Plasma brain-derived neurotrophic factor in hemodialysis patients

Plasma brain-derived neurotrophic factor before hemodialysis reduces the risk of depression in patients with chronic renal failure

BACKGROUND

Neurotrophins are related with depressive disorders. Significant neurotrophins variations occur during renal replacement therapy, but whether peri-hemodialysis availability is associated with depression in patients with Chronic Kidney Disease (CKD) is yet unclear.

AIM

To determine dynamic concentrations of neurotrophins in the peri-hemodialysis range and their association with depressive symptoms in patients with CKD.

METHODS

Pre-, and post-hemodialysis plasma concentrations of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), as well as their plasma clearance rates, were determined (multiplexing) in patients with stage 5 CKD. Depressive symptoms, as assessed by the Beck Depression Inventory-II (BDI-II), were determined. Finally, the bioavailability of BDNF and NGF was related to the score of depressive symptoms.

RESULTS

Fifty-three patients were divided according to depressive symptoms. Pre-hemodialysis plasma BDNF was lower in patients with depressive disorder; whereas basal BDNF value >220 pg/mL independently reduced the risk for depressive disorder (Odds Ratio 0.23, p = 0.047) at uni- and multivariate analysis. Post-hemodialysis concentration and clearance rate of neurotrophins were not related with depressive symptoms.

CONCLUSION

Higher plasma BDNF before hemodialysis reduces the risk of mild depression in patients with CKD under renal replacement therapy.

Assessment of brain-derived neurotrophic factor and irisin concentration in children with chronic kidney disease: a pilot study

Patients suffering from chronic kidney disease (CKD) are particularly placed at risk of multiorgan complications. One of them is malnutrition, which adds up to a higher mortality factor among them. This study was designed to determine the usefulness of brain-derived neurotrophic factor (BDNF) and irisin assays in the assessment of CKD development. The study group included 28 children with CKD at stages 2-5 treated conservatively. The outcome of our study revealed decreased serum BDNF and irisin levels in CKD patients, whereas urine concentrations were increased for BDNF and decreased for irisin, comparing to healthy controls. There was a positive correlation between anthropometric measures and urine BDNF concentration, as well as anthropometric measures and both serum and urine irisin levels in the study group, however no dependence of the tested markers on the stage of CKD was observed. In recent years, a role of myokines was described as vital for maintaining metabolic homeostasis therefore we suspect a potential role of these multifaceted markers in detecting malnutrition in CKD children.

Evaluation of the relationship between serum BDNF concentration and indicators of oxidative stress and inflammation in COVID-19 patients with neurological disorders - a pilot study

INTRODUCTION

The aim of this study was to determine the effect of serum level of brain-derived neurotrophic factor (BDNF) on the development of neurological disorders in COVID-19 patients and the probable role of oxidative stress and inflammation in this phenomenon.

METHODS

The present case-control study included 42 COVID-19 patients referring to Golestan and Sina hospitals of Ahvaz, Iran, for treatment. Patients with (n = 18) and without (n = 24) neurological disorders were allocated into test and control groups, respectively. Following blood sampling, serum isolation was done, and the serum was stored at -80°C until biochemical assessment for measuring BDNF, oxidative stress indices, and inflammatory factors.

RESULTS

Although no significant brain damage was observed in the COVID-19 patients with neurological disorders, the results showed that the serum level of BDNF in the test group increased compared to that in the control group, and this increment was accompanied with increased Tumor Necrosis Factor-alpha (TNF-α) and decreased Interferon gamma (IFN-γ) levels in the serum. Moreover, compared to the control group, patients in the test group had a decreased level of Thiol and an increased level of Malondialdehyde (MDA) in the serum. Furthermore, there was a significant positive correlation between the serum concentration of BDNF and nitric oxide (NO) in the test group.

CONCLUSION

Using over-the-counter (OTC) medicines which include thiol-group-related agents or any other antioxidants can alleviate oxidative stress and the associated increased inflammation in COVID-19 patients with neurological symptoms.

Neurotrophin-4 and Brain-Derived Neurotrophic Factor Serum Levels in Renal Transplant Recipients with Chronic Pruritus

INTRODUCTION

Chronic pruritus (CP) is a common symptom defined as a sensation that provokes the desire to scratch and which lasts for at least 6 weeks. CP remains a problem for up to 21.3% of renal transplant recipients (RTRs). Our research aimed to establish the possible association between serum levels of neurotrophin-4 (NT-4) and brain-derived neurotrophic factor (BDNF) and the presence and intensity of CP in RTR.

