Intra-Individual Variability of High-Sensitivity C-Reactive Protein Age-Related Variation Over Time in Japanese Subjects

Potential Modulation of Inflammation and Physical Function by Combined Probiotics, Omega-3 Supplementation and Vitamin D Supplementation in Overweight/Obese Patients with Chronic Low-Grade Inflammation: A Randomized, Placebo-Controlled Trial

Obesity is characterized by low-grade inflammation and increased gut permeability. Here, we aim to evaluate the effect of a nutritional supplement on these parameters in subjects with overweight and obesity. A double-blinded, randomized clinical trial was conducted in 76 adults with overweight or obesity (BMI 28 to 40) and low-grade inflammation (high-sensitivity C-reactive protein (hs-CRP) between 2 and 10 mg/L). The intervention consisted of a daily intake of a multi-strain probiotic of Lactobacillus and Bifidobacterium, 640 mg of omega-3 fatty acids (n-3 FAs), and 200 IU of vitamin D (n = 37) or placebo (n = 39), administered for 8 weeks. hs-CRP levels did not change post-intervention, other than an unexpected slight increase observed in the treatment group. Interleukin (IL)-6 levels decreased in the treatment group (p = 0.018). The plasma fatty acid (FA) levels of the arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio and n-6/n-3 ratio (p < 0.001) decreased, and physical function and mobility improved in the treatment group (p = 0.006). The results suggest that hs-CRP may not be the most useful inflammatory marker, but probiotics, n-3 FAs, and vitamin D, as non-pharmaceutical supplements, may exert modest effects on inflammation, plasma FA levels, and physical function in patients with overweight and obesity and associated low-grade inflammation.

Potential Modulation of Inflammation by Probiotic and Omega-3 Supplementation in Elderly with Chronic Low-Grade Inflammation—A Randomized, Placebo-Controlled Trial

Probiotic and omega-3 supplements have been shown to reduce inflammation, and dual supplementation may have synergistic health effects. We investigated if the novel combination of a multi-strain probiotic (containing B. lactis Bi-07, L. paracasei Lpc-37, L. acidophilus NCFM, and B. lactis Bl-04) alongside omega-3 supplements reduces low-grade inflammation as measured by high-sensitivity C-reactive protein (hs-CRP) in elderly participants in a proof-of-concept, randomized, placebo-controlled, parallel study (NCT04126330). In this case, 76 community-dwelling elderly participants (median: 71.0 years; IQR: 68.0–73.8) underwent an intervention with the dual supplement (n = 37) or placebo (n = 39) for eight weeks. In addition to hs-CRP, cytokine levels and intestinal permeability were also assessed at baseline and after the eight-week intervention. No significant difference was seen for hs-CRP between the dual supplement group and placebo. However, interestingly, supplementation did result in significant increases in the level of the anti-inflammatory marker IL-10. In addition, dual supplementation increased levels of valeric acid, further suggesting the potential of the supplements in reducing inflammation and conferring health benefits. Together, the results suggest that probiotic and omega-3 dual supplementation exerts modest effects on inflammation and may have potential use as a non-pharmacological treatment for low-grade inflammation in the elderly.

Within-person reproducibility of proteoforms related to inflammation and renal dysfunction

