Heme scavenging and the other facets of hemopexin

Hemopexin is an acute-phase plasma glycoprotein, produced mainly by the liver and released into plasma, where it binds heme with high affinity. Other sites of hemopexin synthesis are the nervous system, skeletal muscle, retina, and kidney. The only known receptor for the heme-hemopexin complex is the scavenger receptor, LDL receptor-related protein (LRP)1, which is expressed in most cell types, thus indicating multiple sites of heme-hemopexin complex recovery. The better-characterized function of hemopexin is heme scavenging at the systemic level, consisting of the transport of heme to the liver, where it is catabolyzed or used for the synthesis of hemoproteins or exported to bile canaliculi. This is important both in physiologic heme management for heme-iron recycling and in pathologic conditions associated with intravascular hemolysis to prevent the prooxidant and proinflammatory effects of heme. Other than scavenging heme, the heme-hemopexin complex has been shown to be able to activate signaling pathways, thus promoting cell survival, and to modulate gene expression. In this review, the importance of heme scavenging by hemopexin, as well as the other emerging functions of this protein, are discussed.

The mitochondrial heme exporter FLVCR1b mediates erythroid differentiation

Feline leukemia virus subgroup C receptor 1 (FLVCR1) is a cell membrane heme exporter that maintains the balance between heme levels and globin synthesis in erythroid precursors. It was previously shown that Flvcr1-null mice died in utero due to a failure of erythropoiesis. Here, we identify Flvcr1b, a mitochondrial Flvcr1 isoform that promotes heme efflux into the cytoplasm. Flvcr1b overexpression promoted heme synthesis and in vitro erythroid differentiation, whereas silencing of Flvcr1b caused mitochondrial heme accumulation and termination of erythroid differentiation. Furthermore, mice lacking the plasma membrane isoform (Flvcr1a) but expressing Flvcr1b had normal erythropoiesis, but exhibited hemorrhages, edema, and skeletal abnormalities. Thus, FLVCR1b regulates erythropoiesis by controlling mitochondrial heme efflux, whereas FLVCR1a expression is required to prevent hemorrhages and edema. The aberrant expression of Flvcr1 isoforms may play a role in the pathogenesis of disorders characterized by an imbalance between heme and globin synthesis.

Functional antagonism between Sall4 and Plzf defines germline progenitors

Transcription factors required for formation of embryonic tissues often maintain their expression in adult stem cell populations, but whether their function remains equivalent is not clear. Here we demonstrate critical and distinct roles for Sall4 in development of embryonic germ cells and differentiation of postnatal spermatogonial progenitor cells (SPCs). In differentiating SPCs, Sall4 levels transiently increase and Sall4 physically interacts with Plzf, a transcription factor exclusively required for adult stem cell maintenance. Mechanistically, Sall4 sequesters Plzf to noncognate chromatin domains to induce expression of Kit, a target of Plzf-mediated repression required for differentiation. Plzf in turn antagonizes Sall4 function by displacing Sall4 from cognate chromatin to induce Sall1 expression. Taken together, these data suggest that transcription factors required for embryonic tissue development postnatally take on distinct roles through interaction with opposing factors, which hence define properties of the adult stem cell compartment.

Enhanced splenomegaly and severe liver inflammation in haptoglobin/hemopexin double-null mice after acute hemolysis

