Proteomics of Pancreatic Fluid and Urine in Chronic Pancreatitis

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ABSTRACT Chronic pancreatitis (CP) is a progressively debilitating disease for which only moderate to advanced diagnosis is possible. In addition, the evaluation of chronic abdominal pain under the suspicion of CP results in millions of dollars in healthcare costs and lost wages annually. CP is characterized by chronic inflammation and progressive scarring leading to irreversible damage to the pancreas, resulting in loss of exocrine and endocrine function and in some cases pancreas carcinoma. The diagnosis of CP within a "therapeutic window" has remained elusive due to our poor understanding of the disease and scarce morphological changes on imaging studies in early and mild disease. The understanding of CP pathogenesis is paramount in early diagnosis. Furthermore, pathophysiology based therapy focused on inflammation could modify or retard disease progression. The health-related topics that I address in this research proposal are: (1) CP pathogenesis is currently poorly understood and (2) clinical diagnosis of CP detects only moderate to advanced disease. I hypothesize that CP-specific proteins can be identified by comprehensive, quantitative proteomic profiling of pancreatic fluid (PF) and that such perturbations of the pancreatic protein secretome is reflected in excreted urine. In Specific Aim 1 (SA1), I will determine if inflammatory proteins in PF are etiology-specific. Using quantitative mass spectrometry, we will evaluate the PF from 6 different etiologies of advanced CP, plus a non-diseased control group and compare the inflammatory protein profile to generate an inclusion list to be used in Specific Aim 2 (SA2). This list of proteins will be validated in SA2 using two large cohorts (1) non-pancreatic disease and (2) CP with varying degrees of pancreatic deficiency. These results will be important in assessing the value of the proteins discovered in SA1 for diagnostic applications. In Specific Aim 3 (SA3), I will investigate inflammation-related proteins in the urine of CP subjects using directed quantitative mass spectrometry. I hypothesize that proteins discovered in SA1 and validated in SA2 can also be identified in urine in SA3. CP- specific, inflammatory-related proteins identified using the strategy outlined herein will originate from: (1) Pancreatic fluid-a proximal body fluid which is ideal for investigation of physiological pathways of pancreatic dysfunction and (2) Urine-a noninvasively collected fluid that is well-suited for clinical diagnostics. While there are many classes of proteins that can be investigated with proteomics in PF, I chose to focus on inflammatory proteins because characterization of their expression may have both diagnostic and therapeutic implications. In conforming with the mission of the NIDDK, I aim to determine the identity, relative quantity, cellular origin, and molecular function of distinct sets of CP-specific, inflammatory proteins with the long-term goals of (1) understanding the inflammatory protein response of CP with respect to etiology, (2) identifying candidate diagnostic markers, and (3) discovering targets for directed therapy.