Torao Ishida

The structure of pyridinoline, a collagen crosslink

Abstract Pyridinoline is an amino acid isolated from collagen and probably serves as a crosslink in collagen fiber. This compound was isolated on a large scale from bovine bone and investigated by 1 H-nmr and 13 C-nmr spectroscopy, mass spectroscopy and chemical degradation. The structure is proposed on the basis of these data.

Antidiabetic activity of a xanthone compound, mangiferin

Mangiferin (MF) isolated from Anemarrhena asphodeloides Bunge rhizome, was tested for antidiabetic activity in KK-Ay mice, an animal model of type-2 diabetes. MF lowered the blood glucose level of KK-Ay mice 3 weeks after oral administration (p < 0.01). However, no effect on the blood glucose level in normal mice was seen, indicating that MF could be useful in treating type-2 diabetes. In addition, MF improved hyperinsulinemia and, on insulin tolerance test, reduced blood glucose levels of KK-Ay mice. From these findings, it seems likely that MF exerts its antidiabetic activity by decreasing insulin resistance.

HYPOXIA-INDUCED ASTROCYTES PROMOTE THE MIGRATION OF NEURAL PROGENITOR CELLS VIA VASCULAR ENDOTHELIAL FACTOR, STEM CELL FACTOR, STROMAL-DERIVED FACTOR-1α AND MONOCYTE CHEMOATTRACTANT PROTEIN-1 UPREGULATION IN VITRO

1 The aim of the present study was to examine if and how rat hypoxia‐induced astrocytes affect the migration of neural progenitor cells (NPC) and to investigate the expression patterns of some chemokines, such as vascular endothelial growth factor (VEGF), stem cell factor (SCF), stromal‐derived factor‐1α (SDF‐1α), fractalkine and monocyte chemoattractant protein‐1 (MCP‐1) in hypoxia‐induced astrocytes and their contribution to NPC migration in vitro. 2 Costar Transwell inserts were used for the chemotaxis assay and quantified changes in the chemokines mRNA for between 0 h and 24 h posthypoxia were tested using real‐time quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis. The results showed that the chemotaxis of astrocyte cells exposed to hypoxia for 18 h reached a peak value, whereas the chemotaxis of astrocytes exposed to hypoxia for 24 h began to decrease compared with those exposed to hypoxia for 18 h. Hypoxia upregulated chemokine VEGF, SCF, SDF‐1α and MCP‐1 expression in a time‐dependent manner but downregulated fractalkine expression in astrocytes. In addition, the time points of the peak expressions for VEGF, SCF, SDF‐1α and MCP‐1 were similar to the time point of maximum NPC migration. 3 Specific inhibitors that block the binding of specific chemokines to its receptors were used for analysing the contribution of the chemokine to NPC migration. When VEGF, SCF, SDF‐1α and MCP‐1 were each inhibited independently, NPC migration was reduced. When they were inhibited together, NPC migration was obviously inhibited compared with both the control and single‐block cultures, which implies that the migratory effect of hypoxia‐induced astrocytes was synergetic by several chemokines. 4 In conclusion, we demonstrated the time‐dependent manner of NPC migration promotion by hypoxia‐induced astrocytes. We also provide evidence that soluble factors, such as VEGF, SCF, SDF‐1α and MCP‐1, released from astrocytes, direct the migration of NPC under hypoxic circumstances. Given that astrocytes were activated to all hypoxia–ischaemia diseases, these results indicate an important role for astrocytes in directing NPC replacement therapy in the central nervous system.

Drinking hydrogen water ameliorated cognitive impairment in senescence-accelerated mice.

Hydrogen has been reported to have neuron protective effects due to its antioxidant properties, but the effects of hydrogen on cognitive impairment due to senescence-related brain alterations and the underlying mechanisms have not been characterized. In this study, we investigated the efficacies of drinking hydrogen water for prevention of spatial memory decline and age-related brain alterations using senescence-accelerated prone mouse 8 (SAMP8), which exhibits early aging syndromes including declining learning ability and memory. However, treatment with hydrogen water for 30 days prevented age-related declines in cognitive ability seen in SAMP8 as assessed by a water maze test and was associated with increased brain serotonin levels and elevated serum antioxidant activity. In addition, drinking hydrogen water for 18 weeks inhibited neurodegeneration in hippocampus, while marked loss of neurons was noted in control, aged brains of mice receiving regular water. On the basis of our results, hydrogen water merits further investigation for possible therapeutic/preventative use for age-related cognitive disorders.

