Endothelial cell injury in human saphenous veins after manipulation and tweezer grasping

Eight pieces of human saphenous vein were subjected to tweezer grasping and digital handling. The pressure between the tweezer branches was estimated to be 2 x 10(5) Pa. The resulting endothelial injury was studied by light microscopy (LM), scanning (SEM) and transmission electron microscopy (TEM). Tweezer-grasping resulted in focal destruction of the endothelial lining, whereas digital handling (rolling the vein 3-4 times between the gloved fingers) resulted in minor morphological endothelial cell alterations.     

Endothelial cell injury in human saphenous veins following use of a circular valvulotome.

With increasing use of nonreversed saphenous vein as a bypass conduit (either in-situ or translocated) several techniques of valve ablation are used. The present study was designed to assess the extent of endothelial damage caused by a circular blade valvulotome.     

The influence of harvesting technique on endothelial preservation in saphenous veins.

To study optimal conditions of preparation of saphenous veins as coronary artery bypass grafts, segments of saphenous veins were obtained from 29 consecutive patients undergoing coronary artery bypass grafting. The saphenous vein segments were divided into three groups. In Group I, 10 saphenous vein segments were harvested using a "no-touch" technique without any other preparation aids. In Group II, 10 saphenous vein segments were removed while distended at 70-120 mm Hg with a balanced pH electrolyte solution at 37 degrees C. In Group III, consisting of 10 saphenous vein segments, nitroglycerin (1 microgram/ml) was added to the distending solution used in Group II. Samples of saphenous vein were assessed in a blind study using light and scanning electron microscopy to estimate endothelial cell preservation by the three harvest techniques. Saphenous veins receiving only a no-touch dissection technique without distention solution (Group I) revealed significantly better endothelial preservation (P less than 0.005). The administration of distention solution alone, or with nitroglycerin, to saphenous veins in situ using our operative technique during harvest does not appear to protect endothelial-integrity and may be harmful.     

Tetrahydrobiopterin improves endothelial function in human saphenous veins

OBJECTIVES: Diminished production of nitric oxide has been linked to saphenous vein endothelial dysfunction. Tetrahydrobiopterin is an obligate cofactor for the oxidation of L -arginine by nitric oxide synthase in the production of nitric oxide by endothelial cells. The objective of the present study was to examine whether the exogenous addition of tetrahydrobiopterin improves endothelial function in saphenous veins from patients undergoing coronary artery bypass graft operations. METHODS: Vascular segments of saphenous veins were obtained from 17 patients undergoing elective coronary artery bypass grafting, and in vitro endothelium-dependent and endothelium-independent responses to acetylcholine and sodium nitroprusside were assessed. Isometric dose-response curves were constructed in precontracted rings in the presence and absence of tetrahydrobiopterin (0.1 mmol/L) with the use of the organ bath apparatus. The percentages of maximum relaxation and sensitivity were compared between interventions. RESULTS: Acetylcholine caused dose-dependent endothelium-mediated relaxation in saphenous veins. In the presence of tetrahydrobiopterin, acetylcholine-induced relaxation was significantly augmented (percentage maximum relaxation, 16.8% +/- 2.9% vs control 7.5% +/- 1.8%; P =.003) without an effect on agonist sensitivity. These effects were endothelium-specific because endothelium-independent responses to sodium nitroprusside were preserved. CONCLUSIONS: These data uncover beneficial effects of acute tetrahydrobiopterin addition on endothelial function in human vessels. Because endothelial dysfunction has been implicated in the development of graft failure, studies aimed at chronic delivery of tetrahydrobiopterin would be useful in determining the contribution of this cofactor toward saphenous vein atherosclerosis.     

