Developmental Origins of Disease

At any age one can become sick, however, it is pathetic when someone is born with a disease that too which is not expressed immediately. Such diseases show up weeks later and some years later. The causes of such diseases are multifactorial. In this mini-review, we are trying to focus on some important risk factors which should be considered before getting pregnant; in some genetic disorders, genetic analysis is important, even before pregnancy, for others prenatal diagnosis is recommended.

Early-life DNA methylation profiles are indicative of age-related transcriptome changes

Background Alterations to cellular and molecular programs with brain aging result in cognitive impairment and susceptibility to neurodegenerative disease. Changes in DNA methylation patterns, an epigenetic modification required for various CNS functions are observed with brain aging and can be prevented by anti-aging interventions, but the relationship of altered methylation to gene expression is poorly understood. Results Paired analysis of the hippocampal methylome and transcriptome with aging of male and female mice demonstrates that age-related differences in methylation and gene expression are anti-correlated within gene bodies and enhancers. Altered promoter methylation with aging was found to be generally un-related to altered gene expression. A more striking relationship was found between methylation levels at young age and differential gene expression with aging. Highly methylated gene bodies and promoters in early life were associated with age-related increases in gene expression even in the absence of significant methylation changes with aging. As well, low levels of methylation in early life were correlated to decreased expression with aging. This relationship was also observed in genes altered in two mouse Alzheimer’s models. Conclusion DNA methylation patterns established in youth, in combination with other epigenetic marks, were able to accurately predict changes in transcript trajectories with aging. These findings are consistent with the developmental origins of disease hypothesis and indicate that epigenetic variability in early life may explain differences in aging trajectories and age-related disease.

Periconceptional environment and the developmental origins of disease

The concept emerging from Professor David Barker’s seminal research on the developmental origins of later-life disease has progressed in many directions since it was first published. One critical question being when during gestation might environment alter the developmental programme with such enduring consequences. Here, we review the growing consensus from clinical and animal research that the period around conception, embracing gamete maturation and early embryogenesis might be the most vulnerable period. We focus on four types of environmental exposure shown to modify periconceptional reproduction and offspring development and health: maternal overnutrition and obesity; maternal undernutrition; paternal diet and health; and assisted reproductive technology. These conditions may act through diverse epigenetic, cellular and physiological mechanisms to alter gene expression and cellular signalling and function in the conceptus affecting offspring growth and metabolism leading to increased risk for cardiometabolic and neurological disease in later life.

Establishing a three-generation prospective study: Bogalusa daughters

Objective:The Developmental Origins of Disease hypothesis has spurred increased interest in how prenatal exposures affect lifelong health, while mechanisms such as epigenetics may explain the multigenerational influences on health. Such factors are not well captured within conventional epidemiologic study designs. We explored the feasibility of collecting information on the offspring and grand-offspring of participants in a long-running study.Design:The Bogalusa Heart Study is a study, begun in 1973, of life-course cardiovascular health in a semirural population (65% white and 35% black).Main measures:Female participants who had previously provided information on their pregnancies were contacted to obtain contact information for their daughters aged 12 and older. Daughters were then contacted to obtain reproductive histories, and invited for a clinic or lab visit to measure cardiovascular risk factors.Results:Two hundred seventy-four daughters of 208 mothers were recruited; 81% (223) had a full clinic visit and 19% (51) a phone interview only. Forty-five percent of the daughters were black, and 55% white. Mean and median age at interview was 27, with 15% under the age of 18. The strongest predictors of participation were black race, recent maternal participation in the parent study, and living in or near Bogalusa. Simple correlations for cardiovascular risk factors across generations were between r = 0.19 (systolic blood pressure) and r = 0.39 (BMI, LDL).Conclusion:It is feasible to contact the children of study participants even when participants are adults, and initial information on the grandchildren can also be determined in this manner.

Early life DNA methylation profiles are indicative of age-related transcriptome changes

Alterations to cellular and molecular programs with brain aging result in cognitive impairment and susceptibility to neurodegenerative disease. Changes in DNA methylation patterns, an epigenetic modification required for various CNS functions, are observed with aging and can be prevented by anti-aging interventions, but the functional outcomes of altered methylation on transcriptome profiles are poorly understood with brain aging. Integrated analysis of the hippocampal methylome and transcriptome with aging of male and female mice demonstrates that age-related differences in methylation and gene expression are anti-correlated within gene bodies and enhancers, but not promoters. Methylation levels at young age of genes altered with aging are positively associated with age-related expression changes even in the absence of significant changes to methylation with aging, a finding also observed in mouse Alzheimer’s models. DNA methylation patterns established in youth, in combination with other epigenetic marks, are able to predict changes in transcript trajectories with aging. These findings are consistent with the developmental origins of disease hypothesis and indicate that epigenetic variability in early life may explain differences in age-related disease.

Genome organization: connecting the developmental origins of disease and genetic variation

An adverse early life environment can increase the risk of metabolic and other disorders later in life. Genetic variation can modify an individual’s susceptibility to these environmental challenges. These gene by environment interactions are important, but difficult, to dissect. The nucleus is the primary organelle where environmental responses impact directly on the genetic variants within the genome, resulting in changes to the biology of the genome and ultimately the phenotype. Understanding genome biology requires the integration of the linear DNA sequence, epigenetic modifications and nuclear proteins that are present within the nucleus. The interactions between these layers of information may be captured in the emergent spatial genome organization. As such genome organization represents a key research area for decoding the role of genetic variation in the Developmental Origins of Health and Disease.