High circulating levels of cytokines (IL-6 and TNFalpha), adhesion molecules (VCAM-1 and ICAM-1) and selectins in patients with peripheral arterial disease at rest and after a treadmill test

Biomarkers of inflammation may be of use for identification of more severe peripheral arterial occlusive disease

Background:Atherosclerosis is a multifactorial disease with an inflammatory pathophysiological basis. Cytokines released during the atherosclerotic process induce production of C-reactive protein (CRP) in the liver, which is an important marker of inflammation.Objective:We tested whether inflammatory biomarkers were associated with deterioration of peripheral arterial occlusive disease (PAOD) in a population at high cardiovascular risk.Methods:1,330 subjects ≥30 years of age underwent clinical and laboratory examinations as part of a population-based study of the prevalence of diabetes. PAOD was defined as an ankle-brachial index (ABI) ≤0.90. After application of exclusion criteria, the sample comprised 1,038 subjects. Traditional risk factors, CRP and interleukin 6 (IL-6) were also compared across three ABI categories (≤0.70; 0.71-0.90; ≥0.90). Mean values for these variables were compared by presence/absence of DAOP (Student's t test) and by ABI categories (ANOVA). Poisson regression and logistic regression models were used to test for associations between risk factors and DAOP and between risk factors and the ABI categories. Pearson's linear correlation coefficients were calculated for the relationship between CRP and IL-6 levels.Results:Mean age was 56.8±12.9 years, 54% of the sample were women and the prevalence of DAOP was 21.0% (95%CI 18.4-24.1). Individuals with ABI ≤0.70 had higher concentrations of CRP-us (2.1 vs. 1.8) and of IL-6 (1.25 vs. 1.17). Concentrations of CRP and IL-6 were only correlated in patients with DAOP, (p=0.004).Conclusions:The finding that CRP and IL-6 levels were only elevated among people with advanced DAOP may suggest that these biomarkers have a role to play as indicators of more severe disease. Prospective studies are needed to test this hypothesis.

Sildenafil improves skeletal muscle oxygenation during exercise in men with intermittent claudication

Endothelial dysfunction caused by defective nitric oxide (NO) signaling plays a pivotal role in the pathogenesis of intermittent claudication (IC). In the present study, we evaluated the acute effects of sildenafil, a phosphodiesterase type 5 inhibitor that acts by prolonging NO-mediated cGMP signaling in vascular smooth muscle, on blood pressure (BP), skeletal muscle oxygenation, and walking tolerance in patients with IC. A randomized, double-blind, crossover study was conducted in which 12 men with stable IC received two consecutive doses of 50 mg of sildenafil or matching placebo and underwent a symptom-limited exercise test on the treadmill. Changes in gastrocnemius deoxy-hemoglobin by near-infrared spectroscopy estimated peripheral muscle O2delivery-to-utilization matching. Systolic BP was significantly lower during the sildenafil trial relative to placebo during supine rest (∼15 mmHg), submaximal exercise (∼14 mmHg), and throughout recovery (∼18 mmHg) ( P < 0.05). Diastolic BP was also lower after sildenafil during upright rest (∼6 mmHg) and during recovery from exercise (∼7 mmHg) ( P < 0.05). Gastrocnemius deoxygenation was consistently reduced during submaximal exercise (∼41%) and at peak exercise (∼34%) following sildenafil compared with placebo ( P < 0.05). However, pain-free walking time (placebo: 335 ± 42 s vs. sildenafil: 294 ± 35 s) and maximal walking time (placebo: 701 ± 58 s vs. sildenafil: 716 ± 62 s) did not differ between trials. Acute administration of sildenafil lowers BP and improves skeletal muscle oxygenation during exercise but does not enhance walking tolerance in patients with IC. Whether the beneficial effects of sildenafil on muscle oxygenation can be sustained over time and translated into positive clinical outcomes deserve further consideration in this patient population.

Association of monocyte tumor necrosis factor α expression and serum inflammatory biomarkers with walking impairment in peripheral artery disease

OBJECTIVE

Inflammation contributes to the development of peripheral artery disease (PAD) and may contribute to intermittent claudication by adversely affecting vascular and skeletal muscle function. We explored the association of inflammation to maximal walking time (MWT) in patients with claudication.

METHODS

Circulating inflammatory biomarkers, including tumor necrosis factor α (TNF-α), C-reactive protein (CRP), interleukin-6 (IL-6), and soluble intercellular adhesion molecule 1 (sICAM), were measured in 75 subjects with intermittent claudication as well as in 43 healthy subjects. Real-time polymerase chain reaction was used to quantify mRNA expression of TNF-α, IL-6, interferon-γ, and CD36 from peripheral blood monocytes. Treadmill testing was performed in PAD subjects to assess MWT.

RESULTS

Compared with healthy subjects, PAD subjects had higher levels of circulating TNF-α (P < .0001), CRP (P = .003), sICAM (P < .0001), and IL-6 (P < .0001). Expression of both IL-6 (P = .024) and CD36 (P = .018) was greater in PAD subjects than in healthy subjects. Among subjects with PAD, higher gene expression of TNF-α was associated inversely with MWT (P = .01). MWT was also associated inversely with greater levels of circulating TNF-α (P = .028), CRP (P = .024), IL-6 (P = .03), and sICAM (P = .018).

CONCLUSIONS

Systemic inflammation, as indicated by TNF-α inflammatory gene expression in peripheral blood monocytes and by circulating biomarker levels, is associated with impairment in walking time in patients with PAD and intermittent claudication.

Plasma and serum L-selectin and clinical and subclinical cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis (MESA)

L-selectin has been suggested to play a role in atherosclerosis. Previous studies on cardiovascular disease (CVD) and serum or plasma L-selectin are inconsistent. The association of serum L-selectin (sL-selectin) with carotid intima-media thickness, coronary artery calcium, ankle-brachial index (subclinical CVD), and incident CVD was assessed in 2403 participants in the Multiethnic Study of Atherosclerosis. Regression analysis and the Tobit model were used to study subclinical disease; Cox proportional hazards regression, for incident CVD. Mean age was 63 ± 10 years and 47% were male. Mean sL-selectin was significantly different across ethnicities. Within each race/ethnicity, sL-selectin was associated with age and sex; among non-Hispanic whites and African Americans, it was associated with smoking status and current alcohol use. sL-selectin levels did not predict subclinical or clinical CVD after correction for multiple comparisons. Conditional logistic regression models were used to study the association of plasma L-selectin and CVD in 154 incident CVD cases, and 306 age-, sex-, and ethnicity-matched control subjects. The median follow-up time was 8.5 years. L-selectin levels in plasma were significantly lower than in serum and the overall concordance was low. Plasma levels were not associated with CVD. In conclusion, in this large, multiethnic population, soluble L-selectin levels did not predict clinical or subclinical CVD.

