Endothelin and collagen vascular disease: a review with special reference to Raynaud's phenomenon and systemic sclerosis

The historical evolution of knowledge of the involvement of neurohormonal systems in the pathophysiology and treatment of heart failure

Our knowledge of the pathophysiology of heart failure (HF) underwent profound changes during the 1980s. Once thought to be of exclusively structural origin, HF began to be seen as the consequence of hormonal imbalance. A number of seminal studies were published in that decade focusing on the impact of neurohormonal activation in HF. Presently, eight neurohormonal systems are known to have a key role in HF development: four stimulate vasoconstriction and sodium/water retention (the sympathetic nervous system, the renin-angiotensin-aldosterone system [RAAS], endothelin, and the vasopressin-arginine system), while the other four stimulate vasodilation and natriuresis (the prostaglandin system, nitric oxide, the dopaminergic system, and the natriuretic peptide system [NPS]). These systems are strongly interconnected and are subject to intricate regulation, functioning together in a delicate homeostasis. Disruption of this homeostasis is characteristic of HF. This review explores the historical development of knowledge on the impact of the neurohormonal systems on HF pathophysiology, from the first studies to current understanding. In addition, the therapeutic potential of each of these systems is discussed, and currently used neurohormonal antagonists are characterized. Special emphasis is given to the latest drug approved for use in HF with reduced ejection fraction, sacubitril/valsartan. This drug combines two different molecules, acting on two different systems (RAAS and NPS) simultaneously.

Microangiopathy in Naifold Videocapillaroscopy and Its Relations to sE- Selectin, Endothelin-1, and hsCRP as Putative Endothelium Dysfunction Markers among Adolescents with Raynaud's Phenomenon

The aim of this study was to analyze the relationship between the qualitative abnormalities on nailfold videocapillaroscopy (NVC), and the concentrations of selected biomarkers (sE-selectin, endothelin-1, high-sensitivity c-reactive protein (hsCRP)) and lipid metabolism parameters in children and adolescents with Raynaud’s phenomenon (RP). Raynaud’s phenomenon, to assess whether nailfold capillary changes may reflect the degree of systemic blood vessel abnormalities. The study group included 66 patients (34 undifferentiated—uRP and 32 secondary—sRP) aged 6–19 years and the control group. In both groups, NVC was performed and the selected biomarkers were measured (sE-selectin, endothelin-1, hsCRP) and lipid profile. Endothelin-1, sE-selectin and hsCRP concentrations in patients from both RP groups were significantly higher; concentration of HDL fraction was significantly lower compared with the control group. The analysis of multiple linear regression demonstrated that megacapillaries most strongly determine the sE-selectin value (p = 0.04) and hsCRP (p = 0.03). Both the total cholesterol and low-density lipoprotein (LDL) fraction concentrations were determined by the presence of avascular areas (p = 0.02). In conclusion, specific pathologic NVC changes were associated with higher endothelial damage biomarkers concentration and adverse changes in the lipid profile.

Nailfold capillaroscopy assessment of microcirculation abnormalities and endothelial dysfunction in children with primary or secondary Raynaud syndrome

Raynaud syndrome (RS) manifests as episodes of transient spasms of peripheral blood vessels, most often in response to cold. The reason of that symptom (primary RS (pRS)) usually cannot be found but may be accompanied by some autoimmune diseases (secondary RS (sRS)). In this study, we assessed microcapillary status and serum concentrations of chosen cytokines, adhesive molecules, and nitric oxide (NO) in patients with pRS and sRS in comparison with healthy children. Eighty-six patients with RS were enrolled into the study, including 52 with pRS and 34 with sRS. The control group consisted of 29 healthy children. A decrease in myorelaxative and anticoagulant abilities was observed, with simultaneous prevalence of vasopressor substances and procoagulative activity. Therefore, several important factors such as endothelin-1 (ET-1), E-selectin (E-sel), interleukin-18 (IL-18), and nitrogen oxide (NO) were also analyzed. Two types of capillaroscopy status were determined: normal and microangiopathic. There was a significant relationship between presence of microangiopathy and higher serum ET-1 (p = 0.018) and E-sel (p = 0.021) levels. Similarly, we have found a correlation between presence of ANA and higher ET-1 (p = 0.005), but not E-sel (p = 0.241). In patients with pRS, we found significant relationship between ANA and higher ET-1 (p = 0.008). No such relations were observed in sRS patients. Our data indicates that external factor-induced vasoconstrictive effects dominated in pRS, whereas in sRS in the course of connective tissue diseases, it was accompanied by coexistent vasodilation due to endothelial dysfunction. The latter phenomenon is at least partially dependent on insufficient NO release.

