Secretome of stem cells from human exfoliated deciduous teeth (SHED) and its extracellular vesicles improves keratinocytes migration, viability, and attenuation of H2 O2 -induced cytotoxicity

Therapies for wound healing using the secretome and extracellular vesicles (EVs) of mesenchymal stem/stromal cells have been shown to be successful in preclinical studies. This study aimed to characterise the protein content of the secretome from stem cells from human exfoliated deciduous teeth (SHED) and analyse the in vitro effects of SHED-conditioned medium (SHED-CM) and SHED extracellular vesicles (SHED-EVs) on keratinocytes. EVs were isolated and characterised. The keratinocyte viability and migration of cells treated with SHED-EVs and conditioned medium (CM) were evaluated. An HaCaT apoptosis model induced by H2 O2 in vitro was performed with H2 O2 followed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and live/dead assays. Finally, the expression of vascular endothelial growth factor (VEGF) in keratinocytes treated with secretome and EVs was evaluated by immunofluorescence staining and confirmed with RT-qPCR. SHED-EVs revealed a cup-shaped morphology with expression of the classical markers for exosomes CD9 and CD63, and a diameter of 181 ± 87 nm. The internalisation of EVs by HaCaT cells was confirmed by fluorescence microscopy. Proteomic analysis identified that SHED-CM is enriched with proteins related to stress response and development, including cytokines (CXCL8, IL-6, CSF1, CCL2) and growth factors (IGF2, MYDGF, PDGF). The results also indicated that 50% CM and 0.4-0.6 μg/mL EVs were similarly efficient for improving keratinocyte viability, migration, and attenuation of H2 O2 -induced cytotoxicity. Additionally, expression of VEGF on keratinocytes increased when treated with SHED secretome and EVs. Furthermore, VEGF gene expression in keratinocytes increased significantly when treated with SHED secretome and EVs. Both SHED-CM and SHED-EVs may therefore be promising therapeutic tools for accelerating re-epithelialization in wound healing.

Cell Electrospinning: a Review of Materials and Methodologies for Biofabrication

The process of electrohydrodynamic living cell microencapsulation inside a scaffold during the electrospinning (ES) process is called cell electrospinning (CE). Several studies demonstrate the feasibility of using cell electrospinning for biomedical applications, allowing for the direct biofabrication of living cells to be encapsulated in fibers for the formation of active biological scaffolds. In this review, a comprehensive overview of the materials and methodologies used in cell electrospinning, as well as their biomedical application in tissue engineering, is provided. Cell ES represents an innovative technique for automated application in regenerative medicine.

Bilayer scaffold from PLGA/fibrin electrospun membrane and fibrin hydrogel layer supports wound healingin vivo

Hybrid scaffolds from natural and synthetic polymers have been widely used due to the complementary nature of their physical and biological properties. The aim of the present study, therefore, has been to analyzein vivoa bilayer scaffold of poly(lactide-co-glycolide)/fibrin electrospun membrane and fibrin hydrogel layer on a rat skin model. Fibroblasts were cultivated in the fibrin hydrogel layer and keratinocytes on the electrospun membrane to generate a skin substitute. The scaffolds without and with cells were tested in a full-thickness wound model in Wistar Kyoto rats. The histological results demonstrated that the scaffolds induced granulation tissue growth, collagen deposition and epithelial tissue remodeling. The wound-healing markers showed no difference in scaffolds when compared with the positive control. Activities of antioxidant enzymes were decreased concerning the positive and negative control. The findings suggest that the scaffolds contributed to the granulation tissue formation and the early collagen deposition, maintaining an anti-inflammatory microenvironment.

Easy-to-Assembly System for Decellularization and Recellularization of Liver Grafts in a Bioreactor

Decellularization of organs creates an acellular scaffold, ideal for being repopulated by cells. In this work, a low-cost perfusion system was created to be used in the process of liver decellularization and as a bioreactor after recellularization. It consists of a glass chamber to house the organ coupled to a peristaltic pump to promote liquid flow through the organ vascular tree. The rats' liver decellularization was made with a solution of sodium dodecyl sulfate. The recellularization was made with 10⁸ mesenchymal stromal/stem cells and cultivated for seven days. The decellularized matrices showed an absence of DNA while preserving the collagen and glycosaminoglycans quantities, confirming the efficiency of the process. The functional analyses showed a rise in lactate dehydrogenase levels occurring in the first days of the cultivation, suggesting that there is cell death in this period, which stabilized on the seventh day. Histological analysis showed conservation of the collagen web and some groups of cells next to the vessels. It was possible to establish a system for decellularization and a bioreactor to use for the recellularization method. It is easy to assemble, can be ready to use in little time and be easily sterilized.

