Proteomic profiling in Lipocalin 2 deficient mice under normal and inflammatory conditions

Real life data: follow-up assessment on Spanish Gaucher disease patients treated with eliglustat. TRAZELGA project

BACKGROUND

The availability of multiple treatments for type 1 Gaucher disease increases the need for real-life studies to evaluate treatment efficacy and safety and provide clinicians with more information to choose the best personalized therapy for their patients.

AIMS

To determine whether treatment with eliglustat produces, in adult GD1 patients, ans optimal response in daily clinical practice.

METHODS

We designed a real-life study with 2 years of follow-up (TRAZELGA [GEE-ELI-2017-01]) to uniformly evaluate the response and adverse events to eliglustat treatment. This study, conducted in 30 patients across Spain and previously treated with other therapies, included the evaluation of safety and efficacy by assessing visceral enlargement, bone disease (DEXA and T and Z scores), concomitant treatments and adverse events, as well as a quality of life evaluation (SF-36). In addition, the quantification of classical biomarkers (chitotriosidase activity, CCL18/PARC and glucosylsphingosine (GluSph)) and new candidates for GD biomarkers (YKL-40, cathepsin S, hepcidin and lipocalin-2 determined by immunoassay) were also assessed. Non-parametric statistical analysis was performed and p < 0.05 was considered statistically significant.

MAIN RESULTS

Thirty patients were enrolled in the study. The median age was 41.5 years and the male-female ratio was 1.1:1. 84% of the patients had received ERT and 16% SRT as previous treatment. The most common symptoms at baseline were fatigue (42%) and bone pain (38%), no patient had a bone crisis during the study, and two years after switching, 37% had reduced their use of analgesics. Patient-reported outcomes showed a significant increase in physical function scores (p = 0.027) and physical pain scores (p = 0.010). None of the enrolled patients discontinued treatment due to adverse events, which were mild and transient in nature, mainly gastrointestinal and skin dryness. None of the biomarkers show a significant increase or decompensation after switching. CCL18/PARC (p = 0.0012), YKL-40 (p = 0.00004) and lipocalin-2 (p = 0.0155) improved after two years and GluSph after one year (p = 0.0008) and two years (p = 0.0245) of oral therapy.

CONCLUSION

In summary, this real-life study, showed that eliglustat maintains stability and can improve quality of life with few side effects. Significant reductions in classic and other novel biomarkers were observed after two years of therapy.

Distinct Patterns of GR Transcriptional Regulation in Liver and Muscle of LPS-Challenged Weaning Piglets

Glucocorticoid receptor (GR), which is ubiquitously expressed in nearly all cell types of various organs, mediates the tissue-specific metabolic and immune responses to maintain homeostasis and ensure survival under stressful conditions or pathological challenges. The neonatal period is metabolically demanding, and piglets are subjected to multiple stressors in modern intensive farms, especially around weaning. The liver is more responsive to LPS challenge compared to muscle, which is indicated by significantly increased TLR4 and p-p65, TNF-α, and IL-6 levels in association with GR down-regulation at both mRNA and protein levels. GR binding to the putative nGRE on TNF-α and IL-6 gene promoters decreased in the liver, but not muscle, upon LPS stimulation. The transcriptional regulation of GR also showed striking differences between liver and muscle. GR exon 1 mRNA variants 1–4, 1–5, and 1–6 were down-regulated in both liver and muscle, but a significant up-regulation of GR exon 1–9/10 mRNA variants abolished the change of total GR mRNA in the muscle in response to LPS stimulation. The significant down-regulation of GR in the liver corresponded with significantly decreased binding of p-GR and diminished histone acetylation in GR gene promoters. These results indicate that tissue-specific GR transcriptional regulation is involved in the differential inflammation responses between liver and muscle.

