Plasma Mitochondrial DNA Research Articles

Plasma mitochondrial DNA levels are inversely associated with HIV-RNA levels and directly with CD4 counts: potential role as a biomarker of HIV replication.

To evaluate plasma mitochondrial DNA (mtDNA) levels among HIV-infected patients and its potential role as a biomarker of residual viral replication. HIV-infected patients on follow-up at a reference hospital in north-west Spain were selected. DNA was isolated from plasma samples and mtDNA levels were assessed using a quantitative real-time PCR assay. HIV-RNA levels and CD4+ cell counts were evaluated in the same blood samples used for plasma mtDNA quantification. Epidemiological and clinical variables were included for the analysis. A total of 235 HIV-infected patients were included. Mean plasma mtDNA levels were 217 ± 656 copies/μL for naive (31.9%) and 364 ± 939 copies/μL for HIV-infected patients receiving ART and with suppressed viraemia (P = 0.043). Among the latter, mean plasma mtDNA levels were 149 ± 440 copies/μL for those with low-level viraemia (LLV; HIV-RNA 20-200 copies/mL), 265 ± 723 copies/μL for those with detected-not-quantified (DNQ) viraemia (HIV-RNA <20 copies/mL) and 644 ± 1310 copies/μL for those with not-detected (ND) viraemia. Of note, a linear trend (P = 0.006) was observed among virologically suppressed (LLV, DNQ and ND) patients. ND patients had higher mtDNA levels compared with LLV patients (P = 0.057). Moreover, mtDNA levels were inversely associated with HIV-RNA levels (Spearman's rho -0.191, P = 0.003) and directly associated with CD4+ counts (Spearman's rho 0.131, P = 0.046). Increased plasma mtDNA levels are associated with lower HIV-RNA levels and higher CD4+ cell counts. Among ART-suppressed patients, mtDNA levels were significantly higher in those with complete virological suppression (ND) than in those with LLV. These data suggest that plasma mtDNA levels might serve as a biomarker of residual HIV replication.

Elevated Levels of Plasma Mitochondrial DNA Are Associated with Clinical Outcome in Intra-Abdominal Infections Caused by Severe Trauma.

The purpose of our study was to determine prospectively relationships between plasma mitochondrial deoxyribonucleic acid (mtDNA) concentration and clinical outcome in patients with intra-abdominal infections (IAIs) induced by severe abdominal trauma. The DNA was isolated from serum samples taken from patients with IAIs at hospital days zero, one, and two. Plasma mtDNA concentration was assessed by real-time polymerase chain reaction (PCR). The study population's clinical and laboratory data were analyzed. The mtDNA damage-associated molecular patterns were expressed as a PCR threshold cycle number using four selected sequences. The patients with IAIs had significant higher plasma mtDNA than healthy control subjects. Patients with IAIs with sepsis apparently had elevated mtDNA levels compared with non-septic patients with IAIs (30.9 ± 2.0 vs. 28.7 ± 2.4; 33.3 ± 2.6 vs. 28.9 ± 2.4; 32.9 ± 1.6 vs. 31.2 ± 2.2; 33.1 ± 3.6 vs. 28.1 ± 2.2, respectively). Patients with IAIs in whom multiple organ dysfunction syndrome (MODS) developed also had increased mtDNA concentration compared with those who did not (31.0 ± 1.8 vs. 27.9 ± 1.8; 32.9 ± 2.4 vs. 27.8 ± 1.7; 32.9 ± 1.5 vs. 29.8 ± 1.7; 32.0 ± 3.8 vs. 27.1 ± 2.1, respectively). Baseline mtDNA concentration had high effectiveness in predicting death for patients with IAIs who had severe trauma using receiver operating characteristic analysis. Furthermore, serum mtDNA levels on admission correlated with the lactate concentration, but no significant correlations were found between mtDNA levels and levels of white blood cells, C-reactive protein, and procalcitonin. Plasma mtDNA was associated with the occurrence of sepsis, MODS, and death in patients with IAIs caused by severe abdominal trauma.

