1
|
Shyam R, Sekhar Panda H, Mishra J, Jyoti Panda J, Kour A. Emerging biosensors in Phenylketonuria. Clin Chim Acta 2024; 559:119725. [PMID: 38734223 DOI: 10.1016/j.cca.2024.119725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Phenylketonuria (PKU) is an autosomal recessive metabolic disorder resulting from deficient phenylalanine hydroxylase (PAH) enzyme activity, leading to impaired phenylalanine (Phe) metabolism. This condition can lead to intellectual disability, epilepsy, and behavioural issues. Treatment typically involves strict dietary restrictions on natural protein intake, supplemented with chemically manufactured protein substitutes containing amino acids other than Phe. Various approaches, including casein glycomacropeptide (GMP), tetrahydrobiopterin (BH4), phenylalanine ammonia-lyase (PAL) therapy, large neutral amino acid (LNAA) supplementation, enzyme therapy, gene therapy, and medical therapies, aim to prevent Phe transport in the brain to potentially treat PKU. Although newborn screening programs and early dietary interventions have enhanced outcomes of the potential treatment strategies, limitations still persist in this direction. These involve potent accuracy concerns in diagnosis due to the existence of antibiotics in blood of PKU patients, affecting growth of the bacteria in the bacterial inhibition assay. Monitoring involves complex methods for instance, mass spectrometry and high-pressure liquid chromatography, which involve shortcomings such as lengthy protocols and the need for specialized equipment. To address these limitations, adaptable testing formats like bio/nano sensors are emerging with their cost-effectiveness, biodegradability, and rapid, accurate, and sensitive detection capabilities, offering promising alternatives for PKU diagnosis. This review provides insights into current treatment and diagnostic approaches, emphasizing on the potential applications of the diverse sensors intended for PKU diagnosis.
Collapse
Affiliation(s)
- Ritika Shyam
- University Institute of Pharma Sciences, Chandigarh University, Gharuan, Mohali, Punjab 140413, India
| | | | - Jibanananda Mishra
- School of Biosciences, RIMT University, Mandi Gobindgarh, Punjab 147301, India
| | - Jiban Jyoti Panda
- Institute of Nanoscience and Technology, Mohali, Punjab 140306, India.
| | - Avneet Kour
- University Institute of Pharma Sciences, Chandigarh University, Gharuan, Mohali, Punjab 140413, India.
| |
Collapse
|
2
|
Cronin SJF, Andrews NA, Latremoliere A. Peripheralized sepiapterin reductase inhibition as a safe analgesic therapy. Front Pharmacol 2023; 14:1173599. [PMID: 37251335 PMCID: PMC10213231 DOI: 10.3389/fphar.2023.1173599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023] Open
Abstract
The development of novel analgesics for chronic pain in the last 2 decades has proven virtually intractable, typically failing due to lack of efficacy and dose-limiting side effects. Identified through unbiased gene expression profiling experiments in rats and confirmed by human genome-wide association studies, the role of excessive tetrahydrobiopterin (BH4) in chronic pain has been validated by numerous clinical and preclinical studies. BH4 is an essential cofactor for aromatic amino acid hydroxylases, nitric oxide synthases, and alkylglycerol monooxygenase so a lack of BH4 leads to a range of symptoms in the periphery and central nervous system (CNS). An ideal therapeutic goal therefore would be to block excessive BH4 production, while preventing potential BH4 rundown. In this review, we make the case that sepiapterin reductase (SPR) inhibition restricted to the periphery (i.e., excluded from the spinal cord and brain), is an efficacious and safe target to alleviate chronic pain. First, we describe how different cell types that engage in BH4 overproduction and contribute to pain hypersensitivity, are themselves restricted to peripheral tissues and show their blockade is sufficient to alleviate pain. We discuss the likely safety profile of peripherally restricted SPR inhibition based on human genetic data, the biochemical alternate routes of BH4 production in various tissues and species, and the potential pitfalls to predictive translation when using rodents. Finally, we propose and discuss possible formulation and molecular strategies to achieve peripherally restricted, potent SPR inhibition to treat not only chronic pain but other conditions where excessive BH4 has been demonstrated to be pathological.
Collapse
Affiliation(s)
| | - Nick A. Andrews
- The Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Alban Latremoliere
- Departments of Neurosurgery and Neuroscience, Johns Hopkins School of Medicine, Neurosurgery Pain Research Institute, Baltimore, MD, United States
| |
Collapse
|
3
|
Cannon Homaei S, Barone H, Kleppe R, Betari N, Reif A, Haavik J. ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications. Neurosci Biobehav Rev 2021; 132:838-856. [PMID: 34774900 DOI: 10.1016/j.neubiorev.2021.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 12/16/2022]
Abstract
Neurometabolic diseases (NMDs) are typically caused by genetic abnormalities affecting enzyme functions, which in turn interfere with normal development and activity of the nervous system. Although the individual disorders are rare, NMDs are collectively relatively common and often lead to lifelong difficulties and high societal costs. Neuropsychiatric manifestations, including ADHD symptoms, are prominent in many NMDs, also when the primary biochemical defect originates in cells and tissues outside the nervous system. ADHD symptoms have been described in phenylketonuria, tyrosinemias, alkaptonuria, succinic semialdehyde dehydrogenase deficiency, X-linked ichthyosis, maple syrup urine disease, and several mitochondrial disorders, but are probably present in many other NMDs and may pose diagnostic and therapeutic challenges. Here we review current literature linking NMDs with ADHD symptoms. We cite emerging evidence that many NMDs converge on common neurochemical mechanisms that interfere with monoamine neurotransmitter synthesis, transport, metabolism, or receptor functions, mechanisms that are also considered central in ADHD pathophysiology and treatment. Finally, we discuss the therapeutic implications of these findings and propose a path forward to increase our understanding of these relationships.
