Cognitive Screening via Comprehensive Geriatric Assessment of Older Patients for the Risk Factors of Hospital Revisit/Readmission after Emergency Department Visit at 3-Month Follow-Up.

INTRODUCTION: Cognitive impairment (COIM) is a major challenge for healthcare systems and is associated with an increased risk of adverse outcomes in older people visiting emergency departments (EDs). Owing to global aging, both cognitive screening and comprehensive geriatric assessment (CGA) application in ED settings are developing areas of geriatric emergency medicine. Meanwhile, the association between clinical outcomes of COIM; cognitive impairment, no dementia (CIND); and dementia in the ED could be better investigated. Our study aims to identify individuals with COIM from older patients in the ED via CGA and to describe the association of CIND and dementia with prognosis in ED visits. METHODS: A prospective cross-sectional study was conducted in the ED of the Taipei Veterans General Hospital, a medical center located in Taipei, Taiwan, from August 2018 to November 2020. Patients aged ≥75 years with and without COIM were compared using data obtained from the CGAs conducted by trained nurses. RESULTS: A total of 823 older patients were enrolled in the study and underwent CGA. Of these, 463 (56.3%) were diagnosed with COIM, of which 292 (35.5%) were diagnosed with dementia; and 171 (20.8%), CIND. Between the no-COIM and COIM groups, the COIM group had a higher rate of hospital admission (p = 0.002) and mortality at 3 months (p < 0.05). Among the no-COIM, CIND, and dementia groups, ED disposition (p = 0.001) and the rate of revisit/readmission (p < 0.05) showed significant differences. In particular, the dementia group had a significantly higher rate of revisit/readmission as compared to the CIND group among the three groups. DISCUSSION/CONCLUSION: Older patients with COIM had a higher rate of hospital admission and mortality at the 3-month follow-up than older patients without COIM. Among the no-COIM, CIND, and dementia groups, patients with dementia had significantly increased risks of hospital admission and revisit/readmission. The early detection of COIM, and even dementia, could help ED physicians formulate strategies with geriatric specialists to improve mortality outcomes and revisit/readmission.

S-glutathionylation uncouples eNOS and regulates its cellular and vascular function.

Endothelial nitric oxide synthase (eNOS) is critical in the regulation of vascular function, and can generate both nitric oxide (NO) and superoxide (O(2)(•-)), which are key mediators of cellular signalling. In the presence of Ca(2+)/calmodulin, eNOS produces NO, endothelial-derived relaxing factor, from l-arginine (l-Arg) by means of electron transfer from NADPH through a flavin containing reductase domain to oxygen bound at the haem of an oxygenase domain, which also contains binding sites for tetrahydrobiopterin (BH(4)) and l-Arg. In the absence of BH(4), NO synthesis is abrogated and instead O(2)(•-) is generated. While NOS dysfunction occurs in diseases with redox stress, BH(4) repletion only partly restores NOS activity and NOS-dependent vasodilation. This suggests that there is an as yet unidentified redox-regulated mechanism controlling NOS function. Protein thiols can undergo S-glutathionylation, a reversible protein modification involved in cellular signalling and adaptation. Under oxidative stress, S-glutathionylation occurs through thiol-disulphide exchange with oxidized glutathione or reaction of oxidant-induced protein thiyl radicals with reduced glutathione. Cysteine residues are critical for the maintenance of eNOS function; we therefore speculated that oxidative stress could alter eNOS activity through S-glutathionylation. Here we show that S-glutathionylation of eNOS reversibly decreases NOS activity with an increase in O(2)(•-) generation primarily from the reductase, in which two highly conserved cysteine residues are identified as sites of S-glutathionylation and found to be critical for redox-regulation of eNOS function. We show that eNOS S-glutathionylation in endothelial cells, with loss of NO and gain of O(2)(•-) generation, is associated with impaired endothelium-dependent vasodilation. In hypertensive vessels, eNOS S-glutathionylation is increased with impaired endothelium-dependent vasodilation that is restored by thiol-specific reducing agents, which reverse this S-glutathionylation. Thus, S-glutathionylation of eNOS is a pivotal switch providing redox regulation of cellular signalling, endothelial function and vascular tone.

