Liposomal Nanocarriers Designed for Sub-Endothelial Matrix Targeting under Vascular Flow Conditions.

Vascular interventions result in the disruption of the tunica intima and the exposure of sub-endothelial matrix proteins. Nanoparticles designed to bind to these exposed matrices could provide targeted drug delivery systems aimed at inhibiting dysfunctional vascular remodeling and improving intervention outcomes. Here, we present the progress in the development of targeted liposomal nanocarriers designed for preferential collagen IV binding under simulated static vascular flow conditions. PEGylated liposomes (PLPs), previously established as effective delivery systems in vascular cells types, served as non-targeting controls. Collagen-targeting liposomes (CT-PLPs) were formed by conjugating established collagen-binding peptides to modified lipid heads via click chemistry (CTL), and inserting them at varying mol% either at the time of PLP assembly or via micellar transfer. All groups included fluorescently labeled lipid species for imaging and quantification. Liposomes were exposed to collagen IV matrices statically or via hemodynamic flow, and binding was measured via fluorometric analyses. CT-PLPs formed with 5 mol% CTL at the time of assembly demonstrated the highest binding affinity to collagen IV under static conditions, while maintaining a nanoparticle characterization profile of ~50 nm size and a homogeneity polydispersity index (PDI) of ~0.2 favorable for clinical translation. When liposomes were exposed to collagen matrices within a pressurized flow system, empirically defined CT-PLPs demonstrated significant binding at shear stresses mimetic of physiological through pathological conditions in both the venous and arterial architectures. Furthermore, when human saphenous vein explants were perfused with liposomes within a closed bioreactor system, CT-PLPs demonstrated significant ex vivo binding to diseased vascular tissue. Ongoing studies aim to further develop CT-PLPs for controlled targeting in a rodent model of vascular injury. The CT-PLP nanocarriers established here show promise as the framework for a spatially controlled delivery platform for future application in targeted vascular therapeutics.

The Efficacy of Systemic Doxycycline Administration as an Inhibitor of Intimal Hyperplasia after Balloon Angioplasty Arterial Injury.

BACKGROUND: Intimal hyperplasia (IH) is the most common indicator for secondary intervention in peripheral vascular disease. Matrix metalloproteinases (MMPs) play a role in IH development due to their degradation of the extracellular matrix. Doxycycline (Doxy), a member of the tetracycline family of antibiotics, is a potent MMP inhibitor. We have previously shown that Doxy inhibits MMP activity and vascular smooth muscle cell migration in vitro. We hypothesized that Doxy would decrease MMP activity in vivo and inhibit the development of IH in a rodent model of vascular injury. METHODS AND RESULTS: Doxy (400 mg/pellet) was delivered by a slow-release pellet implanted 3 days prior to or at the time of balloon angioplasty (BA) of the common carotid artery in female rats. At 14 days post-BA, intima-to-media (I:M) ratios were 0.77 ± 0.21 and 1.04 ± 0.32 in the Doxy treated groups, respectively, compared to 1.25 ± 0.26 in the control group (P = not significant; n = 3). Additionally, the tested dose of Doxy in either group had no inhibitory effect on membrane type 1-MMP or MMP-2 tissue levels, as measured by immunohistochemistry, or on systemic levels of MMP, as measured by total MMP serum levels using enzyme-linked immunosorbent assay. At 14 days post-BA, VSMC proliferation in the injured artery was increased to Doxy treatment prior to and at the time of surgery (23.5 ± 3.4 and 27.2 ± 3.9%, respectively), compared to control (11.4 ± 0.4%; n = 3), as measured by proliferating cellular nuclear antigen immunostaining. CONCLUSIONS: In our in vivo model of vascular injury, systemic Doxy administration prior to or at the time of vascular injury does not significantly hinder the progression of IH development. Additional doses and routes of administration could be examined in order to correlate therapeutic serum levels of Doxy with effective MMP inhibition in serum and arterial tissue. However, alternative drug delivery systems are needed in order to optimize therapeutic administration of targeted MMP inhibitors for the prevention of IH development.

Diabetic Foot Ulcers: The Importance of Patient Comorbidity Recognition and Total Contact Casting in Successful Wound Care.

