Central angiotensin-(1-7) attenuates hypoglycemia in sepsis-like conditions via reducing systemic and hepatic inflammation.

Sepsis is understood as the result of initiating systemic inflammation derived from an inadequate host response against pathogens. In its acute phase, sepsis is marked by an exacerbated reaction to infection, tissue damage, organ failure, and metabolic dysfunction. Among these, hypoglycemia, characterized by disorders of the gluconeogenesis pathway, is related to one of the leading causes of mortality in septic patients. Recent research has investigated the involvement of sympathetic efferent neuroimmune pathways during systemic inflammation. These pathways can be stimulated by several centrally administered drugs, including Angiotensin-(1-7) (Ang-(1-7)). Therefore, the present study aims to evaluate the effects of central treatment with Ang-(1-7) on hypoglycemia during endotoxemia. For this, male Wistar Hannover rats underwent stereotaxic surgery for intracerebroventricular (i.c.v.) administration of Ang-(1-7) and cannulation of the jugular vein for lipopolysaccharide (LPS) injection. Our results demonstrate that LPS was capable of inducing hypoglycemia and that prior central treatment with Ang-(1-7) attenuated this effect. Our data also show that Ang-(1-7) reduced plasma concentrations of TNF-α, IL-1ß, IL-6, and nitric oxide, in addition to the decrease and increase of hepatic IL-6 and IL-10 respectively, in animals subjected to systemic inflammation by LPS, resulting in the reduction of systemic and hepatic inflammation, thus attenuating the deleterious effects of LPS on phosphoenolpyruvate carboxykinase protein content. In summary, the data suggest that central treatment with Ang-(1-7) attenuates hypoglycemia induced by endotoxemia, probably through anti-inflammatory action, leading to reestablishing hepatic gluconeogenesis.

Nitric oxide storage levels modulate vasodilation and the hypotensive effect induced by photobiomodulation using an aluminum gallium arsenide (AlGaAs) diode laser (660 nm).

The aim of this study was to evaluate the participation of nitric oxide (NO) in the hypotensive and vasorelaxation effect induced by PBM using an aluminum gallium arsenide (AlGaAs) diode laser (660 nm). Male Wistar rats were treated with the inhibitor of nitric oxide synthase (L-NAME). A red laser (660 nm; 63 J/cm2; 56 s/point) was applied to the abdominal region at six different points. Thoracic aorta was dissected for vascular reactivity study, and a laser (660 nm; 96 J/cm2; 56 s) was applied after incubation with the NO donor DETA-NO, PBS, or hydroxicobalamin. Endothelial cells (HUVEC) were treated with DETA-NO or CuSO4, and then, PBM (63 J/cm2) was applied, and the nitric oxide was detected. Hypertensive L-NAME rats did not exhibit a decrease in blood pressure after PBM. PBM promoted vasodilation in the aorta isolated from normotensive rats, and less effect in the aorta of L-NAME rats and the addition of the NO donor, DETA-NO, promoted greater vasodilation by PBM in the aorta of L-NAME rats. In endothelial cells, an increase in NO, after PBM, was detected; however, with the addition of CuSO4, which catalyzes the decomposition of NO storage, there was no detection of NO after PBM. The results of this study demonstrate that the hypotensive and vasodilatory effect of PBM with a red laser at 660 nm is modulated by the release of nitric oxide from the storage.

Central angiotensin-(1-7) attenuates systemic inflammation via activation of sympathetic signaling in endotoxemic rats.

Angiotensin-(1-7) [Ang-(1-7)] is an angiotensin-derived neuropeptide with potential anti-hypertensive and anti-inflammatory properties. However, a possible action of Ang-(1-7) in neuroimmune interactions to regulate inflammatory response has not been explored. Thus, the aim of this study was to determine whether the intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation via sympathetic efferent circuits. Wistar male rats received systemic administration of lipopolysaccharide (LPS) (1.5 mg/Kg). Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of splenic norepinephrine and attenuated tumor necrosis factor (TNF) and nitric oxide (NO), but increased interleukin-10 (IL-10), levels in the serum, spleen, and liver in endotoxemic rats. Furthermore, 6-hydroxydopamine-induced chemical sympathectomy (100 mg/Kg, intravenous) or i.c.v. administration of Mas receptor antagonist A779 (3 nmol in 2 µL) abolished the anti-inflammatory effects of central Ang-(1-7) injection. Moreover, this treatment did not alter the plasmatic LPS-induced corticosterone and vasopressin. The administration of Ang-(1-7) reverted the low resistance in response to catecholamines of rings of thoracic aorta isolated from endotoxemic rats, treated or not, with this peptide by a mechanism dependent on the regulation of NO released from perivascular adipose tissue. Together, our results indicate that Ang-(1-7) regulates systemic inflammation and vascular hyporesponsiveness in endotoxemia via activation of a central Mas receptors/sympathetic circuits/norepinephrine axis and provide novel mechanistic insights into the anti-inflammatory Ang-(1-7) properties.