Lower Doses of Bosentan in Combination With Sildenafil Might be Beneficial in Pulmonary Arterial Hypertension

BACKGROUND

Endothelin-receptor-antagonist, bosentan, has been found to improve the functional capacity and cardiopulmonary hemodynamics in Pulmonary Arterial Hypertension (PAH). Clinical trials have shown the preferable dosage of 125 mg, twice daily, regarding both efficacy and safety.

OBJECTIVES

The purpose of this study was to investigate the effects of lower doses of bosentan (62.5 mg, twice daily) in combination with sildenafil on exercise capacity and clinical events, in 41 patients with idiopathic pulmonary hypertension or chronic thromboembolic pulmonary hypertension (CTEPH).

PATIENTS AND METHODS

We assigned 41 patients with PAH (non-reactive idiopathic or non-operable chronic thromboembolic) to receive 62.5 mg of bosentan twice daily as combination therapy and evaluated the New York heart association (NYHA) functional class, 6-minutes-walk-distance (6MWD), time to clinical worsening, echocardiographic indexes and clinical events, for an average of 18.5 ± 9.5 months.

RESULTS

No adverse drug reaction was observed during the follow-up. Clinical worsening occurred in six (14%) patients, at least one year after treatment, two of the cases failed to respond to 125 mg, twice daily and died. Eight (19%) remained in FC I_II, but didn't reach the goal of 380 meters for 6MWD. All other patients reached the treatment goals according to the latest European society of cardiology (ESC) guidelines.

CONCLUSIONS

We observed acceptable results regarding both efficacy and safety with 62.5 mg of bosentan, twice daily in this group of patients. Further clinical trials investigating PAH with lower dosages of bosentan may be warranted.

Black currant anthocyanins normalized abnormal levels of serum concentrations of endothelin-1 in patients with glaucoma

PURPOSE

Our recent study, which involved a randomized, placebo-controlled, double-masked 24-month trial (Ophthalmologica 2012;228:26-35), revealed that oral administration of black currant anthocyanins (BCACs) slowed down the visual field deterioration and elevation of ocular blood flow of open-angle glaucoma (OAG). To elucidate the underlying mechanisms of these BCAC-induced effects, as possible factors affecting glaucomatous optic neuropathy, changes of serum endothelin-1 (ET-1), nitric oxide (NO), and antioxidative activities were examined in the present study.

METHODS

From among patients with OAG who participated in the randomized, placebo-controlled, double-masked trial, serum specimens were obtained from BCAC-treated (n=19) or placebo-treated (n=19) patients at baseline and every 6 months. Healthy volunteers (n=20) with age and gender matching the patients were used as a control. Serum ET-1 concentration, [NO2(-)] and [NO2(-) + NO3(-)] levels, advanced oxidation protein products (AOPP), and antioxidant activities were measured by using commercially available kits.

RESULTS

At the trial baseline, serum ET-1 concentrations were significantly lower in patients with OAG (BCACs, 3.18±1.06 pg/mL; placebo, 3.44±0.84 pg/mL) than those in healthy volunteers (4.38±1.03 pg/mL) (one-way analysis of variance and a Tukey's multiple comparison post hoc test, P<0.05). Upon administration of BCACs, serum ET-1 concentrations increased to the levels of those in healthy volunteers during the 24-month period. In contrast, those of placebo-treated patients remained at lower levels (3.82±1.14 pg/mL). While [NO2(-)] and [NO2(-)+NO3(-)] levels, AOPP, and antioxidative activities of patients from both the BCACs and placebo groups showed comparable levels to those of healthy subjects at baseline, no significant changes were observed during the observational period in either the BCAC or placebo groups.

CONCLUSIONS

Among the possible beneficial effects of BCACs toward visual field progression in patients with OAG, our present results suggest that BCACs caused normalization of serum ET-1 levels, and this may modulate ET-1-dependent regulation of the ocular blood hemodynamics.

Bosentan Improves Skin Perfusion of Hands in Patients with Systemic Sclerosis with Pulmonary Arterial Hypertension

Objective.

Our aim was to investigate effects of bosentan on hand perfusion in patients with systemic sclerosis (SSc) with pulmonary arterial hypertension (PAH), using laser Doppler perfusion imaging (LDPI).

Methods.

We enrolled 30 SSc patients with PAH, 30 SSc patients without PAH, and 30 healthy controls. In SSc patients and healthy controls at baseline, skin blood flow of the dorsum of the hands was determined with a Lisca laser Doppler perfusion imager. The dorsal surface of the hands was divided into 3 regions of interest (ROI). ROI 1 included 3 fingers of the hand from the second to the fourth distally to the proximal interphalangeal finger joint. ROI 2 included the area between the proximal interphalangeal and the metacarpophalangeal joint. ROI 3 included only the dorsal surface of the hand without the fingers. LDPI was repeated in SSc patients and controls after 4, 8, and 16 weeks of treatment. In SSc patients, nailfold videocapillaroscopy and Raynaud Condition Score (RCS) were performed at baseline and at 4, 8, and 16 weeks.

