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Atici AE, Crother TR, Noval Rivas M. Mitochondrial quality control in health and cardiovascular diseases. Front Cell Dev Biol 2023; 11:1290046. [PMID: 38020895 PMCID: PMC10657886 DOI: 10.3389/fcell.2023.1290046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Cardiovascular diseases (CVDs) are one of the primary causes of mortality worldwide. An optimal mitochondrial function is central to supplying tissues with high energy demand, such as the cardiovascular system. In addition to producing ATP as a power source, mitochondria are also heavily involved in adaptation to environmental stress and fine-tuning tissue functions. Mitochondrial quality control (MQC) through fission, fusion, mitophagy, and biogenesis ensures the clearance of dysfunctional mitochondria and preserves mitochondrial homeostasis in cardiovascular tissues. Furthermore, mitochondria generate reactive oxygen species (ROS), which trigger the production of pro-inflammatory cytokines and regulate cell survival. Mitochondrial dysfunction has been implicated in multiple CVDs, including ischemia-reperfusion (I/R), atherosclerosis, heart failure, cardiac hypertrophy, hypertension, diabetic and genetic cardiomyopathies, and Kawasaki Disease (KD). Thus, MQC is pivotal in promoting cardiovascular health. Here, we outline the mechanisms of MQC and discuss the current literature on mitochondrial adaptation in CVDs.
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Affiliation(s)
- Asli E. Atici
- Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children’s at Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Infectious and Immunologic Diseases Research Center (IIDRC), Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Timothy R. Crother
- Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children’s at Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Infectious and Immunologic Diseases Research Center (IIDRC), Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Magali Noval Rivas
- Department of Pediatrics, Division of Infectious Diseases and Immunology, Guerin Children’s at Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Infectious and Immunologic Diseases Research Center (IIDRC), Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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Vallbona-Garcia A, Hamers IHJ, van Tienen FHJ, Ochoteco-Asensio J, Berendschot TTJM, de Coo IFM, Benedikter BJ, Webers CAB, Smeets HJM, Gorgels TGMF. Low mitochondrial DNA copy number in buffy coat DNA of primary open-angle glaucoma patients. Exp Eye Res 2023; 232:109500. [PMID: 37178956 DOI: 10.1016/j.exer.2023.109500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/22/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023]
Abstract
Primary open-angle glaucoma (POAG) is characterized by optic nerve degeneration and irreversible loss of retinal ganglion cells (RGCs). The pathophysiology is not fully understood. Since RGCs have a high energy demand, suboptimal mitochondrial function may put the survival of these neurons at risk. In the present study, we explored whether mtDNA copy number or mtDNA deletions could reveal a mitochondrial component in POAG pathophysiology. Buffy coat DNA was isolated from EDTA blood of age- and sex-matched study groups, namely POAG patients with high intraocular pressure (IOP) at diagnosis (high tension glaucoma: HTG; n = 97), normal tension glaucoma patients (NTG, n = 37), ocular hypertensive controls (n = 9), and cataract controls (without glaucoma; n = 32), all without remarkable comorbidities. The number of mtDNA copies was assessed through qPCR quantification of the mitochondrial D-loop and nuclear B2M gene. Presence of the common 4977 base pair mtDNA deletion was assessed by a highly sensitive breakpoint PCR. Analysis showed that HTG patients had a lower number of mtDNA copies per nuclear DNA than NTG patients (p-value <0.01, Dunn test) and controls (p-value <0.001, Dunn test). The common 4977 base pair mtDNA deletion was not detected in any of the participants. A lower mtDNA copy number in blood of HTG patients suggests a role for a genetically defined, deficient mtDNA replication in the pathology of HTG. This may cause a low number of mtDNA copies in RGCs, which together with aging and high IOP, may lead to mitochondrial dysfunction, and contribute to glaucoma pathology.
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Affiliation(s)
- Antoni Vallbona-Garcia
- University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands; Department of Toxicogenomics, Maastricht University, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Ilse H J Hamers
- Department of Toxicogenomics, Maastricht University, Maastricht, the Netherlands
| | - Florence H J van Tienen
- Department of Toxicogenomics, Maastricht University, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | | | - Tos T J M Berendschot
- University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Irenaeus F M de Coo
- Department of Toxicogenomics, Maastricht University, Maastricht, the Netherlands
| | - Birke J Benedikter
- University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Carroll A B Webers
- University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Hubert J M Smeets
- Department of Toxicogenomics, Maastricht University, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Theo G M F Gorgels
- University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
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Wu TH, Peng J, Yang L, Chen YH, Lu XL, Huang JT, You JY, Ou-Yang WX, Sun YY, Xue YN, Mao X, Yan HM, Ren RN, Xie J, Chen ZH, Zhang VW, Lyu GZ, He F. Use of dual genomic sequencing to screen mitochondrial diseases in pediatrics: a retrospective analysis. Sci Rep 2023; 13:4193. [PMID: 36918699 PMCID: PMC10015028 DOI: 10.1038/s41598-023-31134-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/07/2023] [Indexed: 03/16/2023] Open
Abstract
Mitochondrial diseases (MDs) were a large group multisystem disorders, attributable in part to the dual genomic control. The advent of massively sequencing has improved diagnostic rates and speed, and was increasingly being used as a first-line diagnostic test. Paediatric patients (aged < 18 years) who underwent dual genomic sequencing were enrolled in this retrospective multicentre study. We evaluated the mitochondrial disease criteria (MDC) and molecular diagnostic yield of dual genomic sequencing. Causative variants were identified in 177 out of 503 (35.2%) patients using dual genomic sequencing. Forty-six patients (9.1%) had mitochondria-related variants, including 25 patients with nuclear DNA (nDNA) variants, 15 with mitochondrial DNA (mtDNA) variants, and six with dual genomic variants (MT-ND6 and POLG; MT-ND5 and RARS2; MT-TL1 and NARS2; MT-CO2 and NDUFS1; MT-CYB and SMARCA2; and CHRNA4 and MT-CO3). Based on the MDC, 15.2% of the patients with mitochondria-related variants were classified as "unlikely to have mitochondrial disorder". Moreover, 4.5% of the patients with non-mitochondria-related variants and 1.43% with negative genetic tests, were classified as "probably having mitochondrial disorder". Dual genomic sequencing in suspected MDs provided a more comprehensive and accurate diagnosis for pediatric patients, especially for patients with dual genomic variants.
