Tag: long covid pathophysiology

Systemic antibody responses against human microbiota flagellins are overrepresented in chronic fatigue syndrome patients

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with an unclear etiology and pathogenesis. Both an involvement of the immune system and gut microbiota dysbiosis have been implicated in its pathophysiology. However, potential interactions between adaptive immune responses and the microbiota in ME/CFS have been incompletely characterized. Here, we profiled antibody responses of patients with severe ME/CFS and healthy controls against microbiota and viral antigens represented as a phage-displayed 244,000 variant library.

Patients with severe ME/CFS exhibited distinct serum antibody epitope repertoires against flagellins of Lachnospiraceae bacteria. Training machine learning algorithms on this antibody-binding data demonstrated that immune responses against gut microbiota represent a unique layer of information beyond standard blood tests, providing improved molecular diagnostics for ME/CFS.

Together, our results point toward an involvement of the microbiota-immune axis in ME/CFS and lay the foundation for comparative studies with inflammatory bowel diseases and illnesses characterized by long-term fatigue symptoms, including post-COVID-19 syndrome.

Source: Vogl T, Kalka IN, Klompus S, Leviatan S, Weinberger A, Segal E. Systemic antibody responses against human microbiota flagellins are overrepresented in chronic fatigue syndrome patients. Sci Adv. 2022 Sep 23;8(38):eabq2422. doi: 10.1126/sciadv.abq2422. Epub 2022 Sep 23. PMID: 36149952. https://www.science.org/doi/10.1126/sciadv.abq2422 (Full text)

Understanding myalgic encephalomyelitis

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe condition characterized by post-exertional neuroimmune exhaustion (PENE) accompanied by neurological, immunological, gastrointestinal (GI), and mitochondrial disturbances (1). The global prevalence of ME/CFS is ∼1%, affecting 17 million to 24 million people (2). ME/CFS is heterogeneous not only in symptom presentation but also illness trajectories, which can be worsening, plateauing, improving, or relapsing-remitting. Approximately 25% of patients with ME/CFS are considered severe and are bound to their homes. Although the etiology of ME/CFS is elusive, a large proportion of patients (∼60%) report post-infectious onset, such as after Epstein-Barr virus infection (3). The recent emergence of a chronic post-infectious condition, called Long Covid, overlaps considerably with ME/CFS in immunological, mitochondrial, and neurological dysfunctions (4). These similarities have resulted in increased interest and acceptance of ME/CFS as a disease and may stimulate research, the development of a diagnostic test, and pharmacotherapeutic interventions in ME/CFS that may be applied to Long Covid.

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Source: Sonya Marshall-Gradisnik and Natalie Eaton-Fitch. Understanding myalgic encephalomyelitis. SCIENCE, 8 Sep 2022, Vol 377, Issue 6611, pp. 1150-1151, DOI: 10.1126/science.abo126 https://www.science.org/doi/10.1126/science.abo1261 (Full text)

Long-term cardiac pathology in individuals with mild initial COVID-19 illness

Abstract:

Cardiac symptoms are increasingly recognized as late complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in previously well individuals with mild initial illness, but the underlying pathophysiology leading to long-term cardiac symptoms remains unclear.

In this study, we conducted serial cardiac assessments in a selected population of individuals with Coronavirus Disease 2019 (COVID-19) with no previous cardiac disease or notable comorbidities by measuring blood biomarkers of heart injury or dysfunction and by performing magnetic resonance imaging. Baseline measurements from 346 individuals with COVID-19 (52% females) were obtained at a median of 109 days (interquartile range (IQR), 77–177 days) after infection, when 73% of participants reported cardiac symptoms, such as exertional dyspnea (62%), palpitations (28%), atypical chest pain (27%) and syncope (3%). Symptomatic individuals had higher heart rates and higher imaging values or contrast agent accumulation, denoting inflammatory cardiac involvement, compared to asymptomatic individuals. Structural heart disease or high levels of biomarkers of cardiac injury or dysfunction were rare in symptomatic individuals.

