Stretchable, Adhesive, and Biocompatible Hydrogel Based on Iron-Dopamine Complexes.

Hydrogels' exceptional mechanical strength and skin-adhesion characteristics offer significant advantages for various applications, particularly in the fields of tissue adhesion and wearable sensors. Herein, we incorporated a combination of metal-coordination and hydrogen-bonding forces in the design of stretchable and adhesive hydrogels. We synthesized four hydrogels, namely PAID-0, PAID-1, PAID-2, and PAID-3, consisting of acrylamide (AAM), N,N'-methylene-bis-acrylamide (MBA), and methacrylic-modified dopamine (DA). The impact of different ratios of iron (III) ions to DA on each hydrogel's performance was investigated. Our results demonstrate that the incorporation of iron-dopamine complexes significantly enhances the mechanical strength of the hydrogel. Interestingly, as the DA content increased, we observed a continuous and substantial improvement in both the stretchability and skin adhesiveness of the hydrogel. Among the hydrogels tested, PAID-3, which exhibited optimal mechanical properties, was selected for adhesion testing on various materials. Impressively, PAID-3 demonstrated excellent adhesion to diverse materials and, combined with the low cytotoxicity of PAID hydrogel, holds great promise as an innovative option for biomedical engineering applications.

Preoperative and postoperative clinical signatures of postgastrectomy venous thromboembolism in patients with gastric cancer: A retrospective cohort study.

BACKGROUND: This study aimed to identify preoperative and postoperative risk factors of venous thromboembolism (VTE) after gastrectomy in gastric cancer (GC) patients. METHODS: 757 GC patients underwent gastrectomy at our institution and 246 patients with elevated postoperative D-dimer levels who received Doppler ultrasonography of lower/upper extremity veins were enrolled. Clinicopathological factors data were collected, and the differences in clinicopathological factors between postoperative VTE (+) and VTE (-) groups were analyzed. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors of postgastrectomy VTE. RESULTS: Of 246 patients with elevated postgastrectomy D-dimer concentrations, 74 patients showed thrombosis in lower/upper extremity veins. Among preoperative factors, age, WBC level, D-dimer concentration, and blood glucose level were significantly higher in the postoperative VTE (+) group. Among the postoperative factors, hemoglobin level was significantly lower in the postoperative VTE (+) group. Among the pathological factors, tumor stage, depth of invasion and TNM classification indicated higher malignancy in the postoperative VTE (+) group. Univariate logistic regression analysis indicated age, preoperative blood glucose level, postoperative hemoglobin level, tumor stage, depth of invasion, and TNM classification as the independent risk factors for postgastrectomy VTE, whereas multivariate logistic regression analysis revealed age and tumor stage as independent risk factors for postgastrectomy VTE. CONCLUSION: Our study revealed that age, preoperative blood glucose level, postoperative anemia, and tumor malignancy were independent risk factors for GC patients exhibiting postgastrectomy VTE. Therefore, the perioperative monitoring, assessment and management of risk factors are important in achieving better outcomes after gastrectomy.

Platelets as a prognostic marker for sepsis: A cohort study from the MIMIC-III database.

During sepsis, platelets dysfunction contributes to organ dysfunction. Studies on platelets dysfunction in the long-term prognosis of sepsis are lacking. The aim of this study was to assess the role of platelets in the long-term prognosis of sepsis patients.A total of 4576 sepsis patients were extracted from MIMIC III Database. Survival was analyzed by the Kaplan-Meier method. Univariate and multivariate cox analyses were performed to identify prognostic factors. Significant prognostic factors were combined to build a nomogram to predict 1 year overall survival (OS). The discriminative ability and predictive accuracy of the nomogram were evaluated using the receiver operating characteristic curve (ROC) analysis and calibration curves used for sepsis.The more abnormal the platelet level, the worse prognosis of patients. After final regression analysis, age, blood urea nitrogen, platelets, international normalized ratio, partial thromboplastin time, potassium, hemoglobin, white blood cell count, organ failures were found to be independent predictors of 1 year OS of sepsis patient and were entered into a nomogram. The nomogram showed a robust discrimination, with an area under the receiver operating characteristic curve of 0.752. The calibration curves for the probability of the prognosis of sepsis patients showed optimal agreement between the probability as predicted by the nomogram and the actual probability.Platelet was an independent prognostic predictor of 1 year OS for patients with sepsis. Platelet-related nomogram that can predict the 1 year OS of sepsis patients. It revealed optimal discrimination and calibration, indicating that the nomogram may have clinical utility.

