Serum symmetric dimethylarginine concentration in healthy horses and horses with acute kidney injury.

BACKGROUND: There are limited options to diagnose acute kidney injury (AKI) in horses. Symmetric dimethylarginine (SDMA) is routinely used in human and small animal medicine. The aim of this study was to assess serum SDMA concentrations in healthy horses and horses with AKI. The objective of this study was to evaluate the association of: 1) age, 2) sex, 3) body weight and 4) serum creatinine and urea levels on serum SDMA concentrations. Fifty-three healthy horses, including 17 foals (2-6 months of age) and 36 adult horses (3-29 years of age), and 23 horses with AKI were included in the study based on history, physical examination, blood analysis, urinalysis and an ultrasonographic examination of the urinary tract. Serum SDMA concentrations were measured using a non-species specific commercial ELISA test. RESULTS: In healthy adult horses, the value of SDMA was 0.53 ± 0.14 µmol/L. The value was higher in foals (1.5 ± 0.4 µmol/L, P < 0.001). Horses with AKI had significantly higher concentrations of SDMA compared to healthy horses (1.76 ± 1.05 µmol/L, P < 0.001). In the healthy adult horses, there was no association of sex, age or body weight on SDMA. However, a significant positive relationship was found between serum creatinine and SDMA concentrations. CONCLUSIONS: Healthy adult horses had SDMA values similar to those of other species. Foals had higher SDMA values. Therefore, different reference values should be created for them. The study confirmed an increased SDMA in horses with AKI. This, as well as the low influence of extrarenal factors on the SDMA values, may confirm its usefulness in the diagnosis of kidney dysfunction. Higher SDMA values may also indicate a more advanced degree of kidney dysfunction. Further research is required to determine whether SDMA could be used to detect kidney dysfunction in the asymptomatic stage of AKI.

Two-dimensional echocardiographic measurements of the right coronary artery in healthy horses - a pilot study.

BACKGROUND: Precise understanding of the dimensions of the vascular lumina is essential for accurate interpretation of cardiac vessels imaging. To the authors' best knowledge, this is the first study focusing on the ultrasound measurement of the right coronary artery (RCA) in the horse. The aim of this study was to determine both the ultrasonographic range of the normal diameter and lumen area of the RCA in horses and the influence of gender, age and level of training on the RCA dimensions. An additional aim of the study was to assess intra- and inter-observer repeatability of the collected measurements. METHODS: Thirty-six privately owned, healthy horses were included in the study. The internal lumen diameter and the area of the RCA were measured in the right parasternal long axis view in the 3rd intercostal space during systole and diastole. The results were compared between groups using the analysis of variance (ANOVA) and Student's t-test. The correlation between the physiological parameters and the RCA was assessed using Pearson correlation coefficient. Student's t-test was used to compare the results obtained by two researchers and from two scanners. RESULTS: The mean diameter of the RCA was 13.1 ± 1.5 mm in systole and 11.5 ± 1.3 mm in diastole, and the mean area was 1.3 ± 0.2 cm2 and 1.1 ± 0.2 cm2, respectively. There were no statistically significant measurement differences between geldings and mares. A positive correlation between body weight and RCA dimensions as well as height and RCA dimensions were seen. There was a negative correlation between the age and the RCA area. A statistically significant difference in the RCA area was seen between race and retired horses. Intra- and inter-observer agreement was strong with a few statistically significant differences. CONCLUSIONS: The age, size, and level of training may affect the ultrasound measurement of the RCA in horses. Non-invasive transthoracic echocardiography may be used to assess the size of the right coronary vessel in various types of horses.

Fatal pulmonary hemorrhage in a horse during bronchoalveolar lavage - single case report.

