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Orphanet Journal of Rare Diseases Mar 2015Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive disorder of the urea cycle. HHH has a panethnic distribution, with a... (Review)
Review
BACKGROUND
Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive disorder of the urea cycle. HHH has a panethnic distribution, with a major prevalence in Canada, Italy and Japan. Acute clinical signs include intermittent episodes of vomiting, confusion or coma and hepatitis-like attacks. Alternatively, patients show a chronic course with aversion for protein rich foods, developmental delay/intellectual disability, myoclonic seizures, ataxia and pyramidal dysfunction. HHH syndrome is caused by impaired ornithine transport across the inner mitochondrial membrane due to mutations in SLC25A15 gene, which encodes for the mitochondrial ornithine carrier ORC1. The diagnosis relies on clinical signs and the peculiar metabolic triad of hyperammonemia, hyperornithinemia, and urinary excretion of homocitrulline. HHH syndrome enters in the differential diagnosis with other inherited or acquired conditions presenting with hyperammonemia.
METHODS
A systematic review of publications reporting patients with HHH syndrome was performed.
RESULTS
We retrospectively evaluated the clinical, biochemical and genetic profile of 111 HHH syndrome patients, 109 reported in 61 published articles, and two unpublished cases. Lethargy and coma are frequent at disease onset, whereas pyramidal dysfunction and cognitive/behavioural abnormalities represent the most common clinical features in late-onset cases or during the disease course. Two common mutations, F188del and R179* account respectively for about 30% and 15% of patients with the HHH syndrome. Interestingly, the majority of mutations are located in residues that have side chains protruding into the internal pore of ORC1, suggesting their possible interference with substrate translocation. Acute and chronic management consists in the control of hyperammonemia with protein-restricted diet supplemented with citrulline/arginine and ammonia scavengers. Prognosis of HHH syndrome is variable, ranging from a severe course with disabling manifestations to milder variants compatible with an almost normal life.
CONCLUSIONS
This paper provides detailed information on the clinical, metabolic and genetic profiles of all HHH syndrome patients published to date. The clinical phenotype is extremely variable and its severity does not correlate with the genotype or with recorded ammonium/ornithine plasma levels. Early intervention allows almost normal life span but the prognosis is variable, suggesting the need for a better understanding of the still unsolved pathophysiology of the disease.
Topics: Aging; Humans; Hyperammonemia; Mutation; Origin Recognition Complex; Ornithine; Protein Conformation; Urea Cycle Disorders, Inborn
PubMed: 25874378
DOI: 10.1186/s13023-015-0242-9 -
Mitochondrion Jul 2021Cell-free mitochondrial DNA (cf-mtDNA) is a marker of inflammatory disease and a predictor of mortality, but little is known about cf-mtDNA in relation to psychobiology.... (Review)
Review
Cell-free mitochondrial DNA (cf-mtDNA) is a marker of inflammatory disease and a predictor of mortality, but little is known about cf-mtDNA in relation to psychobiology. A systematic review of the literature reveals that blood cf-mtDNA varies in response to common real-world stressors including psychopathology, acute psychological stress, and exercise. Moreover, cf-mtDNA is inducible within minutes and exhibits high intra-individual day-to-day variation, highlighting the dynamic regulation of cf-mtDNA levels. We discuss current knowledge on the mechanisms of cf-mtDNA release, its forms of transport ("cell-free" does not mean "membrane-free"), potential physiological functions, putative cellular and neuroendocrine triggers, and factors that may contribute to cf-mtDNA removal from the circulation. A review of in vitro, pre-clinical, and clinical studies shows conflicting results around the dogma that physiological forms of cf-mtDNA are pro-inflammatory, opening the possibility of other physiological functions, including the cell-to-cell transfer of whole mitochondria. Finally, to enhance the reproducibility and biological interpretation of human cf-mtDNA research, we propose guidelines for blood collection, cf-mtDNA isolation, quantification, and reporting standards, which can promote concerted advances by the community. Defining the mechanistic basis for cf-mtDNA signaling is an opportunity to elucidate the role of mitochondria in brain-body interactions and psychopathology.
