Background Approaches to the evaluation of pulmonary arterial hypertension (PAH) in premature calves by using lung-specific epithelial and endothelial biomarkers are needed. Objective To investigate the evaluation of PAH in premature calves with and without respiratory distress syndrome (RDS) by using lung-specific epithelial and endothelial biomarkers and determine the prognostic value of these markers in premature calves. Animals Fifty premature calves with RDS, 20 non-RDS premature calves, and 10 healthy term calves. Methods Hypoxia, hypercapnia, and tachypnea were considered criteria for RDS. Arterial blood gases (PaO₂, PaCO₂, oxygen saturation [SO₂], base excess [BE], and serum lactate concentration) were measured to assess hypoxia. Serum concentrations of lung-specific growth differentiation factor-15 (GDF-15), asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and surfactant protein D (SP-D) were measured to assess PAH. Results Arterial blood pH, PaO₂, SO₂, and BE of premature calves with RDS were significantly lower and PaCO₂ and lactate concentrations higher compared to non-RDS premature and healthy calves. The ADMA and SP-D concentrations of premature calves with RDS were lower and serum ET-1 concentrations higher than those of non-RDS premature and healthy calves. No statistical differences for GDF-15 and VEGF were found among groups. Conclusions and Clinical Importance Significant increases in serum ET-1 concentrations and decreases in ADMA and SP-D concentrations highlight the utility of these markers in the diagnosis of PAH in premature calves with RDS. Also, we found that ET-1 was a reliable diagnostic and prognostic biomarker for PAH and predicting mortality in premature calves.

This study aimed to assess the usefulness of injury biomarkers specific to the intestines in identifying the presence and degree of intestinal epithelial damage in coccidiosis-infected calves. Forty calves of various breeds and sexes, aged 21 days to 60 days, were used in the study. Of these, 30 were in the experimental group, and 10 were healthy control. The McMaster Oocyte counting technique was used to diagnose Eimeria and confirm clinical coccidiosis. Cases with clinical signs and more than 5,000 oocysts in gram feces were included in the study. All calves had blood samples drawn at the 0th hours and 72nd hours. Blood gas measurements were performed with a blood gas analyzer. Hemogram was performed with an automated hematologic analyzer. Bovine-specific enzyme-linked immunosorbent analysis (ELISA) test kits were used to measure the intestinal fatty acid binding protein (I-FABP), trefoil factor-3 (TFF-3), intestinal alkaline phosphatase (IAP), claudin-3 (CLD-3), intestinal smooth muscle actin (ACTG2), and interleukin-8 (IL-8) biomarkers from serum samples. Calves with coccidiosis received a single dose of toltrazuril (15 mg/kg) and supportive care. Before treatment (0th hours) in coccidiosis-infected calves, serum I-FABP and CLD-3 levels were greater than in healthy calves (p<0.05), and after treatment (72nd hours), serum TFF-3 and ACTG2 levels were higher than in healthy calves. There was a significant decrease in serum IL-8 levels in coccidiosis-infected calves after treatment (72nd hours) compared to pre-treatment (0th hours) (p<0.05). I-FABP, TFF-3, CLD-3, ACTG2, and IL-8 are helpful and reliable biomarkers that can be utilized to assess the presence of intestinal epithelium injury in coccidiosis-infected calves.

Mitochondrial biogenesis (MB) induction has recently emerged as potential therapeutic approaches in kidney pathology and the mitochondria-targeted therapies should be investigated to improve treatment of animals with kidney diseases. This study aimed to investigate the effects of MB induction with sildenafil citrate on the cGMP/NO pathway, glomerular filtration, and reduction of kidney damage and fibrosis (TGF-β/SMAD pathway) in cats with acute on chronic kidney disease (ACKD). Thirty-three cats were divided into the non-azotemic (healthy) group (n:8) and the ACKD group (n:25), comprising different breeds, sexes, and ages. Sildenafil citrate was administered to the non-azotemic and ACKD groups (2.5 mg/kg, PO, q12 hours) for 30 days. Serum and urine NO, MDA, NGAL, KIM-1, TGF-β1, IL-18, FGF 23, PGC-1α and cGMP concentrations were measured. Serum cGMP concentrations increased (P < 0.05) in the non-azotemic group during the 2nd (median 475.99 pmol/mL) and 3rd (median 405.01 pmol/mL) weeks of the study, whereas serum cGMP concentrations decreased in the ACKD group during the 4th(median 188.52 pmol/mL) week compared to the non-azotemic group (P < 0.05). No difference was observed in serum biomarker concentrations except NO, which increased in the 4th week (P < 0.05). The urinary concentrations of NO, MDA, PGC-1α, TGF-β1, NGAL, KIM-1, IL-18, and FGF 23 in the ACKD group were found to be higher compared to those in the non-azotemic group from the 1st to the 4th week (P < 0.05). In the ACKD group, the urine PGC-1α concentration in the 2nd (median 6.10 ng/mL) week was lower compared to that in the 0 and 1st (median 7.65 and 7.21 ng/mL, respectively) week, and the NO concentration in the 3rd (median 28.94 µmol/mL) week was lower than that in the 0th (median 37.43 µmol/mL) week (P < 0.05). While sildenafil citrate has been determined to induce a low level of MB and to have a beneficial effect on glomerular filtration, it is observed to be ineffective in mitigating renal damage and fibrosis via the TGF-β/SMAD pathway in cats with ACKD.

