Acetaminophen-induced Changes Research Articles

An Observationa Study on the Role of Zinc Sulphate in Paracetamol Toxicity

Aim: The aim of this study was to determine the role of Zinc Sulphate as an agent of hepatoprotective in the acetaminophen-induced changes of histopathological nature in the model of animals. Methodology: The design of this study was observational study design. This study was conducted at Allied Hospital Faisalabad and the duration of this study was from April 2022 to July 2022. Our research sample was 90 albino rats with the range of weight from 18 – 32 grams and we made three groups each group consisting of thirty albino rats. Control group was A group and normal saline level was maintained in this group as 0.9%; acetaminophen was given (250 mg / kg) in B group through a single dose; Zinc Sulphate (1 – 5 mg / kg) was given to C group for a duration of 1 – 7 days before the acetaminophen (250 mg / kg) Sigle dose. After the six hours’ duration was conducted biochemical studies after giving acetaminophen to albino rats. At last step of the treatment weight of all animals was checked at than sacrificed. Histopathological and gross examination was carried out for liver and statistical evaluation of the data was carried out through Chi-Square test. Results: Demonstration of the zinc’s protective effect was made through serum concentration reduction level of the enzymes of liver such as aspartate aminotransferase, lactate dehydrogenase, alanine aminotransferase and serum sorbitol dehydrogenase, including the histopathological centrilobular congestion changes, necrosis and hepatocellular degeneration. We observed through the histopathological evaluation that typical changes in pathological environment of centri-zonal necrosis, leukocyte infiltration, steatosis, edema in animals and portal tiraditos those were treated only with acetaminophen. Animal pretreatment through zinc sulphate lead the whole procedure to dependent on the dose for the avoidance of various changes. Practical Implication: In the practical implication of this study the determination of the Zinc Sulphate role as an agent of hepatoprotective in the acetaminophen-induced changes of histopathological nature in the model of animals. Conclusion: It is concluded that Zinc is responsible for the production of hepato-protective effect with the prevention of ultrastructural hepatic tissue injuries and also causes free amino acid metabolism disturbance which is a result of the acetaminophen toxic dose. Keywords: Acetaminophen, Zinc, Liver Toxicity And Hepato-Protective Effect.

Dynamic and accurate assessment of acetaminophen-induced hepatotoxicity by integrated photoacoustic imaging and mechanistic biomarkers in vivo

The prediction and understanding of acetaminophen (APAP)-induced liver injury (APAP-ILI) and the response to therapeutic interventions is complex. This is due in part to sensitivity and specificity limitations of currently used assessment techniques. Here we sought to determine the utility of integrating translational non-invasive photoacoustic imaging of liver function with mechanistic circulating biomarkers of hepatotoxicity with histological assessment to facilitate the more accurate and precise characterization of APAP-ILI and the efficacy of therapeutic intervention.Perturbation of liver function and cellular viability was assessed in C57BL/6J male mice by Indocyanine green (ICG) clearance (Multispectral Optoacoustic Tomography (MSOT)) and by measurement of mechanistic (miR-122, HMGB1) and established (ALT, bilirubin) circulating biomarkers in response to the acetaminophen and its treatment with acetylcysteine (NAC) in vivo. We utilised a 60% partial hepatectomy model as a situation of defined hepatic functional mass loss to compared acetaminophen-induced changes to.Integration of these mechanistic markers correlated with histological features of APAP hepatotoxicity in a time-dependent manner. They accurately reflected the onset and recovery from hepatotoxicity compared to traditional biomarkers and also reported the efficacy of NAC with high sensitivity. ICG clearance kinetics correlated with histological scores for acute liver damage for APAP (i.e. 3h timepoint; r=0.90, P<0.0001) and elevations in both of the mechanistic biomarkers, miR-122 (e.g. 6h timepoint; r=0.70, P=0.005) and HMGB1 (e.g. 6h timepoint; r=0.56, P=0.04).For the first time we report the utility of this non-invasive longitudinal imaging approach to provide direct visualisation of the liver function coupled with mechanistic biomarkers, in the same animal, allowing the investigation of the toxicological and pharmacological aspects of APAP-ILI and hepatic regeneration.

