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The potential ergogenic effects of asthma medication in athletes have been controversially discussed for decades. The prevalence of asthma is higher in elite athletes than in the general population. The highest risk for developing asthmatic symptoms is found in endurance athletes and swimmers. In addition, asthma seems to be more common in winter-sport athletes. Asthmatic athletes commonly use inhaled beta2-agonists to prevent and treat asthmatic symptoms. However, beta2-agonists are prohibited according to the "Prohibited List of the World Anti-Doping Agency" (WADA). Until the end of 2009 an exception was only allowed for the substances formoterol, salbutamol, salmeterol, and terbutaline by inhalation, as long as a so-called therapeutic use exemption has been applied for and was granted by the relevant anti-doping authorities. From 2010 salbutamol and salmeterol are allowed by inhalation requiring a so called declaration of use., (Copyright 2010 Elsevier Inc. All rights reserved.)

Objectives: Therapeutic augmentation of collateral artery growth (ie, arteriogenesis) is of particular clinical interest for improving blood flow in vascular occlusive disease. Quantification of collateralization in small animal models is difficult, however, and the commonly used technique of laser Doppler perfusion imaging (LDPI) has always been criticized. Therefore, a new method, termed indocyanine green angiography (ICGA), was established for in vivo imaging of arteriogenesis in mice and compared with LDPI., Method: Using the accepted model of ligation of the left femoral artery of 45 C57BL6 mice, we determined arteriogenesis both by LDPI and ICGA, which were applied before and periodically after ligation of the left femoral artery (each group n = 7). Collateral artery growth within the hind limb was additionally verified by histologic workup., Results: Determination of flow by ICGA, as represented by maximal pixel intensity (ratio of left/right hind limb) demonstrated a drop from 0.97 +/- 0.06 before ligation to 0.11 +/- 0.12 directly after ligation, which recovered to 0.48 +/- 0.22 after 1 week, to 0.65 +/- 0.11 after 2 weeks, and to 0.59 +/- 0.22 after 3 weeks (n = 7, P < .05). Similarly, flow determined as the perfusion index (slope of pixel intensity, ratio left/right) dropped from 1.18 +/- 0.4 before ligation to 0.02 +/- 0.03 immediately after ligation but recovered to 0.08 +/- 0.01 after 1 week, to 0.17 +/- 0.01 after 2 weeks, and to 0.17 +/- 0.06 after 3 weeks (n = 7, P < .05). Quantification by LDPI demonstrated a drop from 1.06 +/- 0.06 (left/right ratio) before ligation to 0.37 +/- 0.03 immediately after ligation. In contrast to ICGA, perfusion recuperated completely within 1 week to 1.01 +/- 0.14 and tended to be even higher in the ligated than in the unligated hind limb after 2 (1.09 +/- 0.25) and 3 weeks (1.20 +/- 0.29), pointing towards limitations of this technique. Histologic analysis confirmed the significant increase in the number of collaterals. The intraindividual ratio increased from 1.0 +/- 0.05 before ligation to 1.35 +/- 0.10 at 2 weeks and 1.41 +/- 0.08 at 3 weeks after ligation (P < .05)., Conclusion: Our data demonstrate that ICGA represents a potent tool for the quantification of collateral flow in small animal models. The current standard of LDPI seems to rather represent blood movements within the superficial skin but not of the entire hind limb.