Dirce Ribeiro de Oliveira

Infection with Toxoplasma gondii Increases Atherosclerotic Lesion in ApoE-Deficient Mice

ABSTRACT Toxoplasma gondii is an intracellular protozoan that elicits a potent inflammatory response during the acute phase of infection. Herein, we evaluate whether T. gondii infection alters the natural course of aortic lesions. ApoE knockout mice were infected with T. gondii, and at 5 weeks of infection, serum, feces, and liver cholesterol; aortic lesion size, cellularity, and inflammatory cytokines; and levels of serum nitrite and gamma interferon (IFN-γ) were analyzed. Our results showed that serum cholesterol and atherogenic lipoproteins were reduced after T. gondii infection. The reduction of serum levels of total cholesterol and atherogenic lipoproteins was associated with increases in the aortic lesion area, numbers of inflammatory cells, and expression of monocyte chemoattractant protein 1 and inducible nitric oxide synthase mRNA in the site of lesions as well as elevated concentrations of IFN-γ and nitrite in sera of T. gondii-infected animals. These results suggest that infection with T. gondii accelerates atherosclerotic development by stimulating the proinflammatory response and oxidative stress, thereby increasing the area of aortic lesion.

Predictive ability of anthropometric and body composition indicators in the identification of insulin resistance

OBJECTIVE To assess the ability of anthropometric and body composition indicators in identifying insulin resistance (IR), determining cut-off points for those showing the best efficacy. METHOD 138 men were evaluated. Waist perimeter (WP), sagittal abdominal diameter (SAD), conicity index, body mass index (BMI), body fat percent, sagittal index, and the waist-to-height, waist-to-hip and waist-to-thigh ratios were determined. IR was assessed by the HOMA-IR index. Statistical analysis consisted of Spearman correlation coefficient and ROC (receiver operating characteristic) curves, calculating the area under the curve (AUC). RESULTS SAD (r=0.482, AUC=0.746) and WP (r=0.464, AUC=0.739) showed stronger correlations with the HOMA-IR and greater ability to identify IR (p<0.001), being 89.3 cm and 20.0 cm the best cut-offs, respectively. CONCLUSION The anthropometric indicators of central obesity, WP and SAD, have shown greater ability to identify IR in men. We encourage studies in women and elderly people in search of the best cut-off points for the entire population.

Habilidade de indicadores antropométricos e de composição corporal em identificar a resistência à insulina

OBJECTIVE To assess the ability of anthropometric and body composition indicators in identifying insulin resistance (IR), determining cut-off points for those showing the best efficacy. METHOD 138 men were evaluated. Waist perimeter (WP), sagittal abdominal diameter (SAD), conicity index, body mass index (BMI), body fat percent, sagittal index, and the waist-to-height, waist-to-hip and waist-to-thigh ratios were determined. IR was assessed by the HOMA-IR index. Statistical analysis consisted of Spearman correlation coefficient and ROC (receiver operating characteristic) curves, calculating the area under the curve (AUC). RESULTS SAD (r=0.482, AUC=0.746) and WP (r=0.464, AUC=0.739) showed stronger correlations with the HOMA-IR and greater ability to identify IR (p<0.001), being 89.3 cm and 20.0 cm the best cut-offs, respectively. CONCLUSION The anthropometric indicators of central obesity, WP and SAD, have shown greater ability to identify IR in men. We encourage studies in women and elderly people in search of the best cut-off points for the entire population.

Diferentes aferições do diâmetro abdominal sagital e do perímetro da cintura na predição do HOMA-IR

