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PubMedDate not supplied

Effects of prefeeding a prebiotic on diarrhea and colonic cell proliferation in piglets fed lactulose.

OBJECTIVES: Severe lactulose malabsorption causes osmotic diarrhea and decreased cecal cell proliferation. We tested the hypothesis that prefeeding with inulin, a prebiotic, would attenuate these effects. METHODS: Piglets aged 10 days were randomized to 3 feeding groups (n = 6 each group): Control (CON), fed sow-milk replacement formula (SMR; lactose, 60 g/L) for 14 days; a lactulose-challenged group (LAC) that was fed SMR for 7 days and then a formula containing lactose (30 g/L) and lactulose (60 g/L) for 7 days; and a group prefed SMR containing inulin (3 g/L) for 7 days and then fed the lactulose-supplemented formula (INULIN). Groups CON and INULIN were pair-fed to LAC. Then, cecal tissue was collected for histology, determination of crypt cell proliferation index, apoptosis, and Western blot determination of expression of Bax, a pro-apoptotic protein. RESULTS: The fraction of days when diarrhea was present (mean +/- SD) was greater for LAC (0.87 +/- 0.14; p = .004) than CON (0.28 +/- 0.22; INULIN: 0.52 +/- 0.44; p = .058 vs LAC). Cell proliferation index for the total crypt was less for LAC (0.12 +/- 0.04; p = .016) compared with CON (0.20 +/- 0.04; INULIN: 0.15 +/- 0.04; p = .06 vs LAC). BAX protein expression and apoptosis were similar in the 3 groups. CONCLUSIONS: We observed trends consistent with the hypothesis that prefeeding inulin attenuates diarrhea and the reduction in cell proliferation caused by lactulose.

Animals↗
PubMed1979

Validity of endogenous creatinine clearance in low birthweight infants.

Despite methodologic problems, endogenous creatinine clearance is commonly used as an estimation of glomerular filtration rate (GFR). Inulin clearance was compared to endogenous creatinine clearance in a group of low birthweight infants to establish the validity of the latter. Thirty-three low birthweight infants (birthweight mean = 1600 g, gestational age mean = 33 wk) were studied between 10 hr and 10 days of age to simultaneously measure GFR by inulin and endogenous creatinine clearances. Inulin and creatinine clearances correlated directly (r = 0.738, P greater than 0.001). The slope of the regression line suggested an overestimation of GFR (inulin clearance) by creatinine clearance at the low GFR range and an underestimation at the high GFR range. The data were divided into two groups by the median inulin clearance (12.5 ml/min/1.73m2). The ratio of creatinine to inulin clearance was significantly higher in the low GFR group (1.28 +/- 0.16 vs. 0.89 +/- 0.04 SEM, n = 19, P less than 0.05). There was no difference between the two groups in plasma creatinine, birthweight, gestational age, incidence of respiratory distress, or oxygen requirements at the time of the studies. Endogenous creatinine clearance represents a good estimation of GFR (inulin clearance) in low birthweight infants. However, at the low GFR range, it represents an overestimation and at the high GFR range, an underestimation.

Bilirubin↗
PubMed1992

Contribution of interstitial diffusion in drug absorption from perfused rabbit muscle: effect of hyaluronidase on absorption.

[3H]Water and [14C]inulin were injected into perfused rabbit muscle with or without hyaluronidase (300 units/ml) and their absorption into venous effluent from muscle was determined. Hyaluronidase accelerated the absorption of both compounds but the enhancement of [14C]inulin was much larger than that for [3H]water. The pharmacokinetic analysis of venous appearance curves based on a physiological diffusion model elucidated that interstitial diffusion of [14C]inulin was remarkably increased by hyaluronidase treatment, suggesting the existence of steric hindrance for it by the polysaccharide network under normal conditions. Enhancement of [3H]water diffusion was also detected although enhancement ratio was about one-half of that of [14C]inulin. Mean time necessary for each process was calculated using the statistical moment concepts. The results suggested predominant contribution of the interstitial diffusion process and secondary and little contribution of local perfusion flow and permeation process across the capillary wall, respectively, in total absorption of [14C]inulin. Effect of hyaluronidase on transcapillary movement of [14C]inulin was studied using an in vitro diffusion experiment with cultured endothelial cell monolayer and no enhancing effect was shown on [14C]inulin transport across the cell monolayer. The contribution of the local perfusion flow, on the other hand, was shown to be almost equivalent to that of the diffusion process in the total absorption of [3H]water.