Rosmarinic and chlorogenic acid, isolated from ferns, suppress stem cell damage induced by hydrogen peroxide

OBJECTIVES

Evaluating the effects of rosmarinic (RA) and cryptochlorogenic (CGA) acids isolated from Blechnum binervatum extract on stem cell viability, toxicity and the protective effect on oxidative cell damage.

METHODS

MTT and LDH methods were employed, using stem cells from teeth. RA and CGA were evaluated at 100, 250 and 500 µM. The negative effect of hydrogen peroxide (H2O2) (200-2200 µM) and the capacity of RA and CGA (10-100 µM) as protective agents were also evaluated. DAPI followed by fluorescent microscopy was employed to photograph the treated and untreated cells.

KEY FINDINGS

At all tested concentrations, RA and CGA demonstrated the ability to maintain cell viability, and with no cytotoxic effects on the treated stem cells. RA also induced an increase of the cell viability and a reduction in cytotoxicity. H2O2 (1400 µM) induced >50% of cytotoxicity, and both compounds were capable of suppressing H2O2 damage, even at the lowest concentration. At 100 µM, in H2O2 presence, total cell viability was observed through microscope imaging.

CONCLUSIONS

These findings contribute to the continued research into natural substances with the potential for protecting cells against oxidative injury, with the consideration that RA and CGA are useful in the regeneration of damaged stem cells.

The role of stem cell-derived exosomes in the repair of cutaneous and bone tissue

Exosomes are extracellular vesicles secreted by various cell types, which play important roles in physiological processes. In particular, stem cell-derived exosomes have been shown to play crucial functions in intercellular communication during the tissue healing process. This review summarizes the effects of exosomes derived from different stem cell sources on the repair of cutaneous and bone tissue, focusing on the different pathways that could be involved in the regeneration process. The biogenesis, isolation, and content of exosomes have also been discussed. The effectiveness of exosomes is broadly demonstrated for skin and bone regeneration in animal models, supporting the basis for clinical translation of exosomes as a ready-to-use cell-free therapeutic for skin and bone regeneration.

Dissolution, bioactivity behavior, and cytotoxicity of 19.58Li2 O·11.10ZrO2 ·69.32SiO2 glass-ceramic

Glass and bioactive glass-ceramic can be used in several applications. In bone growth where good bone/biomaterial adhesion was required, bioactive coatings for implants can improve bone formation. The glass and glass-ceramics of the LZS (Li₂ O-ZrO₂ -SiO₂ ) system are very interesting because of their mechanical, electrical, and thermal properties. Very recently, their biological response in contact with human osteoblast has been evaluated. However, despite several initiatives, there are still no studies that systematically assess this system's bioactivity, dissolution, and cytotoxicity in vitro. This work aims to investigate the dissolution, bioactivity behavior, and cytotoxicity of LZS glass-ceramic. LZS glass-ceramics were produced from SiO₂ , Li₂ CO_3, and ZrSiO₄ by melting followed by quenching. The obtained glass frits were milled and uniaxially pressed and heat-treated at 800 and 900°C and submitted to physical-chemical, structural and mechanical characterization. Their dissolution behavior was studied in Tris-HCl, while bioactivity was performed in simulated solution body fluid (SBF). The cytotoxicity test was performed using glass-ceramic in direct contact with mesenchymal stem/stromal cells (SC) isolated from human exfoliated deciduous teeth. Structural and microstructural analyzes confirmed bioactivity. The results show that it was possible to produce bioactive glass-ceramic from LZS, proven by the formation of new calcium phosphate structures such as hydroxyapatite on the surface of the samples after exposure to SBF. The SC viability test performed indicated that the materials were not cytotoxic at 0.25, 0.5, and 1.0 mg/ml. The glass-ceramic system under study is very promising for a medicinal application that requires bioactivity and/or biocompatibility for bone regeneration.

