OBJECTIVE: To Investigate the effects of lithocholic acid (LCA) on the balance between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: Twelve 10-week-old SPF C57BL/6J female mice were randomly divided into an experimental group (undergoing bilateral ovariectomy) and a control group (only removing the same volume of adipose tissue around the ovaries), with 6 mice in each group. The body mass was measured every week after operation. After 4 weeks post-surgery, the weight of mouse uterus was measured, femur specimens of the mice were taken for micro-CT scanning and three-dimensional reconstruction to analyze changes in bone mass. Tibia specimens were taken for HE staining to calculate the number and area of bone marrow adipocytes in the marrow cavity area. ELISA was used to detect the expression of bone turnover markers in the serum. Liver samples were subjected to real-time fluorescence quantitative PCR (RT-qPCR) to detect the expression of key genes related to bile acid metabolism, including cyp7a1, cyp7b1, cyp8b1, and cyp27a1. BMSCs were isolated by centrifugation from 2 C57BL/6J female mice (10-week-old). The third-generation cells were exposed to 0, 1, 10, and 100 μmol/L LCA, following which cell viability was evaluated using the cell counting kit 8 assay. Subsequently, alkaline phosphatase (ALP) staining and oil red O staining were conducted after 7 days of osteogenic and adipogenic induction. RT-qPCR was employed to analyze the expressions of osteogenic-related genes, namely ALP, Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), as well as adipogenic-related genes including Adiponectin (Adipoq), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ (PPARγ). RESULTS: Compared with the control group, the body mass of the mice in the experimental group increased, the uterus atrophied, the bone mass decreased, the bone marrow fat expanded, and the bone metabolism showed a high bone turnover state. RT-qPCR showed that the expressions of cyp7a1, cyp8b1, and cyp27a1, which were related to the key enzymes of bile acid metabolism in the liver, decreased significantly ( P<0.05), while the expression of cyp7b1 had no significant difference ( P>0.05). Intervention with LCA at concentrations of 1, 10, and 100 μmol/L did not demonstrate any apparent toxic effects on BMSCs. Furthermore, LCA inhibited the expressions of osteogenic-related genes (ALP, Runx2, and OCN) in a dose-dependent manner, resulting in a reduction in ALP staining positive area. Concurrently, LCA promoted the expressions of adipogenic-related genes (Adipoq, FABP4, and PPARγ), and an increase in oil red O staining positive area. CONCLUSION After menopause, the metabolism of bile acids is altered, and secondary bile acid LCA interferes with the balance of osteogenic and adipogenic differentiation of BMSCs, thereby affecting bone remodelling.
Female ; Mice ; Animals ; Core Binding Factor Alpha 1 Subunit/pharmacology* ; PPAR gamma/metabolism* ; Steroid 12-alpha-Hydroxylase/metabolism* ; Mice, Inbred C57BL ; Cell Differentiation ; Osteogenesis ; Mesenchymal Stem Cells ; Bile Acids and Salts/pharmacology* ; Bone Marrow Cells ; Cells, Cultured ; Azo Compounds