BACKGROUND: Pulmonary hemorrhage is a rare cause of death in horses. Hemorrhage within the respiratory tract has many causes, including mycosis of the guttural pouch, invasive procedures causing serious trauma to nasal conchae, or lung biopsy. We report on a rare case of a fatal pulmonary hemorrhage in a horse after a severe cough during bronchoalveolar lavage. To the best of our knowledge, this is the first report of spontaneous hemorrhage in a horse during bronchoalveolar lavage. CASE PRESENTATION: A 21-year-old mare which belonged to the didactic herd of The Faculty of Veterinary Medicine underwent BAL procedure for training purposes. Clinical examination prior to the procedure did not reveal any abnormalities and the horse had been classified as healthy. The horse was sedated with 0.01 mg/kg of detomidine and 0.01 mg/kg of butorphanol. The silicon BAL catheter was passed through the nasal passage into the trachea and then into the bronchus. Before catheter was wedged, the mare began to cough heavily and massive haemorrhage from mouth and nostrils occurred. Despite fluid therapy, shock occurred within 15 min and the mare was euthanized. Upon necropsy, site of hemorrhage was identified in the left lobar caudal bronchi, from a large blood vessel running directly beneath the bronchial wall. Upon histology, a chronic lympho-plasmocytic inflammatory process in left bronchi was identified. Moreover, Masson's trichrome staining revealed severe, perivascular fibrosis. CONCLUSION: Although BAL is a relatively safe procedure, and such complications should be treated as extremely rare, this case indicates that, in some individuals with specific subclinical problems, even mild physical force such as a cough can lead to rupture of the artery.

Evaluation of Tryptic Podocin Peptide in Urine Sediment Using LC-MS-MRM Method as a Potential Biomarker of Glomerular Injury in Dogs with Clinical Signs of Renal and Cardiac Disorders.

The early asymptomatic stage of glomerular injury is a diagnostic challenge in the course of renal and extra-renal disease, e.g., heart insufficiency. It was found that podocin, a podocyte-specific protein present in the urine, may serve as a biomarker in the diagnosis of glomerular disease in humans and animals including glomerulonephritis, glomerulosclerosis, amyloidosis, or nephropathy. Therefore, there is a need of development of the sensitive and straightforward method of urinary podocin identification. In this work, we report our extended research under the glomerular injury investigation in dogs by application of clinical examination and LC-MS-MRM method in the identification of canine podocin in urine samples. The LC-MS-MRM method is based on the identification of podocin tryptic peptide with the 218H-AAEILAATPAAVQLR-OH232 sequence. The model peptide was characterized by the highest ionization efficiency of all the proposed model podocin tryptic peptides in a canine urine sediment according to the LC-MS/MS analysis. The obtained results revealed the presence of the model peptide in 40.9% of dogs with MMVD (active glomerular injury secondary to heart disease = cardiorenal syndrome-CRS) and 33.3% dogs with chronic kidney disease. The potential applicability of the developed methodology in the analysis of podocin in canine urine sediments was confirmed.

ECEIM consensus statement on equine kidney disease.

The aim of this consensus statement is to summarize and appraise scientific evidence and combine this with the clinical experience of a panel of experts to optimize recommendations on how to recognize and manage kidney disease in horses.

A case of non-mosaic X trisomy (65,XXX) in a Thoroughbred mare confirmed by cytogenetic and molecular analysis.

A 9-year-old Thoroughbred mare with normal external genitalia and regular oestrus symptoms was gynecologically examined prior to insemination. This primary examination revealed the presence of a hypoplastic uterus and the lack of normal ovaries, and the mare was therefore subjected to more detailed diagnostics, including endocrinological, genetic, and clinical tests. Diagnostic imaging with the use of ultrasonography and endoscopy confirmed the underdevelopment of internal genitalia. Analysis of circulating sex hormones revealed very low concentrations of progesterone and oestradiol. Finally, cytogenetic analysis showed the presence of non-mosaic X trisomy (65,XXX), an aneuploidy of sex chromosomes that is rarely detected in horses. This finding was also confirmed by molecular methods, including highly sensitive droplet digital PCR (ddPCR) and microsatellite markers genotyping. Our study reveals the need for gynaecological and genetic evaluation of broodmares, even if their phenotype (including developed external genitalia and oestrus symptoms) shows no signs of potential abnormalities.

