Macrosteatosis Research Articles

Multi-omics analysis reveals a crosstalk between ferroptosis and peroxisomes on steatotic graft failure after liver transplantation.

To identify the mechanism underlying macrosteatosis (MaS)-related graft failure (GF) in liver transplantation (LT) by multi-omics network analysis. The transcriptome and metabolome were assayed in graft and recipient plasma in discovery (n=68) and validation (n=89) cohorts. Differentially expressed molecules were identified by MaS and GF status. Transcriptional regulatory networks were generated to explore the mechanism for MaS-related inferior post-transplant prognosis. The differentially expressed molecules associated with MaS and GF were enriched in ferroptosis and peroxisome-related pathways. Core features of MaS-related GF were presented on decreased transferrin and impaired anti-oxidative capacity dependent upon dysregulation of transcription factors hepatocytenuclear factor 4A (HNF4A) and hypoxia-inducible factor 1A (HIF1A). Furthermore, miR-362-3p and miR-299-5p inhibited transferrin and HIF1A expression, respectively. Lower M2 macrophages but higher memory CD4 T cells were observed in MaS-related GF cases. These results were validated in clinical specimens and cellular models. Systemic analysis of multi-omics data depicted a panorama of biological pathways deregulated in MaS-related GF. Transcriptional regulatory networks centered on transferrin and anti-oxidant responses were associated with poor MaS graft quality, qualifying as potential targets to improve prognosis of patients after LT.

Point-of-care device for the noninvasive assessment of hepatic macrosteatosis in liver donors

BackgroundQuantification of macrosteatosis (MS) in the liver is important given that it has shown to directly correlate with adverse post-liver transplant (LT) outcomes. With advances in medical technology and an implicit understanding of pathology, noninvasive methods of quantitatively assessing MS are in various stages of development. Each of these methods is based on the physical principles of differences between a fat-laden hepatocyte and a normal one. MethodsIn this regard, after a proof-of-concept study on a prototype for a simple, real-time, handheld device using the principle of diffuse reflectance spectroscopy, this study presents an upgraded point-of-care (POC) device for the noninvasive assessment of hepatic MS in liver donors. ResultsThe device was validated on cohort of donor livers and showed a sensitivity (0.0021 V/% fat) and highly correlated (r = 0.9868, P < .0001) with gold-standard liver biopsy. Results showed that this upgraded POC device provides a reliable method for the noninvasive assessment of hepatic MS, which is crucial for selecting suitable donor livers for LT. ConclusionThe device has the potential to be an invaluable apparatus at the hands of the organ-retrieving surgeon. It is noninvasive, portable (handheld), and economic; provides real-time readings of the percentage of MS; and can be efficaciously handled by any member of the organ-retrieving team.

Protective impacts of Artemisia annua against hepatic toxicity induced by gentamicin.

The current study aimed to investigate the ameliorative effects of Artemisia annua (RA) extract on hepatic toxicity induced by gentamicin injection mice. Sixteen mice were divided into four groups; the control group received saline, the second group received 1% A. annua (RA) extract, third group injected 80mg/kg gentamicin (GEN) intraperitoneally. The protective group treated with a combination of GEN and A. annua. All mice were treated for consecutive 15days. Results confirmed that hepatic biomarkers (GPT, GCT, GOT, IL-6 and IL-1β), all were altered after gentamycin injection. The histological analysis confirmed that gentamycin injected mice showed portal vein congestion, micro and macro steatosis, and nuclear pyknosis of hepatocytes. The protective group showed intact central vein with less microsteatosis of some hepatocytes. Immunochemistry analysis confirmed that the immunoreactivity of COX-2 gene showed negative impact in examined groups. Unlike, NF-κB gene exhibited diffuse positive expression in the gentamicin group. TGF-β1 immunoreactivity was mild positive in control and highly upregulated in gentamicin treated mice, all were normalized after RA administration. In conclusion, RA showed a beneficial impact against gentamycin induced hepatic toxicity at cellular and biochemical levels by regulating proteins and inflammatory markers associated with liver activity.

