The thrifty 'catch-up fat' phenotype: its impact on insulin sensitivity during growth trajectories to obesity and metabolic syndrome

Impact of genetic and epigenetic factors from early life to later disease

There is ample evidence that subtle changes in the early environment, not restricted to the fetal period but expanded to the plastic phase of early development, influence adulthood disease appearance. There is also evidence that genetic background resulting from our evolution is an important contributor to susceptibility to perinatal imprinting. However, rapid adjustment and optimization, at times necessary for survival, require a type of plasticity that the genome sequence alone cannot achieve. Without changing the genomic backbone, epigenetic modulation, in reaction to a given environment, results in functional adaptation of the genomic response. Evolutionally acquired genomic susceptibilities and environmentally induced epigenomic modulations occurring early in life impact on later development of human diseases.

Regulation of fetal growth: consequences and impact of being born small

The first trimester of pregnancy is the time during which organogenesis takes place and tissue patterns and organ systems are established. In the second trimester the fetus undergoes major cellular adaptation and an increase in body size, and in the third trimester organ systems mature ready for extrauterine life. In addition, during that very last period of intrauterine life there is a significant increase in body weight. In contrast to the postnatal endocrine control of growth, where the principal hormones directly influencing growth are growth hormone (GH) and the insulin-like growth factors (IGFs) via the GH-IGF axis, fetal growth throughout gestation is constrained by maternal factors and placental function and is coordinated by growth factors. In general, growth disorders only become apparent postnatally, but they may well be related to fetal life. Thus, fetal growth always needs to be considered in the overall picture of human growth as well as in its metabolic development.

Thrifty energy metabolism in catch-up growth trajectories to insulin and leptin resistance

Catch-up growth early in life (after fetal, neonatal or infantile growth retardation) is a major risk factor for later obesity, type-2 diabetes and cardiovascular diseases. These risks are generally interpreted alongside teleological arguments that environmental exposures which hinder growth early in life lead to programming of 'thrifty mechanisms' that are adaptive during the period of limited nutrient supply (or growth constraint), but which increase risks for diseases during improved nutrition and catch-up growth later in life. This paper addresses this notion of 'thrifty mechanisms' in the light of evidence that catch-up growth is characterized by a disproportionately higher rate of fat gain relative to lean tissue gain, and that such preferential catch-up fat is in part driven by energy conservation mechanisms operating via suppressed thermogenesis. It provides a molecular-physiological framework which integrates emerging insights into mechanisms by which this thrifty 'catch-up fat' phenotype cross-links with insulin and leptin resistance.

How early dietary factors modify the effect of rapid weight gain in infancy on subsequent body-composition development in term children whose birth weight was appropriate for gestational age

BACKGROUND

It is not clear whether the adverse effects of rapid weight gain in infancy are modified by nutrition during the first 2 y of life in term children whose birth weight was appropriate for gestational age (AGA).

OBJECTIVE

We examined the interaction between rapid weight gain and nutrition in infancy and early childhood and their effect on body fat percentage (BF%) trajectories between 2 and 5 y of age.

DESIGN

The study population comprised 249 (51.4% female) term AGA participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study, for whom repeated anthropometric measurements until 5 y of age and information on breastfeeding status and on diet at 12 and 18-24 mo of age were available.

RESULTS

Multilevel model analyses showed that, among rapid growers, those who had been fully breastfed for > or =4 mo had a lower BF% at 2 y of age than did those who had not been fully breastfed for > or =4 mo (beta +/- SE: -1.53 +/- 0.59%; P = 0.009). This difference persisted until 5 y. Furthermore, those rapid growers who had a consistently high fat intake at both 12 and 18-24 mo did not show the expected physiologic decrease in BF% between 2 and 5 y seen in those rapid growers with an inconsistent or consistently low fat intake at these time points (0.73 +/- 0.26%/y; P = 0.006).

CONCLUSIONS

Among rapid growers, full breastfeeding for > or =4 mo is protective against a high BF% at 2 y of age, whereas a consistently high fat intake in the second year of life "inhibits" the physiologic decrease in BF% between 2 and 5 y.

