Neopterin, Inflammation, and Oxidative Stress: What Could We Be Missing?

Serum neopterin and orexin-A levels in different stages of diabetic retinopathy

CLINICAL RELEVANCE

Retinopathy is one of the most common microvascular complications of diabetes mellitus and is the leading cause of vision loss in the working middle-aged population.

BACKGROUND

This study aimed to investigate the value of neopterin and orexin-A levels in patients with diabetes mellitus with different stages of diabetic retinopathy and without diabetic retinopathy and to compare those findings with results from healthy individuals without diabetes mellitus.

METHODS

In total, 65 patients with type 2 diabetes mellitus and 22 healthy individuals without diabetes mellitus were enrolled in this prospective study. The participants were separated into four subgroups. The first subgroup included 25 patients without diabetic retinopathy, the second subgroup included 20 patients non-proliferative diabetic retinopathy, the third subgroup included 20 patients with proliferative diabetic retinopathy, and the fourth subgroup included 22 healthy individuals without diabetes mellitus as controls. Serum neopterin and orexin-A levels were analysed and compared among the groups.

RESULTS

The age and gender of the participants between the four subgroups were not statistically significantly different (p > 0.05). The mean neopterin levels were significantly higher in patients included in the diabetes mellitus subgroups compared with the controls (p < 0.001). Neopterin levels significantly increased as diabetic retinopathy progressed within the diabetes mellitus subgroups. Mean orexin-A levels were significantly lower in the diabetes mellitus subgroups compared with the controls (p < 0.001); however, orexin-A levels were not significantly different within the diabetes mellitus subgroups (p > 0.05).

CONCLUSION

Patients with diabetes mellitus have higher serum neopterin and lower serum orexin-A levels compared with healthy individuals without diabetes mellitus. Moreover, serum neopterin levels increase with progression of diabetic retinopathy.

Neopterin, 7,8-dihydroneopterin, total neopterin levels and their ratio in periodontitis: New dilemma

OBJECTIVE

Determine the saliva and serum levels of neopterin (NP) and 7,8-dihydroneopterin (7,8NP) in periodontitis patients and to reveal the relationship of these data with clinical periodontal parameters.

MATERIALS AND METHODS

Twenty-three patients with stage III/grade B periodontitis and 23 periodontally healthy individuals were included. Clinical periodontal measurements were recorded (plaque index, pocket depth, clinical attachment loss & bleeding on probing). Saliva and serum levels of NP and 7,8NP were analyzed by high-performance liquid chromatography.

RESULTS

Saliva NP, 7,8NP and Total Neopterin (TNP) levels were significantly elevated in the periodontitis than the control group (p < 0.001).ROC analyses of saliva NP, 7,8NP and TNP yielded areas under the curves of 0.873-0.938 for discriminating periodontitis from health, and saliva TNP was found the most accurate biomarker (AUC = 0.938).There was no significant difference among the periodontitis and control groups for saliva TNP/NP and TNP/7,8NP ratios and serum NP, 7,8NP and TNP levels (p > 0.05).

CONCLUSION

Increased saliva TNP, NP and 7,8NP levels in periodontitis may suggest these biomarkers are regulating immune activation and oxidative stress mechanism in periodontal inflammation. Additionally, together with these results, equivalence of the TNP/NP ratio in intergroups may suggest that the effects of immune activation and oxidative stress mechanisms are equal in the periodontitis.

Exploring oxidative stress, immunological and metabolic biomarkers in dairy cows with postpartum pyometra

Pyometra is a prevalent and severe infectious disease that affects the reproductive systems of cattle worldwide. This study's main goal was to investigate the biomarkers for oxidative stress (OS), adiponectin, leptin and neopterin (NPT) in cows suffering from postpartum pyometra. The study also aimed to determine which bacteria were most commonly implicated in the development of the disease. A total of 74 cows with pyometra were examined and compared to a control group of healthy cows (n = 20). In comparison to the healthy control and post-treatment groups, the pyometra group showed higher mean values of leptin, adiponectin and malondialdehyde (MDA). In contrast, the glutathione (GSH) and superoxide dismutase (SOD) mean values were lower in the pyometra group as compared to the post-treatment and control groups. NPT levels in the post-treatment groups were lower than those in cows with pyometra but comparable to the healthy control group (p > .05). When compared to the other biomarkers, NPT, leptin and adiponectin showed higher sensitivity and specificity in identifying pyometra cases (AUC ≥0.99). The predominant bacterial isolates from the ptomtra-affected cows consisted of Escherichia coli (N = 29; 39.2%), Arcanobacterium pyogenes (N = 27; 36.5%) and Fusobacterium necrophorum (N = 13; 17.6%). Mixed infection was determined in nine samples (12.2%). Conclusively, OS, adiponectin, leptin and NPT play crucial roles in comprehending the development of postpartum pyometra in cows and have the potential to serve as biomarkers for the disease.

Elevated NET, Calprotectin, and Neopterin Levels Discriminate between Disease Activity in COVID-19, as Evidenced by Need for Hospitalization among Patients in Northern Italy

Coronavirus disease 2019 (COVID-19) displays clinical heterogeneity, but little information is available for patients with mild or very early disease. We aimed to characterize biomarkers that are useful for discriminating the hospitalization risk in a COVID-19 cohort from Northern Italy during the first pandemic wave. We enrolled and followed for four weeks 76 symptomatic SARS-CoV-2 positive patients and age/sex-matched healthy controls. Patients with mild disease were discharged (n.42), and the remaining patients were hospitalized (n.34). Blood was collected before any anti-inflammatory/immunosuppressive therapy and assessed for soluble C5b-9/C5a, H3-neutrophil extracellular traps (NETs), calprotectin, and DNase plasma levels via ELISA and a panel of proinflammatory cytokines via ELLA. Calprotectin and NET levels discriminate between hospitalized and non-hospitalized patients, while DNase negatively correlates with NET levels; there are positive correlations between calprotectin and both NET and neopterin levels. Neopterin levels increase in patients at the beginning of the disease and do so more in hospitalized than non-hospitalized patients. C5a and sC5b-9, and other acute phase proteins, correlate with neopterin, calprotectin, and DNase. Both NET and neopterin levels negatively correlate with platelet count. We show that calprotectin, NETs, and neopterin are important proinflammatory parameters potentially useful for discriminating between COVID-19 patients at risk of hospitalization.

Biological variation of serum neopterin concentrations in apparently healthy individuals

OBJECTIVES

The aims of this study were to determine the biological variation (BV), reference change value (RCV), index of individuality (II), and quality specifications for serum neopterin concentrations; a measurand provided by clinical laboratories as an indicator of cellular immunity.

METHODS

The study delivered serum samples collected for 10 consecutive weeks from 12 apparently healthy individuals (3 male, 9 female). Serum neopterin concentrations were measured using high-performance liquid chromatography with fluorometric detection. The data analysis was performed using an online statistical tool and addressed published criteria for estimation of biological variation.

RESULTS

The mean neopterin concentration was 5.26 nmol/L. The within-subject biological variation (CVI) with 95 % confidence interval (CI) of neopterin serum concentrations was 11.54 % (9.98-13.59), and the between-subject biological variation (CVG) with 95 % CI was 43.27 % (30.52-73.67). The neopterin asymmetrical RCV was -24.9 %/+33.1 %, and the II was 0.27. The desirable quality specifications for neopterin were <5.77 % for precision, <11.20 % for bias, and <20.72 % for total allowable error (TEa). When analytical variation was used instead of CVI to calculate TEa, the desirable TEa was <18.39.

CONCLUSIONS

This study determined BV data for neopterin, an indicator of cell-mediated immune response. Asymmetric RCV values, of 24.9 % decrease or a 33.1 % increase between consecutive measurements indicate significant change. The II of 0.27 indicates a high degree of individuality, therefore that it is appropriate to consider the use of personal reference data and significance of change rather than the reference interval as points of reference for the evaluation of neopterin serum concentrations.

