ccf-mtDNA Levels Research Articles

Plasma circulating cell-free mitochondrial DNA in depressive disorders.

Plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) is an immunogenic molecule and a novel biomarker of psychiatric disorders. Some previous studies reported increased levels of ccf-mtDNA in unmedicated depression and recent suicide attempters, while other studies found unchanged or decreased ccf-mtDNA levels in depression. Inconsistent findings across studies may be explained by small sample sizes and between-study variations in somatic and psychiatric co-morbidity or medication status. We measured plasma ccf-mtDNA in a cohort of 281 patients with depressive disorders and 49 healthy controls. Ninety-three percent of all patients were treated with one or several psychotropic medications. Thirty-six percent had a personality disorder, 13% bipolar disorder. All analyses involving ccf-mtDNA were a priori adjusted for age and sex. Mean levels in ccf-mtDNA were significantly different between patients with a current depressive episode (n = 236), remitted depressive episode (n = 45) and healthy controls (n = 49) (f = 8.3, p<0.001). Post-hoc tests revealed that both patients with current (p<0.001) and remitted (p = 0.002) depression had lower ccf-mtDNA compared to controls. Within the depressed group there was a positive correlation between ccf-mtDNA and "inflammatory depression symptoms" (r = 0.15, p = 0.02). We also found that treatment with mood stabilizers lamotrigine, valproic acid or lithium was associated with lower ccf-mtDNA (f = 8.1, p = 0.005). Decreased plasma ccf-mtDNA in difficult-to-treat depression may be partly explained by concurrent psychotropic medications and co-morbidity. Our findings suggest that ccf-mtDNA may be differentially regulated in different subtypes of depression, and this hypothesis should be pursued in future studies.

Intra-individual state-dependent comparison of plasma mitochondrial DNA copy number and IL-6 levels in patients with bipolar disorder

BackgroundPatients with bipolar disorder (BD) have increased plasma IL-6 levels, which are higher in depressed BD (dBD) than remitted BD (rBD). However, the mechanism that differentiates the cytokine levels between dBD and rBD is not understood. First, we determined whether brain-derived mtDNA can be detected in plasma using neuron-specific mutant Polg1 transgenic (Tg) mice. Second, we investigated whether the plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) differentiate the cytokine levels between dBD and rBD. MethodsMouse plasma ccf-mtDNA levels were measured using real-time PCR targeting two regions of the mtDNA (CO1 and d-loop) in Tg mice and non-Tg littermates. Human plasma ccf-mtDNA levels were measured using real-time PCR targeting two regions of the mtDNA (ND1 and ND4) and IL-6 levels were evaluated in 10 patients in different states (depressed and remitted) of BD in a longitudinal manner and 10 healthy controls. ResultsThe mouse plasma CO1/D-loop ratio was significantly lower in Tg than non-Tg mice (P = 0.0029). Human plasma ccf-mtDNA copy number, ND4/ND1 ratio, and IL-6 levels were not significantly different between dBD and rBD. Human plasma ccf-mtDNA levels showed a nominal significant correlation with delusional symptoms (P = 0.033, ρ = 0.68). LimitationsA larger sample size is required to generalize the results and to determine whether plasma ccf-mtDNA is associated with systemic inflammation. ConclusionsTg mice revealed that brain-derived mtDNA could be present in peripheral blood. The present findings did not coincide with our hypothesis that plasma ccf-mtDNA differentiates the cytokine levels between dBD and rBD.

Circulating Cell-Free Mitochondrial DNA in Cerebrospinal Fluid as a Biomarker for Mitochondrial Diseases.

