ascorbic-acid and Alkaptonuria

Alkaptonuria is a disease often forgotten because of its rarity. Its pathogenic mechanism is the deficiency of one of the enzymes of the tyrosine degradation pathway-homogentisate-1, 2-dioxygenase, which sequelae is accumulation and deposition of its metabolite homogentisic acid in connective tissues and urine. Alkaptonuria presents as a clinical triad-darkening urine upon prolonged exposure to air, pigmentation of connective tissues and debilitating arthropathy. We present a case report of a 67-year old patient with alkaptonuria who presented with the clinical triad, but was mistakenly diagnosed as having ankylosing spondylitis in the past. Currently there is no treatment for the disease hence the management strategy was focused on symptoms control with analgesics, physical therapy, dietary modification, vitamin C supplementation, and joint arthroplasty. Alkaptonuria's clinical features are extensively described in the literature and despite the fact that it is a rare disease, due to the similar radiographic changes with spondyloarthropathies, it should be included in the differential diagnosis in young patients presenting with severe joint involvement. Early recognition of the disease is necessary since its natural evolution is joint destruction leading to significant reduction in the quality of life. Alkaptonuria's articular features in the spine and peripheral tissues are well described using the classical imaging techniques. Musculoskeletal ultrasonography shows a characteristic set of findings in the soft tissues, including synovium, cartilage, tendons and entheses.

Topics: Aged; Alkaptonuria; Ascorbic Acid; Cartilage Diseases; Dioxygenases; Homogentisic Acid; Humans; Joint Diseases; Ochronosis; Osteoarthritis; Quality of Life; Spondylarthropathies; Tyrosine

Alkaptonuria is a rare autosomal recessive metabolic disease that leads to the deposition of homogentisic acid. Ochronotic arthropathy is the articular manifestation of alkaptonuria with the most common clinical feature being severe spondyloarthropathy. We present the case of a 58-year-old woman with back pain. Radiographs and magnetic resonance imaging (MRI) revealed characteristic features of ochronotic spondyloarthropathy. The literature regarding management of alkaptonuria is reviewed.

Topics: Alkaptonuria; Antioxidants; Ascorbic Acid; Female; Homogentisate 1,2-Dioxygenase; Homogentisic Acid; Humans; Low Back Pain; Middle Aged; Ochronosis; Spondylarthropathies

A 50-year-old man presented with a complaint of low-back pain and widespread joint pain for the previous 20 years. Conventional radiography revealed wide areas of calcification in the intervertebral discs and degenerative changes in the peripheral joints. A diagnosis of ochronosis was made by the observation of bluish-brown pigmentation in the nose and ears, dark urine colors following alkalization, and high levels of homogentisic acid in the urine. Ochronosis should be considered in the differential diagnosis of patients with chronic low-back pain regarding features of widespread calcification in the intervertebral discs at radiography and bluish-brown pigmentation in the nose and ears.

Topics: Alkaptonuria; Anti-Inflammatory Agents, Non-Steroidal; Arthralgia; Ascorbic Acid; Back Pain; Calcinosis; Chronic Disease; Diagnosis, Differential; Diclofenac; Homogentisic Acid; Humans; Intervertebral Disc; Male; Middle Aged; Ochronosis; Radiography; Treatment Outcome; Vitamins

Topics: Alkaptonuria; Animals; Ascorbic Acid; Disease Models, Animal; History, 19th Century; History, 20th Century; Humans; United Kingdom

Topics: Alkaptonuria; Ascorbic Acid; Cartilage, Articular; Homogentisic Acid; Humans; Joint Diseases; Ochronosis; Oxygenases; Tyrosine

Alkaptonuria is a rare genetic disorder resulting in abnormality of tyrosine metabolism. It is one of the Garrod's tetrad of 'inborn errors of metabolism' proposed to have Mendelian recessive inheritance. The disorder is characterised by deposition of homogentisic acid leading to ochronosis and ochronotic osteoarthropathy; however, blackish discoloration of urine is the only childhood manifestation. Other manifestations present only after third decade. A 13-year-old boy presented to paediatric nephrology clinic with blackish discolouration of urine since infancy. Examination revealed bluish black discolouration of bilateral sclera and ear cartilage; however, he had no symptoms of ochronotic osteoarthropathy. Genetic test pointed towards alkaptonuria. Currently, he is on regular follow-up and is being treated with vitamin C to delay the progression of the disease. Early diagnosis with appropriate intervention delays the onset of complications and preserves the quality of life of the patient.

