Multimodality imaging for the diagnosis of left ventricular apical hypoplasia: A case presentation and review of the literatures.

Left ventricular apical hypoplasia is a rare malformation recently described congenital abnormality characterized by: (1) truncation of the left ventricle, with the septum projecting toward the right ventricle; (2) abnormal papillary muscle originating from the flattened left ventricular apex; (3) a narrow right ventricle encompassing the periapical area of the left ventricle; (4) fatty infiltration of the apex of the left ventricle. We reported a case of LVAH and reviewed the patient's clinical presentation. And its morphologic characteristics were revealed by multimodality imaging, including echocardiography and cardiac magnetic resonance imaging. Additionally, we reviewed 41 cases from 32 reports to summarize the pathogenesis and analyzed the imaging manifestations of LVAH in this study, aiming to provide new ideas for the diagnosis and clinical management of LVAH patients.

VGLL4 promotes vascular endothelium specification via TEAD1 in the vascular organoids and human pluripotent stem cells-derived endothelium model.

BACKGROUND: We have shown that Hippo-YAP signaling pathway plays an important role in endothelial cell differentiation. Vestigial-like family member 4 (VGLL4) has been identified as a YAP inhibitor. However, the exact function of VGLL4 in vascular endothelial cell development remains unclear. In this study, we investigated the role of VGLL4, in human endothelial lineage specification both in 3D vascular organoid and 2D endothelial cell differentiation. METHODS AND RESULTS: In this study, we found that VGLL4 was increased during 3D vascular organoids generation and directed differentiation of human embryonic stem cells H1 towards the endothelial lineage. Using inducible ectopic expression of VGLL4 based on the piggyBac system, we proved that overexpression of VGLL4 in H1 promoted vascular organoids generation and endothelial cells differentiation. In contrast, VGLL4 knockdown (heterozygous knockout) of H1 exhibited inhibitory effects. Using bioinformatics analysis and protein immunoprecipitation, we further found that VGLL4 binds to TEAD1 and facilitates the expression of endothelial master transcription factors, including FLI1, to promote endothelial lineage specification. Moreover, TEAD1 overexpression rescued VGLL4 knockdown-mediated negative effects. CONCLUSIONS: In summary, VGLL4 promotes EC lineage specification both in 3D vascular organoid and 2D EC differentiation from pluripotent stem cell, VGLL4 interacts with TEAD1 and facilitates EC key transcription factor, including FLI1, to enhance EC lineage specification.

VGLL4-TEAD1 promotes vascular smooth muscle cell differentiation from human pluripotent stem cells via TET2.

The Hippo signaling pathway plays a critical role in cardiovascular development and stem cell differentiation. Using microarray profiling, we found that the Hippo pathway components vestigial-like family member 4 (VGLL4) and TEA domain transcription factor 1 (TEAD1) were upregulated during vascular smooth muscle cell (VSMC) differentiation from H1 ESCs (H1 embryonic stem cells). To further explore the role and molecular mechanisms of VGLL4 in regulating VSMC differentiation, we generated a VGLL4-knockdown H1 ESC line (heterozygous knockout) using the CRISPR/Cas9 system and found that VGLL4 knockdown inhibited VSMC specification. In contrast, overexpression of VGLL4 using the PiggyBac transposon system facilitated VSMC differentiation. We confirmed that this effect was mediated via TEAD1 and VGLL4 interaction. In addition, bioinformatics analysis revealed that Ten-eleven-translocation 2 (TET2), a DNA dioxygenase, is a target of TEAD1, and a luciferase assay further verified that TET2 is the target of the VGLL4-TEAD1 complex. Indeed, TET2 overexpression promoted VSMC marker gene expression and countered the VGLL4 knockdown-mediated inhibitory effects on VSMC differentiation. In summary, we revealed a novel role of VGLL4 in promoting VSMC differentiation from hESCs and identified TET2 as a new target of the VGLL4-TEAD1 complex, which may demethylate VSMC marker genes and facilitate VSMC differentiation. This study provides new insights into the VGLL4-TEAD1-TET2 axis in VSMC differentiation and vascular development.

