Larissa Constantino

Antioxidant treatment prevented late memory impairment in an animal model of sepsis.

Objective:Assess the effect of antioxidant treatment on late memory impairment and early hippocampus oxidative stress after cecal ligation and perforation. Subjects:Male Wistar rats. Interventions:Rats underwent sham operation or cecal ligation and perforation. Animals that underwent cecal ligation and perforation were divided into groups: 1) treated with basic support (50 mL/kg saline, 30 mg/kg ceftriaxone, and 25 mg/kg clindamycin every 6 hrs), 2) treated with basic support plus N-acetylcysteine (20 mg/kg N-acetylcysteine at 3, 6, 12, 18, and 24 hrs after cecal ligation and perforation), 3) treated with basic support plus deferoxamine (20 mg/kg deferoxamine at 3 and 24 hrs after cecal ligation and perforation), 4) treated with basic support plus N-acetylcysteine and deferoxamine, or 5) treated with N-acetylcysteine plus deferoxamine. Measurements and Main Results:On days 10 and 30 after surgery, the animals underwent behavioral tasks: inhibitory avoidance task, habituation to an open field, and continuous multiple-trials step-down inhibitory avoidance task. The sepsis group showed significantly decreased performance in latency retention compared with the sham group in the inhibitory avoidance task. In the open-field task, the sepsis group presented memory impairment after sepsis. In the continuous multiple-trials step-down inhibitory avoidance task, the sepsis group showed a significant increase in the number of training trials required to reach the acquisition criterion. All these memory impairments were prevented by N-acetylcysteine plus deferoxamine treatment, but not its isolate use. In addition, the combined use of antioxidants attenuated oxidative damage in hippocampus 6 hrs after sepsis induction. Conclusions:Antioxidant treatment prevented the development of late cognitive deficits in an animal model of sepsis.

Reversion of age-related recognition memory impairment by iron chelation in rats.

It is now generally accepted that iron accumulates in the brain during the ageing process. Increasing evidence demonstrate that iron accumulation in selective regions of the brain may generate free radicals, thereby possessing implications for the etiology of neurodegenerative disorders. In a previous study we have reported that aged rats present recognition memory deficits. The aim of the present study was to evaluate the effect of desferoxamine (DFO), an iron chelator agent, on age-induced memory impairment. Aged Wistar rats received intraperitoneal injections of saline or DFO (300mg/kg) for 2 weeks. The animals were submitted to a novel object recognition task 24h after the last injection. DFO-treated rats showed normal recognition memory while the saline group showed long-term recognition memory deficits. The results show that DFO is able to reverse age-induced recognition memory deficits. We also demonstrated that DFO reduced the oxidative damage to proteins in cortex and hippocampus. Thus, the present findings provide the first evidence that iron chelators might prevent age-related memory dysfunction.

Matrix Metalloproteinase-2 and Metalloproteinase-9 Activities are Associated with Blood–Brain Barrier Dysfunction in an Animal Model of Severe Sepsis

There is no description on the mechanisms associated with blood–brain barrier (BBB) disruption during sepsis development. Thus, we here determined changes in permeability of the BBB in an animal model of severe sepsis and the role of matrix metalloproteinase (MMP)-2 and MMP-9 in the dysfunction of the BBB. Sepsis was induced in Wistar rats by cecal ligation and perforation. BBB permeability was assessed using the Evans blue dye method. The content of MMP-2 and MMP-9 in the cerebral microvessels was determined by western blot. The activity of MMP-2 and MMP-9 was determined using zymography. An inhibitor of MMP-2 and MMP-9 or specific inhibitors of MMP-2 or MMP-9 were administered to define the role of MMPs on BBB permeability, brain inflammatory response, and sepsis-induced cognitive alterations. The increase of BBB permeability is time-related to the increase of MMP-9 and MMP-2 in the microvessels, both in cortex and hippocampus. Using an MMP-2 and MMP-9 inhibitor, or specific MMP-2 or MMP-9 inhibitors, the increase in the permeability of the BBB was reversed. This was associated with lower brain levels of interleukin (IL)-6 and lower oxidative damage. In contrast, only the inhibition of both MMP-9 and MMP-2 was able to improve acute cognitive alterations associated with sepsis. In conclusion, MMP-2 and MMP-9 activation seems to be a major step in BBB dysfunction, but BBB dysfunction seems not to be associated with acute cognitive dysfunction during sepsis development.

Comparison of CAM-ICU and ICDSC for the detection of delirium in critically ill patients focusing on relevant clinical outcomes.

