phosphocreatine and Carotid-Artery-Diseases

The association between skeletal muscle mitochondrial function and CVD risk in healthy subjects is unknown.. Forty subjects were evaluated for CVD risk with lipid profile, oral glucose tolerance test and measurement of carotid intima-media thickness (cIMT). Skeletal muscle mitochondrial function was determined by phosphocreatine recovery after sub-maximal exercise with (31)Phosphorous-MRS and represented as τPCr.. τPCr was positively associated with age (r=+0.41; P=0.009) and cIMT (r=+0.50; P=0.001) on univariate analyses. In multivariate regression analysis controlling for age, the association between τPCr and cIMT remained significant (β=0.003; P=0.03). This association remained significant after controlling for traditional risk factors for CVD including age, gender, tobacco use, BMI, blood pressure, cholesterol and fasting glucose in a combined model (β=0.003; P=0.04; R(2)=0.53; P=0.008 for overall model).. These data suggest a novel association between skeletal muscle τPCr and increased cIMT, independent of age or traditional CVD risk factors.

Topics: Adult; Cardiovascular Diseases; Carotid Arteries; Carotid Artery Diseases; Exercise Test; Female; Humans; Lipids; Male; Middle Aged; Mitochondria, Muscle; Muscle, Skeletal; Phosphocreatine; Tunica Intima; Tunica Media

By combining immunohistochemical technique with microassay methods, we analyzed regional energy metabolism in vulnerable and tolerant areas of gerbil brains during evolution of neuronal damage after bilateral common carotid artery occlusion for 10 min with subsequent reperfusion. Four animals were used for each reperfusion period. Based on the information from the immunohistochemical examination, we dissected out vulnerable and tolerant subregions of the hippocampus, cerebral cortex, and thalamus from freeze-dried 20-microm-thick sections, and measured the levels of creatine phosphate (P-Cr), adenine nucleotides, guanine nucleotides, and purine bodies by HPLC, and the levels of glucose, glycogen, and lactate by an enzyme-immobilized column method. There were no significant differences in the levels of metabolites between vulnerable and tolerant subregions of control brains. After reperfusion, both vulnerable and tolerant subregions recovered preischemic metabolic profiles by 2 days. Although the regional differences between vulnerable and tolerant subregions were minimal at each reperfusion period, there were delays in the recovery of P-Cr, ATP, and/or total adenine nucleotides in all vulnerable subregions. A decline of P-Cr, ATP, and GTP levels without change in %ATP, AMP, or purine bodies occurred after reperfusion for 3 days, coinciding with the development of immunohistochemical damage by the immunoreaction for microtubule-associated protein 1A. The results supported the notion that subtle but sustained impairment of energy metabolism caused by mitochondrial dysfunction in the early reperfusion period might trigger delayed neuronal death in vulnerable subregions.

Topics: Adenine Nucleotides; Animals; Arterial Occlusive Diseases; Brain; Carotid Artery Diseases; Energy Metabolism; Female; Gerbillinae; Glucose; Immunohistochemistry; Male; Microtubule-Associated Proteins; Phosphocreatine; Reperfusion Injury

The present study tests the hypothesis that ketamine, a dissociative anesthetic known to be a non-competitive antagonist of the NMDA receptor, will attenuate hypoxic-ischemic damage in neonatal rat brain. Studies were performed in 7-day-old rat pups which were divided into four groups. Animals of the first group, neither ligated nor exposed to hypoxia, served as controls. The second group was exposed to hypoxic-ischemic conditions and sacrificed immediately afterwards. Animals of the third and fourth groups were treated either with saline or ketamine (20 mg/kg, i.p.) in four doses following hypoxia. Hypoxic-ischemic injury to the left cerebral hemisphere was induced by ligation of the left common carotid artery followed by 1 h of hypoxia with 8% oxygen. Measurements of high energy phosphates (ATP and phosphocreatine) and amino acids (glutamate and glutamine) and neuropathological evaluation of the hippocampal formation were used to assess the effects of hypoxia-ischemia. The combination of common carotid artery ligation and exposure to an hypoxic environment caused major alterations in the ipsilateral hemisphere. In contrast, minor alterations in amino acid concentrations were observed after the end of hypoxia in the contralateral hemisphere. These alterations were restored during the early recovery period. Post-treatment with ketamine was associated with partial restoration of energy stores and amino acid content of the left cerebral hemisphere. Limited attenuation of the damage to the hippocampal formation as demonstrated by a reduction in the number of damaged neurons was also observed. These findings demonstrate that systemically administered ketamine after hypoxia offers partial protection to the newborn rat brain against hypoxic-ischemic injury.

