Bacterial translocation in acute liver failure induced by 90 per cent hepatectomy in the rat

Narrative Review of Probiotic Use on the Recovery of Postoperative Patients with Esophageal Cancer

PURPOSE OF REVIEW

This narrative review discusses the significance of probiotic therapy in the postoperative care of patients with esophageal cancer and its role as an adjunct therapy to other treatment modalities for esophageal cancer.

RECENT FINDINGS

As such, there is an emerging need to address any malnutrition and gastrointestinal problems occurring in these patients which tend to have a strong negative impact on their prognosis. Probiotic effects on esophageal cancer biomarkers suggest that there is a positive correlation between these two factors. However, the beneficial effects remain controversial and warrant further investigation. Probiotics, now being widely utilized as postoperative therapy in some carcinomas of the gastrointestinal tract such as gastric cancer and colorectal cancer, have been shown in some clinical studies to positively impact the nutritional status of patients with esophageal cancer. Postoperative care among patients suffering from esophageal cancer is a very crucial aspect in the survival of these patients.

Liver Regeneration in Acute on Chronic Liver Failure

Liver regeneration is a multifaceted process by which the organ regains its original size and histologic organization. In recent decades, substantial advances have been made in our understanding of the mechanisms underlying regeneration following loss of hepatic mass. Liver regeneration in acute liver failure possesses several classic pathways, while also exhibiting unique differences in key processes such as the roles of differentiated cells and stem cell analogs. Here we summarize these unique differences and new molecular mechanisms involving the gut-liver axis, immunomodulation, and microRNAs with an emphasis on applications to the patient population through stem cell therapies and prognostication.

Predictors of Liver Failure in Non-Cirrhotic Patients Undergoing Hepatectomy

BACKGROUND

Post-hepatectomy liver failure (PHLF) is associated with high mortality following liver resection. There have been limited studies evaluating predictors of PHLF and clinically significant PHLF in non-cirrhotic patients.

METHODS

This was a retrospective cohort study using the National Surgical Quality Improvement Program database (NSQIP) to evaluate 8,093 non-cirrhotic patients undergoing hepatectomy from 2014 to 2018. Primary endpoints were PHLF and clinically significant PHLF (PHLF grade B or C).

RESULTS

Among all patients, 4.74% (n = 383) developed PHLF and 2.5% clinically significant PHLF (n = 203). The overall 30-day mortality was 1.35% (n = 109), 11.5% (n = 44) in patients with PHLF, and 19.2% in those with clinically significant PHLF. Factors associated with PHLF were: metastatic liver disease (OR = 1.84, CI = 1.14-2.98), trisectionectomy (OR = 3.71, CI = 2.59-5.32), right total lobectomy (OR = 4.17, CI = 3.06-5.68), transfusions (OR = 1.99, CI = 1.52-2.62), organ/space SSI (OR = 2.84, CI = 2.02-3.98), post-operative pneumonia (OR = 2.43, CI = 1.57-3.76), sepsis (OR = 2.27, CI = 1.47-3.51), and septic shock (OR = 5.67, CI = 3.43-9.36). Patients who developed PHLF or clinically significant PHLF had 2-threefold increased risk of perioperative mortality. Post-hepatectomy renal failure (OR = 8.47, CI = 3.96-18.1), older age (OR = 1.04, CI = 1.014-1.063), male sex (OR = 1.83, CI = 1.07-3.14), sepsis (OR = 2.96, CI = 1.22-7.2), and septic shock (OR = 3.92, CI = 1.61-9.58) were independently associated with 30-mortality in patients with clinically significant PHLF.

CONCLUSION

PHLF in non-cirrhotic patients increased the risk of perioperative mortality and is associated with the extent of hepatectomy and infectious complications. Careful evaluation of the liver remnant, antibiotic prophylaxis, nutritional assessment, and timely management of post-operative infections could decrease major morbidity and mortality following hepatectomy.

Contribution of hepatobiliary scintigraphy in assessing ALPPS most suited timing

To reduce post-hepatectomy liver failure (PHLF), associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been recently developed for patients with a limited future remnant liver (FRL). Nevertheless, high morbi-mortality rates have been reported . The current study aimed to analyze the kinetics of FRL function in patients who were offered ALPPS. Serial SPECT (99 m)Tc-mebrofenin hepatobiliary scintigraphy (HBS) was performed in all patients before and after surgery as well as at inter-stage to quantitatively assess hepatic function [total liver (TL) and FRL]. Patients were offered ALPPS for colorectal liver metastases (CLMs) (n = 6) and gallbladder carcinoma (n = 1). The data of delta of function or volume, expressed as (postoperative FRL - preoperative FRL/preoperative FRL) were compared to those derived from HBS of patients referred to the university hospital of Lille for one-stage major hepatectomy (n = 93). Additionally, the intrinsic liver function (i.e. function per unit of volume) was used to assess the regeneration rate. All but one patient had an anticipated FRL to body weight ratio (FRLBWR) ≤0.5%. Inter-stages HBS showed a progressive attenuation of the functional value of the excluded hepatic segments in favour of the FRL for all patients. Overall, there was a drop of total liver function contrasting with subnormal passive biochemical tests. Notably, the increase in FRL function between ALPPS stages [+12.5% (4.2-28.6%)] was lower than the volumetric gain [+42.6% (18.3-110.2%)] and inferior to that observed after one-stage major hepatectomy [+41.7% (-38.6 to +158.33%)]. This resulted in a drop of the FRL intrinsic liver function in ALPPS patients, of whom one died from PHLF. Our study enhances the importance of assessing liver function along with volume during ALPPS procedure and supports HBS as a suitable and reliable method, including a valuable contribution to determine most appropriate stage 2 surgical timing.

Role of stress and intestinal barrier dysfunction in inflammatory bowel disease

Stress, provoked by stressors, can cause a series of physical and psychological reactions and initiate both central and peripheral responses to maintain homeostasis. The causes of inflammatory bowel disease are poorly understood, which may involve complex interactions among environmental, psychological, dietary, immunological and pharmacological factors. This paper reviews the epidemiological and clinical data on how stress may precipitate in the attack, relapse and recurrence of inflammatory bowel disease. A possible biological mechanism is the impaired intestinal barrier including physical barrier, biologic barrier, immunological barrier and chemical barrier. Clinical epidemiological data and many animal studies show that stress may reduce mucous secretion and increase colonic permeability, which are the characteristic changes of inflammatory bowel disease. Understanding the relationship between stress and inflammatory bowel disease can improve the health related quality of life and lower the medical cost.

Probiotics and Synbiotics Decrease Postoperative Sepsis in Elective Gastrointestinal Surgical Patients: a Meta-Analysis

BACKGROUND

The health benefits of probiotics and synbiotics are well established in healthy adults, but their role in preventing postoperative sepsis remains controversial. This meta-analysis assesses the impact of probiotics and synbiotics on the incidence of postoperative sepsis in gastrointestinal (GI) surgical patients.

METHODS

A comprehensive literature search of all published randomized control trials (RCTs) was conducted using PubMed, Cochrane Central Registry of Controlled Trials, and Google Scholar (1966-2015). Inclusion criteria included RCTs comparing the use of any strain or dose of a specified probiotic/synbiotic with placebo or a "no treatment" control group. The incidence of postoperative sepsis (within 1 month of surgery) and postoperative mortality were analyzed.

