Objective: to evaluate the impact of Leiden mutation on the course of severe acute pancreatitis. Subjects and methods. One hundred and twelve people were examined. Group 1 comprised 50 patients diagnosed with severe acute pancreatitis with out coagulation factor V (Leiden) mutation. Group 2 included 42 patients with severe acute pancreatitis who were found to have Leiden mutation. Acute pancreatitis was first diagnosed in both groups. Group 3 consisted of 20 apparently healthy individuals (a control group). The severity of the underlying disease was determined in accordance with the clinical and lab oratory parameters recommended by the I. I. Dzhanelidze Saint Petersburg Research Institute of Emergence Care. Results. This investigation revealed an association of Leiden mutation with trends in the development of acute pancreatitis. Group 2 exhibited a more severe disease: large focal pancreatic necrosis was twice more common and infectious complica tions developed more frequently; more aggressive and rad ical treatments were more often used. The patients with Leiden mutation had higher mortality rates (33% in the Leiden mutation group and 24% in the non mutation group.

SummaryTranscription factor Nrf2 and its repressor Keap1 regulate a network of cytoprotective genes involving more than 1% of the genome, their best known targets being drug-metabolizing and antioxidant genes. Here we demonstrate a novel role for this pathway in directly regulating mitochondrial bioenergetics in murine neurons and embryonic fibroblasts. Loss of Nrf2 leads to mitochondrial depolarisation, decreased ATP levels and impaired respiration, whereas genetic activation of Nrf2 increases the mitochondrial membrane potential and ATP levels, the rate of respiration and the efficiency of oxidative phosphorylation. We further show that Nrf2-deficient cells have increased production of ATP in glycolysis, which is then used by the F1Fo-ATPase for maintenance of the mitochondrial membrane potential. While the levels and in vitro activities of the respiratory complexes are unaffected by Nrf2 deletion, their activities in isolated mitochondria and intact live cells are substantially impaired. In addition, the rate of regeneration of NADH after inhibition of respiration is much slower in Nrf2-knockout cells than in their wild-type counterparts. Taken together, these results show that Nrf2 directly regulates cellular energy metabolism through modulating the availability of substrates for mitochondrial respiration. Our findings highlight the importance of efficient energy metabolism in Nrf2-mediated cytoprotection.

Disrupted energy metabolism, in particular reduced activity of cytochrome oxidase (EC 1.9.3.1), a-ketoglutarate dehydrogenase (EC 1.2.4.2) and pyruvate dehydrogenase (EC 1.2.4.1) have been reported in post-mortem Alzheimer's disease brain. b-Amyloid is strongly implicated in Alzheimer's pathology and can be formed intracellularly in neurones. We have investigated the possibility that b-amyloid itself disrupts mitochondrial function. Isolated rat brain mitochondria have been incubated with the b-amyloid alone or together with nitric oxide, which is known to be elevated in Alzheimer's brain. Mitochondrial respiration, electron transport chain complex activities, a-ketoglutarate dehydrogenase activity and pyruvate dehydrogenase activity have been measured. b-Amyloid caused a signi®cant reduction in state 3 and state 4 mitochondrial respiration that was further diminished by the addition of nitric oxide. Cytochrome oxidase, a-ketoglutarate dehydrogenase and pyruvate dehydrogenase activities were inhibited by b-amyloid. The K m of cytochrome oxidase for reduced cytochrome c was raised by b-amyloid. We conclude that b-amyloid can directly disrupt mitochondrial function, inhibits key enzymes and may contribute to the de®ciency of energy metabolism seen in Alzheimer's disease.

Abstract:Within the CNS and under normal conditions, nitric oxide ('NO) appears to be an important physiological signalling molecule. Its ability to increase cyclic GMP concentration suggests that 'No is implicated in the regulation of important metabolic pathways in the brain. Under certain circumstances N0 synthesis may be excessive and N0 may become neurotoxic. Excessive glutamatereceptor stimulation may lead to neuronal death through a mechanism implicating synthesis of both 'No and superoxide (02') and hence peroxynitrite (ONOO ) formation. In response to lipopolysaccharide and cytokines, glial cells may also be induced to synthesize large amounts of 'No, which may be deleterious to the neighbouring neurones and oligodendrocytes. The precise mechanism of 'No neurotoxicity is not fully understood. One possibility is that it may involve neuronal energy deficiency. This may occur by ONOO interfering with key enzymes of the tricarboxylic acid cycle, the mitochondrial respiratory chain, mitochondrial calcium metabolism, or DNA damage with subsequent activation of the energy-consuming pathway involving poly(ADPribose) synthetase. Possible mechanisms whereby ONOO impairs the mitochondrial respiratory chain and the relevance for neurotoxicity are discussed. The intracellular content of reduced glutathione also appears important in determining the sensitivity of cells to ONOOproduction. lt is concluded that neurotoxicity elicited by excessive 'NO production may be mediated by mitochondrial dysfunction leading to an energy deficiency state.

The effect of the neurotoxic nitric oxide derivative, the peroxynitrite anion (ONOO−), on the activity of the mitochondrial respiratory chain complexes in cultured neurones and astrocytes was studied. A single exposure of the neurones to ONOO− (initial concentrations of 0.01–2.0 mM) caused, after a subsequent 24‐h incubation, a dose‐dependent decrease in succinate‐cytochrome c reductase (60% at 0.5 mM) and in cytochrome c oxidase (52% at 0.5 mM) activities. NADH‐ubiquinone‐1 reductase was unaffected. In astrocytes, the activity of the mitochondrial complexes was not affected up to 2 mM ONOO−. Citrate synthase was unaffected in both cell types under all conditions studied. However, lactate dehydrogenase activity released to the culture medium was increased by ONOO− in a dose‐dependent manner (40% at 0.5 mM ONOO−) from the neurones but not from the astrocytes. Neuronal glutathione concentration decreased by 39% at 0.1 mM ONOO−, but astrocytic glutathione was not affected up to 2 mM ONOO−. In isolated brain mitochondria, only succinate‐cytochrome c reductase activity was affected (22% decrease at 1 mM ONOO−). We conclude that the acute exposure of ONOO− selectively damages neurones, whereas astrocytes remain unaffected. Intracellular glutathione appears to be an important factor for ameliorating ONOO−‐mediated mitochondrial damage. This study supports the hypothesis that the neurotoxicity of nitric oxide is mediated through mitochondrial dysfunction.