The effects of dexmedetomidine on mesenteric arterial occlusion-associated gut ischemia and reperfusion-induced gut and kidney injury in rabbits

Haemodynamic effect of dexmedetomidine during paediatric kidney transplantation

BACKGROUND

Dexmedetomidine is increasingly used for its ability to stabilise haemodynamic status during general anaesthesia. However, there is currently no data on paediatric kidney transplant recipients (pKTR). This study investigates the haemodynamic impact of dexmedetomidine administered perioperatively in pKTR.

METHODS

From 2019 to 2023, a retrospective study was conducted at Nantes University Hospital involving all pKTR under 18 years of age. The study compared intraoperative haemodynamic parameters between patients administered dexmedetomidine during kidney transplantation (DEX group) and those who did not receive it (no-DEX group). Mean arterial pressure (MAP) and heart rate (HR) were monitored throughout the duration of anaesthesia and compared. Graft function was assessed based on creatinine levels and glomerular filtration rate (GFR) at specific intervals. The perioperative use of fluids and vasoactive drugs, as well as their administration within 24 h post-surgery, were analysed.

RESULTS

Thirty-eight patients were enrolled, 10 in the DEX group and 28 in the no-DEX group. Intraoperative HR was similar between the groups; however, MAP was higher in the DEX group (mean difference 9, standard deviation (SD, 1-11) mmHg, p = 0.039). No differences were found regarding the use of fluid and vasoactive drug therapy between groups. GFR at 1 month post-transplantation was significantly elevated in the DEX group (p = 0.009).

CONCLUSIONS

pKTR receiving intraoperative dexmedetomidine exhibited higher perioperative MAP compared to those not administered dexmedetomidine. Additionally, the DEX group demonstrated superior graft function at 1 month. The direct impact of dexmedetomidine on immediate postoperative graft function in pTKR warrants further investigation in a prospective multicentre randomised study.

Dexmedetomidine preconditioning reduces ischaemia-reperfusion injury in equine model of large colon volvulus

BACKGROUND

Large colon volvulus is a cause of colic in horses with high morbidity and mortality when not promptly treated. More treatment options are needed to improve the outcome of these cases by protecting against the damage caused by ischaemia and reperfusion injury.

OBJECTIVES

To determine the effect of preconditioning with dexmedetomidine prior to induction of ischaemia-reperfusion (IR) injury in a large colon volvulus model in the horse.

STUDY DESIGN

Randomised blinded in vivo experiments.

METHODS

Horses received either a dexmedetomidine (DEX) or saline (CON) constant rate infusion (CRI) immediately following induction of anaesthesia. Venous, arterial, and transmural occlusion of a section of the large colon was performed for 3 h, after which the ligatures and clamps were removed to allow for reperfusion for 3 h. Biopsies of the large colon were taken at baseline, 1 and 3 h of ischaemia, and at 1 and 3 h of reperfusion.

RESULTS

The severity of crypt epithelial loss (DEX = 2.1 [0.8-2.8], CON = 3.1 [2.5-4], p = 0.03) and mucosal haemorrhage was decreased (DEX = 2.1 [1.3-3], CON = 3.5 [2.5-4], p = 0.03) in group DEX compared to group CON when graded on a scale of 0-4. Crypt length remained longer (DEX = 369.5 ± 91.7 μm, CON = 238.5 ± 72.6 μm, p = 0.02) and interstitium to crypt (I:C) ratio remained lower (DEX = 1.4 (1-1.7), CON = 2.6 [1.8-5.9], p = 0.03) in group DEX compared to group CON during reperfusion.

MAIN LIMITATIONS

Clinical applicability of pharmacologic preconditioning is limited.

CONCLUSION

Preconditioning with a dexmedetomidine CRI prior to IR injury demonstrated a protective effect histologically on the large colon in the horse. Further investigation into postconditioning with dexmedetomidine is warranted as a possible intervention in colic cases suspected of being large colon volvulus.

Perioperative acute kidney injury: The renoprotective effect and mechanism of dexmedetomidine

Dexmedetomidine (DEX) is a highly selective and potent α2-adrenoceptor (α2-AR) agonist that is widely used as a clinical anesthetic to induce anxiolytic, sedative, and analgesic effects. In recent years, a growing body of evidence has demonstrated that DEX protects against acute kidney injury (AKI) caused by sepsis, drugs, surgery, and ischemia-reperfusion (I/R) in organs or tissues, indicating its potential role in the prevention and treatment of AKI. In this review, we summarized the evidence of the renoprotective effects of DEX on different models of AKI and explored the mechanism. We found that the renoprotective effects of DEX mainly involved antisympathetic effects, reducing inflammatory reactions and oxidative stress, reducing apoptosis, increasing autophagy, reducing ferroptosis, protecting renal tubular epithelial cells (RTECs), and inhibiting renal fibrosis. Thus, the use of DEX is a promising strategy for the management and treatment of perioperative AKI. The aim of this review is to further clarify the renoprotective mechanism of DEX to provide a theoretical basis for its use in basic research in various AKI models, clinical management, and the treatment of perioperative AKI.

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.

Alpha2 Antagonist Vatinoxan Does Not Abolish the Preconditioning Effect of Dexmedetomidine on Experimental Ischaemia-Reperfusion Injury in the Equine Small Intestine

Pharmacological preconditioning with dexmedetomidine has been shown to ameliorate intestinal ischaemia reperfusion injury in different species, including horses. However, it remains unknown if this effect is related to alpha2 adrenoreceptor activity. Therefore, the aim of this study was to determine the effect of dexmedetomidine preconditioning with and without the administration of the peripheral alpha2 antagonist vatinoxan. This prospective randomized experimental trial included 12 horses equally divided between two treatment groups. Horses in group Dex received a bolus of dexmedetomidine followed by a continuous rate infusion (CRI), while group DexV additionally received vatinoxan as bolus and CRI. A median laparotomy was performed under general anaesthesia, and jejunal ischaemia was applied for 90 min, followed by 30 min of reperfusion. Mucosal damage was evaluated in full thickness biopsies by use of a semiquantitative mucosal injury score and by determining the apoptotic cell counts with immunohistochemical staining for cleaved caspase-3 and TUNEL. Comparisons between the groups and time points were performed using non-parametric tests (p < 0.05). During pre-ischaemia and ischaemia, no differences could be found in mucosal injury between the groups. After reperfusion, group DexV showed lower mucosal injury scores compared to group Dex. The apoptotic cell counts did not differ between the groups. In conclusion, antagonizing the peripheral alpha2 adrenoreceptors did not negatively affect dexmedetomidine preconditioning.

Relationship between the postoperative lactate dynamic levels, the acute gastrointestinal injury and the prognosis among patients who undergo surgical treatment for acute type A aortic dissection

Introduction

This study aimed to determine the relationship between the postoperative lactate dynamic levels, the postoperative acute gastrointestinal injury (AGI), and the prognosis among the patients who underwent surgical treatment for an acute Stanford type-A aortic dissection (aTAAD).

Methods

A total of 271 aTAAD patients were recruited and monitored. Of the 271 aTAAD patients, 29.2% developed an AGI and were designated as the AGI group (n = 79); the other patients (n = 192) were designated as the non-AGI group. According to the 2-year follow up, the aTAAD patients were also divided into the alive and death subgroups for further analysis.

Results

Binary logistic regression analysis revealed that the postoperative 4-h lactate (P4L) level, time-to-return to the normal blood lactate level (TRNL), postoperative 16-h lactate (P16L) level, and neutrophil granulocyte (NEU) count had a good predictive value for an AGI after aTAAD. The 8-week and 2-year mortality rates were higher in the AGI group than the non-AGI group (P < 0.05). Basic data and clinical characteristics were significantly different between the alive and death groups (P < 0.05). A higher AGI rate and mortality occurred in the P4L level ≥10.15 mmol/L subgroup, TRNL ≥21-h subgroup, P16L level ≥2.95 mmol/L subgroup, NEU count ≥10.9 × 10⁹/L subgroup, PaO₂ < 77.7 mmHg subgroup, WBC count ≥9.58 × 10⁹/L subgroup, and the operative time ≥427 min subgroup than the corresponding comparison subgroups (P < 0.05). The postoperative 0-h lactate (P0L) level, TRNL, postoperative 24-h lactate (P24L) level, D-dimer level, fibrinogen degradation products (FDP) level, duration of mechanical ventilation, and length of hospitalization were independent factors influencing the 30-day mortality rate in patients who underwent surgery for an aTAAD (P < 0.05). Cox regression multivariate analysis after univariate analysis of all-cause mortality showed the TRNL, postoperative 12-h lactate (P12L) level, P16L level, P24L level, D-dimer level, FDP level, and length of hospitalization were independently associated with the 2-year mortality rate in patients who underwent surgery for an aTAAD (P < 0.05).

Conclusion

The postoperative lactate changes and TRNL effectively predicted postoperative AGI and the mortality rate in patients with who underwent surgery for an aTAAD. The TRNL and P24L level were independent risk factors for the 30-day and 2-year mortality rates in patients who underwent surgery for an aTAAD.

