We all know that the kidney is an important organ in the human body. Its basic function is to produce urine to remove metabolites and certain wastes and poisons from the body, while retaining water and other useful substances through reabsorption. The kidney also has endocrine functions and is the degradation site of some of the body’s endocrine hormones and the target organ of extra-renal hormones. These functions of the kidney ensure the stability of the body’s internal environment and enable normal metabolism.
Under normal circumstances, when some metabolites and wastes of the body flow into the kidneys with the blood, the kidneys will play a clearing effect through filtration and form urine into the bladder, and also remove the excess water and wastes, while the filtered blood will continue to circulate in the body. If there is a problem with the kidneys and this circulatory process does not go on smoothly, you are in trouble.
Proteinuria is the most important and intuitive clinical manifestation of various kidney diseases, as well as an important risk factor for the progression of chronic kidney disease (CKD), and its severity is closely related to the prognosis of the disease.
The amount of protein in the urine of a healthy person is very small and should be negative when tested according to existing testing standards. However, if the person has certain problems, such as kidney disease, proteinuria may be present.
Also, you may have heard the term massive proteinuria versus microproteinuria. By massive proteinuria, it usually means that the protein level in urine routine is more than 3+ and the quantitative urine protein is more than 3.5 grams/24 hours. So much protein leaks out from the urine that it can easily cause nephrotic syndrome. Since there are many causes of massive proteinuria, it is necessary to be hospitalized for a detailed examination and, if necessary, a renal puncture to clarify the type of pathology.
As for microproteinuria, it refers to the presence of small amounts of albumin excretion in the urine. The rate of excretion is usually measured clinically to understand the condition of early kidney lesions. The rate of albumin excretion in normal human urine is no more than 20 micrograms/minute or 30 mg/day. If the albumin excretion in urine reaches 20-200 micrograms/minute or 30-300 mg/24 hours, the urine routine examination is still negative at that time, so it is called microproteinuria. It is the early clinical manifestation of diabetic nephropathy. In addition to diabetic nephropathy, hypertension, fever and strenuous exercise can also cause microproteinuria. Recent studies have found that the degree of microproteinuria is also associated with cardiovascular lesions and is an important predictor of poor prognosis of cardiovascular lesions.
Proteinuria and podocytes Our glomerular filtration membrane consists of five layers from the inside out, and lesions in any of these layers will affect the integrity of the filtration membrane. There is one thing in particular that we should mention here, and that is the podocyte.
This cell has nothing to do with your feet, but it is very important for the kidneys. A large number of studies have concluded that podocyte damage is central to glomerular damage, and when we have podocyte damage and proteinuria formation due to various causes, such as immune, inflammatory, toxic, infectious, metabolic, environmental, genetic background, etc., our kidneys will also have problems.
We have discussed in detail the mechanism of early proteinuria production, especially the role of podocyte injury, and the mechanism of proteinuria promoting kidney damage, and proposed a new mechanism of “proteinuria causing tubulointerstitial inflammation and promoting tubulointerstitial inflammation and fibrosis formation”, which is also the mechanism of chronic This is a key mechanism for the development of chronic kidney disease and the formation of uremia, which provides an important theoretical basis for the early prevention and treatment of chronic kidney disease.
On this basis, we have found a new method to detect the progression of chronic kidney disease by using urine mRNA examination, which provides a new means for early clinical diagnosis of chronic kidney disease. Since proteinuria is not only the main symptom of various types of chronic kidney disease in its early stages, but also a key factor promoting accelerated deterioration of kidney function, regular urine examination is essential, especially for patients with high-risk diseases such as hypertension, diabetes and atherosclerosis. Once proteinuria (including albuminuria) is detected, they should receive regular and active treatment and intervention, and maintain strict follow-up.
Proteinuria can be real or fakeProteinuria can be real or fake? You may find it unbelievable, but pseudoproteinuria does exist in clinical practice.
Pseudoproteinuria is commonly seen in the following cases.
1, urine mixed with blood, pus, inflammatory or tumor secretions, as well as menstrual blood and leukorrhea, when the test result may be positive.
2, urine can be placed for a long time or after cooling, salt crystals can be precipitated, making the urine white and cloudy, which can be easily mistaken for protein urine, but warming or adding a little acetic acid can make the cloudy urine turn clear.
3, urine mixed with semen or prostate fluid, or lower urethra inflammatory secretions, etc., urine protein reaction can be positive.
4.Lymphatic urine, which may be celiac and contain less protein.
5, Some drugs may make the urine cloudy similar to proteinuria, but the qualitative protein reaction is negative.
These can be ruled out with the identification of the professional staff in the laboratory.
CKD is not far from you The reason we pay so much attention to proteinuria is because of its close association with various types of kidney diseases, especially chronic kidney disease (CKD). However there are still many people who feel that CKD is still very far away from them.
In fact, it is not. In recent years, the incidence of kidney disease has increased significantly, but most patients do not know that they have the disease at an early stage, so it can be said that kidney disease is the most “camouflaged” and most easily ignored by people, and its early prevention and treatment must be of great concern to the public and the community.
Currently, the prevalence of chronic kidney disease is not low, according to data previously published in the authoritative medical journal “The Lancet”, the current prevalence of chronic kidney disease in China’s adult population reached 10.8%, while the awareness rate is only 12.5%. Our survey results show that the prevalence of chronic kidney disease in Jiangsu is around 12%, which is basically consistent with the national survey results; and the prevalence of chronic kidney disease (CKD) can be as high as 32.3% among people over 60 years old.
Patients with various metabolic diseases, including hypertension and diabetes, are at high risk for CKD, but these patients may be concerned about their cardiovascular health, but rarely think about checking whether their kidneys are well. In addition, drug abuse in Chinese patients with CKD is very serious, which is also a unique risk factor that needs attention.