RESULTS

Fifteen RCTs involving 1201 patients (192 receiving probiotics, 413 receiving synbiotics, and 596 receiving placebo) were analyzed. Overall, probiotic and synbiotic uses significantly reduced the risk of developing postoperative sepsis by 38 % (relative risk (RR) = 0.62, 95 % confidence interval (CI) 0.52-0.74, p < 0.001).

CONCLUSIONS

The use of probiotic/synbiotic supplementation is associated with a significant reduction in the risk of developing postoperative sepsis in patients undergoing elective GI surgery. Probiotic/synbiotic supplementation is a valuable adjunct in the care of patients undergoing GI surgery. Additional studies are required to determine the optimal dose and strain of probiotic/synbiotic.

Bioartificial liver attenuates intestinal mucosa injury and gut barrier dysfunction after major hepatectomy: Study in a porcine model

BACKGROUND

The aim of this study was to evaluate whether bioartificial liver support can attenuate gut mucosa injury in a porcine model of posthepatectomy liver dysfunction.

METHODS

Posthepatectomy liver failure was induced in pigs combining major (70%) liver resection and ischemia/reperfusion injury. An ischemic period of 150 minutes was followed by reperfusion for 24 hours. Animals were divided randomly into 2 groups: a control group (n = 6) that received standard critical care and a bioartificial liver support group (Hepat, n = 6) that were subjected to extracorporeal liver support for 6 hours during reperfusion. Intestinal mucosal injury, bacterial translocation, and endotoxin translocation were evaluated in all animals. Intestinal mucosa was also evaluated with markers of oxidative injury and immunohistochemical staining for caspase 3.

RESULTS

When compared with median values, the control group, animals in the Hepat group had a lesser intestinal mucosal injury score (4.0 [range:2.0-5.0] vs 1.0 [range:1.0-2.0]; P < .01), decreased bacterial translocation in the portal and the systemic circulation at 24 hours of reperfusion (P < .05), and decreased portal and systemic endotoxin levels at 24 hours (P < .05). At 24 hours after reperfusion, mucosal protein carbonyls and malondialdehyde levels were decreased in Hepat animals (0.57 nmol/mg [range:0.32-0.70] vs 0.33 nmol/mg [range:0.03-0.53] and 3.85 nmol/mg [range:3.01-6.43] vs 3.27 nmol/mg [range:1.46-3.55], respectively; P < .05). There was no difference in tissue caspase staining.

CONCLUSION

Bioartificial liver support seems to attenuate intestinal mucosal injury and gut barrier dysfunction after major hepatectomy.

CSF1 Restores Innate Immunity After Liver Injury in Mice and Serum Levels Indicate Outcomes of Patients With Acute Liver Failure

BACKGROUND & AIMS

Liver regeneration requires functional liver macrophages, which provide an immune barrier that is compromised after liver injury. The numbers of liver macrophages are controlled by macrophage colony-stimulating factor (CSF1). We examined the prognostic significance of the serum level of CSF1 in patients with acute liver injury and studied its effects in mice.

METHODS

We measured levels of CSF1 in serum samples collected from 55 patients who underwent partial hepatectomy at the Royal Infirmary Edinburgh between December 2012 and October 2013, as well as from 78 patients with acetaminophen-induced acute liver failure admitted to the Royal Infirmary Edinburgh or the University of Kansas Medical Centre. We studied the effects of increased levels of CSF1 in uninjured mice that express wild-type CSF1 receptor or a constitutive or inducible CSF1-receptor reporter, as well as in chemokine receptor 2 (Ccr2)-/- mice; we performed fate-tracing experiments using bone marrow chimeras. We administered CSF1-Fc (fragment, crystallizable) to mice after partial hepatectomy and acetaminophen intoxication, and measured regenerative parameters and innate immunity by clearance of fluorescent microbeads and bacterial particles.

RESULTS

Serum levels of CSF1 increased in patients undergoing liver surgery in proportion to the extent of liver resected. In patients with acetaminophen-induced acute liver failure, a low serum level of CSF1 was associated with increased mortality. In mice, administration of CSF1-Fc promoted hepatic macrophage accumulation via proliferation of resident macrophages and recruitment of monocytes. CSF1-Fc also promoted transdifferentiation of infiltrating monocytes into cells with a hepatic macrophage phenotype. CSF1-Fc increased innate immunity in mice after partial hepatectomy or acetaminophen-induced injury, with resident hepatic macrophage as the main effector cells.

CONCLUSIONS

Serum CSF1 appears to be a prognostic marker for patients with acute liver injury. CSF1 might be developed as a therapeutic agent to restore innate immune function after liver injury.

Beneficial effects of green tea catechin on massive hepatectomy model in rats

BACKGROUND

Green tea catechin, especially epigallocatechin gallate (EGCG), is a well-known scavenger of reactive oxygen species and it may also function as an antioxidant through modulation of transcriptional factors and enzyme activities.

METHODS

Green tea extract (GTE®) which contained numerous EGCG was used. Wistar rats were performed 90 % hepatectomy and classified into 2 groups with (GTEHx, n = 25) or without GTE treatment (Hx, n = 25) and sacrificed at 1, 3, 7 and 14 days after operations. All rats had free access to drinking water supplemented with or without GTE from the 7th pre-operative day. Liver regeneration, hepatic inducible nitric oxide synthase (iNOS), anti-oxidative enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px)] and inflammatory markers [cyclooxygenase-2 (COX-2), nuclear factor kappa B (NFκB), tumor necrosis factor-α (TNF-α)] were investigated.

RESULTS

The liver weight to body weight ratio (p < 0.01), proliferating cell nuclear antigen labeling index (p < 0.05) and phosphorylated extracellular signal-regulated kinase 1/2 (p < 0.05) at day 1 in the GTEHx group significantly increased compared to the Hx group. Hepatic iNOS levels at day 1 significantly decreased (p < 0.01) in the GTEHx group. Hepatic SOD, CAT and GSH-Px levels at day 1 significantly increased (SOD: p < 0.01, CAT and GSH-Px: p < 0.05) in the GTEHx group. In contrast, COX-2, NFκB and TNF-α levels at day 1 significantly decreased (COX-2: p < 0.01, NFκB and TNF-α: p < 0.05) in the GTEHx group.

CONCLUSIONS

GTE pretreatment stimulated liver regeneration and improved liver damage after massive hepatectomy through anti-oxidative and anti-inflammatory effects. Green tea catechin might have the potential to attenuate liver dysfunction in early stage after massive hepatectomy.

Mechanisms of splenic hypertrophy following hepatic resection

BACKGROUND

Following hepatic resection, liver regeneration has been associated with concurrent splenic hypertrophy. The mechanisms of this phenomenon are unknown, may be multiple and include: splanchnic sequestration caused by a reduction in the hepatic mass; hepatic growth factors that may indirectly act on the spleen, and the redistribution of the total reticuloendothelial system.

METHODS

Seventy-five patients (40 males; median age: 60 years) who underwent minor (16%) or major (84%) hepatectomy between September 2004 and October 2009 were included. Prospective measurements of liver and spleen volumes were obtained preoperatively and postoperatively 1 month after hepatectomy using computed tomography (CT). The future remnant liver volume (RLV) was calculated on preoperative CT and the extent of resection was expressed as the RLV divided by total liver volume (TLV). Liver and spleen hypertrophy were expressed according to the absolute gain or relative increase in the initial volumes (%).The presence of fibrosis >F1, associated extrahepatic resection (except minor resections), and previous hepatectomy (major or minor) within 3 months represented exclusion criteria.

