David C. Bartlett

Impact of wound edge protection devices on surgical site infection after laparotomy: multicentre randomised controlled trial (ROSSINI Trial).

Objective To determine the clinical effectiveness of wound edge protection devices in reducing surgical site infection after abdominal surgery. Design Multicentre observer blinded randomised controlled trial. Participants Patients undergoing laparotomy at 21 UK hospitals. Interventions Standard care or the use of a wound edge protection device during surgery. Main outcome measures Surgical site infection within 30 days of surgery, assessed by blinded clinicians at seven and 30 days and by patient’s self report for the intervening period. Secondary outcomes included quality of life, duration of stay in hospital, and the effect of characteristics of the patient and operation on the efficacy of the device. Results 760 patients were enrolled with 382 patients assigned to the device group and 378 to the control group. Six patients in the device group and five in the control group did not undergo laparotomy. Fourteen patients, seven in each group, were lost to follow-up. A total of 184 patients experienced surgical site infection within 30 days of surgery, 91/369 (24.7%) in the device group and 93/366 (25.4%) in the control group (odds ratio 0.97, 95% confidence interval 0.69 to 1.36; P=0.85). This lack of benefit was consistent across wound assessments performed by clinicians and those reported by patients and across all secondary outcomes. In the secondary analyses no subgroup could be identified in which there was evidence of clinical benefit associated with use of the device. Conclusions Wound edge protection devices do not reduce the rate of surgical site infection in patients undergoing laparotomy, and therefore their routine use for this role cannot be recommended. Trial registration Current Controlled Trials ISRCTN 40402832

Isolation of Primary Human Hepatocytes from Normal and Diseased Liver Tissue: A One Hundred Liver Experience

Successful and consistent isolation of primary human hepatocytes remains a challenge for both cell-based therapeutics/transplantation and laboratory research. Several centres around the world have extensive experience in the isolation of human hepatocytes from non-diseased livers obtained from donor liver surplus to surgical requirement or at hepatic resection for tumours. These livers are an important but limited source of cells for therapy or research. The capacity to isolate cells from diseased liver tissue removed at transplantation would substantially increase availability of cells for research. However no studies comparing the outcome of human hepatocytes isolation from diseased and non-diseased livers presently exist. Here we report our experience isolating human hepatocytes from organ donors, non-diseased resected liver and cirrhotic tissue. We report the cell yields and functional qualities of cells isolated from the different types of liver and demonstrate that a single rigorous protocol allows the routine harvest of good quality primary hepatocytes from the most commonly accessible human liver tissue samples.

Human mesenchymal stem cells are recruited to injured liver in a β1‐integrin and CD44 dependent manner

Human bone marrow mesenchymal stem cells (hMSCs) have shown benefit in clinical trials of patients with liver disease. Efficient delivery of cells to target organs is critical to improving their effectiveness. This requires an understanding of the mechanisms governing cellular engraftment into the liver. Binding of hMSCs to normal/injured liver tissue, purified extracellular matrices, and human hepatic sinusoidal endothelial cells (HSECs) were quantified in static and flow conditions. To define the mechanisms underpinning hMSC interactions, neutralizing adhesion molecule antibodies were used. Fluorescently labelled hMSCs were infused intraportally into CCl4–injured mice with and without neutralizing antibodies. hMSCs expressed high levels of CD29/β1‐integrin and CD44. Using liver tissue binding assays, hMSC adhesion was greatest in diseased human liver versus normal liver (32.2 cells/field versus 20.5 cells/field [P = 0.048]). Neutralizing antibodies against CD29 and CD44 reduced hMSC binding to diseased liver by 34% and 35%, respectively (P = 0.05). hMSCs rolled at 528 μm/second on HSECs in flow assays. This rolling was abolished by CD29 blockade on hMSCs and vascular cell adhesion molecule‐1 (VCAM‐1) blockade on HSECs. Firm adhesion to HSECs was reduced by CD29 (55% [P = 0.002]) and CD44 (51% [P = 0.04]) blockade. Neutralizing antibodies to CD29 and CD44 reduced hepatic engraftment of hMSCs in murine liver from 4.45 cells/field to 2.88 cells/field (P = 0.025) and 2.35 cells/field (P = 0.03), respectively. hMSCs expressed modest levels of chemokine receptors including CCR4, CCR5, and CXCR3, but these made little contribution to hMSC adhesion in this setting. Conclusion: hMSCs bind preferentially to injured liver. Rolling of hMSCs is regulated by CD29/VCAM‐1, whereas CD29/CD44 interactions with VCAM‐1, fibronectin, and hyaluronan on HSECs determine firm adhesion both in vitro and in vivo as demonstrated using a murine model of liver injury. (HEPATOLOGY 2012;56:1063–1073)

Systematic review of the clinical effectiveness of wound-edge protection devices in reducing surgical site infection in patients undergoing open abdominal surgery

