The ratio of insulin-like growth factor-I/insulin-like growth factor–binding protein-3 in sera of patients with hepatitis C virus–related chronic liver disease as a predictive marker of insulin resistance

Recent studies have elucidated a lower level of serum insulin-like growth factor-I (IGF-I) or a decrease in the IGF-I/IGF-binding protein-3 (IGFBP-3) ratio in patients with type 2 diabetes mellitus or hepatic steatosis. Persistent hepatitis C virus (HCV) infection often evokes metabolic abnormalities including hepatic steatosis and insulin resistance. We hypothesized that the relationship between the ratio of IGF-I/IGFBP-3 and the severity of hepatic steatosis or insulin resistance would be observed in patients with HCV-related chronic liver disease (CLD). On the basis of the classifications proposed by Brunt and colleagues (Am J Gastroenterol 1999; 94: 2467-2474), among the 42 enrolled patients with HCV-related CLD, 23 of them had no hepatic steatosis (grade 0), 14 had grade 1 steatosis, and 5 had grade 2 steatosis. The levels of serum IGF-I in the enrolled patients declined in proportion to the severity of hepatic steatosis, whereas serum IGFBP-3 levels did not affect its severity. Therefore, the ratio of IGF-I/IGFBP-3, which corresponds to the circulating free IGF-I status, was significantly lower in those patients with hepatic steatosis (grades 1 and 2) than in those without hepatic steatosis. Serum IGF-I levels significantly correlated with serum zinc levels (r = 0.370, P = .0266), but IGFBP-3 levels did not. However, the linear regression analysis revealed an inverse correlation between the IGF/IGFBP-3 ratio and the value of homeostasis model for assessment of insulin resistance (r =−0.411, P = .0094). These findings suggest that the decline of the circulating free IGF-I level, which derives from zinc deficiency, may contribute to hepatic steatosis and insulin resistance in patients with HCV-related CLD.     

Total dietary fat and fatty acid content modifies plasma phospholipid fatty acids,desaturase activity indices,and urinary prostaglandin E in women

Compared with diets high in fat, low-fat diets are associated with reduced risk of cardiovascular disease. We hypothesized that a low-fat (LF) (20% fat) and an LF high–omega-3 (n-3) fatty acid diet (LFn3) (23% fat with 3% as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid [DHA]) would enhance n-3 composition of plasma phospholipid fatty acid and reduce urinary prostaglandin E₂ (PGE₂) relative to a high-fat diet (HF) (40% fat) and that these changes would be associated with alterations in δ5 desaturase (D5D) and δ6 desaturase (D6D) activity. Phospholipid fatty acids and urinary PGE₂ were measured, and D5D and D6D activity indices calculated in a crossover trial in 17 postmenopausal women fed each of 3 test diets (HF, LF, and LFn3) for 8-week feeding periods. Desaturase activity indices were calculated as D5D, 20:4n-6/20:3n-6, and D6D, 20:3n-6/18:2n-6. Plasma phospholipid fatty acid, α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid (DPA), DHA, and total n-3 fatty acids increased, whereas linoleic acid and arachidonic acid decreased with consumption of LFn3. The LF resulted in enhanced arachidonic acid and DHA. High fat reduced D6D, whereas both HF and LF increased D5D. Urinary PGE₂ was reduced in response to both the LF and LFn3 diets. Low-fat diets, with or without long-chain n-3 fatty acids, promote positive health effects due in part to favorable alteration of plasma phospholipid fatty acid profiles and modification in desaturase activity indices, suggesting that the type and amount of fat consumed are modifiable risk factors for the prevention of cardiovascular disease.     

