CKD is associated with recurrent ischemia but not with hemorrhagic transformation in acute ischemic stroke patients

Uremic Toxic Blood-Brain Barrier Disruption Mediated by AhR Activation Leads to Cognitive Impairment during Experimental Renal Dysfunction

BACKGROUND

Uremic toxicity may play a role in the elevated risk of developing cognitive impairment found among patients with CKD. Some uremic toxins, like indoxyl sulfate, are agonists of the transcription factor aryl hydrocarbon receptor (AhR), which is widely expressed in the central nervous system and which we previously identified as the receptor of indoxyl sulfate in endothelial cells.

METHODS

To characterize involvement of uremic toxins in cerebral and neurobehavioral abnormalities in three rat models of CKD, we induced CKD in rats by an adenine-rich diet or by 5/6 nephrectomy; we also used AhR^-/- knockout mice overloaded with indoxyl sulfate in drinking water. We assessed neurologic deficits by neurobehavioral tests and blood-brain barrier disruption by SPECT/CT imaging after injection of ^99mTc-DTPA, an imaging marker of blood-brain barrier permeability.

RESULTS

In CKD rats, we found cognitive impairment in the novel object recognition test, the object location task, and social memory tests and an increase of blood-brain barrier permeability associated with renal dysfunction. We found a significant correlation between ^99mTc-DTPA content in brain and both the discrimination index in the novel object recognition test and indoxyl sulfate concentrations in serum. When we added indoxyl sulfate to the drinking water of rats fed an adenine-rich diet, we found an increase in indoxyl sulfate concentrations in serum associated with a stronger impairment in cognition and a higher permeability of the blood-brain barrier. In addition, non-CKD AhR^-/- knockout mice were protected against indoxyl sulfate-induced blood-brain barrier disruption and cognitive impairment.

CONCLUSIONS

AhR activation by indoxyl sulfate, a uremic toxin, leads to blood-brain barrier disruption associated with cognitive impairment in animal models of CKD.

An analysis of the risk of perioperative ischemic stroke in patients undergoing non-cardiovascular and non-neurological surgeries

Objectives: This study aimed to assess the preoperative risk factor for perioperative ischemic stroke (PIS) in patients undergoing non-cardiovascular and non-neurological surgeries.Methods: Patients were retrospectively enrolled and grouped into two groups at a ratio of 1:2 according to their PIS status, i.e. patients with PIS in disease group, and patients without PIS in control group. Univariate analysis and multivariate logistic regression analysis were performed on admission laboratory test indices and preoperative risk factors for stroke. The pooled cohort equation (PCE), Essen Stroke Risk Score (ESRS), and Stroke Prognostic Instrument II (SPI-II) were used to separately assess the risk of stroke in patients with or without a history of stroke.Results: There were significant differences between the two groups in the levels of high-density lipoprotein cholesterol (HDL-C), prealbumin, renal insufficiency, dyslipidemia, coronary heart disease, anemia, and hemoglobin; the incidence of electrolyte disturbance; and previous histories of smoking, drinking, and stroke. Multivariate logistic regression analysis showed that renal insufficiency, histories of smoking and stroke, and decreased HDL-C can increase the risk of PIS. There were no significant differences between the disease group and the control group in ESRS or SPI-II score in patients with stroke history. There was a significant difference between the two groups in the risk of PIS evaluated by PCE in patients without stroke history.Conclusions: History of stroke and smoking, renal insufficiency, and low HDL-C are independent risk factors for PIS. It is feasible to assess the risk of stroke in preoperative patients using PCE in clinical practice.

Glomerular Filtration Rate is Associated with Hemorrhagic Transformation in Acute Ischemic Stroke Patients without Thrombolytic Therapy

Background:

Whether there is a relationship between glomerular filtration rate (GFR) and hemorrhagic transformation (HT) after acute ischemic stroke (AIS) is still under debate. The aim of our study was to determine whether the GFR level is a predictor of HT in AIS patients without thrombolytic therapy (TT).

Methods:

Consecutive AIS patients without TT were included in this prospective study from January 2014 to December 2016 in the First Affiliated Hospital of Chongqing Medical University. We divided them into two groups (HT and non-HT group) and meticulously collected baseline characteristics and laboratory and imaging data of interested individuals. Multivariate regression analysis was performed to assess the correlation between GFR and HT in stroke patients without TT.

Results:

Among 426 consecutive patients, 74 (17.3%) presented HT (mean age: 65 ± 12 years, number of male patients: 47) on the follow-up scans. In multivariate regression analysis, HT was significantly associated with low GFR (odds ratio [OR] = 3.708, confidence interval [CI] = 1.326–10.693, P = 0.013), atrial fibrillation (AF; OR = 2.444, CI = 1.087–5.356, P = 0.027), large cerebral infarction (OR = 2.583, CI = 1.236–5.262, P = 0.010), and hypoalbuminemia (HA; OR = 4.814, CI = 1.054–22.153, P = 0.037) for AIS patients without TT.

