The Prostacyclin Analog, Treprostinil Sodium, Provides Symptom Relief in Severe Buerger’s Disease

Protective effects and potential mechanism of salvianolic acid B on sodium laurate-induced thromboangiitis obliterans in rats

BACKGROUND

The root of Salvia miltiorrhiza f. alba (RSMA) (Lamiaceae) is used for the treatment of patients with thromboangiitis obliterans (TAO) in traditional Chinese medicine. Previously, a mixture of phenolic acids extracted from RSMA has shown significant protective effects on TAO rats.

PURPOSE

This study investigates the inhibitory effects of salvianolic acid B on TAO induced by sodium laurate injection in rats to explore the effective constituents of RSMA in TAO treatment.

METHODS

TAO rats were developed using injected sodium laurate. After treatment with ligustrazine hydrochloride (15 mg/kg) and various doses of salvianolic acid B (10, 20, 40 mg/kg) by tail intravenous injection, levels of thromboxane B₂ (TXB₂), 6-keto-prostaglandin F_1α (6-keto-PGF_1α) and endothelin-1 (ET-1) in plasma were determined using enzyme-linked immunosorbent assay. The right femoral arteries were studied by hematoxylin and eosin staining and immunohistochemical analysis to determine pathological changes and overexpression of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) in the femoral artery walls of TAO rats.

RESULTS

Salvianolic acid B significantly decreased the expressions of TXB₂ and ET-1 and increased the expression of 6-keto-PGF_1α in plasma, and significantly inhibited the overexpression of TNF-α and iNOS in the femoral artery walls of TAO rats at medium and high doses.

CONCLUSION

Salvianolic acid B has a protective effect on TAO rats. The mechanism may involve inhibition of thrombosis and TAO-associated inflammatory responses, which may explain the success of RSMA treatment of TAO in humans in traditional Chinese medical practice. Hence, it may be a potential drug for TAO treatment in conventional medicine.

Thromboangiitis obliterans (Buerger's disease)

Thromboangiitis Obliterans is a non-atherosclerotic inflammatory disease of unknown etiology, which has a strong association with tobacco. We present current concepts on the pathophysiology and diagnosis, as well as a review in treatments.

•

Current concepts on the pathophysiology and diagnosis of Thromboangiitis Obliterans.

•

Importance of complete abstinence of tobacco.

•

Actual Treatments of Thromboangiitis Obliterans.

Open label study of escalating doses of oral treprostinil diethanolamine in patients with systemic sclerosis and digital ischemia: pharmacokinetics and correlation with digital perfusion

Introduction

Treprostinil diethanolamine is an innovative salt form of the prostacyclin analogue, treprostinil sodium, developed as an oral sustained release (SR) osmotic tablet. The availability of a formulation permitting convenient systemic delivery might have applicability to scleroderma vascular complications. We evaluated pharmacokinetics and perfusion in scleroderma patients with digital ischemia following escalating twice-daily doses of treprostinil diethanolamine SR.

Methods

Scleroderma patients with digital ulcers were enrolled in this dual-center, open-label, phase I pharmacokinetic study. Drug concentrations and perfusion, quantified by laser Doppler imaging, were measured over 12 hours at the 2 mg and 4 mg (or maximally tolerated) doses. Pharmacokinetic parameters were determined from individual plasma concentration versus time profiles using non-compartmental analysis methods. Digital perfusion and skin temperature were modeled as a function of log-transformed drug concentration and other covariates by performing repeated measures analyses using random effects models.

Results

Nineteen scleroderma patients (84% female, 53% limited scleroderma) received treprostinil diethanolamine SR with dose titration up to 4 mg twice daily as tolerated. Peak concentrations (mean maximum plasma concentration (C_max) = 1,176 and 2,107 pg/mL) occurred approximately 3.6 hours after dose administration, and overall exposure (under the plasma concentration-time curve from time 0 to 12 hours post dose (AUC_0-12) = 7,187 and 12,992 hr*pg/mL) was linear between the 2 mg and 4 mg doses. Perfusion and digital skin temperature were positively associated with log-transformed plasma concentration at the 4 mg dose (P = 0.015 and P = 0.013, respectively). The most frequent adverse events were similar to those seen with prostacyclin analogues.

Conclusions

Oral treprostinil diethanolamine was effectively absorbed in patients with scleroderma. Drug administration was temporally associated with improved cutaneous perfusion and temperature. Treprostinil diethanolamine may provide a new therapeutic option for Raynaud's phenomenon and the peripheral vascular disease of scleroderma.

Trial Registration

ClinicalTrials.gov NCT00848939.

Electronic supplementary material

The online version of this article (doi:10.1186/ar4216) contains supplementary material, which is available to authorized users.

Binding and activity of the prostacyclin receptor (IP) agonists, treprostinil and iloprost, at human prostanoid receptors: treprostinil is a potent DP1 and EP2 agonist

The prostacyclin analogues, iloprost and treprostinil are extensively used in treating pulmonary hypertension. Their binding profile and corresponding biochemical cellular responses on human prostanoid receptors expressed in cell lines, have now been compared. Iloprost had high binding affinity for EP1 and IP receptors (Ki 1.1 and 3.9 nM, respectively), low affinity for FP, EP3 or EP4 receptors, and very low affinity for EP2, DP1 or TP receptors. By contrast, treprostinil had high affinity for the DP1, EP2 and IP receptors (Ki 4.4, 3.6 and 32 nM, respectively), low affinity for EP1 and EP4 receptors and even lower affinity for EP3, FP and TP receptors. In functional assays, iloprost had similar high activity in elevating cyclic AMP levels in cells expressing the human IP receptor and stimulating calcium influx in cells expressing EP1 receptors (EC50 0.37 and 0.3 nM, respectively) with the rank order of activity on the other receptors comparable to the binding assays. As with binding studies, treprostinil elevated cyclic AMP with a similar high potency in cells expressing DP1, IP and EP2 receptors (EC50 0.6, 1.9 and 6.2 nM, respectively), but had low activity at the other receptors. Activation of IP, DP1 and EP2 receptors, as with treprostinil, can all result in vasodilatation of human pulmonary arteries. However, activation of EP1 receptors can provoke vasoconstriction, and hence may offset the IP-receptor mediated vasodilator effects of iloprost. Treprostinil may therefore differ from iloprost in its overall beneficial pulmonary vasorelaxant profile and other pharmacological actions, especially in diseases where the IP receptor is down-regulated.