From ‘mental fog’ to post-acute COVID-19 syndrome’s executive function alteration: Implications for clinical approach

Abstract:

A common symptom of the neuropsychiatric Post-Acute COVID-19 syndrome (neuro-PACS) is the so called ‘brain fog’. Patients describe the brain fog as problems with attention, memory and mental fatigue. Brain fog is experienced by 9-55% of people for months after having contracted SARS-CoV-2 virus. Several theories have been proposed to explain PACS’s brain fog, including a neuroinflammatory hypothesis, but the hypothesis remains to be proven. Here, we examined inflammatory and immunological blood profile in a cohort of patients with PACS to investigate the association between executive functions and blood inflammatory markers.

Executive function was assessed by the Trail Making Test (TMT) Part A and Part B, as well as the Barkley Deficits in Executive Functioning Scale (BDEFS), in 71 patients (36 men), average age of 40 years (range: 15-82, SD: 15.7). Impairment in executive functioning (BDEFS scores and TMT B scores) correlated with increased levels of Interleukin-6 (IL-6), fibrinogen and ferritin. Moreover, elevated levels of Il-6, fibrinogen, ferritin, tumor necrosis factor-alpha and C-reactive protein have been observed in PACS.

These findings demonstrate that PACS is characterized by the presence of an immuno-inflammatory process, which is associated with diminished executive functioning. Here, we argue in favour of a shift from the non-descriptive definition of ‘mental fog’ to a characterization of a subtype of PACS, associated with alteration in executive functioning. Implication for clinical settings and prevention are discussed.

Source: Pallanti S, Di Ponzio M, Gavazzi G, Gasic G, Besteher B, Heller C, Kikinis R, Makris N, Kikinis Z. From ‘mental fog’ to post-acute COVID-19 syndrome’s executive function alteration: Implications for clinical approach. J Psychiatr Res. 2023 Sep 30;167:10-15. doi: 10.1016/j.jpsychires.2023.09.017. Epub ahead of print. PMID: 37804756. https://pubmed.ncbi.nlm.nih.gov/37804756/

Monocytes subpopulations pattern in the acute respiratory syndrome coronavirus 2 virus infection and after long COVID-19

Abstract:

Introduction and objective: The present study sought to characterize the pattern of monocyte subpopulations in patients during the course of the infections caused by SARS-CoV-2 virus or who presented long COVID-19 syndrome compared to monocytes from patients with zika virus (Zika) or chikungunya virus (CHIKV).

Casuistry: Study with 89 peripheral blood samples from patients, who underwent hemogram and serology (IgG and IgM) for detection of Zika (Control Group 1, n = 18) or CHIKV (Control Group 2, n = 9), and from patients who underwent hemogram and reverse transcription polymerase chain reaction for detection of SARS-CoV-2 at the acute phase of the disease (Group 3, n = 19); and of patients who presented long COVID-19 syndrome (Group 4, n = 43). The monocyte and subpopulations counts were performed by flow cytometry.

Results: No significant difference was observed in the total number of monocytes between the groups. The classical (CD14++CD16) and intermediate (CD14+CD16+) monocytes counts were increased in patients with acute infection or with long COVID-19 syndrome. The monocytes subpopulations counts were lower in patients with infection Zika or CHIKV.

Conclusion: Increase in the monocyte subpopulations in patients with acute infection or with long COVID-19 syndrome may be an important finding of differentiated from the infection Zika or CHIKV.

Source: Pereira VIC, de Brito Junior LC, Falcão LFM, da Costa Vasconcelos PF, Quaresma JAS, Berg AVVD, Paixão APS, Ferreira RIS, Diks IBC. Monocytes subpopulations pattern in the acute respiratory syndrome coronavirus 2 virus infection and after long COVID-19. Int Immunopharmacol. 2023 Oct 5;124(Pt B):110994. doi: 10.1016/j.intimp.2023.110994. Epub ahead of print. PMID: 37804653. https://www.sciencedirect.com/science/article/abs/pii/S156757692301319X

Unraveling Post-COVID-19 Immune Dysregulation Using Machine Learning-based Immunophenotyping

Abstract:

The COVID-19 pandemic has left a significant mark on global healthcare, with many individuals experiencing lingering symptoms long after recovering from the acute phase of the disease, a condition often referred to as “long COVID.” This study delves into the intricate realm of immune dysregulation that ensues in 509 post-COVID-19 patients across multiple Iraqi regions during the years 2022 and 2023.

