Mitochondrial Dysfunction of Peripheral Platelets as a Predictive Biomarker for Postoperative Delirium in Elderly Patients.

OBJECTIVE: To determine the association between the preoperative Bioenergetic Health Index (BHI) of platelets and the occurrence of postoperative delirium (POD) in elderly patients. METHODS: Elderly patients scheduled for major abdominal surgery under general anesthesia were included. The presence of POD was assessed within the 3 days after surgery. Seahorse XF analysis and transmission electron microscopy were utilized to evaluate the mitochondrial metabolism and morphology of platelets. RESULTS: A total of 20 out of 162 participants developed POD. Participants with POD showed lower preoperative Mini-Mental State Examination scores and total protein levels, fewer educational years, longer surgery duration, higher mean platelet volume, and lower platelet BHI compared with those without POD. Damaged mitochondria with swollen appearance and distorted cristae was detected in platelets from participants with POD. Preoperative platelet BHI was independently associated with the occurrence of POD after adjusting for age, education, preoperative Mini-Mental State Examination score, preoperative mean platelet volume and total protein levels, surgical type and duration, and lymphocyte counts on the first postoperative day (OR 0.11, 95% CI 0.03-0.37, p < 0.001). The areas under the receiver operating curves for predicting POD were 0.83 (95% CI 0.76-0.88) for platelet BHI. It showed a sensitivity of 85.00% and specificity of 73.24%, with an optimal cutoff value of 1.61. Using a serial combination (mean platelet volume followed by BHI) yielded a sensitivity of 80.00% and specificity of 82.39%. INTERPRETATION: Preoperative platelet BHI was independently associated with the occurrence of POD in elderly patients and has the potential as a screening biomarker for POD risk. ANN NEUROL 2024;96:74-86.

Glucose competition between endothelial cells in the blood-spinal cord barrier and infiltrating regulatory T cells is linked to sleep restriction-induced hyperalgesia.

BACKGROUND: Sleep loss is a common public health problem that causes hyperalgesia, especially that after surgery, which reduces the quality of life seriously. METHODS: The 48-h sleep restriction (SR) mouse model was created using restriction chambers. In vivo imaging, transmission electron microscopy (TEM), immunofluorescence staining and Western blot were performed to detect the status of the blood-spinal cord barrier (BSCB). Paw withdrawal mechanical threshold (PWMT) was measured to track mouse pain behavior. The role of infiltrating regulatory T cells (Tregs) and endothelial cells (ECs) in mouse glycolysis and BSCB damage were analyzed using flow cytometry, Western blot, CCK-8 assay, colorimetric method and lactate administration. RESULTS: The 48-h SR made mice in sleep disruption status and caused an acute damage to the BSCB, resulting in hyperalgesia and neuroinflammation in the spinal cord. In SR mice, the levels of glycolysis and glycolysis enzymes of ECs in the BSCB were found significantly decreased [CON group vs. SR group: CD31+Glut1+ cells: p < 0.001], which could cause dysfunction of ECs and this was confirmed in vitro. Increased numbers of infiltrating T cells [p < 0.0001] and Treg population [p < 0.05] were detected in the mouse spinal cord after 48-h SR. In the co-cultured system of ECs and Tregs in vitro, the competition of Tregs for glucose resulted in the glycolysis disorder of ECs [Glut1: p < 0.01, ENO1: p < 0.05, LDHα: p < 0.05; complete tubular structures formed: p < 0.0001; CCK8 assay: p < 0.001 on 24h, p < 0.0001 on 48h; glycolysis level: p < 0.0001]. An administration of sodium lactate partially rescued the function of ECs and relieved SR-induced hyperalgesia. Furthermore, the mTOR signaling pathway was excessively activated in ECs after SR in vivo and those under the inhibition of glycolysis or co-cultured with Tregs in vitro. CONCLUSIONS: Affected by glycolysis disorders of ECs due to glucose competition with infiltrating Tregs through regulating the mTOR signaling pathway, hyperalgesia induced by 48-h SR is attributed to neuroinflammation and damages to the barriers, which can be relieved by lactate supplementation.

Involvement of Spinal Neuroplastin 65 in Neuropathic Pain by GABAA Receptor α2 Subunit Regulation.

