Magnetic Resonance Imaging Features under Deep Learning Algorithms in Evaluated Cerebral Protection of Craniotomy Evacuation of Hematoma under Propofol Anesthesia.

This study aimed to explore the value of magnetic resonance imaging (MRI) features based on deep learning super-resolution algorithms in evaluating the value of propofol anesthesia for brain protection of patients undergoing craniotomy evacuation of the hematoma. An optimized super-resolution algorithm was obtained through the multiscale network reconstruction model based on the traditional algorithm. A total of 100 patients undergoing craniotomy evacuation of hematoma were recruited and rolled into sevoflurane control group and propofol experimental group. Both were evaluated using diffusion tensor imaging (DTI) images based on deep learning super-resolution algorithms. The results showed that the fractional anisotropic image (FA) value of the hind limb corticospinal tract of the affected side of the internal capsule of the experimental group after the operation was 0.67 ± 0.28. The National Institute of Health Stroke Scale (NIHSS) score was 6.14 ± 3.29. The oxygen saturation in jugular venous (SjvO2) at T4 and T5 was 61.93 ± 6.58% and 59.38 ± 6.2%, respectively, and cerebral oxygen uptake rate (CO2ER) was 31.12 ± 6.07% and 35.83 ± 7.91%, respectively. The difference in jugular venous oxygen (Da-jvO2) at T3, T4, and T5 was 63.28 ± 10.15 mL/dL, 64.89 ± 13.11 mL/dL, and 66.03 ± 11.78 mL/dL, respectively. The neuron-specific enolase (NSE) and central-nerve-specific protein (S100ß) levels at T5 were 53.85 ± 12.31 ng/mL and 7.49 ± 3.16 ng/mL, respectively. In terms of the number of postoperative complications, the patients in the experimental group were better than the control group under sevoflurane anesthesia, and the differences were substantial (P < 0.05). In conclusion, MRI images based on deep learning super-resolution algorithm have great clinical value in evaluating the degree of brain injury in patients anesthetized with propofol and the protective effect of propofol on brain nerves.

Anticoagulation Strategies in the Management of Lemierre Syndrome: A Systematic Review of the Literature.

OBJECTIVE: To determine the optimal anticoagulation strategy in patients diagnosed with Lemierre Syndrome (LS). DATA SOURCES: A systematic review in accordance with PRISMA guidelines was conducted using PubMed, MEDLINE, Scopus, ProQuest, and CINAHL from January to April 2020. Search terms included "Lemierre Syndrome" AND "anticoagulation" NOT "prophylaxis" OR "atrial fibrillation," in addition to a list of parenteral and oral anticoagulants. Adult patients who developed a clot and required systemic anticoagulation as a result of LS were included in this review. STUDY SELECTION AND DATA EXTRACTION: A total of 4180 records were initially identified, though following the removal of duplicates and nonrelevant entries, 216 full-text articles were reviewed for inclusion; 13 articles were ultimately included. DATA SYNTHESIS: The majority (11/14) of patients developed thromboses of the internal jugular veins, which corresponds to the pathophysiology of LS. Anticoagulation strategies were varied in the included literature, though 12/14 patients initially received a parenteral product. Two patients received a direct-acting oral anticoagulant (DOAC) following either intravenous heparin or subcutaneous enoxaparin and had outcomes similar to patients transitioned to warfarin. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Anticoagulation in LS is a clinical controversy because the thromboembolic events have rarely led to significant complications; thrombi typically resolve independently, and concerns for bleeding risks are well founded; however, this review indicates both the efficacy and safety of anticoagulation. CONCLUSIONS: Anticoagulation is both efficacious and safe in LS, including treatment using a DOAC. Although further studies are needed, clinicians should consider a duration of anticoagulation of 6 to 12 weeks.

Vasoreactivity of the Murine External Jugular Vein and Carotid Artery.

