Proteomic profiling of extracellular vesicles derived from human serum for the discovery of biomarkers in Avascular necrosis.

BACKGROUND: Avascular necrosis (AVN) is a medical condition characterized by the destruction of bone tissue due to a diminished blood supply. When the rate of tissue destruction surpasses the rate of regeneration, effective treatment becomes challenging, leading to escalating pain, arthritis, and bone fragility as the disease advances. A timely diagnosis is imperative to prevent and initiate proactive treatment for osteonecrosis. We explored the potential of differentially expressed proteins in serum-derived extracellular vesicles (EVs) as biomarkers for AVN of the femoral head in humans. We analyzed the genetic material contained in serum-derived exosomes from patients for early diagnosis, treatment, and prognosis of avascular necrosis. METHODS: EVs were isolated from the serum of both patients with AVN and a control group of healthy individuals. Proteomic analyses were conducted to compare the expression patterns of these proteins by proteomic analysis using LC-MS/MS. RESULTS: Our results show that the levels of IGHV3-23, FN1, VWF, FGB, PRG4, FCGBP, and ZSWIM9 were upregulated in the EVs of patients with AVN compared with those of healthy controls. ELISA results showed that VWF and PRG4 were significantly upregulated in the patients with AVN. CONCLUSIONS: These findings suggest that these EV proteins could serve as promising biomarkers for the early detection and diagnosis of AVN. Early diagnosis is paramount for effective treatment, and the identification of new osteonecrosis biomarkers is essential to facilitate swift diagnosis and proactive intervention. Our study provides novel insights into the identification of AVN-related biomarkers that can enhance clinical management and treatment outcomes.

Extracellular Vesicles from Human Adipose Tissue-Derived Mesenchymal Stem Cells Suppress RANKL-Induced Osteoclast Differentiation via miR122-5p.

Researchers are increasingly interested in cell therapy using mesenchymal stem cells (MSCs) as an alternative remedy for osteoporosis, with fewer side effects. Thus, we isolated and characterized extracellular vesicles (EVs) from human adipose tissue-derived MSCs (hMSCs) and investigated their inhibitory effects on RANKL-induced osteoclast differentiation. Purified EVs were collected from the supernatant of hMSCs by tangential flow filtration. Characterization of EVs included typical evaluation of the size and concentration of EVs by nanoparticle tracking analysis and morphology analysis using transmission electron microscopy. hMSC-EVs inhibited RANKL-induced differentiation of bone marrow-derived macrophages (BMDMs) into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by EV treatment of osteoclasts. In addition, EVs decreased RANKL-induced phosphorylation of p38 and JNK and expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. To elucidate which part of the hMSC-EVs plays a role in the inhibition of osteoclast differentiation, we analyzed miRNA profiles in hMSC-EVs. The results showed that has-miR122-5p was present at significantly high read counts. Overexpression of miR122-5p in BMDMs significantly inhibited RANKL-induced osteoclast differentiation and induced defects in F-actin ring formation and bone resorption. Our results also revealed that RANKL-induced phosphorylation of p38 and JNK and osteoclast-specific gene expression was decreased by miR122-5p transfection, which was consistent with the results of hMSC-EVs. These findings suggest that hMSC-EVs containing miR122-5p inhibit RANKL-induced osteoclast differentiation via the downregulation of molecular mechanisms and could be a preventive candidate for destructive bone diseases.

Comparisons of Extracellular Vesicles from Human Epidural Fat-Derived Mesenchymal Stem Cells and Fibroblast Cells.

Extracellular vesicles (EVs) are generated and secreted by cells into the circulatory system. Stem cell-derived EVs have a therapeutic effect similar to that of stem cells and are considered an alternative method for cell therapy. Accordingly, research on the characteristics of EVs is emerging. EVs were isolated from human epidural fat-derived mesenchymal stem cells (MSCs) and human fibroblast culture media by ultracentrifugation. The characterization of EVs involved the typical evaluation of cluster of differentiation (CD antigens) marker expression by fluorescence-activated cell sorting, size analysis with dynamic laser scattering, and morphology analysis with transmission electron microscopy. Lastly, the secreted levels of cytokines and chemokines in EVs were determined by a cytokine assay. The isolated EVs had a typical size of approximately 30-200 nm, and the surface proteins CD9 and CD81 were expressed on human epidural fat MSCs and human fibroblast cells. The secreted levels of cytokines and chemokines were compared between human epidural fat MSC-derived EVs and human fibroblast-derived EVs. Human epidural fat MSC-derived EVs showed anti-inflammatory effects and promoted macrophage polarization. In this study, we demonstrated for the first time that human epidural fat MSC-derived EVs exhibit inflammatory suppressive potency relative to human fibroblast-derived EVs, which may be useful for the treatment of inflammation-related diseases.