Viability of long-term cryopreserved human saphenous veins

The feasibility of maintaining long-term viability of human venous allografts by cryopreservation has been investigated. Segments of vein were obtained from 85 patients undergoing a stripping operation for varicose veins. The venous segments were immersed in a dimethylsulfoxide 15% solution, deep frozen at -196 degrees C in liquid nitrogen and preserved for a duration of 1 week to 24 months. Light microscopy (n = 126) failed to demonstrate striking differences between control veins and any of the cryopreserved veins. The types of damage observed at scanning electron microscopy included endothelial cell separation, endothelial cell loss, exposed basement membrane and exposed fibrillar collagen, which were graded on a scale. The score for short term (less than 3 weeks) stored veins was 8.1 +/- 0.9 (mean +/- SEM) and did not differ from the long-term (greater than 10 weeks) stored veins score (6.3 +/- 1.0, p NS). The tissue enzymes LDH, GOT, GPT, CPK were measured in the frozen vein groups (n = 115) after thawing to room temperature. Cryopreservation did not alter any of the tissue enzymes measured when compared to controls. Endothelial fibrinolytic activity (FA) of 58 venous segments cryopreserved for a mean duration of 20 months was 6136.4 +/- 292.1 Tissue Activator Units (TAU) and did not differ from FA of 11 controls (5989.1 +/- 696.8 TAU). Synthesis of 6-Keto-PGF1-alpha-2, a stable breakdown product of PGI2, measured in 10 venous segments cryopreserved for 10 months, was significantly higher than in 13 veins stored in saline for 12 hours at 4 degrees C (2.8 +/- 0.4 vs 0.4 +/- 0.1 PG ml-1mg-1min-1, respectively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Stripping operation with preservation of the calf saphenous veins for primary varicose veins: hemodynamic evaluation

PURPOSE: To study early changes in venous hemodynamics in stripping operation with preservation of the calf saphenous veins. PATIENTS AND METHODS: From October 1999 to December 2000, 110 extremities of 73 patients were treated for primary varicose veins. Based on preoperative ascending venography, 40 extremities underwent the groin-to-knee stripping of the GSV, 20 underwent the proximal division of the LSV, and 50 received combinations of both surgeries. To evaluate venous hemodynamic changes, air plethysmography was performed before operation and 7-14 days after operation. RESULTS: The venous volume, venous filling index and residual volume fraction were improved after surgery, but the ejection fraction did not change. The overall incidence of nerve injury was 4.5% (five limbs). CONCLUSIONS: In stripping operations, the preservation of the calf saphenous veins, which is shown to be advantageous in reducing saphenous or sural nerve injuries, does not adversely affect early venous hemodynamic improvement.     

Paclitaxel treatment reduces neointimal hyperplasia in cultured human saphenous veins

Background: Paclitaxel exerts antiproliferative properties by stabilizing microtubuli of the cell. The substance is in clinical use for drug-eluting coronary stents. We aimed to test the hypothesis that paclitaxel treatment can reduce neointimal hyperplasia in cultured human saphenous veins and thus might be useful for local pharmacologic treatment of vein grafts prior to coronary artery bypass grafting (CABG). Methods: The remnants of saphenous veins from 13 patients undergoing CABG were collected. The development of neointimal hyperplasia was induced using an established organ culture model (incubation time 2 weeks). In the treatment group, paclitaxel was added to the culture medium at different concentrations. Results: Veins treated with 1 μmol/l paclitaxel showed a median increase of intimal thickness of 2 μm (range −76 to 46) above baseline levels, whereas untreated control veins increased by 15 μm (range −3 to 142) (p = 0.022). Treatment with 10 μmol/l paclitaxel resulted in a lower intimal thickness growth of 1 μm (range −82 to 212) above baseline levels (p = 0.035 vs controls). Treatment with 25 or 50 μmol/l paclitaxel did not further inhibit intimal hyperplasia. The neointimal amount of the contractile protein smooth muscle actin (SMA) in paclitaxel 1 μmol/l treated veins was significantly higher than baseline values (p = 0.037). The cytoskeletal protein desmin was predominant in the media, whereas it was less frequently found in the intima, and we observed no difference between controls and paclitaxel treated veins. The proliferation marker ki-67 was occasionally present in the circumferential media, whereas it was almost absent in both the (inner) longitudinal media and the intima. Elastic fibers were present in the media and intima before and after organ culture without significant differences between the groups. Collagen fibers (Masson's trichrome) were found abundantly (80%) in the inner longitudinal media, less commonly (20%) in the outer circumferential media, and they were absent in the intima without difference between the groups. Conclusion: Local paclitaxel treatment reduces neointimal hyperplasia in cultured human saphenous veins, without changing the amount of elastic or collagen fibers. Paclitaxel treatment leads to an increased amount of the contractile protein SMA and thus might have a therapeutic potential for the prevention of vein graft disease.     

