Neurovirulent cytokines increase neuronal excitability in a model of coronavirus-induced neuroinflammation.

BACKGROUND: Neurological manifestations of severe coronavirus infections, including SARS-CoV-2, are wide-ranging and may persist following virus clearance. Detailed understanding of the underlying changes in brain function may facilitate the identification of therapeutic targets. We directly tested how neocortical function is impacted by the specific panel of cytokines that occur in coronavirus brain infection. Using the whole-cell patch-clamp technique, we determined how the five cytokines (TNFα, IL-1ß, IL-6, IL-12p40 and IL-15 for 22-28-h) at concentrations matched to those elicited by MHV-A59 coronavirus brain infection, affected neuronal function in cultured primary mouse neocortical neurons. RESULTS: We evaluated how acute cytokine exposure affected neuronal excitability (propensity to fire action potentials), membrane properties, and action potential characteristics, as well as sensitivity to changes in extracellular calcium and magnesium (divalent) concentration. Neurovirulent cytokines increased spontaneous excitability and response to low divalent concentration by depolarizing the resting membrane potential and hyperpolarizing the action potential threshold. Evoked excitability was also enhanced by neurovirulent cytokines at physiological divalent concentrations. At low divalent concentrations, the change in evoked excitability was attenuated. One hour after cytokine removal, spontaneous excitability and hyperpolarization of the action potential threshold normalized but membrane depolarization and attenuated divalent-dependent excitability persisted. CONCLUSIONS: Coronavirus-associated cytokine exposure increases spontaneous excitability in neocortical neurons, and some of the changes persist after cytokine removal.

Cinacalcet inhibition of neuronal action potentials preferentially targets the fast inactivated state of voltage-gated sodium channels.

Voltage-gated sodium channel (VGSC) activation is essential for action potential generation in the brain. Allosteric calcium-sensing receptor (CaSR) agonist, cinacalcet, strongly and ubiquitously inhibits VGSC currents in neocortical neurons via an unidentified, G-protein-dependent inhibitory molecule. Here, using whole-cell patch VGSC clamp methods, we investigated the voltage-dependence of cinacalcet-mediated inhibition of VGSCs and the channel state preference of cinacalcet. The rate of inhibition of VGSC currents was accelerated at more depolarized holding potentials. Cinacalcet shifted the voltage-dependence of both fast and slow inactivation of VGSC currents in the hyperpolarizing direction. Utilizing a simple model, the voltage-dependence of VGSC current inhibition may be explained if the affinity of the inhibitory molecule to the channel states follows the sequence: fast-inactivated > slow-inactivated > resting. The state dependence of VGSC current inhibition contributes to the non-linearity of action potential block by cinacalcet. This dynamic and abundant signaling pathway by which cinacalcet regulates VGSC currents provides an important voltage-dependent mechanism for modulating central neuronal excitability.

SRT1720, a sirtuin 1 activator, attenuates organ injury and inflammation in sepsis.

BACKGROUND: Sepsis affects 800,000 patients in the United States annually with a mortality rate of up to 30%. Recent studies suggest that sepsis-associated metabolic derangements due to hypoxic tissue injury, impaired oxygen utilization, and mitochondrial dysfunction contribute to mortality. Sirtuin 1 (Sirt1) is a crucial modulator of energy metabolism during starvation states and has anti-inflammatory effects. Here, we hypothesized that SRT1720, a Sirt1 activator, could attenuate the severity of sepsis. MATERIALS AND METHODS: Male C57BL/6 mice (20-25 g) were subjected to cecal ligation and puncture (CLP) to induce sepsis. SRT1720 (5 or 20 mg/kg BW) or 10% dimethyl sulfoxide (vehicle) in 0.2-mL saline was injected intravenously at 5 h after CLP. Control animals were not subjected to any surgery. Blood and liver samples were harvested at 20 h after CLP for analysis. RESULTS: Administration of SRT1720 markedly reduced the serum levels of tissue injury markers (aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase) and renal injury markers (blood urea nitrogen and creatinine) in a dose-dependent manner after CLP. Furthermore, the levels of proinflammatory cytokines interleukin (IL)-1ß and IL-6 in the serum and liver were significantly inhibited by SRT1720 treatment after CLP. SRT1720 treatment resulted in a significantly decreased mRNA expression of inflammasome components (nucleotide oligomerization domain-like receptor protein 3, adapter apoptosis-associated speck-like protein containing caspase-recruitment domain, IL-1ß, and IL-18) in the liver, compared with the vehicle group. CONCLUSIONS: SRT1720 treatment attenuates multiorgan injury in septic mice. SRT1720 treatment also decreases the production of proinflammatory cytokines and reduces inflammasome activation. Thus, pharmacologic stimulation of Sirt1 may present a promising therapeutic strategy for sepsis.

