Meconium aspiration syndrome: from pathophysiology to treatment.

Meconium aspiration syndrome (MAS) is a clinical condition characterized by respiratory distress in neonates born through meconium-stained amniotic fluid (MSAF). Despite advances in obstetric practices and perinatal care, MAS remains an important cause of morbidity and mortality in term and post-term newborns. Since the 1960s, there have been significant changes in the perinatal and postnatal management of infants born through MSAF. Routine endotracheal suctioning is no longer recommended in both vigorous and non-vigorous neonates with MSAF. Supportive care along with new treatments such as surfactant, inhaled nitric oxide, and high-frequency ventilation has significantly improved the outcome of MAS patients. However, determining the most appropriate approach for this condition continues to be a topic of debate. This review offers an updated overview of the epidemiology, etiopathogenesis, diagnosis, management, and prognosis of infants with MAS.

Physiological and ultrastructural effects of acute ozone fumigation in the lichen Xanthoria parietina: the role of parietin and hydration state.

The physiological and ultrastructural effects induced by acute exposure to ozone (O3) were investigated in the lichen Xanthoria parietina. Our working hypothesis was that parietin content and hydration of the thalli may play a role in the modulation of the effects of O3 exposure. Four batches of X. parietina samples, dry and wet, with (P+) and without (P-) parietin, were fumigated for 1 h with 3 ppm O3. The effects of O3 were assessed immediately after the fumigation and after one week of recovery under controlled conditions. O3 fumigation caused physiological and ultrastructural impairment both to the photobiont and the mycobiont, irrespective if samples were fumigated wet or dry, and P+ or P-. However, one week after fumigation, a recovery was observed in P+ samples for the photobiont and in dry samples for the mycobiont. We suggest that the hydration state may play a major role in determining the severity of the damage, while the presence of parietin may promote the recovery. Our results provide physiological and ultrastructural basis to explain the ecological insensitivity of lichens to high environmental levels of ozone occurring during dry Mediterranean summers.

Focal adhesion kinase depletion reduces human hepatocellular carcinoma growth by repressing enhancer of zeste homolog 2.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer in humans. The focal adhesion tyrosine kinase (FAK) is often over-expressed in human HCC and FAK inhibition may reduce HCC cell invasiveness. However, the anti-oncogenic effect of FAK knockdown in HCC cells remains to be clarified. We found that FAK depletion in HCC cells reduced in vitro and in vivo tumorigenicity, by inducing G2/M arrest and apoptosis, decreasing anchorage-independent growth, and modulating the expression of several cancer-related genes. Among these genes, we showed that FAK silencing decreased transcription and nuclear localization of enhancer of zeste homolog 2 (EZH2) and its tri-methylation activity on lysine 27 of histone H3 (H3K27me3). Accordingly, FAK, EZH2 and H3K27me3 were concomitantly upregulated in human HCCs compared to non-tumor livers. In vitro experiments demonstrated that FAK affected EZH2 expression and function by modulating, at least in part, p53 and E2F2/3 transcriptional activity. Moreover, FAK silencing downregulated both EZH2 binding and histone H3K27me3 levels at the promoter of its target gene NOTCH2. Finally, we found that pharmacological inhibition of FAK activity resembled these effects although milder. In summary, we demonstrate that FAK depletion reduces HCC cell growth by affecting cancer-promoting genes including the pro-oncogene EZH2. Furthermore, we unveil a novel unprecedented FAK/EZH2 crosstalk in HCC cells, thus identifying a targetable network paving the way for new anticancer therapies.

Human B-cell memory is shaped by age- and tissue-specific T-independent and GC-dependent events.

Switched and IgM memory B cells execute different and noninterchangeable functions. We studied memory B cells in children of different ages, in peripheral blood and spleen and compared them with those of children born asplenic or unable to build germinal centers. We show that, whereas switched memory B cells are mostly generated in the germinal centers at all ages, IgM memory B cells can be distinct in three types with different developmental history. Innate IgM memory B cells, the largest pool in infants, are generated in the spleen by a germinal center-independent mechanism. With age, if the spleen is present and germinal centers are functional, innate IgM memory B cells are remodelled and accumulate somatic mutations. The third type of IgM memory B cell is a by-product of the germinal center reaction. Our data suggest that the B-cell memory developmental program is implemented during the first 5-6 years of life.

