Reversibility of liver fibrosis

Liver fibrosis, and its end stage cirrhosis are a major cause of morbidity and mortality and therapeutic options are limited. However, the traditional view of liver disease as an irreversible process is obsolete and it is now evident that the development of liver fibrosis is a dynamic and potentially bidirectional process. Spontaneous resolution of scarring is seen in animal models of liver fibrosis and in human trials in which the stimuli responsible for chronic or repeated hepatic inflammation is successfully removed. Key players in the process are hepatic stellate cells, macrophages, MMPs and their inhibitors Timps. It is also evident that in advanced fibrotic liver disease, specific histological features define what is currently described as "irreversible" fibrosis. This includes the development of paucicellular scars enriched in extensively cross-linked matrix components, such as fibrillar collagen and elastin. Our recent work has focused on the role of macrophage metalloelastase (MMP-12) in the turnover of elastin in reversible and irreversible models of fibrosis. We have shown that elastin turnover in liver injury and fibrosis is regulated by macrophages via Mmp-12 expression, activity and ratio to its inhibitor Timp-1. Failure of elastin degradation, together with increased deposition leads to accumulation of elastin in the fibrotic scars

A Complete Expression Profile of Matrix-Degrading Metalloproteinases in Dupuytren’s Disease

Dupuytren’s disease (DD) is a common fibrotic condition of the palmar fascia, leading to deposition of collagen-rich cords and finger contractions. The metzincin superfamily contains key enzymes in the turnover of collagen and other extracellular matrix macromolecules. A number of broad-spectrum matrix metalloproteinase inhibitors, used in cancer clinical trials, caused side effects of DD-like contractures. We tested the hypothesis that changes in the expression of specific metalloproteinases underlie or contribute to the fibrosis and contracture seen in DD. We collected tissue from patients with DD and used normal palmar fascia as a control. We profiled the expression of the entire matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinases (TIMP), and a disintegrin and metalloproteinase domain with thrombospondin motif (ADAMTS) gene families in these tissues using real-time reverse-transcription polymerase chain reaction. A number of metalloproteinases and inhibitors are regulated in DD. The expression of 3 key collagenases, MMP1, MMP13, and MMP14 is increased significantly in the DD nodule, as is the expression of the collagen biosynthetic enzyme ADAMTS14. The expression of MMP7, an enzyme with broad substrate specificity, is increased in the DD nodule and remains equally expressed in the DD cord. TIMP1 expression is increased significantly in DD nodule compared with normal palmar fascia. This study measured the expression of all MMP, ADAMTS, and TIMP genes in DD. Contraction and fibrosis may result from: (1) increased collagen biosynthesis mediated by increased ADAMTS-14; (2) an increased level of TIMP-1 blocking MMP-1– and MMP-13–mediated collagenolysis; and (3) contraction enabled by MMP-14–mediated pericellular collagenolysis (and potentially MMP-7), which may escape inhibition by TIMP-1. The complete expression profile will provide a knowledge-based approach to novel therapeutics targeting these genes

A prospective cohort study assessing clinical referral management & workforce allocation within a UK regional medical genetics service

Abstract Ensuring patient access to genomic information in the face of increasing demand requires clinicians to develop innovative ways of working. This paper presents the first empirical prospective observational cohort study of UK multi-disciplinary genetic service delivery. It describes and explores collaborative working practices including the utilisation and role of clinical geneticists and non-medical genetic counsellors. Six hundred and fifty new patients referred to a regional genetics service were tracked through 850 clinical contacts until discharge. Referral decisions regarding allocation of lead health professional assigned to the case were monitored, including the use of initial clinical contact guidelines. Significant differences were found in the cases led by genetic counsellors and those led by clinical geneticists. Around a sixth, 16.8% (109/650) of referrals were dealt with by a letter back to the referrer or re-directed to another service provider and 14.8% (80/541) of the remaining patients chose not to schedule an appointment. Of the remaining 461 patients, genetic counsellors were allocated as lead health professional for 46.2% (213/461). A further 61 patients did not attend. Of those who did, 86% (345/400) were discharged after one or two appointments. Genetic counsellors contributed to 95% (784/825) of total patient contacts. They provided 93.7% (395/432) of initial contacts and 26.8% (106/395) of patients were discharged at that point. The information from this study informed a planned service re-design. More research is needed to assess the effectiveness and efficiency of different models of collaborative multi-disciplinary working within genetics services. Keywords (MeSH terms) Genetic Services, Genetic Counseling, Interdisciplinary Communication, Cohort Studies, Delivery of Healthcare, Referral and Consultation

Echoes of time. The mobility of Brazilian researchers and students in Portugal

A investigação que apresentamos, de caráter exploratório, recaiu sobre histórias biográficas de brasileiros que escolhem Portugal para prosseguir formação e ou investigação. Procura-se encontrar na sua experiência elos de ligação explicativos sobre as motivações e os processos que os trazem para Portugal, assim como as expetativas e os projetos que comportam para os seus futuros e que incluem, ou não, este país. Temos em conta, especialmente, a forma como essa narrativa transporta sentidos identitários decorrentes das formas de relacionamento intercultural e político entre Portugal e Brasil e formas de cooperação implícitas, assim como mapas representacionais acerca dos lugares de eleição para desenvolvimento de carreiras científicas e académicas. A nossa pesquisa incide sobre as informações recolhidas através de um inquérito por questionário e entrevistas realizadas junto de estudantes e bolseiros brasileiros em Portugal.We present an exploratory study that investigated biographical stories of Brazilians who choose to continue their education or develop research in Portugal. We sought to find in their experiences explanatory links connecting the motivations and processes that bring them to Portugal, as well as the expectations and projects that they hold for the future, which may include, or not, this country. We take into account, particularly, the way this narrative carries senses of identity arising from the forms of intercultural and political relationship between Portugal and Brazil, as well as implicit forms of cooperation and representations about the places chosen for the development of scientific and academic careers. Our research draws on information collected through a survey based on questionnaires and interviews with Brazilian students and scholarship holders in Portugal.(undefined

