Hypothermia Attenuates Neurotoxic Microglial Activation via TRPV4.

Therapeutic hypothermia (TH) provides neuroprotection. However, the cellular mechanisms underlying the neuroprotective effects of TH are not fully elucidated. Regulation of microglial activation has the potential to treat a variety of nervous system diseases. Transient receptor potential vanilloid 4 (TRPV4), a nonselective cation channel, is activated by temperature stimulus at 27-35 °C. Although it is speculated that TRPV4 is associated with the neuroprotective mechanisms of TH, the role of TRPV4 in the neuroprotective effects of TH is not well understood. In the present study, we investigated whether hypothermia attenuates microglial activation via TRPV4 channels. Cultured microglia were incubated under normothermic (37 °C) or hypothermic (33.5 °C) conditions following lipopolysaccharide (LPS) stimulation. Hypothermic conditions suppressed the expression of pro-inflammatory cytokines, inducible nitric oxide synthase, and the number of phagocytic microglia. AMP-activated protein kinase (AMPK)-NF-κB signaling was inhibited under hypothermic conditions. Furthermore, hypothermia reduced neuronal damage induced by LPS-treated microglial cells. Treatment with TRPV4 antagonist in normothermic culture replicated the suppressive effects of hypothermia on microglial activation and microglia-induced neuronal damage. In contrast, treatment with a TRPV4 agonist in hypothermic culture reversed the suppressive effect of hypothermia. These findings suggest that TH suppresses microglial activation and microglia-induced neuronal damage via the TRPV4-AMPK-NF-κB pathway. Although more validation is needed to consider differences according to age, sex, and specific central nervous system regions, our findings may offer a novel therapeutic approach to complement TH.

Leucine-rich alpha-2-glycoprotein 1 affects bone destruction via IL-6 in mouse periodontitis model.

OBJECTIVE: To investigate the production of leucine-rich α-2-glycoprotein-1 (LRG1) in periodontitis patients and its effectiveness as a new diagnostic marker for periodontitis. SUBJECTS AND METHODS: In vitro experiments were conducted to analyze LRG1 mRNA expression in human gingival epithelial cells and fibroblasts via quantitative real-time PCR. In vivo experiments were conducted to analyze LRG1 localization in periodontitis patients. The correlation between the serum LRG1 levels and alveolar bone resorption in the mouse periodontitis model was also investigated. RESULTS: A positive correlation existed between the periodontal inflamed surface area and serum LRG1 levels (Spearman's rank correlation coefficient: 0.60). LRG1 mRNA expression in human gingival epithelial cells and fibroblasts was upregulated by Porphyromonas gingivalis stimulation or tumor necrosis factor-α stimulation. Interleukin-6 in human gingival epithelial cells and fibroblasts induced the production of LRG1 and transforming growth factor-ß. LRG1 levels in the periodontal tissue and serum in the periodontitis model were higher than those in control mice. LRG1 local administration resulted in alveolar bone resorption, whereas the administration of interleukin-6R antibody inhibited bone resorption. CONCLUSIONS: LRG1 levels in serum and periodontal tissue are upregulated in periodontitis and are implicated in periodontal tissue destruction through interleukin-6 production.

Periapical lesion following Cnm-positive Streptococcus mutans pulp infection worsens cerebral hemorrhage onset in an SHRSP rat model.

