Decreased Insulin Sensitivity and Impaired Fibrinolytic Activity in Type 2 Diabetes Patients and Nondiabetics with Ischemic Stroke

Prognostic significance of the stress hyperglycemia ratio and admission blood glucose in diabetic and nondiabetic patients with spontaneous intracerebral hemorrhage

BACKGROUND

The role of stress hyperglycemia ratio (SHR) on the prognosis of spontaneous intracerebral hemorrhage (ICH) in patients with different diabetic status has not been elucidated. This study aimed to evaluate the prognostic value of SHR and admission blood glucose (ABG) for the short- and long-term mortality in diabetic and nondiabetic populations with ICH.

METHOD

Participants with ICH were retrospectively retrieved from the Medical Information Mart for Intensive Care (MIMIC-IV). The primary outcome was all-cause 30-day and 1-year mortality. The association of SHR and ABG with the primary outcomes in diabetic and nondiabetic cohorts were assessed by Cox proportional hazard regression.

RESULTS

Overall, 1029 patients with a median age of 71.09 (IQR: 60.05-81.97) were included. Among them, 548 (53%) individuals were male, and 95 (19%) as well as 323 (31%) ones experienced the 30-day and 1-year mortality, respectively. After adjusting for confounding variables, individuals in quintile 5 of SHR had significantly higher risk of the 30-day and 1-year mortality than those in quintile 1 in the whole cohort (30-day mortality: HR 3.33, 95%CI 2.01-5.51; 1-year mortality: HR 2.09, 95% CI 1.46-3.00) and in nondiabetic patients (30-day mortality: HR 4.55, 95%CI 2.33-8.88; 1-year mortality: HR 3.06, 95%CI 1.93-4.86), but no significant difference was observed in diabetic patients. Similar results were observed for ABG as a categorical variable. As continuous variable, SHR was independently correlated with the 30-day and 1-year mortality in both of the diabetic and nondiabetic cohorts (30-day mortality: HR 2.63, 95%CI 1.50-4.60. 1-year mortality: HR 2.12, 95%CI 1.33-3.39), but this correlation was only observed in nondiabetic cohort for ABG (HR 1.00, 95%CI 0.99-1.01 for both of the 30-day and 1-year mortality). Moreover, compared with ABG, SHR can better improve the C-statistics of the original models regarding the 30-day and 1-year outcomes, especially in patients with diabetes (p < 0.001 in all models).

CONCLUSION

SHR might be a more useful and reliable marker than ABG for prognostic prediction and risk stratification in critically ill patients with ICH, especially in those with diabetes.

Neuroprotective Panel of Olive Polyphenols: Mechanisms of Action, Anti-Demyelination, and Anti-Stroke Properties

Neurological diseases such as stroke and multiple sclerosis are associated with high morbidity and mortality, long-term disability, and social and economic burden. Therefore, they represent a major challenge for medical treatment. Numerous evidences support the beneficial effects of polyphenols from olive trees, which can alleviate or even prevent demyelination, neurodegeneration, cerebrovascular diseases, and stroke. Polyphenols from olive oils, especially extra virgin olive oil, olive leaves, olive leaf extract, and from other olive tree derivatives, alleviate inflammation and oxidative stress, two major factors in demyelination. In addition, they reduce the risk of stroke due to their multiple anti-stroke effects, such as anti-atherosclerotic, antihypertensive, antioxidant, anti-inflammatory, hypocholesterolemic, hypoglycemic, and anti-thrombotic effects. In addition, olive polyphenols have beneficial effects on the plasma lipid profiles and insulin sensitivity in obese individuals. This review provides an updated version of the beneficial properties and mechanisms of action of olive polyphenols against demyelination in the prevention/mitigation of multiple sclerosis, the most common non-traumatic neurological cause of impairment in younger adults, and against cerebral insult with increasing incidence, that has already reached epidemic proportions.

Crosstalk between neurological, cardiovascular, and lifestyle disorders: insulin and lipoproteins in the lead role

Insulin resistance and impaired lipoprotein metabolism contribute to a plethora of metabolic and cardiovascular disorders. These alterations have been extensively linked with poor lifestyle choices, such as consumption of a high-fat diet, smoking, stress, and a redundant lifestyle. Moreover, these are also known to increase the co-morbidity of diseases like Type 2 diabetes mellitus and atherosclerosis. Under normal physiological conditions, insulin and lipoproteins exert a neuroprotective role in the central nervous system. However, the tripping of balance between the periphery and center may alter the normal functioning of the brain and lead to neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke, depression, and multiple sclerosis. These neurological disorders are further characterized by certain behavioral and molecular changes that show consistent overlap with alteration in insulin and lipoprotein signaling pathways. Therefore, targeting these two mechanisms not only reveals a way to manage the co-morbidities associated with the circle of the metabolic, central nervous system, and cardiovascular disorders but also exclusively work as a disease-modifying therapy for neurological disorders. In this review, we summarize the role of insulin resistance and lipoproteins in the progression of various neurological conditions and discuss the therapeutic options currently in the clinical pipeline targeting these two mechanisms; in addition, challenges faced in designing these therapeutic approaches have also been touched upon briefly.

