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Bernardini G, Braconi D, Zatkova A, Sireau N, Kujawa MJ, Introne WJ, Spiga O, Geminiani M, Gallagher JA, Ranganath LR, Santucci A. Alkaptonuria. Nat Rev Dis Primers 2024; 10:16. [PMID: 38453957 DOI: 10.1038/s41572-024-00498-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
Alkaptonuria is a rare inborn error of metabolism caused by the deficiency of homogentisate 1,2-dioxygenase activity. The consequent homogentisic acid (HGA) accumulation in body fluids and tissues leads to a multisystemic and highly debilitating disease whose main features are dark urine, ochronosis (HGA-derived pigment in collagen-rich connective tissues), and a painful and severe form of osteoarthropathy. Other clinical manifestations are extremely variable and include kidney and prostate stones, aortic stenosis, bone fractures, and tendon, ligament and/or muscle ruptures. As an autosomal recessive disorder, alkaptonuria affects men and women equally. Debilitating symptoms appear around the third decade of life, but a proper and timely diagnosis is often delayed due to their non-specific nature and a lack of knowledge among physicians. In later stages, patients' quality of life might be seriously compromised and further complicated by comorbidities. Thus, appropriate management of alkaptonuria requires a multidisciplinary approach, and periodic clinical evaluation is advised to monitor disease progression, complications and/or comorbidities, and to enable prompt intervention. Treatment options are patient-tailored and include a combination of medications, physical therapy and surgery. Current basic and clinical research focuses on improving patient management and developing innovative therapies and implementing precision medicine strategies.
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Affiliation(s)
- Giulia Bernardini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
| | - Daniela Braconi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Andrea Zatkova
- Institute of Clinical and Translational Research, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
- Geneton Ltd, Bratislava, Slovakia
| | | | - Mariusz J Kujawa
- 2nd Department of Radiology, Medical University of Gdansk, Gdansk, Poland
| | - Wendy J Introne
- Human Biochemical Genetics Section, Medical Genetics Branch, Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ottavia Spiga
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Michela Geminiani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - James A Gallagher
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences University of Liverpool, Liverpool, UK
| | - Lakshminarayan R Ranganath
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences University of Liverpool, Liverpool, UK
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital, Liverpool, UK
| | - Annalisa Santucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
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2
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Genovese F, Frederiksen P, Bay-Jensen AC, Karsdal MA, Milan AM, Olsson B, Rudebeck M, Gallagher JA, Ranganath LR. Nitisinone Treatment Affects Biomarkers of Bone and Cartilage Remodelling in Alkaptonuria Patients. Int J Mol Sci 2023; 24:10996. [PMID: 37446173 DOI: 10.3390/ijms241310996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Nitisinone has been approved for treatment of alkaptonuria (AKU). Non-invasive biomarkers of joint tissue remodelling could aid in understanding the molecular changes in AKU pathogenesis and how these can be affected by treatment. Serological and urinary biomarkers of type I collagen and II collagen in AKU were investigated in patients enrolled in the randomized SONIA 2 (NCT01916382) clinical study at baseline and yearly until the end of the study (Year 4). The trajectories of the biomarkers over time were observed. After treatment with nitisinone, the biomarkers of type I collagen remodelling increased at Year 1 (19% and 40% increase in CTX-I and PRO-C1, respectively), which was potentially reflected in the higher degree of mobility seen following treatment. The biomarkers of type II collagen remodelling decreased over time in the nitisinone group: C2M showed a 9.7% decline at Year 1, and levels then remained stable over the following visits; CTX-II showed a 26% decline at Year 3 and 4 in the nitisinone-treated patients. Nitisinone treatment induced changes in biomarkers of bone and cartilage remodelling. These biomarkers can aid patient management and deepen our knowledge of the molecular mechanisms of this rare disease.
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Affiliation(s)
| | | | | | | | - Anna M Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Liverpool University Hospitals NHS Foundation Trust, Liverpool L69 3BX, UK
| | | | | | - James A Gallagher
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3BX, UK
| | - Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Liverpool University Hospitals NHS Foundation Trust, Liverpool L69 3BX, UK
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3
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Davison AS, Norman BP. Alkaptonuria – Past, present and future. Adv Clin Chem 2023. [DOI: 10.1016/bs.acc.2023.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Shepherd HR, Robinson MA, Ranganath LR, Barton GJ. Identifying joint-specific gait mechanisms causing impaired gait in alkaptonuria patients. Gait Posture 2022; 91:312-317. [PMID: 34800924 DOI: 10.1016/j.gaitpost.2021.10.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/28/2021] [Accepted: 10/18/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Alkaptonuria is a rare genetic disease that leads to structural joint damage and impaired movement function. Previous research indicates that alkaptonuria affects gait, however the detailed mechanisms are unknown. RESEARCH QUESTION What are the joint-specific gait mechanisms which contribute to impaired gait in alkaptonuria patients? METHODS The gait of 36 alkaptonuria patients were compared to those of 21 unimpaired controls. The AKU patients were split into three age groups (young 16-29 years, n = 9, middle 30-49 years, n = 16 and old 50 + years, n = 11), and the kinematic and kinetic gait profiles were compared to speed-matched controls using a spm1d two-sample t-test. RESULTS The young AKU group showed significant differences in the sagittal plane of the knee joint compared to speed-matched controls. The middle group showed deviations in the knee and hip joints. The old group showed significant differences in multiple joints and planes and exhibited gait mechanisms which may be compensation strategies. SIGNIFICANCE This study is the first to identify and describe joint-specific mechanisms during gait in alkaptonuria patients. Gait deviations were evident even in young AKU patients, including a 16-year-old, much earlier than previously thought. The knee joint is an important focus of future research and potential interventions as deviations were found across all three AKU age groups.
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Affiliation(s)
- H R Shepherd
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
| | - M A Robinson
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
| | - L R Ranganath
- National Alkaptonuria Centre, Liverpool University Hospitals NHS Foundation Trust, Liverpool L7 8XP, United Kingdom.
| | - G J Barton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
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5
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Shepherd RF, Kerns JG, Ranganath LR, Gallagher JA, Taylor AM. "Lessons from Rare Forms of Osteoarthritis". Calcif Tissue Int 2021; 109:291-302. [PMID: 34417863 PMCID: PMC8403118 DOI: 10.1007/s00223-021-00896-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 07/27/2021] [Indexed: 12/12/2022]
Abstract
Osteoarthritis (OA) is one of the most prevalent conditions in the world, particularly in the developed world with a significant increase in cases and their predicted impact as we move through the twenty-first century and this will be exacerbated by the covid pandemic. The degeneration of cartilage and bone as part of this condition is becoming better understood but there are still significant challenges in painting a complete picture to recognise all aspects of the condition and what treatment(s) are most appropriate in individual causes. OA encompasses many different types and this causes some of the challenges in fully understanding the condition. There have been examples through history where much has been learnt about common disease(s) from the study of rare or extreme phenotypes, particularly where Mendelian disorders are involved. The often early onset of symptoms combined with the rapid and aggressive pathogenesis of these diseases and their predictable outcomes give an often-under-explored resource. It is these "rarer forms of disease" that William Harvey referred to that offer novel insights into more common conditions through their more extreme presentations. In the case of OA, GWAS analyses demonstrate the multiple genes that are implicated in OA in the general population. In some of these rarer forms, single defective genes are responsible. The extreme phenotypes seen in conditions such as Camptodactyly Arthropathy-Coxa Vara-pericarditis Syndrome, Chondrodysplasias and Alkaptonuria all present potential opportunities for greater understanding of disease pathogenesis, novel therapeutic interventions and diagnostic imaging. This review examines some of the rarer presenting forms of OA and linked conditions, some of the novel discoveries made whilst studying them, and findings on imaging and treatment strategies.
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Affiliation(s)
- Rebecca F Shepherd
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, UK
| | - Jemma G Kerns
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, UK
| | - Lakshminarayan R Ranganath
- Departments of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital, Liverpool, L7 8XP, UK
| | - James A Gallagher
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8T, UK
| | - Adam M Taylor
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, UK.