Topics: Adolescent; Alkaptonuria; Antioxidants; Ascorbic Acid; Disease Progression; Early Diagnosis; Humans; Male; Ochronosis; Sclera

Alkaptonuria (AKU) is an ultra-rare autosomal recessive disease that currently lacks an appropriate therapy. Recently we provided experimental evidence that AKU is a secondary serum amyloid A (SAA)-based amyloidosis. The aim of the present work was to evaluate the use of antioxidants to inhibit SAA amyloid and pro-inflammatory cytokine release in AKU.. We adopted a human chondrocytic cell AKU model to evaluate the anti-amyloid capacity of a set of antioxidants that had previously been shown to counteract ochronosis in a serum AKU model. Amyloid presence was evaluated by Congo red staining. Homogentisic acid-induced SAA production and pro-inflammatory cytokine release (overexpressed in AKU patients) were evaluated by ELISA and multiplex systems, respectively. Lipid peroxidation was evaluated by means of a fluorescence-based assay.. Our AKU model allowed us to prove the efficacy of ascorbic acid combined with N-acetylcysteine, taurine, phytic acid and lipoic acid in significantly inhibiting SAA production, pro-inflammatory cytokine release and membrane lipid peroxidation.. All the tested antioxidant compounds were able to reduce the production of amyloid and may be the basis for establishing new therapies for AKU amyloidosis.

Topics: Acetylcysteine; Alkaptonuria; Antioxidants; Ascorbic Acid; Cell Line; Chondrocytes; Cytokines; Humans; Inflammation; Lipid Peroxidation; Phytic Acid; Serum Amyloid A Protein; Taurine; Thioctic Acid

Alkaptonuria (AKU) is a rare genetic disease associated with deficient homogentisate 1,2-dioxygenase activity in the liver. This leads to the accumulation of homogentisic acid (HGA) and its oxidized/polymerized products in connective tissues, which in turn become characterized by the presence of melanin-like pigments (ochronosis). Since at present, further studies are necessary to support the use of drugs for the treatment of AKU, we investigated the effects of various anti-oxidants in counteracting melanin-like pigmentation and oxidative stress related to HGA and its metabolites.. We set up an in vitro model using human serum treated with 0.33 mM HGA and tested the anti-oxidants ascorbic acid, N-acetylcysteine, phytic acid (PHY), taurine (TAU), ferulic acid (FER) and lipoic acid (LIP) for their ability to prevent or delay the production of melanin-like pigments, as well as to reduce oxidative post-translational modifications of proteins. Monitoring of intrinsic fluorescence of HGA-induced melanin-like pigments was used to evaluate the efficacy of compounds.. Our model allowed us to prove efficacy especially for PHY, TAU, LIP and FER in counteracting the production of HGA-induced melanin-like pigments and protein oxidation induced by HGA and its metabolites.. Our model allows the opening of new anti-oxidant therapeutic strategies to treat alkaptonuric ochronosis.

Topics: Acetylcysteine; Alkaptonuria; Antioxidants; Ascorbic Acid; Cells, Cultured; Coumaric Acids; Homogentisic Acid; Humans; Ochronosis; Oxidative Stress; Phytic Acid; Protein Carbonylation; Taurine; Thioctic Acid

Alkaptonuria (AKU) is a rare autosomal recessive disease, associated with deficiency of homogentisate 1,2-dioxygenase activity in the liver. This leads to an accumulation of homogentisic acid (HGA) and its oxidized derivatives in polymerized form in connective tissues especially in joints. Currently, AKU lacks an appropriate therapy. Hence, we propose a new treatment for AKU using the antioxidant N-acetylcysteine (NAC) administered in combinations with ascorbic acid (ASC) since it has been proven that NAC counteracts the side-effects of ASC. We established an in vitro cell model using human articular primary chondrocytes challenged with an excess of HGA (0.33 mM). We used this experimental model to undertake pre-clinical testing of potential antioxidative therapies for AKU, evaluating apoptosis, viability, proliferation, and metabolism of chondrocytes exposed to HGA and treated with NAC and ASC administered alone or in combination addition of both. NAC decreased apoptosis induced in chondrocytes by HGA, increased chondrocyte growth reduced by HGA, and partially restored proteoglycan release inhibited by HGA. A significantly improvement in efficacy was found with combined addition of the two antioxidants in comparison with NAC and ASC alone. Our novel in vitro AKU model allowed us to demonstrate the efficacy of the co-administration of NAC and ASC to counteract the negative effects of HGA for the treatment of ochronotic arthropathy.

