Serum galectin-3 is elevated in obesity and negatively correlates with glycosylated hemoglobin in type 2 diabetes.
BACKGROUND
Adipocytes synthesize galectin-3 whose deficiency protects from inflammation associated with metabolic diseases. We aimed to study circulating galectin-3 in obesity and type 2 diabetes (T2D).


METHODS
Galectin-3 was measured by ELISA in the serum of male normal-weight and overweight controls and T2D patients and in T2D patients of both sexes. Because visceral fat contributes to systemic inflammation, galectin-3 was analyzed in paired samples of human and rodent sc and visceral adipose tissue. Visceral adipose tissue adipokines are released to the portal vein, and galectin-3 was analyzed in portal, hepatic, and systemic venous serum (PVS, HVS, and SVS, respectively) of patients with liver cirrhosis and in patients who underwent surgery for nonhepatic diseases. The effect of metformin on adipocyte galectin-3 was analyzed by immunoblot.


RESULTS
Circulating galectin-3 was similarly elevated in T2D and obesity compared with normal-weight individuals and revealed a body mass index-dependent positive correlation with leptin, resistin, IL-6, and age. In T2D patients, galectin-3 was increased in serum of patients with elevated C-reactive protein and negatively correlated with glycated hemoglobin. Metformin treatment was associated with lower systemic galectin-3. Reduced galectin-3 in metformin-incubated human adipocytes indicated that low galectin-3 may be a direct effect of this drug. Galectin-3 was higher in PVS compared with HVS and SVS, suggesting that the splanchnic region is a major site of galectin-3 synthesis. Low galectin-3 in HVS compared with PVS demonstrated hepatic removal.


CONCLUSIONS
Systemic galectin-3 is elevated in obesity and negatively correlates with glycated hemoglobin in T2D patients, pointing to a modifying function of galectin-3 in human metabolic diseases.
Weigert
Johanna
J
Department of Internal Medicine I, Regensburg University Hospital, D-93042 Regensburg, Germany.
Neumeier
Markus
M
Wanninger
Josef
J
Bauer
Sabrina
S
Farkas
Stefan
S
Scherer
Marcus N
MN
Schnitzbauer
Andreas
A
Schäffler
Andreas
A
Aslanidis
Charalampos
C
Schölmerich
Jürgen
J
Buechler
Christa
C
D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000328:Adult; D000368:Aged; D000818:Animals; D015153:Blotting, Western; D015992:Body Mass Index; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D037502:Galectin 3 / Q000378:metabolism*; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D050152:Intra-Abdominal Fat / Q000187:drug effects / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008297:Male; D008687:Metformin / Q000494:pharmacology / Q000627:therapeutic use; D051379:Mice; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D052243:Resistin / Q000097:blood; D018709:Statistics, Nonparametric
D037502:Galectin 3; D006442:Glycated Hemoglobin; D020738:Leptin; D008687:Metformin; D052243:Resistin