Abdominal Organ Transplantation: Noteworthy Literature in 2022

This review highlights noteworthy literature published in 2022 pertinent to anesthesiologists and critical care physicians caring for patients undergoing abdominal organ transplantation. We begin by exploring the impacts that the COVID-19 pandemic has had across the field of abdominal organ transplantation, including the successful use of grafts procured from COVID-19-infected donors. In pancreatic transplantation, we highlight several studies on dexmedetomidine and ischemia-reperfusion injury, equity in transplantation, and medical management, as well as studies comparing pancreatic transplantation to islet cell transplantation. In our section on intestinal transplantation, we explore donor selection. Kidney transplantation topics include cardiovascular risk management, obesity, and intraoperative management, including fluid resuscitation, dexmedetomidine, and sugammadex. The liver transplantation section focuses on clinical trials, systematic reviews, and meta-analyses published in 2022 and covers a wide range of topics, including machine perfusion, cardiovascular issues, renal issues, and coagulation/transfusion.

Dexmedetomidine improves acute lung injury by activating autophagy in a rat hemorrhagic shock and resuscitation model

Dexmedetomidine (DEX) can reduce lung injury in a hemorrhagic shock (HS) resuscitation (HSR) model in rats by inhibiting inflammation. Here, we aimed to investigate if these effects of DEX are due to autophagy activation. Therefore, we established HSR rat models and divided them into four groups. HS was induced using a blood draw. The rats were then resuscitated by reinjecting the drawn blood and saline. The rats were sacrificed 24 h after resuscitation. Lung tissues were harvested for histopathological examination, determination of wet/dry lung weight ratio, and detection of the levels of autophagy-related marker proteins LC3, P62, Beclin-1, and the ATG12-ATG5 conjugate. The morphological findings of hematoxylin and eosin staining in lung tissues and the pulmonary wet/dry weight ratio showed that lung injury improved in HSR + DEX rats. However, chloroquine (CQ), an autophagy inhibitor, abolished this effect. Detecting the concentration of autophagy-related proteins showed that DEX administration increased LC3, ATG12-ATG5, and Beclin-1 expression and decreased P62 expression. The expression levels of these proteins were similar to those in the HSR group after CQ + DEX administration. In summary, DEX induced autophagic activation in an HSR model. These findings suggest that DEX administration partially ameliorates HSR-induced lung injury via autophagic activation.

Dexmedetomidine attenuates hepatic ischemia-reperfusion injury-induced apoptosis via reducing oxidative stress and endoplasmic reticulum stress

Dexmedetomidine (DEX) affords a hepatoprotective effect during ischemia-reperfusion (IR) injury (IRI); however, the underlying mechanism remains elusive. In this work, using a rat liver IR model and a BRL-3A cell hypoxia-reoxygenation (HR) model, we explored whether DEX protects the liver against IRI by decreasing oxidative stress (OS), endoplasmic reticulum stress (ERS), and apoptotic pathways. We found that DEX significantly increased SOD and GSH activity while decreasing ROS and MDA levels in BRL-3A cells, successfully preventing HR-induced OS damage. DEX administration reduced JNK, ERK, and P38 phosphorylation and blocked HR-induced MAPK signaling pathway activation. Additionally, DEX administration reduced the expression of GRP78, IRE1α, XBP1, TRAF2, and CHOP, which reduced HR-induced ERS. NAC prevented the MAPK pathway from being activated and inhibited the ERS pathway. Further research showed that DEX significantly reduced HR-induced apoptosis by suppressing the expression of Bax/Bcl-2 and cleaved caspase-3. Similarly, animal studies demonstrated DEX exerted a protective effect of the liver by alleviating histopathological injury and enhancing liver function, mechanically DEX reduced cell apoptosis in liver tissue by reducing oxidative stress and ERS. In conclusion, DEX mitigates OS and ERS during IR, thereby suppressing cell apoptosis, thus providing protection to the liver.

Effects of perioperative dexmedetomidine infusion on renal function and microcirculation in kidney transplant recipients: a randomised controlled trial

OBJECTIVE

Ischemia-reperfusion injury affects postoperative transplanted kidney function in kidney transplant recipients. Dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation, but its propensity to cause bradycardia and hypotension may adversely affect microcirculation. This study investigated the effect of dexmedetomidine on postoperative renal function and sublingual microcirculation in kidney recipients.

METHODS

The enrolled kidney transplant recipients were randomly allocated to the control group or dexmedetomidine group. After anaesthesia induction, patients in the dexmedetomidine group received dexmedetomidine infusion until 2 h after surgery. Sublingual microcirculation was recorded using an incident dark-field video microscope and analysed. The primary outcomes were the creatinine level on a postoperative day 2 and total vessel density at 2 h after surgery.

RESULTS

A total of 60 kidney recipients were analysed, and the creatinine levels on postoperative day 2 were significantly lower in the dexmedetomidine group than in the control group (1.5 (1.1-2.4) vs. 2.2 (1.7-3.0) mg/dL, median difference -0.6 (95% CI, -0.7 to -0.5) mg/dL, p = .018). On a postoperative day 7, the creatinine levels did not differ significantly between the two groups. Total vessel density at 2 h after surgery did not differ significantly between the two groups.

CONCLUSION

We found that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine infusion, but total vessel density was not significantly different between the intervention and control groups. Key messagesIschemia-reperfusion injury affects postoperative transplanted kidney function, and dexmedetomidine was reported to attenuate ischemia-reperfusion injury and improve microcirculation in other clinical conditions.This study showed that early postoperative renal function was better in kidney transplant recipients receiving dexmedetomidine.Dexmedetomidine's side effect of bradycardia and hypotension may affect microcirculation, our results revealed that the perioperative sublingual microcirculation did not differ significantly in kidney transplant recipients receiving dexmedetomidine.

The effects of dexmedetomidine for patient-controlled analgesia on postoperative sleep quality and gastrointestinal motility function after surgery: A prospective, randomized, double-blind, and controlled trial

Background: Postoperative poor sleep quality and decreased gastrointestinal motility function are common clinical problems. This study investigated the effects of dexmedetomidine (DEX) combined with sufentanil for patient-controlled analgesia (PCA) on postoperative sleep quality and gastrointestinal motility function after surgery in patients with colorectal cancer.

Methods: Patients undergoing colorectal cancer surgery were randomly divided into three groups, DEX 0, 200, or 400 μg, each combined with sufentanil 150 μg for PCA immediately after surgery. The primary outcome was sleep quality in the first 7 days after surgery based on the Athens Insomnia Scale (AIS) score. The secondary outcome was postoperative gastrointestinal motility recovery evaluated by the time of first flatus, first feces and first diet. Postoperative pain intensity, side effects and the length of postoperative hospital stay were also compared among groups. The study was registered with the Chinese Clinical Trial Registry (https://www.chictr.org.cn/enIndex.aspx, ChiCTR2000032601).

Results: Ultimately, 210 cases were included. Sleep quality was better in the DEX 200 μg group and DEX 400 μg group than in the DEX 0 μg group. Overall, in the DEX 200 μg group and DEX 400 μg group, the AIS score (p < 0.05) and the incidence of sleep disturbance (7.3%, 4.5% vs. 19.6%, p < 0.001) were lower than those in the DEX 0 μg group in the first 7 days after surgery. There were no significant differences in postoperative gastrointestinal motility among the three groups in the total surgical categories (p > 0.05). In the laparoscopic surgery patients of each group, the time of postoperative first flatus (p = 0.02) and first feces (p = 0.01) was significantly longer in the DEX 400 μg group than in the DEX 0 μg group. There were no differences in postoperative pain intensity, side effects or length of postoperative hospital stay (p > 0.05).

Conclusion: The continuous infusion of DEX (200 or 400 μg) for PCA significantly improved postoperative sleep quality after colorectal cancer surgery. DEX (200 μg) was better at improving postoperative sleep quality without affecting gastrointestinal motility function than DEX (400 μg) in patients who underwent laparoscopic colorectal cancer surgery.

Dexmedetomidine postconditioning provides renal protection in patients undergoing laparoscopic partial nephrectomy: A randomized controlled trial

Background: For localized disease, partial nephrectomy of small tumors continues to be the gold-standard treatment. However, temporary clamping is routinely performed during this process to control renal blood flow, which can cause renal ischemic/reperfusion injury. We evaluated whether dexmedetomidine postconditioning (DPOC) can reduce renal ischemic/reperfusion injury for patients receiving laparoscopic partial nephrectomy (LPN).

Methods: This randomized double-blind controlled trial included 77 patients who were scheduled for LPN at our hospital. Patients were randomly allocated to the DPOC or control group. DPOC was performed via intravenous administration of dexmedetomidine at 0.6 μg kg−1 for 10 min immediately after unclamping the renal artery. In the control group, saline was administered in place of dexmedetomidine under the same protocol. All participants underwent a 6-month follow-up. The primary outcome were the values of 99mTc-DTPA-GFR in the affected kidney at one and 6 months post-LPN.

Result: The GFR values in the DPOC group (35.65 ± 4.89 ml min−1.1.73 m−2) were significantly higher than those the control group (33.10 ± 5.41 ml min−1.1.73 m−2; p = 0.022) at 1 month after LPN. There was no statistically significant difference in GFR value between the two groups at 6 months after LPN.

Conclusion: DPOC provides therapeutic benefits to LPN patients, at least on a short-term basis, by alleviating renal ischemic/reperfusion injury.

Clinical Trial Registration: Chinese Clinical Trial Registry, identifier [ChiCTR-TRC-14004766].

