A study indicates that deletions, alterations of the Mitochondrial DNA that suppose the loss of genetic material in the sequence of DNAthere are years before the appearance of the motor and cognitive symptoms of Parkinson.
In depth
CSIC researchers, the Clinic-IDIBAPS Hospital and the University of Barcelona They have analyzed samples of 71 patients with sleep behavior disorders in the REM phase, considered An initial stage of Parkinson’s disease.
The study, published in the magazine ‘Ebiomedicine ‘of the group ‘The Lancet‘, shows that patients with this type of disorder present in the cerebrospinal fluid high levels of mitochondrial DNA with deletions, mutations in which the DNA sequence has lost some fragment of the genetic material, which act as they act as Primary molecular mechanism of the neurodegenerative process associated with the appearance of Parkinson’s motor and cognitive symptoms.
Parkinson’s disease is associated with dysfunction in mitochondriathe organelles in charge, among other things, of supplying energy to the cells. Some studies have shown that in the cerebrospinal fluid of Parkinson’s patients it is observed that mitochondrial DNA has defects, which would be an indicator of that defective operation. However, what is Without clarifying is whether that mitochondrial malfunction is a consequence of Parkinson’s disease or is prior, and is one of the causes of the disease.
More details
This is what a team led by Ramon Trullas, a CSIC researcher at the Barcelona Biomedical Research Institute (IIBB-CSIC) and Alex Iranzo, of the Neurology Service of the Clinic Hospital of Barcelona and the University of Barcelona, and head of the Clinical Neurophysiology Research Group of IDIBAPS; both linked to cyber of neurodegenerative diseases (CIBERNED).
At work, researchers have studied a cohort of patients with sleep behavior disorder during PHASE REM (IRBD). This disorder consists of an alteration of the deep sleep phase that is characterized by the lack of muscle relaxation and the execution of Sudden and violent movements of the limbs and trunk that may be related to aggressive dreams.
Many patients with that disorder end up developing, after years, or parkinson or dementia of bodies of Lewywhich is why it is considered that it could be an early stage of these diseases. In both, round and abnormal protein deposits (called Lewy bodies) and andn the brain associated with the death of neurons.
The survival of neurons, unlike most body cells, depends largely on the energy provided by mitochondria, which are intracellular organelles that have their own DNA for work properly. The presence of circulating mitochondrial DNA indicates that mitochondria cannot provide sufficient energy so that neurons maintain their long -term activity and survival.
In collaboration with the Sleep Disorders Unit of the Clinic Hospital in Barcelona, the team has been able to analyze samples of 71 patients. Of these, 34 were diagnosed with sleep behavior disorder during the REM phase and, years later, they developed Parkinson’s disease or Lewy bodies dementia; 17 were also diagnosed with sleep behavior disorder in the REM phase, but remained free of disease; and 20 formed a control group without sleep behavior disorder or parkinsonism.
“We have found that patients with DNA -phase behavior disorder have higher DNA levels Mitochondrial with delegations compared to the control group“, points out the research professor of the CSIC and leader of the Ciberned Group Molecular Mechanisms of Neurodegeneration, Ramon Trullás.
To take into account
For her part, the IIBB-CSIC researcher and first author of the work, Margalida Puigrs, He explains that “patients with sleep behavior disorder in ReM phase, both those who developed Parkinson later and those who did not present more circulating mitochondrial ADN with deletions -that is, that, that They have lost some fragment of genetic material- in the cerebrospinal fluid that the control group“
“But the most relevant finding is that we have observed that the amount of DNA with deletions is related to the time when patients with sleep behavior disorder will take to manifest the clinical symptoms of Parkinson’s disease,” he adds. This indicates that, more deletions, the disease will appear before.
These results suggest that Mitochondrial DNA dan.
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