Post-stroke fatigue as an indicator of underlying bioenergetics alterations

Energy metabolism in health and diseases

Energy metabolism is indispensable for sustaining physiological functions in living organisms and assumes a pivotal role across physiological and pathological conditions. This review provides an extensive overview of advancements in energy metabolism research, elucidating critical pathways such as glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism, along with their intricate regulatory mechanisms. The homeostatic balance of these processes is crucial; however, in pathological states such as neurodegenerative diseases, autoimmune disorders, and cancer, extensive metabolic reprogramming occurs, resulting in impaired glucose metabolism and mitochondrial dysfunction, which accelerate disease progression. Recent investigations into key regulatory pathways, including mechanistic target of rapamycin, sirtuins, and adenosine monophosphate-activated protein kinase, have considerably deepened our understanding of metabolic dysregulation and opened new avenues for therapeutic innovation. Emerging technologies, such as fluorescent probes, nano-biomaterials, and metabolomic analyses, promise substantial improvements in diagnostic precision. This review critically examines recent advancements and ongoing challenges in metabolism research, emphasizing its potential for precision diagnostics and personalized therapeutic interventions. Future studies should prioritize unraveling the regulatory mechanisms of energy metabolism and the dynamics of intercellular energy interactions. Integrating cutting-edge gene-editing technologies and multi-omics approaches, the development of multi-target pharmaceuticals in synergy with existing therapies such as immunotherapy and dietary interventions could enhance therapeutic efficacy. Personalized metabolic analysis is indispensable for crafting tailored treatment protocols, ultimately providing more accurate medical solutions for patients. This review aims to deepen the understanding and improve the application of energy metabolism to drive innovative diagnostic and therapeutic strategies.

Excessive Daytime Sleepiness, Inflammation, and Platelet Energy Metabolism in Chronic Stroke Survivors: A Pilot Study

BACKGROUND

Excessive daytime sleepiness is a prevalent and sustained symptom that contributes to untoward physiological and psychological outcomes among stroke survivors. Mechanisms of excessive daytime sleepiness poststroke are not fully understood. Chronic systemic inflammation may contribute to impaired mitochondrial functioning and thereby reduce cellular energy metabolism, which may contribute to symptoms of excessive daytime sleepiness in stroke survivors.

OBJECTIVES

This pilot study aimed to assess the relationship between systemic inflammation and cellular energy metabolism to poststroke excessive daytime sleepiness.

METHODS

This descriptive pilot study explored the relationship between excessive daytime sleepiness, systemic inflammation, and aerobic energy metabolism of platelets in 22 chronic stroke survivors. The Epworth Sleepiness Scale was used to measure excessive daytime sleepiness. Systemic inflammation was measured by assessing pro-inflammatory cytokines interleukin-6, interleukin-1β, and tumor necrosis factor-alpha and the inflammatory marker C-reactive protein. Aerobic energy metabolism was measured by assessing oxygen consumption rates of platelets. Simple linear regression was used to test the influence of oxygen consumption rates and inflammation on excessive daytime sleepiness. Correlations were analyzed using Spearman rho correlation coefficients.

RESULTS

Excessive daytime sleepiness was recognized in 27.3% of the sample. Systemic inflammation was associated with excessive daytime sleepiness in women but not men. We found no significant relationship between excessive daytime sleepiness and energy metabolism of platelets. However, all oxygen consumption rates were numerically higher in persons with excessive daytime sleepiness.

DISCUSSION

Systemic inflammation may be related to excessive daytime sleepiness symptoms with a notable effect among women. Future larger studies are needed to further explore the sexually dimorphic relationship of poststroke excessive daytime sleepiness to systemic inflammation. Numerically higher platelet oxygen consumption rates may indicate higher energy demands for stroke survivors with excessive daytime sleepiness.

