scholarly journals Artery to vein configuration of arteriovenous fistula improves hemodynamics to increase maturation and patency

2020 ◽  
Vol 12 (557) ◽  
pp. eaax7613
Author(s):  
Hualong Bai ◽  
Nirvana Sadaghianloo ◽  
Jolanta Gorecka ◽  
Shirley Liu ◽  
Shun Ono ◽  
...  
Keyword(s):  
Neointimal Hyperplasia ◽  
Peak Systolic Velocity ◽  
Male Rats ◽  
Secondary Patency ◽  
Hemodialysis Access ◽  
Bilateral Carotid ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Bilateral Carotid Artery

Arteriovenous fistulae (AVF) are the preferred mode of hemodialysis access, but 60% of conventional [vein-to-artery (V-A)] AVF fail to mature, and only 50% remain patent at 1 year. We previously showed improved maturation and patency in a pilot study of the radial artery deviation and reimplantation (RADAR) technique that uses an artery-to-vein (A-V) configuration. Here, we show that RADAR exhibits higher rates of maturation, as well as increased primary and secondary long-term patencies. RADAR is also protective in female patients, where it is associated with decreased reintervention rates and improved secondary patency. RADAR and conventional geometries were compared further in a rat bilateral carotid artery-internal jugular vein fistula model. There was decreased cell proliferation and neointimal hyperplasia in the A-V configuration in male and female animals, but no difference in hypoxia between the A-V and V-A configurations. Similar trends were seen in uremic male rats. The A-V configuration also associated with increased peak systolic velocity and expression of Kruppel-like factor 2 and phosphorylated endothelial nitric oxide synthase, consistent with improved hemodynamics. Computed tomography and ultrasound-informed computational modeling showed different hemodynamics in the A-V and V-A configurations, and improving the hemodynamics in the V-A configuration was protective against neointimal hyperplasia. These findings collectively demonstrate that RADAR is a durable surgical option for patients requiring radial-cephalic AVF for hemodialysis access.

Endothelial nitric oxide synthase (eNOS) mediates neointimal thickness in arteriovenous fistulae with different anastomotic angles in rats

2021 ◽  
pp. 112972982199653
Author(s):  
Hualong Bai ◽  
Shunbo Wei ◽  
Boao Xie ◽  
Zhiwei Wang ◽  
Mingxing Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Nitric Oxide Synthase ◽  
Neointimal Hyperplasia ◽  
Acute Angle ◽  
Obtuse Angle ◽  
Enos Expression ◽  
Arteriovenous Fistulae ◽  
Neointimal Thickness ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Background: It is known that the anastomotic angle can influence neointimal hyperplasia and patency in arteriovenous fistulae (AVF). Endothelial nitric oxide synthase (eNOS) is released from the vascular endothelium and can inhibit neointimal hyperplasia. Therefore, here, we aimed to test the hypothesis that the manipulation of eNOS expression could influence neointimal thickness in a rat AVF model with different anastomosis angles. Methods: Rat carotid artery (inflow, CA) and jugular vein (outflow, JV) AVF were created with acute, blunt, or end-to-end (ETE) anastomosis angles. Aspirin was used to increase eNOS expression in the acute angle group, while N(G)-nitro-L-arginine methyl ester (L-name) was used to decrease eNOS expression in the obtuse angle group. The rats were sacrificed on day 21, and tissues were harvested and analyzed histologically and with immunostaining. Results: A larger anastomosis diameter ( p < 0.016) and smaller neointimal area ( p < 0.01) were observed in the obtuse and end-to-end (ETE) groups compared to in the acute group. In the acute angle group, there were more proliferating cell nuclear antigen (PCNA) and α-actin dual-positive cells ( p < 0.0001) and fewer phospho (p)-eNOS-positive endothelial cells ( p < 0.0001) in the neointima than in the obtuse and ETE angle groups. On treating the acute angle and blunt angle groups with aspirin and L-name, respectively, no significant differences in the neointima/lumen rate were observed ( p = 0.6526) between the groups; however, there were fewer von Willebrand factor (vWF) and p-eNOS dual-positive cells in the obtuse angle group treated with L-name ( p = 0.0045). Conclusions: We demonstrated that eNOS plays an important role in neointimal hyperplasia in AVF with different anastomosis angles; further, eNOS could potentially be used as a therapeutic target in patients with AVF in the future.

Chronic cerebral hypoperfusion in male rats results in sustained HPA activation, and hyperinsulinemia

2021 ◽  
Author(s):  
Theresa A. Lansdell ◽  
Anne M Dorrance
Keyword(s):  
Insulin Resistance ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Male Rats ◽  
Lower Blood Glucose ◽  
Insulin Resistant ◽  
Lower Blood ◽  
Bilateral Carotid ◽  
Glucose Tolerance Tests ◽  
Bilateral Carotid Artery

