Session: SUN-LB-Late-Breaking Poster Session 2
Bench to Bedside
Poster Board SUN-LB-02
Li Fen Liu, John Morton, Homer Rivas, Colleen M Craig, Lorna L. Tolentino, Sam Cushman, Edgar G Engleman, Tracey McLaughlin
Objective: Pro-inflammatory immune cell infiltration in human adipose tissues is associated with obesity and insulin resistance. Impaired adipocyte differentiation may also contribute to insulin resistance, but factors determining adipogenic potential are unclear. The aim of the current study was to investigate whether CD14+ leukocytes play a role in adipocyte differentiation by culturing human preadipocytes in the presence or absence of CD14+ cells. Methods: Abdominal subcutaneous (SAT) and omental adipose tissues (VAT) were obtained from five subjects undergoing bariatric surgery. CD14+ leukocytes were removed by immune magnetic separation from the stromal-vascular cell fraction isolated from SAT and VAT via collagenase digestion. Preadipocytes isolated from SAT and VAT were either cultured in the presence of CD14+ cells, by adding back 10% of CD14+ cells, or in the absence of CD14 cells.
CD14+ and CD14- co-cultured of SAT and VAT preadipocytes were differentiated into adipocytes in vitro for 14 days after cells were confluent. Adipocyte differentiation was quantified via immunostaining on day 14. The percentage of differentiated adipocytes was defined as Bodipy+ cells/dapi+ cells, averaged over four fields.
Results: Adipocyte differentiation was significantly lower in VAT as compared with SAT (9.4±6.0% vs 30.4±14.1 %, p<0.05). Frequency of CD14+ cells ranged between 6.99 and 21.2% in SAT, whereas the frequency of CD14 ranged between 15 and 33% in VAT and was NS different between depots. The percentage of differentiated human adipocytes from SAT was significantly lower in CD14+ culture vs CD14- culture (16.3 ± 9.7 vs 30.4 ± 14.1%, p<0.03), whereas the percentage of differentiated adipocytes from VAT did not differ according to presence of CD14+ cells (CD14+ 8.1± 5.7 vs CD14- 9.4 ± 6) .
Conclusions: Our data demonstrate impaired adipocyte differentiation in VAT. Further, they demonstrate that the presence of CD14 leukocytes in SAT significantly impairs adipocyte differentiation. This effect does not appear to be present in VAT, in which differentiation was poor irrespective of presence of CD14+ cells. Together these data suggest that inflammatory cells in human SAT impair adipocyte differentiation, which may link both processes to insulin resistance.
Nothing to Disclose: LFL, JMM, HR, CMC, LLT, EGE, TLM, SWC
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