Intravascular hemolysis is associated with several pathologic conditions that include hemoglobinopathies, trauma, malaria, and bacterial infections. Among plasma-protective proteins against oxidative damage caused by red blood cell rupture, haptoglobin and hemopexin are thought to play a crucial role. Haptoglobin and hemopexin, by binding with high-affinity hemoglobin and heme, respectively, exert an antioxidant action by preventing heme-catalyzed free radical production. Moreover, these proteins prevent iron loss by inhibiting glomerular filtration of hemoglobin and heme diffusion through plasma membranes. Analysis of single-null mice demonstrated the antioxidant action of haptoglobin and hemopexin in vivo and suggests that the 2 proteins cooperate in the resolution of hemolytic stress. To evaluate the physiological relevance of the haptoglobin-hemopexin system and the principal targets of its action, we generated haptoglobin-hemopexin double-knockout mice and analyzed them under basal conditions and after acute hemolysis. Whereas haptoglobin-hemopexin double-null mice displayed no obvious alteration in phenotype under basal conditions, nonlethal hemolytic stress in these animals led to pronounced splenomegaly as well as liver inflammation and fibrosis. These data demonstrate that haptoglobin and hemopexin together are essential for protection from splenomegaly and liver fibrosis resulting from intravascular hemolysis.

Acylated and unacylated ghrelin impair skeletal muscle atrophy in mice

Cachexia is a wasting syndrome associated with cancer, AIDS, multiple sclerosis, and several other disease states. It is characterized by weight loss, fatigue, loss of appetite, and skeletal muscle atrophy and is associated with poor patient prognosis, making it an important treatment target. Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy balance through binding to the receptor GHSR-1a. Only acylated ghrelin (AG), but not the unacylated form (UnAG), can bind GHSR-1a; however, UnAG and AG share several GHSR-1a-independent biological activities. Here we investigated whether UnAG and AG could protect against skeletal muscle atrophy in a GHSR-1a-independent manner. We found that both AG and UnAG inhibited dexamethasone-induced skeletal muscle atrophy and atrogene expression through PI3Kβ-, mTORC2-, and p38-mediated pathways in myotubes. Upregulation of circulating UnAG in mice impaired skeletal muscle atrophy induced by either fasting or denervation without stimulating muscle hypertrophy and GHSR-1a-mediated activation of the GH/IGF-1 axis. In Ghsr-deficient mice, both AG and UnAG induced phosphorylation of Akt in skeletal muscle and impaired fasting-induced atrophy. These results demonstrate that AG and UnAG act on a common, unidentified receptor to block skeletal muscle atrophy in a GH-independent manner.

History of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal mucosa and unknown etiology. In this review, we identified three main eras in the IBD history. Between the 19th and the 20th century, the primary task had been the definition of the diagnostic criteria in order to differentiate the new entity from intestinal tuberculosis. In the 20th century, an intense and prolific therapeutic research prevailed, culminating in the introduction of biological drugs in the clinical setting. Since the beginning of the 21st century, traditional definition criteria have been challenged by holistic criteria in an effort to seek a still unattained cure. Centuries of worldwide efforts on IBD etiology and therapy search have culminated in this novel strategy.

Endoscopic mucosal resection for early colorectal neoplasia: pathologic basis, procedures, and outcomes

Open access endoscopy and screening programs enable detection and removal of an increased number of colon polyps in the early stages of neoplastic transformation. Unfortunately, polyps larger than 3 cm, involving more than one-third of circumference or two haustral folds, or with a flat/depressed morphology are more challenging to remove with standard polypectomy techniques. Endoscopic mucosal resection potentiates the removal, in a minimally invasive way, of certain colonic lesions that would otherwise require surgical or ablative treatment. Because the plane of resection during endoscopic mucosal resection is typically the middle to deep submucosal layer, compared with standard polypectomy, which normally provides resection at a mucosal level, endoscopic mucosal resection offers the advantage of providing en bloc resection specimens for histopathologic analysis. Indications to perform endoscopic mucosal resection are adenoma and small, well-differentiated carcinoma, confined to the mucosa or with minimal invasion to submucosa, and without any invasion to lymphatic channels or vessels. The most frequently reported major complications, such as perforation (0-5%) and bleeding (0.5-6%), may be controlled by endoscopic methods and rarely require surgical treatment. Follow-up postendoscopic mucosal resection is essential because of the risk of neoplastic recurrence.