Heart failure related fatigue: An exploratory analysis of serum osmolality from the national health and nutrition examination survey

BACKGROUND

Fatigue is a prominent symptom of heart failure (HF). However, underlying mechanisms remain poorly understood. Fluid volume status has been suggested as a physiologic mechanism of HF-related fatigue. Serum osmolality may fluctuate with changes in volume status associated with neurohormonal dysregulation. The relationship of fatigue to serum osmolality has not been assessed in adults with HF.

OBJECTIVES

Describe the relationship between serum osmolality and fatigue in adults with HF.

METHODS

We analyzed two waves of cross-sectional data from the National Health and Nutrition Examination Survey (2015-2016 and 2017-2018). Adults who self-reported having HF without select co-morbid conditions known to contribute to fatigue were included. Data were weighted to provide US national estimates, and complex sample design used for analyses. Sequential logistic regression was used to isolate the effect of serum osmolality on the odds of having fatigue.

RESULTS

Data from the sample represented 1.4 million Americans with HF (58.5 % male; median age 68 years), of whom 1,001,589 (67.9 %) reported fatigue. Participants with fatigue had lower serum osmolality compared to those without fatigue (t = -3.04, p = .009). Higher serum osmolality was associated with 8.8 % lower odds of experiencing fatigue when controlling for sex and body mass index (OR = 0.912, p = .007, CI 0.857 - 0.972).

CONCLUSIONS

HF-related fatigue is associated with lower serum osmolality. Low serum osmolality may indicate excess volume and the presence of a heightened neurohormonal response, both of which may influence fatigue. Alternatively, serum osmolality may directly affect other physiologic changes that may contribute to fatigue.

A systematic review of post-stroke fatigue measurement scale based on COSMIN guidelines

Objective

This study aimed to evaluate the methodological quality and measurement attribute quality of the post-stroke fatigue measurement scale, so as to provide some basis for the clinical application and promotion of related scales.

Methods

The Chinese National Knowledge Infrastructure, the Wanfang Data Knowledge Service Platform, the China Science and Technology Journal Database, the Chinese Medical Journal Full-text Database, the Chinese Biology Medicine, PubMed, Embase, Medline, the Cochrane Library, the Web of Science, CINAHL, and PsycINFO databases were searched for literature on the post-stroke fatigue measurement scale up to June 2022. Literature screening and data extraction were carried out independently by two researchers, and in the case of disagreement, discussions were held with a third investigator to reach an agreement, and the COSMIN checklist and criteria were used to systematically evaluate the attributes of the measurement scale.

Results

A total of 17 studies were included, involving 10 post-stroke fatigue measurement scales. The content validity of FSS-7, FACIT-F, NRS-FRS, and MFI-20 was "not mentioned," and the remaining scales were "uncertain." In terms of construct validity, MFS was "adequate"; FSS-7, FACIT-F, and NRS-FRS were "not mentioned"; and the remaining scales were "uncertain." In terms of internal consistency, NRS-FRS was "not mentioned"; FSS and MFS were "adequate"; and the remaining scales were "uncertain." In terms of hypothesis testing, CIS and FACIT-F were "not mentioned," NRS-FRS was "adequate," and the remaining scales were "uncertain." The stability of FSS-7, CIS, FACIT-F, and MFI-20 was "not mentioned," and the remaining scales were "adequate." The cross-cultural validity of FSS-7 was "adequate," and the remaining scales were "not mentioned." All 10 scales were given a recommendation grade of "B".

Conclusion

For the time being, the FSS can be recommended to measure post-stroke fatigue, but it still needs to be tested for more relevant measurement properties in order to gain more support from high-quality evidence. For a more comprehensive assessment of post-stroke fatigue, the FIS, FAS, and NFI-stroke should perhaps be considered, as the FSS is a one-dimensional scale that can only measure physical fatigue in patients; however, these scales also need to be tested for more relevant measurement properties to verify their clinical applicability.

