Multiscale texture descriptors for automatic small bowel tumors detection in capsule endoscopy

Conventional endoscopic exams do not allow the entire visualization of the gastrointestinal (GI) tract. Push enteroscopy (PE) is an effective diagnostic and therapeutic procedure, although it only allows exploration of the proximal small bowel (Pennazio et al., 1995). Simultaneously, convetional colonoscopy is limited at the terminal ileum. Therefore, prior to the wireless capsule endoscopy era, the small intestine was the conventional endoscopy’s last frontier, because it could not be internally visualized directly or in it’s entirely by any method (Herrerías & Mascarenhas-Saraiva, 2007). The small intestine accounts for 75% of the total length and 90% of the surface area of the gastrointestinal tract. In adults it measures about 570 cm at post mortem, which is substantially longer than conventional video endoscopes (100-180 cm) (Swain & Fritscher-Ravens, 2004). Intraoperative enteroscopy is the most complete but also the most invasive means of examining the small bowel (Gay et al., 1998). Given the technical and medical improvements introduced on the assessment of the gastrointestinal (GI) tract, Capsule Endoscopy (CE) is considered as the first major technological innovation in GI diagnostic medicine since the flexible endoscope (Kaffes, 2009). More recently, a new technique, the double-balloon enteroscopy (DBE), has been introduced into clinical practice (Yamamoto & Kita, 2006). DBE has the potential to examine the entire length of the small bowel with biopsy and therapeutic capability. Nevertheless, it is a time consuming procedure that requires specialist training for the operating physician. We should note that DBE and CE are complementary tools and not competitive (Chen et al., 2007). Hence, the diagnostic ease of CE can be complemented with a targeted and often therapeutic DBE (Kaffes, 2009). Therefore, CE can be used as a first line diagnosis method, while DBE can be used as a confirmatory or therapeutic modality for lesions first visualized by CE (Pennazio, 2006). The endoscopic capsule is a pill-like device, with only 11mm x 26 mm, and includes a miniaturized camera, a light source and circuits for the acquisition and wireless transmission of signals (Iddan et al., 2000). As the capsule moves through GI tract, propelled exclusively by peristalsis, it acquires images at a rate of two per second and sends them to a hard disk receiver that is worn in the belt of the patient, in a wireless communication scheme. The acquisition of images is limited by the battery life of the device, usually around eight hours, which imply that in a single CE exam more than 50000 images are acquired. If no complications arise, the capsule should be in the patient’s stool, usually within 24-48 h, and not reused (Pennazio, 2006). Capsule endoscopy has evolved in a few short years to become a first-line, noninvasive diagnostic technique for the small bowel. CE is now being utilized worldwide to assess patients for obscure gastrointestinal bleeding, possible Crohn’s disease, celiac disease and small bowel tumors (Lee & Eisen, 2010). It is now available in over 4500 practice sites around the world (Munoz-Navas, 2009). The time required to a physician to analyze the resulting video is, on average, 40-60 min (Pennazio, 2006). The reading time and interpretation of CE exams is very time consuming given that more than 50,000 images have to be reviewed (Delvaux & Gay, 2006; Mergener et al., 2007), which contributes to the high cost of a CE exam (Westerhof et al., 2009). Thus, a computer assisted diagnosis tool to help the physicians to evaluate CE exams faster and more accurately is an important technical challenge and an excellent economical opportunity.Centre Algoritm