INTRODUCTION: Impaired venous reactivity has potential to contribute to clinically significant pathologies such as arteriovenous fistula (AVF) maturation failure. Vascular segments commonly used in murine preclinical models of AVF include the carotid artery and external jugular vein. Detailed descriptions of isometric procedures to evaluate function of murine external jugular vein ex vivo have not been previously published. OBJECTIVE: To establish isometric procedures to measure naive murine external jugular vein reactivity ex vivo. METHODS: Vasomotor responses of external jugular veins and ipsilateral common carotid arteries from C57BL/6 mice were evaluated using isometric tension procedures. RESULTS: External jugular veins developed tension (p < 0.05) to potassium chloride and U-46619, but not to phenylephrine, whereas common carotid arteries responded to all 3 agents (p < 0.05). While maximal responses to acetylcholine (ACh) were similar between the venous and arterial segments, the dose required to achieve this value was lower (p < 0.05) in the artery versus vein. Nitric oxide synthase inhibition attenuated (p < 0.05) but did not abolish ACh-evoked vasorelaxation in both vascular segments, whereas cyclooxygenase blockade had no effect. Endothelium-independent vasorelaxation to sodium nitroprusside was similar in the artery and vein. CONCLUSION: Vasorelaxation and vasocontraction can be reliably assessed in the external jugular vein in C57BL/6 mice using isometric procedures.

Adventitial Collagen Crosslink Reduces Intimal Hyperplasia in a Rabbit Arteriovenous Graft Model.

BACKGROUND: Intimal hyperplasia (IH) is the initial lesion of vein graft failure after coronary artery bypass grafting. The weak venous wall is likely one of the primary reasons for IH after exposure to the arterial environment. We investigate whether adventitial collagen cross-link by glutaraldehyde (GA) reinforces the venous wall and then reduces IH. MATERIALS AND METHODS: Adventitial collagen cross-link by 0.3% GA was performed on the rabbit jugular veins. The degree of cross-link was accessed by tensile test. The jugular vein with or without cross-link was implanted into the carotid artery of rabbit. Vein dilatation at the immediate anastomosis and pathological remodeling of vein graft after 4 wk was assessed. RESULTS: Tensile test indicated that the mechanical property of 3-min cross-linked veins more closely resembled that of the carotid artery. In rabbit arteriovenous graft models, 3-min adventitial collagen cross-link limited overdistension (diameter: 3.24 mm versus 4.65 mm, P < 0.01) at the immediate anastomosis and reduced IH (intima thickness: 78.83 µm versus 140.19 µm, P < 0.01) of vein grafts 4 wk after implantation in the cross-link group as compared with the graft group (without cross-link). Compared with the cross-link group, the expression of proliferating cell nuclear antigen and vascular cell adhesion molecule-1 increased significantly at both the mRNA and protein levels within the graft group (P < 0.01), but the expression of smooth muscle-22α decreased significantly (P < 0.01). CONCLUSIONS: Adventitial collagen cross-link by GA increased the vessel stiffness and remarkably reduced IH in a rabbit arteriovenous graft model.

Vascular endothelium damage from catheter-induced mechanical stimulation causes catheter sleeve formation in a rabbit model.

BACKGROUND: Intravenous catheters are widely used but are often removed due to complications associated with catheter sleeve formation. A catheter sleeve can develop from a thrombus, and catheter-induced vascular endothelium damage may be a critical factor for thrombus formation. We investigated the effect of catheter-induced mechanical stimulation on venous endothelial cells and catheter sleeve formation and the efficacy of anti-thrombogenic technology for preventing catheter sleeve formation in vivo. METHODS: We surgically implanted poly(2-methoxyethyl acrylate)-coated and uncoated catheters with and without a stylet into the right external jugular vein of a rabbit model for 14 days. Catheter sleeve formation and the ratio of residual venous endothelial cells were compared using histological examination and immunostaining with an anti-CD31 antibody, respectively. RESULTS: Stiffening an uncoated catheter with a stylet induced catheter sleeve formation along more than two-thirds of the length of the catheter. The ratios of residual venous endothelial cells at the tip of uncoated catheters with and without a stylet were 3% and 36%, respectively. While poly(2-methoxyethyl acrylate) coating also reduced the ratio of venous endothelial cells at the tip of the stiffened catheter (12%), it prevented external thrombus and catheter sleeve formation. CONCLUSION: High levels of mechanical stimulation can affect catheter-related thrombosis and promote catheter sleeve formation, and anti-thrombogenic technology such as a poly(2-methoxyethyl acrylate) coating reduces thrombus formation and can prevent catheter sleeve formation on stiffened catheters. Further studies are required to determine the maximum degree of venous endothelial cell damage before catheter sleeve formation and to compare other anti-thrombogenic technologies with poly(2-methoxyethyl acrylate) for preventing catheter sleeve formation.

Application of medical adhesive inhibits intimal hyperplasia involving the downregulation of ERK1/2 and eNOS levels.

