Inferior Vena Cava Ligation Research Articles

Abstract 10282: Early Anticoagulation Improves Post-Thrombotic Syndrome Outcomes and Experimental Restoration of Blood Flow in DVT Subjects

Introduction: Despite anticoagulation (AC), up to 50% of proximal deep vein thrombosis (DVT) patients will develop the post-thrombotic syndrome (PTS). In a substudy of the ATTRACT DVT trial, catheter-directedthrombectomy/thrombolysis (CDT) in addition to AC improved PTS outcomes for patients presenting at an intermediate day (D) 4-8 symptom-onset-to-randomization (SOR) timeframe, but not at an early D0-3 or late D9+ SOR timeframe. Mechanisms underlying the role of early AC and CDT are unknown, particularly iliofemoral DVT (IFDVT) patients that preferentially benefit from CDT. Methods: First, we assessed the temporal impact of AC on Villalta and VEINES-QoL PTS scores in a post-hoc analysis of the IFDVT ATTRACT patients (N=391). Mean scores were estimated by a piecewise linear-regression growth-curve model. Next, to mechanistically explore the effects of AC on PTS measures, C57/BL6 mice (N=76) underwent inferior vena cava (IVC) ligation to produce stasis DVT. Mice then underwent true or sham de-ligation at D2 to spur restoration of blood flow (RBF). Last, enoxaparin AC was initiated at D2 and given daily until D8, at either 0, 10, or 30 mg/kg/d SQ. D4 RBF rates in the IVC, and D8 thrombus burden were assessed. Results: In IFDVT ATTRACT patients, CDT+AC improved PTS scores in the intermediate D4-8 SOR timeframe (p<0.001 vs. AC alone). However, in the early D0-3 SOR timeframe, CDT+AC did not improve PTS scores (p>0.05 vs. AC alone). In the AC alone groups, early AC D0-3 significantly improved PTS scores over delayed AC (p<0.05). In sham de-ligated mice with IVC DVT, D2 enoxaparin improved D4 RBF rates (sham, 11.1%; low-dose, 33.3%; high-dose, 40.0%). D2 enoxaparin also significantly reduced D8 thrombus weight (p<0.05, both doses vs. saline). However, in true de-ligation mice, D2 enoxaparin only mildly increased D4 RBF rates (sham, 50%; low-dose, 61.5%; high-dose, 60%), and did not decrease D8 thrombus weight (p>0.05). Conclusions: In ATTRACT patients presenting with IFDVT at an early D0-3 SOR timeframe, PTS outcomes were improved by AC but not further improved by CDT. Experimentally, early D2 AC initiation can improve RBF rates and DVT resolution. These findings suggest that achieving early RBF may reduce the risk of PTS.

Epigallocatechin-3-gallate exerts protective effect on epithelial function via PI3K/AKT signaling in thrombosis.

Venous thrombosis (VT) is one of the most frequent cardiovascular diseases, which seriously endangers people's health. Recently, the protective role of epigallocatechin-3-gallate (EGCG) against multiple cardiovascular diseases has been well studied. Nevertheless, whether EGCG is implicated in the progression of VT is still unclear. Rat models of VT were established by inferior vena cava (IVC) ligation. Histological characterization of the IVC tissues was examined by hematoxylin-eosin (H&E) staining. TUNEL assay was utilized to detect cell apoptosis in IVC tissues. The concentrations of the oxidative stress biomarkers, malondialdehyde (MDA) and superoxide dismutase (SOD), were estimated by corresponding kits. In addition, the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 in rat plasma were estimated by ELISA. Further, the expression levels of apoptosis markers (Bax, Bcl-2, and Cleaved-caspase 3) as well as key molecules p-PI3K and p-AKT in phosphoinositide 3-kinase (PI3K)/AKT signaling pathway were assessed by western blot. Compared to the sham group, the model group showed obvious thrombus formation in IVC tissues, while the EGCG treatment significantly repressed thrombosis. EGCG inhibited cell apoptosis in IVC tissues of VT rat models. The decreased SOD concentration and increased MDA concentration in the plasma of VT rats were reversed by EGCG treatment. Additionally, the elevated levels of TNF-α, IL-6 and IL-8 in the plasma of VT rats can be partially reduced by the treatment of EGCG. Finally, we also found that EGCG reduced the levels of phosphorylated (p)-PI3K and p-AKT in IVC tissues of VT rat models, indicating that the hyperactivation of the PI3K/AKT signaling pathway was inhibited by EGCG. This study proves that EGCG alleviates thrombosis, cell apoptosis, inflammatory response, and oxidative stress injury in VT by inactivating PI3K/AKT signaling pathway.

