Tag: neuroinflammation

Co-Ultramicronized Palmitoylethanolamide/Luteolin normalizes GABAB-ergic activity and cortical plasticity in long COVID-19 syndrome

Abstract:

Objective: Transcranial magnetic stimulation (TMS) studies showed that patients with cognitive dysfunction and fatigue after COVID-19 exhibit impaired cortical GABAB-ergic activity, as revealed by reduced long-interval intracortical inhibition (LICI).

Aim of this study was to test the effects of co-ultramicronized palmitoylethanolamide/luteolin (PEA-LUT), an endocannabinoid-like mediator able to enhance GABA-ergic transmission and to reduce neuroinflammation, on LICI.

Methods: Thirty-nine patients (26 females, mean age 49.9 ± 11.4 years, mean time from infection 296.7 ± 112.3 days) suffering from persistent cognitive difficulties and fatigue after mild COVID-19 were randomly assigned to receive either PEA-LUT 700mg + 70mg or PLACEBO, administered orally bid for eight weeks. The day before (PRE) and at the end of the treatment (POST), they underwent TMS protocols to assess LICI. We further evaluate short-latency afferent inhibition (SAI) and long-term potentiation (LTP)-like cortical plasticity.

Results: Patients treated with PEA-LUT but not with PLACEBO showed a significant increase of LICI and LTP-like cortical plasticity. SAI remained unaffected.

Conclusions: Eight weeks of treatment with PEA-LUT restore GABAB activity and cortical plasticity in long Covid patients.

Significance: This study confirms altered physiology of the motor cortex in long Covid and indicates PEA-LUT as a candidate for the treatment of this post-viral condition.

Source: Viviana Versace, Paola Ortelli, Sabrina Dezi, Davide Ferrazzoli, Alessia Alibardi, Ilenia Bonini, Michael Engl, Roberto Maestri, Martina Assogna, Valentina Ajello, Elke Pucks-Faes, Leopold Saltuari, Luca Sebastianelli, Markus Kofler, Giacomo Koch. Co-Ultramicronized Palmitoylethanolamide/Luteolin normalizes GABAB-ergic activity and cortical plasticity in long COVID-19 syndrome. Clinical Neurophysiology, 2022, ISSN 1388-2457, https://doi.org/10.1016/j.clinph.2022.10.017. https://www.sciencedirect.com/science/article/pii/S1388245722009385 (Full text)

 

Even mild COVID-19 may have long-term brain impacts

Research presented at the Alzheimer’s Association International Conference suggests even mild cases of COVID-19 may be associated with cognitive deficits months after recovery.

One Argentinian study of 234 seniors who previously had COVID-19 found that more than half showed some degree of cognitive impairment months later. One in three had severe “dementia-like” impairments in memory, attention and executive function — a much higher proportion than the 5%–8% of seniors in the general population who have dementia at a given time.

“This could be the start of a dementia-related epidemic fueled by this latest coronavirus,” stated presenting author Dr. Gabriel de Erausquin of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio. Researchers will follow the study participants over the next three to five years to see if these problems resolve or worsen.

The study didn’t look at participants’ cognitive performance prior to infection. However, those who lost their sense of smell while sick with COVID-19 tended to have more severe cognitive impairments months later, even if their other symptoms had been mild. According to de Erausquin, “once the virus has affected the olfactory bulb and caused effects there — changes that we can see with imaging — then other places in the brain that are connected to it also become abnormal, either in function or structure or both.”

Other research presented linked SARS-CoV-2 infection with an uptick in biomarkers of brain injury, neuroinflammation and Alzheimer disease. One American study of 310 patients with COVID-19 found that those with new neurological symptoms had higher levels of t-tau, NfL, GFAP, pTau-181, and UCH-L1 in their blood, as well as indicators of inflammation such as C-reactive protein, compared to patients without neurological symptoms. “These findings suggest patients who had COVID-19 may have an acceleration of Alzheimer-related symptoms and pathology,” according to presenting author Dr. Thomas Wisniewski of the New York University Grossman School of Medicine.