Cerebral hemorrhage severely affects the daily life of affected individuals. Streptococcus mutans and its adhesion factor Cnm increase the adverse effects of cerebral hemorrhages. However, the mechanism by which Cnm-positive bacteria migrate from apical lesions to cerebral hemorrhage sites is unclear. Therefore, we established an S. mutans-infected apical lesion in a rat model of hypertension and investigated the neurological symptoms associated with cerebral hemorrhage. Eighteen 12-week-old stroke-prone spontaneously hypertensive rats were randomly divided into three groups, i.e. the no infection (control), dental infection with S. mutans KSM153 wild type (Cnm positive), and KSM153 Δcnm groups. Immunofluorescent staining was performed to visualize S. mutans protein. Serum interleukin-1ß levels were measured. The adhesion of S. mutans to the extracellular matrix and human fibroblast cells was also analyzed. Serum antibody titers against S. mutans were comparable between Cnm positive and knockout mutants. However, 3-10 days post-infection, neurological symptom scores and cerebral hemorrhage scores were higher in Cnm-positive rats than in knockout mutants. The localization of S. mutans-derived protein was observed in the vicinity of disrupted blood vessels. Serum interleukin-1ß levels significantly increased post-KSM153 WT infection. Cnm-positive S. mutans clinical isolates showed increased adhesion to the extracellular matrix, human dental pulp cells, and human umbilical vein endothelial cells compared with the Cnm-negative S. mutans isolates. In conclusion, Cnm-positive bacteria colonize the apical lesion site using the extracellular matrix as a foothold and affect cerebral hemorrhage via the bloodstream.

Hypothermia Attenuates Neuronal Damage via Inhibition of Microglial Activation, Including Suppression of Microglial Cytokine Production and Phagocytosis.

Although therapeutic hypothermia (TH) provides neuroprotection, the cellular mechanism underlying the neuroprotective effect of TH has not yet been fully elucidated. In the present study, we investigated the effect of TH on microglial activation to determine whether hypothermia attenuates neuronal damage via microglial activation. After lipopolysaccharide (LPS) stimulation, BV-2 microglia cells were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions. Under hypothermic conditions, expression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) was suppressed. In addition, phagocytosis of latex beads was significantly suppressed in BV-2 cells under hypothermic conditions. Moreover, nuclear factor-κB signaling was inhibited under hypothermic conditions. Finally, neuronal damage was attenuated following LPS stimulation in neurons co-cultured with BV-2 cells under hypothermic conditions. In conclusion, hypothermia attenuates neuronal damage via inhibition of microglial activation, including microglial iNOS and pro-inflammatory cytokine expression and phagocytic activity. Investigating the mechanism of microglial activation regulation under hypothermic conditions could contribute to the development of novel neuroprotective therapies.

Efficacy and safety of colorectal endoscopic submucosal dissection in patients with sarcopenia.

BACKGROUND: Endoscopic submucosal dissection (ESD) for early-stage colorectal cancer (CRC) has become a common and useful treatment. Although sarcopenia has been identified as an independent risk factor for complications after surgery for CRC, whether sarcopenia is also an independent risk factor for complications after colorectal ESD remains to be clarified. The aim of this study was to compare the outcomes of colorectal ESD in patients with and those without sarcopenia. METHODS: This is a retrospective cohort study. A total of 334 patients underwent colorectal ESD for 361 neoplasms at Hiratsuka City Hospital from March 2012 to October 2018. The neoplasms were divided into two groups depending on the presence or absence of sarcopenia in the patients. RESULTS: Overall, 334 patients underwent colorectal ESD for 361 neoplasms during the study period. We excluded 90 patients (90 neoplasms), and 244 patients (277 neoplasms) were included in the final analysis (134 from the sarcopenia group, 137 from the non-sarcopenia group). The en-bloc resection rate was high and was not significantly different between the sarcopenia group [126/134 (94.1%)] and the non-sarcopenia group [133/137 (97.1%)], P = 0.1778). The rate of perforation and the rate of delayed bleeding were not significantly different between the sarcopenia group and the non-sarcopenia group [6/134 (4.5%) vs. 9/137 (6.6%), P = 0.314, 4/134 (3%) vs. 6/137 (4.4%), P = 0.3885, respectively]. CONCLUSIONS: The presence of sarcopenia did not influence the rate of complications after ESD. Colorectal ESD is safe and effective even in patients with sarcopenia. Prospective multicenter studies are necessary to confirm our results.

