Impact of cerebral collateral flow on stroke outcomes after carotid stenting.

OBJECTIVE: Internal carotid artery stenosis is a main contributor to recurrent ischemic stroke. This study aimed to evaluate associations between recurrent stroke and changes in prestenting flow direction in the primary collaterals or both primary and secondary collaterals, and the potential interaction between extra- and intracranial arteries. METHODS: This longitudinal study recruited stroke patients without intracranial stenosis who underwent right-side carotid stenting between 2011 and 2019. The main study outcome was recurrent stroke. Predictive factors were anterior circulation flow direction change (ACFDC), posterior circulation flow direction change, and reversal of ophthalmic artery/leptomeningeal anastomosis (ROALA) detected by transcranial color-coded duplex (TCCD) before carotid stenting. Patient follow-up was 9 years. Risk factors for recurrent stroke were identified by Kaplan-Meier plot and Cox regression analyses. RESULTS: A total of 234 patients (mean age 70.88 ± 10.3 years, 86.32% male) were included, and 115 had recurrent stroke. Kaplan-Meier plot showed that patients with left ACFDC and ROALA had worse outcomes than those with ACFDC only, while patients with left ACFDC had worse outcome than those with right ACFDC (both p < 0.001). Cox regression analysis showed that recurrent stoke was associated with ACFDC at right (hazard ratio [95% CI]: 20.988 [2.549-172.790], p < 0.01), left (151.441 [20.100-1140.993], p < 0.001), and both sides (144.889 [19.089-1099.710], p < 0.001). INTERPRETATION: Anterior circulation flow direction change is significantly associated with recurrent stroke in patients with unilateral carotid stenosis. Patients with ACFDC and ROALA together have worse outcomes compared to those with ACFDC only. Prestenting TCCD images help provide definitive information to predict outcomes after carotid stenting.

Ophthalmic artery flow direction change predicts recurrence of ischemic stroke after carotid stenting: a longitudinal observational study.

BACKGROUND AND PURPOSE: The implantation of carotid artery stents prevents recurrent ischemic stroke in patients with carotid stenosis. This study aimed to investigate associations between change of ophthalmic artery flow (COAF) post carotid stenting and recurrent ischemic stroke, as well as the link toward the anterior and posterior circulations and patients' prognosis after carotid stenting. METHODS: This retrospective, longitudinal cohort study recruited 87 left side carotid stenosed ischemic stroke patients undergoing left side carotid stenting between year of 2009 and 2013, and patients were followed up to 9 years after carotid procedures. Clinical data were derived from medical records. The primary outcome was stroke recurrence. Predictive factors were stenosis > 50% in one intracranial artery and ROAF. Kaplan-Meier and Cox regression analyses were used to identify risk factors associated with stroke recurrence. RESULTS: Among 87 included patients undergone left side carotid stent treatment, 44 had stroke recurrence within 3 years after carotid stenting. The recurrence group had significantly greater proportions of COAF after stenting (p = 0.001), and middle cerebral artery (MCA) and basilar artery or vertebral artery (BA/VA) stenosis > 50% (all p < 0.001) than the no-recurrence group. Survival was significantly shorter in patients with COAF than in those without (p < 0.01). Regression analysis showed that COAF was associated with stroke recurrence (HR: 3.638, 95% CI 1.54-8.62, p = 0.003). The recurrence rate was highest in patients with bilateral MCA stenosis > 50% (100%), followed by left MCA stenosis > 50% plus BA/VA stenosis > 50% (83.33%) or COAF (82.14%). Patients with bilateral MCA stenosis < 50% had no recurrence within 3-year follow-up. CONCLUSIONS: Prognosis after carotid stenting is poorer for patients with MCA stenosis > 50%, BA/VA stenosis > 50% and/or COAF. Carotid duplex and magnetic resonance angiography provide definitive information for prognosis prediction.

Association of leukocyte mitochondrial DNA copy number with longitudinal C-reactive protein levels and survival in older adults: a cohort study.

