Dexmedetomidine Ameliorated Cognitive Dysfunction Induced by Intestinal Ischemia Reperfusion in Mice with Possible Relation to the Anti-inflammatory Effect Through the Locus Coeruleus Norepinephrine System

Dexmedetomidine alleviates intestinal ischemia/reperfusion injury by modulating intestinal neuron autophagy and mitochondrial homeostasis via Nupr1 regulation

Intestinal ischemia/reperfusion injury (I/R) is a common yet challenging-to-treat condition, presenting a significant clinical challenge. This study aims to investigate the protective mechanisms of Dexmedetomidine (Dex) against I/R injury, with a particular focus on its role in regulating autophagy activity in intestinal neurons and maintaining mitochondrial homeostasis. Experimental findings demonstrate that Dex can mitigate intestinal damage induced by I/R through the modulation of autophagy activity and mitochondrial function in intestinal neurons by suppressing the expression of Nupr1. This discovery sheds light on a new molecular mechanism underlying the potential efficacy of Dex in treating intestinal I/R injury, offering valuable insights for clinical therapy.

The Effect of Low-Dose Dexmedetomidine on Perioperative Neurocognitive Dysfunction in Elderly Patients Undergoing Endoscopic Retrograde Cholangiopancreatography (ERCP): A Randomized, Controlled, Double-Blind Trial

Objective

This study investigates the effect of low-dose dexmedetomidine infusion on perioperative neurocognitive function in elderly patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

Patients and Methods

This double-blind trial enrolled 80 elderly ERCP patients randomized to receive dexmedetomidine (Group D) or placebo (Group S). Group D received dexmedetomidine at 0.4 μg·kg-1·h-1 starting 15 minutes before surgery until completion, along with propofol at 1.5 mg/kg for anesthesia. Group S received saline and propofol in a similar manner. Anesthesia was maintained with dexmedetomidine at 0.4 μg·kg-1·h-1 and propofol at 1-2 mg/kg during surgery. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) preoperatively and on postoperative days 1, 3, and 5. Primary outcome was perioperative neurocognitive disorder (PND) incidence on day 5; secondary outcomes included changes in perioperative IL-6, cortisol, S100-β, hemodynamics, anesthesia parameters, postoperative pain, agitation scores, and adverse events.

Results

All 80 patients completed the trial. On postoperative day 5, the cumulative probability of PND incidence was significantly lower in Group D than in Group S (12.5% vs 35%, P=0.018). Group D also had lower levels of IL-6 (F=199.472, P<0.001), S100-β (F=2681.964, P<0.001), and cortisol (F=137.637, P<0.001). Propofol doses were lower in Group D (706.1 ± 202.4 vs 1003.3 ± 203.7, P<0.001), and bradycardia rates were higher (45% vs 15%, P=0.003), though atropine use did not significantly differ between groups. Group D showed greater stability in mean arterial pressure. Postoperative complications and adverse reactions were similar across groups.

Conclusion

Perioperative low-dose dexmedetomidine infusion with propofol in elderly ERCP patients ensures safe and effective monitored anesthesia care (MAC), reducing PND incidence by mitigating peripheral inflammation and stress responses. Long-term follow-up is needed to fully evaluate PND incidence.

Attenuation of intestinal ischemia-reperfusion-injury by anesthetics: a potentially protective effect of anesthetic management in experimental studies

Intestinal ischemia-reperfusion injury (IRI) is a potentially severe clinical syndrome after major surgical procedures. In addition to causing intestinal mucosa injury, intestinal IRI further damages distant organs, causing the severity of the condition in patients. So far, effective therapy for intestinal IRI is still absent, and the survival rate of the patients is low. Previous experimental studies have shown that some anesthetics can alleviate intestinal IRI and protect organs while exerting their pharmacological effects, indicating that reasonable perioperative anesthesia management may provide potential benefits for patients to avoid intestinal IRI. These meaningful findings drive scholars to investigate the mechanism of anesthetics in treating intestinal IRI in-depth to discuss the possible new clinical uses. In the present mini-review, we will introduce the protective effects of different anesthetics in intestinal IRI to help us enrich our knowledge in this area.

