PiT-2, a type III sodium-dependent phosphate transporter, protects against vascular calcification in mice with chronic kidney disease fed a high-phosphate diet.

PiT-2, a type III sodium-dependent phosphate transporter, is a causative gene for the brain arteriolar calcification in people with familial basal ganglion calcification. Here we examined the effect of PiT-2 haploinsufficiency on vascular calcification in uremic mice using wild-type and global PiT-2 heterozygous knockout mice. PiT-2 haploinsufficiency enhanced the development of vascular calcification in mice with chronic kidney disease fed a high-phosphate diet. No differences were observed in the serum mineral biomarkers and kidney function between the wild-type and PiT-2 heterozygous knockout groups. Micro computed tomography analyses of femurs showed that haploinsufficiency of PiT-2 decreased trabecular bone mineral density in uremia. In vitro, sodium-dependent phosphate uptake was decreased in cultured vascular smooth muscle cells isolated from PiT-2 heterozygous knockout mice compared with those from wild-type mice. PiT-2 haploinsufficiency increased phosphate-induced calcification of cultured vascular smooth muscle cells compared to the wild-type. Furthermore, compared to wild-type vascular smooth muscle cells, PiT-2 deficient vascular smooth muscle cells had lower osteoprotegerin levels and increased matrix calcification, which was attenuated by osteoprotegerin supplementation. Thus, PiT-2 in vascular smooth muscle cells protects against phosphate-induced vascular calcification and may be a therapeutic target in the chronic kidney disease population.

Effect of quercetin on P-glycoprotein transport ability in Chinese healthy subjects.

OBJECTIVES: The aim of this study was to investigate the effect of quercetin on P-glycoprotein (P-gp) transport ability in vivo. SUBJECTS/METHODS: Genotype data were available from a total of 165 health volunteers. An open, randomized, two-period crossover clinical trial was performed in eighteen subjects with different MDR1 3435 C/T genotypes. All subjects took 500 mg quercetin or placebo daily from 1st to 13th day or from 43 st to 55th day, and 100 mg talinolol was given at the 14th or 56th day. The washout period is 28 days. RESULTS: In this study, we found the values of area under the curve (AUC)0-48 h, AUC0-∞ and Cmax of talinolol in all subjects significantly decreased (6496.6 ± 2389.9 vs 7809.5 ± 2386.8 ng.h/ml, P=0.04), (8414.7 ± 344.8 vs 10478.2 ± 4195.4 ng.h/ml, P=0.03), (412.9 ± 132.6 vs 543.3 ± 97.9 ng.h/ml, P=0.01) after administration of quercetin, respectively. There were no significant differences in tmax and t1/2 of talinolol. The results also showed AUC0-48 h (5598.6 ± 2202.1 vs 8229.4 ± 1491.7 ng.h/ml, P=0.02) and AUC0-∞ (7110.0 ± 3437.0 vs 12681.2 ± 4828.2 ng.h/ml, P=0.01) of talinolol to be significantly decreased in MDR1 3435 TT individuals administered of quercetin. The Cmax of talinolol in MDR1 3435 TT (382.4 ± 149.1 vs 584.9 ± 115.2 ng/ml, P=0.04) and MDR1 3435 CT (383.5 ± 104.9 vs 554.6 ± 80.6 ng/ml, P=0.01) individuals significantly decreased after the administration of quercetin. CONCLUSIONS: Quercetin significantly induced the activity of P-gp and this induced effect was more obvious in MDR1 3435 TT individuals.

Protective activity of the ethanol extract of Cynanchum paniculatum (BUNGE) Kitagawa on treating herpes simplex encephalitis.

To date there has been no valid treatment for herpes simplex encephalitis (HSV). This study explores the protective activity of ethanol extract of Cynanchum paniculatum (bunge) kitagawa for treatment of HSV. Cell models and animal models were established and divided into 4 groups: normal group, virus group, cynanchum paniculatum group and Dexamethasone group. Flow cytometry was employed to detect apoptosis of cell model and TUNEL assay was chosen to detect apoptosis of animal tissues. The survival time of the animal models was observed. ELISA was used to measure TNF-alpha expression and the Greiss method to measure Nitric Oxide (NO) expression in the mouse brain. As a result, it was found that extract of Cynanchum paniculatum can improve the survival rate of HSV-infected mice. The extract could prevent apoptosis in the neuron cell model and reduce apoptosis rate in brain tissue after HSV infection. With the extract intervention, TNF-alpha and NO levels in brain tissue were significantly decreased in the animal model. In conclusion, the extract of Cynanchum paniculatum can prevent HSV-inducing impairment in the cell and animal model of HSE.

Smooth muscle cells deficient in osteopontin have enhanced susceptibility to calcification in vitro.

