Increased asymmetric dimethylarginine and endothelin 1 levels in secondary Raynaud's phenomenon: implications for vascular dysfunction and progression of disease

The role of asymmetric dimethylarginine in endothelial dysfunction and abnormal nitric oxide metabolism in systemic sclerosis: results from a pilot study

INTRODUCTION/OBJECTIVES

Systemic sclerosis (SSc) is characterized by generalized vasculopathy affecting mainly small vessels while macrovascular involvement is less investigated. The aim of this study was to examine associations between asymmetric dimethylarginine (ADMA) - a biomarker of atherosclerosis - and assessments of macrovascular endothelial function in patients with SSc.

METHODS

This was a cross-sectional study including consecutive SSc patients attending the Scleroderma Outpatient Clinic. ADMA measurement in serum samples was based on an enzyme immunoassay technique. Participants underwent blood pressure measurement according to 2018 ESC/ESH Guidelines, applanation tonometry for the evaluation of arterial stiffness, and carotid ultrasound for the measurement of the intima-media thickness (cIMT).

RESULTS

Eighty-one Caucasians (82.3% female) SSc individuals with mean age 55.44 ± 13.4 years were included in this analysis. The correlation analysis of ADMA levels (unadjusted and adjusted values) with functional and morphological parameters of atherosclerosis revealed no statistically significant associations. Subgroup analysis based on disease duration (≤ 4 years), immunologic profile (SCL-70 and ACA antibodies), disease type (limited, diffuse), and inflammatory status (erythrocyte sedimentation rate [ESR] > 25 mm/h and C-reactive protein [CRP] > 5 mg/L) showed no associations, except from a significant positive correlation between ADMA levels and cΙΜΤ_mean (r = 0.370, p = 0.044) in individuals with early SSc.

CONCLUSIONS

The results of the study suggest that ADMA may be related with accelerated atherosclerosis in early stages of the disease. However, the lack of association between other morphological and functional parameters of endothelial dysfunction may suggest that other regulators of nitric oxide metabolism may contribute to macrovascular injury in SSc in various phases of the disease. Key Points • ADMA is a biomarker of atherosclerosis and has been linked with microvascular complications of SSc. •ADMA was not correlated with morphological and functional parameters of atherosclerosis in the population of the study. •The demonstrated association between ADMA and cIMT in patients with early SSc may suggest a role of NO/ADMA pathway in the initiation of macrovascular injury in SSc.

Brachial artery flow-mediated dilation in patients with systemic sclerosis: an experience from tertiary care center from North India

Role of flow-mediated dilatation (FMD) testing in the assessment of the macrovascular dysfunction in systemic sclerosis (SS) and correlation of FMD values with disease severity. Twenty-five patients of SS and 25 healthy age-matched controls were recruited. Modified Rodnan skin thickness score (MRSS) was used for skin thickness assessment. FMD values were measured in the brachial artery. FMD values done at baseline before the initiation of treatment were lower in SSc patients (4.044 ± 2.742) compared to the healthy controls (11.076 ± 5.896) (P < 0.05). Comparison of FMD values between patients with limited cutaneous systemic sclerosis (LSSc) and diffuse cutaneous systemic sclerosis (DSSc) showed a trend toward lower in LSSc (3.182 ± 2.482) as compared to DSSc patients (5.111 ± 2.711); however, the difference was not statistically significant. Patients with lung manifestations on high-resolution CT chest showed lower FMD values (2.66 ± 2.23) compared to those without HRCT changes (6.45 ± 2.56) (P < 0.05). We demonstrate that FMD values in SSc patients were lower when compared to healthy controls. Patients with SS having pulmonary manifestations showed a lower value of FMD. Key Points • FMD is a simple non-invasive tool to assess the endothelial function in patients with systemic sclerosis. • Lower values of FMD in systemic sclerosis suggest that the endothelial dysfunction and values can also be correlated with other organ involvement such as lung and skin involvement. So, lower FMD values might be a useful marker for disease severity.

Asymmetric dimethylarginine correlates with worsening peripheral microangiopathy in systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disease characterized primarily by micro-angiopathy and endothelial dysfunction which stimulate a fibrotic process. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) inhibitor and represents a novel biomarker for vascular dysfunction. Nailfold video capillaroscopy (NVC) represents a non-invasive and reliable technique for the evaluation of microvasculopathy in SSc.

OBJECTIVES

The aim of this study was to examine the possible association between ADMA and microvascular involvement in patients with SSc.

METHODS

This was a cross-sectional study including consecutive SSc patients attending the Scleroderma Outpatient Clinic. ADMA was measured in serum samples using a commercial enzyme immunoassay. Participants underwent NVC with qualitative and semi-quantitative assessment and all NVC parameters were measured in the distal row of each finger. The findings were classified in one of the three qualitative NVC patterns: early, active, and late.

RESULTS

Eighty-one (92,6 % women) SSc individuals with mean age 55.44 ± 13.4 years were included in this analysis. Within-groups comparisons revealed a trend between higher ADMA levels and progressive micro-vasculopathy (1,29 [2,1] vs 1,57 [1,95] vs 2,41 [3,87]; for early, active and late patterns respectively, p = 0.039). Furthermore, ADMA concentration was significantly associated with the number of capillaries/mm (r = -0.235; p = 0.035).