ITIH5-Derived Polypeptides Covering the VIT Domain Suppress the Growth of Human Cancer Cells In Vitro

Oncogenic drivers such as mutated EGFR are the preferred targets in modern drug development. However, restoring the lost function of tumor suppressor proteins could also be a valid approach to combatting cancer. ITIH5 has been revealed as a potent metastasis suppressor in both breast and pancreatic cancer. Here, we show that ITIH5 overexpression in MDA-MB-231 breast cancer cells can also locally suppress tumor growth by 85%, when transplanted into the mammary fat pad of nude mice. For a potential drug development approach, we further aimed to define downsized ITIH5 polypeptides that still are capable of mediating growth inhibitory effects. By cloning truncated and His-tagged ITIH5 fragments, we synthesized two recombinant N-terminal polypeptides (ITIH5681aa and ITIH5161aa), both covering the ITI heavy chain specific “vault protein inter-alpha-trypsin” (VIT) domain. Truncated ITIH5 variants caused dose-dependent cell growth inhibition by up to 50% when applied to various cancer cell lines (e.g., MDA-MB-231, SCaBER, A549) reflecting breast, bladder and lung cancer in vitro. Thus, our data suggest the substantial role of the ITIH5-specific VIT domain in ITIH5-mediated suppression of tumor cell proliferation. As extracellularly administered ITIH5 peptides mimic the growth-inhibitory effects of the full-length ITIH5 tumor suppressor protein, they may constitute the basis for developing anticancer drugs in the future.

Transcriptome analysis reveals the hepatoprotective mechanism of soybean meal peptides against alcohol-induced acute liver injury mice

This study aimed was to explore the hepatoprotective potential of soybean meal peptides (SPs) against alcohol-induced liver injury and investigate the underlying mechanisms through transcriptome analysis. The chemical antioxidant analysis of SPs exhibited potent ABTS radical scavenging capacity (11.94 ± 0.41 mg TE/100 mg peptide), ferric reducing antioxidant power (6.42 ± 0.32 mmol Fe2+/100 mg peptide), and oxygen radical absorption capacity (14.78 ± 0.01 mg TE/100 mg peptide). Moreover, SPs increased cell viability and reduced intracellular reactive oxygen species levels in Caco-2 cells by H2O2-induced, and without cytotoxicity. In the mice model, preintervention with SPs reduced the levels of aspartate transaminase/alanine transaminase, total cholesterol, triglyceride and malondialdehyde by alcohol-induced, meanwhile, increased the levels of total superoxide dismutase, glutathione and catalase by alcohol-induced. Histological analysis showed that SPs alleviated the liver injury by alcohol-induced and no toxic effects on the kidneys. According to transcriptome analysis, 1737 genes were significantly differentially expressed (1076 up-regulated and 661 down-regulated) after SPs pretreatment. The main functions of these genes were related to inflammation, lipid metabolism and oxidation. The findings from the present study suggested that SPs produced positive hepatoprotection and showed potential to be used as a dietary supplement or an ingredient of functional food.

N-Glycosylation of Lipocalin 2 Is Not Required for Secretion or Exosome Targeting

Lipocalin 2 (LCN2) is a highly conserved secreted adipokine acting as a serum transport protein for small hydrophobic molecules such as fatty acids and steroids. In addition, LCN2 limits bacterial growth by sequestering iron-containing siderophores and further protects against intestinal inflammation and tumorigenesis associated with alterations in the microbiota. Human LCN2 contains one N-glycosylation site conserved in other species. It was postulated that this post-translational modification could facilitate protein folding, protects from proteolysis, is required for proper trafficking from the Golgi apparatus to the cell surface, and might be relevant for effective secretion. We here show that the homologous nucleoside antibiotic tunicamycin blocks N-linked glycosylation but not secretion of LCN2 in primary murine hepatocytes, derivatives thereof, human lung carcinoma cell line A549, and human prostate cancer cell line PC-3. Moreover, both the glycosylated and the non-glycosylated LCN2 variants are equally targeted to exosomes, demonstrating that this post-translational modification is not necessary for proper trafficking of LCN2 into these membranous extracellular vesicles. Furthermore, a hydrophobic cluster analysis revealed that the N-glycosylation site is embedded in a highly hydrophobic evolutionarily conserved surrounding. In sum, our data indicate that the N-glycosylation of LCN2 is not required for proper secretion and exosome cargo recruitment in different cell types, but might be relevant to increase overall solubility.

