C-reactive protein: a marker or a player?

C-reactive protein and risk of cognitive decline: The REGARDS study

Markers of systemic inflammation are associated with increased risk of cognitive impairment, but it is unclear if they are associated with a faster rate of cognitive decline and whether this relationship differs by race. Our objective was to examine the association of baseline C-reaction protein (CRP) with cognitive decline among a large racially diverse cohort of older adults. Participants included 21,782 adults aged 45 and older (36% were Black, Mean age at baseline 64) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. CRP was measured at baseline and used as a continuous variable or a dichotomous grouping based on race-specific 90th percentile cutoffs. Cognitive measures of memory and verbal fluency were administered every 2 years for up to 12 years. Latent growth curve models evaluated the association of CRP on cognitive trajectories, adjusting for relevant demographic and health factors. We found that higher CRP was associated with worse memory (B = -.039, 95% CI [-.065,-.014]) and verbal fluency at baseline (B = -.195, 95% CI [-.219,-.170]), but not with rate of cognitive decline. After covariate adjustment, the association of CRP on memory was attenuated (B = -.005, 95% CI [-.031,-.021]). The association with verbal fluency at baseline, but not over time, remained (B = -.042, 95% CI [-.067,-.017]). Race did not modify the association between CRP and cognition. Findings suggest that levels of CRP at age 45+, are a marker of cognitive impairment but may not be suitable for risk prediction for cognitive decline.

Estradiol Valerate in COC Has More Favorable Inflammatory Profile Than Synthetic Ethinyl Estradiol: A Randomized Trial

CONTEXT

Combined oral contraceptives (COCs) alter inflammatory status and lipid metabolism. Whether different estrogens have different effects is poorly understood.

OBJECTIVE

We compared the effects of COCs containing ethinyl estradiol (EE) or estradiol valerate (EV) and dienogest (DNG) with those containing DNG only on inflammation and lipid metabolism.

DESIGN

Randomized, controlled, open-label clinical trial.

SETTING

Two-center study in Helsinki and Oulu University Hospitals.

PARTICIPANTS

Fifty-nine healthy, young, nonsmoking women with regular menstrual cycles. Age, body mass index, and waist-to-hip ratio were comparable in all study groups at the beginning. Fifty-six women completed the study (EV + DNG, n = 20; EE + DNG, n = 19; DNG only, n = 17).

INTERVENTIONS

Nine-week continuous use of COCs containing either EV + DNG or EE + DNG, or DNG only as control.

MAIN OUTCOME MEASURES

Parameters of chronic inflammation (high-sensitivity C-reactive protein [hs-CRP], and pentraxin 3 [PTX-3]) and lipid profile (high-density lipoprotein [HDL], low-density lipoprotein [LDL], triglycerides, and total cholesterol).

RESULTS

Serum hs-CRP increased after 9-week use of EE + DNG (mean change ± standard deviation 1.10 ± 2.11 mg/L) compared with EV + DNG (-0.06 ± 0.97 mg/L, P = 0.001) or DNG only (0.13 ± 0.68 mg/L, P = 0.021). Also, PTX-3 increased in the EE + DNG group compared with EV + DNG and DNG-only groups (P = 0.017 and P = 0.003, respectively). In the EE + DNG group, HDL and triglycerides increased compared with other groups (HDL: EE + DNG 0.20 ± 0.24 mmol/L vs EV + DNG 0.02 ± 0.20 mmol/L [P = 0.002] vs DNG 0.02 ± 0.18 mmol/L [P = 0.002]; triglycerides: EE + DNG 0.45 ± 0.21 mmol/L vs EV + DNG 0.18 ± 0.36 mmol/L [P = 0.003] vs DNG 0.06 ± 0.18 mmol/L [P < 0.001]).

CONCLUSIONS

EV + DNG and DNG only had a neutral effect on inflammation and lipids, while EE + DNG increased both hs-CRP and PTX-3 levels as well as triglycerides and HDL.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02352090.