Therapeutic Potential of Mesenchymal Stem Cells (MSCs) and MSC-Derived Extracellular Vesicles for the Treatment of Spinal Cord Injury.

Spinal cord injury (SCI) is a life-threatening condition that leads to permanent disability with partial or complete loss of motor, sensory, and autonomic functions. SCI is usually caused by initial mechanical insult, followed by a cascade of several neuroinflammation and structural changes. For ameliorating the neuroinflammatory cascades, MSC has been regarded as a therapeutic agent. The animal SCI research has demonstrated that MSC can be a valuable therapeutic agent with several growth factors and cytokines that may induce anti-inflammatory and regenerative effects. However, the therapeutic efficacy of MSCs in animal SCI models is inconsistent, and the optimal method of MSCs remains debatable. Moreover, there are several limitations to developing these therapeutic agents for humans. Therefore, identifying novel agents for regenerative medicine is necessary. Extracellular vesicles are a novel source for regenerative medicine; they possess nucleic acids, functional proteins, and bioactive lipids and perform various functions, including damaged tissue repair, immune response regulation, and reduction of inflammation. MSC-derived exosomes have advantages over MSCs, including small dimensions, low immunogenicity, and no need for additional procedures for culture expansion or delivery. Certain studies have demonstrated that MSC-derived extracellular vesicles (EVs), including exosomes, exhibit outstanding chondroprotective and anti-inflammatory effects. Therefore, we reviewed the principles and patho-mechanisms and summarized the research outcomes of MSCs and MSC-derived EVs for SCI, reported to date.

Serum-Derived Neuronal Exosomal miRNAs as Biomarkers of Acute Severe Stress.

Stress is the physical and psychological tension felt by an individual while adapting to difficult situations. Stress is known to alter the expression of stress hormones and cause neuroinflammation in the brain. In this study, miRNAs in serum-derived neuronal exosomes (nEVs) were analyzed to determine whether differentially expressed miRNAs could be used as biomarkers of acute stress. Specifically, acute severe stress was induced in Sprague-Dawley rats via electric foot-shock treatment. In this acute severe-stress model, time-dependent changes in the expression levels of stress hormones and neuroinflammation-related markers were analyzed. In addition, nEVs were isolated from the serum of control mice and stressed mice at various time points to determine when brain damage was most prominent; this was found to be 7 days after foot shock. Next-generation sequencing was performed to compare neuronal exosomal miRNA at day 7 with the neuronal exosomal miRNA of the control group. From this analysis, 13 upregulated and 11 downregulated miRNAs were detected. These results show that specific miRNAs are differentially expressed in nEVs from an acute severe-stress animal model. Thus, this study provides novel insights into potential stress-related biomarkers.

Bone Marrow Aspirate Concentrate: Its Uses in Osteoarthritis.

Human bone marrow (BM) is a kind of source of mesenchymal stem cells (MSCs) as well as growth factors and cytokines that may aid anti-inflammation and regeneration for various tissues, including cartilage and bone. However, since MSCs in BM usually occupy only a small fraction (0.001%) of nucleated cells, bone marrow aspirate concentrate (BMAC) for cartilage pathologies, such as cartilage degeneration, defect, and osteoarthritis, have gained considerable recognition in the last few years due to its potential benefits including disease modifying and regenerative capacity. Although further research with well-designed, randomized, controlled clinical trials is needed to elucidate the exact mechanism of BMAC, this may have the most noteworthy effect in patients with osteoarthritis. The purpose of this article is to review the general characteristics of BMAC, including its constituent, action mechanisms, and related issues. Moreover, this article aims to summarize the clinical outcomes of BMAC reported to date.

Preserved Hippocampal Glucose Metabolism on 18F-FDG PET after Transplantation of Human Umbilical Cord Blood-derived Mesenchymal Stem Cells in Chronic Epileptic Rats.