Effects of vasoactive agents in healthy and diseased human saphenous veins

Purpose: Smooth muscle reactivity is one of the factors involved in the pathogenesis of varicose veins. We investigated the myotropic effects of the 3 main vasoconstrictor agents—norepinephrine (NE), angiotensin II (Ang II), and endothelin-1 (ET-1)—in isolated human saphenous veins. Methods: Human saphenous veins were collected from 23 patients with primary chronic venous insufficiency who underwent elective varicose vein resections and who were stratified into the following 3 groups: group 1, 7 patients in clinical class 2; group 2, 9 patients in clinical classes 3 and 4; and group 3, 7 patients in clinical classes 5 and 6. Moreover, 6 patients who underwent arterial bypass grafting procedures represented the control group. The tissues were suspended in organ baths that contained Krebs solution, and their mechanical responses were measured isometrically. The cumulative concentration–response curves to Ang II, NE, and ET-1 were performed at 90-minute intervals in each tissue. Results: In the control tissues, NE, Ang II, and ET-1 induced concentration-dependent contractions with apparent affinities (pEC₅₀, the negative logarithm to base 10 of the molar concentration of the agonist, which produces the 50% of the maximal effect) and maximal effects (maximum effect, g of contraction) that were equal to 7.06 ± 0.23, 8.53 ± 0.34, 7.63 ± 0.10, and 2.21 ± 0.33, 1.65 ± 0.31, 2.60 ± 0.77, respectively. Two main findings were evident in comparison of varicose veins with control tissues. First, the maximum effect that was evoked by all of the stimulants was reduced progressively with the increasing severity of the disease, which raised the third group to statistical significance for both NE and Ang II (P < .05). Second, a marked reduction of Ang II apparent affinity was already evident in tissues that were taken from patients in an early stage of the disease (P < .05). Conclusion: The demonstration of a significant reduction in Ang II and NE contractile activities and the important reduction of that of ET-1 in the diseased veins as compared with the control tissues extends the previous observations regarding the impairment of smooth muscle contractility in primary chronic venous insufficiency. Moreover, the dramatic reduction of Ang II affinity, which appears in an early stage of the disease, supports the hypothesis that such abnormality within the venous wall could play a role in the pathogenesis of primary varicose vein disease. (J Vasc Surg 1998;28:855-61.)     

人大隐静脉培养过程中血管紧张素转换酶mRNA的变化

目的　研究人大隐静脉器官培养过程中血管紧张素转换酶 (ACE)mRNA表达的变化。方法　用内参照逆转录 聚合酶链反应 (RT PCR)研究大隐静脉器官培养 1 4d后ACEmRNA的表达。结果　对照组静脉内膜厚度为 (3 .5± 2 .0 ) μm ,ACEmRNA水平为 0 .347± 0 .1 58;培养 1 4d后内膜厚度为 (47.0± 9.3) μm ,ACEmRNA水平 0 .777± 0 .1 4 3 ,两组差异有显著性。 结论　人大隐静脉器官培养过程中ACEmRNA显著增高     

Primary great saphenous varicose veins revisited

Our knowledge of the prevalence, pathogenesis, and treatment of primary great saphenous varicose veins has been reviewed. There is now evidence that potentially correctable environmental factors contribute importantly to the development of primary varicose veins, but what these factors are is not known. It is suggested that the evidence that incompetence of the venous valves at and above the saphenofemoral junction initiates the development of primary great saphenous varicose veins is scientifically weak. There are a number of questions about the treatment of primary varicose veins that have scarcely been asked, far less answered. The case is argued for microepidemiological studies of the prevalence of primary varicose veins, for studies to test more rigorously the valve hypothesis of their causation, and for more prospective, long-term, clinical trials of treatment to be undertaken.

