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

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

Effects of different levels of inosine-5'-monophosphate (5'-IMP) supplementation on the growth performance and meat quality of finishing pigs (75 to 100 kg).

This study aimed to assess the effects of dietary supplementation of inosine-5'-monophosphate (5'-IMP) on energy efficiency, growth performance, carcass characteristics, meat quality, oxidative status, and biochemical profile of blood plasma in finishing pigs. Fifty-four crossbred castrated male pigs were distributed in a randomized block design consisting of nine blocks, with six treatments per block and one animal per treatment per block. Experimental diets were as follows: positive control diet (PC, 3300 kcal ME/kg), negative control diet (NC, 3200 kcal ME/kg), and four diets prepared by supplementing the NC diet with 0.050%, 0.100%, 0.150%, or 0.200% 5'-IMP. Based on regression analysis, supplementation with 0.129% 5'-IMP increased average daily weight gain (1.30 kg). Backfat thickness, pH45minutes and redness of m. Longissimus Lumborum (LL) increased linearly with 5'-IMP supplementation level. Drip loss and pH at 24 h post-slaughter had a quadratic response to 5'-IMP supplementation. It is concluded that 5'-IMP supplementation positively influenced growth performance, carcass characteristics and LL meat quality in finishing barrows.

Harmful effects of chlorhexidine on hepatic metabolism.

Chlorhexidine (CHX) is an over-the-counter antiseptic amply used by the population. There are reports that CHX acts in mitochondria as an uncoupler and inhibitor. The purpose of this study was to investigate the short-term effects of CHX on hepatic metabolic pathways linked to energy metabolism in the perfused rat liver. The compound inhibited both glucose synthesis and the urea cycle. Oxygen consumption was raised at low concentrations (up to 10 µM) and diminished at higher ones. A pronounced diminution in the cellular ATP content was observed. Conversely, CHX stimulated glycolysis and enhanced leakage of cellular enzymes (lactate dehydrogenase and fumarase). In isolated mitochondria, this antiseptic inhibited pyruvate carboxylation, oxidases, and oxygen uptake at very low concentrations (2 µM) and promoted uncoupling. The results described herein raise great concerns about the safety of CHX, as the observed effects can induce hypoglycemia, lactic acidosis, ammonemia as well as cell membrane disruption.

Glycemic homeostasis and hepatic metabolism are modified in rats with global cerebral ischemia.

Cerebral ischemia-induced hyperglycemia has been reported to accentuate neurological damage following focal or global cerebral ischemia. Hyperglycemia found in rats following focal brain ischemia occurs in the first 24 h and has been claimed to be caused by increased liver gluconeogenesis and insulin resistance. However, liver gluconeogenesis and the mechanisms leading to hyperglycemia after global cerebral ischemia remain uncertain. This study investigated the glycemic homeostasis and hepatic metabolism in rats after transient four-vessel occlusion (4-VO)-induced global cerebral ischemia, an event that mimics to a certain degree the situation during cardiac arrest. Several metabolic fluxes were measured in perfused livers. Activities and mRNA expressions of hepatic glycolysis and glyconeogenesis rate-limiting enzymes were assessed as well as respiratory activity of hepatic isolated mitochondria. Global cerebral ischemia was associated with hyperglycemia and hyperinsulinemia 24 h after ischemia. Insulin resistance developed later and was prominent after the 5th day. Hepatic anabolism and catabolism were both modified in a complex and time-dependent way. Gluconeogenesis, ß-oxidation, ketogenesis and glycolysis were diminished at 24 h after ischemia. At 5 days after ischemia glycolysis had normalized, but gluconeogenesis, ketogenesis and ß-oxidation were accelerated. The overall metabolic modifications suggest that a condition of depressed metabolism was established in response to the new conditions generated by the cerebral global ischemia. Whether the modifications in the liver metabolism found in rats after the ischemic insult can be translated to individuals following global brain ischemia remains uncertain, but the results of this study are hoped to encourage further investigations.

Methyl Jasmonate Reduces Inflammation and Oxidative Stress in the Brain of Arthritic Rats.

Methyl jasmonate (MeJA), common in the plant kingdom, is capable of reducing articular and hepatic inflammation and oxidative stress in adjuvant-induced arthritic rats. This study investigated the actions of orally administered MeJA (75-300 mg/kg) on inflammation, oxidative stress and selected enzyme activities in the brain of Holtzman rats with adjuvant-induced arthritis. MeJA prevented the arthritis-induced increased levels of nitrites, nitrates, lipid peroxides, protein carbonyls and reactive oxygen species (ROS). It also prevented the enhanced activities of myeloperoxidase and xanthine oxidase. Conversely, the diminished catalase and superoxide dismutase activities and glutathione (GSH) levels caused by arthritis were totally or partially prevented. Furthermore, MeJA increased the activity of the mitochondrial isocitrate dehydrogenase, which helps to supply NADPH for the mitochondrial glutathione cycle, possibly contributing to the partial recovery of the GSH/oxidized glutathione (GSSG) ratio. These positive actions on the antioxidant defenses may counterbalance the effects of MeJA as enhancer of ROS production in the mitochondrial respiratory chain. A negative effect of MeJA is the detachment of hexokinase from the mitochondria, which can potentially impair glucose phosphorylation and metabolism. In overall terms, however, it can be concluded that MeJA attenuates to a considerable extent the negative effects caused by arthritis in terms of inflammation and oxidative stress.