RESULTS

Mean ± standard deviation (SD) liver volume at 1 month was higher than RLV (1187 ± 286 cm(3) versus 764 ± 421 cm(3) ; P < 0.001). Mean ± SD splenic volume increased from 252 ± 100 cm(3) preoperatively to 300 ± 111 cm(3) at 1 month (P < 0.001). Liver and splenic hypertrophy were significant after major hepatectomies (+100% and +26%, respectively; P < 0.001), but not after minor hepatectomies. Liver hypertrophy was inversely correlated to RLV/TLV (r = -0.687, P < 0.001). Splenic hypertrophy was not correlated to RLV/TLV. Liver and splenic hypertrophy were linearly correlated (r = 0.495, P < 0.001). Neoadjuvant chemotherapy (n = 37), preoperative portal vein embolization (n = 10) and postoperative complications (overall: n = 25; major: n = 10; infectious: n = 6) had no impact on hepatic or splenic hypertrophy.

CONCLUSIONS

Splenic hypertrophy occurred after major hepatectomy, but was not correlated to the extent of resection, by contrast with liver hypertrophy. Nevertheless, there was a linear correlation between splenic and liver hypertrophy. This correlation suggests the hypothesis of a splenic action of hepatic growth factors or a redistribution of the total reticuloendothelial system rather than an effect of reduction of the portal bed or hepatic outflow.

Electro-Acupuncture at ‘neiguan— (Pc6) Attenuates Liver Injury in Endotoxaemic Rats

Background

Intravenous injection of lipopolysaccharide (LPS) stimulates macrophages to release proinflammatory cytokines and nitric oxide (NO). This results in hypotension, vascular hyporeactivity and multiple organ failure (eg, liver injury) in rats. In rats with endotoxin shock, electro-acupuncture (EA) of ‘Neiguan’ (PC6) retrieved blood pressure and reduced plasma concentrations of NO. The authors evaluated whether EA at PC6 could alleviate the development of liver injury and dysfunction in endotoxic rats.

Methods

A total of 28 male adult Wistar rats were included in this study. Rats received intravenous LPS (10 mg/kg for 4 h) or saline for 4 h followed by EA at PC6 acupuncture point.

Results

Elevated biochemical parameters of liver injury and marked infiltration of neutrophils into liver tissues caused by LPS were significantly attenuated by EA. However, hypotension, tachycardia and raised production of plasma NO were not suppressed by EA at PC6.

Conclusions

These results indicate that EA at PC6 should be further investigated as a possible adjuvant therapy for endotoxin-induced liver dysfunction. Its mechanism of action needs further investigation.

Antioxidant treatment attenuates intestinal mucosal damage and gut barrier dysfunction after major hepatectomy. Study in a porcine model

BACKGROUND

This study aims to evaluate whether injury of gut mucosa in a porcine model of post-hepatectomy liver dysfunction can be prevented using antioxidant treatment with desferrioxamine.

METHODS

Post-hepatectomy liver failure was induced in pigs combining major (70%) liver resection and ischemia/reperfusion injury. An ischemic period of 150 minutes, was followed by reperfusion for 24 h. Animals were randomly divided into a control group (n = 6) and a desferrioxamine group (DFX, n = 6). DFX animals were treated with continuous IV infusion of desferrioxamine 100 mg/kg. Intestinal mucosal injury (IMI), bacterial and endotoxin translocation (BT) were evaluated in all animals. Intestinal mucosa was also evaluated for oxidative markers.

RESULTS

DFX animals had significantly lower IMI score (3.3 ± 1.2 vs. 1.8 ± 0.9, p < 0.05), decreased BT in the portal circulation at 0 and 12 h of reperfusion (p = 0.007 and p = 0.008, respectively), decreased portal endotoxin levels at 6 (p = 0.006) and 24 h (p = 0.004), decreased systemic endotoxin levels (p = 0.01) at 24 h compared to controls. Also, 24 h post-reperfusion mucosal malondialdehyde and protein carbonyls were decreased in DFX animals compared to controls (4.1 ± 1.2 vs. 2.5 ± 1.2, p = 0.05 and 0.5 ± 0.1 vs. 0.4 ± 0.1, p = 0.04 respectively).

CONCLUSION

Desferrioxamine seems to attenuate mucosal injury from post-hepatectomy liver dysfunction possibly through blockage of iron-catalyzed oxidative reactions.

Beneficial effects of hyperoncotic albumin on liver injury and survival in peritonitis-induced sepsis rats

Liver injury/dysfunction developing in patients with sepsis may lead to an increased risk of death. Small-volume resuscitation with hyperoncotic albumin (HA) has been proposed to restore physiologic hemodynamics in hemorrhagic and septic shock. We evaluated whether HA resuscitation could alleviate the development of liver injury/dysfunction in rats with polymicrobial sepsis induced by cecal ligation and puncture (CLP). The male Wistar rats received 0.9% saline or HA (25%, 3 mL/kg intravenously) at 3 h after CLP or sham operation. All hemodynamic and biochemical variables were measured during the 18-h observation. After 18 h of CLP, the septic rats developed circulatory failure (i.e., hypotension, tachycardia, and poor tissue perfusion), liver injury (examined by biochemical variables and histologic studies), and a higher mortality. Hyperoncotic albumin not only ameliorated the deterioration of hemodynamic changes but also attenuated neutrophil infiltration and cell death in the liver of septic animals. The septic rats treated with HA had a higher survival when compared with those with 0.9% saline treatment. Moreover, the increased plasma IL-1β, plasma IL-6, plasma nitrite/nitrate concentrations, liver iNOS expression, and liver superoxide levels in CLP rats were attenuated after administration of HA. Thus, HA may be regarded as a potential therapeutic agent in the early treatment of septic shock to prevent or reduce subsequent liver failure.

An insight into the possible protective effect of pyrrolidine dithiocarbamate against lipopolysaccharide-induced oxidative stress and acute hepatic injury in rats

Lipopolysaccharide (LPS) is a major cell wall molecule of Gram-negative bacteria known to stimulate the synthesis and secretion of several toxic metabolites, such as reactive oxygen species. In this study, the effect of pyrrolidine dithiocarbamate (PDTC), an antioxidant with nuclear factor-κB inhibitor activity, was evaluated in LPS-induced oxidative stress and acute hepatic injury in rats. Animals were pretreated for 3 consecutive days with PDTC (200 mg/kg/day, i.p.) or saline and animals were then challenged with LPS (6 mg/kg, i.p.) or saline. Six hours after LPS injection, animals were decapitated and blood and liver samples were collected to assess the chosen biochemical parameters. Saline-pretreated animals challenged with LPS revealed extensive liver damage, as evidenced by increases in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transferase (γ-GT). Also, LPS treatment resulted in significant increases in serum lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α) and nitrite levels. Furthermore, LPS challenge caused oxidative stress as indicated by an increase in hepatic lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) and a decrease in hepatic reduced glutathione concentration (GSH) as well as decreased activities of superoxide dismutase (SOD) and catalase in hepatic tissues. The administration of PDTC prior to LPS challenge resulted in improved liver functions as evidenced by the decline in serum AST, ALT, γ-GT levels and reduction in serum LDH, TNF-α and nitrite levels. Moreover, PDTC reduced the chosen lipid peroxidation marker, TBARS and increased GSH concentration, and SOD and catalase activities in hepatic tissues. These results indicate that PDTC may be a useful pharmacological agent in alleviating LPS-induced oxidative stress and acute hepatic injury.