Modulation of cell-mediated immunity during pregnancy in wild bonobos

During pregnancy, the mammalian immune system must simultaneously protect against pathogens while being accommodating to the foreign fetal tissues. Our current understanding of this immune modulation derives predominantly from industrialized human populations and laboratory animals. However, their environments differ considerably from the pathogen-rich, resource-scarce environments in which pregnancy and the immune system co-evolved. For a better understanding of immune modulation during pregnancy in challenging environments, we measured urinary neopterin, a biomarker of cell-mediated immune responses, in 10 wild female bonobos (Pan paniscus) before, during and after pregnancy. Bonobos, sharing evolutionary roots and pregnancy characteristics with humans, serve as an ideal model for such investigation. Despite distinct environments, we hypothesized that cell-mediated immune modulation during pregnancy is similar between bonobos and humans. As predicted, neopterin levels were higher during than outside of pregnancy, and highest in the third trimester, with a significant decline post-partum. Our findings suggest shared mechanisms of cell-mediated immune modulation during pregnancy in bonobos and humans that are robust despite distinct environmental conditions. We propose that these patterns indicate shared immunological processes during pregnancy among hominins, and possibly other primates. This finding enhances our understanding of reproductive immunology.

Enhanced expression of neopterin in valve tissue of bicuspid aortic stenosis

Background

Aortic valve stenosis (AS) occurs in bicuspid aortic valve (BAV) patients at a relatively young age compared to tricuspid aortic valve (TAV) patients. However, the underlying cause of this phenomenon remains unknown. Neopterin, which is a by-product of the guanosine triphosphate (GTP) pathway, enhances the oxidative potential of reactive oxygen species. To clarify the role of neopterin in the aortic valve, we immunohistochemically studied the presence of neopterin in aortic valve specimens from patients with AS harboring either TAV or BAV.

Methods

Frozen aortic valve samples were surgically obtained from 68 patients with severe AS with TAV (n=34) and BAV (n=34). Normal aortic valves were obtained from cadavers who died of non-cardiovascular causes as controls (n=9). Samples were immunohistochemically stained with antibodies against smooth muscle cells, macrophages, T lymphocytes, neopterin, and 4-hydroxy-2-nonenal (4-HNE).

Results

Quantitative analysis showed that the percentage of macrophages, 4-HNE- and neopterin-positive macrophage score, and the number of T lymphocytes were significantly higher in BAV patients than in TAV patients (macrophages, P=0.013; T lymphocytes, P=0.011; neopterin, P<0.001; 4-HNE, P=0.008). Double immunostaining for neopterin and macrophages demonstrated that most neopterin-positive cells were macrophages in BAV patients.

Conclusions

Neopterin accumulation in macrophages may increase oxidative stress and contribute to the early onset of AS in BAV.

Autoimmune inflammatory myopathy biomarkers

The autoimmune inflammatory myopathy disease spectrum, commonly known as myositis, is a group of systemic diseases that mainly affect the muscles, skin and lungs. Biomarker assessment helps in understanding disease mechanisms, allowing for the implementation of precise strategies in the classification, diagnosis, and management of these diseases. This review examines the pathogenic mechanisms and highlights current data on blood and tissue biomarkers of autoimmune inflammatory myopathies.

Altered kynurenine pathway metabolism and association with disease activity in patients with systemic lupus

Systemic lupus erythematosus (SLE) is an autoimmune disease accompanied by increased release of proinflammatory cytokines that are known to activate the indoleamine 2,3-dioxygenase (IDO-1) enzyme, which catalyzes the rate-limiting step of the kynurenine pathway (KP). This study aimed to measure KP metabolite levels in patients with SLE and investigate the relationship between disease activity, clinical findings, and KP. The study included 100 patients with SLE and 100 healthy controls. Serum tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxyanthranilic acid (3HAA), 3-hydroxykynurenine (3HK), quinolinic acid (QA) concentrations were measured with tandem mass spectrometry. Serum KYN, KYNA, 3HAA, 3HK, and QA levels of the patients with SLE were significantly higher than the control group. Serum QA levels were elevated in patients with neurological involvement (four patients with peripheral neuropathy and two patients with mononeuropathy), serum KYN levels and KYN/TRP ratio increased in patients with joint involvement, and serum KYN, 3HK, and 3HAA levels and the KYN/TRP ratio were increased in patients with renal involvement. Moreover, KYN and KYN/TRP ratios were positively correlated with the disease activity score. These findings indicated that imbalances in KP metabolites may be associated with the pathogenesis, activation, and clinical manifestations of SLE.

Characteristics and evaluation of atherosclerotic plaques: an overview of state-of-the-art techniques

Atherosclerosis is an important cause of cerebrovascular and cardiovascular disease (CVD). Lipid infiltration, inflammation, and altered vascular stress are the critical mechanisms that cause atherosclerotic plaque formation. The hallmarks of the progression of atherosclerosis include plaque ulceration, rupture, neovascularization, and intraplaque hemorrhage, all of which are closely associated with the occurrence of CVD. Assessing the severity of atherosclerosis and plaque vulnerability is crucial for the prevention and treatment of CVD. Integrating imaging techniques for evaluating the characteristics of atherosclerotic plaques with computer simulations yields insights into plaque inflammation levels, spatial morphology, and intravascular stress distribution, resulting in a more realistic and accurate estimation of plaque state. Here, we review the characteristics and advancing techniques used to analyze intracranial and extracranial atherosclerotic plaques to provide a comprehensive understanding of atheroma.

A systematic review and meta-analysis of neopterin in rheumatic diseases

Introduction

Novel biomarkers of inflammation and oxidative stress might enhance the early recognition, management, and clinical outcomes of patients with rheumatic diseases (RDs). We assessed the available evidence regarding the pathophysiological role of neopterin, the oxidation product of 7,8-dihydroneopterin, a pteridine generated in macrophages activated by interferon-γ, by conducting a systematic review and meta-analysis of studies reporting its concentrations in biological fluids in RD patients and healthy controls.

Methods

We searched electronic databases for relevant articles published between inception and 31 August 2023. The risk of bias and the certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and the Grades of Recommendation, Assessment, Development and Evaluation Working Group system, respectively.

Results

In 37 studies, when compared to healthy controls, RD patients had significantly higher concentrations of neopterin both in plasma or serum (standard mean difference, SMD=1.31, 95% CI 1.01 to 1.61; p<0.001; moderate certainty of evidence) and in the urine (SMD=1.65, 95% CI 0.86 to 2.43, p<0.001; I2 = 94.2%, p<0.001; low certainty of evidence). The results were stable in sensitivity analysis. There were non-significant associations in meta-regression and subgroup analysis between the effect size and age, male to female ratio, year of publication, sample size, RD duration, C-reactive protein, erythrocyte sedimentation rate, specific type of RD, presence of connective tissue disease, analytical method used, or biological matrix investigated (plasma vs. serum). By contrast, the effect size was significantly associated with the geographical area in studies assessing serum or plasma and with the type of RD in studies assessing urine.

Discussion

Pending additional studies that also focus on early forms of disease, our systematic review and meta-analysis supports the proposition that neopterin, a biomarker of inflammation and oxidative stress, can be useful for the identification of RDs. (PROSPERO registration number: CRD42023450209).

Systematic review registration

PROSPERO, identifier CRD42023450209.

Assessment of serum neopterin and calprotectin as biomarkers for subclinical inflammation in patients with familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is the most common autoinflammatory disease characterized by short, repeated, and self-limiting attacks of fever and serositis. Subclinical inflammation can persist in the periods with no symptoms and result in amyloidosis even with colchicine treatment. Neopterin and calprotectin have been considered essential players in inflammation and immune response.

AIM

The study was aimed to measure serum levels of neopterin and calprotectin in patients with FMF in the attack-free period.

METHODS

A total of 160 participants were recruited from the rheumatology department in this single-center, case-control study. Individuals having the inclusion criteria were divided into healthy controls (n = 80) and FMF (n = 80). The laboratory data were acquired from the electronic registration database. Serum calprotectin and neopterin were measured with ELISA test kits. FMF patients and healthy controls' laboratory findings were compared.

RESULTS

FMF patients' serum red cell distribution width (RDW), calprotectin, and neopterin values were significantly higher compared to healthy controls. There were no statistically significant differences between calprotectin and neopterin regarding gender, family history, and colchicine response of the FMF patients.

CONCLUSIONS

Calprotectin, neopterin, and RDW can be valuable marker candidates to be used in the follow-up of subclinical inflammation in FMF patients.

