How do parasitic worms prevent diabetes? An exploration of their influence on macrophage and β-cell crosstalk

Anti-Inflammatory Effects of Helminth-Derived Products: Potential Applications and Challenges in Diabetes Mellitus Management

The global rise in diabetes mellitus (DM), particularly type 2 diabetes (T2D), has become a major public health challenge. According to the "hygiene hypothesis", helminth infections may offer therapeutic benefits for DM. These infections are known to modulate immune responses, reduce inflammation, and improve insulin sensitivity. However, they also carry risks, such as malnutrition, anemia, and intestinal obstruction. Importantly, helminth excretory/secretory products, which include small molecules and proteins, have shown therapeutic potential in treating various inflammatory diseases with minimal side effects. This review explores the anti-inflammatory properties of helminth derivatives and their potential to alleviate chronic inflammation in both type 1 diabetes and T2D, highlighting their promise as future drug candidates. Additionally, it discusses the possible applications of these derivatives in DM management and the challenges involved in translating these findings into clinical practice.

Impact of acute schistosomiasis mansoni and concurrent type 1 diabetes on pancreatic architecture in mice

It is not well understood how type 1 diabetes (T1D) and concomitant acute schistosomiasis mansoni affect pancreatic architecture. Male Swiss mice were administered streptozotocin (single 100 mg/kg i.p.) and thirty days later infected with 80 Schistosoma mansoni cercariae. Mice were divided into groups (n = 5): A (healthy control), B (infected), C (uninfected diabetic), and D (diabetic + infected) and euthanized at week 9 post-infection. Blood glucose levels, biometry, stereology, and pancreatic histology were evaluated. Groups C and D showed hyperglycemia (>200 mg/dL). Group B had a higher (+79%) pancreatic mass than A. The endocrine pancreas showed fewer islets of Langerhans (-62%; -50%) and a smaller islet area (-36%; -30%) in C and D, respectively, compared to A. Group D had a smaller (-37%) islet area than B. The volume density of the islets was reduced (-33%) in group C compared to A. Within the exocrine pancreas, the volume density of the pancreatic parenchyma was reduced in groups B (-29%) and D (-26%), and increased in C (+15%) compared to A. Group D was reduced (-35%) compared to C. Group D showed generalized pancreatitis, including disrupted tissue with multiple nuclei of destroyed acinar cells and lost connective tissue and acinar cells with a paucity of zymogen granules. Pancreatic stellate cells were found around areas of distorted architecture. Paired adult worms were found within the pancreatic vessels. In conclusion, concomitant T1D and schistosomiasis mansoni promote extensive exocrine and endocrine changes in the pancreas, whereas pancreatic involvement begins in acute schistosomiasis.

Excretory/secretory antigens from Trichinella spiralis muscle larvae ameliorate HFD-induced non-alcoholic steatohepatitis via driving macrophage anti-inflammatory activity

No approved effective therapy for non-alcoholic steatohepatitis (NASH) is currently available. Trichinella spiralis (T. spiralis) infection and their products have positive impact on several metabolic diseases. Considering, we firstly investigated the effects of the T. spiralis-derived Excretory-Secretory antigens (ESA) on high fat diet (HFD)-induced NASH mouse models. To further elucidate the mechanism of action, HepG2 cells were incubated with palmitic acid (PA) to construct NASH-like cell model, and then the culture medium supernatant collected from ESA-treated macrophages was applied to intervene the cell model in vitro. In NASH mouse models, ESA significantly alleviated hepatic steatosis and hepatic inflammation, as reflected by reducing pro-inflammatory cytokines and inactivating TLR4/MYD88/NF-κB pathway and NLRP3 inflammasome. Meanwhile, the HFD-induced oxidative stress was restored by ESA through lessening the level of MDA, increasing the activity of T-SOD and enhancing Nrf2 signaling-related proteins, including p-Nrf2, NQO1, HO-1, GPX4, and p-AMPK. Notably, ESA preferentially promoted macrophages polarization toward M2 anti-inflammatory phenotype in vivo and vitro. Moreover, in vitro, intervention of PA-treated HepG2 cells with medium supernatant of ESA-treated macrophages attenuated lipid accumulation, inflammation, as well as oxidative stress. In conclusion, T. spiralis-derived ESA may serve as a novel promising candidate for the treatment of NASH via its properties of driving macrophage anti-inflammatory activity.

