Application of theanine in prevention of occurrence of kidney injury of hypertensive patient

Abstract

The L-theanine provided by the invention is used for preparing medicines or health-care products for inhibiting or delaying kidney injury or preventing or treating chronic kidney diseases of hypertensive patients. According to the application disclosed by the invention, not only is the occurrence of the chronic kidney disease considered, but also the progress of the chronic kidney disease and early indexes such as glomerular filtration rate and urine microalbumin which can reflect kidney structure or dysfunction are evaluated, and the effects of the L-theanine on preventing or treating the chronic kidney disease of a hypertensive patient and inhibiting or delaying kidney injury are proved from multiple angles. The application proves that the L-theanine can inhibit or delay kidney injury, has the value of preventing and treating chronic kidney diseases of hypertensive patients, can reduce poor prognosis of the hypertensive patients, and has exploration significance on application of L-theanine finished products in health-care products or medicines in the future.

Description

Technical Field

[0001] The present invention belongs to the field of biomedicine, and specifically relates to the use of L-theanine in preparing a medicine or health product for inhibiting or delaying kidney damage in patients with hypertension, and the use of L-theanine in preparing a medicine or health product for preventing or treating chronic kidney disease in patients with hypertension. Background Art

[0002] Chronic kidney disease (CKD) refers to abnormalities in kidney structure or function that persist for more than three months. CKD is prevalent worldwide, with an estimated global CKD prevalence of 9.1% in 2017, affecting nearly 700 million people.

[0003] Hypertension is a risk factor for CKD. As an important risk factor for CKD, hypertension can aggravate kidney involvement, easily develop into end-stage renal disease (ESKD), and be more likely to die from CKD. The kidney damage caused by essential hypertension may have the following reasons: the smooth muscle cells of the renal blood vessels become myofibroblasts, migrate from the tunica media to the intima layer, and secrete collagen to induce thickening of the intima of the renal arterioles; glomerular contraction leads to glomerular sclerosis, resulting in a decrease in glomerular filtration rate; podocyte injury loop glomerular basement membrane cell death and exfoliation, the remaining glomeruli hypertrophy and compensatory high filtration, leading to increased urinary microalbumin; microvascular dysfunction leads to a hypoxic environment, causing tubulointerstitial fibrosis. The main clinical manifestations are distal tubular renal function damage (such as decreased urine concentration function, increased nocturia), mild urine changes (trace to mild proteinuria, mild microscopic hematuria), and often other target organ complications of hypertension. This pathogenesis is different from glomerulonephritis caused by acute and chronic inflammation, which is mainly characterized by glomerular function damage. However, there is currently no effective treatment for chronic kidney disease. To prevent the occurrence of CKD in hypertensive patients, it is urgent to find effective intervention measures to slow down or inhibit the occurrence and development of CKD.

[0004] A healthy lifestyle is the cornerstone of preventing cardiovascular and renal metabolic diseases. In addition to quitting smoking, limiting salt, and increasing exercise, the important role of diet has received widespread attention. As an important part of the diet, tea is one of the oldest and most popular beverages in the world. In a large-scale prospective study of the population by Mengyi Liu et al., it was observed that the intake of unsweetened tea was negatively correlated with the risk of new CKD, but the intake of sugary tea was not associated with the risk of new CKD [Journal of Global Health, 2023.13.4094.]. Yangchang Zhang et al. used the UK Biobank and CKDGen Consortium data for Mendelian randomization analysis and found that increased tea intake had a protective effect on CKD, glomerular filtration rate (eGFR), and proteinuria [Causal Association between Tea Consumption and Kidney Function: A Mendelian Randomization Study. Frontiers in Nutrition, 2022.9, 801591.]. However, Doetinchem et al. found in a cohort study of 4722 people aged 26 to 65 that tea intake was not associated with changes in eGFR [Coffee and Tea Consumption in Relation to Estimated Glomerular Filtration Rate: Results from the Population-Based Longitudinal Doetinchem Cohort Study. The American Journal of Clinical Nutrition, 2016. 103, 1370-1377.]. A cohort study of 12,428 elderly people in the Guangzhou Biobank also did not find an association between green tea or black tea and eGFR [Effects of Tea Consumption on Renal Function in a Metropolitan Chinese Population: The Guangzhou Biobank Cohort Study. Journal of Renal Nutrition, 2014. 24, 26-31.]. Therefore, current studies on the association between tea intake and CKD risk are still inconsistent. The main reason is that different varieties of tea contain different functional ingredients, and different functional ingredients such as tea polyphenols, amino acids, caffeine and other compounds have different potential effects on renal function.Previous studies have focused on tea polyphenols, the most abundant active substance in tea. However, the caffeine component in tea polyphenols may trigger nervous system reactions such as insomnia, palpitations and anxiety, which may limit its protective effect on the kidneys.