[Pharmacotherapy and analysis of gaseous mediators in hypertensive patients]. / Farmacoterapia e análise de mediadores gasosos em pacientes hipertensos.

OBJECTIVE: To evaluate the effect of using antihypertensive classes of drugs of the calcium channel antagonists and inhibitors of angiotensin-converting enzyme in plasma concentrations of hydrogen sulfide and nitric oxide in patients with hypertension. METHODS: Cross-sectional study with quantitative approach conducted with hypertensive patients in use of antihypertensive classes of drugs: angiotensin-converting enzyme inhibitors or calcium channel antagonists. RESULTS: It was found that the concentration of plasma nitric oxide was significantly higher in hypertensive patients that were in use of angiotensin-converting enzyme inhibitors (p<0.03) and the hydrogen sulphide concentration was significantly higher in hypertensive plasma in use of calcium channel antagonists (p<0.002). CONCLUSION: The findings suggest that these medications have as additional action mechanism the improvement of endothelial dysfunction by elevate plasma levels of vasodilatory substances.

Cholecystokinin protects rats against sepsis induced by Staphylococcus aureus.

Staphylococcus aureus is a Gram-positive bacteria described as an important causative agent of sepsis. The contact between host leukocytes and bacteria activates the innate immune response. Nitric oxide, tumor necrosis factor (TNF)-α and interleukin (IL)-1ß play a key role in increasing microbicidal activity and controlling cell influx into infectious focus. Contrarily, IL-10 acts as an anti-inflammatory cytokine and bacterial killing suppressor. Immunoregulatory properties have also been attributed to hormones, including cholecystokinin (CCK). CCK protects cardiovascular function and inhibits the inflammatory response induced by lipopolysaccharide, product derived from Gram-negative bacteria. Nevertheless, the role of CCK during Gram-positive infection remains a literature gap. Our aims were to investigate whether CCK protects rats against bacterial dissemination during sepsis induced by S. aureus. We determined whether CCK modulates local and systemic inflammatory response, as well as the cell migration into the infectious focus and the bactericidal capacity of leukocytes. Our results revealed that proglumide (nonselective CCK receptor antagonist) pretreated rats showed higher bacterial counts in blood and peritoneal lavage fluid (PLF) and reduced TNF-α and IL-10 levels in PLF. Moreover, the dissemination of S. aureus may be related to the failure of neutrophil and macrophage migration into the peritoneal cavity. Also, CCK improved the phagocytic and bactericidal ability of these inflammatory cells. Noteworthy is that the adoptive transfer of CCK-treated neutrophils and macrophages in septic rats improved immune defense, reducing bacterial number in blood and PLF. All together, our study clearly demonstrates an important protective role of CCK against sepsis induced by S. aureus.

Cholecystokinin inhibits inducible nitric oxide synthase expression by lipopolysaccharide-stimulated peritoneal macrophages.

Cholecystokinin (CCK) was first described as a gastrointestinal hormone. However, apart from its gastrointestinal effects, studies have described that CCK also plays immunoregulatory roles. Taking in account the involvement of inducible nitric oxide synthase- (iNOS-) derived NO in the sepsis context, the present study was undertaken to investigate the role of CCK on iNOS expression in LPS-activated peritoneal macrophages. Our results revealed that CCK reduces NO production and attenuates the iNOS mRNA expression and protein formation. Furthermore, CCK inhibited the nuclear factor- (NF-) κB pathway reducing IκBα degradation and minor p65-dependent translocation to the nucleus. Moreover, CCK restored the intracellular cAMP content activating the protein kinase A (PKA) pathway, which resulted in a negative modulatory role on iNOS expression. In peritoneal macrophages, the CCK-1R expression, but not CCK-2R, was predominant and upregulated by LPS. The pharmacological studies confirmed that CCK-1R subtype is the major receptor responsible for the biological effects of CCK. These data suggest an anti-inflammatory role for the peptide CCK in modulating iNOS-derived NO synthesis, possibly controlling the macrophage activation through NF-κB, cAMP-PKA, and CCK-1R pathways. Based on these findings, CCK could be used as an adjuvant agent to modulate the inflammatory response and prevent systemic complications commonly found during sepsis.