OBJECTIVE: To explore the effect of chitosan (CS) hydrogel loaded with tendon-derived stem cells (TDSCs; hereinafter referred to as TDSCs/CS hydrogel) on tendon-to-bone healing after rotator cuff repair in rabbits. METHODS: TDSCs were isolated from the rotator cuff tissue of 3 adult New Zealand white rabbits by Henderson step-by-step enzymatic digestion method and identified by multidirectional differentiation and flow cytometry. The 3rd generation TDSCs were encapsulated in CS to construct TDSCs/CS hydrogel. The cell counting kit 8 (CCK-8) assay was used to detect the proliferation of TDSCs in the hydrogel after 1-5 days of culture in vitro, and cell compatibility of TDSCs/CS hydrogel was evaluated by using TDSCs alone as control. Another 36 adult New Zealand white rabbits were randomly divided into 3 groups ( n=12): rotator cuff repair group (control group), rotator cuff repair+CS hydrogel injection group (CS group), and rotator cuff repair+TDSCs/CS hydrogel injection group (TDSCs/CS group). After establishing the rotator cuff repair models, the corresponding hydrogel was injected into the tendon-to-bone interface in the CS group and TDSCs/CS group, and no other treatment was performed in the control group. The general condition of the animals was observed after operation. At 4 and 8 weeks, real-time quantitative PCR (qPCR) was used to detect the relative expressions of tendon forming related genes (tenomodulin, scleraxis), chondrogenesis related genes (aggrecan, sex determining region Y-related high mobility group-box gene 9), and osteogenesis related genes (alkaline phosphatase, Runt-related transcription factor 2) at the tendon-to-bone interface. At 8 weeks, HE and Masson staining were used to observe the histological changes, and the biomechanical test was used to evaluate the ultimate load and the failure site of the repaired rotator cuff to evaluate the tendon-to-bone healing and biomechanical properties. RESULTS: CCK-8 assay showed that the CS hydrogel could promote the proliferation of TDSCs ( P<0.05). qPCR results showed that the expressions of tendon-to-bone interface related genes were significantly higher in the TDSCs/CS group than in the CS group and control group at 4 and 8 weeks after operation ( P<0.05). Moreover, the expressions of tendon-to-bone interface related genes at 8 weeks after operation were significantly higher than those at 4 weeks after operation in the TDSCs/CS group ( P<0.05). Histological staining showed the clear cartilage tissue and dense and orderly collagen formation at the tendon-to-bone interface in the TDSCs/CS group. The results of semi-quantitative analysis showed that compared with the control group, the number of cells, the proportion of collagen fiber orientation, and the histological score in the TDSCs/CS group increased, the vascularity decreased, showing significant differences ( P<0.05); compared with the CS group, the proportion of collagen fiber orientation and the histological score in the TDSCs/CS group significantly increased ( P<0.05), while there was no significant difference in the number of cells and vascularity ( P>0.05). All samples in biomechanical testing failed at the repair site during the testing process. The ultimate load of the TDSCs/CS group was significantly higher than that of the control group ( P<0.05), but there was no significant difference compared to the CS group ( P>0.05). CONCLUSION TDSCs/CS hydrogel can induce cartilage regeneration to promote rotator cuff tendon-to-bone healing.
Rabbits ; Animals ; Rotator Cuff/surgery* ; Chitosan ; Hydrogels ; Rotator Cuff Injuries/surgery* ; Wound Healing ; Tendons/surgery* ; Collagen ; Stem Cells ; Biomechanical Phenomena

OBJECTIVE: To summarize the progress of the roles and mechanisms of various types of stem cell-based treatments and their combination therapies in both animal studies and clinical trials of lymphedema. METHODS: The literature on stem cell-based treatments for lymphedema in recent years at home and abroad was extensively reviewed, and the animal studies and clinical trials on different types of stem cells for lymphedema were summarized. RESULTS: Various types of stem cells have shown certain effects in animal studies and clinical trials on the treatment of lymphedema, mainly through local differentiation into lymphoid endothelial cells and paracrine cytokines with different functions. Current research focuses on two cell types, adipose derived stem cells and bone marrow mesenchymal stem cells, both of which have their own advantages and disadvantages, mainly reflected in the therapeutic effect of stem cells, the difficulty of obtaining stem cells and the content in vivo. In addition, stem cells can also play a synergistic role in combination with other treatments, such as conservative treatment, surgical intervention, cytokines, biological scaffolds, and so on. However, it is still limited to the basic research stage, and only a small number of studies have completed clinical trials. CONCLUSION Stem cells have great transformation potential in the treatment of lymphedema, but there is no unified standard in the selection of cell types, the amount of transplanted cells, and the timing of transplantation.
Animals ; Endothelial Cells ; Lymphedema/therapy* ; Stem Cell Transplantation ; Cytokines

Hearing loss has become increasingly prevalent and causes considerable disability, thus gravely burdening the global economy. Irreversible loss of hair cells is a main cause of sensorineural hearing loss, and currently, the only relatively effective clinical treatments are limited to digital hearing equipment like cochlear implants and hearing aids, but these are of limited benefit in patients. It is therefore urgent to understand the mechanisms of damage repair in order to develop new neuroprotective strategies. At present, how to promote the regeneration of functional hair cells is a key scientific question in the field of hearing research. Multiple signaling pathways and transcriptional factors trigger the activation of hair cell progenitors and ensure the maturation of newborn hair cells, and in this article, we first review the principal mechanisms underlying hair cell reproduction. We then further discuss therapeutic strategies involving the co-regulation of multiple signaling pathways in order to induce effective functional hair cell regeneration after degeneration, and we summarize current achievements in hair cell regeneration. Lastly, we discuss potential future approaches, such as small molecule drugs and gene therapy, which might be applied for regenerating functional hair cells in the clinic.
Infant, Newborn ; Humans ; Hair Cells, Auditory, Inner/physiology* ; Ear, Inner/physiology* ; Hair Cells, Auditory/physiology* ; Regeneration/genetics* ; Stem Cells