Simvastatin attenuates hepatic sensitization to lipopolysaccharide after partial hepatectomy

BACKGROUND

Hepatic resection may be curative in patients with hepatobiliary malignancies but excessive loss of liver volume may cause hepatic dysfunction and increase susceptibility to subsequent postoperative infections and sepsis. Herein, we hypothesized that pretreatment with simvastatin may protect against lipopolysaccharide (LPS)-induced liver damage after partial hepatectomy.

MATERIALS AND METHODS

Male C57Bl/6 mice underwent 68% hepatectomy and exposed to LPS after 24h. Animals were pretreated with simvastatin (0.02 and 0.2mg/kg). Serum alanine aminotransferase (ALT) and tumor necrosis factor-alpha (TNF-alpha) as well as leukocyte infiltration and hepatocyte apoptosis were examined 6h after LPS challenge. An in vitro endothelial cell adhesion assay was used to study the mechanisms of simvastatin on leukocyte adhesion and the role of P-selectin and lymphocyte function antigen-1 (LFA-1).

RESULTS

Partial hepatectomy increased the sensitivity of the remnant liver tissue to LPS-provoked tissue injury. Simvastatin pretreatment reduced the LPS-induced increase in serum levels of ALT by 65% in hepatectomized animals. Moreover, simvastatin decreased leukocyte infiltration and hepatocyte apoptosis in the liver remnant of endotoxemic mice. LPS-provoked serum levels of TNF-alpha were decreased by 83% in hepatectomized animals treated with simvastatin. TNF-alpha-induced leukocyte adhesion as well as P-selectin expression in endothelial cells and LFA-1 function were inhibited by simvastatin in vitro.

CONCLUSIONS

These novels findings demonstrate that simvastatin protects the remnant liver against endotoxemic injury following major hepatectomy. Thus, simvastatin reduced LPS-induced leukocyte recruitment and hepatocyte apoptosis in the liver remnant. One key mechanism appears to be related to the inhibition of TNF-alpha formation and function (P-selectin expression) as well as to direct actions on LFA-1 function. Thus, simvastatin may represent a novel therapeutic approach to prevent septic liver damage after partial liver resection.

Does the use of probiotics/synbiotics prevent postoperative infections in patients undergoing abdominal surgery? A meta-analysis of randomized controlled trials

BACKGROUND

Advances in surgery have considerably lowered postoperative morbidity. However, infection remains a considerable morbidity factor. The aim of this review is to identify the potential benefit(s) of the perioperative administration of probiotics/synbiotics to patients undergoing abdominal surgery.

METHODS

We searched PubMed, Scopus, Web of Science, and Cochrane library to identify randomized controlled trials (RCTs) that studied the perioperative administration of probiotics/synbiotics to patients undergoing abdominal surgery.

RESULTS

Nine RCTs studying 733 patients were included in our review. The incidence of postoperative pneumonia, cholangitis, and any infections as well as the duration of postoperative hospital stay and length of antibiotic therapy were lower among patients receiving probiotics than in the control group [six RCTs, 355 patients, odds ratio (OR) 0.24, 95% confidence interval (CI) 0.09-0.68; three RCTs, 209 patients, OR 0.18, 95% CI 0.05-0.57; seven RCTs, 514 patients, OR 0.26, 95% CI 0.12-0.55; five RCTs, 313 patients, OR -2.70, 95% CI -5.15 to -0.25; four RCTs, 250 patients, OR -4.01, 95% CI -5.11 to -2.92, respectively], while the incidence of postoperative wound infection, urinary tract infection, intra-abdominal abscess, and mortality was not different between patients of the compared groups (six RCTs, 355 patients, OR 0.52, 95% CI 0.23-1.18; five RCTs, 313 patients, OR 0.44, 95% CI 0.04-5.54; four RCTs, 226 patients, OR 0.44, 95% CI 0.12-1.59; nine RCTs, 685 patients, OR 0.98, 95% CI 0.29-3.29, respectively).

CONCLUSION

The use of probiotics/synbiotics may reduce postoperative infections after abdominal surgery. This is a promising infection-preventive measure that may decrease morbidity, length of antibiotic therapy, duration of hospital stay, and pressure for emergence of antimicrobial resistance. However, the results of this meta-analysis should be interpreted with caution due to the significant heterogeneity of the studies included.

Geranylgeranylacetone prevents acute liver damage after massive hepatectomy in rats through suppression of a CXC chemokine GRO1 and induction of heat shock proteins

BACKGROUND AND METHODS

Acute liver failure after massive hepatectomy remains a challenging problem. In this study, using a microarray designed to monitor the side effects of drugs, we examined changes in gene expression in the remnant liver during the 24 h after hepatectomy and the effects of a nontoxic heat shock protein (HSP) 70 inducer, geranylgeranylacetone (GGA), after 90% hepatectomy in rats.

RESULTS

A single oral administration of 100 mg/kg GGA significantly suppressed the release of aminotransferases and improved survival compared with vehicle administration. The hepatectomy upregulated 74 genes and downregulated 95. Interestingly, ten cytokine genes were upregulated, while no cytokine-related gene was downregulated. Among the ten cytokine genes, a potent chemoattractant for neutrophils, GRO1, was most rapidly and markedly upregulated after 90% hepatectomy. GGA effectively suppressed the up-regulation of GRO1 messenger ribonucleic acid, and this was validated by Northern hybridization. Microarray and immunoblot analyses showed that, in addition to HSP70 and HSP27, GGA preferentially induced an endoplasmic reticulum chaperone, BIP.

CONCLUSION

Considering hemodynamic and metabolic overloading as a primary cause of acute lever failure, the ER stress response enhanced by GGA may also play an important role in the prevention of overload-induced liver damage.

Differential regulation of protein S expression in hepatocytes and sinusoidal endothelial cells in rats with cirrhosis

BACKGROUND

Liver dysfunction caused by intrasinusoidal microthrombi is frequently observed in patients with cirrhosis after hepatectomy, but the mechanistic pathway remains unknown.

OBJECTIVE

In the present study, we evaluated the expression of protein S (PS) in hepatocytes and sinusoidal endothelial cells (SECs) from rats with dimethylnitrosoamine-induced cirrhosis before and after hepatectomy.

RESULTS

The plasma level of PS antigen was significantly decreased in cirrhotic rats as compared to control rats treated with vehicle. PS expression was significantly decreased in hepatocytes isolated from cirrhotic rats as compared to controls. In contrast, PS expression was significantly increased in SECs isolated from rats with cirrhosis as compared to controls. Interleukin-6 (IL-6) upregulated the expression of PS in hepatocytes, and tumor necrosis factor-alpha (TNF-alpha) decreased its expression in SECs from both cirrhotic and normal rats. The production of IL-6 and TNF-alpha by Kupffer cells and SECs was decreased in rats with cirrhosis as compared to controls. After hepatectomy, microthrombus formation was markedly enhanced in sinusoids from rats with cirrhosis, and the plasma levels of IL-6 and TNF-alpha were significantly increased in rats with cirrhosis as compared to controls. Furthermore, PS production in SECs was decreased, whereas that in hepatocytes was significantly increased in cirrhotic rats as compared to controls.

CONCLUSIONS

These findings suggest that PS expression is differently regulated in hepatocytes and SECs of rats with cirrhosis before and after hepatectomy, that the expression of PS is regulated by locally released inflammatory cytokines, and that decreased expression of PS in SECs may cause liver microthrombus formation, which is frequently observed in patients with cirrhosis after hepatectomy.