Mitochondrial diseases (MD) are genetic metabolic disorders that impair normal mitochondrial structure or function. The aim of this study was to investigate the status of circulating cell-free mitochondrial DNA (ccfmtDNA) in cerebrospinal fluid (CSF), together with other biomarkers (growth differentiation factor-15 [GDF-15], alanine, and lactate), in a cohort of 25 patients with a molecular diagnosis of MD. Measurement of ccfmtDNA was performed by using droplet digital PCR. The mean copy number of ccfmtDNA was approximately 6 times higher in the MD cohort compared to the control group; patients with mitochondrial deletion and depletion syndromes (MDD) had the higher levels. We also detected the presence of both wild-type mtDNA and mtDNA deletions in CSF samples of patients with single deletions. Patients with MDD with single deletions had significantly higher concentrations of GDF-15 in CSF than controls, whereas patients with point mutations in mitochondrial DNA presented no statistically significant differences. Additionally, we found a significant positive correlation between ccfmtDNA levels and GDF-15 concentrations (r = 0.59, P = 0.016). CSF ccfmtDNA levels are significantly higher in patients with MD in comparison to controls and, thus, they can be used as a novel biomarker for MD research. Our results could also be valuable to support the clinical outcome assessment of MD patients.

Increased Levels of Circulating Cell-Free mtDNA in the Plasma of Subjects With Late-Life Depression and Frailty: A Preliminary Study

To evaluate the circulating cell-free mitochondrial DNA (ccf-mtDNA) levels, a marker of cellular stress and damage, in older adults with late-life depression (LLD) and frailty. We hypothesize that individuals with both frailty and LLD will have higher ccf-mtDNA levels than individuals with either condition in isolation. Fifty-three older adults (Never Depressed+Robust (reference group, n=16), LLD+Robust (n=9), Never Depressed+Prefrail/Frail (n=5), and LLD+Prefrail/Frail (n=23)) were included in the study. DNA was extracted from EDTA plasma samples, and ccf-mtDNA was quantified by RT-PCR. We found a statistically significant difference in the levels of ccf-mtDNA across groups (F(3,49)=3.07, p=0.036), with individuals in the LLD+Prefrail/Frail group showing the highest levels of ccf-mtDNA. The coexistence of LLD and frailty is associated with increased markers of cellular damage and stress (i.e., ccf-mtDNA). Our results suggest that these conditions may share cellular stress and mitochondrial dysfunction phenomena as a common biological mechanism, offering potential future opportunities for geroscience-guided interventions for these conditions.

Increased levels of circulating cell-free mtDNA in plasma of late life depression subjects

BackgroundOxidative stress (OS) has been implicated in the pathophysiology of late-life depression (LLD). Mitochondria are the primary source of oxidative stress and can be significantly damaged with increased OS. Circulating cell-free mtDNA (ccf-mtDNA) is a marker of cellular stress and mitochondria damage triggered by oxidative stress. MethodsWe evaluated the plasma levels of ccf-mtDNA in between 32 LLD and 21 never-depressed participants. We also investigated the association between ccf-mtDNA and the severity of depressive episodes and cognition performance. ResultsWe found a higher ccf-mtDNA level in LLD cases compared with controls (t = −2.91, p = 0.005). Also, ccf-mtDNA was significantly correlated with the severity of depression (r = 0.42, p = 0.001). There was no significant correlation between ccf-mtDNA and measures of cognitive decline. LimitationsThe small sample size and cross-sectional design were the main limitations of this study. ConclusionOur results suggest that LLD is associated with elevated mitochondrial damage and cellular stress. If validated, the measurement of ccf-mtDNA in LLD can guide the development of novel treatments focused on cytoprotection and reduction of mitochondrial dysfunction for this condition.

