Unveiling the Mysteries of Long COVID Syndrome: Exploring the Distinct Tissue and Organ Pathologies Linked to Prolonged COVID-19 Symptoms

Abstract:

The ongoing battle against the coronavirus disease 2019 (COVID-19) pandemic has encountered a complex aspect with the emergence of long COVID syndrome. There has been a growing prevalence of COVID-19-affected individuals experiencing persistent and diverse symptoms that extend beyond the initial infection phase. The phenomenon known as long COVID syndrome raises significant questions about the underlying mechanisms driving these enduring symptoms.

This comprehensive analysis explores the complex domain of long COVID syndrome with a view to shed light on the specific tissue and organ pathologies contributing to its intricate nature. This review aims to analyze the various clinical manifestations of this condition across different bodily systems and explore potential mechanisms such as viral persistence, immune dysregulation, autoimmunity, and molecular mimicry. The goal is to gain a better understanding of the intricate network of pathologies contributing to long COVID syndrome.

Understanding these distinct pathological indicators provides valuable insights into comprehending the complexities of long COVID and presents opportunities for developing more accurate diagnostic and therapeutic strategies, thereby improving the quality of patient care by effectively  addressing the ever-changing medical challenge in a more focused manner.

Source: Sapna F, Deepa F, Sakshi F, et al. (September 02, 2023) Unveiling the Mysteries of Long COVID Syndrome: Exploring the Distinct Tissue and Organ Pathologies Linked to Prolonged COVID-19 Symptoms. Cureus 15(9): e44588. DOI 10.7759/cureus.44588. https://assets.cureus.com/uploads/review_article/pdf/182615/20230903-23556-1g56qsl.pdf (Full text)

What Long COVID investigators can learn from four decades of ME/CFS research

Abstract:

Four decades of research in the field of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have yielded lessons that may be instructive for those devising criteria to better comprehend Post-Acute Sequelae of SARS CoV-2 Infection (PASC) and Long COVID.

For instance, substantial effort has been devoted to defining classification systems, operationalizing methods, and developing instruments with adequate reliability and validity in the ME/CFS field.

The current article provides guidelines for developing a case definition for Long COVID and discusses the significance of psychometric issues and criterion variance, including how to specify symptoms, develop thresholds, subtypes, and exclusionary conditions. ME/CFS research could enhance our knowledge of Long COVID pathophysiology, early diagnosis, prognosis, and the identification of effective treatments.

Source: Leonard A. Jason, Benjamin H. Natelson, Hector Bonilla, Zaki A. Sherif, Suzanne D. Vernon, Monica Verduzco Gutierrez, Lisa O’Brien, Emily Taylor. What Long COVID investigators can learn from four decades of ME/CFS research. Brain Behavior and Immunity Integrative, Volume 4, 2023, 100022. https://www.sciencedirect.com/science/article/pii/S2949834123000211 (Full text)

Efficiency of comprehensive rehabilitation of chronic fatigue syndrome due to coronavirus infections COVID-19

Abstract:

The aim of the study was to study the effectiveness of complex rehabilitation in patients with chronic fatigue syndrome caused by coronavirus infections.

In 120 patients with a confirmed diagnosis of SARS-CoV-2 (COVID-19) aged 20-58 years, post-COVID syndrome or chronic fatigue syndrome was detected, 52 men and 68 women. Patients had asthenic, cognitive, vegetative manifestations, sleep disorders, smell and taste disorders, anxiety and depression.

Patients received drug therapy: succinic acid preparations, brain metabolic drugs, stimulating antidepressants, sleeping pills – melatonin and B vitamins, among other things, received micropolarization of the head and translingualneurostimulation.

The results of treatment confirmed the effectiveness of the proposed conservative therapy. The neurological symptoms of post-COVID syndrome – chronic fatigue syndrome (CFS) were studied in 120 patients with a confirmed diagnosis of SARS-CoV-2 (COVID-19), aged 20-58 years.

Patients were examined according to the “Questionnaire for the detection of asthenia”, “Mini Mental State Assessment (MMSE)”, et.al. Sleep disorders were studied using the Epworth Sleepiness Scale, anxiety and depression were studied using the “Questionnaire for Determining Anxiety and Depression”.

The patients were divided into 2 groups: the main group (MG) – 69 patients and the control group (CG) – 51 patients. Patients with MG and CG received drug therapy: succinic acid preparations, brain metabolic drugs, stimulating antidepressants, sleeping pills – melatonin and B vitamins. And patients with MG, among other things, received micropolarization of the head and translingualneurostimulation.

