GFAP serves as a structural element of tunneling nanotubes between glioblastoma cells and could play a role in the intercellular transfer of mitochondria

Tunneling nanotubes (TNTs) are long F-actin-positive plasma membrane bridges connecting distant cells, allowing the intercellular transfer of cellular cargoes, and are found to be involved in glioblastoma (GBM) intercellular crosstalk. Glial fibrillary acid protein (GFAP) is a key intermediate filament protein of glial cells involved in cytoskeleton remodeling and linked to GBM progression. Whether GFAP plays a role in TNT structure and function in GBM is unknown. Here, analyzing F-actin and GFAP localization by laser-scan confocal microscopy followed by 3D reconstruction (3D-LSCM) and mitochondria dynamic by live-cell time-lapse fluorescence microscopy, we show the presence of GFAP in TNTs containing functional mitochondria connecting distant human GBM cells. Taking advantage of super-resolution 3D-LSCM, we show the presence of GFAP-positive TNT-like structures in resected human GBM as well. Using H2O2 or the pro-apoptotic toxin staurosporine (STS), we show that GFAP-positive TNTs strongly increase during oxidative stress and apoptosis in the GBM cell line. Culturing GBM cells with STS-treated GBM cells, we show that STS triggers the formation of GFAP-positive TNTs between them. Finally, we provide evidence that mitochondria co-localize with GFAP at the tip of close-ended GFAP-positive TNTs and inside receiving STS-GBM cells. Summarizing, here we found that GFAP is a structural component of TNTs generated by GBM cells, that GFAP-positive TNTs are upregulated in response to oxidative stress and pro-apoptotic stress, and that GFAP interacts with mitochondria during the intercellular transfer. These findings contribute to elucidate the molecular structure of TNTs generated by GBM cells, highlighting the structural role of GFAP in TNTs and suggesting a functional role of this intermediate filament component in the intercellular mitochondria transfer between GBM cells in response to pro-apoptotic stimuli.

Efficacy and safety of capsule endoscopy in octogenarian patients: a retrospective study

BACKGROUND

Life expectancy and the number of ultra-octogenarians increased significantly, thus making crucial the appropriateness of several endoscopic procedures in elderly patients. The aim of our study was to provide a retrospective analysis of the efficacy and safety of capsule endoscopy (CE) in patients aged over 80 years.

METHODS

In this single-centre study, 900 patients underwent capsule endoscopy between 2002 and 2015 for different indications; of these 106 patients aged ≥80 years (group A) and 99 patients aged 40-60 years (control group B) were retrospectively selected.

RESULTS

Occult gastrointestinal bleeding accounted for 62.1% of all indications for capsule endoscopy in group B, compared to 95.2% in group A (P<0.001). Although not statistically significant, the diagnostic yield was higher in group A (71%) vs. group B (62%). The percentages of reaching the cecum and the median gastric transit time were uniform within the two groups. In contrast, small bowel transit time was longer in group A vs. B. Small bowel preparation was similar in the two groups. The exam was generally well tolerated in both groups, with capsule aspiration being one of the main adverse events, which occurred in two elderly patients.

CONCLUSIONS

Our data expand previous findings confirming that capsule endoscopy can be performed safely even in very old patients and show that the diagnostic yield is similar to that of younger patients.

Intercellular crosstalk mediated by tunneling nanotubes between central nervous system cells. What we need to advance

