Understanding, assessing and treating Raynaud's phenomenon

Raynaud's Phenomenon: A Current Update on Pathogenesis, Diagnostic Workup, and Treatment

Raynaud's phenomenon (RP) is a condition characterized by episodic, excessive vasoconstriction in the fingers and toes, triggered by cold or stress. This leads to a distinctive sequence of color changes in the digits. Pallor indicates reduced blood flow due to oxygen deprivation, while erythema appears as reperfusion. RP can be primary, with no identifiable underlying cause, or secondary, associated with other conditions. These conditions include autoimmune diseases, most commonly systemic sclerosis, vascular diseases; and neurological conditions. While the exact cause of RP remains unclear, genetic and hormonal (estrogen) factors are likely contributors. The pathogenesis of RP involves a complex interaction between the vascular wall, nerves, hormones, and humoral factors, disrupting the balance between vasoconstriction and vasodilation. In primary RP, the vascular abnormalities are primarily functional. However, in secondary RP, both functional and structural components occur in blood vessels. This explains why digital tissue damage frequently occurs in secondary RP but not primary RP. Diagnosis of RP is primarily clinical. Recent advancements in imaging techniques have aided in diagnosis and monitoring, but nail fold capillaroscopy remains the gold standard for distinguishing between primary and secondary RP. If there are signs of acute ischemic injury, vascular imaging, particularly preoperatively, is crucial to rule out other vaso-occlusive conditions. Management of RP focuses on alleviating symptoms and preventing tissue damage. Vasodilator medications are the first-line treatment when general measures like warmth and stress management are not sufficient. Dihydropyridine calcium channel blockers (CCBs), such as nifedipine, are commonly used for vasodilation. Phosphodiesterase-5 inhibitors and prostaglandin analogs are alternative options for patients who do not respond to CCBs or have ischemic tissue damage. Bosentan, an endothelin-1 receptor antagonist, has shown effectiveness in treating and preventing digital ulcers, especially in patients with multiple ulcers. For severe cases, botulinum toxin injections or sympathectomy surgery can be used to control RP symptoms. However, botulinum toxin injections require repeated administration, and sympathectomy's long-term effectiveness is uncertain. Fat grafting is a promising surgical therapy for promoting healing and preventing tissue injury.

Incidence, remission, and persistence of Raynaud's phenomenon in the general population of northern Sweden: a prospective study

BACKGROUND

Raynaud's phenomenon is common condition, but little is known about the natural course. The primary aim of this study was to determine the incidence, remission, and persistence proportions of Raynaud's phenomenon in the general population of northern Sweden. Secondary aims were to determine how individual and exposure factors affect the course of Raynaud's phenomenon, and to assess gender differences.

METHODS

A prospective, survey-based, closed-cohort study was conducted on a sample of men and women between 18-70 years of age, living in northern Sweden. Data on Raynaud's phenomenon characteristics and general health status were collected during the winters of 2015 (baseline) and 2021 (follow-up). Rates of incidence, remission, and persistence were calculated. Binary logistic regression was used to determine the association between baseline variables and the course of Raynaud's phenomenon.

RESULTS

The study population consisted of 2703 women (53.9%) and 2314 men. There were 390 women (14.5%) and 290 men (12.7%) reporting Raynaud's phenomenon in the follow-up survey. The annual incidence proportion was 0.7% among women and 0.9% among men (gender difference p = 0.04). The annual remission proportion was 4.4% and 5.5%, respectively (p = 0.05). Having sustained a cold injury affecting the hands since baseline was significantly associated with incident Raynaud's phenomenon (OR 3.92; 95% CI 2.60-5.90), after adjusting for age and gender.

CONCLUSIONS

In the general population of northern Sweden, Raynaud's phenomenon is a common but variable condition, where symptoms may remit over time. Men had a higher incidence proportion than women. The results support a possible causal pathway where cold injury can precede the onset of Raynaud's phenomenon.

Long-term results of ulnar and radial reconstruction with interpositional grafting using the deep inferior epigastric artery for chronic hand ischemia

Chronic hand ischemia causes cold intolerance, intractable pain, and digital ulceration. If ischemic symptoms persist despite pharmacologic treatments, surgical interventions should be considered. This retrospective study evaluated the long-term results after ulnar and radial reconstruction using an interpositional deep inferior epigastric artery (DIEA) graft combined with periarterial sympathectomy. Patients who underwent this surgery from March 2003 to February 2019 were included. To evaluate variables influencing recurrence after the procedure, patients were divided into the recurred and non-recurred groups and their data were compared. Overall, 62 cases involving 47 patients were analyzed (16 and 46 cases in the recurred and non-recurred groups, respectively). The median DIEA graft length was 8.5 cm. The rates of rheumatic disease and female patients were significantly higher in the recurred than in the non-recurred group, without significant between-group differences in postoperative complication rates. In the multivariate analysis, underlying rheumatic disease and graft length had significant effects on recurrence. In Kaplan-Meier analysis, the 5- and 10-year symptom-free rates were 81.3% and 68.0%, respectively, with lower rates for cases with rheumatic disease. Thus, arterial reconstruction using an interpositional DIEA graft provides long-term sustainable vascular supply in patients with chronic hand ischemia, especially in those without rheumatic disease.