IKK inhibition prevents PM2.5-exacerbated cardiac injury in mice with type 2 diabetes.

Epidemiological studies have found that individuals with diabetes mellitus (DM) display an increased susceptibility for adverse cardiovascular outcomes when exposed to air pollution. This study was conducted to explore the potential mechanism linking ambient fine particles (PM2.5) and heart injury in a Type 2 DM (T2DM) animal model. The KKay mouse, an animal model of T2DM, was exposed to concentrated ambient PM2.5 or filtered air for 8 weeks via a versatile aerosol exposure and concentrator system. Simultaneously, an inhibitor of IκB kinase-2 (IKK-â) (IMD-0354), which is a blocker of nuclear factor κB (NF-κB) nuclear translocation, was administrated by intracerebroventricular injection (ICV) to regulate the NF-êB pathway. The results showed that ambient PM2.5 induced the increase of, NF-êB, cyclooxygenase-2 (COX-2) and mitogen activated protein kinase (MAPK) expression in cardiac tissue, and that IMD-0354 could alleviate the inflammatory injury. The results suggested that the NF-êB pathway plays an important role in mediating the PM2.5-induced cardiovascular injury in the T2DM model. Inhibiting NFκB may be a therapeutic option in air-pollution-exacerbated cardiovascular injury in diabetes mellitus.

Exaggerated effects of particulate matter air pollution in genetic type II diabetes mellitus.

BACKGROUND: Prior experimental and epidemiologic data support a link between exposure to fine ambient particulate matter (<2.5 µm in aerodynamic diameter, PM2.5) and development of insulin resistance/Type II diabetes mellitus. This study was designed to investigate whether inhalational exposure of concentrated PM2.5 in a genetically susceptible animal model would result in abnormalities in energy metabolism and exacerbation of peripheral glycemic control. METHODS: KKay mice, which are susceptible to Type II DM, were assigned to either concentrated ambient PM2.5 or filtered air (FA) for 5-8 weeks via a whole body exposure system. Glucose tolerance, insulin sensitivity, oxygen consumption and heat production were evaluated. At euthanasia, blood, spleen and visceral adipose tissue were collected to measure inflammatory cells using flow cytometry. Standard immnunohistochemical methods, western blotting and quantitative PCR were used to assess targets of interest. RESULTS: PM2.5 exposure influenced energy metabolism including O2 consumption, CO2 production, respiratory exchange ratio and thermogenesis. These changes were accompanied by worsened insulin resistance, visceral adiposity and inflammation in spleen and visceral adipose depots. Plasma adiponectin were decreased in response to PM2.5 exposure while leptin levels increased. PM2.5 exposure resulted in a significant increase in expression of inflammatory genes and decreased UCP1 expression in brown adipose tissue and activated p38 and ERK pathways in the liver of the KKay mice. CONCLUSIONS: Concentrated ambient PM2.5 exposure impairs energy metabolism, concomitant with abnormalities in glucose homeostasis, increased inflammation in insulin responsive organs, brown adipose inflammation and results in imbalance in circulating leptin/adiponectin levels in a genetically susceptible diabetic model. These results provide additional insights into the mechanisms surrounding air pollution mediated susceptibility to Type II DM.

Central IKKß inhibition prevents air pollution mediated peripheral inflammation and exaggeration of type II diabetes.