Source: Z.I. Adambaev, I.A. Kilichev, A.B. Nurzhonov, N.Yu. Khudoyberganov, and M.R. Niyazmetov. Efficiency of comprehensive rehabilitation of chronic fatigue syndrome due to coronavirus infections COVID-19. BIO Web of Conferences 65, 05039 (2023) https://www.bio-conferences.org/articles/bioconf/abs/2023/10/bioconf_ebwff2023_05039/bioconf_ebwff2023_05039.html (Full text available as PDF file)

Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?

Abstract:

Both myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) and long COVID (LC) are characterized by similar immunological alterations, persistence of chronic viral infection, autoimmunity, chronic inflammatory state, viral reactivation, hypocortisolism, and microclot formation. They also present with similar symptoms such as asthenia, exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints. In addition, both pathologies present Epstein-Barr virus (EBV) reactivation, indicating the possibility of this virus being the link between both pathologies.

Therefore, we propose that latency and recurrent EBV reactivation could generate an acquired immunodeficiency syndrome in three steps: first, an acquired EBV immunodeficiency develops in individuals with “weak” EBV HLA-II haplotypes, which prevents the control of latency I cells. Second, ectopic lymphoid structures with EBV latency form in different tissues (including the CNS), promoting inflammatory responses and further impairment of cell-mediated immunity.

Finally, immune exhaustion occurs due to chronic exposure to viral antigens, with consolidation of the disease. In the case of LC, prior to the first step, there is the possibility of previous SARS-CoV-2 infection in individuals with “weak” HLA-II haplotypes against this virus and/or EBV.

Source: Ruiz-Pablos M, Paiva B, Zabaleta A. Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID? J Transl Med. 2023 Sep 17;21(1):633. doi: 10.1186/s12967-023-04515-7. PMID: 37718435. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-04515-7 (Full text)

Severity of neurological long-COVID symptoms correlates with increased level of autoantibodies targeting vasoregulatory and autonomic nervous system receptors

Abstract:

Background: The Long-COVID syndrome constitutes a plethora of persisting symptoms with neurological disorders being the most disabling ones. The pathogenesis of Long-COVID is currently under heavy scrutiny and existing data on the role of auto-immune reaction to G-protein coupled receptors (GPCR) are conflicting.

Methods: This monocentric, cross-sectional study included patients who suffered a mild to moderate SARS-CoV-2 infection up to 12 months prior to enrollment with (n = 72) or without (n = 58) Long-COVID diagnosis according to the German S1 guideline or with no known history of SARS-CoV-2 infection (n = 70). While autoantibodies towards the vasoregulation associated Adrenergic Receptor (ADR) B1 and B2 and the CNS and vasoregulation associated muscarinic acetylcholine receptor (CHR) M3 and M4 were measured by ELISA, neurological disorders were quantified by internationally standardized questionnaires.

Results: The prevalence and concentrations of evaluated autoantibodes were significantly higher in Long-COVID compared to the 2 other groups (p = 2.1*10−9) with a significantly higher number of patients with simultaneous detection of more than one autoantibody in Long-COVID group (p = 0.0419). Importantly, the overall inflammatory state was low in all 3 groups. ARB1 and ARB2 correlated negatively CERAD Trail Marking A and B (R ≤ −0.26, p ≤ 0.043), while CHRM3 correlated positively with Chadler Fatigue Scale (R = 0.37, p = 0.0087).

Conclusions: Concentrations of autoantibodies correlates to intensity of neurological disorders including psychomotor speed, visual search, attention, and fatigue.

Source: Felix S. Seibert, Ulrik Stervbo, Lea Wiemers, Sarah Skrzypczyk, Maximillian Hogeweg, Sebastian Bertram, Julia Kurek, Moritz Anft, Timm H. Westhoff, Nina Babel. Severity of neurological long-COVID symptoms correlates with increased level of autoantibodies targeting vasoregulatory and autonomic nervous system receptors. Autoimmunity Reviews,2023, 103445, ISSN 1568-9972. https://www.sciencedirect.com/science/article/abs/pii/S1568997223001799 (Full text)

The Potential Role of Hypothalamic Phospholipid Liposomes in the Supportive Therapy of Some Manifestations of Post-COVID-19 Condition: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Brain Fog

Abstract:

Post-COVID-19 condition (commonly known as Long COVID) is a heterogeneous clinical condition in which Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and brain fog stand out among the different clinical symptoms and syndromes. Cerebral metabolic alterations and neuroendocrine disorders seem to constitute an important part of the pathophysiology of Post-COVID-19 condition (PCC).