BACKGROUND: Neuropathic pain (NP) is a highly challenging condition with complex pathological mechanisms, and the spinal gamma aminobutyric acid A receptor receptor plays a crucial role in its progression. Recent studies have revealed a potential interaction between neuroplastin 65 (NP65) and gamma aminobutyric acid A receptor α2 subunit (GABAAR-α2) on the cell surface. We hypothesize that NP65 is involved in the pathogenesis of NP by regulating the level of GABAAR-α2. METHODS: A chronic constrictive injury (CCI) pain model was established in male Sprague-Dawley rats to verify the change in spinal NP65 expression. Alterations in pain behavior and GABAAR-α2 protein expression were observed after intrathecal injection of NP65 overexpressing adeno-associated virus (AAV) in CCI rats. In vitro investigations on Neuroblastoma 2a cells, the effect of NP65 on GABAAR-α2 expression via the calcineurin-nuclear factor of activated T-cell 4 (CaN-NFATc4) signaling pathway was evaluated by manipulating NP65 expression. RESULTS: The expression level of NP65 protein and mRNA in the CCI group were significantly decreased (P < .05; analysis of variance [ANOVA]). After intrathecal injection of NP65, overexpression of AAV and pain behavior in CCI rats were significantly alleviated, and levels of GABAAR-α2 were upregulated. In vitro experiments verified alterations in the expression of GABAAR-α2, CaN, and phosphorylated NFATc4 on the application of NP65 with plasmid or small interfering RNA, respectively. After the application of the specific CaN inhibitor cyclosporine A (CsA), the changes in NP65 expression did not produce subsequent alterations in the expression of GABAAR-α2, CaN, or phosphorylated NFATc4 proteins. CONCLUSIONS: NP65 modulates the level of GABAAR-α2 through the CaN-NFATc4 signaling pathway, which may serve as the underlying mechanism of NP.

Microglia Promote Inhibitory Synapse Phagocytosis in the Spinal Cord Dorsal Horn and Modulate Pain-Like Behaviors in a Murine Cancer-Induced Bone Pain Model.

BACKGROUND: The microglial activation has been implicated in cancer-induced bone pain. Recent studies have revealed that microglia mediate synaptic pruning in the central nervous system, where the cluster of differentiation 47-signal regulatory protein α (CD47-SIRPα) axis creates a "don't eat me" signal and elicits an antiphagocytic effect to protect synapses against elimination. To date, the synaptic phagocytosis in microglia has never been investigated in the murine cancer-induced bone pain model. The present experiments sought to explore whether microglia phagocytize synapses in mice with bone cancer pain as well as the possible mechanisms. METHODS: Male C3H/HeN mice were used to induce bone cancer pain. Minocycline and S-ketamine were injected into D14. The number of spontaneous flinches (NSF) and paw withdrawal mechanical thresholds (PWMT) were measured on D0, D4, D7, D10, D14, D21, and D28. Hematoxylin and eosin staining presented bone lesions. Western blotting examined the Gephyrin, CD47, and SIRPα expression. Flow cytometry evaluated the proportion of SIRPα+ cells in the spine. Immunofluorescence and 3-dimensional reconstruction showed the Gephyrin puncta inside microglial lysosomes. RESULTS: Mice embedded with tumor cells induced persistent spontaneous pain and mechanical hyperalgesia. Hematoxylin and eosin staining revealed bone destruction and tumor infiltration in marrow cavities. Microglia underwent a responsive and proliferative burst (t = -16.831, P < .001). Western blotting manifested lowered Gephyrin expression in the tumor group (D4, D7, D10, D14, D21, and D28: P < .001). Immunofluorescence and 3-dimensional reconstruction showed larger volumes of Gephyrin puncta inside microglial lysosomes (t = -23.273, P < .001; t = -27.997, P < .001). Treatment with minocycline or S-ketamine exhibited pain relief and antiphagocytic effects (t = -6.191, P < .001, t = -7.083, P < .001; t = -20.767, P < .001, t = -17.080, P < .001; t = 11.789, P < .001, t = 16.777, P < .001; t = 8.868, P < .001, t = 21.319, P < .001). Last but not least, the levels of CD47 and SIRPα proteins were downregulated (D10: P = .004, D14, D21, and D28: P < .001; D10, D14, D21, and D28: P < .001). Flow cytometry and immunofluorescence substantiated reduced microglial SIRPα (t = 11.311, P < .001; t = 12.189, P < .001). CONCLUSIONS: Microglia-mediated GABAergic synapse pruning in the spinal cord dorsal horn in bone cancer pain mice, which might be associated with the declined CD47-SIRPα signal. Our research uncovered an innovative mechanism that highlighted microglia-mediated synaptic phagocytosis in a murine cancer-induced bone pain model.

Impact of sarcopenia in elderly patients undergoing elective total hip arthroplasty on postoperative outcomes: a propensity score-matched study.

