A radiomics nomogram based on MSCT and clinical factors can stratify fibrosis in inflammatory bowel disease.

Intestinal fibrosis is one of the major complications of inflammatory bowel disease (IBD) and a pathological process that significantly impacts patient prognosis and treatment selection. Although current imaging assessment and clinical markers are widely used for the diagnosis and stratification of fibrosis, these methods suffer from subjectivity and limitations. In this study, we aim to develop a radiomics diagnostic model based on multi-slice computed tomography (MSCT) and clinical factors. MSCT images and relevant clinical data were collected from 218 IBD patients, and a large number of quantitative image features were extracted. Using these features, we constructed a radiomics model and transformed it into a user-friendly diagnostic nomogram. A nomogram was developed to predict fibrosis in IBD by integrating multiple factors. The nomogram exhibited favorable discriminative ability, with an AUC of 0.865 in the validation sets, surpassing both the logistic regression (LR) model (AUC = 0.821) and the clinical model (AUC = 0.602) in the test set. In the train set, the LR model achieved an AUC of 0.975, while the clinical model had an AUC of 0.735. The nomogram demonstrated superior performance with an AUC of 0.971, suggesting its potential as a valuable tool for predicting fibrosis in IBD and improving clinical decision-making. The radiomics nomogram, incorporating MSCT and clinical factors, demonstrates promise in stratifying fibrosis in IBD. The nomogram outperforms traditional clinical models and offers personalized risk assessment. However, further validation and addressing identified limitations are necessary to enhance its applicability.

Efficacy and Interpretability Analysis of Noninvasive Imaging Based on Computed Tomography in Patients with Hepatocellular Carcinoma After Initial Transarterial Chemoembolization.

RATIONALE AND OBJECTIVES: The objective of this study is to accurately and timely assess the efficacy of patients with hepatocellular carcinoma (HCC) after the initial transarterial chemoembolization (TACE). MATERIALS AND METHODS: This retrospective study consisted of 279 patients with HCC in Center 1, who were split into training and validation cohorts in the ratio of 4:1, and 72 patients in Center 2 as an external testing cohort. Radiomics signatures both in the arterial phase and venous phase of contrast-enhanced computed tomography images were selected by univariate analysis, correlation analysis, and least absolute shrinkage and selection operator regression to build the predicting models. The clinical model and combined model were constructed by independent risk factors after univariate and multivariate logistic regression analysis. The biological interpretability of radiomics signatures correlating transcriptome sequencing data was explored using publicly available data sets. RESULTS: A total of 31 radiomics signatures in the arterial phase and 13 radiomics signatures in the venous phase were selected to construct Radscore_arterial and Radscore_venous, respectively, which were independent risk factors. After constructing the combined model, the area under the receiver operating characteristic curve in three cohorts was 0.865, 0.800, and 0.745, respectively. Through correlation analysis, 11 radiomics signatures in the arterial phase and 4 radiomics signatures in the venous phase were associated with 8 and 5 gene modules, respectively (All P < .05), which enriched some pathways closely related to tumor development and proliferation. CONCLUSION: Noninvasive imaging has considerable value in predicting the efficacy of patients with HCC after initial TACE. The biological interpretability of the radiological signatures can be mapped at the micro level.

A robust and automatic CT-3D ultrasound registration method based on segmentation, context, and edge hybrid metric.

