Biomarkers in COVID-19: Association with disease severity and outcomes

Background: In coronavirus disease 2019 (COVID-19) the need for intervention increases with disease severity and a risk prediction model that incorporates biomarkers would be beneficial for identifying patients for treatment escalation. Aim(s): To investigate biomarkers changes associated with disease severity and outcomes (mortality, thrombosis). Method(s): COVID-19 patients were sampled between April 15 and May 31 2020. Disease severity was assessed by World Health Organization (WHO) ordinal scale. 132 systemic biomarkers were investigated by routine and multiplex assays and statistical analysis performed to characterise the biomarker profile of COVID-19 patients associated with disease severity, duration, survival and thrombosis. Result(s): The study enrolled 150 COVID-19 positive adults and 16 healthy volunteers. The average age was 64 years, 59% were male, 85% had co-morbidities, 33% had a thrombotic event, and 13% died. A cross comparative analysis of biomarkers identified 13 biomarkers common to severity, mortality and thrombosis with significant correlation;including endothelial dysfunction (VWF, tPA, TFPI), hypercatabolism (low albumin, Hb, FXIII) and inflammatory response (IL-8, Osteopontin). Similarly, 14 biomarkers associated with severity and mortality included pro-inflammatory cytokines and their receptors (sTNFRII, STNFRI, sIL2a, IL6, MIP1a), neutrophils (elevated WBC, Neutrophils, TIMP1) and tissue remodelling (SCGF, EG3A). Nine biomarkers common across severity and thrombosis were angiogenesis (VEGF, LYVE1, Follistatin), acute phase response (SAP, AGP) and clot formation (Fibrinogen and PAPs). Conclusion(s): The biomarker profile associated with poorer outcomes indicates an inflammatory response, endothelial cell disruption, hypercoagulability and hypercatabolism. This study has identified several biomarkers that may be useful indicators of disease severity and progression. Further work is needed to determine how these may be used to direct clinical management. (Figure Presented).

FXR INHIBITION AS A NEW STRATEGY AGAINST COVID19 T Brevini1, M Maes2, GJ Webb3, CD Fuchs4, G Buescher5

Introduction: Vaccines revolutionised the management of COVID19. Nevertheless, they lack efficacy in high-risk or vulnerable groups (e.g., immunosuppressed patients), who may not mount an appropriate immune response. Monoclonal antibodies represent the gold-standard agents for such cases;but they are limited by availability, need for parenteral administration and the risk for viral escape because of spike protein mutations. Therefore, there is a pressing need for new prophylactic agents less prone to resistance.The viral receptor ACE2 represents an ideal target as it is essential for viral entry and transmission and because being a host protein it is not affected by viral mutations. However, the regulation of ACE2 remains elusive, due to the lack of appropriatein vitromodels. Cholangiocytes show one of the highest ACE2 expression levels in the body, representing an ideal platform for these studies. Here, we use cholangiocyte organoids as proof-of-principleto identify that the bile acid receptor FXR regulates ACE2 expression and SARS-CoV-2 infectionin vitro. We validate these findings in lung and gut organoids, animal models, human organs perfusedex situand patient cohorts. Aims & Methods: 1. Identify pathways controlling the transcriptional regulation of ACE2 2. Identify drugs modulating these pathways as novel prophylactic and therapeutic agents for COVID19. Organoids were propagated using established protocols. Marker expression was assessed using single-cell RNA sequencing, QPCR, and immunofluorescence. FXR binding on DNA was assessed with chromatin immunoprecipitation. SARS-CoV-2 was isolated from bronchoalveolar lavage of a COVID19 patient. Syrian golden hamsters were infected via direct inoculation and QPCR on oral swab, nasal turbinate and lung samples was used to measure SARS-CoV-2 infection. Human livers and lungs not used for transplantation were perfusedex-situusing normothermic perfusion. Nasopharyngeal swabs were used to measure ACE2 expression in nasal epithelial cells of healthy individuals taking UDCA at the standard therapeutic dose of 15 mg/kg/day. Patient registry data were compared using propensity score matching for sex, age, diabetes, NAFLD and Child- Turcotte-Pugh score. Result(s): We identified that FXR directly regulates ACE2 transcription in cholangiocyte organoids, while FXR inhibition with the approved drug ursodeoxycholic acid (UDCA), reduced ACE2 expression and SARS-CoV-2 infectionin vitro. We confirmed this mechanism in organoids from other COVID19-affected tissues, including the respiratory and intestinal systems. We validated our findingsin vivoin Syrian golden hamsters, showing that treatment with UDCA downregulates ACE2 and prevents SARS-CoV-2 infection. We confirmed that UDCA reduces ACE2 and SARS-CoV-2 infection in human lungs and livers perfusedex-situ. We performed a clinical study demonstrating that UDCA lowers ACE2 levels in the nasal epithelium of 6 healthy volunteers. Finally, we identified a correlation between UDCA and better clinical outcomes (hospitalisation, ICU admission and death) in COVID19 patients receiving UDCA for cholestatic diseases using the COVID-Hep and SECURELiver registry data. Conclusion(s): We identified FXR as a novel regulator of ACE2 expression. Using a bench-to-bedside approach combining in vitroand in vivomodels, exsituperfused human organs and clinical data we showed that FXR inhibition prevents or reduces SARS-CoV-2 infection and identified UDCA as an approved, cost-effective drug which could be repurposed for COVID19, paving the road for future clinical trials.

