The vasculopathy of Raynaud's phenomenon and scleroderma

Endothelial Progenitor Cells in Autoimmune Disorders

Circulating endothelial progenitor cells (EPCs) were first described in 1997 by Asahara et al. as "putative endothelial cells" from human peripheral blood. The study of endothelial progenitors is also intensifying in several pathologies associated with endothelial damage, including diabetes, myocardial infarction, sepsis, pulmonary arterial hypertension, obstructive bronchopneumopathy and transplantation. EPCs have been studied in several autoimmune diseases with endothelial involvement such as systemic lupus erythematosus, thrombotic thrombocytopenic purpura, antineutrophil cytoplasmic antibodies, vasculitis, rheumatoid arthritis, Goujerot-Sjögren and antiphospholipid syndrome. Factors involved in endothelial damage are due to overexpression of pro-inflammatory cytokines and/or autoantibodies. Management of these pathologies, particularly the long-term use of glucocorticoids and methotrexate, promote atherosclerosis. A lack of standardized assessment of the number and function of EPCs represents a serious challenge for the use of EPCs as prognostic markers of cardiovascular diseases (CVD). The objective of this review was to describe EPCs, their properties and their involvement in several autoimmune diseases.

Hyperspectral imaging in systemic sclerosis-associated Raynaud phenomenon

BACKGROUND/PURPOSE

Lack of robust, feasible, and quantitative outcomes impedes Raynaud phenomenon (RP) clinical trials in systemic sclerosis (SSc) patients. Hyperspectral imaging (HSI) non-invasively measures oxygenated and deoxygenated hemoglobin (oxyHb and deoxyHb) concentrations and oxygen saturation (O2 sat) in the skin and depicts data as oxygenation heatmaps. This study explored the potential role of HSI in quantifying SSc-RP disease severity and activity.

METHODS

Patients with SSc-RP (n = 13) and healthy control participants (HC; n = 12) were prospectively recruited in the clinic setting. Using a hand-held camera, bilateral hand HSI (HyperMed™, Waltham, MA) was performed in a temperature-controlled room (22 °C). OxyHb, deoxyHb, and O2 sat values were calculated for 78-mm2 regions of interest for the ventral fingertips and palm (for normalization). Subjects underwent a cold provocation challenge (gloved hand submersion in 15 °C water bath for 1 min), and repeated HSI was performed at 0, 10, and 20 min. Patients completed two patient-reported outcome (PRO) instruments: the Raynaud Condition Score (RCS) and the Cochin Hand Function Scale (CHFS) for symptom burden assessment. Statistical analyses were performed using the Mann-Whitney U test and a mixed effects model (Stata, College Station, TX).

RESULTS

Ninety-two percent of participants were women in their 40s. For SSc-RP patients, 69% had limited cutaneous SSc, the mean ± SD SSc duration was 11 ± 5 years, and 38% had prior digital ulcers-none currently. Baseline deoxyHb was higher, and O2 sat was lower, in SSc patients versus HC (p < 0.05). SSc patients had a greater decline in oxyHb and O2 sat from baseline to time 0 (after cold challenge) with distinct rewarming oxyHb, O2 sat, and deoxyHb trajectories versus HCs (p < 0.01). There were no significant correlations between oxyHb, deoxyHb, and O2 sat level changes following cold challenge and RCS or CHFS scores.

CONCLUSION

Hyperspectral imaging is a feasible approach for SSc-RP quantification in the clinic setting. The RCS and CHFS values did not correlate with HSI parameters. Our data suggest that HSI technology for the assessment of SSc-RP at baseline and in response to cold provocation is a potential quantitative measure for SSc-RP severity and activity, though longitudinal studies that assess sensitivity to change are needed.

Raynaud's Phenomenon: Reviewing the Pathophysiology and Management Strategies

Raynaud's phenomenon (RP) is a multifactorial vasospastic disorder characterized by a transient, recurrent, and reversible constriction of peripheral blood vessels. RP is documented to affect up to 5% of the general population, but variation in its prevalence is commonly recognized owing to many factors, including varied definitions, gender, genetics, hormones, and region. Furthermore, RP may be idiopathic or be a clinical manifestation of an underlying illness. Patients with RP classically describe a triphasic discoloration of the affected area, beginning with pallor, followed by cyanosis, and finally ending with erythema. This change in color spares the thumb and is often associated with pain. Each attack may persist from several minutes to hours. Moreover, the transient cessation of blood flow in RP is postulated to be mediated by neural and vascular mechanisms. Both structural and functional alterations observed in the blood vessels contribute to the vascular abnormalities documented in RP. However, functional impairment serves as a primary contributor to the pathophysiology of primary Raynaud's. Substances like endothelin-1, angiotensin, and angiopoietin-2 play a significant role in the vessel-mediated pathophysiology of RP. The role of nitric oxide in the development of this phenomenon is still complex. Neural abnormalities resulting in RP are recognized as either being concerned with central mechanisms or peripheral mechanisms. CNS involvement in RP may be suggested by the fact that emotional distress and low temperature serve as major triggers for an attack, but recent observations have highlighted the importance of locally produced factors in this regard as well. Impaired vasodilation, increased vasoconstriction, and several intravascular abnormalities have been documented as potential contributors to the development of this disorder. RP has also been observed to occur as a side effect of various drugs. Recent advances in understanding the mechanism of RP have yielded better pharmacological therapies. However, general lifestyle modifications along with other nonpharmacological interventions remain first-line in the management of these patients. Calcium channel blockers, alpha-1 adrenoreceptor antagonists, angiotensin-converting enzyme inhibitors, nitric oxide, prostaglandin analogs, and phosphodiesterase inhibitors are some of the common classes of drugs that have been found to be therapeutically significant in the management of RP. Additionally, anxiety management, measures to avoid colder temperatures, and smoking cessation, along with other simple modifications, have proven to be effective non-drug strategies in patients experiencing milder symptoms.

Correlation of retinal and choroidal microvascular impairment in systemic sclerosis

Purpose

To investigate the correlation between retinal and choroidal microperfusion in patients with systemic sclerosis (SSc) using optical coherence tomography angiography (OCTA).

Methods

In this cross-sectional study SSc patients without clinical evidence of ocular involvement and healthy, age- and sex-matched volunteers were recruited. Participants underwent specific rheumatological and ophthalmological examinations, including optical coherence tomography (OCT) and OCTA. Retinal and choroidal thicknesses as well as perfusion of the retina and the choroidal sublayers were evaluated.