BACKGROUND: Prior experimental and epidemiologic data support a link between exposure to fine ambient particulate matter (<2.5 µm in aerodynamic diameter, PM2.5) and development of insulin resistance/Type II diabetes mellitus (Type II DM). We investigated the role of hypothalamic inflammation in PM2.5-mediated diabetes development. METHODS: KKay mice, a genetically susceptible model of Type II DM, were assigned to either concentrated PM2.5 or filtered air (FA) for 4-8 weeks via a versatile aerosol concentrator and exposure system, or administered intra-cerebroventricular with either IKKß inhibitor (IMD-0354) or TNFα antibody (infliximab) for 4-5 weeks simultaneously with PM2.5 exposure. Glucose tolerance, insulin sensitivity, oxygen consumption and heat production were evaluated. At euthanasia, blood, spleen, visceral adipose tissue and hypothalamus were collected to measure inflammatory cells using flow cytometry. Standard immunohistochemical methods and quantitative PCR were used to assess targets of interest. RESULTS: PM2.5 exposure led to hyperglycemia and insulin resistance, which was accompanied by increased hypothalamic IL-6, TNFα, and IKKß mRNA expression and microglial/astrocyte reactivity. Targeting the NFκB pathway with intra-cerebroventricular administration of an IKKß inhibitor [IMD-0354, n = 8 for each group)], but not TNFα blockade with infliximab [(n = 6 for each group], improved glucose tolerance, insulin sensitivity, rectified energy homeostasis (O2 consumption, CO2 production, respiratory exchange ratio and heat generation) and reduced peripheral inflammation in response to PM2.5. CONCLUSIONS: Central inhibition of IKKß prevents PM2.5 mediated peripheral inflammation and exaggeration of type II diabetes. These results provide novel insights into how air pollution may mediate susceptibility to insulin resistance and Type II DM.

Superoxide induces endothelial nitric-oxide synthase protein thiyl radical formation, a novel mechanism regulating eNOS function and coupling.

An increase in production of reactive oxygen species resulting in a decrease in nitric oxide bioavailability in the endothelium contributes to many cardiovascular diseases, and these reactive oxygen species can oxidize cellular macromolecules. Protein thiols are critical reducing equivalents that maintain cellular redox state and are primary targets for oxidative modification. We demonstrate endothelial NOS (eNOS) oxidant-induced protein thiyl radical formation from tetrahydrobiopterin-free enzyme or following exposure to exogenous superoxide using immunoblotting, immunostaining, and mass spectrometry. Spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) followed by immunoblotting using an anti-DMPO antibody demonstrated the formation of eNOS protein radicals, which were abolished by superoxide dismutase and L-NAME, indicating that protein radical formation was due to superoxide generation from the eNOS heme. With tetrahydrobiopterin-reconstituted eNOS, eNOS protein radical formation was completely inhibited. Using mass spectrometric and mutagenesis analysis, we identified Cys-908 as the residue involved in protein radical formation. Mutagenesis of this key cysteine to alanine abolished eNOS thiyl radical formation and uncoupled eNOS, leading to increased superoxide generation. Protein thiyl radical formation leads to oxidation or modification of cysteine with either disulfide bond formation or S-glutathionylation, which induces eNOS uncoupling. Furthermore, in endothelial cells treated with menadione to trigger cellular superoxide generation, eNOS protein radical formation, as visualized with confocal microscopy, was increased, and these results were confirmed by immunoprecipitation with anti-eNOS antibody, followed by immunoblotting with an anti-DMPO antibody. Thus, eNOS protein radical formation provides the basis for a mechanism of superoxide-directed regulation of eNOS, involving thiol oxidation, defining a unique pathway for the redox regulation of cardiovascular function.

Effect of co-exposure to nickel and particulate matter on insulin resistance and mitochondrial dysfunction in a mouse model.

BACKGROUND: It has been well recognized that toxicity of fine ambient air particulate matter (PM(2.5)) may depend on its chemical constituents, including components such as soluble metals that may theoretically exert distinctive effects. We have recently demonstrated an important effect of PM(2.5) on metabolic function. Since transition metals, such as nickel (Ni), represent an important component of exposure in certain environments, and may significantly influence the toxicity of inhalational exposure, we investigated the effects of Ni as a variable component of ambient PM(2.5) exposure. METHODS: Male ApoE knockout mice were exposed to filtered air (FA), fine-sized nickel sulfate particles alone (Ni) at 0.44 µg/m(3), concentrated ambient air PM(2.5) (CAPs) at a mean of 70 µg/m(3), or CAPs+Ni in Tuxedo, NY, 6 hours/day, 5 days/week, for 3 months. RESULTS: Exposure to Ni, irrespective of co-exposure to CAPs, resulted in body weight gain, while exposure to CAPs+Ni significantly enhanced fasting glucose and worsened insulin resistance measures (HOMA-IR), when compared with exposure to CAPs alone. CAPs+Ni exposure induced a significant decrease in phosphorylation of AMP-activated protein kinase (AMPK) α. Exposure to Ni or CAPs+Ni significantly induced microcirculatory dysfunction and increased monocytic cell infiltration into lung and adipose, and decreased uncoupling protein 1 expression at gene and protein levels and several brown adipocyte-specific genes in adipose tissue. CONCLUSIONS: Ni exposure has effects on metabolic and inflammatory parameters that are comparable to that of CAPs. Additionally, Ni synergistically exacerbates CAPs-induced adverse effects on some of, but not all of, these parameters, that may be mediated via the AMPK signaling pathway. These findings have important implications for inhaled transition metal toxicity that may exert synergistic effects with other PM(2.5) components.

