Atherosclerosis,inflammatory factor changes,cognitive disorder and vascular endothelial functions in patients with different grades of leukoaraiosis

Abstract

OBJECTIVE:

To study the atherosclerosis (AS), inflammatory factor level, cognitive disorder and vascular endothelial functions in patients with different grades of leukoaraiosis (LA), and to explore the correlations of different grades of LA with cognitive disorder.

METHODS:

A total of 180 patients with cerebral infarction admitted and treated in the Department of Neurology of our hospital were selected, and they were graded according to the Tarvonen-shcolder standard, with 45 patients in each group. The atherosclerotic plaques of the patients were detected via a color Doppler ultrasound system and magnetic resonance imaging (MRI). Their inflammatory factor levels were determined using enzyme-linked immunosorbent assay (ELISA). The cognitive function was scored based on the mini-mental state examination (MMSE), and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), endothelin (ET) and nitric oxide (NO) were measured to evaluate vascular endothelial functions.

RESULTS:

According to the comparisons among four groups of the patients, the incidence rate of AS was gradually increased among patients with different grades of LA (p < 0.05). With the aggravation of LA, the levels of inflammatory factors in patients were obviously increased (p < 0.05). LA patients had evidently lowered MMSE scores and levels of SOD and NO, but notably raised inflammatory factors C-reactive protein (CRP) and matrix metalloproteinase-9 (MMP-9) and vascular endothelial function indices MDA and ET (p < 0.05).

CONCLUSION:

The occurrence of LA is implicated with the increasing levels of inflammatory factors in the patients, aggregation of cognitive dysfunction and impairment vascular endothelial functions.

Keywords

Leukoaraiosis atherosclerosis inflammatory factors cognitive function vascular endothelial functions

1 Introduction

Leukoaraiosis (LA) is a disease with the manifestations of demyelination and gliosis of cerebral white matter, which is mostly caused by cerebrovascular diseases [1], and the majority of LA patients are elderly people. At the early stage, LA may exhibit no obvious clinical symptoms, while at the late stage, it will cause mental disorder, memory disorder, motor dysfunction and cognitive disorder and even cerebral cortical atrophy to patients, thus leading to progressive dementia and affecting the life quality of the patients [2,3, 2,3]. This study aims to explore the cognitive dysfunction, serum inflammatory factor level, atherosclerosis (AS) and vascular endothelial function change in patients with different grades of LA through collecting and analyzing their clinical data and also investigate the relationships of these factors with different grades of LA, thereby further elucidating the pathogenesis and influencing factors of LA and advancing the subsequent treatment for the patients. The specific study results are reported as follows.

2 Materials and methods

2.1 Basic information

A total of 180 patients with cerebral infarction admitted and treated in the Department of Neurology of our hospital from 2015 to 2018 were enrolled, and all patients were diagnosed with cerebral infarction through magnetic resonance imaging (MRI) or CT examinations. Among them, there were 81 females with the mean age of (58.4±4.8) years old and the disease course of 1–9 months, and 99 males with the mean age of (50.2±4.5) years old and the disease course of 1.5–12 months. According to the Tarvonen-shcolder standard [4], the degree of LA in patients was scored, and divided into four groups: the total score of 0 represented no LA (LA-0 group, n = 45), that less than 3 points mild LA (LA-1 group, n = 45), that less than 6 points moderate LA (LA-2 group, n = 45) and that no less than 6 points severe LA (LA-3 group, n = 45). This study excluded the patients suffering from senile dementia, Alzheimer’s disease, Parkinson’s syndrome, paralysis, aphasia or deafness, and all the included patients and their family members were informed of this study and consented. The study protocol was approved by the Research Ethics Committee of Inner Mongolia Baotou Steel Hospital (IMBSH-2014-1205).

2.2 Detection indicators

In the early morning of the second day after admission, blood was drawn from all fasting patients and centrifuged for the supernatant. Then the levels of serum inflammatory factors C-reactive protein (CRP), matrix metalloproteinase-9 (MMP-9), soluble CD40 ligand (sCD40L), complement 3 (C3) and C4 were determined via the enzyme-linked immunosorbent assay (ELISA) that was performed by specialized testers using the kit (CST) strictly according to the operation instructions of the kit. The patients were assessed by specialized research nurses for the Tarvonen-shcolder and mini-mental state examination (MMSE) scores, and all of them had clear awareness and could understand and answer all questions independently. Moreover, their carotid atherosclerotic plaques were detected using a color Doppler ultrasound system, and the levels of serum redox substances superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and endothelin (ET) were measured to assess the patients’ vascular endothelial functions.

