Insulin Resistance and Obesity Affect Lipid Profile in the Salivary Glands

Abstract

In today's world wrong nutritional habits together with a low level of physical activity have given rise to the development of obesity and its comorbidity, insulin resistance. More specifically, many researches indicate that lipids are vitally involved in the onset of a peripheral tissue (e.g., skeletal muscle, heart, and liver) insulin resistance. Moreover, it seems that diabetes can also induce changes in respect of lipid composition of both the salivary glands and saliva. However, judging by the number of research articles, the salivary glands lipid profile still has not been sufficiently explored. In the current study we aim to assess the changes in the main lipid fractions, namely, triacylglycerols, phospholipids, free fatty acids, and diacylglycerols, in the parotid and the submandibular salivary glands of rats exposed to a 5-week high fat diet regimen. We observed that the high caloric fat diet caused a significant change in the salivary glands lipid composition, especially with respect to PH and TG, but not DAG or FFAs, classes. The observed reduction in PH concentration is an interesting phenomenon frequently signifying the atrophy and malfunctions in the saliva secreting organs. On the other hand, the increased accumulation of TG in the glands may be an important clinical manifestation of metabolic syndrome and type 2 diabetes mellitus.

Figure 1

Effects of high fat diet feeding on the salivary glands lipid profile ((a) parotid salivary glands; (b) submandibular salivary glands). Ctrl: control group (n = 8); DG: diacylglycerols; FFAs: free fatty acids; HFD: high fat diet fed group (n = 8); PH: phospholipids; PSG: parotid salivary glands; SMSG: submandibular salivary glands; TG: triacylglycerols; ∗: difference versus Ctrl (p < 0.05).