RESUMEN
Introduction: Homocysteine (Hcy) tissue accumulation occurs in a metabolic disease characterized biochemically by cystathionine ß-synthase (CBS) deficiency and clinically by mental retardation, vascular problems, and skeletal abnormalities. Previous studies indicate the occurrence of DNA damage secondary to hyperhomocysteinemia and it was observed that DNA damage occurs in leukocytes from CBS-deficient patients. This study aimed to investigate whether an oxidative mechanism could be involved in DNA damage previously found and investigated the in vitro effect of N-acety-L-cysteine (NAC) on DNA damage caused by high Hcy levels. Methods: We evaluated a biomarker of oxidative DNA damage in the urine of CBSdeficient patients, as well as the in vitro effect of NAC on DNA damage caused by high levels of Hcy. Moreover, a biomarker of lipid oxidative damage was also measured in urine of CBS deficient patients. Results: There was an increase in parameters of DNA (8-oxo-7,8-dihydro-2'- deoxyguanosine) and lipid (15-F2t-isoprostanes levels) oxidative damage in CBS-deficient patients when compared to controls. In addition, a significant positive correlation was found between 15-F2t-isoprostanes levels and total Hcy concentrations. Besides, an in vitro protective effect of NAC at concentrations of 1 and 5 mM was observed on DNA damage caused by Hcy 50 µM and 200 µM. Additionally, we showed a decrease in sulfhydryl content in plasma from CBS-deficient patients when compared to controls. Discussion: These results demonstrated that DNA damage occurs by an oxidative mechanism in CBS deficiency together with lipid oxidative damage, highlighting the NAC beneficial action upon DNA oxidative process, contributing with a new treatment perspective of the patients affected by classic homocystinuria.
Asunto(s)
Humanos , Femenino , Niño , Adolescente , Adulto , Adulto Joven , Acetilcisteína/farmacología , Daño del ADN , Estrés Oxidativo , Cistationina/metabolismo , Desoxiguanosina/orina , Homocistinuria/genética , Antioxidantes/farmacología , Biomarcadores/orina , Estudios de Casos y Controles , Creatinina/orina , Ensayo Cometa , Cistationina/biosíntesis , Cistationina/sangre , Isoprostanos/análisis , Desoxiguanosina/análogos & derivados , Homocisteína/sangre , Homocistinuria/sangreRESUMEN
BACKGROUND: We describe body composition, lipid metabolism and Stearoyl-CoA desaturase-1 (SCD-1) indices in patients with classical homocystinuria (HCU). METHODS: Eleven treated HCU patients and 16 healthy controls were included. Body composition and bone mineral density were assessed by dual X-ray absorptiometry. Sulfur amino acids (SAA) and their derivatives (total homocysteine, cysteine, methionine, S-adenosylmethionine, S-adenosylhomocysteine, and glutathione), lipids (free fatty acids, acylcarnitines, triglycerides and lipoproteins), glucose, insulin, leptin, adiponectin, and isoprostanes were measured in plasma. Insulin resistance was evaluated by HOMA-IR. To estimate liver SCD-1 activity, SCD-16 [16:1(n-7)/16:0] and SCD-18 [18:1(n-9)/18:0] desaturation indices were determined. RESULTS: In HCU patients, SCD-16 index was significantly reduced (p=0.03). A trend of an association of SCD-16 index with cysteine was observed (r=0.624, p=0.054). HCU patients displayed lower lean mass (p<0.05), with no differences in fat mass percentage. Leptin and low-density lipoprotein concentrations were lower in HCU patients (p<0.05). Femur bone mineral density Z-scores were correlated with plasma cysteine (r=0.829; p=0.04) and total homocysteine (r=-0.829; p=0.04) in HCU patients. CONCLUSIONS: We report alterations in leptin and SCD-1 in HCU patients. These results agree with previous findings from epidemiologic and animal studies, and support a role for SAA on lipid homeostasis.
