From Metabolic Syndrome to Neurological Diseases: Role of Autophagy

New insights into the interplay between autophagy, gut microbiota and insulin resistance in metabolic syndrome

Metabolic syndrome (MetS) is a widespread and multifactorial disorder, and the study of its pathogenesis and treatment remains challenging. Autophagy, an intracellular degradation system that maintains cellular renewal and homeostasis, is essential for maintaining antimicrobial defense, preserving epithelial barrier integrity, promoting mucosal immune response, maintaining intestinal homeostasis, and regulating gut microbiota and microbial metabolites. Dysfunctional autophagy is implicated in the pathological mechanisms of MetS, involving insulin resistance (IR), chronic inflammation, oxidative stress, and endoplasmic reticulum (ER) stress, with IR being a predominant feature. The study of autophagy represents a valuable field of research with significant clinical implications for identifying autophagy-related signals, pathways, mechanisms, and treatment options for MetS. Given the multifactorial etiology and various potential risk factors, it is imperative to explore the interplay between autophagy and gut microbiota in MetS more thoroughly. This will facilitate the elucidation of new mechanisms underlying the crosstalk among autophagy, gut microbiota, and MetS, thereby providing new insights into the diagnosis and treatment of MetS.

IL-10 and IL-1β Serum Levels, Genetic Variants, and Metabolic Syndrome: Insights into Older Adults' Clinical Characteristics

Populational aging is marked by chronic noncommunicable diseases, such as metabolic syndrome (MetS). IL-10 and IL-1β are pleiotropic cytokines with multiple biological effects linked to metabolic disorders. This cross-sectional study assessed 193 participants' IL-10 and IL-1β serum levels regarding their role in developing MetS, clinical characteristics, and their IL1B rs1143627 and IL10 rs1800890 variants' genotype frequencies in a population over 60. IL-10 levels correlated weakly with HDL levels and fat mass and inversely with triglycerides, glucose, glycated hemoglobin, and estimated average blood glucose levels. IL-10 levels were also indirectly influenced by the patient's T2DM duration, lean mass amount, and bone mineral content. Participants with altered HDL, elevated serum glucose, raised HbA1c levels, or those over 80 had reduced serum IL-10 levels compared to those with normal levels or other age groups, respectively. Women also had higher serum IL-10 levels than men. Dissimilarly, IL-1β levels correlated directly only with the number of total leukocytes and segmented neutrophils, showing only significant variations with self-reported alcohol consumption. Our study also found that those with the IL10 AA genotype (lower IL-10 levels) had a significantly higher risk of developing MetS. These findings may help direct future research and more targeted therapeutic approaches in older adults.

Different types of cell death in diabetic endothelial dysfunction

Diabetes mellitus is a metabolic disease caused by disorders of insulin secretion and utilization. Long-term hyperglycemia, insulin resistance, and disorders of glucose and lipid metabolism cause vascular endothelial cell damage. Endothelial dysfunction is a key feature of diabetic vascular complications such as diabetic nephropathy, retinopathy, neuropathy, and atherosclerosis. Importantly, cell death is thought to be a key factor contributing to vascular endothelial injury. Morphologically, cell death can be divided into three forms: type I apoptosis, type II autophagy, and type III necrosis. According to the difference in function, cell death can be divided into accidental cell death (ACD) and regulated cell death (RCD). RCD is a controlled process involving numerous proteins and precise signaling cascades. Multiple subroutines covered by RCD may be involved in diabetic endothelial dysfunction, including apoptosis, autophagy, necroptosis, pyroptosis, entosis, ferroptosis, ferroautophagy, parthanatos, netotic cell death, lysosome-dependent cell death, alkaliptosis, oxeiptosis, cuproptosis, and PANoptosis. This article briefly reviews the mechanism and significance of cell death associated with diabetic endothelial dysfunction, which will help deepen the understanding of diabetic endothelial cell death and provide new therapeutic ideas.

Multi-Tiered Assessment of Gene Expression Provides Evidence for Mechanisms That Underlie Risk for Type 2 Diabetes

Introduction

Integrated transcriptome and microRNA differential gene expression (DEG) analyses may help to explain type 2 diabetes (T2D) pathogenesis in at-risk populations. The purpose of this study was to characterize DEG in banked biospecimens from underactive adult participants who responded to a randomized clinical trial measuring the effects of lifestyle interventions on T2D risk factors. DEGs were further examined within the context of annotated biological pathways.