The association of mid-to late-life systemic inflammation with white matter structure in older adults: The Atherosclerosis Risk in Communities Study

We examined whether the pattern of middle- to late-life systemic inflammation was associated with white matter (WM) structural abnormalities in older adults. A total of 1532 participants (age = 76.5; standard deviations = 5.4) underwent 3T brain magnetic resonance imaging to quantify white matter hyperintensity volume and whole-brain WM microstructural integrity (fractional anisotropy, mean diffusivity). High-sensitivity C-reactive protein (CRP), a marker of systemic inflammation, was measured at 3 visits (21 and 14 years before, and concurrent with, neuroimaging). Participants were categorized into 1 of 6 groups based on their 21-year pattern of low (<3 mg/L) versus elevated (≥3 mg/L) CRP. Compared to the group with low CRP at all 3 visits, the group that transitioned from low to elevated CRP during midlife demonstrated greatest white matter hyperintensity volume and poorest WM microstructural integrity, after adjusting for demographic variables and cardiovascular risk factors. Participants with high CRP at all visits also demonstrated greater WM structural abnormalities, but only after accounting for differential attrition. These results suggest that increasing and persistent inflammation in the decades spanning middle-to late-life may promote WM disease in older adults.

The Association of Mid- and Late-Life Systemic Inflammation with Brain Amyloid Deposition: The ARIC-PET Study

BACKGROUND

Although inflammation has been implicated in the pathogenesis of Alzheimer's disease, the effects of systemic inflammation on brain amyloid deposition remain unclear.

OBJECTIVE

We examined the association of midlife and late-life systemic inflammation with late-life brain amyloid levels in a community sample of non-demented older adults from the Atherosclerosis Risk in Communities (ARIC) - PET Study.

METHODS

339 non-demented participants (age: 75 [SD 5]) were recruited from the ARIC Study to undergo florbetapir PET (amyloid) imaging. Blood levels of high sensitivity C-reactive protein (CRP), a marker of systemic inflammation, were measured 22 years (Visit 2), 16 years (Visit 4), and up to 2 years before PET imaging (Visit 5). Elevated brain amyloid deposition (standardized uptake value ratio >1.2) was the primary outcome.

RESULTS

Our primary analyses found no association of midlife and late-life CRP with late-life brain amyloid levels. However, in secondary stratified analyses, we found that higher midlife (Visit 2) CRP was associated with elevated amyloid among males (OR 1.65, 95% CI: 1.13-2.42), and among white (OR 1.33, 95% CI: 1.02-1.75), but not African American, participants (p-interactions<0.05). Among male participants, those who maintained high CRP levels (≥3 mg/L) throughout mid- and late-life were most likely to have elevated brain amyloid (OR, 8.81; 95% CI: 1.23, 62.91).

CONCLUSIONS

Although our primary analysis does not support an association between systemic inflammation and brain amyloid deposition, we found evidence for sex- and race-dependent associations. However, findings from subgroup analyses should be interpreted with caution.

Non-soya legume-based therapeutic lifestyle change diet reduces inflammatory status in diabetic patients: a randomised cross-over clinical trial

The present randomised cross-over clinical trial investigated the effects of two intervention diets (non-soya legume-based therapeutic lifestyle change (TLC) diet v. isoenergetic legume-free TLC diet) on inflammatory biomarkers among type 2 diabetic patients. A group of thirty-one participants (twenty-four women and seven men; weight 74.5 (SD 7.0) kg; age 58.1 (SD 6.0) years) were randomly assigned to one of the two following intervention diets for 8 weeks: legume-free TLC diet or non-soya legume-based TLC diet. The latter diet was the same as the legume-free TLC diet, except that two servings of red meat were replaced with different types of cooked non-soya legumes such as lentils, chickpeas, peas and beans over a period of 3 d per week. The intervention period was followed by a washout period of 4 weeks, after which the groups followed the alternate treatment for 8 weeks. Concentrations of inflammatory markers were measured at baseline and after the intervention periods. Compared with the legume-free TLC diet, the non-soya legume-based TLC diet significantly decreased high-sensitivity C-reactive protein, IL-6 and TNF-α in overweight diabetic patients. The replacement of two servings of red meat by non-soya legumes in the isoenergetic TLC diet for a period of 3 d per week reduced the plasma concentrations of inflammatory markers among overweight diabetic patients, independent of weight change.

Periodontal treatment with topical antibiotics improves glycemic control in association with elevated serum adiponectin in patients with type 2 diabetes mellitus

OBJECTIVES

Chronic inflammation of periodontitis aggravates glycemic control in type 2 diabetic patients through aggravation of insulin resistance. Increased or decreased release of various inflammatory mediators, such as high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and adipokines, such as adiponectin, leptin, and resistin, are presumed to be responsible for developing and progressing insulin resistance. The purpose of this study was to examine the effects of periodontal treatment on glycemic control, serum inflammatory mediators and adipokines in type 2 diabetes patients with periodontitis.