Brexit and labour market inequalities: potential spatial and occupational impacts

In this paper we examine the possible distributional impacts of new trade barriers associated with the new Trade and Cooperation Agreement governing relations between the UK and EU after Brexit. We use a model of labour demand that incorporates input-output links across industries, and that allows for demand substitution by firms and consumers and worker reallocation across industries. We find that workers' exposure is moderately increasing across the earnings distribution. Exposure is greater for men than for women as they are more likely to work in manufacturing industries that are relatively harder hit by new trade barriers. Looking across areas, we find that exposure to new Brexit trade barriers is uncorrelated with measures of local deprivation and the impacts of the recent Covid-19 pandemic.

Angiotensin-converting enzyme 2 (ace2) is rate-limiting for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) viral infection in beating stem cell-derived cardiomyocytes

Introduction: Cardiovascular comorbidities are a major risk factor in patients infected with SARSCoV-2. SARS-CoV-2 Spike protein binds to host cell surface ACE2 to gain entry. ACE2 is subsequently downregulated by internalisation. We hypothesise that an ACE2 knockdown system in beating human embryonic stem cell-derived cardiomyocytes (hESC-CMs) will recapitulate the downregulation of ACE2, and reduce the ability of a SARS-CoV-2 Spike protein pseudotyped virus to infect these clinically relevant cells. Method: ACE2 was knocked down (KD) with CRISPR/Cas9 in hESCs, before differentiating to hESC-CMs and sub-culturing in 96 well plates. Sanger sequencing confirmed amino acid changes. Catalytic ACE2 activity was measured by mass spectrometry in wild-type versus KD by conversion of apelin-13 to apelin-12 in hESC-CMs supernatant. ACE2 activity was also measured by fluorescent substrate assay. Pseudotyped virus infection was visualised by high content screening in ACE2 KD versus wild-type (n=4). All data are mean±SEM. Results: Sequencing revealed two substitutions at ACE2 , and three deletions at ACE2 . This reduced ACE2 catalytic activity by ∼60-70% by apelin-12 accumulation using mass spectrometry (Fig 1a), and fluorescent assay. Furthermore, KD reduced infection of hESC-CMs by pseudotyped virus to 27.3±9.6% of the cell population versus 74.8±4.7% for wild-type (Fig 1b,c). This is consistent with our previous data, showing DX600 (peptidic inhibitor of ACE2 catalytic site) significantly reduced infection of wild-type hESC-CMs to 20.5±6.5%. Conclusions: In conclusion, we generated a functional ACE2 knockdown in a beating cardiomyocyte cell model. Both the catalytic activity and the ability to bind SARS-CoV-2 Spike protein of ACE2 reduced, importantly indicating ACE2 is rate limiting for infection. We aim to use this system to further explore the cardiovascular consequences of SARS-CoV-2 infection and subsequent downregulation of ACE2.

