One approach to interrupting the transmission of insect-borne diseases that is successfully used in veterinary medicine is exploiting the ability of antiparasitic drugs to make vertebrate blood toxic for blood-feeding insects. Recent studies have identified 4-hydroxyphenylpyruvate dioxygenase (HPPD), an enzyme of the tyrosine detoxification pathway, as essential for hematophagous arthropods to digest their blood meals. Such blood-feeding insects include anopheline mosquitoes, which transmit malaria-causing parasites.
View Article and Find Full Text PDFCommun Med (Lond)
February 2025
Background: Accurately recognizing that a person may be dying is central to improving their experience of care at the end-of-life. However, predicting dying is frequently inaccurate and often occurs only hours or a few days before death.
Methods: We performed urinary metabolomics analysis on patients with lung cancer to create a metabolite model to predict dying over the last 30 days of life.
Purpose: To report active and passive hip range of motion (ROM) data for individuals with alkaptonuria (AKU), with consideration for age, sex, and non-AKU comparative data.
Materials And Methods: Using a cross-sectional study design, 123 patients who had baseline ROM assessed in a previous international, multi-centre clinical trial were included. Data was compared between age groups, sexes, and with existing data from individuals without AKU.
Ochronotic pigmentation of connective tissue is the central pathological process in the rare metabolic disease alkaptonuria (AKU). Tissue pigmentation in AKU occurs due to unmetabolised homogentisic acid (HGA) in the circulation, caused by an enzyme deficiency in the liver. Ochronotic pigmentation, derived from HGA, has previously been reported and described in large joints obtained from arthroplasty surgeries, which typically have advanced disease.
View Article and Find Full Text PDFNat Rev Dis Primers
March 2024
Introduction: Paget's disease of bone (PDB) frequently presents at an advanced stage with irreversible skeletal damage. Clinical outcomes might be improved by earlier diagnosis and prophylactic treatment.
Methods: We randomised 222 individuals at increased risk of PDB because of pathogenic variants to receive 5 mg zoledronic acid (ZA) or placebo.
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).
View Article and Find Full Text PDFDespite urgent warnings about the spread of multidrug-resistant bacteria, the antibiotic development pipeline has remained sparsely populated. Naturally occurring antibacterial compounds may provide novel chemical starting points for antibiotic development programs and should be actively sought out. Evaluation of homogentisic acid (HGA), an intermediate in the tyrosine degradation pathway, showed that the compound had innate activity against Gram-positive and Gram-negative bacteria, which was lost following conversion into the degradation product benzoquinone acetic acid (BQA).
View Article and Find Full Text PDFAmongst a cohort of 88 alkaptonuria (AKU) patients attending the United Kingdom National Alkaptonuria Centre (NAC), four unrelated patients had co-existing Parkinson's disease (PD). Two of the NAC patients developed PD before receiving nitisinone (NIT) while the other two developed overt PD during NIT therapy. NIT lowers redox-active homogentisic acid (HGA) and profoundly increases tyrosine (TYR).
View Article and Find Full Text PDFJ Inherit Metab Dis
September 2023
Until now, only a few studies have focused on the early onset of symptoms of alkaptonuria (AKU) in the pediatric population. This prospective, longitudinal study is a comprehensive approach to the assessment of children with recognized AKU during childhood. The study includes data from 32 visits of 13 patients (five males, eight females; age 4-17 years) with AKU.
View Article and Find Full Text PDFEndocr Regul
January 2023
Alkaptonuria (AKU, OMIM, No. 203500) is a rare, slow-progressing, irreversible, multisystemic disease resulting from a deficiency of the homogentisate 1,2-dioxygenase enzyme, which leads to the accumulation of homogentisic acid (HGA) and subsequent deposition as pigment in connective tissues called ochronosis. As a result, severe arthropathy of large joints and spondyloarthropathy with frequent fractures, ligament ruptures, and osteoporosis develops in AKU patients.
View Article and Find Full Text PDFBackground: Familial combined hypolipidaemia is a condition characterised by very low concentrations of circulating very-low-density lipoprotein (VLDL), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL). It is thought that low LDL/combined hypolipidaemia can protect from cardiovascular disease (CVD), but this is not what we found in a case we present.
Objective: We report on a 57-years-old male patient with combined hypolipidaemia who presented with premature peripheral vascular disease.
Nitisinone (NTBC) was recently approved to treat alkaptonuria (AKU), but there is no information on its impact on oxidative stress and inflammation, which are observed in AKU. Therefore, serum samples collected during the clinical studies SONIA1 (40 AKU patients) and SONIA2 (138 AKU patients) were tested for Serum Amyloid A (SAA), CRP and IL-8 by ELISA; Advanced Oxidation Protein Products (AOPP) by spectrophotometry; and protein carbonyls by Western blot. Our results show that NTBC had no significant effects on the tested markers except for a slight but statistically significant effect for NTBC, but not for the combination of time and NTBC, on SAA levels in SONIA2 patients.