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Affiliation(s)
- Teng-Hui Wu
- Department of Pediatrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Li Yang
- Department of Pediatrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Yan-Hui Chen
- Department of Pediatrics, Fujian Medical University Union Hospital, 29 Xinquan Road, Fuzhou, Fujian, China
| | - Xiu-Lan Lu
- Department of Pediatric Intensive Care Unit, Hunan Children's Hospital, 86 Ziyuan Road, Changsha, Hunan, China
| | - Jiao-Tian Huang
- Department of Pediatric Intensive Care Unit, Hunan Children's Hospital, 86 Ziyuan Road, Changsha, Hunan, China
| | - Jie-Yu You
- Department of Gastroenterology and Nutrition, Hunan Children's Hospital, 86 Ziyuan Road, Changsha, Hunan, China
| | - Wen-Xian Ou-Yang
- Department of Hepatopathy, Hunan Children's Hospital, 86 Ziyuan Road, Changsha, Hunan, China
| | - Yue-Yu Sun
- Department of Pediatric Intensive Care Unit, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences (GAMS), 106 Zhongshan 2nd Road, Guangzhou, Guangdong, China
| | - Yi-Nan Xue
- Department of Pediatrics, Brain Hospital of Hunan Province, 427 Furong Road, Changsha, Hunan, China
| | - Xiao Mao
- Department of Medical Genetics, Maternal,, Child Health Hospital of Hunan Province, 53 Xiangchun Road, Changsha, Hunan, China
| | - Hui-Ming Yan
- Department of Medical Genetics, Maternal,, Child Health Hospital of Hunan Province, 53 Xiangchun Road, Changsha, Hunan, China
| | - Rong-Na Ren
- Department of Pediatrics, The 900Th Hospital of Joint Logistic Support Force, PLA, Fuzhou, Fujian, China
| | - Jing Xie
- Department of Pediatrics, The First Hospital of Hunan University of Chinese Medicine, 95 Shaoshan Road, Changsha, Hunan, China
| | - Zhi-Heng Chen
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, Hunan, China
| | - Victor-Wei Zhang
- Amcare Genomics Laboratory, Guangzhou, Guangdong, China.,Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Gui-Zhen Lyu
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Fang He
- Department of Pediatrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China.
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Primary and Secondary Mitochondrial Diseases: Etiologies and Therapeutic Strategies. J Clin Med 2022; 11:jcm11144209. [PMID: 35887983 PMCID: PMC9323767 DOI: 10.3390/jcm11144209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 02/04/2023] Open
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Quebedeaux TM, Song H, Giwa-Otusajo J, Thompson LP. Chronic Hypoxia Inhibits Respiratory Complex IV Activity and Disrupts Mitochondrial Dynamics in the Fetal Guinea Pig Forebrain. Reprod Sci 2022; 29:184-192. [PMID: 34750769 DOI: 10.1007/s43032-021-00779-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 10/19/2021] [Indexed: 11/25/2022]
Abstract
Mitochondrial dysfunction is an underlying cause of childhood neurological disease secondary to the crucial role of mitochondria in proper neurodevelopment. We hypothesized that chronic intrauterine hypoxia (HPX) induces mitochondrial deficits by altering mitochondrial biogenesis and dynamics in the fetal brain. Pregnant guinea pigs were exposed to either normoxia (NMX, 21%O2) or HPX (10.5%O2) starting at 28-day (early onset, EO-HPX) or 50-day (late onset, LO-HPX) gestation until term (65 days). Near-term male and female fetuses were extracted from anesthetized sows, and mitochondria were isolated from excised fetal forebrains (n = 6/group). Expression of mitochondrial complex subunits I-V (CI-CV), fission (Drp-1), and fusion (Mfn-2) proteins was measured by Western blot. CI and CIV enzyme activities were measured by colorimetric assays. Chronic HPX reduced fetal body wts and increased (P < 0.05) brain/body wt ratios of both sexes. CV subunit levels were increased in EO-HPX males only and CII levels increased in LO-HPX females only compared to NMX. Both EO- and LO-HPX decreased CIV activity in both sexes but had no effect on CI activity. EO-HPX increased Drp1 and decreased Mfn2 levels in males, while LO-HPX had no effect on either protein levels. In females, both EO-HPX and LO-HPX increased Drp1 but had no effect on Mfn2 levels. Chronic HPX alters abundance and activity of select complex subunits and shifts mitochondrial dynamics toward fission in a sex-dependent manner in the fetal guinea pig brain. This may be an underlying mechanism of reduced respiratory efficiency leading to disrupted metabolism and increased vulnerability to a second neurological injury at the time of birth in HPX fetal brains.
