faulty neural tubes could close more easily if they were able to unglue themselves from the surrounding tissues. Further use of engineering principles could shed more light on this idea in the future.

One-Stop Microfluidic Assembly of Human Brain Organoids To Model Prenatal Cannabis Exposure

Prenatal cannabis exposure (PCE) influences human brain development, but it is challenging to model PCE using animals and current cell culture techniques. Here, we developed a one-stop microfluidic platform to assemble and culture human cerebral organoids from human embryonic stem cells (hESC) to investigate the effect of PCE on early human brain development. By incorporating perfusable culture chambers, air-liquid interface, and one-stop protocol, this microfluidic platform can simplify the fabrication procedure and produce a large number of organoids (169 organoids per 3.5 cm × 3.5 cm device area) without fusion, as compared with conventional fabrication methods. These one-stop microfluidic assembled cerebral organoids not only recapitulate early human brain structure, biology, and electrophysiology but also have minimal size variation and hypoxia. Under on-chip exposure to the psychoactive cannabinoid, Δ-9-tetrahydrocannabinol (THC), cerebral organoids exhibited reduced neuronal maturation, downregulation of cannabinoid receptor type 1 (CB1) receptors, and impaired neurite outgrowth. Moreover, transient on-chip THC treatment also decreased spontaneous firing in these organoids. This one-stop microfluidic technique enables a simple, scalable, and repeatable organoid culture method that can be used not only for human brain organoids but also for many other human organoids including liver, kidney, retina, and tumor organoids. This technology could be widely used in modeling brain and other organ development, developmental disorders, developmental pharmacology and toxicology, and drug screening.

Augmented peripheral nerve regeneration through elastic nerve guidance conduits prepared using a porous PLCL membrane with a 3D printed collagen hydrogel

Longitudinally oriented, 3D printed collagen hydrogel-grafted elastic nerve guidance conduits to promote nerve regeneration in peripheral nerve defects.

Folic Acid Decreases Astrocyte Apoptosis by Preventing Oxidative Stress-Induced Telomere Attrition

Astrocytes are the most widely distributed cells in the brain, and astrocyte apoptosis may play an important role in the pathogenesis of neurodegenerative diseases. Folate is required for the normal development of the nervous system, but its effect on astrocyte apoptosis is unclear. In this study, we hypothesized that folic acid (the therapeutic form of folate) decreases astrocyte apoptosis by preventing oxidative stress-induced telomere attrition. Primary cultures of astrocytes were incubated for 12 days with various concentrations of folic acid (0-40 μmol/L), then cell proliferation, apoptosis, intracellular folate concentration, intracellular homocysteine (Hcy) concentration, intracellular reactive oxygen species (ROS) levels, telomeric DNA oxidative damage, and telomere length were determined. The results showed that folic acid deficiency decreased intracellular folate, cell proliferation, and telomere length, whereas it increased Hcy concentration, ROS levels, telomeric DNA oxidative damage, and apoptosis. In contrast, folic acid dose-dependently increased intracellular folate, cell proliferation, and telomere length but it decreased Hcy concentration, ROS levels, telomeric DNA oxidative damage, and apoptosis. In conclusion, folic acid inhibited apoptosis in astrocytes. The underlying mechanism for this protective effect may be that folic acid decreased oxidative stress and thereby prevented telomeric DNA oxidative damage and telomere attrition.

Enabling biodegradable functional biomaterials for the management of neurological disorders

An increasing number of patients are being diagnosed with neurological diseases, but are rarely cured because of the lack of curative therapeutic approaches. This situation creates an urgent clinical need to develop effective diagnosis and treatment strategies for repair and regeneration of injured or diseased neural tissues. In this regard, biodegradable functional biomaterials provide promising solutions to meet this demand owing to their unique responsiveness to external stimulation fields, which enable neuro-imaging, neuro-sensing, specific targeting, hyperthermia treatment, controlled drug delivery, and nerve regeneration. This review discusses recent progress in the research and development of biodegradable functional biomaterials including electroactive biomaterials, magnetic materials and photoactive biomaterials for the management of neurological disorders with emphasis on their applications in bioimaging (photoacoustic imaging, MRI and fluorescence imaging), biosensing (electrochemical sensing, magnetic sensing and opical sensing), and therapy strategies (drug delivery, hyperthermia treatment, and tissue engineering). It is expected that this review will provide an insightful discussion on the roles of biodegradable functional biomaterials in the diagnosis and treatment of neurological diseases, and lead to innovations for the design and development of the next generation biodegradable functional biomaterials.

Pigments and vitamins from plants as functional ingredients: Current trends and perspectives

The food manufacturing industry has increasingly focused in the development of wholesome and safer products, including certified labeled "super foods," "healthy foods" and "functional foods," which are currently under great demand worldwide. Plant pigments and vitamins are amidst the most common additives incorporated to foodstuff, not only for improving their nutritional status but also for coloration, preservation, and even therapeutic purposes. The recovery of pigments from agro industrial wastes using green emerging approaches is a current trend and clearly the best alternative to ensure their sustainable obtainment and make these ingredients more popular, although still full of challenging aspects. Stability and bioavailability limitations of these active molecules in food matrices have been increasingly studied, and a number of methods have been proposed to minimize these issues, among which the incorporation of a co-pigment, exclusion of O₂ during processing and storage, and above all, microencapsulation and nanoencapsulation techniques. The most recent advances and challenges in the application of natural pigments and vitamins in functional foods, considering only reports of the last 5 years, were the focus of this chapter.

Tissue Engineering Therapies Based on Folic Acid and Other Vitamin B Derivatives. Functional Mechanisms and Current Applications in Regenerative Medicine

B-vitamins are a group of soluble vitamins which are cofactors of some of the enzymes involved in the metabolic pathways of carbohydrates, fats and proteins. These compounds participate in a number of functions as cardiovascular, brain or nervous systems. Folic acid is described as an accessible and multifunctional niche component that can be used safely, even combined with other compounds, which gives it high versatility. Also, due to its non-toxicity and great stability, folic acid has attracted much attention from researchers in the biomedical and bioengineering area, with an increasing number of works directed at using folic acid and its derivatives in tissue engineering therapies as well as regenerative medicine. Thus, this review provides an updated discussion about the most relevant advances achieved during the last five years, where folic acid and other vitamins B have been used as key bioactive compounds for enhancing the effectiveness of biomaterials' performance and biological functions for the regeneration of tissues and organs.