Elsa M. Hjerkinn

Effect of diet or very long chain ω-3 fatty acids on progression of atherosclerosis, evaluated by carotid plaques, intima-media thickness and by pulse wave propagation in elderly men with hypercholesterolaemia:

Background This randomized study targeted a comparison of the effect of 3-year diet counselling or ω-3 polyunsaturated fatty acid (PUFA) supplementation (2.4g/day) on the progression of atherosclerosis in carotid arteries and on finger pulse wave propagation. Methods Measurements were assessed by high-resolution B-mode ultrasound and a photopletysmographic finger pulse-sensor, respectively. Altogether, 563 elderly men with long-standing hyperlipidaemia were randomized into four groups: controls (no dietary counselling and placebo); dietary counselling (and placebo); ω-3 PUFA supplementation (no dietary counselling); dietary counselling and ω-3 PUFA supplementation. Results In the diet only group, the carotid intima-media thickness increase (0.929 to 0.967 mm) was significantly less than in the control group (0.909 to 0.977 mm), (P=0.018). Significant increase in carotid plaques score and plaques area were observed in all four groups, but without between group differences. Changes in carotid intima-media thickness and in high-density lipoprotein-cholesterol were negatively correlated (adjusted P>0.001). Pulse wave propagation time decreased significantly in the control group (206 to 198 ms; P=0.002), reflecting reduced arterial elasticity. In the group receiving ω-3 PUFA only, pulse wave propagation time increased significantly when compared with the control group (P=0.013). Conclusion Reduced progression in carotid intima-media thickness was observed after dietary counselling, whereas ω-3 PUFA supplementation imposed a favourable effect on arterial elasticity. Eur J Cardiovasc Prev Rehabil 13:325-333

Interleukin-18 is a strong predictor of cardiovascular events in elderly men with the metabolic syndrome. Synergistic effect of inflammation and hyperglycemia

OBJECTIVE—The aim of this study was to investigate the role of inflammatory markers as potential predictors of cardiovascular events in subjects with and without the metabolic syndrome. RESEARCH DESIGN AND METHODS—This was a post hoc analysis from the Diet and Omega-3 Intervention Trial (DOIT), comprising 563 elderly men with (n = 221) and without (n = 342) metabolic syndrome. Circulating inflammatory markers were measured. RESULTS—During 3 years, 68 cardiovascular events were recorded. In the total population, C-reactive protein (CRP) (P < 0.001), interleukin-18 (IL-18) (P = 0.008), and IL-6 (P = 0.003) were elevated in subjects with events. In subjects with metabolic syndrome, IL-18 was the strongest predictor (adjusted odds ratio 2.9 [95% CI 1.1–7.8]). In subjects without metabolic syndrome, only CRP seemed to be an independent predictor (3.3 [1.5–7.3]). There was a significant interaction between fasting glucose and IL-18 (P = 0.008) and IL-6 (P = 0.024) but not CRP. Elevated fasting glucose (>6.2 mmol/l) markedly increased the predictive power of inflammatory markers (IL-18: 5.5 [1.4–21.1], IL-6: 3.5 [1.0–11.8], and CRP: 3.5 [1.0–11.9]). For IL-18, there was a stepwise increase in event rate by quartiles of fasting glucose. CONCLUSIONS—IL-18 was an independent predictor of cardiovascular events in subjects with metabolic syndrome and even more so in the presence of elevated fasting glucose. Our findings suggest a mutually potentiating effect of hyperglycemia and inflammation in cardiovascular risk prediction.

Serum levels of interleukin-18 are reduced by diet and n-3 fatty acid intervention in elderly high-risk men.

Inflammation plays a central role in the development and progression of atherosclerosis, and inflammatory markers have been reported to predict cardiovascular events. Mediterranean-like diet and very long chain omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation have been reported to reduce the risk of cardiovascular mortality and morbidity, but the mechanisms are not fully clarified. The aims of the present study were to investigate the effect of such interventions on serum levels of inflammatory markers, and potential associations with changes in serum fatty acids and anthropometric measures. This was a randomized 2 x 2 factorial-designed trial comparing the effect of 3 years of dietary counseling, n-3 PUFA supplementation (2.4 g/d), or both on different measures of atherosclerosis in elderly high-risk men (N = 563). Levels of interleukin-18 (IL-18) were decreased by diet (-10.5% vs baseline, P = .012 compared with no diet) and by n-3 PUFA supplementation (-9.9% vs baseline, P = .008 compared with placebo). Other measured inflammatory markers were not affected. Changes in IL-18 were significantly correlated to changes in triglycerides (r = 0.20, P < .001), eicosapentaenoic acid (r = -0.14, P = .030), docosahexaenoic acid (r = -0.14, P = .034), body mass index (r = 0.16, P < .001), and waist circumference (r = 0.12, P = .007). In conclusion, levels of IL-18 were significantly reduced by Mediterranean-like diet and n-3 PUFA supplementation. However, the changes correlated only weakly to changes in triglycerides, serum fatty acids, and anthropometric measures. The cardioprotective effects of both interventions might thus in part be explained by reduced levels of IL-18, but probably beyond changes in serum fatty acids and body composition.