METHODS

Twenty-one type 2 diabetic patients with periodontitis received periodontal treatment with topical antibiotics (intervention group) and 8 patients did not receive periodontal treatment (control group). Periodontal examination, including probing pocket depth (PPD) and bleeding on probing (BOP), and blood sampling were performed at baseline, 2 and 6 months after periodontal treatments. Glycated hemoglobin (HbA1c), hs-CRP, TNF-α, IL-6, adiponectin, leptin, and resistin were analyzed.

RESULTS

In the intervention group, improvements of PPD and BOP, decrease in HbA1c and elevation of serum adiponectin were observed, while in the control group, all parameters were not changed. Generalized linear model revealed that changes of serum adiponectin and TNF-α and change of BOP correlated significantly with the reduction of HbA1c at 6 months after periodontal treatments.

CONCLUSION

The results demonstrated that periodontal treatment improves periodontal status and glycemic control with elevation of serum adiponectin in type 2 diabetic patients. The results suggest that HbA1c is reduced by amelioration of insulin resistance due to elevated serum adiponectin after periodontal treatments.

Effects of icosapent ethyl on lipid and inflammatory parameters in patients with diabetes mellitus-2, residual elevated triglycerides (200-500 mg/dL), and on statin therapy at LDL-C goal: the ANCHOR study

Background

Icosapent ethyl (IPE) is a high-purity prescription form of eicosapentaenoic acid (EPA) ethyl ester indicated as an adjunct to diet to reduce triglyceride (TG) levels in adult patients with severe (≥500 mg/dL) hypertriglyceridemia. ANCHOR was a 12-week, phase 3 study that evaluated the efficacy and safety of IPE in patients (N = 702) with residual high fasting TG levels (≥200 and <500 mg/dL) despite having optimized low-density lipoprotein cholesterol (LDL-C) levels (≥40 and <100 mg/dL) on statin therapy. Among patients randomized to IPE (4 g/day or 2 g/day) or placebo, 514 (73%) had diabetes mellitus.

Methods

A post hoc subgroup analysis of the ANCHOR study was conducted to assess the effects of IPE on median placebo-adjusted percent change from baseline in efficacy end point parameters in 3 subgroups: total (all subjects with diabetes—overall median baseline glycosylated hemoglobin A_1c [A_1c] = 6.8%), better-controlled diabetes (below median baseline A_1c), and less-controlled diabetes (above median baseline A_1c).

Results

Baseline efficacy parameters were similar among all groups except high-sensitivity C-reactive protein (hsCRP), which was higher in the total and less-controlled diabetes groups. Compared with placebo, IPE 4 g/day significantly reduced TG, non-high-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol (VLDL-C), lipoprotein-associated phospholipase A₂, apolipoprotein B (Apo B), total cholesterol, high-density lipoprotein cholesterol, VLDL-TG, oxidized LDL, and remnant-like particle cholesterol in all 3 diabetes groups, LDL-C in the total diabetes group, and hsCRP in the total and less-controlled diabetes groups. Decreases in hsCRP and Apo B were much greater in patients with less-controlled diabetes. There were no significant increases in fasting plasma glucose, A_1c, insulin, or homeostasis model assessment-estimated insulin resistance in any group.

Conclusion

IPE 4 g/day significantly improved lipid and lipid-related parameters without worsening glycemic control in patients with diabetes and mixed dyslipidemia, with possibly greater effects among those with less-controlled diabetes.

Trial registration

Clinicaltrials.gov Identifier NCT01047501

Icosapent ethyl, a pure ethyl ester of eicosapentaenoic acid: effects on circulating markers of inflammation from the MARINE and ANCHOR studies

BACKGROUND

Icosapent ethyl (IPE) is a high-purity prescription form of eicosapentaenoic acid ethyl ester approved by the US Food and Drug Administration as an adjunct to diet to reduce triglyceride (TG) levels in adult patients with severe (≥500 mg/dL) hypertriglyceridemia. In addition to TG-lowering effects, IPE also reduces non-high-density lipoprotein cholesterol and apolipoprotein B levels without significantly increasing low-density lipoprotein cholesterol (LDL-C) in patients with very high TG levels ≥500 mg/dL (MARINE study) and in patients with well-controlled LDL-C and residually high TG levels 200-500 mg/dL (ANCHOR study). This analysis examined the effect of IPE on inflammatory markers in patients from MARINE and ANCHOR.

