Safety and Effectiveness Outcomes of a Novel Automated Titanium Suture Fastener Device Applied for Heart Valve Surgery in an Ovine Model.

OBJECTIVE: This study was designed to evaluate the operability, effectiveness, and safety of the automated titanium suture fastener in a preclinical ovine model in comparison with manual tying in a mitral valve annuloplasty ring implantation surgery. METHODS: Eighteen adult Small-tailed Han sheep were prepared for the surgery of mitral valve annuloplasty ring implantation through lateral thoracotomy under cardiopulmonary bypass (CBP). A total of 12 stitches were performed to secure an annuloplasty ring, with 6 stitches done with the automated fastener and the other 6 by manual tying. The knotting time for the automated fastener or manual tying was recorded, respectively. The firmness of knots, mitral valve integrity, biocompatibility, thrombosis, local reactions, and other aspects were also compared at follow-up time (Days 30, 60, 90, and 180). RESULTS: Of the 18 sheep, 16 survived to the designated endpoints and were enrolled for further analysis. Compared with the control group, the knotting time was significantly reduced with the automated fastener (p < 0.01). All the annuloplasty rings were tightly secured by 6 fastener clips and 6 hand-made knots without any disengagement or displacement. All the mitral valves were intact without any defect, stenosis, prolapse, valve insufficiency, or perforation. Endothelialization was comparable between the two groups by Day 60. Small red thrombi formed at the thread end of the suture in both groups. No thrombus was found on the surface of the titanium clip. All the thrombi were within the acceptable range for the antithrombotic property. Thrombosis showed no significant difference by Day 60. No significant differences in the inflammatory response and pathological lesions were observed by Day 60. One case of diffuse renal infarction (area ratio = 20%) and 1 case of small focal renal infarction (area ratio < 5%) were caused by thromboembolism. CONCLUSIONS: The automated fastener significantly shortened the procedure time of tying knots for the implantation of the annuloplasty ring in the ovine model, with comparable safety and effectiveness as manual tying.

Multiwalled Carbon Nanotubes Inhibit Steroidogenesis by Disrupting Steroidogenic Acute Regulatory Protein Expression and Redox Status.

Ovarian granulosa cells play crucial roles in the processes of follicle development, ovulation, luteinization and steroid hormone secretion or steroidogenesis. In this study, we used preovulatory rat granulosa cells to investigate the effects of multiwall carbon nanotubes on ovarian endocrine function, especially in regulating progesterone secretion, steroidogenic acute regulatory protein, as well as the potential mechanisms. By using cytotoxicity assays, radioimmunoassay, western blotting and fluorescence quantitative analysis and imaging methods, multiwall carbon nanotubes were found to inhibit the progesterone secretion of preovulatory ovarian granulosa cells by inhibiting the steroidogenic acute regulatory protein expression, and the influence could be restored after the removal of multiwall carbon nanotubes. The underlying mechanisms were related to the cytotoxicity, oxidative stress and mitochondria damages due to the MWCNTs. There were no obvious differences shown due to the distinct tube lengths. Both long and short MWCNTs share the same trends in all the above assays. Our findings provide important insights to the regulatory effects of multiwalled carbon nanotubes on granulosa cell steroidogenesis and subsequent safety evaluation of nanomaterials on reproductive toxicity.

Glutamine protects cardiomyocytes from hypoxia/reoxygenation injury under high glucose conditions through inhibition of the transforming growth factor-ß1-Smad3 pathway.

Activation of transforming growth factor-ß1 (TGF-ß1)-Smad3 pathway aggravates myocardial ischemia/reperfusion injury (IRI). We previously showed that glutamine (Gln) protects cardiomyocytes from hypoxia/reoxygenation (H/R) injury under high glucose (HG) conditions. The aim of this study was to investigate whether Gln exerts its protective effect in H/R via inhibiting TGF-ß1-Smad3 pathway. In vitro, H9c2 rat cardiomyocytes were treated with Gln with HG (33 mM) and/or H/R. We also performed in vivo experiments in which we treated normal and diabetic rats with Gln or solvent control following IRI. We assessed protein levels of TGF-ß1, total Smad3, phosphorylated (p)-Smad3 and cleaved caspase-3 in H9c2 cells and rat myocardium by Western blotting. H9c2 cells treated with HG + H/R exhibited high apoptosis rates, as well as a highly activated TGF-ß1-Smad3 pathway. TGF-ß1 receptor inhibitor (SB431542) or Smad3 inhibitor (SIS3) reduced HG + H/R induced apoptosis. Similarly, Gln supplementation alleviated apoptosis and decreased p-Smad3 levels. However, Gln's protective effect was significantly weakened by TGF-ß1. Diabetic rats treated with Gln had improved hemodynamics, smaller infarct size after IRI, and a significant decrease in TGF-ß1-Smad3 pathway activation. We conclude that Gln inhibits HG + H/R induced activation of the TGF-ß1-Smad3 pathway and decreases cell apoptosis in cardiomyocytes.

Dexamethasone altered steroidogenesis and changed redox status of granulosa cells.

