Self-organizing behaviors of cardiovascular cells on synthetic nanofiber scaffolds

In tissues and organs, the extracellular matrix (ECM) helps maintain inter- and intracellular architectures that sustain the structure-function relationships defining physiological homeostasis. Combining fiber scaffolds and cells to form engineered tissues is a means of replicating these relationships. Engineered tissues' fiber scaffolds are designed to mimic the topology and chemical composition of the ECM network. Here, we asked how cells found in the heart compare in their propensity to align their cytoskeleton and self-organize in response to topological cues in fibrous scaffolds. We studied cardiomyocytes, valvular interstitial cells, and vascular endothelial cells as they adapted their inter- and intracellular architectures to the extracellular space. We used focused rotary jet spinning to manufacture aligned fibrous scaffolds to mimic the length scale and three-dimensional (3D) nature of the native ECM in the muscular, valvular, and vascular tissues of the heart. The representative cardiovascular cell types were seeded onto fiber scaffolds and infiltrated the fibrous network. We measured different cell types' propensity for cytoskeletal alignment in response to fiber scaffolds with differing levels of anisotropy. The results indicated that valvular interstitial cells on moderately anisotropic substrates have a higher propensity for cytoskeletal alignment than cardiomyocytes and vascular endothelial cells. However, all cell types displayed similar levels of alignment on more extreme (isotropic and highly anisotropic) fiber scaffold organizations. These data suggest that in the hierarchy of signals that dictate the spatiotemporal organization of a tissue, geometric cues within the ECM and cellular networks may homogenize behaviors across cell populations and demographics.

Cellulose Nanofiber-Alginate Biotemplated Cobalt Composite Multifunctional Aerogels for Energy Storage Electrodes

Tunable porous composite materials to control metal and metal oxide functionalization, conductivity, pore structure, electrolyte mass transport, mechanical strength, specific surface area, and magneto-responsiveness are critical for a broad range of energy storage, catalysis, and sensing applications. Biotemplated transition metal composite aerogels present a materials approach to address this need. To demonstrate a solution-based synthesis method to develop cobalt and cobalt oxide aerogels for high surface area multifunctional energy storage electrodes, carboxymethyl cellulose nanofibers (CNF) and alginate biopolymers were mixed to form hydrogels to serve as biotemplates for cobalt nanoparticle formation via the chemical reduction of cobalt salt solutions. The CNF-alginate mixture forms a physically entangled, interpenetrating hydrogel, combining the properties of both biopolymers for monolith shape and pore size control and abundant carboxyl groups that bind metal ions to facilitate biotemplating. The CNF-alginate hydrogels were equilibrated in CaCl2 and CoCl2 salt solutions for hydrogel ionic crosslinking and the prepositioning of transition metal ions, respectively. The salt equilibrated hydrogels were chemically reduced with NaBH4, rinsed, solvent exchanged in ethanol, and supercritically dried with CO2 to form aerogels with a specific surface area of 228 m2/g. The resulting aerogels were pyrolyzed in N2 gas and thermally annealed in air to form Co and Co3O4 porous composite electrodes, respectively. The multifunctional composite aerogel's mechanical, magnetic, and electrochemical functionality was characterized. The coercivity and specific magnetic saturation of the pyrolyzed aerogels were 312 Oe and 114 emu/gCo, respectively. The elastic moduli of the supercritically dried, pyrolyzed, and thermally oxidized aerogels were 0.58, 1.1, and 14.3 MPa, respectively. The electrochemical testing of the pyrolyzed and thermally oxidized aerogels in 1 M KOH resulted in specific capacitances of 650 F/g and 349 F/g, respectively. The rapidly synthesized, low-cost, hydrogel-based synthesis for tunable transition metal multifunctional composite aerogels is envisioned for a wide range of porous metal electrodes to address energy storage, catalysis, and sensing applications.