Diabetic foot ulcers (DFUs) are a major burden on the health-care system. The purpose of this study is to investigate factors affecting the healing rate of DFU in a university wound care center. Records of DFU patients treated between July 2013 and February 2015 were reviewed. Demographics, comorbidities, wound characteristics, and treatment modalities including offloading, hyperbaric oxygen treatment, total contact casting, and bioengineered skin were investigated. All patients underwent weekly debridement regardless of treatment modality. A total of 114 patients ages 18 to 98 comprised the study population. Total contact casting was the only treatment associated with increased healing (P = 0.02). Smoking (P = 0.004) and deep vein thrombosis history (P = 0.001) significantly decreased the likelihood of wound healing. Patients with past vascular event trended toward longer healing times (P = 0.07). Total contact casting in combination with weekly wound debridement showed benefit in DFU wound healing, whereas patients with a history of deep vein thrombosis and smoking were less likely to heal.

Impact of elevated cardiac biomarkers on mortality after vascular surgery procedures.

Concurrent cardiac disease is an important cause of morbidity and mortality in vascular surgical patients. Increasingly, cardiac biomarkers are used to identify cardiac injury in these high-risk patients. This review provides data demonstrating that perioperative troponin elevation correlates with poor short- and long-term outcomes for vascular surgical patients. In addition, the data demonstrate that patients with high circulating troponin levels fair worse than those with lower levels. Early identification of patients with cardiac injury using biomarkers allows timely diagnosis, risk stratification, and aggressive medical therapy for vascular surgical patients.

Androgens regulate MMPs and the cellular processes of intimal hyperplasia.

BACKGROUND: Testosterone deficiency has been associated with an increased risk of vascular disease. Matrix metalloproteinases (MMPs) have been implicated in vascular remodeling. Our group has demonstrated an association between female hormones and MMP-modulated intimal hyperplasia. In the present study, we investigated testosterone in the modulation of MMPs and the cellular processes of intimal hyperplasia. MATERIALS AND METHODS: Male vascular smooth muscle cells (VSMCs) were treated with a range of testosterone or dihydrotestosterone (DHT) concentrations (0.3-3000 nM). MMPs were assayed using quantitative polymerase chain reaction, Western blot analysis, and zymography. VSMC migration and proliferation were assayed using Boyden chamber and MTT assays. RESULTS: MT1-MMP gene expression was not affected by low DHT exposure but was downregulated at high levels (3000 nM = 85% ± 3%). TIMP-2 gene expression was downregulated at low DHT exposure (0.3 nM = 82% ± 4%, 3.0 nM = 82% ± 1%) but was not affected at high levels. MMP-2 enzymatic activity was increased at low DHT exposure (3.0 nM = 110% ± 4%) and decreased below basal levels at high doses (300 nM = 91% ± 7%, 3000 nM = 77% ± 8%). High concentrations of DHT decreased VSMC migration (3.0 nM = 72% ± 9%, 30 nM = 50% ± 6%, 300 nM = 47% ± 5%, 3000 nM = 53% ± 6%). Testosterone also decreased migration but had less effect. The highest tested concentration of DHT and testosterone decreased the basal VSMC proliferation (3000 nM = 87% ± 3% and 87% ± 4% respectively). CONCLUSIONS: The DHT levels differentially affected the expression of regulatory isoforms responsible for the activation and inhibition of MMP-2, leading to an inverse relationship among the DHT levels, MMP-2 activity, and VSMC migration. In vivo studies will be used to examine testosterone deficiency and supplementation in MMP-modulated intimal hyperplasia in animal models of vascular disease. These studies are needed as a prerequisite to determining whether testosterone replacement in testosterone-deficient men should be evaluated for attenuation of atherosclerosis.

Evaluation of the redesigned conformable GORE TAG thoracic endoprosthesis for traumatic aortic transection.