Results

A total of 15 SSc patients (30 eyes) with a median disease duration of 60 months and 15 matched, healthy controls (30 eyes) were recruited. OCT data revealed a significantly lower macular volume, as well as Sattler’s layer and Haller’s layer thickness in SSc patients compared to controls. In OCTA analysis, the perfusion of both retinal plexus as well as Sattler’s and Haller’s layer were significantly reduced in the SSc group. Patients with a disease duration of more than 60 months showed a statistically significant positive correlation between retinal and choroidal malperfusion, while those with a shorter disease duration did not.

Conclusion

OCTA analysis confirmed impairment of retinal and choroidal microperfusion in SSc patients, supporting the hypothesis of wide spreading vascular injury. In early stages, either the retinal or the choroidal perfusion seems to be involved, while later on, vascular impairment affects both tissues alike. Both, retinal and choroidal examinations should be considered as soon as the diagnosis of SSc is made, to avoid missing out on early alterations.

The Expression and Role of Hypoxia-induced Factor-1α in Human Tenon's Capsule Fibroblasts under Hypoxia

PURPOSE

To determine the expression of hypoxia-induced factor-1α (HIF-1α) and its downstream factors in human Tenon's capsule fibroblasts (HTFs) and changes in HTFs biological functions, we explored the role of HIF-1α in HTFs under hypoxia to provide a basis for studying the regulation of HIF-1α in wound healing after glaucoma surgery.

MATERIALS AND METHODS

we established HTFs hypoxia model in vitro, meanwhile the HIF-1α agonist VH298 or inhibitor KC7F2 was added to HTFs, and the normoxia group was used as a control. Western blot, immunofluorescence and ELISA were used to detect the expression of HIF-1α, vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), Smads and collagen I. The proliferation of HTFs was quantified by cell counting kit-8, and cell migration was tested by healing scratch test.

RESULTS

HIF-1α protein expression increased under hypoxia, peaked from 4-24 h, and then decreased. The secretion of VEGF and TGF-β increased with prolonged hypoxia time. VH298 and KC7F2 upregulated and downregulated the levels of VEGF and TGF-β, respectively, suggesting that HIF-1α upregulates and downregulates the levels of VEGF and TGF-β in HTFs under hypoxia, respectively. HIF-1α upregulated the proliferation, migration and collagen synthesis of HTFs under hypoxia.

CONCLUSIONS

Regulating HIF-1α and its downstream factors effectively regulated HTFs proliferation, migration and collagen synthesis. HIF-1α is a promising regulator in the study of wound healing after glaucoma surgery.

Targeting Hypoxia Inducible Factors-1α As a Novel Therapy in Fibrosis

Fibrosis, characterized by increased extracellular matrix (ECM) deposition, and widespread vasculopathy, has the prominent trait of chronic hypoxia. Hypoxia inducible factors-1α (HIF-1α), a key transcriptional factor in response to this chronic hypoxia, is involved in fibrotic disease, such as Systemic sclerosis (SSc). The implicated function of HIF-1α in fibrosis include stimulation of excessive ECM, vascular remodeling, and futile angiogenesis with further exacerbation of chronic hypoxia and deteriorate pathofibrogenesis. This review will focus on the molecular biological behavior of HIF-1α in regulating progressive fibrosis. Better understanding of the role for HIF-1α-regulated pathways in fibrotic disease will accelerate development of novel therapeutic strategies that target HIF-1α. Such new therapeutic strategies may be particularly effective for treatment of the prototypic, multisystem fibrotic, autoimmune disease SSc.

Postocclusive Hyperemia Measured with Laser Doppler Flowmetry and Transcutaneous Oxygen Tension in the Diagnosis of Primary Raynaud's Phenomenon: A Prospective, Controlled Study

The aim of this study was to measure the sensitivity and specificity of transcutaneous oxygen tension and postocclusive hyperemia testing using laser Doppler flowmetry in patients with primary Raynaud's phenomenon. One hundred patients and one hundred controls were included in the study. Baseline microvascular blood flow and then time to peak flow following occlusion were measured using laser Doppler flowmetry. Afterwards, the transcutaneous oxygen tension was recorded. The sensitivities of baseline microvascular blood flow, postocclusive time to peak flow, and transcutaneous oxygen tension were 79%, 79%, and 77%, respectively. The postocclusive time peak flow had a superior specificity of 90% and area under the curve of 0.92 as compared to 66% and 0.80 for baseline microvascular flow and 64% and 0.76 for transcutaneous oxygen tension. Time to postocclusive peak blood flow measured by laser Doppler flowmetry is a highly accurate test for differentiating patients with primary Raynaud's phenomenon from healthy controls.

Endocan, Novel Potential Biomarker for Systemic Sclerosis: Results of a Pilot Study

BACKGROUND

Systemic sclerosis (Ssc) is an autoimmune disease characterized by vascular alterations of small arteries and microvessels with subsequent tissue fibrosis. Endocan is expressed by endothelial cells and associated with endothelial dysfunction; therefore it could be a potential biomarker for Ssc patients.

METHODS

Twenty-one Ssc patients and 20 sex- and age-matched healthy controls were recruited for the study. Serum endocan levels were determined using ELISA method in all patients and controls.

RESULTS

Serum endocan levels were superior in Ssc patients (median 2.53 (1.10-7 ng/ml)) compared with controls (0.79 (0-2 ng/ml), P < 0.05). Higher serum endocan expression was seen in diffuse Ssc subset and associated with the presence of digital ulcers and daily Raynaud's phenomenon (P < 0.05). Higher serum endocan levels were associated with a modified Rodnan skin score >14 and longer disease duration (P < 0.05). Values of areas under the receiver operating curves showed that serum endocan had good discriminative power for Ssc diagnosis, differentiating diffuse from limited subset type and differentiating patients with modified Rodnan skin score above and under 14 (area under curve: 0.94, 0.81, 0.75, respectively).

CONCLUSION

The results of this pilot study suggest endocan as a potential biomarker for microvascular manifestations and complications in Ssc patients. These encouraging results could promote future prospective studies in order to determine the exact role played by endocan as a biomarker for Ssc.

