Role of serum markers for liver function and liver regeneration in the management of chloroform poisoning

Assessment of Liver Regeneration in Patients Who Have Undergone Living Donor Hepatectomy for Living Donor Liver Transplantation

BACKGROUND

Inflammation and the associated immune pathways are among the most important factors in liver regeneration after living donor hepatectomy. Various biomarkers, especially liver function tests, are used to show liver regeneration. The aim of this study was to evaluate the course of liver regeneration following donor hepatectomy (LDH) by routine and regeneration-related biomarkers.

METHOD

Data from 63 living liver donors (LLDs) who underwent LDH in Inonu University Liver Transplant Institute were prospectively analyzed. Serum samples were obtained on the preoperative day and postoperative days (POD) 1, 3, 5, 10, and 21. Regenerative markers including alfa-fetoprotein (AFP), des carboxy prothrombin (DCP), ornithine decarboxylase (ODC), retinol-binding protein 4 (RBP4), and angiotensin-converting enzyme isotype II (ACEII) and liver function tests including alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP) and total bilirubin levels were all analyzed.

RESULTS

The median age of the LLDs was 29.7 years and 28 LLDs were female. Eight LLDs developed postoperative complications requiring relaparotomy. The routine laboratory parameters including AST (<0.001), ALT (<0.001), ALP (<0.001), and total bilirubin (<0.001) showed a significant increase over time until postoperative day (POD) 3. For the regeneration-related parameters, except for the RBP4, all parameters including ACEII (p = 0.006), AFP (p = 0.002), DCP (p = 0.007), and ODC (p = 0.002) showed a significant increase in POD3. The regeneration parameters showed a different pattern of change. In right-lobe liver grafts, ACEII (p = 0.002), AFP (p = 0.035), and ODC (p = 0.001) showed a significant increase over time. DCP (p = 0.129) and RBP4 (p = 0.335) showed no significant changes in right-lobe liver grafts.

CONCLUSIONS

Regenerative markers are increased in a sustained fashion following LDH. This is more prominent following right-lobe grafts which are indicative of progenitor-associated liver regeneration.

Safety evaluation of fermented Platycodon grandiflorus (Jacq.) A.DC. extract: Genotoxicity, acute toxicity, and 13-week subchronic toxicity study in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Platycodon grandiflorus (Jacq.) A.DC. is a well-known traditional herbal medicine administered for bronchitis and inflammatory diseases. Especially, anti-inflammatory effect of fermented P. grandiflorus (Jacq.) A.DC. extract (FPGE) was higher than that of P. grandiflorus (Jacq.) A.DC. extract. However, toxicological information for FPGE is lacking.

AIM OF THE STUDY

In this study, we establish a toxicological profile for FPGE by testing genotoxicity, acute and 13-week subchronic toxicity.

MATERIALS AND METHODS

FPGE was evaluated with bacterial reverse mutation, chromosome aberration, and micronucleus test. For the acute- and 13-week subchronic toxicity tests, FPGE was administered orally at doses of 0, 750, 1500, and 3000 mg/kg in SD rats.

RESULTS

The results of the genotoxic assays indicated that FPGE induced neither mutagenicity nor clastogenicity. The acute toxicity test showed that FPGE did not affect animal mortality, clinical signs, body weight changes, or microscopic findings at ≤ 3000 mg/kg. The approximate lethal dose (ALD) of FPGE in SD rats was >3000 mg/kg. For the 13-week subchronic toxicity assay, no FPGE dose induced any significant change in mortality, clinical signs, body or organ weight, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination in either SD rat sex. The rat no observed adverse effects level (NOAEL) for FPGE was set to 3000 mg/kg.

CONCLUSIONS

The present study empirically demonstrated that FPGE has a safe preclinical profile and indicated that it could be safely integrated into health products for atopic dermatitis treatment.

