5. Concluding Remarks
The induction of Trx1 is considered an effective compensatory protective mechanism by which to reduce or repair damaged tissue proteins. Studies have found that Trx1 exerts anti-inflammatory effects on a wide variety of inflammatory disorders. In this review, we summarised the available evidence on Trx1 and highlighted a variety of mechanisms underlying its beneficial effects against allergic inflammation. Trx1 also improves GC resistance; thus, it is a promising therapeutic target both as a supplement to existing treatments for allergic diseases and for patients with hormone intolerance. In addition, it has been reported that increased levels of Trx1 in plasma or serum are correlated with the progression of diseases, especially allergic asthma. Thus, Trx1 may also serve as a potential diagnostic marker as well as being useful for prognostic assessments.
A variety of protein expression systems, including yeasts, lactobacillus, algae and plants cells, have been developed with anti-allergic and anti-inflammatory activities that are comparable to those found for purified recombinant human thioredoxin (rhTrx); thus, feasible sources for production of thioredoxin protein currently exist. In future translational research focused on Trx1, it will be essential to conduct human studies. Importantly, clinical trials are now ongoing in which rhTrx1 is being administered to patients with atopic dermatitis and trans-tracheal inhalation experiment with rhTrx1 are being performed; Trx1 is showing good efficacy with no major side effects (unsubmitted data; Table 1). Finally, we suggest that Trx1 will be an important potential target for anti-allergic and anti-inflammatory drug development in the future (Figure 4b).