Single-Cell RNA-Sequencing Reveals the Active Involvement of Macrophage Polarizations in Pulmonary Hypertension.

Background: Sustained hypoxia can trigger a progressive rise in pulmonary artery pressure and cause serious pulmonary diseases. Macrophages play important roles along the progression of pulmonary hypertension. However, the state of macrophage polarization during the early stage of pulmonary hypertension is unclear. Methods: Unlike traditional sequencing method, single-cell sequencing can accurately distinguish among cell types and better understand cell-to-cell relationships. In this study, we investigated the polarization of macrophages in pulmonary hypertension via single-cell RNA-sequencing in a mice hypoxia model, which was then validated in patients with pulmonary hypertension. Results: We identified that the intermittent exposure to hypoxic conditions could lead to the production of more M2-type macrophages than M1-type macrophages in a mouse model. Further validation analysis was performed by analyzing lung tissue of patients with pulmonary hypertension, revealing that the number of disease-associated M2 macrophages was substantially increased. Conclusions: In this study, the active anti-inflammatory response of macrophage involved in pulmonary hypertension has been identified, suggesting that intervention against the polarization of macrophages to the M2 type may be a potential way to reduce chronic pulmonary inflammation, pulmonary vascular remodeling, and artery pressure. Thus, investigation of macrophage polarization associated with hypoxia could help us better understand disease mechanism and craft effective prevention strategies and approaches.

Recent advances in double-lumen tube malposition in thoracic surgery: A bibliometric analysis and narrative literature review.

Thoracic surgery has increased drastically in recent years, especially in light of the severe outbreak of the 2019 novel coronavirus disease (COVID-19). Routine "passive" chest computed tomography (CT) screening of inpatients detects some pulmonary diseases requiring thoracic surgeries timely. As an essential device for thoracic anesthesia, the double-lumen tube (DLT) is particularly important for anesthesia and surgery. With the continuous upgrading of the DLTs and the widespread use of fiberoptic bronchoscopy (FOB), the position of DLT in thoracic surgery is gradually becoming more stable and easier to observe or adjust. However, DLT malposition still occurs during transferring patients from a supine to the lateral position in thoracic surgery, which leads to lung isolation failure and hypoxemia during one-lung ventilation (OLV). Recently, some innovative DLTs or improved intervention methods have shown good results in reducing the incidence of DLT malposition. This review aims to summarize the recent studies of the incidence of left-sided DLT malposition, the reasons and effects of malposition, and summarize current methods for reducing DLT malposition and prospects for possible approaches. Meanwhile, we use bibliometric analysis to summarize the research trends and hot spots of the DLT research.

Protective Effects of Rocuronium Bromide on Ischemia-Reperfusion Injury in Skeletal Muscle Induced by Tourniquet in Patients Undergoing Elective Unilateral Total Knee Arthroplasty: A Prospective, Double Blind, Randomized, Controlled Study.

PURPOSE: To investigate the effects of different doses of rocuronium on ischemia-reperfusion injury in skeletal muscle induced by tourniquet in patients undergoing elective unilateral total knee arthroplasty. PATIENTS AND METHODS: A total of 90 patients undergoing elective unilateral knee arthroplasty under general anesthesia combined with femoral nerve block were randomly divided into 3 groups: normal saline group (group S), rocuronium 0.6 mg/kg group (group L), and rocuronium 1.2 mg/kg group (group H). The primary outcome was the expression of dystrophin in skeletal muscle at 60 min after ischemia. Secondary outcomes included the concentration of malondialdehyde (MDA) and neuronal nitric oxide synthase (nNOS) in blood at 5 min and 30 min after reperfusion. In addition, thigh girth at 24 h and 48 h after operation, the leaving bed time, the incidence of tourniquet-related hypertension and short-term (3 days after operation) complications (nausea and vomiting, swelling, blister, wound infection) and long-term (3 months after operation) complications (joint instability, stiffness, nerve paralysis, pain) were recorded. MAIN RESULTS: The expression of dystrophin in the rocuronium group was higher than that in group S after ischemia (P <0.05). The concentration of MDA in the rocuronium 1.2 mg/kg group was lower at 30 min after reperfusion (P < 0.05). There was no significant difference in nNOS among groups at each time point (P > 0.05). The change of thigh girth was the smallest in the rocuronium 1.2 mg/kg group after operation (P<0.05). The leaving bed time was significantly earlier after operation in the rocuronium group than that in group S (P <0.05). CONCLUSION: Rocuronium can protect skeletal muscle from ischemia-reperfusion injury induced by tourniquet. The mechanism may be related to the fact that rocuronium can reduce the loss of dystrophin in skeletal muscle and have the effects of anti-oxidation and anti-stress. TRIAL REGISTRATION: The study was registered at http://www.chictr.org.cn (ChiCTR1800019221, registered on 2018-10-31).

