Adverse Neurological Effects of Short-Term Sleep Deprivation in Aging Mice Are Prevented by SS31 Peptide

Relationship between sleep, physical fitness, brain microstructure, and cognition in healthy older adults: A pilot study

BACKGROUND

There is a critical need for neuroimaging markers of brain integrity to monitor effects of modifiable lifestyle factors on brain health. This observational, cross-sectional study assessed relationships between brain microstructure and sleep, physical fitness, and cognition in healthy older adults.

METHODS

Twenty-three adults aged 60 and older underwent whole-brain multi-shell diffusion imaging, comprehensive cognitive testing, polysomnography, and exercise testing. Neurite Orientation Dispersion and Density Imaging (NODDI) was used to quantify neurite density (NDI) and orientation dispersion (ODI). Diffusion tensor imaging (DTI) was used to quantify axial diffusivity (AxD), fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD). Relationships between sleep efficiency (SE), time and percent in N3 sleep, cognitive function, physical fitness (VO2 peak) and the diffusion metrics in regions of interest and the whole brain were evaluated.

RESULTS

Higher NDI in bilateral white and gray matter was associated with better executive functioning. NDI in the right anterior cingulate and adjacent white matter was positively associated with language skills. Higher NDI in the left posterior corona radiata was associated with faster processing speed. Physical fitness was positively associated with NDI in the left precentral gyrus and corticospinal tract. N3 % was positively associated with NDI in the left caudate and right pre- and postcentral gyri. Higher ODI in the left putamen and adjacent white matter was associated with better executive function.

CONCLUSION

NDI and ODI derived from NODDI are potential neuroimaging markers for associations between brain microstructure and modifiable risk factors in aging. If these associations are observable in clinical samples, NODDI could be incorporated into clinical trials assessing the effects of modifiable risk factors on brain integrity in aging and neurodegenerative diseases.

Skeletal muscle mitochondrial dysfunction mediated by Pseudomonas aeruginosa quorum-sensing transcription factor MvfR: reversing effects with anti-MvfR and mitochondrial-targeted compounds

Sepsis and chronic infections with Pseudomonas aeruginosa, a leading "ESKAPE" bacterial pathogen, are associated with increased morbidity and mortality and skeletal muscle atrophy. The actions of this pathogen on skeletal muscle remain poorly understood. In skeletal muscle, mitochondria serve as a crucial energy source, which may be perturbed by infection. Here, using the well-established backburn and infection model of murine P. aeruginosa infection, we deciphered the systemic impact of the quorum-sensing transcription factor MvfR (multiple virulence factor regulator) by interrogating, 5 days post-infection, its effect on mitochondrial-related functions in the gastrocnemius skeletal muscle and the outcome of the pharmacological inhibition of MvfR function and that of the mitochondrial-targeted peptide, Szeto-Schiller 31 (SS-31). Our findings show that the MvfR perturbs adenosine triphosphate generation, oxidative phosphorylation, and antioxidant response, elevates the production of reactive oxygen species, and promotes oxidative damage of mitochondrial DNA in the gastrocnemius muscle of infected mice. These impairments in mitochondrial-related functions were corroborated by the alteration of key mitochondrial proteins involved in electron transport, mitochondrial biogenesis, dynamics and quality control, and mitochondrial uncoupling. Pharmacological inhibition of MvfR using the potent anti-MvfR lead, D88, we developed, or the mitochondrial-targeted peptide SS-31 rescued the MvfR-mediated alterations observed in mice infected with the wild-type strain PA14. Our study provides insights into the actions of MvfR in orchestrating mitochondrial dysfunction in the skeletal murine muscle, and it presents novel therapeutic approaches for optimizing clinical outcomes in affected patients.

IMPORTANCE

Skeletal muscle, pivotal for many functions in the human body, including breathing and protecting internal organs, contains abundant mitochondria essential for maintaining cellular homeostasis during infection. The effect of Pseudomonas aeruginosa (PA) infections on skeletal muscle remains poorly understood. Our study delves into the role of a central quorum-sensing transcription factor, multiple virulence factor regulator (MvfR), that controls the expression of multiple acute and chronic virulence functions that contribute to the pathogenicity of PA. The significance of our study lies in the role of MvfR in the metabolic perturbances linked to mitochondrial functions in skeletal muscle and the effectiveness of the novel MvfR inhibitor and the mitochondrial-targeted peptide SS-31 in alleviating the mitochondrial disturbances caused by PA in skeletal muscle. Inhibiting MvfR or interfering with its effects can be a potential therapeutic strategy to curb PA virulence.