Neopterin, the Cell-Mediated Immune Response Biomarker, in Inflammatory Periodontal Diseases: A Narrative Review of a More than Fifty Years Old Biomarker

Neopterin is a biomarker of the activation of cellular immunity. The purpose of this review is to summarise neopterin metabolism, methods of its detection, and its role in inflammation, focusing on periodontal inflammatory diseases. This derivative of guanosine is a non-enzymatic product of 7,8-dihydroneopterin oxidation caused by free radicals which protect activated macrophages from oxidative stress. Various methods, usually based on enzyme-linked immunosorbent essay, high-performance liquid chromatography, or radioimmunoassay were developed for the isolation of neopterin. A wide spectrum of diseases and conditions are known to affect neopterin levels, including cardiovascular, bacterial, viral, and degenerative diseases, as well as malignant tumours. Neopterin levels were found to increase in subjects with periodontitis, especially when the oral fluid and gingival crevicular fluid were evaluated. These findings confirm the role of activated macrophages and cellular immunity in periodontal inflammatory diseases. The gingival crevicular fluid and the oral fluid appear to be the most valuable biologic fluids for the evaluation of neopterin levels in periodontitis. For gingival crevicular fluid, neopterin can be determined as the concentration or the so-called total amount. Nonsurgical periodontal treatment was associated with a decrease in neopterin levels, but an increase was also reported, suggesting the possible role of macrophages in the resolution of the periodontal lesion.

Exploratory Evaluation of Neopterin and Chitotriosidase as Potential Circulating Biomarkers for Colorectal Cancer

Chronic inflammation is demonstrated to play a direct role in carcinogenesis. Our exploratory study aimed to assess the potential added value of two inflammation biomarkers, chitotriosidase and neopterin, in follow-up evaluation of patients with colorectal cancer (CRC). An observational exploratory study was conducted. Patients with CRC and matched controls (1:1, age, sex, and living environment) were evaluated. The patients with CRC (CRC group) and controls were assessed at baseline (before surgical intervention for patients with CRC). Patients with CRC were also evaluated at 1-year follow-up. Significantly more patients with blood group A (54.5% vs. 25.0%) and smokers (50.0% vs. 22.7%) were in the CRC group. The serum values of chitotriosidase and neopterin were higher in CRC patients than in controls, but only neopterin reached the conventional level of statistical significance (p-value = 0.015). The circulating chitotriosidase and neopterin values decreased significantly at 1-year follow-up (p-value < 0.0001). Patients with higher N- and M-stage showed statistically significant higher levels of chitotriosidase and neopterin at baseline and 1-year follow-up (p-values < 0.03). Circulating chitotriosidase levels also showed statistically significant differences regarding baseline and 1-year follow-up on patients with CRC and different differentiation grades (p-values < 0.02). The circulating levels of neopterin significantly decreased at 1-year follow-up, indicating its potential as a prognostic marker. The circulating values of chitotriosidase and neopterin exhibit significant differences in patients with than without recurrences. Our results support further evaluation of chitotriosidase and neopterin as prognostic markers in patients with CRC.

Chitotriosidase and Neopterin as Potential Biomarkers for the Evaluation of Complicated Cholecystitis-A Pilot Study

Gallstones are a common surgical pathology. Laparoscopic cholecystectomy represents the elective treatment. Complicated cases can increase the rate of conversion, the duration, and the difficulty of the intervention, along with the hospitalization period. A prospective cohort study was conducted on 51 patients with gallstones. Only subjects with normal renal, pancreatic, and hepatic functions were included. The severity of cholecystitis was evaluated by considering the ultrasound examination, intraoperative findings, and pathology report. We evaluated two potential biomarkers, namely neopterin and chitotriosidase, by comparing their levels before and after the intervention for chronic (n = 36) and complicated (n = 15) cases, as well as their eventual association with the hospitalization period. Subjects with complicated cholecystitis had significantly higher (p = 0.01) neopterin levels at presentation (16.82 nmol/L vs. 11.92 nmol/L, median values), but the differences in chitotriosidase activity between complicated (170.00 nmol/mL/h) and chronic (160.00 nmol/mL/h) cases were not significant (p = 0.66). Patients with neopterin levels above the cut-off value 14.69 nmol/L had a 3.34 times higher risk of complicated cholecystitis. Twenty-four hours after the laparoscopic cholecystectomy, the differences in neopterin level and chitotriosidase activity between chronic and complicated cases were not significant. A significant decrease in chitotriosidase activity was observed after the intervention, only for complicated cases (190 nmol/mL/h vs. 145 nmol/mL/h, p = 0.007); for neopterin, the postoperative decrease was not statistically significant (19.42 nmol/L vs. 10.92 nmol/L, p = 0.06). No significant association with the hospitalization period was observed. Neopterin may be a useful biomarker for complicated cholecystitis, and chitotriosidase may have prognostic utility in early patient follow-up.

Determination of neopterin in urine of industrial workers by HPLC

This study aimed to determine neopterin levels in the urine of industrial workers by the high-performance liquid chromatography method. Intra- and inter-day precision values for neopterin in urine were less than 3.14, and accuracy (relative error) was better than 3.00%. The limits of detection and quantification of neopterin were 0.3 and 1.0 ng/mL, respectively. Also, the developed method was applied to real samples to determine the neopterin levels in the urines of industrial workers, who have been exposed to various chemicals such as formaldehyde, heavy metals and thinners. Urine neopterin levels of industrial workers including auto painters, bodywork and furniture workers were statistically compared with healthy volunteers. The highest and lowest values of urinary neopterin for industrial workers were obtained 908.96 and 119.86 μmol/mol, respectively. Our investigation demonstrates that there is a meaningful difference in urinary neopterin levels between the workers and the control groups (P<0.05). Workers in the auto paint, body and furniture business may have been exposed to a toxic environmental exposure in their occupation. As a result, an increase in the concentration of neopterin in the urine may be important in the diagnosis and treatment of various diseases.

Neopterin Levels in Periodontitis and after Nonsurgical Periodontal Therapy: Evaluation of Gingival Crevicular Fluid, Oral Fluid, Serum and Urinary Samples-A Case-Control Study

Periodontitis is a chronic inflammatory disease that leads to the destruction of the tooth-supporting tissues with complex immune response. Neopterin (Np), secreted via activated macrophages, is considered a biomarker of cellular immunity. The aim of this study was to evaluate the impact of periodontitis and nonsurgical periodontal therapy. Np gingival crevicular fluid (GCF), oral fluid, serum and urine levels were compared in subjects with periodontitis before periodontal treatment, three months after and in a healthy control. Np GCF concentrations in the study group after treatment were significantly higher than the control group (p = 0.038). The GCF total amount (amount of substance) was significantly higher in the study group before periodontal treatment than in the control group (p = 0.001) and higher than the levels taken after treatment collection (p = 0.024). The oral fluid Np concentrations in the study group after treatment were significantly increased compared to the before treatment concentrations (p = 0.020). The same trend was observed in the urine samples. Significant correlation was found between the serum and oral fluid Np concentrations (p = 0.001, ρ = 0.40). Our results confirm the impact of cellular immunity and macrophages on periodontitis and on the resolution of periodontal inflammation. The presence of neopterin in oral fluid most likely originates in the serum.

Insights into Molecular Structure of Pterins Suitable for Biomedical Applications

Pterins are an inseparable part of living organisms. Pterins participate in metabolic reactions mostly as tetrahydropterins. Dihydropterins are usually intermediates of these reactions, whereas oxidized pterins can be biomarkers of diseases. In this review, we analyze the available data on the quantum chemistry of unconjugated pterins as well as their photonics. This gives a comprehensive overview about the electronic structure of pterins and offers some benefits for biomedicine applications: (1) one can affect the enzymatic reactions of aromatic amino acid hydroxylases, NO synthases, and alkylglycerol monooxygenase through UV irradiation of H₄pterins since UV provokes electron donor reactions of H₄pterins; (2) the emission properties of H₂pterins and oxidized pterins can be used in fluorescence diagnostics; (3) two-photon absorption (TPA) should be used in such pterin-related infrared therapy because single-photon absorption in the UV range is inefficient and scatters in vivo; (4) one can affect pathogen organisms through TPA excitation of H₄pterin cofactors, such as the molybdenum cofactor, leading to its detachment from proteins and subsequent oxidation; (5) metal nanostructures can be used for the UV-vis, fluorescence, and Raman spectroscopy detection of pterin biomarkers. Therefore, we investigated both the biochemistry and physical chemistry of pterins and suggested some potential prospects for pterin-related biomedicine.

