Role of macrophage autophagy in postoperative pain and inflammation in mice

BACKGROUND

Postoperative pain and inflammation are significant complications following surgery. Strategies that aim to prevent excessive inflammation without hampering natural wound-healing are required for the management of postoperative pain and inflammation. However, the knowledge of the mechanisms and target pathways involved in these processes is lacking. Recent studies have revealed that autophagy in macrophages sequesters pro-inflammatory mediators, and it is therefore being recognized as a crucial process involved in regulating inflammation. In this study, we tested the hypothesis that autophagy in macrophages plays protective roles against postoperative pain and inflammation and investigated the underlying mechanisms.

METHODS

Postoperative pain was induced by plantar incision under isoflurane anesthesia in mice lacking macrophage autophagy (Atg5flox/flox LysMCre +) and their control littermates (Atg5flox/flox). Mechanical and thermal pain sensitivity, changes in weight distribution, spontaneous locomotor activity, tissue inflammation, and body weight were assessed at baseline and 1, 3, and 7 days after surgery. Monocyte/macrophage infiltration at the surgical site and inflammatory mediator expression levels were evaluated.

RESULTS

Atg5flox/flox LysMCre + mice compared with the control mice exhibited lower mechanical and thermal pain thresholds and surgical/non-surgical hindlimb weight-bearing ratios. The augmented neurobehavioral symptoms observed in the Atg5flox/flox LysMCre + mice were associated with more severe paw inflammation, higher pro-inflammatory mediator mRNA expression, and more monocytes/macrophages at the surgical site.

CONCLUSION

The lack of macrophage autophagy augmented postoperative pain and inflammation, which were accompanied by enhanced pro-inflammatory cytokine secretion and surgical-site monocyte/macrophage infiltration. Macrophage autophagy plays a protective role in postoperative pain and inflammation and can be a novel therapeutic target.

Characterization of lipidic plaque materials at calcified atheroma: its association with calcification thickness evaluated by optical coherence tomography and near-infrared spectroscopy imaging

Introduction

The degree of calcification and its thickness have been considered to affect stent expansion, leading to an increases risk of repeat revascularization in patients receiving PCI. Pathophysiologically, accumulation of lipidic materials within vessel wall could trigger the formation of plaque calcification. Elucidating characteristics of lipidic plaque components at calcified atheroma may enable to identify phenotypes with thick calcification which less likely responds to PCI.

Purpose

This study investigated the relationship of calcification thickness with lipidic plaque materials at calcified atheroma by using OCT and near-infrared spectroscopy (NIRS) imaging.

Methods

We analyzed 52 calcified lesions (culprit/non culprit lesions=44/8) in 47 CAD patients (stable CAD/ACS=36/11) from the REASSURE-NIRS registry (NCT04864171). OCT and NIRS imaging evaluated 4-mm segment exhibiting maximum superficial calcification arc. Calcification thickness on OCT imaging, its arc on IVUS imaging, and NIRS-derived lipid arc were analyzed at every 1-mm interval cross-sectional images. In addition, yellow-calcification ratio (YCR = lipid arc/calcification arc) was calculated (Figure 1).

Results

53% of study subjects exhibited chronic kidney disease and 70% of them received a statin (averaged on-treatment LDL-C =89mg/dL). Throughout OCT and NIRS/IVUS imaging analysis of 260 cross-sectional images, the averaged calcification arc, its maximum thickness, lipid arc and YCR were 210° (167–285°), 0.78mm (0.62–0.95mm), 95° (31–169°) and 0.33 (0.09–0.59), respectively. As expected, thicker calcification more likely exhibited a greater calcification arc (r=0.30, p<0.001). Furthermore, a greater thickness of calcification was associated with smaller lipidic plaque burden, reflected by yellow arc (r=−0.36, p<0.001) and YCR (r=−0.36, p<0.001) (Figure 2). After adjusting age, gender and ACS, calcification arc (p<0.001) and YCR (p<0.001) continued to predict thicker calcification.

