Mitochondria and Aging-The Role of Exercise as a Countermeasure

Mitochondrial dysfunction and its association with age-related disorders

Aging is a complex process that features a functional decline in many organelles. Various factors influence the aging process, such as chromosomal abnormalities, epigenetic changes, telomere shortening, oxidative stress, and mitochondrial dysfunction. Mitochondrial dysfunction significantly impacts aging because mitochondria regulate cellular energy, oxidative balance, and calcium levels. Mitochondrial integrity is maintained by mitophagy, which helps maintain cellular homeostasis, prevents ROS production, and protects against mtDNA damage. However, increased calcium uptake and oxidative stress can disrupt mitochondrial membrane potential and permeability, leading to the apoptotic cascade. This disruption causes increased production of free radicals, leading to oxidative modification and accumulation of mitochondrial DNA mutations, which contribute to cellular dysfunction and aging. Mitochondrial dysfunction, resulting from structural and functional changes, is linked to age-related degenerative diseases. This review focuses on mitochondrial dysfunction, its implications in aging and age-related disorders, and potential anti-aging strategies through targeting mitochondrial dysfunction.

Aging and "Age-Related" Diseases - What Is the Relation?

The study explores the intricate relationship between aging and the development of noncommunicable diseases [NCDs], focusing on whether these diseases are inevitable consequences of aging or primarily driven by lifestyle factors. By examining epidemiological data, particularly from hunter-gatherer societies, the study highlights that many NCDs prevalent in modern populations are rare in these societies, suggesting a significant influence of lifestyle choices. It delves into the mechanisms through which poor diet, smoking, and other lifestyle factors contribute to systemic physiological imbalances, characterized by oxidative stress, insulin resistance and hyperinsulinemia, and dysregulation of the sympathetic nervous system, the renin-angiotensin-aldosterone system, and the immune system. The interplay between this pattern and individual factors such as genetic susceptibility, biological variability, epigenetic changes and the microbiome is proposed to play a crucial role in the development of a range of age-related NCDs. Modified biomolecules such as oxysterols and advanced glycation end products also contribute to their development. Specific diseases such as benign prostatic hyperplasia, Parkinson's disease, glaucoma and osteoarthritis are analyzed to illustrate these mechanisms. The study concludes that while aging contributes to the risk of NCDs, lifestyle factors play a crucial role, offering potential avenues for prevention and intervention through healthier living practices. One possible approach could be to try to restore the physiological balance, e.g. through dietary measures [e.g. Mediterranean diet, Okinawan diet or Paleolithic diet] in conjunction with [a combination of] pharmacological interventions and other lifestyle changes.

Effects of voluntary and forced physical exercise on the retinal health of aging Wistar rats

Aging is accompanied by an increased prevalence of degenerative conditions, including those affecting ocular health, which significantly impact quality of life and increase the burden on healthcare systems. Among these, retinal aging is of particular concern due to its direct link to vision impairment, a leading cause of disability in the elderly. Vision loss in the aging population is associated with heightened risks of cognitive decline, social isolation, and morbidity. This study addresses the critical gap in our understanding of modifiable lifestyle factors, such as physical exercise, that may mitigate retinal aging and its related pathologies. We investigated the effects of different exercise regimens-voluntary (recreational-type) and forced (high-intensity)-on the retinal health of aging Wistar rats (18-month-old), serving as a model for studying the translational potential of exercise interventions in humans. Male Wistar rats were divided into four groups: a young control (3-month-old) for baseline comparison, an aged sedentary control, an aged group engaging in voluntary exercise via a running wheel in their cage, and an aged group subjected to forced exercise on a treadmill for six sessions of 20 min each per week. After a 6-month experimental period, we assessed retinal function via electroretinography (ERG), measured retinal thickness histologically, and analyzed protein expression changes relevant to oxidative stress, inflammation, and anti-aging mechanisms. Our findings reveal that voluntary exercise positively impacts retinal function and morphology, reducing oxidative stress and inflammation markers while enhancing anti-aging protein expression. In contrast, forced exercise showed diminished benefits. These insights underscore the importance of exercise intensity and preference in preserving retinal health during aging. The study highlights the potential of recreational physical activity as a non-invasive strategy to counteract retinal aging, advocating for further research into exercise regimens as preventative therapies for age-related ocular degenerations.

Mitochondria transcription and cancer

Mitochondria are major organelles involved in several processes related to energy supply, metabolism, and cell proliferation. The mitochondria function is transcriptionally regulated by mitochondria DNA (mtDNA), which encodes the key proteins in the electron transport chain that is indispensable for oxidative phosphorylation (OXPHOS). Mitochondrial transcriptional abnormalities are closely related to a variety of human diseases, such as cardiovascular diseases, and diabetes. The mitochondria transcription is regulated by the mtDNA, mitochondrial RNA polymerase (POLRMT), two transcription factors (TFAM and TF2BM), one transcription elongation (TEFM), and one known transcription termination factor (mTERFs). Dysregulation of these factors directly leads to altered expression of mtDNA in tumor cells, resulting in cellular metabolic reprogramming and mitochondrial dysfunction. This dysregulation plays a role in modulating tumor progression. Therefore, understanding the role of mitochondrial transcription in cancer can have implications for cancer diagnosis, prognosis, and treatment. Targeting mitochondrial transcription or related pathways may provide potential therapeutic strategies for cancer treatment. Additionally, assessing mitochondrial transcriptional profiles or biomarkers in cancer cells or patient samples may offer diagnostic or prognostic information.

The antioxidant and anti-inflammatory activities of avasopasem manganese in age-associated, cisplatin-induced renal injury

PURPOSE

Cisplatin contributes to acute kidney injury (AKI) and chronic kidney disease (CKD) that occurs with greater frequency and severity in older patients. Age-associated cisplatin sensitivity in human fibroblasts involves increased mitochondrial superoxide produced by older donor cells.

EXPERIMENTAL DESIGN

Young and old C57BL/6 J murine models of cisplatin-induced AKI and CKD were treated with the SOD mimetic avasopasem manganese to investigate the potential antioxidant and anti-inflammatory effects. Adverse event reporting from a phase 2 and a phase 3 randomized clinical trial (NCT02508389 and NCT03689712) conducted in patients treated with cisplatin and AVA was determined to have established the incidence and severity of AKI.

RESULTS

Cisplatin-induced AKI and CKD occurred in all mice, however, was more pronounced in older mice. AVA reduced cisplatin-induced mortality, AKI, and CKD, in older animals. AVA also alleviated cisplatin-induced alterations in mitochondrial electron transport chain (ETC) complex activities and NADPH Oxidase 4 (NOX4) and inhibited the increased levels of the inflammation markers, TNFα, IL1, ICAM-1, and VCAM-1. Analysis of age-stratified subjects treated with cisplatin from clinical trials (NCT02508389, NCT03689712) also supported that the incidence of AKI increased with age and AVA reduced age-associated therapy-induced adverse events (AE), including hypomagnesemia, increased creatinine, and AKI.

CONCLUSIONS

Older mice and humans are more susceptible to cisplatin-induced kidney injury, and treatment with AVA mitigates age-associated damage. Mitochondrial ETC and NOX4 activities represent sources of superoxide production contributing to cisplatin-induced kidney injury, and pro-inflammatory cytokine production and endothelial dysfunction may also be increased by superoxide formation.

