Reduced lung function in patients with abdominal aortic aneurysm is associated with activation of inflammation and hemostasis, not smoking or cardiovascular disease

Potential of Disease-Modifying Anti-Rheumatic Drugs to Limit Abdominal Aortic Aneurysm Growth

Inflammation is strongly implicated in the pathogenesis of abdominal aortic aneurysms (AAA). This review examined the potential role of biologic disease-modifying anti-rheumatic drugs (bDMARDs) as repurposed drugs for treating AAA. Published evidence from clinical and preclinical studies was examined. Findings from animal models suggested that a deficiency or inhibition of tumour necrosis factor-α (TNF-α) (standard mean difference (SMD): −8.37, 95% confidence interval (CI): −9.92, −6.82), interleukin (IL)-6 (SMD: −1.44, 95% CI: −2.85, −0.04) and IL-17 (SMD: −3.36, 95% CI: −4.21, −2.50) led to a significantly smaller AAA diameter compared to controls. Human AAA tissue samples had significantly increased TNF-α (SMD: 1.68, 95% CI: 0.87, 2.49), IL-1β (SMD: 1.93, 95% CI: 1.08, 2.79), IL-6 (SMD: 2.56, 95% CI: 1.79, 3.33) and IL-17 (SMD: 6.28, 95% CI: 3.57, 8.99) levels compared to non-AAA controls. In human serum, TNF-α (SMD: 1.11, 95% CI: 0.25, 1.97) and IL-6 (SMD: 1.42, 95% CI: 0.91, 1.92) levels were significantly elevated compared to non-AAA controls. These findings implicate TNF-α, IL-17 and IL-6 in AAA pathogenesis. Randomised controlled trials testing the value of bDMARDs in limiting AAA growth may be warranted.

Fibrinogen, a Promising Marker to Evaluate Severity and Prognosis of Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Retrospective Observational Study

Background

Fibrinogen is increasingly being studied as an inflammatory biomarker in chronic obstructive pulmonary disease (COPD), but there are limited data on the role of fibrinogen in assessing the severity of acute exacerbation of COPD (AECOPD). This study aimed to explore whether circulating fibrinogen could be used as a surrogate to measure the severity and predict the prognosis of AECOPD.

Methods

A total of 535 AECOPD patients diagnosed at our center from January 2016 to June 2021 were retrospectively enrolled in this study. The electronic medical record of each patient was retrieved to collect data on baseline characteristics and laboratory parameters, as well as the use of noninvasive positive-pressure ventilation (NPPV) and prognosis. Multiple linear regression analysis was used to identify independent factors associated with circulating fibrinogen values. Receiver-operating characteristic curve and multivariate logistic regression analysis were applied to further verify the use of fibrinogen to predict NPPV failure.

Results

Compared to patients with fibrinogen <4 g/L, patients with increased fibrinogen levels (>4 g/L) tended to have elevated inflammatory response and higher incidence of DVT/PTE, emphysema, pneumonia, and atherosclerosis. In addition, fibrinogen levels in NPPV-failure patients were significantly higher than non-NPPV patients and NPPV-success ones. The presence of emphysema, pneumonia, and history of long-term oxygen therapy and higher CRP levels and leukocyte counts were independent risk factors associated with increased fibrinogen levels in AECOPD. Furthermore, our data indicated that fibrinogen could be considered as a reliable biomarker to predict NPPV failure (AUC, 0.899, 95% CI 0.846–0.952), with an OR of 7.702 (95% CI 2.984–19.875; P<0.001).

Conclusion

The level of circulating fibrinogen can be used to measure severity of AECOPD, and among AECOPD patients managed with NPPV, fibrinogen >3.55 g/L can independently predict NPPV failure.

Dynamic Changes in Coagulation Function in Patients With Pneumonia Under Admission and Non-admission Treatment

Objective: We aimed to explore the dynamic changes in coagulation function and the effect of age on coagulation function in patients with pneumonia under admission and non-admission treatment. Methods: We included 178 confirmed adult inpatients with COVID-19 from Wuhan Union Hospital Affiliated to Huazhong University of Science and Technology (Wuhan, China). Patients were classified into common types, and all were cured and discharged after hospitalization. We recorded the time of the first clinical symptoms of the patients and performed blood coagulation tests at the time of admission and after admission. In total, eight factors (TT, FIB, INR, APTT, PT, DD, ATIII, and FDP) were analyzed. Patients were classified into four groups according to the time from the first symptom onset to hospital admission for comparative analysis. The patients who were admitted within 2 weeks of disease onset were analyzed for the dynamic changes in their blood coagulation tests. Further division into two groups, one group comprising patients admitted to the hospital within 2 weeks after the onset of disease and the other comprising patients admitted to the hospital 2 weeks after disease onset, was performed to form two groups based on whether the patient ages were over or under 55 years. Chi-square tests and T tests were used to explore the dynamic changes in coagulation function and the influence of age on the results of coagulation function tests. Results: A total of 178 inpatients, 34 of whom underwent dynamic detection, were included in this analysis. We divided these patients into four groups according to the interval between the onset of COVID-19 pneumonia and the time to admission in the hospital: the 1-7 days (group 1), 8-14 days (group 2), 15-21 days (group 3), and >21-days (group 4). Eight factors all increased within 2 weeks after onset and gradually decreased to normal 2 weeks before the patient was admitted. The changes in coagulation function of patients admitted to the hospital were similar. After being admitted to the hospital, the most significant decreases among the eight factors were between week 2 and 3. There were distinct differences among the eight factors between people older than 55 years and those younger than 55 years. In the first 2 weeks after being admitted, the levels of the eight factors in patients >55 years were significantly higher than those in patients <55 years, and after another 2 weeks of treatment, the factor levels in both age groups returned to normal. Conclusion: The eight factors all increased within 2 weeks after onset and gradually decreased to normal after 2 weeks regardless of treatment. Compared with patients younger than 55 years, patients older than 55 years have greater changes in their blood coagulation test values.

Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis?

BACKGROUND

Abdominal aortic aneurysms (AAAs) represent a complex multifactorial hemodynamic, thrombotic, and inflammatory process that can ultimately result in aortic rupture and death. Despite improved screening and surgical management of AAAs, the mortality rates have remained high after rupture, and little progress has occurred in the development of nonoperative treatments. Intraluminal thrombus (ILT) is present in most AAAs and might be involved in AAA pathogenesis. The present review examined the latest clinical and experimental evidence for possible involvement of the ILT in AAA growth and rupture.

METHODS

A literature review was performed after a search of the PubMed database from 2012 to June 2020 using the terms "abdominal aortic aneurysm" and "intraluminal thrombus."

