Serum total antioxidant capacity reflects severity of illness in patients with severe sepsis

The use of serum paraoxonase-1 to assess inflammation in horses with colitis serum paraoxonase-1 in horses with colitis

BACKGROUND

Paraoxonase-1 (PON-1) has been suggested as a marker of inflammation and oxidative stress in horses and could potentially be used for prognostication in horses with colitis.

OBJECTIVES

Assessment of PON-1 in horses with colitis and comparison of two methods.

METHODS

Serum PON-1 was measured by two methods (paraoxon and p-nitrophenyl acetate) in 161 horses with colitis and 57 controls. Follow-up samples obtained during hospitalization were available from 106 horses with colitis. The two methods were compared.

RESULTS

Serum PON-1 was significantly lower in horses with colitis than in healthy horses (P < .0001 for both methods) as well as in nonsurvivors compared with survivors (P = .0141 [paraoxon-based method] and P < .0001 [p-nitrophenyl acetate-based method]), but with marked overlap between groups. PON-1 activity did not change parallel to a change in inflammatory status in response to treatment when assessed at admission and in up to seven follow-up samples. Admission PON-1 activity could not reliably classify horses as survivors or nonsurvivors, with sensitivity and specificity ranging between 53.1% and 72.9%. Results from the two methods were comparable.

CONCLUSIONS

Both methods reliably measured serum PON-1 activity. Significant differences in PON-1 activity were found between healthy horses and horses with colitis and between survivors and nonsurvivors. However, PON-1 activity varied considerably within groups. Both the proposed reference intervals as well as alternative cutoff values resulted in suboptimal diagnostic and prognostic performance, and the use of serum PON-1 in horses with colitis thus seems to add little to existing diagnostic and prognostic markers.

Shared genetic correlations between kidney diseases and sepsis

Background

Clinical studies have indicated a comorbidity between sepsis and kidney diseases. Individuals with specific mutations that predispose them to kidney conditions are also at an elevated risk for developing sepsis, and vice versa. This suggests a potential shared genetic etiology that has not been fully elucidated.

Methods

Summary statistics data on exposure and outcomes were obtained from genome-wide association meta-analysis studies. We utilized these data to assess genetic correlations, employing a pleiotropy analysis method under the composite null hypothesis to identify pleiotropic loci. After mapping the loci to their corresponding genes, we conducted pathway analysis using Generalized Gene-Set Analysis of GWAS Data (MAGMA). Additionally, we utilized MAGMA gene-test and eQTL information (whole blood tissue) for further determination of gene involvement. Further investigation involved stratified LD score regression, using diverse immune cell data, to study the enrichment of SNP heritability in kidney-related diseases and sepsis. Furthermore, we employed Mendelian Randomization (MR) analysis to investigate the causality between kidney diseases and sepsis.

Results

In our genetic correlation analysis, we identified significant correlations among BUN, creatinine, UACR, serum urate, kidney stones, and sepsis. The PLACO analysis method identified 24 pleiotropic loci, pinpointing a total of 28 nearby genes. MAGMA gene-set enrichment analysis revealed a total of 50 pathways, and tissue-specific analysis indicated significant enrichment of five pairs of pleiotropic results in kidney tissue. MAGMA gene test and eQTL information (whole blood tissue) identified 33 and 76 pleiotropic genes, respectively. Notably, genes PPP2R3A for BUN, VAMP8 for UACR, DOCK7 for creatinine, and HIBADH for kidney stones were identified as shared risk genes by all three methods. In a series of immune cell-type-specific enrichment analyses of pleiotropy, we identified a total of 37 immune cells. However, MR analysis did not reveal any causal relationships among them.

Conclusions

This study lays the groundwork for shared etiological factors between kidney and sepsis. The confirmed pleiotropic loci, shared pathogenic genes, and enriched pathways and immune cells have enhanced our understanding of the multifaceted relationships among these diseases. This provides insights for early disease intervention and effective treatment, paving the way for further research in this field.

Improving geriatric outcomes through nutritional and immunonutritional strategies: Focus on surgical setting by a comprehensive evidence review

The aging population worldwide has led to an increased request for surgical interventions in older, geriatric, and frail patients. However, all the physiological changes related to aging are associated with many challenges in the perioperative period, strongly impacting surgical outcomes. Nutritional status plays a pivotal role in determining the resilience of older adults to surgical stress and their ability to recover postoperatively. It is well known that malnutrition, a prevalent concern in geriatrics, is linked to increased adverse outcomes, including morbidity and mortality. Recognizing the significance of preoperative nutritional screening, assessment, diagnosis, intervention, and monitoring is essential for optimizing surgical outcomes. In this context, immunonutrition, which involves the supplementation of specific nutrients to modulate immune responses, emerges as a promising strategy to mitigate the increased inflammatory response observed in geriatric surgical patients. This study reviews current literature on the impact of nutrition and immunonutrition on surgical outcomes in geriatrics, highlighting the potential benefits in terms of reduced complications, enhanced wound healing, and shortened hospital stays. Recognizing and addressing the specific nutritional needs of older persons undergoing surgery is essential for promoting successful surgical outcomes and improving overall quality of life in this vulnerable population.

Exploring the role of antioxidants in sepsis-associated oxidative stress: a comprehensive review

Sepsis is a potentially fatal condition characterized by organ dysfunction caused by an imbalanced immune response to infection. Although an increased inflammatory response significantly contributes to the pathogenesis of sepsis, several molecular mechanisms underlying the progression of sepsis are associated with increased cellular reactive oxygen species (ROS) generation and exhausted antioxidant pathways. This review article provides a comprehensive overview of the involvement of ROS in the pathophysiology of sepsis and the potential application of antioxidants with antimicrobial properties as an adjunct to primary therapies (fluid and antibiotic therapies) against sepsis. This article delves into the advantages and disadvantages associated with the utilization of antioxidants in the therapeutic approach to sepsis, which has been explored in a variety of animal models and clinical trials. While the application of antioxidants has been suggested as a potential therapy to suppress the immune response in cases where an intensified inflammatory reaction occurs, the use of multiple antioxidant agents can be beneficial as they can act additively or synergistically on different pathways, thereby enhancing the antioxidant defense. Furthermore, the utilization of immunoadjuvant therapy, specifically in septic patients displaying immunosuppressive tendencies, represents a promising advancement in sepsis therapy.

Effect of Metformin on Oxidative Stress and Left Ventricular Geometry in Nondiabetic Heart Failure Patients: A Randomized Controlled Trial

Introduction: There is an increasing interest in using metformin in cardiovascular diseases and its potential new roles. Only two randomized controlled trials investigated the effect of metformin in nondiabetic heart failure (HF) patients. However, none of these studies assess the role of metformin in reducing oxidative stress. We hypothesized that metformin might improve oxidative stress and left ventricular remodeling in nondiabetic HF patients with reduced ejection fraction (HFrEF). Methods and Methods: Seventy HFrEF patients (EF 37% ± 8%; median age 66 years) were randomized to metformin (n = 35) or standard of care (SOC) for HF (n = 35) for 6 months in addition to standard therapy. Outcomes included the difference in the change (Δ) in total antioxidant capacity (TAC) and malondialdehyde (MDA), both assessed colorimetrically and left ventricular mass index (LVMI) assessed through transthoracic echocardiography. Results: Compared with the SOC, metformin treatment increased TAC [Δ = 0.12 mmol/L, confidence intervals (95% CIs): 0.03-0.21; P = 0.007]. TAC increased significantly only in the metformin group (0.90 ± 0.08 mmol/L at baseline vs. 1.04 ± 0.99 mmol/L at 6 months, P < 0.05). Metformin therapy preserved LVMI (Δ = -23 g/m2, 95% CI: -42.91 to -4.92; P = 0.014) and reduced fasting plasma glucose (Δ = -6.16, 95% CI: -12.31 to -0.02, P = 0.047) compared with the SOC. Results did not change after adjusting for baseline values. Changes in MDA left ventricular ejection fraction (LVEF) and blood pressure were not significantly different between groups. Conclusion: Metformin treatment in HF patients with reduced LVEF improved TAC and prevented the increase in LVMI compared with the SOC. These effects of metformin warrant further research in HF patients without diabetes to explore the potential benefits of metformin. Trial Registration Number: This protocol was registered in ClinicalTrials.gov under the number NCT05177588.

Angiotensin converting enzyme 2 gene expression and markers of oxidative stress are correlated with disease severity in patients with COVID-19

BACKGROUND

Oxidative stress is thought to play a significant role in the pathogenesis and severity of COVID-19. Additionally, angiotensin converting enzyme 2 (ACE2) expression may predict the severity and clinical course of COVID-19. Accordingly, the aim of the present study was to evaluate the association of oxidative stress and ACE2 expression with the clinical severity in patients with COVID-19.

