Exercise and Curcumin in Combination Improves Cognitive Function and Attenuates ER Stress in Diabetic Rats

Exercise rescues cognitive impairment through inhibiting the fibrinogen neuroinflammative pathway in diabetes

Fibrinogen is a pivotal factor in the activation of neuroinflammation and cognitive impairment. While exercise, especifically swimming, has demonstrated cognitive benefits, the molecular protective mechanisms orchestrated by exercise in response to blood-brain barrier (BBB) leakage in diabetes remain elusive. This study systematically investigates the impact of fibrinogen on neuroinflammation and the role of exercise in diabetic rats. Diabetic rats underwent an 8-week swimming exercise regimen, and subsequent assessments included changes in interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), astroglia activation, BBB permeability, and key epithelial tight junction proteins such as zona occludins (ZO)-1, Claudin-5, and matrix metalloproteinase-9 (MMP-9). Spatial learning and memory were evaluated using the Morris water maze test and the novel object recognition test. The study revealed that exercise significantly improved cognitive function, potentially by suppressing fibrinogen levels and astroglia activation. Intriguingly, heightened fibrinogen expression markedly attenuated the protective effects of exercise on BBB integrity. Fibrinogen emerged as a potential compromise to exercise protective effect by increasing expression levels of inflammatory factors IL-1β and TNF-α. In summary, our findings elucidate that fibrinogen may contribute to the deterioration of cognition and diminish the protective effects of exercise by amplifying the neuroinflammatory process through damaged BBB in diabetes.

Exploring the relationship between lipid metabolism and cognition in individuals living with stable-phase Schizophrenia: a small cross-sectional study using Olink proteomics analysis

BACKGROUND

Cognitive impairment is a core symptom of schizophrenia. Metabolic abnormalities impact cognition, and although the influence of blood lipids on cognition has been documented, it remains unclear. We conducted a small cross-sectional study to investigate the relationship between blood lipids and cognition in patients with stable-phase schizophrenia. Using Olink proteomics, we explored the potential mechanisms through which blood lipids might affect cognition from an inflammatory perspective.

METHODS

A total of 107 patients with stable-phase schizophrenia and cognitive impairment were strictly included. Comprehensive data collection included basic patient information, blood glucose, blood lipids, and body mass index. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and the MATRICS Consensus Cognitive Battery (MCCB). After controlling for confounding factors, we identified differential metabolic indicators between patients with mild and severe cognitive impairment and conducted correlation and regression analyses. Furthermore, we matched two small sample groups of patients with lipid metabolism abnormalities and used Olink proteomics to analyze inflammation-related differential proteins, aiming to further explore the association between lipid metabolism abnormalities and cognition.

RESULTS

The proportion of patients with severe cognitive impairment (SCI) was 34.58%. Compared to patients with mild cognitive impairment (MCI), those with SCI performed worse in the Attention/Alertness (t = 2.668, p = 0.009) and Working Memory (t = 2.496, p = 0.014) cognitive dimensions. Blood lipid metabolism indicators were correlated with cognitive function, specifically showing that higher levels of TG (r = -0.447, p < 0.001), TC (r = -0.307, p = 0.002), and LDL-C (r = -0.607, p < 0.001) were associated with poorer overall cognitive function. Further regression analysis indicated that TG (OR = 5.578, P = 0.003) and LDL-C (OR = 5.425, P = 0.001) may be risk factors for exacerbating cognitive impairment in individuals with stable-phase schizophrenia. Proteomics analysis revealed that, compared to individuals with stable-phase schizophrenia and normal lipid metabolism, those with hyperlipidemia had elevated levels of 10 inflammatory proteins and decreased levels of 2 inflammatory proteins in plasma, with these changes correlating with cognitive function. The differential proteins were primarily involved in pathways such as cytokine-cytokine receptor interaction, chemokine signaling pathway, and IL-17 signaling pathway.

CONCLUSION

Blood lipids are associated with cognitive function in individuals with stable-phase schizophrenia, with higher levels of TG, TC, and LDL-C correlating with poorer overall cognitive performance. TG and LDL-C may be risk factors for exacerbating cognitive impairment in these patients. From an inflammatory perspective, lipid metabolism abnormalities might influence cognition by activating or downregulating related proteins, or through pathways such as cytokine-cytokine receptor interaction, chemokine signaling pathway, and IL-17 signaling pathway.