Methods

Participants (n = 52) in a previously completed clinical trial that assessed a 12-week behavioural intervention for T2D risk reduction were included. Participants who showed >6mg/dL decrease in fasting blood glucose were identified as responders. Gene expression was measured by RNASeq, and overrepresentation analysis within KEGG pathways and weighted gene correlation network analysis (WGCNA) were performed.

Results

No genes remained significantly differentially expressed after correction for multiple comparisons. One module derived by WGCNA related to body mass index was identified, which contained genes located in KEGG pathways related to known mechanisms underlying risk for T2D as well as pathways related to neurodegeneration and protein misfolding. A network analysis showed indirect connections between genes in this module and islet amyloid polypeptide (IAPP), which has previously been hypothesized as a mechanism for T2D.

Discussion

We validated prior studies that showed pathways related to metabolism, inflammation/immunity, and endocrine/hormone function are related to risk for T2D. We identified evidence for new potential mechanisms that include protein misfolding. Additional studies are needed to determine whether these are potential therapeutic targets to decrease risk for T2D.

Changes in Plasma Neutral and Ether-Linked Lipids Are Associated with The Pathology and Progression of Alzheimer's Disease

Aberrant lipid metabolism has been strongly linked to Alzheimer's disease (AD) pathogenesis. However, the role of lipids in the pathophysiological processes of AD and their clinical progression is unclear. We hypothesized that plasma lipids are associated with the pathological hallmarks of AD, progression from mild cognitive impairment (MCI) to AD, and the rate of cognitive decline in MCI patients. To evaluate our hypotheses, we analysed the plasma lipidome profile by liquid chromatography coupled to mass spectrometry in an LC-ESI-QTOF-MS/MS platform for 213 subjects recruited consecutively: 104 AD, 89 MCI, and 20 control subjects. Forty-seven (52.8%) MCI patients progressed to AD during follow-up (58 ± 12.5 months). We found that higher plasma levels of sphingomyelin SM(36:0) and diglyceride DG(44:3) were associated with an increased risk of amyloid beta 42 (Aβ42) positivity in CSF, while levels of SM(40:1) were associated with a reduced risk. Higher plasma levels of ether-linked triglyceride TG(O-60:10) were negatively associated with pathological levels of phosphorylated tau in CSF. Plasma levels of fatty acid ester of hydroxy fatty acid FAHFA(34:0) and ether-linked phosphatidylcholine PC(O-36:1) were positively associated with pathological levels of total tau in CSF. Regarding the plasma lipids most associated with progression from MCI to AD, our analysis detected phosphatidyl-ethanolamine plasmalogen PE(P-36:4), TG(59:12), TG(46:0), and TG(O-62:7). Furthermore, TG(O-62:7) was the lipid that was most strongly associated with the rate of progression. In conclusion, our results indicate that neutral and ether-linked lipids are involved in the pathophysiological processes of AD and the progression from MCI to AD dementia, suggesting the involvement of lipid-mediated antioxidant mechanisms in AD.

Palmitic Acid Modulates Microglial Cell Response to Metabolic Endotoxemia in an In Vitro Study

Metabolic endotoxemia (ME) is characterized by a 2-3-fold increase in blood endotoxin levels and low-grade systemic inflammation without apparent infection. ME is usually accompanied by metabolic syndrome, characterized by central obesity and hyperlipidemia. According to numerous studies, ME may lead to functional brain disorders, including cognitive decline, depression, and dementia. In the current in vitro study, we aimed to determine the direct and indirect impact of endotoxin (LPS) and palmitic acid (PA), representing saturated fatty acids, on the inflammatory and oxidative stress response in the human microglial HMC3 cells unstimulated and stimulated with IFNγ. The study's results revealed that direct HMC3 cell exposition to endotoxin and PA increased inflammatory response measured as levels of IL-6 and MCP-1 released into the medium and PGE2 levels in cell lysates. Moreover, direct HMC3 cell treatment with PA and LPS induced oxidative stress, i.e., ROS and COX-2 production and lipid peroxidation. On the contrary, an indirect effect of LPS and PA on microglial cells, assessed as the impact of macrophage metabolites, was much lower regarding the inflammatory response, although still associated with oxidative stress. Interestingly, IFNγ had a protective effect on microglial cells, reducing the production of pro-inflammatory mediators and oxidative stress in HMC3 cells treated directly and indirectly with LPS and PA.