OBJECTIVE: To evaluate the safety and effectiveness of the conformable GORE TAG thoracic endoprosthesis (CTAG) device (W. L. Gore and Associates, Flagstaff, Ariz) for the endovascular repair of traumatic aortic transections. METHODS: A prospective, nonrandomized, multicenter trial was conducted at 21 sites. Primary safety end points included 30-day all-cause mortality. The effectiveness end point was freedom from a major device event requiring reintervention through 1-month follow-up. RESULTS: Fifty-one subjects were enrolled between December 2009 and January 2011 with polytraumatic injuries and a mean Injury Severity Score of 32 ± 14. The proximal mean intimal aortic diameter measured 24 mm, while the mean distal intimal diameter was 22 mm. A total of 57 CTAG devices were implanted (mean, 1.1/subject; range, 1-2) with a mean patient age of 44 years (range, 21-87) and a male-to-female ratio of 2:1. Technical success was 100% with an operative mortality of 0%. Femoral access was utilized in 96% of patients. The mean procedure time and blood loss was 105 minutes and 148 mL, respectively. All subjects required admission to an intensive care unit with a mean hospital stay of 14.6 days. Adjuvant techniques (ie, lumbar drains and induced hypertension) to prevent paraplegia were used in only 7.8% of patients. No patient developed paraplegia despite 63% having complete or partial left subclavian artery coverage and only 9% of those receiving left subclavian artery revascularization. In addition, there were no device compressions or major device events reported. Overall mortality at 30 days was 7.8%, and all were adjudicated by the clinical events committee as not being device or procedure related. Serious adverse events occurred in 39.2% of patients through 30 days. To date, there have been no conversions to open repair. Two site-reported endoleaks were detected during the mean follow-up of 4.2 months, which did not require reintervention. CONCLUSIONS: The CTAG device was demonstrated to be a safe and effective treatment for traumatic aortic transection based on 30-day outcomes. There were no device-related serious adverse events.

Contemporary outcomes of vertebral artery injury.

OBJECTIVE: Vertebral artery injury (VAI) associated with cervical trauma is being increasingly recognized with more aggressive screening. Disparate results from previous literature have led to uncertainty of the significance, natural history, and optimal therapy for VAI. METHODS: To understand the natural history and treatment outcomes from our experience, we performed a retrospective, single-center review from a level I trauma center for the previous 10 years of all VAI. Injuries were identified from search of an administrative trauma database, a resident-run working database, and all radiology dictations for the same period. All VAI were classified according to segmental involvement, Denver grading scale, and laterality. Analysis of associated injuries, demographics, neurologic outcome, mortality, length of stay, treatment plan, and follow-up imaging was also performed. RESULTS: Fifty-one patients with VAI were identified from 2001 to 2011 from a total of 36,942 trauma admissions (0.13% incidence). Associated injuries were significant with an average New Injury Severity Score of 29.6. Penetrating trauma occurred in 14%. Cervical spine fracture was present in 88% with VAI. Diagnosis was obtained with computed tomographic angiography (CTA) in 95%. Screening was prompted by injury pattern or high-risk mechanism in all cases. Injuries classified according to the Denver grading scale were grade I = 24%, grade II = 35%, grade III = 4%, grade IV = 35%, and grade V = 2%. Distribution across segments included V1 = 18%, V2 = 67%, V3 = 31%, and V4 = 6%. Only one posterior circulation stroke was attributable to VAI. Overall mortality was 8%, with each mortality being associated with significant other organ injuries. Treatment rendered for VAI was antiplatelet therapy (50%), observation (31%), warfarin (17%), and stent (2%). There were no significant differences between treatment groups on any variable with the exception of body mass index (P = .047). Follow-up was obtained for 13% (n = 6) of survivors. The CTA demonstrated injury stability in four patients and resolution in two patients. Accuracy of the administrative trauma database was 53% compared with 96% for the resident-run working database. CONCLUSIONS: Neurologic sequelae attributable to VAI were rare. Grade of VAI or vertebral artery segment did not correlate with morbidity. We did not observe any differences in short-term outcomes between systemic anticoagulation and antiplatelet therapy. Of those patients seen at follow-up, injury resolution or stability was documented by CTA. A conservative approach with either observation or antithrombotic therapy is suggested. If the natural history of VAI includes a very low stroke rate, then therapies with a lower therapeutic index, such as systemic anticoagulation, in the severely injured trauma patient are not supported. Our search strategy urges awareness of the limitations of administrative databases for retrospective vascular study.

