Resveratrol and fish oil reduce catecholamine-induced mortality in obese rats: role of oxidative stress in the myocardium and aorta.

The exact mechanisms of the relationship between obesity and cardiovascular events are not yet fully understood; however, oxidative stress may be involved. Thus, the aim of the present study was to evaluate the effects of resveratrol and fish oil on catecholamine-induced mortality in obese rats. To begin with, rats were divided into five groups: (1) lean, (2) obese, (3) obese supplemented with resveratrol, (4) obese supplemented with fish oil and (5) obese supplemented with resveratrol and fish oil (n 18 rats per group), for 2 months. After supplementation, the groups were subdivided as with (n 10) and without (n 8) cardiovascular catecholaminergic stress after isoproterenol (60 mg/kg) injection. At 24 h later, the survival rate was analysed. The obese group showed lower survival rates (10 %) when compared with the lean group (70 %). On the other hand, resveratrol (50 %) and fish oil (40 %) increased the survival rate of obese rats (χ(2) test, P= 0·019). Biochemical analyses of the myocardium and aorta revealed that obese rats had higher levels of superoxide and oxidative damage to lipids and protein. This was associated with reduced superoxide dismutase and glutathione peroxidase activity in both the myocardium and aorta. The supplementation increased antioxidant enzyme activities and reduced oxidative damage. We also evaluated the nuclear factor-erythroid 2 p45-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 antioxidant pathway. Nrf2 protein levels that were reduced in obese rats were increased by the antioxidant treatment. Taken together, these results showed that resveratrol and fish oil reduce catecholamine-induced mortality in obese rats, partly through the reduction of oxidative stress.

Corrigendum to "Cross-sectional analysis of students and school workers reveals a high number of asymptomatic SARS-CoV-2 infections during school reopening in Brazilian cities" [Heliyon 8 (11) (November 2022) Article e11368].

[This corrects the article DOI: 10.1016/j.heliyon.2022.e11368.].

Cross-sectional analysis of students and school workers reveals a high number of asymptomatic SARS-CoV-2 infections during school reopening in Brazilian cities.

Brazil experienced one of the most prolonged periods of school closures, and reopening could have exposed students to high rates of SARS-CoV-2 infection. However, the infection status of students and school workers at the time of the reopening of schools located in Brazilian cities is unknown. Here we evaluated viral carriage by RT-PCR and seroprevalence of anti-SARS-CoV-2 antibodies (IgM and IgG) by immunochromatography in 2259 individuals (1139 students and 1120 school workers) from 28 schools in 28 Brazilian cities. We collected the samples within 30 days after public schools reopened and before the start of vaccination campaigns. Most students (n = 421) and school workers (n = 446) had active (qRT-PCR + IgM- IgG- or qRT-PCR + IgM + IgG-/+) SARS-CoV-2 infection. Regression analysis indicated a strong association between the infection status of students and school workers. Furthermore, while 45% (n = 515) of the students and 37% (n = 415) of the school workers were neither antigen nor antibody positive in laboratory tests, 16% of the participants (169 students and 193 school workers) were oligosymptomatic, including those reinfected. These individuals presented mild symptoms such as headache, sore throat, and cough. Notably, most of the individuals were asymptomatic (83.9%). These results indicate that many SARS-CoV-2 infections in Brazilian cities during school reopening were asymptomatic. Thus, our study highlights the need to promote a coordinated public health effort to guarantee a safe educational environment while avoiding exacerbating pre-existent social inequalities in Brazil, reducing social, mental, and economic losses for students, school workers, and their families.

Short-term inhibition of SREBP-1c expression reverses diet-induced non-alcoholic fatty liver disease in mice.

