Ketamine attenuates high mobility group box-1–induced inflammatory responses in endothelial cells

Effects of esketamine on postoperative negative emotions and early cognitive disorders in patients undergoing non-cardiac thoracic surgery: A randomized controlled trial

STUDY OBJECTIVE

To investigate whether a single dosage of esketamine injection in the anesthesia period could improve postoperative negative emotions and early cognitive function in patients undergoing non-cardiac thoracic surgery.

DESIGN

A prospective single center double blinded randomized placebo-controlled trial.

SETTING

Perioperative period; operating room, post anesthesia care unit and hospital ward.

PATIENTS

129 adult patients that underwent elective non-cardiac thoracic surgery under general anesthesia.

INTERVENTIONS

During the operation, pharmacologic prevention of postoperative negative emotion and early cognitive disorder with 0.2 mg/kg (Low esketamine group) and 0.5 mg/kg esketamine (High esketamine group) vs. placebo.

MEASUREMENTS

Emotion and early cognitive performance were assessed on the day before surgery (POD-1), postoperative day 1 (POD1) and day 3 (POD3) using HADS-A, HADS-D, Pain Visual Analogue Scale (VAS), Confusion Assessment Method (CAM), Mini-Mental State Examination (MMSE), and serum biomarkers (S100β, BDNF, IL-6, acetylcholine, and norepinephrine).

MAIN RESULTS

The high esketamine group showed significantly lower HADS-A and HADS-D scores than control group on POD1 and POD3. No significant differences were observed between the low esketamine group and the control group. The esketamine-treated groups showed lower pain VAS scores than the control group at 2 h and on the first day after operation. There were no significant differences among the three groups in CAM and MMSE scores. However, the high esketamine group had lower S100β and IL-6 levels, and higher BDNF levels postoperatively, while serum acetylcholine and norepinephrine were not significantly different.

CONCLUSIONS

A single intraoperative injection of 0.5 mg/kg esketamine can alleviate postoperative anxiety, depression, and pain to some extent. Although cognitive function behavioral evaluation did not show obvious benefits, it can also reduce the production of pro-inflammatory and brain injury-related factors while promoting the generation of brain-derived neurotrophic factor. Registration Trial registry: http://www.chictr.org.cn/; Identifier: ChiCTR2100047067.

Dexmedetomidine compared to low-dose ketamine better protected not only the brain but also the lungs in acute ischemic stroke

BACKGROUND

Dexmedetomidine (DEX) and low-dose ketamine (KET) present neuroprotective effects in acute ischemic stroke (AIS); however, to date, no studies have evaluated which has better protective effects not only on the brain but also lungs in AIS.

METHODS

AIS-induced Wistar rats (390 ± 30 g) were randomized after 24-h, receiving dexmedetomidine (STROKE-DEX, n = 10) or low-dose S(+)-ketamine (STROKE-KET, n = 10). After 1-h protective ventilation, perilesional brain tissue and lungs were removed for histologic and molecular biology analysis. STROKE animals (n = 5), receiving sodium thiopental but not ventilated, had brain and lungs removed for molecular biology analysis. Effects of DEX and KET mean plasma concentrations on alveolar macrophages, neutrophils, and lung endothelial cells, extracted primarily 24-h after AIS, were evaluated.

RESULTS

In perilesional brain tissue, apoptosis did not differ between groups. In STROKE-DEX, compared to STROKE-KET, tumor necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1) expressions were reduced, but no changes in nuclear factor erythroid 2-related factor-2 (Nrf2) and super oxide dismutase (SOD)-1 were observed. In lungs, TNF-α and VCAM-1 were reduced, whereas Nrf2 and SOD-1 were increased in STROKE-DEX. In alveolar macrophages, TNF-α and inducible nitric oxide synthase (M1 macrophage phenotype) were lower and arginase and transforming growth factor-β (M2 macrophage phenotype) higher in STROKE-DEX. In lung neutrophils, CXC chemokine receptors (CXCR2 and CXCR4) were higher in STROKE-DEX. In lung endothelial cells, E-selectin and VCAM-1 were lower in STROKE-DEX.

CONCLUSIONS

In the current AIS model, dexmedetomidine compared to low-dose ketamine reduced inflammation and endothelial cell damage in both brain and lung, suggesting greater protection.

