Inflammation-associated changes in lipid composition and the organization of the erythrocyte membrane

The Chemical Reactivity of Membrane Lipids

It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.

Plasma phospholipids profiling changes were associated with the therapeutic response to Roxadustat in peritoneal dialysis patients

Background: Elevated Phospholipids (PLs) and sphingolipid (SM) metabolism relates to with poor clinical status and adverse outcome of end-stage kidney disease patients undergoing peritoneal dialysis (PD). Studies have suggested that the use of hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI) (Roxadustat) is associated with altered lipid metabolism. Observing on how PLs and SMs changes after the HIF-PHI treatment in PD patients may help understand the possible effect of HIF-PHI on PD patients besides correcting of anemia. Materials and methods: Stable peritoneal dialysis (PD) patients treated with Roxadustat for over 3 months were included. Phospholipid and sphingolipid metabolism were measured before and after treatment. Results: 25 PD patients were included. Overall, phospholipid and sphingolipid metabolism showed a decreasing trend after HIF-PHI treatment. Levels of LysoPC (20:0), 1,2-dilinoleoyl-sn-glycero-3-phosphocholine [CisPC (DLPC) (18:2)], lysophosphatidylethanolamine (LysoPE) (14:0), and sphingomyelin (d18:1/17:0) (17:0) were significantly decreased (all p < 0.05). Further regression analyses confirmed the significant relationship between the increased of hemoglobin levels and the decrease in egg lyso PC: phosphatidylethanolamines (PE) (16:0-18:1), PE (16:0-18:2), PE (16:0-22:6), PE (18:0-20:4), PE (18:0-18:2), LysoPE (18:0), LysoPE (18:1), and phosphatidylcholine (PC) (18:1-18:0). Conclusion: This study demonstrated that phospholipid and sphingolipid metabolism decreased after administration of HIF-PHI and was associated with improvement of anemia.

Nomogram model for predicting frailty of patients with hematologic malignancies - A cross-sectional survey

Objective

This study aimed to develop and validate an assessment tool for predicting and mitigating the risk of frailty in patients diagnosed with hematologic malignancies.

Methods

A total of 342 patients with hematologic malignancies participated in this study, providing data on various demographics, disease-related information, daily activities, nutritional status, psychological well-being, frailty assessments, and laboratory indicators. The participants were randomly divided into training and validation groups at a 7:3 ratio. We employed Lasso regression analysis and cross-validation techniques to identify predictive factors. Subsequently, a nomogram prediction model was developed using multivariable logistic regression analysis. Discrimination ability, accuracy, and clinical utility were assessed through receiver operating characteristic (ROC) curves, C-index, calibration curves, and decision curve analysis (DCA).

Results

Seven predictors, namely disease duration of 6-12 months, disease duration exceeding 12 months, Charlson Comorbidity Index (CCI), prealbumin levels, hemoglobin levels, Generalized Anxiety Disorder-7 (GAD-7) scores, and Patient Health Questionnaire-9 (PHQ-9) scores, were identified as influential factors for frailty through Lasso regression analysis. The area under the ROC curve was 0.893 for the training set and 0.891 for the validation set. The Hosmer-Lemeshow goodness-of-fit test confirmed a good model fit. The C-index values for the training and validation sets were 0.889 and 0.811, respectively. The DCA curve illustrated a higher net benefit when using the nomogram prediction model within patients threshold probabilities ranging from 10% to 98%.

Conclusions

This study has successfully developed and validated an effective nomogram model for predicting frailty in patients diagnosed with hematologic malignancies. The model incorporates disease duration (6-12 months and>12 months), CCI, prealbumin and hemoglobin levels, GAD-7, and PHQ-9 scores as predictive variables.

A deformability-based biochip for precise label-free stratification of metastatic subtypes using deep learning

Cellular deformability is a promising biomarker for evaluating the physiological state of cells in medical applications. Microfluidics has emerged as a powerful technique for measuring cellular deformability. However, existing microfluidic-based assays for measuring cellular deformability rely heavily on image analysis, which can limit their scalability for high-throughput applications. Here, we develop a parallel constriction-based microfluidic flow cytometry device and an integrated computational framework (ATMQcD). The ATMQcD framework includes automatic training set generation, multiple object tracking, segmentation, and cellular deformability quantification. The system was validated using cancer cell lines of varying metastatic potential, achieving a classification accuracy of 92.4% for invasiveness assessment and stratifying cancer cells before and after hypoxia treatment. The ATMQcD system also demonstrated excellent performance in distinguishing cancer cells from leukocytes (accuracy = 89.5%). We developed a mechanical model based on power-law rheology to quantify stiffness, which was fitted with measured data directly. The model evaluated metastatic potentials for multiple cancer types and mixed cell populations, even under real-world clinical conditions. Our study presents a highly robust and transferable computational framework for multiobject tracking and deformation measurement tasks in microfluidics. We believe that this platform has the potential to pave the way for high-throughput analysis in clinical applications, providing a powerful tool for evaluating cellular deformability and assessing the physiological state of cells.

Anemia of inflammatory: does eiderr knowledge mean better diagnosis and treatment?