Probiotic potential of fructo-oligosaccharides produced by Aspergillus ibericus

The gastrointestinal tract harbours a diverse and dynamic microbial community that directly impacts human health. Prebiotics, such as fructo-oligosaccharides (FOS), play a crucial role in the modulation of colonic microbiota, reducing pathophysiological disorders and associated chronic diseases. The prebiotic potential of FOS produced by a newly isolated strain Aspergillus ibericus was studied. FOS fermentability by the probiotic Lactobacillus rhamnosus was evaluated. L. rhamnosus was grown in de Man-Rogosa-Sharpe (MRS) broth, with different carbon sources: glucose (positive control), no sugar (negative control), microbial-derived FOS from A. ibericus and Raftilose®P95, a non-microbial commercial FOS sample (from Beneo-Orafti, Belgium). A final concentration of 2 % (w/v) in sugar was used. Fermentation was carried out in a 96-well microplate and a shake flask, for 24 h, at 37 ºC, with an agitation of 120 rpm. Biomass growth was analysed by optical density at 620 nm. The consumption of sugars and the production of short chain fatty acids (SCFA) and lactate was quantified by HPLC. Maximum cell growth was reached at approximately 12 h, for all carbon sources. The highest growth was achieved for glucose samples, followed by the microbial-derived FOS, then Raflitose and finally the negative control. Although the microbial-derived FOS promoted great cellular growth, only kestose (GF2), together with residual amounts of glucose and sucrose presented in the sample, were consumed. This may explain the two different slopes exhibited during the exponential phase growth. Most likely hypothesis is that probiotic bacteria was cleaving GF2 in the first hours of fermentation, using only the smallest sugars present for growing. And Nystose (GF3) and fructofuranosylnystose (GF4) were not consumed, even when prolonging the fermentation up to 48 h. SCFA identified were valerate and propionate, as well as succinate, formate, acetate, iso-butyrate and nbutirate, although in lower amount. Higher amount of SCFA and lactate were determined while growing in the microbial-derived FOS, as compared to the commercial sample. Overall, lactate was the main metabolite produced during the fermentations. In conclusion, the prebiotic potential of microbial-derived FOS synthesized by A. ibericus was demonstrated, providing promising indication of its usability as food ingredient with strong prebiotic features.info:eu-repo/semantics/publishedVersio

How prebiotics have been produced from agro-industrial waste: an overview of the enzymatic technologies applied and the models used to validate their health claims

Background The disposal of waste from the food industry represents a major environmental concern. Nonetheless, agro-industrial by-products can be enzymatically converted into low-cost high-value-added products, such as prebiotics, while contributing to a circular economy. As a first approach for health claims validation of these novel products, several gastrointestinal models have been used. Scope and approach The main objective of this review is to provide a comprehensive overview of the advances in the enzymatic technologies applied to the production of prebiotics from agro-industrial wastes. The strategies used in the conversion of the wastes, including pre-treatment processes, type of enzymes applied, and the reaction conditions used are revised. Finally, from data obtained by in vivo trials and in vitro gastrointestinal simulation, the functionality of the produced prebiotics and their biological mechanisms of action are discussed. Key findings and conclusions Enzymatic processes have proven their efficiency for the conversion of low-cost agro-industrial wastes into commercial valuable compounds, such as prebiotics. Still, the potential of enzymes for the bioconversion of the vast diversity of existing wastes has yet to be explored. By researching different setups of the enzymatic reaction and optimization of the reaction conditions, greater yields of the prebiotic extraction or synthesis may be achieved. Also, despite the many available gastrointestinal models, few studies have been done on the biological function of the prebiotics obtained from agro-industrial wastes, which has been a drawback in the validation of health claims associated with these novel products.Daniela Gonçalves, Dalila Roupar, and Abigail González acknowledge the Portuguese Foundation for Science and Technology (FCT) for the PhD grants (2022.11590.BD, SFRH/BD/139884/2018, and 2021.06268.BD, respectively). Clarisse Nobre acknowledges FCT for the Assistant Research contract 2021.01234.CEECIN. This study was supported by the FCT under the scope of the strategic funding of UIDB/04469/2020 unit and by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020. Also by the project cLabel+ (POCI-01-0247-FEDER-046080) co-financed by Compete 2020, Lisbon 2020, Portugal 2020, and the European Union, through the European Regional Development Fund (ERDF), as well as the project AgriFood XXI (NORTE-01-0145-FEDER-000041), under the ERDF through the Competitiveness factors Operational program – Norte 2020, COMPETE and by National Funds through the FCT.info:eu-repo/semantics/publishedVersio

OC33 Chromatographic approaches to study pine nut skin: exploitation of its composition and bioactivities