Salivary Diagnostic for Monitoring Strenuous Exercise-A Pilot Study in a Cohort of Male Ultramarathon Runners

Intense physical stress, such as that in ultramarathon running, affects the immune system. For monitoring in sports medicine, non-invasive methods, e.g., salivary analysis, are of interest. This pilot cohort study aimed to assess changes in salivary parameters in response to an ultramarathon. The results were compared to blood parameters. Male, healthy finishers (n = 9, mean age: 48 ± 8.8 years, mean height: 1.8 ± 0.1 m, mean weight: 72.5 ± 7.2 kg, mean BMI: 23.5 ± 1.9 kg/cm²) of a 160 km ultramarathon were included. Saliva and blood samples were collected at three time points: T1 (baseline), T2 (shortly after the ultramarathon) and T3 (after recovery). In saliva, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, albumin, IgA, α-amylase, aMMP-8, and neopterin were assessed via ELISA. In blood, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, blood cell counts, procalcitonin, CRP, osmolality, albumin, and α-amylase were analyzed. The statistical evaluation comprised longitudinal testing and cross-sectional testing between saliva and blood using ratios of T2 and T3 to baseline values. Various parameters in saliva and blood changed in response to the ultramarathon. Comparing blood and saliva, the longitudinal changes of testosterone (p = 0.02) and α-amylase (p = 0.03) differed significantly. Despite the limitations of the study, it underlines that saliva is an interesting option for comprehensive monitoring in sports medicine and necessitates further studies.

Inflammatory markers calprotectin, NETs, syndecan-1 and neopterin in COVID-19 convalescent blood donors

Persisting inflammation has been discovered in lungs and other parenchymatous organs of some COVID-19 convalescents. Calprotectin, neutrophil extracellular traps (NETs), syndecan-1 and neopterin are general key inflammatory markers, and systemically enhanced levels of them may remain after the COVID-19 infection. These inflammatory markers were therefore measured in serum samples of 129 COVID-19 convalescent and 27 healthy blood donors or employees at Oslo Blood bank, Norway. Also antibodies against SARS-CoV-2 nucleocapsid antigen were measured, and timing of sampling and severity of infection noted. Whereas neopterin and NETs values remained low and those for syndecan-1 were not raised to statistically significant level, concentrations for calprotectin, as measured by a novel mixed monoclonal assay, were significantly increased in the convalescents. Antibodies against SARS-CoV-2 nucleocapsid antigen were elevated, but did not correlate with levels of inflammatory markers. Difference between the groups in only one biomarker makes evaluation of ongoing or residual inflammation in the convalescents difficult. If there is a low-grade inflammation, it would in that case involve neutrophils.

CD36 down regulation by the macrophage antioxidant 7,8-dihydroneopterin through modulation of PPAR-γ activity

CD36 is the key scavenger receptor driving the formation of cholesterol loaded foam cells, the principal cellular component of atherosclerotic plaques. CD36 is down regulated by 7,8-dihydroneopterin, a potent superoxide and hypochlorite scavenging antioxidant generated by interferon-γ stimulated macrophages. 7,8-dihydroneopterin down regulates CD36 mRNA and protein levels so inhibiting macrophage foam cell formation in vitro.We examined the mechanism of 7,8-dihydroneopterin down regulation of CD36 by measuring CD36 and PPAR-γ levels by western blot analysis, in the monocyte-like U937 cells with a range of PPAR-γ stimulants and inhibitors. Lipoxygenase activity was measured by monitoring linoleic acid oxidation at 234 nm for diene formation.Between 100 and 200 μM, 7,8-dihydroneopterin decreased CD36 levels by 50% within 12 hours with levels dropping below 25% by 24 hours. CD36 levels returned to basal levels after 24 hours. Inhibition of protein synthesis by cycloheximide show 7,8-dihydroneopterin had no effect on CD36 degradation rates. PPAR-γ levels were not altered by the addition of 7,8-dihydroneopterin. MAP Kinase, P38 and NF-κB pathways inhibitors SP600125, PD98059, SB202190 and BAY 11-7082 respectively, did not restore the CD36 levels in the presence of 7,8-dihydroneopterin. The addition the lipophilic PPAR-γ activators rosiglitazone and azelaoyl-PAF prevented the CD36 down regulation by 7,8-dihydroneopterin. 7,8-dihydroneopterin inhibited soybean lipoxygenase and reduced U937 cell basal levels of cellular lipid oxides as measured by HPLC-TBARS analysis.The data shows 7,8-dihydroneopterin down regulates CD36 expression by decreasing the level of lipid oxide stimulation of PPAR-γ promotor activity, potentially through lipoxygenase inhibition.

Role of neopterin as an inflammatory biomarker in congestive heart failure with insights on effect of drug therapies on its level

Inflammation has a major role in the pathogenesis of heart failure (HF). It triggers a cascade that leads to the release of pro-inflammatory cytokines which in turn cause cardiac hypertrophy, fibrosis, apoptosis, negative inotorpy and leukocyte recruitment which worsen the condition. Neopterin is an inflammatory biomarker which is released as a response to macrophage activation. Levels of neopterin are elevated in conditions which has an immunological component such as autoimmune disease, viral and bacterial infections and malignancy. Neopterin levels were found to be elevated in patients with HF. This is due to the fact that inflammation takes place during the development of the condition. Studies demonstrated that neopterin can be used as a biomarker for diagnosing HF, determining severity of the disease and monitoring its progression. Neopterin levels were higher in patients with New York Heart Association classification (NYHA) III–IV more than class I–II. Moreover, neopterin levels correlated well with morbidity and mortality. It has been suggested that neopterin be monitored levels to determine effectiveness of HF treatment options.

Physical-Exercise-Induced Antioxidant Effects on the Brain and Skeletal Muscle

Erythroid-related nuclear factor 2 (NRF2) and the antioxidant-responsive-elements (ARE) signaling pathway are the master regulators of cell antioxidant defenses, playing a key role in maintaining cellular homeostasis, a scenario in which proper mitochondrial function is essential. Increasing evidence indicates that the regular practice of physical exercise increases cellular antioxidant defenses by activating NRF2 signaling. This manuscript reviewed classic and ongoing research on the beneficial effects of exercise on the antioxidant system in both the brain and skeletal muscle.

Kinetics of Biomarkers of Oxidative Stress in Septic Shock: A Pilot Study

Septic shock is a major cause of mortality in ICU patients, its pathophysiology is complex and not properly understood. Oxidative stress seems to be one of the most important mechanisms of shock progression to multiple organ failure. In the present pilot study, we have analysed eight oxidative-stress-related biomarkers in seven consecutive time points (i.e., the first seven days) in 21 septic shock patients admitted to the ICU. Our objective was to describe the kinetics of four biomarkers related to pro-oxidative processes (nitrite/nitrate, malondialdehyde, 8-oxo-2′-deoxyguanosine, soluble endoglin) compared to four biomarkers of antioxidant processes (the ferric reducing ability of plasma, superoxide dismutase, asymmetric dimethylarginine, mid-regional pro-adrenomedullin) and four inflammatory biomarkers (CRP, IL-6, IL-10 and neopterin). Furthermore, we analysed each biomarker’s ability to predict mortality at the time of admission and 12 h after admission. Although a small number of study subjects were recruited, we have identified four promising molecules for further investigation: soluble endoglin, superoxide dismutase, asymmetric dimethylarginine and neopterin.