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) may be a promising modality for treating medial temporal lobe epilepsy. (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a noninvasive method for monitoring in vivo glucose metabolism. We evaluated the efficacy of hUCB-MSCs transplantation in chronic epileptic rats using FDG-PET. Rats with recurrent seizures were randomly assigned into three groups: the stem cell treatment (SCT) group received hUCB-MSCs transplantation into the right hippocampus, the sham control (ShC) group received same procedure with saline, and the positive control (PC) group consisted of treatment-negative epileptic rats. Normal rats received hUCB-MSCs transplantation acted as the negative control (NC). FDG-PET was performed at pre-treatment baseline and 1- and 8-week posttreatment. Hippocampal volume was evaluated and histological examination was done. In the SCT group, bilateral hippocampi at 8-week after transplantation showed significantly higher glucose metabolism (0.990 ± 0.032) than the ShC (0.873 ± 0.087; P < 0.001) and PC groups (0.858 ± 0.093; P < 0.001). Histological examination resulted that the transplanted hUCB-MSCs survived in the ipsilateral hippocampus and migrated to the contralateral hippocampus but did not differentiate. In spite of successful engraftment, seizure frequency among the groups was not significantly different. Transplanted hUCB-MSCs can engraft and migrate, thereby partially restoring bilateral hippocampal glucose metabolism. The results suggest encouraging effect of hUCB-MSCs on restoring epileptic networks.

Human umbilical cord blood mesenchymal stem cells reduce colitis in mice by activating NOD2 signaling to COX2.

BACKGROUND & AIMS: Decreased levels or function of nucleotide-binding oligomerization domain 2 (NOD2) are associated with Crohn's disease. NOD2 regulates intestinal inflammation, and also is expressed by human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs), to regulate their differentiation. We investigated whether NOD2 is required for the anti-inflammatory activities of MSCs in mice with colitis. METHODS: Colitis was induced in mice by administration of dextran sulfate sodium or trinitrobenzene sulfonic acid. Mice then were given intraperitoneal injections of NOD2-activated hUCB-MSCs; colon tissues and mesenteric lymph nodes were collected for histologic analyses. A bromodeoxyuridine assay was used to determine the ability of hUCB-MSCs to inhibit proliferation of human mononuclear cells in culture. RESULTS: Administration of hUCB-MSCs reduced the severity of colitis in mice. The anti-inflammatory effects of hUCB-MSCs were greatly increased by activation of NOD2 by its ligand, muramyl dipeptide (MDP). Administration of NOD2-activated hUCB-MSCs increased anti-inflammatory responses in colons of mice, such as production of interleukin (IL)-10 and infiltration by T regulatory cells, and reduced production of inflammatory cytokines. Proliferation of mononuclear cells was inhibited significantly by co-culture with hUCB-MSCs that had been stimulated with MDP. MDP induced prolonged production of prostaglandin (PG)E2 in hUCB-MSCs via the NOD2-RIP2 pathway, which suppressed proliferation of mononuclear cells derived from hUCB. PGE2 produced by hUCB-MSCs in response to MDP increased production of IL-10 and T regulatory cells. In mice, production of PGE2 by MSCs and subsequent production of IL-10 were required to reduce the severity of colitis. CONCLUSIONS: Activation of NOD2 is required for the ability of hUCB-MSCs to reduce the severity of colitis in mice. NOD2 signaling increases the ability of these cells to suppress mononuclear cell proliferation by inducing production of PGE2.

Enhanced Dural Repair Using Biodegradable Sealants Based on Photocurable Hyaluronic Acid.

Cerebrospinal fluid (CSF) leakage is a common complication of intradural surgery or incidental durotomy in neurosurgery. Dural suturing is a common method for durotomy repair, but this technique requires a long operation time and includes the risk of CSF leakage by incomplete sealing. Glue-type sealants are effective for watertight dural closure. However, unresolved shortcomings include insufficient sealing performance, poor biocompatibility, and excessive swelling. Here, a dural sealant using light-activated hyaluronic acid (HA) with multi-networks (HA photosealant) that provides fast sealing performance and high biocompatibility is reported. The HA photosealants form a watertight hydrogel barrier with multilength networks under low-energy visible light exposure (405 nm, <1 J cm-2) for 5 s and allow firm tissue adhesion on the wet dural surface. In a rabbit model of craniectomy and durotomy, HA photosealants exhibit the faster sealing performance of dural tears and enhance dural repair with accelerated bone formation compared to commercial surgical glues, with no degenerative changes, such as inflammation or necrosis, in histopathological evaluation. This biocompatible HA photosealant can be applied in a variety of clinical settings that require fast wound closure as a promising potential.

