In vitro testing of highly diluted cytokines and specific nucleotide acid sequences applied in micro-immunotherapy for rheumatoid arthritis

Background: TNF-α and IL-6 are key inflammatory factors in rheumatoid arthritis (RA) and constitute targets for the development of anti-inflammatory drugs. Rather than apply antagonist strategies, the micro-immunotherapy approach is based on the use of very low doses and highly diluted cytokines and specific nucleotide acid sequences (SNA^®) which, administered sequentially, are intended to reduce synovial inflammation and to regulate auto-immune disorders associated with RA.

Objectives: the aim of these in vitro studies was double: i) assess on various cellular models the biological activities of serial homeopathic dilutions of cytokines and SNA developed for a new Micro-Immunotherapy medication (2L^®PR) and ii) investigate their mechanism of action by using biomolecular tools.

Methods: a first set of experiments was performed on human fibroblast-like synoviocytes (FLS) isolated from RA patients and cultured in standardized conditions. Different protocols of treatment were applied to examine the potential anti-inflammatory effect of major cytokines (IL-1, IL-2, IL-6, IL-10, IFN-γ, TNF-α) administered in a large range of dilutions (3CH to 27CH). Homeopathic solutions were tested alone or in association on FLS activated with various concentrations of TNF-α (0.1, 1 and 5 ng/ml). Preliminary tests were carried out on non-activated FLS. IL-6 release was determined in cell supernatants by ELISA. In addition, the anti-inflammatory effect of TNF-alpha 5CH formulated in homeopathic pellets was controlled on this FLS model. In a second set of experiments, high dilutions (HD) of SNA sequences designed to target the gene of two major proteins involved in RA (TNF-α and its receptor p55) were investigated on a LPS-stimulated macrophage (THP1) model. TNF-α synthesis and release were determined by RT-PCR (mRNA) and ELISA (protein), after stimulation by LPS (1μg/ml).

Results: in the first set of experiments, we observed that priming of cells with TNF-α and IL-6 dilutions down-regulated IL-6 release by TNF-α activated FLS. The same result was obtained with pellets of TNF-α 5CH. This effect was not obtained with other major cytokines such as IL-1, IL-Ra, IL-2, IL-10, and IFN-γ. In the second set of experiments, we demonstrated that HD of both SNA significantly down-regulated TNF-α synthesis and release. This biological activity was showed to be specific (no effect of HD scramble SNA) and related to the level of dilution (maximal effect with higher dilutions). Unexpectedly, a reproducible stimulation effect of HD water was obtained in the LPS-stimulated THP1 model. This biological activity of agitated water (negative control) was not detected in TNF-α activated FLS model.

Conclusions: these findings indicate that homeopathic dilutions of TNF-α and IL-6 can regulate IL-6 release by synoviocytes and that highly diluted SNA RA can regulate TNF-α synthesis and release by LPS-stimulated THP1. This exploratory work supports the hypothesis that micro-immunotherapy may represent an alternative therapeutic approach for RA and that high dilutions act in modulating mRNA expression of the targeted genes.

Keywords:

Specific Nucleic Acids (SNA®) - Cytokines - Micro-Immunotherapy - Cellular models - Rheumatoid arthritis

This project was supported by the Walloon Region (General Direction for Technologies, Research and Energy), Grant n°5899 and Labo'Life Belgium.