2.3 Detection methods

The atherosclerotic plaque in patients was detected with a color Doppler ultrasound system, and when the vessels at 1-2 cm from carotid bifurcation exhibited the echo structure of intrusion into the lumen or carotid intima was thickened by about 1.3 mm, atherosclerotic plaque formation was defined. On the second day after admission, venous blood was taken from all the patients and then centrifuged, and the supernatant was obtained to measure the levels of serum CRP, MMP-9, C3, C4 and sCD40L via the ELISA. The cognitive function of the patients was assessed by the specialized research nurses using the MMSE scale [5] with the maximum of 50 points. The total score no less than 40 points indicated normal cognitive function, that no less than 30 points mild cognitive dysfunction, that no less than 20 points moderate cognitive dysfunction and that less than 20 points severe cognitive dysfunction. Finally, the vascular endothelial functions of the patients were evaluated based on the levels of SOD, NO, MDA and ET.

2.4 Statistical analysis

SPSS 17.0 was used for statistical analysis. Measurement data were expressed as ( $\bar{χ}$ ±s) and one-way analysis of variance was conducted for the comparisons of data among groups. Enumeration data were expressed as percentage and subjected to chi-square test. p < 0.05 suggested that the difference was statistically significant.

3 Results

3.1 Comparison of carotid AS among patients with different grades of LA

LA-0 group had 2 cases of unilateral carotid AS and no case of bilateral carotid AS. LA-1 group had 8 cases of unilateral carotid AS and 4 cases of bilateral carotid AS. In LA-2 group, there were 12 patients with unilateral carotid AS and 13 with bilateral carotid AS. LA-3 group exhibited 17 cases of unilateral carotid AS and 20 cases of bilateral carotid AS. Additionally, the incidence rates of arteriostenosis among these four groups of patients were 4.4%, 26.7%, 55.6% and 75.6%, respectively, and the differences were statistically significant among groups (p < 0.05) (Table 1).

Table 1
Comparison of carotid AS among patients with different grades of LA [n (%)]

AS location Degree of arteriostenosis [n (%)]

Unilateral Bilateral Mild Moderate Severe

LA-0 (n = 45) 2 2 (4.4)

2 0 1 1 0

LA-1 (n = 45) 12 12 (26.7)

8 4 6 4 2

LA-2 (n = 45) 25 25 (55.6)

12 13 14 7 4

LA-3 (n = 45) 37 34 (75.6)

17 20 11 12 14

	AS location	Degree of arteriostenosis [n (%)]
LA-0 (n = 45)	2		2 (4.4)
	2	0	1	1	0
LA-1 (n = 45)	12		12 (26.7)
	8	4	6	4	2
LA-2 (n = 45)	25		25 (55.6)
	12	13	14	7	4
LA-3 (n = 45)	37		34 (75.6)
	17	20	11	12	14

Note: ^*p < 0.05, vs. LA-0 group.

3.2 Comparison of inflammatory factor level among patients with different grades of LA

As LA was aggravated, the levels of serum CRP, MMP-9, C3 and C4 in patients were gradually increased, and there were statistically significant differences among the three groups: LA-1 group, LA-2 group and LA-3 group (p < 0.05), while the level of sCD40L was not obviously different among all groups of patients with different grades of LA, and there was no statistically significant difference (p < 0.05) (Table 2, Fig. 1A and B).

Table 2
Comparison of inflammatory factor level among patients with different grades of LA ( $\bar{χ}$ ±s)

Group sCD40L (ng/mL) C3 (g/L) C4 (g/L)

LA-0 (n = 45) 3.54±1.26 0.73±0.059 0.18±0.045

LA-1 (n = 45) 5.83±3.02 0.87±0.091 0.28±0.039

LA-2 (n = 45) 6.02±2.94 0.95±0.068 0.32±0.051

LA-3 (n = 45) 6.58±1.63 1.24±0.17 0.35±0.043

Group	sCD40L (ng/mL)	C3 (g/L)	C4 (g/L)
LA-0 (n = 45)	3.54±1.26	0.73±0.059	0.18±0.045
LA-1 (n = 45)	5.83±3.02	0.87±0.091	0.28±0.039
LA-2 (n = 45)	6.02±2.94	0.95±0.068	0.32±0.051
LA-3 (n = 45)	6.58±1.63	1.24±0.17	0.35±0.043

Fig.1A

and B. Comparisons of CRP and MMP-9 levels among patients with different grades of LA ( $\bar{χ}$ ±s). The levels of CRP and MMP-9 are increased to different extents in LA-1, 2 and 3 groups, and compared with LA-0 group, the differences are statistically significant (p < 0.05).