Lactobacillus plantarum induces innate cytokine responses that potentially provide a protective benefit against COVID-19: A single-arm, double-blind, prospective trial combined with an in vitro cytokine response assay

Intestinal microbiota can indirectly modulate airway physiology and immunity through the gut-lung axis. Recent microbiome studies indicate that patients with coronavirus disease 2019 (COVID-19) exhibit a specific intestinal dysbiosis that is closely associated with the disease pathophysiology. Therefore, rebalancing the intestinal microbiome using probiotics may be effective for controlling COVID-19. However, the rationale for using probiotics in COVID-19 remains unclear. In the present study, an in vitro cytokine response assay was conducted, followed by a single-arm, double-blind, prospective trial to evaluate the immunological efficacy of probiotic lactic acid bacteria against COVID-19. The present study focused on Lactobacillus plantarum (L. plantarum), Bifidobacterium longum and Lactococcus lactis ssp. lactis, which exhibit robust protective effects against infection with respiratory RNA viruses. Considering the feasibility of long-term daily intake for prophylactic purposes, healthy uninfected individuals were enrolled as subjects. Our previous pilot trial demonstrated that oral Qingfei Paidu decoction (QFPD), a Chinese herbal medicine formulated specifically against COVID-19, upregulates plasma TNF-α, IL-1β, IL-18 and IL-8. Therefore, the present study utilized the cytokine changes induced by QFPD to define the innate cytokine index QICI [=(TNF-α) x (IL-1β) x (IL-18) x (IL-8)/(IL-6)] as an indicator of the anti-COVID-19 immunomodulatory potential of the lactic acid bacteria. A total of 20 eligible volunteers were enrolled, 18 of whom completed the intervention. L. plantarum demonstrated a strikingly high innate cytokine index in all subjects in the in vitro cytokine response assay. In the subsequent trial, oral intake of L. plantarum significantly increased the innate cytokine index (mean fold change, 17-fold; P=0.0138) and decreased the plasma level of IL-6 (P=0.0128), a key driver of complex immune dysregulation in COVID-19, as compared with the baseline. The cytokine index increased in 16 of 18 subjects (88.9%) with considerable individual differences in the fold change (1- to 128-fold). In line with these innate cytokine changes, L. plantarum ingestion significantly enhanced the activity of natural killer cells. By contrast, oral B. longum failed to induce a significant increase in the innate cytokine index (mean fold change, 2-fold; P=0.474) as compared with the baseline. In conclusion, L. plantarum demonstrated superior QFPD-like immunomodulatory ability and mimicked the blood cytokine environment produced by early immune responses to viral infection. Daily consumption of L. plantarum as an anti-COVID-19 probiotic may be a possible option for preventing COVID-19 during the pandemic. The present study was prospectively registered in the University Hospital Medical Information Network-Clinical Trials Registry under the trial number UMIN000040479 on 22 May 2020 (https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046202).

Salivary neopterin and related pterins: their comparison to those in plasma and changes in individuals

Neopterin (NP), biopterin (BP) and monapterin (MP) exist in saliva. The physiological role of salivary NP as well as the pathophysiological role of increased NP in the immune-activated state has been unclear. Saliva is a characteristic specimen different from other body fluids. In this study, we analysed salivary NP and related pterin compounds, BP and MP and revealed some of its feature. High-performance liquid chromatography (HPLC) analysis of saliva and plasma obtained from 26 volunteers revealed that salivary NP existed mostly in its fully oxidized form. The results suggested that salivary NP as well as BP would mostly originate from the oral cavity, perhaps the salivary glands, and that salivary NP levels might not reflect those in the plasma. We also found that a gender difference existed in correlations between concentrations of salivary total concentrations of NP (tNP) and BP (tBP). HPLC analysis of saliva obtained from 5 volunteers revealed that the concentrations of salivary tNP as well as tBP fluctuated in an irregular fashion in various individuals. MP, a diastereomer of NP, might have come from oral cavity NP itself or its precursor. These results indicated that the nature of salivary NP might be different from that of NP in the blood or urine.

Hypoxic and Hyperoxic Breathing as a Complement to Low-Intensity Physical Exercise Programs: A Proof-of-Principle Study

Inflammation is an adaptive response to both external and internal stimuli including infection, trauma, surgery, ischemia-reperfusion, or malignancy. A number of studies indicate that physical activity is an effective means of reducing acute systemic and low-level inflammation occurring in different pathological conditions and in the recovery phase after disease. As a proof-of-principle, we hypothesized that low-intensity workout performed under modified oxygen supply would elicit a "metabolic exercise" inducing a hormetic response, increasing the metabolic load and oxidative stress with the same overall effect expected after a higher intensity or charge exercise. Herein, we report the effect of a 5-week low-intensity, non-training, exercise program in a group of young healthy subjects in combination with the exposure to hyperoxia (30% and 100% pO₂, respectively) or light hypoxia (15% pO₂) during workout sessions on several inflammation and oxidative stress parameters, namely hemoglobin (Hb), redox state, nitric oxide metabolite (NOx), inducible nitric oxide synthase (iNOS), inflammatory cytokine expression (TNF-α, interleukin (IL)-6, IL-10), and renal functional biomarkers (creatinine, neopterin, and urates). We confirmed our previous reports demonstrating that intermittent hyperoxia induces the normobaric oxygen paradox (NOP), a response overlapping the exposure to hypoxia. Our data also suggest that the administration of modified air composition is an expedient complement to a light physical exercise program to achieve a significant modulation of inflammatory and immune parameters, including cytokines expression, iNOS activity, and oxidative stress parameters. This strategy can be of pivotal interest in all those conditions characterized by the inability to achieve a sufficient workload intensity, such as severe cardiovascular alterations and articular injuries failing to effectively gain a significant improvement of physical capacity.

Urinary neopterin and total neopterin measurements allow monitoring of oxidative stress and inflammation levels of knee and hip arthroplasty patients

Knee and hip arthroplasty are common surgeries within an aging population. Some data has suggested that knee arthroplasty is more traumatic to the body than hip arthroplasty due to the increased complexity and load bearing nature of the joint. Here, we compare the stress of the two surgeries by measuring urinary neopterin and total neopterin as biomarkers of oxidative stress and inflammation. Urinary neopterin and total neopterin (neopterin + 7,8-dihydroneopterin) levels were analysed in 28 knee and 22 hip arthroplasty patients pre- and post-operatively to determine oxidative stress and inflammation levels. Total neopterin was 31.1% higher with knee arthroplasty (p<0.05). Urinary neopterin was 32.8% higher in the knee arthroplasty group versus hips. The increase in neopterin and total neopterin following a post-surgical decrease in levels was significant in both groups. Levels of neopterin and total neopterin were varied between patients, but all increased following surgery and subsided by day 28. The increased levels of urinary neopterin and total neopterin from knee arthroplasty indicate that knee osteoarthritis and arthroplasty is a more significant trauma to the body than hip osteoarthritis and arthroplasty surgery. This is also shown by faster inflammatory resolution following hip arthroplasty.

Mechanistic Biomarkers in Toxicology

Biomarkers are important parameters that are reliable, applicable, reproducible, and generally inexpensive. All biomarkers have a significant role in human health, especially mechanistic biomarkers, which are the most important for the prevention of toxic effects and diseases. They demonstrate the possibility of diagnosis, prognosis, recurrence, and spread of disease. Furthermore, they show the exposure levels to numerous chemical, biological, and physical agents. To date, the development and application of biomarkers require the knowledge of mechanisms underlying their production. Therefore, the present study focused on the possible mechanistic biomarkers.

Changes of body composition and circulating neopterin, omentin-1, and chemerin in response to thylakoid-rich spinach extract with a hypocaloric diet in obese women with polycystic ovary syndrome: A randomized controlled trial

This trial evaluated the effects of thylakoid-rich spinach extract supplementation combined with a hypocaloric diet on body composition and serum levels of neopterin, chemerin, and omentin-1 in obese women with polycystic ovary syndrome (PCOS). In this randomized controlled trial, 48 obese women with PCOS, aged 20-45 years old, were recruited and randomly divided into thylakoid (n = 24) and placebo (n = 24) groups. They received a low-calorie diet with 5 g/day thylakoid-rich spinach extract or a low-calorie diet with 5 g/day placebo for 12 weeks. The mean age of the participants of the thylakoid group was 31.86 years, and the placebo group was 32.04 years. Thylakoid-rich spinach extract supplementation with a low-calorie diet increased serum levels of omentin-1 (10.90 vs. 3.87 ng/L; p < .001) and decreased fat mass (-5.19 vs. -1.35 kg; p < .001) and serum levels of neopterin (-0.66 vs. -0.38 nmol/L; p = .003) and chemerin (-41.24 vs. -11.26 ng/L; p < .001) in the thylakoid group compared to the placebo group. A significant improvement in omentin-1, chemerin, and neopterin by thylakoid-rich spinach extract supplementation was under the influence of weight change and insulin resistance status throughout the study. A significant decrease in the other anthropometric indices and insulin resistance was also observed in the thylakoid group, compared to the placebo group (p < .001, for all parameters). Thylakoid-rich spinach extract combined with a low-calorie diet increased circulating omentin-1 and decreased fat mass, abdominal obesity, as well as circulating chemerin, neopterin, and insulin in obese women with PCOS.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Effect of high intake of cod or salmon on serum total neopterin concentration: a randomised clinical trial

Purpose

Primarily, to investigate the effect of high intake of cod (lean fish) or salmon (fatty fish) on serum concentration of total neopterin, a marker of cellular immune activation that is associated with cardiovascular disease. Second, to investigate effects of high cod/salmon intake on antioxidant vitamins and elements essential for activity of antioxidant enzymes.

