Prevalence of hyperhomocysteinaemia, selected determinants and relation to hypertension severity in Northern-Nigerian hypertensives: the ABU homocysteine survey

Development of a chemiluminescent immunoassay based on magnetic solid phase for quantification of homocysteine in human serum

BACKGROUND

Homocysteine (HCY) is a sulfur-containing amino acid that is an independent or important risk factor for the occurrence of many chronic diseases and is one of the most important indicators for determining health risks. However, existing HCY detection methods do not meet the requirements of clinical diagnosis. Therefore, there is an urgent need to establish new detection methods to meet the needs of clinical detection.

RESULTS

In this study, we used the principle of competitive method to establish a new method for the determination of HCY in human serum using a chemiluminescent enzyme immunoassay in conjunction with a chemiluminescent assay instrument that uses magnetic microparticles as the solid phase of the immunoreaction. The established method achieved satisfactory results in terms of minimum detection limit, specificity, accuracy, and clinical application. The limit of detection was 0.03 ng/mL. The intra-assay coefficient of variation (CV) was 1.94-5.05%, the inter-assay CV was 2.29-6.88%, and the recovery rate was 88.60-93.27%. Cross-reactivity with L-cysteine ranged from 0.0100 to 0.0200 μmol/L, and cross-reactivity with glutathione ranged from 0.0100 to 0.200 μmol/L, all of which were less than the limit of detection (LoD) of this method. The linear factor R of this method was greater than 0.99.

CONCLUSIONS

In summary, the developed method showed a good correlation with the product from Abbott. A total of 996 clinical patients with cardiovascular diseases were evaluated using the method developed in this study.

Homocysteine, hyperhomocysteinemia, and H-type hypertension

Homocysteine (Hcy) is a sulphur-containing nonessential amino acid derived from the intermediate metabolites of methionine. Methionine is obtained from dietary proteins, such as poultry, meat, eggs, seafood, and dairy products. Abnormalities in Hcy metabolic pathways, deficiencies in dietary methionine, folate, and vitamins B12, B6, and B2 and genetic defects, polymorphisms, or mutations in Hcy metabolism-related enzymes may lead to an increase in plasma Hcy levels. Generally, a plasma Hcy level higher than 10 or 15 μmol/L has been defined as hyperhomocysteinemia (HHcy). An individual with essential hypertension complicated with HHcy is considered to have H-type hypertension (HTH). Currently, HHcy is considered a novel independent risk factor for various cardiovascular diseases. To provide a useful reference for clinicians, the research progress on Hcy, HHcy, and HTH in recent years was systematically reviewed here, with a focus on the source and metabolic pathways of Hcy, plasma Hcy levels and influencing factors, detection methods for plasma Hcy levels, relationship between Hcy concentration and hypertension, pathogenesis of HTH, cardiovascular complications of HTH, and treatment of HTH.

Intermediate-Term Prognostic Value of Homocysteine in Acute Coronary Syndrome Complicated with or without Hypertension: A Multicenter Observational Cohort Study

Background

As a classical biomarker associated with hypertension, the prognostic value of homocysteine (Hcy) in the intermediate-term outcome of acute coronary syndrome (ACS) remains controversial. This study aimed to investigate the role of homocysteine in ACS patients with different blood pressure statuses.

Methods

A total of 1288 ACS patients from 11 general hospitals in Chengdu, China, from June 2015 to December 2019 were consecutively included in this observational study. The primary endpoint was defined as all-cause death. Secondary endpoints included cardiac death, nonfatal myocardial infarction (MI), unplanned revascularization and nonfatal stroke. The patients in the hypertension group (n = 788) were further stratified into hyperhomocysteinemia (H-Hcy, n = 245) and normal homocysteinaemia subgroups (N-Hcy, n = 543) around the cut-off value of 16.81 µmol/L. Similarly, the nonhypertensive patients were stratified into H-Hcy (n = 200) and N-Hcy subgroups (n = 300) around the optimal cut-off value of 14.00 µmol/L. The outcomes were compared between groups.

Results

The median follow-up duration was 18 months. During this period, 78 (6.05%) deaths were recorded. Kaplan‒Meier curves illustrated that H-Hcy had a lower survival probability than N-Hcy in both hypertension and nonhypertension groups (p < 0.01). Multivariate Cox regression analysis revealed that H-Hcy was a predictor of intermediate-term mortality in ACS, regardless of blood pressure status.

Conclusions

Elevated Hcy levels predict intermediate-term all-cause mortality in ACS regardless of blood pressure status. This association could be conducive to risk stratification of ACS.

Clinical Trial Registration

The study was registered in the Chinese Clinical Trials Registry in China (ChiCTR1900025138).

Hyperhomocysteinemia and its relations to conventional risk factors for cardiovascular diseases in adult Nigerians: the REMAH study

BACKGROUND

Evidence linking homocysteine (Hcy) with cardiovascular diseases (CVD) or its risk factors are limited in a sub-Saharan black population.

OBJECTIVE

We set out to evaluate the association between Hcy and hypertension and other CVD risk factors in a population of adult Nigerians.

METHODS

Data of 156 adults aged 18-70 years was accessed from the North Central study site of the REmoving the MAsk on Hypertension (REMAH) study. Homocysteine, blood glucose and lipid profile in whole blood/serum were measured using standard laboratory methods. Hypertension was diagnosed if average of 5 consecutive blood pressure (BP) measurements obtained using a mercury sphygmomanometer was equal to or higher than 140 systolic and/or 90 mmHg diastolic or the individual is on antihypertensive medication. Hyperhomocysteinemia (HHcy) was defined as Hcy > 10 µmol/L.

RESULTS

Of the 156 participants, 72 (43.5%) were hypertensive, of whom 18 had HHcy. Subjects with HHcy were significantly (p < 0.05) older (41.5 vs. 40.6yrs), had lower HDL-cholesterol (0.6 vs. 0.8 mmol/L) and higher systolic (145.5 vs. 126.0 mmHg) and diastolic BP (92.9 vs. 79.6 mmHg), compared to those without HHcy. Intake of alcohol and a 1 yr increase in age were respectively and significantly (p < 0.05) associated with a 1.54 and 0.10 µmol/L increase in Hcy. In a multivariable model adjusted for age, sex and body mass index, a 1 µmol/L increase in Hcy, was associated with a 1.69 mmHg and 1.34 mmHg increase in systolic and diastolic pressure (p < 0.0001) respectively; and a 0.01 mmol/L decrease in HDL-cholesterol (p < 0.05).

CONCLUSION

HHcy occurs among hypertensive Nigerians and it is independently associated with age, HDL-cholesterol, systolic and diastolic BP.