Results.

SSc patients with PAH enrolled in the study received treatment with bosentan as standard care for PAH. In these patients with PAH, after 8 and 16 weeks of treatment, bosentan improved minimum, mean, and maximum perfusion and the perfusion proximal-distal gradient. Bosentan seems to be most effective in patients with the early and active capillaroscopic pattern than in patients with the late pattern. Bosentan improved skin blood flow principally in the ROI 1 compared to the ROI 2 and ROI 3. Bosentan restored the perfusion proximal-distal gradient in 57% of SSc patients with the early capillaroscopic pattern. No significant differences from baseline were observed in the RCS in SSc patients with PAH.

Conclusion.

Bosentan improved skin perfusion in SSc patients with PAH, although it did not ameliorate symptoms of Raynaud’s phenomenon. Skin blood perfusion increased in SSc patients with PAH, particularly in the skin region distal to the proximal interphalangeal joint, and in patients with the early/active capillaroscopic pattern. Double-blind randomized clinical trials are needed to evaluate the effects of bosentan on skin perfusion of SSc patients without PAH and with active digital ulcers.

Laser Doppler Perfusion Imaging Is Useful in the Study of Raynaud’s Phenomenon and Improves the Capillaroscopic Diagnosis

Objective.

To investigate capillary morphology and skin blood flow of dorsal hands by nailfold videocapillaroscopy (NVC) and laser Doppler perfusion imaging (LDPI), respectively, in patients with primary Raynaud’s phenomenon (PRP) and systemic sclerosis (SSc) and to compare the results with those obtained in healthy controls.

Methods.

The study group consisted of 142 patients with SSc, 88 patients with PRP, and 147 healthy controls. NVC was performed in all the groups examined. In patients with SSc the capillaroscopic pattern was classified as early, active, or late group pattern. A baseline skin blood flow determination of the dorsum of the subject’s hands was acquired through a low-energy 670 nm Lisca Laser Doppler Perfusion Imager.

Results.

In the healthy controls the perfusion distribution pattern was homogeneous, with a proximal-distal perfusion gradient. In patients with PRP, the perfusion distribution pattern was homogeneous, but the proximal-distal perfusion gradient was absent. Finally, in patients with SSc the perfusion distribution pattern was dyshomogeneous and a proximal-distal gradient was absent. The minimum perfusion, mean perfusion, maximum perfusion, and standard deviation, calculated as variation by means of each measurement site, were significantly different in all the groups examinated.

Conclusion.

NVC represents the best method to analyze microvascular damage in rheumatic diseases. LDPI improves the evaluation of vascular damage in patients with SSc. The LDPI and the capillaroscopic images fully matched the definition of the various stages of vascular digital damage in SSc.

Effect of Bosentan on Plasma Markers of Endothelial Cell Activity in Patients with Secondary Pulmonary Hypertension Related to Connective Tissue Diseases

Objective.

To evaluate plasma markers of endothelial cell activity in patients with pulmonary arterial hypertension (PAH) induced by connective tissue diseases (CTD) before and after 3-month administration of bosentan.

Methods.

We quantified E, L and P-selectin (sE-S, sL-S, sP-S), thrombomodulin (TM), monocyte-chemotactic protein 1 (MCP-1), human soluble CD40 ligand (sCD40L), and nitric oxide (NO) in 18 patients and 18 controls. We evaluated right ventricular systolic pressure (RVSP) and the 6-minute walk test (6-MWT).

Results.

All plasma markers but sL-S and TM at Time 0 were significantly higher in patients compared with controls. After 3 months of therapy, decreased levels were noted in NO (Time 0 24.05 ± 6.01 mmol/l, Time 1 13.92 ± 3.40 mmol/l; p < 0.001) and sCD40L (Time 0 1685.33 ± 866 pg/ml, Time 1 1055.11 ± 630.6 pg/ml; p = 0.017). In contrast, sP-S was significantly increased (Time 0 88.36 ± 47.76 ng/ml, Time 1 147.21 ± 94.43 ng/ml; p = 0.021). All patients remained stable in WHO class III, and in 9 patients we noted an improvement in 6-MWT. A correlation was found between Δ of RVSP and 6-MWT (r2= 0.5355, p < 0.001) as well as between Δ-sP-S and both Δ-6-MWT and Δ-RVSP. An increase sP-S level was found in 89% of nonresponder patients, whereas 55% of responders showed a stable or reduced sP-S level (p = 0.016 responder vs nonresponder).

Conclusion.

Treatment with bosentan for 3 months induced a beneficial effect by restoring endothelial function through a decrease in the markers of endothelial cell activity, leading to stabilization or improvement of severe PAH.

