More than half a million Americans every year visit the emergency room for problems related to kidney stones. In most cases, the stones eventually pass out of the body on their own, but the process can be excruciatingly painful.
Researchers at MIT and Massachusetts General Hospital have 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 directly to the ureter with a catheter-like instrument.
Relaxing the ureter could help stones move through the tube more easily, the researchers say.
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 is passed, to prevent the tube from becoming blocked or collapsing.
How Does One Get Kidney Stones
Kidney stones are 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 is estimated that about one in 10 people will have a kidney stone at some point in their lives.
While some larger stones require surgery, the usual treatment plan is simply 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 is meant to help relax the ureter, but studies have offered conflicting evidence on whether this drug actually helps.
“If you look at how kidney stones are treated today, it hasn’t really changed since about 1980, and there’s a pretty substantial amount of evidence that the drugs given don’t work very well,” Lee says. “The volume of how many people this could potentially help is really exciting.”
The researchers first set out to identify drugs that might work well when delivered directly 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. They hypothesized that if they delivered such drugs directly to the ureter, they could get a much bigger relaxation effect than by delivering such drugs orally, while minimizing possible harm to the rest of the body.
“We found several drugs that had the effect that we expected, and in every case we found that the concentrations required to be effective were more than would be safe if given systemically,” Cima says.
Next, the researchers used intensive computational processing to individually analyze the relaxation responses of nearly 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 is used to treat glaucoma.
The researchers tested various doses of this combination of drugs in ureters removed from pigs, and showed that they could dramatically reduce the frequency and length of contractions of the ureter. Tests in live pigs also showed that the treatment nearly eliminated ureteral contractions.
For these experiments, the researchers delivered the drugs using a cystoscope, which is very similar to 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.
If you think you might be suffering from kidney stones, then you probably need a quality urologist. Pick up the phone and call Z Urology, with offices in South Florida. Call today!
We provide state-of-the-art urologic care in the South Florida area with a focus on both male and female urology. Our practice specializes in all urologic procedures, specifically, minimally invasive methods. Our three locations to choose from are located in Fort Lauderdale, Coral Springs and Pompano Beach.
We at “Z” specialize in bladder issues, erectile dysfunction (ED), prostate issues, urinary incontinence, sexual dysfunction, stone disease, BPH, male infertility, pyeloplasty, Peyronie’s disease, and ureteral reimplantation.