Multivariate analysis of placental gene expression of adipokines and biochemical markers in cows with and without hyperketonemia

The aim of this study was to perform multivariate analysis of correlation between gene expression of leptin, leptin receptor (ObRb), adiponectin, adiponectin receptor (Adipo R1), and resistin in placental tissue with biochemical variables of the energy, protein, enzymatic, hormonal, and mineral profile, through multivariate analysis, in cows with and without hyperketonemia. Samples from 135 cows were collected during calving and subsequently distributed into two groups: G1 = control (β-hydroxybutyrate <1.2 mmol/L / n = 120); and G2 = with hyperketonemia (β-hydroxybutyrate ≥1.2 mmol/L / n = 15). Biochemical and hormonal indicators (NEFA, β-hydroxybutyrate, glucose, total protein, albumin, urea, creatinine, GGT, AST, chlorides, phosphorus, ionizable calcium, potassium, sodium, insulin, and cortisol ions) were evaluated, as well as insulin sensitivity. Placental fragments were collected and processed for mRNA analysis by qPCR, with 38 samples analyzed (G1 =23; G2 =15). The data were analyzed using SAS PROC MIXED, with normality checks and transformations applied when necessary. F/SNK or Mann-Whitney tests were used according to the data distribution. In the multivariate analysis, data imputation, SMOTE, and autoscaling were performed, followed by analyses using PCA, HCA, and PLS. A significance level of 5% was adopted. Hyperketotic cows showed higher expression of leptin (p = 0,0174) and ObRb (p < 0,0001), while healthy cows showed higher expression of AdipoR1 and resistin (p < 0,0001). Multivariate analyses indicated ObrRb, AdipoR1, and β-hydroxybutyrate as key variables in differentiating the groups, being representative of the hyperketonemia condition in cows at calving, highlighting the potential of placental adipokines as tools for diagnosis and prognosis of this metabolic disorder in these females.