The link between inflammation, coagulation and endothelium damage in COVID-19: Evidence from an exploratory crosssectional study

Background: Increasing evidence suggests that endothelial activation and dysfunction contribute to COVID-19 pathogenesis by altering vessel integrity, promoting pro-coagulative and inflammatory state. Aims: 1. Investigate changes in coagulation, inflammation and endothelium associated with the progression and severity of COVID-19, as well as their correlation to survival and/or occurrence of venous thromboembolic events (VTE). 2. Explore potential new biomarkers to predict COVID-19 severity. Methods: Samples were collected from COVID-19 patients after appropriate consent. Disease severity was assessed with WHO ordinal scale on day of sampling. In addition to routine haematology, biochemistry and coagulation analysis, additional analysis spanning coagulation, endothelium, platelet, inflammatory biomarkers by conventional assays and multiplex immuno-assays were undertaken. Results: Participants included 151 COVID-19 patients aged 18 years and greater, 16 healthy volunteers and 9 non-COVID-19 ICUcontrols. COVID-19 patients were categorised in 7 groups based on severity and time from symptom onset and the data also provides mortality and VTE rates (Table 1). The biomarker profile of hospitalised COVID-19 patients demonstrated an increase in plasma levels of cytokines, inflammatory, soluble endothelial cell markers and markers of coagulation activation when compared to the ambulatory group (Figure 1). Significantly higher levels of inflammatory markers (CRP, WBC, fibrinogen, serum amyloid P, alpha 1 acid glycoprotein) were observed in patients with VTE and in the non-survivors group. Interestingly, the same trend was seen for coagulation (FVIII, VWF) and fibrinolysis markers (D-dimer, TFPI, t-PA) with higher levels in the VTE and non-survivors group. In addition, higher plasma levels of endothelial markers (ICAM-1, angiopoietin, TIE-2, LYVE-1, syndecan) were observed in severe COVID-19 when compared to non-COVID-19 ICU-controls. (Figure Presented) Conclusions: Our study provides evidence of a strong, global inflammatory response in COVID-19 patients. The elevation of circulating markers suggests significant endothelial cell activation/dysfunction and a possible cause for the pro-coagulant phenotype observed in these patients.

Fxr as a new therapeutic target for COVID-19

Background: Despite recent advances, the management of COVID19 is complicated by vaccine availability, the modest efficacy of existing treatments, and the potential for viral resistance. Therefore, there is a pressing need for new prophylactic and therapeutic agents. Modifying the expression of the SARS-CoV-2 entry receptor ACE2 could prevent viral infection and limit disease progression. Here, we identify that ACE2 expression is controlled by the transcription factor farnesoid X receptor (FXR) and demonstrate that ACE2 downregulation through FXR antagonism, using approved drugs, such as ursodeoxycholic acid (UDCA), could represent a novel therapeutic strategy to complement current approaches. Methods: Primary cholangiocyte, pulmonary and intestinal organoids were propagated using established protocols. Marker expression was assessed using singlecell RNA sequencing, QPCR, immunofluorescence and flow cytometry. FXR binding on DNA was assessed with chromatin immunoprecipitation. SARS-CoV-2 was isolated from bronchoalveolar lavage of a COVID19 patient. Viral load was measured via QPCR. Human livers not used for transplantation were perfused ex-situ using the metra (OrganOx) normothermic perfusion device. Serum ACE2 activity was measured with commercial kits. Patient data from the COVID-Hep and SECURE-Liver registries were compared using propensity score matching. Results: FXR activation directly upregulated ACE2 transcription in organoids from COVID19 affected tissues, including the biliary, gastrointestinal and respiratory systems. Conversely, FXR antagonism with z-guggulsterone or UDCA, had the opposite effect. Importantly, both drugs reduced susceptibility to SARS-CoV-2 infection in lung, cholangiocyte and gut organoids. Furthermore, systemic administration of UDCA in human organs perfused ex-situ downregulated ACE2 and reduced SARS-CoV-2 infection ex-vivo. Oral UDCA rapidly reduced serum ACE2 in vivo. Registry data showed a correlation between UDCA administration and better clinical outcomes in COVID19 patients, including hospitalisation, ICU admission, mechanical ventilation and death. Conclusion: We discovered FXR as a novel therapeutic target against SARS-CoV-2 and we identified approved FXR inhibitors which could be repurposed to potentially treat COVID19, paving the road for future clinical trials to validate these results.

