Reactivation of Epstein-Barr virus among intensive care patients: a prospective observational study.

PURPOSE: Herpesvirus reactivation has been documented among patients in the intensive care unit (ICU) and is associated with increased morbidity and mortality, particularly for cytomegalovirus (CMV). Epstein-Barr virus (EBV) has been poorly studied despite >95% of the population being seropositive. Our preliminary study suggested an association between EBV reactivation and increased morbidity and mortality. This study aimed to investigate this association among patients admitted to the ICU. METHODS: In this multicenter prospective study, polymerase chain reaction was performed to quantify EBV in patients upon ICU admission and then twice a week during their stay. Follow-up was 90 days. RESULTS: The study included 129 patients; 70 (54.3%) had EBV reactivation. On day 90, there was no difference in mortality rates between patients with and without reactivation (25.7% vs 15.3%, p = 0.22). Patients with EBV reactivation at admission had increased mortality compared with those without reactivation and those with later reactivation. EBV reactivation was associated with increased morbidity. Patients with EBV reactivation had fewer ventilator-free days at day 28 than those without reactivation (18 [1-22] vs. 21 days [5-26], p = 0.037) and a higher incidence of acute respiratory distress syndrome (34.3% vs. 17%, p = 0.04), infections (92.9% vs. 78%, p = 0.03), and septic shock (58.6% vs. 32.2%, p = 0.004). More patients with EBV reactivation required renal replacement therapy (30% vs. 11.9%, p = 0.02). EBV reactivation was also associated with a more inflammatory immune profile. CONCLUSION: While EBV reactivation was not associated with increased 90-day mortality, it was associated with significantly increased morbidity.

TRPV4 channel activation induces the transition of venous and arterial endothelial cells toward a pro-inflammatory phenotype.

The Transient Receptor Potential Vanilloid 4 (TRPV4) of endothelial cells contributes to many important functions including the regulation of Ca2+ homeostasis, cell volume, endothelial barrier permeability, and smooth muscle tone. However, its role in the transition of endothelial cells toward a pro-inflammatory phenotype has not been studied so far. Using both arterial and venous endothelial cells, we first show that the pharmacological activation of TRPV4 channels with GSK1016790A, a potent TRPV4 agonist, triggers robust and sustained Ca2+ increases, which are blocked by both TRPV4 antagonists HC067047 and RN9893. TRPV4 activation also triggers the actin cytoskeleton and adherens junction (VE-Cadherin) rearrangement in both arterial and venous endothelial cells and leads to rapid decreases of trans-endothelial electrical resistance. In addition to its effect on endothelial barrier integrity, TRPV4 activation selectively increases ICAM-1 surface expression in arterial and venous endothelial cells, due to the stimulation of ICAM-1 gene expression through the NF-κB transcription factor. TRPV4 channel activation also induced apoptosis of venous and arterial endothelial cells, while TRPV4 blockade reduced apoptosis, even in the absence of TRPV4 activation. As altered barrier integrity, increased adhesion molecule expression and apoptosis are hallmarks of the pro-inflammatory state of endothelial cells, our results indicate that TRPV4 channel activity can induce the transition of both venous and arterial endothelial cells toward a pro-inflammatory phenotype.

Alumina nanoparticles size and crystalline phase impact on cytotoxic effect on alveolar epithelial cells after simple or HCl combined exposures.

Applications using alumina nanoparticles (Al2O3 NPs) have incredibly increased in different fields of activity. In defense and aerospace fields, solid composite propellants use leads to complex combustion aerosols emissions containing high concentrations of Al2O3 NPs and hydrogen chloride gas (HCl). To better characterize potential hazard resulting from exposure to these aerosols, this study assesses cytotoxic effects of mixtures containing both compounds on human pulmonary alveolar epithelial cells (A549 cell line) after 24 h exposures. After all co-exposures cell viability was >80%. However co-exposures decrease normalized real-time cell index. Significant decreases of intracellular reduced glutathione pool were also observed after co-exposures to γ-10 nm or γ/δ-13 nm Al2O3 NPs and HCl. Co-incubations with γ/δ-13 nm or γ-500 nm Al2O3 particles and HCl induced significant DNA double-strand breaks increases. Moreover all co-exposures and HCl alone disrupted cell cycle (increased G1 phase cells). Transmission Electron Microscopy (TEM) observations revealed γ/δ-13 nm Al2O3NPs adsorption and internalization in cell cytoplasm only, suggesting indirect genotoxic effects. According to our results Al2O3 particles/HCl mixtures can induce cytotoxic effects and Al2O3 size and crystallinity are two main parameters influencing cytotoxic mechanisms.

Experimental Quantification of Delayed Radiation-Induced Organ Damage in Highly Irradiated Rats With Bone Marrow Protection: Effect of Radiation Dose and Organ Sensitivity.

