Characterizing the impact of SGLT2 inhibition on hepatic inflammation and cellular response in a type 2 diabetic mouse model

Abstract

Type 2 diabetes (T2D) is associated with several comorbidities including nonalcoholic fatty liver disease (NAFLD). NAFLD is characterized by the presence of steatosis with or without hepatic fibrosis and is associated with insulin resistance, inflammation, and hyperlipidemia. Recently, sodium-glucose co-transport 2 inhibitors (SGLT2i) such as Empagliflozin (Empa), have emerged as a treatment option for patients with T2D by blocking renal glucose reabsorption and improving glycemic control. Whether these inhibitors may attenuate T2D-associated NAFLD is still under investigation. To explore this possibility, we challenged TallyHo (TH) mice with a 60% high-milk fat diet (HMFD) with or without Empa (10mg/kg BW) for 12 weeks. Like humans, TH mice possess several quantitative trace loci associated with diabetic/obese phenotypes. In this study, we found that Empa treatment decreased hepatic steatosis in both male and female TH mice. However, the 12-week dietary challenge was not sufficient to induce fibrosis and inflammation (Kurtz et al. 2022). Thus, we have extended the trial to 24-weeks with the hypothesis that Empa promotes anti-inflammatory responses through macrophage infiltration and cellular signaling. Protein expression of the cGAS-STING pathway (STING, pTBK1, TBK1, pIRF3, IRF3), inflammasome pathway (AIM2, ASC/TMS1) and apoptosis signaling pathway (Caspase-3) showed no significant changes between diet or treatment. Additionally, activity of p50 and p65 of NF-κB (measured through nuclear expression) was not changed between treatment groups.While Empa does not appear to alter cellular-mediated inflammatory pathways, we did note changes in cytokine expression. Using a large-scale screen to probe for more than 60 inflammatory markers, we observed elevated levels of three pro-inflammatory cytokines (IL-3, CCL2, M-CSF; p<0.05) in livers from Empa-treated mice while there was downregulation of p40/p70 (p<0.01). The screen of plasma samples identified elevated levels of MIP-1γ (p<0.01) and identified decreased levels of three cytokines (IL-9, TIMP1, TPO; p<0.05) in Empa-treated mice. To further understand the role of macrophage infiltration as a response to increased inflammation, immunofluorescence on liver section with F4/80, a macrophage marker, was performed. There were no significant differences in the density or localization of Kupffer cells between treatments and diets for both sexes. Thus, it is hypothesized that Empa promotes the polarization of macrophages from M1 (pro-inflammatory) to M2 (anti-inflammatory) to promote tissue regeneration and repair. Staining of M1 and M2 macrophage markers are currently underway. Additionally, it has been determined that the upregulation of TIMP1 leads to matrix deposition. Efforts are currently underway to quantify portal inflammation using QuPath. Collectively, the data shows that Empa treatment for 24-weeks does not alter cellular signaling, and potentially alters macrophage signaling to combat NAFLD. NIDDK This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.