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.

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.

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.

Endometrial mesenchymal stromal/stem cells improve regeneration of injured endometrium in mice

BACKGROUND: The monthly regeneration of human endometrial tissue is maintained by the presence of human endometrial mesenchymal stromal/stem cells (eMSC), a cell population co-expressing the perivascular markers CD140b and CD146. Endometrial regeneration is impaired in the presence of intrauterine adhesions, leading to infertility, recurrent pregnancy loss and placental abnormalities. Several types of somatic stem cells have been used to repair the damaged endometrium in animal models, reporting successful pregnancy. However, the ability of endometrial stem cells to repair the damaged endometrium remains unknown. METHODS: Electrocoagulation was applied to the left uterine horn of NOD/SCID mice causing endometrial injury. Human eMSC or PBS was then injected into the left injured horn while the right normal horn served as controls. Mice were sacrificed at different timepoints (Day 3, 7 and 14) and the endometrial morphological changes as well as the degree of endometrial injury and repair were observed by histological staining. Gene expression of various inflammatory markers was assessed using qPCR. The functionality of the repaired endometrium was evaluated by fertility test. RESULTS: Human eMSC successfully incorporated into the injured uterine horn, which displayed significant morphological restoration. Also, endometrium in the eMSC group showed better cell proliferation and glands formation than the PBS group. Although the number of blood vessels were similar between the two groups, gene expression of VEGF-α significantly increased in the eMSC group. Moreover, eMSC had a positive impact on the regeneration of both stromal and epithelial components of the mouse endometrium, indicated by significantly higher vimentin and CK19 protein expression. Reduced endometrial fibrosis and down-regulation of fibrosis markers were also observed in the eMSC group. The eMSC group had a significantly higher gene expression of anti-inflammatory factor Il-10 and lower mRNA level of pro-inflammatory factors Ifng and Il-2, indicating the role of eMSC in regulation of inflammatory reactions. The eMSC group showed higher implantation sites than the PBS group, suggesting better endometrial receptivity with the presence of newly emerged endometrial lining. CONCLUSIONS: Our findings suggest eMSC improves regeneration of injured endometrium in mice.

Avances en endodoncia regenerativa: reporte de caso con uso de la membrana amniótica humana / Advances in regenerative endodontics: report of a case using a human amniotic membrane

Los procedimientos endodónticos regenerativos (REPs) representan una evolución significativa en el campo de la endodoncia, buscando no sólo tratar la infección o lesión presente en el diente, sino tam-bién promover la regeneración de los tejidos denta-rios afectados. El presente caso clínico muestra un incisivo lateral superior izquierdo con apexogénesis incompleta y diagnóstico de absceso alveolar crónico reagudizado en una paciente de 22 años, en el que se aplicó un procedimiento de endodoncia regenerativa (REPs). La estrategia terapéutica elegida se basó en los principios de ingeniería tisular, incorporando la novedosa aplicación de la membrana amniótica hu-mana liofilizada esterilizada como andamio bioactivo intraconducto. Las evaluaciones clínicas, radiográ-ficas y tomográficas a corto, mediano y largo plazo revelaron el éxito de la terapia. La resolución exitosa mostró en los controles a la pieza dentaria asintomá-tica, con una notable remisión de la patología apical, aumento de la longitud radicular y disminución del calibre apical. Se ha podido destacar la eficacia de los REPs, con una exitosa aplicabilidad de la membra-na amniótica como andamio innovador (AU)

Regenerative endodontic procedures (REPs) represent a significant evolution in the field of endodontics, aiming not only to address the infection or injury within the tooth, but also to promote the regeneration of the affected dental tissues. In this clinical case, an upper left lateral incisor with incomplete apexogenesis and diagnosis of acute exacerbation of a chronic periapical lesion in a 22-year-old patient is presented. A regenerative endodontic procedure (REPs) was applied. The chosen therapeutic strategy was based on tissue engineering principles, incorporating the innovative use of sterilized lyophilized human amniotic membrane as an intraconduct bioactive scaffold. Clinical, radiographic, and tomographic assessments at short, medium, and long-term follow-up revealed the success of the therapy. Successful resolution demonstrated an asymptomatic tooth in the follow-up, with a notable resolution of apical pathology, increased root length, and decreased apical caliber. The effectiveness of REPs has been highlighted, demonstrating the successful applicability of amniotic membrane as an innovative scaffold (AU)

Cobalt Chloride as a Hypoxia Mimicking Agent Induced HIF-1α and mTOR Expressions of Human Umbilical Cord Mesenchymal Stem Cells

ABSTRACT Objective: To assess the effects of cobalt chloride (CoCl2) as a hypoxia mimicking agent on human umbilical cord mesenchymal stem cells (hUCMSCs) expression of HIF-1α and mTOR for use in regenerative dentistry. Material and Methods: Human umbilical cord mesenchymal stem cells were isolated and then cultured. The characteristics of stemness were screened and confirmed by flow cytometry. The experiment was conducted on hypoxia (H) and normoxia (N) groups. Each group was divided and incubated into 24-, 48-, and 72-hours observations. Hypoxic treatment was performed using 100 µM CoCl2 on 5th passage cells in a conventional incubator (37°C; 5CO2). Then, immunofluorescence of HIF-1α and mTOR was done. Data was analyzed statistically using One-way ANOVA and Tukey's HSD. Results: Significant differences were found between normoxic and hypoxic groups on HIF-1α (p=0.015) and mTOR (p=0.000) expressions. The highest HIF-1α expression was found at 48 hours in the hypoxia group, while for mTOR at 24 hours in the hypoxia group. Conclusion: Hypoxia using cobalt chloride was able to increase human umbilical cord mesenchymal stem cells expression of HIF-1α and mTOR.

