C-Reactive Protein Gene Polymorphisms, C-Reactive Protein Blood Levels, and Cardiovascular Disease Risk

Methylation patterns associated with C-reactive protein in racially and ethnically diverse populations

Systemic low-grade inflammation is a feature of chronic disease. C-reactive protein (CRP) is a common biomarker of inflammation and used as an indicator of disease risk; however, the role of inflammation in disease is not completely understood. Methylation is an epigenetic modification in the DNA which plays a pivotal role in gene expression. In this study we evaluated differential DNA methylation patterns associated with blood CRP level to elucidate biological pathways and genetic regulatory mechanisms to improve the understanding of chronic inflammation. The racially and ethnically diverse participants in this study were included as 50% White, 41% Black or African American, 7% Hispanic or Latino/a, and 2% Native Hawaiian, Asian American, American Indian, or Alaska Native (total n = 13,433) individuals. We replicated 113 CpG sites from 87 unique loci, of which five were novel (CADM3, NALCN, NLRC5, ZNF792, and cg03282312), across a discovery set of 1,150 CpG sites associated with CRP level (p < 1.2E-7). The downstream pathways affected by DNA methylation included the identification of IFI16 and IRF7 CpG-gene transcript pairs which contributed to the innate immune response gene enrichment pathway along with NLRC5, NOD2, and AIM2. Gene enrichment analysis also identified the nuclear factor-kappaB transcription pathway. Using two-sample Mendelian randomization (MR) we inferred methylation at three CpG sites as causal for CRP levels using both White and Black or African American MR instrument variables. Overall, we identified novel CpG sites and gene transcripts that could be valuable in understanding the specific cellular processes and pathogenic mechanisms involved in inflammation.

Measurement of cumulative high-sensitivity C-reactive protein and monocyte to high-density lipoprotein ratio in the risk prediction of type 2 diabetes: a prospective cohort study

BACKGROUND

Converging data have suggested that monocytic inflammation and C-reactive protein (CRP) are biologically intertwined processes and are involved in diabetogenesis. This study aimed to investigate the association between systemic inflammation assessed by joint cumulative high-sensitivity C-reactive protein (CumCRP) and monocyte to high-density lipoprotein ratio (CumMHR) and incident type 2 diabetes (T2D) and their predictive value for T2D in a general population.

METHODS

A total of 40,813 nondiabetic participants from a prospective real-life cohort (Kailuan Study, China) were followed biennially from 2010/2011 until December 31, 2020. Multivariable Cox regression analyses were conducted to evaluate the adjusted hazard ratios (aHRs) of incident diabetes.

RESULTS

During a median follow-up of 7.98 (IQR: 5.74-8.87) years, 4848 T2D cases developed. CumMHR and CumCRP were alone or jointly associated with incident T2D after adjusting for potential confounders. Elevated CumMHR levels significantly increased the risk of incident diabetes in each CumCRP strata (P-interaction: 0.0278). Participants with concomitant elevations in CumMHR and CumCRP levels had the highest risk (aHR: 1.71, 95% CI 1.52-1.91) compared to both in the low strata. Notably, the coexposure-associated T2D risk was modified by age, sex, hypertension, dyslipidemia, and prediabetes status. C-statistics increased from 0.7377 to 0.7417 when CumMHR and CumCRP were added into the multivariable-adjusted model, with a net reclassification improvement (%) of 12.39 (9.39-15.37) (P < 0.0001).

CONCLUSIONS

Cumulative hsCRP and MHR were both independently and jointly associated with an increased risk of T2D and their addition to established risk factors should improve risk prediction and reclassification of diabetes.

Potential blood markers as screening tools for subjects with low back pain: an age- and gender-matched cross-sectional analysis

BACKGROUND

Mechanical and inflammatory factors were suggested as the causes of spine degeneration and low back pain (LBP). Previous studies partly reported the association of LBP with inflammation. However, none of them compared patients with LBP and asymptomatic subjects in terms of complete blood count and inflammatory markers in detail. We aimed to analyze the association of serum white blood cell (WBC) count, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) with chronic LBP by comparing the patients with chronic LBP and age- and gender-matched asymptomatic subjects.

METHODS

Lumbar intervertebral disc degeneration and vertebral end-plates were evaluated using Pfirrmann grading and Modic classification on lumbar spine magnetic resonance images, respectively. Serum WBC counts, CRP levels, and ESRs were recorded from chart reviews.

RESULTS

We included 147 patients with chronic LBP and 101 asymptomatic subjects. Patients with chronic LBP had significantly higher serum neutrophil, monocyte, and basophil counts, higher neutrophil-to-lymphocyte ratio, higher ESR, and lower serum CRP levels compared to the asymptomatic subjects. Serum monocyte and basophil cell counts and ESR were the most remarkable predictive factors for chronic LBP, severe IVDD, and Modic changes. Higher serum monocyte and basophil cell counts and higher serum ESR above cut-off values of 0.42 × 103/μL, 0.025 × 103/μL, and 3.5 mm/hour could be used as screening tools for subjects with persistent LBP in primary care.

DISCUSSION

Higher serum monocyte and basophil counts and serum ESR above new cut-off values should highlight the need to obtain early spinal imaging to prevent chronicity in patients with LBP.

Serum C-reactive protein greater than 75 mg/dL as an early available laboratory predictor of severe COVID-19: A systematic review

INTRODUCTION

Severe COVID-19 management is still challenging. Having a laboratory factor to predict the severity of a patient's condition can be very useful in how to approach each patient. There have been studies concentrating on the correlation between serum C-reactive protein (CRP) level and COVID-19 severity but we aim to reach a threshold for CRP in disease severity determination.

METHODS

We conducted a thorough search on PubMed, Web of Science and Google Scholar databases from early 2019 to October 2021, and 323 studies were assessed for eligibility in three phases. We used the Newcastle-Ottawa Scale to examine the validity of the studies. The t-test was applied for the CRP level cutoffs.

RESULTS

Eventually, 11 articles and 1615 patients were included in this systematic review. Our analysis evaluated combined mean, median, and standard deviation of severe patients' CRP to be respectively 73.37, 53.80, and 47.936. Based on the combined mean, 75 mg/dL was suggested as an initial threshold for baseline CRP in hospitalized patients for developing severe conditions.

CONCLUSION

This study recommends that COVID-19 patients with on-admission serum CRP levels of 75 mg/dL and more are likely associated with severe conditions. Thus, anti-inflammatory agents and further following may be helpful in these patients.

Rare functional variants in the CRP and G6PC genes modify the relationship between obesity and serum C-reactive protein in white British population

BACKGROUND

C-reactive protein (CRP) is a sensitive biomarker of inflammation with moderate heritability. The role of rare functional genetic variants in relation to serum CRP is understudied. We aimed to examine gene mutation burden of protein-altering (PA) and loss-of-function (LOF) variants in association with serum CRP, and to further explore the clinical relevance.

METHODS

We included 161,430 unrelated participants of European ancestry from the UK Biobank. Of the rare (minor allele frequency <0.1%) and functional variants, 1,776,249 PA and 266,226 LOF variants were identified. Gene-based burden tests, linear regressions, and logistic regressions were performed to identify the candidate mutations at the gene and variant levels, to estimate the potential interaction effect between the identified PA mutation and obesity, and to evaluate the relative risk of 16 CRP-associated diseases.

RESULTS

At the gene level, PA mutation burdens of the CRP (β = -0.685, p = 2.87e-28) and G6PC genes (β = 0.203, p = 1.50e-06) were associated with reduced and increased serum CRP concentration, respectively. At the variant level, seven PA alleles in the CRP gene decreased serum CRP, of which the per-allele effects were approximately three to seven times greater than that of a common variant in the same locus. The effects of obesity and central obesity on serum CRP concentration were smaller among the PA mutation carriers in the CRP (pinteraction  = 0.008) and G6PC gene (pinteraction  = 0.034) compared to the corresponding non-carriers.

CONCLUSION

PA mutation burdens in the CRP and G6PC genes are strongly associated with decreased serum CRP concentrations. As serum CRP and obesity are important predictors of cardiovascular risks in clinics, our observations suggest taking rare genetic factors into consideration might improve the delivery of precision medicine.

The role of probiotic supplementation in inflammatory biomarkers in adults: an umbrella meta-analysis of randomized controlled trials

OBJECTIVE

Despite the increasing evidence for probiotics' anti-inflammatory effects, the results of meta-analyses remain inconsistent. The present umbrella meta-analysis aimed to investigate the effects of probiotic supplementation on inflammatory biomarkers.

METHODS

We performed a wide-ranging systematic search in several databases, including PubMed, Web of Science, Scopus, EMBASE, and Google Scholar up to April 2023. The overall effect sizes were calculated using effect size (ES) values and their corresponding confidence intervals (CI).