OBJECTIVE: The present study investigates the level of Sterol-regulatory element-binding proteins (SREBP-1c) and related proteins in obese mice (DIO) treated with SREBP-1c antisense oligonucleotide (ASO) to observe a reversal of steatosis. MATERIALS AND METHODS: Swiss mice were fed on chow containing 61 kJ% saturated fat for 8 weeks to develop obesity. After this period, one group of animals was used to assess the molecular effects of SREBP-1c antisense oligonucleotide treatment by immunoblot analysis in a dose-response curve (0; 1.0; 2.0; 3.0; 4.0 nmol/day). After the dose (3.0 nmol/day) was determined, another group was treated for 14 days. After a period of 24 h following the last injection mice were killed and plasma and hepatic tissue were obtained to evaluate plasma triglycerides and total liver fat. Western blot was performed to evaluate SREBP-1c, FAS, SCD-1, PPARγ and CPT1 expression and AMPK[Thr172] and ACC[Ser79] phosphorylation. Livers were stained using the hematoxylin and eosin method for histological analysis. RESULTS: Body weight, epididymal fat and glucose levels were not affected by one daily dose of ASO. However, total plasma triglycerides and total liver fat were significantly reduced. Also, this treatment inhibited SREBP-1c and reduced protein levels of a series of proteins involved in lipogenesis, including ACC, FAS and SCD-1. Moreover, mice treated with ASO presented a significant reduction in macroscopic and microscopic features of hepatic steatosis. CONCLUSION: Our results demonstrate that the inhibition of SREBP-1c decreased the expression of lipogenic enzymes, reducing the accumulation of triglycerides and, finally, reversing hepatic steatosis in mice.

Individuals with isolated congenital GH deficiency due to a GHRH receptor gene mutation appear to cope better with SARS-CoV-2 infection than controls.

PURPOSE: Several interactions exist between the GH/IGF axis and the immune system, including effects on innate immunity and humoral and cellular response. Acquired GH deficiency (GHD) has been recently proposed as a risk factor for severity of COVID-19 infections. However, acquired GHD is often associated to other factors, including pituitary tumors, surgery, radiotherapy, and additional pituitary hormones deficits and their replacements, which, together, may hinder an accurate analysis of the relationship between GHD and COVID-19. Therefore, we decided to assess the seroprevalence of SARS-CoV-2 antibodies and the frequency of symptomatic cases of COVID-19 in adults subjects with untreated isolated GHD (IGHD) due to a homozygous null mutation in the GHRH receptor gene. METHODS: A cross-sectional study was carried out in 27 adult IGHD subjects and 27 age- and gender-matched local controls. Interview, physical examination, bio-impedance, hematological and SARS-CoV-2 IgM and IgG antibodies were analyzed. RESULTS: There was no difference in the prevalence of positivity of anti-SARS-CoV-2 IgM and IgG antibodies between the two groups. Conversely, no IGHD individual had a previous clinical diagnosis of COVID-19 infection, while 6 control subjects did (p = 0.023). CONCLUSION: The production of anti-SARS-CoV-2 antibodies was similar between IGHD subjects due to a GHRH receptor gene mutation and controls, but the evolution to symptomatic stages of the infection and the frequency of confirmed cases was lower in IGHD subjects than in GH sufficient individuals.

Estimated SARS-CoV-2 Infection and Seroprevalence in Firefighters from a Northeastern Brazilian State: A Cross-Sectional Study.

The new coronavirus has been affecting health worldwide and essential service workers are continually exposed to this infectious agent, increasing the chance of infection and the development of the disease. Thus, this study aimed to estimate the frequency of infection and seroprevalence for SARS-CoV-2 in military firefighters in a city in Northeastern Brazil in January 2021. An observational cross-sectional study was carried out with 123 firefighters who answered a brief questionnaire to collect socio-epidemiological data and underwent RT-PCR and immunofluorescence test (IgM and IgG). The results found reveal a positive seroprevalence, with a high rate of infection in this class of workers, since they are essential service professionals who are exposed to risk due to their working hours, in addition to sharing some spaces and work materials. Besides, there were significant associations between positivity for IgG and IgM, as well as for positive RT-PCR prior to the study and the presence of IgG, with odd ratios of 3.04 and 4.9, respectively. These findings reinforce the need for immunization in this category, whose line of service hinders the adoption of distancing measures, since in many situations physical contact is inevitable.

Acute exercise induce endothelial nitric oxide synthase phosphorylation via Akt and AMP-activated protein kinase in aorta of rats: Role of reactive oxygen species.