Dexmedetomidine reduces enteric glial cell injury induced by intestinal ischaemia-reperfusion injury through mitochondrial localization of TERT

This study was performed to uncover the effects of dexmedetomidine on oxidative stress injury induced by mitochondrial localization of telomerase reverse transcriptase (TERT) in enteric glial cells (EGCs) following intestinal ischaemia-reperfusion injury (IRI) in rat models. Following establishment of intestinal IRI models by superior mesenteric artery occlusion in Wistar rats, the expression and distribution patterns of TERT were detected. The IRI rats were subsequently treated with low or high doses of dexmedetomidine, followed by detection of ROS, MDA and GSH levels. Calcein cobalt and rhodamine 123 staining were also carried out to detect mitochondrial permeability transition pore (MPTP) and the mitochondrial membrane potential (MMP), respectively. Moreover, oxidative injury of mtDNA was determined, in addition to analyses of EGC viability and apoptosis. Intestinal tissues and mitochondria of EGCs were badly damaged in the intestinal IRI group. In addition, there was a reduction in mitochondrial localization of TERT, oxidative stress, whilst apoptosis of EGCs was increased and proliferation was decreased. On the other hand, administration of dexmedetomidine was associated with promotion of mitochondrial localization of TERT, whilst oxidative stress, MPTP and mtDNA in EGCs, and EGC apoptosis were all inhibited, and the MMP and EGC viability were both increased. A positive correlation was observed between different doses of dexmedetomidine and protective effects. Collectively, our findings highlighted the antioxidative effects of dexmedetomidine on EGCs following intestinal IRI, as dexmedetomidine alleviated mitochondrial damage by enhancing the mitochondrial localization of TERT.

Stellate Ganglion Block Combined with Dexmedetomidine Protects Obese Rats from Lipopolysaccharide-Induced Acute Lung Injury

Objective

To investigate the effect and mechanism of combined stellate ganglion block (SGB) and dexmedetomidine (Dex) in obesity-related acute lung injury.

Methods

Thirty-six 4-week-old male Wistar rats were randomly divided into 6 groups, each with 6 rats: blank group (Control), high-fat diet group (HFD), high-fat + lipopolysaccharide (LPS)-induced acute lung injury group (HFD + LPS), SGB group, Dex group, and SGB + Dex group. H&E staining detected the pathological structure of rat lung tissue. TUNEL staining was used to examine cell apoptosis in lung tissue. Oxidative factors were accessed by biochemical reagents. ELISA was employed to measure the levels of TNF-α, IL-1β, and MCP1 in rat alveolar lavage fluid. Western blot detected the protein expression of glucose-regulated Protein 78 (GRP78), C/EBP homologous protein (CHOP), protein kinase R-like endoplasmic reticulum kinase (PERK), and p-PERK in lung tissue.

Results

The body weight of rats in the HFD group was higher than that in the control group. The use of SGB or Dex alone could significantly reduce the rate of pulmonary edema and lung cell apoptosis in HFD-induced obese rats and reduce MPO, TNF-α, IL-1β, and MCP1 levels, increasing the activity of SOD and GSH-Px. In addition, using SGB or Dex alone can also significantly reduce the protein expression levels of GRP78, CHOP, and p-PERK. The combined use of SGB and Dex can enhance the above effects.

Conclusion

The combined use of SGB and Dex can protect against obesity-related acute lung injury and is more effective than using SGB or Dex alone.

Renoprotective Effect of Intraoperative Dexmedetomidine in Renal Transplantation

BACKGROUND

Renal dysfunction after kidney transplantation may be influenced by many reasons. This study was designed to evaluate whether the administration of dexmedetomidine (Dex) could ameliorate renal function and prognosis after kidney transplantation.

METHODS

A total of 65 patients were divided into Dex group (n = 33) and Con group (Con, n = 32). Dex group intravenously received an initial loading dose of 0.6 μg/kg Dex for 15 min before anaesthesia induction, followed by a rate of 0.4 μg/kg/h until 30 min after kidney reperfusion. By contrast, Con group received saline. The concentration of urinary kidney injury molecule-1 (KIM-1), serum creatinine (Cr), blood urea, urine output, β2 microglobulin (β2-MG), Cystatin C (CysC), and estimated glomerular filtration rate (eGFR) was recorded and compared between two groups during the course of the hospitalization or follow-up. Mean arterial pressure (MAP) and heart rate (HR), vasoactive drugs, and anaesthetics were recorded during the operation. Pain degree was evaluated using a visual analogue scale (VAS) after operation. Delayed graft function (DGF), graft loss, length of hospital stay, and mortality were compared between groups.

RESULTS

The concentration of KIM-1 in Dex group was lower than Con group at 2 h (P = 0.018), 24 h (P = 0.013), 48 h (P < 0.01), and 72 h (P < 0.01) after reperfusion. MAP of Dex group after tracheal intubation (P = 0.012) and incision (P = 0.018) and HR after intubation (P = 0.021) were lower than that of Con group. The dosage of sufentanil during operation in Dex group was less than Con group (P = 0.039). Patients that used atropine in Dex group were more than Con group (P = 0.027). Patients who received Dex presented with lower VAS scores at 6 h (P = 0.01) and 12 h (P = 0.002) after operation. Concentration of serum Cr and blood urea had no significant differences between groups before operation and on postoperative day 1 to 6. Urine output was recorded for 6 days after operation and had no differences between groups. Also, no differences were identified between two groups in urea, Cr, β2-MG, CysC, and eGFR in the first 3 months after operation. Incidence of DGF after operation was detected no difference between groups, while length of hospital stay in Dex group was less than Con group (P = 0.012).

CONCLUSION

Dex can decrease kidney injury marker level, attenuate perioperative stress, relieve the dosage of sufentanil and postoperative pain, and reduce length of hospital stay. However, Dex is not associated with changes in prognosis in the first 3 months after transplantation.

Intestinal ischemic reperfusion injury: Recommended rats model and comprehensive review for protective strategies

Intestinal ischemic reperfusion injury (IIRI) is a life-threatening condition with high morbidity and mortality in the clinic. IIRI was induced by intestinal ischemic diseases such as, small bowel transplantation, aortic aneurysm surgery, and strangulated hernias. Although related mechanisms have not been fully elucidated, during the last decade, researches have demonstrated that many factors are crucial in the pathological process, including oxidative stress (OS), epithelial barrier function disorder, and so on. Rats model, as the most applied animal IIRI model, provides specific targets for researches and therapeutic strategies. Moreover, various treatment strategies such as, anti-oxidative stress, anti-apoptosis, and anti-inflammation, have shown promising effects in alleviating IIRI. However, current researches cannot solve the clinical problems of IIRI, and specific treatment strategies are still needed to be exploited. This review focuses on a recommended experimental IIRI rat model and understanding of the involved mechanisms such as, OS, gut bacteria translocation, apoptosis, and necroptosis, aim at providing novel ideas for therapeutic strategies of IIRI.

Dexmedetomidine Resists Intestinal Ischemia-Reperfusion Injury by Inhibiting TLR4/MyD88/NF-κB Signaling

BACKGROUND

Intestinal ischemia/reperfusion (I/R) is a common clinical problem that occurs during various clinical pathological processes. Dexmedetomidine (DEX), a widely used anesthetic adjuvant agent, can induce protection against intestinal I/R in vivo; however, the underlying mechanism is not fully understood. In the present study, we aimed to investigate the protective effects of DEX and examine whether its mechanism was associated with the TLR4/MyD88/NF-κB signaling pathway.

METHODS

Sprague-Dawley rats were pretreated with DEX and then subjected to I/R-induced intestinal injury. In vivo, intestinal histopathological examination and scoring were performed, the levels of serum intestinal fatty acid-binding protein (I-FABP), intestinal tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and expression levels of TLR4, MyD88, and NF-κB in the intestine were determined. In in vitro experiments, the human colon carcinoma cell line (Caco-2) was incubated with DEX before deprivation/reoxygenation (OGD/R) treatment. The cell viability of Caco-2 cells, the levels of lactate dehydrogenase (LDH), TNF-α, and IL-1β in the supernatant, as well as protein expression of TLR4, MyD88, and NF-κB in Caco-2 cells, were measured. Statistical analysis was performed using SPSS version 21.0.

RESULTS

DEX preconditioning significantly reduced the intestinal pathological Chiu's score, serum I-FABP, intestinal TNF-α, IL-1β levels, and the protein expression of TLR4, MyD88, and NF-κB in the rats with intestinal I/R injury. Similarly, in vitro, DEX pretreatment protected against OGD/R-induced Caco-2 cell damage and inhibited TLR4/MyD88/NF-κB signaling, as evidenced by increased cell viability, decreased LDH activity, reduced TNF-α and IL-1β levels, as well as downregulated TLR4, MyD88, and NF-κB protein levels.

CONCLUSIONS

Our findings suggested that DEX could reduce intestinal I/R injury in rats and OGD/R damage in Caco-2 cells, and this protection might be attributed to antiinflammatory effects and inhibition of the TLR4/MyD88/NF-κB signaling pathway.

Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses

BACKGROUND

Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia.

OBJECTIVES

To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse.

STUDY DESIGN

Randomised, controlled, experimental study.

METHODS

Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests.

RESULTS

In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group.

MAIN LIMITATIONS

Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions.

CONCLUSIONS

Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.