CONCLUSIONS

Serum ADMA levels were significantly associated with advancing stages of microcirculatory abnormalities suggesting that ADMA may have a role in promoting microvascular endothelial dysfunction in SSc individuals.

The Association of Flow-Mediated Dilatation and Blood Parameters in Primary Raynaud's Phenomenon

INTRODUCTION

Raynaud's phenomenon (RP) is a multifactorial disorder. If any underlying disease cannot be determined to be responsible for RP, then it is considered to be the primary RP (pRP). We aimed to investigate the differences between laboratory markers and impaired endothelial function in pRP.

MATERIALS AND METHODS

Forty-two pRP patients and 30 healthy individuals were included as the study and control groups, respectively. The endothelial function was evaluated with flow-mediated dilatation (FMD) of the brachial artery. The blood samples were obtained from both groups, and white blood cell (WBC), hemoglobin, platelets, mean platelet volume (MPV), creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), D-dimer, fibrinogen, albumin, fibrinogen-to-albumin ratio (FAR), neutrophil-to-lymphocyte ratio (NLR), D-dimer-to-albumin ratio (DDAR), and monocyte chemoattractant protein-1 (MCP-1) parameters were studied. The blood parameters and FMD values obtained were compared between groups.

RESULTS

The groups were similar in regard to age, gender, and smoking history (p < 0.05). There was no difference between the two groups in regard to hemoglobin, platelet, MPV, creatinine, ALT, D-dimer, albumin, FAR, NLR, and DDAR levels (p < 0.05). AST levels were slightly higher in the pRP group (p=0.027). Markedly increased WBC, fibrinogen, MPV, and MCP-1 values were detected in the pRP group (p=0.001), as well as higher abnormal FMD responses (p=0.001). There was a direct correlation between abnormal FMD response and serum MCP-1 values in patients with pRP (R: 0.308, R ²: 0.095, p: 0.044).

CONCLUSION

It seems to be that MCP-1 levels are higher in patients with pRP, and increased values of MCP-1 levels seem to be related to impaired endothelial functions.

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.

Complementary therapies for patients with systemic sclerosis

Patients with systemic sclerosis often seek information regarding complementary and nutrition-based therapy. Some study results have shown that vitamins D and E, probiotics, turmeric, l-arginine, essential fatty acids, broccoli, biofeedback, and acupuncture may be beneficial in systemic sclerosis care. However, large randomized clinical trials have not been conducted. This review summarizes current data regarding various complementary therapies in systemic sclerosis and concludes with recommendations.

The clinical effects of l-arginine and asymmetric dimethylarginine: implications for treatment in secondary Raynaud's phenomenon

Secondary Raynaud's phenomenon (RP) is often the sentinel clinical finding in systemic sclerosis and may precede systemic disease by several years. Altered nitric oxide metabolism plays a critical role in both fibrosis and severe secondary RP phenotypes in these patients. Increased flux through inducible nitric oxide synthase (iNOS) drives cutaneous fibrosis. Failure of flux through endothelial nitric oxide synthase (eNOS) contributes to increased vasoconstriction and decreased vasorelaxation. The underproduction of nitric oxide by eNOS is in part due to increased levels of asymmetric dimethylarginine (ADMA), an endogenous competitive inhibitor of nitric oxide synthase. The inhibitory effects of increased ADMA levels may be counteracted increasing serum l‐arginine, which is often an effective treatment strategy in these patients. As such, l‐arginine‐based therapies should be considered in managing secondary RP, particularly given their favourable safety and tolerability profile. While there is no established dosing regimen, studies of oral l‐arginine in secondary RP suggest that divided dosing may begin at 1–2 g/day and may be titrated up to 10 g/day. Conversely, primary RP is not associated with increased ADMA production which likely accounts for the failure of l‐arginine trials to show benefit in primary RP.

A randomized, single-blinded cross-over trial of ischemic preconditioning in Raynaud's phenomenon

Introduction

Ischemic preconditioning (IPC) is protective against future ischemia, with brief cycles of ischemia and reperfusion leading to the release of circulating endogenous compounds from ischemic cells. IPC may increase vasodilatory substances and improve Raynaud's phenomenon (RP). We hypothesized that IPC would be more effective than sham in RP treatment. Sample size required 18 participants to detect 5 fewer RP attacks per week.

Methods

This was a randomized single-blinded cross-over trial. The IPC intervention of inflating a standard blood pressure cuff on the upper arm (200 mmHg) and sham intervention (60 mmHg) were performed 3 times per week for 2 weeks, with a 2-week washout period between IPC and sham interventions. Cuff inflation was performed 4 times for 2.5 minutes, with 2.5 minutes between cuff inflation. Participants completed a daily diary on RP disease activity.