Influence of the addition of nanohydroxyapatite to scaffolds on proliferation and differentiation of human mesenchymal stem cells: a systematic review of in vitro studies

One of the main challenges of tissue engineering in dentistry is to replace bone and dental tissues with strategies or techniques that simulate physiological tissue repair conditions. This systematic review of in vitro studies aimed to evaluate the influence of the addition of nanohydroxyapatite (NHap) to scaffolds on cell proliferation and osteogenic and odontogenic differentiation of human mesenchymal stem cells. In vitro studies on human stem cells that proliferated and differentiated into odontogenic and osteogenic cells in scaffolds containing NHap were included in this study. Searches in PubMed/MEDLINE, Scopus, Web of Science, OpenGrey, ProQuest, and Cochrane Library electronic databases were performed. The total of 333 articles was found across all databases. After reading and analyzing titles and abstracts, 8 articles were selected for full reading and extraction of qualitative data. Results showed that despite the large variability in scaffold composition, NHap-containing scaffolds promoted high rates of cell proliferation, increased alkaline phosphatase (ALP) activity during short culture periods, and induced differentiation, as evidenced by the high expression of genes involved in osteogenesis and odontogenesis. However, further studies with greater standardization regarding NHap concentration, type of scaffolds, and evaluation period are needed to observe possible interference of these criteria in the action of NHap on the proliferation and differentiation of human stem cells.

Common mental disorders in hematopoietic stem cell transplant patients: a scoping review / Trastornos mentales comunes en pacientes con trasplante de células madre hematopoyéticas: revisión del alcance / Transtornos mentais comuns em pacientes transplantados com células-tronco hematopoéticas: revisão de escopo

ABSTRACT Objective: to map common recurrent mental disorders in patients undergoing hematopoietic stem cell transplantation. Methods: this is a scoping review carried out in January 2022 in electronic databases and repositories of dissertations and thesis. Studies that answered the research question, met the objective of the study and were available in full electronically, in any language, were included. Results: the sample consisted of 28 studies, 14 of which were published in the United States of America. The common mental disorders found were depressive, anxiety, post-traumatic stress and mood disorders. Twenty symptoms were mentioned, among the most prevalent are fatigue and sleep disorders/insomnia. Conclusions: the difficulty and importance of carrying out the differential diagnosis of these disorders were highlighted, since their symptoms can be confused with other health problems and have a strong potential to interfere with patients' evolution.

RESUMEN Objetivo: mapear los trastornos mentales recurrentes comunes en pacientes sometidos a trasplante de células madre hematopoyéticas. Métodos: se trata de una revisión de alcance realizada en enero de 2022 en bases de datos electrónicas y repositorios de disertaciones y tesis. Se incluyeron publicaciones que respondieron a la pregunta de investigación, cumplieron con el objetivo del estudio y estaban disponibles en su totalidad en formato electrónico, en cualquier idioma. Resultados: la muestra estuvo compuesta por 28 estudios, 14 de los cuales fueron publicados en los Estados Unidos de América. Los trastornos mentales comunes encontrados fueron depresión, ansiedad, estrés postraumático y trastornos del estado de ánimo. Se mencionaron 20 síntomas, entre los más prevalentes se encuentran fatiga y trastornos del sueño/insomnio. Conclusiones: se destacó la dificultad e importancia de realizar el diagnóstico diferencial de estos trastornos, ya que sus síntomas pueden confundirse con otros problemas de salud y tienen un fuerte potencial de interferir en la evolución del paciente.

RESUMO Objetivo: mapear os transtornos mentais comuns recorrentes em pacientes submetidos ao transplante de células-tronco hematopoéticas. Métodos: trata-se de revisão de escopo realizada em janeiro de 2022 em bases de dados eletrônicas e repositórios de dissertações e tese. Foram incluídas publicações que respondessem à questão de pesquisa, atendessem ao objetivo do estudo e que estivessem disponíveis na íntegra em meio eletrônico, em qualquer idioma. Resultados: a amostra foi composta por 28 estudos, dos quais 14 foram publicados nos Estados Unidos da América. Os transtornos mentais comuns encontrados foram os transtornos depressivos, de ansiedade, estresse pós-traumático e de humor. Foram citados 20 sintomas, entre os mais prevalentes estão a fadiga e distúrbios do sono/insônia. Conclusões: evidenciaram-se a dificuldade e a importância de realizar o diagnóstico diferencial desses transtornos, uma vez que seus sintomas podem ser confundidos com outros problemas de saúde e têm forte potencial para interferir na evolução do paciente.

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.

Study on injectable chitosan hydrogel with tendon-derived stem cells for enhancing rotator cuff tendon-to-bone healing / 中国修复重建外科杂志

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.

Impact of lithocholic acid on the osteogenic and adipogenic differentiation balance of bone marrow mesenchymal stem cells / 中国修复重建外科杂志

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.

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.

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.