Every year, more than half a million americans visit the emergency room for kidney stone problems. In most cases, the stones pass out of the body on their own, but the process can be painful, Now researchers found the new treatment helps to cross kidney stone easily.
Researchers at MIT and Massachusetts General Hospital have now devised a potential treatment that could make passing kidney stones faster and less painful.
They have identified a combination of two drugs that relax the walls of the ureter the tube that connects the kidneys to the bladder and can be delivered to the ureter with a catheter-like instrument.
Relaxing the ureter could help stones move through the tube more, the researchers say.
This could impact kidney stone disease, which affects millions of people, the researcher said.
This kind of treatment could also make it easier and less painful to insert stents into the ureter, which is sometimes done after a kidney stone passed, to prevent the tube from becoming blocked or collapsing.
Kidney stones made from hard crystals that accumulate in the kidneys when there is too much solid waste in the urine and not enough liquid to wash it out. It estimated that about one in 10 people will have a kidney stone at some point in their lives.
While some larger stones must surgery, the usual treatment plan is to wait for the stones to pass, which takes an average of 10 days. Patients are given painkillers as well as an oral medication that meant to help relax the ureter, but studies have offered conflicting evidence on whether this drug helps.
Cima and Eisner thought that delivering a muscle relaxant to the ureter might offer a better alternative.
Most of the pain from passing a kidney stone arises from cramps and inflammation in the ureter as the stones pass through the narrow tube, so relaxing the muscles surrounding the tube could help ease this passage.
The researchers first set out to identify drugs that might work well when delivered to the ureter. They selected 18 drugs used to treat conditions such as high blood pressure or glaucoma and exposed them to human ureteral cells grown in a lab dish, where they could measure how much the drugs relaxed the smooth muscle cells.
Next, the researchers used intensive computational processing to analyze the relaxation responses of 1 billion cells after drug exposure.
They identified two drugs that worked especially well and found that they worked even better when given together. One of these is nifedipine, a calcium channel blocker used to treat high blood pressure, and the other is a type of drug known as a ROCK (rho kinase) inhibitor, which used to treat glaucoma.
The researchers tested various doses of this combination of drugs in ureters removed from pigs and showed that they could reduce the frequency and length of contractions of the ureter. Tests in live pigs also showed that the treatment eliminated ureteral contractions.
For these experiments, the researchers delivered the drugs using a cystoscope, which is very like a catheter but has a small fiber-optic channel that can connect to a camera or lens.
They found that with this type of delivery, the drugs were not detectable in the animals’ bloodstream, suggesting that the drugs remained in the lining of the ureter and did not go elsewhere in the body, which would lessen the risk of potential side effects.
More studies needed to determine how long the muscle relaxing effect lasts and how much relaxation would be needed to stone passage, the researchers say.
They are now launching a startup company, Fluidity Medicine, to continue developing the technology for possible testing in human patients.
Also to treating kidney stones, this approach could be useful for relaxing the ureter to help doctors insert a ureteral stent. It could also help when placing any other kind of instrument, such as an endoscope, in the ureter.
The platform pairs drug delivery to the ureter. We are eager to first target muscle relaxation, and as offshoots of that, we have kidney stones, ureteral stents, and endoscopic surgery.
The researcher said, We have a bunch of other urological indications that would go through different developmental pathways but can all hit and all have meaningful patient populations.