PURPOSE Delirium is a frequent and serious problem in the intensive care unit (ICU) that is associated with increased mortality, prolonged mechanical ventilation, and prolonged hospital length of stay (LOS). The main objective of the present study was to compare and assess the agreement between the diagnosis of delirium obtained by the Confusion Assessment Method for the ICU (CAM-ICU) and Intensive Care Delirium Screening Checklist (ICDSC) in patients admitted to the ICU and their association with outcomes. METHODS Adult patients admitted to the ICU for more than 24 hours between May and November 2008 were included. Patients with a Richmond Agitation-Sedation Scale score of -4 to -5 for more than 3 days were excluded. Delirium was evaluated twice a day by the ICDSC and CAM-ICU. Patients were followed-up until ICU discharge or for a maximum of 28 days. RESULTS During the study period, 383 patients were admitted to the ICU and 162 (42%) were evaluated; delirium was identified in 26.5% of patients by CAM-ICU and in 34.6% by ICDSC. There was agreement in diagnosing delirium diagnosis between the 2 methods in 42 (27.8%) patients and in excluding delirium in 105 (64.8%) patients. The ICDSC was positive in 14 (8.6%) patients in whom CAM-ICU was negative. Delirium, diagnosed either by ICDSC or CAM-ICU assessments, was associated with both significantly increased hospital LOS (14.8 ± 8.3 vs 9.8 ± 6.4, P < .001; 15.3 ± 8.7 vs 10.5 ± 7.1, P < .001, respectively), mortality in the ICU (11.1% vs 5.8%, P < .001; 12.5% vs 2.5%, P = .022), and in the hospital (10.7% vs 5.6%, P < .001; 23.2% vs 10.9%, P = .047). In addition, patients with positive ICDSC presenting with negative CAM-ICU had similar outcomes as compared with those without delirium. CONCLUSION The findings of our study suggest that the CAM-ICU is better predictor of outcome when compared with ICDSC.

Plasma nitric oxide, endothelin-1, arginase and superoxide dismutase in pre-eclamptic women.

Aim:  The aim of this study was to determine several parameters of nitric oxide metabolism in pre‐eclamptic patients.

Oxidative Stress in Brain According to Traumatic Brain Injury Intensity

BACKGROUND The mechanisms of brain damage and neuroplasticity following traumatic brain injury (TBI) are complex and not completely understood. Thus, we investigated markers of oxidative stress in the central nervous system after mild and severe TBI in rats. MATERIAL AND METHODS Adult male wistar rats (five animals per group) submitted to mild (mTBI group) or severe TBI (sTBI Group) were sacrificed 30 min, 3, 6, or 12 h after the injury to quantify markers of oxidative damage in different brain regions. Levels of thiobarbituric acid reactive species and protein carbonyl in the cortex, hippocampus, striatum, and cerebellum of mTBI and sTBI groups were compared with the control group. RESULTS After mTBI, levels of protein oxidation were increased in all analyzed structures in several different times after injury. The increase in TBARS levels was not so consistent in mTBI. In contrast, sTBI did not induce a sustainable increase in oxidative damage markers in all analyzed structures. CONCLUSIONS Oxidative damage seemed to be inversely proportional to severity of traumatic brain injury.

Protective effects of guanosine against sepsis-induced damage in rat brain and cognitive impairment.

The development of cognitive impairment in sepsis is associated with neurotoxic effects caused by oxidative stress. We have assessed the effects of acute and extended administration of guanosine (GUA) on brain oxidative stress parameters and cognitive impairment in rats submitted to sepsis by cecal ligation and perforation (CLP). To achieve this goal, male Wistar rats underwent either sham operation or CLP with GUA. Rats subjected to CLP were treated with intraperitoneal injection of GUA (8 mg/kg after CLP) or vehicle. Twelve and 24 h after CLP, the rats were sacrificed, and samples from brain (hippocampus, striatum, cerebellum, prefrontal cortex and cortex) were obtained and assayed for thiobarbituric acid reactive species (TBARS) formation and protein carbonyls. On the 10th day, another group of rats was submitted to the behavioral tasks. GUA administration reduced TBARS and carbonyl levels in some brain regions between 12 and 24 h after CLP, and ameliorated cognitive impairment evaluated 10 days after CLP. Our data provide the first experimental demonstration that GUA was able to reduce the consequences of CLP-induced sepsis in rats, by decreasing oxidative stress parameters in the brain and recovering the memory impairment.