LPS-induced TNF-α factor mediates pro-inflammatory and pro-fibrogenic pattern in non-alcoholic fatty liver disease.

Lipopolysaccharide (LPS) is currently considered one of the major players in non-alcoholic fatty liver disease (NAFLD) pathogenesis and progression. Here, we aim to investigate the possible role of LPS-induced TNF-α factor (LITAF) in inducing a pro-inflammatory and pro-fibrogenic phenotype of non-alcoholic steatohepatitis (NASH).We found that children with NAFLD displayed, in different liver-resident cells, an increased expression of LITAF which correlated with histological traits of hepatic inflammation and fibrosis. Total and nuclear LITAF expression increased in mouse and human hepatic stellate cells (HSCs). Moreover, LPS induced LITAF-dependent transcription of IL-1ß, IL-6 and TNF-α in the clonal myofibroblastic HSC LX-2 cell line, and this effect was hampered by LITAF silencing. We showed, for the first time in HSCs, that LITAF recruitment to these cytokine promoters is LPS dependent. However, preventing LITAF nuclear translocation by p38MAPK inhibitor, the expression of IL-6 and TNF-α was significantly reduced with the aid of p65NF-ĸB, while IL-1ß transcription exclusively required LITAF expression/activity. Finally, IL-1ß levels in plasma mirrored those in the liver and correlated with LPS levels and LITAF-positive HSCs in children with NASH.In conclusion, a more severe histological profile in paediatric NAFLD is associated with LITAF over-expression in HSCs, which in turn correlates with hepatic and circulating IL-1ß levels outlining a panel of potential biomarkers of NASH-related liver damage. The in vitro study highlights the role of LITAF as a key regulator of the LPS-induced pro-inflammatory pattern in HSCs and suggests p38MAPK inhibitors as a possible therapeutic approach against hepatic inflammation in NASH.

Increased serum IgM, immunodeficiency, and autoimmunity: A clinical series.

BACKGROUND: Primary immunodeficiencies (PIDs) are generally characterized by recurrent infections; however they may be complicated by other clinical disorders such as allergy, autoimmunity, and lymphoproliferation. In particular, autoimmunity may be the first manifestation of the disease in patients with low serum immunoglobulins (Ig) levels. Here we describe a group of patients that share features of immunodeficiency and autoimmunity. MATERIALS AND METHODS: All patients went through a complete T and B cell subset characterization and a B cell function analysis in the peripheral blood by flow-cytometry. B cell proliferation and plasma cell differentiation was measured, in vitro, after CpG stimulation for 7 days as previously described. Semi-quantitative PCR analysis for AID and UNG expression as well as serum levels of BAFF were carried out in order to better define the diagnosis. RESULTS: Immunological and molecular analysis did not lead to the identification of known molecular defect typical of Hyper IgM syndrome. A comparative study of the peripheral blood B cell subsets between patients and healthy donors showed that in patients with autoimmune manifestations all circulating B cells expressed high amounts of surface IgM. CONCLUSIONS: These results suggest that the increased IgM expression on circulating B cells, reflecting B cell activation, might identify a clinical condition characterized by hyper IgM serum levels of unknown molecular defects, associated with susceptibility to infections and autoimmunity.

Serum Bile Acid Levels in Children With Nonalcoholic Fatty Liver Disease.