Raynaud's phenomenon: new aspects of pathogenesis and the role of nailfold videocapillaroscopy

Raynaud's phenomenon (RP) refers to paroxysmal pallor or cyanosis of the digits of the hands or feet and, infrequently, the tips of the nose or ears (acral parts) owing to cold-induced vasoconstriction of the digital arteries, precapillary arterioles, and cutaneous arteriovenous shunts.

Raynaud's phenomenon reflects an exaggeration of normal central and local vasomotor responses to cold or emotion. Raynaud's phenomenon has been classified as primary or secondary, depending on whether it occurs as an isolated condition or is associated mainly with a connective tissue disease.

Dysregulation of autonomic and sensitive nerve fibers, functional and structural vessel changes, and intravascular alterations can be observed in the pathogenesis of RP.

Nailfold videocapillaroscopy (NVC) is the best non-invasive and repetitive diagnostic technique for detecting morpho-functional changes in the microcirculation. Nailfold videocapillaroscopy is accepted in early diagnosis and monitoring of primary and secondary RP.

The role of botulinum toxin in vasospastic disorders of the hand

Raynaud phenomenon may be a primary disorder or associated with a variety of other autoimmune processes. Raynaud phenomenon produces digital vasospasm, which can lead to ischemia and ulceration. The treatment of Raynaud phenomenon has been difficult because multiple medical treatments have not provided uniform resolution of symptoms. Many patients have turned to surgery and sympathectomies for the treatment of unrelenting vasospasm. Botulinum toxin has been shown to be an effective alternative to surgery, with a single treatment being capable of resolving pain and healing ulcer. This article reviews the use of botulinum toxin for the treatment of Raynaud phenomenon.

Intact calibers of retinal vessels in patients with systemic sclerosis

OBJECTIVE

A primary endothelial cell dysfunction is thought to be involved in systemic sclerosis (SSc)-associated fibroproliferative vasculopathy of the microcirculation and small arterioles, even in sites not affected by fibrosis. Because the role of fibroblasts in pathologic modifications and vascular wall remodeling is relatively unclear, and because the retina provides a unique opportunity to assess microcirculation in the absence of resident fibroblasts, we systematically evaluated retinal vessels in patients with SSc.

METHODS

Digital retinal images were obtained from both eyes of 93 consecutive patients with fully characterized SSc and 29 healthy controls matched 1:1 for age and sex with selected patients without diabetes, hypertension history, or antihypertensive treatment. Internal microvascular calibers (erythrocyte column width in μm) by central retinal arteriolar and venular equivalents and arteriolar to venular ratio were measured using validated software.

RESULTS

Arteriolar and venular calibers were similar in patients and their matched controls (mean ± SEM; 187 ± 2 vs 184 ± 3, p = 0.444, and 211 ± 2 vs 216 ± 3, p = 0.314, respectively). Both arteriolar and venular calibers and their ratio in patients with SSc were not associated with disease duration, extent of skin involvement, pulmonary fibrosis, digital ulcers or pitting scars, amputations, digital capillaroscopic findings, inflammatory indices, or autoantibodies.

CONCLUSION

The evidence that retinal microcirculation is spared in SSc suggests that fibroproliferative vasculopathy may depend on specific cellular or soluble factors not present in the retinal environment.

Decreased numbers of endothelial progenitor cells in patients in the early stages of systemic sclerosis

INTRODUCTION

Microangiopathy and endothelial dysfunction are present in the early stages of systemic sclerosis (SSc). Defective vasculogenesis mediated by bone marrow-derived endothelial progenitor cells (EPCs) might be involved in the vascular abnormalities found in SSc.

OBJECTIVES

To evaluate the circulating EPC levels and EPC subtypes via flow cytometry and early outgrowth colony-forming units (CFUs) in patients with SSc compared to healthy subjects.

METHODS

Thirty-nine female SSc patients (30 in the early stages of SSc) and 44 age-matched healthy women were included. Peripheral blood EPCs were quantified using flow cytometry and by counting the early outgrowth CFUs.

RESULTS

The EPCs quantified with flow cytometry and the CFU numbers were significantly lower in SSc patients than in control subjects (155.1 ± 95.1 vs. 241.3 ± 184.2 EPC/10(6) lymphomononuclear cells, p=0.011; 15.4 ± 8.6 vs. 23.5 ± 10.9 CFU, p<0.001; respectively), as well as in the group of patients in the early stages of SSc compared to the controls. Patients with digital ulcers had significantly higher CFU counts than those without ulcers (p=0.013). Among patients with the scleroderma pattern on nailfold capillaroscopy, patients with the late pattern had significantly lower EPC levels than those with the early and active patterns (p=0.046). There were no significant correlations of EPCs or CFU levels with RP duration.

CONCLUSIONS

The present study revealed decreased EPCs in SSc patients, including those with early disease onset. These findings suggest that defective vasculogenesis occurs in the early phases of the disease. Therefore, EPCs might be an important therapeutic target for the prevention of vascular complications in SSc patients.

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.

In silico modeling of human α2C-adrenoreceptor interaction with filamin-2

Vascular smooth muscle α2C-adrenoceptors (α2C-ARs) mediate vasoconstriction of small blood vessels, especially arterioles. Studies of endogenous receptors in human arteriolar smooth muscle cells (referred to as microVSM) and transiently transfected receptors in heterologous HEK293 cells show that the α2C-ARs are perinuclear receptors that translocate to the cell surface under cellular stress and elicit a biological response. Recent studies in microVSM unraveled a crucial role of Rap1A-Rho-ROCK-F-actin pathways in receptor translocation, and identified protein-protein interaction of α2C-ARs with the actin binding protein filamin-2 as an essential step in the process. To better understand the molecular nature and specificity of this interaction, in this study, we constructed comparative models of human α2C-AR and human filamin-2 proteins. Finally, we performed in silico protein-protein docking to provide a structural platform for the investigation of human α2C-AR and filamin-2 interactions. We found that electrostatic interactions seem to play a key role in this complex formation which manifests in interactions between the C-terminal arginines of α2C-ARs (particularly R454 and R456) and negatively charged residues from filamin-2 region between residues 1979 and 2206. Phylogenetic and sequence analysis showed that these interactions have evolved in warm-blooded animals.