The adaptive response of the reticuloendothelial system to major liver resection in humans

OBJECTIVE

To evaluate the contribution of the liver to total circulatory reticuloendothelial system (RES) phagocytosis capacity in patients undergoing liver resection and to compare it with values in end-stage chronic liver disease.

SUMMARY BACKGROUND DATA

The mechanism whereby major liver resection is associated with a high incidence of infection is unknown. Significant impairment of RES phagocytosis has been described in liver failure, rendering such patients susceptible to infection; and we hypothesized that similar impairment might occur following major liver resection.

METHODS

A prospective study was conducted in which Tc-albumin microspheres blood clearance served as a parameter for RES phagocytosis and was studied together with indocyanine green blood clearance, actual liver volume measured by three-dimensional image analysis, and a clinical score of hepatic dysfunction in 17 patients undergoing liver resection and in 8 patients with end-stage chronic liver disease assessed for liver transplantation.

RESULTS

When expressed relative to volume unit of residual liver, microspheres clearance increased significantly in the immediate postoperative period (day 1) following major (0.009% versus 0.022% min(-1) mL(-1), P < 0.001), but not minor liver resection. In contrast, the absolute rate of microsphere clearance decreased following major resection (15% min(-1) versus 10% min(-1), P < 0.001) and was comparable with the rate observed in end-stage chronic liver disease (9% min(-1)). This decrease in circulatory microspheres clearance after resection paralleled a decrease in indocyanine green clearance (R2 = 0.511, P = 0.006), and there was a trend for those with moderate liver dysfunction to have lower microspheres clearance rates (P = 0.068).

CONCLUSION

Preservation of a minimum volume of functioning liver is a prerequisite for adequate RES phagocytosis capacity, and failure of this system may predispose patients undergoing major liver resection to infection as observed in clinical studies.

Liver failure following partial hepatectomy

While major liver resections have become increasingly safe due to better understanding of anatomy and refinement of operative techniques, liver failure following partial hepatectomy still occurs from time to time and remains incompletely understood. Observationally, certain high-risk circumstances exist, namely, massive resection with small liver remnants, preexisting liver disease, and advancing age, where liver failure is more likely to happen. Upon review of available clinical and experimental studies, an interplay of factors such as impaired regeneration, oxidative stress, preferential triggering of apoptotic pathways, decreased oxygen availability, heightened energy-dependent metabolic demands, and energy-consuming inflammatory stimuli work to produce failing hepatocellular functions.

Detection of microbial DNA in the blood of surgical patients for diagnosing bacterial translocation

Bacterial translocation sometimes occurs in patients during surgical stress and is associated with an increased incidence of septic morbidity. However, no reliable method has been established for diagnosing bacterial translocation in humans. Identification of minute quantities of microbial-specific DNA has been made possible using polymerase chain reaction (PCR) techniques. The aims of this study were to determine the prevalence of bacterial translocation in patients with surgical stress using PCR techniques and to evaluate the usefulness of blood PCR techniques for diagnosing bacterial translocation. DNA was extracted from the blood of 52 surgical patients (24 elective major surgery patients and 28 septic patients) and 10 healthy controls. PCR techniques were used to amplify genes from Escherichia coli, Bacteroides fragilis, a region of 16S ribosomal RNA found in many gram-positive and gram-negative bacteria, and Candida albicans. Bacterial and Candida albicans DNA were not detected in healthy volunteers. Enteric bacterial DNA was detected in patients with hepatic lobectomy, and Candida albicans DNA was detected in patients with esophagectomy on the first postoperative day. Enteric bacterial and Candida albicans DNA were detected in septic patients with findings diagnostic of bacterial translocation, such as small bowel obstruction, ulcerative colitis, or supramesenteric arterial occlusion or in those who had undergone chemotherapy for advanced colon cancer. However, none of the patients were positive by the blood culture technique. The PCR method is more sensitive than blood cultures for detecting bacterial components in the blood of septic patients and is a valuable tool for verifying bacterial translocation in patients who have undergone hepatic lobectomy or esophagectomy. It is also valuable in septic patients who do not have a defined focus of infection.

N-acetylcysteine attenuates bacterial translocation after partial hepatectomy in rats

BACKGROUND

Translocating enteric bacteria have been suggested as playing a major role in the development of infections after partial hepatectomy. We investigated the effect of N-acetylcysteine (NAC) on bacterial translocation (BT) and intestinal mucosa as the first line of defense against BT.

MATERIALS AND METHODS

We compared four groups of eight Sprague-Dawley male rats each: sham, control (partially hepatectomized), partial hepatectomy plus preoperative single-dose NAC, and a fourth that received partial hepatectomy with a preoperative single-dose NAC plus treatment with NAC for 2 days. Microorganism counts of tissues, lung injury score, lung tissue glutathione, and malondialdehyde levels and microscopy of intestinal mucosa were studied at the end of 48 h.

RESULTS

Microorganism count in the lung and mesenteric lymph node cultures and lung injury score were significantly higher in the control group when compared with the sham, third, and fourth groups (lung: 9919.6 versus 0.0, 2912.9, 1550.0 cfu/g tissue; mesenteric lymph nodes: 8458.3 versus 0.0, 89.0, 88.9 cfu/g tissue; lung injury score: 3.25 versus 0.5, 1.13, 1.75). In the control group, the villous height of the distal ileal mucosa was significantly shorter than the sham group (65.25 versus 75.25 microm) and the difference from groups 3 and 4 was not statistically significant. Neutrophil infiltration in the distal ileal mucosa of the control group was significantly higher than the sham, third and fourth groups (3.13 versus 0.25, 0.38 and 1.0).

CONCLUSIONS

The parenteral use of NAC attenuates bacterial translocation after partial hepatectomy in rats. Attenuation of the lung injury after partial hepatectomy in NAC-treated groups might be attributable to both anti-inflammatory effect and the effect on BT.

Synbiotics reduce postoperative infectious complications: a randomized controlled trial in biliary cancer patients undergoing hepatectomy

BACKGROUND AND AIMS

The clinical value of synbiotics in surgical patients remains unclear. The aim of this study was to investigate the effect of synbiotics on intestinal integrity and microflora, as well as on surgical outcome, in patients undergoing high-risk hepatectomy.

METHODS

Fifty-four patients with biliary cancer were randomly allocated to two groups before hepatectomy. One group received postoperative enteral feeding that included synbiotics; the other received enteral feeding only. Lactulose/mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, and fecal microflora and organic acid concentrations were determined. Postoperative infectious complications were recorded.

RESULTS

Of the 54 patients, 44 completed the trial (21 receiving synbiotics and 23 others as controls). Postoperative changes in L/M ratios and serum DAO activities were identical between the two groups. Numbers of beneficial bacteria increased in the synbiotics group after surgery but decreased in controls. Numbers of harmful microorganisms decreased in the synbiotics group but increased in controls. Total organic acid concentrations increased in the synbiotics group but decreased in controls. Incidence of infectious complications was 19% (4/21) in the synbiotics group and 52% (12/23) in controls (P<0.05). All study patients tolerated surgery (mortality 0%).

CONCLUSIONS

Synbiotics, combined with early enteral nutrition, can reduce postoperative infections. This beneficial effect presumably involves correction of an intestinal microbial imbalance induced by surgical stress.