The effect of Pauttika honey and Orlistat on Histological Evaluations of Liver, Kidney and Adipose tissue in high-fat diet-induced Obesity in Charles Foster male rats

Background: Honey's weight-reducing, hypoglycemic, hypolipidemic, and hepatoprotective properties have been demonstrated. Orlistat, a FDA-approved medicine for obesity control, have adverse effects. Honey is a rich source of nutrients with antiobesity (Medohara) and sacrificant (lekhan) qualities, which help to reduce Pitta, Kapha, and Medas; is suggested in diabetic control. In this study, Pauttika honey is studied against biochemical markers and histological manifestations in visceral organs of high-fat diet-induced obese Charles Foster rats. No research was identified on the effect of Pauttika honey (a specific kind of honey described in Ayurveda) on obese rats' liver, kidney, and adipose tissues. An article on the biochemical analysis of this honey (new and old ) has been already published. Objective: Evaluate the effects of Pauttika honey and Orlistat on high-fat diet-induced fatty changes in obese Charles Foster rats. Methods: This study examines male Charles Foster rat histopathological alterations. 24 male Charles Foster rats with a mean weight of 181±15gm were divided into four groups of six. High-fat diets (HFD) for 8 weeks caused obesity in three groups. After that, Pauttika honey mixed with equal amounts of water (Madudaka) and Orlistat were given to two groups for 6 weeks. The HFD was maintained throughout the experiment, except in the NC group, which ate standard chow. On the last day of the 14th week, the animals were sacrificed and the Liver, kidney, heart, spleen, and lungs were weighed. The liver, kidney, and adipose tissues were preserved in 10% formalin for histopathology. Results: Rats’ relative organ weight (ROW) showed no significant alterations. Histology of liver tissues showed micro and macro steatosis and ballooning degeneration in the HFD group, while Pauttika honey and orlistat both showed improvement in fatty changes but it was better in the Pauttika group. Kidney and adipose tissues showed no morphological or structural abnormalities. Conclusion: This study shows that Pauttika honey mixed with water (Madudaka) protects the livers of obese rats. Histology suggests Pauttika honey is efficacious and safer than Orlistat for HFD-induced obesity.

Graft-to-recipient weight ratio exerts nonlinear effects on prognosis by interacting with donor liver macrosteatosis.

To investigate the interactions between the graft-to-recipient weight ratio (GWRWR) and other risk factors responsible for inferior allograft outcomes. A total of 362 patients who received liver transplantation (LT) were enrolled. Indicators such as graft/recipient weight and other prognostic factors were collected. Comparisons of indicators and survival analysis were performed in groups categorized by the GWRWR. Interactions of large-for-size grafts (LFSGs) with graft macrosteatosis (MaS) were evaluated in terms of relative excess risk caused by interaction (RERI) and attributable proportion (AP). Cytoscape visualized the role of LFSGs in the risk profile for poor prognosis. Based on the GWRWR, LT cases can be categorized into three subgroups, standard (1%-2.5%), optimal (2.5%-3.0%), and inferior prognosis (>3.0%). Survival analysis confirmed clear separations in cases categorized by the above-defined limits on the GWRWR (P < 0.05). LFSGs caused inferior prognosis by initiating positive interactions with MaS severity. The GWRWR exerted nonlinear effects on prognosis in deceased donor LT cases. LFSGs (GWRWR > 3.0%) caused inferior outcomes, while grafts sized within (2.5%-3.0%) had optimal post-transplant prognosis. MaS increased the risk of poor prognosis by exerting positive synergistic effects on LFSGs.

Moringa oleifera Improves MAFLD by Inducing Epigenetic Modifications.

