Inhibitory Effect of Visfatin and Leptin on Human and Rat Myometrial Contractility

Aims: The purpose of this study was to investigate the effect of visfatin on in vitro myometrial contractility in human and rat, and compare it to leptin.

Main Methods: Myometrial strips from term pregnant women having a caesarean section or rats were dissected, superfused with physiological saline and the effects of visfatin (500pM-25nM) or leptin (1nM-1μM), on spontaneous and oxytocin-induced contractions were studied. After establishment of regular contractions, tissues were incubated for control and test response at 37°C for 20min, and then contractility was assayed.

Key Findings: In human and rat myometrium, visfatin had similar dose dependent effects on contractility. In the human myometrium, compared with that of controls (100%), 10nM produced a significant (paired t-test) decrease in the 20min integral of spontaneous (64±8%, n=13) and oxytocin-induced contractions (55±9%, n=5), mean±SEM. In rat tissue the decrease was also significant (spontaneous, 76±7%, n=7; oxytocin-induced 68±6%, n=3). Leptin at this concentration (10nM) had no effect in rat or human, and even at a higher concentration (1μM) produced only a small inhibitory effect (~ 80%) on contractions.

Significance: These data are the first to show that visfatin inhibits myometrial contractility and does so more potently than leptin. Our data suggest that increased output of visfatin and leptin in obese pregnant women may impair uterine contractility resulting in an unplanned Caesarean delivery.