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ABSTRACTThe propensity to accumulate high-value metabolites under specific conditions makes microalgae promising candidates for commercial applications. Here, the freshwater microalga Cyanophora paradoxaCCAP 981/1 was cultivated under varying conditions (control, nitrogen limitation, NaCl supplementation and blue light exposure) and the biological activity of the corresponding biomass extracts was assessed against human breast (MCF-7) and lung (A549) cancer cell lines. The stress treatments hindered the growth of C. paradoxa, the control displaying the highest specific growth rate (0.16 d−1± 0.01). Biomass screening by GCMS and HPLC identified diverse bioactive compounds including pigments (chlorophylls, xanthophylls, carotenes) and fatty acids (e.g., EPA). The control cultivation conditions returned the highest yields of biomass (724 mg), zeaxanthin (6.8 mg g−1), EPA (1.1 mg g−1) and phycocyanin (113.9 mg g−1), while the blue light treatment enhanced the proportions of unsaturated forms of C18 (34.3%). Extracts of dried biomass obtained by cold maceration using solvents of increasing polarity were used in the treatment of MCF-7 and A549 cancer cells. Ethyl acetate extracts from nitrogen-limited cultures reduced MCF-7 viability (~70%) after 72 h. However, the diethyl ether and methanol extracts showed no impact on MCF-7 and A549 cell viability. Furthermore, acridine orange staining revealed no significant DNA damage in these cell lines upon exposure to C. paradoxaextracts. Overall, the minimal impacts on cell viability observed here supports considering C. paradoxaas a promising source of natural bioactive compounds with applications in various biotechnological sectors.

Safe, efficient and specific nano-delivery systems are essential for current and emerging therapeutics, precision medicine and other biotechnology sectors. Novel bio-based nanotechnologies have recently arisen, which are based on the exploitation of extracellular vesicles (EVs). In this context, it has become essential to identify suitable organisms or cellular types to act as reliable sources of EVs and to develop their pilot- to large-scale production. The discovery of new biosources and the optimisation of related bioprocesses for the isolation and functionalisation of nano-delivery vehicles are fundamental to further develop therapeutic and biotechnological applications. Microalgae constitute sustainable sources of bioactive compounds with a range of sectorial applications including for example the formulation of health supplements, cosmetic products or food ingredients. In this study, we demonstrate that microalgae are promising producers of EVs. By analysing the nanosized extracellular nano-objects produced by eighteen microalgal species, we identified seven promising EV-producing strains belonging to distinct lineages, suggesting that the production of EVs in microalgae is an evolutionary conserved trait. Here we report the selection process and focus on one of this seven species, the glaucophyte Cyanophora paradoxa, which returned a protein yield in the small EV fraction of 1 μg of EV proteins per mg of dry weight of microalgal biomass (corresponding to 109particles per mg of dried biomass) and EVs with a diameter of 130 nm (mode), as determined by the micro bicinchoninic acid assay, nanoparticle tracking and dynamic light scattering analyses. Moreover, the extracellular nanostructures isolated from the conditioned media of microalgae species returned positive immunoblot signals for some commonly used EV-biomarkers such as Alix, Enolase, HSP70, and β-actin. Overall, this work establishes a platform for the efficient production of EVs from a sustainable bioresource and highlights the potential of microalgal EVs as novel biogenic nanovehicles.

Extracellular vesicles (EVs) are membrane-enclosed biological nanoparticles with potential as diagnostic markers and carriers for therapeutics. Characterization of EVs poses severe challenges due to their complex structure and composition, requiring the combination of orthogonal analytical techniques. Here, we demonstrate how liquid chromatography combined with multi-angle light scattering (MALS) and fluorescence detection in one single apparatus can provide multiparametric characterization of EV samples, including concentration of particles, average diameter of the particles, protein amount to particle number ratio, presence of EV surface markers and lipids, EV shape, and sample purity. The method requires a small amount of sample of approximately 107EVs, limited handling of the sample and data analysis time in the order of minutes; it is fully automatable and can be applied to both crude and purified samples.