BACKGROUND: Systemic chronic inflammation occurs with age. The association of the leukocyte mitochondrial DNA copy number, a measure of mitochondrial function in aging, with the temporal profile of serum high-sensitivity C-reactive protein and mortality risk remains uncertain. The objectives of this study were to examine the association of the leukocyte mitochondrial DNA copy number with longitudinal high-sensitivity C-reactive protein levels and the association of the longitudinal high-sensitivity C-reactive protein levels with mortality risk. METHODS: This prospective cohort study included 3928 adults aged ≥ 55 years without systemic inflammation in the baseline examination of the Healthy Aging Longitudinal Study in Taiwan, which started in 2009. Each participant received leukocyte mitochondrial DNA copy number measurement using a fluorescence-based quantitative polymerase chain reaction at baseline, serum high-sensitivity C-reactive protein measurements at baseline and the follow-up examination five years later, and the ascertainment of all-cause death (until November 30, 2021). The relationships among the leukocyte mitochondrial DNA copy number, longitudinal serum high-sensitivity C-reactive protein levels, and time to all-cause mortality were examined using the joint longitudinal and survival modeling analysis. RESULTS: Of the 3928 participants (mean age: 69 years; 2060 [52%] were women), 837 (21%) died during follow-up. In the adjusted analysis, one standard deviation lower natural log-transformed baseline leukocyte mitochondrial DNA copy number was associated with an increase of 0.05 (95% confidence interval [CI], 0.02 to 0.08) standard deviation in serum high-sensitivity C-reactive protein in subsequent years. An increase of 1 standard deviation in instantaneous high-sensitivity C-reactive protein levels was associated with a hazard ratio (HR) for all-cause mortality of 1.22 (95% CI, 1.14 to 1.30). Similar results were obtained after further adjusting for baseline high-sensitivity C-reactive protein levels (HR [95% CI], 1.27 [1.16 to 1.38]) and after excluding those with serum high-sensitivity C-reactive protein above 10 mg/L (HR [95% CI], 1.21[1.11 to 1.31]) or 3 mg/L (HR [95% CI], 1.19 [1.06 to 1.31]) during follow-up. CONCLUSIONS: A lower leukocyte mitochondrial DNA copy number was associated with persistently higher high-sensitivity C-reactive protein levels. Moreover, these higher time-varying high-sensitivity C-reactive protein levels were instantaneously associated with a higher risk of death.

Regulation of mitochondrial fusion and mitophagy by intra-tumoral delivery of membrane-fused mitochondria or Midiv-1 enhances sensitivity to doxorubicin in triple-negative breast cancer.

Increasing mitochondrial fusion by intra-tumoral grafting of membrane-fused mitochondria created with Pep-1 conjugation (P-Mito) contributes to breast cancer treatment, but it needs to be validated. Using mitochondrial division inhibitor-1 (Mdivi-1, Mdi) to disturb mitochondrial dynamics, we showed that the antitumor action of P-Mito in a mouse model of triple-negative breast cancer depends upon mitochondrial fusion and that Mdi treatment alone is ineffective. P-Mito significantly enhanced Doxorubicin (Dox) sensitivity by inducing mitochondrial fusion and mitophagy, and the same efficiency was also achieved with Mdi by inhibiting mitophagy. Cell death was induced via the p53 pathway and AIF nuclear translocation in the case of P-Mito, versus the caspase-dependent pathway for Mdi. Notably, both mitochondrial treatments reduced oxidative stress and blood vessel density of xenograft tumors, especially P-Mito, which was accompanied by inhibition of nuclear factor kappa-B activation. Furthermore, through enrichment analysis, four microRNAs in serum microvesicles induced by P-Mito caused expression of predicted targets via the PI3K-Akt pathway, and significantly impacted regulation of nuclear processes and myeloid cell differentiation. Clustering of gene-sets implicated a major steroid catabolic network. This study showed diverse roles of mitochondria in breast cancer and revealed effective adjuvant therapy targeting mitochondrial fusion and mitophagy.

IGF-1 as a Potential Therapy for Spinocerebellar Ataxia Type 3.

Although the effects of growth hormone (GH) therapy on spinocerebellar ataxia type 3 (SCA3) have been examined in transgenic SCA3 mice, it still poses a nonnegligible risk of cancer when used for a long term. This study investigated the efficacy of IGF-1, a downstream mediator of GH, in vivo for SCA3 treatment. IGF-1 (50 mg/kg) or saline, once a week, was intraperitoneally injected to SCA3 84Q transgenic mice harboring a human ATXN3 gene with a pathogenic expanded 84 cytosine-adenine-guanine (CAG) repeat motif at 9 months of age. Compared with the control mice harboring a 15 CAG repeat motif, the SCA3 84Q mice treated with IGF-1 for 9 months exhibited the improvement only in locomotor function and minimized degeneration of the cerebellar cortex as indicated by the survival of more Purkinje cells with a more favorable mitochondrial function along with a decrease in oxidative stress caused by DNA damage. These findings could be attributable to the inhibition of mitochondrial fission, resulting in mitochondrial fusion, and decreased immunofluorescence staining in aggresome formation and ataxin-3 mutant protein levels, possibly through the enhancement of autophagy. The findings of this study show the therapeutic potential effect of IGF-1 injection for SCA3 to prevent the exacerbation of disease progress.

