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

Systemic Sclerosis-Associated Pulmonary Arterial Hypertension: From Bedside to Bench and Back Again

Systemic sclerosis (SSc) is a heterogeneous disease characterized by autoimmunity, vasculopathy, and fibrosis which affects the skin and internal organs. One key aspect of SSc vasculopathy is pulmonary arterial hypertension (SSc-PAH) which represents a leading cause of morbidity and mortality in patients with SSc. The pathogenesis of pulmonary hypertension is complex, with multiple vascular cell types, inflammation, and intracellular signaling pathways contributing to vascular pathology and remodeling. In this review, we focus on shared molecular features of pulmonary hypertension and those which make SSc-PAH a unique entity. We highlight advances in the understanding of the clinical and translational science pertinent to this disease. We first review clinical presentations and phenotypes, pathology, and novel biomarkers, and then highlight relevant animal models, key cellular and molecular pathways in pathogenesis, and explore emerging treatment strategies in SSc-PAH.

Efficacy of adjunctive ambrisentan treatment for digital ulcers in patients with systemic sclerosis: a case series study

Purpose: The efficacy of adjunctive ambrisentan treatment in patients with systemic sclerosis (SSc) suffering from digital ulcers (DUs) was investigated.Material and methods: Patients (4 males, 7 females) diagnosed with SSc at our hospital between 2017 and 2022 were enrolled. Ten of them had diffuse SSc, while one had limited SSc. These patients received daily 5 mg doses of ambrisentan in addition to their regular SSc treatment for 16 weeks. Parameters including the total number and size of existing and new DUs, Visual Analog Score (VAS), frequency of Raynaud's phenomenon (RP) attacks, and any adverse effects were assessed.Results: At baseline, the median number and size of DUs was 3.0 (interquartile range (IQR): 2.0-4.0 cm) and 0.4 cm (IQR: 0.3-0.5 cm), respectively. Following the intervention, seven patients with a median of 2.0 DUs and a size of 0.35 cm (IQR: 0.15-0.45 cm) at baseline achieved complete healing. Significant improvements were also observed in other patients. VAS scores decreased from a baseline median of 5.0-0.0 (IQR: 0.0-1.0), and both the frequency and duration of RP attacks notably reduced.Conclusion: Adjunctive ambrisentan therapy proved effective in promoting DU healing and preventing new DUs in SSc patients.

New and Delayed Artifactual Hypoglycemia Following Septic Shock in Two Scleroderma Patients

The term artifactual hypoglycemia refers to a discrepancy between plasma glucose levels and what is noted on fingerstick glucose checks. In this report, we discuss the cases of two patients with scleroderma and Raynaud's phenomenon who developed artifactual hypoglycemia while recovering from critical illness. In both cases, validation by earlobe measurements helped avoid further escalation of care and potential patient safety issues. There have been previous reports of artifactual hypoglycemia in this patient population, but the unique timing of symptom onset in these two patients provides a more nuanced understanding of the pathophysiology of this phenomenon.

Autoantibodies as Biomarker and Therapeutic Target in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare connective tissue disorder characterized by immune dysregulation evoking the pathophysiological triad of inflammation, fibrosis and vasculopathy. In SSc, several alterations in the B-cell compartment have been described, leading to polyclonal B-cell hyperreactivity, hypergammaglobulinemia and autoantibody production. Autoreactive B cells and autoantibodies promote and maintain pathologic mechanisms. In addition, autoantibodies in SSc are important biomarkers for predicting clinical phenotype and disease progression. Autoreactive B cells and autoantibodies represent potentially promising targets for therapeutic approaches including B-cell-targeting therapies, as well as strategies for unselective and selective removal of autoantibodies. In this review, we present mechanisms of the innate immune system leading to the generation of autoantibodies, alterations of the B-cell compartment in SSc, autoantibodies as biomarkers and autoantibody-mediated pathologies in SSc as well as potential therapeutic approaches to target these.