Association between preoperative on-site CCU visits and postoperative delirium in patients undergoing cardiac surgery: A retrospective cohort study.

BACKGROUND: Postoperative delirium (POD) is a common complication after cardiac surgery (CS), with symptoms like attention disorders and even delays patients' recovery. AIMS: To evaluate the impact of preoperative on-site visits in the cardiac care unit (CCU) on POD after CS. STUDY DESIGN: Patients admitted to the CCU with extracorporeal CS were included in the visiting or non-visiting group according to whether they were on visiting week. The visiting group received a preoperative visit from a nurse-led multidisciplinary visiting team (including CCU nurses and physicians) 1 week before surgery in addition to standard care. The non-visiting group received standard care like unstructured information from the CS team and anesthesiologists and so on. The Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) were used to evaluate the POD severity. The incidence, occurrence and duration of POD, as well as the CCU length of stay, postoperative mechanical ventilation duration and length of hospital stay were compared between the two groups. RESULTS: A total of 735 participants (369 in the visited group and 366 in the unvisited group) were included in this study. Preoperative on-site visits were associated with a decreased POD incidence (odds ratio [OR]: 0.524, 95% CI: 0.336-0.817), an improved POD severity (OR: 0.578, 95% CI: 0.359-0.932) and a shortening POD duration (OR: 0.972, 95% CI: 0.951-0.994). There was a significant difference between the visiting and non-visiting groups in the mechanical ventilation duration (OR: 0.987, 95% CI: 0.978-0.996). CONCLUSIONS: Preoperative on-site visits are associated with a reduction in the incidence, duration, and severity of POD, as well as the mechanical ventilation duration of patients. RELEVANCE TO CLINICAL PRACTICE: This study found that preoperative on-site visits were associated with the onset, duration, severity and duration of mechanical ventilation of POD. Although many factors influence the occurrence of POD, a multidisciplinary visiting team led by a nurse (including CCU nurses and physicians) can provide early nursing interventions through preoperative visits, better obtain postoperative cooperation from patients, establish a good nurse-patient relationship and provide better health services to patients. In a realistic CCU setting, nurses and physicians can act as educators, assessing patients before surgery, enhancing preoperative education, improving patient familiarity with the CCU environment and teaching sign language communication skills when patients are mechanically ventilated. These findings can therefore provide the basis for effective clinical care to prevent postoperative POD.

YAP inhibition promotes endothelial cell differentiation from pluripotent stem cell through EC master transcription factor FLI1.

Endothelial cells (ECs) derived from pluripotent stem cells (PSCs) provide great resource for vascular disease modeling and cell-based regeneration therapy. However, the molecular mechanisms of EC differentiation are not completely understood. In this study, we checked transcriptional profile by microarray and found Hippo pathway is changed and the activity of YAP decreased during mesoderm-mediated EC differentiation from human embryonic stem cells (hESCs). Knockdown of YAP in hESCs promoted both mesoderm and EC differentiation indicating by mesodermal- or EC-specific marker gene expression increased both in mRNA and protein level. In contrast, overexpression of YAP inhibited mesoderm and EC differentiation. Microarray data showed that several key transcription factors of EC differentiation, such as FLI1, ERG, SOX17 are upregulated. Interestingly, knockdown YAP enhanced the expression of these master transcription factors. Bioinformation analysis revealed that TEAD, a YAP binds transcription factors, might regulate the expression of EC master TFs, including FLI1. Luciferase assay confirmed that YAP binds to TEAD1, which would inhibit FLI1 expression. Finally, FLI1 overexpression rescued the effects of YAP overexpression-mediated inhibition of EC differentiation. In conclusion, we revealed the inhibitory effects of YAP on EC differentiation from PSCs, and YAP inhibition might promote expression of master TFs FLI1 for EC commitment through interacting with TEAD1, which might provide an idea for EC differentiation and vascular regeneration via manipulating YAP signaling.

Case report of the first cured patient with Mycobacterium Chimaera infection following cardiac valve replacement in the mainland of China.

