Dapagliflozin diminishes memory and cognition impairment in Streptozotocin induced diabetes through its effect on Wnt/β-Catenin and CREB pathway

Inflammation levels in type 2 diabetes mellitus patients with mild cognitive impairment: Assessment followed by amelioration via dapagliflozin therapy

AIMS

To investigate systemic inflammation and the effect of dapagliflozin treatment in (type 2 diabetes mellitus) T2DM patients with mild cognitive impairment (MCI).

METHODS

Between January and December 2023, 200 participants were recruited from the Department of Endocrinology of Hefei First People's Hospital. Baseline data collected included medical history, fasting blood glucose, HbA1c, liver and kidney function, lipid profiles, IL-1β, TNF-α, sVCAM-1 level, and the urinary albumin-creatinine ratio (uACR). Based on their Montreal Cognitive Assessment Scale (MoCA) scores, these participants were categorized into two groups: 127 in the MCI group and 73 in the non-MCI group. MCI group received dapagliflozin (10 mg daily) alongside standard treatment.

RESULTS

The MCI group showed higher age, height, weight, BMI, HbA1c, FBG, disease duration, carotid plaques, stenosis rates, and elevated IL-1β, TNF-α, and sVCAM-1. MoCA scores were significantly lower in the MCI group. Correlation analysis showed a negative correlation of MoCA scores with IL-1β, TNF-α, sVCAM-1, plaques, stenosis, FBG, and HbA1c, and a positive correlation with height. Binary logistic regression identified age, BMI, IL-1β, sVCAM-1, and FBG as predictors of cognitive impairment in T2DM. Dapagliflozin treatment reduced BMI, HbA1c, inflammatory markers, and FBG, improving MoCA scores.

CONCLUSION

Dapagliflozin treatment may improve cognitive function by reducing inflammation.

Sodium-glucose cotransporter 2 inhibitor partially improves brain mitochondrial function, but does not mitigate cognitive impairment in rats with myocardial infarction

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are recommended to treat heart failure (HF) with the benefit of mitigating cognitive impairment in HF patients with type 2 diabetes. However, the underlying mechanisms are still unclear. This study aimed to investigate whether SGLT2i can improve cognitive function and synaptic plasticity in rats with myocardial infarction (MI) through attenuating inflammation, oxidative stress, impaired metabolism, and mitochondrial dysfunction in the brain. Male rats (n = 8/group) underwent either a sham operation or MI induced by permanent ligation of the left anterior descending coronary artery. MI rats with ejection fraction <50 % were divided into three groups to receive either a vehicle, SGLT2i (Dapagliflozin, 1 mg/kg), or angiotensin-converting enzyme inhibitor (Enalapril, 10 mg/kg, positive control) for four weeks. Cardiac function, cognitive function, synaptic plasticity, dendritic spine density, and brain biochemical changes were assessed at the end of the protocol. MI rats exhibited cardiac dysfunction, hippocampal-dependent cognitive impairment, impaired synaptic plasticity, and loss of dendritic spines. Brain oxidative stress, inflammation, and mitochondrial dysfunction were also observed in MI rats. Treatment with SGLT2i and ACEi improved cardiac function but failed to attenuate cognitive impairment, synaptic dysplasticity, and loss of dendritic spine density in MI rats. A decrease in brain glutamate level was found following MI, which can be restored by SGLT2i and ACEi. Only SGLT2i partially improved brain mitochondrial function. In summary, SGLT2i enhanced glutamate levels and partially improved mitochondrial function in the brain; however, these changes were insufficient to improve cognitive function in MI rats.

Dapagliflozin Ameliorate Type-2 Diabetes Associated Neuropathy via Regulation of IGF-1R Signaling

