Mitochondrial Dysfunction In Patients Research Articles

Mitochondrial dysfunction in patients with respiratory diseases

The aim of this scientific literature review was to find new solutions to urgent problems of treating respiratory diseases and reducing the associated temporary loss of ability to work and disability. The article presents the results of the analysis of 62 scientific papers published over 23 years (2001 – 2023) on mitochondrial dysfunction (MD), new methods of its diagnosis, and ways of its correction in respiratory diseases. Disorder of the energy function of mitochondria has been identified as an urgent scientific problem of respiratory medicine. It is noted that new methods of pathogenetic therapy for common and currently difficult-to-treat diseases are being developed to solve this problem. The key section of the review is devoted to the results of studies of mitochondrial dysfunction in patients with asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and pulmonary hypertension.Conclusion. The article assesses MD diagnostic methods that are potentially applicable in real clinical practice. The results of studying the electric potential of the inner mitochondrial membrane, accumulation of active forms of oxygen, production of adenosine triphosphate in blood cells, alveocytes and epithelium of the respiratory tract, as well as bronchial smooth muscle cells, endothelium and vascular smooth muscle cells in the pulmonary artery system, determination of mitochondrial DNA in biological environments are compared. Proposed methods for the correction of MD syndrome in the clinical picture of respiratory diseases are briefly covered.

Increased BNIP3 activity contributes to mitochondrial dysregulation: A hypothesis on the mechanism of ineffective erythropoiesis in β-thalassemia

Ineffective erythropoiesis (IE) and the premature destruction of erythroblasts play important roles in the pathophysiology of β-thalassemia. Accumulating evidence suggests that the pathology of IE is associated with multiple factors, including apoptosis and reactive oxygen species (ROS) generation. A previous study also indicated that dysregulation of mitochondrial homeostasis and autophagy contributes to IE in the bone marrow of β-thalassemia patients. However, the precise molecular mechanism underlying mitochondria-mediated IE remains poorly understood. Here, we propose that the increased activity of adenovirus E1B 19-kDa-interacting protein 3 (BNIP3) promotes mitochondrial fragmentation, autophagy, and apoptosis of erythroid progenitors in β-thalassemia. The present hypothesis is based on the published literature showing that 1) BNIP3 is involved in mitochondrial dysfunction and autophagy, 2) BNIP3 expression is regulated by p53 and hypoxia-inducible factor-1α, and 3) BNIP3 expression can be attenuated by a number of approaches. Our hypothesis can be verified through both in vitro and in vivo experiments. BNIP3 could be a promising therapeutic target for minimizing the pathophysiology of IE and reducing ROS generation associated with mitochondrial dysfunction in patients with β-thalassemia.

The role of mitochondrial dysfunction in the stabilization of the glaucomatous process

This study determines the extent of mitochondrial dysfunction in patients with primary open-angle glaucoma (POAG) and evaluates the potential for stabilizing the glaucomatous process by improving mitochondrial functional activity and energy production by therapy with Mexidol and Mexidol FORTE 250. The study included 80 patients with moderate POAG with compensated intraocular pressure and 20 healthy volunteers. The extent of mitochondrial dysfunction was assessed by measuring the activity levels of mitochondrial enzymes: succinate dehydrogenase (SDH) and α-glycerophosphate dehydrogenase (α-GPDH) in peripheral blood lymphocytes using cytochemical analysis and cytometric morphology and density analysis (cytomorphodensitometry). Patients in the main group received sequential therapy with Mexidol as follows: Mexidol solution for intravenous and intramuscular administration at 50 mg/ml, 300 mg daily intramuscularly for 14 days, followed by Mexidol FORTE 250 tablets, one tablet three times daily for 56 days. Stabilization of glaucomatous optic neuropathy during treatment was evaluated using a comprehensive set of perimetric, electrophysiological, and structural-topographical methods at 14, 56, and 90 days. Sequential therapy in the main group resulted in a significant increase in mitochondrial enzyme activity at 14 and 56 days compared to baseline, with a gradual regression by the end of the observation period (90 days). This was accompanied by an increase in the number of mitochondria and an increase in their optical density as measured by cytomorphodensitometry. The improvement in mitochondrial enzyme activity at 14 and 56 days was associated with positive changes in the structural and functional parameters of the retina, as evidenced by static perimetry, optical coherence tomography, and a series of electrophysiological tests. The obtained data can be used to optimize POAG therapy by reducing mitochondrial dysfunction and stabilizing glaucomatous optic neuropathy.

