The Involvement of Insulin-Like Growth Factor 1 and Nerve Growth Factor in Alzheimer's Disease-Like Pathology and Survival Role of the Mix of Embryonic Proteoglycans: Electrophysiological Fingerprint, Structural Changes and Regulatory Effects on Neurotrophins

Identification of IGF-1 Effects on White Adipose Tissue and Hippocampus in Alzheimer's Disease Mice via Transcriptomic and Cellular Analysis

Alzheimer's disease (AD) stands as the most prevalent neurodegenerative disorder, characterized by a multitude of pathological manifestations, prominently marked by the aggregation of amyloid beta. Recent investigations have revealed a compelling association between excessive adiposity and glial activation, further correlating with cognitive impairments. Additionally, alterations in levels of insulin-like growth factor 1 (IGF-1) have been reported in individuals with metabolic conditions accompanied by memory dysfunction. Hence, our research endeavors to comprehensively explore the impact of IGF-1 on the hippocampus and adipose tissue in the context of Alzheimer's disease. To address this, we have conducted an in-depth analysis utilizing APP/PS2 transgenic mice, recognized as a well-established mouse model for Alzheimer's disease. Upon administering IGF-1 injections to the APP/PS2 mice, we observed notable alterations in their behavioral patterns, prompting us to undertake a comprehensive transcriptomic analysis of both the hippocampal and adipose tissues. Our data unveiled significant modifications in the functional profiles of these tissues. Specifically, in the hippocampus, we identified changes associated with synaptic activity and neuroinflammation. Concurrently, the adipose tissue displayed shifts in processes related to fat browning and cell death signaling. In addition to these findings, our analysis enabled the identification of a collection of long non-coding RNAs and circular RNAs that exhibited significant changes in expression subsequent to the administration of IGF-1 injections. Furthermore, we endeavored to predict the potential roles of these identified RNA molecules within the context of our study. In summary, our study offers valuable transcriptome data for hippocampal and adipose tissues within an Alzheimer's disease model and posits a significant role for IGF-1 within both the hippocampus and adipose tissue.

Analysis of the relationship between mild cognitive impairment and serum klotho protein and insulin-like growth factor-1 in the elderly

BACKGROUND

Mild cognitive impairment (MCI) is a mild memory or cognitive impairment.

OBJECTIVE

To explore the relationship between serum klotho (K1) protein and insulin-like growth factor-1 and mild cognitive impairment in the elderly in order to provide accurate and appropriate indicators for clinical diagnosis and treatment of MCI.

METHODS

This randomized stratified study adopted a multistage cluster sampling method. 161 elderly patients with mild cognitive impairment were included as the MCI group, and 161 healthy people matched with the MCI group in gender, age and education were selected as the control group.

RESULTS

The levels of serum K1 protein and insulin-like growth factor-1 in the MCI group were lower than those in the control group (P< 0.05). Both IGF-1 and K1 had predictive value for MCI (P< 0.05). The area under the curve (AUC) of IGF-1 for predicting MCI was 0.859 (95% CI: 0.790∼0.929), and the AUC of K1 for predicting MCI was 0.793 (95% CI: 0.694∼0.892). The value of joint prediction of the two indicators was the highest, with an AUC of 0.939 (95% CI: 0.896-0.993).

CONCLUSION

High serum K1 and insulin-like growth factor-1 are the protective factors of cognitive impairment in MCI patients. Both IGF-1 and serum K1 proteins have predictive value for MCI, and the combination of the two indicators has the highest predictive value.

Effects of β-amyloid (1-42) Administration on the Main Neurogenic Niches of the Adult Brain: Amyloid-Induced Neurodegeneration Influences Neurogenesis