Protein biomarkers and microheterogeneity have attracted increasing attention in epidemiological and clinical research. Knowledge of within-person reproducibility over time is paramount to determine whether a single measurement accurately reflects an individual's long-term exposure. Yet, research investigating within-person reproducibility for proteoforms is limited. We investigated the reproducibility of the inflammatory markers C-reactive protein (CRP), serum amyloid A (SAA), and calprotectin (S100A8/9), and the renal function marker cystatin C (CnC) using a novel immuno-MALDI-TOF MS assay. Reproducibility, expressed as intraclass correlation coefficient (ICC), was calculated for 16 proteoforms using plasma samples of the Western Norway B Vitamin Intervention Trial (WENBIT) cohort collected 1-3 y apart from 295 stable angina pectoris (SAP) patients and 16 weeks apart from 38 subjects of the Intervention with Omega Fatty Acids in High-risk Patients with Hypertriglyceridemic Waist (OMEGA) trial with abdominal obesity but no other documented co-morbidities. ICCs for inflammatory markers were lower in WENBIT (CRP: 0.51, SAAt: 0.38, S100At: 0.31) compared to OMEGA subjects (CRP: 0.71, SAAt: 0.73, S100At: 0.48), while comparable for CnCt (WENBIT: 0.69, OMEGA: 0.67). Excluding SAP patients with elevated inflammation (CRP > 10 µg/ml) increased the ICC of SAAt to 0.55. Reduction of the time interval from 3 to 1 y in WENBIT group increased ICCs for all proteoforms. With a few exceptions ICCs did not differ between proteoforms of the same biomarker. ICCs were highest in OMEGA subjects with fair-to-good reproducibility for all markers. Reproducibility of SAA and S100A8/9 proteoforms in the WENBIT cohort was related to inflammation. This work will inform future clinical and epidemiological research which relies on single time point biomarker assessment to investigate inflammation and renal function.

Effect of compliance during periodontal maintenance therapy on c-reactive protein levels: a 6-year follow-up

AIMS

To longitudinally evaluate the effects of compliance during periodontal maintenance therapy (PMT) on C-reactive protein (CRP) levels and its relation to periodontal status.

MATERIALS AND METHODS

A subsample comprising of 30 matched pairs was taken from a previous 6-year longitudinal study under PMT. Pairs were composed of one regular (RC) and one irregular (IC) compliers, matched by age and sex. Periodontal parameters and plasma samples were collected at 3 times: T1[prior to active periodontal therapy (APT)], T2(after APT), and T3(after 6 years). CRP plasma levels were quantified using ELISA.

RESULTS

RC presented better clinical periodontal status, lower recurrence of periodontitis (sites with PD ≥4 mm and CAL ≥3 mm, together with the persistence and/or presence of BOP and/or suppuration, during any of the subsequent recall evaluations) and significant reductions in CRP levels over time [(T1: RC = 3.64 ± 2.13 and IC = 3.92 ± 2.02 mg/L) and (T3: RC = 2.12 ± 1.39 mg/L and IC = 3.71 ± 1.82 mg/L)]. Logistic regression analysis demonstrated that individuals with periodontitis recurrence presented 2.19 higher chances of presenting altered CRP levels (values ≥3 mg/L- T2 to T3) than those without periodontitis recurrence (95%CI:1.16-3.27; p = 0.017).

CONCLUSIONS

Higher CRP plasma levels were associated with higher recurrence of periodontitis and worse clinical periodontal parameters among IC when compared to RC.

Four-year stability of anthropometric and cardio-metabolic parameters in a prospective cohort of older adults

AIM

To examine the medium-term stability of anthropometric and cardio-metabolic parameters in the general population.

MATERIALS & METHODS

Participants were 5160 men and women from the English Longitudinal Study of Ageing (age ≥50 years) assessed in 2004 and 2008. Anthropometric data included height, weight, BMI and waist circumference. Cardio-metabolic parameters included blood pressure, serum lipids (total cholesterol, HDL, LDL, triglycerides), hemoglobin, fasting glucose, fibrinogen and C-reactive protein.

RESULTS

Stability of anthropometric variables was high (all intraclass correlations >0.92), although mean values changed slightly (-0.01 kg weight, +1.33 cm waist). Cardio-metabolic parameters showed more variation: correlations ranged from 0.43 (glucose) to 0.81 (HDL). The majority of participants (71-97%) remained in the same grouping relative to established clinical cut-offs.

CONCLUSION

Over a 4-year period, anthropometric and cardio-metabolic parameters showed good stability. These findings suggest that when no means to obtain more recent data exist, a one-time sample will give a reasonable approximation to average levels over the medium-term, although reliability is reduced.