Elevated ROS depress mitochondrial oxygen utilization efficiency in cardiomyocytes during acute hypoxia.

Mitochondria are important sites for the production of ATP and the generation of ROS in cells. However, whether acute hypoxia increases ROS generation in cells or affects ATP production remains unclear, and therefore, monitoring the changes in ATP and ROS in living cells in real time is important. In this study, cardiomyocytes were transfected with RoGFP for ROS detection and MitGO-Ateam2 for ATP detection, whereby ROS and ATP production in cardiomyocytes were respectively monitored in real time. Furthermore, the oxygen consumption rate (OCR) of cardiomyocytes was measured. Similar results were produced for adult and neonatal rat cardiomyocytes. Hypoxia (1% O2) reduced the basal OCR, ATP-linked OCR, and maximal OCR in cardiomyocytes compared with these OCR levels in the cardiomyocytes in the normoxic group (21% O2). However, ATP-linked OCR, normalized to maximal OCR, was increased during hypoxia, indicating that the electron leakage of complex III exacerbated the increase of ATP-linked oxygen consumption during hypoxia and vice versa. Combined with the result that cardiomyocytes expressing MitGO-Ateam2 showed a significant decrease in ATP production during hypoxia compared with that of normoxic group, acute hypoxia might depress the mitochondrial oxygen utilization efficiency of the cardiomyocytes. Moreover, cardiomyocytes expressing Cyto-RoGFP or IMS-RoGFP showed an increase in ROS generation in the cytosol and the mitochondrial intermembrane space (IMS) during hypoxia. All of these results indicate that acute hypoxia generated more ROS in complex III and increased mitochondrial oxygen consumption, leading to less ATP production. In conclusion, acute hypoxia depresses the mitochondrial oxygen utilization efficiency by decreasing ATP production and increasing oxygen consumption as a result of the enhanced ROS generation at mitochondrial complex III.

Evaluation of the clinical diagnostic value of traditional inflammatory markers and novel biomarkers in intracellular bacterial bloodstream infections.

OBJECTIVES: The clinical symptoms of the patients with intracellular bacterial bloodstream infections (Intra-bac BSIs) are atypical, and no early and accurate diagnostic biomarkers exist, which can easily lead to misdiagnosis, inappropriate and delayed treatment. Therefore, it is imperative to find novel biomarkers to help clinical diagnosis of Intra-bac BSIs. The present study was initiated to evaluate the diagnostic values of traditional inflammatory biomarkers (PCT, WBC and NEU% in identifying the patients with Intra-bac BSIs, and to further explore into the possibility of using suPAR and sCD14-ST as novel biomarkers for Intra-bac BSIs. METHODS: A multi-center retrospective study was conducted in three teaching hospitals in Chongqing. A total of 146 cases with BSIs, including 73 cases with Intra-bac BSIs and 73 cases with extracellular bacterial BSIs (Extra-bac BSIs) were enrolled in the retrospective study. We then prospectively enrolled 34 patients with Intra-bac BSIs, 34 patients with Extra-bac BSIs, 34 patients with viral infection and with normal medical examination results as a control group for further detection of sCD14-ST and suPAR by ELISA. RESULTS: PCT levels, WBC counts and NEU% in patients with Intra-bac BSIs were not increased or minimally increased, they were significantly lower than that with Extra-bac BSIs (P < 0.05), especially those with the Brucella bacterial BSIs, demonstrated a respective negative rate of 84% and 92% for PCT and WBC counts. In the prospective study, the levels of suPAR and sCD14-ST in both the Intra-bac BSIs and the Extra-bac BSIs groups were significantly higher than those in the viral infection group and normal control group (P < 0.05). The areas under the curve (AUC) of Intra-bac BSIs were 0.830 for suPAR, and 0.855 for sCD14-ST. The sensitivity, specificity, Youden's index for suPAR and sCD14-ST were respectively 76.5%, 88.2%, 0.647 and 94.1%, 64.7%, 0.588. CONCLUSIONS: Our multi-center study demonstrated that while the traditional inflammatory markers such as PCT, WBC counts, NEU% could not be served as promising diagnostic markers for Intra-bac BSIs; CRP can help guide the diagnosis of Intra-bac BSIs; Both suPAR and sCD14-ST could be considered as novel diagnostic biomarkers for Intra-bac BSIs as they showed good diagnostic accuracies in Intra-bac BSIs, especially suPAR.