Antioxidant and Antimelanogenic Activities of Lactobacillus kunkeei NCHBL-003 Isolated from Honeybees.

Excessive reactive oxygen species production can detrimentally impact skin cell physiology, resulting in cell growth arrest, melanogenesis, and aging. Recent clinical studies have found that lactic acid bacteria have a special effect directly or indirectly on skin organs, but the exact mechanism has not been elucidated. In this study, we investigated the mechanisms underlying the antioxidant protective effect and the inhibitory effect on melanin synthesis of Lactobacillus kunkeei culture supernatant (CSK), isolated from Apis mellifera Linnaeus (the Western honeybee). CSK exhibited notable efficacy in promoting cell migration and wound healing under oxidative stress, surpassing the performance of other strains. CSK pretreatment significantly upregulated the expression of Nrf2/HO-1 (nuclear factor erythroid 2-related factor 2/heme oxygenase-1), a key player in cellular defenses against oxidative stress, relative to the control H2O2-treated cells. The DCF-DA (dichloro-dihydro-fluorescein diacetate) assay results confirmed that CSK's ability to enhance Nrf2 and HO-1 expression aligns with its robust ability to remove H2O2-induced reactive oxygen species. Furthermore, CSK upregulated MAPK (mitogen-activated protein kinase) phosphorylation, an upstream signal for HO-1 expression, and MAPK inhibitors compromised the wound-healing effect of CSK. Additionally, CSK exhibited inhibitory effects on melanin synthesis, downregulating melanogenesis-related genes in B16F10 cells. Thus, the present study demonstrated that CSK exhibited antioxidant effects by activating the Nrf2/HO-1 pathway through MAPK phosphorylation, thereby restoring cell migration and demonstrating inhibitory effects on melanin production. These findings emphasize the antioxidant and antimelanogenic potential of CSK, suggesting its potential use as a therapeutic agent, promoting wound healing, and as an active ingredient in skin-lightening cosmetics.

Red ginseng extract inhibits lipopolysaccharide-induced platelet-leukocyte aggregates in mice.

Background: Platelet-leukocyte aggregates (PLAs) play important roles in cardiovascular disease and sepsis. Red ginseng extract (RGE) has been well-studied for its antiplatelet and anti-inflammatory activities. However, the potential inhibitory effects of RGE on PLA have not been investigated. Methods: Six-week-old ICR mice were given oral gavage of RGE for 7 days, followed by an intraperitoneal injection of 15 mg/kg of lipopolysaccharide. Mice were euthanized 24 h later, and blood samples were collected for further analysis. Flow cytometry was utilized to sort populations of PLAs and platelet-neutrophil aggregates (PNAs). By using confocal microscopy, PNAs were validated. Morphological changes in platelets and leukocytes were visualized with scanning electron microscopy. Expressions of tissue factor (TF) and platelet factor 4 (PF4) were investigated using enzyme-linked immunosorbent assay. Results: Populations of activated platelets, PLAs and PNAs, were significantly increased with LPS-induction. Treatment with 200 and 400 mg/kg of RGE decreased platelet activation. Moreover, the populations of PLAs and PNAs were reduced. PNAs were visible in the blood of septic mice, and this was attenuated by treatment with 400 mg/kg of RGE. Morphologically, sepsisinduced platelet activation and fibrin formation in the blood. This was reduced with RGE treatment. Sepsis-induced increase in the plasma levels of TF and PF4 was also reduced with RGE treatment. Conclusion: This study shows that RGE is a potential therapeutic that reduces the activation of platelets and targets PLA and PNA formation. Detailed inhibitory mechanisms of RGE should be studied.

Therapeutic potential of small extracellular vesicles derived from mesenchymal stem cells for spinal cord and nerve injury.

