Clinical evaluation of a nutraceutical diet as an adjuvant to pharmacological treatment in dogs affected by Keratoconjunctivitis sicca

Abstract

Background: Canine keratoconjunctivitis sicca (cKCS) is an inflammatory eye condition related to a deficiency in the tear aqueous fraction. Etiopathogenesis of such disease is substantially multifactorial, combining the individual genetic background with environmental factors that contribute to the process of immunological tolerance disruption and, as a consequence, to the emergence of autoimmunity disease. In this occurrence, it is of relevance the role of the physiological immune-dysregulation that results in immune-mediated processes at the basis of cKCS. Current therapies for this ocular disease rely on immunosuppressive treatments. Clinical response to treatment frequently varies from poor to good, depending on the clinical-pathological status of eyes at diagnosis and on individual response to therapy. In the light of the variability of clinical response to therapies, we evaluated the use of an anti-inflammatory/antioxidant nutraceutical diet with potential immune-modulating activity as a therapeutical adjuvant in cKCS pharmacological treatment. Such combination was administered to a cohort of dogs affected by cKCS in which the only immunosuppressive treatment resulted poorly responsive or ineffective in controlling the ocular symptoms.

Results: Fifty dogs of different breeds affected by immune-mediated cKCS were equally distributed and randomly assigned to receive either a standard diet (control, n = 25) or the nutraceutical diet (treatment group, n = 25) both combined with standard immunosuppressive therapy over a 60 days period. An overall significant improvement of all clinical parameters (tear production, conjunctival inflammation, corneal keratinization, corneal pigment density and mucus discharge) and the lack of food-related adverse reactions were observed in the treatment group (p < 0.0001).

Conclusions: Our results showed that the association of traditional immune-suppressive therapy with the antioxidant/anti-inflammatory properties of the nutraceutical diet resulted in a significant amelioration of clinical signs and symptoms in cKCS. The beneficial effects, likely due to the presence of supplemented nutraceuticals in the diet, appeared to specifically reduce the immune-mediated ocular symptoms in those cKCS-affected dogs that were poorly responsive or unresponsive to classical immunosuppressive drugs. These data suggest that metabolic changes could affect the immune response orchestration in a model of immune-mediated ocular disease, as represented by cKCS.

Keywords: Antioxidant and anti-inflammatory diet; Immune-mediated ocular disease; Keratoconjunctivitis sicca; Nutraceutical diet.

Fig. 1

Eyes improvement after 60-days treatment with 0,03 % Tacrolimus collyrium BID and 0,2 % Hyalistil eyewash plus the nutraceutical diet in ND group and with with 0,03 % Tacrolimus collyrium BID and 0,2 % Hyalistil eyewash plus the standard diet in SD group. a–c eye before treatment plus nutraceutical diet (time = 0), b–d eye at the end of treatment plus nutraceutical diet (time = 60). e–g eye before treatment plus standard diet (time = 0), f–h eye at the end of treatment plus standard diet (time = 60)

Fig. 2

a-b Mean conjunctival inflammation scores before and after 60 days treatment for ND and SD group, a significant decrease (****P < 0.0001) was observed in ND group at the end of the treatment; c–d mean corneal keratinization scores before and after 60 days treatment for ND and SD group, a significant decrease (****P < 0.0001) was observed in ND group at the end of the treatment; e–f mean corneal pigment density scores before and after 60 days treatment for ND and SD group, a significant decrease (****P < 0.0001) was observed in ND group at the end of the treatment; g–h mean mucus discharge scores before and after 60 days treatment for ND and SD group, a significant decrease (****P < 0.0001) was observed in ND group at the end of the treatment; i–l mean tear production (STT) in mm/min before and after 60 days treatment for ND and SD group, STT values resulted significantly increased (****P < 0.0001) in ND group at the end of treatment

Fig. 3

Graphical schematization of clinical symptoms score trends after 30 days since treatment suspension and after 30 days since treatment resumption. a Mean conjunctival inflammation scores before (T 60) and after 30 days nutraceutical diet suspension (T 90) for ND group and (b) after 30 days since nutraceutical diet resumption (T 120); c mean corneal keratinization scores before (T 60) and after 30 days nutraceutical diet suspension (T 90) for ND group and (d) after 30 days since nutraceutical diet resumption (T 120); e mean corneal pigment density scores before (T 60) and after 30 days nutraceutical diet suspension (T 90) for ND group and (f) after 30 days since nutraceutical diet resumption (T 120), scores resulted significantly increased (*P < 0.05); g mean mucus discharge scores before (T 60) and after 30 days nutraceutical diet suspension (T 90) for ND group and (h) after 30 days since nutraceutical diet resumption (T 120), scores resulted significantly increased (**P < 0.01); i mean tear production (STT) in mm/min before (T 60) and after 30 days nutraceutical diet suspension (T 90) for ND group and (l) after 30 days since nutraceutical diet resumption (T 120)