Células tronco e endodontia regenerativa / Stem cells and regenerative endodontics

Desde o incremento das pesquisas das células-tronco em 1961, por cientistas canadenses, os avanços em estudos, pesquisas e o desenvolvimento de novos tratamentos com esse tipo de recurso se mostram promissores. O uso de células-tronco é uma grande aposta tanto para a medicina quanto para a odontologia regenerativa. Os tratamentos com essa terapia podem oferecer mais qualidade de vida para as pessoas. O potencial dessas células tão especiais se encontra em duas características peculiares: elas são capazes de se multiplicarem e de se diferenciarem em outros tipos de células, como de tecidos, cartilagens e neurônios. É dessa maneira que elas têm um papel fundamental para estudos e tratamentos relacionados à regeneração. O uso de células-tronco na Odontologia torna possível diferentes processos odontológicos que oferecem mais qualidade de vida ao paciente. Isso porque fatores como defeitos genéticos, hábitos nocivos, cáries dentárias e perdas precoces dos dentes contribuem com a perda de dentes ao longo da vida. No início do século XXI, por volta dos anos de 2005, 2006, pesquisadores começaram a publicar em revistas internacionais da área uma nova técnica baseada no uso de célulastronco existentes no osso de sustentação dos dentes e na articulação dento alveolar. Esta técnica, chamada de Revascularização, promove o aparecimento de um novo tecido pulpar sadio, devolvendo ao dente sua vitalidade e higidez(AU)

Since the increase in stem cell research in 1961 by Canadian scientists, advances in studies, research and the development of new treatments with this type of resource have shown promise. The use of stem cells is a big bet for both medicine and regenerative dentistry. Treatments with this therapy can offer more quality of life for people. The potential of these very special cells lies in two peculiar characteristics: they are able to multiply and differentiate into other types of cells, such as tissues, cartilage and neurons. It is in this way that they play a key role for studies and treatments related to regeneration. The use of stem cells in dentistry makes possible different dental processes that offer more quality of life to the patient. That's because factors such as genetic defects, harmful habits, tooth decay, and early tooth loss all contribute to lifelong tooth loss. At the beginning of the twenty-first century, around the years 2005, 2006, researchers began to publish in international journals of the area a new technique based on the use of existing stem cells in the supporting bone of the teeth and in the alveolar tooth joint. This technique, called Revascularization, promotes the appearance of a new healthy pulp tissue, returning to the tooth its vitality and hygiene(AU)

Criopreservação de células-tronco mesenquimais do tecido adiposo: Uma alternativa para lipoenxertia seriada na reconstrução mamária / Cryopreservation of adipose tissue-derived mesenchymal stem cells: An alternative to serial fat grafting in breast reconstruction

Introdução: A lipoenxertia é um enxerto autólogo de células do tecido celular subcutâneo, que pode ser utilizada como técnica complementar na reconstrução mamária. Diante disso, a criopreservação de células-tronco mesenquimais provenientes de tecido adiposo (CTDAs) poderia ser uma maneira de realizar a coleta em um tempo cirúrgico e após realizar a lipoenxertia de forma fracionada. O dimetilsulfóxido (DMSO) é um criopreservante utilizado em pesquisas com células, porém é potencialmente tóxico, o que impossibilitaria a utilização de CTDAs criopreservadas na prática clínica. Novos criopreservantes celulares, sem toxicidade, vêm sendo descritos na literatura científica experimental, como as substâncias L-prolina e trealose. Com isso, esse trabalho teve como objetivo avaliar a viabilidade de CTDAs criopreservadas com a combinação de L-prolina e trealose, em um período de até 90 dias. Método: Estudo experimental, no qual foram obtidas amostras de lipoaspirado provenientes de 9 pacientes. A fração celular foi processada e congelada com L-prolina (1,5M) + trealose (0,2M), ou com DMSO + soro fetal bovino (SFB), como controle. Após 30 e 90 dias, as amostras foram descongeladas e a viabilidade celular foi avaliada pela técnica de MTT. Resultados: A análise das CTDAs, após 1 e 3 meses de congelamento, indicou que as amostras tratadas com L-prolina + trealose apresentaram viabilidade semelhante àquelas preservadas com DMSO e SFB (p=0,444). Conclusão: A associação de L-prolina e trealose manteve CTDA viáveis por 30 e 90 dias de congelamento, podendo ser uma alternativa como criopreservante celular sem toxicidade e viabilizando o uso de lipoenxertia seriada.