Mitochondrial DNA Copy Number Is Associated With Treatment Response and Cognitive Function in Euthymic Bipolar Patients Receiving Valproate.

BACKGROUND: Bipolar disorder (BD) is associated with cognitive impairment and mitochondrial dysfunction. However, the associations among mitochondrial DNA copy number (MCN), treatment response, and cognitive function remain elusive in BD patients. METHODS: Sixty euthymic BD patients receiving valproate (VPA) and 66 healthy controls from the community were recruited. The indices of metabolic syndrome (MetS) were measured. Quantitative polymerase chain reaction analysis of blood leukocytes was used to measure the MCN. Cognitive function was measured by calculating perseverative errors and completed categories on the Wisconsin Card Sorting Test (WCST). The VPA treatment response was measured using the Alda scale. RESULTS: BD patients had significantly higher MCN, triglyceride, and C-reactive protein (CRP) levels, waist circumference, and worse performance on the WCST than the controls. Regression models showed that BD itself and the VPA concentration exerted significant effects on increased MCN levels. Moreover, the receiver operating characteristic curve analysis showed that an MCN of 2.05 distinguished VPA responders from nonresponders, with an area under the curve of 0.705 and a sensitivity and specificity of 0.529 and 0.816, respectively. An MCN level ≥2.05 was associated with 5.39 higher odds of being a VPA responder (P = .006). BD patients who were stratified into the high-MCN group had a higher VPA response rate, better WCST performance, lower CRP level, and less MetS. CONCLUSIONS: The study suggests a link between the peripheral MCN and cognitive function in BD patients. As an inflammatory status, MetS might modulate this association.

Intranasal delivery of mitochondria for treatment of Parkinson's Disease model rats lesioned with 6-hydroxydopamine.

The feasibility of delivering mitochondria intranasally so as to bypass the blood-brain barrier in treating Parkinson's disease (PD), was evaluated in unilaterally 6-OHDA-lesioned rats. Intranasal infusion of allogeneic mitochondria conjugated with Pep-1 (P-Mito) or unconjugated (Mito) was performed once a week on the ipsilateral sides of lesioned brains for three months. A significant improvement of rotational and locomotor behaviors in PD rats was observed in both mitochondrial groups, compared to sham or Pep-1-only groups. Dopaminergic (DA) neuron survival and recovery > 60% occurred in lesions of the substantia nigra (SN) and striatum in Mito and P-Mito rats. The treatment effect was stronger in the P-Mito group than the Mito group, but the difference was insignificant. This recovery was associated with restoration of mitochondrial function and attenuation of oxidative damage in lesioned SN. Notably, P-Mito suppressed plasma levels of inflammatory cytokines. Mitochondria penetrated the accessory olfactory bulb and doublecortin-positive neurons of the rostral migratory stream (RMS) on the ipsilateral sides of lesions and were expressed in striatal, but not SN DA neurons, of both cerebral hemispheres, evidently via commissural fibers. This study shows promise for intranasal delivery of mitochondria, confirming mitochondrial internalization and migration via RMS neurons in the olfactory bulb for PD therapy.

Antitumor Actions of Intratumoral Delivery of Membrane-Fused Mitochondria in a Mouse Model of Triple-Negative Breast Cancers.

