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Suitability and Allocation of Protein-Containing Foods According to Protein Tolerance in PKU: A 2022 UK National Consensus. Nutrients 2022; 14:nu14234987. [PMID: 36501017 PMCID: PMC9736047 DOI: 10.3390/nu14234987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
Introduction: There is little practical guidance about suitable food choices for higher natural protein tolerances in patients with phenylketonuria (PKU). This is particularly important to consider with the introduction of adjunct pharmaceutical treatments that may improve protein tolerance. Aim: To develop a set of guidelines for the introduction of higher protein foods into the diets of patients with PKU who tolerate >10 g/day of protein. Methods: In January 2022, a 26-item food group questionnaire, listing a range of foods containing protein from 5 to >20 g/100 g, was sent to all British Inherited Metabolic Disease Group (BIMDG) dietitians (n = 80; 26 Inherited Metabolic Disease [IMD] centres). They were asked to consider within their IMD dietetic team when they would recommend introducing each of the 26 protein-containing food groups into a patient’s diet who tolerated >10 g to 60 g/day of protein. The patient protein tolerance for each food group that received the majority vote from IMD dietetic teams was chosen as its tolerance threshold for introduction. A virtual meeting was held using Delphi methodology in March 2022 to discuss and agree final consensus. Results: Responses were received from dietitians from 22/26 IMD centres (85%) (11 paediatric, 11 adult). For patients tolerating protein ≥15 g/day, the following foods were agreed for inclusion: gluten-free pastas, gluten-free flours, regular bread, cheese spreads, soft cheese, and lentils in brine; for protein tolerance ≥20 g/day: nuts, hard cheeses, regular flours, meat/fish, and plant-based alternative products (containing 5−10 g/100 g protein), regular pasta, seeds, eggs, dried legumes, and yeast extract spreads were added; for protein tolerance ≥30 g/day: meat/fish and plant-based alternative products (containing >10−20 g/100 g protein) were added; and for protein tolerance ≥40 g/day: meat/fish and plant-based alternatives (containing >20 g/100 g protein) were added. Conclusion: This UK consensus by IMD dietitians from 22 UK centres describes for the first time the suitability and allocation of higher protein foods according to individual patient protein tolerance. It provides valuable guidance for health professionals to enable them to standardize practice and give rational advice to patients.
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Ilgaz F, Marsaux C, Pinto A, Singh R, Rohde C, Karabulut E, Gökmen-Özel H, Kuhn M, MacDonald A. Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis. Nutrients 2021; 13:1040. [PMID: 33807079 PMCID: PMC8004763 DOI: 10.3390/nu13031040] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/12/2021] [Accepted: 03/19/2021] [Indexed: 11/16/2022] Open
Abstract
The traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietary protocols guiding the adjustments of protein equivalent intake from protein substitute with BH4 treatment are lacking. We systematically reviewed protein substitute usage with long-term BH4 therapy. Electronic databases were searched for articles published between January 2000 and March 2020. Eighteen studies (306 PKU patients) were eligible. Meta-analyses demonstrated a significant increase in Phe and natural protein intakes and a significant decrease in protein equivalent intake from protein substitute with cofactor therapy. Protein substitute could be discontinued in 51% of responsive patients, but was still required in 49%, despite improvement in Phe tolerance. Normal growth was maintained, but micronutrient deficiency was observed with BH4 treatment. A systematic protocol to increase natural protein intake while reducing protein substitute dose should be followed to ensure protein and micronutrient requirements are met and sustained. We propose recommendations to guide healthcare professionals when adjusting dietary prescriptions of PKU patients on BH4. Studies investigating new therapeutic options in PKU should systematically collect data on protein substitute and natural protein intakes, as well as other nutritional factors.
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Affiliation(s)
- Fatma Ilgaz
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey; (F.I.); (H.G.-Ö.)
| | - Cyril Marsaux
- Danone Nutricia Research, 3584CT Utrecht, The Netherlands;
| | - Alex Pinto
- Department of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.P.); (A.M.)
| | - Rani Singh
- Metabolic Genetics Nutrition Program, Department of Human Genetics, Emory University, Atlanta, GA 30322, USA;
| | - Carmen Rohde
- Department of Paediatrics of the University Clinics Leipzig, University of Leipzig, 04103 Leipzig, Germany;
| | - Erdem Karabulut
- Department of Biostatistics, Faculty of Medicine, Hacettepe University, 06100 Ankara, Turkey;
| | - Hülya Gökmen-Özel
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey; (F.I.); (H.G.-Ö.)
| | - Mirjam Kuhn
- Danone Nutricia Research, 3584CT Utrecht, The Netherlands;
| | - Anita MacDonald
- Department of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.P.); (A.M.)