Differential representation of liver proteins in obese human subjects suggests novel biomarkers and promising targets for drug development in obesity

The proteome of liver biopsies from human obese (O) subjects has been compared to those of nonobese (NO) subjects using two-dimensional gel electrophoresis (2-DE). Differentially represented proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS)-based peptide mass fingerprinting (PMF) and nanoflow-liquid chromatography coupled to electrospray-tandem mass spectrometry (nLC-ESI-MS/MS). Overall, 61 gene products common to all of the liver biopsies were identified within 65 spots, among which 25 ones were differently represented between O and NO subjects. In particular, over-representation of short-chain acyl-CoA dehydrogenase, Δ(3,5)-Δ(2,4)dienoyl-CoA isomerase, acetyl-CoA acetyltransferase, glyoxylate reductase/hydroxypyruvate reductase, fructose-biphosphate aldolase B, peroxiredoxin I, protein DJ-1, catalase, α- and β-hemoglobin subunits, 3-mercaptopyruvate S-transferase, calreticulin, aminoacylase 1, phenazine biosynthesis-like domain-containing protein and a form of fatty acid-binding protein, together with downrepresentation of glutamate dehydrogenase, glutathione S-transferase A1, S-adenosylmethionine synthase 1A and a form of apolipoprotein A-I, was associated with the obesity condition. Some of these metabolic enzymes and antioxidant proteins have already been identified as putative diagnostic markers of liver dysfunction in animal models of steatosis or obesity, suggesting additional investigations on their role in these syndromes. Their differential representation in human liver was suggestive of their consideration as obesity human biomarkers and for the development of novel antiobesity drugs.

Lipocalin 2 (LCN2) Expression in Hepatic Malfunction and Therapy

Lipocalin 2 (LCN2) is a secreted protein that belongs to the Lipocalins, a group of transporters of small lipophilic molecules such as steroids, lipopolysaccharides, iron, and fatty acids in circulation. Two decades after its discovery and after a high variety of published findings, LCN2's altered expression has been assigned to critical roles in several pathological organ conditions, including liver injury and steatosis, renal damage, brain injury, cardiomyopathies, muscle-skeletal disorders, lung infection, and cancer in several organs. The significance of this 25-kDa lipocalin molecule has been impressively increased during the last years. Data from several studies indicate the role of LCN2 in physiological conditions as well as in response to cellular stress and injury. LCN2 in the liver shows a protective role in acute and chronic injury models where its expression is highly elevated. Moreover, LCN2 expression is being considered as a potential strong biomarker for pathological conditions, including rheumatic diseases, cancer in human organs, hepatic steatosis, hepatic damage, and inflammation. In this review, we summarize experimental and clinical findings linking LCN2 to the pathogenesis of liver disease.

Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF.

METHODS

We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF.

RESULTS

Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001).

CONCLUSIONS

NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome.

LAY SUMMARY

Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF.

Pharmacological inhibition of apical sodium-dependent bile acid transporter changes bile composition and blocks progression of sclerosing cholangitis in multidrug resistance 2 knockout mice

Deficiency of multidrug resistance 2 (mdr2), a canalicular phospholipid floppase, leads to excretion of low-phospholipid "toxic" bile causing progressive cholestasis. We hypothesize that pharmacological inhibition of the ileal, apical sodium-dependent bile acid transporter (ASBT), blocks progression of sclerosing cholangitis in mdr2(-/-) mice. Thirty-day-old, female mdr2(-/-) mice were fed high-fat chow containing 0.006% SC-435, a minimally absorbed, potent inhibitor of ASBT, providing, on average, 11 mg/kg/day of compound. Bile acids (BAs) and phospholipids were measured by mass spectrometry. Compared with untreated mdr2(-/-) mice, SC-435 treatment for 14 days increased fecal BA excretion by 8-fold, lowered total BA concentration in liver by 65%, reduced total BA and individual hydrophobic BA concentrations in serum by >98%, and decreased plasma alanine aminotransferase, total bilirubin, and serum alkaline phosphatase levels by 86%, 93%, and 55%, respectively. Liver histology of sclerosing cholangitis improved, and extent of fibrosis decreased concomitant with reduction of hepatic profibrogenic gene expression. Biliary BA concentrations significantly decreased and phospholipids remained low and unchanged with treatment. The phosphatidylcholine (PC)/BA ratio in treated mice corrected toward a ratio of 0.28 found in wild-type mice, indicating decreased bile toxicity. Hepatic RNA sequencing studies revealed up-regulation of putative anti-inflammatory and antifibrogenic genes, including Ppara and Igf1, and down-regulation of several proinflammatory genes, including Ccl2 and Lcn2, implicated in leukocyte recruitment. Flow cytometric analysis revealed significant reduction of frequencies of hepatic CD11b(+) F4/80(+) Kupffer cells and CD11b(+) Gr1(+) neutrophils, accompanied by expansion of anti-inflammatory Ly6C(-) monocytes in treated mdr2(-/-) mice.

