Here, we expand upon these studies and demonstrate that EP-3533 can accurately stage biliary fibrosis in bileduct ligated (BDL) rats. While our initial studies were performed on high field small animal scanners, we now show efficacy using a 1.5-tesla clinical MRI scanner in order to further clinical translation. In addition, our previous studies quantified changes in the contrast-to-noise ratio (ΔCNR) between liver and adjacent skeletal muscle after injection of EP-3533 and were typically performed on a just a few liver image slices [11-14]. In the current work we have made fibrosis quantification more extensive by introducing a respiratory-gated three dimensional (3D) inversion recovery imaging sequence that allows us to measure the change in longitudinal relaxation rate (ΔR1) induced by EP-3533 on a pixel-wise basis throughout the entire liver. Since ΔR1 is linearly proportional to the Gadolinium concentration, it has the potential to provide a more quantitative and robust metric than ΔCNR for the assessment of fibrosis, and to measure disease heterogeneity within the liver. In order to test this, we measured fibrosis in rapamycin treated BDL rats where considerable variability was observed previously in liver fibrosis response to rapamycin [16, 17]. The rapamycin experiments therefore provided a rigorous test of the ability of EP-3533 to detect differences in disease progression and response to therapy.
Muscle mass loss and hepatic encephalopathy (complex neuropsychiatric disorder) are serious complications of chronic liver disease (cirrhosis) which impact negatively on clinical outcome and quality of life and increase mortality. Liver disease leads to hyperammonemia and ammonia toxicity is believed to play a major role in the pathogenesis of hepatic encephalopathy. However, the effects of ammonia are not brain-specific and therefore may also affect other organs and tissues including muscle. The precise pathophysiological mechanisms underlying muscle wasting in chronic liver disease remains to be elucidated. In the present study, we characterized body composition as well as muscle protein synthesis in cirrhotic rats with hepatic encephalopathy using the 6-week bileductligation (BDL) model which recapitulates the main features of cirrhosis. Compared to sham-operated control animals, BDL rats display significant decreased gain in body weight, altered body composition, decreased gastrocnemius muscle mass and circumference as well as altered muscle morphology. Muscle protein synthesis was also significantly reduced in BDL rats compared to control animals. These findings demonstrate that the 6-week BDL experimental rat is a relevant model to study liver disease-induced muscle mass loss.
Fig. 8. Long-term protective impact of GB after BDL. (A) TGR5-KO mice are more sensitive to chronic BDL. Body weight (bw) loss was greater, and survival was only slightly impaired (not statistically different) in TGR5-KO vs. WT mice (left graphs) (n = 9–11 mice/ group). Right histogram: greater bw loss at 15 days after CC in BDL WT but not TGR5-KO mice (n = 4 –5 mice/group). (B) CC exacerbates inﬂammatory inﬁltration and proliferative response 15 days after BDL. Left: Gr1 (macrophage and neutrophil polymorphonuclear cells) immunostaining on liver sections from WT and TGR5-KO mice after BDL or BDL + CC. Right: Ki67 and E- cadherin co-immunostaining on liver sections from WT and TGR5-KO mice after BDL or BDL + CC. Gr1+ cells and Ki67+ hepatocytes: restricted to periportal regions in WT BDL mice; more mediolobular distribution in TGR5-KO as well as in WT and TGR5-KO mice with BDL + CC. Representative images, n = 5 –7 mice. Obj. ×10, scale bar: 100 l m. (C) GB bile volume in WT and TGR5-KO mice after BDL. Left histogram: GB bile volume analysis (n = 4–25 mice/group); representative photographs at 7 days after BDL. Dotted lines: GB area; white arrows: macroscopic bile infarcts observed on the liver surface. * p <0.05; ***p<0.001; Student’s t test. Panel A middle graph: log-rank (Mantel-Cox) test was used to compare the survival curves. BDL, bileductligation; CC, cholecystectomy; GB, gallbladder; KO, knockout; TGR5, Takeda G protein coupled receptor; WT, wild-type.
10.Biolo G, Maggi SP, Williams BD, Tipton KD, Wolfe RR. Increased rates of muscle protein turnover and amino acid transport after resis ‐tance exercise in humans. Am J Physiol Metab. 1995;268:E514‐E520.