[0005] Theanine is a non-protein amino acid unique to tea leaves, accounting for 40%-60% of the total free amino acids in tea plants and 1%-2% of the weight of tea plant dry matter. It is considered to be the characteristic amino acid of tea leaves. Theanine is an amide compound. All natural theanine found in tea plants is classified as L-theanine. Theanine is highly water-soluble and has a molecular formula of C7H 14 N2O3, molecular weight 174.2, chemical structure is as follows Figure 1As shown. Theanine is mainly synthesized from glutamic acid and ethylamine in the root of the tea tree. Almost all L-theanine in the human body comes from drinking tea or taking L-theanine monomers orally. After theanine enters the body orally, it is absorbed by the small intestine through the sodium ion transport system. The cell membrane amino acid transporter of the intestinal mucosa can transport theanine according to the concentration gradient of sodium ions inside and outside the cell. Lisa et al. [Kinetics of L-Theanine Uptake and Metabolism in Healthy Participants Are Comparable after Ingestion of L-Theanine via Capsules and Green Tea. The Journal of Nutrition, 2012. 142, 2091-2096.] conducted a randomized crossover experiment on the metabolic flow of theanine in the body. The study found that after the subjects took L-theanine (100 mg) orally in the form of capsules or tea for 0.8 hours, the concentration of L-theanine in human plasma reached a peak of 24.3±5.7μmol / L (capsules) or 26.5±5.2μmol / L (tea), and the concentration of theanine in urine and plasma was equivalent after 24 hours. Due to the low content of theanine, there was little research on it in the early stage of discovery. In recent years, with the improvement of detection technology, the role of theanine has been gradually discovered. Studies have shown that L-theanine has many physiological functions and has many beneficial effects on human health. L-theanine has the effect of lowering blood pressure. A crossover, randomized, placebo-controlled study found that oral administration of 200 mg of L-theanine can reduce anxiety levels in patients compared with placebo, and reduce blood pressure in adults with high stress reactions. This potential to lower blood pressure may be that L-theanine indirectly reduces stress, inhibits cortical nerve excitation, and thus weakens sympathetic nerve activity, achieving the effect of lowering blood pressure. Other studies have found that L-theanine changes circadian rhythm genes involved in the remodeling of vascular smooth muscle, and maintains the physiological contraction and relaxation of smooth muscle by regulating calcium-dependent and calcium-sensitive pathways, thereby having a positive effect on vasodilation. L-theanine can eliminate the increase in blood pressure caused by caffeine. The mechanism by which L-theanine regulates blood pressure levels may also be related to inhibiting NADPH oxidase activity and reducing reactive oxygen in the cardiovascular system. Previous studies have shown that habitual intake of more than 120 ml of green tea or oolong tea per day is associated with a reduced risk of hypertension, which has a positive effect on vasodilation, leading to changes in vascular tension and blood pressure. However, glutamic acid, the hydrolysis product of theanine, has not been found to have a blood pressure-lowering effect even though it has a similar structure. L-theanine not only has the effect of lowering blood pressure, but also has the effects of protecting brain nerve cells, resisting fatigue, assisting in tumor inhibition, lowering blood lipids, enhancing memory, enhancing immunity, improving premenstrual syndrome, and anti-aging.However, there are currently no studies reporting on the effects of L-theanine on renal damage in patients with hypertension and its role in preventing or delaying the occurrence of kidney disease in patients with hypertension. Summary of the invention

[0006] The inventors discovered the correlation between L-theanine and kidney damage in hypertensive patients during the process of studying the risk of chronic kidney disease development in hypertensive patients.