Effects of intraoperative dexmedetomidine with intravenous anesthesia on postoperative emergence agitation/delirium in pediatric patients undergoing tonsillectomy with or without adenoidectomy: A CONSORT-prospective, randomized, controlled clinical trial.

Postoperative emergence agitation/delirium (POED) is a common complication in pediatric surgery patients, which increases the risk of developing postoperative airway obstruction and respiratory depression. This study aims to investigate the safety and efficacy of intraoperative infusion of dexmedetomidine (DEX) and its effects on POED in pediatric patients undergoing tonsillectomy with or without adenoidectomy.Sixty patients scheduled for tonsillectomy with or without adenoidectomy, aged 2 to 8 years, were randomly allocated into 2 groups (n = 30). Pediatric patients in the group DEX received intravenous (IV) DEX 1 µg/kg over 10 minutes, followed by 0.5 µg/kg/h continuous infusion, and the same volume of 0.9% saline was administrated in the group control. Anesthesia was maintained with target-controlled infusion (TCI) of propofol and remifentanyl. Intraoperative heart rate (HR), noninvasive blood pressure (NIBP), blood oxygen saturation (SPO2), recovery time, and extubation time were recorded. Pain level was evaluated using the objective pain score (OPS), pediatric anesthesia emergence delirium (PAED) scale and Cole 5-point scale (CPS) was used to evaluate POED when patients at 0, 5, 15 minutes, and then at intervals of 15 minutes for 60 minutes after parents arrival at postanesthesia care unit (PACU).The results showed that intraoperative HR was significantly lower in group DEX (P <0.05), mean diastolic and systolic NIBP was not statistically different between groups. Time to wake and time to extubation were lengthened in group DEX as compared with group control (P <0.05). OPS and CPS were lower in group DEX at 15, 30, and 45 minutes time points (P <0.05); however, there were no significantly differences in the PAED score at different time points in the PACU.The present data suggested that intraoperative infusion of dexmedetomidine combined with intravenous anesthetics can provide satisfactory intraoperative conditions for pediatric patients undergoing tonsillectomy with or without adenoidectomy, without adverse hemodynamic effects, though the lower incidence of POED was not observed.

Role of the cerebrospinal fluid-contacting nucleus in the descending inhibition of spinal pain transmission.

The brainstem is well recognized as a critical site for integrating descending modulatory systems that both inhibit and facilitate pain at the level of the spinal cord. The cerebrospinal fluid-contacting nucleus (CSF-contacting nucleus) distributes and localizes in the ventral periaqueductal central gray of the brainstem. Although emerging lines of evidence suggest that the CSF-contacting nucleus may be closely linked to transduction and regulation of pain signals, the definitive role of the CSF-contacting nucleus in pain modulation remains poorly understood. In the present study, we determined the role of the CSF-contacting nucleus in rat nocifensive behaviors after persistent pain by targeted ablation of the CSF-contacting nucleus in the brainstem using the cholera toxin subunit B-saporin (CB-SAP), a cytotoxin coupled to cholera toxin subunit B. Compared with CB/SAP, CB-SAP induced complete ablation of the CSF-contacting nucleus, and the CB-SAP-treated rats showed hypersensitivity in responses to acute nociceptive stimulation, and exacerbated spontaneous nocifensive responses induced by formalin, thermal hyperalgesia and mechanical allodynia induced by plantar incision. Furthermore, immunohistochemical experiments showed that the CSF-contacting nucleus was a cluster of 5-HT-containing neurons in the brainstem, and the spinal projection of serotonergic axons originating from the CSF-contacting nucleus constituted the descending 5-HT pathway to the spinal cord. CB-SAP induced significant downregulation of 5-HT in the spinal dorsal horn, and intrathecal injection of 5-HT significantly reversed hypersensitivity in responses to acute nociceptive stimulation in the CB-SAP-treated rats. These results indicate that the CSF-contacting nucleus 5-HT pathway is an important component of the endogenous descending inhibitory system in the control of spinal nociceptive transmission.

Extracellular signal-regulated kinase 5 in the cerebrospinal fluid-contacting nucleus contributes to morphine physical dependence in rats.