Effect of human umbilical cord blood stem cell transplantation on oval cell response in 2-AAF/CCL4 liver injury model: experimental immunohistochemical study

Background

Oval cells, specific liver progenitors, are activated in response to injury. The human umbilical cord blood (hUCB) is a possible source of transplantable hepatic progenitors and can be used in cases of severe liver injury. We detected the effect of hUCB stem cell transplantation on natural response of oval cells to injury.

Methods

Twenty-four female albino rats were randomly divided into three groups: (A) control, (B) liver injury with hepatocyte block, and (C) hUCB transplanted group. Hepatocyte block was performed by administration of 2-acetylaminofluorene (2-AAF) for 12 days. CCL4 was administrated at day 5 from experiment start. Animals were sacrificed at 9 days post CCL4 administration, and samples were collected for biochemical and histopathological analysis. Oval cell response to injury was evaluated by the percentage of oval cells in the liver tissue and frequency of cells incorporated into new ducts.

Results

Immunohistochemical analysis of oval cell response to injury was performed. There was significant deviation in the hUCB-transplanted (4.9 ± 1.4) and liver injury groups (2.4 ± 0.9) as compared to control (0.89 ± 0.4) 9 days post injury. Detection of oval cell response was dependant on OV-6 immunoreactivity. For mere localization of cells with human origin, CD34 antihuman immunoreactivity was performed. There was no significant difference in endogenous OV-6 immunoreactivity following stem cell transplantation as compared to the liver injury group.

Conclusions

In vivo transplantation of cord blood stem cells (hUCB) does not interfere with natural oval cell response to liver injury.

Systemic inflammatory response due to chloroform intoxication--an uncommon complication

Well-known adverse effects of chloroform are drowsiness, nausea, and liver damage. Two cases with an uncommon complication due to chloroform intoxication are presented. In the first case, a general physician, because of nausea and dyspnea, admitted a 34-year-old woman to hospital. She developed a toxic pulmonary edema requiring mechanical ventilation for a few days, and a systemic inflammatory response syndrome (SIRS) with elevated white blood cell counts, a moderate increase of C-reactive protein, and slightly elevated procalcitonin levels. There were inflammatory altered skin areas progressing to necrosis later on. However, bacteria could be detected neither in blood culture nor in urine. Traces of chloroform were determined from a blood sample, which was taken 8 h after admission. Later, the husband confessed to the police having injected her chloroform and put a kerchief soaked with chloroform over her nose and mouth. In the second case, a 50-year-old man ingested chloroform in a suicidal attempt. He was found unconscious in his house and referred to a hospital. In the following days, he developed SIRS without growth of bacteria in multiple blood cultures. He died several days after admission due to multi-organ failure. SIRS in response to chloroform is a rare but severe complication clinically mimicking bacterial-induced sepsis. The mechanisms leading to systemic inflammation after chloroform intoxication are currently unclear. Possibly, chloroform and/or its derivates may interact with pattern recognition receptors and activate the same pro-inflammatory mediators (cytokines, interleukins, prostaglandins, leukotrienes) that cause SIRS in bacterial sepsis.

Lethal complications after poisoning with chloroform--case report and literature review

Chloroform is a potent central nervous system and respiratory depressant. The toxicities associated with chloroform frequently occur after inhalation. Hepatotoxicity is secondary to production of a toxic metabolite, with a peak elevation of liver enzymes 72 hours after exposure. Acute liver failure after chloroform inhalation is rarely described, this syndrome being produced mainly by viral hepatitis, idiosyncratic drug-induced liver injury, and acetaminophen ingestion. This report describes the case of a 46-year-old woman who presented to emergency department with coma, signs of respiratory failure, and solvent odor of her breath after chloroform inhalation and binge drinking. In evolution appeared lethal acute liver failure and rhabdomyolysis, despite maximum supportive care. Necroptic examination revealed microvesicular steatosis and tubular renal necrosis, specific for chloroform toxicity. This case illustrates the dramatic impact on liver of two well-recognized hepatotoxins. Mechanisms of chloroform and alcohol-induced liver toxicity are reviewed.