OBJECTIVE: Frailty poses a crucial risk for postoperative complications in the elderly, with sarcopenia being a key component. The impact of sarcopenia on postoperative outcomes after total hip arthroplasty (THA) is still unclear. This study investigated the potential link between sarcopenia and postoperative outcomes among elderly THA patients. METHODS: Totally 198 older patients were enrolled in this study. Sarcopenia in this group was determined by assessing the skeletal muscle index, which was measured using computed tomography at the 12th thoracic vertebra and analyzed semi-automatically with MATLAB R2020a. Propensity score matching (PSM) was employed to evaluate postoperative complications of grade II and above (POCIIs). RESULTS: The variables balanced using PSM contained age, sex and comorbidities including hypertension, diabetes, hyperlipidemia and COPD. Before PSM, sarcopenic patients with reduced BMI (24.02 ± 0.24 vs. 27.11 ± 0.66, P < 0.001) showed higher POCIIs rates (48.31% vs. 15%, P = 0.009) and more walking-assisted discharge instances (85.96% vs. 60%, P = 0.017) compared with non-sarcopenia patients. After PSM, this group maintained reduced BMI (23.47 ± 0.85 vs. 27.11 ± 0.66, P = 0.002), with increased POCIIs rates (54.41% vs. 15%, P = 0.002) and heightened reliance on walking assistance at discharge (86.96% vs. 60%, P = 0.008). CONCLUSION: Sarcopenia patients exhibited a higher incidence of POCIIs and poorer physical function at discharge. Sarcopenia could serve as a valuable prognostic indicator for elderly patients undergoing elective THA.

The effects of robot-assisted laparoscopic surgery with Trendelenburg position on short-term postoperative respiratory diaphragmatic function.

OBJECTIVE: To study how Pneumoperitoneum under Trendelenburg position for robot-assisted laparoscopic surgery impact the perioperative respiratory parameters, diagrammatic function, etc. METHODS: Patients undergoing robot-assisted laparoscopic surgery in the Trendelenburg position and patients undergoing general surgery in the supine position were selected. The subjects were divided into two groups according to the type of surgery: robot-assisted surgery group and general surgery group. ① Respiratory parameters such as lung compliance, oxygenation index, and airway pressure were recorded at 5 min after intubation, 1 and 2 h after pneumoperitoneum. ② Diaphragm excursion (DE) and diaphragm thickening fraction (DTF) were recorded before entering the operating room (T1), immediately after extubation (T2), 10 min after extubation (T3), and upon leaving the postanesthesia care unit (T4). ③ Peripheral venous blood (5 ml) was collected before surgery and 30 min after extubation and was analyzed by enzyme-linked immunosorbent assay to determine the serum concentration of Clara cell secretory protein 16 (CC16) and surfactant protein D (SP-D). RESULT: ① Compared with the general surgery group (N = 42), the robot-assisted surgery group (N = 46) presented a significantly higher airway pressure and lower lung compliance during the surgery(P < 0.001). ② In the robot-assisted surgery group, the DE significantly decreased after surgery (P < 0.001), which persisted until patients were discharged from the PACU (P < 0.001), whereas the DTF only showed a transient decrease postoperatively (P < 0.001) and returned to its preoperative levels at discharge (P = 0.115). In the general surgery group, the DE showed a transient decrease after surgery(P = 0.011) which recovered to the preoperative levels at discharge (P = 1). No significant difference in the DTF was observed among T1, T2, T3, and T4. ③ Both the general and robot-assisted surgery reduced the postoperative serum levels of SP-D (P < 0.05), while the robot-assisted surgery increased the postoperative levels of CC16 (P < 0.001). CONCLUSION: Robot-assisted laparoscopic surgery significantly impairs postoperative diaphragm function, which does not recover to preoperative levels at PACU discharge. Elevated levels of serum CC16 after surgery suggest potential lung injury. The adverse effects may be attributed to the prolonged Trendelenburg position and pneumoperitoneum during laparoscopic surgery.

Overall Description and Predictors of Disruptive Behavior Toward Nurses in the Perioperative Arena.

