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Dr. Donovan’s laboratory conducts basic and translational research in the area of pediatric nutrition.  The early neonatal period is a critical phase of development during which time nutrition can exert both short and long-term effects.  We take a multidisciplinary approach incorporating whole animal, tissue, cellular and molecular analytical approaches. We use sophisticated cell biological and molecular approaches, such as gene microarray, immunohistochemistry, confocal microscopy and flow cytometry to assess host gene expression and immune response and RNA and DNA sequencing for microbial gene expression.  On-going research is focused in three areas:  optimizing intestinal development of neonates, prevention of childhood obesity and determinants of picky eating in 2-5 year-old children.

Human milk is the optimal form of nutrition for the human infant; however, most babies in the U.S. are not breastfed or only receive breast milk for a short period of time. Formulas provide adequate nutrition, but differ in nutrient composition from breast milk and do not contain the bioactive components (e.g. hormones and growth factors) that are present in breast milk. How these various components influence development and their long-term consequences is largely unknown.
Therefore, our overall research in this area is directed at understanding the regulation of neonatal development by components present in human milk and infant formula. The intestine is a multifunctional organ with key roles in nutrition and protection of the host from pathogenic bacteria.  In addition, the intestine is also one of the largest immune organs in the body and plays major endocrine and exocrine roles. Thus, postnatal development of the intestine is critical to the well-being of the infant. A primary focus in the laboratory is on the identification of clinically-relevant biomarkers and the development of efficacious therapies (including optimized formulas) to enhance gut function of neonates. Studies incorporate human infants as well as a variety of porcine models of human disease, including parenteral nutrition, rotavirus diarrhea and inflammation. Current research projects include: Clinical and epidemiological data support differences in intestinal development and lower incidence of gastrointestinal infections and longer-term intestinal immune dysfunction in breastfed than formula-fed infants.  On-going research is comparing differences in intestinal gene expression between neonates fed mother’s milk vs. formula.  We examine gene expression in exfoliated intestinal epithelial cells in collaboration with Dr. Robert Chapkin (Texas A&M University).  Recent studies are exploring the relationship between host gene expression and the composition of the microbiota and their gene expression (metagenomics). Human milk contains high concentrations (7-12 g/L) of structurally diverse (up to 200 different structures) of human milk oligosaccharides (HMO).  HMO benefit the infant by promoting the growth of beneficial bacteria and inhibiting the attachment of pathogens to the intestinal lining.).  Cow milk, which is used to make most infant formulas, has less than 1 g/L of oligosaccharides. As an alternative to HMOs, synthetic prebiotics are currently added to infant formulas.   Prebiotics are non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth of specific healthful bacteria in the colon. On-going research is studying how HMO and prebiotics influence intestinal gene expression, immune development and microbial colonization. Human milk contains bioactive peptides and proteins that are resistant to digestion and exert physiological functions within the neonate.  These proteins include growth factors, immune regulating proteins such as immunoglobulins, lactoferrin and lysozyme.  Many of these proteins are also present in bovine milk and can be isolated for potential addition to infant formula.  On-going research is evaluating the efficacy of bovine lactoferrin and osteopontin as potential formula additives. New research suggests that the early pre-school years are a critical period for weight-related behavior habit formation, obesity risk assessment, and prevention. The rate of overweight among 2 to 5 year olds rose from 5.0% to 13.9% between 1976 and 2004 and an increase in weight velocity between ages 2 and 5 is a stronger predictor of adult overweight than birth weight. As a founding member of the STRONG Kids Program, Dr. Donovan is involved in a comprehensive and interdisciplinary approach to the study of childhood obesity and health. STRONG Kids is a longitudinal panel study of ~400 preschool aged children enrolled in day care and their parents. The purpose of the research is to obtain rich and integrative data in order to test theory-driven models of predictors of childhood overweight and obesity over time. The goal is to apply this knowledge to develop tailored prevention and intervention programs for families and children that promote healthy development, that are evidence based, and that are grounded in developmental theory. In the first 2 years of life, infants transition from liquid diets, through infant foods to primarily adult foods.  These new sensory experiences, coupled with developmental changes, such as neophobia, can set up a situation where toddlers and children restrict their food choices – a phenomenon referred to a “picky eating”.  Indeed the percentage of parents identified as picky is ~ 50% at 2 years of age.  In collaboration with Dr. Soo Lee (Dept FSHN), we are investigating the determinants of picky eating, including parental perception, food availability and parenting style.