Absorption↗
PubMed1988

[Pharmacokinetic study on oxalate in rats].

The pharmacokinetics of oxalate were studied in normal and nephrectomized rats, using radioisotope-labelled oxalate to resolve the mechanism of calcium oxalate stone formation. Plasma disappearance of 14C-oxalate was analyzed with a 2-compartment open model, and each compartment volume, the first-order rate constant for elimination, and the first-order rate constant for transfer between the central compartment and peripheral compartment were obtained. These values were compared with those for inulin. In normal rats, the total distribution volume was 57% of body weight for oxalate and 34% for inulin. The elimination rate constant from the central compartment for oxalate was lower than that for inulin, but oxalate had a much larger central compartment volume than inulin. Thus, the total clearance of oxalate was greater than that of inulin. In nephrectomized rats, total clearance of oxalate decreased to 1/6 of that in normal rats, while total clearance of inulin decreased to 1/27 of that in normal rats. These results suggest that oxalate is more diffusible than inulin, and that oxalate is excreted mainly from the kidney.

Animals↗
PubMed1981

Internal K+ and Na+ concentrations and the volume of hypothalamic synaptosomes.

Hypothalamic synaptosomes, prepared by discontinuous sucrose density gradient centrifugation, were suspended in media of varying osmolarity and ionic composition and the internal concentrations of K+ and Na+ were measured. The intrasynaptosomal volume was determined using [14C]inulin, 35SO4 or [14C]sucrose as extracellular markers. When the synaptosomes were suspended in 0.32 M sucrose the distribution volume of [14C]inulin and 35SO4 were similar. However, when the medium contained 140 mM NaCl and 5 mM KCl the 35SO4 space was equal to the total water space while the distribution volume of [14C]inulin corresponded to 35-51% of the total water space. [14C]sucrose distributed in a larger volume than did [14C]inulin, presumably due to intracellular permeation of sucrose. Using inulin as an extracellular marker the synaptosome volume was found to be inversely proportionate to the tonicity of the medium. [14C]inulin was considered a suitable marker of the extrasynaptosomal space and was used when determining intrasynaptosomal K+ and Na+ concentrations. The internal concentration of K+ was considerably higher than the external indicating that the synaptosomes were able to retain K+ against a concentration gradient. The synaptosomes gained Na+ when transferred to media containing 140 mM NaCl. The internal concentrations of K+ and Na+ were unaffected by glucose and elevated temperature and was only moderately changed during 90 min of incubation. The equilibrium potentials for K+ and Na+ were -68 and 13 mV respectively when the medium consisted of 0.03 M sucrose containing 140 mM NaCl, 5 mM KCl. It is concluded that hypothalamic synaptosomes can maintain a high transmembrane concentration gradient for K+ whereas the membrane is rather easily penetrated by Na+.

Animals↗
PubMed1985

Receptor-mediated uptake of horseradish peroxidase in innervated and denervated skeletal muscle.

The in vitro uptake of [3H]inulin and horseradish peroxidase (HRP) has been studied in innervated and 6 days denervated extensor digitorum longus muscle of the mouse. Both markers were taken up at a higher rate in denervated muscle. The increase in uptake after denervation was, however, larger for HRP than for [3H]inulin. After 2 h incubation at 37 degrees C, pH 7.3, in the presence of equimolar concentrations of HRP and [3H]inulin (approx. 2.1 microM), the uptake of HRP was approx. 8 times as great as the uptake of [3H]inulin in the same innervated muscles. In denervated muscle the HRP uptake was approx. 19 times as great as the [3H]inulin uptake in the same muscles. Various possible explanations of these differences in uptake have been considered and tested experimentally. [3H]Inulin uptake in skeletal muscle has previously been shown to obey bulk kinetics. The present investigation shows the HRP uptake to obey saturation kinetics. The HRP uptake shows dependency on divalent cations and is reduced if incubation is carried out at pH 6.4. The uptake of HRP, when used at a low, non-saturating concentration (10 micrograms/ml approx. 0.25 microM), is inhibited greater than or equal to 60% by yeast mannan (0.1 mg/ml), ribonuclease B (0.1 mg/ml, approx. 7.4 microM), mannose (30 mM), monodansylcadaverine (1 mM), chloroquine (100 microM), trifluoperazine (25 microM) or maleic acid (2 mM). It is concluded that HRP is taken up in innervated and denervated skeletal muscle by a process of receptor-mediated endocytosis and that this uptake is under neurotrophic control.

