HIGH HEPARANASE LEVEL IN SURVIVORS OF COVID-19 - INDICATOR OF VASCULAR AND PULMONARY RECOVERY?

ABSTRACT: Background: Severe progression of coronavirus disease 2019 (COVID-19) causes respiratory failure and critical illness. Recently, COVID-19 has been associated with heparanase (HPSE)-induced endothelial barrier dysfunction and inflammation, so called endothelitis, and therapeutic treatment with heparin or low-molecular-weight heparin (LMWH) targeting HPSE has been postulated. Because, up to this date, clinicians are unable to measure the severity of endothelitis, which can lead to multiorgan failure and concomitant death, we investigated plasma levels of HPSE and heparin-binding protein (HBP) in COVID-19 intensive care patients to render a possible link between endothelitis and these plasma parameters. Therefore, a prospective prolonged cohort study was conducted, including 47 COVID-19 patients from the intensive care unit. Plasma levels of HPSE, and HBP were measured daily by enzyme-linked immunosorbent assay in survivors (n = 35) and nonsurvivors (n = 12) of COVID-19 from admission until discharge or death. All patients were either treated with heparin or LMWH, aiming for an activated partial thromboplastin time of ≥60 seconds or an anti-Xa level of >0.8 IU/mL using enoxaparin, depending on the clinical status of the patient (patients with extracorporeal membrane oxygenation or >0.1 µg/kg/min noradrenaline received heparin, all others enoxaparin). Results: We found significantly higher plasma levels of HPSE and HBP in survivors and nonsurvivors of COVID-19, compared with healthy controls. Still, interestingly, plasma HPSE levels were significantly higher ( P < 0.001) in survivors compared with nonsurvivors of COVID-19. In contrast, plasma HBP levels were significantly reduced ( P < 0.001) in survivors compared with nonsurvivors of COVID-19. Furthermore, when patients received heparin, they had significantly lower HPSE ( P = 2.22 e - 16) and significantly higher HBP ( P = 0.00013) plasma levels as when they received LMWH. Conclusion: Our results demonstrated that patients, who recover from COVID-19-induced vascular and pulmonary damage and were discharged from the intensive care unit, have significantly higher plasma HPSE level than patients who succumb to COVID-19. Therefore, HPSE is not suitable as marker for disease severity in COVID-19 but maybe as marker for patient's recovery. In addition, patients receiving therapeutic heparin treatment displayed significantly lower heparanse plasma level than upon therapeutic treatment with LMWH.

Cardiovascular signatures of COVID-19 predict mortality and identify barrier stabilizing therapies.

BACKGROUND: Endothelial cell (EC) activation, endotheliitis, vascular permeability, and thrombosis have been observed in patients with severe coronavirus disease 2019 (COVID-19), indicating that the vasculature is affected during the acute stages of SARS-CoV-2 infection. It remains unknown whether circulating vascular markers are sufficient to predict clinical outcomes, are unique to COVID-19, and if vascular permeability can be therapeutically targeted. METHODS: Prospectively evaluating the prevalence of circulating inflammatory, cardiac, and EC activation markers as well as developing a microRNA atlas in 241 unvaccinated patients with suspected SARS-CoV-2 infection allowed for prognostic value assessment using a Random Forest model machine learning approach. Subsequent ex vivo experiments assessed EC permeability responses to patient plasma and were used to uncover modulated gene regulatory networks from which rational therapeutic design was inferred. FINDINGS: Multiple inflammatory and EC activation biomarkers were associated with mortality in COVID-19 patients and in severity-matched SARS-CoV-2-negative patients, while dysregulation of specific microRNAs at presentation was specific for poor COVID-19-related outcomes and revealed disease-relevant pathways. Integrating the datasets using a machine learning approach further enhanced clinical risk prediction for in-hospital mortality. Exposure of ECs to COVID-19 patient plasma resulted in severity-specific gene expression responses and EC barrier dysfunction, which was ameliorated using angiopoietin-1 mimetic or recombinant Slit2-N. INTERPRETATION: Integration of multi-omics data identified microRNA and vascular biomarkers prognostic of in-hospital mortality in COVID-19 patients and revealed that vascular stabilizing therapies should be explored as a treatment for endothelial dysfunction in COVID-19, and other severe diseases where endothelial dysfunction has a central role in pathogenesis. FUNDING: This work was directly supported by grant funding from the Ted Rogers Center for Heart Research, Toronto, Ontario, Canada and the Peter Munk Cardiac Center, Toronto, Ontario, Canada.

