Portal Concentrations Research Articles

OR22-01 Sex Differences In Enterohepatic Circulation Mediated By Hepatic FXR And SHP Depletions In Mice

Abstract Disclosure: F. Reichardt: None. C. Galuke: None. S. Anakk: None. Bile acids are transported via the portal vein to the liver after their absorption through the distal intestine mucosa. In hepatocytes, they activate the nuclear receptors, Farnesoid-X-receptor (FXR) and Small Heterodimer Partner (SHP), which exert negative feedback on bile acids synthesis. The aim of this project is to decipher how hepatic FXR/SHP deletion impact BA composition, enterohepatic circulation, and its cross talk with the gut microbiota. Enterohepatic circulation was investigated by measuring total bile acids in intestinal, hepatic tissues and fecal tissues and in portal and systemic blood, using 3-5 months-old fed female and male wildtype (WT) and LDKO (liver specific FXR/SHP depletions) mice. We also examined if intestinal dysmotility mediated the alteration in bile acids absorption by following methylene blue dye progression in overnight fasted WT and LDKO mice. Portal and systemic total bile acids concentrations were higher in LDKO mice compared to WT, despite of no significant change in hepatic and intestinal levels. Sex differences were seen only in LDKO mice with higher systemic and portal concentrations in females compared to males. Intestinal transit time and fecal total bile acids were equivalent between all mice. Intriguingly, we observed that portal bile acids levels correlated to the liver weight to body weight ratio and to cecum weight to body weight ratio, suggesting that bile acids alterations within the enterohepatic loop could be associated to cecal dysbiosis. These preliminary findings highlight altered BA recirculation in LDKO mice compared to WT, but also between females and males LDKO. We hypothesize that these sex-specific modifications are associated with intestinal dysbiosis impacting bile acid compositions, and to test this we will be analyzing the influence of sex, and BA composition on the microbiome. Further investigations using fasted or HFD-fed LDKO and WT mice will help us to better understand the role of hepatic FXR and SHP in bile acids circulation between intestine and liver. Acknowledgement: University of Illinois Urbana-Champaign, American Cancer Society and Cancer Center at Illinois Seed grant Presentation: Saturday, June 17, 2023

Addressing the oxamniquine in vitro-in vivo paradox to facilitate a new generation of anti-schistosome treatments

The antischistosomal drug oxamniquine, OXA, requires activation by a sulfotransferase within the parasitic worm to enable killing. Examination of the pharmacokinetic/pharmacodynamic (PK/PD) relationship for OXA identified an in vitro-in vivo paradox with the maximal clinical plasma concentrations five-to ten-times lower than the efficacious concentration for in vitro schistosomal killing. The parasite resides in the vasculature between the intestine and the liver, and modeling the PK data to determine portal concentrations fits with in vitro studies and explains the required human dose. In silico models were used to predict murine dosing to recapitulate human conditions for OXA portal concentration and time course. Follow-up PK studies verified in mice that a 50–100 mg/kg oral gavage dose of OXA formulated in acetate buffer recapitulates the 20–40 mg/kg dose common in patients. OXA was rapidly cleared through a combination of metabolism and excretion into bile. OXA absorbance and tissue distribution were similar in wild-type and P-gp efflux transporter knockout mice. The incorporation of in vitro efficacy data and portal concentration was demonstrated for an improved OXA-inspired analog that has been shown to kill S. mansoni, S. haematobium, and S. japonicum, whereas OXA is only effective against S. mansoni. Second-generation OXA analogs should optimize both in vitro killing and physiochemical properties to achieve high portal concentration via rapid oral absorption, facilitated by favorable solubility, permeability, and minimal intestinal metabolism.

