Altered plasma visfatin levels and insulin resistance in patients with Alzheimer's disease

Changes in Taste Perception in Patients with Minor and Major Cognitive Impairment Linked to Alzheimer's Disease Recorded by Gustatory Evoked Potentials

BACKGROUND

The need for early diagnosis biomarkers in Alzheimer's disease (AD) is growing. Only few studies have reported gustatory dysfunctions in AD using subjective taste tests.

OBJECTIVE

The main purpose of the study was to explore gustatory functions using subjective taste tests and recordings of gustatory evoked potentials (GEPs) for sucrose solution in patients with minor or major cognitive impairment (CI) linked to AD, and to compare them with healthy controls. The secondary objective was to evaluate the relationships between GEPs and the results of cognitive assessments and fasting blood samples.

METHODS

A total of 45 subjects (15 healthy subjects, 15 minor CI patients, 15 major CI patients) were included to compare their gustatory functions and brain activity by recording GEPs in response to a sucrose stimulation. CI groups were combined in second analyses in order to keep a high power in the study. Correlations were made with cognitive scores and hormone levels (ghrelin, leptin, insulin, serotonin).

RESULTS

Increased P1 latencies and reduced N1 amplitudes were observed in minor or major patients compared to controls. GEPs were undetectable in 6 major and 4 minor CI patients. Thresholds for sucrose detection were significantly higher in the major CI group than in controls or the minor CI group. No correlation was found with hormone levels.

CONCLUSIONS

The cortical processing of sensory taste information seems to be altered in patients with minor or major CI linked to AD. This disturbance was identifiable with subjective taste tests only later, at the major CI stage.

Efficacy of Glucose Metabolism-Related Indexes on the Risk and Severity of Alzheimer’s Disease: A Meta-Analysis

Background: Considering the strong correlation made between Alzheimer’s disease (AD) and the pathology of glucose metabolism disorder, we sought to analyze the effects of fasting blood glucose (FBG) level, fasting plasma insulin (FINS) level, and insulin resistance index (HOMA-IR) on the risk and severity of AD. Objective: Reveal the pathological relationship between AD and insulin resistance. Methods: We searched 5 databases from inception through April 4, 2022. Meta-regression was conducted to identify if there were significant differences between groups. Shapiro-Wilk test and the Q-Q diagram were applied to evaluate the normality of variables. A multiple logistic regression model was employed to explore the association between FBG, FINS, HOMA-IR, and Mini-Mental State Examination scale score (MMSE). Results: 47 qualified articles including 2,981 patients were enrolled in our study. FBG (p < 0.001), FINS (p < 0.001), and HOMA-IR (p < 0.001) were higher in AD patients than in controls. HOMA-IR was negatively correlated with MMSE (p = 0.001) and positively related to the sex ratio (male versus female) (p < 0.05). HOMA-IR obeyed lognormal distribution (p > 0.05), and the 95% bilateral boundary values were 0.73 and 10.67. FBG (p = 0.479) was positively correlated to MMSE, while FINS (p = 0.1657) was negatively correlated with MMSE. Conclusion: The increase in the levels of FBG, FINS, and HOMA-IR served as precise indicators of the risk of AD. HOMA-IR was found to be correlated to the increasing severity of AD, especially in male AD patients.

Preoperative plasma visfatin may have a dual effect on the occurrence of postoperative delirium

BACKGROUND

Visfatin is considered to be a "novel pro-inflammatory cytokine." Neuroinflammatory response is one of the important mechanisms of postoperative delirium (POD). The relationship between preoperative plasma visfatin and POD is unclear.

OBJECTIVE

To investigate the relationship between preoperative plasma visfatin concentrations and POD (primary outcome) in older hip fracture patients and to explore whether it affects POD through inflammatory factors.

MATERIALS AND METHODS

This prospective cohort study enrolled 176 elderly patients who were scheduled for hip fracture surgery. Preoperative plasma was collected on the morning of surgery, and visfatin levels were measured. Interleukin (IL)-1 and IL-6 were measured using patients' plasma collected on the first day after surgery. We used the 3-min diagnostic interview for Confusion Assessment Method-defined delirium (3D-CAM) twice daily within the 2 days after surgery to assess whether POD had occurred. Restricted cubic splines and piecewise regression were used to explore the relationship between preoperative plasma visfatin concentrations and POD, and further mediation analysis was used to verify whether visfatin plays a role in POD through regulating inflammatory factors.

RESULTS

The incidence of POD was 18.2%. A J-shaped association was observed between preoperative plasma visfatin levels and POD. The risk of POD decreased within the lower visfatin concentration range up to 37.87 ng/ml, with a hazard ratio of 0.59 per 5 ng/ml [odds ratio (OR) = 0.59, 95% confidence interval (CI) = 0.37-0.95], but the risk increased above this concentration (P for non-linearity < 0.001, with a hazard ratio of 1.116 per 10 ng/ml; OR = 1.10, 95% CI = 1.02-1.23). Mediation effect analysis showed that when the plasma visfatin concentration was higher than 37.87 ng/ml, the effect of visfatin on POD was mediated by IL-6 (p < 0.01). A significant indirect association with postoperative plasma IL-6 was observed between preoperative plasma visfatin and POD (adjusted β = 0.1%; 95% CI = 4.8∼38.9%; p < 0.01).

