[Advances on pathogenesis of acquired peritoneal ultrafiltration failure in peritoneal dialysis]

Peritoneal ultrafiltration failure is a common reason for peritoneal dialysis (PD) withdrawal as well as mortality in PD patients. Based on the three-pore system, inter-cellular small pores and trans-cellular ultra-small pores (aquaporin-1) are mainly responsible for water transfer across the peritoneum. Both small and ultra-small pores-dependent water (free water) transport decline accompanied with time on PD, with more significant decrease in free water, resulting in peritoneal ultrafiltration failure. The reduction of free water transport is associated with fast peritoneal solute transfer, reduced crystalloid osmotic gradient due to increased interstitial glucose absorption, and declined osmotic conductance to glucose resulted from impaired aquaporin-1 function and peritoneal interstitial fibrosis. The decline of small pore-based water is mainly because of fast loss of crystalloid osmotic gradient, decrease of hydrostatic pressure mediated by peritoneal vasculopathy, as well as reduced absolute number of small pores. The current review discusses the advance on pathogenesis of acquired peritoneal ultrafiltration failure in long-term PD.

Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins

In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.

Protective effect of Bu-Zhong-Yi-Qi decoction, the water extract of Chinese traditional herbal medicine, on 5-fluorouracil-induced intestinal mucositis in mice

Intestinal mucositis is a serious toxic side effect of 5-fluorouracil (5-FU) treatment. Bu-Zhong-Yi-Qi decoction (BZYQD), a water extract of Chinese traditional herbal medicine, is widely used in chemotherapy in Asia as an alternative treatment to reduce the side effects of chemotherapy. However, the mechanism is unknown. To evaluate its mechanism, we investigated the effect of BZYQD on 5-FU-induced intestinal mucositis in mice, especially with regard to apoptosis in the intestinal mucosal epithelia. In the present study, mice were divided into three groups: control, 5-FU, and 5-FU + BZYQD. Mice in the 5-FU and 5-FU + BZYQD groups were administered 5-FU (100 mg/kg/day, intraperitoneally) for 6 days, and the mice in the latter group were given BZYQD (8 g/kg/day, intragastrically) beginning 4 days before 5-FU and continuing until the termination of the experiment. Loss in body weight and diarrhea during the 5-FU treatment were significantly attenuated by administration of BZYQD. The morphological signs of intestinal damage, including shortened villi height, crypt destruction, apoptosis, and necrosis, in intestinal mucosal epithelia were also reversed, accompanied by reduced neutrophil infiltration, nitrite levels, and inflammatory factors (tumor necrosis factor α and interleukin 1β) and increased levels of reduced glutathione. These results suggest that BZYQD inhibits 5-FU-induced intestinal mucositis, and this effect may be due to the reduction in apoptosis and necrosis in intestinal mucosal epithelia via the suppression of inflammatory cytokine upregulation. In conclusion, inhibiting cytokine-mediated apoptosis or necrosis can be the molecular mechanism by which BZYQD reduces the gastrointestinal side effects of cancer chemotherapy.

An in vivo and in vitro study: High-dosage Danshen injection induces peripheral vascular endothelial cells injury

Danshen injection, a pharmaceutical dosage form of Danshen, has been widely used in the treatment of coronary heart diseases, myocardial infarction, and hypertension. With more and more adverse drug reactions linked with Danshen injection, its safety comes under suspicion. To evaluate its safety, mice were divided into four groups: vehicle, low-, middle-, and high-Danshen group, and each group was intravenously administered with Danshen injection at a dose of 0, 0.64, 1.55, and 5.76 g/kg/day for 5 days, respectively (the low dosage was the recommended clinical dosage, the middle dosage was the most commonly used higher dosage, and the high dosage was the highest dosage used in clinic). Peripheral vascular toxicity wasn't observed in the low-dosage group, elevated serum endothelin-1 (ET-1) was observed in the middle-dosage group; and more peripheral vascular toxicities like increased vascular leakage, elevated serum nitrate and ET-1, and vascular endothelial cells apoptosis were detected in the high-dosage group. In vitro study, low-concentration Danshen injection showed protective effect to human umbilical vein endothelial cells (HUVECs), while high concentration displayed strong cytotoxic effects, including increase in nitric oxide and ET-1 production, inhibition of cell viability, and apoptosis induction. Further, the HUVECs' apoptosis induced by high-concentration Danshen injection was found along with the induction of reactive oxygen species. In conclusion, these results suggest that Danshen injection is nontoxic in its recommended clinical dosage, and the 2.4-fold as the recommended clinical dosage might be the highest safety dosage in clinic treatment. In addition, Danshen injection is a potential vascular toxic drug in its high dosage and shouldn't be used far beyond its recommended dosage in clinic treatment.

Efficacy of chromium(III) supplementation on growth, body composition, serum parameters, and tissue chromium in rats

Chromium(III) is often claimed to have a positive effect on body composition, while the responses in researches with supplementation of different chemical form of chromium are various and inconsistent. We have studied the effects of 6 weeks of treatment with three different forms of chromium (300 mug/kg) as chromium chloride, chromium tripicolinate, and chromium nanocomposite (CrNano) on growth, body composition, serum parameters, and tissue chromium in rats. The supplementation of CrNano significantly increased average daily gain, food efficiency, and lean body mass and decreased fat mass and body fat proportion and serum levels of glucose, urea nitrogen, triglyceride, and insulin. Chromium contents in liver, kidney, and hind leg muscle were increased significantly with the addition of CrNano in diet. The results indicate that chromium nanocomposite has higher efficacy on growth and body composition compared to the traditional chromium agents.

Transfer of lead via placenta and breast milk in human

The mean lead levels in the maternal blood, cord blood, breast milk and placental tissue, were 0.63 mumol/L (13.2 micrograms/dL), 0.33 mumol/L (6.90 micrograms/dL), 4.74 micrograms/L and 0.86 mumol/kg (17.85 micrograms/100 g) respectively for 165 parturient women occupationally non-exposed to lead in 2 hospitals in Shanghai. No significant difference was found between maternal age groups for these indicators. However, the lead levels in the cord blood and breast milk increased with the lead level in the maternal blood, with coefficient of correlation of 0.714 (P < 0.0001) and 0.353 (P < 0.01) respectively. The mean concentration of lead in breast milk for 12 occupationally lead exposed women was 52.7 micrograms/L, which was almost 12 times higher than that for the occupationally non-exposed population. These results suggested that transfer of lead via placenta prenatally and breast milk postnatally were possible and might pose a potential health hazard to the fetuses and the neonates.