Influence of the timing of bronchoscopic alveolar lavage on children with adenovirus pneumonia: a comparative study.

BACKGROUND: Adenovirus pneumonia is prone to severe clinical and imaging manifestations in children. Bronchoscopic alveolar lavage (BAL) is an important adjunctive therapy for patients with severe imaging findings. The study aimed to evaluate the effect of the timing on the efficacy of bronchoalveolar lavage in children with adenovirus pneumonia. METHODS: This study included 134 patients with adenovirus pneumonia treated with BAL at Guangzhou Women and Children's Medical Center from January 2019 to January 2020.They were classified into the severe and mild groups. Based on the timing of BAL, each group was divided into the early BAL layer (received BAL within 1-9 days of the illness course) and the late BAL layer (received BAL within 10-14 days of the illness course). The clinical data of patients with different BAL timings were analyzed in two groups. RESULTS: Among the 134 patients, 70 were categorized into the mild group and 64 were categorized into the severe group. Of the 134 patients, 42 patients received BAL early (mild group: n = 21 and severe group: n = 21) and 92 patients received BAL later (mild group: n = 49 and severe group: n = 43). In the mild group, the fever and hospital duration were shorter in patients who received BAL early than in those who received BAL later (p < 0.05). However, in the severe group, there were no statistically significant differences in the fever and hospital duration between patients who received BAL early and those who received BAL later. However, the need for mechanical ventilation and the incidence of BAL complications, such as new need for oxygen, were higher in patients who received BAL early than in those who received BAL later in the severe group (p < 0.05). CONCLUSION: For mild adenovirus pneumonia, early BAL may shorten the fever and hospital duration. However, early BAL in severe cases might not shorten the course of the disease or improve prognosis and may even increase the risks of mechanical ventilation and BAL complications.

Two novel mutations in TCIRG1 induced infantile malignant osteopetrosis: a case report.

BACKGROUND: Infantile malignant osteopetrosis (IMO) is a rare autosomal recessive disease characterized by a higher bone density in bone marrow caused by the dysfunction of bone resorption. Clinically, IMO can be diagnosed with medical examination, bone mineral density test and whole genome sequencing. CASE PRESENTATION: We present the case of a 4-month-old male infant with abnormal skull development, hypocalcemia and premature closure of the cranial sutures. Due to the hyper bone density showed by his radiographic examination, which are characteristic patterns of IMO, we speculated that he might be an IMO patient. In order to confirm this diagnosis, a high-precision whole exome sequencing of the infant and his parents was performed. The analysis of high-precision whole exome sequencing results lead to the identification of two novel heterozygous mutations c.504-1G > C (a splicing site mutation) and c.1371delC (p.G458Afs*70, a frameshift mutation) in gene TCIRG1 derived from his parents. Therefore, we propose that there is a close association between these two mutations and the onset of IMO. CONCLUSIONS: To date, these two novel mutations in gene TCIRG1 have not been reported in the reference gene database of Chinese population. These variants have likewise not been reported outside of China in the Genome Aggregation Database (gnomAD). Our case suggests that the use of whole exome sequencing to detect these two mutations will improve the identification and early diagnosis of IMO, and more specifically, the identification of homozygous individuals with TCIRG1 gene mutation. We propose that these mutations in gene TCIRG1 could be a novel therapeutic target for the IMO in the future.

Differential proteomic analysis of children infected with respiratory syncytial virus

Respiratory syncytial virus (RSV) infection is the main cause of lower respiratory tract infection in children. However, there is no effective treatment for RSV infection. Here, we aimed to identify potential biomarkers to aid in the treatment of RSV infection. Children in the acute and convalescence phases of RSV infection were recruited and proteomic analysis was performed to identify differentially expressed proteins (DEPs). Subsequently, promising candidate proteins were determined by functional enrichment and protein-protein interaction network analysis, and underwent further validation by western blot both in clinical and mouse model samples. Among the 79 DEPs identified in RSV patient samples, 4 proteins (BPGM, TPI1, PRDX2, and CFL1) were confirmed to be significantly upregulated during RSV infection. Functional analysis showed that BPGM and TPI1 were mainly involved in glycolysis, indicating an association between RSV infection and the glycolysis metabolic pathway. Our findings provide insights into the proteomic profile during RSV infection and indicated that BPGM, TPI1, PRDX2, and CFL1 may be potential therapeutic biomarkers or targets for the treatment of RSV infection.

