Endotheliopathy in Acute COVID-19 and Long COVID.

The pulmonary endothelium is a highly regulated organ that performs a wide range of functions under physiological and pathological conditions. Since endothelial dysfunction has been demonstrated to play a direct role in sepsis and acute respiratory distress syndrome, its role in COVID-19 has also been extensively investigated. Indeed, apart from the COVID-19-associated coagulopathy biomarkers, new biomarkers were recognised early during the pandemic, including markers of endothelial cell activation or injury. We systematically searched the literature up to 10 March 2023 for studies examining the association between acute and long COVID-19 severity and outcomes and endothelial biomarkers.

Significance of Catecholamine Biosynthetic/Metabolic Pathway in SARS-CoV-2 Infection and COVID-19 Severity.

The SARS-CoV-2 infection was previously associated with the expression of the dopamine biosynthetic enzyme L-Dopa decarboxylase (DDC). Specifically, a negative correlation was detected between DDC mRNA and SARS-CoV-2 RNA levels in in vitro infected epithelial cells and the nasopharyngeal tissue of COVID-19 patients with mild/no symptoms. However, DDC, among other genes related to both DDC expression and SARS-CoV-2-infection (ACE2, dACE2, EPO), was upregulated in these patients, possibly attributed to an orchestrated host antiviral response. Herein, by comparing DDC expression in the nasopharyngeal swab samples of severe/critical to mild COVID-19 cases, we showed a 20 mean-fold reduction, highlighting the importance of the expression of this gene as a potential marker of COVID-19 severity. Moreover, we identified an association of SARS-CoV-2 infection with the expression of key catecholamine biosynthesis/metabolism-related genes, in whole blood samples from hospitalized patients and in cultured cells. Specifically, viral infection downregulated the biosynthetic part of the dopamine pathway (reduction in DDC expression up to 7.5 mean-fold), while enhanced the catabolizing part (increase in monoamine oxidases A and B expression up to 15 and 10 mean-fold, respectively) in vivo, irrespectively of the presence of comorbidities. In accordance, dopamine levels in the sera of severe cases were reduced (up to 3.8 mean-fold). Additionally, a moderate positive correlation between DDC and MAOA mRNA levels (r = 0.527, p < 00001) in the blood was identified upon SARS-CoV-2-infection. These observations were consistent to the gene expression data from SARS-CoV-2-infected Vero E6 and A549 epithelial cells. Furthermore, L-Dopa or dopamine treatment of infected cells attenuated the virus-derived cytopathic effect by 55% and 59%, respectively. The SARS-CoV-2 mediated suppression of dopamine biosynthesis in cell culture was, at least in part, attributed to hypoxia-like conditions triggered by viral infection. These findings suggest that L-Dopa/dopamine intake may have a preventive or therapeutic value for COVID-19 patients.

COMPARATIVE EVALUATION AND PROGNOSTIC UTILITY OF NEURONAL INJURY BIOMARKERS IN COVID-19 PATIENTS: A PROSPECTIVE STUDY.

ABSTRACT: Background : COVID-19 disease severity markers include mostly molecules related to not only tissue perfusion, inflammation, and thrombosis, but also biomarkers of neural injury. Clinical and basic research has demonstrated that SARS-COV-2 affects the central nervous system. The aims of the present study were to investigate the role of neural injury biomarkers and to compare them with inflammatory markers in their predictive ability of mortality. Methods : We conducted a prospective observational study in critically ill patients with COVID-19 and in a cohort of patients with moderate/severe disease. S100b, neuron-specific enolase (NSE), and inflammatory markers, including soluble urokinase plasminogen activator receptor (suPAR), were measured on intensive care unit or ward admission, respectively. Statistical comparisons between patient groups were performed for all biomarkers under investigation. Correlations between different biomarkers were tested with Spearman correlation coefficient. Receiver operating characteristic curves were plotted using mortality as the classification variable and the biomarker levels on admission as the prognostic variables. Results : A total of 70 patients with COVID-19 were included in the final analysis. Of all studied biomarkers, s100b had the best predictive ability for death in the intensive care unit, with an area under the curve of 0.73 (0.61-0.83), P = 0.0003. S100b levels correlated with NSE, interleukin (IL)-8, and IL-10 (0.27 < rs < 0.37, P < 0.05), and tended to correlate with suPAR ( rs = 0.26, P = 0.05), but not with the vasopressor dose ( P = 0.62). Conclusion : Among the investigated biomarkers, s100b demonstrated the best predictive ability for death in COVID-19 patients. The overall biomarker profile of the patients implies direct involvement of the nervous system by the novel coronavirus.

