The Correlation between Extracellular Heat Shock Protein 70 and Lipid Metabolism in a Ruminant Model

Abstract

Metabolic stress in early lactation cows is characterized by lipolysis, ketogenesis, insulin resistance and inflammation because of negative energy balance and increased use of lipids for energy needs. In this study the relationship between lipid metabolite, lipid-based insulin resistance, and hepatocyte functionality indexes and tumor necrosis factor alpha (TNF-α) with extracellular heat shock protein 70 (eHsp70) was investigated. The experiment included 50 cows and all parameters were measured in blood serum. In cows with a more pronounced negative energy balance, the following was determined: a higher concentration of eHsp70, TNF-α, non-esterified fatty acid (NEFA), beta-hydroxybutyrate (BHB), NEFA to insulin and NEFA to cholesterol ratio and lower concentration of cholesterol, very low-density lipoproteins (VLDL), low density lipoproteins (LDL) and liver functionality index (LFI). The eHsp70 correlated negatively with the values of cholesterol, VLDL, LDL, and triglycerides, while correlated positively with the level of NEFA and BHB. A higher concentration of eHsp70 suggests the development of fatty liver (due to a higher NEFA to cholesterol ratio and lower LFI) and insulin resistance (due to a lower revised quantitative insulin sensitivity check index RQUICKI-BHB and higher NEFA to insulin ratio). The eHsp70 correlated positively with TNF-α. Both TNF-α and eHsp70 correlated similarly to lipid metabolites. In cows with high eHsp70 and TNF-α values we found higher concentrations of NEFA, BHB, NEFA to insulin and NEFA to cholesterol ratio and a lower concentration of triglycerides and VLDL cholesterol compared to cows that had only high TNF-α values. Based on the positive correlation between eHsp70 and TNF-α, their similar relations, and the additional effect of eHsp70 (high TNF-α + eHsp70 values) on lipid metabolites we conclude that eHsp70 has pro-inflammatory effects implicating lipolysis, fatty liver, and fat tissue insulin resistance.

Influence of Heat Stress on Body Surface Temperature and Blood Metabolic, Endocrine, and Inflammatory Parameters and Their Correlation in Cows

“…In dairy cows, P concentration decreases with the increase in glucose and insulin concentrations [62]. In cows in early lactation, significantly higher values of eHsp70, TNFα, NEFA, AST, and GGT are determined, as well as lower values of INS, RQUICKI, Ca, TGC, and CHOL compared to cows in mid-lactation, which is consistent with previous results and the presence of metabolic stress in early lactation [63][64][65]. Cows calved under heat stress exhibit lower values of NEFA, BHB, CHOL, and TGC during early lactation compared to cows calved in the thermoneutral period, which is confirmed by previous studies [66].…”

The Influence of Energy Balance, Lipolysis and Ketogenesis on Metabolic Adaptation in Cows Milked Twice and Three Times Daily

“…Metabolic adaptation to increasing MF corresponds to NEB of cows and homeorhesis in early lactation, which is characterized by increased lipolysis and ketogenesis with dominance of catabolic processes and the development of several unfavorable metabolic adaptations [21][22][23]. NEFA and BHB show significant correlations with parameters of metabolic profile, indicating the functional status of carbohydrate, fat, protein, mineral, and liver metabolism, as well as with hormones and indicators of cellular stress response in cows [24][25][26].…”

Haematological and chosen biochemical parameter assessment of the antioxidant system in red deer (Cervus elaphus) blood in early and late pregnancy

“…Its normal liver secretion rate is slower in ruminants than in non-ruminants, and in late ruminant pregnancy, VLDL levels could be even more diminished because of the increased demands of mammary gland for fatty acids, effecting the triglyceride serum levels. Lower VLDL synthesis might also reduce LDL serum levels ( 24 ). Depletion overall of lipoproteins produced by the liver and consequently falls in triglyceride values could additionally be effects of the reduction in the mass of the red deer liver by approximately ¼ in winter as one of its seasonal adjustments, to reduce the energy needs of alimentary visceral organs ( 1 ).…”