Beneficial effect of Astragalus membranaceus on estimated glomerular filtration rate in patients with progressive chronic kidney disease

Renal protective effects of astragalus root in rat models of chronic kidney disease

BACKGROUND

Astragalus root is a commonly used herb in traditional Chinese medicine. Although renoprotective effects have been reported in some clinical and experimental studies, the details remain unknown.

METHODS

We used 5/6 nephrectomized rats as chronic kidney disease (CKD) models. At 10 weeks, they were divided into four groups, namely, CKD, low-dose astragalus (AR400), high-dose astragalus (AR800), and sham groups. At 14 weeks, they were sacrificed for the evaluation of blood, urine, mRNA expression in the kidney, and renal histopathology.

RESULTS

Kidney dysfunction was significantly improved following astragalus administration (creatinine clearance: sham group; 3.8 ± 0.3 mL/min, CKD group; 1.5 ± 0.1 mL/min, AR400 group; 2.5 ± 0.3 mL/min, AR800 group; 2.7 ± 0.1 mL/min). Blood pressure, urinary albumin, and urinary NGAL levels were significantly lower in the astragalus-treated groups than those in the CKD group. Excretion of urinary 8-OHdG, an oxidative stress marker, and intrarenal oxidative stress were lower in the astragalus-treated groups than those in the CKD group. Furthermore, the mRNA expression of NADPH p22 phox, NADPH p47 phox, Nox4, renin, angiotensin II type 1 receptor, and angiotensinogen in the kidney was lower in the astragalus-treated groups compared with the CKD group.

CONCLUSION

This study suggests that astragalus root slowed CKD progression, possibly through the suppression of oxidative stress and the renin-angiotensin system.

Plant Flavonoids on Oxidative Stress-Mediated Kidney Inflammation

The kidney is susceptible to reactive oxygen species-mediated cellular injury resulting in glomerulosclerosis, tubulointerstitial fibrosis, tubular cell apoptosis, and senescence, leading to renal failure, and is a significant cause of death worldwide. Oxidative stress-mediated inflammation is a key player in the pathophysiology of various renal injuries and diseases. Recently, flavonoids' role in alleviating kidney diseases has been reported with an inverse correlation between dietary flavonoids and kidney injuries. Flavonoids are plant polyphenols possessing several health benefits and are distributed in plants from roots to leaves, flowers, and fruits. Dietary flavonoids have potent antioxidant and free-radical scavenging properties and play essential roles in disease prevention. Flavonoids exert a nephroprotective effect by improving antioxidant status, ameliorating excessive reactive oxygen species (ROS) levels, and reducing oxidative stress, by acting as Nrf2 antioxidant response mediators. Moreover, flavonoids play essential roles in reducing chemical toxicity. Several studies have demonstrated the effects of flavonoids in reducing oxidative stress, preventing DNA damage, reducing inflammatory cytokines, and inhibiting apoptosis-mediated cell death, thereby preventing or improving kidney injuries/diseases. This review covers the recent nephroprotective effects of flavonoids against oxidative stress-mediated inflammation in the kidney and their clinical advancements in renal therapy.

Oral Astragalus Root Supplementation for Mild to Moderate Chronic Kidney Disease: A Self-Controlled Case-Series

In this self-controlled case series, we aimed to investigate the variation in estimated glomerular filtration rate (eGFR) after taking astragalus-containing preparations in patients with mild to moderate chronic kidney disease (CKD) by retrospectively reviewing their charts in our clinic. We set the inclusion criteria as first-visit patients aged 20 years or older presenting to our clinic between 1 October 2014, and 31 June 2019, and who were prescribed astragalus-containing herbal preparations for any reason. We calculated the mean eGFR from the readings taken 6 months before (pre) and after (post) the intake of astragalus-containing preparations for each participant. Among the 37 patients included in our final analysis, we found a statistically significant improvement in the eGFR after prescribing astragalus-containing preparations (pre, 66 ± 12 ml/min/1.73 m² vs. post, 70 ± 14 ml/min/1.73 m²; p < 0.001 by paired t-test). Our results were consistent regardless of age, sex, CKD stage of the participants (G2 or G3), daily dosage of astragalus root, or duration of astragalus-containing preparations. No severe adverse reactions were recorded in the charts of the study participants. Our results suggest that there is eGFR improvement after taking astragalus-containing preparations in mild to moderate CKD cases as reported previously. The findings should be considered with caution due to major limitations such as small sample size without optimum control, short follow-up period, and incomplete data. Further adequately powered and designed studies are needed to confirm the efficacy and safety of the long-term use of astragalus root in patients with mild to moderate CKD.

Molecular Mechanistic Pathways Targeted by Natural Antioxidants in the Prevention and Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) is the progressive loss of renal function and the leading cause of end-stage renal disease (ESRD). Despite optimal therapy, many patients progress to ESRD and require dialysis or transplantation. The pathogenesis of CKD involves inflammation, kidney fibrosis, and blunted renal cellular antioxidant capacity. In this review, we have focused on in vitro and in vivo experimental and clinical studies undertaken to investigate the mechanistic pathways by which these compounds exert their effects against the progression of CKD, particularly diabetic nephropathy and kidney fibrosis. The accumulated and collected data from preclinical and clinical studies revealed that these plants/bioactive compounds could activate autophagy, increase mitochondrial bioenergetics and prevent mitochondrial dysfunction, act as modulators of signaling pathways involved in inflammation, oxidative stress, and renal fibrosis. The main pathways targeted by these compounds include the canonical nuclear factor kappa B (NF-κB), canonical transforming growth factor-beta (TGF-β), autophagy, and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid factor 2-related factor 2 (Nrf2)/antioxidant response element (ARE). This review presented an updated overview of the potential benefits of these antioxidants and new strategies to treat or reduce CKD progression, although the limitations related to the traditional formulation, lack of standardization, side effects, and safety.