RESULTS

Out of a total of 580 related articles, 39 studies were qualified for inclusion in the analysis. The results of the analysis revealed a significant reduction of C-reactive protein (CRP) (ES = -1.02; 95% CI: -1.23, -0.80, p < 0.001; I2: 94.1%, p < 0.001), TNF-α (ES = -0.35; 95% CI: -0.50, -0.20, p < 0.001; I2: 75.6%, p < 0.001), and interleukin-6 (IL-6) levels (ES = -0.36; 95% CI: -0.59, -0.13, p = 0.002; I2: 85.6%, p < 0.001), following probiotic supplementation.

CONCLUSION

Probiotic supplementation significantly reduced serum concentrations of TNF-a, CRP, and IL-6. Thus, probiotic supplementation can be considered adjuvant therapy to alleviate inflammation in various inflammatory conditions.

Combined Association of Novel and Traditional Inflammatory Biomarkers With Carotid Artery Plaque: GlycA Versus C-Reactive Protein (ELSA-Brasil)

Elevated levels of glycoprotein acetylation (GlycA) and C-reactive protein (CRP) have been associated with carotid artery plaque (CAP). However, it is not yet established if elevations in both inflammatory biomarkers provide incremental association with CAP. This study aimed evaluate the cross-sectional association of high CRP and GlycA with CAP at baseline participants from the ELSA-Brasil adult cohort. Participants with information on CRP, GlycA, and CAP with neither previous cardiovascular disease nor CRP >10 mg/L were included. High GlycA and CRP were defined as values within upper quintile and >3 mg/L, respectively. Participants were classified into 4 groups: 1. nonelevated CRP/GlycA (reference group); 2. elevated CRP alone; 3. elevated GlycA alone; and 4. both elevated. The analysis included 4,126 participants with median age of 50 years-old, being 54.2% of women. Prevalence of CAP was 36.1%. Participants with high CRP had the highest frequency of obesity, whereas participants with high GlycA presented higher cardiovascular risk factor burden and were more likely to have CAP than the reference group (odds ratio [OR] 1.39, 95% confidence interval [CI] 1.11 to 1.73), persisting after multivariable adjustment (OR 1.37, 95% CI 1.02 to 1.83). Participants with both elevated CRP and GlycA were more likely to have CAP in crude (OR 1.35, 95% CI 1.10 to 1.65) but not in adjusted models. The findings suggest potential different biologic pathways between inflammation and carotid atherosclerosis: high GlycA was associated with CAP whereas high CRP was more associated with obesity.

C-Reactive Protein: Pathophysiology, Diagnosis, False Test Results and a Novel Diagnostic Algorithm for Clinicians

The current literature provides a body of evidence on C-Reactive Protein (CRP) and its potential role in inflammation. However, most pieces of evidence are sparse and controversial. This critical state-of-the-art monography provides all the crucial data on the potential biochemical properties of the protein, along with further evidence on its potential pathobiology, both for its pentameric and monomeric forms, including information for its ligands as well as the possible function of autoantibodies against the protein. Furthermore, the current evidence on its potential utility as a biomarker of various diseases is presented, of all cardiovascular, respiratory, hepatobiliary, gastrointestinal, pancreatic, renal, gynecological, andrological, dental, oral, otorhinolaryngological, ophthalmological, dermatological, musculoskeletal, neurological, mental, splenic, thyroid conditions, as well as infections, autoimmune-supposed conditions and neoplasms, including other possible factors that have been linked with elevated concentrations of that protein. Moreover, data on molecular diagnostics on CRP are discussed, and possible etiologies of false test results are highlighted. Additionally, this review evaluates all current pieces of evidence on CRP and systemic inflammation, and highlights future goals. Finally, a novel diagnostic algorithm to carefully assess the CRP level for a precise diagnosis of a medical condition is illustrated.

Mutations on a conserved distal enhancer in the porcine C-reactive protein gene impair its expression in liver

C-reactive protein (CRP) is an evolutionary highly conserved protein. Like humans, CRP acts as a major acute phase protein in pigs. While CRP regulatory mechanisms have been extensively studied in humans, little is known about the molecular mechanisms that control pig CRP gene expression. The main goal of the present work was to study the regulatory mechanisms and identify functional genetic variants regulating CRP gene expression and CRP blood levels in pigs. The characterization of the porcine CRP proximal promoter region revealed a high level of conservation with both cow and human promoters, sharing binding sites for transcription factors required for CRP expression. Through genome-wide association studies and fine mapping, the most associated variants with both mRNA and protein CRP levels were localized in a genomic region 39.3 kb upstream of CRP. Further study of the region revealed a highly conserved putative enhancer that contains binding sites for several transcriptional regulators such as STAT3, NF-kB or C/EBP-β. Luciferase reporter assays showed the necessity of this enhancer-promoter interaction for the acute phase induction of CRP expression in liver, where differences in the enhancer sequences significantly modified CRP activity. The associated polymorphisms disrupted the putative binding sites for HNF4α and FOXA2 transcription factors. The high correlation between HNF4α and CRP expression levels suggest the participation of HNF4α in the regulatory mechanism of porcine CRP expression through the modification of its binding site in liver. Our findings determine, for the first time, the relevance of a distal regulatory element essential for the acute phase induction of porcine CRP in liver and identify functional polymorphisms that can be included in pig breeding programs to improve immunocompetence.

Association of C-reactive protein gene polymorphisms with the risk of ischemic stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

The heterogeneous, complex condition known as ischemic stroke (IS) is brought on by the interaction of a number of risk factors and genetic variables. The association between C-reactive protein (CRP) gene polymorphisms and IS has, however, been the subject of inconsistent findings. Therefore, we conducted a meta-analysis to comprehensively address possible associations of CRP genes with the risk of IS.

METHODS

A comprehensive literature search for all the published articles was performed in electronic databases including PubMed, EMBASE, Cochrane Library, and Google Scholar from January 1, 1950 to June 30, 2022. Odds ratio (OR) with 95% Confidence interval (CIs) along with fixed/random effect models were used to calculate summary estimates.

RESULTS

Twelve case-control studies totalling 3880 IS cases and 5233 controls were included for the association of CRP gene polymorphisms (rs1800947, rs1130864, rs3093059, rs2794521, and rs1205). Across all genotyping models, we discovered that rs1130864, rs3093059, rs2794521, and rs1205SNPs were not substantially related to IS risk. A trend for significant association for rs1800947 under dominant (OR = 1.19; 95% CI = 0.97 to 1.48), recessive (OR = 1.49; 95% CI = 0.71 to 3.14) and allelic model (OR = 1.21; 95% CI = 0.99 to 1.48) was observed. However, protective association for rs1130864 under dominant (OR = 0.80; 95% CI = 0.70 to 0.91) and rs3093059 under allelic model (OR = 0.18; 95% CI = 0.14 to 0.22) was found.

CONCLUSION

Our thorough study revealed that the CRP gene variants rs1800947, rs1130864, rs3093059, rs2794521, and rs1205 could not be related to the risk of ischemic stroke. However, additional research must focus on the rs1800947 polymorphisms in a particular group.

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.

Value of Diagnostic Tools in the Diagnosis of Osteomyelitis: Pilot Study to Establish an Osteomyelitis Score

Osteomyelitis (OM) remains one of the most feared complications in bone surgery and trauma. Its diagnosis remains a major challenge due to lack of guidelines. The aim of this study was to prospectively analyze the value of the most common and available diagnostic tools and to establish an OM score to derive treatment recommendations. All patients with suspected OM were included in a prospective pilot study. All patients underwent blood sampling for C-reactive protein and white blood cell count analysis. Magnetic resonance imaging (MRI), and microbiologic and histopathologic samples, were taken from representative sites of initial debridement. All patients were treated according to their OM test results and followed for at least one year. Subsequently, the value of individual or combined diagnostic tools was analyzed in patients with confirmed OM and in patients in whom OM was ruled out. Based on these findings, an OM score was developed that included MRI, microbiology, and histopathology. The score identified all control patients and all but one OM patient, resulting in a correct diagnosis of 93.3%, which was validated in a second independent larger cohort. This was the first study to analyze the value of the most commonly used tools to diagnose OM. The proposed OM score provides a simple scoring system to safely interpret test results with high accuracy.

Association of - 717 A > G (rs2794521) CRP polymorphism with high cardiovascular risk by C-reactive protein in systemic lupus erythematosus patients

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease where genetic factors have been related to SLE susceptibility and disease severity. CRP polymorphisms have been associated with high C-reactive protein (CRP) serum levels, cardiovascular disease (CVD), and high clinical disease activity in SLE patients; however, the evidence is still inconclusive.

