Perinatal origin of adult disease

N-3 (Omega-3) Fatty Acids: Effects on Brain Dopamine Systems and Potential Role in the Etiology and Treatment of Neuropsychiatric Disorders

BACKGROUND & OBJECTIVE

A number of neuropsychiatric disorders, including Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder, and, to some extent, depression, involve dysregulation of the brain dopamine systems. The etiology of these diseases is multifactorial, involving genetic and environmental factors. Evidence suggests that inadequate levels of n-3 (omega- 3) polyunsaturated fatty acids (PUFA) in the brain may represent a risk factor for these disorders. These fatty acids, which are derived from the diet, are a major component of neuronal membranes and are of particular importance in brain development and function. Low levels of n-3 PUFAs in the brain affect the brain dopamine systems and, when combined with appropriate genetic and other factors, increase the risk of developing these disorders and/or the severity of the disease. This article reviews the neurobiology of n-3 PUFAs and their effects on dopaminergic function.

CONCLUSION

Clinical studies supporting their role in the etiologies of diseases involving the brain dopamine systems and the potential of n-3 PUFAs in the treatment of these disorders are discussed.

The biological basis and clinical significance of hormonal imprinting, an epigenetic process

The biological phenomenon, hormonal imprinting, was named and defined by us (Biol Rev, 1980, 55, 47-63) 30 years ago, after many experimental works and observations. Later, similar phenomena were also named to epigenetic imprinting or metabolic imprinting. In the case of hormonal imprinting, the first encounter between a hormone and its developing target cell receptor-usually at the perinatal period-determines the normal receptor-hormone connection for life. However, in this period, molecules similar to the target hormone (members of the same hormone family, synthetic drugs, environmental pollutants, etc), which are also able to bind to the receptor, provoke faulty imprinting also with lifelong-receptorial, behavioral, etc.,-consequences. Faulty hormonal imprinting could also be provoked later in life in continuously dividing cells and in the brain. Faulty hormonal imprinting is a disturbance of gene methylation pattern, which is epigenenetically inherited to the further generations (transgenerational imprinting). The absence of the normal or the presence of false hormonal imprinting predispose to or manifested in different diseases (e.g., malignant tumors, metabolic syndrome) long after the time of imprinting or in the progenies.

[Hormonal imprinting--the unforeseeable future]

Hormonal imprinting takes place at the first encounter between the developing receptor and the target hormone, perinatally, causing life-long changes in the binding capacity of the receptor and the indexes influenced by it. Perinatal hormonal imprinting is absolutely needed for the maturation of receptor, however, at the same time, molecules similar to the target hormone (related hormones, synthetic drugs acting at receptor level, chemicals, environmental pollutants etc.) can cause faulty imprinting, also with (morphological, biochemical, receptorial, behavioral) consequences for life. Although imprinting is characteristic and inevitable perinatally, it can be provoked in any period of life in developing cells, especially at the weanling and adolescent age (late imprinting). There is no gene mutation during imprinting, however, the methylation pattern of the genes changes and that inherits epigenetically the imprinting, which is manifested in disposition to diseases or in diseases (e.g. tumor formation, metabolic syndrome). Imprinting is inherited between generations that could cause--in the present chemical world--evolutionary consequences. Thus, medicaments or preventive drugs, e.g. pregnancy protecting drugs or oral contraceptive pills should be given cautiously, especially in the critical periods, considering that consequences are manifested always after a long period (sometimes decades) or in the next generations.

Causes and consequences of early-life health

We examine the consequences of child health for economic and health outcomes in adulthood, using height as a marker of childhood health. After reviewing previous evidence, we present a conceptual framework that highlights data limitations and methodological problems that complicate the study of this topic. We then present estimates of the associations between height and a range of outcomes--including schooling, employment, earnings, health, and cognitive ability--measured in five data sets from early to late adulthood. These results indicate that, on average, taller individuals attain higher levels of education. Height is also positively associated with better economic, health, and cognitive outcomes. These associations are only partially explained by the higher average educational attainment of taller individuals. We then use data from the National Longitudinal Survey of Youth 1979 Children and Young Adults survey to document the associations between health, cognitive development, and growth in childhood. Even among children with the same mother, taller siblings score better on cognitive tests and progress through school more quickly. Part of the differences found between siblings arises from differences in their birth weights and lengths attributable to mother's behaviors while pregnant. Taken together, these results support the hypothesis that childhood health influences health and economic status throughout adulthood.