Collapse
Affiliation(s)
- Selina Cannon Homaei
- Division of Psychiatry, Haukeland University Hospital, Norway; Department of Biomedicine, University of Bergen, Norway.
| | - Helene Barone
- Regional Resource Center for Autism, ADHD, Tourette Syndrome and Narcolepsy, Western Norway, Division of Psychiatry, Haukeland University Hospital, Norway.
| | - Rune Kleppe
- Division of Psychiatry, Haukeland University Hospital, Norway; Norwegian Centre for Maritime and Diving Medicine, Department of Occupational Medicine, Haukeland University Hospital, Norway.
| | - Nibal Betari
- Department of Biomedicine, University of Bergen, Norway.
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
| | - Jan Haavik
- Division of Psychiatry, Haukeland University Hospital, Norway; Department of Biomedicine, University of Bergen, Norway.
| |
Collapse
|
4
|
Opladen T, López-Laso E, Cortès-Saladelafont E, Pearson TS, Sivri HS, Yildiz Y, Assmann B, Kurian MA, Leuzzi V, Heales S, Pope S, Porta F, García-Cazorla A, Honzík T, Pons R, Regal L, Goez H, Artuch R, Hoffmann GF, Horvath G, Thöny B, Scholl-Bürgi S, Burlina A, Verbeek MM, Mastrangelo M, Friedman J, Wassenberg T, Jeltsch K, Kulhánek J, Kuseyri Hübschmann O. Consensus guideline for the diagnosis and treatment of tetrahydrobiopterin (BH 4) deficiencies. Orphanet J Rare Dis 2020; 15:126. [PMID: 32456656 PMCID: PMC7251883 DOI: 10.1186/s13023-020-01379-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/07/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Tetrahydrobiopterin (BH4) deficiencies comprise a group of six rare neurometabolic disorders characterized by insufficient synthesis of the monoamine neurotransmitters dopamine and serotonin due to a disturbance of BH4 biosynthesis or recycling. Hyperphenylalaninemia (HPA) is the first diagnostic hallmark for most BH4 deficiencies, apart from autosomal dominant guanosine triphosphate cyclohydrolase I deficiency and sepiapterin reductase deficiency. Early supplementation of neurotransmitter precursors and where appropriate, treatment of HPA results in significant improvement of motor and cognitive function. Management approaches differ across the world and therefore these guidelines have been developed aiming to harmonize and optimize patient care. Representatives of the International Working Group on Neurotransmitter related Disorders (iNTD) developed the guidelines according to the SIGN (Scottish Intercollegiate Guidelines Network) methodology by evaluating all available evidence for the diagnosis and treatment of BH4 deficiencies. CONCLUSION Although the total body of evidence in the literature was mainly rated as low or very low, these consensus guidelines will help to harmonize clinical practice and to standardize and improve care for BH4 deficient patients.
Collapse
Affiliation(s)
- Thomas Opladen
- Division of Child Neurology and Metabolic Disorders, University Children's Hospital, Heidelberg, Germany.
| | - Eduardo López-Laso
- Pediatric Neurology Unit, Department of Pediatrics, University Hospital Reina Sofía, IMIBIC and CIBERER, Córdoba, Spain
| | - Elisenda Cortès-Saladelafont
- Inborn errors of metabolism Unit, Institut de Recerca Sant Joan de Déu and CIBERER-ISCIII, Barcelona, Spain
- Unit of Pediatric Neurology and Metabolic Disorders, Department of Pediatrics, Hospital Germans Trias i Pujol, and Faculty of Medicine, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Toni S Pearson
- Department of Neurology, Washington University School of Medicine, St. Louis, USA
| | - H Serap Sivri
- Department of Pediatrics, Section of Metabolism, Hacettepe University, Faculty of Medicine, 06100, Ankara, Turkey
| | - Yilmaz Yildiz
- Department of Pediatrics, Section of Metabolism, Hacettepe University, Faculty of Medicine, 06100, Ankara, Turkey
| | - Birgit Assmann
- Division of Child Neurology and Metabolic Disorders, University Children's Hospital, Heidelberg, Germany
| | - Manju A Kurian
- Developmental Neurosciences, UCL Great Ormond Street-Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Vincenzo Leuzzi
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Simon Heales
- Neurometabolic Unit, National Hospital, Queen Square, London, UK
| | - Simon Pope
- Neurometabolic Unit, National Hospital, Queen Square, London, UK
| | - Francesco Porta
- Department of Pediatrics, AOU Città della Salute e della Scienza, Torino, Italy
| | - Angeles García-Cazorla
- Inborn errors of metabolism Unit, Institut de Recerca Sant Joan de Déu and CIBERER-ISCIII, Barcelona, Spain
| | - Tomáš Honzík
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Roser Pons
- First Department of Pediatrics of the University of Athens, Aghia Sofia Hospital, Athens, Greece
| | - Luc Regal
- Department of Pediatric, Pediatric Neurology and Metabolism Unit, UZ Brussel, Brussels, Belgium
| | - Helly Goez
- Department of Pediatrics, University of Alberta Glenrose Rehabilitation Hospital, Edmonton, Canada
| | - Rafael Artuch
- Clinical biochemistry department, Institut de Recerca Sant Joan de Déu, CIBERER and MetabERN Hospital Sant Joan de Déu, Barcelona, Spain
| | - Georg F Hoffmann
- Division of Child Neurology and Metabolic Disorders, University Children's Hospital, Heidelberg, Germany
| | - Gabriella Horvath
- Department of Pediatrics, Division of Biochemical Genetics, BC Children's Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital Zurich, Zürich, Switzerland
| | - Sabine Scholl-Bürgi
- Clinic for Pediatrics I, Medical University of Innsbruck, Anichstr 35, Innsbruck, Austria
| | - Alberto Burlina
- U.O.C. Malattie Metaboliche Ereditarie, Dipartimento della Salute della Donna e del Bambino, Azienda Ospedaliera Universitaria di Padova - Campus Biomedico Pietro d'Abano, Padova, Italy
