Investigation of plasma amyloid beta 1-42 levels and its correlation with some cardiovascular risk factors in people over forty years old

Objectives: Amyloid beta 1-42 (Aβ 1-42) is related to several disorders including nervous, cardiovascular and metabolic disorder. We investigated plasma Aβ 1-42 level and examined its correlation with some cardiovascular risk factors.

Journal of military pharmaco-medicine No7-2016 INVESTIGATION OF PLASMA AMYLOID BETA 1-42 LEVELS AND ITS CORRELATION WITH SOME CARDIOVASCULAR RISK FACTORS IN PEOPLE OVER FORTY YEARS OLD Nguyen Minh Hai*; Nguyen Minh Nui*; Ho Anh Son** SUMMARY Objectives: Amyloid beta 1-42 (Aβ 1-42) is related to several disorders including nervous, cardiovascular and metabolic disorder We investigated plasma Aβ 1-42 level and examined its correlation with some cardiovascular risk factors Subjects and methods: Level of Aβ 1-42 was measured in plasma of 40 people over forty years old without type diabetes mellitus and hypertension by ELISA method Results and conclusions: Average plasma Aβ 1-42 level was 98.88 ± 92.45 pg/mL, median was 65.49 pg/mL with wide range from 45.83 to 494.32 pg/mL There was no significant correlation between plasma Aβ 1-42 level and cardiovascular risk factors such as age, plasma lipids * Key words: Metabolic disorder; Amyloid beta INTRODUCTION Amyloid is a specific peptide family including aggregating beta chains Small, focal, clinically silent amyloid deposits in the brain, heart, seminal vesicles, and joints is a universal accompaniment of aging These results in amyloidosis, structural disorders, reduction and loss in function of various organs in the body The underlying molecular abnormalities may be either acquired or hereditary and about 20 different proteins can form clinically or pathologically significant amyloid fibrils in vivo Brain amyloid deposit is a major pathological feature of Alzheimer disease Islet amyloid deposits trigger type diabetes mellitus Amyloid also deposits in joints, peripheral arteries, kidneys Aβ 1-42 is one of amyloid molecular, which is considered to relate with different diseases such as Alzheimer’s disease, diabetes, cardiovascular diseases [2] Although many studies about Aβ 1-42 have been performed, its role and physical function is still unknown So far in Vietnam, there has been no investigation about the exact physical function of Aβ 1-42 Therefore, we carry out this study to: - Examine the level of Aβ 1-42 plasma in the people over 40 years old - Investigate whether there is any relationship between plasma Aβ 1-42 level and cardiovascular risk factors SUBJECTS AND METHODS Subjects * Selection criteria: Study was carried out on 40 people over forty years old without type diabetes mellitus and hypertension * 103 Hospital ** Military Medical University Corresponding author: Nguyen Minh Nui (minhnuinguyen@gmail.com) 35 Journal of military pharmaco-medicine No7-2016 Methods - Cross-sectional study without control group - All people were clinically and paraclinically examined by measuring weight, height, blood pressure, level of glucose, creatinine, acid uric, lipid in their blood Level of Aβ 1-42 plasma was measured by ELISA method in Physiopathology Department, Vietnam Millitary Medical University - Methods of Aβ 1-42 measurement [9]: + mL of whole bood was taken into tubes with anticoagulant (citrate) in the morning Afterward, the sample was centrifugated for 20 at 2,000 rpm Collect the supernatant carefully as plasma sample If precipitate was seen during reservation, the sample should be centrifugated again + The Microelisa stripplate provided in the ELISA kit has been pre-coated with an antibody specific to Aβ 1-42 Standards or samples were added to the appropriate Microelisa stripplate wells and combined to the specific antibody Then a Horseradish Peroxidase (HRP) - conjugated antibody specific for Aβ 1-42 was added to each Microelisa stripplate well and incubated Free components were washed away before adding the Chromogen solution A and