Copper is an essential metal for the function of many proteins related to important cellular reactions and also involved in the synaptic transmission. Although there are several mechanisms involved in copper homeostasis, a dysregulation in this process can result in serious neurological consequences, including degeneration of dopaminergic neurons. 6-Hydroxydopamine is a dopaminergic neurotoxin mainly used in experimental models of Parkinson's disease, whose neurotoxicity has been related to its ability to generate free radicals. In this study, we examined the effects induced by copper on 6-OHDA autoxidation. Our data show that both Cu and Cu caused an increase in OH production by 6-OHDA autoxidation, which was accompanied by an increase in the rate of both p-quinone formation and H O accumulation. The presence of ascorbate greatly enhanced this process by establishing a redox cycle which regenerates 6-OHDA from its p-quinone. However, the presence of glutathione did not change significantly the copper-induced effects. We observed that copper is able to potentiate the ability of 6-OHDA to cause both lipid peroxidation and protein oxidation, with the latter including a reduction in free-thiol content and an increase in carbonyl content. Ascorbate also increases the lipid peroxidation induced by the action of copper and 6-OHDA. Glutathione protects against the copper-induced lipid peroxidation, but does not reduce its potential to oxidize free thiols. These results clearly demonstrate the potential of copper to increase the capacity of 6-OHDA to generate oxidative stress and the ability of ascorbate to enhance this potential, which may contribute to the destruction of dopaminergic neurons.
Redox properties enable copper to perform its essential role in many biological processes, but they can also convert it into a potentially hazardous element. Its dyshomeostasis may have serious neurological consequences, and its possible involvement in Parkinson's disease and other neurodegenerative disorders has been suggested. The in vitro and ex vivo ability of copper to increase oxidative stress has already been demonstrated, and the aim of the present study was to assess in vivo the capacity of copper to cause brain oxidative damage and its ability to increase the dopaminergic degeneration induced by 6-hydroxydopamine. We found that chronic copper administration (10 mg Cu/kg/day, IP) causes its accumulation in different brain areas (cortex, striatum, nigra) and was accompanied by an increase in TBARS levels and a decrease in protein free-thiol content in the cortex. A decrease in catalase activity and an increase in glutathione peroxidase activity were also observed in the cortex. The intrastriatal administration of Cu caused an increase in some indices of oxidative stress (TBARS and protein free-thiol content) in striatum and nigra, but was unable to induce dopaminergic degeneration. However, when copper was intrastriatally coadministered with 6-hydroxydopamine, it increased dopaminergic degeneration, a fact that was also accompanied by an increase in the assayed indices of oxidative stress, a decrease in catalase activity, and an augmentation in glutathione activity. Evidently, copper cannot cause neurodegeneration per se, but may potentiate the action of other factors involved in the pathogenesis of Parkinson's disease through oxidative stress.
We aimed to explore the influence that the circadian blood pressure (BP) profile could exert on the correlation between some inflammatory markers and hypertension-mediated organ damage (HMOD). This was a cross-sectional study that included patients with primary arterial hypertension older than 18 years old. We included some parameters of 24 h ambulatory blood pressure monitoring collection and several inflammatory markers, as follows: platelet count (PTC), erythrocyte sedimentation rate (ESR), ultrasensitive C-reactive-protein, ferritin, fibrinogen, and uric acid. Myocardial hypertrophy, albuminuria, carotid intima-media thicknesses and ankle brachial index were assessed as HMOD presentations. Individuals were divided into two groups: patients with and without HMOD. We included 522 patients (47% women, mean age of 54 years). Multivariate logistic regression analysis showed that male patients older than 50 years old with uric acid levels above 7 mg/dL, ESR higher than 20 mm/h, fibrinogen greater than 320 mg/dL and PTC lower than 275 × 103/µL were associated with HMOD (p < 0.05). The circadian BP profile (dipper versus non-dipper pattern) did reach neither statistical significance nor influence the odds ratio of those inflammatory markers for HMOD. We found that differences in some inflammatory markers between patients with and without HMOD were not explained by a different circadian BP profile.
An impaired nocturnal decrease in diastolic blood pressure (DBP) increases the blood pressure (BP) load, which is a main factor in endothelial dysfunction, atherosclerosis, and arterial stiffness. We aimed to quantify some markers of oxidative stress in hypertensive patients, to compare their levels between individuals with dipper and non-dipper DBP profiles, and to assess their correlation with the nocturnal DBP (nDBP) dipping. It was an observational study that included patients older than 18 years with a diagnosis of essential hypertension who consented to participate. The collected variables were some indices of 24-h ambulatory blood pressure monitoring, demographic, epidemiological, clinical, and laboratory variables. Plasma thiobarbituric acid reactive substances (TBARS) and reduced thiols, together with serum vitamin E, vitamin A, copper (Cu), and zinc (Zn) levels were assessed as oxidative stress markers. We recruited 248 patients with a median age of 56 years (56% women). The percentage of nDBP dipping showed a weak positive correlation with reduced thiol, vitamin E, and vitamin A levels; and a weak negative correlation with Cu levels. We also found a negative correlation between nDBP dipping and the TBARS/Thiol, TBARS/Vitamin E, and TBARS/Vitamin A ratios. After multivariate analysis, we found that increased TBARS/Thiol ratio and serum Cu levels were associated with a higher risk of a non-dipper DBP profile. As in other situations of increased cardiovascular risk, an impaired nDBP decrease may coincide with abnormalities in redox status.
IntroductionInflammatory status could play a role in alterations of blood pressure (BP) circadian rhythm. The aim of our study is to compare levels of usual inflammatory markers in patients with and without circadian BP abnormalities.Material and methodsThis is a cross-sectional design study with retrospective data analysis which included patients from an Internal Medicine Department with normal and high BP levels older than 18 years who were separated into two groups according to the circadian profile of BP (dipper and non-dipper) based on the results of 24-hour ambulatory BP monitoring. Patients were assessed for demographic characteristics and cardiovascular risk factors. We considered as inflammatory markers the platelet count (PTC), erythrocyte sedimentation rate (ESR), ultra-sensitive C-reactive protein, ferritin, fibrinogen, and uric acid.ResultsThe study included 551 patients (mean age of 54 years, 47% women). The non-dipper group had a higher percentage of individuals with higher ESR (OR = 1.77, 95% CI: 1.23–1.55, p = 0.001), uric acid (OR = 1.50, 95% CI: 1.04–2.16, p = 0.028) and fibrinogen (OR = 1.72, 95% CI: 1.18–2.51, p = 0.001) and a higher percentage of patients with higher PTC (OR = 0.54, 95% CI: 0.37–0.78, p = 0.005). These results were independent of age, waist circumference, presence of arterial hypertension, diabetes or hyperlipidemia, and use of antihypertensive drugs including renin angiotensin aldosterone system blockers.ConclusionsPatients with impaired circadian BP rhythm were associated with an unfavorable inflammatory status independently of BP levels. This fact could play a role in the prognostic differences observed between dipper and non-dipper patients.
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