A double-blind, randomized, placebo-controlled crossover trial of the α2C-adrenoceptor antagonist ORM-12741 for prevention of cold-induced vasospasm in patients with systemic sclerosis

OBJECTIVES

Our primary purpose was to evaluate the efficacy of the high-potency α2C-adrenoceptor antagonist ORM-12741 in the attenuation of a cold-induced reduction in finger blood flow and temperature in patients with RP secondary to SSc. Secondary objectives were to assess safety and tolerability.

METHODS

This was a phase IIa, randomized, double-blind, crossover, single-dose, placebo-controlled, single-centre study. Patients attended five times: initial screening, treatment visits 1-3 (each at least 1 week apart) and 1-2 weeks after the last treatment. At each treatment visit, each subject received a single oral dose of 30 mg or 100 mg of ORM-12741 or placebo. Thirty minutes later the subject underwent a cold challenge. Blood flow to the fingers was assessed by three methods [temperature by probe, laser Doppler imaging (LDI) and infrared thermography] performed before, during and after the cold challenge.

RESULTS

Twelve patients (10 female, mean age 58 years) were included. The area under the rewarming curve (LDI) of the right index finger (arbitrary flux units × time) was lower for both 30 mg (P = 0.043) and 100 mg (P = 0.025) of ORM-12741 compared with placebo, indicating delayed reperfusion. The time to 70% temperature recovery (middle finger probe) was longer with active than placebo treatment: mean (s.d.) values for placebo, 30 mg of ORM-12741 and 100 mg of ORM-12741 were 21.4 min (12.4), 25.7 min (12.2) and 26.9 min (13.9), respectively. Overall ORM-12741 was well tolerated.

CONCLUSION

ORM-12741 did not expedite recovery from a cold challenge in the fingers of patients with SSc.

TRIAL REGISTRATION

https://www.clinicaltrialsregister.eu/; no. 2010-024005-13.

Raynaud's phenomenon: from molecular pathogenesis to therapy

Raynaud's phenomenon (RP) is a well defined clinical syndrome characterized by recurrent episodes of digital vasospasm triggered by exposure to physical/chemical or emotional stress. RP has been classified as primary or secondary, depending on whether it occurs as an isolated condition (pRP) or is associated to an underlying disease, mainly a connective tissue disease (CTD-RP). In both cases, it manifests with unique "triple" (pallor, cyanosis and erythema), or "double" color changes. pRP is usually a benign condition, while sRP can evolve and be complicated by acral digital ulcers and gangrene, which may require surgical treatment. The pathogenesis of RP has not yet been entirely clarified, nor is it known whether autoantibodies have a role in RP. Even so, recent advances in our understanding of the pathophysiology have highlighted novel potential therapeutic targets. The aim of this review is to discuss the etiology, epidemiology, risk factors, clinical manifestations, recently disclosed pathogenic mechanisms underlying RP and their correlation with the available therapeutic options, focusing primarily on pRP and CTD-RP.

Acute retinal artery occlusion in systemic sclerosis: a rare manifestation of systemic sclerosis fibroproliferative vasculopathy

OBJECTIVES

To describe three patients with systemic sclerosis (SSc) who developed acute unilateral blindness in the absence of any common etiologic factor for blindness. In one patient, the affected eye required enucleation and was examined histopathologically.

METHODS

Following identification of the first patient with retinal artery occlusion at the Scleroderma Center of Thomas Jefferson University, every patient evaluated at the Center from May 2001 to December 2010 was prospectively assessed for the development of acute unilateral blindness. Two additional cases were identified. Here, we describe the clinical features, laboratory and ancillary examinations of the three patients with SSc who developed acute unilateral blindness and present the histopathological examination of one eye enucleated from one of the patients.

RESULTS

Clinical and angiographic studies were consistent with acute retinal artery occlusion. The histopathological studies showed severe retinal ischemic atrophy and concentric narrowing and fibrosis of small retinal vessels.

CONCLUSIONS

These findings suggest that acute retinal artery occlusion in these patients is a manifestation of the fibroproliferative vasculopathy characteristic of SSc.

Scleroderma therapy: clinical overview of current trends and future perspective

Systemic sclerosis is a chronic autoimmune condition with a complex pathogenesis and a high rate of mortality and morbidity. Internal organ involvement requires interdisciplinary approach in individual patient management. New discoveries in the pathogenesis of scleroderma herald a drastic change in the traditional outlook to therapy and have led to the development of the target-based approach in management. The challenge at present is to translate these advances in molecular mechanisms into well-designed clinical trials that will recognize potential disease-modifying therapies. This article is an evidence-based review of prevailing treatment options and future therapeutic targets in systemic sclerosis.

Cyclic AMP-Rap1A signaling activates RhoA to induce α(2c)-adrenoceptor translocation to the cell surface of microvascular smooth muscle cells

Intracellular signaling by the second messenger cyclic AMP (cAMP) activates the Ras-related small GTPase Rap1 through the guanine exchange factor Epac. This activation leads to effector protein interactions, activation, and biological responses in the vasculature, including vasorelaxation. In vascular smooth muscle cells derived from human dermal arterioles (microVSM), Rap1 selectively regulates expression of G protein-coupled α(2C)-adrenoceptors (α(2C)-ARs) through JNK-c-jun nuclear signaling. The α(2C)-ARs are generally retained in the trans-Golgi compartment and mobilize to the cell surface and elicit vasoconstriction in response to cellular stress. The present study used human microVSM to examine the role of Rap1 in receptor localization. Complementary approaches included murine microVSM derived from tail arteries of C57BL6 mice that express functional α(2C)-ARs and mice deficient in Rap1A (Rap1A-null). In human microVSM, increasing intracellular cAMP by direct activation of adenylyl cyclase by forskolin (10 μM) or selectively activating Epac-Rap signaling by the cAMP analog 8-pCPT-2'-O-Me-cAMP (100 μM) activated RhoA, increased α(2C)-AR expression, and reorganized the actin cytoskeleton, increasing F-actin. The α(2C)-ARs mobilized from the perinuclear region to intracellular filamentous structures and to the plasma membrane. Similar results were obtained in murine wild-type microVSM, coupling Rap1-Rho-actin dynamics to receptor relocalization. This signaling was impaired in Rap1A-null murine microVSM and was rescued by delivery of constitutively active (CA) mutant of Rap1A. When tested in heterologous HEK293 cells, Rap1A-CA or Rho-kinase (ROCK-CA) caused translocation of functional α(2C)-ARs to the cell surface (~4- to 6-fold increase, respectively). Together, these studies support vascular bed-specific physiological role of Rap1 and suggest a role in vasoconstriction in microVSM.

