Quantifying changes in innate immune function following liver transplantation for chronic liver disease

BACKGROUND

Liver transplantation (LT) offers patients with cirrhosis long-term survival, however many die from sepsis whilst awaiting LT. The liver's role in innate immunity may be key to improving outcomes, but the immune effects of LT have not been quantified.

METHODS

Innate immune capacity was assessed by clearance of ^99mTc-Albumin nanospheres in patients with chronic liver failure before and after LT.

RESULTS

Twenty-eight patients with chronic liver disease on the LT waiting list entered the study during the twelve-month study period and nine patients underwent LT and completed the study protocol. One patient developed hepatic artery thrombosis in <7 days and was excluded from the study. Innate immune function was significantly impaired in patients with chronic liver disease on the LT waiting list and this was directly correlated with MELD score. LT normalised innate immune function by day 1 post LT with further improvement occurring by day 7 post LT. Donor liver weight was the only factor correlated with innate immune function at day 1 post LT but this effect was negated by day 7 post LT.

CONCLUSION

Recognising the immune effects of LT may facilitate treatment of cirrhosis and inform development of extracorporeal liver support systems.

Pancreatic cystic lesions: risk stratification and management based on recent guidelines

Pancreatic cystic lesions (PCLs) can present complex diagnostic and management challenges with uncertainty as to the most appropriate investigations, interventions and surveillance. Guidelines have been developed to aid decision making, including the European Study Group, American College of Gastroenterology and International Study Group guidelines. This paper presents issues relating to risk stratification and the appropriate management of patients with PCLs, reviewing these recently published guidelines. While there are similarities across these expert guidelines, there are notable differences in terms of features associated with increased risk of malignant transformation, the most appropriate imaging modality and timing of interval imaging. Where variations exist, this reflects differing interpretations of a limited evidence base, and decision making will likely evolve further as experience with these guidelines develops.

CSF1 Restores Innate Immunity After Liver Injury in Mice and Serum Levels Indicate Outcomes of Patients With Acute Liver Failure

BACKGROUND & AIMS

Liver regeneration requires functional liver macrophages, which provide an immune barrier that is compromised after liver injury. The numbers of liver macrophages are controlled by macrophage colony-stimulating factor (CSF1). We examined the prognostic significance of the serum level of CSF1 in patients with acute liver injury and studied its effects in mice.

METHODS

We measured levels of CSF1 in serum samples collected from 55 patients who underwent partial hepatectomy at the Royal Infirmary Edinburgh between December 2012 and October 2013, as well as from 78 patients with acetaminophen-induced acute liver failure admitted to the Royal Infirmary Edinburgh or the University of Kansas Medical Centre. We studied the effects of increased levels of CSF1 in uninjured mice that express wild-type CSF1 receptor or a constitutive or inducible CSF1-receptor reporter, as well as in chemokine receptor 2 (Ccr2)-/- mice; we performed fate-tracing experiments using bone marrow chimeras. We administered CSF1-Fc (fragment, crystallizable) to mice after partial hepatectomy and acetaminophen intoxication, and measured regenerative parameters and innate immunity by clearance of fluorescent microbeads and bacterial particles.

RESULTS

Serum levels of CSF1 increased in patients undergoing liver surgery in proportion to the extent of liver resected. In patients with acetaminophen-induced acute liver failure, a low serum level of CSF1 was associated with increased mortality. In mice, administration of CSF1-Fc promoted hepatic macrophage accumulation via proliferation of resident macrophages and recruitment of monocytes. CSF1-Fc also promoted transdifferentiation of infiltrating monocytes into cells with a hepatic macrophage phenotype. CSF1-Fc increased innate immunity in mice after partial hepatectomy or acetaminophen-induced injury, with resident hepatic macrophage as the main effector cells.

CONCLUSIONS

Serum CSF1 appears to be a prognostic marker for patients with acute liver injury. CSF1 might be developed as a therapeutic agent to restore innate immune function after liver injury.

Polysialic acid/neural cell adhesion molecule modulates the formation of ductular reactions in liver injury