Neural diseases such as compressive, congenital, and traumatic injuries have diverse consequences, from benign mild sequelae to severe life-threatening conditions with associated losses of motor, sensory, and autonomic functions. Several approaches have been adopted to control neuroinflammatory cascades. Traditionally, mesenchymal stem cells (MSCs) have been regarded as therapeutic agents, as they possess growth factors and cytokines with potential anti-inflammatory and regenerative effects. However, several animal model studies have reported conflicting outcomes, and therefore, the role of MSCs as a regenerative source for the treatment of neural pathologies remains debatable. In addition, issues such as heterogeneity and ethical issues limited their use as therapeutic agents. To overcome the obstacles associated with the use of traditional agents, we explored the therapeutic potentials of extracellular vesicles (EVs), which contain nucleic acids, functional proteins, and bioactive lipids, and play crucial roles in immune response regulation, inflammation reduction, and cell-to-cell communication. EVs may surpass MSCs in size issue, immunogenicity, and response to the host environment. However, a comprehensive review is required on the therapeutic potential of EVs for the treatment of neural pathologies. In this review, we discuss the action mechanism of EVs, their potential for treating neural pathologies, and future perspectives regarding their clinical applications.

The anti-platelet activity of panaxadiol fraction and panaxatriol fraction of Korean Red Ginseng in vitro and ex vivo.

Background: The anti-platelet activity of the saponin fraction of Korean Red Ginseng has been widely studied. The saponin fraction consists of the panaxadiol fraction (PDF) and panaxatriol fraction (PTF); however, their anti-platelet activity is yet to be compared. Our study aimed to investigate the potency of anti-platelet activity of PDF and PTF and to elucidate how well they retain their anti-platelet activity via different administration routes. Methods: For ex vivo studies, Sprague-Dawley rats were orally administered 250 mg/kg PDF and PTF for 7 consecutive days before blood collection via cardiac puncture. Platelet aggregation was conducted after isolation of the washed platelets. For in vitro studies, washed platelets were obtained from Sprague-Dawley rats. Collagen and adenosine diphosphate (ADP) were used to induce platelet aggregation. Collagen was used as an agonist for assaying adenosine triphosphate release, thromboxane B2, serotonin, cyclic adenosine monophosphate, and cyclic guanosine monophosphate (cGMP) release. Results: When treated ex vivo, PDF not only inhibited ADP and collagen-induced platelet aggregation, but also upregulated cGMP levels and reduced platelet adhesion to fibronectin. Furthermore, it also inhibited Akt phosphorylation induced by collagen treatment. Panaxadiol fraction did not exert any anti-platelet activity in vitro, whereas PTF exhibited potent anti-platelet activity, inhibiting ADP, collagen, and thrombin-induced platelet aggregation, but significantly elevated levels of cGMP. Conclusion: Our study showed that in vitro and ex vivo PDF and PTF treatments exhibited different potency levels, indicating possible metabolic conversions of ginsenosides, which altered the content of ginsenosides capable of preventing platelet aggregation.

Therapeutic effects of human amniotic epithelial stem cells in Niemann-Pick type C1 mice.

BACKGROUND AIMS: Niemann-Pick disease type C1 (NPC) is an autosomal recessive cholesterol-storage disorder characterized by liver dysfunction, hepatosplenomegaly and progressive neurodegeneration. Thus far, studies of NPC mice have been performed mainly to study the brain and neurodegeneration, because degeneration in the brain was known as the primary cause of death in NPC mice. However, NPC is a systemic disease; therefore the purpose of this study was to find the possibility of a general therapeutic effect by applying and tracking transplanted human amniotic epithelial stem cells (hAESC) in NPC mice. METHODS: hAESC were administered to NPC homozygous (NPC(-/-)) mice via intravenous injection from 5 weeks of age; each recipient received 5 × 10(5) cells every other week. The body weight of each of the mice was measured every week, and the survival and state of each mouse was evaluated every day. The weight of the organs was measured, and serum chemistry, histology and the intensity of Filipin staining were evaluated. RESULTS: The effect of cell transplantation was to extend the life span and reduce the rapid loss of weight. Moreover, alleviation of tissue damage was observed more in hAESC-treated NPC(-/-) mice than in non-treated NPC(-/-) mice. Cholesterol deposition was reduced after transplantation, and the relative weight of the liver was also decreased. CONCLUSIONS: These data show that hAESC could delay the degeneration caused by fatal genetic disorders such as NPC. This study presents the prospect of relief of precipitous disease progression and the therapeutic possibility of applying hAESC to fatal genetic disorders.