Endocrine Aspects of ICU-Hospitalized COVID-19 Patients.

The unprecedented scale of the current SARS-CoV-2/COVID-19 pandemic has led to an extensive-yet fragmented-assessment of its endocrine repercussions; in many reports, the endocrine aspects of COVID-19 are lumped together in intensive care unit (ICU) patients and non-ICU patients. In this brief review, we aimed to present endocrine alterations in ICU-hospitalized patients with COVID-19. There are tangible endocrine disturbances that may provide fertile ground for COVID-19, such as preexisting diabetes. Other endocrine disturbances accompany the disease and more particularly its severe forms. Up to the time of writing, no isolated robust endocrine/hormonal biomarkers for the prognosis of COVID-19 have been presented. Among those which may be easily available are admission glycemia, thyroid hormones, and maybe (OH)25-vitamin D3. Their overlap among patients with severe and less severe forms of COVID-19 may be considerable, so their levels may be indicative only. We have shown that insulin-like growth factor 1 may have prognostic value, but this is not a routine measurement. Possibly, as our current knowledge is expanding, the inclusion of selected routine endocrine/hormonal measurements into artificial intelligence/machine learning models may provide further information.

Testosterone, free, bioavailable and total, in patients with COVID-19.

BACKGROUND: Low testosterone (mainly total testosterone [TTe]) has been noted in patients with COVID-19. Calculated free testosterone (FTe) and bioavailable testosterone (BavTe) may reflect more accurately this hormone's levels. In this study, we sought to assess TTe, FTe as well as BavTe in male patients with COVID-19. METHODS: Sera were collected upon admission from 65 men (10 in the intensive care units [ICU] and 55 in the wards) with polymerase chain reaction - proven COVID-19. A group of age-matched COVID-19-negative men (N.=29) hospitalized in general medical wards served as controls. Age, Body Mass Index (BMI) and 28-day mortality were noted. Measurements included TTe, sex-hormone binding globulin, albumin (the latter two for calculating FTe and BavTe) and laboratory markers of inflammation (white blood cell count [WBC], D-Dimers [D-D], lactate dehydrogenase [LDH], ferritin [Fer] and C-reactive protein [CRP]). RESULTS: Profoundly low TTe, FTe and BavTe were noted in most patients, and were associated with disease severity/outcome (being the lowest in COVID-19 patients in the ICU and overall being lower in non-survivors; analysis of covariance P<0.05). Pearson's correlations for logTe, logFTe or logBavTe versus WBC, D-D, LDH, Ferr or CRP were negative, ranging from -0.403 to -0.293 (P=0.009 to 0.014). CONCLUSIONS: TTe, FTe and BavTe are prone to be low in patients with COVID-19, are negatively associated with disease severity and may be considered to have prognostic value.

Comparison of the Mortality Prediction Value of Soluble Urokinase Plasminogen Activator Receptor (suPAR) in COVID-19 and Sepsis.

In the last years, biomarkers of infection, such as the soluble urokinase plasminogen activator receptor (suPAR), have been extensively studied as potential diagnostic and prognostic biomarkers in the intensive care unit (ICU). In this study, we investigated whether this biomarker can be used in COVID-19 and non-COVID-19 septic patients for mortality prediction. Serum suPAR levels were measured in 79 non-COVID-19 critically ill patients upon sepsis (within 6 h), and on admission in 95 COVID-19 patients (66 critical and 29 moderate/severe). The non-COVID-19 septic patients were matched for age, sex, and disease severity, while the site of infection was the respiratory system. On admission, COVID-19 patients presented with higher suPAR levels, compared to non-COVID-19 septic patients (p < 0.01). More importantly, suPAR measured upon sepsis could not differentiate survivors from non-survivors (p > 0.05), as opposed to suPAR measured on admission in COVID-19 survivors and non-survivors (p < 0.0001). By the generated ROC curve, the prognostic value of suPAR in COVID-19 was 0.81, at a cut-off value of 6.3 ng/mL (p < 0.0001). suPAR measured early (within 24 h) after hospital admission seems like a specific and sensitive mortality risk predictor in COVID-19 patients. On the contrary, suPAR measured at sepsis diagnosis in non-COVID-19 critically ill patients, does not seem to be a prognostic factor of mortality.

