Chlamydia pneumoniae antibodies and inflammatory reaction in patients with ischemic heart disease.

We studied the relationship between Chlamydia pneumoniae antibodies, C-reactive protein (CRP) and interleukine 8 (IL-8) in 87 patients with ischemic heart disease: 29 patients with acute myocardial infarction, 18 patients with unstable angina pectoris and 40 patients with stable effort angina. We determined in all patients IgG and IgA antibodies to Chlamydia pneumoniae, CRP and IL-8. Species specific antibodies to Chlamydia pneumoniae (IgG and IgA) were detected by indirect ELISA technique (Savyon Diagnostics Ltd, Israel). Interleukine-8 measured by a commercially available ELISA kit (CLB, Amsterdam, The Netherlands). CRP was determined by radial immunodiffusion (Mancini). The IgG antibodies were present in 25 patients (29%), the greatest percentage being noted in patients with unstable angina pectoris (50%). The IgA antibodies were present, as a sign of chronic Chlamydia pneumoniae infection, in 56% of the patients with IgG antibodies. CRP was positive in 52% of the 25 patients with positive IgG antibodies, but in only 34% of the 62 patients without IgG antibodies (p < 0.01). IL-8 was positive in 12% of the patients with IgG antibodies, and in 21% of the patients without IgG antibodies but the difference is not significant (p > 0.05). It is concluded that there is a relationship between the presence of the Chlamydia pneumoniae infection and inflammatory reaction in patients with ischemic heart disease, but the neutrophils are not implied in this process.

Hepatic mitochondrial proliferation in rats with secondary biliary cirrhosis: time course and mechanisms.

It is well known that the hepatic mitochondrial protein content is increased in rats 4 weeks after bile duct ligation. In the present study, we measured the time course of this increase and assessed the levels of selected mitochondrial messenger RNA (mRNA) species and the rate of mitochondrial protein synthesis by isolated mitochondria. Three days after surgery, the mitochondrial protein content was not significantly different between bile duct-ligated (BDL) and control rats, averaging 1,140 +/- 220 mg/liver in BDL and 1,260 +/- 50 mg/liver in sham-operated control rats. However, in comparison with control rats, it was increased in BDL rats by 35% at 7 days, by 81% at 14 days, and by 27% at 28 days after surgery. In vitro mitochondrial protein synthesis, which was assessed as the fractional incorporation of [35S]-methionine into mitochondrial protein, was not different between BDL and control rats at 3 days after surgery, but was decreased in BDL rats by 63% at 7 days, by 55% at 14 days, and by 36% at 28 days after surgery. Northern blot analysis revealed an increase in the mRNA levels of adenosine triphosphate (ATP)ase subunit 6 and apocytochrome b in BDL rats at day 7, but no significant differences between BDL and control rats in mitochondrial mRNA and ribosomal RNA species 14 and 28 days after surgery. These results show that the hepatic mitochondrial protein content rises early after surgery in BDL rats, but this rise cannot be ascribed to elevated rates of mitochondrial protein synthesis. Thus, increased synthesis of nuclearly encoded mitochondrial proteins and/or decreased degradation of mitochondrial proteins appear likely mechanisms that lead to the observed increase in the hepatic mitochondrial protein content in BDL rats.

Benzoic acid metabolism reflects hepatic mitochondrial function in rats with long-term extrahepatic cholestasis.