Vein graft remains the most broadly applied vascular material in coronary artery bypass surgery. However, the restenosis rate of the vein bridge following angioplasty is high. The present study investigated the effect of medical adhesive on vascular intimal hyperplasia, in addition to the signal transduction mechanism. A total of 36 New Zealand white rabbits were divided into three groups at random, including the normal group, the surgery group and the medical adhesive spray group. Following surgery for transplantation of the left external jugular vein to the ipsilateral common carotid artery for 4 weeks, the thickness and area of the intima and media of the vessel were measured on formalin­fixed, paraffin wax­embedded pathological sections using hematoxylin­eosin staining, and alterations in the expression of proliferating cell nuclear antigen (PCNA), platelet endothelial cell adhesion molecule 1 (PECAM­1), vascular cell adhesion protein 1 (VCAM­1), extracellular signal­regulated kinase (ERK)1/2, and endothelial nitric oxide synthase (eNOS) were detected by immunohistochemical staining, reverse transcription­quantitative polymerase chain reaction analysis and western blotting. The levels of intimal hyperplasia in the medical adhesive spray group were markedly decreased compared with the surgery group. Consistently, PCNA, PECAM­1 and VCAM­1 were underexpressed in the medical adhesive spray group compared with the surgery group. ERK1/2 and eNOS were underexpressed in the medical adhesive spray group compared with the surgery group. Therefore, the application of medical adhesive may inhibit intimal hyperplasia, which may be associated with the restriction of the over­distension of the vein graft by downregulating the ERK1/2 and eNOS levels, reducing injury to the vascular intima and inhibiting the signaling pathway involved in intimal hyperplasia.

Perivascular delivery of resolvin D1 inhibits neointimal hyperplasia in a rabbit vein graft model.

OBJECTIVE: Inflammation is a key driver of excessive neointimal hyperplasia within vein grafts. Recent work demonstrates that specialized proresolving lipid mediators biosynthesized from omega-3 polyunsaturated fatty acids, such as resolvin D1 (RvD1), actively orchestrate the process of inflammation resolution. We investigated the effects of local perivascular delivery of RvD1 in a rabbit vein graft model. METHODS: Ipsilateral jugular veins were implanted as carotid interposition grafts through an anastomotic cuff technique in New Zealand white rabbits (3-4 kg; N = 80). RvD1 (1 µg) was delivered to the vein bypass grafts in a perivascular fashion, using either 25% Pluronic F127 gel (Sigma-Aldrich, St. Louis, Mo) or a thin bilayered poly(lactic-co-glycolic acid) (PLGA) film. No treatment (bypass only) and vehicle-loaded Pluronic gels or PLGA films served as controls. Delivery of RvD1 to venous tissue was evaluated 3 days later by liquid chromatography-tandem mass spectrometry. Total leukocyte infiltration, macrophage infiltration, and cell proliferation were evaluated by immunohistochemistry. Elastin and trichrome staining was performed on grafts harvested at 28 days after bypass to evaluate neointimal hyperplasia and vein graft remodeling. RESULTS: Perivascular treatments did not influence rates of graft thrombosis (23%), major wound complications (4%), or death (3%). Leukocyte (CD45) and macrophage (RAM11) infiltration was significantly reduced in the RvD1 treatment groups vs controls at 3 days (60%-72% reduction; P < .01). Cellular proliferation (Ki67 index) was also significantly lower in RvD1-treated vs control grafts at 3 days (40%-50% reduction; P < .01). Treatment of vein grafts with RvD1-loaded gels reduced neointimal thickness at 28 days by 61% vs bypass only (P < .001) and by 63% vs vehicle gel (P < .001). RvD1-loaded PLGA films reduced neointimal formation at 28 days by 50% vs bypass only (P < .001). RvD1 treatment was also associated with reduced collagen deposition in vein grafts at 28 days. CONCLUSIONS: Local perivascular delivery of RvD1 attenuates vein graft hyperplasia without associated toxicity in a rabbit carotid bypass model. This effect appears to be mediated by both reduced leukocyte recruitment and decreased cell proliferation within the graft. Perivascular PLGA films may also impart protection through biomechanical scaffolding in this venous arterialization model. Our studies provide further support for the potential therapeutic role of specialized proresolving lipid mediators such as D-series resolvins in modulating vascular injury and repair.

Evaluating intimal hyperplasia under clinical conditions.