Mitochondrial respiration atlas reveals differential changes in mitochondrial function across sex and age

Organ function declines with age, and large-scale transcriptomic analyses have highlighted differential aging trajectories across tissues. The mechanisms underlying shared and organ-selective functional changes across the lifespan, however, still remains poorly understood. Given the central role of mitochondria in powering cellular processes needed to maintain tissue health, we therefore undertook a systematic assessment of respiratory activity across 33 different tissues in young (2.5 months) and old (20 months) mice of both sexes. Our high-resolution mitochondrial respiration atlas reveals: 1) within any group of mice, mitochondrial activity varies widely across tissues, with the highest values consistently seen in heart, brown fat, and kidney; 2) biological sex is a significant but minor contributor to mitochondrial respiration, and its contributions are tissue-specific, with major differences seen in the pancreas, stomach, and white adipose tissue; 3) age is a dominant factor affecting mitochondrial activity, especially across different fat depots and skeletal muscle groups, and most brain regions; 4) age-effects can be sex- and tissue-specific, with some of the largest effects seen in pancreas, heart, adipose tissue, and skeletal muscle; and 5) while aging alters the functional trajectories of mitochondria in a majority of tissues, some are remarkably resilient to age-induced changes. Altogether, our data provide the most comprehensive compendium of mitochondrial respiration and illuminate functional signatures of aging across diverse tissues and organ systems.

The Potential of Exercise on Lifestyle and Skin Function: Narrative Review

BACKGROUND

The skin is an important organ of the human body and has moisturizing and barrier functions. Factors such as sunlight and lifestyle significantly affect these skin functions, with sunlight being extremely damaging. The effects of lifestyle habits such as smoking, diet, and sleep have been studied extensively. It has been found that smoking increases the risk of wrinkles, while excessive fat and sugar intake leads to skin aging. Lack of sleep and stress are also dangerous for the skin's barrier function. In recent years, the impact of exercise habits on skin function has been a focus of study. Regular exercise is associated with increased blood flow to the skin, elevated skin temperature, and improved skin moisture. Furthermore, it has been shown to improve skin structure and rejuvenate its appearance, possibly through promoting mitochondrial biosynthesis and affecting hormone secretion. Further research is needed to understand the effects of different amounts and content of exercise on the skin.

OBJECTIVE

This study aims to briefly summarize the relationship between lifestyle and skin function and the mechanisms that have been elucidated so far and introduce the expected effects of exercise on skin function.

METHODS

We conducted a review of the literature using PubMed and Google Scholar repositories for relevant literature published between 2000 and 2022 with the following keywords: exercise, skin, and life habits.

RESULTS

Exercise augments the total spectrum power density of cutaneous blood perfusion by a factor of approximately 8, and vasodilation demonstrates an enhancement of approximately 1.5-fold. Regular exercise can also mitigate age-related skin changes by promoting mitochondrial biosynthesis. However, not all exercise impacts are positive; for instance, swimming in chlorinated pools may harm the skin barrier function. Hence, the exercise environment should be considered for its potential effects on the skin.

CONCLUSIONS

This review demonstrates that exercise can potentially enhance skin function retention.

Mitochondrial Dysfunction: A Key Player in Brain Aging and Diseases

Mitochondria are thought to have become incorporated within the eukaryotic cell approximately 2 billion years ago and play a role in a variety of cellular processes, such as energy production, calcium buffering and homeostasis, steroid synthesis, cell growth, and apoptosis, as well as inflammation and ROS production. Considering that mitochondria are involved in a multitude of cellular processes, mitochondrial dysfunction has been shown to play a role within several age-related diseases, including cancers, diabetes (type 2), and neurodegenerative diseases, although the underlying mechanisms are not entirely understood. The significant increase in lifespan and increased incidence of age-related diseases over recent decades has confirmed the necessity to understand the mechanisms by which mitochondrial dysfunction impacts the process of aging and age-related diseases. In this review, we will offer a brief overview of mitochondria, along with structure and function of this important organelle. We will then discuss the cause and consequence of mitochondrial dysfunction in the aging process, with a particular focus on its role in inflammation, cognitive decline, and neurodegenerative diseases, such as Huntington's disease, Parkinson's disease, and Alzheimer's disease. We will offer insight into therapies and interventions currently used to preserve or restore mitochondrial functioning during aging and neurodegeneration.

The association of skeletal muscle energetics with recurrent falls in older adults within the Study of Muscle, Mobility and Aging (SOMMA)

Background

Falls in the older population are a major public health concern. While many physiological and environmental factors have been associated with fall risk, muscle mitochondrial energetics has not yet been investigated.

Methods

In this analysis, 835 Study of Muscle, Mobility and Aging (SOMMA) participants aged 70-94 were surveyed for recurrent falls (2+) after one year. Skeletal muscle energetics were assessed at baseline in vivo using 31 P Magnetic Resonance Spectroscopy (MRS) (ATPmax) and ex vivo by High Resolution Respirometry (HRR) of permeabilized muscle fibers from the vastus lateralis (MaxOXPHOS).

Results

SOMMA participants who reported recurrent falls (12%) had a slower 400m walk gait speed compared to those with 0-1 falls (1.0 +/-0.2 vs. 1.1 +/-0.2, p<.001) and took a greater number of medication in the 30 days before their baseline visit (5.6 +/-4.4 vs. 4.2 +/-3.4, p<0.05). MaxOXPHOS was significantly lower in those who reported recurrent falls (p=0.008) compared to those with one or fewer falls, but there was no significant difference in ATPmax (p=0.369). Neither muscle energetics measure was significantly associated with total number of falls or injurious falls, but recurrent falls were significantly higher with lower MaxOXPHOS (RR=1.33, 95% CI= 1.02-1.73, p=0.033). However, covariates accounted for the increased risk.

Conclusions

Ex vivo maximal muscle mitochondrial energetics were lower in older adults who experienced recurrent falls, but covariates accounted for its association with recurrent fall risk, suggesting this "hallmark of aging" may not be directly implicated in the complex etiology of falls.

Mitochondrial dysfunction and skeletal muscle atrophy: Causes, mechanisms, and treatment strategies

Skeletal muscle, which accounts for approximately 40% of total body weight, is one of the most dynamic and plastic tissues in the human body and plays a vital role in movement, posture and force production. More than just a component of the locomotor system, skeletal muscle functions as an endocrine organ capable of producing and secreting hundreds of bioactive molecules. Therefore, maintaining healthy skeletal muscles is crucial for supporting overall body health. Various pathological conditions, such as prolonged immobilization, cachexia, aging, drug-induced toxicity, and cardiovascular diseases (CVDs), can disrupt the balance between muscle protein synthesis and degradation, leading to skeletal muscle atrophy. Mitochondrial dysfunction is a major contributing mechanism to skeletal muscle atrophy, as it plays crucial roles in various biological processes, including energy production, metabolic flexibility, maintenance of redox homeostasis, and regulation of apoptosis. In this review, we critically examine recent knowledge regarding the causes of muscle atrophy (disuse, cachexia, aging, etc.) and its contribution to CVDs. Additionally, we highlight the mitochondrial signaling pathways involvement to skeletal muscle atrophy, such as the ubiquitin-proteasome system, autophagy and mitophagy, mitochondrial fission-fusion, and mitochondrial biogenesis. Furthermore, we discuss current strategies, including exercise, mitochondria-targeted antioxidants, in vivo transfection of PGC-1α, and the potential use of mitochondrial transplantation as a possible therapeutic approach.