At follow-up (329 days (IQR, 274–383 days) after infection), 57% of participants had persistent cardiac symptoms. Diffuse myocardial edema was more pronounced in participants who remained symptomatic at follow-up as compared to those who improved. Female gender and diffuse myocardial involvement on baseline imaging independently predicted the presence of cardiac symptoms at follow-up. Ongoing inflammatory cardiac involvement may, at least in part, explain the lingering cardiac symptoms in previously well individuals with mild initial COVID-19 illness.

Source: Puntmann, V.O., Martin, S., Shchendrygina, A. et al. Long-term cardiac pathology in individuals with mild initial COVID-19 illness. Nat Med (2022). https://doi.org/10.1038/s41591-022-02000-0 https://www.nature.com/articles/s41591-022-02000-0 (Full text)

Lots of long COVID treatment leads, but few are proven

As the current crisis phase of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic winds down—and the world nervously awaits potentially dangerous new variants—research into the nature and treatment of so-called long coronavirus disease (COVID) is beginning to ramp up. The White House has promised funding and a federal research roadmap, and dedicated clinics have started cropping up at academic medical centers across the country.

But attempts to understand and treat long COVID have been underway almost since the pandemic began. For more than 2 years, clinicians have been coping—mostly on their own—with streams of patients complaining of persistent symptoms or mysterious new ones after a bout with COVID-19 had seemingly resolved ( 1 ). And collectively, doctors and researchers have already made headway toward identifying some of the mechanisms underlying the condition—formally known as post-acute sequelae of COVID (PASC).

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Source: Leah Shaffer. Lots of long COVID treatment leads, but few are proven. Vol. 119 | No. 36. https://www.pnas.org/doi/10.1073/pnas.2213524119 (Full text)

Post COVID syndrome: A novel challenge and threat to international health

Abstract:

The global pandemic caused by the SARS-CoV-2 virus has affected every continent worldwide. The novelty of this virus, its mutations and the rapid speed and unprecedented rate at which it has torn through the global community has in turn lead to an innate lack of knowledge and information about the actual disease caused and the severity of the complications associated with COVID-19.

The SARS-CoV-2 virus has been infecting individuals since 2019 and now as of 2022 has been circulating for just over 2 years within the global populous. As the number of cases have risen globally over this period (some of which having contracted the virus twice) further endeavours have been undertaken to better understand the pathogenesis and natural progression of the disease. A condition reported in some cases with extended bouts of sickness or symptoms following the initial infection with COVID was labelled “long COVID” towards the earlier phases of the pandemic (in the spring of 2020), but has only recently gained the global media and medical attention due to its affliction of more individuals on a global basis and has thus warranted further investigation.

Long COVID is described as a persistent, long-term state of poor health following an infection with COVID-19. The effect of Long COVID is multisystemic in nature with a wide array of signs and symptoms. The most commonly reported clinical features of long COVID are: headaches, myalgia, chest pain, rashes, abdominal pain, shortness of breath, palpitations, anosmia, persistent cough, brain fogs, forgetfulness, depression, insomnia, fatigue and anxiety. This research aims to explore the symptomatology, pathophysiology as well as the treatment and prevention of Long COVID.

Source: Banerjee I, Robinson J, Leclézio A, Sathian B, Banerjee I. Post COVID syndrome: A novel challenge and threat to international health. Nepal J Epidemiol. 2022 Jun 30;12(2):1215-1219. doi: 10.3126/nje.v12i2.46149. PMID: 35974973; PMCID: PMC9374107.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9374107/ (Full text)

Long-COVID neurological symptoms are associated with D-dimer levels in COVID-19 patients

Abstract:

Background: Coronavirus disease 2019 (COVID-19) is a disease designated as a global pandemic by the WHO that can manifest clinically as neurological disorders that can occur in the acute phase or after the acute phase (long COVID-19), such as headache, myalgia, anosmia, and cognitive impairment. These neurological disorders as symptoms of long COVID-19 are presumably caused by hypercoagulable conditions characterized by an increase in D-dimer level. This study aims to determine the correlation of long COVID-19 neurological symptoms with hypercoagulable conditions and the role of D-dimer as a biomarker of long COVID-19 neurological symptoms.

