The Correlations among Depressive Symptoms, Cognitive Performance and Serum BDNF Levels in the Patients with Chronic Kidney Disease

The Plasma Neurofilament Light Chain, Brain-Derived Neurotrophic Factor, and Risk of Depression in Chronic Hemodialysis Patients

INTRODUCTION

Depression is highly prevalent among hemodialysis patients. Understanding the relationship between the plasma neurofilament light chain (NfL) and brain-derived neurotrophic factor (BDNF) may help us to better understand the mechanisms of depression. This study determined their impact, alongside that of other factors, on the risk of depression in hemodialysis patients.

METHODS

The study enrolled 82 patients undergoing chronic hemodialysis. Serum NfL, BDNF, uric acid, urea, potassium, calcium, phosphorus, intact parathyroid hormone, and C-reactive protein (CRP) levels were measured. The patients completed the Beck Depression Inventory (BDI). Blood pressure values, body mass before and after hemodialysis, and weekly duration of hemodialysis in hours were assessed. For 19-month survival analysis, the patients were stratified according to baseline BDI scores.

RESULTS

Based on the BDI score, 18.3% of the patients had an increased risk of depression. Lower scores were associated with significantly longer duration of hemodialysis treatment (37.5 (25-57) 24 (14-37) months, p = 0.01). Within the 19-month survival analysis, 31.7% of patients died. The patients with BDI scores above the median had significantly lower survival than those below the median (log-rank test p = 0.02). No significant differences in serum BDNF levels (192.7 [125.2-278.2]; 207.7 [142.8-265.8] pg/mL, p = 0.40), or NfL concentrations (1431.5 [1182.6-1625.7]; 1494.6 [1335.7-1667] kDa, p = 0.52) were found between patients with lower and higher risk of depression. Patients with BDI scores above the median had significantly higher levels of CRP (9.6 [4.4-14]) than those with scores below the median (3.6 [2.2-7.5], p = 0.01). A significant positive correlation was found between the BDI score and serum CRP level (r = 0.38, p = 0.01). A significant negative correlation was observed between the BDI score and URR% value (r = -0.36, p = 0.02).

CONCLUSIONS

Patients with lower BDI scores had a longer dialysis duration, indicating a potential negative association between depression risk and length of dialysis treatment. Neither serum NfL nor BDNF levels can serve as markers of depression risk in the dialysis population.

Comparison of two self-report scales to assess anxiety and depressive symptoms in hemodialysis patients

INTRODUCTION

Psychiatric illness is prevalent among hemodialysis (HD) patients. This study compared the assessment of anxiety and depressive symptoms among HD patients using two self-administered scales; hospital anxiety and depression scale (HADS) and brief symptom inventory (BSI).

METHODS

A cross-sectional study was conducted among a convenience sample of HD patients (n = 352) from different dialysis centers in Jordan. Patients were interviewed in dialysis units, and demographics, clinical status, disease, and dialysis history data were collected. Symptoms of anxiety (HADS-A ≥ 8 and BSI-A ≥ 0.82) and depression (HADS-D ≥ 8 and BSI-D ≥ 0.82) were also measured.

RESULTS

The mean age of participants was 52.2 ± 15.6 years. The majority had been receiving HD three times daily and for >2 years. A significant moderate-strong correlation was observed between HADS-A and BSI-A (r = 0.753, p < 0.0001) as well as HADS-D and BSI-D (r = 0.588, p < 0.0001). Anxiety prevalence was 43.7 % using HADS-A ≥ 8 and 80.7 % using BSI-A ≥ 0.82, while depression prevalence was 53.1 % using HADS-D ≥ 8 and 51.7 % using BSI-D ≥ 0.82. When HADS was used as a standard, the operating characteristics reveal that a higher cut-off for BSI-A is recommended (≥1.58) for better anxiety screening.

DISCUSSION

Specific and suitable cut-off points need to be further explored and validated for HADS and BSI scales among patients undergoing dialysis.

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.

LncRNA ANRIL mediates endothelial dysfunction through BDNF downregulation in chronic kidney disease

Endothelial dysfunction is common in patients with chronic kidney disease (CKD), but the mechanism is unknown. In this study, we found that the circulating ANRIL level was increased and correlated with vascular endothelial dysfunction in patients with CKD, also negatively correlated with plasma brain-derived neurotrophic factor (BDNF) concentration. We constructed the ANRIL knockout mice model, and found that ANRIL deficiency reversed the abnormal expression of BDNF, along with endothelial nitric oxide synthase (eNOS), vascular adhesion molecule 1 (VCAM-1) and Von Willebrand factor (vWF). Meanwhile, mitochondrial dynamics-related proteins, Dynamin-related protein 1 (Drp1) and mitofusins (Mfn2) level were also recovered. In addition, in vitro, serum derived from CKD patients and uremia toxins induced abnormal expression of ANRIL. By making use of the gain- and loss-of-function approaches, we observed that ANRIL mediated endothelial dysfunction through BDNF downregulation. To explore the specific mechanism, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) were used to explore the binding of ANRIL to histone methyltransferase Enhancer of zeste homolog 2 (EZH2). Further experiments found increased EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) levels at the BDNF promoter region. Collectively, we demonstrated that ANRIL mediate BDNF transcriptional suppression through recruitment of EZH2 to the BDNF promoter region, then regulated the proteins expression related to endothelial function and mitochondrial dynamics. This study provides new insights for the study of endothelial dysfunction in CKD.

