Conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLNAs) have gained significant attention due to their anticarcinogenic and lipid/energy metabolism-modulatory effects. However, their ...concentration in foodstuffs is insufficient for any therapeutic application to be implemented. From a biotechnological standpoint, microbial production of these conjugated fatty acids (CFAs) has been explored as an alternative, and strains of the genera
,
, and
have shown promising producing capacities. Current screening research works are generally based on direct analytical determination of production capacity (e.g., trial and error), representing an important bottleneck in these studies. This review aims to summarize the available information regarding identified genes and proteins involved in CLA/CLNA production by these groups of bacteria and, consequently, the possible enzymatic reactions behind such metabolic processes. Linoleate isomerase (LAI) was the first enzyme to be described to be involved in the microbiological transformation of linoleic acids (LAs) and linolenic acids (LNAs) into CFA isomers. Thus, the availability of
gene sequences has allowed the development of genetic screening tools. Nevertheless, several studies have reported that LAIs have significant homology with myosin-cross-reactive antigen (MCRA) proteins, which are involved in the synthesis of hydroxy fatty acids, as shown by hydratase activity. Furthermore, it has been suggested that CLA and/or CLNA production results from a stress response performed by the activation of more than one gene in a multiple-step reaction. Studies on CFA biochemical pathways are essential to understand and characterize the metabolic mechanism behind this process, unraveling all the gene products that may be involved. As some of these bacteria have shown modulation of lipid metabolism
, further research to be focused on this topic may help us to understand the role of the gut microbiota in human health.
Background
Abnormal motility patterns in the jejunum can be detected in patients with prominent colonic content, and these abnormalities may be due to either a primary jejunal dysfunction or a reflex ...distortion. The objective of the present study was to determine the effect of colonic distension on small bowel postprandial motility using high‐resolution manometry.
Methods
Single center, controlled, parallel, randomized, single blind study in healthy subjects testing the effect of colonic filling vs sham infusion on the responses to a meal in 16 healthy subjects. Nutrients were continuously infused in the proximal jejunum (2 Kcal/min) during the 2‐h study period to induce a steady‐state postprandial motor pattern. Jejunal motility was measured by water‐perfused, high‐resolution manometry. After 1 h postprandial recording (basal period), gas was infused during 7.5 min via a rectal tube (720 mL or sham infusion), and jejunal motility was recorded for another hour.
Key Results
Jejunal postprandial motility during the basal period was characterized by two overlapping components: a) continuous segmental activity (non‐propagated or shortly propagated) and b) intercurrent propagated fronts (3.8 ± 1.1 fronts of 2‐5 clustered contractions/h >10 cm propagation). As compared to sham infusion, colonic gas filling: a) inhibited continuous segmental contractile activity (by 17 ± 4%; p = 0.044 vs control group) and b) stimulated intermittent propagated fronts (up to 9.0 ± 2.2 fronts/h; p = 0.017 vs control group).
Conclusions and Inferences
Long retrograde reflexes induced by colonic distension distort the balance between segmental and propagated activity, and may affect the normal response of the jejunum to food ingestion. Jejunal manometry in patients may be artifacted by colonic overload.
Colonic filling with gas stimulated intermittent propagated fronts in the jejunum; hence, mild colonic distension induces long‐distance retrograde reflexes that alter normal postprandial small bowel motility.
Background
Our aim was to determine the reliability of plain abdominal radiographs for the evaluation of abdominal gas content in patients with functional digestive symptoms.
Methods
Abdominal CT ...scan scout views, mimicking a conventional plain abdominal radiograph, were obtained from 30 patients both during episodes of abdominal distension and basal conditions. Physicians (n = 50) were instructed to rate the estimated volume of gas in the 60 images presented in random sequence using a scale graded from 0 to ≥600 ml.
Key Results
The gas volumes estimated in the scout views differed from those measured by CT by a median of 90 (95% CI 70–102) ml, and the misestimation was not related to the absolute volume in the image. The accuracy of the observers, measured by their mean misestimation, was not related to their specialty or the training status (misestimation by 96 (95% CI 85–104) ml in staff vs 78 (70–106) ml in residents; p = 0.297). The accuracy was independent of the order of presentation of the images. Gas volume measured by CT in the images obtained during episodes of abdominal distension differed by a median of 39 (95% CI 29–66) ml from those during basal conditions, and this difference was misestimated by a median of 107 (95% CI 94–119) ml. The accuracy of these estimations was not related to the absolute gas volumes (R = −0.352; p < 0.001) or the magnitude of the differences.
