title: Erythropoietin regulates hypoxic ventilation in mice by interacting with brainstem and carotid bodies.
abstract: Apart from its role in elevating red blood cell number, erythropoietin (Epo) exerts protective functions in brain, retina and heart upon ischaemic injury. However, the physiological non-erythroid functions of Epo remain unclear. Here we use a transgenic mouse line (Tg21) constitutively overexpressing human Epo in brain to investigate Epo's impact on ventilation upon hypoxic exposure. Tg21 mice showed improved ventilatory response to severe acute hypoxia and moreover improved ventilatory acclimatization to chronic hypoxic exposure. Furthermore, following bilateral transection of carotid sinus nerves that uncouples the brain from the carotid body, Tg21 mice adapted their ventilation to acute severe hypoxia while chemodenervated wild-type (WT) animals developed a life-threatening apnoea. These results imply that Epo in brain modulates ventilation. Additional analysis revealed that the Epo receptor (EpoR) is expressed in the main brainstem respiratory centres and suggested that Epo stimulates breathing control by alteration of catecholaminergic metabolism in brainstem. The modulation of hypoxic pattern of ventilation after i.v. injection of recombinant human Epo in WT mice and the dense EpoR immunosignal observed in carotid bodies showed that these chemoreceptors are sensitive to plasma levels of Epo. In summary, our results suggest that Epo controls ventilation at the central (brainstem) and peripheral (carotid body) levels. These novel findings are relevant to understanding better respiratory disorders including those occurring at high altitude.
authors.affiliation: Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Switzerland.
authors.forename: Jorge
authors.initials: J
authors.lastname: Soliz
authors.forename: Vincent
authors.initials: V
authors.lastname: Joseph
authors.forename: Christophe
authors.initials: C
authors.lastname: Soulage
authors.forename: Csilla
authors.initials: C
authors.lastname: Becskei
authors.forename: Johannes
authors.initials: J
authors.lastname: Vogel
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Pequignot
authors.forename: Omolara
authors.initials: O
authors.lastname: Ogunshola
authors.forename: Max
authors.initials: M
authors.lastname: Gassmann
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001273:Atmosphere Exposure Chambers; D002339:Carotid Arteries / Q000294:innervation; D002344:Carotid Body / Q000187:drug effects / Q000378:metabolism*; D003714:Denervation; D004921:Erythropoietin / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009638:Norepinephrine / Q000378:metabolism; D010101:Oxygen Consumption; D017467:Receptors, Erythropoietin / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D011994:Recombinant Proteins; D012119:Respiration; D012125:Respiratory Center / Q000187:drug effects / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D017467:Receptors, Erythropoietin; D018040:Receptors, Neurokinin-1; D011994:Recombinant Proteins; D004921:Erythropoietin; D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine