Decreased plasma concentrations of brain-derived neurotrophic factor (BDNF) in patients with functional hypothalamic amenorrhea

8632 Background: Increased proinflammatory cytokines (IL-6) and decreased brain-derived neurotrophic factor (BDNF) levels have been implicated in the pathophysiology of depression. Depression has been shown to be associated with cognitive dysfunction. The objective of this study was to assess the correlations between cognitive dysfunction, IL-6 and BDNF in cancer patients (pts) with depression. Methods: Depression was assessed in 55 patients with metastatic cancer by the Hospital Anxiety and Depression Scale (HADS) and diagnosis was established according to DSM-IV criteria. Cognitive function was assessed by the Auditory Verbal Learning Test (AVLT). Plasma concentrations of Interleukin-6 and BDNF were measured at 8 AM the same day. In the statistical analysis the Mann-Whitney test and the Pearson correlation were applied. Results: Pts characteristics (n=55): median age 60 y (25–85); 76.9% Females, 23.1% males. 52% of pts had depression. There were no significant differences in mean age or Karnofsky-index between pts with and without depression. Depression was associated with a significant higher median IL-6 level (14.8 vs. 3.7 pg/ml; p<0,001). For Cognitive function only the longterm memory was significantly reduced in depression (p=0.01). However, there was no difference in BDNF levels between both groups (p=0.164). There were correlations between HADS-D score and IL6 (r=4.11; p=0.002), IL-6 and BDNF (r= −0.42; p=0.001), BDNF and longterm memory (r=0.48; p=0.02). No correlations were found for level of depression (HADS-D score) and BDNF levels (r= −0.20; P=0.14). Conclusions: Depression and increased plasma IL-6 concentrations are strongly associated in pts with cancer. There seems to be no association between BDNF and depression in cancer pts. However there is a positive correlation between the cognitive function, at least for longterm memory, with BDNF. No significant financial relationships to disclose.

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Factors affecting stability of plasma brain-derived neurotrophic factor

Scientific Reports ◽

10.1038/s41598-020-77046-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Jocelyn M. Wessels ◽

Ravi K. Agarwal ◽

Aamer Somani ◽

Chris P. Verschoor ◽

Sanjay K. Agarwal ◽

...

Keyword(s):

Neurotrophic Factor ◽

Storage Time ◽

Storage Temperature ◽

Plasma Concentrations ◽

Brain Derived Neurotrophic Factor ◽

Plasma Samples ◽

Factors Affecting ◽

Freeze Thaw ◽

Gynecological Disorders ◽

Acceptable Range

AbstractCirculating concentrations of brain-derived neurotrophic factor (BDNF) have been linked to cancer, neuropsychiatric, diabetes, and gynecological disorders. However, factors influencing plasma storage and subsequent BDNF quantification are incompletely understood. Therefore, the anticoagulant used in plasma separator tubes, storage-time, storage-temperature, and repeated freeze–thaw cycles on circulating BDNF concentrations was evaluated. Peripheral blood samples were collected from healthy women (n = 14) and men (n = 10) recruited prospectively from McMaster University (August 2014). Blood was collected from the cubital vein into plasma separator tubes containing five different anticoagulant systems [K2EDTA, Li-Hep, Li-Hep (gel), Na-Hep, Na-Hep (glass)], and placed on ice for transport to the lab for centrifugation. Plasma samples (n = 16) collected in K2EDTA tubes from women recruited to a previous study (April 2011 to December 2012) were used to determine the effect of multiple freeze–thaw cycles. Plasma BDNF was quantified using a commercially available ELISA kit. Plasma concentrations of BDNF were significantly affected by the type of plasma separator tube, storage-time, and number of freeze–thaw cycles. Storage temperature (− 20 vs. − 80 °C) did not significantly affect the quantity of BDNF measured as mean BDNF concentrations generally fell within our calculated acceptable change limit up to 6 months in the freezer. Our results suggest that for quantification of circulating BDNF blood collected in K2EDTA tubes and plasma stored up to 6 months at either − 20 or − 80 °C produces reproducible results that fall within an acceptable range. However, plasma samples stored beyond 6 months and repeated freeze–thaw cycles should be avoided.

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