Cell Competition ; Neural Stem Cells ; Cell Differentiation

The scientific basis of acupuncture on mesenchymal stem cells (MSCs) for treating ischemic stroke (IS) is discussed. MSCs transplantation has great potential for the treatment of tissue damage caused by early stage inflammatory cascade reactions of IS, but its actual transformation is limited by various factors. How to improve the homing efficiency of MSCs is the primary issue to enhance its efficacy. As such, the possible mechanisms of acupuncture and MSCs transplantation in inhibiting inflammatory cascade reactions induced by IS are explored by reviewing literature, and a hypothesis that acupuncture could promote the secretion of stromal cell-derived factor-1α (SDF-1α) from ischemic foci to regulate SDF-1α/CXC chemokine receptor 4 (CXCR4) axis, thereby improving the homing efficiency of MSCs transplantation, exerting its neuroprotective function, and improving the bed transformation ability, is proposed.
Humans ; Ischemic Stroke ; Chemokine CXCL12 ; Acupuncture Therapy ; Mesenchymal Stem Cells ; Inflammation

BACKGROUND: Hair follicles are easily accessible and contain stem cells with different developmental origins, including mesenchymal stem cells (MSCs), that consequently reveal the potential of human hair follicle (hHF)-derived MSCs in repair and regeneration. However, the role of hHF-MSCs in Achilles tendinopathy (AT) remains unclear. The present study investigated the effects of hHF-MSCs on Achilles tendon repair in rabbits. METHODS: First, we extracted and characterized hHF-MSCs. Then, a rabbit tendinopathy model was constructed to analyze the ability of hHF-MSCs to promote repair in vivo . Anatomical observation and pathological and biomechanical analyses were performed to determine the effect of hHF-MSCs on AT, and quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical staining were performed to explore the molecular mechanisms through which hHF-MSCs affects AT. Furthermore, statistical analyses were performed using independent sample t test, one-way analysis of variance (ANOVA), and one-way repeated measures multivariate ANOVA as appropriate. RESULTS: Flow cytometry, a trilineage-induced differentiation test, confirmed that hHF-derived stem cells were derived from MSCs. The effect of hHF-MSCs on AT revealed that the Achilles tendon was anatomically healthy, as well as the maximum load carried by the Achilles tendon and hydroxyproline proteomic levels were increased. Moreover, collagen I and III were upregulated in rabbit AT treated with hHF-MSCs (compared with AT group; P  < 0.05). Analysis of the molecular mechanisms revealed that hHF-MSCs promoted collagen fiber regeneration, possibly through Tenascin-C (TNC) upregulation and matrix metalloproteinase (MMP)-9 downregulation. CONCLUSIONS hHF-MSCs can be a treatment modality to promote AT repair in rabbits by upregulating collagen I and III. Further analysis revealed that treatment of AT using hHF-MSCs promoted the regeneration of collagen fiber, possibly because of upregulation of TNC and downregulation of MMP-9, thus suggesting that hHF-MSCs are more promising for AT.
Animals ; Humans ; Rabbits ; Hair Follicle ; Achilles Tendon/pathology* ; Tendinopathy/pathology* ; Proteomics ; Collagen Type I ; Mesenchymal Stem Cells