Curcumin: A Golden Approach to Healthy Aging: A Systematic Review of the Evidence

Aging-related disorders pose significant challenges due to their complex interplay of physiological and metabolic factors, including inflammation, oxidative stress, and mitochondrial dysfunction. Curcumin, a natural compound with potent antioxidant and anti-inflammatory properties, has emerged as a promising candidate for mitigating these age-related processes. However, gaps in understanding the precise mechanisms of curcumin's effects and the optimal dosages for different conditions necessitate further investigation. This systematic review synthesizes current evidence on curcumin's potential in addressing age-related disorders, emphasizing its impact on cognitive function, neurodegeneration, and muscle health in older adults. By evaluating the safety, efficacy, and mechanisms of action of curcumin supplementation, this review aims to provide insights into its therapeutic potential for promoting healthy aging. A systematic search across three databases using specific keywords yielded 2256 documents, leading to the selection of 15 clinical trials for synthesis. Here, we highlight the promising potential of curcumin as a multifaceted therapeutic agent in combating age-related disorders. The findings of this review suggest that curcumin could offer a natural and effective approach to enhancing the quality of life of aging individuals. Further research and well-designed clinical trials are essential to validate these findings and optimize the use of curcumin in personalized medicine approaches for age-related conditions.

The Role of Endoplasmic Reticulum Stress in Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD), which is involved in osteogenic reprogramming of valvular interstitial cells, is the most common form of valve disease. It still lacks effective pharmacologic intervention, as its cellular biological mechanisms remain unclear. Congenital abnormality (bicuspid valve) and older age are considered to be the most powerful risk factors for CAVD. Aortic valve sclerosis (AVS) and calcific aortic stenosis (CAS), 2 subclinical forms of CAVD, represent 2 distinct stages of aortic valve calcification. During the AVS stage, the disease is characterised by endothelial activation/damage, inflammatory response, and lipid infiltration accompanied by microcalcification. The CAS stage is dominated by calcification, resulting in valvular dysfunction and severe obstruction to cardiac outflow, which is life threatening if surgery is not performed in time. Endoplasmic reticulum (ER) stress, a state in which conditions disrupting ER homeostasis cause an accumulation of unfolded and misfolded proteins in the ER lumen, has been shown to promote osteogenic differentiation and aortic valve calcification. Therefore, identifying targets or drugs for suppressing ER stress may be a novel approach for CAVD treatment.

Curcumin: Overview of Extraction Methods, Health Benefits, and Encapsulation and Delivery Using Microemulsions and Nanoemulsions

Curcumin is the principal curcuminoid found in the rhizomes of turmeric. Due to its therapeutic action against cancer, depression, diabetes, some bacteria, and oxidative stress, it has been used widely in medicine since ancient times. Due to its low solubility, the human organism cannot completely absorb it. Advanced extraction technologies, followed by encapsulation in microemulsion and nanoemulsion systems, are currently being used to improve bioavailability. This review discusses the different methods available for curcumin extraction from plant material, methods for the identification of curcumin in the resulting extracts, its beneficial effects on human health, and the encapsulation techniques into small colloidal systems that have been used over the past decade to deliver this compound.

Caffeine protects against hippocampal alterations in type 2 diabetic rats via modulation of gliosis, inflammation and apoptosis

Type 2 diabetes (T2D) is implicated in the injury of several organs, including the brain resulting in neuronal damage, which may lead to cognitive impairment and dementia. Additionally, it is linked to inflammation, cytokine release, apoptosis and various degenerative conditions. Astrocytes and microglia might have a role in mediating these processes. Caffeine, a psychoactive beverage, has been shown to reduce the risk of cognitive and memory impairment. This study proposes anti-inflammatory and anti-apoptotic role of caffeine, which can be mediated via microglia/astrocyte activation and overexpression of pro-inflammatory molecules. T2D was induced in rats by feeding with high fat high sugar diet and injecting a single low dose streptozotocin (STZ) intraperitoneally. Other diabetic rats were given caffeine orally (in two doses) for 5 weeks, starting 1 week before STZ injection. Measurement of plasma cytokines, TNFα and IL6, was performed using enzyme-linked immunosorbent assay (ELISA) technique. After sacrificing animals, brains were obtained and processed for histological evaluation. Immunohistochemistry was also performed using the following primary antibodies, anti-astrocyte marker GFAP, anti-microglia marker CD11b and apoptotic marker (anti-cleaved caspase-3). There was upregulation of IL6 and TNF-α in diabetic rats. Additionally, histological evaluation of the hippocampus of diabetic rats revealed cellular degeneration. There was increased immunostaining of GFAP, CD11b and cleaved caspase-3 in diabetic rats. Pretreatment with caffeine to diabetic rats, resulted in improvement of structural changes and decrease in cytokine levels and immuno-markers, expression, and this was in a dose-dependent manner. In conclusion, caffeine had an ameliorative role in enhancing hippocampal degenerative changes in T2D.