METHODS

The study was performed on a group of 129 RTRs, who were divided according to the presence or absence of pruritus in the previous 3 days. The assessment of pruritus was performed with the use of a numeric rating scale (NRS), 4-Item Itch Questionnaire (4IIQ), and Itchy Quality of Life (Itchy QoL). A total of 129 blood samples with a volume of 9 ml were drawn from RTRs during the monthly routine control. Serum levels (pg/mL) of NT-4 and BDNF were measured by the ELISA.

RESULTS

Pruritic RTRs have statistically significantly higher serum concentrations of NT-4 serum level compared to non-pruritic RTRs (229.17 ± 143.86 pg/mL and 153.08 ± 78.19 pg/mL [p = 0.024], respectively). Moreover, a statistically significant difference between pruritic and non-pruritic RTRs with healthy controls was shown (p < 0.001 and p < 0.001, respectively). Although there was a numerically higher serum concentration of BDNF in pruritic RTRs (32.18 ± 7.31 pg/mL vs. 31.58 ± 10.84 pg/mL), the difference did not reach statistical significance. No statistically significant difference was also seen in BDNF serum levels between RTRs and healthy controls. Furthermore, there was a statistically significant, positive correlation between serum concentration of NT-4 and NRS score (p = 0.008, r = 0.357).

CONCLUSIONS

The results indicate higher NT-4 serum concentration in RTRs with pruritus compared to RTRs without pruritus. Furthermore, the study revealed a statistically significant, positive correlation between the serum concentration of NT-4 and NRS score.

Effect on nutritional status and biomarkers of inflammation and oxidation of an oral nutritional supplement (with or without probiotics) in malnourished hemodialysis patients. A multicenter randomized clinical trial "Renacare Trial"

BACKGROUND

Malnutrition in patients undergoing hemodialysis is frequent and associated with a reduction in muscular mass and strength, with an increment in biomarkers of inflammation and oxidation.

MATERIALS AND METHODS

Randomized, multicenter, parallel-group trial in malnourished hemodialysis patients with three groups [(1) control (C) individualized diet, (2) oral nutritional supplement-ONS- + placebo-SU- PL-, and (3) ONS + probiotics-SU-PR]; the trial was open regarding the intake of ONS or individualized diet recommendations, but double-blind for the intake of probiotics. We obtained, at baseline and after 3 and 6 months, anthropometric measurements, handgrip strength, bioelectrical impedance analysis (BIA), dietary records, and routine biochemical parameters. Inflammation and oxidation were determined using ELISA techniques (Versamax and ProcartaPlex multiplex Immunoassay). Results were analyzed by intention to treat.

RESULTS

A total of 31 patients (11 corresponding to group C, 10 to SU-PL, and 10 to SU-PR) completed the 6-months trial. The two groups that took supplements significantly increased their protein calorie, fat (total and n-3), and fiber intake. Weight and fat-free mass (FFM) also increased significantly in the groups on supplements, both at 3 and 6 months, and dynamometry did so in the SU-PL group. At month 3, prealbumin and vitamin D were significantly increased in the SU-TOT (SU-PL + SU-PR) group. No changes were observed regarding levels of phosphorus and potassium in any of the groups. Urea increased significantly at 6 months in the SU-PL group. There were significant changes in some inflammation biomarkers in the groups on supplements during the intervention (brain-derived neurotrophic factor, bone morphogenetic protein-2, MCP-1, IL-1-beta, IL-10, IL-4, and IL-8). The total antioxidant capacity (TAC) increased significantly in the supplemented patients, with no significant changes observed in isoprostanes.

CONCLUSION

The specific ONS improved protein-calorie intake, nutritional status (mainly FFM), and some biomarkers of inflammation/oxidation. The addition of probiotics could have a synergistic effect with ONS in such biomarkers.

CLINICAL TRAIL REGISTRATION

https://clinicaltrials.gov/ct2/show/, identifier NCT03924089.