Prolonged astrocyte-derived erythropoietin expression attenuates neuronal damage under hypothermic conditions.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) has a high morbidity rate and involves severe neurologic deficits, including cerebral palsy. Therapeutic hypothermia (TH) has been shown to decrease the mortality rate and provide neuroprotection in infants with HIE. However, death and disability rates in HIE infants treated with TH remain high. Although the cellular mechanism of the neuroprotective effect of TH remains unclear, astrocytic erythropoietin (EPO) is known to be a key mediator of neuroprotection under hypoxic conditions. In the present study, we investigated the hypothermia effect on EPO expression in astrocytes and determined whether hypothermia attenuates neuronal damage via EPO signaling. METHODS: Astrocytes derived from rat cerebral cortex were cultured under oxygen/glucose deprivation (OGD). The expression of EPO and hypoxia-inducible factor (HIF), a transcription factor of EPO, was assessed. After OGD, astrocytes were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions, and then EPO and HIF expression was assessed. After OGD, rat cortical neurons were cultured in astrocyte-conditioned medium (ACM) derived from the hypothermic group, and neuronal apoptosis was evaluated. RESULTS: OGD induced EPO mRNA and protein expression, although at lower levels than hypoxia alone. HIF-1α and HIF-2α protein expression increased under hypoxia alone and OGD, although OGD increased HIF-2α protein expression less than hypoxia alone. EPO gene and protein expression after OGD was significantly higher under hypothermia. Moreover, expression of HIF-1α and HIF-2α protein was enhanced under hypothermia. In the presence of ACM derived from hypothermic astrocytes following OGD, the number of cleaved caspase 3 and TdT-mediated dUTP nick-end labeling-positive apoptotic neurons was lower than in the presence of ACM from normothermic astrocytes following OGD. Blockade of EPO signaling using anti-EPO neutralization antibody attenuated the anti-apoptotic effect of ACM derived from hypothermic astrocytes following OGD. CONCLUSIONS: Hypothermia after OGD stabilized HIF-EPO signaling in astrocytes, and upregulated EPO expression could suppress neuronal apoptosis. Investigating the neuroprotective effect of EPO from astrocytes under hypothermic conditions may contribute to the development of novel neuroprotection-based therapies for HIE.

Could nanotechnology make vitamin E therapeutically effective?

Vitamin E (VitE) has important antioxidant and anti-inflammatory effects and is necessary for normal physiological function. α-Tocopherol (α-T), the predominant form of VitE in human tissues, has been extensively studied. Other VitE forms, particularly γ-tocopherol (γ-T), are also potent bioactive molecules. The effects are complex, involving both reactive oxygen and nitrogen species, but trials of VitE have been generally negative. We propose that a nanoparticle approach to delivery of VitE might provide effective delivery and therapeutic effect.

Inflammatory cytokine tumor necrosis factor α suppresses neuroprotective endogenous erythropoietin from astrocytes mediated by hypoxia-inducible factor-2α.

Interest in erythropoietin (EPO) as a neuroprotective mediator has grown since it was found that systemically administered EPO is protective in several animal models of disease. However, given that the blood-brain barrier limits EPO entry into the brain, alternative approaches that induce endogenous EPO production in the brain may be more effective clinically and associated with fewer untoward side-effects. Astrocytes are the main source of EPO in the central nervous system. In the present study we investigated the effect of the inflammatory cytokine tumor necrosis factor α (TNFα) on hypoxia-induced upregulation of EPO in rat brain. Hypoxia significantly increased EPO mRNA expression in the brain and kidney, and this increase was suppressed by TNFα in vivo. In cultured astrocytes exposed to hypoxic conditions for 6 and 12 h, TNFα suppressed the hypoxia-induced increase in EPO mRNA expression in a concentration-dependent manner. TNFα inhibition of hypoxia-induced EPO expression was mediated primarily by hypoxia-inducible factor (HIF)-2α rather than HIF-1α. The effects of TNFα in reducing hypoxia-induced upregulation of EPO mRNA expression probably involve destabilization of HIF-2α, which is regulated by the nuclear factor (NF)-κB signaling pathway. TNFα treatment attenuated the protective effects of astrocytes on neurons under hypoxic conditions via EPO signaling. The effective blockade of TNFα signaling may contribute to the maintenance of the neuroprotective effects of EPO even under hypoxic conditions with an inflammatory response.

Using miglitol at 30 min before meal is effective in hyperinsulinemic hypoglycemia after a total gastrectomy.