Using Circulating Cell-free mtDNA to Examine the Synergetic Effects of Major Depressive Disorder and Frailty

<h3>Introduction</h3> Major depressive disorder (MDD) and frailty are common disorders in elderly populations. These conditions are associated with a higher rate of negative health outcomes and comorbidity. In previous studies, the measurement of circulating cell-free mtDNA (ccf-mtDNA) has been used as biomarkers for cellular stress from increased oxidative stress. No study has yet examined if there are synergistic effects of MDD and frailty in older adults through ccf-mtDNA levels. We hypothesized that individuals diagnosed with both frailty and MDD will have higher ccf-mtDNA levels in comparison to individuals with those conditions in isolation. <h3>Methods</h3> Fifty-three older adults (21 with MDD and 32 controls who were never-depressed) were included in this analysis. Pre-Frail/Frail status was determined by the FRAIL scale. Plasma samples were collected from peripheral blood collections through venipuncture in EDTA tubes. The DNA was extracted from the plasma samples using the QIAmp 96 DNA Blood Kit. The ccf-mtDNA was quantified by RT-PCR. <h3>Results</h3> There were 5 subjects classified as never-depressed and pre-frail/frail. In addition, 23 subjects were identified as depressed and pre-frail/frail. The ccf-mtDNA was significantly higher in those with MDD compared to the control group (p<.01), and in the pre-frail/frail subjects compared to robust older adults (p<.03). We found a significant interaction between MDD and frailty (p=0.03), with the group MDD+pre-frail/frail with the highest levels of ccf-mtDNA. <h3>Conclusions</h3> We found a significant interaction between MDD and frailty increasing the ccf-mtDNA. The higher levels of ccf-mtDNA could indicate worsened cellular stress and mitochondrial dysfunction among those with MDD and Frailty. Our data suggest that frailty and MDD have synergistic effects that increase co-morbidity. Future directions could include increasing the sample size to ensure the validity of the findings. <h3>Funding</h3> Funding was provided by the National Institute of Mental Health (NIMH), USA, and other Canadian funding agencies.

Altered Circulating Cell-free Mitochondrial DNA of Patients with Congenital Scoliosis.

Case-control study. The aim of this study was to estimate the relationship between circulating cell-free DNA (ccf DNA) and clinical parameters of patients with congenital scoliosis (CS). CS is a complex spinal deformity characteristic of congenital vertebral malformations. Although numerous studies have centered on the etiology of CS, the cause of CS remains unclear. Previously, we reported that circulating cell-free DNA (ccf DNA) is altered in adolescent idiopathic scoliosis (AIS). However, the relationship between ccf DNA and the clinical parameters of patients with CS remains unclear. The plasma of peripheral blood from 35 patients with CS and 32 age-matched controls was collected for ccf DNA analysis. Quantitative PCR was used to detect ccf n-DNA and ccf mt-DNA levels, and correlation analyses between ccf n-DNA and ccf mt-DNA levels were conducted. Receiver-operating characteristic (ROC) curves were used to analyze the sensitivity and specificity of ccf n-DNA and ccf mt-DNA levels to different characteristics. The plasma ccf mt-DNA levels of both ND1 and CYTC were significantly decreased in patients with CS compared with levels in controls both in total and by sex, whereas the plasma ccf n-DNA levels showed no significant difference. There is no difference in both ccf mt-DNA and ccf n-DNA between S-SDV and M-SDV according to The International Consortium for Vertebral Anomalies and Scoliosis (ICVAS) classification. The ROC curve analyses showed a reliable sensitivity and specificity of CS predicted by ccf mt-DNA levels in total but failed to distinguish different ICVAS types. Significantly decreased plasma ccf mt-DNA levels were observed in patients with CS compared with those in controls. Although this finding has limited significance for clinical practice, it indicates that ccf mt-DNA may predict the onset or development of CS. Further studies should focus on the role of ccf mt-DNA in embryo development and whether ccf mt-DNAs could be considered as a marker for prenatal screening in development disorder like CS.Level of Evidence: 4.

Evaluation of circulating cell-free nuclear and mitochondrial DNA levels in Syrian patients with breast tumor.

