Effect of early serum phosphate disorder on in-hospital and 28-day mortality in sepsis patients: a retrospective study based on MIMIC-IV database.

BACKGROUND: This study aims to assess the influence of early serum phosphate fluctuation on the short-term prognosis of sepsis patients. METHODS: This retrospective study used the Medical Information Mart for Intensive Care IV database to analyze serum phosphate levels in sepsis patients within 3 days of ICU admission. According to the absolute value of delta serum phosphate (the maximum value minus the minimum value of serum phosphorus measured within three days), the patients were divided into four groups, 0-1.3, 1.4-2.0, 2.1-3.1, and ≥ 3.2 mg/dl. Meanwhile, the direction of delta serum phosphate was compared. With the serum phosphate change group of 0-1.3 mg/dl as the reference group, the relationship between delta serum phosphate and in-hospital mortality and 28-day mortality was analyzed by multivariate Logistics regression analysis. RESULTS: The study involved 1375 sepsis patients. Serum phosphate changes (0-1.3, 1.4-2.0, 2.1-3.1, and ≥ 3.2 mg/dl) correlated with in-hospital and 28-day mortality variations (p = 0.005, p = 0.008). Much higher serum phosphate fluctuation elevated in-hospital and 28-day mortality. Compared to the 0-1.3 mg/dl change group, adjusted odds ratios (OR) in other groups for in-hospital mortality were 1.25 (0.86-1.81), 1.28 (0.88-1.86), and 1.63 (1.10-2.43), and for 28-day mortality were 1.21 (0.86-1.72), 1.10 (0.77-1.57), and 1.49 (1.03-2.19). Under the trend of increasing serum phosphate, the ORs of in-hospital mortality and 28-day mortality in ≥ 3.2 mg/dl group were 2.52 and 2.01, respectively. CONCLUSION: In conclude, the delta serum phosphate ≥ 3.2 mg/dl was associated with in-hospital mortality and 28-day mortality in patients with sepsis.

Gut microbiota composition and changes in patients with sepsis: potential markers for predicting survival.

BACKGROUND: Sepsis can cause immune dysregulation and multiple organ failure in patients and eventually lead to death. The gut microbiota has demonstrated its precise therapeutic potential in the treatment of various diseases. This study aimed to discuss the structural changes of the gut microbiota in patients with sepsis and to analyze the differences in the gut microbiota of patients with different prognoses. METHODS: We conducted a multicenter study in which rectal swab specimens were collected on the first and third days of sepsis diagnosis. A total of 70 specimens were collected, and gut microbiota information was obtained by 16S rRNA analysis. RESULTS: The relative abundance of Enterococcus decreased in rectal swab specimens during the first three days of diagnosis in patients with sepsis, while the relative abundance of inflammation-associated Bacillus species such as Escherichia coli, Enterobacteriaceae, and Bacteroidetes increased. By comparing the differences in the flora of the survival group and the death group, we found that the abundance of Veillonella and Ruminococcus in the death group showed an increasing trend (p < 0.05), while the abundance of Prevotella_6 and Prevotella_sp_S4_BM14 was increased in surviving patients (p < 0.05). CONCLUSIONS: The Firmicutes/Bacteroidetes ratio, reflecting overall gut microbial composition, was significantly lower on day three of sepsis diagnosis. Changes in the abundance of specific gut microbiota may serve as prognostic markers in patients with sepsis.

Combined metabolomic and proteomic analysis of sepsis related acute liver injury and its pathogenesis research.