Effect of hormone replacement therapy in matrix metalloproteinase expression and intimal hyperplasia development after vascular injury.

BACKGROUND: Postmenopausal women taking hormone replacement therapy (HRT) require secondary intervention after vascular reconstruction more frequently than women not taking HRT, often due to increased development of intimal hyperplasia (IH). Matrix metalloproteinases (MMPs) play a role in IH by degradation and remodeling of components of the vascular basement membrane. The MMP pathway is regulated by a balance between MMPs, membrane-type MMPs (MT-MMPs), and tissue inhibitor of MMPs (TIMPs). We have recently provided evidence for unbalanced regulation of the MT1-MMP/MMP-2 pathway in vascular smooth muscle cells (VSMCs) exposed to hormones in vitro. Herein we study the role of HRT in the development of IH in a postmenopausal rodent model of vascular injury and in the modulation of this MMP regulatory pathway in vivo. METHODS: Female rats were aged to 12 months. Animals were ovariectomized (OVX) and 4 weeks later hormones or placebo was delivered via a 90-day slow-release pellet. After 6 weeks of HRT each rat underwent balloon angioplasty of the left common carotid artery. At 14 days postinjury tissue samples were collected and stained with trichrome elastin and for isoform-specific MMPs. RESULTS: After vascular injury, the intima:media (I:M) ratio was decreased in OVX rats receiving placebos as compared with non-OVX controls (P < 0.05). In OVX animals receiving HRT, estrogen with and without progesterone and progesterone alone slightly increased I:M ratio compared with placebo, although no significant difference was found in any HRT group. Injury-induced intimal expression of MMP-2 and -9 was decreased in OVX placebo animals compared with non-OVX controls (P < 0.05). MMP-2 and -9 levels were subsequently increased by each type of hormone therapy compared with placebo, with a significant increase in MMP-9 in response to estrogen with and without progesterone (P < 0.05). Conversely, TIMP-2 was decreased by estrogen compared with placebo (P < 0.05). There was no effect on intimal MT1-MMP in any group. CONCLUSIONS: In this study we detected a statistically significant decrease in IH as a result of OVX. Subsequent HRT exposure resulted in increased I:M ratios compared with OVX animals given placebo, although significance was not reached with the doses given. Long-term exogenous exposure may have a more deleterious effect compared with acute exposure and should be examined further. We also demonstrated a significant reduction in MMP-2 and -9 and TIMP-2 in response to OVX. Subsequent hormone exposure resulted in the upregulation of MMP-2 and -9 without a counterregulatory increase in TIMP, indicating that HRT modulates the MMP regulatory pathway in vivo. The data suggest that the lack of hormones after OVX protects against pathologic remodeling in our aged model of disease and that exposure to both natural and exogenous hormones could be a negative risk factor resulting in an exaggerated vascular response to injury. Future studies should focus on in vivo manipulation of unbalanced MMP regulation for prevention of IH in response to HRT and in general. Furthermore, the age-associated difference in response to the presence of natural hormones in young vs aged models should be investigated.

Maximal venous outflow velocity: an index for iliac vein obstruction.

Leg swelling is a common cause for vascular surgical evaluation, and iliocaval obstruction due to May-Thurner syndrome (MTS) can be difficult to diagnose. Physical examination and planar radiographic imaging give anatomic information but may miss the fundamental pathophysiology of MTS. Similarly, duplex ultrasonographic examination of the legs gives little information about central impedance of venous return above the inguinal ligament. We have modified the technique of duplex ultrasonography to evaluate the flow characteristics of the leg after tourniquet-induced venous engorgement, with the objective of revealing iliocaval obstruction characteristic of MTS. Twelve patients with signs and symptoms of MTS were compared with healthy control subjects for duplex-derived maximal venous outflow velocity (MVOV) after tourniquet-induced venous engorgement of the leg. The data for healthy control subjects were obtained from a previous study of asymptomatic volunteers using the same MVOV maneuvers. The tourniquet-induced venous engorgement mimics that caused during vigorous exercise. A right-to-left ratio of MVOV was generated for patient comparisons. Patients with clinical evidence of MTS had a mean right-to-left MVOV ratio of 2.0, asymptomatic control subjects had a mean ratio of 1.3, and MTS patients who had undergone endovascular treatment had a poststent mean ratio of 1.2 (P = 0.011). Interestingly, computed tomography and magnetic resonance imaging results, when available, were interpreted as positive in only 53% of the patients with MTS according to both our MVOV criteria and confirmatory venography. After intervention, the right-to-left MVOV ratio in the MTS patients was found to be reduced similar to asymptomatic control subjects, indicating a relief of central venous obstruction by stenting the compressive MTS anatomy. Duplex-derived MVOV measurements are helpful for detection of iliocaval venous obstruction, such as MTS. Right-to-left MVOV ratios and postengorgement spectral analysis are helpful adjuncts to duplex imaging for leg swelling. The MVOV maneuvers are well tolerated by patients and yields physiological data regarding central venous obstruction that computed tomography and magnetic resonance imaging fail to detect.