RESULTS

The structure, composition, and hemodynamics of ILT formation and propagation were reviewed in relation to the hemostatic and proteolytic factors favoring ILT deposition. The potential effects of the ILT on AAA wall degeneration and rupture, including a review of the current controversies regarding the position, thickness, and composition of ILT, are presented. Although initially potentially protective against increased wall stress, increasing evidence has shown that an increased volume and greater age of the ILT have direct detrimental effects on aortic wall integrity, which might predispose to an increased rupture risk.

CONCLUSIONS

ILT does not appear to be an innocent bystander in AAA pathophysiology. However, its exact role remains elusive and controversial. Despite computational evidence of a possible protective role of the ILT in reducing wall stress, increasing evidence has shown that the ILT promotes AAA wall degeneration in humans and in animal models. Further research, with large animal models and with more chronic ILT is crucial for a better understanding of the role of the ILT in AAAs and for the potential development of targeted therapies to slow or halt AAA progression.

Comorbidities Associated with Large Abdominal Aortic Aneurysms

Background  Abdominal aortic aneurysm has become increasingly important owing to demographic changes. Some other diseases, for example, cholecystolithiasis, chronic obstructive pulmonary disease, and hernias, seem to co-occur with abdominal aortic aneurysm. The aim of this retrospective analysis was to identify new comorbidities associated with abdominal aortic aneurysm.

Methods  We compared 100 patients with abdominal aortic aneurysms and 100 control patients. Their preoperative computed tomographic scans were examined by two investigators independently, for the presence of hernias, diverticulosis, and cholecystolithiasis. Medical records were also reviewed. Statistical analysis was performed using univariate analysis and multiple logistic regression analysis.

Results  The aneurysm group had a higher frequency of diverticulosis ( p  = 0.008). There was no significant difference in the occurrence of hernia ( p  = 0.073) or cholecystolithiasis ( p  = 1.00). Aneurysm patients had a significantly higher American Society of Anesthesiology score (2.84 vs. 2.63; p  = 0.015) and were more likely to have coronary artery disease ( p  < 0.001), congestive heart failure ( p  < 0.001), or chronic obstructive pulmonary disease ( p  < 0.001). Aneurysm patients were more likely to be former ( p  = 0.034) or current ( p  = 0.006) smokers and had a significantly higher number of pack years ( p  < 0.001). Aneurysm patients also had a significantly poorer lung function. In multivariate analysis, the following factors were associated with aneurysms: chronic obstructive pulmonary disease (odds ratio, OR = 12.24; p  = 0.002), current smoking (OR = 4.14; p  = 0.002), and coronary artery disease (OR = 2.60; p  = 0.020).

Conclusions  Our comprehensive analysis identified several comorbidities associated with abdominal aortic aneurysms. These results could help to recognize aneurysms earlier by targeting individuals with these comorbidities for screening.

Association Between Perioperative Fibrinogen Levels and the Midterm Outcome in Patients Undergoing Elective Endovascular Repair of Abdominal Aortic Aneurysms

BACKGROUND

We investigated the potential association between perioperative fibrinogen levels and outcome in patients undergoing elective endovascular abdominal aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs).

METHODS

Consecutive patients with an intact AAA undergoing elective EVAR with a specific bifurcated endograft (Endurant, Medtronic) were recruited between December 2012 and October 2016. Preoperative and 24-hr postoperative fibrinogen levels were recorded, and potential associations with outcome were tested. Primary outcome measures included endoleaks, lower limb ischemic complications, including endograft limb occlusion, and aneurysm-related reinterventions.

RESULTS

Ninety-four patients (91 male, mean age 71.8 ± 8.0 years) with an intact AAA were enrolled in the study. The technical success was 98% (2 failures: 1 type Ia endoleak on completion angiography, 1 lower limb ischemia immediately postoperatively requiring femoral endarterectomy). There was 1 death during the first 30 days due to myocardial infarction (1%). Another patient died 15 months after the procedure from cardiac causes. During the existing follow-up (mean 14.8 ± 14.3 months), 14 patients (15%) developed an endoleak (4, type Ia endoleak and 10, type II endoleak), 6 patients (6.3%) had lower limb ischemia/endograft limb occlusion, and 10 patients (10.6%) required reintervention. Compared with the preoperative values, no significant change occurred with regard to the fibrinogen levels 24 hr after procedure (mean preoperative fibrinogen 360 ± 101 mg/dl vs 24-hr postoperative fibrinogen 349 ± 105 mg/dl, P = 0.1). Neither preoperative nor 24-hr postoperative fibrinogen levels were significantly associated with the development of endoleaks, lower limb ischemia, or reinterventions. However, the difference in fibrinogen levels (baseline to 24 hr after procedure) was significantly higher in patients with endoleaks (median -65 mg/dl vs. 15 mg/dl, P = 0.04).

CONCLUSIONS

Perioperative fibrinogen levels may play a role in predicting midterm outcomes in patients undergoing elective EVAR and appears to be associated, directly or indirectly, with the development of endoleaks. Further studies are needed to investigate these findings and explore future therapeutic implications.

von Willebrand factor deficiency does not influence angiotensin II-induced abdominal aortic aneurysm formation in mice

Abdominal aortic aneurysm (AAA) refers to a localized dilation of the abdominal aorta that exceeds the normal diameter by 50%. AAA pathophysiology is characterized by progressive inflammation, vessel wall destabilization and thrombus formation. Our aim was to investigate the potential involvement of von Willebrand factor (VWF), a thrombo-inflammatory plasma protein, in AAA pathophysiology using a dissection-based and angiotensin II infusion-induced AAA mouse model. AAA formation was induced in both wild-type and VWF-deficient mice by subcutaneous implantation of an osmotic pump, continuously releasing 1000 ng/kg/min angiotensin II. Survival was monitored, but no significant difference was observed between both groups. After 28 days, the suprarenal aortic segment of the surviving mice was harvested. Both AAA incidence and severity were similar in wild-type and VWF-deficient mice, indicating that AAA formation was not significantly influenced by the absence of VWF. Although VWF plasma levels increased after the infusion period, these increases were not correlated with AAA progression. Also detailed histological analyses of important AAA hallmarks, including elastic degradation, intramural thrombus formation and leukocyte infiltration, did not reveal differences between both groups. These data suggest that, at least in the angiotensin II infusion-induced AAA mouse model, the role of VWF in AAA pathophysiology is limited.

Fibrinogen as a potential biomarker for clinical phenotype in patients with chronic obstructive pulmonary disease

Background

Under the Food and Drug Administration's drug development tool qualification program, fibrinogen is the first biomarker drug development tool used in chronic obstructive pulmonary disease (COPD). However, the correlation between fibrinogen and exacerbations among Korean patients with COPD remains unclear.