BACKGROUND: Sepsis-induced acute liver injury is common in patients in intensive care units. However, the exact mechanism of this condition remains unclear. The purpose of this study was to investigate the roles and mechanisms of proteins and metabolites in the liver tissue of mice after sepsis and elucidate the molecular biological mechanisms of sepsis-related liver injury. METHODS: First, a lipopolysaccharide (LPS)-induced sepsis mouse model was established. Then, according to alanine aminotransferase (ALT) and aspartate aminotransferase (AST) detection in mouse serum and liver histopathological examination (HE) staining, the septic mice were divided into two groups: acute liver injury after sepsis and nonacute liver injury after sepsis. Metabolomics and proteomic analyses were performed on the liver tissues of the two groups of mice to identify significantly different metabolites and proteins. The metabolomics and proteomics results were further analysed to identify the biological indicators and pathogenesis related to the occurrence and development of sepsis-related acute liver injury at the protein and metabolite levels. RESULTS: A total of 14 differentially expressed proteins and 46 differentially expressed metabolites were identified. Recombinant Erythrocyte Membrane Protein Band 4.2 (Epb42) and adenosine diphosphate (ADP) may be the key proteins and metabolites responsible for sepsis-related acute liver injury, according to the correlation analysis of proteomics and metabolomics. The expression of the differential protein Epb42 was further verified by western blot (WB) detection. CONCLUSIONS: Our study suggests that the differential protein Epb42 may be key proteins causing sepsis-associated acute liver injury, providing new and valuable information on the possible mechanism of sepsis-associated acute liver injury.

Causal relationship between gut Prevotellaceae and risk of sepsis: a two-sample Mendelian randomization and clinical retrospective study in the framework of predictive, preventive, and personalized medicine.

Objective: Gut microbiota is closely related to sepsis. Recent studies have suggested that Prevotellaceae could be associated with intestinal inflammation; however, the causal relationship between Prevotellaceae and sepsis remains uncertain. From the perspective of predictive, preventive, and personalized medicine (PPPM), exploring the causal relationship between gut Prevotellaceae and sepsis could provide opportunity for targeted prevention and personalized treatment. Methods: The genome-wide association study (GWAS) summary-level data of Prevotellaceae (N = 7738) and sepsis were obtained from the Dutch Microbiome Project and the UK Biobank (sepsis, 1380 cases; 429,985 controls). MR analysis was conducted to estimate the associations between Prevotellaceae and sepsis risk. The 16S rRNA sequencing analysis was conducted to calculate the relative abundance of Prevotellaceae in sepsis patients to explore the relationship between Prevotellaceae relative abundance and the 28-day mortality. Results: Genetic liability to f__Prevotellaceae (OR, 1.91; CI, 1.35-2.71; p = 0.0003) was associated with a high risk of sepsis with inverse-variance weighted (IVW). The median Prevotellaceae relative abundance in non-survivors was significantly higher than in survivors (2.34% vs 0.17%, p < 0.001). Multivariate analysis confirmed that Prevotellaceae relative abundance (OR, 1.10; CI, 1.03-1.22; p = 0.027) was an independent factor of 28-day mortality in sepsis patients. ROC curve analysis indicated that Prevotellaceae relative abundance (AUC: 0.787, 95% CI: 0.671-0.902, p = 0.0003) could predict the prognosis of sepsis patients. Conclusion: Our results revealed that Prevotellaceae was causally associated with sepsis and affected the prognosis of sepsis patients. These findings may provide insights to clinicians on developing improved sepsis PPPM strategies. Supplementary Information: The online version contains supplementary material available at 10.1007/s13167-023-00340-6.

ß3GNT9 as a prognostic biomarker in glioblastoma and its association with glioblastoma immune infiltration, migration and invasion.