Endovascular Balloon Occlusion of the Inferior Vena Cava in Trauma: A Single-Center Case Series.

Injury to the inferior vena cava (IVC) can produce bleeding that is difficult to control. Endovascular balloon occlusion provides rapid vascular control without extensive dissection and may be useful in large venous injuries, especially in the juxtarenal IVC. We describe the procedural steps, technical considerations, and clinical scenarios for using the Bridge occlusion balloon (Philips) in IVC trauma. We present a single-center case series of 5 patients in which endovascular balloon occlusion of the IVC was used for hemorrhage control. All 5 patients were men (median age 35, range 22 to 42 years). They all sustained penetrating injuries-4 gunshot wounds and 1 stab wound. Median presenting Shock Index was 0.7 (range 0.5 to 1.5). Median initial lactate was 5.4 mmol/L (range 4.6 to 6.9 mmol/L). There were 2 suprarenal IVC injuries, 2 juxtarenal injuries, and 3 infrarenal injuries. Four patients underwent primary repair of their injury, and one underwent IVC ligation. Four patients had intraoperative Resuscitative Endovascular Balloon Occlusion of the Aorta for inflow control and afterload support. The median number of total blood products transfused during the initial operation was 37 units (range 16 to 77 units). Four patients underwent damage control operations, and one patient had a single definitive operation. Four of the 5 patients (80%) survived to discharge with the lone mortality being due to other injuries. Endovascular balloon occlusion serves as a valuable adjunct in the management of IVC injury and demonstrates the potential of hybrid open-endovascular operative techniques in abdominal vascular trauma.

Epigenetic repression of THBD transcription by BRG1 contributes to deep vein thrombosis

BackgroundDeep vein thrombosis (DVT) with its major complication, pulmonary embolism, is a global health problem. Endothelial dysfunction is involved in the pathogenesis of DVT. We have previously demonstrated that endothelial specific deletion of Brahma-related gene 1 (BRG1) ameliorates atherosclerosis and aneurysm in animal models. Whether endothelial BRG1 contributes to DVT development remains undetermined. MethodsDVT was induced in mice by ligation of inferior vena cava. Deletion of BRG1 in endothelial cells was achieved by crossing the Cdh5-ERT-Cre mice with the Brg1loxp/loxp mice. ResultsHere we report that compared to the wild type mice, BRG1 conditional knockout (CKO) mice displayed substantially decreased DVT susceptibility characterized by decreased weight and size of thrombus and reduced immune infiltration. In endothelial cells, thrombomodulin (THBD) expression was significantly decreased by TNF-α stimulation, while BRG1 knockdown or inhibition recovered THBD expression. Further analysis revealed that BRG1 deficiency decreased the CpG methylation levels of the THBD promoter induced by TNF-α. Mechanistically, BRG1 directly upregulated DNMT1 expression after TNF-α treatment in endothelial cells. More importantly, administration of a small-molecule BRG1 inhibitor PFI-3 displayed potent preventive and therapeutic potentials in the DVT model. ConclusionsOur findings implicate BRG1 as an important regulator of DVT pathogenesis likely through epigenetic regulation of THBD expression in endothelial cells and provide translational proof-of-concept for targeting BRG1 in DVT intervention.

MicroRNA-342-3p loaded by human umbilical cord mesenchymal stem cells-derived exosomes attenuates deep vein thrombosis by downregulating EDNRA.