Conclusion

Thickening of calcification was associated with severer calcification arc, which was accompanied by the shrinkage of lipidic plaques. Our findings suggest the evaluation of lipidic plaque component as a potential tool to identify calcified atheroma harbouring thick calcification, which may cause a greater risk of stent underexpansion.

Funding Acknowledgement

Type of funding sources: None.

Propofol ameliorates ischemic brain injury by blocking TLR4 pathway in mice

Ischemic brain injury is one of the most serious perioperative complications. However, effective preventative methods have not yet been established. This study aimed to investigate whether propofol has neuroprotective effects against ischemic brain injury, with a specific focus on Toll-like receptor 4 (TLR4). Focal brain ischemia was induced via a combination of left common carotid artery occlusion and distal left middle cerebral artery coagulation in mice. Either propofol (10 mg/kg) or vehicle was intravenously injected 10 min prior to the induction of brain ischemia in wild-type and TLR4 knockout mice. Infarct volume, pro-inflammatory cytokine expression, inflammatory cell infiltration, and neurobehavioral function were assessed. Propofol administration significantly reduced infarct volume in wild-type mice (26.9 ± 2.7 vs 15.7 ± 2.0 mm³ at day 7), but not in TLR4 knockout mice. Compared with the control mice, the propofol-treated wild-type mice exhibited lower levels of IL-6 (0.57 ± 0.23 vs 1.00 ± 0.39 at 24 h), and smaller numbers of TLR4-expressing microglia in the penumbra (11.7 ± 3.1 vs 25.1 ± 4.7 cells/0.1 mm²). In conclusion, propofol administration prior to ischemic brain insult attenuated brain injury by blocking the TLR4-dependent pathway and suppressing pro-inflammatory cytokine production.

Drug-coated balloon versus drug-eluting stent following orbital atherectomy for calcified coronary artery: one-year outcomes of a retrospective cohort study

Background

Percutaneous coronary intervention (PCI) for calcified coronary artery remains challenging in the drug-eluting stent (DES) era. The effectiveness of drug-coated balloons (DCBs) and orbital atherectomy system (OAS) is unknown.

Methods

In this retrospective, single-center study, we compared the use of DCBs with second- and third-generation DESs following orbital atherectomy (OA) for calcified de novo coronary lesions. All patients underwent PCI with intravascular imaging. The primary endpoint was major cardiac event, that was a composite of cardiac death, death for unknown cause, non-fatal myocardial infarction, or target lesion revascularization at 1 year.

Results

Between June 2018 and December 2019, 107 patients with coronary lesions were enrolled in this study and divided into two groups: 23 patients in DCB group and 84 patients in DES group. The post-procedure segment percentage diameter stenosis was 23.1% (interquartile range [IQR], 17.7 to 32.5) with DCB versus 14.4% (IQR, 10.0 to 21.2) with DES (P<0.001). Overall adverse event rate for PCI procedure was low: one dissection with DES group, no persistent slow/no-flow, and no perforation with both group. The primary endpoint was not significantly different between 2 groups [DES: 6.0% (5/84), DCB: 0.0% (0/23), log-rank P=0.24].

Conclusions

In calcified coronary artery disease, using DCB following OA is as safe and effective as using DES following OA with respect to 1-year clinical outcomes.

Funding Acknowledgement

Type of funding sources: None.

Neutrophil Extracellular Traps Promote the Development of Intracranial Aneurysm Rupture

[Figure: see text].

Anesthetic management of a child with catecholaminergic polymorphic ventricular tachycardia undergoing insertion of implantable cardioverter defibrillator : a case report

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a fatal cardiac ion channelopathy that causes sudden unexpected death in the young.

Case presentation

The patient was a 3-year-old girl with CPVT. Insertion of an implantable cardioverter defibrillator (ICD) using epicardial pacing was scheduled. After premedication of rectal midazolam was given, general anesthesia was induced with midazolam, fentanyl, and rocuronium, and maintained with midazolam, fentanyl, remifentanil, and rocuronium. The operation was performed without any complications. Dexmedetomidine and fentanyl were continuously infused after the operation until she was extubated in the morning of postoperative day 1. Fatal arrhythmia due to perioperative stress did not occur.