Hormonal imprinting: phylogeny, ontogeny, diseases and possible role in present-day human evolution

Hormonal (chemical) imprinting which was first observed (and named) by us in the seventies of the last century, is a general biological phenomenon which takes place when the developing receptor meets its target hormone for the first time. Under the effect of imprinting, receptors mature and reach their maximal binding capacity. It also influences the cells' hormone production and different functions depending on receptors and hormones. Hormonal imprinting is present already at the unicellular level causing the development of specific receptors and helping the easier recognition of useful or harmful surrounding molecules. The phenomenon is an important factor in the survival of the species, as the effect of imprinting is transmitted to the progeny cell generations. At the same time it possibly helps the selection of molecules which are suitable for acting as hormones in higher ranked animals. In mammals, hormonal imprinting takes place perinatally and determines the function of receptor-signal-transduction systems as well as hormone production for life. However, there are other critical imprinting periods for continuously developing cells. Excess of the target hormones or presence of foreign molecules which are able to bind to the receptors, provoke faulty imprinting in the critical periods with life-long morphological, biochemical, functional or behavioural consequences. As many receptor-bound foreign molecules are used as medical treatments and many such molecules are present around us and inside us as environmental pollutants, they--causing faulty imprinting--are able to predispose the (human) organism to cardiovascular, endocrine, metabolic and cancerous diseases. It seems likely that this effect is connected with disturbance of DNA methylation process in the critical periods of life. There are some signs of the transgenerational effect of faulty imprinting and this could be manifested in the evolution of humans by an epigenetic route.

Fetal growth patterns in fetuses of women with pregestational diabetes mellitus

OBJECTIVE

To assess the effect of glucose control on the rate of growth of fetuses in women with pregestational diabetes mellitus (Types 1 and 2).

METHODS

All pregestational diabetic women booked at Mater Mothers' Hospital, Brisbane, Australia, between 1 January 1994 and 31 December 2002, were included. Pregnancies with congenital fetal anomalies, multiple pregnancies, and pregnancies terminated prior to 20 weeks' gestation were excluded. Dating scans were performed before 14 weeks' gestation and serial scans were performed at 18, 24, 28, 32 and 36 weeks. Fetal parameters, including biparietal diameter, femur length and abdominal circumference, were recorded. The daily growth rates for biparietal diameter, femur length, and fetal abdominal area were calculated and compared with those in a low-risk (non-diabetic) population. The growth rates in fetuses of women with satisfactory diabetic control (HbA1c < 6.5%) and unsatisfactory control (HbA1c > or = 6.5%) in the three trimesters were compared.

RESULTS

A total of 174 diabetic pregnancies were included and a total of 997 ultrasound scans were performed. The growth rates for fetuses of mothers with diabetes mellitus were significantly higher than for those in the low-risk population. The z-scores for biparietal diameter, femur length, and fetal abdominal area were 0.18, 0.59 and 1.44, respectively. Fetuses of diabetic mothers with high HbA1c in the first trimester had significantly greater fetal abdominal area growth rate than those with normal HbA1c (fetal abdominal area z-score of 1.7 vs. 0.75, P = 0.009). Although the fetal abdominal area z-scores in fetuses of diabetic mothers with high HbA1c in the second or third trimesters were also higher than those with normal HbA1c levels, the differences did not reach statistical significance. Maternal obesity did not influence the fetal growth rate.

CONCLUSION

The rate of growth of fetuses of diabetic mothers differs from that of the normal population. Growth acceleration persists until the late third trimester. Moreover, periconceptional glucose control appears to have a significant effect on accelerated growth of the fetal abdominal area.

Translating pharmacogenetics and pharmacogenomics into drug development for clinical pediatrics and beyond

Pharmacogenetic and pharmacogenomic investigations conducted in children must consider that human development from conception through to adolescence is a rapidly changing, dynamic process. An improved understanding of the gene networks that are involved in growth and development and of the unintended consequences of modulating those systems could provide insights into the susceptibility of an individual to drug-induced birth defects and to pediatric adverse drug reactions. Furthermore, these technologies potentially present the opportunity to develop novel, effective treatments for childhood diseases and for adult diseases that manifest primarily during childhood. The lack of pharmacogenetic and pharmacogenomic investigations in children and the potential to impact on all age groups provides a considerable incentive to invest in this area of research.

Prenatal exposure to IL-1beta results in disturbed skeletal growth in adult rat offspring

Events occurring early in life or prenatally are able to play important roles in the pathogenesis of diseases in adult life. Different sorts of stress or hormonal influences, during particular periods of pregnancy, may result in persistent or transient changes in physiology. IL-1 is a multifunctional cytokine that is involved in bone metabolism. The aim of the present study was to investigate whether exposure to IL-1beta during fetal life has any effect on skeletal growth or bone mineral density in adult rat offspring. Pregnant rats were given intraperitoneal injections of IL-1beta, 1 microg/rat, or saline on days 8, 10, and 12 of gestation. Male IL-1-exposed offspring showed reduced height, areal bone mineral density, and bone mineral content at vertebra L5. Tibial length was reduced in both male and female offspring. Peripheral quantitative computed tomography analyses revealed reduced cortical bone mineral content caused by a decreased cortical cross-sectional area as a result of a decreased cortical thickness, whereas there was no reduction in the amount of trabecular bone in the tibia of male offspring. Our results demonstrate that prenatal exposure to IL-1 can induce specific programming of skeletal tissue. In conclusion, prenatal IL-1 exposure results in decreased skeletal growth and a reduced amount of cortical bone but unchanged trabecular bone mineral density in adult rat offspring.