| | - Marcel M Verbeek
- Departments of Neurology and Laboratory Medicine, Alzheimer Centre, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Mario Mastrangelo
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Jennifer Friedman
- UCSD Departments of Neuroscience and Pediatrics, Rady Children's Hospital Division of Neurology; Rady Children's Institute for Genomic Medicine, San Diego, USA
| | - Tessa Wassenberg
- Department of Pediatric, Pediatric Neurology and Metabolism Unit, UZ Brussel, Brussels, Belgium
| | - Kathrin Jeltsch
- Division of Child Neurology and Metabolic Disorders, University Children's Hospital, Heidelberg, Germany
| | - Jan Kulhánek
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
| | - Oya Kuseyri Hübschmann
- Division of Child Neurology and Metabolic Disorders, University Children's Hospital, Heidelberg, Germany
| |
Collapse
|
5
|
Arning E, Bottiglieri T. LC-MS/MS Analysis of Cerebrospinal Fluid Metabolites in the Pterin Biosynthetic Pathway. JIMD Rep 2014; 29:1-9. [PMID: 25213568 PMCID: PMC5059177 DOI: 10.1007/8904_2014_336] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/18/2014] [Accepted: 07/01/2014] [Indexed: 12/12/2022] Open
Abstract
The analysis of (6R)-5,6,7,8-tetrahydrobiopterin (BH4) and neopterin in cerebrospinal fluid (CSF) is often used to identify defects in the pterin biosynthetic pathway affecting monoamine metabolism that can lead to pediatric neurotransmitter diseases. Low levels of BH4 and neopterin alone may not be sufficient to determine the defect, and further testing is often required. We have developed a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for determination of BH4, 7,8-dihydrobiopterin (BH2), neopterin, and sepiapterin in CSF, which provides a more comprehensive evaluation of the pterin pathway. The method utilizes labeled stable isotopes as internal standards and allows for a fast 10-minute analysis by LC/MS/MS over a linear working range of 3 to 200 nmol/L. Total analytical imprecision is less than 14.4% for all pterin metabolites. Accuracy for BH4 and neopterin was determined by comparing data obtained by an alternative method using HPLC with EC and fluorescence detection. Excellent correlation was demonstrated for BH4 (r = 0.9646, 1/slope = 0.9397; n = 28; concentration range 3 to 63 nmol/L) and neopterin (r = 0.9919, 1/slope = 0.9539; n = 13; concentration range 5 to 240 nmol/L). CSF specimens from patients diagnosed with inborn errors of sepiapterin reductase (SR), 6-pyruvoyl-tetrahydropterin synthase (PTPS), dihydropteridine reductase (DHPR), and guanosine triphosphate cyclohydrolase (GTPCH) have been analyzed, and distinct pterin metabolite patterns were consistent with the initial diagnosis. This method differentiates patients with DHPR and SR deficiency from other pterin defects (GTPCH and PTPS) and will be useful for the diagnosis of specific defects in the pterin biosynthetic pathway.
Collapse
Affiliation(s)
- Erland Arning
- Baylor Research Institute, Institute of Metabolic Disease, Dallas, TX, 75226, USA.
| | - Teodoro Bottiglieri
- Baylor Research Institute, Institute of Metabolic Disease, Dallas, TX, 75226, USA
| |
Collapse
|
6
|
Does Restraining Nitric Oxide Biosynthesis Rescue from Toxins-Induced Parkinsonism and Sporadic Parkinson's Disease? Mol Neurobiol 2013; 49:262-75. [DOI: 10.1007/s12035-013-8517-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/16/2013] [Indexed: 12/21/2022]
|
7
|
Kapatos G. The neurobiology of tetrahydrobiopterin biosynthesis: a model for regulation of GTP cyclohydrolase I gene transcription within nigrostriatal dopamine neurons. IUBMB Life 2013; 65:323-33. [PMID: 23457032 DOI: 10.1002/iub.1140] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/07/2013] [Indexed: 12/31/2022]
Abstract
Within the brain, the reduced pteridine cofactor 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4) is absolutely required for the synthesis of the monoamine (MA) neurotransmitters dopamine (DA), norepinephrine, epinephrine (E), and serotonin (5-HT), the novel gaseous neurotransmitter nitric oxide and the production of yet to be identified 1-O-alkylglycerol-derived lipids. GTP cyclohydrolase I (GTPCH) catalyzes the first and limiting step in the BH4 biosynthetic pathway, which is now thought to involve up to eight different proteins supporting six alternate de novo and two alternate salvage pathways. Gene expression analysis across different regions of the human brain shows the abundance of transcripts coding for all eight of these proteins to be highly correlated with each other and to be enriched within human MA neurons. The potential for multiple routes for BH4 synthesis therefore exists within the human brain. GTPCH expression is particularly heterogeneous across different populations of human and rodent MA-containing neurons, with low expression levels and therefore BH4 being a characteristic of nigrostriatal DA (NSDA) neurons. Basic knowledge of how GCH1 gene transcription is controlled within NSDA neurons may explain the distinctive susceptibility of these neurons to human genetic mutations that result in BH4 deficiency. A model for cyclic adenosine monophosphate-dependent GCH1 transcription is described that involves a unique combination of DNA regulatory sequences and transcription factors. This model proposes that low levels of GCH1 transcription within NSDA neurons are driven by their distinctive physiology, suggesting that pharmacological manipulation of GCH1 gene transcription can be used to modify BH4 levels and therefore DA synthesis in the basal ganglia.