Smooth muscle cell polymeric transfection is an efficient alternative to traditional methods of experimental gene therapy.

BACKGROUND: Gene therapy shows promise in the treatment of vascular disease. However, traditional transfection methods commonly used in the laboratory are poorly translatable to in vivo conditions, primarily due to the immune response to viral vectors, the cellular toxicity of chemical transfection, and the technical impracticality of electroporation. Biodegradable polymers have shown promise as a safe, predictable, and nontoxic alternative, relying on endocytosis of synthetic polymeric carriers, which are bioconjugated to the targeted genetic material of choice. However, to date most of the feasibility studies have been exclusively performed in stem cells. Differentiated cell types would be prime targets for therapeutic gene modulation in the prevention of various disease processes. We aim to establish polymeric transfection as a method for gene therapy in cells of vascular origin. Here we compared the efficiency of polymeric transfection with chemical transfection agents routinely used in a laboratory setting in vascular smooth muscle cells. METHODS: Human aortic smooth muscle cells (HASMC) were transfected with fluorescently labeled GAPDH siRNA or negative control (NC) siRNA. Transfection methods included poly(B-amino ester) polymer (StemFECT) bioconjugates, DharmaFECT2 complexes, and Santa Cruz complexes. Conjugate endocytosis was confirmed by fluorescent microscopy, and GAPDH gene silencing was assayed by qPCR normalized to 18S. RESULTS: Santa Cruz reagent complexes were the least efficient, with the maximum achievable gene silencing using a 9 µL reagent : 70 pmol siRNA/mL complex (59% ± 6%; n = 3). Maximum GADPH gene silencing using DharmaFECT2 was achieved with a 1.5 µL reagent : 100 pmol siRNA/mL complex (19% ± 1% expression versus NC; n = 4). Equivalent silencing was achieved using a comparable StemFECT bioconjugate of 1.3 µL polymer : 100 pmol siRNA/mL (25% ± 3% expression versus NC; n = 4; P = NS versus DharmaFECT2). By increasing the StemFECT bioconjugate to 1.95 µL polymer : 100 pmol siRNA/mL, gene silencing was significantly increased (10% ± 1% expression versus NC; n = 6; P < 0.05 versus DharmaFECT2 and StemFECT 1.3:100). CONCLUSION: HASMCs were efficiently transfected using polymeric bioconjugates in a manner comparable to and exceeding other transfection agents routinely used in vitro. This proof of concept establishes polymeric transfection as a viable method for in vitro investigation of differentiated vascular cells. Future studies will expand on this method of gene therapy for ex vivo transfection of whole vessel segments and in vivo transfection in animal models of vascular disease. Our long-term goal is to deliver molecular inhibitors of genes thought to play a role in intimal hyperplasia, restenosis, and vessel graft failure.

Role of MT1-MMP in estrogen-mediated cellular processes of intimal hyperplasia.

