Tag: oxidative stress

Altered Lipid, Energy Metabolism and Oxidative Stress Are Common Features in a Range of Chronic Conditions

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Gulf War Syndrome (GWS) and Fibromyalgia are chronic illnesses that, despite their prevalence in society, are still of unknown aetiology. All three conditions present similar clinical symptoms and are difficult to diagnose due to a lack of appropriate biomarkers. Currently, diagnosis consists of satisfying clinical criteria and eliminating other conditions, a lengthy and often costly process for patients. The discovery of biomarkers would significantly speed up patient diagnosis and allow the development of pharmacological therapies that target the underlying metabolic causes of these diseases.

Metabolomics is an emerging research area used to characterise the metabolites present within biological specimens. Developments within this field now allow the analysis of thousands of metabolites within different samples and model systems, and have the potential to aid in unravelling the metabolic phenotypes that underpin complex metabolic diseases. ME/CFS, GWS and Fibromyalgia are three conditions that could benefit from a plasma/tissue metabolomics analysis, allowing a greater understanding of their aetiology and identify common pathways. An analysis of the literature in these conditions reveals alterations within pathways associated with energy and lipid metabolism with alterations in key metabolites associated with elevated oxidative stress. Understanding what might drive the elevated oxidative stress within all three illnesses will not only be important in future research but could also be a potential therapeutic target for antioxidant medications which could be implemented to reduce the symptom burden in these illnesses.

Source: MORTEN, Karl Jonathan and Davis, Leah and Lodge, Tiffany A. and Strong, James and Espejo-Oltra, José Andrés and Zalewski, Pawel and Pretorius, Etheresia, Altered Lipid, Energy Metabolism and Oxidative Stress Are Common Features in a Range of Chronic Conditions. Available at SSRN: https://ssrn.com/abstract=4455366 or http://dx.doi.org/10.2139/ssrn.4455366 (Full text available as PDF file)

Ginkgo Biloba and Long COVID: In Vivo and In Vitro Models for the Evaluation of Nanotherapeutic Efficacy

Abstract:

Coronavirus infections are neuroinvasive and can provoke injury to the central nervous system (CNS) and long-term illness consequences. They may be associated with inflammatory processes due to cellular oxidative stress and an imbalanced antioxidant system. The ability of phytochemicals with antioxidant and anti-inflammatory activities, such as Ginkgo biloba, to alleviate neurological complications and brain tissue damage has attracted strong ongoing interest in the neurotherapeutic management of long COVID.
Ginkgo biloba leaf extract (EGb) contains several bioactive ingredients, e.g., bilobalide, quercetin, ginkgolides A–C, kaempferol, isorhamnetin, and luteolin. They have various pharmacological and medicinal effects, including memory and cognitive improvement. Ginkgo biloba, through its anti-apoptotic, antioxidant, and anti-inflammatory activities, impacts cognitive function and other illness conditions like those in long COVID. While preclinical research on the antioxidant therapies for neuroprotection has shown promising results, clinical translation remains slow due to several challenges (e.g., low drug bioavailability, limited half-life, instability, restricted delivery to target tissues, and poor antioxidant capacity).
This review emphasizes the advantages of nanotherapies using nanoparticle drug delivery approaches to overcome these challenges. Various experimental techniques shed light on the molecular mechanisms underlying the oxidative stress response in the nervous system and help comprehend the pathophysiology of the neurological sequelae of SARS-CoV-2 infection.
To develop novel therapeutic agents and drug delivery systems, several methods for mimicking oxidative stress conditions have been used (e.g., lipid peroxidation products, mitochondrial respiratory chain inhibitors, and models of ischemic brain damage). We hypothesize the beneficial effects of EGb in the neurotherapeutic management of long-term COVID-19 symptoms, evaluated using either in vitro cellular or in vivo animal models of oxidative stress.
Source: Akanchise T, Angelova A. Ginkgo Biloba and Long COVID: In Vivo and In Vitro Models for the Evaluation of Nanotherapeutic Efficacy. Pharmaceutics. 2023; 15(5):1562. https://doi.org/10.3390/pharmaceutics15051562 https://www.mdpi.com/1999-4923/15/5/1562 (Full text)

Possible Pathogenesis and Prevention of Long COVID: SARS-CoV-2-Induced Mitochondrial Disorder

Abstract:

