In the mid-Nineties, in a couple of different circumstances, we had the opportunity of analysing two caval filters broken in vivo (caval filters are metal devices implanted in the lumen of the inferior vena cava to prevent pulmonary embolism). On their surface, we found traces of metals, which did not belong either to the filter or to the human organism. No explanation could then be given to the finding. At the end of 1998, a patient was referred to the Policlinico of Modena from a hospital located in another town. The problem to be solved was that of an intermittent fever resistant to any treatment, which had had its onset more than eight years earlier.The diagnosis issued by the physicians in Modena was of a liver and kidney granulomatosis about whose origin nothing could be said.

For a number of coincidences, some of the bioptic samples relative to the case reached our Laboratory of Biomaterials and were examined with a method we were then experimenting, which employed an environmental scanning electron microscope equipped with an x-ray microprobe. Through that we could analyse, though with some limitations, the chemical elemental composition of the sample.Much to the surprise of the physicians, it was immediately evident that the tissues checked contained inorganic particulate matter whose composition was ascribable to a ceramic compound whose elements do not belong, either singly or in any bound form, to the human organism. On top of it, none of such compounds is biodegradable. As it turned out, the patient was the carrier of a dental prosthesis whose chemical composition was the same as that of the particles we had found, and that prosthesis showed very visible evidence of an abnormal wear caused by a malocclusion. It must be added that the prosthesis had been implanted just a few months before the symptoms arose. With these data, it was only reasonable to suppose that the patient had eaten away part of his prosthesis and swallowed inorganic matter for years.

Then that matter had reached his liver and his kidneys. How, we had no elements to say.More than that, namely if the particles had caused the granulomatosis or had been somehow captured by an already pathologic tissue, was then impossible to establish. If the problems were caused by the continuous ingestion of ceramic debris, no known therapy existed, and the only possibility was to get rid of the source. As a matter of fact, once the prosthesis was removed, the patient improved visibly, and his hepatomegaly receded along with the problems with his renal function. In the meantime, on the spur of such an unusual finding, we had started to check biopsies coming from patients suffering from some cryptogenic disease, that is to say pathologies to which today‚s medical science is unable to attribute an origin. The first step was to look for other cases of cryptogenic granulomatoses kept in the archives of the University of Modena and in those of Royal Free Hospital of London and the University of Mainz with which we had established collaboration. The results of that investigations were that in all the cases we had the possibility to check, inorganic particulates were present, and those materials had no chance of being of biological origin, as the elements they were composed of do not belong to any form of life. The consequence was that they must have come from outside, through the natural „doors‰ of the human body, namely the respiratory and digestive systems.

SEM image of colon cancer.
Red blood cells are close to aluminum-silicate debris.

There is currently increased concern for the possible detrimental effects of environmentally-derived foreign materials and particles on human health (see the hystory). For a long time air pollution has been recognised as one of the most important causative agents of lung disease. The question now arises whether foreign materials can cause pathological sequelae also by entering the body through the digestive tract. This project aims to investigate the presence and significance of very small particles of nanometer size in various diseases of unknown origin.