OBJECTIVE

This study was aimed to assess the association of the - 717 A > G, - 409 G > A, + 1444 C > T, and + 1846 C > T CRP polymorphisms with genetic susceptibility, clinical disease activity, and CVD risk in Mexican-mestizo SLE patients.

METHODS

A comparative cross-sectional study was conducted on 369 unrelated women: 183 with SLE according to the 1997 SLE-ACR criteria and 186 healthy subjects (HS). The clinical disease activity was assessed by the Mex-SLEDAI score; CRP and lipid profile were quantified by turbidimetry and colorimetric-enzymatic assays, respectively. The CRP polymorphisms genotyping was carried out by allelic discrimination.

RESULTS

SLE patients with - 717 AA genotype had higher CRP serum levels than SLE carriers of AG and GG genotypes (AA = 5 mg/L vs. AG = 3.2 mg/L vs. GG = 2.4 mg/L; p = 0.01), and the AA genotype was associated with high CVD risk by CRP in SLE patients (OR = 3; CI: 1.2-7.6; p < 0.01).

CONCLUSIONS

The - 717 A > G CRP polymorphism is a risk factor for high CRP levels and high CVD risk in Mexican-mestizo SLE patients. Key Points • Cardiovascular disease is one of the major causes of death in SLE patients due to the higher prevalence of traditional and non-traditional cardiovascular risk factors. • C-reactive protein is a liver-derived acute-phase protein suggested as one powerful independent risk predictor factor for cardiovascular disease. • Single nucleotide polymorphisms in CRP have been suggested as genetic susceptibility factors that could modify the SLE pathophysiology outcomes. • Mexican-mestizo SLE patients carrying the -717 A>G CRP AA genotype had 3-fold high cardiovascular disease risk than SLE patients with AG or GG genotypes.

Association of high-sensitivity C-reactive protein and diabetic nephropathy in patients with type 2 diabetes: a Mendelian randomization study

INTRODUCTION

Observational studies support the relationship between C-reactive protein (CRP) level and diabetic nephropathy (DN) in patients with diabetes. The research question regarding whether the relationship between serum high-sensitivity C-reactive protein (hsCRP) level and DN is causal lacks experimental evidence. Therefore, this study aimed to evaluate the causality between hsCRP and DN based on Mendelian randomization (MR) analysis.

RESEARCH DESIGN AND METHODS

A total of 2332 participants with type 2 diabetes from the Taiwan Biobank database was analyzed. Genetic risk scores (GRSs), which comprise four validated CRP loci as two instrumental variables, were calculated as unweighted and weighted scores to evaluate the causal relationship of hsCRP with DN risk. The two-stage regression model was used to estimate OR and 95% CI.

RESULTS

The analyses of the observational study showed that the hsCRP level was significantly associated with DN after multivariate adjustment (adjusted OR 1.15; 95% CI 1.01 to 1.32). Unweighted/weighted GRSs for log-transformed hsCRP satisfied MR assumptions 1 and 3, respectively; that is, a significant association with hsCRP was observed but that with DN was absent (adjusted OR 1.00, 95% CI 0.92 to 1.09; 1.00, 0.72 to 1.39, respectively). The MR analyses demonstrated that a 1-unit increase in the log-transformed genetically predicted hsCRP by unweighted and weighted GRSs was associated with DN, demonstrating ORs of 1.80 (95% CI 1.51 to 2.14) and 1.67 (95% CI 1.40 to 1.98), respectively.

CONCLUSIONS

The current study provided experimental evidence that hsCRP level was causally related to DN. These findings suggest that the elevated hsCRP may be a causal risk factor for DN in patients with type 2 diabetes.

Temporal relationship between atherogenic dyslipidemia and inflammation and their joint cumulative effect on type 2 diabetes onset: a longitudinal cohort study

BACKGROUND

Concurrent atherogenic dyslipidemia and elevated inflammation are commonly observed in overt hyperglycemia and have long been proposed to contribute to diabetogenesis. However, the temporal relationship between them and the effect of their cumulative co-exposure on future incident type 2 diabetes (T2D) remains unclear.

METHODS

Longitudinal analysis of data on 52,224 participants from a real-world, prospective cohort study (Kailuan Study) was performed to address the temporal relationship between high-sensitivity C-reactive protein (hsCRP) and the atherogenic index of plasma (AIP, calculated as triglyceride/high-density lipoprotein) in an approximately 4-year exposure period (2006/2007 to 2010/2011). After excluding 8824 participants with known diabetes, 43,360 nondiabetic participants were included for further analysis of the T2D outcome. Cox regression models were used to examine the adjusted hazard ratios (aHRs) upon the cumulative hsCRP (CumCRP) and AIP (CumAIP) in the exposure period.

RESULTS

In temporal analysis, the adjusted standardized correlation coefficient (β1) of hsCRP_2006/2007 and AIP_2010/2011 was 0.0740 (95% CI, 0.0659 to 0.0820; P < 0.001), whereas the standardized correlation coefficient (β2) of AIP_2006/2007 and hsCRP_2010/2011 was - 0.0293 (95% CI, - 0.0385 to - 0.0201; P < 0.001), which was significantly less than β1 (P < 0.001). During a median follow-up of 7.9 years, 5,118 T2D cases occurred. Isolated exposure to CumAIP or CumCRP was dose-dependently associated with T2D risks, independent of traditional risk factors. Significant interactions were observed between the median CumAIP (- 0.0701) and CumCRP thresholds (1, 3 mg/L) (P = 0.0308). Compared to CumAIP < - 0.0701 and CumCRP < 1 mg/L, those in the same CumAIP stratum but with increasing CumCRP levels had an approximately 1.5-fold higher T2D risk; those in higher CumAIP stratum had significantly higher aHRs (95% CIs): 1.64 (1.45-1.86), 1.87 (1.68-2.09), and 2.04 (1.81-2.30), respectively, in the CumCRP < 1, 1 ≤ CumCRP < 3, CumCRP ≥ 3 mg/L strata. Additionally, the T2D risks in the co-exposure were more prominent in nonhypertensive, nondyslipidemic, nonprediabetic, or female participants.

CONCLUSIONS

These findings suggest a stronger association between elevated hsCRP and future AIP changes than vice versa and highlight the urgent need for combined assessment and management of chronic inflammation and atherogenic dyslipidemia in primary prevention, particularly for those with subclinical risks of T2D.

Relation of CRP gene variants to altered risk of Helicobacter pylori - associated chronic gastritis: A case-control study in Tunisia

BACKGROUND

We investigated the association between CRP variants and chronic gastritis in H. pylori-infected patients at the allele, genotype, and haplotype levels. This was also assessed according to serum hs-CRP levels.

METHODS

Study subjects consisted of 77 H. pylori-infected patients and 96 H. pylori-negative controls. Genotyping of the CRP rs1572970, rs876537, rs2794520, rs2808630, rs1130864, rs1417938, rs7553007, and rs4285692 variants were analyzed by real-time PCR.

RESULTS

Significantly higher MAF and increased risk of chronic gastritis were associated with rs1130864, rs1417938, and rs7553007, which persisted after controlling for key covariates. Significant differences in the genotype distribution of rs1130864, rs1417938, and rs7553007 were also seen between H. pylori-infected patients and healthy controls. Increased risk of H. pylori-associated chronic gastritis was associated with carriage of rs1130864 C/T, and more with T/T genotype carriers, as well as with rs1417938 T/A and A/A genotype carriers. Functionally, the distribution of rs1130864 and rs1417938 genotypes were significantly different between H. pylori-infected patients and controls in the low hs-CRP (<6 mg/L) group. CRP haplotype analysis identified Block 1 (rs1572970, rs876537, rs2794520), and Block 2 (rs2808630, rs1130864, rs1417938) associated with H. pylori infection. Haplotypes ACC (Block 1) and TTA and TTT (Block 2) were positively associated with H. pylori-associated chronic gastritis with low hs-CRP levels.

CONCLUSION

Altered serum levels of hs-CRP, stemming in part from the presence of specific genetic variants in CRP gene, modulate the risk of H. pylori infection.

Genetic variation in C-reactive protein (CRP) gene is associated with retinopathy and hypertension in adolescents with type 1 diabetes

BACKGROUND AND AIMS

Elevated concentration of CRP has been associated with the risk of diabetes as well as cardiovascular events and microvascular complications in T1D patients. We hypothesize that the +1846 C > T CRP gene polymorphism may have impact on the risk of T1D and/or its complications.

METHODS

We have examined 400 young patients with T1D and 250 healthy age-matched controls. The +1846 C > T CRP gene polymorphism was genotyped by ARMS-PCR method. The analysis covers microvascular complications, concentrations of serum pro- and anti-inflammatory markers, adhesion molecules, proangiogenic factor as well as blood pressure.