BACKGROUND The correlation between the increase in visceral fat and insulin resistance makes the sagittal abdominal diameter and the waist perimeter as potential tools for the prediction of insulin resistance. OBJECTIVE To assess the reproducibility of different measurements of the sagittal abdominal diameter and the waist perimeter and analyze the discriminating power of the measurements when predicting insulin resistance. METHODS A total of 190 adult males were studied. The sagittal abdominal diameter (smallest girth, larger abdominal diameter, umbilical level and midpoint between the iliac crests) and the waist perimeter (umbilical level, smallest girth, immediately above the iliac crest and midpoint between the iliac crest and the last rib) were measured at four different sites. Insulin resistance was assessed by the homeostasis model of assessment-insulin resistance (HOMA-IR) index. RESULTS All measurements presented an intraclass correlation of 0.986-0.999. The sagittal abdominal diameter measured at the smallest girth (r=0.482 and AUC=0.739+/-0.049) and the waist perimeter measured at the midpoint between the last rib and the iliac crest (r=0.464 and AUC=0.746+/-0.05) presented the highest correlations with the HOMA-IR and the best discriminating power for HOMA-IR according to the ROC analysis (p<0.001). CONCLUSION The sagittal abdominal diameter and waist perimeter showed to be highly reproducible and the sagittal abdominal diameter (smallest girth) and waist perimeter (midpoint between the iliac crest and the last rib) presented the best performance when predicting HOMA-IR. Further studies in other groups of the Brazilian population must be carried out to allow the use of these indicators of insulin resistance in the population as a whole, following standardized procedures.FUNDAMENTO: A correlacao entre aumento de gordura visceral e de resistencia a insulina coloca o diâmetro abdominal sagital e o perimetro da cintura como instrumentos potenciais para a predicao de resistencia a insulina. OBJETIVO: Avaliar a reprodutibilidade de diferentes afericoes do diâmetro abdominal sagital e do perimetro da cintura e analisar o poder discriminante dos mesmos para predizer resistencia a insulina. METODOS: Foram avaliados 190 homens adultos. O diâmetro abdominal sagital (menor cintura, maior diâmetro abdominal, nivel umbilical e ponto medio entre as cristas iliacas) e o perimetro da cintura (nivel umbilical, menor cintura, imediatamente acima da crista iliaca e ponto medio entre a crista iliaca e a ultima costela) foram aferidos em quatro locais diferentes. A resistencia a insulina foi avaliada pelo indice HOMA-IR. RESULTADOS: Todas as medidas apresentaram correlacao intraclasse de 0,986-0,999. Tanto o diâmetro abdominal sagital aferido na menor cintura (r=0,482 e AUC=0,739±0,049) como o perimetro da cintura aferido no ponto medio entre a ultima costela e a crista iliaca (r=0,464 e AUC=0,746±0,05) apresentaram maiores correlacoes com o HOMA-IR, bem como um melhor poder discriminante para o HOMA-IR segundo a analise ROC (p<0,001). CONCLUSAO: O diâmetro abdominal sagital e o perimetro da cintura mostraram-se altamente reprodutiveis. O diâmetro abdominal sagital (menor cintura) e o perimetro da cintura (ponto medio crista iliaca e ultima costela) apresentaram melhor desempenho em predizer o HOMA-IR. Investigacoes em outros grupos da populacao brasileira devem ser realizadas para viabilizar a utilizacao desses indicadores de resistencia a insulina na populacao como um todo de forma padronizada.

Impact of protein malnutrition on histological parameters of experimentally infected animals with Giardia lamblia

Giardiasis is one of the most common parasitic diseases worldwide, and the disease is an important cause of diarrhoea and malabsorption in children and immunosuppressed individuals. However, there is no evidence that characterises malnutrition as an aggravating factor for this disease. We evaluated changes in villi structures to examine the association between malnutrition and Giardia lamblia infection. We used 32 gerbils, divided into 4 groups: Control (CT) and Control Infected (CTIn), which each received a 20% protein diet, Malnourished (MN) and Malnourished Infected (MNIn), which each received a 5% protein diet. Groups CTIn and MNIn were inoculated with 1×10(6) trophozoites of G. lamblia, while the remaining groups were mock infected. Seven days post-infection, all groups were sacrificed, and the proximal portions of the small intestines were collected for the analysis of villus height, mucus area and extent of Giardia infection. Gerbils fed with a low-protein diet had significantly lower body weights. Malnourished infected animals presented significantly increased production of mucus, suggesting a synergism occurs between malnutrition and Giardiasis, potentially to control the adhesion of Giardia in the mucosa. Villus height was significantly lower in group MNIn compared to CTIn. This work suggests that malnutrition contributes to severity of Giardiasis by decreasing the intestinal absorption capacity via shortening of the villi.

Gelatin intake increases the atheroma formation in apoE knock out mice.

