Human islet amyloid polypeptide (hIAPP) - a curse in type II diabetes mellitus: insights from structure and toxicity studies

The human islet amyloid polypeptide (hIAPP) or amylin, a neuroendocrine peptide hormone, is known to misfold and form amyloidogenic aggregates that have been observed in the pancreas of 90% subjects with Type 2 Diabetes Mellitus (T2DM). Under normal physiological conditions, hIAPP is co-stored and co-secreted with insulin; however, under chronic hyperglycemic conditions associated with T2DM, the overexpression of hIAPP occurs that has been associated with the formation of amyloid deposits; as well as the death and dysfunction of pancreatic β-islets in T2DM. Hitherto, various biophysical and structural studies have shown that during this process of aggregation, the peptide conformation changes from random structure to helix, then to β-sheet, subsequently to cross β-sheets, which finally form left-handed helical aggregates. The intermediates, formed during this process, have been shown to induce higher cytotoxicity in the β-cells by inducing cell membrane disruption, endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, islet inflammation, and DNA damage. As a result, several research groups have attempted to target both hIAPP aggregation phenomenon and the destabilization of preformed fibrils as a therapeutic intervention for T2DM management. In this review, we have summarized structural aspects of various forms of hIAPP viz. monomer, oligomers, proto-filaments, and fibrils of hIAPP. Subsequently, cellular toxicity caused by toxic conformations of hIAPP has been elaborated upon. Finally, the need for performing structural and toxicity studies in vivo to fill in the gap between the structural and cellular aspects has been discussed.

A study to evaluate the antimicrobial activity of feracrylum and its comparison with povidone-iodine

Feracrylum, a water-soluble polymer of polyacrylic acid is known for its hemostatic property. Present work is an effort to evaluate its minimum inhibitory concentration (MIC) and compare it with the MIC of povidone-iodine. Ten different species of pathogenic microorganisms were selected, strains of which were obtained from Haffkine Institute. The organisms were maintained under appropriate culture media. The MIC of Freracrylum was determined by using tube culture method where its activity was compared against a standard antimicrobial agent providone-iodine. The study parameters showed that Feracrylum exhibits antimicrobial activity against a wide variety of microorganisms and its efficacy is comparable to that of povidone-iodine.