Development of a Multivariable Prediction Model for Citrate Accumulation in Liver Transplant Patients Undergoing Continuous Renal Replacement Therapy with Regional Citrate Anticoagulation.

INTRODUCTION: Patients with impaired citrate metabolism may experience citrate accumulation (CA), which causes life-threatening metabolic acidosis and hypocalcemia. CA poses a challenge for clinicians when deciding on the use of regional citrate anticoagulation (RCA) for patients with liver dysfunction. This study aimed to develop a prediction model integrating multiple clinical variables to assess the risk of CA in liver transplant patients. METHODS: This single-center prospective cohort study included postoperative liver transplant patients who underwent continuous renal replacement therapy (CRRT) with RCA. The study end point was CA. A prediction model was developed using a generalized linear mixed-effect model based on the Akaike information criterion. The predictive values were assessed using the receiver operating characteristic curve and bootstrap resampling (times = 500) to estimate the area under the curve (AUC) and the corresponding 95% confidence interval (CI). A nomogram was used to visualize the model. RESULTS: This study included 32 patients who underwent 133 CRRT sessions with RCA. CA occurred in 46 CRRT sessions. The model included lactate, norepinephrine >0.1 µg/kg/min, alanine aminotransferase, total bilirubin, and standard bicarbonate, which were tested before starting each CRRT session and body mass index, diabetes mellitus, and chronic kidney disease as predictors. The AUC of the model was 0.867 (95% CI 0.786-0.921), which was significantly higher than that of the single predictor (p < 0.05). A nomogram visualized the prediction model. CONCLUSIONS: The prediction model integrating multiple clinical variables showed a good predictive value for CA. A nomogram visualized the model for easy application in clinical practice.

Antagonism of Cerebral High Mobility Group Box 1 Ameliorates Dendritic Cell Dysfunction in Sepsis.

Sepsis has emerged as a global health issue, and accounts for millions of deaths in intensive care units. Dysregulation of the immune response reportedly contributes to the pathogenesis and progression of this lethal condition, which involves both the dysfunction of immune cells and incompetent immunomodulatory mechanisms. High mobility group box 1 (HMGB1) is known as a later inflammatory mediator and is critically involved in the severity and prognosis of sepsis by inducing intractable inflammation and dysfunction of various immune cells. In the present study, we found that intracerebroventricular (ICV) injection of Box A, a specific antagonist of HMGB1, restored the dysregulated response of splenic dendritic cells (DCs) in septic mice by enhancing the expression of surface molecules, including CD80, CD86, and MHC-II, as well as improving DC priming of T lymphocytes. Cerebral HMGB1 was also confirmed to have potent inhibitory effects on DC functions when administrated by ICV injection in normal mice. The brain cholinergic system was found to mediate the immunomodulatory effects of central HMGB1, as it exhibited enhanced activity with persistent HMGB1 exposure. Furthermore, the inhibitory effects of cerebral HMGB1 on the response of peripheral DCs were also blocked by α7nAchR gene knockout. These findings provide novel insight into the relationship between cerebral HMGB1 and splenic DC dysfunction during sepsis, which is, at least in part, dependent on cholinergic system activity.

Role of the Ca2+-Calcineurin-Nuclear Factor of Activated T cell Pathway in Mitofusin-2-Mediated Immune Function of Jurkat Cells.

BACKGROUND: Mitofusin-2 (MFN2), a well-known mitochondrial fusion protein, has been shown to participate in innate immunity, but its role in mediating adaptive immunity remains poorly characterized. In this study, we explored the potential role of MFN2 in mediating the immune function of T lymphocytes. METHODS: We manipulated MFN2 gene expression in Jurkat cells via lentiviral transduction of MFN2 small interfering RNA (siRNA) or full-length MFN2. After transduction, the immune response and its underlying mechanism were determined in Jurkat cells. One-way analysis of variance and Student's t-test were performed to determine the statistical significance between the groups. RESULTS: Overexpression of MFN2 enhanced the immune response of T lymphocytes by upregulating Ca2+ (359.280 ± 10.130 vs. 266.940 ± 10.170, P = 0.000), calcineurin (0.513 ± 0.014 vs. 0.403 ± 0.020 nmol/L, P = 0.024), and nuclear factor of activated T cells (NFATs) activation (1.040 ± 0.086 vs. 0.700 ± 0.115, P = 0.005), whereas depletion of MFN2 impaired the immune function of T lymphocytes by downregulating Ca2+ (141.140 ± 14.670 vs. 267.060 ± 9.230, P = 0.000), calcineurin (0.054 ± 0.030 nmol/L vs. 0.404 ± 0.063 nmol/L, P = 0.000), and NFAT activation (0.500 ± 0.025 vs. 0.720 ± 0.061, P = 0.012). Furthermore, upregulated calcineurin partially reversed the negative effects of MFN2 siRNA on T cell-mediated immunity evidenced by elevations in T cell proliferation (1.120 ± 0.048 vs. 0.580 ± 0.078, P = 0.040), interleukin-2 (IL-2) production (473.300 ± 24.100 vs. 175.330 ± 12.900 pg/ml, P = 0.000), and the interferon-γ/IL-4 ratio (3.080 ± 0.156 vs. 0.953 ± 0.093, P = 0.000). Meanwhile, calcineurin activity inhibitor depleted the positive effects of overexpressed MFN2 on T cells function. CONCLUSIONS: Our findings suggest that MFN2 may regulate T cell immune functions primarily through the Ca2+-calcineurin-NFAT pathway. MFN2 may represent a potential therapeutic target for T cell immune dysfunction-related diseases.