A roadmap for research in post-stroke fatigue: Consensus-based core recommendations from the third Stroke Recovery and Rehabilitation Roundtable

RATIONALE

Fatigue affects almost half of all people living with stroke. Stroke survivors rank understanding fatigue and how to reduce it as one of the highest research priorities.

METHODS

We convened an interdisciplinary, international group of clinical and pre-clinical researchers and lived experience experts. We identified four priority areas: (1) best measurement tools for research, (2) clinical identification of fatigue and potentially modifiable causes, (3) promising interventions and recommendations for future trials, and (4) possible biological mechanisms of fatigue. Cross-cutting themes were aphasia and the voice of people with lived experience. Working parties were formed and structured consensus building processes were followed.

RESULTS

We present 20 recommendations covering outcome measures for research, development, and testing of new interventions and priority areas for future research on the biology of post-stroke fatigue. We developed and recommend the use of the Stroke Fatigue Clinical Assessment Tool.

CONCLUSIONS

By synthesizing current knowledge in post-stroke fatigue across clinical and pre-clinical fields, our work provides a roadmap for future research into post-stroke fatigue.

Mechanisms of Post-Stroke Fatigue: A Follow-Up From the Third Stroke Recovery and Rehabilitation Roundtable

BACKGROUND

Post-stroke fatigue (PSF) is a significant and highly prevalent symptom, whose mechanisms are poorly understood. The third Stroke Recovery and Rehabilitation Roundtable paper on PSF focussed primarily on defining and measuring PSF while mechanisms were briefly discussed. This companion paper to the main paper is aimed at elaborating possible mechanisms of PSF.

METHODS

This paper reviews the available evidence that potentially explains the pathophysiology of PSF and draws parallels from fatigue literature in other conditions. We start by proposing a case for phenotyping PSF based on structural, functional, and behavioral characteristics of PSF. This is followed by discussion of a potentially significant role of early inflammation in the development of fatigue, specifically the impact of low-grade inflammation and its long-term systemic effects resulting in PSF. Of the many neurotransmitter systems in the brain, the dopaminergic systems have the most evidence for a role in PSF, along with a role in sensorimotor processing. Sensorimotor neural network dynamics are compromised as highlighted by evidence from both neurostimulation and neuromodulation studies. The double-edged sword effect of exercise on PSF provides further insight into how PSF might emerge and the importance of carefully titrating interventional paradigms.

CONCLUSION

The paper concludes by synthesizing the presented evidence into a unifying model of fatigue which distinguishes between factors that pre-dispose, precipitate, and perpetuate PSF. This framework will help guide new research into the biological mechanisms of PSF which is a necessary prerequisite for developing treatments to mitigate the debilitating effects of post-stroke fatigue.

A roadmap for research in post-stroke fatigue: Consensus-based core recommendations from the third Stroke Recovery and Rehabilitation Roundtable

RATIONALE

Fatigue affects almost half of all people living with stroke. Stroke survivors rank understanding fatigue and how to reduce it as one of the highest research priorities.

METHODS

We convened an interdisciplinary, international group of clinical and pre-clinical researchers and lived experience experts. We identified four priority areas: (1) best measurement tools for research, (2) clinical identification of fatigue and potentially modifiable causes, (3) promising interventions and recommendations for future trials, and (4) possible biological mechanisms of fatigue. Cross-cutting themes were aphasia and the voice of people with lived experience. Working parties were formed and structured consensus building processes were followed.

RESULTS

We present 20 recommendations covering outcome measures for research, development, and testing of new interventions and priority areas for future research on the biology of post-stroke fatigue. We developed and recommend the use of the Stroke Fatigue Clinical Assessment Tool.

CONCLUSIONS

By synthesizing current knowledge in post-stroke fatigue across clinical and pre-clinical fields, our work provides a roadmap for future research into post-stroke fatigue.