Mitochondrial Genome Variation in Polish Elite Athletes

Energy efficiency is one of the fundamental athletic performance-affecting features of the cell and the organism as a whole. Mitochondrial DNA (mtDNA) variants and haplogroups have been linked to the successful practice of various sports, but despite numerous studies, understanding of the correlation is far from being comprehensive. In this study, the mtDNA sequence and copy number were determined for 99 outstanding Polish male athletes performing in power (n = 52) or endurance sports (n = 47) and 100 controls. The distribution of haplogroups, single nucleotide variant association, heteroplasmy, and mtDNA copy number were analyzed in the blood and saliva. We found no correlation between any haplogroup, single nucleotide variant, especially rare or non-synonymous ones, and athletic performance. Interestingly, heteroplasmy was less frequent in the study group, especially in endurance athletes. We observed a lower mtDNA copy number in both power and endurance athletes compared to controls. This could result from an inactivity of compensatory mechanisms activated by disadvantageous variants present in the general population and indicates a favorable genetic makeup of the athletes. The results emphasize a need for a more comprehensive analysis of the involvement of the mitochondrial genome in physical performance, combining nucleotide and copy number analysis in the context of nuclear gene variants.

A balanced formula of essential amino acids promotes brain mitochondrial biogenesis and protects neurons from ischemic insult

Mitochondrial dysfunction plays a key role in the aging process, and aging is a strong risk factor for neurodegenerative diseases or brain injury characterized by impairment of mitochondrial function. Among these, ischemic stroke is one of the leading causes of death and permanent disability worldwide. Pharmacological approaches for its prevention and therapy are limited. Although non-pharmacological interventions such as physical exercise, which promotes brain mitochondrial biogenesis, have been shown to exert preventive effects against ischemic stroke, regular feasibility is complex in older people, and nutraceutical strategies could be valuable alternatives. We show here that dietary supplementation with a balanced essential amino acid mixture (BCAAem) increased mitochondrial biogenesis and the endogenous antioxidant response in the hippocampus of middle-aged mice to an extent comparable to those elicited by treadmill exercise training, suggesting BCAAem as an effective exercise mimetic on brain mitochondrial health and disease prevention. In vitro BCAAem treatment directly exerted mitochondrial biogenic effects and induced antioxidant enzyme expression in primary mouse cortical neurons. Further, exposure to BCAAem protected cortical neurons from the ischemic damage induced by an in vitro model of cerebral ischemia (oxygen-glucose deprivation, OGD). BCAAem-mediated protection against OGD was abolished in the presence of rapamycin, Torin-1, or L-NAME, indicating the requirement of both mTOR and eNOS signaling pathways in the BCAAem effects. We propose BCAAem supplementation as an alternative to physical exercise to prevent brain mitochondrial derangements leading to neurodegeneration and as a nutraceutical intervention aiding recovery after cerebral ischemia in conjunction with conventional drugs.

Resistance training prevents dynamics and mitochondrial respiratory dysfunction in vastus lateralis muscle of ovariectomized rats

To investigate whether ovariectomy affects mitochondrial respiratory function, gene expression of the biogenesis markers and mitochondrial dynamics of the vastus lateralis muscle, female Wistar rats divided into ovariectomized (OVX) and intact (INT) groups were kept sedentary (SED) or submitted to resistance training (RT) performed for thirteen weeks on a vertical ladder in which animals climbed with a workload apparatus. RT sessions were performed with four climbs with 65, 85, 95, and 100 % of the rat's previous maximum workload. Mitochondrial Respiratory Function data were obtained by High-resolution respirometry. Gene expression of FIS1, MFN1 and PGC1-α was evaluated by real-time PCR. There was a decrease on oxidative phosphorylation capacity in OVX-SED compared to other groups. Trained groups presented increase on oxidative phosphorylation capacity when compared to sedentary groups. For respiratory control ratio (RCR), OVX-SED presented lower values when compared to INT-SED and to trained groups. Trained groups presented RCR values higher compared to INT-SED. Exercise increased the values of FIS1, MFN1 and PGC1-α expression compared to OVX-SED. Our results demonstrated that in the absence of ovarian hormones, there is a great decrease in oxidative phosphorylation and electron transfer system capacities of sedentary animals. RT was able to increase the expression of genes related to mitochondrial dynamics markers, reversing the condition determined by ovariectomy.

ATPase Inhibitory Factor 1-A Novel Marker of Cellular Fitness and Exercise Capacity?

ATPase inhibitory factor 1 is a myokine inhibiting the hydrolytic activity of mitochondrial adenosine triphosphate synthase and ecto-F1-ATPase on the surface of many cells. IF1 affects ATP metabolism in mitochondria and the extracellular space and upregulates glucose uptake in myocytes; these processes are essential in physical activity. It is unknown whether the IF1 serum concentration is associated with exercise capacity. This study explored the association between resting IF1 serum concentration and exercise capacity indices in healthy people. IF1 serum concentration was measured in samples collected at rest in 97 healthy amateur cyclists. Exercise capacity was assessed on a bike ergometer at the successive stages of the progressive cardiopulmonary exercise test (CPET). IF1 serum concentration was negatively and significantly correlated with oxygen consumption, oxygen pulse, and load at various CPET stages. A better exercise capacity was associated with lower circulating IF1. IF1 may reflect better cellular/mitochondrial energetic fitness, but there is uncertainty regarding how IF1 is released into the intravascular space. We speculate that lower IF1 concentration may reflect a better cellular/mitochondrial integrity, as this protein is bound more strongly with ATPases in mitochondria and cellular surfaces in people with higher exercise capacity.

Developing and pilot testing a frailty-focused education and communication training workshop

Objective

To describe development and pilot testing of a multi-modal frailty-focused education and communication training workshop for health care clinicians.

Methods

Pilot testing was conducted via two workshops (#1:face-to-face [2019], #2:virtual [2020]). Participants: convenience sample of clinicians and students who volunteered. Workshop #1 included registered nurses working in an acute care and one medical student (N=14); #2: nursing students enrolled in an APRN program. Design: Pre/post observational study. Data analysis: descriptive statistics, paired t-tests and Wilcoxon rank test.

Results

Statistically significant increases in frailty knowledge (#1: p = 0.02, d = 0.44; #2: p = 0.006, d = 0.55) and self-reported competency with older adult interactions (#1: p < 0.001, d = 0.62; #2: p = 0.001, d = 0.63) were reported for both workshops. Post course evaluations of the workshop were positive, with scores ranging from 3.5-3.9 (range: 0-4) for increased understanding of the concept of frailty, communication to support health-related behavior, and best practice empathic communication skills.

Conclusion

The FCOM workshop was successful. Participants gained knowledge and skills for use in working with older adults across the aging continuum from non-frail to frail.

Innovation

Our FCOM training workshop expands prior communication training on shared decision-making with frail individuals to a broader population of all older adults.