Given the substantial lack of specific drugs and effective therapeutic strategies, hypothalamic phospholipid liposomes, which have been on the market for several years as adjuvant therapy for cerebral metabolic alterations resulting from neuroendocrine disorders, might represent a potential option in an overall therapeutic strategy that aims to control PCC-associated symptoms and syndromes. Their pharmacological mechanisms and clinical effects strongly support their potential effectiveness in PCC. Our initial clinical experience seems to corroborate this rationale. Further controlled clinical research is warranted in order to verify this hypothesis.

Source: Menichetti F. The Potential Role of Hypothalamic Phospholipid Liposomes in the Supportive Therapy of Some Manifestations of Post-COVID-19 Condition: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Brain Fog. J Clin Med. 2023 Aug 23;12(17):5478. doi: 10.3390/jcm12175478. PMID: 37685544; PMCID: PMC10488182. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10488182/ (Full text)

SARS-CoV-2 reservoir in post-acute sequelae of COVID-19 (PASC)

Abstract:

Millions of people are suffering from Long COVID or post-acute sequelae of COVID-19 (PASC). Several biological factors have emerged as potential drivers of PASC pathology. Some individuals with PASC may not fully clear the coronavirus SARS-CoV-2 after acute infection. Instead, replicating virus and/or viral RNA-potentially capable of being translated to produce viral proteins-persist in tissue as a ‘reservoir’. This reservoir could modulate host immune responses or release viral proteins into the circulation.

Here we review studies that have identified SARS-CoV-2 RNA/protein or immune responses indicative of a SARS-CoV-2 reservoir in PASC samples. Mechanisms by which a SARS-CoV-2 reservoir may contribute to PASC pathology, including coagulation, microbiome and neuroimmune abnormalities, are delineated. We identify research priorities to guide the further study of a SARS-CoV-2 reservoir in PASC, with the goal that clinical trials of antivirals or other therapeutics with potential to clear a SARS-CoV-2 reservoir are accelerated.

Source: Proal AD, VanElzakker MB, Aleman S, Bach K, Boribong BP, Buggert M, Cherry S, Chertow DS, Davies HE, Dupont CL, Deeks SG, Eimer W, Ely EW, Fasano A, Freire M, Geng LN, Griffin DE, Henrich TJ, Iwasaki A, Izquierdo-Garcia D, Locci M, Mehandru S, Painter MM, Peluso MJ, Pretorius E, Price DA, Putrino D, Scheuermann RH, Tan GS, Tanzi RE, VanBrocklin HF, Yonker LM, Wherry EJ. SARS-CoV-2 reservoir in post-acute sequelae of COVID-19 (PASC). Nat Immunol. 2023 Sep 4. doi: 10.1038/s41590-023-01601-2. Epub ahead of print. PMID: 37667052. https://www.nature.com/articles/s41590-023-01601-2 (Full text)

Cardiovascular risk factors predict who should have echocardiographic evaluation in long COVID

Abstract:

Background: The need for echocardiograms among patients with long COVID is debatable. Our aim was to evaluate the prevalence of left ventricular (LV) dysfunction and identify predictors.
Methods: We conducted a cross-sectional study and included all consecutive patients enrolled in our post-COVID clinic. We included patients who had an echocardiogram and had no previous known heart disease. We defined LV dysfunction as a low ejection fraction or grade II to grade III diastolic dysfunction on an echocardiogram with evidence of elevated filling pressures. We calculated the prevalence of heart disease and predictors of heart disease using logistic regression.
Results: We included 217 post-COVID patients enrolled in the clinic. The prevalence of LV dysfunction is 24%;95% CI 18-30. Predictors of heart disease include older age and a previous history of hypertension and diabetes or having a intermediate or high ASCVD score. Patients with low ASCVD score did not have low ejection fraction on the screening echocardiograms.
Conclusion: Our study found a considerable number of patients with LV dysfunction. Older patients with cardiovascular risk factors are at risk of long COVID associated heart disease.
Source: Leonardo Tamariz, Mathew Ryan, George Marzouka R, et al. Cardiovascular risk factors predict who should have echocardiographic evaluation in long COVID. Authorea. August 23, 2023. https://www.authorea.com/doi/full/10.22541/au.169277562.22633945 (Full text available as download)

Long and Short-term Metformin Consumption as a Potential Therapy to Prevent Complications of COVID-19

Abstract:

Purpose: The aim of the study is to evaluate the effect of metformin in complication improvement of hospitalized patients with COVID-19.

Methods: This was a randomized clinical trial that involved 189 patients with confirmed COVID-19 infection. Patients in the intervention group received metformin-500 mg twice daily. Patients who received metformin before admission were excluded from the control group. Patients who were discharged before taking at least 2000 mg of metformin were excluded from the study. Primary outcomes were vital signs, need for ICU admission, need for intubation, and mortality.