Skeletal Muscle Mitochondrial Dysfunction in Patients with CKD and Heart Failure (HF)

Skeletal Muscle Mitochondrial Dysfunction in Patients with CKD and Heart Failure (HF)

SIRT5 rs12216101 T>G variant is associated with liver damage and mitochondrial dysfunction in patients with non-alcoholic fatty liver disease

Sirtuin 5, encoded by the SIRT5 gene, is a NAD+-dependent deacylase that modulates mitochondrial metabolic processes through post-translational modifications. In this study, we aimed to examine the impact of the SIRT5 rs12216101T>G non-coding single nucleotide polymorphism on disease severity in patients with non-alcoholic fatty liver disease (NAFLD). The rs12216101 variant was genotyped in 2,606 consecutive European patients with biopsy-proven NAFLD. Transcriptomic analysis, expression of mitochondrial complexes and oxidative stress levels were measured in liver samples from a subset of bariatric patients. Effects of SIRT5 pharmacological inhibition were evaluated in HepG2 cells exposed to excess free fatty acids. Mitochondrial energetics invitro were investigated by high-performance liquid chromatography. In the whole cohort, the frequency distribution of SIRT5 rs12216101 TT, TG and GG genotypes was 47.0%, 42.3% and 10.7%, respectively. At multivariate logistic regression analysis adjusted for sex, age >50 years, diabetes, and PNPLA3 rs738409 status, the SIRT5 rs12216101T>G variant was associated with the presence of non-alcoholic steatohepatitis (odds ratio 1.20, 95% CI 1.03-1.40) and F2-F4 fibrosis (odds ratio 1.18; 95% CI 1.00-1.37). Transcriptomic analysis showed that the SIRT5 rs12216101T>G variant was associated with upregulation of transcripts involved in mitochondrial metabolic pathways, including the oxidative phosphorylation system. In patients carrying the G allele, western blot analysis confirmed an upregulation of oxidative phosphorylation complexes III, IV, V and consistently higher levels of reactive oxygen species, reactive nitrogen species and malondialdehyde, and lower ATP levels. Administration of a pharmacological SIRT5 inhibitor preserved mitochondrial energetic homeostasis in HepG2 cells, as evidenced by restored ATP/ADP, NAD+/NADH, NADP+/NADPH ratios and glutathione levels. The SIRT5 rs12216101T>G variant, heightening SIRT5 activity, is associated with liver damage, mitochondrial dysfunction, and oxidative stress in patients with NAFLD. In this study we discovered that the SIRT5 rs12216101T>G variant is associated with higher disease severity in patients with non-alcoholic fatty liver disease (NAFLD). This risk variant leads to a SIRT5 gain-of-function, enhancing mitochondrial oxidative phosphorylation and thus leading to oxidative stress. SIRT5 may represent a novel disease modulator in NAFLD.

FRI029 Chronic Free Fatty Acid Elevation Is Associated With An Overcompensatory Increase In Hepatic Mitochondrial Function In Patients With Overweight Or Obesity