Introduction: Fat grafting is an autologous graft of cells from subcutaneous tissue, which can be used as a complementary technique in breast reconstruction. Given this, the cryopreservation of adipose tissue-derived mesenchymal stem cells (ADMSCs) could be a way to collect them in one surgical procedure and after performing fractional fat grafting. Dimethyl sulfoxide (DMSO) is a cryopreservative used in cell research, but it is potentially toxic, which would make it impossible to use cryopreserved ADMSCs in clinical practice. New cellular cryopreservatives, without toxicity, have been described in the experimental scientific literature, such as the substances L-proline and trehalose. Therefore, this work aimed to evaluate the viability of ADMSCs cryopreserved with the combination of L-proline and trehalose over up to 90 days. Method: Experimental study in which lipoaspirate samples were obtained from 9 patients. The cellular fraction was processed and frozen with L-proline (1.5M) + trehalose (0.2M) or with DMSO + fetal bovine serum (FBS) as control. After 30 and 90 days, the samples were thawed, and cell viability was assessed using the MTT technique. Results: The analysis of ADMSCs, after 1 and 3 months of freezing, indicated that samples treated with L-proline + trehalose showed similar viability to those preserved with DMSO and SFB (p=0.444). Conclusion: The association of L-proline and trehalose kept ADMSC viable for 30 and 90 days of freezing, and could be an alternative as a cellular cryopreservative without toxicity and enabling the use of serial fat grafting.

Stimulation of mouse hematopoietic stem cells by angiogenin and DNA preparations

Immature hematopoietic progenitors are a constant source for renewal of hemocyte populations and the basic component of the tissue and cell repair apparatus. A unique property of these cells of internalizing extracellular double-stranded DNA has been previously shown. The leukostimulatory effect demonstrated in our pioneering studies was considered to be due to the feature of this cell. In the present research, we have analyzed the effects of DNA genome reconstructor preparation (DNAgr), DNAmix, and human recombinant angiogenin on both hematopoietic stem cells and multipotent progenitors. Treatment with bone marrow cells of experimental mice with these preparations stimulates colony formation by hematopoietic stem cells and proliferation of multipotent descendants. The main lineage responsible for this is the granulocyte-macrophage hematopoietic lineage. Using fluorescent microscopy as well as FACS assay, co-localization of primitive c-Kit- and Sca-1-positive progenitors and the TAMRA-labeled double-stranded DNA has been shown. Human recombinant angiogenin was used as a reference agent. Cells with specific markers were quantified in intact bone marrow and colonies grown in the presence of inducers. Quantitative analysis revealed that a total of 14,000 fragment copies of 500 bp, which is 0.2% of the haploid genome, can be delivered into early progenitors. Extracellular double-stranded DNA fragments stimulated the colony formation in early hematopoietic progenitors from the bone marrow, which assumed their effect on cells in G0. The observed number of Sca1+/c-Kit+ cells in colonies testifies to the possibility of both symmetrical and asymmetrical division of the initial hematopoietic stem cell and its progeny.

Resveratrol Alleviates Osteoporosis by Promoting Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells via SITR1/PI3K/AKT Pathway / El Resveratrol Alivia la Osteoporosis al Promover la Diferenciación Osteogénica de las Células Madre Mesenquimales de la Médula Ósea a Través de la Vía SITR1/PI3K/AKT

