NASH Fitness Intervention in Thrombosis Trial (NASHFit)

Overview

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in the United States. The most advanced forms of NAFLD are associated with increased liver-related mortality and lower overall survival. The current standard of care for NAFLD is lifestyle changes through diet and exercise. The human genome and regulation of gene expression is influenced by physical activity. NAFLD is a prothrombotic state with derangements in all three phases of hemostasis leading to clinically important clotting events. Exercise can improve coagulation in healthy persons. In this proposal, we seek to begin a line of work to answer the question "Can lifestyle changes effectively mitigate the increased risk of clotting in patients with NAFLD?" focusing initially on the at-risk population genetically susceptible to advanced disease.

Often comorbid with obesity, nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in the United States affecting 75-100 million adults, of which 15-20 million have the more severe variant nonalcoholic steatohepatitis (NASH). Conservative estimates project a doubling in NASH by 2025.The most advanced forms of NAFLD are associated with increased liver-related mortality and lower overall survival. The most effective treatment for NAFLD remains adopting healthy dietary and exercise patterns, however NAFLD patients are among the least physically active individuals. Predicting exercise behavior on an individual level is highly complex due to differing motivation, physiologic response to and subjective experience of exercise as well as emerging genetic evidence. The human genome and regulation of gene expression is influenced by physical activity. Patatin like phospholipase-3 (PNPLA3) rs738409 polymorphism (GG, GC and CC genotypes) plays a crucial role in the development of NAFLD. The GG genotype is both associated with advanced NAFLD, and predicts response to physical activity. Patients with NASH have extensive extrahepatic disease and are hypercoagulable. NASH is a prothrombotic state with fibrinolytic dysfunction through elevated plasminogen activator inhibitor (PAI-1), an independent risk factor for venous thromboembolism (VTE). Consequently, patients with NASH are predisposed to VTE; the risk of portal vein thrombosis (PVT) in NASH is 210% greater than in other liver disease. NASH patients are also at increased risk for pulmonary embolism (PE) and deep vein thrombosis (DVT).The most advanced forms of NASH have the greatest thrombotic risk. While studies observe that change in diet, weight and physical activity patterns improve NASH, it is not clear whether these lifestyle changes also reduce the elevated clot risk, however, moderate-intensity exercise leads to improved fibrinolysis in healthy persons.The NASHFit study is being done to find out if exercise is beneficial in decreasing the risk of clotting problems in patients with NASH. Exercise has been shown to decrease markers of clotting in healthy individuals as well as in those with cardiovascular disease.