Pulmonary arterial hypertension in children: a medical update

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by a progressive pulmonary vasculopathy with ensuing right heart failure if left untreated. In the 1980's, prior to the current treatment era, idiopathic pulmonary arterial hypertension (IPAH) carried a poor prognosis with a 10 month median survival for children after diagnosis. However, in 1995 continuous intravenous epoprostenol was approved for the treatment of severe PAH, improving hemodynamics, quality of life, exercise capacity, functional class and survival. In the past decade there have been further advances in the treatment of PAH; however, there is still no cure. While much of the groundbreaking clinical research has been performed in adults, children have also seen the benefits of PAH novel therapies. The target population among pediatric patients is expanding with the recent recognition of pulmonary hypertension as a risk factor for sickle cell disease patients. With rapid advances, navigating the literature becomes challenging. A comprehensive review of the most recent literature over the past year on available and emerging novel therapies as well as an approach to target pediatric populations provides insights into the management of pediatric PAH patients.

Pulmonary arterial hypertension in children: a medical update

PURPOSE OF REVIEW

With rapid advances in the understanding and treatment of pulmonary arterial hypertension, navigating the pediatric literature becomes challenging. A comprehensive review of the most recent literature over the past year on available and emerging novel therapies as well as an approach to target pediatric populations will provide insight into the current management of pediatric pulmonary hypertension patients.

RECENT FINDINGS

Recent therapeutic advances have significantly improved the prognosis for children with pulmonary arterial hypertension. Pediatric pulmonary arterial hypertension continues to be a serious condition, however, which is extremely challenging to manage. There are also new target groups, such as those with sickle cell disease, congenital diaphragmatic hernia and Eisenmenger syndrome who may be candidates for treatments previously used for idiopathic pulmonary arterial hypertension patients.

SUMMARY

The data in children are often limited to case reports as many of those described here. Thus, the reader needs to be cautious about the interpretation of such small uncontrolled studies. While many of these data support the rationale for using novel agents for children with pulmonary arterial hypertension, further controlled and well designed studies are necessary to assess the true impact of these agents on various subgroups of children with pulmonary arterial hypertension.

[Treatment of systemic sclerosis]

Treatment of systemic sclerosis is based upon 3 types of medications modifiers of disease: drugs which prevent vascular damage, antifibrotric agents, and immunomodulators and immunosupressors. Drugs that prevent vascular damage such as: calcium antagonists, prostaglandins analogues, receptors of endothelin blockers (bosentan), inhibitors of angiotensin converting enzyme, receptors of angiotensin antagonists and inhibitors of 5'-phosphodiesterase have been successful in treating the Raynaud's phenomenon, renal crisis and pulmonary arterial hypertension. In contrast, the results of treatment of fibrosis are discouraging and the D-penicilamine continues being a matter of controversy. The immunosupressor therapy with cyclophosphamide and the transplant of hematopoietic cells, may be beneficial. The knowledge of the pathogenesis of systemic sclerosis to molecular level will lead to new treatment strategies.

Emerging treatments for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterised by a progressive pulmonary vasculopathy with ensuing right heart failure if left untreated. In the 1980s, prior to the current treatment era, idiopathic PAH carried a very poor prognosis, with a median survival of 2.8 years from the time of diagnosis. Since then, continuous intravenous epoprostenol has been used for the treatment of severe PAH with tremendous success, improving haemodynamics, quality of life, exercise capacity, functional class and even survival. In addition, in the past 5 years there have been several new advances in the treatment of PAH; however, there is still no cure. A better understanding of how the currently available agents work together is essential to optimise the long-term care of patients with PAH. Ultimately, additional agents that target the underlying pulmonary vasculopathy and endothelial abnormalities are necessary to cure this fatal disease. This comprehensive review of the currently available and emerging novel therapies provides insight into future management of PAH patients.

[Bosentan for treatment of active digital ulcers in patients with systemic sclerosis]

OBJECTIVES

To describe the effect of bosentan and its dual inhibition of endothelin-1 ETA and ETB receptors on digital ulcers in patients with systemic sclerosis (SSc).

METHODS

Patients receiving bosentan for SSc-related digital ulcers were identified in eight centers, and their characteristics and follow-up were recorded.

RESULTS

Nine (six with diffuse and three with limited cutaneous forms of SSc) patients (median age: 54 years) had received bosentan for digital ulcers. Complete healing occurred in seven (median time to improvement: 4 weeks). Another experienced a significant decrease in the number of ulcers (from 22 to 5) in 8 weeks, while one had no improvement. After a median follow-up of 24.3 months, only one recurrence was observed. Raynaud phenomenon improved in all but one patient.

DISCUSSION

These data suggest that some patients may benefit from bosentan to treat digital ulcers. The short time to healing in these patients with rather chronic ulcers argues strongly in favor of its use. These results also strengthen the evidence that endothelin-1 plays an important role in the vascular manifestations of SSc.