The evolution of organ damage following extensive high-dose irradiation remains largely unexplored and needs further investigation. Wistar rats [with or without partial bone marrow protection (∼20%)] were irradiated at lethal gamma-ray doses (12, 14, and 16 Gy) and received antibiotic support. While total-body-irradiated rats did not survive, bone marrow protection (achieved by protecting hind limbs behind a lead wall) combined with antibiotic support allowed survival of 12-Gy and 14-Gy irradiated rats for more than 3 mo, with a late phase of body weight loss and altered clinical status. Histological analysis of radiation-induced damages in visceral organs (liver, kidney, and ileum), performed 64 and 104 d after high-dose body irradiation, indicates that the extent and the evolution of damage depend on both the irradiation dose and organ. A dose-related aggravation of lesions was observed in the liver and kidney but not in the ileum. In contrast to the liver, alterations in the kidney and ileum aggravate with time, emphasizing the need to develop new efficient countermeasures to protect both the gastrointestinal tract and kidney from late-occurring radiation effects. Specifically, the complex evolution of organ damage presented in this paper offers the possibility to explore and then validate specific therapeutic windows using candidate drugs targeted to each injured visceral organ.

The extent of irradiation-induced long-term visceral organ damage depends on cranial/brain exposure.

In case of high-dose radiation exposure, mechanisms controlling late visceral organ damage are still not completely understood and may involve the central nervous system. To investigate the influence of cranial/brain irradiation on late visceral organ damage in case of high-dose exposure, Wistar rats were irradiated at 12 Gy, with either the head and fore limbs or the two hind limbs protected behind a lead wall (head- and hind limbs-protected respectively), which allows long-term survival thanks to bone marrow protection. Although hind limbs- and head-protected irradiated rats exhibited similar hematopoietic and spleen reconstitution, a late body weight loss was observed in hind limbs-protected rats only. Histological analysis performed at this time revealed that late damages to liver, kidney and ileum were attenuated in rats with head exposed when compared to animals whose head was protected. Plasma measurements of inflammation biomarkers (haptoglobin and the chemokine CXCL1) suggest that the attenuated organ damage in hind limbs-protected rats may be in part related to reduced acute and chronic inflammation. Altogether our results demonstrate the influence of cranial/brain exposure in the onset of organ damage.

Intracochlear perfusion of leupeptin and z-VAD-FMK: influence of antiapoptotic agents on gunshot-induced hearing loss.

The therapeutic efficiency of cochlear infusion of two anti-apoptotic substances: a potent calpain inhibitor, leupeptin and a caspase inhibitor, z-VAD-FMK was evaluated in guinea pigs after a gunshot noise-induced trauma (170 dB SPL). A preliminary study showed that hair cell apoptosis appeared within 7 days of the noise trauma. For each animal, one of the cochleae was perfused directly starting 1 h after the trauma with leupeptin or z-VAD-FMK for 7 days via a mini-osmotic pump whereas the other cochlea was untreated. ABR threshold shifts were measured over a 14-day recovery period. The functional hearing study was supplemented by histological analysis. Two days after the trauma significant differences were observed between threshold shifts in the z-VAD-FMK-treated and the non-treated ears. Cochleograms showed that hair cell losses were significantly lower in z-VAD-FMK-treated ears. Regarding the leupeptin treatment, no significant difference between treated and non-treated ears was observed. This work indicates that early direct infusion of z-VAD-FMK into the cochlea accelerates hearing recovery and reduces hair cell loss after gunshot noise-induced trauma. These results suggest that the gunshot noise-induced trauma may involve the caspase pathway rather than the calpain pathway in the apoptotic process.

Therapeutic efficacy of magnesium after acoustic trauma caused by gunshot noise in guinea pigs.

CONCLUSIONS: The present findings show that magnesium administration can significantly reduce threshold shift 7 days after gunshot noise exposure. However, this improvement seems to be temporary, suggesting a probable advantage in prolonging the treatment. OBJECTIVE: To evaluate the therapeutic efficacy of magnesium administration after hearing loss induced by gunshot noise. MATERIAL AND METHODS: Forty-eight guinea pigs were exposed to an impulse noise (blank shot from a rifle; 170 or 176 dB SPL peak). The therapeutic efficacy of magnesium was evaluated by administering either the treatment or a placebo to the traumatized animals for 7 days, beginning 1 h after the trauma. Auditory function was explored for up to 14 days of recovery by recording the compound action potential in the round window. The functional study of hearing was supplemented by histological analysis. RESULTS: The threshold shifts of the 170-dB SPL group that received magnesium were significantly lower than those of controls after 2 and 7 days of recovery, but no significant difference was evidenced at 14 days in this group, nor at any time in the 176-dB SPL group. Animals treated with magnesium after the 176-dB SPL exposure had a significant reduction in hair cell loss in the basal region.