METHODS AND RESULTS

The present study comprised 40 patients with COVID-19 and 40 matched healthy controls, recruited between September 2021 and March 2022. ACE 2 expression levels were measured using Hera plus SYBR Green qPCR kits with GAPDH used as an internal control. Serum melatonin (MLT) levels, serum malondialdehyde (MDA) levels, and total antioxidant capacity (TAC) were estimated using ELISA. The correlations between the levels of the studied markers and clinical indicators of disease severity were evaluated. Significantly, lower expression of ACE2 was observed in COVID-19 patients compared to controls. Patients with COVID-19 had lower serum levels of TAC and MLT but higher serum levels of MDA compared to normal controls. Serum MDA levels were correlated with diastolic blood pressure (DBP), Glasgow coma scale (GCS) scores, and serum potassium levels. Serum MLT levels were positively correlated with DBP, mean arterial pressure (MAP), respiratory rate, and serum potassium levels. TAC was correlated with GCS, mean platelet volume, and serum creatinine levels. Serum MLT levels were significantly lower in patients treated with remdesivir and inotropes. Receiver operating characteristic curve analysis demonstrates that all markers had utility in discriminating COVID-19 patients from healthy controls.

CONCLUSIONS

Increased oxidative stress and increased ACE2 expression were correlated with disease severity and poor outcomes in hospitalized patients with COVID-19 in the present study. Melatonin supplementation may provide a utility as an adjuvant therapy in decreasing disease severity and death in COVID-19 patients.

Total Antioxidant Capacity and Prediabetes Are Associated with Left Ventricular Geometry in Heart-Failure Patients with Reduced Ejection Fraction: A Cross-Sectional Study

Introduction: Few studies explored the association between total antioxidant capacity (TAC) and left ventricular (LV) geometry in patients with heart failure and reduced ejection fraction (HFrEF). The current study aimed to assess factors associated with LV geometry in HFrEF patients with particular emphasis on oxidative stress and glycemic status. Methods: A cross-sectional study was conducted from July 2021 to September 2022. All consecutive patients with HFrEF who were stabilized on optimal or maximally tolerated heart failure medications were recruited. Patients were classified into tertiles based on TAC and malondialdehyde for correlation with other parameters. Results: TAC was significantly associated with LV geometry (P = 0.01), with higher TAC levels observed in patients with normal LV geometry (0.95 ± 0.08) and concentric hypertrophy (1.01 ± 0.14) than in patients with eccentric hypertrophy (EH) (0.90 ± 0.10). There was a significant positive trend in the association between glycemic state and LV geometry (P = 0.002). TAC showed a statistically significant positive correlation with EF (r = 0.29, P = 0.0064) and a negative correlation with LV internal diameter at end diastole (r = -0.26, P = 0.014), LV mass index (r = -0.25, P = 0.016), and LV mass (r = -0.27, P = 0.009). After adjusting for multiple confounders, prediabetes [odds ratio (OR) = 4.19, P = 0.032] and diabetes (OR = 7.47, P = 0.008) were associated with higher odds of EH than normoglycemic patients. A significant inverse trend was also observed in the association between TAC tertile and the odds of LV geometry (OR = 0.51, P = 0.046). Conclusions: TAC and prediabetes are significantly associated with LV geometry. TAC can be used as an additional marker in HFrEF patients to reflect the severity of the disease. Interventions aimed at managing oxidative stress might be useful in HFrEF patients to reduce oxidative stress and improve LV geometry and quality of life. Trial Registration Number: This study is part of an ongoing randomized clinical trial (ClinicalTrials.gov identifier NCT05177588).

Balance of the prooxidant and antioxidant system is associated with mortality in critically ill patients

It is well known that oxidative stress causes certain diseases and organ damage. However, roles of oxidative stress in the acute phase of critical patients remain to be elucidated. This study aimed to investigate the balance of oxidative and antioxidative system and to clarify the association between oxidative stress and mortality in critically ill patients. This cohort study enrolled 247 patients transported to our emergency department by ambulance. Blood was drawn on hospital arrival, and serum derivatives of reactive oxidant metabolites (dROMs, oxidative index) and biological antioxidant potential (BAP, antioxidative index) were measured. Modified ratio (MR) is also calculated as BAP/dROMs/7.51. There were 197 survivors and 50 non-survivors. In the non-survivors, dROMs were significantly lower (274 vs 311, p<0.01), BAP was significantly higher (2,853 vs 2,138, p<0.01), and MR was significantly higher (1.51 vs 0.92, p<0.01) compared to those in the survivors. The AUC of MR was similar to that for the APACHE II score. Contrary to our expectations, higher BAP and lower dROMs were observed on admission in non-survivors. This may suggest that the antioxidative system is more dominant in the acute phase of severe insults and that the balance toward a higher antioxidative system is associated with mortality.

A low serum uric acid concentration predicts a poor prognosis in adult patients with candidemia

This study aimed to determine the relation of serum uric acid (UA) level with outcomes in adults with candidemia. Medical records of patients with candidemia treated from 2014 to 2017 were retrospectively reviewed. Patients were age- and sex-matched with healthy control subjects. The associations of UA and cystatin C (CysC) levels with diagnosis and prognosis of candidemia were determined. Sixty-four patients with candidemia (13 females and 51 males; mean age 48.5 years) and 64 matched control subjects were included. The median UA level of patients with candidemia was 255 μmol/L (range, 158–395 μmol/L), and of healthy controls was 398 μmol/L (range, 345–450 μmol/L) (P < 0.001). The median CysC level of patients with candidemia was 1.07 mg/L (range, 0.89–1.59 mg/L), and of the healthy controls was 0.82 mg/L (range, 0.74–0.95 mg/L) (P < 0.001). Patients with a favorable prognosis had significantly higher serum UA levels than those with a poor prognosis (181 μmol/L vs 344 μmol/L; P = 0.001). It was indicated that the estimated OR for UA was significantly > 1 (P = 0.009), and the AUC was 0.734. In summary, a lower serum UA level is associated with a diagnosis of candidemia, and a poor outcome.

Reduced Risk of Sepsis and Related Mortality in Chronic Kidney Disease Patients on Xanthine Oxidase Inhibitors: A National Cohort Study

Background

Advanced chronic kidney disease (CKD) patients are at higher risk of sepsis-related mortality following infection and bacteremia. Interestingly, the urate-lowering febuxostat and allopurinol, both xanthine oxidase inhibitors (XOis), have been suggested to influence the sepsis course in animal studies. In this study, we aim to investigate the relationship between XOis and infection/sepsis risk in pre-dialysis population.

Methods

Pre-dialysis stage 5 CKD patients with gout were identified through the National Health Insurance Research Database (NHIRD) in Taiwan from 2012 to 2016. Outcomes were also compared with national data.

Results

In our nationwide, population-based cohort study, 12,786 eligible pre-dialysis stage 5 CKD patients were enrolled. Compared to non-users, febuxostat users and allopurinol users were associated with reduced sepsis/infection risk [hazard ratio (HR), 0.93; 95% confidence interval (CI), 0.87–0.99; P = 0.0324 vs. HR, 0.92; 95% CI, 0.86–0.99; P = 0.0163]. Significant sepsis/infection-related mortality risk reduction was associated with febuxostat use (HR, 0.68; 95% CI, 0.52–0.87). Subgroup analysis demonstrated preference of febuxostat over allopurinol in sepsis/infection-related mortality among patients younger than 65 years of age, stain users, non-steroidal anti-inflammatory drug non-users, and non-diabetics. There was no significant difference in major adverse cardiac and cerebrovascular event (MACCE) risk between users and non-users while reduced risk of all-cause mortality was observed for XOi users.

Conclusions

Use of XOi in pre-dialysis stage 5 CKD patients may be associated with reduced risk of sepsis/infection and their related mortality without increased MACCE and overall mortality.

Oxidant/Antioxidant Status Is Impaired in Sepsis and Is Related to Anti-Apoptotic, Inflammatory, and Innate Immunity Alterations

Oxidative stress is considered pivotal in the pathophysiology of sepsis. Oxidants modulate heat shock proteins (Hsp), interleukins (IL), and cell death pathways, including apoptosis. This multicenter prospective observational study was designed to ascertain whether an oxidant/antioxidant imbalance is an independent sepsis discriminator and mortality predictor in intensive care unit (ICU) patients with sepsis (n = 145), compared to non-infectious critically ill patients (n = 112) and healthy individuals (n = 89). Serum total oxidative status (TOS) and total antioxidant capacity (TAC) were measured by photometric testing. IL-6, -8, -10, -27, Hsp72/90 (ELISA), and selected antioxidant biomolecules (Ζn, glutathione) were correlated with apoptotic mediators (caspase-3, capsase-9) and the central anti-apoptotic survivin protein (ELISA, real-time PCR). A wide scattering of TOS, TAC, and TOS/TAC in all three groups was demonstrated. Septic patients had an elevated TOS/TAC, compared to non-infectious critically ill patients and healthy individuals (p = 0.001). TOS/TAC was associated with severity scores, procalcitonin, IL-6, -10, -27, IFN-γ, Hsp72, Hsp90, survivin protein, and survivin isoforms -2B, -ΔΕx3, -WT (p < 0.001). In a propensity probability (age-sex-adjusted) logistic regression model, only sepsis was independently associated with TOS/TAC (Exp(B) 25.4, p < 0.001). The AUC_TOS/TAC (0.96 (95% CI = 0.93–0.99)) was higher than AUC_TAC (z = 20, p < 0.001) or AUC_TOS (z = 3.1, p = 0.002) in distinguishing sepsis. TOS/TAC, TOS, survivin isoforms -WT and -2B, Hsp90, IL-6, survivin protein, and repressed TAC were strong predictors of mortality (p < 0.01). Oxidant/antioxidant status is impaired in septic compared to critically ill patients with trauma or surgery and is related to anti-apoptotic, inflammatory, and innate immunity alterations. The unpredicted TOS/TAC imbalance might be related to undefined phenotypes in patients and healthy individuals.