Chromogen solution B to each well Blue only appreared in those wells that contain Aβ 1-42 and Horseradish peroxidase conjugated Aβ 1-42 antibody and then it turned yellow after addition of the stop solution The optical density is measured spectrophotometrically at a wavelength of 450 nm The optical density value is 36 proportional to the concentration of Aβ 1-42 The concentration of Aβ 1-42 in the samples is calculated by comparing the optical density of the samples to the standard curve * Statistical analysis: to initially explore the relationship between variable sets, scattergram blots using Microsoft Excell (2010), where a relationship was found Stata verson 12.0 was used to verify the statistical significances of the association Simple linear regression was initially used Pearson chi-square was used to determine the association between concentration of Aβ 1-42 plasma and baseline participant characteristics RESULTS Characteristics of the subjects 40 people included 24 males (60%) and 16 females (40%) Mean age was 54.38 ± 11.23 years Plasma Aβ 1-42 levels Table 1: Plasma Aβ 1-42 level Variable Male (n = 24) Level of Aβ 1-42 plasma (pg/ml) Mean ± SD Median (Min - max) 83.77 ± 58.17 64.46 (45.83 - 313.64) Female (n = 16) 121.55 ± 126.97 66.67 (47.59 - 494.32) Summarization 65.49 (45.83 - 494.32) 98.88 ± 92.45 Both mean and medium plasma Aβ 1-42 in male were not significantly lower than those in female (p > 0.05) Levels of Aβ 1-42 fluctuated from 45.83 pg/mL to 494.32 pg/mL Journal of military pharmaco-medicine No7-2016 Association between plasma Aβ 1-42 levels with age, blood glucose and acid uric levels Aβ 1-42 (pg/mL) * Association between plasma Aβ 1-42 levels and age: Figure 1: Correlation between plasma Aβ 1-42 levels and age No significant correlation between plasma Aβ 1-42 levels and age of participants was found (p > 0.05) A = 5.6765 * Glucose + 71.579 r = 0.043, p= 0.79 600 600 500 500 A = -0.311 * Uric + 209.48 r = 0.251, p = 0.11 Aβ 1-42 (pg/mL) Aβ 1-42 (pg/mL) * Association of plasma Aβ 1-42 level with blood glucose and acid uric levels: 400 300 200 100 400 300 200 100 0 Glucose (mmol/L) A 200 400 Acid uric (µmol/L) 600 B Figure 2: Correlation between plasma Aβ 1-42 levels and glucose (A), acid uric (B) levels Plasma Aβ 1-42 levels did not correlate with either glucose or acid uric levels (p > 0.05) 37 Journal of military pharmaco-medicine No7-2016 Association between plasma Aβ 1-42 levels with total cholesterol, HDL-C, LDL-C, and triglyceride levels 600 A = -7.332 * Triglyceride +114.19 r = -0.138, p = 0.43 600 500 500 Aβ 1-42 (pg/mL) Aβ 1-42 (pg/mL) A = -20.324 * Cholesterol + 208.69 r = -0.022, p = 0.61 400 300 200 100 400 300 200 100 0 Triglyceride (mmol/L) Cholesterol (mmol/L) A B A= 111.17 * HDL - 40.721 r = 0.327, p = 0.08 A = -37.177 * LDL + 222.65 r =-0.34, p = 0.44 600 600 500 500 Aβ 1-42 (pg/mL) Aβ 1-42 (pg/mL) 10 400 300 200 100 400 300 200 100 0 0.5 1.5 HDL-C (mmol/L) C LDL-C (mmol/L) D Figure 1: Correlation between plasma Aβ 1-42 levels, cholesterol (A), triglyceride (B), HDL-C (C) and LDL-C (D) No significant correlation of plasma Aβ 1-42 plasma levels with cholesterol, triglyceride, HDL-C and LDL-C was observed DISCUSSION Aβ 1-42 is supposed to relate to a variety of disorders such as Alzheimer’s disease, type diabetes mellitus In the body, Aβ 1-42 38 can be solute in cerebrospinal fluid and blood or deposits in brain, pancreas We investigated whether there were any associations between plasma Aβ 1-42 levels and cardiovascular risk factors Journal of military pharmaco-medicine No7-2016 In our study, the mean (±SD) and median plasma Aβ 1-42 were 98.88 ± 92.45 (pg/mL) and 65.49 (pg/mL) The concentration of Aβ 1-42 plasma fluctuated in a large range between 45.83 (pg/mL) and approximately 500 (pg/mL) It was interesting to note that participants who had the highest plasma Aβ 1-42 level had normal levels of lipid, glucose, acid uric in the blood with total cholesterol = 5.17 (mmol/L), HDL-C = 1.8 mmol/L, LDL-C = (mmol/L), LDL-C = (mmol/L), triglyceride = 0.54 (mmol/L), acid uric = 327 (µmol/L) Metti and his colleagues (2012) used Innogenetics INNO-BIA assays to measure plasma Aβ 1-42 level in 988 communitydwelling elders who suffer from diabetes, stroke, myocardial infarction and hypertension Mean age of these patients was 74.0 ± years The mean (±SD) and median of plasma Aβ 1-42 levels were 33.9 ± 9.7 and 32.83 (pg/mL) [7] The mean and plasma Aβ 1-42 levels in our study were both similar to Mehta and Metti’s findings Thus, the differences in plasma Aβ 1-42 levels in these studies were affected significantly by age In the study by Kelvin et al, mean (±SD) and medium of plasma Aβ 1-42 levels in a group of 18 healthy adults were 29.1 ± 18.1 (pg/mL) and 27 (pg/mL) These results were lower than our findings and the concentration of plasma Aβ 1-42 levels fluctuated in narrower range between 2.5 (pg/mL) and 62 (pg/mL) However, mean age of the participants in Kelvin’s research was 36, which was lower than the figure in our study [4] High plasma cholesterol, triglyceride and LDL levels, as well as low plasma HDL levels have long been known to be associated with cardiovascular risk factors and have been identified as significant risk factors for Alzheimer’s disease HDL has been shown to carry Aβ 1-42 in plasma and cerebrospinal fluid [1] Plasma HDL has been reported to be lower in patients with Alzheimer’s disease and is highly correlated with lower cognitive scores from these patients [1, 3] Many studies indicated that HDL which interact with Aβ 1-42 in plasma, can regulate Aβ 1-42 aggregation, degradation and toxicity [5, 8] Our study did not show significant associations between levels of total cholesterol, triglyceride, LDL-C or HDL-C and Aβ 1-42 levels This results were similar to those of Kelvin et al in 2005 [4] In 2000, Mehta and his colleagues conducted a study on the patients older than forty with Alzheimer’s disease and control subjects Levels of Aβ 1-42 plasma were measured by a sandwich enzymelinked immunosorbent assay Both the medium of plasma Aβ 1-42 levels in group of Alzheimer’s disease and control group were higher than the results of our study with 73 (pg/mL) (minimum = 25 pg/mL, maximum = 880 pg/mL) and 81 (pg/mL) (minimum = 25 pg/mL, maximum = 905 pg/mL), respectively The plasma Aβ 1-42 levels also fluctuated in a large range [6] However, our study was performed in healthy individuals Whether there is any correlation between Aβ 1-42 levels and cardiovascular risk factors in diabetic patients as well as in healthy people, which need to be investigated in the future 39 Journal of military pharmaco-medicine No7-2016 CONCLUSION The mean and medium of plasma Aβ 1-42 levels in people over forty years old were 98.88 ± 92.45 (pg/mL) and 65.49 (pg/mL) and plasma Aβ 1-42 levels fluctuated in a large range between 45.83 (pg/mL) and 494.32 (pg/mL) No correlations between Aβ 1-42 levels and several cardiovascular risk factors such age, plasma glucose, acid uric and lipids levels were observed REFERENCES Cole G M, Beech W, Frautschy S A et al Lipoprotein effects on Abeta accumulation and degradation by microglia in vitro J Neurosci Res 1999, 57 (4), pp 504-520 David A Warrell, Timothy M Cox, Firth JD Oxford Textbook of Medicine 4th Edition ed.: Oxford University 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Amyloid Proteins Methods in Molecular Biology: Humana Press 2012, pp.507-527  ... ± years The mean (±SD) and median of plasma Aβ 1-42 levels were 33.9 ± 9.7 and 32.83 (pg/mL) [7] The mean and plasma Aβ 1-42 levels in our study were both similar to Mehta and Metti’s findings... investigated in the future 39 Journal of military pharmaco-medicine No7-2016 CONCLUSION The mean and medium of plasma Aβ 1-42 levels in people over forty years old were 98.88 ± 92.45 (pg/mL) and 65.49... the differences in plasma Aβ 1-42 levels in these studies were affected significantly by age In the study by Kelvin et al, mean (±SD) and medium of plasma Aβ 1-42 levels in a group of 18 healthy