Topics: Brain; Cell-Free Nucleic Acids; DNA, Mitochondrial; Humans; Mitochondria; Signal Transduction
PubMed: 33839318
DOI: 10.1016/j.mito.2021.04.002 -
Reviews in Medical Virology Nov 2021Infectious diseases occur worldwide with great frequency in both adults and children, causing 350,000 deaths in 2017, according to the latest World Health Organization... (Review)
Review
Infectious diseases occur worldwide with great frequency in both adults and children, causing 350,000 deaths in 2017, according to the latest World Health Organization reports. Both infections and their treatments trigger mitochondrial interactions at multiple levels: (i) incorporation of damaged or mutated proteins into the complexes of the electron transport chain; (ii) impact on mitochondrial genome (depletion, deletions and point mutations) and mitochondrial dynamics (fusion and fission); (iii) membrane potential impairment; (iv) apoptotic regulation; and (v) generation of reactive oxygen species, among others. Such alterations may result in serious adverse clinical events with considerable impact on the quality of life of the children and could even cause death. Herein, we use a systematic review to explore the association between mitochondrial alterations in paediatric infections including human immunodeficiency virus, cytomegalovirus, herpes viruses, various forms of hepatitis, adenovirus, T-cell lymphotropic virus and influenza. We analyse how these paediatric viral infectious processes may cause mitochondrial deterioration in this especially vulnerable population, with consideration for the principal aspects of research and diagnosis leading to improved disease understanding, management and surveillance.
Topics: Antiviral Agents; Child; Communicable Diseases; DNA, Mitochondrial; Humans; Mitochondria; Pediatrics; Virus Diseases
PubMed: 33792105
DOI: 10.1002/rmv.2232 -
Biomolecules Nov 2023Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular... (Review)
Review
Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular control. There are over 1000 known proteins that either reside within the mitochondria or are transiently associated with it. These mitochondrial proteins represent a functional subcellular protein network (mtProteome) that is encoded by mitochondrial and nuclear genomes and significantly varies between cell types and conditions. In neurons, the high metabolic demand and differential energy requirements at the synapses are met by specific modifications to the mtProteome, resulting in alterations in the expression and functional properties of the proteins involved in energy production and quality control, including fission and fusion. The composition of mtProteomes also impacts the localization of mitochondria in axons and dendrites with a growing number of neurodegenerative diseases associated with changes in mitochondrial proteins. This review summarizes the findings on the composition and properties of mtProteomes important for mitochondrial energy production, calcium and lipid signaling, and quality control in neural cells. We highlight strategies in mass spectrometry (MS) proteomic analysis of mtProteomes from cultured cells and tissue. The research into mtProteome composition and function provides opportunities in biomarker discovery and drug development for the treatment of metabolic and neurodegenerative disease.
Topics: Humans; Proteome; Neurodegenerative Diseases; Proteomics; Mitochondria; Neurons; Mitochondrial Proteins
PubMed: 38002320
DOI: 10.3390/biom13111638 -
Scientific Reports Aug 2016Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus... (Review)
Review
Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus provide insight into the underlying pathogenesis of inherited and acquired mitochondrial diseases. Following a systematic literature review on ultrastructural defects in mitochondrial myopathy, we investigated skeletal muscle biopsies from seven subjects with genetically defined mtDNA mutations. Mitochondrial ultrastructure and morphology were characterized using two complimentary approaches: transmission electron microscopy (TEM) and serial block face scanning EM (SBF-SEM) with 3D reconstruction. Six ultrastructural abnormalities were identified including i) paracrystalline inclusions, ii) linearization of cristae and abnormal angular features, iii) concentric layering of cristae membranes, iv) matrix compartmentalization, v) nanotunelling, and vi) donut-shaped mitochondria. In light of recent molecular advances in mitochondrial biology, these findings reveal novel aspects of mitochondrial ultrastructure and morphology in human tissues with implications for understanding the mechanisms linking mitochondrial dysfunction to disease.