Perioperative plasma mitochondrial DNA dynamics and correlation with inflammation during infantile cardiopulmonary bypass

ObjectiveNumerous studies in animals and humans have demonstrated that inflammatory mediators such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 play a role in cardiopulmonary bypass (CPB), which might affect surgical outcomes. Plasma mitochondrial DNA (mtDNA), a recently discovered pro-inflammatory agent, is released by cells upon insult. This study aimed to detect changes in plasma mtDNA levels at different time points after infantile CPB and explore its potential association with inflammatory mediators. MethodsIn the present study, we analyzed the perioperative plasma mtDNA and inflammatory cytokine levels of 48 infants undergoing ventricular septal defect closure. Blood samples were collected before aortic cross-clamping (T1), at the end of CPB (T2), and 6h (T3), 12h (T4), and 24h (T5) post-CPB. Reverse transcription–polymerase chain reaction and specific enzyme-linked immunosorbent assay were used to quantify the plasma mtDNA and inflammatory cytokines, respectively. Bivariate correlation analysis was used to determine the correlations between plasma mtDNA and inflammatory cytokines. ResultsPlasma mtDNA levels increased at T2 and peaked at T3. Significant positive correlations were found between peak plasma mtDNA (at T3) and several inflammatory biomarkers, including IL-6 (at T3) (r=0.62, P<0.001), IL-8 (at T2) (r=0.53, P<0.001), and TNF-α (at T3) (r=0.61, P<0.001). ConclusionHere we report that mtDNA may participate in a systemic inflammatory response to CPB.

Plasma mitochondrial DNA levels were independently associated with lung injury in elderly hip fracture patients

IntroductionHip fracture in the elderly can induce systemic inflammatory response (SIRS) and lung injury which increases the risk of lung infection and death. Mitochondrial DNA (mtDNA) plays a role in SIRS and lung injury in patients with multi-trauma, and also in patients with hip fractures. This study evaluated the potential value of plasma mtDNA in the early prognosis of lung injury in elderly fracture patients. MethodsThis study enrolled 156 elderly patients with intertrochanteric fracture. Plasma mtDNA, IL-6, IL-10, prostaglandin E2 (PGE2) levels were measured at admission. Sixty-one and 31 patients were diagnosed with systemic inflammatory response syndrome (SIRS) and lung injury, respectively. ResultsPlasma mtDNA levels were higher in hip fracture patients compared to healthy controls (P<0.001) and significantly higher in the lung injury subgroup compared to the lung injury absent subgroup (P<0.001). MtDNA levels were correlated with the SIRS score (r=0.446, P<0.001), IL-6 (r=0.506, P<0.001), IL-10 (r=0.523, P<0.001), and PGE2 (r=0.360, P<0.001). Logistic regression analysis revealed that plasma mtDNA, IL-6, PGE2 and SIRS score were independent predictors of the risk of lung injury. ConclusionPlasma mtDNA release induced by hip fracture in elderly patients, might be an early predictor of lung injury in these patients.

Plasma mitochondrial DNA at admission can predict the outcome of acute trauma patients admitted to ICU

ObjectivesWe assessed whether at admission plasma circulating cell free mitochondrial DNA (ccf-mtDNA) is related to injury severity and can predict morbidity and mortality in acute trauma patients.Patients and methodsPatients were evaluated at Emergency Department (ED) using Injury Severity Scale (ISS), but only patients required ICU admission were studied (Group B). At ED arrival, blood samples were obtained for quantitative real-time PCR estimation of plasma level of ccf-mtDNA. Study outcome was the correlation between morbidity and mortality and at admission plasma ccf-mtDNA level and its predictability for morbidity and mortality. Ten healthy volunteers gave blood samples as control group (Group B).ResultsTwenty-seven patients passed smooth ICU stay and were discharged alive (Group B1), while 34 patients developed additional morbidities (Group B2) and 11 patients (18%) of Group A2 died. Mean estimated plasma ccf-mtDNA levels were significantly higher in Group B than in Group A, but patients of Group B1 had significantly lower ccf-mtDNA levels than patients of Group B2. Patients developed adult respiratory distress syndrome (ARDS) had significantly higher ccf-mtDNA levels than patients developed sepsis or acute myocardial infarction (AMI) with significantly higher levels in patients developed sepsis. Estimated plasma ccf-mtDNA levels at time of admission showed positive significant correlation with morbidity rate. Odds ratio (OR) for relative risk for development of additional morbidities in patients who had a high plasma ccf-mtDNA level was 26.35. At admission plasma ccf-mtDNA levels in survivors were significantly lower than in non-survivors, and OR was 4.0806. High plasma ccf-mtDNA showed high sensitivity as predictor for ICU mortality.ConclusionHigh at ED admission plasma ccf-mtDNA levels could predict development of additional morbidities during ICU stay of acute trauma patients and showed high sensitivity for prediction of their survival. Very high plasma ccf-mtDNA levels could predict patients liable to develop ARDS.

