RESUMO
Background: Major randomized clinical trials have shown that biological therapy can reduce the exacerbation rate and oral corticosteroid (OCS) dosage in patients with severe eosinophilic asthma. However, data on the continuation, efficacy, and safety of biological therapy in older patients with asthma are limited. Therefore, the aim of this study was to evaluate the differences in the continuation rate, efficacy, and safety of biological therapy between older (≥ 65 years) and younger (< 65 years) patients with asthma. Methods: In this single-center retrospective observational study, we collected clinical data of patients with asthma who were administered biological drugs such as omalizumab, mepolizumab, benralizumab, and dupilumab between April 2009 and August 2022. We comparatively analyzed the continuation, efficacy, and safety of biological therapy between older (age ≥ 65 years) and younger patient (age < 65 years) groups. The reasons for discontinuation or switching of biological drugs were also evaluated. Results: Sixty-two (31 older and 31 younger) patients were treated with 91 biologics during the observational period. The mean age of older patients was 74.3 ± 5.1 years and that of younger patients was 48.0 ± 14.0 years. The continuation rate of biological therapy was not significantly different between the groups. Social background was the most common reason for discontinuation of biological therapy in both groups, and insufficient effect was the most common reason for switching to biological drugs. Asthma exacerbations decreased in both groups within the first 12 months of biologic therapy. The dosage of OCS tended to decrease in the older group and significantly decrease in the younger group. Conclusion: Biologic therapy for older patients with asthma can be continued, with efficacy and safety similar to those in younger patients with asthma.
RESUMO
IAA, a major form of auxin, is biosynthesized from l-tryptophan via the indole-3-pyruvic acid (IPyA) pathway in Arabidopsis. Tryptophan aminotransferases (TAA1/TARs) catalyze the first step from l-tryptophan to IPyA. In rice, the importance of TAA/TARs or YUC homologs in auxin biosynthesis has been suggested, but the enzymatic activities and involvement of the intermediate IPyA in auxin biosynthesis remain elusive. In this study, we obtained biochemical evidence that the rice tryptophan aminotransferase OsTAR1 converts l-tryptophan to IPyA, and has a Km of 82.02 µM and a Vmax of 10.92 µM min-1 m-1, comparable with those in Arabidopsis. Next, we screened for an effective inhibitor of OsTAR1 from our previously reported inhibitor library for TAA1/TARs, designated pyruvamine (PVM). Differing from previous observations in Arabidopsis, hydroxy-type PVMs, e.g. PVM2031 (previous name KOK2031), had stronger inhibitory effects in rice than the methoxy-type. PVM2031 inhibited recombinant OsTAR1 in vitro. The Ki of PVM2031 was 276 nM. PVM2031 treatment of rice seedlings resulted in morphological changes in vivo, such as reduced lateral root density. Exogenous IAA rescued this growth inhibition, suggesting that the inhibitory effect is auxin specific. Furthermore, rice roots showed reduced IAA levels concomitant with reduced levels of IPyA in the presence of the inhibitors, suggesting that the IPyA pathway is an auxin biosynthesis pathway in rice. Since PVM2031 showed stronger inhibitory effects on rice auxin biosynthesis than known tryptophan aminotransferase inhibitors, we propose that the hydroxy-type PVM2031 is an effective tool for biochemical analysis of the function of auxin biosynthesis in rice roots.