BACKGROUND: The transfer of whole mitochondria has been demonstrated to be beneficial for treating breast cancer because it induces apoptosis and drug sensitivity; however, in vivo evidence of this benefit remains scant. The present study compared the transplantation of mitochondria with instinctive (Mito) and membrane-fused morphologies induced by Pep-1 conjugation (P-Mito) using a mouse model of triple-negative breast cancers. MATERIALS AND METHODS: Mice with advanced severe immunodeficiency received orthotopic implantation of MDA-MB-231 human breast cancer cells followed by transplants of 5-bromo-2'-deoxyuridine (BrdU)-labeled Mito or P-Mito (200 µg [10 µg/µL]) through intratumoral injection at multiple points once a week for 4 weeks. RESULTS: After 1 month of consecutive treatment, 8.2% and 14.2% of the BrdU-labeled mitochondria were preserved in tumors of the Mito and P-Mito groups, respectively. Both Pep-1 and P-Mito treatments reduced tumor weight (21.7% ± 2.43% vs 40.6% ± 2.28%) and led to marked inhibition of Ki67 staining and angiogenesis. However, only the P-Mito group exhibited obvious necrosis and DNA fragmentation accompanied by an altered tumor microenvironment, which included reduced oxidative stress and size of cancer-associated fibroblast populations and enhanced immune cell infiltration. Transmission electron microscopy images further revealed an elongated network of perinuclear mitochondria fused with a few peripheral mitochondria in the nonnecrotic area in the P-Mito group as well as increases in mitochondrial fusion proteins and parkin compared with mitochondrial fission proteins. CONCLUSION: In this study, the results of mitochondrial transplantation emphasized that the facilitation of mitochondrial fusion is a critical regulator in breast cancer therapy.

Treadmill training increases the motor activity and neuron survival of the cerebellum in a mouse model of spinocerebellar ataxia type 1.

Spinocerebellar ataxia (SCA) type 1 (SCA1) is a rare autosomal dominant disorder that is characterized by worsening of disordered coordination, ataxia of the trunk, and other neurological symptoms. Physical activity improves both mobility and the daily living activities of patients with SCA. Intervention with daily regular treadmill exercise may slow the deterioration of cerebellar neurons in SCA1. Therefore, the signal changes and performance of cerebellar neurons after exercise in SCA1 was investigated in this study. We employed a transgenic mouse model of SCA1, generated by amplifying the cytosine-adenine-guanine trinucleotide repeat expansions, and the mice underwent 1 month of moderate daily treadmill exercise for 1 hour. The rotarod test revealed that the motor function of the SCA1 mice that underwent training was superior to that of the control SCA1 mice, which did not undergo training. Moreover, the cerebellar pathology revealed preserved Purkinje neurons stained by carbindin with an increase of the neuronal Per Arnt Sim domain protein 4, a key regulation in the structural and functional plasticity of neurons, in the excised SCA1 mice relative to the controls. The mechanism was related to an increase of phosphorylation of ribosomal protein S6, a downstream target of the mammalian target of rapamycin pathway, but not to autophagy activation. This study determined that regular treadmill exercise may play a crucial role in the viable support of cerebellar neurons in SCA1.

Mitochondrial transplantation regulates antitumour activity, chemoresistance and mitochondrial dynamics in breast cancer.

BACKGROUND: The transfer of whole mitochondria that occurs during cell contact has been found to support cancer progression. However, the regulatory role of mitochondria alone is difficult to elucidate due to the complex microenvironment. Currently, mitochondrial transplantation is an available approach for restoring mitochondrial function in mitochondrial diseases but remains unclear in breast cancer. Herein, effects of mitochondrial transplantation via different approaches in breast cancer were investigated. METHODS: Whole mitochondria (approximately 10.5 µg/ml) were transported into MCF-7 breast cancer cells via passive uptake or Pep-1-mediated delivery. Fresh mitochondria isolated from homeoplasmic 143B osteosarcoma cybrids containing mitochondrial DNA (mtDNA) derived from health individuals (Mito) or mtDNA with the A8344G mutation (Mito8344) were conjugated with cell-penetrating peptide Pep-1 (P-Mito) or not conjugated prior to cell co-culture. Before isolation, mitochondria were stained with MitoTracker dye as the tracking label. After 3 days of treatment, cell viability, proliferation, oxidative stress, drug sensitivity to Doxorubicin/Paclitaxel and mitochondrial function were assessed. RESULTS: Compared with P-Mito, a small portion of Mito adhered to the cell membrane, and this was accompanied by a slightly lower fluorescent signal by foreign mitochondria in MCF-7 cells. Both transplantations induced cell apoptosis by increasing the nuclear translocation of apoptosis-inducing factor; inhibited cell growth and decreased oxidative stress in MCF-7 cells; and increased the cellular susceptibility of both the MCF-7 and MDA-MB-231 cell lines to Doxorubicin and Paclitaxel. Mitochondrial transplantation also consistently decreased Drp-1, which resulted in an enhancement of the tubular mitochondrial network, but a distinct machinery through the increase of parkin and mitochondrial fusion proteins was observed in the Mito and P-Mito groups, respectively. Furthermore, although there were no differences in energy metabolism after transplantation of normal mitochondria, metabolism was switched to the energetic and glycolytic phenotypes when the mitochondria were replaced with dysfunctional mitochondria, namely, Mito8344 and P-Mito8344, due to dramatically induced glycolysis and reduced mitochondrial respiration, respectively. Consequently, transplant-induced growth inhibition was abolished, and cell growth in the Mito8344 group was even higher than that in the control group. CONCLUSION: This study reveals the antitumour potential of mitochondrial transplantation in breast cancer via distinct regulation of mitochondrial function.

