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tetrahydro biopterine deficiency

Tamir Kanias, Ling Wang, Ashley Lippert, Daniel B Kim-Shapiro, Mark T Gladwin
BACKGROUND: The red blood cell (RBC) endothelial nitric oxide synthase (eNOS) has been shown to regulate intrinsic RBC rheologic properties, such as membrane deformability, suggesting that a functional eNOS could be important in RBC viability and function during storage. This study examines the correlation between RBC eNOS deficiency and the propensity of RBCs to hemolyze under selected stress conditions including prolonged hypothermic storage. STUDY DESIGN AND METHODS: Fresh or stored RBCs from normal and eNOS knockout (KO) mice or from healthy human volunteers were subjected to selected hemolytic stress conditions including mechanical stress hemolysis, osmotic stress hemolysis, and oxidation stress hemolysis and evaluated during standard storage in CPDA-1 solutions...
May 2013: Transfusion
Lila Mayahi, Lydia Mason, Katherine Bleasdale-Barr, Ann Donald, Iris Trender-Gerhard, Mary G Sweeney, Mary B Davis, Nicholas Wood, Christopher J Mathias, Laura Watson, Denis Pellerin, Simon Heales, John E Deanfield, Kailash Bhatia, Judith Murray-Rust, Aroon D Hingorani
BACKGROUND: (6R)-5,6,7,8-Tetrahydro-l-biopterin (BH4) is a cofactor for enzymes involved in catecholamine and nitric oxide generation whose synthesis is initiated by GTP cyclohydrolase I (GTPCH-1), encoded by GCH1. In the absence of a potent, specific GTPCH-1 inhibitor, natural BH4 deficiency caused by mutations in GCH1 in the rare movement disorder, DOPA-responsive dystonia (OMIM DYT5), offers the opportunity to study the role of endogenous BH4 in humans. METHODS AND RESULTS: In 16 DOPA-responsive dystonia patients with mutations predicted to affect GTPCH-1 expression or function and in age- and sex-matched control subjects, we measured plasma biopterin and nitrogen oxides by high-performance liquid chromatography and the Griess reaction, respectively, endothelial function by brachial artery flow-mediated dilation (FMD), sympathetic function by measurement of plasma norepinephrine, epinephrine, and heart rate and blood pressure in response...
December 2010: Circulation. Cardiovascular Genetics
Jian Xu, Shuangxi Wang, Yong Wu, Ping Song, Ming-Hui Zou
The ubiquitin-proteasome system has been implicated in oxidative stress-induced endothelial dysfunction in cardiovascular diseases. However, the mechanism by which oxidative stress alters the ubiquitin-proteasome system is poorly defined. The present study was conducted to determine whether oxidative modifications of PA700, a 26S proteasome regulatory subunit, contributes to angiotensin II (Ang II)-induced endothelial dysfunction. Exposure of human umbilical vein endothelial cells to low concentrations of Ang II, but not vehicle, for 6 hours significantly decreased the levels of tetrahydro-l-biopterin (BH4), an essential cofactor of endothelial NO synthase, which was accompanied by a decrease in GTP cyclohydrolase I, the rate-limiting enzyme for de novo BH4 synthesis...
September 2009: Hypertension
Nicola Longo
Defects in the metabolism or regeneration of tetrahydrobiopterin (BH4) were initially discovered in patients with hyperphenylalaninaemia who had progressive neurological deterioration despite optimal metabolic control (malignant hyperphenylalaninaemia). BH4 is an essential cofactor not only for phenylalanine hydroxylase, but also for tyrosine and two tryptophan hydroxylases, three nitric oxide synthases, and glyceryl-ether monooxygenase. Defective activity of tyrosine and tryptophan hydroxylases explains the neurological deterioration in patients with BH4 deficiency with progressive mental and physical retardation, central hypotonia and peripheral spasticity, seizures and microcephaly...
June 2009: Journal of Inherited Metabolic Disease
Avihu Boneh, Dorothy E M Francis, Maureen Humphrey, Helen J Upton, Heidi L Peters
AIMS: To determine the prevalence, the types and severity of hyperphenylalaninaemia (including phenylketonuria (PKU)) in Victoria and to report on a new treatment modality of PKU. METHODS: We reviewed the medical records of all patients diagnosed with high blood phenylalanine levels by newborn screening between November 2001 and October 2004. RESULTS: We identified 17 newborn babies with high levels of blood phenylalanine (total samples: 190,835)...