METHODS

MARINE (N = 229) and ANCHOR (N = 702) were Phase III, double-blind studies that randomized hypertriglyceridemic patients to IPE 4 g/day, 2 g/day, or placebo. This analysis assessed the median placebo-adjusted percentage change from baseline in markers representing various stages of atherosclerotic inflammation such as intercellular adhesion molecule-1 (ICAM-1), oxidized low-density lipoprotein (Ox-LDL), lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP).

RESULTS

Compared to placebo, IPE 4 g/day significantly decreased Ox-LDL (13 %, p < 0.0001, ANCHOR), Lp-PLA(2) (14 %, p < 0.001, MARINE; 19 %, p < 0.0001, ANCHOR), and hsCRP levels (36 %, p < 0.01, MARINE; 22 %, p < 0.001, ANCHOR), but did not significantly change ICAM-1 and IL-6 levels. In the MARINE study, IPE 2 g/day did not significantly change ICAM-1, Ox-LDL, Lp-PLA(2), IL-6, or hsCRP levels. Also, compared to placebo in the ANCHOR study, IPE 2 g/day significantly decreased Lp-PLA(2) levels (8 %, p < 0.0001), but did not significantly change levels of other assessed inflammatory markers.

CONCLUSION

Compared to placebo, in hypertriglyceridemic patients, IPE 4 g/day significantly decreased Ox-LDL, Lp-PLA(2), and hsCRP levels.

Anti-inflammatory effects of enhanced external counterpulsation in subjects with abnormal glucose tolerance

Elevated markers of systemic inflammation are associated with impaired glucose tolerance and type 2 diabetes mellitus. Enhanced external counterpulsation (EECP) has been shown to decrease circulating concentrations of pro-inflammatory markers in coronary artery disease patients. Here we provide novel evidence that EECP intervention also has a beneficial effect on circulating markers of systemic inflammation coincident with improvements in glycemic control in subjects with abnormal glucose tolerance.

Effect of exercise training modality on C-reactive protein in type 2 diabetes

PURPOSE

Type 2 diabetes is associated with increased risk of cardiovascular disease and elevated C-reactive protein (CRP) levels. Aerobic exercise training has been shown to improve CRP; however, there are limited data evaluating the effect of other exercise training modalities (aerobic, resistance, or combination training) in individuals with type 2 diabetes.

METHODS

Participants (n = 204) were randomized to an aerobic exercise (aerobic), resistance exercise (resistance), or a combination of both (combination) for 9 months. CRP was evaluated at baseline and at follow-up.

RESULTS

Baseline CRP was correlated with fat mass, waist circumference, body mass index, and VO(2peak) ̇(P < 0.05). CRP was not reduced after aerobic (0.16 mg·L(-1), 95% confidence interval (CI) = -1.0 to 1.3 mg·L(-1)), resistance (-0.03 mg·L(-1), 95% CI = -1.1 to 1.0 mg·L(-1)), or combination (-0.49 mg·L(-1), 95% CI = -1.5 to 0.6 mg·L(-1)) training compared to control (0.35 mg·L(-1), 95% CI = -1.0 to 1.7 mg·L(-1)). Changes in fasting glucose (r = 0.20, P = 0.009), glycated hemoglobin (HbA1c) (r = 0.21, P = 0.005), and fat mass (r = 0.19, P = 0.016) were associated with reductions in CRP but not with change in fitness or weight (P > 0.05). There were significant trends observed for CRP among tertiles of change in HbA1c (P = 0.009) and body fat (P = 0.040).

CONCLUSIONS

Aerobic, resistance, or a combination of both did not reduce CRP levels in individuals with type 2 diabetes. However, exercise-related improvements in HbA1c, fasting glucose, and fat mass were associated with reductions in CRP.