Conclusions

We report the anesthetic management of a child with CPVT who underwent insertion of an ICD. CPVT-induced fatal arrhythmia did not occur perioperatively by carefully avoiding perioperative stress with premedication and post-operative sedation.

TLR4 (Toll-Like Receptor 4) Mediates the Development of Intracranial Aneurysm Rupture

Inflammation is emerging as a critical factor in the pathophysiology of intracranial aneurysm. TLR4 (toll-like receptor 4) contributes not only to the innate immune responses but also to the inflammatory processes associated with vascular disease. Therefore, we examined the contribution of the TLR4 pathway to the development of the rupture of intracranial aneurysm. We used a mouse model of intracranial aneurysm. TLR4 inhibition significantly reduced the development of aneurysmal rupture. In addition, the rupture rate and levels of proinflammatory cytokines were lower in TLR4 knockout mice than the control littermates. Macrophage/monocyte-specific TLR4 knockout mice had a lower rupture rate than the control littermate mice. Moreover, the deficiency of MyD88 (myeloid differentiation primary-response protein 88), a key mediator of TLR4, reduced the rupture rate. These findings suggest that the TLR4 pathway promotes the development of intracranial aneurysmal rupture by accelerating inflammation in aneurysmal walls. Inhibition of the TLR4 pathway in inflammatory cells may be a promising approach for the prevention of aneurysmal rupture and subsequent subarachnoid hemorrhage.

Amiodarone exacerbates brain injuries after hypoxic-ischemic insult in mice

Background

Sodium ion transportation plays a crucial role in the pathogenesis of hypoxic–ischemic brain injury. Amiodarone, a Vaughan-Williams class III antiarrhythmic drug, has been widely used to treat life-threatening arrhythmia and cardiac arrest worldwide. In addition to its inhibitory effects on the potassium channel, amiodarone also blocks various sodium ion transporters, including the voltage-gated sodium channel, sodium pump, and Na⁺/Ca⁺ exchanger. Considering these pharmacological profile, amiodarone may affect the influx–efflux balance of sodium ion in the hypoxic–ischemic brain. Previous studies suggest that the blockade of the voltage-gated sodium channel during hypoxic–ischemic brain injury exerts neuroprotection. On the contrary, the blockade of sodium pump or Na⁺/Ca⁺ exchanger during hypoxia–ischemia may cause further intracellular sodium accumulation and consequent osmotic cell death. From these perspectives, the effects of amiodarone on sodium ion balance on the hypoxic–ischemic brain can be both protective and detrimental depending on the clinical and pathophysiological conditions. In this study, we therefore investigated the effect of amiodarone on hypoxic–ischemic brain injury using a murine experimental model.

Results

Compared with the control group mice, mice that received amiodarone after induction of 40-min hypoxic–ischemic brain injury exhibited lower survival rates over 7 days and worse neurological function. After 25-min hypoxic–ischemic brain injury, amiodarone treated mice exhibited larger infarct volumes (16.0 ± 6.9 vs. 24.2 ± 6.8 mm³, P < 0.05) and worse neurological function. In addition, the brains harvested from the amiodarone-treated mice contained larger amounts of sodium (194.7 ± 45.1 vs. 253.5 ± 50.9 mEq/kg dry weight, P < 0.01) and water (259.3 ± 8.9 vs. 277.2 ± 12.5 mg, P < 0.01). There were no significant differences in hemodynamic parameters between groups.

Conclusions

Amiodarone exacerbated brain injuries and neurological outcomes after hypoxic–ischemic insults. Severe brain sodium accumulation and brain edema were associated with the detrimental effects of amiodarone. Amiodarone at the clinical dose can exacerbate brain injury after hypoxic–ischemic insult by affecting sodium ion transportation and facilitate intracellular sodium accumulation in the brain.

