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Peripheral Blood Mitochondrial DNA as a Biomarker of Cerebral Mitochondrial Dysfunction following Traumatic Brain Injury in a Porcine Model.

Kilbaugh TJ, Lvova M, Karlsson M, Zhang Z, Leipzig J, Wallace DC, Margulies SS - PLoS ONE (2015)

Bottom Line: At 6 and 25 h after diffuse non-impact TBI, mean mtDNA copy number was significantly higher: 2.07 ± 0.19 (P < 0.0001) and 2.37 ± 0.42 (P < 0.001), respectively.Following focal impact TBI, relative mtDNA copy number was also significantly higher, 1.35 ± 0.12 (P < 0.0001) at 25 hours.Alterations in peripheral blood relative mtDNA copy numbers may be a novel biosignature of cerebral mitochondrial bioenergetics with exciting translational potential for non-invasive diagnostic and interventional studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: Traumatic brain injury (TBI) has been shown to activate the peripheral innate immune system and systemic inflammatory response, possibly through the central release of damage associated molecular patterns (DAMPs). Our main purpose was to gain an initial understanding of the peripheral mitochondrial response following TBI, and how this response could be utilized to determine cerebral mitochondrial bioenergetics. We hypothesized that TBI would increase peripheral whole blood relative mtDNA copy number, and that these alterations would be associated with cerebral mitochondrial bioenergetics triggered by TBI.

Methodology: Blood samples were obtained before, 6 h after, and 25 h after focal (controlled cortical impact injury: CCI) and diffuse (rapid non-impact rotational injury: RNR) TBI. PCR primers, unique to mtDNA, were identified by aligning segments of nuclear DNA (nDNA) to mtDNA, normalizing values to nuclear 16S rRNA, for a relative mtDNA copy number. Three unique mtDNA regions were selected, and PCR primers were designed within those regions, limited to 25-30 base pairs to further ensure sequence specificity, and measured utilizing qRT-PCR.

Results: Mean relative mtDNA copy numbers increased significantly at 6 and 25 hrs after following both focal and diffuse traumatic brain injury. Specifically, the mean relative mtDNA copy number from three mitochondrial-specific regions pre-injury was 0.84 ± 0.05. At 6 and 25 h after diffuse non-impact TBI, mean mtDNA copy number was significantly higher: 2.07 ± 0.19 (P < 0.0001) and 2.37 ± 0.42 (P < 0.001), respectively. Following focal impact TBI, relative mtDNA copy number was also significantly higher, 1.35 ± 0.12 (P < 0.0001) at 25 hours. Alterations in mitochondrial respiration in the hippocampus and cortex post-TBI correlated with changes in the relative mtDNA copy number measured in peripheral blood.

Conclusions: Alterations in peripheral blood relative mtDNA copy numbers may be a novel biosignature of cerebral mitochondrial bioenergetics with exciting translational potential for non-invasive diagnostic and interventional studies.

No MeSH data available.


Related in: MedlinePlus

Association between peripheral blood mtDNA copy number and cerebral bioenergetics 6 hours and 25 hours after rapid, non-impact rotational (RNR) traumatic brain injury.(A) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation 6 hours post-RNR from sham respiration values. RNR: rapid non-impact rotational traumatic brain injury. (B) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation (OXPHOSCI+CII) 25 hours post-RNR from sham respiration. RNR: rapid non-impact rotational traumatic brain injury.
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pone.0130927.g005: Association between peripheral blood mtDNA copy number and cerebral bioenergetics 6 hours and 25 hours after rapid, non-impact rotational (RNR) traumatic brain injury.(A) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation 6 hours post-RNR from sham respiration values. RNR: rapid non-impact rotational traumatic brain injury. (B) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation (OXPHOSCI+CII) 25 hours post-RNR from sham respiration. RNR: rapid non-impact rotational traumatic brain injury.

Mentions: Six hours after TBI we found that larger increases in relative mtDNA copy number in peripheral blood after RNR from pre-injury concentrations were significantly correlated with lower maximal oxidative phosphorylation (OXPHOSCI+CII; pmols O2/s*mg) in the hippocampus (P <0.01) (Fig 5A) compared to sham respiration. Furthermore, there was a significant correlation 25 hours post-RNR between increases in relative mtDNA copy number and lower hippocampal RCR values (P < 0.04) (Fig 5B). Animals who underwent CCI were found to have a significant correlation 25 hours after injury between increased relative mtDNA copy number and lower maximal oxidative phosphorylation (OXPHOSCI+CII; pmols O2/s*mg) in the peri-contusional tissue in the ipsilateral hemisphere (P < 0.02) (Fig 6) compared to sham respiration.


Peripheral Blood Mitochondrial DNA as a Biomarker of Cerebral Mitochondrial Dysfunction following Traumatic Brain Injury in a Porcine Model.

