Background: Doxycycline has been shown to prevent arterial calcification via attenuation of matrix metalloproteinases (MMP) in preclinical models. We assessed the effects of doxycycline on progression of arterial calcification in patients enrolled in the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA 3 CT). Methods: Two hundred and sixty-one patients were randomized to 100 mg doxycycline twice daily or placebo. Arterial calcification was measured in abdominal vessels on noncontrast computed tomography scans. Patients with baseline computed tomography scan and 1 or more follow-up scans within the 2-year study were included for analysis. For individual arteries, mean change in iliofemoral artery calcification over time was calculated via linear regression. Serum MMP-3 and MMP-9 levels were measured at baseline and 6 months. Results: Sixty-five patients in the doxycycline and 66 in the placebo arm were included in this analysis. Baseline characteristics between the groups were similar. The unadjusted mean change in iliofemoral calcium score per year trended toward higher values in patients treated with doxycycline compared with placebo (322 +/- 399 units/year vs. 217 +/- 307 units/year, P 1 / 4 0.09). After 6 months, changes in serum MMP-3 and MMP-9 levels were not significantly different between study arms. Conclusions: In patients with small aortic aneurysm, treatment with doxycycline 100 mg twice daily did not decrease circulating levels of the matrix degrading enzymes MMP-3 and 9 or alter the progression of arterial calcification.

Our study demonstrated that PAI-1 is elevated in mice with STZ-induced diabetes. While hyperglycemic mice show significantly reduced AAA growth compared to normoglycemic AAA controls, no difference in aortic growth is observed between hyperglycemic and normoglycemic PAI-1 KO mice. Regardless of treatment status, PAI-1 deficient mice experience significantly reduced AAA growth compared to C57 control mice. We conclude that while the fibrinolytic pathway and PAI-1 are influential in AAA development, hyperglycemia-induced elevated PAI-1 expression does not play a crucial role in hyperglycemic inhibition of AAA growth. Conversely, PAI-1 deficiency appears to inhibit AAA growth regardless of glycemic status.

The patient was a 41-year-old woman with a history of postpartum class New York Heart Association class II cardiomyopathy. She had undergone biventricular implanTable cardiac defibrillator lead extraction. The procedure was complicated by laceration of the superior vena cava, innominate artery, and confluence of the left subclavian artery. Emergent repair with full cardiopulmonary bypass with bovine pericardial patch angioplasty was performed. During the course of 2 years, the patient had developed superior vena cava syndrome. She described worsening symptoms of severe headaches, blurred vision, near syncope with bending over, and a choking sensation despite sleeping at a 45° head-up angle. Additionally, the patient had developed moderate tricuspid valve regurgitation, which required repair. We elected to repair this patient with a spiral vein graft, in addition to tricuspid valve annuloplasty. Bilateral great saphenous veins were harvested and wrapped around a 36F chest tube such that a 9-mm × 12-cm spiral vein graft was created (Fig 1). After repair of the tricuspid valve, the right internal jugular vein was exposed, and the graft was tunneled through the thoracic inlet and inside a 12-mm ringed polytetrafluoroethylene graft to provide external support. The graft was then anastomosed from the right internal jugular vein to the right atrium. The patient did well and was discharged 6 days postoperatively. During follow-up, the patient has done very well (Fig 2). Five months after surgery, a venogram demonstrated a patent graft, with no pressure gradient across the graft.Fig 2Preoperative (Left) and postoperative (Right) three-dimensional computed tomography reconstructions of the patient demonstrating remarkably decreased venous collaterals. (Bottom) A postoperative venogram demonstrating the widely patent jugular–atrial venous bypass.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Abdominal aortic aneurysm (AAA) is a common progressive disease and a significant cause of morbidity and mortality. Despite being a leading risk factor in most cardiovascular diseases, diabetes mellitus is protective of AAA. Diabetes mellitus has been repeatedly shown to be negatively associated with AAA incidence, diameter, growth, and rupture. The relationship of these growth changes to the proinflammatory effects of diabetes has not been studied.