Background: Studies have shown that the immune infiltration of tumor microenvironment is related to the prognosis of glioblastoma, which is characterized by high heterogeneity, high recurrence rate and low survival rate. To unravel the role of ß1,3-N-acetylglucosaminyltransferase-9 (ß3GNT9) in the progression of glioblastoma, this study identifies the value of ß3GNT9 as a prognostic biomarker in glioblastoma, and investigates the relationship between ß3GNT9 expression and glioblastoma immune infiltration, migration and invasion. Methods: ß3GNT9 expression in glioblastoma was analyzed using the GEPIA database. The clinical features of glioblastoma were screened out from the TCGA database. The relationship between ß3GNT9 expression and clinical features was analyzed. The relationship between ß3GNT9 and the prognosis of glioblastoma was evaluated through univariate and multivariate COX regression analyses, and the survival analysis was conducted using the Kaplan-Meier method. GSEA was employed to predict the signaling pathway of ß3GNT9 in glioblastoma. The correlation between ß3GNT9 and tumor immune infiltration was analyzed using the related modules of CIBERSORT and TIMER. A172, U87MG and U251 cell lines were selected to verify ß3GNT9 expression in vitro. The effects of ß3GNT9 on the migration and invasion of glioblastoma were investigated through cell scratch and invasion assays. Results: ß3GNT9 expression in glioblastoma group was significantly higher than that in normal brain tissue group (P<0.05). The overall survival rate in high ß3GNT9 expression group was significantly lower than that in low ß3GNT9 expression group (P<0.05). Regression analyses suggested that ß3GNT9, involved primarily in glucosamine degradation and extracellular matrix receptor interaction, could be an independent prognostic factor for glioblastoma. CIBERSORT and GEPIA database analyses showed that ß3GNT9 was correlated with tumor infiltrating immune cells such as T follicular helper cells, activating natural killer cells, monocytes, macrophages, and eosinophils, thus affecting the immune microenvironment of glioblastoma. Cell experiments confirmed that ß3GNT9 was highly expressed in A172, U87MG and U251 cell lines (P<0.05), and promoted the migration and invasion of glioblastoma (P<0.05). Conclusion: The increased expression of ß3GNT9 in glioblastoma can affect the immune microenvironment of glioblastoma and promote its migration and invasion. ß3GNT9 can be used as a potential independent prognostic biomarker for patients with glioblastoma.

Early gut microbiological changes and metabolomic changes in patients with sepsis: a preliminary study.

The gut microbiota is closely related to the development of sepsis. The aim of this study was to explore changes in the gut microbiota and gut metabolism, as well as potential relationships between the gut microbiota and environmental factors in the early stages of sepsis. Fecal samples were collected from 10 septic patients on the first and third days following diagnosis in this study. The results showed that in the early stages of sepsis, the gut microbiota is dominated by microorganisms that are tightly associated with inflammation, such as Escherichia-Shigella, Enterococcus, Enterobacteriaceae, and Streptococcus. On sepsis day 3 compared to day 1, there was a significant decrease in Lactobacillus and Bacteroides and a significant increase in Enterobacteriaceae, Streptococcus, and Parabacteroides. Culturomica_massiliensis, Prevotella_7 spp., Prevotellaceae, and Pediococcus showed significant differences in abundance on sepsis day 1, but not on sepsis day 3. Additionally, 2-keto-isovaleric acid 1 and 4-hydroxy-6-methyl-2-pyrone metabolites significantly increased on sepsis day 3 compared to day 1. Prevotella_7 spp. was positively correlated with phosphate and negatively correlated with 2-keto-isovaleric acid 1 and 3-hydroxypropionic acid 1, while Prevotella_9 spp. was positively correlated with sequential organ failure assessment score, procalcitonin and intensive care unit stay time. In conclusion, the gut microbiota and metabolites are altered during sepsis, with some beneficial microorganisms decreasing and some pathogenic microorganisms increasing. Furthermore, Prevotellaceae members may play different roles in the intestinal tract, with Prevotella_7 spp. potentially possessing beneficial health properties and Prevotella_9 spp. potentially playing a promoting role in sepsis.

Proposal of an automated tumor-stromal ratio assessment algorithm and a nomogram for prognosis in early-stage invasive breast cancer.

