Nanoparticulate CpG Immunotherapy in RAO‐Affected Horses: Phase I and IIa Study

Abstract

BackgroundRecurrent airway obstruction (RAO), an asthma‐like disease, is 1 of the most common allergic diseases in horses in the northern hemisphere. Hypersensitivity reactions to environmental antigens cause an allergic inflammatory response in the equine airways. Cytosine‐phosphate‐guanosine‐oligodeoxynucleotides (CpG‐ODN) are known to direct the immune system toward a Th1‐pathway, and away from the pro‐allergic Th2‐line (Th2/Th1‐shift). Gelatin nanoparticles (GNPs) are biocompatible and biodegradable immunological inert drug delivery systems that protect CpG‐ODN against nuclease degeneration. Preliminary studies on the inhalation of GNP‐bound CpG‐ODN in RAO‐affected horses have shown promising results.ObjectivesThe aim of this study was to evaluate the clinical and immunological effects of GNP‐bound CpG‐ODN in a double‐blinded, placebo‐controlled, prospective, randomized clinical trial and to verify a sustained effect post‐treatment.Animals and MethodsTwenty‐four RAO‐affected horses received 1 inhalation every 2 days for 5 consecutive administrations. Horses were examined for clinical, endoscopic, cytological, and blood biochemical variables before the inhalation regimen (I), immediately afterwards (II), and 4 weeks post‐treatment (III).ResultsAt time points I and II, administration of treatment rather than placebo corresponded to a statistically significant decrease in respiratory effort, nasal discharge, tracheal secretion, and viscosity, AaDO 2 and neutrophil percentage, and an increase in arterial oxygen pressure.Conclusion and Clinical ImportanceAdministration of a GNP‐bound CpG‐ODN formulation caused a potent and persistent effect on allergic and inflammatory‐induced clinical variables in RAO‐affected horses. This treatment, therefore, provides an innovative, promising, and well‐tolerated strategy beyond conventional symptomatic long‐term therapy and could serve as a model for asthma treatment in humans.

A comparison of nanoparticulate CpG immunotherapy with and without allergens in spontaneously equine asthma‐affected horses, an animal model

“…In contrast, an in‐vivo study showed a significant increase of IL‐10 in the BAL of equine asthma horses after five inhalations of CpG‐ODN 7. Regardless of the IL‐10 concentrations, inhalation of CpG‐ODN can achieve a persistent improvement of clinical signs in horses with equine asthma as shown in this study and former studies 7, 8.…”

“…The biodegradable gelatin nanoparticles are well tolerated, immunologically inert, stable for inhalation, and a successful drug delivery system 7, 8, 20.…”

“…The clinical examination was conducted as previously reported 7, 8 and in accordance with established and standardized scoring systems 2, 14, 15, where available. The variables examined included the measurement of the following: breathing rate at rest, breathing type (relative units [RU] in the range of 0–4; where 0 = no or little movement in the ventral region of the flank, and 4 = obvious abdominal lift, heave line and nostril flaring) 14, nasal discharge (RU in the range of 0–3; 0 = none, 1 = mild, 2 = moderate, and 3 = severe discharge), auscultation of lungs and trachea (in the range of RU 0–4; 0 = physiological, 1 = mild, 2 = moderate, 3 = severe, 4 = wheezes/rhonchi) 2, 7, 8, and arterial blood gas parameters 15.…”

Inflammatory Airway Disease of Horses—Revised Consensus Statement

“…More recently, inhaled nanoparticles of cytosine–phosphate–guanosine oligonucleotides (CpG), which induce a Th2/Th1‐shift, have been shown to decrease neutrophil percentages in TW and mucus secretions observed in the trachea, as well as improve lung function and clinical signs of horses with RAO 125. The relevance to IAD is unknown.…”

Preliminary evaluation of cytosine‐phosphate‐guanine oligodeoxynucleotides bound to gelatine nanoparticles as immunotherapy for canine atopic dermatitis

“…Unloaded GNPs do not show immunostimulatory activity (Zwiorek and others 2008). Repeated inhalation of an aerosol formulation of GNP-bound CpG ODN (CpG GNP) increased IL-10 and interferon (IFN)-γ expression, but also reduced clinical parameters of allergic inflammation in horses with recurrent airway obstruction (Klier and others 2012, Klier and others 2015). The CpG GNP used in this study increased secretion of IL-10 in vitro in peripheral blood mononuclear cells (PBMCs) obtained from atopic dogs (Rostaher-Prélaud and others 2013).…”