Severe COVID-19 Illness and α1-Antitrypsin Deficiency: COVID-AATD Study

Does hypersialylation compensate the functional Alpha1-AntiTrypsin (A1AT) deficiency in all critically ill patients?

Alpha-1 antitrypsin (A1AT) is the major circulating serine protease inhibitor. Hypersialylated glycoforms (HSG) are produced to boost A1AT anti-inflammatory and anti-protease properties. Their occurrence and prognostic impact outside severe COVID-19 or community-acquired pneumonia are unknown. Our aim was to clarify the occurrence of A1AT functional deficiency and HSG in patients admitted into intensive care unit (ICU) for any cause. A1AT and elastase inhibitory capacity (EIC) were measured in serum. Functional A1AT deficiency was defined by a measured EIC/calculated EIC Ratio ≤0.85. HSG were identified by isoelectrofocusing and quantified by gel densitometry. A total of 248 serum samples was analyzed, 173 from COVID-19 and 75 from non COVID-19 patients. A functional A1AT deficiency occurred 3-fold more frequently in non-COVID-19 than in COVID-19 patients: 18.7 % vs 6.9 % and was not associated with more frequent S/Z deficient alleles. Functional deficiency was also more frequent in deceased than alive patients in COVID-19 group. M0 and M1 HSG of A1AT occurred in around half of patients but the relative proportion of M1 significantly increased in deceased vs alive patients only in the non-COVID-19 group explaining the absence of worsening of the functional deficiency. In conclusion, our study shows that a functional A1AT deficiency is more frequently observed in patients admitted to the ICU for a cause unrelated to COVID-19, as well as in those with an unfavorable evolution. Among the latter, only those admitted for non-COVID-19 tried to compensate the functional deficiency by increasing the proportion of M1 HSG of A1AT.

COVID-19 in Individuals with Severe Alpha 1-Antitrypsin Deficiency

Background

The risk of coronavirus (COVID-19) can be affected by the presence of certain chronic conditions. It is unknown if individuals with severe hereditary alpha-1-antitrypsin deficiency (AATD) faced an increased risk of severe COVID-19 infection during the pandemic and if COPD in this population affected the risk of severe COVID-19 outcomes.

Aim

Our aim was to investigate COVID-19 outcomes in individuals with severe AATD and to identify if COPD was a risk factor for severe disease.

Methods

Between 2021-2023 we interviewed 863 individuals with severe AATD (phenotype PiZZ) included in the Swedish National AATD Registry. Details on COVID-19 outcomes were collected. Cox regression models were used to assess risk of mild and severe COVID-19 by presence of COPD.

Results

Of 863 subjects with severe AATD, 231 reported COVID-19 infection (208 mild and 23 severe COVID-19). Subjects with severe COVID-19 were older, had lower FEV1 values, were more likely ever-smokers and had more comorbidities compared to those with mild COVID-19. Subjects with COPD had over a 5-fold increased risk of severe COVID-19 compared to those without COPD (HR 5.43 (95% CI 1.61-18.27, p=0.006). After adjusting for potential confounders including smoking habits the risk remained significant (HR 3.72 (95% CI 1.04-13.23, p=0.043)).

Conclusion

Most patients with severe AATD exhibit mild symptoms of COVID-19 infection, managing them in the community. Patients who also have COPD are at increased risk of severe COVID-19 infection.

Special Issue "Latest Research in Post-COVID (Long COVID): Pathological and Treatment Studies of Sequelae and Complications"

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pathogen provoked the most unprecedented sanitary outbreak of the current century by causing coronavirus disease 2019 (COVID-19), which has led to approximately 775 million confirmed cases and more than 7 million deaths globally [...].

Host factors of SARS-CoV-2 in infection, pathogenesis, and long-term effects

SARS-CoV-2 is the causative virus of the devastating COVID-19 pandemic that results in an unparalleled global health and economic crisis. Despite unprecedented scientific efforts and therapeutic interventions, the fight against COVID-19 continues as the rapid emergence of different SARS-CoV-2 variants of concern and the increasing challenge of long COVID-19, raising a vast demand to understand the pathomechanisms of COVID-19 and its long-term sequelae and develop therapeutic strategies beyond the virus per se. Notably, in addition to the virus itself, the replication cycle of SARS-CoV-2 and clinical severity of COVID-19 is also governed by host factors. In this review, we therefore comprehensively overview the replication cycle and pathogenesis of SARS-CoV-2 from the perspective of host factors and host-virus interactions. We sequentially outline the pathological implications of molecular interactions between host factors and SARS-CoV-2 in multi-organ and multi-system long COVID-19, and summarize current therapeutic strategies and agents targeting host factors for treating these diseases. This knowledge would be key for the identification of new pathophysiological aspects and mechanisms, and the development of actionable therapeutic targets and strategies for tackling COVID-19 and its sequelae.

A reduced proteomic signature in critically ill Covid-19 patients determined with plasma antibody micro-array and machine learning

BACKGROUND

COVID-19 is a complex, multi-system disease with varying severity and symptoms. Identifying changes in critically ill COVID-19 patients' proteomes enables a better understanding of markers associated with susceptibility, symptoms, and treatment. We performed plasma antibody microarray and machine learning analyses to identify novel proteins of COVID-19.

METHODS

A case-control study comparing the concentration of 2000 plasma proteins in age- and sex-matched COVID-19 inpatients, non-COVID-19 sepsis controls, and healthy control subjects. Machine learning was used to identify a unique proteome signature in COVID-19 patients. Protein expression was correlated with clinically relevant variables and analyzed for temporal changes over hospitalization days 1, 3, 7, and 10. Expert-curated protein expression information was analyzed with Natural language processing (NLP) to determine organ- and cell-specific expression.

