Rat Inferior Vena Cava Research Articles

Baicalin promotes migration and angiogenesis of endothelial progenitor cells but impedes thrombus formation via SIRT1/NF-κB signaling in a rat model of deep vein thrombosis.

Deep vein thrombosis (DVT) is the third most prevalent vascular disease worldwide, seriously threatening human health. Baicalin, a flavonoid isolated from the roots of Scutellaria baicalensis, has been identified to play a crucial role in various vascular diseases. The study aimed to explore the efficacy and underlying mechanisms of baicalin in DVT. Endothelial progenitor cells (EPCs) were differentiated from peripheral blood mononuclear cells isolated from rat bone marrow. Dil-ac-LDL/FITC-UEA-1 double staining and flow cytometry analysis were conducted for the identification of EPCs. The angiogenesis and migration of EPCs in vitro were tested by a tube formation assay and Transwell assay, respectively. DVT rat models were established by stenosis of the inferior vena cava (IVC). After the euthanasia of rats, thrombi in the IVC were collected and weighed, and histological alterations in IVC tissue were measured by H&E staining. The protein levels of SIRT1, p-P65, and p65 in rat IVC tissues were quantified via western blotting. EPCs used in this study displayed a spindle-like shape and were positive for endothelial cell-specific markers, suggesting the phenotypic characteristics of EPCs. Baicalin enhanced the migratory and angiogenetic abilities of EPCs in vitro. For in vivo experiments, baicalin reduced thrombus weight and mitigated DVT formation in model rats. Moreover, baicalin activated SIRT but repressed NF-κB signaling in IVC tissues of DVT rats. Baicalin facilitates migration and angiogenesis of EPCs but impedes thrombus formation via regulation of SIRT1/NF-κB signaling in DVT model rats.

Abstract 2092: Ultrasound And Histology Protocol For Characterization Of Venous Stents Effect In Deep Veins In Vivo

Background: Deep venous stenting is a common strategy to treat deep vein thrombosis (DVT) decreasing future symptoms and complications. We propose a histopathological characterization of stents deployed in the inferior vena cava of rats and demonstrate how it correlates with ultrasound evaluation. Methods: Sprague Dawley rats (643±62g) were anesthetized (isoflurane). IVC diameter was measured by ultrasound on B mode. Through a midline laparotomy, infrarenal IVC side branches were ligated, posterior venous branches cauterized, micro-clips temporarily placed, and a U-stich is placed in the IVC. Using retrograde canulation of the IVC a sharpened guidewire with a stent sheath backloaded is inserted through the U-stich. The stent sheath is advanced with enough running room to deploy the venous self-expanding stent. After removal, U-stitch was tightened for hemostasis. No anticoagulation was used. Venous flow and patency were measured using a color/pulsed-wave Doppler 10-mHz probe post-procedure (PO) and 24 hours after (POD1). Vein wall thickness (VWT), in-stent-restenosis (ISR), and residual thrombosis percentage were quantified using trichrome staining at 7-, 14-, and 21-days. Results: Complete stent patency was observed in 50% of animals, partial patency in 15%, and obstruction in 35% after insertion. Table I. Recanalization at 1-day improved flow was observed in 41% of obstructed or partially patent stents. ISR was 6.2±3.8% of the luminal stent area (LSA), residual thrombosis in 29.9±23%, VWT mean 80±13.5 μm, no statistical differences found between timepoints. Figure 1. Conclusion: Characterization and follow-up of deep vein stents can be achieved by ultrasound and histology. This viable animal model can identify human pathological stent processes as early thrombosis, resolution, recanalization, and ISR. This model can reduce costs for feasibility studies to test novel stents and simulate real-life patency outcomes at multiple time points.