Reproducibility of the body condition score assessment in Silesian horses, using the 9-point BCS scale.

Control of body condition is an important aspect of horse management. Its correct evaluation, and the possibility of using universal indicators are of key importance for preserving the animals' wellbeing and for providing them with proper care. The objective of this study was to evaluate the agreement between body condition scores assessed by teams and individuals, using the 9-point Body Condition Score scale created by Henneke. The evaluation of a herd of 49 healthy adult Silesian horses was conducted by veterinary medicine students with adequate training in body condition assessment. Group assessments made by each of two teams and then assessments made by two individuals were compared to determine the repeatability of the results. While significant differences were found between the assessments made by the individuals, there were no significant differences between assessments made by the teams or between the individuals and the teams. The results are indicative of the method's repeatability.

Biomarkers of Kidney Disease in Horses: A Review of the Current Literature.

Creatinine only allows detection of kidney disease when 60 to 75% of the glomerular function is lost and is therefore not an ideal marker of disease. Additional biomarkers could be beneficial to assess kidney function and disease. The objectives are to describe new equine kidney biomarkers. This systematic review assesses the available literature, including the validation process and reference values, following which the authors suggest recommendations for clinical use. SDMA may have some potential as equine kidney biomarker, but there is currently a lack of evidence that SDMA offers any advantage compared to creatinine in detecting Acute Kidney Injury (AKI). Cystatin C and podocin show potential as biomarkers for kidney disease (including detecting AKI earlier than creatinine) and should be studied further. NGAL has potential as a biomarker of kidney disease (including detecting AKI earlier than creatinine), and potential as an inflammatory marker. Literature on MMP-9 does not allow for conclusive statements about its potential as a biomarker for kidney disease. The future may show that NAG has potential. For all biomarkers, at this stage, available scientific information is limited or too scarce to support clinical use, and only SDMA can be measured for clinical purposes. In conclusion, there are multiple new biomarkers with the potential to diagnose kidney problems. However, there are only a few studies available and more data is needed before these biomarkers can be applied and recommended in our daily practice.

Influence of Obesity on Histological Tissue Structure of the Cardiovascular System in Horses.

It has been well established that obesity in horses can have a negative impact on their health, including endocrine disturbances. In humans, it is well known that obesity leads to structural and functional changes of the cardiovascular system. The aim of the study was to assess the impact of obesity on the histological structure of the myocardial tissue, as well as great and peripheral arteries in horses. The heart, arteries (aorta, pulmonary artery and palmar arteries) specimens from 7 horses with normal BCS (4-5/9) and 12 extremely obese (BCS 9/9) draft slaughter horses were obtained for histopathological evaluation. The heart tissue and great arteries showed more intense disturbances in the architecture and vacuolization in the aorta in obese horses as compared to the healthy group. The intima in the pulmonary artery, coronary arteries and palmar arteries was thicker in the obese, rather than healthy horses. The palmar arteries in obese horses had a larger lumen diameter and the lumen-to-total diameter ratio as compared to the control group. The presented study showed a significant effect of obesity on the heart as well as the central and peripheral vessels in horses. This forms the basis for a deeper reflection on the impact of obesity on the equine body.

Retrospective Evaluation of the Most Frequently Observed Histological Changes in Duodenal and Rectal Mucosal Biopsies in Horses with Recurrent Colic.

