Abstract
Purpose: This study aimed to examine the effects of
Empagliflozin on the mice model of HFD/STZ-induced T2DM and liver
fibrosis, and the correlations with gut microbiota.
Methods: The HFD/STZ-induced T2DM and liver fibrosis mice were
treated with Empagliflozin for 6 weeks. After the intervention, OGTT and
IPGTT were performed to assess glucose tolerance and insulin resistance
in mice. The histological chemistry and indicators of liver pathology
and liver fibrosis were assessed. Moreover, 16S rRNA amplicon sequencing
for gut microbiota was performed to explore the changes of gut bacterial
composition. And we analyzed the correlation between alterations in
intestinal microbial composition and liver fibrosis score or glucose
metabolic indicators.
Results: 6-week Empagliflozin intervention improved glucose
metabolism, and attenuated liver fibrosis in HFD/STZ-induced mice, which
might be related to the alterations of gut microbiota. Furthermore, the
abundance of Lactobacillus was increased, whileRuminococcus and Adlercreutzia were reduced in
Empagliflozin-treated mice, which were positively associated with liver
fibrosis and glucose metabolism in correlation analysis.
Conclusion: Empagliflozin ameliorated glucose metabolic
dysfunction and liver fibrosis in HFD/STZ-induced mice, whose effects
might be due to the beneficial balance of gut microbiota composition.
Our study provided evidence and highlighted improvement of gut-liver
axis by inhibition of SGLT2 in T2DM and liver fibrosis.
Key Words: SGLT2 inhibitors, Liver fibrosis, T2DM, Gut
microbiota, Gut-liver axis
INTRODUCTION
Liver fibrosis is the end-stage outcome of chronic liver injury induced
by various factors such as non-alcoholic fatty liver disease (NAFLD),
alcohol abuse, and chronic viral infections1. NAFLD
has been identified as a major inducer of liver fibrosis, and diabetes
mellitus (DM) has been reported to accelerate the progression of NAFLD
to liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC)2,3. Insulin resistance and intestinal flora are
potential mechanisms contributing to the development of liver fibrosis
in the context of the complex interaction between DM and
NAFLD4. However, the available interventions for liver
fibrosis are currently limited5. Further research is
needed to explore potential pharmacotherapy targeting the underlying
common pathological mechanisms of NAFLD and DM to alleviate liver
fibrosis.
Sodium-glucose cotransporter 2 (SGLT2) inhibitors (including
Dapagliflozin, Canagliflozin and Empagliflozin) are novel hypoglycemic
agents that lower blood glucose mainly by inhibiting glucose
reabsorption from the proximal tubules of the kidney and increasing
urinary glucose excretion6. In recent years, several
studies have shown that SGLT2 inhibitors may improve liver fibrosis in
addition to significant hypoglycemic effects7,8. A
multicenter, randomized controlled trial (RCT) revealed that long-term
ipragliflozin treatment ameliorates liver fibrosis in patients with
NAFLD and T2DM9. Another study based on real-world
data also showed that SGLT2 inhibitors not only lowered blood glucose
but also improved liver fatty infiltration and fibrosis in patients with
NAFLD and T2DM, suggesting that SGLT2 inhibitors may be potential drugs
for anti-liver fibrosis10. Interestingly, another
study also discovered that Empagliflozin improves liver fibrosis in
patients with NAFLD without T2DM, indicating that SGLT2 inhibitors may
ameliorate liver fibrosis through non-hypoglycemic
effects11. However, the anti-fibrotic effect of SGLT2
inhibitors still needs to be further confirmed, and it remains unclear
whether SGLT2 inhibitors can alleviate liver fibrosis through other
mechanisms rather than glycemic control or weight reduction. Since it
remains uncertain whether SGLT2 is expressed in the liver, the
anti-fibrotic effect of SGLT2 inhibitors may be indirectly through the
improvement of insulin resistance or gut microbiota4.
In recent years, a number of studies have found that SGLT2 inhibitors
seem to be able to regulate intestinal flora and play a protective role
in many diseases12,13. Hao et al. found that
Empagliflozin can mitigate atherosclerosis partly by regulating
intestinal microbiota14. Similarly, Deng et al. also
reported that Empagliflozin can ameliorate type 2 diabetes
mellitus-related diabetic nephropathy via altering the gut
microbiota15. These evidences indicate that SGLT2
inhibitors can regulate gut microbiota and play a significant role in
improving diseases. Notably, dysbiosis of the gut microbiota has been
observed in patients with T2DM and NAFLD, highlighting its association
with these conditions16,17. Therefore, it is plausible
that SGLT2 inhibitors attenuate liver fibrosis by modulating the gut
microbiota. However, the interactions among SGLT2 inhibitors, gut
microbiota, and liver fibrosis remain unclear and necessitate further
investigation. Consequently, the aim of the present study is to provide
additional evidence regarding the therapeutic effects of SGLT2
inhibitors on liver fibrosis using a high-fat diet/streptozotocin
(HFD/STZ)-induced T2DM and liver fibrosis mouse model and explore the
potential relationship between the observed anti-fibrotic effects and
modulation of the gut microbiota.
RESULTS
2.1 Empagliflozin had no significant effect on body weight and
food intake inHFD/STZ-induced T2DM
mice
To observe the effects of SGLT2 inhibitors on liver fibrosis,
HFD/STZ-induced liver fibrosis with type 2 diabetes mellitus models were
treated with Empagliflozin (Figure 1A). Compared to the Chow diet group,
the body weight of mice in HFD group increased significantly (P
< 0.05), while mice showed a significant decrease in body
weight (P < 0.05) and a significant increase in blood glucose
(P < 0.05) after intraperitoneal injection of STZ at week 8
(Supplementary Figure 1 and 2). After 6 weeks of Empagliflozin
administration, no significant changes were observed both in body weight
(Figure 1B) and food intake (Supplementary Figure 3).