Takako Nakagawa

Therapeutic usefulness of Keishi-bukuryo-gan for diabetic nephropathy

Keishi‐bukuryo‐gan is a traditional herbal medicine, which is used clinically as a vascular system disorder‐eliminating drug. In this study, its effect on the progression of diabetic nephropathy in experimental rats was investigated. The diabetic nephropathy model used in this study shows functional and morphological changes of the kidney resembling those seen in patients with diabetic nephropathy. Increased proteinuria and serum urea nitrogen and creatinine levels and decreased creatinine clearance, which are important parameters of renal function, were observed in rats with diabetic nephropathy. Pathological examination of the kidney revealed diffuse, nodular and exudative lesions and arteriolar hyalinosis. The deterioration of renal function was ameliorated in rats treated with Keishi‐bukuryo‐gan for 15 weeks and these results agreed with the renal histological findings. In addition, metabolic abnormalities mediated by persistent hyperglycaemia (the glycation reaction, excessive polyol pathway activity, oxidative stress and lipid metabolic abnormalities) were also observed. However, Keishi‐bukuryo‐gan reduced accumulation of advanced glycation end products, determined by measuring fluorescence, and serum lipid peroxidation, triglyceride and total cholesterol levels dose‐dependently. Thus, this study indicates the potential therapeutic usefulness of Keishi‐bukuryogan for retarding the progression of renal damage and suggests that its beneficial effects were due to its ability to improve metabolic abnormalities associated with diabetes.

Animal model of diabetic nephropathy

Injection of subtotally nephrectomized rats with streptozotocin produced metabolic abnormalities resembling diabetic nephropathy in humans. These abnormalities were hyperglycemia, hypoinsulinemia, azotemia, hypertriglyceridemia and hypercholesterolemia, accompanied with an increase in glycosylated protein. Extraordinary changes in the urinary excretion of glucose and protein were also observed in rats that received streptozotocin treatment after subtotal nephrectomy. In addition, the level of creatinine clearance was significantly decreased. The pathological findings in the kidney of these rats revealed lesions of the glomerular capillary loops, mesangial area and Bowmans capsule. Coagulation was also found in the glomerular capillaries. Our results suggest that this rat model would be useful for studies of diabetic nephropathy.

Effects of green tea tannin on cisplatin-induced nephropathy in LLC-PK1 cells and rats

A study was conducted to clarify whether green tea tannin ameliorated cisplatin‐induced renal injury in terms of lactate dehydrogenase and malondialdehyde leakage from a renal epithelial cell line, swine‐derived LLC‐PK1 cells in culture. Green tea tannin was shown to suppress the cytotoxicity of cisplatin, the suppressive effect increasing with the dose of green tea tannin. The effect of cisplatin was then investigated in rats given green tea tannin for 40 days before cisplatin administration and in control rats given no green tea tannin.

Green tea polyphenols and dietary fibre protect against kidney damage in rats with diabetic nephropathy

In this study we examined the effect of green tea polyphenols (GTP) and partially hydrolysed guar gum (PHGG) as dietary fibre on diabetic nephropathy, using rats that had been subjected to subtotal nephrectomy and injection of streptozotocin. The subtotally nephrectomized rats were subjected to resection of three‐quarters of the kidney. Rats with diabetic nephropathy were divided into four groups: untreated controls, and animals that received GTP (100 mg kg−1 body weight day−1), PHGG (100 mg kg−1 body weight day−1) and GTP plus PHGG (50 mg kg−1 body weight day−1 plus 50 mg kg−1 body weight day−1). After 50 days of administration, attenuation of urinary protein excretion and the morphological changes peculiar to diabetic nephropathy were observed in all three treated groups. Furthermore, the group treated with GTP plus PHGG showed an improvement of kidney weight and serum levels of urea nitrogen, creatinine and creatinine clearance. Hyperglycaemia, as assessed in terms of blood glucose and glycosylated protein levels, was also improved by administration of GTP plus PHGG. On the other hand, GTP administration increased the activity of superoxide dismutase in the kidney to a significant extent. A significant reduction in the total cholesterol concentration was also observed in the PHGG‐treated group. These results suggest that GTP and PHGG could be beneficial as additional therapy in the management of diabetic nephropathy.