Collapse
Affiliation(s)
- Gregory Kapatos
- Department of Pharmacology, Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| |
Collapse
|
8
|
Friedman J, Roze E, Abdenur JE, Chang R, Gasperini S, Saletti V, Wali GM, Eiroa H, Neville B, Felice A, Parascandalo R, Zafeiriou DI, Arrabal-Fernandez L, Dill P, Eichler FS, Echenne B, Gutierrez-Solana LG, Hoffmann GF, Hyland K, Kusmierska K, Tijssen MAJ, Lutz T, Mazzuca M, Penzien J, Poll-The BT, Sykut-Cegielska J, Szymanska K, Thöny B, Blau N. Sepiapterin reductase deficiency: a treatable mimic of cerebral palsy. Ann Neurol 2012; 71:520-30. [PMID: 22522443 DOI: 10.1002/ana.22685] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Sepiapterin reductase deficiency (SRD) is an under-recognized levodopa-responsive disorder. We describe clinical, biochemical, and molecular findings in a cohort of patients with this treatable condition. We aim to improve awareness of the phenotype and available diagnostic and therapeutic strategies to reduce delayed diagnosis or misdiagnosis, optimize management, and improve understanding of pathophysiologic mechanisms. METHODS Forty-three individuals with SRD were identified from 23 international medical centers. The phenotype and treatment response were assessed by chart review using a detailed standardized instrument and by literature review for cases for which records were unavailable. RESULTS In most cases, motor and language delays, axial hypotonia, dystonia, weakness, oculogyric crises, and diurnal fluctuation of symptoms with sleep benefit become evident in infancy or childhood. Average age of onset is 7 months, with delay to diagnosis of 9.1 years. Misdiagnoses of cerebral palsy (CP) are common. Most patients benefit dramatically from levodopa/carbidopa, often with further improvement with the addition of 5-hydroxytryptophan. Cerebrospinal fluid findings are distinctive. Diagnosis is confirmed by mutation analysis and/or enzyme activity measurement in cultured fibroblasts. INTERPRETATION Common, clinical findings of SRD, aside from oculogyric crises and diurnal fluctuation, are nonspecific and mimic CP with hypotonia or dystonia. Patients usually improve dramatically with treatment. Consequently, we recommend consideration of SRD not only in patients with levodopa-responsive motor disorders, but also in patients with developmental delays with axial hypotonia, and patients with unexplained or atypical presumed CP. Biochemical investigation of cerebrospinal fluid is the preferred method of initial investigation. Early diagnosis and treatment are recommended to prevent ongoing brain dysfunction.
Collapse
Affiliation(s)
- Jennifer Friedman
- Departments of Neurosciences and Pediatrics, University of California at San Diego and Rady Children's Hospital, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Blau N, Hennermann JB, Langenbeck U, Lichter-Konecki U. Diagnosis, classification, and genetics of phenylketonuria and tetrahydrobiopterin (BH4) deficiencies. Mol Genet Metab 2011; 104 Suppl:S2-9. [PMID: 21937252 DOI: 10.1016/j.ymgme.2011.08.017] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/17/2011] [Accepted: 08/17/2011] [Indexed: 11/29/2022]
Abstract
This article summarizes the present knowledge, recent developments, and common pitfalls in the diagnosis, classification, and genetics of hyperphenylalaninemia, including tetrahydrobiopterin (BH4) deficiency. It is a product of the recent workshop organized by the European Phenylketonuria Group in March 2011 in Lisbon, Portugal. Results of the workshop demonstrate that following newborn screening for phenylketonuria (PKU), using tandem mass-spectrometry, every newborn with even slightly elevated blood phenylalanine (Phe) levels needs to be screened for BH4 deficiency. Dried blood spots are the best sample for the simultaneous measurement of amino acids (phenylalanine and tyrosine), pterins (neopterin and biopterin), and dihydropteridine reductase activity from a single specimen. Following diagnosis, the patient's phenotype and individually tailored treatment should be established as soon as possible. Not only blood Phe levels, but also daily tolerance for dietary Phe and potential responsiveness to BH4 are part of the investigations. Efficiency testing with synthetic BH4 (sapropterin dihydrochloride) over several weeks should follow the initial 24-48-hour screening test with 20mg/kg/day BH4. The specific genotype, i.e. the combination of both PAH alleles of the patient, helps or facilitates to determine both the biochemical phenotype (severity of PKU) and the responsiveness to BH4. The rate of Phe metabolic disposal after Phe challenge may be an additional useful tool in the interpretation of phenotype-genotype correlation.
Collapse
Affiliation(s)
- Nenad Blau
- University Children's Hospital, Zürich, Switzerland.
| | | | | | | |
Collapse
|
10
|
Opladen T, Abu Seda B, Rassi A, Thöny B, Hoffmann GF, Blau N. Diagnosis of tetrahydrobiopterin deficiency using filter paper blood spots: further development of the method and 5 years experience. J Inherit Metab Dis 2011; 34:819-26. [PMID: 21416196 DOI: 10.1007/s10545-011-9300-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 02/09/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
Abstract
In every newborn with even mild hyperphenylalaninemia (HPA) tetrahydrobiopterin (BH(4)) deficiencies need to be excluded as soon as possible. Differential diagnosis is most commonly performed by analysis of urinary neopterin and biopterin. In 2005 a new method for the measurement of neopterin, biopterin and other pterins in dried blood spot (DBS) on filter paper was introduced. In order to evaluate the usefulness of this method as a standard tool for differential diagnosis of HPAs we analyzed neopterin, biopterin, pterin and dihydropteridine reductase activity in DBS from 362 patients with HPA over the period of five years. Age-dependent reference values were established for the HPA population. Sixty-four patients with BH(4) deficiency (27 patients with 6-pyruvoyl-tetrahydropterin synthase deficiency, seven with GTP cyclohydrolase I deficiency, and 30 with dihydropteridine reductase) were identified. Reference values for neopterin and biopterin in DBS were calculated for each of the variants. 6-pyruvoyl-tetrahydropterin synthase and GTP cyclohydrolase I deficiency can be diagnosed by neopterin and biopterin analysis alone, while for diagnosis of dihydropteridine reductase deficiency additional determination of enzyme activity from the same DBS is essential. Regarding test sensitivity, the interpretation of neopterin and biopterin concentration per hemoglobin is more valid than the interpretation of neopterin and biopterin per liter. Percentage of biopterin, of the sum of neopterin and biopterin should always be calculated. In addition, determination of hemoglobin concentration is essential as a measure for efficient extraction of neopterin and biopterin. Although the measurement of neopterin and biopterin in urine is more sensitive due to the higher concentrations present, our data prove the usefulness of their measurement from DBS for the routine diagnosis of BH(4) deficiencies.