α2C-adrenoceptor modulators: a patent review

INTRODUCTION

α2-Adrenoceptors (α2-ARs) are membrane proteins belonging to the superfamily of GPCRs. Detailed studies have shown three different subtypes, namely α2A, α2B and α2C. Although numerous α2-AR ligands exist, only a small set of compounds have shown even a degree of selectivity among the three α2-AR subtypes. Moreover, these compounds suffer from binding to receptor sites outside the α2-AR subfamily. Efforts made to understand the biological significance of each α2-AR subtype have greatly been assisted by genetically engineered mice. The main results obtained suggest that α2C-AR stimulation may represent a therapeutic strategy to get an analgesic response with reduced sedative effects and undesirable changes in blood pressure due to α2A-AR activation.

AREAS COVERED

This review summarizes the patent literature about the development of α2C-AR modulators from 2000 to early 2010 and their therapeutic effects evoked by the interaction with this receptor subtype.

EXPERT OPINION

Over 90 patents have been deposited in the last 10 years regarding different methods of α2C-AR modulation (use of agonists or antagonists, nucleic acids and polypeptides) for diagnosis, prognosis and treatment of disorders involving this receptor. Nevertheless, despite the numerous published patents, ligands highly selective for the α2C-AR subtype, which continues to be enigmatic, are lacking.

Bosentan in clinical practice for treating digital and other ischemic ulcers in Spanish patients with systemic sclerosis: IBER-DU cohort study

OBJECTIVE

To describe treatment outcomes and safety experience with bosentan in patients with systemic sclerosis (SSc) and digital ulcers (DU), in a clinical setting in Spain.

METHODS

This was a multicenter, noninterventional retrospective cohort study. Data were collected retrospectively from patients with DU, with or without pulmonary arterial hypertension (PAH), who were initiating bosentan therapy in 2003 (n = 26) or 2004 (n = 41) and followed until May 2005. Data were obtained from centers prescribing bosentan. Relevant measures included number of DU, occurrence of new DU, overall DU clinical status (improved, stabilized, worsened), and bosentan-associated adverse events.

RESULTS

Sixty-seven patients with SSc and DU or other ulcers were included. PAH was also present in 12 patients (18%). At the start of bosentan treatment, the median number of DU per patient was 3.0. The median change in number of DU was -3.6 and -5.0 at 12 and 24 months, respectively. Sixty-eight percent of the patients did not develop any new DU at 12 months. DU clinical status was reported at 12 months for 22 patients: 18 patients (81.8%) improved and 4 (18.2%) stabilized. The median treatment duration was 13.0 months. The main adverse event was increase of aminotransferase, observed in 5 patients (7%), leading to discontinuation of treatment in 3 patients (4.4%).

CONCLUSION

Previously reported results of bosentan efficacy in DU management are reproducible in clinical practice. This efficacy is maintained in the longterm followup. Bosentan treatment was well tolerated and adverse events were comparable with those observed in previous reports.

Intracellular α(2C)-adrenoceptors: storage depot, stunted development or signaling domain?

G-protein coupled receptors (GPCRs) are generally considered to function as cell surface signaling structures that respond to extracellular mediators, many of which do not readily access the cell's interior. Indeed, most GPCRs are preferentially targeted to the plasma membrane. However, some receptors, including α(2C)-Adrenoceptors, challenge conventional concepts of GPCR activity by being preferentially retained and localized within intracellular organelles. This review will address the issues associated with this unusual GPCR localization and discuss whether it represents a novel sub-cellular niche for GPCR signaling, whether these receptors are being stored for rapid deployment to the cell surface, or whether they represent immature or incomplete receptor systems.

Rap1 GTPases: an emerging role in the cardiovasculature

The Ras related GTPase Rap has been implicated in multiple cellular functions. A vital role for Rap GTPase in the cardiovasculature is emerging from recent studies. These small monomeric G proteins act as molecular switches, coupling extracellular stimulation to intracellular signaling through second messengers. This member of the Ras superfamily was once described as the transformation suppressor with the ability to ameliorate the Ras transformed phenotype; however, further studies uncovered a unique set of guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs) and effector proteins for Rap suggesting a more sophisticated role for this small GTPase. At least three different second messengers can activate Rap, namely cyclic AMP (cAMP), calcium and diacylglycerol. More recently, an investigation of Rap in the cardiovasculature has revealed multiple pathways of regulation involving Rap in this system. Two closely related isoforms of Rap1 exist, 1a and 1b. Murine genetic models exist for both and have been described. Although thought at first to be functionally redundant, these isoforms have differing roles in the cardiovasculature. The activation of Rap1a and 1b in various cell types of the cardiovasculature leads to alterations in cell attachment, migration and cell junction formation. This review will focus on the role of these Rap1 GTPases in hematopoietic, endothelial, smooth muscle, and cardiac myocyte function, and conclude with their potential role in human disease.

Abnormal fibrillin-1 expression and chronic oxidative stress mediate endothelial mesenchymal transition in a murine model of systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by oxidative stress, impaired vascular function, and attenuated angiogenesis. The tight-skin (Tsk(-/+)) mouse is a model of SSc that displays many of the cellular features of the clinical disease. We tested the hypotheses that abnormal fibrillin-1 expression and chronic phospholipid oxidation occur in Tsk(-/+) mice and, furthermore, that these factors precipitate a prooxidant state, collagen-related protein expression, apoptosis, and mesenchymal transition in endothelial cells cultured on Tsk(-/+) extracellular matrix. Human umbilical vein endothelial cells were seeded on microfibrils isolated from skin of C57BL/6J (control) and Tsk(-/+) mice in the presence or absence of chronic pretreatment with the apolipoprotein Apo A-I mimetic D-4F (1 mg·kg(-1)·day(-1) ip for 6 to 8 wk). Nitric oxide-to-superoxide anion ratio was assessed 12 h after culture, and cell proliferation, apoptosis, and phenotype were studied 72 h after culture. Tsk(-/+) mice demonstrated abnormal "big fibrillin" expression (405 kDa) by Western blot analysis compared with control. Endothelial cells cultured on microfibrils prepared from Tsk(-/+) mice demonstrated reduced proliferation, a prooxidant state (reduced nitric oxide-to-superoxide anion ratio), increased apoptosis, and collagen-related protein expression associated with mesenchymal transition. Chronic D-4F pretreatment of Tsk(-/+) mice attenuated many of these adverse effects. The findings demonstrate that abnormal fibrillin-1 expression and chronic oxidative stress mediate endothelial mesenchymal transition in Tsk(-/+) mice. This mesenchymal transition may contribute to the reduction in angiogenesis that is known to occur in this model of SSc.