PURPOSE: To investigate the prevalence, characteristics, causes, consequences, and predictors of and responses to disruptive behavior toward nurses in the perioperative arena. DESIGN: A cross-sectional design using a network questionnaire platform. METHODS: Nurses in the perioperative arena were recruited online in March 2020. Data on disruptive behavior toward nurses in the past 6 months and nurses' sociodemographic and environmental factors were collected. FINDINGS: Nurses (N = 496) responded validly to the survey. In total, 82.1% of participants experienced disruptive behavior. Assignment of overwhelming workloads and verbal aggression were the most common behaviors, and surgeons were the major perpetrators. Perpetrators' intrapersonal issues were the most commonly perceived causes. A positive strategy was the most common strategy adopted by participants. Further, 80.8% of participants recounted their negative experiences, and more than half of respondents (59.9%) talked with their nursing colleagues. Nearly half of respondents (45.9%) did not report disruptive behavior. Negative emotions as an immediate effect were reported by 53.1% of the participants, and the most common long-term impact was decreased passion for work. Middle age, job position, practice environment, and system help were risk factors for experiencing disruptive behavior. CONCLUSIONS: The prevalence of disruptive behavior toward nurses in the perioperative arena is high, and its ramifications should not be ignored. Health care institutions should urgently implement intervention strategies to reduce disruptive behavior toward nurses.

Dexmedetomidine adjunct to ropivacaine for ultrasound-guided transversus abdominis plane block for open inguinal hernia repair in the older adults: A randomised clinical trial.

OBJECTIVE: The aim of this study was to evaluate the effect of adding dexmedetomidine to ropivacaine on pain relief and quality of recovery in older patients undergoing open inguinal hernia repair surgeries. METHODS: This was a prospective and randomised clinical trial of 102 patients aged over 65 years who received an ultrasound-guided transversus open mesh herniorrhaphy abdominis plane (TAP) block with either 0.375% ropivacaine 20 ml (Group R, n = 47) or 0.375% ropivacaine combined with 1 µg/kg dexmedetomidine 20 ml (Group RD, n = 45) in the pre-anaesthesia care unit before elective open inguinal hernia surgeries. The primary outcome measure was Visual Analogue Scale (VAS) pain scores at rest and on movement at 2, 4, 8, 12 and 24 h and at 1 and 3 months' postoperatively. The secondary outcome measures were the incidence of post-operative delirium (POD), nausea and vomiting and the occurrence of side effects or complications on post-operative day 1. RESULTS: Group RD had lower VAS scores at rest and on movement at 8 and 12 h postoperatively and a lower incidence of POD on the post-operative day 1 than Group R. Transient bradycardia was more frequent in Group RD than in Group R, and side effects or post-operative complications were reported in either group. CONCLUSION: The addition of dexmedetomidine to ropivacaine in a TAP block enhances postoperative analgesia during hospitalisation and improves the quality of recovery without affecting chronic pain in older patients undergoing open inguinal hernia repair surgery.

Dehydrocorydaline alleviates sleep deprivation-induced persistent postoperative pain in adolescent mice through inhibiting microglial P2Y12 receptor expression in the spinal cord.

During adolescence, a second period of central nervous system (CNS) plasticity that follows the fetal period, which involves sleep deprivation (SD), becomes apparent. SD during adolescence may result in abnormal development of neural circuits, causing imbalance in neuronal excitation and inhibition, which not only results in pain, but increases the chances of developing emotion disorders in adulthood, such as anxiety and depression. The quantity of surgeries during adolescence is also consistently on the rise, yet the impact and underlying mechanism of preoperative SD on postoperative pain remain unexplored. This study demonstrates that preoperative SD induces upregulation of the P2Y12 receptor, which is exclusively expressed on spinal microglia, and phosphorylation of its downstream signaling pathway p38Mitogen-activated protein/Nuclear transcription factor-κB (p38MAPK/NF-κB)in spinal microglia, thereby promoting microglia activation and microglial transformation into the proinflammatory M1 phenotype, resulting in increased expression of proinflammatory cytokines that exacerbate persisting postoperative incisional pain in adolescent mice. Both intrathecal minocycline (a microglia activation inhibitor) and MRS2395 (a P2Y12 receptor blocker) effectively suppressed microglial activation and proinflammatory cytokine expression. Interestingly, supplementation with dehydrocorydaline (DHC), an extract of Rhizoma Corydalis, inhibited the P2Y12/p38MAPK/NF-κB signaling pathway, microglia activation, and expression of pro-inflammatory cytokines in the model mice. Taken together, the results indicate that the P2Y12 receptor and microglial activation are important factors in persistent postoperative pain caused by preoperative SD in adolescent mice and that DHC has analgesic effects by acting on these targets.

Exosomal PGE2 from M2 macrophages inhibits neutrophil recruitment and NET formation through lipid mediator class switching in sepsis.

