Studies on the potential risk of amyloidosis from exposure to silk fibroin

Abstract

Amyloid A (AA) amyloidosis can be induced by the administration of amyloid fibrils to animals under inflammatory conditions. Silk fibroin (SF) is a main component protein of bombic silk and has amyloid-like features. The amyloidogenesis of SF solution in mice has been previously reported. Recently, the biochemical properties of silk have attracted increasing attention, and research and development have been undertaken regarding applications other than as a clothing material. However, the risk of AA amyloidosis from exposure to SF-related products is unknown. In this study, we examined the amyloidogenesis of several SF-related products that vary in preparation method or route of injection in a mouse model of amyloidosis. The results revealed that amyloid deposits were rarely observed in mice exposed to SF solution or feed supplemented with SF powder. On the other hand, heavy amyloid deposits were observed in some mice implanted with SF non-woven fabric by abdominal operation. Congo red staining of SF solutions under polarized light and electron microscopy indicated that SF solution in this study had no amyloid-like structures. We found that SF-related products occasionally promote amyloidogenesis, but have a low potential for amyloidosis.

Silk fibroin safety in the eye: a review that highlights a concern

“…Currently, despite centuries of use, there appears to be little evidence that human amyloidosis has been caused by silk, but conversely there has also been insufficient specific long-term investigation. A low potential for amyloidosis 72 needs to be risk-assessed with long-term studies for specific sites involving simultaneous inflammation. 69 First, to do no harm, remains a basic tenet of medical treatment and potential harm needs to be fully assessed before fibroin is used as a biomaterial in the eye.…”

“…Fibroin has also been shown to be a relatively poor seed in Aβ40 and Aβ42 aggregation. 49 A direct study of the risk of fibroin for amyloidosis by Tsukawak et al, 72 concluded that silk occasionally promotes amyloidogenesis, but has a low potential for amyloidosis. Amyloid deposits were rarely observed in mice injected with silk fibroin in solution, but with certain methods of production, heavy amyloid deposit resulted from fibroin fabric placed in the abdomen; the production method is an important determinant of its biocompatibility.…”

Silk fibroin-based vascular repairing sheet with angiogenic-promoting activity of SVVYGLR peptide regenerated the damaged vascular in rats

“…This non-woven scaffold is considered to be effective for the migration, attachment, and infiltration of cells, which are suitable advantages for regenerative sheets. 10,22,24…”

“…Immunohistochemical staining was performed with the Envision+ kit (Dako, Carpinteria, CA, USA), using the following freshly prepared primary antibodies: monoclonal rabbit anti-CD34 antibody (ab81289, 1:100, Abcam, Cambridge, UK), polyclonal rabbit anti-alpha smooth muscle actin (alpha-SMA) antibody (ab5694, Abcam, Cambridge, UK), polyclonal rabbit anti-Iba1 antibody (013-27691, FUJIFILM Wako Pure Chemical Corporation, Japan), and rabbit anti-SF serum (1:80,000). 22…”

Removal of radioactive cesium from contaminated water by whey protein amyloids–carbon hybrid filters

“…The assessment of the adverse effects upon exposure (by ingestion or inhalation) to materials containing pathological amyloid brils is still under study. [36][37][38] At present, global safety guidelines and/or protocols for handling this type of material are not yet fully dened. However, there start to be converging opinions that the use of food-based amyloids, as in the present case, is safe for human consumption.…”