Short-term hypocaloric nutrition but not bed rest decrease insulin sensitivity and IGF-I bioavailability in healthy subjects: The importance of glucagon

Hyperinsulinemic, normoglycemic clamps were performed before and after 24 h of either hypocaloric nutrition or bed rest in healthy subjects. Decreased insulin sensitivity and insulin-like growth factor-I (IGF-I) bioavailibility, as measured by the serum IGF-I/insulin-like growth factor binding protein-1 (IGFBP-1) ratio, was found after fasting, whereas no metabolic changes were found after bed rest. Glucagon seems to be a key regulator of IGFBP-1 after brief hypocaloric nutrition. Hypocaloric nutrition and immobilization may add to the catabolic response to surgery and other trauma. Presently, six healthy subjects were studied before and after a 24-h period of hypocaloric nutrition (200 kcal/24 h, fast) or immobilization (bed rest) using the hyperinsulinemic (0.8 mU · kg⁻¹ · min⁻¹), normoglycemic (4.5 mmol/L) clamp, indirect calorimetry, and circulating levels of substrates and hormones. After fast, body weight decreased (P < 0.05), and nitrogen balance was negative (−10 ± 1 g urea nitrogen/24 h). Basal levels of free fatty acids, glucagon, and IGFBP-1 increased (P < 0.05), whereas c-peptide levels and the IGF-I/IGFBP-1 ratio decreased (P < 0.05). However, no change was found in basal levels of IGF-I or substrate oxidation. Furthermore, changes (%) in basal levels of glucagon after fast correlated to IGFBP-1 (r = 1.0, P < 0.05), whereas the suppressibility of IGFBP-1 by insulin was maintained at normal levels. During clamps, glucose infusion rates (GIR) decreased after fast (−43 ± 13%, mean ± SEM, P < 0.001). Although not significant, clamp levels of fat oxidation tended to increase and glucose oxidation tended to decrease. Levels of IGFBP-1 during clamps were higher as compared with the control clamp (P < 0.05). No adverse metabolic changes were seen after bed rest, and no change in GIR during clamps were seen as compared with the control measurement (0 ± 14%). After brief hypocaloric nutrition, insulin sensitivity is reduced, whereas IGF-I bioavailibility is reduced by an increase in levels of IGFBP-1. Glucagon seems to contribute to the increase in IGFBP-1 during these conditions.     

不同出生胎龄的2～7岁小于胎龄儿生长激素释放多肽、胰岛素样生长因子-1、胰岛素水平及其与生长发育的关系

目的探讨生长激素释放多肽(Ghrelin)、胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)、胰岛素在小于胎龄儿(SGA)生长发育中的作用。方法分别检测2～7岁早产SGA、足月SGA血Ghrelin、IGF-1、IGFBP-3、胰岛素、血糖的水平,并与相应的早产AGA、足月AGA进行比较,并做相关性分析。结果 Ghrelin在早产SGA组高于足月SGA(P<0.05),与早产AGA无明显差异,早产AGA高于足月AGA(P<0.05),足月SGA高于足月AGA(P<0.01)。IGF-1和IGFBP-3水平在早产SGA组低于足月SGA(P<0.05),早产AGA组明显低于足月AGA组(P<0.0001)。胰岛素水平在足月SGA组最高。胰岛素抵抗指数(IRI)在各组间比较与胰岛素结果一致。早产SGA组与足月SGA组中Ghrelin与各项指标的相关分析显示:Ghrelin与体重标准差计分(SDS)、IGF-1、IGFBP-3、胰岛素及IRI呈负相关,早产SGA组分别为(r=-0.683,P<0.002;r=-0.749,P<0.001;r=-0.828,P<0.001;r=-0.694,P<0.005;r=-0.822,P<0.001),足月SGA组分别为(r=-0.792,P<0.001;r=-0.707,P<0.002;r=-0.615,P<0.01;r=-0.648,P<0.005;r=-0.679,P<0.005)。结论 Ghrelin参与了早产儿和SGA儿生后的生长发育过程,但与追赶生长程度的关系不大。Ghrelin作为胰岛素的反调节因子,以负反馈的形式调节能量代谢。     

Low dosages of exogenous growth hormone and its effect on growth in an animal model of suboptimal nutrition

In a previous study, weight gain, insulin growth factor-1 (IGF-1) and insulin growth factor binding protein-3 (IGFBP-3) were increased in rats fed suboptimal levels of energy and administered 0.1 mg/100 g of body weight of recombinant human growth hormone (rhGH). Our objective was to determine whether these anabolic effects were still obtained with lower dosages of rhGH in similarly fed rats. Three groups of male, prepubertal Sprague-Dawley rats were administered rhGH and three groups of similar rats were given normal saline solution daily (0.05 mg/100 g of body weight subcutaneously). All rats were fed a balanced 1:1 carbohydrate:fat ratio diet for 4 wk. Restricted rats within each treatment were pair fed 80% and 60% ad libitum. Daily body weight, food intake, and efficiency were recorded. After 4 wk, serum IGF-1 and IGFBP-3, body fat, fat-free mass, and total body water were determined. Total weight gain and serum IGFBP-3 were significantly higher, with a tendency for increased body fat, in rats treated with rhGH and fed at 60% ad libitum. However, within each treatment, energy restriction caused decreased body fat and total body water. These results suggest that lower dosages of rhGH provide anabolic effects during suboptimal energy intake.     