Abstract Disclosure: F. Bril: None. S. Kalavalapalli: None. K. Cusi: None. The obesity epidemic has resulted in a significant increase in the prevalence of nonalcoholic fatty liver disease (NAFLD). Some patients with NAFLD progress to more severe forms of the disease, such as nonalcoholic steatohepatitis (NASH) and cirrhosis. Our central hypothesis is that the inability of hepatic mitochondria to enhance nutrient oxidation in the setting of nutrient oversupply plays a key role in the progression of NAFLD. Specifically, the aim of this study was to assess if free fatty acid (FFA) excess contributes to hepatic mitochondrial dysfunction in patients with overweight or obesity. Patients with BMI ≥ 25kg/m2, without diabetes were included in the study. Patients underwent a 2-hour oral glucose tolerance test (OGTT) and a liver proton magnetic resonance spectroscopy (1H-MRS) to measure liver fat. In vivo hepatic mitochondrial ATP levels were measured by phosphorus (31P)-MRS every 30 minutes during a 2-hour oral fructose challenge (OFC). Due to unregulated phosphorylation of fructose upon entering hepatocytes, the OFC provides a dynamic measurement of hepatic ATP consumption and re-synthesis. Hepatic ATP levels were estimated as β-ATP/total phosphorus. A total of 37 patients were recruited for this study (age: 54 ± 11 years; sex: 43% male/57% female; BMI: 34.4 ± 6.3 kg/m2; A1c: 5.7 ± 0.4%; NAFLD: 51%). No differences were found in hepatic ATP levels in patients with or without NAFLD (0.019 ± 0.015 vs. 0.016 ± 0.012, p=0.44). Patients were then divided in three groups (tertiles) based on fasting FFA levels. We did not observe any significant differences among these three groups in key clinical variables, such as age, sex, BMI, A1c or prevalence of NAFLD. At baseline (pre OFC), we did not observe any difference in hepatic ATP levels (i.e., β-ATP/total phosphorus) among FFA tertiles (0.020 ± 0.015, 0.020 ± 0.012, and 0.012 ± 0.012, p=0.25). During the OFC, we estimated changes over time in hepatic ATP levels as the decremental area under the curve (AUROC) of β-ATP/total phosphorus. We observed that the decremental AUROC of hepatic ATP levels during OFC was significantly different among groups (0.57 ± 0.86, 0.14 ± 0.59, -0.40 ± 0.54, p=0.006). Patients in the highest tertile of FFAs showed no consumption of ATP after the OFC, but rather an overall increase in ATP AUROC over time. Plasma FFA levels correlated well with hepatic ATP AUROC during the OFC (-0.47, p =0.007). Conclusion: Chronic elevations in FFA levels are associated with changes in hepatic mitochondrial ATP synthesis, which were unmasked after an oral fructose challenge. While long-term, FFA elevations may impair mitochondrial function, in our study we observed an overcompensatory response in patients with high plasma FFA, characterized by an increase in hepatic ATP levels over time after fructose consumption. At what point this compensation is overwhelmed leading to inflammation and cellular lipotoxicity remains to be determined. Presentation: Friday, June 16, 2023

P333 Clinical, pathological heterogeneity and mitochondrial dysfunction in patients with anti-mitochondrial antibodies related myositis

P333 Clinical, pathological heterogeneity and mitochondrial dysfunction in patients with anti-mitochondrial antibodies related myositis

Neuroinflammation and Mitochondrial Dysfunction in Parkinson's Disease: Connecting Neuroimaging with Pathophysiology.

There is a pressing need for disease-modifying therapies in patients suffering from neurodegenerative diseases, including Parkinson's disease (PD). However, these disorders face unique challenges in clinical trial designs to assess the neuroprotective properties of potential drug candidates. One of these challenges relates to the often unknown individual disease mechanisms that would, however, be relevant for targeted treatment strategies. Neuroinflammation and mitochondrial dysfunction are two proposed pathophysiological hallmarks and are considered to be highly interconnected in PD. Innovative neuroimaging methods can potentially help to gain deeper insights into one's predominant disease mechanisms, can facilitate patient stratification in clinical trials, and could potentially map treatment responses. This review aims to highlight the role of neuroinflammation and mitochondrial dysfunction in patients with PD (PwPD). We will specifically introduce different neuroimaging modalities, their respective technical hurdles and challenges, and their implementation into clinical practice. We will gather preliminary evidence for their potential use in PD research and discuss opportunities for future clinical trials.

Heart failure in patients is associated with downregulation of mitochondrial quality control genes.