BACKGROUND: Hormone replacement therapy increases intimal hyperplasia (IH) following vascular intervention. Matrix metalloproteinases (MMPs) play a role in IH development. We have shown estrogen up-regulates MT1-MMP expression, a transmembrane protein that activates MMP-2, and increases vascular smooth muscle cell (VSMC) collagen invasion via increased MMP-2 activity. Here we hypothesize inhibition of MT1-MMP will prevent hormonally-stimulated increased MMP-2 activation and the downstream cellular processes of IH pathogenesis. METHODS: VSMCs from a postmenopausal donor were transfected with MT1-MMP or negative control siRNAs, treated with estrogen (Est), analyzed by q-PCR, Western blot, zymography, migration, invasion, and proliferation assays. RESULTS: Est treatment of MT1-MMP silenced cells still resulted in increased MT1-MMP expression (C = 41% ± 4%; Est = 52% ± 2%; P < 0.05). Silencing of MT1-MMP decreased basal MMP-2 activity (nonsilenced = 100%; MT1-silenced = 87% ± 3%; P < 0.05) but had no effect on basal invasion or proliferation. Est treatment of MT1-MMP silenced cells still resulted in increased MMP-2 activity (C = 87% ± 3%; Est = 101% ± 4%; P < 0.05) and invasion (C = 89% ± 6%; Est = 109% ± 3%; P < 0.05) compared with MT1-MMP silenced control cells. However, silencing of MT1-MMP did inhibit Est- and serum-stimulated proliferation (C = 106% ± 18%; Est = 104% ± 16%; FBS = 121% ± 24%; P = NS). CONCLUSION: Silencing of MT1-MMP in aged VSMCs results in impaired but not complete inhibition of basal and Est-stimulated increases in MMP-2 activity. Other mechanisms appear to be playing a role in hormonally-regulated cellular processes of IH pathogenesis. Future studies will target other signaling cascades, with the goal of identifying mechanisms responsible for hormonally-modulated unbalanced MMPs. In vivo manipulation of the expression patterns of MT1-MMP will be examined for the prevention of IH in animal models of vascular disease.

Serum levels of matrix metalloproteinase-2 as a marker of intimal hyperplasia.

BACKGROUND: A primary component in the development of intimal hyperplasia (IH) in response to vascular injury is basement membrane remodeling. Matrix metalloproteinases (MMPs) play a major role in this process by degradation of basement membrane proteins, mainly collagen type IV. Vascular injury initiates an inflammatory cascade with the release of tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and C-reactive protein (CRP). We hypothesize serum levels of these elements may serve as biomarkers of the development of IH. METHODS AND RESULTS: At baseline, 2, 7, 10, and 14 days post-balloon angioplasty of the carotid artery, rat tissue samples were stained with Masson trichrome elastin to examine IH. Intima:media ratios (I:M) increased significantly over time postinjury. Serum samples were collected at the time of tissue sampling, and levels of MMP-2, MMP-9, collagen type IV, TNFalpha, IL-1beta, and CRP were assayed using sandwich enzyme-linked immunosorbent assay (ELISA). MMP-2 serum levels at 7, 10, and 14 days postinjury were significantly elevated compared with baseline. Other elements were not significantly elevated. CONCLUSION: Early and persistent elevation in the serum levels of MMP-2 may be a useful biomarker of basement membrane remodeling and the presence of IH.

Development and validation of the Rapid Estimate of Adult Literacy in Vascular Surgery (REAL_VS).

The purposes of this study were to develop and validate the (1) Rapid Estimate of Adult Literacy in Vascular Surgery (REAL_VS) for researchers studying the impact of literacy skills as related to vascular surgery-related knowledge and outcomes and (2) short version of the REAL_VS (REAL_VSs) to allow clinicians to gauge their patients' familiarity with vascular surgery-related terms. A three-phase process was used to identify potential words for inclusion in the REAL_VS, including reviewing Internet-based patient education material content and listening to a random sample of 50 archived audiorecordings of vascular surgeon-patient encounters. The REAL_VS was composed of 75 terms (e.g., stent, gangrene, invasive, aneurysm) of varying pronunciation difficulty. One hundred fifty-two English-speaking patients (>or=18 years of age) attending a university-based vascular surgery clinic were recruited to participate in this study (mean age = 61.4 +/- 14.6 years). During face-to-face interviews, patients' sociodemographic information was collected, and patients were administered the widely used Rapid Estimate of Adult Literacy in Medicine (REALM) and REAL_VS. Mean scores on the REALM (56.9 +/- 14.0) and REAL_VS (63.3 +/- 15.6) were highly correlated (Spearmans rank correlation [rho] = 0.91; p < 0.00). Internal consistency of the REAL_VS (Cronbachs alpha = 0.98) was excellent. Mean scores on the REAL_VSs (4.1 +/- 2.7) were highly correlated with both the REALM (rho = 0.82; p < 0.00) and REAL_VS (rho = 0.94; p < 0.00). Internal consistency, measured using Cronbachs alpha, of the REAL_VSs was 0.86. This study demonstrates that both the REAL_VS and REAL_VSs are both promising tools for use in vascular surgery research and clinical practice, respectively.