Increase of HO-1 Expression in Critically Ill COVID-19 Patients Is Associated with Poor Prognosis and Outcome.

Heme-oxygenase (HO)-1 is a cytoprotective enzyme with strong antioxidant and anti-apoptotic properties and previous reports have also emphasized the antiviral properties of HO-1, either directly or via induction of interferons. To investigate the potential role of HO-1 in patients with coronavirus disease 2019 (COVID-19), the present study assessed changes in HO-1 expression in whole blood and tissue samples. Upregulation of HO-1 protein was observed in lung, liver, and skin tissue independently of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presence. A significant increase of blood HO-1 mRNA levels was observed in critically ill COVID-19 patients compared to those in severe COVID-19 patients and healthy controls. This increase was accompanied by significantly elevated levels of serum ferritin and bilirubin in critically ill compared to patients with severe disease. Further grouping of patients in survivors and non-survivors revealed a significant increase of blood HO-1 mRNA levels in the later. Receiver operating characteristic (ROC) analysis for prediction of ICU admission and mortality yielded an AUC of 0.705 (p = 0.016) and 0.789 (p = 0.007) respectively indicating that HO-1 increase is associated with poor COVID-19 progression and outcome. The increase in HO-1 expression observed in critically ill COVID-19 patients could serve as a mechanism to counteract increased heme levels driving coagulation and thrombosis or as an induced protective mechanism.

Lactate and Lactate-to-Pyruvate Ratio in Critically Ill COVID-19 Patients: A Pilot Study.

A limited number of coronavirus disease-19 (COVID-19) cases may require treatment in an intensive care unit (ICU). Arterial blood lactate levels are routinely measured in the ICU to estimate disease severity, predict poor outcomes, and monitor therapeutic handlings. A number of studies have suggested that, simultaneously with lactate, pyruvate should also be measured, providing augmented prognostic ability, and a better understanding of the underlying metabolic alterations in ICU patients. Hence, the aim of the present study was to elucidate the relationship between lactate levels and the lactate-to-pyruvate (LP) ratio with the clinical outcome in mechanically ventilated COVID-19 patients. Lactate and pyruvate were serially measured during the first 24 h of ICU stay. A group of ICU non-COVID-19 patients was used as a comparison group. The majority of COVID-19 patients (82.5%) had normal lactate levels and a normal LP ratio on ICU admission (normal metabolic pattern). A small, yet significant, percentage of patients had either elevated lactate levels or a high LP ratio (abnormal metabolic pattern); these patients exhibited a significantly higher risk of ICU mortality compared to the patients with a normal metabolic pattern (72.7% vs. 34.6%, p = 0.04). In our critically ill COVID-19 patients, elevated lactate levels or high LP ratios on admission to the ICU could be associated with poor clinical outcome.

Endothelial, Immunothrombotic, and Inflammatory Biomarkers in the Risk of Mortality in Critically Ill COVID-19 Patients: The Role of Dexamethasone.

Endothelial dysfunction, coagulation and inflammation biomarkers are increasingly emerging as prognostic markers of poor outcomes and mortality in severe and critical COVID-19. However, the effect of dexamethasone has not been investigated on these biomarkers. Hence, we studied potential prognostic biomarkers of mortality in critically ill COVID-19 patients who had either received or not dexamethasone. Biomarker serum levels were measured on intensive care unit (ICU) admission (within 24 h) in 37 dexamethasone-free and 29 COVID-19 patients who had received the first dose (6 mg) of dexamethasone. Receiver operating characteristic (ROC) curves were generated to assess their value in ICU mortality prediction, while Kaplan-Meier analysis was used to explore associations between biomarkers and survival. In the dexamethasone-free COVID-19 ICU patients, non-survivors had considerably higher levels of various endothelial, immunothrombotic and inflammatory biomarkers. In the cohort who had received one dexamethasone dose, non-survivors had higher ICU admission levels of only soluble (s) vascular cell adhesion molecule-1 (VCAM-1), soluble urokinase-type plasminogen activator receptor (suPAR) and presepsin. As determined from the generated ROC curves, sVCAM-1, suPAR and presepsin could still be reliable prognostic ICU mortality biomarkers, following dexamethasone administration (0.7 < AUC < 0.9). Moreover, the Kaplan-Meier survival analysis showed that patients with higher than the median values for sVCAM-1 or suPAR exhibited a greater mortality risk than patients with lower values (Log-Rank test, p < 0.01). In our single-center study, sVCAM-1, suPAR and presepsin appear to be valuable prognostic biomarkers in assessing ICU mortality risk in COVID-19 patients, even following dexamethasone administration.