September 2006: Journal of Paediatrics and Child Health
Lonneke M Bevers, Branko Braam, Jan Andries Post, Anton Jan van Zonneveld, Ton J Rabelink, Hein A Koomans, Marianne C Verhaar, Jaap A Joles
Endothelial NO synthase (eNOS) produces superoxide when depleted of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) and L-arginine by uncoupling the electron flow from NO production. High expression of eNOS has been reported to have beneficial effects in atherosclerotic arteries after relatively short periods of time. However, sustained high expression of eNOS may have disadvantageous vascular effects because of uncoupling. We investigated NO and reactive oxygen species (ROS) production in a microvascular endothelial cell line (bEnd...
January 2006: Hypertension
F Cosentino, J E Barker, M P Brand, S J Heales, E R Werner, J R Tippins, N West, K M Channon, M Volpe, T F Lüscher
(6R)-5,6,7,8-Tetrahydro-biopterin (H(4)B) is essential for the catalytic activity of all NO synthases. The hyperphenylalaninemic mouse mutant (hph-1) displays 90% deficiency of the GTP cyclohydrolase I, the rate-limiting enzyme in H(4)B synthesis. A relative shortage of H(4)B may shift the balance between endothelial NO synthase (eNOS)-catalyzed generation of NO and reactive oxygen species. Therefore, the hph-1 mouse represents a unique model to assess the effect of chronic H(4)B deficiency on endothelial function...
April 2001: Arteriosclerosis, Thrombosis, and Vascular Biology
Z Tomsová, Z Jůzová
Estimation of neopterin in urine has become part of examination in phenylketonuria, malignities, immunodeficiency incl. AIDS and HIV infection. The authors describe a simple chromatographic method for estimation of neopterin which does not call for highly efficient liquid chromatography nor imported kits. The di- and tetrahydro- forms of neopterin are oxidized with MnO2 and stable neopterin is obtained. The specimen is purified on a Dowex 50WX4 (Fluka) column in a H+ cycle and on PRESEPC18 (TESSEK) columns...
January 6, 1989: Casopís Lékar̆ů C̆eských
A D Kay, S Milstien, S Kaufman, H Creasey, J V Haxby, N R Cutler, S I Rapoport
Tetrahydrobiopterin is the cofactor in the hydroxylation of phenylalanine, tyrosine, and tryptophan leading to the eventual synthesis of the monoaminergic neurotransmitters, dopamine, norepinephrine, and serotonin, respectively. Total biopterin (90% of which is in the tetrahydro form) was measured in cerebrospinal fluid (CSF) and plasma of 30 patients with Alzheimer's disease and of 19 healthy controls. Plasma and CSF biopterin concentrations were not significantly correlated, but the mean CSF biopterin concentration in patients with Alzheimer's disease was significantly less than in age-matched controls, 13...
October 1986: Archives of Neurology
H C Curtius, A Matasovic, G Schoedon, T Kuster, P Guibaud, T Giudici, N Blau
Three novel pteridines have been isolated from the urine of patients with a new variant of 6-(L-erythro-1',2'-dihydroxypropyl)-5,6,7,8-tetrahydropterin (tetrahydrobiopterin) deficiency, showing hyperphenylalaninemia. From the results of high performance liquid chromatography, oxidative degradation, and gas chromatography-electron impact mass spectrometry, their structures were identified as 7-(D-erythro-1',2',3'-trihydroxypropyl)-pterin (7-neopterin), 7-(L-erythro-1',2'-dihydroxypropyl)-pterin (7-biopterin), and 6-oxo-7-(L-erythro-1',2'-dihydroxypropyl)-pterin (6-oxo-7-biopterin)...
March 5, 1990: Journal of Biological Chemistry
C Adler, S Ghisla, I Rebrin, C W Heizmann, N Blau, H C Curtius
No abstract text is available yet for this article.
1992: Journal of Inherited Metabolic Disease
C Adler, S Ghisla, I Rebrin, J Haavik, C W Heizmann, N Blau, T Kuster, H C Curtius
A recently described new form of hyperphenylalaninemia is characterized by the excretion of 7-substituted isomers of biopterin and neopterin and 7-oxo-biopterin in the urine of patients. It has been shown that the 7-substituted isomers of biopterin and neopterin derive from L-tetrahydrobiopterin and D-tetrahydroneopterin and are formed during hydroxylation of phenylalanine to tyrosine with rat liver dehydratase-free phenylalanine hydroxylase. We have now obtained identical results using human phenylalanine hydroxylase...
August 15, 1992: European Journal of Biochemistry
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