A 44-Year-Old Man With Acute Mutism: Acute Stroke, Psychiatric Disorder, or Substance Abuse?

Mutism is a common presentation of psychiatric diseases. However, patients presenting to the emergency department with mutism should be assumed to have an organic pathology irrespective of their psychiatric history. Little is known about the causality between mutism and illicit drug use. We report a case of a 44-year-old man with acute mutism who was initially diagnosed with ischemic cerebral infarction involving the dorsolateral frontal cortex causing Broca's aphasia. He was later found to have a history of amphetamine, ketamine, and new psychoactive substance use. Substance abuse could be a precipitating factor for acute stroke, especially among patients aged below 55 years. Patients should be routinely screened and counseled regarding illicit drug use. The present case report highlights the possibility that transient ischemia could be associated with acute mutism in drug abusers. Prompt acquisition of drug abuse history or basic drug screening is especially mandatory.

Comparison of outcomes in emergency department revisiting patients before and after coronavirus disease 2019 epidemic.

BACKGROUND AND IMPORTANCE: The outbreak of COVID-19 challenged the global health system and specifically impacted the emergency departments (EDs). Studying the quality indicators of ED care under COVID-19 has been a necessary task, and ED revisits have been used as an indicator to monitor ED performance. OBJECTIVES: The study investigated whether discrepancies existed among ED revisiting cases before and after COVID-19 and whether the COVID-19 epidemic was a predictor of poor outcomes of ED revisits. DESIGN: Retrospective study. SETTINGS AND PARTICIPANTS: We used electronic health records data from a tertiary medical center. Data of patients with 72-h ED revisit after the COVID-19 epidemic were collected from February 2020 to June 2020 and compared with those of patients before COVID-19, from February 2019 to June 2019. OUTCOME MEASURES AND ANALYSIS: The investigated outcomes included hospital admission, ICU admission, out-of-hospital cardiac arrest, and subsequent inhospital mortality. Univariate and multivariate logistic regression models were used to identify independent predictors of 72-h ED revisit outcomes. MAIN RESULTS: In total, 1786 patients were enrolled in our study - 765 in the COVID group and 1021 in the non-COVID group. Compared with the non-COVID group, patients in the COVID group were younger (53.9 vs. 56.1 years old; P = 0.002) and more often female (66.1% vs. 47.3%; P < 0.001) and had less escalation of triage level (11.6% vs. 15.0%; P = 0.041). The hospital admission and inhospital mortality rates in the COVID and non-COVID groups were 33.9% vs. 32.0% and 2.7% vs. 1.5%, respectively. In the logistic regression model, the COVID-19 period was significantly associated with inhospital mortality (adjusted odds ratio, 2.289; 95% confidence interval, 1.059-4.948; P = 0.035). CONCLUSION: Patients with 72-h ED revisits showed distinct demographic and clinical patterns before and after the COVID-19 epidemic; the COVID-19 period was an independent predictor of increased inhospital mortality.

Geriatric syndromes predict mortality of people aged 75+ years in the observation room of emergency department: Towards function-centric emergency medicine.