Development and evaluation of an experimental model for investigating the pathogenesis and therapeutic strategies of acute liver failure

Because of the various etiologies of acute liver failure (ALF) a clinically relevant model must fulfill four criteria--reversibility, reproducibility, ALF-induced death, and a sufficient time interval for diagnosis and therapy between induction and death. In this study an experimental model was evaluated for these criteria. A total of 49 rats were randomized into seven groups: First, a pilot study was performed regarding the survival rate after different treatments: In group I, animals underwent a 70% liver resection. In group II, 70% liver resection was combined with ascending doses of postoperative endotoxin administration up to 400 microg/kg (group IIc). In group III, animals only underwent liver mobilization. In group IV, ALF was induced according to the protocol of group IIc, but with additional treatment of an endothelin-A-receptor (ETAR) antagonist. Animals in group V received only 400 microg endotoxin. After induction of ALF, all animals died within the first day, showing significantly elevated bilirubin and ammonium levels and severe damage to hepatocellular integrity. Application of the ETAR antagonist resulted in the survival of 6/7 animals until the 14th day; the biochemical and histomorphological changes were reversible. All other animals survived to the 14th day. A clinically relevant model of ALF in rats can be created by the combination of 70% liver resection and endotoxin application to produce an inflammatory component.

Changes in portal venous pressure in the early phase after living donor liver transplantation: pathogenesis and clinical implications

BACKGROUND

Although living-donor liver transplantation (LDLT) has been accepted for adult populations, the occurrence and pathogenesis of small-for-size syndrome remain highly controversial.

METHODS

Portal venous pressure (PVP) was measured in 79 cases of LDLT from anhepatic phase to day 14. PVP was monitored through a catheter inserted via the inferior mesenteric vein. In a separate series of seven cases of adult LDLT, the splenic artery was ligated following arterial reperfusion.

RESULTS

For days 2 to 4 and 9 to 11, recipients of small-for-size graft (<0.8% of body weight) displayed significantly higher PVP than recipients of larger grafts. The 13 patients with elevated mean PVP (>or=20 mm Hg) early in the first week (days 0-4) demonstrated significantly worse survival (84.5% vs. 38.5% at 6 months; P < 0.01), but this was not applicable to elevated mean PVP late in the first week (days 5-7). Elevated PVP early in the first week was also associated with higher incidence of bacteremia, cholestasis, prolonged prothrombin time, and ascites. Splenic artery ligation (SAL) immediately reduced PVP from 10 to 20 mm Hg (median, 16 mm Hg) to 9 to 13 mm Hg (median, 11 mm Hg; P = 0.02). Posttransplant PVP was significantly lower in SAL patients than in non-SAL patients from days 2 to 7 despite small graft size. Early PVP in SAL patients was consistently below 20 mm Hg, and survival was significantly better than in non-SAL patients with high early PVP (P < 0.01).

CONCLUSION

Elevated PVP in the early phase is strongly associated with poor patient survival attributable, at least in part, to small-for-size graft. Further elucidation of the pathogenesis behind this phenomenon and efforts to modify PVP will be key to improving results.

Liver in sepsis and systemic inflammatory response syndrome

In patients with sepsis and SIRS, the liver has two opposing roles: a source of inflammatory mediators and a target organ for the effects of the inflammatory mediators. The liver is pivotal in modulating the systemic response to severe infection, because it contains the largest mass of macrophages (Kupffer cells) in the body; these macrophages can clear the endotoxin and bacteria that initiate the systemic inflammatory response. This article summarizes the functional changes that take place in the liver during sepsis and systemic inflammatory response syndrome and discusses the cellular and molecular mechanisms that underlie clinical outcomes.

Hemodynamic interaction between portal vein and hepatic artery flow in small-for-size split liver transplantation

In split-liver transplantation, the entire portal flow is redirected through relatively small-for-size grafts. It has been postulated that excessive portal blood flow leads to graft injury. In order to elucidate the mechanisms of this injury, we studied the hemodynamic interactions between portal vein- and hepatic artery flow in an experimental model in pigs. Six whole pig liver grafts were implanted in Group 1 ( n=6) and six whole liver grafts were split into right and left grafts and transplanted to Groups 2 ( n=6) and 3 ( n=6), respectively. The graft-to-recipient liver volume ratio was 1:1, 2:3 and 1:3 in Groups 1, 2 and 3, respectively. Portal vein- and hepatic artery flows were measured with an ultrasonic flow meter at 60,120 and 180 min after graft reperfusion. Portal vein pressure was also recorded at the same time intervals. Graft function was assessed at 3,6h and 12h, and morphological changes at 12h after reperfusion. Following reperfusion, portal vein flow showed an inverse relationship to graft size, while hepatic artery flow was reduced proportionately to graft size. The difference was significant among the three groups ( P<0.05). Portal vein pressure was significantly higher in group 3, compared to groups 1 and 2 ( P<0.05). Hepatic artery buffer response was significantly higher in Group 3, compared to Groups 1 and 2 in relation to pre-occlusion values ( P<0.05). Split-liver transplantation, when resulting in small-for-size grafts, is associated with portal hypertension, diminished arterial flow, and graft dysfunction. Arterial flow impairment appears to be related to increased portal vein flow.

Geranylgeranylacetone suppresses inflammatory responses and improves survival after massive hepatectomy in rats

Overproduction of heat shock protein 70 (HSP70) in the liver protects hepatocytes under various pathologic conditions. In this study we examined the effects of a nontoxic HSP70 inducer, geranylgeranylacetone (GGA), on acute hepatic failure after 95% hepatectomy in rats. When GGA (100 mg/kg) or vehicle was intragastrically administered to rats 4 hours before 95% hepatectomy, all 25 rats pretreated with vehicle died within 60 hours after the operation, whereas 10 of 25 rats pretreated with GGA survived. During the 24-hour postoperative period, GGA significantly suppressed the release of aspartate or alanine aminotransferase and elevation of the serum interleukin-6 level, and completely inhibited an increase in the serum level of tumor necrosis factor-alpha. Histologic examinations showed that GGA prevented hemorrhagic necrosis, which was observed in vehicle-treated livers more than 12 hours after the operation. During the 24-hour postoperative period, HSP70 induction was absent in remnant livers of vehicle-treated rats. In contrast, GGA stimulated the HSP70 mRNA expression and HSP70 accumulation within 4 hours, and viable hepatocytes contained abundant HSP70 in their nuclei. Our results suggest that GGA may prevent acute liver failure after massive hepatectomy, at least in part, by enhancing HSP70 induction in the remnant liver.

Hepatic response to sepsis: interaction between coagulation and inflammatory processes

OBJECTIVES

a) To review the hepatic response to sepsis and to establish how this response contributes to coagulation and inflammatory processes; b) to review the physiologic and biochemical mechanisms that suggest hepatic dysfunction may occur during sepsis, enhance procoagulant and proinflammatory activities, and participate in the potential evolution to multiple organ dysfunction syndrome.

DATA SOURCES

A summary of published medical literature from MEDLINE search files and published reviews on liver function in experimental and human sepsis.