Dapagliflozin, an approved SGLT2 inhibitor, has been shown to have extra-glycemic effects like cardio-reno protection. However, the neuroprotective effects of SGLT2 inhibitors against diabetic neuropathy (DN) have not been explored. The current study aimed to determine the neuroprotective potential of Dapagliflozin against STZ-NAD-induced DN in Wistar rats via IGF-1 signaling. DN was induced by STZ-NAD in male Wistar rats. After 60 days of induction, behavioural tests were conducted to access DN, and treatment with Dapagliflozin (0.75 mg/kg & 1.50 mg/kg) was initiated for 30 days. At the end of the study, the brain and sciatic nerve were isolated and expression analysis of IGF-1R signaling molecules was carried out using western blotting, qRTPCR, and immunohistochemistry. Structural changes in the brain and sciatic nerve were ascertained by histopathology. The results showed that treatment with Dapagliflozin improved behavioural parameters in STZ-NAD-induced DN rats. The decreased expression levels of IGF1R signaling pathway molecules and increased expression of p-AKT were found to increase and decrease in the brain and sciatic nerve, respectively after the treatment. Histological studies demonstrated the restoration of normal architecture of the brain and sciatic nerve after treatment with dapagliflozin. The altered expression of IGF-1R signaling molecules established the neuroprotective potential of dapagliflozin against DN.

Canagliflozin attenuates neurodegeneration and ameliorates dyskinesia through targeting the NLRP3/Nurr1/GSK-3β/SIRT3 pathway and autophagy modulation in rotenone-lesioned rats

Despite a deep understanding of Parkinson's disease (PD) and levodopa-induced dyskinesia (LID) pathogenesis, current therapies are insufficient to effectively manage the progressive nature of PD or halt LID. Growing hypotheses suggested the NOD-like receptor 3 (NLRP3) inflammasome and orphan nuclear receptor-related 1 (Nurr1)/glycogen synthase kinase-3β (GSK-3β) and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α)/sirtuin 3 (SIRT3) pathways as potential avenues for halting neuroinflammation and oxidative stress in PD.

AIMS

This study investigated for the first time the neuroprotective effect of canagliflozin against PD and LID in rotenone-intoxicated rats, emphasizing the crosstalk among the NLRP3/caspase-1 cascade, PGC-1α/SIRT3 pathway, mammalian target of rapamycin (mTOR)/beclin-1, and Nurr1/β-catenin/GSK-3β pathways as possible treatment strategies in PD and LID. Also, correlating NLRP3 expression with all evaluated parameters.

MAIN METHODS

The PD rat model was induced via eleven rotenone (1.5 mg/kg) subcutaneous injections day after day. Canagliflozin (20 mg/kg) and/or L-dopa/carbidopa (100/25 mg/kg) were orally administered daily from the beginning until the end of the experiment.

KEY FINDINGS

Canagliflozin significantly improved neurobehavioral and histological assessments, whereas dyskinesia scores declined. The improvement was confirmed through tyrosine hydroxylase and β-catenin upregulation in contrast to NLRP3 and caspase-1 in substantia nigra pars compacta, as revealed immunohistochemically. In addition, canagliflozin induced a prominent elevation in dopamine, Nurr1, PGC-1α, SIRT3, and beclin-1, whereas mTOR and GSK-3β expressions were downregulated.

SIGNIFICANCE

Our results revealed the aspiring canagliflozin neuroprotective properties against PD and LID in rotenone-lesioned rats via the assumed anti-inflammatory activity and implication of NLRP3/caspase-1, Nurr1/GSK-3β/β-catenin, PGC-1α/SIRT3, and beclin-1/mTOR pathways.

The Promising Potency of Sodium-Glucose Cotransporter 2 Inhibitors in the Prevention of and as Treatment for Cognitive Impairment Among Type 2 Diabetes Patients

Type 2 diabetes mellitus (T2DM), accounting for the majority of diabetes mellitus prevalence, is associated with an increased risk of cognition decline and deterioration of cognition function in diabetic patients. The sodium-glucose cotransporter 2 (SGLT2), located in the renal proximal tubule, plays a role in urine glucose reabsorption. SGLT2 inhibitors (SGLT2i), have shown potential benefits beyond cardiac and renal improvement in preventing and treating cognitive impairment (CI), including mild cognitive impairment, Alzheimer's disease and vascular dementia in T2DM patients. Studies suggest that SGLT2i may ameliorate diabetic CI through metabolism pathways, inflammation, oxidative stress, neurotrophic factors and AChE inhibition. Clinical trials and meta-analyses have reported significant and insignificant results. Given their vascular effects, SGLT2i may offer unique protection against vascular CI. This review compiles mechanisms and clinical evidence, emphasizing the need for future analysis, evaluation, trials and meta-analyses to verify and recommend optimal SGLT2i selection and dosage for specific patients.