Long-range intercellular communication between Central Nervous System (CNS) cells is an essential process for preserving CNS homeostasis. Paracrine signaling, extracellular vesicles, neurotransmitters and synapses are well-known mechanisms involved. A new form of intercellular crosstalk mechanism based on Tunneling Nanotubes (TNTs), suggests a new way to understand how neural cells interact with each other in controlling CNS functions. TNTs are long intercellular bridges that allow the intercellular transfer of cargoes and signals from one cell to another contributing to the control of tissue functionality. CNS cells communicate with each other via TNTs, through which ions, organelles and other signals are exchanged. Unfortunately, almost all these results were obtained through 2D in-vitro models, and fundamental mechanisms underlying TNTs-formation still remain elusive. Consequently, many questions remain open, and TNTs role in CNS remains largely unknown. In this review, we briefly discuss the state of the art regarding TNTs identification and function. We highlight the gaps in the knowledge of TNTs and discuss what is needed to accelerate TNTs-research in CNS-physiology. To this end, it is necessary to: 1) Develop an ad-hoc TNTs-imaging and software-assisted processing tool to improve TNTs-identification and quantification, 2) Identify specific molecular pathways involved into TNTs-formation, 3) Use in-vitro 3D-CNS and animal models to investigate TNTs-role in a more physiological context pushing the limit of live-microscopy techniques. Although there are still many steps to be taken, we believe that the study of TNTs is a new and fascinating frontier that could significantly contribute to deciphering CNS physiology.

Predictors of serious adverse events and non-response in cirrhotic patients with primary biliary cholangitis treated with obeticholic acid

BACKGROUND & AIMS

Obeticholic acid (OCA) has recently been restricted in patients with primary biliary cholangitis (PBC) with "advanced cirrhosis" because of its narrow therapeutic index. We aimed to better define the predicting factors of hepatic serious adverse events (SAEs) and non-response in cirrhotic patients undergoing OCA therapy.

METHODS

Safety and efficacy of treatment were evaluated in a cohort of consecutive PBC cirrhotic patients started with OCA. OCA response was evaluated according to the Poise criteria. Risk factors for hepatic SAEs and non-response were reported as risk ratios (RR) with 95% confidence intervals (CIs).

RESULTS

One hundred PBC cirrhotics were included, 97 Child-Pugh class A and 3 class B. Thirty-one had oesophageal varices and 5 had a history of ascites. Thirty-three per cent and 32% of patients achieved a biochemical response at 6 and 12 months respectively. Male sex (adjusted-RR 1.75, 95%CI 1.42-2.12), INR (1.37, 1.00-1.87), Child-Pugh score (1.79, 1.28-2.50), MELD (1.17, 1.04-1.30) and bilirubin (1.83, 1.11-3.01) were independently associated with non-response to OCA. Twenty-two patients discontinued OCA within 12 months: 10 for pruritus, 9 for hepatic SAEs (5 for jaundice and/or ascitic decompensation; 4 for upper digestive bleeding). INR (adjusted-RR 1.91, 95%CI 1.10-3.36), lower albumin levels (0.18, 0.06-0.51), Child-Pugh score (2.43, 1.50-4.04), history of ascites (3.5, 1.85-6.5) and bilirubin (1.30, 1.05-1.56), were associated with hepatic SAEs. A total bilirubin≥1.4 mg/dl at baseline was the most accurate biochemical predictor of hepatic SAEs under OCA.

CONCLUSIONS

An accurate baseline assessment is crucial to select cirrhotic patients who can benefit from OCA. Although OCA is effective in one third of cirrhotics, bilirubin level ≥1.4 mg/dl should discourage from its use.

On-treatment serum albumin level can guide long-term treatment in patients with cirrhosis and uncomplicated ascites

BACKGROUND & AIMS

The ANSWER study reported that long-term albumin administration in patients with cirrhosis and uncomplicated ascites improves survival. During treatment, serum albumin increased within a month and remained stable thereafter. In this post hoc analysis, we aimed to determine whether on-treatment serum albumin levels could guide therapy.

METHODS

Logistic regression was used to assess the association between baseline serum albumin and mortality, as well as to determine on-treatment factors associated with mortality and to predict the achievement of a given on-treatment serum albumin level. Survival was assessed by Kaplan-Meier estimates and second-order polynomial regression. Patients whose on-treatment serum albumin remained below normal were compared with a subset of patients from the control arm matched by principal score.