Methods

In this retrospective cross-sectional study, we included patients with COPD for whom plasma fibrinogen assessment results, without exacerbation, were available. Then, we compared subgroups according to fibrinogen level (threshold: 350 mg/dL). We used multivariate linear regression analysis to investigate the clinical phenotype of COPD with high fibrinogen level, analyzed the correlation between the COPD severity indexes and fibrinogen level.

Results

Of 140 patients, we confirmed 48 (34.3%) patients in the high-level fibrinogen group. The high-level group demonstrated a medical history of more exacerbations than the low-level group. Lung functions [forced expiratory volume in 1 s (FEV₁), forced vital capacity, and 6-minute walk distance] were more deteriorated in the high-level group. Multivariate regression analysis revealed that fibrinogen level was associated with high COPD assessment test score, and experience of exacerbation. Fibrinogen level exhibited a statistically significant positive correlation with COPD severity indexes.

Conclusions

High fibrinogen level seems to reflect frequent exacerbation and severe symptomatic phenotypes in Korean patients with COPD.

Tissue factor levels and the fibrinolytic system in thin and thick intraluminal thrombus and underlying walls of abdominal aortic aneurysms

BACKGROUND

The hemostatic system cooperates with proteolytic degradation in processes allowing abdominal aortic aneurysm (AAA) formation. In previous studies, it has been suggested that aneurysm rupture depends on intraluminal thrombus (ILT) thickness, which varies across each individual aneurysm. We hypothesized that hemostatic components differentially accumulate in AAA tissue in relation to ILT thickness. Thick (A1) and thin (B1) segments of ILTs and aneurysm wall sections A (adjacent to A1) and B (adjacent to B1) from one aneurysm sac were taken from 35 patients undergoing elective repair.

METHODS

Factor levels were measured using enzyme-linked immunosorbent assay of protein extract.

RESULTS

Tissue factor (TF) activities were significantly higher in thinner segments of AAA (B1 vs A1, P = .003; B vs A, P < .001; B vs A1, P < .001; B vs B1, P = .001). Significantly higher tissue plasminogen activator was found in thick thrombus-covered wall segments (A) than in B, A1, and B1 (P = .015, P < .001, and P < .001, respectively). Plasminogen concentrations were highest in ILT. Concentrations of α₂-antiplasmin in thin ILT adjacent walls (B) were higher compared with wall (A) adjacent to thick ILT (P = .021) and thick ILT (A1; P < .001). Significant correlations between levels of different factors were mostly found in thick ILT (A1). However, no correlations were found at B sites, except for a correlation between plasmin and TF activities (r = 0.55; P = .004).

CONCLUSIONS

These results suggest that higher TF activities are present in thinner AAA regions. These parameters and local fibrinolysis may be part of the processes leading to destruction of the aneurysm wall.

Prospective study of lung function and abdominal aortic aneurysm risk: The Atherosclerosis Risk in Communities study

BACKGROUND AND AIMS

No prospective study has investigated whether individuals with respiratory impairments, including chronic obstructive pulmonary disease (COPD) and restrictive lung disease (RLD), are at increased risk of abdominal aortic aneurysm (AAA). We aimed to prospectively investigate whether those respiratory impairments are associated with increased AAA risk.

METHODS

In 1987-1989, the Atherosclerosis Risk in Communities (ARIC) study followed 14,269 participants aged 45-64 years, without a history of AAA surgery, through 2011. Participants were classified into four groups, "COPD" [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)

RESULTS

During the 284,969 person-years of follow-up, 534 incident AAA events were documented. In an age, sex, and race-adjusted proportional hazards model, individuals with respiratory impairments had a significantly higher risk of AAA than the normal reference group. After adjustment for AAA risk factors, including smoking status and pack-years of smoking, AAA risk was no longer significant in the respiratory symptoms with normal spirometry group [HR (95% CI), 1.25 (0.98-1.60)], but was still increased in the other two groups [RLD: 1.45 (1.04-2.02) and COPD: 1.66 (1.34-2.05)]. Moreover, continuous measures of FEV1/FVC, FEV1 and FVC were associated inversely with risk of AAA.

CONCLUSIONS

In the prospective population-based cohort study, obstructive and restrictive spirometric patterns were associated with increased risk of AAA independent of smoking, suggesting that COPD and RLD may increase the risk of AAA.

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Key Words

• Abdominal aortic aneurysm
• COPD
• Epidemiology
• Lung function

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MESH Headings

• Aortic Aneurysm, Abdominal/diagnostic imaging
• Aortic Aneurysm, Abdominal/epidemiology
• Female
• Forced Expiratory Volume
• Humans
• Incidence
• Lung/physiopathology
• Male
• Middle Aged
• Prognosis
• Prospective Studies
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Pulmonary Disease, Chronic Obstructive/physiopathology
• Risk Assessment
• Risk Factors
• Spirometry
• Time Factors
• United States/epidemiology
• Vital Capacity

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Grants

• HHSN268201100012C NHLBI NIH HHS
• HHSN268201100010C NHLBI NIH HHS
• HHSN268201100008C NHLBI NIH HHS
• HHSN268201100007C NHLBI NIH HHS
• HHSN268201100011I NHLBI NIH HHS
• HHSN268201100011C NHLBI NIH HHS
• HHSN268201000011C NHLBI NIH HHS
• HHSN268201100006C NHLBI NIH HHS
• HHSN268201100005I NHLBI NIH HHS
• R01 HL103695 NHLBI NIH HHS
• HHSN268201100009I NHLBI NIH HHS
• HHSN268201000012C NHLBI NIH HHS
• HHSN268201100005G NHLBI NIH HHS
• HHSN268201100008I NHLBI NIH HHS
• HHSN268201100009C NHLBI NIH HHS
• HHSN268201100005C NHLBI NIH HHS
• HHSN268201100007I NHLBI NIH HHS
• HHSN268201000010C NHLBI NIH HHS

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Affiliation(s)

Yasuhiko Kubota Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
Aaron R Folsom Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA
Kunihiro Matsushita Department of Epidemiology and the Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
David Couper Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
Weihong Tang Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA

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The UK EndoVascular Aneurysm Repair (EVAR) randomised controlled trials: long-term follow-up and cost-effectiveness analysis

BACKGROUND

Short-term survival benefits of endovascular aneurysm repair (EVAR) compared with open repair (OR) of intact abdominal aortic aneurysms have been shown in randomised trials, but this early survival benefit is soon lost. Survival benefit of EVAR was unclear at follow-up to 10 years.