The potential role of insulin-like growth factor 1, insulin-like growth factor binding protein 3 and bone mineral density in patients with chronic hepatitis C virus in Cairo, Egypt

Insulin-like growth factor 1 (IGF-1) levels have been found to correlate with measurements of bone mineral density (BMD) in liver diseases. This study investigated the relationship between IGF-1, insulin-like growth factor binding protein 3 (IGFBP-3) and BMD in patients with chronic hepatitis C virus. This study was conducted for 30 patients with chronic hepatitis C virus infection (16 patients without and 14 patients with cirrhosis) and 11 healthy controls. Serum levels of IGF-1 and IGFBP-3 and BMD of the proximal femur and lumbar spine were measured in all subjects. Osteoporosis of the proximal femur and lumbar spine was found in 42.9% and 21.4%, respectively, of the patients with cirrhosis. Patients with liver cirrhosis and osteoporosis of the proximal femur and lumbar spine had lower IGF-1 (P < 0.001, P = 0.04, P = 0.04 respectively). BMD of the proximal femur was lower in cirrhotic patients compared with controls (P < 0.01). Patients with liver cirrhosis had lower IGFBP-3 than patients without cirrhosis and controls (P < 0.001). Patients with osteoporosis of the proximal femur had lower IGFBP-3 than those without osteoporosis (P < 0.01). IGF-1 and IGFBP-3 levels were lower in patients with liver cirrhosis. IGF-1 and IGFBP-3 may play a role in hepatic osteoporosis.     

非营养性吸吮对早产儿血清IGF-1、IGFBP-3及生长发育的影响

目的:探讨非营养性吸吮对早产儿血清IGF-1、IGFBP-3及生长发育的影响。方法:以2008年9月～2009年8月收治的早产儿60例为研究对象,随机分为非营养性吸吮(NNS)组和对照组,采用ELISA法测定生后第1天开奶前及生后第3天、第7天、第14天血清IGF-1、IGFBP-3水平,同时记录生长发育指标(头围、身长)。结果:①NNS组血清IGF-1、IGFBP-3水平在生后第7、14天高于对照组(P<0.05)。②与对照组相比,NNS组第14天头围、体重增长差异有统计学意义(P<0.01)。③血清IGF-1与头围、体重增长呈正相关(r=0.684,P<0.01;r=0.656,P<0.01),与血清IGFBP-3水平呈正相关(r=0.659,P<0.01)。结论:NNS能提高血清IGF-1、IGFBP-3水平,加快早产儿的生长发育。     

Comparison of a very low-carbohydrate and low-fat diet on fasting lipids, LDL subclasses, insulin resistance, and postprandial lipemic responses in overweight women

OBJECTIVE: Very low-carbohydrate diets are widely used for weight loss yet few controlled studies have determined how these diets impact cardiovascular risk factors compared to more traditional low-fat weight loss diets. The primary purpose of this study was to compare a very low-carbohydrate and a low-fat diet on fasting blood lipids, LDL subclasses, postprandial lipemia, and insulin resistance in overweight and obese women. METHODS: Thirteen normolipidemic, moderately overweight (body fat >30%) women were prescribed two hypocaloric (-500 kcal/day) diets for 4 week periods, a very low-carbohydrate (<10% carbohydrate) and a low-fat (<30% fat) diet. The diets were consumed in a balanced and randomized fashion. Two fasting blood draws were performed on separate days and an oral fat tolerance test was performed at baseline, after the very low-carbohydrate diet, and after the low-fat diet. RESULTS: Compared to corresponding values after the very low-carbohydrate diet, fasting total cholesterol, LDL-C, and HDL-C were significantly (p < or = 0.05) lower, whereas fasting glucose, insulin, and insulin resistance (calculated using the homeostatic model assessment) were significantly higher after the low-fat diet. Both diets significantly decreased postprandial lipemia and resulted in similar nonsignificant changes in the total cholesterol/HDL-C ratio, fasting triacylglycerols, oxidized LDL, and LDL subclass distribution. CONCLUSIONS: Compared to a low-fat weight loss diet, a short-term very low-carbohydrate diet did not lower LDL-C but did prevent the decline in HDL-C and resulted in improved insulin sensitivity in overweight and obese, but otherwise healthy women. Small decreases in body mass improved postprandial lipemia, and therefore cardiovascular risk, independent of diet composition.     