3.3 Comparison of MMSE score among patients with different grades of LA

Both LA degree score and cognitive dysfunction score (MMSE) were markedly different among all groups, showing statistical significance (p < 0.05). With the aggravation of LA in all groups of patients, the MMSE score was also gradually decreased, suggesting that LA affects the patients’ cognitive function (Table 3)

Table 3
Comparison of MMSE score among patients with different grades of LA ( $\bar{χ}$ ±s)

Group LA degree score MMSE score

LA-0 (n = 45) 0 47.4±6.53

LA-1 (n = 45) 2.1±0.8 37.5±8.41^*

LA-2 (n = 45) 4.7±1.2^* 21.8±5.42^*

LA-3 (n = 45) 8.1±1.7^* 14.4±6.36^*

Group	LA degree score	MMSE score
LA-0 (n = 45)	0	47.4±6.53
LA-1 (n = 45)	2.1±0.8	37.5±8.41^*
LA-2 (n = 45)	4.7±1.2^*	21.8±5.42^*
LA-3 (n = 45)	8.1±1.7^*	14.4±6.36^*

Note: ^*p < 0.05, vs. LA-0 group.

3.4 Comparisons of vascular endothelial factors among patients with different grades of LA

As the grade of LA was raised, the expression level of MDA in patients was increased with elevated activity, but the level of SOD was lowered, displaying statistically significant differences (p < 0.05). Meanwhile, with the vascular endothelial functions impaired, the NO synthesized and released by vascular endothelial cells was reduced, but the level of ET was raised (p < 0.05), suggesting that the higher the degree of LA in patients, the severer the endothelial function impairment (Table 4).

Table 4
Comparisons of vascular endothelial functions among patients with different grades of LA ( $\bar{χ}$ ±s)

Group MDA (mmol/mL) SOD (NU/mL) NO (μM/L) ET (pg/mL)

LA-0 (n = 45) 5.23±1.62 253.7±48.5 41.2±8.43 143.7±15.64

LA-1 (n = 45) 7.34±2.14 210.3±43.22 36.7±5.79 154.3±16.31

LA-2 (n = 45) 9.23±3.65 176.7±39.76 31.4±6.45 167.9±15.37

LA-3 (n = 45) 12.5±4.17 154.4±41.02 24.6±5.86 179.51±14.23

Group	MDA (mmol/mL)	SOD (NU/mL)	NO (μM/L)	ET (pg/mL)
LA-0 (n = 45)	5.23±1.62	253.7±48.5	41.2±8.43	143.7±15.64
LA-1 (n = 45)	7.34±2.14	210.3±43.22	36.7±5.79	154.3±16.31
LA-2 (n = 45)	9.23±3.65	176.7±39.76	31.4±6.45	167.9±15.37
LA-3 (n = 45)	12.5±4.17	154.4±41.02	24.6±5.86	179.51±14.23

Note: ^*p < 0.05, vs. LA-0 group.

3.5 Correlation analysis of different grades of LA with cognitive dysfunction score

The patients with a higher grade of LA had a lower cognitive dysfunction score, revealing that the LA degree score is negatively correlated with cognitive dysfunction score of the patients (r² = 0.8904, Fig. 2).

Fig.2

Correlation analysis of cognitive dysfunction for patients with different grades of LA. The higher the grade of LA, the lower the cognitive dysfunction score of the patients, revealing that LA degree score is negatively correlated with cognitive dysfunction score of the patients (r² = 0.8904).

4 Discussion

LA refers to the demyelination or degeneration of nerve conduction fibers, often accompanied with glial reactive hyperplasia [6, 7]. LA has the imaging feature of paraventricular low-density shadows with different areas and it, a highly-prevalent disease among middle-aged and elderly people, can be induced and exacerbated by hypertension, hyperglycemia, hyperlipidemia and AS. Its main clinical manifestations include cognitive dysfunction, mental disorder, affective disorder and reduced amount of exercise [8, 9]. Currently, it has been proven that LA is closely associated with cognitive dysfunction in patients [10]. LA patients can manifest apathy, depression and even senile dementia, greatly affecting the life quality of elderly people, so it is especially important to prevent and treat LA.