RESULTS

Baseline serum albumin was closely associated with 18-month mortality in untreated patients; albumin treatment almost effaced this relationship. On-treatment serum albumin and MELD-Na at month 1 were the sole independent variables associated with mortality. Second-order polynomial regression revealed that survival improved in parallel with increased 1-month on-treatment serum albumin. Kaplan-Meier estimations showed that any value of 1-month on-treatment serum albumin (0.1 g/dl intervals) in the range 2.5-4.5 g/dl discriminated patient survival. In the normal range of serum albumin, the best discriminant value was 4.0 g/dl. Compared to untreated patients, survival even improved in patients whose on-treatment serum albumin remained below normal.

CONCLUSION

Baseline serum albumin per se should not guide the decision to start albumin therapy. Conversely, 1-month on-treatment serum albumin levels are strongly associated with outcomes and could guide the use of albumin - 4.0 g/dl being the target threshold. However, even patients whose serum albumin remains below normal benefit from long-term albumin administration.

LAY SUMMARY

The ANSWER study has shown that long-term albumin administration improves survival and prevents the occurrence of major complications in patients with cirrhosis and ascites. This study shows that the achievement of these beneficial effects is related to a significant increase in serum albumin concentration. Even though the best results follow the achievement of a serum albumin concentration of 4 g/dl, a survival benefit is also achieved in patients who fail to normalise serum albumin.

Entheseal involvement in asymptomatic human immunodeficiency virus infected patients: preliminary results of a clinical and ultrasonographic study

OBJECTIVES

As a strong association between human immunodeficiency virus (HIV) infection and spondyloarthritis (SpA) has been hypothesised, our main objective was to explore by power Doppler ultrasonography (PDUS) the presence of subclinical enthesitis in asymptomatic HIV patients. The presence of subclinical synovitis was also evaluated.

METHODS

Consecutive asymptomatic HIV patients were studied and compared with asymptomatic HCV patients and healthy controls (HC). All subjects underwent a clinical and PDUS bilateral examination of the following entheses and joints: epicondyle, quadriceps, patellar, Achilles and plantar fascia; wrists, II and III metacarpo-phalangeal, knee and ankle.

RESULTS

Twenty-nine HIV, 32 HCV and 25 HC were recruited; 1.032 entheses and 860 joints were examined. Clinical diagnosis of enthesitis was made in 10.3% HIV patients, 6.2% HCV patients (p=0.66) and none HC (p=0.24). PDUS enthesitis was found in 72.4% HIV, 28.1% HCV (p=0.0008) and 12% HC (p<0.0001). Clinical diagnosis of synovitis was made in 3.4% HIV patients, 9.3% HCV patients (p=0.61) and none HC (p=1). PDUS abnormalities were documented in 24.1% HIV patients, 71.8% HCV patients (p=0.0003) and none HC (p=0.0001). In detecting enthesitis and synovitis, PDUS was more sensitive than clinical examination both in HIV and HCV patients.

CONCLUSIONS

Our preliminary study shows the high frequency of PDUS enthesitis in asymptomatic HIV patients, which highlights the close link between HIV and SpA. Further studies are desirable on a larger number of HIV patients to confirm these results. PDUS proved to be more sensitive than clinical examination in detecting subclinical involvement of entheses and joints.

Long-term albumin administration in decompensated cirrhosis (ANSWER): an open-label randomised trial

BACKGROUND

Evidence is scarce on the efficacy of long-term human albumin (HA) administration in patients with decompensated cirrhosis. The human Albumin for the treatmeNt of aScites in patients With hEpatic ciRrhosis (ANSWER) study was designed to clarify this issue.

METHODS

We did an investigator-initiated multicentre randomised, parallel, open-label, pragmatic trial in 33 academic and non-academic Italian hospitals. We randomly assigned patients with cirrhosis and uncomplicated ascites who were treated with anti-aldosteronic drugs (≥200 mg/day) and furosemide (≥25 mg/day) to receive either standard medical treatment (SMT) or SMT plus HA (40 g twice weekly for 2 weeks, and then 40 g weekly) for up to 18 months. The primary endpoint was 18-month mortality, evaluated as difference of events and analysis of survival time in patients included in the modified intention-to-treat and per-protocol populations. This study is registered with EudraCT, number 2008-000625-19, and ClinicalTrials.gov, number NCT01288794.

