- Osteoporosis is a condition which causes the bone to become weak and brittle.
- Bisphosphonate drugs used in the treatment of osteoporosis is linked to an increased risk of 'micro-cracks' in the bone.
Osteoporosis is a condition that causes thinning of bones. A recent research from the scientists at Imperial College London found a type of drug called Bisphosphonates used in the treatment of osteoporosis to be associated with an increased risk of 'micro-cracks' in the bone.
They also found that micro-cracks are capable of reducing the mechanical strength of the bone.
‘Osteoporotic Bisphosphonate drugs are found to increase the risk of micro-cracks in the bone.’
The research study was published in the journal Scientific Reports.
Bisphosphonate Drugs Increase Micro-cracks in bone
The research study found bone samples obtained from 16 people who had been diagnosed with a weak bone condition osteoporosis. These patients had suffered a broken hip and half of them were found to take a type of commonly-prescribed drug called bisphosphonate.
The research team used X-Rays from the Diamond synchrotron to visualize the structure of the bone at a high resolution.
They also found that the bones of people who took drugs not only had large number of tiny cracks but even had less mechanical strength.
Dr. Richard Abel, the lead author of the study research, Department of Surgery and Cancer at Imperial, said, "Although this is a very small, early-stage study, the results are quite startling, and justify follow-up studies."
"These microcracks are like the small cracks that emerge when you repeatedly flex a plastic ruler - they gradually weaken the structure and may potentially make it more prone to breaking."
Around 6.5 million prescriptions with bisphosphonate drugs in the UK and around 190 million in the world were found to prevent the risk of fracture by 30-50%.
However, doctors now feel that the use of bisphosphonate drugs may increase the risk of fracture.
Osteoclasts cells are present in the bone for a breakdown. These cells are needed to remove the damaged bone and replace with the new bone.
Using bisphosphonate drugs may make the osteoclast cells too sluggish and may leave them more prone to damage.
The research team analyzed the cracks and perforations in the microstructure of bone. A standard X-ray equipment in labs or hospitals involves a conventional way were bone thinning is detected.
They also used a particle accelerator which involves the diamond light source in Oxford to analyze the bone samples.
Eight hip bone samples from patients who suffered fracture while taking bisphosphonates and eight samples from patients who suffered a fracture and had not been taking the medication were studied.
The samples were collected from the patients during hip replacement procedures, and the patients were between 60 - 90 years old.
The research team also studied hip bone samples from patients who do not have osteoporosis and have not experienced hip fracture. They also tested the mechanical strength of the bone samples.
The findings of the study found that bones of the people who took bisphosphonates may have 24% more microcracks than people who did not take any medications and 54% more than healthy aging people.
The bones from patients treated with bisphosphonates were 33% weaker when compared to those who did not take the medication.
The research team also used mathematical models to confirm the difference.
Dr Abel explained, that "This research suggests that, in a small number of patients, rather than protecting against fractures bisphosphonates may actually may make bones more fragile. We now urgently need larger studies to confirm this finding."
Further studies were required to provide insight on whether there is an ideal length of time that prescribed the drugs.
"There may be a crucial time point between holes in the bone being prevented, and microcracks beginning to form. If we can find this, we may be able to ensure bisphosphonates provide maximum protection against fractures by personalising the duration of treatment."
"Long term we may need to develop other therapies that treat osteoporosis by building new bone rather than slowing the breakdown of old bone".
The author also concluded that the research team will further investigate on whether the microcracks are formed on patients who take bisphosphonates and not sustained fractures.
Osteoporosis may cause the bones to weaken and result in breaks. It is a condition where the breakdown of bone may outpace rebuilding. Around 3 million people in the UK and 200 million people in the world are affected with osteoporosis. The condition is found to affect people over the age of 65.
The weakening of the bones may cause common fractures in the hip, wrist and spine.
Bisphosphonate drugs are used for slowing down or preventing bone damage. These drugs also lower calcium levels. Drugs like Disodium pamidronate, Ibandronic acid, Sodium clodronate, Zoledronic acid are bisphosphonates.
The drugs act by slowing down the rate at which the bone is broken down. They reduce the activity of osteoclasts (Cells that break down bone).
The drugs are prescribed to
- Lower the risk of bone breakdown
- Prevent or control the thinning of the bones (osteoporosis)
What bisphosphonates are - (http://www.cancerresearchuk.org/about-cancer/cancers-in-general/treatment/bisphosphonate/what-bisphosphonates-are)