ABSTRACT
Genetic susceptibility has been described in insulin resistance (IR). Chemokine (C-C motif) ligand-2 (CCL2) is overexpressed in white adipose tissue and is the ligand of C-C motif receptor-2 (CCR2). The CCL2 G-2518A polymorphism is known to regulate gene expression, whereas the physiological effects of the CCR2Val64Ile polymorphism are unknown. The aim of the study is to investigate the relationship between these polymorphisms with soluble CCL2 levels (sCCL2), metabolic markers, and adiposity. In a cross-sectional study we included 380 Mexican-Mestizo individuals, classified with IR according to Stern criteria. Polymorphism was identified using PCR-RFLP/sequence-specific primers. Anthropometrics and metabolic markers were measured by routine methods and adipokines and sCCL2 by ELISA. The CCL2 polymorphism was associated with IR (polymorphic A+ phenotype frequencies were 70.9%, 82.6%, in individuals with and without IR, resp.). Phenotype carriers CCL2 (A+) displayed lower body mass and fat indexes, insulin and HOMA-IR, and higher adiponectin levels. Individuals with IR presented higher sCCL2 compared to individuals without IR and was associated with CCR2 (Ile+) phenotype. The double-polymorphic phenotype carriers (A+/Ile+) exhibited higher sCCL2 than double-wild-type phenotype carriers (A-/Ile-). The present findings suggest that sCCL2 production possibly will be associated with the adiposity and polymorphic phenotypes of CCL2 and CCR2, in Mexican-Mestizos with IR.
Subject(s)
Adiposity , Chemokine CCL2/blood , Insulin Resistance/ethnology , Polymorphism, Genetic , Receptors, CCR2/blood , Adult , Aged , Anthropometry , Chemokine CCL2/genetics , Cross-Sectional Studies , Enzyme-Linked Immunosorbent Assay , Female , Genetic Association Studies , Humans , Insulin Resistance/genetics , Male , Mexico , Middle Aged , Obesity/ethnology , Obesity/genetics , Phenotype , Polymorphism, Restriction Fragment Length , Polymorphism, Single Nucleotide , Receptors, CCR2/genetics , Young AdultABSTRACT
RATIONALE: Sepsis is defined as a systemic inflammatory response to infection, which in its severe form is associated with multiple organ dysfunction syndrome (MODS). The precise mechanisms by which MODS develops remain unclear. Neutrophils have a pivotal role in the defense against infections; however, overwhelming activation of neutrophils is known to elicit tissue damage. OBJECTIVES: We investigated the role of the chemokine receptor CCR2 in driving neutrophil infiltration and eliciting tissue damage in remote organs during sepsis. METHODS: Sepsis was induced in wild-type mice treated with CCR2 antagonist (RS504393) or CCR2(-/-) mice by cecal ligation and puncture (CLP) model. Neutrophil infiltration into the organs was measured by myeloperoxidase activity and fluorescence-activated cell sorter. CCR2 expression and chemotaxis were determined in neutrophils stimulated with Toll-like receptor agonists or isolated from septic mice and patients. MEASUREMENTS AND MAIN RESULTS: CCR2 expression and responsiveness to its ligands was induced in circulating neutrophils during CLP-induced sepsis by a mechanism dependent on Toll-like receptor/nuclear factor-κB pathway. Genetic or pharmacologic inhibition of CCR2 protected mice from CLP-induced mortality. This protection was associated with lower infiltration of neutrophils into the lungs, heart, and kidneys and reduced serum biochemical indicators of organ injury and dysfunction. Importantly, neutrophils from septic patients express high levels of CCR2, and the severity of patient illness correlated positively with increasing neutrophil chemotaxis to CCR2 ligands. CONCLUSIONS: Collectively, these data identify CCR2 as a key receptor that drives the inappropriate infiltration of neutrophils into remote organs during sepsis. Therefore, CCR2 blockade is a novel potential therapeutic target for treatment of sepsis-induced MODS.
Subject(s)
Multiple Organ Failure/blood , Neutrophils/metabolism , Receptors, CCR2/blood , Shock, Septic/blood , Animals , Biomarkers/blood , Chemotaxis , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay/methods , Flow Cytometry/methods , Humans , Mice , Mice, Inbred C57BL , Multiple Organ Failure/etiology , Peroxidase/blood , Severity of Illness Index , Shock, Septic/complications , Up-RegulationABSTRACT
In this study, the expression of chemokine receptors on the surface of circulating leukocytes was determined using flow cytometry. An increase in the percentage of CCR2+CD4+ lymphocytes was observed in the peripheral blood of leprosy patients. This preliminary data suggests that alterations occur in the chemokine receptor profile of these patients.