Influence of endogenous and exogenous sex hormones on plasma brain-derived neurotrophic factor

The interaction of BDNF with estrogen in the development of hypertension and obesity, particularly during menopause

The expression of BDNF in both neuronal and non-neuronal cells is influenced by various stimuli, including prenatal developmental factors and postnatal conditions such as estrogens, dietary habits, and lifestyle factors like obesity, blood pressure, and aging. Central BDNF plays a crucial role in modulating how target tissues respond to these stimuli, influencing the pathogenesis of hypertension, mitigating obesity, and protecting neurons from aging. Thus, BDNF serves as a dynamic mediator of environmental influences, reflecting an individual's unique history of exposure. Estrogens, on the other hand, regulate various processes to maintain overall physiological well-being. Through nuclear estrogen receptors (ERα, ERβ) and the membrane estrogen receptor (GPER1), estrogens modulate transcriptional processes and signaling events that regulate the expression of target genes, such as ERα, components of the renin-angiotensin system (RAS), and hormone-sensitive lipase. Estrogens are instrumental in maintaining the set point for blood pressure and energy balance. BDNF and estrogens work cooperatively to prevent obesity by favoring lipolysis, and counteractively regulate blood pressure to adapt to the environment. Estrogen deficiency leads to menopause in women with low central BDNF level. This review delves into the complex mechanisms involving BDNF and estrogen, especially in the context of hypertension and obesity, particularly among postmenopausal women. The insights gained aim to inform the development of comprehensive therapeutic strategies for these prevalent syndromes affecting approximately 68% of adults.

Plasma Brain-Derived Neurotrophic Factor (BDNF) Levels and BDNF Promoters' DNA Methylation in Workers Exposed to Occupational Stress and Suffering from Psychiatric Disorders

INTRODUCTION

Decreased plasma BDNF (pBDNF) levels have been proposed as a biomarker in the illness phases of mood disorders. This cross-sectional study aimed to evaluate the pBDNF and BDNF promoters' DNA methylation levels in workers exposed to occupational stress and suffering from work-related stress disorders.

METHODS

the pBDNF and BDNF exon I and IV promoters' methylation levels were measured by specific immunoassays and methylation-sensitive high-resolution melting (MS-HRM) in 62 patients with adjustment disorders (AD), 79 patients with major depressive disorder (MDD) and 44 healthy controls. Occupational stress was evaluated in the patients and controls using the Job Content Questionnaire (JCQ).

RESULTS

the pBDNF levels were significantly higher in the MDD (p < 0.001) and AD (p < 0.0001) patients than in the controls. The MDD patients showed significantly lower pBDNF levels than the AD ones (p = 0.01). The BDNF exon I and IV promoters' methylation levels were significantly higher in the MDD patients than in the AD ones (exon I promoter: p = 0.0001, exon IV promoter: p < 0.0001) and controls (exon I promoter: p = 0.0001, exon IV promoter: p < 0.0001). In the patients, but not in the controls, the BDNF promoters' methylation levels showed significant negative correlations with occupational stress.

CONCLUSIONS

BDNF could play a key role in the pathophysiology of stress-related disorders and the peripheral elevation of it observed in patients exposed to occupational stress could suggest a protective mechanism for neurons from stress-mediated damage. The elevation of the pBDNF levels, even in MDD, may characterize a "reactive" subtype of depressive episode, while the significant elevation of the BDNF promoters' methylation levels in depressed patients could indicate a predisposition to more severe illness under stress. Further research is needed, focusing on biomarkers for stress-related disorders as a potential tool for the diagnosis and prevention of occupational diseases.

The effect of antidepressant treatment on blood BDNF levels in depressed patients: A review and methodological recommendations for assessment of BDNF in blood

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder and a leading cause of disability worldwide. Brain-derived neurotrophic factor (BDNF), a signaling protein responsible for promoting neuroplasticity, is highly expressed in the central nervous system but can also be found in the blood. Since impaired brain plasticity is considered a cornerstone in the pathophysiology of MDD, measurement of BDNF in blood has been proposed as a potential biomarker in MDD. The aim of our study is to systematically review the literature for the effects of antidepressant treatments on blood BDNF levels in MDD and the suitability of blood BDNF as a biomarker for depression severity and antidepressant response. We searched Pubmed® and Cochrane library up to March 2024 in a systematic manner using Medical Subject Headings (MeSH). The search resulted in a total of 42 papers, of which 30 were included in this systematic review. Generally, we found that patients with untreated MDD have a lower blood BDNF level than healthy controls. Antidepressant treatments increase blood BDNF levels, and more evidently after pharmacological than non-pharmacological treatment. Neither baseline nor change in the blood BDNF level correlates with depression severity or treatment outcome, which undermines its use as a biomarker in MDD. Our review also highlights the importance of considering factors influencing the accuracy and reproducibility of BDNF measurements. We summarize considerations to help obtain more robust blood BDNF values and compile a list of recommendations to help streamline assessment of blood BDNF levels in future studies.

Circadian rhythm of brain-derived neurotrophic factor in serum and plasma

The neurotrophic growth factor brain-derived neurotrophic factor (BDNF) plays a crucial role in various neurodegenerative and psychiatric diseases, such as Alzheimer's disease, schizophrenia and depression. BDNF has been proposed as a potential biomarker for diagnosis, prognosis and monitoring therapy. Understanding the factors influencing BDNF levels and whether they follow a circadian rhythm is essential for interpreting fluctuations in BDNF measurements. We aimed to investigate the circadian rhythm of BDNF by collecting multiple peripheral venous blood samples from young, healthy male participants at 12 different time points over 24 h. In addition, vital parameters, cortisol and insulin like growth factor 1 (IGF1) were measured to explore potential regulatory mechanisms, interfering variables and their correlations with BDNF concentration. The findings revealed that plasma BDNF did not exhibit any significant fluctuations over 24 h, suggesting the absence of a circadian rhythm. However, serum BDNF levels decreased during sleep. Furthermore, serum BDNF showed a positive correlation with heart rate but a negative correlation with IGF1. No significant correlation was observed between cortisol and BDNF or IGF1. Although plasma BDNF suggests steady-state conditions, the decline of serum BDNF during the nocturnal period could be attributed to physical inactivity and associated with reduced haemodynamic blood flow (heart rate reduction during sleep). The type of sample collection (peripheral venous cannula vs. blood sampling using a butterfly system) does not significantly affect the measured BDNF levels. The sample collection during the day did not significantly affect BDNF analysis, emphasizing the importance of considering activity levels rather than timing when designing standardized protocols for BDNF assessments.

BDNF: New Views of an Old Player in Traumatic Brain Injury

Traumatic brain injury is a common health problem affecting millions of people each year. BDNF has been investigated in the context of traumatic brain injury due to its crucial role in maintaining brain homeostasis. Val66Met is a functional single-nucleotide polymorphism that results in a valine-to-methionine amino acid substitution at codon 66 in the BDNF prodomain, which ultimately reduces secretion of BDNF. Here, we review experimental animal models as well as clinical studies investigating the role of the Val66Met single-nucleotide polymorphism in traumatic brain injury outcomes, including cognitive function, motor function, neuropsychiatric symptoms, and nociception. We also review studies investigating the role of BDNF on traumatic brain injury pathophysiology as well as circulating BDNF as a biomarker of traumatic brain injury.

Perimenopausal Physical Activity and Dementia Risk: A Systematic Review

Mixed-gender studies predominate in the current literature exploring the interaction between physical activity and dementia risk. Considering that menopause appears to contribute to females' increased risk of cognitive decline when compared to males, further clarity is required on the impact of physical activity in reducing late-life dementia risk, specifically in perimenopausal females. A literature search of MEDLINE, EMBASE, Web of Science, SCOPUS and CINAHL databases yielded fourteen studies for review. A significant inverse relationship between perimenopausal leisure time physical activity, or physical fitness, and future all-cause dementia risk was found in most studies exploring this interaction. Higher levels of perimenopausal household physical activity and combined non-leisure time physical activity also displayed a favorable impact in lowering dementia risk. A dose-response effect was demonstrated, with approximately 10 MET-hour/week of leisure time physical activity required for significant dementia risk reduction. Three of four papers exploring causality provided analyses proposed to counter the reverse causation argument, suggesting that physical activity may indeed have a protective role in reducing dementia risk post-menopause. The current systematic review provides promising results regarding the impact of pre- and perimenopausal physical activity on reducing late-life dementia risk, suggesting that promoting perimenopausal physical activity may serve as a crucial tool in mitigating the risk of post-menopausal cognitive decline.