Clinical and epidemiological characteristics of patients with acute drug intoxication admitted to ICU.

Background: Drug overdose continues to be the most common cause of acute poisoning worldwide. There has been a substantial increase in drug overdose incidence and prevalence over the past decade, probably as a result of the emergence of new synthetic designer drugs. The purpose of this study is to describe the clinical and epidemiological characteristics of patients with acute drug intoxication admitted to the Intensive Care Unit (ICU). Methods: A single center, prospective, observational study was conducted among all adult patients with clinical signs suggestive of acute drug intoxication admitted from the Emergency Department (ED) to ICU during a 6-month period (September to March). Results: Sixty-five patients were admitted. Their median age was 49 years (mean 48.2, range 20-72), and the majority were male (48, 74%). Median Sequential Organ Failure Assessment (SOFA) score on admission to ICU was 6 (mean 6, range 0-13). Fifty-five patients (85%) had a positive urine and/or serum toxicology screen. Most commonly detected substances were: opiates (18, 33%), cocaine (13, 24%), methadone (12, 22%), benzodiazepines (10, 18%), and marijuana (9, 16%). In 16 patients (29%), >1 substance was isolated. Twenty-three patients (35%) had negative urine toxicology screen. Ethyl alcohol was detected in the serum of 23 patients (35%). Five patients (8%) expired in ICU. Conclusion: Classic recreational drugs remain the most common substances involved in acute drug poisoning. More sensitive detection methods are warranted to identify new designer drugs of abuse such as synthetic cannabinoids.

Effects of time and day of admission on the outcome of critically ill patients admitted to ICU.

BACKGROUND: Studies have shown that patients admitted to hospitals on weekends and after-hours experience worse outcome than those admitted on weekdays and daytime hours. Although admissions of patients to intensive care units (ICUs) occur 24 hours a day, not all critical care units maintain the same level of staffing during nighttime, weekends, and holidays. This raises concerns in view of evidence showing that the organizational structure of an ICU influences the outcome of critically ill patients. The objective of this study is to evaluate the effects of day and time of admission to ICU on patients' outcome. METHODS: A single-center, prospective, observational study was conducted among all consecutive admissions to ICU in a community teaching hospital during a 4-month period. RESULTS: A total of 282 patients were admitted during the study period. Their mean age was 59.5 years (median 59, range 17-96), and the majority were male (157, 55.7%). Mean Acute Physiology and Chronic Health Evaluation (APACHE)-II score was 18.9 (median 33, range 1-45), and mean ICU length of stay was 3.1 days (median 2, range 1-19). Of the patients, 104 patients (36.9%) were admitted during weekends and 178 (63.1%) during weekdays. A total of 122 patients (43.3%) were admitted after-hours, constituting 68.5% of all admissions during weekdays. Fifty-six patients (19.9%) were admitted during daytime hours, representing 31.5% of all weekday admissions. Forty-five patients (15.9%) died in ICU. Compared to patients admitted on weekends, those admitted on weekdays had increased ICU mortality (operating room (OR)=0.437; 95% confidence interval=0.2054-0.9196; p=0.0293). CONCLUSION: Admissions to ICU during weekends were not independently associated with increased mortality. A linear relationship between weekdays and after-hours admissions to ICU with mortality was observed at our institution.

Prolonged cardiac arrest complicating a massive ST-segment elevation myocardial infarction associated with marijuana consumption.

Recreational substance use and misuse constitute a major public health issue. The annual rate of recreational drug overdose-related deaths is increasing exponentially, making unintentional overdose as the leading cause of injury-related deaths in the United States. Marijuana is the most widely used recreational illicit drug, with approximately 200 million users worldwide. Although it is generally regarded as having low acute toxicity, heavy marijuana usage has been associated with life-threatening consequences. Marijuana is increasingly becoming legal in the United States for both medical and recreational use. Although the most commonly seen adverse effects resulting from its consumption are typically associated with neurobehavioral and gastrointestinal symptoms, cases of severe toxicity involving the cardiovascular system have been reported. In this report, the authors describe a case of cannabis-associated ST-segment elevation myocardial infarction leading to a prolonged cardiac arrest.

