Tag: endothelial dysfunction

Vascular “Long COVID”: A New Vessel Disease?

Abstract:

Vascular sequelae following (SARS-CoV-2 coronavirus disease) (COVID)-19 infection are considered as “Long Covid (LC)” disease, when occurring 12 weeks after the original infection. The paucity of specific data can be obviated by translating pathophysiological elements from the original Severe Acute Respiratory Syndrome-Corona Virus (SARS-CoV-2) infection (In a microcirculatory system, a first “endotheliitis,” is often followed by production of “Neutrophil Extracellular Trap,” and can evolve into a more complex leukocytoklastic-like and hyperimmune vasculitis. In medium/large-sized vessels, this corresponds to endothelial dysfunction, leading to an accelerated progression of pre-existing atherosclerotic plaques through an increased deposition of platelets, circulating inflammatory cells and proteins. Associated dysregulated immune and pro-coagulant conditions can directly cause thrombo-embolic arterial or venous complications. In order to implement appropriate treatment, physicians need to consider vascular pathologies observed after SARS-Cov-2 infections as possible “LC” disease.

Source: Zanini G, Selleri V, Roncati L, Coppi F, Nasi M, Farinetti A, Manenti A, Pinti M, Mattioli AV. Vascular “Long COVID”: A New Vessel Disease? Angiology. 2023 Jan 18:33197231153204. doi: 10.1177/00033197231153204. Epub ahead of print. PMID: 36652923. https://pubmed.ncbi.nlm.nih.gov/36652923/

Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies

Abstract:

The fight against coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is still raging. However, the pathophysiology of acute and post-acute manifestations of COVID-19 (long COVID-19) is understudied. Endothelial cells are sentinels lining the innermost layer of blood vessel that gatekeep micro- and macro-vascular health by sensing pathogen/danger signals and secreting vasoactive molecules. SARS-CoV-2 infection primarily affects the pulmonary system, but accumulating evidence suggests that it also affects the pan-vasculature in the extrapulmonary systems by directly (via virus infection) or indirectly (via cytokine storm), causing endothelial dysfunction (endotheliitis, endothelialitis and endotheliopathy) and multi-organ injury.

Mounting evidence suggests that SARS-CoV-2 infection leads to multiple instances of endothelial dysfunction, including reduced nitric oxide (NO) bioavailability, oxidative stress, endothelial injury, glycocalyx/barrier disruption, hyperpermeability, inflammation/leukocyte adhesion, senescence, endothelial-to-mesenchymal transition (EndoMT), hypercoagulability, thrombosis and many others. Thus, COVID-19 is deemed as a (micro)vascular and endothelial disease. Of translational relevance, several candidate drugs which are endothelial protective have been shown to improve clinical manifestations of COVID-19 patients.

The purpose of this review is to provide a latest summary of biomarkers associated with endothelial cell activation in COVID-19 and offer mechanistic insights into the molecular basis of endothelial activation/dysfunction in macro- and micro-vasculature of COVID-19 patients. We envisage further development of cellular models and suitable animal models mimicking endothelial dysfunction aspect of COVID-19 being able to accelerate the discovery of new drugs targeting endothelial dysfunction in pan-vasculature from COVID-19 patients.

Source: Xu, Sw., Ilyas, I. & Weng, Jp. Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies. Acta Pharmacol Sin (2022). https://doi.org/10.1038/s41401-022-00998-0 https://www.nature.com/articles/s41401-022-00998-0 (Full text)

Increased levels of inflammatory molecules in blood of Long COVID patients point to thrombotic endotheliitis

Abstract:

The prevailing hypotheses for the persistent symptoms of Long COVID have been narrowed down to immune dysregulation and autoantibodies, widespread organ damage, viral persistence, and fibrinaloid microclots (entrapping numerous inflammatory molecules) together with platelet hyperactivation. Here we demonstrate significantly increased concentrations of Von Willebrand Factor, platelet factor 4, serum amyloid A, alpha-2-antiplasmin E-selectin, and platelet endothelial cell adhesion molecule-1, in the soluble part of the blood.

It was noteworthy that the mean level of alpha-2-antiplasmin exceeded the upper limit of the laboratory reference range in Long COVID patients, and the other 5 were significantly elevated in Long COVID patients as compared to the controls. This is alarming if we take into consideration that a significant amount of the total burden of these inflammatory molecules has previously been shown to be entrapped inside fibrinolysis-resistant microclots (thus decreasing the apparent level of the soluble molecules). We also determined that by individually adding E-selectin and PECAM-1 to healthy blood, these molecules may indeed be involved in protein-protein interactions with plasma proteins (contributing to microclot formation) and platelet hyperactivation. This investigation was performed as a laboratory model investigation and the final exposure concentration of these molecules was chosen to mimic concentrations found in Long COVID.