11.Bosoi CR, Oliveira MM, Ochoa ‐Sanchez R, et al. The bileduct li‐gated rat: A relevant model to study muscle mass loss in cirrhosis. Metab Brain Dis. 2017;32:513 ‐518.12.Giusto M, Barberi L, Di Sario F, et al. Skeletal muscle myopenia in mice model of bileductligation and carbon tetrachloride ‐induced liver cirrhosis. Physiol Rep. 2017;5:e13153.
The pathogenesis of hepatic encephalopathy is multifactorial, involving gut-derived toxins such as ammonia, which has been demonstrated to induce oxidative stress. Therefore, a primary hepatic encephalopathy treatment target is reducing ammonia production in the gastrointestinal tract. AST-120, an oral adsorbent of engineered activated carbon microspheres with surface areas exceeding 1600 m 2 /g, acts as a sink for neurotoxins and hepatotoxins present in the gut. We evaluated the capacity of AST-120 to adsorb ammonia in vitro and to lower blood ammonia, oxidative stress and brain edema in cirrhotic rats. Cirrhosis was induced in rats by bileductligation for 6 weeks. AST-120 was administered by gavage preventively for 6 weeks (0.1, 1, and 4 g/kg/day). In addition, AST-120 was evaluated as a short-term treatment for 2 weeks and 3 days (1 g/kg/day) and as a sink to adsorb intravenously infused ammonium acetate. In vitro, AST-120 efficiently adsorbed ammonia. Ammonia levels significantly decreased in a dose-dependent manner for all AST-120–treated bileduct-ligated rats (nontreated: 177.3 ± 30.8 μM; AST-120, 0.1 g/kg/day: 121.9 ± 13.8 μM; AST-120, 1 g/kg/day: 80.9 ± 30.0 μM; AST-120, 4 g/kg/day: 48.8 ± 19.6 μM) and significantly correlated with doses of AST-120 (r = −0.6603). Brain water content and locomotor activity normalized after AST-120 treatments, whereas arterial reactive oxygen species levels remained unchanged. Furthermore, AST-120 significantly attenuated a rise in arterial ammonia after ammonium acetate administration (intravenously). Conclusion:AST-120 treatment decreased arterial ammonia levels, normalized brain water content and locomotor activity but did not demonstrate an effect on systemic oxidative stress. Also, AST-120 acts as an ammonia sink, efficiently removing blood-derived ammonia. Additional studies are warranted to evaluate the effects of AST-120 on hepatic encephalopathy in patients with advanced liver disease. (HEPATOLOGY 2011;)
☯ These authors contributed equally to this work. * firstname.lastname@example.org
Bile acids have recently been demonstrated as molecules with endocrine activities control- ling several physiological functions such as immunity and glucose homeostases. They act mainly through two receptors, the nuclear receptor Farnesol-X-Receptor alpha (FXR α) and the G-protein coupled receptor (TGR5). These recent studies have led to the idea that mole- cules derived from bile acids (BAs) and targeting their receptors must be good targets for treatment of metabolic diseases such as obesity or diabetes. Thus it might be important to decipher the potential long term impact of such treatment on different physiological func- tions. Indeed, BAs have recently been demonstrated to alter male fertility. Here we demon- strate that in mice with overweight induced by high fat diet, BA exposure leads to increased rate of male infertility. This is associated with the altered germ cell proliferation, default of testicular endocrine function and abnormalities in cell-cell interaction within the seminifer- ous epithelium. Even if the identification of the exact molecular mechanisms will need more studies, the present results suggest that both FXR α and TGR5 might be involved. We believed that this work is of particular interest regarding the potential consequences on future approaches for the treatment of metabolic diseases.
To the Editor:
We would like to draw your attention to some of the drawbacks in a recent article published by Wen et al. in your journal , on NMR-based metabolomics of bile
samples in distinguishing cholangiocarcinoma from benign biliary diseases. The authors performed orthogonal partial least square discriminant analysis (OPLS-DA) of 1 H NMR spectra of bile samples obtained from patients with cholangiocarcinoma and benign biliary diseases. They classified both groups with a sensitivity of 88% and a specificity of 81%. We are currently working on the utility of magnetic resonance spectroscopy in the study of hepatopancreatobiliary diseases , , ,  and  and have noticed some shortcomings in the above study.