BACKGROUND: Aging is a complex process involving functional decline, reduced physiological reserve, increased multimorbidity, and impaired homeostasis, all of which collectively generate various health risks for older adults. To predict short-term mortality of non-critical older patients in the observation room of the emergency department (ED) based on function-centric approach instead of disease-centric one. METHODS: We conducted a prospective study enrolling 831 patients aged 75 years and older between 2018 and 2020. Comprehensive geriatric assessment was performed on all patients, and the results were integrated into the care planning process. RESULTS: In total 831 patients (mean age: 84.8 ± 5.8 years) were enrolled and the post-discharge mortality rate was 3.3% (28 deaths) after 3 months, and 5.4% (45 deaths) after 6 months. The independent predictors of 3-month mortality were malnutrition (adjusted odds ratio [OR], 4.77; p < 0.05), incontinence (adjusted OR, 2.58; p < 0.05) and multimorbidity (adjusted OR, 1.51; p < 0.001). For 6-month mortality, malnutrition (adjusted OR, 4.20; p < 0.01), multimorbidity (adjusted OR, 1.40; p < 0.001) and activities of daily living (adjusted OR, 0.99; p < 0.05) were all independent predictors. CONCLUSION: Although ED aims to treat acute and life-threatening conditions, older persons with geriatric syndromes are also at a substantially high risk of adverse outcomes, even mortality. Transitioning of the ED from disease-centric to function-centric services is important for responding to the changing health care needs of super-aged societies.

Gastric Mobility and Gastrointestinal Hormones in Older Patients with Sarcopenia.

Sarcopenia has serious clinical consequences and poses a major threat to older people. Gastrointestinal environmental factors are believed to be the main cause. The aim of this study was to describe the relationship between sarcopenia and gastric mobility and to investigate the relationship between sarcopenia and the concentration of gastrointestinal hormones in older patients. Patients aged ≥ 75 years were recruited for this prospective study from August 2018 to February 2019 at the emergency department. The enrolled patients were tested for sarcopenia. Gastric emptying scintigraphy was conducted, and laboratory tests for cholecystokinin(CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY), nesfatin, and ghrelin were performed during the fasting period. We enrolled 52 patients with mean age of 86.9 years, including 17 (32.7%) patients in the non-sarcopenia group, 17 (32.7%) patients in the pre-sarcopenia group, and 18 (34.6%) in the sarcopenia group. The mean gastric emptying half-time had no significant difference among three groups. The sarcopenia group had significantly higher fasting plasma concentrations of CCK, GLP-1, and PYY. We concluded that the older people with sarcopenia had significantly higher plasma concentrations of CCK, GLP-1, and PYY. In the elderly population, anorexigenic gastrointestinal hormones might have more important relationships with sarcopenia than orexigenic gastrointestinal hormones.

Enhancing the learning and transfer of preprocedural communication skills during clerkship using audio-visual material: a prospective case-controlled study over 2 years.

OBJECTIVE/DESIGN/SETTING: This study aims to develop preprocedural communication-specific framework that emphasises the use of audiovisual materials and compares its acceptability by trainees with a regular module. TRAINEES: Between October 2018 and July 2021, 96 medical clerks were enrolled and randomly divided into regular and intervention groups. Another 48 trainees whose did not join the framework-based training but complete self-assessments were enrolled as the control group. INTERVENTIONS: In the intervention training module, the key steps of preprocedural communication-specific skills were structuralised into a framework using the acronym of OSCAR. PRIMARY AND SECONDARY OUTCOME MEASURES: This study compared the acceptability of trainees for two modules by measuring the degree of increase in the end-of-rotation and follow up (4 weeks later) competency from baseline by trainees' self-assessments and physician assessments after serial trainings. RESULTS: In comparison with regular group trainees, greater degree of improvements (framework-1 statement: 111%±13% vs 27%±5%, p<0.001; framework-2 statement: 77%±9% vs 48%±2%, p<0.05; skill-1 statement: 105%±9% vs 48%±3%, p<0.001); skill-2 statement: 71%±11% vs 50%±9%, p<0.05) were noted in the framework-related and skill-related statement 1-2 (the familiarity and confidence to use the framework and skills) than those of intervention group. At the end-of-rotation stage, the trainees ability to use the 'A-step: using audiovisual materials' of the OSCAR was significantly improved (229%±13%, p<0.001), compared with other steps. In the intervention group, the degree of improvement of the end-of-rotation data of trainees' self-assessment from baseline was significantly correlated with the degree of the improvement in physicians' assessment data in the aspects of skills, framework and steps in framework (R=0.872, p<0.01; R=0.813, p<0.001; R=0.914, p<0.001). CONCLUSIONS: The OSCAR framework-based intervention module is well accepted by medical clerks and motivates them to integrate the acquired skills in clinical practice, which leads to trainees' primary care patients being satisfied with their preprocedural communication.