Research advances on CaMKs-mediated neurodevelopmental injury

Calcium/calmodulin-dependent protein kinases (CaMKs) are important proteins in the calcium signaling cascade response pathway, which can broadly regulate biological functions in vivo. Multifunctional CaMKs play key roles in neural development, including neuronal circuit building, synaptic plasticity establishment, and neurotrophic factor secretion. Currently, four familial proteins, calcium/calmodulin-dependent protein kinase I (CaMKI), calcium/calmodulin-dependent protein kinase II (CaMKII), eukaryotic elongation factor 2 kinase (eEF2K, popularly known as CaMKIII) and calcium/calmodulin-dependent protein kinase IV (CaMKIV), are thought to have been the most extensively studied during neurodevelopment. Although their spatial structures are extremely similar, as well as the initial starting point of activation, both require the activation of calcium and calmodulin (CaM) complexes to be involved in the process, and the phosphorylation sites and modes of each member are different. Furthermore, due to the high structural similarity of CaMKs, their members may play synergistic roles in the regulation of neural development, but different CaMKs also have their own means of regulating neural development. In this review, we first describe the visualized protein structural forms of CaMKI, CaMKII, eEF2K and CaMKIV, and then describe the functions of each kinase in neurodevelopment. After that, we focus on four main mechanisms of neurodevelopmental damage caused by CaMKs: CaMKI/ERK/CREB pathway inhibition leading to dendritic spine structural damage; Ca2+/CaM/CaMKII through induction of mitochondrial kinetic disorders leading to neurodevelopmental damage; CaMKIII/eEF2 hyperphosphorylation affects the establishment of synaptic plasticity; and CaMKIV/JNK/NF-κB through induction of an inflammatory response leading to neurodevelopmental damage. In conclusion, we briefly discuss the pathophysiological significance of aberrant CaMK family expression in neurodevelopmental disorders, as well as the protective effects of conventional CaMKII and CaMKIII antagonists against neurodevelopmental injury.

Curcumin triggers the Wnt/β-catenin pathway and shields neurons from injury caused by intermittent hypoxia

The objective of this study was to explore the molecular basis through which Curcumin (Cur) mitigates neuronal damage caused by obstructive sleep apnea (OSA). HT22 was used to simulate intermittent hypoxia (IH) injury and explore the effect of Cur on these cells. We evaluated the cell viability, cytotoxicity, apoptosis, proliferation, and Wnt/β-catenin (WβC) pathway. IWR-1 was used to block the pathway and investigate the protective mechanism of Cur. We constructed an in vivo model of IH to validate the results of the cellular experiments. IH accelerated apoptosis and cytotoxicity, suppressed proliferation, and decreased the activity of the WβC pathway. Cur can significantly improve cell viability, reduce apoptosis rate and cell toxicity, promote cell proliferation, and up-regulate the WβC. After blocking the WβC pathway, the proliferative effect of Cur was observably weakened. In vivo, IH caused hippocampal damage and inhibited WβC pathway activity in mice, which was ameliorated by Cur treatment. This implies that Cur could be a novel treatment option for neurological impairment brought on by OSA.

SGLT2 inhibitors: a novel therapy for cognitive impairment via multifaceted effects on the nervous system

The rising prevalence of diabetes mellitus has casted a spotlight on one of its significant sequelae: cognitive impairment. Sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally developed for diabetes management, are increasingly studied for their cognitive benefits. These benefits may include reduction of oxidative stress and neuroinflammation, decrease of amyloid burdens, enhancement of neuronal plasticity, and improved cerebral glucose utilization. The multifaceted effects and the relatively favorable side-effect profile of SGLT2 inhibitors render them a promising therapeutic candidate for cognitive disorders. Nonetheless, the application of SGLT2 inhibitors for cognitive impairment is not without its limitations, necessitating more comprehensive research to fully determine their therapeutic potential for cognitive treatment. In this review, we discuss the role of SGLT2 in neural function, elucidate the diabetes-cognition nexus, and synthesize current knowledge on the cognitive effects of SGLT2 inhibitors based on animal studies and clinical evidence. Research gaps are proposed to spur further investigation.

Insights on effects of Wnt pathway modulation on insulin signaling and glucose homeostasis for the treatment of type 2 diabetes mellitus: Wnt activation or Wnt inhibition?