Oxytocin affects nitric oxide and cytokine production by sepsis-sensitized macrophages.

BACKGROUND/AIM: Oxytocin (OXT) secretion during cecal ligation puncture (CLP)-induced sepsis has not yet been examined. Although immune properties have been attributed to OXT, its effect on CLP-sensitized macrophages has never been investigated. We analyzed OXT secretion during CLP and its effect in CLP-sensitized macrophage cultures. METHODS: Male Wistar rats were decapitated 4, 6 or 24 h after CLP surgery or sham operation and blood, brain and neurohypophyses were collected for OXT measurements. In another set of animals we studied the effect of OXT on nitrite, tumor necrosis factor (TNF-α), interleukin (IL)-1ß and IL-10 production of peritoneal macrophages harvested at 6 and 24 h after CLP. RESULTS: In the early phase of sepsis (4-6 h), OXT levels increased in plasma and decreased in hypothalamus and neurohypophysis. In the late phase (24 h), plasma and neurohypophyseal levels remained basal. In the paraventricular, the OXT content remained low, but in the supraoptic increased. Macrophages of the early phase of sepsis pretreated with OXT and stimulated with lipopolysaccharide showed decreased nitrite, TNF-α and IL-1ß levels, but no alteration in IL-10 production. In the late phase, they showed reduction only on IL-1ß. CONCLUSIONS: OXT secretion during sepsis may represent a neuroendocrine response contributing to the overall host response to infection by decreasing the proinflammatory response and oxidative stress.

[Examination of the oral cavities of patients with cancer: clinical evaluation and indirect measurement of the nitric oxide level]. / Exame da cavidade bucal de pacientes com câncer: avaliação clínica e dosagem indireta de óxido nítrico.

This observational study aimed to verify the association between the clinical state of the oral cavity (based on the Index of Decayed, Missing, and Filled Teeth and the Simplified Oral Hygiene Index) and the indirectly determined nitric oxide level in patients with oncologic and hematologic diseases. This study included 20 hospitalized patients who were in the evaluation phase prior to starting chemotherapy and who had been diagnosed with leukemia (35%), lymphoma (50%) or myeloma (15%). Fifty percent of these patients had normal oral health (no injury or trauma), and most had satisfactory (35%) or typical (35%) hygiene, but 30% had poor or very poor hygiene. The indirectly measured levels of nitric oxide ranged from 13.34 to 257. The nitric oxide level was not associated with other parameters, and there was great variability in its level. Further studies are necessary given the potential of using this indicator in the early detection of oral diseases.

Inhaled molecular hydrogen reduces hippocampal neuroinflammation, glial reactivity and ameliorates memory impairment during systemic inflammation.

Sepsis is associated with numerous physiological and biochemical abnormalities that result in a life-threatening condition. The involvement of the Central Nervous System (CNS) during sepsis has received considerable attention, especially the hippocampus which plays a key role in the learning and memory processes. The increased interest in this limbic region during systemic inflammation (SI) is related to the number of sepsis survivor patients who have cognitive impairments. A single injection of lipopolysaccharide (LPS)-induced systemic inflammation is the most commonly used murine endotoxemia model because it replicates several pathophysiological changes observed in severe sepsis. Molecular hydrogen (H2) has been used as an anti-inflammatory therapeutic strategy to prevent neuroinflammation. However, the mechanisms by which inhaled H2 mitigate memory loss during SI remains unknown. To understand how H2 acts in the hippocampus, the current study focused on specific mechanisms that may be involved in reducing neuroinflammation in rats during SI. We hypothesized that inhaled H2 decreases LPS-induced hippocampal pro-inflammatory cytokines surges and this effect is associated with reduced memory loss. Using different and integrative approaches, i.e., from hippocampal cells electrophysiology to animal behavior, we report that inhaled H2 decreased LPS-induced peripheral and hippocampal inflammation, decreased microglial and astrocytic activation, lessen memory loss without affecting long-term potentiation (LTP). To our knowledge, this is the first evidence showing that inhaled H2 reduces hippocampal microglial and glial cells inflammation, which may be associated with a reduced memory impairment induced by SI.