Beta-catenin activation promotes liver regeneration after acetaminophen-induced injury

Acute liver failure (ALF) remains a disease with poor patient outcome. Improved prognosis is associated with spontaneous liver regeneration, which supports the relevance of exploring 'regenerative' therapies. Therefore, the role of the Wnt/beta-catenin pathway in liver regeneration following ALF was investigated. ALF was induced in mice by acetaminophen overdose, which is also a leading cause of liver failure in patients. beta-catenin distribution was also studied in liver sections from acetaminophen-induced ALF patients. A nonlethal dose of acetaminophen, which induces liver regeneration, led to stabilization and activation of beta-catenin for 1 to 12 hours. These data were also verified by increased expression of the beta-catenin surrogate target glutamine synthetase. Beta-catenin activation occurred secondary to the inactivation of glycogen synthase kinase-3beta and an increase in levels of casein kinase 2alpha, and led to increased cyclin-D1, another known beta-catenin target. These observations were next substantiated in beta-catenin conditional-null mice (beta-catenin-null), which show dampened regeneration after acetaminophen injury following induction of CYP2e1/1a2 expression. In light of decreased acetaminophen injury in beta-catenin-null mice despite CYP induction, equitoxic studies in control mice were performed. Significant differences in regeneration persisted following comparable injury in beta-catenin-null and control animals. Retrospective analysis of liver samples from acetaminophen-overdose patients demonstrated a positive correlation between nuclear beta-catenin, proliferation, and spontaneous liver regeneration. Thus, our studies demonstrate early activation of beta-catenin signaling during acetaminophen-induced injury, which contributes to hepatic regeneration.

Mechanisms and outcomes of drug- and toxicant-induced liver toxicity in diabetes

Increase dincidences of hepatotoxicity have been observed in diabetic patients receiving drug therapies. Neither the mechanisms nor the predisposing factors underlying hepatotoxicity in diabetics are clearly understood. Animal studies designed to examine the mechanisms of diabetes-modulated hepatotoxicity have traditionally focused only on bioactivation/detoxification of drugs and toxicants. It is becoming clear that once injury is initiated, additional events determine the final outcome of liver injury. Foremost among them are two leading mechanisms: first, biochemical mechanisms that lead to progression or regression of injury; and second, whether or not timely and adequate liver tissue repair occurs to mitigate injury and restore liver function. The liver has a remarkable ability to repair and restore its structure and function after physical or chemical-induced damage. The dynamic interaction between biotransformation-based liver injury and compensatory tissue repair plays a pivotal role in determining the ultimate outcome of hepatotoxicity initiated by drugs or toxicants. In this review, mechanisms underlying altered hepatotoxicity in diabetes with emphasis on both altered bioactivation and liver tissue repair are discussed. Animal models of both marked sensitivity (diabetic rats) and equally marked protection (diabetic mice) from drug-induced hepatotoxicity are described. These examples represent a remarkable species difference. Availability of the rodent diabetic models offers a unique opportunity to uncover mechanisms of clinical interest in averting human diabetic sensitivity to drug-induced hepatotoxicities. While the rat diabetic models appear to be suitable, the diabetic mouse models might not be suitable in preclinical testing for potential hepatotoxic effects of drugs or toxicants, because regardless of type 1 or type2 diabetes, mice are resistant to acute drug-or toxicant-induced toxicities.

Dose-dependent liver regeneration in chloroform, trichloroethylene and allyl alcohol ternary mixture hepatotoxicity in rats