Scientific meeting report: International Biochemistry of Exercise 2022

Exercise is one of the only nonpharmacological remedies known to counteract genetic and chronic diseases by enhancing health and improving life span. Although the many benefits of regular physical activity have been recognized for some time, the intricate and complex signaling systems triggered at the onset of exercise have only recently begun to be uncovered. Exercising muscles initiate a coordinated, multisystemic, metabolic rewiring, which is communicated to distant organs by various molecular mediators. The field of exercise research has been expanding beyond the musculoskeletal system, with interest from industry to provide realistic models and exercise mimetics that evoke a whole body rejuvenation response. The 18th International Biochemistry of Exercise conference took place in Toronto, Canada, from May 25 to May 28, 2022, with more than 400 attendees. Here, we provide an overview of the most cutting-edge exercise-related research presented by 66 speakers, focusing on new developments in topics ranging from molecular and cellular mechanisms of exercise adaptations to exercise therapy and management of disease and aging. We also describe how the manipulation of these signaling pathways can uncover therapeutic avenues for improving human health and quality of life.

Redox-based disruption of cellular hormesis and promotion of degenerative pathways: perspectives on ageing processes

The present work aims to link the redox and cell-centric theories of chronic processes in human biology, focusing on ageing. A synthetic overview of cellular redox pathways will be integrated by the concept of hormesis, which disruption leads to several physiopathological processes. The onset of age-related diseases due to the restriction of homeodynamic capacity will be herein considered in a redox fashion. Up-to-date arguments on hormetic agents, such as geroprotectors, dietary interventions, and physical exercise are refining the presented theoretical framework, integrated by insights from extracellular vesicles, microbiota, pollutants, and timing mechanisms. The broad concepts of exposome encompass the redox-based alteration of cellular hormesis for providing meaningful perspectives on redox biogerontology.

Impact of Exercise and Aging on Mitochondrial Homeostasis in Skeletal Muscle: Roles of ROS and Epigenetics

Aging causes degenerative changes such as epigenetic changes and mitochondrial dysfunction in skeletal muscle. Exercise can upregulate muscle mitochondrial homeostasis and enhance antioxidant capacity and represents an effective treatment to prevent muscle aging. Epigenetic changes such as DNA methylation, histone posttranslational modifications, and microRNA expression are involved in the regulation of exercise-induced adaptive changes in muscle mitochondria. Reactive oxygen species (ROS) play an important role in signaling molecules in exercise-induced muscle mitochondrial health benefits, and strong evidence emphasizes that exercise-induced ROS can regulate gene expression via epigenetic mechanisms. The majority of mitochondrial proteins are imported into mitochondria from the cytosol, so mitochondrial homeostasis is regulated by nuclear epigenetic mechanisms. Exercise can reverse aging-induced changes in myokine expression by modulating epigenetic mechanisms. In this review, we provide an overview of the role of exercise-generated ROS in the regulation of mitochondrial homeostasis mediated by epigenetic mechanisms. In addition, the potential epigenetic mechanisms involved in exercise-induced myokine expression are reviewed.

The Role of Systemic Filtrating Organs in Aging and Their Potential in Rejuvenation Strategies

Advances in aging studies brought about by heterochronic parabiosis suggest that aging might be a reversable process that is affected by changes in the systemic milieu of organs and cells. Given the broadness of such a systemic approach, research to date has mainly questioned the involvement of “shared organs” versus “circulating factors”. However, in the absence of a clear understanding of the chronological development of aging and a unified platform to evaluate the successes claimed by specific rejuvenation methods, current literature on this topic remains scattered. Herein, aging is assessed from an engineering standpoint to isolate possible aging potentiators via a juxtaposition between biological and mechanical systems. Such a simplification provides a general framework for future research in the field and examines the involvement of various factors in aging. Based on this simplified overview, the kidney as a filtration organ is clearly implicated, for the first time, with the aging phenomenon, necessitating a re-evaluation of current rejuvenation studies to untangle the extent of its involvement and its possible role as a potentiator in aging. Based on these findings, the review concludes with potential translatable and long-term therapeutics for aging while offering a critical view of rejuvenation methods proposed to date.

Unbiased proteomics, histochemistry, and mitochondrial DNA copy number reveal better mitochondrial health in muscle of high functioning octogenarians

Background: Master athletes prove that preserving a high level of physical function up to very late in life is possible, but the mechanisms responsible for their high function remain unclear.

Methods: We performed muscle biopsies in 15 octogenarian world class track and field masters athletes (MA) and 14 non-athlete age/sex-matched controls (NA) to provide insights into mechanisms for preserving function in advanced age. Muscle samples were assessed for respiratory compromised fibers, mtDNA copy number, and proteomics by liquid-chromatography mass spectrometry.

Results: MA exhibited markedly better performance on clinical function tests and greater cross-sectional area of the vastus lateralis muscle. Proteomics analysis revealed marked differences, where most of the ~800 differentially represented proteins in MA versus NA pertained to mitochondria structure/function such as electron transport capacity (ETC), cristae formation, mitochondrial biogenesis, and mtDNA-encoded proteins. In contrast, proteins from the spliceosome complex and nuclear pore were downregulated in MA. Consistent with proteomics data, MA had fewer respiratory compromised fibers, higher mtDNA copy number, and an increased protein ratio of the cristae-bound ETC subunits relative to the outer mitochondrial membrane protein voltage dependent anion channel. There was a substantial overlap of proteins overrepresented in MA versus NA with proteins that decline with aging and which are higher in physically active than sedentary individuals. However, we also found 176 proteins related to mitochondria that are uniquely differentially expressed in MA.

Conclusions: We conclude that high function in advanced age is associated with preserving mitochondrial structure/function proteins, with under-representation of proteins involved in the spliceosome and nuclear pore complex. Whereas many of these differences in MA appear related to their physical activity habits, others may reflect unique biological (e.g., gene, environment) mechanisms that preserve muscle integrity and function with aging.

Funding: Funding for this study was provided by operating grants from the Canadian Institutes of Health Research (MOP 84408 to TT and MOP 125986 to RTH). Supported in part by the Intramural Research Program of the National Institute on Aging, NIH, Baltimore, MD, United States.

Circulating Mitochondrial DNA and Inter-Organelle Contact Sites in Aging and Associated Conditions

Mitochondria are primarily involved in cell bioenergetics, regulation of redox homeostasis, and cell death/survival signaling. An immunostimulatory property of mitochondria has also been recognized which is deployed through the extracellular release of entire or portioned organelle and/or mitochondrial DNA (mtDNA) unloading. Dynamic homo- and heterotypic interactions involving mitochondria have been described. Each type of connection has functional implications that eventually optimize mitochondrial activity according to the bioenergetic demands of a specific cell/tissue. Inter-organelle communications may also serve as molecular platforms for the extracellular release of mitochondrial components and subsequent ignition of systemic inflammation. Age-related chronic inflammation (inflamm-aging) has been associated with mitochondrial dysfunction and increased extracellular release of mitochondrial components—in particular, cell-free mtDNA. The close relationship between mitochondrial dysfunction and cellular senescence further supports the central role of mitochondria in the aging process and its related conditions. Here, we provide an overview of (1) the mitochondrial genetic system and the potential routes for generating and releasing mtDNA intermediates; (2) the pro-inflammatory pathways elicited by circulating mtDNA; (3) the participation of inter-organelle contacts to mtDNA homeostasis; and (4) the link of these processes with senescence and age-associated conditions.