SUMMARY: Senile osteoporosis is mainly caused by reduced osteoblast differentiation and has become the leading cause of fractures in the elderly worldwide. Natural organics are emerging as a potential option for the prevention and treatment of osteoporosis. This study was designed to study the effect of resveratrol on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in osteoporosis mice. A mouse model of osteoporosis was established by subcutaneous injection of dexamethasone and treated with resveratrol administered by gavage. In vivo and in vitro, we used western blot to detect protein expression, and evaluated osteogenic differentiation of BMSCs by detecting the expression of osteogenic differentiation related proteins, calcium deposition, ALP activity and osteocalcin content. Resveratrol treatment significantly increased the body weight of mice, the level of serum Ca2+, 25(OH)D and osteocalcin, ration of bone weight, bone volume/total volume, trabecular thickness, trabecular number, trabecular spacing and cortical thickness in osteoporosis mice. In BMSCs of osteoporosis mice, resveratrol treatment significantly increased the expression of Runx2, osterix (OSX) and osteocalcin (OCN) protein, the level of calcium deposition, ALP activity and osteocalcin content. In addition, resveratrol treatment also significantly increased the expression of SIRT1, p-PI3K / PI3K and p-AKT / AKT in BMSCs of osteoporosis mice. In vitro, resveratrol increased the expression of SIRT1, p-PI3K / PI3K and p-AKT / AKT, Runx2, OSX and OCN protein, the level of calcium deposition, ALP activity and osteocalcin content in BMSCs in a concentration-dependent manner, while SIRT1 knockdown significantly reversed the effect of resveratrol. Resveratrol can attenuate osteoporosis by promoting osteogenic differentiation of bone marrow mesenchymal stem cells, and the mechanism may be related to the regulation of SIRT1/PI3K/AKT pathway.

La osteoporosis senil es causada principalmente por una diferenciación reducida de osteoblastos y se ha convertido en la principal causa de fracturas en las personas mayores en todo el mundo. Los productos orgánicos naturales están surgiendo como una opción potencial para la prevención y el tratamiento de la osteoporosis. Este estudio fue diseñado para estudiar el efecto del resveratrol en la diferenciación osteogénica de las células madre mesenquimales de la médula ósea (BMSC) en ratones con osteoporosis. Se estableció un modelo de osteoporosis en ratones mediante inyección subcutánea de dexametasona y se trató con resveratrol administrado por sonda. In vivo e in vitro, utilizamos Western blot para detectar la expresión de proteínas y evaluamos la diferenciación osteogénica de BMSC detectando la expresión de proteínas relacionadas con la diferenciación osteogénica, la deposición de calcio, la actividad de ALP y el contenido de osteocalcina. El tratamiento con resveratrol aumentó significativamente el peso corporal de los ratones, el nivel sérico de Ca2+, 25(OH)D y osteocalcina, la proporción de peso óseo, el volumen óseo/ volumen total, el espesor trabecular, el número trabecular, el espaciado trabecular y el espesor cortical en ratones con osteoporosis. En BMSC de ratones con osteoporosis, el tratamiento con resveratrol aumentó significativamente la expresión de las proteínas Runx2, osterix (OSX) y osteocalcina (OCN), el nivel de deposición de calcio, la actividad de ALP y el contenido de osteocalcina. Además, el tratamiento con resveratrol también aumentó significativamente la expresión de SIRT1, p-PI3K/PI3K y p-AKT/AKT en BMSC de ratones con osteoporosis. In vitro, el resveratrol aumentó la expresión de las proteínas SIRT1, p-PI3K/PI3K y p- AKT/AKT, Runx2, OSX y OCN, el nivel de deposición de calcio, la actividad de ALP y el contenido de osteocalcina en BMSC de manera dependiente de la concentración, mientras que La caída de SIRT1 revirtió significativamente el efecto del resveratrol. El resveratrol puede atenuar la osteoporosis al promover la diferenciación osteogénica de las células madre mesenquimales de la médula ósea, y el mecanismo puede estar relacionado con la regulación de la vía SIRT1/PI3K/AKT.

Reconstruction of rat calvarial defects utilizing an ultraviolet-cured hydrogel loaded with bone marrow mesenchymal stem cells / 口腔疾病防治