Conclusions:

The present study strongly showed that lower GFR is an independently predictor of HT; in addition, large infarct volume, AF, and HA are also important risks of HT for AIS patients without TT, which offered a practical information that risk factors should be paid attention or eliminated to prevent HT for stroke patients though the level of evidence seems to be unstable.

Serum magnesium but not calcium was associated with hemorrhagic transformation in stroke overall and stroke subtypes: a case-control study in China

Association between serum calcium and magnesium versus hemorrhagic transformation (HT) remains to be identified. A total of 1212 non-thrombolysis patients with serum calcium and magnesium collected within 24 h from stroke onset were enrolled. Backward stepwise multivariate logistic regression analysis was conducted to investigate association between calcium and magnesium versus HT. Calcium and magnesium were entered into logistic regression analysis in two models, separately: model 1, as continuous variable (per 1-mmol/L increase), and model 2, as four-categorized variable (being collapsed into quartiles). HT occurred in 140 patients (11.6%). Serum calcium was slightly lower in patients with HT than in patient without HT (P = 0.273). But serum magnesium was significantly lower in patients with HT than in patients without HT (P = 0.007). In logistic regression analysis, calcium displayed no association with HT. Magnesium, as either continuous or four-categorized variable, was independently and inversely associated with HT in stroke overall and stroke of large-artery atherosclerosis (LAA). The results demonstrated that serum calcium had no association with HT in patients without thrombolysis after acute ischemic stroke. Serum magnesium in low level was independently associated with increasing HT in stroke overall and particularly in stroke of LAA.

Chronic Kidney Disease and Carotid Atherosclerosis in Patients With Acute Stroke

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) is increasingly recognized as an independent risk factor for cardiovascular disease and stroke. Our aim was to examine the association between estimated glomerular filtration rate (eGFR) and carotid plaques, stenosis and occlusions, and to assess whether CKD and its severity affect carotid atherosclerosis in a cohort of unselected patients with acute stroke.

METHODS

A total of 249 consecutive patients with acute stroke (ischemic or hemorrhagic) were included in this study and baseline eGFR, carotid intima-media thickness (cIMT), and carotid stenosis were evaluated. The eGFR was calculated using the modified Modification of Diet in Renal Disease equation, which was adjusted for data from Chinese CKD patients. An eGFR rate of <60 mL/min/1.73 m was defined as CKD. The cIMT and carotid plaques were detected by carotid ultrasound.

RESULTS

CKD, defined as eGFR<60 mL/min/1.73 m, was found in 66 individuals (26.50%). Among the 5 subtypes, the level of low-density lipoprotein cholesterol was significantly higher in the moderate and severe stenosis groups compared with the normal, elevated cIMT and mild stenosis groups (P<0.01). The value of eGFR gradually decreased with increasing degree of carotid stenosis, and the differences between the groups were statistically significant (P<0.01). On linear regression analysis, eGFR was negatively correlated with the degree of carotid stenosis (r=0.03; P<0.05). On ordinal logistic regression analysis, eGFR was an independent risk factor associated with carotid atherosclerosis (1.05; 95% confidence interval, 0.47-1.63).

CONCLUSIONS

There was a significant burden of atherosclerosis among individuals with CKD. CKD is an independent predictor of carotid plaques, stenoses, and occlusions in patients with acute stroke.

Lower serum calcium level is associated with hemorrhagic transformation after thrombolysis

BACKGROUND AND PURPOSE

We aim to investigate whether lower admission serum calcium levels are associated with hemorrhagic transformation (HT) after intravenous thrombolysis (IVT).

METHODS

A total of 362 patients treated with IVT was divided into 4 quartiles based on admission serum calcium levels (Q1[<2.16], Q2[2.16, 2.23], Q3[2.24, 2.31], and Q4[>2.31] mmol/L). HT was classified as hemorrhagic infarction and parenchymal hemorrhage. Logistic regression was applied to assess the association between serum calcium levels and the incidence of HT.

RESULTS

Compared with Q4, HT was more common in Q1 (odds ratio, 2.580; 95% CI, [1.258-5.292]; P=0.010), Q2 (odds ratio, 2.382; 95% CI, [1.163-4.877]; P=0.018), and Q3 (odds ratio, 2.293; 95% CI, [1.133-4.637]; P=0.021). Hemorrhagic infarction was more common in Q1 (P=0.037), and Q2 (P=0.018), compared with Q4, and parenchymal hemorrhage was more common in Q1 (P=0.029) than Q4.

CONCLUSIONS

Lower admission serum calcium level is independently associated with HT after IVT, and this hypothesis needs larger confirmatory trials.