OBJECTIVE

To assess the long-term efficacy of EVAR against OR in patients deemed fit and suitable for both procedures (EVAR trial 1; EVAR-1); and against no intervention in patients unfit for OR (EVAR trial 2; EVAR-2). To appraise the long-term significance of type II endoleak and define criteria for intervention.

DESIGN

Two national, multicentre randomised controlled trials: EVAR-1 and EVAR-2.

SETTING

Patients were recruited from 37 hospitals in the UK between 1 September 1999 and 31 August 2004.

PARTICIPANTS

Men and women aged ≥ 60 years with an aneurysm of ≥ 5.5 cm (as identified by computed tomography scanning), anatomically suitable and fit for OR were randomly assigned 1 : 1 to either EVAR (n = 626) or OR (n = 626) in EVAR-1 using computer-generated sequences at the trial hub. Patients considered unfit were randomly assigned to EVAR (n = 197) or no intervention (n = 207) in EVAR-2. There was no blinding.

INTERVENTIONS

EVAR, OR or no intervention.

MAIN OUTCOME MEASURES

The primary end points were total and aneurysm-related mortality until mid-2015 for both trials. Secondary outcomes for EVAR-1 were reinterventions, costs and cost-effectiveness.

RESULTS

In EVAR-1, over a mean of 12.7 years (standard deviation 1.5 years; maximum 15.8 years), we recorded 9.3 deaths per 100 person-years in the EVAR group and 8.9 deaths per 100 person-years in the OR group [adjusted hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.97 to 1.27; p = 0.14]. At 0-6 months after randomisation, patients in the EVAR group had a lower mortality (adjusted HR 0.61, 95% CI 0.37 to 1.02 for total mortality; HR 0.47, 95% CI 0.23 to 0.93 for aneurysm-related mortality; p = 0.031), but beyond 8 years of follow-up patients in the OR group had a significantly lower mortality (adjusted HR 1.25, 95% CI 1.00 to 1.56, p = 0.048 for total mortality; HR 5.82, 95% CI 1.64 to 20.65, p = 0.0064 for aneurysm-related mortality). The increased aneurysm-related mortality in the EVAR group after 8 years was mainly attributable to secondary aneurysm sac rupture, with increased cancer mortality also observed in the EVAR group. Overall, aneurysm reintervention rates were higher in the EVAR group than in the OR group, 4.1 and 1.7 per 100 person-years, respectively (p < 0.001), with reinterventions occurring throughout follow-up. The mean difference in costs over 14 years was £3798 (95% CI £2338 to £5258). Economic modelling based on the outcomes of the EVAR-1 trial showed that the cost per quality-adjusted life-year gained over the patient's lifetime exceeds conventional thresholds used in the UK. In EVAR-2, patients died at the same rate in both groups, but there was suggestion of lower aneurysm mortality in those who actually underwent EVAR. Type II endoleak itself is not associated with a higher rate of mortality.

LIMITATIONS

Devices used were implanted between 1999 and 2004. Newer devices might have better results. Later follow-up imaging declined, particularly for OR patients. Methodology to capture reinterventions changed mainly to record linkage through the Hospital Episode Statistics administrative data set from 2009.

CONCLUSIONS

EVAR has an early survival benefit but an inferior late survival benefit compared with OR, which needs to be addressed by lifelong surveillance of EVAR and reintervention if necessary. EVAR does not prolong life in patients unfit for OR. Type II endoleak alone is relatively benign.

FUTURE WORK

To find easier ways to monitor sac expansion to trigger timely reintervention.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN55703451.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and the results will be published in full in Health Technology Assessment; Vol. 22, No. 5. See the NIHR Journals Library website for further project information.

Muscles Susceptibility to Ischemia-Reperfusion Injuries Depends on Fiber Type Specific Antioxidant Level

Muscle injury resulting from ischemia-reperfusion largely aggravates patient prognosis but whether and how muscle phenotype modulates ischemia-reperfusion-induced mitochondrial dysfunction remains to be investigated. We challenged the hypothesis that glycolytic muscles are more prone to ischemia-reperfusion-induced injury than oxidative skeletal muscles. We therefore determined simultaneously the effect of 3 h of ischemia induced by aortic clamping followed by 2 h of reperfusion (IR, n = 11) on both gastrocnemius and soleus muscles, as compared to control animals (C, n = 11). Further, we investigated whether tempol, an antioxidant mimicking superoxide dismutase, might compensate a reduced defense system, likely characterizing glycolytic muscles (IR-Tempol, n = 7). In the glycolytic gastrocnemius muscle, as compared to control, ischemia-reperfusion significantly decreased mitochondrial respiration (-30.28 ± 6.16%, p = 0.003), increased reactive oxygen species production (+79.15 ± 28.72%, p = 0.04), and decreased reduced glutathione (-28.19 ± 6.80%, p = 0.011). Less deleterious effects were observed in the oxidative soleus muscle (-6.44 ± 6.30%, +4.32 ± 16.84%, and -8.07 ± 10.84%, respectively), characterized by enhanced antioxidant defenses (0.63 ± 0.05 in gastrocnemius vs. 1.24 ± 0.08 μmol L^-1 g^-1 in soleus). Further, when previously treated with tempol, glycolytic muscle was largely protected against the deleterious effects of ischemia-reperfusion. Thus, oxidative skeletal muscles are more protected than glycolytic ones against ischemia-reperfusion, thanks to their antioxidant pool. Such pivotal data support that susceptibility to ischemia-reperfusion-induced injury differs between organs, depending on their metabolic phenotypes. This suggests a need to adapt therapeutic strategies to the specific antioxidant power of the target organ to be protected.

Review: Systemic consequences of COPD

Chronic obstructive pulmonary disease (COPD) is a highly prevalent chronic lung condition, affecting ∼10% of adults over the age of 40 years in the western world. Research over the past 10 years has shown that COPD is more than just a lung disorder; it affects other end-organs including the cardiovascular and the musculoskeletal systems, making it a multi-component, multi-system disease. COPD increases the risk for ischemic heart disease, stroke, osteoporosis, cachexia, and muscle weakness by two to threefold, independent of other factors such as smoking and age. The mechanisms by which COPD affects these end-organs, however, are unclear. In this paper, we review some of the common and serious extra-pulmonary manifestations of COPD and the potential mechanisms by which they can be linked with COPD.

Inhibition of reactive oxygen species downregulates the MAPK pathway in rat spinal cord after limb ischemia reperfusion injury

INTRODUCTION

We examined the activity of mitogen-activated protein kinase (MAPK) family members, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, in rats pinal cord after hind limb ischemia reperfusion (IR) and analyzed the role of reactive oxygen species (ROS) as mediators of MAPK signaling under these conditions.

