Rosa canina L. improves learning and memory-associated cognitive impairment by regulating glucose levels and reducing hippocampal insulin resistance in high-fat diet/streptozotocin-induced diabetic rats

Effects of exogenous ghrelin treatment on oxidative stress, inflammation and histological parameters in a fat-fed streptozotocin rat model

In this study, the anti-inflammatory, antioxidative, and protective effects of ghrelin were investigated in a fat-fed streptozotocin (STZ) rat model and compared with metformin, diabetes and the healthy control groups. Histopathological evaluations were performed on H&E-stained pancreas and brain sections. Biochemical parameters were investigated by enzyme-linked immunosorbent assay. Blood glucose levels were significantly decreased with ghrelin or metformin treatments than the diabetes group. STZ administration increased brain, renal and pancreatic IL-1β, TNF-α and MDA while decreasing GPX, CAT, SOD, and NGF levels. Ghrelin increased renal GPX, CAT, NGF pancreatic GPX, SOD, CAT, NGF and brain SOD, NGF while it decreased renal, pancreatic and brain IL-1β, TNF-α and MDA levels. Ghrelin reduced neuronal loss and degeneration in the cerebral cortex and hippocampus and greatly ameliorated diabetes-related damage in pancreas. In conclusion, the data suggested that ghrelin is an effective candidate as a protectant for reducing the adverse effects of diabetes.

Lactobacillus casei Zhang prevents hippocampal atrophy and cognitive impairment in rats with type 2 diabetes by regulating blood glucose levels

PURPOSE

Lactobacillus casei Zhang (LCZ) has health benefits, such as the ability to improve blood glucose levels in individuals with type 2 diabetes mellitus (T2DM). However, little is known about the effects of LCZ on brain structural plasticity and cognitive function in T2DM. The aims of this study were to determine whether LCZ can prevent and alleviate brain damage and memory impairment in T2DM, and to understand the mechanisms underlying the effects of LCZ in T2DM.

METHODS

Forty-one male Sprague-Dawley rats were divided into the saline control (CON, n = 14), T2DM (n = 14) and T2DM + LCZ (n = 13) groups. Magnetic resonance imaging (MRI) was used to evaluate alterations in brain structure among these three groups. The novel object recognition and Y-maze tests were conductedto assess cognitive function. Histological and immunohistochemical analysis, including Nissl staining, Golgi-Cox staining and glial fibrillary acidic protein immunostaining, were performed to explore the pathophysiological mechanisms underlying brain structural changes.

RESULTS

T2DM rats presented hyperglycemia, cognitive decline, hippocampal atrophy, and damage to hippocampal neurons and astrocytes. Compared with those in the T2DM groups, rats in the T2DM + LCZ group presented lower blood glucose levels, better cognitive function, a larger hippocampal volume, and more normal hippocampal neurons and astrocytes. There was no significant difference in these metrics between rats in the T2DM + LCZ and CON groups.

CONCLUSION

Hyperglycemia-induced damage to hippocampal neurons and astrocytes may lead to hippocampal atrophy and cognitive dysfunction in T2DM. LCZ can effectively prevent this damage by regulating blood glucose levels, preventing brain atrophy and cognitive impairment in T2DM rats. These findings provide a scientific basis for the clinical application of LCZ.

Following changes in brain structure and function with multimodal MRI in a year-long prospective study on the development of Type 2 diabetes

Aims

To follow disease progression in a rat model of Type 2 diabetes using multimodal MRI to assess changes in brain structure and function.

Material and methods

Female rats (n = 20) were fed a high fat/high fructose diet or lab chow starting at 90 days of age. Diet fed rats were given streptozotocin to compromise pancreatic beta cells, while chow fed controls received vehicle. At intervals of 3, 6, 9, and 12 months, rats were tested for changes in behavior and sensitivity to pain. Brain structure and function were assessed using voxel based morphometry, diffusion weighted imaging and functional connectivity.