Triglyceride Glucose Index and Prognosis of Patients With Ischemic Stroke

Background: The triglyceride glucose index (TyG index) has been proposed as a simple and credible surrogate marker of insulin resistance. However, it is unclear whether TyG index correlates with adverse clinical outcomes in patients with ischemic stroke. Accordingly, this study aimed to explore the relationship between baseline TyG index and clinical outcomes of ischemic stroke individuals. Methods: We included eligible subjects with ischemic stroke from the China National Stroke Registry II for the current analysis. TyG index was calculated and divided into quartiles to explore the relationship with the outcomes of ischemic stroke. Outcomes included stroke recurrence, all-cause mortality, poor functional outcome at 12 months, and neurologic worsening at discharge. Multivariable Cox regression and logistic regression models were performed to explore the correlation of baseline TyG index with the outcomes. Results: Among the 16,310 patients enrolled in the study, the average age was 64.83 ± 11.9 years, and 63.48% were men. The median TyG index was 8.73 (interquartile range, 8.33-9.21). After adjustment for multiple potential covariates, the fourth quartile of TyG index was associated with an increased risk of stroke recurrence (adjusted HR, 1.32; 95% CI, 1.11-1.57; P = 0.002), all-cause mortality (adjusted HR, 1.25; 95%CI, 1.06-1.47; P = 0.01) at 12-month follow-up, and neurological worsening (adjusted OR, 1.26; 95% CI, 1.02-1.55; P = 0.03) at discharge, but not poor functional outcome compared with the first quartile. Conclusion: TyG index representing insulin resistance was associated with an increased risk of stroke recurrence, all-cause mortality, and neurologic worsening in patients with ischemic stroke.

Vascular Damage in Obesity and Diabetes: Highlighting Links Between Endothelial Dysfunction and Metabolic Disease in Zebrafish and Man

Endothelial dysfunction is an initial pathophysiological mechanism of vascular damage and is further recognized as an independent predictor of negative prognosis in diabetes-induced micro- and macrovascular complications. Insight into the capability of zebrafish to model metabolic disease like obesity and type II diabetes has increased and new evidence on the induction of vascular pathologies in zebrafish through metabolic disease is available. Here, we raise the question, if zebrafish can be utilized to study the initial impairments of vascular complications in metabolic disorders. In this review, we focus on the advances made to develop models of obesity and type II diabetes in zebrafish, discuss the key points and characteristics of these models, while highlighting the available information linked to the development of endothelial dysfunction in zebrafish and man. We show that larval and adult zebrafish develop metabolic dysregulation in the settings of obesity and diabetes, exhibiting pathophysiological mechanisms, which mimic the human condition. The most important genes related to endothelial dysfunction are present in zebrafish and further display similar functions as in mammals. Several suggested contributors to endothelial dysfunction found in these models, namely hyperinsulinaemia, hyperglycaemia, hyperlipidaemia and hyperleptinaemia are highlighted and the available data from zebrafish are summarised. Many underlying processes of endothelial dysfunction in obesity and diabetes are fundamentally present in zebrafish and provide ground for the assumption, that zebrafish can develop endothelial dysfunction. Conservation of basic biological mechanisms is established for zebrafish, but focused investigation on the subject is now needed as validation and particularly more research is necessary to understand the differences between zebrafish and man. The available data demonstrate the relevance of zebrafish as a model for metabolic disease and their ability to become a proponent for the investigation of vascular damage in the settings of obesity and diabetes.

mTOR Inhibitor Therapy and Metabolic Consequences: Where Do We Stand?

mTOR (mechanistic target of rapamycin) protein kinase acts as a central integrator of nutrient signaling pathways. Besides the immunosuppressive role after solid organ transplantations or in the treatment of some cancers, another promising role of mTOR inhibitor as an antiaging therapeutic has emerged in the recent years. Acute or intermittent rapamycin treatment has some resemblance to calorie restriction in metabolic effects such as an increased insulin sensitivity. However, the chronic inhibition of mTOR by macrolide rapamycin or other rapalogs has been associated with glucose intolerance and insulin resistance and may even provoke type II diabetes. These metabolic adverse effects limit the use of mTOR inhibitors. Metformin is a widely used drug for the treatment of type 2 diabetes which activates AMP-activated protein kinase (AMPK), acting as calorie restriction mimetic. In addition to the glucose-lowering effect resulting from the decreased hepatic glucose production and increased glucose utilization, metformin induces fatty acid oxidations. Here, we review the recent advances in our understanding of the metabolic consequences regarding glucose metabolism induced by mTOR inhibitors and compare them to the metabolic profile provoked by metformin use. We further suggest metformin use concurrent with rapalogs in order to pharmacologically address the impaired glucose metabolism and prevent the development of new-onset diabetes mellitus after solid organ transplantations induced by the chronic rapalog treatment.