A 45-year-old woman who had undergone total gastrectomy for gastric cancer presented with a history of postprandial hypoglycemic episodes with loss of consciousness after meals. Laboratory findings revealed marked hyperinsulinemia and hypoglycemia after a meal. We first treated the patient with octreotide; however, she was unable to continue the treatment because of adverse effects of the drug, such as nausea and headache. Diazoxide was used next for preventing hyperinsulinemia; however, this was not effective for suppressing the postprandial insulin secretion. Since hypoglycemia following gastrectomy is thought to be caused by rapid delivery of nutrients into the duodenum, we performed a meal tolerance test while varying the timing of administration of miglitol in relation to the meal. Miglitol was administered 30 min before, just before, or both 30 min and just before a meal. In the case of administration just before a meal, insulin secretion was suppressed, although hypoglycemia was not prevented. Administration of the drug 30 min before a meal prevented postprandial hypoglycemia by slowing the increase of the blood glucose and serum insulin levels following the meal to a greater degree than administration just before a meal. Miglitol administration both 30 min and just before a meal caused an even smoother increase in blood glucose and serum insulin levels following the meal. In this report, we propose a new therapeutic approach for reactive hypoglycemia after gastrectomy, namely, administration of miglitol 30 min before meals.

Development and Validation of a Prediction Model for Acute Hypotensive Events in Intensive Care Unit Patients.

Background: Persistent hypotension in the intensive care unit (ICU) is associated with increased mortality. Predicting acute hypotensive events can lead to timely intervention. We aimed to develop a prediction model of acute hypotensive events in patients admitted to the ICU. Methods: We included adult patients admitted to the Nagoya City University (NCU) Hospital ICU between January 2018 and December 2021 for model training and internal validation. The MIMIC-III database was used for external validation. A hypotensive event was defined as a mean arterial pressure < 60 mmHg for at least 5 min in 10 min. The input features were age, sex, and time-series data for vital signs. We compared the area under the receiver-operating characteristic curve (AUROC) of three machine-learning algorithms: logistic regression, the light gradient boosting machine (LightGBM), and long short-term memory (LSTM). Results: Acute hypotensive events were found in 1325/1777 (74.6%) and 2691/5266 (51.1%) of admissions in the NCU and MIMIC-III cohorts, respectively. In the internal validation, the LightGBM model had the highest AUROC (0.835), followed by the LSTM (AUROC 0.834) and logistic regression (AUROC 0.821) models. Applying only blood pressure-related features, the LSTM model achieved the highest AUROC (0.843) and consistently showed similar results in external and internal validation. Conclusions: The LSTM model using only blood pressure-related features had the highest AUROC with comparable performance in external validation.

A Case of Multiple Brain Tuberculomas in the Subarachnoid Cisterns: Recognition of Radiological Characteristics Regarding the Development of Paradoxical Response during Antituberculosis Treatment.

Brain tuberculoma and its occurrence within the subarachnoid cisterns is rare in Japan. Serological and cerebrospinal fluid (CSF) examinations and imaging findings lack specificity; thus, preoperative diagnosis is often challenging. This report presents the case of a 70-year-old woman admitted to our hospital with a one-month history of low-grade fever and altered mental status. Based on the CSF analysis and her history of latent tuberculosis infection seven years ago, she was strongly suspected of suffering from tuberculous meningitis (TBM). Consequently, the patient was enrolled in a clinical trial for antituberculosis treatment (ATT). CSF soluble interleukin-2 receptor level decreased from 2,926 U/mL on day 1 to 225 U/mL 42 days after initiating ATT. Her condition improved after five weeks; however, contrast-enhanced T1-weighted magnetic resonance imaging (MRI) revealed multiple enhanced lesions within the basal subarachnoid cisterns 25 days after admission. As the number and size of these lesions increased, a biopsy confirmed brain tuberculoma diagnosis, and the treatment was continued. In conclusion, when intracisternal scattered mass lesions are identified during TBM treatment, we should consider the possibility of tuberculoma developments arising from a paradoxical response (PR) during the treatment. Serial MRIs are crucial in monitoring PR development in cisternal tuberculomas, an extension of severe TBM. Finally, a PR can be effectively managed by continuing ATT with adjunctive corticosteroids.

