Albumin it's a protein produced by liver, has important functions such as maintaining the balance of body fluids and the transport of substances in the blood. The feedback from low albumin (hypoalbuminemia) is usually indicative of malnutrition you hate liver disease or kidney. THE symptoms of low albumin there are many, including edema, weight loss and fatigue.
How is albumin produced? Albumin it is a protein plasma produced in the liver cells, the hepatocytes. A certain amount of albumin can also be introduced with the diet through foods such as milk or the albumen (the white of the egg) from which among other things it takes its name. Albumin it has a very high molecular weight, equal to 69 kD (69,000 daltons) and constitutes almost two thirds (over 60%) of all circulating blood proteins.
The concentration of albumin in the blood is called albuminemia and is measured by a blood test called protein electrophoresis, which is a test that measures the various proteins present in the blood by dividing them according to their size and their molecular weight. Albumin has very important functions for our body, and we realize this when its values are reduced and a series of rather important disorders appear.
Functions and mechanism of action of albumin
What are the roles that albumin has in our body? What is albumin for? Here are the main ones functions of albumin:
- Regulation of oncotic pressure and regulation of homeostasis of body fluids between the intravascular and extravascular compartment
- Transport of substances in the blood
- Chelating function of toxins and waste substances
- Antioxidant function
- Regulation of acid base balance, pH buffer action.
- Modulating activity of the coagulation function, having an anticoagulant and antiplatelet action depending on the situation.
First we must understand that albumin is the key protein for regulating and maintaining balance oncotic pressure (osmotic pressure), i.e. the concentration of substances necessary for retaining fluids within blood vessels and to maintain the right concentration towards the liquids present in the peripheral tissues (over 80% of the oncotic pressure in the plasma is secondary to albumin). In a nutshell, albumin is like a "sponge" or a "magnet" which, thanks to its negative membrane charges, retains positively charged ions and prevents body fluids from accumulating in excess in peripheral tissues.
In fact, one of the first symptoms that appear consequently to a reduction of blood albumin values is the appearance of edema i.e. accumulation of fluid in the body tissues, and especially in the legs, ankles and feet (declining edema). This is due to the water retention secondary to the "escape" of liquids from the arteries and veins towards the interstitial tissues and body cavities (the liquids that accumulate in the abdominal cavity are called periteonal effusion or ascites, while the fluids that accumulate in the pleural cavities around the lungs are called pleural effusion.
Another important function that albumin has is that of transport of substances in the blood. In fact, albumin is the main vehicle for other proteins in the blood vessels, also allowing molecules that normally would not be able to dissolve in the blood (for example fat-soluble substances, soluble in fat but not in H2O) to be conveyed in the various body tissues.
The main substances carried by albumin in the blood are
- Hormones, such as thyroid hormones and steroids
- Free fatty acids,
- Unconjugated bilirubin, or indirect bilirubin
- Mineral salts such as calcium ions (Ca 2+)
- Drugs and their metabolites.
Another fundamental function of albumin is that ofacid-base balance, with the maintenance of a neutral pH in our body. In fact, albumin is able, within certain limits, to buffer both temporary increases in plasma acidity (which would tend to lower the pH), and temporary increases in body basicity, which would tend to raise the pH.
Albumin also has an important role antioxidant function is chelating . In fact, it can bind free radicals derived from nitric oxide and other toxins and waste substances of the body, often substances responsible for an increase in the inflammatory picture and systemic vasodilation. In medical terms it is therefore said that albumin acts as free radical scavenger.
Low Albumin Causes - Causes of hypoalbuminemia
What does it mean to have low albumin? What does hypoalbuminemia mean? The feedback from low albumin or hypoalbuminemia it can be linked to a production defect or to an increased loss of this protein.
Reduced albumin production can be caused by a liver problem or the lack of the "bricks" necessary for its synthesis, as in malnutrition and in situations ad increased catabolism.
In the case of a low albumin for increased loss, this can occur in the kidney (nephrotic syndrome), in the intestine or in the skin, in the case of burns or major wounds.
Let's analyze all the possible ones one by one causes of low albumin:
- Liver cirrhosis by viruses such as HBV or HCV
- Exotoxic liver cirrhosis, i.e. secondary to alcohol abuse
- Cirrhosis of the liver secondary to iron overload, for example in hemochromatosis
- Cirrhosis of the liver secondary to copper accumulation, as in Wilson's disease
- Primary biliary cirrhosis or, in the new definition, biliary cholangitis
- Sclerosing cholangitis
- Cirrhosis secondary to autoimmune hepatitis
- Cirrhosis secondary to chronic right heart failure
- Cirrhosis secondary to alpha1-antitrypsin deficiency
- Alcoholism even without underlying cirrhosis
- Hepatic failure secondary to ingestion of drugs or hepatotoxic fungi (paracetamol intoxication, amanita)
- Hepatic insufficiency in the course of acute alcoholic intoxication
- Hepatic failure secondary to acute viral hepatitis, such as acute hepatitis B, hepatitis E and hepatitis A
- Hepatocarcinoma: it is the main tumor that develops in the liver and is very rare in people with healthy liver but unfortunately very common in people who already have cirrhosis
- Secondary liver injury, such as metastases from another non-hepatic tumor. The tumors that metastasize to the liver most frequently are colon, prostate and pancreas.
- Chronic renal failure even without albuminuria
- Primary nephrotic syndrome, is the loss of at least 3.5 g of protein daily in the urine, is linked to kidney disease such as glomerulonephritis or atherosclerotic damage (secondary to smoking, hypercoleterolemia, hypertriglyceridemia, diabetes mellitus). Nephrotic syndrome is almost always accompanied by chronic renal failure.