Earlier this year, de Erausquin and others reported that brain inflammation, stroke and other common complications of viral infections have longstanding links with neurodegenerative disorders. “Therefore, it seems likely to expect that COVID-19-related cardiovascular and cerebrovascular disease will also contribute to a higher longterm risk of cognitive decline and dementia in recovered individuals.”

Several recent studies have documented cognitive deficits post-COVID but like the research presented at the Alzheimer’s Association conference, data on patients’ performance before infection are lacking.

One British study of 81 337 people in EClinicalMedicine found that those who previously had COVID-19 tended to score lower on measures of intelligence, reasoning, problem-solving and planning than people who were never infected.

“These results accord with reports of long-COVID, where ‘brain fog,’ trouble concentrating and difficulty finding the correct words are common,” according to the authors. People who had been hospitalized and put on ventilators had the greatest impairments, but even those who had relatively mild symptoms showed some deficit.

In another study of 57 Americans receiving inpatient rehabilitation after hospitalization for COVID-19, four in five had mild to severe cognitive impairments. More than half had deficits in working memory, while two in five had impaired processing speed, divided attention, and trouble switching between mental tasks.

Similar deficits have also been noted in patients after recovery from other coronaviruses. A 2020 systematic review and meta-analysis found that delirium was common in the acute stage of severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and COVID-19. Following up with patients six weeks to 39 months later, more than 15% reported sleep disorders, mood swings, trouble concentrating, impaired memory and other mental challenges.

Based on this growing body of evidence, British researchers warned in March that health systems will likely see an “influx of patients with psychiatric and cognitive problems who were otherwise healthy prior to COVID-19.” They urged doctors to consider detailed cognitive evaluations for anyone reporting new neurological symptoms after infection with SARS-CoV-2.

In the meantime, the Alzheimer’s Association has formed an international consortium to study the long-term effects of COVID-19 on the brain.

“These new data point to disturbing trends showing COVID-19 infections leading to lasting cognitive impairment and even Alzheimer’s symptoms,” stated Heather Snyder of the Alzheimer’s Association. “It is imperative that we continue to study what this virus is doing to our bodies and brains.”

Source: Duong D. Even mild COVID-19 may have long-term brain impacts. CMAJ. 2021 Aug 30;193(34):E1360-E1361. doi: 10.1503/cmaj.1095958. PMID: 34462298; PMCID: PMC8432319.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432319/ (Full text)

Neurovascular injury with complement activation and inflammation in COVID-19

Abstract:

The underlying mechanisms by which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to acute and long-term neurological manifestations remains obscure. We aimed to characterize the neuropathological changes in patients with coronavirus disease 2019 and determine the underlying pathophysiological mechanisms. In this autopsy study of the brain, we characterized the vascular pathology, the neuroinflammatory changes and cellular and humoral immune responses by immunohistochemistry.

All patients died during the first wave of the pandemic from March to July 2020. All patients were adults who died after a short duration of the infection, some had died suddenly with minimal respiratory involvement. Infection with SARS-CoV-2 was confirmed on ante-mortem or post-mortem testing. Descriptive analysis of the pathological changes and quantitative analyses of the infiltrates and vascular changes were performed.

All patients had multifocal vascular damage as determined by leakage of serum proteins into the brain parenchyma. This was accompanied by widespread endothelial cell activation. Platelet aggregates and microthrombi were found adherent to the endothelial cells along vascular lumina. Immune complexes with activation of the classical complement pathway were found on the endothelial cells and platelets. Perivascular infiltrates consisted of predominantly macrophages and some CD8+ T cells. Only rare CD4+ T cells and CD20+ B cells were present. Astrogliosis was also prominent in the perivascular regions. Microglial nodules were predominant in the hindbrain, which were associated with focal neuronal loss and neuronophagia.

Antibody-mediated cytotoxicity directed against the endothelial cells is the most likely initiating event that leads to vascular leakage, platelet aggregation, neuroinflammation and neuronal injury. Therapeutic modalities directed against immune complexes should be considered.