Asunto(s)
Aminoácidos Sulfúricos/sangre , Homocistinuria/sangre , Leptina/sangre , Metabolismo de los Lípidos , Estearoil-CoA Desaturasa/sangre , Adulto , Densidad Ósea , Femenino , Homocistinuria/metabolismo , Homocistinuria/fisiopatología , Humanos , Masculino , Adulto JovenRESUMEN
The role of the phase angle in hyperhomocysteinemia has yet to be assessed. Classical homocystinuria is a rare genetic disease characterized by severe hyperhomocysteinemia, as well as increased levels of methionine and reduced levels of cysteine. The objective of this study was to investigate the potential relationship between phase angle and homocysteine, cysteine, and methionine levels in patients with classical homocystinuria. Eight patients were included in the study. Phase angle was measured with a tetrapolar bioimpedance analyzer. Serum homocysteine, cysteine, and methionine levels were measured by HPLC. Only three patients had adequate metabolic control of their disease. Median phase angle was 5.9° (range = 5.4°-8.5°). There was a significant correlation between phase angle and levels of homocysteine (r = -0.807, p = 0.015), methionine (r = -0.711, p = 0.048), and cysteine (r = 0.836, p = 0.010). Was also positively correlated with BMI and arm muscle circumference (p < 0.05). Two patients had phase angles below the 5th percentile, and only one above the 50th percentile. Our findings suggest that cellular integrity is affected in patients with high homocysteine levels, thus indicating that phase angle could be a valuable indicator of prognosis and classical homocystinuria. It also suggests a role for this indicator in other forms of hyperhomocysteinemia and other inborn errors of metabolism.
Asunto(s)
Homocistinuria/sangre , Homocistinuria/diagnóstico , Hiperhomocisteinemia/sangre , Esperanza de Vida , Adolescente , Adulto , Cisteína/sangre , Femenino , Homocisteína/sangre , Humanos , Masculino , Metionina/sangre , Pronóstico , Adulto JovenRESUMEN
Homocystinuria is an inherited disorder biochemically characterized by high urinary excretion of homocystine and increased levels of homocysteine (Hcy) and methionine in biological fluids. Affected patients usually have a variety of clinical and pathologic manifestations. Previous experimental data have shown a relationship between Hcy and oxidative stress, although very little was reported on this process in patients with homocystinuria. Therefore, in the present study we evaluated parameters of oxidative stress, namely carbonyl formation, malondialdehyde (MDA) levels, sulfhydryl content and total antioxidant status (TAS) in patients with homocystinuria at diagnosis and under treatment with a protein restricted diet supplemented by pyridoxine, folate, betaine, and vitamin B(12). We also correlated plasma Hcy and methionine concentrations with the oxidative stress parameters examined. We found a significant increase of MDA levels and carbonyl formation, as well as a reduction of sulfhydryl groups and TAS in plasma of homocystinuric patients at diagnosis relatively to healthy individuals (controls). We also verified that Hcy levels were negatively correlated with sulfhydryl content and positively with MDA levels. Furthermore, patients under treatment presented a significant reduction of the content of MDA, Hcy and methionine concentrations relatively to patients at diagnosis. Taken together, the present data indicate that lipid and protein oxidative damages are increased and the antioxidant defenses diminished in plasma of homocystinuric patients, probably due to increased reactive species elicited by Hcy. It is therefore presumed that oxidative stress participates at least in part in the pathogenesis of homocystinuria.
Asunto(s)
Homocisteína/sangre , Homocistinuria/sangre , Homocistinuria/patología , Estrés Oxidativo , Adolescente , Adulto , Antioxidantes/metabolismo , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Humanos , Masculino , Malondialdehído/sangre , Carbonilación Proteica , Compuestos de Sulfhidrilo/sangre , Adulto JovenRESUMEN
BACKGROUND: Cystathionine beta-synthase (CBS) deficiency is the most common cause of homocystinuria. However, no data are available concerning the molecular basis of this disease in Brazilian populations. METHODS: We studied 14 Brazilian patients from 11 unrelated families using a combined screening approach, involving restriction analysis, single-strand conformational polymorphism (SSCP) scanning, and sequencing. RESULTS: All patients presented homocysteine levels higher than 200 mumol/l before the beginning of treatment. The most common CBS gene mutations, p.G307S (c.919G > A) and p.I278T (c.833T > C), were evaluated and the allele c.919A was not found. One allele with the c.844 ins68 (4.5%) in the CBS gene was found. Three families (6 patients) presented the allele c.833 C (13.6%), without the insertion in the heterozygous state. SSCP scanning and sequencing showed 3 alleles p.T191M (13.64%) in 2 families. One allele with a novel mutation was found in exon 4 (c.168T > A) of the CBS gene (4.5%). We also analyzed c.677C > T and c.1298A > C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the 2756A > G polymorphism in the methionine synthase (MTR) gene. The frequencies of mutated alleles were: 50% c.677T and 18.2% c.1298C for MTHFR, and 27.3% c.2756G for MTR. CONCLUSION: In spite of the high level of racial mixing in the country, Brazilian homocystinuric patients did not present a high prevalence of the most common mutations described in the literature.
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Homocistinuria/sangre , Homocistinuria/genética , 5-Metiltetrahidrofolato-Homocisteína S-Metiltransferasa/genética , Adolescente , Adulto , Alelos , Brasil , Niño , Preescolar , Cistationina betasintasa/deficiencia , Cistationina betasintasa/genética , Exones/genética , Femenino , Homocisteína/sangre , Homocistinuria/enzimología , Humanos , Masculino , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Mutación/genética , Polimorfismo Conformacional Retorcido-SimpleRESUMEN
In the present study we investigate the effect of homocysteine (Hcy) administration, the main metabolite accumulating in homocystinuria, on butyrylcholinesterase (BuChE) activity in serum of rats. For the acute treatment, 29-day-old Wistar rats received one subcutaneous injection of Hcy (0.6 micromol/g) or saline (control) and were killed 1 h later. For the chronic treatment, Hcy was administered subcutaneously to rats from the 6th to the 28th day of life. Control rats received saline. The rats were killed 12 h after the last injection. In another set of experiments, rats were pretreated for one week with vitamins E and C or saline and 12 h after the last injection received one single injection of Hcy or saline, being killed 1 h later. Serum was used to determine BuChE activity. Our results showed that acute and chronic administration of Hcy significantly decreased BuChE activity. Furthermore, vitamins E and C per se did not alter BuChE activity, but prevented the reduction of this enzyme activity caused by acute administration of Hcy. The data suggest that the inhibitory effect of Hcy on BuChE activity is probably mediated by free radicals, since vitamins E and C administration prevented such effect.
Asunto(s)
Butirilcolinesterasa/sangre , Regulación hacia Abajo/efectos de los fármacos , Homocistinuria/enzimología , Hiperhomocisteinemia/enzimología , Animales , Antioxidantes/metabolismo , Antioxidantes/farmacología , Arteriosclerosis/enzimología , Arteriosclerosis/fisiopatología , Ácido Ascórbico/metabolismo , Ácido Ascórbico/farmacología , Modelos Animales de Enfermedad , Regulación hacia Abajo/fisiología , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Radicales Libres/antagonistas & inhibidores , Radicales Libres/metabolismo , Homocisteína/metabolismo , Homocisteína/farmacología , Homocistinuria/sangre , Homocistinuria/tratamiento farmacológico , Hiperhomocisteinemia/sangre , Hiperhomocisteinemia/tratamiento farmacológico , Metabolismo de los Lípidos , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Ratas , Ratas Wistar , Vitamina E/metabolismo , Vitamina E/farmacologíaAsunto(s)
Enfermedades Cardiovasculares/epidemiología , Endotelio Vascular/fisiopatología , Homocisteína/sangre , Errores Innatos del Metabolismo de los Aminoácidos/sangre , Errores Innatos del Metabolismo de los Aminoácidos/genética , Errores Innatos del Metabolismo de los Aminoácidos/fisiopatología , Avitaminosis/complicaciones , Enfermedades Cardiovasculares/sangre , Trastornos Cerebrovasculares/sangre , Trastornos Cerebrovasculares/etiología , Homocisteína/metabolismo , Homocistinuria/sangre , Homocistinuria/complicaciones , Homocigoto , Humanos , Metionina/metabolismo , Isquemia Miocárdica/epidemiología , Isquemia Miocárdica/etiología , Enfermedades Vasculares Periféricas/sangre , Enfermedades Vasculares Periféricas/etiología , Factores de Riesgo , Tromboflebitis/sangre , Tromboflebitis/etiología , Vitaminas/uso terapéuticoRESUMEN
The aim of this study was to investigate the blood coagulation changes in three patients with homocystinuria, in baseline condition and during therapy. At baseline, antithrombin III activity and factor VII levels were reduced in all three patients; antithrombin III protein and protein C antigen were also slightly lowered in one patient, and factor X in another. beta-Thromboglobulin, a measure of platelet activation, was increased in one case. During pyridoxine treatment, antithrombin III activity was rapidly restored to normal; factor VII increased and beta-thromboglobulin decreased. These data suggest that, in addition to platelet activation, abnormalities of blood clotting, and particularly reduction of antithrombin III, may play a role in the thrombotic tendency associated with homocystinuria. The nature of these clotting alterations is still uncertain, but their improvement during active metabolic treatment suggests that the defect in amino acid transsulfuration of homocystinuria may directly affect synthesis or activity of some liver-dependent clotting factors.