The inflammasome and caspase-1 activation: a new mechanism underlying increased inflammatory activity in human visceral adipose tissue.

The immune competent abdominal adipose tissue, either stored viscerally [visceral adipose tissue (VAT)] or sc [sc adipose tissue (SAT)], has been identified as a source of IL-1ß and IL-18. To become active, the proforms of these cytokines require processing by caspase-1, which itself is mediated by the inflammasome. In this descriptive study, we investigate the expression of inflammasome components and caspase-1 in human fat and determine whether caspase-1 activity contributes to the enhanced inflammatory status of VAT. Paired SAT and VAT biopsies from 10 overweight subjects (body mass index, 25-28 kg/m(2)) were used to study the cellular composition and the intrinsic inflammatory capacity of both adipose tissue depots. The percentage of CD8(+) T cells within the lymphocyte fraction was significantly higher in VAT compared with SAT (41.6 vs. 30.4%; P < 0.05). Adipose tissue cultures showed a higher release of IL-1ß (10-fold; P < 0.05), IL-18 (3-fold; P < 0.05), and IL-6 and IL-8 (3-fold, P < 0.05; and 4-fold, P < 0.05, respectively) from VAT compared with SAT that was significantly reduced by inhibiting caspase-1 activity. In addition, caspase-1 activity was 3-fold (P < 0.05) higher in VAT compared with SAT, together with an increase in the protein levels of the inflammasome members apoptosis-associated speck-like protein containing a C-terminal caspase-recruitment domain (2-fold; P < 0.05) and nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (2-fold; nonsignificant). Finally, caspase-1 activity levels were positively correlated with the percentage of CD8(+) T cells present in adipose tissue. Our results show that caspase-1 and nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 inflammasome members are abundantly present in human VAT. The increased intrinsic caspase-1 activity in VAT represents a novel and specific inflammatory pathway that may determine the proinflammatory character of this specific depot.

Current role of imaging in diagnosing aortic graft infections.

Vascular prosthetic graft infection is a rare but serious complication after aortic graft replacement, with high morbidity and mortality rates. Therefore, adequate diagnostics are needed to detect and treat these infections as early as possible. Several imaging modalities provide different diagnostic values for detecting prosthetic graft infection. Previous studies reported on the diagnostic value of ultrasound, computed tomography imaging, magnetic resonance imaging, fluorodeoxyglucose-positron emission tomography, and single-photon emission computed tomography. In addition, adjunctive studies on new and promising techniques to detect prosthetic graft infection (eg, bio-optical imaging and target imaging with nuclear techniques) have also been investigated. This review provides a summary of noninvasive imaging modalities and their diagnostic values in order to evaluate and treat possible vascular graft infections as early as possible.

Impact of dynamic computed tomographic angiography on endograft sizing for endovascular aneurysm repair.

PURPOSE: To quantify dynamic changes in aortoiliac dimensions using dynamic electrocardiographically (ECG)-gated computed tomographic angiography (CTA) and to investigate any potential impact on preoperative endograft sizing in relation to observer variability. METHODS: Dynamic ECG-gated CTA was performed in 18 patients with abdominal aortic aneurysms. Postprocessing resulted in 11 datasets per patient: 1 static CTA and 10 dynamic CTA series. Vessel diameter, length, and angulation were measured for all phases of the cardiac cycle. The differences between diastolic and systolic aneurysm dimensions were analyzed for significance using paired t tests. To assess intraobserver variability, 20 randomly selected datasets were analyzed twice. Intraobserver repeatability coefficients (RC) were calculated using Bland-Altman analysis. RESULTS: Mean aortic diameter at the proximal neck was 21.4+/-3.0 mm at diastole and 23.2+/-2.9 mm at systole, a mean increase of 1.8+/-0.4 mm (8.5%, p<0.01). The RC for the aortic diameter at the level of the proximal aneurysm neck was 1.9 mm (8.9%). At the distal sealing zones, the mean increase in diameter was 1.7+/-0.3 mm (14.1%, p<0.01) for the right and 1.8+/-0.5 mm (14.2%, p<0.01) for the left common iliac artery (CIA). At both distal sealing zones, the mean increase in CIA diameter exceeded the RC (10.0% for the right CIA and 12.6% for the left CIA). CONCLUSION: The observed changes in aneurysm dimension during the cardiac cycle are small and in the range of intraobserver variability, so dynamic changes in proximal aneurysm neck diameter and aneurysm length likely have little impact on preoperative endograft selection. However, changes in diameter at the distal sealing zones may be relevant to sizing, so distal oversizing of up to 20% should be considered to prevent distal type I endoleak.

Incidental finding of malignancy in patients preoperatively evaluated for aneurysm wall pathology using PET/CT.

Preoperative positron emission tomography/computed tomography (PET/CT) was performed in 26 consecutive patients considered fit for aneurysm repair. Besides information on aneurysm wall pathology, PET/CT identified 6 patients with concomitant malignancy. As a result of this coincidental finding, the operation was postponed in 2 patients and cancelled in 1. Although previous studies have shown that PET/CT might affect patient selection based on aneurysm wall inflammation, our preliminary results show a big impact on patient management as a result of the sensitivity of PET/CT for detecting malignancy. Future larger studies are warranted to investigate the effect and cost effectiveness of routine PET/CT in abdominal aortic aneurysm (AAA) patients.