Colic, a condition affecting the gastrointestinal tract of horses, manifests as severe pain and may be a life-threatening condition. It is possible to distinguish between an acute, disposable process, as well as recurrent colic symptoms (abdominal pain) caused by an ongoing chronic inflammatory process. This paper presents a retrospective analysis of the histopathological findings of duodenal and rectal samples taken from horses with recurrent colic, with the aim to determine the frequency and extent of inflammation. The samples, i.e., duodenal biopsy (60 samples) and rectal biopsy (17 samples), were taken from 77 horses showing recurrent colic symptoms. Histopathological examination included staining with hematoxylin and eosin. The examination included evaluation of the superficial epithelium, mucosal lamina propria, and submucosa. All samples from the duodenum and rectum showed the presence of leukocyte infiltration in the mucosal lamina propria. The most frequently observed cellular infiltration was a moderate infiltration consisting of lymphocytes and plasma cells in duodenum and mixed populations of plasma cells, lymphocytes, and eosinophilia in the rectum. Mott cells were also noted among the inflammatory infiltrates. More than one-fourth of the horses were found to have shortened intestinal villi. The results presented here showed the involvement of inflammation in the course of recurrent colic, which can be both its cause (by impairing motility and absorption) and its effect (as a result of obstruction or ischemia).

Aerobic Commensal Conjunctival Microflora in Healthy Donkeys.

From a clinical point of view, knowledge of the commensal microbial flora of the conjunctival sac in healthy individuals proves to be of great importance. The aim of this study was to assess the presence and the composition of normal ocular microflora of healthy donkeys. Fourteen clinically healthy donkeys (Equus asinus) participated in the study. After prior ophthalmological examination, which showed no abnormalities, a conjunctival swab was taken from each donkey from the right and left eye. Species-specific identification was based on a morphological assessment of bacterial colonies stained with the Gram technique, as well as on biochemical properties and the disk-diffusion method. Around 82% of samples were positive for bacteria cultivation; Pantoea agglomerans was the most prevalently detected species, followed by Moraxella lacunata. In conclusion, our study made it possible to determine the commensal flora of the conjunctival sac in donkeys. The obtained results also showed discrepancies in the composition of the conjunctival sac flora of donkeys and horses, despite the geographical proximity of performed studies. Knowledge of the commensal conjunctival flora of donkeys is of great clinical importance due to their greater exposure to corneal damage and infections than horses.

Homeostasis of the Intestinal Mucosa in Healthy Horses-Correlation between the Fecal Microbiome, Secretory Immunoglobulin A and Fecal Egg Count.

The defensive function of the intestinal mucosa depends both on the ability to secrete immunoglobulin A and communication with the mucus microbiome. In horses, the functioning of this system is also influenced by the presence of nematode eggs. Feces collected from healthy horses were examined to determine the fecal egg count, immunoglobulin A level (ELISA), microbiome composition (Next-Generation Sequencing, NGS, V3−V4 and V7−V9 hypervariable regions of the 16S rRNA gene analysis and short-chain fatty acid (SCFA) production ((high-performance liquid chromatography, HPLC). In the taxonomic analysis within the phylum, the following order of dominance was found: Firmicutes, Bacteroidota, Verrucomicrobiota and Fibrobacterota. The coefficient of phylogenetic diversity of the microbiome positively correlated with both secretory immunoglobulin A (SIgA) [µg/g of feces] (p = 0.0354, r = 0.61) and SIgA [µg/mg of fecal protein] (p = 0.0382, r = 0.6) and with the number of Cyathostomum eggs (p = 0.0023, r = 0.79). Important components of the key microbiome in horses, such as phylum Proteobacteria and species Ruminococcus flavefaciens, were positively correlated with the fecal SIgA (p < 0.05). All the obtained results indicate the existence of significant relationships between the host response (SIgA production) and composition and SCFA production in the microbiome as well as the presence of small strongyles in the digestive tract of horses.

The Differences in Histoarchitecture of Hoof Lamellae between Obese and Lean Draft Horses.