A retrospect and outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy

Studies on the neuroprotective effects of anesthetics were carried out more than half a century ago. Subsequently, many cell and animal experiments attempted to verify the findings. However, in clinical trials, the neuroprotective effects of anesthetics were not observed. These contradictory results suggest a mismatch between basic research and clinical trials. The Stroke Therapy Academic Industry Roundtable X (STAIR) proposed that the emergence of endovascular thrombectomy (EVT) would provide a proper platform to verify the neuroprotective effects of anesthetics because the haemodynamics of patients undergoing EVT is very close to the ischaemia–reperfusion model in basic research. With the widespread use of EVT, it is necessary for us to re-examine the neuroprotective effects of anesthetics to guide the use of anesthetics during EVT because the choice of anesthesia is still based on team experience without definite guidelines. In this paper, we describe the research status of anesthesia in EVT and summarize the neuroprotective mechanisms of some anesthetics. Then, we focus on the contradictory results between clinical trials and basic research and discuss the causes. Finally, we provide an outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy.

Low-dose ketamine inhibits neuronal apoptosis and neuroinflammation in PC12 cells via α7nAChR mediated TLR4/MAPK/NF-κB signaling pathway

Ketamine is commonly used for sedation, analgesia and anesthetics. Much evidence has shown that it has an immune-regulatory effect. The cholinergic anti-inflammatory pathway mediated by α7nAChR is a prominent target of anti-inflammatory therapy. However, whether ketamine suppresses inflammatory levels in nerve cells by activating α7nAChR remains unknown. Lipopolysaccharide (LPS) was used to establish the neuroinflammation model in PC12 cells in vitro, and α7nAChR siRNA was transfected into PC12 cells 30 min before LPS to inhibit gene expression of α7nAChR. PC12 cells were stimulated with LPS for 24 h, and the indicators were detected at 2 h after GTS-21 and ketamine were added. The results showed that LPS increased the proportion of PC12 cells apoptosis, activated TLR4/MAPK/NF-κB signaling pathway, and increased the expression of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Ketamine reduced the ratio of early apoptosis and late apoptosis of PC12, inhibited the entry of P65 into the nucleus, decreased the activation of TLR4/MAPK/NF-κB and improved neuroinflammation. However, the ameliorating effects of ketamine on neuronal apoptosis and neuroinflammation were inhibited in the α7nAChRi group. This indicated that α7nAChR played a key role in the anti-inflammatory process of ketamine. Low-dose ketamine inhibited TLR4/MAPK/NF-κB by activating the α7nAChR-mediated cholinergic anti-inflammatory pathway, thereby producing the protective effect on neuronal apoptosis and neuroinflammation.

Anesthetics mediated the immunomodulatory effects via regulation of TLR signaling

Anesthetics have been widely used in surgery and found to suppress inflammatory injury and affect the outcomes of the surgery and diseases. In contrast, anesthetics are also found to induce neuronal injury and inflammation. However, the immune-modulation mechanism of anesthetics is still not clear. Recent studies have shown that the immune-modulation of anesthetics is associated with the regulation of toll-like receptor (TLR)-mediated signaling. Moreover, the regulation of anesthetics in TLR signaling is related to modulations of non-coding RNAs (nc RNAs). Consistently, nc RNAs are mainly divided into micro RNAs (miRs) and long non-coding RNAs (lnc RNAs), which have been found to exert regulatory effects on the immune system. In this review, we summarize the immunomodulatory functions of the widely used anesthetic agents, which are associated with regulation of TLR signaling. In addition, we also focus on the roles of nc RNAs induced by anesthetics in regulations of TLR signaling.

A cross-sectional study of vitreous and serum high mobility group box-1 levels in proliferative diabetic retinopathy

PURPOSE

We determined vitreous and serum levels of high mobility group box-1 (HMGB-1) in patients with proliferative diabetic retinopathy (PDR) and elucidate their relationship with receptor for advanced glycation end products (RAGE), vascular endothelial growth factor (VEGF) and interleukin-1β (IL-1β).

METHODS

In this cross-sectional study, patients with PDR who underwent vitrectomy were enrolled, and the control group included non-diabetic eyes. Vitreous and serum samples were analysed for HMGB-1, RAGE, VEGF and IL-1β by ELISA. We investigated the correlation between serum and vitreous levels of each cytokine, and we analysed the influence of intravitreal anti-VEGF treatment prior to vitrectomy on the cytokine levels in PDR.