Effects of antidepressant and antipsychotic medication on peripheral brain-derived neurotrophic factor concentration: Systematic review and meta-analysis

Brain-derived neurotrophic factor (BDNF) is an important regulatory protein in the pathophysiology of psychiatric disorders. Several studies have reported the relationship between peripheral BDNF concentrations and the use of psychoactive drugs. However, the results remain controversial. This study aimed to evaluate the effects of psychoactive drugs on BDNF concentrations and to explore the association between changes in BDNF concentrations and improvements in clinical scores. A systematic review and meta-analysis were conducted. Six electronic databases, including PubMed, Scopus, Medline, Web of Science, Google Scholar and Science Direct, were searched. Changes in BDNF concentrations were compared before and after psychoactive treatment, using the standardized mean difference (SMD) and 95 % confidence interval (95 % CI). Twenty-three studies were included. A significant increase in serum BDNF concentrations was observed after treatment with antipsychotics (SMD=0.43; 95 %CI: 0.26, 0.60) and antidepressants (SMD=0.49; 95 %CI: 0.23, 0.74). However, the plasma BDNF concentration was not affected by antidepressant and antipsychotic medication. Although an improvement in clinical scores was observed after treatment, no significant association was observed between changes in BDNF concentrations and the changes in the Positive and Negative Syndrome Scale (PANSS) and the Hamilton Depression Rating Scale (HAM-D) scores. In conclusion, antidepressants and antipsychotics increase serum BDNF concentrations.

The effect of psychedelics on the level of brain-derived neurotrophic factor: A systematic review and meta-analysis

BACKGROUND

Recent interest in the potential therapeutic effects of psychedelics has led to investigations into their influence on molecular signaling pathways within the brain.

AIMS

Integrated review and analysis of different studies in this field.

METHODS

A systematic search was conducted across international databases including Embase, Scopus, Web of Science, and PubMed from inception to 9 July 2023. Eligibility criteria encompassed published and peer-reviewed studies evaluating changes in brain-derived neurotrophic factor (BDNF) levels after psychedelic consumption.

OUTCOMES

A total of nine studies were included in our study. The meta-analysis demonstrated significantly higher BDNF levels in psychedelic consumers compared to healthy controls, with a pooled standardized mean difference of 0.26 (95% CI: 0.10-0.42, I2 = 38.51%, p < 0.001). Leave-one-out analysis indicated robustness in results upon removal of individual psychedelics. No significant publication bias was observed. The results highlight the potential influence of psychedelics on neuroplasticity by altering BDNF levels.

CONCLUSIONS

More precisely, the documented rise in BDNF levels indicates a neurobiological mechanism by which psychedelics could enhance synaptic plasticity and foster the growth of neurons. Given the limited data available on this topic, the conclusions remain uncertain. Consequently, we highly recommend additional research with more extensive sample sizes to yield more reliable evidence in this field.

Enhanced peripheral levels of BDNF and proBDNF: elucidating neurotrophin dynamics in cocaine use disorder

Brain-derived neurotrophic factor (BDNF) and its precursor, proBDNF, are known to significantly contribute to brain homeostasis, neuroplasticity, and neuronal remodeling. Although these neurotrophins are thought to have opposing roles, both play a critical part in shaping long-lasting behavioral changes following substance use. In this context, our study sought to explore the implications of these neurotrophins in the pathophysiology of cocaine use disorder (CUD). We conducted a case-control study, which included 28 individuals seeking treatment for CUD and 38 matched healthy participants. We measured peripheral neurotrophin concentrations via an enzyme-linked immunosorbent assay. Additionally, all participants were screened for cocaine-associated pathways (e.g., cocaine intake, craving intensity), along with associated psychopathological data. Our findings highlighted an increased concentration of BDNF and proBDNF in CUD individuals when compared to healthy controls (BDNF: 18092.80 ± 6844.62 vs. 11334.42 ± 5061.85 pg/ml, p < 0.001; proBDNF: 87.03 ± 33.23 vs. 55.70 ± 23.26 ng/ml, p < 0.001). We further corroborated the relationship between neurotrophin levels and CUD using a linear regression model. Nevertheless, there was no significant difference in the proBDNF to BDNF ratio between the two groups. Interestingly, our study also demonstrated the influence of factors like usage of psychotropic medications, history of psychiatric hospitalizations, and psychiatric diagnoses on neurotrophin dynamics. In conclusion, our study underscores the significance of neurotrophin fluctuations in CUD. The observed increase in BDNF and proBDNF levels could play a pivotal role in driving craving and relapse risk. Thus, a nuanced understanding of these neurobiological underpinnings in CUD might contribute to the development of more targeted and effective therapeutic strategies.

Effect of Calorie Restriction and Intermittent Fasting Regimens on Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Humans: A Systematic Review

Background: The potential positive interaction between intermittent fasting (IF) and brain-derived neurotrophic factor (BDNF) on cognitive function has been widely discussed. This systematic review tried to assess the efficacy of interventions with different IF regimens on BDNF levels and their association with cognitive functions in humans. Interventions with different forms of IF such as caloric restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE), and the Ramadan model of intermittent fasting (RIF) were targeted. Methods: A systematic review was conducted for experimental and observational studies on healthy people and patients with diseases published in EMBASE, Scopus, PubMed, and Google Scholar databases from January 2000 to December 2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements (PRISMA) for writing this review. Results: Sixteen research works conducted on healthy people and patients with metabolic disorders met the inclusion criteria for this systematic review. Five studies showed a significant increase in BDNF after the intervention, while five studies reported a significant decrease in BDNF levels, and the other six studies showed no significant changes in BDNF levels due to IF regimens. Moreover, five studies examined the RIF protocol, of which, three studies showed a significant reduction, while two showed a significant increase in BDNF levels, along with an improvement in cognitive function after RIF. Conclusions: The current findings suggest that IF has varying effects on BDNF levels and cognitive functions in healthy, overweight/obese individuals and patients with metabolic conditions. However, few human studies have shown that IF increases BDNF levels, with controversial results. In humans, IF has yet to be fully investigated in terms of its long-term effect on BDNF and cognitive functions. Large-scale, well-controlled studies with high-quality data are warranted to elucidate the impact of the IF regimens on BDNF levels and cognitive functions.

Brain-derived neurotrophic factor (BDNF) as a potential marker of endometriosis: a systematic review and meta-analysis

BACKGROUND

The existing literature on the association between BDNF protein levels and endometriosis presents inconsistent findings. This systematic review and meta-analysis aim to synthesize the available evidence and evaluate the possible relationship between BDNF protein levels and endometriosis.

METHODS

Electronic databases (PubMed, Embase, Scopus, PsycINFO, and Web of Science) were used to conduct a comprehensive literature search from inception to June 2023. The search strategy included relevant keywords and medical subject headings (MeSH) terms related to BDNF, endometriosis, and protein levels. A random-effects model was used for the meta-analysis, and to explore heterogeneity subgroup analyses were performed. funnel plots and statistical tests were used for assessing the publication bias.

RESULTS

A total of 12 studies were included. The pooled standardized mean difference (SMD) of BDNF levels between women with endometriosis and controls was 0.87 (95% confidence interval [CI] 0.34 to 1.39, p = 0.001; I2 = 93%). The results showed that blood levels of BDNF are significantly higher in endometriosis patients (SMD: 1.13 95% CI 0.54 to 1.73, p = 0.0002; I2 = 93%). No significant publication bias was observed based on the results of Egger's regression test ((p = 0.15).

CONCLUSION

This study revealed a significant difference between patients diagnosed with endometriosis and healthy control in the level of BDNF. The results indicate that women with endometriosis have higher levels of BDNF. Further studies are needed to be undertaken to investigate the role of BDNF in endometriosis pathophysiology and the diagnostic value of BDNF in endometriosis.

Effect of cannabis use on blood levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF): A systematic review and meta-analysis

BACKGROUND

The impact of cannabis uses on blood levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) remains uncertain, with conflicting findings reported in the literature. BDNF and NGF both are essential proteins for neuron's growth, and their dysregulation is seen in various mental disorders. This study aims to evaluate the relationship between cannabis usage and BDNF and NGF levels due to their potential implications for mental health.

METHODS

A comprehensive search of electronic databases was performed using appropriate MeSH terms and keywords. Inclusion criteria comprised human studies investigating the relationship between cannabis use and BDNF and NGF levels.

RESULTS

A total of 11 studies met the inclusion criteria and were included. The pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of BDNF (random-effects model, standardized mean differences [SMD] = .26, 95% CI -.34 to .76, p = .40). The results of our subgroup analysis based on BDNF source showed a nonsignificant between-group difference. For NGF levels, four studies were included, the pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of NGF (random-effects model, SMD = -.60, 95% CI -1.43 to -.23, p = .16). In both analyses, high heterogeneity was observed among the included studies which is a notable limitation to current meta-analysis.

CONCLUSION

This systematic review highlights the need for further research to elucidate the relationship between cannabis use and these neurotrophic factors. A better understanding of these associations can contribute to our knowledge of the neurobiological effects of cannabis and inform potential implications for mental health, cognitive function, and neurodegenerative disorders.