[Effect of human bone marrow mesenchymal stem cells on invasion of tongue squamous cell carcinoma cell line Cal-27].

PURPOSE: To investigate the effect of human bone marrow mesenchymal stem cells (hBM-MSCs) on invasion of tongue squamous cell carcinoma cell line Cal-27 and its mechanism. METHODS: hBM-MSCs and Cal-27 were cultured respectively, and the morphology of the cells was observed under an inverted microscope. The co-cultured Cal-27 cells were obtained by co-culture of hBM-MSCs and Cal-27. The migration area of Cal-27 was observed by scratch test;transwell migration and invasion experiments were performed to observe migration and invasion of Cal-27, and a bar graph was then drawn. Fluorescence quantitative PCR was used to observe the effect of hBM-MSCs on gene expression of the tumor markers E-cadherin, twist, slug, snail, MMP-2 and MMP-9. Western blot was used to observe the effect of hBM-MSCs on protein expression of MMP-2 and MMP-9, related to the invasion of Cal-27. SPSS 19.0 software package was used for statistical analysis of the data. RESULTS: Under the influence of hBM-MSCs, the invasion of Cal-27 was promoted, accompanied by down-regulation of E-cadherin, up-regulation of twist, slug, snail, MMP-2, MMP-9 and up-regulation of MMP-2 and MMP-9 expression. CONCLUSIONS: hBM-MSCs can promote invasion of Cal-27 cells, which may be related to up-regulation of the expression of tumor markers related to invasion of Cal-27 cells.

[Effects of farnesyltransferase silencing on the migration and invasion of tongue squamous cell carcinoma].

OBJECTIVE: This study aimed to explore the effects of silencing farnesyltransferase (FTase) on the migration and invasion of tongue squamous cell carcinoma (TSCC) through RNA interference. METHODS: TSCC cells (CAL27 and SCC-4) were cultured in vitro and then transfected with siRNA to silence FTase expression. The tested cells were categorized as follows: experimental group (three RNA interference groups), negative control group, and blank control group. mRNA expression of FTase and HRAS in each group was analyzed by quantitative real-time polymerase chain reaction. On the basis of FTase mRNA expression, the optimum interference group (highest silencing efficiency) was selected as the experimental group for further study. The protein expression of FTase, HRAS, p65, p-p65(S536), matrix metalloprotein-9 (MMP-9), hypoxia inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) was analyzed by Western blot. The invasion and migration abilities of TSCC cells were determined by Transwell invasion assay and cell wound healing assay. RESULTS: The mRNA and protein expression of FTase in the experimental group decreased compared with that in the negative control and blank control groups (P<0.05). The mRNA and protein expression of HRAS was not significantly different among the groups (P>0.05). In the experimental group, the protein expression of p-p65(S536), MMP-9, HIF-1α, and VEGF decreased (P<0.05), whereas that of p65 had no significant change (P>0.05). The migration and invasion abilities of the experimental group were inhibited significantly (P<0.05). CONCLUSIONS: Silencing FTase in vitro could effectively downregulate its expression in TSCC cell lines and reduce the migration and invasion abilities to a certain extent. FTase could be a new gene therapy target of TSCC, and this research provided a new idea for the clinical treatment of TSCC.

Microrna Expression Profiling of Macrophage Line Raw264.7 Infected by Candida Albicans.