strongly suggest that ChREBP activity contributes to cholesterol homeostasis in mice through its effect on CYP8B1 and hence on bile acid composition. The ChREBP-mediated increase in CA and decrease in β-MCA synthesis resulted in more hydrophobic bile that was paralleled by reduced fecal neutral sterol excretion. Because dietary cholesterol intake (data not shown), bil- iary cholesterol excretion (Table 1), and jejunal and ileal mRNA expression of Niemann-Pick C1-like 1, ATP binding cassette subfamily G member 5, ATP binding cassette subfamily G member 8, and acetyl-CoA acetyl- transferase 2 (data not shown) were similar in L-G6pc −/− mice and WT littermates, the reduction in neutral sterol excretion is most likely related to enhanced fractional cholesterol absorption as a consequence of the more hydrophobic bile acid pool in L-G6pc −/− mice. We also show that normalization of bile composition upon hepatic ChREBP knockdown reverses reduced fecal neutral sterol excretion, consistent with the phenotype of Cyp8b1 −/− mice and with the effect of Cyp8b1 inhi- bition in mice. (34,36,43) However, in contrast to what was reported for Cyp8b1 −/− mice fed a high-fat diet, (34,36) fecal fatty acid and energy loss remained unaltered in the current study. In accord with our findings, Cyp8b1 heterozygous knockout mice displaying an intermedi- ate phenotype with regard to bile acid pool composi- tion also did not present changes in fecal calorie loss. (34)
Taken together, our study describes different BA kinetics following an OGTT and a MMTT and identified key determi- nants underlying the large interindividual variability in post- prandial BA profiles. The different patterns of postprandial BA responses, associated with fasting concentrations of BA, al- lowed the classification of the 72 subjects into the 3 major clusters or “metabotypes.” The finding that heterogeneity in 60 preselected genes of BA synthesis and transport explained most of the BA variance argues for these metabotypes as mainly genetically determined and not too much dependent on gut microbiota structure as measured by amplicon sequencing in spite of the known involvement of specific bacterial species in bile acid metabolism in the intestine. Finally, the present study is the first to demonstrate an association between a common genetic variant in the OATP1A2 transporter and postprandial BA kinetics, despite the absence of any effects in the fasting state. Understanding the metabolism of BA in the postprandial state is essential to better understand their roles in human physiology.
Fig. 13 shows isocontours and radial pro ﬁles of the axial velocity
at different azimuthal angles q . We choose the value of the angle q
equal to 0 for the wall (x axis) and p /2 for the symmetry plane (y axis). The velocity pro ﬁle does not vary a lot in ± p /4 sector around the symmetry plane. For angles larger than p /4, the pro ﬁles tends to symmetrize, i.e. the radial position of the maximum velocity shifts toward the center and the inner and outer wall shear stresses tend to be equal. When the angle tends to q 0, i.e. near the walls, the velocity decreases due to the friction. There is the same trend with the inner friction velocity ( Fig. 14 ): the friction velocity does not vary in the quarter near the symmetry plane and decreases near the wall. Since the ﬂuid velocity is higher in the center of the duct, the shear stress is more important in this area.
Standard tests for duct smoke detectors include an evaluation of the sampling system at five velocities in the range of 1.52 m/s to 20.32 m/s. Because concerns had been raised regarding the performance of the sampling tubes being used, surveys of 65 commercial buildings in the Baltimore/Washington area were conducted. The surveys determined that the airflow velocities ranged from 2.06 m/s to 40.64 m/s, with only two of the HVAC systems exceeding the maximum air velocity stipulated in the standard test. Other experiments measured the response of duct smoke detectors as a function of system air velocities of 4.0 m/s to 19 m/s. Over this range, no significant variation in detector performance was observed. The sampling tubes were shown to be effective over the range of velocities typically found in HVAC systems.
However, real life problems are almost always non-deterministic. Uncertainties appear for example due to model errors, manufacturing tolerances, changing environments and noisy measurements. A kriging based method allowing to minimize mean response has been proposed in . In this report this method is applied to the shape optimization of a 2D air conditioning duct. The uncertainties affect the pipe shape. The mean response, expressed in terms of pressure drop and velocity variation at the duct outlet, is minimized in order to obtain a design robust to shape variations.
Fig. 1. Geometry of the lined flow duct. The three bullet points represent pressure sensors.
1.1. Governing equations and problem formulation
The configuration studied in this paper is a two-dimensional partially lined flow duct of height H. The length of the liner is denoted by L. The geometry is depicted in Fig. 1 together with the definitions of the coordinates system. The main flow (denoted with subscript 0) is purely in the axial direction (x-axis) and depends only on y. It is assumed to be subsonic, stationary and homentropic. Moreover, the main density ρ 0 and the sound speed a 0 are taken constant.