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Gallagher JA, Dillon JP, Ranganath LR. Development of an Effective Therapy for Alkaptonuria - Lessons for Osteoarthritis. RHEUMATOLOGY AND IMMUNOLOGY RESEARCH 2021; 2:79-85. [PMID: 36465977 PMCID: PMC9524786 DOI: 10.2478/rir-2021-0011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/21/2021] [Indexed: 06/17/2023]
Abstract
Osteoarthritis (OA) is one of the major causes of disability and pain worldwide, yet despite a massive international research effort, no effective disease-modifying drugs have been identified to date. In this review, we put forward the proposition that greater focus on rarer forms of OA could lead to a better understanding of the pathogenesis of more common OA. We have investigated the severe osteoarthropathy of the ultra-rare disease alkaptonuria (AKU). In addition to the progress made in finding a treatment for AKU, our research has revealed important lessons for more common OA, including the identification of high-density mineralized protrusions (HDMPs), new pathoanatomical structures which may play an important role in joint destruction and pain in AKU and in OA. AKU is an inherited disorder of tyrosine metabolism, caused by genetic lack of the enzyme homogentisate 1,2 dioxygenase (HGD), which leads to failure to breakdown homogentisic acid (HGA). While most HGA is excreted over time, some of it is deposited as a pigment in connective tissues, a process described as ochronosis. Ochronotic pigment alters the mechanical properties of tissues, leading to inevitable joint destruction and frequently to cardiac valve disease. Until recently, there was no effective therapy for AKU, but preclinical studies demonstrated that upstream inhibition of tyrosine metabolism by nitisinone, a drug previously used in hereditary tyrosinaemia 1 (HT1), completely prevented ochronosis in AKU mice. This was followed by successful clinical trials which have resulted in nitisinone being approved for therapy of AKU by the European Medicines Agency, making AKU the only cause of OA for which there is an effective therapy to date. Study of other rare causes of OA should be a higher priority for researchers and funders to ensure further advances in understanding and eventual therapy of OA.
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Affiliation(s)
- James A. Gallagher
- Musculoskeletal Biology and Ageing, University of Liverpool, LiverpoolL7 8TX, UK
| | - Jane P. Dillon
- Musculoskeletal Biology and Ageing, University of Liverpool, LiverpoolL7 8TX, UK
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Hughes JH, Keenan CM, Sutherland H, Edwards HR, Wilson PJM, Ranganath LR, Jarvis JC, Bou-Gharios G, Gallagher JA. Anatomical Distribution of Ochronotic Pigment in Alkaptonuric Mice is Associated with Calcified Cartilage Chondrocytes at Osteochondral Interfaces. Calcif Tissue Int 2021; 108:207-218. [PMID: 33057760 PMCID: PMC7820185 DOI: 10.1007/s00223-020-00764-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/29/2020] [Indexed: 11/17/2022]
Abstract
Alkaptonuria (AKU) is characterised by increased circulating homogentisic acid and deposition of ochronotic pigment in collagen-rich connective tissues (ochronosis), stiffening the tissue. This process over many years leads to a painful and severe osteoarthropathy, particularly affecting the cartilage of the spine and large weight bearing joints. Evidence in human AKU tissue suggests that pigment binds to collagen. The exposed collagen hypothesis suggests that collagen is initially protected from ochronosis, and that ageing and mechanical loading causes loss of protective molecules, allowing pigment binding. Schmorl's staining has previously demonstrated knee joint ochronosis in AKU mice. This study documents more comprehensively the anatomical distribution of ochronosis in two AKU mouse models (BALB/c Hgd-/-, Hgd tm1a-/-), using Schmorl's staining. Progression of knee joint pigmentation with age in the two AKU mouse models was comparable. Within the knee, hip, shoulder, elbow and wrist joints, pigmentation was associated with chondrons of calcified cartilage. Pigmented chondrons were identified in calcified endplates of intervertebral discs and the calcified knee joint meniscus, suggesting that calcified tissues are more susceptible to pigmentation. There were significantly more pigmented chondrons in lumbar versus tail intervertebral disc endplates (p = 0.002) and clusters of pigmented chondrons were observed at the insertions of ligaments and tendons. These observations suggest that loading/strain may be associated with increased pigmentation but needs further experimental investigation. The calcified cartilage may be the first joint tissue to acquire matrix damage, most likely to collagen, through normal ageing and physiological loading, as it is the first to become susceptible to pigmentation.
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Affiliation(s)
- Juliette H Hughes
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK.
| | - Craig M Keenan
- School of Biological and Environmental Sciences, Faculty of Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Hazel Sutherland
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
- School of Sport and Exercise Science, Faculty of Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Henry R Edwards
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
| | - Peter J M Wilson
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
| | - Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital, Liverpool, L7 8XP, UK
| | - Jonathan C Jarvis
- School of Sport and Exercise Science, Faculty of Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - George Bou-Gharios
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK
| | - James A Gallagher
- Department of Musculoskeletal & Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, UK.
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Ranganath LR, Psarelli EE, Arnoux JB, Braconi D, Briggs M, Bröijersén A, Loftus N, Bygott H, Cox TF, Davison AS, Dillon JP, Fisher M, FitzGerald R, Genovese F, Glasova H, Hall AK, Hughes AT, Hughes JH, Imrich R, Jarvis JC, Khedr M, Laan D, Le Quan Sang KH, Luangrath E, Lukáčová O, Milan AM, Mistry A, Mlynáriková V, Norman BP, Olsson B, Rhodes NP, Rovenský J, Rudebeck M, Santucci A, Shweihdi E, Scott C, Sedláková J, Sireau N, Stančík R, Szamosi J, Taylor S, van Kan C, Vinjamuri S, Vrtíková E, Webb C, West E, Záňová E, Zatkova A, Gallagher JA. Efficacy and safety of once-daily nitisinone for patients with alkaptonuria (SONIA 2): an international, multicentre, open-label, randomised controlled trial. Lancet Diabetes Endocrinol 2020; 8:762-772. [PMID: 32822600 DOI: 10.1016/s2213-8587(20)30228-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Alkaptonuria is a rare, genetic, multisystem disease characterised by the accumulation of homogentisic acid (HGA). No HGA-lowering therapy has been approved to date. The aim of SONIA 2 was to investigate the efficacy and safety of once-daily nitisinone for reducing HGA excretion in patients with alkaptonuria and to evaluate whether nitisinone has a clinical benefit. METHODS SONIA 2 was a 4-year, open-label, evaluator-blind, randomised, no treatment controlled, parallel-group study done at three sites in the UK, France, and Slovakia. Patients aged 25 years or older with confirmed alkaptonuria and any clinical disease manifestations were randomly assigned (1:1) to receive either oral nitisinone 10 mg daily or no treatment. Patients could not be masked to treatment due to colour changes in the urine, but the study was evaluator-blinded as far as possible. The primary endpoint was daily urinary HGA excretion (u-HGA24) after 12 months. Clinical evaluation Alkaptonuria Severity Score Index (cAKUSSI) score was assessed at 12, 24, 36, and 48 months. Efficacy variables were analysed in all randomly assigned patients with a valid u-HGA24 measurement at baseline. Safety variables were analysed in all randomly assigned patients. The study was registered at ClinicalTrials.gov (NCT01916382). FINDINGS Between May 7, 2014, and Feb 16, 2015, 139 patients were screened, of whom 138 were included in the study, with 69 patients randomly assigned to each group. 55 patients in the nitisinone group and 53 in the control group completed the study. u-HGA24 at 12 months was significantly decreased by 99·7% in the nitisinone group compared with the control group (adjusted geometric mean ratio of nitisinone/control 0·003 [95% CI 0·003 to 0·004], p<0·0001). At 48 months, the increase in cAKUSSI score from baseline was significantly lower in the nitisinone group compared with the control group (adjusted mean difference -8·6 points [-16·0 to -1·2], p=0·023). 400 adverse events occurred in 59 (86%) patients in the nitisinone group and 284 events occurred in 57 (83%) patients in the control group. No treatment-related deaths occurred. INTERPRETATION Nitisinone 10 mg daily was well tolerated and effective in reducing urinary excretion of HGA. Nitisinone decreased ochronosis and improved clinical signs, indicating a slower disease progression. FUNDING European Commission Seventh Framework Programme.
