Impact of hyperleptinemia during placental ischemia-induced hypertension in pregnant rats
Abstract
The prevalence of preeclampsia and obesity have increased. Although obesity is a major risk factor for preeclampsia, the mechanisms linking these morbidities are poorly understood. Circulating leptin levels increase in proportion to fat mass. Infusion of this adipokine elicits hypertension in nonpregnant rats, but less is known about how hyperleptinemia impacts blood pressure during placental ischemia, an initiating event in the pathophysiology of hypertension in preeclampsia. We tested the hypothesis that hyperleptinemia during reduced uterine perfusion pressure (RUPP) exaggerates placental ischemia-induced hypertension. On gestational day (GD) 14, Sprague–Dawley rats were implanted with osmotic mini-pumps delivering recombinant rat leptin (1 µg/kg/min iv) or vehicle concurrently with the RUPP procedure to induce placental ischemia or Sham. On GD 19, plasma leptin was elevated in Sham + Leptin and RUPP + Leptin. Leptin infusion did not significantly impact mean arterial pressure (MAP) in Sham. MAP was increased in RUPP + Vehicle vs. Sham + Vehicle. In contrast to our hypothesis, placental ischemia-induced hypertension was attenuated by leptin infusion. To examine potential mechanisms for attenuation of RUPP-induced hypertension during hyperleptinemia, endothelial-dependent vasorelaxation to acetylcholine was similar between Sham and RUPP; however, endothelial-independent vasorelaxation to the nitric oxide (NO)-donor, sodium nitroprusside, was increased in Sham and RUPP. These findings suggest that NO/cyclic guanosine monophosphate (cGMP) signaling was increased in the presence of hyperleptinemia. Plasma cGMP was elevated in Sham and RUPP hyperleptinemic groups compared with vehicle groups but plasma and vascular NO metabolites were reduced. These data suggest that hyperleptinemia during placental ischemia attenuates hypertension by compensatory increases in NO/cGMP signaling.
NEW & NOTEWORTHY Ours is the first study to examine the impact of hyperleptinemia on the development of placental ischemia-induced hypertension using an experimental animal model.
REFERENCES
- 1. . Hypertensive disease of pregnancy and maternal mortality. Curr Opin Obstet Gynecol 25: 124–132, 2013. doi:10.1097/GCO.0b013e32835e0ef5.
Crossref | PubMed | ISI | Google Scholar - 2. . The burden of hypertensive disorders of pregnancy in Africa: a systematic review and meta-analysis. J Clin Hypertens 21: 479–488, 2019. doi:10.1111/jch.13514.
Crossref | PubMed | ISI | Google Scholar - 3. . Hypertensive disorders in pregnancy and stillbirth rates: a facility-based study in China. Bull World Health Organ 96: 531–539, 2018. doi:10.2471/BLT.18.208447.
Crossref | PubMed | ISI | Google Scholar - 4. . Hypertensive disorders of pregnancy and future maternal cardiovascular risk. J Am Heart Assoc 7:
e009382 , 2018. doi:10.1161/JAHA.118.009382.
Crossref | PubMed | ISI | Google Scholar - 5.
American College of Obstetricians and Gynecologists' Task Force on Hypertension in Pregnancy . Hypertension in pregnancy. Report of the American College of Obstetricians and Gynecologists' Task Force on Hypertension in Pregnancy. Obstet Gynecol 122: 1122–1131, 2013. doi:10.1097/01.AOG.0000437382.03963.88.
Crossref | PubMed | ISI | Google Scholar - 6. . Super-obesity and risk for early and late pre-eclampsia. BJOG 117: 997–1004, 2010. doi:10.1111/j.1471-0528.2010.02593.x.
Crossref | PubMed | ISI | Google Scholar - 7. . Estimated global overweight and obesity burden in pregnant women based on panel data model. PLoS One 13:
e0202183 , 2018. doi:10.1371/journal.pone.0202183.
Crossref | PubMed | ISI | Google Scholar - 8. . Leptin in ruminants. Gene expression in adipose tissue and mammary gland, and regulation of plasma concentration. Domest Anim Endocrinol 21: 271–295, 2001. doi:10.1016/s0739-7240(01)00124-2.
Crossref | PubMed | ISI | Google Scholar - 9. . Role of leptin and central nervous system melanocortins in obesity hypertension. Curr Opin Nephrol Hypertens 22: 135–140, 2013. doi:10.1097/MNH.0b013e32835d0c05.
Crossref | PubMed | ISI | Google Scholar - 10. . Chronic CNS-mediated cardiometabolic actions of leptin: potential role of sex differences. Am J Physiol Regul Integr Comp Physiol 320: R173–R181, 2021. doi:10.1152/ajpregu.00027.2020.
Link | ISI | Google Scholar - 11. . Serum leptin levels in relation to circulating cytokines, chemokines, adhesion molecules and angiogenic factors in normal pregnancy and preeclampsia. Reprod Biol Endocrinol 9:
124 , 2011. doi:10.1186/1477-7827-9-124.