Helminth Infections and Diabetes: Mechanisms Accounting for Risk Amelioration

The global prevalence of type 2 diabetes mellitus (T2D) is increasing rapidly, with an anticipated 600 million cases by 2035. While infectious diseases such as helminth infections have decreased due to improved sanitation and health care, recent research suggests a link between helminth infections and T2D, with helminths such as Schistosoma, Nippostrongylus, Strongyloides, and Heligmosomoides potentially mitigating or slowing down T2D progression in human and animal models. Helminth infections enhance host immunity by promoting interactions between innate and adaptive immune systems. In T2D, type 1 immune responses are suppressed and type 2 responses are augmented, expanding regulatory T cells and innate immune cells, particularly type 2 immune cells and macrophages. This article reviews recent research shedding light on the favorable effects of helminth infections on T2D. The potential defense mechanisms identified include heightened insulin sensitivity and reduced inflammation. The synthesis of findings from studies investigating parasitic helminths and their derivatives underscores promising avenues for defense against T2D.

Effect of macrophage polarization on parasitic protection against type 1 diabetes mellitus

Type 1 diabetes mellitus is a chronic disease caused by the destruction of pancreatic beta cells. Based on the hygiene hypothesis, a growing body of evidence suggests a negative association between parasitic infections and diabetes in humans and animal models. The mechanism of parasite-mediated prevention of type 1 diabetes mellitus may be related to the adaptive and innate immune systems. Macrophage polarization is a new paradigm for the treatment of type 1 diabetes mellitus, and different host macrophage subsets play various roles during parasite infection. Proinflammatory cytokines are released by M1 macrophages, which are important in the development of type 1 diabetes mellitus. Parasite-activated M2 macrophages prevent the development of type 1 diabetes mellitus and can influence the development of adaptive immune responses through several mechanisms, including Th2 cells and regulatory T cells. Here, we review the role and mechanism of macrophage polarization in parasitic protection against type 1 diabetes mellitus.

Metabolomics (Non-Targeted) of Induced Type 2 Diabetic Sprague Dawley Rats Comorbid with a Tissue-Dwelling Nematode Parasite

Type 2 diabetes is a non-communicable metabolic syndrome that is characterized by the dysfunction of pancreatic β-cells and insulin resistance. Both animal and human studies have been conducted, demonstrating that helminth infections are associated with a decreased prevalence of type 2 diabetes mellitus (T2DM). However, there is a paucity of information on the impact that helminths have on the metabolome of the host and how the infection ameliorates T2DM or its progression. Therefore, this study aimed at using a non-targeted metabolomics approach to systematically identify differentiating metabolites from serum samples of T2DM-induced Sprague Dawley (SD) rats infected with a tissue-dwelling nematode, Trichinella zimbabwensis, and determine the metabolic pathways impacted during comorbidity. Forty-five male SD rats with a body weight between 160 g and 180 g were used, and these were randomly selected into control (non-diabetic and not infected with T. zimbabwensis) (n = 15) and T2DM rats infected with T. zimbabwensis (TzDM) (n = 30). The results showed metabolic separation between the two groups, where d-mannitol, d-fructose, and glucose were upregulated in the TzDM group, when compared to the control group. L-tyrosine, glycine, diglycerol, L-lysine, and L-hydroxyproline were downregulated in the TzDM group when compared to the control group. Metabolic pathways which were highly impacted in the TzDM group include biotin metabolism, carnitine synthesis, and lactose degradation. We conclude from our study that infecting T2DM rats with a tissue-dwelling nematode, T. zimbabwensis, causes a shift in the metabolome, causing changes in different metabolic pathways. Additionally, the infection showed the potential to regulate or improve diabetes complications by causing a decrease in the amino acid concentration that results in metabolic syndrome.