Far-infrared Radiation Improves Motor Dysfunction and Neuropathology in Spinocerebellar Ataxia Type 3 Mice.

Spinocerebellar ataxia type 3 (SCA3) is a polyglutamine neurodegenerative disease resulting from the misfolding and accumulation of a pathogenic protein, causing cerebellar dysfunction, and this disease currently has no effective treatments. Far-infrared radiation (FIR) has been found to protect the viability of SCA3 cells by preventing mutant ataxin-3 protein aggregation and promoting autophagy. However, this possible treatment still lacks in vivo evidence. This study assessed the effect of FIR therapy on SCA3 in vivo by using a mouse model over 28 weeks. Control mice carried a healthy wild-type ATXN3 allele that had a polyglutamine tract with 15 CAG repeats (15Q), whereas SCA3 transgenic mice possessed an allele with a pathological polyglutamine tract with expanded 84 CAG (84Q) repeats. The results showed that the 84Q SCA3 mice displayed impaired motor coordination, balance abilities, and gait performance, along with the associated loss of Purkinje cells in the cerebellum, compared with the normal 15Q controls; nevertheless, FIR treatment was sufficient to prevent those defects. FIR significantly improved performance in terms of maximal contact area, stride length, and base support in the forepaws, hindpaws, or both. Moreover, FIR treatment supported the survival of Purkinje cells in the cerebellum and promoted the autophagy, as reflected by the induction of autophagic markers, LC3II and Beclin-1, concomitant with the reduction of p62 and ataxin-3 accumulation in cerebellar Purkinje cells, which might partially contribute to the rescue mechanism. In summary, our results reveal that FIR confers therapeutic effects in an SCA3 transgenic animal model and therefore has considerable potential for future clinical use.

Aminoglycoside-associated nonsyndromic deafness and speech disorder in mitochondrial A1555G mutation in a family: A case report.

RATIONALE: Mitochondrial DNA mutations have been associated with many maternal inherited diseases. A1555G mutation in mtDNA effects the gene code for rRNA, resulting in the structural change of human ribosome rending it susceptible to binding of the common antibiotic, aminoglycosides. Such mutation has linked with non-syndromic hearing loss and is one of the most common mtDNA mutations in Asian populations. PATIENT CONCERNS: A 50-year-old Taiwanese female visited our neurology department with concern for multiple members with hearing loss in her family, including herself. DIAGNOSES: Physical examination findings were not significant besides hearing loss and brain MRI did not reveal any lesions. BAEP confirmed bilateral peripheral sensory deficit. Given the multiple cases of hearing loss in the family, a genetic cause was suspected. Using PCR and sequences chromatogram technique we have identified A1555G mutation on her mtDNA affecting region codes for 12S rRNA. Additionally, we observed severe speech disorder in two young family members with the onset of hearing loss began in their early childhood. INTERVENTIONS: The patient declined any form of intervention at the time for personal reasons. OUTCOMES: The patient was satisfied with the diagnosis, her and her families are continuously followed by our neurology department. LESSONS: We report on a family with mtDNA mutation hearing loss that is related to exposure to aminoglycosides. Children with such mutation are at high risk for impaired linguistic function. Early identification and intervention with cochlear implant should be considered.

A prospective study of mitochondrial DNA copy number and the risk of prostate cancer.