Clinical manifestations and risk factors of adenovirus respiratory infection in hospitalized children in Guangzhou, China during the 2011-2014 period.

To evaluate epidemiology and risk factors of severe adenovirus respiratory infection in hospitalized children in Guangzhou, China.A retrospective review study was conducted, and 542 children hospitalized for adenovirus respiratory infection, were included from January 2011 to December 2014. Patients were younger than 14 years. Disease severity was classified into severe and mild. Laboratory tests and clinical characteristics were analyzed for risk factors of adenovirus respiratory infection by multivariable logistic regression.Among these 542 children, 92.1% were aged < 6 years. Clinical diagnoses were upper respiratory infections in 11.6%, bronchiolitis in 16%, and mild pneumonia in 62.0% of children. Severe pneumonia rate was 10.3% (56/542) with a mortality rate of 0.9% (5/542). The cohort comprised 542 patients; 486 patients with mild adenovirus respiratory infection and 56 patients with severe adenovirus respiratory infection. Multivariable logistic regression was used to confirm associations between variables and adenovirus respiratory infection, after age and gender adjustment. Hospital stay, still significantly associated with adenovirus respiratory infection. Patients with longer hospital stay (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 1.13-1.28, P < .001), lower LYMPH (OR = 0.73 95% CI: 0.55-0.99, P = .039), and increased LDH (OR = 1.002, 95% CI: 1.001-1.003, P =  .001) had a higher risk of severe adenovirus respiratory infection.Adenovirus is a major pathogen in hospitalized children with respiratory infection. High serum LDH level and low lymphocyte count could be used as predictors of adenovirus respiratory infection severity in children.

Absence of PTHrP nuclear localization and C-terminus sequences leads to abnormal development of T cells.

Parathyroid hormone-related protein (PTHrP), a ubiquitously expressed protein, is composed of four functional domains including N-terminus, mid region, nuclear localization signal (NLS) and C-terminus. Under the direction of NLS, PTHrP can enter cell nucleus from cytoplasm and stimulate mitogenesis. Although PTHrP is considered to have important developmental roles, the role of PTHrP NLS and C-terminus in developmental process remains unknown, especially in T-cell development. Here, we used a knock-in mouse model, which expresses a truncated form of PTHrP missing the NLS (87-107) and C-terminus (108-139) of the protein, to examine the role of PTHrP NLS and C-terminus in T-cell development. Our results showed that the truncated PTHrP (1-84) led to abnormal subpopulations, impaired proliferation and increased apoptosis in the thymus, indicating that PTHrP is involved in the development of T cells, and the NLS and C-terminus part is necessary for the normal role of PTHrP in T-cell development.

Hypoxemia is an independent predictor of bronchiolitis obliterans following respiratory adenoviral infection in children.

Bronchiolitis obliterans (BO) is an uncommon and severe sequela of chronic obstructive lung disease in children that results from an insult to the lower respiratory tract. Few prognostic factors achieved worldwide acknowledgment. In the present study, we retrospectively collected the children with respiratory adenoviral infection and identified the predictive factors of BO. In the period between Jan 2011 and December 2014, the consecutive in-hospital acute respiratory infection children with positive result for adenovirus were enrolled into the present study. High resolution computerized tomography and clinical symptoms were utilized as the diagnostic technique for BO. Multivariate analysis using a Logistic proportional hazards model was used to test for independent predictors of BO. A total of 544 children were included with 14 (2.57 %) patients developed BO. Compared with children without BO, BO children presented higher LDH (523.5 vs. 348 IU/ml, p = 0.033), lower blood lymphocyte count (2.23 × 109/L vs. 3.24 × 109/L, p = 0.025) and higher incidence of hypoxemia (78.6 vs. 20.8 %, p = 0.000). They presented relatively persistent fever (15.5 vs. 7 days, p = 0.000) and needed longer treatment in hospital (19.5 vs. 7 days, p = 0.000). Concerning treatment, they were given more intravenous γ-globulin (85.7 vs. 36.8 %, p = 0.000), glucocorticoids (78.6 vs. 24.3 %, p = 0.000) and mechanical ventilation (35.7 vs. 5.5 %, p = 0.001). Multiple analyses determined that hypoxemia was the only independent predictor for BO. The present study identified hypoxemia as the independent predictive factor of BO in adenoviral infected children, which was a novel and sensitive predictor for BO.