Fxr antagonists as new agents for COVID19

Introduction The management of COVID19 is complicated by vaccine availability, the modest efficacy of existing treatments, and the potential for viral resistance. Therefore, there is a pressing need for new prophylactic and therapeutic agents. The viral receptor ACE2 is an ideal target as it is required for SARS-CoV-2 entry in host cells. Modifying ACE2 expression could prevent infection and/or limit disease progression. Nevertheless, the mechanisms controlling ACE2 expression remain elusive. Aims To identify pathways controlling the transcriptional regulation of ACE2, and exploit them to reduce SARS-CoV-2 infection. Methods Organoids from primary biliary, intestinal and pulmonary epithelia were derived and cultured as previously described. Single-cell RNA sequencing, QPCR, immunofluorescence and flow cytometry were used to assess marker expression. Chromatin immunoprecipitation was used to assess FXR binding on DNA. Bronchoalveolar lavage SARS-CoV-2 patient isolates were used for infection experiments. Human livers not used for transplantation were connected to the metra (OrganOx) normothermic perfusion device and perfused ex-situ using therapeutic doses of UDCA for 12 hours. ACE2 activity was measured following manufacturer's instructions. Patient data from the COVID-Hep and SECURE-Liver registries were compared using propensity score matching for sex, age and Child-Turcotte-Pugh score. Results We first demonstrated that cholangiocytes are susceptible to SARS-CoV-2 infection in vivo and in organoid culture. We then used cholangiocyte organoids to identify FXR as a transcriptional regulator of ACE2. We validated our results in pulmonary and intestinal organoids, showing that ACE2 regulation by FXR represents a broad mechanism present in multiple COVID19-affected tissues. We then demonstrated that approved FXR inhibitors, such as ursodeoxycholic acid (UDCA) and z-guggulsterone (ZGG), decrease ACE2 levels and reduce viral infection in vitro in primary biliary, intestinal and pulmonary organoids. We interrogated the impact of systemic UDCA administration in human livers perfused ex-situ, demonstrating reduced ACE2 levels and SARS-CoV-2 infection. Furthermore, we showed that commencing UDCA treatment lowers ACE2 levels in primary biliary cholangitis (PBC) patients. Finally, we identified a correlation between UDCA treatment and better clinical outcome in COVID-19 patients, including hospitalisation, ICU admission, mechanical ventilation and death, using registry data. Conclusion We identified FXR as a novel master regulator of ACE2 expression. Using a bench-to-bedside approach we combined in vitro, ex-vivo and patient data to demonstrate the efficacy of ACE2 downregulation against SARS-CoV-2 infection and identified approved and inexpensive drugs (UDCA, ZGG) which could be repurposed as prophylactic and therapeutic agents against SARS-CoV-2 infection, paving the road for future clinical trials.

Frailty score before admission as risk factor for mortality of renal patients during the first wave of the COVID pandemic in London

Background: Frailty is a known predictor of mortality and poor outcomes during hospital admission. In this large renal retrospective cohort study, we investigated whether frailer COVID-19 positive renal patients had worse outcomes. Design: All SARS-Cov-2 positive renal patients aged >=18 years who presented to the emergency department at the Royal Free Hospital or at the satellite dialysis centres from 10th of March until the 10th of May 2020, with recent data on frailty, were included. The follow up was until 26th of May 2020. Age, gender, ethnicity, body mass index, chronic kidney disease stage, modality of renal replacement therapy, co-morbidities, Rockwood clinical frailty score (CFS), C reactive protein and the neutrophil-to-lymphocyte count were collected at presentation. The primary outcome was the overall mortality rate following COVID-19 diagnosis. Secondary outcomes included the need for hospital admission.