Adipose Tissue: A Metabolic Regulator. Potential Implications for the Metabolic Outcome of Subjects Born Small for Gestational Age (SGA)

Adipose tissue is involved in the regulation of glucose and lipid metabolism, energy balance, inflammation and immune response. Abdominal obesity plays a key role in the development of insulin resistance because of the high lipolytic rate of visceral adipose tissue and its secretion of adipocytokines. Low birth weight subjects are prone to central redistribution of adipose tissue and are at high risk of developing metabolic syndrome, type 2 diabetes and cardiovascular disease. Intrauterine adipogenesis may play a key role in the fetal origin of the pathogenesis of metabolic syndrome, type 2 diabetes and cardiovascular disease. Therefore, knowledge of the behavior of visceral adipose tissue-derived stem cells could provide a greater understanding of the metabolic risk related to intrauterine growth retardation, with potential clinical implications for the prevention of long-term metabolic alterations.

Pathophysiologic mechanisms of obesity and related metabolic disorders: an epidemiologic study using questionnaire and serologic biomarkers

BACKGROUND

It is still unclear whether individuals with the same degree of obesity but different weight histories since young adulthood have different insulin concentration, prevalence of metabolic syndrome components and their clustering.

METHODS

A cross-sectional study was conducted on 3,399 (for weight difference analysis) and 1,879 (for weight fluctuation analysis) Japanese men aged 40-59 years. Weight difference was calculated by subtracting the recalled weight at about 25 years old from the current weight. The root mean square error around the slope of weight on age (weight - RMSE) was calculated by a simple linear regression model, in which the subject's actual weights at ages 20, 25, 30, 40 years and 5 years prior to the study, as well as current weight, were dependent variables against the subject's age as the independent variable. Each metabolic syndrome component was defined as follows: serum triglycerides ≥150 mg/dL; HDL-cholesterol <40 mg/dL; fasting glucose ≥110 mg/dL; and blood pressure ≥140/90 mm Hg.

RESULTS

Those who gained <10%, <20%, or 20% or more in weight had a significantly higher than unity odds ratio of having two or more metabolic syndrome components in relation to those whose weight remained stable: 1.28 (95% confidence interval: 0.95-1.73), 2.49 (1.91-3.24), and 5.30 (3.97-7.07), respectively. Weight-RMSE was significantly and positively associated with fasting insulin concentration independent of current weight, weight-slope or other lifestyle-related factors.

CONCLUSIONS

Metabolic syndrome components would likely tend to cluster more in individuals with large weight gain on a physiologic basis characterized by high fasting insulin concentration. Furthermore, weight fluctuation was suggested to increase the risk of fasting hyperinsulinemia.

Fetal programming of body dimensions and percentage body fat measured in prepubertal children with a 4-component model of body composition, dual-energy X-ray absorptiometry, deuterium dilution, densitometry, and skinfold thicknesses

BACKGROUND

Intrauterine programming of body composition [percentage body fat (%BF)] has been sparsely examined with multiple independent reference techniques in children. The effects on and consequences of body build (dimensions, mass, and length of body segments) are unclear.

OBJECTIVE

The study examined whether percentage fat and relation of percentage fat to body mass index (BMI; in kg/m2) in prepubertal children are programmed during intrauterine development and are dependent on body build. It also aimed to examine the extent to which height can be predicted by parental height and birth weight.

DESIGN

Eighty-five white children (44 boys, 41 girls; aged 6.5-9.1 y) had body composition measured with a 4-component model (n = 58), dual-energy X-ray absorptiometry (n = 84), deuterium dilution (n = 81), densitometry (n = 62), and skinfold thicknesses (n = 85).

RESULTS

An increase in birth weight of 1 SD was associated with a decrease of 1.95% fat as measured by the 4-component model (P = 0.012) and 0.82-2.75% by the other techniques. These associations were independent of age, sex, socioeconomic status, physical activity, BMI, and body build. Body build did not decrease the strength of the associations. Birth weight was a significantly better predictor of height than was self-reported midparental height, accounting for 19.4% of the variability at 5 y of age and 10.3% at 7.8 y of age (17.8% and 8.8% of which were independent of parental height at these ages, respectively).

CONCLUSIONS

Consistent trends across body-composition measurement techniques add strength to the suggestion that percentage fat in prepubertal children is programmed in utero (independently of body build and BMI). It also suggests birth weight is a better predictor of prepubertal height than is self-reported midparental height.