Topics: Acetylcysteine; Alkaptonuria; Antioxidants; Apoptosis; Ascorbic Acid; Cartilage, Articular; Cell Proliferation; Cell Survival; Cells, Cultured; Chondrocytes; Homogentisate 1,2-Dioxygenase; Homogentisic Acid; Humans; Ochronosis; Protein Carbonylation

A 38 years old man presented with 2 years history of low backache and progressively increasing stiffness of the spine. Movements were restricted at lumbar spine due to stiffness especially forward flexion was markedly reduced. He was suspected to be suffering from ankylosing spondylitis. There was no tenderness over sacroiliac joints or lumbar spine. Yellowish green Ochronotic pigmentation of cartilage of ears was noted. Radiographs of lumbar and thoracic spine revealed narrowing of inter-vertebral spaces with calcification of intervertebral discs. Homogentisic acid was present in the patient's urine sample, suggesting him to be suffering from Alkaptonuria. Patient is being managed with non steroidal anti-inflammatory drugs and vitamin C, 1g daily.

Topics: Adult; Alkaptonuria; Anti-Inflammatory Agents, Non-Steroidal; Ascorbic Acid; Homogentisic Acid; Humans; Intervertebral Disc; Low Back Pain; Male; Ochronosis; Radiography; Spondylitis, Ankylosing; Treatment Outcome; Vitamins

There is no definitive treatment protocol for alkaptonuria. A patient with alkaptonuria was treated with ascorbic acid (0.5 g/day) from the age of 4 years. He developed episodes of severe recurrent joint pain at 9.5 years of age after which a protein-restricted diet (1.3 g/kg/day) was started. Protein restriction in combination with ascorbic acid therapy (1 g/day in two divided doses) resulted in a significant decrease but not a normalization of the urinary homogentisic acid excretion. Joint pain resolved and the radiological evidence of 'moth-eaten' irregularities on the articular surface in both knees disappeared. He is currently well, growing normally and in nitrogen balance. Our findings document a reversal of bone abnormalities and clinical symptoms in a case of alkaptonuria. The results should be confirmed in a larger study. We suggest that protein restriction should be applied in combination with ascorbic acid in affected patients as soon as joint pain occurs.

Topics: Alkaptonuria; Ascorbic Acid; Child, Preschool; Humans; Knee; Magnetic Resonance Spectroscopy; Male; Radiography; Time Factors

Topics: 4-Hydroxyphenylpyruvate Dioxygenase; Alkaptonuria; Antioxidants; Ascorbic Acid; Benzoquinones; Cyclohexanones; Enzyme Inhibitors; Homogentisic Acid; Humans; Nitrobenzoates; Oxidation-Reduction

To detect and follow-up the metabolic status of patients with alkaptonuria (AKU), urinary homogentisic acid (HGA) was measured by gas chromatography. These results were close to values we obtained by colorimetric method (linearity: upto 700 mg/l, detection limit: 1 mg/l, within-run imprecision (CV): 1.2% at 100 mg/l HGA, 4.9% at 10 mg/l, between-run CV: 6.8% at 100 mg/l). To determine urinary reference ranges of HGA, 84 healthy children (age: 2 months-18 years) were divided into five age groups. HGA and creatinine were measured in their morning urine. Statistical analysis proved that urinary HGA/creatinine ratio is age-dependent. The ratio is relatively high between 1 and 6 years of age, with large scatter (upper limit of reference ranges given as mean + 2 SD: 5.5-7.2 mg/mmol = 0.03-0.04 mmol/mmol creatinine), and it decreases with age. Approximately at the age of 7 years, HGA/creatinine ratio becomes constant, and later it is similar to the adult value (upper limit: 2.8 mg/ mmol = 0.017 mmol/mmol creatinine). We monitored a patient during her 1-5th year of life, and her urinary HGA was 80-200 times higher than the upper limit of the age-matched reference ranges. The measurement of HGA supports the decision for starting restricted protein diet and is useful for the evaluation of the effectiveness of therapy.

Topics: Adolescent; Age Distribution; Alkaptonuria; Antioxidants; Ascorbic Acid; Case-Control Studies; Child; Child, Preschool; Chromatography, Gas; Colorimetry; Creatinine; Homogentisic Acid; Humans; Infant; Infant, Newborn

In a 3-year-old boy alkaptonuria was diagnosed. From early age on gradual dark discoloration of his urine had been noticed in the diapers, but routine urinalysis had not revealed abnormalities. Alkaptonuria is a rare metabolic disease in which homogentisic acid cannot be metabolised, due to a lack of the enzyme homogentisic acid oxidase. The disease often manifests itself in childhood by darkening of urine on standing. The excretion of homogentisic acid in urine in these patients is increased. The disease leads to serious consequences, such as ochronosis of cartilage and connective tissues with arthritis. It is expected that treatment with ascorbic acid and a dietary restriction of protein (1 g/kg/day) can decrease the late and serious consequences by diminishing the serum concentration of the metabolite benzoquinone acetic acid.