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Affiliation(s)
- Tabitha M Quebedeaux
- Department of Obstetrics, Gynecology, & Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD, 21201, USA
| | - Hong Song
- Department of Obstetrics, Gynecology, & Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD, 21201, USA
| | - Jamiu Giwa-Otusajo
- Department of Obstetrics, Gynecology, & Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD, 21201, USA
| | - Loren P Thompson
- Department of Obstetrics, Gynecology, & Reproductive Sciences, University of Maryland, Baltimore, School of Medicine, 655 W. Baltimore St., Baltimore, MD, 21201, USA.
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Gucek M, Sack MN. Proteomic and metabolomic advances uncover biomarkers of mitochondrial disease pathophysiology and severity. J Clin Invest 2021; 131:145158. [PMID: 33463543 PMCID: PMC7810475 DOI: 10.1172/jci145158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Advancing proteomic and metabolomic technologies that integrate curated omic databases have crossed a threshold to enable their clinical utility. In this issue of the JCI, Sharma et al. exploit emerging technologies to evaluate whether biomarkers identified in the mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) syndrome could refine disease characterization, uncover pathways to monitor therapeutic efficacy, and/or delineate disease-modifying targets. The authors analyzed blood and urine samples from patients with this genetic mitochondrial disease and elucidated proteins and metabolites related to NADH-reductive stress. These circulating biomarkers have intriguing clinical potential that implicate disease pathophysiology and may prove important biomarkers for the future management of MELAS.
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Affiliation(s)
| | - Michael N. Sack
- Laboratory of Mitochondrial Biology and Metabolism National Heart, Lung and Blood Institute, NIH, Bethesda, Maryland, USA
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Naess K, Bruhn H, Stranneheim H, Freyer C, Wibom R, Mourier A, Engvall M, Nennesmo I, Lesko N, Wredenberg A, Wedell A, von Döbeln U. Clinical Presentation, Genetic Etiology, and Coenzyme Q10 Levels in 55 Children with Combined Enzyme Deficiencies of the Mitochondrial Respiratory Chain. J Pediatr 2021; 228:240-251.e2. [PMID: 32827528 DOI: 10.1016/j.jpeds.2020.08.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/10/2020] [Accepted: 08/10/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To evaluate the clinical symptoms and biochemical findings and establish the genetic etiology in a cohort of pediatric patients with combined deficiencies of the mitochondrial respiratory chain complexes. STUDY DESIGN Clinical and biochemical data were collected from 55 children. All patients were subjected to sequence analysis of the entire mitochondrial genome, except when the causative mutations had been identified based on the clinical picture. Whole exome sequencing/whole genome sequencing (WES/WGS) was performed in 32 patients. RESULTS Onset of disease was generally early in life (median age, 6 weeks). The most common symptoms were muscle weakness, hypotonia, and developmental delay/intellectual disability. Nonneurologic symptoms were frequent. Disease causing mutations were found in 20 different nuclear genes, and 7 patients had mutations in mitochondrial DNA. Causative variants were found in 18 of the 32 patients subjected to WES/WGS. Interestingly, many patients had low levels of coenzyme Q10 in muscle, irrespective of genetic cause. CONCLUSIONS Children with combined enzyme defects display a diversity of clinical symptoms with varying age of presentation. We established the genetic diagnosis in 35 of the 55 patients (64%). The high diagnostic yield was achieved by the introduction of massive parallel sequencing, which also revealed novel genes and enabled elucidation of new disease mechanisms.
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Affiliation(s)
- Karin Naess
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
| | - Helene Bruhn
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Stranneheim
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Christoph Freyer
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Arnaud Mourier
- CNRS UMR 5095, Bordeaux Cedex, France; University of Bordeaux, EPST, IBGC UMR 5095, Bordeaux Cedex, France
| | - Martin Engvall
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Inger Nennesmo
- Clinical Pathology, Karolinska University Hospital, Department of Laboratory Medicine, Stockholm, Sweden
| | - Nicole Lesko
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika von Döbeln
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Ji L, Liao T, Yang J, Su H, Song J, Qian K. Deep sequencing shows that accumulation of potentially pathogenic mtDNA mutations rather than mtDNA copy numbers may be associated with early embryonic loss. J Assist Reprod Genet 2020; 37:2181-2188. [PMID: 32700162 PMCID: PMC7492355 DOI: 10.1007/s10815-020-01893-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/02/2020] [Indexed: 10/28/2022] Open
Abstract
PURPOSE To explore the relationship between mitochondrial DNA quantity and heteroplasmy and early embryonic loss. METHODS A total of 150 villous samples from patients with spontaneous abortion (SA, n = 75) or induced abortion (IA, n = 75) were collected. qPCR and next-generation sequencing (NGS) were used to test mitochondrial DNA quantity and heteroplasmy. Missense mutations with a CADD score > 15 and heteroplasmy ≥ 70% were defined as potentially pathogenic mutations. RESULTS With respect to mitochondrial DNA copy numbers, there was no significant difference between the SA and IA groups (median (IQR), 566 (397-791) vs. 614 (457-739); P = 0.768) or between the euploid and aneuploid groups (median (IQR), 516 (345-730) vs. 599 (423-839); P = 0.107). mtDNA copy numbers were not associated with spontaneous abortion using logistic regression analysis (P = 0.196, 95% CI 1.000-1.001). In addition, more patients harbored possibly pathogenic mtDNA mutations in their chorionic villi in the SA group (70.7%, 53/75) compared with the IA group (54.7%, 41/75; P < 0.05). However, there was no statistical difference between the euploid (80%, 24/30) and aneuploid groups (64.4%, 29/45; p = 0.147). CONCLUSION Early embryonic loss and the formation of aneuploidy were not related to mtDNA copy number. Patients with spontaneous abortion were more likely to have possibly pathogenic mutations in their mtDNA, and this may assist in purifying pathogenic mtDNA. However, whether the accumulation of these potentially morbific mtDNA mutations caused early embryonic loss requires further investigation.