PURPOSE: Evidence suggests that mitochondrial DNA (mtDNA) copy number increases in response to DNA damage. Increased mtDNA copy number has been observed in prostate cancer (PCa) cells, suggesting a role in PCa development, but this association has not yet been investigated prospectively. METHODS: We conducted a nested case-control study (793 cases and 790 controls) of men randomized to the screening arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) to evaluate the association between pre-diagnosis mtDNA copy number, measured in peripheral blood leukocytes, and the risk of PCa. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) and polytomous logistic regression to analyze differences in associations by non-aggressive (Stage I/II AND Gleason grade < 8) or aggressive (Stage III/IV OR Gleason grade ≥ 8) PCa. RESULTS: Although mtDNA copy number was not significantly associated with PCa risk overall (OR 1.23, 95% CI 0.97-1.55, p = 0.089), increasing mtDNA copy number was associated with an increased risk of non-aggressive PCa (OR 1.29, 95% CI 1.01-1.65, p = 0.044) compared to controls. No association was observed with aggressive PCa (OR 1.02, 95% CI 0.64-1.63, p = 0.933). Higher mtDNA copy number was also associated with increased PSA levels among controls (p = 0.014). CONCLUSIONS: These results suggest that alterations in mtDNA copy number may reflect disruption of the normal prostate glandular architecture seen in early-stage disease, as opposed to reflecting the large number of tumor cells seen with advanced PCa.

Mitochondria DNA change and oxidative damage in clinically stable patients with major depressive disorder.

BACKGROUND: To compare alterations of mitochondria DNA (mtDNA) copy number, single nucleotide polymorphisms (SNPs), and oxidative damage of mtDNA in clinically stable patients with major depressive disorder (MDD). METHODS: Patients met DSM-IV diagnostic criteria for MDD were recruited from the psychiatric outpatient clinic at Changhua Christian Hospital, Taiwan. They were clinically stable and their medications had not changed for at least the preceding two months. Exclusion criteria were substance-induced psychotic disorder, eating disorder, anxiety disorder or illicit substance abuse. Comparison subjects did not have any major psychiatric disorder and they were medically healthy. Peripheral blood leukocytes were analyzed to compare copy number, SNPs and oxidative damage of mtDNA between the two groups. RESULTS: 40 MDD patients and 70 comparison subjects were collected. The median age of the subjects was 42 years and 38 years in MDD and comparison groups, respectively. Leukocyte mtDNA copy number of MDD patients was significantly lower than that of the comparison group (p = 0.037). MDD patients had significantly higher mitochondrial oxidative damage than the comparison group (6.44 vs. 3.90, p<0.001). After generalized linear model adjusted for age, sex, smoking, family history, and psychotropic use, mtDNA copy number was still significantly lower in the MDD group (p<0.001). MtDNA oxidative damage was positively correlated with age (p<0.001) and MDD (p<0.001). Antipsychotic use was negatively associated with mtDNA copy number (p = 0.036). LIMITATIONS: The study is cross-sectional with no longitudinal follow up. The cohort is clinically stable and generalizability of our result to other cohort should be considered. CONCLUSIONS: Our study suggests that oxidative stress and mitochondria may play a role in the pathophysiology of MDD. More large-scale studies are warranted to assess the interplay between oxidative stress, mitochondria dysfunction and MDD.

Pooled analysis of mitochondrial DNA copy number and lung cancer risk in three prospective studies.

BACKGROUND: We previously reported that higher levels of mitochondrial DNA copy number (mtDNA CN) were associated with lung cancer risk among male heavy smokers (i.e., ≥20 cigarettes per day) in the Alpha-Tocopherol Beta-Carotene (ATBC) study. Here, we present two additional prospective investigations nested in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial and the Shanghai Women's Health Study (SWHS), and pooled with previously published data from ATBC. MATERIALS: All DNA were extracted from peripheral whole blood samples using the phenol-chloroform method, and mtDNA CN was assayed by fluorescence-based qPCR. Multivariate unconditional logistic regression models were used to estimate ORs and 95% confidence intervals for the association of mtDNA CN and lung cancer risk. RESULTS: Overall, mtDNA CN was not associated with lung cancer risk in the PLCO, SWHS, or pooled populations (all P trends > 0.42, P heterogeneity = 0.0001), and mtDNA CN was inversely associated with lung cancer risk among male smokers in PLCO, the opposite direction observed in ATBC. In addition, the mtDNA CN association observed among male heavy smokers in ATBC was the opposite direction in PLCO. CONCLUSIONS: mtDNA CN was not consistently associated with lung cancer risk across three prospective study populations from Europe, Asia, and the United States. IMPACT: This pooled study suggests no consistent association between prediagnostic mtDNA CN levels and lung cancer risk across several populations. Cancer Epidemiol Biomarkers Prev; 23(12); 2977-80. ©2014 AACR.