Greater endothelial apoptosis and oxidative stress in patients with peripheral artery disease

We compared apoptosis, cellular oxidative stress, and inflammation of cultured endothelial cells treated with sera from 156 subjects with peripheral artery disease (PAD) and 16 healthy control subjects. Furthermore, we compared circulating inflammatory, antioxidant capacity, and vascular biomarkers between the two groups. The PAD group had a 164% higher value for endothelial cell apoptosis (P < 0.001) and a 62% higher value for endothelial cellular reactive oxygen species production (P < 0.001) than the control group. Furthermore, the PAD group had lower systemic antioxidant capacity measured by hydroxyl radical antioxidant capacity activity (P < 0.001), higher inflammatory and vascular measures of high-sensitivity C-reactive protein (P < 0.001), interleukin-8 (P < 0.001), serum amyloid A (P < 0.001), vascular cell adhesion molecule-1 (P < 0.001), adiponectin (P < 0.001), apolipoprotein B (P = 0.013), apolipoprotein CIII (P = 0.035), lower vascular endothelial growth factor-A (P < 0.001), and hepatocyte growth factor (P < 0.001) than the control group. Subjects with PAD have greater endothelial apoptosis and oxidative stress than control subjects with low burden of comorbid conditions and cardiovascular risk factors. Furthermore, subjects with PAD have lower systemic antioxidant capacity and angiogenic measures and higher circulating inflammatory parameters.

Gender and racial differences in endothelial oxidative stress and inflammation in patients with symptomatic peripheral artery disease

BACKGROUND

We compared (1) cellular reactive oxygen species (ROS) production, inflammation, and apoptosis of cultured endothelial cells treated with sera and (2) circulating inflammatory measures, antioxidant capacity, vascular biomarkers, and calf muscle hemoglobin oxygen saturation (StO2) in men and women with peripheral artery disease (PAD). A secondary aim was to compare exercise performance and daily ambulatory activity between men and women. We hypothesized that women would have more impaired endothelial cellular ROS, inflammation, and apoptosis than men as well as worse systemic inflammation, antioxidant capacity, vascular biomarkers, calf muscle StO2, exercise performance, and daily ambulatory activity.

METHODS

The 148 symptomatic men and women with PAD were characterized on the endothelial effects of circulating factors present in the sera by a cell culture-based bioassay on primary human arterial endothelial cells. Patients were further evaluated by circulating inflammatory and vascular biomarkers, physical examination and medical history, exercise performance, and calf muscle StO2 during exercise, and ambulatory activity was monitored during 1 week.

RESULTS

Cellular ROS production was higher in African American women than in men (P = .021), but there was no gender difference in white individuals (P = .537). Men and women were not significantly different on endothelial cell apoptosis (P = .833) and nuclear factor κB activity (P = .465). For circulating factors, additional gender differences were found when comparisons were made within each race. In African Americans, women had higher intercellular adhesion molecule 1 (P = .022) and leptin (P < .001); whereas in white individuals, women had higher matrix metallopeptidase 9 (P = .047), higher vascular cell adhesion molecule 1 (P = .047), and lower hepatocyte growth factor (P = .046). Overall, women had higher apolipoprotein CIII (P = .035), lower pain-free distance (P = .048) and total distance (P < .001) during the 6-minute walk test, shorter time for calf muscle StO2 to reach the minimum value during exercise (P = .027), and slower average cadence (P = .004) during daily ambulation.

CONCLUSIONS

African American women with symptomatic PAD have a heightened oxidative status, likely resulting in increased endothelial oxidative stress, compared with men. Furthermore, women exhibit a more pronounced proinflammatory profile of circulating biomarkers as well as more limited peripheral microcirculation, exercise performance, and ambulatory activity than men do. The clinical significance is that women with symptomatic PAD are in greater need than men of clinical intervention to improve oxidative stress, inflammation, and microcirculation, which may in turn have a favorable impact on their lower exercise performance and daily activity.

Impaired vascular endothelial growth factor A and inflammation in patients with peripheral artery disease

We compared apoptosis, cellular oxidative stress, and inflammation of cultured endothelial cells treated with sera from 130 patients with peripheral artery disease (PAD) and a control group of 36 patients with high burden of comorbid conditions and cardiovascular risk factors. Second, we compared circulating inflammatory, antioxidant capacity, and vascular biomarkers between the groups. The groups were not significantly different (P > .05) on apoptosis, hydrogen peroxide, hydroxyl radical antioxidant capacity, and nuclear factor κ-light-chain enhancer of activated B cells. Circulating tumor necrosis factor α (TNF-α; P = .016) and interleukin 8 (IL-8; P = .006) were higher in the PAD group, whereas vascular endothelial growth factor A (VEGF-A; P = .023) was lower. The PAD does not impair the endothelium beyond that which already occurs from comorbid conditions and cardiovascular risk factors in patients with claudication. However, patients with PAD have lower circulating VEGF-A than the control group and higher circulating inflammatory parameters of TNF-α and IL-8.

NOX2 up-regulation is associated with artery dysfunction in patients with peripheral artery disease

OBJECTIVE

Oxidative stress seems to play a role in impairing flow-mediated dilation (FMD) in patients with peripheral artery disease (PAD) but the underlying mechanism is still undefined. We evaluated whether NOX2, the catalytic core of NADPH oxidase, the most important producer of reactive oxidant species (ROS), is implicated in impairing FMD.

METHODS

We measured FMD, urinary isoprostanes, a marker of oxidative stress, nitric oxide generation by serum levels of nitrite/nitrate (NOx), and serum levels of soluble NOX2-derived peptide (sNOX2-dp), a marker of NOX2 activation, in 50 PAD patients and 50 controls. Also, we performed an interventional cross-over study to assess if propionyl-L-carnitine (PLC) (6g/day), vs. placebo, was able to affect FMD via an oxidative stress-mediated mechanism.

RESULTS

Compared to controls, patients with PAD had enhanced sNOX2-dp and isoprostanes and reduced NOx and FMD. Multiple linear regression analysis showed that FMD was independently associated with sNOX2-dp. After PLC infusion FMD increased while sNOX2-dp and isoprostanes significantly decreased; no changes were observed after placebo. In vitro study by incubating platelets or white cells with PLC demonstrated a significant inhibition of p47(phox) translocation on cellular surface and ROS generated by NOX2 activation.

CONCLUSION

This study suggests that in PAD patients ROS generated by NOX2 contribute to reduce FMD and that the administration of an antioxidant is able to improve arterial dilatation via NOX2 inhibition.

Higher serum levels of soluble intracellular cell adhesion molecule-1 and soluble vascular cell adhesion molecule predict peripheral artery disease in haemodialysis patients

AIM

Serum levels of soluble intracellular cell adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM) and monocyte chemotactic protein 1 (MCP-1), are elevated in patients with peripheral artery disease (PAD). However, the levels of these cell adhesion molecules in patients undergoing haemodialysis (HD) are unclear.

METHOD

A total of 112 HD patients were included and PAD was diagnosed using the ankle-brachial index and Doppler ultrasound. Serum levels of sICAM-1, sVCAM-1 and MCP-1 were assayed using enzyme linked immunosorbent assay.

RESULTS

Out of 106 HD patients, 31 (27.7%) were diagnosed with PAD. After adjusting for risk factors, higher serum levels of sVCAM-1 and sICAM-1 were associated with PAD in HD patients, with an odds ratio of 5.3 (95% CI 3.3-65.5) and 2.7 (95% CI 1.2-21.8) respectively. Using sVCAM-1 and sICAM-1 for diagnosis of PAD in HD patients, sVCAM-1 had a sensitivity of 72.4% and specificity of 62.3% for sVCAM-1 and sICAM-1 had a sensitivity of 89.3% and a specificity of 40%. MCP-1 was not associated with PAD in HD patients. In addition, the fistula of HD patients with PAD had a lower A-V access flow.

CONCLUSION

sVCAM-1 and sICAM-1 was associated with higher risk of PAD in HD patients. Moreover, HD patients with PAD had a lower blood flow and lower A-V access flow. Our results showed that sVCAM-1 and sICAM-1 may be used as screening markers for PAD in HD patients.

