Parasitic helminths and their beneficial impact on type 1 and type 2 diabetes

Abstract

It is estimated that by the year 2035 almost 600 million people will suffer from diabetes. In the case of type 2 diabetes, the strongest increase of diabetes incidence occurs in developing and newly industrialized countries. This increase correlates not only with a progressing sedentary lifestyle and nutritional changes, but also environmental changes. Similarly, the increase of type 1 diabetes incidence in industrialized countries over the past decades cannot be explained by genetic factors alone, suggesting that environmental changes are also involved. One such environmental change is a reduced exposure to pathogens because of improved hygiene. Parasitic helminths modulate the immune system of their hosts and induce type 2 as well as regulatory immune responses. As pro-inflammatory immune responses are crucial for the onset of both type 1 and type 2 diabetes, helminth-induced immunomodulation may prevent diabetes onset and ameliorate insulin sensitivity. Several epidemiological studies in human and experimental animal models support such a protective effect of helminths for autoimmune diabetes. Recent studies further suggest that helminths may also provide such a beneficial effect for type 2 diabetes. In this review we summarize studies that investigated parasitic helminths and helminth-derived products and their impact on both type 1 and type 2 diabetes highlighting potential protective mechanisms.

Cardiovascular disease and type 2 diabetes in evolutionary perspective: A critical role for helminths?

“…AAMs producing resistin-like molecule alpha (REMα) inhibit adipogenesis, while increased anti-inflammatory cytokines (e.g. IL-10) downregulate pro-inflammatory cytokines, increasing insulin sensitivity [34]. Together these factors reduce obesity and insulin resistance, lowering risk of T2DM.…”

“…We evaluate existing experimental evidence from animal models and observational evidence from four human populations living a traditional lifestyle who have been studied intensively (Orumo of Ghana, Flores of Indonesia, Tsimane of Bolivia and Kitava of Trobriand Islands) (‘case studies of cardio-metabolic disease in contemporary preindustrial human societies’ section). Throughout the paper we focus more on CAD than T2DM given two recent reviews examining the role of helminths on T2DM [34, 35]. We conclude by proposing future research directions for evolutionary medicine (‘Future prospects’ section).…”

Filarial Infection or Antigen Administration Improves Glucose Tolerance in Diet-Induced Obese Mice

“…The immunomodulation by helminths enables not only the long-term survival of the parasite within the host, but also affects responses to bystander antigens [9]. Several studies have shown that helminth infections prevent or ameliorate autoimmune diseases like type 1 diabetes (T1D), rheumatoid arthritis, chronic inflammatory bowel disease, and multiple sclerosis [10,11], and clinical studies are currently testing the beneficial effect of Trichuris suis ova treatment on autoimmune diseases [12]. Moreover, in vivo infection studies with the rodent filarial nematode Litomosoides sigmodontis (L.s.)…”

CrudeNecator americanusworm extract diminishes pancreatic islets destruction in diabetic non-obese mice (NOD)

“…Other studies with infections or antigen administration using Schistosoma mansoni, Taenia crassiceps , Heligmosomoides polygyrus, Trichinella spiralis ou Strongyloides venezuelensis showed that helminthes parasites prevented or inhibited DM1 in NOD mice (AJENDRA; BERBUDI; HOERAUF; HÜBNER, 2016). However, this positive effect only happened if antigen administration or infection started before insulitis establishment, usually around 4 weeks old in NOD mice (BERBUDI; AJENDRA; WARDANI;.…”