Plasma protein haptoglobin modulates renal iron loading

Haptoglobin is the plasma protein with the highest binding affinity for hemoglobin. The strength of hemoglobin binding and the existence of a specific receptor for the haptoglobin-hemoglobin complex in the monocyte/macrophage system clearly suggest that haptoglobin may have a crucial role in heme-iron recovery. We used haptoglobin-null mice to evaluate the impact of haptoglobin gene inactivation on iron metabolism. Haptoglobin deficiency led to increased deposition of hemoglobin in proximal tubules of the kidney instead of the liver and the spleen as occurred in wild-type mice. This difference in organ distribution of hemoglobin in haptoglobin-deficient mice resulted in abnormal iron deposits in proximal tubules during aging. Moreover, iron also accumulated in proximal tubules after renal ischemia-reperfusion injury or after an acute plasma heme-protein overload caused by muscle injury, without affecting morphological and functional parameters of renal damage. These data demonstrate that haptoglobin crucially prevents glomerular filtration of hemoglobin and, consequently, renal iron loading during aging and following acute plasma heme-protein overload.

Helicobacter species sequences in liver samples from patients with and without hepatocellular carcinoma

AIM

Only a minority of patients carrying a defined viral aetiologic agent develop cirrhosis and ultimately hepatocellular carcinoma (HCC), the mechanism underlying the worsening is still undefined. Experimental infection by Helicobacter hepaticus in mice causes chronic hepatitis and HCC and recently, more Helicobacter species (Helicobacter spp.) have been detected in the liver of patients suffering from cholestatic diseases and HCC arising from non-cirrhotic liver. We investigated whether Helicobacter spp. sequences could be detected in the liver of patients with cirrhosis and HCC compared to subjects with metastasis to liver from colon cancer.

METHODS

Twenty-three liver samples from patients operated upon for HCC superimposed on hepatitis C virus (HCV)-related cirrhosis and 6 from patients with resected metastases from colorectal cancer, were tested by polymerase chain reaction for presence of genomic 16S rRNA of Helicobacter genus using specific primers. DNA sequencing and cag A gene analysis were also performed.

RESULTS

Genomic sequences of Helicobacter spp. were found in 17 of 20 (85%) liver samples from patients with HCC and in 2 of 6 samples from patients with liver metastasis. In three samples of the first group the result was uncertain. H pylori was revealed in 16 out of 17 positive samples and Helicobacter pullorum in the other.

CONCLUSION

Helicobacter spp., carcinogenic in mice, were found at a higher frequency in the liver of patients with HCV-related cirrhosis and HCC than those in patients without primary liver disease.

Helicobacter pylori: molecular basis for colonization and survival in gastric environment and resistance to antibiotics. A short review

Helicobacter pylori is a human-specific pathogen with a strict tropism for the gastric mucosa. This bacterium infects around half of the world population and is the main responsible for gastritis, peptic ulcer and, in some cases, for the pathogenesis of gastric cancer. Nevertheless, disease development in infected subjects depends not only on the bacterium, but also on the host genetic predisposition and on environmental factors. The fascinating question of how the bacterium can survive in the gastric environment has stimulated research in this field. It is now clear that H. pylori is able to colonize and adhere to the gastric epithelium through several mechanisms, including the breakdown of urea with production of the cell-toxic ammonia. The resulting raise in pH neutralizes acidity of the stomach, thereby allowing the bacterium to safely cross the mucus layer to the epithelial surface. Current challenges regard understanding the mechanisms of antibiotic resistance and how to overcome it. Lately, an increasing H. pylori resistance rate to antibiotics has been reported and several molecular bases for this phenomenon described. In this review, we highlight the current knowledge on mechanisms supporting H. pylori resistance to gastric environment and to therapy.

