Early Results From the Pivotal Trial Substudy of the GORE® EXCLUDER® Conformable Endoprosthesis in Angulated Necks.

OBJECTIVE OR BACKGROUND: To report the investigational device exemption (IDE) study 1-year clinical outcomes of the high neck angulation (HNA) substudy of the GORE® EXCLUDER® Conformable AAA Endoprosthesis (EXCC) for treatment of infrarenal abdominal aortic aneurysms (AAA). METHODS: This study is a prospective, multicenter clinical trial conducted in the United States and included core laboratory assessment of imaging and independent event adjudication. Anatomic criteria for enrollment in the HNA substudy included infrarenal aortic neck angulation >60° and ≤90° with aortic neck length ≥10 mm. Primary safety endpoints included blood loss >1000 mL, death, stroke, myocardial infarction, bowel ischemia, paraplegia, respiratory failure, renal failure, and thromboembolic events. Primary effectiveness endpoints included technical success, absence from Type I and III endoleak, migration (≥10 mm), sac enlargement (≥5 mm), sac rupture, and conversion to open repair. RESULTS: Between January 2018 and February 2022, 95 patients were enrolled in the HNA substudy across 35 sites. Of the 95 patients, 71 (74.7%) were male and the cohort average age was 74.4 years old. The mean infrarenal proximal aortic neck angle was 71.6° and mean AAA size was 62.9 mm. Overall technical success was achieved in 93 (97.9%) patients. Freedom from a primary safety endpoint through 30 days was 96.7%; 3 (3.3%) patients had blood loss >1000 mL. Freedom from the primary effectiveness at 12 months was achieved in 94.8%. Four (4.3%) patients had Type IA endoleak; intervention after the procedure was not required and no subsequent interventions or sac enlargement were noted in these patients. At 12 months, 29 (39.7%) patients experienced a Type II endoleak and 1 (1.3%) patient experienced AAA sac expansion ≥5mm. Through 12 months, 1 (1.3%) patient had a conversion to open surgical repair. There were no aneurysm-related deaths, ruptures, or migration through 12 months. CONCLUSIONS: The IDE study demonstrates safety and effectiveness of the EXCC device in AAA with highly angulated necks (>60° and ≤90°) are preserved at the 12-month follow-up.

Three-Year Outcomes of a US Pivotal Trial Substudy for Conformable Endoprosthesis in >=10 mm Non-Angulated Neck Anatomy.

OBJECTIVE: To report the midterm clinical outcomes from the GORE® EXCLUDER® Conformable AAA Endoprosthesis system (EXCC) pivotal regulatory trial in the United States (U.S.). METHODS: This is a prospective, multicenter, investigational device exemption clinical trial at 31 U.S. sites with Core Laboratory assessment of imaging and independent adjudication of safety. The study enrolled patients with abdominal aortic aneurysms (AAA) with a minimum proximal landing zone ≥ 10mm and proximal neck angulation of ≤ 60 degrees between December 2017 and February 2019 as part of a larger study to gain indications of the EXCC device. Endpoints included patient survival, freedom from secondary interventions, and stent-graft related outcomes. RESULTS: There were 80 patients enrolled (88.8% male, mean 73.5 ± 8.14 years-old). Mean maximum aortic diameter was 57.7±8.0 mm (range, 42.5-82.7). There was 100% freedom from type I and III endoleak and aneurysm-related mortality at 36-months. Freedom from secondary intervention was 91.9 ± (0.83, 0.96, 95% C.I.) at 36-months. There were no device fractures, migrations (>=10 mm), or aneurysm ruptures. At 36 months, thirteen patients (26.5%) had type 2 endoleak, 32 patients (58.2%) had AAA sac regression, 17 (30.9%) had no change in diameter, and 6 (10.9%) had sac enlargement. Seven patients (8.8%) through 36 months underwent reintervention. CONCLUSIONS: The 3-year outcomes have continued to show an adequate safety and efficacy profile of the EXCC device with no aneurysm related mortality or Type I/III endoleak. These results demonstrate durability for an EVAR device in US regulatory trials.