Methods: This was a cross-sectional study involving 31 patients with long COVID-19 symptoms. Admitted long COVID-19 cases with recorded D-dimer levels and definitive outcomes were included consecutively. Long COVID-19 neurological symptoms were collected. D-dimer level was measured using immunofluorescence assay and reported in fibrinogen equivalent units (ìg/mL). The correlation between D-dimer levels and neurological clinical manifestations was assessed by using ordinal regression analysis. The p-value of <0.05 was considered statistically significant.

Results: The mean age of the subjects was 38.81 ± 11.58 years and 18 (58.06%) were female. Long COVID neurological symptoms comprised myalgia, anosmia and cephalgia, and most subjects complained of myalgia (80.65%). On multivariable analysis, long-COVID-19 neurological symptoms were significantly correlated with D-dimer [odds ratio (OR) = 1.05; p=0.020].

Conclusion: The number of neurological long COVID symptoms were significantly correlated with level of D-Dimer. Ultimately, more clarity is needed on the neurological impact of COVID-19, its diagnosis, and its treatment.

Source: Mirawati, D. K., Budianto, P., Danuaji, R., Subandi, S., Ristinawati, I., & Prabaningtyas, H. R. (2022). Long-COVID neurological symptoms are associated with D-dimer levels in COVID-19 patients. Universa Medicina, 41(2), 169–175. https://doi.org/10.18051/UnivMed.2022.v41.169-175 https://univmed.org/ejurnal/index.php/medicina/article/view/1246

COVID-19 and Therapeutic Apheresis

Abstract:

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, is an unprecedented challenge for the global community. The pathogenesis of COVID-19, its complications and long term sequelae (so called Long/Post-COVID) include, in addition to the direct virus-induced tissues injury, multiple secondary processes, such as autoimmune response, impairment of microcirculation, and hyperinflammation. Similar pathological processes, but in the settings of neurological, cardiovascular, rheumatological, nephrological, and dermatological diseases can be successfully treated by powerful methods of Therapeutic Apheresis (TA).

We describe here the rationale and the initial attempts of TA treatment in severe cases of acute COVID-19. We next review the evidence for the role of autoimmunity, microcirculatory changes and inflammation in pathogenesis of Long/Post COVID and the rationale for targeting those pathogenic processes by different methods of TA. Finally, we discuss the impact of COVID-19 pandemic on patients, who undergo regular TA treatments due to their underlying chronic conditions, with the specific focus on the patients with inherited lipid diseases being treated at the Dresden University Apheresis Center.

Source: Tselmin S, Julius U, Jarzebska N, Rodionov R. COVID-19 and Therapeutic Apheresis. Horm Metab Res. 2022 Aug;54(8):571-577. doi: 10.1055/a-1864-9482. Epub 2022 Aug 9. PMID: 35944525.  https://pubmed.ncbi.nlm.nih.gov/35944525/

A Review of Respiratory Post-Acute Sequelae of COVID-19 (PASC) and the Potential Benefits of Pulmonary Rehabilitation

Abstract:

With the SARS-CoV-2 pandemic continuing into its third year, the number of patients who survive acute COVID-19 infection but go on to develop long-term symptoms is increasing daily. Those individuals who experience one or more of a variety of persistent symptoms post-COVID-19 are now diagnosed with the syndrome called post-acute sequelae of COVID-19 (PASC), often colloquially called “Long COVID.” This article discusses relevant research and current hypotheses regarding the pathophysiology and management of respiratory symptoms of PASC, in order to provide primary care physicians with context for management of this heterogeneous population. We focus on the growing body of research that supports the use of pulmonary rehabilitation for patients with PASC to improve symptoms and quality of life.