Utilizing advanced machine learning techniques for immunophenotyping, this research aims to shed light on the diverse immune dysregulation patterns present in long COVID patients. By analyzing a comprehensive dataset encompassing clinical, immunological, and demographic information, the study provides valuable insights into the complex interplay of immune responses following COVID-19 infection.

The findings reveal that long COVID is associated with a spectrum of immune dysregulation phenomena, including persistent inflammation, altered cytokine profiles, and abnormal immune cell subsets. These insights highlight the need for personalized interventions and tailored treatment strategies for individuals suffering from long COVID-19.

This research represents a significant step forward in our understanding of the post-COVID-19 immune landscape and opens new avenues for targeted therapies and clinical management of long COVID patients. As the world grapples with the long-term implications of the pandemic, these findings offer hope for improving the quality of life for those affected by this enigmatic condition.

Source: Maitham G. Yousif, Ghizal Fatima and Hector J. Castro et al. Unraveling Post-COVID-19 Immune Dysregulation Using Machine Learning-based Immunophenotyping. 2023. https://arxiv.org/ftp/arxiv/papers/2310/2310.01428.pdf (Full text)

How long is Long-COVID? Symptomatic improvement between 12 and 18 months in a prospective cohort study

Abstract:

Introduction COVID-19 infection can precede, in a proportion of patients, a prolonged syndrome including fatigue, exercise intolerance, mood and cognitive problems. This study aimed to describe the profile of fatigue-related, exercise-related, mood-related and cognitive-related outcomes in a COVID-19-exposed group compared with controls.

Methods 113 serving UK Armed Forces participants were followed up at 5, 12 (n=88) and 18 months (n=70) following COVID-19. At 18 months, 56 were in the COVID-19-exposed group with 14 matched controls. Exposed participants included hospitalised (n=25) and community (n=31) managed participants. 43 described at least one of the six most frequent symptoms at 5 months: fatigue, shortness of breath, chest pain, joint pain, exercise intolerance and anosmia. Participants completed a symptom checklist, patient-reported outcome measures (PROMs), the National Institute for Health cognitive battery and a 6-minute walk test (6MWT). PROMs included the Fatigue Assessment Scale (FAS), Generalised Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9) and Patient Checklist-5 (PCL-5) for post-traumatic stress.

Results At 5 and 12 months, exposed participants presented with higher PHQ-9, PCL-5 and FAS scores than controls (ES (effect size) ≥0.25, p≤0.04). By 12 months, GAD-7 was not significantly different to controls (ES <0.13, p=0.292). Remaining PROMs lost significant difference by 18 months (ES ≤0.11, p≥0.28). No significant differences in the cognitive scales were observed at any time point (F=1.96, p=0.167). At 5 and 12 months, exposed participants recorded significantly lower distances on the 6MWT (ηp2≥0.126, p<0.01). 6MWT distance lost significant difference by 18 months (ηp2<0.039, p>0.15).

Conclusions This prospective cohort-controlled study observed adverse outcomes in depression, post-traumatic stress, fatigue and submaximal exercise performance up to 12 months but improved by 18-month follow-up, in participants exposed to COVID-19 compared with a matched control group.

Source: Barker-Davies RM, O’Sullivan O, Holdsworth DA, et alHow long is Long-COVID? Symptomatic improvement between 12 and 18 months in a prospective cohort studyBMJ Mil Health Published Online First: 03 October 2023. doi: 10.1136/military-2023-002500 https://militaryhealth.bmj.com/content/early/2023/10/03/military-2023-002500.abstract (Full text available as PDF file)

Habitual short sleepers with pre-existing medical conditions are at higher risk of Long COVID

Abstract:

STUDY OBJECTIVES: Preliminary evidence suggests that the risk of Long COVID is higher among people with pre-existing medical conditions. Based on its proven adjuvant role in immunity, habitual sleep duration may alter the risk for developing Long COVID. The objective of this study was to determine whether the odds of Long COVID are higher amongst those with pre-existing medical conditions, and whether the strength of this association varies by habitual sleep duration.

METHODS: Using data from 13,461 respondents from 16 countries who participated in the 2021 survey based International COVID Sleep Study II (ICOSS II), we studied the associations between habitual sleep duration, pre-existing medical conditions, and Long COVID.

