The parent grant (NIH RO1 HL079647 """"""""Genetic Regulation of Hypoxia-Induced Intrauterine Growth Restriction (IUGR)"""""""") tests the overall hypothesis that genetic variants in hypoxia-inducible transcription (HIF)-targeted or regulatory pathways protect multigenerational high-altitude residents from hypoxia-associated IUGR. Serial studies are proposed during pregnancy and postpartum in 100 high- (3600 m) and 100 low- (300 m) altitude residents, divided between women of multigenerational high-altitude (Andean) or low-altitude (European) ancestry.
Specific aims test whether 1) Andean ancestry is protective against hypoxia-induced IUGR due to genetic factors influencing HIF-targeted gene products and uterine artery (UA) blood flow, 2) HIF-targeted and -regulatory genes contribute to UA blood flow and fetal growth variability and 3) HIF-regulated genes influencing UA vasoconstriction, vasodilation, or growth contribute to the variation in maternal physiologic responses to pregnancy in Andeans vs. Europeans. In this FIRCA, we propose to extend our studies to test the hypothesis that gestation and birth in a hypoxic environment result in lifelong alterations in control of breathing and lung structure, with consequent functional alterations that increase susceptibility to Chronic Mountain Sickness (CMS) in adulthood.
Our specific aims, which extend the fetal origins hypothesis to abnormalities of the pulmonary circulation and/or control of breathing, are to 1) characterize the phenotype of young adults with elevated hemoglobin levels or excessive erythrocytosis (EE), an early form of CMS, with respect to a) control of breathing during wakefulness and sleep, b) lung structure and function, c) pulmonary circulation and d) redox status and to 2) establish whether individuals with EE were more hypoxic during perinatal life by comparing them with a group of healthy controls with respect to the prevalence with which they experienced a) fetal growth reduction, b) preeclampsia, c) neonatal hypoxia. Our and others'recent work support the proposed hypothesis that EE has perinatal origins. The proposed study will identify 150 male (aged 15-25) residents of high altitudes (e3600m);75 with EE and 75 healthy controls. The subjects, matched by age and altitude of residence, will be compared with respect to control of breathing during sleep and wakefulness, lung structure and function, pulmonary circulation, redox status and hematological characteristics. Interviews and medical-record reviews will be conducted to evaluate the relationship between chronic hypoxia during the perinatal period or reduced fetal growth and EE in adulthood. The relationship between these maternal and perinatal characteristics, ventilatory function, lung structure and pulmonary circulation abnormalities, redox status and EE in adulthood will be determined using a series of logistic and linear regression analyses, as appropriate. Understanding the origins of CMS will aid in the early recognition and possible prevention of this public health problem which affects ~ 10% of adult men, or 10 million persons worldwide and constitutes a major cause of morbidity and mortality in the highland regions of South America, Asia and the United States. PERFORMANCE SITE(S) (organization, city, state) USA site: Foreign site: Lorna G. Moore, PhD Enrique Vargas, MD Altitude Research Center Instituto Boliviano de Biologma de Altura University of Colorado Denver Edificio IBBA - Calle Claudio Sanjmnes s/n Frente al Torax, Miraflores;La Paz, Bolivia KEY PERSONNEL: Lorna G. Moore, PhD University of Colorado Denver PI Enrique Vargas, MD Instituto Boliviano de Biologma de Altura Foreign Collaborator Colleen Glyde Julian, PhD University of Colorado Denver Co-investigator David Lynch, MD National Jewish Medical and Research Center Co-investigator Daniela Davila, MD Instituto Boliviano de Biologma de Altura Co-investigator Susan Niermeyer, MD University of Colorado Denver Consultant Teofilo Lee-Chiong, MD National Jewish Medical and Research Center Consultant John Kittelson, PhD University of Colorado Denver Consultant Joe McCord, PhD University of Colorado Denver Consultant
CMS is a common but poorly understood disorder affecting up to 10 million persons worldwide. It has no known remedy, except descent to lower altitudes, and can result in death from pulmonary hypertension and right heart failure. Our proposed studies pose the novel question as to whether CMS has perinatal origins. If so, interventions and/or more effective treatments can be designed to cure and ultimately prevent this disorder.