Sodium butyrate decreases the activation of NF-κB reducing inflammation and oxidative damage in the kidney of rats subjected to contrast-induced nephropathy

BACKGROUND Contrast-induced nephropathy (CIN) is associated with a combination of hypoxic and toxic renal tubular damage, renal endothelial dysfunction and altered intra-renal microcirculation. Recently, sodium butyrate (SB) has been focused on since it possesses anti-inflammatory activities. Thus, based on the lack of information on the effects of SB in acute kidney injury (AKI), we investigated the possible effects of SB after CIN in rats. METHODS Wistar rats were divided into three groups: (1 sham) control, (2 MI) AKI treated with contrast medium and (3 MI + SB) AKI plus SB. Six days after contrast administration, blood and kidney were removed for the determination of creatinine, interleukin (IL)-6 levels, oxidative damage parameters and histologic analyses. Nuclear factor kappa B (NF-κB), pIκBα and vasodilator-stimulated phosphoprotein (VASP) protein content were determined by immunoblotting. RESULTS After 6 days, the levels of creatinine increased significantly in the MI group, and this was attenuated using SB. SB treatment was associated with a decrease on the levels of lipid peroxidation, but not the protein oxidation, and IL-6 levels, as well as tubular damage. These effects are probably mediated, in part, by a decrease on the activation of NF-κB in the kidney, but not alteration in pVASP content. CONCLUSIONS The current experiment suggests that NF-κB induced an inflammatory response after CIN and SB could inhibit NF-κB expression protecting against CIN in rats.

Inflammatory and oxidative parameters in cord blood as diagnostic of early-onset neonatal sepsis: a case-control study.

Objective: To determine whether levels of interleukin (IL)-6, IL-10, and oxidative parameters in umbilical cord blood could contribute as an indicator of neonatal sepsis in recognized high-risk neonates. Design: Prospective, case-control study. Setting: Neonatal intensive care unit. Subjects: One hundred twenty consecutive preterm neonates who had at least one other risk factor for early-onset neonatal sepsis. Interventions: None. Measurements and Main Results: Umbilical cord blood samples were obtained for the determination of IL-6, IL-10, thiobarbituric acid reactive substances (TBARS), and protein carbonyls levels. Neonates were divided prospectively in two groups: control and septic. All parameters were higher in septic patients compared with control (IL-6 184.6 ± 72.7 vs. 58.9 ± 19.1, p < 0.01; IL-10 171.4 ± 59.2 vs. 79.9 ± 17.9, p < 0.01; TBARS 10.1 ± 2.8 vs. 4.2 ± 2.5, p < 0.01; protein carbonyls 2.4 ± 1.2 vs. 1.15 ± 0.5, p < 0.01, respectively, septic vs. control). In addition, these parameters were higher in the subgroup of culture-positive septic patients compared with control. IL-6 and TBARS had equivalent areas under the receiver operator characteristic (ROC) curve (0.88); IL-10 (0.80) and protein carbonyls (0.73) had lower areas. Multivariate logistic regression comparing IL-6 and TBARS in terms of the relative risk for neonatal sepsis demonstrated that TBARS was a better predictor, being independently associated with neonatal sepsis. Conclusion: Our findings demonstrated that cord blood IL-6, IL-10, and oxidative stress markers were significantly higher in infants with neonatal sepsis, and only TBARS levels were independently related to the development of neonatal sepsis in our sample.

Behavioral deficits in sepsis-surviving rats induced by cecal ligation and perforation

Sepsis and its complications are the leading causes of mortality in intensive care units, accounting for 10-50% of deaths. Intensive care unit survivors present long-term cognitive impairment, including alterations in memory, attention, concentration, and/or global loss of cognitive function. In the present study, we investigated behavioral alterations in sepsis-surviving rats. One hundred and ten male Wistar rats (3-4 months, 250-300 g) were submitted to cecal ligation and puncture (CLP), and 44 were submitted to sham operation. Forty-four rats (40%) survived after CLP, and all sham-operated animals survived and were used as control. Twenty animals of each group were used in the object recognition task (10 in short-term memory and 10 in long-term memory), 12 in the plus-maze test and 12 in the forced swimming test. Ten days after surgery, the animals were submitted individually to an object recognition task, plus-maze and forced swimming tests. A significant impairment of short- and long-term recognition memory was observed in the sepsis group (recognition index 0.75 vs 0.55 and 0.74 vs 0.51 for short- and long-term memory, respectively (P < 0.05). In the elevated plus-maze test no difference was observed between groups in any of the parameters assessed. In addition, sepsis survivors presented an increase in immobility time in the forced swimming test (180 vs 233 s, P < 0.05), suggesting the presence of depressive-like symptoms in these animals after recovery from sepsis. The present results demonstrated that rats surviving exposure to CLP, a classical sepsis model, presented recognition memory impairment and depressive-like symptoms but not anxiety-like behavior.