Mitochondrial dysfunction has been reported in most neurodegenerative diseases. These anomalies include bioenergetic defect, respiratory chain-induced oxidative stress, defects of mitochondrial dynamics, increase sensitivity to apoptosis, and accumulation of damaged mitochondria with instable mitochondrial DNA. Significant progress has been made in our understanding of the pathophysiology of inherited mitochondrial disorders but most have no effective therapies. The development of new metabolic treatments will be useful not only for rare mitochondrial disorders but also for the wide spectrum of common age-related neurodegenerative diseases shown to be associated with mitochondrial dysfunction. A better understanding of the mitochondrial regulating pathways raised several promising perspectives of neuroprotection. This review focuses on the pharmacological approaches to modulate mitochondrial biogenesis, the removal of damaged mitochondria through mitophagy, scavenging free radicals and also dietary measures such as ketogenic diet.
[Show abstract][Hide abstract] ABSTRACT: Traumatic brain injury (TBI) is still the leading cause of disability in young adults worldwide. The major mechanisms - diffuse axonal injury, cerebral contusion, ischemic neurological damage, and intracranial hematomas have all been shown to be associated with mitochondrial dysfunction in some form. Mitochondrial dysfunction in TBI patients is an active area of research, and attempts to manipulate neuronal/astrocytic metabolism to improve outcomes have been met with limited translational success. Previously, several preclinical and clinical studies on TBI induced mitochondrial dysfunction have focused on opening of the mitochondrial permeability transition pore (PTP), consequent neurodegeneration and attempts to mitigate this degeneration with cyclosporine A (CsA) or analogous drugs, and have been unsuccessful. Recent insights into normal mitochondrial dynamics and into diseases such as inherited mitochondrial neuropathies, sepsis and organ failure could provide novel opportunities to develop mitochondria-based neuroprotective treatments that could improve severe TBI outcomes. This review summarizes those aspects of mitochondrial dysfunction underlying TBI pathology with special attention to models of penetrating traumatic brain injury, an epidemic in modern American society.
Journal of Bioenergetics 10/2014; 47(1-2). DOI:10.1007/s10863-014-9589-1 · 3.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Succinobucol (succinyl ester of probucol) is a lipid-lowering compound with anti-inflammatory and antioxidant properties. Recent experimental evidence has highlighted the potential neuroprotective effects of succinobucol. In the present study, cultured neuroblastoma (SH-SY5Y) cells were used to investigate mechanisms mediating the potential protective effect of succinobucol against mitochondrial metabolic impairment and oxidative stress induced by 3-nitropropionic acid (3-NP), a succinate dehydrogenase inhibitor that has been used in experimental models of the Huntington disease (HD). 3-NP decreased cellular viability after 24 h of incubation. This decline in cellular viability was preceded by (i) reduced mitochondrial complex II activity, (ii) increased reactive species generation, (iii) decreased mitochondrial membrane potential (ΔΨm), and (iv) diminished glutathione (GSH) levels. Succinobucol pretreatment (6 days) significantly prevented 3-NP-induced loss of cellular viability, generation of reactive oxygen species, and decrease of ΔΨm. However, succinobucol pretreatment did not protect against 3-NP-induced inhibition of mitochondrial complex II activity, pointing to the mitigation of secondary events resultant from mitochondrial complex II inhibition. Succinobucol pretreatment (6 days) significantly increased (50 %) the levels of GSH in SH-SY5Y cells, and this event was paralleled by significant increases in glutamate cysteine ligase messenger RNA (mRNA) expression and activity (GCL; the first enzyme in the GSH biosynthesis). The present findings are the first to show that succinobucol increases GSH levels via upregulation of GCL activity (possibly through the activation of the nuclear (erythroid-derived 2)-related factor (Nrf2)/antioxidant response element (ARE) pathway), displaying protective effects against mitochondrial dysfunction-derived oxidative stress.
[Show abstract][Hide abstract] ABSTRACT: To differentiate the bioelectrical cortical responses driven by axons from central and mid-peripheral retina in Leber's hereditary optic neuropathy (LHON) by using multifocal visual evoked potentials (mfVEP).
Seventeen genetically confirmed LHON patients (33.35 ± 8.4 years, 17 eyes) and 22 age-matched controls (C) (38.2 ± 6.0 years, 22 eyes) were studied by mfVEP and optical coherence tomography. MfVEP P1 implicit time (P1 IT, ms) and response amplitude density of the N1-P1 components (N1-P1 RAD, nV/deg(2)) of the second order binary kernel were measured for five concentric retinal areas between the fovea and mid-periphery: 0-20 degrees (R1 to R5).
Mean mfVEP P1 ITs and N1-P1 RADs at all five foveal eccentricities were significantly different (p < 0.01) in LHON when compared to controls. In both groups, mean mfVEP responses obtained from R1 to R5 showed a progressive shortening of P1 ITs (linear fitting, LHON: r = -0.95; C: r = -0.98) and decrease of N1-P1 RADs (exponential fitting, LHON: r (2) = 0.94; C: r (2) = 0.93). The slope of the linear fitting between mean mfVEP P1 ITs in the two groups was about three times greater in LHON than in controls (LHON: y = -13.33x +182.03; C: y = -4.528x +108.1). MfVEP P1 ITs detected in R1 and R2 (0-5 degrees) were significantly correlated (p < 0.01) with the reduction of retinal nerve fiber layer thickness of the temporal quadrant.
MfVEP identifies abnormal neural conduction along the visual pathways in LHON, discriminating a predominant involvement of axons driving responses from the central retina when compared to those serving the mid-peripheral retina.
Albrecht von Graæes Archiv für Ophthalmologie 03/2015; 253(9). DOI:10.1007/s00417-015-2979-1 · 1.91 Impact Factor
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