Altered autophagy and sympathetic innervation in salivary glands from high-fat diet mice

Abstract

2 Highlights: Adiponectin levels decreased in the High Fat Diet group after three months  Autophagy increased after three months of High Fat Diet  mTOR showed no activation regarding the time point studied  Tyrosine hydroxylase decreased after two and three month of High Fat Diet Abstract Objective: to investigate the effects of a high fat diet (HFD) on salivary glands in vivo, in a mouse model. In particular, whether it will induce the appearance of fat cells in salivary glands, alterations related to autophagy, mTOR pathway and sympathetic innervation.Design: 27 adult female ICR mice were separated in six groups. Three groups fed with (HFD) containing 55% fat, for one, two and three month and another three groups fed with normal diet (2.7% of fat), for the same time periods. The submandibular glands and liver were dissected and part homogenized for protein analyses and part fixed in formalin for histological analyses Results: After three months the HFD fed mice total body weight fold change increased compared to controls. The Oil Red O staining showed no fat cells deposit in salivary gland however a large increase was observed in liver after three months of HFD.Adiponectin levels were significantly decreased in the HFD group after three months. The group fed with HFD for three months showed increased conversion of the LC3 autophagy marker in salivary gland. mTOR showed no activation regarding the time point studied.Tyrosine hydroxylase significantly decreased after two and three month of HFD. Conclusion:HFD caused several changes after three months however the earliest change was noticed after two months regarding sympathetic innervation. This suggests neural alteration may drive other diet induced changes in salivary glands. These early changes may be the starting point for longer term alterations of salivary glands with alterations in diet.3

High-Fat Diet–Induced Functional and Pathologic Changes in Lacrimal Gland

“…Previous studies showed that HFD-induced lipid accumulation in the kidney could have an onset as early as at 2 months, 32 whereas 3 months on this diet failed to induce lipid deposition in the salivary gland. 33 In this study, lipid deposition was already apparent in the lacrimal gland after 1 month on the HFD. The rapidity of this change indicates that the lacrimal gland is more sensitive to hyperlipidemia.…”

Adiponectin Interacts In-Vitro With Cementoblasts Influencing Cell Migration, Proliferation and Cementogenesis Partly Through the MAPK Signaling Pathway

“…In-vivo, Adiponectin secretion is regulated by the degree of obesity (Carbone et al, 2012). Its secretion is inversely proportional to the amount of adipose tissue (Swarbrick and Havel, 2008;Benedix et al, 2011;de Carvalho et al, 2017). It has been shown that patients with type 2 diabetes and obesity have lower serum Adiponectin levels than normal weight individuals (Cao et al, 2015).…”

High-fat diet-induced intestinal dysbiosis is associated with the exacerbation of Sjogren’s syndrome

“…On the other hand, the saliva secretions were also regulated by parasympathetic and sympathetic innervations (Proctor and Carpenter, 2014). Tyrosine hydroxylase, a useful marker of sympathetic nerves, significantly decreased after 2 and 3 months of HFD in submandibular glands (de Carvalho et al, 2017), which may explain the decrease in gland secretions. Additionally, HFD could perturb B-cell production, activity, and maturation by changing the composition of the gut microbiome (Shaikh et al, 2015;Petta et al, 2018).…”

“…HFD alone could induce a series of pathologic changes in the lacrimal gland (He et al, 2020). However, HFD failed to induce lipid deposition in the salivary gland (de Carvalho et al, 2017). On the other hand, the saliva secretions were also regulated by parasympathetic and sympathetic innervations (Proctor and Carpenter, 2014).…”