CONCLUSION

Inhibition of ASBT reduces BA pool size and retention of hydrophobic BA, favorably alters the biliary PC/BA ratio, profoundly changes the hepatic transcriptome, attenuates recruitment of leukocytes, and abrogates progression of murine sclerosing cholangitis.

From the periphery to the brain: Lipocalin-2, a friend or foe?

Lipocalin-2 (LCN2) is an acute-phase protein that, by binding to iron-loaded siderophores, acts as a potent bacteriostatic agent in the iron-depletion strategy of the immune system to control pathogens. The recent identification of a mammalian siderophore also suggests a physiological role for LCN2 in iron homeostasis, specifically in iron delivery to cells via a transferrin-independent mechanism. LCN2 participates, as well, in a variety of cellular processes, including cell proliferation, cell differentiation and apoptosis, and has been mostly found up-regulated in various tissues and under inflammatory states, being its expression regulated by several inducers. In the central nervous system less is known about the processes involving LCN2, namely by which cells it is produced/secreted, and its impact on cell proliferation and death, or in neuronal plasticity and behaviour. Importantly, LCN2 recently emerged as a potential clinical biomarker in multiple sclerosis and in ageing-related cognitive decline. Still, there are conflicting views on the role of LCN2 in pathophysiological processes, with some studies pointing to its neurodeleterious effects, while others indicate neuroprotection. Herein, these various perspectives are reviewed and a comprehensive and cohesive view of the general function of LCN2, particularly in the brain, is provided.

Lipopolysaccharide-induced inflammatory liver injury in mice

The intraperitoneal application of lipopolysaccharide (LPS) alone or in combination with other hepatotoxins is an experimental model for inducing systemic and hepatic inflammation in rodents applied worldwide. The endotoxin is recognized by the LPS-binding protein. This complex binds together with the lymphocyte antigen 96 (MD2) and the pattern-recognition receptor CD14 to members of the toll-like receptor family. The activated receptor complex in turn transduces signals to well characterized intracellular cascades that result in a multifaceted network of intracellular responses ending in inflammation. The most prominent among these is the activation of the NF-κB pathway and the production of a multitude of inflammatory cytokines. Although the application of LPS is in general easy to perform, unintended variations in preparation of the injection solution or in handling of the animals might affect the reproducibility or the outcome of a specific experiment. Here, we present a well-standardized protocol that allows for an induction of highly reproducible acute hepatic inflammation in mice. Furthermore, examples of appropriate readouts for the resulting inflammatory response are given.

The role of lipocalin-2 in liver regeneration

BACKGROUND & AIMS

Various immune mediators such as interleukin-6 (IL-6) have been implicated in the process of liver regeneration. Lipocalin-2 (LCN2) has been recently characterized as a prototypic immune mediator produced by various cell types being involved mainly in host defence. In addition, numerous studies have demonstrated its clinical value as a biomarker. This study aimed at defining the role of LCN2 in liver regeneration.

METHODS

We studied LCN2 expression in wild-type mice in a model of partial hepatectomy (PH). Furthermore, we evaluated liver regeneration after PH in LCN-deficient mice compared to littermate controls. Serum levels of LCN2 were assessed in a small group of patients undergoing hepatic resection.

