Mizagliflozin, a selective SGLT1 inhibitor, improves vascular cognitive impairment in a mouse model of small vessel disease

Oxidative stress and chronic cerebral hypoperfusion: An overview from preclinical rodent models

Chronic cerebral hypoperfusion (CCH) is an important clinical condition characterized by a prolonged reduction in cerebral blood flow that contributes to several neurodegenerative diseases, including vascular dementia and Alzheimer's disease. A number of rodent models of CCH have been developed that mimic the human pathological conditions of reduced cerebral perfusion. These models have been instrumental in elucidating the molecular and cellular mechanisms involved in CCH-induced brain damage. Oxidative stress is induced by perturbations in cellular pathways caused by CCH, including mitochondrial dysfunction, ion pump dysfunction, and adenosine triphosphate (ATP) depletion. The deleterious stress leads to the accumulation of reactive oxygen species (ROS) and exacerbates damage to neuronal structures, significantly impairing cognitive function. Among the various therapeutic strategies being evaluated, edaravone, a potent antioxidant, is emerging as a promising drug due to its neuroprotective properties against oxidative stress. Initially approved for use in ischemic stroke, research using rodent CCH models has shown that edaravone has significant efficacy in scavenging free radicals and ameliorating oxidative stress-induced neuronal damage under CCH conditions. This mini-review summarizes the current literature on the rodent models of CCH and then discusses the therapeutic potential of edaravone to reduce neuronal and vascular damage caused by CCH-induced oxidative stress.

Mizagliflozin ameliorates diabetes induced kidney injury by inhibitor inhibit inflammation and oxidative stress

BACKGROUND

Mizagliflozin (MIZ) is a specific inhibitor of sodium-glucose cotransport protein 1 (SGLT1) originally developed as a medication for diabetes.

AIM

To explore the impact of MIZ on diabetic nephropathy (DN).

METHODS

Diabetic mice were created using db/db mice. They were administered either a low dose (0.5 mg/kg) or a high dose (1.0 mg/kg) of the SGLT1 inhibitor MIZ via stomach gavage for 8 weeks. Subsequently, mesangial cells (MCs) were isolated and subjected to high glucose conditions in culture to assess the effects of MIZ on DN.

RESULTS

The results showed that low doses of MIZ significantly reduced albuminuria to a level comparable to that achieved with high doses in db/db mice. High doses of MIZ led to a substantial increase in body weight in mice, along with decreased blood glucose levels and food intake. Moreover, the intervention with high-dose MIZ notably decreased the expression of extracellular matrix genes, such as collagen type 1 alpha 1 mRNA levels. While the expression of SGLT1 increased after exposure to high glucose, it decreased following treatment with MIZ. Furthermore, MIZ intervention was more effective in improving lactate dehydrogenase levels in MCs induced by high glucose compared to canagliflozin. MIZ also significantly elevated levels of antioxidant enzymes superoxide dismutase, catalase, and glutathione, while reducing malondialdehyde levels.

CONCLUSION

These findings indicate that MIZ can ameliorate DN by inhibiting SGLT1, inflammation, and oxidative stress.

SGLT1 contributes to glucose-mediated exacerbation of ischemia-reperfusion injury in ex vivo rat heart

Hyperglycaemia is common during acute coronary syndromes (ACS) irrespective of diabetic status and portends excess infarct size and mortality, but the mechanisms underlying this effect are poorly understood. We hypothesized that sodium/glucose linked transporter-1 (SGLT1) might contribute to the effect of high-glucose during ACS and examined this using an ex-vivo rodent heart model of ischaemia-reperfusion injury. Langendorff-perfused rat hearts were subjected to 35 min ischemia and 2 h reperfusion, with variable glucose and reciprocal mannitol given during reperfusion in the presence of pharmacological inhibitors of SGLT1. Myocardial SGLT1 expression was determined in rat by rtPCR, RNAscope and immunohistochemistry, as well as in human by single-cell transcriptomic analysis. High glucose in non-diabetic rat heart exacerbated reperfusion injury, significantly increasing infarct size from 45 ± 3 to 65 ± 4% at 11-22 mmol/L glucose, respectively (p < 0.01), an association absent in diabetic heart (32 ± 1-37 ± 5%, p = NS). Rat heart expressed SGLT1 RNA and protein in vascular endothelium and cardiomyocytes, with similar expression found in human myocardium by single-nucleus RNA-sequencing. Rat SGLT1 expression was significantly reduced in diabetic versus non-diabetic heart (0.608 ± 0.08 compared with 1.116 ± 0.13 probe/nuclei, p < 0.01). Pharmacological inhibitors phlorizin, canagliflozin or mizagliflozoin in non-diabetic heart revealed that blockade of SGLT1 but not SGLT2, abrogated glucose-mediated excess reperfusion injury. Elevated glucose is injurious to the rat heart during reperfusion, exacerbating myocardial infarction in non-diabetic heart, whereas the diabetic heart is resistant to raised glucose, a finding which may be explained by lower myocardial SGLT1 expression. SGLT1 is expressed in vascular endothelium and cardiomyocytes and inhibiting SGLT1 abrogates excess glucose-mediated infarction. These data highlight SGLT1 as a potential clinical translational target to improve morbidity/mortality outcomes in hyperglycemic ACS patients.

