Fucoidan-based micelles as P-selectin targeted carriers for synergistic treatment of acute kidney injury.

Acute kidney injury (AKI) is a life-threatening disease without effective treatment. The utilization of curcumin (Cur) for the treatment of AKI is still facing challenges due to its poor water-solubility and low bioavailability. Herein, kidney-targeted octenyl succinic anhydride-grafted fucoidan loaded with Cur (OSA-Fucoidan/Cur) was fabricated for synergistic treatment of AKI. It was found that OSA-Fucoidan/Cur micelles had a sustained drug release behavior and excellent physicochemical stability. Cellular uptake studies demonstrated that the specific binding between fucoidan and P-selectin overexpressed on H2O2-stimulated HUVECs contributed to the higher internalization of OSA-Fucoidan/Cur micelles by the cells. In addition, OSA-Fucoidan micelles exhibited an ideal kidney-targeted characteristic in lipopolysaccharide (LPS)-induced AKI mice. In vivo studies showed that the combination of Cur and OSA-Fucoidan endowed the OSA-Fucoidan/Cur micelles with synergistically anti-inflammatory and antioxidant abilities, thereby largely enhancing the therapeutic efficacy of AKI. Therefore, OSA-Fucoidan/Cur micelles may represent a potential kidney-targeted nanomedicine for effective treatment of AKI.

Inhibition of inflammatory injure by polysaccharides from Bupleurum chinense through antagonizing P-selectin.

P-selectin-mediated adhesion between endothelium and neutrophils is a crucial process leading to acute inflammatory injure. Thus, P-selectin has been considered as promising target for therapeutics of acute inflammatory-related diseases. In the present study, the water-soluble polysaccharides (BCPs) were isolated from Bupleurum chinense, and we evaluated their therapeutical effects on acute inflammatory injure and antagonistic function against P-selectin-mediated neutrophil adhesion. Our results showed that BCPs significantly impaired the leukocyte infiltration and relieve lung injury in LPS-induced acute pneumonia model. BCPs significantly blocked the binding of P-selectin to neutrophils and inhibited P-selectin-mediated neutrophils rolling along CHO-P cell monolayer. The result from in vitro protein binding assay showed a direct evidence indicating that BCPs-treatment significantly eliminated the interaction between rhP-Fc and its physiological ligand PSGL-1 at protein level. Together, these results provide a novel therapeutical strategy for amelioration of inflammation-related disease processes by polysaccharides from B. chinense.

Effects of magnoline on P-selectin's expression in diabetic rats and its reno-protection.

BACKGROUND AND OBJECTIVE: Magnoline is an active ingredient of magnolia fargesii with anti-inflammatory and anti-platelet effects. The objective is to explore the renoprotection of magnoline in diabetic rats and its effects on P-selectin. METHODS: Thirty-six rats were randomized into 4 groups-normal control group (C), diabetic group (D), small-dose magnoline treatment group (M1) and large-dose magnoline treatment group (M2) (n=9 in each group). Streptozotocin was selected to construct diabetic rat model, and group M1 and group M2 were treated with magnoline 0.5mg/Kg.d and 2mg/Kg.d respectively. Urinary albumin excretion rate, renal function, levels of P-selectin and TGF-ß1 were observed after 16 weeks. RESULTS: Levels of albuminuria and serum creatinine of group M1 (1078.9 ± 77.3µg/24h, 29.7 ± 3.9µmol/L) and M2 (852.9 ± 80.1µg/24h, 30.9 ± 2.9µmol/L) were lower than group D (1572.8 ± 176.2µg/24h, 39.4 ± 4.1µmol/L) (P <0.05). Serum levels of P-selectin in group M1 and M2 were lower than group D (P <0.05). The renal expression of P-selectin and TGF-ß1 in group M1 and M2 were significantly attenuated respectively. CONCLUSIONS: Magnoline has reno-protective effects on diabetic rats which may be related to the inhibition of P-selectin.

A potent oral P-selectin blocking agent improves microcirculatory blood flow and a marker of endothelial cell injury in patients with sickle cell disease.

Abnormal blood flow accounts for most of the clinical morbidity of sickle cell disease (SCD) [1,2]. Most notably, occlusion of flow in the microvasculature causes the acute pain crises [3] that are the commonest cause for patients with SCD to seek medical attention [4] and major determinants of their quality of life [5]. Based on evidence that endothelial P-selectin is central to the abnormal blood flow in SCD we provide results from four of our studies that are germane to microvascular blood flow in SCD. A proof-of-principle study established that doses of heparin lower than what are used for anticoagulation but sufficient to block P-selectin improved microvascular blood flow inpatients with SCD. An in vitro study showed that Pentosan Polysulfate Sodium (PPS) had greater P-selectin blocking activity than heparin. A Phase I clinical study demonstrated that a single oral dose of PPS increased microvascular blood flow in patients with SCD. A Phase II clinical study that was not completed documented that daily oral doses of PPS administered for 8 weeks lowered plasma levels of sVCAM-1 and tended to improve microvascular blood flow in patients with SCD. These data support the concept that P-selectin on the microvascular endothelium is critical to both acute vascular occlusion and chronically impaired microvascular blood flow in SCD. They also demonstrate that oral PPS is beneficial to microvascular sickle cell blood flow and has potential as an efficacious agent for long-term prophylactic therapy of SCD.