OBJECTIVES: Open arterial revascularization using venous segments is frequently associated with the development of intimal hyperplasia (IH), leading to severe restenosis and graft failure. The lack of treatment to prevent this pathology is a major problem. Therefore, we generated a new porcine model, which closely mimics the clinical development of human IH, to test the therapeutic potential of candidate drugs. METHODS: A patch of jugular vein was sutured to the right common carotid artery of pigs, to expose the vein to haemodynamic conditions of the arterial bed. Four weeks after surgery, the operated vessels which received no further treatment (the control group) were compared with (i) contralateral, non-operated vessels (the healthy group); (ii) vessels of pigs that received a perivascular application of a drug-free microparticle gel (the placebo group) and (iii) vessels of pigs that perioperatively received the same gel loaded with 10-mg atorvastatin (the atorvastatin group). RESULTS: When compared with non-operated vessels, all operated segments displayed a sizable IH which was thicker in the venous patch than in the host artery. These alterations were associated with a thickening of the intima layer of both vessels in the absence of inflammation. The intima/media ratio has been significantly increased by 2000-fold in the vein patches. Perivascular application of atorvastatin did not prevent IH formation. However, the drug increased the adventitial neovascularization in the operated vessels. CONCLUSIONS: The novel porcine model allows for monitoring IH formation under haemodynamic conditions which mimic clinical situations. It should facilitate the screening of innovative treatments to prevent restenosis.

Chlorhexidine-coated peripherally inserted central catheters reduce fibroblastic sleeve formation in an in vivo ovine model.

PURPOSE:: This study compared an antimicrobial and anti-thrombogenic peripherally inserted central catheter treated with a chlorhexidine-based technology, a peripherally inserted central catheter with bulk distributed fluoro-oligomers, and a poly 2-methoxyethyl acrylate-based peripherally inserted central catheter to an untreated peripherally inserted central catheter (control) in an ovine model at 14 and 30 days post-implant. METHODS:: One of four types of peripherally inserted central catheters was surgically implanted into the left jugular vein of each of 18 sheep for 14 or 30 days. Blood analysis consisted of complete blood counts, serum chemistries, and coagulation (fibrinogen, prothrombin time, and partial thromboplastin time) profiles. Sheep were sacrificed to examine the vein and thorax. Histological analysis was performed on serial catheter sections using standard microscopy on hematoxylin and eosin-stained tissues. RESULTS:: All catheters developed fibroblastic sleeves at both 14 and 30 days. The chlorhexidine-peripherally inserted central catheter showed a 64% lower mean fibroblastic sleeve weight and a 66% shorter mean fibroblastic sleeve length compared to the untreated control at 14 days. By 30 days, compared to untreated control, the chlorhexidine-peripherally inserted central catheter showed 81% lower mean fibroblastic sleeve weight with 75% shorter mean fibroblastic sleeve length, the fluoro-oligomer-peripherally inserted central catheter showed 54% lower mean sheath weight with 40% shorter mean fibroblastic sleeve length, and the poly 2-methoxyethyl acrylate-peripherally inserted central catheter had 41% lower mean fibroblastic sleeve weight with 57% lower fibroblastic sleeve length. CONCLUSION:: Among the three anti-thrombogenic peripherally inserted central catheter technologies, the chlorhexidine-peripherally inserted central catheter had the smallest fibroblastic sleeves, followed by the fluoro-oligomer-peripherally inserted central catheter, poly 2-methoxyethyl acrylate-peripherally inserted central catheter, and control peripherally inserted central catheter.

In search of the best xenogeneic material for a paediatric conduit: an experimental study.