Development and validation of a novel endovascular thrombectomy device to treat deep vein thrombosis: a preclinical study in a swine model.

This study evaluated the safety and efficacy of a novel endovascular thrombectomy device in a swine model of deep vein thrombosis (DVT). The device has an over-the-wire configuration, a manually expandable catching basket, a funnel sheath with a covered stent to minimize the risk of microembolization, and an integrated delivery system. DVT was induced by occluding the right iliac vein with a balloon catheter and injecting thrombin. The novel device was inserted into the inferior vena cava through the right jugular vein access. The device effectively removed the thrombus, restoring venous patency without residual thrombus, vessel injury, or complications. These findings suggest the potential advantages of the novel device over predicate devices. Further clinical evaluation is needed to establish the efficacy of this device in human patients with DVT.

Unpacking the Complexities of a Silent Killer.

An abdominal aortic aneurysm (AAA) is a life-threatening condition that affects millions of people worldwide [...].

Antioxidants and azd0156 Rescue Inflammatory Response in Autophagy-Impaired Macrophages.

Autophagy is a lysosomal degradation system that eliminates and recycles damaged intracellular organelles and proteins. Inflammatory macrophages play a critical role in the development of various age-related inflammatory illnesses such as abdominal aortic aneurysm, atherosclerosis, and rheumatoid arthritis; therefore, identifying the mechanisms that cause macrophage inflammation is crucial for a better understanding of and developing therapeutics for inflammatory diseases. Previous research has linked autophagy to macrophage inflammation; Atg16L1-deficient macrophages increase IL-1 and IL-18 production via inflammasome activation. In this study, however, we show an alternative pathway of macrophage inflammation in an autophagy-deficient environment. We found that inhibiting autophagy in THP1 macrophages progressively increased the expression of p65-mediated inflammatory genes. This effect was reversed by treatment with antioxidants or azd0156, an ataxia telangiectasia mutated (ATM) inhibitor. In addition, our results showed that M1 macrophages inhibit autophagy and induce DNA damage, whereas M2 macrophages activate autophagy and reduce DNA damage. Importantly, the chemical activation of autophagy or ATM inhibition during M1 polarization reduced the M1 phenotype and inflammation, whereas inhibiting autophagy during M2 polarization also reduced the M2 phenotype. Thus, our findings highlight the importance of the autophagy-ATM pathway in driving macrophage inflammation.

Induction of endoplasmic reticulum stress markers in an acromegaly model.

Acromegaly is a growth hormone (GH) excess pathological condition in humans. Acromegaly is associated with somatic disfigurement and a wide range of systemic manifestations such as arthritis, neuropathy, carpal tunnel syndrome, reproductive disorders, metabolic disorders, and gastrointestinal complications. The influence of excess GH on the cellular level could aid in understanding the root causes of acromegaly-related health complications. Previously, we found that GH excess induces DNA damage to somatic cells and reduces the stem cells number and causes premature aging. In this study, an in-depth analysis of the acromegaly RNAseq data revealed the disruption of important biological cellular processes. Gene set enrichment analysis, heatmap, and enrichment analysis of acromegaly RNAseq data revealed induction of endoplasmic reticulum (ER) stress markers in various organs. Interestingly, the induction of ER stress was even more apparent than in aged zebrafish. Splicing of box-binding protein-1 (XBP1) mRNA is a hallmark of ER stress. Therefore, we quantified spliced XBP1 mRNA in different organs of our acromegaly model. Thus, our study emphasizes the importance of ER stress in GH oversecretion, which is important for understanding the health complications of acromegaly.

Effects of Ultrafine Single-Nanometer Oxygen Bubbles on Radiation Sensitivity in a Tumor-Bearing Mouse Model.