BACKGROUND: The fusion of computed tomography (CT) and ultrasound (US) image can enhance lesion detection ability and improve the success rate of liver interventional radiology. The image-based fusion methods encounter the challenge of registration initialization due to the random scanning pose and limited field of view of US. Existing automatic methods those used vessel geometric information and intensity-based metric are sensitive to parameters and have low success rate. The learning-based methods require a large number of registered datasets for training. PURPOSE: The aim of this study is to provide a fully automatic and robust US-3D CT registration method without registered training data and user-specified parameters assisted by the revolutionary deep learning-based segmentation, which can further be used for preparing training samples for the study of learning-based methods. METHODS: We propose a fully automatic CT-3D US registration method by two improved registration metrics. We propose to use 3D U-Net-based multi-organ segmentation of US and CT to assist the conventional registration. The rigid transform is searched in the space of any paired vessel bifurcation planes where the best transform is decided by a segmentation overlap metric, which is more related to the segmentation precision than Dice coefficient. In nonrigid registration phase, we propose a hybrid context and edge based image similarity metric with a simple mask that can remove most noisy US voxels to guide the B-spline transform registration. We evaluate our method on 42 paired CT-3D US datasets scanned with two different US devices from two hospitals. We compared our methods with other exsiting methods with both quantitative measures of target registration error (TRE) and the Jacobian determinent with paired t-test and qualitative registration imaging results. RESULTS: The results show that our method achieves fully automatic rigid registration TRE of 4.895 mm, deformable registration TRE of 2.995 mm in average, which outperforms state-of-the-art automatic linear methods and nonlinear registration metrics with paired t-test's p value less than 0.05. The proposed overlap metric achieves better results than self similarity description (SSD), edge matching (EM), and block matching (BM) with p values of 1.624E-10, 4.235E-9, and 0.002, respectively. The proposed hybrid edge and context-based metric outperforms context-only, edge-only, and intensity statistics-only-based metrics with p values of 0.023, 3.81E-5, and 1.38E-15, respectively. The 3D US segmentation has achieved mean Dice similarity coefficient (DSC) of 0.799, 0.724, 0.788, and precision of 0.871, 0.769, 0.862 for gallbladder, vessel, and branch vessel, respectively. CONCLUSIONS: The deep learning-based US segmentation can achieve satisfied result to assist robust conventional rigid registration. The Dice similarity coefficient-based metrics, hybrid context, and edge image similarity metric contribute to robust and accurate registration.

MicroRNA-223 negatively regulates the osteogenic differentiation of periodontal ligament derived cells by directly targeting growth factor receptors.

BACKGROUND: MicroRNA (miRNA) is accepted as a critical regulator of cell differentiation. However, whether microRNA-223 (miR-223) could affect the osteogenic differentiation of periodontal ligament (PDL)-derived cells is still unknown. The aim of this study was to explore the mechanisms underlying the roles of miR-223 in the osteogenesis of PDL-derived cells in periodontitis. METHODS: Microarray analysis and real-time polymerase chain reaction (RT-PCR) were used to identify difference in miR-223 expression pattern between healthy and inflamed gingival tissue. The target genes of miR-223 were predicted based on Targetscan and selected for enrichment analyses based on Metascape database. The gain-and loss-of-function experiments were performed to discuss roles of miR-223 and growth factor receptor genes in osteogenic differentiation of PDL-derived cells. The target relationship between miR-223 and growth factor receptor genes was confirmed by a dual luciferase assay. Osteogenic differentiation of PDL-derived cells was assessed by Alizarin red staining, RT-PCR and western blot detection of osteogenic markers, including osteocalcin (OCN), osteopontin (OPN) and runt-related transcription factor 2 (Runx2). RESULTS: MiR-223 was significantly increased in inflamed gingival tissues and down-regulated in PDL-derived cells during osteogenesis. The expression of miR-223 in gingival tissues was positively correlated with the clinical parameters in periodontitis patients. Overexpression of miR-223 markedly inhibited PDL-derived cells osteogenesis, which was evidenced by reduced Alizarin red staining and osteogenic markers expressions. Furthermore, two growth factor receptor genes, including fibroblast growth factor receptor 2 (FGFR2) and transforming growth factor beta receptor 2 (TGFßR2), were revealed to be direct targets of miR-223 and shown to undergo up-regulation in PDL-derived cells during osteogenesis. Moreover, suppression of FGFR2 or TGFßR2 dramatically blocked PDL-derived cells osteogenic differentiation. CONCLUSIONS: Our study provides novel evidence that miR-223 can be induced by periodontitis and acts as a negative regulator of PDL-derived cells osteogenesis by targeting two growth factor receptors (TGFßR2 and FGFR2).