Supplementation with fish oil affects the association between very long-chain n-3 polyunsaturated fatty acids in serum non-esterified fatty acids and soluble vascular cell adhesion molecule-1

We have investigated the effect of fish oil supplementation on the association between serum non-esterified fatty acid (NEFA) pattern and atherosclerotic activity. We studied correlations between serum non-esterified very long-chain eicosapentaenoic (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) and biochemical markers of endothelial activation before and after 18-months intervention with fish oil supplementation. The fish oil supplementation consisted of 2.4 g of EPA and DHA per day, with corn oil as placebo. Elderly men ( n =171) with high risk for coronary heart disease were divided into four intervention groups in a factorial design: fish oil supplementation ( n =44), dietary intervention ( n =42), fish oil supplementation+dietary intervention ( n =47) or placebo ( n =38). The composition of fasting NEFA was analysed before and after intervention by GLC. Circulating endothelial markers were analysed by ELISA. A statistically significant positive correlation between the change in serum non-esterified DHA and soluble vascular cell adhesion molecule-1 (sVCAM-1) was found in the pooled group that received fish oil supplementation ( n =91; Spearmans correlation coefficient r =0.24, P =0.02). No such correlation was found in the pooled group without fish oil supplementation ( n =80). Furthermore, there was a significant negative correlation between the change in serum non-esterified EPA and the relative change in sVCAM-1 in the group that did not receive fish oil supplementation ( r =-0.34, P =0.002). No such correlation was found in the group with fish oil supplementation. We conclude that large increase in serum non-esterified EPA and DHA, which can only be attained by supplementation, might increase inflammation in vascular endothelium. A moderate dietary increase in fish oil intake may, however, have an effect on decreasing inflammatory markers.

A randomized clinical trial on n-3 polyunsaturated fatty acids supplementation and all-cause mortality in elderly men at high cardiovascular risk:

Background The benefit of n-3 polyunsaturated fatty acids (PUFA) supplementation for mortality and cardiovascular events after myocardial infarction is well documented, but the effect of n-3 PUFA in Caucasians without established cardiovascular disease is not known. Our aim was to examine the influence of supplementation with eicosapentaenoic acid and docosahexaenoic acid on all-cause mortality and cardiovascular events in elderly men at high-risk of cardiovascular disease. Design In the Diet and Omega-3 Intervention Trial, 563 Norwegian men, 64–76-year old and 72% without overt cardiovascular disease, were randomized to a 3-year 2 × 2 factorial designed clinical trial of diet counseling and/or 2.4 g n-3 PUFA supplementation. The n-3 PUFA arm was placebo-controlled (corn oil). Methods Demographic parameters and classical risk factors were obtained at baseline. Deaths and cardiovascular events were recorded through 3 years, and the effects of n-3 PUFA-intervention on these outcomes were evaluated in pooled groups of the n-3 PUFA-arm. Results There were 38 deaths and 68 cardiovascular events. The unadjusted hazard ratios of all-cause mortality and cardiovascular events were 0.57 (95% confidence interval: 0.29–1.10) and 0.86 (0.57–1.38), respectively. Adjusted for baseline age, current smoking, hypertension, body mass index and serum glucose, hazard ratios were 0.53 (0.27–1.04, P = 0.063) and 0.89 (0.55–1.45, P = 0.641), respectively. Conclusion We observed a tendency toward reduction in all-cause mortality in the n-3 PUFA groups that, despite a low number of participants, reached borderline statistical significance. The magnitude of risk-reduction suggests that a larger trial should be considered in similar populations.

Serum non-esterified very long-chain PUFA are associated with markers of endothelial dysfunction

The objective of this study was to investigate the pattern of serum non-esterified fatty acid (NEFA) fraction in association with atherosclerosis development. We have studied possible relationships between eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) in the NEFA fraction and biochemical markers of endothelial activation or dysfunction. The study population consisted of 152 elderly men with high risk for coronary heart disease. The composition of fasting serum NEFA was analysed by gas-liquid chromatography. Endothelial activation was evaluated using biochemical analyses of some markers of endothelial function. A significant inverse linear association was found between serum non-esterified EPA and DHA, and soluble vascular cell adhesion molecule-1 (sVCAM-1) (P=0.02 and 0.001, respectively). An inverse linear association was found between serum non-esterified AA and sVCAM-1 (P=0.001) and von Willebrand Factor (P=0.005). The significant inverse associations for DHA and AA were independent from the serum content of other NEFAs. Taken together, negative associations were found between sVCAM-1 and the serum levels of non-esterified DHA, EPA and AA. The inverse relation between the levels of sVCAM-1 and very long-chain n-3 fatty acids might indicate an anti-inflammatory effect of the latter.

Adipose tissue pro-inflammatory gene expression is associated with cardiovascular disease

Background:  Obese patients are at high risk of developing cardiovascular disease. Several studies suggest obesity as an independent risk factor. Adipose tissue is now accepted as an endocrine organ that produces and secretes a variety of cytokines, hormones and other metabolic players involved in the pathogenesis of atherosclerosis. Among this versatile group of mediators and effectors of inflammation and atherothrombosis, we have studied the expression of matrix metalloproteinase‐9 (MMP‐9), tissue inhibitor of metalloproteinase‐1 (TIMP‐1), plasminogen activator inhibitor‐1 (PAI‐1), interleukin‐18 (IL‐18) and interleukin‐6 (IL‐6). All these markers, in their circulatory form, have been associated with cardiovascular disease. However, there is no much data available on their expression in adipose tissue in human subjects with and without cardiovascular disease.

Long‐term influence of diet and/or omega‐3 fatty acids on matrix metalloproteinase‐9 and pregnancy‐associated plasma protein‐A in men at high risk of coronary heart disease

Background. Matrix metalloproteinases (MMPs) are important in the atherosclerotic process. The relationship between MMPs and traditional risk factors for cardiovascular disease (CVD) and any influence of lifestyle changes are largely unknown. Objectives. In a factorial design, we studied the effects of 3 years of dietary counselling and/or n‐3 PUFA supplementation (2.4 g/d) on the levels of MMP‐9, tissue inhibitor of metalloproteinase (TIMP‐1) and pregnancy‐associated plasma protein (PAPP‐A) in a population of elderly men at high risk of CVD (n = 563, age 70±6 years). We further explored the association between these markers and different disease entities, carotid intima media thickness (IMT) and traditional risk factors for CVD. Results. Smokers had significantly higher levels of MMP‐9 (p<0.0001), and TIMP‐1 levels were lower in subjects with previous AMI (p = 0.021). MMP‐9 was significantly correlated with LDL‐C and inversely with HDL‐C (both p<0.0001). There were no significant correlations between the measured variables and IMT. Significant reductions in MMP‐9 and PAPP‐A levels after 36 months were found in all study groups, however, with no between‐group differences. Conclusions. The elevated levels of MMP‐9 in smokers and the reduced levels of TIMP‐1 in patients with previous AMI reflect an importance of MMPs in the development of CVD. Intervention with diet and/or n‐3 PUFA supplementation did not influence the levels of MMP‐9, TIMP‐1 or PAPP‐A in the present population.

Effect of diet and omega-3 fatty acid intervention on asymmetric dimethylarginine.

Background and aimImpaired vasodilatation has been suggested to be caused by inhibition of nitric oxide generation by the recently described asymmetric dimethylarginine (ADMA). In the present study we wanted to explore whether n-3 polyunsaturated fatty acid (PUFA) supplementation and/or diet intervention have beneficial influence on endothelial function assessed as plasma levels of ADMA and L-arginine.MethodsA male population (n = 563, age 70 ± 6 yrs) with long-standing hyperlipidemia, characterized as high risk individuals in 1970–72, was included, randomly allocated to receive placebo n-3 PUFA capsules (corn oil) and no dietary advice (control group), dietary advice (Mediterranean type), n-3 PUFA capsules, or dietary advice and n-3 PUFA combined and followed for 3 years. Fasting blood samples were drawn at baseline and the end of the study.ResultsCompliance with both intervention regimens were demonstrated by changes in serum fatty acids and by recordings from a food frequency questionnaire. No influence of either regimens on ADMA levels were obtained. However, n-3 PUFA supplementation was accompanied by a significant increase in L-arginine levels, different from the decrease observed in the placebo group (p < 0.05). In individuals with low body mass index (<26 kg/m2), the decrease in L-arginine on placebo was strengthened (p = 0.01), and the L-arginine/ADMA ratio was also significantly reduced (p = 0.04).ConclusionIn this rather large randomized intervention study, ADMA levels were not influenced by n-3 PUFA supplementation or dietary counselling. n-3 PUFA did, however, counteract the age-related reduction in L-arginine seen on placebo, especially in lean individuals, which might be discussed as an improvement of endothelial function.

Adipose tissue expression of interleukin-18 mRNA is elevated in subjects with metabolic syndrome and independently associated with fasting glucose

ZusammenfassungZIELSETZUNG: Das metabolische Syndrom (MetS) ist eine Ansammlung bestimmter Risikofaktoren, die eine starke Assoziation mit Koronarer Herzkrankheit (KHK) aufweisen. Erhöhte Serumspiegel von Plasminogen Aktivator Inhibitor (PAI-1), Interleukin-6 (IL-6) und IL-18 wurden mit KHK in Verbindung gebracht. Rezente Arbeiten haben gezeigt, dass besonders IL-18 in Patienten mit MetS ein guter Prädiktor füer KHK ist. METHODEN: Wir haben die Expression von PAI-1, IL-6 und IL-18 in subkutanem Fettgewebe in Patienten mit (n = 22) und ohne (n = 36) MetS mittels Real-Time-PCR untersucht. Darüber hinaus haben wir die Expression von IL-18 in Makrophagen in einem in vitro Modell für Hyperglykämie analysiert. Nach Isolation von Monozyten und Differenzierung zu Makrophagen wurde die Expression von IL-18 mittels Real-Time-PCR analysiert. ERGEBNISSE: Die Expression von IL-18 im subkutanen Fettgewebe von Patienten mit MetS ist erhöht (p < 0.05). Eine multivariate Analyse zeigte, dass Nüchtern-Blutzucker die einzige der MetS Komponenten ist, die unabhängig mit IL-18 Expression im Fettgewebe assoziiert ist (p < 0.05). Die Makrophagen im hyperglykämen Milieu hatten eine deutlich höhere IL-18 Expression (p < 0.01), als jene im normoglykämen Milieu. SCHLUSSFOLGERUNG: Unsere Daten sprechen sprechen füer eine spezielle inflammatorische Situation im subkutanen Fettgewebe von Patienten mit MetS, die möglicherweise von Hyperglykämie beeinflusst wird. Makrophagen im subkutanen Fettgewebe könnten zumindest teilweise der zelluläre Ursprung für die erhöhte IL-18 Produktion sein. Zusammen mit rezenten Arbeiten, die IL-18 als Prädiktor füer KHK identifiziert haben, stärken unsere Daten die Möglichkeit einer wichtigen Rolle füer IL-18 als Verbindungsglied zwischen MetS und Atherosklerose.SummaryBACKGROUND: The metabolic syndrome (MetS) is a cluster of risk factors that are highly associated with increased risk for cardiovascular disease (CVD). Increased serum levels of plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6) and IL-18 have been reported to be associated with CVD. Recently, IL-18 has been shown to be predictive for cardiovascular events in subjects with MetS. We have investigated the expression of PAI-1, IL-6 and IL-18 in subcutaneous adipose tissue (AT) of subjects with (n = 22) and without (n = 36) MetS. Furthermore, we have analysed the expression of IL-18 in monocyte-derived macrophages (MDMs) in an in vitro model of hyperglycaemia. METHODS: We studied the expression of PAI-1, IL-6 and IL-18 in biopsies of subcutaneous adipose tissue using Real-time PCR. After isolation and cultivation of MDMs, expression of IL-18 was determined by Real-time PCR. RESULTS: Expression of IL-18 was increased in subcutaneous AT of subjects with MetS (p < 0.05). Multivariate analysis revealed fasting plasma glucose to be the only MetS component being independently associated with expression of IL-18 in AT (p < 0.05). Exposure to hyperglycaemia, increased in expression of IL-18 in MDMs (p < 0.01). CONCLUSION: Our findings suggest that subjects with MetS have a particular inflammatory pattern in AT, possibly driven by fasting glucose. MDMs might - at least in part - be the cellular source of this increased expression. Together with recent reports, showing IL-18 to be predictive for cardiovascular events, our findings could provide the basis for further research of the role of IL-18 as a link and possible target in the association between MetS and atherosclerosis.