scholarly journals Wall shear modulation of cytokines in early vein grafts

2004 ◽  
Vol 40 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Zhihua Jiang ◽  
Scott A Berceli ◽  
Chun L Pfahnl ◽  
Lizhen Wu ◽  
Darin Goldman ◽  
...  
Keyword(s):  
Vein Grafts ◽  
Wall Shear ◽  
Shear Modulation

WALL SHEAR AND CIRCUMFERENTIAL STRESS CHANGES IN A PORCINE DOUBLE-LAYER VEIN GRAFT

2011 ◽  
Vol 11 (05) ◽  
pp. 1059-1070 ◽  
Author(s):  
Q. JI ◽  
Y. Q. MEI ◽  
X. S. WANG ◽  
D. W. WUSHA
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Double Layer ◽  
Vein Graft ◽  
Circumferential Stress ◽  
Control Group ◽  
Bypass Grafting ◽  
Venous Bypass ◽  
Vein Grafts ◽  
Wall Shear

This study aimed to evaluate short-term changes of wall shear stress and circumferential stress in a self-designed double-layer vein graft in a porcine vein graft model. In this study, left and right hind femoral arteries of 40 white pigs were randomly divided into an experimental group (double-layer vein graft) and a control group (single-layer vein graft). At one hour and then at one, two and four weeks after venous bypass grafting, sets of ten animals underwent Doppler-ultrasonic and electromagnetic flowmeter examinations to calculate wall shear stress in middle sections of the vein grafts. Then, the vein grafts were excised and subjected to mechanical tests to assess the circumferential stress. As a result, the double-layer vein grafts showed an increase in wall shear stress by 43.5% compared with the control group at one hour after venous bypass grafting. With time wall shear stress gradually increased, the intimal circumferential stress gradually decreased in the two groups. Intimal circumferential stress in the experimental group was significantly lower than that in the control group at each observational time-point. Hence, the double-layer support of the vein graft may have contributed towards a rise in wall shear stress and reduction in circumferential stress in the true vein graft over the four-week period after venous bypass grafting, and thus conferring some protection to the true vein graft.

Abstract 116: Enhanced Systemic Inflammation Results in Loss of Vein Graft Lumen and Augments Adaptation to Increased Wall Shear

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Yong He ◽  
Kerri O’Malley ◽  
Catherine Chang ◽  
Khayree Butler ◽  
Peter Nelson ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Vein Graft ◽  
Fluid Dynamic ◽  
Ct Scanning ◽  
Lumen Area ◽  
Cross Sectional ◽  
Vein Grafts ◽  
Cytokines And Chemokines ◽  
Inflammatory State ◽  
Wall Shear

Introduction: Unlike animal models which are highly reproducible, human vascular remodeling demonstrates marked heterogeneity both within and between patients. Studying human vein grafts (VG), we hypothesize that the local wall shear stress (WSS), modulated by the systemic inflammatory milieu, dictates vascular adaptation and preservation (or loss) of VG lumen. Methods: Following infrainguinal VG placement, 33 patients were evaluated with ultrasound duplex, CT scanning and computational fluid dynamic modeling (at 1 week (1w), 1 month (1m), and 6 months (6m) post-op) to determine the WSS and cross-sectional area at 1 mm intervals along the entire VG. Plasma samples were collected (pre-op, 2 hours, 1 day, 1 week, 1 month) and analyzed for 28 pro- and anti-inflammatory cytokines and chemokines. Results: Regions of reduced shear (< 5 dynes/cm 2 ) demonstrated a loss of VG lumen area in the 1w-1m (-6.5% ± 3.2%) and 1m-6m (-8.2% ± 4.8%) timeframe; elevated shear areas (> 50 dynes/cm 2 ) led to an expansion in lumen area (1w-1m: 27% ± 8%; 1m-6m: 36% ± 14%). Patients with pre- and early post-op elevations in the pro-inflammatory cytokines IL-12, -13, -15 demonstrated enhanced loss of VG lumen between 1 w and 1m ( A ). Increased levels of IL-1b, -2, -3, -4, -6 at 1 month were associated with late reductions in VG lumen area ( B ). In contrast, early elevations in MMP-9, E-selectin, and VCAM-1 were accompanied by enhanced outward remodeling, most prominently in high shear regions ( C , p<0.05). Conclusions: Human VG remodeling are highly responsive to the local WSS, and specific cytokines patterns appear to modulate this process in both early and late vein graft remodeling. Using this information, therapeutic manipulation of the peri-operative inflammatory state may be used to improve VG survival.

Control of Autogenous Vein Grafts Prior to Reimplantation, By Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 106-107
Author(s):  
John H. L. Watson ◽  
John L. Swedo ◽  
M. Vrandecic
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Physiological Saline ◽  
Experimental Conditions ◽  
Vein Grafts ◽  
Arterial Blood ◽  
Saphenous Veins ◽  
Autogenous Vein ◽  
Control Of Parameters ◽  
Post Implantation

The ambient temperature and the nature of the storage fluids may well have significant effects upon the post-implantation behavior of venus autografts. A first step in the investigation of such effects is reported here. Experimental conditions have been set which approximate actual operating room procedures. Saphenous veins from dogs have been used as models in the experiments. After removal from the dogs the veins were kept for two hours under four different experimental conditions, viz at either 4°C or 23°C in either physiological saline or whole canine arterial blood. At the end of the two hours they were prepared for light and electron microscopy. Since no obvious changes or damage could be seen in the veins by light microscopy, even with the advantage of tissue specific stains, it was essential that the control of parameters for successful grafts be set by electron microscopy.

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

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