Enhanced glucose uptake into adipose tissue induced by early growth restriction augments excursions in plasma leptin response evoked by changes in insulin status

The influence of down-regulation of suppressor of cellular signaling proteins by RNAi on glucose transport of intrauterine growth retardation rats

Intrauterine growth retardation (IUGR) has been linked to metabolic syndrome including insulin resistance, and overexpression of suppressors of cytokine signaling (SOCSs) proteins is thought to be associated with increased whole-body insulin sensitivity. The insulin-resistant IUGR rat model was established by maternal food restriction (about 30% of the normal rats). The weight, length, and homeostasis model assessment of insulin resistance (HOMA-IR) of IUGR-born rats was higher than the control group. Insulin receptor substrate (IRS)-1 expression decreased, whereas SOCS-1 and SOCS-3 increased in the skeletal muscle of IUGR rats compared with the control group. The recombination plasmids PGPU6/GFP/Neo-SOCS-1small hairpin RNA (shRNA) and PGPU6/GFP/Neo-SOCS-3shRNA were transfected into skeletal muscle cells, and the shRNAs efficiently inhibited the expression of SOCS-1 and SOCS-3. Insulin-stimulated glucose transporter-4 (GLUT4) translocation was also dramatically increased. In conclusion, these data provide additional information on the mechanism of insulin resistance associated with IUGR. Down-regulation of SOCS-1 and SOCS-3 ameliorates the capacity of glucose transport and provides a potential gene therapy approach to managing metabolic syndrome.

Effect of nutritional recovery with soybean flour diet on body composition, energy balance and serum leptin concentration in adult rats

BACKGROUND

Malnutrition in early life is associated with obesity in adulthood and soybean products may have a beneficial effect on its prevention and treatment. This study evaluated body composition, serum leptin and energy balance in adult rats subjected to protein restriction during the intrauterine stage and lactation and recovering on a soybean flour diet.

METHODS

Five groups of the Wistar strain of albino rats were used: CC, offspring born to and suckled by mothers fed a control diet and fed the same diet after weaning; CS, offspring born to and suckled by mothers fed a control diet and fed a soybean diet with 17% protein after weaning; LL, offspring of mothers fed a low protein diet and fed the same diet after weaning; LC, offspring of mothers fed a low protein diet, but fed a control diet after weaning; LS, offspring of mothers fed a low protein diet, but fed a soybean diet with 17% protein after weaning. Food intake, body, perirenal and retroperitoneal adipose tissue were measured in grams. Leptin was quantified using the Enzyme Linked Immuno Sorbent Assay (ELISA) and insulin by radioimmunoassay (RIA). Carcass composition was determined by chemical methods and energy expenditure was calculated by the difference between energy intake and carcass energy gain. Data were tested by analysis of variance (ANOVA).

RESULTS

The LC and LS groups had higher energetic intake concerning body weight, lower energy expenditure, proportion of fat carcass and fat pads than CC and CS groups. The LS group showed reduced body weight gain and lower energy efficiency, which was reflected in less energy gain as protein and the proportion of carcass protein, and lower energy gain as lipid than in the LC groups, although both groups had eaten the same amount of diet and showed equal energy expenditure. Serum leptin did not differ among groups and was unrelated to food or energy intake and energy expenditure. Serum insulin was higher in the LS than in the LC group.

CONCLUSION

Protein restriction during intrauterine life and lactation periods did not provoke obesity in adulthood. Nutritional recovery with soybean diet decreased the body weight at the expense of lower energy efficiency with repercussion on lean mass.

Intrauterine growth restriction and adult disease: the role of adipocytokines

Intrauterine growth restriction (IUGR) is the failure of the fetus to achieve his/her intrinsic growth potential, due to anatomical and/or functional disorders and diseases in the feto-placental-maternal unit. IUGR results in significant perinatal and long-term complications, including the development of insulin resistance/metabolic syndrome in adulthood. The thrifty phenotype hypothesis holds that intrauterine malnutrition leads to an adaptive response that alters the fetal metabolic and hormonal milieu designed for intrauterine survival. This fetal programming predisposes to an increased susceptibility for chronic diseases. Although the mechanisms controlling intrauterine growth are poorly understood, adipose tissue may play an important role in linking poor fetal growth to the subsequent development of adult diseases. Adipose tissue secretes a number of hormones, called adipocytokines, important in modulating metabolism and recently involved in intrauterine growth. This review aims to summarize reported findings concerning the role of adipocytokines (leptin, adiponectin, ghrelin, tumor necrosis factor (TNF), interleukin-6 (IL6), visfatin, resistin, apelin) in early life, while attempting to speculate mechanisms through which differential regulation of adipocytokines in IUGR may influence the risk for development of chronic diseases in later life.