Anemia, which is a manifestation of the deterioration of patients' health and performance, is a common concomitant condition in diseases with signs of inflammation activation. This anemia - anemia of inflammation, is caused by disturbances of iron metabolism that lead to iron retention within macrophages, cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation, and a reduced erytrocyte half-life. Anemia is usually mild to moderate, normocytic and normochromic. It is characterized by low iron circulation, but normal to increased levels of stored ferritin and the hormone hepcidin. The primary therapeutic approach is the treatment of the underlying inflammatory disease. In case of failure, iron supplementation and / or treatment with erythropoietin stimulating agents may be used. Blood transfusions are just an emergency treatment for life-threatening anemia. A new treatment modalities with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors is emerging. However, their therapeutic efficacy needs to be verified and evaluated in clinical trials.

Erythrocytes Functionality in SARS-CoV-2 Infection: Potential Link with Alzheimer's Disease

Coronavirus disease 2019 (COVID-19) is a rapidly spreading acute respiratory infection caused by SARS-CoV-2. The pathogenesis of the disease remains unclear. Recently, several hypotheses have emerged to explain the mechanism of interaction between SARS-CoV-2 and erythrocytes, and its negative effect on the oxygen-transport function that depends on erythrocyte metabolism, which is responsible for hemoglobin-oxygen affinity (Hb-O2 affinity). In clinical settings, the modulators of the Hb-O2 affinity are not currently measured to assess tissue oxygenation, thereby providing inadequate evaluation of erythrocyte dysfunction in the integrated oxygen-transport system. To discover more about hypoxemia/hypoxia in COVID-19 patients, this review highlights the need for further investigation of the relationship between biochemical aberrations in erythrocytes and oxygen-transport efficiency. Furthermore, patients with severe COVID-19 experience symptoms similar to Alzheimer's, suggesting that their brains have been altered in ways that increase the likelihood of Alzheimer's. Mindful of the partly assessed role of structural, metabolic abnormalities that underlie erythrocyte dysfunction in the pathophysiology of Alzheimer's disease (AD), we further summarize the available data showing that COVID-19 neurocognitive impairments most probably share similar patterns with known mechanisms of brain dysfunctions in AD. Identification of parameters responsible for erythrocyte function that vary under SARS-CoV-2 may contribute to the search for additional components of progressive and irreversible failure in the integrated oxygen-transport system leading to tissue hypoperfusion. This is particularly relevant for the older generation who experience age-related disorders of erythrocyte metabolism and are prone to AD, and provide an opportunity for new personalized therapies to control this deadly infection.

Relationship between certain hematological parameters and risk of breast cancer

Aim: To explore the association between preoperative hemoglobin-to-red cell distribution width ratio (HRR), platelet-to-monocyte ratio or monocyte-to-high-density lipoprotein ratio and risk of breast cancer. Materials & methods: The clinical data of 226 patients with breast cancer were retrospectively analyzed and compared with 199 healthy controls by multivariate logistic regression analysis. Results: Multivariate logistic regression analysis revealed that HRR (p < 0.001) and monocyte-to-high-density lipoprotein ratio (p < 0.001) were independent predictors of breast cancer and lower HRR was associated with longer hospitalization, larger red cell distribution width value and lower hemoglobin level (p < 0.05). Conclusion: A significant association was found between HRR and clinical characteristics in breast cancer patients. Therefore, HRR is expected to become a novel and promising predictor of breast cancer.

Andrographolide exerted anti-inflammatory effects thereby reducing sex hormone synthesis in LPS-induced female rats, but had no effect on hormone production in healthy ones

Females have higher inflammatory tolerance because they have some special sex-related anti-inflammatory pathways. Andrographolide, a diterpene lactone compound from Andrographis paniculata (Burm.f.) Nees, has a powerful anti-inflammatory effect. But whether andrographolide regulates sex-related anti-inflammatory pathways in females has yet to be reported. A non-targeted metabonomics method was employed to investigate the metabolic pathways of andrographolide in LPS-induced inflammatory female rats. Substances and genes were then selected out of gender-related pathways discovered by metabonomics experiments and their quantities or expressions were evaluated. Furthermore, the effects of andrographolide on these chemicals or genes in non-inflammatory female rats were also examined in order to investigate the cascade interaction between anti-inflammatory mechanisms and metabolites. The biomarkers of 24 metabolites in plasma were identified. Following pathway enrichment analysis, these metabolic markers were clustered into glycerophosphate, glycerolipids, inositol phosphate and steroid hormone synthesis pathways. Validation experiments confirmed that andrographolide lowered post-inflammatory female sex hormones such as progesterone, estradiol, corticosterone, and testosterone rather than increasing them. Andrographolide may have these effects via inhibiting the overexpression of CYP11a1 and StAR. However, andrographolide had no effect on the expression of these two genes or the four types of hormones in non-inflamed female rats. Similarly, andrographolide decreased TNF-α, IL-6 and IL-1β production in inflammatory rats but showed no effect on these inflammatory markers in non-inflammatory rats. LPS and other inflammatory cytokines promote hormone production, which in turn will prevent increased inflammation. Therefore, it may be hypothesized that andrographolide’s reduction of inflammatory cytokine is what generates its inhibitory action on sex hormones during inflammation. By blocking the activation of inflammatory pathways, andrographolide prevented the stimulation of inflammatory factors on the production of sex hormones. It does not, however, directly inhibit or enhance the synthesis of sex hormones.