The Function of BDNF and Its Receptor in the Male Genitourinary System and Its Potential Clinical Application

Background: Brain-derived neurotrophic factor (BDNF), as a member of the nerve growth factor family, has been mentioned more and more frequently in recent literature reports. Among them, content about the male genitourinary system is also increasing. Objective and Rationale: BDNF plays an important role in the male genitourinary system. At the same time, the literature in this field is constantly increasing. Therefore, we systematically summarized the literature in order to more intuitively show the function of BDNF and its receptor in the male genitourinary system and its potential clinical application. Search Methods: An electronic search of, e.g., PubMed, scholar.google and Scopus, for articles relating to BDNF and its receptor in the male genitourinary system. Outcomes: In the male genitourinary system, BDNF and its receptors TrkB and p75 participate in a series of normal physiological activities, such as the maturation and morphogenesis of testes and epididymis and maintenance of isolated sperm motility. Similarly, an imbalance of the circulating concentration of BDNF also mediates the pathophysiological process of many diseases, such as prostate cancer, benign prostatic hyperplasia, male infertility, diabetes erectile dysfunction, penile sclerosis, and bladder fibrosis. As a consequence, we conclude that BDNF and its receptor are key regulatory proteins in the male genitourinary system, which can be used as potential therapeutic targets and markers for disease diagnosis.

Elevated Level of Serum Neurotrophin-4, but Not of Brain-Derived Neurotrophic Factor, in Patients with Chronic Kidney Disease-Associated Pruritus

Chronic kidney disease-associated pruritus (CKD-aP) is a bothersome condition that occurs in patients with advanced chronic kidney disease (CKD) and severely reduces their quality of life. Recently, much research has focused on the search for markers that are involved in the pathogenesis of CKD-aP and may become a therapeutic target. One of the suggested hypotheses is the increased activation of sensory neurons by molecules such as neurotrophins (NTs). An increased serum concentration of NTs has been demonstrated in pruritic patients, which may suggest their involvement in the pathogenesis of itch. The purpose of this study is to assess the serum concentration of neurotrophin-4 (NT-4) and brain-derived neurotrophic factor (BDNF) in hemodialysis patients. The study enrolled 126 patients undergoing dialysis. Participants were divided into 2 groups: with and without CKD-aP. NRS scale was used to evaluate itch severity. Serum levels of NT-4 and BDNF have been assessed using ELISA. The results showed a significantly higher level of NT-4 in the group with pruritus. No significant difference was reported in the serum level of BDNF between the two groups of patients. There was also no correlation between serum NT-4 nor BDNF levels and the severity of pruritus. In summary, NT-4 may play an important role in the pathophysiology of pruritus in dialysis patients. More research is needed to understand the exact mechanism by which NTs influence the pathogenesis of CKD-aP.

Blood-brain barrier and gut barrier dysfunction in chronic kidney disease with a focus on circulating biomarkers and tight junction proteins

Kidney failure and associated uraemia have implications for the cardiovascular system, brain, and blood–brain barrier (BBB). We aim to examine BBB disruption, by assessing brain-derived neurotropic factor (BDNF), neuron-specific enolase (NSE) levels, and gut-blood barrier (GBB) disruption by trimethylamine N-oxide (TMAO), in chronic kidney disease (CKD) patients. Additionally, endothelial tight-junction protein expressions and modulation via TMAO were assessed. Serum from chronic kidney disease (CKD) female and male haemodialysis (HD) patients, and controls, were used to measure BDNF and NSE by enzyme-linked immunosorbent assays, and TMAO by mass spectrometry. Immunofluorescent staining of subcutaneous fat biopsies from kidney transplant recipients, and controls, were used to measure microvascular expression of tight-junction proteins (claudin-5, occludin, JAM-1), and control microvasculature for TMAO effects. HD patients versus controls, had significantly lower and higher serum levels of BDNF and NSE, respectively. In CKD biopsies versus controls, reduced expression of claudin-5, occludin, and JAM-1 were observed. Incubation with TMAO significantly decreased expression of all tight-junction proteins in the microvasculature. Uraemia affects BBB and GBB resulting in altered levels of circulating NSE, BDNF and TMAO, respectively, and it also reduces expression of tight-junction proteins that confer BBB maintenance. TMAO serves as a potential candidate to alter BBB integrity in CKD.