Regulation of vascular smooth muscle cell expression and function of matrix metalloproteinases is mediated by estrogen and progesterone exposure.

OBJECTIVE: Postmenopausal women receiving hormone replacement therapy (HRT) have been reported to have more adverse outcomes after vascular reconstructions, including increased intimal hyperplasia development and bypass graft failure. HRT may be affecting the pathway contributing to intimal hyperplasia. An important component of this pathway involves matrix metalloproteinases (MMPs), implicated in vascular remodeling due to their ability to degrade components of the extracellular matrix. We hypothesize that estrogen (Est) and progesterone (Prog) upregulate the MMP pathway in vascular smooth muscle cells (VSMCs) thereby increasing MMP activity and function. METHODS AND RESULTS: VSMCs were incubated with Est (5 ng/mL), Prog (50 ng/mL), Est + Prog combination (Est/Prog), and/or doxycycline (40 microg/mL; Doxy). Using reverse transcriptase polymerase chain reaction (RT-PCR) analysis we have previously shown membrane type 1-MMP (MT1-MMP) messenger ribonucleic acid (mRNA) levels are significantly increased by Est. Here, Western blot analyses indicated MT1-MMP and MMP-2 protein levels, not tissue inhibitor of MMP-2 (TIMP-2), were increased in response to Est and Est/Prog (P < .05 vs control). In-gel zymography revealed that Est and Est/Prog resulted in increased MMP-2 activity (hormone groups, P < .05 vs control) with no significant difference among the hormone groups. VSMC migration was increased by 45 +/- 14% in response to Est (P < .05 vs control), as measured using a modified Boyden chamber assay. Doxycycline significantly inhibited basal and Est/Prog-stimulated increases in MMP-2 activity (P < .05 vs control; P < .05 vs hormone groups), and partially blocked basal and hormonally stimulated migration (P < .05 vs control and Est). CONCLUSION: Estrogen and progesterone affects the MMP pathway by increasing MMP-2 enzymatic activity, possibly via the upregulation of MT1-MMP expression without a corresponding increase in TIMP expression. This increased collagenase activity increases VSMC motility and their ability to migrate through a collagen type IV lattice. Est/Prog upregulation of MT1-MMP may contribute to the adverse effect of HRT on vascular interventions.

Effect of hormones on matrix metalloproteinases gene regulation in human aortic smooth muscle cells.

BACKGROUND: Postmenopausal women receiving hormone replacement therapy have more adverse outcomes after vascular reconstructions. Estrogen-binding receptors have been identified on vascular smooth muscle cells (VSMCs), indicating that vascular function may be under direct hormonal control. A key group of enzymes involved in vascular remodeling are matrix metalloproteinases (MMPs). Here we studied the effect of estrogen (Est) and progesterone (Prog) on MMP gene expression in human VSMCs. METHODS AND RESULTS: VSMCs were incubated with Est (5 ng/mL), Prog (50 ng/mL), Est+Prog combination (Est/Prog), and interleukin-1beta (100 U/mL; IL-1beta). Gene array analysis indicated Est+IL-1beta increased the expression of MMP-3. Reverse transcriptase-polymer chain reaction (RT-PCR) analyses revealed MMP-3 mRNA levels were significantly increased by Est/Prog+IL-1beta treatment. However, Western blot and further RT-PCR analyses indicated no change in MMP-3 in response to hormones alone. RT-PCR analyses revealed membrane type 1 (MT1)-MMP mRNA levels, not MMP-2 or tissue inhibitor of MMP (TIMP), were significantly increased by Est/Prog+IL-1beta, and Western blot analyses confirmed a significant increase in MT1-MMP protein in response to Est alone. CONCLUSION: Estrogen and progesterone affect the MMP pathway of VSMCs via isoform specific mechanisms and may lead to unbalanced MMP regulation. Estrogen up-regulates MT1-MMP without a corresponding increase in TIMP-2, known activator and inhibitor of MMP-2, respectively. Additionally, estrogen up-regulates MMP-3 only in the presence of IL-1beta. This differential regulation, combined with case-specific variations in degree of inflammatory response, may explain why some women receiving exogenous hormone therapy at the time of vascular interventions are more susceptible to complications.