Effect of alcohol on Brain-Derived Neurotrophic Factor (BDNF) blood levels: a systematic review and meta-analysis

Brain-Derived Neurotrophic Factor (BDNF) is a vital protein involved in neuronal development, survival, and plasticity. Alcohol consumption has been implicated in various neurocognitive deficits and neurodegenerative disorders. However, the impact of alcohol on BDNF blood levels remains unclear. This systematic review and meta-analysis aimed to investigate the effect of alcohol consumption on BDNF blood levels. A comprehensive search of electronic databases was conducted to identify relevant studies. Eligible studies were selected based on predefined inclusion criteria. Data extraction was performed, and methodological quality was assessed using appropriate tools. A meta-analysis was conducted to estimate the overall effect size of alcohol consumption on BDNF levels. A total of 25 studies met the inclusion criteria and were included in the final analysis. Alcohol use and BDNF blood levels were significantly correlated, according to the meta-analysis (p = 0.008). Overall, it was discovered that drinking alcohol significantly decreased BDNF levels (SMD: - 0.39; 95% CI: - 0.68 to - 0.10; I2: 93%). There was a non-significant trend suggesting that alcohol withdrawal might increase BDNF levels, with an SMD of 0.26 (95% CI: - 0.09 to 0.62; I2: 86%; p = 0.14). Subgroup analysis based on the source of BDNF demonstrated significant differences between the subgroups (p = 0.0008). No significant publication bias was observed. This study showed that alcohol consumption is associated with a significant decrease in BDNF blood levels. The findings suggest a negative impact of alcohol on BDNF levels regardless of alcohol dosage. Further studies are needed to strengthen the evidence and elucidate the underlying mechanisms.

Brain-derived neurotrophic factor and nerve growth factor expression in endometriosis: A systematic review and meta-analysis

Endometriosis is diagnosed by laparoscopic surgery. The availability of biomarkers can help understand the pathophysiology and aid in the diagnosis of the condition. In this context, this review aimed to examine levels of expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are increased amongst patients with endometriosis and if they can serve as a potential biomarker. PubMed, CENTRAL, Scopus, Web of Science, and Embase databases were searched for studies comparing BDNF or NGF levels amongst endometriosis patients and controls. Data were pooled for serum and tissue levels of BDNF and NGF. Ten fulfilled the inclusion criteria. On comparing BDNF levels, it was noted that endometrial tissue had significantly higher expression of BDNF levels as compared to controls (SMD: 1.73 95% CI: 0.64, 2.82 I2 = 89%). Similarly, the meta-analysis found significantly higher serum levels of BDNF in endometriosis patients as compared to controls (SMD: 1.66 95% CI: 0.73, 2.59 I2 = 95%). Pooled analysis showed significantly increased levels of NGF in endometrial tissue as compared to controls (SMD: 4.15 95% CI: 0.11, 8.18 I2 = 98%) but with unstable results on sensitivity analysis. Only one study showed higher levels of NGF in serum amongst endometriosis patients. Limited data shows higher expression of BDNF in endometrial lesions and increased serum levels of BDNF in endometriosis patients. Similar results were noted for NGF but with very scarce data. Further research is needed to establish BDNF and NGF as suitable biomarkers for the disease.

Brain-derived neurotrophic factor (BDNF) levels in children and adolescents before and after stimulant use a systematic review and metanalysis

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder associated with cognitive, social, and academic impairment. Neurotrophins, particularly brain-derived neurotrophic factor (BDNF), have been implicated in the pathophysiology of ADHD and response to stimulant treatment. This review aims to investigate the relationship between BDNF levels in ADHD before and after treatment with stimulants in childhood.

METHODS

This systematic review followed PRISMA-P guidelines and included 19 studies from PubMed, EMBASE, Cochrane, Capes Periodic, and Lilacs databases. The studies were evaluated for risk of bias and level of evidence.

RESULTS

There was no significant difference in peripheral BDNF levels in ADHD children before or after methylphenidate treatment. Additionally, there was no statistically significant difference in BDNF levels between children with ADHD and controls.

DISCUSSION

Understanding the role of BDNF in ADHD may provide insight into the disorder's pathophysiology and facilitate the development of biological markers for clinical use.

CONCLUSION

Our findings suggest that BDNF levels are not significantly affected by methylphenidate treatment in ADHD children and do not differ from controls.

SYSTEMATIC REVIEW REGISTRATION

"Brain-derived neurotrophic factor (BDNF) levels in children and adolescents before and after stimulant use: a systematic review". Number CRD42021261519.

BDNF promotes mouse follicular development and reverses ovarian aging by promoting cell proliferation

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays an important role in ovarian function including follicle development and oocyte maturation, and embryonic development. However, whether BDNF treatment can reimpose ovarian aging and impaired fertility remains elusive. In this study, we investigated the reproductive outcomes of BDNF treatment and potential mechanisms in aged mice.

METHOD

"Aged" mice (35-37 weeks old, n = 68) were treated with recombinant human BDNF protein (rhBDNF, 1 µg/200 µL) through daily intraperitoneal (IP) injection for 10 days with/without ovulation induction. Reproductive age mice (8-10 weeks old, n = 28) were treated with ANA 12 (a selective BDNF receptor, TrkB antagonist) through daily IP injection for 5 days with/without ovulation induction. Ovarian function was assessed by ovarian weight, number of follicles, and sex hormone productions. Following induction of ovulation, the number of total oocytes or abnormal oocytes, and blastocyst formation were assessed. Reproductive functions of the mice were evaluated, including pregnancy rate, mating duration for conception, implantation sites, litter size, and weight of offspring. Finally, the molecular mechanism of the effects of BDNF on ovarian cell functions in mice were examined by Western blot and immunofluorescence.

RESULTS

rhBDNF treatment increased the ovarian weight, number of follicles, number and quality of oocytes including increased blastocysts formation, blood estrogen levels, and pregnancy rate in 35-37-week-old mice. Conversely, BDNF receptor antagonist, ANA 12, treatment decreased the ovarian volume and number of antral follicles and increased the proportion of abnormal oocytes in 8-10-week-old mice. We further demonstrated that BDNF treatment promoted ovarian cell proliferation as well as activation of TrkB and cyclinD1-creb signalling.

CONCLUSION

We demonstrated that ten consecutive days of daily IP injection of rhBDNF rescued ovarian function in aged mice. Our results further indicate that TrkB and cyclin D1-creb signaling may underlie the BDNF function in ovaries. Targeting BDNF-TrkB signaling is a potential novel therapeutic strategy to reverse ovarian aging.

Hormonal contraception and cognition: Considering the influence of endogenous ovarian hormones and genes for clinical translation

Despite the well-known influence of ovarian hormones on the brain and widespread use of hormonal contraception (HC) since the 1960s, our knowledge of HC's cognitive effects remains limited. To date, the cognitive findings have been inconsistent. In order to establish what might make HC studies more consistent, we surveyed the literature on HCs and cognition to determine whether studies considered HC formulation, phase, pharmacokinetics, duration, and gene interactions, and assessed whether oversight of these factors might contribute to variable findings. We found that synthetic HC hormones exert dose-dependent effects, the day of oral contraceptive (Pill) ingestion is critical for understanding cognitive changes, and gene-cognition relationships differ in women taking the Pill likely due to suppressed endogenous hormones. When these factors were overlooked, results were not consistent. We close with recommendations for research more likely to yield consistent findings and be therefore, translatable.

Proline-rich polypeptides (Colostrinin®/COLOCO®) modulate BDNF concentration in blood affecting cognitive function in adults: A double-blind randomized placebo-controlled study

Proline-rich polypeptides (PRPs complex also known as COLOCO®, Colostrinin®) consist of low-molecular weight peptides ranging up to 10 kDa, isolated from the bovine colostrum obtained up to 48 h postpartum. PRPs have been shown to affect processes involved in inflammation, brain aging, and neurodegeneration. The aim of this study was to investigate the effect of Colostrinin® (COLOCO®) on the cognitive abilities of healthy volunteers in three different age groups using the CANTAB tool in a double-blind randomized placebo-controlled study. BDNF serum level was used as a physicochemical marker of improvement of the cognitive skills. Three hundred and sixty-one healthy volunteers were divided into three study groups aged 18-24, 25-54, and 55-75; each group was then divided into two subgroups which took either placebo or tested lozenge with 120 μg of PRPs for the period of 4 months. The CANTAB battery test was used to measure the efficacy of PRP in the context of cognitive functioning. After the treatment with COLOCO®, we observed differences within MoCA score in the oldest patients, improvement in DMS and drop in PAL scores within the youngest group, drop in RTI and improvement in RVP scores within the middle-aged group. It was observed that serum BDNF level increased in all study groups which confirms cognitive improvement. In conclusion, we have shown that Colostrinin® exhibits cognitive enhancing effects, probably through the modulation of BDNF concentrations.

