Combination therapy with losartan and L-carnitine protects against endothelial dysfunction of streptozotocin-induced diabetic rats.

Endothelial dysfunction is a critical factor during the initiation of diabetic cardiovascular complications and angiotensin II appears to play a pivotal role in this setting. The present study aimed to investigate whether the combination therapy with losartan and the nutritional supplement, L-carnitine can provide an additional protection against diabetes-associated endothelial dysfunction and elucidate the possible mechanism(s) underlying this effect. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) (60 mg/kg) in rat. Effects of losartan (20 mg/kg, orally, 3 months) and L-carnitine (200 mg/kg, orally, 3 months) on tumor necrosis factor (TNF)-α, oxidative stress parameters, endothelial nitric oxide synthase expression (eNOS), and vascular function were evaluated. Our results showed a marked increase in aortic superoxide anion (O2(-)) production and serum malondialdehyde (MDA) level alongside attenuating antioxidant enzyme capacities in diabetic rats. This was associated with a significant increase in anigiotensin II type 1 receptor gene expression and TNF-α serum level of diabetic rats alongside reducing aortic eNOS gene expression and nitric oxide (NO) bioavailability. The single or combined administration of losartan and L-carnitine significantly inhibited these changes. Additionally, the vascular endothelium-dependent relaxation with acetylcholine (ACh) in aortic diabetic rat was significantly ameliorated by the single and combined administration of losartan or L-carnitine. Noteworthy, the combination therapy exhibited a more profound response over the monotherapy. Collectively, our results demonstrate that the combined therapy of losartan and L-carnitine affords additive beneficial effects against diabetes-associated endothelial dysfunction, possibly via normalizing the dysregulated eNOS and reducing the inflammation and oxidative stress in diabetic rats.

Sleem M ，Taye A ，El-Moselhy MA ，Mangoura SA ... -  《-》

Combination therapy with spironolactone and candesartan protects against streptozotocin-induced diabetic nephropathy in rats.

Diabetic nephropathy is one of the most common causes of end-stage kidney disease. Aldosterone and angiotensin II appear to play a crucial role in the pathogenesis of this disease. The present study aimed to investigate effects of the combination therapy with spironolactone and candesartan on diabetic nephropathy and elucidate the underlying mechanism(s) involved. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (STZ) (55 mg/kg). The diabetic rats were orally treated with spironolactone (50 mg/kg/day) and/or candesartan (1 mg/kg/day) for 8 weeks. Administration of STZ caused a marked elevation in the serum level of creatinine, urea and urinary albumin-creatinine ratio (ACR). This was associated with upregulated renal protein levels of nuclear factor-kappa B (NF-κB), transforming growth factor (TGF)-β, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) alongside increasing the renal superoxide anion (O2(-)) production, malondialdehyde (MDA) level and the systolic blood pressure. There was a marked decrease in nitric oxide (NO) bioavailability and antioxidant enzyme capacity. The combined therapy of spironolactone and candesartan significantly normalized the oxidative stress and fibrotic/inflammatory alterations. Additionally, the elevated blood pressure was attenuated by administration of candesartan alone or in combination. This was associated with improving the renal function parameters. The combined therapy exhibited more profound response compared to the monotherapy. In conclusion, our results demonstrate that the combined therapy of spironolactone and candesartan can confer an additive benefit over the use of either drug alone against STZ-induced diabetic nephropathy, presumably via attenuating the inflammatory responses and oxidative status markers.

Hofni A ，El-Moselhy MA ，Taye A ，Khalifa MM ... -  《-》

Catechin averts experimental diabetes mellitus-induced vascular endothelial structural and functional abnormalities.

Bhardwaj P ，Khanna D ，Balakumar P 《-》

Lycopene attenuates endothelial dysfunction in streptozotocin-induced diabetic rats by reducing oxidative stress.

Zhu J ，Wang CG ，Xu YG 《-》

Spironolactone improves endothelial dysfunction in streptozotocin-induced diabetic rats.

Adel H ，Taye A ，Khalifa MM 《-》