Source: Simon M, Simmons JE. A Review of Respiratory Post-Acute Sequelae of COVID-19 (PASC) and the Potential Benefits of Pulmonary Rehabilitation. R I Med J (2013). 2022 Sep 1;105(7):11-15. PMID: 35930484.  https://pubmed.ncbi.nlm.nih.gov/35930484/ http://rimed.org/rimedicaljournal/2022/09/2022-09-11-covid-simon.pdf (Full text available as PDF file)

Long COVID endotheliopathy: hypothesized mechanisms and potential therapeutic approaches

Abstract:

SARS-CoV-2–infected individuals may suffer a multi–organ system disorder known as “long COVID” or post-acute sequelae of SARS-CoV-2 infection (PASC). There are no standard treatments, the pathophysiology is unknown, and incidence varies by clinical phenotype.

Acute COVID-19 correlates with biomarkers of systemic inflammation, hypercoagulability, and comorbidities that are less prominent in PASC. Macrovessel thrombosis, a hallmark of acute COVID-19, is less frequent in PASC. Female sex at birth is associated with reduced risk for acute COVID-19 progression, but with increased risk of PASC. Persistent microvascular endotheliopathy associated with cryptic SARS-CoV-2 tissue reservoirs has been implicated in PASC pathology.

Autoantibodies, localized inflammation, and reactivation of latent pathogens may also be involved, potentially leading to microvascular thrombosis, as documented in multiple PASC tissues. Diagnostic assays illuminating possible therapeutic targets are discussed.

Source: Ahamed J, Laurence J. Long COVID endotheliopathy: hypothesized mechanisms and potential therapeutic approaches. J Clin Invest. 2022 Aug 1;132(15):e161167. doi: 10.1172/JCI161167. PMID: 35912863; PMCID: PMC9337829. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9337829/ (Full text)

Persistent capillary rarefication in long COVID syndrome

Abstract:

Background: Recent studies have highlighted Coronavirus disease 2019 (COVID-19) as a multisystemic vascular disease. Up to 60% of the patients suffer from long-term sequelae and persistent symptoms even 6 months after the initial infection.

Methods: This prospective, observational study included 58 participants, 27 of whom were long COVID patients with persistent symptoms > 12 weeks after recovery from PCR-confirmed SARS-CoV-2 infection. Fifteen healthy volunteers and a historical cohort of critically ill COVID-19 patients (n = 16) served as controls. All participants underwent sublingual videomicroscopy using sidestream dark field imaging. A newly developed version of Glycocheck™ software was used to quantify vascular density, perfused boundary region (PBR-an inverse variable of endothelial glycocalyx dimensions), red blood cell velocity (VRBC) and the microvascular health score (MVHS™) in sublingual microvessels with diameters 4-25 µm.

Measurements and main results: Although dimensions of the glycocalyx were comparable to those of healthy controls, a µm-precise analysis showed a significant decrease of vascular density, that exclusively affected very small capillaries (D5: – 45.16%; D6: – 35.60%; D7: – 22.79%). Plotting VRBC of capillaries and feed vessels showed that the number of capillaries perfused in long COVID patients was comparable to that of critically ill COVID-19 patients and did not respond adequately to local variations of tissue metabolic demand. MVHS was markedly reduced in the long COVID cohort (healthy 3.87 vs. long COVID 2.72 points; p = 0.002).

Conclusions: Our current data strongly suggest that COVID-19 leaves a persistent capillary rarefication even 18 months after infection. Whether, to what extent, and when the observed damage might be reversible remains unclear.

Source: Osiaevi I, Schulze A, Evers G, Harmening K, Vink H, Kümpers P, Mohr M, Rovas A. Persistent capillary rarefication in long COVID syndrome. Angiogenesis. 2022 Aug 11:1–9. doi: 10.1007/s10456-022-09850-9. Epub ahead of print. PMID: 35951203; PMCID: PMC9366128. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9366128/ (Full text)