Parasites protect against type 1 diabetes

Pubblicato il

Monday, 4 March 2019

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Retina

Helminths, worm-like metazoan parasites, have been shown to have protective effects against type 1 diabetes mellitus (DMT1). Although it may sound strange that a class of parasites has beneficial effects on human health, this does not actually come as a great surprise to the scientific community. Indeed, man has always lived in close coexistence and in optimal balance with other living species, establishing a relationship of 'symbiosis' from which, in general, they both benefit. Helminths, in particular, have always lived in symbiosis with humans for millions of years, interacting and stimulating the immune system.

Today, however, due to radical changes in the hygienic and economic conditions of developing countries, the exposure of humans to helminths has inevitably decreased with consequent alterations in their symbiotic balance and alterations in the immune system of the host, humans in this case.

The hypothesis put forward by some researchers is that reduced exposure to these parasites has increased the frequency of the type 1 diabetesform of diabetes of autoimmune origin.

Epidemiological data

Epidemiological studies suggest that the rate of DMT1 has increased as the frequency of helminth infections has decreased. Confirming this, data from the World Health Organisation (WHO) report that The incidence of certain autoimmune diseases, such as TDM1, increases in populations originating in countries such as Africa or Asia when they migrate to industrialised countries.

These data suggest, therefore, that exposure to an animal-transmitted pathogen may be a preventive factor for TMD1.

What are the mechanisms of helminth-induced protection from DMT1?

Data, albeit preliminary, show that helminths have the ability to sequentially stimulate various immune responses, both innate and adaptive. For example, helminth infections, or simply their products, are powerful stimulators for certain cellssuch as Tregs, a cell lineage essential for the proper modulation of the immune system, as well as the increase of macrophages, cells highly specialised in the immune response.

Future implications of helminth studies

From the data currently available, it appears, therefore, that helminths and their products are able to stimulate the immune system by preventing the onset of DMT1. Therefore, scientists are interested in developing molecules derived from these parasites that have an immune-regulatory and protective effect against diabetic disease. Indeed, numerous studies are currently underway to identify the bioactivity of helminth-derived molecules with a view to developing new therapeutic agents.

Many concerns remain: first of all, it must be said that helminths can also be responsible for infections; secondly, the results in vivo may still take several years and all possible side effects should be evaluated.