BACKGROUND: Excess polymorphonuclear neutrophil (PMN) recruitment or excessive neutrophil extracellular trap (NET) formation can lead to the development of multiple organ dysfunction during sepsis. M2 macrophage-derived exosomes (M2-Exos) have exhibited anti-inflammatory activities in some inflammatory diseases to mediate organ functional protection, but their role in treating sepsis-related acute lung injury (ALI) remains unclear. In this study, we sought to investigate whether M2-Exos could prevent potentially deleterious inflammatory effects during sepsis-related ALI by modulating abnormal PMN behaviours. METHODS: C57BL/6 wild-type mice were subjected to a caecal ligation and puncture (CLP) mouse model to mimic sepsis in vivo, and M2-Exos were administered intraperitoneally 1 h after CLP. H&E staining, immunofluorescence and immunohistochemistry were conducted to investigate lung tissue injury, PMN infiltration and NET formation in the lung. We further demonstrated the role of M2-Exos on PMN function and explored the potential mechanisms through an in vitro coculture experiment using PMNs isolated from both healthy volunteers and septic patients. RESULTS: Here, we report that M2-Exos inhibited PMN migration and NET formation, alleviated lung injury and reduced mortality in a sepsis mouse model. In vitro, M2-Exos significantly decreased PMN migration and NET formation capacity, leading to lipid mediator class switching from proinflammatory leukotriene B4 (LTB4) to anti-inflammatory lipoxin A4 (LXA4) by upregulating 15-lipoxygenase (15-LO) expression in PMNs. Treatment with LXA4 receptor antagonist attenuated the effect of M2-Exos on PMNs and lung injury. Mechanistically, prostaglandin E2 (PGE2) enriched in M2-Exos was necessary to increase 15-LO expression in PMNs by functioning on the EP4 receptor, upregulate LXA4 production to downregulate chemokine (C-X-C motif) receptor 2 (CXCR2) and reactive oxygen species (ROS) expressions, and finally inhibit PMN function. CONCLUSIONS: Our findings reveal a previously unknown role of M2-Exos in regulating PMN migration and NET formation through lipid mediator class switching, thus highlighting the potential application of M2-Exos in controlling PMN-mediated tissue injury in patients with sepsis.

Pretreatment of the ROS Inhibitor Phenyl-N-tert-butylnitrone Alleviates Sleep Deprivation-Induced Hyperalgesia by Suppressing Microglia Activation and NLRP3 Inflammasome Activity in the Spinal Dorsal Cord.

Sleep deprivation, a common perioperative period health problem, causes ocular discomfort and affects postsurgical pain. However, the mechanism of sleep deprivation-induced increased pain sensitivity is elusive. This study aims to explore the role of ROS in sleep deprivation (SD)-induced hyperalgesia and the underlying mechanism. A 48-h continuous SD was performed prior to the hind paw incision pain modeling in mice. We measured ROS levels, microglial activation, DNA damage and protein levels of iNOS, NLRP3, p-P65 and P65 in mouse spinal dorsal cord. The involvement of ROS in SD-induced prolongation of postsurgical pain was further confirmed by intrathecal injection of ROS inhibitor, phenyl-N-tert-butylnitrone (PBN). Pretreatment of 48-h SD in mice significantly prolonged postsurgical pain recovery, manifesting as lowered paw withdrawal mechanical threshold and paw withdrawal thermal latency. It caused ROS increase and upregulation of iNOS on both Day 1 and 7 in mouse spinal dorsal cord. In addition, upregulation of NLRP3 and p-P65, microglial activation and DNA damage were observed in mice pretreated with 48-h SD prior to the incision. Notably, intrathecal injection of PBN significantly reversed the harmful effects of SD on postsurgical pain recovery, hyperalgesia, microglial activation and DNA damage via the NF-κB signaling pathway. Collectively, ROS increase is responsible for SD-induced hyperalgesia through activating microglial, triggering DNA damage and enhancing NLRP3 inflammasome activity in the spinal dorsal cord.

Proinflammatory activation of microglia in the cerebellum hyperexcites Purkinje cells to trigger ataxia.