FINDINGS

From April 2, 2011, to May 27, 2015, 440 patients were randomly assigned and 431 were included in the modified intention-to-treat analysis. 38 of 218 patients died in the SMT plus HA group and 46 of 213 in the SMT group. Overall 18-month survival was significantly higher in the SMT plus HA than in the SMT group (Kaplan-Meier estimates 77% vs 66%; p=0·028), resulting in a 38% reduction in the mortality hazard ratio (0·62 [95% CI 0·40-0·95]). 46 (22%) patients in the SMT group and 49 (22%) in the SMT plus HA group had grade 3-4 non-liver related adverse events.

INTERPRETATION

In this trial, long-term HA administration prolongs overall survival and might act as a disease modifying treatment in patients with decompensated cirrhosis.

FUNDING

Italian Medicine Agency.

Mortality risk according to different clinical characteristics of first episode of liver decompensation in cirrhotic patients: a nationwide, prospective, 3-year follow-up study in Italy

OBJECTIVES

The occurrence of decompensation marks a crucial turning point in the course of cirrhosis. The purpose of this study was to assess the risk of mortality according to the clinical characteristics of first decompensation, considering also the impact of acute-on-chronic liver failure (AoCLF).

METHODS

We conducted a prospective nationwide inception cohort study in Italy. Decompensation was defined by the presence of ascites, either overt or detected by ultrasonography (UD), gastroesophageal variceal bleeding (GEVB), and hepatic encephalopathy (HE). AoCLF was defined according to the Asian Pacific Association for the Study of the Liver criteria. Multivariable Cox proportional hazards regression was used to analyze the risk of failure (death or orthotopic liver transplantation (OLT)).

RESULTS

A total of 490 consecutive cirrhotic patients (314 males, mean age 60.9±12.6 years) fulfilled the study criteria. AoCLF was identified in 59 patients (12.0%). Among the remaining 431 patients, ascites were found in 330 patients (76.6%): in 257 (77.8%) as overt ascites and in 73 (22.2%) as UD ascites. GEVB was observed in 77 patients (17.9%) and HE in 30 patients (7.0%). After a median follow-up of 33 months, 24 patients underwent OLT and 125 died. The cumulative incidence of failure (death or OLT) after 1, 2, and 3 years was, respectively, 28, 53, and 62% in patients with AoCLF; 10, 18, and 25% in patients with UD ascites; 17, 31, and 41% in patients with overt ascites; and 8, 12, and 24% in patients with GEVB (P<0.0001).

CONCLUSIONS

AoCLF is responsible for a relevant proportion of first decompensation in cirrhotic patients and is associated with the poorest outcome. Patients with UD ascites do not have a negligible mortality rate and require clinical monitoring similar to that of patients with overt ascites.

Individual and social learning processes involved in the acquisition and generalization of tool use in macaques

Macaques can efficiently use several tools, but their capacity to discriminate the relevant physical features of a tool and the social factors contributing to their acquisition are still poorly explored. In a series of studies, we investigated macaques' ability to generalize the use of a stick as a tool to new objects having different physical features (study 1), or to new contexts, requiring them to adapt the previously learned motor strategy (study 2). We then assessed whether the observation of a skilled model might facilitate tool-use learning by naive observer monkeys (study 3). Results of study 1 and study 2 showed that monkeys trained to use a tool generalize this ability to tools of different shape and length, and learn to adapt their motor strategy to a new task. Study 3 demonstrated that observing a skilled model increases the observers' manipulations of a stick, thus facilitating the individual discovery of the relevant properties of this object as a tool. These findings support the view that in macaques, the motor system can be modified through tool use and that it has a limited capacity to adjust the learnt motor skills to a new context. Social factors, although important to facilitate the interaction with tools, are not crucial for tool-use learning.

Portal hypertensive enteropathy diagnosed by capsule endoscopy and demonstration of the ileal changes after transjugular intrahepatic portosystemic shunt placement: a case report

Introduction

Recent data suggest that mucosal abnormalities can occur even in the duodenum, jejunum, and distal ileum of cirrhosis patients. We present a case of portal hypertensive enteropathy in a cirrhosis patient shown by capsule endoscopy and the effect of transjugular intrahepatic portosystemic shunt on the ileal pictures.