Collapse
Affiliation(s)
- Thomas Opladen
- Division of Inborn Metabolic Diseases, University Children's Hospital Heidelberg, Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
11
|
Sumi-Ichinose C, Ichinose H, Ikemoto K, Nomura T, Kondo K. Advanced Research on Dopamine Signaling to Develop Drugs for the Treatment of Mental Disorders: Regulation of Dopaminergic Neural Transmission by Tyrosine Hydroxylase Protein at Nerve Terminals. J Pharmacol Sci 2010; 114:17-24. [DOI: 10.1254/jphs.09r28fm] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
12
|
Verbeek MM, Willemsen MAAP, Wevers RA, Lagerwerf AJ, Abeling NGGM, Blau N, Thöny B, Vargiami E, Zafeiriou DI. Two Greek siblings with sepiapterin reductase deficiency. Mol Genet Metab 2008; 94:403-409. [PMID: 18502672 DOI: 10.1016/j.ymgme.2008.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 04/04/2008] [Accepted: 04/04/2008] [Indexed: 11/18/2022]
Abstract
BACKGROUND Sepiapterin reductase (SR) deficiency is a rare inherited disorder of neurotransmitter metabolism; less than 25 cases have been described in the literature so far. METHODS We describe the clinical history and extensive cerebrospinal fluid (CSF) and urine examination of two Greek siblings with the diagnosis of SR deficiency. The diagnosis was confirmed by enzyme activity measurement in cultured fibroblasts and by mutation analysis. RESULTS Both patients suffered from a progressive and complex L-dopa responsive movement disorder. Very low concentrations of the neurotransmitter metabolites homovanillic acid (HVA), 5-hydroxyindolacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) were observed in CSF. CSF neopterin and biopterin concentrations were abnormal in one case only, whereas in both cases sepiapterin concentrations were abnormally high and 5-hydroxytryptophan was undetectable. Urine concentrations of HVA, 5-HIAA and vanillyl mandelic acid (VMA) were decreased in both cases. Both patients had no detectable SR enzyme activity in primary dermal fibroblasts, and upon analysis of genomic DNA revealed the same homozygous point mutation introducing a premature stop codon into the reading frame of the SPR gene (mutant allele K251X). CONCLUSIONS Our cases illustrate that, apart from HVA and 5-HIAA analysis, the specific quantification of sepiapterin in CSF, rather than neopterin and biopterin alone, is crucial to the final diagnosis of SR deficiency. In addition, urinary concentrations of neurotransmitter metabolites may be abnormal in SR deficiency and may provide an initial indication of SR deficiency before CSF analysis is performed. The known, impressive beneficial response of SR deficient patients to treatment with L-dopa, is illustrated again in our cases.
Collapse
Affiliation(s)
- Marcel M Verbeek
- Department of Neurology, Laboratory of Pediatrics and Neurology, 830 LKN, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Donders Centre for Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Michel A A P Willemsen
- Department of Pediatric Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Donders Centre for Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Ron A Wevers
- Department of Neurology, Laboratory of Pediatrics and Neurology, 830 LKN, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Donders Centre for Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Aart J Lagerwerf
- Department of Neurology, Laboratory of Pediatrics and Neurology, 830 LKN, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Nico G G M Abeling
- Academic Medical Center, Laboratory Genetic Metabolic Diseases, University of Amsterdam, The Netherlands
| | - Nenad Blau
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital Zürich, Switzerland
| | - Beat Thöny
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital Zürich, Switzerland
| | - Euthymia Vargiami
- 1st Department of Pediatrics, Aristotle University of Thessaloniki, Greece
| | | |
Collapse
|
13
|
Wolfarth B, Rankinen T, Mühlbauer S, Ducke M, Rauramaa R, Boulay MR, Pérusse L, Bouchard C. Endothelial nitric oxide synthase gene polymorphism and elite endurance athlete status: the Genathlete study. Scand J Med Sci Sports 2007; 18:485-90. [PMID: 18067521 DOI: 10.1111/j.1600-0838.2007.00717.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the Genathlete study, we examined the contribution of three polymorphisms in the endothelial nitric oxide synthase (NOS3) gene to discriminate elite endurance athletes (EEA) from sedentary controls (SC). The EEA group included a total of 316 Caucasian males with a VO2max >75 mL/kg. The SC group comprised 299 unrelated sedentary Caucasian males who had VO2max values below 50 mL/kg. The polymerase chain reaction technique was used to amplify a microsatellite (CA)(n) repeat in intron 13, a 27 bp repeat in intron 4 and a third fragment in exon 7 containing the Glu298Asp SNP. No difference was found between the EEA and SC groups for the 27 bp repeat and the Glu298Asp polymorphism. Chi-square analysis of the overall allelic distribution of the (CA)(n) repeat revealed no significant difference between the two groups (P=0.135). However, comparing carriers and non-carriers for the most common (CA)(n) repeat alleles, we found significant differences between SC and EEA, with more EEA subjects carrying the 164 bp allele (P=0.007). In summary, we found suggestive evidence that the 164 bp allele of the (CA)(n) repeat in intron 13 is associated with EEA status and may account for some of the differences between EEA and SC.
