Percorrer por autor "Pereira, Sofia S."
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- Effects of high-intensity infrasound on liver lipid content of ratsPublication . Pereira, Gonçalo Martins; Pereira, Sofia S.; Santos, Madalena; Brito, José; Freitas, Diamantino; Carvalho, António Oliveira de; Águas, Artur; Oliveira, Maria João; Oliveira, PedroPrevious experimental studies show that exposure to noise with high and audible frequencies causes multiple metabolic alterations, such as increased liver glycogen and triglycerides. However, the effect of exposure to sound with lower frequencies, such as high-intensity infrasound (frequency <20 Hz and sound pressure level >90 dB), on the liver lipid content is still unclear. As such, we aimed to study the effect of exposure to high-intensity infrasound of both normal and glucose intolerant rats on the liver lipid content. For this study, 79 wild-type male Wistar rats were randomly divided into two groups: G1, no treatment, and G2, induced glucose intolerance. Each of these two groups was randomly divided in two subgroups: s (animals kept in silence) and i (animals continuously exposed to high-intensity infrasound noise). At three noise-exposure time-points (1, 6 and 12 weeks) the rats were sacrificed, the liver was excised and hepatic lipids extracted. Data analysis was performed using a two-way ANOVA (p = 0.05). No significant effects due to interactions between the several factors exist on the liver lipid content (p=0.077). Moreover, no significant effects due to infrasound exposure (p=0.407) or glucose tolerance status (p=0.938) were observed. Our study shows that continuous exposure to high-intensity infrasound has no influence on the lipid content of the liver of both normal and glucose intolerant animals. This finding reinforces the need for further experimental studies on the physiological effects of infrasound due to its possible hazardous effects on human health.
- High-intensity infrasound effects on glucose metabolism in ratsPublication . Pereira, Gonçalo Martins; Santos, Madalena; Pereira, Sofia S.; Borrecho, Gonçalo; Tortosa, Francisco; Brito, José; Freitas, Diamantino; Carvalho, António Oliveira de; Águas, Artur; Oliveira, Maria João; Oliveira, PedroRecent focus has been given on the effects of high-intensity infrasound (HII) exposure, and whether it induces changes in pancreatic morphology and glucose metabolism is still unknown. As such, we have studied the impact of HII exposure on glucose tolerance, insulin sensitivity, pancreatic islet morphology, muscle GLUT4 and plasma insulin and corticosterone levels. Normal and glucose intolerant wild-type Wistar rats were randomly divided in two groups: one group not exposed to HII and the other continuously exposed to HII. Animals were sacrificed at three timepoints of exposure (1, 6 or 12 weeks). An intraperitoneal glucose tolerance test was performed, blood samples were collected and the pancreas and the quadriceps femoris muscle were excised. Circulating insulin and corticosterone levels were determined and pancreatic and muscular tissue were routinely processed for histochemistry and immunohistochemistry with an anti-GLUT4 antibody. Animals exposed to HII had higher corticosterone levels than animals not exposed. No differences were found on insulin concerning HII exposure or glucose intolerance. Glucose intolerant animals had pancreatic islet fibrosis and no differences were found in GLUT4 ratio concerning HII exposure. In conclusion, we found that continuous exposure to HII increases stress hormone levels without inducing glucose intolerance in rats.