Acupuncture to Reduce HIV-Associated Inflammation

Background. HIV infection is associated with systemic inflammation that can increase risk for cardiovascular events. Acupuncture has been shown to have immunomodulatory effects and to improve symptoms in persons with inflammatory conditions. Objective. To test the anti-inflammatory effects of an acupuncture protocol that targets the cholinergic anti-inflammatory pathway (CAIP), a neural mechanism whose activation has been shown to reduce the release of proinflammatory cytokines, in persons with HIV-associated inflammation. Design, Setting, Participants, and Interventions. Double-blind, placebo-controlled clinical trial conducted in an outpatient clinic located in a medically underserved urban neighborhood. Twenty-five clinically-stable HIV-infected persons on antiretroviral therapy were randomized to receive once weekly CAIP-based acupuncture or sham acupuncture. Main Outcome Measures. Outcomes included plasma concentrations of high sensitivity C-reactive protein and D-dimer and fasting lipids. Results. Twenty-five participants completed the protocol (treatment group n = 12, control group n = 13). No adverse events related to the acupuncture protocol were observed. Compared to baseline values, the two groups did not significantly differ in any outcome measures at the end of the acupuncture protocol. Conclusions. CAIP-based acupuncture did not favorably modulate inflammatory or lipid parameters. Additional studies are warranted of CAIP-based protocols of different frequencies/durations.

Effects of adverse life events on heart rate variability, cortisol, and C-reactive protein

OBJECTIVE

Our objective was to assess whether self-reported adverse life events during childhood or over the lifespan are associated with altered activity of the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal axis (HPA axis), and the immune system.

METHOD

This study was performed in a population-based cohort of 1094 adults aged 33-79 years, 46.3% male, average age 53 (SD 11.4). Two waves of data were collected at a 2-year interval, enabling replication of the analyses. Cumulative exposure to adverse life events was assessed by means of the List of Threatening Experiences. ANS function was assessed by spectral analysis of heart rate variability in the high-frequency band (HRV-HF). HPA axis function was assessed by 24-h urinary free cortisol (24-h UFC) excretion. Inflammation was assessed by high-sensitive C-reactive protein (hsCRP).

RESULTS

Multiple linear regression analyses did not reveal any significant associations, with the exception of one significant negative association between the lifetime score of adverse life events and HRV-HF β = -0.028; P = 0.037 at baseline, but not at follow up 2 years later.

CONCLUSION

In a large population-based cohort, adverse life events were not consistently associated with HRV-HF, 24-h UFC or (hsCRP).

Intraindividual variability over time in plasma biomarkers of inflammation and effects of long-term storage

PURPOSE

Systemic measures of chronic inflammation, often based on a single blood draw, are frequently used to study the associations between inflammation and chronic diseases such as cancer. However, more information is needed on the measurement error in these markers due to laboratory error, within-person variation over time, and long-term storage.

METHODS

We investigated the intraindividual variability of inflammation markers C-reactive protein (CRP), interleukin-6 (IL-6), and soluble tumor necrosis factor receptors I and II (sTNFRI and II) in a subsample of the Seattle Barrett's esophagus study cohort. Two fasting blood samples were collected between 1995 and 2009 from 360 participants on average 1.8 years apart. CRP, IL-6, and sTNF receptor levels were measured by immunonephelometry, ELISA, and multiplex assays, respectively. Intra- and inter-batch coefficients of variation (CV) were estimated using blinded pooled samples within each batch. Intraclass correlations (ICCs) were computed using random effects ANOVA.

RESULTS

Intra- and inter-batch CVs for the pooled plasma aliquots were low (2.4-8.9 %), suggesting little laboratory variability. Reliability over time was excellent for sTNF receptors (ICCsTNF-RI = 0.89, ICCsTNF-RII = 0.85) and fair-to-good for CRP and IL-6 (ICCCRP = 0.55, ICCIL-6 = 0.57). For samples stored for over 13 years, the ICCs for CRP and IL-6 were decreased but those for sTNF receptors were unaffected.