Kilbaugh TJ, Lvova M, Karlsson M, Zhang Z, Leipzig J, Wallace DC, Margulies SS - PLoS ONE (2015)

Association between peripheral blood mtDNA copy number and cerebral bioenergetics 6 hours and 25 hours after rapid, non-impact rotational (RNR) traumatic brain injury.(A) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation 6 hours post-RNR from sham respiration values. RNR: rapid non-impact rotational traumatic brain injury. (B) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation (OXPHOSCI+CII) 25 hours post-RNR from sham respiration. RNR: rapid non-impact rotational traumatic brain injury.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4476697&req=5

pone.0130927.g005: Association between peripheral blood mtDNA copy number and cerebral bioenergetics 6 hours and 25 hours after rapid, non-impact rotational (RNR) traumatic brain injury.(A) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation 6 hours post-RNR from sham respiration values. RNR: rapid non-impact rotational traumatic brain injury. (B) There was a significant correlation between the increase in peripheral blood relative mtDNA quantification copy number (RQ), from pre- to post-injury and the decrease in hippocampal maximal oxidative phosphorylation (OXPHOSCI+CII) 25 hours post-RNR from sham respiration. RNR: rapid non-impact rotational traumatic brain injury.
Mentions: Six hours after TBI we found that larger increases in relative mtDNA copy number in peripheral blood after RNR from pre-injury concentrations were significantly correlated with lower maximal oxidative phosphorylation (OXPHOSCI+CII; pmols O2/s*mg) in the hippocampus (P <0.01) (Fig 5A) compared to sham respiration. Furthermore, there was a significant correlation 25 hours post-RNR between increases in relative mtDNA copy number and lower hippocampal RCR values (P < 0.04) (Fig 5B). Animals who underwent CCI were found to have a significant correlation 25 hours after injury between increased relative mtDNA copy number and lower maximal oxidative phosphorylation (OXPHOSCI+CII; pmols O2/s*mg) in the peri-contusional tissue in the ipsilateral hemisphere (P < 0.02) (Fig 6) compared to sham respiration.

Bottom Line: At 6 and 25 h after diffuse non-impact TBI, mean mtDNA copy number was significantly higher: 2.07 ± 0.19 (P < 0.0001) and 2.37 ± 0.42 (P < 0.001), respectively.Following focal impact TBI, relative mtDNA copy number was also significantly higher, 1.35 ± 0.12 (P < 0.0001) at 25 hours.Alterations in peripheral blood relative mtDNA copy numbers may be a novel biosignature of cerebral mitochondrial bioenergetics with exciting translational potential for non-invasive diagnostic and interventional studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: Traumatic brain injury (TBI) has been shown to activate the peripheral innate immune system and systemic inflammatory response, possibly through the central release of damage associated molecular patterns (DAMPs). Our main purpose was to gain an initial understanding of the peripheral mitochondrial response following TBI, and how this response could be utilized to determine cerebral mitochondrial bioenergetics. We hypothesized that TBI would increase peripheral whole blood relative mtDNA copy number, and that these alterations would be associated with cerebral mitochondrial bioenergetics triggered by TBI.

Methodology: Blood samples were obtained before, 6 h after, and 25 h after focal (controlled cortical impact injury: CCI) and diffuse (rapid non-impact rotational injury: RNR) TBI. PCR primers, unique to mtDNA, were identified by aligning segments of nuclear DNA (nDNA) to mtDNA, normalizing values to nuclear 16S rRNA, for a relative mtDNA copy number. Three unique mtDNA regions were selected, and PCR primers were designed within those regions, limited to 25-30 base pairs to further ensure sequence specificity, and measured utilizing qRT-PCR.

Results: Mean relative mtDNA copy numbers increased significantly at 6 and 25 hrs after following both focal and diffuse traumatic brain injury. Specifically, the mean relative mtDNA copy number from three mitochondrial-specific regions pre-injury was 0.84 ± 0.05. At 6 and 25 h after diffuse non-impact TBI, mean mtDNA copy number was significantly higher: 2.07 ± 0.19 (P < 0.0001) and 2.37 ± 0.42 (P < 0.001), respectively. Following focal impact TBI, relative mtDNA copy number was also significantly higher, 1.35 ± 0.12 (P < 0.0001) at 25 hours. Alterations in mitochondrial respiration in the hippocampus and cortex post-TBI correlated with changes in the relative mtDNA copy number measured in peripheral blood.

Conclusions: Alterations in peripheral blood relative mtDNA copy numbers may be a novel biosignature of cerebral mitochondrial bioenergetics with exciting translational potential for non-invasive diagnostic and interventional studies.

No MeSH data available.


Related in: MedlinePlus