The short-term effects of berberine in the liver: Narrow margins between benefits and toxicity

Berberine is a plant alkaloid to which antihyperglycemic properties have been attributed. It is also known as an inhibitor of mitochondrial functions. In this work short-term translation of the latter effects on hepatic metabolism were investigated using the isolated perfused rat liver. Once-through perfusion with a buffered saline solution was done. At low portal concentrations berberine modified several metabolic pathways. It inhibited hepatic gluconeogenesis, increased glycolysis, inhibited ammonia detoxification, increased the cytosolic NADH/NAD+ ratio and diminished the ATP levels. Respiration of intact mitochondria was impaired as well as the mitochondrial pyruvate carboxylation activity. These results can be regarded as evidence that the direct inhibitory effects of berberine on gluconeogenesis, mediated by both energy metabolism and pyruvate carboxylation inhibition, represent most likely a significant contribution to its clinical efficacy as an antihyperglycemic agent. However, safety concerns also arise because all effects occur at similar concentrations and there is a narrow margin between the expected benefits and toxicity. Even mild inhibition of gluconeogenesis is accompanied by diminutions in oxygen uptake and ammonia detoxification and increases in the NADH/NAD+ ratio. All combined, desired and undesired effects could well in the end represent a deleterious combination of events leading to disruption of cellular homeostasis.

The rapid transformation of triclosan in the liver reduces its effectiveness as inhibitor of hepatic energy metabolism

Triclosan (5-chloro-2'-[2,4-dichlorophenoxi]-phenol) is a polychlorinated biphenolic antimicrobial, utilized as antiseptic and preservative in hygiene products and medical equipment. Triclosan causes mitochondrial dysfunction (uncoupling, inhibition of electron flow), as demonstrated in isolated rat liver mitochondria. These actions in the mitochondria could compromise energy-dependent metabolic fluxes in the liver. For this reason, the present work aimed at investigating how these effects on isolated mitochondria translate to the whole and intact hepatocyte. For accomplishing this, the isolated perfused rat liver was utilized, a system that preserves both microcirculation and the cell-to-cell interactions. In addition, the single-pass triclosan hepatic transformation was also evaluated by HPLC as well as the direct action of triclosan on gluconeogenic enzymes. The results revealed that triclosan decreased anabolic processes (e.g., gluconeogenesis) and increased catabolic processes (e.g., glycolysis, ammonia output) in the liver, generally with a complex pattern of concentration dependences. Unlike the effects on isolated mitochondria, which occur in the micromolar range, the effects on intact liver required the 10−5 to 10−4 M range. The most probable cause for this behavior is the very high single-pass transformation of triclosan, which was superior to 95% at the portal concentration of 100 μM. The concentration gradient along the sinusoidal bed is, thus, very pronounced and the response of the liver reflects mainly that of the periportal cells. The high rates of hepatic biotransformation may be a probable explanation for the low acute toxicity of triclosan upon oral ingestion.

Age-related alterations of gastric mucosa and estrogen synthesis in rat parietal cells.

The stomach has diverse functions other than gastric acid secretion. Multifaceted studies have investigated age-related changes of the gastrointestinal tract. Nevertheless, little is known about estrogen production changes in gastric parietal cells in rats aged over 3months. We investigated age-related changes in gastric estrogen synthesis and the accompanying changes in liver estrogen receptor from 3 to 24months. Weights of the body, stomach, and liver increased linearly from 3 to 18months, then maintained a constant proportion up to 24months. The gastric mucosa area (in mm2/1mm muscularis mucosa) showed a constant proportion throughout the rats' life. The population of parietal cells immunostained area with H+/K+-ATPase decreased gradually with advancing age. Cells that were immunopositive to aromatase antibody were observed at 3-24months. The expressions of aromatase mRNA and its protein were somewhat lower at 18 and 24months than at 3months. The portal venous estradiol concentration at 12months was 1.5 times higher than that at 3months, and that at 18months was a half of that at 3months. The expression of estrogen receptor mRNA in the liver at 18 and 24months was about 80% of that at 3months. Results suggest that the gastric estrogen production declines with aging, and the liver estrogen receptor is also affected accordingly. Simultaneously, the gastric mucosa continues to express aromatase to maintain liver function(s) throughout the animal's life.