Eucommia Leaf Extract (ELE) Prevents OVX-Induced Osteoporosis and Obesity in Rats

The cortex of Eucommia ulmoides Oliver is widely used to treat kidney deficiency in traditional Chinese medicine. Its leaves have recently been reported to have anti-obesity properties in metabolic syndrome-like rat models. Due to a sharp decline in estrogen production, obesity, together with osteoporosis, are common problems in postmenopausal women. In this study, we examined the potential effect of Eucommia leaf extract (ELE) in preventing osteoporosis and obesity induced by ovariectomy (OVX). Forty-six female Wistar rats were divided into six groups: Sham-Cont, OVX-Cont, and four OVX groups administered estradiol and different concentrations of ELE 1.25%, ELE 2.5%, and ELE 5%. Treatments were administered after ovariectomy at six weeks of age and continued for 12 weeks. OVX induced a significant decrease in the bone mineral density (BMD) of the lumbar, femora, and tibiae, together with a marked increase in body mass index (BMI). The administration of 5% ELE led to a significant increase in tibial and femoral BMD, as well as significantly increased bone-strength parameters when compared with OVX-Cont rats. According to the suppressed Dpd and increased osteocalcin concentrations in ELE 5% rats, we suggest that varying proportions of bone formation and bone absorption contributed to the enhanced BMD in the femora and tibiae. In addition, significant decreases in body weight, BMI and fat tissue in 5% ELE rats were also observed. These results suggest that ELE may have curative properties for BMD and BMI in OVX rats, and could provide an alternative therapy for the prevention of both postmenopausal osteoporosis and obesity.

Possible involvement of histamine, dopamine, and noradrenalin in the periaqueductal gray in electroacupuncture pain relief

Acupuncture and electroacupuncture are used in pain relief; however, the mechanism underlying the analgesic effect of acupuncture is unclear. Several lines of evidence propose that the periaqueductal gray (PAG), which is one of the regions that contributes to the endogenous pain inhibitory system, is involved in the analgesic effect of acupuncture, and the region receives several neural projections such as histamine and noradrenalin and contains the dopamine cell bodies. The current study examined the effects of electroacupuncture at Zusanli (ST36) and Shangjuxu (ST37) acupoints, which are used for clinical pain control, on the release of neurotransmitters in the PAG in rats. Histamine and dopamine release was increased after pain stimulus, while the changes were completely abolished by electroacupuncture. Pain stimulus had no effect on noradrenalin release, but electroacupuncture increased its release. These findings indicate that acupuncture at Zusanli and Shangjuxu exerts an antinociceptive effect via the activation of neurons in the PAG and that the histaminergic, dopaminergic, and noradrenalinergic systems in the PAG are related to electroacupuncture-induced pain relief.

Management of Diabetes and Its Complications with Banaba (Lagerstroemia speciosa L.) and Corosolic Acid

Banaba (Lagerstroemia speciosa L.) extracts have been used for many years in folk medicine to treat diabetes, with the first published research study being reported in 1940. This paper summarizes the current literature regarding Banaba and its constituents. The hypoglycemic effects of Banaba have been attributed to both corosolic acid as well as ellagitannins. Studies have been conducted in various animal models, human subjects, and in vitro systems using water soluble Banaba leaf extracts, corosolic acid, and ellagitannins. Corosolic acid has been reported to decrease blood sugar levels within 60 min in human subjects. Corosolic acid also exhibits antihyperlipidemic and antioxidant activities. The beneficial effects of Banaba and corosolic acid with respect to various aspects of glucose and lipid metabolism appear to involve multiple mechanisms, including enhanced cellular uptake of glucose, impaired hydrolysis of sucrose and starches, decreased gluconeogenesis, and the regulation of lipid metabolism. These effects may be mediated by PPAR and other signal transduction factors. Banaba extract, corosolic acid, and other constituents may be beneficial in addressing the symptoms associated with metabolic syndrome, as well as offering other health benefits.