DATA SUMMARY

In sepsis, the liver plays a major role in host defense mechanisms. Kupffer cells are responsible for bacterial scavenging, bacterial products inactivation, and inflammatory mediators clearance and production. Hepatocytes, via receptors for many proinflammatory cytokines, modify their metabolic pathway toward gluconeogenesis, amino-acid uptake, and increased synthesis of coagulant and complement factors and protease inhibitors. The acute-phase protein (APP) response also contributes to the procoagulant state, especially by enhancing the inhibition of protein C (alpha1-antitrypsin and alpha2-macroglobulin) and by decreasing liver synthesis of protein C and antithrombin (negative APPs). Elevated C-reactive protein levels (positive APPs) promote the expression of tissue factor by mononuclear cells. Increased liver production of thrombin-activatable fibrinolytic inhibitor (positive APPs) enhances fibrinolysis inhibition. Conversely, such hepatic inflammatory and coagulation processes in sepsis may alter the function of this organ. Indeed, the liver can be injured by activated Kupffer cells that release chemokines, attract blood neutrophils into the liver, and activate them. Neutrophils up-regulate their surface adhesion molecules, tissue factor, and Kupffer cells, whereas tissue factor pathway inhibitor and thrombomodulin are almost undetectable in endothelial cells. This may lead to microcirculatory disturbances, fibrin deposition, hepatocyte injury, endotoxin and bacteria spillover, and multiple organ failure.

CONCLUSIONS

In sepsis, the liver participates in host defense and tissue repair through hepatic cell cross-talk that controls most of the coagulation and inflammatory processes. When this control is not adequate, a secondary hepatic dysfunction may occur and may sometimes lead to bacterial products spillover, enhanced procoagulant and inflammatory processes, and in turn, multiple organ failure and death.

Differential suppression of liver-specific genes in regenerating rat liver induced by extended hepatectomy

BACKGROUND/AIMS

The function of the remnant liver is critical to survival of patients following an extended hepatectomy. The aim of this study was to determine whether proliferating hepatocytes in the remnant liver preserve the expression of liver-specific genes.

METHODS

Using regenerating rat livers after 30, 70, and 90% partial hepatectomy (PHx), Northern blot analyses were performed with probes for seven liver-specific genes, six growth-related genes, two housekeeping genes and two acute phase reactant protein genes.

RESULTS

During the regeneration after 90% PHx, the transcription of liver-specific genes showed three chronological patterns: transcription of serum albumin and cytochrome P450 2B decreased rapidly and reached a nadir at 6 to 24 h after PHx; those of apolipoprotein A-1, phosphoenolpyruvate carboxykinase and ornithine transcarbamylase decreased gradually until 24 to 48 h; those of UDP-glucuronosyltransferase and hepatocyte nuclear factor 4 did not show any changes until 48 h after PHx. In contrast, expression levels of all the growth-related genes and of housekeeping genes increased rapidly after PHx. After 30 and 70% PHx, expression of these genes changed in a similar manner to the 90% PHx case but to a lower extent.

CONCLUSIONS

Based upon the fractions of Ki-67 positive hepatocytes in remnant livers, we could estimate the degree of expression of each liver-specific gene in the proliferating hepatocytes. The serum albumin gene was completely suppressed, while that encoding UDP-glucuronosyltransferase was not affected. These results correlated well with the patterns of albumin and bilirubin in rat serum after PHx. Other liver-specific genes were moderately suppressed in proliferating hepatocytes. Thus, expression of liver-specific gene is differentially suppressed when hepatocytes enter a proliferation cycle. Those that are unaffected may be indispensable for maintaining the homeostasis of the living organism.

Transplantation of highly differentiated immortalized human hepatocytes to treat acute liver failure

BACKGROUND

Temporary support of a damaged liver by a bioartificial liver (BAL) devise is a promising approach for the treatment of acute liver failure. Although human primary hepatocytes are an ideal source of hepatic function in BAL, shortage of human livers available for hepatocyte isolation is the limiting factor for the use of this modality. A clonal human hepatocyte cell line that can grow economically in culture and exhibit liver-specific functions should be an attractive solution to this problem.

METHODS

To test this alternative, primary human fetal hepatocytes were immortalized using Simian virus 40 large T antigen. To investigate the potential of the immortalized cells for BAL, we transplanted the cells into the spleen of adult rats and performed a 90% hepatectomy 12 hr later.

RESULTS

One of the cloned human liver cell lines, OUMS-29, showed highly differentiated liver functions. Intrasplenic transplanting of 20x10(6) OUMS-29 cells protected the animals from hyperammonemia and the associated hepatic encephalopathy. Survival was significantly prolonged in 90% of hepatectomized rats receiving OUMS-29 cells.

CONCLUSIONS

A highly differentiated immortalized human hepatocyte cell line, OUMS-29, was able to provide metabolic support during acute liver failure induced by 90% hepatectomy in rats. Essentially unlimited availability of OUMS-29 cells may be clinically useful for BAL treatment.

Does probiotics administration decrease serum endotoxin levels in infants?

PURPOSE

The aim of this study was to examine whether administration of probiotics to infants can change the ratio of intestinal flora and thereby decrease serum endotoxin produced by potentially pathogenic microorganisms.

METHODS

Nine infants including five with of biliary atresia, two with omphalocele, one each with Hirschsprung's disease and imperforate anus were studied. All patients were stable, and no antibiotics were given during this study. A probiotic mixture consisting of Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus was administered orally to each infant at 2 g/day for 2 weeks. Fecal aerobic and anaerobic bacterial cultures, serum endotoxin level, and other biochemical parameters were examined.

RESULTS

In fecal cultures, anaerobic bacteria including Bifidobacterium increased significantly whereas Escherichia coli, Streptococcus, and Klebsiella tended to decrease. The ratio of anaerobic to aerobic bacteria increased five times as a result of administration of probiotics, and serum endotoxin levels decreased.

CONCLUSIONS

Probiotics affect intestinal bacterial flora by increasing anaerobic bacteria and decreasing the population of potentially pathogenic microorganisms. A decrease in luminal endotoxin may result in less endotoxin translocation or bacterial translocation.

Effects of glutamine administration on liver regeneration following hepatectomy

The intestine is now known to be an important site of protein production in the body, and glutamine (GLN) stimulates both secreted and non-secreted protein synthesis in the small bowel. The purpose of the present study was to evaluate the effect of GLN-supplemented parenteral nutrition on liver regeneration after hepatectomy. Animals were divided into two groups: a sham-operated control group (Group A) and a 70%-hepatectomy group (Group B). Postoperatively, one-third of the animals in each group were maintained on intravenous 10% glucose solution, on 10% glucose with 2% standard amino acid solution, or 10% glucose supplemented with 2% glutamine for 24 h. GLN administration after hepatectomy significantly promoted liver regeneration. In addition, assessment of amino acid metabolism showed that GLN administration activated GLN metabolism in the intestine and promoted alanine uptake by the remnant liver. This metabolic response also enhanced both secreted and non-secreted protein synthesis in intestinal epithelial cells, especially in cells isolated from the crypts. The proteins produced are important as a portal production factor for liver regeneration and intestinal cell proliferation. Bacterial and endotoxin translocation, on the other hand, was significantly reduced. Thus, the results of this study suggest that intravenous administration of GLN after hepatectomy significantly promoted liver regeneration.

Pretreatment with IFN-gamma decreases infectious complications after partial hepatectomy in the rat

Infectious postoperative complications occur commonly after hepatectomy and may lead to a long hospital stay or death. The potential beneficial effects of interferon-gamma (IFN-gamma) in this setting were evaluated in a model of hepatectomy and sepsis in rodents. Incidence of bacterial translocation was measured in animals on days 1, 2, and 5 after partial hepatectomy. Macrophage function was quantified by in vitro tumoricidal activity and superoxide anion (O2-) production. Survival after partial hepatectomy and cecal ligation and puncture (CLP) was recorded. After partial hepatectomy, bacterial translocation was decreased on days 1 and 2 in animals pretreated with IFN-gamma (p < 0.05). Macrophages from animals treated with IFN-gamma had higher in vitro tumoricidal activity and production of O2- (p < 0.05). Hepatectomized animals pretreated with IFN-gamma had an increased survival after CLP (p < 0.05). IFN-gamma may be useful in decreasing the incidence of infectious complications after partial hepatectomy.