Glucocorticoids have been widely used in clinical application for anti-inflammatory and immunosuppressive function. Previous study reported that glucocorticoids adversely affect the reproductive system and can directly act on ovary. Here, we found that progesterone production induced by dexamethasone requiring activation of caspase-3 which may mediate differentiation and apoptosis of granulosa cells. Further study displayed that cellular glutathione level was increased and reactive oxygen species was decreased accompanied with unchanged mitochondrial membrane potential which may contribute to the maintenance of steroidogenesis in granulosa cells treated with dexamethasone. Dexamethasone also augmented the level of anti-Müllerian hormone secreted by preovulatory granulosa cells which indicated that dexamethasone may promote preantral follicles development.

Knockdown of p66Shc by siRNA injection rescues arsenite-induced developmental retardation in mouse preimplantation embryos.

Two-cell arrest plays a principal role in the elevated levels of embryo loss during the first week of development in mouse. Previously, we have shown that arsenic can apparently induce 2-cell arrest in mouse preimplantation embryo and the expression of oxidative stress adaptor protein p66(Shc) is up-regulated in this process. In the present study, we demonstrated that microinjection of p66(Shc) siRNA into the pronucleus of zygotes resulted in a markedly decrease in both mRNA and protein levels of p66(Shc). The arsenite-induced 2-cell arrests, along with a reduction in the levels of reactive oxygen species (ROS), were significantly inhibited and the number of embryos developing to morula stage concurrently increased upon p66(shc) siRNA microinjection. These findings indicate that knockdown of p66(shc) improves the developmental competence of arsenite-exposed embryos in vitro by increasing the resistance to oxidative stress. In addition, we highlight the utility of single-embryo analysis in preimplantation embryos.

Role of spastin and protrudin in neurite outgrowth.

Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder characterized by retrograde axonal degeneration that primarily affects long spinal neurons. The gene encoding spastin has a well-established association with HSP, and protrudin is a known binding partner of spastin. Here, we demonstrate that the N-terminal domain of protrudin mediates the interaction with spastin, which is responsible for neurite outgrowth. We show that spastin promotes protrudin-dependent neurite outgrowth in PC12 cells. To further confirm these physiological functions in vivo, we microinjected zebrafish embryos with various protrudin/spastin mRNA and morpholinos. The results suggest that the spinal cord motor neuron axon outgrowth of zebrafish is regulated by the interaction between spastin and protrudin. In addition, the putative HSP-associated protrudinG191V mutation was shown to alter the subcellular distribution and impair the yolk sac extension of zebrafish, but without significant defects in neurite outgrowth both in PC12 cells and zebrafish. Taken together, our findings indicate that protrudin interacts with spastin and induces axon formation through its N-terminal domain. Moreover, protrudin and spastin may work together to play an indispensable role in motor axon outgrowth.

Arsenic induced progesterone production in a caspase-3-dependent manner and changed redox status in preovulatory granulosa cells.

Arsenic contamination is a principal environmental health threat throughout the world. However, little is known about the effect of arsenic on steroidogenesis in granulosa cells (GCs). We found that the treatment of preovulatory GCs with arsenite stimulated progesterone production. A significant increase in serum level of progesterone was observed in female Sprague-Dawley rats following arsenite treatment at a dose of 10 mg/L/rat/day for 7 days. Further experiments demonstrated that arsenite treatment did not change the level of intracellular cyclic AMP (cAMP) or phosphorylated ERK1/2 in preovulatory GCs; however, progesterone production was significantly decreased when cAMP-dependent protein kinase (PKA) or ERK1/2 pathway was inhibited. This implied that the effect of arsenite on progesterone production may require cAMP/PKA and ERK1/2 signaling but not depend on them. Furthermore, we found that arsenite decreased intracellular reactive oxygen species (ROS) but increased the antioxidant glutathione (GSH) levels and mitochondrial membrane potential (ΔΨm) in parallel to the changes in progesterone production. Progesterone antagonist blocked the arsenic-stimulated increase of GSH levels. Arsenite treatment induced caspase-3 activation, although no apoptosis was observed. Inhibition of caspase-3 activity significantly decreased progesterone production stimulated by arsenite or follicle-stimulating hormone (FSH). GSH depletion with buthionine sulfoximine led to cell apoptosis in response to arsenite treatment. Collectively, this study demonstrated for the first time that arsenite stimulates progesterone production through cleaved/active caspase-3-dependent pathway, and the increase of GSH level promoted by progesterone production may protect GCs against apoptosis and maintain the steroidogenesis of GCs in response to arsenite treatment.

Follicle-stimulating hormone regulation of microRNA expression on progesterone production in cultured rat granulosa cells.

MicroRNAs (miRNAs) regulate gene expression post-transcriptionally by interacting with the 3' untranslated regions of their target mRNAs. Previously, miRNAs have been shown to regulate genes involved in cell growth, apoptosis, and differentiation, but their role in ovarian granulosa cell follicle-stimulating hormone (FSH)-stimulated steroidogenesis is unclear. Here we show that expression of 31 miRNAs is altered during FSH-mediated progesterone secretion of cultured granulosa cells. Specifically, 12 h after FSH treatment, miRNAs mir-29a and mir-30d were significantly down-regulated. However, their expression increased after 48 h. Bioinformatic analysis used to predict potential targets of mir-29a and mir-30d revealed a wide array of potential mRNA target genes, including those encoding genes involved in multiple signaling pathways. Taken together, our results pointed to a novel mechanism for the pleiotropic effects of FSH.