Anaemia and enhancement of coagulation are associated with severe COVID-19 infection

Coagulation disturbances are common in severe COVID-19 infection. We examined laboratory markers in COVID-19 patients during the first wave of the pandemic in Finland. We analysed a wide panel of coagulation tests (IL ACL TOP 750/500^®) from anonymously collected samples of 78 hospitalized COVID-19 patients in intensive care units (ICUs; n = 34) or medical wards (n = 44) at Helsinki University Hospital in April-May 2020. These coagulation data were supplemented with the laboratory information system results, including complete blood count and C reactive protein (CRP). Coagulation and inflammatory markers were elevated in most: FVIII in 52%, fibrinogen 77%, D-dimer 74%, CRP 94%, platelet count 37%. Anaemia was common, especially in men (73% vs. 44% in women), and overall weakly correlated with FVIII (women R² = 0.48, men R² = 0.24). ICU patients had higher fibrinogen and D-dimer levels (p < .01). Men admitted to the ICU also had higher platelet count, leukocytes and FVIII and lower haemoglobin than the non-ICU patients. None of the patients met the disseminated intravascular coagulation (DIC) criteria, but 31% had a D-dimer level of at least 1.5 mg/L. Presence of both anaemia and high D-dimer together with FVIII is independently associated with ICU admission. Antithrombin was reduced in 47% of the patients but did not distinguish severity. Overall, CRP was associated with coagulation activation. Elevated FVIII, fibrinogen and D-dimer reflected a strong inflammatory response and were characteristic of hospitalized COVID-19 patients. The patients were often anaemic, as is typical in severe inflammation, while anaemia was also associated with coagulation activity.

Physiology and Inflammation Driven Pathophysiology of Iron Homeostasis-Mechanistic Insights into Anemia of Inflammation and Its Treatment

Anemia is very common in patients with inflammatory disorders. Its prevalence is associated with severity of the underlying disease, and it negatively affects quality of life and cardio-vascular performance of patients. Anemia of inflammation (AI) is caused by disturbances of iron metabolism resulting in iron retention within macrophages, a reduced erythrocyte half-life, and cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation. AI is mostly mild to moderate, normochromic and normocytic, and characterized by low circulating iron, but normal and increased levels of the storage protein ferritin and the iron hormone hepcidin. The primary therapeutic approach for AI is treatment of the underlying inflammatory disease which mostly results in normalization of hemoglobin levels over time unless other pathologies such as vitamin deficiencies, true iron deficiency on the basis of bleeding episodes, or renal insufficiency are present. If the underlying disease and/or anemia are not resolved, iron supplementation therapy and/or treatment with erythropoietin stimulating agents may be considered whereas blood transfusions are an emergency treatment for life-threatening anemia. New treatments with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors emerge but their therapeutic efficacy for treatment of AI in ill patients needs to be evaluated in clinical trials.

Correlation Analysis of Hemoglobin-to-Red Blood Cell Distribution Width Ratio and Frailty in Elderly Patients With Coronary Heart Disease

Background: Coronary heart disease (CHD) is a common chronic disease in the elderly. Frailty can accelerate the development of CHD and lead to adverse health outcomes. Risk prediction and decision-making for frailty are crucial. The peripheral hemoglobin-to-red blood cell distribution width ratio (HRR) is a novel biomarker of inflammation. Our purpose was to explore the correlation between HRR and frailty in elderly patients with CHD.

Methods: This cross-sectional study evaluated 245 Chinese hospitalized patients with CHD. Blood parameters measured upon admission were obtained via the hospital electronic information medical record system. The Fried Frailty Phenotype Scale was used to evaluate the frailty status of the participants. The Receiver operating characteristic curve was used to determine the optimal cut-off values of HRR. We used univariate analysis to examine the potential factors affecting frailty. Kendall's tau-b grade correlation was used to analyze the correlation between HRR and frailty. The ordered logistic regression model was used to analyze the relationship between HRR and frailty.

Results: A total of 233 elderly patients with CHD were included in our study. Among the patients, 33.48% (78) were in a state of frailty. The optimal cut-off values of HRR was 9.76. The area under the curve (AUC) for HRR in the frailty patients was 0.652, exceed Hb (AUC = 0.618) and RDW (AUC = 0.650). Kendall's tau-b grade correlation analysis showed that HRR (K = −0.296, P < 0.001) was negatively correlated with frailty. The ordered logistic regression analysis determined that lower HRR was associated with frailty (P < 0.05) after adjusted for age, body mass index, number of drugs, comorbidity index, heart failure, red blood cells, albumin, total cholesterol, triglyceride, high density lipoprotein cholesterol, and low density lipoprotein cholesterol.

Conclusion: Lower HRR is an independent risk factor for frailty in elderly hospitalized patients with CHD. HRR was a more powerful prognostic indicator for frailty than either Hb or RDW alone. Clinicians should focus on timely identification of the risk of frailty in order to improve patient quality of life and to reduce the risk of complications.

