I finally understood the guts coming out symbology... they are umbilical cords, Makima as the Devil of Control those are the manifestation of her power, her connection to her "children" and the symbol of her "love".
I love to hate and hate to love this woman, Makima is easily one of the best villains of all manga story.
As far as i can see the author can very well end this manga with the villain winning, and i wouldn't mind, but i hope be what the end will be the author makes it as badass as the rest of the manga is.