Association of monocyte chemoattractant protein-1 -2518 polymorphism with metabolic syndrome in a South Indian cohort

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Adiposity and immune-muscle crosstalk in South Asians &Europeans: A cross-sectional study

South Asians (SA) are at higher risk of cardiometabolic disorders than Europeans (EU), yet the potential determinants of this risk are poorly understood. We tested the hypotheses that 1) South Asians (SA) have greater muscle inflammation compared to Europeans (EU) at similar fat mass 2) differential regional adiposity in SA compared to EU is associated with enhanced muscle inflammation in SA. This cross-sectional study was conducted at a tertiary academic center in Hamilton, Ontario, Canada. The study included 29 EU and 26 SA. Quantitative real-time PCR and western blot were used to measure muscle inflammation. Statistical analysis was done using a General Linear Model. Despite having similar macrophage content to EU, SA muscle had lower levels of chemokine CCL2 compared to EU at gene expression (β -1.099, SE β 0.521, p-value 0.04) and protein (0.84 ± 0.69 versus 1.10 ± 0.60, p-value 0.052) levels. SA had more pronounced abdominal and hepatic adiposity, with smaller Intramyocellular lipid particles compared to EU (0.26 ± 0.12 μm² versus 0.15 ± 0.06 μm², p-value 0.02). In conclusion, CCL2 downregulation in SA may be an attempt to protect muscle against macrophage infiltration, and defects in fatty acid partitioning to muscle may lead to the disproportionate adiposity and adverse cardiometabolic profile in SA.

Gene - Gene Interactions Among MCP Genes Polymorphisms in Asthma

Purpose

Monocyte chemoattractant proteins (MCPs) are important cytokines that involved in cellular activation and releasing of inflammatoy mediators by basophils and eosinophils in allergic disease. Some MCP gene variants implicate in asthma and monoclonal antibody for MCP-3 blocks allergic inflammations in the patients with asthma. Detection of interactions between gene and environment or between genes for complex disease such as asthma is important. We searched for an evidence of genetic effect of single nucleotide polymorphisms (SNPs) of MCP genes as well as gene - gene interactions involved in asthma.

Methods

Four hundreds asthmatics and four hundreds normal controls were enrolled. Asthma was defined as a positive bronchodilator response or positive methacholine provocation test with compatible clinical symptoms. Seven MCP gene SNPs (2 SNPs in MCP-1, 1 in MCP-2, and 4 in MCP-3) were included. Association analyses between SNP and asthma, and the tests for gene - gene interaction were performed.

Results

Strong linkage disequilibria were found among 7 MCP gene polymorphisms. There was no SNP that showed a significant association with asthma among 7 SNPs of 3 MCP genes. No haplotype was associated with asthma, either. The combination of MCP1-2518G>A, MCP2+46A>C, and MCP3+563C>T was the best predictive model for asthma as compared to the control in tests for gene - gene interaction. The MCP1-2518G>A and MCP2+46A>C was the second best predictive combination and this had the highest synergistic interaction effect on the subject's status than any other combination of polymorphisms. Complete linkages were not associated with the gene - gene interactions models.

Conclusions

MCP gene polymorphisms probably interact with each other; thus, these findings may help in developing a possible genetic marker to predict asthma.

Association of adipokines with cardiovascular risk factors in low birth weight children: a case-control study

Our aim was to investigate plasma levels of adiponectin, monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) in low birth weight (LBW) children and to determine correlations among these adipokines and birth weight and cardiovascular disease risk factors. In a case-control study, the concentrations of adiponectin, MCP-1 and PAI-1 were measured in 180 schoolchildren (ages 6-11 years). MCP-1 and PAI-1 levels were significantly elevated in LBW children. Conversely, adiponectin concentration was significantly reduced in these children. Similar findings were observed after adjustment for current age, gender and abdominal circumference. Because the children with LBW had altered adipokine levels, as well as higher abdominal circumference, HOMA-IR and systolic blood pressure (SBP), we evaluated the correlation among these variables. These analyses showed that adiponectin levels were inversely correlated with systolic blood pressure (SBP) (r = -0.501; P < 0.001), HOMA-IR (r = -0.293; P = 0.023) and waist circumference (r = -0.317; P = 0.014). The proinflammatory markers were positively correlated with HOMA-IR (PAI-1: r = 0.358; P = 0.005) and waist circumference (PAI-1: r = 0.571; P < 0.001 and MCP-1: r = 0.267; P = 0.039).