RESULTS: Of 2,508 individuals who had COVID-19, 61% reported at least one Long COVID symptom. Multivariable logistic regression analysis showed that the risk of having Long COVID was 1.8-fold higher for average-length sleepers (6-9h/night) with pre-existing medical conditions compared to those without pre-existing medical conditions [aOR 1.84 (1.18-2.90), P=0.008]. The risk of Long COVID was 3-fold higher for short sleepers with pre-existing medical conditions [aOR 2.95 (1.04-8.4), P=0.043] and not significantly higher for long sleepers with pre-existing conditions [aOR 2.11 (0.93-4.77), P=0.073] compared to average-length sleepers without pre-existing conditions.

CONCLUSIONS: Habitual short nighttime sleep duration exacerbated the risk of Long COVID in individuals with pre-existing conditions. Restoring nighttime sleep to average duration represents a potentially modifiable behavioral factor to lower the odds of Long COVID for at-risk patients.

Source: Linor Berezin, MD, et al. Habitual short sleepers with pre-existing medical conditions are at higher risk of Long COVID. Journal of Clinical Sleep Medicine, Articles in Advance. https://jcsm.aasm.org/doi/pdf/10.5664/jcsm.10818 (Full text)

Metabolic Fingerprinting for the Diagnosis of Clinically Similar Long COVID and Fibromyalgia Using a Portable FT-MIR Spectroscopic Combined with Chemometrics

Abstract:

Post Acute Sequelae of SARS-CoV-2 infection (PASC or Long COVID) is characterized by lingering symptomatology post-initial COVID-19 illness that is often debilitating. It is seen in up to 30–40% of individuals post-infection. Patients with Long COVID (LC) suffer from dysautonomia, malaise, fatigue, and pain, amongst a multitude of other symptoms.
Fibromyalgia (FM) is a chronic musculoskeletal pain disorder that often leads to functional disability and severe impairment of quality of life. LC and FM share several clinical features, including pain that often makes them indistinguishable. The aim of this study is to develop a metabolic fingerprinting approach using portable Fourier-transform mid-infrared (FT-MIR) spectroscopic techniques to diagnose clinically similar LC and FM.
Blood samples were obtained from LC (n = 50) and FM (n = 50) patients and stored on conventional bloodspot protein saver cards. A semi-permeable membrane filtration approach was used to extract the blood samples, and spectral data were collected using a portable FT-MIR spectrometer. Through the deconvolution analysis of the spectral data, a distinct spectral marker at 1565 cm−1 was identified based on a statistically significant analysis, only present in FM patients. This IR band has been linked to the presence of side chains of glutamate.
An OPLS-DA algorithm created using the spectral region 1500 to 1700 cm−1 enabled the classification of the spectra into their corresponding classes (Rcv > 0.96) with 100% accuracy and specificity. This high-throughput approach allows unique metabolic signatures associated with LC and FM to be identified, allowing these conditions to be distinguished and implemented for in-clinic diagnostics, which is crucial to guide future therapeutic approaches.
Source: Hackshaw KV, Yao S, Bao H, de Lamo Castellvi S, Aziz R, Nuguri SM, Yu L, Osuna-Diaz MM, Brode WM, Sebastian KR, et al. Metabolic Fingerprinting for the Diagnosis of Clinically Similar Long COVID and Fibromyalgia Using a Portable FT-MIR Spectroscopic Combined with Chemometrics. Biomedicines. 2023; 11(10):2704. https://doi.org/10.3390/biomedicines11102704 https://www.mdpi.com/2227-9059/11/10/2704 (Full text)

Pathophysiology and potential treatment of long COVID: A report of signal index cases and call for targeted research

Abstract:

Objective: Long COVID has afflicted tens of millions globally leaving many previously-healthy persons severely and indefinitely debilitated. The objective here was to report cases of complete, rapid remission of severe forms of long COVID following certain monoclonal antibody (MCA) infusions and review the corresponding pathophysiological implications.

Design: Case histories of the first three index events (among others) are presented. Unaware of others with similar remissions, each subject independently completed personal narratives and standardized surveys regarding demographics/occupation, past history, and the presence and respective severity grading of 33 signs/symptoms associated with long COVID, comparing the presence/severity of those symptoms during the pre-COVID, long-COVID, post-vaccination, and post-MCA phases.

Setting: Patient interviews, e-mails and telephone conversations.