Acetaminophen-Induced Changes in Systemic Blood Pressure in Critically Ill Patients: Results of a Multicenter Cohort Study.

We sought to assess the incidence of acetaminophen-induced hypotension. Our secondary objectives were to describe systemic hemodynamic changes and factors associated with this complication. Prospective observational study. Three ICUs. Adult patients requiring IV acetaminophen infusion. Arterial pressure was monitored via an arterial catheter for 3 hours. Hypotension was defined as a decrease in the mean arterial pressure of greater than or equal to 15% compared with the baseline. Overall, 160 patients were included in this study. Eighty-three patients (51.9%) experienced acetaminophen-induced hypotension according to our definition. In patients with acetaminophen-induced hypotension, the nadir mean arterial pressure was 64 mm Hg (95% CI, 54-74). Hypotension was observed 30 minutes (95% CI, 15-71) after acetaminophen infusion. Changes in mean arterial pressure were closely correlated with decreases in the diastolic arterial pressure (r = 0.92) and to a lesser extent with changes in the pulse pressure (r = 0.18) and heart rate (r = 0.09). Changes in the body temperature were not correlated with changes in mean arterial pressure (r = 0.0002; p = 0.85). None of the patients' baseline characteristics (shock, use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, lactates, renal replacement therapy, chronic heart disease, and indication for acetaminophen infusion) or clinically relevant characteristics (baseline severity according to Logistic Organ Dysfunction score, need for vasopressors, use of antihypertensive agents, need for mechanical ventilation, or changes in the body temperature) were independently associated with acetaminophen-induced hypotension. Among patients with acetaminophen-induced hypotension, 29 (34.9%) required therapeutic intervention. Half of the patients who received IV injections of acetaminophen developed hypotension, and up to one third of the observed episodes necessitated therapeutic intervention. Adequately powered randomized studies are needed to confirm our findings, provide an accurate estimation of the consequences of acetaminophen-induced hypotension, and assess the pathophysiologic mechanisms involved.

Oral thearubigins do not protect against acetaminopheninduced hepatotoxicity in mice

Purpose: To investigate the potential protective effect of oral repeated doses of thearubigins against acetaminophen-induced hepatotoxicity in mice.Methods: Mice were randomly divided into six groups (n=8) and administered the following: Control group (saline), acetaminophen group (saline), N-acetylcysteine group (500 mg/kg/day), and thearubigins groups (60, 70, 100 mg/kg/day). The drugs were given orally by gavage for seven days. On day 7, 1 h after the last dose of treatment, the mice (except control group) were given a single dose of acetaminophen (n-acetyl-p-aminophenol, APAP) orally by gavage (350 mg/kg) and then sacrificed 4 h post-APAP intake. Blood was collected for biochemical measurements and their liver were subjected to biochemical and histopathological assessment.Results: The acetaminophen group showed significant increases (p &lt; 0.001) in serum alanine aminotransferase level, hepatic cytochrome P2E1 level, and serum and hepatic malondialdehyde levels. Moreover it showed significant decrease (p &lt; 0.001) in serum and hepatic glutathione levels. Morphologically, the liver sections showed cellular necrosis, vacuolization, and degeneration around the centrilobular veins. Pretreatment with N-acetylcysteine reversed all acetaminophen-induced changes (p &lt; 0.001 for all biomarkers except for hepatic MDA (p = 0.014) while pretreatment with thearubigins failed to reverse any of them.Conclusion: Oral repeated doses of thearubigins failed to protect against acetaminophen-induced hepatotoxicity in mice and didn't affect hepatic cytochrome P2E1 level.Keywords: Acetaminophen, Hepatotoxicity, Thearubigins, N-acetylcysteine, Cellular necrosis, Vacuolization, Hepatic cytochrome P2E1

Role of nicotinamide (vitamin B3) in acetaminophen-induced changes in rat liver: Nicotinamide effect in acetaminophen-damged liver