A review of C-reactive protein: A diagnostic indicator in periodontal medicine

Periodontitis is a local inflammatory process mediating the destruction of periodontal tissues, triggered by bacterial insult. Recent evidence suggests the presence of chronic inflammatory periodontal disease may significantly affect systemic health conditions such as coronary heart disease, stroke, or adverse pregnancy outcome. C-reactive protein (CRP) is an acute phase protein which reflects a measure of the acute phase response. CRP is used as one of the markers of choice in monitoring the acute phase response because it increases to a relatively high concentration compared to basal concentration. CRP has been shown to predict cardiovascular (CV) mortality in recent studies, and elevated CRP levels have been observed in middle-aged patients with periodontitis. Combination of chronic infections like periodontitis with elevated CRP is associated with higher chronic heart diseases. The recognition of the relationship between periodontal diseases and atherosclerotic events is relatively recent and mostly based on the inflammatory hypothesis of atherosclerosis. Periodontal disease is one of the risk factors for cardiovascular disease and possibly one of its causes. Hence, even associations of modest magnitude have a large impact. The cost to the society directly attributable to atherosclerotic sequelae is very large. Periodontitis is treatable; moreover, it is preventable. Experimental conformation of this shows that another widely prevalent and preventable contributor to the burden of cardiovascular disease would be added to the options available of the clinicians and public health practitioners for the control of the epidemic of cardiovascular disease.

Relation of C-reactive protein to endothelial fibrinolytic function in healthy adults

Increased plasma concentrations of C-reactive protein (CRP) independently predict future atherothrombotic events in healthy asymptomatic adults. CRP may promote atherothrombosis by altering fibrinolytic balance; however, the influence of increased plasma CRP concentrations on endothelial fibrinolysis in healthy adults is unclear. We tested the hypothesis that endothelial release of tissue-type plasminogen activator (t-PA) is impaired in adults with increased plasma CRP concentrations independent of other cardiometabolic risk factors. Fifty-four healthy adults were studied: 24 with CRP <1.0 mg/L (low CRP; 18 men and 6 women, 55 ± 2 years old), 18 with CRP 1.0 to 3.0 mg/L (moderate CRP; 8 men and 10 women, 58 ± 2 years old), and 12 with CRP >3.0 mg/L (high CRP; 7 men and 5 women, 56 ± 2 years old). Net endothelial release of t-PA was determined in vivo in response to intrabrachial infusions of bradykinin (125 to 500 ng/min) and sodium nitroprusside (2.0 to 8.0 μg/min). Capacity of the endothelium to release t-PA was significantly lower (∼30%) in the high (0.32 ± 0.5 to 38.9 ± 6.0 ng · 100 ml tissue(-1) · min(-1)) and moderate (-0.05 ± 0.4 to 39.3 ± 5.2 ng · 100 ml tissue(-1) · min(-1)) compared to the low (0.42 ± 0.9 to 61.8 ± 5.2 ng · 100 ml tissue(-1) · min(-1)) CRP group. There was no significant difference in t-PA release between the high and moderate CRP groups. Plasma CRP concentrations were inversely related to t-PA release (r = -0.38, p <0.05). In conclusion, these results indicate that the capacity of the endothelium to release t-PA is decreased in adults with plasma CRP ≥1.0 mg/L. Endothelial fibrinolytic dysfunction may underlie the increased atherothrombotic risk associated with increases in plasma CRP concentrations in otherwise healthy adults.

CRP promotes MMP-10 expression via c-Raf/MEK/ERK and JAK1/ERK pathways in cardiomyocytes

C-reactive protein (CRP) was reported to be a predictor for left ventricular (LV) remodeling. Matrix metalloproteinase (MMP)-10 participates in the LV remodeling process. However, the intrinsic relationship between CRP and MMP-10 in cardiomyocytes remains unclear. The purpose of this study is to observe whether CRP may promote MMP-10 expression, and if so, to clarify signaling pathways to be involved in CRP-induced MMP-10 expression in cardiomyocytes. We observed in cultured cardiomyocytes that CRP at a dose of 5 μg/ml increased MMP-10 expression and activity in a time-dependent manner, as measured by real-time polymerase chain reaction (PCR), western blots, and casein zymography analysis. We hypothesized that signal pathways of mitogen-activated protein kinases (MAPKs) and Janus kinases (JAKs)/signal transducers and activators of transcription (STATs) might be involved in CRP-induced MMP-10 expression. Our results showed that CRP markedly activated c-Raf/MEK/ERK and JAK1/ERK signaling pathways but not JAK1/STAT3 signaling pathway by using the phosphor-specific antibodies against these pathways, and blockages of c-Raf/MEK/ERK and JAK1/ERK signaling pathways by the specific ERK1/2 inhibitor U0126 and JAK1 inhibitor piceatannol could significantly decrease CRP-induced MMP-10 expression. In addition, we demonstrated that the DNA binding sites of AP-1 and STAT3 in the nucleus of cardiomyocytes mediated CRP-induced MMP-10 expression. In conclusion, we demonstrated that CRP promoted MMP-10 expression and activity in cardiomyocytes, and clarified that c-Raf/MEK/ERK and JAK1/ERK signaling pathways were involved in MMP-10 expression regulation via activation of DNA binding sites for AP-1 and STAT3 in cardiomyocytes. Our findings suggest that CRP acts as a predictor for LV remodeling might be associated with its promotion effect on MMP-10 expression and activity.