IL-6-174 G > C and MMP-9-1562 C > T polymorphisms are associated with increased risk of deep vein thrombosis in cancer patients

BACKGROUND

A growing body of evidence shows an increased risk of deep vein thrombosis (DVT) among cancer patients. Novel markers are needed to identify patients prone to develop DVT. The aim of the present study was to determine whether IL-6-174 G > C and MMP-9-1562 C > T polymorphisms may influence the development of DVT in cancer patients.

METHODS

Polymorphisms of IL-6 and MMP-9 were analyzed in 320 DNA samples from cancer patients (DVT+ and DVT-) and in 215 healthy donors. IL-6 and MMP-9 plasma levels were also measured by ELISA.

RESULTS

Distribution of -174 IL-6 genotype and -1562 MMP-9 were similar between healthy controls and DVT- cancer cases (OR = 0.98 and 1.04, respectively). Different results were obtained by compared healthy controls with DVT+ cancer patients. -174 IL-6 GG polymorphism was associated to DVT (OR = 2.07; 95% CI: 1.30-3.30), as well as -1562 MMP-9 CC polymorphism (OR = 2.60; 95% CI: 1.48-4.57).

CONCLUSION

The results of the present study support a model in which the GG and CC genotypes, respectively for IL-6-174 G > C and MMP-9-1562 C > T polymorphisms, are associated with a risk of DVT in cancer patients by inducing the release of IL-6 with subsequent increment of MMP-9. Overall, these findings may contribute to the management of DVT in cancer patients.

Nonesterified fatty acids modify inflammatory response and eicosanoid biosynthesis in bovine endothelial cells

Intense lipid mobilization during the transition period in dairy cows is associated with increased disease susceptibility. The potential impact of altered plasma nonesterified fatty acids (NEFA) concentrations and composition on host inflammatory responses that may contribute to disease incidence and severity are not known. The objective of this study was to evaluate if increased NEFA concentrations could modify vascular inflammatory responses in vitro by changing the expression of important inflammatory mediators that are important in the pathogenesis of infectious diseases of transition cows such as mastitis and metritis. Bovine aortic endothelial cells (BAEC) were cultured with different concentrations of a NEFA mixture that reflected the plasma NEFA composition during different stages of lactation. The expression of cytokines, adhesion molecules, and eicosanoids were measured to assess changes in BAEC inflammatory phenotype. Addition of NEFA mixtures altered the fatty acid profile of BAEC by increasing the concentration of stearic acid (C18:0) and decreasing the content of arachidonic acid (C20:4n6c) and other long-chain polyunsaturated fatty acids in the phospholipid fraction. A significant increase also occurred in mRNA expression of cytokine and adhesion molecules that are associated with increased inflammatory responses during the transition period. Expression of cyclooxygenase 2, an important enzyme associated with eicosanoid biosynthesis, was increased in a NEFA concentration-dependent manner. The production of linoleic acid-derived eicosanoids 9- and 13-hydroxyoctadecadienoic acids also was increased significantly after treatment with NEFA mixtures. This research described for the first time specific changes in vascular inflammatory response during in vitro exposure to NEFA mixtures that mimic the composition and concentration found in cows during the transition period. These findings could explain, in part, alterations in inflammatory responses observed during intense lipid mobilization stages such as in the transition period of dairy cows. Future studies should analyze specific mechanisms by which high NEFA concentrations induce a vascular proinflammatory phenotype including the effect of 9 and 13-hydroxyoctadecadienoic acids and other lipid mediators.

Systemic inflammation in peripheral arterial disease with or without coexistent chronic obstructive pulmonary disease: analysis of selected markers

INTRODUCTION

Low-grade systemic inflammation plays an important role in the pathogenesis and natural history of chronic obstructive pulmonary disease (COPD) and peripheral arterial disease (PAD). The aim of the study was to analyze plasma concentrations of selected markers of inflammation in patients suffering from PAD with or without coexistent COPD.

MATERIAL AND METHODS

Thirty patients (6 women) with advanced PAD (at least IIb stage according to Fontaine scale) hospitalized due to critical limb ischemia were examined. In all patients spirometry was performed to confirm or exclude COPD. Plasma concentration of IL-6, IL-8 and TNF-α was measured using ELISA method. Statistical analysis was performed according to COPD status and according to smoking status independently.

RESULTS

In the whole group of patients with PAD, COPD was recognized in 14 cases (for the first time in 10 cases). All patients were smokers (46.7% current, 53.3% ex-smokers). We found a significant correlation between FEV1%N (percent of norm of first second expiratory volume) and the number of years of smoking (r = -0.39; p < 0.05). We found similar concentrations of IL-6 (2.54 pg/ml vs. 2.31 pg/ml), IL-8 (8.55 pg/ml vs. 8.14 pg/ml, TNF-α (0.72 pg/ml vs. 1.75 pg/ml) in the COPD(+) group in comparison to the COPD(-) group (differences were not significant). We observed significant positive correlations (p < 0.05) between concentrations of measured markers and significant negative correlations between pain free walking distance and these markers.

CONCLUSIONS

Our study confirmed coexistence of PAD with COPD. The character of inflammation is similar in these smoking-related diseases.

Toll-like receptors in ischaemia and its potential role in the pathophysiology of muscle damage in critical limb ischaemia

Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.

Polymorphisms in the ICAM1 gene predict circulating soluble intercellular adhesion molecule-1(sICAM-1)

OBJECTIVE

Polymorphisms within the ICAM1 structural gene have been shown to influence circulating levels of soluble intercellular adhesion molecule-1 (sICAM-1) but their relation to atherosclerosis has not been clearly established. We sought to determine whether ICAM1 SNPs are associated with circulating sICAM-1 concentration, coronary artery calcium (CAC), and common and internal carotid intima medial thickness (IMT).

METHODS AND RESULTS

3550 black and white Coronary Artery Risk Development in Young Adults (CARDIA) Study subjects who participated in the year 15 and/or 20 examinations and were part of the Young Adult Longitudinal Study of Antioxidants (YALTA) ancillary study were included in this analysis. In whites, rs5498 was significantly associated with sICAM-1 (p<0.001) and each G-allele of rs5498 was associated with 5% higher sICAM-1 concentration. In blacks, each C-allele of rs5490 was associated with 6% higher sICAM-1 level; this SNP was in strong linkage disequilibrium with rs5491, a functional variant. Subclinical measurements of atherosclerosis in either year 15 or year 20 were not significantly related to ICAM1 SNPs.

CONCLUSIONS

In CARDIA, ICAM1 DNA segment variants were associated with sICAM-1 protein level including the novel finding that levels differ by the functional variant rs5491. However, ICAM1 SNPs were not strongly related to either IMT or CAC. Our findings in CARDIA suggest that ICAM1 variants are not major early contributors to subclinical atherosclerosis.