Levels of Plasma Coenzyme Q10 Are Associated with Physical Capacity and Cardiovascular Risk in the Elderly

Coenzyme Q₁₀ (CoQ₁₀) is an essential factor for mitochondrial activity and antioxidant protection of cells, tissues and plasma lipoproteins. Its deficiency has been associated with aging progression in animals and humans. To determine if CoQ₁₀ levels in plasma can be associated with frailty in elderly people (aged > 65), we studied the relationship of CoQ₁₀ levels in blood with other parameters in plasma and with the physical activity and capacity in aged people. Our results indicate that high CoQ₁₀ levels are directly associated with lower cardiovascular risk measured by the quotient total cholesterol/HDL cholesterol. Furthermore, high CoQ₁₀ levels were found in people showing higher physical activity, stronger muscle capacity. CoQ₁₀ also showed a strong inverse relationship with sedentarism and the up and go test, which is considered to be a frailty index. Interestingly, we found gender differences, indicating stronger correlations in women than in men. The importance of the maintenance of CoQ₁₀ levels in elderly people to avoid sarcopenia and frailty in elderly people is discussed.

Impact of exercise training on muscle mitochondria modifications in older adults: a systematic review of randomized controlled trials

BACKGROUND

Previous evidence showed that cellular aging is a multifactorial process that is associated with decline in mitochondrial function. Physical exercise has been proposed as an effective and safe therapeutical intervention to improve the mitochondria network in the adult myocytes.

AIMS

The aim of this systematic review of randomized controlled trials (RCTs) was to assess the exercise-induced muscle mitochondria modifications in older adults, underlining the differences related to different exercise modalities.

METHODS

On November 28th, 2021, five databases (PubMed, Scopus, Web of Science, Cochrane, and PEDro) were systematically searched for RCTs to include articles with: healthy older people as participants; physical exercise (endurance training (ET), resistance training (RT), and combined training (CT)) as intervention; other different exercise modalities or physical inactivity as comparator; mitochondrial modifications (quality, density and dynamics, oxidative, and antioxidant capacity) as outcomes. The quality assessment was performed according to the PEDro scale; the bias risk was evaluated by Cochrane risk-of-bias assessment tool.

RESULTS

Out of 2940 records, 6 studies were included (2 assessing ET, 2 RT, 1 CT, and 1 both ET and RT). Taken together, 164 elderly subjects were included in the present systematic review. Significant positive effects were reported in terms of mitochondrial quality, density, dynamics, oxidative and antioxidant capacity, even though with different degrees according to the exercise type. The quality assessment reported one good-quality study, whereas the other five studies had a fair quality.

DISCUSSION

The overall low quality of the studies on this topic indicate that further research is needed.

CONCLUSION

RT seems to be the most studied physical exercise modality improving mitochondrial density and dynamics, while ET have been related to mitochondrial antioxidant capacity improvements. However, these exercise-induced specific effects should be better explored in older people.

Lipid Droplets Protect Aging Mitochondria and Thus Promote Lifespan in Yeast Cells

Besides their role as a storage for neutral lipids and sterols, there is increasing evidence that lipid droplets (LDs) are involved in cellular detoxification. LDs are in close contact to a broad variety of organelles where protein- and lipid exchange is mediated. Mitochondria as a main driver of the aging process produce reactive oxygen species (ROS), which damage several cellular components. LDs as highly dynamic organelles mediate a potent detoxification mechanism by taking up toxic lipids and proteins. A stimulation of LDs induced by the simultaneously overexpression of Lro1p and Dga1p (both encoding acyltransferases) prolongs the chronological as well as the replicative lifespan of yeast cells. The increased number of LDs reduces mitochondrial fragmentation as well as mitochondrial ROS production, both phenotypes that are signs of aging. Strains with an altered LD content or morphology as in the sei1∆ or lro1∆ mutant lead to a reduced replicative lifespan. In a yeast strain defective for the LON protease Pim1p, which showed an enhanced ROS production, increased doubling time and an altered mitochondrial morphology, a LRO1 overexpression resulted in a partially reversion of this "premature aging" phenotype.

How can we minimize the risks by optimizing patient's condition shortly before thoracic surgery?

The “moderate-to-high-risk” surgical patient is typically older, frail, malnourished, suffering from multiple comorbidities and presenting with unhealthy life style such as smoking, hazardous drinking and sedentarity. Poor aerobic fitness, sarcopenia and “toxic” behaviors are modifiable risk factors for major postoperative complications. The physiological challenge of lung cancer surgery has been likened to running a marathon. Therefore, preoperative patient optimization or “ prehabilitation “ should become a key component of improved recovery pathways to enhance general health and physiological reserve prior to surgery. During the short preoperative period, the patients are more receptive and motivated to adhere to behavioral interventions (e.g., smoking cessation, weaning from alcohol, balanced food intake and active mobilization) and to follow a structured exercise training program. Sufficient protein intake should be ensured (1.5–2 g/kg/day) and nutritional defects should be corrected to restore muscle mass and strength. Currently, there is strong evidence supporting the effectiveness of various modalities of physical training (endurance training and/or respiratory muscle training) to enhance aerobic fitness and to mitigate the risk of pulmonary complications while reducing the hospital length of stay. Multimodal interventions should be individualized to the patient's condition. These bundle of care are more effective than single or sequential intervention owing to synergistic benefits of education, nutritional support and physical training. An effective prehabilitation program is necessarily patient-centred and coordinated among health care professionals (nurses, primary care physician, physiotherapists, nutritionists) to help the patient regain some control over the disease process and improve the physiological reserve to sustain surgical stress.

Role of Melatonin in Angiotensin and Aging

The cellular utilization of oxygen leads to the generation of free radicals in organisms. The accumulation of these free radicals contributes significantly to aging and several age-related diseases. Angiotensin II can contribute to DNA damage through oxidative stress by activating the NAD(P)H oxidase pathway, which in turn results in the production of reactive oxygen species. This radical oxygen-containing molecule has been linked to aging and several age-related disorders, including renal damage. Considering the role of angiotensin in aging, melatonin might relieve angiotensin-II-induced stress by enhancing the mitochondrial calcium uptake 1 pathway, which is crucial in preventing the mitochondrial calcium overload that may trigger increased production of reactive oxygen species and oxidative stress. This review highlights the role and importance of melatonin together with angiotensin in aging and age-related diseases.

