Assessment of Asbestos Burden in the Placenta and Tissue Digests of Stillborn Infants in South Texas

Abstract

The primary aim of this prospective study was to examine the tissues and placentas of autopsied stillborn infants for presence of asbestos fibers. Asbestos burden of lung, liver, skeletal muscle, and placenta digests of 82 stillborn infants was determined using standard bleach digestion technique. The digests were examined by electron microscopy, and the types of fibers determined using energy dispersive x-ray analysis and selected area diffraction analysis. Digests of 45 placentas collected from deliveries of liveborn healthy infants were processed and examined similarly as controls. Asbestos fibers were detected in 50% of the fetal digests and 23% of the placental digests of stillborn infants. Of the fibers present, 88% were chrysotile, 10% were tremolite, and 2% were actinolite and anthophyllite. Fibers measured 0.5-16.73 microgram in length (mean 1.55 microgram), and 0.03-0.8 microgram in width (mean 0.098 microgram). Lungs were most frequently positive for fibers (50%), followed by muscle (37%), placenta (23%), and liver (23%). Mean fiber counts were highest in the liver (58,736 f/g), followed by placenta (52,894 f/g), lungs (39,341 f/g), and skeletal muscle (31,733 f/g). Digests of 15% of the control placentas also showed asbestos fibers, although in very small numbers. The mean fiber count of the stillborn placentas (52,894 f/g) was significantly higher than the mean fiber count of the control placentas (mean 19 f/g) (p = 0.001). A highly significant association was found between fiber presence in stillborns and a maternal history of previous abortions (p = 0.007). A significant association was also found between fiber presence and placental diseases (p = 0.041). An association was suggested between working mothers and fiber presence (p = 0.19), although it did not reach statistical significance. The study documents the presence of small and thin asbestos fibers in stillborn fetal tissues and placenta. Significantly higher number of fibers were found in stillborn tissues compared to controls (liveborn placenta). The absence of a maternal history of asbestos-related occupations suggests that the fibers may have been acquired through environmental exposure.

Amphiboles: Environmental and Health Concerns

“…However, fi bers of amphibole asbestos have been found at high levels (both in the presence and absence of pathologies) in various other organs and tissues: in the visceral and parietal pleura (Tossavainen et al 1994), in the larynx (Griffi ts and Malony 2003), in ovaric and intratesticular mesothelium (Attanos and Gibbs 2000), in omentum and mesentery (Dodson et al 2000a), in lymph nodes (Dodson et al 2000b), in the urothelium and the bladder wall (Pollice et al 1995), in the intestinal mucosa (Storeygard et al 1977), in the kidneys (Holt 1981), in the placenta (Haque et al 1998), and in the liver and muscles of stillborn (Haque et al 1998). Amphibole asbestos has been found also in biological fl uids: in sputum (e.g., Putzu et al 2006) and in bronchoalveolar lavage fl uid -BALF (e.g., Sartorelli et al 2001).…”

Asbestos Exposure and Gestational Trophoblastic Disease: A Hypothesis

“…Haque et al found that the number of fibers present in the stillborn placenta were similar to the number present in the stillborn fetal tissue and that placental and fetal liver digests had higher fiber burdens than fetal lung and muscle digests, suggesting that the fibers were blood-borne. This suggests that transplacental transfer of fibers occurs via the maternal circulation (15). In support of this theory, chrysotile (white asbestos) fibers have been observed in newborn mice following gavage feeding of their pregnant mothers, suggesting that the fibers can pass across the placental barrier (17,18).…”

“…A statistically significant association was found between the presence of fibers and placental diseases (odds ratio, 2.8; 95% confidence interval, 1.0-7.8; P = 0.041; ref. 15). Haque et al found that the number of fibers present in the stillborn placenta were similar to the number present in the stillborn fetal tissue and that placental and fetal liver digests had higher fiber burdens than fetal lung and muscle digests, suggesting that the fibers were blood-borne.…”

Revision of French Occupational Exposure Limits of Asbestos and Recommendation of Measurement Method: Can the Dimensional Characteristics of the Asbestos Fibers (Long, Thin, Short) Be Taken Into Account?

“…In humans, asbestos fibers have been particularly identified in samples of lymphatic ganglions (Dodson et al, 1990;Sebastien et al, 1979), in healthy or diseased parietal pleura (Boutin et al, 1996;Dodson et al, 1990;LeBouffant et al, 1976;Sebastien et al, 1980;Suzuki and Kohyama, 1991;Suzuki et al, 2005), omentum and radix mesenteri (Dodson et al, 2001;Dodson et al, 2000) and in the placenta and tissue samples of stillborn infants (Haque et al, 1996;Haque et al, 1992;Haque et al, 1998).…”