Results

Eighteen participants were enrolled (17 with secondary RP and 1 with primary RP); mean age 60.8 (SD 9.4) years, 89% female; and mean number of RP attacks/2 weeks in screen was 16.9 (SD 11.3). With IPC versus sham, results were not significant including an increase of 0.5 RP episodes/week (SD: 10.0; p = 0.84), decrease of 55.6 minutes per week (SD 516.4; p = 0.66), and a decrease in average severity of 0.4 points (on a scale of 0 to 10) (SD 12.9; p = 0.88). Secondary outcomes were also not significant.

Conclusions

No significant differences in RP disease activity were found between IPC and sham. This could be due to lack of effect of IPC on RP, too few treatments, or sham having a partial effect.

Premature atherosclerosis in systemic sclerosis patients: Its relation to disease parameters and to traditional risk factors

AIM

To detect premature atherosclerosis in systemic sclerosis (SSc) patients and its relation to disease parameters and traditional risk factors.

METHOD

This study included 40 SSc patients and 40 healthy age and sex matched controls. All patients were subjected to full history taking, clinical examination, relevant laboratory and radiological investigations. Doppler ultrasonography (US) of the common carotid was performed to measure intima-media thickness (ccIMT) and Doppler US of the brachial artery was performed to measure flow mediated dilatation (FMD).

RESULTS

The mean value of ccIMT was 0.59 ± 0.2 mm in SSc patients and 0.51 ± 0.09 mm in controls and the difference was significant (P = 0.03). A statistically significant difference was found in mean brachial artery diameter before and after hyperemia, in flow change and in FMD between SSc patients and controls. ccIMT showed significant positive correlation with age, C-reactive protein (CRP), cholesterol, triglycerides and low density lipoprotein (P < 0.05). FMD showed significant positive correlation with daily dose of steroids (P = 0.04). Brachial artery diameter after hyperemia showed significant negative correlation with erythrocyte sedimentation rate (ESR). Peak systolic velocity before ischemia showed significant positive correlation with body mass index (BMI) and significant negative correlation with insulin level.

CONCLUSION

Our findings confirm the presence of premature atherosclerosis in SSc patients assessed by significant impairment of FMD, flow change and ccIMT, and it is associated with traditional cardiovascular risk factors such as age, dyslipidemia and obesity (BMI) as well as with the use of steroids and markers of inflammation such as CRP and ESR.

Difficulties in diagnosis and treatment of severe secondary Raynaud's phenomenon in a Cameroonian woman: a case report

Background

Raynaud’s phenomenon is a microvascular disorder that results in exaggerated vasoconstriction over vasodilatation secondary to an alteration in autonomic control. Though benign, it can result in severe ulceration and ultimately gangrene associated with disfiguration and permanent deformity. We present a case of severe secondary Raynaud’s phenomenon in a black-African patient from a resource-limited setting, with focus on the difficulties encountered in the diagnosis and treatment.

Case presentation

A 43-year-old female Cameroonian farmer with a 7-year history of episodic paresthesia in her fingers and toes (when exposed to cold) presented to our emergency department with severe pain, ulceration, and “darkening” of her fingertips over a period of 2 days. An examination revealed bilateral ulceration and dry gangrene of her fingers and toes, based on which a diagnosis of secondary Raynaud’s phenomenon due to a connective tissue disease was proposed. Results of paraclinical investigations were normal. Lifestyle modification along with a calcium channel blocker and phosphodiesterase type 5 inhibitor provided significant relief.

Conclusions

An early diagnosis and knowledge on appropriate treatment of Raynaud’s phenomenon is of vital importance to prevent permanent tissue damage and disability. Relying on biphasic color change for the diagnosis of Raynaud’s phenomenon in black Africans can be potentially misleading.

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.

The role of endothelial microparticles in autoimmune disease patients with Raynaud's phenomenon

BACKGROUND AND AIM

Raynaud's phenomenon (RP) is a microvascular disorder characterized by episodic peripheral vasospasm and ischemia and is commonly found in patients with autoimmune diseases (AID). The vasomotor homoeostasis and endothelial cells damage are involved in RP. Endothelial microparticles (EMPs) may act as a biomarker for endothelial damage. The aim of this study is to investigate the correlation between the levels of microparticles (MPs) and microvasculopathy in AID with RP.

METHODS

Thirty-seven patients with AID and RP (RP group) and 27 patients with AID but without RP (non-RP group) were enrolled. The microvasculopathy score of RP was graded by nailfold capillary microscopy. The plasma levels of MPs were measured by flow cytometry utilizing specific labels for endothelial MPs (CD105 and CD144) and annexin V staining for phosphatidylserine bearing-MPs (annexin V+MPs).

RESULTS

The levels of circulating EMPs (CD105+ p = 0.005, CD144+ p = 0.004), and the annexin V+ MPs (p < 0.001) were significantly elevated in the RP group compared with the non-RP group. Moreover, the high microvasculopathy scores were closely related with annexinV+ MPs levels in the RP group (p = 0.041).

CONCLUSIONS

Levels of circulating EMPs and annexin V+ MPs are elevated in AID patients with RP indicate the endothelial damage and endothelial dysfunctions. In addition, levels of annexin V+ MPs can predict the severity of microvasculopathy in AID with RP.