Intranasal Delivery of Recombinant AAV Containing BDNF Fused with HA2TAT: a Potential Promising Therapy Strategy for Major Depressive Disorder.

Depression is a disturbing psychiatric disease with unsatisfied therapy. Not all patients are sensitive to anti-depressants currently in use, side-effects are unavoidable during therapy, and the cases with effectiveness are always accompanied with delayed onset of clinical efficacy. Delivering brain-derived neurotrophic factor (BDNF) to brain seems to be a promising therapy. However, a better approach to delivery is still rudimentary. The purpose of our present work is to look for a rapid-onset and long-lasting therapeutic strategy for major depressive disorder (MDD) by effectively delivering BDNF to brain. BDNF, fused with cell-penetrating peptides (TAT and HA2), was packaged in adenovirus associated virus (AAV) to construct the BDNF-HA2TAT/AAV for intranasally delivering BDNF to central nervous system (CNS) via nose-brain pathway. Intranasal administration of BDNF-HA2TAT/AAV to normal mice displayed anti-depression effect in forced swimming test when the delivery lasted relatively longer. The AAV applied to mice subjected to chronic mild stress (CMS) through intranasal administration for 10 days also alleviated depression-like behaviors. Western-blotting analysis revealed that BDNF-HA2TAT/AAV nasal administration enhanced hippocampal BDNF content. These results indicate intranasal administration of constructed BDNF-HA2TAT/AAV exerts anti-depression effect in CMS mice by increasing hippocampal BDNF, suggesting that this strategy holds a promising therapeutic potential for MDD.

Intranasal Delivery of Recombinant NT4-NAP/AAV Exerts Potential Antidepressant Effect.

The present study was designed to construct a recombinant adeno-associated virus (rAAV) which can express NAP in the brain and examine whether this virus can produce antidepressant effects on C57 BL/6 mice that had been subjected to open field test and forced swimming test, via nose-to-brain pathway. When the recombinant plasmid pGEM-T Easy/NT4-NAP was digested by EcoRI, 297 bp fragments can be obtained and NT4-NAP sequence was consistent with the designed sequence confirmed by DNA sequencing. When the recombinant plasmid pSSCMV/NT4-NAP was digested by EcoRI, 297 bp fragments is visible. Immunohistochemical staining of fibroblasts revealed that expression of NAP was detected in NT4-NAP/AAV group. Intranasal delivery of NT4-NAP/AAV significantly reduced immobility time when the FST was performed after 1 day from the last administration. The effects observed in the FST could not be attributed to non-specific increases in activity since intranasal delivery of NT4-NAP/AAV did not alter the behavior of the mice during the open field test. The results indicated that a recombinant AAV vector which could express NAP in cells was successfully constructed and NAP may be a potential target for therapeutic action of antidepressant treatment.

[Arthroscopic single bundle anterior cruciate ligament anatomical reconstruction with remnant preservation].