Potential Mechanism of Post-Acute Aortic Dissection Inflammatory Responses: The Role of mtDNA from Activated Platelets

Background: Acute aortic dissection (AD) is a lethal cardiovascular disease with severe inflammatory complications. Considering the proinflammatory properties of plasma mitochondrial DNA (mtDNA), we postulate that plasma mtDNA from activated platelets may be responsible for post-acute AD inflammatory responses. Methods: We consecutively enrolled 68 patients with acute AD as well as matched hypertensive and healthy participants. Blood samples were collected on admission for blood routine tests, mtDNA assay, and inflammatory cytokine analysis. A computed tomography scan was used to evaluate the extent of dissections. Results: Our results demonstrate that plasma mtDNA, platelet activation, and inflammatory levels were remarkably higher in acute AD patients than in hypertensive or healthy participants. These parameters were also higher in the Stanford A group than in the Stanford B group (p < 0.05). Bivariate correlation analysis demonstrated positive associations between mtDNA and inflammatory levels (tumor necrosis factor-α: r = 0.577; interleukin-6: r = 0.632), mtDNA and platelet activation (r = 0.642), and platelet activation and the extent of dissection (r = 0.635). Conclusion: Our study suggests that acute AD-induced tunica media exposure causes platelet activation, which leads to the initiation of inflammatory responses via the release of mtDNA into the circulation. Our study provides a novel fundamental basis and a potential therapeutic target for the prevention and treatment of post-AD inflammatory responses.

Platelets activation is associated with elevated plasma mitochondrial DNA during cardiopulmonary bypass.

BackgroundMitochondrial DNA (mtDNA) was reported as a pro-inflammatory agent. In our previous study, elevation of plasma mtDNA was revealed after cardiac surgery with cardiopulmonary bypass (CPB). Platelets were activated during the cardiac surgery and recent study revealed its ability to release mtDNA. Our present study postulated that the elevated plasma mtDNA comes from activated platelets, which plays a critical role in post-CPB inflammatory responses.MethodsSixty-eight patients who underwent coronary artery bypass graft (CABG) with CPB were enrolled in our study. Blood samples were collected before induction of anaesthesia (T1), at the end of CPB (T2), 12 h post-CPB (T3), 24 h post-CPB (T4), 48 h post-CPB (T5) and 72 h post-CPB (T6). Blood samples were analyzed for the routine blood test and prepared for plasma isolation. MtDNA concentration was measured by rt-PCR, and TNF-α and IL-6 were examined by specific ELISA kits. Subgroup study was analyzed by activation levels of platelet. Basic information, mtDNA level, TNF-α level and IL-6 level were all carefully studied in each quartile.ResultsActivation level of platelets increased and peaked at T2, which decreased gradually from T3 to T6 (P < 0.05). MtDNA increased after CPB, peaked at T3, and then backed from T4 to T6 (P < 0.05). Bivariate correlation between peak activation level of platelets and peak plasma mtDNA level showed a positive correlation between these two parameters (r = 0.683, P < 0.0001). Both TNF-α and IL-6 showed similar patterns as mtDNA, with an increase from T1 to T3 and a decrease from T4 to T6 (P < 0.05). Subgroup analysis further demonstrated that patients with higher activation levels of PLT had higher plasma mtDNA levels and inflammatory level (P < 0.05).ConclusionsOur study revealed the dynamic changes of activation level of platelets and identified the interesting association between platelets activation and plasma mtDNA, suggesting a novel potential mechanism of activated platelets-induced post-CPB inflammatory responses.

PS71. A Clinical Pilot Study of Plasma Mitochondrial DNA as a Biomarker for Bipolar Disorder

PS71. A Clinical Pilot Study of Plasma Mitochondrial DNA as a Biomarker for Bipolar Disorder

Aberrant Inflammasome Activation Characterizes Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome.

Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) complicates combination antiretroviral therapy (cART) in up to 25% of patients with HIV/TB coinfection. Monocytes and IL-18, a signature cytokine of inflammasome activation, are implicated in TB-IRIS pathogenesis. In this study, we investigated inflammasome activation both pre- and post-cART in TB-IRIS patients. HIV/TB patients exhibited higher proportions of monocytes expressing activated caspase-1 (casp1) pre-cART, compared with HIV patients without TB, and patients who developed TB-IRIS exhibited the greatest increase in casp1 expression. CD64(+) monocytes were a marker of increased casp1 expression. Furthermore, IL-1β, another marker of inflammasome activation, was also elevated during TB-IRIS. TB-IRIS patients also exhibited greater upregulation of NLRP3 and AIM2 inflammasome mRNA, compared with controls. Analysis of plasma mitochondrial DNA levels showed that TB-IRIS patients experienced greater cell death, especially pre-cART. Plasma NO levels were lower both pre- and post-cART in TB-IRIS patients, providing evidence of inadequate inflammasome regulation. Plasma IL-18 levels pre-cART correlated inversely with NO levels but positively with monocyte casp1 expression and mitochondrial DNA levels, and expression of IL-18Rα on CD4(+) T cells and NK cells was higher in TB-IRIS patients, providing evidence that IL-18 is a marker of inflammasome activation. We propose that inflammasome activation in monocytes/macrophages of HIV/TB patients increases with ineffective T cell-dependent activation of monocytes/macrophages, priming them for an excessive inflammatory response after cART is commenced, which is greatest in patients with TB-IRIS.

Altered Striatocerebellar Metabolism and Systemic Inflammation in Parkinson's Disease.

Parkinson's disease (PD) is the most second common neurodegenerative movement disorder. Neuroinflammation due to systemic inflammation and elevated oxidative stress is considered a major factor promoting the pathogenesis of PD, but the relationship of structural brain imaging parameters to clinical inflammatory markers has not been well studied. Our aim was to evaluate the association of magnetic resonance spectroscopy (MRS) measures with inflammatory markers. Blood samples were collected from 33 patients with newly diagnosed PD and 30 healthy volunteers. MRS data including levels of N-acetylaspartate (NAA), creatine (Cre), and choline (Cho) were measured in the bilateral basal ganglia and cerebellum. Inflammatory markers included plasma nuclear DNA, plasma mitochondrial DNA, and apoptotic leukocyte levels. The Cho/Cre ratio in the dominant basal ganglion, the dominant basal ganglia to cerebellum ratios of two MRS parameters NAA/Cre and Cho/Cre, and levels of nuclear DNA, mitochondrial DNA, and apoptotic leukocytes were significantly different between PD patients and normal healthy volunteers. Significant positive correlations were noted between MRS measures and inflammatory marker levels. In conclusion, patients with PD seem to have abnormal levels of inflammatory markers in the peripheral circulation and deficits in MRS measures in the dominant basal ganglion and cerebellum.

Plasma Mitochondrial DNA Level is a Prognostic Marker in Peritoneal Dialysis Patients

Background/Aims: Circulating bacterial DNA fragment is related to systemic inflammatory state in peritoneal dialysis (PD) patients. We hypothesize that circulating mitochondrial DNA, which has a similar structure with bacterial DNA, correlates with systemic inflammatory state and predicts cardiovascular event in new PD patients. Methods: We measured plasma mitochondrial DNA level by quantitative polymerase chain reaction (PCR) in 197 new PD patients and 150 patients with chronic kidney disease. PD patients were followed for 24 months for the development of cardiovascular event, hospitalization, and patient survival. Results: There was a stepwise increase in plasma mitochondrial DNA level with worsening renal function. The average plasma mitochondrial DNA level was 18.0 ± 1.2 PCR cycles. Plasma mitochondrial DNA level correlated with serum CRP level (r = -0.538, p < 0.0001). At 24 months, the event-free survival was 67.4%, 66.4%, 63.4% and 44.2% for plasma mitochondrial DNA level quartiles I, II, III and IV, respectively (p = 0.049). After adjusting for confounders, plasma mitochondrial DNA level, malnutrition-inflammation score, and baseline arterial pulse wave velocity were independent predictors of composite cardiovascular end-point; each doubling in plasma mitochondrial DNA level confers 16.0% (95% confidence interval, 2.5 - 31.3%, p = 0.001) excess in risk. Plasma mitochondrial DNA also correlated with the number of hospital admission (r = -0.218, p = 0.002) and duration of hospitalization for cardiovascular reasons (r = -0.232, p = 0.001). Conclusion: Plasma mitochondrial DNA level significantly correlates with systemic inflammatory state, and is a strong predictor of cardiovascular event as well as the need of hospitalization in new PD patients.