Crossref | PubMed | ISI | Google Scholar - 12. . Angiogenic factor screening in women with mild preeclampsia - new and significant proteins in plasma. Cytokine 106: 125–130, 2018. doi:10.1016/j.cyto.2017.10.020.
Crossref | PubMed | ISI | Google Scholar - 13. . Correlations between circulating levels of adipokines and anti-angiogenic factors in women with BMI <30 and a late-onset preeclampsia. Hypertens Pregnancy 33: 72–80, 2014. doi:10.3109/10641955.2013.837174.
Crossref | PubMed | ISI | Google Scholar - 14. . Maternal plasma leptin is increased in preeclampsia and positively correlates with fetal cord concentration. Am J Obstet Gynecol 180: 731–736, 1999. doi:10.1016/S0002-9378(99)70280-2.
Crossref | PubMed | ISI | Google Scholar - 15. . Resistance to the sympathoexcitatory effects of insulin and leptin in late pregnant rats. J Physiol 597: 4087–4100, 2019. doi:10.1113/JP278282.
Crossref | PubMed | ISI | Google Scholar - 16. . Chronic hyperleptinemia results in the development of hypertension in pregnant rats. Am J Physiol Regul Integr Comp Physiol 308: R855–R861, 2015. doi:10.1152/ajpregu.00286.2014.
Link | ISI | Google Scholar - 17. . In vitro ischemia-reperfusion injury in term human placenta as a model for oxidative stress in pathological pregnancies. Am J Pathol 159: 1031–1043, 2001. doi:10.1016/S0002-9440(10)61778-6.
Crossref | PubMed | ISI | Google Scholar - 18. . Preeclampsia, biomarkers, syncytiotrophoblast stress, and placental capacity. Am J Obstet Gynecol 213:
S9.e1 , 2015. doi:10.1016/j.ajog.2015.08.003.
Crossref | ISI | Google Scholar - 19. . Reduced uterine perfusion pressure during pregnancy in the rat is associated with increases in arterial pressure and changes in renal nitric oxide. Hypertension 37: 1191–1195, 2001. doi:10.1161/01.HYP.37.4.1191.
Crossref | PubMed | ISI | Google Scholar - 20. . Placental weight relative to birth weight and long-term cardiovascular mortality: findings from a cohort of 31,307 men and women. Am J Epidemiol 170: 622–631, 2009. doi:10.1093/aje/kwp182.
Crossref | PubMed | ISI | Google Scholar - 21. . Nitric oxide synthase-mediated blood pressure regulation in obese melanocortin-4 receptor-deficient pregnant rats. Am J Physiol Regul Integr Comp Physiol 311: R851–R857, 2016. doi:10.1152/ajpregu.00285.2016.
Link | ISI | Google Scholar - 22. . Mesenteric arterial function in the rat in pregnancy: role of sympathetic and sensory-motor perivascular nerves, endothelium, smooth muscle, nitric oxide and prostaglandins. Br J Pharmacol 117: 1463–1470, 1996. doi:10.1111/j.1476-5381.1996.tb15307.x.
Crossref | PubMed | ISI | Google Scholar - 23. . Atrial and brain natriuretic peptides inhibit the endothelin-1 secretory response to angiotensin II in porcine aorta. Circ Res 70: 241–247, 1992. doi:10.1161/01.res.70.2.241.
Crossref | PubMed | ISI | Google Scholar - 24. . Obesity and gynaecological and obstetric conditions: umbrella review of the literature. BMJ 359:
j4511 , 2017. doi:10.1136/bmj.j4511.
Crossref | PubMed | Google Scholar - 25. . Longitudinal analysis of maternal plasma leptin concentrations during normal pregnancy and pre-eclampsia. Hum Reprod 15: 2033–2036, 2000. doi:10.1093/humrep/15.9.2033.
Crossref | PubMed | ISI | Google Scholar - 26. . Maternal serum leptin as a marker of preeclampsia. Arch Gynecol Obstet 288: 1317–1322, 2013. doi:10.1007/s00404-013-2915-8.
Crossref | PubMed | ISI | Google Scholar - 27. . Umbilical cord plasma leptin is increased in preeclampsia. Am J Obstet Gynecol 186: 427–432, 2002. doi:10.1067/mob.2002.120486.
Crossref | PubMed | ISI | Google Scholar - 28. . Serum leptin measured in early pregnancy is higher in women with preeclampsia compared with normotensive pregnant women. Hypertension 65: 594–599, 2015. doi:10.1161/HYPERTENSIONAHA.114.03979.
Crossref | PubMed | ISI | Google Scholar - 29. . Free leptin is increased in normal pregnancy and further increased in preeclampsia. Metabolism 49: 1043–1048, 2000. doi:10.1053/meta.2000.7707.
Crossref | PubMed | ISI | Google Scholar - 30. . Pathophysiology of ischemic placental disease. Semin Perinatol 38: 139–145, 2014. doi:10.1053/j.semperi.2014.03.005.