In the last decade, the roles of circulating cell free nuclear (ccfn) and ccf mitochondrial (ccfmt) DNA as potential noninvasive biomarkers have been demonstrated in numerous different types of disease, including cancer. However, the results remain controversial. The present study aimed to investigate the roles of ccfnDNA and ccfmtDNA levels in the plasma of patients with breast cancer. A total of 84 Syrian female subjects were included in the study, who were divided into 3 groups: i) Malignant disease group (n=33); ii) benign disease group (n=26); and iii) healthy control group (n=25). CcfnDNA and ccfmtDNA were determined using real-time quantitative PCR and the reactions were followed by melting curve analysis. The results indicated no significant differences in the plasma levels of ccfnDNA, ccfmtDNA or the ratio of ccfmtDNA/ccfnDNA between the study groups. Of note, a positive correlation was observed between the ccfmtDNA/ccfnDNA ratio and age in the control group (P=0.012; r=0.505). In addition, a positive correlation was identified between ccfnDNA levels and the estrogen receptor status (P=0.045; r=0.416), while a negative correlation between ccfmtDNA/ccfnDNA ratio and the progesterone receptor status was obtained (P=0.045; r=-0.448. Aging and the role of hormones in the cells may be responsible for these results. In the future, the present study should be followed up with mutation detection analyses and large-scale studies.

Circulating cell-free mitochondrial DNA levels correlate with body mass index and age

• These results support that mtDNA release increases with age. • No difference was found between the ccf-mtDNA levels between men and women in each group. • There is a significant correlation between ccf-mtDNA and BMI. • Quantification of ccf-mtDNA in healthy individuals as a possible biomarker of age frailty and metabolic diseases risk

Expanding and validating the biomarkers for mitochondrial diseases

Mitochondrial diseases are highly heterogeneous metabolic disorders caused by genetic alterations in the mitochondrial DNA (mtDNA) or in the nuclear genome. In this study, we investigated a panel of blood biomarkers in a cohort of 123 mitochondrial patients, with prominent neurological and muscular manifestations. These biomarkers included creatine, fibroblast growth factor 21 (FGF21) and growth/differentiation factor 15 (GDF-15), and the novel cell free circulating-mtDNA (ccf-mtDNA). All biomarkers were significantly increased in the patient group. After stratification by the specific phenotypes, ccf-mtDNA was significantly increased in the Mitochondrial Encephalomyopathy Lactic Acidosis Stroke-like episodes syndrome (MELAS) group, and FGF21 and GDF-15 were significantly elevated in patients with MELAS and Myoclonic Epilepsy Ragged Red Fibers syndrome. On the contrary, in our cohort, creatine was not associated to a specific clinical phenotype. Longitudinal assessment in four MELAS patients showed increased levels of ccf-mtDNA in relation to acute events (stroke-like episodes/status epilepticus) or progression of neurodegeneration. Our results confirm the association of FGF21 and GDF-15 with mitochondrial translation defects due to tRNA mutations. Most notably, the novel ccf-mtDNA was strongly associated with MELAS and may be used for monitoring the disease course or to evaluate the efficacy of therapies, especially in the acute phase.Key messages• FGF21/GDF15 efficiently identifies mitochondrial diseases due to mutations in tRNA genes.• The novel ccf-mtDNA is associated with MELAS and increases during acute events.• Creatine only discriminates severe mitochondrial patients.• FGF21, GDF-15, and ccf-mtDNA are possibly useful for monitoring therapy efficacy.

Pro-inflammatory role of cell-free mitochondrial DNA in cardiovascular diseases.

Cardiovascular disease (CVD) is a major cause of morbidity and mortality. Inflammation contributes to the pathogenesis and progression of CVD. Circulating cell-free mitochondrial DNA (ccf-mtDNA) is that mtDNA fragments are released outside the cell and into the circulation by cell necrosis and secretion. The levels of ccf-mtDNA are increased in CVD and associated risk conditions, including hypercholesterolemia, diabetes mellitus, and arterial hypertension. MtDNA containing unmethylated CpG dinucleotides and can trigger inflammation that aggravates tissue injury by activating toll-like receptor 9, inflammasomes, and the stimulator of interferon genes pathway. Here, we review the expanding field of ccf-mtDNA-mediated inflammation and its role in the progression of CVD.