METHODS

In experiment 1, hind limb IR rats were treated intraperitoneally with one of following agents at 30 min before reperfusion: allopurinol (4, 40 mg/kg), superoxide dismutase (SOD, 4000 U/kg), N-nitro-l-arginine methyl ester (l-NAME, 10 mg/kg), or SOD (4000 U/kg) + l-NAME (10 mg/kg). In experiment 2, 5,10,15,20-tetrakis (N-methyl-4'-pyridyl) porphyrinato iron (III) (FeTMPyP) was administered intraperitoneally (1, 3, or 10 mg/kg) 30 min before reperfusion. After 3 d reperfusion period, the spinal cord (L4-6) was harvested to investigate MAPK signaling activity.

RESULTS

In experiment 1, p-ERK and p-JNK levels were significantly higher in the IR group than sham group. Administration of allopurinol, SOD, l-NAME, or SOD + l-NAME significantly reduced the IR-induced increase in p-ERK and p-JNK levels. There were no significant differences in p-p38 levels. In experiment 2, FeTMPyP significantly reduced the IR-induced increase in p-ERK and p-JNK levels in a dose-dependent manner.

CONCLUSIONS

Activation of ERK and JNK in the spinal cord was induced by hind limb IR and was not accompanied by p38 activation. IR-induced MAPK phosphorylation was reduced by inhibition of superoxide, nitric oxide, and peroxynitrite, indicating that ROS produced by hind limb IR mediate the activation of these signaling pathways in the spinal cord, potentially affecting distant organs.

Screening of COPD patients for abdominal aortic aneurysm

Purpose

Screening for abdominal aortic aneurysm (AAA) in “men aged over 65 years who have ever smoked” is a recommended policy. To reduce the number of screenings, it may be of value to define subgroups with a higher prevalence of AAA. Since chronic obstructive pulmonary disease (COPD) and AAA are associated with several common risk factors, this study investigates the prevalence of AAA in COPD patients.

Patients and methods

Patients with COPD were identified via the hospital information system. Inclusion criteria were: COPD stage I–IV, ability to give full consent, and age >18 years; exclusion criteria were: patient too obese for an ultrasound check, previously diagnosed AAA, prior surgery for AAA, or ethical grounds such as concomitant advanced malignant or end-stage disease. The primary endpoint of the study was an aortic diameter measured by ultrasound of ≥30 mm. Defined secondary endpoints were evaluated on the basis of medical records and interviews.

Results

Of the 1,180 identified COPD patients, 589 were included in this prospective study. In 22 patients (3.70%), the aortic diameter was ≥30 mm, representing an AAA prevalence of 6.72% among males aged >65 years. The risk of AAA increased with the following comorbidities/risk factors: male sex (odds ratio [OR] 2.98), coronary heart disease (OR 2.81), peripheral arterial occlusive disease (OR 2.47), hyperlipoproteinemia (OR 2.77), AAA in the family history (OR 3.95), and COPD stage I/II versus IV (OR 1.81).

Conclusion

The overall AAA prevalence of 3.7% in our group of COPD patients is similar to that of the general population aged >65 years. However, the frequency of AAA in male COPD patients aged >65 years is considerably higher (6.72%) and increased further still in those individuals with additional comorbidities/risk factors. Defining subgroups with a higher risk of AAA may increase the efficiency of screening.

Extracellular matrix defects in aneurysmal Fibulin-4 mice predispose to lung emphysema

Background

In this study we set out to investigate the clinically observed relationship between chronic obstructive pulmonary disease (COPD) and aortic aneurysms. We tested the hypothesis that an inherited deficiency of connective tissue might play a role in the combined development of pulmonary emphysema and vascular disease.

Methods

We first determined the prevalence of chronic obstructive pulmonary disease in a clinical cohort of aortic aneurysms patients and arterial occlusive disease patients. Subsequently, we used a combined approach comprising pathological, functional, molecular imaging, immunological and gene expression analysis to reveal the sequence of events that culminates in pulmonary emphysema in aneurysmal Fibulin-4 deficient (Fibulin-4^R) mice.

Results

Here we show that COPD is significantly more prevalent in aneurysm patients compared to arterial occlusive disease patients, independent of smoking, other clinical risk factors and inflammation. In addition, we demonstrate that aneurysmal Fibulin-4^R/R mice display severe developmental lung emphysema, whereas Fibulin-4^+/R mice acquire alveolar breakdown with age and upon infectious stress. This vicious circle is further exacerbated by the diminished antiprotease capacity of the lungs and ultimately results in the development of pulmonary emphysema.

Conclusions

Our experimental data identify genetic susceptibility to extracellular matrix degradation and secondary inflammation as the common mechanisms in both COPD and aneurysm formation.

Remote effects of lower limb ischemia-reperfusion: impaired lung, unchanged liver, and stimulated kidney oxidative capacities

Remote organ impairments are frequent and increase patient morbidity and mortality after lower limb ischemia-reperfusion (IR). We challenged the hypothesis that lower limb IR might also impair lung, renal, and liver mitochondrial respiration. Two-hour tourniquet-induced ischemia was performed on both hindlimbs, followed by a two-hour reperfusion period in C57BL6 mice. Lungs, liver and kidneys maximal mitochondrial respiration (V(max)), complexes II, III, and IV activity (V(succ)), and complex IV activity (V(TMPD)) were analyzed on isolated mitochondria. Lower limb IR decreased significantly lung V(max) (29.4 ± 3.3 versus 24 ± 3.7 μmol O2/min/g dry weight, resp.; P = 0.042) and tended to reduce V(succ) and V(TMPD). IR did not modify liver but increased kidneys mitochondrial respiration (79.5 ± 19.9 versus 108.6 ± 21.4, P = 0.035, and 126 ± 13.4 versus 142.4 ± 10.4 μmol O2/min/g dry weight for V(max) and V(succ), resp.). Kidneys mitochondrial coupling was increased after IR (6.5 ± 1.3 versus 8.8 ± 1.1, P = 0.008). There were no histological changes in liver and kidneys. Thus, lung mitochondrial dysfunction appears as a new early marker of hindlimb IR injuries in mice. Further studies will be useful to determine whether enhanced kidneys mitochondrial function allows postponing kidney impairment in lower limb IR setting.

Circulating interleukin-6 levels are associated with abdominal aortic aneurysm presence: a meta-analysis and meta-regression of case-control studies

BACKGROUND

In a number of relatively small-size studies, investigators have measured and compared circulating interleukin-6 (IL-6) levels in cases with abdominal aortic aneurysm (AAA) and controls without AAA to assess its possible role in the pathogenesis or progression of AAA. To summarize the present evidence for an association between circulating IL-6 levels and AAA presence, we performed a meta-analysis of case-control studies that compared circulating IL-6 levels between patients with AAA and subjects without AAA.

