heparitin-sulfate and Hypertension--Pulmonary

Here, we sought to elucidate the role of CAR (a cyclic peptide) in the accumulation and distribution of fasudil, a drug for pulmonary arterial hypertension (PAH), in rat lungs and in producing pulmonary specific vasodilation in PAH rats. As such, we prepared liposomes of fasudil and CAR-conjugated liposomal fasudil and assessed the liposomes for CAR conjugation, physical properties, entrapment efficiencies, in vitro release profiles, and stabilities upon incubation in cell culture media, storage, and aerosolization. We also studied the cellular uptake of fasudil in different formulations, quantified heparan sulfate (HS) in pulmonary arterial smooth muscle cells (PASMCs), and investigated the distribution of the liposomes in the lungs of PAH rats. We assessed the drug accumulation in a close and recirculating isolated perfused rat lung model and studied the pharmacokinetics and pharmacological efficacy of the drug and formulations in Sugen/hypoxia-induced PAH rats. The entrapment efficiency of the liposomal fasudil was 95.5 ± 4.5%, and the cumulative release was 93.95 ± 6.22%. The uptake of CAR liposomes by pulmonary arterial cells and their distribution and accumulation in the lungs were much greater than those of no-CAR-liposomes. CAR-induced increase in the cellular uptake was associated with an increase in HS expression by rat PAH-PASMCs. CAR, when conjugated with liposomal fasudil and given via an intratracheal instillation, extended the elimination half-life of the drug by four-fold compared with fasudil-in-no-CAR-liposomes given via the same route. CAR-conjugated liposomal fasudil, as opposed to fasudil-in-no-CAR-liposomes and CAR pretreatment followed by fasudil-in-no-CAR-liposomes, reduced the mean pulmonary arterial pressure by 40-50% for 6 h, without affecting the mean systemic arterial pressure. On the whole, this study suggests that CAR aids in concentrating the drug in the lungs, increasing the cellular uptake, extending the half-life of fasudil, and eliciting a pulmonary-specific vasodilation when the peptide remains conjugated on the liposomal surface, but not when CAR is given as a pretreatment or alone as an admixture with the drug.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Disease Models, Animal; Half-Life; Heparitin Sulfate; Humans; Hypertension, Pulmonary; Liposomes; Lung; Male; Myocytes, Smooth Muscle; Peptides, Cyclic; Pulmonary Artery; Rats; Time Factors; Vasodilation; Vasodilator Agents

Pulmonary arterial hypertension (PAH) is a rare disease characterized by increased pulmonary pressure and vascular remodelling as a consequence of smooth muscle cell proliferation, endothelial cell dysfunction and inflammatory infiltrates. Meprin α is a metalloproteinase whose substrates include adhesion and cell-cell contact molecules involved in the process of immune cell extravasation. In this study, we aimed to unravel the role of meprin α in PAH-induced vascular remodelling. Our results showed that meprin α was present in the apical membrane of endothelial cells in the lungs and pulmonary arteries of donors and idiopathic PAH (IPAH) patients. Elevated circulating meprin α levels were detected in the plasma of IPAH patients. In vitro binding assays and electron microscopy confirmed binding of meprin α to the glycocalyx of human pulmonary artery endothelial cells (hPAECs). Enzymatic and genetic approaches identified heparan sulphate (HS) as an important determinant of the meprin α binding capacity to hPAEC. Meprin α treatment protected from excessive neutrophil infiltration and the protective effect observed in the presence of neutrophils was partially reversed by removal of HS from hPAEC. Importantly, HS levels in pulmonary arteries were decreased in IPAH patients and binding of meprin α to HS was impaired in IPAH hPAEC. In summary, our results suggest a role of HS in docking meprin α to the endothelium and thus in the modulation of inflammatory cell extravasation. In IPAH, the decreased endothelial HS results in the reduction of meprin α binding which might contribute to enhanced inflammatory cell extravasation and potentially to pathological vascular remodelling.

Topics: Animals; Cells, Cultured; Endothelium, Vascular; Heparitin Sulfate; Humans; Hypertension, Pulmonary; Immune System Diseases; Inflammation; Leukocyte Disorders; Lung; Male; Metalloendopeptidases; Mice; Mice, Inbred C57BL; Mice, Knockout; Protein Binding; Pulmonary Artery; Vascular Remodeling

Patients with heparin-induced thrombocytopenia urgently requiring surgery with cardiopulmonary bypass (CPB) present a unique management challenge that must be addressed by the use of alternative anticoagulants. Although clinical success with the direct thrombin inhibitor hirudin has been reported, there is sparse information in the literature supporting the efficacy of this drug as an anti-thrombotic to prevent fibrin formation during CPB. In this report, we describe the efficacy of this drug to prevent thrombin-mediated fibrin formation during CPB.

Topics: Adult; Anticoagulants; Cardiopulmonary Bypass; Chondroitin Sulfates; Contraindications; Dermatan Sulfate; Endarterectomy; Fibrinolytic Agents; Fibrinopeptide A; Heparin; Heparitin Sulfate; Hirudins; Humans; Hypertension, Pulmonary; Hypothermia, Induced; Male; Peptide Fragments; Postoperative Complications; Prothrombin; Pulmonary Embolism; Purpura, Thrombocytopenic, Idiopathic; Recombinant Proteins; Thrombectomy; Thrombin; Thrombosis

Patients with heparin-induced thrombocytopenia requiring urgent cardiac surgery present a unique challenge that must be addressed by the use of nonheparin alternatives for anticoagulation during cardiopulmonary bypass. Although isolated cases have been presented involving the use of antithrombin III independent thrombin inhibitor hirudin in this situation, its ability to completely inhibit thrombin activity has not been demonstrated. In this report we describe the efficacy of this drug in inhibiting thrombin during a case requiring prolonged cardiopulmonary bypass.

Topics: Aged; Anticoagulants; Blood Coagulation; Cardiopulmonary Bypass; Chondroitin Sulfates; Contraindications; Dermatan Sulfate; Endarterectomy; Female; Heparin; Heparitin Sulfate; Hirudins; Humans; Hypertension, Pulmonary; Plasma; Platelet Transfusion; Pulmonary Embolism; Recombinant Proteins; Thrombectomy; Thrombin; Thrombocytopenia; Time Factors; Warfarin