Patients who have recovered from coronavirus disease 2019 (COVID-19) infection may experience chronic fatigue when exercising, despite no obvious heart or lung abnormalities. The present lack of effective treatments makes managing long COVID a major challenge.
One of the underlying mechanisms of long COVID may be mitochondrial dysfunction. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can alter the mitochondria responsible for energy production in cells. This alteration leads to mitochondrial dysfunction which, in turn, increases oxidative stress. Ultimately, this results in a loss of mitochondrial integrity and cell death. Moreover, viral proteins can bind to mitochondrial complexes, disrupting mitochondrial function and causing the immune cells to over-react. This over-reaction leads to inflammation and potentially long COVID symptoms.
It is important to note that the roles of mitochondrial damage and inflammatory responses caused by SARS-CoV-2 in the development of long COVID are still being elucidated. Targeting mitochondrial function may provide promising new clinical approaches for long-COVID patients; however, further studies are needed to evaluate the safety and efficacy of such approaches.
Source: Chen T-H, Chang C-J, Hung P-H. Possible Pathogenesis and Prevention of Long COVID: SARS-CoV-2-Induced Mitochondrial Disorder. International Journal of Molecular Sciences. 2023; 24(9):8034. https://doi.org/10.3390/ijms24098034 https://www.mdpi.com/1422-0067/24/9/8034 (Full text)

Astragalus polysaccharide ameliorated complex factor-induced chronic fatigue syndrome by modulating the gut microbiota and metabolites in mice

Abstract:

Chronic fatigue syndrome (CFS) is a debilitating disease with no symptomatic treatment. Astragalus polysaccharide (APS), a component derived from the traditional Chinese medicine A. membranaceus, has significant anti-fatigue activity. However, the mechanisms underlying the potential beneficial effects of APS on CFS remain poorly understood.

A CFS model of 6-week-old C57BL/6 male mice was established using the multiple-factor method. These mice underwent examinations for behavior, oxidative stress and inflammatory indicators in brain and intestinal tissues, and ileum histomorphology. 16 S rDNA sequencing analysis indicated that APS regulated the abundance of gut microbiota and increased production of short chain fatty acids (SCFAs) and anti-inflammatory bacteria.

In addition, APS reversed the abnormal expression of Nrf2, NF-κB, and their downstream factors in the brain-gut axis and alleviated the reduction in SCFAs in the cecal content caused by CFS. Further, APS modulated the changes in serum metabolic pathways induced by CFS.

Finally, it was verified that butyrate exerted antioxidant and anti-inflammatory effects in neuronal cells. In conclusion, APS could increase the SCFAs content by regulating the gut microbiota, and SCFAs (especially butyrate) can further regulate the oxidative stress and inflammation in the brain, thus alleviating CFS.

This study explored the efficacy and mechanism of APS for CFS from the perspective of gut-brain axis and provides a reference to further explore the efficacy of APS and the role of SCFAs in the central nervous system.

Source: Wei X, Xin J, Chen W, Wang J, Lv Y, Wei Y, Li Z, Ding Q, Shen Y, Xu X, Zhang X, Zhang W, Zu X. Astragalus polysaccharide ameliorated complex factor-induced chronic fatigue syndrome by modulating the gut microbiota and metabolites in mice. Biomed Pharmacother. 2023 May 9;163:114862. doi: 10.1016/j.biopha.2023.114862. Epub ahead of print. PMID: 37167729. https://www.sciencedirect.com/science/article/pii/S0753332223006522?via%3Dihub (Full study)

Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a multisystem chronic illness characterized by severe muscle fatigue, pain, dizziness, and brain fog. Many patients with ME/CFS experience orthostatic intolerance (OI), which is characterized by frequent dizziness, light-headedness, and feeling faint while maintaining an upright posture.
Despite intense investigation, the molecular mechanism of this debilitating condition is still unknown. OI is often manifested by cardiovascular alterations, such as reduced cerebral blood flow, reduced blood pressure, and diminished heart rate. The bioavailability of tetrahydrobiopterin (BH4), an essential cofactor of endothelial nitric oxide synthase (eNOS) enzyme, is tightly coupled with cardiovascular health and circulation.
To explore the role of BH4 in ME/CFS, serum samples of CFS patients (n = 32), CFS patients with OI only (n = 10; CFS + OI), and CFS patients with both OI and small fiber polyneuropathy (n = 12; CFS + OI + SFN) were subjected to BH4 ELISA. Interestingly, our results revealed that the BH4 expression is significantly high in CFS, CFS + OI, and CFS + OI + SFN patients compared to age-/gender-matched controls.
Finally, a ROS production assay in cultured microglial cells followed by Pearson correlation statistics indicated that the elevated BH4 in serum samples of CFS + OI patients might be associated with the oxidative stress response. These findings suggest that the regulation of BH4 metabolism could be a promising target for understanding the molecular mechanism of CFS and CFS with OI.
Source: Gottschalk CG, Whelan R, Peterson D, Roy A. Detection of Elevated Level of Tetrahydrobiopterin in Serum Samples of ME/CFS Patients with Orthostatic Intolerance: A Pilot Study. International Journal of Molecular Sciences. 2023; 24(10):8713. https://doi.org/10.3390/ijms24108713 (Full text)