Evaluation of serum levels of neurotrophin 4 and brain-derived nerve growth factor in uremic pruritus patients

Background

Pruritus is a common symptom in end-stage renal failure. Many patients suffer from this severe distressing symptom. Although several factors have been postulated to explain uremic pruritus, there is not any conclusive evidence for one of these factors.

Objectives

We aimed to evaluate serum levels of brain-derived nerve growth factor (BDNF), neurotrophin-4 (NT-4), serum calcium, phosphors and parathyroid hormone in uremic patients with pruritus and without pruritus compared to control subjects.

Methods

One hundred twenty patients suffering from renal failure and 60 healthy subjects were included in the study. Serum BDNF and NT4 levels were determined by ELISA. The serum calcium, phosphorus, parathyroid hormone and hemoglobin were also evaluated.

Results

Serum BDNF was significantly higher in uremic patients with pruritus (P=0.0026) and uremic patients without pruritus (P=0.0294) than control subjects. In addition, NT-4 levels were significantly elevated in uremic patients with pruritus (P<0.0001) and uremic patients without pruritus than control subjects (P=0.0016). There was no significant difference of serum level of BDNF between uremic patients with pruritus and uremic patients without pruritus (P=0.1215). However, serum NT-4 was higher in uremic patients with pruritus vs nonpruritic uremic patients with a significant difference (P=0.0026). There was a positive significant correlation between serum level of NT-4 and severity of pruritus (P=0.024).

Conclusion

The present study shows that NT-4 level is increased in the serum of uremic patients with pruritus and there was a significant correlation between NT-4 and severity of pruritus suggesting that NT-4 may have a role in uremic pruritus.

Effect of a high sucrose and high fat diet in BDNF (+/-) mice on oxidative stress markers in adipose tissues

The purpose of this study was to investigate the effects of a high fat and a high sucrosediet in wild type and BDNF (+/-) mice on oxidative stress in epididymal and subcutaneousadipose tissues by measuring different markers of oxidative stress and antioxidant enzymes. Wild type (WT) and BDNF (+/-) male mice were divided into six groups receiving fed control diet (CD), high sucrose diet (HSD), or high fat diet (HFD) for four months. Levels of 3-nitrotyrosine (3-NT) increased in the HFD-fed BDNF (+/-) mice, while 4-hydroxynonenal (4-HNE) levels increased in the CD and HFD-fed BDNF (+/-) groups. Malondialdehyde (MDA) levels decreased in subcutaneous tissue compared to epididymal adipose tissue, independently of diet type. Superoxide dismutase (SOD) activity was reduced by HFD (p < 0.05), butglutathione peroxidase (GSH-Px) activity was increased by HSD in epididymal adipose tissuein BDNF (+/-) mice (p < 0.05). GSH-Px activities was increased by CD and HFD in subcutaneous adipose tissue of BDNF (+/-) (p < 0.05). SOD2 and GSH-Px3 expressions were only decreased by HSD in epididymal and subcutaneous adipose tissues of BDNF (+/-) mice (p < 0.05). In conclusion, reduced BDNF may increase OS in epididymal adipose tissue, but not in subcutaneous adipose tissue following HSD and HFD.

The impact of plasma brain-derived neurotrophic factor concentration and weight gain after kidney transplantation

Obesity and its related complications continue to be significant challenges for kidney transplant recipients. In previous studies, researchers have reported that brain-derived neurotrophic factor (BDNF) is closely associated with metabolic imbalance and obesity, but the role of BDNF in weight gain after kidney transplant has not been elucidated. The purpose of this pilot study was to explore the relationship between plasma BDNF levels and weight change. We examined associations between plasma BDNF levels measured at transplantation and 12 months later and measures of weight change during these 12 months in a sample of 55 kidney recipients (mean age of 48 years, 60% male, 56% African American). Of the 55 recipients, 49 had BDNF levels measured at baseline, 33 had BDNF levels measured at 12 months, and 27 had BDNF levels measured at both time points. We found that plasma BDNF levels at baseline (n = 49), but not at 12 months (n = 33), were significantly and positively correlated with the body mass index change (p = 0.037) and percentage weight change (p = 0.036). In addition, average plasma BDNF value at 12 months (307 ± 254 pg/ml) was significantly lower than at baseline (452 ± 345 pg/ml) in the 27 recipients with BDNF levels measured at both time points. Findings from this pilot work suggest that BDNF might serve as a regulator of weight change for kidney transplant related obesity.