Conclusions & Inferences
Plain abdominal radiographs have limited value for the evaluation of abdominal gas volume in patients with functional gut disorders.
Example of three‐dimensional reconstruction of abdominal CT scan showing intestinal gas. Plain AP projection (scout view) of the same scan. Relation between objective values of intestinal gas, measured by a validated CT technique in patients with functional gut disorders, and the subjective estimation of gas volumes on plain AP projection of the same CT scans (scout views) by 48 physicians. Individual estimations of 60 images are shown. CONCLUSION: The volumes of abdominal gas were grossly misestimated in the scout views, indicating that plain abdominal radiographs have no value for the evaluation of intestinal gas volume in patients with functional gut disorders.
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare mitochondrial disease caused by mutations in TYMP, encoding thymidine phosphorylase. Clinically it is characterized by severe ...gastrointestinal dysmotility associated with cachexia and a demyelinating sensorimotor polyneuropathy. Even though digestive manifestations are progressive and invariably lead to death, the features of gastrointestinal motor dysfunction have not been systematically evaluated. The objective of this study was to describe gastrointestinal motor dysfunction in MNGIE using state-of-the art techniques and to evaluate the relationship between motor abnormalities and symptoms.
Prospective study evaluating gastrointestinal motor function and digestive symptoms in all patients with MNGIE attended at a national referral center in Spain between January 2018 and July 2022.
In this period, five patients diagnosed of MNGIE (age range 16-46 years, four men) were evaluated. Esophageal motility by high-resolution manometry was abnormal in four patients (two hypoperistalsis, two aperistalsis). Gastric emptying by scintigraphy was mildly delayed in four and indicative of gastroparesis in one. In all patients, small bowel high-resolution manometry exhibited a common, distinctive dysmotility pattern, characterized by repetitive bursts of spasmodic contractions, without traces of normal fasting and postprandial motility patterns. Interestingly, objective motor dysfunctions were detected in the absence of severe digestive symptoms.
MNGIE patients exhibit a characteristic motor dysfunction, particularly of the small bowel, even in patients with mild digestive symptoms and in the absence of morphological signs of intestinal failure. Since symptoms are not predictive of objective findings, early investigation is indicated.
Dinópolis, in the province of Teruel (Spain), offers a network of facilities which attract many palaeontology and dinosaur enthusiasts. It promotes a symbiosis between a palaeontological museum, a ...territorial network of interpretation centres and a set of attractions whose main protagonists are dinosaurs. All that is complemented by the implementation of public programs that shape the intangible heritage of the project. Dinópolis brings together two institutions: a Foundation, granted as a monographic museum of Palaeontology and a Managing Society, in charge of managing the spaces open to the public. The aim of the Foundation is to preserve and popularize the palaeontological resources after their research. The Managing Society promotes Dinópolis and all the complementary tourist services as well as the leisure facilities. In order to fulfil its objectives, Dinópolis has a large palaeontological park in the city of Teruel and seven smaller museums that foster visits around the province. These “satellites” show a selection of local fossils as well as the palaeontological techniques followed by its researchers. The headquarters house fossil collections, palaeontology laboratories, research areas and two modern buildings with up-to-date fossil exhibitions. It also offers dark-rides, theatre shows and open-air activities. The purpose of these facilities and public programs is to boost geotourism in rural areas. This would contribute to mitigate depopulation, a dramatic process that has been continuously affecting the province for more than a century. With Dinópolis, the palaeontological resources are applied to a regional development project based on scientific leisure. The need to improve the quality of life for the inhabitants of Teruel and revitalize their economy, was precisely the trigger that motivated the creation of this model of development. Its greatest merit is to be a model of growth which puts together research and leisure facilities, and has generated more than 2.7 million visits since its opening in 2001. Keywords:: palaeontological facilities, rural development, scientific heritage, geotourism, depopulation
During many years, the milk fat has been unfairly undervalued due to its association with higher levels of cardiovascular diseases, dyslipidaemia or obesity, among others. However, currently, this ...relationship is being re-evaluated because some of the dairy lipid components have been attributed potential health benefits. Due to this, and based on the increasing incidence of cancer in our society, this review work aims to discuss the state of the art concerning scientific evidence of milk lipid components and reported anticancer properties. Results from the
and
experiments suggest that specific fatty acids (FA) (as butyric acid and conjugated linoleic acid (CLA), among others), phospholipids and sphingolipids from milk globule membrane are potential anticarcinogenic agents. However, their mechanism of action remains still unclear due to limited and inconsistent findings in human studies.