Poly (lactide-co-glycolide) (PLGA) Scaffold Induces Short-term Nerve Regeneration and Functional Recovery Following Sciatic Nerve Transection in Rats

Peripheral nerve injury is an important cause of incapability and has limited available treatment. Autologous donor nerve implant is the golden standard treatment, however, may cause secondary deficits. Stem cells show positive results in preclinical settings, preserving tissue and function. We tested the efficacy of stem cells derived from human exfoliated deciduous teeth seeded in poly (lactide-co-glycolide) scaffolds in sciatic nerve transection model. Seventy-two adult male Wistar rats had 7-mm nerve gap bridge using scaffolds with (or without) stem cells. Animals were randomly divided into: sham-operated; sham-operated without scaffold; sham-operated + scaffold + stem cells; sciatic transection + no treatment; sciatic transection + acellular scaffolds; sciatic transection + scaffold + stem cells. Sciatic Functional Index and Ladder Rung Walking tests were performed before (-1), 14 and 28 days after surgery. Morphometric nerve measurement and muscle weights were assessed. Scaffolds with stem cells improved function in Sciatic Functional Index. Acellular scaffold was effective, promoting functional recovery and nerve regeneration following nerve injury. Scaffolds provide better nerve regeneration and functional recovery after sciatic transection. Despite cell therapy promoting faster recovery after sciatic transection in the Sciatic Index Score, stem cells did not improve functional and morphological recovery after nerve injury. This is the first study testing the potential use of scaffolds combined with stem cells in the early stages after injury. Scaffolds with stem cells could accelerate nerve recovery and favor adjuvant therapies, evidencing the need for further studies to increase the knowledge about stem cells' mechanisms.

Correction to: Stem Cells from Human Exfoliated Deciduous Teeth Modulate Early Astrocyte Response after Spinal Cord Contusion

The authors hereby declare that the Figure 4 in page eight of the paper "Stem cells from human exfoliated deciduous teeth modulate early astrocyte response after spinal cord contusion" authored by Fabrício Nicola and colleagues (DOI: 10.1007/s12035-018-1127-4) was mistakenly included.

Stem Cells from Human Exfoliated Deciduous Teeth Modulate Early Astrocyte Response after Spinal Cord Contusion

The transplantation of stem cells from human exfoliated deciduous teeth (SHED) has been studied as a possible treatment strategy for spinal cord injuries (SCIs) due to its potential for promoting tissue protection and functional recovery. The aim of the present study was to investigate the effects of the early transplantation of SHED on glial scar formation and astrocytic reaction after an experimental model of SCI. Wistar rats were spinalized using the NYU Impactor. Animals were randomly distributed into three groups: control (naive) (animal with no manipulation); SCI (receiving laminectomy followed by SCI and treated with vehicle), and SHED (SCI rat treated with intraspinal SHED transplantation, 1 h after SCI). In vitro investigation demonstrated that SHED were able to express mesenchymal stem cells, vimentin and S100B markers, related with neural progenitor and glial cells, respectively. The acute SHED transplantation promoted functional recovery, measured as from the first week after spinal cord contusion by Basso, Beattie, and Bresnahan scale. Twenty-four and 48 h after lesion, flow cytometry revealed a spinal cord vimentin⁺ cells increment in the SHED group. The increase of vimentin⁺ cells was confirmed by immunofluorescence. Moreover, the bioavailability of astrocytic proteins such as S100B and Kir4.1 shown to be increased in the spinal cord of SHED group, whereas there was a glial scar reduction, as indicated by ELISA and Western blot techniques. The presented results support that SHED act as a neuroprotector agent after transplantation, probably through paracrine signaling to reduce glial scar formation, inducing tissue plasticity and functional recovery.

Identification of compounds from non-polar fractions of Blechnum spp and a multitarget approach involving enzymatic modulation and oxidative stress

OBJECTIVES

The hexane (HEX) and dichloromethane (DCM) fractions from Blechnum binervatum, Blechnum brasiliense and Blechnum occidentale were studied about phytochemicals and biological properties using multitarget approach.