Noninvasive Imaging Evaluation Based on Computed Tomography of the Efficacy of Initial Transarterial Chemoembolization to Predict Outcome in Patients with Hepatocellular Carcinoma.

Purpose: This study aims to develop a new model to more comprehensively and accurately predict the survival of patients with HCC after initial TACE. Patients and Methods: The whole cohort (n = 102) was randomly divided into a training cohort and a validation cohort in the ratio of 8:2. The optimal radiomics signatures were screened using the least absolute shrinkage and selection operator algorithm (LASSO) regression for constructing the radscore to predict overall survival (OS). The C-index (95% confidence interval, CI), calibration curve, and decision curve analysis (DCA) were used to evaluate the performance of the models. The independent risk factors (hazard ratio, HR) for predicting OS were stratified by Kaplan-Meier (K-M) analysis and the Log rank test. Results: The median OS was 439 days (95% CI: 215.795-662.205) in whole cohort, and in the training cohort and validation cohort, the median OS was 552 days (95% CI: 171.172-932.828), 395 days (95% CI: 309.415-480.585), respectively (P = 0.889). After multivariate cox regression, the combined radscore-clinical model was consisted of radscore (HR: 2.065, 95% CI: 1.285-3.316; P = 0.0029) and post-response (HR: 1.880, 95% CI: 1.310-2.697; P = 0.0007), both of which were independent risk factors for the OS. In the validation cohort, the efficacy of both the radscore (C-index: 0.769, 95% CI: 0.496-1.000) and combined model (C-index: 0.770, 95% CI: 0.581-0.806) were higher than that of the clinical model (C-index: 0.655, 95% CI: 0.508-0.802). The calibration curve of the combined model for predicting OS presented good consistency between observations and predictions in both the training cohort and validation cohort. Conclusion: Noninvasive imaging has a good prediction performance of survival after initial TACE in patients with HCC. The combined model consisting of post-response and radscore may be able to better predict outcome.

Near-infrared aggregation-induced emission nanodots for early diagnosis of tongue squamous cell carcinoma and sentinel lymph node mapping.

Fluorescence imaging has been widely used in the biomedical field owing to its merits of high sensitivity, excellent accuracy, high biosafety, etc. However, despite the good performance of fluorescent materials in the diagnosis of subcutaneous tumors or some orthotopic tumors in mice, their potential clinical application for most orthotopic tumors in humans is still limited due to their weak tissue penetration ability and the high thickness of human tissues. Given that the human tongue can extend out of the mouth and is approximately 1 cm thick, the diagnosis of tongue squamous cell carcinoma (TSCC) by fluorescence has great potential for clinical applications. However, to the best of our knowledge, a few studies have been performed to detect tongue tumors using fluorescence imaging, and most of them are administered in a subcutaneous tumor-bearing mouse model and are based on fluorescent materials with aggregation-caused quenching effects. Herein, by developing DPA-TPE-DCM with intense near-infrared fluorescence emission in the aggregation state, aggregation-induced emission materials were used for the first time in the early diagnosis of orthotopic TSCC and sentinel lymph node (SLN) mapping in an immunocompetent mouse model of orthotopic TSCC with a high signal-to-background ratio of 10.2. Moreover, with the guidance of the fluorescence of DPA-TPE-DCM NPs, SLNs smaller than 2 mm in diameter were successfully excised. This study provides new insight and a method for the early diagnosis of TSCC in clinical practice and provides more possibilities to broaden the potential clinical applications of fluorescent materials.

Dual-Energy Computed Tomography Imaging in Early-Stage Hepatocellular Carcinoma: A Preliminary Study.