Crossref | PubMed | ISI | Google Scholar - 31. . Chronic cardiovascular and renal actions of leptin: role of adrenergic activity. Hypertension 39: 496–501, 2002. doi:10.1161/hy0202.104398.
Crossref | PubMed | ISI | Google Scholar - 32. . The levels of leptin, adiponectin, and resistin in normal weight, overweight, and obese pregnant women with and without preeclampsia. Am J Obstet Gynecol 193: 979–983, 2005. doi:10.1016/j.ajog.2005.06.041.
Crossref | PubMed | ISI | Google Scholar - 33. . Maternal adipokines and insulin as biomarkers of pregnancies complicated by overweight and obesity. Diabetol Metab Syndr 8:
68 , 2016. doi:10.1186/s13098-016-0184-y.
Crossref | PubMed | ISI | Google Scholar - 34. Hypertensive response to chronic NO synthase inhibition is different in Sprague-Dawley rats from two suppliers. Am J Physiol Regul Integr Comp Physiol 275: R1719–R1723, 1998. doi:10.1152/ajpregu.1998.275.5.R1719.
Link | ISI | Google Scholar - 35. . Enhanced vascular reactivity during inhibition of nitric oxide synthesis in pregnant rats. Hypertension 31: 1065–1069, 1998. doi:10.1161/01.hyp.31.5.1065.
Crossref | PubMed | ISI | Google Scholar - 36. . Inhibition of NO synthesis enhances chronic cardiovascular and renal actions of leptin. Hypertension 37: 670–676, 2001 [Erratum in Hypertension 44: e2, 2004]. doi:10.1161/01.hyp.37.2.670.
Crossref | PubMed | ISI | Google Scholar - 37. . Novel nitric oxide synthase–dependent mechanism of vasorelaxation in small arteries from hypertensive rats. Hypertension 49: 893–901, 2007. doi:10.1161/01.HYP.0000259669.40991.1e.
Crossref | PubMed | ISI | Google Scholar - 38. . Mesenteric vascular responsiveness in a rat model of pregnancy-induced hypertension. Exp Biol Med (Maywood) 231: 1398–1402, 2006. doi:10.1177/153537020623100813.
Crossref | PubMed | ISI | Google Scholar - 39. . Postpartum vascular dysfunction in the reduced uteroplacental perfusion model of preeclampsia. PLoS One 11:
e0162487 , 2016. doi:10.1371/journal.pone.0162487.
Crossref | PubMed | ISI | Google Scholar - 40. . Characterisation of the selective reduced uteroplacental perfusion (sRUPP) model of preeclampsia. Sci Rep 9:
9565 , 2019. doi:10.1038/s41598-019-45959-6.
Crossref | PubMed | ISI | Google Scholar - 41. . Nitric oxide and cGMP cause vasorelaxation by activation of a charybdotoxin-sensitive K channel by cGMP-dependent protein kinase. Proc Natl Acad Sci USA 91: 7583–7587, 1994. doi:10.1073/pnas.91.16.7583.
Crossref | PubMed | ISI | Google Scholar - 42. . Alterations in cyclic GMP levels in preeclampsia may reflect increased B-type natriuretic peptide levels and not impaired nitric oxide activity. Clin Biochem 44: 1012–1014, 2011. doi:10.1016/j.clinbiochem.2011.05.026.
Crossref | PubMed | ISI | Google Scholar - 43. . Brain-mediated antidiabetic, anorexic, and cardiovascular actions of leptin require melanocortin-4 receptor signaling. J Neurophysiol 113: 2786–2791, 2015. doi:10.1152/jn.00911.2014.
Link | ISI | Google Scholar - 44. . Maternal obesity and the developmental programming of hypertension: a role for leptin. Acta Physiol (Oxf) 210: 508–523, 2014. doi:10.1111/apha.12223.
Crossref | PubMed | ISI | Google Scholar - 45. . A new mouse model to explore therapies for preeclampsia. PLoS One 5:
e13663 , 2010. doi:10.1371/journal.pone.0013663.
Crossref | PubMed | ISI | Google Scholar - 46. . Leptin in pregnancy and development: a contributor to adulthood disease? Am J Physiol Endocrinol Metab 308: E335–E350, 2015. doi:10.1152/ajpendo.00312.2014.
Link | ISI | Google Scholar - 47. . Leptin action in normal and pathological pregnancies. J Cell Mol Med 22: 716–727, 2018. doi:10.1111/jcmm.13369.
Crossref | PubMed | ISI | Google Scholar - 48. . Adiposity and hyperleptinemia during the first trimester among pregnant women with preeclampsia. Int J Womens Health 9: 449–454, 2017. doi:10.2147/IJWH.S134088.
Crossref | PubMed | ISI | Google Scholar - 49. . Leptin and adiponectin as markers for preeclampsia in obese pregnant women, a cohort study. Pregnancy Hypertens 15: 78–83, 2019. doi:10.1016/j.preghy.2018.12.002.
Crossref | PubMed | ISI | Google Scholar