Research on the anti-aging mechanisms of Panax ginseng extract in mice: a gut microbiome and metabolomics approach

Introduction: Aged-related brain damage and gut microbiome disruption are common. Research affirms that modulating the microbiota-gut-brain axis can help reduce age-related brain damage. Methods: Ginseng, esteemed in traditional Chinese medicine, is recognized for its anti-aging capabilities. However, previous Ginseng anti-aging studies have largely focused on diseased animal models. To this end, efforts were hereby made to explore the potential neuroprotective effects of fecal microbiota transplantation (FMT) from Ginseng-supplemented aged mice to those pre-treated with antibiotics. Results: As a result, FMT with specific modifications in natural aging mice improved animal weight gain, extended the telomere length, anti-oxidative stress in brain tissue, regulated the serum levels of cytokine, and balanced the proportion of Treg cells. Besides, FMT increased the abundance of beneficial bacteria of Lachnospiraceae, Dubosiella, Bacteroides, etc. and decreased the levels of potential pathogenic bacteria of Helicobacter and Lachnoclostridium in the fecal samples of natural aged mice. This revealed that FMT remarkably reshaped gut microbiome. Additionally, FMT-treated aged mice showed increased levels of metabolites of Ursolic acid, β-carotene, S-Adenosylmethionine, Spermidine, Guanosine, Celecoxib, Linoleic acid, etc., which were significantly positively correlated with critical beneficial bacteria above. Additionally, these identified critical microbiota and metabolites were mainly enriched in the pathways of Amino acid metabolism, Lipid metabolism, Nucleotide metabolism, etc. Furthermore, FMT downregulated p53/p21/Rb signaling and upregulated p16/p14, ATM/synapsin I/synaptophysin/PSD95, CREB/ERK/AKT signaling in brain damage following natural aging. Discussion: Overall, the study demonstrates that reprogramming of gut microbiota by FMT impedes brain damage in the natural aging process, possibly through the regulation of microbiota-gut-brain axis.

Skeletal Muscle Mitochondrial Dysfunction Mediated by Pseudomonas aeruginosa Quorum Sensing Transcription Factor MvfR: Reversing Effects with Anti-MvfR and Mitochondrial-Targeted Compounds

Sepsis and chronic infections with Pseudomonas aeruginosa, a leading "ESKAPE" bacterial pathogen, are associated with increased morbidity and mortality and skeletal muscle atrophy. The actions of this pathogen on skeletal muscle remain poorly understood. In skeletal muscle, mitochondria serve as a crucial energy source, which may be perturbed by infection. Here, using the well-established backburn and infection model of murine P. aeruginosa infection, we deciphered the systemic impact of the quorum sensing (QS) transcription factor MvfR by interrogating five days post-infection its effect on mitochondrial-related functions in the gastrocnemius skeletal muscle and the outcome of the pharmacological inhibition of MvfR function and that of the mitochondrial-targeted peptide, Szeto-Schiller 31 (SS-31). Our findings show that the MvfR perturbs ATP generation, oxidative phosphorylation (OXPHOS), and antioxidant response, elevates the production of reactive oxygen species, and promotes oxidative damage of mitochondrial DNA in the gastrocnemius muscle of infected mice. These impairments in mitochondrial-related functions were corroborated by the alteration of key mitochondrial proteins involved in electron transport, mitochondrial biogenesis, dynamics and quality control, and mitochondrial uncoupling. Pharmacological inhibition of MvfR using the potent anti-MvfR lead, D88, we developed, or the mitochondrial-targeted peptide SS-31 rescued the MvfR- mediated alterations observed in mice infected with the wild-type strain PA14. Our study provides insights into the actions of MvfR in orchestrating mitochondrial dysfunction in the skeletal murine muscle, and it presents novel therapeutic approaches for optimizing clinical outcomes in affected patients.

Application research of novel peptide mitochondrial-targeted antioxidant SS-31 in mitigating mitochondrial dysfunction

Due to the pivotal role of mitochondria in the generation of adenosine triphosphate (ATP) and the regulation of cellular homeostasis, mitochondrial dysfunction may exert a profound impact on various physiological systems, potentially precipitating a spectrum of distinct diseases. Consequently, research pertaining to mitochondrial therapeutics has assumed increasing significance, warranting heightened scrutiny. In recent years, the field of mitochondrial therapy has witnessed noteworthy advancements, with active exploration into diverse pharmacological agents aimed at ameliorating mitochondrial function. Elamipretide (SS-31), a novel synthetic mitochondrial-targeted antioxidant, has emerged as a promising candidate with extensive therapeutic potential. Its notable attributes encompass the mitigation of oxidative stress, the suppression of inflammatory processes, the maintenance of mitochondrial dynamics, and the prevention of cellular apoptosis. As such, SS-31 may emerge as a viable choice for the treatment of mitochondrial dysfunction-related ailments in the foreseeable future. This article extensively expounds upon the superiority of SS-31 over natural antioxidants and traditional mitochondrial-targeted antioxidants, delves into its mechanisms of modulating mitochondrial function, and comprehensively summarizes its applications in alleviating mitochondrial dysfunction-associated disorders. Furthermore, we offer a comprehensive outlook on the expansive prospects of SS-31's future development and application.