- Impact of prolonged fasting and refeeding on enteroendocrine hormone expression : one more piece of the fasting/refeeding metabolic puzzlePublication . Nunes, Gonçalo; Guimarães, Marta; Oliveira, Sofia B.; Pereira, Sofia S.; Vara-Luiz, Francisco; Mendes, Ivo; Palma, Carolina; Oliveira, Cátia; Fonseca, JorgeIntroduction: Prolonged fasting induces histological and ultrastructural changes of the intestinal mucosa that may reduce absorption in malnourished patients with high risk of refeeding syndrome. Endocrine function of the intestinal mucosa may be affected by starvation with potential implications for nutritional support. Objective: The present study aims to evaluate the expression of gastrointestinal hormones in duodenal enteroendocrine cells (EECs) of patients after a long starvation period and to assess the changes in EEC hormonal expression after enteral refeeding in the same individuals. Methods: This was an observational prospective controlled study. Adult patients submitted to endoscopic gastrostomy (PEG) with an ingestion below 50% of daily needs for at least one month were enrolled. Duodenal biopsies were collected before gastrostomy (T0) and after 3–6 months of PEG feeding (T1). Biopsies underwent immunohistochemical analysis for chromogranin-A (CgA), neurotensin and incretin (GLP-1 and GIP) tissue expression. Normal duodenum biopsies were used as controls. Results: A total of 30 patients (16 men/14 women) aged 67.1 ± 13.5 years were included, and 14 patients completed follow-up at both periods (46.7%). Malnutrition was diagnosed in all patients according to GLIM criteria. T0 tissue expression defined by median stained area for CgA, GLP-1, and GIP were significantly higher in patients compared to controls (CgA: 1.04% vs. 0.41%; GLP-1: 0.17% vs. 0.03%; GIP: 0.19% vs. 0.03%) (p < 0.001) without differences for neurotensin (0.01%) (p = 0.96). T1 hormonal tissue expression was not significantly reduced after 3–6 months of enteral refeeding (p > 0.05). Conclusions: Prolonged fasting induces increased expression of incretins and chromogranin-A in the duodenum that probably reflect an adaptative response to maintain the anabolic insulin effect under nutritional deficiency. Hormonal expression does not normalize after PEG refeeding during a short period.
- Prolonged fasting induces histological and ultrastructural changes in the intestinal mucosa that may reduce absorption and revert after enteral refeedingPublication . Nunes, Gonçalo; Guimarães, Marta; Coelho, Hélder; Carregosa, Ricardo; Oliveira, Cátia; Pereira, Sofia S.; Matos, António Alves de; Fonseca, JorgeBackground: Malnutrition is usual in patients referred for endoscopic gastrostomy (PEG). Refeeding syndrome is rarely observed in PEG-fed patients, which could possibly be associated with reduced absorption induced by prolonged starvation. Objective: In patients submitted to PEG after a significant period of fasting, the present study aims to: 1. evaluate the histological/ultrastructural initial changes in the intestinal mucosa, potentially associated with reduced absorption, and 2. assess if these changes could reverse with enteral refeeding. Methods: The present study is an observational, prospective, controlled study. Adult patients with ingestion below 50% of daily needs for at least one month and/or diagnosis of malnutrition were enrolled. Duodenal biopsies were taken at baseline and after 3–6 months of PEG feeding, which then underwent histological/ultrastructural analysis. Random healthy individuals were used as controls. Results: A total of 30 patients (16 men/14 women) aged 67.1 ± 13.5 years were included. Malnutrition was found in 40% of patients. Approximately 14 patients completed follow-up during both periods (46.7%). At baseline: duodenal mucosal atrophy was evident in three patients (10%); the median villi length (MVL) was 0.4 mm (0.25–0.6 mm), with it being shorter than the controls, which was 0.6 mm (0.4–0.7 mm) (p = 0.006); ultrastructural changes included focal shortening, bending, and disruption of enterocyte microvilli, the presence of citoplasmatic autophagic vacuoles, dilation and vesiculation of the smooth endoplasmic reticulum, and the presence of dilated intercellular spaces with basement membrane detachment. After refeeding, most patients displayed normal histology (92.9%) and increase MVL (p < 0.001), ultrastructural changes disappeared, and enterocytes resumed a normal appearance, although retaining scarce, small, dense bodies in apical regions from the evolution of previous autophagy. Conclusions: Prolonged fasting induces histological and ultrastructural changes in the intestinal mucosa that may reflect impaired absorption in the early post-PEG period. These changes were reverted after refeeding with enteral nutrition.