Malposition of a pulmonary artery catheter in the left ventricle: a case report.

BACKGROUND: Placement of pulmonary artery catheters may be associated with a variety of complications. We present a case where a pulmonary artery catheter was accidentally advanced into the left ventricle by perforating the intraventricular septum. CASE PRESENTATION: A 73-year-old woman underwent mitral valve dysfunction. A pulmonary artery catheter could not pass the tricuspid valve under general anesthesia, which was manually advanced via the right ventricle during surgery. After valve replacement, systolic pulmonary artery pressure was higher than radial arterial blood pressure. Transesophageal echocardiography (TEE) revealed the tip of the catheter in the left ventricle. The catheter was withdrawn and then advanced to the pulmonary artery under monitoring of TEE. Transseptal shunt flow gradually decreased and finally disappeared. The surgery was completed without additional procedures. CONCLUSIONS: Although ventricular septal perforation is rare, it should be recognized as a potential complication of pulmonary artery catheter insertion.

Incidence and factors associated with newly implemented do-not-attempt-resuscitation orders among deteriorating patients after rapid response system activation: A retrospective observational study using a Japanese multicenter database.

Aim: The rapid response system (RRS) was initially aimed to improve patient outcomes. Recently, some studies have implicated that RRS might facilitate do-not-attempt-resuscitation (DNAR) orders among patients, their families, and healthcare providers. This study aimed to examine the incidence and factors independently associated with DNAR orders newly implemented after RRS activation among deteriorating patients. Methods: This observational study assessed patients who required RRS activation between 2012 and 2021 in Japan. We investigated patients' characteristics and the incidence of new DNAR orders after RRS activation. Furthermore, we used multivariable hierarchical logistic regression models to explore independent predictors of new DNAR orders. Results: We identified 7904 patients (median age, 72 years; 59% male) who required RRS activation at 29 facilities. Of the 7066 patients without pre-existing DNAR orders before RRS activation, 394 (5.6%) had new DNAR orders. Multivariable hierarchical logistic regression analyses revealed that new DNAR orders were associated with age category (adjusted odds ratio [aOR], 1.56; 95% confidence interval, 1.12-2.17 [65-74 years old reference to 20-64 years old], aOR, 2.56; 1.92-3.42 [75-89 years old], and aOR, 6.58; 4.17-10.4 [90 years old]), malignancy (aOR, 1.82; 1.42-2.32), postoperative status (aOR, 0.45; 0.30-0.71), and National Early Warning Score 2 (aOR, 1.07; 1.02-1.12 [per 1 score]). Conclusion: The incidence of new DNAR orders was one in 18 patients after RRS activation. The factors associated with new DNAR orders were age, malignancy, postoperative status, and National Early Warning Score 2.

Peripheral neuropathy in the pre-diabetic state of the type 2 diabetes mouse model (TSOD mice) involves TRPV1 expression in dorsal root ganglions.

Peripheral neuropathy, which is a complication of diabetes mellitus (DM), is thought to occur in the pre-DM state, being known as impaired glucose tolerance (IGT) neuropathy, although its pathogenesis is unknown. Since it is reversible, an effective treatment at the pre-DM stage could stop the progression of peripheral neuropathy and improve patients' quality of life and reduce medical costs. We investigated the hypersensitivity to mechanical and thermal stimuli during the pre-DM state in Tsumura Suzuki Obese Diabetes (TSOD) mice, a type 2 DM mouse model. The expression pattern of the Transient Receptor Potential Vanilloid 1 (TRPV1)-positive cells in the dorsal root ganglia (DRG) was examined in TSOD mice, which showed a pre-DM state at 5-12 weeks of age and decreased mechanical and thermal nociceptive thresholds. Additionally, the size of TRPV1-positive cells in TSOD mice increased compared with that in non-diabetic controls (Tsumura Suzuki Non-Obesity; TSNO). Furthermore, the expression of TRPV1 on myelinated nerve fibers (neurofilament heavy-positive cells) had significantly increased. Thus, TSOD mice in the pre-DM state at 5-12 weeks of age could be a useful animal model of IGT neuropathy. We also hypothesized that the development of IGT neuropathy may involve a switch in TRPV1 expression from small, unmyelinated neurons to large, myelinated neurons in the DRG.

