What Are the Effects of Elevated Homocysteine?

Homocysteine, also known as homocysteine or homocysteine for short-blood homo, is a heterologous amino acid cysteine, which contains a Extra methylene (-CH2-).

Homocysteine

Homocysteine extra

In 1969, McCully found from autopsy of dead children with hereditary homocysteineuria that there was extensive arterial thrombosis and atherosclerosis (AS) pathological manifestations in the systemic circulation, and thus proposed hyperhomocysteinemia Hypothesis (hyperhomocysteinemia, HHCY) can lead to the hypothesis of atherosclerotic vascular disease. Since then, scholars from various countries have done a lot of research on the relationship between HCY and cardiovascular and cerebrovascular diseases. Hcy is a sulfhydryl-containing amino acid, which is mainly derived from dietary methionine. It is an important intermediate product in the metabolism of methionine and cysteine. It does not participate in protein synthesis itself. In the body, about 1/2 of Hcy and methyltetrahydrofolate are produced by methionine synthase reductase (MS), and methionine and tetrahydrofolate are produced. Tetrahydrofolate is produced at N5, N10-methylenetetrahydrogen. Folate reductase (Methylenetetralydrofolate, MTHFR) generates methyltetrahydrofolate; the remaining about 1/2 of Hcy pass through the sulfhydryl pathway, that is, Hcy and serine act in Cystathionine -synthase (CBS) Cystathionine is formed under the influence of cystathionine lyase, partly forms cysteine under the action of cystathionine lyase, and finally produces pyruvate, sulfuric acid and water. This process requires vitamin B6 as a coenzyme and serine hydroxymethyl transferase, and another part Homoserine. When the first two metabolic pathway disorders are caused by any reason, elevated Hcy generates homocysteine thiolactone (HTL) under the action of aminoacyl-tRNA synthetase. HTL is Hcy in aminoacyl-tRNA The reaction product formed during the process of editing or calibrating the synthetase belongs to an epithioester. Hcy can directly or indirectly cause damage to vascular endothelial cells, promote the proliferation of vascular smooth muscle cells, affect the oxidation of low density lipoprotein, enhance platelet function, and promote thrombosis.

The earliest detection of homocysteine was an amino acid analysis method. Ueland et al. Measured homocysteine in serum, and then improved it. At present, the commonly used methods include the following.

Isotope method : Method established in 1985 by Refsum et al. This method measures HCY concentration by condensing 14C-labeled adenosine with HCY, separating it by chromatography, and measuring the radiation intensity of liquid scintillation counting. This method has high sensitivity and strong specificity, but it is tedious to operate and has radioactive contamination.

Chromatography : In 1987, Stabler first reported the determination of homocysteine by gas chromatography-mass spectrometry. This method can be used for the simultaneous determination of cysteine, methionine, cystathionine and methylglycine. Although the sensitivity and specificity are good, the instrument is expensive and cannot be promoted. High-performance liquid chromatography (HPLC) is a relatively mature and widely used method. The disadvantages are the many variations in sample processing, chromatography conditions, sample detection, and quantification, making it difficult to standardize. Fiskertrand et al. First used fully automatic high performance liquid chromatography to determine HCY and thiol in plasma and urine in 1993. HPLC can be divided into a variety of methods based on the derivatization method (pre-column or post-column derivatization) and detection methods (fluorescence, electrochemistry). Accurate determination of homocysteine by HPLC requires excellent equipment, superb technical experience, and appropriate time to apply HPLC methods. In addition, the selection and preparation of internal quality control is also very important.

Immunological method : This method uses specific anti-S-adenosine homocysteine monoclonal technology and uses fluorescence polarization method or immunoassay to determine HCY. Abbott Corporation of America uses full-automatic chemiluminescence immunoassay technology, using Architect I2000SR instrument The detection principle of HCY is that about 1% of normal human plasma HCY exists in reduced form, 70% is combined with albumin, and 30% forms small molecular disulfide. Plasma specimens are reduced to the free HCY form (tHCY) by pretreatment with dithiothreitol-containing pretreatment solution (tHCY): tHCY is in the S-adenosyl-L-isotype half Cysteine (SAH) hydrolase and excess adenosine are converted to SAH; pre-diluted SAH mixture, anti-SAH monoclonal antibody, and labeled fluorescent S-adenosyl-L-cysteine tracer Incubate together, the instrument automatically detects the change of polarized light, and the total HCY level of the specimen can be measured. This method is fast, simple, and highly automated. It can reduce human error, has good accuracy and precision, and is suitable for most clinical laboratory applications.

lack of

High levels of homocysteine in the serum are

Although homocysteine does not affect bone density, it prevents

Studies have shown that high levels of homocysteine, the so-called homocysteineemia, can cause cognitive dysfunction in the human body, and severely lead to Alzheimer's disease and schizophrenia ^[2]

Homocysteine is converted from methionine, an important amino acid in the body. Because meat, cheese and other protein foods are particularly rich in methionine, we eat this methionine almost every day. The level of homocysteine in our body is called H score (H Score). H score can more accurately predict the risk of heart disease or stroke, and it can better predict the risk of dementia than genes. In fact, H-values can help predict more than 50 disease risks, including all causes of premature death. It can even tell you how fast you are aging. By reflecting vitamin B nutritional status, immune system function and brain condition, it can show whether the chemical status in the body is normal.

