Abstract
Opioid use disorder affects males and females differently, yet the molecular mechanisms are understudied in neonates. Our laboratory has demonstrated differential sex effects of opioids on the reward and inflammatory pathways related to neonatal feeding behavior that may affect growth and cardiometabolic outcomes. This observational pilot study examined the sex-specific impact of maternal opioid use during pregnancy on reward, energy homeostasis, inflammation, oxidative stress, and neuropathology pathways in offspring. Saliva from nine opioid-exposed and nine non-exposed neonates collected within 48 hours after birth underwent a multiplex, high-throughput analysis of 72 select genes using NanoString's nCounter(®) system (NanoString Technologies, Seattle, WA, USA. Despite low RNA abundance in neonatal saliva, experimental conditions were optimized after several trials. Multiplex analysis demonstrated sex-specific molecular effects of maternal opioid use, i.e., upregulated pathways related to reward, inflammation, oxidative stress, feeding, and energy homeostasis pathways in males, and downregulated pathways related to inflammation and cardiovascular function in females. This pilot study demonstrates the feasibility of multiplexing neonatal saliva using a high-throughput platform. Future work will replicate these methods and validate findings in a larger sample to clarify the sex-specific short and long-term impact of maternal opioid use on health outcomes.