The Ability of Metabolomics to Discriminate Non-Small-Cell Lung Cancer Subtypes Depends on the Stage of the Disease and the Type of Material Studied

Identification of the NSCLC subtype at an early stage is still quite sophisticated. Metabolomics analysis of tissue and plasma of NSCLC patients may indicate new, and yet unknown, metabolic pathways active in the NSCLC. Our research characterized the metabolomics profile of tissue and plasma of patients with early and advanced NSCLC stage. Samples were subjected to thorough metabolomics analyses using liquid chromatography-mass spectrometry (LC-MS) technique. Tissue and/or plasma samples from 137 NSCLC patients were analyzed. Based on the early stage tissue analysis, more than 200 metabolites differentiating adenocarcinoma (ADC) and squamous cell lung carcinoma (SCC) subtypes as well as normal tissue, were identified. Most of the identified metabolites were amino acids, fatty acids, carnitines, lysoglycerophospholipids, sphingomyelins, plasmalogens and glycerophospholipids. Moreover, metabolites related to N-acyl ethanolamine (NAE) biosynthesis, namely glycerophospho (N-acyl) ethanolamines (GP-NAE), which discriminated early-stage SCC from ADC, have also been identified. On the other hand, the analysis of plasma of chronic obstructive pulmonary disease (COPD) and NSCLC patients allowed exclusion of the metabolites related to the inflammatory state in lungs and the identification of compounds (lysoglycerophospholipids, glycerophospholipids and sphingomyelins) truly characteristic to cancer. Our results, among already known, showed novel, thus far not described, metabolites discriminating NSCLC subtypes, especially in the early stage of cancer. Moreover, the presented results also indicated the activity of new metabolic pathways in NSCLC. Further investigations on the role of NAE biosynthesis pathways in the early stage of NSCLC may reveal new prognostic and diagnostic targets.

Ibuprofen and the Phosphatidylcholine Bilayer: Membrane Water Permeability in the Presence and Absence of Cholesterol

The interactions between drugs and cell membranes can modulate the structural and physical properties of membranes. The resultant perturbations of the membrane integrity may affect the conformation of the proteins inserted within the membrane, disturbing the membrane-hosted biological functions. In this study, the droplet interface bilayer (DIB), a model cell membrane, is used to examine the effects of ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), on transbilayer water permeability, which is a fundamental membrane biophysical property. Our results indicate that the presence of neutral ibuprofen (pH 3) increases the water permeability of the lipid membranes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). When cholesterol is present with the DOPC, however, the water permeability is not influenced by addition of ibuprofen, regardless of the cholesterol content in DOPC. Given the fact that cholesterol is generally considered to impact packing in the hydrocarbon chain regions, our findings suggest that a potential competition between opposing effects of ibuprofen molecules and cholesterol on the hydrocarbon core environment of the phospholipid assembly may influence the overall water transport phenomena. Results from confocal Raman microspectroscopy and interfacial tensiometry show that ibuprofen molecules induce substantial structural and dynamic changes in the DOPC lipid bilayer. These results, demonstrating that the presence of ibuprofen increases the water permeability of pure DOPC but not that of DOPC-cholesterol mixtures, provide insight into the differential effect of a representative NSAID on heterogeneous biological membranes, depending upon the local composition and structure, results which will signal increased understanding of the gastrointestinal damage and toxicity induced by these molecules.

Red Blood Cell Dysfunction in Non-Alcoholic Fatty Liver Disease: Marker and Mediator of Molecular Mechanisms

Despite efforts to unravel the pathogenetic mechanisms of non-alcoholic fatty liver disease (NAFLD), there is still a need for approved treatments and biomarkers. Interestingly, red blood cells present alterations in their characteristics during NAFLD. The phosphatidylcholine to phosphatidylethanolamine ratio, fatty acid profile, red blood cell count and red cell distribution width reflect molecular changes that are taking place in the liver. In addition, glycosylated hemoglobin, chemokine binding and release, and phosphatidylserine exposure actively participate in NAFLD pathogenesis. In this review, we describe the neglected red blood cell dysfunction in NAFLD, with the aim to unveil potent biomarkers and therapeutic targets.

Lipidomic analysis of local inflammation models shows a specific systemic acute phase response to lipopolysaccharides

Toll-like receptors (TLR) are crucial for recognizing bacterial, viral or fungal pathogens and to orchestrate the appropriate immune response. The widely expressed TLR2 and TLR4 differentially recognize various pathogens to initiate partly overlapping immune cascades. To better understand the physiological consequences of both immune responses, we performed comparative lipidomic analyses of local paw inflammation in mice induced by the TLR2 and TLR4 agonists, zymosan and lipopolysaccharide (LPS), respectively, which are commonly used in models for inflammation and inflammatory pain. Doses for both agonists were chosen to cause mechanical hypersensitivity with identical strength and duration. Lipidomic analysis showed 5 h after LPS or zymosan injection in both models an increase of ether-phosphatidylcholines (PC O) and their corresponding lyso species with additional lipids being increased only in response to LPS. However, zymosan induced stronger immune cell recruitment and edema formation as compared to LPS. Importantly, only in LPS-induced inflammation the lipid profile in the contralateral paw was altered. Fittingly, the plasma level of various cytokines and chemokines, including IL-1β and IL-6, were significantly increased only in LPS-treated mice. Accordingly LPS induced distinct changes in the lipid profiles of ipsilateral and contralateral paws. Here, oxydized fatty acids, phosphatidylcholines and phosphatidylethanolamines were uniquely upregulated on the contralateral side. Thus, both models cause increased levels of PC O and lyso-PC O lipids at the site of inflammation pointing at a common role in inflammation. Also, LPS initiates systemic changes, which can be detected by changes in the lipid profiles.