Football and team handball training postpone cellular aging in women

Several hallmarks of aging have been identified and examined separately in previous exercise studies. For the first time, this study investigates the effect of lifelong regular exercise in humans on two of the central aging hallmarks combined. This cross-sectional study involved 129 healthy, non-smoking women, including young elite football players (YF, n = 29), young untrained controls (YC, n = 30), elderly team handball players (EH, n = 35) and elderly untrained controls (EC, n = 35). From a resting blood sample, mononuclear cells (MNCs) were isolated and sorted into monocytes and lymphocytes. Telomere length, mitochondrial (mtDNA) copy number and key regulators of mitochondrial biogenesis and function (PGC-1α and PGC-1β expression) were measured using quantitative polymerase chain reaction (qPCR). Overall, young women showed significantly longer telomeres and higher PGC-1α and PGC-1β expression, but lower mtDNA copy number compared to elderly subjects. A multivariate analysis showed that YF had 22–24% longer telomeres in lymphocytes and MNCs compared to YC. In addition, YF showed 19–20% higher mtDNA copy number in lymphocytes and MNCs compared to YC. The two young groups did not differ in PGC-1α and PGC-1β expression. EH showed 14% lower mtDNA copy number in lymphocytes compared to EC, but 3.4-fold higher lymphocyte PGC-1α expression compared to EC. In MNCs, EH also showed 1.4–1.6-fold higher PGC-1α and PGC-1β expression. The two elderly groups did not differ in telomere length. Elite football training and lifelong team handball training are associated with anti-aging mechanisms in leukocytes in women, including maintenance of telomere length and superior mitochondrial characteristics.

Extensive Simulated Diving Aggravates Endothelial Dysfunction in Male Pro-atherosclerotic ApoE Knockout Rats

Introduction

The average age of the diving population is rising, and the risk of atherosclerosis and cardiovascular disease in divers are accordingly increasing. It is an open question whether this risk is altered by diving per se. In this study, we examined the effect of 7-weeks simulated diving on endothelial function and mitochondrial respiration in atherosclerosis-prone rats.

Methods

Twenty-four male ApoE knockout (KO) rats (9-weeks-old) were fed a Western diet for 8 weeks before 12 rats were exposed to simulated heliox dry-diving in a pressure chamber (600 kPa for 60 min, decompression of 50 kPa/min). The rats were dived twice-weekly for 7 weeks, resulting in a total of 14 dives. The remaining 12 non-diving rats served as controls. Endothelial function of the pulmonary and mesenteric arteries was examined in vitro using an isometric myograph. Mitochondrial respiration in cardiac muscle tissues was measured using high-resolution respirometry.

Results and Conclusion

Both ApoE KO diving and non-diving rats showed changes in endothelial function at the end of the intervention, but the extent of these changes was larger in the diving group. Altered nitric oxide signaling was primarily involved in these changes. Mitochondrial respiration was unaltered. In this pro-atherosclerotic rat model of cardiovascular changes, extensive diving appeared to aggravate endothelial dysfunction rather than promote adaptation to oxidative stress.

Effects of Two-Week Betaine Supplementation on Apoptosis, Oxidative Stress, and Aerobic Capacity after Exhaustive Endurance Exercise

This study evaluated the effects of 2 weeks of betaine supplementation on apoptosis, oxidative stress, and aerobic capacity after exhaustive endurance exercise (EEE). A double-blind, crossover, and counterbalanced design was adopted, with 10 healthy male participants asked to consume betaine (1.25 g of betaine mixed with 300 mL of sports beverage, twice per day for 2 weeks) or placebo (300 mL of sports beverage). All participants performed a graded exercise test on a treadmill to determine the maximal oxygen consumption (VO2max) before supplementation and then performed the EEE test at an intensity of 80% VO2max after 2 weeks of supplementation. The time to exhaustion, peak oxygen consumption, maximal heart rate, and average heart rate were recorded during the EEE test. Venous blood samples were drawn before, immediately after, and 3 h after the EEE test to assess apoptosis and the mitochondrial transmembrane potential (MTP) decline of lymphocytes as well as the concentrations of thiobarbituric acid reactive substance and protein carbonyl. The results indicated that lymphocyte apoptosis was significantly higher immediately after and 3 h after EEE than before exercise in participants in the placebo trial. However, lymphocyte apoptosis exhibited no significant differences among the three time points in participants in the betaine trial. Moreover, apoptosis in the betaine trial was significantly lower immediately after and 3 h after exercise compared with the placebo trial. No differences were noted for other variables. Thus, 2 weeks of betaine supplementation can effectively attenuate lymphocyte apoptosis, which is elevated by EEE. However, betaine supplementation exhibited no effects on MTP decline, oxidative stress, or aerobic capacity.

Effects of exercise training on the biochemical pathways associated with sarcopenia

[Purpose]

Sarcopenia is considered one of the major causes of disability in the elderly population and is highly associated with aging. Exercise is an essential strategy for improving muscle health while aging and involves multiple metabolic and transcriptional adaptations. Although the beneficial effects of exercise modalities on skeletal muscle structure and function in aging are well recognized, the exact cellular and molecular mechanisms underlying the influence of exercise have not been fully elucidated.

[Methods]

We summarize the biochemical pathways involved in the progression and pathogenesis of sarcopenia and describe the beneficial effects of exercise training on the relevant signaling pathways associated with sarcopenia.

[Results]

This study briefly introduces current knowledge on the signaling pathways involved in the development of sarcopenia, effects of aerobic exercise on mitochondria-related parameters and mitochondrial function, and role of resistance exercise in the regulation of muscle protein synthesis against sarcopenia.

[Conclusion]

This review suggested that the beneficial effects of exercise are still under-explored, and accelerated research will help develop better modalities for the prevention, management, and treatment of sarcopenia.

Protein phase separation: A novel therapy for cancer?

In recent years, phase separation has been increasingly reported to play a pivotal role in a wide range of biological processes. Due to the close relationships between cancer and disorders in intracellular physiological function, the identification of new mechanisms involved in intracellular regulation has been regarded as a new direction for cancer therapy. Introducing the concept of phase separation into complex descriptions of disease mechanisms may provide many different insights. Here, we review the recent findings on the phase separation of cancer-related proteins, describing the possible relationships between phase separation and key proteins associated with cancer and indicate possible regulatory modalities, especially drug candidates for phase separation, which may provide more effective strategies for cancer therapy.

Aging-Related Disorders and Mitochondrial Dysfunction: A Critical Review for Prospect Mitoprotective Strategies Based on Mitochondrial Nutrient Mixtures

A number of aging-related disorders (ARD) have been related to oxidative stress (OS) and mitochondrial dysfunction (MDF) in a well-established body of literature. Most studies focused on cardiovascular disorders (CVD), type 2 diabetes (T2D), and neurodegenerative disorders. Counteracting OS and MDF has been envisaged to improve the clinical management of ARD, and major roles have been assigned to three mitochondrial cofactors, also termed mitochondrial nutrients (MNs), i.e., α-lipoic acid (ALA), Coenzyme Q10 (CoQ10), and carnitine (CARN). These cofactors exert essential–and distinct—roles in mitochondrial machineries, along with strong antioxidant properties. Clinical trials have mostly relied on the use of only one MN to ARD-affected patients as, e.g., in the case of CoQ10 in CVD, or of ALA in T2D, possibly with the addition of other antioxidants. Only a few clinical and pre-clinical studies reported on the administration of two MNs, with beneficial outcomes, while no available studies reported on the combined administration of three MNs. Based on the literature also from pre-clinical studies, the present review is to recommend the design of clinical trials based on combinations of the three MNs.