Plasma Mitochondrial DNA Levels as a Biomarker of Lipodystrophy Among HIV-infected Patients Treated with Highly Active Antiretroviral Therapy (HAART).

Lipodystrophy is a common complication in HIV-infected patients taking highly active antiretroviral therapy. Its early diagnosis is crucial for timely modification of antiretroviral therapy. We hypothesize that mitochondrial DNA in plasma may be a potential marker of LD in HIV-infected individuals. In this study, we compared plasma mitochondrial DNA levels in HIV-infected individuals and non-HIV-infected individuals to investigate its potential diagnostic value.Total plasma DNA was extracted from 67 HIV-infected patients at baseline and 12, 24 and 30 months after initiating antiretroviral therapy. Real-time quantitative PCR was used to determine the mitochondrial DNA levels in plasma. Lipodystrophy was defined by the physician-assessed presence of lipoatrophy or lipohypertrophy in one or more body regions.The mitochondrial DNA levels in plasma were significantly higher at baseline in HIV-infected individuals than in non-HIV-infected individuals (p<0.05). At month 30, 33 out of 67 patients (49.2%) showed at least one sign of lipodystrophy. The mean plasma mitochondrial DNA levels in lipodystrophy patients were significantly higher compared to those without lipodystrophy at month 24 (p<0.001). The receiver operating curve analysis demonstrated that using plasma mitochondrial DNA level (with cut-off value >5.09 log10 copies/ml) as a molecular marker allowed identification of patients with lipodystrophy with a sensitivity of 64.2% and a specificity of 73.0%.Our data suggest that mitochondrial DNA levels may help to guide therapy selection with regards to HIV lipodystrophy risk.

Variation of perioperative plasma mitochondrial DNA correlate with peak inflammatory cytokines caused by cardiac surgery with cardiopulmonary bypass.

BackgroudCardiac surgery with cardiopulmonary bypass (CPB) may cause inflammatory responses, which can deteriorate the outcomes. Inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6,–8 and -10, can act as both the effector and the predictor for post-operative inflammatory responses. Plasma mitochondrial DNA (mtDNA) was found as a pro-inflammatory agent recently, which was released when cells were insulted.MethodsIn the present study, we included 38 patients undergoing coronary artery bypass graft (CABG) to analyze their perioperative plasma mtDNA and levels of inflammatory cytokines. Blood samples were collected before aortic cross-clamping (T1), at the end of CPB (T2), 6 h post-CPB (T3), 12 h post-CPB (T4), and 24 h post-CPB (T5). Rt-PCR and specific ELISA kits were used to quantify the plasma mtDNA and inflammatory cytokines, respectively. Bivariate correlations analysis was used to check the correlations between plasma mtDNA and inflammatory cytokines respectively.ResultsResults shown that plasma mtDNA elevated significantly at T2 and peaked at T4. Furthermore, plasma TNF-α, IL-6 and IL-8 levels significantly increased at T2 and peaked at T3 while IL-10 elevated and peaked at T2. Bivariate correlations analysis showed that the peak plasma mtDNA were positively correlated with the peak TNF-α (r = 0.677, P < 0.001), the peak IL-6 (r = 0.706, P < 0.001), the peak IL-8 (r = 0.584, P < 0.001) and the peak IL-10 (r = 0.565, P < 0.001).ConclusionWe found that plasma mtDNA might play a key role in CPB-induced post-operative inflammatory responses.

