Use of GnRH Agonist in Dogs Affected with Leishmaniosis

SIMPLE SUMMARY: Most parasitic diseases, including Leishmania infection, often show more severe clinical signs in males than females. This is related to a different immune response, presumably related to testosterone activity. The present study aimed to evaluate the efficacy of a gonadotropin-releasing hormone GnRH agonist implant (deslorelin acetate) in association with meglumine antimoniate plus allopurinol in the treatment of dogs affected by Leishmania. Deslorelin acetate is a GnRH agonist, widely used for chemical reversible sterilization in male dogs, inducing testosterone suppression. Dogs treated with deslorelin show a significant decrease of clinical scores and serological test, suggesting a possible employ of GnRH agonist in the treatment of canine leishmaniosis. ABSTRACT: Sex-associated hormones such as testosterone have been demonstrated to modulate immune responses, which can result in different disease outcomes. The present study was aimed at evaluating the efficacy of a gonadotropin-releasing hormone GnRH agonist implant as deslorelin acetate in association with meglumine antimoniate plus allopurinol in dogs with canine leishmaniosis (CanL). Twenty-two dogs with CanL confirmed by clinical findings and laboratory tests were included in the study. Dogs were randomized into two groups. A control group (CTR, n = 12) was treated with meglumine antimoniate 50 mg/kg SC q 12 h for 28 days plus allopurinol at 10 mg/kg PO q 12 h for the whole study period (six months). An experimental group was treated with allopurinol and meglumine antimoniate, plus an implant of 4.7 mg deslorelin acetate (DES, n = 10). The animals were observed for three months, during which clinical evaluation, indirect fluorescent antibody test (IFAT) titre and testosterone assay were performed on time at day (D)0, 90 and 180. A significantly lower clinical score was recorded in DES than in CTR (p < 0.01) at D90 and D180 (p < 0.01). After 180 days of treatment (D180), a significant reduction of mean levels of IFAT was observed in the DES group (p = 0.03). A highly significant reduction of testosterone (p = 0.01) was observed in the DES group during the study. No statistical correlation between clinical scores, IFAT titres and testosterone within two groups was observed. Data suggested that the agonist of GnRH may be useful in the treatment of CanL.