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Experts discover new mechanism that accelerates polycystic kidney disease: Know all about it

Experts discover new mechanism that accelerates polycystic kidney disease: Know all about it
Kidneys act as filters for the blood © Shutterstock

Polycystic kidney disease can be painful and cause severe complications. Now a new study has uncovered a previously unrecognised mechanism that may accelerate this condition.

Written by Jahnavi Sarma |Updated : August 27, 2019 9:27 PM IST

Polycystic kidney disease is a painful disorder. In this condition, clusters of non-cancerous fluid-filled sacs, called cysts, form in the kidneys. A person suffering from this condition experience body aches and pains, abdominal bloating, kidney stones and high blood pressure. If left untreated, it can lead to cysts in the liver and vascular problems, including strokes. It may also cause kidney failure. Severe cases may require dialysis or a kidney transplant. There is no cure, as yet, for this condition. Physicians usually treat symptoms and the many complications that it may cause.

Now researchers from the University of California - Santa Barbara, have uncovered a previously unrecognised mechanism that may accelerate polycystic kidney disease. Thought to be a response meant to protect the kidneys, the rapid dilation of the tubules that conduct waste away from the kidneys in the form of urine has been found to be a trigger that causes rapid cyst growth in those with the autosomal dominant form of polycystic kidney disease. This affects around 500 out of 1000 Americans, say researchers.

The Journal of Clinical Investigation published this research.

UNCHECKED ACCUMULATION OF CRYSTALS CAN LEAD TO KIDNEY STONES

The kidneys filter the blood flowing through your body. Blood enters the nephrons. Here waste and fluid pass through the renal tubules, while cells and proteins stay in the blood. Some fluid and nutrients get reabsorbed into circulation. Excess fluid and waste become urine that flows to the bladder. Your kidney contains about a million such tubules, say researchers.

During this entire process, waste products like calcium oxalate, calcium phosphate and uric acid concentrate and form into crystals in the renal tubules. Most of the time, the body expels these microscopic crystals along with urine. But if the formation and accumulation of these crystals are not treated on time, it may lead to kidney stones.

Researchers say that the renal tubules dilate rapidly to flush out these crystals and then return to normal once the crystals are expelled. This dilation is a mechanism that was not previously recognised, they say.

The study says that in normal kidneys, the tubule dilation is a protective mechanism. The deposition of oxalate crystals triggers the rapid activation of protein signalling pathways that regulate cell growth and proliferation. This is accompanied by rapid dilation of the entire tubule system to dislodge the microcrystals. In kidneys genetically preconditioned to form these cysts, researchers found that these crystals can trigger the same dilation. But instead of going back to normal, those tubules overshoot and form cysts.

CONSTANT TUBULE DILATION CAUSES CYST FORMATION: EXPERTS

In individuals with polycystic kidney disease, the rapid and constant tubule dilation is seen as a 'third hit' physical injury that results in cyst formation. According to the 'third hit' model of cystogenesis, three events must occur to form individual cysts: The first two are genetic mutations and the third is a physiological damage/repair response. This results in an overcompensation by the renal tubule that leads to the formation of the fluid-filled sacs. The microcrystals could present a persistent and relevant type of injury in patients that could trigger the damage/repair response. They concluded that more crystals lead to the progression of this disease. In fact, it may be possible that the progression of this disease and kidney stone formation reinforce each other.

COMPLICATIONS OF POLYCYSTIC KIDNEY DISEASE

You may have polycystic kidney disease for years and be completely oblivious to the problem. This is dangerous because, if left untreated, it can cause serious complications.

Polycystic kidney disease can affect the other organs of the body. The clusters of fluid-filled sacs can interfere with the kidney's ability to filter waste products from the blood. It can lead to enlarged kidneys and may also cause kidney failure. Cysts may also appear in other organs like the liver.

Polycystic kidney disease patients often suffer from hypertension, kidney stones, pain in the back or sides, recurrent urinary tract infections, blood in urine and heart valve abnormalities. They may also suffer from an aneurysm in the aorta or in blood vessels at the base of the brain. If these aneurysms rupture, it may lead to life-threatening conditions.

Let us look at a few complications of polycystic kidney disease.

High blood pressure

This is a very common complication of polycystic kidney disease. It can further damage your kidneys and increase your risk of heart disease and stroke.

Kidney failure

This is a serious and dangerous complication of his disorder. Polycystic kidney disease interferes with the ability of your kidneys to flush out toxins. This is dangerous and you may require a dialysis or transplant to prevent toxicity and death.

Preeclampsia

Polycystic kidney disease may induce preeclampsia, a life-threatening condition, in pregnant women.

Liver cysts

Women are more at risk from this complication. But men may get liver cysts too. Experts say that this could be due to the influence of oestrogen hormone.

Brain aneurysm

This is basically a bulge in blood vessel. If it ruptures, it can be life-threatening. If you suffer from polycystic kidney disease, you have a higher risk of this complication.

Heart problem

A person with this disease may develop heart valve abnormalities. It can cause mitral valve prolapse. In this condition, the valve does not close properly. This causes a backward flow of blood.