OBJECTIVE: To investigate the feasibility and clinical effects of single bundle anterior cruciate ligament anatomical reconstruction with remnant preservation. METHODS: From October 2007 to November 2009, 17 patients (10 male and 7 female, ranging in age from 28 to 62 years, with an average of 39.3 years) with posterior cruciate ligament injuries were treated with single bundle anatomical reconstruction with remnant preservation. Nine patients had the injuries caused by traffic accident; 6 patients caused by falling down; and 2 patients caused by sports injuries. The average time from injury to surgery was 8.5 days (ranging from 2 to 14 days). The international knee documentation committee knee evaluation form (IKDC) and Lysholm were used to analysis the effect of surgery. RESULTS: All the patients obtained the follow-up and the average time was 29.5 months (ranging from 24 to 39 months). There were no complications such as injuries of popliteal fossa artery, tibial nerves or peroneal nerve. Twelve patients had knee joint recovering to normal; 1 patient had stiff joints and was treated with arthroscopic surgery to release after 6 months,who had postoperative flexion lack of 20 degree and straight to normal. Three patients had flexion loss of 5 to 10 degree, and 1 patient had hyperextension limitation of 5 degree. Posterior drawer test in 17 patients and the Lachman test were negative. IKDC scores of the 17 patients achieved normal(16 patients) or near normal(1 patient). IKDC overall score normal in 16 patients (94.1%), close to normal in 1 case (5.9%). The IKDC subjective score was 94.3+/-5.1 and Lysholm score was 94.7+/-3.1 at the latest follow-up. CONCLUSION: The single bundle anterior cruciate ligament with remnant preservation anatomical reconstruction can provide good clinical results.

[Anatomical study on the femoral tunnel anatomy reconstruction of anterior cruciate ligament].

OBJECTIVE: To measure anatomical data of the femoral tunnel anatomy reconstruction of anterior cruciate ligament (ACL), so provide anatomical basis for clinical anatomy reconstruction of ACL. METHODS: There were 30 adults' cadaveric knee specimens. The ACL femoral tunnel was reconstructed through anterior medial approach (AMP) in genuflex position of 120 degree, and was marked by Kirschner. The soft tissue of the specimen was removed and the femoral condyle was split at the middle side. The index including length of the femoral tunnel, the distance from internal opening of tunnel to cortical edge of femoral condyle and vertical distance to the top of femoral intercondylar notch were measured. Then the time position of internal opening of tunnel in the intercondylar notch was recorded, and the location of outside opening of tunnel to the femoral condyle was detected. RESULTS: The mean length of the femoral tunnel was (36.35 +/- 3.14) mm (ranged, 30.65 to 42.35 mm). The distance from internal opening of tunnel to cortical edge of femoral condyle was (17.84 +/- 3.35) mm (ranged, 14.02 to 23.49 mm), vertical distance to the top of femoral intercondylar notch was (14.05 +/- 2.32) mm (ranged, 9.17 to 20.08 mm). According to the way of circular dial,internal opening of tunnel located at 02:30 +/- 00:10 (ranged, 01:50 to 02:50) in the left knee,and 09:30 +/- 0:15 (ranged, 08:30 to 10:40) in the right knee. The outside opening of femoral tunnel located at (3.16 +/- 2.51) mm (ranged, 1.61 to 6.30 mm) to the proximal end of external epicondyle of femur, and (4.25 +/- 2.16) mm (ranged, 1.73 to 8.52 mm) to the posterior of external epicondyle of femur. CONCLUSION: The anatomical features of femoral tunnel for reconstruction of ACL is revealed,which will provide anatomical basis for clinical practice.

Endoscope-assisted removal of intraosseous schwannoma with preservation of inferior alveolar nerve.

The use of endoscopes in oral and maxillofacial surgery has been well documented. The advantage of no external scar and minimal invasiveness makes endoscopic technique gradually more popular. This article will describe a rare case of an intraosseous inferior alveolar nerve schwannoma and its removal using endoscope. The surgical technique and preservation of the inferior alveolar nerve will be described and illustrated. The advantages and disadvantages of the approach will be discussed.

Oestradiol supplement minimises coronary occlusion-induced myocardial infarction and ventricular dysfunction in oophorectomised female rats.