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.

Plexin-D1/Semaphorin 3E pathway may contribute to dysregulation of vascular tone control and defective angiogenesis in systemic sclerosis

Introduction

The vascular and nervous systems have several anatomic and molecular mechanism similarities. Emerging evidence suggests that proteins involved in transmitting axonal guidance cues, including members of class III semaphorin (Sema3) family, play a critical role in blood vessel guidance during physiological and pathological vascular development. Sema3E is a natural antiangiogenic molecule that causes filopodial retraction in endothelial cells, inhibiting cell adhesion by disrupting integrin-mediated adhesive structures. The aim of the present study was to investigate whether in systemic sclerosis (SSc) Plexin-D1/Sema3E axis could be involved in the dysregulation of vascular tone control and angiogenesis.

Methods

Sema3E levels were measured by quantitative colorimetric sandwich ELISA in serum samples from 48 SSc patients, 45 subjects with primary Raynaud's phenomenon (pRP) and 48 age-matched and sex-matched healthy controls. Immunofluorescence staining on skin sections from 14 SSc patients and 12 healthy subjects was performed to evaluate Sema3E and Plexin-D1 expression. Western blotting was used to assess Plexin-D1/Sema3E axis in human SSc and healthy dermal microvascular endothelial cells (SSc-MVECs and H-MVECs, respectively) at basal condition and after stimulation with recombinant human vascular endothelial growth factor (VEGF), SSc and healthy sera. Capillary morphogenesis on Matrigel was performed on H-MVECs treated with healthy, pRP or SSc sera in the presence of Sema3E and Plexin-D1 soluble peptides.

Results

Serum Sema3E levels were significantly higher both in pRP subjects and SSc patients than in controls. In SSc, Sema3E levels were significantly increased in patients with early nailfold videocapillaroscopy (NVC) pattern compared to active/late patterns and pRP, and in patients without digital ulcers versus those with ulcers. In SSc skin, Sema3E expression was strongly increased in the microvascular endothelium. Cultured SSc-MVECs showed higher levels of phosphorylated Plexin-D1 and Sema3E expression than H-MVECs, and stimulation with SSc sera increased phosphorylated Plexin-D1 and Sema3E in H-MVECs. The addition of Sema3E-binding Plexin-D1 soluble peptide significantly attenuated the antiangiogenic effect of SSc sera on H-MVECs.

Conclusions

Our findings suggest that Plexin-D1/Sema3E axis is triggered in SSc endothelium and may have a role in the dysregulation of angiogenesis and vascular tone control by inducing neuro-vascular mechanism alterations clinically evident in particular in the early disease phases.

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.

Efficacy of Rho kinase inhibitor fasudil in secondary Raynaud's phenomenon

OBJECTIVE

The RhoA/Rho kinase pathway plays a pivotal role in cold-induced vasoconstriction, vascular smooth muscle cells function, and vascular homeostasis. This study evaluates the efficacy of fasudil, a RhoA/Rho kinase inhibitor, to reverse cold-induced vasospasm in patients with Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc; scleroderma).

METHODS

This is a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of oral fasudil (40 mg or 80 mg) or placebo administered 2 hours before a standardized cold challenge. The fall in skin temperature after the cold challenge and time to recover 50% and 70% of prechallenge digital skin temperature were used as primary outcomes. Digital blood flow assessed by laser Doppler, time to minimum skin temperature, and rate of skin cooling were also measured.

RESULTS

A total of 17 patients with SSc and RP completed the study. After the cold challenge, skin temperatures and the average time (minutes) to recover 50% (7.9 minutes for placebo, 7.5 minutes for fasudil 40 mg, and 8.2 minutes for fasudil 80 mg; P = 0.791) and 70% (18.2 minutes for placebo, 15.0 minutes for fasudil 40 mg, and 17.1 minutes for fasudil 80 mg; P = 0.654) of prechallenge skin temperature were not significantly different across the 3 groups. The digital blood flow measurements were higher in fasudil-treated groups than placebo, but differences were not significant (P = 0.693).