The Interaction Effect of Sleep Deprivation and Treadmill Exercise in Various Durations on Spatial Memory with Respect to the Oxidative Status of Rats

Sleep deprivation (SD) has deleterious effects on cognitive functions including learning and memory. However, some studies have shown that SD can improve cognitive functions. Interestingly, treadmill exercise has both impairment and improvement effects on memory function. In this study, we aimed to investigate the effect of SD for 4 (short-term) and 24 (long-term) hours, and two protocols of treadmill exercise (mild short-term and moderate long-term) on spatial memory performance, and oxidative and antioxidant markers in the serum of rats. Morris Water Maze apparatus was used to assess spatial memory performance. Also, SD was done using gentle handling method. In addition, the serum level of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) was measured. The results showed that 24 h SD (but not 4 h) had negative effect on spatial memory performance, decreased SOD, CAT, and GSH-Px level, and increased MDA level. Long-term moderate (but not short-term mild) treadmill exercise had also negative effect on spatial memory performance, decreased SOD, CAT, and GSH-Px level, and increased MDA level. Interestingly, both protocols of treadmill exercise reversed spatial memory impairment and oxidative stress induced by 24 h SD. In conclusion, it seems that SD and treadmill exercise interact with each other, and moderate long-term exercise can reverse the negative effects of long-term SD on memory and oxidative status; although, it disrupted memory function and increased oxidative stress by itself.

The impact of insomnia on frailty and the hallmarks of aging

Throughout the course of life, there are age-related changes in sleep. Despite these normal changes, there is a high percentage of older adults that report sleep dissatisfaction with a high pervasiveness of chronic insomnia, the most common sleep disorder worldwide, with its prevalence being expected to continuously increase due to the growing rates of aging and obesity. This can have different adverse health outcomes, especially by promoting both physical and cognitive decline, which ultimately may aggravate frailty in older adults. Moreover, age-related frailty and sleep dysfunction may have a common mechanism related to the hallmarks of cellular aging. Cellular aging was categorized into nine hallmarks, such as DNA damage, telomere attrition and epigenetic changes. In the context of geriatric and chronic insomnia research, this review aims at discussing the current evidence from both animal models and human cohorts addressing the link between chronic insomnia, the hallmarks of aging and their impact on frailty. Moreover, the most recent research about the putative effect of insomnia therapeutic approaches on hallmarks of aging will be also highlighted.

Long-term treatment with Elamipretide enhances healthy aging phenotypes in mice

Background

Disruption of metabolic and bioenergetic homeostasis related to mitochondrial dysfunction is a key driver of aging biology. Therefore, targeting mitochondrial function would be a rational approach to slowing aging. Elamipretide (Elam, a.k.a. SS-31) is a peptide known to target mitochondria and suppress mammalian signs of aging. The present study was designed to examine the phenotypic effects of long-term Elam treatment on aging in C57BL/6 mice starting at 18 months of age.

Methods

Mice were fed regular chow (RC diet) or a diet high in fat and sugar (HF diet) and treated with 3 mg/kg of Elam or saline subcutaneously 5 days per week for 10 months. Physiological performance assessments were conducted at 28 months of age.

Results

Elam improved the physical performance of males but not females, while in females Elam improved cognitive performance and enhanced the maintenance of body weight and fat mass. It also improved diastolic function in both males and females, but to a greater extent in males. The HF diet over 10 months had a negative effect on health span, as it increased body fat and decreased muscle strength and heart function, especially in females.

Conclusions

Elam enhanced healthy aging and cardiac function in both male and female mice, although the specific effects on function differed between sexes. In females, the treatment led to better cognitive performance and maintenance of body composition, while in males, performance on a rotating rod was preserved. These overall observations have translational implications for considering additional studies using Elam in therapeutic or preventive approaches for aging and age-related diseases.

Sleep and Alzheimer: The Link

Alzheimer's disease is the most common type of dementia which has both cognitive and non-cognitive disabilities. Recent research has proved that sleep deprivation and insomnia have been related to the pathophysiology of Alzheimer's disease and would influence the symptoms and progression of the disease. We look at the current research that supports the idea that the lack of sleep relates to cognitive decline and dementia, with an emphasis on Alzheimer's disease. We integrated the various possible mechanisms of sleep deprivation leading to Alzheimer's disease and cognitive decline. The role of neuroinflammation, generation of reactive oxidative species and sleep disturbances play a central role in tau generation and Aβ deposition. An approach to manage sleep changes can widely prevent the cognitive decline of Alzheimer's disease.

Resilience to aging is a heterogeneous characteristic defined by physical stressors

Physical resilience, the capacity to respond to and recover from a stressful event, declines with advancing age. Individuals respond differently to physical stressors across their lifespans. While the biological underpinnings of resilience remain unclear, a plausible determinant is the capacity of an individual's cellular and molecular levels to return to homeostasis after a physical challenge. Impaired resilience may not only be a consequence of aging but could also be a contributing factor to the aging process. Therefore, resilience at relatively younger ages could be predictive of future health and lifespan. By utilizing standardized physical challenges and measuring stress response patterns, the relative resilience of individuals can be quantified and classified. Current preclinical research suggests that several physical stressors could be used to measure resilience in clinical aging studies. A mechanistic understanding of why some individuals are more resilient to physical stressors than others could help identify protective factors and therapeutic ways to promote healthy aging.