METHODS

The chemical composition was performed by gas chromatography coupled with mass spectrometry detector (GC-MS) analysis. Antioxidant capacity was evaluated against free radicals and on lipid peroxidation. Monoamine oxidases (MAO) and cholinesterases enzymatic modulation, as well as effects on rat and human cells, were assessed.

KEY FINDINGS

The CG-MS analysis allowed the identification of a non-polar compound series, being neophytadiene the major constituent in all DCM fractions and in HEX fractions from B. binervatum and B. occidentale. In B. brasiliense HEX fraction, β-sitosterol was the main compound. In general, B. brasiliense DCM fraction presented the highest antioxidant activity, with IC₅₀ values around 9, 2 and 1.2 times lower than those found for the other species, against HO˙, NO˙ and on lipid peroxidation, respectively. Regarding enzyme modulations, B. brasiliense DCM fraction presented higher MAO-A inhibition (IC₅₀ : 31.83 μg/ml), with a better selectivity index (SI MAO-A/MAO-B: 6.77). The lack of harmful effects was observed in rat cells, also highlighted in the stem cells for all Blechnum samples.

CONCLUSION

These findings encourage the search for multibinding natural products, mainly from B. brasiliense DCM fraction.

In vitro Antioxidant and Enzymatic Approaches to Evaluate Neuroprotector Potential of Blechnum Extracts without Cytotoxicity to Human Stem Cells

BACKGROUND

Investigation of selected plant extracts on multi-targets related to neurodegeneration, such as monoamine oxidases (MAO), cholinesterase enzymes, and antioxidant activities (AOA) is a useful tool for identification of new scaffolds.

OBJECTIVE

This work investigated biological effects of three Blechnum methanol extracts from Brazil and chemical profile of the most active sample.

MATERIALS AND METHODS

AOA included scavenging of hydroxyl and nitric oxide radicals, also lipid peroxidation inhibition. Enzymatic modulation of Blechnum binervatum, Blechnum brasiliense, and Blechnum occidentale extracts on MAO and cholinesterases was conducted. Moreover, total phenol content was performed with all samples, and high-performance liquid chromatography-diode array detection mass spectrometry HPLC-DAD-MS analysis was carried out with B. brasiliense. Possible toxic effects were evaluated on Wistar rats polymorphonuclear cells (PMN) and human stem cells.

RESULTS

B. brasiliense extract presented the highest phenolic amount (9.25 g gallic acid equivalent/100 g extract) and lowest IC50 values (112.3 ± 2.61 and 176.1 ± 1.19 μg/mL) against hydroxyl radicals and on lipid peroxidation, respectively, showing strong AO effects. On nitric oxide assay and cholinesterase inhibition, all extracts were considered inactive. MAO-A selective action was evidenced, being B. brasiliense powerful against this enzyme (IC50: 72.7 μg/mL), followed by B. occidentale and B. binervatum (IC50: 130.85 and 165.2 μg/mL). No cytotoxic effects were observed on PMN and human stem cells treated with Blechnum extracts. HPLC-DAD-MS analysis of B. brasiliense allowed the identification of chlorogenic and rosmarinic acids.

CONCLUSION

Our results especially highlight B. brasiliense, with pronounced phenols content and strong effects on selected targets related to neurodegeneration, being characterized as a natural safe source of bioactive hydroxycinnamic acids.

SUMMARY

Blechnum crude extracts showed high phenolic amounts and valuable IC50 values on targets related with neurodegenerative disordersBlechnum brasiliense was the most active sample, with strong radical scavenging and lipid peroxidation inhibition, also with monoamine oxidases: A selective modulationNo cytotoxic effects were observed on polymorphonuclear cells rat cells and human stem cells treated with Blechnum extractsHigh-performance liquid chromatography-diode array detection-mass spectrometry analysis of Blechnum brasiliense allowed the identification of hydroxycinnamic derivatives: Chlorogenic and rosmarinic acids. Abbreviations used: IC50: half maximal inhibitory concentration; MAO: monoamine oxidase; MAO-A: monoamine oxidase isoform A; MAO-B: monoamine oxidase isoform B; HO•: hydroxyl radical.

