Increased miR-155-5p expression in dermal mesenchymal stem cells of psoriatic patients: comparing the microRNA expression profile by microarray.

Mesenchymal stem cells (MSCs) have pleiotropic immuno-modulatory effects and pro-angiogenic ability, leading to the presumption that MSCs may be involved in the pathogenesis of many inflammatory or autoimmune disorders, including psoriasis. In a previous study, we reported the specific gene expression profile of dermal MSCs from psoriasis. Inflammation- and angiogenesis-related genes, such as lipopolysaccharide-induced tumor necrosis factor-alpha transcription factor (LITAF), dual-specificity protein phosphatase 1 (DUSP1), vascular endothelial growth factor α (VEGFα), and insulin-like growth factor-binding protein-5 (IGFBP5), are abnormally expressed in psoriatic dermal MSCs. As a key regulator of gene expression, miRNA are involved in a wide variety of biological processes; in fact, several miRNAs have been implicated in the development and progression of inflammatory or autoimmune disorders. In this study, we compared the miRNA expression profiles of dermal MSCs from patients with psoriasis to those in MSCs from normal individuals by microarray, and found that the pro-inflammatory miRNA miR-155 was significantly overexpressed in psoriatic MSCs (2.44 fold, P < 0.001). Additionally, the expression of miR-155 target gene TAB2 (8.47 ± 1.55 vs 6.38 ± 2.10, P < 0.01,) and the downstream gene iNOS (5.26 ± 2.58 vs 3.73 ± 1.89, P < 0.05) was found to be inhibited in psoriatic dermal MSCs by real-time PCR. Therefore, we speculated that the elevation in miR-155 levels may be an indicator of, or a key regulatory pathway in, the pathogenesis of psoriasis, resulting in functionally impaired dermal MSCs.

Stability of daphnoretin in vitro.

The stability of daphnoretin in sodium phosphate buffers at different pH and temperature, and in different biological samples at 37 degrees C was investigated using HPLC with UV detector set at 345 nm. Daphnoretin degraded rapidly in alkaline environment and was stable in acidic environment. Daphnoretin was stable in simulated gastrointestinal liquid, stomach contents, gastric mucosa and colon contents; it was unstable in plasma, liver homogenates, small intestine contents, small intestinal mucosa and blind gut contents. The stability of daphnoretin in plasma and other biomaterials could have a significant impact on its absorption.

Hollow fiber liquid-phase microextraction for the determination of nimesulide in human plasma and its application to a pharmacokinetic study.

A hollow fiber liquid-phase microextraction (HF-LPME) method in combination with HPLC-UV for the determination of nimesulide in human plasma was developed and validated. A small volume of dihexyl ether contained within a polypropylene hollow fiber was used for the extraction of nimesulide from acidified plasma solutions. Factors affecting the extraction efficiency were optimized and discussed. With HPLC-UV as the end analysis technique, the procedure was validated for nimesulide in the concentration range of 50-5000 ng/mL. The intra- and inter-assay precisions were less than 9.1%, and accuracy was within 3.2%. The lower limit of quantification (LLOQ) was 50 ng/mL. Enrichment factor from 144-fold to 156-fold was achieved at three quality control (QC) concentrations. The mean extraction recovery was greater than 41.2%. This method was successfully applied for the evaluation of pharmacokinetics of nimesulide after single oral doses of 100 mg nimesulide to six healthy Chinese volunteers.