New laboratory evidence for the association between endothelial dysfunction and COVID-19 disease progression.

There is growing evidence that angiotensin-converting enzyme 2 is highly expressed on endothelial cells, endothelial dysfunction plays a critical role in coronavirus disease 2019 (COVID-19) progression, but laboratory evidence is still lacking. This study established a multicenter retrospective cohort of 966 COVID-19 patients from three hospitals in Wuhan, China. We found that male (62.8% vs. 46.5%), old age [72 (17) vs. 60.5 (21)], and coexisting chronic diseases (88.5% vs. 60.0%) were associated with poor clinical prognosis in COVID-19. Furthermore, the deteriorated patients exhibited more severe multiorgan damage, coagulation dysfunction, and extensive inflammation. Additionally, a cross-sectional study including 41 non-COVID-19 controls and 39 COVID-19 patients assayed endothelial function parameters in plasma and showed that COVID-19 patients exhibited elevated vascular cell adhesion molecule-1 (VCAM-1) (median [IQR]: 0.32 [0.27] vs. 0.17 [0.11] µg/ml, p < 0.001), E-selectin (21.06 [12.60] vs. 11.01 [4.63] ng/ml, p < 0.001), tissue-type plasminogen activator (tPA) (0.22 [0.12] vs. 0.09 [0.04] ng/ml, p < 0.001), and decreased plasminogen activator inhibitor-1 (0.75 [1.31] vs 6.20 [5.34] ng/ml, p < 0.001), as compared to normal controls. Moreover, VCAM-1 was positively correlated with d-dimer (R = 0.544, p < 0.001); tPA was positively correlated with d-dimer (R = 0.800, p < 0.001) and blood urea nitrogen (R = 0.638, p < 0.001). Our findings further confirm the strong association between endothelial dysfunction and poor prognosis of COVID-19, which offers a rationale for targeting endothelial dysfunction as a therapeutic strategy for COVID-19.

Spontaneous right coronary artery dissection in a patient with COVID-19 infection: A case report and review of the literature.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the global coronavirus disease 2019 (COVID-19) pandemic. Although the virus predominantly causes respiratory system infection, recent reports have shown that it is also associated with many cardiovascular complications. It has been reported that COVID-19 may cause myocarditis, type 1 and 2 acute myocardial infarction, and thrombotic complications.[1] Spontaneous coronary artery dissection (SCAD) is a rare form of coronary artery disease that has recently been associated with COVID-19 in a few case reports. The case reported here is of COVID-19 associated SCAD in a patient with no history of cardiovascular disease.

Regulation of NOS expression in vascular diseases.

Nitric oxide synthases (NOS) are the major sources of nitric oxide (NO), a small bioactive molecule involved in the regulation of many cellular processes. One of the most prominent functions of NO is regulation of vasodilatation and thereby control of blood pressure. Most important for vascular tone is NOS3. Endothelial NOS3-generated NO diffuses into the vascular smooth muscle cells, activates the soluble guanylate cyclase resulting in enhanced cGMP concentrations and smooth muscle cell relaxation. However, more and more evidence exist that also NOS1 and NOS2 contribute to vascular function. We summarize the current knowledge about the regulation of NOS expression in the vasculature by transcriptional, post-transcriptional and post-translational mechanisms, in regard to inflammation and innate immune pathways.

ACE2/Ang-(1-7)/Mas1 axis and the vascular system: vasoprotection to COVID-19-associated vascular disease.