Benzoic acid metabolism, which is primarily a function of liver mitochondria, depending on the concentration of adenosine triphosphate (ATP), coenzyme A (CoA), and glycine in the mitochondrial matrix, was investigated in both rats with long-term cholestasis caused by bile duct ligation (BDL) and sham-operated control rats. In isolated liver mitochondria, hippurate production from benzoate in the presence of saturating glycine concentrations was reduced in BDL rats by 36% with L-glutamate as a source for ATP, by 21% in the presence of succinate, and by 31% in the presence of ATP plus oligomycine. This reduction in benzoate metabolism is in the same range as the previously observed reduction in the activity of the electron transport chain in liver mitochondria from BDL rats. The mitochondrial CoA pool, which can be rate-limiting for benzoic acid metabolism, was not different between BDL and control rats. The activity of benzoyl-CoA synthase, the enzyme catalyzing the rate-limiting step in benzoate metabolism, was reduced by 25%, and the activity of benzoyl-CoA:glycine N-transferase was reduced by 66% in BDL rats. The activity of benzoyl-CoA synthase was significantly inhibited by lithocholate, suggesting that hepatic accumulation of hydrophobic bile acids could contribute to the observed reduction of benzoate metabolism in BDL rats. Benzoate metabolism was also studied in vivo by monitoring the urinary hippurate excretion after intraperitoneal administration of benzoate (100 micromol/100 g of body weight). The time course of hippurate excretion was not different between BDL and control rats. Hippurate excretion over 24 hours after benzoate administration averaged 89.7 +/- 4.0% of the administered dose in BDL and 74.4 +/- 6.9% (mean +/- SEM, difference not significant) in control rats. This finding could be explained by an increase in mitochondrial protein in BDL rats, averaging 2.34 +/- 0.29 g per liver in BDL and 1.35 +/- 0.07 g per liver in control rats (mean +/- SEM, p < .05). Thus, the studies show that benzoate metabolism reflects mitochondrial function in BDL rats both in vivo and in vitro, and that mitochondrial proliferation compensates for the observed decrease in benzoic acid metabolism in isolated mitochondria in vitro.

Progressive decrease in tissue glycogen content in rats with long-term cholestasis.

Liver and skeletal muscle glycogen metabolism were investigated in rats 1 and 4 weeks after bile duct ligation (BDL) and in pair-fed, sham-operated control rats. Livers were subjected to morphometric analysis to express glycogen content and enzyme activities per mL hepatocytes. One week after BDL, the hepatic glycogen content was 28.8 +/- 13.8 versus 38.6 +/- 16.4 mg/mL hepatocyte in BDL and control rats, respectively. Total activity of glycogen synthase (50.2 +/- 7.0 vs. 63.5 +/- 9.4 mU/mL hepatocytes) and glycogen phosphorylase (59.4 +/- 12.9 vs. 90.8 +/- 18.9 U/mL) were significantly reduced in BDL whereas the active fraction of glycogen synthase (27 +/- 6 vs. 38 +/- 5%) but not of glycogen phosphorylase was reduced. The skeletal muscle glycogen content was not different between BDL and control rats. Four weeks after BDL, hepatic glycogen content was further reduced (20.5 +/- 14.2 vs. 52.9 +/- 6.4 mg/mL). Total activity of glycogen synthase (38.8 +/- 12.1 vs. 60.1 +/- 4.6 mU/mL hepatocytes) and glycogen phosphorylase (127 +/- 19 vs. 178 +/- 33 U/mL hepatocytes) were both reduced in BDL rats as were their corresponding active fractions (30 +/- 18 vs. 66 +/- 8% and 58 +/- 10 vs. 76 +/- 10). At this time point, the glycogen content in soleus muscle was decreased by 64% in BDL. The glucagon plasma concentration was increased in BDL rats at both time points. There were positive correlations between the volume fraction and both hepatic glycogen content and total activity of hepatic glycogen synthase. Plasma glucagon and the active fraction of hepatic glycogen synthase were negatively correlated. The current studies show a progressive decrease in the hepatic and skeletal muscle glycogen content in BDL rats. The observed decrease in the activities of glycogen synthase and phosphorylase suggest that reduced glycogen synthesis is the major mechanism leading to the reduction in the hepatic glycogen content in BDL rats.

Reduced antioxidative capacity in liver mitochondria from bile duct ligated rats.

