Alpha1-antitrypsin single dose adjuvant therapy for acute otitis media

Trauma-Induced Vestibular Dysfunction: Improved Repair Under Local Treatment With α1-Antitrypsin

AIM

To characterize vestibular recovery in a mouse model of unilateral labyrinthotomy under local AAT and dexamethasone treatment.

BACKGROUND

Alpha1-antitrypsin (AAT) is a circulating tissue-protective molecule that rises during inflammatory conditions and promotes inflammatory resolution. Its local concentration in human perilymph inversely correlates with the severity of inner ear dysfunction; concomitantly, mice that overexpress AAT and undergo inner ear trauma rapidly restore vestibular function. Locally applied AAT has yet to be examined in this context, nor has it been directly compared with anti-inflammatory corticosteroid treatment.

METHODS

Wild-type mice C57BL/6 underwent a unilateral inner ear injury. Nine microliters of saline, clinical-grade AAT (180 μg/site), dexamethasone (4 mg/site), or both were applied locally on Days 0, 1, and 2 (n = 5/group). Vestibular function was assessed for 7 days. An in vitro human epithelial gap closure assay was performed using A549 cells in the presence of AAT and/or dexamethasone.

RESULTS

Upon labyrinthotomy, all groups displayed severe vestibular dysfunction. Saline-treated mice showed the longest impairment. That group and the dexamethasone group displayed partial to no recovery, while AAT-treated mice exhibited complete recovery within 7 days; at this time point, dexamethasone-treated mice exhibited 50% recovery. Objective vestibular testing showed similar outcomes. In vitro, cotreatment with AAT and dexamethasone resulted in a gap closure dynamic that was superior to AAT alone at 6 h and superior to DEX alone at 48 h.

CONCLUSION

Locally applied AAT treatment is superior to locally applied dexamethasone in promoting vestibular recovery in vivo. Ongoing studies are exploring the potential advantages of AAT combined with early low-dose dexamethasone therapy.

Accelerated Wound Border Closure Using a Microemulsion Containing Non-Inhibitory Recombinant α1-Antitrypsin

Wound healing requires a non-compromising combination of inflammatory and anti-inflammatory processes. Human α1-antitrypsin (hAAT), a circulating glycoprotein that rises during acute-phase responses and during healthy pregnancies, is tissue-protective and tolerance-inducing; although anti-inflammatory, hAAT enhances revascularization. hAAT blocks tissue-degrading enzymes, including neutrophil elastase; it is, therefore, unclear how wound healing might improve under hAAT-rich conditions. Here, wound healing was examined in the presence of recombinant hAAT (hAAT^WT) and protease-inhibition-lacking hAAT (hAAT^CP). The impact of both hAAT forms was determined by an epithelial cell gap closure assay, and by excisional skin injuries via a microemulsion optimized for open wounds. Neutrophilic infiltration was examined after 8 h. According to results, both hAAT forms accelerated epithelial gap closure and excisional wound closure, particularly at early time points. Unlike dexamethasone-treated wounds, both resulted in closed borders at the 8-h time point. In untreated and hAAT^CP-treated wounds, leukocytic infiltrates were widespread, in hAAT^WT-treated wounds compartmentalized and in dexamethasone-treated wounds, scarce. Both hAAT forms decreased interleukin-1β and increased VEGF gene expression. In conclusion hAAT improves epithelial cell migration and outcomes of in vivo wounds irrespective of protease inhibition. While both forms of hAAT allow neutrophils to infiltrate, only native hAAT created discrete neutrophilic tissue clusters.