Specific medications to combat cerebellar ataxias, a group of debilitating movement disorders characterized by difficulty with walking, balance and coordination, are still lacking. Notably, cerebellar microglial activation appears to be a common feature in different types of ataxic patients and rodent models. However, direct evidence that cerebellar microglial activation in vivo is sufficient to induce ataxia is still lacking. Here, by employing chemogenetic approaches to manipulate cerebellar microglia selectively and directly, we found that specific chemogenetic activation of microglia in the cerebellar vermis directly leads to ataxia symptoms in wild-type mice and aggravated ataxic motor deficits in 3-acetylpyridine (3-AP) mice, a classic mouse model of cerebellar ataxia. Mechanistically, cerebellar microglial proinflammatory activation induced by either chemogenetic M3D(Gq) stimulation or 3-AP modeling hyperexcites Purkinje cells (PCs), which consequently triggers ataxia. Blockade of microglia-derived TNF-α, one of the most important proinflammatory cytokines, attenuates the hyperactivity of PCs driven by microglia. Moreover, chemogenetic inhibition of cerebellar microglial activation or suppression of cerebellar microglial activation by PLX3397 and minocycline reduces the production of proinflammatory cytokines, including TNF-α, to effectively restore the overactivation of PCs and alleviate motor deficits in 3-AP mice. These results suggest that cerebellar microglial activation may aggravate the neuroinflammatory response and subsequently induce dysfunction of PCs, which in turn triggers ataxic motor deficits. Our findings thus reveal a causal relationship between proinflammatory activation of cerebellar microglia and ataxic motor symptoms, which may offer novel evidence for therapeutic intervention for cerebellar ataxias by targeting microglia and microglia-derived inflammatory mediators.

SIRT2 overexpression decreases remifentanil-stimulated post-surgical hyperalgesia via microglia.

Remifentanil (Remi)-induced hyperalgesia is a serious but common postoperative clinical problem. Sirtuin 2 (SIRT2) is essential in the pathogenetic mechanisms of several neurological disorders. However, whether SIRT2 contributes to the modulation of Remi-induced postsurgical hyperalgesia (POH) is unknown. Here, we investigated the regulatory potential of SIRT2 in Remi-stimulated POH. A rat Remi-stimulated POH model was built by infusing Remi in the surgical incision. Mechanical allodynia and thermal hyperalgesia were separately assessed by paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) measurements. SIRT2 and binding adaptor molecule 1 (Iba1) protein expressions and localization in spinal cord samples were detected by western blot and immunofluorescence. The results revealed SIRT2 downregulation in the spinal cord of rats with Remi-stimulated POH. Intrathecal administration of the overexpression plasmid harboring SIRT2 remarkably relieved mechanical allodynia, along with thermal hyperalgesia in the model animals. Iba1 amounts were increased upon intraoperative incision or Remi infusion, and this effect was more pronounced upon combining both treatments. Furthermore, SIRT2 overexpression suppressed microglia activation in the spinal cord of model animals, and starkly relieved incision- and/or Remi-associated pronociceptive processes as well as spinal microglia activation. SIRT2 elevation relieved Remi-associated POH, likely by suppressing spinal microglia activation. Thus, SIRT2 could be a potent target for treating neuropathic pain.

Inhibition of Cyclophilin A-Metalloproteinase-9 Pathway Alleviates the Development of Neuropathic Pain by Promoting Repair of the Blood-Spinal Cord Barrier.

BACKGROUND: Dysfunction of the blood-spinal cord barrier (BSCB) contributes to the occurrence and development of neuropathic pain (NP). Previous studies revealed that the activation of cyclophilin A (CypA)-metalloproteinase-9 (MMP9) signaling pathway can disrupt the integrity of the blood-brain barrier (BBB) and aggravate neuroinflammatory responses. However, the roles of CypA-MMP9 signaling pathway on BSCB in NP have not been studied. This study aimed to investigate the effect of CypA on the structure and function of the BSCB and pain behaviors in mice with NP. METHODS: We first created the mouse chronic constriction injury (CCI) model, and they were then intraperitoneally injected with the CypA inhibitor cyclosporine A (CsA) or vehicle. Pain behaviors, the structure and function of the BSCB, the involvement of the CypA-MMP9 signaling pathway, microglia activation, and expression levels of proinflammatory factors in mice were examined. RESULTS: CCI mice presented mechanical allodynia and thermal hyperalgesia, impaired permeability of the BSCB, downregulated tight junction proteins, activated CypA-MMP9 signaling pathway, microglia activation, and upregulated proinflammatory factors, which were significantly alleviated by inhibition of CypA. CONCLUSIONS: Collectively, the CypA-MMP9 signaling pathway is responsible for CCI-induced NP in mice by impairing the structure and function of the BSCB, and activating microglia and inflammatory responses.

HuB and HuD repress telomerase activity by dissociating HuR from TERC.