Objective@#To investigate the osteogenic properties of a methacrylated gelatin (GelMA) / bone marrow mesenchymal stem cells (BMSCs) composite hydrogel applied to the skull defect area of rats and to provide an experimental basis for the development of bone regeneration biomaterials.@*Methods@#This study was approved by the Animal Ethics Committee of Nanjing University. A novel photocurable composite biohydrogel was developed by constructing photoinitiators [lthium phenyl (2,4,6-trimethylbenzoyl) phosphinate, LAP], GelMA, and BMSCs. The surface morphology and elemental composition of the gel were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The compressive strength of the gel was evaluated using an electronic universal testing machine. After in vitro culture for 1, 2, and 5 days, the proliferation of the BMSCs in the hydrogels was assessed using a CCK-8 assay, and their survival and morphology were examined through confocal microscopy. A 5 mm critical bone deficiency model was generated in a rat skull. The group receiving composite hydrogel treatment was referred to as the GelMA/BMSCs group, whereas the untreated group served as the control group. At the 4th and 8th weeks, micro-CT scans were taken to measure the bone defect area and new bone index, while at the 8th week, skull samples from the defect area were subjected to H&E staining, van Gieson staining, and Goldner staining to evaluate the quality of bone regeneration and new bone formation.@*Results@#SEM observed that the solidified GelMA showed a 3D spongy gel network with uniform morphology, the porosity of GelMA was 73.41% and the pore size of GelMA was (28.75 ± 7.13) μm. EDX results showed that C and O were evenly distributed in the network macroporous structure of hydrogel. The hydrogel compression strength was 152 kPa. On the 5th day of GelMA/BMSCs culture, the cellular morphology transitioned from oval to spindle shaped under microscopic observation, accompanied by a significant increase in cell proliferation (159.4%, as determined by the CCK-8 assay). At 4 weeks after surgery, a 3D reconstructed micro-CT image revealed a minimal reduction in bone defect size within the control group and abundant new bone formation in the GelMA/BMSCs group. At 8 weeks after surgery, no significant changes were observed in the control group's bone defect area, with only limited evidence of new bone growth; however, substantial healing of skull defects was evident in the GelMA/BMSCs group. Quantitative analysis at both the 4- and 8-week examinations indicated significant improvements in the new bone volume (BV), new bone volume/total bone volume (BV/TV), bone surface (BS), and bone surface/total bone volume (BS/TV) in the GelMA/BMSCs group compared to those in the control group (P<0.05). Histological staining showed continuous and dense formation of bone tissue within the defects in the GelMA/BMSCs group and only sporadic formation of new bone, primarily consisting of fibrous connective tissue, at the defect edge in the control group.@*Conclusion@#Photocuring hydrogel-based stem cell therapy exhibits favorable biosafety profiles and has potential for clinical application by inducing new bone formation and promoting maturation within rat skull defects.

Research progress on molecular mechanism of traditional chinese medicine active ingredients interfering bone marrow mesenchymal stem cells senescence / 中国临床药理学与治疗学

The senescence of bone marrow mesenchymal stem cells (BM-MSCs) will induce age-related bone tissue degeneration and chronic inflammation, and reduce its application effect for cell therapy. More and more active ingredients of traditional chinese medicine have been proved to intervene BM - MSCs senescence, playing an important role in bone diseases prevention and treatment, and improving the therapeutic effect of BM-MSCs. In this paper, the latest research progress on the molecular mechanism of traditional chinese medicine active ingredients interfering BM-MSCs senescence was summarized, in order to provide new direction and reference basis for senescence intervention research and clinical application improvement of BM-MSCs.

Advances in the study of mesenchymal stem cells in obstructive sleep apnea hypoventilation syndrome / 中国临床药理学与治疗学

Mesenchymal stem cells (MSCs) are self-regenerating, rapidly proliferating pluripotent stem cells that depend primarily on their derived pro-angiogenic, inflammatory regulatory, and trophic factors to exert beneficial effects that attenuate deleterious inflammatory responses, reduce vascular damage, and promote tissue repair and regeneration. Obstructive sleep apnea hypoventilation syndrome (OSAHS) is a chronic disorder marked by oropharyngeal collapse during sleep, resulting in transient reduced airflow, large fluctuations in intrathoracic pressure, and intermittent hypoxia and hypercapnia. OSAHS subsequently cytokine-mediated inflammatory cascades, oxidative stress, and ischemia, recruit MSCs from inflamed and damaged tissues through MSCs-derived of anti-inflammatory and pro-angiogenic factor activity, reduce hypoxia, suppress inflammation, promote regeneration, and prevent fibrosis in OSAHS-injured tissues. In this paper, we will describe the pathogenesis of inflammation, oxidative stress, fibrosis and ischemia from the perspective of OSAHS, highlighting the current research progress on MSCs-dependent regulation of OSAHS-related pathology.

Progress in the potential therapeutic mechanism of mesenchymal stem cell-derived exosomes for liver fibrosis / 中国临床药理学与治疗学

Liver fibrosis is pathological in most chronic liver diseases. Exosomes secreted by mesenchymal stem cells (MSCs) can regulate liver fibrosis through mechanisms such as inhibition of inflammatory response and proliferation of activated hepatic stellate cells, regulation of immune cells and metabolism. Therefore, MSC-derived exosomes can be used as a cell-free therapy for chronic liver disease, expanding new ideas for the treatment of chronic liver disease. Recent researches on MSC-derived exosomes in the treatment of liver fibrosis are reviewed in this article.