The over-the-scope clip (OTSC; Ovesco, Tübingen, Germany) is a novel endoscopic clipping device designed for tissue approximation. The device has been used in the closure of fistulas and perforations. We hereby report a series of patients with high-risk non-variceal upper gastrointestinal bleeding (NVUGIB) lesions in whom OTSCs were used as first-line endoscopic treatment. We prospectively collected and retrospectively analysed data over a period of 12 months from October 2013 to November 2014 from all consecutive patients who underwent emergency endoscopy for acute severe high-risk NVUGIB and were treated with OTSC as primary first-line therapy. We included forty consecutive patients with mean age 69 years (range 25–94 years). All patients were treated with the non-traumatic version of the OTSC system (23 with the 11 mm version and 17 with the 12 mm version). Indications for OTSC treatment included gastric ulcer with large vessel (Forrest IIa) (n= 8, 20 %), duodenal ulcer (Forrest Ib) (n= 7, 18 %), duodenal ulcer with large vessel (Forrest IIa) (n= 6, 15 %), Dieulafoy’s lesion (n= 6, 15 %) and other secondary indications (n= 13, 32 %). Technical success and primary haemostasis were achieved in all patients (100 %). No re-bleeding, need for surgical or radiological embolization treatment or other complications were observed during the follow-up period of 30 days. We conclude OTSC placement as a first-line endoscopic treatment seems to be effective, safe and easy to perform and should be considered in patients with high-risk NVUGIB lesions.

Some patients with benign colorectal obstruction do not respond to endoscopic balloon dilation. Fully covered self-expandable metal stents (FCSEMSs) have several potential advantages over non-covered stents, including a higher likelihood of retrieval owing to limited local tissue reaction. However, the efficacy and safety of FCSEMSs in benign colorectal strictures have not yet been established. Retrospective analysis of prospectively collected data concerning patients with post-surgical benign symptomatic anastomotic colorectal strictures, refractory to endoscopic dilation and in whom FCSEMSs had been placed at our center. Technical success was defined as successful stent placement and deployment at the stricture site. Early clinical success was defined as symptom relief persisting at least for 3 days. Follow-up was based on monthly clinical evaluation and quarterly endoscopic assessment. Endoscopic stent removal was planned on the basis of clinical or endoscopic assessment. Prolonged clinical success was defined as persistent symptom relief during follow-up. Technical and early clinical success were obtained in 16 of 16 (100 %) patients. The median follow-up was 21 months. Prolonged clinical success was achieved in 9/16 (56 %) cases. There was no major complication, including perforation and bleeding. Stent migration occurred in 3 (19 %) cases, in two of them associated with clinical failure. The median stent diameter was significantly higher in patients with successful than in those with unsuccessful clinical outcome (26 vs. 20 mm, P= 0.006). The clinical success rate was 1/6 (17 %) in patients who received a 20–22 mm stent and 8/10 (80 %) in those who received a 24–26 mm stent, respectively (P= 0.035). FCSEMSs can represent effective and safe treatment for refractory anastomotic colorectal strictures. Large diameter stents are warranted for better results.

Extracellular vesicles (EVs) are emerging as promising diagnostic and therapeutic tools for a variety of diseases. The characterization of EVs requires a series of orthogonal techniques that are overall time‐ and material‐consuming. Here, a microfluidic device is presented that exploits the combination of diffusion sizing and multiwavelength fluorescence detection to simultaneously provide information on EV size, concentration, and composition. The latter is achieved with the nonspecific staining of lipids and proteins combined with the specific staining of EV markers such as EV‐associated tetraspanins via antibodies. The device can be operated as a single‐step immunoassay thanks to the integrated separation and quantification of free and EV‐bound fluorophores. This microfluidic technique is capable of detecting and quantifying components associated to EV subtypes and impurities and thus to measure EV purity in a time scale of minutes, requiring less than 5 µL of sample and minimal sample handling before the analysis. Moreover, the analysis is performed directly in solution without immobilization steps. Therefore, this method can accelerate screening of EV samples and aid the evaluation of sample reproducibility, representing an important complementary tool to the current array of biophysical methods for EV characterization, particularly valuable for instance for bioprocess development. A crucial step to optimize large‐scale production of extracellular vesicles (EVs) is the development of characterization techniques capable of simultaneously monitoring physical and biochemical properties of EVs with high throughput. Here, a microfluidic technique is presented that can detect particle subpopulations, quantify their biomarkers, and measure their purity in a time scale of minutes and with no sample pretreatments.