Neuro-Vulnerability in Energy Metabolism Regulation: A Comprehensive Narrative Review

This comprehensive narrative review explores the concept of neuro-vulnerability in energy metabolism regulation and its implications for metabolic disorders. The review highlights the complex interactions among the neural, hormonal, and metabolic pathways involved in the regulation of energy metabolism. The key topics discussed include the role of organs, hormones, and neural circuits in maintaining metabolic balance. The review investigates the association between neuro-vulnerability and metabolic disorders, such as obesity, insulin resistance, and eating disorders, considering genetic, epigenetic, and environmental factors that influence neuro-vulnerability and subsequent metabolic dysregulation. Neuroendocrine interactions and the neural regulation of food intake and energy expenditure are examined, with a focus on the impact of neuro-vulnerability on appetite dysregulation and altered energy expenditure. The role of neuroinflammation in metabolic health and neuro-vulnerability is discussed, emphasizing the bidirectional relationship between metabolic dysregulation and neuroinflammatory processes. This review also evaluates the use of neuroimaging techniques in studying neuro-vulnerability and their potential applications in clinical settings. Furthermore, the association between neuro-vulnerability and eating disorders, as well as its contribution to obesity, is examined. Potential therapeutic interventions targeting neuro-vulnerability, including pharmacological treatments and lifestyle modifications, are reviewed. In conclusion, understanding the concept of neuro-vulnerability in energy metabolism regulation is crucial for addressing metabolic disorders. This review provides valuable insights into the underlying neurobiological mechanisms and their implications for metabolic health. Targeting neuro-vulnerability holds promise for developing innovative strategies in the prevention and treatment of metabolic disorders, ultimately improving metabolic health outcomes.

Exploring effects of Simvastatin on coagulation mediators to alleviate the advancement of high cholesterol diet triggered neurodegeneration

The objectives of our study were to investigate the possible effect of Simvastatin in ameliorating high cholesterol diet (HCD)-induced neurodegeneration and to also investigate its possible action on coagulation mediators. In silico and in vitro studies were performed to evaluate the impact of Simvastatin on prime coagulation mediators. HCD was used to induce neuropathology in wistar rats and histopathological and immunohistochemical studies were performed to evaluate the efficacy of Simvastatin in preventing the advancement of neurodegeneration in obese rats. Biochemical analyses were used to estimate changes in lipid profile, oxidative stress, inflammatory and coagulation markers. Simvastatin showed good theoretical affinity to coagulation proteins, significantly reversed changes in inflammatory and coagulation biomarkers which were induced by HCD. Enhanced fibrinolytic activity of Simvastatin was revealed through in vitro analysis. Immunohistoanalysis showed raised level of Nrf2. Histopathological studies also supported neuroprotective potential of Simvastatin in HCD fed rats. Simvastatin demonstrated reduced hypercoagulation, enhanced fibrinolysis and reversed neurodegeneration in HCD exposed rats suggesting its potential role in preventing the progression of neurodegeneration in obesity.

NGF and Its Role in Immunoendocrine Communication during Metabolic Syndrome

Nerve growth factor (NGF) was the first neurotrophin described. This neurotrophin contributes to organogenesis by promoting sensory innervation and angiogenesis in the endocrine and immune systems. Neuronal and non-neuronal cells produce and secrete NGF, and several cell types throughout the body express the high-affinity neurotrophin receptor TrkA and the low-affinity receptor p75NTR. NGF is essential for glucose-stimulated insulin secretion and the complete development of pancreatic islets. Plus, this factor is involved in regulating lipolysis and thermogenesis in adipose tissue. Immune cells produce and respond to NGF, modulating their inflammatory phenotype and the secretion of cytokines, contributing to insulin resistance and metabolic homeostasis. This neurotrophin regulates the synthesis of gonadal steroid hormones, which ultimately participate in the metabolic homeostasis of other tissues. Therefore, we propose that this neurotrophin's imbalance in concentrations and signaling during metabolic syndrome contribute to its pathophysiology. In the present work, we describe the multiple roles of NGF in immunoendocrine organs that are important in metabolic homeostasis and related to the pathophysiology of metabolic syndrome.