Stem cell-derived exosomes for wound healing: current status and promising directions

Wound healing, especially of chronic wounds, is still an unmet therapeutic area since assessment and management are extremely complicated. Although many efforts have been made to treat wounds, all strategies have achieved limited results for chronic wounds. Stem cell-based therapy is considered a promising approach for complex wounds such as those occurring in diabetics. Mesenchymal stem cell transplantation significantly improves wound closure, angiogenesis and wound healing. However, cell therapy is complex, expensive and time-consuming. Recent studies have shown that stem cell-derived exosomes can be an exciting approach to treat wounds. Exosomes derived from mesenchymal stem cells can induce benefit in almost all stages of wound healing, including control of immune responses, inhibition of inflammation, promoting cell proliferation and angiogenesis, while reducing scar formation during the wound healing process. This review aimed at offering an updated overview of the use of exosomes in biological applications, such as wound healing, and addresses not only current applications but also new directions for this next-generation approach in wound healing.

Recent advances in the treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder which presents with abdominal pain and altered bowel habits. It affects about 20% of the general population, mainly women, and has a considerable impact on the quality of life and health care costs. Four different entities of IBS have been identified: IBS with constipation (IBS‑ C), IBS with diarrhea (IBS D), IBS with a mixed pattern of constipation and diarrhea, and unclassified IBS. Although the precise pathogenesis of IBS remains unclear, its multifactorial nature is evident and includes environmental and host factors. Management of patients with this disease is challenging and a personalized approach is required. A strong, reassuring physician‑ patient relationship is crucial, followed by patient education, dietary advice, and stress reduction. For nonresponding patients, the therapeutic approach may include nonpharmacological therapies and / or pharmacotherapy. The choice of pharmacological treatment is based on the predominant symptom and a prespecified time point should be planned for effectiveness evaluation and dose adjustment. In patients with IBS‑ D, the therapeutic options include mainly antibiotics, such as rifaximin, peripheral opioid agonists, mixed opioid agonists / antagonists, bile acid sequestrants, and antagonists of serotonin 5‑ hydroxytryptamine type 3 receptors. Bulking agents and osmotic laxatives represent the first line therapy for IBS‑ C, while lubiprostone and linaclotide should be reserved for difficult to treat patients. The involvement of gastrointestinal microbiota constitutes a fascinating field of exploration as it offers the potential to be modulated by the use of probiotics, prebiotics, synbiotics as well as fecal microbiota transplantation. This review offers an updated overview on the recent advances in the treatment of IBS.

The RNA-binding protein ESRP1 promotes human colorectal cancer progression

Epithelial splicing regulatory protein 1 (ESRP1) is an epithelial cell-specific RNA binding protein that controls several key cellular processes, like alternative splicing and translation. Previous studies have demonstrated a tumor suppressor role for this protein. Recently, however, a pro-metastatic function of ESRP1 has been reported. We thus aimed at clarifying the role of ESRP1 in Colorectal Cancer (CRC) by performing loss- and gain-of-function studies, and evaluating tumorigenesis and malignancy with in vitro and in vivo approaches. We found that ESRP1 plays a role in anchorage-independent growth of CRC cells. ESRP1-overexpressing cells grown in suspension showed enhanced fibroblast growth factor receptor (FGFR1/2) signalling, Akt activation, and Snail upregulation. Moreover, ESRP1 promoted the ability of CRC cells to generate macrometastases in mice livers. High ESRP1 expression may thus stimulate growth of cancer epithelial cells and promote colorectal cancer progression. Our findings provide mechanistic insights into a previously unreported, pro-oncogenic role for ESRP1 in CRC, and suggest that fine-tuning the level of this RNA-binding protein could be relevant in modulating tumor growth in a subset of CRC patients.