Silver Ion Decreases Foreign Body Reaction and Venous Neointimal Hyperplasia through the Inhibition of Interleukin-33 Expression

Introduction: Vascular prosthetic grafts are widely used in vascular surgery; however, graft infection remains a major concern. Silver-coated vascular grafts have demonstrated anti-infection properties in clinical settings; however, whether the silver irons influence foreign body reaction or neointimal hyperplasia remains unclear. Methods: Sodium alginate and hyaluronic acid (SA/HA) hydrogel patches loaded with rhodamine, with or without silver, were fabricated. Patches were implanted in the subcutaneous or abdominal cavity and inferior vena cava of rats. Samples were harvested on day 14 and examined via immunohistochemical and immunofluorescence analyses. Results: Silver hydrogel was found to decrease the foreign body reaction; after subcutaneous and abdominal cavity implantation in rats, the capsule was found to be thinner in the silver hydrogel group than in the control hydrogel group. The silver hydrogel group had fewer CD68-positive cells and proliferating cell nuclear antigen and interleukin-33 (IL-33) dual-positive cells than the control hydrogel group. Additionally, the silver hydrogel patch reduced the neointimal thickness after patch venoplasty in rats, and the number of IL-33- and IL-1β-positive cells was lower than that in the control patch. Conclusion: Silver-loaded SA/HA hydrogel patches decreased the foreign body reaction and venous neointimal hyperplasia in rats by the inhibition of IL-33 expression.

Delivery of rivaroxaban and chitosan rapamycin microparticle with dual antithrombosis and antiproliferation functions inhibits venous neointimal hyperplasia

Neointimal hyperplasia is a complex process after vascular interventions, acute platelet deposition and smooth muscle cell proliferation both contributed to this process. There are still no perfect solutions to solve this problem. Rivaroxaban is a novel anticoagulant that has been widely used in clinic, it has a good pharmacological effects both in vivo and in vitro. Chitosan microparticle rapamycin (MP-rapa) was fabricated, interspaces of polyglycolic acid (PGA) scaffold were used as a reservoir of MP-rapa, and the scaffold was coated with hyaluronic acid rivaroxaban (MP-rapa-riva). Scanning electronic microscopy (SEM) photographs were taken and water contact angles were measured, rat inferior vena cava (IVC) patch venoplasty model was used; patches were harvested at day 14 and examined by immunohistochemistry and immunofluorescence. SEM photographs showed the microparticles rapamycin were inside the interspace of the scaffold, hyaluronic acid rivaroxaban was also successfully coated onto the surface of the scaffold. There was a thinner neointima, fewer proliferating cell nuclear antigen (PCNA) positive cells, fewer macrophages in the MP-rapa and MP-rapa-riva grafts compared to the control PGA graft. The result showed that this scaffold with dual anticoagulation and antiproliferation functions can effectively inhibit venous neointimal hyperplasia, although this is an animal experiment, it showed promising potential clinical application in the future.

Antithrombotic Activity of an Indolinone Derivative – a Soluble Guanylate Cyclase Stimulator