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Kraft VN, Bezjian CT, Pfeiffer S, Ringelstetter L, Müller C, Zandkarimi F, Merl-Pham J, Bao X, Anastasov N, Kössl J, Brandner S, Daniels JD, Schmitt-Kopplin P, Hauck SM, Stockwell BR, Hadian K, Schick JA. GTP Cyclohydrolase 1/Tetrahydrobiopterin Counteract Ferroptosis through Lipid Remodeling. ACS CENTRAL SCIENCE 2020; 6:41-53. [PMID: 31989025 PMCID: PMC6978838 DOI: 10.1021/acscentsci.9b01063] [Citation(s) in RCA: 569] [Impact Index Per Article: 142.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Indexed: 05/03/2023]
Abstract
Ferroptosis is an iron-dependent form of regulated cell death linking iron, lipid, and glutathione levels to degenerative processes and tumor suppression. By performing a genome-wide activation screen, we identified a cohort of genes antagonizing ferroptotic cell death, including GTP cyclohydrolase-1 (GCH1) and its metabolic derivatives tetrahydrobiopterin/dihydrobiopterin (BH4/BH2). Synthesis of BH4/BH2 by GCH1-expressing cells caused lipid remodeling, suppressing ferroptosis by selectively preventing depletion of phospholipids with two polyunsaturated fatty acyl tails. GCH1 expression level in cancer cell lines stratified susceptibility to ferroptosis, in accordance with its expression in human tumor samples. The GCH1-BH4-phospholipid axis acts as a master regulator of ferroptosis resistance, controlling endogenous production of the antioxidant BH4, abundance of CoQ10, and peroxidation of unusual phospholipids with two polyunsaturated fatty acyl tails. This demonstrates a unique mechanism of ferroptosis protection that is independent of the GPX4/glutathione system.
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Affiliation(s)
- Vanessa
A. N. Kraft
- Institute
of Molecular Toxicology and Pharmacology, Genetics and Cellular Engineering
Group, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Carla T. Bezjian
- Department
of Chemistry, Columbia University, 550 West 120th Street, MC4846, New York, New York 10027, United States
| | - Susanne Pfeiffer
- Institute
of Molecular Toxicology and Pharmacology, Genetics and Cellular Engineering
Group, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Larissa Ringelstetter
- Institute
of Molecular Toxicology and Pharmacology, Assay Development and Screening
Platform, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Constanze Müller
- Research
Unit Analytical BioGeoChemistry, HelmholtzZentrum
Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Fereshteh Zandkarimi
- Department
of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Juliane Merl-Pham
- Research
Unit Protein Science, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Xuanwen Bao
- Institute
of Radiation Biology, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Natasa Anastasov
- Institute
of Radiation Biology, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Johanna Kössl
- Institute
of Molecular Toxicology and Pharmacology, Genetics and Cellular Engineering
Group, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Stefanie Brandner
- Institute
of Molecular Toxicology and Pharmacology, Assay Development and Screening
Platform, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Jacob D. Daniels
- Department
of Pharmacology, Columbia University, New York, New York 10027, United States
| | - Philippe Schmitt-Kopplin
- Research
Unit Analytical BioGeoChemistry, HelmholtzZentrum
Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Stefanie M. Hauck
- Research
Unit Protein Science, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Brent R. Stockwell
- Department
of Chemistry, Columbia University, 550 West 120th Street, MC4846, New York, New York 10027, United States
- Department
of Biological Sciences, Columbia University, New York, New York 10027, United States
- E-mail:
| | - Kamyar Hadian
- Institute
of Molecular Toxicology and Pharmacology, Assay Development and Screening
Platform, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
- E-mail:
| | - Joel A. Schick
- Institute
of Molecular Toxicology and Pharmacology, Genetics and Cellular Engineering
Group, HelmholtzZentrum Muenchen, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
- E-mail:
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Montoya Parra GA, Singh RH, Cetinyurek-Yavuz A, Kuhn M, MacDonald A. Status of nutrients important in brain function in phenylketonuria: a systematic review and meta-analysis. Orphanet J Rare Dis 2018; 13:101. [PMID: 29941009 PMCID: PMC6020171 DOI: 10.1186/s13023-018-0839-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023] Open
Abstract