Cholesterol and Phospholipid Distribution Pattern in the Erythrocyte Membrane of Patients with Hepatitis C and Severe Fibrosis, before and after Treatment with Direct Antiviral Agents: A pilot Study

Objectives: Hepatitis C virus requires and induces changes in liver lipidome for its life cycle. In addition, alterations in plasma and erythrocyte lipidome are observed during a range of chronic liver diseases. Methods: A total of six subjects (three males and three females) were included in our study. All subjects were HCV positive according to virus RNA detection. Erythrocyte ghosts were prepared from blood and collected upon diagnosis and also at the end of the treatment with Direct Antiviral Agents (DAA). Lipids were extracted from the erythrocyte ghosts, and cholesterol and phospholipids were analyzed by thin layer chromatography. A semi-quantitative estimation of cholesterol (CHOL), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylcholine (PC) and sphingomyelin (SM) was performed by densitometric analysis of the chromatographs. Results: After the antiviral treatment, PE percentage decreased, whereas the PC/PE and CHOL/PE ratio increased significantly. There were also other weaker differences for CHOL, PI, PS, PC and SM. Before DAA there was a very weak correlation between ALT and PC/PE ratio. In contrast, there was a steep negative correlation between these two parameters after DAA. Conclusion: Red blood cell lipid composition and especially the PC/PE ratio could be a candidate real time biological marker for inflammation resolution during hepatitis C treatment.

Cytokine Release Syndrome in COVID-19 Patients, A New Scenario for an Old Concern: The Fragile Balance between Infections and Autoimmunity

On 7 January 2020, researchers isolated and sequenced in China from patients with severe pneumonitis a novel coronavirus, then called SARS-CoV-2, which rapidly spread worldwide, becoming a global health emergency. Typical manifestations consist of flu-like symptoms such as fever, cough, fatigue, and dyspnea. However, in about 20% of patients, the infection progresses to severe interstitial pneumonia and can induce an uncontrolled host-immune response, leading to a life-threatening condition called cytokine release syndrome (CRS). CRS represents an emergency scenario of a frequent challenge, which is the complex and interwoven link between infections and autoimmunity. Indeed, treatment of CRS involves the use of both antivirals to control the underlying infection and immunosuppressive agents to dampen the aberrant pro-inflammatory response of the host. Several trials, evaluating the safety and effectiveness of immunosuppressants commonly used in rheumatic diseases, are ongoing in patients with COVID-19 and CRS, some of which are achieving promising results. However, such a use should follow a multidisciplinary approach, be accompanied by close monitoring, be tailored to patient's clinical and serological features, and be initiated at the right time to reach the best results. Autoimmune patients receiving immunosuppressants could be prone to SARS-CoV-2 infections; however, suspension of the ongoing therapy is contraindicated to avoid disease flares and a consequent increase in the infection risk.

Lipidomic profile and candidate biomarkers in septic patients

Sepsis is a severe disease with a high mortality rate. Identification and treatment in the initial hours of the disease improve outcomes. Some biomarkers like procalcitonin and C-reactive protein are used for diagnosis and to access sepsis prognosis and they can help in clinical decision-making, but none has sufficient specificity or sensitivity to be routinely employed in clinical practice. This review seeks to evaluate lipid metabolism alterations in patients with sepsis and the possibility of using the respective metabolites as biomarkers of the disease. A search of the main electronic biomedical databases was conducted for the 20-year period ending in February 2020, focused on primary research articles on biomarkers in sepsis. The keywords included sepsis, septic shock, biomarker, metabolomic, lipidomic and lysophosphatidylcoline.

. It concludes that altered lipid profiles, along with the progress of the disease should provide new insights, enabling a better understanding of the pathogenic mechanisms and making it possible to design new early diagnosis and therapeutic procedures for sepsis.

Involvement of Lactate and Pyruvate in the Anti-Inflammatory Effects Exerted by Voluntary Activation of the Sympathetic Nervous System

We recently demonstrated that the sympathetic nervous system can be voluntarily activated following a training program consisting of cold exposure, breathing exercises, and meditation. This resulted in profound attenuation of the systemic inflammatory response elicited by lipopolysaccharide (LPS) administration. Herein, we assessed whether this training program affects the plasma metabolome and if these changes are linked to the immunomodulatory effects observed. A total of 224 metabolites were identified in plasma obtained from 24 healthy male volunteers at six timepoints, of which 98 were significantly altered following LPS administration. Effects of the training program were most prominent shortly after initiation of the acquired breathing exercises but prior to LPS administration, and point towards increased activation of the Cori cycle. Elevated concentrations of lactate and pyruvate in trained individuals correlated with enhanced levels of anti-inflammatory interleukin (IL)-10. In vitro validation experiments revealed that co-incubation with lactate and pyruvate enhances IL-10 production and attenuates the release of pro-inflammatory IL-1β and IL-6 by LPS-stimulated leukocytes. Our results demonstrate that practicing the breathing exercises acquired during the training program results in increased activity of the Cori cycle. Furthermore, this work uncovers an important role of lactate and pyruvate in the anti-inflammatory phenotype observed in trained subjects.