Vascular contributions to cognitive impairment and dementia (VCID) is a spectrum of cognitive deficits caused by cerebrovascular disease, for which insulin resistance is a major risk factor. A major cause of VCID is chronic cerebral hypoperfusion (CCH). Under stress, sustained hypothalamic-pituitary-adrenal axis (HPA) activation can result in insulin resistance. Little is known about the effects of CCH on the HPA axis. We hypothesized that CCH causes sustained HPA activation and insulin resistance. Male rats were subjected to bilateral carotid artery stenosis (BCAS) for 12 weeks to induce CCH and VCID. BCAS reduced cerebral blood flow and caused memory impairment. Plasma adrenocorticotropic hormone was increased in the BCAS rats (117.2 ± 9.6 vs. 88.29 ± 9.1 pg/mL, BCAS vs. sham, p = 0.0236), as was corticosterone (220 ± 21 vs. 146 ± 18 ng/g feces, BCAS vs. sham, p = 0.0083). BCAS rats were hypoglycemic (68.1 ± 6.1 vs. 76.5± 5.9 mg/dL, BCAS vs. sham, p = 0.0072), with increased fasting insulin (481.6 ± 242.6 vs. 97.94± 40.02 pmol/L, BCAS vs. sham, p = 0.0003) indicating BCAS rats were insulin resistant (HOMA-IR:11.71 ± 6.47 vs. 2.62 ± 0.93; BCAS vs. control, p = 0.0008). Glucose tolerance tests revealed that BCAS rats had lower blood glucose AUCs than controls (250 ± 12 vs. 326 ± 20 mg/dL/h, BCAS vs. sham, p = 0.0075). These studies indicate that CCH causes sustained activation of the HPA and results in insulin resistance, a condition that is expected to worsen VCID.

Long-Term Outcomes of Staged Basilic Vein Transposition for Hemodialysis Access in Children

2017 ◽  
Vol 18 (5) ◽  
pp. 366-370 ◽  
Author(s):  
Elias Kfoury ◽  
Christopher J. Demaree ◽  
Mun J. Poi ◽  
Jesus M. Matos ◽  
Carlos F. Bechara ◽  
...  
Keyword(s):  
Tertiary Care ◽  
Primary Patency ◽  
Secondary Patency ◽  
Hemodialysis Access ◽  
Basilic Vein ◽  
Long Term Outcomes ◽  
Av Fistula ◽  
Functional Maturation

Introduction Children requiring long-term hemodialysis often face significant challenges due to their young age and small-vessel caliber for arteriovenous (AV) access creation. In this study, we report our experience of staged basilic vein transposition (BVT) in pediatric patients. Methods All patients undergoing staged BVT at a tertiary care pediatric hospital from 2003 to 2015 were reviewed. Indications for staged BVT included inadequate cephalic conduit or failed AV fistula using cephalic vein. Pertinent clinical variables were analyzed to determine treatment outcomes. Results Forty-two children (24 males, 57%) underwent 46 staged BVT during the study period. Median age was 12.8 ± 4.8 years (range 3-18). The mean weight was 47 ± 5.1 kg (range, 13-126 kg), with four children (10%) weighing ≤20 kg. Mean operative times for initial brachiobasilic AV fistula and staged BVT were 39 ± 12 minutes and 66 ± 17 minutes, respectively. Mean follow-up period was 5.4 ± 1.8 years. Functional maturation was achieved in 93% of BVTs. Early fistula thrombosis within 30 days following BVT occurred in four patients (10%). Late BVT thrombosis occurred in 13 patients (31%). Primary patency rates at 2 years and 4 years were 78% and 72%, respectively. Secondary patency rates at 2 years and 4 years were 86% and 82%, respectively. Conclusions Staged BVT is a durable and reliable autologous hemodialysis access in children who do not have adequate cephalic venous conduit.

scholarly journals Inhibition of the Interaction of AGE–RAGE Prevents Hyperglycemia-Induced Fibrosis of the Peritoneal Membrane

2003 ◽  
Vol 14 (8) ◽  
pp. 2109-2118
Author(s):  
An S. De Vriese ◽  
Allan Flyvbjerg ◽  
Siska Mortier ◽  
Ronald G. Tilton ◽  
Norbert H. Lameire
Keyword(s):  
Diabetic Rats ◽  
Vascular Density ◽  
Peritoneal Membrane ◽  
Glycation End Products ◽  
Pathophysiological Role ◽  
Oxide Synthase ◽  
And Control ◽  
Endothelial Nitric Oxide ◽  
E Mail

ABSTRACT. The peritoneal membrane of long-term peritoneal dialysis patients is characterized by a loss of ultrafiltration capacity, associated morphologically with submesothelial fibrosis and neoangiogenesis. Exposure to high glucose concentrations in peritoneal dialysate and the resultant advanced glycation end-products (AGE) accumulation have been implicated in the development of these changes, but their exact pathophysiological role is unknown. We examined the effect of the interaction of AGE with one of their receptors (i.e., RAGE) on the function and structure of the peritoneum exposed to high ambient glucose concentrations. Streptozotocin-induced diabetic rats and control rats were treated during 6 wk with either neutralizing monoclonal anti-RAGE antibodies or control antibodies. The expression of RAGE was strongly enhanced in the peritoneal membrane of the diabetic animals. The diabetic peritonea were characterized by an elevated transport of small solutes, lower ultrafiltration rates, a higher vascular density, and an upregulation of endothelial nitric oxide synthase expression. These parameters were unaffected by treatment with anti-RAGE antibodies. In contrast, anti-RAGE but not control antibodies prevented upregulation of TGF-β, development of submesothelial fibrosis, and fibronectin accumulation in the peritoneum of diabetic animals. In conclusion, binding of AGE to RAGE increases the expression of TGF-β and contributes to the development of submesothelial fibrosis. Neoangiogenesis and the resultant loss of ultrafiltration capacity are mediated by different pathogenetic pathways. E-mail: [email protected]

Erection Capability Is Potentiated by Long-Term Sildenafil Treatment: Role of Blood Flow-Induced Endothelial Nitric-Oxide Synthase Phosphorylation

2005 ◽  
Vol 68 (1) ◽  
pp. 226-232 ◽  
Author(s):  
Biljana Musicki ◽  
Hunter C. Champion ◽  
Robyn E. Becker ◽  
Tongyun Liu ◽  
Melissa F. Kramer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide
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