Background and aims. Metabolic Associated Fatty Liver Disease (MAFLD) encompasses a spectrum of diseases from simple steatosis to nonalcoholic steatohepatitis (NASH). Here, we investigated the hepatoprotective role of Moringa oleifera aqueous extract on hepatic miRNAs, genes and protein expression, as well as histological and biochemical parameters in an experimental model of NASH. Methods. Male C57BL/6J mice were fed with a high fat diet (HFD, 60% lipids, 42 gr/L sugar in water) for 16 weeks. Moringa extract was administered via gavage during the final 8 weeks. Insulin Tolerance Test (ITT) and HOMA-IR were calculated. Serum levels of insulin, resistin, leptin and PAI-1 and hepatic expression of miR-21a-5p, miR-103-3p, miR-122-5p, miR-34a-5p and SIRT1, AMPKα and SREBP1c protein were evaluated. Alpha-SMA immunohistochemistry and hematoxylin-eosin, Masson’s trichrome and sirius red staining were made. Hepatic transcriptome was analyzed using microarrays. Results. Animals treated with Moringa extract improved ITT and decreased SREBP1c hepatic protein, while SIRT1 increased. Hepatic expression of miR-21a-5p, miR-103-3p and miR-122-5p, miR34a-5p was downregulated. Hepatic histologic analysis showed in Moringa group (HF + MO) a significant decrease in inflammatory nodules, macro steatosis, fibrosis, collagen and αSMA reactivity. Analysis of hepatic transcriptome showed down expression of mRNAs implicated in DNA response to damage, endoplasmic reticulum stress, lipid biosynthesis and insulin resistance. Moringa reduced insulin resistance, de novo lipogenesis, hepatic inflammation and ER stress. Conclusions. Moringa prevented progression of liver damage in a model of NASH and improved biochemical, histological and hepatic expression of genes and miRNAs implicated in MAFLD/NASH development.

Clear mortality gap caused by graft macrosteatosis in Chinese patients after cadaveric liver transplantation.

Liver transplantation (LT) is one of the most effective surgical treatment for patients with end-stage liver disease. Steatosis is a contributor for inferior graft quality. But its impact and safety on transplantation was less assessed in Chinese patients. Graft steatosis and related information involved in recipients, donors and surgical procedures were retrospectively collected from 239 patients. Donor macrosteatosis (MaS) caused about 2.14 and 2.80 folds of increment on patient and graft mortality. Dose-response analysis revealed prominent risk of grafts on overall patient/organ mortality when MaS content exceeded 10% (P<0.05). Noteworthy, deaths were only observed in MaS group when concurrent with extremely higher post-transplant alanine aminotransferase (ALT, 64%). However, microsteatosis (MiS) grafts didn't affect outcomes after LT. In a cohort of Chinese patients, MaS had comprehensive effects on post-transplant outcomes with relatively lower safety threshold at 10%. Mortality gap caused by MaS grafts was observed in patients with severer ischemia reperfusion injury. Our study revealled the graft MaS affected the post-transplant outcomes in lower risk cutoff in Chinese patients. Further study is worthy to validate these results and investigate inner mechanism under the phenomenon.

Metabonomic Profile of Macrosteatotic Allografts for Orthotopic Liver Transplantation in Patients With Initial Poor Function: Mechanistic Investigation and Prognostic Prediction.

BackgroundOur previous study revealled amplified hazardous effects of macrosteatosis (MaS) on graft failure (GF) in recipients with severe liver damage in short post-operative days, with vague mechanism inside.AimWe aimed to uncover the molecular mechanism of donor MaS on GF, and construct the predictive model to monitor post-transplant prognosis based on “omics” perspective.MethodsUltra-performance liquid chromatography coupled to mass spectrometry metabolomic analysis was performed in allograft tissues from 82 patients with initial poor function (IPF) from multi-liver transplant (LT) centers. Pathway analysis was performed by on-line toolkit Metaboanalyst (v 3.0). Predictive model was constructed based on combinative metabonomic and clinical data extracted by stepwised cox proportional analysis.ResultsPrinciple component analysis (PCA) analysis revealled stratification on metabolic feature in organs classified by MaS status. Differential metabolits both associated with MaS and GF were significantly enriched on pathway of glycerophospholipid metabolism (P < 0.05). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) involved in glycerophospholipid metabolism was significantly decreased in cases with MaS donors and GF (P < 0.05). Better prediction was observed on graft survival by combinative model (area under the curve = 0.91) and confirmed by internal validation.ConclusionMetabonomic features of allografts can be clearly distinguished by MaS status in patients with IPF. Dysfunction on glycerophospholipid metabolism was culprit to link donor MaS and final GF. Decrement on PC and PE exerted the fatal effects of MaS on organ failure. Metabonomic data might help for monitoring long-term graft survival after LT.