The Generation of Nitric Oxide from Aldehyde Dehydrogenase-2: The Role of Dietary Nitrates and Their Implication in Cardiovascular Disease Management

Reduced bioavailability of the nitric oxide (NO) signaling molecule has been associated with the onset of cardiovascular disease. One of the better-known and effective therapies for cardiovascular disorders is the use of organic nitrates, such as glyceryl trinitrate (GTN), which increases the concentration of NO. Unfortunately, chronic use of this therapy can induce a phenomenon known as "nitrate tolerance", which is defined as the loss of hemodynamic effects and a reduction in therapeutic effects. As such, a higher dosage of GTN is required in order to achieve the same vasodilatory and antiplatelet effects. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a cardioprotective enzyme that catalyzes the bio-activation of GTN to NO. Nitrate tolerance is accompanied by an increase in oxidative stress, endothelial dysfunction, and sympathetic activation, as well as a loss of the catalytic activity of ALDH2 itself. On the basis of current knowledge, nitrate intake in the diet would guarantee a concentration of NO such as to avoid (or at least reduce) treatment with GTN and the consequent onset of nitrate tolerance in the course of cardiovascular diseases, so as not to make necessary the increase in GTN concentrations and the possible inhibition/alteration of ALDH2, which aggravates the problem of a positive feedback mechanism. Therefore, the purpose of this review is to summarize data relating to the introduction into the diet of some natural products that could assist pharmacological therapy in order to provide the NO necessary to reduce the intake of GTN and the phenomenon of nitrate tolerance and to ensure the correct catalytic activity of ALDH2.

The role of SCAMP5 in central nervous system diseases

OBJECTIVE

Secretory carrier membrane proteins (SCAMPs) constitute a group of membrane transport proteins in plants, insects and mammals. The mammalian genome contains five types of SCAMP genes, namely, SCAMP1-SCAMP5. SCAMPs participate in the vesicle cycling fusion of vesicles and cell membranes and play roles in regulating exocytosis and endocytosis, activating synaptic function and transmitting nerve signals. Among these proteins, SCAMP5 is highly expressed in the brain and has direct or indirect effects on the function of the central nervous system. This paper may allow us to better understand the role of SCAMP5 in the central nervous system diseases. SCAMP5 regulates membrane transport, controls the exocytosis of SVs and is related to secretion carrier and membrane function. In addition, SCAMP5 plays a major role in the normal maintenance of the physiological functions of nerve cells. This article summarizes the effects of SCAMP5 on nerve cell exocytosis, endocytosis and synaptic function, as well as the relationship between SCAMP5 and various neurological diseases, to better understand the role of SCAMP5 in the pathogenesis of neurological diseases.

METHODS

Through PubMed, this paper examined and analyzed the role of SCAMP5 in the central nervous system, as well as the relationship between SCAMP5 and various neurological diseases using the key terms "secretory carrier membrane proteins"," SCAMP5"," exocytosis"," endocytosis", "synaptic function", "central nervous system diseases" up to 01 March 2022.

RESULTS

SCAMP5 regulates membrane transport, controls the exocytosis of SVs and is related to secretion carrier and membrane function. In addition, SCAMP5 plays a major role in the normal maintenance of the physiological functions of nerve cells.

CONCLUSION

This article summarizes the effects of SCAMP5 on nerve cell exocytosis, endocytosis and synaptic function, as well as the relationship between SCAMP5 and various neurological diseases, to better understand the role of SCAMP5 in the pathogenesis of neurological diseases.