Exploring the Genetic Contribution to Oxidative Stress in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

OBJECTIVES/GOALS: Strong evidence has implicated oxidative stress (OS) as a disease mechanism in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The study aim was to assess whether a C>T single nucleotide polymorphism (SNP) (rs1800668), which reduces the activity of glutathione peroxidase 1 (GPX1), is associated with brain OS in patients with ME/CFS.

METHODS/STUDY POPULATION: Study population: The study enrolled 20 patients with ME/CFS diagnosed according to Canadian Consensus Criteria, and 11 healthy control (HC) subjects. Genotyping: DNA was extracted from whole blood samples, amplified by PCR, and purified. Sanger sequencing was used for genotyping. 1H MRS: Proton magnetic resonance spectroscopy (1H MRS) was used to measure levels of glutathione (GSH) a primary tissue antioxidant and OS marker in a 3x3x2 cm3 occipital cortex (OCC) voxel. GSH spectra were recorded in 15 minutes with the standard J-editing technique. The resulting GSH peak area was normalized to tissue water level in the voxel. Statistical Analysis: T-tests were used to compare OCC GSH levels between ME/CFS and HC groups, and between the study’s genotype groups (group 1: CC, group 2: combined TC and TT).

RESULTS/ANTICIPATED RESULTS: Clinical characteristics: ME/CFS and HC groups were comparable on age and BMI but not on sex (p = 0.038). Genotype frequencies: Genotype frequencies in the ME/CFS group were 0.55 (CC), 0.25 (TC) and 0.2 (TT); and 0.636 (CC), 0.364 (TC), and 0 (TT) in the HC group. GSH levels: There was a trend-level lower mean OCC GSH in ME/CFS than in HC (0.0015 vs 0.0017; p = 0.076). GSH levels by genotype group interaction: Within the ME/CFS group but not in the combined ME/CFS and HC group or HC group alone, GSH levels were lower in the TC and TT genotypes than in CC genotypes (0.00143 vs 0.00164; p = 0.018).

DISCUSSION/SIGNIFICANCE: This study found that the presence of a C>T SNP in GPX1 is associated with lower mean GSH levels and, hence, brain oxidative stress, in ME/CFS patients. If validated in a larger cohort, this finding may support targeted antioxidant therapy based on their genotype as a potentially effective treatment for patients with ME/CFS.

Source: Hampilos, N., Germain, A., Mao, X., Hanson, M., & Shungu, D. (2023). 474 Exploring the Genetic Contribution to Oxidative Stress in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Journal of Clinical and Translational Science, 7(S1), 137-138. doi:10.1017/cts.2023.488. DOI: https://doi.org/10.1017/cts.2023.488

Changes in the State of Vital Systems with Long COVID-19

Abstract:

Long COVID-19 is a chronic disease that continues to be studied. Data on epidemiology and the main symptoms typical for long COVID-19 are presented. Issues related to the pathogenesis of the disease are discussed. At the same time, special attention is paid to the inflammation process (including of the vascular wall endothelium), the state of the immune system (cytokine storm), the hemostasis system (the mechanism for the development of microangiopathy and thrombosis), and oxidative stress. During the analysis, a special place is given to central nervous system disorders (including organic brain damage) and disorders of cognitive functions. In addition, currently known complications from the cardiovascular system and respiratory organs are described. The treatment and rehabilitation of patients with long COVID-19 is not only a medical, but also a significant social problem.

Source: Kuznik, B.I., Shapovalov, K.G. & Chalisova, N.I. Changes in the State of Vital Systems with Long COVID-19. Biol Bull Rev 13, 112–123 (2023). https://doi.org/10.1134/S2079086423020044 (Full text)

Potential Prion Involvement in Long COVID-19 Neuropathology, Including Behavior

Abstract:

Prion is a term used to describe a protein infectious particle responsible for several neurodegenerative diseases in mammals, e.g., Creutzfeldt-Jakob disease. The novelty is that it is protein based infectious agent not involving a nucleic acid genome as found in viruses and bacteria.