In severe liver injury, ductular reactions (DRs) containing bipotential hepatic progenitor cells (HPCs) branch from the portal tract. Neural cell adhesion molecule (NCAM) marks bile ducts and DRs, but not mature hepatocytes. NCAM mediates interactions between cells and surrounding matrix; however, its role in liver development and regeneration is undefined. Polysialic acid (polySia), a unique posttranslational modifier of NCAM, is produced by the enzymes, ST8SiaII and ST8SiaIV, and weakens NCAM interactions. The role of polySia with NCAM synthesizing enzymes ST8SiaII and ST8SiaIV were examined in HPCs in vivo using the choline-deficient ethionine-supplemented and 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet models of liver injury and regeneration, in vitro using models of proliferation, differentiation, and migration, and by use of mouse models with gene defects in the polysialyltransferases (St8sia 2+/-4+/-, and St8sia2-/-4-/-). We show that, during liver development, polySia is required for the correct formation of bile ducts because gene defects in both the polysialyltransferases (St8sia2+/-4+/- and St8sia2-/-4-/- mice) caused abnormal bile duct development. In normal liver, there is minimal polySia production and few ductular NCAM+ cells. Subsequent to injury, NCAM+ cells expand and polySia is produced by DRs/HPCs through ST8SiaIV. PolySia weakens cell-cell and cell-matrix interactions, facilitating HGF-induced migration. Differentiation of HPCs to hepatocytes in vitro results in both transcriptional down-regulation of polySia and cleavage of polySia-NCAM. Cleavage of polySia by endosialidase (endoN) during liver regeneration reduces migration of DRs into parenchyma.

CONCLUSION

PolySia modification of NCAM+ ductules weakens cell-cell and cell-matrix interactions, allowing DRs/HPCs to migrate for normal development and regeneration. Modulation of polySia levels may provide a therapeutic option in liver regeneration.

Systematic review: the effects of autologous stem cell therapy for patients with liver disease

BACKGROUND

As morbidity and mortality from liver disease continues to rise, new strategies are necessary. Liver transplantation is not only an expensive resource committing the patient to lifelong immunosuppression but also suitable donor organs are in short supply. Against this background, autologous stem cell therapy has emerged as a potential treatment option.

AIM

To evaluate if it is possible to make a judgement on the safety, feasibility and effect of autologous stem cell therapy for patients with liver disease.

METHODS

MEDLINE and EMBASE were searched up until July 2013 to identify studies where autologous stem cell therapy was administered to patients with liver disease.

RESULTS

Of 1668 studies identified, 33 were eligible for inclusion evaluating a median sample size of 10 patients for a median follow-up of 6 months. Although there was marked heterogeneity between studies with regards to type, dose and route of delivery of stem cell, the treatment was shown to be safe and feasible largely when a peripheral route of administration was used. Of the studies which also looked at biochemical outcome, statistically significant improvement in liver function tests was seen in 16 studies post-treatment.

CONCLUSION

Although autologous stem cell therapy is a much needed possibility in the treatment of liver disease, further robust clinical trials and collaborative protocols are required.

Outcomes following a dedicated period of research during surgical training

With recent 'working-time'-related changes to surgical training structure, the value of dedicated research during surgical training has been questioned. Online survey examining career and academic outcomes following a period of surgically related dedicated research at a Scottish University between 1972 and 2007. Of 58 individuals identified, contact details were available for 49 and 43 (88%) responded. Ninety-five percent (n = 41) of respondents continue to pursue a career in surgery and 41% (n = 17) are currently in academic positions. Ninety-one percent (n = 39) had published one or more first-author peer-reviewed articles directly related to their research, with 53% (n = 23) publishing three or more. Respondents with a clinical component to their research published significantly more papers than those with purely laboratory-based research (P = 0.04). Eighty-one percent (n = 35) thought that research was necessary for career progression, but only 42% (n = 18) felt research should be integral to training. In conclusion, the majority of surgical trainees completing a dedicated research period, published papers and continued to pursue a surgical career with a research interest. A period of dedicated research was thought necessary for career progression, but few thought dedicated research should be integral to surgical training.

Systematic review and meta-analysis of survival following extracorporeal liver support

Background

Extracorporeal liver support (ELS) systems offer the potential to prolong survival in acute and acute-on-chronic liver failure. However, the literature has been unclear on their specific role and influence on mortality. This meta-analysis aimed to test the hypothesis that ELS improves survival in acute and acute-on-chronic liver failure.

Methods

Clinical trials citing MeSH terms ‘liver failure’ and ‘liver, artificial’ were identified by searching MEDLINE, Embase and the Cochrane registry of randomized controlled trials (RCTs) between January 1995 and January 2010. Only RCTs comparing ELS with standard medical therapy in acute or acute-on-chronic liver failure were included. A predefined data collection pro forma was used and study quality assessed according to Consolidated Standards of Reporting Trials (CONSORT) criteria. Risk ratio was used as the effect size measure according to a random-effects model.

Results

The search strategy revealed 74 clinical studies including 17 RCTs, five case–control studies and 52 cohort studies. Eight RCTs were suitable for inclusion, three addressing acute liver failure (198 participants) and five acute-on-chronic liver failure (157 participants). The mean CONSORT score was 14 (range 11–20). Overall ELS therapy significantly improved survival in acute liver failure (risk ratio 0·70; P = 0·05). The number needed to treat to prevent one death in acute liver failure was eight. No significant survival benefit was demonstrated in acute-on-chronic liver failure (risk ratio 0·87; P = 0·37).