Mitochondrial dysfunction is one of key factors causing heart failure. We performed a comprehensive analysis of expression of mitochondrial quality control (MQC) genes in heart failure. Myocardial samples were obtained from patients with ischemic and dilated cardiomyopathy in a terminal stage of heart failure and donors without heart disease. Using quantitative real-time PCR, we analysed a total of 45 MQC genes belonging to mitochondrial biogenesis, fusion-fission balance, mitochondrial unfolded protein response (UPRmt), translocase of the inner membrane (TIM) and mitophagy. Protein expression was analysed by ELISA and immunohistochemistry. The following genes were downregulated in ischemic and dilated cardiomyopathy: COX1, NRF1, TFAM, SIRT1, MTOR, MFF, DNM1L, DDIT3, UBL5, HSPA9, HSPE1, YME1L, LONP1, SPG7, HTRA2, OMA1, TIMM23, TIMM17A, TIMM17B, TIMM44, PAM16, TIMM22, TIMM9, TIMM10, PINK1, PARK2, ROTH1, PARL, FUNDC1, BNIP3, BNIP3L, TPCN2, LAMP2, MAP1LC3A and BECN1. Moreover, MT-ATP8, MFN2, EIF2AK4 and ULK1 were downregulated in heart failure from dilated, but not ischemic cardiomyopathy. VDAC1 and JUN were only genes that exhibited significantly different expression between ischemic and dilated cardiomyopathy. Expression of PPARGC1, OPA1, JUN, CEBPB, EIF2A, HSPD1, TIMM50 and TPCN1 was not significantly different between control and any form of heart failure. TOMM20 and COX proteins were downregulated in ICM and DCM. Heart failure in patients with ischemic and dilated cardiomyopathy is associated with downregulation of large number of UPRmt, mitophagy, TIM and fusion-fission balance genes. This indicates multiple defects in MQC and represents one of potential mechanisms underlying mitochondrial dysfunction in patients with heart failure.

Biallelic variants in COQ7 cause distal hereditary motor neuropathy with upper motor neuron signs.

COQ7 encodes a hydroxylase responsible for the penultimate step of coenzyme Q10 (CoQ10) biosynthesis in mitochondria. CoQ10 is essential for multiple cellular functions, including mitochondrial oxidative phosphorylation, lipid metabolism, and reactive oxygen species homeostasis. Mutations in COQ7 have been previously associated with primary CoQ10 deficiency, a clinically heterogeneous multisystemic mitochondrial disorder. We identified COQ7 biallelic variants in nine families diagnosed with distal hereditary motor neuropathy with upper neuron involvement, expending the clinical phenotype associated with defects in this gene. A recurrent p.Met1? change was identified in five families from Brazil with evidence of a founder effect. Fibroblasts isolated from patients revealed a substantial depletion of COQ7 protein levels, indicating protein instability leading to loss of enzyme function. High-performance liquid chromatography assay showed that fibroblasts from patients had reduced levels of CoQ10, and abnormal accumulation of the biosynthetic precursor DMQ10. Accordingly, fibroblasts from patients displayed significantly decreased oxygen consumption rates in patients, suggesting mitochondrial respiration deficiency. Induced pluripotent stem cell-derived motor neurons from patient fibroblasts showed significantly increased levels of extracellular neurofilament light protein, indicating axonal degeneration. Our findings indicate a molecular pathway involving CoQ10 biosynthesis deficiency and mitochondrial dysfunction in patients with distal hereditary motor neuropathy. Further studies will be important to evaluate the potential benefits of CoQ10 supplementation in the clinical outcome of the disease.

Chronic kidney disease exacerbates ischemic leg myopathy in patients with peripheral artery disease

Introduction: Patients with peripheral artery disease (PAD) present with one or more comorbid risk factors that accelerate disease evolution and worsen clinical outcomes. Notably, PAD patients with chronic kidney disease (CKD) have greater risk for major adverse limb events and mortality; The objective of this study was to determine the impact of CKD on skeletal muscle strength and mitochondrial health in patients with and without PAD. Methods: We performed a cross-sectional analysis of skeletal muscle strength and mitochondrial health in four groups of patients (79 males and 21 females, 65.6±10.0 years old): PAD only (Toe brachial index, TBI<0.5 and eGFR>60 mL/min), CKD only (TBI>0.75 and eGFR:15-45 mL/min), PAD with CKD (TBI<0.5 and eGFR:15-45 mL/min), and adult controls without PAD and CKD (TBI>0.75 and eGFR>60 mL/min). Maximal isometric plantar flexor strength was measured using a force dynamometer. Gastrocnemius muscle biopsies were obtained for comprehensive mitochondrial diagnostics. Results: Plantar flexor muscle strength was lowest in PAD patients with CKD, which had a significant difference from adult controls (PAD+CKD: 161.1±53.3 N vs. Control: 272.9±70.0 N, P<0.01), a trending difference ( P=0.08) from PAD patients without CKD (238.8±81.0 N), and no difference ( P=0.20) from CKD patients (231.7±79.5 N). Analysis of mitochondrial oxidative phosphorylation (OXPHOS) revealed that both CKD and PAD with CKD groups had significant reduction (30~40%) in mitochondrial bioenergetic function ( JO2) at various levels of energy demand mimicking from resting skeletal muscle to maximal contraction compared with adult controls and PAD without CKD group (P<0.05). Similarly, OXPHOS conductance was significantly reduced in the PAD with CKD group compared with both adult controls and PAD patients without CKD (PAD+CKD: 1.4±0.5 vs. Control: 2.5±1.0 and PAD: 2.6±0.8, P<0.01). Surprisingly, patients with CKD only had lower OXPHOS conductance (1.7±0.6) compared to adult controls ( P=0.05) and patients with PAD only ( P=0.02). Interestingly, PAD patients without CKD had no difference in mitochondrial function compared with adult controls ( P=0.98). Conclusion: Taken together, the results suggest that CKD plays a critical role in exacerbating skeletal myopathy determined by muscle weakness and mitochondrial dysfunction in patients with PAD. Evidence from this study suggests that mitochondrial dysfunction may be a primary site of convergence of these two diseases. Funding source: National Institutes of Health grant R01HL149704 and American Heart Association grant POST903198. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