Argan Oil Exerts an Antiatherogenic Effect by Improving Lipids and Susceptibility of LDL to Oxidation in Type 2 Diabetes Patients

In this study, we investigate the effect of argan oil consumption on serum lipids, apolipoproteins (AI and B), CRP, and LDL susceptibility to oxidation in type 2 diabetic patients which are known to have a high level of cardiovascular risk due to lipid abnormalities and lipid peroxidation. For that, 86 type 2 diabetic patients with dyslipidemia were randomized to one group consuming 25 mL/day of argan oil during 3 weeks and control group consuming 20 g/day of butter in breakfast. After argan oil intervention, serum triglycerides decreased by 11.84%, (P = 0.001), total chol by 9.13%, (P = 0.01), and LDL-chol by 11.81%, (P = 0.02). However, HDL-chol and Apo AI increased (10.51%, P = 0.01 and 9.40%,  P = 0.045, resp.). Susceptibility of LDL to lipid peroxidation was significantly reduced by increasing of 20.95%, (P = 0.038) in lag phase after argan oil consumption. In conclusion, we show for the first time that consumption of argan oil may have an antiatherogenic effect by improving lipids, and the susceptibility of LDL to oxidation in type 2 diabetes patients with dyslipidemia, and can therefore be recommended in the nutritional management of type 2 diabetes.

Developing and Characterizing a Mouse Model of Hepatotoxicity Using Oral Pyrrolizidine Alkaloid (Monocrotaline) Administration, with Potentiation of the Liver Injury by Co-administration of LPS

Oral administration of xenobiotics is preferable for research in In Vivo models because it mimics the real life situation of human subjects. Therefore, oral (po) monocrotaline (MCT) (a common contaminant of dietary supplements)/intraperitoneal (ip) lipopolysaccharides (LPS)-induced liver injury possibly imitates idiosyncratic hepatotoxicity in humans. Cytokines, for example interleukin-1β (IL-1β) and transforming growth factor beta (TGF-β) are known to play a role in the development of toxicity and repair processes, respectively. The purpose of this study was to develop and characterize a model of po MCT/ip LPS hepatotoxicity which may elucidate the mechanisms of injury. ND4 male mice were given MCT (200 mg/kg) followed 4 h later by LPS (6 mg/kg). Blood samples were drawn for plasma chemistry and IL-1β. Animals were euthanized and livers were harvested at different time points. We have shown that MCT/LPS cotreatment results in significant elevation of plasma alanine aminotransferase (ALT), CRP, IL-1β and TGF-β. Histopathological evaluation revealed diffuse degenerative injury. In summary, we have established a reproducible in vivo model of hepatotoxicity by po MCT/ip LPS cotreatment that may closely mimic real life idiosyncratic hepatotoxicity.

Functional and mechanistic integration of infection and the metabolic syndrome

The metabolic syndrome refers to a well defined group of risk factors, including central obesity and inflammation, for the development of diabetes and cardiovascular disease. Interestingly, many studies have recently led to the emergence of somewhat unexpected relationships between several infectious diseases and various aspects of the metabolic syndrome. Our understanding of the mechanisms underlying these interactions is also rapidly developing and some of these are summarized in this article. We will focus first on bacterial infection, and most notably the role of gut microbiota in regulaton of both obesity and inflammation. In particular, we focus on the role of inflammasomes and propose that understanding the role of Toll-like receptors and Nod-like receptors in the pathogenesis of inflammatory disorders with or without infection may provide novel targets for prevention and/or treatment of associated diseases. Secondly, chronic bacterial or viral infection and emerging links with metabolism will be reviewed. Finally, consideratons of biomarkers for metabolic syndrome, in particular lipocalin-2, and their link with infection will be discussed.