The association between systemic sclerosis, arginine and asymmetric dimethylarginine

Systemic sclerosis (SSc) is a kind of autoimmune disease characterized by inflammatory and endothelial dysfunction. Asymmetric dimethylarginine (ADMA), as an endogenous nitric oxide synthase inhibitor, can cause or contribute to the inflammatory syndrome and endothelial dysfunction. Recently, increased ADMA levels have been demonstrated in SSc, revealing that ADMA might play an important role for the associated manifestations of SSc. Besides, ADMA may play a significant role in the level of NO, which is produced by arginine. In the review, we discuss the role of arginine and ADMA in patients with 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.

Abnormal amplitude and kinetics of digital postocclusive reactive hyperemia in systemic sclerosis

OBJECTIVES

Postocclusive reactive hyperemia is mediated by two major mediators: sensory nerves and endothelium-derived hyperpolarizing factors. We hypothesized that the skin microvascular response to 5 min ischemia would differ depending upon the hand location in patients with systemic sclerosis (SSc), primary Raynaud's phenomenon (PRP) and healthy controls.

METHODS

Fifteen patients with SSc, 15 sex- and age-matched patients with PRP and healthy controls were enrolled. Their right hands were subjected to 5 min ischemia followed by a postocclusive hyperemia test, with local microcirculation monitoring by laser speckle contrast imaging on the dorsal face of the hand.

RESULTS

Postocclusive reactive hyperemia was abnormal in terms of peak and area under the curve (AUC) on all fingers except the thumb in patients with SSc and PRP compared with controls. In contrast, the kinetics of the response was longer only in SSc patients, with mean (SD) time to peak on the index, middle and ring finger were respectively 72 (58), 73 (51) and 67 (47) s for SSc; 40 (20), 40 (20) and 36 (19) s for PRP; and 34 (30), 34 (30) and 29 (24) s for controls (P=0.009 for interaction).

CONCLUSIONS

We observed decreased distal digital microvascular perfusion following 5 min of ischemia in patients presenting with PRP or SSc, while the kinetics was prolonged only in SSc. A dynamic assessment of digital skin blood flow using laser speckle contrast imaging following 5 min ischemia could be used as a tool to assess microvascular abnormalities in patients with Raynaud's phenomenon secondary to SSc.

Herbal Prescription, DSGOST, Prevents Cold-Induced RhoA Activation and Endothelin-1 Production in Endothelial Cells

Herbal prescription, Danggui-Sayuk-Ga-Osuyu-Saenggang-tang (DSGOST), has long been used to treat Raynaud's phenomenon (RP) in traditional Chinese medicine (TCM). However, a biological mechanism by which DSGOST ameliorates RP is yet deciphered. In this study, we demonstrate that DSGOST inhibits cold-induced activation of RhoA, in both vascular smooth muscle cells (VSMC) and endothelial cells (EC), and blocks endothelin-1-mediated paracrine path for cold response on vessels. While cold induced RhoA activity in both cell types, DSGOST pretreatment prevented cold-induced RhoA activation. DSGOST inhibition of cold-induced RhoA activation further blocked α2c-adrenoreceptor translocation to the plasma membrane in VSMC. In addition, DSGOST inhibited endothelin-1-mediated RhoA activation and α2c-adrenoreceptor translocation in VSMC. Meanwhile, DSGOST inhibited cold-induced or RhoA-dependent phosphorylation of FAK, SRC, and ERK. Consistently, DSGOST inhibited cold-induced endothelin-1 expression in EC. Therefore, DSGOST prevents cold-induced RhoA in EC and blocks endothelin-1-mediated paracrine path between EC and VSMC. In conclusion, our data suggest that DSGOST is beneficial for treating RP-like syndrome.

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.

Asymmetric dimethylarginine as a surrogate marker of endothelial dysfunction and cardiovascular risk in patients with systemic rheumatic diseases

The last few decades have witnessed an increased life expectancy of patients suffering with systemic rheumatic diseases, mainly due to improved management, advanced therapies and preventative measures. However, autoimmune disorders are associated with significantly enhanced cardiovascular morbidity and mortality not fully explained by traditional cardiovascular disease (CVD) risk factors. It has been suggested that interactions between high-grade systemic inflammation and the vasculature lead to endothelial dysfunction and atherosclerosis, which may account for the excess risk for CVD events in this population. Diminished nitric oxide synthesis—due to down regulation of endothelial nitric oxide synthase—appears to play a prominent role in the imbalance between vasoactive factors, the consequent impairment of the endothelial hemostasis and the early development of atherosclerosis. Asymmetric dimethylarginine (ADMA) is one of the most potent endogenous inhibitors of the three isoforms of nitric oxide synthase and it is a newly discovered risk factor in the setting of diseases associated with endothelial dysfunction and adverse cardiovascular events. In the context of systemic inflammatory disorders there is increasing evidence that ADMA contributes to the vascular changes and to endothelial cell abnormalities, as several studies have revealed derangement of nitric oxide/ADMA pathway in different disease subsets. In this article we discuss the role of endothelial dysfunction in patients with rheumatic diseases, with a specific focus on the nitric oxide/ADMA system and we provide an overview on the literature pertaining to ADMA as a surrogate marker of subclinical vascular disease.