[0007] The present invention uses metabolomics technology to detect urine L-theanine in 487 hypertensive patients from a multicenter long-term follow-up cohort study, the Chinese Multi-provincial Cohort Study (CMCS). Through an 8-year follow-up study, the association between L-theanine and the risk of chronic kidney disease in hypertensive patients was explored, excluding the influence of blood pressure and antihypertensive drugs. L-theanine was found as a metabolic biomarker, and its increased level was associated with a reduced risk of chronic kidney disease in hypertensive patients. The present invention further explored the role of L-theanine in preventing the risk of progression of chronic kidney disease in hypertensive patients, and the results showed that high levels of L-theanine were associated with a reduced risk of progression of chronic kidney disease in hypertensive patients. The present invention found that L-theanine can also prevent abnormal glomerular filtration rate levels / reduced glomerular filtration rate / abnormal urinary microalbumin levels / increased urinary microalbumin in hypertensive patients. In summary, L-theanine can prevent kidney damage in hypertensive patients, has the value of alleviating and inhibiting kidney damage in hypertensive patients, and can reduce the adverse prognosis of hypertensive patients.

[0008] Therefore, the object of the present invention is to provide a new use of L-theanine in inhibiting or delaying kidney damage in hypertensive patients and preventing or treating chronic kidney disease in hypertensive patients.

[0009] In one aspect, the present invention provides the use of L-theanine in preparing a medicine or health product for inhibiting or delaying kidney damage in patients with hypertension.

[0010] Furthermore, the kidney damage includes kidney structure or function disorder.

[0011] Furthermore, the kidney damage includes abnormal kidney function related to glomerular filtration rate, structural damage related to urinary microalbumin, abnormal blood or urine components, and abnormal imaging examinations.

[0012] Furthermore, the kidney damage includes abnormal glomerular filtration rate levels.

[0013] Furthermore, the kidney damage includes a decrease in glomerular filtration rate.

[0014] Furthermore, the kidney damage includes abnormal urine microalbumin levels.

[0015] Furthermore, the kidney damage includes elevated urinary microalbumin.

[0016] In another aspect, the present invention provides use of L-theanine in preparing a medicine or health product for preventing or treating chronic kidney disease in patients with hypertension.

[0017] Furthermore, the chronic kidney disease in hypertensive patients includes the occurrence of chronic kidney disease and the progression of chronic kidney disease.

[0018] Multiple clinical variables were introduced into the model exploring the effect of L-theanine, including age, sex, BMI (body mass index), smoking, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting blood glucose, systolic blood pressure, eGFR (estimated glomerular filtration rate), urine ACR (ratio of urine microalbumin to urine creatinine), and the use of antihypertensive drugs, hypoglycemic drugs and statins.

[0019] The data collection involves the collection of physical examination information of hypertensive patients, urine sample collection, urine metabolomics testing, and the occurrence and development of chronic kidney disease eight years later.