CONCLUSION

Bosentan can be effective in the treatment of digital ulcers in some SSc patients with SSc, probably especially those involving substantial ischemia. Bosentan is not a first-line drug in this indication yet and must be carefully used by specialists in SSc. Forthcoming results from the international RAPIDS-2 study should clarify the indications for bosentan in the treatment of SSc-related digital ulcers.

Pulmonary Involvement in Systemic Sclerosis

Scleroderma, also known as progressive systemic sclerosis (SSc), is a multisystem autoimmune disorder characterized by inflammation and fibrosis involving the skin as well as internal organs such as the vasculature, esophagus, and the respiratory tract. Pulmonary involvement consists most often of interstitial fibrosis and pulmonary vascular disease leading to pulmonary arterial hypertension (PAH). Bronchiectasis is an uncommon pulmonary manifestation of systemic sclerosis. Pulmonary hemorrhage with acute renal failure and diffuse alveolar hemorrhage in the absence of a history of renal involvement or penicillamine intake have rarely been reported in patients with systemic sclerosis.On high resolution CT, evidence of interstitial disease is seen in approximately 90% of patients, the main findings being a fine reticular pattern involving the subpleural regions of the lower lobe. Other common findings include ground-glass opacities, honeycombing, and parenchymal micronodules. The most distinctive pulmonary histologic findings in patients with scleroderma are the vascular changes found in PAH in the absence of significant interstitial fibrosis.There is no strong evidence that any drug alters the course of the two main types of lung disease in systemic sclerosis. This apparent failure of therapy may reflect the fact that pulmonary involvement is usually identified at an established or late stage. It has been suggested that, for fibrosing alveolitis, corticosteroids are most effective if given in combination with cyclophosphamide. In some patients with SSc, PAH has been considered as a major cause of morbidity and mortality. Centrally infused prostacyclin (epoprostenol) and its subcutaneously infused analog treprostinil improve hemodynamics, as well as the quality of life and survival in these patients. Iloprost has also shown a positive effect on PAH in SSc patients. More recently, bosentan, an endothelin receptor antagonist, has proved effective in controlling PAH after 6 months' treatment. Sildenafil has been used as a selective pulmonary vasodilator in SSc patients with isolated PAH. This drug decreased mean pulmonary artery pressure and pulmonary vascular resistance, and increased cardiac output, with much improvement of the physical condition of the patients. Lung transplant can be considered as a last option.Clinicians must be aware of the possibility of lung disease in patients with SSc so that it can be treated as early as possible.

Endothelin-1 response to mental stress in early ischemic lesions of the extremities due to systemic sclerosis

We studied circulating levels of endothelin-1, catecholamines and nitric oxide after a mental arithmetic test in 14 patients with early ischemic lesions of the extremities due to systemic sclerosis and slightly impaired peripheral vascular flow. The test induced an increase (P<0.01) in blood pressure, heart rate, endothelin-1 and catecholamine levels, whereas it did not change the low basal levels of nitric oxide. In healthy subjects (n=20) the test significantly (P<0.01) decreased endothelin-1 without affecting nitric oxide. The low basal levels of nitric oxide and the high plasma concentration of endothelin-1 after psychological stress cannot be explained by an impaired release from the limited ischemic lesions alone. This suggests a diffuse microvascular derangement that aggravates the course of peripheral microvascular ischemic lesions.

A new era in the management of pulmonary arterial hypertension related to scleroderma: endothelin receptor antagonism

Evidence suggests that endothelin may have a fundamental role in scleroderma pathogenesis, including pulmonary arterial hypertension (PAH)--a leading cause of death in patients with scleroderma. Development of a new class of drug, endothelin receptor antagonists, heralds an improved outlook for patients with scleroderma and related diseases. Heightened vigilance towards early detection of PAH in scleroderma and a multidisciplinary approach to diagnosis and treatment may improve clinical outcomes for these patients.

Medical therapy for pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines

Pulmonary arterial hypertension (PAH) is often difficult to diagnose and challenging to treat. Untreated, it is characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and death. The past decade has seen remarkable improvements in therapy, driven largely by the conduct of randomized controlled trials. Still, the selection of most appropriate therapy is complex, and requires familiarity with the disease process, evidence from treatment trials, complicated drug delivery systems, dosing regimens, side effects, and complications. This chapter will provide evidence-based treatment recommendations for physicians involved in the care of these complex patients. Due to the complexity of the diagnostic evaluation required, and the treatment options available, it is strongly recommended that consideration be given to referral of patients with PAH to a specialized center.

Opioid peptide response to spinal cord stimulation in chronic critical limb ischemia

Twelve patients with chronic critical limb ischemia in whom a spinal cord stimulation (SCS) system had been implanted for at least one year had increased microvascular flow and achieved healing of trophic acral lesions. After switching off the system, the clinical improvement persisted for 10 days and the neurohormonal pattern showed high plasma values of beta-endorphin and Met-enkephalin, normal dynorphin B, endothelin-1 and catecholamines, and low nitric oxide. Met-enkephalin levels were further increased (P < 0.01) immediately after switching on the electrical stimulation again. The persistence of high plasma opioid levels after switching off the spinal cord stimulation explains the absence of subjective complaints and suggests an involvement of opioids in the regulation and improvement of the microcirculation.