Massive Release of CD9+ Microvesicles in Human Immunodeficiency Virus Infection, Regardless of Virologic Control.

BackgroundThe role of extracellular vesicles (EVs) in human immunodeficiency virus (HIV) pathogenesis is unknown. We examine the cellular origin of plasma microvesicles (MVs), a type of ectocytosis-derived EV, the presence of mitochondria in MVs, and their relationship to circulating cell-free mitochondrial deoxyribonucleic acid (ccf-mtDNA) in HIV-infected patients and controls.MethodsFive participant groups were defined: 30 antiretroviral therapy (ART)-naive; 30 ART-treated with nondetectable viremia; 30 elite controllers; 30 viremic controllers; and 30 HIV-uninfected controls. Microvesicles were quantified and characterized from plasma samples by flow cytometry. MitoTrackerDeepRed identified MVs containing mitochondria and ccf-mtDNA was quantified by real-time polymerase chain reaction.ResultsMicrovesicle numbers were expanded at least 10-fold in all HIV-infected groups compared with controls. More than 79% were platelet-derived MVs. Proportions of MVs containing mitochondria (22.3% vs 41.6%) and MV mitochondrial density (706 vs 1346) were significantly lower among HIV-infected subjects than controls, lowest levels for those on ART. Microvesicle numbers correlated with ccf-mtDNA levels that were higher among HIV-infected patients.ConclusionsA massive release of platelet-derived MVs occurs during HIV infection. Some MVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls. Platelet-derived MVs may be biomarkers of platelet activation, possibly reflecting pathogenesis even in absence of HIV replication.

Dietary Supplementation of Gingerols- and Shogaols-Enriched Ginger Root Extracts Attenuate Pain-Associated Behaviors in Animals with Spinal Nerve Ligation

Abstract Objectives Neuropathic pain (NP), arising from damage to the nervous system, could be a consequence of the imbalance between reactive oxygen species (ROS) and endogenous antioxidants after nerve injury, leading to neuroinflammation. Therefore, this study was to evaluate the effects of two ginger root extracts rich in gingerols and shogoals, respectively, on pain sensitivity and anxiety-like behaviors in neuropathic animals. We also assessed the plasma circulating cell-free mitochondrial DNA (ccf-mtDNA) damage, a biomarker of excessive mitochondria-derived ROS linked to inflammation. Methods Sixteen male rats were randomly divided into 4 groups: sham group, spinal nerve ligation (SNL) group as the pain control group, SNL+ gingerols-enriched ginger (GEG) extract group, and SNL+ shogoals-enriched ginger (SEG) extract group. Animals in GEG and SEG groups were fed with their respective diets on the day of SNL surgery for 30 days. At 1 day before and 10, 20, and 30 days post operation, (i) paw withdrawal mechanical thresholds were measured using von Frey filaments for pain sensory assessment; and (ii) center frequency and center duration in the open field test (OFT) were measured to assess anxiety-like behavior. At Day 30, plasma was obtained for ccf-mtDNA concentration measurement. Data were analyzed by one-way ANOVA or one-way repeated measures analysis of variance follow by post-hoc analysis. Results Compared to the sham group, the SNL group had significant greater pain sensitivity to mechanical stimuli. When compared to the SNL group, both GEG and SEG groups showed significantly (50%) reduced pain sensitivity (increased thresholds) as early as at 10 days and sustained at 30 days. Relative to the SNL group, both GEG and SEG groups also had less anxiety-like behavior (as indicated by the elongated center duration and increased center frequency in OFT). The SNL group had significantly higher plasma ccf-mtDNA levels relative to the sham group. When SNL-animals were fed a diet supplemented with either gingerols or shogaols, both groups showed reduction in plasma ccf-mtDNA. Conclusions Both gingerols and shogaols supplementation decreased pain sensitivity and improved anxiety-like behavior mediated in part through the suppression of mitochondrial damage. Funding Sources Texas Tech University Health Sciences Center.