We conclude that presence of microclotting, together with relatively high levels of six inflammatory molecules known to be key drivers of endothelial and clotting pathology, points to thrombotic endotheliitis as a key pathological process in Long COVID. This has implications for the choice of appropriate therapeutic options in Long COVID.

Source: Simone Turner, Caitlin Naidoo, Thomas Usher, Arneaux Kruger, Chantelle Venter, Gert J Laubscher, M Asad Khan, Douglas B Kell, Etheresia Pretorius. Increased levels of inflammatory molecules in blood of Long COVID patients point to thrombotic endotheliitis. medRxiv 2022.10.13.22281055; doi: https://doi.org/10.1101/2022.10.13.22281055 (Full text available as PDF file)

Circadian skin temperature rhythm and dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the role of endothelin-1 in the vascular dysregulation

Abstract:

Purpose: There is accumulating evidence of autonomic dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS); however, little is known about its association with circadian rhythms and endothelial dysfunction. This study aimed to explore the relationship between autonomic responses using an orthostatic test, skin temperature circadian variations, and circulating endothelial biomarkers in ME/CFS.

Methods: Sixty-seven adult female ME/CFS patients and 48 matched healthy controls were enrolled. Demographic and clinical characteristics suggestive of autonomic disturbances were assessed using validated self-reported outcome measures. Postural changes in blood pressure [BP], heart rate [HR], and wrist temperature (WT) were recorded during the orthostatic test. Actigraphy during one week was used to determine the 24-hour profile of peripheral temperature and motor activity. Circulating endothelial biomarkers were also measured as indicators of endothelial functioning.

Results: ME/CFS patients showed higher BP and HR values than healthy controls at rest (p < 0.05 for both), and also higher amplitude of the circadian activity rhythm (p < 0.01). Circulating levels of endothelin-1 (ET-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly higher in ME/CFS (p < 0.05). In ME/CFS, ET-1 levels were associated with the stability and amplitude of the temperature rhythm, (p < 0.01), and also with the self-reported questionnaires (p < 0.001).

Conclusions: ME/CFS patients exhibited alterations in circadian rhythms and hemodynamic measures that are associated with endothelial dysfunction, supporting previous evidence of dysautonomia in ME/CFS. Future investigation in this area is needed to assess vascular tone abnormalities and dysautonomia which may provide therapeutic targets for ME/CFS.

Source: Trinitat Cambras, Maria Fernanda Zerón-Rugerio, Antoni Díez-Noguera et al. Circadian skin temperature rhythm and dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the role of endothelin-1 in the vascular dysregulation, 21 September 2022, PREPRINT (Version 1) available at Research Square https://doi.org/10.21203/rs.3.rs-2044838/v1 (Full text)

Targeting endothelial dysfunction and oxidative stress in Long-COVID

Comment:

We thank Dr. Hsu and Dr. Lai for their interest in our work on COVID-19 and Long-COVID.

We fully agree with them on the fact that several factors need to be pondered in order to evaluate the risk of developing Long-COVID , . However, we respectfully believe that these considerations are not pertinent to our study . Indeed, we designed the LINCOLN (l-Arginine and Vitamin C improves Long-COVID) survey to determine whether a supplementation combining l-Arginine (to improve endothelial function) and Vitamin C (to reduce oxidation) could have favorable effects in patients with Long-COVID . Thus, in our study we did not assess the risk of developing Long-COVID; in fact, as clearly specified in our article, all the enrolled patients had Long-COVID when the survey was administered. Nevertheless, potential differences in health conditions between the group that had received l-Arginine + Vitamin C and the group that had received the alternative treatment were ruled out by their family physicians. When comparing the two groups, we did not observe any significant difference in terms of age, sex, hospitalization due to COVID-19, and time from SARS-Cov-2 negativization. Moreover, bearing in mind the limitations that all surveys have, we had concluded our article stating that further dedicated interventional studies were warranted to endorse our findings.

Of note, we have previously conducted a randomized, double-blind, placebo-controlled, parallel-group, clinical trial testing the effects of l-Arginine oral supplementation in patients hospitalized for COVID-19, demonstrating that this treatment significantly decreases the length of hospitalization and reduces the respiratory support . Additionally, we have identified endothelial exosomes enriched in miR-24 as a reliable biomarker to predict cerebrovascular complications of COVID-19 , corroborating the fundamental role of endothelial dysfunction in the pathobiology of COVID-19 and its clinical sequelae .