Acetaminophen is a widely used analgesic and antipyretic agent, which is safe at therapeutic doses. However, overdoses of acetaminophen induce severe oxidative stress, which leads to acute liver failure. Nicotinamide has proven effective in ameliorating many pathological conditions that occur due to oxidative stress. This study verifies the prophylactic and therapeutic effects of nicotinamide against the hepatic pathophysiological and ultrastructural alterations induced by acetaminophen. Wistar rats intoxicated with an acute overdose of acetaminophen (5g/kg b.wt) were given a single dose of nicotinamide (500mg/kg b.wt) either before or after intoxication. Acetaminophen caused significant elevation in the liver functions and lipid peroxidation marker, and decline in the activities of the hepatic antioxidant enzymes. This oxidative injury was associated with hepatic centrilobular necrosis, hemorrage, vacuolar degeneration, lipid accumulation and mitochondrial alterations. Treating intoxicated rats with nicotinamide (500mg/kg) significantly ameliorated acetaminophen-induced biochemical changes and pathological injuries. However, administering the same dose of nicotinamide to healthy animals or prior to acetaminophen-intoxication induced hepatotoxicity. Caution should be taken when administering high doses of NAM because of its possible hepatotoxicity. Considering the wide use of nicotinamide, there is an important need for monitoring nicotinamide tolerance, safety and efficacy in healthy and diseased subjects.

Susceptibility of rat non‐alcoholic fatty liver to the acute toxic effect of acetaminophen

Acetaminophen overdose is the most frequent cause of acute liver failure. Non-alcoholic fatty liver disease is the most common chronic condition of the liver. The aim was to assess whether non-alcoholic steatosis sensitizes rat liver to acute toxic effect of acetaminophen. Male Sprague-Dawley rats were fed a standard diet (ST-1, 10% kcal fat) and high-fat gelled diet (HFGD, 71% kcal fat) for 6 weeks and then acetaminophen was applied in a single dose (1 g/kg body weight). Animals were killed 24, 48 and 72 h after acetaminophen administration. Serum biochemistry, activities of mitochondrial complexes, hepatic malondialdehyde, reduced and oxidized glutathione, triacylglycerol and cholesterol contents, and concentrations of serum and liver cytokines (TNF-α, TGF-β1) were measured and histopathological samples were prepared. The degree of liver inflammation and hepatocellular necrosis were significantly higher in HFGD fed animals after acetaminophen administration. Serum markers of liver injury were elevated only in acetaminophen treated HFGD fed animals. Concentration of hepatic reduced glutathione and ratio of reduced/oxidized glutathione were decreased in both ST-1 and HFGD groups at 24 h after acetaminophen application. Mild oxidative stress induced by acetaminophen was confirmed by measurement of malondialdehyde. Liver content of TNF-α was not significantly altered, but hepatic TGF-β1 was elevated in acetaminophen treated HFGD rats. We did not observe acetaminophen-induced changes in activities of respiratory complexes I, II, and IV and activity of caspase-3. Liver from rats fed HFGD is more susceptible to acute toxic effect of acetaminophen, compared to non-steatotic liver.

Proteomic Analysis of Acetaminophen-Induced Changes in Mitochondrial Protein Expression Using Spectral Counting

Comparative proteomic analysis following treatment with acetaminophen (APAP) was performed on two different models of APAP-mediated hepatocellular injury in order to both identify common targets for adduct formation and track drug-induced changes in protein expression. Male C57BL/6 mice were used as a model for APAP-mediated liver injury in vivo, and TAMH cells were used as a model for APAP-mediated cytotoxicity in vitro. SEQUEST was unable to identify the precise location of sites of adduction following treatment with APAP in either system. However, semiquantitative analysis of the proteomic data sets using spectral counting revealed a downregulation of P450 isoforms associated with APAP bioactivation and an upregulation of proteins related to the electron transport chain by APAP compared to the control. Both mechanisms are likely compensatory in nature as decreased P450 expression is likely to attenuate toxicity associated with N-acetyl-p-quinoneimine (NAPQI) formation, whereas APAP-induced electron transport chain component upregulation may be an attempt to promote cellular bioenergetics.