Background Despite early and ongoing dietary management with a phe-restricted diet, suboptimal neuropsychological function has been observed in PKU. The restrictive nature of the PKU diet may expose patients to sub-optimal nutritional intake and deficiencies which may impact normal brain function. A systematic review of the published literature was carried out, where possible with meta-analysis, to compare the status of nutrients (Nutrients: DHA, EPA phospholipids, selenium, vitamins B6, B12, E, C, A, D, folic acid, choline, uridine, calcium, magnesium, zinc, iron, iodine and cholesterol) known to be important for brain development and functioning between individuals with PKU and healthy controls. Results Of 1534 publications identified, 65 studies met the entry criteria. Significantly lower levels of DHA, EPA and cholesterol were found for PKU patients compared to healthy controls. No significant differences in zinc, vitamins B12, E and D, calcium, iron and magnesium were found between PKU patients and controls. Because of considerable heterogeneity, the meta-analyses findings for folate and selenium were not reported. Due to an insufficient number of publications (< 4) no meta-analysis was undertaken for vitamins A, C and B6, choline, uridine, iodine and phospholipids. Conclusions The current data show that PKU patients have lower availability of DHA, EPA and cholesterol. Compliance with the phe-restricted diet including the micronutrient fortified protein substitute (PS) is essential to ensure adequate micronutrient status. Given the complexity of the diet, patients’ micronutrient and fatty acid status should be continuously monitored, with a particular focus on patients who are non-compliant or poorly compliant with their PS. Given their key role in brain function, assessment of the status of nutrients where limited data was found (e.g. choline, iodine) should be undertaken. Standardised reporting of studies in PKU would strengthen the output of meta-analysis and so better inform best practice for this rare condition. Electronic supplementary material The online version of this article (10.1186/s13023-018-0839-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gina A Montoya Parra
- Danone Nutricia Research, Nutricia Advanced Medical Nutrition, Utrecht, The Netherlands.
| | - Rani H Singh
- Metabolic Genetics and Nutrition Program, Emory University, Atlanta, GA, USA
| | | | - Mirjam Kuhn
- Danone Nutricia Research, Nutricia Advanced Medical Nutrition, Utrecht, The Netherlands
| | - Anita MacDonald
- Department of Metabolic Diseases, Birmingham Children's Hospital, Birmingham, UK
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Gramer G, Haege G, Langhans CD, Schuhmann V, Burgard P, Hoffmann GF. Long-chain polyunsaturated fatty acid status in children, adolescents and adults with phenylketonuria. Prostaglandins Leukot Essent Fatty Acids 2016; 109:52-7. [PMID: 27269713 DOI: 10.1016/j.plefa.2016.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/18/2016] [Accepted: 04/18/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Patients with phenylketonuria have been reported to be deficient in long-chain polyunsaturated fatty acids (LCPUFAs). It has been postulated that good compliance with the dietary regimen negatively influences LCPUFA status. METHODS In 36 patients with phenylketonuria and 18 age-matched healthy control subjects LCPUFA-levels in plasma phospholipids and cholesteryl esters, erythrocyte phosphatidylcholine and phosphatidylethanolamine were evaluated. RESULTS Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels did not differ significantly between patients and control subjects in plasma and erythrocyte fractions. There was a significant negative correlation between SDS (standard deviation) scores of DHA-levels in erythrocyte parameters from the respective age-matched control group and patients' concurrent and long-term phenylalanine levels for erythrocyte phosphatidylethanolamine and erythrocyte phosphatidylcholine. Patients with lower (higher) phenylalanine levels had positive (negative) DHA-SDS. CONCLUSION In contrast to previous reports we did not find lower LCPUFA-levels in patients with phenylketonuria compared to age-matched healthy control subjects. Good dietary control was associated with better LCPUFA status.
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Affiliation(s)
- Gwendolyn Gramer
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Gisela Haege
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Claus-Dieter Langhans
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Vera Schuhmann
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Peter Burgard
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
| | - Georg F Hoffmann
- Centre for Paediatric and Adolescent Medicine, Division for Neuropaediatrics and Metabolic Medicine, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany.
