Pharmacological and physiological roles of adipokines and myokines in metabolic-related dementia

Plasma proteomic analysis of intermuscular fat links muscle integrity with processing speed in older adults

INTRODUCTION

More intermuscular fat (IMF) has been associated with lower cognitive performance and faster age-associated decline in cognitive function however, the mechanisms driving this relationship have not been fully elucidated. We utilized proteomic analyses to identify the molecular mediators of the association between IMF and cognition to gain further insight into the mechanisms underlying this association.

METHODS

In this cross-sectional study, the plasma proteomic profile of IMF was assessed in the Baltimore Longitudinal Study on Aging (BLSA; n=941, age=66.7±15.2) and validated in the Coronary Artery Risk Development in Young Adults Study (CARDIA; n=2451, age=50.2±3.6). The 7628 plasma proteins were assessed using an aptamer-based assay and tested for association with IMF from the thigh (BLSA) and abdomen (CARDIA). Processing speed assessed by Digit Symbol Substitution Test (DSST). Associations between the main exposures, outcome and mediators were evaluated using linear regression, and mediating effects were assessed by causal mediation analysis adjusting for age, sex, muscle area or muscle volume, self-reported race, and years of education.

RESULTS

Higher IMF was associated with lower DSST performance both in the BLSA and CARDIA studies. There were 722 plasma proteins associated with IMF in both the discovery and replication cohorts (FDR-adjusted p≤0.05). Of the 722 IMF-associated proteins, 26 (24 unique proteins) mediated the relationship between IMF and processing speed with mediation effects ranging from 2.8 to 20.9% (p≤0.05). Overrepresentation analysis of the IMF-associated proteins showed enrichment of proteins in synaptic function and organization, and growth factor binding (FDR-adjusted p≤0.05).

DISCUSSION

There is a robust proteomic signature explaining, at least in part, the link of IMF with DSST. This signature reflected neurological function and growth factor regulation, which are both implicated in lower processing speed. Reducing IMF through behavioral or pharmacological intervention may improve cognition through reduction in growth factor activity and improvements in synaptic activity.

AdipoRon's Impact on Alzheimer's Disease-A Systematic Review and Meta-Analysis

Alzheimer's disease (AD) remains a leading cause of cognitive decline and mortality worldwide, characterized by neurodegeneration, synaptic deficiencies, and neuroinflammation. Despite advancements in early detection, diagnosis, and treatment, AD presents substantial challenges due to its complex pathology, heterogeneity, and the limited efficacy of current therapies. Consequently, there is a pressing need for novel therapeutic agents to target the multifaceted aspects of AD pathology, enhance current treatments, and minimize adverse effects. AdipoRon, an adiponectin receptor agonist, has garnered interest for its potential neuroprotective effects, including reducing neuroinflammation, improving mitochondrial function, and mitigating tau hyperphosphorylation. This review aimed to evaluate the effects of AdipoRon-based adiponectin replacement therapy against AD, using a comprehensive approach grounded in the PICO framework-Population, Intervention, Comparison, and Outcomes. A total of six studies were reviewed, including in vitro and in vivo investigations examining AdipoRon's impact on various AD models. These studies involved different cell lines and transgenic mouse models, assessing various outcomes such as cognitive function, neuroinflammation, tau phosphorylation, synaptic deficiencies, and relevant molecular pathways. By synthesizing data from these studies, our review thoroughly explains AdipoRon's neuroprotective effects, mechanisms of action, and potential as a therapeutic agent for AD. This analysis aims to highlight the current state of knowledge, identify gaps in the research, and suggest directions for future studies and clinical applications.

The role of resistin and adiponectin ratios with uric acid in assessing metabolic syndrome in type 2 diabetes

Metabolic syndrome (MetS) is a growing global healthcare burden. Patients with type 2 diabetes mellitus (T2DM) are more likely to acquire MetS than the general population. Recent research suggests that the interaction of adipose tissue products, such as adiponectin resistin and uric acid, is essential in MetS onset. To examine the role of resistin and adiponectin ratios with uric acid in predicting MetS onset T2DM patients. In a two-year prospective study, 72 T2DM patients were categorised into MetS and non-MetS, according to MetS development. The levels of resistin, adiponectin, uric acid (UA), fasting glucose, high-density lipoprotein cholesterol, and triglycerides were analysed from serum samples. ROC curves and their corresponding areas under the curve (AUC) were utilised to establish the best cut-off values of biomarkers for distinguishing MetS patients and non-MetS patients. The logistic regression analysis was performed to predict the onset of MetS in patients with T2DM. T2DM patients with and without MetS showed significant differences in resistin/UA (p = 0.017), adiponectin/UA (p < 0.001) and adiponectin levels. The Resistin/UA ROC Curve yielded an AUC of 0.825 (p < 0.001), 86.7% sensitivity and 76.2% specificity at a cut-off point of 0.99. Multivariable logistic regression analysis identified resistin /UA ratio [OR 8.631 95% CI 0.450-165.42; p = 0.001] and adiponectin/UA ratio [OR 0.022 95% CI 0.003-0.188; p < 0.001] as independent predictors of MetS. This study confirms the role of resistin-uric acid and adiponectin-uric acid ratios as predictors of MetS development in T2DM patients.

