Tag: microvascular dysfunction

Increased von Willebrand and Factor VIII plasma levels in gynecologic patients with Post-Acute-COVID-Sequela (PASC)/Long COVID

Highlights:

  • Growing evidence suggests that persistent microvascular inflammation, clumping/clotting of blood cells and thrombotic complications may be key causes of Long COVID.
  • Plasma levels of von Willebrand factor and Factor VIII were uniformly higher in all gynecologic patients with Long COVID vs controls without Long COVID.
  • Persistently elevated levels of Von Willebrand and Factor VIII may represent the results of lingering microvascular damage (i.e., spike-induced endotheliosis).

Abstract:

Up to 30 % of COVID-infected patients may develop post-acute sequelae of COVID-19 (PASC), also known as Long COVID (LC), a syndrome characterized by a variety of debilitating symptoms lasting for more than 3 months after the acute infection. While the pathophysiological mechanisms behind PASC/LC are not completely understood, growing evidence suggests that an important component of this syndrome may be related to persistent microvascular inflammation causing clumping/clotting of red blood cells and platelets and thrombotic complications.

We retrospectively evaluated the plasma levels of von Willebrand factor (VWF), Factor VIII and D-dimer in 10 gynecologic patients (60 % with an endometrial or ovarian cancer diagnosis) affected by PASC/LC vs 5 control patients (60 % harboring endometrial or ovarian tumors). We found elevated VWF and Factor VIII levels in all 10 PASC/LC patients (means of 254 % and 229 %, respectively) vs none of the 5 randomly selected cancer control patients (means of 108 % and 95 %, respectively), p = 0.0046 and p < 0.0001, respectively. In contrast, no significant difference was noted in the levels of D-dimer in PASC/LC.

Importantly, abnormally elevated VWF and Factor VIII levels were found to persist for at least 2 years in patients with Long COVID symptoms. VWF and Factor VIII but not D-dimer levels are significantly elevated in the plasma of PASC/LC cancer patients. Abnormally and persistently elevated VWF and Factor VIII levels may represent the results of persistent microvascular damage (i.e., spike-induced endotheliosis) and may be biomarkers of persistent inflammation in gynecologic patients with PASC/LC.

Source: Stefania Bellone, Eric R. Siegel, David E. Scheim, Alessandro D. Santin.Increased von Willebrand and Factor VIII plasma levels in gynecologic patients with Post-Acute-COVID-Sequela (PASC)/Long COVID. Gynecologic Oncology Reports, Volume 51, February 2024, 101324. https://www.sciencedirect.com/science/article/pii/S2352578924000031 (Full text)

Post-COVID exercise intolerance is associated with capillary alterations and immune dysregulations in skeletal muscles

Abstract:

The SARS-CoV-2 pandemic not only resulted in millions of acute infections worldwide, but also in many cases of post-infectious syndromes, colloquially referred to as “long COVID”. Due to the heterogeneous nature of symptoms and scarcity of available tissue samples, little is known about the underlying mechanisms.

We present an in-depth analysis of skeletal muscle biopsies obtained from eleven patients suffering from enduring fatigue and post-exertional malaise after an infection with SARS-CoV-2. Compared to two independent historical control cohorts, patients with post-COVID exertion intolerance had fewer capillaries, thicker capillary basement membranes and increased numbers of CD169+ macrophages. SARS-CoV-2 RNA could not be detected in the muscle tissues.

In addition, complement system related proteins were more abundant in the serum of patients with PCS, matching observations on the transcriptomic level in the muscle tissue. We hypothesize that the initial viral infection may have caused immune-mediated structural changes of the microvasculature, potentially explaining the exercise-dependent fatigue and muscle pain.

Source: Aschman, T., Wyler, E., Baum, O. et al. Post-COVID exercise intolerance is associated with capillary alterations and immune dysregulations in skeletal muscles. acta neuropathol commun 11, 193 (2023). https://doi.org/10.1186/s40478-023-01662-2 https://actaneurocomms.biomedcentral.com/articles/10.1186/s40478-023-01662-2 (Full text)

Long COVID and its cardiovascular consequences: What is known?

Abstract:

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused high morbidity and mortality and has been a source of substantial challenges for healthcare systems globally. Despite a full recovery, a significant proportion of patients demonstrate a broad spectrum of cardiovascular, pulmonary and neurological symptoms that are believed to be caused by long-term tissue damage and pathological inflammation, which play a vital role in disease development. Microvascular dysfunction also causes significant health problems.