Objective:Assess the existing evidence on the clinical effectiveness of wound-edge protection devices (WEPDs) in reducing the surgical site infection (SSI) rate in patients undergoing open abdominal surgery. Background:Surgical site infections are a common postoperative complication associated with considerable morbidity, extended hospital stay, increased health care costs, and reduced quality of life. Wound-edge protection devices have been used in surgery to reduce SSI rates for more than 40 years; however, they are yet to be cited in major clinical guidelines addressing SSI management. Methods:A review protocol was prespecified. A variety of sources were searched in November 2010 for studies containing primary data on the use of WEPDs in reducing SSI compared with standard care in patients undergoing open abdominal surgery. The outcome of interest was a well-specified, clinically based definition of an SSI. No language or time restrictions were applied. The quality assessment of the studies and the quantitative analyses were performed in line with the principles of the Cochrane Collaboration. Results:Twelve studies reporting primary data from 1933 patients were included in the review. The quality assessment found all of them to be at considerable risk of bias. An exploratory meta-analysis was performed to provide a quantitative indication on the effect of WEPDs. The pooled risk ratio under a random effects model was 0.60 (95% confidence interval, 0.41–0.86), indicating a potentially significant benefit from the use of WEPDs. No indications of significant between-study heterogeneity or publication bias, respectively, were identified. Conclusions:Evidence to date suggests that WEPDs may be efficient in reducing SSI rates in patients undergoing open abdominal surgery. However, the poor quality of the existing studies and their small sample sizes raise the need for a large, good quality randomized controlled trial to validate this indication.

How to set up and manage a trainee-led research collaborative

BackgroundEnsuring that doctors in training acquire sufficient knowledge, experience and understanding of medical research is a universal and longstanding issue which has been brought into sharper focus by the growth of evidence based medicine. All healthcare systems preparing doctors in training for practice have to balance the acquisition of specific clinical attitudes, knowledge and skills with the wider need to ensure doctors are equipped to remain professionally competent as medical science advances. Most professional medical bodies acknowledge that this requires trainee doctors to experience some form of research education, not only in order to carry out original research, but to acquire sufficient academic skills to become accomplished research consumers in order to remain informed throughout their professional practice. There are many barriers to accomplishing this ambitious aim.DiscussionThis article briefly explains why research collaboratives are necessary, describes how to establish a collaborative, and recommends how to run one. It is based on the experiences of the pioneering West Midlands Research Collaborative and draws on the wider literature about the organisation and delivery of high quality research projects. Practical examples of collaborative projects are given to illustrate the potential of this form of research organisation.SummaryThe new trainee-led research collaboratives provide a supportive framework for planning, ownership and delivery of high quality multicentre research. This ensures clinical relevance, increases the chances of research findings being translated into changes in practice and should lead to improved patient outcomes. Research collaboratives also enhance the research skills and extend the scientific horizons of doctors in training.

Combined use of N-acetylcysteine and Liberase improves the viability and metabolic function of human hepatocytes isolated from human liver

Background aims Successful hepatocyte isolation is critical for continued development of cellular transplantation. However, most tissue available for research is from diseased liver, and the results of hepatocyte isolation from such tissue are inferior compared with normal tissue. Liberase and N-acetylcysteine (NAC) have been shown separately to improve viability of isolated hepatocytes. This study aims to determine the effect of Liberase and NAC in combination on human hepatocyte isolation from normal and diseased liver tissues. Methods Hepatocytes were isolated from 30 liver specimens through the use of a standard collagenase digestion technique (original protocol) and another 30 with the addition of NAC and standard collagenase substituted by Liberase (new protocol). Viability and success, defined as maintenance of cell adhesion and morphology for 48 hours, were assessed. Metabolic function was assessed by means of albumin and urea synthesis. Results Baseline factors were similar for both groups. The delay to tissue processing was slightly shorter in the new protocol group (median, 2 versus 4 hours; P = 0.007). The success rate improved from 12 of 30 (40.0%) to 21 of 30 (70.0%) with the use of the new protocol (P = 0.037), and median viable cell yield increased from 7.3 × 104 to 28.3 × 104 cells/g tissue (P = 0.003). After adjusting for delay, success rate (P = 0.014) and viable cell yield/g tissue (P = 0.001) remained significantly improved. Albumin and urea synthesis were similar or superior in the new protocol group. Conclusions NAC and Liberase improve the success of hepatocyte isolation, with a significantly higher yield of viable cells. The use of these agents may improve the availability of hepatocytes for transplantation and laboratory research.

Plasma succinylacetone is persistently raised after liver transplantation in tyrosinaemia type 1.