Background: This study aims to evaluate the application of dual-energy computed tomography (DECT) for multiparameter quantitative measurement in early-stage hepatocellular carcinoma (HCC). Methods: The study retrospectively enrolled 30 patients with early-stage HCC and 43 patients with early-stage HCC who received radiofrequency ablation (RFA) and underwent abdomen enhanced CT scans in GSI mode. The GSI viewer was used for image display and data analysis. The regions of interest (ROIs) were delineated in the arterial phase and the venous phase. The optimal single energy value, CT values on different energy levels (40 keV, 70 keV, 100 keV, and 140 keV), the optimal energy level, the slope of the spectral attenuation curve, the effective atomic number (Z eff), iodine concentration (IC), water concentration (WC), normalized iodine concentration (NIC), and normalized water concentration (NWC) are measured and quantitatively analyzed. Results: The CT values of early-stage HCC at different single energy levels in dual phases were significantly different, and the single energy values were negatively correlated with the CT values. In the arterial phase and the venous phase, the optimal energy values for the best contrast-to-noise ratio were (68.34 ± 3.20) keV and (70.14 ± 2.01) keV, respectively. The slope of the spectral attenuation curve showed a downward trend at 40 keV, 70 keV, 100 keV, and 140 keV, but there was no statistically significant difference (P > 0.05). Z eff was positively correlated with IC and standardized IC, but has no significant correlation with WC and NWC in dual phases. Conclusion: DECT imaging contains multiparameter information and has different application values for early-stage HCC, and it is necessary to select the parameters reasonably for personalized and comprehensive evaluation.

Artificial Intelligent Multi-Modal Point-of-Care System for Predicting Response of Transarterial Chemoembolization in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) ranks the second most lethal tumor globally and is the fourth leading cause of cancer-related death worldwide. Unfortunately, HCC is commonly at intermediate tumor stage or advanced tumor stage, in which only some palliative treatment can be used to offer a limited overall survival. Due to the high heterogeneity of the genetic, molecular, and histological levels, HCC makes the prediction of preoperative transarterial chemoembolization (TACE) efficacy and the development of personalized regimens challenging. In this study, a new multi-modal point-of-care system is employed to predict the response of TACE in HCC by a concept of integrating multi-modal large-scale data of clinical index and computed tomography (CT) images. This multi-modal point-of-care predicting system opens new possibilities for predicting the response of TACE treatment and can help clinicians select the optimal patients with HCC who can benefit from the interventional therapy.

Optimal timing of combining sorafenib with trans-arterial chemoembolization in patients with hepatocellular carcinoma: A meta-analysis.

BACKGROUND: The combination therapy of trans-arterial chemoembolization (TACE) and sorafenib were proved to be one of the effective methods for intermediate and advanced hepatocellular carcinoma (HCC). Although it has been confirmed that the combination therapy can prolong survival for advanced HCC effectively, the therapeutic efficacy and safety are still controversial and the clinical value has not been determined. This meta-analysis aims to evaluate the efficacy and safety of combination therapy and discuss the optimal timing of combination for better clinical benefits. DATA SOURCES: PubMed, EMBASE, the Cochrane Library, MEDLINE, and Web of Science were systematically reviewed to search for relevant studies published before May 15, 2021. Studies comparing the efficacy and safety of TACE + sorafenib with TACE + placebo / alone were adopted. Two reviewers independently extracted study outcomes. The data were analyzed through fixed/random-effect meta-analysis models with Review Manager (Version 5. 3) software. RESULTS: 7 randomized controlled trials (RCTs) were included with 1464 patients with unresectable HCC (734 in TACE + sorafenib group and 730 in TACE + placebo or alone group). Meta-analysis showed that objective response rate (ORR) and disease control rate (DCR) were slightly improved in TACE + sorafenib group (ORR: risk ratio = 1.24; 95% confidence interval: 1.08-1.42; P = 0.002; DCR: risk ratio = 1.09; 95% confidence interval: 1.01-1.18; P = 0.02). The combination therapy obviously improved time to progression (TTP) (hazard ratio: 0.73; 95% confidence interval: 0.55-0.96; P = 0.03) and progression-free survival (PFS) (hazard ratio 0.62; 95% confidence interval: 0.52-0.73, P < 0.00001) but not overall survival (OS) (hazard ratio: 0.93; 95% confidence interval: 0.59-1.46; P = 0.75) or time to untreatable progression (TTUP) (hazard ratio: 0.76; 95% confidence interval: 0.31-1.89; P = 0.56). In addition, the incidence of adverse reactions (AEs) in combination group were higher than TACE + placebo / alone group. Furthermore, the subgroup analysis showed that the heterogeneity of TTP was notably decreased (pre-TACE: P = 0.12, I2 = 48%; post-TACE: P = 0.58, I2 = 0%), and the hazard ratio was 0.59 (95% confidence interval: 0.51-0.68; P < 0.00001) in pre-TACE subgroup which indicated that combination before TACE significantly prolonged TTP but not in combination after TACE (hazard ratio: 0.88; 95% confidence interval: 0.62-1.24; P = 0.46). In term of AEs, sensitivity analysis indicated that the risk ratio for hand-foot skin reaction, diarrhea, rash/desquamation, and hypertension was 7.41, 2.58, 2.14, 1.55 in pre-TACE subgroup respectively and was 11.34, 3.26, 3.61, 4.11 in post-TACE subgroup respectively (All P < 0.05). CONCLUSION: The combination of TACE and sorafenib significantly can improve TTP and PFS, and reduce the level of risk of adverse reactions of unresectable HCC, especially in the combination before TACE.