Combined Physical Exercise and Diet: Regulation of Gut Microbiota to Prevent and Treat of Metabolic Disease: A Review

BACKGROUND

Unhealthy diet and sedentary lifestyle have contributed to the rising incidence of metabolic diseases, which is also accompanied by the shifts of gut microbiota architecture. The gut microbiota is a complicated and volatile ecosystem and can be regulated by diet and physical exercise. Extensive research suggests that diet alongside physical exercise interventions exert beneficial effects on metabolic diseases by regulating gut microbiota, involving in the changes of the energy metabolism, immune regulation, and the microbial-derived metabolites.

OBJECTIVE

In this review, we present the latest evidence in the modulating role of diet and physical exercise in the gut microbiota and its relevance to metabolic diseases. We also summarize the research from animal and human studies on improving metabolic diseases through diet-plus-exercise interventions, and new targeted therapies that might provide a better understanding of the potential mechanisms.

METHODS

A systematic and comprehensive literature search was performed in PubMed/Medline and Web of Science in October 2022. The key terms used in the searches included "combined physical exercise and diet", "physical exercise, diet and gut microbiota", "physical exercise, diet and metabolic diseases" and "physical exercise, diet, gut microbiota and metabolic diseases".

CONCLUSIONS

Combined physical exercise and diet offer a more efficient approach for preventing metabolic diseases via the modification of gut microbiota, abating the burden related to longevity.

Obese mice induced by high-fat diet have differential expression of circular RNAs involved in endoplasmic reticulum stress and neuronal synaptic plasticity of hippocampus leading to obesity-associated cognitive impairment

Obesity induced by a high-fat diet (HFD) is an important cause of impaired memory and cognitive function, but the underlying mechanisms are not clear. In the present study, we analyzed the levels of circRNAs in the hippocampus of C57BL/6J mice and evaluated the memory and cognition ability of C57BL/6J mice with HFD using Morris water maze and Y-maze approaches to explore the potential mechanisms linking circRNAs in obesity-associated cognitive impairment. Learning performance showed that HFD-induced obesity mice have impaired memory and cognition. The Arraystar analysis of the hippocampus displayed that HFD-induced obesity leads to the differential expression of circRNAs (DE-circRNAs) in mice. In total, 46 circular RNAs with elevated expression and 10 with decreased expression were identified. Among them, mmu_circRNA_004797 was identified to be significantly downregulated and the expression of mmu_circRNA_21040 was significantly upregulated in the HFD-fed mice, compared with control mice by PCR test. Bioinformatics analysis also showed that the upregulated circRNAs were related to the neuronal function and behavior, and material transport process, while downregulated circRNAs participated in the process of cell response to external stimuli, such as cellular response to nutrient levels. Furthermore, the KEGG pathway analysis showed that the upregulated circRNAs are mainly involved in Axon guidance, calcium signaling pathway, and ErbB signaling pathway. Only a single significant pathway, that is, “protein processing in endoplasmic reticulum”, was observed in the downregulated circRNAs. Finally, we examined the deficits of hippocampal synaptic plasticity and detected the expression of ER stress-related protein. The results showed that ER stress was activated in the hippocampus, and hippocampal synaptic plasticity deficits were displayed. Our results demonstrated that circRNAs were most likely implicated in the predisposition to obesity-associated cognitive impairment.

Tetramethylpyrazine Attenuates Cognitive Impairment Via Suppressing Oxidative Stress, Neuroinflammation, and Apoptosis in Type 2 Diabetic Rats

Cognitive dysfunction is an important complication observed in type 2 diabetes mellitus (T2DM) patients. Tetramethylpyrazine (TMP) is known to exhibit anti-diabetic and neuroprotective properties. Therefore, the present study aimed to investigate the possible therapeutic effects of TMP against type 2 diabetes-associated cognitive impairment in rats. High-fat diet (HFD) followed by a low dose of streptozotocin (35 mg/kg) was used to induce diabetes in Sprague-Dawley rats. TMP (20, 40, and 80 mg/kg) and Pioglitazone (10 mg/kg) were administered for 4 weeks. The Morris water maze (MWM) and novel objective recognition task (NOR) tests were used to assess memory function. Fasting blood glucose (FBG), lipid profile, HOMA-IR, glycosylated hemoglobin (HbA1c), and glucose tolerance were measured. Acetylcholinesterase (AChE) and choline acetytransferase (ChAT) activity, acetylcholine (ACh) levels, oxidative stress, apoptotic (Bcl-2, Bax, caspase-3), and inflammatory markers (TNF-α, IL-1β, and NF-kβ) were assessed. BDNF, p-AKT, and p-CREB levels were also measured. In the present work, we observed that treatment of diabetic rats with TMP alleviated learning and memory deficits, improved insulin sensitivity, and attenuated hyperglycemia and dyslipidemia. Furthermore, treatment with TMP increased BDNF, p-Akt, and p-CREB levels, normalized cholinergic dysfunction, and suppressed oxidative, inflammatory, and apoptotic markers in the hippocampus. Collectively, our results suggest that the TMP may be an effective neuroprotective agent in alleviating type 2 diabetes-associated cognitive deficits.

