Normally, urine contains a certain amount of protein less than 150mg/24h.
Besides
Kidney Diseases, many factors can increase protein in urine, such as
strenuous sports, the food of high protein and a fever. However, the increasing
protein in urine is related to kidneys.
Renal tissues related to protein in urine How Do Kidney Disease Patients Know They Have Protein in Urine
Kidneys are able to filtrate metabolic waste out to form the urine and
prevent the nutrients escaping from blood flow at the same time. Their renal
functions are attributed to unique tissues and structures, especially renal
intrinsic cells including glomerular endothelial cells, glomerular epithelial
cells, epithelial cells of renal tubules, mesangial cells and renal ibroblasts.
With mechanical barrier and charge barrier, glomerular epithelial cells play the
main role in preventing protein from blood.How Much Protein Should a Person with Renal Disease Eat
Protein and glomerular epithelial cells both carry negative charges. As same
charges repel each other, protein can not pass though the hiatuses of glomerular
epithelial cells.How Can IgA Nephropathy Patients Avoid Losing Protein
Besides mechanical barrier, there are many foot processes among glomerular
epithelial cells, which can prevent some macromolecular protein releasing from
blood flow.
Abnormal structure causing Protein in urine Stop Protein Leakage in Nephrotic Syndrome Without Steroids
When people are infected, immune system will react against virus and bacteria
invading. Immune complex are produced from the combination of antibody and
antigen. Those immune complexes will reach and deposit in kidney along with
blood circulation. The deposition of those immune complexes can damage renal
intrinsic cells especially glomerular epithelial cells. Negative charges
disappear and foot processes are effaced and run together. A lot of protein
escapes uninterruptedly into urine through glomerular epithelial cells. This
kind of urine is called proteinuria.
Less protein decreases plasma osmotic pressure but pressure increases in
Portal vein, which keep more fluid in tissues and cause edema or swellings. In
late stage, other cells are damaged and the normal renal tissues are covered by
the extracellular matrix, kidneys fail in draining out excess water and sodium
which also worsens edema.