Effect of pure microsteatosis on transplant outcomes after living donor liver transplantation: A matched case-control study

Abstract

Liver steatosis mostly exists in a mixed form of macrosteatosis (MaS) and microsteatosis (MiS). This coexistence is responsible for previous conflicting results regarding the importance of MiS in liver transplantation. We aimed to evaluate the independent effect of MiS on posttransplant outcomes with the exclusion of the confounding effect of MaS. Seventy-one living donors who had pure MiS (defined as an MiS degree > 5% without MaS) were matched 1:1 with control donors, and 66 recipients who received pure MiS grafts were matched 1:1 with control recipients on the basis of propensity scores. Matched variables included the donor age, remnant liver volume, cold ischemia time, graft-to-recipient weight ratio and Model for End-Stage Liver Disease score. The degree of pure MiS ranged from 5% to 50%. Donors in the control and pure MiS groups were comparable with respect to peak postoperative transaminase concentrations [alanine aminotransferase (ALT): 194 versus 176 IU/L, P 5 0.61] and postoperative complications. Recipients in the control and pure MiS groups were comparable with respect to recipient (P 5 0.15) and graft survival rates (P 5 0.56) as well as peak postoperative transaminase concentrations (ALT: 266 versus 281 IU/L, P 5 0.88), and graft regeneration rates at 2 weeks (61% versus 59%, P 5 0.73). The 2 groups were also comparable with respect to major complications, primary graft dysfunction/nonfunction, intensive care unit/hospital stays, and metabolic diseases. In conclusion, MiS alone does not seem to impair the posttransplant outcomes of living donors and their recipients. The interaction between MiS and MaS, and the effect of a greater degree of MiS are the next important topics to be further evaluated in the mixed steatosis population. Liver

Comparison of the tolerance of hepatic ischemia/reperfusion injury in living donors: Macrosteatosis versus microsteatosis

“…Nonetheless, the present study revealed that MiS was not associated with the tolerance of hepatic IR injury or clinical courses after IHIO, and this strongly suggested an insignificant role for MiS. These findings were reinforced by a subgroup analysis comparing normal and pure MiS donors in agreement with a previous study . Furthermore, a recent study of rats suggesting a possible mechanism for an insignificant effect of MiS through a comparison of MaS‐dominant livers (58% MaS and 27% MiS) and MiS‐dominant livers (70% MiS and 17% MaS) supports our results.…”

“…These findings were reinforced by a subgroup analysis comparing normal and pure MiS donors in agreement with a previous study. 27 Furthermore, a recent study of rats 20 suggesting a possible mechanism for an insignificant effect of MiS through a comparison of MaS-dominant livers (58% MaS and 27% MiS) and MiS-dominant livers (70% MiS and 17% MaS) supports our results. The study clearly demonstrated that the microcirculation of MiS livers was well maintained after IR injury, whereas that of MaS livers was significantly impaired.…”

The impact of diet‐induced hepatic steatosis in a murine model of hepatic ischemia/reperfusion injury

“…Some data suggest that macrovesicular steatosis, defined as the presence of a lipid droplet leading to displacement of the nucleus, is generally associated with poor outcomes and to be more injurious to the liver. However, microvesicular steatosis, defined as the presence of multiple lipid droplets without displacement of the nucleus, is thought to result in less liver injury during ischemia/reperfusion (I/R) . The factors that drive these 2 types of steatosis are poorly understood, and the concept that microvesicular steatosis is benign has not been examined in detail.…”

“…However, microvesicular steatosis, defined as the presence of multiple lipid droplets without displacement of the nucleus, is thought to result in less liver injury during ischemia/reperfusion (I/R). (8,17,23,25) The factors that drive these 2 types of steatosis are poorly understood, and the concept that microvesicular steatosis is benign has not been examined in detail.…”

Macrosteatotic and nonmacrosteatotic grafts respond differently to intermittent hepatic inflow occlusion: Comparison of recipient survival

“…More recently, a randomized trial of living donors and their recipients corroborated the safe use of IHIO in LDLT . However, the aforementioned studies did not take into account the interaction between IHIO and macrosteatosis (MaS), which is a major risk form of steatosis and alters the response to hepatic ischemia . Also, they only examined whether or not IHIO was used and did not evaluate the effect of the cumulative occlusion time, which affects the degree of IR injury .…”