Extracellular vesicles derived from mammalian cells could be useful carriers for drug delivery systems (DDSs); however, with regard to clinical application, there are several issues to be overcome. Acerola ( Malpighia emarginata DC.) is a popular health food. In this study, the feasibility of orally administered nucleic acid drug delivery by acerola exosome-like nanoparticles (AELNs) was examined. AELNs were recovered from acerola juice using an affinity column instead of ultracentrifugation. MicroRNA (miRNA) was sufficiently encapsulated in AELNs by 30-min incubation on ice and was protected against RNase, strong acid, and base treatments. The administration of an AELN/miRNA mixture in cells achieved downregulation of the miRNA’s target gene, and this mixture showed cytoplasmic localization. AELNs orally delivered small RNA to the digestive system in vivo . The target gene-suppressing effect in the small intestine and liver peaked 1 day after administration, indicating potential for use as an oral DDS for nucleic acid in the digestive system.

Transient neonatal hypothyroidism was found in a daughter of a 25-yr-old mother, who was receiving treatment for primary hypothyroidism due to Hashimoto's thyroiditis. During the neonatal period the infant had antithyroid microsomal and antithyroglobulin antibodies and TSH-receptor antibodies. The daughter recovered spontaneously from the hypothyroid state and the antithyroid antibodies disappeared from her serum. The mother's serum contained the same antibodies, and immunoglobulin G (IgG) from maternal serum blocked TSH binding to its receptors, TSH-stimulated cAMP responses, and cAMP-stimulated iodine uptake and organification in cultured thyroid cells. The latter finding suggests that the IgG had a postreceptor locus of action as well as inhibiting TSH binding to its receptor. The presence of such IgGs might have induced hypothyroidism both in the mother and in the daughter.

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