The cerebrospinal fluid-contacting nucleus (CSF-CN) may influence actual composition of the CSF for non-synaptic signal transmission via releasing or absorbing bioactive substances, which distributes and localizes in the ventral periaqueductal central gray of the brainstem. Previous studies demonstrated that CSF-CN was involved in neuropathic pain and morphine dependence. Thus, to identify whether extracellular signal-regulated kinase 5 (ERK5) distributed in the CSF-CN and its function on the formation and development of morphine physical dependence, morphine withdrawal-like behavioral test and immunofluorescent technique were used in this research. Morphine was subcutaneously injected by an intermittent and escalating procedure to induce physical dependence, which was measured by withdrawal symptoms. In this study, we found that horseradish peroxidase-conjugated toxin subunit B/p-ERK5 double-labeled neurons expressed in the CSF-CN of normal rats. ERK5 signaling pathway was remarkably activated by naloxone-precipitated withdrawal in the CSF-CN. Moreover, selective attenuation of p-ERK5 expression in the CSF-CN by lateral ventricle injection of BIX02188 could significantly relieve morphine withdrawal symptom. These findings confirmed that the activation of p-ERK5 in the CSF-CN might contribute to morphine physical dependence.

Activation of the spinal extracellular signal-regulated kinase 5 signaling pathway contributes to morphine physical dependence in rats.

The activation of mitogen-activated protein kinases (MAPKs) has been observed in synaptic plasticity processes of learning and memory in morphine dependence. However, the role of extracellular signal-regulated protein kinase 5 (ERK5), a member of MAPKs, has not been studied yet in morphine dependence. To identify the function of ERK5 in the formation and development of morphine physical dependence, morphine withdrawal-like behavioral test and western blot technique were used in this research. Morphine was subcutaneously injected by an intermittent and escalating procedure to induce physical dependence, which was measured by withdrawal symptoms. In this study, spinal ERK5 signaling pathway was remarkably activated by chronic morphine injection and naloxone-precipitated withdrawal. Intrathecal injection of BIX02188, a novel specific inhibitor of mitogen-activated protein kinases kinase 5 (MEK5), produced a dose- and time-dependent inhibition of the activation of spinal ERK5, without affecting activation of other MAPKs. Moreover, selective attenuation of spinal p-ERK5 expression by BIX02188 could significantly relieve morphine withdrawal symptom, accompanying with the decreased phosphorylation of cAMP response-element binding protein (CREB) in the spinal cord. These findings suggested that activation of the ERK5 signaling pathway might contribute to morphine physical dependence and its specific pharmacological inhibitor BIX02188 could be a potential therapeutic choice for alleviation of morphine withdrawal symptoms in the future.

Acid solution is a suitable medium for introducing QX-314 into nociceptors through TRPV1 channels to produce sensory-specific analgesic effects.

BACKGROUND: Previous studies have demonstrated that QX-314, an intracellular sodium channel blocker, can enter into nociceptors through capsaicin-activated TRPV1 or permeation of the membrane by chemical enhancers to produce a sensory-selective blockade. However, the obvious side effects of these combinations limit the application of QX-314. A new strategy for targeting delivery of QX-314 into nociceptors needs further investigation. The aim of this study is to test whether acidic QX-314, when dissolves in acidic solution directly, can enter into nociceptors through acid-activated TRPV1 and block sodium channels from the intracellular side to produce a sensory-specific analgesic effect. METHODOLOGY/PRINCIPAL FINDINGS: Acidic solution or noradrenaline was injected intraplantarly to induce acute pain behavior in mice. A chronic constrictive injury model was performed to induce chronic neuropathic pain. A sciatic nerve blockade model was used to evaluate the sensory-specific analgesic effects of acidic QX-314. Thermal and mechanical hyperalgesia were measured by using radiant heat and electronic von Frey filaments test. Spinal Fos protein expression was determined by immunohistochemistry. The expression of p-ERK was detected by western blot assay. Whole cell clamp recording was performed to measure action potentials and total sodium current in rats DRG neurons. We found that pH 5.0 PBS solution induced behavioral hyperalgesia accompanied with the increased expression of spinal Fos protein and p-ERK. Pretreatment with pH 5.0 QX-314, and not pH 7.4 QX-314, alleviated pain behavior, inhibited the increased spinal Fos protein and p-ERK expression induced by pH 5.0 PBS or norepinephrine, blocked sodium currents and abolished the production of action potentials evoked by current injection. The above effects were prevented by TRPV1 channel inhibitor SB366791, but not by ASIC channel inhibitor amiloride. Furthermore, acidic QX-314 employed adjacent to the sciatic nerve selectively blocked the sensory but not the motor functions in naïve and CCI mice. CONCLUSIONS/SIGNIFICANCE: Acid solution is a suitable medium for introducing QX-314 into nociceptors through TRPV1 channels to produce a sensory-specific analgesic effect.