SGLT-2 inhibitors as novel treatments of multiple organ fibrosis

Fibrosis, a significant health issue linked to chronic inflammatory diseases, affects various organs and can lead to serious damage and loss of function. Despite the availability of some treatments, their limitations necessitate the development of new therapeutic options. Sodium-glucose cotransporter 2 inhibitors (SGLT2i), known for their glucose-lowering ability, have shown promise in offering protective effects against fibrosis in multiple organs through glucose-independent mechanisms. This review explores the anti-fibrotic potential of SGLT2i across different tissues, providing insights into their underlying mechanisms and highlighting recent research advancements. The evidence positions SGLT2i as a potential future treatments for fibrotic diseases.

Identification of diverse sesquiterpenoids with anti-fibrotic potential from Inula japonica Thunb

In the chemical investigation of Inula japonica, a total of 29 sesquiterpenoids (1-29) were obtained, including pseudoguaine-, xanthane-, eudesmane-, and 1,10-secoeudesmane-type compounds, as well as their dimers. Among them, six new dimeric sesquiterpenoids, bisinulains A-F (1-5, 7), characterized by a [4 + 2] biogenetic pathway between different sesquiterpenoid monomers were identified. Additionally, three new monomers named inulaterins A-C (13, 18 and 21) were discovered. The structures of these compounds were determined through analysis of spectroscopic data, X-ray crystallographic data, and ECD experiments. To assess their potential anti-inflammatory activities, the sesquiterpenoid dimers were tested for their ability to inhibit NO production in LPS-stimulated RAW 264.7 cells. Furthermore, the compounds that exhibited anti-inflammatory effects underwent evaluation for their anti-fibrotic potential using a TGF-β-induced epithelial-mesenchymal transition model in A549 cells. As a result, bisinulain B (2) was screened out to significantly inhibit the production of cytokines involved in pulmonary fibrosis such as NO, α-SMA, collagen I and fibronectin.

Direct Blood Pressure-Independent Anti-Fibrotic Effects by the Selective Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone in Progressive Models of Kidney Fibrosis

INTRODUCTION

The nonsteroidal mineralocorticoid receptor (MR) antagonist finerenone and sodium-glucose cotransporter-2 (SGLT2) inhibitors have demonstrated clinical benefits in chronic kidney disease patients with type 2 diabetes. Precise molecular mechanisms responsible for these benefits are incompletely understood. Here, we investigated potential direct anti-fibrotic effects and mechanisms of nonsteroidal MR antagonism by finerenone or SGLT2 inhibition by empagliflozin in 2 relevant mouse kidney fibrosis models: unilateral ureter obstruction and sub-chronic ischemia reperfusion injury.

METHODS

Kidney fibrosis was induced in mice via unilateral ureteral obstruction or ischemia. In a series of experiments, mice were treated orally with the MR antagonist finerenone (3 or 10 mg/kg), the SGLT2 inhibitor empagliflozin (10 or 30 mg/kg), or in a direct comparison of both drugs. Interstitial myofibroblast accumulation was quantified via alpha-smooth muscle actin and interstitial collagen deposition via Sirius Red/Fast Green staining in both models. Secondary analyses included the assessment of inflammatory cells, kidney mRNA expression of fibrotic markers as well as functional parameters (serum creatinine and albuminuria) in the ischemic model. Blood pressure was measured via telemetry in healthy conscious compound-treated animals.

RESULTS

Finerenone dose-dependently decreased pathological myofibroblast accumulation and collagen deposition with no effects on systemic blood pressure and inflammatory markers in the tested dose range. Reduced kidney fibrosis was paralleled by reduced kidney plasminogen activator inhibitor-1 (PAI-1) and naked cuticle 2 (NKD2) expression in finerenone-treated mice. In contrast, treatment with empagliflozin strongly increased urinary glucose excretion in both models and reduced ischemia-induced albuminuria but had no effects on kidney myofibroblasts or collagen deposition.

DISCUSSION/CONCLUSION

Finerenone has direct anti-fibrotic properties resulting in reduced myofibroblast and collagen deposition accompanied by a reduction in renal PAI-1 and NKD2 expression in mouse models of progressive kidney fibrosis at blood pressure-independent dosages.

Effects of Finerenone Combined with Empagliflozin in a Model of Hypertension-Induced End-Organ Damage

INTRODUCTION

The nonsteroidal mineralocorticoid receptor (MR) antagonist finerenone and sodium-glucose cotransporter-2 (SGLT2) inhibitors have demonstrated clinical benefits in CKD patients with type 2 diabetes. Clinical data analyzing the potential value of a combination therapy are currently limited. We therefore investigated cardiorenal protection of respective mono- and combination therapy in a preclinical model of hypertension-induced end-organ damage.