Exosomes (exos) exert biological functions to maintain the dynamic balance of cells and tissues by transferring biological cargo to recipient cells. Thus, this study explored human umbilical cord mesenchymal stem cells (hucMSCs)-derived exo transfer of microRNA (miR)-342-3p in deep vein thrombosis (DVT). DVT rat models were established via inferior vena cava (IVC) ligation. HucMSCs-exos were extracted and injected into rats with DVT to observe whether they could influences thrombus formation in vivo. HucMSCs-exos were co-cultured with human umbilical vein endothelial cells (HUVECs) in vitro to observe angiogenesis. miR-342-3p and endothelin A receptor (EDNRA) expression in rats with DVT, as well as their interaction was analyzed. miR-342-3p was downregulated and EDNRA was upregulated in rats with DVT. HucMSCs-exos inhibited the formation of thrombus in rats with DVT, as well as promoted angiogenesis of HUVECs. Upregulated miR-342-3p delivery by hucMSCs-exos alleviated DVT in rats and improved angiogenesis of HUVECs. miR-342-3p targeted EDNRA, and the effect of hucMSCs-exos transfer of upregulated miR-342-3p was rescued by overexpressing EDNRA. Briefly, miR-342-3p loaded by hucMSCs-exos attenuates DVT by downregulating EDNRA, offering a novel direction to treat DVT.

Inhibition of platelet-derived growth factor pathway suppresses tubulointerstitial injury in renal congestion.

Objective:Increased central venous pressure in congestive heart failure is responsible for renal dysfunction, which is mediated by renal venous congestion. Pericyte detachment from capillaries after renal congestion might trigger renal fibrogenesis via pericyte-myofibroblast transition (PMT). Platelet-derived growth factor receptors (PDGFRs), which are PMT indicators, were upregulated in our recently established renal congestion model. This study was designed to determine whether inhibition of the PDGFR pathway could suppress tubulointerstitial injury after renal congestion.Methods:The inferior vena cava between the renal veins was ligated in male Sprague-Dawley rats, inducing congestion only in the left kidney. Imatinib mesylate or vehicle were injected intraperitoneally daily from 1 day before the operation. Three days after the surgery, the effect of imatinib was assessed by physiological, morphological and molecular methods. The inhibition of PDGFRs against transforming growth factor-β1 (TGFB1)-induced fibrosis was also tested in human pericyte cell culture.Results:Increased kidney weight and renal fibrosis were observed in the congested kidneys. Upstream inferior vena cava (IVC) pressure immediately increased to around 20 mmHg after IVC ligation in both the imatinib and saline groups. Although vasa recta dilatation and pericyte detachment under renal congestion were maintained, imatinib ameliorated the increased kidney weight and suppressed renal fibrosis around the vasa recta. TGFB1-induced elevation of fibrosis markers in human pericytes was suppressed by PDGFR inhibitors at the transcriptional level.Conclusion:The activation of the PDGFR pathway after renal congestion was responsible for renal congestion-induced fibrosis. This mechanism could be a candidate therapeutic target for renoprotection against renal congestion-induced tubulointerstitial injury.

Resection of retroperitoneal tumors with inferior vena cava involvement without caval reconstruction.

Retroperitoneal tumors with involvement of the inferior vena cava (IVC) often require resection of the IVC to achieve complete tumor removal. This study evaluates the safety and efficacy of IVC ligation without caval reconstruction. A retrospective chart review of patients who underwent IVC ligation(IVC-Ligation) and IVC resection with reconstruction (IVC-Reconstruction) at our institution between May 2004 and April 2021 was performed. Outcomes from the two surgical techniques were compared via univariate analysis using the Kruskal-Wallis test for continuous variables and Fisher's exact test for categorical variables. Forty-nineIVC-Ligation and sixIVC-Reconstruction surgeries were identified. There were no differences in baseline demographics, tumor characteristics, complication rates, postoperative morbidity, or overall 5-year survival between groups. IVC-Reconstruction patients were more likely to require intensive care unit admission (83% vs. 33%; p = 0.0257) and the IVC-Ligation cohort had a tendency to present with nondebilitating postoperative lymphedema (35% vs. 0%; p = 0.1615), which resolved for most patients. IVC-Ligation is a viable surgical option for select patients presenting with retroperitoneal tumors with IVC involvement and provides acceptable short- and medium-term outcomes.

A Factor XIa Inhibitor Engineered from Banded Krait Venom Toxin: Efficacy and Safety in Rodent Models of Arterial and Venous Thrombosis.

