HMGB1 as a key mediator of tissue response to injury: roles in inflammation and tissue repair

Intraoperative Peritoneal Interleukin-6 Concentration Changes in Relation to the High-Mobility Group Protein B1 and Heat Shock Protein 70 Levels in Children Undergoing Cholecystectomy

The aim was the evaluation of IL-6 concentration in peritoneal lavage fluid of children which underwent cholecystectomy to ascertain if there is a difference in early inflammatory response depending on the type of surgical approach (open vs. laparoscopy). The analysis of high-mobility group protein B1 (HMGB1) and heat shock protein 70 (HSP70) was performed to find out if the source of IL-6 was related to tissue damage. IL-6 concentration in peritoneal lavage fluid samples, obtained at the beginning and at the end of the laparoscopic (N = 23) and open cholecystectomy (N = 14), was tested with a routinely used electrochemiluminescence assay. The concentrations of HMGB1 and HSP70 were analyzed with the use of an ELISA method. Statistical analysis was performed using the STATISTICA PL release 12.5 Program. The differences were assessed using the Mann-Whitney U test and Wilcoxon matched pairs test. Correlations were studied by using the Spearman correlation test. Our results demonstrated significant peritoneal lavage fluid IL-6 concentration growth measured at the end of the cholecystectomy as compared to the beginning, regardless of the type of the procedure. IL-6 growth during open cholecystectomy was greater compared to laparoscopic cholecystectomy (62.51-fold vs. 3.19-fold). IL-6 concentration did not correlate with HMGB1 and HSP70, which indicate that the significant growth of this cytokine was not related to mechanical tissue damage due to surgical procedure. A clinical significance of the study could be related to the fact that the evaluation of IL-6 concentration in peritoneal lavage fluid may be useful to assess an early local inflammatory response.

Intravenous, Perioperatively Administered Lidocaine Regulates Serum Pain Modulators’ Concentrations in Children Undergoing Spinal Surgery

Objectives

We analyzed the influence of perioperative, intravenous (i.v.) lidocaine infusion as a part of multimodal anesthesia on concentrations of selected pain modulators.

Design

An observational study.

Setting

University Children’s Hospital in Cracow, Poland, from May 2015 to May 2018.

Subjects

Forty-four children undergoing extensive spinal surgery, divided into two groups after surgery: the study group (N = 23), anesthetized generally with lidocaine as a co-analgesic, and the control group (N = 22), anesthetized generally without lidocaine.

Methods

We assessed proinflammatory mediators like neuron growth factor (NGF), high mobility group box 1 (HMGB1), interleukin 6 (IL-6), and FOS protein before, immediately after, six hours and 12–15 hours after surgery. We evaluated pain intensity at corresponding time points using a 10-point numerical/graphical scale.

Results

We observed that children in the lidocaine group had reduced pain intensity in the resting state and during movement until six hours after surgery when compared with controls. We found lower NGF concentrations in the lidocaine group vs controls only at six hours after surgery. Mean HMGB1 concentrations during the postoperative period in the study group were relatively stable, whereas we observed significant increases at six hours after surgery and a slight decrease at 12–15 hours after surgery in the control group. IL-6 concentrations at six hours were lower in lidocaine patients when compared with controls. We noted a negative correlation between HMGB1, NGF, Il-6, and lidocaine concentrations after surgery. We did not find any differences in FOS protein concentrations between the groups.

Conclusions

Our findings suggest that intraoperative and postoperative i.v. lidocaine administration as a part of multimodal anesthesia may reduce inflammatory-dependent postoperative pain intensity.

Dental Pulp Stem Cell Recruitment Signals within Injured Dental Pulp Tissue

The recruitment of dental pulp stem cells (DPSC) is a prerequisite for the regeneration of dentin damaged by severe caries and/or mechanical injury. Understanding the complex process of DPSC recruitment will benefit future in situ tissue engineering applications based on the stimulation of endogenous DPSC for dentin pulp regeneration. The current known mobilization signals and subsequent migration of DPSC towards the lesion site, which is influenced by the pulp inflammatory state and the application of pulp capping materials, are reviewed. The research outcome of migration studies may be affected by the applied methodology, which should thus be chosen with care. Both the advantages and disadvantages of commonly used assays for investigating DPSC migration are discussed. This review highlights the fact that DPSC recruitment is dependent not only on the soluble chemotactic signals, but also on their interaction with neighboring cells and the extracellular matrix, which can be modified under pathological conditions. These are discussed to explain how these modifications lead to the stimulation of DPSC recruitment.

HMGB-1 as a novel predictor of disease severity and prognosis in patients with hemorrhagic fever with renal syndrome

Objective. To examine the predictive capacity of the high mobility group box protein-1 (HMGB-1) for disease severity and prognosis of hemorrhagic fever with renal syndrome (HFRS). Methods. One hundred and five HFRS patients and 28 controls were studied. The concentrations of HMGB-1 in the blood were measured with a commercially available ELISA. The levels of white blood cells (WBC), platelets (PLT), hematocrit (HCT), albumin (ALB), blood urea nitrogen (BUN), serum creatinine (Scr), and uric acid (UA) were routinely tested in the same time frame. Results. The levels of HMGB-1 increased with the severity of the disease (P < 0.001). HMGB-1 was positively correlated with WBC and BUN and negatively correlated with PLT, ALB, and UA (P < 0.001). HMGB-1 showed statistical significance for predicting prognosis (AUC = 0.800, P < 0.001). The sensitivity and specificity of HMGB-1, WBC, PLT, and ALB used in combination for predicting outcome were better than those of single analyses (AUC = 0.892, P < 0.001). Conclusions. HMGB-1 can be considered a novel biomarker for severity and outcome in patients with HFRS. The use of HMGB-1, WBC, PLT, and ALB in combination to predict the outcome in patients with HFRS exhibited an acceptable level of diagnostic capability.

Expression of high mobility group box 1 in inflamed dental pulp and its chemotactic effect on dental pulp cells

High mobility group box 1 protein (HMGB1) is a chromatin protein which can be released extracellularly, eliciting a pro-inflammatory response and promoting tissue repair process. This study aimed to examine the expression and distribution of HMGB1 and its receptor RAGE in inflamed dental pulp tissues, and to assess its effects on proliferation, migration and cytoskeleton of cultured human dental pulp cells (DPCs). Our data demonstrated that cytoplasmic expression of HMGB1 was observed in inflamed pulp tissues, while HMGB1 expression was confined in the nuclei in healthy dental pulp. The mRNA expression of HMGB1 and RAGE were significantly increased in inflamed pulps. In in vitro cultured DPCs, expression of HMGB1 in both protein and mRNA level was up-regulated after treated with lipopolysaccharide (LPS). Exogenous HMGB1 enhanced DPCs migration in a dose-dependent manner and induced the reorganization of f-actin in DPCs. Our results suggests that HMGB1 are not only involved in the process of dental pulp inflammation, but also play an important role in the recruitment of dental pulp stem cells, promoting pulp repair and regeneration.