The simplest method for in vitro ß-cell production from human adult stem cells.

Diabetes mellitus is a challenging autoimmune disease. Biomedical researchers are currently exploring efficient and effective ways to solve this challenge. The potential of stem cell therapies for treating diabetes represents one of the major focuses of current research on diabetes treatment. Here, we have attempted to differentiate adult stem cells from umbilical cord blood-derived mesenchymal cells (UCB-MSC), Wharton's jelly-derived mesenchymal stem cells (WJ-MSC) and amniotic epithelial stem cells (AE-SC) into insulin-producing cells. The serum-free protocol developed in this study resulted in the differentiation of cells into definitive endoderm, pancreatic foregut, pancreatic endoderm and, finally, pancreatic endocrine cells, which expressed the marker genes SOX17, PDX1, NGN3, NKX6.1, INS, GCG, and PPY, respectively. Detection of the expression of the gap junction-related gene connexin-36 (CX36) using RT-PCR provided conclusive evidence for insulin-producing cell differentiation. In addition to this RT-PCR result, insulin and C-peptide protein were detected by immunohistochemistry and ELISA. Glucose stimulation test results showed that significantly greater amounts of C-peptide and insulin were released from differentiated cells than from undifferentiated cells. In conclusion, the methods investigated in this study can be considered an effective and efficient means of obtaining insulin-producing cells from adult stem cells within a week.

In Vivo Toxicity and Pharmacokinetics of Polytetrafluoroethylene Microplastics in ICR Mice.

The increased use of plastics has led to severe environmental pollution, particularly by microplastics-plastic particles 5 mm or less in diameter. These particles are formed by environmental factors such as weathering and ultraviolet irradiation, thereby making environmental pollution worse. This environmental pollution intensifies human exposure to microplastics via food chains. Despite potential negative effects, few toxicity assessments on microplastics are available. In this study, two sizes of polytetrafluoroethylene (PTFE) microplastics, approximately 5 µm and 10-50 µm, were manufactured and used for single and four-week repeated toxicity and pharmacokinetic studies. Toxicological effects were comprehensively evaluated with clinical signs, body weight, food and water consumption, necropsy findings, and histopathological and clinical-pathological examinations. Blood collected at 15, 30 60, and 120 min after a single administration of microplastics were analyzed by Raman spectroscopy. In the toxicity evaluation of single and four-week repeated oral administration of PTFE microplastics, no toxic changes were observed. Therefore, the lethal dose 50 (LD50) and no-observed-adverse-effect-level (NOAEL) of PTFE microplastics in ICR mice were established as 2000 mg/kg or more. PTFE microplastics were not detected in blood, so pharmacokinetic parameters could not be calculated. This study provides new insight into the long-term toxicity and pharmacokinetics of PTFE microplastics.

Injectable Self-Crosslinkable Thiolated Hyaluronic Acid for Stem Cell Therapy of Atopic Dermatitis.

Stem cell therapies offer great promise in regenerative medicine to reinstate the normal function of diseased tissue, thereby avoiding the need for replacement. In stem cell therapies, damaged cells are replaced or restored by regulating inflammation and the immune system. However, the low survival rate and local retention of transplanted cells pose a significant challenge. In this study, injectable self-crosslinkable hydrogels using thiol-functionalized hyaluronic acid (HA-SH) were developed to improve the efficacy of mesenchymal stem cells (MSCs) for treating atopic dermatitis (AD)-related inflammatory lesions. The gelation kinetics and mechanical properties of HA-SH hydrogels were easily tuned by varying the concentration of the polymer in the precursor solution before injection. The MSC-laden HA-SH hydrogels exhibited high cell viability (>80%) for 1 week and good in vivo biocompatibility after implantation beneath the mouse skin. Moreover, the MSC-laden HA-SH hydrogel showed increased expression of anti-inflammatory cytokines, which can alleviate the immune response. In an AD animal model, a reduction in epidermal thickness and mast cell infiltration was achieved by applying a self-crosslinkable HA-SH solution including MSCs. This HA-based injectable hydrogel represents a potential carrier of stem cells, and its strong immunomodulation capabilities can be utilized for treating inflammation-related diseases.

Toxicity Study and Quantitative Evaluation of Polyethylene Microplastics in ICR Mice.