OBJECTIVE: Vascular calcification is an actively regulated process, correlating with cardiovascular morbidity and mortality especially in patients with diabetes and chronic renal diseases. Osteopontin (OPN) is abundantly expressed in human calcified arteries and inhibits vascular calcification in vitro and in vivo. How OPN functions in vascular calcification, however, is less clear. METHODS: Smooth muscle cells (SMCs) were isolated from aortas of OPN knock-out (OPN-/-) and wild type (OPN+/+) mice. RESULTS: OPN-/- SMCs were identical to OPN+/+ SMCs in morphology and stained positively for SM lineage proteins, desmin, smooth muscle alpha-actin and SM22alpha. No spontaneous calcification was observed in OPN-/- SMCs under normal culture conditions or in medium containing 1%, 3%, or 5% fetal bovine serum. However, when cultured in medium containing elevated concentrations of inorganic phosphate, an inducer of vascular calcification, a significantly higher calcification was observed in OPN-/- SMCs compared to OPN+/+ SMCs that, in response to elevated phosphate, synthesized and secreted OPN into the culture. Finally, retroviral transduction of mouse OPN cDNA into OPN-/- SMCs rescued the calcification phenotype of the cells. CONCLUSION: These results are the first to demonstrate an inhibitory role of endogenously produced OPN on SMC calcification, suggesting a novel feedback mechanism where OPN produced locally by the SMCs may serve as an important inducible inhibitor of vascular calcification.

Reversal of cancer multidrug resistance by tea polyphenol in KB cells.

Tea polyphenols, (-)-epigallocatechin gallate in particular, were examined for their modulating effects on the drug resistance KB-A-1 cells and drug sensitive KB-3-1 cells. Both KB-3-1 and KB-A-1 cells were equally sensitive to tea polyphenol and (-)-epigallocatechin gallate. When 10 microgram/ml (-)-epigallocatechin gallate or 40 microgram/ml tea polyphenol were present simultaneously with doxorubicin, the IC50 of doxorubicin on KB-A-1 cells decreased from 10.3 +/- 0.9 microgram/ml to 4.2 +/- 0.2 or 2.0 +/- 0.1 microgram/ml. Tea polyphenol and (-)-epigallocatechin gallate enhanced the cytotoxicity of doxorubicin on KB-A-1 cells by 5.2 and 2.5 times, respectively, but did not show a modulating effect on KB-3-1 cells. Both tea polyphenol and (-)-epigallocatechin gallate showed reversal effects on the multidrug resistance phenotype.

[A preliminary study of two Chinese herbs protective tablets on some Chinese traditional medicines].

The protective action of 2 tablets of Chinese herb to 5 Chinese traditional medicines against harm of insects and mildews was tested. It was found that 2 tablets have a obvious effects of insect-repellency and mouthproof in the test with Homalomena occulta and Prunus armeniaca, the bore in the medicinal materials was decreased 94.95% and 95.55% respectively than that of check. The tablets have some effects of mildewproof in the test with Tussilago farfara.

Development of bovine IVF oocytes cultured in medium supplemented with a nitric oxide scavenger or inhibitor in a co-culture system.

Bovine IVF oocytes were cultured in modified bovine embryo culture medium (mBECM) supplemented with either a nitric oxide (NO) scavenger, hemoglobin (Hb, 1 microg/mL) and/or a NO synthesis inhibitor, L(omega)-nitro-L-arginine methyl ester (L-NAME, 1 or 1000 nM) in a cumulus-granulosa cell co-culture system. In Experiment 1, a total of 1,675 cumulus-oocytes complexes was collected for 7 mo and cultured to the blastocyst stage in mBECM with or without Hb after IVM and IVF. There were significant (P<0.0024) model effects of Hb addition and month of oocyte collection on embryo development. A significant (P<0.0023) monthly variation was detected in all developmental stages. However, addition of Hb to mBECM consistently enhanced embryo development to the blastocyst stage over all months. No statistical differences were found in the interaction between Hb addition and month except for the cleavage rate. Overall, a greater percentage of oocytes developed to the 8-cell (P<0.0459), 16-cell (P<0.001), morula (P<0.0013) and blastocyst (P<0.0024) stages after the addition of Hb. In Experiment 2, addition of L-NAME to mBECM supplemented with Hb did not further stimulate prehatched development. In conclusion, the promoting effect of Hb on in vitro development of embryos is highly repeatable over an extended period of time.

Activation of dopamine D4 receptor inhibits an L-type calcium current in cerebellar granule cells.

The functions of the D4 receptor, a newly cloned D2-like receptor, as well as the identity of cells expressing it, are still poorly defined. Using quantitative polymerase chain reaction we detected the messenger RNA of the D4, but not other D2-like receptor, in cultured granule cells from neonatal rat cerebellum. In these neurons, dopamine reduced high-voltage-activated calcium current, with a pharmacology corresponding to that of the D4 receptor. The response declined from one to three days, when calcium currents were mostly sensitive to nifedipine, to 15 days, when nifedipine-insensitive calcium currents were also present and D4 receptor messenger RNA had declined. The dopamine response was abolished after pretreatment of the cells by pertussis toxin, was potentiated and made irreversible by infusion of guanosine 5'-O-(3-thiotriphosphate) but persisted in the presence of cyclic AMP and isobutylmethylxanthine. These results indicate the presence in the neonatal cerebellum of a functional D4 receptor inhibiting an L-type calcium current, an action involving a Gi/Go protein but independent from adenylate cyclase inhibition.