Topics: Aged; Biopsy; DNA, Mitochondrial; Female; Humans; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Middle Aged; Mitochondria, Muscle; Mitochondrial Myopathies; Muscle, Skeletal; Mutation; Young Adult
PubMed: 27506553
DOI: 10.1038/srep30610 -
Journal of Translational Medicine May 2021Mitochondria are essential organelles that provide energy for cellular functions, participate in cellular signaling and growth, and facilitate cell death. Based on their... (Review)
Review
BACKGROUND
Mitochondria are essential organelles that provide energy for cellular functions, participate in cellular signaling and growth, and facilitate cell death. Based on their multifactorial roles, mitochondria are also critical in the progression of critical illnesses. Transplantation of mitochondria has been reported as a potential promising approach to treat critical illnesses, particularly ischemia reperfusion injury (IRI). However, a systematic review of the relevant literature has not been conducted to date. Here, we systematically reviewed the animal and human studies relevant to IRI to summarize the evidence for mitochondrial transplantation.
METHODS
We searched MEDLINE, the Cochrane library, and Embase and performed a systematic review of mitochondrial transplantation for IRI in both preclinical and clinical studies. We developed a search strategy using a combination of keywords and Medical Subject Heading/Emtree terms. Studies including cell-mediated transfer of mitochondria as a transfer method were excluded. Data were extracted to a tailored template, and data synthesis was descriptive because the data were not suitable for meta-analysis.
RESULTS
Overall, we identified 20 animal studies and two human studies. Among animal studies, 14 (70%) studies focused on either brain or heart IRI. Both autograft and allograft mitochondrial transplantation were used in 17 (85%) animal studies. The designs of the animal studies were heterogeneous in terms of the route of administration, timing of transplantation, and dosage used. Twelve (60%) studies were performed in a blinded manner. All animal studies reported that mitochondrial transplantation markedly mitigated IRI in the target tissues, but there was variation in biological biomarkers and pathological changes. The human studies were conducted with a single-arm, unblinded design, in which autologous mitochondrial transplantation was applied to pediatric patients who required extracorporeal membrane oxygenation (ECMO) for IRI-associated myocardial dysfunction after cardiac surgery.
CONCLUSION
The evidence gathered from our systematic review supports the potential beneficial effects of mitochondrial transplantation after IRI, but its clinical translation remains limited. Further investigations are thus required to explore the mechanisms of action and patient outcomes in critical settings after mitochondrial transplantation. Systematic review registration The study was registered at UMIN under the registration number UMIN000043347.
Topics: Animals; Cell Death; Child; Humans; Mitochondria; Reperfusion Injury
PubMed: 34001191
DOI: 10.1186/s12967-021-02878-3 -
Frontiers in Aging Neuroscience 2023Many lines of evidence suggest that mitochondria have a central role in aging-related neurodegenerative diseases, such as Alzheimer's disease (AD). Mitochondrial...
Many lines of evidence suggest that mitochondria have a central role in aging-related neurodegenerative diseases, such as Alzheimer's disease (AD). Mitochondrial dysfunction, cerebral energy dysmetabolism and oxidative damage increase with age, and are early event in AD pathophysiology and may precede amyloid beta (Aβ) plaques. probes of mitochondrial function and energy metabolism are therefore crucial to characterize the bioenergetic abnormalities underlying AD risk, and their relationship to pathophysiology and cognition. A majority of the research conducted in humans have used F-fluoro-deoxygluose (FDG) PET to image cerebral glucose metabolism (CMRglc), but key information regarding oxidative phosphorylation (OXPHOS), the process which generates 90% of the energy for the brain, cannot be assessed with this method. Thus, there is a crucial need for imaging tools to measure mitochondrial processes and OXPHOS in the human brain. Phosphorus-magnetic resonance spectroscopy (P-MRS) is a non-invasive method which allows for the measurement of OXPHOS-related high-energy phosphates (HEP), including phosphocreatine (PCr), adenosine triphosphate (ATP), and inorganic phosphate (Pi), in addition to potential of hydrogen (pH), as well as components of phospholipid metabolism, such as phosphomonoesters (PMEs) and phosphodiesters (PDEs). Herein, we provide a systematic review of the existing literature utilizing the P-MRS methodology during the normal aging process and in patients with mild cognitive impairment (MCI) and AD, with an additional focus on individuals at risk for AD. We discuss the strengths and limitations of the technique, in addition to considering future directions toward validating the use of P-MRS measures as biomarkers for the early detection of AD.