OBJECTIVES: The development of calcification-resistant bioprosthetic materials is a very important challenge for paediatric surgery. The subcutaneous implantation in rats is the well-known first-stage model for this kind of research. Using this model, we aimed to compare calcification of the porcine aortic wall and bovine pericardium and jugular vein wall cross-linked with glutaraldehyde (GA) and ethylene glycol diglycidyl ether (DE). We also determined the efficacy of DE-preserved tissue modification with 2-(2-carboxyethylamino)ethylidene-1,1-bisphosphonic acid (CEABA). METHODS: Three groups of each biomaterial were evaluated: GA-treated, DE-treated and DE + CEABA-treated. The microstructure of non-implanted biomaterials was assessed by light microscopy after Picro Mallory staining; the phosphorus content of the DE and DE + CEABA samples was assessed by atomic emission spectrometry. Samples were implanted subcutaneously into young rats for 10 and 60 days. The explant end-point included quantitative calcification assessment by atomic absorption spectrophotometry and light microscopy examination after von Kossa staining. RESULTS: All GA-treated biomaterials had a high calcium-binding capacity (>100 µg/mg dry tissue). DE preservation decreased the vein wall and pericardium calcium content by 4- and 40-fold, respectively, but was ineffective for the aortic wall. The calculated CEABA content was almost equal in the vein wall and pericardium (17.7 and 18.5 µM/g) and slightly less in the aortic wall (15 µM/g) (P = 0.011). CEABA effectively reduced mineralization in the DE aortic wall and DE pericardium to 10.1 (7.8-21.1) and 0.95 (0.57-1.38) µg/mg but had no effect in the DE vein wall. Mineralization in the GA- and DE-treated aortic and vein walls was predominantly associated with elastin. CEABA modification decreased elastin calcification but did not block it completely. CONCLUSIONS: Each xenogeneic material requires individual anticalcification strategy. DE + CEABA pretreatment demonstrates a high mineralization-blocking efficacy for the bovine pericardium and should be employed to further develop the paediatric pericardial conduit. Aortic wall calcification cannot be blocked completely using this strategy.

Autologous fat transplants to deliver glitazone and adiponectin for vasculoprotection.

The insulin sensitizing glitazone drugs, rosiglitazone (ROS) and pioglitazone (PGZ) both have anti-proliferative and anti-inflammatory effects and induce adipose tissue (fat) to produce the vaso-protective protein adiponectin. Stenosis due to intimal hyperplasia development often occurs after placement of arteriovenous synthetic grafts used for hemodialysis. This work was performed to characterize the in vitro and in vivo effects of ROS or PGZ incorporation in fat and to determine if fat/PGZ depots could decrease vascular hyperplasia development in a porcine model of hemodialysis arteriovenous graft stenosis. Powdered ROS or PGZ (6-6000µM) was mixed with fat explants and cultured. Drug release from fat was quantified by HPLC/MS/MS, and adiponectin and monocyte chemotactic protein-1 (MCP-1) levels in culture media were measured by ELISA. The effect of conditioned media from the culture of fat with ROS or PGZ on i) platelet-derived growth factor-BB (PDGF-BB)-stimulated proliferation of human venous smooth muscle cells (SMC) was measured by a DNA-binding assay, and ii) lipopolysaccharide (LPS)-induced human monocyte release of tumor necrosis factor-alpha (TNFα) was assessed by ELISA. In a porcine model, pharmacokinetics of PGZ from fat depots transplanted perivascular to jugular vein were assessed by HPLC/MS/MS, and retention of the fat depot was monitored by MRI. A porcine model of synthetic graft placed between carotid artery and ipsilateral jugular vein was used to assess effects of PGZ/fat depots on vascular hyperplasia development. Both ROS and PGZ significantly induced the release of adiponectin and inhibited release of MCP-1 from the fat. TNF production from monocytes stimulated with LPS was inhibited 50-70% in the presence of media conditioned by fat alone or fat and either drug. The proliferation of SMC was inhibited in the presence of media conditioned by fat/ROS cultures. Fat explants placed perivascular to the external jugular vein were retained, as confirmed by MRI at one week after placement. PGZ was detected in the fat depot, in the external jugular vein wall and in adjacent tissue at clinically relevant levels, whereas levels in plasma were below detection. External jugular vein exposed to fat incorporated with PGZ had increased adiponectin expression compared to vein exposed to fat alone. However, the development of hyperplasia within the arteriovenous synthetic grafts was unchanged by treatment with fat/PGZ depots compared to no treatment.

Effects of Shenfu Injection () on cerebral metabolism in a porcine model of cardiac arrest.

OBJECTIVE: To investigate the effects of Shenfu Injection (, SFI) on cerebral metabolism in a porcine model of cardiac arrest (CA). METHODS: Thirty Wuzhishan minipigs were randomly assigned to the control group (n=6), epinephrine group (EP group, n=12) and Sfigroup (n=12). After 8 min of untreated ventricular fifibrillation (VF), pigs in the EP group or Sfigroup were administered with either EP (0.02 mg/kg) or Sfi(1.0 mL/kg), respectively. After successful resuscitation, cerebrospinal fluid (CSF) levels of glucose, pyruvate, lactate, glutamate and glycerol were measured at 1, 6, 12 and 24 h after recover from spontaneous circulation (ROSC). In addition, neurologic defificit score (NDS) was calculated at 24 h after ROSC. Surviving pigs were killed at 24 h after ROSC, and the brain tissue was obtained for ultra-microstructure examination. RESULTS: Compared with the EP group, CSF glucose and pyruvate levels were higher (all P<0.01), and lactate levels were lower in the Sfigroup (P<0.01). Meanwhile, CSF glutamate and glycerol levels in the Sfigroup were lower in comparison to the EP group (all P<0.05). In addition, Sfidecreased NDS at 24 h after ROSC (P<0.01), and alleviated the histopathological damage of the brain. CONCLUSIONS: Sficould alleviate brain injury after CA, which may be associated with improving cerebral metabolism.