Source: Lee MH, Perl DP, Steiner J, Pasternack N, Li W, Maric D, Safavi F, Horkayne-Szakaly I, Jones R, Stram MN, Moncur JT, Hefti M, Folkerth RD, Nath A. Neurovascular injury with complement activation and inflammation in COVID-19. Brain. 2022 Jul 5:awac151. doi: 10.1093/brain/awac151. Epub ahead of print. PMID: 35788639; PMCID: PMC9278212. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9278212/ (Full text)

Mild respiratory SARS-CoV-2 infection can cause multi-lineage cellular dysregulation and myelin loss in the brain

Abstract:

Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection.

Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection – without neuroinvasion – and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function.

Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.

Source: Fernández-Castañeda A, Lu P, Geraghty AC, Song E, Lee MH, Wood J, Yalçın B, Taylor KR, Dutton S, Acosta-Alvarez L, Ni L, Contreras-Esquivel D, Gehlhausen JR, Klein J, Lucas C, Mao T, Silva J, Peña-Hernández MA, Tabachnikova A, Takahashi T, Tabacof L, Tosto-Mancuso J, Breyman E, Kontorovich A, McCarthy D, Quezado M, Hefti M, Perl D, Folkerth R, Putrino D, Nath A, Iwasaki A, Monje M. Mild respiratory SARS-CoV-2 infection can cause multi-lineage cellular dysregulation and myelin loss in the brain. bioRxiv [Preprint]. 2022 Jan 10:2022.01.07.475453. doi: 10.1101/2022.01.07.475453. PMID: 35043113; PMCID: PMC8764721.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8764721/ (Full text)

Animal Models for Neuroinflammation and Potential Treatment Methods

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown etiology and without effective treatment options. The onset of ME/CFS is often associated with neuroinflammation following bacterial or viral infection.

A positron emission tomography imaging study revealed that the degree of neuroinflammation was correlated with the severity of several symptoms in patients with ME/CFS. In animal studies, lipopolysaccharide- and polyinosinic-polycytidylic acid-induced models are thought to mimic the pathological features of ME/CFS and provoke neuroinflammation, characterized by increased levels of proinflammatory cytokines and activation of microglia.

In this review, we described the anti-inflammatory effects of three compounds on neuroinflammatory responses utilizing animal models. The findings of the included studies suggest that anti-inflammatory substances may be used as effective therapies to ameliorate disease symptoms in patients with ME/CFS.

Source: Tamura Y, Yamato M, Kataoka Y. Animal Models for Neuroinflammation and Potential Treatment Methods. Front Neurol. 2022 Jun 27;13:890217. doi: 10.3389/fneur.2022.890217. PMID: 35832182; PMCID: PMC9271866. https://pubmed.ncbi.nlm.nih.gov/35832182/  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9271866/ (Full study)

Could the kynurenine pathway be the key missing piece of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) complex puzzle?

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and debilitating disease with a substantial social and economic impact on individuals and their community. Despite its importance and deteriorating impact, progresses in diagnosis and treatment of ME/CFS is limited. This is due to the unclear pathophysiology of the disease and consequently lack of prognostic biomarkers.

To investigate pathophysiology of ME/CFS, several potential pathologic hallmarks have been investigated; however, these studies have failed to report a consistent result. These failures in introducing the underlying reason for ME/CFS have stimulated considering other possible contributing mechanisms such as tryptophan (TRP) metabolism and in particular kynurenine pathway (KP).

KP plays a central role in cellular energy production through the production of nicotinamide adenine dinucleotide (NADH). In addition, this pathway has been shown to mediate immune response and neuroinflammation through its metabolites. This review, we will discuss the pathology and management of ME/CFS and provide evidence pertaining KP abnormalities and symptoms that are classic characteristics of ME/CFS. Targeting the KP regulation may provide innovative approaches to the management of ME/CFS.

