IL-6 protects cardiomyocytes from oxidative stress at the early stage of LPS-induced sepsis

Advanced progress of adipose-derived stem cells-related biomaterials in maxillofacial regeneration

The tissue injury in maxillofacial region affects patients' physical function and specific mental health. This decade, utilizing regenerative medicine to achieve tissue regeneration has been proved a hopeful direction. Seed cells play a vital role in regeneration strategy. Among various kinds of stem cells that effectively to regenerate the soft and hard tissue of maxillofacial region, adipose-derived stem cells (ADSCs) have gained increasing interests of researchers due to their abundant sources, easy availability and multi-differentiation potentials in recent decades. Thus, this review focuses on the advances of ADSCs-based biomaterial in maxillofacial regeneration from the progress and strategies perspective. It is structured as introducing the properties of ADSCs, biomaterials (polymers, ceramics and metals) within ADSCs and the latest applications of ADSCs in maxillofacial regeneration, including temporomandibular joint (TMJ), bone, periodontal tissue, tooth, nerve as well as cosmetic field. In order to further facilitate ADSCs-based therapies as an emerging platform for regenerative medicine, this review also emphasized current challenges in translating ADSC-based therapies into clinical application and dissussed the strategies to solve these obstacles.

Tocilizumab does not ameliorate inflammation-induced left ventricular dysfunction in a collagen-induced arthritis rat model

BACKGROUND

Interleukin-6 (IL-6) is an attractive therapeutic target due to its diverse roles in the pathogenesis of conditions characterized by systemic inflammation. IL-6 has also been implicated in the pathophysiology of heart failure. This study aimed to investigate the impact of IL-6 receptor blockade with tocilizumab on the molecular pathways underlying systemic inflammation-induced left ventricular (LV) dysfunction in a collagen-induced arthritis (CIA) rat model.

METHODS

Seventy-three Sprague-Dawley rats were divided into three groups: control (n=28), CIA (n=29), and CIA+IL-6 blocker (n=16). Inflammation was induced in the CIA and CIA+IL-6 blocker groups using bovine type II collagen emulsified in incomplete Freund's adjuvant. After arthritis onset, the CIA+IL-6 blocker group received tocilizumab for six weeks. Circulating inflammatory markers, relative LV mRNA gene expressions, and LV systolic and diastolic function were assessed.

RESULTS

CIA rats developed LV diastolic and early-stage LV systolic dysfunction, which was not ameliorated by IL-6 blocker administration (p > 0.05). IL-6 blocker administration did not impact circulating inflammatory markers (all p > 0.05) or LV mRNA expression of inflammatory markers compared to the CIA group, nor did it reverse inflammation-induced increases in LV mRNA expression of genes involved in fibrosis and collagen turnover, regulation of titin phosphorylation, Ca2+ handling, mitochondrial function, or apoptosis (all p > 0.05). However, LV mRNA expressions of CD68 and LOX, genes involved in macrophage infiltration and collagen cross-linking, were increased in the CIA group (p = 0.03, p = 0.0004), but not in the CIA+IL-6 blocker group compared to controls (p > 0.05).

CONCLUSION

These results suggest that although IL-6 blockade by tocilizumab may prevent inflammation-induced collagen cross-linking, the current treatment regimen may not protect against inflammation-induced LV dysfunction. Therefore, the role of IL-6 in the molecular mechanisms of inflammation-induced LV dysfunction remains inconclusive.