INTRODUCTION: The aim of this study was to clarify the microRNA (miRNA) expression profiles of RAW264.7 macrophages infected by Candida albicans to elucidate the roles of differentially expressed miRNAs and to further explore the mechanisms underlying the immune response to C. albicans infection. METHODS: High-throughput miRNA microarray analysis was performed to detect differentially expressed miRNAs in control and C. albicans-infected RAW264.7 cells. Quantitative real-time PCR analysis was used to verify the microarray results. Target genes of differentially expressed miRNAs were predicted with bioinformatics software. The cell biological processes and signaling pathways of these miRNA-targeted genes involved in C. albicans infection were predicted by gene ontology (GO) enrichment and pathway analyses. RESULTS: Significant upregulation of eight miRNAs (mmu-miR-140-5p, mmu-miR-96-5p, mmu-miR-8109, mmu-miR-466i-3p, mmu-miR-222-5p, mmu-miR-301b-3p, mmu-miR-466g, and mmu-miR-7235-5p) and downregulation of eight miRNAs (mmu-miR-3154, mmu-miR-223-3p, mmu-miR-494-3p, mmu-miR-6908-5p, mmu-miR-188-5p, mmu-miR-6769b-5p, mmu-miR-7002-5p, and mmu-miR-1224-5p) were observed, as compared with the control (fold change ≥2.0 and P < 0.05). GO analysis revealed that both mmu-miR-140-5p and mmu-miR-223-3p participated in immune responses, inflammatory reactions, and cell apoptosis in C. albicans infection. Also, the MAPK signaling pathway was found to play an important role in the immune response against C. albicans infection. CONCLUSIONS: This study revealed comprehensive expression and functional profiles of differentially expressed miRNAs in macrophage RAW264.7 cells infected by C. albicans. These findings should help to further elucidate the mechanisms underlying the immune response to C. albicans infection.

Streptococcus pneumoniae induces autophagy through the inhibition of the PI3K-I/Akt/mTOR pathway and ROS hypergeneration in A549 cells.

The present study focused on the action mechanism of S. pneumoniae (Sp) in inducing autophagy in human alveolar epithelial cells. Sp, a gram-positive extracellular bacterium, activates autophagy with considerably increased microtuble-associated protein light chain 3 (LC3) punctation in A549 cells. The accumulation of typical autophagosomes and conjugation of LC3 to phosphatidylethanolamine were observed in Sp-infected cells as an indication of autophagy. Using the pneumolysin (PLY) mutant, we successfully demonstrated that PLY is involved in initiating autophagy without affecting the expression levels of PI3K-III and Beclin1. PLY-mediated autophagy depends on the inhibition of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway. Furthermore, Sp could also lead to the reactive oxygen species (ROS) hypergeneration in A549 cells. Taken together, Sp infection-induced autophagy is PLY-mediated through ROS hypergeneration and mTOR inhibition. PI3K-I and rapamycin (autophagy inducers) enhanced bacterial clearance, whereas wortmannin (autophagy inhibitor) and acetylcysteine (ROS inhibitor) reduced intracellular bacteria clearance. Thus, Sp-induced autophagy represents a host-protective mechanism, providing new insight into the pathogenesis of respiratory tract Sp infection.

Multisite phosphorylation of Bcl-2 via protein kinase Cδ facilitates apoptosis of hypertrophic cardiomyocytes.

