Late Breaking Abstract - Muscle carnosine in patients with COPD in comparison to age- and gender matched healthy controls: a cross-sectional study

Background: Carnosine (CAR), a histidine containing dipeptide, is abundantly present in skeletal muscle. It has been shown to have interesting antioxidant potential as is it can scavenge oxidative stress. As basal and exercise-induced oxidative stress is seemingly present in the skeletal muscles of patients with COPD, determination of CAR is of possible therapeutic interest in this population. To the authors’ knowledge this is the first study to determine muscle CAR in patients with COPD and the influence of disease severity on CAR. Methods: Biopsy of m. vastus lateralis (right leg) of 40 patients with stable COPD (65±6 y; 75% male; 55.4±14.1 FEV1%pred; mMRC 1 (0-2) pt; CAT 15 (9-19) pt; BMI 25.9±4.7 kg/m²; 40% smokers; 79.0±11.2 6MWD%pred) and 20 age- and gender matched healthy controls (HC) (66±6 y; 75% male; 106.0±13.2 FEV1%pred; BMI 26.1±3.2 kg/m²; 0% smokers; 100.3±8.3 6MWD%pred) was obtained. CAR was measured by high-performance liquid chromatography and corrected for total protein content. Lung function, isometric quadriceps peak torque (QPT) and isokinetic quadriceps endurance (QE) corrected for leg lean mass, were also assessed. All outcomes were compared between patients in GOLD I&II, GOLD III&IV and HC. Results: GOLD III&IV patients (n=15) had lower CAR (14.13 (9.85-23.22) µmol/g) vs. HC (38.60 (23.50-54.23) µmol/g, P=0.003) and GOLD I&II patients (23.71 (19.23-38.97) µmol/g, P=0.053, n=25). No difference in QPT was found. Lower QE was present in GOLD III&IV patients (137.4±44.2 J/kg) vs. HC (172.0±36.2 J/kg) (P=0.025). Conclusion: Patients with severe to very severe COPD have lower muscle CAR compared to patients with mild to moderate COPD and HC.