Introduction
Minute rhythm and prolonged simultaneous contractions are patterns of postprandial small bowel contractile activity that historically have been considered as suggestive of mechanical ...intestinal obstruction; however, these patterns have been also encountered in patients with motility‐like symptoms in the absence of bowel obstruction. The objective of this study was to determine the current diagnostic outcome of patients with these intestinal manometry patterns.
Methods
Retrospective study of patients with chronic digestive symptoms evaluated by intestinal manometry at our center between 2010 and 2018.
Results
The minute rhythm (MRP) or prolonged simultaneous contractions (PSC) postprandial patterns were detected in 61 of 488 patients (55 MRP and 6 PSC). Clinical work‐up detected a previously non‐diagnosed partial mechanical obstruction of the distal intestine in 10 (16%) and a systemic disorder causing intestinal neuropathy in 32 (53%). In the remaining 19 patients (31%, all with MRP), the origin of the contractile pattern was undetermined, but in 16, substantial fecal retention was detected within 7 days of the manometric procedure by abdominal imaging, and in 6 of them colonic cleansing completely normalized intestinal motility on a second manometry performed within 39 ± 30 days.
Conclusion and Inference
Currently, the most frequent origin of MRP and PSC encountered on small bowel manometry is intestinal neuropathy, while a previously undetected mechanical obstruction is rare. Still, in a substantial proportion of patients, no underlying disease can be identified, and in them, colonic fecal retention might play a role, because in a subgroup of these patients, manometry normalized after colonic cleansing. Hence, colonic preparation may be considered prior to intestinal manometry.
Minute rhythm (or clustered contractions) in postprandial small bowel manometry can be produced by intestinal neuropathy or mechanical occlusion, but in some patients, the minute rhythm pattern is associated with colonic fecal retention, and resolves after colonic cleansing. Hence, colonic preparation may be considered prior to intestinal manometry.
Background
The last version of the Chicago Criteria for high resolution esophageal manometry proposes an expanded protocol including complementary maneuvers to improve the diagnostic yield of the ...exploration. Our aim was to determine the diagnostic gain of the CCv4.0 protocol compared to the CCv3.0 protocol.
Methods
All manometry recordings performed in 4 reference centers during the first 10 months after the implementation of the new protocol were retrospectively reviewed. The time spent to complete the protocol was measured, and the changes in diagnosis resulting from the new CCv4.0 were compared to CCv3.0.
Key Results
From a total of 756 HRM performed, 606 studies could be properly analyzed. The duration of the studies was 18.3 ± 4.3 min. From these, 11.3 ± 3.4 min were spent to complete the CCv3.0 protocol, and 7.4 ± 3.6 min were spent for the remaining maneuvers. A discordant diagnosis between CCv3.0 and CCv4.0 was obtained in 12% of patients: 32% of patients with ineffective esophageal motility turned to normal motility; 24% of patients with esophagogastric junction outlet obstruction (EGJOO) turned to a non‐obstructive disorder; and 1% of patients with an apparently normal EGJ relaxation, turned to an obstructive disorder. EGJOO according to CCv4.0 was more prevalent in patients referred for dysphagia (11%) than those referred for GERD (4%; p = 0.003).
Conclusions and Inferences
Prolongation of the time spent to complete the CCv4.0 protocol leads to a change in the diagnosis of 12% of patients. Clinically relevant changes are mainly related to the evaluation of EGJOO.
The new protocol of HRM recommended by CC4.0. prolongs the exploration by 7 ± 4 min, and produces a change in the final diagnosis in 12% on patients, mainly an increment in normal motility, and a reduction in ineffective esophageal motility, and esophagogastric junction outlet obstruction.