BACKGROUND: Mycobacterium chimaera infections subsequent to cardiac surgery are related to contaminated heater-cooler devices, with high mortality. Nevertheless, few studies have been reported in Asia. CASE PRESENTATION: We described the case of a 55-year-old man with Mycobacterium chimaera infection following cardiac surgery in the mainland of China. He was diagnosed with endocarditis caused by Mycobacterium chimaera subsequent to open heart surgery. Metagenomic next-generation sequencing (mNGS) and 16S rRNA gene PCR analysis were used to identify potential pathogens. The patient underwent redo valve replacement surgery and received combination therapy with azithromycin, ethambutol, linezolid, and amikacin. No signs of relapse were observed during the 11-month follow-up visit. CONCLUSIONS: This is the first documented case of Mycobacterium chimaera infection following cardiac surgery in the mainland of China and the first documented transnational imported case worldwide. Moreover, mNGS is a novel diagnostic technology that can guide antimicrobial therapy prior to obtaining fluid/tissue culture results for Mycobacterium chimaera, providing a new approach for the detection of potential Mycobacterium chimaera infection.

Generation of human embryonic stem cell lines (WAe001-A-67,WAe001-A-68) with TEAD1 and TEAD4 expression by the PiggyBac transposon system.

Transcription factors TEAD1 and TEAD4 play an important role in development, differentiation, cell growth and proliferation. To further understand the exact role of TEAD1 and TEAD4 in these processes. We generated TEAD1 and TEAD4 doxycycline-inducible expression human embryonic stem cell lines (WAe001-A-67 and WAe001-A-68) by PiggyBac transposon system. These cell lines retained normal morphology and karyotype, normal expression of pluripotent markers, and differentiation potential. These cell lines can be used to verify whether the TEAD1 and TEAD4 play a role in stem cell and cell lineage differentiation.

Extracellular vesicles derived from myocardial infarction plasma inhibit BMSCs apoptosis and enhance cardiac function via AKT signaling pathway.

This study aimed to investigate whether extracellular vesicles (EVs) secreted in myocardial infarction (MI) plasma could protect against apoptosis of bone marrow mesenchymal stem cells (BMSCs) following hypoxia or serum deprivation in vitro and improve cardiac function following MI in vivo. The plasma samples were taken from female rats 24 h after MI. EVs were obtained and co-cultured with BMSCs. We found that EVs could be taken up by BMSCs. Co-culturing with EVs attenuated hypoxia-induced apoptosis of BMSCs in EVs in a dose-dependent manner, which was reversed by the pharmacological inhibition of AKT signaling. Co-culturing with EVs improved transplantation efficiency and blunted MI-induced apoptosis of BMSCs in vivo. Furthermore, transplantation of BMSCs together with EVs can effectively promote the increase in capillary density both at the border and central zone of myocardium and ameliorate myocardial remodeling in MI rats. BMSCs and EVs transplantation treatment exhibited significant improvements in ejection fraction, fraction shortening, left ventricular end-diastolic dimensions, and left ventricular end-systolic dimensions, as evaluated by echocardiography four weeks after MI in rats. Finally, levels of differentiation- and apoptosis-related microRNAs expression in EVs that may mediate these effects were also identified by microarray and quantitative real-time PCR. In conclusion, the present results suggest a potential role of plasma-derived EVs in decreasing apoptosis of BMSCs by activating AKT signaling, promoting angiogenesis, ameliorating myocardial remodeling, and improving cardiac function in MI rats. EV application may be a novel option to ameliorate the therapeutic efficiency of BMSCs to improve cardiac function following MI.

Establishment and characterization of human induced pluripotent stem cell line (WMUi020-A) from a patient with bicuspid aortic valve aortopathy.

A human induced pluripotent stem cell (hiPSC) line (WMUi020-A) was generated from the aortic smooth muscle cells of a 56-year-old donor with bicuspid aortic valve and ascending aortic aneurysm. Episomal vector-mediated Non-integration iPSC reprogramming was used for this iPSC line generation. The established iPSC line highly expressed pluripotency markers with three germ-layer differentiation potential in vitro, as well as a normal karyotype. We further found that this iPSC line has a potential mutation of ROBO4 (c.161 T>C, p.Q54R), which may be useful for the disease modeling of bicuspid aortic valve aortopathy.