CONCLUSION

Visfatin is the protective factor in POD when the preoperative plasma visfatin concentration is below 37.87 ng/ml, but when it exceeds 37.87 ng/ml, the visfatin concentration is a risk factor for POD, which is mediated by postoperative plasma IL-6. The results suggest that preoperative visfatin may have a dual effect on the POD occurrence.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [ChiCTR21 00052674].

Role of visfatin in obesity-induced insulin resistance

The growing worldwide burden of insulin resistance (IR) emphasizes the importance of early identification for improved management. Obesity, particularly visceral obesity, has been a key contributing factor in the development of IR. The obesity-associated chronic inflammatory state contributes to the development of obesity-related comorbidities, including IR. Adipocytokines, which are released by adipose tissue, have been investigated as possible indicators of IR. Visfatin was one of the adipocytokines that attracted attention due to its insulin-mimetic activity. It is released from a variety of sources, including visceral fat and macrophages, and it influences glucose metabolism and increases inflammation. The relationship between visfatin and IR in obesity is debatable. As a result, the purpose of this review was to better understand the role of visfatin in glucose homeostasis and to review the literature on the association between visfatin levels and IR, cardiovascular diseases, and renal diseases in obesity.

Alzheimer's disease: a step closer to understanding type 3 diabetes in African Americans

Alzheimer's disease (AD) is the fourth leading cause of death in the United States and the most common cause of adult-onset dementia. Recent results suggest an increased prevalence and severity in African Americans compared to Caucasians. Our understanding of the potential mechanism(s) underlying this ethnicity difference is limited. We previously described ethnicity-related differences in levels of neurodegenerative proteins and cytokines/chemokines in the BA21 region of African Americans and Caucasians with AD. Here, similar multiplex assays were used to examine those endpoints in patient postmortem cerebrospinal fluid (CSF). Additionally, we measured levels of C-peptide, ghrelin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon, insulin, leptin, PAI-1, resistin, and visfatin using a human diabetes 10-plex assay. The cytokine and chemokine assays revealed that levels of 26 chemokines or cytokines differed significantly with ethnicity, and three of those were significantly associated with gender. The neurodegenerative disease panel indicated that levels of soluble RAGE were significantly elevated in African Americans compared to Caucasians. All measures in the diabetes disease panel assay were significantly elevated in African Americans: ghrelin, GIP, GLP-1, glucagon, insulin, and visfatin. Through peripheral sample analysis, these results provide further evidence that ethnicity is critically involved in the manifestation of AD.

Handgrip strength, tumor necrosis factor-α, interlukin-6, and visfatin levels in oldest elderly patients with cognitive impairment

INTRODUCTION

Handgrip strength is associated with mild cognitive impairment. Tumor necrosis factor [TNF]-α and interleukin [IL]-6 were pro-inflammatory cytokines influencing the severity of initial neurological deficit. Visfatin is a novel adipokine and has a strong correlation with inflammation. The relationships of TNF-α, IL-6 and visfatin are not consistent, and no study has investigated them in the elderly patients with cognitive impairment.

METHODS

This study included patients aged ≥75 years at the emergency department from August 2018 to February 2019. All patients underwent comprehensive geriatric assessment and blood tests for fasting plasma TNF-α, IL-6 and visfatin levels.

RESULTS

We enrolled 106 elderly patients with a mean age of 87.3 years, including 62 (58.4%) patients in cognitive impairment group (Mini-Mental State Examination [MMSE] < 24) and 44 (41.5%) patients in the non-cognitive impairment group. Compared to the non-cognitive impairment group, the cognitive impairment group had significantly lower handgrip strength, and significantly higher TNF-α, IL-6 and visfatin levels. TNF-α positively correlated with IL-6. Both TNF-α and IL-6 negatively correlated with Barthel index and MMSE. Handgrip strength negatively correlated with TNF-α but positively correlated with Barthel index and MMSE scores. Backward and stepwise multiple logistic regression analyses showed that the independent predictor for cognitive impairment was handgrip strength and age.

CONCLUSION

The cognitive impairment group had significantly higher serum TNF-α, IL-6, and visfatin levels. The independent predictors of cognitive impairment were handgrip strength and age. Handgrip strength negatively correlated with TNF-α and IL-6 but positively with Barthel index and MMSE scores.

Extracorporeal apheresis therapy for Alzheimer disease-targeting lipids, stress, and inflammation

Current therapeutic approaches to Alzheimer disease (AD) remain disappointing and, hence, there is an urgent need for effective treatments. Here, we provide a perspective review on the emerging role of "metabolic inflammation" and stress as a key factor in the pathogenesis of AD and propose a novel rationale for correction of metabolic inflammation, increase resilience and potentially slow-down or halt the progression of the neurodegenerative process. Based on recent evidence and observations of an early pilot trial, we posit a potential use of extracorporeal apheresis in the prevention and treatment of AD. Apolipoprotein E, lipoprotein(a), oxidized LDL (low density lipoprotein)'s and large LDL particles, as well as other proinflammatory lipids and stress hormones such as cortisol, have been recognized as key factors in amyloid plaque formation and aggravation of AD. Extracorporeal lipoprotein apheresis systems employ well-established, powerful methods to provide an acute, reliable 60-80% reduction in the circulating concentration of these lipid classes and reduce acute cortisol levels. Following a double-membrane extracorporeal apheresis in patients with AD, there was a significant reduction of proinflammatory lipids, circulating cytokines, immune complexes, proinflammatory metals and toxic chaperones in patients with AD. On the basis of the above, we suggest designing clinical trials to assess the promising potential of such "cerebropheresis" treatment in patients with AD and, possibly, other neurodegenerative diseases.