Microsteatosis in Livers From Donation After Circulatory Death Donors Is Associated With Inferior Outcomes Following Liver Transplantation.

The acceptable threshold remains unknown for the percentage of macrosteatosis (MaS) and microsteatosis (MiS) to yield optimal outcomes after donation after circulatory death (DCD) liver transplantation (LT). The purpose of this analysis was to determine the impact of donor liver MaS and MiS on DCD LT outcomes. Using the Organ Procurement and Transplantation Network database, we analyzed pretransplant biopsy results from adult, solitary, DCD livers transplanted between January 1, 2006, and December 31, 2017. Kaplan-Meier analysis was used to assess graft and patient survival based on MaS and MiS severity. MiS was divided into the groups MiS ≤10% and >10%. MaS was divided into the groups MaS ≤15% and >15%. Of 7757 recovered DCD livers, 11.4% (n=885) were biopsied and transplanted. Patients who received DCD livers with MaS >15% had significantly worse patient survival (P<0.04), and those with MiS >10% demonstrated inferior graft and patient survival (P<0.02). In multivariate analyses including known risk factors, both MaS >15% and MiS >10% were associated with increased risk of graft failure and patient mortality (P<0.03). Recipient and donor age >60years were also associated with increased risk of graft failure and patient death. This analysis demonstrates that MaS >15% and MiS >10% are additional risk factors for graft loss and patient mortality in DCD LT.

A pilot study of ex-vivo MRI-PDFF of donor livers for assessment of steatosis and predicting early graft dysfunction.

BackgroundThe utility of ex vivo Magnetic resonance imaging proton density fat fraction (MRI-PDFF) in donor liver fat quantification is unknown.PurposeTo evaluate the diagnostic accuracy and utility in predicting early allograft dysfunction (EAD) of ex vivo MRI-PDFF measurement of fat in deceased donor livers using histology as the gold standard.MethodsWe performed Ex vivo, 1.5 Tesla MRI-PDFF on 33 human deceased donor livers before implantation, enroute to the operating room. After the exclusion of 4 images (technical errors), 29 MRI images were evaluable. Histology was evaluable in 27 of 29 patients. EAD was defined as a peak value of aminotransferase >2000 IU/mL during the first week or an INR of ≥1.6 or bilirubin ≥10 mg/dL at day 7.ResultsMRI-PDFF values showed a strong positive correlation (Pearson’s correlation coefficient) when histology (macro-steatosis) was included (r = 0.78, 95% confidence interval 0.57‐0.89, p<0.0001). The correlation appeared much stronger when macro plus micro-steatosis were included (r = 0.87, 95% confidence interval 0.72‐0.94, p<0.0001). EAD was noted in 7(25%) subjects. AUC (Area Under the Curve) for macro steatosis (histology) predicted EAD in 73% (95% CI: 48–99), micro plus macro steatosis in 76% (95% CI: 49–100). AUC for PDFF values predicted EAD in 67(35–98). Comparison of the ROC curves in a multivariate model revealed, adding MRI PDFF values to macro steatosis increased the ability of the model in predicting EAD (AUC: 79%, 95% CI: 59–99), and addition of macro plus micro steatosis based on histology predicted EAD even better (AUC: 90%: 79–100, P = 0.054).ConclusionIn this pilot study, MRI-PDFF imaging showed potential utility in quantifying hepatic steatosis ex-vivo donor liver evaluation and the ability to predict EAD related to severe allograft steatosis in the recipient.

Higher thresholds for the utilization of steatotic allografts in liver transplantation: Analysis froma U.S. national database.