High plasma C-reactive protein (CRP) is related to low paraoxonase-I (PON-I) activity independently of high leptin and low adiponectin in type 2 diabetes mellitus

OBJECTIVES

In type 2 diabetes mellitus, circulating C-reactive protein (CRP) is increased, whereas the high density lipoprotein (HDL)-associated, anti-oxidative and anti-inflammatory enzyme, paraoxonase-I, is decreased. Both high CRP and low paraoxonase-I activity may predict cardiovascular disease. It is unknown whether lower paraoxonase-I activity contributes to higher CRP levels in diabetes. In type 2 diabetic and control subjects, we determined the relationship of CRP with paraoxonase-I when taking account of plasma levels of pro- and anti-inflammatory adipokines.

DESIGN AND PATIENTS

In 81 type 2 diabetic patients and 89 control subjects, plasma high-sensitive CRP, serum paraoxonase-I activity (arylesterase activity, assayed as the rate of hydrolysis of phenyl acetate into phenol), plasma leptin, adiponectin, resistin and lipids were determined.

RESULTS

Body mass index (BMI), waist, insulin resistance, triglycerides, CRP, leptin and resistin levels were higher (P < 0.05 to P < 0.001), whereas HDL cholesterol, paraoxonase-I activity and adiponectin levels were lower (P = 0.02 to P < 0.001) in diabetic compared to control subjects. Multiple linear regression analysis demonstrated that, after controlling for age and gender, CRP was inversely related to paraoxonase-I activity (beta = -0.15, P = 0.028) and adiponectin (beta = -0.18, P = 0.009), and positively to leptin (beta = 0.33, P < 0.001) and BMI (beta = 0.22, P = 0.007), independently of the diabetic state (or of fasting glucose or HbA1c), insulin resistance and lipids (P > 0.20 for all).

CONCLUSIONS

Low paraoxonase-I activity is related to higher CRP, independently of adipokines, as well as of obesity and lipids. Low paraoxonase-I activity in type 2 diabetes mellitus may contribute to increased cardiovascular risk via an effect on enhanced systemic low-grade inflammation.

Indoleamine 2,3-dioxygenase activity associates with cardiovascular risk factors: the Health 2000 study

Indoleamine 2,3-dioxygenase (IDO) is an important immunomodulator suppressing the activation of T lymphocytes, and its level in blood is increased in several autoimmune and inflammatory diseases. We have previously shown that this activity associates with several signs and risk factors of atherosclerosis in 24 to 39-year-old females. Now we repeat this analysis in an older population (n = 921, age range 46-76 years), i.e. in a population with more advanced atherosclerosis. IDO activity had a significant positive correlation in both sexes with carotid artery intima/media thickness (IMT), an early marker of atherosclerosis. In females, a significant negative correlation with HDL cholesterol and a positive correlation with triglycerides levels was observed. The association with IMT did not remain significant after adjustment with classical risk factors of atherosclerosis. It is thus concluded that IDO is a sensitive marker of atherosclerosis--or the inflammatory response associated with it--but does not have an independent role in the pathogenesis of this disease.

Label-free detection of antibody-antigen interactions on (R)-lipo-diaza-18-crown-6 self-assembled monolayer modified gold electrodes

Novel (R)-diaza-18-crown-6 has been prepared by a simple two-step synthetic method and characterized for its ability to form a uniform self-assembled monolayer (SAM) on gold as well as to immobilize proteins using atomic force microscopy, quartz crystal microbalance, and electrochemical impedance spectroscopy (EIS) experiments. The (R)-lipo-diaza-18-crown-6 was shown to form a well-defined SAM on gold, which subsequently captures the antibody (Ab) molecules that in turn capture the antigen (Ag) molecules. The Ab molecules studied include antibody C-reactive protein (Ab-CRP) and antibody ferritin (Ab-ferritin) along with their Ag's, i.e., CRP and ferritin. Quantitative detection of the Ab-Ag interactions was accomplished by EIS experiments with a Fe(CN)6(3-/4-) redox probe present. The ratios of the charge-transfer resistances for the redox probe on the SAM-antibody-covered electrode to those with the antigen molecules attached show an excellent linearity for log[Ag] with lower detection limits than those of other SAMs for the electrochemical sensing of proteins.