A Bioprinted Model of Pregnant Human Uterine Myometrium

Craig C Ulrich¹Korrina Siddiqui¹Lexa K Baldwin²Weijian Hua³Jacob K Kuklok⁴Jada J Okaikoi⁴Lauren L Parker⁴Juli Petereit⁵Dave R Quilici⁵Grace M Silva⁶Anutr Sivakoses^7,8Jiavanna S Wong-Fortunato⁴Rebekah J Woolsey⁵Adrian West^10,9Yifei Jin¹¹Heather R Burkin^1,12*

• ¹Department of Pharmacology, School of Medicine, University of Nevada, Reno, United States
• ²Department of Pharmacology, School of Medicine University of Nevada,, Reno, United States
• ³Department of Mechanical Engineering, University of Nevada, Reno, Reno, NV, United States
• ⁴Department of Pharmacology, School of Medicine University of Nevada,, Reno, NV, United States
• ⁵Mick D. Hitchcock. Ph.D. Proteomics Center, Reno, NV, United States
• ⁶The University of South Florida Morsani College of Medicine, Tampa, FL, United States
• ⁷The University of Arizona Cancer Center, Tucson, AZ, United States
• ⁸Department of Pathology, Microbiology, and Immunology, The University of Nebraska Medical Center, Omaha, NE, United States
• ⁹Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
• ¹⁰Biology of Breathing Research Theme, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
• ¹¹University of Nevada, Reno Department of Mechanical Engineering, Reno, NV, United States
• ¹²Department of Obstetrics and Gynecology, School of Medicine University of Nevada,, Reno, NV, United States

Despite decades of research, complications associated with dysfunctional labor are leading causes of maternal and neonatal morbidity. Currently available experimental models are not sufficient to understand the complex mechanisms underlying human labor nor to test new therapeutic approaches. We sought to develop a bioprinted tissue model of pregnant human myometrium that replicates the morphological, contractile and molecular characteristics of native pregnant human uterine myometrium as a resource to accelerate basic discovery and pharmacological testing. We have utilized primary human uterine smooth muscle cells to bioprint myometrial tissue rings containing >75% viable cells with elongated, smooth muscle morphology. Immunofluorescence confirmed expression of smooth muscle markers (caldesmon, alpha smooth muscle actin, and smooth muscle myosin), contractile-associated proteins (oxytocin receptor, prostaglandin receptors and connexin-43), and steroid hormone receptors (estrogen and progesterone receptors) characteristic of pregnant human uterine myometrium. Bioprinted tissues contracted in response to physiological agonists oxytocin (p<0.001), prostaglandin F2a p=0.003), and prostaglandin E2 (p<0.001), and relaxed in response to the nitric oxide donor S-nitrosoglutathione (p=0.004). Further development of this model could provide an abundant and homogeneous tissue source to facilitate mechanistic studies and test agents to modulate labor.