Use of Brilliant Blue FCF during vein graft preparation inhibits intimal hyperplasia.

BACKGROUND: Intimal hyperplasia remains the primary cause of vein graft failure for the 1 million yearly bypass procedures performed using human saphenous vein (HSV) grafts. This response to injury is caused in part by the harvest and preparation of the conduit. The use of Brilliant Blue FCF (FCF) restores injury-induced loss of function in vascular tissues possibly via inhibition of purinergic receptor signaling. This study investigated whether pretreatment of the vein graft with FCF prevents intimal hyperplasia. METHODS: Cultured rat aortic smooth muscle cells (A7r5) were used to determine the effect of FCF on platelet-derived growth factor-mediated migration and proliferation, cellular processes that contribute to intimal hyperplasia. The effectiveness of FCF treatment during the time of explantation on preventing intimal hyperplasia was evaluated in a rabbit jugular-carotid interposition model and in an organ culture model using HSV. RESULTS: FCF inhibited platelet-derived growth factor-induced migration and proliferation of A7r5 cells. Treatment with FCF at the time of vein graft explantation inhibited the subsequent development of intimal thickening in the rabbit model. Pretreatment with FCF also prevented intimal thickening of HSV in organ culture. CONCLUSIONS: Incorporation of FCF as a component of vein graft preparation at the time of explantation represents a potential therapeutic approach to mitigate intimal hyperplasia, reduce vein graft failure, and improve outcome of the autologous transplantation of HSV.

Liposomal prednisolone inhibits vascular inflammation and enhances venous outward remodeling in a murine arteriovenous fistula model.

Arteriovenous fistulas (AVF) for hemodialysis access have a 1-year primary patency rate of only 60%, mainly as a result of maturation failure that is caused by insufficient outward remodeling and intimal hyperplasia. The exact pathophysiology remains unknown, but the inflammatory vascular response is thought to play an important role. In the present study we demonstrate that targeted liposomal delivery of prednisolone increases outward remodeling of the AVF in a murine model. Liposomes accumulate in the post-anastomotic area of the venous outflow tract in which the vascular pathology is most prominent in failed AVFs. On a histological level, we observed a reduction of lymphocytes and granulocytes in the vascular wall. In addition, a strong anti-inflammatory effect of liposomal prednisolone on macrophages was demonstrated in vitro. Therefore, treatment with liposomal prednisolone might be a valuable strategy to improve AVF maturation.

Therapeutic Drug Monitoring of Vancomycin in Dermal Interstitial Fluid Using Dissolving Microneedles.

OBJECTIVE: To design an alternative painless method for vancomycin (VCM) monitoring by withdrawing interstitial fluid (ISF) the skin using dissolving microneedles (DMNs) and possibly replace the conventional clinical blood sampling method. METHODS: Male Wistar rats were anesthetized with 50 mg/kg sodium pentobarbital. Vancomycin at 5 mg/mL in saline was intravenously administered via the jugular vein. ISF was collected from a formed pore at 15, 30, 45, 60, 75, 90, and 120 min after the DMNs was removed from the skin. In addition, 0.3 mL blood samples were collected from the left femoral vein. RESULTS: The correlation between the plasma and ISF VCM concentrations was significantly strong (r = 0.676, p < 0.05). Microscopic observation of the skin after application of the DMNs demonstrated their safety as a device for sampling ISF. CONCLUSION: A novel monitoring method for VCM was developed to painlessly determine concentrations in the ISF as opposed to blood sampling.

Nitric Oxide Resistance Reduces Arteriovenous Fistula Maturation in Chronic Kidney Disease in Rats.