Source: Kavyani B, Lidbury BA, Schloeffel R, Fisher PR, Missailidis D, Annesley SJ, Dehhaghi M, Heng B, Guillemin GJ. Could the kynurenine pathway be the key missing piece of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) complex puzzle? Cell Mol Life Sci. 2022 Jul 11;79(8):412. doi: 10.1007/s00018-022-04380-5. PMID: 35821534. https://link.springer.com/article/10.1007/s00018-022-04380-5  (Full text)

Rapid improvement in severe long COVID following perispinal etanercept

Abstract:

Background: This study aimed to describe the neurological improvements in a patient with severe long COVID brain dysfunction following perispinal etanercept administration. Perispinal administration of etanercept, a novel method designed to enhance its brain delivery via carriage in the cerebrospinal venous system, has previously been shown to reduce chronic neurological dysfunction after stroke. Etanercept is a recombinant biologic that is capable of ameliorating two components of neuroinflammation: microglial activation and the excess bioactivity of tumor necrosis factor (TNF), a proinflammatory cytokine that is a key neuromodulator in the brain. Optimal synaptic and brain network function require physiological levels of TNF. Neuroinflammation, including brain microglial activation and excess central TNF, can be a consequence of stroke or peripheral infection, including infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19.

Methods: Standardized, validated measures, including the Montreal Cognitive Assessment, Beck Depression Index-II (BDI-II), Fatigue Assessment Scale, Controlled Oral Word Association Test, Trail Making Tests, Timed Finger-to-Nose Test, 20 meter Self-Paced Walk Test, 5 Times Sit-to-Stand Test and Grip Strength measured with a Jamar Dynamometer were used to quantitate changes in cognition, depression, fatigue and neurological function after a single 25mg perispinal etanercept dose in a patient with severe long COVID of 12 months duration.

Results: Following perispinal etanercept administration there was immediate neurological improvement. At 24 hours there were remarkable reductions in chronic post-COVID-19 fatigue and depression, and significant measureable improvements in cognition, executive function, phonemic verbal fluency, balance, gait, upper limb coordination and grip strength. Cognition, depression and fatigue were examined at 29 days; each remained substantially improved.

Conclusion: Perispinal etanercept is a promising treatment for the chronic neurologic dysfunction that may persist after resolution of acute COVID-19, including chronic cognitive dysfunction, fatigue, and depression. These results suggest that long COVID brain neuroinflammation is a potentially reversible pathology and viable treatment target. In view of the increasing unmet medical need, clinical trials of perispinal etanercept for long COVID are urgently necessary. The robust results of the present case suggest that perispinal etanercept clinical trials studying long COVID populations with severe fatigue, depression and cognitive dysfunction may have improved ability to detect a treatment effect. Positron emission tomographic methods that image brain microglial activation and measurements of cerebrospinal fluid proinflammatory cytokines may be useful for patient selection and correlation with treatment effects, as well as provide insight into the underlying pathophysiology.

Source: Tobinick E, Spengler RN, Ignatowski TA, Wassel M, Laborde S. Rapid improvement in severe long COVID following perispinal etanercept. Curr Med Res Opin. 2022 Jul 6:1-23. doi: 10.1080/03007995.2022.2096351. Epub ahead of print. PMID: 35791687.  https://pubmed.ncbi.nlm.nih.gov/35791687/

Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation?

Abstract:

As inflammation in the brain contributes to several neurological and psychiatric diseases, the cause of neuroinflammation is being widely studied. The causes of neuroinflammation can be roughly divided into the following domains: viral infection, autoimmune disease, inflammation from peripheral organs, mental stress, metabolic disorders, and lifestyle. In particular, the effects of neuroinflammation caused by inflammation of peripheral organs have yet unclear mechanisms.

Many diseases, such as gastrointestinal inflammation, chronic obstructive pulmonary disease, rheumatoid arthritis, dermatitis, chronic fatigue syndrome, or myalgic encephalomyelitis (CFS/ME), trigger neuroinflammation through several pathways. The mechanisms of action for peripheral inflammation-induced neuroinflammation include disruption of the blood-brain barrier, activation of glial cells associated with systemic immune activation, and effects on autonomic nerves via the organ-brain axis. In this review, we consider previous studies on the relationship between systemic inflammation and neuroinflammation, focusing on the brain regions susceptible to inflammation.