Pulmonary hypertension associated with connective tissue disease

Pulmonary arterial hypertension is a life threatening complication of several connective tissue diseases including scleroderma (both diffuse and limited scleroderma, or the CREST syndrome--calcinosis cutis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangectasia), systemic lupus erythomatosis (SLE), mixed connective tissue disease (MCTD), and less commonly, rheumatoid arthritis (RA) and dermatomyositis/polymyositis. This report reviews the occurrence of this complication, potential etiologies, clinical presentation, and treatment options.

Bosentan therapy for pulmonary arterial hypertension

BACKGROUND

Endothelin-1 is a potent vasoconstrictor and smooth-muscle mitogen. In a preliminary study, the orally administered dual endothelin-receptor antagonist bosentan improved exercise capacity and cardiopulmonary hemodynamics in patients with pulmonary arterial hypertension. The present trial investigated the effect of bosentan on exercise capacity in a larger number of patients and compared two doses.

METHODS

In this double-blind, placebo-controlled study, we randomly assigned 213 patients with pulmonary arterial hypertension (primary or associated with connective-tissue disease) to receive placebo or to receive 62.5 mg of bosentan twice daily for 4 weeks followed by either of two doses of bosentan (125 or 250 mg twice daily) for a minimum of 12 weeks. The primary end point was the degree of change in exercise capacity. Secondary end points included the change in the Borg dyspnea index, the change in the World Health Organization (WHO) functional class, and the time to clinical worsening.

RESULTS

At week 16, patients treated with bosentan had an improved six-minute walking distance; the mean difference between the placebo group and the combined bosentan groups was 44 m (95 percent confidence interval, 21 to 67; P<0.001). Bosentan also improved the Borg dyspnea index and WHO functional class and increased the time to clinical worsening.

CONCLUSIONS

The endothelin-receptor antagonist bosentan is beneficial in patients with pulmonary arterial hypertension and is well tolerated at a dose of 125 mg twice daily. Endothelin-receptor antagonism with oral bosentan is an effective approach to therapy for pulmonary arterial hypertension.

Effects of the dual endothelin-receptor antagonist bosentan in patients with pulmonary hypertension: a randomised placebo-controlled study

BACKGROUND

Endothelin 1, a powerful endogenous vasoconstrictor and mitogen, might be a cause of pulmonary hypertension. We describe the efficacy and safety of bosentan, a dual endothelin-receptor antagonist that can be taken orally, in patients with severe pulmonary hypertension.

METHODS

In this double-blind, placebo-controlled study, 32 patients with pulmonary hypertension (primary or associated with scleroderma) were randomly assigned to bosentan (62.5mg taken twice daily for 4 weeks then 125 mg twice daily) or placebo for a minimum of 12 weeks. The primary endpoint was change in exercise capacity. Secondary endpoints included changes in cardiopulmonary haemodynamics, Borg dyspnoea index, WHO functional class, and withdrawal due to clinical worsening. Analysis was by intention to treat.

FINDINGS

In patients given bosentan, the distance walked in 6 min improved by 70 m at 12 weeks compared with baseline, whereas it worsened by 6 m in those on placebo (difference 76 m [95% CI 12-139], p=0.021). The improvement was maintained for at least 20 weeks. The cardiac index was 1.0 L min(-1) m(-2) (95% CI 0.6-1.4, p<0.0001) greater in patients given bosentan than in those given placebo. Pulmonary vascular resistance decreased by 223 dyn s cm(-)(5) with bosentan, but increased by 191 dyn s cm(-5) with placebo (difference -415 [-608 to -221], p=0.0002). Patients given bosentan had a reduced Borg dyspnoea index and an improved WHO functional class. All three withdrawals from clinical worsening were in the placebo group (p=0.033). The number and nature of adverse events did not differ between the two groups.

INTERPRETATION

Bosentan increases exercise capacity and improves haemodynamics in patients with pulmonary hypertension, suggesting that endothelin has an important role in pulmonary hypertension.