Subjects: Three previously healthy, middle-aged, highly-functioning persons, two women and one man (ages 60, 43, and 63 years respectively) who, post-acute COVID-19 infection, developed chronic, unrelenting fatigue and cognitive impairment along with other severe, disabling symptoms. Each then independently reported incidental and unanticipated complete remissions within days of MCA treatment.

Interventions: The casirivimab/imdevimab cocktail.

Measurements and main results: Irrespective of sex, age, vaccination status, or illness duration (18, 8 and 5 months, respectively), each subject experienced the same complete remission of their persistent disabling disease within a week of MCA infusion. Each rapidly returned to normal health and previous lifestyles/occupations with normalized exercise tolerance, still sustained to date nearly two years later.

Conclusions: These index cases provide compelling clinical signals that MCA infusions may be capable of treating long COVID in certain cases, including those with severe debilitation. While the complete and sustained remissions observed here may only apply to long COVID resulting from pre-Delta variants and the specific MCA infused, the striking rapid and complete remissions observed in these cases also provide mechanistic implications for treating/managing other post-viral chronic conditions and long COVID from other variants.

Key points

  • Question: Considering that long COVID-19 has been devastating for many millions worldwide, what is the proposed pathophysiology and are there any effective treatments?
  • Findings: Previously-healthy middle-aged persons who had developed persistent debilitating post-acute SARS-CoV-2 sequelae, each experienced complete remission their symptoms within days of receiving a specific monoclonal anti-body infusion despite relative differences in sex, age, vaccination status, and long COVID duration.
  • Meaning: Certain monoclonal antibody infusions may be capable of reversing severe long COVID. Beyond providing an effective potential treatment for long COVID, these findings have mechanistic implications for treating other post-viral chronic conditions, including future long COVID variants.

Source: Kenneth A. Scheppke, Paul E. Pepe, Jonathan Jui, Remle P. Crowe, Eric K. Scheppke, Nancy G. Klimas, Aileen M. Marty. Pathophysiology and potential treatment of long COVID: A report of signal index cases and call for targeted research, The American Journal of Emergency Medicine, 2023. ISSN 0735-6757. https://doi.org/10.1016/j.ajem.2023.09.051. https://www.sciencedirect.com/science/article/abs/pii/S073567572300534X

Adipose-derived, autologous mesenchymal stem cell therapy for patients with post-COVID-19 syndrome: an intermediate-size expanded access program

Abstract:

Background: Evolving mutations of the novel coronavirus continue to fuel up the pandemic. The virus affects the human respiratory system along with other body systems, causing several sequelae in the survivors of the disease, presented as post-COVID-19 syndrome or long-COVID-19. This protocol utilized Hope Biosciences’ autologous, adipose-derived mesenchymal stem cells (HB-adMSCs) to evaluate safety and efficacy of HB-adMSC therapy to improve signs and symptoms associated with post-COVID-19 syndrome.

Methods: Ten eligible subjects with post-COVID-19 syndrome were enrolled in the program for a duration of 40 weeks who received 5 intravenous infusions of 2 × 108 autologous HB-adMSCs each at week 0, 2, 6, 10 and 14 with a follow-up at week 18 and end of the study at week 40. Safety assessments included incidence of adverse and serious adverse events along with the laboratory measures of hematologic, hepatic, and renal function. Efficacy was examined by quality-of-life assessments, fatigue assessments, Visual analog scale (VAS) of symptoms and monitoring of respiration and oxygen saturation rates.

Results: VAS scores and Fatigue Assessment scores (FAS) showed significant improvements post-treatment (P = 0.0039, ES = 0.91) compared to baseline. Respiration rates and oxygen saturation levels that were within the normal range at the baseline remained unchanged at the end of the study (EOS). Paired comparison between baseline and EOS for short-form-36 health survey questionnaire (SF-36) scores also showed improved quality-of-life with significant improvements in individual SF-36 evaluations. Mostly mild AEs were reported during the study period with no incidence of serious AEs. Also, no detrimental effects in laboratory values were seen.

Conclusions: The results of the expanded access program indicated that treatment with autologous HB-adMSCs resulted in significant improvements in the signs and symptoms associated with post-COVID-19 syndrome as assessed by VAS and FAS scores. Additionally, improvements in the patients’ quality-of-life as demonstrated using SF-36 scores that also showed significant improvements in individual scaled scores. Overall, administration of multiple infusions of autologous HB-adMSCs is safe and efficacious for improvements in the quality-of life of patients with post-COVID-19 syndrome.