Collapse
Affiliation(s)
- B Wolfarth
- Department of Preventive and Rehabilitative Sports Medicine, Technical University Munich, Munich, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Foxton RH, Land JM, Heales SJR. Tetrahydrobiopterin availability in Parkinson's and Alzheimer's disease; potential pathogenic mechanisms. Neurochem Res 2007; 32:751-6. [PMID: 17191137 DOI: 10.1007/s11064-006-9201-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Accepted: 10/11/2006] [Indexed: 10/23/2022]
Abstract
Within the central nervous system, tetrahydrobiopterin (BH4) is an essential cofactor for dopamine and serotonin synthesis. In addition, BH4 is now established to be an essential cofactor for all isoforms of nitric oxide synthase (NOS). Inborn errors of metabolism affecting BH4 availability are well documented and the clinical presentation can be attributed to a paucity of dopamine, serotonin, and nitric oxide (NO) generation. In this article, we have focussed upon the sensitivity of BH4 to oxidative catabolism and the observation that when BH4 is limiting some cellular sources of NOS may generate superoxide whilst other BH4 saturated NOS enzymes may be generating NO. Such a scenario could favor peroxynitrite generation. If peroxynitrite is not scavenged, e.g., by antioxidants such as reduced glutathione, irreversible damage to critical cellular enzymes could ensue. Such targets include components of the mitochondrial electron transport chain, alpha ketoglutarate dehydrogenase and possibly pyruvate dehydrogenase. Such a cascade of events is hypothesized, in this article, to occur in neurodegenerative conditions such as Parkinson's and Alzheimer's disease.
Collapse
Affiliation(s)
- Richard H Foxton
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | | | | |
Collapse
|
15
|
Lam AAJ, Hyland K, Heales SJR. Tetrahydrobiopterin availability, nitric oxide metabolism and glutathione status in the hph-1 mouse; implications for the pathogenesis and treatment of tetrahydrobiopterin deficiency states. J Inherit Metab Dis 2007; 30:256-62. [PMID: 17242981 DOI: 10.1007/s10545-006-0502-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 12/13/2006] [Accepted: 12/18/2006] [Indexed: 01/23/2023]
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor for all isoforms of nitric oxide synthase. While it is well established that BH4 deficiency states are associated with impairment of dopamine, serotonin and phenylalanine metabolism, less is known with regard to the effects of deficiency of the cofactor upon nitric oxide (NO) metabolism. In this study, we have evaluated the effects of partial BH4 deficiency upon (a) tissue availability of the antioxidant glutathione, (b) basal NO production and (c) NO generation following exposure to lipopolysaccharide (LPS), which is known to increase expression of the inducible form of nitric oxide synthase. Using the hph-1 mouse, which displays a partial BH4 deficiency owing to impaired activity of GTP cyclohydrolase, we report decreased levels of glutathione in brain and kidney and evidence for decreased basal generation of nitric oxide in the periphery (as judged by the plasma nitrate plus nitrite concentration). Following LPS administration, peripheral NO generation increases. However, the concentration of plasma nitrate plus nitrite achieved was significantly decreased in the hph-1 mouse. Furthermore, LPS administration caused loss of glutathione in both wild-type and hph-1 liver and kidney. It is concluded that cofactor replacement, sufficient to fully correct a cellular BH4 deficiency, may be of benefit to patients with inborn errors of BH4 metabolism.
Collapse
Affiliation(s)
- A A J Lam
- Department of Molecular Neuroscience, Institute of Neurology, London, UK
| | | | | |
Collapse
|
16
|
Van Hove JLK, Steyaert J, Matthijs G, Legius E, Theys P, Wevers R, Romstad A, Møller LB, Hedrich K, Goriounov D, Blau N, Klein C, Casaer P. Expanded motor and psychiatric phenotype in autosomal dominant Segawa syndrome due to GTP cyclohydrolase deficiency. J Neurol Neurosurg Psychiatry 2006; 77:18-23. [PMID: 16361586 PMCID: PMC2117403 DOI: 10.1136/jnnp.2004.051664] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 03/14/2005] [Accepted: 04/14/2005] [Indexed: 11/04/2022]
Abstract
BACKGROUND Segawa syndrome due to GTP cyclohydrolase deficiency is an autosomal dominant disorder with variable expression, that is clinically characterised by l-dopa responsive, diurnally fluctuating dystonia and parkinsonian symptoms. OBJECTIVE To delineate the neurological and psychiatric phenotype in all affected individuals of three extended families. METHODS GTP cyclohydrolase deficiency was documented by biochemical analyses, enzymatic measurements in fibroblasts, and molecular investigations. All affected individuals were examined neurologically, and psychiatric data were systematically reviewed. RESULTS Eighteen affected patients from three families with proven GTP cyclohydrolase deficiency were identified. Eight patients presenting at less than 20 years of age had typical motor symptoms of dystonia with diurnal variation. Five family members had late-presenting mild dopa-responsive symptoms of rigidity, frequent falls, and tendonitis. Among mutation carriers older than 20 years of age, major depressive disorder, often recurrent, and obsessive-compulsive disorder were strikingly more frequent than observed in the general population. Patients responded well to medication increasing serotonergic neurotransmission and to l-dopa substitution. Sleep disorders including difficulty in sleep onset and maintenance, excessive sleepiness, and frequent disturbing nightmares were present in 55% of patients. CONCLUSION Physicians should be aware of this expanded phenotype in affected members of families with GTP cyclohydrolase deficiency.
