Neurological manifestations of SARS-CoV-2 infection in children in Taiwan: A cross-section, multicenter study.

BACKGROUND: The SARS-CoV-2 virus has been a global public health threat since December 2019. This study aims to investigate the neurological characteristics and risk factors of coronavirus disease 2019 (COVID-19) in Taiwanese children, using data from a collaborative registry. METHODS: A retrospective, cross-sectional, multi-center study was done using an online network of pediatric neurological COVID-19 cohort collaborative registry. RESULTS: A total of 11160 COVID-19-associated emergency department (ED) visits and 1079 hospitalizations were analyzed. Seizures were the most common specific neurological symptom, while encephalitis and acute disseminated encephalomyelitis (ADEM) was the most prevalent severe involvement. In ED patients with neurological manifestations, severe neurological diagnosis was associated with visual hallucination, seizure with/without fever, behavior change, decreased GCS, myoclonic jerk, decreased activity/fatigue, and lethargy. In hospitalized patients with neurological manifestations, severe neurological diagnosis was associated with behavior change, visual hallucination, decreased GCS, seizure with/without fever, myoclonic jerk, fatigue, and hypoglycemia at admission. Encephalitis/ADEM was the only risk factor for poor neurological outcomes at discharge in hospitalized patients. CONCLUSION: Neurological complications are common in pediatric COVID-19. Visual hallucination, seizure, behavior change, myoclonic jerk, decreased GCS, and hypoglycemia at admission are the most important warning signs of severe neurological involvement such as encephalitis/ADEM.

Psychosocial stress in children with Tourette syndrome and chronic tic disorder.

BACKGROUND: This study aimed to understand the longitudinal relationship between psychosocial stress with tic exacerbation in children with Tourette syndrome (TS) and chronic tic disorder. METHODS: Consecutive ratings of tic severity as well as child and parental reports of psychosocial stress were obtained for 373 children (296 males, 77 females; mean age 9y 5mo; SD 3y 3mo) with TS and chronic tic disorder between January 2018 and December 2020. The Yale Global Tic Severity Scale (YGTSS) global severity score, total tic score, and impairment rating were calculated. The stressful events and YGTSS measurements were used and treated as time-varying variables in the analyses. Models that controlled for non-independence among the repeated observations using a random intercept and random slope model were employed. Each participant was treated as a random factor in the modelling. RESULTS: Family-related stress, personal relationship stress and school-related stress were independently associated with increasing YGTSS global severity, total tic score, and impairment rating over time. An increased number of stressful events were associated with increased severity of tics. CONCLUSION: Family, personal relationships, and school-related stress were consistently associated with the exacerbation of tics. Managing these stressful events is important in the treatment of TS and chronic tic disorder.

Biomimetic Intrafibrillar Mineralization of Native Tendon for Soft-Hard Interface Integration by Infiltration of Amorphous Calcium Phosphate Precursors.

Soft and hard tissues possess distinct biological properties. Integrating the soft-hard interface is difficult due to the inherent non-osteogenesis of soft tissue, especially of anterior cruciate ligament and rotator cuff reconstruction. This property makes it difficult for tendons to be mineralized and integrated with bone in vivo. To overcome this challenge, a biomimetic mineralization strategy is employed to engineer mineralized tendons. The strategy involved infiltrating amorphous calcium phosphate precursors into collagen fibrils, resulting in hydroxyapatite deposition along the c-axis. The mineralized tendon presented characteristics similar to bone tissue and induced osteogenic differentiation of mesenchymal stem cells. Additionally, the interface between the newly formed bone and tendon is serrated, suggesting a superb integration between the two tissues. This strategy allows for biomineralization of tendon collagen and replicating the hallmarks of the bone matrix and extracellular niche, including nanostructure and inherent osteoinductive properties, ultimately facilitating the integration of soft and hard tissues.

Animal model for tendinopathy.

Background: Tendinopathy is a common motor system disease that leads to pain and reduced function. Despite its prevalence, our mechanistic understanding is incomplete, leading to limited efficacy of treatment options. Animal models contribute significantly to our understanding of tendinopathy and some therapeutic options. However, the inadequacies of animal models are also evident, largely due to differences in anatomical structure and the complexity of human tendinopathy. Different animal models reproduce different aspects of human tendinopathy and are therefore suitable for different scenarios. This review aims to summarize the existing animal models of tendinopathy and to determine the situations in which each model is appropriate for use, including exploring disease mechanisms and evaluating therapeutic effects. Methods: We reviewed relevant literature in the PubMed database from January 2000 to December 2022 using the specific terms ((tendinopathy) OR (tendinitis)) AND (model) AND ((mice) OR (rat) OR (rabbit) OR (lapin) OR (dog) OR (canine) OR (sheep) OR (goat) OR (horse) OR (equine) OR (pig) OR (swine) OR (primate)). This review summarized different methods for establishing animal models of tendinopathy and classified them according to the pathogenesis they simulate. We then discussed the advantages and disadvantages of each model, and based on this, identified the situations in which each model was suitable for application. Results: For studies that aim to study the pathophysiology of tendinopathy, naturally occurring models, treadmill models, subacromial impingement models and metabolic models are ideal. They are closest to the natural process of tendinopathy in humans. For studies that aim to evaluate the efficacy of possible treatments, the selection should be made according to the pathogenesis simulated by the modeling method. Existing tendinopathy models can be classified into six types according to the pathogenesis they simulate: extracellular matrix synthesis-decomposition imbalance, inflammation, oxidative stress, metabolic disorder, traumatism and mechanical load. Conclusions: The critical factor affecting the translational value of research results is whether the selected model is matched with the research purpose. There is no single optimal model for inducing tendinopathy, and researchers must select the model that is most appropriate for the study they are conducting. The translational potential of this article: The critical factor affecting the translational value of research results is whether the animal model used is compatible with the research purpose. This paper provides a rationale and practical guide for the establishment and selection of animal models of tendinopathy, which is helpful to improve the clinical transformation ability of existing models and develop new models.

Mid-Long-Term Effect of Metabolic Surgery on Type 2 Diabetes in Nonobese Patients: a Meta-analysis.

BACKGROUND: This study aimed to perform a meta-analysis regarding the mid-long-term effect (≥ 2-year follow-up) of metabolic surgery on T2DM in non-obese patients. METHODS: PubMed, EMBASE and CENTRAL databases were searched for clinical studies from inception to March 2023. Stata 12.0 was used for data aggregation. Sensitivity, subgroup, and meta-regression analyses were performed when feasible. RESULTS: This meta-analysis included 18 articles involving 548 patients. A pooled rate of 47.5% of T2DM remission was found after metabolic surgery. To be more specific, 83.5% was obtained for hemoglobin A1c (HbA1c) < 7.0%, 45.1% for HbA1c < 6.5%, and 40.4% for HbA1c < 6.0%. Subgroup analysis showed that one-anastomosis gastric bypass (OAGB) had a higher remission rate (93.9%) than other surgeries. Studies conducted in America had a higher remission rate (61.4%) than in Asia (43.6%). Meta-regression analysis displayed that publication year, number of patients, study design, preoperative age, BMI, and quality assessment score were not significantly associated with T2DM remission rate. Additionally, metabolic surgery could result in significant reductions in BMI (-4.133 kg/m2), weight (-9.874 kg), HbA1c (-1.939%), fasting blood glucose, fasting C-peptide, and fasting insulin. However, metabolic surgery seemed to have poorer glycemic control in non-obese than obese T2DM patients. CONCLUSION: A moderate mid-long-term effect of T2DM remission was observed after metabolic surgery in non-obese patients. However, we still need more prospective multi-institutional studies using the same definitions for diabetes and the same surgical technique for the surgery. Without this, the exact role of bariatric surgery in non-obese patients is unanswered.

Application of Drug Testing Platforms in Circulating Tumor Cells and Validation of a Patient-Derived Xenograft Mouse Model in Patient with Primary Intracranial Ependymomas with Extraneural Metastases.