Results of a Pilot Randomized Placebo-Controlled Trial in Primary and Secondary Raynaud's Phenomenon with St. John's Wort: Detecting Changes in Angiogenic Cytokines When RP Improves

Objectives.To perform a 6-week double-blind RCT in Raynaud's phenomenon (RP) comparing the plant extract St. John's Wort (SJW) to placebo. Methods. RP patients having at least 7 attacks per week were stratified by primary and secondary RP and within secondary by systemic sclerosis or other connective tissue disease. Subjects completed a daily standardized diary recording all RP attacks (frequency, duration and severity). Serum levels of 18 inflammatory and angiogenic cytokines were measured pre- and post-treatment. Results. Eighteen patients completed the study; 8 received SJW and 10 placebo. The decrease in mean number of attacks per day was 0.75 with SJW and 1.01 with placebo, P = 0.06. Attack duration and severity were not different between groups. Cytokine analyses demonstrated no between-groups differences. Combining treatment groups, those with >50% improvement in frequency of attacks yielded a significant increase in E-selectin (P = 0.049), MMP-9 (P = 0.011), G-CSF (P = 0.02), and VEGF (P = 0.012) pre- versus post-treatment. A ≥50% improvement in severity of attacks corresponded to a significant increase in levels of sVCAM-1 (P = 0.003), sICAM-1 (P = 0.007), and MCP-1 (P = 0.004). Conclusions. There were no clinical or biomarker benefit of SJW versus placebo in RP. However, combining all patients, there were changes in some cytokines that may be further investigated.

Pulmonary arterial hypertension in systemic sclerosis

Pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) is a complex clinical situation resulting from restricted flow through the pulmonary arterial circulation ending in increased pulmonary vascular resistance and right heart failure. PAH is a common and life-threatening complication in connective tissue diseases, specifically in SSc if not treated rapidly and adequately. Based on the emerging knowledge in SSc epidemiology by large scale patient cohorts such as EUSTAR, of PAH pathophysiology and advances in cardiopulmonary diagnostic techniques, several novel treatment approaches have been examined and have proceeded to licensing and daily use in the clinical practice. Amongst them are different endothelin receptor antagonists and PDE-5 inhibitors, but several other ideas are being currently pursued to improve the long-term outcome of the affected patients.

Recent achievements in the management of Raynaud's phenomenon

Raynaud's phenomenon is a clinical disorder with episodic digital ischemic vasospasm triggered by cold- or emotional-stress. It was first mentioned by Maurice Raynaud in 1862 describing "a local asphyxia of the extremities" and was further divided into primary Raynaud's disease and secondary Raynaud's phenomenon, which is often related to connective tissue diseases, but also physical or chemical strain. Though pathophysiology of Raynaud's phenomenon is still poorly understood, systemic and local vascular effects are most likely to be involved in primary Raynaud's disease. In secondary Raynaud's phenomenon additional abnormalities in vascular structure and function may play the major role. Thus, medical treatment of Raynaud's phenomenon remains unsatisfactory, due to limited understanding of pathophysiological mechanisms. This review addresses current evidence for medical treatment of primary and secondary Raynaud's phenomenon with regard to pathophysiological mechanisms as well as future perspectives.

Correlation of Biomarkers of Endothelium Dysfunction and Matrix Remodeling in Patients with Systemic Sclerosis

Objective.

Systemic sclerosis (SSc) is a multisystem disease characterized by microvascular dysfunction and excessive fibrosis. However, the relationship between these 2 features remains unclear. Endothelial dysfunction can be assessed by quantifying plasma asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide synthase. Matrix remodeling can be assessed by quantifying serum tissue inhibitor of matrix metalloproteinases-1 (TIMP-1). Both biomarkers are elevated in patients with SSc. Our objective was to test whether plasma ADMA is correlated with serum TIMP-1.

Methods.

We enrolled 91 subjects, 39 patients with SSc, 28 patients with primary Raynaud’s phenomenon (RP), and 24 healthy volunteers. Plasma ADMA concentrations were measured by liquid chromatography-tandem mass spectrometry. Serum TIMP-1 concentrations were determined by ELISA.

Results.

Mean ADMA concentrations were higher in patients with SSc (0.68 μM ± 0.12) than in patients with primary RP or healthy volunteers (respectively, 0.56 μM ± 0.14 and 0.62 μM ± 0.12; p = 0.002). Median serum TIMP-1 concentrations were increased in patients with SSc compared to primary RP and healthy volunteers [12 (9–15), 11 (8–13), and 10 (7–13) nM, respectively; p = 0.05]. In the SSc group, we observed a statistically significant correlation between plasma ADMA and serum TIMP-1 (r = 0.34, p = 0.035).

Conclusion.

These data are consistent with our hypothesis of an association of endothelial dysfunction and matrix remodeling in scleroderma spectrum disorders.