RESULTS

Of 78 eyes of 78 patients enrolled consecutively, there were 32 PDR eyes and 46 control eyes. The serum levels were higher in diabetic than in non-diabetic subjects for HMGB-1, RAGE, VEGF and IL-1β (all p < 0.001), respectively. Similarly, the vitreous levels were higher in diabetic than in non-diabetic subjects for HMGB-1 (p < 0.001), RAGE (p = 0.001), VEGF (p < 0.001) and IL-1β (p < 0.001), respectively. We found a positive correlation between serum and vitreous levels of HMGB-1 in patient with PDR (p = 0.047, R = 0.353). There was a negative correlation between serum and vitreous levels of VEGF in patient with PDR (p = 0.001, R = -0.546). For the subgroup analysis, we detected that the vitreous levels of RAGE were significantly lower in patients who underwent anti-VEGF injection prior to vitrectomy than those who did not (p < 0.001).

CONCLUSIONS

Our findings suggest that HMGB-1 is involved in PDR disorders, and it may be a novel therapeutic target to inhibit progression of PDR.

Nonanesthetic Effects of Ketamine: A Review Article

Ketamine is considered a dissociative anesthetic medication, and it is commonly administered by a parenteral route. It works mainly by blocking the N-methyl-D-aspartate receptor. It inhibits the voltage-gated Na and K channels and serotonin and dopamine reuptake; also, it affects specific receptors, such as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, and aminobutyric acid A receptors. Ketamine appears to have particular mechanisms that are potentially involved during analgesic induction, including enhancing of descending inhibition and antiinflammatory effects. More recently, it has been shown that ketamine has potential in clinical practice for the management of chronic pain, cognitive function, depression, acute brain injury, and disorders of the immune system.

In Vogue: Ketamine for Neuroprotection in Acute Neurologic Injury

Neurologic deterioration following acute injury to the central nervous system may be amenable to pharmacologic intervention, although, to date, no such therapy exists. Ketamine is an anesthetic and analgesic emerging as a novel therapy for a number of clinical entities in recent years, including refractory pain, depression, and drug-induced hyperalgesia due to newly discovered mechanisms of action and new application of its known pharmacodynamics. In this focused review, the evidence for ketamine as a neuroprotective agent in stroke, neurotrauma, subarachnoid hemorrhage, and status epilepticus is highlighted, with a focus on its applications for excitotoxicity, neuroinflammation, and neuronal hyperexcitability. Preclinical modeling and clinical applications are discussed.

MicroRNA-142-3p inhibits hypoxia/reoxygenation‑induced apoptosis and fibrosis of cardiomyocytes by targeting high mobility group box 1

Myocardial ischemia/reperfusion (I/R) injury may cause the apoptosis of cardiomyocytes as well as cardiac fibrosis, which is characterized as the transdifferentiation of fibroblasts to myofibroblasts and collagen deposition. MicroRNAs (miRNAs or miRs) have been demonstrated to be involved in myocardial I/R injury. However, the underlying molecular mechanism remains largely unclear. In the present study, mouse cardiomyocyte M6200 cells were treated with hypoxia/reoxygenation (H/R). Our data indicated that H/R treatment led to cell apoptosis, the increased expression of fibrosis-related proteins, namely collagen I, II, III, and fibronectin, as well as the downregulation of miR-142-3p in M6200 cells. Overexpression of miR-142-3p suppressed the H/R-induced apoptosis and fibrosis of M6200 cells. Bioinformatics analysis and a Dual-Luciferase reporter assay further identified high mobility group box 1 (HMGB1) as a direct target gene of miR-142-3p, and miR-142-3p negatively regulated the protein level of HMGB1 in M6200 cells. Furthermore, knockdown of HMGB1 enhanced cell proliferation whereas it inhibited the apoptosis and fibrosis of M6200 cells. In addition, TGF-β1/Smad3 signaling was suggested to be involved in the miR-142-3p/HMGB1-mediated apoptosis and fibrosis of M6200 cells treated with H/R. Taken together, the findings of the present study demonstrate that miR-142-3p inhibits H/R-induced apoptosis and fibrosis of cardiomyocytes, partly at least, by the direct inhibition of HMGB1 expression. Therefore, these findings have increased our understanding of the pathogenesis of H/R-induced myocardial injury.