Topics: Alkaptonuria; Antioxidants; Ascorbic Acid; Child, Preschool; Diagnosis, Differential; Diet, Protein-Restricted; Homogentisic Acid; Humans; Male; Treatment Outcome

Topics: Alkaptonuria; Ascorbic Acid; Dietary Proteins; Humans; Male; Middle Aged

Topics: Adult; Alkaptonuria; Ascorbic Acid; Humans; Low Back Pain; Male; Treatment Outcome

Topics: Alkaptonuria; Ascorbic Acid; Child, Preschool; Chromatography, High Pressure Liquid; Creatinine; Female; Homogentisic Acid; Humans

Topics: Alkaptonuria; Animals; Ascorbic Acid; Dioxygenases; Homogentisate 1,2-Dioxygenase; Homogentisic Acid; Humans; Liver; Mice; Ochronosis; Oxygenases

The effects of ascorbic acid on the excretion of homogentisic acid and its derivative benzoquinone acetic acid were studied in two adults and three infants. The administration of relatively large amounts of ascorbic acid to the adults was followed by a disappearance of benzoquinone acetic acid from the urine, whereas the level of excretion of homogentisic acid did not change. This could have relevance to the pathogenesis of ochronotic arthritis. In the 4-mo-old infant and the 5-mo-old infant ascorbic acid in the urine may have doubled the amount of homogentisic acid, presumably through an effect on the immature p-hydroxyphenylpyruvic acid oxidase. Dietary reduction of the intake of tyrosine and phenylalanine substantially reduced the excretion of homogentisic acid.

Topics: Aged; Alkaptonuria; Ascorbic Acid; Benzoquinones; Homogentisic Acid; Humans; Infant; Male; Middle Aged; Quinones

The metabolic disorder, alkaptonuria, is distinguished by elevated serum levels of 2,5-dihydroxyphenylacetic acid (homogentisic acid), pigmentation of cartilage and connective tissue and, ultimately, the development of inflammatory arthritis. Oxygen radical generation during homogentisic acid autoxidation was characterized in vitro to assess the likelihood that oxygen radicals act as molecular agents of alkaptonuric arthritis in vivo. For homogentisic acid autoxidized at physiological pH and above, yielding superoxide (O2-)2 and hydrogen peroxide (H2O2), the homogentisic acid autoxidation rate was oxygen dependent, proportional to homogentisic acid concentration, temperature dependent and pH dependent. Formation of the oxidized product, benzoquinoneacetic acid was inhibited by the reducing agents, NADH, reduced glutathione, and ascorbic acid and accelerated by SOD and manganese-pyrophosphate. Manganese stimulated autoxidation was suppressed by diethylenetriaminepentaacetic acid (DTPA). Homogentisic acid autoxidation stimulated a rapid cooxidation of ascorbic acid at pH 7.45. Hydrogen peroxide was among the products of cooxidation. The combination of homogentisic acid and Fe3+-EDTA stimulated hydroxyl radical (OH.) formation estimated by salicylate hydroxylation. Ferric iron was required for the reaction and Fe3+-EDTA was a better catalyst than either free Fe3+ or Fe3+-DTPA. SOD accelerated OH. production by homogentisic acid as did H2O2, and catalase reversed much of the stimulation by SOD. Catalase alone, and the hydroxyl radical scavengers, thiourea and sodium formate, suppressed salicylate hydroxylation. Homogentisic acid and Fe3+-EDTA also stimulated the degradation of hyaluronic acid, the chief viscous element of synovial fluid. Hyaluronic acid depolymerization was time dependent and proportional to the homogentisic acid concentration up to 100 microM. The level of degradation observed was comparable to that obtained with ascorbic acid at equivalent concentrations. The hydroxyl radical was an active intermediate in depolymerization. Thus, catalase and the hydroxyl radical scavengers, thiourea and dimethyl sulfoxide, almost completely suppressed the depolymerization reaction. The ability of homogentisic acid to generate O2-, H2O2 and OH. through autoxidation and the degradation of hyaluronic acid by homogentisic acid-mediated by OH. production suggests that oxygen radicals play a significant role in the etiology of alkaptonuric arthritis.