Methods

In this randomised clinical trial, 63 participants with overweight/obesity consumed 750 g/week of either Atlantic cod (N = 22) or Atlantic salmon (N = 22) or were instructed to continue their normal eating habits but avoid fish intake (Control group, N = 19) for 8 weeks. Food intake was recorded, and fasting serum were collected at baseline and endpoint.

Results

Serum total neopterin concentration was reduced in the Cod group (median change − 2.65 (25th, 75th percentiles − 3.68, − 0.45) nmol/l, P = 0.018) but not in the Salmon group (median change 0.00 (25th, 75th percentiles − 4.15, 3.05) nmol/l, P = 0.59) when compared with the Control group after 8 weeks. The estimated daily intake of selenium, iron, magnesium and zinc were similar between all groups. Increased serum concentration of selenium was observed only after cod intake when compared to the Control group (P = 0.017). Changes in serum concentrations of copper, iron, magnesium, all-trans retinol, α-tocopherol and γ-tocopherol were similar between the groups.

Conclusion

A high intake of cod, but not of salmon, lowered serum total neopterin concentration when compared to the Control group.

Clinical trial registration

This trial was registered at clinicaltrials.gov as NCT02350595

Distinct lipid profile, low-level inflammation, and increased antioxidant defense signature in HIV-1 elite control status

HIV-1 elite controllers (EC) are a rare but heterogeneous group of HIV-1-infected individuals who can suppress viral replication in the absence of antiretroviral therapy. The mechanisms of how EC achieve undetectable viral loads remain unclear. This study aimed to investigate host plasma metabolomics and targeted plasma proteomics in a Swedish HIV-1 cohort including EC and treatment-naïve viremic progressors (VP) as well as HIV-negative individuals (HC) to get insights into EC phenotype. Metabolites belonging to antioxidant defense had higher levels in EC relative to VP, whereas inflammation markers were increased in VP compared with EC. Only four plasma proteins (CCL4, CCL7, CCL20, and NOS3) were increased in EC compared with HC, and CCL20/CCR6 axis can play an essential role in EC status. Our study suggests that low-level inflammation and oxidative stress at physiological levels could be important factors contributing to elite control phenotype.

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Increased acylcholine as unique HIV-1 positive elite controllers (EC) feature

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Physiological oxidative stress and inflammation profile in EC

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Increased in CCL4, CCL7, CCL20, and NOS3 in EC compared with HIV-ve control

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CCR6-CCL20-dependent anti-HIV mechanism can play an essential role in EC status

MALDI TOF Mass Spectrometry Imaging of Blood Smear: Method Development and Evaluation

The aim of this study was to develop and evaluate matrix assisted LASER desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry imaging (MSI) of blood smear. Integrated light microscope and MALDI IT-TOF mass spectrometer, together with a matrix sublimation device, were used for analysis of blood smears coming from healthy male donors. Different blood plasma removal, matrix deposition, and instrumental settings were evaluated using the negative and positive ionization modes while agreement between the light microscopy images and the lateral distributions of cellular marker compounds served as the MSI quality indicator. Red and white blood cells chemical composition was analyzed using the differential m/z expression. Five seconds of exposure to ethanol followed by the 5 min of 9-aminoacridine or α-cyano-4-hydroxycinnamic acid deposition, together with two sets of instrumental settings, were selected for the MALDI TOF MSI experiments. Application of the thin and transparent matrix layers assured good correspondence between the LASER footprints and the preselected regions of interest. Cellular marker m/z signals coincided well with the appropriate cells. A metabolite databases search using the differentially expressed m/z produced hits which were consistent with the respective cell types. This study sets the foundations for application of blood smear MALDI TOF MSI in clinical diagnostics and research.

Relationship Between Serum Neopterin Level and Peripheral Arterial Plaque in Patients with Type 2 Diabetes

OBJECTIVE

Neopterin is an inflammatory factor synthesized by monocyte macrophages in response to γ-interferon. It plays an important role in regulating a variety of physiological and pathological processes, including obesity, diabetes, and cardiovascular disease. This study aims to clarify the relationship between peripheral arterial plaque and serum neopterin in type 2 diabetes.

METHODS

We consecutively selected 121 inpatients with type 2 diabetes. After collecting relevant clinical indicators, we collected serum from all patients and measured neopterin levels through enzyme linked immune sorbent assay. Peripheral arterial plaques (the carotid and femoral arteries) were detected by B-mode ultrasound. Multivariate logistic regression was used to determine the independent influencing factors. The correlation between neopterin levels and other variables was analyzed by Spearman correlation analysis. P <0.05 was considered to be statistically significant.

RESULTS

There was no difference in serum neopterin levels between arterial plaques group and no plaques group. Serum neopterin levels in patients with carotid plaque were elevated compared to patients without carotid plaque. Logistic regression analysis showed that a higher serum neopterin level was an independent risk factor for the presence of carotid plaques. Serum neopterin levels were positively correlated with BMI, HOMA-IR, and serum creatinine and negatively correlated with eGFR.

CONCLUSION

Serum neopterin levels were positively and independently associated with carotid plaque in patients with type 2 diabetes.

The Potential Benefit of Monitoring Oxidative Stress and Inflammation in the Prevention of Non-Communicable Diseases (NCDs)

The significant increase in worldwide morbidity and mortality from non-communicable diseases (NCDs) indicates that the efficacy of existing strategies addressing this crisis may need improvement. Early identification of the metabolic irregularities associated with the disease process may be a key to developing early intervention strategies. Unhealthy lifestyle behaviours are well established drivers of the development of several NCDs, but the impact of such behaviours on health can vary considerably between individuals. How can it be determined if an individual's unique set of lifestyle behaviours is producing disease? Accumulating evidence suggests that lifestyle-associated activation of oxidative and inflammatory processes is primary driver of the cell and tissue damage which underpins the development of NCDs. However, the benefit of monitoring subclinical inflammation and oxidative activity has not yet been established. After reviewing relevant studies in this context, we suggest that quantification of oxidative stress and inflammatory biomarkers during the disease-free prodromal stage of NCD development may have clinical relevance as a timely indicator of the presence of subclinical metabolic changes, in the individual, portending the development of disease. Monitoring markers of oxidative and inflammatory activity may therefore enable earlier and more efficient strategies to both prevent NCD development and/or monitor the effectiveness of treatment.

Antioxidant Supplementation Modulates Neutrophil Inflammatory Response to Exercise-Induced Stress

The aim of the present report was to evaluate the inflammatory response to a 2000-m running test considering neutrophil myeloperoxidase as an inflammatory marker, and to verify if supplements rich in antioxidants could modulate Post-test antioxidant and anti-inflammatory responses. To this end, a 21-day homogenization period was carried out with three groups: a control group, a supplemented group taking an almond beverage enriched with vitamins C and E and a third group consuming the same beverage but enriched with Lippia citriodora extract. At the end of this period, participants performed a 2000-m run, and blood samples were obtained the day before and immediately after the running test. Plasma and neutrophils were isolated. As a result, plasma creatine kinase and myoglobin increased, indicating Post-test muscle damage. Plasma oxidative markers were increased in all groups, except in the group supplemented with the almond beverage. Neutrophil antioxidant enzymes were significantly increased only in the control group, suggesting an antioxidant effect of the supplements provided in the other groups. Myeloperoxidase activity was significantly increased after the test in the control group, while increased enzyme levels were detected in plasma of the supplement groups. Therefore, antioxidant consumption seems to favour myeloperoxidase release. The connection of this observation with post-exercise recovery will require further investigation.

