scholarly journals Application of selective extraction to the study of iron species present in diet and rat gastrointestinal tract contents

1992 ◽  
Vol 67 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Robert J. Simpson ◽  
Sanjiv Sidhar ◽  
Timothy J. Peters

Iron speciation in rodent diet and rat gastrointestinal tract lumen during dietary digestion and absorption was investigated with a novel selective extraction technique. Five Fe fractions were identified, namely exchangeable (soluble in 1 M-magnesium chloride), carbonate-bound (soluble in mild acid), oxide-bound (soluble in hydroxylamine–acetic acid), organic-bound (soluble after treatment with peroxide in nitric acid) and residual. Fe from the pelleted diet was mobilized by rat stomach to the exchangeable fraction, then redistributed to the carbonate- and oxide-bound fractions on passage through the proximal small intestine. In vitro incubation of diet with hydrochloric acid failed to mimic the in vivo effect of the stomach. In vitro neutralization of stomach contents with bicarbonate was found to produce a similar effect on Fe speciation to that seen when diet passed the proximal small intestine in vivo. Comparison of59Fe speciation in extrinsically labelled diet with endogenous Fe speciation showed that extrinsic labelling does not uniformly label all endogenous species. The experiments suggest that selective extraction may provide a useful approach to the study of Fe species present in diets, in vitro digestions and gastrointestinal contents.

2020 ◽  
Vol 124 (6) ◽  
pp. 567-576 ◽  
Author(s):  
Anna M. E. Hoogeveen ◽  
Paul J. Moughan ◽  
Edward S. de Haas ◽  
Paul Blatchford ◽  
Warren C. McNabb ◽  
...  

AbstractDietary fibre fermentation in humans and monogastric animals is considered to occur in the hindgut, but it may also occur in the lower small intestine. This study aimed to compare ileal and hindgut fermentation in the growing pig fed a human-type diet using a combined in vivo/in vitro methodology. Five pigs (23 (sd 1·6) kg body weight) were fed a human-type diet. On day 15, pigs were euthanised. Digesta from terminal jejunum and terminal ileum were collected as substrates for fermentation. Ileal and caecal digesta were collected for preparing microbial inocula. Terminal jejunal digesta were fermented in vitro with a pooled ileal digesta inoculum for 2 h, whereas terminal ileal digesta were fermented in vitro with a pooled caecal digesta inoculum for 24 h. The ileal organic matter fermentability (28 %) was not different from hindgut fermentation (35 %). However, the organic matter fermented was 66 % greater for ileal fermentation than hindgut fermentation (P = 0·04). Total numbers of bacteria in ileal and caecal digesta did not differ (P = 0·09). Differences (P < 0·05) were observed in the taxonomic composition. For instance, ileal digesta contained 32-fold greater number of the genus Enterococcus, whereas caecal digesta had a 227-fold greater number of the genus Ruminococcus. Acetate synthesis and iso-valerate synthesis were greater (P < 0·05) for ileal fermentation than hindgut fermentation, but propionate, butyrate and valerate synthesis was lower. SCFA were absorbed in the gastrointestinal tract location where they were synthesised. In conclusion, a quantitatively important degree of fermentation occurs in the ileum of the growing pig fed a human-type diet.


1977 ◽  
Vol 86 (1) ◽  
pp. 216-224 ◽  
Author(s):  
J. Geelen ◽  
A. Coert ◽  
R. Meijer ◽  
J. van der Vies

ABSTRACT The metabolism of testosterone undecanoate (TU) and testosterone (T) is studied in the gastrointestinal wall of the rat in vitro. A comparison is made with the in vivo metabolism of these compounds in the rat. The major metabolite first appearing during incubation of TU with the small intestine is T. Incubation of TU or T with the small intestine reveals a great similarity between the metabolite patterns obtained. This is also the case with the patterns derived from portal vein plasma upon oral administration of TU and T. Incubation of different parts of the gastrointestinal tract with TU or T shows that the greatest metabolic activity is located in the wall of the small intestine. Unlike T, TU is metabolized only to a small extent in the wall of the stomach and the large intestine.


2019 ◽  
Vol 121 (10) ◽  
pp. 1124-1136 ◽  
Author(s):  
Bianca M. J. Martens ◽  
Thomas Flécher ◽  
Sonja de Vries ◽  
Henk A. Schols ◽  
Erik M. A. M. Bruininx ◽  
...  