[Current status and thought of transcatheter mitral edge-to-edge repair in the treatment of hypertrophy cardiomyopathy]

Septal reduction therapies, which include septal myectomy and alcohol septal ablation and so on, are the current treatment strategies for patients with obstructive hypertrophic cardiomyopathy and drug-refractory symptoms. With the deepening of theoretical understanding and the rapid development of interventional therapies, some researchers have tried to perform transcatheter mitral valve edge-to-edge repair to treat high-risk patients with hypertrophic cardiomyopathy, including obstructive and non-obstructive. The reported results are relatively satisfactory, but many urgent problems need to be solved, such as the lack of data on animal experiments and large cohort studies, and the unknown medium- and long-term outcomes. However, transcatheter mitral valve edge-to-edge repair brings new ideas for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. On one hand, it can be used as a monotherapy, on the other hand, it can be combined with novel molecular targeted drug therapy or emerging minimally invasive surgical procedures targeting hypertrophic ventricular septum, which deserves our further attention and exploratory research.

[Safety and efficacy of percutaneous intervention for children with combined congenital heart abnormality solely guided by transthoracic echocardiography]

Objective: To investigate the safety and efficacy of percutaneous intervention of children with combined congenital heart abnormality solely guided by transthoracic echocardiography (TTE) . Methods: From September 2015 to June 2017, 21 children with combined congenital heart abnormality undergoing percutaneous interventional guided by TTE in Fuwai hospital were enrolled in our study, and the clinical data were retrospective analyzed. The atrial septal defect(ASD) closure, ventricular septal defect(VSD) closure, patent ductus arteriosus(PDA) closure or balloon pulmonary valvuloplasty were performed under the guidance of TTE. The procedural effect was evaluated by TTE after operation. The patients were followed up after discharged from the hospital. Results: The age was (37.3±11.6) months, and there were 9 male and 12 female patients. There were 4 cases with ASD and VSD, 6 cases with VSD and PDA, 6 cases with ASD and PDA, 2 cases with VSD and pulmonary stenosis, 3 cases with ASD and pulmonary stenosis. The operations were successfully performed in all patients. No one required extra X ray guidance or open heart surgery. The operation time was (44.6±7.5)min. All patients did not require blood transfusion, inotropic support, and analgesia. There were no complications such as peripheral vascular injury and pericardialeffusion after the operation. The length of hospital stay time was (3.5±0.6) days. All patients were recovered well. The follow-up was (17.6±5.2) months, and post-procedural conduction disturbances, residual shunts, occlude fall off, thrombosis, and new onset of valvular regurgitation were not observed in these patients. Conclusion: Percutaneous interventional of children with combined congenital heart abnormality solely guided by TTE is safe and effective, and the procedure can avoid the potential injuries of X ray and contrast agent.

[Correlation between the parameters of acoustic cardiography and BNP, LVEF and cardiac function grading in patients with chronic heart failure]

Objective: To explore the correlation between the parameters of the new generation of Acoustic Cardiography and brain natriuretic peptide (BNP), left ventricular ejection fraction (LVEF) and cardiac function grading in the diagnosis of heart failure. Methods: One hundred and sixty-eight inpatients, who were hospitalized in Department of Cardiology, Haikou People's Hospital from May 2016 to July 2017, were enrolled as heart failure group, including NYHA class Ⅰ(n=29), NYHA class Ⅱ(n=40), NYHA class Ⅲ(n=64), NYHA class Ⅳ (n=35). And eighty-seven patients with normal cardiac function were selected as healthy control group. The data of the two groups were analyzed after the Acoustic Cardiography test, BNP determination and LVEF examination. Results: The differences in QRS duration, electromechanical activation time (EMAT), EMAT%, systolic dysfunction index (SDI), third heart sound (S3) and other indicators among the groups with different levels of cardiac function were statistically significant (P<0.05). The difference in left ventricular systolic time (LVST) between the cardiac function grade Ⅰ and healthy group was not significant (P>0.05), while the differences among the rest groups were significant. There was a positive correlation between QRS duration, EMAT%, SDI, S3 and BNP (t=9.46, 11.38, 12.14, 9.67, respectively, P<0.05); LVST and BNP were negatively correlated (t=-14.27, P<0.05). There was a negative correlation between QRS duration, EMAT%, SDI, S3 and LVEF (t=11.24, -8.764, -2.393, -0.579, respectively, P<0.05). There was a positive correlation between LVST and LVEF (t=23.48, P<0.05). There was a positive correlation between QRS duration, EMAT%, SDI, S3 and cardiac function grading (β=0.003, 0.234, 0.419, 0.352, respectively, P<0.05). There was a negative correlation between LVST and cardiac function grade (β=-0.021, P<0.05). Conclusion: The parameters of the Acoustic Cardiography test (EMAT%, EMAT, SDI, S3 ) are closely related to BNP, LVEF and cardiac function grading, and can be used as assistant indexes for the diagnosis and evaluation of heart failure.