IκBα degradation is necessary for skeletal muscle atrophy associated with contractile claudication

The arterial blockage in patients with peripheral arterial disease (PAD) restricts oxygen delivery to skeletal muscles distal to the blockage. In advanced-stage PAD patients, this creates a chronic ischemic condition in the affected muscles. However, in the majority of PAD patients, the muscles distal to the blockage only become ischemic during physical activity when the oxygen demands of these muscles are increased. Therefore, the skeletal muscle of most PAD patients undergoes repeated cycles of low-grade ischemia-reperfusion each time the patient is active and then rests. This has been speculated to contribute to the biochemical and morphological myopathies observed in PAD patients. The current study aimed to determine, using a rodent model, whether repeated hind limb muscle contractions during blood flow restriction to the hind limb muscles increases NF-κB activity. We, subsequently, determined whether an increase in NF-κB activity during this condition is required for the increased transcription of specific atrophy-related genes and muscle fiber atrophy. We found that hind limb muscle contractions during blood flow restriction to the limb increased NF-κB activity, the transcription of specific atrophy-related genes, and caused a 35% decrease in muscle fiber cross-sectional area. We further found that inhibition of NF-κB activity, via gene transfer of a dominant-negative inhibitor of κBα (d.n. IκBα), prevented the increase in atrophy gene expression and muscle fiber atrophy. These findings demonstrate that when blood flow to skeletal muscle is restricted, repeated cycles of muscle contraction can cause muscle fiber atrophy that requires NF-κB-IκBα signaling.

Models of accelerated sarcopenia: critical pieces for solving the puzzle of age-related muscle atrophy

Sarcopenia, the age-related loss of skeletal muscle mass, is a significant public health concern that continues to grow in relevance as the population ages. Certain conditions have the strong potential to coincide with sarcopenia to accelerate the progression of muscle atrophy in older adults. Among these conditions are co-morbid diseases common to older individuals such as cancer, kidney disease, diabetes, and peripheral artery disease. Furthermore, behaviors such as poor nutrition and physical inactivity are well-known to contribute to sarcopenia development. However, we argue that these behaviors are not inherent to the development of sarcopenia but rather accelerate its progression. In the present review, we discuss how these factors affect systemic and cellular mechanisms that contribute to skeletal muscle atrophy. In addition, we describe gaps in the literature concerning the role of these factors in accelerating sarcopenia progression. Elucidating biochemical pathways related to accelerated muscle atrophy may allow for improved discovery of therapeutic treatments related to sarcopenia.

Propionyl l-carnitine: intermittent claudication and peripheral arterial disease

Peripheral arterial disease (PAD) is a clinical manifestation of underlying aorto-iliac and leg atherosclerosis that is characterized by different stages of stenosis and obstruction. It affects approximately 12% of the adult population and about 20% of people over the age of 70 years, and is associated with increased cardiovascular (CV) and cerebrovascular morbidity. Intermittent claudication (IC) is the major symptom of PAD; it is defined as cramping leg pain (in the buttock, thigh, or calf) while/after clim bing one or two flights of stairs, or during walking. The goals of IC management are to: slow the progression of local and systemic atherosclerosis, prevent major fatal and nonfatal CV events (myocardial infarction and stroke), improve walking capacity, prevent and reduce resting pain and cutaneous lesions. Propionyl L-carnitine is an acyl derivative of levocarnitine (L-carnitine) and is indicated for patients with peripheral arterial occlusive disease. It corrects secondary muscle carnitine deficiency in patients with PAD, significantly improving the walking capacity; it is a free radical that produces positive effects on endothelial function; it protects from oxidative stress; and it enhances most measures of quality of life. The recent Trans-Atlantic Inter-Society Consensus II update recommends the use of propionyl L-carnitine in combination with physical training to improve the symptoms associated with PAD.

Novel markers of peripheral arterial disease

Peripheral arterial disease (PAD), a relatively common manifestation of atherosclerotic vascular disease, is associated with significant morbidity and mortality. Although conventional risk factors contribute to the onset and progression of PAD, the role of 'novel' biomarkers in pathways of inflammation, thrombosis, lipoprotein metabolism, and oxidative stress in determining susceptibility to PAD is being increasingly recognized. Validation of novel risk factors for PAD may allow earlier detection, an improved understanding of disease etiology and progression, and the development of new therapies. In this review, we discuss available evidence for associations between novel circulating markers and several aspects of PAD including disease susceptibility, progression, functional limitation, and adverse outcomes.

A helicopter flight does not induce significant changes in systemic biomarker profiles

Whole-body vibration and noise are inherent characteristics of helicopter operations. The helicopter pilot is affected by vibration from both low-frequency noise and mechanical vibration sources. The way this energy is transmitted to different tissues and organs depends on intensity, frequency and resonance phenomena within the body. Whole-body vibration is known to affect the muscular and skeletal system in the lower part of the spine, but less is known about the response at the cellular level to this stimulation. In some studies, chronic pathological changes have been described in different types of tissue in people exposed to low-frequency noise and vibration. The aim of the present study was to investigate possible cellular reactions to acute exposure to low-frequency noise and vibration in a helicopter. Thirteen healthy males aged 38 (18-69) years were subjected to a 3.5 h helicopter flight in a Westland Sea King Rescue helicopter. Blood tests taken before and after the flight were analysed for more than 40 parameters, including acute phase reactants, markers of leucocyte and platelet activation, complement and hemostasis markers, as well as a broad panel of cytokines, chemokines, growth factors and cell adhesion molecules. The subjects served as their own controls. With the exception of an increase in vascular cell adhesion molecule-1 (VCAM-1) during the flight, no statistically significant changes in the biomarkers were found after controlling for diurnal variation in the control blood tests, which were observed independently of the helicopter flight. In conclusion, one helicopter flight does not induce measurable changes in systemic biomarkers.

The association of acute exercise-induced ischaemia with systemic vasodilator function in patients with peripheral arterial disease

Abstract

Patients with peripheral arterial disease (PAD) frequently experience ischaemic attacks of the affected tissues during exercise. The present study assesses the association of transient exercise-induced leg ischaemia with vasodilator function of the clinically unaffected brachial artery over the course of 4 hours. Thirty male patients with symptomatic PAD and 14 age- and sex-matched healthy controls were included in the study. They performed a treadmill exercise until intolerable exercise-induced ischaemic pain occurred in the affected lower extremity, or for at most 10 min. Flow-mediated dilation (FMD) of the brachial artery was measured at baseline, 30 minutes, 2 hours and 4 hours after exercise. Baseline FMD values were significantly diminished in patients (7.03 ± 1.99% vs 8.22 ± 1.60% in controls, p = 0.009). A significant decrease in FMD was observed in patients after exercise (at 30 minutes: 3.92 ± 1.78% vs 7.03 ± 1.99% at baseline, p < 0.001; at 2 hours: 6.36 ± 2.12% vs 7.03 ± 1.99% at baseline, p = 0.005), followed by a gradual return to its baseline value, whereas FMD in controls non-significantly increased after exercise. The difference in the pattern of FMD change over time between patients and controls was significant ( p < 0.001). This study shows that in PAD patients ischaemia during intermittent claudication is related to a transitory functional deterioration of the distant arteries. This indicates the harmful systemic effects of repeated ischaemic attacks during exercise and might explain the generalized and advanced nature of atherosclerotic disease in PAD patients.

Cross-sectional relations of multiple inflammatory biomarkers to peripheral arterial disease: The Framingham Offspring Study

BACKGROUND

Emerging evidence suggests that different inflammatory biomarkers operate through distinct biologic mechanisms. We hypothesized that the relation to peripheral arterial disease (PAD) varies for individual markers.