Liver fibrosis: the 2017 state of art

Liver fibrosis is a wound-healing response to a wide spectrum of chronic liver injuries. It is characterized by loss of hepatocytes and alteration in hepatic architecture following an imbalance between extracellular matrix synthesis and degradation. Irrespectively of underlying etiology, fibrosis may progress to cirrhosis and specific pathogenetic mechanisms as well as different disease patterns may be identified according to etiology. Liver biopsy is still considered the gold standard for fibrosis assessment, despite the fact that it is invasive, has poor patient compliance and is not exempt of complications. Several reliable and non-invasive tools are currently used in clinical practice, including imaging methods and surrogate serum biomarkers, commonly combined into composite scores. The main limitation of non-invasive methods is the low performance in the discrimination of intermediate stages of fibrosis. However, with the recent availability of novel treatment options, particularly for chronic hepatitis C, a precise staging of liver fibrosis is becoming clinically less relevant. Conversely, since patients with cirrhosis need to be monitored for the risk of hepatocellular carcinoma development, the accurate detection of this condition is a primary endpoint. Finally, several promising antifibrotic agents are under investigation in phase I and II trials. Nevertheless, further efforts are needed for the identification of novel potential targets for the development of antifibrotic drugs able to arrest, and possibly revert liver fibrogenesis.

Helicobacters and extragastric diseases

For two decades, Helicobacter pylori has been considered as the culprit in many extragastric manifestations. However, for several of these supposed associations the hypothesis of an etiological role has not yet been fully investigated. This may be due to a series of factors linked to the epidemiological features of the studies and to the diseases investigated. This review attempts to highlight the main reported associations of H. pylori with extragastric manifestations during the last year. The most convincing data arise in the field of idiopathic thrombocytopenic purpura (ITP) and sideropenic anemia. Long-term follow-up studies have shown that 50% of subjects with ITP maintain a hematological response after H. pylori eradication. There is also growing evidence of the role of H. pylori in other diseases, including ischemic heart disease even though results are not conclusive.

Helicobacter pylori seroprevalence in patients with cirrhosis of the liver and hepatocellular carcinoma

BACKGROUND

Infection by Helicobacter hepaticus causes chronic hepatitis and hepatocellular carcinoma (HCC) in mice, and Helicobacter pylori (H. pylori) genomic sequences have been demonstrated in the liver of patients with HCC. H. pylori infection reportedly occurs with high frequency in patients with cirrhosis but none of the studies has investigated it in subjects with cirrhosis and superimposed HCC. In this case-control study, we searched for the seroprevalence of H. pylori infection in patients with HCC.

PATIENTS AND METHOD

Forty-six patients (30 males, 16 females, mean age 69 years) with HCC and hepatitis C virus (HCV)-related cirrhosis were compared to 46 sex and age (+/-1 year) matched patients presenting consecutively to the Emergency Department of Molinette Hospital of Torino. All subjects were tested for presence in serum of IgG antibodies against H. pylori and the result was analyzed using the chi-square test.

RESULTS

H. pylori seropositivity was more prevalent among patients with HCC (36/46, 78.2%) than in controls (25/46, 54%) (P<0.05) (OR 3.02, 95% confidence interval ). Twenty-five out of 30 (83.3%) male patients showed seropositivity at a variance with 16/30 (53%) in the controls (P<0.05); 11 out of 16 (68.7%) female patients were seropositive versus 9 out of 16 (56.2%) control subjects (P=n.s.).

CONCLUSION

Seroprevalence of antibodies to H. pylori was found to be higher in patients with HCC than in controls.

Etiology of chronic liver diseases in the Northwest of Italy, 1998 through 2014

AIM

To assess the etiology of chronic liver diseases (CLD) from 1998 to 2014 at the outpatient clinic of Gastroenterology of the main hospital in Northwest of Italy among those dedicated to hepatology.

METHODS

A random sample of charts of patients referred to for increased liver enzymes between January 1998 and December 2006, and between January 2012 and December 2014 were reviewed. Etiology search included testing for hepatitis B virus (HBV), hepatitis C virus (HCV), autoimmune hepatitis, primary biliary cirrhosis, Wilson's disease and hereditary hemocromatosis. A risky alcohol consumption was also considered. Non-alcoholic fatty liver disease (NAFLD) was diagnosed in patients with histological and/or ultrasound evidence of steatosis/steatohepatitis, and without other causes of CLD.

