High glucose-induced effects on Na+-K+-2Cl- cotransport and Na+/H+ exchange of blood-brain barrier endothelial cells: involvement of SGK1, PKCβII, and SPAK/OSR1

The association in diabetic retinopathy and stroke finding from NHANES evidence

PURPOSE

Diabetic retinopathy and stroke are both vascular pathologies, and this study intends to investigate the relationship between diabetic retinopathy and stroke.

METHODS

The NHANES database was used to find the relationship between diabetic retinopathy and stroke with 1948 individuals aged 40 years or older. The sensitivity of the data was verified by multiple interpolation, further analysis was done by subgroup analyses, and possible links were investigated with mediation studies.

RESULTS

Diabetes retinopathy was found to be closely associated with stroke, with the PDR group having a higher stroke incidence than the NPDR group. After controlling for covariates, there were still substantial differences in the risk of stroke among patients with NPDR and PDR. Overall, subgroup analysis revealed DR group showed an important distinction, compared to the non-DR (OR = 1.76, 95% CI 1.15-2.64). The results of the mediation research indicated that the connection between DR and stroke was mediated by the frailty index and hypertension.

CONCLUSION

This study demonstrated a statistically significant correlation between DR and stroke, which persisted even after DR staging and was more prevalent in PDR patients than in NPDR patients. Stroke prevention may benefit from DR health management.

SPAK inhibitor ZT-1a attenuates reactive astrogliosis and oligodendrocyte degeneration in a mouse model of vascular dementia

BACKGROUND

Astrogliosis and white matter lesions (WML) are key characteristics of vascular contributions to cognitive impairment and dementia (VCID). However, the molecular mechanisms underlying VCID remain poorly understood. Stimulation of Na-K-Cl cotransport 1 (NKCC1) and its upstream kinases WNK (with no lysine) and SPAK (the STE20/SPS1-related proline/alanine-rich kinase) play a role in astrocytic intracellular Na+ overload, hypertrophy, and swelling. Therefore, in this study, we assessed the effect of SPAK inhibitor ZT-1a on pathogenesis and cognitive function in a mouse model of VCID induced by bilateral carotid artery stenosis (BCAS).

METHODS

Following sham or BCAS surgery, mice were randomly assigned to receive either vehicle (DMSO) or SPAK inhibitor ZT-1a treatment regimen (days 14-35 post-surgery). Mice were then evaluated for cognitive functions by Morris water maze, WML by ex vivo MRI-DTI analysis, and astrogliosis/demyelination by immunofluorescence and immunoblotting.

RESULTS

Compared to sham control mice, BCAS-Veh mice exhibited chronic cerebral hypoperfusion and memory impairments, accompanied by significant MRI DTI-detected WML and oligodendrocyte (OL) death. Increased activation of WNK-SPAK-NKCC1-signaling proteins was detected in white matter tissues and in C3d+ GFAP+ cytotoxic astrocytes but not in S100A10+ GFAP+ homeostatic astrocytes in BCAS-Veh mice. In contrast, ZT-1a-treated BCAS mice displayed reduced expression and phosphorylation of NKCC1, decreased astrogliosis, OL death, and WML, along with improved memory functions.

CONCLUSION

BCAS-induced upregulation of WNK-SPAK-NKCC1 signaling contributes to white matter-reactive astrogliosis, OL death, and memory impairment. Pharmacological inhibition of the SPAK activity has therapeutic potential for alleviating pathogenesis and memory impairment in VCID.

