ABSTRACT
Mitochondrial dysfunctions are significant contributors to neurodegeneration. One result or a cause of mitochondrial dysfunction might be the disruption of mtDNA transcription. Limited data indicated an altered expression of mtDNA encoded transcripts in Alzheimer's disease (AD) or Parkinson's disease (PD). The number of mitochondria is high in cells with a high energy demand, such as muscle or nerve cells. AD or PD involves increased risk of cardiomyopathy, suggesting that mitochondrial dysfunction might be systemic. If it is systemic, we should observe it in different cell types. Given that, we wanted to investigate any disruption in the regulation of mtDNA encoded gene expression in addition to PINK1, PARKIN, and ATP levels in peripheral blood samples of PD cases who are affected by a neurodegenerative disorder that is very well known by its mitochondrial aspects. Our results showed for the first time that: 1) age of onsetâ>â50 PD sporadic (PDS) cases: mtDNA transcription and quality control genes were affected; 2) age of onset <50 PDS cases: only mtDNA transcription was affected; and 3) PD cases with familial background: only quality control genes were affected. mtDNA copy number was not a confounder. Intracellular ATP levels of PD case subgroups were significantly higher than those of healthy subjects. We suggest that a systemic dysregulation of transcription of mtDNA or mitochondrial quality control genes might result in the development of a sporadic form of the disease. Additionally, ATP elevation might be an independent compensatory and response mechanism. Hyperactive cells in AD and PD require further investigation.
Subject(s)
Adenosine Triphosphate/metabolism , DNA, Mitochondrial/genetics , Gene Expression Profiling , Genes, Mitochondrial/genetics , Oxidative Phosphorylation , Parkinson Disease/blood , Parkinson Disease/genetics , Adenosine Triphosphate/blood , Adult , Age of Onset , Aged , Blood Platelets/metabolism , Female , Gene Dosage , Humans , Male , Middle Aged , Monocytes/metabolism , Platelet Aggregation , Protein Kinases/blood , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Ubiquitin-Protein Ligases/bloodABSTRACT
To evaluate the role the coagulation and fibrinolysis abnormalities in the pathogenesis of ischemic stroke of undetermined etiology, we assayed plasma concentration of fibrinopeptide-A and thrombin-antithrombin III complex, both sensitive markers for thrombin activation and fibrin formation, and D-dimer, a marker of plasmin activity and fibrinolysis. Hemostatic markers were measured in 32 patients with acute stroke and 20 patients with chronic stroke, and compared with 21 normal subjects. Fibrinopeptid-A and thrombin-antithrombin III complex levels were not elevated significantly, whereas the D-dimer level was markedly raised in acute (p<< 0.001) and chronic (p< 0.05) phases of ischemic stroke in comparison with the control group. Prolonged elevation of D-dimer concentration suggests that hemostatic abnormalities have a primary role in the pathogenesis of ischemic stroke. The measurement of D-dimer concentration may help to better decide the indications for therapy of the patients with ischemic stroke of undetermined etiology.