Effects of Sodium Silicate Complex against Hemorrhagic Activities Induced by Protobothrops mucrosquamatus Venom.

Protobothrops mucrosquamatus poses a serious medical threat to humans in Southern and Southeastern Asia. Hemorrhage is one of the conspicuous toxicities related to the pathology of P. mucrosquamatus envenoming. Previous in vitro and in vivo studies showed that a silica-derived reagent, sodium silicate complex (SSC), was able to neutralize hemorrhagic and proteolytic activities induced by pit viper venoms, including Crotalus atrox, Agkistrodoncontortrix contortrix and Agkistrodon piscivorus leucostoma. In this study, we validated that SSC could neutralize enzymatic and toxic effects caused by the venom of P. mucrosquamatus. We found that SSC inhibited the hemolytic and proteolytic activities induced by P. mucrosquamatus venom in vitro. In addition, we demonstrated that SSC could block intradermal hemorrhage caused by P. mucrosquamatus venom in a mouse model. Finally, SSC could neutralize lethal effects of P. mucrosquamatus venom in the mice. Therefore, SSC is a candidate for further development as a potential onsite first-aid treatment for P. mucrosquamatus envenoming.

Risk of anemia in morbidly obese patients after bariatric surgery in Taiwan.

BACKGROUND: Bariatric surgery is one of most effective long-term treatments for morbid obesity. However, post-bariatric surgery anemia is identified as a common adverse effect and remains a challenge nowadays. AIM: To estimate the risk of post-bariatric surgery anemia and to stratify the association between age, gender, and types of surgery. METHODS: This study is a population-based cohort study. We conducted this nationwide study using claims data from National Health Insurance Research Database in Taiwan. There were 4373 morbidly obese patients in this study cohort. RESULTS: Among patients who were diagnosed with morbid obesity, 2864 received bariatric surgery. All obesity-associated comorbidities decreased in the surgical group. Increasing risk of post-bariatric surgery anemia among obese patients was found by Cox proportional hazards regression [adjusted hazard ratio (HR): 2.36]. Also, we found significantly increasing cumulative incidence rate of anemia among patients receiving bariatric surgery by log-rank test. After adjusting for age and gender, the increasing incidence of post-bariatric surgery anemia was found among women (adjusted HR: 2.48), patients in the 20-29-year-old group (adjusted HR: 3.83), and patients in the 30-64-year-old group (adjusted HR: 2.37). Moreover, malabsorptive and restrictive procedures had significantly higher adjusted HRs, 3.18 and 1.55, respectively. CONCLUSION: Bariatric surgery give rise to anemia risk among obese patients, specifically in women, young- and middle-aged patients, and patients undergoing malabsorptive procedures in our population-based cohort study in Taiwan.

A Paper-Based Analytical Device for Analysis of Paraquat in Urine and Its Validation with Optical-Based Approaches.

Paraquat is a highly toxic herbicide. Paraquat poisoning is often fatal and is an important public health threat in many places. The quick identification and timely initiation of treatment based on timely analysis of the paraquat concentration in urine/serum could improve the prognosis for patients. However, current paraquat concentration measurements are time-consuming and difficult to implement due to the expensive and bulky equipment required. To address these practical challenges, paper-based devices have emerged as alternative diagnostic tools for improving point-of-care testing. In this study, we demonstrate the successful use of a paper-based analytical device for the accurate detection of urine paraquat concentration. The developed paper-based analytical device employs colorimetric paraquat concentration measurements. The R2 value for the urine paraquat standard curve was 0.9989, with a dynamic range of 0-100 ppm. The limit of detection was 3.01 ppm. Two other optical-based approaches, Spectrochip and NanoDrop, were used for comparison. The results suggest that the developed paper-based analytical device is comparable to other colorimetric measurements, as determined by Bland-Altman analysis. The device was clinically validated using urine from six paraquat-poisoned patients. The results prove that the developed paper-based analytical device is accurate, easy-to-use, and efficient for urine paraquat concentration measurement, and may enable physicians to improve clinical management.