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Affiliation(s)
- Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK; Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
| | | | | | - Daniela Braconi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Michael Briggs
- Department of Ophthalmology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Nadia Loftus
- Department of Physiotherapy, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Helen Bygott
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Trevor F Cox
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, UK
| | - Andrew S Davison
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Jane P Dillon
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Michael Fisher
- Department of Cardiology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Richard FitzGerald
- Department of Clinical Pharmacology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Helena Glasova
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; Institute of Pharmacology and Clinical Pharmacology, Slovak Medical University, Bratislava, Slovakia
| | | | - Andrew T Hughes
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Juliette H Hughes
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Richard Imrich
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | - Jonathan C Jarvis
- School of Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - Milad Khedr
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | | | - Emily Luangrath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Ol'ga Lukáčová
- National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | - Anna M Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Alpesh Mistry
- Department of Radiology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Brendan P Norman
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | | | - Nicholas P Rhodes
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Jozef Rovenský
- National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | | | - Annalisa Santucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Ella Shweihdi
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Jana Sedláková
- National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | | | - Roman Stančík
- National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | | | - Sophie Taylor
- Department of Physiotherapy, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Sobhan Vinjamuri
- Department of Nuclear Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Eva Vrtíková
- National Institute of Rheumatic Diseases, Piešt'any, Slovakia
| | - Chris Webb
- Department of Ear, Nose and Throat, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Elizabeth West
- Department of Dermatology, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | | | - Andrea Zatkova
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - James A Gallagher
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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Hughes JH, Liu K, Plagge A, Wilson PJM, Sutherland H, Norman BP, Hughes AT, Keenan CM, Milan AM, Sakai T, Ranganath LR, Gallagher JA, Bou-Gharios G. Conditional targeting in mice reveals that hepatic homogentisate 1,2-dioxygenase activity is essential in reducing circulating homogentisic acid and for effective therapy in the genetic disease alkaptonuria. Hum Mol Genet 2020; 28:3928-3939. [PMID: 31600782 PMCID: PMC7073386 DOI: 10.1093/hmg/ddz234] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/05/2019] [Accepted: 09/07/2019] [Indexed: 11/14/2022] Open
Abstract
Alkaptonuria is an inherited disease caused by homogentisate 1,2-dioxygenase (HGD) deficiency. Circulating homogentisic acid (HGA) is elevated and deposits in connective tissues as ochronotic pigment. In this study, we aimed to define developmental and adult HGD tissue expression and determine the location and amount of gene activity required to lower circulating HGA and rescue the alkaptonuria phenotype. We generated an alkaptonuria mouse model using a knockout-first design for the disruption of the HGD gene. Hgd tm1a −/− mice showed elevated HGA and ochronosis in adulthood. LacZ staining driven by the endogenous HGD promoter was localised to only liver parenchymal cells and kidney proximal tubules in adulthood, commencing at E12.5 and E15.5 respectively. Following removal of the gene trap cassette to obtain a normal mouse with a floxed 6th HGD exon, a double transgenic was then created with Mx1-Cre which conditionally deleted HGD in liver in a dose dependent manner. 20% of HGD mRNA remaining in liver did not rescue the disease, suggesting that we need more than 20% of liver HGD to correct the disease in gene therapy. Kidney HGD activity which remained intact reduced urinary HGA, most likely by increased absorption, but did not reduce plasma HGA nor did it prevent ochronosis. In addition, downstream metabolites of exogenous 13C6-HGA, were detected in heterozygous plasma, revealing that hepatocytes take up and metabolise HGA. This novel alkaptonuria mouse model demonstrated the importance of targeting liver for therapeutic intervention, supported by our observation that hepatocytes take up and metabolise HGA.
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Affiliation(s)
- Juliette H Hughes
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Ke Liu
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Antonius Plagge
- Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GA, UK
| | - Peter J M Wilson
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Hazel Sutherland
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Brendan P Norman
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Andrew T Hughes
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK.,Liverpool Clinical Laboratories, Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospitals Trust, Liverpool, L7 8XP, UK
| | - Craig M Keenan
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Anna M Milan
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK.,Liverpool Clinical Laboratories, Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospitals Trust, Liverpool, L7 8XP, UK
| | - Takao Sakai
- Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3GA, UK
| | - Lakshminarayan R Ranganath
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK.,Liverpool Clinical Laboratories, Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospitals Trust, Liverpool, L7 8XP, UK
| | - James A Gallagher
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - George Bou-Gharios
- Institute of Ageing and Chronic disease, University of Liverpool, Liverpool, L7 8TX, UK
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Schiavone ML, Millucci L, Bernardini G, Giustarini D, Rossi R, Marzocchi B, Santucci A. Homogentisic acid affects human osteoblastic functionality by oxidative stress and alteration of the Wnt/β-catenin signaling pathway. J Cell Physiol 2020; 235:6808-6816. [PMID: 31989660 DOI: 10.1002/jcp.29575] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/13/2020] [Indexed: 11/07/2022]
Abstract
Alkaptonuria (AKU) is a rare disease correlated with deficiency of the enzyme homogentisate 1,2 dioxygenase, which causes homogentisic acid (HGA) accumulation. HGA is subjected to oxidation/polymerization reactions, leading to the production of a peculiar melanin-like pigmentation (ochronosis) after chronic inflammation, which is considered as a triggering event for the generation of oxidative stress. Clinical manifestations of AKU are urine darkening, sclera pigmentation, early severe osteoarthropathy, and cardiovascular and renal complication. Despite major clinical manifestations of AKU being observed in the bones and skeleton, the molecular and functional parameters are so far unknown in AKU. In the present study, we used human osteoblasts supplemented with HGA as a AKU cellular model. We observed marked oxidative stress, and for the first time, we were able to correlate HGA deposition with an impairment in the Wnt/β-catenin signaling pathway, opening a range of possible therapeutic strategies for a disease still lacking a known cure.
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Affiliation(s)
- Maria Lucia Schiavone
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Lia Millucci
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Giulia Bernardini
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Daniela Giustarini
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Ranieri Rossi
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Barbara Marzocchi
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Annalisa Santucci
- Dipartimento di Eccellenza in Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
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11
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Zatkova A, Ranganath L, Kadasi L. Alkaptonuria: Current Perspectives. APPLICATION OF CLINICAL GENETICS 2020; 13:37-47. [PMID: 32158253 PMCID: PMC6986890 DOI: 10.2147/tacg.s186773] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/04/2019] [Indexed: 12/13/2022]
Abstract
The last 15 years have been the most fruitful in the history of research on the metabolic disorder alkaptonuria (AKU). AKU is caused by a deficiency of homogentisate dioxygenase (HGD), the enzyme involved in metabolism of tyrosine, and is characterized by the presence of dark ochronotic pigment in the connective tissue that is formed, due to high levels of circulating homogentisic acid. Almost 120 years ago, Sir Archibald Garrod used AKU to illustrate the concept of Mendelian inheritance in man. In January 2019, the phase III clinical study SONIA 2 was completed, which tested the effectiveness and safety of nitisinone in the treatment of AKU. Results were positive, and they will serve as the basis for the application for registration of nitisinone for treatment of AKU at the European Medicines Agency. Therefore, AKU might become a rare disease for which a cure will be found by 2020. We understand the natural history of the disease and the process of ochronosis much more, but at the same time there are still unanswered questions. One of them is the issue of the factors influencing the varying severity of the disease, since our recent genotype–phenotype study did not show that differences in residual homogentisic acid activity caused by the different mutations was responsible. Although nitisinone has proved to arrest the process of ochronosis, it has some unwanted effects and does not cure the disease completely. As such, enzyme replacement or gene therapy might become a new focus of AKU research, for which a novel suitable mouse model of AKU is available already. We believe that the story of AKU is also a story of effective collaboration between scientists and patients that might serve as an example for other rare diseases.
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Affiliation(s)
- Andrea Zatkova
- Department of Human Genetics, Biomedical Research Center, Slovak Academy of Sciences, Institute of Clinical and Translational Research, Bratislava, Slovakia
| | | | - Ludevit Kadasi
- Department of Human Genetics, Biomedical Research Center, Slovak Academy of Sciences, Institute of Clinical and Translational Research, Bratislava, Slovakia.,Faculty of Natural Sciences, Department of Molecular Biology, Comenius University, Bratislava, Slovakia
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12
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Davison AS, Hughes AT, Milan AM, Sireau N, Gallagher JA, Ranganath LR. Alkaptonuria – Many questions answered, further challenges beckon. Ann Clin Biochem 2019; 57:106-120. [DOI: 10.1177/0004563219879957] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alkaptonuria is an iconic rare inherited inborn error of metabolism affecting the tyrosine metabolic pathway, resulting in the accumulation of homogentisic acid in the circulation, and significant excretion in urine. Dating as far back as 1500 BC in the Egyptian mummy Harwa, homogentisic acid was shown to be central to the pathophysiology of alkaptonuria through its deposition in collagenous tissues in a process termed ochronosis. Clinical manifestations occurring as a consequence of this are typically observed from the third decade of life, are lifelong and significantly affect the quality of life. In large supportive and palliative treatment measures are available to patients, including analgesia, physiotherapy and joint replacement. Studying the natural history of alkaptonuria, in a murine model and human subjects, has provided key insights into the biochemical and molecular mechanisms underlying the pathophysiology associated with the disease, and has enabled a better understanding of the common disease osteoarthritis. In the last decade, a major focus has been on an unlicensed disease-modifying therapy called nitisinone. This has been shown to be highly efficacious in reducing homogentisic acid, and it is hoped this will halt ochronosis, thus limiting the clinical complications associated with the disease. A well-documented metabolic consequence of nitisinone therapy is hypertyrosinaemia, the clinical implications of which are uncertain. Recent metabolomic studies have helped understand the wider metabolic consequences of nitisinone therapy.