Collapse
Affiliation(s)
- J L K Van Hove
- Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Zhang Y, Pang T, Earl J, Schyvens CG, McKenzie KUS, Whitworth JA. Role of tetrahydrobiopterin in adrenocorticotropic hormone-induced hypertension in the rat. Clin Exp Hypertens 2004; 26:231-41. [PMID: 15132301 DOI: 10.1081/ceh-120030232] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Adrenocorticotropic hormone (ACTH)-induced hypertension in the rat is characterized by nitric oxide deficiency. Tetrahydrobiopterin (BH4) is an essential cofactor for the enzyme nitric oxide synthase and glucocorticoids have been reported to reduce cytokine-induced BH4 production. Accordingly we hypothesized that ACTH-induced hypertension would be reversed by BH4 supplementation. Male Sprague-Dawley rats (n = 33) were treated with BH4 in vehicle (10 mg/kg/day i.p.) or vehicle alone (5 mg/kg/day i.p. of ascorbic acid in 4 mM HCl) for 10 days. ACTH (0.2 mg/kg s.c.) or saline daily injection was started 2 days after BH4 or vehicle treatment and continued for 8 days. Systolic blood pressure (SBP) was measured on alternate days using the tail cuff method. Treatment with HCl, ascorbic acid or BH4 alone had no effect on SBP. In saline treated rats, neither BH4 nor its vehicle modified SBP. In ACTH treated rats, SBP was increased in both BH4 (from 128 +/- 6 to 142 +/- 4 mmHg, T0 to T10, P < 0.0005, one way ANOVA) and vehicle groups (from 127 +/- 3 to 158 +/- 7 mmHg, T0 to T10, P < 0.001, one way ANOVA). There was no significant difference in SBP between BH4 + ACTH treated and vehicle + ACTH treated rats. Thus, daily injection of BH4 (10 mg/kg i.p.) failed to prevent the development of ACTH-induced hypertension in rat.
Collapse
Affiliation(s)
- Y Zhang
- High Blood Pressure Research Unit, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | | | | | | | | |
Collapse
|
18
|
Leitner KL, Meyer M, Leimbacher W, Peterbauer A, Hofer S, Heufler C, Müller A, Heller R, Werner ER, Thöny B, Werner-Felmayer G. Low tetrahydrobiopterin biosynthetic capacity of human monocytes is caused by exon skipping in 6-pyruvoyl tetrahydropterin synthase. Biochem J 2003; 373:681-8. [PMID: 12708971 PMCID: PMC1223526 DOI: 10.1042/bj20030269] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2003] [Revised: 03/25/2003] [Accepted: 04/23/2003] [Indexed: 12/21/2022]
Abstract
Biosynthesis of (6 R )-5,6,7,8-tetrahydro-L-biopterin (H(4)-biopterin), an essential cofactor for aromatic amino acid hydroxylases and NO synthases, is effectively induced by cytokines in most of the cell types. However, human monocytes/macrophages form only a little H(4)-biopterin, but release neopterin/7,8-dihydroneopterin instead. Whereas 6-pyruvoyl tetrahydropterin synthase (PTPS) activity, the second enzyme of H(4)-biopterin biosynthesis, is hardly detectable in these cells, PTPS mRNA levels were comparable with those of cell types containing intact PTPS activity. By screening a THP-1 cDNA library, we identified clones encoding the entire open reading frame (642 bp) as well as clones lacking the 23 bp exon 3, which results in a premature stop codon. Quantification of the two mRNA species in different cell types (blood-derived cells, fibroblasts and endothelial cells) and cell lines showed that the amount of exon-3-containing mRNA is correlated closely to PTPS activity. The ratio of exon-3-containing to exon-3-lacking PTPS mRNA is not affected by differential mRNA stability or nonsense-mediated mRNA decay. THP-1 cells transduced with wild-type PTPS cDNA produced H(4)-biopterin levels and expressed PTPS activities and protein amounts comparable with those of fibroblasts. We therefore conclude that exon 3 skipping in transcription rather than post-transcriptional mechanisms is a major cause of the low PTPS protein expression observed in human macrophages and related cell types.
Collapse
Affiliation(s)
- Karin L Leitner
- Institute of Medical Chemistry and Biochemistry, University of Innsbruck, Fritz-Pregl-Strasse 3, A-6020 Innsbruck, Austria
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Elzaouk L, Leimbacher W, Turri M, Ledermann B, Burki K, Blau N, Thony B. Dwarfism and low insulin-like growth factor-1 due to dopamine depletion in Pts-/- mice rescued by feeding neurotransmitter precursors and H4-biopterin. J Biol Chem 2003; 278:28303-11. [PMID: 12734191 DOI: 10.1074/jbc.m303986200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The tetrahydrobiopterin (BH4) cofactor is essential for the biosynthesis of catecholamines and serotonin and for nitric-oxide synthase (NOS). Alterations in BH4 metabolism are observed in various neurological and psychiatric diseases, and mutations in one of the human metabolic genes causes hyperphenylalaninemia and/or monoamine neurotransmitter deficiency. We report on a knockout mouse for the Pts gene, which codes for a BH4-biosynthetic enzyme. Homozygous Pts-/- mice developed with normal morphology but died after birth. Upon daily oral administration of BH4 and neurotransmitter precursors the Pts-/- mice eventually survived. However, at sexual maturity (6 weeks) the mice had only one-third of the normal body weight and were sexually immature. Biochemical analysis revealed no hyperphenylalaninemia, normal brain NOS activity, and almost normal serotonin levels, but brain dopamine was 3% of normal. Low dopamine leads to impaired food consumption as reflected by the severe growth deficiency and a 7-fold reduced serum insulin-like growth factor-1 (IGF-1). This is the first link shown between 6-pyruvoyltetrahydropterin synthase- or BH4-biosynthetic activity and IGF-1.