A Study on the Effects to Diabetic Nephropathy of Hachimi-jio-gan in Rats

To investigate the effects of Hachimi-jio-gan on diabetic nephropathy, we employed an animal model, rats subjected to sub-total nephrectomy followed by streptozotocin injection, and administered Hachimi-jio-gan orally at a dose of 50, 100 or 200 mg/kg body weight/day for 15 weeks. The administration of Hachimi-jio-gan reduced dose-dependently the elevated blood glucose and urinary protein excretion levels in rats with diabetic nephropathy over the experimental period, whereas it increased creatinine clearance significantly, suggesting that Hachimi-jio-gan would prevent or delay the progression of diabetic nephropathy. In addition, the serum glycosylated protein and urea nitrogen levels were markedly elevated in rats with diabetic nephropathy compared with normal rats, and were significantly reduced by the administration of Hachimi-jio-gan, whereas Hachimi-jio-gan reversed the decrease in the serum albumin level. The serum triglyceride and total cholesterol concentrations were reduced by Hachimi-jio-gan, implying that Hachimi-jio-gan would improve the metabolic disorder of lipids caused by diabetic nephropathy. Moreover, Hachimi-jio-gan inhibited lipid peroxidation in the serum and kidney, which suggests that Hachimi-jio-gan would ameliorate oxidative stress associated with diabetic nephropathy. Furthermore, the disorders of the glucose-dependent metabolic pathway due to this pathological condition were also normalized by the administration of Hachimi-jio-gan through decreases in advanced glycation end-product formation and sorbitol levels in the kidney. Hachimi-jio-gan protected against the development of renal lesions, glomerular sclerosis, tubulointerstitial lesions, mesangial matrix expansion and arteriolar sclerosis, estimated by histopathological evaluation and scoring. This study suggests that Hachimi-jio-gan may be a novel therapeutic approach to improving diabetic nephropathy.

Keishibukuryogan (Gui-Zhi-Fu-Ling-Wan), a Kampo Formula, Decreases Disease Activity and Soluble Vascular Adhesion Molecule-1 in Patients with Rheumatoid Arthritis

An increasing death rate due to cardiovascular disease in patients with rheumatoid arthritis (RA) has been reported. Keishibukuryogan (KBG) is a traditional Chinese/Japanese (Kampo) formula that has been administered to patients with blood stagnation, e.g. thrombotic disease and atherosclerosis. The objective of this study was to evaluate the efficacy of KBG on disease activity and endothelial dysfunction in RA patients. Sixteen RA patients were enrolled and administered KBG (12 g per day) for 12 weeks in addition to continuing other drugs. The disease activity of RA was assessed by modified disease activity scores for 28 joints (DAS28). Plasma levels of adhesion molecules, soluble E-selectin (sE-selectin), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were evaluated. C-reactive protein (CRP), inflammatory cytokines (IL-1β, IL-6 and TNF-α) and lipid peroxide (LPO) were also evaluated. Fourteen patients completed the study. The disease activity of RA, tender joint count, swollen joint count and DAS28 decreased significantly. Among adhesion molecules, only sVCAM-1 decreased significantly. LPO also decreased significantly, whereas CRP and inflammatory cytokines remained unchanged. These results suggest that KBG has insufficient anti-inflammatory or immunomodulating effect but does have a beneficial effect on articular symptoms and a protective effect against endothelial dysfunction in RA patients.

Long-term treatment with Hachimi-jio-gan attenuates kidney damage in spontaneously diabetic WBN/Kob rats

Diabetes mellitus is now the most common cause of end‐stage renal failure. In this study, the effects of Hachimi‐jio‐gan on diabetic kidney damage in spontaneously diabetic WBN/Kob rats were examined. Oral administration of Hachimi‐jio‐gan to WBN/Kob rats for 25 weeks significantly suppressed urinary protein excretion. It did not affect body weight loss or blood glucose levels, whereas it reversed the increase in kidney weight of WBN/Kob rats. Hachimi‐jio‐gan also reduced fibronectin and transforming growth factor β1 (TGF‐β1) protein expression in the renal cortex. Furthermore, renal lipid peroxidation levels of WBN/Kob rats given Hachimi‐jio‐gan were significantly lower than those of untreated controls. Renal superoxide dismutase activity was elevated by Hachimi‐jio‐gan treatment in a dose‐dependent manner. These results suggested that Hachimi‐jio‐gan could prevent diabetic kidney damage by reducing renal oxidative injury and expression of fibronectin and TGF‐β1 proteins, which are all involved in the pathophysiology of diabetic nephropathy.