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Affiliation(s)
- AS Davison
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK
| | - AT Hughes
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK
| | - AM Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK
| | | | - JA Gallagher
- Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK
| | - LR Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK
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13
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Taylor AM, Shepherd L. The potential of nitisinone for the treatment of alkaptonuria. Expert Opin Orphan Drugs 2019. [DOI: 10.1080/21678707.2019.1664899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Adam M Taylor
- Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Laura Shepherd
- Lancaster Medical School, Lancaster University, Lancaster, UK
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14
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Ranganath LR, Norman BP, Gallagher JA. Ochronotic pigmentation is caused by homogentisic acid and is the key event in alkaptonuria leading to the destructive consequences of the disease-A review. J Inherit Metab Dis 2019; 42:776-792. [PMID: 31282009 DOI: 10.1002/jimd.12152] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 02/06/2023]
Abstract
Ochronosis is the process in alkaptonuria (AKU) that causes all the debilitating morbidity. The process involves selective deposition of homogentisic acid (HGA)-derived pigment in tissues altering the properties of these tissues, leading to their failure. Some tissues like cartilage are more easily affected by ochronosis while others such as the liver and brain are unaffected for reasons that are still not understood. In vitro and mouse models of ochronosis have confirmed the dose relationships between HGA and ochronosis and also their modulation by p-hydroxyphenylpyruvate dioxygenase inhibition. Ochronosis cannot be fully reversed and is a key factor in influencing treatment decisions. Earlier detection of ochronosis preferably by noninvasive means is desirable. A cause-effect relationship between HGA and ochronosis is discussed. The similarity in AKU and familial hypercholesterolaemia is explored and lessons learnt. More research is needed to more fully understand the crucial nature of ochronosis.
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Affiliation(s)
- Lakshminarayan R Ranganath
- Royal Liverpool University Hospital, Liverpool, UK
- Musculoskeletal Biology I, Institute of Ageing & Chronic Disease, William Henry Duncan Building, University of Liverpool, Liverpool, UK
| | - Brendan P Norman
- Musculoskeletal Biology I, Institute of Ageing & Chronic Disease, William Henry Duncan Building, University of Liverpool, Liverpool, UK
| | - James A Gallagher
- Musculoskeletal Biology I, Institute of Ageing & Chronic Disease, William Henry Duncan Building, University of Liverpool, Liverpool, UK
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15
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Keenan CM, Beckett AJ, Sutherland H, Ranganath LR, Jarvis JC, Prior IA, Gallagher JA. Concentric lamellae - novel microanatomical structures in the articular calcified cartilage of mice. Sci Rep 2019; 9:11188. [PMID: 31371812 PMCID: PMC6671989 DOI: 10.1038/s41598-019-47545-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/10/2019] [Indexed: 12/15/2022] Open
Abstract
The structure, ultrastructure and function of hyaline articular cartilage (HAC) and subchondral bone (SCB), and their involvement in the pathogenesis of osteoarthritis (OA) have been extensively researched. However, much less attention has been focused on the intervening tissue, articular calcified cartilage (ACC) and its role in the initiation and progression of OA. Using both light microscopy (LM) and transmission electron microscopy (TEM), a study of ACC in wild type (WT) mice, and mice with genetic osteoarthropathies (AKU) was undertaken to further understand the role played by ACC in the early stages of OA.Tibio-femoral joints were obtained from BALB/c WT and BALB/c AKU mice aged between 7 and 69 weeks. One joint was processed for routine histological analysis. The tip of the medial femoral condyle (MFC), which contained HAC, ACC, and SCB, was dissected from the contra-lateral joint and processed for TEM.In WT and AKU mice novel microanatomical structures, designated concentric lamellae, were identified surrounding chondrocytes in the ACC. The lamellae appeared to be laid down in association with advancement of the tidemark indicating they may be formed during calcification of cartilage matrix. The lamellae were associated with hypertrophic chondrocytes throughout the ACC.Novel microanatomical structures, termed concentric lamellae, which were present around hypertrophic chondrocytes in the ACC are described for the first time. Their apparent association with mineralisation, advancement of the tidemark, and greater abundance in a model of osteoarthropathy indicate their formation could be important in the pathogenesis of OA and AKU.
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Affiliation(s)
- Craig M Keenan
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, West Derby Street, Liverpool, L7 8TX, UK.
| | - Alison J Beckett
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Nuffield Building, Crown Street, Liverpool, L69 3BX, UK
| | - Hazel Sutherland
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, West Derby Street, Liverpool, L7 8TX, UK.,School of Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Lakshminarayan R Ranganath
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, West Derby Street, Liverpool, L7 8TX, UK.,Department of Clinical Biochemistry and Metabolism, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP, UK
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Ian A Prior
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Nuffield Building, Crown Street, Liverpool, L69 3BX, UK
| | - James A Gallagher
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, West Derby Street, Liverpool, L7 8TX, UK.
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16
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Milan AM, Hughes AT, Davison AS, Devine J, Usher J, Curtis S, Khedr M, Gallagher JA, Ranganath LR. The effect of nitisinone on homogentisic acid and tyrosine: a two-year survey of patients attending the National Alkaptonuria Centre, Liverpool. Ann Clin Biochem 2017; 54:323-330. [DOI: 10.1177/0004563217691065] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Alkaptonuria is a rare, debilitating autosomal recessive disorder affecting tyrosine metabolism. Deficiency of homogentisate 1,2-dioxygenase leads to increased homogentisic acid which is deposited as ochronotic pigment. Clinical sequelae include severe early onset osteoarthritis, increased renal and prostate stone formation and cardiac complications. Treatment has been largely based on analgaesia and arthroplasty. The National Alkaptonuria Centre in Liverpool has been using 2 mg nitisinone (NTBC) off-license for all patients in the United Kingdom with alkaptonuria and monitoring the tyrosine metabolite profiles. Methods Patients with confirmed alkaptonuria are commenced on 2 mg dose (alternative days) of NTBC for three months with daily dose thereafter. Metabolite measurement by LC-MS/MS is performed at baseline, day 4, three-months, six-months and one-year post-commencing NTBC. Thereafter, monitoring and clinical assessments are performed annually. Results Urine homogentisic acid concentration decreased from a mean baseline 20,557 µmol/24 h (95th percentile confidence interval 18,446–22,669 µmol/24 h) by on average 95.4% by six months, 94.8% at one year and 94.1% at two year monitoring. A concurrent reduction in serum homogentisic acid concentration of 83.2% compared to baseline was also measured. Serum tyrosine increased from normal adult reference interval to a mean ± SD of 594 ± 184 µmol /L at year-two monitoring with an increased urinary excretion from 103 ± 81 µmol /24 h at baseline to 1071 ± 726 µmol /24 h two years from therapy. Conclusions The data presented represent the first longitudinal survey of NTBC use in an NHS service setting and demonstrate the sustained effect of NTBC on the tyrosine metabolite profile.
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Affiliation(s)
- Anna M Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Andrew T Hughes
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Andrew S Davison
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Jean Devine
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Jeannette Usher
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
| | - Sarah Curtis
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
| | - Milad Khedr
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
| | - James A Gallagher
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, UK
- Bone and Joint Research Group, Musculoskeletal Biology, University of Liverpool, Liverpool, UK
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17
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Geminiani M, Gambassi S, Millucci L, Lupetti P, Collodel G, Mazzi L, Frediani B, Braconi D, Marzocchi B, Laschi M, Bernardini G, Santucci A. Cytoskeleton Aberrations in Alkaptonuric Chondrocytes. J Cell Physiol 2017; 232:1728-1738. [DOI: 10.1002/jcp.25500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/22/2016] [Indexed: 01/30/2023]
Affiliation(s)
- Michela Geminiani
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Silvia Gambassi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Lia Millucci
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Pietro Lupetti
- Dipartimento di Scienze della Vita; Università degli Studi di Siena; Siena Italy
| | - Giulia Collodel
- Dipartimento di Medicina Molecolare e dello Sviluppo; Università degli Studi di Siena; Siena Italy
| | - Lucia Mazzi
- Dipartimento di Medicina Molecolare e dello Sviluppo; Università degli Studi di Siena; Siena Italy
| | - Bruno Frediani
- Dipartimento di Scienze Mediche; Chirurgiche e Neuroscienze; Università degli Studi di Siena; Siena Italy
| | - Daniela Braconi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Barbara Marzocchi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Marcella Laschi
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Giulia Bernardini
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
| | - Annalisa Santucci
- Dipartimento di Biotecnologie; Chimica e Farmacia; Università degli Studi di Siena; Siena Italy
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18
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Taylor AM, Hsueh MF, Ranganath LR, Gallagher JA, Dillon JP, Huebner JL, Catterall JB, Kraus VB. Cartilage biomarkers in the osteoarthropathy of alkaptonuria reveal low turnover and accelerated ageing. Rheumatology (Oxford) 2017; 56:156-164. [PMID: 28028161 PMCID: PMC5188995 DOI: 10.1093/rheumatology/kew355] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 08/24/2016] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Alkaptonuria (AKU) is a rare autosomal recessive disease resulting from a single enzyme deficiency in tyrosine metabolism. As a result, homogentisic acid cannot be metabolized, causing systemic increases. Over time, homogentisic acid polymerizes and deposits in collagenous tissues, leading to ochronosis. Typically, this occurs in joint cartilages, leading to an early onset, rapidly progressing osteoarthropathy. The aim of this study was to examine tissue turnover in cartilage affected by ochronosis and its role in disease initiation and progression. METHODS With informed patient consent, hip and knee cartilages were obtained at surgery for arthropathy due to AKU (n = 6; 2 knees/4 hips) and OA (n = 12; 5 knees/7 hips); healthy non-arthritic (non-OA n = 6; 1 knee/5 hips) cartilages were obtained as waste from trauma surgery. We measured cartilage concentrations (normalized to dry weight) of racemized aspartate, GAG, COMP and deamidated COMP (D-COMP). Unpaired AKU, OA and non-OA samples were compared by non-parametric Mann-Whitney U test. RESULTS Despite more extractable total protein being obtained from AKU cartilage than from OA or non-OA cartilage, there was significantly less extractable GAG, COMP and D-COMP in AKU samples compared with OA and non-OA comparators. Racemized Asx (aspartate and asparagine) was significantly enriched in AKU cartilage compared with in OA cartilage. CONCLUSIONS These novel data represent the first examination of cartilage matrix components in a sample of patients with AKU, representing almost 10% of the known UK alkaptonuric population. Compared with OA and non-OA, AKU cartilage demonstrates a very low turnover state and has low levels of extractable matrix proteins.