Effects of a Peripherally Restricted Hybrid Inhibitor of CB1 Receptors and iNOS on Alcohol Drinking Behavior and Alcohol-Induced Endotoxemia.

Alcohol consumption is associated with gut dysbiosis, increased intestinal permeability, endotoxemia, and a cascade that leads to persistent systemic inflammation, alcoholic liver disease, and other ailments. Craving for alcohol and its consequences depends, among other things, on the endocannabinoid system. We have analyzed the relative role of central vs. peripheral cannabinoid CB1 receptors (CB1R) using a “two-bottle” as well as a “drinking in the dark” paradigm in mice. The globally acting CB1R antagonist rimonabant and the non-brain penetrant CB1R antagonist JD5037 inhibited voluntary alcohol intake upon systemic but not upon intracerebroventricular administration in doses that elicited anxiogenic-like behavior and blocked CB1R-induced hypothermia and catalepsy. The peripherally restricted hybrid CB1R antagonist/iNOS inhibitor S-MRI-1867 was also effective in reducing alcohol consumption after oral gavage, while its R enantiomer (CB1R inactive/iNOS inhibitor) was not. The two MRI-1867 enantiomers were equally effective in inhibiting an alcohol-induced increase in portal blood endotoxin concentration that was caused by increased gut permeability. We conclude that (i) activation of peripheral CB1R plays a dominant role in promoting alcohol intake and (ii) the iNOS inhibitory function of MRI-1867 helps in mitigating the alcohol-induced increase in endotoxemia.

1787-P: Insulin Pulse Characteristics Do Not Alter Hepatic Glucose Metabolism and Insulin Action

Insulin is secreted into the portal vein in a pulsatile manner. Portal vein insulin concentrations directly and rapidly alter endogenous glucose production (EGP). Pulse frequency has been inversely correlated with hepatic insulin action in some, but not all, human studies. Indeed, increased pulse disorderliness, decreased secretory burst mass and decreased pulse frequency have been observed in type 2 diabetes, in aging and in obesity. In dogs, disruption of pulsatile insulin secretion is associated with defects in hepatic insulin action. As part of a series of experiments examining the mechanisms underlying prediabetes, we studied 29 nondiabetic subjects (BMI 28 ± 1 Kg/m2) on 2 occasions. On one occasion, EGP was measured using [3-3H]glucose after an overnight fast (14.2 ± 0.5μmol/kg/min) and during a euglycemic clamp (6.8 ± 1.1μmol/kg/min). The deuterated water method was used to estimate the contribution of gluconeogenesis to EGP. On a separate study day we utilized nonparametric stochastic deconvolution of frequently sampled peripheral C-peptide concentrations during fasting to reconstruct portal insulin secretion. In addition to measuring basal and pulsatile insulin secretion, we used Approximate Entropy (ApEn) to measure orderliness and a Fourier transform to measure the average and the dispersion of insulin pulse frequency. The gradient of Loge EGP vs. Loge insulin in each individual (-1.2 ± 0.5) was used as a measure of hepatic insulin action. Basal secretion (126 ± 8 pmol/min, R2=0.04), pulse amplitude (41 ± 38 pmol/min, R2=0.02), ApEn (1.14 ± 0.03, R2=0.01), pulse interval (5.7 ± 0.4 min, R2<0.01) and frequency dispersion (0.47 ± 0.01, R2<0.01) did not correlate (all p > 0.10) with hepatic insulin action. Suppression of gluconeogenesis by insulin also did not correlate with fasting insulin pulse characteristics. Overall, our data demonstrate that insulin pulse characteristics do not directly alter the sensitivity of EGP and gluconeogenesis to insulin in humans. Disclosure M.C. Laurenti: None. C. Dalla Man: Research Support; Self; Sanofi-Aventis Deutschland GmbH. R.T. Varghese: None. J. Jones: None. C. Barosa: None. R.A. Rizza: None. A. Matveyenko: None. G. De Nicolao: None. C. Cobelli: None. A. Vella: Advisory Panel; Self; vTv Therapeutics, Zealand Pharma A/S. Research Support; Self; Novo Nordisk A/S, Xeris Pharmaceuticals, Inc. Funding National Institutes of Health (DK78646, DK116231)