Increased Glucocorticoid Receptor Alpha Expression and Signaling in Critically Ill Coronavirus Disease 2019 Patients.

OBJECTIVES: Critical illness is characterized by increased serum cortisol concentrations and bioavailability resulting from the activation of the hypothalamic-pituitary-adrenal axis, which constitutes an essential part of the stress response. The actions of glucocorticoids are mediated by a ubiquitous intracellular receptor protein, the glucocorticoid receptor. So far, data on coronavirus disease 2019 and glucocorticoid receptor alpha expression are lacking. DESIGN: Prospective observational study. SETTING: One academic multidisciplinary ICU. SUBJECTS: Twenty-six adult coronavirus disease 2019 patients; 33 adult noncoronavirus disease 2019 patients, matched for age, sex, and disease severity, constituted the control group. All patients were steroid-free. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Glucocorticoid receptor alpha, glucocorticoid-inducible leucine zipper expression, and serum cortisol were measured on ICU admission. In coronavirus disease 2019 patients, glucocorticoid receptor alpha and glucocorticoid-inducible leucine zipper messenger RNA expression were upregulated (4.7-fold, p < 0.01 and 14-fold, p < 0.0001, respectively), and cortisol was higher (20.3 vs 14.3 µg/dL, p < 0.01) compared with the control group. CONCLUSIONS: ICU coronavirus disease 2019 patients showed upregulated glucocorticoid receptor alpha and glucocorticoid-inducible leucine zipper expression, along with cortisol levels, compared with ICU noncoronavirus disease 2019 patients. Thus, on ICU admission, critical coronavirus disease 2019 appears to be associated with hypercortisolemia, and increased synthesis of glucocorticoid receptor alpha and induced proteins.

Pituitary-Adrenal Responses and Glucocorticoid Receptor Expression in Critically Ill Patients with COVID-19.

The hypothalamus-pituitary-adrenal (HPA) axis was described as the principal component of the stress response 85 years ago, along with the acute-phase reaction, and the defense response at the tissue level. The orchestration of these processes is essential since systemic inflammation is a double-edged sword; whereas inflammation that is timely and of appropriate magnitude is beneficial, exuberant systemic inflammation incites tissue damage with potentially devastating consequences. Apart from its beneficial cardiovascular and metabolic effects, cortisol exerts a significant immunoregulatory role, a major attribute being that it restrains the excessive inflammatory reaction, thereby preventing unwanted tissue damage. In this review, we will discuss the role of the HPA axis in the normal stress response and in critical illness, especially in critically ill patients with coronavirus disease 2019 (COVID-19). Finally, a chapter will be dedicated to the findings from clinical studies in critical illness and COVID-19 on the expression of the mediator of glucocorticoid actions, the glucocorticoid receptor (GCR).

Low Admission Immunoglobulin G Levels Predict Poor Outcome in Patients with Mild-to-Critical COVID-19: A Prospective, Single-Center Study.

INTRODUCTION: Immunoglobulins (Igs) comprise a critical part of the immune response. Little information exists on Ig serum levels in COVID-19 patients. We, therefore, investigated whether hospital admission Igs in patients with mild-to-critical disease are associated with clinical outcome. MATERIALS AND METHODS: This prospective, observational, single-center, cross-sectional study included 126 consecutive non-critically ill and critically ill and COVID-19 patients, in whom IgG, IgM, and IgA were measured on hospital admission. RESULTS: The cohort was divided in survivors and non-survivors, based on in-hospital mortality. Median IgG levels of survivors were significantly higher than non-survivors (p < 0.01). The cohort was subsequently divided in IgG deficient (< 690 mg/dl) and sufficient (≥ 690 mg/dl) patients. IgG-deficient patients had a higher mortality rate (p < 0.01). The multivariate logistic regression model showed that subnormal IgG was significantly associated with increased mortality risk (p < 0.01). CONCLUSION: In our COVID-19 cohort, admission subnormal IgG levels might be independently associated with reduced survival.

Evaluating the Role of the Interleukin-23/17 Axis in Critically Ill COVID-19 Patients.