Angiotensin-(1-7) improves tail skin heat loss and increases the survival of rats with polymicrobial sepsis.

Sepsis is a serious syndrome, characterized by the excessive release of inflammatory mediators and thermoregulatory changes, being fever the most common sign. However, despite the importance of Angiotensin (Ang)-(1-7) in controlling the inflammation, the role of the peptide in the febrile response and mortality in animals submitted to experimental model of sepsis is still not clear. In this way, we evaluate the effect of continuous infusion of Ang-(1-7) in inflammatory response, thermoregulation and in mortality of Wistar male rats submitted to colonic ligation puncture (CLP). Before CLP surgery, the infusion pumps (Ang-(1-7), 1.5 mg/mL or saline) were inserted into the abdominal cavity and maintained for 24 h. CLP rats showed a febrile response starting from 3 h after and persisted until the 24th hour of experiment. Continuous treatment with Ang-(1-7) attenuated the febrile response and reestablished the euthermia 11 h after CLP, until the end of experiment, which coincided with an increased heat loss index (HLI). This effect was associated with a decrease in production of pro-inflammatory mediators in liver, white adipose tissue (WAT) and hypothalamus. Moreover, an increase in norepinephrine (NE) content in interscapular brown adipose tissue (iBAT) was observed in CLP animals, which was attenuated with treatment with Ang-(1-7), and decreased mortality in CLP animals treated with Ang-(1-7). Taken together, the present study demonstrates that continuous infusion treatment with Ang-(1-7) can promote a global anti-inflammatory effect, reestablishing the tail skin heat loss as a key thermo-effector function, resulting in an increased survival of animals submitted to experimental sepsis.

Trends in scientific editing and good research practices: what do researchers-nurses know?

OBJECTIVE: To verify researchers-nurses' knowledge about trends in scientific publishing and good research practices. METHOD: A descriptive study carried out through an online survey with 197 nurses holding master's and/or doctoral degrees from all Brazilian regions. To raise knowledge, a validated, self-administered and anonymous questionnaire with 18 questions on the subject was used. Descriptive and inferential analyzes were performed on researchers' scores (Mann-Whitney test). RESULTS: Among the specific questions, the mean of correct answers was 7.1: 6.4 for master's and 7.4 for doctoral degree holders. There was a significant difference in the mean of correct answers between masters and doctors (p = 0.025), and between productivity scholarship holders and non-scholarship holders (p = 0.021), according to mean difference tests. Questions about predatory editorial practices were those in which researchers had the worst knowledge. CONCLUSION: We identified that, regardless of the education level (master's or doctoral degree), nurses have little knowledge about the topics studied, which can compromise the quality of production and the scientific vehicles used to disseminate this knowledge.

Development, implementation, and assessment of a distance module in endocrine physiology.

This study aimed to develop, implement, and assess a distance module in endocrine physiology in TelEduc for undergraduate nursing students from a public university in Brazil, with a sample size of 44 students. Stage 1 consisted of the development of the module, through the process of creating a distance course by means of the Web. Stage 2 was the planning of the module's practical functioning, and stage 3 was the planning of student evaluations. In the experts' assessment, the module complied with pedagogical and technical requirements most of the time. In the practical functioning stage, 10 h were dedicated for on-site activities and 10 h for distance activities. Most students (93.2%) were women between 19 and 23 yr of age (75%). The internet was the most used means to remain updated for 23 students (59.0%), and 30 students (68.2%) accessed it from the teaching institution. A personal computer was used by 23 students (56.1%), and most of them (58.1%) learned to use it alone. Access to a forum was more dispersed (variation coefficient: 86.80%) than access to chat (variation coefficient: 65.14%). Average participation was 30 students in forums and 22 students in the chat. Students' final grades in the module averaged 8.5 (SD: 1.2). TelEduc was shown to be efficient in supporting the teaching-learning process of endocrine physiology.

Study of thermo-regulation as a worsening marker of experimental sepsis in an animal model.