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Affiliation(s)
- Adam M Taylor
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, UK
- Department of Medicine, Duke University School of Medicine, Duke Molecular Physiology Institute
| | - Ming-Feng Hsueh
- Department of Pathology, Duke University School of Medicine, Durham, NC, USA
| | | | | | - Jane P Dillon
- Musculoskeletal Biology, University of Liverpool, Liverpool, UK
| | - Janet L Huebner
- Department of Medicine, Duke University School of Medicine, Duke Molecular Physiology Institute
| | - Jon B Catterall
- Department of Medicine, Duke University School of Medicine, Duke Molecular Physiology Institute
| | - Virginia B Kraus
- Department of Medicine, Duke University School of Medicine, Duke Molecular Physiology Institute
- Department of Pathology, Duke University School of Medicine, Durham, NC, USA
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC, USA
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19
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Analysis of Melanin-like Pigment Synthesized from Homogentisic Acid, with or without Tyrosine, and Its Implications in Alkaptonuria. JIMD Rep 2016; 35:79-85. [PMID: 27943071 DOI: 10.1007/8904_2016_27] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/02/2016] [Accepted: 11/16/2016] [Indexed: 12/12/2022] Open
Abstract
Alkaptonuria is an iconic disease used by Archibald Garrod to demonstrate the theory of "inborn errors of metabolism". AKU knowledge has advanced in recent years: development of an in vitro model, discovery of murine models and advances in understanding bone and cartilage phenotypes and arthropathy in AKU. These discoveries have aided in a new clinical trial into nitisinone. However, there are still knowledge gaps surrounding the pigment in AKU and the pigmentation process. We demonstrate an advance in the understanding in the kinetics and chemistry of the polymerisation of homogentisic acid (HGA) into its pigment using size-exclusion chromatography and IR spectroscopy. We compared the properties of HGA-based pigments that were freshly prepared to those stored in solution for 2 years. Our results demonstrate the importance of pH in the polymerisation process and that colour change seen in solution (analogous to AKU patient urine) is not initially due to presence of ochronotic pigment but the quinone intermediary. In addition, we observed that pigment formation from HGA can occur in the presence of tyrosine, without the inclusion of this tyrosine into the pigment. These observations have positive implications for patients with alkaptonuria; an increased understanding of the pigment polymer chemistry, the presence of an intermediary and their kinetics present more therapeutic opportunities for treating the condition, including preventing the pigment from forming, binding or reversing established pigmentation. AKU patients treated with nitisinone show elevated tyrosine levels causing side effects such as corneal opacities; our data demonstrates that elevated tyrosine levels should not contribute or add to the ochronotic pigment burden in these patients.
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20
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Millucci L, Bernardini G, Marzocchi B, Braconi D, Geminiani M, Gambassi S, Laschi M, Frediani B, Galvagni F, Orlandini M, Santucci A. Angiogenesis in alkaptonuria. J Inherit Metab Dis 2016; 39:801-806. [PMID: 27671890 DOI: 10.1007/s10545-016-9976-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/28/2016] [Accepted: 08/17/2016] [Indexed: 10/20/2022]
Abstract
Alkaptonuria (AKU) is a rare genetic disease that affects the entire joint. Current standard of AKU treatment is palliative and little is known about its physiopathology. Neovascularization is involved in the pathogenesis of systemic inflammatory rheumatic diseases, a family of related disorders that includes AKU. Here, we investigated the presence of neoangiogenesis in AKU synovium and healthy controls. Synovium from AKU patients, who had undergone total joint replacement or arthroscopy, or from healthy patients without any history of rheumatic diseases, who underwent surgical operation following sport trauma was subjected to hematoxylin and eosin staining. Histologic grades were assigned for clinical disease activity and synovitis based on cellular content of the synovium. By immunofluorescence microscopy, using different endothelial cell markers, we observed large vascularization in AKU but not in healthy synovium. Moreover, Western blotting and quantification analyses confirmed strong expression of endothelial cell markers in AKU synovial tissues. Importantly, AKU synovium vascular endothelium expressed high levels of β-dystroglycan, a protein previously involved in the regulation of angiogenesis in osteoarthritic synovium. This is the first report providing experimental evidences that new blood vessels are formed in AKU synovial tissues, opening new perspectives for AKU therapy.
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Affiliation(s)
- Lia Millucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Giulia Bernardini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Barbara Marzocchi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Daniela Braconi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Michela Geminiani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Silvia Gambassi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Marcella Laschi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Bruno Frediani
- Department of Medicine, Surgery and Neurosciences, Rheumatology section, University of Siena, Policlinico Le Scotte, 53100, Siena, Italy
| | - Federico Galvagni
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Maurizio Orlandini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy
| | - Annalisa Santucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. Moro, 2, 53100, Siena, Italy.
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21
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Bryan LK, Weeks BR, Payne HR, Thompson LA, Mansell JL. Ochronosis-like condition in a cat. Vet Dermatol 2016; 27:311-e77. [DOI: 10.1111/vde.12326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Laura K. Bryan
- Department of Veterinary Pathobiology; College of Veterinary Medicine and Biomedical Sciences; Texas A&M University; 4467 TAMU College Station TX 77843-4467 USA
| | - Brad R. Weeks
- Department of Veterinary Pathobiology; College of Veterinary Medicine and Biomedical Sciences; Texas A&M University; 4467 TAMU College Station TX 77843-4467 USA
| | - Harold Ross Payne
- Department of Veterinary Pathobiology; College of Veterinary Medicine and Biomedical Sciences; Texas A&M University; 4467 TAMU College Station TX 77843-4467 USA
| | - Lori A. Thompson
- Animal Dermatology Clinic; 3901 East 82nd Street Indianapolis IN 46240 USA
| | - Joanne L. Mansell
- Department of Veterinary Pathobiology; College of Veterinary Medicine and Biomedical Sciences; Texas A&M University; 4467 TAMU College Station TX 77843-4467 USA
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Bassily E, O'Dell MC, Homan B, Wasyliw C. Alkaptonuria. Orthopedics 2016; 39:e810-3. [PMID: 27158826 DOI: 10.3928/01477447-20160503-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A 50-year-old woman with a chronic polyarthropathy was seen by her orthopedist for long-standing back and shoulder and worsening hip pain. A lateral labral tear and chronic trochanteric bursitis were diagnosed on hip magnetic resonance imaging, which was otherwise unremarkable. Hip arthroscopy was performed revealing an unusual bluish-tinged femoral head articular surface. Computed tomography scans of the spine were also obtained.
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Taylor AM, Kammath V, Bleakley A. Tyrosinase, could it be a missing link in ochronosis in alkaptonuria? Med Hypotheses 2016; 91:77-80. [DOI: 10.1016/j.mehy.2016.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/03/2016] [Indexed: 02/07/2023]
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Gallagher JA, Dillon JP, Sireau N, Timmis O, Ranganath LR. Alkaptonuria: An example of a "fundamental disease"--A rare disease with important lessons for more common disorders. Semin Cell Dev Biol 2016; 52:53-7. [PMID: 26891864 DOI: 10.1016/j.semcdb.2016.02.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 01/01/2023]
Abstract
"Fundamental diseases" is a term introduced by the charity Findacure to describe rare genetic disorders that are gateways to understanding common conditions and human physiology. The concept that rare diseases have important lessons for biomedical science has been recognised by some of the great figures in the history of medical research, including Harvey, Bateson and Garrod. Here we describe some of the recently discovered lessons from the study of the iconic genetic disease alkaptonuria (AKU), which have shed new light on understanding the pathogenesis of osteoarthritis. In AKU, ochronotic pigment is deposited in cartilage when collagen fibrils become susceptible to attack by homogentisic acid (HGA). When HGA binds to collagen, cartilage matrix becomes stiffened, resulting in the aberrant transmission of loading to underlying subchondral bone. Aberrant loading leads to the formation of pathophysiological structures including trabecular excrescences and high density mineralised protrusions (HDMPs). These structures initially identified in AKU have subsequently been found in more common osteoarthritis and appear to play a role in joint destruction in both diseases.