Activated protein kinase Cδ (PKCδ) associated with cardiac hypertrophy moves from the cytoplasm to the mitochondria and subsequently triggers the apoptotic signalling pathway. The underlying mechanisms remain unknown. The aim of the present study was to investigate whether mitochondrial translocation of PKCδ phosphorylates multiple sites of Bcl-2, resulting in an imbalance between Bcl-2 and Bak or Bax, thus enhancing the susceptibility of hypertrophic cardiomyocytes to angiotensin II (AngII)-induced apoptosis. Chronic pressure overload was induced by transverse aortic constriction (TAC) in rats. The apoptotic rate increased in hypertrophied cardiomyocytes. In AngII-treated hearts (10 nmol/L, 60 min), there was an increase in the number of TERMINAL deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL)-positive cells; PKCδ inhibition with 500 nmol/L δV1-1 for 60 min prevented the AngII-induced increase in apoptosis. In the hypertrophied myocardium, PKCδ expression increased, whereas that of Bcl-2 decreased compared with the synchronous control. Treatment of hearts with 10 nmol/L AngII for 60 min activated PKCδ and induced translocation of PKCδ to the mitochondria, where activated PKCδ facilitated the phosphorylation of Bcl-2 at serine-87 and serine-70 sites. The multisite phosphorylated Bcl-2 was released from the mitochondria, and exhibited reduced affinity for Bak and Bax. The imbalance between Bcl-2 and Bak/Bax induced the release of mitochondrial cytochrome c and then activated the caspase 3 apoptotic pathway during AngII stimulation (10 nmol/L, 60 min) of hypertrophied cardiomyocytes. Inhibition of PKCδ reduced these effects of AngII. The results suggest that PKCδ can counteract the anti-apoptotic effect of Bcl-2 and may promote cardiomyocyte apoptosis through multisite phosphorylation of Bcl-2 in hypertrophied cardiomyocytes.

[Autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction rats].

Cardiac autophagy dramatically increases in heart failure induced by sustained pressure overload. However, it has not yet been addressed if enhanced autophagy plays a role in protecting myocardium or mediating progression from compensative hypertrophy to heart failure. The aim of the present study was to detect autophagic flux of cardiomyocytes from 20-week transverse abdominal aortic constriction (TAC) rats. Fasting rats were used as the positive control for detecting cardiac autophagy. Echocardiography was applied to find the changes of cardiac structure and function. Immunofluorescent histochemistry and Western blot were used to analyze the related biomolecular indexes reflecting cardiac autophagic flux. After the previous methods for detecting cardiac autophagy were confirmed, the autophagic flux in cardiomyocytes of rats subjected to 20-week TAC was examined. The results showed that fasting had no obvious influence on parameters of cardiac structure in rats, including interventricular septal wall thickness and left ventricle posterior wall thickness, but heart rate, diastolic left ventricle internal dimension, fractional shortening of left ventricle dimension, ejection fraction and mitral inflow velocity decreased in rats after fasting for 3 d. Meanwhile, positively stained particles of LC3 and cathepsin D, but not ubiquitin and complement 9, distributed within cardiomyocytes of 3-day fasting rats, indicating augmented autophagic flux. Compared with sham rats, 20-week TAC rats did not show any changes of LC3, cathepsin D, ubiquitin and complement 9 in myocardium detected by immunofluorescent histochemistry. In addition, protein levels of LC3, cathepsin D and p62 in myocardium of TAC rats did not changed. These results reveal the unchanged autophagic flux in cardiomyocytes at middle or late phase of cardiac hypertrophy in TAC rats, implying a balance between inhibition of hypertrophy and activation of pressure load stress on autophagy.

Enhanced N-terminal degradation of troponin I blunts cardiac function responsiveness to isoproterenol in 4-week tail-suspended rats.

The N-terminal extension of cardiac troponin I (cTnI) is important in regulating cardiac function. Although the normal rat myocardium shows some cTnI N-terminal degradation (cTnI-ND), exposure to 4 weeks of tail-suspension markedly increased cTnI-ND. We hypothesized that the increased cTnI-ND in tail-suspended rats may affect cardiac function, particularly during ß-adrenergic (ß-A) stimulation. The increase in cardiac output with isoproterenol (ISO) treatment was smaller in tail-suspended rats compared with controls. Left ventricular end-diastolic pressure was elevated and increases in maximal rates of left ventricular pressure development and relaxation were lower during ISO treatment in tail-suspended rats. Response to ISO, forskolin, DB-cAMP and IBMX was also lower in cardiomyocytes from tail-suspended rats. The increase in shortening and re-lengthening the rates of cardiomyocytes at a maximal dose of ISO, forskolin, DB-cAMP and IBMX treatment was limited in tail-suspended rats. There was no difference in Ca2+ sensitivity of the isometric force between tail-suspended and control rats, although Ca2+ sensitivity was decreased less in tail-suspended rats versus control rats during PKA phosphorylation. There was no difference in PKA protein expression and activation during ISO stimulation between the two groups. Due to the increase in cTnI-ND, ISO-induced phosphorylation of cTnI was reduced in tail-suspended rats. The total phospholamban expression and phosphorylation by ISO was unaltered in tail-suspended rat hearts. These data suggest that enhanced cTnI-ND following 4-week tail-suspension is a major component of the ß-A receptor signaling pathway, depressing cardiac function under ISO stimulation.