Insulin resistance in ischemic stroke

Insulin resistance often refers to a pathological condition in which cells fail to respond to the normal actions of insulin. Increasing literature has noted a critical role of insulin resistance in the pathogenesis of ischemic stroke. Insulin resistance plays an important role in the pathogenesis of ischemic stroke via enhancing advanced changes of atherosclerosis. A variety of literature indicates that insulin resistance enhances platelet adhesion, activation and aggregation which are conducive to the occurrence of ischemic stroke. Insulin resistance also induces hemodynamic disturbances and contributes to the onset of ischemic stroke. In addition, insulin resistance may augment the role of the modifiable risk factors in ischemic stroke and induce the occurrence of ischemic stroke. Preclinical and clinical studies have supported that improving insulin resistance may be an effective measure to prevent or delay ischemic stroke.

N-acetylcysteine attenuates systemic platelet activation and cerebral vessel thrombosis in diabetes

Objective

We previously demonstrated that diabetes exacerbates stroke-induced brain injury, and that this correlates with brain methylglyoxal (MG)-to-glutathione (GSH) status. Cerebral injury was reversed by N-acetylcysteine (NAC). Here we tested if the pro-thrombotic phenotype seen in the systemic circulation and brain during diabetes was associated with increased MG-glycation of proteins, and if NAC could reverse this.

Methods

The streptozotocin (STZ)-induced mouse model of type 1 diabetes was used. Thrombus formation in venules and arterioles (pial circulation) was determined by intravital videomicroscopy using the light-dye method. Circulating blood platelet-leukocyte aggregates (PLAs) were analyzed by flow cytometry 1 wk before other measurements. GSH and MG levels in platelets were measured by HPLC. MG-modified proteins, glutathione peroxidase-1 (GPx-1), and superoxide dismutase-1 (SOD1) levels were detected in platelets by western blot at 20 weeks. Proteins involved in coagulation were quantified by ELISA. NAC (2 mM) was given in drinking water for 3 weeks before the terminal experiment.

Results

Thrombus development was accelerated by diabetes in a time-dependent manner. % PLAs were significantly elevated by diabetes. Plasma activated plasminogen activator inhibitor type 1 levels were progressively increased with diabetes duration, with tail bleeding time reduced by 20 wks diabetes. Diabetes lowered platelet GSH levels, GPx-1 and SOD-1 expression. This was associated with higher MG levels, and increased MG-adduct formation in platelets. NAC treatment partly or completely reversed the effects of diabetes.

Conclusion

Collectively, these results show that the diabetic blood and brain become progressively more susceptible to platelet activation and thrombosis. NAC, given after the establishment of diabetes, may offer protection against the risk for stroke by altering both systemic and vascular prothrombotic responses via enhancing platelet GSH, and GSH-dependent MG elimination, as well as correcting levels of antioxidants such as SOD1 and GPx-1.

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Diabetes elevates dicarbonyl stress leading to enhanced thrombosis in the brain.

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Glutathione levels decrease leading to impaired elimination of methylglyoxal in platelets during diabetes.

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Platelet proteins are glycated and platelets form aggregates with leukocytes in diabetes.

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Diabetes increases circulating levels of plasminogen activator inhibitor-1.

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NAC, via GSH synthesis, reverses the platelet activation, protein glycation and pro-coagulation responses & protects against thrombosis in the diabetic brain.

Prognostic Value of Admission Blood Glucose in Diabetic and Non-diabetic Patients with Intracerebral Hemorrhage

We aimed to validate prognostic value of elevated admission blood glucose (ABG) for clinical outcomes in diabetic and non-diabetic patients with intracerebral hemorrhage (ICH) in a representative large cohort. Data of ICH patients with onset time ≤24 h were derived from the China National Stroke Registry. Clinical outcomes included 3-month poor outcome (death or dependency) and death. Logistic regression was performed for the association between ABG and clinical outcomes, both in the entire cohort and in patients with and without diabetes mellitus. 2951 ICH patients were enrolled, including 267 (9.0%) diabetics. In the entire cohort, there was a trend to increased risk of poor outcome with increasing ABG levels (adjusted OR 1.09; 95% CI, 1.04–1.15; P < 0.001). The risk of poor outcome was significantly greatest for the highest quartile (≥7.53 mmol/L) of ABG (adjusted OR 1.54; 95% CI, 1.17–2.03; p = 0.002, P for trend 0.004). We got similar association in non-diabetics but not in diabetics. Elevated ABG confers a higher risk of poor outcome in non-diabetics than diabetics with similar glucose level. Elevated ABG is an independent predictor of 3-month poor outcome in ICH patients, the prognostic value of which is greater in non-diabetics than diabetics with similar glucose level.