BACKGROUND: The tumor-stromal ratio (TSR) has been verified to be a prognostic factor in many solid tumors. In most studies, it was manually assessed on routinely stained H&E slides. This study aimed to assess the TSR using image analysis algorithms developed by the Qupath software, and integrate the TSR into a nomogram for prediction of the survival in invasive breast cancer (BC) patients. METHODS: A modified TSR assessment algorithm based on the recognition of tumor and stroma tissues was developed using the Qupath software. The TSR of 234 invasive BC specimens in H&E-stained tissue microarrays (TMAs) were assessed with the algorithm and categorized as stroma-low or stroma-high. The consistency of TSR estimation between Qupath prediction and pathologist annotation was analyzed. Univariable and multivariable analyses were applied to select potential risk factors and a nomogram for predicting survival in invasive BC patients was constructed and validated. An extra TMA containing 110 specimens was obtained to validate the conclusion as an independent cohort. RESULTS: In the discovery cohort, stroma-low and stroma-high were identified in 43.6% and 56.4% cases, respectively. Good concordance was observed between the pathologist annotated and Qupath predicted TSR. The Kaplan-Meier curve showed that stroma-high patients were associated with worse 5-DFS compared to stroma-low patients (p = 0.007). Multivariable analysis identified age, T stage, N status, histological grade, ER status, HER-2 gene, and TSR as potential risk predictors, which were included in the nomogram. The nomogram was well calibrated and showed a favorable predictive value for the recurrence of BC. Kaplan-Meier curves showed that the nomogram had a better risk stratification capability than the TNM staging system. In the external validation of the nomogram, the results were further validated. CONCLUSIONS: Based on H&E-stained TMAs, this study successfully developed image analysis algorithms for TSR assessment and constructed a nomogram for predicting survival in invasive BC.

Comparison of Efficacy and Safety of TACE Combined with Microwave Ablation and TACE Combined with Cryoablation in the Treatment of Large Hepatocellular Carcinoma.

Purpose: To retrospectively evaluate the efficacy and safety of TACE combined with microwave ablation (MWA) and TACE combined with cryoablation (CRA) in the treatment of large hepatocellular carcinoma. Methods: A retrospective analysis was performed on 81 patients with large hepatocellular carcinoma (tumor diameter 5～8 cm cm) who received TACE combined with ablation in our hospital from February 2015 to February 2019. The study patients were divided into TACE combined with MWA group (T-MWA, n = 41) and TACE combined with CRA group (T-CRA, n = 40) according to the treatment plan. Overall survival (OS) and progress free survival (PFS) were compared between the two groups, and complications were observed. Survival curves for OS and PFS were constructed by the Kaplan-Meier method. Differences in overall survival were compared using the log-rank test. Results: There was no statistical difference in general conditions between the two groups of patients. The results showed that 30 (73.2%) patients in T-MWA group achieved objective response (OR) and 39 (95.1%) patients achieved disease control (DC), compared with 24 (60.0%) patients in T-CRA group who achieved objective response (OR) and 37 (92.5%) patients who achieved disease control (DC). The median OS was 19.2 months in the T-MWA group and 18.6 months in the T-CRA group (P=0.64). The median PFS was 9.3 months in the T-MWA group and 12.3 months in the T-CRA group (P=0.6). Univariate and multivariate analysis showed that portal vein tumor thrombus (PVTT), intrahepatic tumor diameter, and the number of tumor lesions were common prognostic factors for OS and PFS. In terms of surgery-related complications and adverse reactions, abdominal pain and gastrointestinal reactions were observed in 13 (31.7%) and 11(26.8%) cases in the T-MWA group, while we observed 4 (10.0%) and 2 (5.0%) cases in the T-CRA group, respectively. The difference between the two was statistically significant (P < 0.05). Conclusion: TACE combined with MWA and TACE combined with CRA were equally effective in the treatment of large hepatocellular carcinoma. TACE-CRA can effectively reduce the incidence of abdominal pain and gastrointestinal reactions in patients. However, compared with TACE-MWA, TACE-CRA is more likely to cause thrombocytopenia.

Primary malignant pericardial mesothelioma with a survival of 2.5 years: a case report.