Glutathione Depletion Exacerbates Hepatic Mycobacterium tuberculosis Infection

Extrapulmonary tuberculosis (EPTB) accounts for approximately 17% of all Mycobacterium tuberculosis (M.tb) infections globally. Immunocompromised individuals, such as those with HIV infection or type 2 diabetes mellitus (T2DM), are at an increased risk for EPTB. Previous studies have demonstrated that patients with HIV and T2DM exhibit diminished synthesis of glutathione (GSH) synthesizing enzymes. In a murine model, we showed that the diethyl maleate (DEM)-induced depletion of GSH in the lungs led to increased M.tb burden and an impaired pulmonary granulomatous response to M.tb infection. However, the effects of GSH depletion during active EPTB in the liver and spleen have yet to be elucidated. In this study, we evaluated hepatic GSH and malondialdehyde (MDA) levels, as well as cytokine profiles, in untreated and DEM-treated M.tb-infected wild-type (WT) C57BL/6 mice. Additionally, we assessed hepatic and splenic M.tb burdens and tissue pathologies. DEM treatment resulted in a significant decrease in the levels of the reduced form of GSH and an increase in MDA, oxidized GSH, and interleukin (IL)-6 levels. Furthermore, DEM-induced GSH decrease was associated with decreased production of IL-12 and IL-17 and elevated production of interferon-gamma (IFN-γ), tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β. A significant increase in M.tb growth was detected in the liver and spleen in DEM-treated M.tb-infected mice. Large, disorganized lymphocyte infiltrates were detected in the hepatic tissues of DEM-treated mice. Overall, GSH diminishment impaired the granulomatous response to M.tb in the liver and exacerbated M.tb growth in both the liver and spleen. These findings provide critical insights into the immunomodulatory role of GSH in TB pathogenesis and suggest potential therapeutic avenues for the treatment of extrapulmonary M.tb infections.

A murine model of acute and prolonged abdominal sepsis, supported by intensive care, reveals time-dependent metabolic alterations in the heart

BACKGROUND

Sepsis-induced cardiomyopathy (SICM) often occurs in the acute phase of sepsis and is associated with increased mortality due to cardiac dysfunction. The pathogenesis remains poorly understood, and no specific treatments are available. Although SICM is considered reversible, emerging evidence suggests potential long-term sequelae. We hypothesized that metabolic and inflammatory cardiac changes, previously observed in acute sepsis as potential drivers of SICM, partially persist in prolonged sepsis.

METHODS

In 24-week-old C57BL/6J mice, sepsis was induced by cecal ligation and puncture, followed by intravenous fluid resuscitation, subcutaneous analgesics and antibiotics, and, in the prolonged phase, by parenteral nutrition. Mice were killed after 5 days of sepsis (prolonged sepsis, n = 15). For comparison, we included acutely septic mice killed at 30 h (acute sepsis, n = 15) and healthy controls animals (HC, n = 15). Cardiac tissue was collected for assessment of inflammatory and metabolic markers through gene expression, metabolomic analysis and histological assessment.

RESULTS

In prolonged sepsis, cardiac expression of IL-1β and IL-6 and macrophage infiltration remained upregulated (p ≤ 0.05). In contrast, tissue levels of Krebs cycle intermediates and adenosine phosphates were normal, whereas NADPH levels were low in prolonged sepsis (p ≤ 0.05). Gene expression of fatty acid transporters and of the glucose transporter Slc2a1 was upregulated in prolonged sepsis (p ≤ 0.01). Lipid staining and glycogen content were elevated in prolonged sepsis together with increased gene expression of enzymes responsible for lipogenesis and glycogen synthesis (p ≤ 0.05). Intermediate glycolytic metabolites (hexose-phosphates, GADP, DHAP) were elevated (p ≤ 0.05), but gene expression of several enzymes for glycolysis and mitochondrial oxidation of pyruvate, fatty-acyl-CoA and ketone bodies to acetyl-CoA were suppressed in prolonged sepsis (p ≤ 0.05). Key metabolic transcription factors PPARα and PGC-1α were downregulated in acute, but upregulated in prolonged, sepsis (p ≤ 0.05 for both). Ketone body concentrations were normal but ketolytic enzymes remained suppressed (p ≤ 0.05). Amino acid metabolism showed mild, mixed changes.

CONCLUSIONS

Our results suggest myocardial lipid and glycogen accumulation and suppressed mitochondrial oxidation, with a functionally intact Krebs cycle, in the prolonged phase of sepsis, together with ongoing myocardial inflammation. Whether these alterations have functional consequences and predispose to long-term sequelae of SICM needs further research.