Activated factor XI (FXIa) is an important antithrombotic drug target. Clinical and pre-clinical data have demonstrated that its inhibition attenuates thrombosis with minimal risk of excessive bleeding. We isolated Fasxiator from the venom of banded krait Bungarus fasciatus and subsequently engineered FasxiatorN17R,L19E, with improved affinity (Ki = 0.9 nM) and selectivity towards FXIa. Here, we assess the in vivo efficacy and bleeding risk of rFasxiatorN17R, L19E in pre-clinical animal models. Rats injected intravenously (i.v.) with bolus rFasxiatorN17R, L19E showed the specific in vivo attenuation of the intrinsic coagulation pathway, lasting for at least 60 min. We performed the in vivo dose-ranging experiments for rFasxiatorN17R, L19E as follows: FeCl3-induced carotid artery occlusion in rats (arterial thrombosis); inferior vena cava ligation in mice (venous thrombosis); tail bleeding time in both rats and mice (bleeding risk). Head-to-head comparisons were made using therapeutic dosages of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) for arterial and venous thrombosis, respectively. In the arterial thrombosis model, 2 mg/kg i.v. rFasxiatorN17R,L19E achieved a similar antithrombotic efficacy to that of UFH, with >3-fold lower bleeding time. In the venous thrombosis model, the 10 mg/kg subcutaneous (s.c.) injection of rFasxiatorN17R,L19E achieved similar efficacy and bleeding levels to those of LMWH enoxaparin. Overall, rFasxiatorN17R,L19E represents a promising molecule for the development of FXIa-targeting anticoagulants.

Effects of wasp venom on venous thrombosis in rats.

Objective(s):This study aimed to investigate the potential effects of wasp venom (WV) from Vespa magnifica on antithrombosis in rats with inferior vena cava (IVC) thrombosis.Materials and Methods:The thrombosis rat model was established by improving the IVC stenosis, in which rats were subjected to IVC ligation for 75 min. Rats were administered argatroban (IP) or WV (s.c.) for 4 hr after IVC thrombosis. The weight, inhibition rate, and pathological morphology of the thrombosis induced by IVC ligation and the variation in four coagulation parameters, coagulation factors, and CD61+CD62P+ were simultaneously determined in IVC rats.Results:The thrombus formed as a result of IVC ligation was stable. Compared with the control group, the weight of the thrombus was significantly reduced in the argatroban group. Thrombus weight was reduced by treatment with 0.6, 0.2, and 0.05 mg/kg WV, with inhibition rates of 52.19%, 35.32%, and 28.98%, respectively. Inflammatory cells adhered to and infiltrated the vessel wall in the IVC group more than in the sham group. However, the pathological morphology and CD61+CD62P+ of the WV treatment groups tended to be normal. Conclusion:We improved the model of IVC thrombosis to be suitable for evaluation of antithrombotic drugs. Our findings demonstrated that WV could inhibit IVC thrombosis associated with reducing coagulation factors V and CD61+CD62p expression in rats.

Inferior vena cava ligation in patient victim of gunshot wound

Inferior vena cava ligation in patient victim of gunshot wound

What happens after they survive? The role of anticoagulants and antiplatelets in IVC injuries

BackgroundVenous thromboembolism (VTE) after an inferior vena cava (IVC) injury is a devastating complication. Current practice involves variable use of anticoagulation and antiplatelet (AC/AP) agents. We hypothesized that AC/AP can...

An in situ inferior vena cava ligation-stenosis model to study thrombin generation rates with flow

BackgroundBlood flow-induced shear stress affects platelet participation in coagulation and thrombin generation. We aimed to develop an in vivo model to characterize thrombin generation rates under flow.MethodsAn in situ inferior vena cava (IVC) ligation-stenosis model was established using C57BL/6 mice. Wild type C57BL/6 mice were fed normal chow diet for two weeks before experiments. On the day of experiments, mice were anesthetized, followed by an incision through the abdominal skin to expose the IVC, which was then ligated (followed by reperfusion through a stenosis for up to 2 h). IVC blood flow rate was monitored using a Transonic ultrasound flow meter. In sham animals, the IVC was exposed following the same procedure, but no ligation was applied. Thrombin generation following IVC ligation was estimated by measuring mouse plasma prothrombin fragment 1–2 concentration. Mouse plasma factor Va concentration was measured using phospholipids and a modified prothrombinase assay. Blood vessel histomorphology, vascular wall ICAM-1, von Willebrand Factor, tissue factor, and PECAM-1 expression were measured using immunofluorescence microscopy.ResultsIVC blood flow rate increased immediately following ligation and stenosis formation. Sizable clots formed in mouse IVC following ligation and stenosis formation. Both plasma factor Va and prothrombin fragment 1–2 concentration reduced significantly following IVC ligation/stenosis, while no changes were observed with ICAM-1, von Willebrand Factor, tissue factor and PECAM-1 expression.ConclusionClot formation was successful. However, the prothrombin-thrombin conversion rate constant in vivo cannot be determined as local thrombin and FVa concentration (at the injury site) cannot be accurately measured. Modification to the animal model is needed to further the investigation.