[Relationship of S100B protein expression and the pathogenesis of early-onset and late-onset preeclampsia].

OBJECTIVE: To investigate the relationship of S100B protein expression and the pathogenesis of early-onset and late-onset preeclampsia. METHODS: Sixty patients with preeclampsia who received caesarean section at Qingdao Municipal Hospital from October 2010 to September 2011 were enrolled in this study. Thirty cases were early-onset preeclampsia (referred as early-onset preeclampsia group, < 34 weeks), and the other 30 cases were late-onset preeclampsia (referred as late-onset preeclampsia group, ≥ 34 weeks). Thirty women who received caesarean section because of pelvic structural deformities, breech presentation, macrosomia and social factors were included as the control group. The expression of S100B mRNA in the placenta was detected by reverse transcription (RT)-PCR. The expression of S100B protein in the placenta was detected by immunohistochemistry. RESULTS: (1) S100B mRNA was expressed in the trophoblasts of preeclampsia and control groups. The expression of S100B mRNA in early-onset preeclampsia group (0.73 ± 0.11) was significantly higher than the control group (0.58 ± 0.08) and late-onset preeclampsia group (0.64 ± 0.10, P < 0.05). There was no significant difference between late-onset preeclampsia group and the control group (P > 0.05). (2) S100B protein was expressed in the plasma membrane and cytoplasm of the trophoblasts, correlated positively with the brownish yellow and brown particles inside the cells. It was expressed in all the three groups. Immunohistochemistry revealed that the expression of S100B protein in the placenta of early-onset preeclampsia group was 100% (30/30), significantly higher than those of late-onset preeclampsia group and the control group, in which the positive rate were 70% (21/30) and 63% (19/30) respectively (P < 0.05). There was no difference between late-onset preeclampsia group and the control group (P > 0.05). CONCLUSION: Early-onset and late-onset preeclampsia may have different etiology and pathogenesis. S100B may be a factor in the pathogenesis of early-onset preeclampsia.

[Correlative analysis of different HBV genotypes and autoantibodies in hepatitis B patients].

To study the genotypes of hepatitis B virus (HBV) in patients from Chongqing district and determine the prevalence of autoantibodies in these patients. HBV genotyping was carried out by restriction fragment length polymorphism analysis of venous blood serum samples from 252 chronic hepatitis B (CHB) patients and 25 healthy controls. Indirect immunofluorescent assay was used to detect autoantibodies, including antinuclear antibody, anti-mitochondrial antibody, anti-smooth muscle (SM) antibody, and anti-liver and kidney microsomal antibody. Immunospot assay was used to detect anti-ribonucleoprotein/anti-SM antibodies, anti-SS-A antibody, anti-SS-B antibody, anti-scl-70 antibody, and anti-Jo-1 antibody. Correlations between the production of autoantibodies and patient age and sex and various genetypes of HBV were analyzed by the Chi-squared test. The most frequent HBV genotype in CHB patients was B (67.3%), followed by genotype C (32.7%). Genotypes A, D, E, F, G and H were not detected in any of the CHB patients. The positive rate of autoantibodies was higher in the CHB patients than in the healthy group (76.98% vs. 12.00%, X2 = 44.60, P less than 0.05). There was no significant differences in the autoantibodies profiles of CHB patients carrying the B or C genotypes ( X2 = 0.0016, P more than 0.05). The main HBV genotypes in CHB patients in the Chongqing district are B and C. Autoantibodies are prevalent among these CHB patients, and are correlated with patient age and course of liver disease but not HBV genotype or patient sex.

A novel splice site mutation in ANTXR2 (CMG2) gene results in systemic hyalinosis.