Novel therapy in the treatment of scleroderma

While the biology of the pathogenesis of scleroderma is continually being better understood, there still is no single agent or therapeutic combination that has a clear impact on the disease process. Traditional medications (colchicine, potassium aminobenzoate (potaba), D-penicillamine) are disappointing in clinical practice despite anecdotal evidence of benefit. Furthermore, the most popular traditional drug, D-penicillamine, failed to clearly show benefit when tested in a well-designed clinical trial comparing conventional high dose with a very low dose (125 mg po. every other day [corrected]) [1]. Currently, most success in managing scleroderma and improving quality of life is secondary to organ-specific therapy, such as management of a renal crisis with an ACE inhibitor, treatment of Raynaud's phenomenon with calcium channel blockers, or control of serious gastrointestinal reflux disease with a proton pump inhibitor. In this review we will focus on novel therapies that are currently being tested in the treatment of scleroderma and have the potential of modifying the disease process and overall clinical outcome. We have attempted to review the rationale for each agent, recognising that its true biological effect will only be determined in clinical trials.

Losartan therapy for Raynaud's phenomenon and scleroderma: clinical and biochemical findings in a fifteen-week, randomized, parallel-group, controlled trial

OBJECTIVE

To compare the efficacy and tolerability of losartan, an antagonist of angiotensin II receptor type 1, with nifedipine for the treatment of primary and secondary Raynaud's phenomenon (RP) in a pilot study.

METHODS

In a randomized, parallel-group, controlled trial, patients with primary RP (n = 25) or RP secondary to systemic sclerosis (SSc [scleroderma]; n = 27) were allocated to receive 12 weeks' treatment with either losartan (50 mg/day) or nifedipine (40 mg/day). Primary outcome variables were the severity and frequency of RP episodes and findings on vascular measurements, including thermography and laser Doppler flowmetry. Serum levels of soluble adhesion molecules, endothelin 1, fibrinogen, von Willebrand factor, and procollagen type I N-terminal propeptide (PINP) were also measured.

RESULTS

There was a reduction in the severity of RP episodes following treatment with losartan and with nifedipine, but this effect was greater in the losartan arm of the study (P<0.05): episode frequency was reduced only in the losartan group (P<0.01 versus baseline). Symptomatic improvement was associated with a significant reduction in soluble vascular cell adhesion molecule 1 and PINP (P<0.01). Subgroup analysis suggested that although these biochemical changes occurred mainly in SSc patients, the clinical benefit was greater in the primary RP group.

CONCLUSION

This study confirms the tolerability of short-term treatment of RP with losartan, and our data suggest its clinical benefit. Further evaluation of this drug as a long-term treatment for SSc-associated RP should be considered, since it may have additional disease-modifying potential.

A case-control study of candidate vasoactive mediator genes in primary Raynaud's phenomenon

OBJECTIVES

To elucidate possible genetic factors involved in the pathogenesis of primary Raynaud's phenomenon (RP) and to determine the demographic features.

METHODS

The allele frequencies of known polymorphisms in four vasoactive candidate genes, eNOS, BKRG, ET-1 and the ETA receptor genes, were compared in a phenotypically homogeneous group of patients with primary RP and a normal control population.

RESULTS

In patients with primary RP, there was a higher reporting of both a family history of RP than in controls (45.3% vs 3.1%; P<0.0001) and a personal history of migraine (32.6% vs 7.2%; P<0.0001). No significant differences in allele frequencies of the candidate genes were found.

CONCLUSIONS

These findings support the concept that genetic susceptibility exists in primary RP. The high prevalence of migraine suggests that primary RP is part of a more widespread disorder of vascular tone. These findings do not suggest that common molecular variants of these candidate genes are involved in primary RP.

Short-term estrogen administration improves abnormal endothelial function in women with systemic sclerosis and Raynaud's phenomenon

BACKGROUND

Morphologic changes of the vascular endothelium are common in patients with systemic sclerosis and Raynaud's phenomenon. The aim of this study was to evaluate the endothelium-dependent vasodilatation and endothelium-independent vasodilatation and to examine the effects of short-term estrogen administration on vascular responses in these patients.

METHODS AND RESULTS

The study included 12 female patients with systemic sclerosis and Raynaud's phenomenon (aged 49+/-14 years) and 12 age- and sex-matched healthy control subjects. With the use of high-resolution ultrasound imaging, brachial artery diameter was measured at rest, during reactive hyperemia (endothelium-dependent response), and after administration of sublingual nitroglycerin (endothelium-independent dilatation). Intima-media thickness of the common carotid artery was also measured. Baseline diameter was similar in patients and control subjects; intima-media thickness was significantly higher in patients (0.83+/-0.3 vs 0.46+/-0.2 mm, P= .002) than in control subjects. Flow-mediated dilatation was reduced in patients (3.6%+/-7% vs 11.9%+/- 4.6%, P = .003); endothelium-independent dilatation also was reduced in patients with Raynaud's phenomenon (14%+/-7% vs 23%+/-6%, P= .003). Vascular responses in 10 patients were examined 15 minutes after administration of conjugated estrogens (25 mg intravenously); there was a significant increase of endothelium-dependent dilatation after estrogen administration (1.7%+/-4% to 6.3%+/-4%, P= .01), whereas endothelium-independent dilatation did not change (13.4%+/-8% to 15.5%+/-7%, not significant).