Generation of human induced pluripotent stem cell line (WMUi001-A) from a patient with aortic dissection.

A human induced pluripotent stem cell (hiPSC) line (WMUi001-A) was generated from the aortic tissue of a 47-year-old donor with aortic dissection and normal blood pressure. Integration-free episomal vector-mediated reprogramming was used for the generation of this iPSC line. The established iPSC line was found to express pluripotency markers, exhibit a differentiation potential in vitro, as well as display a normal karyotype. We further identified that this iPSC line contained a mutation in collagen type IV (COL4A2, R131M), which may serve as a useful tool for the disease modeling of aortic dissection.

Generation of a human embryonic stem cell (WAe001-A-47) with hVGLL4 doxycyclin-inducible expression by the PiggyBac transposon system.

VGLL4 is a new component of the Hippo pathway and bind TEADs to compete with YAP, so as to inhibit tumor progression, but its role in stem cell and organ regeneration remains unclear. Using the PiggyBac transposon system, we generated a VGLL4 doxycycline-inducible expression human embryonic stem cell line (WAe001-A-47). The established hESC line retains its normal morphology and pluripotency markers with in vitro differentiation potential, as well as a normal karyotype.

Epigallocatechin-3-gallate (EGCG) inhibits aggregation of pulmonary fibrosis associated mutant surfactant protein A2 via a proteasomal degradation pathway.

BACKGROUND/AIMS: Epigallocatechin-3-gallate (EGCG), a major catechin found in green tea, plays an important anti-tumor role and is involved in various other biological processes, such as, neuroprotection by prevention of aggregation of misfolded proteins generated because of genetic defects. Surfactant protein A2 mutations (G231V and F198S) have been identified to be associated with pulmonary fibrosis and lung cancer, and these mutations cause protein aggregation, instability as well as secretion deficiency. The present study focused on investigating the inhibitory effects of EGCG on aggregation of mutant SP-A2 and elucidating the potential mechanisms underlying this action. METHODS: Wild-type and mutant SP-A2 were transiently expressed in CHO-K1 cells. The aggregated and soluble proteins were separated into NP-40-insoluble and NP-40-soluble fractions. Protein stability was validated by chymotrypsin limited proteolysis assay. Western blot and RT-PCR were used to determine the protein and mRNA expression level, respectively. RESULTS: Mutant SP-A2 alone or wild-type SP-A2 co-expressed with G231V formed NP-40-insoluble aggregates in CHO-K1 cells. EGCG significantly suppressed this aggregation and alleviated mutant SP-A2 accumulation in the ER. When combined with 4-PBA, EGCG treatment completely blocked mutant SP-A2 aggregate formation. Though secretion of mutant protein was not affected, EGCG facilitated protein instability in both wild-type and mutant protein. Importantly, MG132, a proteasome inhibitor, reversed EGCG-induced aggregate reduction. CONCLUSIONS: EGCG inhibits aggregation of misfolded SP-A2 via induction of protein instability and activation of proteasomal pathway for aggregate degradation.

Autotaxin/lysophosphatidic acid signaling mediates obesity-related cardiomyopathy in mice and human subjects.

Obesity is associated with increased cardiovascular morbidity and mortality, but the direct signals to initiate or exaggerate cardiomyopathy remain largely unknown. Present study aims to explore the pathophysiological role of autotaxin/lysophosphatidic acid (LPA) in the process of cardiomyopathy during obesity. Through utilizing mouse model and clinical samples, present study investigates the therapeutic benefits of autotaxin inhibitor and clinical correlation to obesity-related cardiomyopathy. The elevated circulating levels of autotaxin are closely associated with cardiac parameters in mice. Administration with autotaxin inhibitor, PF-8380 effectively attenuates high fat diet-induced cardiac hypertrophy, dysfunction and inflammatory response. Consistently, autotaxin inhibition also decreases circulating LPA levels in obese mice. In in vitro study, LPA directly initiates cell size enlargement and inflammation in neonatal cardiomyocytes. More importantly, circulating levels of autotaxin are positively correlated with cardiac dysfunction and hypertrophy in 55 patients. In conclusion, present study uncovers the correlation between circulating autotaxin and cardiac parameters in mice and human patient, and provided solid evidence of the therapeutic application of autotaxin inhibitor in combating obesity-related cardiomyopathy.