Effect of miR-141-5p/ZNF705A on adhesion of bone marrow mesenchymal stem cells in chronic myeloid leukemia cell-derived exosomes / 中国药理学通报

Aim To investigate the effect of miR-141-5p/ZNF705A in chronic myeloid leukemia(CML)cell-derived exosome(Exo)on the adhesion of bone marrow mesenchymal stem cells(BMSCs). Methods The morphology and size of Exo in peripheral blood from CML patients and K562 cells were examined by electron microscopy and NTA particle size analysis. The expressions of Exo and BMSCs marker molecules and adhesion proteins in K562 cells were detected by qRT-PCR and Western blot before and after transfection. The adhesion ability of BMSCs was detected by cell adhesion assay, and the cellular activity of BMSCs was examined using CCK-8. miR-141-5p binding to ZNF705A was detected by luciferase assay. Results qRT-PCR results showed that miR-141-5p expression was significantly reduced in both CML patients and K562 cell-derived Exo. qRT-PCR, Western blot and other results showed that BMSCs in CML patients had significantly reduced the expression of adhesion proteins CD44 and CXCL12, and were able to phagocytose K562 cell-derived Exo. Further, K562-derived Exo was found to reduce CD44 and CXCL12 expression and adhesion in Exo-promoted BMSCs compared with CD34+ cells. Meanwhile, the results of dual luciferase reporter assay verified that miR-141-5p targeted binding to ZNF705A. Finally, we found ZNF705A could be targeted by up-regulating miR-141-5p expression in Exo of K562 cells, which in turn inhibited the adhesion of BMSCs. Conclusions K562 cells down-regulate miR-141-5p expression in Exo and inhibit the adhesion function of BMSCs by targeting ZNF705A, thus regulating the bone marrow hematopoietic function in CML patients.

Optimization of extraction process of flavonoids from Broussonetia papyrifera leaves and its antioxidant effect on mouse epidermal stem cells / 中国生物制品学杂志

@#Objective To optimize the extraction process of flavonoids from Broussonetia papyrifera leaves and explore the antioxidant effect of flavonoids on mouse epidermal stem cells.Methods The extraction process of flavonoids from Broussonetia papyrifera leaves was optimized by single factor experiment,including the liquid-solid ratio(15:1,20:1,25:1,30:1and 35:1),sodium hydroxide(NaOH) concentration(0.2%,0.4%,0.6%,0.8% and 1.0%),pH value(2.5,3.0,3.5,4.0and 4.5) and extraction temperature(60,65,70,75 and 80℃).Based on the results of single factor experiment,the optimal extraction process was determined by orthogonal test with the mass fraction of flavonoids as the evaluation index.CD49f~+/CD71~-mouse epidermal stem cells were isolated and cultivated by immunomagnetic bead method,and the effects of flavonoids on the cell relative viability and the contents of reduced glutathione(GSH) and malondialdehyde(MDA) were detected.Results The optimal extraction conditions of flavonoids were liquid-solid ratio of 30:1,0.6% NaOH,pH 4.5and extraction temperature of 75 ℃.Under these conditions,the average mass fraction of flavonoids extracted was 1.47%.Compared with the negative control group,when the flavonoids final concentration was 25 and 50 μg/mL,the cell relative viability increased significantly(F=1.427 and 13.747 respectively,each P <0.01);when the final concentration of flavonoids was 12.5,25 and 50 μg/mL,the content of GSH increased significantly(F=0.044,0.291 and 2.577 respectively,each P <0.05) and the content of MDA decreased significantly(F=3.568,4.909 and 1.400 respectively,each P <0.05).Conclusion The optimized extraction process of flavonoids from B.papyrifera leaves was stable and reliable,which is beneficial to the reuse of remaining stock solution after processing,and the extracted flavonoids can promote the proliferation of mouse epidermal stem cells and perform antioxidant activity.