Background: Primary malignant pericardial mesothelioma (PMPM) is a highly malignant tumor originating in the pericardium serosum with clinical manifestations presenting as constrictive pericarditis, with pericardial tamponade and heart failure. Malignant pericardial mesothelioma is rare and has a poor prognosis, with an average survival time of 6-10 months. Case Description: Herein, we report the case of a 57-year-old female who developed chest tightness and panic for no obvious reason. She was diagnosed with tuberculous pericarditis via multiple examinations including positron emission tomography/computed tomography (PET/CT), pleural biochemical routine, tuberculin purified protein derivative (PPD) test, T cell spot (T-SPOT) test, and echocardiography, and was experienced intermittent relief after anti-tuberculosis treatment. On 21 July, 2020, pericardiectomy was performed due to poor therapeutic effect, and the postoperative pathological diagnosis was malignant mesothelioma. After discussing treatment plans and considering the prognosis, the patient opted for palliative care. Subsequently, her symptoms gradually worsened, with chest tightness, shortness of breath, palpitations at rest, frequent arrhythmias, heart failure, cardiogenic shock, and multiple plasma chamber effusions. This case showed that the most common misdiagnosis of PMPM is tuberculous pericarditis, which needs to be differentiated from pleural mesothelioma with pericardial metastasis. Conclusions: The diagnosis of PMPM is usually made by pathologic surgery or histopathological examination to determine the specific disease location. In addition, pericardiocentesis fluid exfoliation cytology, imaging and echocardiography can assist diagnosis. Due to the lack of effective treatment for PMPM, timely surgery and postoperative adjuvant chemotherapy are needed to improve the quality of life of patients and prolong their survival time.

Changes in the microbiota in different intestinal segments of mice with sepsis.

Introduction: The small intestine, as the main digestion and absorption site of the gastrointestinal tract, is often overlooked in studies, and the overall microbiota does not reflect the makeup of the microbiota in different segments of the intestine. Therefore, we aimed to exclude the influence of routine ICU treatment measures on sepsis patients and observed changes in the diversity and abundance of gut microbiota in different intestinal segments of septic mice. Methods: The mice were randomly divided into the CLP6h group and the sham group. The contents of the colon and small intestine of the experimental group and the control group were collected after 6 h. Results: After CLP, the number and structure of the gut microbiota in the colon changed most obviously, among which Bacteroidetes had the most significant changes. Akkermansia, D.Firmicutes_bacterium_M10_2, Blautia, Bifidobacterium, Lactobacillus, Candidatus_Arthromitus, and Muribaculaceae were changed in the colon. Lactobacillus, Bifidobacterium, Akkermansia, Blautia, Candidatus_Arthromitus, and Lachnospiraceae_NK4A136_group were changed in the small intestine. Discussion: Our experiment found that there were different numbers of unique and common gut microbiota in the small intestine and colon after sepsis, and the gut microbiota of the colon changed more drastically after sepsis than the small intestine. Thus, we should focus on protective gut microbiota and mucin-degrading microbes. We hope that these results will provide help for sepsis treatment in the future.

Anticoagulation delay does not affect the functional outcome of cerebral venous thrombosis.

Available knowledge about the impact of anticoagulation delay on outcomes of patients with cerebral venous thrombosis (CVT) is limited. We therefore assessed the factors influencing anticoagulation delay and investigated the effect of this delay on outcomes of CVT patients. Anticoagulation delay was defined as the time interval between symptom onset and anticoagulation initiation. The primary outcome was a modified Rankin Scale (mRS) score > 2 at the final follow-up. A total of 164 eligible patients were included. The median anticoagulation delay was 9 days. Cerebral hemorrhage on admission neuroimaging correlated with earlier anticoagulation (p = 0.040). Anticoagulation delay was not associated with poor functional outcome (mRS > 2), but it was associated with residual headache across the entire cohort (earlier anticoagulation: 15/76 [19.7%] vs. later anticoagulation: 28/79 [35.4%]; p = 0.029) and in the subgroup with isolated intracranial hypertension (earlier anticoagulation: 4/25 [16.0%] vs. later anticoagulation: 14/27 [51.9%]; p = 0.007). Anticoagulation delay was found to be common among patients with CVT. Anticoagulation delay was not associated with poor functional outcome, but may have led to an increased risk of residual headache across our entire cohort and in the subgroup with isolated intracranial hypertension.