MiR-23a-5p exacerbates intestinal ischemia-reperfusion injury by promoting oxidative stress via targeting PPAR alpha

MiR-23a-5p is involved in the occurrence and development of some serious diseases, but its effects on intestinal ischemia-reperfusion (II/R) injury is unclear. In this research, the hypoxia/reoxygenation (H/R) model on IEC-6 cells and II/R model in mice were used. The data showed that the ROS level in model group was significantly increased compared with control group. The level of intestinal MPO was increased and serum SOD was decreased in mice compared with sham group. Moreover, the expression levels of miR-23a-5p in model groups were obviously increased in vitro and in vivo, while the expression levels of PPARα, FOXO3α, PGC-1α, Nrf2, CAT, NQO1, HO-1 and SOD2 were significantly decreased. The double luciferase reporter gene assay showed that there was binding site between miR-23a-5p and PPARα. When miR-23a-5p was inhibited or PPARα gene was overexpressed, H/R-caused cell damage was alleviated and ROS level was decreased compared with NC group. PPARα expression level was increased, accompanied by the increased levels of FOXO3α, PGC-1α, Nrf2, CAT, NQO1, HO-1 and SOD2. After enhancing miR-23a-5p expression or silencing PPARα gene, H/R-caused cell damage was further aggravated compared with NC group, and ROS level was increased associated with the decreased levels of FOXO3α, PGC-1α, Nrf2, CAT, NQO1, HO-1 and SOD2. Our study demonstrated that miR-23a-5p exacerbated II/R injury by promoting oxidative stress via targeting PPARα, which should be considered as one new drug target to treat II/R injury.

Population analysis to assess the influence of age and body weight on pharmacokinetics and pharmacodynamics of dexmedetomidine in New Zealand White rabbits

The purpose of this work was i) to develop a population pharmacokinetic (PK) and pharmacodynamic (PD) model of dexmedetomidine (DEX) in New Zealand White rabbits, ii) to investigate the influence of the age and weight of the animals on the model parameters, and iii) to assess the linearity of DEX PKs in the examined dose range. This was a prospective, crossover study, using a total of 18 New Zealand White rabbits. DEX was administered as a single intravenous bolus injection in the doses from 25 to 300 μg kg^-1 . Each New Zealand White rabbit was given the same dose of drug in its three developmental stages. To determine the DEX PK, seven blood samples were taken from each animal. The pedal withdrawal reflex was the PD response used to assess the degree of sedation. Nonlinear mixed effects modelling was used for the population PK/PD analysis. The typical value of elimination clearance was 0.061 L min^-1 and was 35% higher in younger New Zealand White rabbits compared with older animals. The PK of DEX was linear in the examined concentration range. Age-related changes in sensitivity to DEX were not detected. The results suggest that due to the pharmacokinetics, younger animals will have lower DEX concentrations and a shorter duration of sedation than older animals given the same doses of DEX per kg of body weight.

Preconditioning with lidocaine and xylazine in experimental equine jejunal ischaemia

BACKGROUND

Pharmacological preconditioning of dexmedetomidine on small intestinal ischaemia/reperfusion injury has been reported in different animal models including horses.

OBJECTIVES

The objective was to assess if xylazine and lidocaine have a preconditioning effect in an experimental model of equine jejunal ischaemia.

STUDY DESIGN

Terminal in vivo experiment.

METHODS

Ten horses under general anaesthesia were either preconditioned with xylazine (group X; n = 5) or lidocaine (group L; n = 5). A historical untreated control group (group C; n = 5) was used for comparison. An established experimental model of equine jejunal ischaemia was applied, and intestinal samples were taken pre-ischaemia, after ischaemia and following reperfusion. Histomorphological examination was performed based on a modified Chiu score. Immunohistochemical staining for cleaved caspase-3, TUNEL and calprotectin was performed, and positive cell counts were expressed in cells/mm² .

RESULTS

There was no progression of histomorphological mucosal injury from ischaemia to reperfusion, and there were no differences in histomorphology between the groups. After ischaemia, group X had significantly less caspase-positive cells compared to the control group with a median difference of 227% (P = .01). After reperfusion, group X exhibited significantly lower calprotectin-positive cell counts compared to the control group, with a median difference of 6.8 cells/mm² in the mucosa and 44 cells in the serosa (P = .02 and .05 respectively). All groups showed an increase in caspase- and calprotectin-positive cells during reperfusion (P < .05). TUNEL-positive cells increased during ischaemia, followed by a decrease after reperfusion (P < .05).

MAIN LIMITATIONS

The small sample size and the use of a historical control group. Preconditioning effects of the tested drugs may be masked by the protective effects of isoflurane in the anaesthetic protocol.

CONCLUSIONS

Preconditioning with lidocaine did not have any effect on the tested variables. The lower cell counts of caspase- and calprotectin-positive cells in group X may indicate a beneficial effect of xylazine on ischaemia/reperfusion injury. Due to the absence of a concurrent reduction of histomorphological injury, the clinical significance remains uncertain.

Low-Dose Dexmedetomidine Accelerates Gastrointestinal Function Recovery in Patients Undergoing Lumbar Spinal Fusion

Background: Dexmedetomidine possesses sedative, sympatholytic, and opioid-sparing properties, but its impact on postoperative gastrointestinal function is controversial. Methods: This single-center, prospective, randomized study compared low-dose dexmedetomidine and placebo on gastrointestinal function recovery and inflammation after posterior lumbar spinal fusion. Sixty-six patients were randomized into two groups and received normal saline (control group) or dexmedetomidine (DEX group) during posterior lumbar fusion. Blood was taken at five timepoints to measure lipopolysaccharides, tumor necrosis factor-α, and C-reactive protein. The primary outcome was duration to first flatus. The secondary outcomes were inflammatory mediators and determination of correlations between perioperative factors and duration to first flatus. Results: Patients in DEX group showed significantly lower duration to first flatus (15.37 [13.35-17.38] vs 19.58 [17.31-21.86] h; p = 0.006) and overall sufentanil consumption (67.19 [63.78-70.62] vs 74.67 [69.96-79.30] μg; p = 0.011) than controls. Lipopolysaccharides, tumor necrosis factor-α, and C-reactive protein did not differ between the groups at any timepoint (all p > 0.05). Multiple linear regression modeling assessed the ability of independent variables to predict variance in duration to first flatus (adjusted R² = 0.379, p = 0.000). In the model, age (β = 0.243, p = 0.003), gender (β = -3.718, p = 0.011), BMI (β = -0.913, p = 0.001), operative segments (β = -4.079, p = 0.028), and overall sufentanil consumption (β = 0.426, p = 0.000) contributed significantly. Conclusions: Thus, low-dose dexmedetomidine accelerates gastrointestinal function recovery after lumbar spinal fusion. The effect may be partially produced by opioid-sparing effects rather than inhibition of inflammation. Clinical Trial Registration: www.chictr.org.cn, identifier ChiCTR1800018127.

Irisin Contributes to the Hepatoprotection of Dexmedetomidine during Intestinal Ischemia/Reperfusion

Intestinal ischemia/reperfusion (I/R), which is associated with high morbidity and mortality, is also accompanied with abnormal energy metabolism and liver injury. Irisin, a novel exercise-induced hormone, can regulate adipose browning and thermogenesis. The following study investigated the potential role of dexmedetomidine in liver injury during intestinal I/R in rats. Adult male Sprague-Dawley rats underwent occlusion of the superior mesenteric artery for 90 min followed by 2 h of reperfusion. Dexmedetomidine or irisin-neutralizing antibody was intravenously administered for 1 h before surgery. The results demonstrated that severe intestine and liver injuries occurred during intestinal I/R as evidenced by pathological scores and an apparent increase in serum diamine oxidase (DAO), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels. In addition, the hepatic irisin, cleaved caspase-3, Bax, and NLRP3 inflammasome components (including NLRP3, ASC, and caspase-1), protein expressions, apoptotic index, reactive oxygen species (ROS), malondialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor- (TNF-) α, and interleukin- (IL-) 6 levels increased; however, the serum irisin level and hepatic Bcl-2 protein expression and superoxide dismutase (SOD) activity decreased after intestinal I/R. Interestingly, dexmedetomidine could reduce the above listed changes and increase the irisin levels in plasma and the liver in I/R rats. Dexmedetomidine-mediated protective effects on liver injury and NLRP3 inflammasome activation during intestinal I/R were partially abrogated via irisin-neutralizing antibody treatment. The results suggest that irisin might contribute to the hepatoprotection of dexmedetomidine during intestinal ischemia/reperfusion.

Dexmedetomidine Attenuates Myocardial Ischemia-Reperfusion Injury in Diabetes Mellitus by Inhibiting Endoplasmic Reticulum Stress

OBJECTIVE

With the increasing incidence of diabetes mellitus (DM) combined with myocardial ischemia, how to reduce myocardial ischemia-reperfusion injury in DM patients has become a major problem faced by clinicians. We investigated the therapeutic effects of dexmedetomidine (DEX) on myocardial ischemia-reperfusion injury in DM rats and its effect on endoplasmic reticulum stress.

METHODS

SD rats with SPF grade were randomly divided into 6 groups: non-DM rats were divided into the sham operation group (NDM-S group), ischemia-reperfusion group (NDM-IR group), and dexmedetomidine group (NDM-DEX group); DM rats were divided into the diabetic sham operation group (DM-S group), diabetes-reperfusion group (DM-IR group), and diabetes-dexmedetomidine (DM-DEX) group, with 10 rats in each group. Then the effects of DEX on the changes of CK-MB and cTnT levels were examined. The effects of myocardial pathological damage and myocardial infarct size were detected. The apoptosis of cardiomyocytes was detected. The apoptosis of heart tissue cells was also tested through the expressions of cleaved caspase-3, Bcl-2, and Bax proteins. The expression of endoplasmic reticulum stress-related proteins GRP78, CHOP, ERO1α, ERO1β, and PDI was examined. The hypoxia/reoxygenation (H/R) injury cell model was established, the effects of DEX, DEX+ ERS agonist on cell apoptosis was also detected.