SIRT5 rs12216101 T>G variant is associated with oxidative stress and mitochondrial dysfunction in patients with non-alcoholic fatty liver disease

SIRT5 rs12216101 T>G variant is associated with oxidative stress and mitochondrial dysfunction in patients with non-alcoholic fatty liver disease

Iron- and Neuromelanin-Weighted Neuroimaging to Study Mitochondrial Dysfunction in Patients with Parkinson's Disease.

The underlying causes of Parkinson's disease are complex, and besides recent advances in elucidating relevant disease mechanisms, no disease-modifying treatments are currently available. One proposed pathophysiological hallmark is mitochondrial dysfunction, and a plethora of evidence points toward the interconnected nature of mitochondria in neuronal homeostasis. This also extends to iron and neuromelanin metabolism, two biochemical processes highly relevant to individual disease manifestation and progression. Modern neuroimaging methods help to gain in vivo insights into these intertwined pathways and may pave the road to individualized medicine in this debilitating disorder. In this narrative review, we will highlight the biological rationale for studying these pathways, how distinct neuroimaging methods can be applied in patients, their respective limitations, and which challenges need to be overcome for successful implementation in clinical studies.

Peripheral blood mononuclear cell mitochondrial copy number and adenosine triphosphate inhibition test in NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is associated with mitochondrial dysfunction. This study aims to develop biomarkers for assessing mitochondrial dysfunction in patients with NAFLD. Mitochondrion-associated transcriptome analysis was performed. Peripheral blood mononuclear cells obtained from patients with NAFLD (69) and healthy controls (19) were used to determine the mitochondrial DNA (mtDNA) copy number. A mitochondrial inhibition substrate test (ATP assay) was performed in HepG2 cells using the patient serum. Hepatic mRNA transcriptome analysis showed that the gene expression related to mitochondrial functions (mitochondrial fusion, apoptotic signal, and mitochondrial envelope) increased in patients with steatohepatitis, but not in those with NAFL. Gene set enrichment analysis revealed that the upregulated expression of genes is related to the pathways of the tricarboxylic (TCA) cycle and deoxyribonucleic acid (DNA) replication in patients with steatohepatitis, but not in healthy controls. The mtDNA copy number in the peripheral blood mononuclear cells was 1.28-fold lower in patients with NAFLD than that in healthy controls (P <.0001). The mitochondrial inhibition substrate test showed that the cellular adenosine triphosphate (ATP) concentration was 1.2-fold times less in NAFLD patients than that in healthy controls (P <.0001). The mtDNA copy number and mitochondrial ATP inhibition substrate test demonstrated negative correlations with the degree of hepatic steatosis, whereas the ATP concentration showed a positive correlation with the mtDNA copy number. The mitochondrial copy number of peripheral blood mononuclear cells and mitochondrial ATP inhibition substrate can be used as biomarkers for assessing the mitochondrial dysfunction in patients with NAFLD.