Role of mesenchymal stem cells and their exosomes in the treatment of drug-induced liver injury / 临床肝胆病杂志

The incidence rate of drug-induced liver injury （DILI） is increasing year by year with unknown mechanisms， and the treatment methods for DILI mainly include drugs， liver support systems， and liver transplantation， all of which have certain limitations. Therefore， the search for safer and more effective treatment methods has become a research hotspot at present. Studies have shown that mesenchymal stem cells and their exosomes can alleviate liver injury by reducing liver inflammation， promoting hepatocyte proliferation and regeneration， inhibiting the apoptosis of hepatocytes， improving oxidative stress， and regulating immunity. This article briefly reviews the role of mesenchymal stem cells and their exosomes in the treatment of DILI， so as to provide a reference for further research.

Effect of human umbilical cord mesenchymal stem cells in treatment of mice with liver fibrosis and its mechanism / 临床肝胆病杂志

ObjectiveTo investigate the effect of human umbilical cord mesenchymal stem cells （hUCMSCs） in the treatment of mice with liver fibrosis and its mechanism. MethodsA total of 18 specific pathogen-free C57BL/6 mice， aged 6 weeks， were selected and divided into control group （n=6）， carbon tetrachloride （CCl4） model group （CCl4 group， n=6）， and hUCMSCs treatment group （MSC group， n=6） using a random number table. The mice in the CCl4 group and the MSC group were given intraperitoneal injection of CCl4 solution to establish a mouse model of liver fibrosis， while those in the control group were injected with the same dose of corn oil， and the mice in the MSC group were injected with hUCMSCs via the caudal vein during the injection of CCl4. At the end of week 8， mouse serum was collected， and the mice were sacrificed to collect and fix the liver. Enzyme-linked immunosorbent assay was used to measure the levels of inflammatory factors； an automatic biochemical detector was used to measure liver function parameters； HE staining， Masson staining， Sirius Red staining， and α-SMA immunofluorescence assay were used to evaluate liver fibrosis. Hepatic stellate cells （HSCs） stimulated by TGF-β were co-cultured with hUCMSCs in the medium with or without chitinase-3 like-protein-1 （CHI3L1）， and Western blot was used to measure the expression levels of proteins. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the Dunnett’s t-test was used for further comparison between two groups. ResultsMasson staining and Sirius Red staining showed that the CCl4 group had a significantly higher degree of fibrosis than the control group （both P<0.05）， and the MSC group had significant alleviation of fibrosis compared with the CCl4 group （both P<0.05）. Compared with the control group， the CCl4 group had significant increases in the levels of interleukin-1β， interleukin-6 （IL-6）， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， and alkaline phosphatase （ALP） （all P<0.05）， and compared with the CCl4 group， the MSC group had significant reductions in the levels of IL-6， AST， ALT， and ALP （all P<0.05）. The CCl4 group had significantly higher expression levels of CHI3L1 and α-SMA than the control group and the MSC group （all P<0.05）. The cell culture experiment showed that the MSC+HSC group had a significantly higher expression level of Bax than the HSC group and the MSC+CHI3L1 group （both P<0.05）， suggesting that CHI3L1 reversed the pro-apoptotic effect of MSC on activated HSCs. ConclusionThis study shows that hUCMSCs can improve liver fibrosis in mice， possibly by inhibiting CHI3L1 to promote the apoptosis of HSCs.

Analysis on Current Situation and Ethical Problems of Stem Cell Clinical Research in China / 中国医学伦理学

It is worth pondering how to seek advantages and avoid disadvantages in stem cell clinical research and give full play to the advantages of technology for the benefit of mankind. Through the analysis of the status of stem cell clinical research, including technology and related management methods, proposed the main problems existing in stem cell research, such as the risks of technological uncertainty, ambiguity between research and treatment, over-treatment and technological innovation. Then this paper discussed the ethical and legal risks of stem cell clinical research in China, mainly related to the problems that the construction of laws and regulations is lagging behind, the regulatory challenges of administrative departments are large, the ethical awareness of researchers needs to be further improved, the principle of fairness and justice is not taken into account, the research platform construction of medical institutions is not in place and the protection system of subjects is imperfect, and the organization construction and review capacity of the ethics committee is still lacking.