OBJECTIVE: to analyze variations in body temperature and in plasma nitrate and lactate concentrations in rats submitted to the experimental sepsis model. METHOD: a total of 40 rats divided equally into five groups. The induction of endotoxemia was performed with intravenous administration of lipopolysaccharide, 0.5 mg/Kg, 1.5 mg/Kg, 3.0 mg/Kg, and 10 mg/Kg, respectively. The control group received 0.5 mL of saline solution. The experiment lasted six hours, with evaluations performed at 0 (baseline data), 2nd, 4th, and 6thhours. RESULTS: The animals that received doses up to 3.0 mg/kg showed a significant increase in body temperature compared to the group with 10 mg/kg, which showed a decrease in these values. The increase in plasma nitrate and lactate concentrations in the groups with lipopolysaccharide was significantly higher than in the group that received the saline solution and was correlated with the increase in body temperature. CONCLUSION: the variations in body temperature observed in this study showed the dose-dependent effect of lipopolysaccharide and were correlated with the increase in the concentrations of nitrate and plasma lactate biomarkers. The implications of this study are the importance of monitoring body temperature, together with the assessment of these pathophysiological markers, which suggest worsening in the prognosis of sepsis.

Simvastatin Prevents Long-Term Cognitive Deficits in Sepsis Survivor Rats by Reducing Neuroinflammation and Neurodegeneration.

Sepsis-associated encephalopathy causes brain dysfunction that can result in cognitive impairments in sepsis survivor patients. In previous work, we showed that simvastatin attenuated oxidative stress in brain structures related to memory in septic rats. However, there is still a need to evaluate the long-term impact of simvastatin administration on brain neurodegenerative processes and cognitive damage in sepsis survivors. Here, we investigated the possible neuroprotective role of simvastatin in neuroinflammation, and neurodegeneration conditions of brain structures related to memory in rats at 10 days after sepsis survival. Male Wistar rats (250-300 g) were submitted to cecal ligation and puncture (CLP, n = 42) or remained as non-manipulated (naïve, n = 30). Both groups were treated (before and after the surgery) by gavage with simvastatin (20 mg/kg) or an equivalent volume of saline and observed for 10 days. Simvastatin-treated rats that survived to sepsis showed a reduction in the levels of nitrate, IL1-ß, and IL-6 and an increase in Bcl-2 protein expression in the prefrontal cortex and hippocampus, and synaptophysin only in the hippocampus. Immunofluorescence revealed a reduction of glial activation, neurodegeneration, apoptosis, and amyloid aggregates confirmed by quantification of GFAP, Iba-1, phospho Ser396-tau, total tau, cleaved caspase-3, and thioflavin-S in the prefrontal cortex and hippocampus. In addition, treated animals presented better performance in tasks involving habituation memory, discriminative, and aversive memory. These results suggest that statins exert a neuroprotective role by upregulation of the Bcl-2 and gliosis reduction, which may prevent the cognitive deficit observed in sepsis survivor animals.

Inflammatory markers in the hippocampus after audiogenic kindling.

Here, we investigated the participation of pro and anti-inflammatory cytokines in the spread of repeated audiogenic seizures from brainstem auditory structures to limbic areas, including the hippocampus. We used Wistar Audiogenic Rats (WARs) and Wistars submitted to the audiogenic kindling protocol with a loud broad-band noise. We measured pro and anti-inflammatory cytokines and nitrate levels in the hippocampus of stimulated animals. Our results show that all WARs developed audiogenic seizures that evolved to limbic seizures whereas seizure-resistant controls did not present any seizures. However, regardless of seizure severity, we did not observe differences in the pro inflammatory cytokines IL-1ß, IL-6, TNF-α and IFN-α or in the anti-inflammatory IL-10 in the hippocampi of audiogenic and resistant animals. We also did not find any differences in nitrate content. Our data indicate that the spread of seizures during the audiogenic kindling is not dependent on hippocampal release of cytokines or oxidative stress, but the severity of brainstem seizures will be higher in animals with higher levels of cytokines and the oxidative stress marker, nitrate.