Оценка корреляции выраженности портальной гипертензии и концентрации кишечного эндотоксина у пациентов с алкогольной болезнью печени

Оценка корреляции выраженности портальной гипертензии и концентрации кишечного эндотоксина у пациентов с алкогольной болезнью печени

P-glycoprotein activation by 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) in rat distal ileum: ex vivo and in vivo studies

In vitro studies showed that 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) increases P-glycoprotein (P-gp) expression and activity in Caco-2 cells, preventing xenobiotic toxicity. The present study aimed at investigating TX5 effects on P-gp expression/activity using Wistar Han rats: a) in vivo, evaluating intestinal P-gp activity; b) ex vivo, evaluating P-gp expression in ileum brush border membranes (BBM) and P-gp activity in everted intestinal sacs; c) ex vivo, evaluating P-gp activity in everted intestinal sacs of the distal and proximal ileum. TX5 (30 mg/kg, b.w.), gavage, activated P-gp in vivo, given the significant decrease in the AUC of digoxin (0.25 mg/kg, b.w.). The efflux of rhodamine 123 (300 μM), a P-gp fluorescent substrate, significantly increased in TX5-treated everted sacs from the distal portion of the rat ileum, when P-gp activity was evaluated in the presence of TX5 (20 μM), an effect abolished by the P-gp inhibitor verapamil (100 μM). No increases on P-gp expression or activity were found in TX5-treated BBM of the distal ileum and everted distal sacs, respectively, 24 h after TX5 (10 mg/kg, b.w.) administration. In vivo, no differences were found on digoxin portal concentration between control (digoxin 0.025 mg/kg, b.w., intraduodenal) and TX5-treated (digoxin+TX5 20 μM, intraduodenal) rats. The observed discrepancies in digoxin results can be related to differences in TX5 dose administered and used methodologies. Thus, the results show that TX5 activates P-gp at the distal portion of the rat ileum, and, at the higher dose tested (30 mg/kg, b.w.), seems to modulate in vivo the AUC of P-gp substrates.

1878-P: Glucagon Is neither Necessary nor Sufficient for Ketosis in Mice

The current consensus mechanism for hepatic ketogenesis posits a key role for islet hormones, with insulin inhibiting and glucagon stimulating formation of ketone bodies. In this model the action of glucagon in the presence of low portal insulin concentrations causes ketosis. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are effective for lowering glucose in diabetic patients, and cause a relative insulinopenia. These agents have been described to increase ketone production, and have been associated with cases of diabetic ketoacidosis. SGLT2i have been recently reported to stimulate islet α-cells, suggesting the hypothesis that SGLT2i-induced glucagon secretion drives ketogenesis. To test this hypothesis, mice were given the SGLT2i dapagliflozin (dapa) in the presence or absence of glucagon signaling. Fasting-induced ketosis was used as a positive control. In both dapa-treated mice and 16 hour fasted mice, blood glucose decreased to the 4-5 mM range, β-OHB increased 2-3 fold, and NEFA rose 30-50%. Fasting had minimal effects on plasma glucagon, but dapa increased glucagon concentrations, albeit at a delayed rate compared to changes in glycemia, β-OHB, or NEFAs. Interruption of glucagon signaling with either: 1) a glucagon receptor antagonist (GRA); or 2) mice with a deletion of the proGlucagon gene had no effect on the development of ketosis in response to dapa or fasting, indicating that glucagon is not necessary for ketosis in these conditions. To test its sufficiency, glucagon (20µg/kg) was given to fed mice, 16 hour fasted mice, dapa-treated mice, and mice with insulin receptor blockade (IRB). Fasting, dapa and IRB all increased β-OHB significantly but glucagon did not add to this. In contrast, epinephrine significantly elevated ketone levels under these conditions. These findings indicate that the current model of the regulation of ketogenesis needs to be reconsidered, and that in mice glucagon does not have a significant role in this process. Disclosure M. Capozzi: None. R. Coch: None. J.B. Wait: None. J.J. Koech: None. J. Campbell: Research Support; Self; Eli Lilly and Company. Speaker's Bureau; Self; Merck Sharp & Dohme Corp. D.A. D'Alessio: Advisory Panel; Self; Eli Lilly and Company. Research Support; Self; Eli Lilly and Company, Merck & Co., Inc. Funding National Institutes of Health (F32-DK116542)