RESULTS

CT genotype (OR = 1.799) and T allele (OR = 1.733) are associated with increased risk of T1D, while CC genotype decreases the risk of this condition (OR = 0.458). Moreover, increased risk of hypertension corresponds with TT and T variant (OR = 3.116 and OR = 1.830, resp.) while CC genotype is decreasing the risk (OR = 0.547). Furthermore, CT variant is connected with lower risk of retinopathy (OR = 0.512) whereas TT variant decreases the risk of this complication (OR = 2.228). Our data also implies various effects of CRP +1846 C > T polymorphism on the inflammatory status of T1D patients.

CONCLUSIONS

Although further studies are required, the +1846 C > T CRP gene polymorphism could be considered a genetic marker to predict susceptibility to retinopathy and hypertension in T1D adolescents.

An Exploratory Critical Review on TNF-α as a Potential Inflammatory Biomarker Responsive to Dietary Intervention with Bioactive Foods and Derived Products

This review collects and critically examines data on the levels of tumour necrosis factor-alpha (TNF-α) in lean, overweight and obese subjects, and the effects of intervention with different foods and food products containing bioactive constituents in overweight/obese individuals. We additionally explore the influence of different single nucleotide polymorphisms (SNPs) on TNF-α levels and compare the response to food products with that to some anti-obesity drugs. Our aim was to provide an overview of the variability, consistency, and magnitude of the reported effects of dietary factors on TNF-α, and to envisage the reliability of measuring changes in the levels of this cytokine as a biomarker responsive to food intervention in association with the reduction in body weight. Regarding the circulating levels of TNF-α, we report: (i) a large intra-group variability, with most coefficients of variation (CV%) values being ≥30% and, in many cases, >100%; (ii) a large between-studies variability, with baseline TNF-α values ranging from <1.0 up to several hundred pg/mL; (iii) highly variable effects of the different dietary approaches with both statistically significant and not significant decreases or increases of the protein, and the absolute effect size varying from <0.1 pg/mL up to ≈50 pg/mL. Within this scenario of variability, it was not possible to discern clear differentiating limits in TNF-α between lean, overweight, and obese individuals or a distinct downregulatory effect on this cytokine by any of the different dietary approaches reviewed, i.e., polyunsaturated fatty acids (PUFAs), Vitamin-D (VitD), mixed (micro)nutrients, (poly)phenols or other phytochemicals. Further, there was not a clear relationship between the TNF-α responses and body weight changes. We found similarities between dietary and pharmacological treatments in terms of variability and limited evidence of the TNF-α response. Different factors that contribute to this variability are discussed and some specific recommendations are proposed to reinforce the need to improve future studies looking at this cytokine as a potential biomarker of response to dietary approaches.

Transitional changes in the structure of C-reactive protein create highly pro-inflammatory molecules: Therapeutic implications for cardiovascular diseases

C-reactive protein (CRP) is the prototypic acute-phase reactant that has long been recognized almost exclusively as a marker of inflammation and predictor of cardiovascular risk. However, accumulating evidence indicates that CRP is also a direct pathogenic pro-inflammatory mediator in atherosclerosis and cardiovascular diseases. The 'CRP system' consists of at least two protein conformations with distinct pathophysiological functions. The binding of the native, pentameric CRP (pCRP) to activated cell membranes leads to a conformational change resulting in two highly pro-inflammatory isoforms, pCRP* and monomeric CRP (mCRP). The deposition of these pro-inflammatory isoforms has been shown to aggravate the localized tissue injury in a broad range of pathological conditions including atherosclerosis and thrombosis, myocardial infarction, and stroke. Here, we review recent findings on how these structural changes contribute to the inflammatory response and discuss the transitional changes in the structure of CRP as a novel therapeutic target in cardiovascular diseases and overshooting inflammation.

Osteoprotegerin and MTHFR gene variations in rheumatoid arthritis: association with disease susceptibility and markers of subclinical atherosclerosis

We aimed to explore whether the rs2073618 variant (G1181C) of the osteoprotegerin (OPG) gene and the methylenetetrahydrofolate reductase (MTHFR) rs1801131 (A1298AC) and rs1801133 (C677T) gene polymorphisms contribute to rheumatoid arthritis (RA) susceptibility and RA related subclinical atherosclerosis. Overall 283 RA patients and 595 healthy controls (HC) were genotyped for common variants of the OPG and MTHFR genes using PCR based assays. Clinical and laboratory parameters were recorded following thorough chart review. Surrogate markers of subclinical atherosclerosis (Carotid/Femoral intima media thickness/plaque formation) along with traditional risk factors for atherosclerosis were assessed in all RA patients and 280HC. Increased prevalence of the CC genotype of the rs2073618 variant was detected in RA patients vs HC (42.4% vs. 33%, p-value: 0.04). RA patients with high serum titers of rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) antibodies displayed increased prevalence of the CC genotype of the rs2073618 variant of the OPG gene compared to HC (48.6% and 47.5 vs 33.3%, p-values: 0.0029and 0.0077 respectively). Of interest, this genotype turned to be associated with higher carotid IMT scores (0.872 ± 0.264 vs 0.816 ± 0.284, p-value: 0.01) and marginally with higher rates of carotid plaque formation (66% vs 54.1%, p = 0.06). The MTHFR 1298CC genotype was more prevalent only in the anti-CCP positive group compared to HC, with no associations detected with markers of subclinical atherosclerosis, following adjustment for traditional cardiovascular (CVD) risk factors. Reduced rates of carotid/femoral plaque formation were detected among RA patients harboring the MTHFR TT genotype (52.4 vs 72.7, p-value: 0.009, respectively). This association remained significant following adjustment for classical CVD risk factors (OR [95% CI 0.364 [0.173–0.765], p-value: 0.008). Genetic variations of the osteoprotegerin and MTHFR genes seem to increase susceptibility for seropositive RA and potentially contribute to subclinical atherosclerosis linked to RA. Larger studies are needed to confirm these findings.

CRP Serum Levels Are Associated with High Cardiometabolic Risk and Clinical Disease Activity in Systemic Lupus Erythematosus Patients

Systemic lupus erythematosus (SLE) patients have a higher frequency of cardiovascular risk factors such as high C-reactive protein (CRP) levels than the general population. CRP is considered a cardiovascular disease marker that could be related to SLE clinical disease activity. This study aimed to assess the association between CRP with cardiometabolic risk and clinical disease activity in SLE patients. A comparative cross-sectional study was conducted in 176 female SLE patients and 175 control subjects (CS) with median ages of 38 and 33 years, respectively; SLE patients were classified by the 1997 SLE-ACR criteria, and the clinical disease activity by the Mexican-SLEDAI (Mex-SLEDAI). CRP and lipid profile (triglycerides, cholesterol, HDL-C, and LDL-C) were quantified by turbidimetry and colorimetric-enzymatic assays, respectively. SLE patients had higher CRP levels than CS (SLE: 5 mg/L vs. CS = 1.1 mg/L; p < 0.001). In SLE patients, CRP levels ≥ 3 mg/L were associated with a higher risk of cardiometabolic risk status assessed by LAP index (OR = 3.01; IC: 1.04−8.7; p = 0.04), triglycerides/HDL-C index (OR = 5.2; IC: 2.1−12.8; p < 0.001), Kannel index (OR = 3.1; IC: 1.1−8.1; p = 0.03), Castelli index (OR = 6.6; IC: 2.5−17.8; p < 0.001), and high clinical disease activity (OR = 2.5: IC: 1.03−6.2; p = 0.04; and β coefficient = 5.8; IC: 2.5−9.4; R2 = 0.15; p = 0.001). In conclusion, high CRP levels were associated with high cardiometabolic risk and clinical disease activity in SLE patients.

Inflammatory markers in clinical practice

Inflammation is the general defense response of the body against various harmful irritations. Diagnosis of the inflammatory process and monitoring of its treatment is based on a combination of clinical and laboratory findings. Biochemical inflammatory markers usually serve to support the diagnosis of the infection, to monitor it, and to monitor the effectiveness of anti-infective treatment. The inflammatory marker should be selected according to the clinical condition with regard to the treachery and deficiencies of the markers, with knowledge of their dynamics and with regard to the length of the anamnesis. As an optimal procedure for detecting bacterial infection, it is recommended to screen for several acute phase proteins. The role of the physician is to determine when, under which circumstances, and which markers to have examined, with a view to ensuring that the patient is correctly diagnosed in time and receives appropriate treatment, and on the other hand, that he is not unnecessarily iatrogenized and that the medical facility does not lose money unnecessarily.