BACKGROUND: Autologous arteriovenous (AV) fistulas are the first choice for vascular access but have a high risk of non-maturation due to insufficient vessel adaptation, a process dependent on nitric oxide (NO)-signaling. Chronic kidney disease (CKD) is associated with oxidative stress that can disturb NO-signaling. Here, we evaluated the influence of CKD on AV fistula maturation and NO-signaling. METHODS: CKD was established in rats by a 5/6th nephrectomy and after 6 weeks, an AV fistula was created between the carotid artery and jugular vein, which was followed up at 3 weeks with ultrasound and flow assessments. Vessel wall histology was assessed afterwards and vasoreactivity of carotid arteries was studied in a wire myograph. The soluble guanylate cyclase (sGC) activator BAY 60-2770 was administered daily to CKD animals for 3 weeks to enhance fistula maturation. RESULTS: CKD animals showed lower flow rates, smaller fistula diameters and increased oxidative stress levels in the vessel wall. Endothelium-dependent relaxation was comparable but vasorelaxation after sodium nitroprusside was diminished in CKD vessels, indicating NO resistance of the NO-receptor sGC. This was confirmed by stimulation with BAY 60-2770 resulting in increased vasorelaxation in CKD vessels. Oral administration of BAY 60-2770 to CKD animals induced larger fistula diameters, however; flow was not significantly different from vehicle-treated CKD animals. CONCLUSIONS: CKD induces oxidative stress resulting in NO resistance that can hamper AV fistula maturation. sGC activators like BAY 60-2770 could offer therapeutic potential to increase AV fistula maturation.

Perivenous application of cyanoacrylate tissue sealants reduces intimal and medial thickening of the vein graft and inflammatory responses in a rabbit model of carotid artery bypass grafting.

OBJECTIVES: Effective therapies to prevent vein graft failure after coronary artery bypass grafting (CABG) are still lacking. α-Cyanoacrylate (α-CA, 99% n-octyl-α-cyanoacrylate + n-butyl-α-cyanoacrylate) has been increasingly used as a tissue sealant for wound closure because of its bacteriostatic, biodegradable and haemostatic properties. As a strong tissue adhesive, α-CA might prevent an arterial circulation-induced mechanical stretch on vein graft to attenuate intimal hyperplasia. Here, we investigated the effects of perivenous application of α-CA on the vein graft in a rabbit model of carotid artery bypass grafting. METHODS: Healthy New Zealand white rabbits were randomized into no graft, graft or graft + α-CA group (n = 10 per group). Rabbit carotid artery was bypassed with the jugular vein. α-CA sealants were sprayed on the entire jugular graft including both anastomotic sites after completion of anastomoses. Blood flow parameters and histological characteristics of the vein grafts including vessel wall thickness, number of medial elastic lamina and proliferation index were evaluated 4 weeks after the surgery. The mRNA or protein levels of proinflammatory factors, chemokine (C-C motif) ligand-2 (CCL-2) and tumour necrosis factor-α (TNF-α) were measured 4 weeks after the operation by quantitative reverse transcription polymerase chain reaction or enzyme-linked immunosorbent assay. RESULTS: Compared with the untreated vein grafts at Week 4 after the operation, the α-CA spray significantly improved graft flow (39.4 ± 1.5 vs 27.8 ± 2.9 ml/min, P < 0.01), attenuated intimal and medial thickening (116.3 ± 1.0 vs 159.7 ± 0.9 µm, P < 0.01), reduced anti-proliferating cell nuclear antigen proliferation index of the vein grafts (15.0 ± 0.4 vs 23.6 ± 0.4%, P < 0.01), decreased the mRNA levels of plasminogen activator inhibitor-1 and CCL-2, and reduced the serum levels of TNF-α (92.9 ± 1.7 vs 102.7 ± 1.8 pg/ml, P < 0.01). CONCLUSION: Perivenous application of α-CA sealants exerts short-term beneficial effects on the vein graft and reduces inflammatory responses in a rabbit model of carotid artery bypass grafting. Long-term effects of α-CA on vein graft remodelling and the clinical significance of α-CA in CABG remain to be determined in future studies.

Dipeptidyl peptidase 4 inhibitor reduces intimal hyperplasia in rabbit autologous jugular vein graft under poor distal runoff.