Pine nut skin (PNS) is an unexploited and uncharacterized by-product recovered during pine nut processing. The exploitation of by-products as sources of valuable compounds agrees with the current demand for the reduction of waste, and a transition to more sustainable production and consumption1. Therefore, PNS characterization and bioactive potentialities were assessed. The utilization of several chromatographic techniques allowed the characterization of PNS phenolic compounds (HPLC-DAD-UV and HPLC-DAD-ESI-MSn), and the carbohydrates quantification and structural characterization, after specific derivatization (GC-FID and GC-MS). PNS subcritical water extraction using microwave was optimized and the obtained extracts, separated into low-molecularweight (rich in phenolic compounds) and high-molecular-weight (rich in carbohydrates), were evaluated regarding their digestibility and prebiotic activity. The prebiotic potential was assessed by quantifying the short-chain fatty acids (HPLC-UV) produced after the in vitro faecal fermentation. HPLC-DAD-ESI-MSn allowed to identify PNS phenolic compounds, namely protocatechuic, p-coumaric, and caffeic acids, while HPLC-DAD-UV enabled the monomers identification of proanthocyanidins ((epi)catechins) and hydrolysable tannins (protocatechuic acid), after acid methanolysis. GC techniques allowed to disclose the polysaccharides structures (xyloglucans and pectic polysaccharides) and their degradation by microbiota. The fermentation of both extracts rich in phenolic compounds and rich in polysaccharides resulted in an increased production of acetic, propionic, and butyric acids when compared to the commercial prebiotic inulin, proposing these PNS extracts as prebiotic agents.The work was supported through the projects UIDB/50006/2020 and UIDP/50006/2020, funded by FCT/MCTES through national funds. Soraia P. Silva, Alondra González and Dalila Roupar thank FCT/MCTES and ESF through NORTE 2020 for their PhD grants (ref. SFRH/BD/136471/2018, SFRH/BD/06268/2021 and SFRH/DB/139884/2018 respectively). Elisabete Coelho thanks the research contract (CDL-CTTRI-88-ARH/2018 – REF. 049-88-ARH/2018) funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Clarisse Nobre acknowledges FCT for the assistant research contract 2021.01234.CEECIND.info:eu-repo/semantics/publishedVersio

Prebiotic potential of fructo-oligosaccharides produced by aspergillus ibericus in a bacterial community representative of the gut microbiota

Introduction The positive effects of prebiotics on human health are associated to their capacity to modulate gut microbiota and consequently, regulate the production of metabolites, such as the short-chain fatty acids (SCFA). Herein, the prebiotic potential of microbial-fructo-oligosaccharides (microbial-FOS) produced by a co-culture of Aspergillus ibericus and Saccharomyces cerevisiae YIL162W [1] was evaluated in a designed bacterial consortium representing the healthy human gut microbiota. Methodology The prebiotic effect of the microbial-FOS was compared with two non-microbial commercial inulin-type samples: Raftilose®P95 and Frutalose®OFP. The bacterial consortium was composed by Bacteroides dorei, Bacteroides vulgatus, Bifidobacterium adolescentis, Bifidobacterium longum, Escherichia coli, Lactobacillus acidophilus, and Lactobacillus rhamnosus at a similar phyla proportion as found in the human colon. Fermentations were run for 30 h in FEED media [2]. During fermentation, the pH, bacterial growth (monitored by optical density measurement and selective media inoculation), SCFA production and sugar consumption (assessed by HPLC) were evaluated. Results and Discussion Bacterial growth decreased in the following order: glucose > microbial-FOS > Raftilose® P95 > Frutalose® OFP. Microbial-FOS stimulated a higher Bifidobacterium and Lactobacillus probiotic strains growth, as compared with other samples. The E. coli growth was suppressed at the beginning of fermentation, probably due to a pH reduction caused by lactate produced by Lactobacillus. Lactate and SCFA (such as acetate, propionate, and butyrate) were produced using all samples. The microbial-FOS sample (initial concentration: 20 g/L) produced the highest amount of lactate (12.2±0.1 g/L) and SCFA (4.0±0.1 g/L). The bacterial consortium seems to consume preferentially microbial-FOS presenting higher degree of polymerization (consumption: 60.8±0.1 % GF4 (1- fructofuranosyl nystose); 57.2±0.1 % GF3 (nystose); 49.6±0.1 % GF2 (kestose)). Conclusions Microbial-FOS were successfully used as a substrate by a microbiota bacterial consortium. Also, microbial-FOS stimulated higher Bifidobacterium and Lactobacillus growth as well as higher total SCFA and lactate concentrations among the other substrates studied. The prebiotic potential of microbial-FOS produced by A. ibericus was demonstrated, providing a promising indication of its usability as a food ingredient with strong prebiotic features.info:eu-repo/semantics/publishedVersio