OBJECTIVE: Because the prevalence of obesity in children is increasing, the frequency of pediatric nonalcoholic fatty liver disease (NAFLD) is growing. A reliable noninvasive biomarker for monitoring progression of liver fibrosis would be useful. In cirrhotic persons serum bile acid (BA) levels are significantly elevated. We hypothesized that BA levels and composition in pediatric NAFLD vary depending on the stage of fibrosis. METHODS: Children with NAFLD were compared with controls and classified by stages of fibrosis (NAFLD-F0, n = 27; NAFLD-F≥1, n = 65) based on liver-biopsy findings. Fasted metabolic and cholestasis status was assessed by several blood tests. BA profiles were measured by tandem mass spectrometry and compared with healthy controls (n = 105). RESULTS: Compared with controls, all of the NAFLD patients were overweight and showed significantly elevated glucose, insulin, aspartate transaminase, and alanine transaminase levels. Total serum BAs were lower in nonfibrotic NAFLD children than in a control cohort (1.73 vs 3.6 µmol/L) because low glycine-conjugated BA levels were incompletely compensated by increases in taurine-conjugated or unconjugated BA. In patients with fibrotic NAFLD, BA levels were lower than in controls (2.45 vs 3.6 µmol/L) but higher than in nonfibrotic patients (2.45 vs 1.73 µmol/L), and the BA pattern resembled that of healthy controls. Fibroblast growth factor 19 levels were significantly lower in both NAFLD groups than in controls (P ≤ 0.001) and were positively correlated with ursodeoxycholic acid levels. CONCLUSIONS: Our data indicate that serum BA levels decrease in early NAFLD and increase during progression to fibrosis. Given that BA levels are increased in cirrhotic adults, we postulate a continuous rise as NAFLD advances. BA may have a value as a noninvasive biomarker in pediatric NAFLD progression.

Toll-like receptor-mediated signaling cascade as a regulator of the inflammation network during alcoholic liver disease.

Chronic abuse of alcohol leads to various histological abnormalities in the liver. These are conditions collectively known as alcoholic liver disease (ALD). Currently, ALD is considered to be one of the major causes of death worldwide. An impaired intestinal barrier with related endotoxemia is among the various pathogenetic factors. This is mainly characterized by circulating levels of lipopolysaccharide (LPS), considered critical for the onset of intra-hepatic inflammation. This in turn promotes hepatocellular damage and fibrosis in ALD. Elevated levels of LPS exert their effects by binding to Toll-like receptors (TLRs) which are expressed by all liver-resident cells. The activation of TLR signaling triggers an overproduction and release of some cytokines, which promote an autocatalytic cascade of other pro-inflammatory signals. In this review, we provide an overview of the mechanisms that sustain LPS-mediated activation of TLR signaling, reporting current experimental and clinical evidence of its role during inflammation in ALD.

Plasma levels of homocysteine and cysteine increased in pediatric NAFLD and strongly correlated with severity of liver damage.

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of metabolic abnormalities ranging from simple triglyceride accumulation in the hepatocytes to hepatic steatosis with inflammation, ballooning and fibrosis. It has been demonstrated that the pathogenesis of NAFLD involves increased oxidative stress, with consumption of the major cellular antioxidant, glutathione (GSH). Liver has a fundamental role in sulfur compound metabolism, although the data reported on plasma thiols status in NAFLD are conflicting. We recruited 63 NAFLD patients, and we analyzed all plasma thiols, such as homocysteine (Hcy), cysteine (Cys), cysteinylglycine (CysGly) and GSH, by high-performance liquid chromatography (HPLC) with fluorescence detection. Hcy, Cys and CysGly plasma levels increased in NAFLD patients (p < 0.0001); whereas GSH levels were decreased in NAFLD patients when compared to controls (p < 0.0001). On the contrary, patients with steatohepatitis exhibited lower levels of Hcy and Cys than subjects without. Furthermore, a positive correlation was found between Hcy and Cys and the presence of fibrosis in children with NAFLD. Taken together, these data demonstrated a defective hepatic sulfur metabolism in children with NAFLD, and that high levels of Hcy and Cys probably correlates with a pattern of more severe histological liver damage, due to mechanisms that require further studies.