TOPK Promotes Microglia/Macrophage Polarization towards M2 Phenotype via Inhibition of HDAC1 and HDAC2 Activity after Transient Cerebral Ischemia.

T-LAK-cell-originated protein kinase (TOPK) is a newly identified member of the mitogen-activated protein kinase family. Our previous study has showed that TOPK has neuroprotective effects against cerebral ischemia-reperfusion injury. Here, we investigated the involvement of TOPK in microglia/ macrophage M1/M2 polarization and the underlying epigenetic mechanism. The expression profiles, co-localization and in vivo interaction of TOPK, M1/M2 surface markers, and HDAC1/HDAC2 were detected after middle cerebral artery occlusion models (MCAO). We demonstrated that TOPK, the M2 surface markers CD206 and Arg1, p-HDAC1, and p-HDAC2 showed a similar pattern of in vivo expression over time after MCAO. TOPK co-localized with CD206, p-HDAC1, and p-HDAC2 positive cells, and was shown to bind to HDAC1 and HDAC2. In vitro study showed that TOPK overexpression in BV2 cells up-regulated CD206 and Arg1, and promoted the phosphorylation of HDAC1 and HDAC2. In addition, TOPK overexpression also prevented LPS plus IFN-γ-induced M1 transformation through reducing release of inflammatory factor of M1 phenotype TNF-α, IL-6 and IL-1ß, and increasing TGF-ß release and the mRNA levels of TGF-ß and SOCS3, cytokine of M2 phenotype and its regulator. Moreover, the increased TNF-α induced by TOPK siRNA could be reversed by HDAC1/HDAC2 inhibitor, FK228. TOPK overexpression increased M2 marker expression in vivo concomitant with the amelioration of cerebral injury, neurological functions deficits, whereas TOPK silencing had the opposite effects, which were completely reversed by the FK228 and partially by the SAHA. These findings suggest that TOPK positively regulates microglia/macrophage M2 polarization by inhibiting HDAC1/HDAC2 activity, which may contribute to its neuroprotective effects against cerebral ischemia-reperfusion injury.

Limb Remote Ischemic Conditioning Promotes Myelination by Upregulating PTEN/Akt/mTOR Signaling Activities after Chronic Cerebral Hypoperfusion.

Limb Remote ischemic conditioning (LRIC) has been proved to be a promising neuroprotective method in white matter lesions after ischemia; however, its mechanism underlying protection after chronic cerebral hypoperfusion remains largely unknown. Here, we investigated whether LRIC promoted myelin growth by activating PI3K/Akt/mTOR signal pathway in a rat chronic hypoperfusion model. Thirty adult male Sprague Dawley underwent permanent double carotid artery (2VO), and limb remote ischemic conditioning was applied for 3 days after the 2VO surgery. Cognitive function, oligodendrocyte counts, myelin density, apoptosis and proliferation activity, as well as PTEN/Akt/mTOR signaling activity were determined 4 weeks after treatment. We found that LRIC significantly inhibited oligodendrocytes apoptosis (p<0.05), promoted myelination (p<0.01) in the corpus callosum and improved spatial learning impairment (p<0.05) at 4 weeks after chronic cerebral hypoperfusion. Oligodendrocytes proliferation, along with demyelination, in corpus callosum were not obviously affected by LRIC (p>0.05). Western blot analysis indicated that LRIC upregulated PTEN/Akt/mTOR signaling activities in corpus callosum (p<0.05). Our results suggest that LRIC exerts neuroprotective effect on white matter injuries through activating PTEN/Akt/mTOR signaling pathway after chronic cerebral hypoperfusion.