Introduction . The article presents the results of studying the antithrombotic activity of a novel drug, a soluble guanylate cyclase stimulator (codename – GRS), in experimental models of arterial and venous thrombosis and thromboembolism. Aim . Study the antithrombotic action of GRS compound in comparison with clopidogrel and rivaroxaban in the following models: arterial thrombosis induced by iron chloride application to carotid artery wall in rats; thromboembolism induced by intravenous administration of thrombin solution in mice; venous thrombosis induced by the ligature of inferior vena cava in rats. Materials and methods . Arterial thrombosis was modelled in rats by applying a pad soaked in iron chloride (FeCl 3 ) to the carotid artery, GRS compound was administered orally in median effective dose of 10 mg/kg once 3 hours before pad application. Blood flow in carotid arteries and blood clot mass were registered. Thromboembolism was induced in mice by intravenous administration of thrombin solution, GRS in dose 10 mg/kg or the reference drug clopidogrel were administered once orally daily for 3 days. Animal mortality, survival time and blood clot size were registered. Venous thrombosis was induced in rats by the ligature of inferior vena cava below renal veins, GRS in dose 10 mg/kg, reference drug rivaroxaban in 5 mg/kg dose or their combination in these doses were administered once orally 1 hour before vein ligature. The mass of dry and wet blood clots was registered. Results and discussion . In arterial thrombosis model GRS compound in 10 mg/kg, administered 3 hours before iron chloride application, increased the time to blood flow cessation in the carotid artery by 35 % and reduced the frequency of complete artery occlusion by 2 times compared to the control group ( р < 0.05). 60 min after arterial thrombosis modelling complete occlusion was observed in 28 % of animals in GRS group and in 75 % of control animals, while after 24 hours the occlusion was observed in 14 % of animals in GRS group and in 50 % of control group animals ( p < 0.05). In thrombin-induced thromboembolism model in mice GRS did not reduce the size of blood clots in pulmonary vessels, while clopidogrel reduced it by 48 %. In GRS group 80 % of animals died of thrombosis, compared to 30 % in clopidogrel group and 90 % in the control group. In ligature-induced venous thrombosis in rats GRS after single oral administration reduced the mass of dry blood clot, being as potent as rivaroxaban. Combined administration of GRS and rivaroxaban did not enhance their antithrombotic action. Conclusion . GRS after single oral administration in 10 mg/kg dose had potent antithrombotic action in models of arterial and venous thrombosis in rats, while not preventing pulmonary vessel thrombosis in mice after thrombin administration. Therapeutic action of GRS in experimental venous thrombosis was as potent as that of rivaroxaban. Antithrombotic action of GRS compound results not only from its antiplatelet action, but also from the alleviation of endothelial dysfunction in arteries and veins.

A three-layered hydrogel patch with hierarchy releasing of PLGA nanoparticle drugs decrease neointimal hyperplasia

Hydrogel is a nature scaffold that can degraded in animal body and can be used as a drug delivery system, we hypothesized that patch made of three layers of hydrogel with different PLGA nanoparticle drugs (bio-patch) can be used to decrease venous neointimal hyperplasia. Rat inferior vena cava (IVC) patch venoplasty model was used. Samples from rat IVC direct suture (DS), decellularized thoracic artery patch (TA) venoplasty and bovine pericardial patch (BPP) venoplasty were examined at day 14 after implantation. Sodium alginate and hyaluronic acid (SA/HA) hydrogel was used, three layers hydrogel patch (control) and three layers hydrogel patch with PLGA nanoparticle drugs (bio-patch) were used in rat IVC venoplasty. Patches were harvested at day 14 and analyzed. In rats, TA and BPP patch showed a thicker neointima and adventitia compared to the DS, there were larger numbers of CD68 and PCNA positive cells in both groups. The control hydrogel patch showed much thinner neointima and adventitia compared to TA and BPP patches. In both of the neointima and peri-patch area, bio-patch showed significantly fewer smooth muscle cells, fewer CD68, fewer PCNA positive cells, fewer collagen-1 positive cells, fewer p-smad2 positive cells, fewer TNF-α positive cells compared to control hydrogel patch. Bio-patch made of hydrogel and PLGA nanoparticle drugs showed a thinner neointimal thickness, and is biocompatible to the animal body. These results showed the potential application of hydrogel patch in vascular surgery.

Downregulation of microRNA-200c-3p alleviates the aggravation of venous thromboembolism by targeting serpin family C member 1

ABSTRACT Venous thromboembolism (VTE) is the third most prevalent cardiovascular complication. Increasing studies have demonstrated that some microRNAs (miRNAs) are aberrantly expressed in VTE and play crucial roles in mediating the development of VTE. Therefore, our study intends to explore the detailed function and molecular mechanism of miR-200c-3p in VTE progression. In our research, VTE rat models were first established via inferior vena cava (IVC) ligation and the time-dependent effects of IVC ligation on thrombus formation were discovered. The results of reverse transcription quantitative polymerase-chain reaction (RT-qPCR) and western blotting showed that serpin family C member 1 (SERPINC1) was downregulated in VTE rat models and showed an inverse correlation with thrombus load. MiRNA target prediction tools and luciferase reporter assay confirmed SERPINC1 as a target for miR-200c-3p. VTE rats were injected with miR-200c-3p inhibitor for 24 h to investigate whether miR-200c-3p knockdown influences thrombus formation in vivo. Histological examination through hematoxylin-eosin staining revealed that miR-200c-3p downregulation markedly inhibited the formation of thrombus in IVC of rats. Additionally, miR-200c-3p was upregulated while SERPINC1 was downregulated in serum and inferior vena cava of VTE rats as well as in plasma of patients with VTE. Linear regression analysis demonstrated that miR-200c-3p expression was negatively correlated to SERPINC1 expression in VTE rats and patients with VTE. Our study determines the previously unelucidated function of miR-200c-3p in VTE, which might provide a potential novel insight for the treatment of VTE.