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Affiliation(s)
- James A Gallagher
- Musculoskeletal Biology, University of Liverpool, Apex Building, Liverpool L7 8TX, UK.
| | - Jane P Dillon
- Musculoskeletal Biology, University of Liverpool, Apex Building, Liverpool L7 8TX, UK.
| | | | - Oliver Timmis
- AKU Society, 66 Devonshire Road, Cambridge CB1 2BL, UK.
| | - Lakshminarayan R Ranganath
- Musculoskeletal Biology, University of Liverpool, Apex Building, Liverpool L7 8TX, UK; Clinical Biochemistry and Metabolism, Royal Liverpool University Hospital, Prescot Street,Liverpool L7 8XP, UK.
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25
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The Distribution of Ochronosis in Osteoarthritic Articular Cartilage in a Knee. HSS J 2016; 12:76-80. [PMID: 26855632 PMCID: PMC4733698 DOI: 10.1007/s11420-015-9464-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 08/14/2015] [Indexed: 02/07/2023]
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26
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Zatkova A, Nemethova M. Genetics of alkaptonuria – an overview. ACTA FACULTATIS PHARMACEUTICAE UNIVERSITATIS COMENIANAE 2015. [DOI: 10.1515/afpuc-2015-0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Alkaptonuria (AKU) is the first described inborn error of metabolism and a classical example of rare autosomal recessive disease. AKU patients carry homozygous or compound heterozygous mutations of the gene coding for enzyme homogentisate dioxygenase (HGD) involved in metabolism of tyrosine. The metabolic block in AKU causes accumulation of homogentisic acid (HGA) that, with advancing age of the patient, leads to severe and painful ochronotic arthropathy. HGD gene was mapped to chromosome 3q13.3 and is composed of 14 exons. In about 400 patients, 142 pathogenic variants were reported that are listed in HGD mutations database (http://hgddatabase.cvtisr.sk/). In this review, we summarise different aspects of AKU genetics and impact of the HGD variants on enzyme function.
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Lessons from rare diseases of cartilage and bone. Curr Opin Pharmacol 2015; 22:107-14. [PMID: 25978274 DOI: 10.1016/j.coph.2015.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/16/2015] [Indexed: 01/09/2023]
Abstract
Studying severe phenotypes of rare syndromes can elucidate disease mechanisms of more common disorders and identify potential therapeutic targets. Lessons from rare bone diseases contributed to the development of the most successful class of bone active agents, the bisphosphonates. More recent research on rare bone diseases has helped elucidate key pathways and identify new targets in bone resorption and bone formation including cathepsin K and sclerostin, for which drugs are now in clinical trials. By contrast, there has been much less focus on rare cartilage diseases and osteoarthritis (OA) remains a common disease with no effective therapy. Investigation of rare cartilage syndromes is identifying new potential targets in OA including GDF5 and lubricin. Research on the arthropathy of the ultra-rare disease alkaptonuria has identified several new features of the OA phenotype, including high density mineralized protrusions (HDMPs) which constitute a newly identified mechanism of joint destruction.
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Keenan CM, Preston AJ, Sutherland H, Wilson PJ, Psarelli EE, Cox TF, Ranganath LR, Jarvis JC, Gallagher JA. Nitisinone Arrests but Does Not Reverse Ochronosis in Alkaptonuric Mice. JIMD Rep 2015; 24:45-50. [PMID: 25940034 DOI: 10.1007/8904_2015_437] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/13/2015] [Accepted: 03/24/2015] [Indexed: 10/23/2022] Open
Abstract
Alkaptonuria (AKU) is an ultrarare autosomal recessive disorder resulting from a deficiency of homogentisate 1,2 dioxygenase (HGD), an enzyme involved in the catabolism of phenylalanine and tyrosine. Loss of HGD function prevents metabolism of homogentisic acid (HGA), leading to increased levels of plasma HGA and urinary excretion. Excess HGA becomes deposited in collagenous tissues and subsequently undergoes polymerisation, principally in the cartilages of loaded joints, in a process known as ochronosis. This results in an early-onset, devastating osteoarthropathy for which there is currently no effective treatment. We recently described the natural history of ochronosis in a murine model of AKU, demonstrating that deposition of ochronotic pigment begins very early in life and accumulates with age. Using this model, we were able to show that lifetime treatment with nitisinone, a potential therapy for AKU, was able to completely prevent deposition of ochronotic pigment. However, although nitisinone has been shown to inhibit ochronotic deposition, whether it can also facilitate removal of existing pigment has not yet been examined. We describe here that midlife administration of nitisinone to AKU mice arrests further deposition of ochronotic pigment in the tibiofemoral joint, but does not result in the clearance of existing pigment. We also demonstrate the dose-dependent response of plasma HGA to nitisinone, highlighting its efficacy for personalised medicine, where dosage can be tailored to the individual AKU patient.
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Affiliation(s)
- Craig M Keenan
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, UK
| | - Andrew J Preston
- Developmental Immunology, Paediatrics, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
| | - Hazel Sutherland
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, UK.,School of Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Buildings, Byrom Street, Liverpool, L3 3AF, UK
| | - Peter J Wilson
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, UK
| | - Eftychia E Psarelli
- Cancer Research UK Liverpool Cancer Trials Unit, University of Liverpool, 1-3 Brownlow Street, Liverpool, L69 3GL, UK
| | - Trevor F Cox
- Cancer Research UK Liverpool Cancer Trials Unit, University of Liverpool, 1-3 Brownlow Street, Liverpool, L69 3GL, UK
| | - Lakshminarayan R Ranganath
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, UK.,Department of Clinical Biochemistry and Metabolism, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP, UK
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Buildings, Byrom Street, Liverpool, L3 3AF, UK
| | - James A Gallagher
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool, L69 3GE, UK.
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Ranganath LR, Psarelli EE, Cox TF, Gallagher JA. Diagnostic tools and strategies for assessing disease progression in Alkaptonuria. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1042859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Investigating the Robustness and Diagnostic Potential of Extracellular Matrix Remodelling Biomarkers in Alkaptonuria. JIMD Rep 2015; 24:29-37. [PMID: 25786641 DOI: 10.1007/8904_2015_430] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/09/2015] [Accepted: 02/23/2015] [Indexed: 03/07/2023] Open
Abstract
BACKGROUND AND AIM Alkaptonuria (AKU) clinical manifestations resemble severe arthritis. The Suitability of Nitisinone in Alkaptonuria 1 (SONIA 1) study is a dose-finding trial for nitisinone treatment of AKU patients. We tested a panel of serum and urinary biomarkers reflecting extracellular matrix remodelling (ECMR) of cartilage, bone and connective tissue in SONIA 1 patients to identify non-invasive and diagnostic biomarkers of tissue turnover in AKU. METHODS Fasted serum and urine were retrieved from 40 SONIA 1 patients and 44 healthy controls. Established biomarkers of bone remodelling (CTX-I, P1NP, OC), cartilage remodelling (CTX-II, C2M, AGNx1) and inflammation (CRPM) as well as exploratory biomarkers of ECMR (C6M, VCANM, MIM, TIM) were measured at baseline in serum and urine by means of enzyme-linked immunosorbent assays (ELISAs) or automated systems (Elecsys 2010). RESULTS The levels of bone resorption (CTX-I) and cartilage degradation (C2M) were elevated in AKU patients as compared to controls (p > 0.0001 and p = 0.03, respectively). Also tissue inflammation (CRPM) was elevated in AKU patients (p = 0.01). In addition all four exploratory biomarkers of ECMR (C6M, VCANM, MIM, TIM) were elevated in AKU patients compared to healthy controls. CTX-II was the only biomarker to be reduced in AKU patients. TIM was the only marker that showed a higher concentration than the normal assay range in AKU patients. CONCLUSIONS We have identified new potential biomarkers for assessment of cartilage, bone and cardiovascular remodelling in AKU and demonstrated the robustness of the assays used to measure the biomarker concentration in biological fluids.
