Quantitating Oxytocin-induced Contractility in Bioengineered 3D Human Myometrium

PROJECT SUMMARY At term (>37 weeks of gestation), the primary function of the uterine myometrium is to produce forceful contractions to allow delivery of the neonate. Insufficient myometrial contractility during labor may lead to caesarean delivery; lack of contractility following birth can lead to postpartum hemorrhage. Therefore, timely and effective myometrial contractility is central to successful obstetric outcomes. A synthetic form of oxytocin is used to produce forceful myometrial contractions in ~2million women in the United States. However, oxytocin has a wide therapeutic index, with women receiving anywhere between 1-40 mU/min, including prolonged exposure (>24hrs). Both high doses and prolonged oxytocin exposure have adverse maternal and neonatal outcomes. Our ability to titrate oxytocin dosing is sub-optimal partly due to our insufficient understanding of the kinetics of myometrial smooth muscle contractility in response to oxytocin. Current methods of measuring myometrial smooth muscle contractility rely on surrogate collagen contractility assays that do not directly measure the force from contractile smooth muscle structures. The measure of contractility of uterine myometrial biospecimens using organ bath physiology is a gold standard but is limited by an expiry date for ex vivo analyses. Here we propose to bioengineer an in vitro human 3D myometrium, using patient-derived myometrial smooth muscle cells. The resulting bioengineered myometrium will resemble a 3D multi-cell layer thick sheet, with interconnected contractile myometrial smooth muscle cells. Interconnectivity, contractile phenotype, and genotype of bioengineered 3D myometrium will be benchmarked against matched patient-derived biospecimens (Aim 1). Importantly, the proposed studies will directly evaluate the kinetics (amplitude, velocity, and duration) of contraction of bioengineered myometrium in response to varying doses of oxytocin, benchmarked against similar sized matched biospecimens (Aim 2). The proposed studies are expected to result in a new method to directly evaluate myometrial contractility using bioengineered myometrial structures, including establishing quantifiable metrics for oxytocin-induced contractility. By combining bioengineering with physiology, we will establish a new starting point for evaluating drugs and management protocols for labor dysfunction management in patient-derived models of the human uterine myometrium.