METHODS

In a community-based sample we measured 12 biomarkers including plasma CD40 ligand, fibrinogen, lipoprotein-associated phospholipase-A2 mass and activity, osteoprotegerin, P-selectin, and tumor necrosis factor receptor 2 (TNFR2); and serum C-reactive protein, intracellular adhesion molecule-1, interleukin-6, monocyte chemoattractant protein-1, and myeloperoxidase in Framingham Offspring Study participants (n=2800, 53% women, mean age 61 years). We examined the cross-sectional relation of the biomarker panel to PAD using (1) a global test of significance to determine whether at least one of 12 biomarkers was related to PAD using the TEST statement in the LOGISTIC procedure in SAS and (2) stepwise multivariable logistic regression with forward selection of markers with separate models for (1) ankle-brachial index (ABI) category (<0.9, 0.9-1.0, >1.0) and (2) presence of clinical PAD (intermittent claudication or lower extremity revascularization).

RESULTS

The group of inflammatory biomarkers were significantly related to both ABI and clinical PAD (p=0.01 and p=0.02, respectively, multi-marker adjusted global significance test). Multivariable forward elimination regression retained interleukin-6 and TNFR2 as significantly associated with PAD. For one standard deviation change in interleukin-6 and TNFR2 concentrations, there was a 1.21 (p=0.005) and 1.19 (p=0.009) increased odds of a change in ABI level respectively. Similar results were observed for clinical PAD.

CONCLUSION

Interleukin-6 and TNFR2 were significantly associated with PAD independent of established risk factors and each other, suggesting that each marker represents a distinct biologic pathway.

Endothelial dysfunction: a key to the pathophysiology and natural history of peripheral arterial disease?

Dysfunctional endothelium plays a crucial role in all stages of atherosclerosis and thus the accurate assessment of this organ is a valuable tool, especially if such assessments are clinically relevant. In peripheral arterial disease (PAD), which affects about 27 million of individuals in Europe and North America, increased plasma markers of endothelial dysfunction and reduced endothelium-mediated vasoreactivity, are associated with both the severity and the extent of atherosclerosis in the arteries of the lower limbs, is exacerbated by acute exercise, may help identify subjects with subclinical coronary artery disease, and portends a worse outcome. As a result, endothelial dysfunction is a promising target for therapeutic interventions in PAD. Large clinical trials are needed to verify whether affected individuals with depressed endothelial function benefit from specific treatments.

ICAM1 and VCAM1 polymorphisms, coronary artery calcium, and circulating levels of soluble ICAM-1: the multi-ethnic study of atherosclerosis (MESA)

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) may be important contributors to the development and progression of atherosclerosis. Using a stratified random sample of 2880 participants of the Multi-Ethnic Study of Atherosclerosis we investigated the relationship of 12 ICAM1 and 17 VCAM1 SNPs and coronary artery calcium (CAC) and ICAM1 SNPs and circulating levels of soluble ICAM-1 (sICAM-1). There were no ICAM1 or VCAM1 SNPs significantly associated with CAC in any of the four race/ethnic groups. In a subset of 1451 subjects with sICAM-1 measurements, we observed a significant association with rs5491 in all four race/ethnic groups corroborating previous research that has shown that the T-allele of rs5491 interferes with the monoclonal antibody used to measure sICAM-1 in this study. After excluding all rs5491 T-allele carriers, several ICAM1 SNPs were significantly associated with sICAM-1 levels; rs5496 in African Americans, rs5498 and rs3093030 in European Americans, and rs1799969 in Hispanics. Our results identified ICAM1 polymorphisms that were significantly associated with sICAM-1 level but not CAC, a subclinical marker of atherosclerosis.

The effects of exercise stress testing on soluble E-selectin, von Willebrand factor, and circulating endothelial cells as indices of endothelial damage/dysfunction

BACKGROUND

The quantification of circulating endothelial cells (CECs) in whole blood is an increasingly recognized index of endothelial damage/dysfunction. Abnormal CECs have been linked to the severity of coronary artery disease (CAD).

OBJECTIVE

We assessed the relationship of CECs to other markers of endothelial dysfunction (von Willebrand factor (vWF) and soluble E-selectin (sEsel)) during exercise stress testing (EST) in a cohort of patients with suspected CAD.

METHODS

We studied a cohort of patients referred to our chest pain clinic with a history of exertional chest pain. Treadmill EST was performed, using a full Bruce exercise protocol. Blood for CECs (immunobead method), vWF and sEsel (both ELISA) were collected immediately before (pre-exercise), immediately following exercise, and at 30 minutes post-EST.

RESULTS

We studied 31 patients (84% male; mean (SD) age 58.4 (9.8) years). Of the entire cohort, 14 patients (45.2%) had a positive EST. Exercise led to significant increases in levels of CECs, sEsel, vWF, white blood cells (WBC), heart rate, mean and systolic blood pressure compared with base-line (all P < 0.05). There was a significant correlation between the change (delta (immediate post-pre-exercise)) in CECs and delta vWF (r = 0.45; 95% CI 0.11-0.69: P = 0.01) and delta sEsel (r = 0.41; 0.05-0.7: P = 0.02), as well as between delta vWF and delta sEsel (r = 0.55; 0.25-0.76: P = 0.001). Neither absolute nor delta CEC counts were predictive of exercise work-load/functional capacity, nor the presence of positive EST results.

CONCLUSION

EST led to a significant increase in endothelial markers (CECs, vWF, and sEsel) compared with base-line levels. The rise in CECs correlated with the increases in other endothelial markers, but was not related to the either exercise workload/capacity or to the presence of a positive EST.

Periodontitis may increase the risk of peripheral arterial disease

OBJECTIVES

The aim of this case control study was to evaluate whether periodontitis was associated with peripheral arterial disease (PAD).

SUBJECTS AND METHODS

Twenty-five patients diagnosed with aorto-iliac and/or femoro-popliteal occlusive disease and thirty-two generally healthy control subjects were enrolled in this study. Polymerase chain reaction (PCR) was used to identify Porphyromonas gingivalis, Treponema denticola, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Cytomegalovirus (CMV), Chlamydia pneumoniae, and Helicobacter pylori in tissue specimens taken from the anastomotic site of distal bypasses. Periodontal status was evaluated; serum IgG titres against the four listed bacteria were measured.

RESULTS

Periodontopathic bacteria were detected in 13/25 (52%) atherosclerotic specimens. CMV or C. pneumoniae was detected in 1/25 (4%) specimens; H. pylori was not detected from any of these specimens. Fontaine grade III or IV patients showed higher detection frequency of P. gingivalis than Fontaine grade II patients (57.1% vs 22.2%, P=0.09). After adjusting for age, gender, diabetes and smoking, periodontitis increased 5-fold the risk of having PAD (OR 5.45). There were preliminary indications that periodontitis was associated with increased serum IL-6 and TNF-alpha concentrations.

CONCLUSIONS

This study suggests that periodontitis may be associated with an increased risk of PAD. This association could result from the increased concentration of serum inflammatory cytokines in those with periodontitis.

A rational connection of inflammation with peripheral arterial disease

Peripheral arterial disease (PAD) includes a wide range of manifestations in the lower limb, from asymptomatic to symptomatic disease ranging from intermittent claudication to critical limb ischemia, with ulcers, rest pain, or gangrene. It is manifestation of generalized atherosclerosis and this is clearly shown by the high prevalence of coexistence coronary and cerebral arterial disease in these patients. The cumulative findings on molecular and cellular biology have dramatically changed our concept of atherosclerotic disease. Recently, it has become clear that inflammation is fundamental to the process of atherosclerosis. Although the relation between inflammation and PAD is not well characterized, the emerging data demonstrated that PAD is a common manifestation of atherosclerosis that is associated with a systemic inflammation. The most important risk factors for PAD are similar to those of atherosclerotic disease elsewhere: age, male sex, diabetes mellitus, smoking, hypertension, hyperlipidemia, and hereditary factors. Serum levels of inflammatory markers, especially after exercise, have been found to be higher in patients with PAD than in controls, and associated with prognosis as well as restenosis in patients with PAD after revascularization. In the general United States adult population, inflammation is independently associated with PAD in a cross-sectional, nationally large representative sample. All of those evidences indicate that PAD is one aspect of atherosclerosis, a disease rationally connects with inflammation, which may further change our preventive and therapeutic strategies.

Fish oil induced increase in walking distance, but not ankle brachial pressure index, in peripheral arterial disease is dependent on both body mass index and inflammatory genotype

Peripheral arterial disease (PAD) is an atherosclerotic disease. Evidence suggests that atherosclerosis is an inflammatory condition and long chain n-3 fatty acids, found in oily fish and fish oils, have been shown to reduce inflammation. Genetic and lifestyle factors such as body mass index (BMI) also influence inflammation. In this study we have examined the effect of fish oil in patients with claudication secondary to PAD. Fish oil supplementation, providing 1g EPA and 0.7 g DHA per day for 12 weeks, increased walking distance on a treadmill set at 3.2 km/h with a 7% incline. Walking distance to first pain increased from 76.2+/-8.5 m before fish oil to 140.6+/-25.5 m after fish oil (mean+/-SEM, p=0.004) and total distance walked increased from 160.0+/-21.5 m before fish oil to 242.1+/-34.5 m after fish oil (p=0.002). Fish oil supplementation also improved ankle brachial pressure index (ABPI) from 0.599+/-0.017 before fish oil to 0.776+/-0.030 after fish oil (p<0.001). The increase in walking distance was dependent on both BMI and genotype for single nucleotide polymorphisms in the genes encoding the pro-inflammatory cytokines tumour necrosis factor-alpha and interleukin (IL)-1beta and the anti-inflammatory cytokine IL-10 (detected using amplification refractory mutation system polymerase chain reaction). Neither BMI nor any of the genotypes examined affected the ability of fish oil to increase ABPI. The mechanisms by which fish oil affects walking distance and ABPI do not appear to be the same.

Effects of progressive and maximal exercise on plasma levels of adhesion molecules in athletes with sickle cell trait with or without α-thalassemia

The aim of the study was to examine the effects of exercise on soluble vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) in sickle cell trait (SCT) athletes with or without α-thalassemia. Six athletes with SCT, seven athletes with both SCT and α-thalassemia (SCTAT), and seven control athletes (Cont) performed an incremental and maximal test on cycloergometer. Levels of sICAM-1 and sVCAM-1 were assessed at rest, immediately after the end of exercise, and 1, 2, and 24 h after exercise. Although Cont and SCTAT groups exhibited similar basal plasma levels of inflammatory and adhesion molecules, the SCT group had higher sVCAM-1 basal concentrations. Incremental exercise resulted in a significant increase of sVCAM-1 in all subjects, which remained elevated only in the SCT group during the recovery period. In conclusion, as sVCAM-1 increased with exercise and during the recovery period, our findings support the concept that SCT athletes might be at risk for microcirculatory disturbances and adhesive phenomena developing at rest and several hours after exercise. α-Thalassemia might be considered protective among exercising SCT subjects.

Cellular adhesion molecules and peripheral arterial disease

Cellular adhesion molecules (CAMs), by mediating the recruitment of circulating leukocytes to the blood vessel wall and their subsequent migration into the subendothelial spaces, play a crucial role in all stages of atherosclerosis. Soluble forms of CAMs, probably derived from proteolytic shedding, are present in the circulation and their blood levels parallel the amount expressed on the cell surface. In patients with peripheral arterial disease (PAD), increased levels of soluble CAMs have been found during exercise-induced claudication, are associated with the presence, the severity and the extent of atherosclerosis in the arteries of the lower limbs, and portend a worse outcome. These findings have provided new insights into the pathophysiology of PAD and its consequences. However, further large population studies are needed to firmly establish whether increased levels of circulating CAMs give additive information to current risk assessment approaches, and to verify whether PAD patients with elevated levels of circulating CAMs would benefit from any specific therapy.

Haemostasis, inflammation and renal function following exercise in patients with intermittent claudication on statin and aspirin therapy

Background

Previous studies have suggested that exercise in patients with intermittent claudication (IC) may induce a systemic thrombo-inflammatory response. The effect of secondary prevention therapy on this response is unknown. This study aimed to investigate the effects of treadmill exercise on markers of coagulation activation, inflammation and renal function in patients with IC, receiving aspirin and statin therapy compared to healthy controls.

Methods

Samples were taken before, immediately and 1 hour after exercising on a treadmill in 20 patients with IC and 20 healthy volunteers. Interleukin-6 (IL-6), thrombin-anti-thrombin complex (TAT) and fibrin D-dimer were measured by ELISA. High sensitivity CRP (HsCRP) and urinary albumin were measured via a nephelometric technique, urinary protein via a turbidometric assay and N-acetyl-β-D-glucosaminidase (NAG) via a colorimetric assay.

Results

Elevated baseline levels of Hs-CRP, IL-6, white cell counts, D-dimer and urinary NAG occurred in patients with IC compared to volunteers (p > 0.05). Following exercise there was no increase in Hs CRP or IL-6. D-dimer levels significantly increased following exercise in the patients and volunteers. TAT levels increased immediately after exercise in the patient group only and were significantly increased at 1 hour in both patients and volunteers. A transient rise in the protein creatinine ratio occurred in both groups (p < 0.007), and in albumin creatinine ratio in the patient group. There was no change in urinary NAG.

Conclusion

Elevated markers of inflammation occurred in patients with IC on statin and aspirin therapy but these did not increase following exercise. However, acute exercise resulted in a prothrombotic state evident in both groups, although this was more prolonged in patient with IC. The clinical significance of these findings in patients who are known to be at an increased risk of cardiac and other thrombotic event are unclear.

Red blood cell deformability in patients with claudication after pain-free treadmill training

OBJECTIVES

To assess the effect of pain-free treadmill training on red blood cell deformability and walking distance in patients with claudication.

DESIGN

Randomized-controlled trial of exercise training.

SETTING

Patients were recruited from the primary care, vascular outpatient clinic.

PATIENTS

A total of 60 patients with peripheral arterial occlusive disease (stage II according to Leriche-Fontaine) were randomized into the treadmill program or a control group. Fifty-five patients completed the study (27 in the exercising group and 28 in the control group).

INTERVENTIONS

Patients in the exercising group were walking on the treadmill 3 times a week for 3 months. Each session consisted of 1 hour repetitive walking [performed to 85% of the pain-free walking time (PFWT)] was supervised by a qualified physiotherapist.

MAIN OUTCOME MEASUREMENTS

Changes in erythrocyte deformability and treadmill walking performance (PFWT, maximal walking time) were assessed in both groups before the study and after 3 months.

RESULTS

After 3 months of treadmill training, red blood cell deformability in the exercising group significantly increased (P<0.01). No significant changes were seen in the erythrocyte deformability in the control group. PFWT was prolonged by 102% from 191+/-34 to 386+/-60 seconds (P<0.01), and maximal walking time increased by 49% from 438+/-62 to 656+/-79 seconds (P<0.01) in the exercising group, whereas these changes were insignificant in the control group.

