A randomised, placebo- and active-controlled dose-finding study of aclidinium bromide administered twice a day in COPD patients.

This Phase IIb, double-blind, double-dummy, placebo- and active-comparator-controlled crossover study (ClinicalTrials.gov identifier: NCT01120093) assessed efficacy and safety of three doses of aclidinium bromide in patients with moderate to severe chronic obstructive pulmonary disease. Patients were randomised to one of five treatment sequences each consisting of twice-daily (BID) aclidinium 100 µg, 200 µg, 400 µg (via Genuair®*), formoterol 12 µg (via Aerolizer®) and matched placebo for 7 days, with a 5- to 9-day washout period. Primary endpoint was mean change from baseline in forced expiratory volume in 1 s (FEV1) normalised area under the curve (AUC)0-12 on Day 7. Secondary endpoints were: change from baseline in FEV1 normalised AUC12-24, FEV1 normalised AUC0-24 and morning pre-dose FEV1 on Day 7. Adverse events were monitored throughout the study. Of 79 randomised patients, 68 (86.1%) completed the study. After 7 days of treatment, aclidinium and formoterol produced statistically significantly greater changes from baseline in FEV1 normalised AUC0-12 vs placebo (p<0.0001). FEV1 normalised AUC12-24, FEV1 normalised AUC0-24, and morning pre-dose FEV1 were also statistically significantly greater with all aclidinium doses vs placebo (p<0.0001). Improvements in primary and secondary endpoints were statistically significantly greater with aclidinium 400 µg vs 100 µg. The safety profile of aclidinium was comparable to placebo. These results demonstrated that twice-daily aclidinium produced dose-dependent clinically meaningful improvements in FEV1 compared with placebo. This study also confirmed the use of an aclidinium BID dosing regimen and established aclidinium 200 µg and 400 µg as suitable doses for further investigation in Phase III trials.

Peak inspiratory flow through the Genuair inhaler in patients with moderate or severe COPD.

The Genuair inhaler is a new multidose dry powder inhaler for the delivery of aclidinium bromide - a novel, long-acting, muscarinic antagonist in development for the treatment of chronic obstructive pulmonary disease (COPD). The primary aim of this study was to assess the inspiratory flow characteristics through Genuair in patients with moderate or severe COPD. Using a three-period cross-over design, 48 patients were randomised to inhale placebo powder through Genuair, HandiHaler A (slow, deep inhalation as per manufacturer's instructions) or HandiHaler B (fast, forceful inhalation). Three measurements of peak inspiratory flow (PIF), 10min apart, were recorded for each method of administration. The highest and average PIFs for the three attempts (mean+/-standard deviation) generated through the Genuair inhaler were 97.7+/-15.7 and 92.0+/-15.4L/min, respectively. Furthermore, 97% of inhalations with the Genuair inhaler were successful (activation of trigger threshold mechanism) and optimal (PIF> or =45L/min). The highest and average PIFs generated through HandiHaler A and B were significantly lower than with the Genuair inhaler. In conclusion, patients with moderate or severe COPD were able to generate sufficient inspiratory airflow through the Genuair inhaler to reliably inhale the full dose and reset the inhaler.

Mitochondrial function in heart muscle from patients with idiopathic dilated cardiomyopathy.

OBJECTIVE: To study the mitochondrial respiratory chain enzyme activities in patients with idiopathic dilated cardiomyopathy (IDC). METHODS: Mitochondrial respiratory chain enzyme activities were assessed spectrophotometrically in left ventricular tissue of 17 patients with IDC undergoing cardiac transplantation, as well as in two groups of controls: a group of six patients suffering from ischemic dilated cardiomyopathy (IC) also undergoing cardiac transplantation, and a group of 17 organ donors considered normal from a cardiac point of view. Cytochrome b gene from three IDC patients whose complex III activity was particularly low and from three controls was also sequenced. RESULTS: We found that complex III enzymatic activity was lower not only in IDC but also in IC patients when compared with normal controls. When analysing cytochrome b gene we only found neutral polymorphisms previously described. CONCLUSIONS: In view of such results, we believe that the decrease of respiratory chain complex III activity found in some cases of IDC is a secondary phenomenon, and not due to a primary mitochondrial disease.

Oxidative damage on lymphocyte membranes is increased in patients suffering from acute carbon monoxide poisoning.