The lower the homocysteine concentration, the better your body can maintain the perfect biochemical balance, thus making you more perfect. This means more energy, better endurance and endurance, a clearer mind, less infections and better skin and weight control. Therefore, if you do not keep homocysteine concentrations low or within equilibrium, you will encounter the following ten problems:

Accelerated oxidation and aging

Damage your arteries

3. A weakened immune system

4. Brain damage and lower IQ

5. Increase pain, inflammation and blood clots

6. Susceptibility to cancer and detoxification

7. Accelerated aging brain

8. Hormone problems

9. Vitamin B deficiency

10. Lack of SAMe

Therefore, homocysteine is an important health indicator for humans.

A low-fat, fruit-and-vegetable diet can reduce homocysteine levels in the blood, reducing the risk of heart disease by 7-9%.

Homocysteine is an amino acid that is synthesized during protein metabolism in the body. The risk of heart disease and stroke is related to the increased levels of this amino acid in the blood. Some studies have found that group B vitamins such as folate in meat, seafood and green leafy vegetables can reduce homocysteine in the blood.

Dr Lawrence J. Appel, of the Johns Hopkins Medical Institute in Baltimore, said that by far most people believe that diet has some effect on traditional risk factors for heart disease, such as blood pressure and cholesterol. This trial confirmed that reducing homocysteine through the diet is also beneficial. This opens a new way for diet to prevent heart disease. The report of the study was published in the August 22nd issue of the American Heart Association's journal Circulation.

118 patients with moderate hypertension participated in the trial. Subjects ate the typical American diet (relatively less fruits and vegetables and dairy products), with 37% of calories coming from fat. After three weeks, subjects were divided into three groups. The first group continued the original diet; the second group switched to more fruits and vegetables and a small amount of dairy products; the last group ate a diet to prevent hypertension (DASH).

The DASH diet is rich in fruits and vegetables and low-fat dairy products; low in total and saturated fats; and contains about 400mg of folic acid, which is the recommended amount by the United States Department of Agriculture (USDA). DASH is a trial to study the effect of a healthy diet on lowering blood pressure.

As a result of the trial, those who still ate the "typical" diet had higher homocysteine levels at the end of the trial than at the beginning of the trial; the DASH diet group had lower homocysteine levels.

The results of this trial may explain the benefits of certain dietary patterns, such as the relationship between vegetarian diets and reduced risk of ischemic heart disease and stroke.

In the complex transformation process of homocysteine, there are several key substances that influence these reactions. They are vitamin B6, vitamin B12, and folic acid. At the same time, 99% of human homocysteine is metabolized in the kidney and 70% is eliminated by the kidney. With this in mind, it is not difficult to understand the cause of elevated homocysteine:

1. Genetic factors: genetic defects or mutations lead to lack of enzymes necessary for homocysteine metabolism.

2, the impact of nutritional status: inadequate intake of vitamin B6, vitamin B12, folic acid, resulting in lack of vitamins and folic acid in the body, can also cause homocysteine accumulation in the body.

3. Renal failure: In patients with nephropathy undergoing hemodialysis, the level of homocysteine in blood can reach 2 to 4 times that of normal people, and the probability of occurrence of vascular embolism symptoms is significantly increased.

4, some drugs such as carbamazepine, isoniazid, and some diseases such as malignant tumors, psoriasis, hypothyroidism, etc., can also lead to an increase in homocysteine.

In addition, lifestyle also affects the concentration of homocysteine in the blood, such as a large intake of coffee, alcohol, smoking, etc. can lead to an increase in homocysteine.

Who should be wary of elevated homocysteine? How to reduce homocysteine?

First, the most commonly seen patients with hypercysteine in the clinic are those with renal failure and multiple or long-term dialysis. For these patients, the homocysteine concentration in the plasma should be measured regularly. In the treatment of renal failure, some antioxidant drugs such as vitamin E and vitamin C are appropriately added. They can counteract the damage to the vascular endothelium caused by homocysteine through oxidation and play a certain role in protecting blood vessels.

In addition, some people who are malnourished due to unscientific diets or environmental factors are prone to B group

When we exercise or exercise only lightly, our livers produce creatine to help muscles contract. A by-product of creatine is homocysteine. Homocysteine is harmful in the body and needs to be eliminated to keep the body healthy. In this sense, long-term high-volume exercise is harmful to the body.

There are several ways our body can degrade homocysteine in the body. One method is by way of recovering methionine. Because homocysteine is produced in the body by methionine. "Where it comes from, where it returns" can effectively reduce homocysteine in the body

Ball and stick model

Within the concentration. We must have enough folic acid and vitamin B-12 in our bodies to keep the recycling job done well. Second, homocysteine can be converted into cysteine in the presence of vitamin B-6. There is another method to reduce the production of creatine in the body by supplementing creatine, thereby reducing the production of homocysteine in the body.