Naturally occurring antibodies as therapeutics for neurologic disease: can human monoclonal IgMs replace the limited resource IVIG?

Development and analysis of semi-interpenetrating polymer networks for brain injection in neurodegenerative disorders

PURPOSE

Our aim was to assess the use of injectable, biocompatible and resorbable, hydrogel-based tools for innovative therapies against brain-related neurodegenerative disorders like Alzheimer's (AD) and Parkinson's (PD) diseases.

METHODS

Two compositions of semi-interpenetrating polymer networks (semi-IPNs) based on collagen and poly(ethylene glycol) (PEG) were investigated. We examined their viscoelastic properties, flow behavior, functional injectability, as well as in vitro biocompatibility with SH-SY5Y human neuroblastoma cells and murine primary neurons. We also evaluated the in vivo biological performance after subcutaneous and brain injection in mice.

RESULTS

selected semi-IPNs showed a gel-like behavior and were injectable through a 30 G needle, with the maximum load ranging from 3.0 to 3.9 N. In vitro results showed that immortalized cells kept their proliferative potential and neurons maintained their viability after embedding in both materials, with better performances for the gel with the higher collagen content. For both semi-IPNs, after subcutaneous injection, the inflammatory response was negligible; after brain injection, the tissue did not show any signs of damage or degeneration.

CONCLUSIONS

The results suggest that the selected semi-IPNs not only represent a proper environment for cells, but also, once injected in vivo, do not induce damage/inflammation in the surrounding brain tissue. These findings represent a crucial starting point for the development of minimally invasive and injectable hydrogel-based tools for innovative drug/cell-based therapeutic strategies against AD, PD, or other severe brain-related neurodegenerative pathologies.</p>

Protective autoantibodies in the rheumatic diseases: lessons for therapy

The adaptive immune system augments host defenses against diverse infectious threats, yet also carries intertwined risks for the development of autoimmune disease. The immune system incorporates homeostatic pathways for essential housekeeping functions that involve recognition of oxidation-modified endogenous molecules. Now, the properties of a physiological class of natural autoantibodies, which seem to modulate the severity or even prevent the onset of autoimmune disease, are beginning to be defined. Whereas disease-associated IgG autoantibodies to nuclear antigens and citrulline-modified self-proteins have been shown to activate innate pattern recognition receptors leading to increased cell death and tissue injury, a class of IgM autoantibodies to oxidation-associated neo-antigens can oppose these pathogenic effects. These naturally arising regulatory IgM autoantibodies enhance the capacity for the phagocytic clearance of host cells affected by programmed death pathways. These antibodies can also suppress key signalling pathways in the innate immune system involved in the control and resolution of inflammatory responses to Toll-like receptor agonists and disease-associated IgG autoantibodies.