BACKGROUND: Endogenous oestrogen deficiency after menopause is associated with high risk of acute cardiac events and the protection of exogenous oestrogen supplements remains uncertain. This study investigates whether oestrogen therapy protects the heart from ischemic injury in oophorectomised rats. METHODS: Sexually mature female Sprague-Dawley rats (6 for each group) with bilateral oophorectomy underwent selective ligation (occlusion) of left coronary artery for 4 weeks. 17ß-oestradiol (E2) supplements (10 µg, i.m., every other day) were started before (preventive-therapeutic supplement) or after coronary occlusion (therapeutic supplement). RESULTS: In oophorectomised rats plasma levels of E2 declined from 1301 ± 80 to 196 ± 48 pmol/L (p<0.01) and cardiac expression of oestrogen receptors (ER) decreased by ∼60%. E2 supplements recovered the ER expression. Selective ligation of left coronary led myocardial infarction in the left ventricle, with an increase in plasma cardiac troponin I (cTn-I), decrease in systolic blood pressure (SBP), and reduction of left ventricular pressures. Preventive-therapeutic but not therapeutic E2 supplement reduced cTn-I levels (from 21.9 ± 2.0 to 6.0 ± 0.3 ng/mL, p<0.01), minimised infarction (from 37.0 ± 1.2% to 18.1 ± 2.3%, p<0.05), increased SBP (from 82 ± 4.2 to 97 ± 4.4mm Hg, p<0.05), and improved left ventricular end pressures in the oophorectomised rats following coronary occlusion. CONCLUSION: Postmenopausal (ooporectomised) oestrogen supplement commenced before establishment of myocardial ischemia minimises myocardial infarction and ventricular dysfunction following the coronary artery occlusion. Cellular and molecular mechanisms underlying the cardiac protection of oestrogen therapy remain unclear, in which activation of cardiac ER expression and increasing in circulating CD90(+) stem cells may be involved.

Oral delivery of tumor-targeting Salmonella exhibits promising therapeutic efficacy and low toxicity.

Tumor-targeting bacteria have been developed as powerful anticancer agents. Salmonella typhimurium VNP20009, a representative tumor-targeting strain, has been systemically administered as a single-agent therapy at doses of 1 x 10(6) to 3 x 10(6) colony-forming unit (cfu)/mouse, or in combination with other antitumor agents at doses of 1 x 10(4) to 2 x 10(5) cfu/mouse. Recently, we reported that oral delivery of VNP20009 at the dose of 1 x 10(9) cfu/mouse induced significant anticancer effects comparable to that induced by systemic administration of this strain at 1 x 10(4) cfu/mouse. To further address the efficacy and safety of oral administration of bacteria, here we performed a systemically comparative analysis of anticancer efficacy and toxicity of VNP20009 administered: (i) orally at a dose of 1 x 10(9) cfu/mouse (VNP9-oral); (ii) intraperitoneally at a dose of 1 x 10(4) cfu/mouse (VNP4-i.p.); or (iii) intraperitoneally at a dose of 1 x 10(6) cfu/mouse in tumor-free and tumor-bearing murine models. The results showed that VNP9-oral, similar to VNP4-i.p., induced significant tumor growth inhibition whereas VNP6-i.p. induced better anticancer effect in the B16F10 melanoma model. Among three treatments, VNP9-oral induced the mildest and reversible toxicity whereas VNP6-i.p. resulted in the most serious and irreversible toxicities when compared to other two treatments. Moreover, the combination of VNP9-oral with a low dose of chemotherapeutics produced comparable antitumor effects but displayed significantly reduced toxicity when compared to VNP6-i.p. The findings demonstrated that oral administration, as a novel avenue in the application of bacteria, is highly safe and effective. Moreover, the present preclinical study should facilitate the optimization of bacterial therapies with improved anticancer efficacy and reduced adverse effects in future clinical trials.

[Sinoatrial node cells phenotype expression is induced by direct bone marrow stem cells contact with sinoatrial node cells].