Desempenho do óxido nítrico na sepse: uma revisão de escopo / Desempeño del óxido nítrico en la sepsis: una revisión de alcance / Performance of nitric oxide in sepsis: a scoping review

Resumo Objetivo Mapear as evidências disponíveis sobre as ações do óxido nítrico na fisiopatologia da sepse e sua relação com a gravidade de pacientes sépticos. Método Revisão de escopo de acordo com a metodologia do Joanna Briggs Institute. Realizou-se busca por estudos que evidenciaram as ações do óxido nítrico na sepse e se o seu aumento está associado à gravidade de pacientes sépticos. Dois revisores independentes fizeram o mapeamento das informações utilizando um instrumento de extração de dados previamente elaborado. Os dados foram analisados quanto à sua relevância, sendo posteriormente extraídos e sintetizados. Resultados De 1342 estudos, 11 foram incluídos na revisão. O primeiro foi publicado em 2017 e o último, em 2022. A maioria foi desenvolvida nos Estados Unidos, na China e na Alemanha. Os estudos apresentaram informações referentes as ações do óxido nítrico, sintetizando sua biodisponibilidade e os inibidores endógenos relacionados a sua produção, além de abordarem a relação do óxido nítrico com a gravidade da sepse. Conclusão A produção de óxido nítrico fisiológico durante a sepse atua como protetor vascular, principalmente na microcirculação, porém, em altas concentrações, contribui para a disfunção vascular, que subverte a fisiologia da regulação da pressão arterial, causando profunda vasodilatação e hipotensão refratária e aumentando a gravidade de pacientes sépticos.

Resumen Objetivo Mapear las evidencias disponibles sobre las acciones del óxido nítrico en la fisiopatología de la sepsis y su relación con la gravedad de pacientes sépticos. Métodos Revisión de alcance de acuerdo con la metodología del Joanna Briggs Institute. Se realizó una búsqueda de estudios que evidenciaron las acciones del óxido nítrico en la sepsis y si su aumento estaba asociado a la gravedad de pacientes sépticos. Dos revisores independientes hicieron el mapeo de la información utilizando un instrumento de extracción de datos previamente elaborado. Los datos se analizaron respecto a su relevancia, para luego extraerlos y sintetizarlos. Resultados De 1342 estudios, se incluyeron 11 en la revisión. El primero fue publicado en 2017 y el último en 2022. La mayoría se realizó en Estados Unidos, China y Alemania. Los estudios presentaron información referente a las acciones del óxido nítrico, sintetizando su biodisponibilidad y los inhibidores endógenos relacionados con su producción, además de abordar la relación del óxido nítrico con la gravedad de la sepsis. Conclusión La producción de óxido nítrico fisiológico durante la sepsis actúa como protector vascular, principalmente en la microcirculación. Sin embargo, en altas concentraciones, contribuye a la disfunción vascular, que subvierte la fisiología de la regulación de la presión arterial, causa una profunda vasodilatación e hipotensión refractaria y aumenta la gravedad de pacientes sépticos. Registro da revisão de escopo no Open Science Framework: https://doi.org/10.17605/OSF.IO/MXDK2

Abstract Objective Map the available evidence on the actions of nitric oxide in the pathophysiology of sepsis and its relationship with the severity of sepsis in patients. Method Scoping review following the Joanna Briggs Institute methodology. A search was carried out for studies that highlighted the actions of nitric oxide in sepsis, informing whether its increase is associated with the severity of sepsis in patients. Two independent reviewers mapped the information using a previously designed data extraction instrument. The data was analyzed for its relevance and then extracted and synthesized. Results Eleven of 1342 studies were included in the review. The first of them was published in 2017 and the last in 2022. Most of them were developed in the USA, China, and Germany. Studies have reported the actions and bioavailability of nitric oxide and endogenous inhibitors related to its production, and related nitric oxide to the severity of sepsis. Conclusion The physiological production of nitric oxide during sepsis acts as a vascular protector, mainly in the microcirculation but contributes to vascular dysfunction in high concentrations, subverting the regulation of blood pressure, causing deep vasodilation and refractory hypotension, and increasing the severity of sepsis in patients. Registration of the scoping review in the Open Science Framework: https://doi.org/10.17605/OSF.IO/MXDK2

Role of ghrelin on growth hormone/insulin-like growth factor-1 axis during endotoxemia.