Chemical chaperone 4-phenylbutyric acid alleviates the aggregation of human familial pulmonary fibrosis-related mutant SP-A2 protein in part through effects on GRP78.

G231V and F198S mutations in surfactant protein A2 (SP-A2) are associated with familial pulmonary fibrosis. These mutations cause defects in dimer/trimer assembly, trafficking, and secretion, as well as cause mutant protein aggregation. We investigated the effects and mechanisms of chemical chaperones on the cellular and biochemical properties of mutant SP-A2. Chemical chaperones, including 4-phenyl butyric acid (4-PBA), could enhance secretion and decrease intracellular aggregation of mutant SP-A2 in a dose-dependent manner. Interestingly, increased levels of aggregated mutant SP-A2, resulting from MG-132-mediated proteasome inhibition, could also be alleviated by 4-PBA. 4-PBA treatment reduced the degradation of mutant SP-A2 to chymotrypsin digestion in CHO-K1 cells and up-regulated GRP78 (BiP) expression. Overexpression of GRP78 in SP-A2 G231V- or F198S-expressing cells reduced, whereas shRNA-mediated knockdown of GRP78 enhanced aggregation of mutant SP-A2, suggesting that GRP78 regulates aggregation of mutant SP-A2. Together, these data indicate chemical chaperone 4-PBA and upregulation of GRP78 can alleviate aggregation to stabilize and facilitate secretion of mutant SP-A2. The up-regulation expression of GRP78 might partially contribute to the aggregate-alleviating effect of 4-PBA.

Central zone of myocardial infarction: a neglected target area for heart cell therapy.

The purpose of this study was to investigate the fate of transplanted cells in the central zone of myocardial infarction (MI), and to clarify the relationship between the injection-site impact and the efficacy of cell therapy. MI was created by coronary ligation in female rats. Three weeks later, 3-million labelled male bone marrow mesenchymal stem cells (BMSCs) were directly injected into the border (BZC group) or central zone (CZC group) of MI area. As a control, culture medium was injected into the same sites. Cell survival was evaluated by quantitative real-time polymerase chain reaction, and apoptosis was assayed with TUNEL and caspase-3 staining. Four weeks after transplantation, heart function and cardiac morphometry were evaluated by echocardiography and Masson's Trichrome staining, respectively. Angiogenesis and myogenesis were detected by immunofluorescence staining. After cell transplantation into the border or central zone, there was no cell migration between the different zones of MI. BMSCs in the CZC group exhibited no difference in apoptotic percentage, in the long-term survival, when compared with those in the BZC group. However, they did effectively promote angiogenesis and cellular myogenic differentiation. Although cell delivery in the central zone of MI had no effect on the recovery of heart function compared with the BZC group, the retained BMSCs could still increase the scar thickness, and subsequently exhibit a trend in the reverse remodelling of ventricular dilation. Hence, we concluded that the central zone of MI should not be ignored during cell-based therapy. Multiple site injection (border+central zone) is strongly recommended during the procedure of cell transplantation.

Intravenous administration of bone marrow mesenchymal stromal cells is safe for the lung in a chronic myocardial infarction model.