Systemic hyalinosis is a rare autosomal recessive inheritance disease characterized by accumulation of amorphous, unidentified hyaline material in skin and other organs, which leads to papulonodular skin lesions, gingival hypertrophy, flexion contractures of the joints, and large subcutaneous tumors. It is composed of 2 allelic syndromes, infantile systemic hyalinosis and juvenile hyaline fibromatosis. Here we describe a patient with juvenile hyaline fibromatosis confirmed by clinical and histopathologic findings, and genetic analysis, which revealed a novel homozygous splice site mutation IVS14+1G→T on exon 14 in anthrax toxin receptor 2 gene.

Synergistic effects between phosphorylation of phospholamban and troponin I promote relaxation at higher heart rate.

We hypothesized that the extent of frequency-dependent acceleration of relaxation (FDAR) would be less than that of isoproterenol-(ISO-)dependent acceleration of relaxation (IDAR) at the same increment of heart rates, and ISO may improve FDAR. Cardiac function and phosphorylation of PLB and cTnI were compared in pacing, ISO treatment, and combined pacing and ISO treatment in isolated working heart. The increase in cardiac output and the degree of relaxation was less in pacing than in ISO treatment at the same increment of heart rates. The increasing stimulation frequency induced more significant relaxant effect in ISO perfusion than that in physiological salt perfusion. The pacing only phosphorylated PLB at Thr17, but ISO induced phosphorylation of cTnI and PLB at Ser16 and Thr17. Those results suggest that the synergistic effects of PLB and cTnI induce higher degree of relaxation which makes a sufficient diastolic filling of the ventricle at higher heart rate.

High glucose alters apoptosis and proliferation in HEK293 cells by inhibition of cloned BK Ca channel.

It has been reported that diabetic vascular dysfunction is associated with impaired function of large conductance Ca(2+) -activated K(+) (BK(Ca) ) channels. However, it is unclear whether impaired BK(Ca) channel directly participates in regulating diabetic vascular remodeling by altering cell growth in response to hyperglycemia. In the present study, we investigated the specific role of BK(Ca) channel in controlling apoptosis and proliferation under high glucose concentration (25 mM). The cDNA encoding the α+ß1 subunit of BK(Ca) channel, hSloα+ß1, was transiently transfected into human embryonic kidney 293 (HEK293) cells. Cloned BK(Ca) currents were recorded by both whole-cell and cell-attached patch clamp techniques. Cell apoptosis was assessed with immunocytochemistry and analysis of fragmented DNA by agarose gel electrophoresis. Cell proliferation was investigated by flow cytometry assays, MTT test, and immunocytochemistry. In addition, the expression of anti-apoptotic protein Bcl-2, intracellular Ca(2+) , and mitochondrial membrane potential (Δψm) were also examined to investigate the possible mechanisms. Our results indicate that inhibition of cloned BK(Ca) channels might be responsible for hyperglycemia-altered apoptosis and proliferation in HEK-hSloα+ß1 cells. However, activation of BK(Ca) channel by NS1619 or Tamoxifen significantly induced apoptosis and suppressed proliferation in HEK-hSloα+ß1 cells under hyperglycemia condition. When rat cerebral smooth muscle cells were cultured in hyperglycemia, similar findings were observed. Moreover, the possible mechanisms underlying the activation of BK(Ca) channel were associated with decreased expression of Bcl-2, elevation of intracellular Ca(2+) , and a concomitant depolarization of Δψm in HEK-hSloα+ß1 cells. In conclusion, cloned BK(Ca) channel directly regulated apoptosis and proliferation of HEK293 cell under hyperglycemia condition.

Nuclear translocation of calpain-2 regulates propensity toward apoptosis in cardiomyocytes of tail-suspended rats.