Neopterin serum level does not reflect the disease activity in rheumatoid arthritis: A systematic review and meta-analysis

Rheumatoid arthritis (RA) is a chronic autoimmune disease caused by established chronic inflammation. Neopterin levels have extensively been considered as a marker of immune activation during inflammation. In this study, we performed a systematic evaluation and meta-analysis to elucidate the overall relationship between neopterin concentration and RA disease activity. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review was conducted using PubMed, Google Scholar, Web of Science, and Scopus from 2000 to August 2020. The Newcastle-Ottawa scale was used to assess the quality of eligible studies. The effect size (ES) and corresponding 95% confidence intervals (CIs) were calculated to evaluate this association. A total of 15 studies out of 98 met our inclusion criteria. The pooled analysis found that patients with RA had high level of neopterin; however, no statistically significant association was found between neopterin levels with high, intermediate, and low diseases activity score (DAS)-28 (ES =11.18, 95% CI: 6.02 to 16.34, and I² = 91.8%; and ES = 8.57, 95% CI: 6.41 to 10.37, and I² = 99.5%; and ES =12.45, 95% CI: -1.68 to 26.58, and I² = 99.0%, respectively). Our results indicated that the neopterin concentration does not seem to have any substantial impact on the RA disease activity.

Theoretical determination of two-photon absorption in biologically relevant pterin derivatives

Given the prevalence of fluorescence spectroscopy in biological systems, and the prevalence of pterin derivatives throughout biological systems, presented here is an assessment of the two-photon absorption spectroscopy as it applies to a range of the most commonly studied pterin derivatives. QR-CAMB3LYP//ccpVTZ calculations suggest that the use of two-photon spectroscopic methods would enable a more capable differentiation between closely related derivatives in comparison to the one-photon spectra, which show minimal qualitative deviation. Study of short tail derivatives shows that, in most cases, two-photon accessible states solely involve the π* LUMO as the particle orbital, with biopterin, neopterin, and 6-(hydroxymethyl)pterin presenting exceptional potential for targetting. Investigation of derivatives in which the tail contains an aromatic ring resulted in the observation of a series of two-photon accessible states involving charge transfer from the tail to the pterin moiety, the cross sections of which are highly dependent on the adoption of a planar geometry. The observation of these states presents a novel method for tracking the substitution of biologically important molecules such as folic acid and 5-methenyltetrahydrofolylpolyglutamate.

Neopterin and biopterin levels and tryptophan degradation in patients with diabetes

This study aimed to evaluate the possible changes of neopterin, biopterin levels and tryptophan degradation in diabetes and to compare the results within diabetes groups and with healthy subjects. Diabetes mellitus patients and healthy controls were recruited the study. Patients were further subgrouped according to their drug therapy. Serum neopterin concentrations were detected by ELISA. Urinary neopterin, biopterin, serum tryptophan (Trp) and kynurenine (Kyn) levels were detected by HPLC. There was no difference between controls and diabetes patients in serum neopterin, urinary neopterin and biopterin levels (p > 0.05, all). Serum Trp and Kyn levels were significantly different in type 1 diabetes (T1DM) patients compared to controls (p < 0.05, both). Serum neopterin levels were significantly higher in type 2 diabetes patients (T2DM) compared to T1DM (p < 0.05). Urinary biopterin levels of T2DM patients using both metformin and vildagliptin were significantly higher than T1DM patients (p < 0.05). The correlations between serum neopterin and urinary neopterin, Kyn and Kyn/Trp were statistically significant in control and patient groups (p < 0.05, all). The study showed that Kyn/Trp was altered in diabetes patients due to immune modulation. On the other hand, although xenobiotic exposure may change pteridine levels, metformin and/or vildagliptin use in T2DM patients did not have any effect on the measured parameters.

Neopterin derivatives - a novel therapeutic target rather than biomarker for atherosclerosis and related diseases

This review provides an updated overview of the emerging roles of neopterin derivatives in atherosclerosis. Neopterin, a metabolite of guanosine triphosphate, is produced by interferon-γ-activated macrophages and is expressed at high levels in atheromatous plaques within the human carotid and coronary arteries as well as in the aorta. Plasma concentrations of neopterin are higher in patients with carotid, cerebral, and coronary artery diseases as well as aortic aneurysm. The concentration of neopterin is positively correlated with the severity of coronary artery disease. However, a prospective cohort study showed that neopterin contributes to protection against plaque formation in carotid arteries in patients with atherosclerosis. Moreover, using both in vitro and in vivo experiments, a recent study has shown the atheroprotective effects of neopterin. Neopterin suppresses the expression of monocyte chemotactic protein-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in endothelial cells, and thereby suppresses the adhesion of monocytes to endothelial cells. It also suppresses the inflammatory phenotype of monocyte-derived macrophages. In addition, neopterin suppresses oxidized low-density lipoprotein-induced foam cell formation in macrophages and the migration and proliferation of vascular smooth muscle cells. Neopterin injection into apolipoprotein E-deficient (Apoe^-/-) mice suppresses the development of atherosclerotic lesions. A neopterin derivative tetrahydroneopterin (BH4), also known as a cofactor for nitric oxide (NO) synthases, suppresses atherosclerosis and vascular injury-induced neointimal hyperplasia in Apoe^-/- mice. BH4 administration improves endothelial dysfunction in patients with coronary artery disease. These findings suggest that neopterin production may increase to counteract the progression of atherosclerosis, as neopterin contributes to atheroprotection. Otherwise, the increased neopterin levels in atherosclerosis may reflect a compensatory mechanism associated with inducible NO synthase upregulation in macrophages to supply BH4 for high output NO production caused by decreased endothelial NO synthase in atherosclerosis. Therefore, neopterin derivatives are a novel therapeutic target for atherosclerosis and related diseases.

Untargeted Metabolomic Profiling Using UHPLC-QTOF/MS Reveals Metabolic Alterations Associated with Autism

Autism spectrum disorder (ASD) is a clinical spectrum of neurodevelopment disorder characterized by deficits in social communication and social interaction along with repetitive/stereotyped behaviors. The current diagnosis for autism relies entirely on clinical evaluation and has many limitations. In this study, we aim to elucidate the potential mechanism behind autism and establish a series of potential biomarkers for diagnosis. Here, we established an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry- (UHPLC-QTOF/MS-) based metabonomic approach to discriminate the metabolic modifications between the cohort of autism patients and the healthy subjects. UHPLC-QTOF/MS analysis revealed that 24 of the identified potential biomarkers were primarily involved in amino acid or lipid metabolism and the tryptophan kynurenine pathway. The combination of nicotinamide, anthranilic acid, D-neopterin, and 7,8-dihydroneopterin allows for discrimination between ASD patients and controls, which were validated in an independent autism case-control cohort. The results indicated that UHPLC-QTOF/MS-based metabolomics is capable of rapidly profiling autism metabolites and is a promising technique for the discovery of potential biomarkers related to autism.

Associations Between Plasma Immunomodulatory and Inflammatory Mediators With VACS Index Scores Among Older HIV-Infected Adults on Antiretroviral Therapy

The prevalence of age-related comorbidities is increased in people living with HIV, even in those well-controlled on combination antiretroviral therapy (ART). Persistent immune activation and inflammation may play pivotal roles in the pathogenesis; however, the burden of morbidities in the older HIV infected population may be exacerbated and driven by distinct mechanisms. In a cross sectional study of 45 HIV-infected participants 60 years or older, we examined the relationships between 14 immunomodulatory and inflammatory factors and the Veterans Aging Cohort Study (VACS) Index, a metric of multimorbidity and mortality comprised of age, CD4 count, hemoglobin, Fibrosis-4 [FIB-4], and estimated glomerular filtration rate [eGFR], by linear regression analysis. All participants were virally suppressed (<50 HIV RNA copies/mL), on ART, and primarily Caucasian (86.7%), and male (91.1%). Plasma levels of monocyte/macrophage-associated (neopterin, IP-10, sCD163, sCD14, and MCP-1) and glycan-binding immunomodulatory factors (galectin (Gal)-1, Gal-3, and Gal-9) were assessed, as well as inflammatory biomarkers previously linked to the VACS Index (i.e., CRP, cystatin C, TNF-α, TNFRI, IL-6, and D-dimer) for comparison. In regression analysis, higher VACS index scores were associated with higher levels of neopterin, cystatin C, TNFRI, and Gal-9 (all p < 0.05), potentially driven by correlations found with individual VACS components, including age, CD4 count, FIB-4, and eGFR. Gal-9, cystatin C, and TNFRI directly correlated with the extent of multimorbidity. Multiple correlations among markers were observed, suggesting an interplay of overlapping, but distinct, pathways. Collectively, in addition to cystatin C and TNFRI, both galectin-9 and neopterin, independently emerged as novel fluid markers of the VACS Index and burden of comorbidity and may further guide in understanding pathogenic mechanisms of age-related disorders in older HIV-infected individuals on suppressive ART.

