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Prevention of diabetic nephropathy in rats by prostaglandin E receptor EP1-selective antagonist
Hisashi Makino1, Issei Tanaka, Masashi Mukoyama
1Department of Medicine and Clinical Science, Department of Pharmacology, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 806-8507, Japan.
Abstract:
Local production of prostaglandins (PGs) in the kidney is increased in clinical and experimental diabetic nephropathy, but the role of PGs in the pathogenesis and progression of diabetic nephropathy has remained unclear. It is here shown that an orally active antagonist selective for the PGE receptor EP1 subtype potently prevents the progression of nephropathy in streptozotocin-induced diabetic rats. The effects are shown by ameliorated renal and glomerular hypertrophy, decreased mesangial expansion, inhibited transcriptional activation of transforming growth factor-beta (TGF-beta) and fibronectin, and complete suppression of proteinuria. In vitro, this agent completely inhibits TGF-beta and fibronectin upregulation in mesangial cells cultured under high-glucose conditions. These data indicate that the PGE2-EP1 system plays a crucial role in the development of diabetic renal injury in rats. It is further shown that both the EP1 antagonist and aspirin, a nonselective PG synthase inhibitor, markedly attenuate mesangial expansion, whereas only the EP1 antagonist inhibits glomerular hypertrophy and proteinuria, which suggests that these changes are caused by different mechanisms. This study reveals a potential usefulness of selective EP1 blockade as a novel therapeutic strategy for diabetic nephropathy and also brings a new insight into our understanding of this disease.
Insights
Blocking the PGE2-EP1 pathway in the kidneys significantly prevents diabetic nephropathy progression in rats. This targeted approach reduces kidney damage and protein loss, offering a potential new treatment for diabetic kidney disease.
Area of Science:
- Nephrology
- Endocrinology
- Pharmacology
Background:
- Prostaglandins (PGs) are implicated in diabetic nephropathy, but their specific role remains unclear.
- Increased local kidney prostaglandin production is observed in diabetic nephropathy.
Purpose of the Study:
- To investigate the role of the PGE2-EP1 receptor system in diabetic nephropathy pathogenesis.
- To evaluate the therapeutic potential of a selective EP1 receptor antagonist in a rat model of diabetic nephropathy.
Main Methods:
- Utilized streptozotocin-induced diabetic rats to model diabetic nephropathy.
- Administered an orally active, selective EP1 receptor antagonist.
- Assessed renal and glomerular hypertrophy, mesangial expansion, TGF-beta and fibronectin expression, and proteinuria.
- Conducted in vitro studies using mesangial cells under high-glucose conditions.
Main Results:
- The EP1 antagonist potently prevented diabetic nephropathy progression in rats.
- Treatment ameliorated renal and glomerular hypertrophy, decreased mesangial expansion, and inhibited TGF-beta and fibronectin upregulation.
- Complete suppression of proteinuria was observed with EP1 antagonist treatment.
- In vitro, the antagonist inhibited TGF-beta and fibronectin upregulation in high-glucose cultured mesangial cells.
- EP1 antagonist demonstrated distinct effects on glomerular hypertrophy and proteinuria compared to aspirin.
Conclusions:
- The PGE2-EP1 system plays a critical role in the development of diabetic renal injury in rats.
- Selective EP1 receptor blockade represents a promising novel therapeutic strategy for diabetic nephropathy.
- Different mechanisms contribute to the various pathological changes observed in diabetic nephropathy.