Lipid peroxidation and antioxidative mechanisms were investigated in liver mitochondria from bile duct ligated rats (BDL rats) and correlated with the activity of enzyme complexes of the electron transport chain. In comparison to pair-fed control rats, BDL rats had increased concentrations of thiobarbituric acid reacting substances (TBARS) per gram of liver and per milligram of mitochondrial protein 3, 7, 14, and 28 days after surgery. The hepatic glutathione (GSH) content was decreased in BDL rats 28 days after surgery when expressed per gram of liver but equal between BDL and control rats when expressed per liver. The mitochondrial GSH content was decreased in BDL rats by 20% to 33% from day 7 after surgery. The concentrations of ubiquinone-9 and ubiquinone-10, substances involved in electron transport and efficient antioxidants, were both decreased in BDL rats 14 and 28 days after surgery per gram of liver and per milligram of mitochondrial protein. When expressed per liver, ubiquinone-9 was decreased in BDL rats from day 7 after surgery. In comparison with controls, the decrease in total mitochondrial ubiquinone content in BDL rats averaged 52% 14 days and 38% 28 days after surgery. The activity of the succinate:ferricytochrome c oxidoreductase (complexes II and III of the electron transport chain) was decreased in BDL rats at days 7, 14, and 28 after surgery, and the activity of the ferrocytochrome c:oxygen oxidoreductase (complex IV) was reduced at 14 and 28 days after surgery. The mitochondrial concentration of TBARS showed a negative and the concentrations of GSH and ubiquinone a positive correlation with the activity of the succinate:ferricytochrome c oxidoreductase.(ABSTRACT TRUNCATED AT 250 WORDS)

Ursodeoxycholate protects oxidative mitochondrial metabolism from bile acid toxicity: dose-response study in isolated rat liver mitochondria.

The effect of ursodeoxycholate and tauroursodeoxycholate on the toxicity of lipophilic bile acids (chenodeoxycholate and lithocholate) on the function of the electron transport chain was investigated in isolated rat liver mitochondria. At a concentration of 30 mumol/L, both chenodeoxycholate and lithocholate reduced state 3 oxidation rates and respiratory control ratios of L-glutamate, succinate and duroquinol. In contrast, ADP/O ratios of these substrates and oxidative metabolism of ascorbate were not significantly affected. Ursodeoxycholate did not impair mitochondrial oxidative metabolism up to concentrations of 100 mumol/L; at 300 mumol/L, however, it decreased state 3 oxidation rates and respiratory control ratios of L-glutamate, succinate and duroquinol. Tauroursodeoxycholate had no significant inhibitory effect on state 3 oxidation rates of L-glutamate and succinate at concentrations up to 300 mumol/L. When ursodeoxycholate (final concentration, 30 mumol/L or 100 mumol/L) was added to mitochondrial incubations containing chenodeoxycholate or lithocholate, the toxic effects of lipophilic bile acids on mitochondrial oxidative metabolism were partially reversed. However, 300 mumol/L ursodeoxycholate, in combination with chenodeoxycholate or lithocholate, exhibited greater toxicity compared with incubations containing only the individual bile acids. In contrast to ursodeoxycholate, tauroursodeoxycholate did not reduce the toxic effects of chenodeoxycholate or lithocholate on mitochondrial metabolism. Ursodeoxycholate (100 mumol/L) significantly decreased the incorporation of chenodeoxycholate into mitochondrial membranes, whereas the decrease in lithocholate incorporation was not statistically significant. These studies demonstrate that ursodeoxycholate, but not tauroursodeoxycholate, decreases the toxicity of lipophilic bile acids on the function of the electron but increases bile acid-induced mitochondrial toxicity at higher concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Development and evaluation of a spectrophotometric assay for complex III in isolated mitochondria, tissues and fibroblasts from rats and humans.