Topics: Adenosine Triphosphate; Amino Acids; Animals; Animals, Newborn; Body Weight; Brain; Brain Ischemia; Carotid Artery Diseases; Female; Functional Laterality; Glutamic Acid; Glutamine; Hypoxia, Brain; Ketamine; Male; Neurons; Neuroprotective Agents; Phosphocreatine; Rats; Rats, Wistar; Time Factors

We examined metabolic and functional changes when forebrain ischemia was induced in stroke-prone spontaneously hypertensive rats by bilateral carotid artery occlusion. In addition, the protective effect of clentiazem was evaluated in this model.. Rats were anesthetized with urethane. Cerebral blood flow was measured with a laser Doppler flowmeter. Cerebral high-energy phosphates and intracellular pH were measured by phosphorus magnetic resonance spectroscopy. Electroencephalographic activity was evaluated as the summation of its amplitude. These parameters were monitored during a 30-minute period of ischemia and recirculation. Clentiazem was given orally as pretreatment (10 mg/kg twice a day for 3.5 days).. Bilateral carotid occlusion caused a decrease in cerebral blood flow to approximately 5% of the preischemic level and the disappearance of electroencephalographic activity. Occlusion also caused a decrease in ATP and phosphocreatine (to 48.7 +/- 4.3% and 23.7 +/- 2.2% of preischemic levels, respectively) as well as intracellular pH (from 7.3 +/- 0.1 to 6.0 +/- 0.1). During recirculation the reversal of these changes was variable: high-energy phosphates were partially restored, but electroencephalographic activity and intracellular pH showed little improvement. Hypoperfusion (55.7 +/- 11.5% of the preischemic flow) developed after reactive hyperemia. Pretreatment with clentiazem lessened the decrease in cerebral blood flow (control, 4.8 +/- 1.4%; clentiazem, 14.1 +/- 4.1% of the preischemic level; P < .05) and prevented the disappearance of electroencephalographic activity in some rats during ischemia. Clentiazem also prevented postischemic hypoperfusion and accelerated the restoration of high-energy phosphates, intracellular pH, and electroencephalographic activity during recirculation.. Carotid artery occlusion induced stable forebrain ischemia in stroke-prone spontaneously hypertensive rats. Clentiazem improved the metabolic and functional disturbances that occurred in this ischemic model, and its beneficial effect appeared to be due mainly to the relative preservation of cerebral blood flow during carotid occlusion.

Topics: Adenosine Triphosphate; Analysis of Variance; Animals; Antihypertensive Agents; Arterial Occlusive Diseases; Blood Pressure; Brain; Brain Ischemia; Carbon Dioxide; Carotid Artery Diseases; Cerebral Arteries; Cerebral Cortex; Cerebrovascular Circulation; Cerebrovascular Disorders; Diltiazem; Disease Susceptibility; Electroencephalography; Energy Metabolism; Heart Rate; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Male; Oxygen; Partial Pressure; Phosphocreatine; Rats; Rats, Inbred SHR; Regional Blood Flow; Time Factors; Tissue Distribution

Bilateral ligation of common carotid arteries sharply decreases volume blood flow and oxygen consumption in the cortex, in diencephalon and midbrain whereas inducing no changes in the cerebellum and medulla oblongata. The same is true for intensity of metabolism of both total and separate fractions of phospholipids. This suggests that the changes of phospholipid metabolism in neural tissue depend on the degree of its blood supply disturbance and duration of the ischemia.

Topics: Adenine Nucleotides; Animals; Brain; Brain Chemistry; Brain Ischemia; Carotid Artery Diseases; Lactates; Male; Oxygen Consumption; Phosphocreatine; Phospholipids; Rats; Time Factors