Urolithin A attenuates auditory cell senescence by activating mitophagy

Aging of sensory organs is associated with a decline in mitochondrial function and the accumulation of dysfunctional mitochondria. Impaired mitophagy blocks the turnover of dysfunctional mitochondria and leads to their accumulation. Urolithin A (UA) induces mitophagy in various mammalian cells. This study was aimed at investigating the effect of the mitophagy activator, UA, on premature senescent auditory cells. The levels of cellular senescence-associated p53 and p21 significantly increased in H2O2-induced senescent House Ear Institute‐Organ of Corti 1 (HEI-OC1) cells and cochlear explants. However, the levels of mitophagy-related molecules significantly decreased. UA significantly decreased the expression of senescence-associated p53 and p21, and increased the expression of mitophagy-related proteins, in H2O2-induced senescent cells and cochlear explants. The percentage of β-galactosidase-stained senescent cells also reduced in H2O2-treated cells and cochlear explants upon UA pre-treatment. The formation of mitophagosomes and mitophagolysosomes was restored upon UA pre-treatment of H2O2-induced senescent cells. The knockdown of mitophagy-related genes (Parkin and Bnip3) resulted in annulment of UA-induced anti-senescent activity. UA significantly increased the ATP content, mitochondrial DNA (mtDNA) integrity, and mitochondrial membrane potential in senescent HEI-OC1 cells. These findings indicate that UA counteracted mitophagy decline and prevented premature senescence in auditory cells. Hence, UA administration might be a promising strategy for preventing mitochondrial dysfunction in patients with age-related hearing loss.

LXR activation ameliorates high glucose stress-induced aberrant mitochondrial dynamics via downregulation of Calpain1 expression in H9c2 cardiomyoblasts

Liver-X-receptor (LXR) has previously been shown to exert a cardioprotective effect against the development of diabetic cardiomyopathy (DCM) associated with a reduction in mitochondrial dysfunction. However, the underlying mechanism by which LXR activation attenuates the structural and functional mitochondrial impairments caused by high glucose (HG) stress remains unclear. We demonstrate here that LXR activation inhibits HG stress-induced mitochondrial dysfunction and ameliorates aberrant mitochondrial dynamics. Furthermore, LXR activation regulates mitochondrial dynamics by inhibiting HG stress-induced upregulation of Calpain1 expression. These data indicate that amelioration of Calpain1-mediated aberrant mitochondrial dynamics may be at least part of the mechanism underlying the cardioprotective effects of LXR against HG stress. Therefore, LXR is a potentially attractive molecular target for treating cardiac mitochondrial dysfunction in patients with diabetes.

The Pattern of Retinal Ganglion Cell Loss in Wolfram Syndrome is Distinct From Mitochondrial Optic Neuropathies

To describe the clinical phenotype of a cohort of patients with Wolfram syndrome (WS), focusing on the pattern of optic atrophy correlated with brain magnetic resonance imaging (MRI) measurements, as compared with patients with OPA1-related dominant optic atrophy (DOA). Retrospective, comparative cohort study. We reviewed 25 patients with WS and 33 age-matched patients affected by OPA1-related DOA. Ophthalmologic, neurologic, endocrinologic, and MRI data from patients with WS were retrospectively retrieved. Ophthalmologic data were compared with data from patients with OPA1-related DOA and further analyzed for age dependency dividing patients in age quartiles. In a subgroup of patients with WS, we correlated the structural damage assessed by optical coherence tomography (OCT) with brain MRI morphologic measurements. Visual acuity (VA), visual field mean defect (MD), retinal nerve fiber layer (RNFL), and ganglion cell layer (GCL) thickness were assessed by OCT and MRI morphologic measurements of anterior and posterior visual pathways. Optic atrophy was present in 100% of patients with WS. VA, MD, and RNFL thickness loss were worse in patients with WS with a faster decline since early age as compared with patients with DOA, who displayed a more stable visual function over the years. Conversely, GCL sectors were overall thinner in patients with DOA since early age compared to patients with WS, in which GCL thickness started to decline later in life. The neuroradiologic subanalysis on 11 patients with WS exhibited bilateral thinning of the anterior optic pathway, especially the prechiasmatic optic nerves and optic tracts. Optic tract thinning was significantly correlated with GCL thickness but not with RNFL parameters. Our results showed a generally more severe and diffuse degeneration of both anterior and posterior visual pathways in patients with WS, with fast deterioration of visual function and structural OCT parameters since early age. The pattern observed with OCT suggests that retinal ganglion cell axonal degeneration (ie, RNFL) precedes cellular body atrophy (ie, GCL) by about a decade. This differs substantially from DOA, in which a more stable visual function is evident with predominant early loss of GCL, indirectly supporting the lack of a primary mitochondrial dysfunction in patients with WS.