Results

Diet fed rats presented with elevated plasma glucose levels as early as 3 months and a significant gain in weight by 6 months as compared to controls. There were no significant changes in cognitive or motor behavior over the yearlong study but there was a significant increase in sensitivity to peripheral pain in diet fed rats. There were region specific decreases in brain volume e.g., basal ganglia, thalamus and brainstem in diet fed rats. These same regions showed elevated measures of water diffusivity evidence of putative vasogenic edema. By 6 months, widespread hyperconnectivity was observed across multiple brain regions. By 12 months, only the cerebellum and hippocampus showed increased connectivity, while the hypothalamus showed decreased connectivity in diet fed rats.

Conclusions

Noninvasive multimodal MRI identified site specific changes in brain structure and function in a yearlong longitudinal study of Type 2 diabetes in rats. The identified diabetic-induced neuropathological sites may serve as biomarkers for evaluating the efficacy of novel therapeutics.

Gender Differences in Dendritic Damage, Gut Microbiota Dysbiosis, and Cognitive Impairment During Aging Processes

BACKGROUND

Cognitive impairment is a common and feared characteristic of aging processes, and one key mechanism of cognition is hippocampal synaptic structure. Previous studies have reported that gut microbiota dysbiosis occurred in neurodegenerative diseases and other brain disorders with cognitive impairment. However, it is not clear how gender differences affect cognitive impairment in aging processes and whether they affect synaptic structure and gut microbiota. Here, we studied the gender differences in cognitive ability, dendritic morphology, and gut microbiota of adult, middle-, and old-aged rats.

METHODS

The cognitive ability of rats using was assessed by the Y-maze SAB test, the light/dark discrimination test, and the MWM test. Dendritic morphology was investegated by Golgi staining. Microbiota composition, diversity and richness were analyzed by 16S rRNA gene sequencing.

RESULTS

The results showed that the cognitive ability of old-aged rats was decreased than adult and middle-aged rats in the spontaneous alternation behavior test, the light/dark discrimination test in Y-maze, and the MWM test; males have better cognitive ability than the females for middle-aged rats. The neuronal dendritic structures of CA1, CA3, and DG regions of the hippocampus were damaged to different degrees during aging, and the spine loss of females was more than that of males in CA1 and CA3 of middle-aged rats. In addition, the microbial diversity of gut microbiota was significantly decreased in old-aged male rats; the distribution and composition of microbiota communities were different between male and female rats at different ages.

CONCLUSION

These findings revealed that cognitive impairment in aged rats might result from dendritic damage in the hippocampus and gut microbiota dysbiosis, which provides direct evidence that gender differences in dendritic damage and gut microbiota dysbiosis might associate with cognitive impairment in naturally aged rats.

Diabetes and vascular mild cognitive impairment among Chinese ≥50 years: A cross-sectional study with 2020 participants

BACKGROUND

With the decline of cognitive function in vascular cognitive impairment, the burden on the family and society will increase. Therefore, early identification of vascular mild cognitive impairment (VaMCI) is crucial. The focus of early identification of VaMCI is on the attention of risk factors. Therefore, this study aimed to investigate the relationship between diabetes and VaMCI among the Chinese, hoping to predict the risk of VaMCI by diabetes and to move the identification of vascular cognitive impairment forward.

METHODS

We collected data from seven clinical centers and nine communities in China. All participants were over 50 years of age and had cognitive complaints. We collected basic information of the participants, and cognitive function was professionally assessed by the Montreal Cognitive Assessment scale. Finally, logistic regression analysis was used to analyze the correlation between each factor and VaMCI.

RESULTS

A total of 2020 participants were included, including 1140 participants with VaMCI and 880 participants with normal cognition. In univariate logistic regression analysis, age, heavy smoking, and diabetes had a positive correlation with VaMCI. At the same time, being married, high education, and light smoking had a negative correlation with VaMCI. After correction, only diabetes (OR = 1.04, 95% CI: 1.01-1.09, p = 0.05) had a positive correlation with VaMCI, and high education (OR = 0.60, 95% CI:.45-.81, p = 0.001) had a negative correlation with VaMCI.

CONCLUSION

In our study, we found that diabetes had a positive correlation with VaMCI, and high education had a negative correlation with VaMCI. Therefore, early identification and timely intervention of diabetes may reduce the risk of VaMCI and achieve early prevention of VaMCI.

Design and in vitro evaluation of curcumin-loaded PLGA nanoparticle-embedded sodium alginate/gelatin 3D printed scaffolds for Alzheimer's disease

BACKGROUND

Targeted nanoparticles (NPs) are aimed at improving clinical outcomes by enhancing the diagnostic and therapeutic efficacy of drugs in the treatment of Alzheimer's disease (AD).

