1.
Insulin resistance drives hepatic de novo lipogenesis in nonalcoholic fatty liver disease.
Smith, GI, Shankaran, M, Yoshino, M, Schweitzer, GG, Chondronikola, M, Beals, JW, Okunade, AL, Patterson, BW, Nyangau, E, Field, T, et al
The Journal of clinical investigation. 2020;130(3):1453-1460
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Non-alcoholic fatty liver disease (NAFLD) is a common complication of obesity and is associated with multiorgan insulin resistance, dyslipidaemia and an increased risk of diabetes and coronary heart disease. The aims of this study were to (a) determine hepatic de novo lipogenesis (DNL) [the liver’s biochemical process of synthesising fatty acids] in 3 distinct cohorts, (b) determine the relationships among hepatic DNL and intrahepatic [within the liver] triglyceride (IHTG) content, and (c) determine the effect of moderate (10%) weight loss. This study is a cross-sectional study which included a total of 67 men and women (mean age: 39 ± 1 years; 14 men and 53 women). Results highlight the importance of DNL in the pathogenesis of hepatic steatosis [build up of fats in the liver] and suggest that increases in daily 24-hour plasma glucose and insulin concentrations are major drivers of increased DNL in individuals with obesity and NAFLD. Additionally, moderate (10%) weight loss caused a marked decrease in both hepatic DNL and IHTG content. Authors conclude that increases in circulating glucose and insulin promote hepatic DNL in individuals with NAFLD. Whereas an improvement in insulin sensitivity and a decrease in hepatic DNL, are potentially important contributors to the decline in IHTG content associated with moderate weight loss.
Abstract
BACKGROUNDAn increase in intrahepatic triglyceride (IHTG) is the hallmark feature of nonalcoholic fatty liver disease (NAFLD) and is decreased by weight loss. Hepatic de novo lipogenesis (DNL) contributes to steatosis in individuals with NAFLD. The physiological factors that stimulate hepatic DNL and the effect of weight loss on hepatic DNL are not clear.METHODSHepatic DNL, 24-hour integrated plasma insulin and glucose concentrations, and both liver and whole-body insulin sensitivity were determined in individuals who were lean (n = 14), obese with normal IHTG content (n = 26), or obese with NAFLD (n = 27). Hepatic DNL was assessed using the deuterated water method corrected for the potential confounding contribution of adipose tissue DNL. Liver and whole-body insulin sensitivity was assessed using the hyperinsulinemic-euglycemic clamp procedure in conjunction with glucose tracer infusion. Six subjects in the obese-NAFLD group were also evaluated before and after a diet-induced weight loss of 10%.RESULTSThe contribution of hepatic DNL to IHTG-palmitate was 11%, 19%, and 38% in the lean, obese, and obese-NAFLD groups, respectively. Hepatic DNL was inversely correlated with hepatic and whole-body insulin sensitivity, but directly correlated with 24-hour plasma glucose and insulin concentrations. Weight loss decreased IHTG content, in conjunction with a decrease in hepatic DNL and 24-hour plasma glucose and insulin concentrations.CONCLUSIONSThese data suggest hepatic DNL is an important regulator of IHTG content and that increases in circulating glucose and insulin stimulate hepatic DNL in individuals with NAFLD. Weight loss decreased IHTG content, at least in part, by decreasing hepatic DNL.TRIAL REGISTRATIONClinicalTrials.gov NCT02706262.FUNDINGThis study was supported by NIH grants DK56341 (Nutrition Obesity Research Center), DK20579 (Diabetes Research Center), DK52574 (Digestive Disease Research Center), and RR024992 (Clinical and Translational Science Award), and by grants from the Academy of Nutrition and Dietetics Foundation, the College of Natural Resources of UCB, and the Pershing Square Foundation.
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Daily Intake of Fermented Milk Containing Lactobacillus casei Shirota (Lcs) Modulates Systemic and Upper Airways Immune/Inflammatory Responses in Marathon Runners.
Vaisberg, M, Paixão, V, Almeida, EB, Santos, JMB, Foster, R, Rossi, M, Pithon-Curi, TC, Gorjão, R, Momesso, CM, Andrade, MS, et al
Nutrients. 2019;11(7)
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Athletes undergoing high-intensity efforts show increased incidence of upper respiratory tract infections (URTI), both in the context of competitions and during strenuous training. The aim of this study was to evaluate the influence of the daily intake of fermented milk (containing Lactobacillus casei Shirota) on the systemic and upper airway immune/inflammatory responses before and after a race in marathon runners who previously reported upper respiratory symptoms (URS) after an exhaustive physical exercise session. The study is a double-blind randomised clinical study which recruited 42 male amateur marathon runners with an average age of 39 years. The participants were randomly separated into two groups: Lactobacillus casei Shirota group (n=20) or the placebo group (n=22). Results indicate that daily ingestion of fermented milk (containing Lactobacillus casei Shirota) was able to control both immunological and inflammatory responses in the blood and also in the upper airways mucosal of amateurs´ runners after a marathon. Authors conclude that Lactobacillus casei Shirota is able to modulate the systemic and airways immune responses post-marathon, presenting protective effects.
