Development of Kinetic Biomarkers of Liver Fibrosis Measuring NAFLD
Development of Kinetic Biomarkers of Liver Fibrosis Measuring NAFLD
This is a small preliminary study conducted to explore new methods for the potential of
 aiding in diagnosis of liver fibrotic disease as well as predicting disease progression.
 There will be a total of 4 visits spread out over approximately 8 weeks. You will be asked to
 drink "heavy water" during most of that time. "Heavy Water" also known as deuterated water,
 is physically and chemically very similar to ordinary drinking water. It tastes and feels
 exactly like regular water. It is odorless and has no known harmful effects at the doses
 given here. Heavy water occurs naturally, and is a minor component of the water we all ingest
 daily.
Management of NASH and NAFLD remain a significant unmet medical challenge that is growing in
 importance as part of the obesity epidemic. Minimally invasive tools for monitoring disease
 progression and evaluating therapeutic interventions in NASH would be extremely valuable.
 Utilizing in vivo heavy water labeling, multiple pathways related to protein metabolism
 (fibrogenesis) and lipid metabolism can be quantified in human subjects. We have recently
 discovered that plasma lumicam synthesis represents a non-invasive kinetic biomarker of
 tissue fibrogenesis in patients with viral hepatitis. In addition, synthesis of fatty acids
 in plasma VLDL-triglycerides provide a window into hepatic lipid metabolism.

 Stable isotopes have a long history as a safe, effective tracer for measuring synthesis of
 molecules in humans (1). Recently, new developments in stable isotope labeling techniques and
 advances in mass spectrometry have made in vivo kinetic measurement of slow metabolic
 processes possible. Through the use of 2H2O as the source of labeling, we and others have
 measured T-cell proliferation (2), mammary epithelial cell proliferation (3), prostate
 epithelial cell proliferation (4), triglyceride synthesis (5) and protein synthesis (6) in
 humans. We have recently evaluated this approach for the measurement of fibrogenesis patients
 with fibrotic liver disease.

 Excess accumulation of collagen in the liver is termed fibrosis. Fibrosis is a common
 pathological feature of several chronic liver diseases (e.g. Hepatitis C, alcoholic liver
 disease, primary biliary sclerosis, drug/toxin induced liver disease, etc.). Currently, the
 standard method for detection of fibrosis is liver biopsy and histochemical analyses of
 tissue collagen content (8, 9). Although effective in diagnosing existing, advanced fibrosis,
 a single biopsy cannot measure current disease activity or predict rate of progression. To
 determine whether disease is progressing using current methods, a second biopsy is required.
 If significant additional collagen has accumulated since the first biopsy, this suggests that
 the disease is progressing. However, this measurement represents the history of the disease,
 not the current disease activity at the time of the second biopsy. There are also significant
 limitations in current methods, since changes in collagen pool size measurable by
 histochemistry cannot measure small changes in collagen content and intra-laboratory
 variability inherent in histochemical assays reduce their sensitivity (10, 11).

 This stable isotope / mass spectrometry based method will be applied here for the
 quantification of fibrogenesis in vivo (from a bone marrow biopsy) and the identification of
 novel biomarkers of fibrogenesis in plasma in patients receiving investigational therapies.

 If successful, this research will identify plasma proteins which can be easily measured by
 tandem mass spectrometry (LC/MS/MS) methods and whose synthesis rate reflects disease
 activity in the heart. Ideally, a set of markers related to NASH/ NAFLD will be developed
 that can detect and differentiate among multiple disease phenotypes, based on the kinetic
 signature measured in a single blood draw from a patient labeled with deuterated water.

 The role of de novo lipogenesis (DNL) has been suggested by several clinical studies
 (Donnelly JCI 2005, Puri Hepatology 2009). DNL contributes significantly to the accumulation
 of lipid in NASH (Donnelly JCI 2005). Moreover DNL is elevated in many other inflammatory
 states and may be a useful marker of hepatic inflammation. DNL as well as hepatic TG assembly
 and cholesterogenesis are easily measured in plasma or dried blood spot samples from patients
 consuming 2H2O, after several days of labeling the plasma DNL reaches a steady state and
 reflects hepatic DNL rates.
Inclusion Criteria:

 1. Adults (≥ 18 years of age)

 2. Adult male and female subjects, all races, ethnic groups, social and economic
 backgrounds and health status who are scheduled to undergo a liver biopsy as part of
 routine medical care will be included in the research.

 3. Willingness to follow-up for 8 weeks

 4. Written inform consent.

 Exclusion Criteria:

 1. Children younger than 18 will be excluded, since growth of liver tissue may confound
 measurements of collagen synthesis and cell proliferation due to normal turnover or
 disease.

 2. The eligibility of patients will be determined by Dr. Rohit Loomba, MD or a referring
 physician at the time the potential subject is recommended to undergo a liver biopsy
 procedure as part of their medical treatment.