OBJECTIVE: To observe the differentiation of bone mesenchymal stem cells (BMSCs) co-cultured with purified sinoatrial node cells (SNC) of neonate rats. METHODS: SNC from neonatal SD rat were cultured and purified with differential attachment method and labeled with BrdU. Rat BMSCs were isolated by a Percoll's gradient solution and cultured in DMEM. After 2 passages, these BMSCs were transfected with pEGFP-N1 by Lipofectamine and labeled with GFP. EGFP-BMSC were co-cultured with SNC in a rate of 1:5 for 1 week. EGFP-BMSC cultured in SNC culture medium served as controls. SNC marker hyperpolarization activated cyclic nucleotide gated cation channel 4 (HCN4) and connexin 45 (Cx45) expressions were determined by immunofluorescence staining. RESULT: Positive immunofluorescence staining against HCN4 and Cx45 were detected in EGFP-BMSC co-cultured with SNC but not in EGFP-BMSC cultured in SNC culture medium. CONCLUSION: Direct cell-to-cell contact between BMSCs and SNC cells may induce BMSCs differentiation into sinus node-like cells.

[Stress distribution of surgically assisted tooth-borne rapid maxillary expansion via three different types of osteotomies].

PURPOSE: To investigate the stress distribution of craniofacial bones during surgically assisted tooth-borne rapid maxillary expansion (SARME) via three different osteotomies. METHODS: Three-dimensional finite element model of craniofacial bones with a tooth-borne appliance was generated. According to the different osteotomies, the models were categorized as three groups: Type I-isolated midpalatal osteotomy, Type II-Le Fort I and midpalatal osteotomies, Type III-Le Fort I and midpalatal osteotomies and bilateral pterygomaxillary disjunction. In all three models, with 4 different displacements, von-Mises stress was measured and analysed at 11 anatomical structures of the craniofacial bones. RESULTS: An obvious reduction of the stress was observed followed by the larger extent of the surgery. The maximum stress of the bones was only noticed in Type I model. Stress on lamina of the pterygoid acutely increased in the Type II model compared with the Type I model. In Type III model, after separation of the pterygomaxillary junctions, stress on lamina of the pterygoid decreased rapidly and meanwhile stressed on the majority of the midfacial bones also decreased. In Type III osteotomies, anatomical structures of the upper craniofacial bones suffered from an increase of the stress. CONCLUSIONS: Surgical procedures would be of great help to reduce the stress on the craniofacial region in the rapid maxillary expansion postoperatively. Fractures of the cranial base may occur at a greater chance because of stress focusing on lamina of the pterygoid. So, separation of the pterygomaxillary junctions during the operation is suggested. Increasing stress on the upper craniofacial bones can be observed after separation of the pterygomaxillary junctions due to changes of stress transduction pathways.

Enhanced therapeutic effect by combination of tumor-targeting Salmonella and endostatin in murine melanoma model.

The growth of tumor is angiogenesis-dependent and it often contains hypoxia and necrotic areas. Salmonella VNP20009 could target and replicate in hypoxia and necrotic areas within tumor and induce antitumor effect. Angiogenesis inhibitor endostatin could reduce tumor angiogenesis and inhibit its growth. However, in the phase I trials of VNP20009 and endostatin at the maximum-tolerated dose, no antitumor effects for bacteria therapy and minor therapeutic effects for endostatin treatment were seen. The ineffectiveness of these agents in clinical trials suggests that the combination of these agents with synergic modalities might be necessary. Here we described antitumor effects mediated by the combination of VNP20009 with recombinant human endostatin in B16F10 murine melanoma model with the aim to exploit tumor-targeting of bacteria and anti-angiogenesis strategy to enhance therapeutic efficacy. Combination therapy of these agents significantly enhanced antitumor effects by inducing greater tumor growth inhibition, more severe tumor tissue necrosis as well as less blood vessel density than those induced by either of treatments. The findings suggest that the combination of tumor-targeting bacteria with angiogenesis inhibitor might be of value for the treatment of solid tumors.

Migration of intravenously grafted mesenchymal stem cells to injured heart in rats.