A Novel Plant Leaf Patch Absorbed With IL-33 Antibody Decreases Venous Neointimal hyperplasia.

Introduction: We recently showed that a decellularized leaf scaffold can be loaded with polylactic-co-glycolic acid (PLGA)-based rapamycin nanoparticles, this leaf patch can then inhibit venous neointimal hyperplasia in a rat inferior vena cava (IVC) venoplasty model. IL-33 plays a role in the neointimal formation after vascular injury. We hypothesized that plant leaves can absorb therapeutic drug solution and can be used as a patch with drug delivery capability, and plant leaves absorbed with IL-33 antibody can decrease venous neointimal hyperplasia in the rat IVC venoplasty model. Method: A human spiral saphenous vein (SVG) graft implanted in the popliteal vein was harvested from a patient with trauma and analyzed by immunofluorescence. Male Sprague-Dawley rats (aged 6–8 weeks) were used to create the IVC patch venoplasty model. Plant leaves absorbed with rhodamine, distilled water (control), rapamycin, IL-33, and IL-33 antibody were cut into patches (3 × 1.5 mm2) and implanted into the rat IVC. Patches were explanted at day 14 for analysis. Result: At day 14, in the patch absorbed with rhodamine group, immunofluorescence showed rhodamine fluorescence in the neointima, inside the patch, and in the adventitia. There was a significantly thinner neointima in the plant patch absorbed with rapamycin (p = 0.0231) compared to the patch absorbed with distilled water. There was a significantly large number of IL-33 (p = 0.006) and IL-1β (p = 0.012) positive cells in the human SVG neointima compared to the human great saphenous vein. In rats, there was a significantly thinner neointima, a smaller number of IL-33 (p = 0.0006) and IL-1β (p = 0.0008) positive cells in the IL-33 antibody-absorbed patch group compared to the IL-33-absorbed patch group. Conclusion: We found that the natural absorption capability of plant leaves means they can absorb drug solution efficiently and can also be used as a novel drug delivery system and venous patch. IL-33 plays a role in venous neointimal hyperplasia both in humans and rats; neutralization of IL-33 by IL-33 antibody can be a therapeutic method to decrease venous neointimal hyperplasia.

Thrombolytic and anticoagulant effects of a recombinant staphylokinase-hirudin fusion protein

A pure recombinant staphylokinase-hirudin fusion protein (SFH) was obtained by recombinant genetic engineering and purification techniques. The thrombolytic and anticoagulant activities of SFH were investigated using in vitro coagulation models and chromogenic assays. The results showed that intact SFH had targeted thrombolytic activity, and gained anticoagulant activity when cleaved by FXa. In addition, we investigated the pharmacodynamics of SFH in vivo using a variety of animal models, including a rat inferior vena cava thrombosis model, a rat coronary thrombosis model, a rabbit carotid artery thrombosis model and a canine coronary thrombosis model. We found that SFH had an obvious thrombolytic effect and could prevent and reduce re-embolization after thrombolysis and reduce the serious bleeding side effects caused by the combination of thrombolytic and anticoagulant drugs. The results suggest that SFH can be used for thrombolytic therapy in thromboembolic diseases.