Prognostic value of hyperuricemia for patients with sepsis in the intensive care unit

This study evaluated the relationship between hyperuricemia at admission and the clinical prognosis of patients with sepsis. The data were obtained from the Intensive Care Medical Information Database III. The patients were divided into a normal serum uric acid group and a hyperuricemia group. The main outcome was 90-day mortality, and the secondary outcomes were hospital mortality, 30-day mortality, and acute kidney injury. Propensity score matching was used to balance the baseline characteristics of the groups. Our study retrospectively included 954 patients. Before and after propensity score matching, the incidence of AKI, the 30-day and 90-day mortality rates were significantly higher in the hyperuricemia group. Cox regression analysis showed that hyperuricemia was significantly associated with 90-day mortality (HR 1.648, 95% CI 1.215–2.234, p = 0.006), and hyperuricemia was significantly associated with the incidence of AKI (HR 1.773, 95% CI 1.107–2.841, p = 0.017). The Kaplan–Meier survival curve showed that the 90-day survival rate was significantly lower in the hyperuricemia group. In patients with sepsis in the intensive care unit, hyperuricemia was significantly associated with increased risk 90-day all-cause mortality and the incidence of AKI.

Plasmalogen Loss in Sepsis and SARS-CoV-2 Infection

Plasmalogens are plasma-borne antioxidant phospholipid species that provide protection as cellular lipid components during cellular oxidative stress. In this study we investigated plasma plasmalogen levels in human sepsis as well as in rodent models of infection. In humans, levels of multiple plasmenylethanolamine molecular species were decreased in septic patient plasma compared to control subject plasma as well as an age-aligned control subject cohort. Additionally, lysoplasmenylcholine levels were significantly decreased in septic patients compared to the control cohorts. In contrast, plasma diacyl phosphatidylethanolamine and phosphatidylcholine levels were elevated in septic patients. Lipid changes were also determined in rats subjected to cecal slurry sepsis. Plasma plasmenylcholine, plasmenylethanolamine, and lysoplasmenylcholine levels were decreased while diacyl phosphatidylethanolamine levels were increased in septic rats compared to control treated rats. Kidney levels of lysoplasmenylcholine as well as plasmenylethanolamine molecular species were decreased in septic rats. Interestingly, liver plasmenylcholine and plasmenylethanolamine levels were increased in septic rats. Since COVID-19 is associated with sepsis-like acute respiratory distress syndrome and oxidative stress, plasmalogen levels were also determined in a mouse model of COVID-19 (intranasal inoculation of K18 mice with SARS-CoV-2). 3 days following infection, lung infection was confirmed as well as cytokine expression in the lung. Multiple molecular species of lung plasmenylcholine and plasmenylethanolamine were decreased in infected mice. In contrast, the predominant lung phospholipid, dipalmitoyl phosphatidylcholine, was not decreased following SARS-CoV-2 infection. Additionally total plasmenylcholine levels were decreased in the plasma of SARS-CoV-2 infected mice. Collectively, these data demonstrate the loss of plasmalogens during both sepsis and SARS-CoV-2 infection. This study also indicates plasma plasmalogens should be considered in future studies as biomarkers of infection and as prognostic indicators for sepsis and COVID-19 outcomes.

LBP Protects Hepatocyte Mitochondrial Function Via the PPAR-CYP4A2 Signaling Pathway in a Rat Sepsis Model

OBJECTIVES

To explore the role of LPS binding protein (LBP) in metabolism and optimize sepsis treatment.

DESIGN

A sepsis model was established by injecting LPS into LBP-/- rats and WT rats and observing changes in the liver over time (0, 1, 6, and 24 h).

SETTING

Detecting liver inflammation and injury. Optimizing the treatment of sepsis.

SUBJECTS

WT rats and LBP-/- rats.

INTERVENTIONS

We established a sepsis model by injecting LPS intravenously.

MEASUREMENTS AND MAIN RESULTS

First, we induced sepsis in WT and LBP-/- rats with LPS. The rats were sacrificed, and serum and liver samples were collected at 1, 6, and 24 h after LPS injection. We found that the deletion of LBP reduced LPS-induced liver inflammation and injury at 1 and 6 h. Ballooning degeneration was clearly present in LBP-/- rat livers at 24 h after LPS injection. We found that mitochondrial damage and reactive oxygen species (ROS) levels were higher in LBP-/- rat livers than in WT rat livers at 24 h after LPS injection. According to the transcriptomic results, the peroxisome proliferator-activated receptor (PPAR) pathway may be the reason for lesions in LBP-/- rats. To further investigate the function of PPARα in sepsis, we inhibited mTOR with rapamycin and examined mitochondrial injury and ROS levels. The levels of mitochondrial damage and ROS were reduced after LBP-/- rats were pretreated with rapamycin in the context of LPS-induced sepsis. Inhibiting CYP4a2, one of the PPARα-target gene products, reduced the level of LPS-induced ROS in LBP-/- rats.

CONCLUSION

LBP protects hepatic mitochondria against LPS-induced damage via the LBP-PPARα-CYP4a2 signaling pathway.

Profiling serum levels of glutathione reductase and interleukin-10 in positive and negative-PCR COVID-19 outpatients: A comparative study from southwestern Iran

Since the outbreak of COVID-19 in China, it has rapidly spread across many other countries. We evaluated antioxidant defense systems and inflammatory status related to the SARS-CoV2 infection in a population from southwestern Iran. Comorbidities and clinical symptoms of 104 subjects (comprising negative and positive-PCR COVID-19 outpatients) were assessed. Serum concentrations of glutathione reductase (GR) and interleukin-10 (IL-10) were measured using ELISA. In the positive-PCR group, follow-ups on clinical symptoms were carried out for 28 days at 7-day intervals. In the positive-PCR group, hypertension, diabetes, liver disease, chronic heart disease, and chronic kidney disease were the most common comorbidities. In the general category of symptoms, we found a significant difference between negative and positive-PCR groups, except regarding runny noses. In the pulmonary category, there was a significant difference between the two groups except in terms of chest pain. We also determined a significant difference in neurologic symptoms, except for ear pain, between negative and positive-PCR groups. We also found significantly lower levels of GR but higher levels of IL-10 in the positive-PCR group (p = 0.000 for both). In the positive-PCR group, serum levels of IL-10 (odds ratio = 0.914, p = 0.012) decreased the chances of neurological symptoms occurring over time. The antioxidant defense systems of positive-PCR outpatients failed as demonstrated by a reduction in the serum levels of GR. We also indicated a dysregulation in the immune response against COVID-19, characterized by changes in serum IL-10 levels.

Peroxiredoxin AhpC1 protects Pseudomonas aeruginosa against the inflammatory oxidative burst and confers virulence

Pseudomonas aeruginosa is an opportunistic bacterium in patients with cystic fibrosis and hospital acquired infections. It presents a plethora of virulence factors and antioxidant enzymes that help to subvert the immune system. In this study, we identified the 2-Cys peroxiredoxin, alkyl-hydroperoxide reductase C1 (AhpC1), as a relevant scavenger of oxidants generated during inflammatory oxidative burst and a mechanism of P. aeruginosa (PA14) escaping from killing. Deletion of AhpC1 led to a higher sensitivity to hypochlorous acid (HOCl, IC₅₀ 3.2 ± 0.3 versus 19.1 ± 0.2 μM), hydrogen peroxide (IC₅₀ 91.2 ± 0.3 versus 496.5 ± 6.4 μM) and the organic peroxide urate hydroperoxide. ΔahpC1 strain was more sensitive to the killing by isolated neutrophils and less virulent in a mice model of infection. All mice intranasally instilled with ΔahpC1 survived as long as they were monitored (15 days), whereas 100% wild-type and ΔahpC1 complemented with ahpC1 gene (ΔahpC1 attB:ahpC1) died within 3 days. A significantly lower number of colonies was detected in the lung and spleen of ΔahpC1-infected mice. Total leucocytes, neutrophils, myeloperoxidase activity, pro-inflammatory cytokines, nitrite production and lipid peroxidation were much lower in lungs or bronchoalveolar liquid of mice infected with ΔahpC1. Purified AhpC neutralized the inflammatory organic peroxide, urate hydroperoxide, at a rate constant of 2.3 ± 0.1 × 10⁶ M^-1s^-1, and only the ΔahpC1 strain was sensitive to this oxidant. Incubation of neutrophils with uric acid, the urate hydroperoxide precursor, impaired neutrophil killing of wild-type but improved the killing of ΔahpC1. Hyperuricemic mice presented higher levels of serum cytokines and succumbed much faster to PA14 infection when compared to normouricemic mice. In summary, ΔahpC1 PA14 presented a lower virulence, which was attributed to a poorer ability to neutralize the oxidants generated by inflammatory oxidative burst, leading to a more efficient killing by the host. The enzyme is particularly relevant in detoxifying the newly reported inflammatory organic peroxide, urate hydroperoxide.