The present study was designed to examine the hypothesis that liver tissue repair induced after exposure to chloroform (CF) + trichloroethylene (TCE) + allyl alcohol (AA) ternary mixture (TM) is dose-dependent similar to that elicited by exposure to these compounds individually. Male Sprague Dawley (S-D) rats (250-300 g) were administered with fivefold dose range of CF (74-370 mg/kg, ip), and TCE (250-1250 mg/kg, ip) in corn oil and sevenfold dose range of AA (5-35 mg/kg, ip) in distilled water. Liver injury was assessed by plasma alanine amino transferase (ALT) activity and liver tissue repair was measured by (3) H-thymidine incorporation into hepatonuclear DNA. Blood and liver levels of parent compounds and two major metabolites of TCE [trichloroacetic acid (TCA) and trichloroethanol (TCOH)] were quantified by gas chromatography. Blood and liver CF and AA levels after TM were similar to CF alone or AA alone, respectively. However, the TCE levels in blood and liver were substantially decreased after TM in a dose-dependent fashion compared to TCE alone. Decreased plasma and liver TCE levels were consistent with decreased production of metabolites and elevated urinary excretion of TCE. The antagonistic interaction resulted in lower liver injury than the summation of injury caused by the individual components at all three-dose levels. On the other hand, tissue repair showed a dose-response leading to regression of injury. Although the liver injury was lower and progression was contained by timely tissue repair, 50% mortality occurred only with the high dose combination, which is several fold higher than environmental levels. The mortality could be due to the central nervous system toxicity. These findings suggest that exposure to TM results in lower initial liver injury owing to higher elimination of TCE, and the compensatory liver tissue repair stimulated in a dose-dependent manner mitigates progression of injury after exposure to TM.

Liver regeneration: a critical toxicodynamic response in predictive toxicology

The objective of the present review is to discuss the importance tissue repair in the mixture risk assessment. Studies have revealed the existence of two stages of toxicity: an inflictive stage (stage I) and progressive or regressive stage (stage II). While much is known about mechanisms by which injury is inflicted (stage I), very little is known about the mechanisms that lead to progression or regression of injury. A wide variety of additional experimental evidence suggests that tissue repair impacts decisively on the final toxic outcome and any modulation in this response has profound impact in the final outcome of toxicity. We designed the present research to investigate the importance of tissue repair in the final acute hepatotoxic outcome upon exposures to mixture of toxicants comprising thioacetamide (TA), allyl alcohol (AA), chloroform (CHCl(3)) and trichloroethylene (TCE). Dose response studies with individual compounds, binary mixtures (BM), ternary (TM) and quaternary mixtures (QM) have been conducted. Results of CHCl(3) + AA BM [Anand, S.S., Murthy, S.N., Vishal, V.S., Mumtaz, M.M., Mehendale, H.M., 2003. Tissue repair plays pivotal role in final outcome of supra-additive liver injury after chloroform and allyl alcohol binary mixture. Food Chem. Toxicol. 41, 1123] and CHCl(3) + AA + TA +TCE QM [Soni, M.G., Ramaiah, S.K., Mumtaz, M.M., Clewell, H., Mehendale, H.M., 1999. Toxicant-inflicted injury and stimulated tissue repair are opposing toxicodynamic forces in predictive toxicology. Regul. Phramcol. Toxicol. 19, 165], and two representative individual compounds (TA and AA) [Mangipudy, R.S., Chanda, S., Mehendale, H.M., 1995a. Tissue repair response as a function of dose in thioacetamide hepatotoxicity. Environ. Health Perspect. 103, 260; Soni, M.G., Ramaiah, S.K., Mumtaz, M.M., Clewell, H., Mehendale, H.M., 1999. Toxicant-inflicted injury and stimulated tissue repair are opposing toxicodynamic forces in predictive toxicology. Regul. Phramcol. Toxicol. 19, 165] are described in this review. In addition, modulation of tissue repair in the outcome of hepatotoxicity and its implications in the risk assessment have been discussed. Male Sprague-Dawley (S-D) rats (250-300g) received a single i.p. injection of individual toxicants as well as mixtures. Liver injury was assessed by plasma alanine amino transferase (ALT) and histopathology. Tissue regeneration response was measured by [(3)H]-thymidine ((3)H-T) incorporation into hepatocellular nuclear DNA and PCNA. Only ALT and (3)H-T data have been presented in this review for the sake of simplicity. Studies with individual hepatotoxicants showed a dose-related increase in injury as well as tissue repair up to a threshold dose. Beyond this threshold, tissue repair was inhibited, and liver injury progressed leading to mortality. Since the highest dose of individual compounds resulted in mortality, this dose was not employed for mixture studies. While CHCl(3) + AA BM caused supra-additive liver injury, QM caused additive liver injury. Due to the prompt and robust compensatory tissue repair, all the rats exposed to BM survived. With QM, the rats receiving the highest dose combination experienced some mortality consequent to the progression of liver injury attendant to suppressed tissue repair. These findings suggest that liver tissue repair, the opposing biological response that restores tissue lost to injury, may play a critical and determining role in the outcome of liver injury regardless of the number of toxicants in the mixture or the mechanism of initiation of injury. These data suggest that inclusion of this response in risk assessment might help in fine-tuning the prediction of toxic outcomes.