[Primary and secondary Raynaud's phenomenon]

The term Raynaud's phenomenon describes an abnormal vasospastic response to cold or emotional stress. It is a common condition with a prevalence of 3-5% of the population. Clinically, Raynaud's phenomenon manifests as sharply demarcated colour changes of the skin of the digits that is often accompanied by paraesthesia. Raynaud's phenomenon can be subdivided into primary, or idiopathic, and secondary forms, in the latter of which associated diseases or causes can be identified. The pathogenesis of the disease is incompletely understood. Pathologic changes have been observed primarily in vascular smooth muscle cells, endothelial cells and perineuronal microvasculature. Current therapeutic strategies include supportive treatments, topical therapeutic approaches and systemic medication. Drug therapies with proven efficacy include calcium channel blockers, prostacyclin analogues, fluoxetine, losartan and sildenafil.

Microvascular responses following digital thermal hyperaemia and iontophoresis measured by laser Doppler imaging in idiopathic inflammatory myopathy

OBJECTIVE

To measure microvascular function using laser Doppler imaging following digital hyperaemia and iontophoresis of vasoactive substances in patients with idiopathic inflammatory myopathy (IIM).

METHODS

Fifteen patients with IIM including eight patients with dermatomyositis (DM) and seven patients with polymyositis (PM) were studied. Fifteen age-matched normal controls were also recruited. Scanning red laser Doppler imaging (LDI) was performed after resting the subject in a temperature controlled room at 23 degrees C for 20 min. An initial LDI scan was performed to assess baseline blood flow. Digital microvascular responses were quantified following a maximum hyperaemic response (MHR) and iontophoresis with endothelial dependent acetylcholine (Ach) and endothelial independent sodium nitroprusside (SNP). Maximum vasodilation following iontophoresis was expressed as a percentage of the MHR.

RESULTS

All subjects were age matched, and the duration of disease was similar between the IIM patients. There was no significant difference in baseline blood flow when comparing the three study groups. There was no significant difference in MHR or SNP/MHR when comparing DM or PM with controls. However, Ach/MHR was significantly lower in both the DM and PM group compared with controls (both P < 0.01). There was no significant difference in any of the microvascular responses when comparing patients with DM directly with PM.

CONCLUSION

This is the first study to evaluate microvascular responses using LDI in patients with IIM. We have demonstrated that patients with DM have abnormal endothelial dependent mediated vasodilation and the same abnormality is present in patients with PM.

Raynaud-Phänomen in der Dermatologie

Raynaud phenomenon (RP) is characterized by recurrent spasms of small digital arterioles/arteries at fingers and toes, usually triggered by cold and emotional stress. Clinically a sudden pallor of individual digits is followed by reactive hyperemia, in severe cases also by cyanosis. One distinguishes between primary RP, i.e. RP without an underlying disease or drug intake, and secondary RP, which is causally related to an underlying disease or to intake of certain drugs (e.g. interferon, cisplatin). Primary RP is frequent (prevalence of about 13-20% in northern or central Europe), while secondary RP is rare, but the major presenting symptom for systemic sclerosis (SSc). Differential diagnosis includes cold-induced pallor, acute embolic events, paroxysmal hematoma of the finger or erythromelalgia. Vasoconstrictive mechanisms outweigh vasodilatory ones in endothelial cells and vascular smooth muscle. Although soluble mediators such as endothelin or certain prostaglandins have been exploited successfully for therapy, the extent of their involvement in the initial pathophysiology of RP is unclear. Secondary RP (associated with SSc) additionally features morphological alterations with compromise of the vessel lumen. As RP can result in severe discomfort and complications, timely diagnosis and treatment is essential.

Digital thermal hyperaemia impairment does not relate to skin fibrosis or macrovascular disease in systemic sclerosis

OBJECTIVES

Thermal hyperaemia is impaired in patients with systemic sclerosis (SSc). The objective of these studies was to determine whether this was consecutive to skin fibrosis, microangiopathy or macroangiopathy.

METHODS

Using laser Doppler flowmetry, we first compared the thermal hyperaemia on the third left finger pad and on the left forearm in 21 patients with non-diffuse systemic sclerosis (SSc), in comparison with primary Raynaud's phenomenon and healthy volunteers. Second, we tested whether the altered thermal hyperaemia correlated to the digital pressure index at baseline, and following the thermal challenge.

RESULTS

In the first study, thermal hyperaemia of the finger pad was impaired in terms of both amplitude and kinetics, but not on the forearm in patients with SSc. In the seven SSc patients without cutaneous fibrosis, the response was similarly altered in terms of amplitude and kinetics. In the second study, we observed a weak correlation between the digital systolic blood pressure index. However, in the 15 SSc patients tested at 44 degrees C, the median digital systolic blood pressure index was 1.04 (0.84-1.24) at baseline vs 1.08 (0.87-1.29) at 44 degrees C (NS), while seven of them had an abnormal response in terms of kinetic. Furthermore, only one patient showed a clear-cut decrease in digital systolic blood pressure at 44 degrees C.

CONCLUSION

In patients with SSc, digital thermal hyperaemia is impaired, but does not relate to the skin fibrosis or to an associated macroangiopathy in most cases. Further studies are required to determine whether its impairment reflects a functional or structural microvascular damage.