The ubiquitous RNA-binding protein HuR (ELAVL1) promotes telomerase activity by associating with the telomerase noncoding RNA TERC. However, the role of the neural-specific members HuB, HuC, and HuD (ELAVL2-4) in telomerase activity is unknown. Here, we report that HuB and HuD, but not HuC, repress telomerase activity in human neuroblastoma cells. By associating with AU-rich sequences in TERC, HuB and HuD repressed the assembly of the TERT-TERC core complex. Furthermore, HuB and HuD competed with HuR for binding to TERC and antagonized the function of HuR that was previously shown to enhance telomerase activity to promote cell growth. Our findings reveal a novel mechanism controlling telomerase activity in human neuroblastoma cells that involves a competition between HuR and the related, neural-specific proteins HuB and HuD.

A Single Preoperative Dose of S-Ketamine Has No Beneficial Effect on Chronic Postsurgical Pain in Patients Undergoing Video-Assisted Thoracoscopic Surgical Lung Lesion Resection: A Prospective Randomized Controlled Study.

OBJECTIVES: To evaluate the efficacy of a single preoperative dose of S-ketamine for chronic postsurgical pain (CPSP) in patients undergoing video-assisted thoracoscopic surgical lung lesion resection (VATS). DESIGN: A prospective randomized, double-blind controlled study. SETTING: Patients were enrolled from March 17, 2021, to November 18, 2021, at a single tertiary academic hospital. PARTICIPANTS: Patients were 18-to-65 years of age and undergoing VATS. INTERVENTIONS: The experiment was divided into an S-ketamine group (0.5 mg/kg intravenous injection before anesthesia induction) or a placebo group (the same volume of normal saline). MEASUREMENTS AND MAIN RESULTS: The primary endpoint was the incidence of CPSP and its neuropathic component. The secondary endpoints included acute postoperative pain, the use of postoperative analgesics, anxiety and sleep quality scores, and the occurrence of adverse effects. There were no significant differences between the 2 groups in the incidences of CPSP, neuropathic pain, acute postoperative pain, and postoperative use of analgesics. The sleep quality scores on the first postoperative day differed significantly between the groups (47.45 ± 27.58 v . 52.97 ± 27.57, p = 0.049), but not the anxiety scores. In addition, adverse effects were similar between the 2 groups. CONCLUSIONS: A single preoperative dose of S-ketamine in patients who underwent VATS had no significant effect on acute and chronic postoperative pain or the consumption of analgesics after surgery. A single preoperative dose of S-ketamine could improve sleep on the first day after surgery, whereas it had no significant effect on anxiety levels.

Predictors of Chronic Pain in Elderly Patients Undergoing Total Knee and Hip Arthroplasty: A Prospective Observational Study.

BACKGROUND: Chronic postsurgical pain (CPSP) after total knee arthroplasty and total hip arthroplasty (TKA and THA) is an important clinical problem in which many factors play a role. The risk factors for CPSP in elderly individuals are currently unknown. Therefore, our aim was to predict the risk factors for CPSP after TKA and THA and to provide help regarding early screening and interventions for elderly individuals at risk. METHODS: In this prospective observational study, we collected and analyzed 177 TKA patients and 80 THA patients. Based on pain results at the 3-month follow-up, they were divided into the no chronic postsurgical pain and CPSP groups, respectively. The preoperative baseline conditions, including pain intensity (Numerical Rating Scale) and sleep quality (Pittsburgh Sleep Quality Index), as well as intraoperative and postoperative factors, were compared. Factors with P < .05 were included in binary regression analyses to establish prediction models for CPSP after TKA and THA. RESULTS: The prevalence of CPSP was 20.9% after TKA and 7.5% after THA. The preoperative sleep disorders were an independent risk factor of CPSP after TKA, but no risk factors of CPSP after THA were identified. CONCLUSION: This study indicated that the prevalence of CPSP after TKA was significantly higher than after THA, and that preoperative sleep disorders were an independent risk factor for CPSP after TKA, which may aid clinicians in screening people at risk for CPSP for primary prevention.

