Establishing the Interrelations of the Laboratory Parameters in the Gut-Kidney Axis in Cats with Signs of Triple Phosphate Urolithiasis

Introduction. Efficient treatment of the feline urolithiasis much depends on the early diagnosis of the disease, however, the diagnostic algorithm of this type of pathology is extremely poor due to the various reasons, in particular, it does not take into account the interrelations in the gut-kidney axis. Analysis of the state of gastrointestinal tract functioning and the composition of the gut microbiota can improve the potential of diagnosing the urolithiasis, predict the risk, improve the prognosis and choose the correct treatment strategy. The aim of this publication is to establish the interrelations of the laboratory parameters in the gut-kidney axis in cats with struvite urolithiasis with the signs of cystolithiasis. Materials and Methods . The objects of the research were the outbred cats with the triple phosphate urolithiasis with the signs of cystolithiasis: 1st experimental group — females; 2nd experimental group — neutered males; the control group — clinically healthy animals of both sexes. The laboratory and clinical examinations of sick animals included: ultrasonography of abdominal organs; macroscopic and biochemical urine tests; microscopy of urine sediment and urine culture test without determination of antibiotic sensitivity; macroscopic, microscopic and simple chemical examinations of freshly excreted feces; bacteriological culture test of rectal flushes without determination of antibiotic sensitivity. Results . In the urine of cats of the experimental groups, under the activity of gram-negative microorganisms Escherichia coli (0.03±0.01×10 6 CFU (colony forming units) and 1.00±0.03×10 6 CFU) and gram-positive microorganisms Staphilococcus intermedius (1.05±0.07×10 6 CFU and 1.00±0.08×107 CFU) there were recorded within the microscope field of view: alkalization, development of hypersthenuria, proteinuria, hypercalciuria, hematuria, including microhematuria and leukocyturia, crystalluria. The results of coprological examinations in sick cats indicated the presence of stercobilin, well-digested muscle fibres, undigested and digested cellulose, extracellular and intracellular starch, as well as impurities of non-food origin (wool). The data of microbiological examinations of feces indicated the growth of Escherichia coli (1.00±0.05×10 5 CFU and 1.04±0.08×10 7 CFU). Along with the cystolytiasis, the acoustic shadowing of the gastrointestinal tract organs in the experimental animals revealed the hyperechogenicity of liver capsule and parenchyma and heterogeneity of the pattern. Discussion and Conclusion . The revealed character of the laboratory parameter changes in the experimental animals, such as the increase of protein and creatinine levels in urine and growth of Escherichia coli in feces, proved the existence of the pathogenetic relationship between the urogenital tract lesion caused by the gram-negative microorganisms and the gut microbiota in the gut-kidney axis. The results of our study of the sick animals’ urine indicated on the infection of the urogenital tract with the urease-producing microorganisms, which led to the alkalization of urine and formation of the infection struvite stones. Urolithiasis, in turn, had an impact on the gut microbiome due to the topographic proximity of the urogenital and gastrointestinal tracts: examination of feces in cats of the experimental group had confirmed the disorder of gastrointestinal tract functioning due to dysbiotic processes in the large intestine.