胰岛素样生长因子在诊断儿童生长激素缺乏症中的临床价值

目的 探讨胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)检测在诊断矮小儿童生长激素缺乏症的临床价值。方法 收集65例临床诊断为矮小儿童血清标本,其中生长激素缺乏(GHD)组52例,特发性矮小症(ISS)组13例。收集46名健康儿童血清标本作为对照组。用化学发光法分别检测血清IGF-1和IGFBP-3浓度。结果 与对照组比较,GHD组和ISS组患儿血清IGF-1和IGFBP-3浓度均显著降低,差异均有统计学意义(P<0.05);GHD组血清IGF-1、IGFBP-3浓度分别为(105.53±75.22)ng/mL、(2.52±1.06)μg/mL,ISS组分别为(197.41±87.43)ng/mL、(3.61±1.50)μg/mL,差异有统计学意义(P<0.05)。结论 IGF-1、IGFBP-3可以为临床诊断矮小儿童生长激素缺乏症提供重要参考价值。     

A Low Glycemic Index and Glycemic Load Diet Decreases Insulin-like Growth Factor-1 among Adults with Moderate and Severe Acne: A Short-Duration, 2-Week Randomized Controlled Trial

Background

A high glycemic index (GI) and glycemic load (GL) diet may stimulate acne proliferative pathways by influencing biochemical factors associated with acne. However, few randomized controlled trials have examined this relationship, and this process is not completely understood.

IGF-Ⅰ、IGF-Ⅱ、IGFBP-1与妊娠期高血压疾病的相关性研究

目的研究妊娠期高血压疾病(hypertensive disorder complicating pregnancy,HDCP)与胰岛素样生长因子-Ⅰ(insulin-like growth factor-Ⅰ,IGF-Ⅰ)、胰岛素样生长因子-Ⅱ(insulin-like growth factor-Ⅱ,IGF-Ⅱ)、胰岛素样生长因子结合蛋白-1(insulin-like growth factor binding protein-1,IGFBP-1)的相关性,为HDCP的病因学研究提供理论依据。方法采用酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)检测脐血和羊水中IGF-Ⅰ、IGF-Ⅱ、IGFBP-1水平。正常孕妇16例(对照组),HDCP孕妇48例(研究组),其中妊娠期高血压17例,轻度子痫前期16例,重度子痫前期15例。结果研究组较对照组IGF-Ⅰ、IGF-Ⅱ水平均显著下降(P<0.05)、IGFBP-1水平显著升高(P<0.05);研究组内IGF-Ⅰ和IGF-Ⅱ水平随病情程度加重而降低、IGFBP-1水平随病情程度加重而升高,不同病情程度之间比较差异有统计学意义(P<0.05)。研究组IGF-Ⅰ和IGF-Ⅱ呈正相关,IGF-Ⅰ、IGF-Ⅱ均与IGFBP-1呈负相关(P<0.05)。结论IGF-Ⅰ、IGF-Ⅱ、IGFBP-1与HDCP的发生和病情严重程度密切相关。     

Optimizing dietary fat in a weight-loss trial requires advice based on a structured “whole-of-diet” model

