Ryan, Benjamin J.;
Van Pelt, Douglas W.;
Guth, Lisa M.;
Ludzki, Alison C.;
Gioscia‐Ryan, Rachel A.;
Ahn, Chiwoon;
Foug, Katherine L.;
Horowitz, Jeffrey F.
Plasma ferritin concentration is positively associated with in vivo fatty acid mobilization and insulin resistance in obese women
Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Plasma ferritin concentration is positively associated with in vivo fatty acid mobilization and insulin resistance in obese women
Beteiligte:
Ryan, Benjamin J.;
Van Pelt, Douglas W.;
Guth, Lisa M.;
Ludzki, Alison C.;
Gioscia‐Ryan, Rachel A.;
Ahn, Chiwoon;
Foug, Katherine L.;
Horowitz, Jeffrey F.
Beschreibung:
<jats:sec><jats:title>New Findings</jats:title><jats:p><jats:list list-type="bullet">
<jats:list-item><jats:p><jats:bold>What is the central question of this study?</jats:bold></jats:p>
<jats:p>Do obese women with relatively high whole‐body iron stores exhibit elevated <jats:italic>in vivo</jats:italic> rates of fatty acid (FA) release from adipose tissue compared with a well‐matched cohort of obese women with relatively low iron stores?</jats:p>
</jats:list-item>
<jats:list-item><jats:p><jats:bold>What is the main finding and its importance?</jats:bold></jats:p>
<jats:p>Obese women with high plasma [ferritin] (a marker of whole‐body iron stores) had greater FA mobilization, lipolytic activation in adipose tissue and insulin resistance (IR) compared with obese women with lower plasma [ferritin]. Given that elevated FA mobilization is intimately linked with the development of IR, these findings suggest that elevated iron stores might contribute to IR in obesity by increasing systemic FA availability.</jats:p>
</jats:list-item>
</jats:list></jats:p></jats:sec><jats:sec><jats:title>Abstract</jats:title><jats:p>High rates of fatty acid (FA) mobilization from adipose tissue are associated with insulin resistance (IR) in obesity. <jats:italic>In vitro</jats:italic> evidence suggests that iron stimulates lipolysis in adipocytes, but whether iron is related to <jats:italic>in vivo</jats:italic> FA mobilization is unknown. We hypothesized that plasma ferritin concentration ([ferritin]), a marker of body iron stores, would be positively associated with FA mobilization. We measured [ferritin], the rate of appearance of FA in the systemic circulation (FA Ra; stable isotope dilution), key adipose tissue lipolytic proteins and IR (hyperinsulinaemic–euglycaemic clamp) in 20 obese, premenopausal women. [Ferritin] was correlated with FA Ra (<jats:italic>r</jats:italic> = 0.65; <jats:italic>P</jats:italic> = 0.002) and IR (<jats:italic>r</jats:italic> = 0.57; <jats:italic>P</jats:italic> = 0.008); these relationships remained significant after controlling for body mass index and plasma [C‐reactive protein] (a marker of systemic inflammation) in multiple regression analyses. We then stratified subjects into tertiles based on [ferritin] to compare subjects with ‘High‐ferritin’ <jats:italic>versus</jats:italic> ‘Low‐ferritin’. Plasma [hepcidin] was more than fivefold greater (<jats:italic>P</jats:italic> < 0.05) in the High‐ferritin <jats:italic>versus</jats:italic> Low‐ferritin group, but there was no difference in plasma [C‐reactive protein] between groups, indicating that the large difference in plasma [ferritin] reflects a difference in iron stores, not systemic inflammation. We found that FA Ra, adipose protein abundance of hormone‐sensitive lipase and adipose triglyceride lipase, and IR were significantly greater in subjects with High‐ferritin <jats:italic>versus</jats:italic> Low‐ferritin (all <jats:italic>P</jats:italic> < 0.05). These data provide the first evidence linking iron and <jats:italic>in vivo</jats:italic> FA mobilization and suggest that elevated iron stores might contribute to IR in obesity by increasing systemic FA availability.</jats:p></jats:sec>