Anti-Inflammatory Effects of Geniposidic Acid on Porphyromonas gingivalis-Induced Periodontitis in Mice.

Periodontal disease is predominantly caused by the pathogenic bacterium Porphyromonas gingivalis that produces inflammation-inducing factors in the host. Eucommia ulmoides is a plant native to China that has been reported to reduce blood pressure, promote weight loss, and exhibit anti-inflammatory effects. Geniposidic acid (GPA) is the major component of E. ulmoides. Herein, we investigated the effects of GPA on P. gingivalis-induced periodontitis by measuring the inflammatory responses in human gingival epithelial cells (HGECs) after P. gingivalis stimulation and GPA addition in a P. gingivalis-induced periodontitis mouse model. We found that GPA addition suppressed interleukin (IL)-6 mRNA induction (33.8% suppression), IL-6 production (69.2% suppression), toll-like receptor (TLR) 2 induction, and mitogen-activated protein kinase (MAPK) phosphorylation in HGECs stimulated by P. gingivalis. Inoculation of mice with GPA inhibited P. gingivalis-induced alveolar bone resorption (25.6% suppression) by suppressing IL-6 and TLR2 production in the serum and gingiva. GPA suppressed osteoclast differentiation of bone marrow cells induced by M-CSF and sRANKL in mice (56.7% suppression). GPA also suppressed the mRNA expression of OSCAR, NFATc1, c-Fos, cathepsin K, and DC-STAMP. In summary, GPA exerts an anti-inflammatory effect on periodontal tissue and may be effective in preventing periodontal disease.

Ruptured Basilar Artery Perforator Aneurysm: A Case Report and Review of the Literature.

Basilar artery perforator aneurysms (BAPAs) are a rare cause of subarachnoid hemorrhage (SAH), and the natural history is still unknown. Herein, we report a case of ruptured BAPA that appeared during the observation period and then spontaneously disappeared; we have also conducted a review of the literature and performed an analysis based on the type of management. This case of BAPA had a unique course, and our observations may help establish a treatment strategy. A 60-year-old man presented with acute diffuse SAH, World Federation of Neurosurgical Societies (WFNS) Grade II and Fisher Grade 3. Initial three-dimensional digital subtraction angiography (DSA) did not show the source of the hemorrhage. DSA performed on day 39 showed a BAPA with a diameter of 3 mm at the posterior surface of the upper third of the basilar artery. Conservative treatment was chosen. DSA performed on day 64 showed complete resolution of the aneurysm. BAPAs are likely pseudoaneurysms, and not saccular aneurysms, caused due to dissection of basilar perforator arteries. BAPAs are often not recognized on initial imaging, and hence, it is necessary to repeat the DSA examination. Considering the relatively high rate of spontaneous resolution, we chose conservative management. When BAPAs enlarge or do not disappear after conservative treatment, additional therapy such as multiple stents should be considered.

Subthalamic nucleus deep brain stimulation for camptocormia associated with Parkinson's disease.

Camptocormia becomes increasingly recognized as a disabling symptom associated with Parkinson's disease (PD). We here report six patients with advanced PD in whom continuous bilateral stimulation of the subthalamic nucleus produced substantial (mean 78% +/- 9.1% of the thoracolumbar angle) improvement of camptocormia along with other motor symptoms.

Severe hyponatremia occurring after surgical stress in a patient with mitochondrial disease.

A 53-year-old man with mitochondrial disease underwent gastrectomy because of gastric cancer. Three days after the surgery, he developed severe hyponatremia (Na, 106 mmol l(-1)) together with hypovolemic shock and lactic acidosis. Despite the hyponatremia, his urine sodium concentration was high, suggesting renal salt wasting. Although mitochondrial diseases are not common and hyponatremia in patients with these diseases is not well known, clinicians should pay close attention to serum sodium levels and maintain them properly.