Kabara Ed, Sordillo Lorraine M, Holcombe Sue, Contreras G Andres
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
Comp Immunol Microbiol Infect Dis. 2014 Jan;37(1):49-58. doi: 10.1016/j.cimid.2013.10.007. Epub 2013 Nov 7.
The periparturient period of dairy cows is characterized by intense lipid mobilization from adipose tissue leading to increased plasma concentrations of nonesterified fatty acids (NEFA). High NEFA are a predisposing factor for inflammatory based diseases. A major component of these diseases is uncontrolled macrophage/monocyte inflammatory responses. Changes in the endocrine activity of adipose tissue during the periparturient period could impact macrophage function by modifying the secretion of adipokines including adiponectin. Currently, the effects of adiponectin on monocyte activation in dairy cattle are unknown. In humans and rodents, this adipokine regulates monocyte phenotype and alterations in its plasma levels are linked with the development of inflammatory diseases. The objectives of this study were to establish associations between plasma adiponectin expression dynamics and different markers of lipid mobilization during the periparturient period of dairy cows and to characterize the effects of adiponectin on the inflammatory response of bovine monocytes. Plasma adiponectin, NEFA, BHB, albumin, and subcutaneous and retroperitoneal fat depots depth were measured during the periparturient period of dairy cows. In vitro, bovine monocytes were cultured with adiponectin to assess changes in pro-inflammatory responses following LPS stimulation. Results from this study demonstrate that alterations in plasma adiponectin levels in periparturient cattle are inversely correlated with the concentrations of plasma NEFA, an important marker of lipid mobilization. Furthermore, adiponectin exposure significantly decreased monocyte expression of TNFα after LPS stimulation thus markedly reducing their inflammatory response. Reduced plasma adiponectin during the periparturient period could predispose dairy cows to the development of uncontrolled monocyte inflammatory responses.
奶牛围产期的特点是脂肪组织中脂质大量动员，导致血浆中非酯化脂肪酸（NEFA）浓度升高。高浓度的NEFA是炎症性疾病的诱发因素。这些疾病的一个主要成分是不受控制的巨噬细胞/单核细胞炎症反应。围产期脂肪组织内分泌活性的变化可能通过改变包括脂联素在内的脂肪因子的分泌来影响巨噬细胞功能。目前，脂联素对奶牛单核细胞活化的影响尚不清楚。在人类和啮齿动物中，这种脂肪因子调节单核细胞表型，其血浆水平的改变与炎症性疾病的发展有关。本研究的目的是建立奶牛围产期血浆脂联素表达动态与不同脂质动员标志物之间的关联，并表征脂联素对牛单核细胞炎症反应的影响。在奶牛围产期测量血浆脂联素、NEFA、β-羟基丁酸（BHB）、白蛋白以及皮下和腹膜后脂肪库深度。在体外，将牛单核细胞与脂联素一起培养，以评估脂多糖（LPS）刺激后促炎反应的变化。本研究结果表明，围产期奶牛血浆脂联素水平的变化与血浆NEFA浓度呈负相关，NEFA是脂质动员的一个重要标志物。此外，脂联素处理显著降低了LPS刺激后单核细胞中肿瘤坏死因子α（TNFα）的表达，从而显著降低了它们的炎症反应。围产期血浆脂联素水平降低可能使奶牛易发生不受控制的单核细胞炎症反应。
