Age‐related changes in BDNF protein levels in human serum: differences between autism cases and normal controls

Abstract

Accumulating evidence suggests the possible association between the concentrations of serum brain-derived neurotrophic factor (BDNF) and psychiatric disease with impaired brain development. Yet the reasons remain unclear. We therefore investigated the characteristics of serum BDNF as well as its age-related changes in healthy controls in comparison to autism cases. BDNF was gradually released from platelets at 4 degrees C, reached a maximal concentration after around 24 h, and remained stable until 42 h. At room temperature, BDNF was found to be immediately degraded. Circadian changes, but not seasonal changes, were found in serum levels of BDNF existing as the mature form with a molecular mass of 14 kDa. In healthy controls, the serum BDNF concentration increased over the first several years, then slightly decreased after reaching the adult level. There were no sex differences between males and females. In the autism cases, mean levels were significantly lower in children 0-9 years old compared to teenagers or adults, or to age-matched healthy controls, indicating a delayed BDNF increase with development. In a separate study of adult rats, a circadian change in serum BDNF was found to be similar to that in the cortex, indicating a possible association with cortical functions.

Autism spectrum disorders: neurotrophins enter the dance

“…Although this observation is in harmony with results from other studies showing high concentrations of BDNF in autistic children (26), in another study the opposite result is reported (27). The level of serum BDNF was investigated as well as its age-related changes in healthy controls in comparison to autistic subjects.…”

“…It has been noted that there were not any age-related changes in the serum levels of BDNF as in other studies (27). In a population of Chinese children aged around 4 years the potential role of BDNF was explored (29).…”

“…Furthermore, circadian and/or seasonal and sex dependent changes in the level of BDNF is recognized in some studies (27,(32)(33)(34).…”

Brain‐derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) study

“…The antibodies used for capture and detection in the various assays may recognize different forms of the BDNF molecule and differences in dilution factors or developmental age of subjects at specimen collection are likely to influence results [Katoh-Semba et al, 2007;Nelson et al, 2006]. The Luminex bead-based assay used for BDNF determinations in our study is highly sensitive (o10 pg/mL), and serum levels in maternal mid-pregnancy specimens were similar to those reported previously [Lommatzsch et al, 2006], whereas the standard ELISA assay only measures down to the ng/mL range.…”

Immune System and Neurotrophic Factors in Autism

“…In the autism cases, mean levels were significantly lower in children between 0-9 ages compared to teenagers or adults, or to age-matched healthy controls, indicating a delayed BDNF increase with development. In the same study, circadian changes, but not seasonal changes, were found in serum levels of BDNF (Katoh-Semba et al 2007). There is a little number of studies that concentrated on CSF levels of neurotrophic factors.…”