Increase of circulating miR-223 and insulin-like growth factor-1 is associated with the pathogenesis of acute ischemic stroke in patients

Abstract

Background: The relationship between circulating microRNA-223 and pathogenesis of acute ischemic stroke is unknown. Here we investigated the roles and possible targets of circulating microRNA-223 in human ischemic stroke within the first 72 hours.

Methods: Blood samples were collected from patients within 72 hours after cerebral ischemia (n = 79) and compared with healthy control samples (n = 75). The level of possible downstream factors of microRNA-223 including insulin-like growth factor-1, insulin-like growth factor-1 receptor and interleukin-6 was examined by ELISA assay. The relationship between the microRNA-223 level and NIHSS scores, TOAST subtypes, and infarct volume was analyzed respectively. In addition, twelve adult male CD-1 mice underwent middle cerebral artery occlusion using the suture technique. Circulating blood and brain tissue in the ischemic ipsilateral hemisphere were collected at 24 hours after middle cerebral artery occlusion. microRNA-223 was detected by real-time polymerase chain reactions.

Results: microRNA-223 levels in the circulating blood of acute ischemic stroke patients were greatly increased compared to the control (p < 0.05). microRNA-223, which were negatively correlated with NIHSS scores (r = -0.531, p < 0.01) and infarct volume (r = -0.265, p = 0.039), was significantly up-regulated in large artery and small artery strokes. The plasma level of insulin-like growth factor-1 was positively associated with that of microRNA-223 (r = 0.205, p = 0.022). Moreover, microRNA-223 in blood and brain were positively correlated (r = 0.834, p < 0.05), and they were up-regulated significantly in mice that underwent middle cerebral artery occlusion (p < 0.05).

Conclusions: Our results suggest that microRNA-223 is associated with acute ischemic stroke and possibly plays a role in stroke through up-regulating growth factor such as insulin-like growth factor-1 gene.

Figure 1

Blood miR-223 levels were significantly increased in acute ischemic stroke. Box plots showed the expression of blood miR-223 in patients and control. The Y axis indicated miR-223 expression levels by log2 change. *, p < 0.05, stroke patients vs. control. Data are median (25% percentile, 75% percentile), n = 79 in stroke group, n = 75 in control group.

Figure 2

The time course of miR-223 expression and the correlation analysis between miR-223 and clinical information. A. miR-223 was highly expressed in 1 day and 3 days stroke patients. Box plots exhibited the time course of miR-223 expression in stroke patients. *, p < 0.05, 1 day vs. control; **, p < 0.01, 3 days vs. control. n = 75 in control group, n = 15 in 1 day group, n = 22 in 2 days group, n = 42 in 3 days group. B. miR-223 was significantly up-regulated in patients with LA and SA strokes. Box plots exhibited the miR-223 expression level among different subtypes. *, p < 0.05, LA vs. control; **, p < 0.01, SA vs. control. n = 75 in control, n = 37 in LA, n = 5 in CE, n = 9 in SA, n = 28 in UN. Data are median (25% percentile, 75% percentile). The Y axis showed the miR-223 expression levels by log2 change. C. The scatterplot showed miR-223 levels were negatively associated with NIHSS scores. r = −0.531, p < 0.01. D. The scatterplot showed miR-223 levels have a negative correlation with infarct volume of stroke patients. r = −0.265, p = 0.039.

Figure 3

Blood and brain miR-223 levels were elevated and they have a positive correlation in mice. A. Bar graphs showed the expression of miR-223 in brain tissue and blood of MCAO mice at 1 day. *, p < 0.05; **, p < 0.01, MCAO vs. sham. Data are mean ± SD, n = 6 in each group. B. The scatter plot demonstrated the positive correlation between blood miR-223 and brain miR-223 at 1 day after ischemia. r = 0.834, p < 0.05, n = 6.

Figure 4

The relationship between miR-223 and IGF1R, IGF-1 and IL-6. A. Line chart exhibited the changes of miR-223, IGF-1, IGF1R and IL-6 within 72 hours. Data are median, n = 75 in control, n = 15 in 1 day group, n = 22 in 2 days group, n = 42 in 3 days group. B. The scatterplot showed miR-223 was not associated with IGF1R after ischemia. r = −0.023, p = 0.795. C. The scatterplot demonstrated miR-223 was positively correlated to IGF-1. r = 0.205, p = 0.022. D. The scatterplot showed miR-223 was not associated with IL-6 after ischemia. r = −0.058, p = 0.522.