Role of monocytes and macrophages in experimental and human acute liver failure

Acute liver failure (ALF) is a devastating clinical syndrome characterised by progressive encephalopathy, coagulopathy, and circulatory dysfunction, which commonly leads to multiorgan failure and death. Central to the pathogenesis of ALF is activation of the immune system with mobilisation of cellular effectors and massive production of cytokines. As key components of the innate immune system, monocytes and macrophages are postulated to play a central role in the initiation, progression and resolution of ALF. ALF in humans follows a rapidly progressive clinical course that poses inherent difficulties in delineating the role of these pivotal immune cells. Therefore, a number of experimental models have been used to study the pathogenesis of ALF. Here we consider the evidence from experimental and human studies of ALF on the role of monocytes and macrophages in acute hepatic injury and the ensuing extrahepatic manifestations, including functional monocyte deactivation and multiple organ failure.

Hepcidin levels in hereditary hyperferritinemia:Insights into the iron-sensing mechanism in hepatocytes

AIM:To study the role of hepcidin in hereditary hyperferritinemia cataract syndrome(HHCS). METHODS:Six patients from two families with HHCS, confirmed by genetic analysis showing A to G mutation at position+40 in the L-ferritin gene,were recruited to undergo serum hepcidin and prohepcidin measurements using radioimmunoassay and enzyme linked immunoassay,respectively,and measurements were compared with levels in serum from 25 healthy volunteers(14 females),mean age 36±11.9 years.RESULTS:The serum hepcidin and prohepcidin levels in patients with HHCS were 19.1±18.6 and 187± 120.9 ng/mL,respectively.Serum ferritin was 1716.3± 376μg/L.Liver biopsy in one patient did not show any evidence of iron overload.Serum hepcidin and prohepcidin values in healthy controls(HCs)were 15.30±15.71 and 236.88±83.68 ng/mL,respectively,while serum ferritin was 110±128.08μg/L.There was no statistical difference in serum hepcidin level between the two cohorts(19.1±18.6 ng/mL vs 15.30±15.71 ng/mL,P= 0.612)using two-tailed t-test. CONCLUSION:Serum hepcidin levels in HHCS patients is similar to that in HCs.Our study suggests that circulating ferritin is not a factor influencing hepcidin synthesis and does not have a role in the iron-sensing mechanism in hepatocytes.

Liver function tests and metabolic-associated fatty liver disease:Changes in upper normal limits,does it really matter?

BACKGROUND Metabolic-associated fatty liver disease(MAFLD)is the commonest cause of abnormal liver function tests(LFTs).Current upper normal of limit(UNL)of LFTs was derived from a“healthy”population,where undiagnosed MAFLD and viral hepatitis might be suspected.AIM To evaluated potential implications of changes in UNL of alanine aminotransferase(ALT)in MAFLD.METHODS We retrospectively assessed consecutive first referrals with a diagnosis of MAFLD from 2010 to 2017.The conventional UNL of ALT was 45 IU/L for men and 34 IU/L for women,while a low UNL of ALT was 30 IU/L for men and 19 IU/L for women.The UNL of aspartate aminotransferase(AST)was 40 IU/L.RESULTS Total 436 patients were enrolled;of these,288 underwent liver biopsy.Setting a lower UNL reduced the percentage of those with significant disease despite normal ALT;specifically,patients with advanced fibrosis(F≥F3)or definite“metabolic-associated steato-hepatitis(MASH)”(NAS≥5)within normal ALT decreased from 10%to 1%and from 28%to 4%respectively.However,the proportion of those with elevated ALT and no evidence of advanced fibrosis or“definite MASH”increased from 39%to 47%and from 3%to 19%.Overall,LFTs performed poorly in distinguishing“definite MASH”from simple steatosis(receiver operating characteristic areas under the curves 0.59 for ALT and 0.55 for AST).CONCLUSION Liver function tests might both under-and overestimate MASH-related liver disease.Reducing the UNL might not be beneficial and imply an increase in healthcare burden.Risk stratification in MAFLD should rely on a combination of risk factors,not on LFTs alone.

Presence of hepcidin-25 in biological fluids: Bile,ascitic and pleural fluids

AIM: To examine body fluids such as ascitic fluid (AF),saliva,bile and pleural effusions for the presence of hepcidin using a novel radioimmunoassay (RIA).METHODS: Serum samples were collected from 25 healthy volunteers (mean age: 36 ± 11.9 years,11 males,14 females).In addition bile was obtained from 12 patients undergoing endoscopic retrograde cholangiopancreatography (mean age: 66.9 ± 16.7 years,M:F = 5:7).Saliva was collected from 17 healthy volunteers (mean age: 35 ± 9.9 years,M:F = 8:9).Pleural and AF were collected from 11 and 16 patients [(mean age: 72 ± 20.5 years,M:F = 7:4) and (mean age: 67.32 ± 15.2 years,M:F = 12:4)],respectively.All biological fluid samples (serum,exudative and transudative fluids) were tested for the presence of hepcidin-25 molecule using RIA.RESULTS: Hepcidin-25 was detected in all biological fluids tested.The mean ± SD hepcidin-25 in serum was 15.68 ± 15.7 ng/mL,bile 7.37 ± 7.4 ng/mL,saliva 3.4 ± 2.8 ng/mL,exudative fluid 65.64 ± 96.82 ng/mL and transudative fluid 14.1 ± 17.8 ng/mL.CONCLUSION: We provide clear evidence that hepcidin-25 is present in bile,saliva,pleural and ascitic fluids.Hepcidin is likely to play a role here in innate immunity.

Granulocyte colony-stimulating factor as a novel adjunct to improve hepatitis B vaccination

Hepatitis B vaccination is successful in 95% of individuals. In the remainder, despite repeated attempts, immunization often remains unsuccessful. 'Non-response' leaves the individual susceptible to infection. Various strategies have been employed to overcome this. These include the use of adjuncts alongside conventional vaccines which activate immune responses. In this case report we demonstrate the successful use of the hematopoietic growth factor Granulocyte colonystimulating factor (G-CSF) as a vaccine adjunct in an individual who had previously failed conventional vaccination three times. The patient tolerated the regimen without any side effects and achieved a hepatitis B surface antibody titer greater than 100 IU/L. Use of G-CSF as a vaccine adjunct for hepatitis B has not previously been reported and the outcome in this case suggests that the use of G-CSF in this context warrants further exploration.