cytochrome-c-t and Multiple-Sclerosis

Blood platelets have been widely proposed as biomarkers in studies of mitochondrial function and aging-related and neurodegenerative diseases. Defects in mitochondrial function were found not only in the substantia nigra of Parkinson's disease patients but also in their blood platelets. Similarly, it has also been described in the blood platelet mitochondria of Alzheimer's disease patients. To study mitochondrial aerobic metabolism function and protein expression in platelets of multiple sclerosis (MS) patients and control subjects, mitochondrial aconitase, mitochondrial superoxide dismutases 1 and 2 (SOD1 and SOD2), and respiratory complex enzyme activities in platelets of MS patients and control subjects were determined. Likewise, mitochondrial lipid peroxidation and mitochondrial SOD1 and cytochrome c expressions were investigated. Mitochondrial aconitase activity was higher in MS patients than in controls (P < 0.05). A significant increase on all respiratory complex activities in MS patients was observed (P < 0.05). Mitochondrial lipid peroxidation was significantly higher in MS patients than in controls (P < 0.05). Significant changes of cytochrome c and mitochondrial SOD1 expressions were detected (P < 0.05), with a decrease of 44 ± 5 % and an increase of 46 ± 6 %, respectively. Our study reveals that significant changes in mitochondrial aerobic metabolism function and mitochondrial SOD1 and cytochrome c expressions are produced in platelets of MS patients.

Topics: Animals; Blood Platelets; Cytochromes c; Enzyme Activation; Gene Expression Regulation, Enzymologic; Humans; Mitochondrial Proteins; Multiple Sclerosis; Superoxide Dismutase; Superoxide Dismutase-1

Apoptotic deletion of autoreactive T-cells is defective in patients with multiple sclerosis (MS). Glatiramer acetate (GA) treatment seems to restore apoptosis of detrimental T-cells. We analyzed the mitochondria membrane pro- (Bax) and anti-apoptotic (Bcl- 2) and cytosolic pro-apoptotic (Cyt-c, APAF-1) proteins expression in peripheral lymphocytes from relapsing-remitting (RR) MS patients during GA treatment. Blood samples were collected from 8 healthy controls (HCs) and from 8 RR MS patients prior to and every three months during the 9 months of GA treatment. Peripheral blood mononuclear cells (PBMNCs) Bcl-2, Bax, Cyt-c and APAF-1 were quantified by western blot followed by densitometric scanning and Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios were calculated. T-cells were in vitro tested for oxygen consumption by a respirometric analysis. Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios in untreated MS patients were significantly (p < 0.05) lower than in HCs. Bax/Bcl-2 ratio increased (p = 0.03) and Cyt-c/Bcl-2 ratio showed a trend to increase during the 9 months of GA treatment in MS patients. A reduction of 58% and 59% in oxygen consumption by PBMNCs was evident after GA treatment in vitro or when GA treated patients' cells were compared with those from HCs, respectively. Our findings suggest that GA exerts a regulatory effect on peripheral T lymphocytes through pro-apoptosis mechanisms involving mitochondria and cytosolic proteins.

Topics: Adult; Apoptosis; Apoptosis Regulatory Proteins; Apoptotic Protease-Activating Factor 1; bcl-2-Associated X Protein; Blotting, Western; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Case-Control Studies; Cytochromes c; Female; Glatiramer Acetate; Humans; Immunosuppressive Agents; Intracellular Signaling Peptides and Proteins; Lymphocytes; Male; Middle Aged; Multiple Sclerosis; Oxygen Consumption; Peptides; Proteins; Proto-Oncogene Proteins c-bcl-2; Rotenone; Statistics, Nonparametric; Time Factors; Uncoupling Agents

Axonal pathology in multiple sclerosis (MS) has been described for over a century, but new insights into axonal loss and disability have refocused interest in this area. There is evidence of oxidative damage to mitochondrial DNA in chronic MS plaques, suggesting that mitochondrial failure may play a role in MS pathology. We propose that in the chronic absence of myelin the maintenance of conduction relies partially on an increase in mitochondria to provide energy. This increased energy requirement also promotes reactive oxygen species (ROS), because most intraaxonal ROS are generated by mitochondria. If antioxidant defenses are overwhelmed by an excess of ROS, this may result in damage to the axon. Our aim was to investigate whether a chronic lack of myelin results in adaptive changes involving mitochondria within the axon. We investigated this in the shiverer mouse. This myelin basic protein gene mutant provides a model of how adult central nervous system (CNS) axons cope with the chronic absence of a compact myelin sheath. Cytochrome c histochemistry demonstrated a twofold increase in mitochondrial activity in white matter tracts of shiverer, and electron microscopy confirmed a significantly higher number of mitochondria within the dysmyelinated axons. Our data demonstrate that there are adaptive changes involving mitochondria occurring within CNS axons in shiverer mice in response to a lack of myelin. This work contributes to our understanding of the adaptive changes occurring in response to a lack of myelin in a noninflammatory environment similar to the situation seen in chronically demyelinated MS plaques.

Topics: Adaptation, Physiological; Animals; Axons; Cytochromes c; Disease Models, Animal; Energy Metabolism; Histocytochemistry; Male; Mice; Mice, Neurologic Mutants; Microscopy, Electron, Transmission; Mitochondria; Multiple Sclerosis; Myelin Sheath; Nerve Fibers, Myelinated; Up-Regulation; Wallerian Degeneration