Obesity is a common problem in horses. The associations between obesity and equine metabolic syndrome (EMS) and between EMS and laminitis are known. However, there is a lack of data on whether obesity itself can affect hoof lamellae. Forelimbs and blood from 12 draft horses (six obese and six lean) from a slaughterhouse were acquired. To exclude laminitis and EMS horses, insulin concentration was measured, and hooves were radiographed. Histological evaluation was performed. The shape of the primary and secondary epidermal lamellae (PEL and SEL) was evaluated, and the length of the keratinized and total primary epidermal lamellae was measured (KPEL and TEL). All horses showed pathological changes in lamellae. In the lean group, the changes were longer SELs, more proliferated and separated PDLs, and less standard PDLs. In the obese group, the changes were a lower number of club-shaped and standard SELs and significantly more tapered SELs. No difference in the shape of PELs and the length of KPELs was noticed. The research did not confirm the effects of obesity on lamellar failure. The measurements taken indicate that the lamellae are much longer compared to other research studies; this could indicate that the length of the PEL depends on the hoof size.

Evaluation of Serum and Urine Neutrophil Gelatinase-associated Lipocalin and Cystatin C as Biomarkers of Acute Kidney Injury in Horses.

INTRODUCTION: Diagnosis of acute kidney injury (AKI) in horses is difficult at the subclinical stage, due to nonspecific clinical signs. The aim of this study was to evaluate the concentrations of selected serum and urinary biomarkers in healthy horses, horses at risk of AKI, and those with clinical AKI. MATERIAL AND METHODS: Thirty healthy horses, 30 horses at risk of AKI and 11 horses with clinical AKI and azotaemia were included in the study. Serum and urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were measured using commercially available enzyme immunoassay tests. RESULTS: The median and (in parentheses) first and third quartile concentrations of selected biomarkers in healthy horses, horses at risk of AKI and horses with AKI were respectively as follows: serum cystatin C - 0.25 (0.19-0.37), 0.23 (0.15-0.37) and 0.61 (0.37-1.13) mg/L; serum NGAL - 50.5 (38.8-58.8), 51.1 (40.4-66.9) and 98.1 (59.4-128.2) ng/mL; urinary NGAL - 20.7 (17.9-24.5), 32.3 (32.7-55.8) and 36.6 (26.8-89.9) ng/mL; and urinary cystatin C - 0.1 (0.07-0.13), 0.13 (0.1-0.2) and 0.34 (0.22-0.37) mg/L. There were significant differences in the concentration of all biomarkers between the healthy and AKI-affected horses. CONCLUSION: Horses with AKI all had biomarker concentrations higher than the healthy horses. None of the biomarkers made azotaemia recognisable in all affected horses. The obtained results indicate the need to create a serum and urinary biomarker panel to detect AKI.

Renal Resistive Index as A Potential Indicator of Acute Kidney Injury in Horses.

Reliable and simple tests are constantly being sought to enable the quick detection of acute kidney injury in humans and animals. Diagnosis of subclinical AKI in horses, mainly in field practice, is difficult. An ultrasound scan is a routine test performed when kidney disease is suspected. The aim of the study was to establish the value of the renal resistive index (RRI) in intrarenal arteries in horses with clinical AKI and compare it to that of healthy horses. The second goal was to determine whether potentially nephrotoxic agents can influence RRI. The kidney ultrasonography examination was performed in 30 healthy horses, 11 horses with AKI and 30 horses at risk for AKI (10 colic horses, 10 horses receiving gentamicin and 10 horses receiving NSAIDs). RRI values were measured using pulsed-wave Doppler. Differences in RRI between groups were observed only in the right kidney. Horses with AKI had significantly higher RRI values compared to healthy horses. In the risk group, there was no effect of potentially nephrotoxic agents on the RRI value. RRI value in horses seem to be lower than in other species. The increase in this parameter in horses with AKI affected only one kidney and these values did not reach values obtained in other species. The clinical application of this method in non-cooperating animals remains questionable, and therefore RRI Doppler ultrasonography of blood flow in the intrarenal arteries may have poor clinical utility as a diagnostic tool in the diagnosis of AKI in horses.

Measurement of Selected Renal Biochemical Parameters in Healthy Adult Donkeys Considering the Influence of Gender, Age and Blood Freezing.