CONCLUSIONS

Endothelium-dependent vasodilatation and endothelium-independent vasodilatation are impaired in patients with Raynaud's phenomenon secondary to systemic sclerosis, whereas intima-media thickness is increased. Short-term estrogen administration can improve endothelial dysfunction in this group of patients.

The effect of electrical acupuncture-stimulation therapy using thermography and plasma endothelin (ET-1) levels in patients with progressive systemic sclerosis (PSS)

In all 11 patients with progressive systemic sclerosis (PSS; Barnett type I, 2; type II, 5; type III, 4 cases; male 1; female 10 cases; 45.2 +/- 10.2 years-old), 6 cases of scleroderma spectrum disorders (SSD, male 1; female 5 cases; 51.2 +/- 13.2 years-old) and 7 healthy controls (HC, male 1; female 6 cases; 43.1 +/- 8.4 years-old) were entered to be examined. The plasma endothelin-1 (ET-1) levels of PSS, SSD and HC were 1.98 +/- 0.69, 1.76 +/- 0.39 and 1.15 +/- 0.38 pg/ml, respectively. After the stimulation with the low frequency electrical current, electrical acupuncture, for unilateral side of hand/arm (30 min), the plasma ET-1 levels decreased in 10 cases of PSS treated (1.61 +/- 0.45 pg/ml), but no change of plasma serotonin levels. In 4 of 6 cases of SSD, plasma ET-1 levels increased (2.06 +/- 0.39 pg/ml), however, nitrate levels increased and serotonin decreased in 3 of 5 cases of SSD. In 6 cases of HC treated with the electrical acupuncture, the plasma ET-1 levels increased (1.72 +/- 0.58 pg/ml). Thermographically, 9 of 11 cases of PSS and 5 of 6 cases of SSD showed temporally temperature-elevation of hand/fingers not only in treated sides, but also in non treated sides, although none of 7 HC showed temperature-elevation of hands/fingers. The decrease in plasma ET-1 levels due to the electrical acupuncture was thought to induce the vasodilatation and elevate the surface temperature in patients with PSS. These results will provide an excellent basis to study the efficacy of electrical acupunctural stimulation.

[Physiopathology of Raynaud phenomenon: current data]

Despite over a century of investigation, the pathophysiology of Raynaud's phenomenon remains an enigma. The two main theories of the cause of digital artery vasospasm are increased activity of the sympathetic nervous system and a local fault in the digital vasculature. An increased sensitivity and/or concentration of alpha-2 adrenoreceptors is suggested. The activation of serotoninergic receptors may play a role in the maintenance of vasospasm. The recently discovered increase in the vasoconstrictive peptide endothelin-1 and the quantitative deficit in the potent vasodilating calcitonin gene-related peptide may lead to a better understanding of vasospasm mechanisms and open the field for new therapeutical approaches to Raynaud's phenomenon.

Peripheral vasoactivity in familial hypercholesterolemic subjects treated with heparin-induced extracorporeal LDL precipitation (HELP)

Hypercholesterolemia is associated with abnormalities in arterial vasoactivity which can be reversed with cholesterol-reducing therapies. Heparin-induced extracorporeal LDL precipitation (HELP), an invasive method for treating refractory hypercholesterolemia, causes regression of both xanthomas and atherosclerosis, but its effect on vasoactivity has not been investigated. We tested the effects of HELP on vasoactivity with an ultrasound system for continuous measurement of arterial flow velocity and end-diastolic diameter. We measured brachial artery vasoactivity before, during, and after a 5 min forearm vascular occlusion. Vasoactivity measurements were acquired from 6 subjects with familial hypercholesterolemia (FH) who had been treated chronically with HELP, immediately before and after each of 4 treatments, and from 12 age- and sex-matched normocholesterolemic subjects (2 matched with each HELP subject). Peak arterial dilation after cuff release, relative to the pre-occlusion diameter, was similar for the pre-treatment, post-treatment, and normocholesterolemic groups (0.29 mm pre-treatment, 0.30 mm post-treatment and 0.33 mm normocholesterolemic, P = NS). The slope of arterial diameter during occlusion was also similar for the three groups (-0.10 microm/s pre-treatment, 0.02 microm/s post-treatment, and 0.06 microm/s normocholesterolemic, P = NS). These two parameters are known to be decreased in hypercholesterolemic subjects to an extent which could be readily detected by the power of this study. Interestingly, one homozygous FH subject consistently demonstrated significant improvement in these two parameters immediately after HELP, suggesting an individual difference in arterial physiology. On average, FH patients treated chronically with HELP have similar vasoactivity to age- and sex-matched subjects with low risk for atherosclerosis. This result, in light of the many studies that have associated hypercholesterolemia with abnormal vasoactivity, suggests that chronic HELP therapy improves vasoactivity in patients with severe hypercholesterolemia.