Successful treatment of systemic-sclerosis-related digital ulcers with a selective endothelin type A receptor antagonist (sitaxentan)

Endothelin receptor antagonists in sickle cell disease: A promising new therapeutic approach

Sickle cell disease (SCD) is a genetic hematologic disorder that is characterized by a variety of potentially life threatening acute and chronic complications. Currently, hydroxyurea is the only clinically approved pharmacological therapy for the treatment of SCD, and the continued prevalence of severe disease complications underscores the desperate need for the development of new therapeutic agents. Central features of the sickle cell disease milieu, including hypoxia, oxidative stress, and thrombosis, are established enhancers of endothelin-1 (ET-1) synthesis. This conceptual connection between ET-1 and SCD was confirmed by multiple studies that demonstrated markedly elevated plasma and urinary levels of ET-1 in SCD patients. Direct evidence for the involvement of ET-1 signaling in the development of SCD pathologies has come from studies using endothelin receptor antagonists in SCD mice. This review summarizes recent studies that have implicated ET-1 signaling as a mechanistic contributor to renal, vascular, pulmonary, and nociceptive complications of sickle cell disease and discusses the potential for the use of ET receptor antagonists in the treatment of SCD.

Endothelin Receptor Antagonists for the Treatment of Raynaud's Phenomenon and Digital Ulcers in Systemic Sclerosis

Systemic sclerosis is a connective tissue disease characterized by fibrosis of the skin, internal organs, and widespread vasculopathy. Raynaud's phenomenon and digital ulcers are vascular manifestations of this disease and cause significant morbidity. Current treatments are only moderately effective in reducing the severity of Raynaud's in a portion of patients and typically do not lead to substantial benefit in terms of the healing or prevention of digital ulcers. Several studies have evaluated the efficacy of targeting the vasoconstrictor endothelin-1 for the treatment of systemic sclerosis-associated vascular disease. The purpose of this paper is to summarize the published studies and case reports evaluating the efficacy of endothelin receptor antagonists in the treatment of Raynaud's phenomenon and digital ulcers associated with systemic sclerosis.

Vascular involvement in systemic sclerosis (scleroderma)

Systemic sclerosis (SSc) is an acquired multiorgan connective tissue disease with variable mortality and morbidity dictated by clinical subset type. The etiology of the basic disease and pathogenesis of the systemic autoimmunity, fibrosis, and fibroproliferative vasculopathy are unknown and debated. In this review, the spectrum of vascular abnormalities and the options currently available to treat the vascular manifestations of SSc are discussed. Also discussed is how the hallmark pathologies (ie, how autoimmunity, vasculopathy, and fibrosis of the disease) might be effected and interconnected with modulatory input from lysophospholipids, sphingosine 1-phosphate, and lysophosphatidic acid.

Two faces of the same coin: Raynaud phenomenon and digital ulcers in systemic sclerosis

Systemic sclerosis (SSc) is characterized by wide-spread fibrosis, activation of immune system with production of autoantibodies and extensive vascular damage. Raynaud's phenomenon (RP) and digital ulcers (DU) represent two faces of the same coin in SSc vasculopathy. RP, the earliest manifestation of the vascular involvement, is due to an excessive vasospasm of digital arteries, precapillary arterioles and cutaneous arteriovenous shunts, usually in response to cold exposure or other stimuli. DU are a severe complication of microvessel involvement and also of the persistent vasospasm of RP. Thus, the management of RP and DU requires a multimodal approach using a combination of pharmacological, non-pharmacological, and surgical treatments. Currently, the treatment of these complications represents a great challenge for all physicians.

Digital ischemia in scleroderma spectrum of diseases

Systemic Sclerosis (Scleroderma, SSc) is a disease of unknown etiology characterized by widespread vasculopathy and extracellular matrix deposition leading to fibrosis and autoimmune processes. Digital ischemia (digital ulcers (DUs)) is the hallmark of SSc-related vasculopathy and is characterized by endothelial dysfunction leading to intimal proliferation and thrombosis. It happens frequently (30% of the patients each year) and it is associated with significant morbidity. This paper summarizes the current information regarding pathogenesis, definitions, management, and exploratory therapies in DUs associated with SSc.

Assessing microvascular changes in systemic sclerosis diagnosis and management

Microvascular damage and dysfunction represent the earliest morphological and functional markers of systemic sclerosis (SSc), a progressive connective tissue disease characterized by vascular abnormalities and diffuse fibrosis in the skin and internal organs. These early microvascular changes are clinically mirrored by Raynaud phenomenon, which can be primary (idiopathic) or secondary to several different conditions including SSc. Morphological and functional assessment of the cutaneous microvasculature have crucial implications for diagnosis, prognosis and therapy in SSc and secondary Raynaud phenomenon. Most importantly, imaging with nailfold videocapillaroscopy (NVC) enables the early differentiation between primary and secondary Raynaud phenomenon by identifying morphological patterns specific to various stages of SSc ('early', 'active' and 'late' patterns); the inclusion of these NVC patterns could increase the sensitivity of classification criteria for SSc. Findings on NVC are also markers of SSc severity and progression, as reduced capillary density has been associated with a high risk of developing digital skin ulcers and pulmonary arterial hypertension. Laser Doppler imaging and thermal imaging demonstrate the dysfunctional cutaneous blood flow in response to cold stimuli. Therapies targeting underlying vascular disease in SSc have been successfully designed to improve the symptoms of Raynaud phenomenon and to reduce ischemic injury to involved organs, and NVC patterns have been found to improve following targeted therapy; however, treatment of later fibrosis remains a challenge.