title: A role for H2S in the microcirculation of newborns: the major metabolite of H2S (thiosulphate) is increased in preterm infants.
abstract: Excessive vasodilatation during the perinatal period is associated with cardiorespiratory instability in preterm neonates. Little evidence of the mechanisms controlling microvascular tone during circulatory transition exists. We hypothesised that hydrogen sulphide (H2S), an important regulator of microvascular reactivity and central cardiac function in adults and animal models, may contribute to the vasodilatation observed in preterm newborns. Term and preterm neonates (24-43 weeks gestational age) were studied. Peripheral microvascular blood flow was assessed by laser Doppler. Thiosulphate, a urinary metabolite of H2S, was determined by high performance liquid chromatography as a measure of 24 hr total body H2S turnover for the first 3 days of postnatal life. H2S turnover was greatest in very preterm infants and decreased with increasing gestational age (p = 0.0001). H2S turnover was stable across the first 72 hrs of life in older neonates. In very preterm neonates, H2S turnover increased significantly from day 1 to 3 (p =0.0001); and males had higher H2S turnover than females (p = 0.04). A significant relationship between microvascular blood flow and H2S turnover was observed on day 2 of postnatal life (p = 0.0004). H2S may play a role in maintaining microvascular tone in the perinatal period. Neonates at the greatest risk of microvascular dysfunction characterised by inappropriate peripheral vasodilatation--very preterm male neonates--are also the neonates with highest levels of total body H2S turnover suggesting that overproduction of this gasotransmitter may contribute to microvascular dysfunction in preterms. Potentially, H2S is a target to selectively control microvascular tone in the circulation of newborns.
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; Discipline of Paediatrics and Child Health, School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia; Illawarra Health and Medical Research Institute and Graduate School of Medicine, University of Wollongong, Wollongong, NSW, Australia.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Dyson
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Hannah K
authors.initials: HK
authors.lastname: Palliser
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; Discipline of Public Health, School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Latter
authors.affiliation: Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, Lodz, Poland.
authors.forename: Grazyna
authors.initials: G
authors.lastname: Chwatko
authors.affiliation: Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, Lodz, Poland.
authors.forename: Rafal
authors.initials: R
authors.lastname: Glowacki
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; Discipline of Paediatrics and Child Health, School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia; Illawarra Health and Medical Research Institute and Graduate School of Medicine, University of Wollongong, Wollongong, NSW, Australia; Kaleidoscope Neonatal Intensive Care Unit, John Hunter Children's Hospital, New Lambton Heights, NSW, Australia.
authors.forename: Ian M R
authors.initials: IM
authors.lastname: Wright
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism*; D007231:Infant, Newborn; D007234:Infant, Premature; D008833:Microcirculation / Q000502:physiology*
chemical_list: D006862:Hydrogen Sulfide