The present study aimed to determine the role of tissue injury in migration of mesenchymal stem cells (MSCs) intravenously transplanted into heart and to establish experimental basis for improving stem cell therapy in its targeting and effectiveness. MSCs were isolated from bone marrow of male Sprague-Dawley rats and purified by density centrifuge and adhered to the culture plate in vitro. Female rats were divided randomly into four groups. Myocardial ischemia (MI) transplanted group received MSCs infusion through tail vein 3 h after MI and compared with sham-operated group or normal group with MSCs infusion, or control group received culture medium infusion. MI was created in female rats by ligating the left anterior descending coronary artery. The heart was harvested 1 week and 8 weeks after transplantation. The characteristics of migration of MSCs to heart were detected with expression of sry gene of Y chromosome by using fluorescence in situ hybridization (FISH). Ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope (TEM). One week or 8 weeks after transplantation, sry positive cells were observed in the cardiac tissue in both of MI transplanted group and sham-operated group, the number of sry positive cells being significantly higher in MI transplanted group (P<0.01). No significant difference was found in the number of sry positive cells between 1 week and 8 weeks after transplantation. No sry positive cells were observed in the hearts of control and normal group. In addition, the ultrastructure of some cells located in the peri-infarct area of MI rats with MSCs transplantation was similar to that of MSCs cultured in vitro. These results indicate that MSCs are capable of migrating towards ischemic myocardium in vivo and the fastigium of migration might appear around 1 week after MI. The tissue injury and its degree play an important role in the migration of MSCs.

[Ultrastructural changes of rat ischemic myocardium after bone marrow mesenchymal stem cell transplantation].

OBJECTIVE: To observe the ultrastructural changes of ischemic myocardium of rats after bone marrow mesenchymal stem cells (MSCs) transplantation. METHODS: Rat models of myocardial ischemia were established by ligating the descending anterior branch of the left coronary artery. The isolated and in vitro cultured MSCs labeled with 4' 6-diamidine-2-phenylindole (DAPI) were injected into the rats via the tail vein and the hearts of the rats were taken 1 week and 8 weeks after transplantation, respectively, for observation under fluorescence microscopy. The ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope. RESULTS: The third passage of cultured MSCs growing in colonies possessed good homogeneity. One week and 8 weeks after transplantation, DAPI-labeled cells were observed in the heart of the recipient rats, but not in the hearts of control rats. One week after transplantation, ultrastructural observation identified a small number of cells in the peripherals of the infarct area of the recipient rats with similar morphology to that of MSCs cultured in vitro. At 8 weeks,a large number of capillaries were seen in the ischemic myocardium on the peripheral of the infarct area. Ultrastructural observation also revealed some immature myocytes surviving in the ischemic region. CONCLUSION: MSCs is capable in vivo of homing to the ischemic myocardium via the blood circulation, and promote regeneration of the myocardium and blood vessels.

[Differentiation of mesenchymal stem cells into cardiomyocytes induced by cardiomyocytes].

OBJECTIVE: To investigate the role of adult cardiomyocytes in the differentiation of mesenchymal stem cells (MSCs) into cardiomyocytes. METHODS: Rat MSCs were isolated by a Percoll's gradient solution and cultured in low-glucose Dulbecco' s modified Eagle' s medium (DMEM). After 2 passages, cell-surface antigen CD34, CD71 and CD90 for rat MSCs were determined by flow cytometry, and these MSCs were transfected with pEGFP-N3 by Lipofectamine2000. Then those MSCs labeled with GFP, were cultured in contacted, nocontacted and conditioned with adult rat myocardiocytes. Immunofluorescence staining against alpha-actin, desmin, and troponin-T were performed after 1 week. RESULTS: Immunofluorescence staining was positive against alpha-actin, desmin, and troponin-T on MSCs in contacted culture group. In contrast, no alpha-actin, desmin, and troponin-T expression on MSCs were observed in the noncontacted culture group and the conditioned culture group. CONCLUSION: Direct cell-to-cell contact between MSCs and adult cardiomyocytes may induce differentiation of MSCs into cardiomyocytes.