Machine learning predictors of risk of death within 7 days in patients with non-traumatic subarachnoid hemorrhage in the intensive care unit: A multicenter retrospective study

Non-traumatic subarachnoid hemorrhage (SAH) is a critical neurosurgical emergency with a high mortality rate, imposing a significant burden on both society and families. Accurate prediction of the risk of death within 7 days in SAH patients can provide valuable information for clinicians, enabling them to make better-informed medical decisions. In this study, we developed six machine learning models using the MIMIC III database and data collected at our institution. These models include Logistic Regression (LR), AdaBoosting (AB), Multilayer Perceptron (MLP), Bagging (BAG), Gradient Boosting Machines (GBM), and Extreme Gradient Boosting (XGB). The primary objective was to identify predictors of death within 7 days in SAH patients admitted to intensive care units. We employed univariate and multivariate logistic regression as well as Pearson correlation analysis to screen the clinical variables of the patients. The initially screened variables were then incorporated into the machine learning models, and the performance of these models was evaluated. Furthermore, we compared the performance differences among the six models and found that the MLP model exhibited the highest performance with an AUC of 0.913. In this study, we conducted risk factor analysis using Shapley values to identify the factors associated with death within 7 days in patients with SAH. The risk factors we identified include Gcsmotor, bicarbonate, wbc, spo2, heartrate, age, nely, glucose, aniongap, GCS, rbc, sysbp, sodium, and gcseys. To provide clinicians with a useful tool for assessing the risk of death within 7 days in SAH patients, we developed a web calculator based on the MLP machine learning model.

Function and therapeutic value of astrocytes in diabetic cognitive impairment

Diabetic cognitive impairment (DCI) is a complex complication of diabetes in the central nervous system, and its pathological mechanism is still being explored. Astrocytes are abundant glial cells in central nervous system that perform diverse functions in health and disease. Accumulating excellent research has identified astrocyte dysfunction in many neurodegenerative diseases (such as Alzheimer's disease, aging and Parkinson's disease), and summarized and discussed its pathological mechanisms and potential therapeutic value. However, the contribution of astrocytes to DCI has been largely overlooked. In this review, we first systematically summarized the effects and mechanisms of diabetes on brain astrocytes, and found that the diabetic environment (such as hyperglycemia, advanced glycation end products and cerebral insulin resistance) mediated brain reactive astrogliosis, which was specifically reflected in the changes of cell morphology and the remodeling of signature molecules. Secondly, we emphasized the contribution and potential targets of reactive astrogliosis to DCI, and found that reactive astrogliosis-induced increased blood-brain barrier permeability, glymphatic system dysfunction, neuroinflammation, abnormal cell communication and cholesterol metabolism dysregulation worsened cognitive function. In addition, we summarized effective strategies for treating DCI by targeting astrocytes. Finally, we discuss the application of new techniques in astrocytes, including single-cell transcriptome, in situ sequencing, and prospected new functions, new subsets and new targets of astrocytes in DCI.

Influence of Optimal Management of Hyperglycemia and Intensive Nursing on Blood Glucose Control Level and Complications in Patients with Postoperative Cerebral Hemorrhage

Background

Cerebral hemorrhage, also known as hemorrhagic stroke, is a common clinical cerebrovascular disease, accounting for about 10%-30% of stroke, with high morbidity and mortality.

Objective

To observe the effect of optimal management of hyperglycemia and intensive nursing on blood glucose control level and complications in patients with postoperative cerebral hemorrhage.

Methods

One hundred and eight patients with postoperative cerebral hemorrhage comorbid with stress hyperglycemia admitted to our neurosurgery department from February 2019 to February 2022 were selected and divided into a general group of 54 cases and an optimized group of 54 cases by simple random method. The general group was managed with conventional care, while the optimized group developed optimized management of hyperglycemia for intensive care. The indexes related to blood glucose control, electrolytes, National Institutes of Health Stroke Scale (NIHSS) scores, Barthel Index (BI) scores, and time to achieve blood glucose standard, insulin pumping time, patient satisfaction, and prognosis were compared between the two groups.

