Pulmonary fat embolism induced by exposure to high ambient temperature in rats with a fatty liver

Molecular-biological analysis of acute lung injury (ALI) induced by heat exposure and/or intravenous administration of oleic acid

The aim of this study was to molecular-biologically investigate the interaction between heat exposure and pulmonary fat embolization in regards to the development of acute lung injury (ALI). Ten-week-old Wistar male rats were divided into four groups: (1) oleic acid injected into caudal vein after heat exposure, (2) oleic acid injected without heat exposure, (3) soybean oil injected after heat exposure, and (4) soybean oil injected without heat exposure, and then mRNA expression of eight inflammatory mediators related to ALI/acute respiratory distress syndrome (ARDS) and heat shock protein 70 (Hsp70) in lung was determined 1h after the injection. mRNA expression of interleukin 1 beta (Il1b), tumor necrosis factor alpha (Tnfa), vascular endothelial growth factor A (Vegfa), transforming growth factor beta 1 (Tgfb1) and Hsp70 was significantly increased by heat exposure, while that of Il1b, interleukin 6 (Il6), Tnfa, macrophage inflammatory protein 2 (Mip2) and granulocyte macrophage-colony stimulating factor (Gm-csf) was significantly elevated by the injection of oleic acid. Moreover, the expressions of inflammatory cytokines and chemokines in lung almost paralleled their mRNA expressions. In particular, IL-1β expression was synergistically elevated by heat exposure followed by injection of oleic acid. Additionally, IL-6 expression tended to increase under the same conditions as well. It is likely that heat exposure itself injures lung tissue within a short time, and that more than two conditions which induce ALI/ARDS interact with each other synergistically, exacerbating the development of ALI/ARDS.

The blood concentration and organ distribution of haloperidol at therapeutic and toxic doses in severe fatty liver disease

The aim of this study was to investigate the difference between the pharmacokinetics of haloperidol in normal rats and in rats with fatty liver disease. A therapeutic dosage (0.1 mg/kg) and a toxic dose (15 mg/kg) of haloperidol were administrated to normal 9-week-old male rats or those with severe fatty liver disease, and the blood concentration of haloperidol was determined 15 min, 1, 2, and 3 h following haloperidol administration. The concentration of haloperidol in the organs was determined 1, 2, and 3 h after the haloperidol administration. Additionally, the volume of the portal vein blood flow was measured 3 h after haloperidol administration. When given at the therapeutic dosage, the concentrations of haloperidol in both the blood and organs of the rats with fatty liver disease were significantly higher than those in the normal rats. However, when given at the toxic level, the blood and organ haloperidol concentrations 1 h after administration tended to be lower in the rats with fatty liver disease than those in the normal rats; these lower haloperidol levels returned to be the levels in the normal rats 3 h after the administration of haloperidol. The volume of the portal vein blood flow significantly increased following the toxic haloperidol dose as compared with the volume pre-administration and following the therapeutic haloperidol dose in the normal rats. However, the volume did not change after the toxic or the therapeutic dose of haloperidol compared with pre-administration in rats with severe fatty liver disease, although it was significantly higher than in the normal rats. The pathway for haloperidol metabolism might have been saturated before the administration of haloperidol in rats with fatty liver disease; thus, it is possible that the blood concentration of haloperidol tends to be much higher in individuals with severe fatty liver disease than in those with normal livers in an inverse proportion to the dosage of haloperidol.

Pulmonary fat embolization as a diagnostic finding for heat exposure

The aim of this study was to examine whether the detection of pulmonary fat embolization is valid as a significant indicator of heat exposure in forensic autopsies. In 54 cases where there was no evidence of fracture, burn or pancreatitis, 25 cases (46.3%) showed pulmonary fat embolization, the degree of which was pathohistologically classified as slight in all cases. Among the 25 cases where the pulmonary fat embolization was detected, the individual had died under a high ambient temperature in 14 cases (56%). Based on logistic regression analysis, pulmonary fat embolization was found to be associated with a high ambient temperature, but not associated with coronary arteriosclerosis, fatty infiltration in the liver, severe infectious diseases, intracranial hemorrhage or the detection of methamphetamine in the blood. Further investigations are necessary before these findings can be applied in forensic autopsy cases; however, it is likely that the detection of pulmonary fat embolization is valuable as one of the diagnostic findings indicating antemortem heat exposure.

Gene expression on liver toxicity induced by administration of haloperidol in rats with severe fatty liver

Sudden deaths are often encountered in schizophrenic patients prescribed with antipsychotic drugs, and fatty liver may be more prevalent among patients with schizophrenia. The aim of this study is to investigate the adverse effects of antipsychotic drugs on fatty liver. We administered haloperidol intraperitoneally to fatty liver rats and examined the mRNA expression in the liver. Basic expressions of cytochrome P450 (CYP)1A2, CYP2C11 and CYP3A2 decreased, and response of these CYPs to haloperidol was reduced in the fatty liver. Metabolism of haloperidol was also suppressed in the fatty liver rats. Moreover, hepatic injury by administration of haloperidol was shown pathohistologically and molecular-biologically in severe fatty liver. These results suggest that fatty liver increases susceptibility to adverse effects of haloperidol, possibly leading to life-threatening events. It should be noted by clinicians that excessive dose of antipsychotic drugs may be more harmful in patients with fatty liver.

Relationship between pulmonary fat embolism and core body temperature in rats with a severe fatty liver

We previously demonstrated that pulmonary fat embolism was induced by elevation of the core body temperature, in rats with a fatty liver. The aim of the present examination was to investigate the core body temperature at which pulmonary fat embolism developed capillaries through exposure to a high temperature, in rats with a fatty liver. Following heat stress, pulmonary fat embolism was observed to a slight degree at a core body temperature of 41 and 42 degrees C, whereas the severity of pulmonary fat embolism was greatly increased and was classified as severe at a core body temperature of 43 degrees C. Moreover, the concentrations of aspartate aminotransferase and alanine aminotransferase within plasma were significantly increased at a core body temperature of 43 degrees C. These results clearly indicate that the development of pulmonary fat embolism could be related to hyperthermia at above 42 degrees C following heat stress, and that fat emboli may be derived from the fatty liver itself. It is thus likely that pulmonary fat embolism can be considered as one form of evidence of hyperthermia in an individual with a fatty liver.

Vulnerability of experimentally induced fatty liver to heat stress in rats

BACKGROUND

The aim of this study was to confirm the vulnerability of fatty liver to heat stress using fatty liver rats from the viewpoint of the induction of apoptosis.

METHODS

We exposed rats with and without a fatty liver to heat stress and then looked for apoptotic cells within the liver tissue using two apoptosis detection kits. We also determined the mRNA expression of heat shock protein (HSP) 70, caspase-3, bcl-2, and bax using a quantitative reverse transcription-polymerase chain reaction method.

RESULTS

Following heat stress, apoptosis was strongly visible in the fatty liver comparing with that noted in the normal liver. The expression of HSP70 was increased following heat stress in both livers, but the volume of its expression was significantly less in the fatty liver than in the normal liver. The ratio of bcl-2/bax expression tended to increase in the normal liver but decrease in the fatty liver following heat stress. Caspase-3 demonstrated no significant change following heat stress in both livers.

CONCLUSIONS

The detection of apoptosis, together with changes in the mRNA expression of HSP70 and the expression ratio bcl-2/bax mRNA may indicate vulnerability of a fatty liver to heat stress and may support the hypothesis that morphologic change is induced in a fatty liver by exposure to heat stress. These results suggest that fatty liver may be more vulnerable to heat stress than normal liver.