Research progress on dedifferentiated fat cells and their application in oral and maxillofacial bone tissue engineering / 口腔疾病防治

@#The identification of suitable seed cells represents a critical scientific problem to be solved in the field of oral and maxillofacial bone tissue regeneration. The application of adipose-derived stem cells (ASCs) in tissue and organ repair and regeneration has been studied extensively. In recent years, dedifferentiated fat (DFAT) cells have also shown broad application prospects in the field of bone tissue engineering. DFAT cells express stem cell-related markers and have the potential to differentiate into adipocytes, osteoblasts, chondrocytes, nerve cells, cardiomyocytes and endothelial cells. In addition, DFAT cells also have the advantages of minimally invasive acquisition, strong proliferation and high homogeneity. Currently, all studies involving the application of DFAT cells in scaffold-based and scaffold-free bone tissue engineering can confirm their effectiveness in promoting bone regeneration. However, cytological research still faces some challenges, including relatively low cell culture purity, unclear phenotypic characteristics and undefined dedifferentiation mechanisms. It is believed that with the continuous development and improvement of isolation, culture, identification and directional induction of osteogenic differentiation methods, DFAT cells are expected to become excellent seed cells in the field of oral and maxillofacial bone tissue engineering in the future.

Therapeutic effect of transplantation of bone marrow mesenchymal stem cells co-cultured with bone marrow M2 macrophages on a rat model of liver cirrhosis / 临床肝胆病杂志

ObjectiveTo investigate the effect of transplantation of bone marrow mesenchymal stem cells （BMSCs） co-cultured with bone marrow-derived M2 macrophages （M2-BMDMs）， named as BMSCM2， on a rat model of liver cirrhosis induced by carbon tetrachloride （CCl4）/2-acetaminofluorene （2-AAF）. MethodsRat BMDMs were isolated and polarized into M2 phenotype， and rat BMSCs were isolated and co-cultured with M2-BMDMs at the third generation to obtain BMSCM2. The rats were given subcutaneous injection of CCl4 for 6 weeks to establish a model of liver cirrhosis， and then they were randomly divided into model group （M group）， BMSC group， and BMSCM2 group， with 6 rats in each group. A normal group （N group） with 6 rats was also established. Since week 7， the model rats were given 2-AAF by gavage in addition to the subcutaneous injection of CCl4. Samples were collected at the end of week 10 to observe liver function， liver histopathology， and hydroxyproline （Hyp） content in liver tissue， as well as changes in the markers for hepatic stellate cells， hepatic progenitor cells， cholangiocytes， and hepatocytes. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the N group， the M group had significant increases in the activities of serum alanine aminotransferase （ALT） and aspartate aminotransferase （AST） （P<0.01）； compared with the M group， the BMSC and BMSCM2 groups had significant reductions in ALT and AST （P<0.01）， and the BMSCM2 group had significantly better activities than the BMSC group （P<0.05）. Compared with the N group， the M group had significant increases in Hyp content and the mRNA and protein expression levels of alpha-smooth muscle actin （α-SMA） in the liver （P<0.01）； compared with the M group， the BMSC and BMSCM2 groups had significant reductions in Hyp content and the expression of α-SMA （P<0.05）， and the BMSCM2 group had a significantly lower level of α-SMA than the BMSC group （P<0.01）. Compared with the N group， the M group had significant increases in the mRNA expression levels of the hepatic progenitor cell markers EpCam and Sox9 and the cholangiocyte markers CK7 and CK19 （P<0.01） and significant reductions in the expression levels of the hepatocyte markers HNF-4α and Alb （P<0.01）； compared with the M group， the BMSC and BMSCM2 groups had significant reductions in the mRNA expression levels of EpCam， Sox9， CK7， and CK19 （P<0.05） and significant increases in the mRNA expression levels of HNF-4α and Alb （P<0.05）， and compared with the BMSC group， the BMSCM2 group had significant reductions in the mRNA expression levels of EpCam and CK19 （P<0.05） and significant increase in the expression level of HNF-4α （P<0.05）. ConclusionM2-BMDMs can enhance the therapeutic effect of BMSCs on CCl4/2-AAF-induced liver cirrhosis in rats， which provides new ideas for further improving the therapeutic effect of BMSCs on liver cirrhosis.

