Nonalcoholic fatty liver disease (NAFLD)--is it a new marker of hyporesponsiveness to recombinant human erythropoietin in patients that are on chronic hemodialysis?

Anemia is a major consequence of chronic kidney disease (CKD) that develops early in the course of illness and affects most patients who exhibit some degree of reduced renal function. Erythropoietin (EPO) deficiency is considered the most important cause of anemia in CKD. Renal anemia has serious clinical consequence. In addition to reducing patient physical capacity and quality of life, anemia induces adaptive cardiovascular mechanisms that increase the risk of cardiovascular disease and death. Thus, treatment of anemia in CKD is very important. While EPO is effective in correcting anemia in most cases, up to 10% of patients however, have an inadequate response to therapy. The two most common and important reasons why patients become relatively unresponsive to EPO therapy are the development of true iron deficiency and the onset of an inflammatory state that impairs the response to EPO. Indeed, the role of inflammation and pro-inflammatory cytokines in resistance to EPO therapy is gaining increasing recognition. On the other hand, the main organ for C-reactive protein (CRP) synthesis is the liver and it is well known that the synthesis of an acute-phase proteins by the liver is up regulated by inflammation. The main consequence of nonalcoholic fatty liver disease (NAFLD) is sub-chronic liver inflammation that leads and contributes to dyslipidemia, inflammation, enhanced oxidative stress and endothelial dysfunction. Considering the recent data about high prevalence of NAFLD in CKD patients, probably due to shared metabolic risk factors, we hypothesized that end-stage renal disease (ESRD) patients with NAFLD will need a much higher dose of EPO to achieve the target hemoglobin levels in comparison with ESRD patients without NAFLD. The possible underlying mechanism is sub-chronic liver inflammation in NAFLD patients that leads and contributes to poor response to EPO. Therefore, we believe that NAFLD could be a new clinical marker of poor response to EPO therapy in ESRD patients. Optimizing response to EPO therapy is important for both patient outcomes and the cost of treatment, and require consideration of a growing number of factors. Detection of NAFLD by some of non-invasive methods in ESRD patients could identify responsiveness and resistance to EPO therapy. Furthermore, we propose that all the patients who undergo dialysis treatment should be screened for NAFLD in order to identify the patients that will have a poor response to EPO therapy. The work could help to determine whether we have a new marker of poor EPO response in ESRD patients.