Assessment of the potential for pathogen dispersal during high-flow nasal therapy

High-flow nasal therapy is increasingly used in hospitals because of its effectiveness and patient comfort. However, pathogens in the patient's nasal and oral cavities may be dispersed by forced air. This study aimed to investigate the risk of pathogen dispersal during high-flow nasal therapy. Liquid and bacterial dispersal were assessed via in-vitro experimental set-ups using a manikin. Thickened water or fresh yeast solution mimicked saliva and nasal mucus secretions. Dispersal was limited to the proximal area of the face and nasal cannula, suggesting that high-flow nasal therapy does not increase the risk of droplet and contact infection.

Roles of Nicotine in the Development of Intracranial Aneurysm Rupture

Background and Purpose- Tobacco cigarette smoking is considered to be a strong risk factor for intracranial aneurysmal rupture. Nicotine is a major biologically active constituent of tobacco products. Nicotine's interactions with vascular cell nicotinic acetylcholine receptors containing α7 subunits (α7*-nAChR) are thought to promote local inflammation and sustained angiogenesis. In this study, using a mouse intracranial aneurysm model, we assessed potential contributions of nicotine exposure and activation of α7*-nAChR to the development of aneurysmal rupture. Methods- Intracranial aneurysms were induced by a combination of deoxycorticosterone-salt induced hypertension and a single-dose elastase injection into cerebrospinal fluid in mice. Results- Exposure to nicotine or an α7*-nAChR-selective agonist significantly increased aneurysm rupture rate. Coexposure to an α7*-nAChR antagonist abolished nicotine's deleterious effect. In addition, nicotine's promotion of aneurysm rupture was absent in smooth muscle cell-specific α7*-nAChR subunit knockout mice but not in mice lacking α7*-nAChR on endothelial cells or macrophages. Nicotine treatment increased the mRNA levels of vascular endothelial growth factor, platelet-derived growth factor-B, and inflammatory cytokines. α7*-nAChR antagonist reversed nicotine-induced upregulation of these growth factors and cytokines. Conclusions- Our findings indicate that nicotine exposure promotes aneurysmal rupture through actions on vascular smooth muscle cell α7*-nAChR.

Sudden onset pacemaker-induced diaphragmatic twitching during general anesthesia

BACKGROUND

Involuntary muscle contraction caused by extracardiac stimulation is a rare complication induced by a pacemaker. We report a case who developed sudden onset diaphragmatic contractions during general anesthesia caused by a DDD mode pacemaker.

CASE PRESENTATION

A 74-year-old woman with a permanent pacemaker was scheduled to undergo mastectomy. The pacing mode was switched from DDD to VOO intraoperatively to avoid electromagnetic interference. Immediately after returning the pacing mode to DDD after surgery, diaphragmatic contractions occurred, mimicking bucking type of movements. After switching the pacing to A-sense V-pace, the twitching ceased. Because no structural problems were noted, and the twitching disappeared after terminating atrial pacing, diaphragmatic contractions might be caused by stimulation of the right phrenic nerve located near the right appendage where the electrode was installed.

CONCLUSION

The potential risk of muscle twitching should be carefully evaluated preoperatively especially in patients with atypical position of pacemaker leads.

Removal methods of rigid stylets to minimise adverse force and tracheal tube movement: a mathematical and in-vitro analysis in manikins

This study investigated displacement of the tracheal tube caused by different methods of intubating stylet removal, using in-vitro experiments and mathematical analysis. In the first in-vitro experiment, we measured the distance travelled by the tube tip during stylet extraction. Then, we investigated the ideal technique for stylet extraction using mathematical analysis, which would cause minimal tube displacement. Then, using a training manikin, we measured the force applied to the vocal cords and stylet extraction force during tracheal intubation. When the stylet was extracted along a straight path towards the stylet end, the distance travelled by the tube tip significantly increased as the bending angle increased. Mathematical analysis revealed that the stylet should be diagonally extracted (in the sagittal plane) at an appropriate angle, rather than along a straight path towards the direction of the stylet end. In simulated tracheal intubation, extraction force and force applied to the vocal cords both significantly increased as the bending angle increased. Compared with the 'hockey stick'-shaped stylet, the arcuate-shaped stylet resulted in reduced force. Our results indicate the potential risk for vocal cord injury when using hockey stick-shaped stylets with large bending angles.