Topics: Alkaptonuria; Animals; Arthritis; Ascorbic Acid; Edetic Acid; Free Radicals; Homogentisic Acid; Hyaluronic Acid; Oxidation-Reduction; Oxygen Consumption; Polarography; Pyrogallol; Superoxide Dismutase

Topics: Alkaptonuria; Ascorbic Acid; Homogentisic Acid; Humans; Hydrogen-Ion Concentration; Infant; Male; Pigmentation; Spectrophotometry

Topics: Adult; Alkaptonuria; Ascorbic Acid; Female; Humans; Male; Middle Aged

Homogentisic acid inhibits the in vitro activity of chick embryo lysyl hydroxylase, a microsomal enzyme which catalyzes the transformation of certain lysyl residues in collagen to hydroxylysine. Chick embryo lysyl hydroxylase activity was measured as specific tritium release as tritium water from a [4,5-(3)H]lysine-labeled unhydroxylated collagen substrate prepared from chick calvaria. Kinetic studies revealed a linear, noncompetitive type of inhibition with respect to collagen substrate with a Ki of 120-180 muM. The inhibition by homogentisic acid was reversible in that enzyme activity could be restored after dialysis of preincubated mixtures of homogentisic acid with enzyme or substrate. The inhibition by homogentisic acid was competitive with respect to ascorbic acid, and the addition of reducing agents, such as ascorbic acid or 1,4-dithiothreitol, protected lysyl hydroxylase activity from homogentisic acid inhibition.In organ cultures of embryonic chick calvaria, biosynthesis of hydroxylysine-derived intermolecular collagen cross-links was inhibited in a dose-dependent manner by 0.5-5 mM homogentisic acid. Because homogentisic acid inhibits the formation of hydroxylysine in a cell-free assay and in organ cultures, this compound must pass into the cells of calvaria to inhibit intracellular hydroxylysine formation and subsequently to diminish the reducible intermolecular cross-links of the newly synthesized collagen. We propose that the inhibition of lysyl hydroxylase and the resulting hydroxylsine-deficient, structurally modified collagen may be clinically significant in the defective connective tissue found in alkaptonuric patients.

Topics: Alkaptonuria; Animals; Ascorbic Acid; Chick Embryo; Collagen; Connective Tissue; Dithiothreitol; Homogentisic Acid; Kinetics; Mixed Function Oxygenases; Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase; Skull

Topics: Alkaptonuria; Ascorbic Acid; Chromatography, Thin Layer; Dihydroxyphenylalanine; Drug Stability; Gentisates; Homogentisic Acid; Humans; Male; Methods; Middle Aged; Phenylacetates; Spectrophotometry; Time Factors

Topics: Alkaptonuria; Ascorbic Acid; Diagnosis, Differential; Diet Therapy; Dietary Proteins; Humans; Joint Diseases; Male; Middle Aged; Ochronosis; Radiography

Topics: Alkaptonuria; Ascorbic Acid; Female; Humans; Infant

Topics: Adult; Alkaptonuria; Ascorbic Acid; Humans; Male; Methylthiouracil; Middle Aged; Osteoarthritis; Radiography; Salicylates

Topics: Alkaptonuria; Ascorbic Acid; Binding Sites; Carbon Isotopes; Connective Tissue; Disease Models, Animal; Ochronosis; Penicillamine; Phenylacetates; Sternum; Tendons; Tyrosine

Topics: Adult; Alkaptonuria; Ascorbic Acid; Diagnosis, Differential; Diagnostic Errors; Female; Glycosuria, Renal; Humans; Male; Middle Aged

Topics: Aged; Alkaptonuria; Ascorbic Acid; Diagnosis, Differential; Female; Femoral Neck Fractures; Humans; Methandrostenolone; Ochronosis; Osteoporosis; Phenylacetates; Polymyalgia Rheumatica; Radiography; Skull; Vitamin D

Topics: Adult; Alkaptonuria; Ascorbic Acid; Bone and Bones; Female; Humans; Methylthiouracil; Ochronosis; Physical Therapy Modalities; Radiography

Topics: Alkaptonuria; Ascorbic Acid; Bilirubin; Biphenyl Compounds; Clinical Laboratory Techniques; Cyanates; Enzymes; Epinephrine; Fructose; Glucose Oxidase; Glucose Tolerance Test; Glycosuria; Humans; Hydrazones; Hydroquinones; Indicators and Reagents; Iron; Jaundice; Melanins; Metabolic Diseases; Peroxidases; Phenylacetates; Silver Nitrate

Topics: Alkaptonuria; Amino Acids; Antifibrinolytic Agents; Ascorbic Acid; Thiouracil; Vitamins