Optimal timing for hospice-shared care initiation in terminal cancer patients.

PURPOSE: The existing concept suggests early palliative and hospice therapy for a better quality of care (QOC) and less medical expense in terminal cancer patients, but the time points of "early" initiation were defined by pre-set study protocol rather than the real-world data. The study aimed to determine the optimal timing of initiating palliative care for patients with terminal cancer. METHODS: This retrospective population-based study was conducted using a nationwide database. We extracted patients with cancer who were in their last year of lives in the period from 1 January 2010 to 31 December 2013 and categorized them into two groups ("hospice-shared care" (HSC) group and "usual care" (UC) group) after a matching process. Subsequently, we used a generalized linear mixed-effects model to compare the QOC and medical expenses between groups. RESULTS: After the selection and matching process, we enrolled 1714 patients (67.7 ± 13.2 years, 62.7% male) categorized into the HSC and UC groups (n = 857 in each group). The HSC groups showed generally better QOC in the four indices (with emergency room visit, hospitalization, intensive care unit admission, and receiving chemotherapy) than the UC group in those who initiated HSC 8-60 days before death. The HSC group also had significantly lower medical expenses than the UC group in those who initiated HSC 15-90 days before death. CONCLUSIONS: Among patients with terminal cancer, HSC initiation before the last 8 days and 15 days of lives can effectively improve QOC and save medical expenses, respectively.

Imaging Tool for Predicting Renal Clear Cell Carcinoma Fuhrman Grade: Comparing R.E.N.A.L. Nephrometry Score and CT Texture Analysis.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most common renal malignant tumor. Preoperative imaging boasts advantages in diagnosing and choosing treatment methods for ccRCC. PURPOSE: This study is aimed at building models based on R.E.N.A.L. nephrometry score (RNS) and CT texture analysis (CTTA) to estimate the Fuhrman grade of ccRCC and comparing the advantages and disadvantages of the two models. MATERIALS AND METHODS: 143 patients with pathologically confirmed ccRCC were enrolled. All patients were stratified into Fuhrman low-grade and high-grade groups with complete CT data and R.E.N.A.L. nephrometry scores. CTTA features were extracted from the ROI delineated at the largest tumor level, and RNS and CTTA features were included in the logistic regression model, respectively. RESULTS: RNS model constructed based on multivariate logistic regression analysis showed that 3 pts for R-scores, 2 pts for E-scores, and 3 pts for L-scores were significant indicators to predict high-grade ccRCC, the AUC of RNS model was 0.911, and the sensitivity and specificity were 71.11% and 83.67%, respectively. The CTTA-model confirmed energy, kurtosis, and entropy as independent predictive factors, and the AUC of CTTA model was 0.941, with an optimal sensitivity and specificity of 84.44% and 93.88%. CONCLUSIONS: R.E.N.A.L. nephrometry score has a certain provocative effect on the Fuhrman pathological grading of ccRCC. As a potential emerging technology, CTTA is expected to replace R.E.N.A.L. nephrometry score in evaluating patients' Fuhrman classification, and this approach might become an available method for assisting clinicians in choosing appropriate operation.