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Affiliation(s)
- Licheng Ji
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, 430030, Hubei, China
| | - Tingting Liao
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, 430030, Hubei, China.
| | - Juan Yang
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, 430030, Hubei, China
| | - Houming Su
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, 430030, Hubei, China
| | - Jianyuan Song
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, No.1 Shang Cheng Avenue, Yiwu, Zhejiang, 322000, China
| | - Kun Qian
- Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 JieFang Avenue, Wuhan, 430030, Hubei, China.
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Haroon S, Li A, Weinert JL, Fritsch C, Ericson NG, Alexander-Floyd J, Braeckman BP, Haynes CM, Bielas JH, Gidalevitz T, Vermulst M. Multiple Molecular Mechanisms Rescue mtDNA Disease in C. elegans. Cell Rep 2019; 22:3115-3125. [PMID: 29562168 PMCID: PMC6106782 DOI: 10.1016/j.celrep.2018.02.099] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 12/07/2017] [Accepted: 02/25/2018] [Indexed: 01/03/2023] Open
Abstract
Genetic instability of the mitochondrial genome (mtDNA) plays an important role in human aging and disease. Thus far, it has proven difficult to develop successful treatment strategies for diseases that are caused by mtDNA instability. To address this issue, we developed a model of mtDNA disease in the nematode C. elegans, an animal model that can rapidly be screened for genes and biological pathways that reduce mitochondrial pathology. These worms recapitulate all the major hallmarks of mtDNA disease in humans, including increased mtDNA instability, loss of respiration, reduced neuromuscular function, and a shortened lifespan. We found that these phenotypes could be rescued by intervening in numerous biological pathways, including IGF-1/insulin signaling, mitophagy, and the mitochondrial unfolded protein response, suggesting that it may be possible to ameliorate mtDNA disease through multiple molecular mechanisms.
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Affiliation(s)
- Suraiya Haroon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, PA 19104, USA
| | - Annie Li
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, PA 19104, USA
| | - Jaye L Weinert
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, PA 19104, USA
| | - Clark Fritsch
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, PA 19104, USA
| | - Nolan G Ericson
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Bart P Braeckman
- Laboratory of Aging Physiology and Molecular Evolution, Biology Department, Ghent University, 9000 Ghent, Belgium
| | - Cole M Haynes
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jason H Bielas
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Tali Gidalevitz
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Marc Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, PA 19104, USA.
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Haroon S, Vermulst M. Oxygen Consumption Measurements in Caenorhabditis elegans Using the Seahorse XF24. Bio Protoc 2019; 9:e3288. [PMID: 33654802 DOI: 10.21769/bioprotoc.3288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 05/26/2019] [Accepted: 06/11/2019] [Indexed: 11/02/2022] Open
Abstract
Mitochondria generate 90% of the energy required to sustain life. As a result, loss of mitochondrial function compromises almost every facet of human physiology. Accordingly, most mitochondrial diseases tend to present themselves as complex, multi-systemic disorders that can be difficult to diagnose. Depending on the severity of the mitochondrial dysfunction, the pathology can range from mild discomfort to severe epilepsy, blindness and paralysis. To develop therapies to these diseases, it will be important to optimize experimental techniques that can reliably quantify mitochondrial function, particularly in live cells or intact organisms. Here, we describe how a Seahorse XF24 Analyzer can be used to measure both basal and maximal respiration in the nematode Caenorhabditis elegans, and how this data can be interpreted to evaluate mitochondrial function.
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Affiliation(s)
- Suraiya Haroon
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Marc Vermulst
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
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Naeem MM, Sondheimer N. Heteroplasmy Shifting as Therapy for Mitochondrial Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1158:257-267. [PMID: 31452145 DOI: 10.1007/978-981-13-8367-0_14] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mitochondrial disease can arise due to pathogenic sequence variants in the mitochondrial DNA (mtDNA) that prevent cells from meeting their energy demands. Mitochondrial diseases are often fatal and currently there are no treatments directed towards the underlying cause of disease. Pathogenic variants in mtDNA often exist in a state of heteroplasmy, with coexistence of pathogenic and wild type mtDNA. The load of heteroplasmy, defined as the relative amount of pathogenic mtDNA to wild type mtDNA, corresponds to timing and symptom severity. Thus, changing the heteroplasmy load may lead to a shift in disease onset and symptom severity. Here we review techniques aimed at preventing inheritance of pathogenic mtDNA via mitochondrial replacement therapy (MRT) and strategies geared toward shifting of heteroplasmy in individuals with active mitochondrial disease. MRT strategies seek to create embryos with the nuclear genetic makeup of the intended parents and wild type mtDNA from a donor in order to avoid known maternal pathogenic variants. Heteroplasmy shift approaches in patients are of two categories: nuclease dependent and nuclease independent strategies. Despite initial success in mouse models and patient cells, these techniques have not reached clinical use. Translational attempts in this area are urgently needed to improve therapies for a currently untreatable set of disorders.
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Affiliation(s)
- Mansur M Naeem
- Institute of Medical Science, The University of Toronto, Toronto, ON, Canada
| | - Neal Sondheimer
- Institute of Medical Science, The University of Toronto, Toronto, ON, Canada.