Evaluation of Sepsis Severity Using Combined High-Density Lipoprotein and Red Cell Distribution Width Indicators

Aims/Background Sepsis is a life-threatening condition resulting from dysregulated immune responses to infection, leading to organ dysfunction. High-density lipoprotein (HDL) and red cell distribution width (RDW) have shown significant correlations with sepsis severity, yet the combined prognostic value of HDL and RDW in evaluating sepsis severity and outcomes remains unclear. This study examines the relationship between HDL and RDW levels and sepsis severity, as well as evaluates the combined utility of these markers in predicting disease severity and patient outcomes. Methods This retrospective study included 103 patients diagnosed with sepsis. Clinical data, including HDL and RDW levels, were collected for analysis. Patients were divided into shock and non-shock groups based on the presence of septic shock and into survival and death groups based on 30-day in-hospital mortality. Multivariate logistic regression was used to identify factors influencing sepsis severity and prognosis, while the predictive value of HDL in combination with RDW was evaluated using receiver operating characteristic (ROC) curve analysis. Results Multivariate analysis identified sequential organ failure assessment (SOFA) score (OR = 6.566), interleukin-6 (IL-6) (OR = 2.568), HDL (OR = 0.864), and RDW (OR = 4.052) as independent predictors of sepsis severity (p < 0.05 for all). ROC analysis demonstrated that HDL combined with RDW yielded the highest diagnostic accuracy for sepsis severity, with an area under curve (AUC) of 0.962, sensitivity of 97.56%, and specificity of 91.94%. Additionally, SOFA score (OR = 2.354), interleukin-6 (IL-6) (OR = 1.446), HDL (OR = 0.870), and RDW (OR = 3.502) were independent prognostic indicators (p < 0.05 for all). ROC analysis for prognosis showed that HDL combined with RDW had the highest predictive efficacy for the prognosis of sepsis, with an AUC of 0.922, sensitivity of 79.31%, and specificity of 93.24%. Conclusion The combination of HDL and RDW is a robust indicator for the evaluation of sepsis severity and is a valuable prognostic tool for assessing 30-day mortality risk in sepsis patients.

Myokines: metabolic regulation in obesity and type 2 diabetes

Skeletal muscle plays a vital role in the regulation of systemic metabolism, partly through its secretion of endocrine factors which are collectively known as myokines. Altered myokine levels are associated with metabolic diseases, such as type 2 diabetes (T2D). The significance of interorgan crosstalk, particularly through myokines, has emerged as a fundamental aspect of nutrient and energy homeostasis. However, a comprehensive understanding of myokine biology in the setting of obesity and T2D remains a major challenge. In this review, we discuss the regulation and biological functions of key myokines that have been extensively studied during the past two decades, namely interleukin 6 (IL-6), irisin, myostatin (MSTN), growth differentiation factor 11 (GDF11), fibroblast growth factor 21 (FGF21), apelin, brain-derived neurotrophic factor (BDNF), meteorin-like (Metrnl), secreted protein acidic and rich in cysteine (SPARC), β-aminoisobutyric acid (BAIBA), Musclin, and Dickkopf 3 (Dkk3). Related to these, we detail the role of exercise in myokine expression and secretion together with their contributions to metabolic physiology and disease. Despite significant advancements in myokine research, many myokines remain challenging to measure accurately and investigate thoroughly. Hence, new research techniques and detection methods should be developed and rigorously tested. Therefore, developing a comprehensive perspective on myokine biology is crucial, as this will likely offer new insights into the pathophysiological mechanisms underlying obesity and T2D and may reveal novel targets for therapeutic interventions.

Nonlinear Relationship Between Interleukin-6 and NT-proBNP at Admission in Hospitalized COVID-19 Patients

Purpose

Elevated levels of the inflammatory marker interleukin-6 (IL-6) and cardiac injury marker N-terminal pro-B-type natriuretic peptide (NT-proBNP) have been observed in patients with coronavirus disease 2019 (COVID-19). However, the relationship between IL-6 and NT-proBNP levels remains unclear. Therefore, we investigated the relationship between IL-6 and NT-proBNP levels in patients with COVID-19.