Vascular wall-resident stem cells (VW-SCs) play a critical role in maintaining normal vascular function and regulating vascular repair. Understanding the basic functional characteristics of the VW-SCs will facilitate the study of their regulation and potential therapeutic applications. The aim of this study was to establish a stable method for the isolation, culture, and validation of the CD34⁺ VW-SCs from mice, and to provide abundant and reliable cell sources for further study of the mechanisms involved in proliferation, migration and differentiation of the VW-SCs under various physiological and pathological conditions. The vascular wall cells of mouse aortic adventitia and mesenteric artery were obtained by the method of tissue block attachment and purified by magnetic microbead sorting and flow cytometry to obtain the CD34⁺ VW-SCs. Cell immunofluorescence staining was performed to detect the stem cell markers (CD34, Flk-1, c-kit, Sca-1), smooth muscle markers (SM22, SM MHC), endothelial marker (CD31), and intranuclear division proliferation-related protein (Ki-67). To verify the multipotency of the isolated CD34⁺ VW-SCs, endothelial differentiation medium EBM-2 and fibroblast differentiation medium FM-2 were used. After culture for 7 days and 3 days respectively, endothelial cell markers and fibroblast markers of the differentiated cells were evaluated by immunofluorescence staining and q-PCR. Furthermore, the intracellular Ca²⁺ release and extracellular Ca²⁺ entry signaling were evaluated by TILLvisION system in Fura-2/AM loaded cells. The results showed that: (1) High purity (more than 90%) CD34⁺ VW-SCs from aortic adventitia and mesenteric artery of mice were harvested by means of tissue block attachment method and magnetic microbead sorting; (2) CD34⁺ VW-SCs were able to differentiate into endothelial cells and fibroblasts in vitro; (3) Caffeine and ATP significantly activated intracellular Ca²⁺ release from endoplasmic reticulum of CD34⁺ VW-SCs. Store-operated Ca²⁺ entry (SOCE) was activated by using thapsigargin (TG) applied in Ca²⁺-free/Ca²⁺ reintroduction protocol. This study successfully established a stable and efficient method for isolation, culture and validation of the CD34⁺ VW-SCs from mice, which provides an ideal VW-SCs sources for the further study of cardiovascular diseases.
Mice ; Animals ; Endothelial Cells ; Cell Differentiation/physiology* ; Stem Cells ; Adventitia ; Fibroblasts ; Cells, Cultured ; Antigens, CD34/metabolism*

OBJECTIVES: This study aimed to investigate how naringenin (Nar) affected the anti-inflammatory, vascula-rization, and osteogenesis differentiation of human periodontal ligament stem cells (hPDLSCs) stimulated by lipopolysaccharide (LPS) and to preliminarily explore the underlying mechanism. METHODS: Cell-counting kit-8 (CCK8), cell scratch test, and Transwell assay were used to investigate the proliferation and migratory capabilities of hPDLSCs. Alkaline phosphatase (ALP) staining, alizarin red staining, lumen-formation assay, enzyme-linked immunosorbent assay, quantitative timed polymerase chain reaction, and Western blot were used to measure the expression of osteopontin (OPN), Runt-related transcription factor 2 (RUNX2), vascular endothlial growth factor (VEGF), basic fibroblast growth factor (bFGF), von Willebrand factor (vWF), tumor necrosis factor-α (TNF-α), and interleukin (IL)-6. RESULTS: We observed that 10 μmol/L Nar could attenuate the inflammatory response of hPDLSCs stimulated by 10 μg/mL LPS and promoted their proliferation, migration, and vascularization differentiation. Furthermore, 0.1 μmol/L Nar could effectively restore the osteogenic differentiation of inflammatory hPDLSCs. The effects of Nar's anti-inflammatory and promotion of osteogenic differentiation significantly decreased and inflammatory vascularization differentiation increased after adding AMD3100 (a specific CXCR4 inhibitor). CONCLUSIONS Nar demonstrated the ability to promote the anti-inflammatory, vascularization, and osteogenic effects of hPDLSCs stimulated by LPS, and the ability was associated with the stromal cell-derived factor/C-X-C motif chemokine receptor 4 signaling axis.
Humans ; Anti-Inflammatory Agents/pharmacology* ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12 ; Lipopolysaccharides/pharmacology* ; Osteogenesis ; Periodontal Ligament/metabolism* ; Receptors, Chemokine/metabolism* ; Stem Cells ; Interleukin-8/metabolism*

In recent years, mesenchymal stem cell (MSCs)-derived exosomes have attracted much attention in the field of tissue regeneration. Mesenchymal stem cell-derived exosomes are signaling molecules for communication among cells. They are characterized by natural targeting and low immunogenicity, and are mostly absorbed by cells through the paracrine pathway of mesenchymal stem cells. Moreover, they participate in the regulation and promotion of cell or tissue regeneration. As a scaffold material in regenerative medicine, hydrogel has good biocompatibility and degradability. Combining the two compounds can not only improve the retention time of exosomes at the lesion site, but also improve the dose of exosomes reaching the lesion site by in situ injection, and the therapeutic effect in the lesion area is significant and continuous. This paper summarizes the research results of the interaction of exocrine and hydrogel composite materials to promote tissue repair and regeneration, in order to facilitate research in the field of tissue regeneration in the future.
Hydrogels/metabolism* ; Exosomes/metabolism* ; Wound Healing ; Regenerative Medicine ; Mesenchymal Stem Cells/metabolism*