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12
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Simard ML, Mourier A, Greaves LC, Taylor RW, Stewart JB. A novel histochemistry assay to assess and quantify focal cytochrome c oxidase deficiency. J Pathol 2018; 245:311-323. [PMID: 29660116 PMCID: PMC6032845 DOI: 10.1002/path.5084] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 03/12/2018] [Accepted: 04/05/2018] [Indexed: 01/25/2023]
Abstract
Defects in the respiratory chain, interfering with energy production in the cell, are major underlying causes of mitochondrial diseases. In spite of this, the surprising variety of clinical symptoms, disparity between ages of onset, as well as the involvement of mitochondrial impairment in ageing and age‐related diseases continue to challenge our understanding of the pathogenic processes. This complexity can be in part attributed to the unique metabolic needs of organs or of various cell types. In this view, it remains essential to investigate mitochondrial dysfunction at the cellular level. For this purpose, we developed a novel enzyme histochemical method that enables precise quantification in fresh‐frozen tissues using competing redox reactions which ultimately lead to the reduction of tetrazolium salts and formazan deposition in cytochrome c oxidase‐deficient mitochondria. We demonstrate that the loss of oxidative activity is detected at very low levels – this achievement is unequalled by previous techniques and opens up new opportunities for the study of early disease processes or comparative investigations. Moreover, human biopsy samples of mitochondrial disease patients of diverse genotypic origins were used and the successful detection of COX‐deficient cells suggests a broad application for this new method. Lastly, the assay can be adapted to a wide range of tissues in the mouse and extends to other animal models, which we show here with the fruit fly, Drosophila melanogaster. Overall, the new assay provides the means to quantify and map, on a cell‐by‐cell basis, the full extent of COX deficiency in tissues, thereby expending new possibilities for future investigation. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
| | - Arnaud Mourier
- Max Planck Institute for Biology of Ageing, Cologne, Germany.,CNRS, Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, UMR5095, Bordeaux, France
| | - Laura C Greaves
- Newcastle University LLHW Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK.,Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Mitochondrial Diagnostic Laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - James B Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
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13
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Wang A, Mouser J, Pitt J, Promislow D, Kaeberlein M. Rapamycin enhances survival in a Drosophila model of mitochondrial disease. Oncotarget 2018; 7:80131-80139. [PMID: 27741510 PMCID: PMC5348310 DOI: 10.18632/oncotarget.12560] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/27/2016] [Indexed: 11/25/2022] Open
Abstract
Pediatric mitochondrial disorders are a devastating category of diseases caused by deficiencies in mitochondrial function. Leigh Syndrome (LS) is the most common of these diseases with symptoms typically appearing within the first year of birth and progressing rapidly until death, usually by 6-7 years of age. Our lab has recently shown that genetic inhibition of the mechanistic target of rapamycin (TOR) rescues the short lifespan of yeast mutants with defective mitochondrial function, and that pharmacological inhibition of TOR by administration of rapamycin significantly rescues the shortened lifespan, neurological symptoms, and neurodegeneration in a mouse model of LS. However, the mechanism by which TOR inhibition exerts these effects, and the extent to which these effects can extend to other models of mitochondrial deficiency, are unknown. Here, we probe the effects of TOR inhibition in a Drosophila model of complex I deficiency. Treatment with rapamycin robustly suppresses the lifespan defect in this model of LS, without affecting behavioral phenotypes. Interestingly, this increased lifespan in response to TOR inhibition occurs in an autophagy-independent manner. Further, we identify a fat storage defect in the ND2 mutant flies that is rescued by rapamycin, supporting a model that rapamycin exerts its effects on mitochondrial disease in these animals by altering metabolism.
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Affiliation(s)
- Adrienne Wang
- University of Washington, Department of Pathology, Seattle, WA, USA
| | - Jacob Mouser
- University of Washington, Department of Pathology, Seattle, WA, USA
| | - Jason Pitt
- University of Washington, Department of Pathology, Seattle, WA, USA
| | - Daniel Promislow
- University of Washington, Department of Pathology, Seattle, WA, USA.,University of Washington, Department of Biology, Seattle, WA, USA
| | - Matt Kaeberlein
- University of Washington, Department of Pathology, Seattle, WA, USA
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14
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Abstract
Mitochondrial disorders represent a major challenge in medicine. Most of the mitochondrial proteins are encoded by the nuclear DNA (nDNA), whereas a very small fraction is encoded by the mitochondrial DNA (mtDNA). Mutations in mtDNA or mitochondria-related nDNA genes can result in mitochondrial dysfunction. The disease usually affects multiple organs in varying locations and severity; however, there are some forms which affect a single organ. The diagnosis of mitochondrial disorders is based on clinical examination, biochemical and histopathologic examinations, functional studies, and molecular genetic testing. Neuropathologic alterations of the muscle are variable and can range from striking abnormalities, such as cytochrome oxidase-negative and ragged red fibers, to nonspecific or minimal changes. Neuropathologic alterations in the brain show common features in disorders with different genetic background. These are characterized by various degrees of vacuolation in the white and gray matter, regional neurodegeneration with reactive astrogliosis, loss of oligodendrocytes, presence of macrophages and microgliosis, capillary proliferation, and mineralization of vessel walls. The advent of molecular genetics, the discovery of biomarkers and new sequencing platforms to perform targeted exome and whole-genome sequencing have changed traditional approaches to diagnose mitochondrial diseases.