BackgroundHistorically, liver allografts with >30% macrosteatosis (MaS) on donor biopsy have been associated with early allograft dysfunction and worse graft survival; however, successful outcomes have been reported in small cohorts. This study proposes an elevated MaS threshold for organ utilization without detriment to graft survival.MethodsThe UNOS Standard Transplant Analysis and Research database was evaluated for transplants between 2006–2015. Graft survival up to 1-year was evaluated by Kaplan-Meier (KM) survival analyses, and by univariate and multivariable logistic regression analyses, including donor and recipient characteristics. Odds ratios (OR) with 95% confidence intervals (CI) for risk of graft loss are reported.ResultsThirty-day risk of graft loss was increased with MaS as low as 10–19% (OR [95% CI] 1.301 [1.055–1.605], p<0.0001) and peaked with MaS 50–59% (2.921 [1.672–5.103]). At 1-year, risk of graft loss remained elevated with MaS 40–49% (1.465 [1.002–2.142]) and MaS 50–59% (1.978 [1.281–3.056], p = 0.0224). Multivariable models were created for Lower and Higher MELD recipients and MaS cutoffs were established. In Lower MELD recipients, organs with ≥50% MaS had increased risk of graft loss at 30 days (2.451 [1.541–3.897], p = 0.0008) and 1-year post-transplant (1.720 [1.224–2.418], p = 0.0125). Higher MELD recipients had increased risk of graft loss at 30 days with allografts showing MaS ≥40% (4.204 [1.440–5.076], p = 0.0016). At 1-year the risk remained increased, but MaS was not significant predictor of graft loss.048 [1.131–3.710], p = 0.0616). In both MELD cohorts, organs with MaS levels below threshold had similar survival to those transplanted without a donor biopsy.ConclusionsIn conjunction with recipient selection, organs with MaS up to 50% may be safely used without detriment to outcomes.

Effect of Donor Hepatic Steatosis on Ischemia Reperfusion Injury in Liver Transplant Recipient

Ischemia reperfusion injury (IRI) is an important complication of liver transplant (LT). The donor risk index, which does not incorporate steatosis, includes several variables known to impact on allograft survival. The purpose of this study was to report on donor liver allograft steatosis and its association with severity of IRI. The aim of this study was to determine the effect of type and grade of donor liver steatosis on the occurrence and severity of IRI in LT recipients. This was an observational study conducted at a single center over a period of 37 months from July 2013 to August 2016. Liver biopsy was performed twice, initially at the time of procurement before graft perfusion for steatosis assessment. Steatosis was classified as microsteatosis (MiS) or macrosteatosis (MaS) with mild, moderate, or severe grade. Second biopsy for IRI assessment was taken before skin closure in death donor LT (DDLT) and at the time of transaminitis in postoperative period (<72hrs) in living donor LT (LDLT). IRI was graded as per neutrophil infiltrate, apoptosis, and hepatocyte cell dropout. Prevalence of IRI and association steatosis was studied along with other factors. Among 53 subjects, 35 were DDLTs and 18 were LDLTs. All live donor grafts were restricted to <15% MaS and the deceased liver grafts had different type and degree of steatosis. In DDLTs, the association between occurrence of IRI and MaS was not statistically significant (P= 0.201). In DDLTs, the mild steatosis was not significantly associated with IRI. Death donor and ischemic time were significantly associated with IRI. Child's stage and MELD scores, gender, and age were not associated with risk of IRI. Severity of IRI is significantly associated with 3-month mortality (P= 0.001). In patients with mild steatosis, IRI does not correlate with steatosis. However, more patients with moderate and severe steatosis are needed to define the relationship of the two in this group of patients.

Mapping the triglyceride distribution in NAFLD human liver by MALDI imaging mass spectrometry reveals molecular differences in micro and macro steatosis.

Hepatic lipid accumulation, mainly in the form of triglycerides (TGs), is the hallmark of non-alcoholic fatty liver disease (NAFLD). To date, the spatial distribution of individual lipids in NAFLD-affected livers is not well characterized. This study aims to map the triglyceride distribution in normal human liver samples and livers with NAFLD and cirrhosis with imaging mass spectrometry (MALDI IMS). Specifically, whether individual triglyceride species differing by fatty acid chain length and degree of saturation correlate with the histopathological features of NAFLD as identified with classical H&E. Using a recently reported sodium-doped gold-assisted laser desorption/ionization IMS sample preparation, 20 human liver samples (five normal livers, five samples with simple steatosis, five samples with steatohepatitis, and five samples with cirrhosis) were analyzed at 10-μm lateral resolution. A total of 24 individual lipid species, primarily neutral lipids, were identified (22 TGs and two phospholipids). In samples with a low level of steatosis, TGs accumulated around the pericentral zone. In all samples, TGs with different degrees of side-chain saturation and side-chain length demonstrated differential distribution. Furthermore, hepatocytes containing macro lipid droplets were highly enriched in fully saturated triglycerides. This enrichment was also observed in areas of hepatocyte ballooning in samples with steatohepatitis and cirrhosis. In conclusion, macro lipid droplets in NAFLD are enriched in fully saturated triglycerides, indicating a possible increase in de novo lipogenesis that leads to steatohepatitis and cirrhosis.