Associations of combined accelerated biological aging and genetic susceptibility with incident dementia: a prospective study in the UK Biobank

BACKGROUND

Accelerated biological aging has been verified to be a critical risk factor for a number of age-related diseases, but its role in dementia remained unclear. Whether it modified the effects of genetic factors was also unknown. This study evaluated the associations between accelerated biological aging and dementia and the moderating role of accelerated biological aging in the genetic susceptibility to the disease.

METHODS

We included 200,731 participants in the UK biobank. Nine clinical blood biomarkers and chronological age were used to calculate Phenotypic age acceleration (PhenoAgeAccel), which is a novel indicator for accelerated biological aging. The associations of PhenoAgeAccel with dementia, both young-onset and late-onset dementia, were assessed by Cox proportional hazard models. Apolipoprotein E (APOE) alleles and polygenic risk scores (PRS) were used to evaluate the genetic risk of dementia. The interactions between genetic susceptibility and biological aging were tested on both multiplicative and additive scales.

RESULTS

These findings showed individuals who were in the highest quartile of PhenoAgeAccel had a higher risk with incidence of dementia compared to individuals in the lowest quartile of PhenoAgeAccel (HR: 1.145 (95% CI: 1.050, 1.249)). Individuals with biologically older had a higher risk of dementia than individuals with biologically younger (HR: 1.069 (95% CI: 1.004, 1.138)). Furthermore, compared to individuals with biologically younger and low APOE ε4-related genetic risk, individuals with biologically younger and high APOE ε4-related genetic risk (HR:3.048 (95% CI: 2.811, 3.305)) had a higher risk of dementia than individuals with biologically older and high APOE ε4-related genetic risk (HR: 2.765 (95% CI: 2.523, 3.029)). Meanwhile, referring to low dementia PRS and biologically younger, the risk of dementia increased by 72.7% (HR: 1.727 (95% CI: 1.538, 1.939) in the biologically younger and high PRS group and 58.7% (HR: 1.587 (95% CI: 1.404, 1.793) in the biologically older and high PRS group, respectively. The negative interactions between PhenoAgeAccel with APOE ε4 and PRS were also tested on the additive scale.

CONCLUSIONS

Accelerated biological aging could bring the extra risk of dementia but attenuate the effects of genetic risk on dementia. These findings provide insights for precise prevention and intervention of dementia.

Glycosaminoglycans' for brain health: Harnessing glycosaminoglycan based biomaterials for treating central nervous system diseases and in-vitro modeling

Dysfunction of the central nervous system (CNS) following traumatic brain injuries (TBI), spinal cord injuries (SCI), or strokes remains challenging to address using existing medications and cell-based therapies. Although therapeutic cell administration, such as stem cells and neuronal progenitor cells (NPCs), have shown promise in regenerative properties, they have failed to provide substantial benefits. However, the development of living cortical tissue engineered grafts, created by encapsulating these cells within an extracellular matrix (ECM) mimetic hydrogel scaffold, presents a promising functional replacement for damaged cortex in cases of stroke, SCI, and TBI. These grafts facilitate neural network repair and regeneration following CNS injuries. Given that natural glycosaminoglycans (GAGs) are a major constituent of the CNS, GAG-based hydrogels hold potential for the next generation of CNS healing therapies and in vitro modeling of CNS diseases. Brain-specific GAGs not only offer structural and biochemical signaling support to encapsulated neural cells but also modulate the inflammatory response in lesioned brain tissue, facilitating host integration and regeneration. This review briefly discusses different roles of GAGs and their related proteoglycan counterparts in healthy and diseases brain and explores current trends and advancements in GAG-based biomaterials for treating CNS injuries and modeling diseases. Additionally, it examines injectable, 3D bioprintable, and conductive GAG-based scaffolds, highlighting their clinical potential for in vitro modeling of patient-specific neural dysfunction and their ability to enhance CNS regeneration and repair following CNS injury in vivo.