Glutathione Reductase Is Associated with the Clinical Outcome of Septic Shock in the Patients Treated Using Continuous Veno-Venous Haemofiltration

Background and objectives: At present, there is insufficient evidence to support the use of continuous veno-venous haemofiltration (CVVH) in the early treatment of septic shock. This study focuses on the association between survival and different parameters of oxidative stress (RedOx). Thereby, we evaluated whether RedOx markers are associated with the outcome of septic shock in patients under early-initiated CVVH treatment. Materials and Methods: We conducted a prospective observational study of 65 patients with septic shock who started CVVH within 12 h after hospital admission. Blood samples were taken from each patient prior to the start of CVVH. The following RedOx markers were measured: glutathione peroxidase, glutathione reductase (GR), total antioxidant capacity, superoxide dismutase, nitric oxide, malondialdehyde and 4-hydroxynonenal. The odds ratio (OR) was calculated using binary logistic regression and stepwise multivariable regression. Results: The 65 patients had a median age of 66 years and 39 were male. Based on the outcome, the patients were divided into two groups—non-survivors (n = 29) and survivors (n = 36)—and the levels of RedOx markers were compared between them. Of all the markers, only higher GR activity was found to be significantly associated with the fatal outcome; 100.3 U/L versus 60.5 U/L, OR = 1.027 (95% CI, 1.010–1.044). Following adjustment for the sequential organ failure assessment score and other parameters, GR activity still presented a significant association with the fatal outcome, OR = 1.020 (95% CI, 1.002–1.038). Conclusions: GR activity is associated with in-hospital fatal outcomes among septic shock patients under early-initiated CVVH treatment. Septic shock patients who have a lower GR activity at hospital admission may have a favourable outcome of the early initiation of CVVH.

Energetic dysfunction in sepsis: a narrative review

Background

Growing evidence associates organ dysfunction(s) with impaired metabolism in sepsis. Recent research has increased our understanding of the role of substrate utilization and mitochondrial dysfunction in the pathophysiology of sepsis-related organ dysfunction. The purpose of this review is to present this evidence as a coherent whole and to highlight future research directions.

Main text

Sepsis is characterized by systemic and organ-specific changes in metabolism. Alterations of oxygen consumption, increased levels of circulating substrates, impaired glucose and lipid oxidation, and mitochondrial dysfunction are all associated with organ dysfunction and poor outcomes in both animal models and patients. The pathophysiological relevance of bioenergetics and metabolism in the specific examples of sepsis-related immunodeficiency, cerebral dysfunction, cardiomyopathy, acute kidney injury and diaphragmatic failure is also described.

Conclusions

Recent understandings in substrate utilization and mitochondrial dysfunction may pave the way for new diagnostic and therapeutic approaches. These findings could help physicians to identify distinct subgroups of sepsis and to develop personalized treatment strategies. Implications for their use as bioenergetic targets to identify metabolism- and mitochondria-targeted treatments need to be evaluated in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00893-7.

Blood thiamine (vitamin B1 ), ascorbic acid (vitamin C), and cortisol concentrations in healthy and ill neonatal foals

Background

Sepsis is common in foals and several treatments are used to facilitate recovery. Evidence in people suggests an association between low blood concentrations of thiamine, ascorbic acid, and cortisol and sepsis, with further evidence suggesting that administration of hydrocortisone, thiamine, and ascorbic acid may improve outcome. No information is available with regard to these treatments in foals.

Hypothesis/Objectives

To compare blood concentrations of thiamine, ascorbic acid, and cortisol in healthy and ill foals.

Animals

Fifteen healthy and 27 ill (septic and sick‐nonseptic [SNS]) foals were evaluated at admission. Fewer healthy and ill foals were available for sampling at 72 and 120 hours.

Methods

Prospective study. Blood was collected from healthy foals at 12 (n = 15), 72 (n = 11), and 120 (n = 9) hours of age and from ill foals <48 hours old at admission (n = 27), 72 (n = 8), and 120 (n = 8) hours after presentation. Thiamine, ascorbic acid, and cortisol concentrations were measured in blood samples and compared between groups of foals.

Results

Blood concentrations of thiamine were significantly lower in septic compared to healthy foals at 72 (median, 1.72 ng/mL; P = .02) and 120 (median, 2.0 ng/mL; P = .04) hours after admission; blood concentrations of ascorbic acid also were significantly lower in septic compared to healthy foals at 72 (median, 4.4 μg/mL; P = .02) and 120 hours (median, 4.8 μg/mL; P = .03). Blood concentrations of ascorbic acid were lower in SNS compared to healthy foals at 72 (median, 6.9 μg/mL; P = .03) and 120 (median, 6.4 μg/mL; P = .04) hours after admission. Serum cortisol concentrations were significantly higher at admission in septic (median, 4.23 μg/dL) compared to SNS (median, 1.8 μg/dL; P = .01) and healthy (median, 2.2 μg/dL; P = .002) foals.

Conclusions and Clinical Importance

A potential association exists between illness in foals and lower blood concentrations of thiamine and ascorbic acid during hospitalization. Additional studies are needed to examine a larger population of foals and determine the clinical impact of low vitamin concentrations, if any, on morbidity and mortality.

Divergent trajectories of cellular bioenergetics, intermediary metabolism and systemic redox status in survivors and non-survivors of critical illness

Background

Numerous pathologies result in multiple-organ failure, which is thought to be a direct consequence of compromised cellular bioenergetic status. Neither the nature of this phenotype nor its relevance to survival are well understood, limiting the efficacy of modern life-support.

Methods

To explore the hypothesis that survival from critical illness relates to changes in cellular bioenergetics, we combined assessment of mitochondrial respiration with metabolomic, lipidomic and redox profiling in skeletal muscle and blood, at multiple timepoints, in 21 critically ill patients and 12 reference patients.

Results

We demonstrate an end-organ cellular phenotype in critical illness, characterized by preserved total energetic capacity, greater coupling efficiency and selectively lower capacity for complex I and fatty acid oxidation (FAO)-supported respiration in skeletal muscle, compared to health. In survivors, complex I capacity at 48 h was 27% lower than in non-survivors (p = 0.01), but tended to increase by day 7, with no such recovery observed in non-survivors. By day 7, survivors’ FAO enzyme activity was double that of non-survivors (p = 0.048), in whom plasma triacylglycerol accumulated. Increases in both cellular oxidative stress and reductive drive were evident in early critical illness compared to health. Initially, non-survivors demonstrated greater plasma total antioxidant capacity but ultimately higher lipid peroxidation compared to survivors. These alterations were mirrored by greater levels of circulating total free thiol and nitrosated species, consistent with greater reductive stress and vascular inflammation, in non-survivors compared to survivors. In contrast, no clear differences in systemic inflammatory markers were observed between the two groups.

Conclusion

Critical illness is associated with rapid, specific and coordinated alterations in the cellular respiratory machinery, intermediary metabolism and redox response, with different trajectories in survivors and non-survivors. Unravelling the cellular and molecular foundation of human resilience may enable the development of more effective life-support strategies.

U-Shaped Association Between Serum Uric Acid and Short-Term Mortality in Patients With Infective Endocarditis

BACKGROUND

Increased uric acid (UA) levels have been reported to be associated with poor clinical outcomes in several conditions. However, the prognostic value of UA in patients with infective endocarditis (IE) is yet unknown.

METHODS

A total of 1,117 patients with IE were included and divided into two groups according to the current definition of hyperuricemia (UA>420 μmol/L in men and >360 μmol/L in women): hyperuricemia group (n=336) and normouricemia group (n=781). The association between the UA level and short-term outcomes were examined.