Standardized flavonoid-rich Eugenia jambolana seed extract retards in vitro and in vivo LDL oxidation and expression of VCAM-1 and P-selectin in atherogenic rats.

The present inventory evaluates anti-atherogenic potential of flavonoid-rich Eugenia jambolana seed extract (EJSE) against in vitro low-density lipoprotein (LDL) oxidation, foam cell formation, and atherogenic (ATH) diet-induced experimental atherosclerosis in rats. EJSE was able to prevent in vitro LDL oxidation and oxidized LDL-induced macrophage foam cell formation. Also, EJSE supplementation to ATH rats significantly minimized increment in serum markers of LDL oxidation. The ex vivo oxidation indices were also minimized in LDL of EJSE-treated animals. Microscopic evaluation of thoracic aorta of ATH + EJSE rats recorded minimal evidence of atheromatous plaque formation, accumulation of lipid laden macrophages, calcium deposition, and expression of cell adhesion molecules (vascular cell adhesion molecule-1 and P-selectin). This is the first scientific report that demonstrates anti-atherogenic potential of EJSE and warrants further evaluation at clinical level.

Isolation and characterization of N-feruloyltyramine as the P-selectin expression suppressor from garlic (Allium sativum).

Garlic (Allium sativum) is a medicinal and culinary plant reported to have several positive health effects on cardiovascular diseases, particularly via suppressing platelet activation. Therefore, active compounds inhibiting platelet activation were isolated from garlic extract using a P-selectin expression suppressing activity-guided fractionation technique. Garlic cloves were extracted with methanol, sequentially partitioned using ethyl acetate, and n-butanol. The ethyl acetate portion was fractionated using silica gel chromatography. The fraction with highest P-selectin expression suppressing activity was further purified using HPLC, and the compounds in the fraction were analyzed using MS, MS/MS, and NMR spectroscopic methods. Using NMR spectroscopy, the compound with highest suppressing activity was confirmed as N-feruloyltyramine. At the concentration of 0.05 microM, N-feruloyltyramine was able to suppress P-selectin expression on platelets by 31% (P < 0.016). Since COX enzymes are deeply involved in the regulation of P-selectin expression on platelets, potential effects of N-feruloyltyramine on COX enzymes were investigated. As expected at the concentration of 0.05 microM, N-feruloyltyramine was found to be a very potent compound able to inhibit COX-I and -II enzymes by 43% (P < 0.012) and 33% (P < 0.014), respectively. N-Feruloyltyramine is likely to inhibit COX enzymes, thereby suppressing P-selectin expression on platelets.

P-selectin antagonism reduces thrombus formation in humans.

BACKGROUND: Interaction of P-selectin with its glycoprotein ligand (P-selectin glycoprotein ligand type 1) mediates inflammatory processes that may also include vascular thrombosis. Platelet P-selectin expression is increased in patients with coronary heart disease, and its antagonism represents a potential future therapeutic target for the prevention and treatment of atherothrombosis. AIM: To investigate the effects of the novel small molecule P-selectin antagonist PSI-697 on thrombus formation in humans. METHODS AND RESULTS: In a double-blind randomized crossover study, thrombus formation was measured in 12 healthy volunteers, using the Badimon ex vivo perfusion chamber under conditions of low and high shear stress. Saline placebo, low-dose (2 m) and high-dose (20 m) PSI-697 and the glycoprotein IIb-IIIa receptor antagonist tirofiban (50 ng mL(-1)) were administered into the extracorporeal circuit prior to the perfusion chamber. As compared with saline placebo, blockade of platelet glycoprotein IIb-IIIa receptor with tirofiban produced 28% and 56% reductions in thrombus formation in the low-shear and high-shear chambers, respectively. PSI-697 caused a dose-dependent, but more modest, reduction in thrombus formation. Low-dose PSI-796 (2 m) reduced total thrombus area by 14% (P = 0.04) and 30% (P = 0.0002) in the low-shear and high-shear chambers, respectively. At the high dose (20 m), PSI-697 reduced total thrombus area by 18% (P = 0.0094) and 41% (P = 0.0008) in the low-shear and high-shear chambers, respectively. CONCLUSIONS: P-selectin antagonism with PSI-697 reduces ex vivo thrombus formation in humans. These findings provide further evidence that P-selectin antagonism may be a potential target for the prevention and treatment of cardiovascular disease.

Strategies for generating less toxic P-selectin inhibitors: pharmacophore modeling, virtual screening and counter pharmacophore screening to remove toxic hits.

This paper describes the generation of ligand-based as well as structure-based models and virtual screening of less toxic P-selectin receptor inhibitors. Ligand-based model, 3D-pharmacophore was generated using 27 quinoline salicylic acid compounds and is used to retrieve the actives of P-selectin. This model contains three hydrogen bond acceptors (HBA), two ring aromatics (RA) and one hydrophobic feature (HY). To remove the toxic hits from the screened molecules, a counter pharmacophore model was generated using inhibitors of dihydrooratate dehydrogenase (DHOD), an important enzyme involved in nucleic acid synthesis, whose inhibition leads to toxic effects. Structure-based models were generated by docking and scoring of inhibitors against P-selectin receptor, to remove the false positives committed by pharmacophore screening. The combination of these ligand-based and structure-based virtual screening models were used to screen a commercial database containing 538,000 compounds.