Fermentability of fructo-oligosaccharides produced by Aspergillus ibericus by human gut microflora

Fructo-oligosaccharides (FOS) are a well-known class of prebiotics which selectively stimulate the growth of bifidobacteria in the gut. Although FOS occurs naturally in many fruits and vegetables, its content is low and are season-limited. As an alternative, we have identified a new isolated strain of Aspergillus ibericus as a good FOS producer. To increase FOS content in the mixture and decrease the amount of non-prebiotic sugars released during fermentation, FOS were produced using an integrated fermentation strategy. A co-culture of A. ibericus with a Saccharomyces cerevisiae YIL162W was used, for simultaneous FOS production and purification by each strain, respectively. In the present work, the functionality of the FOS produced by A. ibericus as a prebiotic was assessed. FOS prebiotic potential was evaluated in anaerobic batch cultures for 24 h. Human faeces from 5 healthy volunteer individuals were used. With the faecal inoculum, several carbon sources were tested, namely a commercial FOS sample derived from inulin - Raftilose® P95 from Beneo-Orafti, Belgium and the FOS samples produced by the aforementioned A. ibericus. The dynamic bacterial populations changes were assessed by PCR-real time, as well as the production of short chain fatty acids (SCFA) and lactate quantified through analytical methods (HPLC). Both carbon sources were compared for their prebiotic potential. A bifidogenic effect was observed for both microbial and commercial FOS. The growth of lactobacilli probiotic strains was similar for both FOS substrates. Thus, the microbial FOS triggered a beneficial effect on gut microbiota composition. SCFA including succinate, acetate, propionate and valerate - were produced by the five faecal inoculum tested, at high concentrations using both substrates. Lower amount of formate and butyrate were also produced. Despite similar trends between both FOS substrates, a tendency for an earlier increase on SCFA concentrations in the culture was found for the microbial FOS, potentially indicating a faster metabolization rate. Nonetheless, microbial FOS seems to have similar prebiotic potential when compared to commercial FOS samples, potentially indicating a feasible route for bio-based FOS production. In conclusion, microbial FOS exhibited promising potential as nutraceutical ingredients for gut microbiota modulation with likely prebiotic features.info:eu-repo/semantics/publishedVersio

Modulation of designed gut bacterial communities by prebiotics and the impact of their metabolites on intestinal cells