RESULTS

The in-hospital mortality was 6.2% (69/1117). Patients with hyperuricemia carried a higher risk of in-hospital death (9.8% vs. 4.6%, p=0.001). Hyperuricemia was not an independent risk factor for in-hospital death (adjusted odds ratio [aOR]=1.92, 95% confidence interval [CI]: 0.92-4.02, p=0.084). A U-shaped relationship was found between the UA level and in-hospital death (p<0.001). The in-hospital mortality was lower in patients with UA in the range 250-400 μmol/L. The aOR of in-hospital death in patients with UA>400 and <250 μmol/L was 3.48 (95% CI: 1.38-8.80, p=0.008) and 3.28 (95%CI: 1.27-8.51, p=0.015), respectively. Furthermore, UA>400 μmol/L (adjusted hazard ratio [aHR]=3.54, 95%CI: 1.77-7.07, p<0.001) and <250 μmol/L (aHR=2.23, 95%CI: 1.03-4.80, p=0.041) were independent risk factors for the 6-month mortality.

CONCLUSION

The previous definition of hyperuricemia was not suitable for risk assessment in patients with IE because of the U-shaped relationship between UA levels and in-hospital death. Low and high levels of UA were predictive of increased short-term mortality in IE patients.

Fibroblast growth factor 21 is associated with increased serum total antioxidant capacity and oxidized lipoproteins in humans with different stages of chronic kidney disease

BACKGROUND AND AIMS

Oxidative stress (OS) induces the production of fibroblast growth factor 21 (FGF21). Previous data have revealed that FGF21 protects cells from OS injury and death, making it a potential therapeutic option for many diseases with increased OS. However, the association of this growth factor with OS markers in humans with chronic kidney disease (CKD) remains unknown. This study aims to evaluate the association of serum FGF21 with serum total antioxidant capacity (TAC) and oxidized low-density lipoproteins (OxLDL) in subjects in different stages of kidney disease.

METHODS

This is a cross-sectional study that included 382 subjects with different stages of CKD, irrespective of type 2 diabetes (T2D) diagnosis. Associations of serum FGF21 with OxLDL, TAC, sex, age, body mass index (BMI), fasting plasma glucose, estimated glomerular filtration rate (eGFR), T2D, and smoking, were evaluated through bivariate and partial correlation analyses. Independent associations of these variables with serum FGF21 were evaluated using multiple linear regression analysis.

RESULTS

Serum FGF21 was significantly and positively correlated with age (r = 0.236), TAC (lnTAC) (r = 0.217), and negatively correlated with eGFR (r = -0.429) and male sex (r = -0.102). After controlling by age, sex, BMI, T2D, smoking, and eGFR; both TAC and OxLDL were positively correlated with FGF21 (r = 0.117 and 0.158 respectively, p < 0.05). Using multiple linear regression analysis, eGFR, male sex, T2D, OxLDL, and TAC were independently associated with serum FGF21 (STDβ = -0.475, 0.162, -0.153, 0.142 and 0.136 respectively; p < 0.05 for all) adjusted for age, BMI, smoking, and fasting plasma glucose.

CONCLUSION

A positive association between serum FGF21 and OS has been found independently of renal function in humans. Results from the present study provide novel information for deeper understanding of the role of FGF21 in OS in humans with CKD and T2D; mechanistic studies to explain the association of serum FGF21 with oxidative stress in CKD are needed.

Relationship between serum 25-hydroxyvitamin D, total antioxidant capacity and pneumonia incidence, severity and outcome in Nigerian children

Background

The pathologic basis of childhood community-acquired pneumonia (CAP) involves the generation of reactive oxygen species by immune cells leading to cellular damage and lung congestion. Serum antioxidants and vitamin D with immunomodulatory properties therefore hold prospects in the prevention and management of pneumonia in children. This case–control study set out to compare the serum 25-hydroxyvitamin D (25-OHD) and total antioxidant capacity (TAC) in Nigerian children with CAP and age- and sex-matched controls and to relate these parameters with pneumonia severity and outcome—length of hospital stay (LOH).

Results

A total of 160 children (80 each for CAP and controls) were recruited. The median (IQR) age was 1.8 (0.6–4.0) years, male:female 1.7:1, 63 (78.8%) and 11 (13.8%) of CAP group had severe pneumonia and parapneumonic effusions, respectively. Serum 25-OHD (33.8 (18.3) ng/ml vs. 41.9 (12.3) ng/ml; p = 0.010) and TAC (6.1 (4.4–8.1) ng/dl vs. 7.2 (4.7–17.5) ng/dl; p = 0.023) were lower in children with CAP than controls. Lower serum 25-OHD was observed in severe than non-severe pneumonia (30.5(17.1) ng/ml vs. 46.3 (17.6) ng/ml; p = 0.001) but LOH did not correlate with serum 25-OHD and TAC.

Conclusion

Children with CAP had lower serum vitamin D and antioxidants than controls, and severe pneumonia was significantly associated with suboptimal serum vitamin D. They however were not related to pneumonia outcome. Optimal serum vitamin D and antioxidants may play a role in reducing the incidence of childhood CAP in Nigerian children.

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia

Background

Paraoxonase-1 (PON-1) is an antioxidant enzyme, whose activity decreases during the acute phase response in many species. Little is known about PON-1 and its role as a negative acute phase protein during septic inflammation in horses, but promising findings about its utility in diagnosing SIRS and predicting the outcome in diseased horses, were recently highlighted. The objective of the study was to investigate the behaviour of PON-1 in horses after experimentally induced endotoxemia. To this aim, PON-1 activity was measured on 66 plasma samples collected from six clinically healthy mares, previously included in another study, before and at multiple time points between 12 and 240 h after intravenous infusion of Escherichia coli O55:B5 lipopolysaccharide (LPS).

Results

Compared with baseline values, a progressive transient decrease of PON-1 activity was observed starting from 24 h post-infusion, with lowest values observed between 3 to 7 days post-infusion, followed by a normalisation to pre-infusion levels the tenth day.

Conclusions

The results of this study suggest that measurement and monitoring of PON-1 activity might be useful to evaluate progression and recovery from endotoxemia in horses. Further studies in horses with naturally occurring sepsis are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02629-4.

Serum irisin levels are decreased in patients with sepsis, and exogenous irisin suppresses ferroptosis in the liver of septic mice

BACKGROUND

Sepsis remains a major health issue without an effective therapy. Ferroptosis, an iron-dependent programmed cell death, has been proposed to be related to the pathogenesis of sepsis. Irisin, a myokine released during exercise, improves mitochondrial function under various conditions. Ferroptosis is closely related to mitochondrial function. However, the role of irisin in sepsis-induced ferroptosis and mitochondrial dysfunction in the liver remained unknown. Thus, we hypothesize that irisin treatment suppresses ferroptosis and improves mitochondrial function in sepsis.

METHODS

To study this, we first explored the role of serum irisin levels in patients with sepsis, and then determined the effect of irisin administration on ferroptosis and mitochondrial function in the liver of septic mice.

RESULTS

Serum irisin levels were decreased and negatively correlated with the APACHE II scores in patients with sepsis. In mice subjected to cecal ligation and puncture (CLP), exogenous irisin administration suppressed ferroptosis, inhibited inflammatory response, decreased reactive oxygen species (ROS) production, restored abnormal mitochondrial morphology, and increased mtDNA copy number and adenosine triphosphate (ATP) content. The effect of irisin on ferroptosis was confirmed in LPS-treated hepatocytes and CLP-induced septic mice. Inhibition of glutathione peroxidase 4 (GPX4), a central regulator of ferroptosis, reduced irisin's protective effects in LPS-treated hepatocytes and CLP-induced septic mice, while blocking the irisin receptor with RGD peptide or Echistain decreased irisin-induced GPX4 expression.

CONCLUSIONS

Serum irisin levels are decreased and negatively correlated with disease severity in patients with sepsis, and irisin treatment suppresses ferroptosis and restores mitochondrial function in experimental sepsis. Irisin may offer therapeutic potential in the management of sepsis.

Effect of serum uric acid level and Multinational Association for Supportive Care in Cancer risk score on febrile neutropenia mortality

PURPOSE

The study was aimed to evaluate the effect of uric acid (UA) on the 30-day mortality of patients admitted to the tertiary referral hospital with a complaint of febrile neutropenia (FEN). The secondary aim was to evaluate the use of combining serum UA levels with the Multinational Association for Supportive Care in Cancer (MASCC) risk score.

METHODS

A retrospective study in which the MASCC score and serum UA levels were used to evaluate the mortality risk within 30 days among patients with FEN.

RESULTS

A total of 118 FEN episodes were included in the study and 17 (14%) of these patients died. While this rate is 23% in the high-risk group according to the MASCC score, it is 7% in the low-risk group (p = 0.011). In multivariate analysis of the parameters that significantly affect the 30-day FEN mortality, MASCC risk score (OR, 4.28; CI 95% 1.19-15.39, p = 0.013) and having a level of serum UA > 7 mg/dL (OR, 4.46; CI 95% 1.19-15.38, p = 0.032) was significantly increased the risk of in 30-day mortality of FEN. The rate of 30-day mortality of FEN was 0% in patients with a low MASCC risk score and UA level compared with 50% in the high MASCC risk score and high UA level group, and the difference was statistically significant (p < 0.001).