Tissue repair plays pivotal role in final outcome of liver injury following chloroform and allyl alcohol binary mixture

The objective of this study was to evaluate the interaction profile of chloroform (CHCl(3))+allyl alcohol (AA) binary mixture (BM)-induced acute hepatotoxic response. Plasma alanine aminotransferase (ALT) was measured to assess liver injury, and 3H-thymidine (3H-T) incorporation into hepatonuclear DNA was measured as an index of liver regeneration over a time course of 0-72 h. Male Sprague-Dawley (S-D) rats received single ip injection of 5-fold dose range of CHCl(3) (74, 185 and 370 mg/kg) in corn oil (maximum 0.5 ml/kg) and 7-fold dose range of AA (5, 20 and 35 mg/kg) in distilled water simultaneously. The doses for BM were selected from individual toxicity studies of CHCl(3) alone [Int. J. Toxicol. 22 (2003) 25], and AA alone [Reg. Pharmacol. Toxicol. 19 (1999) 165]. Since the highest dose of each treatment (CHCl(3)- 740 and AA- 50 mg/kg) yielded mortality due to the suppressed tissue repair followed by liver failure, this dose was omitted for BM. The levels of CHCl(3) (30-360 min) and AA (5-60 min) were quantified in blood and liver by gas chromatography (GC). The liver injury was more than additive after BM compared to CHCl(3) alone or AA alone at highest dose combination (370+35 mg/kg), which peaked at 24 h. The augmented liver injury observed with BM was consistent with the quantitation data. Though the liver injury was higher, the greater stimulation of tissue repair kept injury from progressing, and rescued the rats from hepatic failure and death. At lower dose combinations, the liver injury was no more than additive. Results of the present study suggest that liver tissue repair, in which liver tissue lost to injury is promptly replaced, plays a pivotal role in the final outcome of liver injury after exposure to BM of CHCl(3) and AA.

Role of Laboratory in the Management of Phenylbutazone Poisoning

We report a rare case of intentional overdose of phenylbutazone in a 15-yr-old female. The patient exhibited symptoms of phenylbutazone toxicity and the presence of the drug was confirmed by gas chromatography mass-spectrometry (GC-MS) analysis of the initial urine sample. The patient underwent plasmapheresis to remove the drug from the circulation. Semiquantitation of sequential serum samples by GC-MS revealed elimination of phenylbutazone by day 5 of admission at which time the plasmapheresis was discontinued. Elevated blood urea nitrogen (BUN) and creatinine returned to normal. Analysis of biomarkers for liver necrosis and regeneration in sequential serum samples revealed the restoration of normal liver function by day 5. This case further confirms our previous observations that biomarkers for liver necrosis and regeneration can predict the outcome of patients with liver damage due to toxins.