The purpose of the present study was to establish the development of acute kidney injury (AKI) and evaluate the usefulness of kidney-specific biomarkers in diagnosing AKI in premature calves with respiratory distress syndrome (RDS). Ten-term healthy and 70 premature calves with RDS were enrolled. Clinical examination, blood gases, and chemical analysis were performed at admission and 72 h. Serum concentrations of blood urea nitrogen (BUN), creatinine (Cre), phosphorus (P), cystatin-C (Cys-C), neutrophil gelatinase-associated lipocalin (NGAL), uromodulin (UMOD), and liver-type fatty acid-binding protein (L-FABP) were measured to evaluate kidney injury. Our findings showed that 38.5% of the premature calves with RDS developed AKI. The RDS-AKI group had a 4-fold higher mortality risk than the RDS-non-AKI group. Cys-C, with 90% and 89% specificity, and NGAL, with 100% sensitivity and 85% specificity, were the most reliable biomarkers to determine AKI in premature calves. The usefulness of any biomarker to predict mortality was not found to be convincing. In conclusion, AKI can develop as a consequence of hypoxia in premature calves and may increase the risk of mortality. In addition, serum Cys-C and NGAL concentrations may be useful in the diagnosis of AKI in premature calves with RDS.

Background: Displaced abomasum (DA) is one of the most important metabolic disorders of dairy cattle. In DA, ischaemic damage may occur as a result of impaired perfusion due to abomasal displacement, which may result in gastrointestinal mucosal damage.Objective: Investigation of gastrointestinal tissue damage in cattle with right displacement of the abomasum (RDA) and left displacement of the abomasum (LDA) using intestinal‐related biomarkers.Methods: Forty‐eight DA (24 LDA, 24 RDA) and 15 healthy Holstein dairy cows were enrolled between March 2021 and July 2022. Serum biomarkers including gamma‐enteric smooth muscle actin (ACTG‐2), liver‐fatty acid binding proteins (L‐FABP), platelet activating factor (PAF), trefoil factor‐3 (TFF‐3), leptin, claudin‐3 and interleukin‐8 (IL‐8) concentrations were measured from venous blood samples.Results: L‐FABP concentrations in the LDA group and TFF‐3 concentrations in the RDA group were lower than in the control group. The leptin concentration of the RDA group was higher than that of the other groups. There was a negative correlation between lactate, leptin and IL‐8 concentrations. There was a negative correlation between lactate and TFF‐3, whereas leptin and lactate were positively correlated. Leptin was the more reliable biomarker for discriminating between RDA and LDA cases.Conclusion: Changes in serum L‐FABP, TFF‐3 and leptin concentrations in cattle with DA may reflect acute intestinal injury and the subsequent repair phase. However, these biomarkers had poor diagnostic performance in discriminating between healthy and cattle with DA, while leptin emerged as the most useful marker in differentiating LDA from RDA cases.

The aim of this study was to investigate the role of endothelial activation and glycocalyx degradation in the pathogenesis of feline panleukopenia (FPL) using biomarkers and to determine the diagnostic and prognostic significance of these biomarkers. Thirty cats with FPL and 10 healthy cats were enrolled. Clinical examination, blood gases, and complete blood count (CBC) were performed at enrollment. Endothelin-1 (ET-1), asymmetric dimethylarginine (ADMA), vascular endothelial growth factor-A (VEGF-A), and syndecan-1 (Syn-1) concentrations were measured using feline specific commercial enzyme-linked immunosorbent assay (ELISA) kits to assess endothelial glycocalyx damage. Nineteen (63.3%) of the cats with FPL recovered and survived, while 11 (36.7%) died. In cats with panleukopenia, acidemia was the most important blood gas finding, while leukopenia, lymphopenia, monocytopenia, granulocytopenia, and thrombocytopenia were the most dominant CBC findings. ET-1, ADMA, VEGF-A, and Syn-1 concentrations were significantly higher in cats with panleukopenia (p < 0.01). Serum Syn-1 and ET-1 concentrations were found to be useful in predicting mortality. In conclusion, the fact that the concentrations of all endothelial glycocalyx biomarkers (ET-1, ADMA, VEGF-A, Syn-1) were higher in cats with panleukopenia compared to healthy cats suggests that endothelial glycocalyx damage occurs during panleukopenia infection. In addition, Syn-1 and ET-1 were found to be potential prognostic factors with high sensitivity and specificity.