The compensatory increase in catecholamine release does not reverse orthostatic intolerance after returning from a long-term spaceflight, but it is unclear whether high dose of catecholamine induces cardiac damage. The tail-suspended rat model was used to simulate the effects of weightlessness on the heart. Apoptotic rates in the left ventricular myocardium did not increase in 4-week of tail-suspended rats compared with the synchronous control. On the contrary, isoproterenol (intraperitoneal injection) and 1-day recovery from the 4-week tail-suspension increased apoptotic rates in the myocardium. Propranolol and PD150606 inhibited cardiomyocyte apoptosis in the recovery group. PD150606 and calpain-2 knockdown also blocked isoproterenol-induced cardiomyocyte apoptosis in tail-suspended rats. The activity and nuclear translocation of calpain-2 increased, but the expression of calpain-1, calpain-2, and calpastatin was unchanged in the myocardium of tail-suspended rats. The Ser-16-phosphorylated phospholamban of the nuclear envelope was higher in tail-suspended rats than in the control rats under isoproterenol stimulation. Isoproterenol treatment also induced a large intranuclear Ca(2+) transient of cardiomyocytes in tail-suspended rats. These results suggest that high-dose isoproterenol phosphorylates phospholamban of the nuclear envelope and increases intranuclear Ca(2+) transient. Larger intranuclear Ca(2+) further activates nuclear calpain-2 and hence induces cardiomyocyte apoptosis.

Association of shorter mean telomere length with large artery stiffness in patients with coronary heart disease.

BACKGROUND: Accumulating evidence implicates leukocyte telomere length (LTL) shortening as a potential risk predictor for cardiovascular disease. Arterial stiffness chronicles the cumulative burden of cardiovascular disease risk factors. Therefore, the capacity of LTL to predict arterial stiffness was examined. METHODS: A total of 275 unrelated Chinese males: 163 patients with coronary artery disease (CAD) and 112 healthy controls, 40-73 years of age were included in this study. The relative telomere length of leukocytes was determined by a real-time fluorescence quantitative polymerase chain reaction (PCR). Large artery stiffness was measured with carotid-femoral pulse wave velocity (PWV). RESULTS: The relative telomere length (T/S) ratio was significantly shorter in patients with CAD (0.79 +/- 0.26) than in control subjects (1.08 +/- 0.22) (p<0.001). The correlation between LTL and PWV in patients with CAD was stronger than that in the controls (r= -0.467, r(2)=0.227, p<0.001 for patients with CAD versus r= -0.223; r(2)=0.050; p=0.018 for controls). The log(e)-transformed T/S ratio was inversely correlated with age (r= -0.345; p<0.001), PWV (r= -0.326; p<0.001) and C-reactive protein ( r= -0.133; p=0.027). CONCLUSIONS: The data show an association of leukocyte telomere length shortening with increased arterial stiffness and cardiovascular burden, suggesting that telomere length is a biomarker of large artery elasticity and CAD. Further studies are warranted to study the role of LTL dynamics in the pathogenesis of atherosclerosis.

[Cardiac hypertrophy and changes in contractile function of cardiomyocyte].

To investigate the cellular mechanisms of pressure-overload cardiac hypertrophy transition to heart failure, we observed time course of changes in morphology and contractile function of cardiomyocytes in transverse abdominal aortic constriction (TAC) rats. Since TAC rats suffered higher stress, body weight had a slower growth rate compared with that of synchronous control rats. Therefore, the left ventricular to body weight ratio produced experimental bias to evaluate the degree of cardiac hypertrophy. Length and width of collagenase-isolated cardiomyocyte were directly measured. Length, width and calculated surface area of cardiomyocyte showed a progressive increase in 8-, 16-, and 20-week TAC rats. The increasing rate of surface area in cardiomyocytes was higher at the middle stage of TAC (from the eighth to sixteenth week). Due to the constraint of fibrosis formation, the increasing rate of surface area in cardiomyocytes was slower at the late stage of TAC (from the sixteenth to twentieth week). The sarcomere length of cardiomyocytes was unchanged, whereas sarcomere numbers were significantly increased in 8-, 16-, and 20-week TAC rats. Shortening amplitude of unloaded contraction in single cardiomyocyte was significantly enhanced in 1-week TAC rats, but not altered in 8-week TAC rats compared with that in the synchronous control rats. On the contrary, unloaded shortening amplitude of single cardiomyocyte was significantly reduced in 16- and 20-week TAC rats. The above results suggest that the reduced shortening amplitude may be associated with intrinsic molecular alterations in hypertrophied cardiomyocytes.