Verbal Learning and Memory in Cannabis and Alcohol Users: An Event-Related Potential Investigation

Aims: Long-term heavy use of cannabis and alcohol are known to be associated withmemory impairments. In this study, we used event-related potentials to examine verballearning and memory processing in a commonly used behavioral task.Method: We conducted two studies: first, a small pilot study of adolescent males,comprising 13 Drug-Naive Controls (DNC), 12 heavy drinkers (HD) and 8 cannabis users(CU). Second, a larger study of young adults, comprising 45 DNC (20 female), 39 HD (16female), and 20 CU (9 female). In both studies, participants completed a modified verballearning task (the Rey Auditory Verbal Learning Test, RAVLT) while brain electrical activitywas recorded. ERPs were calculated for words which were subsequently rememberedvs. those which were not remembered, and for presentations of learnt words, previouslyseen words, and new words in a subsequent recognition test. Pre-planned principalcomponents analyses (PCA) were used to quantify the ERP components in these recalland recognition phases separately for each study.Results: Memory performance overall was slightly lower than published norms usingthe standardized RAVLT delivery, but was generally similar and showed the expectedchanges over trials. Few differences in performance were observed between groups; anotable exception was markedly poorer delayed recall in HD relative to DNC (Study 2).PCA identified components expected from prior research using other memory tasks. Atencoding, there were no between-group differences in the usual P2 recall effect (larger forrecalled than not-recalled words). However, alcohol-related differences were observed ina larger P540 (indexing recollection) in HD than DNC, and cannabis-related differenceswere observed in a smaller N340 (indexing familiarity) and a lack of previously seen > newwords effect for P540 in Study 2.Conclusions: This study is the first examination of ERPs in the RAVLT in healthycontrol participants, as well as substance-using individuals, and represents an importantadvance in methodology. The results indicate alterations in recognition memoryprocessing, which even if not manifesting in overt behavioral impairment, underline thepotential for brain dysfunction with early exposure to alcohol and cannabis

Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis

Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base

Bone marrow injection stimulates hepatic ductular reactions in the absence of injury via macrophage-mediated TWEAK signaling

Tissue progenitor cells are an attractive target for regenerative therapy. In various organs, bone marrow cell (BMC) therapy has shown promising preliminary results, but to date no definite mechanism has been demonstrated to account for the observed benefit in organ regeneration. Tissue injury and regeneration is invariably accompanied by macrophage infiltration, but their influence upon the progenitor cells is incompletely understood, and direct signaling pathways may be obscured by the multiple roles of macrophages during organ injury. We therefore examined a model without injury; a single i.v. injection of unfractionated BMCs in healthy mice. This induced ductular reactions (DRs) in healthy mice. We demonstrate that macrophages within the unfractionated BMCs are responsible for the production of DRs, engrafting in the recipient liver and localizing to the DRs. Engrafted macrophages produce the cytokine TWEAK (TNF-like weak inducer of apoptosis) in situ. We go on to show that recombinant TWEAK activates DRs and that BMC mediated DRs are TWEAK dependent. DRs are accompanied by liver growth, occur in the absence of liver tissue injury and hepatic progenitor cells can be isolated from the livers of mice with DRs. Overall these results reveal a hitherto undescribed mechanism linking macrophage infiltration to DRs in the liver and highlight a rationale for macrophage derived cell therapy in regenerative medicine

Increased Liver Uptake and Reduced Hepatic Stellate Cell Activation with a Cell-Specific Conjugate of the Rho-kinase Inhibitor Y27632

Rho-kinase regulates activation of hepatic stellate cells (HSC) during liver fibrosis, but the ubiquitous presence of this kinase may hinder examination of its exact role and the therapeutic use of inhibitors. We therefore coupled the Rho-kinase inhibitor Y27632 to a drug carrier that binds the mannose-6-phosphate insulin-like growth factor II (M6P/IGFII)-receptor which is upregulated on activated HSC. Y27632 was coupled to mannose-6-phosphate human serum albumin (M6PHSA), and in vitro experiments were performed on primary rat HSC. Biodistribution and effect studies were performed in an acute CCl(4) model in mice. Y27-conjugate remained stable in serum, while drug was efficiently released in liver homogenates. Receptor-blocking studies revealed that it was specifically taken up through the M6P/IGFII-receptor on fibroblasts, and it inhibited expression of fibrotic markers in activated HSC. In vivo, liver drug levels were significantly higher after injection of Y27-conjugate as compared to Y27632, and the conjugate accumulated specifically in HSC. After acute CCl(4)-induced liver injury, Y27-conjugate reduced the local activation of HSC, whereas an equimolar dose of free drug did not. We conclude that specific targeting of a Rho-kinase inhibitor to HSC leads to enhanced accumulation of the drug in HSC, reducing early fibrogenesis in the liver