Sodium-glucose cotransporter 1/2 inhibition and risk of neurodegenerative disorders: A Mendelian randomization study

INTRODUCTION

This study aims to evaluate the effects of sodium-glucose cotransporter 1 inhibitors (SGLT1i) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) on neurodegenerative disorders and to investigate the role of hemoglobin A1c (HbA1c) levels.

METHODS

Utilizing drug target Mendelian randomization, we employed single nucleotide polymorphisms (SNPs) proximal to the SLC5A1 and SLC5A2 genes to analyze the influence of SGLT1i and SGLT2i on Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), frontotemporal dementia (FTD), Lewy body dementia (LBD), and amyotrophic lateral sclerosis (ALS), with type 2 diabetes (T2D) as a positive control. An additional analysis examined the impact of HbA1c levels on the same disorders.

RESULTS

SGLT1i exhibited a significant association with decreased risk for ALS and MS. Conversely, SGLT2i were linked to an increased risk of AD, PD, and MS. Elevated HbA1c levels, independent of SGLT1 and SGLT2 effects, were associated with an increased risk of PD. Sensitivity analyses supported the robustness of these findings.

CONCLUSION

Our study suggests that SGLT1i may confer protection against ALS and MS, whereas SGLT2i could elevate the risk of AD, PD, and MS. Additionally, elevated HbA1c levels emerged as a risk factor for PD. These findings underscore the importance of personalized approaches in the utilization of SGLT inhibitors, considering their varying impacts on the risks of neurodegenerative diseases.

Cognitive impairment in cerebral small vessel disease induced by hypertension

ABSTRACT

Hypertension is a primary risk factor for the progression of cognitive impairment caused by cerebral small vessel disease, the most common cerebrovascular disease. However, the causal relationship between hypertension and cerebral small vessel disease remains unclear. Hypertension has substantial negative impacts on brain health and is recognized as a risk factor for cerebrovascular disease. Chronic hypertension and lifestyle factors are associated with risks for stroke and dementia, and cerebral small vessel disease can cause dementia and stroke. Hypertension is the main driver of cerebral small vessel disease, which changes the structure and function of cerebral vessels via various mechanisms and leads to lacunar infarction, leukoaraiosis, white matter lesions, and intracerebral hemorrhage, ultimately resulting in cognitive decline and demonstrating that the brain is the target organ of hypertension. This review updates our understanding of the pathogenesis of hypertension-induced cerebral small vessel disease and the resulting changes in brain structure and function and declines in cognitive ability. We also discuss drugs to treat cerebral small vessel disease and cognitive impairment.

SGLT2 and SGLT1 inhibitors suppress the activities of the RVLM neurons in newborn Wistar rats

Hypertension is well-known to often coexist with diabetes mellitus (DM) in humans. Treatment with sodium-glucose cotransporter 2 (SGLT2) inhibitors has been shown to decrease both the blood glucose and the blood pressure (BP) in such patients. Some reports show that SGLT2 inhibitors improve the BP by decreasing the activities of the sympathetic nervous system. Therefore, we hypothesized that SGLT2 inhibitors might alleviate hypertension via attenuating sympathetic nervous activity. Combined SGLT2/SGLT1 inhibitor therapy is also reported as being rather effective for decreasing the BP. In this study, we examined the effects of SGLT2 and SGLT1 inhibitors on the bulbospinal neurons of the rostral ventrolateral medulla (RVLM). To investigate whether bulbospinal RVLM neurons are sensitive to SGLT2 and SGLT1 inhibitors, we examined the changes in the neuronal membrane potentials (MPs) of these neurons using the whole-cell patch-clamp technique during superfusion of the cells with the SGLT2 and SGLT1 inhibitors. A brainstem-spinal cord preparation was used for the experiments. Our results showed that superfusion of the RVLM neurons with SGLT2 and SGLT1 inhibitor solutions induced hyperpolarization of the neurons. Histological examination revealed the presence of SGLT2s and SGLT1s in the RVLM neurons, and also colocalization of SGLT2s with SGLT1s. These results suggest the involvement of SGLT2s and SGLT1s in regulating the activities of the RVLM neurons, so that SGLT2 and SGLT1 inhibitors may inactivate the RVLM neurons hyperpolarized by empagliflozin. SGLT2 and SGLT1 inhibitors suppressed the activities of the bulbospinal RVLM neurons in the brainstem-spinal preparations, suggesting the possibilities of lowering BP by decreasing the sympathetic nerve activities. RVLM, rostral ventrolateral medulla. IML, intralateral cell column. aCSF, artificial cerebrospinal fluid.

