Biogenic amines derived from tryptophan in systemic and cutaneous scleroderma

Area of Science:

• Biochemistry
• Dermatology
• Pharmacology

Background:

• Scleroderma is a complex autoimmune disease characterized by fibrosis and vascular abnormalities.
• Alterations in biogenic amine metabolism, particularly serotonin (5-HT) and tryptophan derivatives, have been implicated in scleroderma pathogenesis.

Purpose of the Study:

• To investigate blood serotonin (5-HT) levels and urinary excretion of 5-hydroxyindole-acetic acid (5-HIAA), tryptamine (T), and indole-acetic acid (IAA) in patients with systemic and cutaneous scleroderma.
• To explore the relationship between these biochemical markers and disease severity, vascular involvement, and prognosis.

Main Methods:

• Measurement of blood serotonin (5-HT) and urinary 5-HIAA, T, and IAA in 39 systemic scleroderma cases and 7 severe cutaneous scleroderma cases.
• Calculation of the T/IAA ratio to assess tryptophan metabolite balance.
• Correlation of biochemical findings with clinical presentation, including acrosclerosis, diffuse scleroderma, and morphea, and assessment of prognostic significance.

Main Results:

• Elevated serotonin (5-HT) with a normal T/IAA ratio was observed in systemic scleroderma with vascular involvement.
• An increased T/IAA ratio with normal serotonin was found in severe forms of scleroderma, suggesting disease progression.
• Elevated T/IAA ratio and serotonin were noted in some systemic scleroderma cases and severe generalized morphea with vascular changes.

Conclusions:

• The study suggests impaired monoamine oxidase (MAO) activity in scleroderma, leading to biogenic amine accumulation.
• An elevated T/IAA ratio appears to be a significant prognostic indicator for an adverse disease course in scleroderma.
• Biochemical profiling of serotonin and tryptophan metabolites may offer insights into scleroderma pathophysiology and progression.