Case presentation

An 83-year-old Caucasian woman was admitted to our hospital for anemia and a positive fecal occult blood test. An upper gastrointestinal endoscopy revealed small varices without bleeding signs and hypertensive gastropathy. Colonoscopy was negative. To rule out any other cause of bleeding, capsule endoscopy was performed; capsule endoscopy revealed severe hyperemia of the jejunum-ileal mucosa with active bleeding. Because of the persistence of anemia and the frequent blood transfusions, not responding to β-blocker drugs or octreotide infusion, a transjugular intrahepatic portosystemic shunt was performed. Anemia improved quickly after the transjugular intrahepatic portosystemic shunt, and no further blood transfusion was necessary in the follow-up. The patient developed portal encephalopathy two months later and was readmitted to our department. We repeated the capsule endoscopy that showed a significant improvement of the gastric and ileal mucosa without any signs of bleeding.

Conclusion

Hypertensive enteropathy is a rare condition, but it seems more common with the introduction of capsule endoscopy in clinical practice. This case shows that the jejunum can be a source of bleeding in cirrhosis patients, and this is the first demonstration of its resolution after transjugular intrahepatic portosystemic shunt placement.

Selective COX-1 inhibition: A therapeutic target to be reconsidered

Since cyclooxygenase (COX) isozymes discovery, many papers and reviews have been published to describe the structural bases of COX inhibition, and to debate on the therapeutic and adverse effects of worldwide clinically used nonsteroidal anti-inflammatory drugs (NSAIDs), included COX-2 selective inhibitors (well known as Coxibs). COX-2 inhibition has been widely investigated, whereas the role of COX-1 in human pathophysiology is mostly not yet well ascertained. As time goes on, the cliché that the constitutively expressed isoform COX-1 is only involved in normal physiological functions, such as platelet aggregation, gastric mucosa protection and renal electrolyte homeostasis is going to be shattered. Low-dose aspirin, behaving as a preferential inhibitor of platelet COX-1, allowed to enlighten the role exerted by this isoenzyme in many mammalian cell types. This review would elucidate the most recent findings on selective COX-1 inhibition and their relevance to human pathology such as cancer, neuro-inflammation, cardioprotection, fever and pain. It would also focus on the design and development of new highly selective COX-1 inhibitors, useful tools in pharmacological studies aimed at gaining a deeper insight of the role of COX-1 in human health and disease. Among the traditional NSAIDs, other then aspirin and indomethacin, only few examples of selective COX-1 inhibitors (SC-560, FR122047, mofezolac, P6 and TFAP) have been so far identified. This review has also the scope to stimulate the development of novel drugs, which activity is COX-1 mediated.

Occult intestinal haemorrhage due to lipoma of the small bowel detected with the combined use of the new endoscopic techniques. A report of two cases

We report two unusual cases of occult intestinal bleeding due to lipoma of the small bowel. Both the patients underwent several inconclusive endoscopic and radiological procedures before the diagnosis of these lesions that was possible using video capsule endoscopy and double balloon enteroscopy. In the first case, the finding of capsule endoscopy was confirmed using enteroscopy, allowing us to diagnose the ileal mass. In the second and more recent case, we used double balloon enteroscopy for the further characterisation and management of the ileal lipoma. Lipoma is a very rare cause of intestinal bleeding and we describe the management and the outcome of our patients.

Different production of soluble HLA-G antigens by peripheral blood mononuclear cells in ulcerative colitis and Crohn's disease: a noninvasive diagnostic tool?

BACKGROUND

HLA-G antigens are nonclassical major histocompatibility complex (MHC) class I molecules characterized by tolerogenic and antiinflammatory properties. Recently, a different expression of HLA-G antigens has been observed between intestinal biopsies of ulcerative colitis (UC) and Crohn's disease (CD) patients. These data suggested a functional role for HLA-G molecules in the diseases and proposed the HLA-G modulation as a marker for the diagnosis of UC and CD. The soluble HLA-G antigens (sHLA-G) are circulating molecules mainly produced by activated peripheral blood CD14+ monocytes.