OBJECTIVE: To investigate the anti-inflammatory property of ghrelin treatment on the Growth Hormone (GH)/Insulin-like Growth Factor-I (IGF-1) axis in Wistar rats that have undergone endotoxemia. DESIGN: In this randomized animal study, lipopolysaccharide (LPS) (5 mg/kg; intraperitoneal) was administered to induce endotoxemia, and ghrelin (15 nmol/kg; endovenous) was injected simultaneously. Blood and liver samples were collected 2 h, 6 h and 12 h after LPS administration for analysis. MEASUREMENTS: Tumor necrosis factor alpha (TNF-α), interleukin (IL)-1, beta (IL-1ß), and IL-6 from both blood and liver were determined by ELISA assay. Serum nitrate was determined by chemiluminescense. Growth hormone receptor (GHR) and growth hormone secretagogue receptor 1a (GHSR-1a) were determined by western blotting. GHR mRNA and IGF-1 mRNA were determined by RT-PCR. RESULTS: LPS administration induced a decrease in IGF-1 and GH serum levels, characterizing GH/IGF-1 axis disruption. Ghrelin treatment attenuated the decrease of serum levels of IGF-1 as well as the increase of TNF-α, IL-1ß, IL-6 and nitrate induced by LPS. The increase of induced GHSR-1a protein expression seen in the LPS group after 2 h remained until 6 h after ghrelin treatment. However, attenuation of the circulating IGF-1 decrease by ghrelin treatment was not accompanied by changes in GHR protein expression nor GHR and IGF-1 gene expression. CONCLUSION: Ghrelin was able to attenuate changes in the GH/IGF-1 axis observed during systemic inflammation, which may be due to the modulation of pro-inflammatory mediators release.

Participation of iNOS-derived NO in hypothalamic activation and vasopressin release during polymicrobial sepsis.

Clinical and experimental studies with LPS injection have shown an increase in vasopressin (AVP) secretion in the early phase of severe sepsis, which is subsequently reduced despite persistent hypotension. The aim of this study was to evaluate the role of inducible nitric oxide synthase (iNOS)-derived NO in hypothalamic activation and in AVP release during severe sepsis induced by cecal ligation and puncture (CLP). Male Wistar rats received i.p. injections of aminoguanidine, an iNOS inhibitor, or saline 30 min before CLP or sham surgeries (controls). CLP led to increased plasma nitrate levels, protein leakage and hypotension and caused mortality of 80% by 24 h. Expression of c-fos in paraventricular (PVN), supraoptic (SON) and organum vasculosum of lamina terminalis (OVLT) nuclei, as well as plasma AVP concentration were increased at 6 h but reduced to basal levels 24 h after CLP. Aminoguanidine pre-treatment prevented the increase in plasma nitrate levels and hypotension in the first 6 h. It also reduced AVP secretion and hypothalamic c-fos expression. After 24 h, the pre-treatment reduced plasma nitrate levels, protein leakage and caused a partial recovery of c-fos expression in SON and OVLT but did not affect AVP release. Furthermore, mortality was reduced to 43%. We conclude that during the early phase of severe sepsis hypotension caused by the iNOS-derived NO is partially responsible for the hypothalamic activation and AVP release. In the late phase, however, the iNOS-derived NO prevents brain activation blunting AVP secretion contributing to hypotension, irreversible shock and animal death.

Participation of the inducible nitric oxide synthase on atrial natriuretic peptide plasma concentration during endotoxemic shock.

Atrial natriuretic peptide (ANP) is a hormone secreted in response to atrial or ventricular volume expansion and pressure overload, respectively. However, it has been found in studies with animals and patients an increase in ANP plasma concentration, during advanced septic shock, despite the fall in mean arterial pressure (MAP). Several studies support the hypothesis that NO may be involved in the regulation of ANP release. Since NO may have an effect on ANP release, we hypothesized that NO pathway may participate in the control of the ANP release induced by the endotoxemic shock. Thus, the purpose of the present study was to assess the effect of the intravenous (i.v.) and intracereboventricular (i.c.v.) administration of aminoguanidine, an iNOS blocker, on plasma ANP levels and MAP during experimental endotoxemic shock. Experiments were performed on adult male Wistar rats weighing 180-240 g. Rats were injected i.v. by bolus injection with 1.5 mg/kg of Lipopolysaccharide (LPS) or saline (0.5 mL) and were decapitated 2, 4 and 6 h after LPS injection for ANP determination by radioimmunoassay. In a separate set of experiments, rats received intravenous (i.v.) (100 mg/kg) or intracerebroventricular (i.c.v.) (250 microg in a final volume of 2 microL) injection of aminoguanidine (AG). Thirty minutes after the i.c.v. or i.v. injections, animals received LPS and were decapitated 2, 4 and 6 h later to determine plasma ANP concentration. In the two set of experiments MAP and heart rate (HR) were measured each 15 min for a period of 6 h using a polygraph. When animals were injected with LPS, a reduction (p<0.01) in MPA and an increase in HR occurred. A significant increase in plasma ANP concentration occurred, coinciding with the period of drop in blood pressure. We found a significant increase in plasma ANP concentration after AG plus LPS injection, when compared to the rats treated with LPS plus saline. Further, the administration of AG plus LPS attenuated the decrease in the MAP after LPS and attenuated the increase in the HR when compared to the rats treated with LPS plus saline. Our study suggests that inducible NOS pathway may activate an inhibitory control mechanism that attenuates ANP secretion, which is not regulated by the changes in blood pressure.