Radiation therapy against cancer cells often causes radiation resistance via accumulation of hypoxia-inducible factor 1 subunit alpha (HIF-1α) under hypoxic conditions and severe side effects. Radiation sensitizers without side effects are required to overcome hypoxia-induced radiation resistance and decrease radiation-related side effects in patients with refractory cancer. We previously developed oxygen nanobubble water (NBO2 water) and demonstrated that it suppresses hypoxia-induced radiation resistance in cancer cell lines within the single-nanometer range. This study aimed to elucidate whether NBO2 water could act as a radiosensitizer via regulation of HIF-1α in a tumor-bearing mouse model. Six-week-old female BALB/c mice subcutaneously injected with tumor cells received control water or NBO2 water for 28 days, after which biochemical examinations and radiation treatment were performed. Hypoxic tumor regions were detected immunohistochemically. We found that NBO2 water sensitized radiation reactivity in the xenografted tumors. Notably, NBO2 water administration downregulated the accumulation of HIF-1α in xenografted tumors and did not affect the vital organs of healthy mice. The combination of radiation and single-nanometer NBO2 water without severe side effects may be a promising therapeutic option to improve radiation sensitivity in cancer patients without tolerance to invasive treatments.

Spinal Cord Ischemia Rescue after Hybrid Total Arch Repair with Frozen Elephant Trunk: A Case Report.

Frozen elephant trunk repair is a technique described to simplify total arch repair for Stanford type A aortic dissection. Spinal cord ischemia is a devastating complication after frozen elephant trunk repair. In this report, we describe a case of spinal cord ischemia resulting in paralysis after frozen elephant trunk repair. Our spinal cord ischemia protocol was implemented and rescued patients from paraplegia. We report a dedicated spinal cord ischemia protocol that can rescue patients from paraplegia after hybrid arch repair with frozen elephant trunk.

Cigarette Smoke Extract Activates Tartrate-Resistant Acid Phosphatase-Positive Macrophage.

BACKGROUND: It has been reported that smoking is one of the strongest positive risk factors for abdominal aortic aneurysms (AAAs). Although many studies have been directed to decipher the effect of smoking on AAA, its effect on macrophage activation has not yet been explored. OBJECTIVES: We have reported the importance of osteoclastogenesis (OCG) in aneurysm formation. Therefore, we examined the effect of cigarette smoking on OCG and arterial aneurysmal formation by using cigarette smoke extract (CSE) in this study. METHODS: Macrophage cell lines were stimulated with CSE, and their activation and differentiation were examined in vitro. Since macrophages activated through the OCG pathway are identified by tartrate-resistant acid phosphatase (TRAP) expression, these cells are referred to as TRAP-positive macrophages (TPMs) in this study. We also applied CSE-contained PBS in the calcium chloride-induced mouse carotid aneurysm model in vivo. RESULTS: Macrophages stimulated with CSE expressed significantly higher levels of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), TRAP, cathepsin K, matrix metalloproteinase-9 and membrane-type metalloproteinase (MT1-MMP). CSE-treated mouse aneurysms showed increased aneurysm size with increased TPM infiltration and protease expression compared to non-CSE-treated mouse aneurysms. CONCLUSIONS: These results suggest that CSE intensifies OCG in macrophages and promotes arterial aneurysmal progression.

Digoxin Attenuates Receptor Activation of NF-κB Ligand-Induced Osteoclastogenesis in Macrophages.

BACKGROUND: Even though hypoxia-inducible factor-1α (HIF-1α) is among the transcriptional factors demonstrated to contribute to the formation of abdominal aortic aneurysms (AAAs), the precise mechanism has been unclear. Digoxin is known as an inhibitor of HIF-1α, and shows a protective effect against the progression of AAAs. OBJECTIVES: We tested the effect of digoxin on osteoclastogenesis (OCG) and examined the pathway through which digoxin exerts inhibition of HIF-1α. MATERIALS AND METHODS: RAW 264.7 macrophage cells were cultured and stimulated by soluble receptor activator of NF-κB ligand (sRANKL) with or without digoxin. First, we tested the effect of digoxin to attenuate macrophage activation, which led to OCG, characterized by tartrate-resistant acid phosphatase (TRAP)-positive macrophages (TPMs). RESULTS: The activation of TPMs stimulated by sRANKL was attenuated by digoxin treatment. Furthermore, the receptor activator of NF-κB (RANK)/receptor activator of NF-κB ligand (RANKL) complex signaling pathway, which is stimulated by HIF-1α, was downregulated by digoxin treatment. CONCLUSIONS: These results show that digoxin attenuates OCG. By inhibition of HIF-1α, digoxin decreases OCG through the downregulation of the RANK/RANKL signaling pathway. Therefore, digoxin is a potential candidate for medical treatment of AAAs.