Oxidative stress and immune cell activation quantification in sepsis and non-sepsis critical care patients by neopterin/7,8-dihydroneopterin analysis

Introduction: Neopterin and 7,8-dihydroneopterin are used as biomarkers of oxidative stress and inflammation, but the effect of kidney function on these measurements has not been extensively explored. We examine the levels of oxidative stress, inflammation and kidney function in intensive patients and compare them to equivalent patients without sepsis.

Methods: 34 Intensive care patients were selected for the study, 14 without sepsis and 20 with. Both groups had equivalent levels of trauma, assessed by SAPS II, SOFA, and APACHE II and III scores. Plasma and urinary neopterin and total neopterin (neopterin + 7,8-dihydroneopterin) values were measured.

Results: Neopterin and total neopterin were significantly elevated in urine and plasma for multiple days in sepsis versus non-sepsis patients. Plasma neopterin and total neopterin have decreasing relationships with increased eGFR (p<0.008 and p<0.001, respectively). Plasma/urinary neopterin and total neopterin ratios demonstrate that total neopterin flux is more influenced by eGFR than neopterin, with significantce of p<0.02 and p<0.0002 respectively.

Conclusion: Sepsis patients present with greater levels of oxidative stress and immune system activation than non-sepsis patients of equal levels of trauma, as measured by neopterin and total neopterin. eGFR may need to be taken into account when accessing the level of inflammation from urinary neopterin measurements.

Neopterin formation through radical scavenging of superoxide by the macrophage synthesised antioxidant 7,8-dihydroneopterin

Clinical measurement of neopterin has been extensively used as a marker of inflammation but the in vivo mechanism generating neopterin is poorly understood. Neopterin is described as the oxidation product of 7,8-dihydroneopterin, a potent antioxidant generated by monocyte/macrophages in response to interferon-γ. While peroxyl and hydroxyl scavenging generates dihydroxanthopterin, hypochlorite efficiently oxidises 7,8-dihydroneopterin into neopterin, but this reaction alone does not explain the high levels of neopterin seen in clinical data. Here, we examine whether superoxide scavenging by 7,8-dihydroneopterin generates neopterin. U937 cells incubated with oxLDL showed a time dependent increase superoxide and 7,8-dihydroneopterin oxidation to neopterin. Neopterin generation in oxLDL or phorbol ester treated U937 cells or human monocytes was inhibited by apocynin and PEG-SOD. Addition of the myeloperoxidase inhibitor 4-aminobenzoic acid hydrazide (ABAH) had no effect of the superoxide generation or neopterin formation. 7,8-Dihydroneopterin reacted with superoxide/hydroxy radical mixtures generated by X-ray radiolysis to give neopterin. Formation of neopterin by superoxide derived from the xanthine/xanthine oxidase system was inhibited by superoxide dismutase. Neopterin formation was inhibited by apocynin in phorbol ester treated human carotid plaque rings in tissue culture. These results indicate that 7,8-dihydroneopterin scavenges superoxide and is subsequently oxidised into neopterin in cellular and cell-free experimental systems.

Cerebrospinal Fluid Neurofilament Light Chain Is Associated with Kynurenine Pathway Metabolite Changes in Multiple Sclerosis

Neurofilament light (NFL) has proved to be a good prognostic factor in multiple sclerosis (MS), as its level is proportionally elevated with extended neuraxonal damage. The involvement of the kynurenine pathway in neuroinflammation has been proved. The precursor of this pathway is the essential amino acid tryptophan, which is catabolized 95% towards kynurenine metabolites. Quinolinic acid (QUIN) within the brain is only produced in activated microglia and macrophages, leading to axonal degeneration via the activation of N-Methyl-D-aspartate receptors. Neopterin is a biomarker for inflammation produced by macrophages. The association of these biomarkers has not previously been investigated. Our aim was to assess whether there is an association of the neurodegenerative biomarker NFL with the markers of neuroinflammation, e.g., kynurenine metabolites and neopterin, in the cerebrospinal fluid (CSF). CSF samples of patients with MS (pwMS; n = 37) and age-matched controls (n = 22) were compared for NFL levels by ELISA, while the kynurenine pathway metabolites tryptophan and neopterin were detected with mass spectrometry. Spearman’s correlation showed that NFL is an independent predictor of neurological disability in the MS group. Significant correlations were found between NFL, neopterin, and QUIN, and between kynurenine and neopterin. Receiver operating characteristic (ROC) curve analysis was used to plot the top three best predictors of MS-related disability that yielded the best specificity and sensitivity. Normalized NFL (AUC: 0.923), QUIN (AUC: 0.803), and neopterin (AUC: 0.843) were the best independent predictors of neurological disability in pwMS. The CSF NFL and CSF QUIN, together with neopterin, were elevated in the CSF of pwMS compared to controls. The combination of the neurodegenerative biomarkers together with biomarkers of neuroinflammation could provide additional information on the underlying pathomechanism of disease activity, which is essential for the identification of patients at risk of developing cumulative disabilities.

Metabolic analysis of amino acids and vitamin B6 pathways in lymphoma survivors with cancer related chronic fatigue

Chronic cancer-related fatigue (CF) is a common and distressing condition in a subset of cancer survivors and common also after successful treatment of malignant lymphoma. The etiology and pathogenesis of CF is unknown, and lack of biomarkers hampers development of diagnostic tests and successful therapy. Recent studies on the changes of amino acid levels and other metabolites in patients with chronic fatigue syndrome/myalgic encephalopathy (CFS/ME) have pointed to possible central defects in energy metabolism. Here we report a comprehensive analysis of serum concentrations of amino acids, including metabolites of tryptophan, the kynurenine pathway and vitamin B6 in a well characterized national Norwegian cohort of lymphoma survivors after high-dose therapy and autologous stem cell transplantation. Among the 20 standard amino acids in humans, only tryptophan levels were significantly lower in both males and females with CF compared to non-fatigued survivors, a strikingly different pattern than seen in CFS/ME. Markers of tryptophan degradation by the kynurenine pathway (kynurenine/tryptophan ratio) and activation of vitamin B6 catabolism (pyridoxic acid/(pyridoxal + pyridoxal 5'-phosphate), PAr index) differed in survivors with or without CF and correlated with known markers of immune activation and inflammation, such as neopterin, C-reactive protein and Interleukin-6. Among personal traits and clinical findings assessed simultaneously in participating survivors, higher neuroticism score, obesity and higher PAr index were significantly associated with increased risk of CF. Collectively, these data point to low grade immune activation and inflammation as a basis for CF in lymphoma survivors.

Serum Neopterin Levels and the Clinical Presentation of COVID-19

In Coronavirus disease 2019 (COVID-19), it is important to evaluate disease activity and investigate possible biomarkers. Therefore, in this study, we investigated the relationship between disease activity and serum levels of possible immune activation marker neopterin in patients with COVID-19. The study enrolled 45 patients (23 females, 51.1%) treated for COVID-19. The patients were divided into two groups according to their clinical presentation: those who recovered quickly (Group 1) and those who worsened progressively (Group 2). The neopterin and C-reactive protein levels were high in all patients on admission. In Group 1, neopterin concentrations and serum neopterin/creatinine ratios were significantly higher on admission compared to Day 14 of the disease, whereas in Group 2, levels were significantly higher at Day 14 of the disease than on admission. Neopterin levels at admission were significantly higher in Group 1. The serum neopterin concentrations at admission were markedly higher in patients with a derived neutrophil–lymphocyte ratio (dNLR) > 2.8 compared to those with a dNLR ≤ 2.8 (p < 0.05). Serum neopterin levels can be used as a prognostic biomarker in predicting disease activity in COVID-19.