Prion disorders exhibit, in part, incubation periods, neuronal loss, and induce abnormal folding of specific normal cellular proteins due to enhancing reactive oxygen species associated with mitochondria energy metabolism. These agents may also induce memory, personality and movement abnormalities as well as depression, confusion and disorientation.

Interestingly, some of these behavioral changes also occur in COVID-19 and mechanistically include mitochondrial damage caused by SARS-CoV-2 and subsequent production of reactive oxygen species. Taken together, we surmise, in part, long COVID may involve the induction of spontaneous prion emergence, especially in individuals susceptible to its origin may thus explain some of its manisfestions post-acute viral infection.

Source: Stefano GB, Büttiker P, Weissenberger S, Anders M, Raboch J, Ptacek R, Kream RM. Potential Prion Involvement in Long COVID-19 Neuropathology, Including Behavior. Cell Mol Neurobiol. 2023 Mar 28:1–6. doi: 10.1007/s10571-023-01342-8. Epub ahead of print. PMID: 36977809; PMCID: PMC10047479. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10047479/ (Full text)

LC, POTS, and ME/CFS: Lifting the Fog

Abstract:

These three syndromes – long covid (LC), postural orthostatic tachycardia syndrome (POTS), and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) – have many symptoms in common. The common denominator remains elusive.
The blood brain barrier (BBB) has been a barrier not only to microbes and toxins but also to understanding pathogenetic links. There are several areas within the brain that have no BBB. These are known as circumventricular organs (CVOs) and their location relative to CNS nuclei that direct autonomic and neuroendocrine functions is provocative in the quest for pathogenesis.
In addition the majority afflicted with LC and ME/CFS appear to be those with two MTHFR polymorphisms, present in over 50% of Americans. These polymorphisms elevate homocysteine. When homocysteine is combined with CVOs, the fog of POTS and its paradox are lifted. POTS may represent the intersection of LC and ME/CFS in those with the MTHFR gene (hypermethylation or 677TT).
The gut microbiomes of LC and ME/CFS, deficient in butyrates, GABA, and diversity, are then linked with MTHFR genotype 677TT. Reactivation of neurotropic EBV and VZV, due to loss of surveillance by CD4+/CD8+ T cells, is seen as secondary. The oxidative stress generated by homocysteine, loss of glutathione, low fiber diet, and persistent chronic inflammation exhaust available mitochondria and, assisted by BKN and estrogen, exacerbate all the elements of these post viral fatigue syndromes.
Source: Chambers, P. LC, POTS, and ME/CFS: Lifting the Fog. Preprints.org 2023, 2023030418. https://doi.org/10.20944/preprints202303.0418.v1 (Full text available as PDF file)

Increased insulin resistance due to Long COVID is associated with depressive symptoms and partly predicted by the inflammatory response during acute infection

Abstract:

Background: Some months after the remission of acute COVID-19, some individuals show depressive symptoms, which are predicted by increased peak body temperature (PBT) and decreased blood oxygen saturation (SpO2). No data indicate whether Long COVID is associated with increased insulin resistance (IR) in association with neuroimmune and oxidative (NIO) processes.

Methods: This case control and retrospective cohort study used the homeostasis Model Assessment 2 (HOMA2) calculator© to compute β-cell function, insulin sensitivity and resistance (HOMA2-IR) and measured the Beck Depression Inventory (BDI) and the Hamilton Depression Rating Scale (HAMD) in 86 Long COVID patients and 39 controls.

Results: Long COVID (3-4 months after the acute infection) is accompanied by increased HOMA2-IR, fasting blood glucose, and insulin levels; 33.7% of the patients versus 0% of the controls had HOMA2-IR values >1.8, suggesting IR. Increased IR was predicted by PBT during acute infection, and associated with depressive symptoms above and beyond the effects of NIO pathways (NLRP3 inflamasome, myeloperoxidase, protein oxidation). There were no significant associations between increased IR and the activated NIO pathways during Long COVID.

Conclusion: Long COVID is associated with new-onset IR which may contribute to the onset of depressive symptoms due to Long COVID by enhancing overall neurotoxicity.

Source: Al-Hakeim HK, Al-Rubaye HT, Jubran AS, Almulla AF, Moustafa SR, Maes M. Increased insulin resistance due to Long COVID is associated with depressive symptoms and partly predicted by the inflammatory response during acute infection. Braz J Psychiatry. 2023 Mar 14. doi: 10.47626/1516-4446-2022-3002. Epub ahead of print. PMID: 36917827. https://pubmed.ncbi.nlm.nih.gov/36917827/