RESULTS

Machine learning identified a 28-protein model that accurately differentiated COVID-19 patients from ICU non-COVID-19 patients (accuracy = 0.89, AUC = 1.00, F1 = 0.89) and healthy controls (accuracy = 0.89, AUC = 1.00, F1 = 0.88). An optimal nine-protein model (PF4V1, NUCB1, CrkL, SerpinD1, Fen1, GATA-4, ProSAAS, PARK7, and NET1) maintained high classification ability. Specific proteins correlated with hemoglobin, coagulation factors, hypertension, and high-flow nasal cannula intervention (P < 0.01). Time-course analysis of the 28 leading proteins demonstrated no significant temporal changes within the COVID-19 cohort. NLP analysis identified multi-system expression of the key proteins, with the digestive and nervous systems being the leading systems.

CONCLUSIONS

The plasma proteome of critically ill COVID-19 patients was distinguishable from that of non-COVID-19 sepsis controls and healthy control subjects. The leading 28 proteins and their subset of 9 proteins yielded accurate classification models and are expressed in multiple organ systems. The identified COVID-19 proteomic signature helps elucidate COVID-19 pathophysiology and may guide future COVID-19 treatment development.

The Inhibition of Serine Proteases by Serpins Is Augmented by Negatively Charged Heparin: A Concise Review of Some Clinically Relevant Interactions

Serine proteases are members of a large family of hydrolytic enzymes in which a particular serine residue in the active site performs an essential role as a nucleophile, which is required for their proteolytic cleavage function. The array of functions performed by serine proteases is vast and includes, among others, the following: (i) the ability to fight infections; (ii) the activation of blood coagulation or blood clot lysis systems; (iii) the activation of digestive enzymes; and (iv) reproduction. Serine protease activity is highly regulated by multiple families of protease inhibitors, known collectively as the SERine Protease INhibitor (SERPIN). The serpins use a conformational change mechanism to inhibit proteases in an irreversible way. The unusual conformational change required for serpin function provides an elegant opportunity for allosteric regulation by the binding of cofactors, of which the most well-studied is heparin. The goal of this review is to discuss some of the clinically relevant serine protease-serpin interactions that may be enhanced by heparin or other negatively charged polysaccharides. The paired serine protease-serpin in the framework of heparin that we review includes the following: thrombin-antithrombin III, plasmin-anti-plasmin, C1 esterase/kallikrein-C1 esterase inhibitor, and furin/TMPRSS2 (serine protease Transmembrane Protease 2)-alpha-1-antitrypsin, with the latter in the context of COVID-19 and prostate cancer.

Utility of the Enhanced Liver Fibrosis score as a blood biomarker of pulmonary fibrosis secondary to SARS-CoV-2 pneumonia

INTRODUCTION

SARS-CoV-2 pneumonia can lead to several sequelae, among them, pulmonary fibrosis. The Enhanced Liver Fibrosis (ELF) score is a panel of serum markers of liver fibrosis. We aimed to describe the utility of the ELF score as a biomarker of pulmonary fibrosis secondary to COVID-19 pneumonia.

METHODS

Chest computed tomography (CT) scan, lung function tests (LFT) and blood analysis were obtained at three months after discharge. Data were analysed according to ELF scores and posteriorly divided into ELF tertiles.

RESULTS

One hundred twenty-nine patients were recruited; of these, 85.7% presented bilateral pneumonia at diagnosis of SARS-CoV2 infection. At 3 months after discharge, CT scan was available in 123 patients, 73 (59.3%) of whom presented parenchymal lung abnormalities (PLA) and LFT showed impairment in 28 (22.7%) patients. Globally, the most frequent PLA was ground glass opacities (50%), followed by bronchial thickening (26.8%), reticular pattern (19.5%), consolidation (10.5%) and air bronchogram sign (7.3%). Radiological findings were only significant in the higher tertile of ELF, with a reticular pattern as the predominant PLA (p = 0.002). Moreover, patients with both PLA and LFT impairment, presented a trend towards higher levels of ELF compared with patients with only PLA or LFT impairment, or no impairment (9.9 (0.7) vs 9.6 (0.8), 9.1 (1.1) and 9.3 (0.7); p = 0.054).

CONCLUSION

Patients with both PLA and LFT alteration at 3 months after SARS-CoV-2 pneumonia had higher ELF scores. The ELF score may be useful to identify patients with risk of fibrotic changes after SARS-CoV-2 pneumonia.

Alpha-1-antitrypsin antagonizes COVID-19: a review of the epidemiology, molecular mechanisms, and clinical evidence

Alpha-1-antitrypsin (AAT), a serine protease inhibitor (serpin), is increasingly recognized to inhibit SARS-CoV-2 infection and counter many of the pathogenic mechanisms of COVID-19. Herein, we reviewed the epidemiologic evidence, the molecular mechanisms, and the clinical evidence that support this paradigm. As background to our discussion, we first examined the basic mechanism of SARS-CoV-2 infection and contend that despite the availability of vaccines and anti-viral agents, COVID-19 remains problematic due to viral evolution. We next underscored that measures to prevent severe COVID-19 currently exists but teeters on a balance and that current treatment for severe COVID-19 remains grossly suboptimal. We then reviewed the epidemiologic and clinical evidence that AAT deficiency increases risk of COVID-19 infection and of more severe disease, and the experimental evidence that AAT inhibits cell surface transmembrane protease 2 (TMPRSS2) - a host serine protease required for SARS-CoV-2 entry into cells - and that this inhibition may be augmented by heparin. We also elaborated on the panoply of other activities of AAT (and heparin) that could mitigate severity of COVID-19. Finally, we evaluated the available clinical evidence for AAT treatment of COVID-19.