Source: Sun Y, Koyama Y, Shimada S. Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation? Front Aging Neurosci. 2022 Jun 16;14:903455. doi: 10.3389/fnagi.2022.903455. PMID: 35783147; PMCID: PMC9244793. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9244793/ (Full text)

Broken Connections: The Evidence for Neuroglial Failure in ME/CFS

Abstract:

In spite of decades of research, the pathobiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is still poorly understood. Several pathomechanisms have been identified, yet, it remains unclear how they are related and which of them may be upstream or downstream.

In this paper, we present a theoretical strategy that may help clarify the causal chain of pathophysiological events in ME/CFS. We propose to focus on the common final histological pathway of ME/CFS and suggest to ask: Which cellular compartment may explain the pathological processes and clinical manifestations observed in ME/CFS? Any functional unit consistently identified through this search may then be a plausible candidate for further exploration.

For this “histological” approach we have compiled a list of 22 undisputed clinical and pathophysiological features of ME/CFS that need to be plausibly and most directly explained by the dysfunctional cellular unit in question. For each feature we have searched the literature for pathophysiological explanations and analyzed if they may point to the same functional cellular unit. Through this search we have identified the CNS neuroglia – microglia and astroglia – as the one functional unit in the human body which may best explain all and any of the clinical and pathological features, dysfunctions and observations described for ME/CFS.

While this points to neuroinflammation as the central hub in ME/CFS, it also points to a novel understanding of the neuroimmune basis of ME/CFS. After all, the neuroglial cells are now understood as the functional matrix of the human brain connectome which operates beyond and above specific brain centers, receptor units or neurotransmitter systems and integrates innate immune functions with CNS regulatory functions pertaining to autonomous regulation, cellular metabolism and the stress response.

Source: Renz-Polster, H. (2021, August 3). Broken Connections: The Evidence for Neuroglial Failure in ME/CFS. https://doi.org/10.31219/osf.io/ef3n4 https://osf.io/ef3n4/ (Full text)

Molecular Mechanisms of Neuroinflammation in ME/CFS and Long COVID to Sustain Disease and Promote Relapses

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disease now well-documented as having arisen commonly from a viral infection, but also from other external stressors, like exposure to agricultural chemicals, other types of infection, surgery, or other severe stress events. Research has shown these events produce a systemic molecular inflammatory response and chronic immune activation and dysregulation. What has been more difficult to establish is the hierarchy of the physiological responses that give rise to the myriad of symptoms that ME/CFS patients experience, and why they do not resolve and are generally life-long.

The severity of the symptoms frequently fluctuates through relapse recovery periods, with brain-centered symptoms of neuroinflammation, loss of homeostatic control, “brain fog” affecting cognitive ability, lack of refreshing sleep, and poor response to even small stresses. How these brain effects develop with ME/CFS from the initiating external effector, whether virus or other cause, is poorly understood and that is what our paper aims to address.

We propose the hypothesis that following the initial stressor event, the subsequent systemic pathology moves to the brain via neurovascular pathways or through a dysfunctional blood-brain barrier (BBB), resulting in chronic neuroinflammation and leading to a sustained illness with chronic relapse recovery cycles. Signaling through recognized pathways from the brain back to body physiology is likely part of the process by which the illness cycle in the peripheral system is sustained and why healing does not occur. By contrast, Long COVID (Post-COVID-19 condition) is a very recent ME/CFS-like illness arising from the single pandemic virus, SARS-CoV-2.

We believe the ME/CFS-like ongoing effects of Long COVID are arising by very similar mechanisms involving neuroinflammation, but likely with some unique signaling, resulting from the pathology of the initial SARS-CoV-2 infection. The fact that there are very similar symptoms in both ongoing diseases, despite the diversity in the nature of the initial stressors, supports the concept of a similar dysfunctional CNS component common to both.

Source: Tate W, Walker M, Sweetman E, Helliwell A, Peppercorn K, Edgar C, Blair A, Chatterjee A. Molecular Mechanisms of Neuroinflammation in ME/CFS and Long COVID to Sustain Disease and Promote Relapses. Front Neurol. 2022 May 25;13:877772. doi: 10.3389/fneur.2022.877772. PMID: 35693009; PMCID: PMC9174654.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9174654/ (Full text)