BDNF as a biomarker for neuropathic pain: Consideration of mechanisms of action and associated measurement challenges

INTRODUCTION

The primary objective of this paper is to (1) provide a summary of human studies that have used brain derived neurotrophic factor (BDNF) as a biomarker, (2) review animal studies that help to elucidate the mechanistic involvement of BDNF in the development and maintenance of neuropathic pain (NP), and (3) provide a critique of the existing measurement techniques to highlight the limitations of the methods utilized to quantify BDNF in different biofluids in the blood (i.e., serum and plasma) with the intention of presenting a case for the most reliable and valid technique. Lastly, this review also explores potential moderators that can influence the measurement of BDNF and provides recommendations to standardize its quantification to reduce the inconsistencies across studies.

METHODS

In this manuscript we examined the literature on BDNF, focusing on its role as a biomarker, its mechanism of action in NP, and critically analyzed its measurement in serum and plasma to identify factors that contribute to the discrepancy in results between plasma and serum BDNF values.

RESULTS

A large heterogenous literature was reviewed that detailed BDNF's utility as a potential biomarker in healthy volunteers, patients with chronic pain, and patients with neuropsychiatric disorders but demonstrated inconsistent findings. The literature provides insight into the mechanism of action of BDNF at different levels of the central nervous system using animal studies. We identified multiple factors that influence the measurement of BDNF in serum and plasma and based on current evidence, we recommend assessing serum BDNF levels to quantify peripheral BDNF as they are more stable and sensitive to changes than plasma BDNF.

CONCLUSION

Although mechanistic studies clearly explain the role of BDNF, results from human studies are inconsistent. More studies are needed to evaluate the methodological challenges in using serum BDNF as a biomarker in NP.

Brain-derived neurotrophic factor (BDNF) in perinatal depression: Side show or pivotal factor?

Perinatal depression is the most common psychiatric complication of pregnancy, with its detrimental effects on maternal and infant health widely underrated. There is a pressing need for specific molecular biomarkers, with pregnancy-related decline in brain-derived neurotrophic factor (BDNF) in the blood and downregulation of TrkB receptor in the brain reported in clinical and preclinical studies. In this review, we explore the emerging role of BDNF in reproductive biology and discuss evidence suggesting its deficiency as a risk factor for perinatal depression. With the increasing evidence for restoration of serum BDNF levels by antidepressant therapy, the strengthening association of perinatal depression with deficiency of BDNF supports its potential as a surrogate endpoint for preclinical and clinical studies.

Brain-Derived Neurotrophic Factor (BDNF) as an Indicator for Effects of Cognitive Behavioral Therapy (CBT): A Systematic Review

Brain-derived neurotrophic factor (BDNF) is a protein affecting survival of existing neurons and neuronal maturation. Patients suffering from several mental disorders exhibit reduced BDNF levels comparing to healthy population. In this systematic review we aim to evaluate the effect of broadly defined cognitive behavioral therapy (CBT) on BDNF levels in psychiatric patients. A literature search was performed using PubMed and Google Scholar data bases. The resources were searched between 14 January and 3 February 2022. Following the inclusion criteria, a total of 10 randomized-controlled trials were included. The results of our research indicate that BDNF levels might be considered an indicator of a result achieved in psychotherapy of cognitive functions. However, no such correlation was observed for mindfulness-based practices intended to lower stress levels or improve the quality of life. It is important to notice that present research showed no consistent correlation between the increase in BDNF levels and the perceived effectiveness of the procedures. Thus, the exact role of BDNF remains unknown, and so far, it cannot be taken as an objective measure of the quality of the interventions.

Effect of Whole-Body Vibration on Serum Levels of Brain Derived Neurotrophic Factor and Cortisol in Young, Healthy Women

Vibration exercises on a platform (whole-body vibration, WBV), widely used in rehabilitation, sports medicine, and fitness, is an alternative to strength effort. The presented study assessed the effect of a 12-week cycle of vibration training on the serum concentrations of brain-derived neurotrophic factor (BDNF) and cortisol in young women (trial ID: ACTRN 12621000114842). Volunteers were assigned to three groups: performing exercises on a vibrating platform (n = 17), performing identical exercises without a platform (n = 12), and passive control group (n = 17). The concentration of BDNF and cortisol was assessed four times: before the first training session, 5 min after it, also before, and 5 min after the last training session. There were no statistically significant changes in the groups or among groups for both substances. WBV in the presented form did not increase the secretion of BDNF and is not a stressful stimulus.

Age-related changes in Folliculogenesis and potential modifiers to improve fertility outcomes - A narrative review

Reproductive aging is characterized by a decline in oocyte quantity and quality, which is directly associated with a decline in reproductive potential, as well as poorer reproductive success and obstetrical outcomes. As women delay childbearing, understanding the mechanisms of ovarian aging and follicular depletion have become increasingly more relevant. Age-related meiotic errors in oocytes are well established. In addition, it is also important to understand how intraovarian regulators change with aging and how certain treatments can mitigate the impact of aging. Individual studies have demonstrated that reproductive pathways involving antimullerian hormone (AMH), vascular endothelial growth factor (VEGF), neurotropins, insulin-like growth factor 1 (IGF1), and mitochondrial function are pivotal for healthy oocyte and cumulus cell development and are altered with increasing age. We provide a comprehensive review of these individual studies and explain how these factors change in oocytes, cumulus cells, and follicular fluid. We also summarize how modifiers of folliculogenesis, such as vitamin D, coenzyme Q, and dehydroepiandrosterone (DHEA) may be used to potentially overcome age-related changes and enhance fertility outcomes of aged follicles, as evidenced by human and rodent studies.

What is there to know about the effects of progestins on the human brain and cognition?

Progestins are an important component of hormonal contraceptives (HCs) and hormone replacement therapies (HRTs). Despite an increasing number of studies elucidating the effects of HCs and HRTs, little is known about the effects of different types of progestins included in these medications on the brain. Animal studies suggest that various progestins interact differently with sex steroid, mineralocorticoid and glucocorticoid receptors and have specific modulatory effects on neurotransmitter systems and on the expression of neuropeptides, suggesting differential impacts on cognition and behavior. This review focuses on the currently available knowledge from human behavioral and neuroimaging studies pooled with evidence from animal research regarding the effects of progestins on the brain. The reviewed information is highly relevant for improving women's mental health and making informed choices regarding specific types of contraception or treatment.

Pre and postnatal exposure to mercury and sexual development in 9-year-old children in Spain: The role of brain-derived neurotrophic factor

Early exposure to mercury has been related to endocrine disruption. Steroid hormones play a crucial role in neural cell migration, differentiation, etc., as well as protecting against several neurotoxic compounds. We investigate the relation between mercury exposure and children's sexual development, and we evaluate the possible influence of different brain-derived neurotrophic factor (BDNF) polymorphisms on this association. Our study sample comprised 412 9-year-old children participating in the INMA cohort (2004-2015). Mercury concentrations were measured at birth (cord blood) and at 4 and 9 years of age (hair). Sexual development was assessed by levels of sex steroid hormones (estradiol and testosterone) in saliva and the Tanner stages of sex development at 9 years (categorized as 1: prepuberty and >1: pubertal onset). Covariates and confounders were collected through questionnaires during pregnancy and childhood. Polymorphisms in the BDNF gene were genotyped in cord blood DNA. Multivariate linear regression analyses were performed between mercury levels and children's sexual development by sex. Effect modification by genetic polymorphisms and fish intake was assessed. We found marginally significant inverse associations between postnatal exposure to mercury (at 9 years) and testosterone levels (β[95%CI] = -0.16[-0.33,0.001], and -0.20[-0.42,0.03], for boys and girls, respectively). Additionally, we found that prenatal mercury was negatively associated with Tanner stage >1 in boys. Finally, we found significant genetic interactions for some single nucleotide polymorphisms in the BDNF gene. In conclusion, pre and postnatal exposure to mercury seems to affect children's sexual development and BDNF may play a role in this association, but further research would be needed.

Sex Hormones, Sleep, and Memory: Interrelationships Across the Adult Female Lifespan

As the population of older adults grows, so will the prevalence of aging-related conditions, including memory impairments and sleep disturbances, both of which are more common among women. Compared to older men, older women are up to twice as likely to experience sleep disturbances and are at a higher risk of cognitive decline and Alzheimer's disease and related dementias (ADRD). These sex differences may be attributed in part to fluctuations in levels of female sex hormones (i.e., estrogen and progesterone) that occur across the adult female lifespan. Though women tend to experience the most significant sleep and memory problems during the peri-menopausal period, changes in memory and sleep have also been observed across the menstrual cycle and during pregnancy. Here, we review current knowledge on the interrelationships among female sex hormones, sleep, and memory across the female lifespan, propose possible mediating and moderating mechanisms linking these variables and describe implications for ADRD risk in later life.

Blood levels of brain-derived neurotrophic factor (BDNF) in people with multiple sclerosis (MS): A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis is an autoimmune demyelinating disease marked by the involvement of multiple pathophysiological pathways, including BDNF. BDNF (brain-derived neurotrophic factor) is one of the main neurotrophic factors in the adult brain. The amount of BDNF in the blood can be utilized as a surrogate for the central expression of this marker. Given contradicting reports, we set out to answer the question, "How do blood levels of BDNF differ in people with multiple sclerosis (PwMS) compared to controls?"

