Role of Imaging Modalities and N-Acetylcysteine Treatment in Sepsis-Associated Encephalopathy

CEST MRI in the Management/Diagnosis of Neuroinfectious Diseases

Chemical exchange saturation transfer (CEST) MRI is a novel technique that allows for the specific imaging of certain molecules that contain exchangeable protons. Neuroimaging is a major contributor to diagnosing and monitoring infections of the central nervous system (CNS). This review focuses on summarizing the current literature surrounding the use of CEST MRI imaging in diagnosing, monitoring, and treating CNS infections. BacCEST is a new technique to detect bacterial infection in organs at profound levels. This technique allows for the specific pathogen causing the infection to be understood, allowing for tailored antibiotic therapies. The bacCEST signal is also directly proportional to the number of bacterial cells; this means it can be used over periods to track response to treatment via cell numbers. The results show that most of the research in this area has focused on infections of the brain parenchyma (e.g., encephalitis) and that most studies investigate the use of CEST in animal models, with a minority exploring the application of CEST to human participants. The common neuroinfectious disease presentations relevant to clinical medicine are also briefly described, as well as the traditional and modern imaging techniques used to visualize them.

Diagnostic value of the combined detection of serum tumor necrosis factor-α and fecal calprotectin in early sepsis-related encephalopathy

Objective

To investigate the value of tumor necrosis factor-α (TNF-α) and fecal calprotectin in the early diagnosis and prognosis of sepsis-associated encephalopathy (SAE).

Methods

We recruited 150 patients with sepsis, admitted from January 2020 to January 2022. Of these, 80 patients had SAE and 70 patients did not. The levels of serum TNF-α and fecal calprotectin of patients while in the intensive care unit were measured and correlated with the acute physiology and chronic health evaluation scoring system II (APACHE II) score, the sequential organ failure assessment (SOFA) score and 28-day mortality. We examined the value of TNF-α and fecal calprotectin in the diagnosis and prognosis of SAE.

Results

The APACHE II and SOFA scores and 28-day mortality of the SAE group were significantly higher than those of the sepsis group, which indicated that the condition of the SAE group was more critical. In the SAE group, TNF-α and fecal calprotectin levels were positively correlated with the APACHE II and SOFA scores (P < 0.05), which may be related to disease severity. Assessing TNF-α level alongside fecal calprotectin level is highly valuable for the diagnosis of SAE and determining poor prognoses in SAE patients.

Conclusions

TNF-α and fecal calprotectin may be involved in the pathogenesis of SAE. Both have high specificity and sensitivity for early SAE diagnosis. Moreover, they have good predictive value and can serve as prognostic indicators.

The triglyceride glucose index and delirium risk in sepsis patients: A causal inference study

BACKGROUND

Sepsis, a grave systemic infection, presents substantial health challenges. While insulin resistance frequently occurs in sepsis conditions, its relationship with sepsis-associated delirium remains insufficiently explored.

AIM

This study aimed to explore the causal effect between the triglyceride glucose (TyG) index and its risk of delirium in patients with sepsis through the use of causal inference.

STUDY DESIGN

A cohort of 5461 sepsis patients admitted to the intensive care unit (ICU) was selected from the Medical Information Mart for Intensive Care IV database. Patients were grouped into high TyG (≥9.48) and low TyG (<9.48) categories. Propensity score matching was applied to control for confounders, and the average treatment effect on the treated was calculated.

RESULTS

Of the 5461 patients, 59.6% experienced delirium. The incidence of delirium was higher in the high TyG group (1751 patients; 66.6%) than in the low TyG group (56.3%) (p < .001). The results of the logistic regression analysis indicated that the risk of delirium was significantly higher in the high TyG group (adjusted odds ratio 1.34, 95% confidence interval: 1.16-1.53). Following matching, the delirium risk increased by 6.9% in the high TyG group (T = 3.29), a finding that was confirmed by a Rosenbaum sensitivity analysis.

CONCLUSIONS

The TyG index represents a straightforward and efficacious instrument for nursing staff to ascertain the likelihood of delirium in patients with sepsis during the routine monitoring of their condition. The ability to make causal inferences in observational studies provides a novel approach to research.

RELEVANCE TO CLINICAL PRACTICE

The TyG index represents a readily applicable instrument for ICU nurses to identify the risk of delirium in sepsis patients. This enables the possibility of early intervention in high-risk individuals and the optimization of care outcomes.

The Effect of Disulfiram and N-Acetylcysteine, Potential Compensators for Sulfur Disorders, on Lipopolysaccharide-Induced Neuroinflammation Leading to Memory Impairment and the Metabolism of L-Cysteine Disturbance

BACKGROUND

The role of sulfur-containing drugs, disulfiram (DSF) and N-acetylcysteine (NAC), in alleviating neuroinflammation is poorly understood. The objective of this study was to examine the effect of DSF and NAC on memory and on the metabolism of L-cysteine and inflammation-related parameters in the cerebral cortex of rats in a model of neuroinflammation induced by the administration of lipopolysaccharide (LPS).