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.

Primary Raynaud phenomenon and small-fiber neuropathy: is there a connection? A pilot neurophysiologic study

The pathophysiologic factors of primary Raynaud phenomenon (RP) are unknown. Preliminary evidence from skin biopsy suggests small-fiber neuropathy (SFN) in primary RP. We aimed to quantitatively assess SFN in participants with primary RP. Consecutive patients with an a priori diagnosis of primary RP presenting to our outpatient rheumatology clinic over a 6-month period were invited to participate. Cases of secondary RP were excluded. All participants were required to have normal results on nailfold capillary microscopy. Assessment for SFN was accomplished with autonomic reflex screening, which includes quantitative sudomotor axonal reflex test (QSART), and cardiovagal and adrenergic function testing, thermoregulatory sweat test (TST), and quantitative sensory test (QST) for vibratory, cooling, and heat-pain sensory thresholds. Nine female participants with a median age of 38 years (range 21-46 years) and a median symptom duration of 9 years (range 5 months-31 years) were assessed. Three participants had abnormal results on QSART, indicating peripheral sudomotor autonomic dysfunction. Two participants had evidence of large-fiber involvement with heat-pain thresholds on QST. Heart rate and blood pressure responses to deep breathing, Valsalva maneuver, and 70° tilt were normal for all participants. Also, all participants had normal TST results. In total, three of the nine participants had evidence of SFN. The presence of SFN raises the possibility that a subset of patients with primary RP have an underlying, subclinical small-fiber dysfunction. These data open new avenues of research and therapeutics for this common condition.

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.

Abnormalities in the regulators of angiogenesis in patients with scleroderma

OBJECTIVE

To determine plasma levels of regulators of angiogenesis in patients with scleroderma and to correlate those levels with manifestations of scleroderma-related vascular disease.

METHODS

Plasma levels of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), fibroblast growth factor-2 (FGF-2), matrix metalloproteinase-9 (MMP-9), endostatin, pro-MMP-1, hepatocyte growth factor (HGF), placental growth factor (PlGF), and FGF-4 were examined by ELISA in a cross-sectional study of 113 patients with scleroderma and 27 healthy controls. Simple and multivariate regression models were used to look for associations between factor levels and clinical disease characteristics.

RESULTS

There were marked differences in the levels of pro-angiogenic growth factors between patients with scleroderma and controls, with significant elevations of VEGF, PDGF, FGF-2, and PlGF among patients with scleroderma (p < 0.0001). Levels of MMP were also higher in scleroderma patients compared to controls (MMP-9 and pro-MMP-1) (p < 0.0001). Levels of the pro-angiogenic and anti-fibrotic factor, HGF, were noted to be lower in patients with scleroderma, but had a positive correlation with right ventricular systolic pressure (RVSP) as measured by echocardiogram (p < 0.0001) and the Raynaud Severity Score (p = 0.05). Endostatin (an anti-angiogenic factor) was notably higher in patients with scleroderma (p < 0.0001) and also correlated positively with RVSP (p = 0.023).

CONCLUSION

These results demonstrate striking abnormalities in the circulating regulators of angiogenesis in patients with scleroderma. The levels of some factors correlate with measures of vascular disease among patients with scleroderma. Dysregulated angiogenesis may play a role in the development of scleroderma vascular disease.

The pathology of scleroderma vascular disease

Systemic sclerosis is characterized by three distinct pathologic processes: fibrosis, cellular/humoral autoimmunity, and specific vascular changes. Although a mild vasculitis may sometimes be present, the vascular pathology of scleroderma is not necessarily inflammatory and is best characterized as a vasculopathy. In this article, the authors propose that SSc vasculopathy is the result of an early event involving vascular injury that eventuates in a vicious cycle mediated in part by the immune process. The subsequent vascular malformation and rarefaction may be a function of systemic angiogenic dysregulation, with over expression of vascular endothelial growth factor but a lack of proper interactions with smooth muscle cells needed to stabilize and organize blood vessels.

Current drug therapy for scleroderma and secondary Raynaud's phenomenon: evidence-based review

(1) Scleroderma and secondary Raynaud's phenomenon are frequently associated with increased morbidity for which no specific standardised treatment guidelines exist. (2) Current therapies for scleroderma target the immune system, with the goal of reducing inflammation and secondary tissue injury and fibrosis. Therapy targeting underlying vascular disease is designed to improve the symptoms of Raynaud's phenomenon and to reduce ischemic injury to involved organs. (3) Few controlled trials of therapy used for scleroderma are completed, and current treatments are largely based on organ-specific therapy and uncontrolled case series suggesting disease modification. (4) Recent randomised, controlled trials in scleroderma demonstrate promising results in the treatment of interstitial lung disease with cyclophosphamide, and vascular disease of the lungs and digits with endothelin receptor antagonists, the phosphodiesterase inhibitor sildenafil and prostacyclins, while trials with methotrexate show only modest benefit in controlling scleroderma-associated skin disease. (5) Prostacyclins are a therapeutic option in patients with secondary Raynaud's phenomenon. Modest benefits have also been shown with alpha1-antagonists and calcium channel blockers, while the effect of ACE inhibitors has been variable. Some data suggest some benefits to the use of the phosphodiesterase inhibitor sildenafil, the serotonin uptake inhibitor fluoxetine and the angiotensin receptor inhibitor losartan.

Prevention of vascular damage in scleroderma and autoimmune Raynaud's phenomenon: a multicenter, randomized, double-blind, placebo-controlled trial of the angiotensin-converting enzyme inhibitor quinapril

OBJECTIVE

To evaluate the efficacy and tolerability of prolonged administration of quinapril, a long-acting angiotensin-converting enzyme inhibitor, in the management of the peripheral vascular manifestations of limited cutaneous systemic sclerosis (lcSSc) and in the prevention of the progression of visceral organ involvement in the disease.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled study evaluating quinapril 80 mg/day, or the maximum tolerated dosage, in 210 patients with lcSSc or with Raynaud's phenomenon (RP) and the presence of SSc-specific antinuclear antibodies. Treatment was for 2-3 years. The primary outcome measure was the number of new ischemic ulcers appearing on the hands; secondary measures were the frequency and severity of RP attacks, skin score, treatments for ischemia, health status (measured by the Short Form 36 instrument), measures of kidney and lung function, and echocardiographic estimates of pulmonary artery pressure. An intent-to-treat analysis was used.