The two axes of the renin-angiotensin system include the classical ACE/Ang II/AT1 axis and the counter-regulatory ACE2/Ang-(1-7)/Mas1 axis. ACE2 is a multifunctional monocarboxypeptidase responsible for generating Ang-(1-7) from Ang II. ACE2 is important in the vascular system where it is found in arterial and venous endothelial cells and arterial smooth muscle cells in many vascular beds. Among the best characterized functions of ACE2 is its role in regulating vascular tone. ACE2 through its effector peptide Ang-(1-7) and receptor Mas1 induces vasodilation and attenuates Ang II-induced vasoconstriction. In endothelial cells activation of the ACE2/Ang-(1-7)/Mas1 axis increases production of the vasodilator's nitric oxide and prostacyclin's and in vascular smooth muscle cells it inhibits pro-contractile and pro-inflammatory signaling. Endothelial ACE2 is cleaved by proteases, shed into the circulation and measured as soluble ACE2. Plasma ACE2 activity is increased in cardiovascular disease and may have prognostic significance in disease severity. In addition to its enzymatic function, ACE2 is the receptor for severe acute respiratory syndrome (SARS)-coronavirus (CoV) and SARS-Cov-2, which cause SARS and coronavirus disease-19 (COVID-19) respectively. ACE-2 is thus a double-edged sword: it promotes cardiovascular health while also facilitating the devastations caused by coronaviruses. COVID-19 is associated with cardiovascular disease as a risk factor and as a complication. Mechanisms linking COVID-19 and cardiovascular disease are unclear, but vascular ACE2 may be important. This review focuses on the vascular biology and (patho)physiology of ACE2 in cardiovascular health and disease and briefly discusses the role of vascular ACE2 as a potential mediator of vascular injury in COVID-19.

COVID Purpura (Toes) Case Series: A Chilblains-Like Vasculopathy.

ABSTRACT: Biopsies were taken from 4 patients who presented to their dermatologist with violaceous papules and plaques of the dorsal toes (COVID Toes) associated with varying degrees of severe acute respiratory syndrome coronavirus 2 exposure and COVID-19 testing. Major histopathologic findings were lymphocytic eccrine inflammation and a spectrum of vasculopathic findings to include superficial and deep angiocentric-perivascular lymphocytic inflammation, lymphocytes in vessel walls (lymphocytic vasculitis), endothelial swelling, red blood cell extravasation, and focal deposits of fibrin in both vessel lumina, and vessel walls. Interface changes were observed to include vacuolopathy and apoptotic keratinocytes at the basement membrane. Immunostains showed a dominant T-cell lineage (positive for T-cell receptor beta, CD2, CD3, CD5, and CD7). B-cells were rare and clusters of CD123-positive dermal plasmacytoid dendritic cells were observed surrounding eccrine clusters and some perivascular zones. The consistent perieccrine and vasculopathic features represent important pathologic findings in the diagnosis of COVID toes and are suggestive of pathogenetic mechanisms. Clinicopathologic correlation, the epidemiological backdrop, and the current worldwide COVID-19 pandemic favor a viral causation and should alert the physician to initiate a workup and the appropriate use of COVID-19 testing.

Spontaneous coronary artery dissection of the left anterior descending artery in a patient with COVID-19 infection.

A 48-year-old woman with a past medical history of migraines and hyperlipidemia presented due to severe retrosternal chest pain with no other associated signs or symptoms. The patient was hemodynamically stable and was found to have an elevated troponin with electrocardiogram showing no ischemic changes. Computed tomography of the coronary arteries showed a left dominant system with dissection extending from the mid-to-distal left anterior descending (LAD) artery. The patient was subsequently discharged on medical therapy but returned 3 days later due to worsening chest pain. Electrocardiogram revealed inferior and anteroseptal ST segment changes with peak troponin of 14.9 ng/ml (reference range <0.80 ng/ml). Coronavirus disease 2019 (COVID-19) nasopharyngeal swab was performed prior to urgent coronary angiogram. Coronary angiogram was performed with full personal protective equipment for respiratory and droplet precautions due to pending COVID-19 testing results. Angiogram revealed spontaneous coronary artery dissection (SCAD) extending from the ostium of the LAD to the distal vessel. COVID-19 testing returned positive while in intensive care unit. The patient was not a percutaneous coronary intervention candidate due to the extent of the dissection and was not a surgical candidate due to a lack of graftable target and medical management was continued. To our knowledge, this case is the first in which SCAD has been reported in the LAD in a patient with COVID-19 with no other symptoms of respiratory illness or symptoms classically associated with the novel coronavirus. SCAD should be considered on the differential as one of the various cardiac manifestations of COVID-19 infection.