The impact of prebiotics on human health is associated with their capacity to modulate microbiota, improving beneficial microbiota–host interactions. Herein, the prebiotic potential of microbial-fructo-oligosaccharides (microbial-FOSs) produced by a co-culture of Aspergillus ibericus plus Saccharomyces cerevisiae was evaluated on seven- and nine-strain bacterial consortia (7SC and 9SC, respectively), designed to represent the human gut microbiota. The 7SC was composed of Bacteroides dorei, Bacteroides vulgatus, Bifidobacterium adolescentis, Bifidobacterium longum, Escherichia coli, Lactobacillus acidophilus, and Lactobacillus rhamnosus. The 9SC also comprised the aforementioned bacteria, with the addition of Bacteroides thetaiotaomicron and Roseburia faecis. The effect of microbial-FOSs on the metabolic activity of intestinal Caco-2/HT29-MTX-E12 co-culture was also assessed. The results showed that microbial-FOS selectively promoted the growth of probiotic bacteria and completely suppressed the growth of E. coli. The microbial-FOSs promoted the highest production rates of lactate and total short-chain fatty acids (SCFA) as compared to the commercial prebiotic Frutalose® OFP. Butyrate was only produced in the 9SC consortium, which included the R. faecis—a butyrate-producing bacteria. The inclusion of this bacteria plus another Bacteroides in the 9SC promoted a greater metabolic activity in the Caco-2/HT29-MTX-E12 co-culture. The microbial-FOSs showed potential as promising prebiotics as they selectively promote the growth of probiotic bacteria, producing high concentrations of SCFA, and stimulating the metabolic activity of gut cells.Dalila Roupar: Abigail González, and Daniela A. Gonçalves acknowledge the Portuguese Foundation for Science and Technology (FCT) for their PhD Grants SFRH/DB/139884/2018, 2021.06268.BD and 2022.11590.BD, respectively. Clarisse Nobre and Joana T. Martins acknowledge FCT for the Assistant Research Contract 2021.01234.CEECIND and 2022.00788.CEECIND, respectively. This study was supported by the FCT under the scope of the strategic funding of UIDB/04469/2020 unit by LABBELS—Associate Laboratory in Biotechnology, Bioengineering, and Microelectromechanical Systems, LA/P/0029/2020—and by the Project ColOsH PTDC/BTM–SAL/30071/2017.info:eu-repo/semantics/publishedVersio

Modulation of the Gut Microbiota by Tomato Flours Obtained after Conventional and Ohmic Heating Extraction and Its Prebiotic Properties

Several studies have supported the positive functional health effects of both prebiotics and probiotics on gut microbiota. Among these, the selective growth of beneficial bacteria due to the use of prebiotics and bioactive compounds as an energy and carbon source is critical to promote the development of healthy microbiota within the human gut. The present work aimed to assess the fermentability of tomato flour obtained after ohmic (SFOH) and conventional (SFCONV) extraction of phenolic compounds and carotenoids as well as their potential impact upon specific microbiota groups. To accomplish this, the attained bagasse flour was submitted to an in vitro simulation of gastrointestinal digestion before its potential fermentability and impact upon gut microbiota (using an in vitro fecal fermentation model). Different impacts on the probiotic strains studied were observed for SFCONV promoting the B. animalis growth, while SFOH promoted the B. longum, probably based on the different carbohydrate profiles of the flours. Overall, the flours used were capable of functioning as a direct substrate to support potential prebiotic growth for Bifidus longum. The fecal fermentation model results showed the highest Bacteroidetes growth with SFOH and the highest values of Bacteroides with SFCONV. A correlation between microorganisms’ growth and short-chain fatty acids was also found. This by-product seems to promote beneficial effects on microbiota flora and could be a potential prebiotic ingredient, although more extensive in vivo trials would be necessary to confirm this

Segmentation of small bowel tumor tissue in capsule endoscopy images by using the MAP algorithm

State of the art algorithms for diagnosis of the small bowel by using capsule endoscopic images usually rely on the processing of the whole frame, hence no segmentation is usually required. However, some specific applications such as three-dimensional reconstruction of the digestive wall, detection of small substructures such as polyps and ulcers or training of young medical staff require robust segmentation. Current state of the art algorithms for robust segmentation are mainly based on Markov Random Fields (MRF) requiring prohibitive computational resources not compatible with applications that generate a great amount of data as is the case of capsule endoscopy. However context information given by MRF is not the only way to improve robustness. Alternatives could come from a more effective use of the color information. This paper proposes a Maximum A Posteriori (MAP) based approach for lesion segmentation based on pixel intensities read simultaneously in the three color channels. Usually tumor regions are characterized by higher intensity than normal regions, where the intensity can be measured as the vectorial sum of the 3 color channels. The exception occurs when the capsule is positioned perpendicularly and too close to the small bowel wall. In this case a hipper intense tissue region appears at the middle of the image, which in case of being normal tissue, will be segmented as tumor tissue. This paper also proposes a Maximum Likelihood (ML) based approach to deal with this situation. Experimental results show that tumor segmentation becomes more effective in the HSV than in the RGB color space where diagonal covariance matrices have similar effectiveness than full covariance matrices.info:eu-repo/semantics/publishedVersio