The effect of gelatin ingestion on cholesterol metabolism and on atheroma formation was evaluated in both wild type (n=14) and apoprotein E (apoE) knock out (apoE(-/-)) (n=20) C57BL/6 7-week-old mice. Animals were fed a cholesterol-free isoproteic semi-purified diet containing 20% of casein (control diet) or 10% of casein plus 10% of gelatin (gel diet) for 8 weeks. In wild type mice, dietary gelatin caused a reduction in the serum triacylglycerols levels associated with an increase in the fecal excretion. No difference in blood cholesterol was seen at the sixth week of experiment. At the eighth week of experiment, there was a modest but significant reduction of serum total and high density lipoprotein (HDL) cholesterol in apoE(-/-) mice fed on gel diet compared to the control. Total cholesterol/HDL cholesterol ratio was 2-fold higher in the gel group than that seen in the control group (14.39 and 7.84, respectively). Histological analyzes showed a 2.2-fold increase in the dimension of the atherosclerotic plaques in the proximal aorta in apoE(-/-) mice fed on a gel diet compared to those fed on a control diet. The gel diet also promoted a reduction in the fecal excretion of bile acids. Hepatic cholesterol was similar in both groups. In conclusion, although gelatin reduced total serum cholesterol, this reduction was associated to a decrease of HDL cholesterol and consequent increase of total cholesterol/HDL cholesterol ratio, resulting in an acceleration of atherogenesis.

Indicadores do perfil lipídico plasmático relacionados à resistência à insulina

PURPOSE: To investigate the effectiveness of biochemical indicators from the plasmatic lipid profile to identify the insulin resistance (IR), assessed by the HOMA-IR index (Homeostasis Model Assessment -Insulin Resistance). METHODS: 138 healthy men (20-59 years) were evaluated. The lipid profile biochemical indicators analyzed were the following: triglycerides (TG), total cholesterol (TC), HDL-C, LDL-C, and TC/HDL-C and TG/HDL-C ratios. The percentile 75 was considered as the cut-off point for IR. Statistical analysis consisted of Spearman correlation coefficient, ROC curves and calculation of the areas under the curve (AUC). RESULT: The TG/HDL-C ratio showed the strongest correlation and the greatest AUC (r = 0.334 and AUC = 0.724 ± 0.046, p 0.05). CONCLUSION: The TG/HDL-C ratio showed the greatest ability to identify IR, proved to be an alternative and easy access instrument to assess IR in clinical practice, therefore providing diseases prevention for the adult male population.

Different measurements of the sagittal abdominal diameter and waist perimeter in the prediction of HOMA-IR

BACKGROUND The correlation between the increase in visceral fat and insulin resistance makes the sagittal abdominal diameter and the waist perimeter as potential tools for the prediction of insulin resistance. OBJECTIVE To assess the reproducibility of different measurements of the sagittal abdominal diameter and the waist perimeter and analyze the discriminating power of the measurements when predicting insulin resistance. METHODS A total of 190 adult males were studied. The sagittal abdominal diameter (smallest girth, larger abdominal diameter, umbilical level and midpoint between the iliac crests) and the waist perimeter (umbilical level, smallest girth, immediately above the iliac crest and midpoint between the iliac crest and the last rib) were measured at four different sites. Insulin resistance was assessed by the homeostasis model of assessment-insulin resistance (HOMA-IR) index. RESULTS All measurements presented an intraclass correlation of 0.986-0.999. The sagittal abdominal diameter measured at the smallest girth (r=0.482 and AUC=0.739+/-0.049) and the waist perimeter measured at the midpoint between the last rib and the iliac crest (r=0.464 and AUC=0.746+/-0.05) presented the highest correlations with the HOMA-IR and the best discriminating power for HOMA-IR according to the ROC analysis (p<0.001). CONCLUSION The sagittal abdominal diameter and waist perimeter showed to be highly reproducible and the sagittal abdominal diameter (smallest girth) and waist perimeter (midpoint between the iliac crest and the last rib) presented the best performance when predicting HOMA-IR. Further studies in other groups of the Brazilian population must be carried out to allow the use of these indicators of insulin resistance in the population as a whole, following standardized procedures.FUNDAMENTO: A correlacao entre aumento de gordura visceral e de resistencia a insulina coloca o diâmetro abdominal sagital e o perimetro da cintura como instrumentos potenciais para a predicao de resistencia a insulina. OBJETIVO: Avaliar a reprodutibilidade de diferentes afericoes do diâmetro abdominal sagital e do perimetro da cintura e analisar o poder discriminante dos mesmos para predizer resistencia a insulina. METODOS: Foram avaliados 190 homens adultos. O diâmetro abdominal sagital (menor cintura, maior diâmetro abdominal, nivel umbilical e ponto medio entre as cristas iliacas) e o perimetro da cintura (nivel umbilical, menor cintura, imediatamente acima da crista iliaca e ponto medio entre a crista iliaca e a ultima costela) foram aferidos em quatro locais diferentes. A resistencia a insulina foi avaliada pelo indice HOMA-IR. RESULTADOS: Todas as medidas apresentaram correlacao intraclasse de 0,986-0,999. Tanto o diâmetro abdominal sagital aferido na menor cintura (r=0,482 e AUC=0,739±0,049) como o perimetro da cintura aferido no ponto medio entre a ultima costela e a crista iliaca (r=0,464 e AUC=0,746±0,05) apresentaram maiores correlacoes com o HOMA-IR, bem como um melhor poder discriminante para o HOMA-IR segundo a analise ROC (p<0,001). CONCLUSAO: O diâmetro abdominal sagital e o perimetro da cintura mostraram-se altamente reprodutiveis. O diâmetro abdominal sagital (menor cintura) e o perimetro da cintura (ponto medio crista iliaca e ultima costela) apresentaram melhor desempenho em predizer o HOMA-IR. Investigacoes em outros grupos da populacao brasileira devem ser realizadas para viabilizar a utilizacao desses indicadores de resistencia a insulina na populacao como um todo de forma padronizada.