BACKGROUND: Acute exercise increases reactive oxygen species (ROS) levels, including hydrogen peroxide (H2O2). H2O2 promotes endothelial nitric oxide synthase (eNOS) activation and phosphorylation in endothelial cells. With this in mind, the present study was designed to evaluate ex vivo eNOS phosphorylation in rat aortas incubated with H2O2 and to test this hypothesis in vivo in the aortas of rats submitted to acute exercise. METHODS: For ex vivo studies, six groups of aortic tissue were formed: control, H2O2, N-acetylcysteine (NAC), LY294002, compound C, and LY294002 plus compound C. While incubation with H2O2 increased Akt, AMPK and eNOS phosphorylation, pre-incubation with NAC strongly reduced the phosphorylation of these enzymes. For in vivo studies, male Wistar rats were divided into four groups: control, cont+NAC, exercise, and exer+NAC. After a 3h swimming session, animals were decapitated and aortas were excised for biochemical and immunoblotting analysis. RESULTS: Acute exercise increased superoxide levels and dichlorofluorescein (DCF) concentrations, and this increase was related to phosphorylation of Akt, AMPK and eNOS. On the other hand, use of NAC reduced superoxide levels and DCF concentration. Reduced superoxide levels and DCF in the exer+NAC group were associated with decreased Akt, AMPK and eNOS phosphorylation. These results appear to be connected with vascular function because VASP phosphorylation increased in acute exercise and decreased in exer+NAC. CONCLUSION: Our results indicate that ROS induced by acute exercise play the important role of activating eNOS, a process apparently mediated by Akt and AMPK.

Oxidative damage, inflammation, and Toll-like receptor 4 pathway are increased in preeclamptic patients: a case-control study.

PROBLEM: There was no direct correlation between plasma and placental oxidative damage parameters and inflammation and evidence of TLR4 pathway activation in the placenta in preeclamptic (PE) patients. METHOD OF STUDY: 33 PE patients and 33 normotensive pregnant women were included. The maternal section of the placenta and blood were collected to the determination of oxidative damage markers (thiobarbituric acid reactive species and protein carbonyls), inflammatory response (interleukin-6 and myeloperoxidase activity), and activation of the TLR-4-NF-kB pathway. RESULTS: An increase of IL-6 levels in both plasma and placenta was observed, but myeloperoxidase activity was not significantly different comparing the groups. Oxidative damage parameters were increased in plasma and placenta in PE patients. A significant increase of the protein levels of TLR-4 and NF-kB was observed in the placenta. CONCLUSION: The TLR4-NF-kB pathway is upregulated in PE, probably generating local and systemic inflammatory response that is followed by local and systemic oxidative damage.

RETRACTED: Reversion of hepatic steatosis by exercise training in obese mice: the role of sterol regulatory element-binding protein-1c.

AIM: The dysregulation of regulatory element-binding protein-1c (SREBP-1c) is associated with hepatic steatosis. However, effects of exercise on SREBP-1c protein level in liver have not been investigated. Thus, in this study we investigated if reversion of the hepatic steatosis-induced by exercise training is related with levels of SREBP-1c. MAIN METHODS: Mice were divided into two groups: control lean mice (CT), fed on standard rodent chow, and obese mice (HF), fed on a high-fat diet for 2months. After this period obese mice were divided in two groups: obese mice and obese mice submitted to exercise (HF+EXE). The HF+EXE group performed a running program of 50min per day, 5days per week, for 8weeks. Forty-eight hours after the last exercise session, biochemical, immunoblotting, histology and immunohistochemistry analyses were performed. KEY FINDINGS: Livers of HF mice showed increased SREBP-1c, FAS (Fatty Acid Synthase), SCD1 (Stearoyl-CoA Desaturase1) and CPT1 (Carnitine Palmitoyl Transferase1) protein levels (3.4, 5.0, 2.6 and 2.9 times, respectively), though ACC (Acetyl-CoA Carboxilase) phosphorylation dropped 4.2 times. In livers of HF+EXE, levels of SREBP-1c, FAS, SCDI and CPTI decreased 2.1, 1.9, 1.8, and 2.7 times, respectively), while ACC phosphorylation increased 3.0 times. Lower SREBP-1c protein levels after exercise were confirmed also by immunohistochemistry. Total liver lipids content was higher in HF (2.2 times) when compared to CT, and exercise training reduced it significantly (1.7 times). SIGNIFICANCE: Our study allows concluding that the reduction in SREBP-1c protein levels is associated with steatosis reversion induced by exercise training.