Type 2 diabetes mellitus (T2DM) is a major worldwide chronic disease and can lead to serious diabetic complications. Despite the availability of many anti-diabetic agents in the market, they are unable to meet the long-term treatment goals. Also, they cause many side effects which justify the need for novel class of anti-diabetic drugs with newer mechanism of action. Wnt signaling is one of such novel target pathways which can be explored for metabolic disorders. Many key components of the Wnt signaling are involved in the regulation of glucose homeostasis. Polymorphism in the Transcription factor 7-like 2 (TCF7L2) gene, and mutations in the LRP5 (LDL Receptor Related Protein 5) gene lead to disturbed glucose metabolism and obesity. Despite of several years of research in this field, there is no concrete proof of concept available on whether Wnt activation or Wnt inhibition is the beneficial approach for the treatment of T2DM. Here, we have summarized the conclusions of relevant published research studies to give structured insights into possibilities to explore Wnt modulation as a novel target pathway for the treatment of T2DM. The review also highlights the present challenges and future opportunities towards the development of anti-diabetic small molecules targeting the Wnt signaling pathway.

Dapagliflozin Presented Nonalcoholic Fatty Liver Through Metabolite Extraction and AMPK/NLRP3 Signaling Pathway

In recent years, the incidence rate of nonalcoholic fatty liver disease (NAFLD) has been increasing year by year. The experiments conducted on rat elucidated the effect and underlying mechanism of dapagliflozin in NAFLD. Sprague Dawley rats were fed with HFD (Fat accounts for 52%, carbohydrate 34% and protein 14%) for 12 weeks as NAFLD model. Dapagliflozin presented NAFLD in rat model. Dapagliflozin reduced oxidative stress and inflammation in rat model of NAFLD. Dapagliflozin reduced oxidative stress and inflammation in vitro model of NAFLD. Dapagliflozin in a model of NAFLD metabolized into histamine H1 receptor, caffeine metabolism, mannose type O-glycan biosynthesis, choline metabolism in cancer, tryptophan metabolism, and glycerophospholipid metabolism. Dapagliflozin induced AMPK/NLRP3 signaling pathway. The regulation of AMPK/NLRP3 signaling pathway affected the effects of dapagliflozin on nonalcoholic fatty liver. In summary, dapagliflozin plays a preventative role in NAFLD through metabolite extraction, the inhibition of oxidative stress, and inflammation by AMPK/NLRP3 signaling pathway. Dapagliflozin may be a potential therapeutic agent for oxidative stress and inflammation in model of NAFLD.

Insights into the lipophilicity of four commonly prescribed antidiabetic drugs and their simultaneous analysis using a simple TLC-spectrodensitometric method: Application to fixed-dose combination tablets and human plasma

The retention and lipophilicity characteristics of four oral antidiabetic drugs namely; Metformin (MET), Linagliptin (LIN), Empagliflozin (EMP), and Dapagliflozin (DAP) were evaluated by a facile TLC-spectrodensitometric method. The developed method was validated and employed for simultaneous determination of the investigated drugs in their synthetic quaternary mixture, single- and multi-component tablets, and human plasma. The separation of the cited drugs was achieved using silica gel G 60F₂₅₄-TLC plates and a mobile system consisting of n-butanol: water: glacial acetic acid (7: 3: 1, v/v/v). After scanning at 234 nm, good linearities (10.0-2000.0 ng/band for each drug) and correlation coefficients (r = 0.99882-0.99972) with lower limits of detection and quantitation (2.17-3.58 and 6.57-10.85 ng/band, respectively) were statistically calculated. The obtained recoveries (98.35-101.38%) proved the wide applicability of the established method for concurrent estimation of the studied antidiabetics in fixed-dose combination tablets and human plasma. Besides, the present work was extended to estimate the lipophilicity parameters of the targeted drugs. Molecular lipophilicity (R_M), relative lipophilicity (R_M0), and lipophilic descriptor (C₀) were calculated for MET, LIN, EMP, and DAP. Good correlations (r = 0.8729-0.9933) between the chromatographic retention data and molecular descriptors of the studied drugs were attained. The obtained results confirmed the poor lipophilicity of MET and LIN compared to EMP and DAP. Lastly, understanding the lipophilicity of the cited drugs may be promising for the future design of safer and more effective formulations for diabetes mellitus, cancer, and Alzheimer's disease. Over and above, this work may be further applied to QSAR studies.