The reference values of the serum and urine biochemical parameters have not been well-studied in donkeys. This study aimed to assess the normal values of the selected renal biomarkers, such as: serum creatinine, blood urea nitrogen (BUN), albumin, total protein (TP), electrolytes and symmetric dimethylarginine (SDMA), urine protein concentration (UPC), urine protein/creatinine ratio (UPCR), the urine gamma-glutamyl transferase (GGTP)-to-creatinine ratio, serum creatinine-to-urine creatinine ratio (sCr/uCr), serum BUN-to-serum creatinine ratio (sBUN/sCr) and UPC-to-TP ratio, as well as the fractional electrolyte excretion of sodium (FENa) and potassium (FEK) in donkeys. The effects of age, gender and deep freezing of the serum material were investigated. Sixty-five healthy adult donkeys were involved in this study. The results showed higher BUN and TP values and lower albumin, UPCR, FENa and FEK levels in donkeys when compared to the reference values in horses. A significant gender relationship for creatinine and BUN was found. Age influenced the values of albumin, TP, potassium and chlorine. Potassium, sodium and SDMA did not show significant concentration changes after freezing. The study results demonstrated that horse reference range values for some parameters cannot be applied to donkey samples. Only a few of the serum parameters were not affected by freezing, and this should be taken into account when storing biological materials.

Detecting acute kidney injury in horses by measuring the concentration of symmetric dimethylarginine in serum.

BACKGROUND: Acute kidney injury (AKI) in horses may develop as a complication of a primary disease or following the administration of nephrotoxic drugs, and may pose a diagnostic challenge. Hence, the main objective of this study was to evaluate the concentrations and diagnostic significance of serum symmetric dimethylarginine (SDMA) and conventional renal dysfunction biomarkers in healthy horses, horses at risk of developing AKI, and horses with clinically evident AKI. A second aim was to assess how gastrointestinal disease and exposure to potentially nephrotoxic drugs affected SDMA levels. Thirty healthy horses, 30 horses with gastrointestinal disease and/or receiving phenylbutazone or gentamicin (risk group) and 11 horses with AKI were included in the study. Serum SDMA levels were measured using commercially available enzyme immunoassay tests. RESULTS: SDMA levels in healthy horses, horses at risk of AKI and horses with AKI were 12 µg/dL (11-14), 12 µg/dL (11-13) and 20 µg/dL (20-37), respectively (all results presented as a median (quartile 1-quartile 3)). There was a significant difference in SDMA concentration between the healthy horses and those with AKI, whereas the SDMA levels in healthy horses and those at risk of AKI were comparable. A SDMA cut-off value of 19 µg/dL was established. Horses from the risk group had higher urine protein concentration and urine protein to creatinine ratio compared with healthy horses. Furthermore, horses with colic from the risk group presented with elevated urine γ-glutamyl transpeptidase to creatinine ratio. CONCLUSION: The SDMA cut-off value established in healthy horses was higher than previously reported. The SDMA level correlated with the azotaemia levels. Horses from the AKI risk group had normal SDMA levels but single urine parameters was abnormal indicating their higher sensitivity in assessing subclinical kidney dysfunction.

Evaluation of the diagnostic value of the renal resistive index as a marker of the subclinical development of cardiorenal syndrome in MMVD dogs.