CONCLUSIONS

A significant improvement of walking ability over 3 months of pain-free treadmill training is associated with a significant increase in red cell deformability in patients with claudication.

Inflammation and Chlamydia pneumoniae Infection Correlate with the Severity of Peripheral Arterial Disease

BACKGROUND

Our aim was to investigate the association of inflammation and Chlamydia pneumoniae infection with the presence and severity of peripheral arterial disease.

METHODS

Twenty-eight patients whose initial claudication distance (ICD) in the traditional constant-load treadmill test was <200 m, underwent femoral endarterectomy as part of their interventional treatment (group A). Group B consisted of 23 patients whose ICD was >200 m and were put on medication and a daily exercise program. The control group consisted of 30 non-vascular patients of the Ophthalmology Department (group C). We measured the levels of C-reactive protein, fibrinogen, vascular cell adhesion molecule-1 and tumor necrosis factor-alpha, and the titers of IgA and IgG antibodies against C. pneumoniae in the serum of all the patients. Finally, the atheromas and vein segments of group A patients, were immunohistochemically (IHC) examined for the presence of C. pneumoniae.

RESULTS

Peripheral arterial disease (PAD) patients, had significantly higher CRP (p=0.026) and anti-Cp IgA levels (p=0.001) when compared to control subjects, after a multiple linear regression analysis. The odds ratio for the prevalence of femoral atherosclerosis was 3.16 for IgA seropositive patients (CI 1.15-8.67). When comparing group A and group B patients, CRP (p=0.003) and IgA (p=0.011), were significantly correlated with severe PAD. Group A patients with positive immunohistochemical examination of the plaque, had higher anti-Cp IgA levels (p=0.023) and TNF-alpha values (p=0.031), compared to the IHC negative patients. C. pneumoniae was detected in 50% of the femoral atheromas, but in only 3.6% of the veins.

CONCLUSION

This study supports the hypothesis that inflammation (CRP) and chronic C. pneumoniae infection (IgA seropositivity), have an important role in lower limb atherosclerosis and correlate with the severity of the disease.

Augmented levels of CD44 in macrophages from atherosclerotic subjects: a possible IL-6-CD44 feedback loop?

The cell-adhesion molecule CD44 likely participates in atherosclerosis development. We have shown previously that pro-inflammatory cytokines affect CD44 expression. Therefore, this work examined the role of elevated CD44 levels in human macrophages. Macrophages from human atherosclerotic subjects (n=15) showed elevated levels of CD44 transcript and protein (1.5-fold) compared to matched controls (n=15) (P=0.050 and 0.044, respectively). To test whether genetic factors influence CD44 expression, two single nucleotide polymorphisms in the CD44 gene were analyzed but these were not associated with coronary artery disease. We also examined the potential connection between plasma cytokine levels and CD44 expression. In atherosclerotic subjects, elevated CD44 expression correlates (P=0.012) with enhanced macrophage IL-6 secretion (3.13+/-2.5 pg/mL versus 0.32+/-0.16 pg/mL in controls, P=0.021). Additionally, CD44-deficient mice exhibit less circulating IL-6 than wild-type controls (9.8+/-0.7 pg/mL versus 14.3+/-0.7 pg/mL; P=0.032). Furthermore, IL-6 augments CD44 expression in primary human macrophages after 24 h (P=0.038) and 48 h (P=0.015). Taken together, our data show an IL-6-CD44 feedback loop in macrophages. Such a positive feedback loop may aggravate atherosclerosis development.

Does nutrition have a role in peripheral vascular disease?

Peripheral vascular disease (PVD) is a manifestation of systemic atherosclerosis in the lower limbs, and PVD patients have a 3- to 5-fold increased risk of cardiovascular mortality compared with age-matched controls. Nevertheless, recent reports show how PVD patients are undertreated with regard to CVD risk-factor reduction and the use of lipid-lowering or antiplatelet drugs. There is appreciable evidence that demonstrates the beneficial effects of certain nutrients and dietary habits in the prevention of CVD, but there has been little attention paid to the role of nutrients in PVD. The purpose of the present review is to provide an overview of our understanding of how foods could possibly benefit PVD. In the last few decades, several nutrients have arisen as potentially health-promoting in PVD. While nutritional interventions in PVD show positive clinical effects for fish oil, carnitine or vitamin E, others such as olive oil or vitamin C seem to interact only at a biochemical level by decreasing risk factors. Moreover, only epidemiological associations exist for the potential role of fibre, folates or vitamin B6 in this disease. In all cases, the limited data available provide no clear-cut evidence in favour of the clinical benefit of nutritional interventions aimed at reducing risk factors and ameliorating symptoms in PVD patients. No practical recommendations can be given at this stage, and further studies are clearly needed.

Circulating markers of endothelial function in cardiovascular disease

Endothelial dysfunction is a key event in cardiovascular disease. Measurement of endothelial dysfunction in vivo presents a major challenge, but has important implications since it may identify the clinical need for therapeutic intervention, specifically in primary prevention. Several biological markers have been used as indicators of endothelial dysfunction. The soluble adhesion molecules sICAM-1 and sVCAM-1 lack specificity and are increased in inflammatory processes. Both markers are increased in coronary artery disease. sICAM-1 level predicts the risk for cardiovascular disease or diabetes mellitus in healthy individuals. sE-selectin is specific for the endothelium and is increased in coronary artery disease and diabetes mellitus. sE-selectin is also associated with diabetic risk. The endothelium-specific marker, soluble thrombomodulin, is associated with severity of coronary artery disease, stroke or peripheral occlusive arterial disease and is not increased in healthy or asymptomatic subjects. Interestingly, thrombomodulin decreases during treatment of hypercholesterolemia or hyperhomocysteinemia. In contrast, von Willebrand factor is the best endothelial biomarker and predicts risk for ischemic heart disease or stroke.

Exercise training improves low-density lipoprotein oxidability in untrained subjects with coronary artery disease

Exercise training improves low-density lipoprotein oxidability in untrained subjects with coronary artery disease.

OBJECTIVE

To test the hypothesis that regular exercise alters low-density lipoprotein (LDL) oxidability in patients with coronary artery disease.

DESIGN

Longitudinal study.

SETTING

General hospital and community.

PARTICIPANTS

Thirteen patients.

INTERVENTIONS

Training program comprising running bouts twice weekly over 2 months.

MAIN OUTCOME MEASURES

Plasma lipid profile, oxidized LDL, and rate (Ox(rate)) and amount (Ox(amount)) of LDL reaction products were measured at baseline and after 2 months of training. Brachial artery endothelium-dependent and -independent vasodilation was assessed by use of ultrasound.

RESULTS

Lipid profile and oxidized LDL remained unchanged, but mean Ox(rate) and Ox(amount) +/- standard deviation were reduced from 2.5+/-1.5nmol.mgLDL(-1).min(-1) and 120.3+/-75.3nmol/mgLDL at baseline to 0.4+/-0.2nmol.mgLDL(-1).min(-1) and 21.3+/-11.4nmol/mgLDL after training (P<.05), respectively. Brachial artery vasodilation was suggested to be improved, but statistical significance was not reached in the small cohort under study.

CONCLUSIONS

Aerobic training enhances the resistance of LDL to oxidation in patients with coronary artery disease, which may play a role in the favorable effects of exercise.

