Gene expression of adipokines in placentas of cows from Northeastern Brazil with and without hyperketonemia and their interactions with metabolic biomarkers.

The objective was to analyze the mRNA expression of leptin, leptin receptor (ObRb), adiponectin, adiponectin receptor (AdipoR1), and resistin in the placental tissue of cows with and without hyperketonemia, relating it to their metabolic profile. Samples were collected from 135 cows during birth, divided into two groups: G1: without hyperketonemia (n = 120) and G2: with hyperketonemia (n = 15). Biochemical and hormonal indicators and insulin sensitivity were evaluated. Placental fragments were analyzed by qPCR. The variables were tested for normality and Pearson's correlation coefficient was applied. The significance level was 5%. Cows with hyperketonemia showed increased concentrations of NEFA (p = 0.0002), urea (p = 0.0302), higher expressions of leptin (p = 0.0174) and ObRb (p < 0.0001), while healthy cows showed higher expression of AdipoR1 (p < 0.0001) and resistin (p = 0.0435). Glucose concentrations were lower in G2 (p = 0.0132), as were the percentages of RQUICKIβHB (p < 0.0001). Among the varying degrees of correlations between the variables, the following stand out: positive correlation of leptin expression with β-Hydroxybutyrate and ObRb expression; positive correlation of ObRb expression with β-hydroxybutyrate, NEFA, GGT and AST, and negative correlation with glucose; positive correlation of AdipoR1 expression with glucose, RQUICK and RQUICKβHB, and negative correlation with β-Hydroxybutyrate, NEFA and GGT. Gene expression analysis of adipokines in the placenta is a promising tool to understand their role in metabolic regulation in cows, especially in the dynamics of hyperketonemia. It is concluded that the placental production of these hormones has an important contribution to metabolic conditions in the transition period, bringing implications for the physiology, health and productivity of females.