RESULTS

Quinapril did not affect the occurrence of digital ulcers or the frequency or severity of RP episodes. It did not alter the treatments that were prescribed for either infected ulcers or severe RP symptoms. There was no apparent effect on the estimated tricuspid gradient. Health status was not affected by quinapril, and one-half of the patients who believed they had benefited from the trial treatment were in the placebo arm. Quinapril was not tolerated by one-fifth of the patients, with dry cough being the most frequent side effect.

CONCLUSION

Administration of quinapril for up to 3 years had no demonstrable effects on the occurrence of upper limb digital ulcers or on other vascular manifestations of lcSSc in this patient population.

Effects of D-4F on vasodilation, oxidative stress, angiostatin, myocardial inflammation, and angiogenic potential in tight-skin mice

Systemic sclerosis (scleroderma, SSc) is an autoimmune, connective tissue disorder that is characterized by impaired vascular function, increased oxidative stress, inflammation of internal organs, and impaired angiogenesis. Tight skin mice (Tsk−/+) have a defect in fibrillin-1, resulting in replication of many of the myocardial and vascular features seen in humans with SSc. D-4F is an apolipoprotein A-I (apoA-I) mimetic that improves vascular function in diverse diseases such as hypercholesterolemia, influenza, and sickle cell disease. Tsk−/+ mice were treated with either phosphate-buffered saline (PBS) or D-4F (1 mg·kg−1·day−1 for 6–8 wk). Acetylcholine and flow-induced vasodilation were examined in facialis arteries. Proinflammatory HDL (p-HDL) in murine and human plasma samples was determined by the cell-free assay. Angiostatin levels in murine and human plasma samples were determined by Western blot analysis. Hearts were examined for changes in angiostatin and autoantibodies against oxidized phosphotidylcholine (ox-PC). Angiogenic potential in thin sections of murine hearts was assessed by an in vitro vascular endothelial growth factor (VEGF)-induced endothelial cell (EC) tube formation assay. D-4F improved endothelium-, endothelial nitric oxide synthase-dependent, and flow-mediated vasodilation in Tsk−/+ mice. Tsk−/+ mice had higher plasma p-HDL and angiostatin levels than C57BL/6 mice, as did SSc patients compared with healthy control subjects. Tsk−/+ mice also had higher triglycerides than C57BL/6 mice. D-4F reduced p-HDL, angiostatin, and triglycerides in the plasma of Tsk−/+ mice. Tsk−/+ hearts contained notably higher levels of angiostatin and autoantibodies against ox-PC than those of control hearts. D-4F ablated angiostatin in Tsk−/+ hearts and reduced autoantibodies against ox-PC by >50% when compared with hearts from untreated Tsk−/+ mice. Angiogenic potential in Tsk−/+ hearts was increased only when the Tsk−/+ mice were treated with D-4F (1 mg·kg−1·day−1, 6–8 wk), and cultured sections of hearts from the D-4F-treated Tsk−/+ micewere incubated with D-4F (10 μg/ml, 5–7 days). Failure to treat the thin sections of hearts and Tsk−/+ mice with D-4F resulted in loss of VEGF-induced EC tube formation. D-4F improves vascular function, decreases myocardial inflammation, and restores angiogenic potential in the hearts of Tsk−/+ mice. As SSc patients have increased plasma p-HDL and angiostatin levels similar to the Tsk−/+ mice, D-4F may be effective at treating vascular complications in patients with SSc.

Cooling augments vasoconstriction mediated by 5-HT1 and alpha2-adrenoceptors in the isolated equine digital vein: involvement of Rho kinase

The vasculature of the equine digit fulfils an important role in thermoregulation. In other species, it has been found that cooling may enhance the response of cutaneous vessels to 5-hydroxytryptamine (5-HT) and alpha(2)-adrenoceptor agonists. Translocation of alpha(2)-adrenoceptors to the smooth muscle cell membrane, mediated by Rho kinase, is thought to be involved in the cooling-enhanced response in mouse tail arteries. However, little is known about the effect of cooling on 5-HT receptor function. The present investigation compared the response of 5-bromo-6-(2-imidazolin-2-ylamino) quinoxaline (UK14304:1 nM to 30 microM), methoxamine (0.1 nM to 30 microM; in the presence of yohimbine 0.1 microM), 5-carboxamidotryptamine (5-CT; 0.1 nM to 10 microM) and alpha-methyl 5-HT (0.1 nM to 10 microM) in the isolated equine digital vein at 30 degrees C and 22 degrees C. The effect of the Rho kinase inhibitor, fasudil (1 microM), and the recovery of the response after the irreversible blockade of surface receptors with phenoxybenzamine (10 microM) or 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ;10 microM), was established. Moderate cooling significantly increased the maximum response to alpha-methyl 5-HT, 5-CT and UK14304 and shifted their response curves to the left. Cooling also augmented the phenoxybenzamine- and EEDQ-resistant response to UK14304 and 5-CT, respectively. Fasudil had no effect on the contractile response at 30 degrees C, but completely abrogated the effect of cooling on the response to 5-CT and UK14304. The response to methoxamine was not significantly affected by cooling. These results suggest that Rho kinase plays an important role in the cooling-enhanced response mediated by 5-HT(1B/D) receptors and alpha(2)-adrenoceptors. The exact mechanism by which Rho/Rho kinase enhances the functional responses mediated by these receptors in these vessels has yet to be determined.

Systemic sclerosis: a prototypic multisystem fibrotic disorder

A unique feature of systemic sclerosis (SSc) that distinguishes it from other fibrotic disorders is that autoimmunity and vasculopathy characteristically precede fibrosis. Moreover, fibrosis in SSc is not restricted to a single organ, but rather affects many organs and accounts for much of the morbidity and mortality associated with this disease. Although immunomodulatory drugs have been used extensively in the treatment of SSc, no therapy to date has been able to reverse or slow the progression of tissue fibrosis or substantially modify the natural progression of the disease. In this Review, we highlight recent studies that shed light on the cellular and molecular mechanisms underlying the fibrotic process in SSc and that identify cellular processes and intra- and extracellular proteins as potential novel targets for therapy in this prototypic multisystemic fibrotic disease.