CONCLUSION

sTNF receptor levels are more stable within person over time than CRP or IL-6. Long-term storage of samples appears to increase the variability of CRP and IL-6 measures, while the reliability of soluble TNF receptor measures was not affected by storage time.

Intraindividual variability of C-reactive protein: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

The intraindividual variability of C-reactive protein (CRP) remains uncertain. Although guidelines suggest stability of serial CRP values comparable to that of cholesterol measures, several studies indicate greater fluctuations of CRP. We sought to compare the intraindividual variability of CRP with that of cholesterol measures using the multi-ethnic study of atherosclerosis (MESA).

METHODS

CRP measurements were available in 760 MESA participants after exclusion of those with comorbidities or medications known to affect CRP or CRP≥10 mg/L. Serial values were available for 255 participants. The intraclass correlation coefficient (ICC) was quantified for CRP, total cholesterol (TC), and non-HDL-cholesterol (non-HDL-C) as the ratio of between-subject variance to the sum of between-subject and within-subject variance. Fluctuation between baseline and follow-up categories was calculated by cross-classifying participants according to baseline tertiles.

RESULTS

The multivariable-adjusted ICC of CRP was 0.62 (95% CI, 0.55-0.68), significantly lower than that of TC (0.75; 95% CI, 0.70-0.81; p = 0.001 vs CRP) and non-HDL-C (0.76; 95% CI, 0.71-0.81; p = 0.001 vs CRP). 51% of participants in the highest baseline CRP tertile had discordant values on follow-up, while 54% and 27% were discordant in the middle and lowest baseline CRP tertiles. Among participants with baseline CRP levels exceeding 3 mg/L, a clinical threshold for higher risk, 69% had subsequent measurements falling within a lower risk category.

CONCLUSIONS

In the MESA cohort, intraindividual variation of CRP was significantly greater than that for cholesterol measures. Our results suggest that further evaluation of CRP variability is needed in large prospective studies using shorter intervals between measurements.

Reliability of serum biomarkers of inflammation from repeated measures in healthy individuals

BACKGROUND

Biomarkers of low-grade systemic inflammation are used to study the associations of inflammation with chronic diseases, including cancer. However, relatively little is known about the intraindividual variability of most of these measures.

METHODS

Fasting serum samples, collected at baseline and the end of ≥3-week washout periods in a four-diet crossover feeding trial, were used to measure the inflammatory markers high sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-8, and soluble TNF receptor (sTNFR) I and II. Participants included 62 men and women for analyses of IL-6 and CRP and 56 for analyses of IL-8, TNF-α, and sTNFRs, aged 20 to 40, who were free of factors known to influence inflammation, for example, chronic disease, medication use, heavy alcohol use, smoking, and obesity (body mass index >30 kg/m(2)). Intraclass correlations (ICC) were estimated using random effects ANOVA, across all four time points (~6 weeks apart).

RESULTS

ICCs for TNF-α and sTNFR I and II were very high: ICC = 0.92 [95% confidence interval (CI), 0.89-0.96], 0.92 (95% CI, 0.88-0.95), and 0.90 (95% CI, 0.85-0.94), respectively. ICCs for IL-8 and hsCRP were 0.73 (95% CI, 0.63-0.83) and 0.62 (95% CI, 0.49-0.75), respectively. The ICC for IL-6 was considerably lower, ICC = 0.48 (95% CI, 0.36-0.62). Three measures of IL-6 would be needed to achieve a reliability coefficient (Cronbach α) of 0.75.

CONCLUSIONS

With the exception of IL-6, reliability of all inflammatory markers in our panel was high.

IMPACT

This suggests that a single measure accurately captures the short-term (e.g., 4-6 months) variability within an individual.