Delivering healthy mitochondria for the therapy of mitochondrial diseases and beyond.

Mitochondrial transfer has been demonstrated to a play a physiological role in the rescuing of mitochondrial DNA deficient cells by co-culture with human mesenchymal stem cells. The successful replacement of mitochondria using microinjection into the embryo has been revealed to improve embryo maturation. Evidence of mitochondrial transfer has been shown to minimize injury of the ischemic-reperfusion rabbit heart model. In this mini review, the therapeutic strategies of mitochondrial diseases based on the concept of mitochondrial transfer are illustrated, as well as a novel approach to peptide-mediated mitochondrial delivery. The possible mechanism of peptide-mediated mitochondrial delivery in the treatment of the myoclonic epilepsy and ragged-red fiber disease is summarized. Understanding the feasibility of mitochondrial manipulation in cells facilitates novel therapeutic skills in the future clinical practice of mitochondrial disorder.

Mitochondrial DNA variation and increased oxidative damage in euthymic patients with bipolar disorder.

AIM: The aim of this study was to compare alterations of mitochondrial DNA (mtDNA) copy number, single nucleotide polymorphisms, and oxidative damage of mtDNA in clinically stable patients with bipolar I disorder (BD). METHODS: Patients meeting DSM-IV diagnostic criteria for BD were recruited from the psychiatric outpatient clinic at Changhua Christian Hospital, Taiwan. They were clinically stable and their medications had not changed for at least the preceding 2 months. Exclusion criteria were substance-induced psychotic disorder, eating disorder, anxiety disorder or illicit substance abuse. Comparison subjects did not have any history of major psychiatric disorders and they were non-smokers. By analyzing peripheral blood leukocytes, copy number, single nucleotide polymorphisms and oxidative damage of mtDNA were compared between the two groups. RESULTS: The median age of the subjects was 38 years and 41.5 years in the comparison and BD groups, respectively. The leukocyte mtDNA copy number of the BD group was significantly lower than that of the comparison group (P < 0.001). BD patients had significantly higher mitochondrial oxidative damage than the comparison group (6.1 vs 3.9, P < 0.001). After generalized linear model adjusting with age, sex, smoking, family history, and psychotropic use, mtDNA copy number was still significantly lower in the BD group (P < 0.001). MtDNA oxidative damage was positively correlated with age (P = 0.034), although mtDNA oxidative damage was similar between these two groups. CONCLUSION: Possible involvement of oxidative stress and mitochondria in the pathophysiology of BD needs more large-scale studies. It is important that psychiatrists retain a high level of suspicion for mitochondrial dysfunction in patients with bipolar disorder.

A nested case-control study of leukocyte mitochondrial DNA copy number and renal cell carcinoma in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

Mitochondrial DNA (mtDNA) is vulnerable to mutations, and the number of copies of mtDNA per cell may increase to compensate for DNA damage. Case-control studies have reported associations between altered mtDNA copy number and risk of renal cell carcinoma (RCC); however, this association has not been investigated prospectively. We conducted a nested case-control study (252 cases and 504 controls) of RCC risk in relation to pre-diagnostic leukocyte mtDNA copy number in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. mtDNA copy number was measured in triplicate using a fluorescence-based quantitative PCR assay; samples from 22 cases and 36 controls could not be assayed, leaving 230 cases and 468 controls for analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. High mtDNA copy number was associated with an increased risk of RCC, both overall (highest quartile versus lowest: OR = 2.0, 95% CI = 1.2-3.2; P trend = 0.002) and among cases diagnosed ≥6 years after blood collection (OR = 2.6, 95% CI = 1.4-5.0; P trend = 0.003). These findings did not differ significantly by sex, body mass index, history of hypertension or smoking status (P interaction ≥ 0.3). Results of this study suggest that high pre-diagnostic leukocyte mtDNA copy number, a suspected marker of oxidative DNA damage and mitochondrial dysfunction, is associated with increased future RCC risk.

Decreased mitochondrial deoxyribonucleic acid and increased oxidative damage in chronic hepatitis C.