Animals↗
PubMed1985

Intracellular digestion of saturated and unsaturated phospholipid liposomes by mucosal cells. Possible mechanism of transport of liposomally entrapped macromolecules across the isolated vascularly perfused rabbit ileum.

The mechanism of intestinal absorption of liposomally entrapped [14C]inulin and 125I-labelled poly(vinylpyrrolidone) was studied using the isolated rabbit intestinal loop with intact perfused vasculature, a system more closely resembling an in vivo system than the everted sac technique. [14C]Inulin or 125I-poly(vinylpyrrolidone) was entrapped in liposomes prepared from unsaturated egg phosphatidylcholine and soya phosphatidylcholine, and saturated distearoylphosphatidylcholine (18:0), dipalmitoylphosphatidylcholine (16:0) and dimyrostoylphosphatidylcholine (14:0). Free and liposomally entrapped macromolecules were introduced in the ileum and the transport of liposomes and entrapped macromolecules into the venous effluent was monitored by measuring the presence of the aqueous marker 125I-poly(vinylpyrrolidone) or [14C]inulin, and lipid marker [3H]cholesterol. The results show that intact liposomes are not transported across intestine into the venous effluent, but they are taken up by mucosal cells and digested intracellularly, releasing the entrapped markers 125I-poly(vinylpyrrolidone) and [14C]inulin. These markers are then transported into the venous effluent as free molecules. The absorption of liposomally entrapped [14C]inulin into the venous effluent is biphasic, first slow for 30 min (i.e., a lag period of 30 min), followed by a rapid linear increase. The duration of the lag period and the rate of absorption of the entrapped [14C]inulin are dependent on the degree of saturation and the transition temperature of the phospholipids used to prepare liposomes. The possible explanation of the lag period based on the evidence presented here is that it is the time required for the liposomes to be taken up by mucosal cells and digested intracellularly. Intracellular digestion of liposomes prepared from saturated phospholipids is more rapid than from those prepared from unsaturated phospholipids, and the greater the fatty acid chain length of the saturated phospholipids the more rapid the intracellular degradation of liposomes.

Animals↗
PubMed2006

The choice of a suitable oligosaccharide to prevent aggregation of PEGylated nanoparticles during freeze thawing and freeze drying.

In a previous study we have shown that the oligosaccharide inulin can prevent aggregation of poly(ethylene glycol) (PEG) coated plasmid DNA/cationic liposome complexes ("PEGylated lipoplexes") during freeze thawing and freeze drying [Hinrichs et al., 2005. J. Control. Release 103, 465]. By contrast, dextran clearly failed as stabilizer. These results were ascribed to the fact that inulin and PEG are compatible while dextran and PEG are not. In this study the stabilizing capacities of inulin and dextran (of various molecular weights) during freeze thawing and freeze drying of four different types of nanoparticles, each type with different amounts of PEG at their surface, were investigated. Freeze drying and freeze thawing of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/dioleoyl-phosphatidyl-ethanolamine (DOPE) liposomes and egg phosphatidyl choline (EPC)/cholesterol (CHOL) liposomes showed that inulins are excellent stabilizers even for highly PEGylated liposomes while (especially higher molecular weight) dextrans dramatically lost their stabilizing capacity when increasing the degree of PEGylation of the liposomes. The same results were obtained for plasmid DNA/DOTAP/DOPE complexes. Finally, both inulin and dextran could prevent full aggregation of plasmid DNA/polyethylenimine (PEI) complexes independent whether PEI was PEGylated or not. It is concluded that inulins are preferred as stabilizers over dextrans for various types of PEGylated nanoparticles due to their compatibility with PEG.

