Analysis of Peripheral Serotonin Levels in a Control Cohort

Serotonin (5-HT or 5-hydroxytryptamine) is a monoamine primarily recognized for its role as a neurotransmitter in the central nervous system (CNS). It is synthesized from tryptophan, which is also essential for the production of metabolites in the kynurenine and indole families.

However, serotonin's functions extend beyond the CNS: various peripheral tissues have the capacity to produce and/or utilize serotonin locally, forming systems referred to as "micro-serotonergic." Among serotonin's peripheral roles, it has been demonstrated to positively influence erythropoiesis and red blood cell survival, iron metabolism, skin pigmentation, as well as placental and embryonic development during pregnancy.

In humans, there is no established standard for blood serotonin levels. It is known that, aside from major events, an individual's serotonin levels remain stable throughout life, but it is likely that blood serotonin levels depend on age and sex.

We aim to establish a cohort of adult control patients, for whom we will measure serum serotonin and the different metabolites of tryptophan, to analyze whether serotonin varies according to sex and age, and to determine its average serum levels.

Preliminary data from the laboratory suggest a role for serotonin in iron metabolism. Therefore, as a secondary objective, we also intend to perform an iron status assessment in control patients to analyze whether there are variations in iron parameters based on serotonin levels.

This cohort could also serve as a comparison point for future studies of serum serotonin levels in pathological conditions or during pregnancy.

Inclusion criteria

• Adult patients aged ≥ 18 years
• Who have undergone a blood draw at CHSF during the recruitment period
• With hemoglobin, white blood cell, and platelet counts within the laboratory's normal ranges
• With a C-reactive protein (CRP) level < 30 mg/L

Exclusion criteria

• Patients informed about the study who decline participation
• Patients with a current diagnosis or history of psychiatric disorders
• Patients on antidepressants or narcotics at the time of sampling