e., glycogen and adenosine triphosphate.33 Some protective see more strategies in young animals, such as ischemic preconditioning, were no longer effective in older animals, but protection could be restored by reloading the energy stores with glucose.33 This finding was confirmed in a prospective randomized controlled study that tested the effect of ischemic
preconditioning in patients undergoing liver resection. Patients above the age of 65 years did not benefit from the protective effect of preconditioning.34 Despite the aforementioned limitations, several studies failed to show that advanced age affects the outcome of patients undergoing a variety of surgical procedures35-37 including this website liver surgery.22, 38, 39 Yet, age has to be considered a significant risk factor for major liver resection and partial liver transplantation.1, 40 Many studies have shown that steatosis, particularly severe steatosis, is a significant risk factor for postoperative complications after major liver resection,41-43 and exerts detrimental effects on graft and patient survival after OLT.44-48 In contrast, other studies failed to identify any negative effects.49-53 These discrepancies
have led to many uncertainties in this field. Hepatic steatosis is defined as excessive lipid accumulation that exceeds 5%-10% of the organ weight.43 In clinical practice, microscopic assessment of fat droplets in hepatocytes, mostly on sections stained with hematoxylin and eosin, represents the gold standard by which to characterize hepatic steatosis. Quantitative assessment is recorded as the percent of hepatocytes containing lipid droplets (mild steatosis: <30%; moderate: 30%-60%; and severe >60%), whereas qualitative assessment
takes into account the size of the droplets in hepatocytes.54, 55 If the lipid droplets displace the nucleus, it is considered macrosteatosis, otherwise the term microsteatosis is used. Many pitfalls have been demonstrated with this approach, including errors due to liver sampling,56 the inhomogeneous Thiamet G distribution of lipids throughout the liver,57 and fixation and staining of liver sections.45, 58 In addition, we recently showed poor agreement among expert pathologists from different institutions in assessing steatosis, both quantitatively and qualitatively, in the same liver sections.59 For example, one pathologist diagnosed 22% of patients with marked (≥30%) steatosis, whereas another recorded an incidence of 46%. Also, significant disagreement was documented regarding many features of steatohepatitis.59 The actual types and contents of fat in the liver are most likely more relevant to predict outcome after surgery and transplantation than the amount.54, 60, 61 The distinction between microsteatosis versus macrosteatosis might be artificial, because continuity exists between both forms of fat.