METHODS

We performed a thorough search in MEDLINE, EMBASE, Web of Science, and the Cochrane Library databases, resulting in 13 eligible investigations. Eleven studies compared BDNF in serum of PwMS versus healthy controls (HC), and two studies provided BDNF levels in the plasma of PwMs. R version 4.0.4 was used for meta-analysis and visualizations. Mean difference (MD) was used for the measurement of effect size.

RESULTS

The final analysis included thirteen studies with 689 patients with MS and 583 controls. The preliminary results indicated that MS patients had statistically significant lower levels of BDNF than controls: SMD -5.1992 (95% CI [-8.4488; -1.9496], p-value < 0.0001. Additionally, subgroup analysis revealed a statistically significant difference in serum and plasma levels (p-value=0.01). Performing univariate meta-regression, disease duration and the proportion of males had, respectively, a significant negative and positive correlation with BDNF levels.

CONCLUSION

Circulating levels of BDNF are decreased in MS. Future studies should investigate the role of BDNF as a biomarker of disease severity and/or progression for a personalized approach to MS.

Mentha pulegium L. (Pennyroyal, Lamiaceae) Extracts Impose Abortion or Fetal-Mediated Toxicity in Pregnant Rats; Evidenced by the Modulation of Pregnancy Hormones, MiR-520, MiR-146a, TIMP-1 and MMP-9 Protein Expressions, Inflammatory State, Certain Related Signaling Pathways, and Metabolite Profiling via UPLC-ESI-TOF-MS

Pregnant women usually turn to natural products to relieve pregnancy-related ailments which might pose health risks. Mentha pulegium L. (MP, Lamiaceae) is a common insect repellent, and the present work validates its abortifacient capacity, targeting morphological anomalies, biological, and behavioral consequences, compared to misoprostol. The study also includes untargeted metabolite profiling of MP extract and fractions thereof viz. methylene chloride (MecH), ethyl acetate (EtOAc), butanol (But), and the remaining liquor (Rem. Aq.) by UPLC-ESI-MS-TOF, to unravel the constituents provoking abortion. Administration of MP extract/fractions, for three days starting from day 15th of gestation, affected fetal development by disrupting the uterine and placental tissues, or even caused pregnancy termination. These effects also entailed biochemical changes where they decreased progesterone and increased estradiol serum levels, modulated placental gene expressions of both MiR-(146a and 520), decreased uterine MMP-9, and up-regulated TIMP-1 protein expression, and empathized inflammatory responses (TNF-α, IL-1β). In addition, these alterations affected the brain's GFAP, BDNF, and 5-HT content and some of the behavioral parameters escorted by the open field test. All these incidences were also perceived in the misoprostol-treated group. A total of 128 metabolites were identified in the alcoholic extract of MP, including hydroxycinnamates, flavonoid conjugates, quinones, iridoids, and terpenes. MP extract was successful in terminating the pregnancy with minimal behavioral abnormalities and low toxicity margins.

Brain-derived neurotrophic factor and mood in perimenopausal depression

BACKGROUND

Previous work implicates high pro-inflammatory biomarkers in mood disturbance and low brain-derived neurotrophic factor (BDNF) levels in major depression. However, in hormonally-sensitive premenstrual dysphoric disorder (PMDD), BDNF levels are higher when mood is worse. Perimenopausal depression has not been studied to date. We evaluated whether BDNF and inflammatory cytokines predict mood symptoms across the menstrual cycle in hormonally-sensitive perimenopausal depression symptoms.

METHODS

Data from 49 time points derived from mid-to-late follicular phase [M/L-FP] and peri‑menstrual assessments of 14 perimenopausal women ages 38-52 with ovulatory menstrual cycles 24-35 days long across 1-2 cycles for mood symptoms, BDNF levels, cytokines, gonadal steroids. Depression was assessed with Montgomery-Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI); irritability with Kellner Symptom Questionnaire Anger-Hostility subscale (SQ); overall psychological distress with Profile of Mood States (POMS). Mixed models were run on dependent measures of MADRS (primary endpoint) and other mood outcomes (BDI, POMS, SQ) with independent variables of interest (each biomarker, cycle phase), controlling for cycle number and participant.

RESULTS

After FDR adjustment, BDNF levels showed consistent significant positive relationships to MADRS (β=0.00053; p = 0.0028), POMS (β=0.00153; p = 0.0394), SQ (β=0.00053; p = 0.0067), and BDI (β=0.00039; p = 0.0231). Cycle phase did not affect this relationship. No other biomarker consistently predicted affective symptom severity.

LIMITATIONS

Small sample size and large number of comparisons.

CONCLUSION

In women with perimenopausal depression symptoms, BDNF is elevated in association with more severe mood symptomatology, resembling the pattern in hormonally-sensitive PMDD and suggesting a hormonally-sensitive mood disorder biomarker profile distinct from that of major depression.

Intrinsic innervation of the ovary and its variations in the rat senescence process

Ovarian functions decrease with perimenopause. The ovary has extrinsic innervation, but the neural influence on ovarian functions and dysfunction is not well-studied. The present study aimed to biochemically and morphometrically characterize the intrinsic neurons in ovaries from young adult, middle-aged, and senescent Long Evans CII-ZV rats (3, 12, and 15 months old, respectively). Ovaries were extracted from four rats of each age group (n = 12 total), cryopreserved, and processed for immunofluorescence studies with the primary NeuN/β-tubulin and NeuN/tyrosine hydroxylase (TH) antibodies. The soma area and number of intrinsic neurons in the ovarian stroma, surrounding follicles, corpus luteum, or cyst were evaluated. The intrinsic neurons were grouped in cluster-like shapes in ovarian structures. In senescent rats, the intrinsic neurons were mainly localized in the ovarian stroma and around the cysts. The number of neurons was lower in senescent rats than in young adult rats (p < 0.05), but the soma size was larger than in young adult rats. Immunoreactivity to TH indicated the presence of noradrenergic neurons in the ovary with the same characteristics as NeuN/β-tubulin, which indicates that they are part of the same neuronal group. Taken together, the findings indicate that the intrinsic neurons may be related to the loss of ovarian functions associated with aging.

TrkB agonist antibody ameliorates fertility deficits in aged and cyclophosphamide-induced premature ovarian failure model mice

Premature ovarian failure (POF) is a leading cause of women's infertility without effective treatment. Here we show that intravenous injection of Ab4B19, an agonistic antibody for the BDNF receptor TrkB, penetrates into ovarian follicles, activates TrkB signaling, and promotes ovary development. In both natural aging and cyclophosphamide-induced POF models, treatment with Ab4B19 completely reverses the reduction of pre-antral and antral follicles, and normalizes gonadal hormone. Ab4B19 also attenuates gonadotoxicity and inhibits apoptosis in cyclophosphamide-induced POF ovaries. Further, treatment with Ab4B19, but not BDNF, restores the number and quality of oocytes and enhances fertility. In human, BDNF levels are high in granulosa cells and TrkB levels increase in oocytes as they mature. Moreover, BDNF expression is down-regulated in follicles of aged women, and Ab4B19 activates TrkB signaling in human ovary tissue ex vivo. These results identify TrkB as a potential target for POF with differentiated mechanisms, and confirms superiority of TrkB activating antibody over BDNF as therapeutic agents.

Physical Exercise and Brain-Derived Neurotrophic Factor Concentration in Children and Adolescents: A Systematic Review With Meta-Analysis

PURPOSE

To systematically review the literature on the relationship between physical activity and the effect of physical training on brain-derived neurotrophic factor (BDNF) concentrations in children and adolescents.

METHODS

The searches were conducted in the databases: PubMed, ScienceDirect, Web of Science, Scopus, SPORTDiscus, Latin American and Caribbean Center for Science Information of Health, and SciELO. All original studies that analyzed the relationship between the practice of physical activity and the effect of physical training on plasma and serum BDNF concentrations in children and adolescents were included. The standardized mean difference (SMD), correlation coefficient (r), and 95% confidence interval were calculated.

RESULTS

Eleven studies were selected, totaling 1424 children and adolescents. Cross-sectional studies indicated a significant inverse relationship between physical activity and BDNF concentrations in boys (r = -.117 [-.222, -.009]; P = .033), but not in girls (P = .230). Adolescent athletes tend to have lower serum, but higher plasma BDNF concentrations than sedentary ones (SMD = -0.677 [0.188]; P < .001). An increase in serum BDNF was observed after physical training (SMD = 0.437 [0.183]; P = .017), with no effect in the control group (SMD = 0.235 [0.193]; P = .225).

CONCLUSIONS

Adolescent athletes tend to show lower serum, but higher plasma BDNF concentrations compared with sedentary individuals. Furthermore, physical training seems to increase serum BDNF concentrations in sedentary adolescents to a small extent.