Robot-Assisted Laparoscopic IVC Treatment Strategy in Retroperitoneal Tumors.

ObjectivesTo show the practice of robot-assisted laparoscopic inferior vena cava (IVC) treatment strategies in patients with retroperitoneal tumors.Patients and MethodsFrom October 2020 to July 2021, 17 patients with retroperitoneal tumors successfully underwent robot-assisted laparoscopic tumor resection with IVC management. The patient details, tumor characteristics, intraoperative data, pathological features and severe complications were assessed. The IVC treatment strategies were divided into 4 ways: ①local resection and primary repair of the IVC; ②IVC ligation; ③ IVC reconstruction by bovine pericardial grafts; and ④ IVC transection and anastomosis.ResultsIn terms of IVC management, 5 cases had conventional total occlusion of the IVC and its branches, 3 cases had delayed occlusion of the proximal IVC technique, 2 cases had IVC resection by Satinsky clamp, 5 cases had IVC ligation, 1 case had IVC reconstruction by bovine pericardial grafts and 1 case had IVC transection and anastomosis. The median operation time was 151 min, and blood loss was 500 ml. There was no severe complication perioperatively. The follow-up time of 17 patients was 8 to 17 months (median: 12 months). No local recurrence or overall death was found during follow-up.ConclusionsThese robot-assisted laparoscopic IVC treatment strategies were considered to be safe and feasible in experienced centers, as well as helpful to completely remove the tumor for better oncological prognosis and restore the blood reflux of IVC as much as possible to ensure fewer postoperative complications.

Abstract 157: Role Of Systemic Platelet Levels In Venous Thrombosis And Resolution In A Murine Model Of Inferior Vena Cava Constriction

Background: Platelet role in primary clot formation in response to vessel wall injury is well established; however, the role of systemic platelet levels in deep vein thrombosis (DVT) and its sequelae is unclear. Their interaction with the venous endothelium under low shear stress, regulation of thrombosis, and mediation of both innate and adaptive immune responses through selectin and toll-like receptor expression, respectively, warrants further investigation into their role in DVT formation and resolution. In this study, we present a role for systemic platelet levels in regulating thrombus resolution. Methods: Wildtype, male or female CD1 mice were treated with a thrombopoietin antisense oligonucleotide (TPO-ASO) at 10 mg/kg, eltrombopag at 75 mg/ kg, saline (control), or a scrambled TPO-ASO (control) at 8 mg/ kg prior to surgical creation of a venous thrombus by ligation of the infra-renal inferior vena cava (IVC). Peak scaled thrombus weights (i.e., linear density measured using a ratio of the clot and IVC weight scaled to the length of the IVC) were measured to characterize the early resolution of the thrombus through involution and recanalization. Mice were euthanized on postoperative days 3 and 7 to measure the formation and resolution of the thrombus, respectively. Results: Platelet levels were elevated and decreased by over 30% by the day of surgical treatment after TPO-ASO and eltrombopag treatments, respectively. Scaled thrombus weights were significantly different (p = 0.045, Kruskal Wallis) between groups on day 7 after IVC constriction. Post-hoc analysis (Dunn Test with Benjamini-Hochberg correction) revealed that the TPO-ASO group (mean = 25.4 +/- 0.9 mg/cm) had significantly decreased (p = 0.018) scaled thrombus weights compared to the mice treated with eltrombopag (mean = 35.3 +/- 6.5 mg/cm) on day 7. Thrombus formation on day 3 was not statistically different between treatment groups. Conclusion: Achieving a minimum threshold of 30% reduction of systemic platelet levels by TPO-ASO enhanced thrombus resolution, but not thrombus formation, in our stasis model of rodent DVT resolution. These data suggest a potential role for systemic platelet levels in regulating thrombus resolution.