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Doganavsargil B, Pehlivanoglu B, Bicer EK, Argin M, Bingul KB, Sezak M, Kececi B, Coker M, Oztop F. Black joint and synovia: Histopathological evaluation of degenerative joint disease due to Ochronosis. Pathol Res Pract 2015; 211:470-7. [PMID: 25869213 DOI: 10.1016/j.prp.2015.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 02/25/2015] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Ochronotic arthropathy is a rapidly progressive and disabling arthropathy predominantly encountered after the fifth decade of life, caused by homogentisate1,2 dioxygenase enzyme deficiency. As it is rare disease, the literature on histological findings is fragmented. MATERIALS AND METHODS We retrospectively re-evaluated histopathological findings in resection and/or curettage materials (5 hip joint, 4 knee joint, one hip joint synovium, one intervertebral disk and one paravertebral disk tissue) of seven ochronosis cases diagnosed between 1995 and 2013 in a single center. RESULTS Necrotic brown chondroid detritus was present in all cases either in synovia or in subchondral area, some of which evoked giant cell reaction. Notably, brown pigmentation was prominent in upper middle parts of the articular cartilage but not that prominent in superficial parts and in osteochondral junction, almost stopping at the tide mark. Pigmentation was observed both in extracellular matrix and in cytoplasm either in granular or homogeneous fashion. Depositions were less prominent in osteophytic processes, regenerated cartilaginous areas and loose bodies. Almost all cases showed synovial detritic and inflammatory reaction, fibrillation, eburnation, and subchondral sclerosis. Disk degeneration and findings of ligament rupture were also observed. CONCLUSIONS Histopathological diagnosis of ochronosis is not complicated given the unique "black coloring" of the affected tissues and it can easily be differentiated from other causes of detritic synovitis both clinically and histopathologically. However, there is no definitive cure for today and the reasons for late onset of arthropathy in disease course, and the mechanisms of tissue reaction to fragmented detritus remain elusive.
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Affiliation(s)
| | | | - Elcil Kaya Bicer
- Ege University Faculty of Medicine, Department of Orthopedics, Izmir, Turkey
| | - Mehmet Argin
- Ege University Faculty of Medicine, Department of Radiodiagnostics, Izmir, Turkey
| | - Kenan Baris Bingul
- Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey
| | - Murat Sezak
- Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey
| | - Burcin Kececi
- Ege University Faculty of Medicine, Department of Orthopedics, Izmir, Turkey
| | - Mahmut Coker
- Ege University Faculty of Medicine, Department of Paediatric Endocrinology and Metabolism, Izmir, Turkey
| | - Fikri Oztop
- Ege University Faculty of Medicine, Department of Pathology, Izmir, Turkey
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Analysis of HGD Gene Mutations in Patients with Alkaptonuria from the United Kingdom: Identification of Novel Mutations. JIMD Rep 2015; 24:3-11. [PMID: 25681086 DOI: 10.1007/8904_2014_380] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/23/2014] [Accepted: 11/03/2014] [Indexed: 12/24/2022] Open
Abstract
Alkaptonuria (AKU) is a rare autosomal recessive disorder with incidence ranging from 1:100,000 to 1:250,000. The disorder is caused by a deficiency of the enzyme homogentisate 1,2-dioxygenase (HGD), which results from defects in the HGD gene. This enzyme converts homogentisic acid to maleylacetoacetate and has a major role in the catabolism of phenylalanine and tyrosine. To elucidate the mutation spectrum of the HGD gene in patients with alkaptonuria from 42 patients attending the National Alkaptonuria Centre, 14 exons of the HGD gene and the intron-exon boundaries were analysed by PCR-based sequencing. A total of 34 sequence variants was observed, confirming the genetic heterogeneity of AKU. Of these mutations, 26 were missense substitutions and four splice site mutations. There were two deletions and one duplication giving rise to frame shifts and one substitution abolishing the translation termination codon (no stop). Nine of the mutations were previously unreported novel variants. Using computational approaches based on the 3D structure, these novel mutations are predicted to affect the activity of the protein complex through destabilisation of the individual protomer structure or through disruption of protomer-protomer interactions.
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Hughes AT, Milan AM, Davison AS, Christensen P, Ross G, Gallagher JA, Dutton JJ, Ranganath LR. Serum markers in alkaptonuria: simultaneous analysis of homogentisic acid, tyrosine and nitisinone by liquid chromatography tandem mass spectrometry. Ann Clin Biochem 2015; 52:597-605. [PMID: 25628464 DOI: 10.1177/0004563215571969] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Alkaptonuria is a rare debilitating autosomal recessive disorder of tyrosine metabolism, where deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid. Homogentisic acid is deposited as an ochronotic pigment in connective tissues, especially cartilage, leading to a severe early onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, nitisinone, an inhibitor of 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of homogentisic acid. METHOD A reverse phase liquid chromatography tandem mass spectrometry method has been developed to simultaneously analyse serum homogentisic acid, tyrosine and nitisinone. Using matrix-matched calibration standards, two product ion transitions were identified for each compound (homogentisic acid, tyrosine, nitisinone) and their respective isotopically labelled internal standards ((13)C6-homogentisic acid, d2-tyrosine, (13)C6-nitisinone). RESULTS Intrabatch accuracy was 94-108% for homogentisic acid, 95-109% for tyrosine and 89-106% for nitisinone; interbatch accuracy (n = 20) was 88-108% for homogentisic acid, 91-104% for tyrosine and 88-103% for nitisinone. Precision, both intra- and interbatch were <12% for homogentisic acid and tyrosine, and <10% for nitisinone. Matrix effects observed with acidified serum were normalized by the internal standard (<10% coefficient of variation). Homogentisic acid, tyrosine and nitisinone proved stable after 24 h at room temp, three freeze-thaw cycles and 24 h at 4℃. The assay was linear to 500μmol/L homogentisic acid, 2000μmol/L tyrosine and 10μmol/L nitisinone; increased range was not required for clinical samples and no carryover was observed. CONCLUSIONS The method developed and validated shows good precision, accuracy and linearity appropriate for the monitoring of alkaptonuria patients, pre- and post-nitisinone therapy.
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Affiliation(s)
- Andrew T Hughes
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool and Broadgreen University Hospital Trust, Liverpool, UK Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool, UK
| | - Anna M Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool and Broadgreen University Hospital Trust, Liverpool, UK Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool, UK
| | - Andrew S Davison
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool and Broadgreen University Hospital Trust, Liverpool, UK
| | | | | | - James A Gallagher
- Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool, UK
| | - John J Dutton
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool and Broadgreen University Hospital Trust, Liverpool, UK
| | - Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool and Broadgreen University Hospital Trust, Liverpool, UK Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool, UK
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Kraus VB. Rare osteoarthritis. Rheumatology (Oxford) 2015. [DOI: 10.1016/b978-0-323-09138-1.00185-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Braconi D, Millucci L, Ghezzi L, Santucci A. Redox proteomics gives insights into the role of oxidative stress in alkaptonuria. Expert Rev Proteomics 2014; 10:521-35. [PMID: 24206226 DOI: 10.1586/14789450.2013.858020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alkaptonuria (AKU) is an ultra-rare metabolic disorder of the catabolic pathway of tyrosine and phenylalanine that has been poorly characterized at molecular level. As a genetic disease, AKU is present at birth, but its most severe manifestations are delayed due to the deposition of a dark-brown pigment (ochronosis) in connective tissues. The reasons for such a delayed manifestation have not been clarified yet, though several lines of evidence suggest that the metabolite accumulated in AKU sufferers (homogentisic acid) is prone to auto-oxidation and induction of oxidative stress. The clarification of the pathophysiological molecular mechanisms of AKU would allow a better understanding of the disease, help find a cure for AKU and provide a model for more common rheumatic diseases. With this aim, we have shown how proteomics and redox proteomics might successfully overcome the difficulties of studying a rare disease such as AKU and the limitations of the hitherto adopted approaches.
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Affiliation(s)
- Daniela Braconi
- Dipartimento di Biotecnologie, Chimica e Farmacia, via Fiorentina 1, Università degli Studi di Siena, 53100 Siena, Italy
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Hughes AT, Milan AM, Christensen P, Ross G, Davison AS, Gallagher JA, Dutton JJ, Ranganath LR. Urine homogentisic acid and tyrosine: simultaneous analysis by liquid chromatography tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 963:106-12. [PMID: 24952314 DOI: 10.1016/j.jchromb.2014.06.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/28/2014] [Accepted: 06/01/2014] [Indexed: 11/17/2022]
Abstract
Alkaptonuria (AKU) is a rare debilitating autosomal recessive disorder of tyrosine metabolism. Deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid (HGA) which although excreted in gram quantities in the urine, is deposited as an ochronotic pigment in connective tissues, especially cartilage. Ochronosis leads to a severe, early-onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, Nitisinone, an inhibitor of the enzyme 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of HGA, resulting in accumulation of the upstream pre-cursor, tyrosine. Using reverse phase LC-MS/MS, a method has been developed to simultaneously quantify urinary HGA and tyrosine. Using matrix-matched calibration standards, two product ion transitions were identified for each compound and their appropriate isotopically labelled internal standards. Validation was performed across the AKU and post-treatment concentrations expected. Intrabatch accuracy for acidified urine was 96-109% for tyrosine and 94-107% for HGA; interbatch accuracy (n=20 across ten assays) was 95-110% for tyrosine and 91-109% for HGA. Precision, both intra- and interbatch was <10% for tyrosine and <5% for HGA. Matrix effects observed with acidified urine (12% decrease, CV 5.6%) were normalised by the internal standard. Tyrosine and HGA were proved stable under various storage conditions and no carryover, was observed. Overall the method developed and validated shows good precision, accuracy and linearity appropriate for the monitoring of patients with AKU, pre and post-nitisinone therapy.