Gray Matter Volume Variability in Young Healthy Adults: Influence of Gender Difference and Brain-Derived Neurotrophic Factor Genotype

Although brain gray matter (GM) plastically changes during short-term training, it is still unclear whether brain structures are stable for short periods (several months). Therefore, this study aimed to re-test the short-term variability of GM volumes and to clarify the effect of factors (gender and BDNF-genotype) expected to contribute to such variability. The subjects comprised 41 young healthy adults. T1-weighted images were acquired twice with an interval of approximately 4 months using a 3 T-MRI scanner. Voxel-based morphometry (VBM) was used to calculate GM volumes in 47 regions. The intraclass correlation coefficient (ICC) and Test–retest variability (%TRV) were used as indices of variability. As a result, the ICCs in 43 regions were excellent (ICC > 0.90) and those in 3 regions were good (ICC > 0.80), whereas the ICC in the thalamus was moderate (ICC = 0.694). Women had a higher %TRV than men in 5 regions, and %TRV of the Val66Val group was higher than that of the Met carrier group in 2 regions. Moreover, the Female-Val66Val group had a higher %TRV than the Male-Met carrier group in 3 regions. These results indicate that although the short-term variability of GM volumes is small, it is affected by within-subject factors.

Improving Clinical, Cognitive, and Psychosocial Dysfunctions in Patients with Schizophrenia: A Neurofeedback Randomized Control Trial

Objectives

The aim of this study was to use neurofeedback (NF) training as the add-on therapy in patients with schizophrenia to improve their clinical, cognitive, and psychosocial condition. The study, thanks to the monitoring of various conditions, quantitative electroencephalogram (QEEG) and brain-derived neurotrophic factor (BDNF), was supposed to give an insight into mechanisms underlying NF training results.

Methods

Forty-four male patients with schizophrenia, currently in a stable, incomplete remission, were recruited into two, 3-month rehabilitation programs, with standard rehabilitation as a control group (R) or with add-on NF training (NF). Pre- and posttherapy primary outcomes were compared: clinical (Positive and Negative Syndrome Scale (PANSS)), cognitive (Color Trails Test (CTT), d2 test), psychosocial functioning (General Self-Efficacy Scale (GSES), Beck Cognitive Insight Scale (BCIS), and Acceptance of Illness Scale (AIS)), quantitative electroencephalogram (QEEG), auditory event-related potentials (ERPs), and serum level of BDNF. Results. Both groups R and NF improved significantly in clinical ratings (Positive and Negative Syndrome Scale (PANSS)). In-between analyses unveiled some advantages of add-on NF therapy over standard rehabilitation. GSES scores improved significantly, giving the NF group of patients greater ability to cope with stressful or difficult social demands. Also, the serum-level BDNF increased significantly more in the NF group. Post hoc analyses indicated the possibility of creating a separate PANSS subsyndrome, specifically related to cognitive, psychosocial, and BDNF effects of NF therapy.

Conclusions

Neurofeedback can be effectively used as the add-on therapy in schizophrenia rehabilitation programs. The method requires further research regarding its clinical specificity and understanding mechanisms of action.

Association Between Components of Cognitive Reserve and Serum BDNF in Healthy Older Adults

Background: The brain-derived neurotrophic factor (BDNF) protein has been shown to have a prominent role in neuron survival, growth, and function in experimental models, and the BDNF Val66Met polymorphism which regulates its expression has been linked to resilience toward the effects of aging on cognition. Cognitively stimulating activity is linked to both increased levels of BDNF in the brain, and protection against age-related cognitive decline. The aim of this study was to investigate the associations between serum BDNF levels, the BDNF Val66Met genotype, and components of cognitive reserve in early and mid-life, measured with the Lifetime of Experiences Questionnaire (LEQ). Methods: Serum BDNF levels were measured cross-sectionally in 156 participants from the Tasmanian Healthy Brain Project (THBP) cohort, a study examining the potential benefits of older adults engaging in a university-level education intervention. Multiple linear regression was used to estimate serum BDNF's association with age, education, gender, BDNF Val66Met genotype, later-life university-level study, and cognitively stimulating activities measured by the LEQ. Results: Serum BDNF in older adults was associated with early life education and training, increasing 0.007 log(pg/ml) [95%CI 0.001, 0.012] per unit on the LEQ subscale. Conversely, education and training in mid-life were associated with a -0.007 log(pg/ml) [-0.012, -0.001] decrease per unit on the LEQ subscale. Serum BDNF decreased with age (-0.008 log(pg/ml) [-0.015, -0.001] per year), and male gender (-0.109 log(pg/ml) [-0.203, -0.015]), but mean differences between the BDNF Val66Met polymorphisms were not significant (p = 0.066). All effect sizes were small, with mid-life education and training having the largest effect size ( η p 2 = 0.044). Conclusion: Education in both early and mid-life explained small but significant amounts of variance in serum BDNF levels, more than age or gender. These effects were opposed and independent, suggesting that education at different stages of life may be associated with different cognitive and neural demands. Education at different stages of life may be important covariates when estimating associations between other exposures and serum BDNF.

Moderators of gene-outcome associations following traumatic brain injury

The field of genomics is the principal avenue in the ongoing development of precision/personalised medicine for a variety of health conditions. However, relating genes to outcomes is notoriously complex, especially when considering that other variables can change, or moderate, gene-outcome associations. Here, we comprehensively discuss moderation of gene-outcome associations in the context of traumatic brain injury (TBI), a common, chronically debilitating, and costly neurological condition that is under complex polygenic influence. We focus our narrative review on single nucleotide polymorphisms (SNPs) of three of the most studied genes (apolipoprotein E, brain-derived neurotrophic factor, and catechol-O-methyltransferase) and on three demographic variables believed to moderate associations between these SNPs and TBI outcomes (age, biological sex, and ethnicity). We speculate on the mechanisms which may underlie these moderating effects, drawing widely from biomolecular and behavioural research (n = 175 scientific reports) within the TBI population (n = 72) and other neurological, healthy, ageing, and psychiatric populations (n = 103). We conclude with methodological recommendations for improved exploration of moderators in future genetics research in TBI and other populations.

BDNF Impact on Biological Markers of Depression-Role of Physical Exercise and Training

Depression is the most common and devastating psychiatric disorder in the world. Its symptoms, especially during the pandemic, are observed in all age groups. Exercise training (ET) is well known as a non-pharmacological strategy to alleviate clinical depression. The brain-derived neurotrophic factor (BDNF) is one of the biological factors whose expression and secretion are intensified in response to ET. BDNF is also secreted by contracted skeletal muscle that likely exerts para-, auto- and endocrine effects, supporting the crosstalk between skeletal muscle and other distant organs/tissues, such as the nervous system. This finding suggests that they communicate and work together to induce improvements on mood, cognition, and learning processes as BDNF is the main player in the neurogenesis, growth, and survival of neurons. Therefore, BDNF has been recognized as a therapeutic factor in clinical depression, especially in response to ET. The underlying mechanisms through which ET impacts depression are varied. The aim of this review was to provide information of the biological markers of depression such as monoamines, tryptophan, endocannabinoids, markers of inflammatory processes (oxidative stress and cytokines) stress and sex hormones and their relationship to BDNF. In addition, we reviewed the effects of ET on BNDF expression and how it impacts depression as well as the potential mechanisms mediating this process, providing a better understanding of underlying ET-related mechanisms in depression.

Plasma level of brain-derived neurotrophic factor (BDNF) in patients with postpartum depression

Postpartum depression occurs in 10-15% of mothers. Brain-derived neurotrophic factor (BDNF) is a nerve growth factor that plays a role in neuroplasticity. We hypothesized that the concentration of BDNF is related to reproduction and childbirth, and that women with postpartum depression show alteration in BDNF level. A total of 104 pregnant women was selected as subjects, and 60 non-pregnant women were selected as normal controls. Symptoms of depression were evaluated in the pregnant study subjects using the diagnostic criteria outlined in the Edinburgh Postnatal Depression Scale (EPDS). The pregnant subjects were divided into three groups of perinatal non-depressed controls (n = 61), postpartum depression-recovery (n = 18), and postpartum depression (n = 25). The plasma concentration of BDNF was higher in the pregnant group than in non-pregnant controls and lower in the postpartum depression group at 6 weeks after delivery than in the perinatal non-depressed group. In the postpartum depression-recovery group, the BDNF concentration increased at 6 weeks after delivery compared to that at 24 weeks of gestation. This study found significant changes in plasma BDNF concentration in depressed pregnant women.

Sex differences in the association between serum BDNF and cognitive impairment in schizophrenia patients using various antipsychotics

BACKGROUND

Cognitive impairment is one of the core symptoms of schizophrenia patients. There are often various differences in the efficacy of different antipsychotics in the treatment of cognitive impairment by sex. The purpose of this study was to explore whether there are gender differences in the association between serum BDNF levels and cognitive performance in patients with schizophrenia taking different antipsychotics.