Osteoclast-Like Cells in Aneurysmal Disease Exhibit an Enhanced Proteolytic Phenotype.

Abdominal aortic aneurysm (AAA) is among the top 20 causes of death in the United States. Surgical repair is the gold standard for AAA treatment, therefore, there is a need for non-invasive therapeutic interventions. Aneurysms are more closely associated with the osteoclast-like catabolic degradation of the artery, rather than the osteoblast-like anabolic processes of arterial calcification. We have reported the presence of osteoclast-like cells (OLCs) in human and mouse aneurysmal tissues. The aim of this study was to examine OLCs from aneurysmal tissues as a source of degenerative proteases. Aneurysmal and control tissues from humans, and from the mouse CaPO4 and angiotensin II (AngII) disease models, were analyzed via flow cytometry and immunofluorescence for the expression of osteoclast markers. We found higher expression of the osteoclast markers tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-9 (MMP-9), and cathepsin K, and the signaling molecule, hypoxia-inducible factor-1α (HIF-1α), in aneurysmal tissue compared to controls. Aneurysmal tissues also contained more OLCs than controls. Additionally, more OLCs from aneurysms express HIF-1α, and produce more MMP-9 and cathepsin K, than myeloid cells from the same tissue. These data indicate that OLCs are a significant source of proteases known to be involved in aortic degradation, in which the HIF-1α signaling pathway may play an important role. Our findings suggest that OLCs may be an attractive target for non-surgical suppression of aneurysm formation due to their expression of degradative proteases.

RANKL-mediated osteoclastogenic differentiation of macrophages in the abdominal aorta of angiotensin II-infused apolipoprotein E knockout mice.

OBJECTIVE: Osteoclastogenic activation of macrophages (OCG) occurs in human abdominal aortic aneurysms (AAAs) and in calcium chloride-induced degenerative AAAs in mice, which have increased matrix metalloproteinase activity. As the activity of OCG in dissecting aneurysms is not clear, we tested the hypothesis that OCG contributes to angiotensin II (Ang II)-induced dissecting aneurysm (Ang II-induced AAA) in apolipoprotein E knockout mice. METHODS: AAAs were produced in apolipoprotein E knockout mice via the administration of Ang II. Additionally, receptor activator of nuclear factor kB ligand (RANKL)-neutralizing antibody (5 mg/kg) was administered to one group of mice 7 days prior to Ang II infusion. Aneurysmal sections were probed for presence of RANKL and tartrate-resistant acid phosphatase via immunohistochemistry and immunofluorescence staining. Mouse aortas were also examined for RANKL and matrix metalloproteinase 9 expression via Western blot. In vitro murine vascular smooth muscle cells (MOVAS) and murine macrophages (RAW 264.7) were analyzed for the expression of osteogenic factors via Western blot, qPCR, and flow cytometry in response to Ang II or RANKL stimulation. The signaling pathway that mediates Ang II-induced RANKL expression in MOVAS cells was also investigated via application of TG101348, a Janus kinase 2 (JAK2) inhibitor, and Western blot analysis. RESULTS: Immunohistochemical staining of Ang II-induced AAA sections revealed OCG as evidenced by increased RANKL and tartrate-resistant acid phosphatase expression compared with control mice. Immunofluorescence staining of AAA sections revealed co-localization of vascular smooth muscle cells and RANKL, revealing vascular smooth muscle cells as one potential source of RANKL. Systemic administration of RANKL-neutralizing antibody suppressed Ang II-induced AAA, with significant reduction of the maximum diameter of the abdominal aorta compared with vehicle controls (1.5 ± 0.4 mm vs 2.2 ± 0.2 mm). Ang II (1 µM) treatment induced a significant increase in RANKL messenger RNA expression levels in MOVAS cells compared with the vehicle control (1.0 ± 0.2 vs 2.8 ± 0.2). The activities of JAK2 and signal transducer and activator of transcription 5 (STAT5) were also significantly increased by Ang II treatment. Inhibition of JAK2/STAT5 suppressed Ang II-induced RANKL expression, suggesting the involvement of the JAK2/STAT5 signaling pathway. CONCLUSIONS: OCG with increased RANKL expression was present in Ang II-induced AAA, and neutralization of RANKL suppressed AAA formation. As neutralization of RANKL has been used clinically to treat osteoporosis and other osteoclast-related diseases, additional study of the effectiveness of RANKL neutralization in AAA is warranted.