Ascorbic acid deficiency increases hepatic expression of acute phase proteins through the intestine-derived IL-6 and hepatic STAT3 pathway in ODS rats

We have previously shown that ascorbic acid (AsA) deficiency elevates hepatic expression of acute phase proteins (APPs), inflammatory markers, in Osteogenic Disorder Shionogi (ODS) rats, which are unable to synthesize AsA. However, the precise mechanisms of this elevation are unknown. Signal transducer and activator of transcription 3 (STAT3) is one of the transcription factors inducing the expression of APPs and is activated by several cytokines including interleukin-6 (IL-6). The aim of this study was to determine whether AsA deficiency stimulates hepatic STAT3 activation and increases intestinal production of proinflammatory cytokines such as IL-6. Male ODS rats (6 weeks old) were fed either a basal diet containing 300 mg AsA/kg (control group) or an AsA-free diet (AsA-deficient group) for 18 days. AsA deficiency gradually and simultaneously elevated both mRNA levels of APPs (haptoglobin, α1-acid glycoprotein, C-reactive protein and α2-macroglobulin) and nuclear level of phosphorylated STAT3 (activated STAT3) in the liver. These results showed that the AsA-deficiency-induced expression of hepatic APPs is stimulated by proinflammatory cytokines activating STAT3. On day 14, AsA deficiency significantly elevated IL-6 mRNA level in the ileum and the concentration of IL-6 in portal blood. Furthermore, the portal concentration of IL-6 positively correlated with hepatic mRNA levels of STAT3-regulated genes. These findings suggest that IL-6, produced in the intestine as a result of AsA deficiency, is recruited to the liver via the portal vein and contributes to hepatic STAT3 activation and the elevated expression of APPs.

Circulating Fibroblast Growth Factor 19 in Portal and Systemic Blood

Bile acid homeostasis is essential and imbalance may lead to liver damage and liver failure. The bile acid induced intestinal factor fibroblast growth factor 19 (FGF19) has been identified as a key protein for mediating negative feedback inhibition of bile acid synthesis. The aim of the study was to define FGF19 and bile acid concentrations in portal and systemic blood in the fasted and postprandial state. We also addressed the question if physiological portal levels of FGF19 can be extrapolated from the concentration in systemic blood. Portal and systemic blood was collected from 75 fasted patients undergoing liver surgery and from three organ donors before and after enteral nutrition. Serum concentration of FGF19 was determined with ELISA and bile acid concentration with gas chromatography-mass spectrometry. Concentration of bile acids was twice as high in portal compared to systemic blood in the fasted group and 3-5 times higher in the postprandial group. FGF19 increased after enteral nutrition but did not differ between portal and systemic blood, in either group. In addition, a strong, positive correlation between bile acids and FGF19 was found. Our results confirm that bile acids drive the postprandial increase of circulating FGF19 but a hepatic clearance of FGF19 is unlikely. We conclude that systemic concentrations of FGF19 reflect portal concentrations of FGF19.