BackgroundTyrosinaemia type 1 (HT1) is a rare disorder leading to accumulation of toxic metabolites such as succinylacetone (SA) and a high risk of hepatocellular carcinoma. Children with HT1 traditionally required liver transplantation (OLT) and while the need for this has been reduced by the introduction of nitisinone some still require OLT. SA inhibits the enzyme porphobilinogen (PBG) synthase and its activity can be used as a marker of active SA. Elevated urinary SA post OLT has been reported previously. This study describes a novel finding of elevated plasma SA following OLT for HT1.MethodsA retrospective analysis was performed of patients treated for HT1 at our institution from 1989-2010.ResultsThirteen patients had an OLT for HT1. In patients who received nitisinone prior to OLT, mean urinary and plasma SA were elevated prior to treatment but normalised by the time of OLT (p ≤ 0.01). Mean PBG synthase activity increased from 0.032 to 0.99 nkat/gHb (ref range 0.58-1.25) at the time of OLT (p < 0.01). Mean urinary SA in patients not treated with nitisinone was also elevated prior to OLT; plasma levels and PBG synthase activity were not available prior to OLT for this group. Following OLT, mean urinary and plasma SA were elevated in all for the duration of follow-up and associated with low-normal PBG synthase activity.ConclusionUrinary and plasma SA levels are elevated following OLT for HT1. Low-normal PBG synthase activity suggests the plasma SA may be active. The clinical significance of this is unclear.

The Cost-Effectiveness of Wound-Edge Protection Devices Compared to Standard Care in Reducing Surgical Site Infection after Laparotomy: An Economic Evaluation alongside the ROSSINI Trial

Background Wound-edge protection devices (WEPDs) have been used in surgery for more than 40 years to reduce surgical site infection (SSI). No economic evaluation of WEPDs against any comparator has ever been conducted. The aim of the paper was to assess whether WEPDs are cost-effective in reducing SSI compared to standard care alone in the United Kingdom. Methods and Findings An economic evaluation was conducted alongside the ROSSINI trial. The study perspective was that of the UK National Health Service and the time horizon was 30 days post-operatively. The study was conducted in 21 UK hospitals. 760 patients undergoing laparotomy were randomised to either WEPD or standard care and 735 were included in the primary analysis. The main economic outcome was cost-effectiveness based on incremental cost (£) per quality adjusted life year (QALY) gained. Patients in the WEPD arm accessed health care worth £5,420 on average and gained 0.02131 QALYs, compared to £5,130 and 0.02133 QALYs gained in the standard care arm. The WEPD strategy was more costly and equally effective compared to standard care, but there was significant uncertainty around incremental costs and QALYs. The findings were robust to a range of sensitivity analyses. Conclusions There is no evidence to suggest that WEPDs can be considered a cost effective device to reduce SSI. Their continued use is a waste of limited health care resources.

Hepatocyte cell therapy in liver disease

Liver disease is a leading cause of morbidity and mortality. Liver transplantation remains the only proven treatment for end-stage liver failure but is limited by the availability of donor organs. Hepatocyte cell therapy, either with bioartificial liver devices or hepatocyte transplantation, may help address this by delaying or preventing liver transplantation. Early clinical studies have shown promising results, however in most cases, the benefit has been short lived and so further research into these therapies is required. Alternative sources of hepatocytes, including stem cell-derived hepatocytes, are being investigated as the isolation of primary human hepatocytes is limited by the same shortage of donor organs. This review summarises the current clinical experience of hepatocyte cell therapy together with an overview of possible alternative sources of hepatocytes. Current and future areas for research that might lead towards the realisation of the full potential of hepatocyte cell therapy are discussed.

Reduction of surgical site infection using a novel intervention (ROSSINI): study protocol for a randomised controlled trial

BackgroundSurgical site infection (SSI) is a common complication following abdominal surgery. It is associated with considerable morbidity and mortality, and its management results in significant cost to health services within both primary and secondary care. Some surgeons believe that the use of a wound-edge protection device may reduce the incidence of SSI. Whilst there is some encouraging evidence showing that such devices may lead to a reduction in SSI, there are no controlled trials of sufficient size or quality to support their routine use.Methods/Design750 patients will be recruited from around 20 surgical units within the United Kingdom. Patients undergoing laparotomy through any major abdominal incision for any indication, elective or emergency, are eligible. Patients under the age of 18, those undergoing a laparoscopic assisted procedure or who have undergone laparotomy within the previous 3 months, and those who are unable to give informed consent will be excluded. Patients will be randomised (1:1 ratio) to the use of a wound-edge protection device or no wound-edge protection device during surgery.Follow up will consist of blinded clinical wound reviews at 5-7 days and 30-33 days postoperatively with a self-completed questionnaire covering the intervening period. Quality of life questionnaires will be completed prior to surgery and at the subsequent wound review points and information on resource usage will also be captured.The primary outcome measure is SSI within 30 days of surgery. Secondary outcomes include the impact of the degree of wound contamination, patient comorbidity, and operative characteristics on the efficacy of a wound-edge protection device in reducing SSI and whether the use of a wound-edge protection device has an effect on health-related quality of life or length of hospital stay and is cost-effective.DiscussionRossini is the first multicentre observer-blinded randomised controlled trial of sufficient size and quality to establish whether the use of a wound-edge protection device in adult patients undergoing abdominal surgery leads to a lower rate of SSI. The results of this study will be used to inform current surgical practice and may potentially benefit patients undergoing surgery in the future.Trial registration numberCurrent Controlled Trials ISRCTN: ISRCTN40402832