Differential expression of serum biomarkers in hemodialysis patients with mild cognitive decline: A prospective single-center cohort study

Studies suggest that hemodialysis patients are at a higher risk for cognitive decline than healthy individuals; however, underlying mechanisms have not been fully elucidated. We aimed to investigate the roles of serum biomarkers, such as brain-derived neurotrophic factor (BDNF), inflammatory cytokines, fibroblast growth factor (FGF)-23 and its co-receptor α-klotho and platelet (PLT) count in mild cognitive decline (MCD) of patients undergoing hemodialysis in this prospective cohort study. Serum levels of BDNF, tumour necrosis factor (TNF)-α, interleukin (IL)-6 and the number of PLT were significantly altered in the MCD group compared with those in healthy controls (HCs) or those with normal cognitive function (NCF). Although serum α-klotho and FGF-23 levels were significantly altered in the MCD group, there were no statistical differences between the MCD and NCF groups. Serum BDNF levels and PLT counts were significantly correlated with cognitive test scores. Receiver operating characteristic (ROC) curves demonstrated that BDNF and PLT were potential biomarkers for improved MCD diagnosis in patients with hemodialysis. These findings suggest that hemodialysis-related MCD is associated with altered BDNF, TNF-α and IL-6 levels as well as PLT counts and that serum BDNF levels and PLT counts are potential biomarkers for hemodialysis-related MCD diagnosis.

Association of brain-derived neurotrophic factor and interleukin-6 serum levels with depressive and anxiety symptoms in hemodialysis patients

OBJECTIVE

This study assessed the possible association of serum brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) with depressive and anxiety symptoms in hemodialysis (HD) patients.

METHOD

An analytical cross-sectional study was conducted over 274 HD patients from March to October 2017. The Hospital Anxiety and Depression Scale (HADS) was utilized to evaluate depressive (HADS-D) and anxiety (HADS-A) symptoms. The HADS-D/A is a self-report instrument that has a maximum score of 21. Serum BDNF and IL-6 were measured using enzyme-linked immunosorbant assay (ELISA).

RESULTS

Serum IL-6 was significantly higher in patients with depressive symptoms compared to normal (20.47 ± 4.27 pg/mL for HADS-D ≥11 versus 9.26 ± 1.59 pg/mL for HADS-D <7, p = 0.014). Multivariable regression analysis revealed that IL-6, education level, hypertension, and dialysis duration were significant predictors of HADS-D. Also, gender, education level, hypertension, and the number of dialysis sessions/week were significant predictors of HADS-A. Significant positive correlation was shown between HADS-D and IL-6 (r = 0.1729, p = 0.004).

CONCLUSION

Collectively, HD patients with depressive symptoms showed higher levels of IL-6, supporting previous findings that the circulating inflammatory mediator IL-6 can be used as a biomarker for prediction of depressive symptoms in HD patients. Further longitudinal or interventional studies are needed to further validate this association.

Brain-derived neurotrophic factor is increased in serum levels of patients with symptomatic dermographism

Introduction

Symptomatic dermographism (SD) is the most common form of physical urticaria. However, the role of neuroimmune mechanisms in SD is unclear.

Aim

To investigate circulating levels of brain-derived neurotrophic factor (BDNF) in symptomatic dermographism.

Material and methods

Thirty-two patients suffering from SD and 33 healthy subjects were included in the study. Serum BDNF levels were determined by a human enzyme-linked immunoassay (ELISA) kit. The serum C-reactive protein concentration and eosinophil counts in peripheral blood were evaluated.

Results

The BDNF serum levels were detectable in both SD patients and healthy controls. The BDNF serum levels were significantly higher in patients with SD compared with healthy controls (p = 0.004). There was a positive but weak correlation between serum BDNF and CRP levels; it was not statistically significant (r = 0.211, p = 0.255). There was also a positive but weak correlation between serum BDNF and eosinophil counts; it was not statistically significant (r = 0.271, p = 0.141).

Conclusions

The present study shows that BDNF is increased in the serum levels of patients with SD, suggesting a role for BDNF in the pathophysiology of this disorder.