Trial registration: Clinical trial registration number: NCT04798066. Registered on March 15, 2021. ( https://clinicaltrials.gov/ct2/show/NCT04798066?term=hope+biosciences&cond=Post-COVID-19+Syndrome&draw=2&rank=2 ).

Source: Vij R, Kim H, Park H, Cheng T, Lotfi D, Chang D. Adipose-derived, autologous mesenchymal stem cell therapy for patients with post-COVID-19 syndrome: an intermediate-size expanded access program. Stem Cell Res Ther. 2023 Oct 5;14(1):287. doi: 10.1186/s13287-023-03522-1. PMID: 37798650; PMCID: PMC10557203. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10557203/ (Full text)

Serotonin reduction in post-acute sequelae of viral infection

Highlights:

  • Long COVID is associated with reduced circulating serotonin levels
  • Serotonin depletion is driven by viral RNA-induced type I interferons (IFNs)
  • IFNs reduce serotonin through diminished tryptophan uptake and hypercoagulability
  • Peripheral serotonin deficiency impairs cognition via reduced vagal signaling

Summary:

Post-acute sequelae of COVID-19 (PASC, “Long COVID”) pose a significant global health challenge. The pathophysiology is unknown, and no effective treatments have been found to date. Several hypotheses have been formulated to explain the etiology of PASC, including viral persistence, chronic inflammation, hypercoagulability, and autonomic dysfunction. Here, we propose a mechanism that links all four hypotheses in a single pathway and provides actionable insights for therapeutic interventions. We find that PASC are associated with serotonin reduction.
Viral infection and type I interferon-driven inflammation reduce serotonin through three mechanisms: diminished intestinal absorption of the serotonin precursor tryptophan; platelet hyperactivation and thrombocytopenia, which impacts serotonin storage; and enhanced MAO-mediated serotonin turnover. Peripheral serotonin reduction, in turn, impedes the activity of the vagus nerve and thereby impairs hippocampal responses and memory. These findings provide a possible explanation for neurocognitive symptoms associated with viral persistence in Long COVID, which may extend to other post-viral syndromes.
Source: Wong et al., Serotonin reduction in post-acute sequelae of viral infection, Cell (2023), https://doi.org/
10.1016/j.cell.2023.09.013 https://www.cell.com/cell/fulltext/S0092-8674(23)01034-6 (Full text)

Accelerating discovery: A novel flow cytometric method for detecting fibrin(ogen) amyloid microclots using long COVID as a model

Abstract:

Long COVID has become a significant global health and economic burden, yet there are currently no established methods or diagnostic tools to identify which patients might benefit from specific treatments. One of the major pathophysiological factors contributing to Long COVID is the presence of hypercoagulability; this results in insoluble amyloid microclots that are resistant to fibrinolysis. Our previous research using fluorescence microscopy has demonstrated a significant amyloid microclot load in Long COVID patients. However, this approach lacked the elements of statistical robustness, objectivity, and rapid throughput.

In the current study, we have used imaging flow cytometry for the first time to show a significantly increased concentration and size of these microclots. We identified notable variations in size and fluorescence between microclots in Long COVID and those of controls even using a 20× objective. By combining cell imaging and the high-event-rate and full-sample analysis nature of a conventional flow cytometer, imaging flow cytometry can eliminate erroneous results and increase accuracy in gating and analysis beyond what pure quantitative measurements from conventional flow cytometry can provide.

Although imaging flow cytometry was used in our study, our results suggest that the signals indicating the presence of microclots should be easily detectable using a conventional flow cytometer. Flow cytometry is a more widely available technique than fluorescence microscopy and has been used in pathology laboratories for decades, rendering it a potentially more suitable and accessible method for detecting microclots in individuals suffering from Long COVID or conditions with similar pathology, such as myalgic encephalomyelitis.

Source: Turner S, Laubscher GJ, Khan MA, Kell DB, Pretorius E. Accelerating discovery: A novel flow cytometric method for detecting fibrin(ogen) amyloid microclots using long COVID as a model. Heliyon. 2023 Aug 29;9(9):e19605. doi: 10.1016/j.heliyon.2023.e19605. PMID: 37809592; PMCID: PMC10558872. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10558872/ (Full text)