ObjectiveAcute liver failure (ALF) is characterised by overwhelming hepatocyte death and liver inflammation with massive infiltration of myeloid cells in necrotic areas. The mechanisms underlying resolution of acute hepatic inflammation are largely unknown. Here, we aimed to investigate the impact of Mer tyrosine kinase (MerTK) during ALF and also examine how the microenvironmental mediator, secretory leucocyte protease inhibitor (SLPI), governs this response.DesignFlow cytometry, immunohistochemistry, confocal imaging and gene expression analyses determined the phenotype, functional/transcriptomic profile and tissue topography of MerTK+ monocytes/macrophages in ALF, healthy and disease controls. The temporal evolution of macrophage MerTK expression and its impact on resolution was examined in APAP-induced acute liver injury using wild-type (WT) and Mer-deficient (Mer−/−) mice. SLPI effects on hepatic myeloid cells were determined in vitro and in vivo using APAP-treated WT mice.ResultsWe demonstrate a significant expansion of resolution-like MerTK+HLA-DRhigh cells in circulatory and tissue compartments of patients with ALF. Compared with WT mice which show an increase of MerTK+MHCIIhigh macrophages during the resolution phase in ALF, APAP-treated Mer−/− mice exhibit persistent liver injury and inflammation, characterised by a decreased proportion of resident Kupffer cells and increased number of neutrophils. Both in vitro and in APAP-treated mice, SLPI reprogrammes myeloid cells towards resolution responses through induction of a MerTK+HLA-DRhigh phenotype which promotes neutrophil apoptosis and their subsequent clearance.ConclusionsWe identify a hepatoprotective, MerTK+, macrophage phenotype that evolves during the resolution phase following ALF and represents a novel immunotherapeutic target to promote resolution responses following acute liver injury.

Anal fistula repair still remains challenging. Up to 30% of fistulas persist after surgery despite many improvements in surgical skills and technique. One major reason for surgical failure is a persistent fistula track or remnants of the fistula epithelium which could not be removed during surgery. To overcome this problem, a novel technique was developed using a newly invented radial emitting laser probe ("FiLaC™", Biolitec, Germany) to destroy the fistula epithelium and to simultaneously obliterate the remaining fistula track. In a pilot study, we operated on 11 patients with cryptoglandular anal fistula. All patients underwent previous surgery up to 6 times prior to definitive surgery. In the primary operation, the initial abscess was drained, the internal opening of the fistula identified and seton drainage placed. During fistula repair, we used the flap technique for conventional closure of the internal opening. The remaining fistula track was cleaned mechanically, the laser inserted into the track and energy applied homogeneously at a wavelength of 1,470 nm and 13 watt. While providing continuous retraction of the probe, the remaining epithelium was destroyed and the fistula track obliterated. The median follow-up was 7.4 months. Nine out of 11 fistulas showed primary healing (81.8%). Only one minor form of incontinence (limited soiling) was observed and no complications occurred. The use of a novel diode laser source and a radial emitting laser probe in addition to conventional surgery is a very promising new technique in sphincter-preserving anal fistula repair. The observed healing rate is high. Due to minimized trauma to the sphincter muscle, there are good short-term functional results without observable procedure-related complications.

Background There are limited data available concerning endofistular therapies for fistula-in-ano, with our group reporting the first preliminary outcomes of the use of the radial fibre Fistula laser Closing (FiLaC ™) device.MethodsThe aim of this study was to assess a cohort of anal fistulae managed with laser ablation plus definitive flap closure of the internal fistula opening over a long-term follow-up. Factors governing primary healing success and secondary healing success (i.e. success after one or two operations) were determined.Results The study analysed 117 patients over a median follow-up period of 25.4 months (range 6–60 months) with 13 patients (11.1%) having Crohn’s-related fistulae. No incontinence to solid and liquid stool was reported. Minor incontinence to mucus and gas was observed in two cases (1.7%), and a late abscess treated in one case (0.8%). The primary healing rate was 75/117 (64.1%) overall, and 63.5% for cryptoglandular fistulae versus 69.2% for Crohn’s fistulae, respectively. Of the 42 patients who failed FiLaC™ 31 underwent a second operation (“Re-FiLaC™”, fistulectomy with sphincter reconstruction or fistulotomy). The secondary healing rate, defined as healing of the fistula at the end of the study period, was 103/117 (88.0%) overall and 85.5% for cryptoglandular fistulae versus 92.3% for Crohn’s fistulae. A significantly higher primary success rate was observed for intersphincteric-type fistulae with primary and secondary outcome unaffected by age, gender, presence of Crohn’s disease, number of prior surgeries and the type of flap designed to close the internal fistula opening.ConclusionsThere is a moderate primary success rate using first-up FiLaC™ treatment. If FiLaC™ fails, secondary success with repeat FiLaC™ or other approaches was high. The minimally invasive FiLaC™ approach may therefore represent a sensible first-line treatment option for anal fistula repair.

IntroductionCD248 (endosialin) is a stromal cell marker expressed on fibroblasts and pericytes. During liver injury, myofibroblasts are the main source of fibrotic matrix.ObjectiveTo determine the role of CD248 in the development of liver fibrosis in the rodent and human setting.DesignCD248 expression was studied by immunostaining and quantitative PCR in both normal and diseased human and murine liver tissue and isolated hepatic stellate cells (HSCs). Hepatic fibrosis was induced in CD248−/− and wild-type controls with carbon tetrachloride (CCl4) treatment.ResultsExpression of CD248 was seen in normal liver of humans and mice but was significantly increased in liver injury using both immunostaining and gene expression assays. CD248 was co-expressed with a range of fibroblast/HSC markers including desmin, vimentin and α-smooth muscle actin (α-SMA) in murine and human liver sections. CD248 expression was restricted to isolated primary murine and human HSC. Collagen deposition and α-SMA expression, but not inflammation and neoangiogenesis, was reduced in CD248−/− mice compared with wild-type mice after CCl4 treatment. Isolated HSC from wild-type and CD248−/− mice expressed platelet-derived growth factor receptor α (PDGFR-α) and PDGFR-β at similar levels. As expected, PDGF-BB stimulation induced proliferation of wild-type HSC, whereas CD248−/− HSC did not demonstrate a proliferative response to PDGF-BB. Abrogated PDGF signalling in CD248−/− HSC was confirmed by significantly reduced c-fos expression in CD248−/− HSC compared with wild-type HSC.ConclusionsOur data show that deletion of CD248 reduces susceptibility to liver fibrosis via an effect on PDGF signalling, making it an attractive clinical target for the treatment of liver injury.