Studies have hypothesized a potential role of the interleukin (IL)-23/17 axis in coronavirus disease 2019 (COVID-19). However, to date, levels of IL-23 and 17 have not been compared between critically ill COVID-19 patients and critically ill non-COVID-19 patients. IL-23 and 17 were measured on admission to the intensive care unit (ICU) in critically ill COVID-19 (N = 38) and critically ill non-COVID-19 (N = 34) patients with an equal critical illness severity. Critically ill non-COVID-19 patients did not have sepsis or septic shock on ICU admission. None of the enrolled patients had previously received corticosteroids. In our study, circulating IL-17 levels were higher in the COVID-19 patients. More specifically, critically ill COVID-19 patients had levels of 0.78 (0.05-1.8) pg/mL compared to 0.11 (0.05-0.9) pg/mL in the critically ill non-COVID-19 patients (p = 0.04). In contrast, IL-23 levels were comparable between groups. A group of patients hospitalized in the specialized COVID-19 clinic (N = 16) was also used to evaluate IL-17 and IL-23 levels with respect to COVID-19 severity. Non-critically ill COVID-19 patients had undetectable levels of both cytokines. Our results support the notion of inhibiting IL-17 in critical COVID-19 infection.

Increased Autotaxin Levels in Severe COVID-19, Correlating with IL-6 Levels, Endothelial Dysfunction Biomarkers, and Impaired Functions of Dendritic Cells.

Autotaxin (ATX; ENPP2) is a secreted lysophospholipase D catalyzing the extracellular production of lysophosphatidic acid (LPA), a pleiotropic signaling phospholipid. Genetic and pharmacologic studies have previously established a pathologic role for ATX and LPA signaling in pulmonary injury, inflammation, and fibrosis. Here, increased ENPP2 mRNA levels were detected in immune cells from nasopharyngeal swab samples of COVID-19 patients, and increased ATX serum levels were found in severe COVID-19 patients. ATX serum levels correlated with the corresponding increased serum levels of IL-6 and endothelial damage biomarkers, suggesting an interplay of the ATX/LPA axis with hyperinflammation and the associated vascular dysfunction in COVID-19. Accordingly, dexamethasone (Dex) treatment of mechanically ventilated patients reduced ATX levels, as shown in two independent cohorts, indicating that the therapeutic benefits of Dex include the suppression of ATX. Moreover, large scale analysis of multiple single cell RNA sequencing datasets revealed the expression landscape of ENPP2 in COVID-19 and further suggested a role for ATX in the homeostasis of dendritic cells, which exhibit both numerical and functional deficits in COVID-19. Therefore, ATX has likely a multifunctional role in COVID-19 pathogenesis, suggesting that its pharmacological targeting might represent an additional therapeutic option, both during and after hospitalization.

Soluble Angiotensin Converting Enzyme 2 (ACE2) Is Upregulated and Soluble Endothelial Nitric Oxide Synthase (eNOS) Is Downregulated in COVID-19-induced Acute Respiratory Distress Syndrome (ARDS).

A damaged endothelium is an underlying condition of the many complications of COVID-19 patients. The increased mortality risk associated with diseases that have underlying endothelial dysfunction, such as acute respiratory distress syndrome (ARDS), suggests that endothelial (e) nitric oxide synthase (NOS)-derived nitric oxide could be an important defense mechanism. Additionally, intravenous recombinant angiotensin converting enzyme 2 (ACE2) was recently reported as an effective therapy in severe COVID-19, by blocking viral entry, and thus reducing lung injury. Very few studies exist on the prognostic value of endothelium-related protective molecules in severe COVID-19 disease. To this end, serum levels of eNOS, inducible (i) NOS, adrenomedullin (ADM), soluble (s) ACE2 levels, and serum (s) ACE activity were measured on hospital admission in 89 COVID-19 patients, hospitalized either in a ward or ICU, of whom 68 had ARDS, while 21 did not. In our cohort, the COVID-19-ARDS patients had considerably lower eNOS levels compared to the COVID-19 non-ARDS patients. On the other hand, sACE2 was significantly higher in the ARDS patients. iNOS, ADM and sACE activity did not differ. Our results might support the notion of two distinct defense mechanisms in COVID-19-derived ARDS; eNOS-derived nitric oxide could be one of them, while the dramatic rise in sACE2 may also represent an endogenous mechanism involved in severe COVID-19 complications, such as ARDS. These results could provide insight to therapeutical applications in COVID-19.

Thyroid hormone alterations in critically and non-critically ill patients with SARS-CoV-2 infection.