Methylenetetrahydrofolate (MTHFR), the One-Carbon Cycle, and Cardiovascular Risks

The 5-10-methylenetetrahydrofolate reductase (MTHFR) enzyme is vital for cellular homeostasis due to its key functions in the one-carbon cycle, which include methionine and folate metabolism and protein, DNA, and RNA synthesis. The enzyme is responsible for maintaining methionine and homocysteine (Hcy) balance to prevent cellular dysfunction. Polymorphisms in the MTHFR gene, especially C677T, have been associated with various diseases, including cardiovascular diseases (CVDs), cancer, inflammatory conditions, diabetes, and vascular disorders. The C677T MTHFR polymorphism is thought to be the most common cause of elevated Hcy levels, which is considered an independent risk factor for CVD. This polymorphism results in an amino acid change from alanine to valine, which prevents optimal functioning of the enzyme at temperatures above 37 °C. Many studies have been conducted to determine whether there is an association between the C677T polymorphism and increased risk for CVD. There is much evidence in favour of this association, while several studies have concluded that the polymorphism cannot be used to predict CVD development or progression. This review discusses current research regarding the C677T polymorphism and its relationship with CVD, inflammation, diabetes, and epigenetic regulation and compares the evidence provided for and against the association with CVD.

The Complex Role of C-Reactive Protein in Systemic Lupus Erythematosus

C-reactive protein (CRP) is well-known as a sensitive albeit unspecific biomarker of inflammation. In most rheumatic conditions, the level of this evolutionarily highly conserved pattern recognition molecule conveys reliable information regarding the degree of ongoing inflammation, driven mainly by interleukin-6. However, the underlying causes of increased CRP levels are numerous, including both infections and malignancies. In addition, low to moderate increases in CRP predict subsequent cardiovascular events, often occurring years later, in patients with angina and in healthy individuals. However, autoimmune diseases characterized by the Type I interferon gene signature (e.g., systemic lupus erythematosus, primary Sjögren’s syndrome and inflammatory myopathies) represent exceptions to the general rule that the concentrations of CRP correlate with the extent and severity of inflammation. In fact, adequate levels of CRP can be beneficial in autoimmune conditions, in that they contribute to efficient clearance of cell remnants and immune complexes through complement activation/modulation, opsonization and phagocytosis. Furthermore, emerging data indicate that CRP constitutes an autoantigen in systemic lupus erythematosus. At the same time, the increased risks of cardiovascular and cerebrovascular diseases in patients diagnosed with systemic lupus erythematosus and rheumatoid arthritis are well-established, with significant impacts on quality of life, accrual of organ damage, and premature mortality. This review describes CRP-mediated biological effects and the regulation of CRP release in relation to aspects of cardiovascular disease and mechanisms of autoimmunity, with particular focus on systemic lupus erythematosus.

C-reactive protein as an effector molecule in Covid-19 pathogenesis

The current pandemic caused by SARS‐CoV‐2 virus infection is known as Covid‐19 (coronavirus disease 2019). This disease can be asymptomatic or can affect multiple organ systems. Damage induced by the virus is related to dysfunctional activity of the immune system, but the activity of molecules such as C‐reactive protein (CRP) as a factor capable of inducing an inflammatory status that may be involved in the severe evolution of the disease, has not been extensively evaluated. A systematic review was performed using the NCBI‐PubMed database to find articles related to Covid‐19 immunity, inflammatory response, and CRP published from December 2019 to December 2020. High levels of CRP were found in patients with severe evolution of Covid‐19 in which several organ systems were affected and in patients who died. CRP activates complement, induces the production of pro‐inflammatory cytokines and induces apoptosis which, together with the inflammatory status during the disease, can lead to a severe outcome. Several drugs can decrease the level or block the effect of CRP and might be useful in the treatment of Covid‐19. From this review it is reasonable to conclude that CRP is a factor that can contribute to severe evolution of Covid‐19 and that the use of drugs able to lower CRP levels or block its activity should be evaluated in randomized controlled clinical trials.

Biomarkers of Post-COVID Depression

The COVID-19 pandemic is spreading around the world and 187 million people have already been affected. One of its after-effects is post-COVID depression, which, according to the latest data, affects up to 40% of people who have had SARS-CoV-2 infection. A very important issue for the mental health of the general population is to look for the causes of this complication and its biomarkers. This will help in faster diagnosis and effective treatment of the affected patients. In our work, we focused on the search for major depressive disorder (MDD) biomarkers, which are also present in COVID-19 patients and may influence the development of post-COVID depression. For this purpose, we searched PubMed, Scopus and Google Scholar scientific literature databases using keywords such as 'COVID-19', 'SARS-CoV-2', 'depression', 'post-COVID', 'biomarkers' and others. Among the biomarkers found, the most important that were frequently described are increased levels of interleukin 6 (IL-6), soluble interleukin 6 receptor (sIL-6R), interleukin 1 β (IL-1β), tumor necrosis factor α (TNF-α), interferon gamma (IFN-γ), interleukin 10 (IL-10), interleukin 2 (IL-2), soluble interleukin 2 receptor (sIL-2R), C-reactive protein (CRP), Monocyte Chemoattractant Protein-1 (MCP-1), serum amyloid a (SAA1) and metabolites of the kynurenine pathway, as well as decreased brain derived neurotrophic factor (BDNF) and tryptophan (TRP). The biomarkers identified by us indicate the etiopathogenesis of post-COVID depression analogous to the leading inflammatory hypothesis of MDD.

How Are Epigenetic Modifications Related to Cardiovascular Disease in Older Adults?

The rate of aging has increased globally during recent decades and has led to a rising burden of age-related diseases such as cardiovascular disease (CVD). At the molecular level, epigenetic modifications have been shown recently to alter gene expression during the life course and impair cellular function. In this regard, several CVD risk factors, such as lifestyle and environmental factors, have emerged as key factors in epigenetic modifications within the cardiovascular system. In this study, we attempted to summarized recent evidence related to epigenetic modification, inflammation response, and CVD in older adults as well as the effect of lifestyle modification as a preventive strategy in this age group. Recent evidence showed that lifestyle and environmental factors may affect epigenetic mechanisms, such as DNA methylation, histone acetylation, and miRNA expression. Several substances or nutrients such as selenium, magnesium, curcumin, and caffeine (present in coffee and some teas) could regulate epigenetics. Similarly, physical inactivity, alcohol consumption, air pollutants, psychological stress, and shift working are well-known modifiers of epigenetic patterns. Understanding the exact ways that lifestyle and environmental factors could affect the expression of genes could help to influence the time of incidence and severity of aging-associated diseases. This review highlighted that a healthy lifestyle throughout the life course, such as a healthy diet rich in fibers, vitamins, and essential elements, and specific fatty acids, adequate physical activity and sleep, smoking cessation, and stress control, could be useful tools in preventing epigenetic changes that lead to impaired cardiovascular function.

Genetic ablation of C-reactive protein gene confers resistance to obesity and insulin resistance in rats

AIMS/HYPOTHESIS

Besides serving as a traditional inflammatory marker, C-reactive protein (CRP) is closely associated with the development of obesity, diabetes and cardiovascular diseases as a metabolic and inflammatory marker. We hypothesise that CRP protein directly participates in the regulation of energy and glucose metabolism rather than just being a surrogate marker, and that genetic deficiency of CRP will lead to resistance to obesity and insulin resistance.

METHODS

Crp gene deletion was achieved by transcription activator-like effector nuclease (TALEN) technology in rats. The Crp knockout animals were placed on either a standard chow diet or a high-fat diet. Phenotypic changes in body weight, glucose metabolism, insulin sensitivity, energy expenditure and inflammation condition were examined. The central impact of CRP deficiency on leptin and insulin hypothalamic signalling, as well as glucose homeostasis, were examined via intracerebral ventricular delivery of leptin and CRP plus glucose clamp studies in the wild-type and Crp knockout rats.

RESULTS

CRP deficiency led to a significant reduction in weight gain and food intake, elevated energy expenditure and improved insulin sensitivity after exposure to high-fat diet. Glucose clamp studies revealed enhanced hepatic insulin signalling and actions. Deficiency of CRP enhanced and prolonged the weight-reducing effect of central injected leptin and promoted the central and peripheral roles of leptin. By contrast, reinstatement of CRP into the hypothalamus of the knockout rats attenuated the effects of central leptin signalling on insulin sensitivity and peripheral glucose metabolism.

CONCLUSIONS/INTERPRETATION

This study represents the first line of genetic evidence that CRP is not merely a surrogate blood marker for inflammation and metabolic syndromes but directly regulates energy balance, body weight, insulin sensitivity and glucose homeostasis through direct regulation of leptin's central effect and hypothalamic signalling.