This review aimed to critically appraise the current data on the long-term cardiovascular sequelae of coronavirus disease 2019 (COVID-19), with a primary focus on cardiovascular symptoms such as chest pain, fatigue, palpitations, and breathlessness, and more significant disease entities including myocarditis, pericarditis and postural tachycardia syndrome. Potential risk factors identified in recent studies that contribute towards the development of long COVID are also included alongside a summary of recent advances in diagnostics and putative treatment options.

Source: Składanek JA, Leśkiewicz M, Gumiężna K, Baruś P, Piasecki A, Klimczak-Tomaniak D, Sygitowicz G, Kochman J, Grabowski M, Tomaniak M. Long COVID and its cardiovascular consequences: What is known? Adv Clin Exp Med. 2023 Jun 30. doi: 10.17219/acem/167482. Epub ahead of print. PMID: 37386857. https://advances.umw.edu.pl/en/ahead-of-print/167482/ (Full text)

Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation

Abstract:

Background: Post-COVID-19 syndrome (PCS) is a lingering disease with ongoing symptoms such as fatigue and cognitive impairment resulting in a high impact on the daily life of patients. Understanding the pathophysiology of PCS is a public health priority, as it still poses a diagnostic and treatment challenge for physicians.

Methods: In this prospective observational cohort study, we analyzed the retinal microcirculation using Retinal Vessel Analysis (RVA) in a cohort of patients with PCS and compared it to an age- and gender-matched healthy cohort (n=41, matched out of n = 204).

Measurements and main results: PCS patients exhibit persistent endothelial dysfunction (ED), as indicated by significantly lower venular flicker-induced dilation (vmax; 3.42% ± 1.77% vs. 4.64 % ± 2.59%; p = 0.02), narrower central retinal artery equivalent (CRAE; 178.1 [167.5 – 190.2] vs. 189.1 [179.4 – 197.2], p = 0.01) and lower arteriolar-venular ratio (AVR; (0.84 [0.8 – 0.9] vs. 0.88 [0.8 – 0.9], p = 0.007). When combining AVR and vmax, predicted scores reached good ability to discriminate groups (area under the curve: 0.75). Higher PCS severity scores correlated with lower AVR (R= -0.37 p = 0.017). The association of microvascular changes with PCS severity were amplified in PCS patients exhibiting higher levels of inflammatory parameters.

Conclusion: Our results demonstrate that prolonged endothelial dysfunction is a hallmark of PCS, and impairments of the microcirculation seem to explain ongoing symptoms in patients. As potential therapies for PCS emerge, RVA parameters may become relevant as clinical biomarkers for diagnosis and therapy management.

Source: Timon Kuchler, Roman Günthner, Andrea Ribeiro et al. Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation, 22 May 2023, PREPRINT (Version 1) available at Research Square https://doi.org/10.21203/rs.3.rs-2952588/v1 (Full text)

Thrombo-inflammation in Long COVID – the elusive key to post-infection sequelae?

Abstract:

Long COVID is a public health emergency affecting millions of people worldwide, characterized by heterogenous symptoms across multiple organs systems. Here, we discuss the current evidence linking thrombo-inflammation to Post-acute sequelae of COVID-19 (PASC).

Studies have found persistence of vascular damage with increased circulating markers of endothelial dysfunction, coagulation abnormalities with increased thrombin generation capacity, and abnormalities in platelet counts in PASC. Neutrophil phenotype resembles acute COVID-19 with an increase in activation and NETosis. These insights are potentially linked by elevated platelet-neutrophil aggregate formation. This hypercoagulable state in turn can lead to microvascular thrombosis, evidenced by microclots and elevated D-Dimer in the circulation, as well as perfusion abnormalities in the lung and brain of Long COVID patients. Also, COVID-19 survivors suffer from an increased rate of arterial and venous thrombotic events.

We discuss three important, potentially intertwined hypotheses, that might contribute to thromboinflammation in Long COVID: Lasting structural changes, most prominently endothelial damage, caused during initial infection, a persistent viral reservoir, and immunopathology driven by a misguided immune system.

Lastly, we outline the necessity for large, well-characterized clinical cohorts and mechanistic studies to clarify the contribution of thromboinflammation to Long COVID.

