Geniposide alleviates VEGF-induced angiogenesis by inhibiting VEGFR2/PKC/ERK1/2-mediated SphK1 translocation

BACKGROUND

Rheumatoid arthritis (RA) is an angiogenesis-dependent disease caused by the imbalance of pro- and anti-angiogenic factors. More effective strategies to block synovial angiogenesis in RA should be studied. Geniposide (GE), a natural product isolated from the fruit of Gardenia jasminoides Ellis (GJ), is reported to have anti-inflammatory, anti-angiogenic and other pharmacological effects. However, the underlying mechanism through which GE affects synovial angiogenesis in RA remains unclear.

PURPOSE

In this research, we aimed to elucidate the effect and potential mechanisms of GE on angiogenesis in RA.

MATERIALS AND METHODS

Synovial angiogenesis in patients with RA and a rat model of adjuvant arthritis (AA) was detected by hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), and western blottiing. The biological functions of vascular endothelial cells (VECs) and sphingosine kinase 1 (SphK1) translocation were checked by CCK-8, EdU, Transwell, tube formation, co-immunoprecipitation assays, and laser scanning confocal microscopy. The effect of the SphK1 gene on angiogenesis was assessed by transfection of SphK1-siRNA in cells and mices. The effect of GE on VEGF-induced angiogenesis was measured by Matrigel plug assay in a mouse model of AA.

RESULTS

GE effectively inhibited synovial angiogenesis and alleviated the disease process. SphK1, as a new regulatory molecule, has a potentially important relationship in regulating VEGF/VEGFR2 and S1P/S1PR1 signals. SphK1 translocation was activated via the VEGFR2/PKC/ERK1/2 pathway and was closely linked to the biological function of VECs. GE significantly reduced SphK1 translocation, thereby ameliorating the abnormal biological function of VECs. Furthermore, after transfection of SphK1 siRNA in VECs and C57BL/6 mice, silencing SphK1 caused effectively attenuation of VEGF-induced VEC biological functions and angiogenesis. In vivo, the Matrigel plug experiment indicated that GE significantly inhibited pericyte coverage, basement membrane formation, vascular permeability, and fibrinogen deposition.

CONCLUSIONS

Our findings suggest that GE inhibited VEGF-induced VEC biological functions and angiogenesis by reducing SphK1 translocation. Generally, studies have revealed that GE down-regulated VEGFR2/PKC/ERK1/2-mediated SphK1 translocation and inhibited S1P/S1PR1 signaling activation, thereby alleviating VEGF-stimulated angiogenesis. The above evidences indicated that angiogenesis inhibition may provide a new direction for RA treatment.

Comparison of tranexamic acid pharmacokinetics after intra-articular and intravenous administration in rabbits

Tranexamic Acid (TXA) is commonly administered in total knee arthroplasty for reducing blood loss. There has been a growing interest in the topical use of TXA except intravenous use for prevention of bleeding in TKA. The aim of this study was to develop and validate a HPLC-MS method to detect TXA and apply to compare the pharmacokinetic profile of TXA after intravenous (IV) and topical intra-articular (IA) application of TXA at a dose of 20 mg/kg in rabbits. In order to prove intra-articular administration is better than that of intravenous administration from the point of rabbit pharmacokinetic. Two groups of rabbits (n=6/group) respectively received TXA intra-articularly or intravenously. Blood samples were collected at scheduled time. The concentration of TXA in plasma was determined by a validated HPLC-MS method. Excellent linearity was found between 0.015 and 70.0μg/ml with a lower limit of quantitation (LLOQ) of 0.015μg/ml (r>0.99); moreover, all the validation data including accuracy and precision (intra- and inter-day) were all within the required limits. The pharmacokinetic parameters in IA and IV group were: C_max: 30.65±3.31 VS 54.05± 6.21μg/ml (p<0.01); t_1/2: 1.26±0.05 VS 0.68±0.13h (p<0.05); AUC_0-t: 42.98±7.73 VS 23.39±4.14μg/ml• h (p<0.01), time above the minimum effective concentration (%T > MEC): 1.5-2.2 VS 0.7-1.2h (p<0.05). HPLC-MS method is suitable for TXA pharmacokinetic studies. The results demonstrated that topical intra-articular application of TXA showed a reduced peak plasma concentration and prolonged therapeutic drug level compared with intravenous TXA from the point of rabbit pharmacokinetic.

Female-specific vs conventional knee prostheses after total knee arthroplasty: A meta-analysis

AIM: To study whether female-specific prostheses are superior to conventional prostheses after total knee arthroplasty (TKA) by conducting this meta-analysis to evaluate the effects of the 2 different designs.

METHODS: A systematic electronic search was conducted in the databases of PubMed, EMBASE and the Cochrane Library for prospective and retrospective trials. Meta-analysis was performed for the outcomes, including range of motion (ROM), Knee Society score, Hospital for Special Surgery scores (HSS) and complications including deep infection, manipulation under anesthesia (MUA), revisions, anterior knee pain, deep vein thrombosis and overhang rate. Meta-analysis was conducted where applicable. Weighted mean difference (WMD) and odds ratio were calculated according to study type.

RESULTS: Seven studies including 1174 knees were eligible for data extraction and pooled analysis. The overhang rate of female-specific prostheses was significantly lower than the conventional ones (WMD, 3.25; 95%CI: 0.00-0.27; P = 0.001). ROM in the female-specific prostheses group after TKA tended to be greater than the conventional prostheses group; however, with insignificant difference (WMD, 2.48; 95%CI: -0.83-5.78; P = 0.14). HSS (WMD, 0.48; 95%CI: -1.45-0.88; P = 0.63) and complications including deep infection (WMD, 0.39; 95%CI: 0.19-3.08; P =0 .70), MUA (WMD, 1.53; 95%CI: 0.02-1.61; P = 0.13) and revisions (WMD, 0.55; 95%CI: 0.07-4.34; P = 0.13) were all comparable between the two groups with at least 1 year follow-up. Other indexes were revealed to be similar between the two treatments with a descriptive analytical method.

CONCLUSION: Although the overhang rate is lower with female-specific prostheses, the current evidence does not support that female-specific prostheses outweigh conventional ones after TKA.