The excluder aortic endograft.

Since its introduction, more than 59000 patients have been treated with Gore Excluder endoprosthesis (GORE) for abdominal aortic aneurysm (AAA) in the past 11 years. It has become clearer that differences in device delivery and design provide certain advantages that may favor one anatomical milieu over another. Behavior of the aneurysm sac also seems to be graft dependent as more long-term data become available. The currently available low-permeability GORE seems to have addressed the problem of endotension noted with previous designs. Cumulative data are reviewed, and the data demonstrate very low perioperative morbidity and mortality and excellent protection from aneurysm-related complications with the GORE device. Superior ease of use, excellent trackability, and rare failures requiring acute open conversion characterize the GORE device. By addressing clinical demands of aortic endografting, Gore has eclipsed other endografts in the industry to now dominate the US market. The aim of this review is to describe the history, experience, advantages, and future goals with the GORE for the treatment of AAA.

Endovascular repair of cervical aortic arch aneurysm.

Cervical aortic arch (CAA) is a rare congenital anomaly of the aortic arch. Rarely, CAA is associated with aneurysm of the arch and great vessels. A 32-year-old male patient, previously in good health, presented with 2 weeks of severe chest pain. Radiographic evaluation revealed a CAA with aneurysmal dilation of the distal aortic arch. The aneurysm extended into the left subclavian artery. There was also marked angulation just distal to the aneurysmal portion. The aneurysmal arch and subclavian artery were repaired using a thoracic aortic endograft. An open axillary-to-axillary bypass was performed, and the left axillary artery was ligated proximally. This restored perfusion to the left upper extremity and effectively excluded the aneurysm sac. Immediately postoperatively, the patient's chest pain resolved, and he has remained symptom free. To the authors' knowledge, this is the first reported repair of a cervical arch aneurysm by endovascular technique.

Can screening items identify surgery patients at risk of limited health literacy?

BACKGROUND: Health literacy skills (HLS) have been shown to have a major impact on patient outcomes. To identify patients with limited or marginal HLS, the accuracy of three established screening items were examined. MATERIALS AND METHODS: We studied English-speaking adults (>or=21 years) attending a university-based vascular surgery clinic. Structured interviews were conducted to assess sociodemographic characteristics, screening items, and HLS. Area under the receiver operating characteristic (AUROC) curves were plotted to assess the discriminatory capacity of each screening item in detecting patients with limited/marginal HLS. RESULTS: One hundred patients agreed to enter the study and met inclusion criteria. The mean age was 62.0 +/- 12.9; 65 were female; 96 were Caucasian; and 32 had not completed high school. The three screening items were effective in detecting patients with limited (n=18) or marginal (n=21) HLS. "How often do you have someone (like a family member, friend, or hospital worker) help you read hospital materials?" (AUROC of 0.83; 95% confidence interval [CI]=0.73, 0.92), "How often do you have problems learning about your medical condition because of difficulty understanding written information?" (AUROC of 0.77; 95% CI=0.67, 0.86), and "How confident are you filling out medical forms by yourself?" (AUROC of 0.76; 95% CI=0.66, 0.86) were effective in detecting those with limited/marginal HLS skills. CONCLUSIONS: Our findings provide further evidence of the clinical usefulness of these screening items for detecting inadequate HLS in this patient population. Surgeons should consider administering these easy screening items to identify patients at greatest risk of limited or marginal HLS.