PubMed: 37273652
DOI: 10.3389/fnagi.2023.1183228 -
Biomedicine & Pharmacotherapy =... Sep 2023Neurodegenerative diseases (NDDs) encompass a range of conditions that involve progressive deterioration and dysfunction of the nervous system. Some of the common NDDs... (Review)
Review
Neurodegenerative diseases (NDDs) encompass a range of conditions that involve progressive deterioration and dysfunction of the nervous system. Some of the common NDDs include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Although significant progress has been made in understanding the pathological mechanisms of NDDs in recent years, the development of targeted and effective drugs for their treatment remains challenging. Kaempferol is a flavonoid whose derivatives include kaempferol-O-rhamnoside, 3-O-β-rutinoside/6-hydroxykaempferol 3,6-di-O-β-d-glucoside, and kaempferide. Emerging studies have suggested that kaempferol and its derivatives possess neuroprotective properties and may have potential therapeutic benefits in NDDs. Here, we aimed to provide a theoretical basis for the use of kaempferol and its derivatives in the clinical treatment of NDDs. We systematically reviewed the literature in the PubMed, Web of Science, and Science Direct databases until June 2022 using the search terms "kaempferol," "kaempferol derivatives," "NDDs," "pharmacokinetics," and "biosynthesis" according to the reporting items for systematic review (PRISMA) standard. Based on combined results of in vivo and in vitro studies, we summarize the basic mechanisms and targets of kaempferol and its derivatives in the management of AD, PD, HD, and ALS. Kaempferol and its derivatives exert a neuroprotective role mainly by preventing the deposition of amyloid fibrils (such as Aβ, tau, and α-synuclein), inhibiting microglia activation, reducing the release of inflammatory factors, restoring the mitochondrial membrane to prevent oxidative stress, protecting the blood-brain barrier, and inhibiting specific enzyme activities (such as cholinesterase). Kaempferol and its derivatives are promising natural neuroprotective agents. By determining their pharmacological mechanism, kaempferol and its derivatives may be new candidate drugs for the treatment of NDDs.
Topics: Humans; Neurodegenerative Diseases; Neuroprotective Agents; Amyotrophic Lateral Sclerosis; Kaempferols; Alzheimer Disease; Parkinson Disease; Huntington Disease
PubMed: 37494786
DOI: 10.1016/j.biopha.2023.115215 -
The Cochrane Database of Systematic... 2003Dementia is a common mental health problem affecting 5% of those over 65. Various pathological processes are linked to memory impairment in dementia, particularly those... (Review)
Review
BACKGROUND
Dementia is a common mental health problem affecting 5% of those over 65. Various pathological processes are linked to memory impairment in dementia, particularly those affecting the cholinergic neurotransmitter system. Acetyl-l-carnitine (ALC) is derived from carnitine and is described as having several properties which may be beneficial in dementia. This includes activity at cholinergic neurons, membrane stabilization and enhancing mitochondrial function. Work on the effects of ALC has been ongoing since the 1980s yet the efficacy of ALC in cognitive decline remains unclear. Early studies suggested a beneficial effect of ALC on cognition and behaviour in aging subjects. However, later, larger studies have not supported these findings. Some of the difficulties lie in the early and later studies differing widely in methodology and assessment tools used, and are therefore difficult to compare. ALC is not currently in routine clinical use.
OBJECTIVES
The objective of this review is to establish whether Acetyl-l-carnitine is clinically effective in the treatment of people with dementia.
SEARCH STRATEGY
The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 8 January 2003 using the terms acetyl-l-carnitine, l-carnitine acetyl ester, acetylcarnitine.
SELECTION CRITERIA
All double-blind, randomized, trials involving people with dementia in which treatment with ALC was compared with a placebo group
DATA COLLECTION AND ANALYSIS
Data were extracted by a reviewer (SH) and entered into Revman 4.1 software. Where possible intention-to-treat data were used, but most of the analyses were of completers (people who completed the study).