Remote ischaemic conditioning for fatigue after stroke (RICFAST): A pilot randomised controlled trial

BACKGROUND

Post stroke fatigue (PSF) affects 50 % of stroke survivors, and can be disabling. Remote ischaemic conditioning (RIC), can preserve mitochondrial function, improve tissue perfusion and may mitigate PSF. This pilot randomised controlled trial evaluates the safety and feasibility of using RIC for PSF and evaluated measures of cellular bioenergetics.

METHODS

24 people with debilitating PSF (7 item Fatigue Severity Score, FSS-7 > 4) were randomised (1:1) in this single-centre phase 2 study to RIC (blood pressure cuff inflation around the upper arm 200 mmHg for 5 min followed by 5 min of deflation), or sham (inflation pressure 20 mmHg), repeated 4 cycles, 3 times per week for 6 weeks. Primary outcomes were safety, acceptability, and compliance. Secondary outcomes included FSS-7, 6 min walking test (6MWT), peak oxygen consumption (V̇O2peak), ventilatory anaerobic threshold (VAT), and muscle adenosine triphosphate (ATP) content measured using 31-phosphorous magnetic resonance spectroscopy of tibialis anterior.

RESULTS

RIC was safe (no serious adverse events, adverse events mild) and adherence excellent (91 % sessions completed). Exploratory analysis revealed lower FSS-7 scores in the RIC group compared to sham at 6 weeks (between group difference FSS-7 -0.7, 95 %CI -2.0 to 0.6), 3 months (-1.0, 95 %CI -2.2 to 0.2) and 6 months (-0.9, 95 %CI -2.0 to 0.2). There were trends towards increased VAT, increased muscle ATP content and improved 6MWT in the RIC group.

DISCUSSION

RIC is safe and acceptable for people with PSF and may result in clinically meaningful improvements in fatigue and muscle bioenergetics that require further investigation in larger studies.

Blood-based bioenergetics: a liquid biopsy of mitochondrial dysfunction in disease

Mitochondria operate as hubs of cellular metabolism that execute important regulatory functions. Damaged/dysfunctional mitochondria are recognized as major pathogenic contributors to many common human diseases. Assessment of mitochondrial function relies upon invasive tissue biopsies; peripheral blood cells, specifically platelets, have emerged as an ideal candidate for mitochondrial function assessment. Accessibility and documented pathology-related dysfunction have prompted investigation into the role of platelets in disease, the contribution of platelet mitochondria to pathophysiology, and the capacity of platelets to reflect systemic mitochondrial health. Platelet mitochondrial bioenergetics are being investigated in neurodegenerative and cardiopulmonary diseases, infection, diabetes, and other (patho)physiological states such as aging and pregnancy. Early findings support the use of platelets as a biomarker for mitochondrial functional health.

Online advice for the symptomatic management of post-stroke fatigue: A scoping review

BACKGROUND

Limited medical evidence for managing post-stroke fatigue leads stroke survivors to seek information through other sources. This scoping review aimed to identify and assess the range and quality of web-based recommendations for managing post-stroke fatigue.

METHODS

Publicly accessible websites providing advice for post-stroke fatigue management were considered for review using the Joanna Briggs Institute's methodology. Using the search term "fatigue stroke", the first two pages of results from each search engine (Google, Yahoo, and Bing) were assessed against predetermined criteria. Findings were reported in accordance with PRISMA-ScR checklist. Quality and readability were also assessed.

RESULTS

Fifty-seven websites were identified; 16 primary and 11 linked websites met the inclusion criteria and demonstrated moderate to high quality and high readability. Primary websites were curated by non-government organizations (n = 10/16), companies (n = 4/16) or were media and blog websites (n = 2/16). Additional resources were provided on linked websites. All websites provided non-pharmacological advice, with four also describing pharmacological management. Many websites included advice related to physical activity modification (n = 18/27) and energy conservation strategies (e.g. activity prioritization, planning, pacing) (n = 26/27). Direction to seek health professional advice appeared frequently (n = 16/27).