Cholesterol↗
PubMed2001

Tryptophan glycoconjugate as a novel marker of renal function.

PURPOSE: Neither serum creatinine concentration nor creatinine clearance assess renal function accurately. Serum creatinine concentration is affected by muscle mass, and the creatinine clearance overestimates the glomerular filtration rate because of tubular secretion of creatinine. The present study was designed to determine whether serum concentrations of 2-(alpha-mannopyranosyl)-L-tryptophan (MPT), a tryptophan glycoconjugate, can be used as a marker of renal function. METHODS: Clearances of MPT and of inulin were compared in normal rats and in rats with cisplatin-induced acute renal failure. We also compared the clearances of MPT and of creatinine with inulin clearance in 25 patients with chronic renal disease. Serum concentrations of MPT and creatinine as a function of MPT clearance were determined in 108 patients with chronic renal disease. RESULTS: There was strong linear correlation between clearances of MPT and inulin in rats (r = 0.97) and humans (r = 0.87), indicating that renal handling of MPT is similar to that of inulin. In humans, linear regression analyses indicated that MPT was a better indicator of inulin clearance than was creatinine clearance. At the same level of renal function, serum creatinine concentrations tended to be lower in patients with less muscle mass (as indicated by a urinary creatinine excretion <1,000 mg in 24 hours) than in those who excreted >1,000 mg in 24 hours, whereas serum MPT concentrations were not affected by creatinine excretion. CONCLUSION: MPT clearance can replace inulin clearance in the clinical setting. The serum MPT concentration is an accurate measure of renal function even in patients with diminished muscle mass, and thus is a better indicator of renal function than is the serum creatinine concentration.

Acute Kidney Injury↗
PubMed1997

Evidence for pore-like opening of the blood-brain barrier following forebrain ischemia in rats.

The nature of the delayed blood-brain barrier (BBB) opening that occurs in rats subjected to forebrain ischemia by the technique of two-vessel (carotid) occlusion plus hypovolemic hypotension (2VO ischemia) was probed by examining the simultaneous, trans-barrier movement of two hydrophilic, normally poorly permeative solutes of markedly different molecular size: sucrose (MW = 342) and inulin (MW approximately 5000). Pentobarbital-anesthetized, male, Sprague-Dawley rats (342-374 g) were subjected to 10 min of 2VO ischemia (tympanic temperature, 37.5-38.0 degrees C); 6 h later they were reanesthetized and, along with non-ischemic controls, injected i.v. with [14C]sucrose and [3H]inulin. Transfer constants (Kis) for blood-to-brain movement of the tracers and Vis (apparent initial volumes of tracer distribution) were determined for six brain regions by the multiple-time, graphical method (tracer circulation times from 3 to 30 min). Vis differed little or insignificantly between the two tracers, or between control and post-ischemic rats; the values did not suggest appreciable endothelial binding of either tracer that might lead to its uptake by adsorptive-phase endocytosis. In the controls, regional Kis +/- S.E.M. (nl g(-1) s(-1)) for inulin ranged from 0.18 +/- 0.04 to 0.31 +/- 0.09 and were significantly lower (P < 0.01) than Kis for sucrose (1.53 +/- 0.16-1.91 +/- 0.29). The Ki ratio (sucrose/inulin) across brain regions (mean, 6.6; S.E.M., 0.6) was much lower than would be expected according to the concept that movement of most organic non-electrolytes across the intact BBB occurs by dissolution in and diffusion through endothelial cell plasma membranes, at a rate proportional to the lipid solubility and diffusivity of the solute. This finding is interpreted as indicating that a portion of the transfer of sucrose and inulin occurred by a mechanism other than dissolution-diffusion (e.g., via pores or vesicles). In the post-ischemic rats, Kis for both tracers were elevated significantly (P < 0.01) in parietal cortex, striatum, hippocampus, and midbrain. The post-ischemic increases (delta Kis) in these regions were greater for sucrose (1.90-3.31 nl g(-1) s(-1)) than for inulin (0.80-1.33). Across brain regions the ratio between sucrose delta Ki and inulin delta Ki averaged 2.9 (S.E.M., 0.2), a value significantly greater than the ratio of 1 that would be expected were the BBB opening due to an enhancement of micropinocytosis and vesicular transport. The correspondence of the mean delta Ki ratio with the ratio of the free diffusion coefficients of the tracers (D(f, suc)/D(f, inu) = 2.9; water, 38 degrees C) suggests that the delayed opening of the BBB following 2VO ischemia involves the formation of trans- or paracellular, aqueous pores or channels.

