Brain White Matter Fiber Bundle Alterations and Severity of Depression in Patients with Post-stroke Depression
Post-stroke depression (PSD) , a common complication in stroke patients, may increase the disability and mortality, however, its pathogenesis is unknown yet.
To observe the white matter fiber bundle alterations by diffusion tensor tractography (DTT) , and to explore its correlation with depression in patients with PSD.
Participants were selected from the First Affiliated Hospital of Jinzhou Medical University from September 2019 to September 2020, involving 40 inpatients with first-episode ischemic stroke (20 were found with PSD, and 20 without) , and 20 physical examinees as healthy controls. DTT was performed in all participants, fractional anisotropy (FA) and number of fiber bundles in regions of interest (ROIs) were compared across PSD and non-PSD inpatients and healthy controls. Pearson correlation analysis was performed to analyze the correlations of FA and number of fiber bundles on the side of stroke in the ROIs with 24-item Hamilton Rating Scale for Depression (HAMD-24) in PDS inpatients.
In PSD inpatients, the FA of inferior fronto-occipital fascicles, corticospinal tract, frontopontine tract, cingulum bundle and uncinate fasciculus on the side of the stroke was significantly lower than those on the contralateral side (P<0.05) . And the number of fiber bundle of inferior fronto-occipital fascicles, corticospinal tract and frontopontine tract on the side of the stroke was significantly less than those on the contralateral side (P<0.05) . Compared to non-PSD inpatients or healthy controls, PSD inpatients demonstrated significantly lower FA of inferior fronto-occipital fascicles, corticospinal tract, frontopontine tract, cingulum bundle and uncinate fasciculus, and notable less number of fiber bundles of inferior fronto-occipital fascicles, corticospinal tract and frontopontine tract on the side of the stroke (P<0.05) . Pearson correlation analysis revealed that, the FA of inferior fronto-occipital fascicles, corticospinal tract, frontopontine tract, cingulum bundle or uncinate fasciculus on the side of the stroke was negatively correlated with HAMD-24 score in PSD inpatients (r=-0.469, -0.769, -0.728, -0.801, -0.839, P<0.05) ; the number of fiber bundle of inferior fronto-occipital fascicles, corticospinal tract or frontopontine tract on the side of the stroke was negatively correlated with HAMD-24 score in PSD inpatients (r=-0.858, -0.806, -0.694, P<0.01) .
There were impairment changes of structure of inferior fronto-occipital fascicles, corticospinal tract, frontopontine tract, cingulum bundle and uncinate fasciculus in patients with PSD, and these changes may be significantly correlated with the severity of depression, indicating that some white matter fiber bundle alterations may be involved in the onset of PSD.
Correlation Study between Serum Trimethylamine-N-oxide and the Risk of Acute Ischemic Stroke
Assessment of the risks of stroke and then initiation of primary prevention are crucial to reducing the incidence rate of stroke. Trimethylamine-N-oxide (TMAO) is a recently discovered intestinal microbial metabolite, whose relationships with the risks of stroke have been rarely reported.
To explore the correlation between serum TMAO levels and the risks of acute ischemic stroke (AIS) .
With the supporting by the project of the National Health Commission (stroke high risk population screening and intervention) , five hundred cases were randomly selected from the stroke screening population in the New Urban Community of Hohhot city of Inner Mongolia from October to December 2020. Finally, 399 cases were included according to the set of standard, and then the 399 cases were divided into normal control group (n=121) , moderate AIS risk group (n=141) , and high AIS risk group (n=137) in accordance with the screening results (score of stroke risk rated using a scoring card) . Demographic and laboratory indices (including serum TMAO detected using ELISA) of all cases were collected. Pearson correlation test and Spearman rank correlation test were conducted to measure the correlation of TMAO with AIS risks. Multinomial and ordinal Logistic regressions were used to explore the influencing factors of AIS risks. ROC analysis was used to estimate the predictive value of TMAO for AIS risk.
Compared with the control group, the serum TMAO level in high-risk group was increased significantly (P<0.05) . Correlation analysis results found that serum TMAO level was negatively associated with increased age, being female, history of hypertension, diabetes history, current smoking and drinking consumption (r=-0.182, rs=-0.130, -0.262, -0.147, -0.178, -0.140, P<0.05) , but positively associated with lack of exercise and increased BMI (rs=0.153, r=0.210, P<0.05) .The multinomial and ordinal Logistic regression analyses showed that increased TMAO was independently associated with increased risk of AIS (B=3.084, SE=0.426, P<0.001) . The AUC of serum TMAO in predicting AIS risk was 0.790 〔95%CI (0.737, 0.837) 〕with 62.0% sensitivity and 91.6% specificity when its optimal cut-off value was determined as 3.28 μmol/L.
Serum TMAO level may be independently related to AIS, which could be used as a clinical predictor for AIS.
The Glymphatic System：a New Exploration of Pathological Mechanism in Stroke
The glymphatic system is a system that promotes the exchange and flow of cerebrospinal fluid (CSF) -interstitial fluid (ISF) to maintain the balance of CSF-ISF, and rid the neuropil of toxic proteinaceous metabolites with astroglial water channel aquaporin-4 as the mediator. Increasing evidence has shown that the glymphatic system is strongly related to the pathological changes and outcomes of stroke. Available studies have found that the glymphatic system partially affects post-stroke cerebrospinal fluid circulation and cerebral edema. Different types of strokes include acute ischemic stroke, subarachnoid hemorrhage and intracerebral hemorrhage also have pathological changes in the glymphatic system. This review summarizes the structure and function of the glymphatic system, and the latest developments in its impact on pathological changes of different types of strokes, providing a new direction for the prevention and treatment of stroke.