METHODS

All the treatments were administered intraperitoneally for 10 days (LPS at a dose of 0.5 mg/kg b.w., DSF at a dose of 100 mg/kg b.w, and NAC at a dose of 100 mg/kg b.w.). Behavior was evaluated by the novel object recognition (NOR) test and object location (OL) test, and the level of brain-derived neurotrophic factor (BDNF) was assayed to evaluate neuronal functioning. Cerebral cortex homogenates were tested for hydrogen sulfide (H2S), sulfane sulfur, sulfates, non-protein sulfhydryl groups (NPSH), nitric oxide (NO), and reactive oxygen species (ROS) by biochemical analysis.

RESULTS

Neither DSF nor NAC alleviated LPS-induced memory disorders estimated by the NOR test and OL test. The studied compounds also did not affect significantly the levels of BDNF, ROS, NO, H2S, and sulfane sulfur in the cerebral cortex. However, we observed an increase in sulfate concentration in brain tissues after LPS treatment, while DSF and NAC caused an additional increase in sulfate concentration. On the other hand, our study showed that the administration of DSF or NAC together with LPS significantly enhanced the cortical level of NPSH, of which glutathione is the main component.

CONCLUSIONS

Our study did not confirm the suggested potential of DSF and NAC to correct memory disorders; however, it corroborated the notion that they reduced oxidative stress induced by LPS by increasing the NPSH level. Additionally, our study showed an increase in sulfate concentration in the brain tissues after LPS treatment, which means the upregulation of sulfite and sulfate production in inflammatory conditions.

Prophylactic Effects of n-Acethylcysteine on Inflammation-induced Depression-like Behaviors in Mice

Depression, affecting individuals worldwide, is a prevalent mental disease, with an increasing incidence. Numerous studies have been conducted on depression, yet its pathogenesis remains elusive. Recent advancements in research indicate that disturbances in synaptic transmission, synaptic plasticity, and reduced neurotrophic factor expression significantly contribute to depression's pathogenesis. In our study, we utilized adult male C57BL/6J mice. Lipopolysaccharide (LPS) can induce both chronic and acute depression-like symptoms in mice, a widely used model for studying depression associated with inflammation. N-acetylcysteine (NAC) exhibits anti-inflammatory and ameliorative effects on depressive symptoms. This study sought to determine whether NAC use could mitigate inflammatory depressive behavior through the enhancement of synaptic transmission, synaptic plasticity, and increasing levels of brain-derived neurotrophic factor (BDNF). In this study, we discovered that in mice modeled with depression-like symptoms, the expression levels of dendrites, BDNF, and miniature excitatory postsynaptic potential (mEPSC) in glutamatergic neurons, as well as the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid glutamate receptors (AMPARs) GluA1 and GluA2 subunits, were significantly decreased. These findings suggest an impairment in the synaptic transmission of glutamatergic neurons. Following treatment with NAC, the previously mentioned levels improved, indicating an enhancement in both synaptic transmission and synaptic plasticity. Our results suggest that NAC exerts a protective effect on mouse models of inflammatory depression, potentially through the enhancement of synaptic transmission and plasticity, as well as the restoration of neurotrophic factor expression. These findings offer vital animal experimental evidence supporting NAC's role in mitigating inflammatory depressive behaviors.

N-Acetylcysteine Attenuates Sepsis-Induced Muscle Atrophy by Downregulating Endoplasmic Reticulum Stress

(1) Background: Sepsis-induced muscle atrophy is characterized by a loss of muscle mass and function which leads to decreased quality of life and worsens the long-term prognosis of patients. N-acetylcysteine (NAC) has powerful antioxidant and anti-inflammatory properties, and it relieves muscle wasting caused by several diseases, whereas its effect on sepsis-induced muscle atrophy has not been reported. The present study investigated the effect of NAC on sepsis-induced muscle atrophy and its possible mechanisms. (2) Methods: The effect of NAC on sepsis-induced muscle atrophy was assessed in vivo and in vitro using cecal ligation and puncture-operated (CLP) C57BL/6 mice and LPS-treated C2C12 myotubes. We used immunofluorescence staining to analyze changes in the cross-sectional area (CSA) of myofibers in mice and the myotube diameter of C2C12. Protein expressions were analyzed by Western blotting. (3) Results: In the septic mice, the atrophic response manifested as a reduction in skeletal muscle weight and myofiber cross-sectional area, which is mediated by muscle-specific ubiquitin ligases-muscle atrophy F-box (MAFbx)/Atrogin-1 and muscle ring finger 1 (MuRF1). NAC alleviated sepsis-induced skeletal muscle wasting and LPS-induced C2C12 myotube atrophy. Meanwhile, NAC inhibited the sepsis-induced activation of the endoplasmic reticulum (ER) stress signaling pathway. Furthermore, using 4-Phenylbutyric acid (4-PBA) to inhibit ER stress in LPS-treated C2C12 myotubes could partly abrogate the anti-muscle-atrophy effect of NAC. Finally, NAC alleviated myotube atrophy induced by the ER stress agonist Thapsigargin (Thap). (4) Conclusions: NAC can attenuate sepsis-induced muscle atrophy, which may be related to downregulating ER stress.