RESULTS

The number of patients included was 1163. Of them, 528 (45%) had positivity for HCV and 85 (7%) for HBV. Among the virus-free patients, 417 (36%) had metabolic disorders whereas the remaining had history of alcohol abuse, less prevalent causes of CLD or concomitant conditions. In comparison to 1998-2000 (41%), a reduction of HCV alone-related cases was detected during the periods 2001-2003 (35%, OR = 0.75, 95%CI: 0.53-1.06), 2004-2006 (33%, OR = 0.70, 95%CI: 0.50-0.97) and 2012-2014 (31%, OR = 0.64, 95%CI: 0.46-0.91). On the contrary, in comparison to 1998-2000 (31%), metabolic-alone disorders increased in the period 2004-2006 (39%, OR = 1.37, 95%CI: 0.99-1.91) and 2012-2014 (41%, OR = 1.53, 95%CI: 1.09-2.16). The other etiologies remained stable. The increase of incidence of metabolic-alone etiology during the period 2004-2006 and 2012-2014 tended to be higher in older patients (≥ 50 years) compared to younger (P = 0.058).

CONCLUSION

In the Northwest of Italy, during this study period, the prevalence of HCV infection decreased notably whereas that of NAFLD increased.

Rifabutin-Based Rescue Therapy for Helicobacter pylori Eradication: A Long-Term Prospective Study in a Large Cohort of Difficult-to-Treat Patients

The most commonly used regimens fail to eradicate Helicobacter pylori (H. pylori) infection in 5⁻10% of patients. Those not cured with treatments based on amoxicillin, clarithromycin, nitroimidazoles, fluoroquinolones, bismuth or tetracycline have no other conventional options thereafter. In this prospective long-term monocentric study, patients who failed to eradicate H. pylori following treatment with all conventional antibiotics were included. All subjects were treated with rifabutin 150 mg, amoxicillin 1 g and a standard dose of proton pump inhibitor, twice daily for 14 days. A negative 13C-urea breath test was used four weeks after treatment completion as an index of H. pylori eradication. Three hundred and two patients were included. Fifty-four percent (164/302) had peptic ulcer disease while 45.7% (138/302) had gastritis or functional dyspepsia. Per-protocol eradication and intention-to-treat eradication were achieved in 72.7% and 71.5%, respectively. A univariate analysis showed that gender, ethnic background, smoking habits and familial history of gastric diseases were not predictive factors of response, while with multiple logistic regression analysis, the ethnic background (Italian) predicted a poor response in the second period of the study (2010⁻2017). In conclusion, this study on a large cohort of very difficult-to-treat patients showed that rifabutin-based rescue therapy is an acceptable and safe strategy after multiple eradication failures with conventional antibiotics.

On-Treatment Decrease of Serum Interleukin-6 as a Predictor of Clinical Response to Biologic Therapy in Patients with Inflammatory Bowel Diseases

In patients with inflammatory bowel diseases (IBD) undergoing biologic therapy, biomarkers of treatment response are still scarce. This study aimed to evaluate whether serum zonulin, a biomarker of intestinal permeability; soluble CD163 (sCD163), a macrophage activation marker; and a panel of serum cytokines could predict the response to biologic treatment in patients with IBD. For this purpose, we prospectively enrolled 101 patients with IBD and 19 patients with irritable bowel syndrome (IBS) as a control group; 60 out of 101 patients underwent treatment with biologics. Zonulin, sCD163, and cytokines were measured at the baseline in all patients and after 10 weeks of treatment in the 60 patients who underwent biologic therapy. We observed that zonulin levels were higher in IBD patients with active disease compared to those in remission (p = 0.035), and that sCD163 values were higher in patients with IBD compared to those with IBS (p = 0.042), but no association with therapy response was observed for either biomarker. Conversely, interleukin (IL)-6, IL-8, IL-10, and tumor necrosis factor-alpha showed a significant reduction from baseline to week 10 of treatment, particularly in responder patients. By multivariate logistic regression analysis corrected for disease (Crohn's disease or ulcerative colitis), type of biologic drug (Infliximab, Adalimumab, Vedolizumab, or Ustekinumab) and disease activity, the reduction in IL-6 values was associated with a clinical response at 12 months of biological therapy (odds ratio (OR) = 4.75, 95% confidence interval (CI) 1.25-18.02, p = 0.022). In conclusion, the measurement of serum IL-6 in biologics-treated IBD patients may allow for the prediction of response to treatment at 12 months of therapy and thus may help with tailoring personalized treatment strategies.