OBJECTIVE: Following the evolution of COVID-19 pandemic, reports pointed on a high prevalence of thyroiditis-related thyrotoxicosis. Interpretation of thyroid tests during illness, however, is hampered by changes occurring in the context of non-thyroidal illness syndrome (NTIS). In order to elucidate these findings, we studied thyroid function in carefully selected cohorts of COVID-19 positive and negative patients. DESIGN: Cohort observational study. METHODS: We measured TSH, FT4, T3 within 24 h of admission in 196 patients without thyroid disease and/or confounding medications. In this study, 102 patients were SARS-CoV-2 positive; 41 admitted in the ICU, 46 in the ward and 15 outpatients. Controls consisted of 94 SARS-CoV-2 negative patients; 39 in the ICU and 55 in the ward. We designated the thyroid hormone patterns as consistent with NTIS, thyrotoxicosis and hypothyroidism. RESULTS: A NTIS pattern was encountered in 60% of ICU and 36% of ward patients, with similar frequencies between SARS-CoV-2 positive and negative patients (46.0% vs 46.8%, P = NS). A thyrotoxicosis pattern was observed in 14.6% SARS-CoV-2 ICU patients vs 7.7% in ICU negative (P = NS) and, overall in 8.8% of SARS-CoV-2 positive vs 7.4% of negative patients. In these patients, thyroglobulin levels were similar to those with normal thyroid function or NTIS. The hypothyroidism pattern was rare. CONCLUSIONS: NTIS pattern is common and relates to the severity of disease rather than SARS-CoV-2 infection. A thyrotoxicosis pattern is less frequently observed with similar frequency between patients with and without COVID-19. It is suggested that thyroid hormone monitoring in COVID-19 should not differ from other critically ill patients.

Vitamin D in infectious complications in critically ill patients with or without COVID-19.

25-hydroxyvitamin D [25(OH)D] is an important immunomodulator, whose deficiency may aggravate the incidence and outcome of infectious complications in patients admitted to the intensive care unit. The most recognized extra-skeletal action of vitamin D is the regulation of immune function. Host defense against intracellular pathogens depends upon both innate and adaptive immunity. It has been suggested that vitamin D regulates the pro-inflammatory endothelial response to lipopolysaccharide, rendering it a role in the sepsis cascade. Recent studies have indicated that vitamin D deficiency may be associated with worse outcomes in patients with coronavirus disease 2019 (COVID-19), such as more severe disease and higher mortality rates. To this end, clinical trials with vitamin D supplementation are being carried out in an effort to improve COVID-19 outcomes. In this review, we will discuss the role of vitamin D in the immune response, and more specifically its effect on immune cells. Subsequently, we will provide an overview of the studies that have investigated the predictive value of vitamin D in critical illness outcomes, and its therapeutic value as a supplement in critically ill patients. Finally, the emerging role of vitamin D deficiency in COVID-19 infection risk, and worse outcomes will be discussed.

Covid-19 and Growth Hormone/Insulin-Like Growth Factor 1: Study in Critically and Non-Critically Ill Patients.

Objective: We aimed to measure insulin-like growth factor 1 (IGF1) and growth hormone (GH) in critically and non-critically ill patients with Covid-19 and assess them vis-a-vis clinical and laboratory parameters and prognostic tools. Subjects and Methods: We included patients who were admitted to the wards or the ICU of the largest Covid-19 referral hospital in Greece; patients with non-Covid-19 pneumonia served as controls. Apart from the routine laboratory work-up for Covid-19 we measured GH and IGF1 (and calculated normalized IGF-1 values as standard deviation scores; SDS), after blood sampling upon admission to the wards or the ICU. Results: We studied 209 critically and non-critically ill patients with Covid-19 and 39 control patients. Patients with Covid-19 who were ICU non-survivors were older and presented with a worse hematological/biochemical profile (including white blood cell count, troponin, glucose, aminotransferases and lactate dehydrogenase) compared to ICU survivors or Covid-19 survivors in the wards. Overall, IGF-1 SDS was higher in Covid-19 survivors compared to non-survivors (-0.96 ± 1.89 vs -2.05 ± 2.48, respectively, p=0.030). No significant differences were noted in GH between the groups. Nevertheless, in critically ill patients with Covid-19, the prognostic value of IGF-1 (raw data), IGF-1 (SDS) and GH for survival/non-survival was on a par with that of APACHE II and SOFA (with a marginal difference between GH and SOFA). Conclusion: In conclusion, our findings suggest that there might be an association between low IGF1 (and possibly GH) and poor outcome in patients with Covid-19.