Development of abdominal aortic aneurysms (AAAs) evolves through stages from normal aortic size to mild ectasia and further dilation to small aneurysm. This study analyzed the proximal aortic neck, which may be susceptible to pharmacologic modification by metalloproteinase inhibition (with doxycycline) at a smaller aortic size. In addition, endovascular aneurysm repair is dependent on stability of this aortic neck for sealing and fixation, which could be compromised by aortic dilation. This study compared neck diameter during 2 years in patients from the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA3CT; NCT01756833) based on the randomized study arm. There were 197 participants from N-TA3CT who were included in this analysis if they completed pre-enrollment and 24-month or later computed tomography imaging; 26 were female with baseline AAA maximal transverse diameter between 3.5 and 4.5 cm, and 171 were male and with baseline small AAA between 3.5 and 5.0 cm. During 2 years, 96 were treated with doxycycline and 101 received matching placebo. Neck diameter measurements were performed in an orthogonal plane in a centralized imaging core laboratory, at the lowest significant renal artery, 5 mm, 10 mm, and 15 mm caudal. Two-tailed parametric t-tests were used to compare differences between treatment groups. Mean infrarenal aortic diameters are demonstrated in the Table. There is no clinically important difference in neck size between patients who received doxycycline and patients who received placebo. Doxycycline cannot be recommended for stabilization of the infrarenal neck.TableMean infrarenal aortic diameter in the full analysis and per-protocol populations. Considering multiple testing at four different levels, there is no statistically significant difference in neck diameter or change in diameter over two years when patients are treated with doxycycline. A per-protocol population was defined on the basis of ≥ 80% capsule count adherence until primary endpointFull analysis populationDoxycyclinePlaceboDifference (95% CI)P valueN = 96N = 101Mean ± SDMean ± SDMean ± SDMTD at LRA (cm), mean (SD) Baseline2.465 (0.444)2.458 (0.292)0.007 (−0.098 to .112).89 2 years2.473 (0.496)2.415 (0.277)0.058 (−0.054 to 0.170).31 Change over 2 years0.008 (0.152)-0.043 (.157)0.05 (0.007 to 0.094).02MTD 5 mm below LRA (cm), mean (SD) Baseline2.486 (0.482)2.464 (0.326)0.022 (−0.093 to 0.137).70 2 years2.501 (0.554)2.463 (0.328)0.038 (−0.089 to 0.165).56 Change over 2 years0.015 (0.157)−0.001 (0.148)0.016 (−0.027 to 0.059).47MTD 10 mm below LRA (cm), mean (SD) Baseline2.546 (0.502)2.502 (0.38)0.044 (−0.081 to .169).49 2 years2.586 (0.608)2.519 (0.402)0.067 (-0.077 to 0.212).36 Change over 2 years0.040 (0.229)0.016 (0.177)0.024 (-0.034 to 0.081)0.42MTD 15 mm below LRA (cm), mean (SD) Baseline2.618 (0.533)2.574 (0.421)0.044 (-0.091 to 0.178).52 2 years2.664 (0.625)2.602 (0.462)0.062 (-0.092 to 0.216).43 Change over 2 years0.046 (0.236)0.028 (0.169)0.018 (-0.039 to 0.076).53Per-protocol populationDoxycyclinePlaceboDifference (95% CI)P valueN = 60N = 68Mean ± SDMean ± SDMean ± SDMTD at LRA (cm), mean (SD) Baseline2.488 (0.504)2.441 (0.277)0.047 (−0.093 to 0.187).51 2 years2.504 (0.549)2.416 (0.268)0.089 (−0.060 to 0.237).24 Change over 2 years0.016 (0.151)−0.026 (0.159)−0.012 (−0.012 to 0.096).12MTD 5 mm below LRA (cm), mean (SD) Baseline2.492 (0.536)2.457 (0.328)0.035 (−0.119 to 0.189).65 2 years2.516 (0.612)2.462 (0.318)0.054 (−0.114 to 0.222).52 Change over 2 years0.024 (0.160)0.004 (0.160)0.019 (−0.037 to 0.075).50MTD 10 mm below LRA (cm), mean (SD) Baseline2.552 (0.546)2.521 (0.396)0.032 (−0.134 to 0.197).71 2 years2.592 (0.644)2.541 (0.398)0.052 (−0.133 to 0.237).58 Change over 2 years0.040 (0.253)0.020 (0.191)0.-20 (−0.058 to 0.098).61MTD 15 mm below LRA (cm), mean (SD) Baseline2.632 (0.555)2.609 (0.445)0.023 (−0.152 to 0.198).80 2 years2.681 (0.654)2.646 (0.471)0.034 (−0.163 to 0.232).73 Change over 2 years0.049 (0.277)0.038 (0.169)0.012 (−0.068 to 0.091).77 Open table in a new tab

