ORIGINAL ARTICLE: Gene expression of tumour necrosis factor and insulin signalling-related factors in subcutaneous adipose tissue during the dry period and in early lactation in dairy cows

Abstract

Summary Gene expression of adipose factors, which may be part of the mechanisms that underlie insulin sensitivity, were studied in dairy cows around parturition. Subcutaneous fat biopsies and blood samples were taken from 27 dairy cows in week 8 antepartum (a.p.), on day 1 postpartum (p.p.) and in week 5 p.p. In the adipose tissue samples, mRNA was quantified by real‐time reverse transcription polymerase chain reaction for tumour necrosis factor alpha (TNFα), insulin‐independent glucose transporter (GLUT1), insulin‐responsive glucose transporter (GLUT4), insulin receptor, insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2), regulatory subunit of phosphatidylinositol‐3 kinase (p85) and catalytic subunit of phosphatidylinositol‐3 kinase. Blood plasma was assayed for concentrations of glucose, β‐hydroxybutyric acid, non‐esterified fatty acids (NEFA) and insulin. Plasma parameters followed a pattern typically observed in dairy cows. Gene expression changes were observed, but there were no changes in TNFα concentrations, which may indicate its local involvement in catabolic adaptation of adipose tissue. Changes in GLUT4 and GLUT1 mRNA abundance may reflect their involvement in reduced insulin sensitivity and in sparing glucose for milk synthesis in early lactation. Unchanged gene expression of IRS1, IRS2 and p85 over time may imply a lack of their involvement in terms of insulin sensitivity dynamics. Alternatively, it may indicate that post‐transcriptional modifications of these factors came into play and may have concealed an involvement.

Longitudinal Profiling of the Tissue-Specific Expression of Genes Related with Insulin Sensitivity in Dairy Cows during Lactation Focusing on Different Fat Depots

“…In primiparous cows (Trial 2) we observed an increase in TNF-α mRNA abundance in all s.c. AT, at least at one of the sampling dates after parturition, which is different from the studies of Sadri et al [81] and van Dorland et al [66] reporting no changes during early lactation in pluriparous cows. In retroperitoneal AT TNF-α mRNA was less abundant at 105 than on 1 DIM.…”

“…Besides confirming earlier reports focusing on the transition period [66], [81], we also provided data about TNF-α mRNA expression in later stages of lactation. In contrast to TNFα, IL-6 mRNA in liver decreased during the transition period.…”

Invited review: Inflammation during the transition to lactation: New adventures with an old flame

“…In addition to the uterus, tissue transcript profiling has revealed inflammatory states in liver and adipose tissue in the first week of lactation (Loor et al, 2005;Sadri et al, 2010;Saremi et al, 2012;Gessner et al, 2013). Furthermore, a study of 240 multiparous cows demonstrated that elevated plasma haptoglobin concentrations from 2 to 8 d postpartum were associated with enhanced innate immune responses (Nightingale et al, 2015).…”

Adipose tissue lipolysis and remodeling during the transition period of dairy cows

“…During active AT remodeling, the expression and secretion of IL1-β, IL-6, resistin, and TNF-α by human adipocytes and ATM is increased, leading to impaired AT insulin signaling [74, 88]. In transition dairy cows, AT expression of IL-6, resistin, TNF-α, and other bioactive peptides associated with IR is increased compared to other stages of lactation [120–122]. Recent studies provide evidence for AT-specific IR during early lactation in high-yielding dairy cows.…”