MicroRNAs as controlled systems and controllers in non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a multi-faceted condition including simple steatosis alone or associated with inflammation and ballooning (non-alcoholic steatohepatitis) and eventually fibrosis. The NAFLD incidence has increased over the last twenty years becoming the most frequent chronic liver disease in industrialized countries. Obesity, visceral adiposity, insulin resistance, and many other disorders that characterize metabolic syndrome are the major predisposing risk factors for NAFLD. Furthermore, different factors, including genetic background, epigenetic mechanisms and environmental factors, such as diet and physical exercise, contribute to NAFLD development and progression. Several lines of evidence demonstrate that specific microRNAs expression profiles are strongly associated with several pathological conditions including NAFLD. In NAFLD, microRNA deregulation in response to intrinsic genetic or epigenetic factors or environmental factors contributes to metabolic dysfunction. In this review we focused on microRNAs role both as controlled and controllers molecules in NAFLD development and/or their eventual value as non-invasive biomarkers of disease.

Preliminary results on clinical effects of probiotic Lactobacillus salivarius LS01 in children affected by atopic dermatitis.

GOALS: The goal of this study was to evaluate the clinical efficacy of an intake of Lactobacillus salivarius LS01 (DSM 22775) for the treatment of atopic dermatitis (AD) in children. BACKGROUND: AD is an inflammatory and pruritic chronic relapsing skin disorder with multifactorial etiopathology. Some evidence suggests that probiotics may improve AD by modulating the immune system and the composition of intestinal microbiota. STUDY: A total of 43 patients aged from 0 to 11 years were enrolled in the study (M/F ratio=1:1) and treated with the probiotic strain L. salivarius LS01. Clinical efficacy of probiotic treatment was assessed from baseline by changes in itch index and in the objective SCORAD/SCORAD index. RESULTS: Patients being given probiotic treatment showed a significant improvement in clinical parameters (SCORAD and itch values) from baseline. The reduction in SCORAD and itch index observed after 4 weeks of treatment also persisted after the cessation of probiotic supplementation. CONCLUSIONS: L. salivarius LS01 seems to be able to improve the quality of life of children affected by AD and, as a consequence, it may have promising clinical and research implications.

Plasma high mobility group box 1 protein reflects fibrosis in pediatric nonalcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) affects 3-12% of the general pediatric population. HMGB1 protein is presently considered a potent inflammatory mediator in several liver diseases, even if its role in NAFLD is still unknown in clinical studies. Here we investigated the relationships between circulating HMGB1, TGF-ß and MCP-1 and liver damage in pediatric NAFLD. HMGB1, TGF-ß and MCP-1 plasma levels were measured in 110 obese children with biopsy-proven NAFLD and 40 age-matched obese controls. HMGB1, TGF-ß and MCP-1, ALT, AST and cholesterol plasma levels were significantly higher in NAFLD than in control children. A significant association between increased levels of HMGB1, TGF-ß and MCP-1 and high degrees of fibrosis was found. In this study, we showed for the first time that circulating levels of HMGB1 were raised in children with NAFLD and strongly correlated with fibrosis and systemic inflammation.

EZH2 down-regulation exacerbates lipid accumulation and inflammation in in vitro and in vivo NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent, chronic liver diseases, worldwide. It is a multifactorial disease caused by complex interactions between genetic, epigenetic and environmental factors. Recently, several microRNAs, some of which epigenetically regulated, have been found to be up- and/or down-regulated during NAFLD development. However, in NAFLD, the essential role of the Polycomb Group protein Enhancer of Zeste Homolog 2 (EZH2), which controls the epigenetic silencing of specific genes and/or microRNAs by trimethylating Lys27 on histone H3, still remains unknown. In this study, we demonstrate that the nuclear expression/activity of the EZH2 protein is down-regulated both in livers from NAFLD rats and in the free fatty acid-treated HepG2. The drop in EZH2 is inversely correlated with: (i) lipid accumulation; (ii) the expression of pro-inflammatory markers including TNF-α and TGF-ß; and (iii) the expression of miR-200b and miR-155. Consistently, the pharmacological inhibition of EZH2 by 3-Deazaneplanocin A (DZNep) significantly reduces EZH2 expression/activity, while it increases lipid accumulation, inflammatory molecules and microRNAs. In conclusion, the results of this study suggest that the defective activity of EZH2 can enhance the NAFLD development by favouring steatosis and the de-repression of the inflammatory genes and that of specific microRNAs.