AIMS: Intravenous administration of bone marrow mesenchymal stromal cells (MSCs) is an attractive option for the treatment of myocardial infarction (MI). Previous studies revealed that MSC infusion could limit the deterioration of cardiac function following acute MI; however, little is known regarding the safety and efficacy of MSC infusion for chronic MI. In this study, we address cell retention after intravenous injection in a chronic MI model, and the fate and impact of distributed MSCs in the lung and heart. METHODS: MI model was created by coronary ligation in female rats. A total of 3 weeks later, 5 × 10(6) bromodeoxyuridine-labeled male MSCs in 300 µl phosphate-buffered solution (PBS) were infused intravenously (cell transplantation group, n = 37). The same volume of PBS was infused and served as the control group (n = 37). A total of 20 healthy rats received intravenous PBS injections and served as the sham group. 1 day and 4 weeks after cell or PBS infusion, echocardiography was performed and cell retention was evaluated by quantitative real-time PCR. The fate of the migrated cells was detected through immunohistochemistry and the expression of inflammatory and anti-inflammatory protein was evaluated in lung and heart. The lung and heart function was also assessed. RESULTS: 1 day after cell implantation, the percentage of retained cells relative to the initial number of injected cells in heart and lung was 0.54 ± 0.19% and 51.69 ± 12.96%, respectively. After 4 weeks, it decreased to 0.24 ± 0.09% and 0.22 ± 0.17%. The entrapped MSCs did not differentiate into alveolar epithelial-like cells. Likewise, the left ventricular function was not improved. No adverse effects on lung function were observed after cell infusion. The expression of pro-inflammatory factors, including TNF-α, IL-1ß, malondialdehyde and myeloperoxidase, and anti-inflammatory factors, including TNF-α-induced protein 6, in the lung and heart was not significantly regulated after cell transplantation. CONCLUSION: Although the majority of intravenous infused cells were harbored in the lung, they did not cause deterioration of lung function. However, they did not activate the release of inflammatory/anti-inflammatory proteins, or stimulate angiogenesis or myogenesis in the old infarcted myocardium. Thus, intravenous administration of MSCs for chronic MI needs further experimental study.

Low-level laser irradiation alters cardiac cytokine expression following acute myocardial infarction: a potential mechanism for laser therapy.

OBJECTIVES: Low-level laser irradiation (LLLI) has the potential of exerting cardioprotective effect following myocardial infarction (MI). The authors hypothesized that LLLI could influence the expression of cardiac cytokines and contribute to the reversal of ventricular remodeling. BACKGROUND: LLLI regulates the expression of cytokines after tissue damage. However, little is known concerning the alteration of the cardiac cytokine expression profile after LLLI. METHODS: MI was created by coronary ligation. The surviving rats were divided randomly into laser and control groups. 33 rats were exposed to a diode laser (635 nm, 5 mW, CW, laser, beam spot size 0.8 cm(2), 6 mW/cm(2), 150 sec, 0.8 J, 1J/cm(2)) as laser group. Another 33 rats received only coronary ligation and served as control group. 28 rats received a thoracotomy without coronary ligation (sham group). One day after laser irradiation, 5 rats from each group were sacrificed and the heart tissues were analyzed by cytokine antibody arrays. Enzyme-linked immunosorbent assay (ELISA) was performed to confirm its reliability. Two weeks after MI, cardiac function and structure were evaluated by echocardiography and histological study. RESULTS: Cytokine antibody array indicated 4 cytokines were significantly changed after laser therapy. ELISA confirmed that granulocyte-macrophage colony stimulating factor and fractalkine were the cytokines involved in the response to therapeutic laser irradiation. However, there was no difference in cytokine release between various groups at 2 weeks after MI. Although LLLI did not improve the damaged heart function, it did reduce the infarct area expansion. CONCLUSIONS: The antibody-based protein array technology was applied for screening the cytokine expression profile following MI, with or without laser irradiation. The expression of multiple cytokines was regulated in the acute phase after LLLI. Our results revealed a potential novel mechanism for applying laser therapy to the treatment of heart disease.

SDF-1α inhibits hypoxia and serum deprivation-induced apoptosis in mesenchymal stem cells through PI3K/Akt and ERK1/2 signaling pathways.

