Functional Dyspepsia is a major functional bowel disorder that affects about 15% to 25% of the U.S. population. The two primary symptoms of Functional Dyspepsia are upper abdominal pain that is exaggerated by ingestion of a meal, and delayed gastric emptying. The etiology of these symptoms is not known, which has hampered efforts to develop effective therapeutic agents. A major obstacle in investigation of the etiologies of these symptoms is the lack of availability of tissues from patients and normal subjects to test novel hypothesis and conduct studies at the cellular, molecular and genetic levels. An animal model that concurrently mimics both the symptoms of Functional Dyspepsia is desperately needed to advance the field. The genes are inherited from two parents. However, the DNA requires epigenetic mechanisms to program the expression of individual genes. This programming is accomplished during the fetal and neonatal stages of developments. The information for epigenetic programming is also inherited from the parents. Its goal is to ensure survival of the fetus and the neonate, and normal functioning of the organs in adulthood. However, if the mother or the neonate is exposed to severe psychological or inflammatory stress, the epigenetic mechanisms adapt to ensure immediate survival of the fetus or the neonate under adverse conditions. However, such reprogramming of the genes persists into adulthood and it may result in complex adult diseases, such as diabetes, hypertension and cancer. This phenomenon is called neonatal or fetal programming. Our hypotheses in this proposal are: 1) Colonic inflammation during the vulnerable neonatal stage of development induces the two cardinal symptoms of Functional Dyspepsia, delayed gastric emptying and visceral hypersensitivity to gastric distension in adulthood. 2) The delay in gastric emptying is due to altered gene expression of key cell signaling proteins of the excitation-contraction coupling in gastric smooth muscle cells. 3) Visceral hypersensitivity is due to increase in the excitability of gastric-specific dorsal root ganglionic neurons. 4) The modulation of HPA-axis and epigenetic regulation of specific genes by neonatal programming mediate these effects. We will test these hypotheses in rats using state-of-the-art cellular, molecular and epigenetic approaches. Our findings are expected to yield novel insights into the cellular mechanisms of a major disorder of the gut and identify potential epigenetic and pharmacologic targets for therapeutic agents.
Functional dyspepsia is a major disorder of the gut. It afflicts about 15% to 25% of the U.S. population. The patients with Functional Dyspepsia display symptoms of abdominal pain and delayed gastric emptying. Currently, there is no effective treatment for this disorder. Our findings will elucidate the mechanisms underlying this disorder and identify targets for the development of effective therapeutic agents.