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Resumen Se revisa el estado del conocimiento actual sobre la prevalencia, patogénesis, y tratamiento sobre las várices primarias del sistema safeno mayor. Existe evidencia indicativa de que factores ambientales potecialmente corregibles contribuyen en forma importante al desarrollo de las várices primarias, pero se desconoce realmente cuales son tales factores. Se sugiere que el postulado sobre la incompetencia valvular venosa a nivel de, y por encima de la desembocadura safenofemoral, como factor que inicia el desarrollo de várices del sistema safeno mayor, es débil desde el punto de vista científico. Surge un numéro considerable de interrogantes sobre el tratemiento de las várices primarias, los cuales escasamente han sido planteados y, mucho me nos, respondidos en el pasado. Aparece evidente la conveniencia de emprender estudios microepidemiológicos sobre la incidencia de várices primarias, estudios orientados a comprobar en forma más rigurosa la hipótesis sobre la alteración valvular como factor causante, y ensayos terapéuticos prospectivos a largo plazo.

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Résumé Notre connaissance de la fréquence de la pathogénie et du traitement des varices primitives de la grande veine saphène a été réétudiée. Il est évident maintenant que des facteurs prédisposants susceptibles d'Être corrigés contribuent considérablement à l'apparition des varices primitives mais ils ne sont pas parfaitement connus. Il semble que l'incompétence des valves veineuses au niveau et au-dessus de la jonction saphéno-fémorale qui serait à l'origine du développement des varices primitives de la grande saphène à une base scientifique discutable. De nombreuses questions concernant le traitement de ces varices ont été soulevées mais n'ont pas reÇu de réponse précise. Il est nécessaire de procéder à des études micro-épidémiologiques concernant la fréquence des varices primitives, d'avoir recours à des méthodes plus rigoureuses pour confirmer l'hypothèse valvulaire de leur origine, et enfin d'entreprendre prospectivement des essais thérapeutiques en appréciant leurs résultats à long terme.

     

Endothelial function can be preserved during cryo-storage of human saphenous vein

Endothelial functional integrity was quantified in human saphenous vein by measurement of stimulated (vortex-mixing) rates of prostacyclin production. Prostacyclin production was not inhibited by dimethylsulphoxide (DMSO), glycerol or sucrose at concentrations normally used for cryopreservation. Rapid freezing followed by storage for 3-4 weeks and thawing of veins pretreated with 15% (v/v) dimethylsulphoxide significantly impaired prostacyclin production. In contrast, slow freezing and thawing in the presence, but not the absence, of DMSO led to complete retention of prostacyclin production. We conclude that endothelial function can be preserved during cryostorage.     

Liposomal entrapment of cefoxitin to improve cellular viability and function in human saphenous veins

Liposomal cefoxitin was prepared and applied to the pretreatment of human saphenous vein (HSV) for implantation. The possible use of liposomal cefoxitin to improve cellular viability and function and to maintain its potential sterilization effect was investigated. Entrapment efficiency and size distribution of liposomal cefoxitin were 75.7% and 652 +/- 75.7 nm, respectively. The weight ratio between cefoxitin and liposome was calculated at 1 : 40.6. When cefoxitin was entrapped with liposome, the released amount of cefoxitin was not affected by temperature conditions (37 degrees C, 25 degrees C, and 4 degrees C). The amount of free cefoxitin present in HSV reached 59% at 0.5 h and gradually decreased with time, while liposomal cefoxitin showed a maximum amount (63%) at 1.5 h, indicating that liposomal cefoxitin seemed to control the initial amount of cefoxitin present in HSV. Liposomal cefoxitin showed better viabilities of whole cells and endothelial cells dissociated from HSV than free cefoxitin and remarkably superior function of endothelial cells, as determined by Griffonia simplicifolia agglutinins-fluorescein isothiocyanate/propidium iodide double-staining methods combined with flow cytometry and endothelial nitric oxide synthase assay, respectively. In terms of sterilization effect, there was no significant difference between liposomal cefoxitin and free cefoxitin. These results suggest that liposomal entrapment of cefoxitin could improve cellular viability and functions and maintain the original sterilization effect.     

Modified inguinal lymphadenectomy for carcinoma of the penis with preservation of saphenous veins: technique and preliminary results

The controversy surrounding the management of patients with invasive carcinoma of the penis and clinically negative nodes is discussed. The rationale, technique and preliminary results of a modified inguinal lymphadenectomy in which the lateral and caudal extents of nodal excision are reduced, and the saphenous veins are preserved also are presented. This modified lymphadenectomy has been performed in 6 patients with invasive carcinoma of the penis or distal urethra without major or troublesome complications.