A specific immunophenotype and an increased adipogenic potential characterized human amniotic mesenchymal stem cells (hA-MSCs) isolated from obese pregnant women at delivery

Maternal obesity is associated to increased fetal risk of obesity and other metabolic diseases. Human amniotic mesenchymal stem cells (hA-MSC) have not been characterized in obese women. The aim of this study was to isolate and compare hA-MSC immunophenotypes from obese (Ob-) and normal weight control (Co-) women to identify alterations possibly predisposing the foetus to obesity. We enrolled 16 Ob- and 7 Co-women at delivery (mean/SEM pre-pregnancy BMI: 40.3/1.8 kg/m2 and 22.4/1.0 kg/m2, respectively). hA-MSCs were phenotyped by flow cytometry; several maternal and newborn clinical and biochemical parameters were also measured. The expression of membrane antigen CD13 was higher on Ob-hA-MSCs than on Co-hA-MSCs (P=0.0043). Also serum levels of CD13 at delivery were higher in Ob- versus Co-pregnant women and correlated with CD13 antigen expression on Ob-hA-MSCs (r2=0.84, P<0.0001). Adipogenesis induction experiments revealed that Ob-hA-MSCs had a higher adipogenic potential than Co-hA-MSCs as witnessed by higher PPARg and aP2 mRNA levels (P=0.02 and P=0.03, respectively) at post-induction day 14 associated with an increase of CD13 mRNA from baseline to day 4 post-induction (P<0.05). Adipogenesis was similar in the two sets of hA-MSCs after CD13 silencing, whereas it was increased in Co-hA-MSCs after CD13 overexpression. Pretreatment of Co- and Ob-hA-MSCs with IFN-g ng/mL) for 24 h induced upregulation of CD13 expression. In conclusion, antigen CD13, by influencing the adipogenic potential of hA-MSCs could be an in-utero risk factor for obesity. Our data strengthen the hypothesis that high levels of serum and MSC CD13 are obesity markers.