The Protective Effect of Alpha 7 Nicotinic Acetylcholine Receptor Activation on Critical Illness and Its Mechanism.

Critical illnesses and injuries are recognized as major threats to human health, and they are usually accompanied by uncontrolled inflammation and dysfunction of immune response. The alpha 7 nicotinic acetylcholine receptor (α7nAchR), which is a primary receptor of cholinergic anti-inflammatory pathway (CAP), exhibits great benefits for critical ill conditions. It is composed of 5 identical α7 subunits that form a central pore with high permeability for calcium. This putative structure is closely associated with its functional states. Activated α7nAChR exhibits extensive anti-inflammatory and immune modulatory reactions, including lowered pro-inflammatory cytokines levels, decreased expressions of chemokines as well as adhesion molecules, and altered differentiation and activation of immune cells, which are important in maintaining immune homeostasis. Well understanding of the effects and mechanisms of α7nAChR will be of great value in exploring effective targets for treating critical diseases.

Early antagonism of cerebral high mobility group box-1 protein is benefit for sepsis induced brain injury.

Sepsis induced brain injury acts as an acute complication and accounts for deterioration and high mortality rate of septic condition. HMGB1 is a late inflammatory mediator that plays a critical role in brain dysfunction and diseases. However, the role of HMGB1 in sepsis induced brain dysfunction remains intricate. The current study investigated the effect of HMGB1 on brain injury in septic mice model with intracerebroventricular injection of BoxA (a specific antagonist of HMGB1). The expression of HMGB1, morphological changes of brain tissues, apoptosis of brain cells, and alteration of behavior were determined. The expressions of HMGB1 in cortex, hippocampus, and striatum were significantly enhanced in the sepsis group when compared with the sham group. In septic conditions, brain tissues showed significant abnormalities in tissue structure, and increased apoptosis of brain cells which was caspase-3 dependent. Septic mice showed suppression of locomotor activity and impairment of memory and learning. Neutralizing brain HMGB1 significantly improved brain injury and apoptosis of brain cells, and further ameliorated disturbed locomotor activities and damaged memory and learning. However, no significant improvement of survival rate was seen after inhibiting central HMGB1. These results reveal that HMGB1 is a potential target for ameliorating sepsis induced brain injury with early antagonizing.

Burn injury induces gelsolin expression and cleavage in the brain of mice.

Gelsolin is an actin filament-severing and capping protein, affecting cellular motility, adhesiveness and apoptosis. Whether it is expressed in the brain of burned mice has not yet been characterized. Mice were subjected to a 15% total body surface area scald injury. Neuropathology was examined by hematoxylin and eosin staining. Cerebral gelsolin mRNA, distribution and cleavage were demonstrated by quantitative polymerase chain reaction (QPCR), immunohistochemistry and Western blot, respectively. Cysteinyl aspartate-specific protease (caspase)-3-positive cells and activity were also measured. Burn injury could induce pathological alterations in the brain including leukocyte infiltration, necrosis, microabscess and gliosis. Compared with sham-injured mice, gelsolin mRNA was up-regulated at 8h post-burn (pb) in a transient manner in the cortex and striatum of burned mice, while it remained at higher levels in the hippocampus up to 72 hpb. Of interest, gelsolin was further cleaved into 42 and 48 kDa (kilo Dalton) fragments as illustrated in the hippocampus at 24 hpb, and was widely expressed in the brain by activated monocyte/macrophages, astrocytes and damaged neurons. In the meantime, caspase-3-positive cells were noted in the striatum of burned mice and its activity peaked at 24 hpb. To clarify inflammation-induced gelsolin expression and cleavage in the brain, rat pheochromocytoma cells were exposed to lipopolysaccharide to show increased gelsolin expression and caspase-3-dependent cleavage. The results suggest that burn-induced cerebral gelsolin expression would be involved in the activation of both the monocytes and astroglial cells, thereby playing a crucial role in the subsequent inflammation-induced neural apoptosis following burn injury.