Results

Before intervention, there was no statistical significance in the comparison of blood glucose control-related indicators and electrolytes between the two groups (P > 0.05). After 7 d and 14 d of intervention, the fasting blood glucose and 2 h postprandial blood glucose in the two groups were lower than before, while K+ and Na+ were higher than before (P < 0.05). The blood glucose indexes at the same time point in the optimized group were found to be lower than those in the general group by statistical analysis, but electrolytes were not statistically significant when compared with the general group (P > 0.05). In the optimized group, the time to achieve blood glucose standard (6.59 ± 1.94) d and insulin pumping time (7.14 ± 1.89) d were shorter than those in the general group [(7.48 ± 2.12) d and (8.58 ± 2.14) d], insulin dosage (748.85 ± 63.61) U was less than that in the general group (923.54 ± 84.14) U, and the incidence of hypoglycemia (3.70%) was lower than that in the general group (16.67%), and the satisfaction rate (92.59%) was higher than that of the general group (77.78%), which was statistically significant (P < 0.05). Before intervention, there was no significant difference in NIHSS score and BI score between the two groups (P > 0.05). After 7 d and 14 d of intervention, the NIHSS scores of the two groups were lower than before, while the BI scores were higher than before, and the NIHSS scores of the optimized group at the same time point were all lower than those of the general group, and the BI scores were higher than those of the general group (P < 0.05). The incidence of pulmonary infection (11.11%) and rebleeding (7.41%) in the optimized group were lower than those in the general group (25.93% and 22.22%), while deep vein thrombosis, multiple organ dysfunction syndrome (MODS), and death within 28 d was not statistically significant when compared with the general group (P > 0.05).

Conclusion

Optimal management of hyperglycemia and intensive nursing can effectively control the blood sugar level of patients after cerebral hemorrhage, reducing insulin dosage, and the occurrence of hypoglycemia, pulmonary infection, and rebleeding.

Amelioration of endothelial dysfunction by sodium glucose co-transporter 2 inhibitors: pieces of the puzzle explaining their cardiovascular protection

Sodium glucose co‐transporter 2 inhibitors (SGLT‐2is) improve cardiovascular outcomes in both diabetic and non‐diabetic patients. Preclinical studies suggest that SGLT‐2is directly affect endothelial function in a glucose‐independent manner. The effects of SGLT‐2is include decreased oxidative stress and inflammatory reactions in endothelial cells. Furthermore, SGLT2is restore endothelium‐related vasodilation and regulate angiogenesis. The favourable cardiovascular effects of SGLT‐2is could be mediated via a number of pathways: (1) inhibition of the overactive sodium‐hydrogen exchanger; (2) decreased expression of nicotinamide adenine dinucleotide phosphate oxidases; (3) alleviation of mitochondrial injury; (4) suppression of inflammation‐related signalling pathways (e.g., by affecting NF‐κB); (5) modulation of glycolysis; and (6) recovery of impaired NO bioavailability. This review focuses on the most recent progress and existing gaps in preclinical investigations concerning the direct effects of SGLT‐2is on endothelial dysfunction and the mechanisms underlying such effects.

Mechanistic insights into the role of serum-glucocorticoid kinase 1 in diabetic nephropathy: A systematic review

Aberrant expression of serum-glucocorticoid kinase 1 (SGK1) contributes to the pathogenesis of multiple disorders, including diabetes, hypertension, obesity, fibrosis, and metabolic syndrome. SGK1 variant is expressed in the presence of insulin and several growth factors, eventually modulating various ion channels, carrier proteins, and transcription factors. SGK1 also regulates the enzymatic activity of Na⁺ K⁺ ATPase, glycogen synthase kinase-3, ubiquitin ligase Nedd4-2, and phosphomannose mutase impacting cell cycle regulation, neuroexcitation, and apoptosis. Ample evidence supports the crucial role of aberrant SGK1 expression in hyperglycemia-mediated secondary organ damage. Diabetic nephropathy (DN), a dreadful microvascular complication of diabetes, is the leading cause of end-stage renal failures with high morbidity and mortality rate. The complex pathogenesis of DN encompasses several influencing factors, including transcriptional factors, inflammatory markers, cytokines, epigenetic modulators, and abnormal enzymatic activities. SGK1 plays a pivotal role by controlling various physiological functions associated with the occurrence and progression of DN; therefore, targeting SGK1 may favorably influence the clinical outcome in patients with DN. This review aimed to provide mechanistic insights into SGK1 regulated DN pathogenesis and summarize the evidence supporting the therapeutic potential of SGK1 inhibition and its consequences on human health.