Research hotspots and trends of multimodality MRI on vascular cognitive impairment in recent 12 years: A bibliometric analysis

BACKGROUND

Multimodality magnetic resonance imaging (MRI) is widely used to detect vascular cognitive impairment (VCI). However, a bibliometric analysis of this issue remains unknown. Therefore, this study aimed to explore the research hotspots and trends of multimodality MRI on VCI over the past 12 years based on the Web of Science core collection using CiteSpace Software (6.1R2).

METHODS

Literature related to multimodality MRI for VCI from 2010 to 2021 was identified and analyzed from the Web of Science core collection database. We analyzed the countries, institutions, authors, cited journals, references, keyword bursts, and clusters using CiteSpace.

RESULTS

In total, 587 peer-reviewed documents were retrieved, and the annual number of publications showed an exponential growth trend over the past 12 years. The most productive country was the USA, with 182 articles, followed by China with 134 papers. The top 3 active academic institutions were Capital Medical University, Radboud UNIV Nijmegen, and UNIV Toronto. The most productive journal was the Journal of Alzheimer's Disease (33 articles). The most co-cited journal was Neurology, with the highest citations (492) and the highest intermediary centrality (0.14). The top-ranked publishing author was De Leeuw FE (17 articles) with the highest intermediary centrality of 0.04. Ward Law JM was the most cited author (123 citations) and Salat Dh was the most centrally cited author (0.24). The research hotspots of multimodal MRI for VCI include Alzheimer disease, vascular cognitive impairment, white matter intensity, cerebrovascular disease, dementia, mild cognitive impairment, neurovascular coupling, acute ischemic stroke, depression, and cerebral ischemic stroke. The main frontiers in the keywords are fMRI, vascular coupling, and cerebral ischemic stroke, and current research trends include impact, decline, and classification.

CONCLUSIONS

The findings from this bibliometric study provide research hotspots and trends for multimodality MRI for VCI over the past 12 years, which may help researchers identify hotspots and explore cutting-edge trends in this field.

Effect and Mechanism of Yisui Fuyongtang (YSFYT) Decoction on Cognitive Function and Synaptic Plasticity in Rats with Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) has emerged as the second major disease responsible for dementia, and there is still a lack of effective treatment methods for this disorder to date. Clinical medications have found that Yisui Fuyongtang (YSFYT) Decoction is effective in improving neurological signs and learning-memory functions in patients who develop white matter lesions and whole brain atrophy. To clarify the effect and molecular regulation mechanism of YSFYT Decoction on model rats, this research analyzed the influence of YSFYT Decoction on the learning-memory ability and lipid metabolism of rats based on behavioral and biochemical analysis. Further pathology and protein detection methods were adopted to investigate the action of YSFYT Decoction on the neurons in the hippocampus of model rats and the regulation of the brain derived neurotrophic factor (BDNF)-tyrosine protein kinase receptor B (TrkB) signaling pathway. Compared with the VCI group, after YSFYT Decoction administration, the ratio of swimming time in the platform, number of crossing the platform, number of active avoidance, and proportion of active avoidance of the rats were markedly increased, whereas the response latency was substantially reduced (p < 0.05). Biochemical tests indicated that contents of lipoprotein lipase (LPL), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) of the model rats in YSFYT Decoction treatment group were greatly reduced, whereas those of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), catalase (CAT), malondialdehyde (MDA), and superoxide dismutase (SOD) were elevated (p < 0.05). Additionally, Bcl-2 expression in YSFYT Decoction treatment group was significantly increased, but neuron apoptosis of the hippocampus tissue was reduced. Meanwhile, neuron number was apparently higher than that in VCI model group. Following Yisui Decoction treatment, expressions of growth-associated protein 43 (GAP43), synaptophysin (SYP), postsynaptic density 95 (PSD95), NMDAR subunit 2B (NR2B), BDNF, TrkB, phospho-mitogen-activated protein kinase (p-MAPK), extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), and phospho-protein kinase B (p-AKT) were markedly elevated. Taken together, YSFYT Decoction could activate the BDNF-TrkB signaling pathway, elevate Bcl-2 expression, and minimize neuronal apoptosis in hippocampus, thereby improving the behavioral characteristics and biochemical indicators of the VCI rat model.