Vesiculation of Red Blood Cells in the Blood Bank: A Multi-Omics Approach towards Identification of Causes and Consequences

Microvesicle generation is an integral part of the aging process of red blood cells in vivo and in vitro. Extensive vesiculation impairs function and survival of red blood cells after transfusion, and microvesicles contribute to transfusion reactions. The triggers and mechanisms of microvesicle generation are largely unknown. In this study, we combined morphological, immunochemical, proteomic, lipidomic, and metabolomic analyses to obtain an integrated understanding of the mechanisms underlying microvesicle generation during the storage of red blood cell concentrates. Our data indicate that changes in membrane organization, triggered by altered protein conformation, constitute the main mechanism of vesiculation, and precede changes in lipid organization. The resulting selective accumulation of membrane components in microvesicles is accompanied by the recruitment of plasma proteins involved in inflammation and coagulation. Our data may serve as a basis for further dissection of the fundamental mechanisms of red blood cell aging and vesiculation, for identifying the cause-effect relationship between blood bank storage and transfusion complications, and for assessing the role of microvesicles in pathologies affecting red blood cells.

Comparison of Erythrocyte Membrane Lipid Profiles between NAFLD Patients with or without Hyperlipidemia

Nonalcoholic fatty liver disease (NAFLD) and hyperlipidemia (HL) are common metabolic disorders due to overnutrition and obesity. NAFLD is often associated with hyperlipidemia. The aim of this study was to identify and compare the erythrocyte membrane lipids profile in NAFLD patients with or without HL. Methods. A total of 112 subjects (with similar age and body mass index) were divided into four groups: (1) normal controls, (2) NAFLD alone, (3) HL alone, and (4) NAFLD combined with HL (NAFLD + HL). Lipid was extracted from the erythrocyte membrane, and lipid profiles of subjects were analyzed by liquid chromatography mass spectrometry (LC-MS). Results. Data sets from 103 subjects were adopted for lipidomic analysis. Significant changes of lipid species were observed in patient groups, especially in the HL group and NAFLD + HL group. The HL group showed increased level of most lipid species, and decreased level of most lipid species was observed in the NAFLD + HL group. The weight percent of myristic acid, stearic acid, erucic acid, and docosahexaenoic acid also showed distinct variation between different groups. Conclusions. NAFLD, HL, and NAFLD + HL all had an impact on lipid profiling of the erythrocyte membrane. The influence of NAFLD alone is less important compared with HL. Some lipids should be highlighted because of their specific role in cell function and systemic metabolism.

Insight into erythrocyte phospholipid molecular flux in healthy humans and in patients with acute respiratory distress syndrome

Although the distribution of cellular membrane phospholipid composition is well characterised in human erythrocytes, in-vivo turnover and dynamic flux of phospholipids between plasma and erythrocytes in physiological and in particular during disease states are mostly unknown. Erythrocyte mass primarily consisted of lipids and phosphatidylcholine (PC) contributes to the significant proportion of phospholipid membrane composition. Esterified membrane PC can be utilised during pathological processes to generate pro and anti-inflammatory lipid mediators, which can contribute to the pathogenesis of acute respiratory distress syndrome (ARDS). In this study, utilising isotope labelling of choline and analytical methods with electrospray mass spectrometry (ESI-MS/MS), we characterised individual molecular composition and dynamic exchange of PC, sphingomyelins (SM) and lysophosphatidylcholines (LPC) between plasma and erythrocytes. In ARDS patients, there were significant alterations in PC molecular composition, coupled with a continuous loss of arachidonoyl-PC species over time. Infusion of methyl-D9-choline chloride resulted in enrichment of labelled choline into plasma PC and LPC via CDP-choline pathway with subsequent incorporation into erythrocyte PC. As expected, erythrocyte methyl-D9 PC enrichment is much slower than plasma. Patients had much faster and higher fractional enrichment of all PC and LPC molecules suggesting increased flux between plasma and erythrocytes. There was a particular pattern of incorporation, where the arachidonoyl-PC species achieved equilibrium with plasma rapidly and retained highest concentrations of enrichment compared to the other PC species. Increased enrichment of arachidonoyl-PC coupled with virtually no increase or depletion of its concentrations suggests the possibility of substrate donation for other cell types for the participation of eicosanoid biosynthesis during inflammatory conditions like ARDS. In summary, this study revealed an alerted pattern erythrocyte molecular phospholipid composition and flux in patients with acute respiratory distress syndrome and the pathological consequences of these changes needs further exploration.

Inflammatory anemia-associated parameters are related to 28-day mortality in patients with sepsis admitted to the ICU: a preliminary observational study

Background

Anemia is one of the most common complications of sepsis. Sepsis-related anemia is associated mainly with inflammation. We aimed to observe the changes in the inflammatory anemia-associated parameters of patients with sepsis in the early stage of intensive care unit (ICU) admission and to evaluate their association with 28-day mortality.

Methods

A total of 198 patients with sepsis were divided into survivor (n = 110) and non-survivor (n = 88) groups on the basis of 28-day survival. Healthy volunteers (n = 20) were enrolled as a control group. Plasma levels of iron, ferritin, erythropoietin (EPO), soluble transferrin receptor (sTfR), hepcidin, interleukin-6 (IL-6), hemoglobin and the red blood cell distribution width (RDW) were measured on days 1, 3 and 7 of ICU admission. Clinical data and laboratory findings were collected, and the Sequential Organ Failure Assessment (SOFA) score was calculated.

