Mitochondrial Structure and Function in the Metabolic Myopathy Accompanying Patients with Critical Limb Ischemia

Mitochondrial dysfunction has been implicated as a central mechanism in the metabolic myopathy accompanying critical limb ischemia (CLI). However, whether mitochondrial dysfunction is directly related to lower extremity ischemia and the structural and molecular mechanisms underpinning mitochondrial dysfunction in CLI patients is not understood. Here, we aimed to study whether mitochondrial dysfunction is a distinctive characteristic of CLI myopathy by assessing mitochondrial respiration in gastrocnemius muscle from 14 CLI patients (65.3 ± 7.8 y) and 15 matched control patients (CON) with a similar comorbidity risk profile and medication regimen but without peripheral ischemia (67.4 ± 7.4 y). Furthermore, we studied potential structural and molecular mechanisms of mitochondrial dysfunction by measuring total, sub-population, and fiber-type-specific mitochondrial volumetric content and cristae density with transmission electron microscopy and by assessing mitophagy and fission/fusion-related protein expression. Finally, we asked whether commonly used biomarkers of mitochondrial content are valid in patients with cardiovascular disease. CLI patients exhibited inferior mitochondrial respiration compared to CON. This respiratory deficit was not related to lower whole-muscle mitochondrial content or cristae density. However, stratification for fiber types revealed ultrastructural mitochondrial alterations in CLI patients compared to CON. CLI patients exhibited an altered expression of mitophagy-related proteins but not fission/fusion-related proteins compared to CON. Citrate synthase, cytochrome c oxidase subunit IV (COXIV), and 3-hydroxyacyl-CoA dehydrogenase (β-HAD) could not predict mitochondrial content. Mitochondrial dysfunction is a distinctive characteristic of CLI myopathy and is not related to altered organelle content or cristae density. Our results link this intrinsic mitochondrial deficit to dysregulation of the mitochondrial quality control system, which has implications for the development of therapeutic strategies.

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Elucidation of Molecular Mechanisms of Streptozotocin-Induced Oxidative Stress, Apoptosis, and Mitochondrial Dysfunction in Rin-5F Pancreatic β-Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2017/7054272 ◽

2017 ◽

Vol 2017 ◽

pp. 1-15 ◽

Cited By ~ 17

Author(s):

Arwa M. T. Al Nahdi ◽

Annie John ◽

Haider Raza

Keyword(s):

Oxidative Stress ◽

Type 1 Diabetes ◽

Mitochondrial Dysfunction ◽

Molecular Mechanisms ◽

Pancreatic Beta Cell ◽

Dependent Manner ◽

Respiratory Enzymes ◽

Altered Expression ◽

Pancreatic Cancer Cells

Streptozotocin is a pancreatic beta-cell-specific cytotoxin and is widely used to induce experimental type 1 diabetes in rodent models. The precise molecular mechanism of STZ cytotoxicity is however not clear. Studies have suggested that STZ is preferably absorbed by insulin-secreting β-cells and induces cytotoxicity by producing reactive oxygen species/reactive nitrogen species (ROS/RNS). In the present study, we have investigated the mechanism of cytotoxicity of STZ in insulin-secreting pancreatic cancer cells (Rin-5F) at different doses and time intervals. Cell viability, apoptosis, oxidative stress, and mitochondrial bioenergetics were studied. Our results showed that STZ induces alterations in glutathione homeostasis and inhibited the activities of the respiratory enzymes, resulting in inhibition of ATP synthesis. Apoptosis was observed in a dose- and time-dependent manner. Western blot analysis has also confirmed altered expression of oxidative stress markers (e.g., NOS and Nrf2), cell signaling kinases, apoptotic protein-like caspase-3, PARP, and mitochondrial specific proteins. These results suggest that STZ-induced cytotoxicity in pancreatic cells is mediated by an increase in oxidative stress, alterations in cellular metabolism, and mitochondrial dysfunction. This study may be significant in better understanding the mechanism of STZ-induced β-cell toxicity/resistance and the etiology of type 1 diabetes induction.

