Alteration in Redox Status and Lipoprotein Profile in COVID-19 Patients with Mild, Moderate, and Severe Pneumonia

Oxidative stress indexes as biomarkers of the severity in COVID-19 patients

Background: SARS-CoV-2 causes a global pandemic, with severe and critically ill COVID-19 patients often experiencing poor prognoses. Severe infection with SARS-CoV-2 is associated with oxidative stress (OS) and inflammation. Detecting markers of macromolecular damage caused by OS may provide valuable insights into disease progression. Methods: This study included 187 patients with laboratory-confirmed SARS-CoV-2 infection, categorized into non-severe, severe, and critically ill COVID-19 groups. We monitored the changes in serum indexes such as oxidized low-density lipoprotein (OxLDL), OxLDL/LDL-C ratio, advanced oxidation protein products (AOPP), 3-nitrotyrosine (3-NT), 8-hydroxydeoxyguanosine (8-OHdG), lipoprotein-associated phospholipase A2 (Lp-PLA2) and thromboxane B2 (TXB2) in patients with different clinical types. Results: 48 non-severe patients, 90 severe patients, and 49 critically ill patients were enrolled. Compared with the non-severe group, OxLDL level and OxLDL/LDL-C ratio were increased in severe COVID-19 patients and critically ill COVID-19 patients, while 3-NT and TXB2 concentrations were lower in critically ill COVID-19 patients. Critically ill COVID-19 patients also exhibited lower concentrations of Lp-PLA2 and a higher OxLDL/LDL-C ratio compared to severe COVID-19 patients. No significant differences were observed in AOPP and 8-OHdG concentrations. Spearman's correlation analysis revealed that CRP was associated with OxLDL, OxLDL/LDL-C ratio, AOPP, 3-NT, TXB2, and Lp-PLA2 (P <0.05). OxLDL was identified as an independent risk factor for progression from non-severe to severe/critically ill COVID-19. OxLDL and OxLDL/LDL-C ratio demonstrated good discriminatory value between non-severe and severe/critically ill COVID-19, with the OxLDL/LDL-C ratio also distinguishing between severe and critically ill patients. Conclusion: Patients with severe and critically ill COVID-19 exhibit elevated levels of oxidative damage to lipoproteins. OxLDL and the OxLDL/LDL-C ratio can serve as biomarkers for assessing disease severity in COVID-19 patients.

Differential analysis of lipoprotein and glycoprotein profiles in bacterial infections and COVID-19 using proton nuclear magnetic resonance and machine learning

Background

We scrutinized variations in the proton nuclear magnetic resonance (1H NMR) lipoprotein and glycoprotein profiles among hospitalized individuals with infectious diseases.

Methods

We obtained sera from 124 patients with COVID-19, 50 patients with catheter-related bacterial infections, and 50 healthy volunteers. Results were interpreted using machine learning.

Results

COVID-19 patients had bigger and more abundant VLDL particles than the control group and higher VLDL-cholesterol and VLDL-triglyceride concentrations. Patients with bacterial infections showed similar trends, but differences often did not reach statistical significance. Both types of patients showed lower LDL-cholesterol concentrations than the controls. LDL were larger, and the number of particles was lower than that of the healthy individuals. HDL particles had decreased cholesterol and increased triglycerides. Small particles were reduced. Glycoproteins were increased in both groups of patients. All these alterations were more pronounced in COVID-19 patients than those with bacterial infections. The diagnostic accuracy of these profiles exceeded 90 % when distinguishing between healthy individuals and patients, and 85 % when differentiating between the two patient groups.

Conclusion

Our findings highlight the potential of 1H NMR analysis for lipoproteins and glycoproteins as infection biomarkers. Additionally, they reveal differences between viral and bacterial infections, shedding light on an area with promising clinical significance.

Association between serum levels of GDF-15, suPAR, PIVKA-II, sdLDL and clinical outcomes in hospitalized COVID-19 patients

To quantify the circulating levels of novel serum biomarkers including GDF-15, PIVKA-II, sdLDL, suPAR, and of CRP in hospitalized COVID-19 patients compared with healthy subjects, and to evaluate their association(s) with outcomes in COVID-19. We considered patients with confirmed COVID-19, hospitalized in an Internal Medicine ward. The clinical characteristics were collected, including the number and type of comorbidities. Serum levels of GDF-15, PIVKA-II, suPAR, sdLDL, as well as CRP were measured. As outcomes, we considered Intensive Care Unit (ICU) transfer or death, as well as the length of stay (days) and in-hospital complications. Data were statistically analyzed, as appropriate, and a p value < 0.05 was considered significant. Ninety-three patients and 20 healthy controls were enrolled. COVID-19 patients vs. controls showed higher median levels of GDF-15 (p < 0.0001), PIVKA-II (p < 0.0001) and sdLDL (p = 0.0002), whereas no difference was observed for suPAR. In COVID-19 patients, the most frequent comorbidities were arterial hypertension (62.4%) and cardiovascular disease (30.1%). GDF-15 levels positively correlated with age (r = 0.433, p < 0.0001), and this correlation was confirmed for suPAR (r = 0.308, p = 0.003) and CRP (Rho = 0.40 p < 0.0001), but not for PIVKA-II and sdLDL. Higher GDF-15 levels were associated with a higher number of comorbidities (p = 0.021). The median length of stay was 22 (15; 30) days. During hospitalization, 15 patients (16%) were ICU transferred, and 6 (6.45%) died. GDF-15 serum levels correlated with the length of stay (rho = 0.27 p = 0.010), and were associated with ICU transfer or death (p = 0.003), as well as PIVKA-II (p = 0.038) and CRP (p < 0.001). Moreover, higher GDF-15 and PIVKA-II serum levels were associated with infectious complications (p = 0.008 and p = 0.017, respectively). In this cohort of hospitalized COVID-19 patients, novel inflammatory biomarkers, including GDF-15, suPAR and PIVKA II were associated with some patient's clinical characteristics, complications, and poor outcomes.

HDL-based therapeutics: A promising frontier in combating viral and bacterial infections

Low levels of high-density lipoprotein (HDL) and impaired HDL functionality have been consistently associated with increased susceptibility to infection and its serious consequences. This has been attributed to the critical role of HDL in maintaining cellular lipid homeostasis, which is essential for the proper functioning of immune and structural cells. HDL, a multifunctional particle, exerts pleiotropic effects in host defense against pathogens. It functions as a natural nanoparticle, capable of sequestering and neutralizing potentially harmful substances like bacterial lipopolysaccharides. HDL possesses antiviral activity, preventing viruses from entering or fusing with host cells, thereby halting their replication cycle. Understanding the complex relationship between HDL and the immune system may reveal innovative targets for developing new treatments to combat infectious diseases and improve patient outcomes. This review aims to emphasize the role of HDL in influencing the course of bacterial and viral infections and its and its therapeutic potential.

Oxidative Stress, Atherogenic Dyslipidemia, and Cardiovascular Risk

Oxidative stress is the consequence of an overproduction of reactive oxygen species (ROS) that exceeds the antioxidant defense mechanisms. Increased levels of ROS contribute to the development of cardiovascular disorders through oxidative damage to macromolecules, particularly by oxidation of plasma lipoproteins. One of the most prominent features of atherogenic dyslipidemia is plasma accumulation of small dense LDL (sdLDL) particles, characterized by an increased susceptibility to oxidation. Indeed, a considerable and diverse body of evidence from animal models and epidemiological studies was generated supporting oxidative modification of sdLDL particles as the earliest event in atherogenesis. Lipid peroxidation of LDL particles results in the formation of various bioactive species that contribute to the atherosclerotic process through different pathophysiological mechanisms, including foam cell formation, direct detrimental effects, and receptor-mediated activation of pro-inflammatory signaling pathways. In this paper, we will discuss recent data on the pathophysiological role of oxidative stress and atherogenic dyslipidemia and their interplay in the development of atherosclerosis. In addition, a special focus will be placed on the clinical applicability of novel, promising biomarkers of these processes.

Circulating and Urinary Concentrations of Malondialdehyde in Aging Humans in Health and Disease: Review and Discussion

(1) Background: Malondialdehyde (MDA) is a major and stable product of oxidative stress. MDA circulates in the blood and is excreted in the urine in its free and conjugated forms, notably with L-lysine and L-serine. MDA is the most frequently measured biomarker of oxidative stress, namely lipid peroxidation. Oxidative stress is generally assumed to be associated with disease and to increase with age. Here, we review and discuss the literature concerning circulating and excretory MDA as a biomarker of lipid peroxidation in aging subjects with regard to health and disease, such as kidney disease, erectile dysfunction, and COVID-19. (2) Methods: Scientific articles, notably those reporting on circulating (plasma, serum) and urinary MDA, which concern health and disease, and which appeared in PubMed were considered; they formed the basis for evaluating the potential increase in oxidative stress, particularly lipid peroxidation, as humans age. (3) Results and Conclusions: The results reported in the literature thus far are contradictory. The articles considered in the present study are not supportive of the general view that oxidative stress increases with aging. Many functions of several organs, including the filtration efficiency of the kidneys, are physiologically reduced in men and women as they age. This effect is likely to result in the apparent "accumulation" of biomarkers of oxidative stress, concomitantly with the "accumulation" of biomarkers of an organ's function, such as creatinine. How free and conjugated MDA forms are transported in various organs (including the brain) and how they are excreted in the urine via the kidney is not known, and investigating these questions should be the objective of forthcoming studies. The age- and gender-related increase in circulating creatinine might be a useful factor to be taken into consideration when investigating oxidative stress and aging.