AbstractThis study aimed to examine in vivo starch digestion kinetics and to unravel the mechanisms of starch hydrolysing enzymes. Ninety pigs (23 (sd 2·1) kg body weight) were assigned to one of nine treatments in a 3×3 factorial arrangement, with starch source (barley, maize, high-amylose (HA) maize) and form (isolated, within cereal matrix, extruded) as factors. We determined starch digestion coefficients (DC), starch breakdown products and digesta retention times in four small-intestinal segments (SI1–4). Starch digestion in SI2 of pigs fed barley and maize, exceeded starch digestion of pigs fed HA maize by 0·20–0·33 DC units (P<0·01). In SI3–4, barley starch were completely digested, whereas the cereal matrix of maize hampered digestion and generated 16 % resistant starch in the small intestine (P<0·001). Extrusion increased the DC of maize and HA maize starch throughout the small intestine but not that of barley (P<0·05). Up to 25 % of starch residuals in the proximal small intestine of pigs was present as glucose and soluble α(1–4) maltodextrins. The high abundance of glucose, maltose and maltotriose in the proximal small intestine indicates activity of brush-border enzymes in the intestinal lumen, which is exceeded by α-amylase activity. Furthermore, we found that in vivo starch digestion exceeded our in vitro predictions for rapidly digested starch, which indicates that the role of the stomach on starch digestion is currently underestimated. Consequently, in vivo glucose release of slowly digestible starch is less gradual than expected, which challenges the prediction quality of the in vitro assay.


2016 ◽  
Author(s):  
NR Barash ◽  
C Nosala ◽  
JK Pham ◽  
SG Mclnally ◽  
S Gourguechon ◽  
...  

AbstractGiardiais a highly prevalent, yet understudied protistan parasite causing diarrheal disease worldwide. Hosts ingestGiardiacysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host is largely inferred from laboratory culture and thus may not mirrorGiardiaphysiology in the host. Here we have developed bioluminescent imaging (BLI) to directly interrogate and quantify thein vivotemporospatial dynamics of giardiasis, thereby providing an improved murine model to evaluate anti-Giardiadrugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine non-uniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the entire duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high-density laboratory cultures of parasites are also stimulated to encyst. This work overturns the assumption that parasites encyst later during infection as they are dislodged and travel through the colon. We suggest that these high-density regions of parasite colonization likely result in localized pathology to the epithelium, and encystation occurs when trophozoites reach a threshold density due to local nutrient depletion. This more accurate visualization of giardiasis redefines the dynamics ofin vivo Giardialife cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host.SignificanceGiardiais a single-celled parasite causing both acute and chronic diarrheal disease in over one billion people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics ofGiardiainfections in the host has remained limited, and largely inferred from laboratory culture. To better understand giardiasis in the host, we developed imaging methods to quantifyGiardiaexpressing bioluminescent physiological reporters in live mice. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. Furthermore, this work provides evidence of a parasite density-based threshold for the differentiation ofGiardiainto cysts in the host. These findings overturn existing paradigms of giardiasis infection dynamics in the host.


mSphere ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
N. R. Barash ◽  
C. Nosala ◽  
J. K. Pham ◽  
S. G. McInally ◽  
S. Gourguechon ◽  
...  

ABSTRACT Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation. Giardia lamblia is a highly prevalent yet understudied protistan parasite causing significant diarrheal disease worldwide. Hosts ingest Giardia cysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host are largely inferred from laboratory culture and thus may not mirror Giardia physiology in the host. Here, we have developed bioluminescent imaging (BLI) to directly interrogate and quantify the in vivo temporospatial dynamics of Giardia infection, thereby providing an improved murine model to evaluate anti-Giardia drugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine nonuniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high density contributes to the initiation of encystation in laboratory culture. We suggest that these high-density in vivo foci of colonizing and encysting Giardia likely result in localized disruption to the epithelium. This more accurate visualization of giardiasis redefines the dynamics of the in vivo Giardia life cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host. IMPORTANCE Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation.


2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Carlos Montoya ◽  
Edward de Haas ◽  
Paul Blatchford ◽  
Paul Moughan

Abstract Objectives This study aimed to compare ileal and hindgut fermentations in the pig model using a combined in vivo/in vitro methodology. Methods Pigs (23 kg bodyweight, n = 5) were fed a human-type diet for 15 days. On day 15, pigs were euthanased and the small intestine was immediately dissected out and ligated in three equal lengths. Digesta from the last 50 cm of the second (terminal jejunum) and last (terminal ileum) third sections of the small intestine were collected as substrates. Digesta from the remaining last third (i.e., last third minus 50 cm) of the small intestine (ileum) was collected along with caecal digesta for preparing inocula. Terminal jejunal digesta substrates were fermented in vitro with a pooled ileal digesta inoculum for 2 h (ileal fermentation), while terminal ileal digesta substrates were fermented in vitro with a pooled caecal digesta inoculum for 24 h (hindgut fermentation). Results The ileal organic matter (OM) fermentability (28%) was similar than the hindgut counterpart (35%) (P > 0.05). However, the fermentable OM was 63% higher during ileal fermentation than hindgut fermentation (P < 0.05). The production of acetic, isovaleric and succinic acids was higher during ileal fermentation than caecal fermentation (P < 0.05), but the production of propionic, iso-butyric, butyric, valeric and pyruvic acids was lower (P < 0.05). The SCFAs produced in each gastrointestinal tract location was absorbed in their respective gastrointestinal tract location. Conclusions An important amount of OM is fermented in the ileum producing comparable amounts of short-chain fatty acids and organic acids to hindgut fermentation. This challenge the current paradigm concerning gastrointestinal tract fermentation. Funding Sources Centre of Research Excellence Fund from the Tertiary Education.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Moe Ichikawa ◽  
Hiroki Akamine ◽  
Michika Murata ◽  
Sumito Ito ◽  
Kazuo Takayama ◽  
...  