Changes of cerebral regional oxygen saturation during pneumoperitoneum and Trendelenburg position under propofol anesthesia: a prospective observational study

BACKGROUND

We evaluated the change of cerebral regional tissue oxygen saturation (rSO₂) along with the pneumoperitoneum and the Trendelenburg position. We also assessed the relationship between the change of rSO₂ and the changes of mean arterial blood pressure (MAP), heart rate (HR), arterial carbon dioxide tension (PaCO₂), arterial oxygen tension (PaO₂), or arterial oxygen saturation (SaO₂).

METHODS

Forty-one adult patients who underwent a robotic assisted endoscopic prostatic surgery under propofol and remifentanil anesthesia were involved in this study. During the surgery, a pneumoperitoneum was established using carbon dioxide. Measurements of rSO₂, MAP, HR, PaCO₂, PaO₂, and SaO₂ were performed before the pneumoperitoneum (baseline), every 5 min after the onset of pneumoperitoneum, before the Trendelenburg position. After the onset of the Trendelenburg position, rSO₂, MAP, HR were recorded at 5, 10, 20, 30, 45, and 60 min, and PaCO₂, PaO₂, and SaO₂ were measured at 10, 30, and 60 min.

RESULTS

Before the pneumoperitoneum, left and right rSO₂ were 67.9 ± 6.3% and 68.5 ± 7.0%. Ten minutes after the onset of pneumoperitoneum, significant increase in the rSO₂ was observed (left: 69.6 ± 5.9%, right: 70.6 ± 7.4%). During the Trendelenburg position, the rSO₂ increased initially and peaked at 5 min (left: 72.2 ± 6.5%, right: 73.1 ± 7.6%), then decreased. Multiple regression analysis showed that change of rSO₂ correlated with MAP and PaCO₂.

CONCLUSIONS

Pneumoperitoneum and the Trendelenburg position in robotic-assisted endoscopic prostatic surgery did not worsen cerebral oxygenation. Arterial blood pressure is the critical factor in cerebral oxygenation.

TRIAL REGISTRATION

Japan Primary Registries Network (JPRN); UMIN-CTR ID; UMIN000026227 (retrospectively registered).

Translocator protein 18kDa antagonist ameliorates stress-induced stool abnormality and abdominal pain in rodent stress models

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by abdominal pain and abnormal bowel habits, both of which are exacerbated by psychological stress. The translocator protein 18kDa (TSPO) is a marker of reactive gliosis in a number of central nervous system (CNS) diseases and responsible for many cellular functions, including neurosteroidogenesis. Although it has been reported that psychological stress disturbs neurosteroids levels, the pathophysiological relevance of TSPO in IBS is poorly understood.

METHODS

We examined the effects of a TSPO antagonist, ONO-2952, on stress-induced stool abnormality and abdominal pain in rats, and on anxiety-related behavior induced by cholecystokinin.

KEY RESULTS

Oral administration of ONO-2952 attenuated stress-induced defecation and rectal hyperalgesia in rats with an efficacy equivalent to that of a 5-HT₃ receptor antagonist. In addition, ONO-2952 suppressed cholecystokinin-induced anxiety-like behavior with an efficacy equivalent to that of psychotropic drugs. On the other hand, ONO-2952 did not affect spontaneous defecation, gastrointestinal transit, visceral nociceptive threshold, and neurosteroid production in non-stressed rats even at a dose 10 times higher than its effective dose in the stress models.

CONCLUSIONS AND INFERENCES

These results suggest that TSPO antagonism results in antistress action, and that ONO-2952 is a promising candidate for IBS without side effects associated with current treatment.