Research progress of mesenchymal stem cell-derived exosomes in the treatment of dry eye / 国际眼科杂志(Guoji Yanke Zazhi)

Exosomes are extracellular vesicles that facilitate cellular communication by transmitting biomolecules and altering the biochemical characteristics of receptor cells. Mesenchymal stem cell-derived exosomes(MSC-Exos)are lipid bilayer vesicles secreted by mesenchymal stem cells(MSCs). These exosomes have similar functions to MSCs and contain bioactive substances such as proteins, lipids, and nucleic acids. MSC-Exos play a vital role in intercellular communication and are involved in essential physiological processes including immune regulation, tissue damage repair, and angiogenesis promotion. Consequently, they have gained significant attention in research, particularly in the treatment of immune inflammatory diseases, ischemic diseases, and other related fields. This article provides an in-depth analysis of the potential treatment mechanisms for dry eye, focusing on the pathogenesis of the condition, including inflammatory reactions, nerve regeneration, and tissue repair. The objective is to establish a foundation for the application of MSC-Exos in the treatment of dry eye, thereby offering a valuable reference for the future clinical applications.

Potential of human induced pluripotent stem cells differentiating into corneal epithelial cells in simulated limbal stem cell microenvironment / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the potential of human induced pluripotent stem cells(hiPSCs)differentiating into corneal epithelial cells in the simulated limbal stem cells(LSCs)microenvironment.METHODS: The hiPSC cell lines were established in vitro, and hiPSCs were co-cultured with corneal stromal cells in transwell system, which simulated the LSC microenvironment. Bone morphogenetic protein 4(BMP4)and a specific transforming growth factor β inhibitor(SB431542)were added to improve the differentiation efficacy. The expression of corneal epithelial cell-specific markers CK3 and CK12, corneal epithelial cell precursor CK15, and the limbal stem cell markers ABCG5 were determined by immunofluorescence staining and flow cytometry.RESULTS: The hiPSCs were actively proliferated in vitro, and immunofluorescence staining showed positive stem cell-specific markers OCT4, SOX2, TRA-1-60 and NANOG. Furthermore, hiPSCs co-cultured with corneal stromal cells exhibited LSCs markers ABCG5 and corneal epithelial cell precursor markers CK15 were positive; however, corneal epithelial cell markers CK3 and CK12 were negative. With the addition of BMP4 and SB431542, hiPSCs showed positive expression of CK3, and the CK3 expression increased over the time.CONCLUSION: With the addition of SB431542 and BMP4, hiPSCs cultured in simulated LSCs microenvironment could differentiate into corneal epithelial cells.

Research progress on immunomodulatory properties of periodontal ligament stem cells / 口腔疾病防治

@#Periodontal ligament stem cells (PDLSCs) have the potential for multidirectional differentiation and are the preferred seed cells for periodontal tissue regeneration. In recent years, a large number of studies have confirmed that PDLSCs also possess broad immunomodulatory properties. Therefore, in-depth exploration of their specific molecular mechanisms is of great significance for the treatment of periodontitis. The aim of this paper is to summarize the research progress on the regulation of PDLSCs on various immune cells and the effect of the inflammatory environment on the immune characteristics of PDLSCs to provide an important theoretical basis for the allotransplantation of PDLSCs and improve the therapeutic effect of periodontal tissue regeneration. Studies have shown that PDLSCs possess a certain degree of immunosuppressive effect on both innate and acquired immune cells, and inflammatory stimulation may lead to the impairment of the immunoregulatory properties of PDLSCs. However, current studies are mainly limited to in vitro cell tests and lack in-depth studies on the immunomodulatory effects of PDLSCs in vivo. In vivo studies based on cell lineage tracing and conditional gene knockout technology may become the main directions for future research.

Advances in mesenchymal stem cells therapy for tendinopathies / 中华创伤杂志(英文版)

Tendinopathies are chronic diseases of an unknown etiology and associated with inflammation. Mesenchymal stem cells (MSCs) have emerged as a viable therapeutic option to combat the pathological progression of tendinopathies, not only because of their potential for multidirectional differentiation and self-renewal, but also their excellent immunomodulatory properties. The immunomodulatory effects of MSCs are increasingly being recognized as playing a crucial role in the treatment of tendinopathies, with MSCs being pivotal in regulating the inflammatory microenvironment by modulating the immune response, ultimately contributing to improved tissue repair. This review will discuss the current knowledge regarding the application of MSCs in tendinopathy treatments through the modulation of the immune response.

Research advances on stem cell-based treatments in animal studies and clinical trials of lymphedema / 中国修复重建外科杂志

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.