Primary intracranial ependymoma is a challenging tumor to treat despite the availability of multidisciplinary therapeutic modalities, including surgical resection, radiotherapy, and adjuvant chemotherapy. After the completion of initial treatment, when resistant tumor cells recur, salvage therapy needs to be carried out with a more precise strategy. Circulating tumor cells (CTCs) have specifically been detected and validated for patients with primary or recurrent diffused glioma. The CTC drug screening platform can be used to perform a mini-invasive liquid biopsy for potential drug selection. The validation of potential drugs in a patient-derived xenograft (PDX) mouse model based on the same patient can serve as a preclinical testing platform. Here, we present the application of a drug testing model in a six-year-old girl with primary ependymoma on the posterior fossa, type A (EPN-PFA). She suffered from tumor recurrence with intracranial and spinal seeding at 2 years after her first operation and extraneural metastases in the pleura, lung, mediastinum, and distant femoral bone at 4 years after initial treatment. The CTC screening platform results showed that everolimus and entrectinib could be used to decrease CTC viability. The therapeutic efficacy of these two therapeutic agents has also been validated in a PDX mouse model from the same patient, and the results showed that these two therapeutic agents significantly decreased tumor growth. After precise drug screening and the combination of focal radiation on the femoral bone with everolimus chemotherapy, the whole-body bone scan showed significant shrinkage of the metastatic tumor on the right femoral bone. This novel approach can combine liquid biopsy, CTC drug testing platforms, and PDX model validation to achieve precision medicine in rare and challenging tumors with extraneural metastases.

Change in Adipokines and Gastrointestinal Hormones After Bariatric Surgery: a Meta-analysis.

PURPOSE: The study aimed to perform a meta-analysis about the change in adipokines and gastrointestinal hormones after bariatric surgery in patients with obesity. MATERIALS AND METHODS: We searched the Cochrane Central Register of Controlled Trials, EMBASE, and PubMed for related articles and used Review Manager 5.4 for data aggregation. Sensitivity and subgroup analysis were also conducted when feasible. RESULTS: As a result, 95 articles involving 6232 patients were included in the meta-analysis. After bariatric surgery, the levels of leptin, ghrelin, C-reactive protein (CRP), interleukin-6 (IL-6), high-sensitivity C-reactive protein (Hs-CRP), tumor necrosis, factor-α (TNF-α), and interleukin-1ß (IL-1ß) reduced, while adiponectin, glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) levels increased significantly. Subgroup analysis indicated that there was a more significant reduction in leptin level with a longer follow-up time. OAGB had a greater effect on increasing adiponectin level compared with other procedures. SG procedure would bring about reduced ghrelin, while BPD resulted in increased ghrelin. Meta-regression analysis found that publication year, study design, number of patients, preoperative age, preoperative BMI, and quality assessment score were not significantly related to change in leptin, adiponectin, and ghrelin levels. CONCLUSION: Bariatric surgery was associated with a significant decrease in leptin, ghrelin, CRP, IL-6, Hs-CRP, TNF-α, and IL-1ß, as well as increase in adiponectin, GLP-1, and PYY levels.

Cell-subpopulation alteration and FGF7 activation regulate the function of tendon stem/progenitor cells in 3D microenvironment revealed by single-cell analysis.

Three dimensional (3D) microenvironments more accurately replicate native microenvironments for stem cell maintenance and function compared with two dimensional (2D) microenvironments. However, the molecular mechanisms by which 3D microenvironments regulate stem cell function remain largely unexplored at the single-cell level. Here, using a single-cell analysis and functional analysis, we found not all cell-subpopulations respond to 3D microenvironments based on a systematically 3D gelatin microcarrier culture system we developed for the expansion and function maintenance of hTSPCs. 3D microenvironments alter the cell-subpopulation distribution of human tendon stem/progenitor cells (hTSPCs) by improving the proportion of ICAM1+ITGB8+ and FGF7+CYGB+ subpopulations. We also revealed the activated FGF7 signaling in the two subpopulations is responsible for the enhanced tenogenesis of hTSPCs through cell-cell interactions. The hTSPCs cultured in 3D niche with a specific cell-subpopulation structure exhibited superior stem-cell characteristics and functions both in vitro and in vivo. Together, our study demonstrates that 3D microenvironments can regulate stem-cell function by modulating the critical cell subpopulation and identifies FGF7 as a novel regulator for tenogenic differentiation and tendon regeneration.