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder and warrants further study as well as timely treatment. Additionally, the mechanisms of the brain's intrinsic defense against chronic injury are not yet fully understood. Herein, we examined the response of the main neurogenic niches to amyloid exposure and the associated changes in structure and synaptic activity. Flow cytometry of Nestin-, Vimentin-, Nestin/Vimentin-, NeuN-, GFAP-, NeuN/GFAP-, NSE-, BrdU-, Wnt-, BrdU/Wnt-, VEGF-, Sox14-, VEGF/Sox14-, Sox10-, Sox2-, Sox10/Sox2-, Bax-, and Bcl-xL-positive cells was performed in the subventricular zone (SVZ), hippocampus, and cerebral cortex of rat brains on 90th day after intracerebroventricular (i.c.v.) single injection of a fraction of β-amyloid (Aβ) (1-42). The relative structural changes in these areas and disruptions to synaptic activity in the entorhinal cortex-hippocampus circuit were also evaluated. Our flow analyses revealed a reduction in the numbers of Nestin-, Vimentin-, and Nestin/Vimentin-positive cells in neurogenic niches and the olfactory bulb. These changes were accompanied by an increased number of BrdU-positive cells in the hippocampus and SVZ. The latter changes were strongly correlated with changes in the numbers of VEGF- and VEGF/Sox14-positive cells. The morphological changes were characterized by significant neural loss, a characteristic shift in entorhinal cortex-hippocampus circuit activity, and decreased spontaneous alternation in a behavioral test. We conclude that although an injection of Aβ (1-42) induced stem cell proliferation and triggered neurogenesis at a certain stage, this process was incomplete and led to neural stem cell immaturity. We propose the idea of enhancing adult neurogenesis as a promising strategy for preventing dementia at healthy elderly people andpeople at high risk for developing AD, or treating patients diagnosed with AD.

The combination of autologous mesenchymal stem cell-derived exosomes and neurotrophic factors as an intervention for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a chronic progressive degeneration of motor neurons and has a high mortality. Riluzole and edaravone are the only approved medications currently being used for amyotrophic lateral sclerosis in clinical settings. However, they can lead to serious complications, such as injuries to the liver and kidney. To date, there is no effective treatment for amyotrophic lateral sclerosis. In this regard, investigations concerning the employment of exosomes, mesenchymal stem cells, and neurotrophic factors to ameliorate amyotrophic lateral sclerosis are attracting considerable attention in the scientific community. Herein, we systematically analyze the relationship relevant to autologous mesenchymal stem cell derived-exosomes, neurotrophic factors and amyotrophic lateral sclerosis. Mesenchymal stem cells modulate immune response, mitigate oxidative stress, promote neuronal regeneration, and differentiate into neuronal and glial cells. Furthermore, exosomes from mesenchymal stem cells exert beneficial effects on their mother cells by preventing abnormal differentiation of mesenchymal stem cells. Similarly, neurotrophic factors regulate inflammatory response, stimulate the neuron repair, and the recovery of neuronal functioning. Therefore, autologous mesenchymal stem cells-derived exosomes combined with neurotrophic factors could potentially be an effective interventional medium for amyotrophic lateral sclerosis.

The impact of physical activity on blood inflammatory cytokines and neuroprotective factors in individuals with mild cognitive impairment: a systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

Accumulated evidence has proved that both neuroinflammation and neuroprotection existing at the stage of mild cognitive impairment (MCI) may mediate its progression, which can conversely be modulated by physical activity (PA). However, further research is needed to clarify which factors are involved in that process.

OBJECTIVES

To identify the impact of PA on inflammatory cytokines and neuroprotective factors in individuals with MCI.

METHODS

Four databases [PubMed, Cochrane Library, Cochrane Library (Trials), Embase and Web of Science Core Collection] were searched from their inception to October 2021 for randomized-controlled trials (RCTs) assessing the biochemical effect of PA on biomarkers in participants with MCI. Pooled effect size was calculated by the standardized mean difference (SMD).

RESULTS

A total of 13 RCTs involving 514 participants by reporting 8 inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, -6, -8, -10, -15, C-reactive protein (CRP) and interferon-γ (IFN-γ) and 5 neuroprotective factors (brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), irisin] were included. The meta-analysis showed that PA had positive effects on decreasing TNF-α (SMD =  - 0.32, 95% CI - 0.58 to 0.07, p = 0.01; I² = 32%) and CRP (SMD = - 0.68, 95% CI - 1.05 to 0.32, p = 0.0002; I² = 18%), while significantly improving BDNF (SMD = 0.32, 95% CI 0.09-0.56, p = 0.007; I² = 42%) and IGF-1 (SMD = 0.42, 95% CI 0.03-0.81, p = 0.03; I² = 0%).

CONCLUSION

PA had a certain effect on inhibiting inflammatory cytokines but promoting neuroprotective factors in individuals with MCI which may provide a possible explanation for the potential molecular mechanism of PA on cognitive improvement.