Preliminary evidence for a race-based stress reduction intervention for Black women at risk for cardiovascular disease

OBJECTIVE

Despite evidence that chronic stress, racism, and discrimination impact the well-being and the risk for cardiovascular disease (CVD) in Black women, there are few evidence-based interventions that improve well-being and reduce the risk for CVD in women of minority groups. The purpose of this pilot study was to evaluate the psychobehavioral and anti-inflammatory benefit of a race-based stress reduction program "Resilience, Stress, and Ethnicity (RiSE) for Black women at risk for CVD.

METHODS

Black women were recruited from the Chicagoland community and randomized to either the 8-week RiSE intervention (n = 40) or control group (n = 34). Participants were assessed for coping strategies, psychological distress, and blood levels of TNF-alpha and high sensitivity C-reactive protein (hsCRP) at baseline and at 4 and 8 weeks after baseline.

RESULTS

Participation in RiSE was associated with a more rapid decline in the use of avoidance coping (b = -0.3585, SE = 0.1705, p < .01). Reductions over time in TNF-alpha (b = -0.0163, SE = .0087, p = .08) and hsCRP (b= -0.4064, SE = 0.2270, p = .08) approached statistical significance.

CONCLUSIONS

Findings provide preliminary evidence in Black women at risk for CVD that RiSE contributes to decreases in avoidance coping. Although preliminary, these results suggest RiSE to be an effective intervention to promote improved coping associated with racism and discrimination in minorities.

Quantile-dependent expressivity of serum C-reactive protein concentrations in family sets

Background

“Quantile-dependent expressivity” occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., C-reactive protein, CRP) is high or low relative to its distribution. We have previously shown that the heritabilities (h²) of coffee and alcohol consumption, postprandial lipemia, lipoproteins, leptin, adiponectin, adiposity, and pulmonary function are quantile-specific. Whether CRP heritability is quantile-specific is currently unknown.

Methods

Serum CRP concentrations from 2,036 sibships and 6,144 offspring-parent pairs were analyzed from the Framingham Heart Study. Quantile-specific heritability from full-sib (β_FS, h² ={(1 + 8r_spouseβ_FS)^0.5 − 1}/(2r_spouse)) and offspring-parent regression slopes (β_OP, h² = 2β_OP/(1 + r_spouse)) were estimated robustly by quantile regression with nonparametric significance determined from 1,000 bootstrap samples.

Results

Quantile-specific h² (±SE) increased with increasing percentiles of the offspring’s age- and sex-adjusted CRP distribution when estimated from β_OP (P_trend = 0.0004): 0.02 ± 0.01 at the 10th, 0.04 ± 0.01 at the 25th, 0.10 ± 0.02 at the 50th, 0.20 ± 0.05 at the 75th, and 0.33 ± 0.10 at the 90th percentile, and when estimated from β_FS (P_trend = 0.0008): 0.03±0.01 at the 10th, 0.06 ± 0.02 at the 25th, 0.14 ± 0.03 at the 50th, 0.24 ± 0.05 at the 75th, and 0.53 ± 0.21 at the 90th percentile.

Conclusion

Heritability of serum CRP concentration is quantile-specific, which may explain or contribute to the inflated CRP differences between CRP (rs1130864, rs1205, rs1800947, rs2794521, rs3091244), FGB (rs1800787), IL-6 (rs1800795, rs1800796), IL6R (rs8192284), TNF-α (rs1800629) and APOE genotypes following CABG surgery, stroke, TIA, curative esophagectomy, intensive periodontal therapy, or acute exercise; during acute coronary syndrome or Staphylococcus aureus bacteremia; or in patients with chronic rheumatoid arthritis, diabetes, peripheral arterial disease, ankylosing spondylitis, obesity or inflammatory bowel disease or who smoke.

Inflammatory biomarker relationships with helper T cell GPR15 expression and cannabis and tobacco smoking

OBJECTIVE

Smoking is associated with numerous inflammatory and autoimmune conditions. The goal of this study was to examine whether increased expression of G-protein-coupled receptor 15 (GPR15) on helper T cells in smokers could predispose to these conditions through its relationship with inflammatory biomarkers.

METHODS

We used flow cytometric measurement of GPR15⁺CD3⁺CD4⁺ helper T cells and serum assays for C-reactive protein (CRP) and 17 cytokines drawn from peripheral blood samples from a cohort of n = 62 primarily African American young adults (aged 27-35 years). These variables were examined cross-sectionally in conjunction with serum biomarkers of tobacco (cotinine) and cannabis (tetrahydrocannabinol) use and lifestyle factors potentially impacting immune function in correlational analyses and linear regression models.

RESULTS

Tobacco and cannabis smoking were strongly associated with increased GPR15 expression on helper T cells (p < 0.001), which was in turn was strongly associated with the ratio of pro-inflammatory to anti-inflammatory cytokines (p < 0.001). Mediation analyses indicated increased GPR15 expression accounted for roughly half of the relationship between smoking variables and pro-inflammatory to anti-inflammatory cytokine balance. CRP was not associated with cannabis or tobacco use or GPR15+ expression, but was associated with body mass index (p < 0.001). These relationships persisted after controlling for lifestyle and medical factors impacting immune function.

CONCLUSIONS

Increased expression of GPR15 by helper T cells in smokers may mediate some of the relationship between smoking and a pro-inflammatory cytokine milieu. Better understanding of this relationship may help uncover how smoking increases the risk of inflammatory diseases.

Therapeutic Lowering of C-Reactive Protein

In the blood of healthy individuals C-reactive protein (CRP) is typically quite scarce, whereas its blood concentration can rise robustly and rapidly in response to tissue damage and inflammation associated with trauma and infectious and non-infectious diseases. Consequently, CRP plasma or serum levels are routinely monitored in inpatients to gauge the severity of their initial illness and injury and their subsequent response to therapy and return to health. Its clinical utility as a faithful barometer of inflammation notwithstanding, it is often wrongly concluded that the biological actions of CRP (whatever they may be) are manifested only when blood CRP is elevated. In fact over the last decades, studies done in humans and animals (e.g. human CRP transgenic and CRP knockout mice) have shown that CRP is an important mediator of biological activities even in the absence of significant blood elevation, i.e. even at baseline levels. In this review we briefly recap the history of CRP, including a description of its discovery, early clinical use, and biosynthesis at baseline and during the acute phase response. Next we overview evidence that we and others have generated using animal models of arthritis, neointimal hyperplasia, and acute kidney injury that baseline CRP exerts important biological effects. In closing we discuss the possibility that therapeutic lowering of baseline CRP might be a useful way to treat certain diseases, including cancer.

Retinal and Choroidal Thickness in relation to C-Reactive Protein on Swept-Source Optical Coherence Tomography

Purpose

To evaluate the relationships between C-reactive protein (CRP) and retinal and choroidal thickness by swept-source optical coherence tomography (SS-OCT).

Methods

The participants included in the prospective cross-sectional study underwent a comprehensive ophthalmic examination. Based on the CRP values, the subjects were divided into the CRP (+) group (CRP ≥ 8.2 mg/L) and the CRP (−) group (CRP < 8.2 mg/L). The retinal and choroidal thickness was compared between the two groups.

Results

This study enrolled 43 right eyes of 43 subjects from the CRP (+) group and 86 right eyes of 86 gender- and age-match subjects from the CRP (−) group. The choroidal thickness in the CRP (+) group was thinner than that in the CRP (−) group except for the outer nasal sector of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. However, the retinal thickness only in the inner temporal sector showed a significant difference. According to Pearson's correlation analysis, the CRP was significantly negatively correlated with the choroidal thickness in all sectors and the retinal thickness only in the inner temporal and outer nasal sectors of the ETDRS grid.

Conclusion

CRP levels are associated with retinal and choroidal thickness. The data related to the retinal and choroidal thickness changes may help understand the pathogenesis of specific ocular abnormalities in patients with systemic inflammation.

Long period grating in double cladding fiber coated with graphene oxide as high-performance optical platform for biosensing

In this work, the development and testing of a novel fiber-optic based label-free biosensor is presented, whose performance were verified through the detection of C-reactive protein (CRP) in serum. The device is based on a long period grating fabricated in a double cladding fiber with a W-shaped refractive index (RI) profile. As a result, the working point of the device was tuned to the mode transition region by chemical etching of the outer fiber cladding, obtaining a significant enhancement of the RI sensitivity and an excellent visibility of the grating resonances due to the mode transition in an all-silica structure. The fiber transducer was coated with a nanometric thin layer of graphene oxide in order to provide functional groups for the covalent immobilization of the biological recognition element. A very low limit of detection of about 0.15 ng/mL was obtained during the detection of CRP in serum, and a large working range (1 ng/mL - 100 μg/mL) of clinical relevance has been also achieved.