Hyperglycemia attenuates receptor activator of NF-κB ligand-induced macrophage activation by suppressing insulin signaling.

BACKGROUND: Although male gender, aging, hypertension, dyslipidemia, and smoking are common risk factors for abdominal aortic aneurysm, diabetes mellitus is an independent negative risk factor. In aneurysm tissue, matrix metalloproteinases (MMPs) expressed by activated macrophages degrades extracellular matrix proteins. In our previous experimental study, we demonstrated that the aneurysmal formation and macrophage activity were suppressed by inhibiting mimicking hyperglycemia (HG) through upregulation of glucose-sensing nuclear receptor, Nr1h2. Here in this study, we focused on the role of HG-induced altered glucose uptake on macrophage activation. METHODS: RAW264.7 murine macrophage cells were pretreated in cultures containing HG (HG group, 15.5 mM) or normal glucose (NG) concentrations (NG group, 5.5 mM) for 7 d. The culture medium was then changed in both groups to NG conditions, and the cells were stimulated with recombinant murine soluble receptor activator of NF-κB ligand (sRANKL). Macrophage activation was confirmed by tartrate-resistant acid phosphatase (TRAP) staining. RESULTS: Compared with the NG group, MMP-9 expression in the HG group was significantly suppressed. Glucose uptake was increased in the NG group but not in the HG group during macrophage activation. To determine the mechanism of activation, we studied the expression and distribution of glucose transporters (Gluts) in the macrophages. Although Glut expression was unaffected by glucose pretreatment, membrane translocation of Glut-1 was significantly enhanced in macrophages in the NG group but not in the HG group during activation. Insulin receptor and insulin receptor substrate-1 (IRS-1) messenger RNA, known stimulate to membrane translocation of Gluts, were both decreased by the HG condition but not by the NG condition. CONCLUSIONS: HG pretreatment suppressed the macrophage activation. sRANKL increased macrophage glucose uptake at NG concentrations, which was impaired by HG pretreatment through the inhibition of Glut1 membrane translocation and the insulin receptor and IRS-1 gene transcription. These data suggest that HG suppressed macrophage activation, through attenuation of glucose uptake via the suppression of the membrane translocation of Glut1 and insulin signaling.

Osteoclastogenic Differentiation of Macrophages in the Development of Abdominal Aortic Aneurysms.