[Feasibility of device closure for multiple atrial septal defects using 3D printing and ultrasound-guided intervention technique]

Objective: To investigate the feasibility of trans-catheter closure of multiple atrial septal defects (ASD) monitored by trans-thoracic echocardiography (TTE) under the guidance of 3D printing heart model. Methods: Between April and August 2016, a total of 21 patients (8 male and 13 female) with multiple ASD in Fuwai Hospital of Chinese Academy of Medical Sciences underwent CT scan and 3-dimensional echocardiography for heart disease model produced by 3D printing technique. The best occlusion program was determined through the simulation test on the model. Percutaneous device closure of multiple ASD was performed follow the predetermined program guided by TTE. Clinical follow-up including electrocardiogram and TTE was arranged at 1 month after the procedure. Results: The trans-catheter procedure was successful in all 21 patients using a single atrial septal occluder. Mild residual shunt was found in 5 patient in the immediate postoperative period, 3 of them were disappeared during postoperative follow-up. There was no death, vascular damage, arrhythmia, device migration, thromboembolism, valvular dysfunction during the follow-up period. Conclusion: The use of 3D printing heart model provides a useful reference for transcatheter device closure of multiple ASD achieving through ultrasound-guided intervention technique, which appears to be safe and feasible with good outcomes of short-term follow-up.

Isolation and imprinting analysis of the porcine DLX5 gene and its association with carcass traits

Imprinted genes play important roles in mammalian growth and development. However, reports on imprinted genes are limited in livestock. In this study, the complete ORF containing 289 amino acids of the porcine DLX5 gene was obtained. A C-to-T SNP mutation in exon 1 of the DLX5 gene was used to detect imprinting status with an RT-PCR/RFLP test (using HhaI) in eight heterozygous pigs from a population of Large White x Meishan F(1) hybrids. Imprinting analysis showed that the porcine DLX5 gene was maternally expressed in skeletal muscle, fat, lung, spleen, stomach and small intestine, but not imprinted in heart, liver, kidney, uterus, ovary, testicle or pituitary. A PCR-RFLP test was also used to detect the polymorphism in 310 pigs of a Large White x Meishan F(2) resource population. The statistical results showed significant association (P < 0.01) of the genotypes and fat meat percentage, carcass length, bone percentage, 6-7 rib fat thickness, average backfat thickness, thorax-waist fat thickness and buttock fat thickness.

Imprinted status of pleomorphic adenoma gene-like I and paternal expression gene 10 genes in pigs1

Genomic imprinting is theorized to exist in all placental mammals and some marsupials. Imprinted genes play important roles in the regulation of fetal growth, development, and postnatal behavior, but the study of imprinted genes has been limited in livestock. In this study, the polymorphism-based approach was used to detect the expression patterns of the porcine pleomorphic adenoma gene-like I (PLAGL1) and paternal expression gene 10 (PEG10) genes. Single nucleotide polymorphisms in the exons were detected between the Meishan and Large White breeds in the PLAGL1 and PEG10 genes. The polymorphisms were used to determine the monoallelic or biallelic expression with reverse transcription-PCR-RFLP in 44 tissues from 4 heterozygous pigs (based on SNP). Imprinting analysis indicated that the PLAGL1 and PEG10 genes were both paternally expressed in all tissues tested (heart, liver, spleen, lung, kidney, stomach, small intestine, skeletal muscle, fat, uterus, and ovary). Our study showed that the method of identifying polymorphic transcripts with reverse transcription-PCR-RFLP may be beneficial for detecting the imprinting status of some candidate imprinted genes.