Results: Data showed that patients with diabetes with previous metformin in their regimen had lower percentages of ICU admission and death in comparison with patients without diabetes (11.3% vs. 26.1% (P=0.014) and 4.9% vs. 23.9% (P≤0.001), respectively). Admission time characteristics were the same for both groups except for diabetes and hyperlipidemia, which were significantly different between the two groups. Observations of naproxen consumption on endpoints, duration of hospitalization, and the levels of spO2 did not show any significant differences between the intervention and the control group. The adjusted OR for intubation in the intervention group versus the control group was 0.21 [95% CI, 0.04-0.99 (P=0.047)].

Conclusion: In this trial, metformin consumption had no effect on mortality and ICU admission rates in non-diabetic patients. However, metformin improved COVID-19 complications in diabetic patients who had been receiving metformin prior to COVID-19 infection, and it significantly lowered the intubation rates.

Source: Shaseb E, Ghaffary S, Garjani A, Zoghi E, Maleki Dizaji N, Soltani S, Sarbakhsh P, Somi MH, Valizadeh P, Taghizadieh A, Faghihdinevari M, Varshochi M, Naghily B, Bayatmakoo Z, Saleh P, Taghizadeh S, Haghdoost M, Owaysi H, Ravanbakhsh Ghavghani F, Tarzamni MK, Moradi R, Javan Ali Azar F, Shabestari Khiabani S, Ghazanchaei A, Hamedani S, Hatefi S. Long and Short-term Metformin Consumption as a Potential Therapy to Prevent Complications of COVID-19. Adv Pharm Bull. 2023 Jul;13(3):621-626. doi: 10.34172/apb.2023.066. Epub 2022 Jul 2. PMID: 37646067; PMCID: PMC10460805. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10460805/ (Full text)

SARS-CoV-2-Specific Immune Responses in Patients With Postviral Syndrome After Suspected COVID-19

Abstract:

Background and objectives: Millions of Americans were exposed to SARS-CoV-2 early in the pandemic but could not get diagnosed with COVID-19 due to testing limitations. Many have developed a postviral syndrome (PVS) including neurologic manifestations similar to those with postacute sequelae of SARS-CoV-2 infection (Neuro-PASC). Owing to those circumstances, proof of SARS-CoV-2 infection was not required for evaluation at Northwestern Medicine’s Neuro COVID-19 clinic. We sought to investigate clinical and immunologic findings suggestive of SARS-CoV-2 exposure in patients with PVS.

Methods: We measured SARS-CoV-2-specific humoral and cell-mediated immune responses against Nucleocapsid and Spike proteins in 29 patients with PVS after suspected COVID-19, 32 confirmed age-matched/sex-matched Neuro-PASC (NP) patients, and 18 unexposed healthy controls. Neurologic symptoms and signs, comorbidities, quality of life, and cognitive testing data collected during clinic visits were studied retrospectively.

Results: Of 29 patients with PVS, 12 (41%) had detectable humoral or cellular immune responses consistent with prior exposure to SARS-CoV-2. Of 12 PVS responders (PVS+), 75% harbored anti-Nucleocapsid and 50% harbored anti-Spike responses. Patients with PVS+ had similar neurologic symptoms as patients with NP, but clinic evaluation occurred 5.3 months later from the time of symptom onset (10.7 vs 5.4 months; p = 0.0006). Patients with PVS+ and NP had similar subjective impairments in quality of life measures including cognitive function and fatigue. Patients with PVS+ had similar results in objective cognitive measures of processing speed, attention, and executive function and better results in working memory than patients with NP.

Discussion: Antibody and T-cell assays showed evidence of prior SARS-CoV-2 exposure in approximately 40% of the PVS group. Three-quarters of patients with PVS+ had detectable anti-Nucleocapsid and one-half anti-Spike responses, highlighting the importance of multitargeted COVID-19 immunologic evaluation and the limitations of commercially available diagnostic tests. Despite their persistent symptoms, lack of COVID-19 diagnosis likely delayed clinical care in patients with PVS. Our data suggest that millions of Americans presenting with PVS resembling Neuro-PASC were indeed exposed to SARS-CoV-2 at the beginning of the pandemic, and they deserve the same access to care and inclusion in research studies as patients with NP with confirmed COVID-19 diagnosis.

Source:Orban ZS, Visvabharathy L, Perez Giraldo GS, Jimenez M, Koralnik IJ. SARS-CoV-2-Specific Immune Responses in Patients With Postviral Syndrome After Suspected COVID-19. Neurol Neuroimmunol Neuroinflamm. 2023 Aug 23;10(6):e200159. doi: 10.1212/NXI.0000000000200159. PMID: 37612134; PMCID: PMC10448973. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10448973/ (Full text)