MAIN RESULTS
There are 11 included trials, all of which had restricted the participants to people with Alzheimer's disease. All trials assessed the cognitive effects of ALC and in addition six considered severity of dementia, six considered functional ability and six considered clinical global impression. There were statistically significant treatment effects in favour of ALC at 12 and 24 weeks for the numbers showing improvement as determined by Clinical Global Impression, [OR 2.33, 95% CI 1.25 to 4.35, P<0.01] and [OR 3.91, 95% CI 1.32 to 11.54, P=0.01] but not as determined by the CIGIC at 52 weeks. There was no evidence of benefit for ALC in the areas of cognition, severity of dementia, functional ability or Clinical Global Impression as a continuous measure. Various adverse events were reported, but from the meta-analyses there were no statistically significant differences between treated and placebo groups.
REVIEWER'S CONCLUSIONS
There is evidence for benefit of ALC on clinical global impression, but there was no evidence using objective assessments in any other area of outcome. Given the large number of comparisons made, the statistically significant result may be due to chance. At present there is no evidence to recommend its routine use in clinical practice. Although the intention of the review was to access ALC for the treatment of all dementias, the included trials had confined themselves to participants with Alzheimer's disease. Individual patient data may add to the findings, as would trials including other types of dementia and other outcomes (e.g. mood and caregiver quality of life). However, the evidence does not suggest that ALC is likely to prove an important therapeutic agent. More work on the pharmacokinetics of ALC in humans is also required.
Topics: Acetylcarnitine; Aged; Alzheimer Disease; Dementia; Humans; Nootropic Agents; Randomized Controlled Trials as Topic
PubMed: 12804452
DOI: 10.1002/14651858.CD003158 -
Frontiers in Molecular Neuroscience 2021This systematic review sought to determine the effects of Mitochondrial division inhibitor-1 (Mdivi-1) on neural mitochondrial dysfunction and neural... (Review)
Review
Effects of Mdivi-1 on Neural Mitochondrial Dysfunction and Mitochondria-Mediated Apoptosis in Ischemia-Reperfusion Injury After Stroke: A Systematic Review of Preclinical Studies.
This systematic review sought to determine the effects of Mitochondrial division inhibitor-1 (Mdivi-1) on neural mitochondrial dysfunction and neural mitochondria-mediated apoptosis in ischemia/reperfusion (I/R) injury after ischemic stroke. Pubmed, Web of Science, and EMBASE databases were searched through July 2021. The studies published in English language that mentioned the effects of Mdivi-1 on neural mitochondrial dysfunction and neural mitochondria-mediated apoptosis in I/R-induced brain injury were included. The CAMARADES checklist (for studies) and the TOXRTOOL checklist (for studies) were used for study quality evaluation. Twelve studies were included (median CAMARADES score = 6; TOXRTOOL scores ranging from 16 to 18). All studies investigated neural mitochondrial functions, providing that Mdivi-1 attenuated the mitochondrial membrane potential dissipation, ATP depletion, and complexes I-V abnormalities; enhanced mitochondrial biogenesis, as well as inactivated mitochondrial fission and mitophagy in I/R-induced brain injury. Ten studies analyzed neural mitochondria-mediated apoptosis, showing that Mdivi-1 decreased the levels of mitochondria-mediated proapoptotic factors (AIF, Bax, cytochrome , caspase-9, and caspase-3) and enhanced the level of antiapoptotic factor (Bcl-2) against I/R-induced brain injury. The findings suggest that Mdivi-1 can protect neural mitochondrial functions, thereby attenuating neural mitochondria-mediated apoptosis in I/R-induced brain injury. Our review supports Mdivi-1 as a potential therapeutic compound to reduce brain damage in ischemic stroke (PROSPERO protocol registration ID: CRD42020205808). [https://www.crd.york.ac.uk/prospero/], identifier [CRD42020205808].
PubMed: 35002619
DOI: 10.3389/fnmol.2021.778569