Thomas Ebert, Susan Kralisch, Ulrike Wurst, Ulrike Lössner, Jürgen Kratzsch, Matthias Blüher, Michael Stumvoll, Anke Tönjes and Mathias Fasshauer
Betatrophin has recently been introduced as a novel adipokine/hepatokine, which promotes pancreatic β cell proliferation and improves glucose tolerance in several mouse models of insulin resistance. However, regulation of betatrophin in gestational diabetes mellitus (GDM), as well as its association with markers of obesity, such as glucose and lipid metabolism, inflammation, and renal function, have not been elucidated.
Design and methods
Circulating betatrophin was quantified in 74 women with GDM and 74 healthy and gestational age-matched controls by ELISA. In a subset of the study population comprising of 85 patients (41 previous controls, 44 previous women with GDM), postpartum betatrophin levels were measured in a follow-up study.
Median (interquartile range) serum betatrophin levels were higher in women with GDM (1.79 (0.53) μg/l) as compared to non-diabetic pregnant controls (1.58 (0.44) μg/l) (P=0.002). In multivariate analysis, GDM status was an independent and positive predictor of circulating betatrophin (P=0.001). Furthermore, betatrophin levels were significantly higher during gestation (1.70 (0.53) μg/l) as compared to postpartum levels (1.55 (0.66) μg/l) (P=0.028). Moreover, postpartum irisin remained a positive and independent predictor of postpartum betatrophin concentrations.
Women with GDM have significantly higher betatrophin levels as compared to healthy pregnant controls and GDM status positively predicts circulating betatrophin. Furthermore, postpartum levels are significantly lower as compared to betatrophin concentrations during pregnancy. Moreover, irisin is a significant predictor of postpartum betatrophin levels.
Thomas Ebert, Denise Focke, David Petroff, Ulrike Wurst, Judit Richter, Anette Bachmann, Ulrike Lössner, Susan Kralisch, Jürgen Kratzsch, Joachim Beige, Ingolf Bast, Matthias Anders, Matthias Blüher, Michael Stumvoll and Mathias Fasshauer
Irisin has recently been introduced as a novel myokine which reverses visceral obesity and improves glucose metabolism in mice. However, regulation of irisin in humans in relation to renal and metabolic disease has not been comprehensively studied.
Design and methods
Serum irisin levels were quantified by ELISA and correlated with anthropometric and biochemical parameters of renal function, glucose and lipid metabolism, as well as inflammation, in 532 patients with stages 1–5 of chronic kidney disease (CKD).
Median serum irisin levels adjusted for age, gender, and BMI significantly decreased with increasing CKD stage and lowest concentrations were seen in patients with CKD stage 5. Furthermore, irisin concentrations were associated with facets of the metabolic syndrome including diastolic blood pressure, markers of impaired glucose tolerance, and dyslipidemia in univariate analysis. Moreover, markers of renal function, e.g. glomerular filtration rate, and insulin resistance, e.g. homeostasis model assessment of insulin resistance, remained independently associated with circulating irisin levels in robust multivariate analysis.
We show that irisin serum concentrations decrease with increasing CKD stage and are independently and positively predicted by renal function and insulin resistance. The physiological relevance of our findings, as well as the factors contributing to irisin regulation in humans, needs to be further defined in future experiments.