Blood vessel anomalies seen in people with Raynaud’s syndrome (RS) are associated with abnormal levels of molecular factors that influence blood vessel activity, like constriction and dilation, a new study found.
The study, “Nailfold Capillaroscopy Assessment Of Microcirculation Abnormalities And Endothelial Dysfunction In Children With Primary Or Secondary Raynaud Syndrome,” was published in the journal Clinical Rheumatology by a team of researchers from Poland.
There are two forms of the disease, primary and secondary RS. Primary RS, the most common form, is characterized by the narrowing of blood vessels in the hands and feet for a period of time, triggered by cold temperatures or stress, causing a decrease of the blood supply to these regions and leading to cell death. These blood vessel abnormalities also exist in secondary RS, but usually accompanied by autoimmune diseases.
Researchers investigated how vessel abnormalities are influenced by molecular factors known to regulate blood vessel activity, such as endothelin-1 (ET-1), E-selectin (E-sel), interleukin-18 (IL-18), and nitrogen oxide.
To do so, 86 children with RS (between 10 and 18 years old) were included in the study, 52 with primary RS and 34 with secondary RS. The latter included children diagnosed with several other diseases, such as juvenile idiopathic arthritis (12), systemic lupus erythematosus (7), polyarteritis nodosa (3), dermatomyositis (3), mixed connective tissue disease (3), limited systemic sclerosis (3), juvenile spondyloarthropathy (1), SAPHO syndrome (1) and scleromyositis (1). A group of 29 healthy children, matched in age and gender, was also analyzed as the control group.
All children underwent a common test to evaluate blood vessels, called capillaroscopy, in which a drop of immersion oil is applied on the nail beds of the fingers. After the first analysis of local blood vessels, children were asked to immerse their non-dominant hand in cold water (16 °C, 60.8°F) for five minutes, and a second assessment of the local blood vessels was performed.
On the day of the capillaroscopy test, a blood sample was also taken to examine levels of the above-mentioned molecular factors.
Results indicated that vessel abnormalities were present in RS patients, especially those with secondary RS (52 percent for primary RS, and 76.5 percent for secondary RS), while all controls had normal capillaroscopy images.
A significant relationship was found between the presence of vessel anomalies and increased levels of the vasoconstrictor factors ET-1 and E-sel in the blood. Interestingly, both factors are present in higher levels in patients with secondary RS. According to the researchers, increased levels of ET-1 may be related with blood vessel injury, whereas E-sel levels may be connected with lasting inflammation and persistent activation or destruction of vessel cells.
The vasodilator factor nitrogen oxide was lowest in patients with primary RS, which can indicate an early phase of inflammatory connective tissue disease. Contrary to the other factors, IL-18 levels were not different between RS patients and healthy children.
“Our data indicates that [cold]-induced vasoconstrictive effects dominated in [primary] RS, whereas in [secondary] RS in the course of connective tissue diseases, it was accompanied by coexistent vasodilation due to endothelial dysfunction,” the team concluded.