Biological Effects Of Attapulgite

Our plain-English summary of Biological Effects Of Attapulgite, by J. Bignon, P. Sebastien, A. Gaudichet, et al (1980).

The study

• Authors: J. Bignon, P. Sebastien, A. Gaudichet, M.C. Jaurand
• Published: Biological Effects Of Mineral Fibres (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 30, Pp. 163-181 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002582. The article is still under copyright, so we describe it here rather than post it.

In plain English

This chapter reported preliminary data on attapulgite (also called palygorskite), a fibrous clay mineral. It also gave background on the mineral's structure, production and uses. The authors examined three drugs sold in France for gastrointestinal diseases using transmission electron microscopy. The drugs contained attapulgite fibres with a mean length of 0.9 µm and a mean diameter of 0.05 µm. One patient was 41 years old, had lung fibrosis, and had been exposed for three years during mining and processing of French attapulgite. Lung washing fluid from this patient contained 42,000 attapulgite fibres per ml. The authors wrote that this case suggested the mineral can induce a pulmonary fibrosis identical to asbestosis. A 60-year-old woman had taken 9 g/day of drug No. 1 for six months. Her urine contained attapulgite fibres at a concentration printed as 300,000 (the unit is cut off in the scanned text). In laboratory tests, Spanish attapulgite damaged human red blood cells more than UICC chrysotile A did. Drugs Nos 1 and 2 caused rabbit lung macrophages to release enzymes. The authors noted that no epidemiological data were available. They concluded that the cytotoxic effects raise the possibility of a carcinogenic effect in the body.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Preliminary report combining mineral characterization, electron microscopy of drugs, two patient case observations, and laboratory (in vitro) tests on red blood cells and rabbit alveolar macrophages
• Who was studied: Three attapulgite-containing drugs sold in France; a 41-year-old patient with lung fibrosis exposed while mining and processing French attapulgite (1973-1975); a 60-year-old woman who took drug No. 1; human red blood cells; rabbit alveolar macrophages
• Exposure: Attapulgite (palygorskite): activated Mormoiron (French) attapulgite in three drugs, Spanish attapulgite, and attapulgite dust from mining and processing. Comparisons were made with UICC chrysotile A, acid-treated chrysotile and quartz.
• Main results:
  • Attapulgite fibres found in the French drugs had a mean length of 0.9 µm (range 0.1 to 3.6) and a mean diameter of 0.05 µm
  • Case 1: lung washing fluid from the 41-year-old patient with lung fibrosis contained attapulgite fibres at 42,000/ml. The authors stated that the case suggests attapulgite can induce a pulmonary fibrosis identical to asbestosis.
  • Case 1 (continued): the authors' statement that the case suggests a pulmonary fibrosis identical to asbestosis
  • Case 2: urine of a 60-year-old woman treated for six months with 9 g/day of drug No. 1 contained attapulgite fibres at a concentration of 300,000 (unit cut off in text). The authors stated this shows passage of fibres through the human gastrointestinal mucosa.
  • Spanish attapulgite was more haemolytic than UICC chrysotile A. Initial velocity of haemolysis was 300 and 150 %/min for attapulgite, versus 135 and 22 %/min for chrysotile, at 0.5 and 0.05 mg/ml respectively.
  • Initial haemolysis velocities as printed in Table 5 for attapulgite (300 and 150 %/min)
  • The haemolytic activities of the three drug samples were greater than or similar to that of UICC chrysotile
  • Drugs Nos 1 and 2 induced release of lactate dehydrogenase and beta-galactosidase from rabbit alveolar macrophages. Lactate dehydrogenase release was 45.5% for drug No. 1 and 39% for drug No. 2. The authors described this cytotoxicity as similar to that of acid-treated chrysotile and quartz.
• The authors' conclusion: The authors concluded that the cytotoxic effects seen in vitro with attapulgite fibres raise the possibility of a carcinogenic effect in vivo. They called for extensive epidemiological surveys to evaluate possible fibrotic and carcinogenic hazards to humans.
• Limitations the authors state:
  • No epidemiological data were available on people exposed to attapulgite by inhalation or ingestion
  • More research was needed on penetration, translocation and clearance of the fibres in animals and humans

Topics

Medical terms in this study, explained in our Lexicon: Palygorskite (Attapulgite), Transmission Electron Microscopy (TEM), Fibrosis, Pulmonary Fibrosis, UICC, Chrysotile, Macrophage, Carcinogenic.

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