Animals↗
PubMed2003

Hollow filler-binders as excipients for direct compaction.

PURPOSE: As an effect of their plastic deformation behavior, ductile materials create a large surface for bonding during compaction. However, a serious drawback is their high lubricant sensitivity, preventing the formation of strong bonds. The purpose of this study was both an increase in compactibility and a reduction of the lubricant sensitivity of ductile filler-binders by using hollow particles. This was illustrated for inulin. METHODS: Both solid and hollow inulin particles were prepared by spray-drying. Unlubricated tablets and tablets containing 0.5% magnesium stearate were compressed in a compaction simulator, operating at 300 mm/s. The tablet crushing strength was determined with a Schleuniger apparatus. RESULTS: The compaction of unlubricated, solid inulin particles showed that the product had good compatibility. This was caused by plastic deformation of the ductile, amorphous material under load, creating a large surface for bonding. After lubrication, however, the bonding properties decreased significantly, which was caused by the presence of a lubricant film. Hollow inulin particles have an increased compactibility as compared with solid particles and a strongly reduced lubricant sensitivity. Scanning electron micrographs show that hollow particles fragment before they start plastic deformation. This fragmentation behavior is supported by tablet surface area measurements and calculation of the buckling strength. This effect was responsible for both a higher crushing strength and a lower lubricant sensitivity as compared with solid inulin particles. CONCLUSIONS: Compactibility of inulin particles can be increased, and lubricant sensitivity can be decreased by using hollow instead of solid particles.

Drug Compounding↗
PubMed1980

Pathophysiology of hemodynamically mediated acute renal failure in man.

A tubular injury characterized by intraluminal obstruction and transtubular backleak of glomerular filtrate occurs in experimental acute renal failure (ARF) in animals. To determine whether these alterations also occur in human ARF, we studied 44 patients developing nonoliguric ARF following cardiac surgery. The delay in appearance of i.v. administered inulin in urine (Tu) was used as a measure of tubular fluid flow rate. Tu was not longer in 13 ARF patients than it was in control subjects (7.2 vs 9.0 min), suggesting that at least a subpopulation of tubules was widely patent. The fractional urinary dextran clearance profile (thetaD; radii, 20 to 40 A) was then determined in 20 patients with sustained ARF in whom inulin clearance averaged 11 +/- 1 ml/min/1.73 m2. A mass conservation model, which assumes that thetaD in Bowman's space in ARF is the same as that measured in controls, when applied to the experimental observations revealed that, on the average, 42% of filtered inulin was lost by transtubular backleak. A similar fractional inulin backleak (38%) persisted in 11 additional patients in whom ARF had begun to recover and in whom inulin clearance averaged 26 +/- 3 ml/min/1.73 m2. These findings suggest that in hemodynamically-mediated and nonoliguric ARF, (1) tubular obstruction is not homogeneous, and (2) backleak of glomerular filtrate contributes to but does not fully account for depression of inulin clearance.

Acute Kidney Injury↗
PubMed2001

Variability of glomerular filtration rate estimation using single injection methods in Type 1 diabetic patients.