Current research on lipids is highlighting their relevant role in metabolic/signaling pathways. Conjugated fatty acids (CFA), namely isomers of linoleic and linolenic acid (i.e. CLA and CLNA, ...respectively) can positively modulate inflammation processes and energy metabolism, promoting anti-carcinogenic and antioxidant effects, improved lipid profiles and insulin resistance, among others. Bioactive doses have been indicated to be above 1 g/d, yet these cannot be achieved through a moderate intake (i.e. 1-2 servings) of natural sources, and certain CLA-containing products have limited commercial availability. Such handicaps have fueled research interest in finding alternative fortification strategies. In recent years, screening of dairy products for CFA-producing bacteria has attracted much attention and has led to the identification of some promising strains, including Bifidobacterium breve NCIMB 702258. This strain has shown interesting producing capabilities in model systems as well as positive modulation of lipid metabolism activities in animal studies. Accordingly, the aim of this research work was to assay B. breve NCIMB 702258 in semi-skimmed milk to produce a probiotic fermented dairy product enriched in bioactive CLA and CLNA. The effect of substrates (LA, α-LNA and γ-LNA) on growth performance and membrane fatty acids profile was also studied, as these potential modifications have been associated to stress response. When tested in cys-MRS culture medium, LA, α-LNA and γ-LNA impaired the fatty acid synthesis by B. breve since membrane concentrations for stearic and oleic acids decreased. Variations in the C18:1 c11 and lactobacillic acid concentrations, may suggest that these substrates are also affecting the membrane fluidity. Bifidobacterium breve CFA production capacity was first assessed in cys-MRS with LA, α-LNA, γ-LNA or all substrates together at 0.5 mg/mL each. This strain did not produce CFA from γ-LNA, but converted 31.12% of LA and 68.20% of α-LNA into CLA and CLNA, respectively, after incubation for 24 h at 37 °C. In a second phase, B. breve was inoculated in a commercial semi-skimmed milk with LA, α-LNA or both at 0.5 mg/mL each. Bifidobacterium breve revealed a limited capacity to synthesize CLA isomers, but was able to produce 0.062-0.115 mg/mL CLNA after 24 h at 37 °C. However, organoleptic problems were reported which need to be addressed in future studies. These results show that although CFA were produced at too low concentrations to be able to achieve solely the bioactive dose in one daily portion size, fermented dairy products are a suitable vector to deliver B. breve NCIMB 702258.
The objective of this work was to investigate the effect of stress conditions frequently encountered in food-associated environments on virulence-associated characteristics of eight strains of ...Listeria monocytogenes. Strains were grown at low (11 °C, cold stress) and optimal (37 °C) temperatures and in high NaCl concentrations (6% NaCl, 11 °C; cold-osmotic stress) and tested for their ability to invade the human intestinal epithelial Caco-2 cells. Results demonstrate that the correlation between exposure to cold stress and increased invasion phenotype is strain-dependent as strains investigated exhibited different behaviours, i.e. exposure to cold stress conditions resulted in a significant increase of invasion levels in five out of the eight strains tested, when compared to growth under optimal conditions. On the other hand, when these cold-adapted cells were subsequently submitted to high salt concentrations and low temperature, their enhanced ability to invade Caco-2 was lost. Surprisingly, saturated fatty acids (SFA) and branched chain fatty acids (BCFA) decreased when L. monocytogenes were exposed to stress conditions as opposed to what has been observed in other studies, therefore highlighting that further studies will need to deepen in the understanding of the lipid metabolism of these strains. The effect of stress conditions on the survival of three selected L. monocytogenes strains through an in vitro gastrointestinal (GI) tract digestion model was further investigated. The exposure to cold-osmotic stress increased the survival of one strain through the GI tract.
•Stress conditions on virulence traits of L. monocytogenes investigated.•Growth at 11 °C resulted in a significant increase of invasiveness in five strains.•Correlation between cold stress and increased invasiveness was strain-dependent.•Subsequent exposure to cold-osmotic stress resulted in reduced invasiveness.•SFA and BCFA decreased when L. monocytogenes were exposed to stress conditions.
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