Increased Cardiovascular Disease Risk in Adult Offspring with Prenatal Opioid Exposure Is Associated with Endogenous Opioid Peptide Dysregulation
Authors: Ahmed Nermin , Malone Jena , Kassis Alana , Dalmasso Carolina , Loria Analia 
Published: May 2024

Parental drug abuse and dysfunctional households during childhood increase the risk for cardiovascular disease (CVD) later in life. Chronic opioid exposure and opioid use disorder (OUD) are associated with a 2-fold increased risk of CVD and a 16% increase in coronary artery disease. OUD among pregnant women is an understudied area related to the opioid epidemic, causing a 5-fold increase in neonatal opioid withdrawal syndrome (NOWS) incidence. In former studies, we subjected female rats to two models of maternal opioid exposure: 1) morphine sulfate during gestation or 2) fentanyl citrate during preconception and gestation. At birth, female and male opioid-exposed offspring showed normal birth weight compared with vehicle-exposed offspring while displaying NOWS-like somatic withdrawal signs after parturition. As adults, in utero opioid-exposed offspring displayed increased mean arterial pressure, sympathetic activation, and CVD risk factors. Prenatal exposure to opioids has been shown to dysregulate the endogenous opioid peptides (EOPs) and alter behavioral outcomes later in life, but the transplacental effects of opioids on blood pressure regulation remain understudied. Therefore, this study aimed to assess whether adult offspring with prenatal opioid exposure display changes in 1) the expression of the EOP proenkephalin (PENK) in brain regions known to control the sympathetic outflow (Paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM)), heart, kidneys, and liver; 2) the plasma levels of EOPs (PENK, enkephalin, prodynorphin and dynorphin); and 3) the fentanyl plasma clearance (pharmacokinetics). Protein was extracted from tissues for western blot analysis using the primary antibody for PENK (1:1000, Invitrogen). In opioid-exposed offspring, PENK protein expression was reduced in RVLM (0.55±0.06 vs. 0.36±0.01, AU) and PVN (1.56±0.09 vs. 1.08±0.08, AU), showing a ~35% and ~31% reduction, respectively (n=4-5, p<0.05). In the heart, PENK protein expression was not statistically different in opioid-exposed offspring compared with vehicle-exposed offspring. However, in the kidneys (0.72±0.09 vs. 1.16±0.10, AU) and liver (0.40±0.06 vs. 0.60±0.05, AU), PENK protein expression showed a 61% and 50% increase only in male opioid-exposed offspring compared to vehicle-exposed offspring (n=6-8, p<0.05). None of the plasma circulating EOP levels measured by ELISA were affected by prenatal opioid exposure. Fentanyl clearance in plasma (0, 15, 30, 60, 120, 360,1440 mins) following a fentanyl injection (20ug/kg, sc.) was not different between adult vehicle and opioid-exposed offspring, indicating potential pharmacodynamic alterations secondary to prenatal opioid exposure. As EOPs exert inhibitory effects on adrenergic signaling, our data indicate that prenatal exposure to opioids may induce a permanent downregulation of EOPs in the central nervous system and thus contributing to increasing the sympathetic tone and desensitize the acute depressor responses to opioid peptides, suggesting that EOPs may be critical for blood pressure regulation. However, peripheral expression of PENK seems to reflect pathophysiological alterations in different tissues since elevated PENK level is used in clinical settings as a marker to assess the severity of tissue damage in the liver and kidneys. This study was funded by 1013177615 (NRPA-UK), 1013400001 (SUGAR-UK) and 1013171360 (DPNS-UK). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.