Programmed death-1 mediates venous neointimal hyperplasia in humans and rats

Venous neointimal hyperplasia can be a problem after vein interventions. We hypothesized that inhibiting programmed death-1 (PD-1) can decrease venous neointimal hyperplasia in a rat inferior vena cava (IVC) patch venoplasty model. The rats were divided into four groups: the control group was only decellularized without other special treatment; the PD-1 group was injected with a single dose of humanized PD-1 antibody (4 mg/kg); the PD-1 antibody coated patches group; the BMS-1 (a PD-1 small molecular inhibitor) coated patches group (PD-1 inhibitor-1). Patches were implanted to the rat IVC and harvested on day 14 and analyzed. Immunohistochemical analysis showed PD-1-positive cells in the neointima in the human samples. There was high protein expression of PD-1 in the neointima in the rat IVC venoplasty model. PD-1 antibody injection can significantly decrease neointimal thickness (p < 0.0001). PD-1 antibody or BMS-1 was successfully conjugated to the decellularized rat thoracic artery patch by hyaluronic acid with altered morphology and reduced the water contact angle (WCA). Patches coated with humanized PD-1 antibody or BMS-1 both can also decrease neointimal hyperplasia and inflammatory cells infiltration. PD-1-positive cells are present in venous neointima in both human and rat samples. Inhibition of the PD-1 pathway may be a promising therapeutic strategy to inhibit venous neointimal hyperplasia.

Application of the Tissue-Engineered Plant Scaffold as a Vascular Patch.

Tissue-engineered plant scaffolds have shown promising applications in in vitro studies. To assess the applicability of natural plant scaffolds as vascular patches, we tested decellularized leaf and onion cellulose in a rat inferior vena cava patch venoplasty model. The leaf was decellularized, and the scaffold was loaded with polylactic-co-glycolic acid (PLGA)-based rapamycin nanoparticles (nanoparticles). Nanoparticle-perfused leaves showed decreased neointimal thickness after implantation on day 14; there were also fewer CD68-positive cells and PCNA-positive cells in the neointima in the nanoparticle-perfused patches than in the control patches. Onion cellulose was decellularized, coated with rapamycin nanoparticles, and implanted in the rat; the nanoparticle-coated onion cellulose patches also showed decreased neointimal thickness. These data show that natural plant-based scaffolds may be used as novel scaffolds for tissue-engineered vascular patches. However, further modifications are needed to enhance patch strength for artery implantations.

A polymer-based systemic hemostatic agent.

Uncontrolled noncompressible hemorrhage is a major cause of mortality following traumatic injuries in civilian and military populations. An injectable hemostat for point-of-care treatment of noncompressible hemorrhage represents an urgent medical need. Here, we describe an injectable hemostatic agent via polymer peptide interfusion (HAPPI), a hyaluronic acid conjugate with a collagen-binding peptide and a von Willebrand factor-binding peptide. HAPPI exhibited selective binding to activated platelets and promoted their accumulation at the wound site in vitro. In vivo studies in mouse tail vein laceration model demonstrated a reduction of >97% in both bleeding time and blood loss. A 284% improvement in the survival time was observed in the rat inferior vena cava traumatic model. Lyophilized HAPPI could be stably stored at room temperature for several months and reconstituted during therapeutic intervention. HAPPI provides a potentially clinically translatable intravenous hemostat.

Hyaluronic acid-heparin conjugated decellularized human great saphenous vein patches decrease neointimal thickness.

Although the science of implantable materials has advanced therapeutic options in vascular surgery, graft failure is still a problem in need of a durable solution. With the development of coating and decellularization techniques, coated prosthetic grafts have become an option; however, whether decellularized human saphenous vein can be conjugated and implanted is not known. Human great saphenous vein (GSV) was harvested and decellularized and hyaluronic acid (HA)-heparin was conjugated to the GSV; water contact angles (WCA), morphology, and sulfur element change were measured before and after heparin bonding. GSV patches were implanted into the rat inferior vena cava and aorta; patches were harvested (Day 14) and analyzed. HA-heparin was successfully conjugated to the decellularized human GSV with altered morphology and reduced WCA. The HA-heparin coated decellularized GSV patch was anti-thrombotic in vitro, and significantly decreased neointimal thickness both in patch venoplasty and angioplasty in a rat model. Both CD90 and nestin positive cells participated in neointima formation. These data show that HA-heparin coated human GSV patches decrease neointimal thickness when used both in venoplasty and arterioplasty. Tissue engineered decellularized human GSV is a promising vascular prosthesis.