Samuels, Jason M. MD; Sun, Kaiwen; Moore, Ernest E. MD, FACS; Cohen, Mitchell J. MD, FACS; Sumislawski, Joshua J. MD; Coleman, Julia R. MD, MHS; Sauaia, Angela MD, PhD; Baxter, Bernard T. MD, FACS; MacTaggart, Jason N. MD, FACS Author Information

This paper presents micro-particle tracking velocimetry measurements over cultured bovine aortic endothelial cell monolayers in microchannels. The objective was to quantify fluid forces and cell morphology at the sub-cellular scale for monolayers subjected to steady shear rates of 5, 10, and 20 dyn/cm2. The ultimate goal of this study was to develop an experimental methodology for in vitro detailed study of physiologically realistic healthy and diseased conditions. Cell topography, shear stress, and pressure distributions were calculated from sets of velocity fields made in planes parallel to the microchannel wall. For each experiment, measurements were made in 3 h intervals for 18 h. It was found that there is a three-dimensional change in cell morphology as a result of applied shear stress. That is, cells flatten and become more wedge shaped in the stream direction while conserving volume by spreading laterally, i.e., in the cross-stream direction. These changes in cell morphology are directly related to local variations in fluid loading, i.e., shear stress and pressure. This paper describes the first flow measurements over a confluent layer of endothelial cells that are spatially resolved at the sub-cellular scale with a simultaneous temporal resolution to quantify the response of cells to fluid loading.

Objective: Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease. Studies of human aneurysm tissue demonstrate dense inflammatory cell infiltrates with CD4(+) T cells predominating. Regulatory T cells (Tregs) play an important role in inhibiting pro-inflammatory T cell proliferation, therefore, limiting collateral tissue destruction. The aim of this study was to investigate whether ex vivo augmentation of human Tregs attenuates aneurysm formation in humanized murine model of AAA. Methods: Circulating Treg population in AAA patients and age- and gender-matched controls were determined by real-time polymerase chain reaction and flow cytometry. To create humanized murine model of AAA, irradiated Ragl-deficient (Rag1(-/-)) mice, without mature T lymphocytes, at 7 weeks of age were given 5 x 10(6) of human CD4(+) T cells intraperitoneally. Then the mice underwent CaCl2 aneurysm induction. Aortic diameters were measured before and at 6 weeks after aneurysm induction. Aortic tissue was collected for histology and protein extraction. Verhoeff-Van Gieson stain was used for staining elastic fiber. CD4(+) T cells in the aortic tissue were detected by immunohistochemical staining. Results: In human peripheral blood mononuclear cells, the proportion of Tregs are decreased in AAA patients compared with matched control patients with significant vascular disease. We first validated the role of Tregs in the CaCl2 model of AAA. To determine the role of human T cells in AAA formation, Rag1(-/-) mice, resistant to CaCl2-aneurysm induction, were transplanted with human CD4(+) T cells. Human CD4(+) T cells were able to drive aneurysm formation in Rag1(-/-) mice. We show that ex vivo augmentation of human Tregs by interleukin-2 resulted in decreased aneurysm progression. Conclusions: These data suggest that the ex vivo expansion of human Tregs may be a potential therapeutic strategy for inhibiting progression of AAA.