Dietary fructose causes defective insulin signalling and ceramide accumulation in the liver that can be reversed by gut microbiota modulation

ABSTRACTObjective: The link between metabolic derangement of the gut–2013liver–visceral white adipose tissue (v-WAT) axis and gut microbiota was investigated.Methods: Rats were fed a fructose-rich diet and treated with an antibiotic mix. Inflammation was measured in portal plasma, ileum, liver, and v-WAT, while insulin signalling was analysed by measuring levels of phosphorylated kinase Akt. The function and oxidative status of hepatic mitochondria and caecal microbiota composition were also evaluated.Results: Ileal inflammation, increase in plasma transaminases, plasma peroxidised lipids, portal concentrations of tumour necrosis factor alpha, lipopolysaccharide, and non-esterified fatty acids, were induced by fructose and were reversed by antibiotic. The increased hepatic ceramide content, inflammation and decreased insulin signaling in liver and v-WAT induced by fructose was reversed by antibiotic. Antibiotic also blunted the increase in hepatic mitochondrial efficiency and oxidative damage of rats fed fructose-rich diet. Three genera, Coprococcus, Ruminococcus, and Clostridium, significantly increased, while the Clostridiaceae family significantly decreased in rats fed a fructose-rich diet, and antibiotic abolished these variationsConclusions: When gut microbiota modulation by fructose is prevented by antibiotic, inflammatory flow from the gut to the liver and v-WAT are reversed.

Pharmacokinetics and the effect of heat on intraperitoneal pemetrexed using a murine model

BackgroundPemetrexed is a systemic chemotherapeutic agent used in the treatment of malignant mesothelioma. This drug represents a potentially promising intraperitoneal (IP) agent to use for hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of peritoneal mesothelioma. However, this has yet to be supported by preclinical studies. Therefore, we aimed to study the effect of pemetrexed dose and perfusion temperature on the resultant pemetrexed concentration in 3 different compartments (systemic circulation, portal circulation and peritoneal tissues) using a murine model. MethodsUnder general anesthesia, 29 Sprague-Dawley rats were submitted to 3 different doses of IP pemetrexed (500, 1000 and 1500 mg/m2) combined with 3 different perfusion temperatures (37, 40 and 43 °C) for a total duration of 25 min. At the end of perfusion, samples in different compartments (systemic circulation, portal circulation and peritoneum) were harvested and concentrations of pemetrexed were measured using high performance liquid chromatography. ResultsWith increasing dose of IP pemetrexed, higher concentrations were measured in the 3 compartments tested. In peritoneal cells, the difference between IP doses of 500 and 1000 mg/m2 (2.03 vs. 19.17 μg/g, p < 0.001) was greater than the difference between 1000 and 1500 mg/m2 (19.17 vs. 22.80 μg/g, p = 0.027). When the perfusion temperature increased, we observed a proportional rise of pemetrexed concentration in both the portal and systemic compartments; while in the peritoneal cells, the pemetrexed concentration increased up to 40 °C, after which it plateaued. ConclusionBoth heat and increasing doses of IP pemetrexed enhance peritoneal cell concentration of pemetrexed. However, for temperatures above 40 °C, pemetrexed concentration reached a plateau in peritoneal cells. Systemic and portal concentrations increased proportionally with both increasing temperatures and IP doses. We believe these results should be taken into consideration for the design of an eventual clinical study in humans.

Pore alterations of the endothelial lining of rat fenestrated intestinal capillaries exposed to acute stress.

Stress-induced inflammatory responses in the portal system are characterized by elevations in serum concentrations of interleukin-6 (IL-6) and endotoxins such as lipopolysaccharides (LPS). LPS translocation from the intestinal to the capillary lumen occurs via LPS endocytosis by the capillary endothelium. Because the capillary endothelium of the small intestinal submucosa is fenestrated, we determined the role of pore modifications within the fenestrated endothelium in relaying inflammatory stress responses in the portal vein. We evaluated changes in the diameter and density of endothelial pores of the lamina propria of intestinal villi induced by continuous light (CL) exposure for 48 h and the correlation between these changes and serum IL-6 concentration in the portal vein in a rat model. We found significant increases in both the pore diameter and density, accompanied by a significant increase in portal IL-6 concentration; these changes were significantly attenuated by pretreatment with propranolol, a beta adrenergic receptor antagonist. In contrast, intravenous noradrenaline administration mimicked CL-induced modifications of the diameter and density of pores and the elevation of portal vein IL-6 concentration. These findings suggested that stress-induced inflammatory responses in the portal system may be a part of the modifications of the endothelial pores triggered by sympathetic activation.