Aging Promotes Mitochondria-Mediated Apoptosis in Rat Hearts

Aging represents a major risk for developing cardiac disease, including heart failure. The gradual deterioration of cell quality control with aging leads to cell death, a phenomenon associated with mitochondrial dysfunction in the heart. Apoptosis is an important quality control process and a necessary phenomenon for maintaining homeostasis and normal function of the heart. However, the mechanism of mitochondria-mediated apoptosis in aged hearts remains poorly understood. Here, we used male Fischer 344 rats of various ages, representing very young (1 month), young (4 months), middle-aged (12 months), and old (20 months) rats, to determine whether mitochondria-mediated apoptotic signals and apoptosis in the left ventricle of the heart are altered notably with aging. As the rats aged, the extramyocyte space and myocyte cross-sectional area in their left ventricle muscle increased, while the number of myocytes decreased. Additionally, mitochondrion-mediated apoptotic signals and apoptosis increased remarkably during aging. Therefore, our results demonstrate that aging promotes remarkable morphological changes and increases the degree of mitochondrion-mediated apoptosis in the left ventricle of rat hearts.

A Five-Ingredient Nutritional Supplement and Home-Based Resistance Exercise Improve Lean Mass and Strength in Free-Living Elderly

Old age is associated with lower physical activity levels, suboptimal protein intake, and desensitization to anabolic stimuli, predisposing for age-related muscle loss (sarcopenia). Although resistance exercise (RE) and protein supplementation partially protect against sarcopenia under controlled conditions, the efficacy of home-based, unsupervised RE (HBRE) and multi-ingredient supplementation (MIS) is largely unknown. In this randomized, placebo-controlled and double-blind trial, we examined the effects of HBRE/MIS on muscle mass, strength, and function in free-living, older men. Thirty-two sedentary men underwent twelve weeks of home-based resistance band training (3 d/week), in combination with daily intake of a novel five-nutrient supplement (‘Muscle5’; M5, n = 16, 77.4 ± 2.8 y) containing whey, micellar casein, creatine, vitamin D, and omega-3 fatty acids, or an isocaloric/isonitrogenous placebo (PLA; n = 16, 74.4 ± 1.3 y), containing collagen and sunflower oil. Appendicular and total lean mass (ASM; +3%, TLM; +2%), lean mass to fat ratios (ASM/% body fat; +6%, TLM/% body fat; +5%), maximal strength (grip; +8%, leg press; +17%), and function (5-Times Sit-to-Stand time; −9%) were significantly improved in the M5 group following HBRE/MIS therapy (pre vs. post tests; p < 0.05). Fast-twitch muscle fiber cross-sectional areas of the quadriceps muscle were also significantly increased in the M5 group post intervention (Type IIa; +30.9%, Type IIx, +28.5%, p < 0.05). Sub-group analysis indicated even greater gains in total lean mass in sarcopenic individuals following HBRE/MIS therapy (TLM; +1.65 kg/+3.4%, p < 0.05). We conclude that the Muscle5 supplement is a safe, well-tolerated, and effective complement to low-intensity, home-based resistance exercise and improves lean mass, strength, and overall muscle quality in old age.

Targeting Multiple Mitochondrial Processes by a Metabolic Modulator Prevents Sarcopenia and Cognitive Decline in SAMP8 Mice

The age-dependent declines of skeletal muscle and cognitive functions often coexist in elderly subjects. The underlying pathophysiological mechanisms share common features of mitochondrial dysfunction, which plays a central role in the development of overt sarcopenia and/or dementia. Dietary supplementation with formulations of essential and branched-chain amino acids (EAA-BCAA) is a promising preventive strategy because it can preserve mitochondrial biogenesis and function. The senescence-accelerated mouse prone 8 (SAMP8) is considered an accurate model of age-related muscular and cognitive alterations. Hence, we aimed to investigate the progression of mitochondrial dysfunctions during muscular and cognitive aging of SAMP8 mice and to study the effects of a novel EAA-BCAA-based metabolic modulator on these changes. We evaluated body condition, motor endurance, and working memory of SAMP8 mice at 5, 9, 12, and 15 months of age. Parallel changes in protein levels of mitochondrial respiratory chain subunits, regulators of mitochondrial biogenesis and dynamics, and the antioxidant response, as well as respiratory complex activities, were measured in the quadriceps femoris and the hippocampus. The same variables were assessed in 12-month-old SAMP8 mice that had received dietary supplementation with the novel EAA-BCAA formulation, containing tricarboxylic acid cycle intermediates and co-factors (PD-0E7, 1.5 mg/kg/body weight/day in drinking water) for 3 months. Contrary to untreated mice, which had a significant molecular and phenotypic impairment, PD-0E7-treated mice showed preserved healthy body condition, muscle weight to body weight ratio, motor endurance, and working memory at 12 months of age. The PD-0E7 mixture increased the protein levels and the enzymatic activities of mitochondrial complex I, II, and IV and the expression of proliferator-activated receptor γ coactivator-1α, optic atrophy protein 1, and nuclear factor, erythroid 2 like 2 in muscles and hippocampi. The mitochondrial amyloid-β-degrading pitrilysin metallopeptidase 1 was upregulated, while amyloid precursor protein was reduced in the hippocampi of PD-0E7 treated mice. In conclusion, we show that a dietary supplement tailored to boost mitochondrial respiration preserves skeletal muscle and hippocampal mitochondrial quality control and health. When administered at the early onset of age-related physical and cognitive decline, this novel metabolic inducer counteracts the deleterious effects of precocious aging in both domains.

Nutritional Supplements to Support Resistance Exercise in Countering the Sarcopenia of Aging

Skeletal muscle plays an indispensable role in metabolic health and physical function. A decrease in muscle mass and function with advancing age exacerbates the likelihood of mobility impairments, disease development, and early mortality. Therefore, the development of non-pharmacological interventions to counteract sarcopenia warrant significant attention. Currently, resistance training provides the most effective, low cost means by which to prevent sarcopenia progression and improve multiple aspects of overall health. Importantly, the impact of resistance training on skeletal muscle mass may be augmented by specific dietary components (i.e., protein), feeding strategies (i.e., timing, per-meal doses of specific macronutrients) and nutritional supplements (e.g., creatine, vitamin-D, omega-3 polyunsaturated fatty acids etc.). The purpose of this review is to provide an up-to-date, evidence-based account of nutritional strategies to enhance resistance training-induced adaptations in an attempt to combat age-related muscle mass loss. In addition, we provide insight on how to incorporate the aforementioned nutritional strategies that may support the growth or maintenance of skeletal muscle and subsequently extend the healthspan of older individuals.

Macrophage Immunometabolism and Inflammaging: Roles of Mitochondrial Dysfunction, Cellular Senescence, CD38, and NAD

Aging is a complex process that involves dysfunction on multiple levels, all of which seem to converge on inflammation. Macrophages are intimately involved in initiating and resolving inflammation, and their dysregulation with age is a primary contributor to inflammaging—a state of chronic, low-grade inflammation that develops during aging. Among the age-related changes that occur to macrophages are a heightened state of basal inflammation and diminished or hyperactive inflammatory responses, which seem to be driven by metabolic-dependent epigenetic changes. In this review article we provide a brief overview of mitochondrial functions and age-related changes that occur to macrophages, with an emphasis on how the inflammaging environment, senescence, and NAD decline can affect their metabolism, promote dysregulation, and contribute to inflammaging and age-related pathologies.