Lengthening and shortening of plasma DNA in hepatocellular carcinoma patients

The analysis of tumor-derived circulating cell-free DNA opens up new possibilities for performing liquid biopsies for the assessment of solid tumors. Although its clinical potential has been increasingly recognized, many aspects of the biological characteristics of tumor-derived cell-free DNA remain unclear. With respect to the size profile of such plasma DNA molecules, a number of studies reported the finding of increased integrity of tumor-derived plasma DNA, whereas others found evidence to suggest that plasma DNA molecules released by tumors might be shorter. Here, we performed a detailed analysis of the size profiles of plasma DNA in 90 patients with hepatocellular carcinoma, 67 with chronic hepatitis B, 36 with hepatitis B-associated cirrhosis, and 32 healthy controls. We used massively parallel sequencing to achieve plasma DNA size measurement at single-base resolution and in a genome-wide manner. Tumor-derived plasma DNA molecules were further identified with the use of chromosome arm-level z-score analysis (CAZA), which facilitated the studying of their specific size profiles. We showed that populations of aberrantly short and long DNA molecules existed in the plasma of patients with hepatocellular carcinoma. The short ones preferentially carried the tumor-associated copy number aberrations. We further showed that there were elevated amounts of plasma mitochondrial DNA in the plasma of hepatocellular carcinoma patients. Such molecules were much shorter than the nuclear DNA in plasma. These results have improved our understanding of the size profile of tumor-derived circulating cell-free DNA and might further enhance our ability to use plasma DNA as a molecular diagnostic tool.

Abstract 3277: A low plasma mitchondrial DNA copy number is associated with increased breast cancer risk

Abstract Previous studies have shown that plasma mtDNA can be separated into two fractions; a supernatant form that is cell-free and a pelleted form that is thought to be platelet associated. These fractions of plasma mtDNA should be measured in studies evaluating the role of plasma mtDNA as biomarkers for early detection or susceptibility to various cancers. Though one case-control study has shown lower plasma mitochondrial DNA (mtDNA) copy number to be associated with increased breast cancer risk this study did not evaluate the two fractions of plasma mtDNA. Hence, the role of plasma mtDNA in determining breast cancer risk was investigated further. We conducted a case-control study of 29 breast cancer cases and 28 cancer free controls to evaluate the association between (a) plasma mtDNA copy number and (b) peripheral blood leucocyte mtDNA copy number and breast cancer risk. Plasma obtained from the breast cancer cases and controls was centrifuged further at 18,000 g for 10 minutes to separate the plasma into the supernatant and pelleted fractions. Using flow cytometry, we stained the pelleted fraction of the plasma with Annexin V and CD61 to determine the cellular source of the plasma pellet. DNA from the two plasma fractions and the buffy coat was extracted using the Qiagen DNAesy DNA extraction kit. Nuclear DNA (18s) and mitochondrial DNA (ND1) copy numbers were measured using quantitative real time PCR. We used a two-sample independent t test to evaluate the difference in mtDNA in the two plasma fractions and mtDNA copy number in peripheral blood leucocytes among breast cancer cases and controls. The plasma pellet fraction predominantly contained particles that were 1-3 microns in size that stained positively for both Annexin V and CD61 indicating that these particles were platelet derived microparticles. The mtDNA in the plasma pellet accounted for 96% of all the plasma mtDNA seen in both cases and controls. Both the plasma supernatant mtDNA (2601034 mtDNA copies/ml of plasma vs. 4700446 mtDNA copies/ml of plasma; p = 0.004) and plasma pellet mtDNA (67787069 mtDNA copies/ml of plasma vs. 112883929 mtDNA copies/ml of plasma; p = 0.001) were significantly lower in the breast cancer cases as compared to controls. Peripheral blood leucocytes mtDNA copy number was not associated with breast cancer risk (4.27 vs. 3.73; p=0.14). There was no correlation between mtDNA in peripheral blood and the various fractions of plasma mtDNA (r= -0.08 - 0.07; p = 0.55 - 0.63). This is the first study to demonstrate platelet derived microparticles as the source of the plasma pellet mtDNA. This study shows that both the supernatant and pelleted fractions of plasma mtDNA are associated with breast cancer risk. Peripheral blood leucocytes mtDNA was not associated with breast cancer risk and was not correlated with plasma mtDNA. Future studies are needed to confirm these associations and evaluate possible mechanisms through which plasma mtDNA copy number is associated with breast cancer risk. Citation Format: Bharat Thyagarajan, Helene Barcelo, Kristin E. Anderson, Karen Swenson, Heather Nelson, Myron D. Gross. A low plasma mitchondrial DNA copy number is associated with increased breast cancer risk. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3277. doi:10.1158/1538-7445.AM2014-3277