Source: Nicolai L, Kaiser R, Stark K. Thrombo-inflammation in Long COVID – the elusive key to post-infection sequelae? J Thromb Haemost. 2023 May 11:S1538-7836(23)00400-2. doi: 10.1016/j.jtha.2023.04.039. Epub ahead of print. PMID: 37178769; PMCID: PMC10174338. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10174338/ (Full text)

Direct and indirect impact of SARS-CoV-2 on the brain

Abstract:

Although COVID-19 is mostly a pulmonary disease, it is now well accepted that it can cause a much broader spectrum of signs and symptoms and affect many other organs and tissue. From mild anosmia to severe ischemic stroke, the impact of SARS-CoV-2 on the central nervous system is still a great challenge to scientists and health care practitioners.

Besides the acute and severe neurological problems described, as encephalopathies, leptomeningitis, and stroke, after 2 years of pandemic, the chronic impact observed during long-COVID or the post-acute sequelae of COVID-19 (PASC) greatly intrigues scientists worldwide. Strikingly, even asymptomatic, and mild diseased patients may evolve with important neurological and psychiatric symptoms, as confusion, memory loss, cognitive decline, chronic fatigue, associated or not with anxiety and depression. Thus, the knowledge on the correlation between COVID-19 and the central nervous system is of great relevance.

In this sense, here we discuss some important mechanisms obtained from in vitro and in vivo investigation regarding how SARS-CoV-2 impacts the brain and its cells and function.

Source: Peron JPS. Direct and indirect impact of SARS-CoV-2 on the brain. Hum Genet. 2023 Apr 1:1–10. doi: 10.1007/s00439-023-02549-x. Epub ahead of print. PMID: 37004544; PMCID: PMC10066989. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10066989/ (Full text)

Post-COVID syndrome is associated with capillary alterations, macrophage infiltration and distinct transcriptomic signatures in skeletal muscles

Abstract:

The SARS-CoV-2 pandemic not only resulted in millions of acute infections worldwide, but also caused innumerable cases of post-infectious syndromes, colloquially referred to as “long COVID”. Due to the heterogeneous nature of symptoms and scarcity of available tissue samples, little is known about the underlying mechanisms. We present an in-depth analysis of skeletal muscle biopsies obtained from eleven patients suffering from enduring fatigue and post-exertional malaise after an infection with SARS-CoV-2.

Compared to two independent historical control cohorts, patients with post-COVID exertion intolerance had fewer capillaries, thicker capillary basement membranes and increased numbers of CD169+ macrophages. SARS-CoV-2 RNA could not be detected in the muscle tissues, but transcriptomic analysis revealed distinct gene signatures compared to the two control cohorts, indicating immune dysregulations and altered metabolic pathways.

We hypothesize that the initial viral infection may have caused immune-mediated structural changes of the microvasculature, potentially explaining the exercise-dependent fatigue and muscle pain.

Source: Tom Aschman, Emanuel Wyler, Oliver Baum, Andreas Hentschel, Franziska Legler, Corinna Preusse, Lil Meyer-Arndt, Ivana Büttnerova, Alexandra Förster, Derya Cengiz, Luiz Gustavo Teixeira Alves, Julia Schneider, Claudia Kedor, Rebecca Rust, Judith Bellmann-Strobl, Sanchin Aminaa, Peter Vajkoczy, Hans-Hilmar Goebel, Markus Landthaler, Victor Corman, Andreas Roos, Frank L. Heppner, Helena Radbruch, Friedemann Paul, Carmen Scheibenbogen, Werner Stenzel, Nora F. Dengler. Post-COVID syndrome is associated with capillary alterations, macrophage infiltration and distinct transcriptomic signatures in skeletal muscles. medRxiv 2023.02.15.23285584; doi: https://doi.org/10.1101/2023.02.15.23285584 https://www.medrxiv.org/content/10.1101/2023.02.15.23285584v1.full-text (Full text)

Long Covid and Neurodegenerative Disease

Abstract:

Brain fog with compromised ability to concentrate has been the most frequent Long Covid (LC) complaint. This is due to an increased TGF beta/IFN gamma with consequently increased bradykinin (BKN), especially in Caucasian females. Brain and lung blood vessels “leak.” This same ratio is increased in Alzheimer’s disease (AD), but decreased in Parkinson’s disease (PD), because CD4+ and CD8+ T cells are differentially affected by the invading associated viruses, e.g., SARS CoV2, HIV, ….