Bone marrow-derived mesenchymal stem cells (BMSCs) have been demonstrated to be a promising cell sources for cardiac regeneration. Poor survival rate of transplanted BMSCs in infarcted myocardium attenuated its clinical application. It's reported that stromal-derived factor-1 (SDF-1) could protect progenitor cells including endothelial progenitor cells and embryonic stem cells from apoptosis. But little is known whether SDF-1α protein has the same protective effects on BMSCs under conditions of hypoxia and serum deprivation (hypoxia/SD). In present study, we verified that SDF-1α (0.50-2.0 µg/ml) inhibited hypoxia/SD induced apoptosis of BMSCs through mitochondrial pathway. After administration of SDF-1α, the loss of mitochondrial membrane potential and cytochrome c released from mitochondria to cytosol were significantly inhibited, and caspase 3 activity also declined. Furthermore, the effect of SDF-1α on mitochondrial pathway was neutralized by using PI3K inhibitor (Wortmannin) and ERK1/2 inhibitor (U0126). Our observations suggested that SDF-1α inhibits hypoxia/SD induced BMSCs apoptosis through PI3K/Akt and ERK1/2 signaling pathways. These data also imply that the anti-apoptotic effect mediated by SDF-1α may enhance cell survival after cell transplantation.

Alteration of parasympathetic/sympathetic ratio in the infarcted myocardium after Schwann cell transplantation modified electrophysiological function of heart: a novel antiarrhythmic therapy.

BACKGROUND: Neural remodeling after myocardial infarction (MI) may cause fatal ventricular arrhythmia. Schwann cells (SCs), which are important for neurogenesis, are dramatically reduced after MI. We investigated the feasibility of modifying nervous system regeneration after MI and the efficacy by which it may prevent ventricular arrhythmia following SC transplantation. METHODS AND RESULTS: Immediately after creation of MI, syngenic Lewis rats were randomized into cell transplantation (n=80) and control groups (n=72). SCs were isolated from sciatic nerves, and 5×10(6) cells were intramyocardially injected into the infarct region. Expression levels of myocardial nerve growth factor, vascular endothelial growth factor, growth-associated protein 43, connexin 43, and laminin in the SC group were significantly higher than control at 7 and 14 days after cell transplantation. Immunohistochemical staining illustrated increases in sympathetic and parasympathetic nerves in both groups. However, SC transplantation significantly increased the parasympathetic/sympathetic ratio at 14 days after cell injection. Dynamic electrocardiography and programmed electric stimulation were also performed. The SCs significantly decreased the low-/high-frequency ratio and arrhythmia score of programmed electric stimulation-induced ventricular arrhythmia at 2 weeks after cell injection. However, SCs did not restore heart function. CONCLUSIONS: Transplanted SCs in the infarcted myocardium secrete multiple biological molecules, which alter the ratio of parasympathetic/sympathetic nerve density to normalize irritable myocardium. SC transplantation might be a novel cell-based antiarrhythmic therapy following MI.

Impact of escaped bone marrow mesenchymal stromal cells on extracardiac organs after intramyocardial implantation in a rat myocardial infarction model.

Cell escape occurs after intramyocardial injection for treatment of myocardial infarction (MI) and then the migrated cells might be entrapped by extracardiac organs. We investigated the fate of migrated bone marrow-derived mesenchymal stromal cells (MSCs) and their impact on lung, liver, and spleen. MI model was created by coronary artery ligation in female Lewis rats. Three weeks after the ligation, bromodeoxyuridine (BrdU)-labeled male MSCs were directly injected into the infarcted area in the cell transplantation group (n = 22). The same volume of phosphate-buffered solution (PBS) was injected in the control group (n = 21). In the sham group (n = 10) intramyocardial injection of the same volume of PBS was performed in healthy rats. Four weeks later, echocardiography was performed and the cell retention was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry study was performed to identify the migrated cells. Heart function was improved after the cell injection. qRT-PCR results showed the percentage of retained cells in heart, spleen, liver, and lung ranked 3.63 ± 0.48%, 0.77 ± 0.13%, 0.68 ± 0.10%, 0.62 ± 0.11%, respectively, after cell transplantation. The implanted MSCs that escaped to liver, spleen, and lung did not differentiate into fibroblast, myofibroblast, or alveolar epithelial cells. However, the migrated MSCs in liver expressed functional hepatocyte marker. In conclusion, cell migration after intramyocardial injection did not result in deterioration of lung, liver, and spleen function. Our study might pave the way for new safety investigation of emerging cell resources and their impact on target and untargeted organs.