Single-cell RNA-seq reveals functionally distinct biomaterial degradation-related macrophage populations.

Macrophages play crucial roles in host tissue reaction to biomaterials upon implantation in vivo. However, the complexity of biomaterial degradation-related macrophage subpopulations that accumulate around the implanted biomaterials in situ is not fully understood. Here, using single cell RNA-seq, we analyze the transcriptome profiles of the various cell types around the scaffold to map the scaffold-induced reaction, in an unbiased approach. This enables mapping of all biomaterial degradation-associated cells at high resolution, revealing distinct subpopulations of tissue-resident macrophages as the major cellular sources of biomaterial degradation in situ. We also find that scaffold architecture can affect the mechanotransduction and catabolic activity of specific material degradation-related macrophage subpopulations in an Itgav-Mapk1-Stat3 dependent manner, eventually leading to differences in scaffold degradation rate in vivo. Our work dissects unanticipated aspects of the cellular and molecular basis of biomaterial degradation at the single-cell level, and provides a conceptual framework for developing functional tissue engineering scaffolds in future.

Promoting musculoskeletal system soft tissue regeneration by biomaterial-mediated modulation of macrophage polarization.

Musculoskeletal disorders are common in clinical practice. Repairing critical-sized defects in musculoskeletal systems remains a challenge for researchers and surgeons, requiring the application of tissue engineering biomaterials. Successful application depends on the response of the host tissue to the biomaterial and specific healing process of each anatomical structure. The commonly-held view is that biomaterials should be biocompatible to minimize local host immune response. However, a growing number of studies have shown that active modulation of the immune cells, particularly macrophages, via biomaterials is an effective way to control immune response and promote tissue regeneration as well as biomaterial integration. Therefore, we critically review the role of macrophages in the repair of injured musculoskeletal system soft tissues, which have relatively poor regenerative capacities, as well as discuss further enhancement of target tissue regeneration via modulation of macrophage polarization by biomaterial-mediated immunomodulation (biomaterial properties and delivery systems). This active regulation approach rather than passive-evade strategy maximizes the potential of biomaterials to promote musculoskeletal system soft tissue regeneration and provides alternative therapeutic options for repairing critical-sized defects.

An Off-the-Shelf Tissue Engineered Cartilage Composed of Optimally Sized Pellets of Cartilage Progenitor/Stem Cells.

Articular cartilage focal lesion remains an intractable challenge in sports medicine, and autologous chondrocytes' implantation (ACI) is one of the most commonly utilized treatment modality for this ailment. However, the current ACI technique requires two surgical steps which increases patients' morbidity and incurs additional medical costs. In the present study, we developed a one-step cryopreserved off-the-shelf ACI tissue-engineered (TE) cartilage by seeding pellets of spheroidal cartilage stem/progenitor cells (CSPCs) on a silk scaffold. The pellets were developed through a hanging-drop method, and the incubation time of 1 day could efficiently produce spheroidal pellets without any adverse influence on the cell activity. The pellet size was also optimized. Under chondrogenic induction, pellets consisting of 40 000 CSPCs were found to exhibit the most abundant cartilage matrix deposition and the highest mRNA expression levels of SOX9, aggrecan, and COL2A1, as compared with pellets consisting of 10 000, 100 000, or 200 000 CSPCs. Scaffolds seeded with CSPCs pellets containing 40 000 cells could be preserved in liquid nitrogen with the viability, migration, and chondrogenic ability remaining unaffected for as long as 3 months. When implanted in a rat trochlear cartilage defect model for 3 months, the ready-to-use, cryopreserved TE cartilage yielded fully cartilage reconstruction, which was comparable with the uncryopreserved control. Hence, our study provided preliminary data that our off-the-shell TE cartilage with optimally sized CSPCs pellets seeded within silk scaffolds exhibited strong cartilage repair capacity, which provided a convenient and promising one-step surgical approach to ACI.

Cranial ultrasonographic screening findings among healthy neonates and their association with neurodevelopmental outcomes.