Patients and Methods

This was a cross-sectional study. Consecutive patients with COVID-19 were included herein. The independent and dependent target variables were the IL-6 and NT-proBNP levels, respectively, measured at baseline. Univariate and multivariate linear regression analyses and curve fitting were also performed.

Results

The average age of the 121 selected participants was 49.8 ± 15.8 years old, and 48.8% (59/121) were male. The estimated β value between Ln-transformed IL-6 and NT-proBNP was 0.28 (95% confidence interval [CI] 0.12-0.44, P = 0.001) in univariate logistic regression analysis and 0.09 (95% CI -0.04-0.21, P = 0.176) in the fully adjusted model. This relationship was nonlinear, with a point of 2.7, and the β values (and CIs) for the left (<2.7) and right (≥2.7) sides of the inflection point were -0.06 (95% CI -0.23-0.12, P = 0.534) and 0.77 (95% CI 0.18-1.37, P = 0.016) in the fully adjusted model, respectively.

Conclusion

Our results suggest a nonlinear association between IL-6 and NT-proBNP levels. Higher IL-6 levels are associated with NT-proBNP in patients with COVID-19.

Exerkines and redox homeostasis

Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the finding of several circulating factors that mediate the effects of exercise. These factors, termed exerkines, are metabolites, growth factors, and cytokines secreted by main metabolic organs during exercise to regulate exercise systemic and tissue-specific effects. The metabolic effects of exerkines have been broadly explored and entail a promising target to modulate beneficial effects of exercise in health and disease. However, exerkines also have broad effects to modulate redox signaling and homeostasis in several cellular processes to improve stress response. Since redox biology is central to exercise physiology, this review summarizes current evidence for the cross-talk between redox biology and exerkines actions. The role of exerkines in redox biology entails a response to oxidative stress-induced pathological cues to improve health outcomes and to modulate exercise adaptations that integrate redox signaling.

Oxidative Stress Response Kinetics after 60 Minutes at Different Levels (10% or 15%) of Normobaric Hypoxia Exposure

In this study, the metabolic responses of hypoxic breathing for 1 h to inspired fractions of 10% and 15% oxygen were investigated. To this end, 14 healthy nonsmoking subjects (6 females and 8 males, age: 32.2 ± 13.3 years old (mean ± SD), height: 169.1 ± 9.9 cm, and weight: 61.6 ± 16.2 kg) volunteered for the study. Blood samples were taken before, and at 30 min, 2 h, 8 h, 24 h, and 48 h after a 1 h hypoxic exposure. The level of oxidative stress was evaluated by considering reactive oxygen species (ROS), nitric oxide metabolites (NOx), lipid peroxidation, and immune-inflammation by interleukin-6 (IL-6) and neopterin, while antioxidant systems were observed in terms of the total antioxidant capacity (TAC) and urates. Hypoxia abruptly and rapidly increased ROS, while TAC showed a U-shape pattern, with a nadir between 30 min and 2 h. The regulation of ROS and NOx could be explained by the antioxidant action of uric acid and creatinine. The kinetics of ROS allowed for the stimulation of the immune system translated by an increase in neopterin, IL-6, and NOx. This study provides insights into the mechanisms through which acute hypoxia affects various bodily functions and how the body sets up the protective mechanisms to maintain redox homeostasis in response to oxidative stress.

Inflammatory mechanisms and intervention strategies for sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) is the leading cause of death in patients with sepsis in the intensive care units. The main manifestations of SIMD are systolic and diastolic dysfunctions of the myocardium. Despite our initial understanding of the SIMD over the past three decades, the incidence and mortality of SIMD remain high. This may be attributed to the large degree of heterogeneity among the initiating factors, disease processes, and host states involved in SIMD. Previously, organ dysfunction caused by sepsis was thought to be an impairment brought about by an excessive inflammatory response. However, many recent studies have shown that SIMD is a consequence of a combination of factors shaped by the inflammatory responses between the pathogen and the host. In this article, we review the mechanisms of the inflammatory responses and potential novel therapeutic strategies in SIMD.