Results

Patients with sepsis showed significant decreases in hemoglobin, plasma iron and sTfR/log ferritin and significant increases in plasma EPO, sTfR, hepcidin, ferritin and IL-6 on days 1, 3 and 7 of ICU admission compared with healthy volunteers. Hemoglobin was correlated negatively with plasma IL-6 and hepcidin. In patients with sepsis, non-survivors had significantly lower plasma iron, EPO and sTfR/log ferritin, but higher plasma hepcidin, ferritin and IL-6 than survivors on days 1, 3 and 7 of ICU admission. Plasma EPO, hepcidin, ferritin, IL-6, sTfR/log ferritin, the RDW and SOFA score were associated significantly with 28-day mortality but to a varying extent. In particular, in predicting 28-day mortality, plasma hepcidin had an area under the receiver operating curve of 0.808 and 87.3% specificity, which was the highest among the inflammatory anemia-associated parameters tested.

Conclusions

Inflammatory anemia-associated parameters changed significantly in patients with sepsis in the first week of ICU admission. Plasma EPO, hepcidin, ferritin, IL-6, sTfR/log ferritin, the RDW and SOFA score were associated significantly with 28-day mortality. Plasma hepcidin might have a superior predictive value, with high specificity, compared with other inflammatory anemia-associated parameters for 28-day mortality of sepsis patients in the ICU.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0542-7) contains supplementary material, which is available to authorized users.

Multistep Interactions between Ibuprofen and Lipid Membranes

Ibuprofen (IBU) interacts with phosphatidylcholine membranes in three distinct steps as a function of concentration. In a first step (<10 μM), IBU electrostatically adsorbs to the lipid headgroups and gradually decreases the interfacial potential. This first step helps to facilitate the second step (10-300 μM), in which hydrophobic insertion of the drug occurs. The second step disrupts the packing of the lipid acyl chains and expands the area per lipid. In a final step, above 300 μM IBU, the lipid membrane begins to solubilize, resulting in a detergent-like effect. The results described herein were obtained by a combination of fluorescence binding assays, vibrational sum frequency spectroscopy, and Langmuir monolayer compression experiments. By introducing trimethylammonium-propane, phosphatidylglycerol, and phosphatidylethanolamine lipids as well as cholesterol, we demonstrated that both the chemistry of the lipid headgroups and the packing of lipid acyl chains can substantially influence the interactions between IBU and the membranes. Moreover, different membrane chemistries can alter particular steps in the binding interaction.

Disturbed Red Blood Cell Structure and Function: An Exploration of the Role of Red Blood Cells in Neurodegeneration

The structure of red blood cells is affected by many inborn and acquired factors, but in most cases this does not seem to affect their function or survival in physiological conditions. Often, functional deficits become apparent only when they are subjected to biochemical or mechanical stress in vitro, or to pathological conditions in vivo. Our data on the misshapen red blood cells of patients with neuroacanthocytosis illustrate this general mechanism: an abnormal morphology is associated with an increase in the susceptibility of red blood cells to osmotic and mechanical stress, and alters their rheological properties. The underlying mutations may not only affect red cell function, but also render neurons in specific brain areas more susceptible to a concomitant reduction in oxygen supply. Through this mechanism, an increased susceptibility of already compromised red blood cells to physiological stress conditions may constitute an additional risk factor in vulnerable individuals. Also, susceptibility may be induced or enhanced by systemic pathological conditions such as inflammation. An exploration of the literature suggests that disturbed red blood cell function may play a role in the pathophysiology of various neurodegenerative diseases. Therefore, interventions that reduce the susceptibility of red blood cells to physiological and pathological stress may reduce the extent or progress of neurodegeneration.

Red Blood Cell Homeostasis: Mechanisms and Effects of Microvesicle Generation in Health and Disease

Red blood cells (RBCs) generate microvesicles to remove damaged cell constituents such as oxidized hemoglobin and damaged membrane constituents, and thereby prolong their lifespan. Damage to hemoglobin, in combination with altered phosphorylation of membrane proteins such as band 3, lead to a weakening of the binding between the lipid bilayer and the cytoskeleton, and thereby to membrane budding and microparticle shedding. Microvesicle generation is disturbed in patients with RBC-centered diseases, such as sickle cell disease, glucose 6-phosphate dehydrogenase deficiency, spherocytosis or malaria. A disturbance of the membrane-cytoskeleton interaction is likely to be the main underlying mechanism, as is supported by data obtained from RBCs stored in blood bank conditions. A detailed proteomic, lipidomic and immunogenic comparison of microvesicles derived from different sources is essential in the identification of the processes that trigger vesicle generation. The contribution of RBC-derived microvesicles to inflammation, thrombosis and autoimmune reactions emphasizes the need for a better understanding of the mechanisms and consequences of microvesicle generation.

Lipidomic Profiling of Plasma and Erythrocytes From Septic Patients Reveals Potential Biomarker Candidates

Background

Sepsis remains the primary cause of death from infection, despite advances in modern medicine. The identification of reliable diagnostic biomarkers for the early detection of this disease is critical and may reduce the mortality rate as it could allow early treatment. The purpose of this study was to describe the changes in the plasma and red cells blood lipidome profiling of patients diagnosed with sepsis and septic shock with the aim to identify potentially useful metabolic markers.