Potential role of caveolin-1 in acetaminophen-induced hepatotoxicity

Caveolin-1 (Cav-1) is a membrane scaffolding protein, which functions to regulate intracellular compartmentalization of various signaling molecules. In the present studies, transgenic mice with a targeted disruption of the Cav-1 gene (Cav-1 −/−) were used to assess the role of Cav-1 in acetaminophen-induced hepatotoxicity. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis and increases in serum transaminases. This was correlated with decreased expression of Cav-1 in the liver. Acetaminophen-induced hepatotoxicity was significantly attenuated in Cav-1 −/− mice, an effect that was independent of acetaminophen metabolism. Acetaminophen administration resulted in increased hepatic expression of the oxidative stress marker, lipocalin 24p3, as well as hemeoxygenase-1, but decreased glutathione and superoxide dismutase-1; no differences were noted between the genotypes suggesting that reduced toxicity in Cav-1 −/− mice is not due to alterations in antioxidant defense. In wild-type mice, acetaminophen increased mRNA expression of the pro-inflammatory cytokines, interleukin-1β, and monocyte chemoattractant protein-1 (MCP-1), as well as cyclooxygenase-2, while 15-lipoxygenase (15-LOX), which generates anti-inflammatory lipoxins, decreased. Acetaminophen-induced changes in MCP-1 and 15-LOX expression were greater in Cav-1 −/− mice. Although expression of tumor necrosis factor-α, a potent hepatocyte mitogen, was up-regulated in the liver of Cav-1 −/− mice after acetaminophen, expression of proliferating cell nuclear antigen and survivin, markers of cellular proliferation, were delayed, which may reflect the reduced need for tissue repair. Taken together, these data demonstrate that Cav-1 plays a role in promoting inflammation and toxicity during the pathogenesis of acetaminophen-induced injury.

The Concentration and Temporal Relationships of Acetaminophen-Induced Changes in Intracellular and Extracellular Total Glutathione in Freshly Isolated Hepatocytes from Untreated and 3-Methylcholanthrene Pretreated Sprague-Dawley and Fischer Rats

Fischer rats are more sensitive to acetaminophen-induced hepatotoxicity than Sprague-Dawley rats, however, the mechanisms for this enhanced sensitivity remain unclear. The susceptibility to hepatotoxicity is determined largely by the balance between acetaminophen toxification and detoxification. Since glutathione plays a critical role in the detoxification process, it would be of interest to compare the effects of acetaminophen on hepatic glutathione homeostasis in the Sprague-Dawley and Fischer rat, and relate these effects to cytotoxicity. To this end, we measured the sequential changes of intracellular and extracellular total glutathione in freshly isolated hepatocytes from untreated and 3-methylcholanthrene pretreated Fischer and Sprague-Dawley rats, both in the absence (basal) and presence of acetaminophen. In the basal state, the intracellular total glutathione content was significantly (P less than 0.01) increased in hepatocytes from untreated Fischer rats. Nevertheless, the sequential release of total glutathione into the medium and the sequential depletion of intracellular total glutathione were quantitatively similar in hepatocytes from untreated Fischer and Sprague-Dawley rats. Following exposure to acetaminophen, there was a striking dose and time associated depletion of intracellular total glutathione in untreated hepatocytes from both rat strains, and quantitatively the depletion was similar in untreated hepatocytes from both rat strains. This degree of depletion of intracellular total glutathione was not associated with acetaminophen-induced cytotoxicity in Sprague-Dawley hepatocytes, whereas significant (P less than 0.05) cytotoxicity was demonstrated in Fischer hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural effects of acetaminophen in isolated mouse hepatocytes

The ultrastructure of isolated mouse hepatocytes shows good correlation with that of cells from intact liver. Incubation of isolated mouse hepatocytes with 1.0 m M acetaminophen causes a variety of cytoplasmic and cell surface lesions, as well as cell death. The changes are similar or equivalent to those caused by acetaminophen in vivo. The most prominent feature of damage in isolated hepatocytes is bled formation, which is also seen occasionally in control incubations. The protective compound α-mercaptopropionylglycine and the antidote N-acetylcysteine both prevented the acetaminophen-induced changes. It is suggested that the in vivo counterpart to the blebs are endocytic vacuoles which form at cell margins due to the intravascular pressure of the sinusoids. It is suggested that the cell surface changes both in vivo and in isolated hepatocytes are caused by some dysfunction to the microfilament component of the cytoskeleton.