Dexmedetomidine alleviates ferroptosis following hepatic ischemia-reperfusion injury by upregulating Nrf2/GPx4-dependent antioxidant responses

Hepatic ischemia-reperfusion injury (HIRI) adversely affects liver transplant and resection outcomes. Recently, ferroptosis has been associated with HIRI. Dexmedetomidine (Dex), a potent sedative with anti-inflammatory, antioxidant, and anti-apoptotic properties, protects organs from hypoxic or ischemia-reperfusion (I/R) injuries. However, the mechanisms underlying this protective effect against I/R-induced liver injury remain unclear. This study evaluated the effect of Dex on HIRI in mouse models and the oxygen-glucose deprivation/reperfusion (OGD/R) AML12 cell model. We examined ferroptosis-related markers, including Fe2+ levels, reactive oxygen species (ROS) content, mitochondrial morphology, GPX4 protein expression, 4-hydroxynonenal (4-HNE), and Nrf2. The Nrf2 inhibitor ML385 was used in combination with Dex to treat HIRI mice and OGD/R-induced cellular models to explore the pathways by which Dex counteracts ferroptosis. Our results showed that Dex treatment significantly ameliorated OGD/R-induced ferroptosis in AML12 cells, including reduced Fe2+, ROS, malondialdehyde (MDA), and 4-HNE levels. Dex also ameliorated liver tissue damage and reduced serum AST, ALT, and inflammatory factor levels in HIRI mice. Additionally, Dex increased the levels of GSH, an antioxidative stress marker, and GPX4 expression in HIRI mice. Mechanistically, Nrf2 expression and nuclear translocation were significantly inhibited in both HIRI mice and OGD/R-treated AML12 cells. Dex treatment also restored the I/R-induced inhibition of Nrf2 expression and nuclear translocation. ML385 significantly inhibited Dex-promoted Nrf2 nuclear aggregation with Gpx4 protein expression, hindering the efficacy of Dex. In conclusion, Dex ameliorates ferroptosis in HIRI by positively regulating the Nrf2/GPx4 axis, potentially presenting a therapeutic avenue for addressing HIRI.

Dexmedetomidine against intestinal ischemia/reperfusion injury: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Intestinal ischemia/reperfusion injury (IRI) is a multifactorial, complex pathophysiological process in clinical settings. In recent years, intestinal IRI has received increasing attention due to increased morbidity and mortality. To date, there are no effective treatments. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, has been demonstrated to be effective against intestinal IRI. In this systematic review and meta-analysis, we evaluated the efficacy and potential mechanisms of DEX as a treatment for intestinal IRI in animal models.

METHODS

Five databases (PubMed, Embase, Web of Science, Cochrane Library, and Scopus) were searched until March 15, 2023. Using the SYRCLE risk bias tool, we assessed methodological quality. Statistical analysis was conducted using STATA 12 and R 4.2.2. We analyzed the related outcomes (mucosa damage-related indicators; inflammation-relevant markers, oxidative stress markers) relied on the fixed or random-effects models.

RESULTS

There were 15 articles including 18 studies included, and 309 animals were involved in the studies. Compared to the model groups, DEX improved intestinal IRI. DEX decreased Chiu's score and serum diamine oxidase (DAO) level. DEX reduced the level of inflammation-relevant markers (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α). DEX also improved oxidative stress (decreased malondialdehyde (MDA), increased superoxide dismutase (SOD)).

CONCLUSIONS

DEX's effectiveness in ameliorating intestinal IRI has been demonstrated in animal models. Antioxidation, anti-inflammation, anti-apoptotic, anti-pyroptosis, anti-ferroptosis, enhancing mitophagy, reshaping the gut microbiota, and gut barrier protection are possible mechanisms. However, in light of the heterogeneity and methodological quality of these studies, further well-designed preclinical studies are warranted before clinical implication.