Extent and timeliness of tissue repair determines the dose-related hepatotoxicity of chloroform

As a part of mixture toxicity studies, the objective of the present investigation was to validate the hypothesis that the rate and extent of liver tissue repair response to a given dose determines the end result of toxicity (death or recovery), regardless of the mechanisms by which injury is inflicted, using a well-known environmental pollutant, chloroform (CHCl(3)). In future, the data will be used to compare with the results of mixtures containing CHCl(3) to aid in characterizing the safety of chemical mixtures and to construct a physiologically based pharmacokinetic (PBPK) model for dose, route, and species extrapolation. Hepatotoxicity and tissue repair were measured in male Sprague-Dawley rats (S-D) receiving a 10-fold dose range of CHCl(3) (74, 185, 370, and 740 mg/kg, IP) during a time course of 0 to 96 hours. Liver injury, as assessed by plasma alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) elevation, increased with dose over the 10-fold dose range. Because CHCl(3) is also known to cause kidney damage, blood urea nitrogen (BUN) and creatinine were measured to evaluate the kidney injury. With doses up to 370 mg/kg, liver injury increased in a dose-related fashion, which peaked at 24 hours and returned to normal after 48 hours, whereas at highest dose (740 mg/kg), the injury was progressive resulting in 90% mortality. Blood and liver CHCl(3) levels were quantified using gas chromatography (GC) over a time course of 30 to 360 minutes. The dose-related increase in the blood and liver CHCl(3) levels were consistent with dose-dependent liver injury. Tissue regeneration response, as measured by [(3)H]-thymidine incorporation into hepatocellular nuclear DNA peaked at 36 hours in rats treated with the lower two doses of CHCl(3) (74 and 185 mg/kg). Further increase in CHCl(3) dose to 370 mg/kg resulted in an earlier increase in [(3)H]-thymidine incorporation at 24 hours, which peaked at 36 hours. However, at the highest dose of CHCl(3) (740 mg/kg), tissue repair was delayed and attenuated, allowing for unrestrained progression of liver injury. The kidney injury markers after CHCl(3) administration were not different from controls. These results support the concept that in addition to the magnitude of tissue repair response, the time at which this response occurs is critical in restraining the progression of injury. Measuring tissue repair and injury as simultaneous biological responses to toxic agents might increase the usefulness of dose-response paradigms in predictive toxicology and risk assessment. Although the dosimetry of the present study was well beyond the environmental exposure levels of CHCl(3), a PBPK model will be developed in future based upon these data to evaluate the effects at environmental levels.

A toxicologist's guide to biomarkers of hepatic response

Biological markers (biomarkers) are used to recognize, characterize and monitor treatment-related responses following exposure to xenobiotics. Biomarkers serve three primary applications in toxicology: 1) to confirm exposure to a deleterious agent, 2) to provide a system for monitoring individual susceptibility to a toxicant, and 3) to quantitatively assess deleterious effects of a toxicant to an organism or individual. Because the liver is a general target for adverse effects of drugs and other chemicals, biomarkers of untoward hepatic response to xenobiotics are of particular interest to the pharmaceutical toxicologist. General requirements for the latter category of biomarkers are sample availability, target organ specificity, sensitivity for the toxicity of interest, accessibility, a relatively short half-life, and available detection systems. Biomarkers that can be assayed in biological fluids from both human and animal subjects are particularly desirable. Histologically, acute and subacute hepatic toxicity commonly involves necrosis, steatosis, cholestasis, vascular disorders, or multiple lesions. The purpose of this review is to summarize reported applications using clinical analytes and biochemical indicators of hepatic dysfunction with emphasis on those that show promise of supplementing or improving upon standard laboratory procedures. Liver function markers refer to peripheral indicators of hepatic synthetic and secretory activities, enterohepatic function, or perturbations of the hepatic uptake and clearance of circulating biomolecules. Liver injury biomarkers include various peripheral proteins released in response to a cellular damage or locally, proteins that are significantly altered within the liver. These include both circulating cytosolic, mitochondrial, or canalicular membrane markers, and the up-regulation or depletion of radical scavengers, modulators, and stabilizers of intracellular damage. Subsequent recovery from a toxic insult involves repair, regenerative, and proliferative responses that constitute the third class of biomarkers. Of these, protein markers found either in sera, plasma, or urine either during or just prior to the early manifestation of histological hepatic lesions are of greatest interest. Examples of a number of these markers, their documented applications in humans or animals, and potential advantages as well as limitations are presented.