DTPA chelation in individuals with joint replacements, other metal implants, and particle disease. My theories.

This is an edited/ expanded version of a recent email response I made to a colleague who asked me about a patient with a cranial vessel stent. I expand it to look at metals in general, and touch on MRI.

There is a condition  called  particle disease that refers to peri-prosthesis complications which are believed to be the result of inflammatory changes to released metal atoms in surrounding soft tissues, from the prosthesis. I have posted an earlier blog on this entity - I did not like the name then, and I don't like it now. A simple change would be Metal particle disease. Regarding chelation in individuals with prostheses: on the one hand, some are concerned that DTPA will attack the prosthesis itself, others however believe if anything the chelator may pick up loose peri-prosthesis atom ions. I am in this latter camp.

A lot of this has to do with relative strength of the chemical bonds involved. Metallic bonds are actually a separate type of bond, than covalent or ionic. Metals don't really bond with each other in the classic sense but layer with each other: metallic bond. So DTPA with ionic bonding capacity breaking metallic bonds in the prosthesis itself? I strongly doubt the ionic bond strength of DTPA is stronger than the metallic bond strength in the prosthesis itself. DTPA would really only have exposure to the surface of the prosthesis, since there are no blood vessels in the prosthesis to give DTPA access. In distinction, free  metal ions in surrounding soft tissue will be most likely in ionic bonded relationships with host polypeptides. So if anything the ionic bonding strength of DTPA to the released 'free' metal is likely stronger than the host tissue polypeptide bonding strength to the released metal, hence DTPA would remove these loose particles, and patient clinical condition improve.

The treatment for Metal Particle Disease would be with chelation. But the chelator with the highest log stability constant with the metal in question should be used. This may not be DTPA, or any currently available chelators.

I think an important future step is to develop more chelators with specific high log stability constant to various metals, which are either environment contaminants, or medical (or violence related, eg: bullets) implants. I would like to see a chelator with high bonding strength to Chromium (a nod to Erin Brockovich) and to titanium and platinum (from medical uses).

I have no problem then using DTPA chelation in individuals with joint prostheses. It may actually help them, by dealing with Particle disease.

Although I don't think it injures stents, of all organs I am least willing to test my theory in the brain. I would probably not chelate patients with small stents in intracranial vessels. This is because the brain does not heal with scarring, it heals with gliosis (essentially tissue disintegration). Different than intravascular stents, which has the vessel wall holding it in place, with brain vessel clips there really is nothing around it holding them in place. So intracranial clips are a no go, stents are more gray - but still I would see if general supportive and detox methods help. Clips in other tissues/ organs than brain, scarring in place does occur with them. So clips in a non-brain location, I would chelate patients with these. For cardiac clips I would wait 6 months for sufficient scarring to develop.

Note the concerns are present for MRI itself with metal, but the explanations are different.. With the MRI itself the concern is pulling off clips that contain iron. Clips that contain no iron like titanium, are not a problem. The concern with DTPA or other chelator is the erosion of the metal implant causing it to fail, regardless of the type of metal. As I said, in my opinion most metal implants are not contraindicated with chelation. Nuance and knowledge however are important to exercise.

Richard Semelka, MD