Epidemiology survey of dental fluorosis in rural area of Tianjin city / 口腔疾病防治

Objective@#To investigate the situation of dental fluorosis and residents awareness of dental flourosis in rural area of Tianjin, providing the basis for control of dental fluorosis prevalence level and continuous supervise of dental fluorosis prevalence.@*Methods@#The objectives were selected by stratified cluster sampling method. Health interview survey and oral examination were perfor med. @*Results @#The prevalence of dental fluorosis was 5.2% in 3-5 years children group, 68.6% in 12-14 years youth group, 64.5% in 15 years youth group, and 68.2% in 35-74 years group. The prevalence of dental fluorosis in 12-14 years group was lower than that in 2005 (χ2=21.62, P < 0.001). The community index of dental fluorosis (CFI ) was 0.1 in 3-5 years children group, 1.48 in 12-15 years youth group, 1.85 in 35-74 years old group. 47.7% students knew nothing about dental fluorosis, and 54.2% adult dental fluorosis patients did not know they were suffering from dental fluorosis. 47.4% of the subjects knew the relationship between dental fluorosis and fluoride in drinking water, and 18.8% subjects considered dental fluorosis was related with tooth cleaning. @*Conclusion @#The prevalence of dental fluorosis in 12-14 years old students was lower than 12 years old at 2005, but the increase of prevalence of dental fluorosis in 3-5 years children indicates the intake of fluorosis should be more strictly controlled. The awareness of dental fluorosis in rural area residents is poor and oral health education about fluorosis should be enhanced.

A Cavity Preparation Evaluation System in the Skill Assessment of Dental Students.

The aim of this study was to compare a computerized, laser-scanning Cavity Preparation Skill Evaluation System (CPSES) with conventional teachers' eye-hand grading assessment of dental students' Class I cavity preparation evaluations. Thirty-eight cavity preparations of lower left first molars made by junior dental students at a dental school in China were tested from September 2013 to November 2014. The outline and retention form, smoothness, depth, wall angulation, and cavity margin index of the preparations were evaluated by CPSES and then by teachers' eye-hand grading. The mean difference in scores for each method was considered, as was the variability of scores within each method. Compared with the teachers' eye-hand grading method, CPSES provided objective evaluation results that had statistically significant differences (p<0.05). A questionnaire was also designed and distributed to the students; the response rate was 100%. The results indicated that most of the students recognized CPSES effects in the preclinical teaching; 92.1% perceived that CPSES provided high simulation and appropriate practice guidance for them; and 94.7% reported that the evaluation results provided by CPSES gave targeted and objective recommendations. These findings suggest that CPSES can consistently and reliably scan a student's tooth preparation, compare it to a theoretically ideal preparation, and provide objective feedback. The application of CPSES in preclinical operative training can help students better understand the desired parameters for occlusal cavity preparation skills and encourage students in their self-paced learning and independent practice.

[Myocardial regeneration was promoted by injected Oct4 adenovirus eukaryotic expression vector].

OBJECTIVE: To construct octamer-binding transcription factor-4 (Oct4) adenoviruse eukaryotic expression vector pAV.Ex1d.-CMV>mOCT4/IRES/eGFP, and study its effect on myocardial regeneration in mice. METHODS: We constructed eukaryotic expression vector pAV.Ex1d.-CMV>mOCT4/IRES/eGFP using Gateway(R);technology and then packaged the vector with adenoviruses. After adenovirus packaging, the vector was injected into the mouse myocardium by microsyringe. The expression of Oct4 was determined by the methods of immunofluorescence and RT-PCR, and hematoxylin-eosin (HE) staining was used to detect whether the myocardial tissue was changed after the expression of Oct4. We also constructed mouse myocardial infarction model and identified the infarct area using HE staining for injecting the Oct4 adenovirus vector into the area surrounding the infarct area, Four weeks later, we detected the expression of cardiac troponin T in the infact area by Western blotting. RESULTS: Immunofluorescence showed red fluorescence indicating that Oct4 was expressed in the myocardial cell nucleus, but it could not be detected in the control group and the the control virus group. RT-PCR also proved the expression of Oct4 in Oct4 adenovirus vector group but not in the control virus group and the control group. There was no pathological changes in the myocardial tissues after Oct4 was expressed in vivo. Four weeks after the adenovirus vector was injected around the infarct area, the expression level of cardiac troponin T in Oct4 group was significantly different from that in the control group or the control empty virus group (P<0.5). CONCLUSION: Exogenous Oct4 can be expressed in the mature myocardial tissues in vivo and promote myocardial regeneration.