BACKGROUND: To analyze the findings of cranial ultrasonographic screening in asymptomatic neonates and to assess the association between abnormal results and neurodevelopment. METHODS: We retrospectively reviewed the cranial ultrasonographic screening results of healthy neonates born between 35 and 42 weeks gestation at our hospital from October 2011 to October 2018. RESULTS: In total, 11,681 neonates underwent cranial ultrasonographic screening during the study period, and 9666 (82.7%) had normal results. Of 2015 neonates with abnormal findings, 294 had more than two abnormalities. The most common minor findings were subependymal cysts (8.99%), choroid plexus cysts (2.43%), lenticulostriate vasculopathy (2.34%), frontal horn cysts (1.80%), and enlarged cisterna magna (1.04%). Then, 33 (0.28%) neonates had major abnormalities, including cerebral hemorrhage, periventricular heterotopia, focal cortical dysplasia, anomalies of the corpus callosum, and vascular malformation. Of 1334 neonates who underwent serial clinical evaluations, 76 (5.69%) had neurodevelopmental disorders, including developmental delay, attention-deficit/hyperactivity disorder, and autistic spectrum disorder. CONCLUSION: The incidence rate of intracranial anomalies in healthy neonates was 17.3%, and about 5.69% had neurodevelopmental disorders. Cranial ultrasonographic screening has its own value in helping early detection of intracranial anomalies in healthy neonates, some of which have prognostic implications.

Geographical distribution of hyperuricemia in mainland China: a comprehensive systematic review and meta-analysis.

BACKGROUND: Fructose plays an important role in the complex metabolism of uric acid in the human body. However, high blood uric acid concentration, known as hyperuricemia, is the main risk factor for development of gout. Therefore, we conducted an updated meta-analysis on the prevalence and geographical distribution of hyperuricemia among the general population in mainland China using systematic literature search. METHODS: Five electronic databases were used to search for relevant articles published until 2019. All calculations were conducted using the Comprehensive Meta-Analysis (CMA) software. We included 108 eligible articles (172 studies by sex, 95 studies by regions, and 107 studies by study type) and an overall sample size of > 808,505 participants. RESULTS: The pooled prevalence of hyperuricemia among the general population in mainland China was 17.4% (95% CI: 15.8-19.1%). Our subgroup analysis indicated that the pooled prevalence by regions ranged from 15.5 to 24.6%. Those living Northeast region and being males had the highest prevalence (P < 0.001). In addition, some provinces in South Central, East and Northeast regions reported a high prevalence (> 20%), particularly in males. An increasing prevalence was reported since 2005-2009 until 2015-2019. No publication of bias was observed as indicated by a symmetrical funnel plot and Begg and Mazumdar rank correlation (P = 0.392). CONCLUSION: Prevalence of hyperuricemia is increasing in China, and future studies should investigate the association between the prevalence of hyperuricemia and its risk factors in order to tackle the issue, particularly among the vulnerable groups. Also, our study was the first comprehensive study to investigate the overall prevalence of hyperuricemia in mainland China covering the six different regions.

Is the Yale Global Tic Severity Scale a valid tool for parent-reported assessment in the paediatric population? A prospective observational study in Taiwan.

OBJECTIVE: The Yale Global Tic Severity Scale (YGTSS) is the most commonly used clinician-rated evaluation tool for Tourette syndrome (TS), with established reliability and validity. This study aims to determine whether the YGTSS is a valid parent-reported assessment in the TS population. DESIGN: A prospective cohort study. SETTING: A major medical centre in Taiwan. METHODS: A total of 594 patients were enrolled. A revised traditional Chinese version of the YGTSS was made available to parents via Google docs. Parents were encouraged to complete the YGTSS the day before each outpatient clinic visit. At each visit, a paediatric neurology fellow also administered the YGTSS assessment. We investigated whether differences in scores between physicians and parents changed as the number of parent evaluations increased. The results of the physician assessments were also taken as the expert standard for evaluating the sensitivity and specificity of the parent-reported assessments was conducted for the same visit. RESULTS: The differences in the YGTSS scores between participants and physicians were small. The mean difference in the total assessment score was 4.15 points. As the number of times the parent evaluation was performed increased, the difference between the parent and physician scores decreased. Discrimination of moderate-to-severe attacks was good using the parent-assessed YGTSS (area under the receiver operating characteristic curve, 0.858; 95% CI 0.839 to 0.876). The sensitivity for detecting a moderate-to-severe attack by YGTSS parent assessment was 79.7% (95% CI 76.6 to 82.8), and the specificity was 91.8% (95% CI 89.9 to 93.7). CONCLUSION: The parent-reported YGTSS is a promising tool for TS assessment, demonstrating good discriminative ability for disease severity, with user precision increasing with experience.