The production, use, and waste of plastics increased worldwide, which resulted in environmental pollution and a growing public health problem. In particular, microplastics have the potential to accumulate in humans and mammals through the food chain. However, the toxicity of microplastics is not well understood. In this study, we investigated the toxicity of 10-50 µm polyethylene microplastics following single- and 28-day repeated oral administration (three different doses of microplastics of 500, 1000, and 2000 mg/kg/day) in ICR mice. For the investigation, we administered the microplastics orally for single- and 28-day repeated. Then, the histological and clinical pathology evaluations of the rodents were performed to evaluation of the toxicity test, and Raman spectroscopy was used to directly confirm the presence of polyethylene microplastics. In the single oral dose toxicity experiments, there were no changes in body weight and necropsy of the microplastics-treated group compared with that of controls. However, a histopathological evaluation revealed that inflammation from foreign bodies was evident in the lung tissue from the 28-day repeated oral dose toxicity group. Moreover, polyethylene microplastics were detected in the lung, stomach, duodenum, ileum, and serum by Raman spectroscopy. Our results corroborated the findings of lung inflammation after repeated oral administration of polyethylene microplastics. This study provides evidence of microplastic-induced toxicity following repeated exposure to mice.

Human Epidural AD-MSC Exosomes Improve Function Recovery after Spinal Cord Injury in Rats.

Spinal cord injury (SCI) interferes with the normal function of the autonomic nervous system by blocking circuits between the sensory and motor nerves. Although many studies focus on functional recovery after neurological injury, effective neuroregeneration is still being explored. Recently, extracellular vesicles such as exosomes have emerged as cell-free therapeutic agents owing to their ability of cell-to-cell communication. In particular, exosomes released from mesenchymal stem cells (MSCs) have the potential for tissue regeneration and exhibit therapeutic effectiveness in neurological disorders. In this study, we isolated exosomes from human epidural adipose tissue-derived MSCs (hEpi AD-MSCs) using the tangential flow filtration method. The isolated exosomes were analyzed for size, concentration, shape, and major surface markers using nanoparticle tracking analysis, transmission electron microscopy, and flow cytometry. To evaluate their effect on SCI recovery, hEpi AD-MSC exosomes were injected intravenously in SCI-induced rats. hEpi AD-MSC exosomes improved the locomotor function of SCI-induced rats. The results of histopathological and cytokine assays showed that hEpi AD-MSC exosomes regulated inflammatory response. Genetic profiling of the rat spinal cord tissues revealed changes in the expression of inflammation-related genes after exosome administration. Collectively, hEpi AD-MSC exosomes are effective in restoring spinal functions by reducing the inflammatory response.

Isolation and Characterization of Extracellular Vesicle from Mesenchymal Stem Cells of the Epidural Fat of the Spine.

STUDY DESIGN: An experimental study with extracellular vesicles (EVs) from mesenchymal stem cell (MSC) of the epidural fat (EF) of the spine. PURPOSE: This study aims to isolate the exosomes from epidural fat-derived mesenchymal stem cells (EF-MSCs) and fully characterize the EF-MSC-EVs. OVERVIEW OF LITERATURE: EF-MSCs were reported in 2019, and a few studies have shown the positive outcomes of using EF-MSCs to treat specific spine pathologies. However, MSCs have significant limitations for conducting basic studies or developing therapeutic agents. Although EVs are an emerging research topic, no studies have focused on EVs, especially exosomes, from EF and EF-MSCs. METHODS: In this study, we isolated the exosomes using the tangential flow filtration (TFF) system with exosome-depleted fetal bovine serum and performed the characterization tests via western blotting, reverse transcription-polymerase chain reaction, nanoparticle tracking analysis (NTA), and transmission electron microscopy. RESULTS: In transmission electron microscopy, the exosome had a diameter of approximately 100-200 nm and had a spherical shape, whereas in the NTA, the exosome had an average diameter of 142.8 nm with a concentration of 1.27×1010 particles/mL. The flow cytometry analysis showed the expression of CD63 and CD81. The western blotting analysis showed the positive markers. CONCLUSIONS: These findings showed that isolating the exosomes via TFF resulted in high-quality EF-MSC exosome yield. Further studies with exosomes from EF-MSC are needed to evaluate the function and role of the EF tissue.