Trends in scientific editing and good research practices: what do researchers-nurses know? / Tendencias en la edición científica y las buenas prácticas de investigación: ¿qué saben los investigadores-enfermeros? / Tendências em editoração científica e boas práticas em pesquisa: o que conhecem os pesquisadores-enfermeiros?

Abstract Objective: To verify researchers-nurses' knowledge about trends in scientific publishing and good research practices. Method: A descriptive study carried out through an online survey with 197 nurses holding master's and/or doctoral degrees from all Brazilian regions. To raise knowledge, a validated, self-administered and anonymous questionnaire with 18 questions on the subject was used. Descriptive and inferential analyzes were performed on researchers' scores (Mann-Whitney test). Results: Among the specific questions, the mean of correct answers was 7.1: 6.4 for master's and 7.4 for doctoral degree holders. There was a significant difference in the mean of correct answers between masters and doctors (p = 0.025), and between productivity scholarship holders and non-scholarship holders (p = 0.021), according to mean difference tests. Questions about predatory editorial practices were those in which researchers had the worst knowledge. Conclusion: We identified that, regardless of the education level (master's or doctoral degree), nurses have little knowledge about the topics studied, which can compromise the quality of production and the scientific vehicles used to disseminate this knowledge.

RESUMEN Objetivo: Verificar el conocimiento de investigadores-enfermeros sobre las tendencias en la publicación científica y las buenas prácticas de investigación. Método: Estudio descriptivo, realizado a través de una encuesta en línea con 197 enfermeros con maestría y/o doctorado de todas las regiones brasileñas. Para aumentar el conocimiento se utilizó un cuestionario validado, autoadministrado y anónimo con 18 preguntas sobre el tema. Sobre la puntuación de los investigadores, se realizaron análisis descriptivos e inferenciales (prueba de Mann-Whitney). Resultados: Entre las preguntas específicas, la media de aciertos fue de 7,1, siendo 6,4 para los másteres y 7,4 para los médicos. Hubo diferencia significativa en la media de aciertos entre maestros y doctores (p = 0,025), y entre becarios de productividad y no académicos (p = 0,021), según pruebas de diferencia de medias. Las preguntas sobre prácticas editoriales depredadoras eran aquellas en las que los investigadores tenían el peor conocimiento. Conclusión: Identificamos que, independientemente del nivel de formación (maestría o doctorado), los enfermeros tienen poco conocimiento sobre los temas estudiados, lo que puede comprometer la calidad de la producción y los vehículos científicos utilizados para difundir este conocimiento.

RESUMO Objetivo: Verificar o conhecimento de pesquisadores-enfermeiros sobre tendências em editoração científica e boas práticas em pesquisa. Método: Estudo descritivo, realizado por inquéritoonlinecom 197 enfermeiros com título de mestre e/ou doutor de todas as regiões brasileiras. Para levantar o conhecimento, utilizou-se um questionário validado, autoaplicável e anônimo com 18 questões sobre o assunto. Sobre o escore dos pesquisadores, realizaram-se análises descritivas e inferenciais (Teste de Mann-Whitney). Resultados: Entre as questões específicas, a média de acertos foi de 7,1, sendo 6,4 para mestres e 7,4 para doutores. Houve diferença significativa na média de acertos entre mestres e doutores (p = 0,025), e entre bolsistas e não bolsistas de produtividade (p = 0,021), segundo testes de diferença de médias. As questões sobre práticas editoriais predatórias foram aquelas em que os pesquisadores apresentaram pior conhecimento. Conclusão: Identificamos que, independente do grau de formação (mestrado ou doutorado), os enfermeiros têm baixo conhecimento sobre os temas estudados, o que pode comprometer a qualidade da produção e dos veículos científicos utilizados para disseminação desse conhecimento.