Endothelin Receptor Antagonists: Status Quo and Future Perspectives for Targeted Therapy

The endothelin axis, recognized for its vasoconstrictive action, plays a central role in the pathology of pulmonary arterial hypertension (PAH). Treatment with approved endothelin receptor antagonists (ERAs), such as bosentan, ambrisentan, or macitentan, slow down PAH progression and relieves symptoms. Several findings have indicated that endothelin is further involved in the pathogenesis of certain other diseases, making ERAs potentially beneficial in the treatment of various conditions. In addition to PAH, this review summarizes the use and perspectives of ERAs in cancer, renal disease, fibrotic disorders, systemic scleroderma, vasospasm, and pain management. Bosentan has proven to be effective in systemic sclerosis PAH and in decreasing the development of vasospasm-related digital ulcers. The selective ERA clazosentan has been shown to be effective in preventing cerebral vasospasm and delaying ischemic neurological deficits and new infarcts. Furthermore, in the SONAR (Study Of Diabetic Nephropathy With Atrasentan) trial, the selective ERA atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease. These data suggest atrasentan as a new therapy in the treatment of diabetic nephropathy and possibly other renal diseases. Preclinical studies regarding heart failure, cancer, and fibrotic diseases have demonstrated promising effects, but clinical trials have not yet produced measurable results. Nevertheless, the potential benefits of ERAs may not be fully realized.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Digital ulcers in scleroderma patients: A retrospective observational study

BACKGROUND

The guidelines for digital ulcers (DUs) management in systemic sclerosis (SSc) indicate the use of iloprost to induce wound healing and bosentan to prevent the onset of new DU. The aim of our study was to evaluate whether the combination treatment may surmount the effect of the single drug.

METHODS

We analyzed data regarding 34 patients with SSc and at least one active DU persisting despite 6 months of iloprost therapy, and treated for other 6 months with a combination therapy, i.e. iloprost plus bosentan.

RESULTS

Overall, patients initially presented 69 DUs (58 on the fingers and 11 on the legs). At the end of the study 34 (49.3%) DUs were completely healed (responding, R), 18 (26.1%) started the healing process (partially responding, PR), and 17 (24.6%) did not respond (NR) to therapy. No new DU was recorded and the ulcers localized on the legs did not respond to the combination therapy. Finally, data have been analyzed by dividing the patients in two groups according to the fibrosis level on the finger. In the group with mild fibrosis, 83.4% of DUs resulted with showing complete healing while, in the group with severe fibrosis, only 18% of DUs were healed (P = 0.024).

CONCLUSION

The treatment with iloprost plus bosentan is effective in determining healing of DUs in SSc patients with mild digital skin fibrosis. Conversely, the severity of skin fibrosis strongly influences the healing process of DUs. The study confirmed the efficacy of bosentan to prevent onset of new DUs.

The association between vibration and vascular injury in rheumatic diseases: a review of the literature

Vascular manifestations can be seen early in the pathogenesis of inflammatory rheumatic diseases. Animal experiments, laboratory and clinical findings indicated that acute or long-term vibration exposure can induce vascular abnormalities. Recent years, in addition to Raynaud's phenomenon (RP), vibration as a risk factor for other rheumatic diseases has also received corresponding considered. This review is concentrated upon the role of vibration in the disease of systemic sclerosis (SSc). In this review, we are going to discuss the main mechanisms which are thought to be important in pathophysiology of vascular injury under the three broad headings of "vascular", "neural" and "intravascular". Aspects on the vibration and vascular inflammation are briefly discussed. And the epidemiological studies related to vibration studies in SSc and other rheumatic diseases are taken into account.

Management of Raynaud's phenomenon and digital ischemia

This review focuses on new findings and developments relevant to the clinician caring for patients with primary and secondary [especially systemic sclerosis (SSc)-related] Raynaud phenomenon (RP). In the last 18 months, several clinical trials and observational studies of RP and of SSc-related digital ulceration have been published, reflecting increased awareness of disease burden and increased interest by pharmaceutical companies: new insights into pathophysiology are driving new approaches to treatment. Key developments are the increased use of phosphodiesterase type V inhibitors in severe RP, and of bosentan (an endothelin-1 receptor antagonist) for prevention of recurrent SSc-related digital ulcers. Other treatments being researched include topical glyceryl trinitrate (applied locally to the digits), botulinum toxin (for severe digital ischemia/ulceration), and several other drugs including oral prostanoids. Increased availability and interest in nailfold capillaroscopy, by facilitating early diagnosis of SSc, should pave the way for studies of early intervention and vascular protection.