RESULTS

The myocardial damage of DM-IR was more severe than that of NDM-IR rats. DEX could reduce the expression of CK-MB and cTnT, reduce pathological damage, and reduce scar formation and improve fibrosis. DEX can reduce the expression of GRP78, CHOP, ERO1α, ERO1β, and PDI proteins in vivo and in vitro. And the effect of DEX on cell apoptosis could be blocked by ERS agonist.

CONCLUSION

DEX attenuates myocardial ischemia-reperfusion injury in DM rats and H/R injury cell, which is associated with the reduction of ERS-induced cardiomyocyte apoptosis.

Effects of dexmedetomidine on H-FABP, CK-MB, cTnI levels, neurological function and near-term prognosis in patients undergoing heart valve replacement

This study investigated the effects of dexmedetomidine on heart-type fatty acid binding protein (H-FABP), creatine kinase isoenzymes (CK-MB), and troponin I (cTnI) levels, neurological function and near-term prognosis in patients undergoing heart valve replacement. Patients undergoing heart valve replacement were randomly allocated to remifentanil anesthesia (control group, n=48) or dexmedetomidine anesthesia (observation group, n=48). Hemodynamic parameters were measured before anesthesia induction (T1), 1 min after intubation (T2), 10 min after start of surgery (T3), and on completion of surgery (T4). Levels of plasma H-FABP, CK-MB and cTnI were measured 10 min before anesthesia induction (C1), 10 min after start of surgery (C2), on completion of surgery (C3), 6 h after surgery (C4), and 24 h after surgery (C5). S100β protein and serum neuron-specific enolase (NSE) were detected 10 min before anesthesia induction (C1), and 24 h after surgery (C5). Neurological and cardiac function was evaluated 24 h after surgery. Incidence of cardiovascular adverse events was recorded for 1 year of follow-up. There were no significant differences in the average heart rate between the two groups during the perioperative period. The mean arterial pressure in the observation group was significantly lower than control group (P<0.05). Levels of H-FABP, CK-MB and cTnI at C2, C3, C4 and C5, were significantly higher than C1, but significantly lower in the observation versus control group (P<0.05). Twenty-four hours after surgery, levels of S100β and NSE in both groups were higher than those before induction (P<0.05), but significantly lower in the observation versus control group (P<0.05). Twenty-four hours after surgery, neurological function scores were better, and myocardial contractility and arrhythmia scores significantly lower in the observation versus control group (P<0.05 for all). After follow-up for 1 year, incidence of cardiovascular adverse events was significantly lower in the observation versus control group (P<0.05). Dexmedetomidine anesthesia can effectively maintain hemodynamic stability, reduce myocardial injury and the occurrence of cognitive dysfunction, and improve prognosis in patients undergoing heart valve replacement.

The effects of dexmedetomidine preconditioning on aged rat heart of ischaemia reperfusion injury

To assess the effect of dexmedetomidine on myocardial ischemia reperfusion injury in vivo aged rat heart. 40 healthy male, 20month aged, 350-400g Sprague-Dawley rats. Rats were divided into four groups randomly(n=10): group of ischemic preconditioning(IP group), group of Sham(CS group), group of dexmedetomidine(DP group), Ischemia-reperfusion injury group(IR group). The date of HR and ±dp/dtmax were detected before and after the occur of ischemia reperfusion. Superoxide dismutase (SOD) and malondialdehyde (MDA) activity were recorded; myocardial infarct size was calculated at the end of reperfusion. HR in each group decreased after thoracotomy. Compared with CS group, the HR in IR group reduced significantly (P<0.05). After given dexmedetomidine, HR in the DP group began to decrease significantly. Left heart function in IR group compared with the CS group showed that a statistically reduce of left ventricular function happened in IR group. ±dp/dtmax of the IR groups compared with the CS group were increased. SOD activity reduced and MDA in myocardial tissue homogenates increased in IR group (P<0.05); SOD activity in DP group compared with IR group deduced, MDA increased (P<0.05). Dexmedetomidine preconditioning can effectively reduce ischemia reperfusion injury of the aged rat in vivo, have a protective effect on aged rat heart.

Does remifentanil attenuate renal ischemia-reperfusion injury better than dexmedetomidine in rat kidney?

Background

Ischemia–reperfusion (I/R) injury is a common cause of patient morbidity and mortality in the perioperative period. Patients undergoing long-lasting, abdominal, and urogenital surgeries with risk factors such as advanced age, peripheral artery disease, diabetes mellitus, renovascular disease, and congestive heart failure are candidates for acute kidney injury (AKI) due to impaired renal perfusion and decreased functional renal reserve. Pharmacological agents with multiple functions and anti-oxidative and anti-inflammation properties may be promising preventative strategies for AKI. Recently, dexmedetomidine (dex) has been postulated to have renoprotective effects.

Objectives

We aimed to investigate the protective effects of an intravenous anesthetic remifentanil in renal I/R injury in the rat in comparison with dex.

Materials and methods

A total of 30 Sprague Dawley adult rats were randomly assigned into five groups: the control group (group C, n=6), the sham group (group Sh, n=6, saline-infused rats without I/R injury), the saline group (group S, n=6, saline-infused rats with I/R injury), the remifentanil-treated group (group REM, n=6), and the dexmedetomidine-treated group (group DEX, n=6). The infusions (saline, remifentanil, and dex) were started after anesthesia induction and right nephrectomy and continued until the end of the surgical procedure. In I/R injury groups, the left renal artery and vein were occluded together by a clamp for 30 minutes and reperfusion lasted for 30 minutes. The rats were sacrificed after reperfusion, and the left kidney tissue was harvested. Blood samples were drawn from all animals to evaluate plasma neutrophil gelatinase-associated lipocalin (NGAL) at the beginning, 15 minutes after ischemia, 15 minutes after reperfusion, and 6 hours after the surgical procedure (T0, T1, T2, and T3, respectively).

Results

The plasma NGAL levels exhibited increase at T1, T2, and T3 compared to the levels at T0 in group S (P<0.05). In group REM, there was a significant increase in plasma NGAL levels at T3 in comparison to those at T0, T1, and T2. The plasma NGAL levels at T2 in group S were significantly higher than those at T2 in group DEX (P<0.05). The groups S and REM showed significantly higher plasma NGAL levels at T3 compared to those at T0 (P<0.05). Upon histological examination, there was no difference among the study groups when left kidneys were evaluated (P>0.05).

Conclusion

The NGAL levels and histopathological findings reflected protection by dex against renal I/R injury. However, the same exact results could not be mentioned for remifentanil depending on our study results.

Two Phase Modulation of [Formula: see text] Entry and Cl-/[Formula: see text] Exchanger in Submandibular Glands Cells by Dexmedetomidine

Dexmedetomidine (Dex), a highly selective α2-adrenoceptor agonist, attenuates inflammatory responses induced by lipopolysaccharide (LPS) and induces sedative and analgesic effects. Administration of Dex also reduces salivary secretion in human subjects and inhibits osmotic water permeability in rat cortical collecting ducts. However, little is known about the mechanisms underlying the effects of Dex on salivary glands fluid secretion. We demonstrated the α2-adrenoceptor expression in the basolateral membrane of mouse submandibular glands (SMG). To investigate fluid secretion upon treatment with Dex, we studied the effects of Dex on the activity of Na+-K+-2Cl- cotransporter1 (NKCC1) and Cl-/[Formula: see text] exchange (CBE), and on downstream pro-inflammatory cytokine expression in isolated primary mouse SMG cells. Dex acutely increased CBE activity and NKCC1-mediated and independent [Formula: see text] entry in SMG duct cells, and enhanced ductal fluid secretion in a sealed duct system. Dex showed differential effects on cholinergic/adrenergic stimulations and inflammatory mediators, histamine, and LPS, stimulations-induced Ca2+ in mouse SMG cells. Both, histamine- and LPS-induced intracellular Ca2+ increases were inhibited by Dex, whereas carbachol-stimulated Ca2+ signals were not. Long-lasting (2 h) treatment with Dex reduced CBE activity in SMG and in human submandibular glands (HSG) cells. Moreover, when isolated SMG cells were stimulated with Dex for 2 h, phosphodiesterase 4D (PDE4D) expression was enhanced. These results confirm the anti-inflammatory properties of Dex on LPS-mediated signaling. Further, Dex also inhibited mRNA expression of interleukin-6 and NADPH oxidase 4. The present study also showed that α2-adrenoceptor activation by Dex reduces salivary glands fluid secretion by increasing PDE4D expression, and subsequently reducing the concentration of cAMP. These findings reveal an interaction between the α2-adrenoceptor and PDE4D, which should be considered when using α2-adrenoceptor agonists as sedative or analgesics.

The Preventive Effect of Dexmedetomidine Against Postoperative Intra-abdominal Adhesions in Rats

This study aimed to determine the possible preventive effects of dexmedetomidine on postoperative intra-abdominal adhesions. Dexmedetomidine is a highly selective and potent α2 adrenergic agonist with sedative, analgesic, anxiolytic, sympatholytic, hemodynamic, and diuretic properties. In recent years, investigations have shown that dexmedetomidine possesses secondary antioxidant and also anti-inflammatory effects. Thirty Wistar albino male rats were randomized and divided into 3 groups of 10 animals each: group 1, sham-operated; group 2, cecal abrasion + peritoneal dissection; group 3, cecal abrasion + peritoneal dissection followed by daily intravenous injection of 10 μg/kg dexmedetomidine for 10 days. The animals were killed on postoperative day 21. Blood and cecal samples were taken for biochemical and histopathologic evaluation. In this study, biochemical and pathologic parameters were significantly better in the cecal abrasion + peritoneal dissection + dexmedetomidine group when compared with the cecal abrasion + peritoneal dissection group. Tissue malondialdehyde, myeloperoxidase, total sulfhydryl, and catalase were found to be significantly different between the cecal abrasion/peritoneal dissection + dexmedetomidine and the cecal abrasion/peritoneal dissection groups. Plasma malondialdehyde and total sulfhydryl values were also statistically different between these groups (P < 0.05). Statistical analyses of mean pathologic scores showed that the histopathologic damage in the cecal abrasion/peritoneal dissection + dexmedetomidine group was significantly less than the damage in the control group (P < 0.05 for all pathologic parameters). The results of this study show that dexmedetomidine had a significant preventive effect on postoperative intra-abdominal adhesions. We concluded that these effects might be due to antioxidant and anti-inflammatory activities.