Neuroprotective effects of amiodarone in a mouse model of ischemic stroke

Background

Ion channels play a crucial role in the development of ischemic brain injury. Recent studies have reported that the blockade of various types of ion channels improves outcomes in experimental stroke models. Amiodarone, one of the most effective drugs for life-threatening arrhythmia, works as a multiple channel blocker and its characteristics cover all four Vaughan-Williams classes. Although it is known that amiodarone indirectly contributes to preventing ischemic stroke by maintaining sinus rhythm in patients with atrial fibrillation, the direct neuroprotective effect of amiodarone has not been clarified. The purpose of this study was to investigate the direct effect of amiodarone on ischemic stroke in mice.

Methods

Focal cerebral ischemia was induced via distal permanent middle cerebral artery occlusion (MCAO) in adult male mice. The amiodarone pre-treatment group received 50 mg/kg of amiodarone 1 h before MCAO; the amiodarone post-treatment groups received 50 mg/kg of amiodarone immediately after MCAO; the control group received vehicle only. In addition, the sodium channel opener veratrine and selective beta-adrenergic agonist isoprotelenol were used to elucidate the targeted pathway. Heart rate and blood pressure were monitored perioperatively. Infarct volume analysis was conducted 48 h after MCAO. The body asymmetry test and the corner test were used for neurological evaluation.

Results

Amiodarone pre-treatment and post-treatment reduced the heart rate but did not affect the blood pressure. No mice showed arrhythmia. Compared with the control group, the amiodarone pre-treatment group had smaller infarct volumes (8.9 ± 2.1% hemisphere [mean ± SD] vs. 11.2 ± 1.4%; P < 0.05) and improved functional outcomes: lower asymmetric body swing rates (52 ± 17% vs. 65 ± 18%; P < 0.05) and fewer left turns (7.1 ± 1.2 vs. 8.3 ± 1.2; P < 0.05). In contrast, amiodarone post-treatment did not improve the outcomes after MCAO. The neuroprotective effect of amiodarone pre-treatment was abolished by co-administration of veratrine but not by isoproterenol.

Conclusions

Amiodarone pre-treatment attenuated ischemic brain injury and improved functional outcomes without affecting heart rhythm and blood pressure. The present results showed that amiodarone pre-treatment has neuroprotective effects, at least in part, via blocking the sodium channels.

Abstract 147: Role of Nicotine in the Development of Intracranial Aneurysm Rupture

Background: Nicotine is one of main chemicals of tobacco smoke and promotes atherosclerosis and stroke. Tobacco smoke is considered an independent risk factor for intracranial aneurysm formation, growth, and rupture. There are mainly 5 subtypes of nicotine receptors. Roles of alpha7 nicotinic acetylcholine receptor (α7nAChR) in inflammation and vascular remodeling are diverse and context-dependent. Notably, endothelial α7nAChR is considered to mediate nicotine-induced inflammation. Activation of endothelial α7nAChR by nicotine may promote aneurysm rupture by increasing the aneurysm wall inflammation. Using a mouse model of intracranial aneurysm, we examined effects of nicotine in aneurysm rupture. Moreover we investigated potential roles of α7nAChR stimulation by nicotine in the pathophysiology of intracranial aneurysms.

Methods: Intracranial aneurysms were induced by a combination of elastase injection into the cerebrospinal fluid and deoxycorticosteron acetate-salt (DOCA-salt) hypertension in male mice. Mice were treated with (1) nicotine (5 mg/kg/day, n=25); (2) saline sc (n=22) for three weeks after aneurysm induction. To investigate the effect of α7nAChR, mice were treated with (1) saline sc + saline ip (n=11); (2) saline sc + α7nAChR antagonist (Methyllycaconitine, MLA 5mg/kg/day) ip (n=13); (3) nicotine (5 mg/kg/day, sc, 28 days) + saline ip (n=18); (4) nicotine sc + MLA ip (n=18).