Reproducibility of high-sensitivity C-reactive protein as an inflammatory component of metabolic syndrome in Japanese

BACKGROUND

Cutoff points for high-sensitivity C-reactive protein (hs-CRP) as a component of metabolic syndrome (MetS) in Japanese have been proposed as 0.40-0.45 mg/L for men and 0.25-0.35 mg/L for women. However, there are some concerns about the reproducibility of hs-CRP.

METHODS AND RESULTS

Reproducibility of hs-CRP as a component of MetS was examined using receiver-operating characteristic (ROC) curves for diagnosing MetS in 1,274 men and 673 women whose serum levels of hs-CRP were measured twice at annual health screening tests. The Spearman's correlation coefficient between baseline hs-CRP and hs-CRP at the next year's test was 0.68 in men and 0.71 in women. The area under the ROC curves of baseline hs-CRP, hs-CRP at the next year's test, and the mean of the 2 hs-CRP tests for diagnosing baseline MetS were 0.71, 0.71, and 0.72, respectively, in men and 0.75, 0.74, and 0.74, respectively, in women. Optimal cutoff points of baseline hs-CRP, hs-CRP at the next year's test, and the mean of 2 tests for diagnosing baseline MetS were all 0.40 mg/L in men and 0.35 mg/L in women.

CONCLUSIONS

The serum level of hs-CRP was stable enough for use as a measure of the inflammatory component of MetS, and the optimal cutoff point of hs-CRP was 0.40 mg/L for men and 0.35 mg/L for women in a Japanese health-screening population.

Intra-individual variation in serum C-reactive protein over 4 years: an implication for epidemiologic studies

BACKGROUND

Data on long-term intra-individual variability in high-sensitivity C-reactive protein (hsCRP) are needed to determine whether one measurement adequately reflects usual levels in prospective studies of on the etiology of cancer and other chronic diseases; when not reflective, the ability to statistically detect modest to moderate associations is reduced. The authors estimated the size of this source of variability and consequent attenuation of the relative risk (RR).

METHODS

High-sensitivity C-reactive protein (hsCRP) concentration was measured using a high-sensitivity immunoturbidometric assay in sera collected at years 2, 4, and 6 from 50 men in the placebo arm of the Prostate Cancer Prevention Trial (PCPT). After natural logarithm-transformation of hsCRP, analysis of variance was used to estimate the within- and between-individual variances from which the intra-class correlation coefficient (ICC) was calculated.

RESULTS

The observed RR due to an ICC < 1 was calculated by e((ln true RR*ICC)) for a range of true RRs. The 4-year ICC was 0.66. Measuring hsCRP once and assuming no other error, if the true RRs were 1.50, 2.00, and 3.00 when comparing high with low concentration, then the observed RRs would be 1.31, 1.58, and 2.06, respectively.

CONCLUSION

Investigators planning to measure hsCRP only once should design adequately sized studies to preserve inferences for hypothesized modest to moderate RRs.

Discordances among different tools used to estimate cardiovascular risk in postmenopausal women

BACKGROUND

New cardiovascular disease (CVD) risk factors are being recognized and suggested to be included in CVD risk stratification. High-sensitivity C-reactive protein (hs-CRP) and the metabolic syndrome (MetS) are among these risk factors. However, CVD risk classification may be divergent when using different approaches.

OBJECTIVES

To compare differences in CVD risk estimation using the Framingham risk score (FRS), hs-CRP and the presence of the MetS in a group of 109 postmenopausal women in primary CVD prevention.

METHODS

The FRS and presence of the MetS were determined. CVD risk was evaluated with a cardiovascular point scoring system based on Framingham covariables and hs-CRP values (Women's Health Study [WHS] model). The estimated CVD risks based on hs-CRP levels and the WHS model were compared with the FRS.