Elevated Levels of Plasma Mitochondrial DNA DAMPs Are Linked to Clinical Outcome in Severely Injured Human Subjects

Our objective was to execute a prospective cohort study to determine relationships between plasma mtDNA DAMP levels and the occurrence of systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), and mortality. Mitochondrial DNA damage-associated molecular patterns (DAMPs) accumulate in the circulation after severe injury. Observations in animal models demonstrate that mtDNA DAMPs contribute to organ dysfunction; however, the link between plasma mtDNA DAMPs and outcome in severely injured human subjects has not been established. DNA was isolated from plasma samples taken from severely injured patients at hospital days 0, 1, and 2. Real-time PCR was used to quantify selected ≈200 base pair sequences of mtDNA within the COX1, ND1, and ND6 genes, as well as from the D-Loop transcriptional regulatory region. MODS was defined as a Denver Multiple Organ Failure score of 4 or greater. MtDNA DAMPs were quantified as PCR threshold cycle number. Lower threshold cycles indicate increased mtDNA DAMP content. Patients with SIRS had significantly increased mtDNA DAMP levels in all 4 sequences examined (32.14 ± 0.90 vs 29.00 ± 1.15 for COX1, 31.90 ± 0.47 vs 30.16 ± 1.42 for ND1, 32.40 ± 0.61 vs 28.94 ± 1.13 for ND6, and 33.12 ± 0.83 vs 28.30 ± 1.14 for D-Loop). Patients who developed MODS also had elevated mtDNA DAMP levels compared with those who did not (32.57 ± 0.74 vs 27.12 ± 0.66 for COX1, 32.45 ± 0.65 vs 28.20 ± 0.73 for ND1, 32.52 ± 0.56 vs 27.60 ± 0.79 for ND6, and 32.85 ± 0.75 vs 27.86 ± 1.27 for D-Loop). Patients with above-median mtDNA DAMP levels had a significantly elevated relative risk for mortality. Four patients died secondary to severe MODS. These findings comprise the first observational evidence that plasma mtDNA DAMPs is associated with the evolution of SIRS, MODS, and mortality in severely injured human subjects.

Plasma mitochondrial DNA levels in patients with trauma and severe sepsis: Time course and the association with clinical status

PurposeThis study aimed to investigate the serial changes in plasma levels of mitochondrial DNA (mtDNA) in patients with trauma and severe sepsis and the mechanism of increase in mtDNA levels and the association between the levels and severity. Materials and MethodsWe conducted a prospective observational study of patients with trauma having injuries with an Abbreviated Injury Scale score of 3 or higher (n = 37) and patients with severe sepsis (n = 23). The mtDNA concentrations in clarified plasma were measured using real-time quantitative polymerase chain reaction. ResultsConcentrations of mtDNA peaked on the day of admission (day 1) in patients with trauma, whereas they increased on day 1 and remained constant until day 5 in patients with sepsis. The mtDNA levels on day 1 correlated with the maximal levels of creatinine phosphokinase in patients with trauma (R2 = 0.463, P < .05) but not in patients with sepsis (R2 = 0.028, P = .43). The mtDNA levels on day 1 were significantly higher in nonsurvivors compared with survivors of trauma (P < .05) but not sepsis. ConclusionsThe levels of mtDNA were elevated during traumatic injury and severe sepsis, although time course and prognostic significance differed between the groups, suggesting that the mechanisms of mtDNA release into plasma differ.

Cell-free DNA as a promising marker for risk stratification of pulmonary embolism

Arnalich and colleagues reported an interesting clinical study that evaluated cell-free plasma mitochondrial and nuclear DNA concentrations in patients with pulmonary embolism (PE) [1]. They found increased circulating mitochondrial and nuclear DNA levels, as well as alterations in other cardiac biomarkers (heart-type fatty acidbinding protein and troponin I) in patients with massive PE compared with those found in patients with submassive PE [1]. Importantly, all these biomarkers were found at higher concentrations in fatal massive PE than in nonfatal PE [1]. I would like to add experimental information associating cell-free DNA and acute pulmonary thromboembolism (APT). Experimental evidence showed that cell-free DNA concentrations increase in proportion to the severity of experimental APT [2]. In addition, these previous findings suggest that lysed cells from the thrombi are