METHODS

We used Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to assess the cognitive function of three groups of schizophrenia patients (420 on clozapine, 183 on risperidone, 215 on typical antipsychotic drugs) and 467 healthy controls. Positive and Negative Syndrome Scale (PANSS) was used to assess schizophrenia symptoms of patients. Enzyme-Linked ImmunoSorbent Assay was used to measure serum brain-derived neurotrophic factor (BDNF) levels.

RESULTS

Among the patients taking clozapine and typical antipsychotic drugs, the RBANS total score, immediate memory, attention, and delayed memory subscores in females were higher than those in males (all p < 0.05). The RBANS total score and the delayed memory subscores in female patients taking risperidone were higher than those in male patients (all p < 0.05). Significant correlation between BDNF and cognition only existed in male patients taking clozapine, male patients taking risperidone, and male and female patients taking typical antipsychotic drugs (all p < 0.05).

CONCLUSION

Regardless of antipsychotic effect, the cognitive function of female patients is better compared to that of male patients. For male patients, the association between BDNF and cognitive performance exists in each medication group. For female patients, this significant association was only shown in the typical antipsychotic group, but not in the clozapine and risperidone groups.

Distinct association of plasma BDNF concentration and cognitive function in depressed patients treated with vortioxetine or escitalopram

RATIONALE

Cognitive dysfunction is frequent in major depressive disorder (MDD), and brain-derived neurotrophic factor (BDNF) is involved both in regulation of cognition and in therapeutic response in MDD.

OBJECTIVES

The aim of this study was to determine if baseline plasma BDNF might predict change in cognitive function in MDD patients treated with vortioxetine or escitalopram, and whether the alterations in BDNF levels correlate with changes in cognitive performance during treatment.

METHODS

Drug-naive or drug-free patients with MDD (N=121) were sampled and evaluated at baseline and 4 weeks after treatment initiation with vortioxetine or escitalopram. Cognitive function was evaluated using the F-A-S test, Digit Span test, and Digit Symbol Coding test. Plasma BDNF was determined using ELISA.

RESULTS

The results of the study indicate that both vortioxetine (V) and escitalopram (E) improved cognitive functions evaluated with F-A-S test (V: p<0.001; r=-0.427, E: p<0.001; r=-0.370), Digit Symbol Coding test (V: p<0.001; r=-0.706, E: p<0.001; r=-0.435), and Digit Span test-backward span (V: p=0.001; r=-0.311, E: p=0.042; r=-0.185), while only vortioxetine (p<0.001; r=-0.325) improved cognition evaluated with the Digit Span test-forward span. A moderate positive correlation between pretreatment plasma BDNF levels and improvement in cognitive performance was only detected in patients treated with vortioxetine (delta F-A-S test: p=0.011; r=0.325, delta Digit Span test-forward span: p=0.010, r=0.326).

CONCLUSIONS

These results suggest that higher baseline plasma BDNF levels might be associated with improvements in verbal fluency and working memory in vortioxetine, but not escitalopram treated patients. Vortioxetine treatment was superior in simple attention efficiency.

The use of recombinant tissue plasminogen activator in in acute ischemic stroke is associated with increased level of BDNF

Much concern was directed towards the crucial role of recombinant tissue plasminogen activator (rt-PA) in improving neuroplasticity in patients with acute ischemic stroke. The aim of the work to investigate the effect of treating patients with acute ischemic stroke with rt-PA, on the level of brain derived neurotrophic factor (BDNF) as a marker of neuroplasticity. This study was conducted on 47 patients presenting with acute ischemic stroke (during the first 4.5 h from stroke onset); 26 patients of them eligible for receiving rt-PA (patient group) and 21 patients having contraindications for treatment with rt-PA (control group). Neurological, radiological and laboratory assessment (including BDNF serum level) were done for both groups at stroke onset (before receiving rt-PA) and at day 7. There was a statistically significant increase in BDNF serum level from day 1 to day 7 in rt-PA treated patients in comparison to control group (P-value˂ 0.001). Serum level of BDNF is significantly higher at the onset of stroke in female patients and non-smokers than males or smokers (P-value = 0.011, 0.01 respectively). There was no effect of either age, body mass index, hypertension, diabetes, drug abuse, past or family history of stroke, valvular heart diseases, atrial fibrillation, cardiomyopathy, ejection fraction, carotid atherosclerotic changes, lipid profile or uric acid, on BDNF serum level measured at the onset of stroke. Treatment of patients with acute ischemic stroke with rt-PA causes significant improvement in neuroplasticity through increasing BDNF serum level.

Reinforcement of Self-Regulated Brain Activity in Schizophrenia Patients Undergoing Rehabilitation

The experiment was aimed to compare the effects of different forms of rehabilitation applied in patients with schizophrenia. Verification of the obtained results was based on the analysis of the level of cognitive and social functioning of the subjects. For this purpose, the following clinical tools were used: Positive and Negative Syndrome Scale (PANSS), Beck Cognitive Insight Scale (BCIS), Color Trial Test (CTT-1, CTT-2), d2 psychological tests, Acceptance of Illness Scale (AIS), Self-efficacy Scale (GSES), Quantitative Electroencephalogram Biofeedback (QEEG-BF), auditory event-related potentials (ERPs), and serum levels of brain-derived neurotrophic factor (BDNF). The subjects were mentally stable male schizophrenia patients who had been in remission. They were divided into two groups which received different types of rehabilitation for three months. Group 1 patients followed a standard rehabilitation and Group 2 patients received GSR Biofeedback (galvanic skin response Biofeedback, GSR-BF) training. Pretherapy and posttherapy measurements were made for each group. Experimental rehabilitation based on GSR-BF training resulted in regulatory control of neurophysiological mechanisms, and the parameters obtained demonstrated improvement in the subjects' cognitive and social function. The following therapy outcomes were observed: (1) reduce psychopathological symptoms (2) improving cognitive (concentration, attention) and social functions (3) increase in the neurotrophic factor BDNF. GSR-BF can be used as an alternative to conventional rehabilitation in schizophrenia patients.

Peripheral BDNF and psycho-behavioral aspects are positively modulated by high-intensity intermittent exercise and fitness in healthy women

Acute high-intensity intermittent exercise (HIIE) induces the myokine secretion associated with neurogenesis, as well brain-derived neurotrophic factor (BDNF); however, it remains unknown how the menstrual phase influences this secretion after an acute exercise session. The current study aimed to investigate the effects of HIIE performed in luteal and follicular menstrual phases on BDNF, cognitive function, mood, and exercise enjoyment. Fourteen healthy women completed four experimental sessions, randomly. One graded exercise test (GXT) and one HIIE session (10 × 1-min runs 90% peak GXT velocity [1-min recovery]) were performed for each menstrual phase. Blood samples were collected at rest and immediately after efforts, and the profile of mood states questionnaire (POMS) and Stroop-task test were applied. During the HIIE, subjective scales were applied (feeling, felt arousal, rate of perceived exertion, and physical activity enjoyment). The main results showed that the serum BDNF presented no difference between menstrual phases (p = 0.870); however, HIIE increased BDNF concentration in both menstrual phases (p = 0.030). In addition, the magnitude of circulating BDNF variation (Δ%BDNF) and [Formula: see text] demonstrated an inverse relationship in the follicular phase (r =  - 0.539, p = 0.046), whereas in the luteal phase, Δ%BDNF was negatively correlated with time test (r =  - 0.684, p = 0.007) and RPE (r =  - 0.726, p = 0.004) in GXT. No differences between menstrual phases were observed for POMS (p ≥ 0.05); however, HIIE attenuated tension (p < 0.01), depression (p < 0.01), and anger moods (p < 0.01), independently of menstrual phases. The subjective scales and Stroop-task test did not show differences. In conclusion, menstrual cycle phase does not affect serum BDNF levels, cognitive function, mood, and exercise enjoyment. Contrary, HIIE increases peripheral BDNF and attenuates tension, depression, and anger independently of menstrual phase. In addition, Δ%BDNF was correlated with physical fitness in the follicular phase, exhibiting higher changes in women with lower physical fitness status.

Cerebral Hemodynamic and Neurotrophic Factor Responses Are Dependent on the Type of Exercise

This study examined acute cerebral hemodynamic and circulating neurotrophic factor responses to moderate intensity continuous exercise (MICT), guideline-based high intensity interval exercise (HIIT), and sprint interval exercise (SIT). We hypothesized that the pattern of middle cerebral artery velocity (MCAv) response would differ between interval and continuous exercise, with SIT inducing the smallest increase from rest, while increases in neurotrophic factors would be intensity-dependent. In a randomized crossover design, 24 healthy adults (nine females) performed three exercise protocols: (i) MICT (30 min), (ii) HIIT (4 × 4 min at 85% HRmax), and (iii) SIT (4 × 30 s supramaximal). MCAv significantly increased from rest across MICT (Δ13.1 ± 8.5 cm⋅s-1, p < 0.001) and all bouts of HIIT (Δ15.2 ± 9.8 cm⋅s-1, p < 0.001), but only for the initial bout of SIT (Δ17.3 ± 11.6 cm⋅s-1, p < 0.001). Immediately following each interval bout, MCAv increased (i.e., rebounded) for the SIT (9-14% above rest, p ≤ 0.04), but not HIIT protocol. SIT alone induced significant elevations from rest to end-exercise in vascular endothelial growth factor (VEGF; Δ28 ± 36%, p = 0.017) and brain-derived neurotrophic factor (BDNF, Δ149% ± 162%, p < 0.001) and there were greater increases in lactate than in either other protocol (>5-fold greater in SIT, p < 0.001), alongside a small significant reduction at the end of active recovery in insulin-like growth factor 1 (IGF-1, Δ22 ± 21%, p = 0.002). In conclusion, while the nature of the response may differ, both guideline-based and sprint-based interval exercise have the potential to induce significant changes in factors linked to improved cerebrovascular and brain health.