The Contribution of Gut Microbiota and Endothelial Dysfunction in the Development of Arterial Hypertension in Animal Models and in Humans

The maintenance of the physiological values of blood pressure is closely related to unchangeable factors (genetic predisposition or pathological alterations) but also to modifiable factors (dietary fat and salt, sedentary lifestyle, overweight, inappropriate combinations of drugs, alcohol abuse, smoking and use of psychogenic substances). Hypertension is usually characterized by the presence of a chronic increase in systemic blood pressure above the threshold value and is an important risk factor for cardiovascular disease, including myocardial infarction, stroke, micro- and macro-vascular diseases. Hypertension is closely related to functional changes in the endothelium, such as an altered production of vasoconstrictive and vasodilator substances, which lead to an increase in vascular resistance. These alterations make the endothelial tissue unresponsive to autocrine and paracrine stimuli, initially determining an adaptive response, which over time lead to an increase in risk or disease. The gut microbiota is composed of a highly diverse bacterial population of approximately 10¹⁴ bacteria. A balanced intestinal microbiota preserves the digestive and absorbent functions of the intestine, protecting from pathogens and toxic metabolites in the circulation and reducing the onset of various diseases. The gut microbiota has been shown to produce unique metabolites potentially important in the generation of hypertension and endothelial dysfunction. This review highlights the close connection between hypertension, endothelial dysfunction and gut microbiota.

Short cognitive screening in elderlies as a part of advanced pharmaceutical care in Slovak community pharmacies - The pilot study KOGNIMET-SK

The aim of this study is to evaluate the implementation of a simple, easy-to-use cognitive screening test in the pharmaceutical care of elderly patients (aged 60 years and over) in community pharmacies and to test whether cognitive decline is associated with metabolic syndrome (MetS).

Current research has reported the increasing prevalence of MetS with age and indicated a link between cardiovascular risk factors and impairment of cognitive functions. We hypothesized that the short cognitive test realised in pharmaceutical care in community pharmacies could help identify risk groups of patients with potential cognitive decline. Because of the increasing pressure on primary care, collaboration between community pharmacists and general practitioners is essential, especially in preventive programmes and regarding chronically ill patients.

The study included 222 elderly patients aged 60 years and over reached between February 2018 and February 2019 in 16 community pharmacies in Slovakia. Criteria for the classification of MetS were used, following the International Diabetes Federation Worldwide Definition of MetS (2005) for European populations. Cognitive performance was evaluated using the Slovak version of the Montreal Cognitive Assessment. The scale range of the MoCA test is 0–30 points, and the cut-off for cognitive impairment is ≤ 24 points.

Our outcomes show that the presence of metabolic syndrome only slightly contributes to the impairment of cognitive functions of patients receiving routine pharmaceutical care in community pharmacies. Cognitive assessment might be an important tool for identifying risk groups of patients that would benefit from a specific approach within the framework of pharmaceutical care.

Is Arsenic Exposure a Risk Factor for Metabolic Syndrome? A Review of the Potential Mechanisms

Exposure to arsenic in drinking water is a worldwide health problem. This pollutant is associated with increased risk of developing chronic diseases, including metabolic diseases. Metabolic syndrome (MS) is a complex pathology that results from the interaction between environmental and genetic factors. This condition increases the risk of developing type 2 diabetes, cardiovascular diseases, and cancer. The MS includes at least three of the following signs, central obesity, impaired fasting glucose, insulin resistance, dyslipidemias, and hypertension. Here, we summarize the existing evidence of the multiple mechanisms triggered by arsenic to developing the cardinal signs of MS, showing that this pollutant could contribute to the multifactorial origin of this pathology.

Elevated plasma levels of the appetite-stimulator ACBP/DBI in fasting and obese subjects

Eukaryotic cells release the phylogenetically ancient protein acyl coenzyme A binding protein (ACBP, which in humans is encoded by the gene DBI, diazepam binding inhibitor) upon nutrient deprivation. Accordingly, mice that are starved for one to two days and humans that undergo voluntary fasting for one to three weeks manifest an increase in the plasma concentration of ACBP/DBI. Paradoxically, ACBP/DBI levels also increase in obese mice and humans. Since ACBP/DBI stimulates appetite, this latter finding may explain why obesity constitutes a self-perpetuating state. Here, we present a theoretical framework to embed these findings in the mechanisms of weight control, as well as a bioinformatics analysis showing that, irrespective of the human cell or tissue type, one single isoform of ACBP/DBI (ACBP1) is preponderant (~90% of all DBI transcripts, with the sole exception of the testis, where it is ~70%). Based on our knowledge, we conclude that ACBP1 is subjected to a biphasic transcriptional and post-transcriptional regulation, explaining why obesity and fasting both are associated with increased circulating ACBP1 protein levels.