Abstract
BACKGROUND Although Lactobacillus casei Shirota (LcS) can benefit the immune status, the effects of LcS in the immune/inflammatory responses of marathon runners has never been evaluated. Therefore, here we evaluated the effect of daily ingestion of fermented milk containing or not LcS in the systemic and upper airway immune/inflammatory responses before and after a marathon. METHODS Forty-two male marathon runners ingested a fermented milk containing 40 billion of LcS/day (LcS group, n = 20) or placebo (unfermented milk, n = 22) during 30 days pre-marathon. Immune/inflammatory parameters in nasal mucosa and serum, as well as concentrations of secretory IgA (SIgA) and antimicrobial peptides in saliva, were evaluated before and after fermented milk ingestion, immediately, 72 h, and 14 d post-marathon. RESULTS Higher proinflammatory cytokine levels in serum and nasal mucosa, and also lower salivary levels of SIgA and antimicrobial peptides, were found immediately post-marathon in the placebo group compared to other time points and to LcS group. In opposite, higher anti-inflammatory levels and reduced neutrophil infiltration on nasal mucosa were found in the LcS group compared to other time points and to the placebo group. CONCLUSION For the first time, it is shown that LcS is able to modulate the systemic and airways immune responses post-marathon.
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Glycemic load effect on fasting and post-prandial serum glucose, insulin, IGF-1 and IGFBP-3 in a randomized, controlled feeding study.
Runchey, SS, Pollak, MN, Valsta, LM, Coronado, GD, Schwarz, Y, Breymeyer, KL, Wang, C, Wang, CY, Lampe, JW, Neuhouser, ML
European journal of clinical nutrition. 2012;66(10):1146-52
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Dietary intervention studies have shown detrimental metabolic effects of high-glycaemic load diets. The glycaemic index (GI) is the numerical classification of a particular food’s blood glucose-raising effect. The aim of this study was to evaluate the effect of a high-glycaemic load diet on circulating levels of insulin-like growth factor-1 (IGF-1) [hormone] and insulin-like growth factor-binding protein 3 (IGFBP-3) [protein] compared to a low-glycaemic load diet. The study is a randomised controlled crossover study which enrolled 84 normal weight and overweight-obese healthy individuals. The study included two 28-day weight-maintaining high- and low-glycaemic load diets. Results indicate that consumption of a low-glycaemic load diet resulted in lower post-prandial [after a meal] insulin and glucose responses and modestly lower fasting IGF-1 and IGF-1/IGFBP-3 concentrations. However, there were no observable effects of glycaemic load on insulin resistance or glucose-adjusted post-prandial insulin responses in these healthy participants. Authors conclude that further intervention studies are required in order to weigh the impact of dietary glycaemic load on risk for chronic disease.
Abstract
BACKGROUND/OBJECTIVES The effect of a low glycemic load (GL) diet on insulin-like growth factor-1 (IGF-1) concentration is still unknown but may contribute to lower chronic disease risk. We aimed to assess the impact of GL on concentrations of IGF-1 and IGF-binding protein-3 (IGFBP-3). SUBJECTS/METHODS We conducted a randomized, controlled crossover feeding trial in 84 overweight obese and normal weight healthy individuals using two 28-day weight-maintaining high- and low-GL diets. Measures were fasting and post-prandial concentrations of insulin, glucose, IGF-1 and IGFBP-3. In all 80 participants completed the study and 20 participants completed post-prandial testing by consuming a test breakfast at the end of each feeding period. We used paired t-tests for diet component and linear mixed models for biomarker analyses. RESULTS The 28-day low-GL diet led to 4% lower fasting concentrations of IGF-1 (10.6 ng/ml, P=0.04) and a 4% lower ratio of IGF-1/IGFBP-3 (0.24, P=0.01) compared with the high-GL diet. The low-GL test breakfast led to 43% and 27% lower mean post-prandial glucose and insulin responses, respectively; mean incremental areas under the curve for glucose and insulin, respectively, were 64.3±21.8 (mmol/l/240 min; P<0.01) and 2253±539 (μU/ml/240 min; P<0.01) lower following the low- compared with the high-GL test meal. There was no effect of GL on mean homeostasis model assessment for insulin resistance or on mean integrated post-prandial concentrations of glucose-adjusted insulin, IGF-1 or IGFBP-3. We did not observe modification of the dietary effect by adiposity. CONCLUSIONS Low-GL diets resulted in 43% and 27% lower post-prandial responses of glucose and insulin, respectively, and modestly lower fasting IGF-1 concentrations. Further intervention studies are needed to weigh the impact of dietary GL on risk for chronic disease.