Roles of miR-10a-5p and miR-103a-3p, Regulators of BDNF Expression in Follicular Fluid, in the Outcomes of IVF-ET

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, plays critical roles in the physiological process of oocyte mature and IVF outcomes of patients with infertility. However, the regulation of BDNF expression in the microenvironment surrounding the oocyte is still unknown. We initially predicted some microRNA (miRNA) candidates targeting bdnf with a series of bioinformatics analysis tools to determine the underlying regulatory mechanisms of BDNF, particularly the effect of miRNAs on BDNF expression. Then, we assessed whether the expression of these 14 selected miRNAs was negatively associated with BDNF expression in follicular fluid (FF) samples obtained from mature (>18 mm) or immature (<15 mm) follicles. Finally, we used the candidate miRNAs, miR-103a-3p and miR-10a-5p, to further investigate the relationship between their expression in FF and the outcomes of infertile patients undergoing IVF-ET treatment. The results of the bioinformatics analysis revealed 14 miRNAs that might directly regulate BDNF expression and might have a close relationship with oocyte development. BDNF was expressed at significantly lower levels in FF from immature follicles than in FF from mature follicles, and only the expression of miR-103a-3p and miR-10a-5p was negatively correlated with BDNF expression in FF. Moreover, in another cohort of 106 infertile women undergoing IVF-ET treatment, miR-103a-3p or miR-10a-5p expression predicted the developmental status of the corresponding oocytes in which high expression of miR-103a-3p or miR-10a-5p resulted in a poor quality of embryo on days 3 and 5 during the IVF-ET treatment. In conclusion, our study is the first to show that miR-103a-3p or miR-10a-5p negatively affects the maturation of oocytes by regulating the expression of BDNF in human FF. Additionally, the expression levels of miR-103a-3p or miR-10a-5p in FF may predict the outcomes of IVF, which are helpful for improving embryo selection and consequently the IVF success rate in the clinic.

Effects of the BDNF Val66Met polymorphism on functional status and disability in young stroke patients

BACKGROUND AND PURPOSE

The preponderance of evidence from recent studies in human subjects supports a negative effect of the BDNF Val66Met polymorphism on motor outcomes and motor recovery. However prior studies have generally reported the effect of the Met allele in older stroke patients, while potential effects in younger stroke patients have remained essentially unexamined. The lack of research in younger patients is significant since aging effects on CNS repair and functional recovery after stroke are known to interact with the effects of genetic polymorphisms. Here we present a study of first-ever ischemic stroke patients aged 15-49 years that examines the effect of Met carrier status on functional disability.

METHODS

829 patients with a first ischemic stroke (Average age = 41.4 years, SD = 6.9) were recruited from the Baltimore-Washington region. Genotyping was performed at the Johns Hopkins University Center for Inherited Disease Research (CIDR). Data cleaning and harmonization were done at the GEI-funded GENEVA Coordinating Center at the University of Washington. Our sample contained 165 Met carriers and 664 non-Met carriers. Modified Rankin scores as recorded at discharge were obtained from the hospital records by study personnel blinded to genotype, and binarized into "Good" versus "Poor" outcomes (mRS 0-2 vs. 3+), with mRS scores 3+ reflecting a degree of disability that causes loss of independence.

RESULTS

Our analysis showed that the Met allele conveyed a proportionally greater risk for poor outcomes and disability-related loss of independence with mRS scores 3+ (adjusted OR 1.73, 95% CI 1.13-2.64, p = 0.01).

CONCLUSIONS

The BDNF Val66Met polymorphism was negatively associated with functional outcomes at discharge in our sample of 829 young stroke patients. This finding stands in contrast to what would be predicted under the tenets of the resource modulation hypothesis (i.e. that younger patients would be spared from the negative effect of the Met allele on recovery since it is posited to arise as a manifestation of age-related decline in physiologic resources).

Brain-derived neurotrophic factor (BDNF) expression and function in the mammalian reproductive Tract

BACKGROUND

Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central nervous system. A growing body of literature shows that neurotrophins and their receptors are also expressed throughout the reproductive tract.

OBJECTIVE AND RATIONALE

Neurotrophins are key regulatory proteins in reproductive physiology during development and throughout adult life. Of the neurotrophins, the literature describing the expression and function of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, neurotrophin receptor kinase-2 (NTRK2), has been expanding rapidly. We therefore conducted a systematic inductive qualitative review of the literature to better define the role of the BDNF in the reproductive tract. We postulate that BDNF and NTRK2 are central regulatory proteins throughout the reproductive system.

SEARCH METHODS

An electronic search of Medline (PubMed) and Web of Science for articles relating to BDNF and the reproductive system was carried out between January 2018 and February 2019.

OUTCOMES

In the ovary, BDNF expression and levels have been linked with follicle organisation during ovarian development, follicle recruitment and growth and oocyte maturation. In the endometrium, BDNF is involved in cell proliferation and neurogenesis. In contrast, literature describing the role of BDNF in other reproductive tissues is sparse and BDNF-NTRK2 signalling in the male reproductive tract has been largely overlooked. Whilst estradiol appears to be the primary regulator of BDNF expression, we also identified reports describing binding sites for glucocorticoid and myocyte enhancer factor-2, a calcium-response element through activation of an N-methyl-D-aspartate (NMDA) receptor, and aryl hydrocarbon receptor nuclear transporter protein-4 (ARNT) response elements in promoter regions of the BDNF gene. Expression is also regulated by multiple microRNAs and post-translational processing of precursor proteins and intracellular shuttling. BDNF-NTRK2 signalling is modulated through tissue specific receptor expression of either the full-length or truncated NTRK2 receptor; however, the functional importance remains to be elucidated. Dysregulation of BDNF expression and circulating concentrations have been implicated in several reproductive disorders including premature ovarian failure, endometriosis, pre-eclampsia, intra-uterine growth restriction (IUGR) and several reproductive cancers.

WIDER IMPLICATIONS

We conclude that BDNF and its receptors are key regulatory proteins central to gonadal development, ovarian regulation and uterine physiology, as well as embryo and placenta development. Furthermore, dysregulation of BDNF-NTRK2 in reproductive diseases suggests their potential role as candidate clinical markers of disease and potential therapeutic targets.

Brain-derived neurotrophic factor is related to stress and chewing in saliva and salivary glands

Chewing is one of the most important orofacial functions. During this process, food is reduced in size, while saliva moistens the food and binds it into a bolus that can be easily swallowed. Characteristics of the oral system, including the number of teeth, bite force, and salivary flow, influence the masticatory process. In addition, salivary glands produce several cell growth factors and play an important role in human health. The nerve growth factor (NGF) family consists of NGF, brain-derived neurotrophic factor (BDNF), and neurotrophins-3 to 7. BDNF is a well-studied neurotrophin involved in the neurogenesis, differentiation, and maintenance of select peripheral and central neuronal cell populations during development and adulthood. However, there has been no detailed description of the expression of neurotrophins other than NGF in the salivary gland. We previously studied the effect of immobilization stress + chewing on BDNF secretion and its receptor, tyrosine receptor kinase B, in rat submandibular glands and found increased BDNF expression in duct cells under these conditions. In this review, we describe recent advances in understanding the role of stress and chewing-related BDNF in the saliva and salivary glands.

Beyond Haemostasis and Thrombosis: Platelets in Depression and Its Co-Morbidities

Alongside their function in primary haemostasis and thrombo-inflammation, platelets are increasingly considered a bridge between mental, immunological and coagulation-related disorders. This review focuses on the link between platelets and the pathophysiology of major depressive disorder (MDD) and its most frequent comorbidities. Platelet- and neuron-shared proteins involved in MDD are functionally described. Platelet-related studies performed in the context of MDD, cardiovascular disease, and major neurodegenerative, neuropsychiatric and neurodevelopmental disorders are transversally presented from an epidemiological, genetic and functional point of view. To provide a complete scenario, we report the analysis of original data on the epidemiological link between platelets and depression symptoms suggesting moderating and interactive effects of sex on this association. Epidemiological and genetic studies discussed suggest that blood platelets might also be relevant biomarkers of MDD prediction and occurrence in the context of MDD comorbidities. Finally, this review has the ambition to formulate some directives and perspectives for future research on this topic.