Prehabilitation Ameliorates Gut Ischemia Reperfusion Injury in Mice

INTRODUCTION

We previously demonstrated that prehabilitation by running on a treadmill leads to improved survival after gut ischemia reperfusion (I/R) in mice. The purpose of this research was to examine whether prehabilitation attenuates inflammatory responses after gut I/R in mice.

MATERIALS AND METHODS

Male C57BL/6J mice (n = 92) were assigned to the sedentary (n = 46) or the exercise (n = 46) group. The exercise group ran on a treadmill for 4 wk, while the sedentary mice did not exercise. After the 4-week pretreatment, all mice underwent gut I/R and the blood, urine, small intestine, lung, liver, and gastrocnemius were harvested prior to ischemia or at 0, 3, 6, or 24 h after reperfusion. Histologically demonstrated organ damage, cytokine levels in the blood, gut and gastrocnemius, myeloperoxidase activity in the gut, 8-hydroxy-2'-deoxyguanosine levels in urine and the gut, and adenosine triphosphate (ATP) and ATP + ADP + adenosine monophosphate levels in the gut and gastrocnemius were evaluated.

RESULTS

The treadmill exercise reduced gut and lung injuries at 3 h and liver injury at 6 h after reperfusion. Running on the treadmill also decreased proinflammatory cytokine levels in the blood at 6 h, gut at 3 h and gastrocnemius at 6 h after reperfusion, myeloperoxidase activity in the gut prior to ischemia, and 6 h after reperfusion and the urinary 8-hydroxy-2'-deoxyguanosine level at 24 h after reperfusion, while ATP levels in exercised mice prior to ischemia and 3 h after reperfusion were increased in the intestine as compared to the levels in sedentary mice.

CONCLUSIONS

Prehabilitation with treadmill exercise reduces inflammatory responses after gut I/R and may exert protective actions against gut I/R.

Pathogenesis of Anemia in Canine Babesiosis: Possible Contribution of Pro-Inflammatory Cytokines and Chemokines-A Review

Canine babesiosis is a tick-borne protozoan disease caused by intraerythrocytic parasites of the genus Babesia. The infection may lead to anemia in infected dogs. However, anemia is not directly caused by the pathogen. The parasite's developmental stages only have a marginal role in contributing to a decreased red blood cell (RBC) count. The main cause of anemia in affected dogs is the immune response to the infection. This response includes antibody production, erythrophagocytosis, oxidative damage of RBCs, complement activation, and antibody-dependent cellular cytotoxicity. Moreover, both infected and uninfected erythrocytes are retained in the spleen and sequestered in micro-vessels. All these actions are driven by pro-inflammatory cytokines and chemokines, especially IFN-γ, TNF-α, IL-6, and IL-8. Additionally, imbalance between the actions of pro- and anti-inflammatory cytokines plays a role in patho-mechanisms leading to anemia in canine babesiosis. This article is a review of the studies on the pathogenesis of anemia in canine babesiosis and related diseases, such as bovine or murine babesiosis and human or murine malaria, and the role of pro-inflammatory cytokines and chemokines in the mechanisms leading to anemia in infected dogs.

The underlying pathological mechanism of ferroptosis in the development of cardiovascular disease

Cardiovascular diseases (CVDs) have been attracting the attention of academic society for decades. Numerous researchers contributed to figuring out the core mechanisms underlying CVDs. Among those, pathological decompensated cellular loss posed by cell death in different kinds, namely necrosis, apoptosis and necroptosis, was widely regarded to accelerate the pathological development of most heart diseases and deteriorate cardiac function. Recently, apart from programmed cell death revealed previously, ferroptosis, a brand-new cellular death identified by its ferrous-iron-dependent manner, has been demonstrated to govern the occurrence and development of different cardiovascular disorders in many types of research as well. Therefore, clarifying the regulatory function of ferroptosis is conducive to finding out strategies for cardio-protection in different conditions and improving the prognosis of CVDs. Here, molecular mechanisms concerned are summarized systematically and categorized to depict the regulatory network of ferroptosis and point out potential therapeutic targets for diverse cardiovascular disorders.