Analysis of G(-174)C IL-6 polymorphism and plasma concentrations of inflammatory markers in patients with type 2 diabetes and peripheral arterial disease

AIMS

To determine whether the G(-174)C interleukin 6 (IL-6) polymorphism influences the development of peripheral arterial disease (PAD) in individuals with type 2 diabetes. This was investigated by comparing the distribution of G(-174)C genotypes between patients with type 2 diabetes and PAD (PAD+) and those with type 2 diabetes but without PAD (PAD-). Plasma concentrations of IL-6, fibrinogen, C reactive protein (CRP), and vascular endothelial growth factor (VEGF) were also compared in PAD+ and PAD- patients.

METHODS

Blood samples were collected from 146 PAD+ and 144 PAD- patients. SfaNI was used to determine the G(-174)C genotype. Plasma concentrations of IL-6, fibrinogen, CRP, and VEGF were measured by an enzyme linked immunosorbent assay.

RESULTS

The GG genotype was more common in PAD+ patients than in PAD- patients. PAD+ patients also had increased mean plasma concentrations of IL-6, fibrinogen, CRP, and VEGF compared with PAD- patients. Mean plasma concentrations of IL-6, fibrinogen, and CRP in both PAD+ and PAD- patients were higher in those with the GG genotype than in those with the GC or CC genotypes. In contrast, mean plasma concentrations of VEGF in PAD+ and PAD- patients were not significantly different between those with different G(-174)C genotypes.

CONCLUSIONS

These results support a model in which the GG genotype promotes PAD development among individuals with type 2 diabetes by inducing increased release of IL-6. Higher concentrations of IL-6 among those with the GG genotype is associated with increased plasma concentrations of fibrinogen and CRP.

A Preliminary Study on the Effects of Exercising to Maximum Walking Distance on Platelet and Endothelial Function in Patients with Intermittent Claudication

BACKGROUND

Platelet and endothelial activation has been shown to be increased in patients with intermittent claudication (IC). Recent studies have suggested that exercise may induce further platelet activation. The aims of this study were to investigate the effect of exercising to maximum walking distance on platelet and endothelial function in patients with intermittent claudication who were receiving statin and aspirin therapy compared with age matched healthy controls.

METHODS

Platelet aggregation through COX-mediated and thrombin receptor activator peptide (TRAP)-stimulated GPIIb/IIIa pathways was measured by the Ultegra point of care system in 20 patients with IC on aspirin and 20 healthy volunteers before, immediately and 1h after exercising to treadmill maximal walking distance (MWD). Soluble P-selectin, vWF and sICAM were measured using an enzyme linked immuno-sorbent assay technique.

RESULTS

Baseline platelet aggregation was significantly reduced in patients with IC compared to volunteers (p<0.05). In patients, exercising to MWD significantly reduced platelet aggregation (COX, median -5% [range -24 to 13%]; p = 0.02; GPIIIa/IIb, median -13% [range -72 to 33%]; p = 0.02) immediately post-exercise which returned to baseline values at 1 h. There was no change in the healthy volunteers following the same median duration of exercise. Baseline sP-selectin levels were higher in the patients with IC compared to the healthy volunteers [Median values (interquartile range), 42.72 (33.28-54.24) versus 29.16 (24.40-34.10), p = 0.0003] but there were no differences in vWF levels. Both sP-selectin and vWF levels increased significantly in the control and patient group following exercise (p<0.005). sICAM were higher at baseline in the patients with IC but were unchanged following exercise [Median values (interquartile range),560.9 (405.5-739.4) versus 467.0 (325.7-643.4), p<0.05].

CONCLUSION

This study is the first to show that platelet aggregation is reduced immediately following treadmill exercise to maximum walking distance in patients with IC despite a rise in sP-selectin and vWF, suggesting endothelial activation. The inhibition of platelet aggregation after exercise in subjects on antiplatelet and statin therapy suggests that exercise is unlikely to exacerbate platelet thrombus formation in patients with IC.

Study of androgen and atherosclerosis in old-age male

OBJECTIVE

To observe the difference of androgen and inflammatory cytokines level in atherosclerosis and analyse their relations.

METHOD

Both carotid arteries and arteries of lower extremity were subjected to ultrasonic examination by Doppler's method. Those with much atheromatous plaque formation were ranged into case group, and those with normal result formed control group. Total, free testosterone and estradiol were assayed by radioimmunoassay. C reactive protein (CRP) was assayed by nepheloturbidity. Tumor necrosis factor-alpha (TNF-alpha), Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interleukin-10 (IL-10), Interleukin-18 (IL-18), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were assayed by ELISA. The mean difference between two groups and the correlation between free testosterone and cytokines were analysed.

RESULTS

Free testosterone was (6.337+/-3.371) pg/L in case group and (11.375+/-4.733) pg/L in control group, P<0.01. No differences were found in total testosterone and estradiol. CRP was (27.294+/-10.238) mg/L in case group and (12.843+/-6.318) mg/L in control group, P<0.01. IL-6 was (41.700+/-31.385) pg/L in case group and (25.396+/-20.772) pg/L in control group, P<0.05. IL-8 was (89.249+/-58.357) pg/L in case group and (67.873+/-31.227) pg/L in control group, P<0.05. sICAM-1 was (470.491+/-134.078) pg/L in case group and (368.487+/-97.183) pg/L in control group, P<0.01. sVCAM-1 was (537.808+/-213.172) pg/L in case group and (457.275+/-157.273) pg/L in control group, P<0.05. There were no differences in TNF-alpha, IL-10 and IL-18. Correlation analysis showed that FT (free testosterone) had negative correlation with CRP, IL-6 and sICAM-1. Among them FT had well correlation with CRP, correlation index was -0.678.

CONCLUSION

Free testosterone was in negative correlation with atherosclerosis in old-age male. Free testosterone may have the role of anti-atherosclerosis, and this effect was not achieved by its transformation to estradiol. Low free testosterone level was followed by increased level of inflammatory cytokines. Low free testosterones coexist with inflammation and they both affect the process of atherosclerosis in old-age male.

Experimental Model of Pain-Free Treadmill Training in Patients with Claudication

OBJECTIVE

Treadmill training in claudication is often based on walking exercise to a pain threshold or longer to the maximum muscle pain of the lower limbs. This kind of exercise may cause an inflammatory response. The purpose of this study was to determine whether pain-free treadmill training using walking exercise to 85% of the distance to onset of claudication pain can significantly improve pain-free walking distance in patients with intermittent claudication and to evaluate whether this kind of program may induce an inflammatory response leading to the progression of atherosclerosis.

DESIGN

A total of 98 patients aged 50-70 yrs with stable intermittent claudication were randomized into a supervised treadmill training program or a comparison group. Patients in the treatment group participated in 12 wks of supervised treadmill training. We examined the effects of 12 wks of pain-free treadmill training on pain-free walking distance, total leukocyte count, neutrophil count, and microalbuminuria in patients with claudication.

RESULTS

A total of 80 participants completed the program. Exercise rehabilitation increased the time to onset of claudication pain by 119.2%, from 87.4 +/- 38 m to 191.6 +/- 94.8 m (P < 0.001). There was no increase in total leukocyte count, neutrophil count, or microalbuminuria after 12 wks of treadmill exercise (P > 0.05)

CONCLUSION

A pain-free training program can be used in the treatment of claudication as a low-risk program, increasing walking ability without potential harmful effects of ischemia-reperfusion injury.