CONCLUSION

Fasudil administered at a single oral dose of 40 mg or 80 mg was not associated with significant benefit in terms of the skin temperature recovery time and the digital blood flow after the cold challenge.

Vascular involvement in systemic sclerosis (scleroderma)

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

Randomized Placebo-Controlled Crossover Trial of Tadalafil in Raynaud’s Phenomenon Secondary to Systemic Sclerosis

Objective.

Raynaud’s phenomenon (RP) is an important clinical feature of systemic sclerosis (SSc) for which consistently effective therapies are lacking. The study was designed to assess the safety, tolerability, and efficacy of tadalafil, a selective, long acting type V cyclic GMP phosphodiesterase (PDE-5) inhibitor, in this clinical syndrome.

Methods.

We performed a prospective, randomized, double-blind, placebo-controlled, crossover study comparing oral tadalafil at a fixed dose of 20 mg daily for a period of 4 weeks versus placebo in women with RP secondary to SSc.

Results.

Thirty-nine subjects completed the study and were evaluable. There were no statistically significant differences in Raynaud Condition Score (RCS), frequency of RP episodes, or duration of RP episodes between treatment groups. Placebo response was a confounding factor. Tadalafil was well tolerated.

Conclusion.

Tadalafil appears to be safe and well tolerated but lacks efficacy in comparison to placebo as a treatment for RP secondary to SSc.

Prevalence of Raynaud's phenomenon in healthy Turkish medical students and hospital personnel

In this study, we investigated the frequency of Raynaud's phenomenon (RP) in medical students and hospital personnel and determined associated factors. Students and hospital personnel of our medical faculty (1,414 subjects; 838 females, 576 males, mean age, 27.2+/-6.6) were questioned for symptoms associated with RP, and the presence of smoking and headache. 530 subjects (37.5%) defined color changes on cold exposure. 51 subjects (3.6%) had biphasic or triphasic color changes (definite RP). The prevalence of definite RP in females (4.8%) was significantly higher than in males (1.9%) (P=0.005). The frequency of smoking subjects (45.1 vs. 28.8%) was significantly higher in patients with RP (P=0.009). There was numbness and/or paresthesia in 174 subjects (12.3%) who defined uniphasic color change on cold exposure (possible RP). Female sex and being a smoker were factors associated with RP in our study.

The diagnosis and treatment of Raynaud's phenomenon: a practical approach

Raynaud's phenomenon is a common disorder with vasospasm of the digital arteries causing pallor with cyanosis and/or rubor. It can be primary (idiopathic), where it is not associated with other diseases, or secondary to several diseases or conditions, including connective tissue diseases, such as scleroderma and systemic lupus erythematosus. Raynaud's is often mild enough to not require treatment; however, with secondary Raynaud's there is not only vasospasm but also fixed blood vessel defects so the ischaemia can be more severe. Complications can include digital ulcers and could, rarely, lead to amputation. Treatment is often non-pharmacological including avoiding cold and smoking cessation. Calcium channel antagonists, such as nifedipine, are often considered when treatment is needed; however, adverse effects of these drugs can include hypotension, vasodilatation, peripheral oedema and headaches. Other treatments have been studied in randomised, controlled trials including classes of drugs, such as angiotensin II inhibitors, selective serotonin reuptake inhibitors, phosphodiesterase-5 inhibitors (e.g. sildenafil), nitrates (topical or oral; the latter can be limited by adverse effects, such as flushing, headache and hypotension), and for more serious Raynaud's or its complications prostacyclin agonists may be used. There are two large studies that demonstrate that endothelin receptor blockade with bosentan can reduce the number of new digital ulcers in scleroderma patients. However, it does not affect the healing period. Thus, Raynaud's is common and often requires non-pharmacological treatment. When secondary Raynaud's is suspected, such as Raynaud's with an older age at onset or other features of connective tissue disease, then an appropriate history, physical examination and laboratory tests may be indicated to reach an appropriate diagnosis. There have been advances in pharmacological treatment, but some of the treatments are limited by adverse effects.

Sildenafil: from angina to erectile dysfunction to pulmonary hypertension and beyond

In less than 20 years, the first selective type 5 phosphodiesterase inhibitor, sildenafil, has evolved from a potential anti-angina drug to an on-demand oral treatment for erectile dysfunction (Viagra), and more recently to a new orally active treatment for pulmonary hypertension (Revatio). Here we describe the key milestones in the development of sildenafil for these diverse medical conditions, discuss the advances in science and clinical medicine that have accompanied this journey and consider possible future indications for this versatile drug.