METHODS

MEDLINE and EMBASE were searched through December 2013 using Web-based search engines (PubMed and OVID). Eligible studies were case-control studies of patients with AAA and subjects without AAA reporting circulating IL-6 levels. For each study, data regarding plasma or serum IL-6 levels in both the AAA and control groups were used to generate standardized mean differences (SMDs) and 95% confidence intervals (CIs). Mixed-effects (unrestricted maximum likelihood) meta-regression analyses were performed to determine whether the differences in circulating IL-6 levels were modulated by the prespecified factors.

RESULTS

Our search identified 13 eligible studies enrolling a total of 1,029 cases with AAA and 924 controls without AAA. Pooled analysis of the 13 studies demonstrated significantly greater circulating IL-6 levels in the AAA group than those in the control group (random-effects SMD 0.59; 95% CI 0.37-0.80; P for effect < 0.00001; P for heterogeneity < 0.0000). The meta-regression coefficient for the mean age (P = 0.10196) and the proportion of current smokers (P = 0.29893) was not statistically significant. That for the mean AAA diameter, however, was significantly positive (coefficient 0.02789; 95% CI 0.00778-0.04800; P = 0.00657), and that for the proportion of men was significantly negative (coefficient -0.01823; 95% CI -0.03202 to -0.00445; P = 0.00952).

CONCLUSIONS

Circulating IL-6 levels are greater in patients with AAA than those in subjects without AAA, which suggest that greater circulating IL-6 levels are associated with AAA presence. As the mean AAA diameter and the proportion of men increase, circulating IL-6 levels in patients with AAA are respectively more and less greater than those in controls without AAA.

Interleukin-6 receptor pathways in abdominal aortic aneurysm

METHODS

We conducted a systematic review and meta-analysis of studies reporting circulating IL-6 in AAA, and new investigations of the association between a common non-synonymous functional variant (Asp358Ala) in the IL-6R gene (IL6R) and AAA, followed the analysis of the variant both in vitro and in vivo. Inflammation may play a role in the development of abdominal aortic aneurysms (AAA). Interleukin-6 (IL-6) signalling through its receptor (IL-6R) is one pathway that could be exploited pharmacologically. We investigated this using a Mendelian randomization approach.

RESULTS

Up to October 2011, we identified seven studies (869 cases, 851 controls). Meta-analysis demonstrated that AAA cases had higher levels of IL-6 than controls [standardized mean difference (SMD) = 0.46 SD, 95% CI = 0.25-0.66, I(2) = 70%, P = 1.1 × 10-5 random effects]. Meta-analysis of five studies (4524 cases/15 710 controls) demonstrated that rs7529229 (which tags the non-synonymous variant Asp358Ala, rs2228145) was associated with a lower risk of AAA, per Ala358 allele odds ratio 0.84, 95% CI: 0.80-0.89, I(2) = 0%, P = 2.7 × 10-11). In vitro analyses in lymphoblastoid cell lines demonstrated a reduction in the expression of downstream targets (STAT3, MYC and ICAM1) in response to IL-6 stimulation in Ala358 carriers.

CONCLUSIONS

A Mendelian randomization approach provides robust evidence that signalling via the IL-6R is likely to be a causal pathway in AAA. Drugs that inhibit IL-6R may play a role in AAA management.

The role of prostaglandin E2 in human vascular inflammation

Prostaglandins (PG) are the product of a cascade of enzymes such as cyclooxygenases and PG synthases. Among PG, PGE2 is produced by 3 isoforms of PGE synthase (PGES) and through activation of its cognate receptors (EP1-4), this PG is involved in the pathophysiology of vascular diseases. Some anti-inflammatory drugs (e.g. glucocorticoids, nonsteroidal anti-inflammatory drugs) interfere with its metabolism or effects. Vascular cells can initiate many of the responses associated with inflammation. In human vascular tissue, PGE2 is involved in many physiological processes, such as increasing vascular permeability, cell proliferation, cell migration and control of vascular smooth muscle tone. PGE2 has been shown to contribute to the pathogenesis of atherosclerosis, abdominal aortic aneurysm but also in physiologic/adaptive processes such as angiogenesis. Understanding the roles of PGE2 and its cognate receptors in vascular diseases could help to identify diagnostic and prognostic biomarkers. In addition, from these recent studies new promising therapeutic approaches like mPGES-1 inhibition and/or EP4-antagonism should be investigated.

Blood fibrinogen as a biomarker of chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a multicomponent condition that is characterised by airflow obstruction that is not fully reversible and is a major global cause of morbidity and mortality. The most widely used marker of disease severity and progression is FEV₁. However, FEV₁ correlates poorly with both symptoms and other measures of disease progression and thus there is an urgent need for other biological markers to better characterise individuals with COPD. Fibrinogen is an acute phase plasma protein that has emerged as a promising biomarker in COPD. Here we review the current clinical evidence linking fibrinogen with COPD and its associated co-morbidities and discuss its potential utility as a biomarker.

Methods

Searches for appropriate studies were undertaken on PubMed using search terms fibrinogen, COPD, emphysema, chronic bronchitis, FEV₁, cardiovascular disease, exacerbation and mortality.

Results

There is strong evidence of an association between fibrinogen and the presence of COPD, the presence and frequency of exacerbations and with mortality. Fibrinogen is associated with disease severity but does not predict lung function decline, a measure used as a surrogate for disease activity. The role of fibrinogen in identifying inflammatory co morbidities, particularly cardiovascular disease, remains unclear. Fibrinogen is reduced by p38 mitogen-activated protein kinase inhibitors in individuals with stable disease and by oral corticosteroids during exacerbations.

Conclusions

Fibrinogen is likely to be a useful biomarker to stratify individuals with COPD into those with a high or low risk of future exacerbations and may identify those with a higher risk of mortality.

Association analysis of genetic polymorphisms of factor V, factor VII and fibrinogen β chain genes with human abdominal aortic aneurysm

Increased activity of the coagulation system is associated with the increased risk of many arterial thrombotic diseases and atherosclerosis. The purpose of this study was to evaluate the influence of selected polymorphisms in genes coding for coagulation factor V (1691 G/A, the so-called Leiden mutation), factor VII (−323 0/10 bp insertion/deletion) and fibrinogen β chain (−455 G/A) on the risk of abdominal aortic aneurysm, a particular form of atherothrombosis. We conducted a case-control study of 153 Polish patients hospitalized due to abdominal aortic aneurysm (AAA) and compared the results to those obtained from matched healthy control subjects. The polymorphisms were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. The study revealed that individuals carrying heterozygous genotype GA for the fibrinogen β chain −455 G/A mutation had at least a 2-fold greater likelihood of AAA development compared to control subjects (OR=3.01; 95% CI 1.83–4.96). The cases possessing homozygous mutant genotype (AA) had no significant risk of developing AAA compared to the control subjects (OR=1.12; 95% CI 0.33–2.44; p=0.83). Concerning factor V 1691 G/A and factor VII −323 0/10 bp mutations, we did not find any statistically significant correlation between them and AAA occurrence. In conclusion, we suggest that the −455G/A polymorphism of the fibrinogen β chain gene is a potential genetic marker to identify the risk of AAA.