Association analysis of GH1 and CRP loci polymorphisms with reproductive traits in native Pulawska gilts and sows

The objective of the study was to analyse the association of growth hormone (GH1) and C-reactive protein (CRP) loci polymorphisms with reproductive traits in native Pulawska gilts and sows. In the GH1 locus, two mutations were identified: one in the second intron [single-nucleotide polymorphism (SNP) = rs340429823 in.742C>T, MspI], and one in the second exon (SNP = rs340087546 c.566G>A, HaeII). In the CRP locus, two mutations were found in exon 2 (SNP = rs340175625, NM_213844.2: c.1271A>G, BstNI; and SNP = rs80928546, NM_213844.2: c.788C>T, HinfI). Analysis of sexual activity showed that intensity of external estrus signs differed significantly (P ≤ 0.05) and was the most manifested in gilts with the CT (GH1_MspI) genotype during the second estrus. In case of the CRP gene, statistically significant differences (P ≤ 0.05) were found in terms of the duration of farrowing. The longest farrowings were reported for the GG (CRP_HinfI) and the TT (CRP_BstNI) genotypes and the shortest for the AA (CRP_HinfI) and CC (CRP_BstNI). The most numerous first litters were produced by sows with the AA genotype (CRP_HinfI), with significant differences (P ≤ 0.05) between the AA and GG genotypes. In turn, the CC homozygotes (CRP_BstNI) differed significantly (P ≤ 0.05) in terms of the number of piglets born and reared to day 21 in the second litters compared to the other genotype groups.

Acute e-cig inhalation impacts vascular health: a study in smoking naïve subjects

This study was designed to investigate the acute effects of nonnicotinized e-cigarette (e-cig) aerosol inhalation in nonsmokers both in terms of blood-based markers of inflammation and oxidative stress and evaluate their association with hemodynamic-metabolic MRI parameters quantifying peripheral vascular reactivity, cerebrovascular reactivity, and aortic stiffness. Thirty-one healthy nonsmokers were subjected to two blood draws and two identical MRI protocols, each one before and after a standardized e-cig vaping session. After vaping, the serum levels of C-reactive protein, soluble intercellular adhesion molecule, and the danger signal machinery high-mobility group box 1 (HMGB1) and its downstream effector and the NLR family pyrin domain containing 3 (NLRP3) inflammasome (as monitored by its adaptor protein ASC) increased significantly relative to the respective baseline (prevaping) values. Moreover, nitric oxide metabolites and reactive oxygen species production decreased and increased, respectively. These observations were paralleled by impaired peripheral vascular reactivity (with reduced flow-mediated dilation and attenuated hyperemic response after a cuff-occlusion test) and metabolic alterations expressed by decreased venous oxygen saturation, postvaping. The current results suggest propagation of inflammation signaling via activation of the danger signaling axis (HMGB1-NLRP3). The findings indicate that a single episode of vaping has adverse impacts on vascular inflammation and function.NEW & NOTWORTHY Endothelial cell signaling and blood biomarkers were found to correlate with functional vascular changes in a single episode e-cigarettes inhalation in healthy adults. This is indicative of the potential of e-cigarettes (even when inhaled acutely) to lead of vascular dysfunction.

Genetic parameters and associated genomic regions for global immunocompetence and other health-related traits in pigs

The inclusion of health-related traits, or functionally associated genetic markers, in pig breeding programs could contribute to produce more robust and disease resistant animals. The aim of the present work was to study the genetic determinism and genomic regions associated to global immunocompetence and health in a Duroc pig population. For this purpose, a set of 30 health-related traits covering immune (mainly innate), haematological, and stress parameters were measured in 432 healthy Duroc piglets aged 8 weeks. Moderate to high heritabilities were obtained for most traits and significant genetic correlations among them were observed. A genome wide association study pointed out 31 significantly associated SNPs at whole-genome level, located in six chromosomal regions on pig chromosomes SSC4, SSC6, SSC17 and SSCX, for IgG, γδ T-cells, C-reactive protein, lymphocytes phagocytic capacity, total number of lymphocytes, mean corpuscular volume and mean corpuscular haemoglobin. A total of 16 promising functionally-related candidate genes, including CRP, NFATC2, PRDX1, SLA, ST3GAL1, and VPS4A, have been proposed to explain the variation of immune and haematological traits. Our results enhance the knowledge of the genetic control of traits related with immunity and support the possibility of applying effective selection programs to improve immunocompetence in pigs.

Reduction in hsCRP levels is associated with decreased incidence of cardiovascular events in Japanese hypertensive women but not in men

To test our hypothesis that the magnitude of reduction in hsCRP achieved by antihypertensive medications may predict the benefit for cardiovascular outcomes in hypertensive individuals, we performed subanalysis of the ATTEMPT-CVD study. The hypertensive participants enrolled in the ATTMEPT-CVD study were categorized into two groups according to whether achieved reduction in hsCRP levels at 6 months after initiation of antihypertensive medications from baseline was equal to or greater than 40% (responder group) or less than 40% (non-responder group). Baseline characteristics and blood pressure during follow-up period were similar between the groups. For women, the incidence of cardiovascular events was significantly less in responder group than non-responder group (P < 0.0221). However, for men, there was no significant difference between the groups regarding incident cardiovascular events (P = 0.2434). There was a significant interaction (P = 0.0187) between sexes for incident cardiovascular events. Our results provide the evidence suggesting that substantial reduction (40% or greater reduction) in hsCRP on antihypertensive medication predicts the benefit for cardiovascular outcomes in hypertensive women but it does not in hypertensive men. The magnitude of achieved reduction in hsCRP by antihypertensive medications seems to be a useful indicator of successful treatment in Japanese hypertensive women.

This trial was registered with ClinicalTrials.gov, number NCT01075698.

How C-Reactive Protein Structural Isoforms With Distinctive Bioactivities Affect Disease Progression

C-reactive protein (CRP) is a widely known, hepatically synthesized protein whose blood levels change rapidly and pronouncedly in response to any tissue damaging event associated with an inflammatory response. The synthesis and secretion of CRP is stimulated by interleukin-6, an early pleiotropic cytokine released by macrophages, endothelial, and other cells that are activated when localized normal tissue structures are compromised by trauma or disease. Serum CRP levels can change rapidly and robustly from 10-100-fold within 6–72 h of any tissue damaging event. Elevated blood levels correlate with the onset and extent of both activated inflammation and the acute phase biochemical response to the tissue insult. Because its functional bioactivity as the prototypic acute phase reactant has eluded clear definition for decades, diagnosticians of various conditions and diseases use CRP blood levels as a simple index for ongoing inflammation. In many pathologies, which involves many different tissues, stages of disease, treatments, and responses to treatments, its interpretive diagnostic value requires a deeper understanding of the localized tissue processes and events that contribute signals which regulate protective or pathological host defense bioactivities. This report presents concepts that describe how local tissue activation events can lead to a non-proteolytic, conformational rearrangement of CRP into a unique isoform with distinctive solubility, antigenicity, binding reactivities and bioactivities from that protein widely known and measured in serum. By describing factors that control the expression, tissue localization, half-life and pro-inflammatory amplification activity of this CRP isoform, a unifying explanation for the diagnostic significance of CRP measurement in disease is advanced.

Interplay between the Mediterranean diet and C-reactive protein genetic polymorphisms towards inflammation in adolescents

AIM

From a nutrigenetics perspective, we aim to investigate the moderating role of the Mediterranean diet and each of its subgroups in the association between C-reactive protein (CRP) gene polymorphisms and CRP blood concentration in adolescents.

METHODS

In 562 adolescents (13-17 y) of the European HELENA study, data was available on circulating CRP levels as inflammatory biomarker, three CRP gene SNPs (rs3093068, rs1204, rs1130864), food intake determined by a self-administered computerized 24 h-dietary recall for 2 days, and body composition. A 9-point Mediterranean diet score and each food subgroup were tested as moderator via SNP*diet interaction. Analyzes were adjusted for age, sex, puberty, adiposity and socioeconomic status.

RESULTS

The minor allele frequencies of rs3093068 and rs1130864 SNPs (GG and TT, respectively) were associated with higher CRP concentrations, while rs1205 (CT/TT) was associated with lower CRP concentrations. There were significant interactions between rs3093068 and Mediterranean diet (B = -0.1139, p = 0.011), or the fish food subgroup (B = -0.0090, p = 0.022), so that those with the highest genetic CRP risk underwent the highest CRP attenuation by a healthier diet. Although the effect of diet and SNP was substantial, the explained variance by interaction was only 1%.

CONCLUSION

Greater adherence to the Mediterranean diet and particularly its fish component was associated with a lower CRP blood concentrations especially in those at highest genetic risk due to the rs3093068 SNP.