Dietary trials may link macronutrient intakes to health outcomes, but adherence to dietary targets requires advice based on an understanding of food composition and consumption patterns. Using data from a weight loss trial, we hypothesized that structured advice would be required for significant fat modification to occur. We compared participants' food choice patterns in response to advice based on a structured “whole-of-diet” model vs a general approach to healthy eating. Overweight participants (n = 122) were randomized to 2 advice arms (saturated fat [SFA] < 10% energy [E]): (1) general low fat (LF) control—(a) isoenergy, (b) −2000 kJ; and (2) structured LF high polyunsaturated fat (PUFA) (∼10% energy PUFA; PUFA to SFA ratio ≥1) (LF-PUFA)—(a) isoenergy, (b) −2000 kJ. Intakes of E and fat and fat from food groups (percentage of total fat intake) were compared at baseline, 3 months, P < .05. Baseline diets were similar, with most fat from high-SFA foods (59%): meat and milk-based staple meals and high-fat snacks. By 3 months, all groups reduced E and met the SFA target. Polyunsaturated fat targets were met by the LF-PUFA groups only (P < .001), enabling targeted between-group differences. In response to general advice, LF groups simply switched to LF alternatives of the same foods (P < .05). In comparison, LF-PUFA groups shifted fat intake to high-PUFA choices (54%), consuming more fat than controls from nuts (P < .001), whole grains (P < .001), and oils and spreads (P < .05). Significant reductions in E were achieved regardless of advice, but significant shifts in dietary fat profile relied on structured whole-of-diet advice on a range of meal and snack food sources of fat subtypes.     

Are insulin-like growth factor and its binding proteins 1 and 3 clinically useful as markers of malnutrition, sarcopenia and inflammation in end-stage renal disease?

INTRODUCTION: Malnutrition is common in end-stage renal disease (ESRD) and affects both morbidity and mortality. The growth hormone-dependent insulin-like growth factor (IGF)-I may be a good marker of malnutrition because of its short half-life. In the present study, we investigate the influence of decreasing residual renal function as well as of chronic inflammation on the IGF system to assess its usefulness in this patient group. PATIENTS AND METHODS: Cross-sectional analysis of 220 ESRD patients (140 males) with a mean age of 52+/-1 years. Biochemical analyses of insulin, IGF-I, IGFBP-1, IGFBP-3, IL-6, high sensitivity (hs)-CRP and other routine markers. Malnutrition status was recorded using subjective global assessment (SGA), body mass index, estimated protein intake from nitrogen appearance (nPNA), handgrip strength (HGS) and insulin resistance (HOMA-IR). Dual energy X-ray absorptiometry was used to assess body composition. RESULTS: Both IGF-I and IGFBP-1 showed significant and opposite correlations with most markers of nutritional status, including SGA (rho=-0.29 and 0.27; P<0.001), nPNA (rho=0.18 and -0.22; P<0.05), S-creatinine (rho=0.19 and -0.19; P<0.01) and HGS (rho=0.21 and -0.25; P<0.01). IFG-I was strongly correlated with IGFBP-3 (rho=0.62; P<0.001) and inversely correlated with IGFBP-1 (rho=0.44; P<0.001). Both IGF-I and IGFBP-3, but not IGFBP-1, were significantly correlated with age (rho=-0.25 for IGF-I and -0.35 for IGFBP-3; P<0.001) and hsCRP (rho=-0.21 and -0.32; P<0.01). In multivariate analysis, SGA and s-albumin were independent predictors of both IGF-I and IGFBP-1. CONCLUSION: Both IGF-I and IGFBP-1 appear to correlate well with markers of protein-energy malnutrition and sarcopenia. However, IGF-I is also influenced by age, whereas IGFBP-1 is influenced by glucose metabolism. IGFBP-3 does not correlate with nutritional status in ESRD, perhaps because of a strong association with inflammation.     

Dietary fat and menstrual-cycle effects on the erythrocyte ghost insulin receptor in premenopausal women

The effect of high- and low-fat diets with different levels of fatty acid unsaturation on insulin receptors of erythrocyte ghosts was studied during different phases of the menstrual cycle in 31 healthy premenopausal women. Subjects were divided into two groups and consumed controlled diets containing 39% fat with a ratio of polyunsaturated to saturated fatty acids (P:S) of either 0.30 or 1.00 for four menstrual cycles. They were switched to 19% fat at the same P:S for another four cycles. Fasting blood samples were collected during the follicular and luteal phases. Insulin receptors were measured from right-side-out ghosts. Insulin binding was significantly lower due to fewer receptors when subjects were fed the low-fat, high-carbohydrate diet compared with the high-fat, low-carbohydrate diet. There was no significant effect of level of unsaturation or time of menstrual cycle on insulin binding. Thus, insulin receptors on erythrocytes respond to dietary lipids.     

