BDNF, interleukin-6, and salivary cortisol levels in depressed patients treated with desvenlafaxine

BACKGROUND

Relationships between brain-derived neurotrophic factor (BDNF), interleukin (IL)-6, and salivary cortisol and both depression severity and treatment response were assessed in patients enrolled in a double-blind, placebo-controlled trial of desvenlafaxine 50mg/d for MDD.

METHODS

Outpatients with MDD were randomly assigned to 12weeks of double-blind treatment with desvenlafaxine 50mg/d or placebo (2:1). Baseline severity was assessed using the 17-item Hamilton Rating Scale for Depression (HAM-D17); treatment response at week 12 was based on HAM-D17 total score and response and remission status. Saliva (cortisol) and blood (BDNF, IL-6) samples for biomarker assay were collected at baseline and week 12. Spearman correlations were calculated between the biomarkers at baseline, and between biomarkers and HAM-D17 total score at baseline. Logistic regression analyses were used to assess whether baseline biomarker levels predicted treatment response at week 12, with and without adjustment for baseline HAM-D17 score, treatment, and geographic region. Similarly, an analysis of covariance was used to assess whether baseline disease severity predicted biomarker change at week 12.

RESULTS

A total of 427 patients who received ≥1 dose of study drug and had baseline and ≥1 on-therapy primary efficacy evaluations were included in the analysis. At baseline, there was a statistically significant although weak correlation between levels of IL-6 and BDNF (Spearman correlation coefficient [rs]=0.120; P=0.014), but no significant correlation between baseline biomarker levels and baseline HAM-D17 total score (absolute value of all rs, ≤0.061). Desvenlafaxine 50mg/d treatment significantly reduced HAM-D17 total score from baseline at week 12 compared with placebo (P=0.006), but the three potential biomarkers did not predict treatment effects. No significant correlations were observed between the change from baseline in any biomarker level and change in HAM-D17 total score at week 12, either overall, or in desvenlafaxine or placebo groups (absolute value of all rs, 0.003-0.196). Baseline levels of BDNF, IL-6, and salivary cortisol did not significantly predict response to treatment at week 12. Although median increase in BDNF was not significantly different between desvenlafaxine (13.7%) and placebo (5.7%) groups, the increase was significantly greater (33.4% vs 4.3%; P=0.003) in patients with more severe depression at baseline (HAM-D17>22) vs those with less severe depression (HAM-D17≤22). No similar findings were observed for IL-6 or salivary cortisol.

DISCUSSION

Weak or no relationships were observed at baseline between the potential biomarkers or between biomarkers and disease severity. While baseline biomarker level did not predict treatment response, improvement in BDNF was significantly greater among patients who were more severely depressed at baseline.

Auditory cortical axons contact commissural cells throughout the guinea pig inferior colliculus

Projections from auditory cortex (AC) affect how cells in both inferior colliculi (IC) respond to acoustic stimuli. The large projection from the AC to the ipsilateral IC is usually credited with the effects in the ipsilateral IC. The circuitry underlying effects in the contralateral IC is less clear. The direct projection from the AC to the contralateral IC is relatively small. An unexplored possibility is that the large ipsilateral cortical projection contacts the substantial number of cells in the ipsilateral IC that project through the commissure to the contralateral IC. Apparent contacts between cortical boutons and commissural cells were identified in the left IC after injection of different fluorescent tracers into the left AC and the right IC. Commissural cells were labeled throughout the left IC, and many (23-34%) appeared to be contacted by cortical axons. In the central nucleus, both disc-shaped and stellate cells were contacted. Antibodies to glutamic acid decarboxylase (GAD) were used to identify GABAergic commissural cells. The majority (>86%) of labeled commissural cells were GAD-immunonegative. Despite low numbers of GAD-immunopositive commissural cells, some of these cells were contacted by cortical boutons. Nonetheless, most cortically contacted commissural cells were GAD-immunonegative (i.e., presumably glutamatergic). We conclude that auditory cortical axons contact primarily excitatory commissural cells in the ipsilateral IC that project to the contralateral IC. These corticocollicular contacts occur in each subdivision of the ipsilateral IC, suggesting involvement of commissural cells throughout the IC. This pathway - from AC to commissural cells in the ipsilateral IC - is a prime candidate for the excitatory effects of activation of the auditory cortex on responses in the contralateral IC. Overall this suggests that the auditory corticofugal pathway is integrated with midbrain commissural connections.

Is CD36 gene polymorphism in region encoding lipid-binding domain associated with early onset CAD?

CD36 is a fatty acid translocase in striated muscle cells and cardiomyocytes. Some study suggested that alterations in CD36 gene may be associated with coronary artery disease (CAD) risk. The aim of the current study was to compare the frequency of CD36 variants in region encoding lipid-binding domain in Caucasian patients with early-onset CAD, no-CAD adult controls and neonates. The study group comprised 100 patients with early onset CAD. The genetic control groups were 306 infants and 40 no-CAD adults aged over 70years. Exons 4, 5 and 6 including fragments of flanking introns were studied using the denaturing high-performance liquid chromatography technique and direct sequencing. Changes detected in analyzed fragment of CD36: IVS3-6 T/C (rs3173798), IVS4-10 G/A (rs3211892), C311T (Thr104Ile, not described so far) in exon 5, G550A (Asp184Asn, rs138897347), C572T (Pro191Leu, rs143150225), G573A (Pro191Pro, rs5956) and A591T (Thr197Thr, rs141680676) in exon 6. No significant differences in the CD36 genotype, allele and haplotype frequencies were found between the three groups. Only borderline differences (p=0.066) were found between early onset CAD patients and newborns in the frequencies of 591T allele (2.00% vs 0.50%) and CGCGCGT haplotype (2.00% vs 0.50%) with both IVS3-6C and 591T variant alleles. In conclusion, CD36 variants: rs3173798, rs3211892, rs138897347, rs5956, rs143150225 rs141680676 and C311T do not seem to be involved in the risk of early-onset CAD in Caucasian population.