Proline-rich tyrosine kinase Pyk2 regulates deep vein thrombosis.

Deep vein thrombosis results from the cooperative action of leukocytes, platelets, and endothelial cells. The proline-rich tyrosine kinase Pyk2 regulates platelet activation and supports arterial thrombosis. In this study, we combined pharmacological and genetic approaches to unravel the role of Pyk2 in venous thrombosis. We found that mice lacking Pyk2 almost completely failed to develop deep venous thrombi upon partial ligation of the inferior vena cava. Pyk2-deficient platelets displayed impaired exposure of phosphatidylserine and tissue factor expression by endothelial cells and monocytes was completely prevented by inhibition of Pyk2. In human umbilical vein endothelial cells (HUVEC), inhibition of Pyk2 hampered IL-1β-induced expression of VCAM and P-selectin, and von Willebrand factor release. Pyk2-deficient platelets showed defective adhesion on von Willebrand factor and reduced ability to bind activated HUVEC under flow. Moreover, inhibition of Pyk2 in HUVEC strongly reduced platelet adhesion. Similarly, Pyk2-deficient neutrophils were unable to efficiently roll and adhere to immobilized endothelial cells under venous flow conditions. Moreover, platelets and neutrophils from Pyk2-knockout mice showed defective ability to form heterogeneous aggregates upon stimulation, while platelet monocyte interaction occurred normally. Consequently, platelet neutrophil aggregates, abundant in blood of wild-type mice upon inferior vena cava ligation, were virtually undetectable in Pyk2-knockout mice. Finally, we found that expression of Pyk2 was required for NETosis induced by activated platelets. Altogether our results demonstrate a critical role of Pyk2 in the regulation of the coordinated thromboinflammatory responses of endothelial cells, leukocytes and platelets leading to venous thrombosis. Pyk2 may represent a novel promising target in the treatment of deep vein thrombosis.

Exosomal myeloperoxidase as a biomarker of deep venous thrombosis.

BackgroundDeep vein thrombosis (DVT) often occurs following major orthopedic surgery. In this study, we investigated specific exosomal proteins as potential diagnostic biomarkers of DVT.MethodsProteomic analysis of exosomes from four DVT patients and healthy controls (n=4) was performed by mass spectrometry. The model animals were evaluated at 1 inferior vena cava ligation [(IVCL)-1D], 3 (IVCL-3D), and 7 (IVCL-7D) days after IVCL. Endothelial cells in the thrombus segment were examined using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays and hematoxylin and eosin (HE) staining. Myeloperoxidase (MPO) expression in the damaged vessel was detected by immunofluorescence staining. Exosomes were co-cultured with human umbilical vein endothelial cells (HUVECs) and cell proliferation was estimated using Cell Counting Kit-8 (CCK-8) assays.ResultsA total of 78 differentially expressed proteins (DEPs; 38 downregulated and 40 upregulated) were identified in the DVT group. In the rat DVT model, endothelial cells were damaged continuously after thrombosis, with the most serious injury in the IVCL-3D group, after which signs of endothelial repair were apparent. The IVCL-1D group showed the highest levels of vascular endothelial cell apoptosis and MPO increased sharply in the IVCL-1D and IVCL-3D groups, but had almost disappeared in the IVCL-7D group. In co-culture, plasma exosomes isolated from DVT model rats were efficiently absorbed by HUVECs, with markedly lower HUVECs growth and higher levels of apoptosis in the IVCL-1D and IVCL-3D groups compared with the control group.ConclusionsOur findings suggest that exosomes may be involved in endothelial cell injury during DVT. The exosomal protein MPO is a potential biomarker of early stage DVT.

