PSUN123 Increased Expression of Insulin Signaling Intermediates After Six-Months Of Medical Care In Women With Obesity And Polycystic Ovary Syndrome
Authors: Akalestou Elina , Andrisse Stanley , Johnson Brett , Miras Alexander Dimitri , O’Donnell Karen , Samarasinghe Suhaniya 
Published: November 2022

Background

Recently an androgen-induced obesity-independent mechanism of insulin resistance in a mouse model mimicking lean polycystic ovary syndrome (PCOS) was discovered. To date there is little to no data on the mechanism of insulin resistance or molecular insulin signaling in adipose tissue of women with PCOS undergoing Vertical Sleeve Gastrectomy (VSG). Does the mechanism of androgen receptor (AR)-mediated regulation of insulin signaling seen in the lean PCOS mouse model occur in adipose tissue of women with obesity and PCOS?

Objective

We hypothesize that in women with obesity and PCOS, those with higher levels of free androgen index will display more dysregulation in the insulin signaling pathway in adipose tissue. More specifically, we believe that visceral more than subcutaneous adipose tissue in the women in the study will display more dysregulation; and lastly that VSG will alleviate insulin signaling dysregulation. Briefly, insulin activates insulin receptor (IR) which leads to activation of phospho-AKT which increases phosphorylated forkhead box 01 (p-FOXO1, gluconeogenesis regulation) and transcriptionally regulates acetyl co-A carboxylase (ACC, de novo lipogenesis (DNL) regulation).

Methods

This is a nested mechanistic study within a randomised controlled clinical trial. We performed molecular analyses (Western blots for protein and qPRC for mRNA expression, respectively, n = 3-4/group) exploring intermediates in the insulin signaling pathway (IR, p-AKT, p-FOXO1, and ACC) in (i) visceral and subcutaneous (SubQ) adipose tissue from women with obesity and PCOS before VSG bariatric surgery (n = 3/group); and (ii) SubQ WAT from women with obesity and PCOS at baseline and six-months after medical intervention with metformin (MTF) and lifestyle modification.

Results

Subcutaneous (SubQ) white adipose tissue (WAT) displayed similar levels of p-ACC compared to visceral WAT from women pre-VSG. Six months of medical care increased p-ACC in SubQ WAT by 5-fold compared to baseline. IR displayed similar expression in the visceral compared to SubQ WAT in women pre-VSG. IR expression increased by 20-fold at 6-months of medical care compared to baseline in SubQ WAT. p-FOXO1 displayed similar expression in the visceral compared to SubQ WAT. However, p-FOXO1 was decreased at 6-months of medical care compared to baseline. p-AKT levels were similar in visceral compared to SubQ WAT pre-VSG. However, p-AKT levels were significantly increased by 4-fold at 6-months of medical care compared to baseline.

Conclusion

None of the insulin signaling intermediates measured were different in visceral compared to SubQ in women with obesity and PCOS. Additionally, the findings indicated lowered DNL, lowered regulation of gluconeogenic genes and thus lowered gluconeogenesis, and increased insulin action in SubQ WAT in women with obesity and PCOS after 6-months of medical care.

Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.