Intermittent cold exposure improves glucose homeostasis associated with brown and white adipose tissues in mice.

AIMS: The discovery of different shades of fat has been implicated in the pathogenesis of obesity-related metabolic disorders. However, the effects of early and intermittent exposure to cold temperature on systemic metabolic changes in adult life remain unclear. MAIN METHODS: To elucidate the impact of cold temperature exposure on metabolic function of adipose tissues, we investigated the glucose homeostasis, activation of brown adipose tissue (BAT) and "browning" of white adipose tissue (WAT) in mice in response to intermittent cold exposure. Mice were exposed to 4 °C, 2h per day and 5 days per week, for 14 weeks. Glucose homeostasis was tested via intraperitoneal glucose tolerance test and insulin tolerance test; body fat mass was evaluated using in vivo magnetic resonance imaging; BAT activity was detected primarily by positron emission tomography/computed tomography; and WAT "browning" was evaluated using immunohistochemistry. KEY FINDINGS: Our results showed that a 14-week cold exposure improved glucose tolerance and enhanced insulin sensitivity, reduced the relative weights of epididymal and retroperitoneal WAT, increased expressions of UCP1 and PGC1α in subcutaneous adipose tissue. SIGNIFICANCE: Intermittent exposure to cold temperature in early life may improve systemic glucose homeostasis and induce WAT "browning", suggesting that an ambient cold temperature exposure may serve as a promising intervention to metabolic disorders.

Air pollution-mediated susceptibility to inflammation and insulin resistance: influence of CCR2 pathways in mice.

BACKGROUND: Epidemiologic and experimental studies support an association between PM2.5 exposure and insulin resistance (IR). Innate immune cell activation has been suggested to play a role in the pathogenesis of these effects. OBJECTIVES: We sought to evaluate the role of CC-chemokine receptor 2 (CCR2) in PM2.5-mediated inflammation and IR. METHODS: Wild-type C57BL/6 and CCR2-/- male mice were fed a high-fat diet and exposed to either concentrated ambient PM2.5 or filtered air for 17 weeks via a whole-body exposure system. We evaluated glucose tolerance and insulin sensitivity. At euthanasia, blood, spleen, and visceral adipose tissue (VAT) were collected, and inflammatory cells were measured using flow cytometry. We used standard immunoblots, immunohistochemical methods, and quantitative PCR (polymerase chain reaction) to assess pathways of interest involving insulin signaling, inflammation, and lipid and glucose metabolism in various organs. Vascular function was assessed using myography. RESULTS: PM2.5 exposure resulted in whole-body IR and increased hepatic lipid accumulation in the liver, which was attenuated in CCR2-/- mice by inhibiting SREBP1c-mediated transcriptional programming, decreasing fatty acid uptake, and suppressing p38 MAPK activity. Abnormal phosphorylation levels of AKT, AMPK in VAT, and adipose tissue macrophage content in wild-type mice were not present in CCR2-/- mice. However, the impaired whole-body glucose tolerance and reduced GLUT-4 in skeletal muscle in response to PM2.5 was not corrected by CCR2 deficiency. CONCLUSIONS: PM2.5 mediates IR by regulating VAT inflammation, hepatic lipid metabolism, and glucose utilization in skeletal muscle via both CCR2-dependent and -independent pathways. These findings provide new mechanistic links between air pollution and metabolic abnormalities underlying IR.

Reversal of SIN-1-induced eNOS dysfunction by the spin trap, DMPO, in bovine aortic endothelial cells via eNOS phosphorylation.