Source: Trimarco V, Izzo R, Mone P, Trimarco B, Santulli G. Targeting endothelial dysfunction and oxidative stress in Long-COVID. Pharmacol Res. 2022 Sep 13;184:106451. doi: 10.1016/j.phrs.2022.106451. Epub ahead of print. PMID: 36108875; PMCID: PMC9467917. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9467917/ (Full text)

Prevalence of symptoms, comorbidities, fibrin amyloid microclots and platelet pathology in individuals with Long COVID/Post-Acute Sequelae of COVID-19 (PASC)

Abstract:

Background: Fibrin(ogen) amyloid microclots and platelet hyperactivation previously reported as a novel finding in South African patients with the coronavirus 2019 disease (COVID-19) and Long COVID/Post-Acute Sequelae of COVID-19 (PASC), might form a suitable set of foci for the clinical treatment of the symptoms of Long COVID/PASC. A Long COVID/PASC Registry was subsequently established as an online platform where patients can report Long COVID/PASC symptoms and previous comorbidities.

Methods: In this study, we report on the comorbidities and persistent symptoms, using data obtained from 845 South African Long COVID/PASC patients. By using a previously published scoring system for fibrin amyloid microclots and platelet pathology, we also analysed blood samples from 80 patients, and report the presence of significant fibrin amyloid microclots and platelet pathology in all cases.

Results: Hypertension, high cholesterol levels (dyslipidaemia), cardiovascular disease and type 2 diabetes mellitus (T2DM) were found to be the most important comorbidities. The gender balance (70% female) and the most commonly reported Long COVID/PASC symptoms (fatigue, brain fog, loss of concentration and forgetfulness, shortness of breath, as well as joint and muscle pains) were comparable to those reported elsewhere. These findings confirmed that our sample was not atypical. Microclot and platelet pathologies were associated with Long COVID/PASC symptoms that persisted after the recovery from acute COVID-19.

Conclusions: Fibrin amyloid microclots that block capillaries and inhibit the transport of O2 to tissues, accompanied by platelet hyperactivation, provide a ready explanation for the symptoms of Long COVID/PASC. Removal and reversal of these underlying endotheliopathies provide an important treatment option that urgently warrants controlled clinical studies to determine efficacy in patients with a diversity of comorbidities impacting on SARS-CoV-2 infection and COVID-19 severity. We suggest that our platelet and clotting grading system provides a simple and cost-effective diagnostic method for early detection of Long COVID/PASC as a major determinant of effective treatment, including those focusing on reducing clot burden and platelet hyperactivation.

Source: Pretorius E, Venter C, Laubscher GJ, Kotze MJ, Oladejo SO, Watson LR, Rajaratnam K, Watson BW, Kell DB. Prevalence of symptoms, comorbidities, fibrin amyloid microclots and platelet pathology in individuals with Long COVID/Post-Acute Sequelae of COVID-19 (PASC). Cardiovasc Diabetol. 2022 Aug 6;21(1):148. doi: 10.1186/s12933-022-01579-5. PMID: 35933347; PMCID: PMC9356426. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9356426/ (Full text)

Serum of Post-COVID-19 Syndrome patients with or without ME/CFS differentially affects endothelial cell function in vitro

Abstract:

A proportion of COVID-19 reconvalescent patients develop post-COVID-19 syndrome (PCS) including a subgroup fulfilling diagnostic criteria of Myalgic encephalomyelitis/Chronic Fatigue Syndrome (PCS/CFS). Recently, endothelial dysfunction (ED) has been demonstrated in these patients, but the mechanisms remain elusive. Therefore, we investigated the effects of patients’ sera on endothelia cells (ECs) in vitro.
PCS (n = 17), PCS/CFS (n = 13), and healthy controls (HC, n = 14) were screened for serum anti-endothelial cell autoantibodies (AECAs) and dysregulated cytokines. Serum-treated ECs were analysed for the induction of activation markers and the release of small molecules by flow cytometry. Moreover, the angiogenic potential of sera was measured in a tube formation assay.
While only marginal differences between patient groups were observed for serum cytokines, AECA binding to ECs was significantly increased in PCS/CFS patients. Surprisingly, PCS and PCS/CFS sera reduced surface levels of several EC activation markers. PCS sera enhanced the release of molecules associated with vascular remodelling and significantly promoted angiogenesis in vitro compared to the PCS/CFS and HC groups. Additionally, sera from both patient cohorts induced the release of molecules involved in inhibition of nitric oxide-mediated endothelial relaxation.
Overall, PCS and PCS/CFS patients′ sera differed in their AECA content and their functional effects on ECs, i.e., secretion profiles and angiogenic potential. We hypothesise a pro-angiogenic effect of PCS sera as a compensatory mechanism to ED which is absent in PCS/CFS patients.
Source: Flaskamp L, Roubal C, Uddin S, Sotzny F, Kedor C, Bauer S, Scheibenbogen C, Seifert M. Serum of Post-COVID-19 Syndrome Patients with or without ME/CFS Differentially Affects Endothelial Cell Function In Vitro. Cells. 2022; 11(15):2376. https://doi.org/10.3390/cells11152376  https://www.mdpi.com/2073-4409/11/15/2376/htm (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)

Effect of SARS-CoV-2 proteins on vascular permeability

Abstract:

Severe acute respiratory syndrome (SARS)-CoV-2 infection leads to severe disease associated with cytokine storm, vascular dysfunction, coagulation, and progressive lung damage. It affects several vital organs, seemingly through a pathological effect on endothelial cells. The SARS-CoV-2 genome encodes 29 proteins, whose contribution to the disease manifestations, and especially endothelial complications, is unknown.

