Is There Enhanced Risk of Cerebral Ischemic Stroke by Sulfonylureas in Type 2 Diabetes?

Pure Isolated Internuclear Ophthalmoplegia as Presentation of Midbrain Ischemic Stroke: A Case Report

Internuclear ophthalmoplegia (INO) is a condition characterized by impaired ocular movement, leading to an inability to perform coordinated lateral gaze, resulting in ophthalmoplegia. This impairment results from damage to the medial longitudinal fasciculus (MLF), which can occur because of various types of lesions localized in the pons or midbrain. In this case, we report on a 67-year-old man with multiple comorbidities who arrived at the emergency department with complaints of sudden dizziness and an unsteady gait. During the examination, he exhibited left INO, which was characterized by limited left eye adduction and multidirectional nystagmus of the right eye when performing right lateral gaze.

Regulatory effects associated with changes in intracellular potassium level in susceptibility to mitochondrial depolarization and excitotoxicity

Excitotoxicity has been believed to be one of the causes of neurodegenerative diseases such as Alzheimer's disease and Huntington's disease. So far, much research has been done to suppress the neuronal excessive excitations, however, we still have not achieved full control, which may be due to the lack of some factors. As a matter of course, there is an urgent need to clarify all mechanisms that inhibit the onset and progression of neurodegenerative diseases. We found that potassium ion level regulation may be important in the sense that it suppresses mitochondrial depolarization rather than hyperpolarization of cell membrane potential. Minoxidil, an opener of ATP-activated potassium (K_ATP) channels decreased injury with middle cerebral artery occlusion in vivo experiment using TTC staining. In the primary cortical neurons, N-methyl-D-aspartate (NMDA)-induced mitochondrial depolarization was suppressed by minoxidil treatment. Minoxidil inhibited the increase in levels of cleaved caspase 3 and the release of cytochrome c into the cytosol, further reducing potassium ion levels. It was observed decreased potassium levels in neurons by the treatment of minoxidil. Those effects of minoxidil were blocked by glibenclamide. Therefore, it was suggested that minoxidil, via opening of K_ATP channels, reduced intracellular potassium ion level that contribute to mitochondrial depolarization, and suppressed subsequent NMDA-induced mitochondrial depolarization. Our findings suggest that the control of ion levels in neurons could dominate the onset and progression of neurodegenerative diseases.

Elevated blood glucose is associated with aggravated brain edema in acute stroke

BACKGROUND AND PURPOSE

Clinical outcome after endovascular thrombectomy in patients with acute ischemic stroke still varies significantly. Higher blood glucose levels (BGL) have been associated with worse clinical outcome, but the pathophysiological causes are not yet understood. We hypothesized that higher levels of BGL are associated with more pronounced ischemic brain edema and worse clinical outcome mediated by cerebral collateral circulation.

METHODS

178 acute ischemic stroke patients who underwent mechanical thrombectomy were included. Early ischemic brain edema was determined using quantitative lesion water uptake on initial computed tomography (CT) and collateral status was assessed with an established 5-point scoring system in CT-angiography. Good clinical outcome was defined as functional independence (modified Rankin Scale [mRS] score 0-2). Multivariable logistic regression analysis was performed to predict functional independence and linear regression analyses to investigate the impact of BGL and collateral status on water uptake.

RESULTS

The mean BGL at admission was significantly lower in patients with good outcome at 90 days (116.5 versus 138.5 mg/dl; p < 0.001) and early water uptake was lower (6.3% versus 9.6%; p < 0.001). The likelihood for good outcome declined with increasing BGL (odds ratio [OR] per 100 mg/dl BGL increase: 0.15; 95% CI 0.02-0.86; p = 0.039). Worse collaterals (1% water uptake per point, 95% CI 0.4-1.7%) and higher BGL (0.6% per 10 mg/dl BGL, 95% CI 0.3-0.8%) were significantly associated with increased water uptake.

CONCLUSION

Elevated admission BGL were associated with increased early brain edema and poor clinical outcome mediated by collateral status. Patients with higher BGL might be targeted by adjuvant anti-edematous treatment.

Association of Antihyperglycemic Therapy with Risk of Atrial Fibrillation and Stroke in Diabetic Patients

Type 2 diabetes mellitus (DM) is associated with an increased risk of cardiovascular disease (CVD). Atrial fibrillation (AF) and stroke are both forms of CVD that have major consequences in terms of disabilities and death among patients with diabetes; however, they are less present in the preoccupations of scientific researchers as a primary endpoint of clinical trials. Several publications have found DM to be associated with a higher risk for both AF and stroke; some of the main drugs used for glycemic control have been found to carry either increased, or decreased risks for AF or for stroke in DM patients. Given the risk for thromboembolic cerebrovascular events seen in AF patients, the question arises as to whether stroke and AF occurring with modified incidences in diabetic individuals under therapy with various classes of antihyperglycemic medications are interrelated and should be considered as a whole. At present, the medical literature lacks studies specifically designed to investigate a cause-effect relationship between the incidences of AF and stroke driven by different antidiabetic agents. In default of such proof, we reviewed the existing evidence correlating the major classes of glucose-controlling drugs with their associated risks for AF and stroke; however, supplementary proof is needed to explore a hypothetically causal relationship between these two, both of which display peculiar features in the setting of specific drug therapies for glycemic control.

Antidiabetic drugs and stroke risk. Current evidence

Cardiovascular disease (CVD) is the major cause of morbidity and mortality for individuals with type 2 diabetes (T2D). In particular, the risk for stroke is twice that of patients without diabetes, and diabetes may be responsible for >8% of first ischemic strokes. Therefore, the way to prevent stroke in these patients has become an important issue. Traditionally, glucose-lowering drugs had not been shown to protect against stroke. Moreover, several antidiabetic drugs (i.e., sulfonylureas, rosiglitazone) have been reported to be associated with increased risks of CVD and stroke. On the contrary, data on the CV risks and benefits associated with new antidiabetic treatment in patients with T2D are emerging - and look promising. Therefore, it could be of great value to find out if any type of these new antidiabetic agents has protective effect against stroke. We review the available evidence regarding the risk of stroke in individuals taking non-insulin antidiabetic agents. To date, several antidiabetic agents have shown to have a positive effect on stroke prevention. The accumulated evidence suggests that metformin, pioglitazone and semaglutide reduce stroke risk. These agents do not represent only a way of controlling blood glucose and but also offer the opportunity to reduce stroke risk. Surely, new data from ongoing and future studies will provide additional information to select the best treatment for decreasing stroke risk in T2D patients.

Isolated INO as a presentation of midbrain paramedian area lacunar infarction in patients with diabetes

The clinical features and pathogenesis of the pure midbrain infarction need to be described. Of 4257 stroke patients who were on the stroke registry between January 2000 and December 2015, 25 patients with pure midbrain infarctions, as demonstrated on diffusion-weighted magnetic resonance imaging, were enrolled. We analyzed the clinical features, MRI findings, and etiologic mechanisms of the infarctions. According to the distribution of each penetrating artery of the midbrain, we classified all the infarctions into paramedian (PM) area (13 patients), lateral area (10 patients), and PM and lateral areas (2 patients). In the lacunar infarction of the PM area group (8 patients), 6 patients had diabetes mellitus (DM), and 5 patients showed isolated anterior internuclear ophthalmoplegia (INO)-the ratio was much higher than that of the non-PM-lacunar infarction group. Patients with DM were more likely to develop lacunar infarction of the midbrain PM area than that of non-diabetics. Data suggest that isolated INO is a presentation of midbrain PM area lacunar infarction in patients with DM.