Cytokine network in acute stroke

Temporal dynamics of peripheral neutrophil and lymphocytes following acute ischemic stroke

BACKGROUND

The immune response to acute ischemic stroke (AIS) is implicated in diagnosis, prognosis, and intervention; however, the temporal dynamics of leukocytes following AIS are poorly understood. The purpose of this study was to characterize peripheral leukocyte dynamics following AIS among individuals with poor and favorable outcomes.

METHODS

A retrospective chart review was conducted among patients with a diagnosis of AIS who were treated at a comprehensive stroke center across a 3-year timeframe. Groups were defined according to stroke outcomes. Patients with poor outcomes were distinguished from those with favorable outcomes by discharge National Institute of Health Stroke Score, infarct size, and Modified Rankin Scale. Leukocyte counts were compared among controls and AIS outcome groups.

RESULTS

The neutrophil-lymphocyte ratio (NLR) calculated at 48-72 h post-AIS was identified as the strongest predictor of outcome. NLR was significantly higher in the poor outcome group (8.68 ± 0.93) compared with both the favorable outcome (4.5 ± 0.51, p = 0.009) and control group (4.33 ± 0.66, p < 0.001). Patients with a 48-72 h NLR ≥ 4.58 were 5.58 times more likely to have a poor outcome than AIS patients with an NLR < 4.58.

CONCLUSIONS

The results of this study improve the understanding of the immune response in AIS. Low neutrophil count relative to high lymphocyte count at 48-72 h post-AIS should be considered a predictor of a favorable stroke outcome. Conversely, high neutrophil count relative to low lymphocyte count at 48-72 h post-AIS should be considered a predictor of a poor stroke outcome.

Cytokine changes in the pathophysiology of poststroke depression

OBJECTIVE

Poststroke depression (PSD) is a frequent psychiatric sequela after stroke, and its influence is detrimental. However, the etiology of PSD is still not clear. Although many studies have indicated that immune dysregulation plays an important role in the pathophysiology of depression, it is still unknown if PSD involves the same mechanism. Thus, the current study objectives were to evaluate whether there were cytokine changes when patients with ischemic stroke suffered from PSD.

METHOD

We included ischemic stroke patients without depression when the stroke occurred and followed them for 1 year. The Hamilton Depression Rating Scale score and cytokines were assessed at baseline and at the 1st, 3rd, 6th, 9th and 12th months after stroke.

RESULTS

One hundred four patients with ischemic stroke participated and completed the study, and 12 suffered from PSD during the 1-year study period. There were significant increases in the cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor α (TNF-α) and interferon-γ, and the ratios of IL-6/IL-10 and TNF-α/IL-10 were also elevated. Interleukin-1β was too low to show any difference.

CONCLUSION

Our study suggested that immune imbalance plays a possible role in the pathophysiology of PSD and that IL-6 and TNF-α are key cytokines.