SpyGlass®single-operator peroral cholangioscopy appears to be a promising technique to overcome some limitations of conventional peroral cholangioscopy. We aimed to prospectively evaluate the SpyGlass system in a cohort of patients with indeterminate biliary lesions.Patients with indeterminate strictures or filling defects at endoscopic retrograde cholangiopancreatography (ERCP) were consecutively enrolled. After SpyGlass visual evaluation, targeted biopsies were taken with the SpyBite®and histopathological assessment was made by two experienced gastrointestinal pathologists. SpyBite-targeted biopsy results were evaluated by assessing agreement with surgical specimens and by evaluation of final, clinical follow-up-based diagnosis.Fifty-two patients participated in the study. In 7 cases, definite diagnosis (stones, varices) was made by SpyGlass endoscopic evaluation. In 42 of the remaining 45 cases, material suitable for histopathology assessment was provided by the SpyBite. Overall, a definite diagnosis was made in 49 (7 + 42; 94 %) cases. Agreement of SpyBite biopsy results with surgical specimen diagnosis was found in 38/42 (90 %) cases; sensitivity, specificity, and positive and negative predictive values were 88, 94, 96, and 85 %, respectively. Procedure-related complications consisted of one case of mild cholangitis and one case of mild pancreatitis.In our series, the SpyGlass system allowed adequate biopsy sampling and definite diagnosis with high accuracy in the vast majority of patients with indeterminate biliary lesions. Its use was associated with a low complication rate. Further refinements of the technique are warranted, but the SpyGlass system has the potential to become a diagnostic standard for the assessment of indeterminate biliary lesions.

Pancreatic duct stent placement during endoscopic retrograde cholangiopancreatography (ERCP) has been recommended in patients at risk for post-ERCP pancreatitis. However, the optimal duration of stent placement remains an open question. Our aim was to compare the efficacy of pancreatic stenting for the duration of ERCP only with spontaneous dislodgment/deferred endoscopic removal in preventing post-ERCP pancreatitis after accidental wire-guided pancreatic duct cannulation.All patients in whom accidental wire-guided pancreatic duct cannulation had occurred during ERCP underwent immediate 5-Fr unflanged pigtail pancreatic duct stenting before attempting any other endoscopic maneuver. At the end of the ERCP, patients were randomly assigned to immediate stent removal (group A) or to leaving the stent in place (group B). Assessment of post-ERCP pancreatitis was blind.Post-ERCP pancreatitis occurred in 6/21 (29 %) patients in group A and in 0/19 patients in group B (P= 0.021); the two groups were well matched for their baseline characteristics. Post-ERCP pancreatitis was mild in two patients, moderate in two patients, and severe in two patients. Stents dislodged spontaneously in 14/19 (74 %) patients within 24–96 h; uneventful endoscopic removal was carried out after 96 h in 5 cases. Proximal stent migration did not occur in any case.Pancreatic duct stent placement for the duration of ERCP only does not prevent post-ERCP pancreatitis. Pancreatic stents should be left in place until spontaneous dislodgment occurs or endoscopic removal is deemed timely. 5-Fr unflanged pigtail stents remain in place for a period sufficient to prevent post-ERCP pancreatitis and do not migrate proximally.