INTRODUCTION: Myxomatous mitral valve disease (MMVD) in dogs inevitably causes renal dysfunction. These interactions are known as the cardiorenal syndrome (CRS). The main aims of the study were to evaluate whether renal resistive index (RRI) may be useful as a non-invasive marker in subclinical stage of kidney injury in dogs with MMVD and to compare RRI with SDMA and Cyst C. METHODS: Forty-four dogs were divided into two groups: control-15 healthy dogs and the heart group-29 dogs with MMVD (ACVIM class Cc). Study protocol included: anamnesis, clinical examination, electrocardiography, echocardiography, chest radiography, abdominal ultrasonography with measurements of the renal resistive index (RRI), urine, and blood analysis. RESULTS: The RRI in the heart group was significantly higher 0.725 ± 0.035 versus control group 0.665 ± 0.028 (p < 0.00085). The RRI cut-off point in dogs with stable chronic heart failure (CHF) under 8 years is 0.775, in older 0.64. RRI was similar in MMVD dogs treated with ACE-I + furosemide and dogs treated ACE-I + torasemide + pimobendan + spironolactone. There was no correlation between RRI and SDMA or Cyst C. CONCLUSION: RRI is more sensitive than creatinine, SDMA and Cyst C to reveal kidney injury in MMVD dogs class Cc younger than 8 years.

The examination of biophysical parameters of the skin in Polish Konik horses.

This study aimed to assess the biophysical parameters of the skin in Polish Konik horses (Polish primitive horses). According to the authors, this is the first assessment performed on such a wide scale in this group of animals. The evaluation carried out is innovative both with regards to the breed of the animals and the wide scope of the physicochemical skin assessment. The study group comprised mares, stallions and geldings, and the evaluations concerned transepidermal water loss, corneometry, pH, skin temperature assessment and mexametry. These parameters were assessed in five skin regions: the lips, the right ear, the prosternum, the right side of the neck and the chest. The measurements were taken after spreading the hair apart, with the use of a Multiprobe Adapter System (MPA®) and dedicated probes (Courage + Khazaka electronic GmbH, Cologne, Germany). The measurements revealed statistically significant differences in the values of transepidermal water loss in the lips in mares compared with stallions (P = 0.023) and also in stallions compared with geldings (P = 0.009). Corneometry showed significantly higher results in the neck region in mares compared with stallions (P = 0.037) and the prosternum areas in mares and geldings compared with stallions (P = 0.037 and P = 0.018). Skin pH measurement on the right side of the neck rendered significantly higher values in stallions than in mares (P = 0.037). In geldings, the skin temperature was significantly higher than in stallions (P = 0.049). Once the appropriate physicochemical values for specific animal species and breeds are determined, non-invasive methods of skin examination in many diseases and also methods of evaluation of the efficacy and/or adverse effects of applied medications can be established.

Evaluation of podocin in urine in horses using qualitative and quantitative methods.

No sensitive method for diagnosing early kidney dysfunction in horses has been identified so far. Many studies carried out in humans and small animals show that podocin can be useful to diagnose various kidney diseases, mainly affecting the glomeruli. The aim of this study was to perform a qualitative and quantitative analysis of podocin in urine samples obtained from healthy horses, horses with clinical kidney dysfunction and horses at risk of acute kidney injury. The study objectives aimed to assess: (1) whether the selected podocin tryptic peptide for LC-MS-MRM allows for podocin detection in horse; and (2) whether the species-specific ELISA test makes this detection possible as well;, (3) whether the chosen methods are sensitive enough to detect kidney dysfunction and glomerular injury, (4) whether the results of the tests applying both methods correspond with one another, (5) whether the results correlate with the hematological and biochemical data. The signals that may indicate the presence of trypsin fragments of podocin were found in three healthy horses, all the horses diagnosed with kidney dysfunction and half of the animals at risk for acute kidney injury. The concentration of podocin, diagnosed with the ELISA test was as follows: from 0.19 to 1.2 ng/ml in healthy animals, from 0.19 to 20.0 ng/ml in AKI horses, from 0.29 to 5.71 ng/ml in horses at risk for acute kidney injury. The results of both methods corresponded significantly. Podocin may be a potential biomarker of clinical kidney disease in horses and may be used in the detection of glomerular injury. However, its use is limited by the possibility of physiological podocyturia. LC-MS-MRM seems to be a more sensitive method to evaluate the presence of podocin than the ELISA test, whilst selected tryptic peptides of podocin appear to apply to horses. The ELISA test showed greater effectiveness in excluding the disease than in confirming it.