Association between Visceral Adipose Tissue Metabolism and Cerebral Glucose Metabolism in Patients with Cognitive Impairment

Visceral adipose tissue (VAT) dysfunction has been recently recognized as a potential contributor to the development of Alzheimer's disease (AD). This study aimed to explore the relationship between VAT metabolism and cerebral glucose metabolism in patients with cognitive impairment. This cross-sectional prospective study included 54 patients who underwent 18F-fluorodeoxyglucose (18F-FDG) brain and torso positron emission tomography/computed tomography (PET/CT), and neuropsychological evaluations. VAT metabolism was measured by 18F-FDG torso PET/CT, and cerebral glucose metabolism was measured using 18F-FDG brain PET/CT. A voxel-based analysis revealed that the high-VAT-metabolism group exhibited a significantly lower cerebral glucose metabolism in AD-signature regions such as the parietal and temporal cortices. In the volume-of-interest analysis, multiple linear regression analyses with adjustment for age, sex, and white matter hyperintensity volume revealed that VAT metabolism was negatively associated with cerebral glucose metabolism in AD-signature regions. In addition, higher VAT metabolism was correlated with poorer outcomes on cognitive assessments, including the Korean Boston Naming Test, Rey Complex Figure Test immediate recall, and the Controlled Oral Word Association Test. In conclusion, our study revealed significant relationships among VAT metabolism, cerebral glucose metabolism, and cognitive function. This suggests that VAT dysfunction actively contributes to the neurodegenerative processes characteristic of AD, making VAT dysfunction targeting a novel AD therapy approach.

Internal mechanism of correlation between angiotensin II gene and serum adiponectin level in patients with cerebrovascular complications of H-type hypertension

Background

The study aimed to explore the correlation between the angiotensin II (Ang II) gene and serum adiponectin expression in patients with cerebrovascular complications of H-type hypertension (HH) and its mechanism.

Methods

A total of 50 cases of outpatient patients in Tianjin Fourth Central Hospital were recruited from January 2022 to June 2023 and rolled into three groups according to their blood pressure and basic information, namely the HH cerebrovascular complications group, the non-H-type hypertension (NHH) group, and the healthy control (HC) group. Peripheral blood samples were taken; one sample was utilized to test for the Ang II gene and the methylation of Ang II, and the other sample was utilized to measure serum adiponectin levels to analyze the relationship between serum adiponectin level and Ang II in patients with cerebrovascular complications of HH.

Results

The ratio of male to female was 8:7 in the group of cerebrovascular complications of HH, and mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 167.34 mm Hg and 112.56 mm Hg, respectively. In the NHH group, the mean SBP was 165.89 mm Hg, and the mean DBP was 113.47 mm Hg. The blood pressure of the HC group was in the normal range. The Ang II content was the highest in the group with cerebrovascular complications of HH, followed by the group with NHH, and the lowest in the HC group.

Conclusions

Pyrosequencing chart of patients with cerebrovascular complications of HH showed that the content of deoxyphosphate ribose G was the highest, while the content of A was the highest in NHH patients. Moreover, the serum adiponectin level of patients with HH and NHH was superior to that of the HC group, and the adiponectin level between the former two groups and the HC group differed considerably. Ang II levels were high in patients with cerebrovascular complications of HH and were positively correlated with adiponectin levels. The incidence of cerebrovascular complications of HH may be related to Ang II levels in patients.

Sarcopenic obesity is part of obesity paradox in dementia development: evidence from a population-based cohort study

BACKGROUND

Sarcopenic obesity, a clinical and functional condition characterized by the coexistence of obesity and sarcopenia, has not been investigated in relation to dementia risk and its onset.

METHODS

We included 208,867 participants from UK biobank, who aged 60 to 69 years at baseline. Dementia diagnoses were identified using hospital records and death register data. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models to evaluate the associations of obesity, sarcopenia, and sarcopenic obesity with dementia risk, stratified by sex. Stratified analyses were performed across dementia-related polygenic risk score (PRS). Restricted mean survival time models were established to estimate the difference and 95%CIs of dementia onset across different status. Additionally, linear regression models were employed to estimate associations of different status with brain imaging parameters. The mediation effects of chronic diseases were also examined.

RESULTS

Obese women with high PRS had a decreased risk (HR = 0.855 [0.761-0.961]), but obese men with low PRS had an increased risk (HR = 1.223 [1.045-1.431]). Additionally, sarcopenia was associated with elevated dementia risk (HRwomen = 1.323 [1.064-1.644]; HRmen = 2.144 [1.753-2.621]) in those with low PRS. Among those with high PRS, however, the association was only significant in early-life (HRwomen = 1.679 [1.355-2.081]; HRmen = 2.069 [1.656-2.585]). Of note, sarcopenic obesity was associated with higher dementia risk (HRwomen = 1.424 [1.227-1.653]; HRmen = 1.989 [1.702-2.323]), and results remained similar stratified by PRS. Considering dementia onset, obesity was associated with dementia by 1.114 years delayed in women, however, 0.170 years advanced in men. Sarcopenia (women: 0.080 years; men: 0.192 years) and sarcopenic obesity (women: 0.109 years; men: 0.511 years) respectively advanced dementia onset. Obesity, sarcopenia, and sarcopenic obesity were respectively related to alterations in different brain regions. Association between sarcopenic obesity and dementia was mediated by chronic diseases.

CONCLUSIONS

Sarcopenic obesity and sarcopenia were respectively associated with increased dementia risk and advanced dementia onset to vary degree. The role of obesity in dementia may differ by sex and genetic background.