Targeted pathological collagen delivery of sustained-release rapamycin to prevent heterotopic ossification.

Heterotopic ossification (HO) in connective tissues like tendons and ligaments severely damages tissue structure. The pathogenesis of HO remains unclear but may involve mTOR. The results presented here indicate that tendon stem/progenitor cells do not undergo osteochondrogenic differentiation when mTOR signaling is inactivated by gene knockout or rapamycin (RAPA) treatment. Meanwhile, it is necessary to deliver RAPA to the injured sites and avoid disturbing the normal tendon. A RAPA delivery system, developed using collagen hybrid peptide (CHP) to modify the surface of poly(lactic-co-glycolic acid) (PLGA) nanoparticles, targeted RAPA specifically to pathological tendon collagen. The CHP-PLGA-RAPA nanoparticles showed excellent pathological collagen affinity, sustained-release ability, and bioactivity. In a mouse model of tendon HO, CHP-PLGA-RAPA nanoparticles specifically bound to pathological tendon and strongly suppressed HO progression. The mTOR signaling pathway appears to be a viable therapeutic target for tendon HO, and CHP-PLGA nanoparticles may be valuable for the treatment of tendon-related diseases.

Automated Video Behavior Recognition of Pigs Using Two-Stream Convolutional Networks.

The detection of pig behavior helps detect abnormal conditions such as diseases and dangerous movements in a timely and effective manner, which plays an important role in ensuring the health and well-being of pigs. Monitoring pig behavior by staff is time consuming, subjective, and impractical. Therefore, there is an urgent need to implement methods for identifying pig behavior automatically. In recent years, deep learning has been gradually applied to the study of pig behavior recognition. Existing studies judge the behavior of the pig only based on the posture of the pig in a still image frame, without considering the motion information of the behavior. However, optical flow can well reflect the motion information. Thus, this study took image frames and optical flow from videos as two-stream input objects to fully extract the temporal and spatial behavioral characteristics. Two-stream convolutional network models based on deep learning were proposed, including inflated 3D convnet (I3D) and temporal segment networks (TSN) whose feature extraction network is Residual Network (ResNet) or the Inception architecture (e.g., Inception with Batch Normalization (BN-Inception), InceptionV3, InceptionV4, or InceptionResNetV2) to achieve pig behavior recognition. A standard pig video behavior dataset that included 1000 videos of feeding, lying, walking, scratching and mounting from five kinds of different behavioral actions of pigs under natural conditions was created. The dataset was used to train and test the proposed models, and a series of comparative experiments were conducted. The experimental results showed that the TSN model whose feature extraction network was ResNet101 was able to recognize pig feeding, lying, walking, scratching, and mounting behaviors with a higher average of 98.99%, and the average recognition time of each video was 0.3163 s. The TSN model (ResNet101) is superior to the other models in solving the task of pig behavior recognition.

Application of Sonography in the Diagnosis and Follow-Up of Trapped Temporal Horn of Lateral Ventricle: Two Case Reports.

Trapped temporal horn of lateral ventricle (TTHLV) is a rare condition of isolated focal hydrocephalus. We report two cases with different presentations, etiologies, and surgical managements. The first case involved an extremely preterm male baby with a history of ventriculitis and intraventricular hemorrhage; he received external ventricle drainage twice due to obstructive hydrocephalus. TTHLV was detected by sonography. He received a ventriculoperitoneal shunt involving two catheters to bypass the adhesion site. There was no ventricular dilatation during 2 years of follow-up. The second case involved a term baby with an enlarged head; brain sonography revealed left focal hydrocephalus with TTHLV and mild midline shift. Neuroendoscopic cystoventriculostomy with fenestration from the left trigone to the frontal horn was performed and serial follow-up brain sonography for 3 months showed decreased ventricle size. The suitable surgical techniques for the management of TTHLV should be adjusted according to the patients' condition to obtain more favorable outcomes. Brain sonography can be a useful tool for the diagnosis and for following up the surgical outcomes in infants with TTHLV.