Pharmacological tools to target NKCC1 in brain disorders

The chloride importer NKCC1 and the chloride exporter KCC2 are key regulators of neuronal chloride concentration. A defective NKCC1/KCC2 expression ratio is associated with several brain disorders. Preclinical/clinical studies have shown that NKCC1 inhibition by the United States FDA-approved diuretic bumetanide is a potential therapeutic strategy in preclinical/clinical studies of multiple neurological conditions. However, bumetanide has poor brain penetration and causes unwanted diuresis by inhibiting NKCC2 in the kidney. To overcome these issues, a growing number of studies have reported more brain-penetrating and/or selective bumetanide prodrugs, analogs, and new molecular entities. Here, we review the evidence for NKCC1 pharmacological inhibition as an effective strategy to manage neurological disorders. We also discuss the advantages and limitations of bumetanide repurposing and the benefits and risks of new NKCC1 inhibitors as therapeutic agents for brain disorders.

Metabolic Disturbances Induced by Sleep Restriction as Potential Triggers for Alzheimer's Disease

Sleep has a major role in learning, memory consolidation, and metabolic function. Although it is known that sleep restriction increases the accumulation of amyloid β peptide (Aβ) and the risk to develop Alzheimer's disease (AD), the mechanism behind these effects remains unknown. In this review, we discuss how chronic sleep restriction induces metabolic and cognitive impairments that could result in the development of AD in late life. Here, we integrate evidence regarding mechanisms whereby metabolic signaling becomes disturbed after short or chronic sleep restriction in the context of cognitive impairment, particularly in the accumulation of Aβ in the brain. We also discuss the role of the blood-brain barrier in sleep restriction with an emphasis on the transport of metabolic signals into the brain and Aβ clearance. This review presents the unexplored possibility that the alteration of peripheral metabolic signals induced by sleep restriction, especially insulin resistance, is responsible for cognitive deficit and, subsequently, implicated in AD development.

Inhibition of the p‑SPAK/p‑NKCC1 signaling pathway protects the blood‑brain barrier and reduces neuronal apoptosis in a rat model of surgical brain injury

Surgical brain injury (SBI) can disrupt the function of the blood‑brain barrier (BBB), leading to brain edema and neurological dysfunction. Thus, protecting the BBB and mitigating cerebral edema are key factors in improving the neurological function and prognosis of patients with SBI. The inhibition of WNK lysine deficient protein kinase/STE20/SPS1‑related proline/alanine‑rich kinase (SPAK) signaling ameliorates cerebral edema, and this signaling pathway regulates the phosphorylation of the downstream Na⁺‑K⁺‑Cl^‑ cotransporter 1 (NKCC1). Therefore, the purpose of the present study was to investigate the role of SPAK in SBI‑induced cerebral edema and to determine whether the SPAK/NKCC1 signaling pathway was involved in SBI via regulating phosphorylation. An SBI model was established in male Sprague‑Dawley rats, and the effects of SPAK on the regulation of the NKCC1 signaling pathway on BBB permeability and nerve cell apoptosis by western blotting analysis, immunofluorescence staining, TUNEL staining, Fluoro‑Jade C staining, and brain edema and nervous system scores. The results demonstrated that, compared with those in the sham group, phosphorylated (p)‑SPAK and p‑NKCC1 protein expression levels were significantly increased in the SBI model group. After inhibiting p‑SPAK, the expression level of p‑NKCC1, neuronal apoptosis and BBB permeability were significantly reduced in SBI model rats. Taken together, these findings suggested that SBI‑induced increases in p‑SPAK and p‑NKCC1 expression exacerbated post‑traumatic neural and BBB damage, which may be mediated via the ion‑transport‑induced regulation of cell edema.