AIM: To determine whether alteration of the mitochondria DNA (mtDNA) copy number and its oxidative damage index (mtDNA(∆CT)) can be detected by analysis of peripheral blood cells in hepatitis C virus (HCV)-infected patients. METHODS: This study enrolled two groups of patients aged 40-60 years: a control group and an HCV-infected group in Department of Gastroenterology and Hepatology in Changhua Christian Hospital. Patients with co-infection with hepatitis B virus or human immunodeficiency virus, autoimmune disease, malignant neoplasia, pregnancy, thyroid disease, or alcohol consumption > 40 g/d were excluded. HCV-infected patients who met the following criteria were included: (1) positive HCV antibodies for > 6 mo; (2) alanine aminotransferase (ALT) levels more than twice the upper limit of normal on at least two occasions during the past 6 mo; and (3) histological fibrosis stage higher than F1. The mtDNA copy number and oxidative damage index of HCV mtDNA (mtDNA(∆CT)) were measured in peripheral blood leukocytes. The association between mtDNA copy number and mtDNA(∆CT) was further analyzed using clinical data. RESULTS: Forty-seven normal controls (male/female: 26/21, mean age 50.51 ± 6.15 years) and 132 HCV-infected patients (male/female: 76/61, mean age 51.65 ± 5.50 years) were included in the study. The genotypes of HCV-infected patients include type 1a (n = 3), type 1b (n = 83), type 2a (n = 32), and type 2b (n = 14). Liver fibrosis stages were distributed as follows: F1/F2/F3/F4 = 1/61/45/25 and activity scores were A0/A1/A2/A3 = 7/45/55/25. There were no age or gender differences between the two groups. HCV-infected patients had higher hepatitis activity (aspartate transaminase levels 108.77 ± 60.73 vs 23.19 ± 5.47, P < 0.01; ALT levels 168.69 ± 93.12 vs 23.15 ± 9.45, P < 0.01) and lower platelet count (170.40 ± 58.00 vs 251.24 ± 63.42, P < 0.01) than controls. The mtDNA copy number was lower in HCV-infected patients than in controls (173.49 vs 247.93, P < 0.05). The mtDNA(∆CT) was higher in HCV-infected patients than in controls (2.92 vs 0.64, P < 0.05). To clarify the clinical significance of these results in HCV-infected patients, their association with different clinical parameters among HCV-infected patients was analyzed. A negative association was found between mtDNA copy number and elevated aspartate transaminase levels (r = -0.17, P < 0.05). Changes in mtDNA copy number were not associated with HCV RNA levels, HCV genotypes, liver fibrosis severity, or inflammatory activity in the liver biopsy specimen. However, a correlation was observed between mtDNA(∆CT) and platelet count (r = -0.22, P < 0.01), HCV RNA level (r = 0.36, P < 0.01), and hepatitis activity (r = 0.20, P = 0.02). However, no difference in the change in mtDNA(∆CT) was observed between different fibrosis stages or HCV genotypes. CONCLUSION: Oxidative stress and mtDNA damage are detectable in patient's peripheral leukocytes. Increased leukocyte mtDNA(∆CT) correlates with higher HCV viremia, increased hepatitis activity, and lower platelet count.

Depleted leukocyte mitochondrial DNA copy number in metabolic syndrome.

AIMS: Metabolic syndrome (MetS) is characterized by a group of defects of metabolic origin which are possibly involved in mitochondrial DNA (mtDNA) alteration of mtDNA content [Lee et al. Exp Biol Med, 2007; 232(5):592-606]. The present study was undertaken to ascertain whether alteration of leukocyte mtDNA copy number is related to MetS. METHODS: Eighty non-MetS subjects and 50 subjects with MetS were recruited. The mtDNA copy number of leukocytes from each group of subjects was measured using quantitative polymerase chain reaction. RESULTS: The mtDNA copy number of leukocytes in subjects with MetS was significantly lower than that of non-MetS subjects. Depleted mtDNA copy number is correlated with lower plasma HDL, higher triglyceride, higher HOMA-IR and hypertension, and is even more sensitive to MetS criteria. CONCLUSIONS: Depleted leukocyte mtDNA copy number is related to the severity of MetS. Alteration of mtDNA copy number in leukocytes is proposed as a MetS biomarker involved in the bioenergetic change of mitochondria.