Obesity and Dyslipidemia: A Review of Current Evidence

PURPOSE OF REVIEW

Obesity is accompanied by atherogenic dyslipidemia, a specific lipid disorder characterized by both quantitative and qualitative changes of plasma lipoproteins. The main alterations in the lipid profile include hypertriglyceridemia, reduced high-density lipoprotein (HDL) cholesterol level, and elevated small dense low-density lipoprotein (LDL) particles. Epidemiological data show that obesity is more common in women and is a frequent risk factor for reproductive disorders, metabolic complications in pregnancy, and cardiometabolic disease later in life. The aim of this narrative review is to discuss recent advances in the research of dyslipidemia in obesity, with an emphasis on female-specific disorders and cardiometabolic risk.

RECENT FINDINGS

The focus of current research on dyslipidemia in obesity is moving toward structurally and functionally modified plasma lipoproteins. Special attention is paid to the pro-atherogenic role of triglyceride-rich lipoproteins and their remnants. Introduction of advanced analytical techniques enabled identification of novel lipid biomarkers with potential clinical applications. In particular, proteomic and lipidomic studies have provided significant progress in the comprehensive research of HDL's alterations in obesity. Obesity-related dyslipidemia is a widespread metabolic disturbance in polycystic ovary syndrome patients and high-risk pregnancies, but is seldom evaluated with respect to its impact on future cardiometabolic health. Obesity and associated cardiometabolic diseases require a more depth insight into the quality of lipoprotein particles. Further application of omics-based techniques would enable a more comprehensive evaluation of dyslipidemia in order to reduce an excessive cardiovascular risk attributable to increased body weight. However, more studies on obesity-related female reproductive disorders are needed for this approach to be adopted in daily clinical practice.

CD36 mediates SARS-CoV-2-envelope-protein-induced platelet activation and thrombosis

Aberrant coagulation and thrombosis are associated with severe COVID-19 post-SARS-CoV-2 infection, yet the underlying mechanism remains obscure. Here we show that serum levels of SARS-CoV-2 envelope (E) protein are associated with coagulation disorders of COVID-19 patients, and intravenous administration of the E protein is able to potentiate thrombosis in mice. Through protein pull-down and mass spectrometry, we find that CD36, a transmembrane glycoprotein, directly binds with E protein and mediates hyperactivation of human and mouse platelets through the p38 MAPK-NF-κB signaling pathway. Conversely, the pharmacological blockade of CD36 or p38 notably attenuates human platelet activation induced by the E protein. Similarly, the genetic deficiency of CD36, as well as the pharmacological inhibition of p38 in mice, significantly diminishes E protein-induced platelet activation and thrombotic events. Together, our study reveals a critical role for the CD36-p38 axis in E protein-induced platelet hyperactivity, which could serve as an actionable target for developing therapies against aberrant thrombotic events related to the severity and mortality of COVID-19.

The bidirectional interaction of COVID-19 infections and lipoproteins

COVID-19 infections decrease total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I, A-II, and B levels while triglyceride levels may be increased or inappropriately normal for the poor nutritional status. The degree of reduction in total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I are predictive of mortality. With recovery lipid/lipoprotein levels return towards pre-infection levels and studies have even suggested an increased risk of dyslipidemia post-COVID-19 infection. The potential mechanisms for these changes in lipid and lipoprotein levels are discussed. Decreased HDL-C and apolipoprotein A-I levels measured many years prior to COVID-19 infections are associated with an increased risk of severe COVID-19 infections while LDL-C, apolipoprotein B, Lp (a), and triglyceride levels were not consistently associated with an increased risk. Finally, data suggest that omega-3-fatty acids and PCSK9 inhibitors may reduce the severity of COVID-19 infections. Thus, COVID-19 infections alter lipid/lipoprotein levels and HDL-C levels may affect the risk of developing COVID-19 infections.