The RNA binding protein ESRP1 fine-tunes the expression of pluripotency-related factors in mouse embryonic stem cells

In pluripotent stem cells, there is increasing evidence for crosstalk between post-transcriptional and transcriptional networks, offering multifold steps at which pluripotency can be controlled. In addition to well-studied transcription factors, chromatin modifiers and miRNAs, RNA-binding proteins are emerging as fundamental players in pluripotency regulation. Here, we report a new role for the RNA-binding protein ESRP1 in the control of pluripotency. Knockdown of Esrp1 in mouse embryonic stem cells induces, other than the well-documented epithelial to mesenchymal-like state, also an increase in expression of the core transcription factors Oct4, Nanog and Sox2, thereby enhancing self-renewal of these cells. Esrp1-depleted embryonic stem cells displayed impaired early differentiation in vitro and formed larger teratomas in vivo when compared to control embryonic stem cells. We also show that ESRP1 binds to Oct4 and Sox2 mRNAs and decreases their polysomal loading. ESRP1 thus acts as a physiological regulator of the finely-tuned balance between self-renewal and commitment to a restricted developmental fate. Importantly, both mouse and human epithelial stem cells highly express ESRP1, pinpointing the importance of this RNA-binding protein in stem cell biology.

Haemopexin affects iron distribution and ferritin expression in mouse brain

Haemopexin (Hx) is an acute phase plasma glycoprotein, mainly produced by the liver and released into plasma where it binds heme with high affinity and delivers it to the liver. This system provides protection against free heme-mediated oxidative stress, limits access by pathogens to heme and contributes to iron homeostasis by recycling heme iron. Hx protein has been found in the sciatic nerve, skeletal muscle, retina, brain and cerebrospinal fluid (CSF). Recently, a comparative proteomic analysis has shown an increase of Hx in CSF from patients with Alzheimer's disease, thus suggesting its involvement in heme detoxification in brain. Here, we report that Hx is synthesised in brain by the ventricular ependymal cells. To verify whether Hx is involved in heme scavenging in brain, and consequently, in the control of iron level, iron deposits and ferritin expression were analysed in cerebral regions known for iron accumulation. We show a twofold increase in the number of iron-loaded oligodendrocytes in the basal ganglia and thalamus of Hx-null mice compared to wild-type controls. Interestingly, there was no increase in H- and L-ferritin expression in these regions. This condition is common to several human neurological disorders such as Alzheimer's disease and Parkinson's disease in which iron loading is not associated with an adequate increase in ferritin expression. However, a strong reduction in the number of ferritin-positive cells was observed in the cerebral cortex of Hx-null animals. Consistent with increased iron deposits and inadequate ferritin expression, malondialdehyde level and Cu-Zn superoxide dismutase-1 expression were higher in the brain of Hx-null mice than in that of wild-type controls. These data demonstrate that Hx plays an important role in controlling iron distribution within brain, thus suggesting its involvement in iron-related neurodegenerative diseases.