Dexmedetomidine improves gastrointestinal motility after laparoscopic resection of colorectal cancer: A randomized clinical trial

BACKGROUND

To investigate the effects of intraoperative application of dexmedetomidine (Dex) on early gastrointestinal motility after laparoscopic resection of colorectal cancer.

METHODS

In this prospective, randomized double-blind investigation, 60 patients who underwent laparoscopic resection of colorectal cancer were randomly allocated to receive Dex (DEX group, n = 30) or saline (CON group, n = 30). In the DEX group, Dex was loaded (1 μg/kg) before anesthesia induction and was infused (0.3 μg/kg/h) during surgery. Time to postoperative first flatus (FFL) and first feces (FFE), and time to regular diet were recorded. Serum diamine oxidase (DAO) activity and intestinal fatty acid-binding protein (I-FABP) were detected.

RESULTS

Both the time to the FFL (44.41 ± 4.51 hours vs 61.03 ± 5.16 hours, P = 0.02) and the time to the FFE (60.67 ± 4.94 hours vs 82.50 ± 6.88 hours, P = 0.014) were significantly shorter in the DEX group than the CON group. Furthermore, the time to regular diet of the DEX group was shorter than that of the CON group (76.15 ± 4.11 hours vs 91.50 ± 5.70 hours, P = 0.037). Both DAO and I-FABP increased significantly from beginning of surgery to postoperative day 1 in the CON group (2.49 ± 0.41 ng/mL vs 4.48 ± 0.94 ng/mL for DAO, P = 0.028, 1.32 ± 0.09 ng/mL vs 2.17 ± 0.12 ng/mL for I-FABP, P = 0.045, respectively), whereas no significant change was observed in the DEX group. Furthermore, patients in the DEX group had stable hemodynamics and shorter hospital stay than those in the CON group.

CONCLUSION

Dex administration intraoperatively benefits recovery of gastrointestinal motility function after laparoscopic resection of colorectal cancer with stable hemodynamics during surgery though further studies are needed to explore the mechanisms of Dex on gastrointestinal motility.

Effectiveness of sugammadex for cerebral ischemia/reperfusion injury

Cerebral ischemia may cause permanent brain damage and behavioral dysfunction. The efficacy and mechanisms of pharmacological treatments administered immediately after cerebral damage are not fully known. Sugammadex is a licensed medication. As other cyclodextrins have not passed the necessary phase tests, trade preparations are not available, whereas sugammadex is frequently used in clinical anesthetic practice. Previous studies have not clearly described the effects of the cyclodextrin family on cerebral ischemia/reperfusion (I/R) damage. The aim of this study was to determine whether sugammadex had a neuroprotective effect against transient global cerebral ischemia. Animals were assigned to control, sham-operated, S 16 and S 100 groups. Transient global cerebral ischemia was induced by 10-minute occlusion of the bilateral common carotid artery, followed by 24-hour reperfusion. At the end of the experiment, neurological behavior scoring was performed on the rats, followed by evaluation of histomorphological and biochemical measurements. Sugammadex 16 mg/kg and 100 mg/kg improved neurological outcome, which was associated with reductions in both histological and neurological scores. The hippocampus TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase results in the S 16 and S 100 treatment groups were significantly lower than those of the I/R group. Neurological scores in the treated groups were significantly higher than those of the I/R group. The study showed that treatment with 16 mg/kg and 100 mg/kg sugammadex had a neuroprotective effect in a transient global cerebral I/R rat model. However, 100 mg/kg sugammadex was more neuroprotective in rats.

Curcumin and dexmedetomidine prevents oxidative stress and renal injury in hind limb ischemia/reperfusion injury in a rat model

Curcumin and dexmedetomidine have been shown to have protective effects in ischemia-reperfusion injury on various organs. However, their protective effects on kidney tissue against ischemia-reperfusion injury remain unclear. We aimed to determine whether curcumin or dexmedetomidine prevents renal tissue from injury that was induced by hind limb ischemia-reperfusion in rats. Fifty rats were divided into five groups: sham, control, curcumin (CUR) group (200 mg/kg curcumin, n = 10), dexmedetomidine (DEX) group (25 μg/kg dexmedetomidine, n = 10), and curcumin-dexmedetomidine (CUR-DEX) group (200 mg/kg curcumin and 25 μg/kg dexmedetomidine). Curcumin and dexmedetomidine were administered intraperitoneally immediately after the end of 4 h ischemia, just 5 min before reperfusion. The extremity re-perfused for 2 h and then blood samples were taken and total antioxidant capacity (TAC), total oxidative status (TOS) levels, and oxidative stress index (OSI) were measured, and renal tissue samples were histopathologically examined. The TAC activity levels in blood samples were significantly lower in the control than the other groups (p < 0.01 for all comparisons). The TOS activity levels in blood samples were significantly higher in Control group and than the other groups (p <  0.01 for all comparison). The OSI were found to be significantly increased in the control group compared to others groups (p < 0.001 for all comparisons). Histopathological examination revealed less severe lesions in the sham, CUR, DEX, and CUR-DEX groups, compared with the control group (p < 0.01). Rat hind limb ischemia-reperfusion causes histopathological changes in the kidneys. Curcumin and dexmedetomidine administered intraperitoneally was effective in reducing oxidative stress and renal histopathologic injury in an acute hind limb I/R rat model.

Protection against ischemia/reperfusion‑induced renal injury by co‑treatment with erythropoietin and sodium selenite

Ischemia/reperfusion injury (IRI) has lzong been an area of concern and focus of investigations. Erythropoietin (EPO) exhibits multiple protective effects, and selenium is an antioxidant trace element in the body, however, there have been no reports concerning the effects of EPO combined with sodium selenite on IRI. In the present study, a mouse model of renal IRI (RIRI) was pre–treated with EPO and sodium selenite to determine the most appropriate combination ratio of the two for further investigation. The results revealed that EPO and sodium selenite had synergistic protective effects in RIRI. EPO was identified as the predominant treatment component, with sodium selenite serving as an adjuvant, and combination treatment was markedly more effective, compared with treatment with either drug alone. The optimal ratio of treatment was 10:1 (10 IU EPO: 1 µg sodium selenite). The results indicated that RIRI markedly induced renal injury, as evidenced by elevated levels of blood urea nitrogen (BUN), as well as higher pathological scores, based on hematoxylin and eosin staining. Pre–treatment with EPO and sodium selenite significantly decreased serum expression levels of BUN and malonaldehyde, and increased the expression levels of superoxide dismutase, glutathione peroxidase and nitric oxide (NO), compared with the model group. Furthermore, co treatment with EPO and sodium selenite upregulated the protein expression levels of phosphatidylinositol 3 kinase (PI3K) in renal tissue samples. Together, the results suggested that co administration of EPO and sodium selenite effectively ameliorates IRI induced renal injury by reducing oxidative stress and activating the PI3K/NO signaling pathway.

Monitoring dynamic alterations in calcium homeostasis by T1-mapping manganese-enhanced MRI (MEMRI) in the early stage of small intestinal ischemia-reperfusion injury

Manganese-enhanced MRI studies have proven to be useful in monitoring physiological activities associated with calcium ions (Ca(2+)) due to the paramagnetic property of the manganese ion (Mn(2+)), which makes it an excellent probe of Ca(2+) . In this study, we developed a method in which a Mn(2+)-enhanced T1 -map MRI could enable the monitoring of Ca(2+) influx during the early stages of intestinal ischemia-reperfusion (I/R) injury. The Mn(2+) infusion protocol was optimized by obtaining dose-dependent and time-course wash-out curves using a Mn(2+)-enhanced T1-map MRI of rabbit abdomens following an intravenous infusion of 50 mmol/l MnCl2 (5-10 nmol/g body weight (BW)). In the rabbit model of intestinal I/R injury, T1 values were derived from the T1 maps in the intestinal wall region and revealed a relationship between the dose of the infused MnCl2 and the intestinal wall relaxation time. Significant Mn(2+) clearance was also observed over time in control animals after the infusion of Mn(2+) at a dose of 10 nmol/g BW. This technique was also shown to be sensitive enough to monitor variations in calcium ion homeostasis in vivo after small intestinal I/R injury. The T1 values of the intestinal I/R group were significantly lower (P < 0.05) than that of the control group at 5, 10, and 15 min after Mn(2+) infusion. Our data suggest that MnCl2 has the potential to be an MRI contrast agent that can be effectively used to monitor changes in intracellular Ca(2+) homeostasis during the early stages of intestinal I/R injury.

