Maximum blood flow and microvascular regulatory responses in systemic sclerosis

Area of Science:

• Vascular Biology
• Rheumatology
• Medical Imaging

Background:

• Systemic sclerosis (SSc) is a complex autoimmune disease characterized by microvascular dysfunction.
• Primary Raynaud's phenomenon (PRP) shares some vascular symptoms with SSc, necessitating differentiation.
• Laser Doppler imaging (LDI) offers a non-invasive method to assess microvascular reactivity.

Purpose of the Study:

• To compare microvascular responses to hyperaemia, neurovascular reflex, and iontophoresis in SSc, PRP, and controls.
• To investigate the relationship between Medsger vascular score and endothelial function in SSc patients.
• To evaluate endothelial-dependent and independent vascular responses using LDI.

Main Methods:

• Utilized laser Doppler imaging (LDI) to assess digital microvascular function in 20 SSc patients, 10 PRP patients, and 17 controls.
• Quantified responses to maximum hyperaemic response (MHR), contralateral vasoconstrictor response (CLVc), and iontophoresis (acetylcholine and sodium nitroprusside).
• Assessed SSc patients using the Medsger vascular severity scale.

Main Results:

• SSc patients showed significantly lower MHR and CLVc compared to controls and PRP.
• Endothelial-dependent responses (Ach/MHR) were reduced in SSc compared to both PRP and controls.
• Higher Medsger vascular scores in SSc correlated with diminished endothelial-dependent and independent responses.

Conclusions:

• Systemic sclerosis patients demonstrate abnormal microvascular regulatory responses.
• The degree of endothelial dysfunction in SSc appears linked to the extent of peripheral vascular involvement.
• LDI is a valuable tool for characterizing microvascular abnormalities in SSc and differentiating from PRP.