Evaluation of a micro-spectrometer for the real-time assessment of liver graft with mild-to-moderate macrosteatosis: A proof of concept study

Liver macrosteatosis (MS) is a major predictor of graft dysfunction after transplantation. However, frozen section techniques to quantify steatosis are often unavailable in the context of procurements, and the findings of preoperative imaging techniques correlate poorly with those of permanent sections, so that the surgeon is ultimately responsible for the decision. Our aim was to assess the accuracy of a non-invasive pocket-sized micro-spectrometer (PSM) for the real-time estimation of MS. We prospectively evaluated a commercial PSM by scanning the liver capsule. A double pathological quantification of MS was performed on permanent sections. Initial calibration (training cohort) was performed on 35 livers (MS ≤60%) and an algorithm was created to correlate the estimated (PSM) and known (pathological) MS values. A second assessment (validation cohort) was then performed on 154 grafts. Our algorithm achieved a coefficient of determination R2 = 0.81. Its validation on the second cohort demonstrated a Lin's concordance coefficient of 0.78. Accuracy reached 0.91%, with reproducibility of 86.3%. The sensitivity, specificity, positive and negative predictive values for MS ≥30% were 66.7%, 100%, 100% and 98%, respectively. The PSM could predict the absence (<30%)/presence (≥30%) of MS with a kappa coefficient of 0.79. Neither graft weight nor height, donor body mass index nor the CT-scan liver-to-spleen attenuation ratio could accurately predict MS. We demonstrated that a PSM can reliably and reproducibly assess mild-to-moderate MS. Its low cost and the immediacy of results may offer considerable added-value decision support for surgeons. This tool could avoid the detrimental and prolonged ischaemia caused by the pathological examination of (potentially) marginal grafts. This device now needs to be assessed in the context of a large-scale multicentre study. Macro-vacuolar liver steatosis is a major prognostic factor for outcomes after liver transplantation. However, it is often difficult for logistical reasons to get this estimation during procurement. Therefore, we developed an algorithm for a commercial, portable and affordable spectrometer to accurately estimate this content in a real-time fashion. This device could be of great interest for clinical decision-making to accept or discard a potential human liver graft.

Impact of Graft Steatosis on Postoperative Complications after Liver Transplantation.

Background Steatotic grafts are more susceptible to ischemia-reperfusion injury than are normal grafts. Therefore, using steatotic grafts for liver transplantation (LT) is associated with high primary dysfunction and decreased survival rates. The aim of this study is to evaluate the impact of graft steatosis on post LT outcomes. Methods A retrospective cohort analysis of 271 LT recipients from 2005 to 2016 was performed and patients were classified based on two types of steatosis, macrosteatosis (MaS), and microsteatosis (MiS). Each category was subdivided into three groups according to the degree of steatosis: no (< 5%), mild (≥5 to < 30%), and moderate (≥30 to ≤60%). The primary hospital stays and 6-month postoperative complications were analyzed by the Clavien–Dindo classification system. Additionally, patient and graft survivals were studied. Results Significant differences were observed in grade III MaS ( p -value = 0.019) and grade V MiS ( p -value = 0.020). A high trend of early graft dysfunction was found in the moderate MaS and MiS groups; however, they were not statistically significant ( p -value = 0.199 and 0.282, respectively). Interestingly, the acute cellular rejection (ACR) rate was found to be inversely proportional to the degree of steatosis in both categories but it did not reach a significant level ( p -value = 0.161 and 0.111, respectively). Conclusion Excellent post LT long-term outcomes using grafts with mild and moderate steatosis were determined. Further studies are needed to evaluate the newly proposed relationship between ACR and steatosis.

Suitability of livers for transplantation when treated by normothermic machine perfusion.