We cloned and expressed 26 of these proteins in human cells and characterized the endothelial response to overexpression of each, individually. Whereas most proteins induced significant changes in endothelial permeability, nsp2, nsp5_c145a (catalytic dead mutant of nsp5), and nsp7 also reduced CD31, and increased von Willebrand factor expression and IL-6, suggesting endothelial dysfunction. Using propagation-based analysis of a protein-protein interaction (PPI) network, we predicted the endothelial proteins affected by the viral proteins that potentially mediate these effects. We further applied our PPI model to identify the role of each SARS-CoV-2 protein in other tissues affected by coronavirus disease (COVID-19).

While validating the PPI network model, we found that the tight junction (TJ) proteins cadherin-5, ZO-1, and β-catenin are affected by nsp2, nsp5_c145a, and nsp7 consistent with the model prediction. Overall, this work identifies the SARS-CoV-2 proteins that might be most detrimental in terms of endothelial dysfunction, thereby shedding light on vascular aspects of COVID-19.

Source: Rauti R, Shahoha M, Leichtmann-Bardoogo Y, Nasser R, Paz E, Tamir R, Miller V, Babich T, Shaked K, Ehrlich A, Ioannidis K, Nahmias Y, Sharan R, Ashery U, Maoz BM. Effect of SARS-CoV-2 proteins on vascular permeability. Elife. 2021 Oct 25;10:e69314. doi: 10.7554/eLife.69314. PMID: 34694226; PMCID: PMC8545399. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8545399/ (Full text)

Sulodexide Significantly Improves Endothelial Dysfunction and Alleviates Chest Pain and Palpitations in Patients With Long-COVID-19: Insights From TUN-EndCOV Study

Abstract:

Objective: Non-respiratory long-coronavirus disease 2019 (COVID-19) symptoms are mainly related to a long-lasting endothelial dysfunction and microcirculation impairment. We hypothesized that Sulodexide, a purified glycosaminoglycan mixture with a beneficial endothelial effect in arterial and venous peripheral diseases, may be effective in a subset of patients with long COVID-19.

Approach and results: We conducted a multicenter prospective quasi-experimental study. A total of 290 patients from the TUN-EndCOV study with long-COVID-19 symptoms and endothelial dysfunction were included. The endothelial function was clinically assessed using a post-occlusive reactive hyperemia protocol with finger thermal monitoring device. Endothelial quality index (EQI) was assessed at inclusion and at 21 days later. The study population was assigned to a sulodexide group (144 patients) or a no-medical treatment group (146 patients). Clinical characteristics were similar at inclusion in the two groups. Fatigue, shortness of breath, and chest pain were the most common symptoms, respectively, 54.5, 53.8, and 28.3%. At 21 days, the sulodexide group improved significantly better than the no-medical treatment group in chest pain (83.7 vs. 43.6%, p < 10-3), palpitations (85.2 vs. 52.9%, p = 0.009), and endothelial function [median delta-EQI 0.66 (0.6) vs. 0.18 (0.3); p < 10-3]. Endothelial function improvement was significantly correlated with chest pain and palpitations recovery (AUC, i.e., area under the curve = 0.66, CI [0.57- 0.75], p = 0.001 and AUC = 0.60, CI [0.51- 0.69], p = 0.03, respectively).

Conclusion: Sulodexide significantly improves long-lasting post-COVID-19 endothelial dysfunction and alleviates chest pain and palpitations.

Source: Charfeddine S, Ibnhadjamor H, Jdidi J, Torjmen S, Kraiem S, Bahloul A, Makni A, Kallel N, Moussa N, Boudaya M, Touil I, Ghrab A, Elghoul J, Meddeb Z, Thabet Y, Ben Salem K, Addad F, Bouslama K, Milouchi S, Hammami R, Abdessalem S, Abid L. Sulodexide Significantly Improves Endothelial Dysfunction and Alleviates Chest Pain and Palpitations in Patients With Long-COVID-19: Insights From TUN-EndCOV Study. Front Cardiovasc Med. 2022 May 12;9:866113. doi: 10.3389/fcvm.2022.866113. PMID: 35647070; PMCID: PMC9133483. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9133483/ (Full text)