Influence of green tea polyphenol in rats with arginine-induced renal failure.

To determine whether green tea polyphenol ameliorates the pathological conditions induced by excessive dietary arginine, green tea polyphenol was administered to rats at a daily dose of 50 or 100 mg/kg body weight for 30 days with a 2% w/w arginine diet. In arginine-fed control rats, urinary and/or serum levels of guanidino compounds, nitric oxide (NO), urea, protein, and glucose increased significantly, while the renal activities of the oxygen species-scavenging enzymes superoxide dismutase (SOD) and catalase decreased, compared with casein-fed rats. However, rats given green tea polyphenol showed significant and dose-dependent decreases in serum levels of creatinine (Cr) and urea nitrogen and urinary excretion of Cr, and they exerted a slight reduction of nitrite plus nitrate, indicating that green tea polyphenol reduced the production of uremic toxins and NO. In addition, in arginine-fed rats the urinary urea, protein, and glucose level increases were reversed by the administration of green tea polyphenol. Moreover, in rats given green tea polyphenol the SOD and catalase activities suppressed by excessive arginine administration increased dose-dependently, implying the biological defense system was augmented as a result of free radical scavenging. These results suggest that green tea polyphenol would ameliorate renal failure induced by excessive dietary arginine by decreasing uremic toxin, and NO production and increasing radical-scavenging enzyme activity.

Attenuating Effects of Wen-Pi-Tang Treatment in Rats with Diabetic Nephropathy

Wen-pi-tang is a Chinese prescription used traditionally as a medicine to treat moderate renal failure. In this study, we used rats subjected to subtotal nephrectomy and streptozotocin injection to examine the effects of wen-pi-tang on diabetic nephropathy. Wen-pi-tang was administered at a dose of 50, 100 or 200 mg/kg body weight/day for 15 weeks. Diabetic nephropathy is one of the most serious chronic complications of diabetes mellitus, and renal dysfunction is reflected by proteinuria, decreased creatinine clearance (Ccr) and increased serum urea nitrogen and creatinine (Cr) levels. Wen-pi-tang treatment for 15 weeks resulted in significant reductions of blood glucose and serum urea nitrogen levels, while proteinuria, Ccr and serum Cr levels did not change significantly. Wen-pi-tang also lowered serum triglyceride and thiobarbituric acid-reactive substance levels in a dose-dependent manner. Furthermore, the disorders of the glucose-dependent metabolic pathway due to this pathological condition were normalized by the administration of wen-pi-tang through decreased formation of advanced glycation end-products in the kidney. Wen-pi-tang protected against the development of renal lesions, glomerular sclerosis and mesangial matrix expansion, assessed by histopathological evaluation and scoring. This study suggests that wen-pi-tang treatment could be beneficial in reducing the risk of developing diabetic nephropathy.

Keishibukuryogan ameliorates glucose intolerance and hyperlipidemia in Otsuka Long-Evans Tokushima Fatty (OLETF) rats

Keishibukuryogan, one of the traditional herbal formulations, is used clinically to improve blood circulation. In this study, we examined the effects of keishibukuryogan on glucose and lipids metabolism in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of type 2 diabetes. Forty-five-week-old male OLETF rats were divided into three groups: diabetic control rats given a standard chow; diabetic rats given keishibukuryogan (3%, w/w in chow); diabetic rats given pioglitazone (0.01%, w/w in chow). Oral administration of keishibukuryogan produced significant improvement against impaired glucose tolerance. On the other hand, fasting serum glucose and insulin levels, and the homeostasis index of insulin resistance did not change by keishibukuryogan treatment. Against lipid parameters, keishibukuryogan significantly lowered serum total cholesterol and triglyceride levels, and the hepatic total cholesterol level. Keishibukuryogan treatment also significantly reduced the serum leptin level, but it had no effect on the serum adiponectin level. Additionally, keishibukuryogan showed significant effects on epididymal adipose tissue by decreasing the size of fat cells and on skeletal muscle by reducing TNF-alpha protein content. From these results, it was suggested that keishibukuryogan exerts beneficial effects on the features associated with type 2 diabetes.