- Kidney stones are one of the most common disorders of the
- Most kidney stones are calcium stones in the form of calcium
- Efficacy of hydroxycitrate (HCA) and citrate (CA) in inhibiting
the growth of calcium oxalate crystals studied
- HCA has the potential to cut the incidence rate of people with
chronic kidney stone disease
Hydroxycitrate (HCA), a natural fruit extract was found to be capable of dissolving calcium oxalate crystals, the most common component of human kidney stones
. This key finding could lead to the first advance in calcium oxalate treatment.
What are Kidney Stones?
Kidney stones are formed when the substances in the urine (calcium, oxalate and phosphorus) become highly concentrated. Common symptoms of kidney stones include severe pain in the side and the back, pain on urination and pink color
urine. Hypertension, diabetes and overweight can increase the risk of kidney stones
. Over the last three decades there is not much change in the preventive treatment.
‘Hydroxycitrate (HCA) a citric acid derivative has the potential to be an effective inhibitor of kidney stone formation.’
In the United States more than 300,000
people go to emergency rooms for kidney stone problems.
Types of Kidney Stones
- Calcium Stones - Most common type
of kidney stone
- Uric Acid Stones are formed when
the urine is acidic
- Struvite Stones usually result from
- Cystine Stones arise from a genetic
disorder that causes cystine to leak through the kidneys and into the
Doctors often recommend citrate (CA) supplement in the form of potassium citrate
to slow the oxalate crystal growth but some people are unable to tolerate the side effects of the drug.
research study grew out of preliminary work done by collaborator John Asplin, a
nephrologist at Litholink Corporation, who suggested HCA could be a possible
treatment for treating kidney stones.
HCA or CA for Treating Kidney Stones
- The chemical structure of HCA and CA is similar
- HCA and CA are available in the form of dietary supplement
compared the efficacy of CA and HCA in inhibiting the growth of calcium oxalate
crystals and found that HCA was more potent and advantageous when compared to
CA. Researchers used atomic force microscopy (AFM) technique to study the
interactions between the crystals CA and HCA under realistic growth conditions.
Force Microscopy (AFM) Study Findings
generated by AFM recorded the shrinking of the crystal when exposed to specific
HCA concentrations, reported Chung. Rimer suspected that Chung's initial
finding was an abnormality, as it is a rare condition to see a crystal dissolve
in a supersaturated growth solution. But later it was turned out that Chung's
initial finding was correct. Scientists later carried out research work to
figure out the reasons behind the shrinkage of the crystal in a supersaturated
and CA Bind to the Calcium Oxalate Crystals?
and Taylor used density functional theory (DFT) a computational method to study
the structure and the properties of the materials. HCA formed a stronger bond
with the calcium oxalate crystal surfaces, inducing a strain that is relieved
by the release two molecules - calcium and oxalate, which aid in the crystal
Testing on Humans
of HCA was also tested in human subjects. Seven people took HCA in the form of
dietary supplement for three days. HCA was excreted through urine, a
requirement for a dietary supplement to work as a therapy.
said the research established the groundwork to design an effective drug,
questions remain. Long-term safety, dosage and additional human trials are
needed. "But our initial findings are very promising," he said.
"If it works in vivo, similar to our trials in the laboratory, HCA has the
potential to reduce the incidence rate of people with chronic kidney stone
Rimer, associate professor of chemical engineering at the University of Houston
is the lead author of the study published in the online edition of Nature.
In addition to Rimer and Asplin,
authors on the paper include Giannis Mpourmpakis and his graduate student,
Michael G. Taylor, of the University of Pittsburgh; Ignacio Granja of Litholink
Corporation, and Jihae Chung, a UH graduate student working in Rimer's lab.
- Drink lots of water
- Avoid foods rich in oxalate such as okra, spinach, almonds,
- Choose a low salt diet
- Eat more dairy foods
- Maintain a healthy weight
- Kidney Stone Prevention - (http://www.mayoclinic.org/diseases-conditions/kidney-stones/basics/prevention/con-20024829)
- Kidney Stones in Adults - (https:www.niddk.nih.gov/health-information/health-topics/urologic-disease/kidney-stones-in-adults/Pages/facts.aspx)