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6
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Lower n-3 long-chain polyunsaturated fatty acid values in patients with phenylketonuria: a systematic review and meta-analysis. Nutr Res 2013; 33:513-20. [DOI: 10.1016/j.nutres.2013.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 11/18/2022]
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Abstract
Phenylalanine hydroxylase deficiency is an autosomal recessive disorder that results in intolerance to the dietary intake of the essential amino acid phenylalanine. It occurs in approximately 1:15,000 individuals. Deficiency of this enzyme produces a spectrum of disorders including classic phenylketonuria, mild phenylketonuria, and mild hyperphenylalaninemia. Classic phenylketonuria is caused by a complete or near-complete deficiency of phenylalanine hydroxylase activity and without dietary restriction of phenylalanine most children will develop profound and irreversible intellectual disability. Mild phenylketonuria and mild hyperphenylalaninemia are associated with lower risk of impaired cognitive development in the absence of treatment. Phenylalanine hydroxylase deficiency can be diagnosed by newborn screening based on detection of the presence of hyperphenylalaninemia using the Guthrie microbial inhibition assay or other assays on a blood spot obtained from a heel prick. Since the introduction of newborn screening, the major neurologic consequences of hyperphenylalaninemia have been largely eradicated. Affected individuals can lead normal lives. However, recent data suggest that homeostasis is not fully restored with current therapy. Treated individuals have a higher incidence of neuropsychological problems. The mainstay of treatment for hyperphenylalaninemia involves a low-protein diet and use of a phenylalanine-free medical formula. This treatment must commence as soon as possible after birth and should continue for life. Regular monitoring of plasma phenylalanine and tyrosine concentrations is necessary. Targets of plasma phenylalanine of 120-360 μmol/L (2-6 mg/dL) in the first decade of life are essential for optimal outcome. Phenylalanine targets in adolescence and adulthood are less clear. A significant proportion of patients with phenylketonuria may benefit from adjuvant therapy with 6R-tetrahydrobiopterin stereoisomer. Special consideration must be given to adult women with hyperphenylalaninemia because of the teratogenic effects of phenylalanine. Women with phenylalanine hydroxylase deficiency considering pregnancy should follow special guidelines and assure adequate energy intake with the proper proportion of protein, fat, and carbohydrates to minimize risks to the developing fetus. Molecular genetic testing of the phenylalanine hydroxylase gene is available for genetic counseling purposes to determine carrier status of at-risk relatives and for prenatal testing.
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Wang H, Yang B, Hao G, Feng Y, Chen H, Feng L, Zhao J, Zhang H, Chen YQ, Wang L, Chen W. Biochemical characterization of the tetrahydrobiopterin synthesis pathway in the oleaginous fungus Mortierella alpina. MICROBIOLOGY (READING, ENGLAND) 2011; 157:3059-3070. [PMID: 21852350 PMCID: PMC4811656 DOI: 10.1099/mic.0.051847-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/10/2011] [Accepted: 08/17/2011] [Indexed: 11/18/2022]
Abstract
We characterized the de novo biosynthetic pathway of tetrahydrobiopterin (BH₄) in the lipid-producing fungus Mortierella alpina. The BH₄ cofactor is essential for various cell processes, and is probably present in every cell or tissue of higher organisms. Genes encoding two copies of GTP cyclohydrolase I (GTPCH-1 and GTPCH-2) for the conversion of GTP to dihydroneopterin triphosphate (H₂-NTP), 6-pyruvoyltetrahydropterin synthase (PTPS) for the conversion of H₂-NTP to 6-pyruvoyltetrahydropterin (PPH₄), and sepiapterin reductase (SR) for the conversion of PPH₄ to BH₄, were expressed heterologously in Escherichia coli. The recombinant enzymes were produced as His-tagged fusion proteins and were purified to homogeneity to investigate their enzymic activities. Enzyme products were analysed by HPLC and electrospray ionization-MS. Kinetic parameters and other properties of GTPCH, PTPS and SR were investigated. Physiological roles of BH₄ in M. alpina are discussed, and comparative analyses between GTPCH, PTPS and SR proteins and other homologous proteins were performed. The presence of two functional GTPCH enzymes has, as far as we are aware, not been reported previously, reflecting the unique ability of this fungus to synthesize both BH₄ and folate, using the GTPCH product as a common substrate. To our knowledge, this study is the first to report the comprehensive characterization of a BH₄ biosynthesis pathway in a fungus.