OBJECTIVE: Arterial calcification is common and contributes to the pathogenesis of occlusive vascular disease. Similar to the dynamics of bone, it is a tightly controlled process that maintains a balance between osteogenesis and osteolysis. However, whether calcium homeostasis plays a role in the development of aneurysms has not been explored. We hypothesized that macrophages differentiate into osteoclasts in aneurysmal arteries and that protease byproducts contribute to aneurysm pathophysiology. APPROACH AND RESULTS: We performed histological and immunohistochemical analyses and showed that macrophages positive for several osteoclast markers, including tartrate acid phosphatase, occur in great numbers in the human aneurysmal aorta, but very few occur in the human stenotic aorta and none in the nondiseased human aorta. Moreover, in situ zymography showed elevated protease activity in these cells compared with undifferentiated macrophages. Tumor necrosis factor-α and calcium phosphate stimulated this osteoclastogenic differentiation process through nuclear factor-κB, mitogen-activated protein kinases, and intracellular calcium signaling but not the receptor activator of the nuclear factor-κB ligand. Inhibition of osteoclastogenic differentiation by bisphosphonate inhibits aneurysm development in a mouse model. CONCLUSIONS: These results suggest that differentiation of macrophages into osteoclasts contributes to the pathophysiology of aneurysmal disease.

Postdischarge outcomes after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Perioperative outcomes after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA) have been rigorously studied; however, inpatient and postdischarge outcomes have not been separately analyzed. The objective of this study was to examine postdischarge 30-day outcomes after elective EVAR. METHODS: Patients who underwent an elective EVAR for AAA (n = 11,229) were identified from the American College of Surgeons 2005-2010 National Surgical Quality Improvement Project database. Univariable and multivariable logistic regression analyses were performed. RESULTS: The median length of hospital stay was 2 days (interquartile range, 1-3 days). Overall 30-day mortality was 1.0% (n = 117), with 31% (n = 36) of the patients dying after discharge. Overall 30-day morbidity was 10.7% (n = 1204), with 40% (n = 500) of the morbidities being postdischarge. The median time of death and complication was 9 and 3 days, respectively, after surgery. Eighty-eight percent of the wound infections (n = 205 of 234), 33% of pneumonia (n = 44 of 133), and 55% of venous thromboembolism (n = 36 of 65) were postdischarge. Multivariable analyses showed age, congestive heart failure, admission from nursing facility, postoperative pneumonia, myocardial infarction, and renal failure were independently associated with postdischarge mortality, and peripheral arterial disease, female gender, previous cardiac surgery, age, smoking, and diabetes with postdischarge morbidity (P < .05 for all). CONCLUSIONS: Patient characteristics associated with a higher risk for postdischarge adverse events after EVAR were identified. Whether improved predischarge surveillance and close postdischarge follow-up of identified high-risk patients will further improve 30-day outcomes after EVAR needs to be prospectively studied.

The United States StuDy for EvalUating EndovasculaR TreAtments of Lesions in the Superficial Femoral Artery and Proximal Popliteal By usIng the Protégé EverfLex NitInol STent SYstem II (DURABILITY II).

OBJECTIVE: Angioplasty and stenting are options for revascularization of symptomatic femoral popliteal disease. Although angioplasty alone is effective in short lesions, longer lesions are often treated with stents. Multiple overlapping stents are expensive and may be associated with stent fracture. This trial evaluated the safety and efficacy of a single self-expanding stent up to 20 cm in length in patients with atherosclerotic disease of the superficial femoral artery (SFA) and proximal popliteal artery. METHODS: Patients with lesions >4 cm and <18 cm were enrolled in this nonrandomized, prospective, multicenter trial that evaluated the Protégé EverFlex Self-Expanding Peripheral Stent System (Covidien, Plymouth, Minn). The study's primary end points were the 30-day major adverse event rate and duplex ultrasound-assessed patency at 1 year. These were compared with published performance goals. A preplanned analysis was conducted for the primary effectiveness end points at 1 year. Follow-up, including history, ankle-brachial index, patient-reported outcomes, duplex ultrasound assessment, and radiographs, is planned through 3 years. There was core laboratory review of angiograms, ultrasound scans, and plain radiographs. A subgroup of patients was studied with graded treadmill testing. RESULTS: The study enrolled 287 patients (66% male; mean age, 68 years) with stenotic, restenotic, or occluded lesions of the SFA at 44 investigational sites in the United States and Europe. Systemic comorbidities included hypertension (88%), hyperlipidemia (86%), diabetes (43%), and prior SFA intervention (41%). The mean lesion length measured by the core laboratory was 89 mm. The mean normal-to-normal lesion length measured by sites was 110 mm. A total of 303 stents were implanted, and 95% of patients received a single stent. No major adverse events occurred at 30 days. At 1 year, primary outcome of duplex ultrasound stent patency was 67.7% in evaluable patients, and among 1-year secondary outcomes, the mean ankle-brachial index increased by 0.25. Walking Improvement Questionnaire scores improved in pain by 33.7, distance by 37.1, speed by 18.6, and stair climbing by 24.7. The Kaplan-Meier estimate of primary patency was 77.2%, primary assisted patency was 86.9%, and secondary patency was 87.3%. Rutherford clinical category improved in 83.5% of patients. Stent fracture rate was 0.4%. Matched absolute claudication distance was 412 feet greater and was not statistically different in this subgroup of 29 individuals. CONCLUSIONS: The results of DURABILITY II (StuDy for EvalUating EndovasculaR TreAtments of Lesions in the Superficial Femoral Artery and Proximal Popliteal By usIng the Protégé EverfLex NitInol Stent SYstem II) suggest that a new single stent strategy is safe and effective for the treatment of long lesions of the SFA and proximal popliteal arteries at 1 year.