ER stress in obesity pathogenesis and management

Given the unprecedented global pandemic of obesity, a better understanding of the etiology of adiposity will be necessary to ensure effective management of obesity and related complications. Among the various potential factors contributing to obesity, endoplasmic reticulum (ER) stress refers to a state of excessive protein unfolding or misfolding that is commonly found in metabolic diseases including diabetes mellitus, insulin resistance (IR), and non-alcoholic fatty liver disease, although its role in obesogenesis remains controversial. ER stress is thought to drive adiposity by dampening energy expenditure, making ER stress a likely therapeutic target for the management of obesity. We summarize the role of ER stress and the ER stress response in the onset and development of obesity, and discuss the underlying mechanisms involved with a view to identifying novel therapeutic strategies for obesity prevention and management.

Endoplasmic Reticulum Stress in Chemotherapy-Induced Peripheral Neuropathy: Emerging Role of Phytochemicals

Chemotherapy-induced peripheral neuropathy (CIPN) is a significant dose-limiting long-term sequela in cancer patients undergoing treatment, often leading to discontinuation of treatment. No established therapy exists to prevent and/or ameliorate CIPN. Reactive oxygen species (ROS) and mitochondrial dysregulation have been proposed to underlie the pathobiology of CIPN. However, interventions to prevent and treat CIPN are largely ineffective. Additional factors and mechanism-based targets need to be identified to develop novel strategies to target CIPN. The role of oxidative stress appears to be central, but the contribution of endoplasmic reticulum (ER) stress remains under-examined in the pathobiology of CIPN. This review describes the significance of ER stress and its contribution to CIPN, the protective role of herbal agents in countering ER stress in nervous system-associated disorders, and their possible repurposing for preventing CIPN.

Curcumin in Combination with Aerobic Exercise Improves Follicular Dysfunction via Inhibition of the Hyperandrogen-Induced IRE1α/XBP1 Endoplasmic Reticulum Stress Pathway in PCOS-Like Rats

Combining diet with exercise can improve health and performance. Exercise can reduce androgen excess and insulin resistance (IR) in polycystic ovary syndrome (PCOS) patients. Curcumin is also presumed to improve the follicle development disorder. Here, we investigated the effects of a combination therapy of oral intake of curcumin and exercise on hyperandrogen-induced endoplasmic reticulum (ER) stress and ovarian granulosa cell (GC) apoptosis in rats with PCOS. We generated a PCOS model via continuous dehydroepiandrosterone subcutaneous injection into the necks of Sprague Dawley rats for 35 days. PCOS-like rats then received curcumin treatment combined with aerobic (treadmill) exercise for 8 weeks. We found that compared to control rats, the ovarian tissue and ovarian GCs of hyperandrogen-induced PCOS rats showed increased levels of ER stress-related genes and proteins. Hyperandrogen-induced ovarian GC apoptosis, which was mediated by excessive ER stress and unfolded protein response (UPR) activation, could cause follicle development disorders. Both curcumin gavage and aerobic exercise improved ovarian function via inhibiting the hyperandrogen-activated ER stress IRE1α-XBP1 pathway. Dihydrotestosterone- (DHT-) induced ER stress was mitigated by curcumin/irisin or 4μ8C (an ER stress inhibitor) in primary GC culture. In this in vitro model, the strongly expressed follicular development-related genes Ar, Cyp11α1, and Cyp19α1 were also downregulated.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.

