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Effects of Short Term Metformin Treatment on Brown Adipose Tissue Activity and Plasma Irisin Levels in Women with Polycystic Ovary Syndrome: A Randomized Controlled Trial

Flávia R. Oliveira, M. Mamede, M. Bizzi, A. L. Rocha, C. N. Ferreira, K. B. Gomes, A. L. Cândido, F. Reis

Hormone and Metabolic Research, 2020

24 participants · 17 citations

Abstract

Abstract Polycystic ovary syndrome (PCOS) is a chronic dysfunction associated with obesity and metabolic disorders that can be ameliorated by treatment with metformin. Brown adipose tissue (BAT) has been recently identified in adult humans, and irisin is a myokine that induces BAT formation. The aim of this randomized controlled trial was to evaluate whether a short term treatment with metformin alters BAT activity and plasma irisin levels in women with PCOS. The participants were randomly assigned to receive metformin (1500 mg/day, n=21) or placebo (n=24) during 60 days. BAT activity was assessed by 18F-FDG positron emission tomography-computed tomography (PET-CT) and plasma irisin levels were measured by enzyme immunoassay. The groups were similar in age, body measures, metabolic profile and PCOS phenotypes. BAT activity did not change significantly in the women treated with metformin (median Δ SUVmax=–0.06 g/ml, interquartile interval –2.81 to 0.24 g/ml, p=0.484, Wilcoxon’s test) or placebo (median Δ SUVmax=0.98 g/ml, interquartile interval –2.94 to 4.60 g/ml, p=0.386). In addition, plasma irisin levels remained unchanged in the groups treated with metformin (median Δ=–98 ng/ml, interquartile interval –366 to 60 ng/ml, p=0.310) and placebo (median Δ=28 ng/ml, interquartile interval –1260 to 215 ng/ml, p=0.650). These results suggest that in PCOS women BAT activity and plasma irisin levels may not change after a brief treatment with metformin.

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 24 participants or records.

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