Reactive oxygen species and endothelins in diabetic nephropathy

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Clinical Efficacy of Alprostadil Combined with α-lipoic Acid in the Treatment of Elderly Patients with Diabetic Nephropathy

Objective

To evaluate the effect and toxicity of alprostadil combined with thioctic acid injection in the treatment of patients with diabetic nephropathy (DN).

Methods

Sixty two patients with DN were included in this study and randomly divided into control group (n=32) and experiment group (n=30). Patients in the control group were given alprostadil 20ug+NS 100ml ivgtt, qd and patients in the experiment group were given alprostadil 20ug+NS 100ml ivgtt combined with thioctic acid injection of 0.45g+100ml ivgtt, qd for 14 days. After treatment, the renal function and serum level of CRP, IL-6 and TNF-α were compared between the two groups.

Results

After two weeks of treatment, the serum level of CysC and UAER significant decreased for both control and experiment group with statistical difference of p<0.05. After treatment, the serum level of CysC were 1.40 ±0.46 mg/L and 1.02±0.33 for control and experiment group respectively (p<0.05). The post-treatment UAER in experiment group was significantly lower than those of control group with statistical difference (81.02±0.33 vs112.45±20.32, p<0.05) ug/min. The serum level of CRP, IL-6 and TNF-α were significantly decreased after treatment for both control and experiment group (p<0.05). And the post-treatment serum CRP, IL-6 and TNF-α in experiment group were significantly lower than those of control group with statistical difference (p<0.05). No significant side effects were found for the two groupsin the course of treatment.

Conclusion

Alprostadil combined with α-lipoic acid may improve renal function in patients with diabetic nephropathy by decreasing the levels of serum inflammatory factors.

Ethanol extracts of Rehmannia complex (Di Huang) containing no Corni fructus improve early diabetic nephropathy by combining suppression on the ET-ROS axis with modulate hypoglycemic effect in rats

AIM

Liuwei Dihuang (Rehmannia complex, RC) decoction, a classic prescription of Traditional Chinese Medicine (TCM), has been used in treating diabetic nephropathy (DN). Among the 6 crude medicines which contains Corni fructus is recognized as the active fraction for its effectiveness. We aimed to investigate, first, if without Corni fructus a modified RC could be still effective, second, if the ethanol extracts could be better than that of water extract and third, the beneficial effect is mainly stemmed from suppressing the endothelin (ET-1) pathway associated with a moderate hypoglycemic effect.

METHODS AND MATERIALS

Diabetes for 8 weeks was induced by a single dose of streptozotocin (STZ, 65 mg/kg, i.p.) in rats and treated with RC extracts in either 95%, 70% ethanol or water separately during 5-8th week. The efficacy of extracts was compared with aminoguanidine (AMG).

RESULTS

An increase in albumin and creatinine in 24h urine, blood urea nitrogen (BUN) was found in STZ rats. Oxidative stress was found in renal cortex in association with upregulated plasma ET-1 and mRNA of ETA, decreased MMP 2,9 (matrix matelloproteinases) and increased hydroxyproline.

CONCLUSIONS

The RC without Corni fructus was very effective in alleviating DN and ethanol extracts provided greater effects against water extracts. The efficacy in alleviating DN is attributed to normalizing the activated ET system, oxidative stress and MMP 2,9 in combination with a moderate hypoglycemic activity.