Severe COVID-19: A multifaceted viral vasculopathy syndrome.

The objective of this study was to elucidate the pathophysiology that underlies severe COVID-19 by assessing the histopathology and the in situ detection of infectious SARS-CoV-2 and viral capsid proteins along with the cellular target(s) and host response from twelve autopsies. There were three key findings: 1) high copy infectious virus was limited mostly to the alveolar macrophages and endothelial cells of the septal capillaries; 2) viral spike protein without viral RNA localized to ACE2+ endothelial cells in microvessels that were most abundant in the subcutaneous fat and brain; 3) although both infectious virus and docked viral spike protein was associated with complement activation, only the endocytosed pseudovirions induced a marked up-regulation of the key COVID-19 associated proteins IL6, TNF alpha, IL1 beta, p38, IL8, and caspase 3. Importantly, this microvasculitis was associated with characteristic findings on hematoxylin and eosin examination that included endothelial degeneration and resultant basement membrane zone disruption and reduplication. It is concluded that serious COVID-19 infection has two distinct mechanisms: 1) a microangiopathy of pulmonary capillaries associated with a high infectious viral load where endothelial cell death releases pseudovirions into the circulation, and 2) the pseudovirions dock on ACE2+ endothelial cells most prevalent in the skin/subcutaneous fat and brain that activates the complement pathway/coagulation cascade resulting in a systemic procoagulant state as well as the expression of cytokines that produce the cytokine storm. The data predicts a favorable response to therapies based on either removal of circulating viral proteins and/or blunting of the endothelial-induced response.

COVID-19 - A vascular disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to multi-system dysfunction with emerging evidence suggesting that SARS-CoV-2-mediated endothelial injury is an important effector of the virus. Potential therapies that address vascular system dysfunction and its sequelae may have an important role in treating SARS-CoV-2 infection and its long-lasting effects.

Vascular obliteration because of endothelial and myointimal growth in COVID-19 patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a systemic multi-organ viral illness. Previous studies have found that many patients had a procoagulant state and/or severe hypoxemia with relatively well-preserved lung mechanics. Mechanisms underlying the damage to vascular tissues are not well-elucidated yet. Histological data in COVID-19 patients are still limited and are mainly focused on post-mortem analysis. Given that the skin is affected by COVID-19 and the relative ease of its histological examination, we aimed to examine the histology of skin lesions in COVID-19 patients to better understand the disease's pathology. METHODS: Five skin lesions from COVID-19 adult patients were selected for a deep histological tissue examination. RESULTS: A strong vasculopathic reaction pattern based on prominent vascular endothelial and myointimal cell growth was identified. Endothelial cell distortion generated vascular lumen obliteration and striking erythrocyte and serum extravasation. Significant deposition of C4d and C3 throughout the vascular cell wall was also identified. A regenerative epidermal hyperplasia with tissue structure preservation was also observed. CONCLUSIONS: COVID-19 could comprise an obliterative microangiopathy consisting on endothelial and myointimal growth with complement activation. This mechanism, together with the increased vascular permeability identified, could contribute to obliteration of the vascular lumen and hemorrhage in COVID-19. Thus, anticoagulation by itself could not completely reverse vascular lumen obliteration, with consequent increased risk of hemorrhage. Findings of this study could contribute to a better understanding of physiopathological mechanisms underlying COVID-19 on living patients and could help further studies find potential targets for specific therapeutic interventions in severe cases.

Vascular Endothelial Glycocalyx Damage in COVID-19.