Effects of physical exercise on memory in type 2 diabetes: a brief review

Type 2 diabetes (T2D) is a metabolic disorder that can lead to memory impairment. T2D main features are insulin resistance and hyperglycemia. Physical exercise is a non-pharmacological intervention that can regulate glycemic levels and fight insulin resistance in T2D, but whether it influences memory has been discussed. There are 2 main types of physical exercise: aerobic exercise and resistance exercise. Here, we review about the consequences of different physical exercise protocols on memory in diabetic subjects and animal models of T2D. Physical exercise, aerobic or resistance training, most of the times, is a capable agent to prevent and treat memory loss on diabetic subjects and animal models of T2D. However, whether aerobic and resistance training combined improve memory in subjects with T2D remains controversial. Regarding animal models of T2D, aerobic and resistance training have been showed to be capable to prevent and treat memory loss. Acute and chronic protocols of exercise, generally, induce positive physiological responses and adaptations in T2D, such as a better glucose control. The ideal physical exercise protocol that will produce the best benefits to diabetic subjects and to animal models of T2D has not been described yet. A variety of combination between intensity, volume, frequency, and duration of the physical exercise protocol on future studies is necessary to both diabetic subjects and animal models of T2D to determine the best protocol that will induce more benefits on memory in T2D.

Endoplasmic reticulum stress and unfolded protein response in cardiovascular diseases

Cardiovascular diseases (CVDs), such as ischaemic heart disease, cardiomyopathy, atherosclerosis, hypertension, stroke and heart failure, are among the leading causes of morbidity and mortality worldwide. Although specific CVDs and the associated cardiometabolic abnormalities have distinct pathophysiological and clinical manifestations, they often share common traits, including disruption of proteostasis resulting in accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER). ER proteostasis is governed by the unfolded protein response (UPR), a signalling pathway that adjusts the protein-folding capacity of the cell to sustain the cell's secretory function. When the adaptive UPR fails to preserve ER homeostasis, a maladaptive or terminal UPR is engaged, leading to the disruption of ER integrity and to apoptosis. ER stress functions as a double-edged sword, with long-term ER stress resulting in cellular defects causing disturbed cardiovascular function. In this Review, we discuss the distinct roles of the UPR and ER stress response as both causes and consequences of CVD. We also summarize the latest advances in our understanding of the importance of the UPR and ER stress in the pathogenesis of CVD and discuss potential therapeutic strategies aimed at restoring ER proteostasis in CVDs.

Animal Models of Metabolic Disorders in the Study of Neurodegenerative Diseases: An Overview

The incidence of metabolic disorders, as well as of neurodegenerative diseases—mainly the sporadic forms of Alzheimer’s and Parkinson’s disease—are increasing worldwide. Notably, obesity, diabetes, and hypercholesterolemia have been indicated as early risk factors for sporadic forms of Alzheimer’s and Parkinson’s disease. These conditions share a range of molecular and cellular features, including protein aggregation, oxidative stress, neuroinflammation, and blood-brain barrier dysfunction, all of which contribute to neuronal death and cognitive impairment. Rodent models of obesity, diabetes, and hypercholesterolemia exhibit all the hallmarks of these degenerative diseases, and represent an interesting approach to the study of the phenotypic features and pathogenic mechanisms of neurodegenerative disorders. We review the main pathological aspects of Alzheimer’s and Parkinson’s disease as summarized in rodent models of obesity, diabetes, and hypercholesterolemia.

Treadmill exercise mitigates neuroinflammation and increases BDNF via activation of SIRT1 signaling in a mouse model of T2DM

Although previous studies showed that exercise can improve cognitive dysfunction in type 2 diabetes (T2DM), the underlying mechanism remains unclear. Sirtuin 1 (SIRT1) has been shown to play a role in regulating inflammatory responses in the brain and increasing BDNF expression. This study investigated the effects of treadmill exercise on the hippocampal inflammatory response and BDNF expression in a T2DM mice model. We also tested whether these effects are SIRT1-dependent. In this study, C57BL/ 6 mice were used to construct T2DM model by a high-fat diet and STZ injection. We found that treadmill exercise for 8 weeks can significantly improve the cognitive dysfunction, alleviate activation of proinflammatory microglia M1 (Iba1 labeling) in the hippocampus of T2DM mice, and reduce the levels of proinflammatory factors IL-1β, IL-6, TNF-α, increase the expression levels of anti-inflammatory factors IL-10, TGF-β1, and promote the release of BDNF. We also found that exercise activate the signaling pathway of SIRT1/ NF-κB and SIRT1/ PGC-1α/ FNDC5/ BDNF. After the application of nicotinamide (NAM, SIRT1 inhibitor), the positive effects of exercise were remarkably suppressed. Our results showed that long-term moderate intensity treadmill exercise can alleviate inflammatory response in the hippocampus and increase BDNF expression in T2DM mice by activating SIRT1.