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Affiliation(s)
- Maria J Molnar
- Institute of Genomic Medicine, Rare Disorders, Semmelweis University, Budapest, Hungary.
| | - Gabor G Kovacs
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
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15
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Abstract
PURPOSE OF REVIEW Mitochondrial disorders are an increasingly recognized cause of heart dysfunction, with the primary manifestations being cardiomyopathy and conduction defects. This review focuses on the complex genetics of mitochondrial disease and recently discovered conditions that affect mitochondrial function. RECENT FINDINGS Next-generation sequencing techniques, especially whole-exome sequencing, have led to the discovery of a number of conditions that cause mitochondrial dysfunction and subsequent cardiac abnormalities. Nuclear DNA defects are the main cause of mitochondrial disease in children, with disease pathogenesis being related to either abnormalities in specific mitochondrial electron transport chain subunits or in proteins related to subunit or mitochondrial DNA maintenance, mitochondrial protein translation, lipid bilayer structure, or other aspects of mitochondrial function. SUMMARY Currently, symptomatic therapy using standard medications targeting relief of complications is the primary approach to treatment. There are no US Food and Drug Administration-approved therapies for the specific treatment of mitochondrial disease. However, on the basis of recent advances in understanding of the pathophysiology of these complex disorders, various novel approaches are either in clinical trials or in development.
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Affiliation(s)
- Gregory M Enns
- Department of Pediatrics, Stanford University, Stanford, California, USA
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16
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Reinauer C, Meissner T, Roden M, Thon A, Holterhus PM, Haberland H, Binder E, Marg W, Bollow E, Holl R. Reply to: mitochondrial diabetes in Germany and Austria. Eur J Pediatr 2016; 175:2025-2026. [PMID: 27664162 DOI: 10.1007/s00431-016-2784-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 08/29/2016] [Accepted: 09/08/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Christina Reinauer
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.
| | - Thomas Meissner
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), Partner Düsseldorf, 40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD), Partner Ulm, 89081 Ulm, Germany
| | - Michael Roden
- German Center for Diabetes Research (DZD), Partner Düsseldorf, 40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD), Partner Ulm, 89081 Ulm, Germany.,Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.,Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University Düsseldorf, Leibniz Center for Diabetes Research, German Center for Diabetes Research (DZD), 40225, Düsseldorf, Germany
| | - Angelika Thon
- Department of Pediatric Pneumology, Allergology & Neonatology, Children's Hospital, Hannover Medical School, 30625, Hannover, Germany
| | - Paul-Martin Holterhus
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University Hospital Schleswig-Holstein, Christian-Albrechts University Kiel, 24118, Kiel, Germany
| | - Holger Haberland
- Hospital for Children and Adolescents, Sana Hospital Berlin Lichtenberg, 10365, Berlin, Germany
| | - Elisabeth Binder
- Department of Pediatrics, Medical University of Innsbruck, A 6020, Innsbruck, Austria
| | - Wolfgang Marg
- Center for Pediatrics and Adolescent Medicine, Bremen-Mitte Hospital, 28211, Bremen, Germany
| | - Esther Bollow
- Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, German Center for Diabetes Research (DZD), 89081, Ulm, Germany
| | - Reinhard Holl
- Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, German Center for Diabetes Research (DZD), 89081, Ulm, Germany
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17
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El-Hattab AW, Scaglia F. Mitochondrial Cardiomyopathies. Front Cardiovasc Med 2016; 3:25. [PMID: 27504452 PMCID: PMC4958622 DOI: 10.3389/fcvm.2016.00025] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022] Open
Abstract
Mitochondria are found in all nucleated human cells and perform various essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA), whereas more than 99% of them are encoded by nuclear DNA (nDNA). Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs for various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20–40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular non-compaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain complexes subunits and their assembly factors, mitochondrial transfer RNAs, ribosomal RNAs, ribosomal proteins, translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia.
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital , Al-Ain , United Arab Emirates
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine , Houston, TX , USA
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18
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Niyazov DM, Kahler SG, Frye RE. Primary Mitochondrial Disease and Secondary Mitochondrial Dysfunction: Importance of Distinction for Diagnosis and Treatment. Mol Syndromol 2016; 7:122-37. [PMID: 27587988 DOI: 10.1159/000446586] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2016] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial disease refers to a heterogeneous group of disorders resulting in defective cellular energy production due to abnormal oxidative phosphorylation (oxphos). Primary mitochondrial disease (PMD) is diagnosed clinically and ideally, but not always, confirmed by a known or indisputably pathogenic mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) mutation. The PMD genes either encode oxphos proteins directly or they affect oxphos function by impacting production of the complex machinery needed to run the oxphos process. However, many disorders have the 'mitochondrial' phenotype without an identifiable mtDNA or nDNA mutation or they have a variant of unknown clinical significance. Secondary mitochondrial dysfunction (SMD) can be caused by genes encoding neither function nor production of the oxphos proteins and accompanies many hereditary non-mitochondrial diseases. SMD may also be due to nongenetic causes such as environmental factors. In our practice, we see many patients with clinical signs of mitochondrial dysfunction based on phenotype, biomarkers, imaging, muscle biopsy, or negative/equivocal mtDNA or nDNA test results. In these cases, it is often tempting to assign a patient's phenotype to 'mitochondrial disease', but SMD is often challenging to distinguish from PMD. Fortunately, rapid advances in molecular testing, made possible by next generation sequencing, have been effective at least in some cases in establishing accurate diagnoses to distinguish between PMD and SMD. This is important, since their treatments and prognoses can be quite different. However, even in the absence of the ability to distinguish between PMD and SMD, treating SMD with standard treatments for PMD can be effective. We review the latest findings regarding mitochondrial disease/dysfunction and give representative examples in which differentiation between PMD and SMD has been crucial for diagnosis and treatment.