RESULTS

LCN2 is dramatically induced in livers and sera of wild-type mice after PH, whereas liver LCN2-receptor expression was decreased. Sham operations did not affect hepatic and serum LCN2 expression. Although LCN2-deficient mice exhibited increased baseline liver expression indices, LCN2-deficient mice did not differ from wild-type mice with respect to hepatic proliferation suggesting that this molecule is not involved in hepatic repair. Only serum IL-1β levels were slightly lower in LCN(-/-) mice, whereas IL-6 serum levels did not differ between various tested animal groups. In humans undergoing hepatic resection, LCN2 levels increased significantly within 24 h following surgery.

CONCLUSIONS

LCN2, although massively induced in mice after PH, is not relevant in murine hepatic regeneration. Further, human studies have to define whether LCN2 could evolve as biomarker after liver surgery.

Bile duct ligation in mice: induction of inflammatory liver injury and fibrosis by obstructive cholestasis

In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well as to excrete bilirubin and other metabolic products. In the liver, the experimental obstruction of the extrahepatic biliary system initiates a complex cascade of pathological events that leads to cholestasis and inflammation resulting in a strong fibrotic reaction originating from the periportal fields. Therefore, surgical ligation of the common bile duct has become the most commonly used model to induce obstructive cholestatic injury in rodents and to study the molecular and cellular events that underlie these pathophysiological mechanisms induced by inappropriate bile flow. In recent years, different surgical techniques have been described that either allow reconnection or reanastomosis after bile duct ligation (BDL), e.g., partial BDL, or other microsurgical methods for specific research questions. However, the most frequently used model is the complete obstruction of the common bile duct that induces a strong fibrotic response after 21 to 28 days. The mortality rate can be high due to infectious complications or technical inaccuracies. Here we provide a detailed surgical procedure for the BDL model in mice that induce a highly reproducible fibrotic response in accordance to the 3R rule for animal welfare postulated by Russel and Burch in 1959.

Identification and validation of potential new biomarkers for prostate cancer diagnosis and prognosis using 2D-DIGE and MS

This study was designed to identify and validate potential new biomarkers for prostate cancer and to distinguish patients with and without biochemical relapse. Prostate tissue samples analyzed by 2D-DIGE (two-dimensional difference in gel electrophoresis) and mass spectrometry (MS) revealed downregulation of secernin-1 (P < 0.044) in prostate cancer, while vinculin showed significant upregulation (P < 0.001). Secernin-1 overexpression in prostate tissue was validated using Western blot and immunohistochemistry while vinculin expression was validated using immunohistochemistry. These findings indicate that secernin-1 and vinculin are potential new tissue biomarkers for prostate cancer diagnosis and prognosis, respectively. For validation, protein levels in urine were also examined by Western blot analysis. Urinary vinculin levels in prostate cancer patients were significantly higher than in urine from nontumor patients (P = 0.006). Using multiple reaction monitoring-MS (MRM-MS) analysis, prostatic acid phosphatase (PAP) showed significant higher levels in the urine of prostate cancer patients compared to controls (P = 0.012), while galectin-3 showed significant lower levels in the urine of prostate cancer patients with biochemical relapse, compared to those without relapse (P = 0.017). Three proteins were successfully differentiated between patients with and without prostate cancer and patients with and without relapse by using MRM. Thus, this technique shows promise for implementation as a noninvasive clinical diagnostic technique.

Simultaneous monitoring of cerebral metal accumulation in an experimental model of Wilson's disease by laser ablation inductively coupled plasma mass spectrometry

BACKGROUND

Neuropsychiatric affection involving extrapyramidal symptoms is a frequent component of Wilson's disease (WD). WD is caused by a genetic defect of the copper (Cu) efflux pump ATPase7B. Mouse strains with natural or engineered transgenic defects of the Atp7b gene have served as model of WD. These show a gradual accumulation and concentration of Cu in liver, kidneys, and brain. However, still little is known about the regional distribution of Cu inside the brain, its influence on other metals and subsequent pathophysiological mechanisms. We have applied laser ablation inductively coupled plasma mass spectrometry and performed comparative metal bio-imaging in brain sections of wild type and Atp7b null mice in the age range of 11-24 months. Messenger RNA and protein expression of a panel of inflammatory markers were assessed using RT-PCR and Western blots of brain homogenates.