Impact of Storage at -80°C on Encapsulated Liver Spheroids After Liquid Nitrogen Storage

For many bioengineered tissues to have practical clinical application, cryopreservation for use on demand is essential. This study examined different thermal histories on warming and short holding periods at different subzero temperatures on subsequent functional recoveries of alginate encapsulated liver spheroids (ELS) for use in a bioartificial liver device. This mimicked transport at liquid nitrogen (−196°C) or dry ice (∼−80°C) temperatures. Holding at −80°C on warming after −196°C storage resulted in ELS expressing significant (p < 0.001) damage compared with direct thaw from liquid nitrogen, with viable cell number falling from 74.0 ± 8.4 million viable cells/mL without −80°C storage to 1.9 ± 0.6 million viable cells/mL 72 h post-thaw after 8 days storage at −80°C. Even 1 day at −80°C after −196°C storage resulted in lower viability (down 21% 24 h post-thaw), viable cell count (down 29% 24 h post-thaw), glucose, and alpha-1-fetoprotein production (reduced by 59% and 95% 24 h from 1 day post-thaw, respectively). Storage at −80°C was determined to be harmful only during the warming cycle. Chemical measurements of the alginate component of ELS were unchanged by cryogenic exposure in either condition.

A phosphodiesterase 4-controlled switch between memory extinction and strengthening in the hippocampus

Established fear-related memories can undergo phenomena such as extinction or reconsolidation when recalled. Extinction probably involves the creation of a new, competing memory trace that decreases fear expression, whereas reconsolidation can mediate memory maintenance, updating, or strengthening. The factors determining whether retrieval will initiate extinction, reconsolidation, or neither of these two processes include training intensity, duration of the retrieval session, and age of the memory. However, previous studies have not shown that the same behavioral protocol can be used to induce either extinction or reconsolidation and strengthening, depending on the pharmacological intervention used. Here we show that, within an experiment that leads to extinction in control rats, memory can be strengthened if rolipram, a selective inhibitor of phosphodiesterase type 4 (PDE4), is administered into the dorsal hippocampus immediately after retrieval. The memory-enhancing effect of rolipram lasted for at least 1 week, was blocked by the protein synthesis inhibitor anisomycin, and did not occur when drug administration was not paired with retrieval. These findings indicate that the behavioral outcome of memory retrieval can be pharmacologically switched from extinction to strengthening. The cAMP/protein kinase A (PKA) signaling pathway might be a crucial mechanism determining the fate of memories after recall.

Impairment of object recognition memory by rapamycin inhibition of mTOR in the amygdala or hippocampus around the time of learning or reactivation

The role of the basolateral complex of the amygdala (BLA) in recognition memory remains poorly understood. The mammalian target of rapamycin (mTOR) in the BLA and other brain areas has been implicated in synaptic plasticity and memory. We have recently shown that mTOR signaling in both the BLA and the dorsal hippocampus (DH) is required for formation and reconsolidation of inhibitory avoidance, a fear-motivated memory task. Here we examined the effects of infusions of the mTOR inhibitor rapamycin into the BLA before or after either training or reactivation on retention of novel object recognition (NOR) memory in rats, and compared the effects with those obtained using intra-DH infusions. Male Wistar rats received bilateral infusions of vehicle or rapamycin into the BLA or DH before or after NOR training or reactivation. Rapamycin impaired NOR retention tested 24h after training when given either before or immediately after training into the BLA or DH. Rapamycin also impaired retention measured 24h after reactivation when infused before reactivation into the BLA or DH, or immediately after reactivation into the BLA, but not when given 6h after reactivation into either the BLA or DH. The results suggest that mTOR signaling in the BLA and DH is involved in NOR memory formation and stabilization.

Memory impairment induced by brain iron overload is accompanied by reduced H3K9 acetylation and ameliorated by sodium butyrate

Iron accumulation in the brain has been associated to the pathogenesis of neurodegenerative disorders. We have previously demonstrated that iron overload in the neonatal period results in severe and persistent memory deficits in adult rats. Alterations in histone acetylation have been associated with memory deficits in models of neurological disorders. Here we examine histone acetylation in the brain and the effects of the histone deacetylase inhibitor (HDACi) sodium butyrate (NaB) on memory in the neonatal iron overload model in rats. Rats received vehicle or 30.0-mg/kg Fe⁺² orally at postnatal days 12-14. When animals reached adulthood, they were given training in either novel object recognition or inhibitory avoidance. Histone acetylation in the dorsal hippocampus and the effects of NaB were examined in separate sets of rats. Iron overload led to a reduction in H3 lysine 9 acetylation in the hippocampus, without affecting the acetylation of other H3 and H4 lysine residues. A single systemic injection of NaB (1.2 g/kg) immediately after training ameliorated iron-induced memory impairments. The results suggest that a reduction in H3K9 acetylation might play a role in iron-induced memory impairment and support the view that HDACis can rescue memory dysfunction in models of brain disorders.