Obesity-induced diet leads to weight gain, systemic metabolic alterations, adipose tissue inflammation, hepatic steatosis, and oxidative stress in gerbils (Meriones unguiculatus)

Background Nowadays, the number of obese people in the world has reached alarming proportions. During the expansion of adipose tissue, a number of functions such as activation and release of cytokines and hormones may be affected. This leads the body to a pro-inflammatory pattern, which may affect the proper functioning of many tissues. Thus, studying the mechanisms by which obesity induces physiological disorders is necessary, and may be facilitated by the use of animal models, in particular rodents. We sought to characterize the metabolic and adipose tissue changes resulting from a diet rich in fats and simple sugars in gerbils. Methods We divided 14 gerbils into two experimental groups that received a diet rich in simple carbohydrates and fats with 5,86 kcal/g (OB, n = 7) or a standard diet with 4.15 kcal/g (CT; n = 7) for 11 weeks. The animals had free access to water and food. The animal weight and food consumption were measured weekly. Blood, adipose tissue and liver of each animal were collected at the end of experiment. The following parameters were determined: cholesterol (COL), triglycerides (TGL) and glycemia (GLI) in the plasma; cytokines (IL-6, IL-10 and TNF-α) and hormones (adiponectin and leptin) in adipose tissue; activity of superoxide dismutase (SOD) and catalase (CAT), extraction and differentiation of fat and histology in liver. Results The consumption of a diet rich in simple carbohydrates and fats led to increased total body weight and increased relative weights of liver and adipose tissue. In addition, we observed increased fasting glucose levels and circulating triglycerides, along with high TNF-α production in adipose tissue and increased total fat, cholesterol and triglyceride contents in the liver, contributing to higher intensity of hepatic steatosis. On the other hand, the animals of this group showed depletion in the enzyme activity of SOD and CAT in the liver, as well as reduction of IL-10 and adiponectin levels in adipose tissue. Discussion High intake of saturated fat and simple carbohydrates establish the gerbil as an experimental model for the study of metabolic and hepatic abnormalities resulting from obesity.

Effect of giardiasis combined with low-protein diet on intestinal absorption of glucose and electrolytes in gerbils.

Studies have shown that symptomatic infection by Giardia lamblia causes acute or chronic diarrhea, dehydration, abdominal pain and malabsorption, leading to undernutrition and weight loss. The aim of the present study was to evaluate the effects of giardiasis and its combination with a low-protein diet on the intestinal absorption of glucose and electrolytes in gerbils. The intestinal absorption of glucose, sodium and potassium was investigated in male gerbils weighing 46-64 g (n≥5). A Tyrode solution containing twice the glucose, sodium and potassium concentration (pH 7.4) was infused through the intestinal loops for 40 min. Glucose absorption was not significantly affected by diet and infection. However, there was a significant increase in sodium absorption in the Giardia-infected group (57.2±6.1, p<0.05) in comparison to the control, low-protein diet and low-protein diet+Giardia-infected groups (8.9±6.5, 2.8±11.1 and 0.8±7.9, respectively; p<0.05). Moreover, potassium was absorbed in the Giardia-infected group (0.45±0.30), while the other groups exhibited potassium secretion. A low-protein diet and Giardia infection had no influence over glucose absorption. However, Giardia infection increased sodium and potassium uptake, suggesting a compensatory mechanism for maintaining homeostasis after likely hypernatremia and hypokalemia caused by the diarrhea that accompanies giardiasis.