Post-weaning protein malnutrition in the rat produces short and long term metabolic impairment, in contrast to earlier and later periods

Malnutrition during gestation and lactation modifies metabolic strategies and leads to metabolic disease in adult life. Studies in human populations suggest that malnutrition during infancy may also induce long term metabolic disorders.

The present study investigated if post-weaning and a late period of development might be sensitive for long term metabolic impairment. Hereto male Wistar rats were malnourished with a low protein diet (6%), during gestation and lactation (MGL), from weaning to 55 days (MPW) or during adulthood from 90 to 120 days (MA). Control rats (C) were fed with a regular diet (23% protein). We determine plasma concentrations of insulin, glucagon, triacylglycerols (TAG), free fatty acids (FFA), and liver glycogen after a Glucose Tolerance Test (GTT).

Independent of the age of onset, malnutrition induced low body weight. Early and post-weaning malnutrition produced impaired glucose tolerance and low values of TAG, also in MPW induced low values of insulin and glucagon. At 90 days, after balanced diet rehabilitation, the MGL group showed a similar glucose tolerance test as the controls but display low values of insulin, while the MPW group exhibited high levels of glucose and TAG, and low values of insulin, glucagon, FFA and hepatic glycogen. At 180 days, after balanced rehabilitation only MPW rats showed metabolic alterations. Malnutrition during adult life (MA) did not produce metabolic disturbances. Surprisingly the results uncover the post-weaning stage as a vulnerable period to malnutrition that induces long lasting metabolic alterations and deficiency in pancreatic function.

Evidence for relatively greater subcutaneous fat deposition in stunted girls in the North West Province, South Africa, as compared with non-stunted girls

OBJECTIVE

We examined differences in body composition between stunted and non-stunted girls, with adjustments for confounding factors.

METHODS

A cross-sectional study was conducted in a representative sample of 478 African school girls, ages 10 to 15 y, in the North West Province, South Africa. Height, weight, skinfold thicknesses, and waist and mid upper arm circumferences were measured by trained biokineticists using standard methods. Trained field workers measured dietary intakes by 24-h recall, and physical activity was measured by using the physical activity recall of the previous day. Body mass index and physical activity category were calculated.

RESULTS

Stunted girls had significantly lower weight and skinfold thicknesses than did non-stunted ones. After including the covariates: age, years since menarche, school, type of housing, dietary energy and fat intakes, physical activity category, body weight, and stratum of urbanization in analysis of variance, the mean sum of triceps skinfold and subscapular skinfold thicknesses of stunted girls was greater than that of the non-stunted girls (P < 0.002). Stunted subjects were less active than non-stunted ones.

CONCLUSION

This manifestation of relatively more subcutaneous fat and greater waist circumference in stunted girls may be involved in the development of obesity among black women in South Africa.

Exposure to maternal diabetes is associated with altered fetal growth patterns: A hypothesis regarding metabolic allocation to growth under hyperglycemic-hypoxemic conditions

The prevalence of diabetes is rising worldwide, including women who grew poorly in early life, presenting intergenerational health problems for their offspring. It is well documented that fetuses exposed to maternal diabetes during pregnancy experience both macrosomia and poor growth outcomes in birth size. Less is known about the in utero growth patterns that precede these risk factor expressions. Fetal growth patterns and the effects of clinical class and glycemic control were investigated in 37 diabetic pregnant women and their fetuses and compared to 29 nondiabetic, nonsmoking maternal/fetal pairs who were participants in a biweekly longitudinal ultrasound study with measurements of the head, limb, and trunk dimensions. White clinical class of the diabetic women was recorded (A2-FR) and glycosylated hemoglobin levels taken at the time of measurement assessed glycemic control (median 6.9%, interquartile range 5.6-9.2%). No significant difference in fetal weight was found by exposure. The exposed sample had greater abdominal circumferences from 21 weeks (P < or = 0.05) and shorter legs, but greater upper arm and thigh circumferences accompanied increasing glycemia in the second trimester. In the third trimester, exposed fetuses had a smaller slope for the occipital frontal diameter (P = 0.00) and were brachycephalic. They experienced a proximal/distal growth gradient in limb proportionality with higher humerus / femur ratios (P = 0.04) and arms relatively long by comparison with legs (P = 0.02). HbA1c levels above 7.5% accompanied shorter femur length for thigh circumference after 30 gestational weeks of age. Significant effects of diabetic clinical class and glycemic control were identified in growth rate timing. These growth patterns suggest that hypoxemic and hyperglycemic signals cross-talk with their target receptors in a developmentally regulated, hierarchical sequence. The increase in fetal fat often documented with diabetic pregnancy may reflect altered growth at the level of cell differentiation and proximate mechanisms controlling body composition. These data suggest that the maternal-fetal interchange circuit, designed to share and capture resources on the fetal side, may not have had a long evolutionary history of overabundance as a selective force, and modern health problems drive postnatal sequelae that become exacerbated by increasing longevity.