RESULTS

We could confirm Cu accumulation in brain parenchyma by a factor of two in WD (5.5 μg g(-1) in the cortex) vs. controls (2.7 μg g(-1)) that was already fully established at 11 months. In the periventricular regions (PVR) known as structures of prominent Cu content, Cu was reduced in turn by a factor of 3. This corroborates the view of the PVR as efflux compartments with active transport of Cu into the cerebrospinal fluid. Furthermore, the gradient of Cu increasing downstream the PVR was relieved. Otherwise the architecture of Cu distribution was essentially maintained. Zinc (Zn) was increased by up to 40% especially in regions of high Cu but not in typical Zn accumulator regions, a side effect due to the fact that Zn is to some degree a substrate of Cu-ATPases. The concentrations of iron (Fe) and manganese (Mn) were constant throughout all regions assessed. Inflammatory markers TNF-α, TIMP-1 and the capillary proliferation marker α-SMA were increased by a factor of 2-3 in WD.

CONCLUSIONS

This study confirmed stable cerebral Cu accumulation in parenchyma and discovered reduced Cu in cerebrospinal fluid in Atp7b null mice underlining the diagnostic value of micro-local analytical techniques.

Metalloproteinase-9 and neutrophil gelatinase-associated lipocalin plasma and tissue levels evaluation in middle cerebral artery aneurysms

Background. Cerebral aneurysms are relatively common in adults, with a prevalence ranging between 1% and 5%. Subarachnoid hemorrhage, following aneurismal rupture, is a major cause of death and disability in these patients. Matrix Metalloproteinases (MMPs) and Neutrophil Gelatinase-Associated Lipocalin (NGAL) seem to be involved in the pathogenesis and in the clinical course of aneurysms. In this study, we evaluated the relationship between tissue and plasma levels of MMP-9 and NGAL in patient with ruptured and unruptured middle cerebral artery aneurysms. Methods. An open label study was conducted on 7 patients with middle cerebral aneurysms. Three patients had ruptured aneurysms (Group I) and four patients had unruptured aneurysms (Group II). All patients underwent aneurysm clipping. Plasma levels of MMP-9 and NGAL were evaluated through ELISA Test. During the surgery, biopsies of the aneurysmatic arteries were taken and frozen (- 80°C) for Western blot evaluation of MMPs and NGAL expression. Four healthy volunteers (Group III) represented the control group for ELISA testing. Results. Both plasma MMP-9 and NGAL levels were significantly high in aneurysmatic patients respect to those of control patients, and these levels were higher (P < 0.01) in patients with ruptured aneurysms respect to patients with unruptured aneurysms (P < 0.01). The latest findings were similarly evident in tissue evaluation of MMP-9 and NGAL between ruptured and unruptured aneurysms. Conclusion. This study suggests that MMP-9 and NGAL plasma levels may be useful to predict the clinical course of a cerebral aneurysms in order to evaluate the progression of the disease and the tendency of an aneurysm to rupture.

Experimental liver fibrosis research: update on animal models, legal issues and translational aspects

Liver fibrosis is defined as excessive extracellular matrix deposition and is based on complex interactions between matrix-producing hepatic stellate cells and an abundance of liver-resident and infiltrating cells. Investigation of these processes requires in vitro and in vivo experimental work in animals. However, the use of animals in translational research will be increasingly challenged, at least in countries of the European Union, because of the adoption of new animal welfare rules in 2013. These rules will create an urgent need for optimized standard operating procedures regarding animal experimentation and improved international communication in the liver fibrosis community. This review gives an update on current animal models, techniques and underlying pathomechanisms with the aim of fostering a critical discussion of the limitations and potential of up-to-date animal experimentation. We discuss potential complications in experimental liver fibrosis and provide examples of how the findings of studies in which these models are used can be translated to human disease and therapy. In this review, we want to motivate the international community to design more standardized animal models which might help to address the legally requested replacement, refinement and reduction of animals in fibrosis research.