Effect of mangiferin, a naturally occurring glucoxylxanthone, on fear memory in rats

Mangiferin (1,3,6,7-tetrahydroxy-2-[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl] -xanthen-9-one, CAS 4773-96-0), a naturally occurring glucosylxanthone, is widely distributed in higher plants and a constituent of folk medicine. In the present study the effect of systemic administration of mangiferin on behavioural outcomes of neurological function in normal rats was investigated. A single intraperitoneal injection of mangiferin (10, 50 and 100 mg/kg body weight) immediately post-training produced an impairment of long-term memory for aversive training and a reduced freezing in a dose independent manner, when given immediately post-training. The administration of mangiferin 6 h post-training did not affect fear memory. The results indicate that mangiferin might induce deficits of emotionally motivated memory.

Posttraining systemic administration of the histone deacetylase inhibitor sodium butyrate ameliorates aging-related memory decline in rats

Here we show that a systemic injection of the histone deacetylase inhibitor (HDACi) sodium butyrate (NaB) ameliorated an aging-associated deficit in object recognition memory in rats when the injection was given immediately, but not 6h after training. NaB had no effect in younger rats with normal memory retention. The results indicate that HDACis can ameliorate aging-related memory impairments by influencing the early consolidation phase of memory formation.

A Valepotriate Fraction of Valeriana glechomifolia Shows Sedative and Anxiolytic Properties and Impairs Recognition But Not Aversive Memory in Mice

Plants of the genus Valeriana (Valerianaceae) are used in traditional medicine as a mild sedative, antispasmodic and tranquilizer in many countries. This study was undertaken to explore the neurobehavioral effects of systemic administration of a valepotriate extract fraction of known quantitative composition of Valeriana glechomifolia (endemic of southern Brazil) in mice. Adult animals were treated with a single intraperitoneal injection of valepotriate fraction (VF) in the concentrations of 1, 3 or 10 mg kg⁻¹, or with vehicle in the pre-training period before each behavioral test. During the exploration of an open field, mice treated with 10 mg kg⁻¹ of VF showed reduced locomotion and exploratory behavior. Although overall habituation sessions for locomotion and exploratory behavior among vehicle control and doses of VF were not affected, comparison between open-field and habituation sessions within each treatment showed that VF administration at 1 and 10 mg kg⁻¹ impaired habituation. In the elevated plus-maze test, mice treated with VF (10 mg kg⁻¹) showed a significant increase in the percentage of time spent in the open arms without significant effects in the number of total arm entries. VF at 3 mg kg⁻¹ produced an impairment of novel-object recognition memory. In contrast, VF did not affect fear-related memory assessed in an inhibitory avoidance task. The results indicate that VF can have sedative effects and affect behavioral parameters related to recognition memory.

Control of development and valepotriate production by auxins in micropropagated Valeriana glechomifolia

Valeriana glechomifolia is a plant species endemic to southern Brazil that accumulates valepotriates, which are terpene derivatives, in all of its organs. Valepotriates are the presumed sedative generic components of the pharmaceutically used species of Valeriana. The influence of various concentrations of the auxins indole-3-acetic acid, indole-3-butyric acid and alpha-naphthaleneacetic acid on the growth of micropropagated V. glechomifolia was investigated under conditions of transient and continuous exposure. Changes in the development of roots and shoots as well as the production of the valepotriates acevaltrate, valtrate and didrovaltrate (analyzed by high-performance liquid chromatography) were evaluated. The best performance in valepotriate production, growth and survival under ex vitro conditions following plant acclimatization was achieved in the continuous presence of 5.71 microM IAA. When cultured in medium containing IAA plants produced stable levels of valepotriates throughout the entire cultivation period.