CONCLUSION

Increased level of UA at the time of FEN diagnosis was independently associated with an increased rate of 30-day mortality of FEN. The combination of the MASCC risk score and serum UA level might thoroughly predict the 30-day mortality of FEN.

Serum Uric Acid Level in Relation to Severity of the Disease and Mortality of Critically Ill Patients

Aim:

This study was conducted to evaluate the validity of serum uric acid (UA) in prediction of mortality among patients in the emergency department.

Materials and Methods:

This is a prospective cohort study which was conducted during 2014. In this study, 120 critically ill patients who required Intensive Care Unit care services were included. For evaluation of severity of the disease, mortality in emergency department score (MEDS) in the first 24 h of admission, the requirement of using mechanical ventilation, taking vasopressor during the hospitalization time and severity of the disease based on MEDS score were measured. The patients were divided into two groups: Patients with serum UA level lower than 7.3 mg/dl and patients with serum UA level of equal or more than 7.3 mg/dl. For comparison of the mortality rate in groups, Chi-square and fisher exact tests were applied.

Results:

In patients, who needed mechanical ventilation, average of serum UA was 7.82 ± 2.82; however, in the patients who did not need mechanical ventilation this amount was 6.16 ± 2.7, a difference was statically significant. We found a statically meaningful difference between serum UA level with requiring mechanical ventilation and the predictive level of UA 6.95 ± 0.73 (F = 8.52; P ≤ 0.004). In the evaluation of MEDS, most patients with serum UA levels lower than 7.3 mg/dl had lower MEDS points (on average 4.6 ± 3.21) in compared to patients with serum UA level higher than 7.3 mg/dl (on average 12 ± 2.99). This difference was found to be statistically significant which indicates the patients whose serum UA was 7.3 mg/dl or higher, were at higher risk of mortality.

Conclusion:

The serum UA level in the 1^st day of hospitalization of a critically ill patient is not an independent indicative factor in relation to mortality. High level of UA reveals critical status of the patient and requires mechanical ventilation.

Melatonin for the treatment of sepsis: the scientific rationale

Sepsis affects 30 million people worldwide, leading to 6 million deaths every year (WHO), and despite decades of research, novel initiatives are drastically needed. According to the current literature, oxidative imbalance and mitochondrial dysfunction are common features of septic patients that can cause multiorgan failure and death. Melatonin, alongside its traditionally accepted role as the master hormonal regulator of the circadian rhythm, is a promising adjunctive drug for sepsis through its anti-inflammatory, antiapoptotic and powerful antioxidant properties. Several animal models of sepsis have demonstrated that melatonin can prevent multiorgan dysfunction and improve survival through restoring mitochondrial electron transport chain (ETC) function, inhibiting nitric oxide synthesis and reducing cytokine production. The purpose of this article is to review the current evidence for the role of melatonin in sepsis, review its pharmacokinetic profile and virtual absence of side effects. While clinical data is limited, we propose the adjunctive use of melatonin is patients with severe sepsis and septic shock.

Prognostic Value of Oxidative Stress Markers in Patients with Pulmonary Arterial or Chronic Thromboembolic Pulmonary Hypertension

Oxidative stress is regarded to play a crucial role in the pathophysiology of pulmonary arterial hypertension (PAH) and inoperable chronic thromboembolic pulmonary hypertension (CTEPH). This study evaluated the prognostic value of serum oxidative stress markers (malondialdehyde (MDA), total antioxidant capacity (TAC), catalase activity (CAT), and superoxide activity (SOD)) in patients with PAH and CTEPH (n = 45). During 13 months of follow-up (median 9 months), clinical deterioration occurred in 14 patients (including 2 deaths). On the Cox regression analysis, MDA, TAC, and CAT were associated with clinical deterioration (p = 0.0068, HR = 1.42, 95% CI: 1.10-1.82; p = 0.0038, HR = 0.033, 95% CI: 0.0032-0.33; and p = 0.046, HR = 0.20, 95% CI: 0.04-0.98, respectively). There was no significant difference in SOD (p = 0.53, HR = 0.97, 95% CI: 0.87-1.08). The cut-off value derived from ROC curve analysis was 3.79 μM (p = 0.0048, AUC = 0.76, 95% CI: 0.62-0.91) for MDA, 0.49 mM (p = 0.027, AUC = 0.71, 95% CI: 0.18-0.47) for TAC, and 1.34 U/L (p = 0.029, AUC = 0.71, 95% CI: 0.55-0.86) for CAT. MDA in the group with deterioration was higher (p = 0.0041), while TAC as well as CAT were lower (p = 0.027 and p = 0.028, respectively) when compared to stable patients. Survival without clinical deterioration was significantly longer in patients with lower MDA (p = 0.037, HR = 0.37, 95% CI: 0.12-1.14, log-rank), higher TAC (p = 0.0018, HR = 0.19, 95% CI: 0.06-0.60, log-rank), and higher CAT (p = 0.044, HR = 0.31 95% CI: 0.11-0.88, log-rank). Markers of oxidative stress such as MDA, TAC, and CAT were associated with adverse clinical outcomes in patients with PAH and inoperable or residual CTEPH.

Determination of Melatonin Deprivation Impact on Sepsis With Acute Phase Reactants

BACKGROUND

The aim of the present study is to determine the association of melatonin hormone level on CRP, Total Antioxidant Status, Leukocyte, Procalcitonin, and Malondialdehyde, all acute phase reactants in the dark and light cycle of rats with sepsis model.

MATERIALS AND METHODS

In this study, 54 rats were divided into three groups. Whereas the first and third groups had a 12 h dark-light cycle, the second group was exposed to light for 24 h at 21°C-22°C for 10 d without any water and food restrictions. In the second and third groups, sepsis model was formed by cecal ligation and puncture (CLP) method at the end of 10th day, and blood samples were taken at the end of the 10th day. C-reactive protein, Malondialdehyde, Procalcitonin in the blood samples were analyzed by ELISA, and the levels of Total Antioxidant Status and leukocyte were determined by colorimetric method in the subsequent 12 and 24 h.

RESULTS

CRP values increased in the second group rats, which were kept continuously under light and had undergone CLP, from 288.8 mg/L to 584.0 mg/L at the end of the 12 h and the end of the 24 h, approximately, two times. In rats, which were kept under 12 h of light, 12 h of darkness, and applied CLP (group 3), these values increased from 416.9 to 619.1; an increase of 1.5 times. When assessed for MDA, it was determined that the differences between Group 2 and Group 3 were more prominent between 0 h and 12 h. While the MDA values in group 2 increased from 16.53 nmol/mL at the 12 h to 17.66 nmol/mL at the 24 h. However, MDA values did not yield statistically significant changes in the third group. Changes in the in PCT values were similar to the MDA values obtained. Increase coefficient of the PCT values between 0 h and 12 h in the second group 2 was 1.26; however, in the third group, it was negligible.

CONCLUSIONS

An increase in the oxidative stress was observed in the rats that underwent CLP and melatonin deprivation via continuous 24 h light exposure for 10 d. Accordingly, deprivation of light is considered to be effective in sepsis treatment due to the increase in melatonin levels in intensive care unit patients.

The diagnostic and prognostic value of paraoxonase-1 and butyrylcholinesterase activities compared with acute-phase proteins in septic dogs and stratified by the acute patient physiologic and laboratory evaluation score

BACKGROUND

Sepsis is a complex syndrome that involves an increased oxidative stress status and dysregulation of cholinergic neurotransmission. Paraoxonase-1 (PON-1) and butyrylcholinesterase (BChE) activities have been identified as significant biomarkers to monitor such disorders in human septic patients.

OBJECTIVE

We aimed to determine the diagnostic and prognostic value of PON-1 and BChE vs other traditional acute-phase proteins such as albumin (ALB) and C-reactive protein (CRP) in septic dogs.

METHODS

This prospective observational study included 20 dogs with a diagnosis of sepsis, 27 with low-grade systemic inflammation (LGSI), and 10 healthy dogs that served as controls. Plasma samples were obtained from all dogs for analysis on admission, and then every 24-48 hours until discharge or death in the septic group.

RESULTS

Dogs with sepsis had lower PON-1 activity compared with dogs in the LGSI group (1.1 ± 0.10 vs 1.6 ± 0.08 U/mL, P = .002), but no differences in BChE activity were detected between the groups. PON-1, ALB, and CRP could successfully discriminate healthy animals from those with sepsis looking at the area under the curve (AUC) of the receiver operator characteristics curves (ROCs), which were 0.828, 0.903 and 1.000, respectively. Finally, although no differences were found among the groups for PON-1 or BChE activity, the nonsurvivor septic dogs had higher CRP (P = .002), lower ALB (P = .025) levels, and tended to have lower PON-1 (P = .082) activities than the survivors at patient death or discharge.

CONCLUSION

Septic dogs showed lower plasma PON-1 and higher BChE activities, but only PON-1 activity correlated with disease severity. Further studies are warranted to describe the usefulness of these new biomarkers of sepsis progression and recovery in dogs.