- Secondary nephrotic syndrome, linked to systemic diseases that also involve the kidney, such as systemic lupus erythematosus (SLE), multiple myeloma (plasmacytoma) or amyloidosis.
- Nephritic syndrome: is a condition characterized by loss of protein (proteinuria) and albumin (albuminuria) in the urine, but without reaching the 3.5 g of protein lost per day. Otherwise it has the same causes as the nephrotic syndrome.
- Chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis
- Protein-dispersing enteropathies, such as intestinal parasites, salmonellosis, parvovirus infection
- Hematological neoplasms (leukemias and lymphomas)
- Solid tumors
- Unbalanced low protein diet (low protein diet)
- Chronic pancreatitis
Let us now look in detail at the various mechanisms by which serum albumin levels decrease.
Hepatic causes of low albumin
The liver is the organ that produces the albumin protein. In the course of liver disease, hepatocytes will have difficulty producing the albumin necessary to maintain normal values in the blood. There cirrhosis of the liver it is by far the most common cause of all those listed.
Low albumin from increased renal loss
Any pathology that damages the kidney can be a cause of low albumin. Normally, in fact, albumin being a large protein with a negative electrical charge, cannot pass the membrane of the renal glomerulus. When this membrane is damaged instead part of the circulating albumin can pass and no longer be reabsorbed, ending up eliminated with the urine, this is particularly evident in nephrotic syndrome, that the condition in which more than 3 grams of protein are lost per day in the urine and which represents the end stage of many glomerulonephritis, tubulopathies and severe chronic renal failure.
Low albumin from increased intestinal loss
Albumin is absorbed in the intestine if the cells and enzymes of the intestinal wall are functioning properly. In case of intestinal disease, such as chronic inflammatory bowel diseases, Crohn's disease and ulcerative colitis, or in case of desperate protein enteropathies, such as bacterial intestinal infectious diseases such as viral salmonellosis with parvovirus or parasite I can, this does not happens. Protein absorption will in fact be compromised and at the same time proteins will be lost from the damaged intestinal wall, most of which consists of albumin.
Low albumin secondary to malnutrition or malnutrition
The liver needs an adequate supply of amino acids to produce albumin. In the case of malnutrition as occurs for example in alcoholics and the homeless, or malnutrition as occurs in third world populations, the reduced intake of amino acids and proteins in the diet prevents the liver tissue from producing adequate levels of albumin.
Low albumin from increased protein catabolism
There are also situations of increased catabolism, that is when, while eating normally, our body burns a high amount of nutrients, resulting in difficulty in producing proteins and often with degradation of already existing proteins to cope with accelerated metabolism (protein catabolism ). This is the case of neoplasms: tumor tissue replicates very quickly and consumes a good part of the proteins introduced in the diet. Also in this case the protein production will be insufficient to maintain the correct blood levels of albumin.
Low albumin in pregnancy
Even in pregnancy, albumin levels may be below normal. This is normally due to the haemodilution that occurs during gestation, i.e. the increase in body fluids that dilutes the dissolved substances then internal. In any case, if the finding of low albumin is associated with other symptoms, the picture must certainly be investigated with other analyzes or diagnostic tests.
Other causes of reduced albumin
Albumin can also be lost in case of major burns with important continuity of the skin.
Other rarer causes of hypoalbuminemia are genetic abnormalities with alterations of the albumin synthesis system which therefore causes an insufficient production of albumin I have a production of normal levels of defective protein.
Low albumin symptoms
The main symptoms of low albumin are:
- declining edema (swelling in the legs)
- ascites (accumulation of fluid in the abdomen)
- pleural and pericardial effusion
- cutaneous jaundice (yellow skin)
- frequent hematomas and impaired coagulation function
- asthenia (ease of fatigue, weakness)
- eye swelling (eyelid and periorbital edema)
There are many others symptoms of hypoalbuminemia, linked to the specific pathologies that caused the decrease of albumin in the blood.
Low albumin consequences
What are the consequences of hypoalbuminemia?
Low albumin leads a greater exit of liquids from the vascular lumen, with accumulation in the peripheral tissues, with the development of edema. The accumulation of fluids usually starts from the lower limbs (declining edema) starting from the ankles, feet and pretibial region. Often, especially in patients with liver cirrhosis, fluids also accumulate in the peritoneal or abdominal cavity (ascites), at the level of the pleural calities (pleural effusion), and, not infrequently, at the level of the testicles.
The reduction of albumin levels will also lead to an alteration of circulating hormones, to a lower detoxification of the blood from toxins and oxygen free radicals and to a lower pH compensation in the blood.
Low albumin remedies
What is the cure for low albumin? Are there any therapies that can raise albumin levels?
After the finding of hypoalbuminemia, first you need to understand the reason for the reduction in albumin levels.
In the case of a food problem, you can consult a nutritionist and implement a diet with the adequate amount of protein, necessary to restore normal albumin. s undoubtedly, meat, cheeses, vegetable proteins contained for example in legumes (beans, soybeans, lentils, etc.). protein supplements which provide a high amount of albumin and protein without taking away the appetite.
In the event that low albumin is the result of a liver or kidney problem, we will try to implement the most appropriate therapy: antiviral therapy in case of chronic liver disease secondary to hepatitis B or hepatitis C, abstention from alcohol in the presence of alcoholic liver disease.
Administration of albumin for intravenously it is necessary in some situations, such as the presence of refractory ascites (i.e. accumulation of fluid in the abdomen, which cannot be eliminated with diuretic drugs alone), or after a paracentesis, that is, after the removal of the fluid accumulated in the abdomen using a special needle.Tags: Liver Laboratory medicine Proteins