[0020] The incidence of chronic kidney disease in hypertensive patients with high levels of L-theanine after eight years is 0.80 standard deviation times the incidence of chronic kidney disease in the low-level group. The incidence of chronic kidney disease progression in hypertensive patients with high levels of L-theanine after eight years is 0.79 standard deviation times the incidence of chronic kidney disease progression in the low-level group. The occurrence of abnormal glomerular filtration rate in hypertensive patients with high levels of L-theanine after eight years is 0.73 standard deviation times the incidence of abnormal glomerular filtration rate in the low-level group. The occurrence of abnormal ratio of urine microalbumin to urine creatinine in hypertensive patients with high levels of L-theanine after eight years is 0.77 standard deviation times the incidence of abnormal ratio of urine microalbumin to urine creatinine in the low-level group. The occurrence of decreased glomerular filtration rate in hypertensive patients with high levels of L-theanine after eight years is 0.74 standard deviation times the incidence of decreased glomerular filtration rate in the low-level group. In hypertensive patients with high levels of L-theanine, the incidence of an increase in the ratio of urine microalbumin to urine creatinine after eight years was 0.77 standard deviation times the incidence of an increase in the ratio of urine microalbumin to urine creatinine in the low level group.

[0021] The present invention not only considers the occurrence of chronic kidney disease, but also evaluates the progression of chronic kidney disease, as well as glomerular filtration rate and urine microalbumin, which are early indicators that can reflect kidney structure or dysfunction, and proves from multiple angles the role of L-theanine in preventing or treating chronic kidney disease in hypertensive patients, and inhibiting or delaying kidney damage in hypertensive patients. The present invention proves that L-theanine can inhibit or delay kidney damage in hypertensive patients, has the value of preventing and treating chronic kidney disease in hypertensive patients, can reduce the adverse prognosis of hypertensive patients, and has exploratory significance for the future application of L-theanine finished products in health products or medicines. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The chemical structure of L-theanine.

[0023] Figure 2 To investigate the association between L-theanine and different types of renal damage in patients with hypertension. DETAILED DESCRIPTION

[0024] The present invention is further described in detail by the following examples, but it should be understood that the present invention is not limited by the following contents.

[0025] Example: Metabolomics technology was used to detect L-theanine in the urine of hypertensive patients, and it was found that people with higher L-theanine levels were less likely to develop renal damage and chronic kidney disease in the future.

[0026] 1. Patient inclusion criteria and follow-up strategy

[0027] The CMCS study (China Multi-province Cardiovascular Disease Cohort Study) is a multi-center, multi-time point, long-term follow-up cohort study. All investigators are from community residents, and questionnaire information collection, physical examinations, and laboratory tests are all implemented in accordance with the unified standards of the CMCS.

[0028] This study selected 487 hypertensive patients who participated in two surveys with an interval of 8 years.

[0029] Hypertension was defined as the average of three blood pressure measurements, systolic / diastolic blood pressure ≥140 / 90 mmHg or taking antihypertensive drugs within two weeks before the survey.

[0030] Chronic kidney disease was defined as an estimated glomerular filtration rate (eGFR) ≥

[0031] 60ml / min / 1.73㎡ and urine ACR (ratio of urine microalbumin to urine creatinine) <30mg / g. During re-examination, eGFR <60ml / min / 1.73㎡ or urine ACR ≥30mg / g.

[0032] Progression of chronic kidney disease is defined as: a decrease in eGFR level and / or an increase in urine ACR level. A decrease in eGFR level means an increase in GFR stage and a decrease in eGFR ≥ 25% from the baseline value or a continuous decrease in eGFR rate greater than 5 ml / min / 1.73 m2 per year; an increase in urine ACR level means an increase in urine ACR stage or an increase in urine ACR > 30% from the baseline value.

[0033] The cohort study of the present invention was designed and implemented in accordance with the principles of the Declaration of Helsinki and approved by the Ethics Committee of Beijing Anzhen Hospital Affiliated to Capital Medical University, and written informed consent was obtained from all subjects.

[0034] 2. Collection of basic information of patients with hypertension:

[0035] 1. Blood sample collection: The subjects have to fast for more than 12 hours, and blood is collected from the elbow vein. Blood laboratory tests will be performed on the day of the investigation.

[0036] 2. Urine specimen collection: Collect mid-morning spot urine from the subject, a portion of which will be tested in the urine laboratory on the same day, and the remaining specimens will be packaged and placed in a -80℃ refrigerator for long-term storage.