Management of vasospastic disorders with botulinum toxin A

BACKGROUND

Surgical digital artery sympathectomy is indicated when medical management has failed to control rest pain, impending infarction of digits, or healing of ischemic ulcerations caused by profound vasospasm that is associated with other systemic diseases. After digital artery sympathectomy, recurrence or persistence of vasospasm may compromise hand function and ultimately result in amputation of all or portions of both lower and upper extremities.

METHODS

The authors present a case series of 11 patients with vasospasm producing intractable rest pain, digital ulcerations, and digit infarctions that failed aggressive medical therapy and that were then treated by perivascular injections of botulinum toxin A (Botox). Before Botox injection, the level of pain, cutaneous temperatures, color, and ulcerations and infarctions were documented

RESULTS

The authors' longest follow-up was 30 months. All patients reported highly significant pain reduction, 10 of 10 to 0 to 2 of 10, within 24 to 48 hours after injection, persisting for months after the injection. Nine of 11 patients with nonhealing ulcers spontaneously healed small ulcers and areas of infarction after surgical debridement. Two cases required small skin grafts. Nine of 11 patients reported decreased severity and frequency of vasospastic episodes.

CONCLUSIONS

Hand injection of botulinum toxin A appears to be an effective treatment for intractable digital ulcerations and rest pain in patients with severe vasospastic disorders. Because of the complexity of surgical digital artery sympathectomy along with its associated high risk of persistent symptoms, the authors conclude that the therapeutic use of botulinum toxin A injections represents an attractive alternative therapy.

The Effects of Tadalafil on Cold-induced Vasoconstriction in Patients with Raynaud's Phenomenon

Raynaud's phenomenon (RP) is a disorder characterized by episodic periods of vasoconstriction typically provoked by exposure to cold. Phosphodiesterase 5 (PDE5) inhibitors may improve digital blood flow and clinical symptoms in patients with RP, but the mechanisms are unknown. We examined the hypothesis that a PDE5 inhibitor, tadalafil, attenuates cold-induced vasoconstriction. Additionally, we examined whether tadalafil reduced vascular dysfunction following ischemia, thus altering the response to repeated cooling. We conducted a double-blind, placebo-controlled crossover study in 20 subjects with RP on two separate study days, when subjects received either placebo or tadalafil (10 mg). Digital blood flow (flux) was measured by laser Doppler flowmetry at rest and during two graduated local heat and cold exposure cycles. Temperature-response curves were evaluated by E(max) (maximal flux during heating), E(min) (minimal flux during cooling), and ET(50) and ET(90) (the local temperature at which flux decreased by 50% and 90% of E(max)-E(min), respectively). Tadalafil did not increase baseline flux (81.0+/-73.0 vs 91.3+/-114.0 arbitrary unit (AU), P=0.57), E(max) (280.0+/-107.6 vs 279.5+/-119.8 AU, P=0.94), ET(50) (25.4+/-4.4 vs 26.6+/-5.7 degrees C, P=0.62), or ET(90) (21.2+/-3.9 vs 21.8+/-5.0 degrees C, P=0.78), (cycle 1 values presented). There were no differences between cycles on either study day. In conclusion, in patients with RP, single-dose tadalafil does not increase digital blood flow at baseline or in response to heating, nor does it attenuate cold-induced vasoconstriction. Furthermore, it does not precondition the endothelium to resist a second cooling challenge. The clinical benefit in patients with RP treated with PDE5 inhibitors probably involves mechanisms other than acute inhibition of cold-induced vasoconstriction.

Raynaud's phenomenon

Vascular acrosyndromes constitute a common reason for physician visits. They are associated with connective tissue disease; for example, 90% of patients with scleroderma experience Raynaud's phenomenon. The rheumatologist must strive to establish the diagnosis, to identify a potential underlying cause, and to prescribe effective treatment when the symptoms are incapacitating. Raynaud's phenomenon is the acrosyndrome most commonly encountered by rheumatologists. The diagnosis of Raynaud's phenomenon rests on clinical grounds. Nailfold capillaroscopy and immunological tests are useful chiefly for determining the cause. Calcium-channel antagonists are the treatment of reference for Raynaud's phenomenon. Drugs introduced over the last few years for severe refractory forms include prostacyclin and its derivatives, endothelin receptor antagonists, and phosphodiesterase inhibitors. These drugs were developed as a result of new knowledge on the pathogenesis of Raynaud's phenomenon. Acrocyanosis, which is extremely common, and erythromelalgia are the other main vascular acrosyndromes.

The patient with cold hands: understanding Raynaud's disease

The availability of new treatments for Raynaud's disease, as with any medical condition, depends on how convincing the results of clinical research prove to be. The validity and reliability of research in Raynaud's disease is subject to two major constraints: the seasonal and intermittent nature of the condition limits the amount of time patients can be studied continuously, and researchers have failed to agree on objective outcome measures. Vascular physiology is, and no doubt is destined to remain, a dynamic and technology-driven clinical realm. Despite the wide array of promising treatments, the best and most basic management of Raynaud's disease seems to be behavioral and at least partly pharmaceutical. The two biggest behavioral factors are nicotine use and exposure to cold environments. Giving up nicotine can be a daunting challenge for long-term smokers and chewing-tobacco users. Avoiding cold environments may be easier said than done, especially for patients who work outdoors or in air-conditioned spaces. Perhaps the best treatment for Raynaud's disease is a reliable diagnosis and the positive prognosis that comes with it. Most patients have a stable course, and nearly half will actually improve with time and steady reassurance.

[Raynaud's phenomenon]

Raynaud's phenomenon is characterized by repeated daily attacks of ischemia followed by reperfusion at the acrallevel. It is a frequent syndrome found in medical practice; and it can be considered as primary or secondary to other conditions, including rheumatic autoimmune diseases. Current classification had clinical and therapeutic implications. Careful clinical evaluation is the most reliable and reproducible method in the diagnosis of Raynaud's phenomenon. Several risk factors had been associated in the genesis of Raynaud's phenomenon; however, its pathogenesis remains elusive although recently, considerable progress in disease mechanism had been described. Such advances are directing new lines of therapy.