Elevated protein kinase C-δ contributes to aneurysm pathogenesis through stimulation of apoptosis and inflammatory signaling.

OBJECTIVE: Apoptosis of smooth muscle cells (SMCs) is a prominent pathological characteristic of abdominal aortic aneurysm (AAA). We have previously shown that SMC apoptosis stimulates proinflammatory signaling in a mouse model of AAA. Here, we test whether protein kinase C-δ (PKCδ), an apoptotic mediator, participates in the pathogenesis of AAA by regulating apoptosis and proinflammatory signals. METHODS AND RESULTS: Mouse experimental AAA is induced by perivascular administration of CaCl(2). Mice deficient in PKCδ exhibit a profound reduction in aneurysmal expansion, SMC apoptosis, and transmural inflammation as compared with wild-type littermates. Delivery of PKCδ to the aortic wall of PKCδ(-/-) mice restores aneurysm, whereas overexpression of a dominant negative PKCδ mutant in the aorta of wild-type mice attenuates aneurysm. In vitro, PKCδ(-/-) aortic SMCs exhibit significantly impaired monocyte chemoattractant protein-1 production. Ectopic administration of recombinant monocyte chemoattractant protein-1 to the arterial wall of PKCδ(-/-) mice restores inflammatory response and aneurysm development. CONCLUSIONS: PKCδ is an important signaling mediator for SMC apoptosis and inflammation in a mouse model of AAA. By stimulating monocyte chemoattractant protein-1 expression in aortic SMCs, upregulated PKCδ exacerbates the inflammatory process, in turn perpetuating elastin degradation and aneurysmal dilatation. Inhibition of PKCδ may serve as a potential therapeutic strategy for AAA.

Current status of medical treatment for abdominal aortic aneurysm.

Although cardiovascular disease is widely recognized as the leading cause of death, a lesser known fact is that aortic aneurysm is the 15th leading cause of death over the age of 65 years in the USA. The golden standard of the treatments are invasive interventions either with open surgical repair (OS) or endovascular aneurysm repair (EVAR). The concept of medical treatment is to prevent abdominal aortic aneurysm (AAA) from rupture and avoid surgical treatment by preventing aneurysm enlargement or even reducing aneurysm size. Matrix metalloproteinases (MMP) are structurally related metalloendopeptidases that can degrade the extracellular matrix and is thought to play important roles in AAA. There are many proposed pharmacological treatments including: ß-blockers, angiotensin-converting enzyme inhibitor (ACE inhibitors), angiotensin-receptor blocker (ARB), statins, macrolides and, doxycycline, an inhibitor of the MMP. The latter is a potential promising drug as medical treatment for AAA and the Non-invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA(3)CT) is currently ongoing in the USA. Here, the pathophysiology and potential medical therapy for AAA will be reviewed.