METHODS

We tested, by specific enzyme-linked immunosorbent assay (ELISA), the sHLA-G molecule levels in the supernatants of unstimulated and bacterial lipopolysaccharide (LPS)-stimulated cultures of peripheral blood mononuclear cells (PBMC) from 30 healthy subjects, 10 CD, and 18 UC patients. The data were not influenced by treatment or disease activity.

RESULTS

The results confirmed a different sHLA-G expression between the diseases, with a spontaneous secretion of sHLA-G in CD patients but not in UC and healthy subjects. Moreover, a lack of sHLA-G antigens has been reported in UC patient cultures after LPS activation but not in healthy subjects and CD patients. The defective sHLA-G production was related to an impaired IL-10 secretion in UC but not in CD.

CONCLUSIONS

Overall, these results confirm the presence of a different biological characteristic between CD and UC patients and suggest sHLA-G production by PBMC as a noninvasive diagnostic tool in the early phases of the diseases.

[Stool antigen test for diagnosis of Helicobacter pylori infection. Merely a research opportunity, or an effective diagnostic tool?]

Since Helicobacter pylori (H. pylori) infection was recognized as a major cause of peptic ulcer disease and an important risk factor for gastric malignancy, several strategies have been used to diagnose it. These methods are split up along two lines: 1) direct detection of the bacteria, and 2) detection of antigen-antibody assay against H. pylori, or anyhow detection of H. pylori by indirect methods. In this review of literature about the methods to diagnose H. pylori infection, we focused in particular on the non-invasive tests based on H. pylori antigens detection in faeces. Some meta-analyses showed that immunoenzymatic stool tests can be considered reliable in untreated patients, whereas further confirmations are needed before extending their use also in anti-H. pylori treated patients. As it concerns cost-analysis, immunoenzymatic stool test is the most cost-effective among the tests today available. Finally, a newly developed office-based stool test has been evaluated. It does not require laboratory assay, and the results are available within 10 minutes. Preliminary data about its clinical usefulness are promising, but further and wider confirmations are needed, as it has been put on the market quite recently.

[Surveillance and cost-effectiveness of colonoscopy in asymptomatic increased risk subjects of colorectal cancer: Ferrara experience]

Colorectal cancer represents the second leading cause of cancer deaths in western countries with elevated costs for health service. It's very important to develop screening and surveillance programs for cancer prevention with "cost-effective" means. We present a surveillance program with colonoscopy focused on first degree relatives of CRC patients. Colonoscopy is a "cost-effective" mean of screening for high risk subjects.

Construction and in vitro functional evaluation of a low-density lipoprotein receptor/transferrin fusion protein as a therapeutic tool for familial hypercholesterolemia

A cDNA sequence encoding a soluble form of the human low-density lipoprotein receptor (LDL-R) was produced by RT-PCR amplification. This form of the receptor contains the N-terminal cysteine-rich domain, the EGF homology domain, and the serine/threonine-rich domain, but lacks the membrane anchor as well as the cytoplasmic domain. By the same technical approach a cDNA sequence encoding rabbit transferrin was generated. In-frame fusion of the two cDNAs produced a sequence encoding a chimeric protein potentially capable of binding LDL on the N-terminal side and the transferrin receptor on the C-terminal side. It was expected that LDL bound to the chimeric protein could be internalized, targeted to an acidic compartment, and processed through the pathway of the transferrin receptor. Cells transfected with the LDL-R/transferrin cDNA translate, glycosylate, and secrete the corresponding protein in the culture medium. The secreted protein binds LDL in a ligand-blotting experiment. Finally, the chimeric protein mediates the binding and internalization of LDL in mutant cells lacking the LDL receptor. In fact, Watanabe rabbit fibroblasts, incubated with the chimeric protein show a fourfold increase in LDL binding, a fivefold increase in LDL internalization, and a sixfold increase in LDL degradation, with respect to unincubated fibroblasts.