CONCLUSION

Adipokines levels were correlated with cardiovascular risk factors in LBW children, and these compounds could be involved in the mechanism that links birth weight to the development of cardiovascular diseases in adulthood.

The rs1024611 regulatory region polymorphism is associated with CCL2 allelic expression imbalance

CC chemokine ligand 2 (CCL2) is the most potent monocyte chemoattractant and inter-individual differences in its expression level have been associated with genetic variants mapping to the cis-regulatory regions of the gene. An A to G polymorphism in the CCL2 enhancer region at position -2578 (rs1024611; A>G), was found in most studies to be associated with higher serum CCL2 levels and increased susceptibility to a variety of diseases such as HIV-1 associated neurological disorders, tuberculosis, and atherosclerosis. However, the precise mechanism by which rs1024611influences CCL2 expression is not known. To address this knowledge gap, we tested the hypothesis that rs1024611G polymorphism is associated with allelic expression imbalance (AEI) of CCL2. We used haplotype analysis and identified a transcribed SNP in the 3'UTR (rs13900; C>T) can serve as a proxy for the rs1024611 and demonstrated that the rs1024611G allele displayed a perfect linkage disequilibrium with rs13900T allele. Allele-specific transcript quantification in lipopolysaccharide treated PBMCs obtained from heterozygous donors showed that rs13900T allele were expressed at higher levels when compared to rs13900C allele in all the donors examined suggesting that CCL2 is subjected to AEI and that that the allele containing rs1024611G is preferentially transcribed. We also found that AEI of CCL2 is a stable trait and could be detected in newly synthesized RNA. In contrast to these in vivo findings, in vitro assays with haplotype-specific reporter constructs indicated that the haplotype bearing rs1024611G had a lower or similar transcriptional activity when compared to the haplotype containing rs1024611A. This discordance between the in vivo and in vitro expression studies suggests that the CCL2 regulatory region polymorphisms may be functioning in a complex and context-dependent manner. In summary, our studies provide strong functional evidence and a rational explanation for the phenotypic effects of the CCL2 rs1024611G allele.

Variation of serum monocyte chemoattractant protein-1 in patients with diabetes and metabolic syndrome

This study investigated the variation of serum monocyte chemoattractant protein-1 (MCP-1) in patients with both diabetes mellitus (DM) and metabolic syndrome (MS). Based on the International Diabetes Federation (IDF) diagnostic criteria, 93 patients enrolled in this study were divided into four groups: normal control (NC), simple DM, simple MS, and DM plus MS (DM-MS) groups. The main measures included height, weight, waist circumference (WC), hip circumference, blood pressure, fasting blood glucose, insulin resistance index (HOMA-IR), serum triglyceride (TG), HDL-ch, LDL-ch, and MCP-1. The results showed that the serum levels of MCP-1 in the DM-MS group were significantly increased as compared with those in the DM and MS groups (P<0.05), and the increase in the MCP-1 level in the DM group was much higher than in the MS group (P<0.05). The DM-MS group had the highest HOMA-IR levels, followed by MS, DM and NC groups (P<0.05). Correlation tests showed that the association of MCP-1 with age, HDL-ch, or LDL-ch was insignificant, whereas that of MCP-1 with body mass index (BMI), waist hip rate (WHR), WC, systolic blood pressure (SBP), diastolic blood pressure (DBP), TG, and HOMA-IR was significantly positive. It was concluded that circulating MCP-1 was substantially increased in patients with both DM and MS as compared with that in the patients with DM or MS alone, and the central obese state may contribute to a more vicious proinflammatory condition and insulin resistance in patients with diabetes.