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.