Investigating the role of receptor interacting protein kinase 3 in venous thrombosis

ObjectiveVenous thromboembolism is a disease that encompasses both deep vein thrombosis and pulmonary embolism. Recent investigations have shown that receptor interacting protein kinase 3 (RIPK3), a protein known for its role in the programmed form of cell death necroptosis, may play a role in thrombosis. Specifically, RIPK3 has been shown to promote platelet activation in arterial thrombosis and mixed lineage kinase domain-like pseudokinase (MLKL), a protein downstream of RIPK3 in the necroptosis pathway, has been shown to promote neutrophil extracellular trap formation in deep vein thrombosis. This investigation sought to comprehensively investigate the role of RIPK3 in deep vein thrombogenesis. MethodsThe inferior vena cava ligation and stenosis models of deep vein thrombosis were used in C57BL/6J, RIPK3 wild-type (Ripk3+/+) and RIPK3-deficient (Ripk3–/–) mice. Downstream tissue analyses included measurement of thrombus weight and histological and Western blot analysis of tissues for markers of necroptosis and cell death. A subset of C57BL/6J mice were treated with a RIPK3 inhibitor to determine the effect on venous thrombosis. ResultsC57BL/6J mice showed significant increases in thrombus weight from 6 to 48 hours. During the same time frame, RIPK3 progressively accumulated in the vein wall (a 35-fold increase from 0 to 48 hours). RIPK3 was present in the thrombus; however, it decreased with time. Although present in the thrombus, MLKL was nearly undetectable in the vein wall by Western blot at any timepoint. Immunostaining confirmed the high accumulation of RIPK3 in the vein wall, primarily colocalized to endothelial and smooth muscle cells. Phosphorylated MLKL, the active form of MLKL and executioner of necroptotic cell death, was detectable by immunostaining in the thrombus, but was present at low to undetectable levels in the vein wall. Propidium iodide and terminal deoxynucleotidyl transferase dUTP nick end labeling staining revealed a high burden of necrotic and apoptotic cells within the thrombus at 48 hours, but a relatively lower burden within the vein wall. Despite robust accumulation of RIPK3 within the vessel wall and the thrombus, knockout and inhibition of RIPK3 failed to impact thrombus incident or weight at 48 hours after inferior vena cava ligation. Neutrophil extracellular trap burden did not differ between Ripk3+/+ and Ripk3–/– mice. ConclusionsIn mice, the vein wall responded to deep vein thrombosis induction with elevation of RIPK3 without showing markers of necroptosis and apoptosis. Studies using genetic or pharmacological inhibition of RIPK3 suggest that this cell death mediator may not have a major role in the acute phase of venous thrombogenesis. Further investigation is needed to determine if RIPK3 plays a potentially non-necroptotic role within the vein wall during later stages of thrombus resolution and vein wall remodeling.

Reconstruction of caval veins

To study the possibilities and results of reconstruction of caval veins. We analyzed the results of reconstruction of caval veins in 31 patients (19 men and 12 women) including superior vena cava (SVC) in 5 cases and inferior vena cava (IVC) in 26 cases. Penetrating wounds with vascular damage were found in 8 patients. Iatrogenic damage to IVC was observed in 19 patients (nephrectomy for kidney cancer - 2, nephrectomy for secondary kidney wrinkling - 1, echinococcectomy from retroperitoneal space - 1, adrenalectomy for adrenal tumors - 5, right-sided lumbar sympathectomy - 1, resection of abdominal aortic aneurysm - 1, resection of a large retroperitoneal tumor - 6). Iatrogenic damage to SVC occurred in 2 patients during resection of mediastinal tumor. In other 4 cases, elective surgery for mediastinal tumor (1), pancreatic head cancer (2) and liver alveococcosis (1) was accompanied by resection and replacement of caval veins. All interventions for caval vein injury were performed under adequate infusion therapy. Seven (22.6%) patients died. One patient with blunt chest trauma and damage to SVC died during thoracotomy. In another patient, infrarenal IVC was intersected during mobilization of retroperitoneal hydatid cyst that required ligation for vital indications. High venous hypertension below the ligature led to eruption of sutures on the venous stump. The patient died from hypovolemia after additional IVC ligation. Other 5 patients died in early postoperative period without leaving the state of shock. These patients had damage to retrohepatic segment of IVC (1), vascular-organ (1) and iatrogenic (3) injuries. One patient died from pulmonary embolism, two patients - from venous bleeding between the 2nd and the 5th postoperative days. Patients died before reoperations. Two patients with postoperative bleeding underwent redo surgery with favorable outcomes. One patient underwent redo surgery for peritonitis with a favorable result. Thus, 7 (22.6%) patients with caval vein injury died in intraoperative and early postoperative period. Non-specific complications occurred in 4 (12.9%) patients. These events were corrected by conservative measures. Other 24 (77.4%) patients with traumatic and iatrogenic injuries of caval veins were discharged. Caval vein injury is less common event compared to other vascular damages. Nevertheless, this complication is accompanied by severe blood loss, shock and hypovolemia. We can only assume damage to a great vessel in patients with penetrating wounds before surgery and appropriate symptoms of internal bleeding. However, final diagnosis is made during surgery. Hemostasis is a responsible and difficult surgical stage in these patients. There is usually no alternative to reconstructive surgery in these cases. However, ligation is permissible in extremely ill patients and only in infrarenal segment of IVC. Vascular suture is a more acceptable and effective option for reconstruction. However, patch repair is advisable for large defects. In our opinion, this approach is better regarding long-term patency compared to total replacement with synthetic prostheses.