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Affiliation(s)
- A T Hughes
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital Trust, Duncan Building, Liverpool L7 8XP, United Kingdom; Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - A M Milan
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital Trust, Duncan Building, Liverpool L7 8XP, United Kingdom; Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool L69 3GE, United Kingdom.
| | - P Christensen
- Agilent Technologies, 5500 Lakeside, Cheadle Royal Business Park, Cheadle, Stockport SK8 3GR, United Kingdom
| | - G Ross
- Agilent Technologies, 5500 Lakeside, Cheadle Royal Business Park, Cheadle, Stockport SK8 3GR, United Kingdom
| | - A S Davison
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital Trust, Duncan Building, Liverpool L7 8XP, United Kingdom
| | - J A Gallagher
- Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - J J Dutton
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital Trust, Duncan Building, Liverpool L7 8XP, United Kingdom
| | - L R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool and Broadgreen University Hospital Trust, Duncan Building, Liverpool L7 8XP, United Kingdom; Bone and Joint Research Group, Musculoskeletal Biology, Sherrington Building, University of Liverpool, Liverpool L69 3GE, United Kingdom
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Treatment of nongout joint deposition diseases: an update. ARTHRITIS 2014; 2014:375202. [PMID: 24895535 PMCID: PMC4034491 DOI: 10.1155/2014/375202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 04/24/2014] [Indexed: 12/16/2022]
Abstract
This update develops the actual therapeutic options in the management of the joint involvement of calcium pyrophosphate deposition disease (CPPD), basic calcium phosphate (BCP) deposition disease, hemochromatosis (HH), ochronosis, oxalosis, and Wilson's disease. Conventional pharmaceutical treatment provides benefits for most diseases. Anti-interleukine-1 (IL-1) treatment could provide similar results in CPPD than in gout flares. There is only limited evidence about the efficacy of preventive long-term colchicine intake, methotrexate, and hydroxychloroquine in chronic CPPD. Needle aspiration and lavage have satisfactory short and midterm results in BCP. Extracorporeal shockwave therapy has also proved its efficacy for high-doses regimes. Phlebotomy does not seem to have shown real efficacy on joint involvement in HH so far. Iron chelators' effects have not been assessed on joint involvement either, while IL-1 blockade may prove useful. NSAIDs have limited efficacy on joint involvement of oxalosis, while colchicine and steroids have not been assessed either. The use of nitisinone for ochronotic arthropathy is still much debated, but it could provide beneficial effects on joint involvement. The effects of copper chelators have not been assessed either in the joint involvement of Wilson's disease. NSAIDs should be avoided because of the liver affection they may worsen.
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38
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Mistry JB, Bukhari M, Taylor AM. Alkaptonuria. Rare Dis 2013; 1:e27475. [PMID: 25003018 DOI: 10.4161/rdis.27475] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 12/15/2022] Open
Abstract
Alkaptonuria (AKU) is a rare disorder of autosomal recessive inheritance. It is caused by a mutation in a gene that results in the accumulation of homogentisic acid (HGA). Characteristically, the excess HGA means sufferers pass dark urine, which upon standing turns black. This is a feature present from birth. Over time patients develop other manifestations of AKU, due to deposition of HGA in collagenous tissues, namely ochronosis and ochronotic osteoarthropathy. Although this condition does not reduce life expectancy, it significantly affects quality of life. The natural history of this condition is becoming better understood, despite gaps in knowledge. Clinical assessment of the condition has also improved along with the development of a potentially disease-modifying therapy. Furthermore, recent developments in AKU research have led to new understanding of the disease, and further study of the AKU arthropathy has the potential to influence therapy in the management of osteoarthritis.
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Affiliation(s)
- Jemma B Mistry
- Lancaster Medical School; Faculty of Health & Medicine; Lancaster, UK
| | - Marwan Bukhari
- University Hospitals of Morecambe Bay NHS Foundation Trust; Royal Lancaster Infirmary; Lancaster, UK
| | - Adam M Taylor
- Lancaster Medical School; Faculty of Health & Medicine; Lancaster, UK
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Preston AJ, Keenan CM, Sutherland H, Wilson PJ, Wlodarski B, Taylor AM, Williams DP, Ranganath LR, Gallagher JA, Jarvis JC. Ochronotic osteoarthropathy in a mouse model of alkaptonuria, and its inhibition by nitisinone. Ann Rheum Dis 2013; 73:284-9. [PMID: 23511227 DOI: 10.1136/annrheumdis-2012-202878] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Alkaptonuria (AKU) is a rare metabolic disease caused by deficiency of homogentisate 1,2 dioxygenase, an enzyme involved in tyrosine catabolism, resulting in increased circulating homogentisic acid (HGA). Over time HGA is progressively deposited as a polymer (termed ochronotic pigment) in collagenous tissues, especially the cartilages of weight bearing joints, leading to severe joint disease. OBJECTIVES To characterise blood biochemistry and arthropathy in the AKU mouse model (Hgd-/-). To examine the therapeutic effect of long-term treatment with nitisinone, a potent inhibitor of the enzyme that produces HGA. METHODS Lifetime levels of plasma HGA from AKU mice were measured by high-performance liquid chromatography (HPLC). Histological sections of the knee joint were examined for pigmentation. The effect of nitisinone treatment in both tissues was examined. RESULTS Mean (±SE) plasma HGA levels were 3- to 4-fold higher (0.148±0.019 mM) than those recorded in human AKU. Chondrocyte pigmentation within the articular cartilage was first observed at 15 weeks, and found to increase steadily with mouse age. Nitisinone treatment reduced plasma HGA in AKU mice throughout their lifetime, and completely prevented pigment deposition. CONCLUSIONS The AKU mouse was established as a model of both the plasma biochemistry of AKU and its associated arthropathy. Early-stage treatment of AKU patients with nitisinone could prevent the development of associated joint arthropathies. The cellular pathology of ochronosis in AKU mice is identical to that observed in early human ochronosis and thus is a model in which the early stages of joint pathology can be studied and novel interventions evaluated.
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Affiliation(s)
- Andrew J Preston
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, Bone and Joint Research Group, University of Liverpool, , Liverpool, UK
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Ranganath LR, Jarvis JC, Gallagher JA. Recent advances in management of alkaptonuria (invited review; best practice article). J Clin Pathol 2013; 66:367-73. [PMID: 23486607 DOI: 10.1136/jclinpath-2012-200877] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Alkaptonuria (AKU) is an autosomal recessive condition arising as a result of a genetic deficiency of the enzyme homogentisate 1,2 dioxygenase and characterised by accumulation of homogentisic acid (HGA). Oxidative conversion of HGA leads to production of a melanin-like polymer in a process termed ochronosis. The binding of ochronotic pigment to the connective tissues of the body leads to multisystem disorder dominated by premature severe spondylo-arthropathy. Other systemic features include stones (renal, prostatic, salivary, gall bladder), renal damage/failure, osteopenia/fractures, ruptures of tendons/muscle/ligaments, respiratory compromise, hearing loss and aortic valve disease. Detection of these features requires systematic investigation. Treatment in AKU patients is palliative and unsatisfactory. Ascorbic acid, low protein diet and physiotherapy have been tried but do not alter the underlying metabolic defect. Regular surveillance to detect and treat complications early is important. Palliative pain management is a crucial issue in AKU. Timely spinal surgery and arthroplasty are the major treatment approaches at present. A potential disease modifying drug, nitisinone, inhibits 4-hydroxy-phenyl-pyruvate-dioxygenase and decreases formation of HGA and could prevent or slow the progression of disease in AKU. If nitisinone therapy is able to complement the biochemical 'cure' with improved outcomes, it will completely alter the way we approach the management of this disease. Greater efforts to improve recognition and registration of the disease will be worthwhile. Improved laboratory diagnostics to monitor the tyrosine metabolic pathway that includes plasma metabolites including tyrosine to monitor efficacy, toxicity and safety postnitisinone will also be required.
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Affiliation(s)
- Lakshminarayan R Ranganath
- Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital, Liverpool, UK.
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