BACKGROUND AND PURPOSE: Nitric oxide (NO) derived from eNOS is mostly responsible for the maintenance of vascular homeostasis and its decreased bioavailability is characteristic of reactive oxygen species (ROS)-induced endothelial dysfunction (ED). Because 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), a commonly used spin trap, can control intracellular nitroso-redox balance by scavenging ROS and donating NO, it was employed as a cardioprotective agent against ED but the mechanism of its protection is still not clear. This study elucidated the mechanism of protection by DMPO against SIN-1-induced oxidative injury to bovine aortic endothelial cells (BAEC). EXPERIMENTAL APPROACH: BAEC were treated with SIN-1, as a source of peroxynitrite anion (ONOO⁻), and then incubated with DMPO. Cytotoxicity following SIN-1 alone and cytoprotection by adding DMPO was assessed by MTT assay. Levels of ROS and NO generation from HEK293 cells transfected with wild-type and mutant eNOS cDNAs, tetrahydrobiopterin bioavailability, eNOS activity, eNOS and Akt kinase phosphorylation were measured. KEY RESULTS: Post-treatment of cells with DMPO attenuated SIN-1-mediated cytotoxicity and ROS generation, restoration of NO levels via increased in eNOS activity and phospho-eNOS levels. Treatment with DMPO alone significantly increased NO levels and induced phosphorylation of eNOS Ser¹¹79 via Akt kinase. Transfection studies with wild-type and mutant human eNOS confirmed the dual role of eNOS as a producer of superoxide anion (O2⁻) with SIN-1 treatment, and a producer of NO in the presence of DMPO. CONCLUSION AND IMPLICATIONS: Post-treatment with DMPO of oxidatively challenged cells reversed eNOS dysfunction and could have pharmacological implications in the treatment of cardiovascular diseases.

Inflammatory response to fine particulate air pollution exposure: neutrophil versus monocyte.

OBJECTIVES: Studies have shown that chronic exposure to ambient fine particulate matter (less than 2.5 µm in aerodynamic diameter, PM2.5) pollution induces insulin resistance through alterations in inflammatory pathways. It is critical to study how the immune system responds to this stimulant, which has been linked to cardiovascular and autoimmune diseases, but few studies have been focused on such involvement of both neutrophils and monocytes in a timely manner. We hypothesized that the neutrophil was involved in the inflammatory response to air pollution. METHODS AND RESULTS: C57BL/6 mice were exposed to PM2.5 or filtered air (6 hours/day, 5 days/week) for 5, 14, and 21 days, respectively, in Columbus, OH. At the end of each of the exposure periods, we investigated the inflammatory response through flow cytometry, histology, intravital microscopy, and real-time PCR. PM2.5-exposed mice demonstrated a significant inflammatory response after 5 days of exposure. In the lung tissue and bronchoalveolar lavage fluid, monocytes/macrophages showed a transient response, while neutrophils showed a cumulative response. In addition, exposure to PM2.5 resulted in elevation of the monocyte chemoattractant protein 1 (MCP-1) cytokine, a monocyte/macrophage attractant in blood, at an early stage of exposure. CONCLUSIONS: These findings suggest that PM2.5 exposure induces the inflammatory responses from both macrophages and neutrophils involvement.

Exercise protects against diet-induced insulin resistance through downregulation of protein kinase Cß in mice.

Physical exercise is an important and effective therapy for diabetes. However, its underlying mechanism is not fully understood. Protein kinase Cß (PKCß) has been suggested to be involved in the pathogenesis of obesity and insulin resistance, but the role of PKCß in exercise-induced improvements in insulin resistance is completely unknown. In this study, we evaluated the involvement of PKCß in exercise-attenuated insulin resistance in high-fat diet (HFD)-fed mice. PKCß(-/-) and wild-type mice were fed a HFD with or without exercise training. PKC protein expression, body and tissue weight change, glucose and insulin tolerance, metabolic rate, mitochondria size and number, adipose inflammation, and AKT activation were determined to evaluate insulin sensitivity and metabolic changes after intervention. PKCß expression decreased in both skeletal muscle and liver tissue after exercise. Exercise and PKCß deficiency can alleviate HFD-induced insulin resistance, as evidenced by improved insulin tolerance. In addition, fat accumulation and mitochondrial dysfunction induced by HFD were also ameliorated by both exercise and PKCß deficiency. On the other hand, exercise had little effect on PKCß(-/-) mice. Further, our data indicated improved activation of AKT, the downstream signal molecule of insulin, in skeletal muscle and liver of exercised mice, whereas PKCß deficiency blunted the difference between sedentary and exercised mice. These results suggest that downregulation of PKCß contributes to exercise-induced improvement of insulin resistance in HFD-fed mice.