Novel aspects of the pathogenesis of aneurysms of the abdominal aorta in humans

Aneurysm of the abdominal aorta (AAA) is a particular, specifically localized form of atherothrombosis, providing a unique human model of this disease. The pathogenesis of AAA is characterized by a breakdown of the extracellular matrix due to an excessive proteolytic activity, leading to potential arterial wall rupture. The roles of matrix metalloproteinases and plasmin generation in progression of AAA have been demonstrated both in animal models and in clinical studies. In the present review, we highlight recent studies addressing the role of the haemoglobin-rich, intraluminal thrombus and the adventitial response in the development of human AAA. The intraluminal thrombus exerts its pathogenic effect through platelet activation, fibrin formation, binding of plasminogen and its activators, and trapping of erythrocytes and neutrophils, leading to oxidative and proteolytic injury of the arterial wall. These events occur mainly at the intraluminal thrombus-circulating blood interface, and pathological mediators are conveyed outwards, where they promote matrix degradation of the arterial wall. In response, neo-angiogenesis, phagocytosis by mononuclear cells, and a shift from innate to adaptive immunity in the adventitia are observed. Abdominal aortic aneurysm thus represents an accessible spatiotemporal model of human atherothrombotic progression towards clinical events, the study of which should allow further understanding of its pathogenesis and the translation of pathogenic biological activities into diagnostic and therapeutic applications.

Effect of postconditioning on mitochondrial dysfunction in experimental aortic cross-clamping

Background

Cross-clamping of the aorta during abdominal aortic aneurysm surgery induces muscle ischaemia with resultant morbidity. This study tested whether ischaemic postconditioning would decrease mitochondrial dysfunction in skeletal muscle by reducing oxidative stress.

Methods

Three groups (9 rats each) underwent surgery, including a control group without ischaemia and an ischaemia–reperfusion group that had 3 h ischaemia induced by aortic clamping and collateral vessel ligation, followed by 2 h of reperfusion. The third group had ischaemia for 3 h then underwent postconditioning comprising three short intervals of ischaemia–reperfusion at the onset of reperfusion. Activity of complexes I, II, III and IV of the mitochondrial respiratory chain was monitored in gastrocnemius muscle, along with oxidative stress measured by dihydroethidium (DHE) staining and antioxidant defence determined by measurement of glutathione levels.

Results

Ischaemia–reperfusion alone caused a significant reduction in maximal oxidative capacity (−31·8 per cent; P = 0·002), activity of complexes II, III and IV (−34·5 per cent; P = 0·007) and complex IV activity (−30·6 per cent; P = 0·039). It also increased reactive oxygen species (DHE staining increased to 223·1 per cent of control value; P = 0·027) and reduced antioxidant defence (glutathione level − 28·6 per cent; P = 0·039). Postconditioning counteracted these deleterious effects by increasing mitochondrial complex I, II, III and IV activities, restoring muscle DHE staining and preserving glutathione content.

Conclusion

Ischaemic postconditioning protects skeletal muscle mitochondria against ischaemia–reperfusion injury by reducing oxidative stress and preserving antioxidant defence in an experimental model. Mitochondrial protection to reduce reperfusion injury in clinical vascular surgery may be warranted.

Markers of inflammation in men with small abdominal aortic aneurysm

BACKGROUND

Markers of inflammation and fibrin turnover are elevated in individuals with a large (>55 mm) abdominal aortic aneurysm (AAA). Fibrin degradation generates D-dimer, known to possess multiple proinflammatory effects, and levels are elevated during early AAA development. This study characterized the plasma inflammatory response during early AAA pathogenesis to determine the effect of D-dimer levels.

METHODS

The study compared 75 men with a small AAA (range, 30-54 mm) with 90 age-, sex-, and race-matched controls. Plasma interleukin-6 (IL-6), complement C3, high-sensitivity C-reactive protein (hsCRP), fibrinogen, and D-dimer levels were measured.

RESULTS

Mean levels of fibrinogen (2.92 vs 2.59 g/L; P = .003), hsCRP (2.07 vs 1.29 ng/mL; P = .005), and D-dimer (346.7 vs 120.2 ng/mL; P < .001) were higher in men with a small AAA. These markers correlated with maximum aortic diameter determined by ultrasound imaging. On multivariate analysis, D-dimer levels were elevated in AAA individuals independent of smoking, cardiovascular disease (CVD), atherosclerotic risk factors, and inflammatory parameters. Fibrinogen and hsCRP levels remained elevated after adjustment for these covariates but lost significance when D-dimer was added to the model.

CONCLUSION

C-reactive protein and D-dimer levels are elevated during early AAA development. D-dimer levels are most tightly associated with AAA status, however, and may mediate the observed elevation in acute-phase reactants.

Plasma tissue plasminogen activator and abdominal aortic aneurysm presence: a systematic review and meta-analysis

BACKGROUND

To summarize the present evidence for an association between circulating tissue plasminogen activator (tPA) levels and abdominal aortic aneurysm (AAA) presence, we performed a systematic review and meta-analysis of case-control studies that compared plasma tPA levels between patients with AAA and subjects without AAA.

METHODS

MEDLINE was searched to identify all case-control studies that compared plasma tPA levels between patients with AAA and subjects without AAA. For each study, data regarding plasma tPA levels in both the AAA and control groups were used to generate standardized mean differences and 95% confidence intervals. Study-specific estimates were combined using inverse variance-weighted average of logarithmic standardized mean differences in both fixed- and random-effects models.

RESULTS

Our search identified five eligible case-control studies, including data on 234 patients with AAA and 459 subjects without AAA. Pooled analysis of the five studies demonstrated nonsignificantly higher plasma tPA levels in the AAA group than those in the control group in fixed-effect models (standardized mean differences = 0.07; 95% confidence interval = -0.09-0.24; p = 0.40). There was minimal study heterogeneity of results (p = 0.05) and no evidence of significant publication bias (p = 0.3272).

CONCLUSION

The results of our analysis suggest that plasma tPA levels may not be higher in patients with AAA than those in subjects without AAA. Higher plasma tPA levels may not be associated with AAA presence.