Association between Serum Atypical Fibroblast Growth Factors 21 and 19 and Pediatric Nonalcoholic Fatty Liver Disease.

Atypical fibroblast growth factors (FGF) 21 and 19 play a central role in energy metabolism through the mediation of Klotho coreceptor. Contradictory findings are available about the association of FGF21 and FGF19 with nonalcoholic fatty liver disease (NAFLD) in humans. We investigated the association of serum FGF21, FGF19 and liver Klotho coreceptor with non-alcoholic steatohepatitis (NASH) and fibrosis in children with NAFLD. Serum FGF21 and FGF19 were measured in 84 children with biopsy-proven NAFLD and 23 controls (CTRL). The hepatic expression of Klotho coreceptor was measured in 7 CTRL, 9 patients with NASH (NASH+) and 11 patients without NASH (NASH-). FGF21 and FGF19 showed a tendency to decrease from CTRL (median FGF21 = 196 pg/mL; median FGF19 = 201 pg/mL) to NASH- (FGF21 = 89 pg/mL; FGF19 = 81 pg/mL) to NASH+ patients (FGF21 = 54 pg/mL; FGF19 = 41 pg/mL) (p<0.001 for all comparisons) and were inversely associated with the probability of NASH and fibrosis in children with NAFLD. The hepatic expression of Klotho coreceptor was inversely associated with NASH (R(2) = 0.87, p<0.0001) and directly associated with serum FGF21 (R(2) = 0.57, p<0.0001) and FGF19 (R(2) = 0.67, p<0.0001). In conclusion, serum FGF19 and FGF21 and hepatic Klotho expression are inversely associated with hepatic damage in children with NAFLD and these findings may have important implications for understanding the mechanisms of NAFLD progression.

Dual role of microRNAs in NAFLD.

MicroRNAs are important post-transcriptional regulators in different pathophysiological processes. They typically affect the mRNA stability or translation finally leading to the repression of target gene expression. Notably, it is thought that microRNAs are crucial for regulating gene expression during metabolic-related disorders, such as nonalcoholic fatty liver disease (NAFLD). Several studies identify specific microRNA expression profiles associated to different histological features of NAFLD, both in animal models and in patients. Therefore, specific assortments of certain microRNAs could have enormous diagnostic potentiality. In addition, microRNAs have also emerged as possible therapeutic targets for the treatment of NAFLD-related liver damage. In this review, we discuss the experimental evidence about microRNAs both as potential non-invasive early diagnostic markers and as novel therapeutic targets in NAFLD and its more severe liver complications.

Gut-liver axis and fibrosis in nonalcoholic fatty liver disease: an input for novel therapies.

Non-alcoholic fatty liver disease is a multifactorial condition, ranging from simple steatosis to non-alcoholic steatohepatitis with or without fibrosis. In non-alcoholic fatty liver disease, alteration of gut microbiota and increased intestinal permeability increase exposure of the liver to gut-derived bacterial products: lipopolysaccharides and unmethylated CpG DNA. These products stimulate innate immune receptors, namely Toll-like receptors, which activate signalling pathways involved in liver inflammation and fibrogenesis. Currently, there are several studies on the involvement of lipopolysaccharide-activated Toll-like receptor 4 signalling in non-alcoholic fatty liver disease pathogenesis. There has been widespread interest in the study of the involvement of resident hepatic stellate cells and Kupffer cells activation in liver fibrogenesis upon TLR4 stimulation. Although the best evidence to support a role for gut microbiota in non-alcoholic fatty liver disease-induced fibrosis comes largely from animal models, data from human studies are accumulating and could lead to new therapeutic approaches. Therapeutic modulation of gut microflora may be an alternative strategy to develop an anti-fibrotic therapy. In this review, we discuss the relevant role of gut-liver axis in non-alcoholic liver disease-associated liver fibrosis and discuss the evidence on novel anti-fibrotic therapeutic approaches.