Plasma soluble gp130 levels are increased in older subjects with metabolic syndrome. The role of insulin resistance.
OBJECTIVE
Increased interleukin-6 plasma levels have been reported in metabolic syndrome (MS); nevertheless, it is unclear whether interleukin-6 activity is exerted through direct signalling only or also through the "trans-signalling". This issue is important to clarify since signalling and "trans-signalling" affect different tissues. We investigated the relationship between MS and the interleukin-6 system in an older population.


METHODS
Data from 997 older community dwelling individuals (age ≥ 65 years; females: 56.2%) enrolled the InChianti study were analysed. Interleukin-6, soluble interleukin-6 receptor (sIL-6r), and soluble glycoprotein 130 (sgp130) were measured on plasma by ELISA. MS was defined by the NCEP ATP III criteria; 309 individuals (31%) resulted affected by MS.


RESULTS
Subjects with MS had higher interleukin-6 and sgp130 levels compared to controls; a trend toward higher levels of sIL-6R was also observed. The risk of having MS was increased in individuals with high sIL-6r or/and sgp130 levels, independent of age, gender, and interleukin-6 levels. Elevated sgp130 levels were associated with higher plasma glucose, HOMA, triglycerides, and with diabetes both in subjects with and without MS. Although the risk of high sgp130 levels was generally associated with MS (O.R.: 1.77, 95%C.I.: 1.39-2.25), this excess of risk was not present in MS phenotypes excluding the criteria "elevated glucose" or "elevated triglycerides". Furthermore, the association between sgp130 and MS disappeared after adjustment for HOMA.


CONCLUSIONS
We found that older individuals with MS have increased sgp130 plasma levels compared with controls; nevertheless, our data suggest that this association might be mediated by insulin resistance.
Zuliani
Giovanni
G
Department of Clinical and Experimental Medicine, Section of Internal Medicine, Gerontology & Geriatrics, University of Ferrara, Via Savonarola no 9, 44100 Ferrara, Italy. gzuliani@hotmail.com
Galvani
Matteo
M
Maggio
Marcello
M
Volpato
Stefano
S
Bandinelli
Stefania
S
Corsi
Anna Maria
AM
Lauretani
Fulvio
F
Cherubini
Antonio
A
Guralnik
Jack M
JM
Fellin
Renato
R
Ferrucci
Luigi
L
D000368:Aged; D000375:Aging; D050822:Cytokine Receptor gp130 / Q000097:blood*; D004032:Diet; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation; D007333:Insulin Resistance; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D019947:Receptors, Interleukin-6 / Q000378:metabolism; D015398:Signal Transduction
D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D050822:Cytokine Receptor gp130