Haemostatic and fibrinolytic factors in men with a small abdominal aortic aneurysm

BACKGROUND

: The presence of an abdominal aortic aneurysm (AAA) independently predicts cardiovascular disease (CVD) and its complications. Levels of plasma markers of fibrin turnover are raised in men with a large AAA (at least 5.5 cm) and predict CVD risk in healthy subjects. This study examined fibrin turnover in men with a small AAA.

METHODS

: Seventy-five men with a small AAA (30-55 mm) were compared with 90 controls matched for age, sex and race. Haemostatic and fibrinolytic parameters were assessed.

RESULTS

: Men with a small AAA had higher mean levels of fibrinogen (2.92 versus 2.59 g/l; P = 0.019), thrombin-antithrombin (TAT) complex (4.57 versus 1.89 ng/ml; P < 0.001), prothrombin F1 + 2 (1.13 versus 0.82 ng/ml; P = 0.004) and D-dimer (346.7 versus 120.2 ng/ml; P < 0.001). All markers correlated with maximum aortic diameter determined by ultrasonography. On multivariable regression the association between presence of an AAA and fibrinogen, TAT complex, prothrombin F1 + 2 and D-dimer levels remained significant after adjustment for confounding influences.

CONCLUSION

: Fibrin turnover was increased in these men with a small AAA, independently of concomitant CVD, conventional risk factors and inflammatory markers. Enhanced fibrin turnover may contribute to the risk of cardiac complications in this group.

Preliminary results of a prospective randomized trial of restrictive versus standard fluid regime in elective open abdominal aortic aneurysm repair

BACKGROUND

Open abdominal aortic aneurysm (AAA) repair is associated with a significant morbidity (primarily respiratory and cardiac complications) and an overall mortality rate of 4% to 10%. We tested the hypothesis that perioperative fluid restriction would reduce complications and improve outcome after elective open AAA repair.

METHODS

In a prospective randomized control trial, patients undergoing elective open infra-renal AAA repair were randomized to a "standard" or "restricted" perioperative fluid administration group. Primary outcome measure was rate of major complications (MC) after AAA repair and secondary outcome measures included: Sequential Organ Failure Assessment Score; FiO2/PO2 ratio; Urinary Albumin/Creatinine Ratio; Length-of-stay in, intensive care unit, high dependency unit, in-hospital. This prospective Randomized Controlled Trial was registered in a publicly accessible database and has the following ID number ISRCTN27753612.

RESULTS

Overall 22 patients were randomized, 1 was excluded on a priori criteria, leaving standard group (11) and restricted group (10) for analysis. No significant difference was noted between groups in respect to age, gender, American Society Anesthesiology class, Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity scores, operation time, and operation blood loss. There were no in-hospital deaths and no 30-day mortality. The cumulative fluid balance on day 5 postoperative was for standard group, 8242 +/- 714 mL, compared with restricted group, 2570 +/- 977 mL, P < 0.01. MC were significantly reduced in the restricted group (n = 10), 1 MC, compared with standard group (n = 11), 14 MC, P < 0.024. Total and postoperative length-of-stay in-hospital was significantly reduced in the restricted group, 9 +/- 1 and 8 +/- 1 days, compared with standard group, 18 +/- 5 and 16 +/- 5 days, P < 0.01 and P < 0.025, respectively.

CONCLUSIONS

Serious complications are common after elective open AAA repair, and we have shown for the first time that a restricted perioperative fluid regimen can prevent MC and significantly reduce overall hospital stay.

Chronic obstructive pulmonary disease: a chronic systemic inflammatory disease

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation in both the airways causing airway obstruction and the lung tissues causing emphysema. The disease is induced by inhalation of noxious gasses and particulate matter resulting in a chronic persistent inflammatory response in the lung, and the extent of the inflammatory reaction correlates with the severity of the disease. This chronic inflammatory response in the lung is also associated with a significant systemic inflammatory response with downstream adverse clinical health effects. The systemic response in COPD is associated with mortality, specifically cardiovascular mortality. This review describes the nature of the systemic inflammatory response in COPD and the clinical manifestations associated with the systemic response, with a focus on the potential mechanisms for these adverse health effects.

Topology of the fibrinolytic system within the mural thrombus of human abdominal aortic aneurysms

Development and progression of acquired abdominal aortic aneurysms (AAAs) involve proteolytic activity. In the present study, we investigate the distribution of fibrinolytic system components within mural thrombi of human AAAs. 20 mural thrombi and the remaining AAA walls were dissected. The luminal, intermediate and abluminal thrombus layers, and media and adventitia were separately incubated in cell culture medium. Conditioned media were then analysed for plasminogen activators (PAs), plasminogen activator inhibitor-1 (PAI-1), free-plasmin, plasmin alpha(2)-antiplasmin complexes (PAPs) and D-dimers release. In parallel, PA and PAI-1 mRNA expression analysis was performed by RT-PCR. The study was completed by immunohistochemical localization of these components in AAA, ex vivo functional imaging using (99m)Tc-aprotinin as a ligand and measurement of PAP and D-dimer plasma levels. All fibrinolytic system components were present in each aneurysmal layer. However, the mural thrombus was the main source of active serine-protease release. Interestingly, the luminal layer of the thrombus released greater amounts of PAPs and D-dimers. This paralleled the preferential immunolocalization of plasminogen and PAs, and the (99m)Tc-aprotinin scintigraphic signal observed in the luminal pole of the thrombus. In contrast, mRNA expression analysis showed an exclusive synthesis of tPA and PAI-1 within the wall, whereas uPA mRNA was also expressed within the thrombus. Taken together, these results suggest that the increased plasma concentrations of PAPs and D-dimers found in AAA patients are related to mural thrombus proteolytic activity, thus explaining their known link with AAA progression. Components of the fibrinolytic system could also represent a target for functional imaging of thrombus activities in AAA.

Smoking and Aortic Diseases

Cigarette smoking is a major vascular risk factor and in this context, it is an independent risk factor for the development of aortic disease, especially the formation and growth of abdominal aortic aneurysms (AAA). Medline was searched up to January 31, 2007 for the relevant literature for this review of the mechanisms by which smoking causes aortic wall damage and its subsequent impact on the clinical manifestation of this process. Idiopathic AAAs and aortic dissection are considered, as well as other aortic diseases (eg, Takayasu, Kawasaki, Behcet and Buerger). There is evidence suggesting an abnormal homeostasis between proteolytic and antiproteolytic activity in the vascular wall during the development of AAAs, and these mechanisms can be influenced by smoking. Smoking cessation plays an important role in the management of aortic disease.