Measuring myokines with cardiovascular functions: pre-analytical variables affecting the analytical output

In the last few years, a growing number of molecules have been associated to an endocrine function of the skeletal muscle. Circulating myokine levels, in turn, have been associated with several pathophysiological conditions including the cardiovascular ones. However, data from different studies are often not completely comparable or even discordant. This would be due, at least in part, to the whole set of situations related to the preparation of the patient prior to blood sampling, blood sampling procedure, processing and/or store. This entire process constitutes the pre-analytical phase. The importance of the pre-analytical phase is often not considered. However, in routine diagnostics, the 70% of the errors are in this phase. Moreover, errors during the pre-analytical phase are carried over in the analytical phase and affects the final output. In research, for example, when samples are collected over a long time and by different laboratories, a standardized procedure for sample collecting and the correct procedure for sample storage are acknowledged. In this review, we discuss the pre-analytical variables potentially affecting the measurement of myokines with cardiovascular functions.

The positive cognitive impact of aerobic fitness is associated with peripheral inflammatory and brain-derived neurotrophic biomarkers in young adults

There is ample evidence for supporting the positive impact of aerobic fitness on cognitive function, but little is known about the physiological mechanisms. The objective of this study was to investigate whether the positive cognitive impact of aerobic fitness is associated with inflammatory and neurotrophic peripheral biomarkers in young adults aged 18 to 29years (n=87). For the objective assessment of aerobic fitness, we measured maximal oxygen uptake (VO₂max) as a parametric measure of cardiorespiratory capacity. We demonstrated that young adults with the higher levels of VO₂max performed better on computerized cognitive tasks assessing sustained attention and working memory. This positive VO₂max-cognitive performance association existed independently of confounders (e.g., years of education, intelligence scores) but was significantly dependent on resting peripheral blood levels of inflammatory (C-reactive protein, CRP) and neurotrophic (brain-derived neurotrophic factor, BDNF) biomarkers. Statistical models showed that CRP was a mediator of the effect of VO₂max on working memory. Further, BDNF was a moderator of the effect of VO₂max on working memory. These mediating and moderating effects occurred in individuals with higher levels of aerobic fitness. The results suggest that higher aerobic fitness, as measured by VO₂max, is associated with enhanced cognitive functioning and favorable resting peripheral levels of inflammatory and brain-derived neurotrophic biomarkers in young adults.

Antidiabetic Effect of Brain-Derived Neurotrophic Factor and Its Association with Inflammation in Type 2 Diabetes Mellitus

Brain-derived neurotrophic factor (BDNF) is a neurotrophin, which plays an important role in the central nervous system, and systemic or peripheral inflammatory conditions, such as acute coronary syndrome and type 2 diabetes mellitus (T2DM). BDNF is also expressed in several nonneuronal tissues, and platelets are the major source of peripheral BDNF. Here, we reviewed the potential role of BDNF in platelet reactivity in T2DM and its association with selected inflammatory and platelet activation mediators. Besides that, we focused on adipocytokines such as leptin, resistin, and adiponectin which are considered to take part in inflammation and both lipid and glucose metabolism in diabetic patients as previous studies showed the relation between adipocytokines and BDNF. We also reviewed the evidences of the antidiabetic effect of BDNF and the association with circulating inflammatory cytokines in T2DM.

Neurotrophins and cognitive functions in T1D compared with healthy controls: effects of a high-intensity exercise

Exercise is known to have beneficial effects on cognitive function. This effect is greatly favored by an exercise-induced increase in neurotrophic factors, such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1), especially with high-intensity exercises (HIE). As a complication of type 1 diabetes (T1D), a cognitive decline may occur, mostly ascribed to hypoglycaemia and chronic hyperglycaemia. Therefore, the purpose of this study was to examine the effects of acute HIE on cognitive function and neurotrophins in T1D and matched controls. Ten trained T1D (8 males, 2 females) participants and their matched (by age, sex, fitness level) controls were evaluated on 2 occasions after familiarization: a maximal test to exhaustion and an HIE bout (10 intervals of 60 s at 90% of their maximal wattage followed by 60 s at 50 W). Cognitive tests and analyses of serum BDNF, IGF-1, and free insulin were performed before and after HIE and following 30 min of recovery. At baseline, cognitive performance was better in the controls compared with the T1D participants (p < 0.05). After exercise, no significant differences in cognitive performance were detected. BDNF levels were significantly higher and IGF-1 levels were significantly lower in T1D compared with the control group (p < 0.05) at all time points. Exercise increased BDNF and IGF-1 levels in a comparable percentage in both groups (p < 0.05). In conclusion, although resting levels of serum BDNF and IGF-1 were altered by T1D, comparable increasing effects on BDNF and IGF-1 in T1D and healthy participants were found. Therefore, regularly repeating acute HIE could be a promising strategy for brain health in T1D.