In Covid-19 CD147 receptors on immune cells are critical in generating the increased TGF beta/IFN gamma and those on endothelial cells, platelets, and erythrocytes are critical to the abnormal microvascular blood flow. ACE2 receptors on pneumocytes and enterocytes enable pulmonary and GI entry, initiating gut dysbiosis.

Epigenetics, methylation, magnesium, vitamin D, the B vitamins, and antioxidants suggest that these issues can be surmounted. Biochemical, physiologic, and epidemiologic data are analyzed to answer these questions. An LC model is presented and discussed in the context of the most recent research. Suggestions to avoid these and other worrisome concerns are included. Other topics discussed include estrogen, the gut microbiome, type 2 diabetes (T2D), and homocysteine.

Source: Chambers, P. Long Covid and Neurodegenerative Disease. Preprints 2023, 2023020027 (doi: 10.20944/preprints202302.0027.v1) https://www.preprints.org/manuscript/202302.0027/v1 (Full text available as PDF file)

 

Endothelial dysfunction in ME/CFS patients

Abstract:

Objective: A few earlier studies have found impaired endothelial function in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). The present study investigated large-vessel and small-vessel endothelial function in patients with ME/CFS.

Study design: The study was a substudy of the RituxME trial, a national, multicenter, randomized, double-blind, placebo-controlled phase III study on the effect of rituximab vs. placebo in ME/CFS patients in Norway. Flow-mediated dilation (FMD) and post-occlusive reactive hyperemia (PORH) was measured at baseline and after 18 months of treatment in 39 patients and compared with healthy controls. Other outcome measures were symptom severity and various physical function measures.

Results: ME/CFS patients had markedly reduced FMD compared to healthy controls at baseline (5.1% vs. 8.2%, p< 0.0001, adjusted for arterial diameter and sex), and significantly lower microvascular regulation measured by PORH than healthy controls (1354 PU vs. 2208 PU, p = 0.002). There were no differences between the treatment and placebo groups in symptom changes or vascular measures. As a group, the ME/CSF patients experienced a slight, but significant improvement in clinical symptoms after 18 months. PORH, but not FMD, was similarly improved (1360 to 1834 PU, p = 0.028). There was no significant correlation between FMD and PORH. There were non-significant tendencies towards associations between symptom severity/physical function measures and lower FMD and PORH, and a significant correlation between PORH and steps per 24 hours at baseline.

Conclusions: ME/CFS patients had reduced macro- and microvascular endothelial function, indicating that vascular homeostasis may play a role in the clinical presentation of this disease.

Source: Sandvik MK, Sørland K, Leirgul E, Rekeland IG, Stavland CS, Mella O, Fluge Ø. Endothelial dysfunction in ME/CFS patients. PLoS One. 2023 Feb 2;18(2):e0280942. doi: 10.1371/journal.pone.0280942. PMID: 36730360; PMCID: PMC9894436. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9894436/ (Full text)

Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect?

Abstract:

Following COVID-19 infection, a substantial proportion of patients suffer from persistent symptoms known as Long COVID. Among the main symptoms are fatigue, cognitive dysfunction, muscle weakness and orthostatic intolerance (OI). These symptoms also occur in myalgic encephalomyelitis/chronic fatigue (ME/CFS).
OI is highly prevalent in ME/CFS and develops early during or after acute COVID-19 infection. The causes for OI are unknown and autonomic dysfunction is hypothetically assumed to be the primary cause, presumably as a consequence of neuroinflammation. Here, we propose an alternative, primary vascular mechanism as the underlying cause of OI in Long COVID.
We assume that the capacitance vessel system, which plays a key role in physiologic orthostatic regulation, becomes dysfunctional due to a disturbance of the microvessels and the vasa vasorum, which supply large parts of the wall of those large vessels. We assume that the known microcirculatory disturbance found after COVID-19 infection, resulting from endothelial dysfunction, microthrombus formation and rheological disturbances of blood cells (altered deformability ), also affects the vasa vasorum to impair the function of the capacitance vessels.
In an attempt to compensate for the vascular deficit, sympathetic activity overshoots to further worsen OI, resulting in a vicious circle that maintains OI. The resulting orthostatic stress, in turn, plays a key role in autonomic dysfunction and the pathophysiology of ME/CFS.
Source: Wirth KJ, Löhn M. Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect? Medicina. 2022; 58(12):1807. https://doi.org/10.3390/medicina58121807 https://www.mdpi.com/1648-9144/58/12/1807 (Full text)