Stellate ganglion block alleviates postoperative cognitive dysfunction via inhibiting TLR4/NF-κB signaling pathway.

Postoperative cognitive dysfunction (POCD) is common in aged patients after major surgery and is associated with increased risk of long-term morbidity and mortality. However, the underlying mechanism remains largely unknown and the clinical management of POCD is still controversial. Stellate ganglion block (SGB) is a clinical treatment for nerve injuries and circulatory issues. Recent evidence has identified the benefits of SGB in promoting learning and memory. We thus hypothesize that SGB could be effective in improving cognitive function after surgery. In present study, we established POCD model in aged rats via partial liver resection surgery. We found that the development of POCD was associated with the activation of toll-like receptor 4/nuclear factor kapa-B (TLR4/NF-κB) signaling pathway in the microglia in dorsal hippocampus, which induced the production of pro-inflammatory mediators (TNF-α, IL-1ß, IL-6) and promoted neuroinflammation. More importantly, we showed evidence that preoperative treatment with SGB could inhibit microglial activation, suppress TLR4/NF-κB-mediated neuroinflammation and effectively attenuate cognitive decline after the surgery. Our study suggested that SGB may serve as a novel treatment to prevent POCD in elderly patients. As SGB is safe procedure widely used in clinic, our findings can be easily translated into clinical practice and benefit more patients.

Dexmedetomidine inhibits mitochondria damage and apoptosis of enteric glial cells in experimental intestinal ischemia/reperfusion injury via SIRT3-dependent PINK1/HDAC3/p53 pathway.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) injury commonly occurs during perioperative periods, resulting in high morbidity and mortality on a global scale. Dexmedetomidine (Dex) is a selective α2-agonist that is frequently applied during perioperative periods for its analgesia effect; however, its ability to provide protection against intestinal I/R injury and underlying molecular mechanisms remain unclear. METHODS: To fill this gap, the protection of Dex against I/R injury was examined in a rat model of intestinal I/R injury and in an inflammation cell model, which was induced by tumor necrosis factor-alpha (TNF-α) plus interferon-gamma (IFN-γ) stimulation. RESULTS: Our data demonstrated that Dex had protective effects against intestinal I/R injury in rats. Dex was also found to promote mitophagy and inhibit apoptosis of enteric glial cells (EGCs) in the inflammation cell model. PINK1 downregulated p53 expression by promoting the phosphorylation of HDAC3. Further studies revealed that Dex provided protection against experimentally induced intestinal I/R injury in rats, while enhancing mitophagy, and suppressing apoptosis of EGCs through SIRT3-mediated PINK1/HDAC3/p53 pathway in the inflammation cell model. CONCLUSION: Hence, these findings provide evidence supporting the protective effect of Dex against intestinal I/R injury and its underlying mechanism involving the SIRT3/PINK1/HDAC3/p53 axis.

KDM4B promotes DNA damage response via STAT3 signaling and is a target of CREB in colorectal cancer cells.

Resistance to radiotherapy is a major limitation for the successful treatment of colorectal cancer (CRC). Recently, accumulating evidence supports a critical role of epigenetic regulation in tumor cell survival upon irradiation. Lysine Demethylase 4B (KDM4B) is a histone demethylase involved in the oncogenesis of multiple human cancers but the underlying mechanisms have not been fully elucidated. Here we show that KDM4B is overexpressed in human colorectal cancer (CRC) tumors and cell lines. In CRC cells, KDM4B silencing induces spontaneous double-strand breaks (DSBs) formation and potently sensitizes tumor cells to irradiation. A putative mechanism involved suppression of Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway, which is essential for efficient repair of damaged DNA. Overexpression of STAT3 in KMD4B knockdown cells largely attenuates DNA damage triggered by KDM4B silencing and increases cell survival upon irradiation. Moreover, we find evidence that transcription factor CAMP Responsive Element Binding Protein (CREB) is a key regulator of KMD4B expression by directly binding to a conserved region in KMD4B promoter. Together, our findings illustrate the significance of CREB-KDM4B-STAT3 signaling cascade in DNA damage response, and highlight that KDM4B may potentially be a novel oncotarget for CRC radiotherapy.