Serum Brain-Derived Neurotrophic Factor is Related to Platelet Reactivity but not to Genetic Polymorphisms within BDNF Encoding Gene in Patients with Type 2 Diabetes

Background

The aim of this study was to investigate the association between serum concentrations of the brain-derived neurotrophic factor (BDNF), platelet reactivity and inflammatory markers, as well as its association with BDNF encoding gene variants in type 2 diabetic patients (T2DM) during acetylsalicylic acid (ASA) therapy.

Material/Methods

This retrospective, open-label study enrolled 91 patients. Serum BDNF, genotype variants, hematological, biochemical, and inflammatory markers were measured. Blood samples were taken in the morning 2–3 h after the last ASA dose. The BDNF genotypes for selected variants were analyzed by use of the iPLEX Sequenom assay.

Results

In multivariate linear regression analysis, CADP-CT >74 sec (p<0.001) and sP-selectin concentration (p=0.03) were predictive of high serum BDNF. In multivariate logistic regression analysis, CADP-CT >74 sec (p=0.02) and IL-6 concentration (p=0.03) were risk factors for serum BDNF above the median. Non-significant differences were observed between intronic SNP rs925946, missense SNP rs6265, and intronic SNP rs4923463 allelic groups and BDNF concentrations in the investigated cohort.

Conclusions

Chronic inflammatory condition and enhanced immune system are associated with the production of BDNF, which may be why the serum BDNF level in T2DM patients with high platelet reactivity was higher compared to subjects with normal platelet reactivity in this study.

The relationship between brain-derived neurotrophic factor levels, oxidative and nitrosative stress and depressive symptoms: a study on peritoneal dialysis

BACKGROUND

Depression is one of the most commonly encountered psychiatric problems in peritoneal dialysis (PD) patients. Our aim was to investigate the associations between oxidative and nitrosative stress (O&NS) and brain-derived neurotrophic factor (BDNF) in PD patients with elevated depressive symptoms (EDS).

METHODS

Eighty-three patients with PD and 84 healthy controls were enrolled in this study. In PD patients, two subgroups were formed: 28 with and 55 without EDS. EDS were defined as a Beck Depression Inventory (BDI) score ≥17 in patients. Serum malondialdehyde (MDA) erythrocyte, glutathione (GSH) levels measured spectrophotometrically. Serum superoxide dismutase (SOD) activity, nitric oxide (NO) and BDNF levels were determined by ELISA.

RESULTS

While MDA and NO levels were higher, levels of SOD, GSH and BDNF were lower in PD patients compared to controls (p < 0.001). The patients with EDS had higher levels of MDA and lower levels of BDNF as compared to those without EDS (p < 0.005). In linear regression analysis, the BDNF levels were dependently associated with SOD levels in PD patients (B: 0.274, p: 0.043). In addition, while a negative correlation existed between BDI scores with BDNF levels (r = -0.312, p = 0.004), a positive correlation was present between BDI scores and MDA levels (r = 0.320, p = 0.005) in PD patients.

CONCLUSION

Our results suggest the presence of high O&NS and low antioxidant capacity accompanied with decreased levels of BDNF in PD patients, especially those with EDS were deeper. These may represent the risk factors for cellular injury and might reveal part of the mechanism causing the depressive state in PD patients.

Insulin resistance and brain-derived neurotrophic factor levels in chronic kidney disease

INTRODUCTION

Insulin resistance is a frequent abnormality in chronic kidney disease (CKD) appearing in early stages. Factors known to promote insulin resistance in CKD patients include disorders of ion and acid-base equilibrium and circulating uremia toxins. Recent research has focused on the central nervous system as the source of the brain-derived neurotrophic factor (BDNF). The aim of our work was to study plasma BDNF concentrations in stage 3 and 4 CKD patients in relationship with insulin resistance and distribution of adipose tissue.