CONCLUSIONS

The quality of publicly available web-based advice for people with post-stroke fatigue was moderate to high in most websites, with high readability. Energy conservation strategies and physical activity modification appear frequently. The general nature of the advice provided on most websites is supported by direction to healthcare professionals (i.e., clinical referral) who may assist in the practical individualization of strategies for managing post-stroke fatigue.

Exploratory Analysis of Associations Between Whole Blood Mitochondrial Gene Expression and Cancer-Related Fatigue Among Breast Cancer Survivors

BACKGROUND

Cancer-related fatigue is a prevalent, debilitating, and persistent condition. Mitochondrial dysfunction is a putative contributor to cancer-related fatigue, but relationships between mitochondrial function and cancer-related fatigue are not well understood.

OBJECTIVES

We investigated the relationships between mitochondrial DNA (mtDNA) gene expression and cancer-related fatigue, as well as the effects of fish and soybean oil supplementation on these relationships.

METHODS

A secondary analysis was performed on data from a randomized controlled trial of breast cancer survivors 4-36 months posttreatment with moderate-severe cancer-related fatigue. Participants were randomized to take 6 g fish oil, 6 g soybean oil, or 3 g each daily for 6 weeks. At pre- and postintervention, participants completed the Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire and provided whole blood for assessment of mtDNA gene expression. The expression of 12 protein-encoding genes was reduced to a single dimension using principal component analysis for use in regression analysis. Relationships between mtDNA expression and cancer-related fatigue were assessed using linear regression.

RESULTS

Among 68 participants, cancer-related fatigue improved and expression of all mtDNA genes decreased over 6 weeks with no effect of treatment group on either outcome. Participants with lower baseline mtDNA gene expression had greater improvements in cancer-related fatigue. No significant associations were observed between mtDNA gene expression and cancer-related fatigue at baseline or changes in mtDNA gene expression and changes in cancer-related fatigue.

DISCUSSION

Data from this exploratory study add to the growing literature that mitochondrial dysfunction may contribute to the etiology and pathophysiology of cancer-related fatigue.

Elevated plasma high-sensitivity C-reactive protein at admission predicts the occurrence of post-stroke fatigue at 6 months after ischaemic stroke

BACKGROUND AND PURPOSE

Post-stroke fatigue (PSF) is a common neuropsychiatric affective symptom occurring after stroke. Evidence indicates activated inflammatory pathways are involved in modulating the stroke and fatigue. High-sensitivity C-reactive protein (hs-CRP) is one of the most sensitive indicators of inflammation. Our aim was to estimate the association between plasma hs-CRP and PSF after acute ischaemic stroke.

METHODS

In all, 212 acute ischaemic stroke patients were consecutively recruited within the first 14 days after stroke onset and followed up for 6 months. Plasma hs-CRP levels were assayed by enzyme linked immunosorbent assay. Fatigue severity was assessed using the Fatigue Scale for Motor and Cognitive Functions. A score ≥ 43 is defined as PSF.

RESULTS

Sixty-eight stroke patients (32.1%) were diagnosed with PSF at 6 months' follow-up. In the patients with PSF, plasma hs-CRP levels were significantly higher compared with those in non-PSF patients (t = -8.524, P ≤ 0.001). In multivariate analyses, plasma levels of hs-CRP were independently associated with PSF at 6 months (odds ratio 3.435, 95% confidence interval 2.222-5.309; P ≤ 0.001) after adjusting other recorded variables. Based on the receiver operating characteristic curve, the optimal cut-off value of plasma hs-CRP levels as an indicator for the prediction of PSF was projected to be 0.52 mg/dl, which yielded a sensitivity of 77.9% and a specificity of 74.3%, with the area under the curve 0.794 (95% confidence interval 0.725-0.864; P ≤ 0.001).

CONCLUSION

Elevated plasma hs-CRP levels at admission were associated with PSF 6 months after stroke, suggesting that these alterations might predict the development of PSF in stroke patients.