Peripheral biomarkers of mitochondrial dysfunction in adolescents with bipolar disorder

BackgroundMitochondrial dysfunction has been implicated in the pathophysiology of bipolar disorder (BD). Impediment of mitochondrial oxidative phosphorylation results in a shift toward anaerobic respiration and lactate production. Elevated CNS lactate levels in adults with BD inform the need to evaluate lactate in peripheral samples and early in the course of BD. Furthermore, there exists a recent surge of investigations looking at circulating cell-free mitochondrial DNA (ccf-mtDNA) as a potential biomarker as they are released from cells under physiological stress, apoptosis, or bioenergetic compromise. ObjectivesTo compare lactate and ccf-mtDNA, two different ways in assessing the mitochondrial health and function, in adolescents with BD versus healthy control adolescents (HC). MethodsOne-hundred and five adolescents (n = 64 BD, n = 41 HC) were included. Serum lactate level was measured using a commercially available colorimetric kit. Serum ccf-mtDNA concentration was measured using quantitative polymerase chain reaction from ccfDNA purified by commercially available spin columns. Diagnosis and mood symptoms were evaluated using semi-structured interviews. ResultsThere is an increase in serum lactate level of adolescents with BD (1.319 ± 0.444 nmol/uL) versus HC (1.168 ± 0.353 nmol/uL; p = 0.043), but not ccf-mtDNA. Among BD adolescents, depression symptoms were negatively correlated with ccf-mtDNA levels (ρ = −0.289; p = 0.038) but loses significance when corrected for multiple comparison. Lactate was positively correlated with ccf-mtDNA in the overall sample (ρ = 0.201; p = 0.043). When examined by diagnosis, this association remained in BD (ρ = 0.273; p = 0.032), but not HC. ConclusionThese preliminary results indicate that elevated lactate is observed even among adolescents early in their course of BD, that the association between lactate and ccf-mtDNA appears to be specific to BD, and that ccf-mtDNA is potentially associated with depression symptoms in adolescent BD. In addition, the effect of psychotropic medications used in the treatment of BD on peripheral lactate and ccf-mtDNA requires further investigation.

Changes in circulating cell-free nuclear DNA and mitochondrial DNA of patients with adolescent idiopathic scoliosis

BackgroundAdolescent idiopathic scoliosis (AIS) which characterized by complex three-dimensional deformity of spine has been difficult to cure because of the unknown etiopathology and uncertainty of progression. Nowadays, circulating cell-free (ccf) DNA was found to be a potential biomarker for several benign and malignant diseases. However, whether ccf DNA can be a biomarker for AIS has not been reported yet. In this study, we investigate the circulating cell-free nuclear DNA (ccf n-DNA) and mitochondrial DNA (ccf mt-DNA) concentrations in the plasma of patients with AIS and controls (CT), and the changed plasma ccf n-DNA and ccf mt-DNA levels and their association with clinical parameters were assessed.MethodsThe plasma of peripheral blood from 69 AIS patients and 21 age-matched CT was collected for ccf DNA analysis. Quantitative PCR was used to detect ccf n-DNA and ccf mt-DNA levels, and correlation analyses between the ccf n-DNA and ccf mt-DNA levels and clinical characteristics were conducted. Receiver operator curves (ROC) were used to analyze the sensitivity and specificity of ccf n-DNA and ccf mt-DNA levels to different characteristics.ResultsThe plasma ccf n-DNA levels of both GAPDH and ACTB were significantly decreased in AIS patients compared with those in controls, while the plasma ccf mt-DNA levels did not changed. According to sex-related analyses, the ccf n-DNA levels in male CT-M was higher than that in female CT and male AIS, but the ccf n-DNA levels in female AIS was not significantly changed when compared with male AIS or female CT. However, the concentration of ccf mt-DNA in female AIS increased significantly when compared with male AIS. Surprisingly, Lenke type-related analyses suggested that Lenke type 1 patients had lower ccf n-DNA levels, whereas Lenke type 5 patients had higher ccf mt-DNA levels compared with those of controls. However, a lower sensitivity and specificity of AIS predicted by ccf n-DNA or ccf mt-DNA levels was observed, whether in total, by sex, or by Lenke type.ConclusionAlthough with no/little predictive accuracy of AIS/progressed AIS by ccf DNA levels, significantly changed plasma ccf DNA levels were observed in AIS patients compared with those in controls.