METHOD

Plasma BDNF concentrations were measured in a study group of 31 patients, including a subgroup of 20 non-diabetic subjects. Additionally dual-energy X-ray absorptiometry (DXA) was performed. Homeostatic model assessment of insulin resistance (HOMA-IR) and homeostatic model assessment of B-cell function (HOMA-beta) indices were calculated.

RESULTS

Two separate analyses were performed. In the first analysis performed in all 31 CKD patients, there were no correlations between BDNF and: body mass index (BMI), android, gynoid fat distribution, HOMA-IR and HOMA-beta. In the second analysis performed in 20 CKD patients without diabetes, BDNF was negatively related to gynoid fat (Rs = -0.47, P = 0.034) and women revealed significantly lower levels of BDNF than men (P = 0.046). Normotensive patients disclosed significantly higher BDNF levels than hypertensive patients in the whole CKD group (P = 0.039) and in the non-diabetic subgroup (P = 0.028). No correlations between BDNF and eGFR were found.

CONCLUSIONS

Female sex and arterial hypertension are associated with lower BDNF plasma concentration in CKD patients.

Relationship between levels of brain-derived neurotrophic factor and metabolic parameters in patients with type 2 diabetes mellitus

BACKGROUND AND AIM

Studies have suggested that brain-derived neurotrophic factor (BDNF) plays a role in glucose and lipid metabolism and inflammation. The aim of this study was to evaluate the relationship between serum BDNF levels and various metabolic parameters and inflammatory markers in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

The study included 88 T2DM patients and 33 healthy controls. Fasting blood samples were obtained from the patients and the control group. The serum levels of BDNF were measured with an ELISA kit. The current paper introduces a receiver-operating characteristic (ROC) generalization curve to identify cut-off for the BDNF values in type 2 diabetes patients.

RESULTS

The serum levels of BDNF were significantly higher in T2DM patients than in the healthy controls (206.81 ± 107.32 pg/mL versus 130.84 ± 59.81 pg/mL; P < 0.001). They showed a positive correlation with the homeostasis model assessment of insulin resistance (HOMA-IR) (r = 0.28; P < 0.05), the triglyceride level (r = 0.265; P < 0.05), and white blood cell (WBC) count (r = 0.35; P < 0.001). In logistic regression analysis, age (P < 0.05), body mass index (BMI) (P < 0.05), C-reactive protein (CRP) (P < 0.05), and BDNF (P < 0.01) were independently associated with T2DM. In ROC curve analysis, BDNF cut-off was 137.

CONCLUSION

The serum BDNF level was higher in patients with T2DM. The BDNF had a cut-off value of 137. The findings suggest that BDNF may contribute to glucose and lipid metabolism and inflammation.

Plasma BDNF levels are correlated with aggressiveness in patients with amnestic mild cognitive impairment or Alzheimer disease

In the present study, we examined whether neuropsychiatric symptoms were correlated with plasma brain-derived neurotrophic factor (BDNF) levels as a state marker or were associated with the BDNF polymorphism Val66Met in patients with amnestic mild cognitive impairment (A-MCI) or Alzheimer disease (AD). One hundred and seventy-six outpatients with AD (n = 129) or A-MCI (n = 47) were selected and their plasma BDNF concentrations measured. Next, we investigated the correlation between the plasma BDNF level and the Behavioral Pathology in Alzheimer Disease (Behave-AD) subscale scores, which reflect neuropsychiatric symptoms. We also compared the plasma BDNF level and the Behave-AD subscale scores among the BDNF Val66Met genotypic groups. Among the seven Behave-AD subscale scores, aggressiveness was positively correlated with the plasma BDNF level (ρ = 0.237, P < 0.005), but did not differ significantly among the three BDNF Val66Met genotypic groups. The Behave-AD total and other subscale scores did not differ significantly among the BDNF Val66Met genotypic groups and were not associated with the plasma BDNF level. Moreover, the plasma BDNF level did not differ significantly among the three BDNF Val66Met genotypic groups or between patients with A-MCI and those with AD. The plasma BDNF level was robustly correlated with aggressiveness, implying that the plasma BDNF level might be useful as a behavioral state marker in patients with AD or A-MCI.