POSSIBLE CHANGES IN THE CENTRAL HEMODYNAMICS IN PORTAL HYPERTENSION DUE TO LIVER CIRRHOSIS OF VIRAL ETIOLOGY WITH DIFFERENT LEVELS OF CYTOKINES

Aim. To study possible variants of changes in structural and functional parameters of central hemodynamics in liver cirrhosis classes A, B, C (Child– Pugh) to improve the early diagnostics of extrahepatic complications. Material and methods. Parameters of central hemodynamics were studied in 107 patients with liver cirrhosis of viral etiology classes A, B, C (ChildPugh) with different levels of serum interleukins (interleukin-2, interleukin-6, tumor necrosis factor alpha). Results. Significant changes in the central hemodynamics parameters were not revealed in liver cirrhosis of classes A and B. In patients with liver cirrhosis of class С the following significant changes of the left and right heart were found: thickening of the interventricular septum and left ventricular posterior wall up to 12.9Ѓ}1.3 and 13.5Ѓ}1.4 mm respectively; increase in left atrium up to 43.1Ѓ}4.7 mm; right ventricular dilatation up to 38.6Ѓ}4.1 mm and pulmonary artery up to 35.7Ѓ}3.1 mm with an increase in pressure in it up to 35.7Ѓ}3.1 mm Hg. The rate and variants of changes in structural and functional parameters of central hemodynamics correlated with the stages of the liver cirrhosis compensation and the interleukins serum levels. Conclusion. Changes in parameters of central hemodynamics in liver cirrhosis depends on the stage of compensation. The most pronounced systolic and diastolic myocardial dysfunctions were observed in cirrhosis Class C, with high levels of portal pressure and high concentrations of serum interleukins. Concentric remodeling of the left ventricular and isolated ventricular septal hypertrophy were the worst types of the left ventricular remodeling. These variants of ventricular geometry were accompanied by the most severe impairments of diastolic function.

Cholesterol-Lowering Effect of Calcium Alginate in Rats.

We examined whether calcium alginate (Ca-Alg) reduces blood cholesterol levels in rats fed a high-cholesterol diet. First, we examined taurocholate adsorption in vitro by various types of sodium alginate (Na-Alg). High molecular-weight, guluronic acid-rich Na-Alg showed the greatest adsorption of taurocholate, and therefore the corresponding Ca-Alg was chosen for the in vivo study. Rats were fed a high-cholesterol diet or a Ca-Alg-containing diet for 2 weeks. Body weight and diet intake were measured, and the general condition of the animals was monitored during this period. After 14 d, the plasma concentration of cholesterol, portal plasma concentration of bile acid, and bile acid in feces were measured. The plasma concentration of cholesterol was significantly reduced in rats fed a 2% Ca-Alg-containing diet. Furthermore, the portal concentration of bile acid was significantly lowered in the 2% Ca-Alg group. A tendency for a Ca-Alg concentration-dependent increase in fecal excretion of bile acid was also seen, although it was not statistically significant. While several changes in biochemical parameters and histopathological findings were observed, all the values remained within the physiological range. These results indicate that Ca-Alg is effective in reducing plasma cholesterol. A possible mechanism would be enhanced fecal excretion of bile acid due to reduced intestinal reabsorption, which in turn might stimulate bile acid synthesis from cholesterol in the liver, leading to a decrease in plasma cholesterol.