Bile acids are synthesized from cholesterol in the liver and play an essential role in cholesterol homeostasis. In the current study, heat exposure of pigs led to a substantial increase in the hepatic concentration of TLCA, TCDCA, TUDCA, THDCA and THCA, and of TCBAs, independent of reduced feed intake. TCBAs are formed through conjugation taurine with bile acids and the concentration of taurine is a major determinant of the proportion of TCBAs in the liver [ 35 , 36 ]. Taurine could increase the amount of TCBAs by the liver in man [ 37 ]. The greater TCBAs concentrations in the liver suggested an increase of taurine in the HS pigs since other BAs were not changed in our current study. The increase of heat dissipation is a significant mechanism for coping with short term heat stress [ 38 ]. The mammalian overall body temperature is regulated by the hypothalamus, which contains high levels of taurine. Taurine is considered an endogenous refrigerant and is involved in the central mechanism of thermoregulation [ 39 ]. Possibly, taurine was released to counteract the resulting hyperthermia.
Overthe next three years, NRC’s team is engaging in research and furtherprotocol development targeted towards the removal ofVOCs by passive panels, as well as particle removal and by-product emissions by in-duct solutions (systems included into largerHVAC units). Overall, efforts are aimed at providing betterinformation forend-users as well as building designers and operators to enable them to make more informed, cost and energy-efficient decisions.
Three different methods can be used to prepare bile-acid-based polyanhydrides. The first developed in our group involved a selective hydrolysis of 3 α-lithocholic acid methyl ester dimers, previously synthesized by linking two lithocholate methyl ester molecules with sebacoyl chloride, yielded carboxylic acid dimer (Figure 1.4, 1). 20 After refluxing in acetic anhydride, the carboxylic acid dimer was transformed to dianhydride (Figure 1.4, 2). This dianhydride was then polycondensed or with a comonomer such as sebacic acid to get homo- or co-polymers with various bile acid contents. The second method to prepare lithocholic-acid-based polyanhydrides, developed by Domb and co-workers, consists of using lithocholic acid as starting material for a reaction with a sebacic anhydride pre-polymer to form a diacid, which contained a lithocholic acid moiety and sebacic acid moiety linked by an ester. 61 This diacid polycondensed with
Bile acids also possess several chiral centers. The modification of hydroxyl and carboxylic groups of bile acids can give rise to a diverse range of bile acid-based compounds. The carboxylic acid group may be esterified, reduced, amidated or subjected to salt formation with metal ions, alkaloids or organic bases. 20, 28 Cholic acid has three OH groups which exhibit very different reactivities depending on their locations at the steroid skeleton. The reactivity of hydroxyl groups towards oxidation is 7-OH > 12-OH > 3-OH. The order of acelylation, hydrolysis, reduction, or hydrogenation is 3-OH > 7-OH > 12- OH. 29 Moreover, the hydroxyl group at C3-position is more reactive than the more sterically hindered OH groups at axial C7- and C12-positions.
There is no field study evidence to show that dust accumulation can cause higher energy consumption, poor HVAC system performance or decreased air flow rates.
With increasing humidity, dust deposition can be enhanced presumably due to two factors: 1) adsorbed water molecules on surfaces have higher affinity to hygroscopic particles; 2) greater particle growth from higher relative humidity increases their gravitational settling velocity (Arundel et al., 1986). No studies have been performed to evaluate bioaerosol deposition onto duct surfaces. However, research in a room chamber (Kanaani et al., 2008) showing similar deposition rates of fungal spores (Aspergillus niger and Penicillium spp) and inanimate particles (canola oil and talcum powder). This indicates that the process may be similar in ducts. Both the aerosol and the bioaerosol deposition rates were found to be a function of particle size.
In conclusion, we report sortase-mediated ligation of human EGF to preformed PEG hydrogels. This enzymatic approach is not only simple and relatively inexpensive, but it also displays high speci ﬁcity and modularity, and may be applied to a variety of PEG hydrogels including those cross-linked in situ in the presence of cells. A compendium of analytical approaches were used to show that the amount of grafted growth factor was readily controlled by the amount of LPRTG substrate incorporated in hydrogels and the amount of GGG-EGF present in solution. While the sortase enzyme was capable of recognizing and processing LPRTG peptides that were incorporated in the hydrogels through Michael-type addition, this method represents a useful tool for speci ﬁc modiﬁcation of any type of hydrogel containing the appropriate substrate. The