METHODS

Curcumin (CUR)-loaded poly-lactic-co-glycolic acid (PLGA) NPs (CNPs) were produced to demonstrate a prolonged release and successfully embedded into 3D printed sodium alginate (SA)/gelatin (GEL) scaffolds that can dissolve rapidly sublingually. Characterization and in vitro activity of the NPs and scaffolds were evaluated.

RESULTS

Based on the in vitro drug release studies, 99.6 % of the encapsulated CUR was released in a controlled manner within 18 days for the CNPs. In vitro cell culture studies showed that all samples exhibited cell viability above 84.2 % and no significant cytotoxic effect on SH-SY5Y cells. The samples were analyzed through 2 different pathways by PCR analysis. Real-time PCR results indicated that CNP and CNP-embedded SA/GEL scaffolds (CNPSGS) may show neuroprotective effects by modulating the Wnt/β-catenin pathway. The gene expression level of β-catenin slightly increased compared to the gene expression levels of other proteins and enzymes with these treatments. However, the PI3K/Akt/GSK-3β signaling pathway was regulated at the same time because of the crosstalk between these 2 pathways.

CONCLUSION

CNPSGS might be an effective therapeutic alternative for AD treatment.

Sublingual Administration of Teucrium Polium-Loaded Nanofibers with Ultra-Fast Release in the Treatment of Diabetes Mellitus: In Vitro and In Vivo Evaluation

In this study, Teucrium polium (TP) methanolic extract, which has antidiabetic activity and protects the β-cells of the pancreas, was loaded in polyethylene oxide/sodium alginate nanofibers by electrospinning and administered sublingually to evaluate their effectiveness in type-2 diabetes mellitus (T2DM) by cell culture and in vivo studies. The gene expressions of insulin, glucokinase, GLUT-1, and GLUT-2 improved in TP-loaded nanofibers (TPF) on human beta cells 1.1B4 and rat beta cells BRIN-BD11. Fast-dissolving (<120 s) sublingual TPF exhibited better sustainable anti-diabetic activity than the suspension form, even in the twenty times lower dosage in streptozotocin/nicotinamide-induced T2DM rats. The levels of GLP-1, GLUT-2, SGLT-2, PPAR-γ, insulin, and tumor necrosis factor-alpha were improved. TP and TPF treatments ameliorated morphological changes in the liver, pancreas, and kidney. The fiber diameter increased, tensile strength decreased, and the working temperature range enlarged by loading TP in fibers. Thus, TPF has proven to be a novel supportive treatment approach for T2DM with the features of being non-toxic, easy to use, and effective.

Cognitive impairment after long COVID-19: current evidence and perspectives

COVID-19, caused by the SARS-CoV-2 virus, is a respiratory infectious disease. While most patients recover after treatment, there is growing evidence that COVID-19 may result in cognitive impairment. Recent studies reveal that some individuals experience cognitive deficits, such as diminished memory and attention, as well as sleep disturbances, suggesting that COVID-19 could have long-term effects on cognitive function. Research indicates that COVID-19 may contribute to cognitive decline by damaging crucial brain regions, including the hippocampus and anterior cingulate cortex. Additionally, studies have identified active neuroinflammation, mitochondrial dysfunction, and microglial activation in COVID-19 patients, implying that these factors may be potential mechanisms leading to cognitive impairment. Given these findings, the possibility of cognitive impairment following COVID-19 treatment warrants careful consideration. Large-scale follow-up studies are needed to investigate the impact of COVID-19 on cognitive function and offer evidence to support clinical treatment and rehabilitation practices. In-depth neuropathological and biological studies can elucidate precise mechanisms and provide a theoretical basis for prevention, treatment, and intervention research. Considering the risks of the long-term effects of COVID-19 and the possibility of reinfection, it is imperative to integrate basic and clinical research data to optimize the preservation of patients' cognitive function and quality of life. This integration will also offer valuable insights for responding to similar public health events in the future. This perspective article synthesizes clinical and basic evidence of cognitive impairment following COVID-19, discussing potential mechanisms and outlining future research directions.