Studies on tryptophan metabolism in ethylism

Area of Science:

• Biochemistry
• Nutritional Science
• Clinical Medicine

Background:

• Chronic alcoholism is associated with altered tryptophan metabolism.
• The kynurenine pathway is a major catabolic route for tryptophan.
• Metabolic dysregulation in alcoholism can impact nutrient utilization and excretion.

Purpose of the Study:

• To investigate the urinary excretion of kynurenine pathway metabolites following L-tryptophan loading in chronic alcoholics.
• To evaluate the effects of vitamin B6 and nicotinamide, alone or in combination, on tryptophan metabolism in alcoholic patients.

Main Methods:

• L-tryptophan loading test (100 mg/kg body weight) was administered to chronic alcoholic patients.
• Urinary metabolites of the kynurenine pathway were quantified.
• Patients received vitamin B6, nicotinamide, or both supplements concurrently.

Main Results:

• Alcoholic patients exhibited significantly higher urinary excretion of kynurenine metabolites (15.34%) compared to healthy controls (6.86%).
• Vitamin B6 or nicotinamide monotherapy partially reduced metabolite excretion but did not normalize the pattern.
• Combined administration of vitamin B6 and nicotinamide completely corrected the abnormal metabolite excretion in chronic alcoholics (reduced to 6.55%).

Conclusions:

• Chronic alcoholism induces a significant defect in tryptophan metabolism via the kynurenine pathway.
• Vitamin B6 and nicotinamide, when administered together, can fully restore normal tryptophan metabolite excretion in chronic alcoholics.
• This finding suggests a potential therapeutic role for combined B6 and nicotinamide in managing metabolic disturbances associated with alcoholism.