Connexin 43 gap junction-mediated astrocytic network reconstruction attenuates isoflurane-induced cognitive dysfunction in mice.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a common complication following anesthesia and surgery. General anesthetic isoflurane has potential neurotoxicity and induces cognitive impairments, but the exact mechanism remains unclear. Astrocytes form interconnected networks in the adult brain through gap junctions (GJs), which primarily comprise connexin 43 (Cx43), and play important roles in brain homeostasis and functions such as memory. However, the role of the GJ-Cx43-mediated astrocytic network in isoflurane-induced cognitive dysfunction has not been defined. METHODS: 4-month-old male C57BL/6 mice were exposure to long-term isoflurane to induce cognitive impairment. To simulate an in vitro isoflurane-induced cognitive dysfunction-like condition, primary mouse astrocytes were subjected to long-term isoflurane exposure. Cognitive function was assessed by Y-maze and fear conditioning tests. Western blot was used to determine the expression levels of different functional configurations of Cx43. The morphology of the GJs-Cx43 was evaluated by immunofluorescence staining. Levels of IL-1ß and IL-6 were examined by ELISA. The ability of GJs-Cx43-mediated intercellular communication was examined by lucifer yellow dye transfer assay. Ethidium bromide uptake assays were used to measure the activity of Cx43 hemichannels. The ultrastructural morphology of astrocyte gap junctions and tripartite synapse were observed by transmission electron microscopy. RESULTS: After long-term isoflurane anesthesia, the GJs formed by Cx43 in the mouse hippocampus and primary mouse astrocytes were significantly reduced, GJs function was impaired, hemichannel activity was enhanced, the levels of IL-1ß and IL-6 were increased, and mice showed significant cognitive impairment. After treatment with the novel GJ-Cx43 enhancer ZP1609, GJ-Cx43-mediated astrocytic network function was enhanced, neuroinflammation was alleviated, and ameliorated cognition dysfunction induced by long-term isoflurane exposure. However, ZP1609 enhances the astrocytic network by promoting Cx43 to form GJs without affecting hemichannel activity. Additionally, our data showed that long-term isoflurane exposure does not alter the structure of tripartite synapse. CONCLUSION: Our results reveal a novel mechanism of the GJ-Cx43-mediated astrocytic network involved in isoflurane-induced neuroinflammation and cognitive impairments, which provides new mechanistic insight into the pathogenesis of POCD and identifies potential targets for its treatment.

The role of 5-HT7R in the memory impairment of mice induced by long-term isoflurane anesthesia.

General anesthesia is widely utilized in the clinic for surgical and diagnostic procedures. However, growing evidence suggests that anesthetic exposure may affect cognitive function negatively. Unfortunately, little is known about the underlying mechanisms and efficient prevention and therapeutic strategies for the anesthesia-induced cognitive dysfunction. 5-HT7R, a serotonin receptor family member, is functionally associated with learning and memory. It has recently become a potential therapeutic target in various neurological diseases as its ligands have a wide range of neuropharmacological effects. However, it remains unknown the role of 5-HT7R in the long-term isoflurane anesthesia-induced memory impairment and whether prior activation or blockade of 5-HT7R before anesthesia has modulating effects on this memory impairment. In this study, 5-HT7R selective agonist LP-211 and 5-HT7R selective antagonist SB-269970 were pretreated intraperitoneally to mice before anesthesia; their effects on the cognitive performance of mice were assessed using fear conditioning test and novel object recognition test. Furthermore, the transcriptional level of 5-HT7R in the hippocampus was detected using qRT-PCR, and proteomics was conducted to probe the underlying mechanisms. As a result, long-term exposure to isoflurane anesthesia caused memory impairment and an increase in hippocampal 5-HT7R mRNA expression, which could be attenuated by SB-269970 pretreatment but not LP-211pretreatment. According to the proteomics results, the antiamnestic effect of SB-269970 pretreatment was probably attributed to its action on the gene expression of Slc6a11, Itpka, Arf3, Srcin1, and Epb41l2, and synapse organization in the hippocampus. In conclusion, 5-HT7R is involved in the memory impairment induced by long-term isoflurane anesthesia, and the prior blockade of 5-HT7R with SB-269970 protects the memory impairment. This finding may help to improve the understanding of the long-term isoflurane anesthesia-induced memory impairment and to construct potential preventive and therapeutic strategies for the adverse effects after long-term isoflurane exposure.

Basolateral Amygdala Reactive Microglia May Contribute to Synaptic Impairment and Depressive-Like Behavior in Mice with Bone Cancer Pain.

Anxiety and depression induced by cancer-related pain disturb quality of life and willingness to survive. As a component of the limbic system, the basolateral amygdala (BLA) is critical for processing negative emotions. The reactive microglial engulfment of synapses may promote depression during adolescence. However, whether microglia phagocytose synapses to mediate cancer pain-induced depression remains unclear. The present study established a bone cancer-pain model to investigate the association between dendritic spine synapses and depressive-like behavior and explore the phagocytic function of microglia in the BLA. We found that tumor-bearing mice experienced postoperative pain-related depression, and their BLAs exhibited reactive microglia, as well as phagocytic synapses. The microglial inhibitor minocycline effectively mitigated depressive behavior, synaptic damage, and the phagocytic function of microglia. Our study implicates microglia-mediated synaptic loss in the BLA may act as the pathological basis of depressive-like behavior in bone cancer pain model.