Decreased mitochondrial D-loop region methylation mediates an increase in mitochondrial DNA copy number in CADASIL

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a typical neurodegenerative disease associated with mitochondrial dysfunction. Methylation of the D-loop region and mitochondrial DNA copy number (mtDNAcn) play a critical role in the maintenance of mitochondrial function. However, the association between D-loop region methylation, mtDNAcn and CADASIL remains unclear.MethodsOverall, 162 individuals were recruited, including 66 CADASIL patients and 96 age- and sex-matched controls. After extracting genomic DNA from the peripheral white blood cells, levels of D-loop methylation and mtDNAcn were assessed using MethylTarget sequencing and real-time PCR, respectively.ResultsWe observed increased mtDNAcn and decreased D-loop methylation levels in CADASIL patients compared to the control group, regardless of gender stratification. Besides, we found a negative correlation between D-loop methylation levels and mtDNAcn. Mediation effect analysis shows that the proportion of the association between mtDNAcn and CADASIL that is mediated by D-loop methylation is 11.6% (95% CI 5.6, 22.6). After gender stratification, the proportions of such associations that are mediated by D-loop methylation in males and females were 7.2% (95% CI 2.4, 19.8) and 22.0% (95% CI 7.4, 50.1), respectively.ConclusionDecreased methylation of the D-loop region mediates increased mtDNAcn in CADASIL, which may be caused by a compensatory mechanism of mitochondrial dysfunction in patients with CADASIL.

Assessment of Valvular Oxidative Stress in a Young Patient with Primary Severe Mitral Regurgitation

Mitral valve regurgitation (MR) is the most common valvular heart disease. Diagnosing and managing mitral regurgitation is often challenging and requires a structured approach, integrating findings on history, physical examination and imaging. A common cardiac anomaly is myxomatous mitral valve prolapse. Excess myxomatous leaflet tissue, bileaflet prolapse or billowing, chordae elongation and annular dilatation are all features of Barlow’s disease. Currently, there is no successful pharmacological treatment available to prevent or slow its progression. Here, we report the case of a 30-year-old male patient, with no previous significant medical background and no medication at home, who was diagnosed with severe mitral regurgitation at a regular check-up and was admitted to our clinic with mild exertion dyspnea and fatigue. Transthoracic echocardiography showed intensely thickened mitral leaflets with a myxomatous appearance, prolapse of the middle scallop of the posterior leaflet (P2), apparently with ruptured chordae, and severe mitral regurgitation with a holosystolic eccentric jet. While oxidative stress is a central pathomechanism of cardiovascular disease, information regarding valvular oxidative stress in the literature is rather scarce. In this respect, we assessed oxidative stress through confocal microscopy in a sample of a mitral valve harvested during valvular surgery. We found an increased production of reactive oxygen species in the mitral valve sample that was alleviated after incubation with the angiotensin 2 receptor type I (AT1) antagonist irbesartan. This case is worth mentioning as a starting point for a prospective study aimed at assessing the role of valvular oxidative stress and mitochondrial dysfunction in patients with various degrees of primary and secondary mitral regurgitation.

ILB® Attenuates Clinical Symptoms and Serum Biomarkers of Oxidative/Nitrosative Stress and Mitochondrial Dysfunction in Patients with Amyotrophic Lateral Sclerosis.

Oxidative/nitrosative stress and mitochondrial dysfunction is a hallmark of amyotrophic lateral sclerosis (ALS), an invariably fatal progressive neurodegenerative disease. Here, as an exploratory arm of a phase II clinical trial (EudraCT Number 2017-005065-47), we used high performance liquid chromatography(HPLC) to investigate changes in the metabolic profiles of serum from ALS patients treated weekly for 4 weeks with a repeated sub-cutaneous dose of 1 mg/kg of a proprietary low molecular weight dextran sulphate, called ILB®. A significant normalization of the serum levels of several key metabolites was observed over the treatment period, including N-acetylaspartate (NAA), oxypurines, biomarkers of oxidative/nitrosative stress and antioxidants. An improved serum metabolic profile was accompanied by significant amelioration of the patients’ clinical conditions, indicating a response to ILB® treatment that appears to be mediated by improvement of tissue bioenergetics, decrease of oxidative/nitrosative stress and attenuation of (neuro)inflammatory processes.