Differential Development of Glucose Intolerance and Pancreatic Islet Adaptation in Multiple Diet Induced Obesity Models

Background: The C57BL/6 mouse fed a high fat diet is a common and valuable model in experimental studies of obesity and type 2 diabetes (T2D). Different high fat diets are used and in order to determine which diet produces a model most accurately resembling human T2D, they need to be compared head-to-head. Methods: Four different diets, the 60% high fat diet (HFD) and the 58% high fat-high sucrose Surwit diet (HFHS) and their respective controls, were compared in C57BL/6J mice using glucose tolerance tests (IVGTT) and the euglycemic clamp. Results: Mice fed a HFD gained more weight than HFHS fed mice despite having similar energy intake. Both high fat diet models were glucose intolerant after eight weeks. Mice fed the HFD had elevated basal insulin, which was not seen in the HFHS group. The acute insulin response (AIR) was unchanged in the HFD group, but slightly increased in the HFHS diet group. The HFHS diet group had a threefold greater total insulin secretion during the IVGTT compared to its control, while no differences were seen in the HFD group. Insulin sensitivity was decreased fourfold in the HFD group, but not in the HFHS diet group. Conclusion: The HFD and HFHS diet models show differential effects on the development of insulin resistance and beta cell adaptation. These discrepancies are important to acknowledge in order to select the appropriate diet for specific studies.     

IGF-1/IGFBP-1与妊娠期糖尿病的相关性

目的:探讨妊娠24～28周孕妇外周IGF-1/IGFBP-1与GDM的相关性,为寻找早期预测GDM的生物学指标提供前期研究。方法:妊娠24～28周GDM孕妇35例为实验组,同期NGT孕妇30例为对照组。采用酶联免疫吸附法检测孕妇外周血IGF-1及IGFBP-1表达水平。结果:①实验组血清IGF-1水平较对照组低,差异有统计学意义(t=-5.71,P<0.05),实验组血清IGFBP-1水平较对照组高,差异有统计学意义(t=2.60,P<0.01)。②IGF-1与IGFBP-1成负相关(r=-0.559 85,P<0.000 1)。结论:孕妇外周血IGF-1/IGFBP-1是调节血糖的重要因素,其平衡失调是介导IR导致GDM患者糖耐量异常的重要机制。     

Glucose Homeostasis Variables in Pregnancy versus Maternal and Infant Body Composition

Intrauterine factors influence infant size and body composition but the mechanisms involved are to a large extent unknown. We studied relationships between the body composition of pregnant women and variables related to their glucose homeostasis, i.e., glucose, HOMA-IR (homeostasis model assessment-insulin resistance), hemoglobin A_1c and IGFBP-1 (insulin-like growth factor binding protein-1), and related these variables to the body composition of their infants. Body composition of 209 women in gestational week 32 and of their healthy, singleton and full-term one-week-old infants was measured using air displacement plethysmography. Glucose homeostasis variables were assessed in gestational week 32. HOMA-IR was positively related to fat mass index and fat mass (r² = 0.32, p < 0.001) of the women. Maternal glucose and HOMA-IR values were positively (p ≤ 0.006) associated, while IGFBP-1was negatively (p = 0.001) associated, with infant fat mass. HOMA-IR was positively associated with fat mass of daughters (p < 0.001), but not of sons (p = 0.65) (Sex-interaction: p = 0.042). In conclusion, glucose homeostasis variables of pregnant women are related to their own body composition and to that of their infants. The results suggest that a previously identified relationship between fat mass of mothers and daughters is mediated by maternal insulin resistance.     