Cerebral watershed infarcts may be induced by hemodynamic changes in blood flow.

OBJECTIVES: A watershed infarct is defined as an ischemic lesion at the border zones between territories of two major arteries. The pathogenesis of watershed infarcts, specifically whether they are caused by hemodynamic or embolic mechanisms, has long been debated. In this study, we aimed to examine whether watershed infarcts can be induced by altering the hemodynamic conditions in rats. MATERIALS AND METHODS: In phase one, to determine the proper clamping duration for a reproducible infarct, 30 rats were equally divided into 5 subgroups and underwent bilateral common carotid artery (CCA) clamping for different durations (0.5, 1.0, 1.5, 2.0, and 3.0 hours). In phase two, to analyze the types of infarcts induced by bilateral CCA clamping, 40 rats were subjected to bilateral CCA clamping for 2 hours. As a control, 8 rats underwent all the operation procedures except bilateral CCA clamping. We performed 7.0T magnetic resonance imaging on the surviving rats on the second day to evaluate the extent of the infarcts. We further identified and examined the infarcts with brain slices stained using 2, 3, 5-triphenyltetrazolium chloride (TTC) on the third day. RESULTS: After 2 hours of bilateral CCA clamping, cerebral infarction occurred in 42% of surviving rats (13/31). The majority of the ischemic lesions were located in watershed regions of the brain, demonstrated by both MRI and TTC staining. CONCLUSION: Watershed infarcts were induced through changing hemodynamic conditions by bilateral CCA clamping in rats. This method may lead to the development of a reliable rodent model for watershed infarcts.

Local cerebral hypothermia induced by selective infusion of cold lactated ringer's: a feasibility study in rhesus monkeys.

BACKGROUND AND OBJECTIVE: Hypothermia has shown promise as a neuroprotective strategy for stroke. The use of whole body hypothermia has limited clinical utility due to many severe side effects. Selective brain cooling, or local brain hypothermia, has been previously proposed as an alternative treatment strategy. This study investigated the safety, feasibility, and efficacy of selective brain hypothermia induced by local infusion of ice-cold lactated Ringer's solution in rhesus monkeys. METHODS: Eight male rhesus monkeys were used in this study. Brain temperature in the territory supplied by middle cerebral artery (MCA) was reduced by infusing 100 mL of ice-cold (0 °C) lactated Ringer's solution over 20 min via a micro-catheter placed in the proximal MCA (n = 4). Vital signs and the temperature of the brain and rectum were monitored before and after infusion. Transcranial Doppler, Magnetic resonance imaging (MRI), and digital subtraction angiography (DSA) were used to evaluate cerebral blood flow, cerebrovascular reactivity (CVR), cerebral edema, and vasospasm. Another cohort of rhesus monkeys (n = 4) were used as systemic cooling controls. RESULTS: Oxygen saturation, blood pressure, heart rate, and hematologic analysis of the two groups remained within the normal range after infusion. Mild cerebral hypothermia (<35 °C) was achieved in 10 min (0.3 °C/min) and was maintained for 20 min in local cortex and striatum following local infusion. The average lowest cerebral temperature in the locally cooled animals was 33.9 ± 0.3 °C in the striatum following 20-min infusion. This was not observed in animals cooled by systemic infusion. The decreases in the rectal temperature for local and systemic infusion were 0.5 ± 0.2 °C and 0.5 ± 0.3 °C, respectively. Selective brain cooling did not cause any cerebral edema as determined by MRI or vasospasm in the perfused vessel based on DSA. Selective cerebral hypothermia did not significantly alter CVR. CONCLUSION: Local infusion of ice-cold lactated Ringer's solution via micro-catheter is a safe and effective method for selective cerebral hypothermia. This cooling method could potentially be developed as a new treatment in acute ischemic stroke.