C-reactive protein gene rs1205 polymorphism is associated with low-grade chronic inflammation in postmenopausal women

Background

Cardiovascular disease is the leading cause of death in postmenopausal women, and inflammation is a key mechanism involved in the pathogenesis of atherosclerosis. High-sensitivity C-reactive protein (hs-CRP) has been used as a biomarker of inflammation. Considering that CRP gene rs1205 polymorphism has been associated with hs-CRP circulating levels, we evaluated whether rs1205 genotypes influence the presence of low-grade chronic inflammation, acting as a marker of cardiovascular risk.

Methods

We performed a cross-sectional study with biobanked blood samples from 327 postmenopausal women with no evidence of clinical disease. Genotyping for rs1205 C > T SNP of the CRP gene was done by real-time polymerase chain reaction with allelic discrimination assays.

Results

Mean age was 55.6 ± 5.6 years. Mean body mass index (BMI) was 27.3 ± 4.7. Participants were divided according to hs-CRP levels: ≥3 mg/l (low-grade chronic inflammation) or < 3 mg/l. The frequency of allele C at rs1205 was 74.2% in the hs-CRP ≥ 3 mg/l group vs. 59% in the hs-CRP < 3 mg/l. In a multivariable model, higher prevalence of hs-CRP ≥ 3 mg/l was associated with CC genotype (PR 1.53; 95%CI 1.07-2.18; p = 0.018) and waist circumference ≥ 88 cm (PR 2.45; 95%CI 1.66-3.60; p < 0.001).

Conclusions

CRP rs1205 CC homozygotes may be at higher risk of a low-grade chronic inflammatory status compared to individuals carrying the T allele.

A large-scale genetic correlation scan identified the plasma proteins associated with brain function related traits

AIMS

Insomnia, intelligence and neuroticism are three typical traits and dysfunctions mainly regulated by human brain. Our research aimed to explore the potential genetic relationships between brain function related traits and more than 3000 human plasma proteins.

MATERIALS AND METHODS

We conducted a large-scale genetic correlation scan of human plasma proteins and three brain function related traits, including insomnia, intelligence and neuroticism. Linkage disequilibrium score regression (LDSC) analysis was performed to estimate the genetic correlations between each of the blood proteins and insomnia, intelligence and neuroticism via utilizing the genome-wide association study summary statistics of plasma proteins and those three traits.

RESULTS

LDSC analysis identified 18 specific plasma proteins shown suggestive genetic correlations with insomnia such as Periostin (coefficient=-0.3910, P value = 0.0070). Twenty-one plasma proteins exhibited genetic correlations with intelligence such as Ecto-ADP-ribosyltransferase 3 (coefficient = 0.3066, P value = 0.0013). Six specific plasma proteins shown suggestive genetic correlations with neuroticism, such as CD70 antigen (coefficient = 0.2979, P value = 0.0134). After further comparing the suggestive proteins between insomnia, intelligence and neuroticism, we detected 3 common plasma proteins shared by insomnia and intelligence such as Periostin (coefficient _insomnia =-0.3910, P_insomnia value = 0.0070; coefficient _intelligence =0.2673, P_intelligence value = 0.0159) and Neurexin-1 (coefficient _insomnia =-0.2913, P_insomnia value = 0.0197; coefficient _intelligence = 0.2399, P_intelligence value = 0.0035). We also detected 2 common plasma proteins shared by intelligence and neuroticism, including CD70 antigen (coefficient _intelligence =-0.2092, P_intelligence value = 0.0337; coefficient _neuroticism = 0.2979, P_neuroticism value = 0.0134).

CONCLUSION

Our results provide novel clues for unveiling the functional relevance of plasma proteins and brain function related traits.

Macrophages in xenotransplantation

Xenotransplantation refers to organ transplantation across species. Immune rejection of xenografts is stronger and faster than that of allografts because of significant molecular differences between species. Recent studies have revealed the involvement of macrophages in xenograft and allograft rejections. Macrophages have been shown to play a critical role in inflammation, coagulation, and phagocytosis in xenograft rejection. This review presents a recent understanding of the role of macrophages in xenograft rejection and possible strategies to control macrophage-mediated xenograft rejection.

Monomeric C-reactive protein regulates fibronectin mediated monocyte adhesion

The acute phase reactant C-reactive protein (CRP) binds with high affinity to fibronectin (FN), but this binding occurs only at pH 6.5 or lower, and the binding is inhibited by calcium ions at physiological pH. Since CRP in the circulating blood exists in a calcium-binding form, the interaction between CRP and FN in vivo has been uncertain. CRP can undergo a conformational rearrangement in the absence of calcium or in the local microenvironment (e.g., acidic pH) of inflamed tissue to dissociate into monomeric CRP (mCRP). Therefore, we tested whether these discrepancies can be explained by the different isoforms and locations of CRP. Surface plasmon resonance and ELISA assays showed that mCRP binds with high affinity to FN, and the binding of mCRP to FN was unaffected by calcium or pH. Peptide competition assay, deletion mutant binding assay and protein docking analyse verified that the binding site of mCRP to FN is residues a.a.35-47. Furthermore, mCRP can significantly enhance the adhesion of monocytes to FN as well as upregulate the adhesion molecules expression on endothelial cell. Colocalization of mCRP with FN was observed in mice with DSS-induced colitis, whereas there was very little signal orcolocalization of CRP. These results provide in vitro and in vivo evidence that mCRP formed by local dissociation from circulating CRP is the major isoform that interacts with FN and regulates FN-mediated monocyte adhesion, which is involved in the pro-inflammatory process.

Impact of C-reactive protein on osteo-/chondrogenic transdifferentiation and calcification of vascular smooth muscle cells

Medial vascular calcification occurs during the aging process and is strongly accelerated by chronic kidney disease (CKD). Elevated C-reactive protein (CRP) levels are associated with vascular calcification, cardiovascular events and mortality in CKD patients. CRP is an important promoter of vascular inflammation. Inflammatory processes are critically involved in initiation and progression of vascular calcification. Thus, the present study explored a possible impact of CRP on vascular calcification. We found that CRP promoted osteo-/chondrogenic transdifferentiation and aggravated phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of primary human aortic smooth muscle cells (HAoSMCs). These effects were paralleled by increased cellular oxidative stress and corresponding pro-calcific downstream-signaling. Antioxidants or p38 MAPK inhibition suppressed CRP-induced osteo-/chondrogenic signaling and mineralization. Furthermore, silencing of Fc fragment of IgG receptor IIa (FCGR2A) blunted the pro-calcific effects of CRP. Vascular CRP expression was increased in the klotho-hypomorphic mouse model of aging as well as in HAoSMCs during calcifying conditions. In conclusion, CRP augments osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells through mechanisms involving FCGR2A-dependent induction of oxidative stress. Thus, systemic inflammation may actively contribute to the progression of vascular calcification.

Low-grade inflammation is negatively associated with physical Health-Related Quality of Life in healthy individuals: Results from The Danish Blood Donor Study (DBDS)

Background

Health-Related Quality of Life (HRQL) represent individuals’ subjective assessment of their mental and physical well-being, and is highly predictive of future health. C-reactive protein (CRP) is a well-established marker of inflammation. Low-grade inflammation (LGI), defined as slightly increased CRP levels, is associated with increased risk of several diseases. LGI may reflect subclinical pathology, which could affect individual’s subjective health assessment. This study aimed to examine whether LGI has an independent impact on self-reported health or rather is a mediator of a confounder in a large population of healthy individuals.

Methods

Plasma CRP levels were measured in 17,024 participants from the Danish Blood Donor Study (DBDS). All participants completed a standard questionnaire including smoking status, and the 12-item short-form health survey (SF-12), which is a widely used scale for HRQL. SF-12 is reported as a mental (MCS) and physical (PCS) score. The relationship between LGI (defined as a plasma CRP level between 3 mg/L and 10 mg/L) and MCS or PCS was explored by mediation analysis and adjusted multivariable linear regression analysis. Multiple imputation modelling was used to remedy missing values. The analyses were stratified according to sex and use of combined oral contraception (OC).

Results

In the study, 1,542 (10.3%) participants had LGI. PCS was associated with LGI in all strata, i.e. women using OC: RC = -0.36 points lower PCS in participants with LGI vs no LGI, CI: -0.94 to -0.19, women not using OC: RC = -0.63, CI: -1.05 to -0.21 and men: RC = -0.76, CI: -1.10 to -0.42. But LGI had no impact on MCS. Predictors of lower PCS included obesity, current smoking, and waist circumference in all strata. Physical activity in leisure time was the only factor positively associated with PCS. Age and physical activity in leisure time was associated with increased MCS in all strata whereas current smoking was the only strong predictor of a reduction in MCS. Only a small effect of smoking on PCS was mediated through LGI.

Conclusion

In this population of healthy individuals, LGI had independent impact on lower self-rated physical health score in HRQL in both sexes, but was not associated with self-rated mental health score. A small and significant effect of smoking on physical health score was mediated through LGI.