Methods

Lipids from plasma and erythrocytes from septic patients (n = 20) and healthy controls (n = 20) were evaluated by electrospray ionization quadrupole time-of-flight mass spectrometry, and the fatty acid composition of the phospholipids fraction of erythrocytes was determined by gas chromatography. The data were treated with multivariate data analysis, including principal component analysis and (orthogonal) partial least squares discriminant analysis.

Results

Potential biomarkers including lysophosphatidylcholines (lyso-PCs) and sphingomyelin (SMs) with specific fatty acid chains were identified. Both Lyso-PCs and SMs were downregulated, whereas the saturated and unsaturated phosphatidylcholines (PCs) were upregulated in the plasma and erythrocytes of septic patients. An increase in oleic acid (C18:1 n-9) accompanied by a decrease in the unsaturation index as well as in the levels on n-3 polyunsaturated fatty acids was observed in erythrocytes phospholipids patients as compared with healthy controls.

Conclusions

These results suggest that lipidome profiling has great potential in discovering potential clinical biomarkers for sepsis and helping to understand its underlying mechanisms.

Microcirculation and red cell transfusion in patients with sepsis

Early identification of sepsis followed by diagnostic blood cultures and prompt administration of appropriate intravenous antibiotics covering all likely pathogen remains the corner stone in the initial management of sepsis. Source control, obtained by harvesting microbiological cultures and removal or drainage of the infected foci, is mandatory. However, optimization of hemodynamically unstable patients including volume support supplemented with vasopressor, inotropic and transfusion of red blood cells (RBCs) in case of persistent hypoperfusion have the potential to reduce morbidity and mortality. Given the imbalance between the ability of the cardiovascular system to deliver enough oxygen to meet the oxygen demand, transfusion of RBCs should theoretically provide the ideal solution to the challenge. However, both changes in the septic patients' RBCs induced by endogenous factors as well as the storage lesion affecting transfused RBCs have negative effects on the microcirculation. RBC morphology, distribution of fatty acids on the membrane surface, RBC deformability needed for capillary circulation and the nitrogen oxide (NO) signaling systems are involved. Although these deteriorating effects develop during storage, transfusion of fresh RBCs has not proven to be beneficial, possibly due to limitations of the studies performed. Until better evidence exists, transfusion guidelines recommend a restrictive strategy of RBC transfusion i.e. transfuse when hemoglobin (Hb)<7g/dL in septic patients.

Hyperferritinemia and inflammation

Understanding of ferritin biology has traditionally centered on its role in iron storage and homeostasis, with low ferritin levels indicative of deficiency and high levels indicative of primary or secondary hemochromatosis. However, further work has shown that iron, redox biology and inflammation are inexorably linked. During infection, increased ferritin levels represent an important host defense mechanism that deprives bacterial growth of iron and protects immune cell function. It may also be protective, limiting the production of free radicals and mediating immunomodulation. Additionally, hyperferritinemia is a key acute-phase reactants, used by clinicians as an indication for therapeutic intervention, aimed at controlling inflammation in high-risk patients. One school of thought maintains that hyperferritinemia is an 'innocent bystander' biomarker of uncontrolled inflammation that can be used to gauge effectiveness of intervention. Other schools of thought maintain that ferritin induction could be a protective negative regulatory loop. Others maintain that ferritin is a key mediator of immune dysregulation, especially in extreme hyperferritinemia, via direct immune-suppressive and pro-inflammatory effects. There is a clear need for further investigation of the role of ferritin in uncontrolled inflammatory conditions both as a biomarker and mediator of disease because its occurrence identifies patients with high mortality risk and its resolution predicts their improved survival.

Anemia of Inflammation: A Review

Impaired iron homeostasis and the suppressive effects of proinflammatory cytokines on erythropoiesis, together with alterations of the erythrocyte membrane that impair its survival, cause anemia of inflammation. Recent epidemiologic studies have connected inflammatory anemia with critical illness, obesity, aging, kidney failure, cancer, chronic infection, and autoimmune disease. The proinflammatory cytokine, interleukin-6, the iron regulatory hormone, hepcidin, and the iron exporter, ferroportin, interact to cause iron sequestration in the setting of inflammation. Although severe anemia is associated with adverse outcomes in critical illness, experimental models suggest that iron sequestration is part of a natural defense against pathogens.

The Proteome of the Red Blood Cell: An Auspicious Source of New Insights into Membrane-Centered Regulation of Homeostasis

During the past decade, the hand-in-hand development of biotechnology and bioinformatics has enabled a view of the function of the red blood cell that surpasses the supply of oxygen and removal of carbon dioxide. Comparative proteomic inventories have yielded new clues to the processes that regulate membrane-cytoskeleton interactions in health and disease, and to the ways by which red blood cells communicate with their environment. In addition, proteomic data have revealed the possibility that many, hitherto unsuspected, metabolic processes are active in the red blood cell cytoplasm. Recent metabolomic studies have confirmed and expanded this notion. Taken together, the presently available data point towards the red blood cell membrane as the hub at which all regulatory processes come together. Thus, alterations in the association of regulatory proteins with the cell membrane may be a sine qua non for the functional relevance of any postulated molecular mechanism. From this perspective, comparative proteomics centered on the red blood cell membrane constitute a powerful tool for the identification and elucidation of the physiologically and pathologically relevant pathways that regulate red blood cell homeostasis. Additionally, this perspective provides a focus for the interpretation of metabolomic studies, especially in the development of biomarkers in the blood.