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Affiliation(s)
- Hongchao Wang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Bo Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Guangfei Hao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Yun Feng
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Lu Feng
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Yong Q. Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
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9
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Bélanger-Quintana A, Burlina A, Harding CO, Muntau AC. Up to date knowledge on different treatment strategies for phenylketonuria. Mol Genet Metab 2011; 104 Suppl:S19-25. [PMID: 21967857 PMCID: PMC4437510 DOI: 10.1016/j.ymgme.2011.08.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 07/23/2011] [Accepted: 08/05/2011] [Indexed: 11/18/2022]
Abstract
Dietary management for phenylketonuria was established over half a century ago, and has rendered an immense success in the prevention of the severe mental retardation associated with the accumulation of phenylalanine. However, the strict low-phenylalanine diet has several shortcomings, not the least of which is the burden it imposes on the patients and their families consequently frequent dietary non-compliance. Imperfect neurological outcome of patients in comparison to non-PKU individuals and nutritional deficiencies associated to the PKU diet are other important reasons to seek alternative therapies. In the last decade there has been an impressive effort in the investigation of other ways to treat PKU that might improve the outcome and quality of life of these patients. These studies have lead to the commercialization of sapropterin dihydrochloride, but there are still many questions regarding which patients to challenge with sapropterin what is the best challenge protocol and what could be the implications of this treatment in the long-term. Current human trials of PEGylated phenylalanine ammonia lyase are underway, which might render an alternative to diet for those patients non-responsive to sapropterin dihydrochloride. Preclinical investigation of gene and cell therapies for PKU is ongoing. In this manuscript, we will review the current knowledge on novel pharmacologic approaches to the treatment of phenylketonuria.
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Affiliation(s)
- Amaya Bélanger-Quintana
- Division of Metabolic Diseases, Pediatrics Department, Ramon y Cajal Hospital, Madrid, Spain.
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10
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Demirkol M, Giżewska M, Giovannini M, Walter J. Follow up of phenylketonuria patients. Mol Genet Metab 2011; 104 Suppl:S31-9. [PMID: 22018725 DOI: 10.1016/j.ymgme.2011.08.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/31/2011] [Accepted: 08/07/2011] [Indexed: 11/26/2022]
Abstract
In recent years our understanding of the follow up policies for PKU has increased substantially. In particular, we now understand the importance of maintaining control of blood phenylalanine (phe) concentrations life-long to achieve the best long-term neuropsychological outcomes. The concordance with the follow up strategy remains a key challenge for the future, especially with respect to adolescents and young adults. The recent therapies could ease the burden of the dietary phe restriction for PKU patients and their families. The time may be right for revisiting the guidelines for follow up of PKU in order to address a number of important issues related to PKU management: promotion of breastfeeding to complementary feeding up to 2 years of age for prevention of early growth retardation and later overweight development, treatment advancements for metabolic control, blood phe and tyr variability, routine screening measures for nutritional biomarkers, neurocognitive and psychological assessments, bone pathology, understanding the challenges of compliance and transitioning into adulthood as an individual with PKU and addressing unmet needs in this population.
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Affiliation(s)
- M Demirkol
- Div Nutrition and Metabolism, Children's Hospital, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey.
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11
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Lage S, Bueno M, Andrade F, Prieto JA, Delgado C, Legarda M, Sanjurjo P, Aldámiz-Echevarría LJ. Fatty acid profile in patients with phenylketonuria and its relationship with bone mineral density. J Inherit Metab Dis 2010; 33 Suppl 3:S363-71. [PMID: 20830525 DOI: 10.1007/s10545-010-9189-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 07/21/2010] [Accepted: 08/06/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Patients with phenylketonuria (PKU) undergo a restrictive vegan-like diet, with almost total absence of n-3 fatty acids, which have been proposed as potential contributors to bone formation in the healthy population. The PKU diet might lead these patients to bone mass loss and, consequently, to the development of osteopenia/osteoporosis. Therefore, we proposed to analyze their plasma fatty acid profile status and its relationship with bone health. METHODS We recruited 47 PKU patients for this cross-sectional study and divided the cohort into three age groups (6-10 years, 11-18 years, 19-42 years). We measured their plasma fatty acid profile and bone mineral density (BMD) (both at the femoral neck and the lumbar spine). Seventy-seven healthy controls also participated as reference values of plasma fatty acids. RESULTS Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and total n-3 fatty acids were significantly diminished in PKU patients compared with healthy controls. DHA, EPA, and total n-3 fatty acids were also positively associated with bone mineral density (r = 0.83, p = 0.010; r = 0.57, p = 0.006; r = 0.73, p = 0.040, respectively). There was no association between phenylalanine (Phe), Index of Dietary Control (IDC), calcium, 25-hydroxivitamin D concentrations, daily calcium intake, and BMD. CONCLUSION Our results suggest a possible influence of essential fatty acids over BMD in PKU patients. The lack of essential n-3 fatty acids intake in the PKU diet might affect bone mineralization. Further clinical trials are needed to confirm the effect of the n-3 essential fatty acids on bone accrual in a cohort of PKU patients.
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Affiliation(s)
- Sergio Lage
- Division of Metabolism, Department of Paediatrics, Cruces Hospital, Plaza de Cruces, 48903 Barakaldo, Vizcaya, Spain.
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