Many factors may compromise the functional recovery of a harvested potential liver for engraftment. Normothermic machine perfusion (NMP) can revive hepatic metabolism ex vivo enabling subsequent transplantation. In this study, we evaluated the recovery of 11 discarded livers' function utilizing NMP. Eleven consecutive discarded livers underwent NMP for 6hours. Liver function recovery was defined by lactate levels of ≤3mmol/L and continuous bile production. Ten of 11 livers perfused were fatty. The median percentage of macrosteatosis (MaS) and microsteatosis (MiS) was 40% (10%-90%) and 40% (20%-50%), respectively, based on a review of paraffin-embedded sections of preperfusion biopsies. A discarded "amyloid" liver from an HIV-positive donor was also studied. Recovery of liver function was observed in 4 livers, including that with the amyloid deposition. These livers sustained shorter cold ischemia times and seemed to have increased portal and arterial blood flow. No significant change in MiS or MaS was observed before and after perfusion. Our results suggest that some discarded grafts might have been salvaged for transplantation. Further studies utilizing NMP with subsequent transplantation would validate this strategy.

Resolution of donor non-alcoholic fatty liver disease following liver transplantation.

Transplant surgeons conventionally select against livers displaying high degrees (>30%) of macrosteatosis (MaS), out of concern for primary non-function or severe graft dysfunction. As such, there is relatively limited experience with such livers, and the natural history remains incompletely characterized. We present our experience of transplanted livers with high degrees of MaS and microsteatosis (MiS), with a focus on the histopathologic and clinical outcomes. Twenty-nine cases were identified with liver biopsies available from both the donor and the corresponding liver transplant recipient. Donor liver biopsies displayed either MaS or MiS ≥15%, while all recipients received postoperative liver biopsies for cause. The mean donor MaS and MiS were 15.6% (range 0%-60%) and 41.3% (7.5%-97.5%), respectively. MaS decreased significantly from donor (M=15.6%) to recipient postoperative biopsies (M=0.86%), P<.001. Similarly, MiS decreased significantly from donor biopsies (M=41.3%) to recipient postoperative biopsies (M=1.8%), P<.001. At a median of 68days postoperatively (range 4-384), full resolution of MaS and MiS was observed in 27 of 29 recipients. High degrees of MaS and MiS in donor livers resolve in recipients following liver transplantation. Further insight into the mechanisms responsible for treating fatty liver diseases could translate into therapeutic targets.

Microsteatosis may not interact with macrosteatosis in living donor liver transplantation

The insignificance of pure microsteatosis (MiS) was reported in living donor liver transplantation (LDLT). However, since steatosis is mostly found in a mixed form of microsteatosis (MiS) and macrosteatosis (MaS), we aimed to determine the importance of MiS mixed with MaS in LDLT. Donor matching and recipient matching were independently performed with unfixed matching ratios. In donor matching, 51 donors with high (⩾30%) MiS mixed with MaS (H-MiS) were matched with 160 donors with low (⩽10%) MiS mixed with MaS (L-MiS), based on MaS degree, remnant liver volume, and others. In recipient matching, 50 recipients who received H-MiS grafts were matched with 176 recipients who received L-MiS grafts, based on MaS degree, graft volume, MELD score, and others. The median MiS degree was 10% (range 0%-10%) vs. 35% (range 30%-80%) in L-MiS livers vs. H-MiS livers after both matching. L-MiS and H-MiS donors were not significantly different regarding postoperative biochemical liver function (e.g. peak AST 232 vs. 246 IU/L, p=0.931). L-MiS and H-MiS recipients were not significantly different regarding 2-week graft regeneration (51% for both) and 5-year survival (HR 0.87, 95% CI 0.43-1.76, p=0.699). Post-transplant donor/recipient complication rates were not significantly different, either. There were no evidences of a significant impact of MiS mixed with MaS on post-LDLT outcomes. The results suggest less importance of MiS, and further indicate that there is no interaction between MiS and MaS. Thus, the risk of steatosis may be determined by the relative composition of MiS and MaS, rather than the total quantitative degree.

Liver Regeneration After Ischemia Reperfusion Injury in High-Fat-Diet Induced Hepatic Microsteatosis and Macrosteatosis.