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Affiliation(s)
- Dmitriy M Niyazov
- Department of Pediatrics, Ochsner Clinic Foundation, New Orleans, La, USA
| | - Stephan G Kahler
- Department of Pediatrics, Arkansas Children's Hospital and Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, Ark., USA
| | - Richard E Frye
- Department of Pediatrics, Arkansas Children's Hospital and Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, Ark., USA
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19
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Reinauer C, Meissner T, Roden M, Thon A, Holterhus PM, Haberland H, Binder E, Marg W, Bollow E, Holl R. Low prevalence of patients with mitochondrial disease in the German/Austrian DPV diabetes registry. Eur J Pediatr 2016; 175:613-22. [PMID: 26670026 DOI: 10.1007/s00431-015-2675-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/20/2015] [Accepted: 11/26/2015] [Indexed: 01/21/2023]
Abstract
UNLABELLED The aim of this study was to characterize the phenotype and treatment of young patients (manifestation <30 years) with diabetes of mitochondrial origin (DMO), based on the German/Austrian DPV (Diabetes Patienten Verlaufsdokumentation) registry. Only 13 (0.02 %) of all patients with diabetes in this cohort were identified with DMO, mainly due to the Kearns-Sayre (n = 5), Pearson (n = 3), or mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome (n = 2). The onset of DMO (14.2, interquartile range (IQR) 7.1-16 years) was later than diabetes onset in individuals with T1D but earlier than in T2D. At manifestation, patients exhibited a mild elevation of blood glucose concentrations (251, IQR 178-299 mg/dl) without ketoacidosis. They had lower body mass index (BMI) values (-1.39 ± 0.28 kg/m(2)) than peers with T1D or T2D (p < 0.0001) and higher triglycerides (211, IQR 134-574 mg/dl) than in T1D (p = 0.04) while there was a high rate of dyslipidemia (86 %). Insulin requirements (0.58, IQR 0.37-0.90 U/kg/d) were between T1D and T2D while glucometabolic control (glycated hemoglobin A1c (HbA1c) 7.4 ± 0.52 %) in DMO was comparable to age-matched T2D and stable over a 5-year follow-up. CONCLUSION Primary mitochondrial disorders are a rare cause of juvenile diabetes and likely to be underdiagnosed. As there is clinical overlap with T1D and T2D, dyslipidemia and low body weight may help to identify further DMO cases. WHAT IS KNOWN • In adults diabetes of mitochondrial origin (DMO) is a rare cause of non-autoimmune diabetes, affecting about 0.8 % of diabetes cases. • Common features are a maternal family history of diabetes, hearing loss and neurological abnormalities. What is New: • In our juvenile cohort 0.02 % of diabetes patients (age < 30 years) were affected by DMO, while Kearns Sayre, MELAS and Pearson syndrome were the most frequent entities. • Juvenile DMO patients exhibited dyslipidemia, higher triglycerides and a lower BMI than peers with T1D or T2D, while some patients also showed retinal changes.
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Affiliation(s)
- Christina Reinauer
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.
| | - Thomas Meissner
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.,German Center for Diabetes Research (DZD e.V.), Partners Düsseldorf and Ulm, Düsseldorf, Germany
| | - Michael Roden
- German Center for Diabetes Research (DZD e.V.), Partners Düsseldorf and Ulm, Düsseldorf, Germany.,Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany.,Institute for Clinical Diabetology, German Diabetes Center at Heinrich Heine University Düsseldorf, Leibniz Center for Diabetes Research, German Center for Diabetes Research (DZD), 40225, Düsseldorf, Germany
| | - Angelika Thon
- Department of Pediatric Pneumology, Allergology & Neonatology, Children's Hospital, Hannover Medical School, 30625, Hannover, Germany
| | - Paul-Martin Holterhus
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University Hospital Schleswig-Holstein, Christian-Albrechts University Kiel, 24118, Kiel, Germany
| | - Holger Haberland
- Hospital for Children and Adolescents, Sana Hospital Berlin Lichtenberg, 10365, Berlin, Germany
| | - Elisabeth Binder
- Department of Pediatrics, Medical University of Innsbruck, A 6020, Innsbruck, Austria
| | - Wolfgang Marg
- Center for Pediatrics and Adolescent Medicine, Bremen-Mitte Hospital, 28211, Bremen, Germany
| | - Esther Bollow
- Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, German Center for Diabetes Research (DZD), 89081, Ulm, Germany
| | - Reinhard Holl
- Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, German Center for Diabetes Research (DZD), 89081, Ulm, Germany
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20
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Claiborne AB, English RA, Kahn JP. ETHICS OF NEW TECHNOLOGIES. Finding an ethical path forward for mitochondrial replacement. Science 2016; 351:668-70. [PMID: 26842937 DOI: 10.1126/science.aaf3091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Anne B Claiborne
- Institute of Medicine, U.S. National Academies of Sciences, Engineering, and Medicine, Washington, DC 20001, USA.