AbstractCaco-2 cells are widely used as an in vitro intestinal epithelial cell model because they can form a monolayer and predict drug absorption with high accuracy. However, Caco-2 cells hardly express cytochrome P450 (CYP), a drug-metabolizing enzyme. It is known that CYP3A4 is the dominant drug-metabolizing enzyme in human small intestine. In this study, we generated CYP3A4-expressing Caco-2 (CYP3A4-Caco-2) cells and attempted to establish a model that can simultaneously evaluate drug absorption and metabolism. CYP3A4-Caco-2 cells were generated by piggyBac transposon vectors. A tetracycline-controllable CYP3A4 expression cassette (tet-on system) was stably transduced into Caco-2 cells, thus regulating the levels of CYP3A4 expression depending on the doxycycline concentration. The CYP3A4 expression levels in CYP3A4-Caco-2 cells cultured in the presence of doxycycline were similar to or higher than those of adult small intestine. The CYP3A4-Caco-2 cells had enough ability to metabolize midazolam, a substrate of CYP3A4. CYP3A4 overexpression had no negative effects on cell proliferation, barrier function, and P-glycoprotein activity in Caco-2 cells. Thus, we succeeded in establishing Caco-2 cells with CYP3A4 metabolizing activity comparable to in vivo human intestinal tissue. This cell line would be useful in pharmaceutical studies as a model that can simultaneously evaluate drug absorption and metabolism.


2019 ◽  
Vol 25 (37) ◽  
pp. 4946-4967 ◽  
Author(s):  
Anna K. Kiss ◽  
Jakub P. Piwowarski

The popularity of food products and medicinal plant materials containing hydrolysable tannins (HT) is nowadays rapidly increasing. Among various health effects attributable to the products of plant origin rich in gallotannins and/or ellagitannins the most often underlined is the beneficial influence on diseases possessing inflammatory background. Results of clinical, interventional and animal in vivo studies clearly indicate the antiinflammatory potential of HT-containing products, as well as pure ellagitannins and gallotannins. In recent years a great emphasis has been put on the consideration of metabolism and bioavailability of natural products during examination of their biological effects. Conducted in vivo and in vitro studies of polyphenols metabolism put a new light on this issue and indicate the gut microbiota to play a crucial role in the health effects following their oral administration. The aim of the review is to summarize the knowledge about HT-containing products’ phytochemistry and their anti-inflammatory effects together with discussion of the data about observed biological activities with regards to the current concepts on the HTs’ bioavailability and metabolism. Orally administered HT-containing products due to the limited bioavailability of ellagitannins and gallotannins can influence immune response at the level of gastrointestinal tract as well as express modulating effects on the gut microbiota composition. However, due to the chemical changes being a result of their transit through gastrointestinal tract, comprising of hydrolysis and gut microbiota metabolism, the activity of produced metabolites has to be taken into consideration. Studies regarding biological effects of the HTs’ metabolites, in particular urolithins, indicate their strong and structure-dependent anti-inflammatory activities, being observed at the concentrations, which fit the range of their established bioavailability. The impact of HTs on inflammatory processes has been well established on various in vivo and in vitro models, while influence of microbiota metabolites on silencing the immune response gives a new perspective on understanding anti-inflammatory effects attributed to HT containing products, especially their postulated effectiveness in inflammatory bowel diseases (IBD) and cardiovascular diseases.


1979 ◽  
Vol 41 (1) ◽  
pp. 47-51 ◽  
Author(s):  
D. F. Evered ◽  
F. Sadoogh-Abasian

1. The disaccharide lactulose (galactosyl-β-1,4-fructose) was poorly absorbed from rat small intestine in vitro and human mouth in vivo.2. These results confirm indirect clinical evidence of poor absorption from the intestine.3. The presence of calcium ions, or absence of sodium ions, had no effect on lactulose absorption from the buccal cavity.4. The presence of ouabain, or absence of Na+, did not decrease the absorption of lactulose from small intestine.5. It is thought that the mode of transport, in both instances, is by passive diffusion with the concentration gradient.


Sign in / Sign up

Export Citation Format

Share Document