Fatty livers have low tolerance to IRI and high risks of organ failure after transplantation. Impaired liver regeneration, often attributed to fatty livers, is a frequent feature in acute liver failure. The present study unveils mechanisms of hepatic regeneration in clinically relevant models of lean and steatotic hepatic IRI. Methods and Results: C57BL6 mice were fed with standard or high-fat (HF; 60% of total kilocalories) diets for up to 8 weeks. Mice fed with a standard diet had virtually no liver fat inclusions, whereas HF-diet-fed mice with about 29-33g and 40-45g of body weight were characterized by prevalence of liver microsteatosis (MiS) and macrosteatosis (MaS), respectively (assessed by H&E, Oil-red O staining, and triglyceride levels). Mice were submitted to partial warm ischemia for 60- or 90-min ischemia followed by reperfusion. In 60-min IRI, all lean, MiS, and MaS mice survived post-reperfusion. MaS mice had significantly higher serum AST (11632±3238 vs. 2123±1424 vs. 380±269) levels (U/L) compared with MiS (p<0.05) and lean (p<0.05) mice, respectively, at 24h after IRI. Cyclin D1 is one of the key regulatory proteins of the cell cycle; its expression is required for transition from the G1 into the S phase. The relatively well-preserved lean livers showed significantly increased Cyclin D1 expression (1.18±0.26 vs. 0.24±0.13 vs. 0.04±0.01), but reduced PCNA levels (0.03±0.003 vs. 0.86±0.14 vs. 0.29±0.03), compared with MiSand MaS livers (respectively, p<0.05) at 48h post-IRI. In 90-min IRI, all lean and MiS mice survived surgery, despite significant liver damage, while only 40% of the MaS mice were alive after the first two postoperative days. Here, lean mice showed significantly higher expression levels of both Cyclin D1 (0.47±0.01vs. 0.31±0.02 vs. 0.10±0.02) and PCNA (0.40±0.05 vs. 0.23±0.05 vs. 0.13±0.04), compared with MiS and MaS mice (respectively, p<0.05) at 48h post-IRI. PCNA protein expression levels correlated with the hepatocyte proliferation index in all evaluated tissues. Conclusion: This thorough study demonstrates distinct expression patterns of cell-cycle regulators in macrosteatotic, microsteatotic and lean livers after IRI. Moreover, it suggests that while Cyclin D1 levels reflect the capability of livers to regenerate post-reperfusion, PCNA levels represent their regenerative activity.

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

A safe use of intermittent hepatic inflow occlusion (IHIO) has been reported for living donor hepatectomy. However, it remains unclear whether the maneuver is safe in steatotic donors. In addition, the respective importance of macrosteatosis (MaS) and microsteatosis (MiS) is an important issue. Thus, we compared MiS and MaS with respect to the tolerance of hepatic ischemia/reperfusion (IR) injury induced by IHIO. One hundred forty-four donors who underwent a right hepatectomy were grouped according to the presence of MaS and MiS: a non-MaS group (n = 68) versus an MaS group (n = 76) and a non-MiS group (n = 51) versus an MiS group (n = 93). The coefficients of the regression lines between the cumulative IHIO time and the peak postoperative transaminase concentrations were used as surrogate parameters indicating the tolerance of hepatic IR injury. The coefficients were significantly greater for the MaS group versus the non-MaS group (4.12 ± 0.59 versus 2.22 ± 0.46 for alanine aminotransferase, P = 0.01). Conversely, the MiS and non-MiS groups were comparable. A subgroup analysis of donors who underwent IHIO for >30 minutes showed that MaS significantly increased the transaminase concentrations, whereas MiS had no impact. Also, IHIO for >30 minutes significantly increased the biliary complication rate for MaS donors (12.1% for ≤ 30 minutes versus 32.6% for >30 minutes, P = 0.04), whereas MiS donors were not affected. In conclusion, the tolerance of hepatic IR injury might differ between MaS livers and MiS livers. It would be rational to assign more clinical importance to MaS versus MiS. We further recommend limiting the cumulative IHIO time to 30 minutes or less for MaS donors undergoing right hepatectomy.