| | - Rebecca A English
- Institute of Medicine, U.S. National Academies of Sciences, Engineering, and Medicine, Washington, DC 20001, USA
| | - Jeffrey P Kahn
- Johns Hopkins Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205, USA
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21
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Senger BA, Ward LD, Barbosa-Leiker C, Bindler RC. The Parent Experience of Caring for a Child with Mitochondrial Disease. J Pediatr Nurs 2016; 31:32-41. [PMID: 26453412 DOI: 10.1016/j.pedn.2015.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 08/06/2015] [Accepted: 08/15/2015] [Indexed: 11/20/2022]
Abstract
UNLABELLED Mitochondrial disease is a spectrum of progressive genetic disorders resulting from dysfunctions of cellular metabolism in the mitochondria that greatly compromise the lives of affected individuals, who are often children. PURPOSE This study described the parent experiences unique to caring for a child with mitochondrial disease. METHODS Internet surveys were made available to parents of children with a known mitochondrial disease. Surveys included demographic items and two questionnaires: Parent Experience of Child Illness (PECI) and Pediatric Inventory for Parents (PIP). Descriptive data were collected and correlations calculated to determine relationships between the parent experience and stress. RESULTS The majority of participants (n=231) were mothers (95%) of children with mitochondrial disease around the age of 10 years (M=9.85). Elevated scores were found in parent adjustment illness-related concerns regarding Guilt and Worry (M=2.30, SD=.650), Sorrow and Anger (M=2.09, SD=.730), Long-term Uncertainty (M=2.56, SD=.690), and Emotional Resources (M=2.36, SD=.615). Scores indicated elevated feelings of stress in terms of both difficulty and frequency. Significant correlations (p<0.01) were found between parent illness-related concerns and parenting stress. CONCLUSIONS The results of this study suggest that parents of a child with mitochondrial disease feel a burden of responsibility that exceeds the typical caregiver role, see their child as fragile, and have concerns about their child's future. Identification of these concerns can assist nurses to better meet the needs of these parents and families.
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Affiliation(s)
| | - Linda D Ward
- Washington State University College of Nursing, Spokane, WA
| | | | - Ruth C Bindler
- Washington State University College of Nursing, Spokane, WA
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22
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Tischner C, Wenz T. Keep the fire burning: Current avenues in the quest of treating mitochondrial disorders. Mitochondrion 2015; 24:32-49. [DOI: 10.1016/j.mito.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/18/2015] [Accepted: 06/24/2015] [Indexed: 12/18/2022]
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23
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Mitochondrial Diseases. Rare Dis 2015. [DOI: 10.1007/978-94-017-9214-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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24
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Ruhoy IS, Saneto RP. The genetics of Leigh syndrome and its implications for clinical practice and risk management. APPLICATION OF CLINICAL GENETICS 2014; 7:221-34. [PMID: 25419155 PMCID: PMC4235479 DOI: 10.2147/tacg.s46176] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Leigh syndrome, also referred to as subacute necrotizing encephalomyelopathy, is a severe, early-onset neurodegenerative disorder that is relentlessly progressive and devastating to both the patient and the patient’s family. Attributed to the ultimate failure of the mitochondrial respiratory chain, once it starts, the disease often results in the regression of both mental and motor skills, leading to disability and rapid progression to death. It is a mitochondrial disorder with both phenotypic and genetic heterogeneity. The cause of death is most often respiratory failure, but there are a whole host of complications, including refractory seizures, that may further complicate morbidity and mortality. The symptoms may develop slowly or with rapid progression, usually associated with age of onset. Although the disease is usually diagnosed within the first year of life, it is important to note that recent studies reveal phenotypic heterogeneity, with some patients having evidence of in utero presentation and others having adult-onset symptoms.
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Affiliation(s)
- Ilene S Ruhoy
- Division of Pediatric Neurology, Seattle Children's Hospital/University of Washington, Seattle, WA, USA
| | - Russell P Saneto
- Division of Pediatric Neurology, Seattle Children's Hospital/University of Washington, Seattle, WA, USA
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25
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Hirschvogel K, Matiasek K, Flatz K, Drögemüller M, Drögemüller C, Reiner B, Fischer A. Magnetic resonance imaging and genetic investigation of a case of Rottweiler leukoencephalomyelopathy. BMC Vet Res 2013; 9:57. [PMID: 23531239 PMCID: PMC3614464 DOI: 10.1186/1746-6148-9-57] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 03/14/2013] [Indexed: 11/12/2022] Open
Abstract
Background Leukoencephalomyelopathy is an inherited neurodegenerative disorder that affects the white matter of the spinal cord and brain and is known to occur in the Rottweiler breed. Due to the lack of a genetic test for this disorder, post mortem neuropathological examinations are required to confirm the diagnosis. Leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate levels is a rare, autosomal recessive disorder in humans that was recently described to have clinical features and magnetic resonance imaging (MRI) findings that are similar to the histopathologic lesions that define leukoencephalomyelopathy in Rottweilers. Leukoencephalopathy with brain stem and spinal cord involvement is caused by mutations in the DARS2 gene, which encodes a mitochondrial aspartyl-tRNA synthetase. The objective of this case report is to present the results of MRI and candidate gene analysis of a case of Rottweiler leukoencephalomyelopathy to investigate the hypothesis that leukoencephalomyelopathy in Rottweilers could serve as an animal model of human leukoencephalopathy with brain stem and spinal cord involvement. Case presentation A two-and-a-half-year-old male purebred Rottweiler was evaluated for generalised progressive ataxia with hypermetria that was most evident in the thoracic limbs. MRI (T2-weighted) demonstrated well-circumscribed hyperintense signals within both lateral funiculi that extended from the level of the first to the sixth cervical vertebral body. A neurodegenerative disorder was suspected based on the progressive clinical course and MRI findings, and Rottweiler leukoencephalomyelopathy was subsequently confirmed via histopathology. The DARS2 gene was investigated as a causative candidate, but a sequence analysis failed to identify any disease-associated variants in the DNA sequence. Conclusion It was concluded that MRI may aid in the pre-mortem diagnosis of suspected cases of leukoencephalomyelopathy. Genes other than DARS2 may be involved in Rottweiler leukoencephalomyelopathy and may also be relevant in human leukoencephalopathy with brain stem and spinal cord involvement.
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Affiliation(s)
- Katrin Hirschvogel
- Department of Veterinary Clinical Sciences Ludwig-Maximilians-Universitaet, Neurology Service, Clinic of Small Animal Medicine, Munich, Germany
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