Increased oxidative damage seems to be a relevant mechanism in the pathophysiology of patients with an acute carbon monoxide (CO) poisoning. We have investigated the degree of membrane oxidative damage through the assessment of lipid peroxidation in circulating lymphocytes from five patients acutely intoxicated by CO. Since mitochondria are a major source of reactive oxygen species and mitochondrial cytochrome c oxidase (COX) has been reported to be inhibited after acute CO poisoning, we have also assessed the lymphocyte COX activity and its relationship with the degree of lipid peroxidation. Data were compared with those from 32 non-smoker healthy controls comparable in terms of age, gender and physical activity. In intoxicated patients, we have found a significant increase of lipid peroxidation compared to control individuals (P < 0.05), as well as a marked COX inhibition (P < 0.001). Both parameters showed a positive, nearly significant correlation (r = 0.81, P = 0.09). We conclude that oxidative damage of lymphocyte membranes is increased after acute CO poisoning, and suggest that such increase could be partially mediated by mitochondrial COX inhibition caused by CO.

Absence of mitochondrial dysfunction in polymyalgia rheumatica. Evidence based on a simultaneous molecular and biochemical approach.

OBJECTIVE: To investigate the molecular and biochemical profile of skeletal muscle mitochondria of patients with isolated polymyalgia rheumatica (PMR). PATIENTS AND METHODS: We included patients with a recent diagnosis of PMR and as control healthy individuals submitted to orthopedic surgery. Skeletal muscle was obtained from quadriceps, thus was mitochondria immediately isolated. Long polymerase chain reaction and Southern blot transference were performed to detect deleted mtDNA molecules. Mitochondrial oxidative activity using different substrates and individual enzyme activity of respiratory chain complexes were assessed to search for any biochemical dysfunction. RESULTS: Fifty-one individuals (PMR=25, controls=26) were included. Mean age was 72 (11) years; 45% were females. We found no significant increase of deleted mtDNA molecules in PMR patients compared to controls. Both groups differed neither on oxygen consumption (p=NS for all substrates) nor enzymatic activity (p=NS for all complexes). CONCLUSIONS: Skeletal muscle mitochondria are molecularly and biochemically unaffected in PMR.

Skeletal muscle mitochondrial function in polymyalgia rheumatica and in giant cell arteritis.

OBJECTIVE: To ascertain whether mitochondrial function is impaired in polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). PATIENTS AND METHODS: Thirteen patients suffering from isolated PMR, 19 from GCA (eight with and 11 without PMR) and 25 healthy people submitted to orthopaedic surgery were included. Skeletal muscle was obtained from the quadriceps by open biopsy. Mitochondrial histological abnormalities were assessed on Gomori's trichrome staining and on cytochrome c oxidase and succinic dehydrogenase reactions. Biochemical studies consisted of polarographic measurement of oxidative activity using complex I, II, III and IV substrates, and spectrophotometric determination of individual enzymatic activity of such complexes. RESULTS: We did not find differences among groups either with respect to the percentage of histological or histochemical abnormalities [P = not significant (NS) for all stainings and reactions], oxidative capacity (P = NS for all substrates) or individual enzymatic activities (P = NS for all complexes). CONCLUSION: Skeletal muscle mitochondria remain histologically and functionally unaffected in PMR and in GCA.

Localization and mobility of coenzyme Q in lipid bilayers and membranes.

We have studied the mobility of coenzyme Q (CoQ) in lipid bilayers and mitochondrial membranes in relation to the control of electron transfer activities. A molecular dynamics computer simulation in the vacuum yielded a folded structure for CoQ10, with a length of only 21 A. Using this information we were able to calculate diffusion coefficients in the range of 10(-6) cm2/s in good agreement with those found experimentally by fluorescence quenching of pyrene derivatives. To investigate if CoQ diffusion may represent the rate-limiting step of electron transfer, we reconstituted complexes I and III and assayed the resulting NADH-cytochrome c reductase activity in presence of different CoQ10 levels and at different distances between complexes; the experimental turnovers were higher than the collision frequencies calculated using diffusion coefficients of 10(-9) cm2/s but compatible with values found by us by fluorescence quenching. Since the experimental turnovers are independent of the distance between complexes, we conclude that CoQ diffusion is not rate-limiting for electron transfer.

Smoking disturbs mitochondrial respiratory chain function and enhances lipid peroxidation on human circulating lymphocytes.

