Nutrient-sensing amyloid metastasis

Dietary phytate induces subclinical mechanical allodynia in mice

Neuropathic pain is a condition with varying origins, including reduced dietary micronutrient intake. Phytate is a polyphosphate found in seeds and grains that can act as an antinutrient due to the ability of sequester essential divalent metals. Here we tested whether moderate dietary phytate intake could alter nociceptive pain. We subjected weaning mice to a chow supplemented with 1% phytate for eight weeks. Body weight gain, glycemic responses, food ingestion, water ingestion, and liver and adipose tissue weights were not altered compared to controls. We observed a decreased mechanical allodynia threshold in the intervention group, although there were no changes in heat- or cold-induced pain. Animals consuming phytate showed reduced spinal cord tumor necrosis factor (TNF), indicating altered inflammatory process. These data provide evidence for a subclinical induction of mechanical allodynia that is independent of phytate consumption in animals with otherwise normal phenotypic pattern.

Formation of subvisible particles in commercial insulin formulations

The conformation and assembly of insulin are sensitive to physical and chemical variables. Insulin can misfold and form both amorphous and amyloid aggregates. Localized cutaneous amyloidosis due to insulin usage has been reported, and question remains regarding its stability in the original flasks due to storage and handling. Here we report the evaluation of the formation of aggregates in insulin formulations upon once-weekly handling and storage of the in-use cartridges at 4 °C or 37 °C for 5 weeks. Electrospray ionization mass spectrometry showed no obvious chemical decomposition. No major changes in oligomeric distribution were observed by size-exclusion chromatography. Dynamic light scattering allowed the identification of particles with high hydrodynamic radius formed during storage at 4 °C and 37 °C. Transmission electron microscopy analysis revealed the formation of amorphous material, with no clear evidence for amyloid material up to 28 days of incubation. These data support evidences for the formation of subvisible and submicrometer amorphous particulate matter in insulin formulations shortly upon use.