Disseminated Cryptococcal Infection Resulting in Acute Respiratory Distress Syndrome (ARDS) as the Initial Clinical Presentation of AIDS.

Cryptococcosis is a cosmopolitan but rare opportunistic mycosis which is usually caused by Cryptococcus neoformans. Although the most common and worrisome disease manifestation is meningoencephalitis, pulmonary cryptococcosis has the potential to be lethal. The diagnosis of cryptococcal pneumonia is challenging, given its non-specific clinical and radiographic features. Respiratory failure leading to acute respiratory distress syndrome as a consequence of cryptococcal disease has been infrequently addressed in the literature. We herein present a case of disseminated cryptococcal infection leading to acute respiratory distress syndrome, refractory shock, and multiorgan dysfunction as the initial clinical manifestation in a patient who was newly diagnosed with acquired immunodeficiency syndrome.

Growth arrest-specific protein 6 protects against renal ischemia-reperfusion injury.

BACKGROUND: Renal injury caused by ischemia-reperfusion (I/R) often occurs after shock or transplantation. Growth arrest-specific protein 6 (Gas6) is a secreted protein that binds to the TAM-Tyro3, Axl, Mer-family tyrosine kinase receptors, which modulate the inflammatory response and activate cell survival pathways. We hypothesized that Gas6 could have a protective role in attenuating the severity of renal injury after I/R. MATERIALS AND METHODS: Adult mice were subjected to 45 min of bilateral renal ischemia. Recombinant mouse Gas6 (rmGas6, 5 µg per mouse) or normal saline (vehicle) was administered intraperitoneally 1 h before ischemia and all subjects were sacrificed at 23 h after I/R for blood and tissue analysis. The expression of protein and messenger RNA (mRNA) was assessed by Western blotting and quantitative polymerase chain reaction, respectively. RESULTS: Treatment with rmGas6 significantly decreased serum levels of creatinine and blood urea nitrogen by 29% and 27%, respectively, improved the renal histologic injury index, and reduced the apoptosis in the kidneys, compared with the vehicle. Renal mRNA levels of interleukin 1ß, interleukin 6, tumor necrosis factor α, keratinocyte-derived chemokine and macrophage inflammatory protein 2 were decreased significantly by 99%, 60%, 53%, 58%, and 43%, with rmGas6 treatment, respectively. After I/R, renal I-kappa-B α levels were reduced by 40%, whereas they returned to sham levels with rmGas6 treatment. The mRNA levels of inducible nitric oxide synthase and cyclooxygenase 2 were reduced by 79% and 70%, respectively, whereas the expression of cyclin D1 was increased by 2.1-fold in the rmGas6-treated group, compared with the vehicle. CONCLUSIONS: Gas6 suppresses the nuclear factor κB pathway and promotes cell proliferation, leading to the reduction of inflammation and protection of renal injury induced by I/R.

The Wide and Unpredictable Scope of Synthetic Cannabinoids Toxicity.

Drug use and abuse continue to be a large public health concern worldwide. Over the past decade, novel or atypical drugs have emerged and become increasingly popular. In the recent past, compounds similar to tetrahydrocannabinoid (THC), the active ingredient of marijuana, have been synthetically produced and offered commercially as legal substances. Since the initial communications of their abuse in 2008, few case reports have been published illustrating the misuse of these substances with signs and symptoms of intoxication. Even though synthetic cannabinoids have been restricted, they are still readily available across USA and their use has been dramatically increasing, with a concomitant increment in reports to poison control centers and emergency department (ED) visits. We describe a case of acute hypoxemic/hypercapnic respiratory failure as a consequence of acute congestive heart failure (CHF) developed from myocardial stunning resulting from a non-ST-segment elevation myocardial infarction (MI) following the consumption of synthetic cannabinoids.

Polymicrobial Bacteremia Involving Comamonas testosteroni.