Protective effects of dexmedetomidine on intestinal ischemia-reperfusion injury

Dexmedetomidine (DEX) has been hypothesized to possess anti-oxidative properties that may mitigate the damage caused by ischemia-reperfusion (IR) injury. The aim of the present study was to examine the effects of DEX on intestinal contractile activity, inflammation and apoptosis following intestinal IR injury. Intestinal IR injury was induced in rats by complete occlusion of the superior mesenteric artery for 60 min, followed by a 60-min reperfusion period. Rats received an intraperitoneal injection of 25 µg/kg DEX at 30 min prior to the mesenteric IR injury. Following reperfusion, segments of the terminal ileum were rapidly extracted and transferred into an isolated organ bath. The contractile responses to receptor-mediated acetylcholine (Ach) and non-receptor-mediated potassium chloride (KCl) were subsequently examined. Nitric oxide (NO) levels were determined and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, Bax and Bcl-2 were measured using an enzyme-linked immunosorbent assay. The levels of telomerase and caspase-3 were determined using reverse transcription-quantitative polymerase chain reaction. The results indicated that DEX treatment produced a significant reduction in the IR-induced contractile response to Ach and KCl in the intestinal tissue. Furthermore, DEX appeared to significantly ameliorate intestinal IR injury, in addition to reducing the production of NO. Similar reductions were observed in the intestinal expression levels of TNF-α and IL-6. In addition, DEX treatment resulted in a reduction in the expression levels of Bax in the intestinal tissues, while increasing those of Bcl-2, in addition to significantly increasing the mRNA levels of telomerase and caspase-3. Therefore, the present study indicated that NO, TNF-α and IL-6 may partially contribute to the pathogenesis of intestinal IR injury in addition to the increased expression levels of Bax, Bcl-2, telomerase and caspase-3. These findings suggest that DEX possesses beneficial anti-apoptotic and anti-inflammatory effects in intestinal tissue following bowel injury.

Dexmedetomidine ameliorates nocifensive behavior in humanized sickle cell mice

Patients with sickle cell disease (SCD) can have recurrent episodes of vaso-occlusive crises, which are associated with severe pain. While opioids are the mainstay of analgesic therapy, in some patients, increasing opioid use results in continued and increasing pain. Many believe that this phenomenon results from opioid-induced tolerance or hyperalgesia or that SCD pain involves non-opioid-responsive mechanisms. Dexmedetomidine, a specific α2-adrenoreceptor agonist, which has sedative and analgesic properties, reduces opioid requirements, and can facilitate opioid withdrawal in clinical settings. We hypothesized that dexmedetomidine would ameliorate the nociception phenotype of SCD mice. Townes and BERK SCD mice, strains known to have altered nociception phenotypes, were used in a crossover preclinical trial that measured nocifensive behavior before and after treatment with dexmedetomidine or vehicle. In a linear dose-effect relationship, over 60-min, dexmedetomidine, compared with vehicle, significantly increased hot plate latency in Townes and BERK mice (P≤0.006). In sickle, but not control mice, dexmedetomidine improved grip force, an indicator of muscle pain (P=0.002). As expected, dexmedetomidine had a sedative effect in sickle and control mice as it decreased wakefulness scores compared with vehicle (all P<0.001). Interestingly, the effects of dexmedetomidine on hot plate latency and wakefulness scores were different in sickle and control mice, i.e., dexmedetomidine-related increases in hotplate latency and decreases in wakefulness scores were significantly smaller in Townes sickle compared to control mice. In conclusion, these findings of beneficial effects of dexmedetomidine on the nociception phenotype in SCD mice might support the conduct of studies of dexmedetomidine in SCD patients.

Bradycardia in perspective-not all reductions in heart rate need immediate intervention

According to Wikipedia, the word 'bradycardia' stems from the Greek βραδύς, bradys, 'slow', and καρδία, kardia, 'heart'. Thus, the meaning of bradycardia is slow heart rate but not necessarily too slow heart rate. If looking at top endurance athletes they may have a resting heart rate in the very low thirties without needing emergent intervention with anticholinergics, isoprenaline, epinephrine, chest compressions or the insertion of an emergency pacemaker (Figure 1). In fact, they withstand these episodes without incident, accommodating with a compensatory increase in stroke volume to preserve and maintain cardiac output. With this in mind, it is difficult for the authors to fully understand and agree with the general sentiment amongst many pediatric anesthesiologists that all isolated bradycardia portends impending doom and must be immediately treated with resuscitative measures.

Optimal doses of sevoflurane and propofol in rabbits

BACKGROUND

Although sevoflurane and propofol are commonly used anesthetics in rabbits, optimal doses of remain unclear. We thus assessed the optimal hypnotic doses of sevoflurane and propofol, and evaluated the influence of dexmedetomidine on sevoflurane and propofol requirements.

METHODS

Twenty-eight Japanese white rabbits were randomly assigned to one of four groups (n=7 each). Rabbits were given either sevoflurane, propofol, sevoflurane+dexmedetomidine, or propofol+dexmedetomidine (injected 30 μg∙kg(-1)∙hr(-1) for 10 min followed by an infusion of 3.5 μg∙kg(-1)∙hr(-1)). Hypnotic level was evaluated with Bispectral Index (BIS), a well-validated electroenchalographic measure, with values between 40 and 60 representing optimal hypnosis. BIS measurements were made 10 minutes after the adjustment of target end-tidal sevoflurane concentration in the sevoflurane group and sevoflurane+dexmedetomidine group, and at 10 min after the change of infusion rate in the propofol group and propofol+dexmedetomidine group.

RESULTS

BIS values were linearly related to sevoflurane concentration and propofol infusion rate, with or without dexmedetomidine. Sevoflurane concentration at BIS=50 was 3.9±0.2% in the sevoflurane group and 2.6±0.3% in the sevoflurane+dexmedetomidine group. The propofol infusion rate to make BIS=50 was 102±5 mg∙kg(-1)∙hr(-1) in the propofol group, and 90±10 mg∙kg(-1)∙hr(-1) in the propofol+dexmedetomidine group.

CONCLUSIONS

The optimal end-tidal concentration of sevoflurane alone was thus 3.9%, and optimal infusion rate for propofol alone was 102 mg∙kg(-1)∙hr(-1). Dexmedetomidine reduced sevoflurane requirement by 33% and propofol requirement by 11%.

The effect of colchicine and low-dose methotrexate on intestinal ischemia/reperfusion injury in an experimental model

AIM

Intestinal ischemia/reperfusion (I/R) injury is a serious clinical condition. Colchicine and low-dose methotrexate have anti-inflammatory features. An experimental model was conducted to investigate the effect of colchicine and methotrexate on intestinal I/R injury.

METHODS

Twenty-four rats were included. Only laparotomy was done in control group (CG, n=6). In experimental groups, superior mesenteric artery was occluded. After 1h ischemia, reperfusion (1h) was started by de-occlusion. 30min before reperfusion, saline in sham group (SG, n:6), colchicine (1mg/kg) in colchicine group (CNG, n:6), and methotrexate (0.1mg/kg) in methotrexate group (MTXG, n:6) were infused intraperitoneally. Small intestines were harvested for evaluation of intestinal mucosal injury (Chiu score) and oxidative stress markers (nitric oxide: NO, malondialdehyde: MDA, superoxide dismutase: SOD).

RESULTS

Biochemically, MDA levels were significantly low in CG compared to SG, CNG, and MTXG (p<0.05). NO levels were significantly low and SOD levels were significantly high in CG compared to MTXG (p<0.05). Histopathologically, Chiu score was significantly low in CG compared to SG, CNG, and MTXG (p<0.05), and significantly high in MTXG compared to SG and CNG (p<0.05).

CONCLUSION

The present experimental model caused I/R injury in rat intestines. Contrary to literature, it was found that methotrexate worsens and colchicine does not attenuate intestinal I/R injury.

Molecular targets and mechanism of action of dexmedetomidine in treatment of ischemia/reperfusion injury

Dexmedetomidine (DEX), a highly specific α2-adrenergic agonist, which exhibits anaesthetic-sparing, analgesia and sympatholytic properties. DEX modulates gene expression, channel activation, transmitter release, inflammatory processes and apoptotic and necrotic cell death. It has also been demonstrated to have protective effects in a variety of animal models of ischemia/reperfusion (I/R) injury, including the intestine, myocardial, renal, lung, cerebral and liver. The broad spectrum of biological activities associated with DEX continues to expand, and its diverse effects suggest that it may offer a novel therapeutic approach for the treatment of human diseases with I/R involvement.

Dexmedetomidine preconditioning ameliorates kidney ischemia-reperfusion injury

Kidney ischemia-reperfusion (I/R) injury is a common cause of acute kidney injury. We tested whether dexmedetomidine (Dex), an alpha2 adrenoceptor (α2-AR) agonist, protects against kidney I/R injury. Sprague-Dawley rats were divided into four groups: (1) Sham-operated group; (2) I/R group (40 min ischemia followed by 24 h reperfusion); (3) I/R group + Dex (1 μg/kg i.v. 60 min before the surgery), (4) I/R group + Dex (10 μg/kg). The effects of Dex postconditiong (Dex 1 or 10 μg/kg i.v. after reperfusion) as well as the effects of peripheral α2-AR agonism with fadolmidine were also examined. Hemodynamic effects were monitored, renal function measured, and acute tubular damage along with monocyte/macrophage infiltration scored. Kidney protein kinase B, toll like receptor 4, light chain 3B, p38 mitogen-activated protein kinase (p38 MAPK), sirtuin 1, adenosine monophosphate kinase (AMPK), and endothelial nitric oxide synthase (eNOS) expressions were measured, and kidney transciptome profiles analyzed. Dex preconditioning, but not postconditioning, attenuated I/R injury-induced renal dysfunction, acute tubular necrosis and inflammatory response. Neither pre- nor postconditioning with fadolmidine protected kidneys. Dex decreased blood pressure more than fadolmidine, ameliorated I/R-induced impairment of autophagy and increased renal p38 and eNOS expressions. Dex downregulated 245 and upregulated 61 genes representing 17 enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, in particular, integrin pathway and CD44. Ingenuity analysis revealed inhibition of Rac and nuclear factor (erythroid-derived 2)-like 2 pathways, whereas aryl hydrocarbon receptor (AHR) pathway was activated. Dex preconditioning ameliorates kidney I/R injury and inflammatory response, at least in part, through p38-CD44-pathway and possibly also through ischemic preconditioning.