RESULTS

Using the FRS, 99% of women (n=108) were determined to have a low CVD risk. The MetS was identified in 39.4% (n=43) of the women. When hs-CRP was used alone to estimate CVD risk, 37.6% (n=41) of women were classified as being at low, 33.9% (n=37) at moderate and 28.4% (n=31) at high CVD risk. With the WHS model, 83.5% (n=91), 14.7% (n=16) and 1.8 % (n=2) of women were classified as being at low, moderate and high CVD risk, respectively.

CONCLUSIONS

A substantial number of postmenopausal women showing evidence of the MetS were not identified by the FRS, even though women with the MetS are at higher risk of CVD. Estimation of risk by hs-CRP is significantly divergent when using conventional hs-CRP cutoff values compared with an integrated use in the WHS model.

Very low levels of high-sensitivity C-reactive protein are not bimodally distributed but are significantly related to other metabolic risk factors in Japanese

BACKGROUND

High-sensitivity C-reactive protein (hs-CRP) is an independent risk factor of diabetes and cardiovascular disease and it is proposed as a component of metabolic syndrome. Blood levels of hs-CRP are reported to be much lower in Japanese than in Westerners and bimodally distributed in Japanese.

METHODS

Very low levels of hs-CRP were examined using medical check-up data of 1,360 Japanese men and 821 women whose plasma levels of high-sensitivity C-reactive protein (hs-CRP) were below 10 mg/L.

RESULTS

The distribution of hs-CRP levels were skewed but not bimodal in both men and women and very low levels of hs-CRP were significantly related to waist circumference, systolic blood pressure, diastolic blood pressure, fasting glucose, triglycerides, and low-density lipoprotein cholesterol in both men and women. The area under receiver operating characteristic curve of hs-CRP for diagnosing metabolic syndrome and Spearman's correlation coefficients between hs-CRP and components of metabolic syndrome were comparable to those of components of metabolic syndrome in both men and women.

CONCLUSION

Very low levels of hs-CRP were not bimodally distributed but were significantly related to metabolic risk factors in Japanese.

Tracking of high-sensitivity C-reactive protein after an initially elevated concentration: the JUPITER Study

BACKGROUND

The JUPITER (Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin) trial suggests that increased high-sensitivity C-reactive protein (hsCRP) concentrations may be useful in decisions about the initiation of statin therapy for primary prevention of vascular disease. Although studies of specific populations have suggested that hsCRP is a reliable longitudinal marker, it is unclear how strongly hsCRP tracks in individuals after a single increased concentration.

METHODS

We evaluated tracking of hsCRP in 8901 individuals randomized to placebo in the JUPITER trial. These individuals had screening LDL cholesterol concentrations <130 mg/dL (<3.37 mmol/L) and hsCRP concentrations > or =2 mg/L, with subsequent hsCRP measurements made before randomization; at 13 weeks; 1, 2, 3, and 4 years later; and at trial termination. Longitudinal trends and associations were evaluated nonparametrically with box plots and Spearman correlations. After data transformation to achieve normality, repeated-measures regression models estimated the intraclass correlation of hsCRP, with and without controlling for known demographic, lifestyle, and medical determinants of hsCRP concentration. For comparison, we evaluated tracking of systolic and diastolic blood pressure; total, LDL, and HDL cholesterol; and fasting triglycerides.

RESULTS

The median hsCRP concentration in these untreated individuals showed modest regression to the mean over time, declining from 3.8 mg/L at randomization to 3.4 mg/L at 4 years. Tracking correlations for hsCRP over time were comparable to those for blood pressure and LDL cholesterol, but lower than those for HDL, fasting triglycerides, and total cholesterol. The intraclass correlation for repeated hsCRP measurements was 0.54 (95% CI, 0.53-0.55) without covariate adjustment and 0.50 (95% CI, 0.49-0.51) after adjustment for demographic, lifestyle, and comorbidity determinants.

CONCLUSIONS

Concentrations of hsCRP show strong tracking, even after selection of individuals with initially high values. Without statin therapy, increased concentrations of hsCRP generally remain high over time.