Comparison of Oxidative Stress Parameters in Heart Failure Patients Depending on Ischaemic or Nonischaemic Aetiology

Background

Abnormalities in the oxidative and antioxidant states causing oxidative stress were both found in heart failure (HF) of various aetiologies and atherosclerosis.

Aim of Study

The goals of the study were as follows: comparison of oxidative stress parameters (OSP) in ischaemic cardiomyopathy (ICM) (n = 479) and nonischaemic cardiomyopathy (nICM) (n = 295) patients; assessment of the relationships of OSP with functional capacity (NYHA class), maximal oxygen consumption (max.O2), left ventricle ejection fraction (LVEF), and NT-proBNP concentration; and determination of the mutual relations of OSP in subgroups of patients with ICM and n-ICM.

Methods

Serum concentrations of total antioxidant capacity (TAC), total oxidant status (TOS), uric acid (UA), bilirubin, albumin, protein sulfhydryl groups (PSH), and malondialdehyde (MDA) were measured. The oxidative stress index (OSI) and MDA/PSH ratio were calculated.

Results

Higher concentrations of TAC (1.14 vs 1.11 mmol/l; p < 0.001) and MDA (1.80 vs 1.70 μmol/l; p < 0.05) and higher MDA/PSH ratios (0.435 vs 0.358; p < 0,001) were observed in ICM than in nICM patients. Simultaneously, lower values of the OSI index (4.27 vs 4.6; p < 0, 05), PSH (4.10 vs 4.75 μmol/g of protein; p < 0,001), and bilirubin (12.70 vs 15.40 μmol/l; p < 0,001) concentrations were indicated in ICM patients. There were no differences in TOS, UA, and albumin between the examined groups. The NYHA class and VO2max correlate with MDA, bilirubin, and albumin in both groups, while with UA only in the ICM group. Correlations between the NYHA class, VO2max, and PSH were indicated in nICM. The association of LVEF with UA, bilirubin, and albumin has been demonstrated in the ICM group. The study showed negative correlations between TAC, MDA, and PSH and positive between TAC and MDA in both groups. In ICM patients, MDA positively correlated with UA. A negative correlation between PSH and concentrations of UA and bilirubin was expressed only in the nICM group.

Conclusion

The obtained results confirm the relationship between the severity of HF and oxidative stress. The mechanisms of oxidative stress and antioxidant defence are partially different in the ICM and the nICM patients.

Metabolic Resuscitation Strategies to Prevent Organ Dysfunction in Sepsis

Significance: Sepsis is the main cause of death among patients admitted to the intensive care unit. As current treatment is limited to antimicrobial therapy and supportive care, mortality remains high, which warrants efforts to find novel therapies. Recent Advances: Mitochondrial dysfunction is emerging as a key process in the induction of organ dysfunction during sepsis, and metabolic resuscitation might reveal to be a novel cornerstone in the treatment of sepsis. Critical Issues: Here, we review novel strategies to maintain organ function in sepsis by precluding mitochondrial dysfunction by lowering energetic demand to allow preservation of adenosine triphosphate-levels, while reducing free radical generation. As the most common strategy to suppress metabolism, that is, cooling, does not reveal unequivocal beneficial effects and may even increase mortality, caloric restriction or modulation of energy-sensing pathways (i.e., sirtuins and AMP-activated protein kinase) may offer safe alternatives. Similar effects may be offered when mimicking hibernation by hydrogen sulfide (H₂S). In addition H₂S may also confer beneficial effects through upregulation of antioxidant mechanisms, similar to the other gasotransmitters nitric oxide and carbon monoxide, which display antioxidant and anti-inflammatory effects in sepsis. In addition, oxidative stress may be averted by systemic or mitochondria-targeted antioxidants, of which a wide range are able to lower inflammation, as well as reduce organ dysfunction and mortality from sepsis. Future Directions: Mitochondrial dysfunction plays a key role in the pathophysiology of sepsis. As a consequence, metabolic resuscitation might reveal to be a novel cornerstone in the treatment of sepsis.

Approach of minimal invasive monitoring and initial treatment of the septic patient in emergency medicine

Sepsis and septic shock constitute a complex disease condition that requires the engagement of several medical specialties. A great number of patients with this disease are constantly admitted to the emergency department, which warrants the need for emergency physicians to lead in the recognition and early management of septic patients. Timely and appropriate interventions may help reduce mortality in a disease with an unacceptably high mortality rate. Poor control of cellular hypoperfusion is one of the most influential mechanisms contributing to the high mortality rate in these patients. This article aims to make an evidence-based approach and an algorithm for the active identification of hypoperfusion in patients with suspicion of severe infection, based on both clinical variables (capillary refill, mottling index, left ventricular function by ultrasound, temperature gradient, etc.) and laboratory-measured variables (lactate, central venous oxygen saturation [ScvO₂], and venous-to-arterial carbon dioxide tension difference [P (v-a) CO₂]). Such variables are feasible to use in the emergency department and would help to explain the cause behind the inadequate oxygen use by cells, thereby guiding treatment at the macrovascular, microvascular, or cellular level.

Location-dependent effects of trauma on oxidative stress in humans

Though circulating antioxidant capacity in plasma is homeostatically regulated, it is not known whether acute stressors (i.e. trauma) affecting different anatomical locations could have quantitatively different impacts. For this reason, we evaluated the relationship between the anatomical location of trauma and plasma total antioxidant capacity (TAC) in a prospective study, where the anatomical locations of trauma in polytraumatic patients (n = 66) were categorized as primary affecting the brain -traumatic brain injury (TBI)-, thorax, abdomen and pelvis or extremities. We measured the following: plasma TAC by 2 independent methods, the contribution of selected antioxidant molecules (uric acid, bilirubin and albumin) to these values and changes after 1 week of progression. Surprisingly, TBI lowered TAC (919 ± 335 μM Trolox equivalents (TE)) in comparison with other groups (thoracic trauma 1187 ± 270 μM TE; extremities 1025 ± 276 μM TE; p = 0.004). The latter 2 presented higher hypoxia (PaO₂/FiO₂ 272 ± 87 mmHg) and hemodynamic instability (inotrope use required in 54.5%) as well. Temporal changes in TAC are also dependent on anatomical location, as thoracic and extremity trauma patients’ TAC values decreased (1187 ± 270 to 1045 ± 263 μM TE; 1025 ± 276 to 918 ± 331 μM TE) after 1 week (p < 0.01), while in TBI these values increased (919 ± 335 to 961 ± 465 μM TE). Our results show that the response of plasma antioxidant capacity in trauma patients is strongly dependent on time after trauma and location, with TBI failing to induce such a response.

Plasma Antioxidant Potential at Admission is Associated with Length of ICU Stay in Child with Sepsis: A Pilot Study

OBJECTIVE

To assess the relationship between biomarkers of oxidative stress (OS) and the length of stay in intensive care units (LSICU) in septic children.

METHODS

Clinical parameters and biomarkers of OS were measured in 16 children admitted for sepsis in an intensive care unit. The associations between biomarkers of OS and the LSICU were assessed by linear correlation. Multiple linear regression models were constructed to adjust other variables.

RESULTS

The mean of LSICU was 7.13 ± 4.17 days. LSICU was associated with the catalase activity (rho =0.56, p-value =0.024) and the ferric reducing ability of plasma (FRAP, r = 0.73, p-value =0.001). However, only FRAP at ICU admission was independently associated with LSICU, which rose 0.21 days for each 10 µmol/l of increase in the FRAP level.

CONCLUSION

We conclude for first time that FRAP level at ICU admission is independently associated with LSICU in pediatric patients.

Increased oxidative stress and renal injury in patients with sepsis

Sepsis remains one of the leading causes of death in intensive care units. The early phase of sepsis is characterized by a massive formation of reactive oxygen and nitrogen species such as superoxide and nitric oxide. However, few comprehensive studies on plasma antioxidants have been reported. Increased oxidative stress was confirmed in sepsis patients (n = 18) at the time of hospitalization by a significant decrease in plasma ascorbic acid and a significant increase in the percentage of oxidized form of coenzyme Q10 in total coenzyme Q10 compared to age-matched healthy controls (n = 62). Tissue oxidative damage in patients was suggested by a significant decrease in polyunsaturated fatty acid contents and a significant increase in oleic acid contents in total free fatty acids. Thus, it is reasonable that plasma uric acid (end product of purines) would be significantly elevated. However, uric acid levels were continuously decreased during hospitalization for 7 days, indicating a continuous formation of peroxynitrite. A greater decrease in free cholesterol (FC) compared to cholesterol esters (CE) was observed. Thus, the FC/CE ratio significantly increased, suggesting deficiency of lecithin-cholesterol acyltransferase secreted from the liver. Plasma levels of prosaposin, a coenzyme Q10 binding protein, significantly decreased as compared to healthy controls. This may be correlated with renal injury in sepsis patients, since the kidney is thought to be a major secretor of prosaposin.