Soy protein- and casein-based weaning diets differ in effects on food intake and blood glucose regulation in male Wistar rats

The effect of weaning male Wistar rats to AIN-93G diets based on casein (C) and soy protein (S) on blood glucose and food intake (FI) regulation was determined. In experiment 1, male Wistar rats (n = 21 per group) received either C or S AIN-93G diets for 7 weeks. In experiment 2, 3 groups of rats were formed (n = 21 per group). The C followed by the S diet group (CS) was weaned to the C diet for 6 weeks followed by the S diet for another 7 weeks. Diet sequence was the reverse for the S followed by the C diet group (SC). The control group (CC) received the C diet throughout 13 weeks. Body weight and cumulative FI were not affected by diet in either experiment. In experiment 1, in fasted rats, S preloads reduced FI for 1 hour more in the C diet group (P < .05), but response to C preloads was not affected by diet. A cholecystokinin A receptor blocker prevented FI reduction by S in rats fed C but not S diet (P < .05). At week 7, rats fed the S diet had higher plasma insulin (67%) (P < .005), glucose (30%) (P < .05) and homeostatic model assessment of insulin resistance index (75%) (P < .005). In experiment 2, FI at weeks 6 and 12 was, again, suppressed most strongly by S preloads in rats fed the C diet (P < .05). At week 13, S and C preloads increased insulin and the insulin/glucose ratio (P < .05), but no differences were found due to preload or diet composition. In conclusion, differences in the effects of first diet exposure to the AIN-93G diets on blood glucose did not persist through either diet change or time. In contrast, protein composition of the most recent diet, but not time, affected FI regulation in response to protein preloads.     

Differential effects of high-fat-diet rich in lard oil or soybean oil on osteopontin expression and inflammation of adipose tissue in diet-induced obese rats

Purpose

To examine the effect of different dietary fat types on osteopontin (OPN) expressions and inflammation of adipose tissues in diet-induced obese rats.

Methods

Male Sprague–Dawley rats were randomly assigned to one control group fed standard diet (LF, n = 10) and two high-fat diet groups fed isoenergy diet rich in lard or soybean oil (HL or HS, n = 45 each). Diet-induced obese rats in HL and HS group were then subdivided into two groups either continuously fed high-fat diet or switched to low-fat diet for 8 more weeks. Fasting serum glucose, insulin, and OPN concentrations were assayed and QUICKI was calculated; the expression of OPN, IL-6, IL-10, TNF-α, NF-κB, and F4/80 in adipose tissue was determined.

Results

Both high-fat diets lead to comparable development of obesity characterized by insulin resistance and adipose tissue inflammation. Obese rats continuously fed high-fat diet rich in lard oil exhibited the highest fasting serum insulin level and adipose tissue OPN, F4/80, TNF-α, and NF-κB expression level. In both high-fat diet groups, switching to low-fat diet resulted in less intra-abdominal fat mass, decreased expression of F4/80, TNF-α, and NF-κB, while decreased OPN expression was only observed in lard oil fed rats after switching to low-fat diet.

Conclusions

Reducing diet fat or replacing lard oil with soybean oil in high-fat diet alleviates obesity-related inflammation and insulin resistance by attenuating the upregulation of OPN and macrophage infiltration into adipose tissue induced by high-fat diet.     

Associations of the SREBP-1c gene polymorphism with gender-specific changes in serum lipids induced by a high-carbohydrate diet in healthy Chinese youth

We investigated the possible association between the sterol regulatory element-binding protein-1c gene (SREBP-1c) rs2297508 polymorphism and the changes in lipid profiles in a high-carbohydrate and low-fat (high-CHO/LF) diet in a Chinese population well characterized by a lower incidence of coronary heart disease and a diet featuring higher carbohydrate and lower fat. Fifty-six healthy youth (aged 22.89?± 1.80?years) were given wash-out diets of 31% fat and 54% carbohydrate for 7?days, followed by the high-CHO/LF diet of 15% fat and 70% carbohydrate for 6?days, without total energy restriction. Fasting blood samples were collected. Serum variables of lipid and glucose metabolism after the wash-out and high-CHO/LF diets, as well as the rs2297508 polymorphism, were analyzed. Compared with the male subjects on the wash-out diet, significantly elevated levels of high-density lipoprotein cholesterol (HDL-C) and decreased levels of apolipoprotein B-100 were observed in the male carriers of the C allele after the high-CHO/LF diet. In the female subjects, significantly increased triacylglycerol levels, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were found in the GG genotype after the high-CHO/LF diet. These results suggest that the C allele of the rs2297508 polymorphism is associated with a retardation of the increases in serum triacylglycerol, serum insulin, and HOMA-IR in females and with the elevated serum HDL-C in males after the high-CHO/LF diet.