title: Environmental Factors Responsible for Variability of Hepatic Vein Flow: A Doppler Assessment in Healthy Twins.
abstract: Doppler interrogation studies of the liver blood flow indicate altered hepatic vein waveforms in association with impaired hepatocellular function. However, little is known about the mechanisms responsible for variations of these parameters in the absence of disease. We aimed to investigate the contribution of heritable and environmental factors to the physiological variability of hepatic vein flow in a twin cohort. Two hundred twenty-eight healthy adult Hungarian twins (69 monozygotic, 45 same-sex dizygotic pairs) underwent Doppler sonography of the hepatic vein. Age- and sex-adjusted heritability of the highest velocity (amplitude of S wave) of hepatic vein flow was negligible. Shared environment contributed to 33% (95% CI, 16%-51%), and unshared environment was responsible for the largest portion (67%; 95% CI, 49%-84%) of the variance. Duration of sports activities was significantly (P < 0.05) related to the magnitude of hepatic vein flow, while other risk factors and lifestyle characteristics had no significant influence. The data suggest that genetic factors have little impact on the parameters of hepatic venous blood flow. The variability observed in healthy twins by the Doppler interrogation can be explained by the effect of unshared environmental components primarily related to regular physical activity. These findings underscore the importance of unique environments in physiological variations of hepatic venous blood flow.
authors.affiliation: Department of Radiology and Oncotherapy, Semmelweis University, Budapest, 1082, Hungary.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Tarnoki
authors.affiliation: Department of Radiology and Oncotherapy, Semmelweis University, Budapest, 1082, Hungary.
authors.forename: David L
authors.initials: DL
authors.lastname: Tarnoki
authors.affiliation: Central European University, Budapest, 1051, Hungary.
authors.forename: Levente
authors.initials: L
authors.lastname: Littvay
authors.affiliation: Houston Methodist DeBakey Heart & Vascular Center, The Houston Methodist Hospital, Houston, TX 77030, USA.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Garami
authors.affiliation: Department of Cardiology, Military Hospital, Budapest, 1134, Hungary.
authors.forename: Andrea Agnes
authors.initials: AA
authors.lastname: Molnar
authors.affiliation: Department of Radiology and Oncotherapy, Semmelweis University, Budapest, 1082, Hungary.
authors.forename: Viktor
authors.initials: V
authors.lastname: Berczi
authors.affiliation: Department of Radiology and Oncotherapy, Semmelweis University, Budapest, 1082, Hungary.
authors.forename: Kinga
authors.initials: K
authors.lastname: Karlinger
authors.affiliation: Department of Medicine, VA Boston Healthcare System and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02130, USA.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Baffy
mesh_terms: D000328:Adult; D004777:Environment; D015444:Exercise; D005260:Female; D006503:Hepatic Veins / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic