RESUMEN
OBJECTIVES: Restless legs syndrome (RLS) is a common neurological condition. Oxidative stress plays an important role in its pathogenesis. Thiol-disulphide homeostasis (TDH) is a new biomarker of oxidative stress. We studied plasma TDH to determine whether TDH could be used as a new biomarker for RLS and evaluated correlations between TDH and various disease severity rating scales. METHODS: A total of 25 RLS patients and 25 healthy controls were included into the study. TDH status was determined using an automated spectrophotometric analysis method and correlations were analyzed between the TDH status and various disease rating scales in the RLS patients. RESULTS: Plasma total (401±27 µmol/L) and native thiol (354±30 µmol/L) levels were significantly lower, but disulphide level (24±6 µmol/L) was significantly (<0.0001) higher in the RLS patients compared to the controls (455±36, 424±37, 15±5 µmol/L, respectively). The disulphide/native thiol and disulphide/total thiol ratios increased, in contrast, native thiol/total thiol ratio decreased significantly in the RLS patients compared to the healthy controls (<0.0001). The disulphide levels correlated positively with age and various rating scores of the RLS patients. International Restless Legs Syndrome Study Group (IRLSSG) rating score and age correlated negatively with the total and native thiol levels. CONCLUSIONS: Our findings indicate increased oxidative stress in the RLS patients reflected by decreased native and total thiol, and increased disulphide levels and positive correlations between the disulphide levels and various rating scores. We suggest dynamic TDH status to be used as a novel biomarker for the diagnosis and follow-up of the RLS patients.
Asunto(s)
Disulfuros , Síndrome de las Piernas Inquietas , Biomarcadores , Estudios de Casos y Controles , Homeostasis , Humanos , Estrés Oxidativo , Compuestos de SulfhidriloRESUMEN
Restless legs syndrome (RLS) is a common sensorimotor disorder that, in case of severe symptoms, can be very distressing and negatively interfere with quality of life. Moreover, increasing evidences associate RLS with higher risk of cerebrovascular and cardiovascular disease (CVD). The purpose of this study was to quantify two proteins, previously identified by proteomics and potentially linked with CVD risk, namely kininogen-1 (KNG1) and alpha-1-antitrypsin (A1AT), in primary RLS patients at high severity grade (HS-RLS) in comparison to healthy control subjects. Proteins were quantified through enzyme-linked immunosorbent assay (ELISA) in plasma samples from 14 HS-RLS patients and 15 control individuals. The two groups were closely matched for age and gender. The expression level of KNG1 resulted significantly higher (p < 0.001), while A1AT was significantly decreased (p < 0.05) in HS-RLS patients compared to controls, confirming the relationship between these proteins and the disease severity. Furthermore, in patients group the association between the protein concentrations and the following parameters was further evaluated: age, disease onset and diagnosis, scores obtained from the RLS rating scales (Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Beck Depression Inventory) and smoking habit. All the considered variables resulted independent of protein levels, so the disease can be reasonably considered the main cause of protein changes. As emerged from the literature, high levels of KNG1 and low amounts of A1AT seem to be related with a highest probability to develop CVD. Consequently, these proteins may be reliable candidate biomarkers of CVD risk in patients with RLS at high severity grade.
Asunto(s)
Enfermedades Cardiovasculares/sangre , Quininógenos/sangre , Síndrome de las Piernas Inquietas/sangre , Índice de Severidad de la Enfermedad , alfa 1-Antitripsina/sangre , Adulto , Biomarcadores/sangre , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Síndrome de las Piernas Inquietas/diagnóstico , Síndrome de las Piernas Inquietas/epidemiología , Factores de RiesgoRESUMEN
OBJECTIVES: Restless legs syndrome (RLS) can lead to severe clinical consequences, thus negatively impacts on patients' overall health and quality of life. Nevertheless, the pathophysiology of RLS is still unclear, resulting in underestimate, incorrect, or ignored diagnosis and in limited management and treatment. The aim of this study was to compare the plasma proteome of RLS patients and healthy controls, in the search of diagnostic biomarkers related to the disease severity. MATERIALS AND METHODS: Two-dimensional gel electrophoresis coupled with liquid chromatography-mass spectrometry was employed to analyze plasma samples of 34 patients with primary RLS, divided into two subgroups according to the disease severity: MMS group (mild-moderate symptoms) and HS group (severe and very severe symptoms), and 17 age- and sex-matched control subjects. Sleep quality, daytime sleepiness, and the level of depression were also evaluated. RESULTS: We identified eight upregulated spots, corresponding to five unique proteins, in both RLS group vs. controls (alpha-1B-glycoprotein, alpha-1-acid glycoprotein 1, haptoglobin, complement C4-A, and immunoglobulin kappa constant); five increased spots, consistent with three unique proteins, only in HS-RLS (kininogen-1, immunoglobulin heavy constant alpha 1, and immunoglobulin lambda constant 2); one downregulated spot in both patient's groups (complement C3) and another one only in HS-RLS (alpha-1-antitrypsin). CONCLUSIONS: The significantly different plasma proteins detected in RLS were mainly associated with inflammation, immune response, and cardiovascular disorders. Particularly, the gradual increasing in immunoglobulins could be indicative of the disease severity and evolution. Accordingly, these proteins may represent a valid set of useful biomarkers for RLS diagnosis, progression and treatment.