A spectrophotometric method to assay the activity of complex III in isolated mitochondria, tissues and fibroblasts from patients and rats has been developed and validated. Decylubiquinol was shown to be a suitable substrate with a saturating concentration between 100 and 200 mumol/l. The optimal pH was found to range from 7.4 to 8.0. The enzyme reaction was linear for incubations containing up to 15 micrograms/ml mitochondrial protein, 250 micrograms/ml liver tissue, 375 micrograms/ml skeletal muscle or 100 micrograms/ml fibroblast protein. Intraday and interday variability of the assay for different enzyme sources was below 15% and 10%, respectively. Assessment of complex III activity in liver and fibroblasts from patients with signs of mitochondrial dysfunction revealed the usefulness of the newly developed assay in the diagnosis of complex III deficiency.

Mechanisms of impaired hepatic fatty acid metabolism in rats with long-term bile duct ligation.

Hepatic metabolism of fatty acids is impaired in experimental animals with long-term bile duct ligation. To characterize the underlying defects, fatty acid metabolism was investigated in isolated hepatocytes and isolated liver mitochondria from rats subjected to long-term bile duct ligation or sham surgery. After starvation for 24 hr, the plasma beta-hydroxybutyrate concentration was decreased in rats with bile duct ligation as compared with control rats. Production of beta-hydroxybutyrate from butyrate, octanoate and palmitate by hepatocytes isolated from rats subjected to bile duct ligation was also decreased. Liver mitochondria from rats subjected to bile duct ligation showed decreased state 3 oxidation rates for L-glutamate, succinate, duroquinone, and fatty acids but not for ascorbate as substrate. State 3u oxidation rates (uncoupling with dinitrophenol) and activities of mitochondrial oxidases were also decreased in mitochondria from rats subjected to bile duct ligation. Direct assessment of the activities of the subunits of the electron transport chain revealed reduced activities of complex I, complex II and complex III in mitochondria from rats subjected to bile duct ligation. Activities of the beta-oxidation enzymes specific for short-chain fatty acids were all reduced in rats subjected to bile duct ligation. Mitochondrial protein content per hepatocyte was increased by 32% in rats subjected to bile duct ligation compared with control rats. Thus the studies directly demonstrate mitochondrial defects in fatty acid oxidation in rats subjected to bile duct ligation, which explain decreased ketosis during starvation.

Toxicity of bile acids on the electron transport chain of isolated rat liver mitochondria.

The toxicity of hydrophilic (cholate) and lipophilic (deoxycholate, chenodeoxycholate, and lithocholate) bile acids on the function of the electron transport chain was investigated in intact and disrupted rat liver mitochondria. In intact mitochondria, lipophilic bile acids used at a concentration of 100 mumol/L (0.1 mumol/mg protein) inhibited state 3 and state 3u (dinitrophenol-uncoupled) oxidation rates for L-glutamate, succinate, duroquinol or ascorbate/N,N,N',N'-tetramethyl-p-phenylenediamine as substrates. In contrast, state 4 oxidation rates and ADP/oxygen ratios were not significantly affected. At a bile acid concentration of 10 mumol/L (0.01 mumol/mg protein), the state 3 oxidation rate for L-glutamate was decreased in the presence of deoxycholate, chenodeoxycholate or lithocholate, whereas only lithocholate inhibited state 3 oxidation for succinate or duroquinol. In broken mitochondria, inhibition of oxidative metabolism was found for NADH or duroquinol as substrate in the presence of 100 mumol/L lithocholate (0.2 mumol/mg protein) and for duroquinol in the presence of 100 mumol/L chenodeoxycholate. Direct assessment of the activities of the enzyme complexes of the electron transport chain revealed decreased activities of complex I and complex III in the presence of 100 mumol/L deoxycholate or chenodeoxycholate or 10 mumol/L lithocholate. Inhibition of complex IV required higher bile acid concentrations (300 mumol/L for chenodeoxycholate or 30 mumol/L for lithocholate), and complex II was not affected. Both chenodeoxycholate and lithocholate were incorporated into mitochondrial membranes. The phospholipid content of mitochondrial membranes decreased in incubations containing 100 mumol/L (0.1 mumol/mg protein) chenodeoxycholate but was not affected in the presence of 100 mumol/L lithocholate.(ABSTRACT TRUNCATED AT 250 WORDS)