[0037] 5. Laboratory testing methods:

[0038] It mainly includes the detection of biochemical indicators such as serum creatinine (Cr), urine creatinine (Urine Creatinine), albumin (Albumin, Alb), fasting blood glucose (FBG), glycosylated hemoglobin (HemoglobinA1C, HbA1c). All the above indicators are tested by the laboratory department of Beijing Anzhen Hospital on the day of blood collection, which meets the quality control standards of the clinical inspection center of the Ministry of Health.

[0039] 1) Determination of serum Cr: The Cr determination kit of Sekisui Medical Reagent Co., Ltd. of Japan was used, and the quinone pigment colorimetric liquid enzyme reagent was used for the determination of serum Cr. The detection equipment was Olympus AU5400 automatic biochemical analyzer.

[0040] 2) Urine creatinine determination: The reagent of Beckman Coulter was used to determine urine creatinine by the picric acid colorimetric method, and the detection equipment was Beckman Coulter DXC880.

[0041] 3) Urinary albumin determination: Urinary albumin was determined using a kit from Desay Diagnostics (Shanghai) Co., Ltd. using the immunoturbidimetric endpoint method.

[0042] 3. Metabolomics testing of urine samples from patients with hypertension:

[0043] Metabolomics test samples came from urine samples frozen at -80°C at baseline and were slowly thawed for non-targeted metabolomics testing.

[0044] (I) Metabolomics detection instruments: AB Triple TOF 6600 mass spectrometer (AB SCIEX), Agilent 1290 Infinity LC ultra-high pressure liquid chromatograph (Agilent), low temperature high-speed centrifuge (Eppendorf 5430R), chromatographic column: Waters, ACQUITY UPLC BEH Amide 1.7 μm, 2.1 mm × 100 mm column

[0045] (II) Urine sample extraction method: Take an appropriate amount of sample and add it to precooled methanol / acetonitrile / water solution (2:2:1, v / v), vortex mix, low-temperature ultrasonic for 30 min, let stand at -20℃ for 10 min, centrifuge at 14000g and 4℃ for 20 min, take the supernatant and vacuum dry, add 100 μL acetonitrile aqueous solution (acetonitrile: water = 1:1, v / v) for re-dissolution for mass spectrometry analysis, vortex, centrifuge at 14000g and 4℃ for 15 min, and take the supernatant for sampling and analysis.

[0046] (III) Chromatography-mass spectrometry analysis In this experiment, Agilent 1290 Infinity LC ultra high performance liquid chromatography system (UHPLC) HILIC ultra high performance liquid chromatography-AB Triple TOF 6600 tandem time-of-flight mass spectrometry (UHPLC-Q-TOF MS) was used for high-resolution non-targeted metabolomics analysis.

[0047] 4. Investigation plan for review after eight years:

[0048] The basic information collected was the same as that at baseline, including the methods used for blood and urine biochemical tests.

[0049] 5. Data Statistical Analysis

[0050] According to the occurrence of chronic kidney disease in hypertensive patients at the time of reexamination, the subjects were divided into the new chronic kidney disease group and the non-chronic kidney disease group / eGFR abnormal level group and the non-eGFR abnormal level group / UACR abnormal level group and the non-UACR level group / CKD progression group and the non-CKD progression group / eGFR reduced level group and the non-eGFR reduced level group / UACR increased level group and the non-UACR increased level group. In order to further analyze the association between metabolites and kidney damage, this study used modified Poisson regression analysis. The model takes into account potential confounding factors: age, gender, BMI (body mass index), smoking, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting blood glucose, systolic blood pressure, eGFR (estimated glomerular filtration rate), urine ACR (ratio of urine microalbumin to urine creatinine) at baseline, and the use of antihypertensive drugs, hypoglycemic drugs and statins. The relative risk of L-theanine and different degrees of kidney damage was obtained by the above method, and a forest map was drawn ( Figure 2 ).