Sulodexide Improves Contraction and Decreases Matrix Metalloproteinase-2 and -9 in Veins Under Prolonged Stretch.

High pressure in the lower-limb veins is often associated with chronic venous insufficiency and varicose veins (VVs), making it important to search for the mechanisms and agents that control venous function. We have shown that protracted increases in venous stretch/wall tension reduce vein contraction and augment matrix metalloproteinase (MMP)-2 and -9. Also, MMP-2 and MMP-9 promote venodilation, a hallmark of VVs. Sulodexide (SDX) is a blend of glycosaminoglycans with efficient profibrinolysis and antithrombosis activities, but its actions on vein function and the mechanisms involved are unclear. We tested the hypothesis that SDX enhances venous contractile response by decreasing MMP expression/activity in veins subjected to protracted stretch. Rat inferior vena cava (IVC) rings were treated with SDX (0.001-1 mg/mL) or vehicle, equilibrated under control 0.5-g resting tension or protracted 2-g stretch for 18 hours, and the contractile response to 96-mM KCl and phenylephrine (Phe) in SDX-treated and nontreated veins was recorded. In IVC rings under control 0.5-g resting tension, SDX caused dose-dependent contraction, 96-mM KCl caused marked contraction (176-mg/mg tissue), and Phe caused dose-dependent contraction with a maximum (56-mg/mg tissue) at 10 M. In IVC subjected to protracted 2-g stretch, 96-mM KCl-induced contraction was reduced to 112 mg/mg and maximal Phe-induced contraction was decreased to 23 mg/mg. In IVC subjected to protracted 2-g stretch plus SDX, 96-mM KCl-induced contraction was restored to 228 mg/mg and maximal Phe-induced contraction was improved to 115 mg/mg. Gelatin zymography and Western blots revealed increases in MMP-2 and MMP-9 levels/gelatinolytic activity in veins subjected to protracted 2-g stretch and reversal to control levels in veins subjected to 2-g stretch plus SDX. Thus, SDX improves vein function and augments the contractile response in veins subjected to protracted stretch. The SDX-induced improvement of contraction and restoration of vein function appear to involve decreases in MMP-2 and MMP-9 and may contribute to the benefits of SDX in chronic venous insufficiency and VVs.

Autologous tissue patches acquire vascular identity depending on the environment.

Vascular identity is genetically determined, but can be altered during surgical procedures. We hypothesized that the environment of the procedure critically alters the identity of autologous tissue patches implanted into the arterial or venous environment. Autologous jugular vein or carotid artery was used as a patch to repair a rat aorta or inferior vena cava. In the aortic environment patches contained neointimal cells that were CD34/Ephrin-B2-dual positive but not CD34/Eph-B4-dual positive; patches expressed Ephrin-B2, notch-4 and dll-4 but not Eph-B4 and COUP-TFII. In the venous environment patches contained neointimal cells that were CD34/Eph-B4-dual positive but not CD34/Ephrin-B2-dual positive; patches expressed Eph-B4 and COUP-TFII but not Ephrin-B2, notch-4 and dll-4. These data show that autologous tissue patches heal by acquisition of the vascular identity determined by the environment into which they are implanted, suggesting some plasticity of adult vascular identity.