Sphingosine-1-phosphate promotes tumor development and liver fibrosis in mouse model of congestive hepatopathy.

Chronic liver congestion reflecting right-sided heart failure (RHF), Budd-Chiari syndrome, or Fontan-associated liver disease (FALD) is involved in liver fibrosis and HCC. However, molecular mechanisms of fibrosis and HCC in chronic liver congestion remain poorly understood. Here, we first demonstrated that chronic liver congestion promoted HCC and metastatic liver tumor growth using murine model of chronic liver congestion by partial inferior vena cava ligation (pIVCL). As the initial step triggering HCC promotion and fibrosis, gut-derived lipopolysaccharide (LPS) appeared to induce LSECs capillarization in mice and in vitro. LSEC capillarization was also confirmed in patients with FALD. Mitogenic factor, sphingosine-1-phosphate (S1P), was increased in congestive liver and expression of sphingosine kinase 1, a major synthetase of S1P, was increased in capillarized LSECs after pIVCL. Inhibition of S1P receptor (S1PR) 1 (Ex26) and S1PR2 (JTE013) mitigated HCC development and liver fibrosis, respectively. Antimicrobial treatment lowered portal blood LPS concentration, LSEC capillarization, and liver S1P concentration accompanied by reduction of HCC development and fibrosis in the congestive liver. In conclusion, chronic liver congestion promotes HCC development and liver fibrosis by S1P production from LPS-induced capillarized LSECs. Careful treatment of both RHF and liver cancer might be necessary for patients with RHF with primary or metastatic liver cancer.

Inflammatory Monocyte Counts Determine Venous Blood Clot Formation and Resolution.

Monocytes are thought to be involved in venous thrombosis but the role of individual monocyte subpopulations on thrombus formation, clot inflammation, and degradation is an important unresolved issue. We investigate the role of inflammatory Ly6Chi monocytes in deep vein thrombosis and their potential therapeutic impact. Frequencies and compositions of blood monocytes were analyzed by flow cytometry in CCR2-/- (C-C chemokine receptor type 2) and wild-type mice of different ages and after treatment with the NR4A1 (nuclear receptor group 4 family A member 1, Nur77) agonist CnsB (cytosporone B). TF (tissue factor) sufficient and deficient Ly6Chi monocytes were adoptively transferred into aged CCR2-/- mice. Thrombus formation and size were followed by ultrasound over a 3-week period after surgical reduction of blood flow (stenosis) in the inferior vena cava. Reduced numbers of peripheral monocytes in aged (>30 w) CCR2-/- mice are accompanied by reduced thrombus formation after inferior vena cava ligation. Reducing the number of inflammatory Ly6Chi monocytes in wild-type mice by CsnB treatment before ligation, similarly suspends clotting, while later treatment (d1 or d4) reduces thrombus growth and accelerates resolution. We describe how changes in inflammatory monocyte numbers affect the gradual differentiation of monocytes in thrombi and show that only tissue factor-competent Ly6Chi monocytes restore thrombosis in aged CCR2-/- mice. We conclude that the number of inflammatory Ly6Chi monocytes controls deep vein thrombosis formation, growth, and resolution and can be therapeutically manipulated with a NR4A1 agonist at all disease stages.