Conclusion

ELS systems appear to improve survival in acute liver failure. There is, however, no evidence that they improve survival in acute-on-chronic liver failure.

Pseudo-recurrence following laparoscopic ventral and incisional hernia repair

PURPOSE

Laparoscopic mesh repair is an established alternative to the open repair of herniae of the antero-lateral abdominal wall. However, a definition in the literature of "recurrence" is lacking. This study reviews the phenomenon of pseudo-recurrence in patients who describe recurrent symptoms despite an apparently successful laparoscopic ventral or incisional hernia repair (LVIHR).

METHODS

Cases of LVIHR from 1st January 2004 to 31st December 2007 were identified from the Lothian Surgical Audit database. Patients were contacted by telephone after a minimum of 11 months following operation. Pseudo-recurrences were identified by history and clinical examination, together with radiological investigation if the diagnosis remained in doubt.

RESULTS

One hundred and forty-three repairs were performed in the study period. One hundred and twenty-one patients were contacted (63 incisional and 58 other ventral herniae). Twenty possible recurrences were reported (16.5%). Four were true recurrences and two more were new incisional herniae. There were 14 pseudo-recurrences, arising after 12 incisional and two other ventral hernia repairs. These were due to mesh bulge (10), seroma (3) and retained hernia contents (1).

CONCLUSION

True recurrences after LVIHR do occur but should be preventable with good surgical technique. Pseudo-recurrences are more common and may mimic true recurrence. We recommend computed tomography (CT) to clarify the diagnosis and determine the indication for revisional surgery.

Prospects for stem cell transplantation in the treatment of hepatic disease

Stem cell therapy has the potential to provide a valuable adjunct to the management of hepatic disease. Preclinical studies have demonstrated a range of endogenous repair processes that can be exploited through stem cell therapy. Initial translational studies have been encouraging and have suggested improved liver function in advanced chronic liver disease and enhanced liver regeneration after portal vein embolization. This article reviews the potential for stem cell therapies to enhance hepatic regeneration in acute and chronic hepatic disease and is based on a MEDLINE and PubMed search for English language articles investigating mechanisms of hepatic regeneration and delivery of cell therapies. Two main mechanisms of potential stem cell therapy delivery have emerged: (1) a direct contribution to the functional hepatocyte population with embryonic, induced pluripotent, or adult stem cells and (2) the promotion of endogenous regenerative processes with bone marrow-derived stem cells. Bioartificial hepatic support systems may be proven to be an effective method of using ex vivo differentiated hepatocytes and be indicated as a bridging therapy to definitive surgery in acute liver failure. The administration of bone marrow-derived stem cells may enhance liver regeneration in chronic liver disease after portal vein embolization and could facilitate regeneration after partial hepatic resection. Ultimately, the most appropriate hepatic disease targets for stem cell therapies will become apparent as mechanisms of stem involvement in hepatic regeneration are further elucidated.

Distal pancreatectomy: what is the standard for laparoscopic surgery?

BACKGROUND/AIMS

Distal pancreatectomy (DP) is performed for a range of benign and malignant lesions. Accurate pre-operative diagnosis can be unreliable and morbidity remains high. This study evaluates a 12-year, single-centre experience with open DP to review indications, diagnoses and associated morbidity.

METHODS

Retrospective review of patients who underwent DP at a UK-based tertiary referral centre between 1994 and 2006.

RESULTS

Sixty-five patients (mean age 49.9 years) had final diagnoses of chronic pancreatitis +/- pseudocyst (n= 22), benign cystadenoma (n= 15), neuroendocrine tumour (n= 8), primary pancreatic carcinoma (n= 6) and 14 other conditions. DP performed for presumed cystic neoplasm (n= 24) revealed a correct pre-operative diagnosis in 71% of patients. Histological examination confirmed that 59% of resected cystic tumours were either malignant or had malignant potential. When DP was undertaken for presumed pseudocyst (n= 12), 83% of cases were correctly diagnosed pre-operatively. Overall mortality and morbidity rates were 3% and 39%, respectively, with five patients (8%) developing a clinically significant pancreatic fistula. Ten (17%) patients developed diabetes mellitus and nine (14%) required long-term pancreatic exocrine supplementation.

CONCLUSIONS

Open DP can be performed with acceptable morbidity, low mortality and preservation of pancreatic function in the majority of cases, setting the standard for laparoscopic techniques.