Modulating the p66shc signaling pathway with protocatechuic acid protects the intestine from ischemia-reperfusion injury and alleviates secondary liver damage

Intestinal ischemia-reperfusion (I/R) injury is a serious clinical pathophysiological process that may result in acute local intestine and remote liver injury. Protocatechuic acid (PCA), which has been widely studied as a polyphenolic compound, induces expression of antioxidative genes that combat oxidative stress and cell apoptosis. In this study, we investigated the effect of PCA pretreatment for protecting intestinal I/R-induced local intestine and remote liver injury in mice. Intestinal I/R was established by superior mesenteric artery occlusion for 45 min followed by reperfusion for 90 min. After the reperfusion period, PCA pretreatment markedly alleviated intestine and liver injury induced by intestinal I/R as indicated by histological alterations, decreases in serological damage parameters and nuclear factor-kappa B and phospho-foxo3a protein expression levels, and increases in glutathione, glutathione peroxidase, manganese superoxide dismutase protein expression, and Bcl-xL protein expression in the intestine and liver. These parameters were accompanied by PCA-induced adaptor protein p66shc suppression. These results suggest that PCA has a significant protective effect in the intestine and liver following injury induced by intestinal I/R. The protective effect of PCA may be attributed to the suppression of p66shc and the regulation of p66shc-related antioxidative and antiapoptotic factors.

The effect of silymarin on mesenteric ischemia-reperfusion injury

OBJECTIVE

To examine the effect of silymarin (SM), a mixture of flavonoids and polyphenols extracted from Silybum marianum, on mesenteric ischemia-reperfusion (I-R) injury in a rat model.

MATERIALS AND METHODS

Fifty rats were randomly divided into 5 groups (n = 10). Group 1 was sham operated, while groups 2-5 were subjected to mesenteric I-R lasting 1 h. Group 2 received isotonic sodium chloride, group 3 received SM (100 mg/kg/day) for 7 days before I-R, group 4 received SM for 7 days after I-R, and group 5 received SM for 7 days both before and after I-R. The rats were sacrificed by exsanguination in groups 1-3 at the 24th hour and groups 4 and 5 were sacrificed on the 7th day of reperfusion. Blood and intestinal specimens were taken for biochemical and pathological evaluations.

RESULTS

Serum superoxide dismutase (SOD) and heat shock protein 70 levels were significantly higher in group 2 (5.24 ± 1.76 U/l and 261.4 ± 16.8 ng/ml) compared to the sham group (2.08 ± 1.76 U/l and 189.9 ± 28.7 ng/ml) (p < 0.001 and p < 0.0001, respectively). However, SOD activity and the extent and severity of the histopathological lesions were significantly less in groups 3 [3.11 ± 1.18 U/l, 1.0 (range 0.0-2.0)], 4 [2.15 ± 0.87 U/l, 1.0 (range 1.0-3.0)], and 5 [1.80 ± 0.61 U/l, 0.5 (range 0.0-2.0)], treated with SM, than in group 2 [5.24 ± 1.76 U/l, 2.0 (range 2.0-3.0)] (p = 0.002, p < 0.001, and p = 0.0001; p < 0.001, p = 0.007, and p = 0.0001, respectively). Also, TNF-α levels were lower in the SM-supplemented groups compared to group 2. Serum thiobarbituric acid-reactive substance concentrations were low in the pre-/posttreatment groups treated with SM compared to group 2. No statistical difference was observed for protein carbonyls between the groups.

CONCLUSION

Our findings suggest that SM therapy may attenuate the oxidative and intestinal damage induced by I-R injuries.

Effect of dexmedetomidine pretreatment on lung injury following intestinal ischemia-reperfusion

Reperfusion injury is tissue damage caused by the re-supply of blood following a period of ischemia in tissues. Intestinal ischemia-reperfusion injury (IRI) is an extremely common clinical event associated with distant organ injury. The intestine serves as the initial organ of multi-system organ dysfunction syndrome. It is extremely important to identify a method to protect against IRI, as it is a key factor associated with morbidity and mortality in patients. In the present study, the protective effects of pretreatment with dexmedetomidine hydrochloride were investigated. Rats were divided into six groups and models of intestinal ischemia were created in the five groups. Certain groups were pretreated with dexmedetomidine hydrochloride. The levels of TNF-α and IL-6 were measured by enzyme-linked immunosorbent assay in order to evaluate the injury. Tissue sections were stained with hematoxylin and eosin to visualize the damage. qPCR and western blotting were performed to examine the inflammatory status. Pretreatment with various doses of dexmedetomidine hydrochloride significantly reduced the pathological scores and the inflammatory reaction. The levels of TNF-α, IL-6, TLR4 and MyD88 were decreased in the dexmedetomidine hydrochloride treatment groups compared with those in the sham control and untreated ischemia reperfusion groups. The results of the present study indicate that pretreatment with dexmedetomidine hydrochloride may be a useful method of reducing the damage caused by IRI.

Dexmedetomidine protects against renal ischemia and reperfusion injury by inhibiting the JAK/STAT signaling activation

Background

The α₂-adrenoreceptor agonist dexmedetomidine is known to provide renoprotection against ischemia and reperfusion (I/R) injury. However the underlying molecular mechanisms remain unclear. The purpose of this study was to investigate whether the Janus kinase and signal transducer and activator of transcription (JAK/STAT) signaling pathway plays a role in dexmedetomidine’s renoprotection.

Methods

I/R model was induced by bilateral renal pedicle clamping for 45 min followed by 48 h of reperfusion in male Wistar rat. Sham laparotomy served as controls. Animals received dexmedetomidine (50 μg/kg, i.p.) in the absence or presence of atipamezole (250 μg/kg, i.p.), or vehicle (DMSO) in the absence or presence of selective JAK2 inhibitor tyrphostin AG490 (10 mg/kg, i.p.) before ischemia. Renal function, histology, apoptosis, expression of cleaved caspase 3 protein, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1) and phosphorylations of JAK2, STAT1 and STAT3 were assessed.

Results

The animals treated with either dexmedetomidine or AG490 exhibited an improved renal functional recovery, attenuated histological lesions and reduced number of apoptotic tubular epithelial cells. Either dexmedetomidine or AG490 inhibited the phosphorylations of JAK2 and its downstream molecule STAT1 and STAT3, accompanied by down-regulation the expression of cleaved caspase 3, ICAM-1 and MCP-1 proteins, and significantly ameliorated renal I/R injury.

Conclusions

Dexmedetomidine protects kidney against I/R injury, at least in part, through its inhibitory effects on injury-induced activation of JAK/STAT signaling pathway. If our data can be extrapolated to clinical setting, then dexmedetomidine may therefore serve as a clinical strategy to treat/prevent perioperative renal I/R injury.

The value of signal peptide-CUB-EGF domain-containing protein 1 and oxidative stress parameters in the diagnosis of acute mesenteric ischemia

OBJECTIVES

This study investigated the diagnostic value of signal peptide-CUB-EGF domain-containing protein 1 (SCUBE-1) and other oxidative stress parameters in the early diagnosis of acute mesenteric ischemia, which has high mortality and morbidity if not identified and treated in the early period.

METHODS

Thirty-six female Sprague-Dawley rats were used in this randomized, controlled study. Rats were divided into six groups: three control groups (Groups I, III, and V) and three ischemia groups (Groups II, IV, and VI). In the control groups, blood and tissue specimens were sampled at 30 minutes (Group I), 2 hours (Group III), and 6 hours (Group V), following a simple laparotomy. In the ischemia groups, the superior mesenteric artery (SMA) was ligated following laparotomy, and blood and tissue samples were sampled at 30 minutes (Group II), 2 hours (Group IV), and 6 hours (Group VI).

RESULTS

When comparing the ischemia and control groups, the differences in SCUBE-1, malondialdehyde (MDA), and total antioxidant status (TAS) levels in the 30-minute period were not significant (p > 0.05); at 2 hours, SCUBE-1 levels rose rapidly, and although the desired level of significance could not be obtained with Bonferroni correction, the level was significantly higher compared to the control group at the same time interval (for SCUBE-1, Group III vs. Group IV, p = 0.006). In these periods (30 minutes and 2 hours), only total oxidative status (TOS) and oxidative stress index (OSI) values were significantly higher in the ischemia group compared to the control group (for both, p = 0.004). A pronounced rise in SCUBE-1 levels was determined with 6-hour ischemia (for SCUBE-1, Group V vs. Group VI, p = 0.004). The changes in MDA, TAS, TOS, and OSI levels were not significant (p = 0.025, p = 0.321, p = 0.006, and p = 0.037, respectively).

CONCLUSIONS

SCUBE-1 levels have the potential to be used as a marker of early period injury in acute mesenteric ischemia, although it is impossible to state explicitly that they can be used for early diagnosis. The same can be said for plasma MDA and TAS levels. The authors believe that TOS and OSI levels, however, can be used in early diagnosis and as an injury marker. Moreover, OSI also exhibits a medium-strong correlation with histopathologic injury.