AIM: Single-injection inulin clearance (SIIC) methods without urine collection have often been compared with classical constant-infusion inulin clearance methods. Therefore, we used repeated SIIC measurements to prove the hypothesis of a possible overestimation or variability of inulin clearance in Type 1 diabetic patients. METHODS: Two SIIC periods, glomerular filtration rate 1 and 2 (GFR 1, GFR 2) were performed consecutively on the same day. In diabetic patients, GFR 3 was measured several days later at the same time of day as the GFR 1 had been done. The calculation used a two-compartment modelling system (TCM) which showed excellent agreement to ratio of dose over area under the curve (D/AUC) calculation. RESULTS: Twelve normotensive Type 1 diabetic patients (mean and SD), age 39 (10.7) years, diabetes duration 20 (10.7) years, HbA1c 8.5% (0.82%), albuminuria 13.8 (15.7) mg/24 h and six controls, age 26 (2.6) years were examined. Healthy controls showed an excellent repeatability between GFR 1 111.8 (11.44) and GFR 2 110.8 (11.41) ml.min-1.1.73 m2-1. However, in diabetic patients there was a highly significant decrease between GFR 1 129.4 (11.86) and GFR 2 118.1 (13.05) ml.min-1.1.73 m2-1. GFR 1 with 129.4 (11.86) ml.min-1.1.73 m2-1 did not differ significantly from GFR 3 with 129.9 (12.40) ml.min-1.1.73 m2-1 in diabetic patients (P < 0.839). CONCLUSIONS: In contrast to normal subjects, in Type 1 diabetic patients single-injection inulin clearance technique showed a clinically relevant decrease in GFR on two repeated measurements on the same day. Overestimation of GFR by the first inulin clearance may be caused by incomplete inulin distribution in the slow compartment. Diabet. Med. 18, 464-468 (2001)

Adult↗
PubMed2000

A new procedure for evaluation of renal function without urine collection in rat.

BACKGROUND: A new procedure to improve the accuracy of inulin assessment and renal glomerular filtration rate (GFR) avoiding urine sampling was compared and validated versus the reference procedure (with urine sampling and Anthrone reaction) in conscious unrestrained male Wistar rats. METHODS: The hemodynamic study consisted of a priming dose of inulin (16 mg/kg) and para-aminohippurate (PAH; 8 mg/kg) followed by an infusion of inulin (36 mg/mL) and PAH (5.8 mg/mL) at a rate of 0.055 mL/min until steady-state conditions were reached (105 min). Inulin concentrations from samples were determined by a new enzymatic assay and Anthrone reaction. PAH concentrations were determined according to the standard method described by Smith et al. RESULTS: A high correlation was found between GFR and renal blood flow (RBF) values calculated using the alternative (without urine sampling) and the reference (with urine sampling) clearance techniques (r = 0.98, P < 0.001, and r = 0.97, P < 0.001, respectively). Moreover, a significant and positive correlation between the values obtained from enzymatic and Anthrone inulin assessments was found (r = 0.99, P < 0.001). Likewise, the values of the 95% confidence interval (mean +/- 2 SD) for the enzymatic inulin assay showed a good agreement with those achieved with Anthrone (1.14 +/- 0.21 and 1.14 +/- 0.19 mL. min-1. 100 g-1 rat body weight, respectively). CONCLUSIONS: This new approach has methodological and experimental advantages with respect to traditional procedures, making it a useful tool, not only for research purposes but also in the clinical setting.

Animals↗
PubMed2005

Modulation of gut mucosal biofilms.

Non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. Bifidobacteria and lactobacilli are the most frequently targeted organisms. Less information exists on effects of inulin-type fructans on the composition, metabolism and health-related significance of bacteria at or near the mucosa surface or in the mucus layer forming mucosa-associated biofilms. Using rats inoculated with a human faecal flora as an experimental model we have found that inulin-type fructans in the diet modulated the gut microbiota by stimulation of mucosa-associated bifidobacteria as well as by partial reduction of pathogenic Salmonella enterica subsp. enterica serovar Typhimurium and thereby benefit health. In addition to changes in mucosal biofilms, inulin-type fructans also induced changes in the colonic mucosa stimulating proliferation in the crypts, increasing the release of mucins, and altering the profile of mucin components in the goblet cells and epithelial mucus layer. These results indicate that inulin-type fructans may stabilise the gut mucosal barrier. Dietary supplementation with these prebiotics could offer a new approach to supporting the barrier function of the mucosa.

Animals↗
PubMed1999

In vivo measurement of solute transport rates in a bioartificial organ.