Circulating Mitochondrial DNA is Linked to Progression and Prognosis of Epithelial Ovarian Cancer

As peripheral blood contains fluctuated levels of circulating cell-free mitochondrial DNA (ccf mtDNA), we aimed to evaluate ccf mtDNA as a biomarker for diagnosis and prognosis of epithelial ovarian cancer (EOC). In the present study, we recruited 165 EOC patients and 60 healthy women. Quantitative RT-PCR was applied to amplify 79-bp and 230-bp fragments of the mitochondrial 16 s RNA gene in sera of these participants. MtDNA integrity was defined as the ratio of long to short mtDNA fragments. We observed that the levels of mtDNA79 and mtDNA230 were significantly increased (P = .0001), whereas the mtDNA integrity (P = .0001) was decreased in EOC patients compared with those in healthy controls. MtDNA79 showed a sensitivity of 90.3% and a specificity of 81.7% (AUC = 0.900) to discriminate EOC from healthy controls. Moreover, the amounts of mtDNA79 (P = .0001, P = .012, P = .039) and mtDNA230 (P = .0001, P = .042) continuously raised from healthy controls over FIGO I-II to FIGO III and IV, with highest levels of mtDNA79 (P = .0001) and mtDNA230 (P = .0001) in FIGO III and IV. Increasing levels of mtDNA79 (P = .003, P = .0001) and mtDNA230 (P = .041, P = .0001) were also associated with lymph node metastasis and CA125 values. The higher levels of mtDNA79 (P = .0001; HR 3.2, 95%CI:1.6–6.3) and mtDNA230 (borderline P = .048, HR 0.9, 95%CI:0.9–1.0) also correlated with poor patients' overall survival, of which mtDNA79 could act as an independent factor for overall survival. Our data show a significant association of increasing levels of ccf mtDNA with EOC progress and poor prognosis.

Ccf-mtDNA as a Potential Link Between the Brain and Immune System in Neuro-Immunological Disorders.

Fragments of mitochondrial DNA (mtDNA) are released outside the cell and they appear to persist in extracellular fluids as circulating, cell-free, mtDNA (ccf-mtDNA). When compared to nuclear DNA, such a double stranded mtDNA is more resistant to nuclease degradation. In fact, it is stable extracellularly where it can be detected in both plasma and cerebrospinal fluid (CSF), here acting as a potential biomarker in various disorders. In neurological diseases (Alzheimer's disease, Parkinson's disease and end-stage progressive Multiple Sclerosis), a decreased amount of CSF ccf-mtDNA is related with progressive cell dysfunction. This suggests an alteration in neuronal mtDNA levels (mtDNA replication, degradation and depletion) in vulnerable brain regions at early stages of neurodegeneration leading to reduced mtDNA release, which takes place before actual cell death occurs. On the other hand, elevated CSF ccf-mtDNA levels are reported in acute phases of relapsing-remitting Multiple Sclerosis (RRMS). This occurs during acute inflammation, which anticipates the neurodegenerative process. Thus, an increase in inflammatory cells in the affected regions is expected to add on mtDNA release into the CSF. In addition, similarly to bacterial DNA, the non-methylated CpG sites of mtDNA, which activate innate immunity and inflammation, are likely to participate in the molecular mechanisms of disease. Thus, ccf-mtDNA may represent a powerful biomarker for disease screening and prognosis at early stage, although its biological role may extend to generating the neurobiology of disease. The present manuscript discusses recent experimental findings in relationship with clinical evidence comparing neuro-immunological features of neurodegenerative disorders with frankly neuro-infectious diseases.

