Secretory leucocyte protease inhibitor (SLPI) as an adjunct prognostic biomarker for canine pyometra

Pyometra is a potentially life-threatening condition that affects intact female dogs in their middle to advance age. Timely diagnosis and appropriate treatment are critical for the survival of patients, especially when pyometra advances to sepsis. This study aimed to investigate the prognostic potential of certain haematology, serum biochemical and inflammatory biomarker, secretory leucocyte protease inhibitor (SLPI) for pyometra in bitches (n = 41). Blood samples were collected after clinical diagnosis of pyometra for haematology and serum biochemistry. Based on the prognosis following medical/surgical treatment, animals were retrospectively categorized into survivor (n = 29) and dead (n = 12). Endometrial tissue sections were obtained from the bitches undergoing ovariohysterectomy (n = 21). Serum concentration of SLPI was quantified using sandwich ELISA and its expression in the endometrium was investigated using RT-qPCR. A marked increase in the total leucocyte count (TLC), neutrophils, blood urea nitrogen (BUN) and serum creatinine was observed in the female dogs that did not survive. Significant elevation in the serum SLPI concentration (3.49 ± 0.44 vs. 2.38 ± 0.13 ng/mL) was observed in the bitches those died after the treatment, in comparison to those survived (p < .01). Additionally, there was a notable upregulation of SLPI in the endometrium in the bitches those died due to pyometra. Based on the ROC analysis results, it was observed that a cut-off concentration of 2.93 ng/mL for SLPI, 27.77 mg/dL for BUN and 16.3 × 10³ /μL for TLC could effectively distinguish the prognosis of pyometra-affected dogs. From this study, it can be concluded that upregulation of SLPI in the endometrium and its elevated concentration in peripheral circulation along with TLC and BUN concentration could serve as valuable indicators for predicting the prognosis of pyometra in bitches.