Objectives: Abdominal aortic aneurysm (AAA) is a chronic disease characterized by persistent inflammation maintained by an array of inflammatory cells and mediators. Interleukin 1 beta (IL-1β) has largely been considered a pro-inflammatory cytokine but, interestingly, our previous studies of human AAAs showed that activated T-cells from patients with AAAs expressed lower levels of IL-1β compared to matched control patients without AAAs. This led us to hypothesize that IL-1β could have a protective role in preventing the development of AAA. Methods: Abdominal aortic aneurysms were induced in IL-1 receptor KO (IL-1R -/- ) and control mice using the CaCl 2 murine model of AAA. Mice were sacrificed six weeks after aneurysm induction. Aortic diameters were measured and compared at the time of aneurysm induction and sacrifice. Aortic samples were further evaluated histologically using connective tissue staining to assess the aortic structure in both groups. Results: At the time of sacrifice, IL-1R -/- mice demonstrated a 73.9 ± 3.3% increase in aortic diameter compared to a 25.9 ± 5.8% increase in wild type control mice (p<0.05). On histology, IL-1R -/- mice had more severe disruption of the aortic architecture compared to control mice. These data suggest that in the absence of IL-1β signaling, mice are more susceptible to aneurysms and develop more severe pathology. Conclusion: The current mouse data, in combination with our previous human studies, suggest a protective role for IL-1β in abdominal aortic aneurysm. These results are unexpected given that related pro-inflammatory cytokines TNF-α and IFN-γ both promote aneurysm formation.

The origin of the vertebral artery (VA) is a common site of atherosclerosis that may lead to posterior circulation infarcts. Surgery was once the mainstay of therapy for proximal VA disease but contemporary studies suggest interventional approaches are now more common. We present a case series of VA transposition in 5 patients and a systematic review of literature comparing angioplasty/stent with surgical revascularization. A retrospective chart review showed 5 patients (1 in 1992, 4 since 2004) underwent vertebral to common carotid transpositions. A systematic search for all studies that evaluated VA interventions was done through MEDLINE and bibliographic search. Various demographic and endpoint variables were extracted. Our case series comprises 5 patients (mean age: 75.4 years, M:F 4:1, symptomatic 100%). Shunts were used in two cases. We had no wound complications or postoperative morbidity. The mean follow was 23.8 months with no stroke/TIAs and 100% patency on Doppler. One patient died from lung cancer 4 years after surgery and one 6 years after surgery from unknown causes. 30 studies on VA stenting and/or angioplasty were identified (1981-2009). There were 8 studies describing surgery (1984-2000). Following surgical treatment, lower rates of restenosis (2.3%) were seen with longer follow-up, but wound complications were relatively common. Restenosis was a problem after stent placement with no difference between bare metal (27.7%) or drug eluting stents (26.1%). The duration of follow-up and presence of bilateral VA disease was significantly associated with restenosis on regression analysis. Unexpectedly, degree of stenosis was inversely related to degree of initial stenosis. Surgery and endovascular interventions have good initial technical success. Restenosis is problematic with bare metal or drug-eluting stents. Surgery is associated with a higher risk of wound complications but provides superior longterm results.

Objective: The purpose of this study was to determine the accuracy of high‐resolution ultrasound in measuring the diameter of infrarenal abdominal aorta and to compare its use to videomicrometer, which is the most commonly used method in the studies of animal models of abdominal aortic aneurysm (AAA).Methods: Mice (C57BL/6), at 8 weeks age, underwent AAA induction by periaortic application of CaCl2. The diameter of the infrarenal aorta was measured at aneurysm induction and 8 weeks after aneurysm induction with videomicrometer and ultrasound by M‐mode ultrasonography.Results: The mean diameter of the infrarenal abdominal aorta at aneurysm induction was 535 ± 8.3 μm by videomicrometer and 531 ± 7.9 μm by ultrasound. Eight weeks after CaCl2 aneurysm induction, the mean aortic diameter was 892 ± 59.1μm by videomicrometer and 902 ± 55.8 μm by ultrasound. The mean differences of the measured diameters by the two methods were 7.8 μm (SE=12.2 μm) at initial measurement and 10.3 μm (SE=36.9 μm) at 8 weeks after aneurysm induction. The linear correlation coefficient (r value) for the diameter after 8 weeks aneurysm induction was 0.785. Using this criteria, there was a consistent, relative narrowing calculated by both videomicrometer and ultrasound. Conclusion: The mean difference, when taken together with a good linear correlation coefficient of the diameters as measured by videomicrometer and ultrasound, makes this technique acceptable. In addition, ultrasound is suitable for keeping track of the aortic diameter changes during mouse aneurysm development and treatment without open surgery.