Characterization and Comparison of Postnatal Rat Meniscus Stem Cells at Different Developmental Stages.

Meniscus-derived stem cells (MeSCs) are a potential cell source for meniscus tissue engineering. The stark morphological and structural changes of meniscus tissue during development indicate the complexity of MeSCs at different tissue regions and stages of development. In this study, we characterized and compared postnatal rat meniscus tissue and MeSCs at different tissue regions and stages of development. We observed that the rat meniscus tissue exhibited marked changes in tissue morphology during development, with day 7 being the most representative time point of different developmental stages. All rat MeSCs displayed typical stem cell characteristics. Rat MeSCs derived from day 7 inner meniscus tissue exhibited the highest self-renewal capacity, cell proliferation, differentiation potential toward various mesenchymal lineage and the highest expression levels of chondrogenic genes and proteins. Transplantation of rat MeSCs derived from day 7 inner meniscus tissue promoted neo-tissue formation and effectively protected joint surface cartilage in vivo. Our results demonstrated for the first time that rat MeSCs are not necessarily better at earlier developmental stages, and that rat MeSCs derived from day 7 inner meniscus tissue may be a superior cell source for effective meniscus regeneration and articular cartilage protection. This information could make a significant contribution to human meniscus tissue engineering in the future. Stem Cells Translational Medicine 2019;8:1318&1329.

Controlled-release curcumin attenuates progression of tendon ectopic calcification by regulating the differentiation of tendon stem/progenitor cells.

Tendon calcification is a common but intractable problem leading to pain and activity limitation when injury or tendinopathy progresses into the late stage. This is because tendon stem/progenitor cells (TSPCs) can undergo aberrant osteogenic differentiation under inflammatory conditions. This study aims to investigate the effect of curcumin, a natural anti-inflammatory agent, on regulating the differentiation of TSPCs in tendon calcification. With inflammatory stimulation, TSPCs showed higher alkaline phosphatase activity and more frequent formation of mineralized nodules which were verified in the culture system; however, curcumin significantly alleviated these pathological changes. In in vivo function analysis, chitosan microsphere-encapsulated curcumin was delivered to injured sites of rat tendon ectopic calcification model. The inflammation in the tendon tissues of the curcumin group was significantly relieved. Controlled-release curcumin partially rescued tendon calcification and enhanced tendon regeneration in animal model. This study demonstrates that controlled-release curcumin can manipulate the fate decision of TSPCs, and that it promotes the tenogenesis and inhibits the osteogenesis of TSPCs in a pathological microenvironment, which provides a possible new therapeutic strategy for tendon disease.

The Plasticity of Mesenchymal Stem Cells in Regulating Surface HLA-I.

A low surface expression level of human leukocyte antigen class I (HLA-I) ensures that the mesenchymal stem cells (MSCs) escape from the allogeneic recipients' immunological surveillance. Here, we discovered that both transcriptional and synthesis levels of HLA-I in MSCs increased continuously after interferon (IFN)-γ treatment, whereas interestingly, their surface HLA-I expression was downregulated after reaching an HLA-I surface expression peak. Microarray data indicated that the post-transcriptional process plays an important role in the downregulation of surface HLA-I. Further studies identified that IFN-γ-treated MSCs accelerated HLA-I endocytosis through a clathrin-independent dynamin-dependent endocytosis pathway. Furthermore, cells that have self-downregulated surface HLA-I expression elicit a weaker immune response than they previously could. Thus uncovering the plasticity of MSCs in the regulation of HLA-I surface expression would reveal insights into the membrane transportation events leading to the maintenance of low surface HLA-I expression, providing more evidence for selecting and optimizing low-immunogenic MSCs to improve the therapeutic efficiency.