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Helena Parfenova, PhD

Department of Physiology

The University of Tennessee Health Science Center
894 Union Avenue
Memphis, TN 38163
Phone: 901.448.8319
Fax: 901.448.7126
Lab: 305 Nash Research Building
Email: Helena (Elena) Parfenova


  • PhD Institution: Institute of Cytology, St Petersburg, Russia


Research Interests

We investigate the roles of heme oxygenase (HO) and carbon monoxide (CO), the HO-derived endogenous gaseous mediator, in regulating blood flow to the brain and in promoting survival of brain endothelial cells during cerebral vascular insult caused by seizures and oxidative stress. Seizures cause sustained cerebral vascular injury, reduction of endothelial vasodilator function, and loss of cerebral blood flow regulation. Glutamate, an excitatory neurotransmitter, and TNFa, a pro-inflammatory cytokine, are major injurious factors involved in the pathogenesis of seizure-induced cerebral vascular injury and endothelial apoptosis. Activation of endogenous HO/CO system or pharmacological delivery of CO to the brain reduces or prevents cerebral vascular endothelial injury and restores cerebral vascular endothelial function.

We investigate the HO/CO system as a critical component of anti-apoptotic mechanisms involved in protecting the brain from cerebral vascular injury caused by seizures and oxidative stress. The projects involve in vivo and in vitro studies in newborn pigs using the closed cranial window techniques for detection of cerebral blood flow responses, isolated cerebral resistance arterioles, and primary cultures of cerebral vascular endothelial, smooth muscle, and glial cells. My ultimate goal is to translate the knowledge gained from the animal models to pediatric practice to correct the deteriorating neurological outcome of neonatal cerebrovascular insults

Research Support

  • Home Oxygenase and Cerebral Vascular Injury. NIHLBI/NIH. 6/1/4-5/31/14 P.I.
  • Cerebrovascular Stress and Circulating Endothelial Cells. NINDS/NIHLBI. 2/1/10-1/31/15 P.I.
  • Control of neonatal circulation. NHLBI/NIH. 4/1/1984-3/31/2017 (Co-I, CW Leffler, P.I.)
  • Hydrogen Sulfide in Newborn Cerebral Circulation. NIHLBI/NIH. 8/1/1990-7/31/2015 (Co-I, CW Leffler, P.I.)

Representative Publications

  • Parfenova H, Liu J, Hoover DT, Fedinec AL. Vasodilator effects of sulforaphane in cerebral circulation: A critical role of endogenously produced hydrogen sulfide and arteriolar smooth muscle K(ATP) and BK channels in the brain. J Cereb Blood Flow Metab. 2019 Oct 9:271678X19878284. doi: 10.1177/0271678X19878284. [Epub ahead of print] PubMed PMID: 31594422.
  • Patel S, Fedinec AL, Liu J, Weiss MA, Pourcyrous M, Harsono M, Parfenova H, Leffler CW. H(2)S mediates the vasodilator effect of endothelin-1 in the cerebral circulation. Am J Physiol Heart Circ Physiol. 2018 Dec 1;315(6):H1759-H1764. doi: 10.1152/ajpheart.00451.2018. Epub 2018 Sep 28. PubMed PMID: 30265150; PubMed Central PMCID: PMC6336977.
  • Parfenova H, Pourcyrous M, Fedinec AL, Liu J, Basuroy S, Leffler CW. Astrocyte-produced carbon monoxide and the carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by prolonged neonatal asphyxia. Am J Physiol Heart Circ Physiol. 2018 Oct 1;315(4):H978-H988. doi: 10.1152/ajpheart.00140.2018. Epub 2018 Jul 20. PubMed PMID: 30028198; PubMed Central PMCID: PMC6230909.
  • Pourcyrous M, Chilakala S, Elabiad MT, Parfenova H, Leffler CW. Does prolonged severe hypercapnia interfere with normal cerebrovascular function in piglets? Pediatr Res. 2018 Aug;84(2):290-295. doi: 10.1038/s41390-018-0061-5. Epub 2018 May 28. PubMed PMID: 29907849; PubMed Central PMCID: PMC6185793.
  • Liu J, Pourcyrous M, Fedinec AL, Leffler CW, Parfenova H. Preventing harmful effects of epileptic seizures on cerebrovascular functions in newborn pigs: does sex matter? Pediatr Res. 2017 Nov;82(5):881-887. doi: 10.1038/pr.2017.152. Epub 2017 Aug 16. PubMed PMID: 28665933; PubMed Central PMCID: PMC5645245.
  • Myers MH, Jolly E, Li Y, de Jongh Curry A, Parfenova H. Power Spectral Density Analysis of Electrocorticogram Recordings during Cerebral Hypothermia in Neonatal Seizures. Ann Neurosci. 2017 May;24(1):12-19. doi: 10.1159/000464418. Epub 2017 Apr 21. PubMed PMID: 28596673; PubMed Central PMCID: PMC5460947.

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May 26, 2022