Dexmedetomidine promotes the recovery of neurogenesis in aged mouse with postoperative cognitive dysfunction.

Recently, growing evidence has demonstrated Dexmedetomidine (Dex) a promising intervene preventing postoperative cognitive decline (POCD) following surgery, which is associated with neuroinflammation leading to neuronal apoptosis and deregulated neurogenesis. Previous studies suggested the anti-inflammation and anti-neuroapoptosis action of Dex. Therefore we hypothesize the promoting neurogenesis of Dex linked to stimulating BDNF and subsequent p-MPAK production in a rat model of POCD. In the present study, the POCD animal model was established by performing an exploratory laparotomy under isoflurane anaesthesia in old rats, utilizing which Dex response is confirmed by behavioural tests. Inflammatory biomarkers as IL-1ß and TNF-α, mature neuron percentage measured by doublecortin staining (DCX), promoting factors as brain derived growth factor (BDNF), phosphorylated cAMP response element binding protein (CREB) and proteins of kinase A (PKA), MAPK production as p-P38-MAPK protein express were measured. Herein, we showed that surgery reduced DCX-positive neurons and expression of BDNF representing neurogenesis profoundly. As expected, Dex rescued the associated cognitive impairment and inflammatory changes, as well as up-regulated expression of BDNF, PKA, p-CREB/CREB and following p-P38-MAPK regulation. Our results confirmed the protective Dex response and indicated the proneurogenesis role of it as well, suggesting the mechanism of beneficial effects of Dex to prevent POCD.

Evaluation of dexmedetomidine in combination with sufentanil or butorphanol for postoperative analgesia in patients undergoing laparoscopic resection of gastrointestinal tumors: A quasi-experimental trial.

The aim of this study was to evaluate the efficacy of dexmedetomidine in combination with sufentanil or butorphanol for postoperative analgesia in patients undergoing laparoscopic resection of a gastrointestinal tumor.This quasi-experimental trial was conducted in Nanchang, China, from January 2014 to December 2015. Eighty patients (age 27-70 years, American Society of Anesthesiologists physical status I-II) undergoing laparoscopic resection of a gastrointestinal tumor were randomized into 4 groups and offered intravenous patient-controlled analgesia for pain control after surgery. The patients received sufentanil 2.0 µg/kg in combination with dexmedetomidine 1.5 µg/kg (group S1) or 2.0 µg/kg (group S2), or butorphanol 0.15 mg/kg in combination with dexmedetomidine 1.5 0 µg/kg (group N1) or 2.0 µg/kg (group N2). Oxygen saturation, mean arterial pressure (MAP), heart rate, visual analog scale score, and Ramsay sedation score were recorded at enrollment (T0), at extubation (T1), and 4 (T2), 8 (T3), 12 (T4), 24 (T5), and 48 (T6) hours thereafter. Side effects and satisfaction scores were evaluated after surgery.MAP increased in all groups at T1 but not significantly so when compared with T0. Heart rate decreased significantly in group S2 when compared with the other groups at T1-T5 (P < 0.05). MAP decreased significantly in group S2 when compared with group S1 at T4-T6 (P < 0.05). MAP increased significantly in group N1 when compared with group N2 at T4-T5 (P < 0.05). There was a statistically significant decrease in mean visual analog scale score in group S2 when compared with group S1 at T2 (P < 0.05) and group N2 at T1-T2 (P < 0.05). Two patients in group S1 had vomiting. There were no reports of drowsiness, respiratory depression, or other complications. The satisfaction score was higher in group S2 than in the other groups.Dexmedetomidine in combination with sufentanil or butorphanol can be used safely and effectively for postoperative analgesia in patients undergoing laparoscopic resection of a gastrointestinal tumor. The combination of dexmedetomidine 2.0 µg/kg and sufentanil is particularly beneficial in these patients.