Progressive necrosis after hepatectomy and the pathophysiology of liver failure after massive resection

BACKGROUND

Mortality after hepatectomy in rats increases markedly beyond the classic 2/3 resection from which complete recovery is the rule. Because an extremely small hepatocyte population can theoretically sustain life, we hypothesize that lethal liver failure after subtotal resection could be due to progressive injury occurring in the remnant liver. The obligatory increase in portal blood through the small remnant may be central to the pathogenesis because of sinusoidal injury and Kupffer's cell activation. To test this hypothesis an experimental study in rats was undertaken to characterize liver cell injury after lethal (85%) and nonlethal (70%) hepatectomy.

METHODS

One hundred thirty Wistar rats were divided into three groups: control group (Sham laparotomy, n = 30), 70[5] hepatectomy group (n = 50), and 85% hepatectomy group (n = 50). Five rats in each group were killed for blood and liver collections from 15 minutes to day 14 after hepatectomy. Survival, histologic characteristics, serum activities of aspartate (AST) and alanine (ALT) aminotransferases and arginase were determined; serum level of tumor necrosis factor-alpha (TNF-alpha) and plasma level of prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assay.

RESULTS

Whatever the extent of resection, hepatic injury, as demonstrated by increased serum levels of arginase, ALT, and AST, was observed. The kinetics of arginase release after hepatectomy mimicked quite well those of AST and ALT, representing a reliable marker of hepatocyte injury. A significantly higher, more prolonged blood release of enzymes was observed after 85% hepatectomy than after 70% hepatectomy. Because of a very short half-life the rise in arginase several hours after hepatectomy seems to indicate ongoing liver damage distinct from the surgical injury. Significant elevations of TNF-alpha were detected that were much more severe after 85% hepatectomy. PGE2 levels that increased significantly after 70% resection remained depressed after 8% hepatectomy. Light microscopy demonstrated extensive patchy necrosis after 85% hepatectomy.

CONCLUSIONS

A pattern of progressive necrosis of the remnant liver was identified with Kupffer's cell dysfunction. We hypothesize that failure of down-regulation of TNF-alpha production by PGE2 could contribute to the pathophysiology of liver injury in the remnant after massive hepatectomy. These events may be initiated in part by the dramatic increase of portal flow through a too small remaining liver, and a pathologic mechanism may be amenable to pharmacologic manipulation.

Alterations in intestinal motility and microflora in experimental acute pancreatitis

CONCLUSION

A delay in intestinal transit time appears as an early event in acute pancreatitis, preceding intestinal bacterial overgrowth and translocation.

BACKGROUND

Septic complications, primarily caused by bacteria of enteric origin, are frequent in severe acute pancreatitis. Impairment in intestinal motility probably plays a pathophysiological role in the development of bacterial overgrowth and ensuing translocation.

METHODS

In the present study, the influence of acute pancreatitis on intestinal motility was evaluated by measuring small intestinal transit time in the rat. Acute pancreatitis was induced by the retrograde intraductal infusion of 0.2 mL taurodeoxycholate. Intestinal transit time was studied by intraduodenal injection of Krebs' phosphate-buffered solution labeled with Na2(51)CrCO4, and 1 h small intestinal transit was measured at 1, 3, 12, and 24 h, after induction of pancreatitis. Bacterial overgrowth was evaluated by measuring Escherichia coli counts in the colon and distal small intestine, and bacterial translocation to mesenteric lymph nodes, the liver, spleen, and pancreas was determined.

RESULTS

A delayed small intestinal transit time was noted from 3 h on after induction of acute pancreatitis, with most of the radioactivity retained in the first two intestinal segments. Overgrowth of E. coli was noted 12 h after induction of pancreatitis in both the colon and distal small intestine, and at the same time-point, a significant increase in the incidence of bacterial translocation to mesenteric lymph nodes was seen.

Carbon dioxide transport in rats with acute pancreatitis

CONCLUSION

The production, release, and transport of carbon dioxide from tissues to blood are facilitated both systemically and in the gastrointestinal tract in acute pancreatitis. Red blood cells are responsible for the major exchange and transport of this increase in CO2. The existence of arteriovenous shunting within the intestine is associated with tissue ischemia, which may be involved in the etiology of gut barrier failure in acute pancreatitis.

BACKGROUND

Hemodynamic alterations in acute pancreatitis have been described, while little is known about CO2 metabolism.

METHODS

Carbon dioxide metabolism was evaluated by virtual values of venoarterial CO2 concentration differences in the early phase after sham operation or induction of acute pancreatitis by intraductal injection of 5% sodium taurocholate in rats.

RESULTS

In acute pancreatitis, virtual values of the CO2 concentration increased in arterial RBC at 6 and 12 h as well as in caval and portal vein RBC and plasma. Virtual values of the dissolved CO2 concentration were reduced in arterial and portal vein blood. The increment in blood CO2 concentration related to the increase in CO2 tension from arterial to caval or portal vein valves at constant CO2 tension. The total increment in CO2 concentration from arterial to caval or portal vein blood increased. Whole body oxygen extraction increased, whereas gut oxygen extraction decreased in pancreatitis.

The role of oral administration of oatmeal fermented by Lactobacillus reuteri R2LC on bacterial translocation after acute liver failure induced by subtotal liver resection in the rat

BACKGROUND

Previous experimental studies showed that a disturbed ecology of the enteric bacterial population might contribute to the occurrence of bacterial translocation from the gut in acute liver failure (ALF).

METHODS

In the present study the effects of oral administration of exogenous Lactobacillus reuteri R2LC and oat fiber on bacterial overgrowth and translocation and on enterocyte protein contents were investigated in rats with ALF induced by subtotal liver resection. The oatmeal soup base was anaerobically inoculated with L. reuteri R2LC and fermented for 15 h. The animals were then fed with fermented or unfermented oatmeal or saline daily for 6 days before the experimental procedure.

RESULTS

The incidence of bacterial translocation to the systemic circulation was nil and 17% in rats subjected to sham operation with saline or 90% hepatectomy with fermented oatmeal, respectively, and 80-90% and 34-50% in rats subjected to hepatectomy with saline or unfermented oatmeal. One rat treated with fermented oatmeal had positive bacterial growth in mesenteric lymph nodes (MLN), which was significantly lower than in hepatectomized rats with saline or unfermented oatmeal (80-100% and 50-67%). No significant differences was demonstrable between hepatectomized animals with oral administration of fermented or unfermented oatmeal as compared with sham-operated rats. The number of anaerobic bacteria, Gram-negative anaerobes, and Lactobacillus decreased significantly, and the number of Escherichia coli increased in the distal small intestine and colon in hepatectomized animals with saline or unfermented oatmeal, as compared with animals subjected to sham operation or hepatectomy with fermented oatmeal.

CONCLUSIONS

The occurrence of bacterial translocation from the gut in 90% hepatectomy-induced ALF could be prevented by fermented oatmeal, which implies possibilities for biologically balancing the enteric bacterial ecology.