Mitochondria constitute a source of reactive oxygen species. We tested whether mitochondrial function from human circulating lymphocytes is affected by smoking habit and if this could be associated with an increase in oxidative damage of biological membranes. We prospectively studied 35 smokers and 35 non-smoking healthy individuals matched by age and sex, with a similar physical activity. Individual enzyme activity of complexes II, III and IV of the mitochondrial respiratory chain (MRC) and of glycerol-3-phosphate dehydrogenase activity were measured spectrophotometrically. Intact cell respiration and oxidative rates after addition of pyruvate, succinate and glycerol-3-phosphate were assessed polarographically. Lipid peroxidation of biological membranes was assessed measuring the loss of cis-parinaric acid fluorescence. Results are expressed as means (+/-SD). Smokers showed a significant decrease in complex IV activity compared with non-smokers (112.8 +/- 40.9 versus 146.4 +/- 62.5 nmol/min/mg protein, respectively; 23% of inhibition; P = 0.01), while the rest of the complexes of MRC were unaffected. Conversely, oxidative rate with succinate, but not with the other substrates, was enhanced in smokers compared with non-smokers (16.7 +/- 10.4 versus 11.4 +/- 4.7 nmol oxygen/min/mg protein, respectively; 46% of activation; P = 0. 01). Lipid peroxidation of lymphocyte membranes was increased in smokers with respect to non-smokers (3.49 +/- 1.27 versus 4.39 +/- 1. 76 units of fluorescence/mg protein, respectively; 21% of increase; P = 0.03) and this increase correlated positively with succinate oxidation activation (R = 0.34, P = 0.02) and, to a lesser extent, with complex IV inhibition, although it did not reach statistical significance (R = 0.19, P = 0.18). In smokers, the MRC function of lymphocytes is disturbed and correlates with the degree of oxidative damage of membranes. This mitochondrial dysfunction could contribute to increased endogenous production of reactive oxygen species and could play a role in tobacco carcinogenicity.

Effects of general anaesthetic procedures on mitochondrial function of human skeletal muscle.

BACKGROUND: General anaesthetics inhibit mitochondrial function in animal models. However, very few studies have been performed in humans, and the results have not been conclusive. METHODS: We prospectively studied the oxygen consumption and the individual enzyme activity of each complex of the mitochondrial respiratory chain of skeletal muscle mitochondria in 54 healthy individuals who underwent general anaesthesia for orthopaedic surgery. The control group (n = 54) was made up of individuals submitted to the same orthopaedic procedure under regional anaesthesia (n = 31), and patients who underwent muscle biopsies for diagnostic purposes by local anaesthesia (n = 23). RESULTS: We found a significant decrease in the oxidation of glutamate (-36%), succinate (-25%) and ascorbate (-29%) in the general anaesthetic group compared with the controls (P < 0.001 for all substrates). The level of such inhibition was similar for volatile anaesthetics with strong (halothane) or weak (isoflurane) negative inotropic effect. By contrast, the enzymatic activity of all individual complexes and the coupling of oxidative phosphorylation did not differ between the two groups. CONCLUSION: We conclude that during general anaesthetic procedures there is an extensive inhibition of substrate oxidation in human muscle mitochondria, and that it is not caused by a direct effect on complexes of the mitochondrial respiratory chain or through uncoupling oxidative phosphorylation.

Histological and biochemical assessment of mitochondrial function in dermatomyositis.

OBJECTIVE: Mitochondrial dysfunction in idiopathic inflammatory myopathies (IIM) remains a controversial issue. The aim of the present study was to investigate the correlation between histological abnormalities and the biochemical function of the skeletal muscle mitochondria from patients with dermatomyositis (DM). METHOD: We evaluated 10 patients with a new diagnosis of DM and 15 healthy individuals, matched by age and gender. Muscle biopsy was routinely processed for histochemical studies and biochemical analysis of pure mitochondria. The percentages of ragged-red fibres (RRF), cytochrome c oxidase (COX)-negative fibres and succinic dehydrogenase (SDH) hyper-reactive fibres were calculated, oxygen utilization using different substrates was assessed polarographically, and enzymatic activity of individual complexes of the electron transport chain (ETC) and ATPase was measured spectrophotometrically. RESULTS: We found an increased percentage of COX-negative and SDH hyper-reactive fibres in DM patients (0.82 and 1.82%, respectively) compared to controls (0.26 and 0.22%; P < 0.05 and P = 0.001, respectively); however, oxidation rates of different substrates and enzymatic activities of ETC and ATPase did not differ significantly between both groups. CONCLUSION: The overall function of ETC from skeletal muscle mitochondria is not affected in DM.