Study on Urinary Metabolic Profile in Rats with Deep Venous Thrombosis Based on Pattern Recognition

To study the urinary metabolic profile in rats with deep venous thrombosis （DVT） based on metabolomics and to screen out small molecular biomarkers for the diagnosis and forensic identification of DVT. Inferior vena cava of rats was ligated to construct DVT models. The rats were randomly divided into three groups： DVT, sham, and control groups, 10 in each group. The urine of DVT and sham rats was collected during 24 hours in the metabolic cage at 48 hours after operating, meanwhile, 24 hours urine was collected in control group. The metabolic profile was analyzed by nuclear magnetic resonance. SIMCA-P 14.1 software was used for pattern recognition. The variable importance in projection （VIP） value from orthogonal PLS-DA （OPLS-DA） model combined with Mann-Whitney U test were used to search the different metabolites in the urine. The metabolic profiles of urine from DVT, sham, and control groups had significant differences. The DVT, sham, and control groups could be distinguished by the partial least squares method-discriminant analysis （PLS-DA） model. Compared with the urine of the rats in control groups, the levels of leucine, glutamine, creatine, creatinine and sucrose in the urine of DVT rats were up-regulated, and the levels of 3-hydroxybutyrate, lactate, acetone, α-oxoglutarate, citrate and hippurate were down-regulated. The different metabolites in the urine of DVT rats are expected to become its candidate biomarkers. The results can provide a research basis for the diagnosis, treatment and forensic identification of DVT.

MicroRNA-30c suppresses the pro-fibrogenic effects of cardiac fibroblasts induced by TGF-β1 and prevents atrial fibrosis by targeting TGFβRII.

Atrial fibrosis serves as an important contributor to atrial fibrillation (AF). Recent data have suggested that microRNA‐30c (miR‐30c) is involved in fibrotic remodelling and cancer development, but the specific role of miR‐30c in atrial fibrosis remains unclear. The purpose of this study was to investigate the role of miR‐30c in atrial fibrosis and its underlying mechanisms through in vivo and in vitro experiments. Our results indicate that miR‐30c is significantly down‐regulated in the rat abdominal aortic constriction (AAC) model and in the cellular model of fibrosis induced by transforming growth factor‐β1 (TGF‐β1). Overexpression of miR‐30c in cardiac fibroblasts (CFs) markedly inhibits CF proliferation, differentiation, migration and collagen production, whereas decrease in miR‐30c leads to the opposite results. Moreover, we identified TGFβRII as a target of miR‐30c. Finally, transferring adeno‐associated virus 9 (AAV9)‐miR‐30c into the inferior vena cava of rats attenuated fibrosis in the left atrium following AAC. These data indicate that miR‐30c attenuates atrial fibrosis via inhibition of CF proliferation, differentiation, migration and collagen production by targeting TGFβRII, suggesting that miR‐30c might be a novel potential therapeutic target for preventing atrial fibrosis.

Fluid in the tissue channels of vascular adventitia investigated by AFM and TEM.

Tissue channels as a part of microcirculation system have been proposed over three decades, playing an important role in fluid transportation as reported. Adventitia of inferior vena cava (IVC) is a typical hierarchical porous media with abundant tissue channels. Its fluid transportation behaviors attract massive research interest. However, the mechanism of the driving force and microstructure was lack of deep research. This study was to investigate the microstructural basis of fluid transportation within inferior vena cava (IVC). Rat IVC samples were extracted and fixed on a gelatin substrate. Four samples were randomly used as 4 cases: Case 1 with AFM loading and the fluorescent tracer adding; Case 2 with fluorescent tracer adding only; Case 3 with AFM loading only as the control group; Case 4 with no treatment. The movement of fluorescent tracer was observed by two-photon fluorescent microscope and analyzed by self-made Matlab program. The microscopic structure was characterized by high resolution TEM. The fluorescent tracer in Case 1 exhibited faster and longer transportation comparing to other cases, while in Case 2 diffused normally following Fick's law. Case 3 with only AFM loading demonstrated that collagen bundles twisting along the fluid orientation, while the bundles in Case 4 with no treatment were straggling. The brush-like macromolecule structure of collagen microfibril was found on the bundle surfaces under TEM. Transportation within loose connective tissues is observed ex vivo. AFM loading, as the mechanical stimulation resemblance to muscle constrictions and blood pulsations, can facilitate the transportation as the driving force. The brush-like glycosaminoglycan macromolecules on the surfaces of the collagen bundles can be considered as a type of hierarchical porous media, which might form the transport pathway for fluids. The possible mechanism was conducted regarding the conformation of the superficial macromolecule brushes.

