Proteolysis in septic shock patients: plasma peptidomic patterns are associated with mortality.

BACKGROUND: Uncontrolled proteolysis contributes to cell injury and organ dysfunction in animal models of circulatory shock. We investigated in humans the relationship between septic shock, proteolysis, and outcome. METHODS: Intensive care patients with septic shock (n=29) or sepsis (n=6) and non-hospitalised subjects (n=9) were recruited as part of the prospective observational trial 'ShockOmics' (ClinicalTrials.gov Identifier NCT02141607). A mass spectrometry-based approach was used to analyse the plasma peptidomes and the origin of circulating peptides from proteolysis in the enrolled subjects. RESULTS: Evidence of systemic proteolysis was indicated by a larger number of circulating peptides in septic shock patients, compared with septic patients and non-hospitalised healthy subjects. The peptide count and abundance in the septic shock patients were greater in patients who died (n=6) than in survivors (n=23), suggesting an association between magnitude of proteolysis and outcome. In silico analysis of the peptide sequences and of the sites of cleavage on the proteins of origin indicated a predominant role for serine proteases, such as chymotrypsin, and matrix metalloproteases in causing the observed proteolytic degradation. CONCLUSIONS: Systemic proteolysis is a novel fundamental pathological mechanism in septic shock. Plasma peptidomics is proposed as a new tool to monitor clinical trajectory in septic shock patients. CLINICAL TRIAL REGISTRATION: NCT02141607.

Usefulness of procalcitonin clearance as a prognostic biomarker in septic shock. A prospective pilot study.

OBJECTIVE: To evaluate procalcitonin clearance as a prognostic biomarker in septic shock. DESIGN: Prospective, observational pilot study. SETTING: Intensive care unit. PATIENTS: Patients admitted to the ICU due to septic shock and multiorgan dysfunction. INTERVENTIONS: Serum concentrations of procalcitonin were determined within 12h of onset of septic shock and multiorgan dysfunction (coinciding with admission to the ICU), and the following extractions were obtained after 24, 48 and 72h in patients who survived. DATA COLLECTED: Demographic data, Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score, data on the primary focus of infection, and patient outcome (ICU mortality). RESULTS: Procalcitonin clearance was higher in survivors than in non-survivors, with significant differences at 24h (73.9 [56.4-83.8]% vs 22.7 [-331-58.4], p<0.05) and 48h (81.6 [71.6-91.3]% vs -7.29 [-108.2-82.3], p<0.05). The area under the ROC curve was 0.74 (95%CI, 0.54-0.95, p<0.05) for procalcitonin clearance at 24h, and 0.86 (95%CI, 0.69-1.0, p<0.05) at 48h. CONCLUSIONS: ICU mortality was associated to sustained high procalcitonin levels, suggesting that procalcitonin clearance at 48h may be a valuable prognostic biomarker.

Potential energy surface for the H2O-H2 system.

In the present paper, we introduce a representation of the potential energy surface for the H(2)O...H(2) system based on orthogonal vectors, assuming that the two molecules are rigid. We represent the interaction potential by an expansion in real hyperspherical harmonics depending on the distance between the centers of mass of the two molecules and on four angles, which account for two contributions: an external one depending on the three angle variables which define the mutual orientation of the two molecules and an internal one expressed by the angle which describes the position of the oxygen atom in H(2)O with respect to the H(2)O...H(2) system. The surface was generated in the framework of the supermolecular approach, using the counterpoise-corrected interaction energies at the MP2/aug-cc-pVQZ level. Comparisons with other recent work are presented and features of the representation discussed.

Short-term effects of leptin on skeletal muscle protein metabolism in the rat.

We have examined the short-term effects of leptin on protein metabolism in the rat. Indeed, an intravenous leptin administration (100 microg/kg body weight), which resulted in no changes in circulating insulin in the time interval studied, induced a decrease in the incorporation of (14)C-leucine to (14)C-skeletal muscle protein. No changes were observed in relation to muscle protein degradation (either measured in vivo following isotope preloading or in vitro as tyrosine released into the incubation medium) and gene expression associated with the different proteolytic systems (cathepsin B, m-calpain and ubiquitin-proteasome system). The effects of leptin on amino acid incorporation into muscle protein do not seem to be direct because incubation of isolated EDL muscles in the presence of 10 microg/ml of leptin did not modify either the protein incorporation or the oxidation of (14)C-leucine. It may, therefore, be suggested that leptin is able to influence protein synthesis in skeletal muscle through the action of an unknown mediator.

Early c-Jun N-terminal kinase-dependent phosphorylation of activating transcription factor-2 is associated with degeneration of retinal ganglion cells.

Neuron death due to deprivation of target-derived neurotrophic factors depends on protein synthesis regulated by transcription factor activity. We investigated the content and phosphorylation of activating transcription factor 2 (ATF-2) in axon-damaged retinal ganglion cells of neonatal rats. In the retina of neonatal rats, the ATF-2 protein is predominantly located in the nucleus of the ganglion cells. A gradual loss of the immunoreactivity for ATF-2 occurred after explantation. ATF-2 is phosphorylated early after explantation, with a peak within 3 hours, preceding the peak of cell death that occurs at 18 hours. Both the phosphorylation of ATF-2 and ganglion cell death were blocked by treatment with an inhibitor of c-Jun N-terminal kinase (JNK), whereas an inhibitor of p38 reduced only slightly the rate of ganglion cell death with no effect upon phosphorylation of ATF-2. Inhibitors of phosphatidyl inositol 3 kinase (PI-3K), protein kinase C (PKC) or extracellular regulated kinase (ERK) had no effect. Finally, the inhibitor of JNK blocked the upregulation of both c-Jun and Hrk in the GCL after retinal explantation. The data show that phosphorylation of ATF-2 by JNK is associated with retinal ganglion cell death after axon damage.

Does the use of recombinant AAV5 in pulmonary gene therapy lead to lung damage?

This study investigated whether repeated administration of recombinant adeno-associated virus type 5 (rAAV5) to the airways induces inflammatory processes in the lungs of BALB/c-mice, with mechanical and histologic changes. Saline was instilled intratracheally in the control group, and rAAV5-green fluorescence protein (GFP) (4x10(11)particles) in the virus group (VR). These groups were subdivided into four subgroups: one dose analyzed 3 weeks later (VR1d3w) and two doses analyzed 1 (VR2d1w), 2 (VR2d2w) and 3 weeks (VR2d3w) after the second dose. Lung morphometry, mechanical parameters, airway responsiveness, rAAV5-GFP transduction and the expression of inflammatory cytokines were investigated. No significant differences in lung mechanics, airway responsiveness, and morphometry were observed. Re-administration of rAAV5 vector resulted in a decrease in GFP mRNA expression in the VR2d3w group. There was no evidence of inflammatory response or apoptosis in any group. rAAV5 did not induce an inflammatory process, mechanical or morphometric changes in the lungs. AAV5 may be an appropriate vector for lung gene therapy.