Postocclusive reactive hyperemia inversely correlates with urinary 15-F2t-isoprostane levels in systemic sclerosis

Microvascular dysfunction and increased oxidative stress are major hallmarks of the systemic sclerosis disease process. The primary objective of this study was to test whether there is a link between peak postocclusive hyperemia and urinary levels of the F2-isoprostane 15-F2t-IsoP (8-iso-PGF2alpha) in patients suffering from systemic sclerosis. We enrolled 43 patients suffering from systemic sclerosis, 33 patients with primary Raynaud's phenomenon (RP), and 25 healthy volunteers. Microvascular function was assessed using the postocclusive hyperemia monitored by laser Doppler flowmetry. Endothelium-independent response was monitored after 0.4 mg sublingual nitroglycerin. Oxidative stress status was assessed by urinary levels of the F2-isoprostane 15-F2t-IsoP using GC-MS. The peak postocclusive vascular conductance was altered in subjects with systemic sclerosis and primary RP compared to controls (respectively 28 (7-48), 30 (13-48), and 39.9 (13-63) mV/mm Hg, p = 0.01). F2-isoprostanes were increased in the systemic sclerosis group compared to primary Raynaud's phenomenon and healthy controls (respectively 230 (155-387), 182 (101-284), and 207 (109-291) pg/mg, p = 0.006). In patients suffering from systemic sclerosis, there was a significant inverse correlation between F2-isoprostanes and postocclusive hyperemia, expressed as raw data (R = -0.45, p = 0.007) or as an increase over baseline (R = -0.28, p = 0.04). Conversely, no correlation was found with the nitroglycerin response. In conclusion, we provide evidence that there is an inverse correlation between postocclusive hyperemia and urinary F2-isoprostane levels in patients suffering from systemic sclerosis. Whether oxygen free radicals initiate the vascular dysfunction or whether there is an initial trigger that initiates both processes will need to be further clarified in future studies.

Abnormal nitric oxide metabolism in systemic sclerosis: increased levels of nitrated proteins and asymmetric dimethylarginine

OBJECTIVES

Endothelial dysfunction is a primary event in systemic sclerosis; however, the aetiology of events and the role of nitric oxide (NO) is still unclear. The aim of the present study is to investigate whether there are abnormalities in NO metabolism in plasma from patients with primary Raynaud's phenomenon (RP) and in the pathogenesis of systemic sclerosis (SSc): limited SSc (lSSc) and diffuse (dSSc). We also wanted to investigate the effect of factors within patients' SSc serum on NO metabolism in human microvascular endothelial cells (HMECs).

METHODS

Plasma (n=89) or serum (n=80) was assayed for total nitrate and nitrite (NOx), nitration of proteins and the NO inhibitor asymmetric dimethylarginine (ADMA). HMECs were treated with patients' SSc serum and assayed for indicators of NO metabolism.

RESULTS

Plasma NOx was elevated in patients with RP or lSSc (P<0.002), but not in patients with dSSc, compared with controls. Nitrated proteins in plasma, however, were found to be very high in dSSc patients (P<0.03), compared with RP, lSSc or controls. Patients with dSSc also showed increased levels of serum ADMA (P<0.05). The high level of nitrated proteins in dSSc was strongly associated with the severity and duration of dSSc disease. Skin biopsy sections from dSSc patients also showed enhanced nitrotyrosine staining compared with controls. In HMECs, pre-incubation with SSc serum impaired the activity of nitric oxide synthase (NOS) but not the expression of inducible or endothelial NOS. SSc serum also induced a reduction in intracellular cGMP synthesis, and NOx production in the cell culture medium, but was not associated with increased cell cytotoxicity.

CONCLUSIONS

NO formation is increased in patients with primary RP or lSSc, but nitration of proteins and elevated ADMA is a particular feature of dSSc and may reflect abnormal NO regulation and/or contribute to endothelial dysfunction in SSc.

Local hyperemia to heating is impaired in secondary Raynaud's phenomenon

Accurate and sensitive measurement techniques are a key issue in the quantification of the microvascular and endothelial dysfunction in systemic sclerosis (SSc). Thermal hyperhemia comprises two separate mechanisms: an initial peak that is axon reflex mediated; and a sustained plateau phase that is nitric oxide dependent. The main objective of our study was to test whether thermal hyperhemia in patients with SSc differed from that in patients with primary Raynaud's phenomenon (RP) and healthy controls. In a first study, we enrolled 20 patients suffering from SSc, 20 patients with primary RP and 20 healthy volunteers. All subjects were in a fasting state. Post-occlusive hyperhemia, 0.4 mg sublingual nitroglycerin challenge and thermal hyperhemia were performed using laser Doppler flowmetry on the distal pad of the third left finger. In a second study, thermal hyperhemia was performed in 10 patients with rheumatoid arthritis and 10 patients with primary RP. The thermal hyperhemia was dramatically altered in terms of amplitude and kinetics in patients with SSc. Whereas 19 healthy volunteers and 18 patients with primary RP exhibited the classic response, including an initial peak within the first 10 minutes followed by a nadir and a second peak, this occurred only in four of the SSc patients (p < 0.0001). The 10 minutes thermal peak was 43.4 (23.2 to 63), 42.6 (31 to 80.7) and 27 (14.7 to 51.4) mV/mm Hg in the healthy volunteers, primary RP and SSc groups, respectively (p = 0.01), while the 44°C thermal peak was 43.1 (21.3 to 62.1), 42.6 (31.6 to 74.3) and 25.4 (15 to 52.4) mV/mm Hg, respectively (p = 0.01). Thermal hyperhemia was more sensitive and specific than post-occlusive hyperhemia for differentiating SSc from primary RP. In patients with rheumatoid arthritis, thermal hyperhemia was also altered in terms of amplitude. Thermal hyperhemia is dramatically altered in patients with secondary RP in comparison with subjects with primary RP. Further studies are required to determine the mechanisms of this altered response, and whether it may provide additional information in a clinical setting.