Evaluation of 2-deoxy-D-glucose as a chemotherapeutic agent: mechanism of cell death

Nutrient deprivation has been shown to cause cancer cell death. To exploit nutrient deprivation as anti-cancer therapy, we investigated the effects of the anti-metabolite 2-deoxy-D-glucose on breast cancer cells in vitro. This compound has been shown to inhibit glucose metabolism. Treatment of human breast cancer cell lines with 2-deoxy-D-glucose results in cessation of cell growth in a dose dependent manner. Cell viability as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide conversion assay and clonogenic survival are decreased with 2-deoxy-D-glucose treatment indicating that 2-deoxy-D-glucose causes breast cancer cell death. The cell death induced by 2-deoxy-D-glucose was found to be due to apoptosis as demonstrated by induction of caspase 3 activity and cleavage of poly (ADP-ribose) polymerase. Breast cancer cells treated with 2-deoxy-D-glucose express higher levels of Glut1 transporter protein as measured by Western blot analysis and have increased glucose uptake compared to non-treated breast cancer cells. From these results we conclude that 2-deoxy-D-glucose treatment causes death in human breast cancer cell lines by the activation of the apoptotic pathway. Our data suggest that breast cancer cells treated with 2-deoxy-D-glucose accelerate their own demise by initially expressing high levels of glucose transporter protein, which allows increased uptake of 2-deoxy-D-glucose, and subsequent induction of cell death. These data support the targeting of glucose metabolism as a site for chemotherapeutic intervention by agents such as 2-deoxy-D-glucose.

Association and activation of fructose 1,6-bisphosphase during unfolding and refolding: spectroscopic and enzymatic studies

Fructose 1,6-biphosphase is a well-characterized oligomer enzyme, and many effectors allosterically control its activity. In this report, we compared the activity, allosteric properties, and conformational changes in its denaturant-induced unfolding processes. In addition, a trpytophan residue has been introduced into the interface between the C1 and C2 subunits to investigate conformational changes during unfolding. Results show that the denaturation curves of WT FruP2ase detected by various methods do not agree, and the dissociation occurs first with a monomeric form existing around 0.4 M GdmCl as shown by gel filtration. The dissociation of all mutants is accompanied by changes in fluorescence intensity. The results suggest that the unfolding of FruP2ase is a complicated, multiphase process. The activation of FruP2ase by GdmCl at low concentrations can be interpreted as a consequence of the effect of monovalent cation. In the refolding experiments, it is found that Mg2+ is not only essential for enzyme activity, but also can assist the enzyme in refolding and association by preventing the formation of aggregates.

Molecular cloning, expression and purification of muscle fructose-1,6-bisphosphatase from Zaocys dhumnades: the role of the N-terminal sequence in AMP activation at alkaline pH

An open reading frame (ORF) of snake muscle fructose-1,6-bisphosphatase (Fru-1,6-P2ase) was obtained by the RT-PCR method with degenerate primers, followed by RACE-PCR. The cDNA of Fru-1,6-P2ase, encoding 340 amino acids, is highly homologous to that of mammalian species, especially human muscle, with a few exceptions. Kinetic parameters of the purified recombinant enzyme, including inhibition behavior by AMP, were identical to that of the tissue form. Replacement of the N-terminal sequence of this enzyme by the corresponding region of rat liver Fru-1,6-P2ase shows that the activity was fully retained in the chimeric enzyme. The inhibition constant (Ki) of AMP at pH 7.5, however, increases sharply from 0.85 microM (wild-type) to 1.2 mM (chimeric enzyme). AMP binding is mainly located in the N-terminal region, and the allosteric inhibition was shown not to be merely determined by the backbone of this region. The fact that the chimeric enzyme could be activated at alkaline pH by AMP indicated that the AMP activation requires the global structure beyond the area.