Human neuroserpin (hNS) is a serine protease inhibitor that belongs to the serpin superfamily and is expressed in nervous tissues. The serpin fold is generally characterized by a long exposed loop, termed the reactive center loop, that acts as bait for the target protease. Intramolecular insertion of the reactive center loop into the main serpin β-sheet leads to the serpin latent form. As with other known serpins, hNS pathological mutants have been shown to accumulate as polymers composed of quasi-native protein molecules. Although hNS polymerization has been intensely studied, a general agreement about serpin polymer organization is still lacking. Here we report a biophysical characterization of native hNS that is shown to undergo two distinct conformational transitions, at 55°C and 85°C, both leading to distinct latent and polymeric species. The latent and polymer hNS forms obtained at 45°C and 85°C differ in their chemical and thermal stabilities; furthermore, the hNS polymers also differ in size and morphology. Finally, the 85°C polymer shows a higher content of intermolecular β-sheet interactions than the 45°C polymer. Together, these results suggest a more complex conformational scenario than was previously envisioned, and, in a general context, may help reconcile the current contrasting views on serpin polymerization.

Using the peptide hormone glucagon and Aβ(1–40) as model systems, we have sought to elucidate the mechanisms by which fibrils grow and multiply. We here present real-time observations of growing fibrils at a single-fibril level. Growing from preformed seeds, glucagon fibrils were able to generate new fibril ends by continuously branching into new fibrils. To our knowledge, this is the first time amyloid fibril branching has been observed in real-time. Glucagon fibrils formed by branching always grew in the forward direction of the parent fibril with a preferred angle of 35–40°. Furthermore, branching never occurred at the tip of the parent fibril. In contrast, in a previous study by some of us, Aβ(1–40) fibrils grew exclusively by elongation of preformed seeds. Fibrillation kinetics in bulk solution were characterized by light scattering. A growth process with branching, or other processes that generate new ends from existing fibrils, should theoretically give rise to different fibrillation kinetics than growth without such a process. We show that the effect of adding seeds should be particularly different in the two cases. Our light-scattering data on glucagon and Aβ(1–40) confirm this theoretical prediction, demonstrating the central role of fibril-dependent nucleation in amyloid fibril growth

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO2-PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegansas the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility.

Kinetics of human insulin aggregation has been studied at pH 1.6 and 60°C, when amyloid fibrils are formed. We developed a novel approach based on the analysis of scattered light intensity distribution, which allows distinguishing between small and large size aggregates. By this method, we observed an exponential growth of fibrillar aggregates implying a heterogeneous aggregation mechanism. Also, the apparent lag time observed, correlated with the major increase of thioflavin T fluorescence, has been assigned to the onset of large size cluster formation.

The importance of understanding the mechanism of protein aggregation into insoluble amyloid fibrils lies not only in its medical consequences, but also in its more basic properties of self-organization. The discovery that a large number of uncorrelated proteins can form, under proper conditions, structurally similar fibrils has suggested that the underlying mechanism is a general feature of polypeptide chains. In this work, we address the early events preceding amyloid fibril formation in solutions of zinc-free human insulin incubated at low pH and high temperature. Here, we show by time-lapse atomic force microscopy that a steady-state distribution of protein oligomers with a quasiexponential tail is reached within a few minutes after heating. This metastable phase lasts for a few hours, until fibrillar aggregates are observable. Although for such complex systems different aggregation mechanisms can occur simultaneously, our results indicate that the prefibrillar phase is mainly controlled by a simple coagulation-evaporation kinetic mechanism, in which concentration acts as a critical parameter. These experimental facts, along with the kinetic model used, suggest a critical role for thermal concentration fluctuations in the process of fibril nucleation.

Caustic strictures of the gastrointestinal tract are often difficult to treat, since relapses are frequent after medical or endoscopic treatment. Thus, novel approaches are needed. We report here our experience with self-expandable metallic stents (SEMS) as a new endoscopic approach in three patients with corrosive strictures of the upper gastrointestinal tract.