Increased intra-mitochondrial lipofuscin aggregates with spherical dense body formation in mitochondrial myopathy

Lipofuscin aggregation may result from incomplete degradation of damaged mitochondria by autophagy-lysosome pathway, and intra-mitochondrial lipofuscin aggregation may exacerbate mitochondrial abnormalities in mitochondrial myopathy (MM) and mitochondrial disease. We examined vastus lateralis muscle biopsies from 24 patients with pathologically diagnosed MM and clinically diagnosed chronic progressive external ophthalmoplegia, in comparison to the biopsies from 3 other groups:10 patients with inclusion body myositis (IBM), 11 younger adults, and 10 older subjects with no to minimal myopathic changes. Lipofuscin aggregation in muscle fibres was assessed on autofluorescence microscopy, some histochemical stains, and electron microscopy (EM). EM analyses demonstrated intra-mitochondrial lipofuscin aggregates, spherical dense bodies (SDBs), and paracrystalline inclusions (PCIs) which were semi-quantitatively assessed. Intra-mitochondrial lipofuscin aggregates showed no significant differences between groups of MM patients and older subjects or IBM patients, but significant differences between groups of younger adults and others with associated age-related changes. Intra-mitochondrial SDBs were significantly more in MM patients than in older subjects, IBM patients, and younger adults. There was a significant positive correlation between intra-mitochondrial lipofuscin aggregates and SDBs. These findings suggest that intra-mitochondrial formation of lipofuscin SDBs is more in MM and contributing to the pathophysiology of mitochondrial disease.

The Role of Reactive Oxygen Species in the Life Cycle of the Mitochondrion

Currently, it is known that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. It is also known that mitochondria, because of their capacity to produce free radicals, play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including the stimulation of permeability transition pore opening. This process leads to mitoptosis and mitophagy, two sequential processes that are a universal route of elimination of dysfunctional mitochondria and is essential to protect cells from the harm due to mitochondrial disordered metabolism. To date, there is significant evidence not only that the above processes are induced by enhanced reactive oxygen species (ROS) production, but also that such production is involved in the other phases of the mitochondrial life cycle. Accumulating evidence also suggests that these effects are mediated through the regulation of the expression and the activity of proteins that are engaged in processes such as genesis, fission, fusion, and removal of mitochondria. This review provides an account of the developments of the knowledge on the dynamics of the mitochondrial population, examining the mechanisms governing their genesis, life, and death, and elucidating the role played by free radicals in such processes.

Impact of Melatonin on Skeletal Muscle and Exercise

Skeletal muscle disorders are dramatically increasing with human aging with enormous sanitary costs and impact on the quality of life. Preventive and therapeutic tools to limit onset and progression of muscle frailty include nutrition and physical training. Melatonin, the indole produced at nighttime in pineal and extra-pineal sites in mammalians, has recognized anti-aging, anti-inflammatory, and anti-oxidant properties. Mitochondria are the favorite target of melatonin, which maintains them efficiently, scavenging free radicals and reducing oxidative damage. Here, we discuss the most recent evidence of dietary melatonin efficacy in age-related skeletal muscle disorders in cellular, preclinical, and clinical studies. Furthermore, we analyze the emerging impact of melatonin on physical activity. Finally, we consider the newest evidence of the gut-muscle axis and the influence of exercise and probably melatonin on the microbiota. In our opinion, this review reinforces the relevance of melatonin as a safe nutraceutical that limits skeletal muscle frailty and prolongs physical performance.

Combined Aerobic and Resistance Training Increases Stretch- Shortening Cycle Potentiation and Walking Economy in Postmenopausal Women

Purpose

Secondary analyses were performed to test whether combined aerobic and resistance training altered walking economy (i.e., net oxygen uptake) and/or stretch-shortening cycle potentiation (SSCP). A further objective was to determine if walking economy and SSCP were related before or after training.

Methods

Ninety-two postmenopausal women were enrolled wherein 76 completed 16 weeks of supervised aerobic and resistance training. Participants were randomized to one of three training groups based on frequencies: (a) 1 d⋅wk^–1 (n = 23); (b) 2 d⋅wk^–1 (n = 30) or; (c) 3 d⋅wk^–1 (n = 23). Following assessments were performed at baseline and post-training. Indirect calorimetry was used to measure maximal oxygen uptake () and walking economy (submaximal – resting = net ) during a graded exercise test and steady-state treadmill task, respectively. SSCP was determined by measuring the difference between a concentric (CO) and counter-movement (CM) leg press throw.

Results

, walking economy, CO and CM velocity were significantly improved (p < 0.05) for all training groups, however; no time by group interactions were observed. Paired t-tests revealed participants exercise training 2 d⋅wk^–1 exhibited a significant time effect for SSCP (+0.04 ± 0.09 ms^–1; p = 0.03). At baseline, multiple linear regression showed a negative relationship between walking net and SSCP (r = −0.22; p < 0.04) adjusted for relative proportion of  . No such relationship was found post-training.

Conclusion

Among older postmenopausal women, our results indicate that irrespective of frequency of training, 16 weeks of combined aerobic and resistance exercise training increased ease of walking and economy. Additionally, only participants exercising 2 d⋅wk^–1 exhibited significant improvement in SSCP.

Mitochondrial Uncoupling: A Key Controller of Biological Processes in Physiology and Diseases

Mitochondrial uncoupling can be defined as a dissociation between mitochondrial membrane potential generation and its use for mitochondria-dependent ATP synthesis. Although this process was originally considered a mitochondrial dysfunction, the identification of UCP-1 as an endogenous physiological uncoupling protein suggests that the process could be involved in many other biological processes. In this review, we first compare the mitochondrial uncoupling agents available in term of mechanistic and non-specific effects. Proteins regulating mitochondrial uncoupling, as well as chemical compounds with uncoupling properties are discussed. Second, we summarize the most recent findings linking mitochondrial uncoupling and other cellular or biological processes, such as bulk and specific autophagy, reactive oxygen species production, protein secretion, cell death, physical exercise, metabolic adaptations in adipose tissue, and cell signaling. Finally, we show how mitochondrial uncoupling could be used to treat several human diseases, such as obesity, cardiovascular diseases, or neurological disorders.

Nutrition and exercise in Pompe disease

The current standard of care for Pompe disease (PD) is the administration of enzyme replacement therapy (ERT). Exercise and nutrition are often considered as complementary strategies rather than "treatments" per se. Nutritional assessment is important in patients with locomotor disability because the relative hypodynamia limits energy expenditure and thus the total amount of energy must be reduced to avoid obesity. A lower total energy intake often leads to lower protein and micronutrient intake. Consequently, ensuring that Pompe patients are tested for and replaced for deficiencies (protein, vitamin D, vitamin B12, etc.) is an important aspect of care. Furthermore, given the role of autophagy in the pathophysiology of PD and the fact that fasting induces autophagy, it is important that strategies such as nutritional timing and amino acid intake (L-arginine, L-leucine) be evaluated as therapies. Exercise interventions have been shown to improve six-minute walk testing distance by more than what was seen in the seminal ERT study in late-onset PD. Exercise therapy can also activate autophagy, and this is likely another component of its efficacy. The current review will evaluate the theoretical and practical aspects of nutrition and exercise as therapies for patients with PD.