Butyrylated starch affects colorectal cancer markers beneficially and dose-dependently in genotoxin-treated rats

Population studies suggest that greater dietary fiber intake may lower colorectal cancer (CRC) risk, possibly through the colonic bacterial fermentative production of butyrate. Butyrylated starch delivers butyrate to the colon of humans with potential to reduce CRC risk but high doses may exacerbate risk through promoting epithelial proliferation. Here we report the effects of increasing dietary butyrylated high amylose maize starch (HAMSB) on azoxymethane (AOM) induced distal colonic DNA damage, cell proliferation, mucus layer thickness and apoptosis in rats. Five groups of 15 rats were fed AIN-93G based diets containing 0–40% HAMSB for 4 weeks then injected with (AOM) and killed 6 hours later. Large bowel total SCFA, acetate and butyrate pools and hepatic portal venous plasma total SCFA, acetate and butyrate concentrations were higher with greater HAMSB intake. Distal colonic epithelial apoptotic index and colonic mucus thickness increased, while DNA single strand breaks decreased dose-dependently with greater HAMSB intake. Colonocyte proliferation rates were unaffected by diet. These data suggest that increasing large bowel butyrate may reduce the risk of CRC in a dose dependent manner by enhancing apoptotic surveillance in the colonic epithelium for damaged cells without promoting the risk of tumorigenesis through increased cell proliferation.

Integrated metabolic spatial‐temporal model for the prediction of ammonia detoxification during liver damage and regeneration

The impairment of hepatic metabolism due to liver injury has high systemic relevance. However, it is difficult to calculate the impairment of metabolic capacity from a specific pattern of liver damage with conventional techniques. We established an integrated metabolic spatial-temporal model (IM) using hepatic ammonia detoxification as a paradigm. First, a metabolic model (MM) based on mass balancing and mouse liver perfusion data was established to describe ammonia detoxification and its zonation. Next, the MM was combined with a spatial-temporal model simulating liver tissue damage and regeneration after CCl4 intoxication. The resulting IM simulated and visualized whether, where, and to what extent liver damage compromised ammonia detoxification. It allowed us to enter the extent and spatial patterns of liver damage and then calculate the outflow concentrations of ammonia, glutamine, and urea in the hepatic vein. The model was validated through comparisons with (1) published data for isolated, perfused livers with and without CCl4 intoxication and (2) a set of in vivo experiments. Using the experimentally determined portal concentrations of ammonia, the model adequately predicted metabolite concentrations over time in the hepatic vein during toxin-induced liver damage and regeneration in rodents. Further simulations, especially in combination with a simplified model of blood circulation with three ammonia-detoxifying compartments, indicated a yet unidentified process of ammonia consumption during liver regeneration and revealed unexpected concomitant changes in amino acid metabolism in the liver and at extrahepatic sites. The IM of hepatic ammonia detoxification considerably improves our understanding of the metabolic impact of liver disease and highlights the importance of integrated modeling approaches on the way toward virtual organisms.

Kinetics of the transformation of n-propyl gallate and structural analogs in the perfused rat liver

n-Propyl gallate and its analogs are used in foods and other products to prevent oxidation. In the liver the compound exerts several harmful effects, especially gluconeogenesis inhibition. The mode of transport and distribution of n-propyl gallate and its kinetics of biotransformation have not yet been investigated. To fill this gap the transformation, transport and distribution of n-propyl gallate and two analogs were investigated in the rat liver. Isolated perfused rat liver was used. n-Propyl gallate, methyl gallate, n-octyl gallate and transformation products were quantified by high pressure-liquid chromatography coupled to fluorescence detection. The interactions of n-propyl gallate and analogs with the liver presented three main characteristics: (1) the hydrolytic release of gallic acid from n-propyl gallate and methyl gallate was very fast compared with the subsequent transformations of the gallic acid moiety; (2) transport of the esters was very fast and flow-limited in contrast to the slow and barrier-limited transport of gallic acid; (3) the apparent distribution volume of n-propyl gallate, but probably also of methyl gallate and n-octyl gallate, greatly exceeded the water space in the liver, contrary to the gallic acid space which is smaller than the water space. It can be concluded that at low portal concentrations (<50μM) the gallic acid esters are 100% extracted during a single passage through the liver, releasing mainly gallic acid into the systemic circulation. For the latter a considerable time is required until complete biotransformation. The exposure of the liver to the esters, however, is quite prolonged due to extensive intracellular binding.