Circulating Cell-Free mtDNA Contributes to AIM2 Inflammasome-Mediated Chronic Inflammation in Patients with Type 2 Diabetes.

Mitochondrial dysfunction has been implicated in the pathogenesis of insulin resistance and type 2 diabetes. Damaged mitochondria DNA (mtDNA) may have a role in regulating hyperglycemia during type 2 diabetes. Circulating cell-free mitochondria DNA (ccf-mtDNA) was found in serum and plasma from patients and has been linked to the prognosis factors in various human diseases. However, the role of ccf-mtDNA in chronic inflammation in type 2 diabetes is unclear. In this study, we hypothesized that the ccf-mtDNA levels are associated with chronic inflammation in patients with type 2 diabetes. The mtDNA levels were elevated in the plasma from patients with type 2 diabetes compared to healthy subjects. The elevated mtDNA levels were associated with interleukin-1β (IL-1β) levels in patients with type 2 diabetes. The mtDNA, from patients with type 2 diabetes, induced absent in melanoma 2 (AIM2) inflammasome-dependent caspase-1 activation and IL-1β and IL-18 secretion in macrophages. Our results suggest that the ccf-mtDNA might contribute to AIM2 inflammasome-mediated chronic inflammation in type 2 diabetes.

Inevitable isolation and the change of stress markers in hemodialysis patients during the 2015 MERS-CoV outbreak in Korea

During the outbreak of Middle East respiratory syndrome coronavirus(MERS-CoV) in 2015, one hemodialysis patient was infected with MERS-CoV, and the remaining hemodialysis(HD) patients (n = 83) and medical staff (n = 12) had to undergo dialysis treatment in an isolated environment. This study was performed to investigate the effects of stress caused by dialysis treatment under isolation. Plasma samples from the HD patients and medical staff were collected at the time of isolation(M0), the following month(M1), and three months after isolation(M3). Parameters for stress included circulating cell-free genomic DNA(ccf-gDNA), circulating cell-free mitochondria DNA(ccf-mtDNA), and pentraxin-3(PTX-3). Decreased values of Hct, kt/v and ca x p were recovered after the end of two weeks of isolation. The levels of ccf-gDNA and ccf-mtDNA were the highest at M0 and decreased gradually in both HD patients and the medical staff. The normalization of ccf-gDNA and ccf-mtDNA was significantly delayed in HD patients compared with the response in the medical staff. PTX-3 increased only in HD patients and was highest at M0, and it then gradually decreased. Medical isolation and subnormal quality of care during the MERS outbreak caused extreme stress in HD patients. Plasma cell-free DNA and PTX-3 seems to be good indicators of stress and quality of care in HD patients.

Acute psychological stress increases serum circulating cell-free mitochondrial DNA

Intrinsic biological mechanisms transduce psychological stress into physiological adaptation that requires energy, but the role of mitochondria and mitochondrial DNA (mtDNA) in this process has not been defined in humans. Here, we show that similar to physical injury, exposure to psychological stress increases serum circulating cell-free mtDNA (ccf-mtDNA) levels. Healthy midlife adults exposed on two separate occasions to a brief psychological challenge exhibited a 2-3-fold increase in ccf-mtDNA, with no change in ccf-nuclear DNA levels, establishing the magnitude and specificity for ccf-mtDNA reactivity. In cell-based studies, we show that glucocorticoid signaling – a consequence of psychological stress in humans – is sufficient to induce mtDNA extrusion in a time frame consistent with stress-induced ccf-mtDNA increase. Collectively, these findings provide evidence that acute psychological stress induces ccf-mtDNA and implicate neuroendocrine signaling as a potential trigger for ccf-mtDNA release. Further controlled work is needed to confirm that observed increases in ccf-mtDNA result from stress exposure and to determine the functional significance of this effect.