At present, there are multiple theories about the pathogenesis of LA, the most recognized of which is blood flow hypoperfusion injury, and blood-brain barrier damage and cerebral edema are also the important factors for worsened LA [11, 12]. Especially in elderly people with AS, carotid plaque formation can cause arteriostenosis to decrease cerebral perfusion, further giving rise to white matter demyelination, tissue looseness and edema and glial reactive hyperplasia [13]. Additionally, exfoliated atherosclerotic plaques can be transported into other small vessels along blood flow, thus resulting in their blockage and necrosis. Studies have demonstrated that cerebral hypoperfusion is the main pathogenesis of LA, but the relationships of the vascular sclerosis and plaque locations and affected site with the incidence of LA need to be further explored. In addition, serum inflammatory factors play important roles in the occurrence and development of LA, and they are even used as the biological indicators to assess LA [14, 15]. Bacterial infection and inflammation can induce the high expressions of serum inflammatory factors and other cytokines, and further destroy the blood-brain barrier through activating the complement pathway, thus aggravating LA. Now, there are more studies of MMP-9, sCD40L, C3, C4 and CRP. Besides, MMP-9 can also degrade extracellular matrices and exacerbate the blood-brain barrier destruction, leading to white matter damage [16], and it has been confirmed to be an important inflammatory factor for the occurrence and development of LA. Lastly, the change in vascular endothelial functions is also a key factor for LA. The decreased vitamin D absorption in elderly people reduces calcium concentration and vascular elasticity, making them vulnerable to vascular sclerosis and weakened functions [17, 18]. Furthermore, senile hyperlipidemia, hypertension and hyperglycemia can damage vascular endothelium, and the decreased reducing substances and increased oxidizing substances in vessels serve as critical factors for endothelial injuries [19].

The present study seeks to investigate the serum inflammatory factors, carotid AS and vascular endothelial function changes in patients with different grades of LA and analyze the correlation of different grades of LA with cognitive dysfunction. The results of this study showed that patients with different grades of LA had different carotid AS, inflammatory factor levels and vascular endothelial functions, and among them, those with a higher grade of LA exhibited a higher incidence rate of carotid AS and notably raised levels of serum inflammatory factors CRP, MMP-9, C3 and C4, with statistically significant differences (p < 0.05), but there was no obvious difference in the expression level of sCD40L among all groups of LA patients. The release of NO from vascular endothelial cells was reduced in LA patients with the rise of ET level, which is in line with previous study on the correlations of carotid intima-media thickness with endothelial function and atherosclerosis degree [20]. Notably, it has been shown that lacunar infarctions (LI) and deep white matter lesions (DWML) are epiphenomena may morphologically characterize cerebral microangiopathy but do not in themselves indicate cognitive impairment. Dementia or neuropsychological deficits, by contrast, are reflected exclusively by functional imaging parameters (rCBF, rMRGlu) and cerebral atrophy, suggesting that the cognition from simple imaging (CT and NMR) is insufficient, even if it is still practiced worldwide [21]. Our preliminary data thus explored the correlations of different grades of LA with cognitive dysfunction and we found that the higher the grade of LA, the lower the cognitive dysfunction score, and they were negatively correlated (r² = 0.8904). Taken together, our result demonstrate that LA is associated with the elevation of inflammation in the patients, severity of cognitive dysfunction and impairment vascular endothelial functions, which provides further assistance for the prevention and treatment of LA.

Conflict of interest

None.

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	AS location		Degree of arteriostenosis [n (%)]
	Unilateral	Bilateral	Mild	Moderate	Severe
LA-0 (n = 45)	2		2 (4.4)
	2	0	1	1	0
LA-1 (n = 45)	12		12 (26.7)
	8	4	6	4	2
LA-2 (n = 45)	25		25 (55.6)
	12	13	14	7	4
LA-3 (n = 45)	37		34 (75.6)
	17	20	11	12	14

Atherosclerosis,inflammatory factor changes,cognitive disorder and vascular endothelial functions in patients with different grades of leukoaraiosis

Abstract

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSION:

Keywords

1 Introduction

2 Materials and methods

2.1 Basic information

2.2 Detection indicators

2.3 Detection methods

2.4 Statistical analysis

3 Results

3.1 Comparison of carotid AS among patients with different grades of LA

Table 3 Comparison of MMSE score among patients with different grades of LA ( χ ¯ ±s) Group LA degree score MMSE score LA-0 (n = 45) 0 47.4±6.53 LA-1 (n = 45) 2.1±0.8 37.5±8.41* LA-2 (n = 45) 4.7±1.2* 21.8±5.42* LA-3 (n = 45) 8.1±1.7* 14.4±6.36*

Conflict of interest

References

Table 3
Comparison of MMSE score among patients with different grades of LA ( $\bar{χ}$ ±s)

Group LA degree score MMSE score

LA-0 (n = 45) 0 47.4±6.53

LA-1 (n = 45) 2.1±0.8 37.5±8.41^*

LA-2 (n = 45) 4.7±1.2^* 21.8±5.42^*

LA-3 (n = 45) 8.1±1.7^* 14.4±6.36^*