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Critical Limb Ischemia Induces Remodeling of Skeletal Muscle Motor Unit and Myonuclear- and Mitochondrial-Domains

10.1101/426403 ◽

2018 ◽

Author(s):

Mahir Mohiuddin ◽

Nan Hee Lee ◽

June Young Moon ◽

Woojin M. Han ◽

Shannon E. Anderson ◽

...

Keyword(s):

Skeletal Muscle ◽

Stem Cell ◽

Neuromuscular Junction ◽

Motor Neuron ◽

Critical Limb Ischemia ◽

Domain Size ◽

Limb Ischemia ◽

Severe Form ◽

Mitochondrial Content ◽

Muscle Stem Cell

AbstractCritical limb ischemia, the most severe form of peripheral artery disease, leads to extensive damage and alterations in skeletal muscle homeostasis. Although recent developments towards revascularization therapies have been introduced, there has been limited research into treatments for ischemic myopathy. To elucidate the regenerative mechanism of the muscle stem cell and its niche components in response to ischemic insults, we explored interactions between the vasculature, motor neuron, muscle fiber, and the muscle stem cell. We first investigated changes in the neuromuscular junction and motor neuron innervation following a surgical hindlimb ischemia model of critical limb ischemia in mice. Along with previous findings that support remodeling of the neuromuscular junction, we report that ischemic injury also causes significant alterations to the myofiber through a muscle stem cell-mediated increase of myonuclei number per fiber, a concomitant decrease in myonuclear domain size, and an increase in relative mitochondrial content per myonucleus. These results indicate that as a regenerative response to critical limb ischemia, myofibers exhibit myonuclear expansion to allow enhanced transcriptional support and an increase in mitochondrial content for bioenergetic need of the energy-demanding tissue regeneration.

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Circulating MicroRNA-4739 May Be a Potential Biomarker of Critical Limb Ischemia in Patients with Diabetes

BioMed Research International ◽

10.1155/2018/4232794 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Ju-yi Li ◽

Biao Cheng ◽

Xiu-fang Wang ◽

Zhong-jing Wang ◽

Hong-mei Zhang ◽

...

Keyword(s):

Risk Factors ◽

Critical Limb Ischemia ◽

Area Under The Curve ◽

Limb Ischemia ◽

Circulating Microrna ◽

Roc Curve Analysis ◽

Altered Expression ◽

Potential Biomarker ◽

Patients With Diabetes ◽

Noninvasive Biomarkers

Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease, which is common but rarely diagnosed. Noninvasive biomarkers are urgently required to assist in the diagnosis of CLI. Accumulating evidence indicates that miRNAs play an important role in the development of various diseases. In this study, microarray profiling revealed 11 miRNAs with significantly altered expression in four T2DM patients with CLI compared with that in four sex- and age-matched T2DM patients without CLI. In independent cohorts, qRT-PCR validation confirmed the increased miRNA-4739 level in patients with CLI versus patients without CLI. miRNA-4739 levels increased with FPG and HbA1c (all P < 0.05). After adjusting for the risk factors, miRNA-4739 levels were found to be associated with an increased odds ratio (OR) of T2DM with CLI (OR =12.818, 95% confidence intervals (CI) 1.148 to 143.143, P = 0.038). ROC curve analysis revealed that the area under the curve (AUC) of miR-4739+confounding risk factors was 0.94 (95% CI 0.891 to 0.998, P < 0.001), which was higher than that of confounding risk factors (AUC 0.94 vs. 0.91, 95% CI -0.122 to 0.060, P > 0.05) and of miR-4739 (AUC 0.94 vs. 0.69, 95% CI -0.399 to -0.101, P < 0.001), respectively. We conclude that elevated plasma miRNA-4739 levels are independently associated with CLI in T2DM patients. miRNA-4739 is implicated as a novel diagnostic marker and a potential therapeutic target for CLI in diabetes.