A radioactive tracer technique was used to evaluate the in vivo mass transfer properties of a tissue engineered bioartificial organ. To obtain these measurements, bioartificial organs were first implanted in ten rats and allowed to vascularize for 4 weeks. After vascularization, radioactive inulin was placed within the cell chamber of the device. Following the addition of tracer, blood samples were taken over a 4-h time period and inulin levels were determined. The results of these experiments were interpreted using a compartmental model that describes the transport of inulin from the cell chamber, across the immunoisolation membrane, and into the neovascularized region contained within the adjacent scaffold material. Nonlinear regression analysis of the plasma inulin levels using a four-compartment pharmacokinetic model provided estimates of the membrane permeability, the product of the capillary wall surface area and capillary permeability, and the glomerular filtration rate (GFR). The permeability of the membrane was found to be 3.50 x 10(-5) +/- 1.15 x 10(-5) cm/sec (95% confidence interval, n = 10), which compares favorably to previous in vitro permeability data for this membrane. The capillary wall permeability was found to be 0. 0087 6 0.0029 cm(3)/sec/100 g of tissue. This compares well to a reported value for inulin of 0.01 cm(3)/sec/100 g of tissue. The GFR was found to be 0.44 +/- 0.07 ml/h/g BW, which compares well with a reported value of 0.40 ml/hr/g BW. The inulin tracer technique reported here is a useful tool for assessing the in vivo transport characteristics of a bioartificial organ as well as the vascularization within tissue engineered structures.

Animals↗
PubMed1996

The water-soluble extract of chicory reduces glucose uptake from the perfused jejunum in rats.

Among the components of dietary fiber, the soluble fibers have been found to impair glucose absorption. Little is known, however, about the mechanism of this effect. The direct action of soluble fibers (chicory water-soluble extract and inulin) on the intestinal absorption of glucose was investigated in gutperfused rats. After equilibrium, both jejunal and ileal segments were simultaneously perfused with an isotonic electrolyte solution (pH 7.4) containing glucose (10 mmol/L) and chicory water-soluble extract (chicory extract) or inulin (10 g/L). Each test or control solution was perfused in random sequence, with perfusion times of 30 min. Chicory extract or inulin in the perfusate (10 g/L) inhibited the absorption of glucose from jejunum (P < 0.05). The observed changes in glucose and water absorption caused by chicory extract or inulin were reversible after switching to a fiberfree perfusate. Additionally, net water absorption changed to secretion upon addition of chicory extract or inulin. These results suggest that the reduction in intestinal absorption of glucose observed after perfusion of chicory extract or inulin may be caused by viscosity-related increases in mucosal unstirred layer thickness.

Animals↗
PubMed2001

Modulation of genotoxic enzyme activities by non-digestible oligosaccharide metabolism in in-vitro human gut bacterial ecosystems.

Supplementation of the human diet with prebiotic substances such as inulin and non-digestible oligosaccharides (NDO), e.g., galacto-oligosaccharides (GOS), has been associated with various health benefits. However, little information is available regarding the spatial location of their metabolism in human gut bacterial ecosystems. Therefore, the present study investigated the metabolism of inulin and GOS with respect to bacterial growth, bifidobacterial stimulatory properties and anti-mutagenicity potential, in a three-stage continuous culture model of the colon which reproduces the physicochemical characteristics of the proximal (V1) and distal (V2, V3) colons. Fermentation of both carbohydrates was rapid, and occurred primarily in V1, as evidenced by acid formation. Inulin metabolism was associated with 10-fold stimulation of lactobacillus populations, together with smaller increases in bifidobacterial cell counts in V1. However, peptostreptococci, enterococci and Clostridium perfringens also increased in this fermentation vessel. In contrast, GOS was only weakly bifidogenic in V1, although these bacteria did proliferate in V2. GOS also increased lactobacilli by an order of magnitude in V1. However, overall changes in microbial populations resulting from inulin or GOS addition were minimal in V2 and V3. Potential beneficial effects of inulin metabolism included minor reductions in beta-glucosidase and beta-glucuronidase, whereas GOS strongly suppressed these enzymes, together with arylsulphatase (AS). Growth of putatively health promoting micro-organisms was not only associated with reductions in enzymes linked to genotoxicity. For example, both carbohydrates stimulated synthesis of nitroreductase and azoreductase, throughout the fermentation system, while inulin increased AS. Colonic transit time is an important factor in bacterial metabolism in the large bowel, and these data suggest that, in some circumstances, NDO fermentation will occurprincipally in the proximal colon.

Adult↗