Alcoholic liver fibrosis: detection and treatment

Alcohol consumption is one of the main risks to public health. Alcohol use disorders (AUDs) cause 80% of hepatotoxic deaths, and approximately 50% of cirrhosis is alcohol-related. The acceptable daily intake (ADI) for ethanol is 2.6 g/day, deduced from morbidity and mortality rates due to liver fibrosis. The relative risk of cirrhosis increases significantly for doses above 60 g/day for men and 20 g/day for women over a period of around 10 years. Twenty to 40% of steatosis cases will evolve into steatohepatitis/steatofibrosis, and 8 to 20% will evolve directly into liver cirrhosis. About 20 to 40% of steatohepatitis cases will evolve into cirrhosis, and 4 to 5% into hepatocellular carcinoma. This cascade of events evolves in 5 to 40 years, with the temporal variability caused by the subjects' genetic patterns and associated risk/comorbidity factors. Steatohepatitis should be considered "the rate limiting step:" usually, it can be resolved through abstinence, although for some patients, once this situation develops, it is not substantially modified by abstention and there is a risk of fibrotic evolution. Early detection of fibrosis, obtained by hepatic elastography, is a crucial step in patients with AUDs. Such strategy allows patients to be included in a detoxification program in order to achieve abstention. Drugs such as silybin, metadoxine, and adenosylmethionine can be used. Other drugs, with promising antifibrotic effects, are currently under study. In this review, we discuss clinical and pathogenetic aspects of alcohol-related liver fibrosis and present and future strategies to prevent cirrhosis.

Haptoglobin modifies the hemochromatosis phenotype in mice

Classic hereditary hemochromatosis (HH) is a common genetic disorder of iron metabolism caused by a mutation in the HFE gene. Whereas the prevalence of the mutation is very high, the clinical penetrance of the disease is low, suggesting that the HFE mutation is a necessary but not sufficient cause of clinical HH. Several candidate modifier genes have been proposed in mice and humans, including haptoglobin. Haptoglobin is the plasma protein with the highest binding affinity for hemoglobin. It delivers free plasma hemoglobin to the reticuloendothelial system, thus reducing loss of hemoglobin through the glomeruli and allowing heme-iron recycling. To gain insight into the role of haptoglobin as a modifier gene in HH, we used Hfe and haptoglobin double-null mice. Here, we show that Hfe and haptoglobin compound mutant mice accumulate significantly less hepatic iron than Hfe-null mice, thus demonstrating that haptoglobin-mediated heme-iron recovery may contribute significantly to iron loading in HH.

Oncogenic ALK regulates EMT in non-small cell lung carcinoma through repression of the epithelial splicing regulatory protein 1

A subset of Non-Small Cell Lung Carcinoma (NSCLC) carries chromosomal rearrangements involving the Anaplastic Lymphoma Kinase (ALK) gene. ALK-rearranged NSCLC are typically adenocarcinoma characterized by a solid signet-ring cell pattern that is frequently associated with a metastatic phenotype. Recent reports linked the presence of ALK rearrangement to an epithelial-mesenchymal transition (EMT) phenotype in NSCLC, but the extent and the mechanisms of an ALK-mediated EMT in ALK-rearranged NSCLC are largely unknown. We found that the ALK-rearranged H2228 and DFCI032, but not the H3122, cell lines displayed a mesenchymal phenotype. In these cell lines, oncogenic ALK activity dictated an EMT phenotype by directly suppressing E-cadherin and up-regulating vimentin expression, as well as expression of other genes involved in EMT. We found that the epithelial splicing regulatory protein 1 (ESRP1), a key regulator of the splicing switch during EMT, was repressed by EML4-ALK activity. The treatment of NSCLC cells with ALK tyrosine kinase inhibitors (TKIs) led to up-regulation of ESRP1 and E-cadherin, thus reverting the phenotype from mesenchymal to epithelial (MET). Consistently, ESRP1 knock-down impaired E-cadherin up-regulation upon ALK inhibition, whereas enforced expression of ESRP1 was sufficient to increase E-cadherin expression. These findings demonstrate an ALK oncogenic activity in the regulation of an EMT phenotype in a subset of NSCLC with potential implications for the biology of ALK-rearranged NSCLC in terms of metastatic propensity and resistance to therapy.