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Cell Therapy for Critical Limb Ischemia: Advantages, Limitations, and New Perspectives for Treatment of Patients with Critical Diabetic Vasculopathy

Current Diabetes Reports ◽

10.1007/s11892-021-01378-4 ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

Y. Gu ◽

A. Rampin ◽

V. V. Alvino ◽

G. Spinetti ◽

P. Madeddu

Keyword(s):

Cell Therapy ◽

Critical Limb Ischemia ◽

Molecular Mechanisms ◽

Limb Ischemia ◽

Diabetic Vasculopathy ◽

Current State ◽

Non Coding Rna ◽

Ongoing Work ◽

Patients With Diabetes ◽

The Uk

Abstract Purpose of Review To provide a highlight of the current state of cell therapy for the treatment of critical limb ischemia in patients with diabetes. Recent Findings The global incidence of diabetes is constantly growing with consequent challenges for healthcare systems worldwide. In the UK only, NHS costs attributed to diabetic complications, such as peripheral vascular disease, amputation, blindness, renal failure, and stroke, average £10 billion each year, with cost pressure being estimated to get worse. Although giant leaps forward have been registered in the scope of early diagnosis and optimal glycaemic control, an effective treatment for critical limb ischemia is still lacking. The present review aims to provide an update of the ongoing work in the field of regenerative medicine. Recent advancements but also limitations imposed by diabetes on the potential of the approach are addressed. In particular, the review focuses on the perturbation of non-coding RNA networks in progenitor cells and the possibility of using emerging knowledge on molecular mechanisms to design refined protocols for personalized therapy. Summary The field of cell therapy showed rapid progress but has limitations. Significant advances are foreseen in the upcoming years thanks to a better understanding of molecular bottlenecks associated with the metabolic disorders.

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Integrated application of multi-omics strategies provides insights into the environmental hypoxia response in Pelteobagrus vachelli muscle

10.22541/au.161272461.12356132/v1 ◽

2021 ◽

Author(s):

Jie Li ◽

Xia Liang ◽

Jiejie Xu ◽

Jiajia Zhang ◽

Kai Zhang ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Molecular Mechanisms ◽

Fish Mortality ◽

Inflammasome Activation ◽

Hypoxia Exposure ◽

Acute Response ◽

Mitochondrial Biosynthesis ◽

Pelteobagrus Vachelli ◽

Related Proteins

Abstract Increasing pressures on aquatic ecosystems due to pollutants, nutrient enrichment and global warming have severely depleted oxygen concentrations. This sudden and significant lack of oxygen has resulted in persistent increases fish mortality rates. Revealing the molecular mechanism of fish hypoxia adaptation will help researchers to find hypoxic markers for hypoxia induced by environmental stress. Here, we used a multi-omics approach to identify several hypoxia-associated miRNAs, mRNAs, proteins, and metabolites involved in diverse biological pathways in the muscles of Pelteobagrus vachelli. Our findings revealed significant hypoxia-associated changes in muscles over 4 h of hypoxia exposure and discrete tissue-specific patterns. We have previously reported that P. vachelli livers exhibit increased anaerobic glycolysis, heme synthesis, erythropoiesis, and inhibit apoptosis when exposed to hypoxia 4 h. However, the opposite was observed in muscles. According to our comprehensive analysis, fishes show an acute response to hypoxia, including activation of catabolic pathways to generate more energy, reduction of biosynthesis to decrease energy consumption, and shifting from aerobic to anaerobic metabolic contributions. Also we found that hypoxia induced muscle dysfunction by impairing mitochondrial function, activating inflammasomes, and apoptosis. The hypoxia-induced mitochondrial dysfunction enhanced oxidative stress, apoptosis, and further triggered IL-1β production via inflammasome activation. In turn, IL-1β further impaired mitochondrial function or apoptosis by suppressing downstream mitochondrial biosynthesis-related proteins, thus resulting in a vicious cycle of inflammasome activation and mitochondrial dysfunction. Our findings contribute meaningful insights into the molecular mechanisms of hypoxia, and the methods and study design can be utilized across different fish species.

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