BACKGROUND: Dipeptidyl peptidase 4 inhibitors are widely used in patients with type 2 diabetes mellitus to accomplish glycemic control through an increase in the blood glucagon-like peptide 1 (GLP-1) concentration. These agents also inhibit vascular inflammation (eg, in atherosclerosis). This study was undertaken to determine whether and how vildagliptin (a potent dipeptidyl peptidase 4 inhibitor) might reduce intimal hyperplasia in vein grafts. METHODS: Twelve rabbits were randomly divided into two groups; one group received vildagliptin orally (10 mg/kg/d; n = 6), whereas the control group (n = 6) did not. Vildagliptin administration was started 7 days before rabbits underwent interposition reversed autologous jugular vein grafting and ended at graft harvesting (28 days after the operation). Histochemical changes in the vascular wall were examined, as were changes in the acetylcholine-induced effects on the endothelial Ca(2+) concentration ([Ca(2+)]i) and endothelium-dependent relaxation. RESULTS: Under fasting conditions, vildagliptin increased the plasma GLP-1 concentration, without affecting plasma glucose or insulin. Acetylcholine induced endothelium-dependent relaxation only in the vildagliptin group, and this was blocked by the nitric oxide synthase inhibitor N(ω)-nitro-l-arginine. Acetylcholine did not modify the endothelial [Ca(2+)]i in either the control or vildagliptin group. Intimal hyperplasia was significantly less in the vildagliptin group (0.11 ± 0.02 mm, n = 5) than in the controls (0.31 ± 0.06 mm, n = 4; P < .01). CONCLUSIONS: Vildagliptin increased the plasma GLP-1 concentration. It also enhanced acetylcholine-induced [Ca(2+)]i-independent endothelial nitric oxide release and reduced vein graft intimal hyperplasia, independently of any glycemic control action.

[Intracranial hypertension and jugular vein thrombosis]. / Intrakranielle Hypertension und Jugularvenenthrombose.

BACKGROUND: Pseudotumor cerebri is an idiopathic increase in intracranial pressure, which commonly affects obese women of fertile age. The diagnostic criteria according to the guidelines of the German Society for Neurology are increased cerebrospinal fluid (CSF) pressure, symptoms of increased CSF pressure, normal results of CSF examination, no relevant medication and a lack of structural and vascular lesions in magnetic resonance imaging (MRI). CASE REPORT: This article presents the case of a 39-year-old male patient who presented at hospital with visual obscuration and recently occurred double vision. Except for a recently diagnosed thrombosis of the left jugular vein of unknown origin, there was nothing else of note in the medical history. Biomicroscopic examination showed papilledema with hemorrhages and cotton wool spots. The CSF opening pressure was initially > 50 cmH2O. During therapy by lumbar puncture (three times), oral carbonic anhydrase inhibitors and loop diuretics, the abducens nerve palsy and papilledema receded. Anticoagulation therapy (initially with coumarin derivatives, then with low molecular weight heparins) was unsuccessful in eliminating the thrombosis of the jugular vein. Surgical intervention was not recommended by the vascular surgeons. CONCLUSION: This case report demonstrates the unusual combination of (idiopathic) intracranial hypertension and thrombosis of the jugular vein, which occurred spontaneously and without any detectable coagulation disorders.

Prevention of Venous Neointimal Hyperplasia by a Multitarget Receptor Tyrosine Kinase Inhibitor.

BACKGROUND/AIMS: Venous neointimal hyperplasia (NH) is the predominant cause of stenosis in hemodialysis arteriovenous grafts (AVG), but there is currently no clinically used therapy to prevent NH. METHODS: A porcine AVG model was used to identify potential pharmacological targets to prevent NH. Sunitinib, a broad-spectrum tyrosine kinase inhibitor, was examined as a potential anti-NH drug utilizing in vitro and ex vivo models. RESULTS: In an in vivo porcine model, PDGF, VEGF and their receptors PDGFR-α and VEGFR-2 were upregulated at the venous anastomosis within 2 weeks after AVG placement, with NH development by 4 weeks. Sunitinib inhibited PDGF-stimulated proliferation, migration, phosphorylation of MAPK and PI3K/Akt proteins and changes in the expression of cell-cycle regulatory proteins in vascular smooth-muscle cells as well as VEGF-stimulated endothelial cell proliferation in vitro. In an ex vivo model, significant NH was observed in porcine vein segments perfused for 12 days under pathological shear stress. Sunitinib (100 nM) inhibited NH formation, with the intima-to-lumen area ratio decreasing from 0.45 ± 0.25 to 0.04 ± 0.02 (p < 0.05) with treatment. CONCLUSION: These findings demonstrate sunitinib to be a potential NH-preventive drug as well as the utility of an ex vivo model to investigate pharmacotherapies under pathophysiological flow conditions.