METHODS

Cardiovascular (CV) morbidity and mortality were studied in hypertensive, N(ω)-nitro-L-arginine methyl ester-treated, renin-transgenic (mRen2)27 rats. Rats (10- to 11-week-old females, n = 13-17/group) were treated once daily orally for up to 7 weeks with placebo, finerenone (1 and 3 mg/kg), empagliflozin (3 and 10 mg/kg), or a combination of the respective low doses. Key outcome parameters included mortality, proteinuria, plasma creatinine and uric acid, blood pressure, and cardiac and renal histology.

RESULTS

Placebo-treated rats demonstrated a 50% survival rate over the course of 7 weeks. Drug treatment resulted in variable degrees of survival benefit, most prominently in the low-dose combination group with a survival benefit of 93%. Monotherapies of finerenone or empagliflozin dose-dependently reduced proteinuria, while low-dose combination revealed an early, sustained, and over-additive reduction in proteinuria. Empagliflozin induced a strong and dose-dependent increase in urinary glucose excretion which was not influenced by finerenone coadministration in the combination arm. Low-dose combination but not respective low-dose monotherapies significantly reduced plasma creatinine and plasma uric acid after 6 weeks. Treatment with finerenone and the low-dose combination significantly decreased systolic blood pressure after 5 weeks. There was a dose-dependent protection from cardiac and kidney fibrosis and vasculopathy with both agents, while low-dose combination therapy was more efficient than the respective monotherapy dosages on most cardiorenal histology parameters.

DISCUSSION/CONCLUSIONS

Nonsteroidal MR antagonism by finerenone and SGLT2 inhibition by empagliflozin confer CV protection in preclinical hypertension-induced cardiorenal disease. Combination of these 2 independent modes of action at low dosages revealed efficacious reduction in important functional parameters such as proteinuria and blood pressure, plasma markers including creatinine and uric acid, cardiac and renal lesions as determined by histopathology, and mortality indicating a strong potential for combined clinical use in cardiorenal patient populations.

Synthesis and anti-fibrotic effects of santamarin derivatives as cytotoxic agents against hepatic stellate cell line LX2

Liver fibrosis is a final result of extensive deposition of extracellular matrix (ECM) and starts with the activation and proliferation of hepatic stellate cells (HSCs). Our previous study showed that eudesmane sesquiterpenoid santamarin had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with IC₅₀ values of 16.5 ± 0.7 μM. To explore the structure-activity relationships, twenty-six derivatives were synthesized by modifying the hydroxyl group, double-bond and unsaturated lactone. Cytotoxicity evaluation suggested that eight derivatives (6, 9, 13, 17, 20 and 25-27) increased activity against HSC-LX2. Especially, derivatives 17, 20 and 25 displayed obvious cytotoxicity with IC₅₀ values of 6.4 ± 0.4, 4.6 ± 0.1, and 3.5 ± 0.1 μM, which were 3 to 5-fold higher than santamarin. Preliminary mechanisms study revealed that the active compound 20 exhibited more than 8-fold and 6-fold enhancement of inhibitory effect on the deposition of human hyaluronic acid (HA) and human laminin (HL) with IC₅₀ values of 7.6 ± 0.6 and 3.3 ± 1.2 μM.

Chronic effects of losartan on the muscles and the serologic profiles of mdx mice

AIMS

Losartan, an angiotensin II type 1 receptor blocker, attenuates transforming growth factor-β (TGF-β) signaling, which inhibits myogenic regeneration. Although many researchers have demonstrated that losartan has anti-fibrotic and protective effects on cardiac and skeletal muscles, for long-term administration to treat dystrophic disorders, it is essential to demonstrate not only the therapeutic effects of losartan on muscles but also its effects on other organs and on blood biochemistry.

MAIN METHODS

Mdx mice, an animal model of Duchenne muscular dystrophy (DMD), were fed losartan dissolved in tap water. After 44weeks, the skeletal (gastrocnemius), cardiac, and diaphragm muscles of mdx mice were removed. Tissue and blood samples were collected from all experimental animals. Effects of losartan on muscle regeneration, fibrosis, and blood enzymatic profiles were evaluated.

KEY FINDINGS

In histopathological findings and serum biochemistry analyses, chronic losartan administration showed muscular protective effects and inhibited fibrosis in skeletal (gastrocnemius), cardiac, and diaphragmatic muscles. In addition, losartan had no effects on other solid organs. Interestingly, losartan had beneficial effects on serum HDL ratio.

SIGNIFICANCE

This study demonstrates the therapeutic effects of losartan on muscles and its effects on other organs and on blood biochemistry. In conclusion, our results provide useful information for consideration of chronic losartan administration be as a treatment of DMD.