Alteration of L-Dopa decarboxylase expression in SARS-CoV-2 infection and its association with the interferon-inducible ACE2 isoform.

L-Dopa decarboxylase (DDC) is the most significantly co-expressed gene with ACE2, which encodes for the SARS-CoV-2 receptor angiotensin-converting enzyme 2 and the interferon-inducible truncated isoform dACE2. Our group previously showed the importance of DDC in viral infections. We hereby aimed to investigate DDC expression in COVID-19 patients and cultured SARS-CoV-2-infected cells, also in association with ACE2 and dACE2. We concurrently evaluated the expression of the viral infection- and interferon-stimulated gene ISG56 and the immune-modulatory, hypoxia-regulated gene EPO. Viral load and mRNA levels of DDC, ACE2, dACE2, ISG56 and EPO were quantified by RT-qPCR in nasopharyngeal swab samples from COVID-19 patients, showing no or mild symptoms, and from non-infected individuals. Samples from influenza-infected patients were analyzed in comparison. SARS-CoV-2-mediated effects in host gene expression were validated in cultured virus-permissive epithelial cells. We found substantially higher gene expression of DDC in COVID-19 patients (7.6-fold; p = 1.2e-13) but not in influenza-infected ones, compared to non-infected subjects. dACE2 was more elevated (2.9-fold; p = 1.02e-16) than ACE2 (1.7-fold; p = 0.0005) in SARS-CoV-2-infected individuals. ISG56 (2.5-fold; p = 3.01e-6) and EPO (2.6-fold; p = 2.1e-13) were also increased. Detected differences were not attributed to enrichment of specific cell populations in nasopharyngeal tissue. While SARS-CoV-2 virus load was positively associated with ACE2 expression (r≥0.8, p<0.001), it negatively correlated with DDC, dACE2 (r≤-0.7, p<0.001) and EPO (r≤-0.5, p<0.05). Moreover, a statistically significant correlation between DDC and dACE2 expression was observed in nasopharyngeal swab and whole blood samples of both COVID-19 and non-infected individuals (r≥0.7). In VeroE6 cells, SARS-CoV-2 negatively affected DDC, ACE2, dACE2 and EPO mRNA levels, and induced cell death, while ISG56 was enhanced at early hours post-infection. Thus, the regulation of DDC, dACE2 and EPO expression in the SARS-CoV-2-infected nasopharyngeal tissue is possibly related with an orchestrated antiviral response of the infected host as the virus suppresses these genes to favor its propagation.

Could Soluble Endothelial Protein C Receptor Levels Recognize SARS-CoV2-Positive Patients Requiring Hospitalization?

INTRODUCTION: The endothelial protein C receptor (EPCR) is a protein that regulates the protein C anticoagulant and anti-inflammatory pathways. A soluble form of EPCR (sEPCR) circulates in plasma and inhibits activated protein C (APC) activities. The clinical impact of sEPCR and its involvement in COVID-19 has not been explored. In this study, we investigated whether sEPCR levels were related to COVID-19 patients' requirement for hospitalization. METHODS: Plasma sEPCR levels were measured on hospital admission in 84 COVID-19 patients, and in 11 non-hospitalized SARS-CoV2-positive patients approximately 6 days after reported manifestation of their symptoms. Multiple logistic regression analysis was performed to identify potential risk factors for hospitalization and receiver operating characteristic (ROC) curves were generated to assess their value. RESULTS: In our cohort, hospitalized patients had considerably higher sEPCR levels upon admission compared with outpatients [107.5 (76.7-156.3) vs. 44.6 (12.1-84.4) ng/mL; P < 0.0001)]. The ROC curve using hospitalization as the classification variable and sEPCR levels as the prognostic variable generated an area under the curve at 0.845 (95% CI = 0.710-0.981, P < 0.001). Additionally, we investigated the predictive value of sEPCR combined with BMI, age, or D-dimers. CONCLUSIONS: In our cohort, sEPCR levels in COVID-19 patients upon hospital admission appear considerably elevated compared with outpatients; this could lead to impaired APC activities and might contribute to the pro-coagulant phenotype reported in such patients. sEPCR measurement might be useful as a point-of-care test in SARS-CoV2-positive patients.