Abnormal mitochondrial function is present in patients with peripheral arterial disease and may contribute to its clinical manifestations. However, the specific biochemical mitochondrial defects and their association with increased oxidative stress have not been fully characterized. Gastrocnemius muscle was obtained from peripheral arterial disease patients (n = 25) and age-matched controls (n = 16) and mitochondrial parameters were measured. Complexes I through IV of the electron transport chain were individually evaluated to assess for isolated defects. Muscle was also evaluated for protein and lipid oxidative changes by measuring the levels of protein carbonyls, lipid hydroperoxides, and total 4-hydroxy-2-nonenal binding and for the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. Mitochondrial electron transport chain complexes I, III, and IV in arterial disease patients demonstrated significant reductions in enzymatic activities and mitochondrial respiration compared to controls. Oxidative stress biomarker analysis demonstrated significantly increased levels of protein carbonyls, lipid hydroperoxides, and 4-hydroxy-2-nonenal compared to control muscle. Antioxidant enzyme activities were altered, with a significant decrease in superoxide dismutase activity and significant increases in catalase and glutathione peroxidase. Peripheral arterial disease is associated with abnormal mitochondrial function and evidence of significant oxidative stress.

Background. Matrix metalloproteinase (MMP)-12 levels are increased in the abdominal aortic aneurysm (AAA), implicating this protease in AAA pathogenesis. The Purpose of this study was to assess the role of MMP-12 in aneurysm formation.Methods. A murine aneurysm model was gene-rated by periaortic application of 0.25 mol/L calcium chloride (CaCl2) for 15 minutes. Aortic diameters were measured and compared before and 10 weeks after aneurysm induction. Aortic diameter changes for wild type (WT) and MMP-12 knockout (MMP12(-/-)) mice were determined. MW-12 production in mouse aorta was analyzed by casein zymography. MMP-2 and MMP-9 expressions were examined by gelatin zymography. Immunohistochemical study was used to measure macrophage infiltration into the aorta.Results. There is an increase of 63 +/- 5% (mean +/- SEM) in aortic diameters of WT mice after CaCl2 inductions, while MMP-12(-/-) mice increased only 26 +/- 14%. Connective tissue staining of aortic sections from WT mice showed disruption and fragmentation of medial elastic fibers, while MMP-12(-/-) mice showed only focal elastic lamellae breakdown. MMP-12 levels in WT mice were significantly increased after CaCl2 treatment, whereas no MMP-12 was detected in MMP-12(-/-) mice. There was no difference in the MMP-2 and MMP-9 productions between WT and MMP-12(-/-) mice. Immunnhistochemical analysis demonstrated that infiltrating macrophages in the aorta of MMP-12(-/-) mice were significantly less than WT controls.Conclusions. MMP-12 deficiency attenuates aneurysm growth, possibly by decreasing macrophage recruitment.

Background. Microscopic analysis of abdominal aortic aneurysms (AAAs) demonstrates an abundance of infiltrating leukocytes. The chemokine receptors CCR2 CCK5, and CXCR3 are associated with pathways implicated previously in aneurysm pathogenesis. We hypothesized that genetic deletions of CCR2 CCR5, and CXCR3 would limit. leukocyte infiltration and aneurysm formation in a mouse model of AAA.Methods. CCR2(-/-), CCP,5(-/-), CXCR3(-/-) , and control mice of the same genetic background were subject to periaortic application of calcium chloride. Aortic diameters were measured before aneurysm induction and at harvest 6 weeks later. Diameters were compared using the Mann-Whitney test. Aortas were stained with H&E and trichrome for histologic analysis. Aortic MMP-2 and MMP-9 activities were measured using zymography.Results. Aneurysm formation was attenuated in CCR2(-/-) mice with the final mean aortic diameter less than that of the control mice (P <. 01). Histology revealed preservation of the lamellar architecture and decreased inflammatory cells. Aortic MMP-2 and MMP-9 levels were decreased in CCR2(-/-) mice. CCR5(-/-) and CXCR3(-/-) mice demonstrated no Protection from aneurysm formation, which was corroborated by the tissue histology showing similar inflammatory cell infiltration and elastin degradation.Conclusions. The CCR2 receptor is involved directly in AAA formation, whereas the CCR5 and CXCR3 receptors are not.