Pathogenesis of Raynaud's phenomenon

The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

Asymmetric dimethylarginine (ADMA): the silent transition from an 'uraemic toxin' to a global cardiovascular risk molecule

Endothelial dysfunction as a result of reduced bioavailability of nitric oxide (NO) plays a central role in the process of atherosclerotic vascular disease. In endothelial cells NO is synthesized from the amino acid l-arginine by the action of the NO synthase (NOS), which can be blocked by endogenous inhibitors such as asymmetric dimethylarginine (ADMA). Acute systemic administration of ADMA to healthy subjects significantly reduces NO generation, and causes an increase in systemic vascular resistance and blood pressure. Increased plasma ADMA levels as a result of reduced renal excretion have been associated with atherosclerotic complications in patients with terminal renal failure. However, a significant relationship between ADMA and traditional cardiovascular risk factors such as advanced age, high blood pressure and serum LDL-cholesterol, has been documented even in individuals without manifest renal dysfunction. As a consequence, the metabolism of ADMA by the enzyme dimethylarginine dimethylaminohydrolase (DDAH) has come into the focus of cardiovascular research. It has been proposed that dysregulation of DDAH with consecutive increase in plasma ADMA concentration and chronic NOS inhibition is a common pathophysiological pathway in numerous clinical conditions. Thus, ADMA has emerged as a potential mediator of atherosclerotic complications in patients with coronary heart disease, peripheral vascular disease, stroke, etc., being the culprit and not only an innocent biochemical marker of the atherosclerotic disease process.

The myth of pulmonary Raynaud's phenomenon: the contribution of pulmonary arterial vasospasm in patients with systemic sclerosis related pulmonary arterial hypertension

OBJECTIVE

To investigate the contribution of cold induced pulmonary vasospasm by peripheral and central cold stimulus in exacerbating pulmonary arterial hypertension (PAH) in patients with systemic sclerosis undergoing cardiac catheterisation.

METHODS

In a prospective pilot study, 21 patients with systemic sclerosis and catheter proven PAH had mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac output (CO) measured before and after peripheral (hand immersion into cold water at 10-15 degrees C for two minutes if tolerated) and central (direct cold water at 4 degrees C injected into the right atrium) cold pressor challenge. Markers of endothelial activation, platelet function, and nitric oxide degradation were measured in blood sampled from the pulmonary artery.

RESULTS

19 of the patients (mean (SD) age, 56 (4) years; baseline mPAP, 34 (8) mm Hg; PVR, 420 (87) dyne.s.cm(-5); CO, 6.4 (1.8) l/min) tolerated cold hand immersion for the maximum two minute duration. All 21 tolerated central cold pressor challenge (three to five injections of 10 ml saline boluses at 4 degrees C). There was no significant change in haemodynamics after cold challenge by either route of provocation. Levels of endothelin-1, von Willebrand factor, fibrinogen, and 3-nitrotyrosine were raised compared with control values in patients with systemic sclerosis but without PAH, but did not change significantly after peripheral cold challenge.

CONCLUSIONS

Pulmonary vasospasm in response to peripheral and centrally administered cold pressor challenge is unlikely to contribute to persistence of pulmonary arterial hypertension in patients with systemic sclerosis.

PRMT7, a new protein arginine methyltransferase that synthesizes symmetric dimethylarginine

The cDNA for PRMT7, a recently discovered human protein-arginine methyltransferase (PRMT), was cloned and expressed in Escherichia coli and mammalian cells. Immunopurified PRMT7 actively methylated histones, myelin basic protein, a fragment of human fibrillarin (GAR) and spliceosomal protein SmB. Amino acid analysis showed that the modifications produced were predominantly monomethylarginine and symmetric dimethylarginine (SDMA). Examination of PRMT7 expressed in E. coli demonstrated that peptides corresponding to sequences contained in histone H4, myelin basic protein, and SmD3 were methylated. Furthermore, analysis of the methylated proteins showed that symmetric dimethylarginine and relatively small amounts of monomethylarginine and asymmetric dimethylarginine were produced. SDMA was also formed when a GRG tripeptide was methylated by PRMT7, indicating that a GRG motif is by itself sufficient for symmetric dimethylation to occur. Symmetric dimethylation is reduced dramatically compared with monomethylation as the concentration of the substrate is increased. The data demonstrate that PRMT7 (like PRMT5) is a Type II methyltransferase capable of producing SDMA modifications in proteins.