The new coronavirus disease-2019 (COVID-19), which is spreading around the world and threatening people, is easily infecting a large number of people through airborne droplets; moreover, patients with hypertension, diabetes, obesity, and cardiovascular disease are more likely to experience severe conditions. Vascular endothelial dysfunction has been suggested as a common feature of high-risk patients prone to severe COVID-19, and measurement of vascular endothelial function may be recommended for predicting severe conditions in high-risk patients with COVID-19. However, fragmented vascular endothelial glycocalyx (VEGLX) is elevated in COVID-19 patients, suggesting that it may be useful as a prognostic indicator. Although the relationship between VEGLX and severe acute respiratory syndrome coronavirus 2 infections has not been well studied, some investigations into COVID-19 have clarified the relationship between VEGLX and the mechanism that leads to severe conditions. Clarifying the usefulness of VEGLX assessment as a predictive indicator of the development of severe complications is important as a strategy for confronting pandemics caused by new viruses with a high affinity for the vascular endothelium that may recur in the future.

Non-invasive assessment of endothelial dysfunction: A novel method to predict severe COVID-19?

The COVID-19 pandemic caused by the SARS-CoV-2 virus has infected millions and overburdened the healthcare infrastructure globally. Recent studies show that the endothelial dysfunction caused by the virus contributes to its high morbidity and mortality. A parameter that can identify patients who will develop complications early will be valuable in patient management and reducing the burden on medical resources. An emerging technology is currently being tested to predict the cardiovascular risk via non-invasively measuring the endothelial dysfunction. This paper reviews how the assessment of endothelial dysfunction using this technology can be used as a potential parameter in the prognostication and management of COVID-19 patients.

SARS-CoV-2 cell entry receptor ACE2 mediated endothelial dysfunction leads to vascular thrombosis in COVID-19 patients.

Several studies have described unusually high incidence of vascular thrombosis in coronavirus disease-2019 (COVID-19) patients. Pathogenesis of the vascular thrombosis in COVID-19 is least understood for now and presents a challenge to the treating physicians. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative pathogen for COVID-19, has been shown to bind to angiotensin converting enzyme 2 (ACE2) protein in human epithelial cells which facilitates its entry in the organ and mediate tissue specific pathogenesis. For ACE2 mediated cell entry of the SARS-CoV-2, co-expression of one more protein-Transmembrane protease serine 2 (TMPRSS2) is essential. Existing studies suggested significant expression of ACE2 and TMPRSS2 in human vascular endothelium. Vascular endothelial dysfunction can potentially activate coagulation cascade eventually resulting in thrombosis. ACE2 has proven role in the maintenance of endothelial integrity inside the vessels. Existing in situ evidence for SARS-CoV-1 (the causative agent for SARS pandemic of 2002, which shared ACE2 as cell entry receptor) suggested that virus binding can downregulate ACE2, thus can induce endothelial dysfunction. Recently, in situ evidence has been presented that SARS-CoV-2 can infect cells in engineered human vascular endothelium, which can be effectively blocked by using clinical-grade recombinant human ACE2. Based on the circumstantial evidence present in the literature, we propose a SARS-CoV-2 cell entry receptor ACE2 based mechanism for vascular thrombosis in COVID-19 patients.

An interesting case of small vessel pathology following coronavirus infection.

Vasculitis is a descriptive term for a wide variety of conditions characterised by inflammation of the blood vessels that may occur as a primary process or secondary to an underlying disease. Occlusive vasculopathy is a different clinical entity characterised by skin changes and ulceration of the lower extremities because of thrombosis of the small vessels of the dermis and is usually associated with pre-thrombotic conditions. Both conditions can be confirmed or excluded by skin biopsy. We report the case of a 63-year-old woman presenting with upper and lower respiratory tract symptoms followed by a vasculitic rash on both legs. The patient underwent extensive radiological and laboratory investigations that were negative apart from positive coronavirus OC43. A biopsy of the skin was performed. Considering the clinical presentation and the investigations performed, the diagnosis of small vessel vasculopathy following coronavirus OC43 has been suggested by the authors.