Central leptin and insulin administration modulates serum cytokine- and lipoprotein-related markers.
In most obese patients there is an inflammatory state characterized by lipid abnormalities, hyperleptinemia and hyperinsulinemia.


OBJECTIVE
The objective was to identify mechanisms involved in leptin's role in the attenuation of the response to insulin using a proteomic approach.


METHODS
We studied the serum proteomic profile of rats treated by central leptin infusion followed by an injection of insulin. We analyzed the relationship between these proteins and serum cytokine and apolipoprotein levels.


RESULTS
Out of 81 protein spots, intensity differences were found in 11, corresponding to 5 proteins: three isoforms of α1 macroglobulin; three of haptoglobin and serum amyloid P component-precursor. All of these are acute-phase proteins involved in inflammation and are correlated with cytokine levels. Additionally, two apolipoprotein E and two apolipoprotein A1 isoforms were identified and were found to correlate with LDL and HDL.


CONCLUSIONS
Our results indicate that increased leptin and insulin levels change these circulating proteins, thus promoting systemic inflammation and changing lipid metabolism.
Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto Investigación Sanitaria Princesa, Madrid, E-28009 Spain.
Emma
E
Burgos-Ramos
Lucila
L
Sackmann-Sala
Eva
E
Baquedano
Diana
D
Cruz-Topete
Vicente
V
Barrios
Jesús
J
Argente
John J
JJ
Kopchick
D000818:Animals; D001835:Body Weight; D016207:Cytokines / Q000097:blood*; D015180:Electrophoresis, Gel, Two-Dimensional; D004797:Enzyme-Linked Immunosorbent Assay; D007328:Insulin / Q000008:administration & dosage*; D020738:Leptin / Q000008:administration & dosage* / Q000235:genetics; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D016207:Cytokines; D007328:Insulin; D020738:Leptin; D008074:Lipoproteins; D012333:RNA, Messenger