title: Adiposity and immune-muscle crosstalk in South Asians &Europeans: A cross-sectional study.
abstract: 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 μm(2) versus 0.15 ± 0.06 μm(2), 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.
authors.affiliation: Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.|Division of Pediatric Endocrinology, McMaster Children's Hospital, Hamilton, Ontario, Canada.
authors.forename: M Constantine
authors.initials: MC
authors.lastname: Samaan
authors.affiliation: Population Genomics Program, Chanchlani Research Centre, McMaster University, Hamilton, ON, Canada.|Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, Ontario, Canada.|Department of Medicine, McMaster University, Hamilton, Ontario, Canada.|Department of Clinical Epidemiology/Biostatistics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Anand
authors.affiliation: University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Arya M
authors.initials: AM
authors.lastname: Sharma
authors.affiliation: Department of Clinical Epidemiology/Biostatistics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Ashley
authors.initials: A
authors.lastname: Bonner
authors.affiliation: Department of Clinical Epidemiology/Biostatistics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Joseph
authors.initials: J
authors.lastname: Beyene
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Imtiaz
authors.initials: I
authors.lastname: Samjoo
authors.affiliation: Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.|Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics / Q000276:immunology; D044466:Asian People; D001692:Biological Transport; D001823:Body Composition; D015992:Body Mass Index; D002170:Canada; D018932:Chemokine CCL2 / Q000235:genetics* / Q000276:immunology; D003430:Cross-Sectional Studies; D005227:Fatty Acids / Q000276:immunology / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D050152:Intra-Abdominal Fat / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008099:Liver / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009765:Obesity / Q000208:ethnology* / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D062606:Tertiary Care Centers; D044465:White People; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018932:Chemokine CCL2; D005227:Fatty Acids; C111835:CCL2 protein, human; C067980:CD68 antigen, human; D000097382:CD68 Molecule