Moderate-intensity continuous training and high-intensity interval training improve cognition, and BDNF levels of middle-aged overweight men

The prevalence of overweight and obesity is increasing worldwide, which has been associated with poor cognitive outcomes. Participating in regular physical exercise may also improve cognition, and levels of brain-derived neurotrophic factor (BDNF), but the optimal exercise prescription remains to be elucidated. The purpose of the present study is to compare the effects of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on cognition, and serum BDNF levels in middle-aged and overweight men. Twenty-five sedentary, overweight men participated in the 8-week training intervention. Subjects were randomized into MICT (n = 12) or HIIT (n = 13) and performed exercise sessions 3x/week for 8-weeks. Cognitive function, and serum BDNF levels were assessed pre- and post-intervention. Statistical analysis was carried out using the Graph Pad Prism 7.0, and the level of significance was set at 5%. Significant improvements were observed in cognitive test scores, and BDNF levels in MICT and HIIT groups (p < 0.05). There were no significant differences in cognitive function between MICT and HIIT. The present study implicates that 8 weeks of MICT or HIIT may be a very useful non-pharmacological treatment option to improve cognitive function, and BDNF levels in middle-aged overweight men.

Comparison of pre- and post-hemodialysis PHQ-9 depression scores in patients with end-stage renal disease: A cross-sectional study

OBJECTIVES

An overlap between the somatic symptoms of depression and those of uremia seen in end-stage renal disease (ESRD) patients may affect the diagnosis of depression. This study aims to evaluate the effect of hemodialysis on the diagnosis of depression among patients on maintenance hemodialysis as dialysis diminishes the uremic symptoms, and to compare depression scores before and after dialysis.

METHODS

This was a cross-sectional analytic study conducted from November 2018 through April 2019, in three tertiary hospitals. Consenting participants aged 18 years or older, who had received hemodialysis for at least three months were included. The Patient Health Questionnaire (PHQ-9) tool was used to collect patients' data and to identify symptoms of depression Pre- and post-hemodialysis. Depression scores were compared using the paired sample Wilcoxon rank test or the McNemar test, where appropriate.

RESULTS

Overall, 163 participants were enrolled in the study. The average age of the participants was 56.5 years old, whereas 44.8% were females. The prevalence of depressive symptoms before hemodialysis was 48.5%, with prevalence of mild, moderate and moderately severe of 34.4%, 11.7% and 2.5%, respectively. On the other hand, the prevalence of depressive symptoms after hemodialysis was 46.6% with 36.8%, 9.2% and 0.6% of the participants reporting mild, moderate and moderately severe symptoms, respectively. We found no significant difference in depression scores before and after dialysis (p-values > 0.05).

CONCLUSION

Our study supports the fact that the prevalence of depression is high among patients with ESRD on maintenance hemodialysis. We didn't find a significant difference in depression scores among hemodialysis patients before and after dialysis, with negligible effect of uremic symptoms on the diagnosis of depression. We suggest adopting routine screening of depression among this high-risk group of patients.

Effects of a Psychobiotic Supplement on Serum Brain-derived Neurotrophic Factor Levels in Depressive Patients: A Post Hoc Analysis of a Randomized Clinical Trial

Background/Aims

Psychobiotics are probiotics or prebiotics that, upon ingestion in adequate amounts, yield positive influence on mental health via microbiota-gut-brain axis regulation to modulate the circulating cytokines, chemokines, neurotransmitters, or neurotrophins levels. We have recently shown that a psychobiotic combination (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175; CEREBIOME) significantly improved depression symptoms in patients with depression. Recent animal data suggest the influence of the gut microbiota on brain-derived neurotrophic factor (BDNF), which was shown to correlate with antidepressant response in depressive patients. Therefore, we conducted this exploratory post hoc analysis of BDNF levels to clarify the mechanism of action of this psychobiotic in our cohort.

Methods

Our study was a double-blind, randomized controlled trial of patients with low-to-moderate depression receiving either a probiotic combination, prebiotic or placebo. From the 110 patients randomized in the trial, 78 were included in this post hoc analysis (probiotic, n = 28; prebiotic and placebo, n = 25). We compared serum BDNF levels from participants at baseline and endpoint, and assessed the Pearson correlation between depression severity and BDNF levels for each intervention.

Results

We found that post-intervention BDNF levels were significantly different between groups (P < 0.001). Furthermore, BDNF levels increased significantly in the probiotic group compared to both the prebiotic (P < 0.001) and placebo groups (P = 0.021), which inversely correlated with depression severity compared to placebo (ANOVA/ANCOVA, P = 0.012; Pearson, r = -0.79, P < 0.001). In the prebiotic group, BDNF levels reduced but not significantly compared with placebo group (P > 0.05).

Conclusion

Eight-week supplementation with B. longum and L. helveticus in depressive patients improved depression symptoms, possibly by increasing BDNF levels.