Comamonas spp. are uncommon isolates in microbiology laboratories and have been rarely observed as an infectious agent in clinical practice. They have widespread environmental distribution and have been isolated from water, soil, and plants as well as from some hospital devices such as intravenous catheters and water contained in humidifier reservoirs used in respiratory treatment. The genus Comamonas originally contained the following species: acidovorans, testosteroni, kerstersii, terrigena, denitrificans, and nitrativorans. It now contains 17 species, while acidovorans spp. have been reclassified as Delftia acidovorans. In spite of its uncommon human pathogenesis, there are few reports on the aggressive manner of it as an opportunistic pathogen, mostly related to testosteroni spp. We present a case of polymicrobial bacteremia involving Comamonas testosteroni. The aim of this case report is to alert clinicians to the potential diagnosis of bloodstream infections caused by uncommon pathogens.

Cold-inducible RNA-binding protein is an important mediator of alcohol-induced brain inflammation.

Binge drinking has been associated with cerebral dysfunction. Ethanol induced microglial activation initiates an inflammatory process that causes upregulation of proinflammatory cytokines which in turn creates neuronal inflammation and damage. However, the molecular mechanism is not fully understood. We postulate that cold-inducible RNA-binding protein (CIRP), a novel proinflammatory molecule, can contribute to alcohol-induced neuroinflammation. To test this theory male wild-type (WT) mice were exposed to alcohol at concentrations consistent to binge drinking and blood and brain tissues were collected. At 5 h after alcohol, a significant increase of 53% in the brain of CIRP mRNA was observed and its expression remained elevated at 10 h and 15 h. Brain CIRP protein levels were increased by 184% at 10 h and remained high at 15 h. We then exposed male WT and CIRP knockout (CIRP(-/-)) mice to alcohol, and blood and brain tissues were collected at 15 h post-alcohol infusion. Serum levels of tissue injury markers (AST, ALT and LDH) were significantly elevated in alcohol-exposed WT mice while they were less increased in the CIRP(-/-) mice. Brain TNF-α mRNA and protein expressions along with IL-1ß protein levels were significantly increased in WT mice, which was not seen in the CIRP(-/-) mice. In cultured BV2 cells (mouse microglia), ethanol at 100 mM showed an increase of CIRP mRNA by 274% and 408% at 24 h and 48 h respectively. Corresponding increases in TNF-α and IL-1ß were also observed. CIRP protein levels were markedly increased in the medium, suggesting that CIRP was secreted by the BV2 cells. From this we conclude that alcohol exposure activates microglia to produce and secrete CIRP and possibly induce pro-inflammatory response and thereby causing neuroinflammation. CIRP could be a novel mediator of alcohol-induced brain inflammation.

Growth arrest-specific protein 6 attenuates neutrophil migration and acute lung injury in sepsis.

Sepsis is an acute inflammatory condition that can result in multiple organ failure and acute lung injury. Growth arrest-specific protein 6 (Gas6) is a broad regulator of the innate immune response involved with the nuclear factor κB signaling pathway. We hypothesized that Gas6 could have a protective role in attenuating the severity of acute lung injury and sepsis. Male mice were subjected to sepsis by cecal ligation and puncture (CLP) after which recombinant murine Gas6 (rmGas6; 5 µg/mouse) or normal saline (vehicle) was administered intravenously. Blood and lung tissues were collected at 20 h after CLP for various measurements. Treatment with rmGas6 significantly reduced serum levels of the injury markers aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, as well as proinflammatory cytokines interleukin 6 (IL-6) and IL-17, compared with the vehicle group (P < 0.05). The parenchyma of the lungs damaged by CLP was attenuated by rmGas6 treatment. Lung mRNA levels of tumor necrosis factor α, IL-1ß, IL-6, IL-17, and macrophage inflammatory protein 2 (MIP-2) were decreased by 60%, 86%, 82%, 93%, and 82%, respectively, with rmGas6 treatment as determined by real-time reverse transcriptase-polymerase chain reaction (P < 0.05). The degradation of IκB-α induced by CLP in the lungs was inhibited by rmGas6 treatment. The number of neutrophils and myeloperoxidase activity in the lungs were significantly reduced in the rmGas6 group. Moreover, rmGas6 reduced the in vitro migration of differentiated human promyelocytic HL60 cells by 64%. Finally, the 10-day survival rate of mice subjected to CLP was increased from 31% in the vehicle group to 67% in the rmGas6 group (P < 0.05). Thus, Gas6 has potential to be developed as a novel therapeutic agent to treat patients with sepsis and acute lung injury.