Changes in hydrogen sulfide in rats with hepatic cirrhosis in different stages.

This study aimed to observe changes in the hydrogen sulfide (H2S) system in the blood and liver tissue of rats with hepatic cirrhosis at different stages by studying the effect of H2S on the course of hyperdynamic circulation in rats with hepatic cirrhosis. H2S concentration in the blood from the portal vein and inferior vena cava of hepatic cirrhosis rat model induced with carbon tetrachloride was detected on the 15th, 30th, and 52nd day. The expression of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) protein, and CBS and CSE mRNA in the liver was detected by immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR), respectively. The results indicated that H2S concentration in the blood from the portal vein and inferior vena cava of rats with hepatic cirrhosis was significantly lower than that in the control group. H2S was gradually decreased with the development of the disease and significantly lower in the blood from portal vein than in the blood of inferior vena cava at the mid-stage and the late stage groups. The expression levels of CBS and CSE protein, and CBS and CSE mRNA in the livers with hepatic cirrhosis at different stages were all higher than those in the control group, and the expression gradually increased with the development of the disease. The expression of CBS was lower than CSE in the same stages. The results indicated that the CSE mRNA was expressed predominantly in the cirrhosis groups as compared with CBS mRNA. Among experimental rats, the H2S system has an important effect on the occurrence and development of hyperdynamic circulation in rats with hepatic cirrhosis. This finding adds to the literature by demonstrating that H2S protects vascular remodelling in the liver, and that CSE is indispensable in this process.

Sulodexide Promotes Venous Contraction in Rat Inferior Vena Cava

Sulodexide (SDX) is a highly purified glycosaminoglycan composed of fast-moving heparin (80%) and dermatan sulfate (20%). SDX has both antithrombotic and profibrinolytic properties with reported benefits in chronic venous disease and other thrombotic and atherosclerotic vascular disorders. However, the effects of SDX on the vein wall structure and function are unclear. We have previously shown that matrix metalloproteinases 2 and 9 cause venous relaxation, and other studies have suggested that SDX may inhibit matrix metalloproteinase 9. The purpose of this study was to test whether SDX affects venous function and whether its venous effects are different from those in the arteries. Male rat inferior vena cava (IVC), abdominal aorta, and mesenteric artery were harvested and 3-mm circular segments were equilibrated under 0.5g, 2g, and 1g basal tension, respectively, in a tissue bath containing Krebs solution bubbled with 95% O2 5% CO2 at 37°C, and the changes in isometric contraction were recorded. Vessel segments were precontracted with the α-adrenergic receptor agonist phenylephrine (PHE, 3 × 10−7 M), and the changes in the vessel response to SDX (0.001-1 mg/mL) were measured. The % venous/arterial contraction or relaxation was calculated, and the data were presented as means ± standard error of the mean and analyzed with t-test, with P < .05 significant. In the IVC, aorta, and mesenteric artery, PHE (3 × 10−7 M) caused submaximal contraction that remained steady for at least 1 hour. In PHE-precontracted IVC, SDX caused concentration-dependent increases in contraction that reached a maximum at 1 mg/mL (SDX 62.8 ± 3.9 vs control 0.0; P < .01). In contrast, in PHE-precontracted aorta and mesenteric artery, SDX caused concentration-dependent relaxation compared with control (maximum 45.4 ± 6.0 vs 6.7 ± 6.6; 39.3 ± 6.2 vs 0.0, respectively; P < .05). SDX potentiates contraction in veins while causing relaxation in arteries. The mechanisms may involve differential effects of SDX on different matrix metalloproteinase subtypes, protease-activated receptors, and integrins in the veins vs arteries and need to be further examined. The results may have clinical implications as SDX may be helpful as a venotonic agent for chronic venous disease while promoting arterial dilation and decreasing arterial pressure.