Serum total antioxidant capacity during the first week of sepsis and mortality

PURPOSE

Higher circulating total antioxidant capacity (TAC) concentrations have been found in non-survivor than in survivor septic patients at moment of sepsis diagnosis. The objectives of this study were to determine whether serum TAC levels during the first week of sepsis are associated with lipid peroxidation, sepsis severity, and sepsis mortality, and whether could be used as a prognostic biomarker.

METHODS

This prospective and observational study with 319 septic patients admitted to Intensive Care Units was carried out in 8 Spanish hospitals. We determined serum concentrations of malondialdehyde (to estimate lipid peroxidation) and TAC at days 1, 4 and 8 of sepsis. Mortality at 30 days was the end-point study.

RESULTS

We found that serum TAC concentrations at days 1, 4 and 8 could predict 30-day mortality according to ROC curve analyses (p < 0.001), that were associated with 30-day mortality according to regression analyses (p < 0.001), and that were associated with serum levels of malondialdehyde and SOFA score.

CONCLUSIONS

The new findings of our study were that serum TAC levels during the first week of sepsis are associated with lipid peroxidation, sepsis severity, and sepsis mortality, and that could be used as a prognostic biomarker.

Uric acid disrupts hypochlorous acid production and the bactericidal activity of HL-60 cells

Uric acid is the end product of purine metabolism in humans and is an alternative physiological substrate for myeloperoxidase. Oxidation of uric acid by this enzyme generates uric acid free radical and urate hydroperoxide, a strong oxidant and potentially bactericide agent. In this study, we investigated whether the oxidation of uric acid and production of urate hydroperoxide would affect the killing activity of HL-60 cells differentiated into neutrophil-like cells (dHL-60) against a highly virulent strain (PA14) of the opportunistic pathogen Pseudomonas aeruginosa. While bacterial cell counts decrease due to dHL-60 killing, incubation with uric acid inhibits this activity, also decreasing the release of the inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF- α). In a myeloperoxidase/Cl^-/H₂O₂ cell-free system, uric acid inhibited the production of HOCl and bacterial killing. Fluorescence microscopy showed that uric acid also decreased the levels of HOCl produced by dHL-60 cells, while significantly increased superoxide production. Uric acid did not alter the overall oxidative status of dHL-60 cells as measured by the ratio of reduced (GSH) and oxidized (GSSG) glutathione. Our data show that uric acid impairs the killing activity of dHL-60 cells likely by competing with chloride by myeloperoxidase catalysis, decreasing HOCl production. Despite diminishing HOCl, uric acid probably stimulates the formation of other oxidants, maintaining the overall oxidative status of the cells. Altogether, our results demonstrated that HOCl is, indeed, the main relevant oxidant against bacteria and deviation of myeloperoxidase activity to produce other oxidants hampers dHL-60 killing activity.

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Uric acid decreased microbicide activity and release of cytokines by dHL-60 cells.

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Uric acid decreased HOCl in cells and in the myeloperoxidase/Cl^-/H₂O₂ system.

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Uric acid induces a pro-oxidant redox imbalance.

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HOCl is crucial for Pseudomonas aeruginosa killing by dHL-60.

A novel luminol-based enhanced chemiluminescence antioxidant capacity microplate assay for use in different biological matrices

INTRODUCTION

Reactive oxygen species (ROS) are normal metabolic products of living cells. However, a decrease of the defense mechanisms against the effects of ROS or increased ROS production maybe one important causative factor of cellular damage. A non-enzymatic scavenger system is considered to be responsible for the maintenance of total antioxidant capacity (TAC) as a protection against oxidative injuries that exist in all higher plants and in mammals as well.

METHODS

In our work, we optimized and validated a luminol-peroxidase-4-iodophenol-H₂O₂ enhanced chemiluminescence-based (ECL) TAC measurement technique. BSA was applied in the reagent to prevent peroxidase from auto-oxidation. The ECL method was suitable for plant extracts and for human blood serum as well. Our TAC technique was adapted to microplates and compared to ORAC assay using plant extracts.

RESULTS AND DISCUSSION

The ECL method is fast (10min) with an interassay precision of <10% as CV. TAC values of ethanolic extracts of 10 plant species did correlate (ECL vs ORAC assay data: r=0.84, 95% confidence interval, CI=0.78-0.89, P<0.001) but with systematic bias. Analysis of serum samples obtained from septic and control patients showed significantly higher TAC values in the patient group compared to those of controls (p<0.01). Moreover, we could discriminate between surviving and non-surviving patients, based on their TAC values (p<0.01). Pearson's statistics showed the strongest positive correlation with serum uric acid (r=0.73). Besides the routine laboratory parameters, our novel TAC method might give complementary information on the severity of systemic inflammation.

Role of Oxidative Stress and Mitochondrial Dysfunction in Sepsis and Potential Therapies

Sepsis is one of the most important causes of death in intensive care units. Despite the fact that sepsis pathogenesis remains obscure, there is increasing evidence that oxidants and antioxidants play a key role. The imbalance of the abovementioned substances in favor of oxidants is called oxidative stress, and it contributes to sepsis process. The most important consequences are vascular permeability impairment, decreased cardiac performance, and mitochondrial malfunction leading to impaired respiration. Nitric oxide is perhaps the most important and well-studied oxidant. Selenium, vitamin C, and 3N-acetylcysteine among others are potential therapies for the restoration of redox balance in sepsis. Results from recent studies are promising, but there is a need for more human studies in a clinical setting for safety and efficiency evaluation.

Metabolome alterations in severe critical illness and vitamin D status

BACKGROUND

Metabolic homeostasis is substantially disrupted in critical illness. Given the pleiotropic effects of vitamin D, we hypothesized that metabolic profiles differ between critically ill patients relative to their vitamin D status.

METHODS

We performed a metabolomics study on biorepository samples collected from a single academic medical center on 65 adults with systemic inflammatory response syndrome or sepsis treated in a 20-bed medical ICU between 2008 and 2010. To identify key metabolites and metabolic pathways related to vitamin D status in critical illness, we first generated metabolomic data using gas and liquid chromatography mass spectroscopy. We followed this by partial least squares-discriminant analysis to identify individual metabolites that were significant. We then interrogated the entire metabolomics profile using metabolite set enrichment analysis to identify groups of metabolites and pathways that were differentiates of vitamin D status. Finally we performed logistic regression to construct a network model of chemical-protein target interactions important in vitamin D status.

RESULTS

Metabolomic profiles significantly differed in critically ill patients with 25(OH)D ≤ 15 ng/ml relative to those with levels >15 ng/ml. In particular, increased 1,5-anhydroglucitol, tryptophan betaine, and 3-hydroxyoctanoate as well as decreased 2-arachidonoyl-glycerophosphocholine and N-6-trimethyllysine were strong predictors of 25(OH)D >15 ng/ml. The combination of these five metabolites led to an area under the curve for discrimination for 25(OH)D > 15 ng/ml of 0.82 (95% CI 0.71-0.93). The metabolite pathways related to glutathione metabolism and glutamate metabolism are significantly enriched with regard to vitamin D status.

CONCLUSION

Vitamin D status is associated with differential metabolic profiles during critical illness. Glutathione and glutamate pathway metabolism, which play principal roles in redox regulation and immunomodulation, respectively, were significantly altered with vitamin D status.

Parasitological and biochemical studies on cutaneous leishmaniasis in Shara'b District, Taiz, Yemen

BACKGROUND

The leishmaniasis is a group of diseases caused by intracellular haemoflagellate protozoan parasites of the genus Leishmania. Leishmaniasis has diverse clinical manifestations; cutaneous leishmaniasis (CL) is the most common form of leishmaniasis which is responsible for 60% of disability-adjusted life years. CL is endemic in Yemen. In Shara'b there is no reference study available to identify the prevalence of endemic diseases and no investigation has been conducted for diagnosing the diseases.

METHODS

This study was conducted in villages for CL which collected randomly. The study aimed at investigating the epidemiological factors of CL in Shara'b by using questioner. Symptoms of lesions in patients suffering from CL, confirmed by laboratory tests, gave a new evidence of biochemical diagnosis in 525 villagers aged between 1 and 60 years old. Venous bloods were collected from 99 patients as well as from 51 control after an overnight fast.

RESULTS

The percentage prevalence of CL was found 18.8%. The prevalence rate of infection among males (19.3%) was higher than females (18.40%). Younger age group (1-15) had a higher prevalence rate (20.3%) than the other age groups. Furthermore, the population with no formal education had the higher rate of infection (61% of the total). A significant increase of serum malondialdehyde (P < 0.001) in CL patients was obtained. The highest level of MDA may be due to over production of ROS and RNS results in oxidative stress and the acceleration of lipid peroxidation in CL patients.

CONCLUSIONS

There were high prevalence rates of CL in Shara'b. The patient who had CL has been found with many changes in some biochemical levels. This study provides a clear indication on the role of MDA as an early biochemical marker of peroxidation damage occurring during CL. Increased uric acid, and catalase activity was provided of free radical.