Plasma levels of mitochondrial and nuclear DNA in patients with massive pulmonary embolism in the emergency department: a prospective cohort study

IntroductionCell-free plasma mitochondrial DNA (mt-DNA) and nuclear DNA (n-DNA) are biomarkers with prognostic utility in conditions associated with a high rate of cell death. This exploratory study aimed to determine the plasma levels of both nucleic acids in patients with massive and submassive pulmonary embolism (PE) and to compare them with other biomarkers, such as heart-type fatty acid-binding protein (H-FABP) and troponin I (Tn-I)MethodsThis was a prospective observational study of 37 consecutive patients with massive PE, 37 patients with submassive PE, and 37 healthy subjects. Quantifications of plasma mt-DNA and n-DNA with real-time quantitative polymerase chain reaction (PCR), and plasma H-FABP and Tn-I by commercial assays, were done on blood samples drawn within 4 hours after presentation at the emergency department.ResultsPlasma mt-DNA and n-DNA concentrations were much higher in patients with massive PE (median, 2,970 GE/ml; interquartile range (IQR), 1,050 to 5,485; and 3,325 GE/ml, IQR: 1,080 to 5,790, respectively) than in patients with submassive PE (870 GE/ml and 1,245 GE/ml, respectively; P < 0.01) or controls (185 GE/ml and 520 GE/ml, respectively). Eighteen patients with massive PE died of a PE-related cause by day 15 of observation. Plasma mt-DNA and n-DNA values were 2.3-fold and 1.9-fold higher in the subgroup of nonsurviving patients than in survivors. H-FABP and Tn-I values were also higher in patients with massive PE who died (7.3 ng/ml and 0.023 ng/ml, respectively) than in those who survived (6.4 ng/ml, and 0.016 ng/ml, respectively). By receiver operating curve (ROC) analysis, the best cutoff values for predicting 15-day mortality were 3,380 GE/ml for mt-DNA, 6.8 ng/ml for H-FABP, 3,625 GE/ml for n-DNA, and 0.020 ng/ml for Tn-I, based on the calculated areas under the curve (AUCs) of 0.89 (95% confidence interval (CI), 0.78 to 0.99), 0.76 (95% CI, 0.69 to 093), 0.73 (95% CI, 0.58 to 0.91), and 0.59 (95% CI, 0.41 to 0.79), respectively. By stepwise logistic regression, a plasma mt-DNA concentration greater than 3,380 GE/ml (adjusted odds ratio (OR), 8.22; 95% CI, 1.72 to 39.18; P < 0.001) and a plasma value of H-FBAP >6.8 ng/ml (OR, 5.36; 95% CI, 1.06 to 27.08; P < 0.01) were the only independent predictors of mortality.Conclusionsmt-DNA and H-FBAP might be promising markers for predicting 15-day mortality in massive PE, with mt-DNA having better prognostic accuracy.

Lack of Evidence for mtDNA as a Biomarker of Innate Immune Activation in HIV Infection

Many human immunodeficiency virus (HIV) infected individuals suffer from persistent immune activation. Chronic inflammation and immune dysregulation have been associated with an increased risk of age-related diseases even among patients on highly active antiretroviral therapy. The factors leading to immune activation are complex, but have been hypothesized to include persistent viral replication with cellular death as well as microbial translocation across the gastrointestinal tract. Both processes may trigger innate immune responses since many native molecules released from dying cells are similar in structure to pathogen associated molecular patterns. These damage associated molecular patterns include mitochondrial DNA and formylated peptides. We hypothesized that circulating mitochondrial nucleic acid could serve as a biomarker for HIV-associated cell death and drive innate immune activation in infected individuals. We developed a quantitative polymerase chain reaction assay for plasma mitochondrial DNA and validated it on normal blood donors. We then measured mitochondrial DNA levels in acute and chronic HIV infection. While the assay proved to be accurate with a robust dynamic range, we did not find a significant association between HIV disease status and circulating mitochondrial DNA. We did, however, observe a negative correlation between age and plasma mitochondrial DNA levels in individuals with well-controlled HIV.