Clinical study on the changes of platelet microparticles in inflammatory bowel disease / 中华消化杂志

ABSTRACT

Objective:To investigate the relationship between the expression level of platelet microparticle (PMP) and the disease activity of inflammatory bowel disease (IBD) in IBD patients, and to explore the ability of PMP from different sources to induce the formation of neutrophil extracellular trap (NET) in vitro. Methods:From May 2018 to July 2019, 118 patients with IBD admitted to the Department of Gastroenterology at The First Affiliated Hospital of Anhui Medical University were selected, among whom 54 cases were ulcerative colitis (UC) patients (UC group) and mild, moderate and severe cases were 17, 25 and 12, respectively; and 64 cases were Crohn′s disease (CD) (CD group), 6 were in remission stage, and mild, moderate, severe cases were 27, 22 and 9, respectively. During the same period, 35 healthy individuals with normal checkups were selected as the healthy control group. Specimens were collected and the expression levels of PMP were measured by flow cytometry.And the correlation between the expression level of PMP and the disease activity index (DAI) score was analyzed.NET formation experiment groups were set up, including neutrophils of healthy control group (6 cases), neutrophils of IBD group (6 cases), neutrophils of healthy controls + PMP of IBD group (12 cases) and neutrophils of healthy controls+ PMP group (6 cases). After immunofluorescence staining, the proportion of NET formation of each group was observed under laser scanning confocal microscopy (LSCM). Mann-Whitney U test, Spearman correlation analysis and Independent-sample t test were used for statistical analysis. Results:The expression levels of PMP in peripheral blood of the UC group and the CD group were 2 184.5(2 817.0)/μL and 2 209.0(2 409.0)/μL, respectively, which were all higher than that of the healthy control group (776.0(407.0)/μL), and the differences were statistically significant ( U=-6.018 and -6.426, both P<0.01). The expression level of PMP of patients with severe UC was 3 873.0(4 611.3)/μL, which was higher than those of patients with mild or moderate UC (1 248.0(1 888.0)/μL and 1 432.0(1 783.0)/μL, respectively), and the differences were statistically significant ( U=-2.745 and -2.547, both P<0.05). The expression level of PMP of patients with severe CD was 5 658.0(5 067.5)/μL, which was higher than those of patients with mild or moderate CD or in remission (1 327.5(1 934.0)/μL, 1 405.0(2 965.0)/μL and 2 300.0(1 552.0)/μL, respectively), and the differences were statistically significant ( U=-1.650, -1.955 and -1.306, all P<0.05). There was no statistically significant difference in the expression level of PMP between the UC group and the CD group, between the mild and moderate UC patients, and between the CD in remission and the mild, moderate patients (all P>0.05). The results of correlation analysis showed that the expression levels of PMP in peripheral blood of patients with UC or CD were positively correlated with DAI score and CRP ( r=0.406, 0.358, 0.325, and 0.256; all P<0.05). The proportion of NET formation in the neutrophils of healthy control+ PMP of IBD group was (14.67±5.35) %, which was higher than those of the neutrophils of healthy control groap, neutrophils of IBD group and neutrophils of healthy control+ PMP group ((2.00±0.63)%, (1.67±0.82)% and (5.83±2.86)%), and the differences were statistically significant ( t=5.694, 8.230 and 3.748, all P<0.05). There was no statistically significant difference in the proportion of NET formation between the neutrophils of healthy control group and the neutrophils of IBD group ( P>0.05). Conclusions:The expression level of PMP in peripheral blood of IBD patients increases and is correlated with the disease activity degree in IBD patients. PMP has the ability to induce the NET formation in neutrophils. Moreover, PMP of IBD patients is more likely to induce NET formation than those of healthy individuals, which may be involved in the intestinal inflammatory process by activating neutrophils to produce NET.