[Effect of pulsed electrical stimulation on the proliferation and differentiation of H9c2 cells].

OBJECTIVE: To observe the inhibition of pulsed electric stimulation on the proliferation of H9c2 cells and the induction on the differentiation of the cells. METHODS: We applied a set of pulse electrical stimulations of different frequencies (0, 1, 5, 10, 50, 100 Hz), different voltage (0, 5, 10, 20, 40, 50 V) and different time (0, 1, 2, 4, 6, 8 h/d) on H9c2 cells in rats. 5-azacytidine was used as an intervention factor control. We detected the proliferation rate of H9c2 cells through MTT assay, the expressions of cardiac troponin T (cTNT) and Oct4 through immunofluorescence cytochemical staining, and the expressions of cTNT and α-MHC mRNA using RT-PCR method. RESULTS: Pulsed electric stimulation inhibited the proliferation of H9c2 cells (P<0.05). The pulsed electric stimulation of 1 Hz, 4 h/d and 10 V was proved optimized in inhibiting the growth of H9c2 cells to the greatest extent but not inducing the death of cells. Two weeks after the optimized pulsed elctric stimulation on H9c2 cells, the expression of Oct4 was reduced (P<0.05), while the expressions of cTNT and α-MHC were still strong. CONCLUSION: Pulsed electric stimulation can not only inhibit the reproduction of myoblast cell line H9c2 in heart tissue of rat embryo, but also induce the differentiation of H9c2 cells. During it, the expressions of cTNT and α-MHC are enhanced but Oct4 is weakened.

[Effect of electrical stimulation on the differentiation of induced pluripotent stem cells into cardiomyocytes induced by vitamin C in vitro].

OBJECTIVE: To investigate the effect of electrical stimulation on the differentiation of induced pluripotent stem cells (iPSCs) into cardiomyocytes in vitro. METHODS: Classical hanging-drop method was used to induce iPSCs from mice to form embryoid bodies (EBs) and vitamin C was contained in the medium through the induction period. According to whether or not electrical stimulation was used in the whole induction period, iPSCs were divided to electrical stimulation group and non-stimulation group. During the induction, dynamic morphological changes of the EBs were observed and photographed, the time point when beating EBs in each group appeared was recorded and the number of them was counted. The percentage of beating ones in all EBs was calculated as the differentiation rate of cardiomyocytes induced from iPSCs. Furthermore, expression of cardiac troponin T (cTnT) was observed by immunofluorescent staining under a confocal laser scanning microscope (CLSM), and mRNA expression levels of the related genes Oct-4, GATA-4 and α-MHC were analyzed by RT-PCR. RESULTS: Compared with the non-stimulation group, beating cells in electrical stimulation group appeared in a shorter time, and the differentiation rate of cardiomyocytes was higher [(68.89 ± 5.09)% vs (52.22 ± 3.85)%, P<0.05]. c-TnT was expressed in the beating area of both groups, but the cells in the electrical stimulation group showed a more clear cytoskeleton. The mRNA level of Oct-4 decreased in a time-dependent manner in the whole period of induction and in the electrical stimulated group it decreased faster than the non-stimulation group (P<0.05). In addition, more GATA4 and α-MHC mRNA in electrical stimulation group were expressed than the non-stimulated group at the same point-in-time (P<0.05). CONCLUSION: The electrical stimulation which simulates cardiac electrical microenvironment to some extent improved the differentiation of iPSCs into functional cardiomyocytes induced by vitamin C in vitro.