[0051] VI. Correlation analysis between theanine and CKD occurrence / abnormal eGFR level / abnormal UACR level / CKD progression / decreased eGFR level / increased UACR level

[0052] The present invention performs correlation analysis on L-theanine and various kidney damage types in hypertensive patients, and adjusts related covariates. According to calculations, the incidence of chronic kidney disease in hypertensive patients with high levels of L-theanine after eight years is 0.80 standard deviation times the incidence of chronic kidney disease in the low-level group, and the RR value is 0.804 (95% confidence interval is 0.711-0.901). The incidence of chronic kidney disease progression in hypertensive patients with high levels of L-theanine after eight years is 0.80 standard deviation times the incidence of chronic kidney disease progression in the low-level group, and the RR value is 0.795 (95% confidence interval is 0.707-0.894). The occurrence of abnormal glomerular filtration rate in hypertensive patients with high levels of L-theanine after eight years is 0.73 standard deviation times the incidence of abnormal glomerular filtration rate in the low-level group, and the RR value is 0.730 (95% confidence interval is 0.540-0.987). The abnormal ratio of urine microalbumin to urine creatinine in hypertensive patients with high levels of L-theanine after eight years is 0.77 standard deviation times the incidence of abnormal ratio of urine microalbumin to urine creatinine in the low-level group, and the RR value is 0.772 (95% confidence interval is 0.667-0.893). The decrease in glomerular filtration rate in hypertensive patients with high levels of L-theanine after eight years is 0.74 standard deviation times the incidence of decrease in glomerular filtration rate in the low-level group, and the RR value is 0.744 (95% confidence interval is 0.572-0.967). The increase in the ratio of urine microalbumin to urine creatinine in hypertensive patients with high levels of L-theanine after eight years is 0.77 standard deviation times the incidence of increase in the ratio of urine microalbumin to urine creatinine in the low-level group, and the RR value is 0.773 (95% confidence interval is 0.675-0.885).

[0053] In order to eliminate the influence of blood pressure and antihypertensive drugs, the present invention adjusted the blood pressure level and antihypertensive drugs in the analysis, and found that L-theanine was still significantly correlated with various types of kidney damage in hypertensive patients.

[0054] The present invention further studied L-theanine and kidney damage in normotensive individuals and found that high levels of L-theanine were not associated with the incidence of chronic kidney disease (RR value was 1.073, 95% confidence interval was 0.844-1.364) and the incidence of chronic kidney disease progression (RR value was 1.041, 95% confidence interval was 0.820-1.323) in normotensive individuals over an eight-year period.

[0055] In summary, the present invention proves that L-theanine can alleviate chronic kidney disease and various types of early kidney damage in hypertensive patients. L-theanine has great significance for preventing chronic kidney disease and kidney damage in hypertensive patients, improving their poor prognosis, and developing drugs or health products containing L-theanine in the future for preventing and treating chronic kidney disease in hypertensive patients.

Claims

1. Use of L-theanine in the preparation of medicines or health products for inhibiting or delaying kidney damage in patients with hypertension.

2. The use according to claim 1, characterized in that The kidney damage includes kidney structure or function disorder.

3. The use according to claim 1 or 2, characterized in that The kidney damage includes abnormal kidney function related to glomerular filtration rate, structural damage related to microalbuminuria, abnormal blood or urine components, and abnormal imaging examinations.

4. The use according to claim 1 or 2, characterized in that: The kidney damage includes abnormal glomerular filtration rate levels.

5. The use according to claim 1 or 2, characterized in that: The kidney damage includes a decrease in the glomerular filtration rate.

6. The use according to claim 1 or 2, characterized in that: The kidney damage includes abnormal levels of urine microalbumin.

7. The use according to claim 1 or 2, characterized in that: The kidney damage included elevated urine microalbumin.

8. Use of L-theanine in the preparation of medicines or health products for preventing or treating chronic kidney disease in patients with hypertension.

9. The use according to claim 4, characterized in that: The chronic kidney disease in hypertensive patients includes the occurrence of chronic kidney disease and the progression of chronic kidney disease.

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