View Article and Find Full Text PDFAlkaptonuria (AKU) is a rare autosomal recessive disorder caused by mutations within a gene coding for homogentisate 1,2-dioxygenase (HGD). To date, 251 different variants of this gene have been reported. The metabolic disorder in AKU leads to the accumulation of homogentisic acid (HGA), resulting in ochronosis (pigmentation of the connective tissues) and severe ochronotic spondylo-arthropathy, which usually manifests in the mid-thirties.
View Article and Find Full Text PDFMetabolites
September 2022
Metabolomic analyses in alkaptonuria (AKU) have recently revealed alternative pathways in phenylalanine-tyrosine (phe-tyr) metabolism from biotransformation of homogentisic acid (HGA), the active molecule in this disease. The aim of this research was to study the phe-tyr metabolic pathway and whether the metabolites upstream of HGA, increased in nitisinone-treated patients, also undergo phase 1 and 2 biotransformation reactions. Metabolomic analyses were performed on serum and urine from patients partaking in the SONIA 2 phase 3 international randomised-controlled trial of nitisinone in AKU (EudraCT no.
View Article and Find Full Text PDFChanges in the phenylalanine (PHE)/tyrosine (TYR) pathway metabolites before and during homogentisic acid (HGA)-lowering by nitisinone in the Suitability of Nitisinone in Alkaptonuria (AKU) 2 (SONIA 2) study enabled the magnitude of the flux in the pathway to be examined. SONIA 2 was a 48-month randomised, open-label, evaluator-blinded, parallel-group study performed in the UK, France and Slovakia recruiting patients with confirmed AKU to receive either 10 mg nitisinone or no treatment. Site visits were performed at 3 months and yearly thereafter.
View Article and Find Full Text PDFObjectives: Ochronotic spondyloarthropathy represents one of the main clinical manifestations of alkaptonuria (AKU); however, prospective data and description of the effect of nitisinone treatment are lacking.
Methods: Patients with AKU aged 25 years or older were randomly assigned to receive either oral nitisinone 10 mg/day (N=69) or no treatment (N=69). Spine radiographs were recorded yearly at baseline, 12, 24, 36 and 48 months, and the images were scored for the presence of intervertebral space narrowing, soft tissue calcifications, vacuum phenomena, osteophytes/hyperostosis and spinal fusion in the cervical, thoracic and lumbosacral segment at each of the time points.
Nitisinone (NIT) causes tyrosinaemia and corneal keratopathy (KP), especially in men. However, the adaptation within the phenylalanine (PHE)/tyrosine (TYR) catabolic pathway during KP is not understood. The objective of this study is to assess potential differences in the PHE/TYR pathway during KP and the influence of gender in NIT-induced tyrosinaemia in alkaptonuria (AKU).
View Article and Find Full Text PDFAlkaptonuria (AKU) is a rare debilitating autosomal recessive disorder of tyrosine (TYR) metabolism which results in a deficiency of the enzyme homogentisate 1,2-dioxygenase activity. Several studies have reported the metabolic changes in homogentisic acid (HGA) concentrations and subsequent deposition of an ochronotic pigment in connective tissues, especially cartilage. Treatment with nitisinone (NTBC) reduces urinary and circulating HGA, but its mode of action results in hypertyrosinaemia.
View Article and Find Full Text PDFHomogentisic acid (HGA) lowering, disease modifying off-label nitisinone therapy has been used in the United Kingdom National Alkaptonuria Centre (NAC) since 2012. This study evaluated the serendipitous observation of cataract in a large cohort of patients with the very rare disease alkaptonuria (AKU), over a 5-year period. Patients with AKU who attended the NAC since 2012.
View Article and Find Full Text PDFAlkaptonuria (AKU) is a rare genetic disorder where oxidised homogentisic acid accumulates in connective tissues, leading to multisystem disease. The clinical evaluation Alkaptonuria Severity Score Index (cAKUSSI) is a composite score that assesses the extent of AKU disease. However, some components assess similar disease features, are difficult to measure reliably or cannot be measured in resource-limited environments.
View Article and Find Full Text PDFBackground: Nitisinone-induced hypertyrosinaemia is well documented in Alkaptonuria (AKU), and there is uncertainty over whether it may contribute to a decline in cognitive function and/or mood by altering neurotransmitter metabolism. The aim of this work was to evaluate the impact of nitisinone on the cerebrospinal fluid (CSF) metabolome in a murine model of AKU, with a view to providing additional insight into metabolic changes that occur following treatment with nitisinone. Methods: 17 CSF samples were collected from BALB/c Hgd−/− mice (n = 8, treated with nitisinone—4 mg/L and n = 9, no treatment).
View Article and Find Full Text PDFLittle is documented on whether nitisinone-induced hypertyrosinaemia alters cognitive functioning or leads to worsening depression in alkaptonuria (AKU). Wechsler Adult Intelligence Scale-IV (WAIS-IV) and Beck Depression Inventory-II (BDI-II) assessments were performed before and annually following treatment with nitisinone 2 mg daily to assess the impact on cognitive functioning and severity of depression. Serum tyrosine concentrations were also measured annually.
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