β-Blocker and Other Analogous Treatments that Affect Bone Mass and Sympathetic Nerve Activity in Ovariectomized Rats

We investigated whether treatments with beta-blockers or other administrations that have similar actions to beta-blockers, such as Chinese herbs or needling, were effective in treating osteoporosis induced by ovariectomy (OVX). Female Wister rats were divided into five groups: a sham-operated control group treated with vehicle (Sham, n = 8), an ovariectomized (OVX) group treated with vehicle (Model, n = 8), an OVX group administered with propranolol (Pro, n = 10), an OVX group administered an ethanol extract of Fructus Citri Sarcodactylis (Fcs, n = 9), and an OVX punctured at Sanyinjiao (SP-6) and Neiguan (PC-6) (Needling, n = 8). The treatment started when rats were 12 weeks old and continued for 24 weeks. Serum osteocalcin and urinary deoxypyridinoline (Dpd) levels were upregulated in rats in response to OVX, together with a significantly decreased BMD and trabecular bone area. The Pro, Fcs and Needling treatment improved the decreased BMD and the trabecular area, increased the trabecular number, lowered the trabecular separation to some extent as well as significantly depressed the urinary Dpd levels (p < 0.05). The bone formation markers, such as the mineralizing surface, mineral apposition rate and bone formation rate were not significantly changed, along with a slightly higher trend of osteocalcin levels when compared with the Model rats. The slower heart rate and lower plasma NE levels in these therapeutic groups were also found. Our results suggested that propranolol, Fcs and needling on Sanyinjiao (SP-6) and Neiguan (PC-6) may improve the bone mass of OVX rats, and it provides an alternative and potential therapy for the prevention of postmenopausal osteoporosis.

The Effect of the Major Components of Fructus Cnidii on Osteoblasts In Vitro

In traditional Chinese medicine, the cause of weak bones or bone loss is generally regarded as a result of kidney deficiency. Fructus Cnidii (FC), which is also known as She-Chuang-Zi, is a traditional herb that has been claimed to have kidney warming effects that invigorate Yang. In this study, we tried to determine the bone production-inducing effect of FC on osteoblastic cells in vitro using osthole, the main component of FC. Osteoblasts were isolated from neonatal Sprague-Dawley rat calvaria using the tissue piece culture method and treated with various concentrations of osthole ranging from 2.5 to 640 microg/mL, together with a blank control. Cell proliferation, alkaline phosphatase (ALP) activity, and bone nodules were measured. The cells were examined by hematoxylin-eosin staining, the Gomori Calcium-Cobalt method and immunofluorescent staining. The 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (or MTT) assay, ALP assay, and bone nodule results indicated significantly enhanced osteoblastic proliferation and differentiation at concentrations of osthole ranging from 40 to 320 microg/mL. Concentrations lower than 40 microg/ mL seemed less effective, and cytotoxicity to osteoblasts was observed at concentrations higher than 320 microg/mL. These results indicate that osthole is effective at inducing osteoblastic bone formation through the up-regulation of ALP activity. FC is a Chinese herb used to treat lumbar pain in clinical practice. Further studies concerning the effects and mechanism of osthole on osteoporotic patients and animals should be performed, as these studies may lead to the development of a drug treatment for osteoporosis in the future.

Antidiabetic effect of nitobegiku in KK-Ay diabetic mice.

In the past, nitobegiku (the herb of Tithonia diversifolia (Hemsl) A. Gray) has been used as a medicinal plant for diabetes. Antidiabetic effect of the water extract of Nitobegiku (NG) was investigated in KK-Ay-mice--one of the animal models of type 2 diabetes. NG (1,500 mg/kg body weight) reduced the blood glucose of KK-Ay mice from 509 +/- 22 mg/dl to 340 +/- 14 mg/dl (p < 0.001) and also lowered the plasma insulin (p < 0.05) 7 hours after single oral administration. No change in blood glucose of NG-treated normal mice (ddY) was seen. These results support that NG improve glucose metabolism by reducing insulin resistance. Therefore, NG may be useful for treatment of type 2 diabetes.