Results: Nicotine alone significantly increased aneurysmal rupture compared with saline treatment (89% vs 46%, p=0.009). While α7nAChR antagonist did not affect the incidence of aneurysm or rupture rates, the α7nAChR antagonist significantly reduced the deleterious effect of nicotine as indicated by the reduction of the rupture rates (41% vs 100%: nicotine sc + MLA ip group vs nicotine sc + saline ip group, p=0.027).

Conclusion: Our data indicate the promotion of aneurysm rupture by nicotine may be mediated by its stimulation of alpha7nAChR.

Abstract 197: Roles of Neutrophil Extracellular Trap in the Rupture of Intracranial Aneurysm

Introduction: Neutrophil extracellular traps (NETs) are originally described as proinflammatory, antimicrobial structures consisting of extracellular chromatin decorated with granular and cytoplasmic proteins. The formation of NETs requires peptidylarginine deiminase (PAD) 4. Recent studies revealed that NETs can play an important role in promoting inflammation in vascular diseases. Inflammation is emerging as a key component of the pathophysiology of intracranial aneurysm. In both human and mouse studies, activated neutrophils were shown to be associated with formation and rupture of intracranial aneurysms. Therefore, we hypothesized that the formation of NETs by PAD4 promotes the development of aneurysm rupture. We tested this hypothesis utilizing both pharmacological and genetic approaches in mice.

Methods: We used 8- to 10-week-old male C57BL/6J mice, global PAD4 knock out (KO) and granulocyte-specific PAD4 KO mice. Aneurysm was induced by a combination of elastase injection and hypertension as we previously describes. We used deoxycorticosterone acetate (DOCA)-salt hypertension. A single dose of elastase was injected into the cerebrospinal fluid using a stereotaxic approach.

Results: Cl-amidine, an inhibitor for PAD4, significantly decreased the rupture rates (92 vs 36%, P < 0.01). At the same time, Cl-amidine decreased the number of neutrophils and the formation of NETs analyzed by Ly-6G staining and citrullinated histone H3 staining, respectively. In the inhibitor treated mice, the messenger ribonucleic acid (RNA) level of ICAM-1, MCP-1 and TNFα in the cerebral arteries were lower than that of vehicle control treated mice. Furthermore, the rupture rates were decreased in the global PAD4 KO mice and the granulocyte-specific PAD4 KO mice than in the corresponding wild type mice groups. Finally, inhibition of the formation of NETs by DNase treatment also reduced the rupture rates.

Conclusions: Our data indicate that the formation of NETs by granulocyte PAD4 promotes the development of aneurysm rupture. NETs may be represented a potential therapeutic target for the prevention of aneurysm rupture.

[A case of severe hypotension caused by external cardiac compression by tumor and doctor's hand in a patient with mediastinal tumor]

There are several causes of hypotension during anesthesia. We report a case of severe hypotension caused by external cardiac compression. A 72-year-old man was scheduled for resection of mediastinal tumor under general anesthesia. He had undergone mediastinal tumor resection four times uneventfully. Anesthesia was induced and maintained with target controlled infusion of propofol and continuous infusion of remifentanil. Tracheal intubation was facilitated with rocuronium. Massive bleeding and severe hypotension developed during the operation. Blood transfusion, cryoprecipitate, fresh frozen plasma, and percutaneous cardiopulmonary support were commenced. However, hemorrhage was not the only cause of hypotension. The transesophageal echocardiography revealed external cardiac compression by tumor and doctor's hand. Transesophageal echocardiography was useful for verifying the causes of hypotension. It is necessary to evaluate the causes of hypotension during the operation, because a certain number of problems may exist.

[Anesthetic management for laparoscopic adrenalectomy in a pregnant patient with Cushing's syndrome]

Cushing's syndrome is extremely rare during pregnancy, because it often causes amenorrhea and infertility. We experienced a case of Cushing's syndrome in the 23rd week of pregnancy receiving laparoscopic surgery. It was difficult to control the blood pressure and heart rate, but we succeeded in the safe management of both mother and fetus.