Milk-soluble formula increases food intake and reduces Il6 expression in elderly rat hypothalami

Abstract

Malnutrition in the elderly is accompanied by several metabolic dysfunctions, especially alterations in energy homeostasis regulation and a loss of insulin responsiveness. Nutritional recommendations aim to enrich food with high protein and energy supplements, and protein composition and lipid quality have been widely studied. Despite the numerous studies that have examined attempts to overcome malnutrition in the elderly through such nutritional supplementation, it is still necessary to study the effects of a combination of protein, lipids, and vitamin D (VitD). This can be done in animal models of elderly malnutrition. In the present study, we investigated the effects of several diet formulae on insulin responsiveness, inflammation, and the hypothalamic expression of key genes that are involved in energy homeostasis control. To mimic elderly malnutrition in humans, elderly Wistar rats were food restricted (R, K50%) for 12 weeks and then refed for 4 weeks with one of four different isocaloric diets: a control diet; a diet where milk soluble protein (MSP) replaced casein; a blend of milk fat, rapeseed, and DHA (MRD); or a full formula (FF) diet that combined MSP and a blend of MRD (FF). All of the refeeding diets contained VitD. We concluded that: i) food restriction led to the upregulation of insulin receptor in liver and adipose tissue accompanied by increased Tnfa in the hypothalamus; ii) in all of the refed groups, refeeding led to similar body weight gain during the refeeding period; and iii) refeeding with MSP and MRD diets induced higher food intake on the fourth week of refeeding, and this increase was associated with reduced hypothalamic interleukin 6 expression.

Differential expression of hypothalamic, metabolic and inflammatory genes in response to short-term calorie restriction in juvenile obese- and lean-prone JCR rats

“… 40 We also found that hypothalamic pro-inflammatory cytokines and oxidative stress markers were significantly reduced in the obese-prone juvenile rats after 10 days of CR, whereas a similar degree of CR significantly increased these parameters in the lean-prone juvenile rats for the same period. The high level of hypothalamic pro-inflammatory cytokines observed in lean-prone rats following the CR relative to the free-feeding animals is in agreement with recent report showing that food restriction significantly increases hypothalamic expression of tumor necrosis factor-α in Wistar rats, 41 suggesting that in metabolically normal conditions, CR induces inflammatory stress, which might contribute to the onset of hypothalamic inflammation. Indeed, owing to the lower percentage of fat mass in the lean-prone rats, 36% of CR induced with the experimental protocol may be functionally defined as a severe CR that most likely induced physiological stress, which may contribute to the onset of hypothalamic inflammation as previously reported.…”

Effect of Vitamin D Supplementation on Inflammatory Biomarkers in School-Aged Children with Attention Deficit Hyperactivity Disorder

“…This finding supports the hypothesis that older age predicts a significant reduction in IL-6, and a greater dosage of vitamin D may have the potential to improve inflammatory factors [ 50 ]. More so, in two animal studies evaluating the effect of vitamin D supplementation on IL-6 and TNF- α in rats, reduced levels of cytokines were also mentioned [ 51 , 52 ].…”