Collapse
Affiliation(s)
- Lina Elzaouk
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, Division of Animal Facility, University of Zürich, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
20
|
Blau N, Thöny B. Possible impact of tetrahydrobiopterin and sepiapterin on endothelial dysfunction. Arterioscler Thromb Vasc Biol 2003; 23:913-4; author reply 914-5. [PMID: 12740227 DOI: 10.1161/01.atv.0000068647.92130.0d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
21
|
Madsen JT, Jansen P, Hesslinger C, Meyer M, Zimmer J, Gramsbergen JB. Tetrahydrobiopterin precursor sepiapterin provides protection against neurotoxicity of 1-methyl-4-phenylpyridinium in nigral slice cultures. J Neurochem 2003; 85:214-23. [PMID: 12641743 DOI: 10.1046/j.1471-4159.2003.01666.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Complex-I inhibition and oxidative processes have been implicated in the loss of nigral dopamine neurones in Parkinson's disease and the toxicity of MPTP and its metabolite MPP+. Tetrahydrobiopterin, an essential cofactor for tyrosine hydroxylase, may act as an antioxidant in dopaminergic neurones and protects against the toxic consequences of glutathione depletion. Here we studied the effects of manipulating tetrahydrobiopterin levels on MPP+ toxicity in organotypic, rat ventral mesencephalic slice cultures. In cultures exposed to 30 micro m MPP+ for 2 days, followed by 8 days 'recovery' in control medium, we measured dopamine and its metabolites in the tissue and culture medium by HPLC, lactate dehydrogenase release to the culture medium, cellular uptake of propidium iodide and counted the tyrosine hydroxylase-immunoreactive neurones. Inhibition of tetrahydrobiopterin synthesis by 2,4-diamino-6-hydroxypyrimidine had no significant synergistic effect on MPP+ toxicity. In contrast, the tetrahydrobiopterin precursor l-sepiapterin attenuated the MPP+-induced dopamine depletion and loss of tyrosine hydroxylase-positive cells in a dose-dependent manner with 40 micro m l-sepiapterin providing maximal protection. Accordingly, increasing intracellular tetrahydrobiopterin levels may protect against oxidative stress by complex-I inhibition.
Collapse
Affiliation(s)
- Jakob Torp Madsen
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Odense, Denmark
| | | | | | | | | | | |
Collapse
|
22
|
Rabbani GH, Saha SK, Akhtar M, Marni F, Mitra AK, Ahmed S, Alauddin M, Bhattacharjee M, Sultana S, Chowdhury AKA. Antioxidants in detoxification of arsenic-induced oxidative injury in rabbits: preliminary results. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2003; 38:273-287. [PMID: 12635832 DOI: 10.1081/ese-120016894] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To assess the oxidative injuries caused by arsenic toxicity in rabbits and evaluate the detoxifying effects of exogenous antioxidants, we administered arsenic trioxide (3-5 mg/kg/day) in rabbits through a feeding tube for seven days. These rabbits were then treated with a recipe of vitamins, zinc, selenium (VZS) or a plant polyphenol or a placebo for the next seven days. Blood samples were collected from ear vein for spectrophotometric assay of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), and nitrite/nitrate (NOx; index of nitric oxide formation) before arsenic administration, seven days after arsenic administration, and seven days after antioxidant treatment. The total arsenic concentrations in hair and spot urine samples of rabbits before arsenic administration were 0.6 +/- 0.21 microg/g and 34.0 +/- 5.9 microg/L, respectively. Administration of arsenic trioxide significantly increased arsenic concentrations in hair and in urine to 2.8 +/- 0.40 microg/g (p<0.001) and 7372 +/- 1392.0 microg/L (p<0.001), respectively. Arsenic administration to rabbits significantly reduced GSH concentration (post-arsenic, 17.5 +/- 0.81 mg/dL vs. pre-arsenic, 32.0 +/- 0.76 mg/dL, p<0.001), increased TBARS concentration (post-arsenic, 8 +/- 1.1 microM vs. pre-arsenic, 5 +/- 0.7 microM, p<0.05), and NOx concentration (post-arsenic, 465 +/- 38.5 microM vs. pre-arsenic, 320 +/- 24.7 microM, p<0.001) as compared to the pre-arsenic levels. There was a negative correlation between TBARS and GSH concentrations (r=-0.464, p<0.01) and between NOx and GSH concentrations (r=-0.381, p<0.05) of intoxicated rabbits. The recovery of the depleted GSH was significantly greater in the polyphenols (77.0 +/- 12.0%) or VZS (67.0 +/- 17.0%) treatment groups compared with the placebo group (36.0 +/- 7.0%). The decrease in NOx level of arsenic-treated rabbits was significantly greater in polyphenols treatment group than the placebo group (60.0 +/- 9.0% vs. 17.0 +/- 6.0%, p<0.001). These results indicate that arsenic induces toxicity in rabbits associated with an increase in lipid peroxidation. Arsenic toxicity increases nitric oxide production in the body. Exogenous antioxidants such as polyphenols and recipe of vitamins, zinc, and selenium are useful for arsenic detoxification.
Collapse
Affiliation(s)
- Golam Hassan Rabbani
- Physiology Laboratory, Clinical Sciences Division, ICDDR,B: Centre for Health and Population Research, Dhaka, Bangladesh.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Zorzi G, Redweik U, Trippe H, Penzien JM, Thöny B, Blau N. Detection of sepiapterin in CSF of patients with sepiapterin reductase deficiency. Mol Genet Metab 2002; 75:174-7. [PMID: 11855937 DOI: 10.1006/mgme.2001.3273] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sepiapterin reductase (SR) deficiency was recently described in patients with a severe biogenic amine deficiency presenting without hyperphenylalaninemia and it was suggested that the tetrahydrobiopterin (BH(4)) pathway may be different in different cells and tissues. We now developed a HPLC method for the measurement of yellow fluorescing sepiapterin for the rapid diagnosis of SR deficiency. Sepiapterin was elevated in CSF from two patients with SR deficiency (5.6 and 11.4 nmol/L) when compared with healthy controls (<0.5 nmol/L). Our data further support the hypothesis that sepiapterin is an intermediate in the salvage pathway of BH(4) and that it accumulates in the brain of patients with SR deficiency.
Collapse
Affiliation(s)
- Giovanna Zorzi
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital, Steinwiesstrasse 75, 8032 Zurich, Switzerland
| | | | | | | | | | | |
Collapse
|