Dose-response effects of TPI ASM8 in asthmatics after allergen

BACKGROUND

TPI ASM8 contains two modified antisense oligonucleotides (AON) targeting the beta subunit (β(c) ) of the IL-3, IL-5, GM-CSF receptors and the chemokine receptor CCR3. A previous study suggested that TPI ASM8 had broader effects than just inhibition of eosinophils in asthmatics.

OBJECTIVE

We assessed whether TPI ASM8 caused a dose-dependent attenuation in the inflammatory and physiological changes after inhaled allergen challenge (AIC).

METHODS

This single-center, open-label, stepwise-ascending dose study was conducted in fourteen stable, mild allergic asthmatics. Following placebo AIC, subjects underwent AIC after 4 days treatment with 1, 2, and 4 mg BID and finally 8 mg once daily (OD) of TPI ASM8, inhaled via the I-Neb™ nebuliser. Treatments were separated by 2-3-week washout periods.

RESULTS

TPI ASM8 was safe and well tolerated at all doses. TPI ASM8 8 mg OD reduced eosinophils in sputum after AIC (by 60.9% at 7 h and 68.4% at 24 h post-AIC, P=0.016 and P=0.007, respectively). Additionally, TPI ASM8 8 mg OD significantly attenuated the early and late airway responses as shown by the reduction in the area under the curve by 45% (P=0.016) and 59%, (P=0.0015), respectively, the increase in eosinophil cationic protein (ECP) by up to 57% (P=0.021), and airway responsiveness to methacholine by more than 1 doubling dose (P=0.012). A dose-response relationship was noted, and efficacy was maintained with once per day administration.

CONCLUSIONS

TPI ASM8 attenuated a broad range of inflammatory and physiological changes after AIC, suggesting that CCR3, IL-3, and GM-CSF also are important targets for the management of asthma.

Respiratory sensations, cardiovascular control, kinaesthesia and transcranial stimulation during paralysis in humans

1. To determine whether discomfort associated with breathing (dyspnoea) is related to the chemical drive to breath, three subjects were totally paralysed while fully conscious. Subjective responses to a rising CO2 stimulus were obtained during rebreathing, rebreathing with CO2 added, and breath holding. Dyspnoea was measured with a 10-point Borg scale. 2. Following nasotracheal intubation and ventilation (oxygen saturation, O2,Sat, 98-100% and end-tidal CO2, PET,CO2, 30-40 mmHg), total neuromuscular blockade was induced by a rapid injection of atracurium (> 2.5 mg kg-1) and complete paralysis was maintained with an infusion (5 mg (kg h)-1). Paralysis was confirmed by abolition of the compound muscle action potentials of both the diaphragm and abductor hallucis evoked by supramaximal electrical stimulation of the relevant nerves. Communication via finger movement was preserved for the first 20-30 min following paralysis by inflation of a sphygmomanometer cuff on one arm. 3. Before and during complete paralysis, dyspnoea increased progressively during hypercapnia produced by rebreathing (with or without CO2 added to the circuit at 250 ml min-1). The mean PET,CO2 eliciting 'severe' dyspnoea was 46 mmHg during rebreathing, 42 mmHg during 'breath holding', and 52 mmHg during rebreathing with added CO2. There were no significant differences between the values obtained during paralysis and in the control study immediately before paralysis. The duration of breath holding was not prolonged by paralysis and the PET,CO2 at the 'break point' was not altered by paralysis. 4. Thus, dyspnoea is preserved following total neuromuscular blockade. This suggests that chemoreceptor activity, via the central neuronal activity which it evokes, can lead to discomfort in the absence of any contraction of respiratory muscles. 5. During paralysis, attempted contraction of arm, leg and trunk muscles increased heart rate and blood pressure. For attempted handgrip contractions, the increases in heart rate (range, 7-15 beats min-1) and mean arterial pressure (range, 20-32 mmHg) were similar to those recorded with actual contractions in trials immediately before paralysis. In one subject, graded increases in heart rate and blood pressure occurred for attempted contractions of 45 s duration over a range of intensities (0-100% maximal effort). 6. During complete paralysis, transcranial electromagnetic stimulation of the motor cortex produced illusory twitch-like movements of the wrist and digits. This also occurred in separate studies during complete ischaemic paralysis and anaesthesia of the forearm and hand.(ABSTRACT TRUNCATED AT 400 WORDS)

Randomised controlled trial of weightlifting exercise in patients with chronic airflow limitation

BACKGROUND PATIENTS: with chronic airflow obstruction are often limited by muscle fatigue and weakness. As exercise rehabilitation programmes have produced modest improvements at best a study was designed to determine whether specific muscle training techniques are helpful.

METHODS

Thirty four patients with chronic airflow limitation (forced expiratory volume in one second (FEV1) 38% of predicted values) were stratified for FEV1 to vital capacity (VC) ratio less than 40% and arterial oxygen desaturation during exercise and randomised to a control or weightlifting training group. In the experimental group training was prescribed for upper and lower limb muscles as a percentage of the maximum weight that could be lifted once only. It was carried out three times a week for eight weeks.

RESULTS

Three subjects dropped out of each group; results in the remaining 14 patients in each group were analysed. Adherence in the training group was 90%. In the trained subjects muscle strength and endurance time during cycling at 80% of maximum power output increased by 73% from 518 (SE69) to 898 (95) s, with control subjects showing no change (506 (86) s before training and 479 (89) s after training). No significant changes in maximum cycle ergometer exercise capacity or distance walked in six minutes were found in either group. Responses to a chronic respiratory questionnaire showed significant improvements in dyspnoea and mastery of daily living activities in the trained group.

CONCLUSIONS

Weightlifting training may be successfully used in patients with chronic airflow limitation, with benefits in muscle strength, exercise endurance, and subjective responses to some of the demands of daily living.