Pulsatile interleukin-6 leads CRH secretion and is associated with myometrial contractility during the active phase of term human labor.
OBJECTIVE
Our objective was to investigate IL-6 and CRH secretion during the active phase of human labor and to define their potential involvement in myometrial contractility.


METHODS
Twenty-two primigravid women were studied for 90 minutes during the active phase of term labor by serial plasma sampling every 3 minutes for measurement of IL-6 and CRH concentrations. Uterine contractions, measured by cardiotocograph, were evaluated in Montevideo units. Basic, quantitative, pulsatility, and time cross-correlation statistical analyses were performed.


RESULTS
By linear regression analysis, a positive correlation was observed between IL-6 and CRH total mean area under the curve above 0 (r = 0.76184, P = .006). Mean number of pulses was 2.00 ± 0.70 and 3.33 ± 1.29 for IL-6 and CRH, respectively. There was a significant positive correlation between IL-6 and CRH over time, peaking at the 12-minute interval, with IL-6 leading CRH. Also, there was a significant positive correlation between myometrial contractility expressed in Montevideo units and IL-6 concentrations over time, starting at +51 minutes and ending at +57 minutes with myometrial contractility leading IL-6. No significant correlation was found between myometrial contractility and CRH concentrations over time.


CONCLUSIONS
IL-6 and CRH are both secreted in a pulsatile fashion during the active phase of human labor. The time-integrated concentrations of the two hormones are positively correlated, with IL-6 leading CRH secretion. It appears, thus, that proinflammatory mediators may be direct and/or indirect promoters of placental CRH release. Furthermore, the secretion of IL-6, which is a myokine, seems to be associated positively with uterine contractility. Additional studies are needed to elucidate the combined effect of inflammation, placental CRH release, and/or the receptors of the latter in parturition.
MD, PhD, 3 Neofytou Vamva Street, 10674 Athens, Greece. mastorakg@ath.forthnet.gr.
Dimitrios C
DC
Papatheodorou
Lazaros K
LK
Karagiannidis
George
G
Paltoglou
Alexandra
A
Margeli
George
G
Kaparos
George
G
Valsamakis
George P
GP
Chrousos
George
G
Creatsas
George
G
Mastorakos
D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D007743:Labor, Obstetric / Q000502:physiology*; D011247:Pregnancy; D014590:Uterine Contraction / Q000502:physiology*
D015850:Interleukin-6; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone