Toxoplasma gondii as a possible causative pathogen of type-1 diabetes mellitus: Evidence from case-control and experimental studies

Seroepidemiology of Toxoplasma gondii in diabetic patients type 2 by enzyme-linked immunosorbent assay method in Zabol City, 2017-2018

Background

Type 2 diabetes mellitus (T2DM) is prone to opportunistic infections, including toxoplasmosis, due to an immunodeficiency system. This study aimed to evaluate the serum of people with T2DM to determine the titer of anti-toxoplasma antibodies in patients and compare it with the control group.

Materials and Methods

720 blood samples have been carried out between October and the end of January 2017 in Sistan, and Baluchestan provinces in southeastern Iran, of these, 360 samples were related to healthy individuals (control), and 360 samples were related to T2DM individuals. The immunoglobulin (Ig) M and IgG enzyme-linked immunosorbent assay methods have been used to detect toxoplasmosis. The data were analyzed using SPSS-19, Chi-square, and Fisher's exact test to compare statistical parameters.

Results

In this cross-sectional study, out of 360 samples of T2DM by ELISA method, 60% samples in diabetic patients and 48.1% in control group were IgG positive (P < 0.05). Nearly 2.5% samples in diabetic patients and 0.3% in control group were IgM positive (P < 0.05).

Conclusion

Anti-toxoplasma antibodies including IgG and IgM were higher in diabetic patient in comparison to control group.

Association between Toxoplasma gondii Infection and Type-1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Type-1 diabetes, an autoimmune disease characterized by damage to pancreatic insulin-producing beta cells, is associated with adverse renal, retinal, cardiovascular, and cognitive outcomes, possibly including dementia. Moreover, the protozoal parasite Toxoplasma gondii has been associated with type-1 diabetes. To better characterize the association between type-1 diabetes and Toxoplasma gondii infection, we conducted a systematic review and meta-analysis of published studies that evaluated the relationship between type-1 diabetes and Toxoplasma gondii infection. A random-effects model based on nine primary studies (total number of participants = 2655) that met our inclusion criteria demonstrated a pooled odds ratio of 2.45 (95% confidence interval, 0.91-6.61). Removing one outlying study increased the pooled odds ratio to 3.38 (95% confidence interval, 2.09-5.48). These findings suggest that Toxoplasma gondii infection might be positively associated with type-1 diabetes, although more research is needed to better characterize this association. Additional research is required to determine whether changes in immune function due to type-1 diabetes increase the risk of infection with Toxoplasma gondii, infection with Toxoplasma gondii increases the risk of type-1 diabetes, or both processes occur.

Pancreatic Pathological Changes in Murine Toxoplasmosis and Possible Association with Diabetes Mellitus

BACKGROUND

Previous studies have reported involvement of Toxoplasma gondii (T. gondii) infections in the pathogenesis of some autoimmune diseases, such as polymyositis, rheumatoid arthritis, autoimmune thyroiditis, and Crohn's disease. However, data on the association between T. gondii infections and Type 1 diabetes mellitus (T1DM) are still controversial. Therefore, in the present study, we aimed to investigate the pancreatic pathological changes in mouse models with acute and chronic toxoplasmosis and their association with T1DM.

MATERIALS AND METHODS

Three groups (10 mice each) of male Swiss Albino mice were used. One group of mice was left uninfected, whereas the second and third groups were infected with the acute virulent T. gondii RH strain and the chronic less virulent Me49 T. gondii strain, respectively. T. gondii-induced pancreatic pathological changes were evaluated by histopathological examination of pancreatic tissues. Moreover, the expression of insulin, levels of caspase-3, and the pancreatic infiltration of CD8⁺ T cells were evaluated using immunohistochemical staining.

RESULTS

Pancreatic tissues of T. gondii-infected animals showed significant pathological alterations and variable degrees of insulitis. Mice with acute toxoplasmosis exhibited marked enlargement and reduced numbers of islets of Langerhans. However, mice with chronic toxoplasmosis showed considerable reduction in size and number of islets of Langerhans. Moreover, insulin staining revealed significant reduction in β cell numbers, whereas caspase-3 staining showed induced apoptosis in islets of Langerhans of acute toxoplasmosis and chronic toxoplasmosis mice compared to uninfected mice. We detected infiltration of CD8⁺ T cells only in islets of Langerhans of mice with chronic toxoplasmosis.

CONCLUSIONS

Acute and chronic toxoplasmosis mice displayed marked pancreatic pathological changes with reduced numbers of islets of Langerhans and insulin-producing-β cells. Since damage of β cells of islets of Langerhans is associated with the development of T1DM, our findings may support a link between T. gondii infections and the development of T1DM.

Organotypic endothelial adhesion molecules are key for Trypanosoma brucei tropism and virulence

Trypanosoma brucei is responsible for lethal diseases in humans and cattle in Sub-Saharan Africa. These extracellular parasites extravasate from the blood circulation into several tissues. The importance of the vasculature in tissue tropism is poorly understood. Using intravital imaging and bioluminescence, we observe that gonadal white adipose tissue and pancreas are the two main parasite reservoirs. We show that reservoir establishment happens before vascular permeability is compromised, suggesting that extravasation is an active mechanism. Blocking endothelial surface adhesion molecules (E-selectin, P-selectins, or ICAM2) significantly reduces extravascular parasite density in all organs and delays host lethality. Remarkably, blocking CD36 has a specific effect on adipose tissue tropism that is sufficient to delay lethality, suggesting that establishment of the adipose tissue reservoir is necessary for parasite virulence. This work demonstrates the importance of the vasculature in a T. brucei infection and identifies organ-specific adhesion molecules as key players for tissue tropism.

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Our study investigates the blood vasculature for T. brucei reservoir establishment

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We show the pancreas is a large extravascular reservoir

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We establish that T. brucei tropism is linked to organotypic adhesion molecules

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Interfering with adhesion molecules impacts parasite virulence and host survival

The Probable Association between Chronic Toxoplasma gondii Infection and Type 1 and Type 2 Diabetes Mellitus: A Case-Control Study

Purpose

The probable association between Toxoplasma gondii (T. gondii) infection and diabetes mellitus (DM) is still controversial, and there are several studies with conflicting results. Thus, this study was performed to assess the possible association between chronic T. gondii infection and type 1 diabetes mellitus (T1DM) and T2DM.

Methods

In this case-control study, a total of 105 diabetic subjects including 36 patients with T1DM and 69 patients with T2DM were recruited. In addition, 150 nondiabetic subjects were enrolled as controls. Each case group had its own control group. Each participant completed a structured questionnaire obtaining demographic information. Serum samples were examined for T. gondii-specific IgG antibody using enzyme-linked immunosorbent assay (ELISA) method.

Results

Analysis revealed that 69.4% and 34.0% of patients with T1DM and control subjects were serologically positive for T. gondii, respectively (odds ratio (OR): 4.41; 95% confidence interval (CI): 1.75–11.06; P=0.001). Moreover, 72.5% of T2DM patients and 29.0% of healthy individuals were seropositive for T. gondii (OR: 6.44; 95% CI: 3.25–12.74; P < 0.001). Among risk factors, only contact with cats was significantly associated with IgG seroprevalence in both T2DM patients (P < 0.001) and control subjects (P=0.045).

Conclusion

Although the results showed that chronic T. gondii infection is significantly associated with T1DM and T2DM, there remain many questions regarding the exact mechanisms of T. gondii in the pathogenesis of DM.

High Prevalence of Toxoplasma gondii Infection in Type I Diabetic Patients

Background

Type I diabetes (TΙDM) is a genetic or autoimmune disorder, which may be stimulated by induced immune system components due to the underlying infectious diseases. This study was undertaken to find out any possible association between Toxoplasma gondii infection and TIDM.

Materials and Methods

One hundred and eighty-two blood samples were taken from individuals who were referred to outpatient clinics in Shiraz city, Southern Iran, during a 6-month period. The age of type I diabetic subjects (n = 91) and the control group (n = 91) was identical, which were less than 30 years. The sera were examined for IgG and IgM antibodies by ELISA and correlated with epidemiological factors such as age, sex, and family history of diabetes.

Results

Out of 91 diabetic patients, 54 (59.3%) were female and 37 (40.7%) were male. The highest frequency of diabetes belonged to 6-10- and 11-15-year groups (P = 0.17). Toxoplasma infection prevalence in diabetic and control groups was 28.6% and 7.7%, respectively (P = 0.001). A significantly positive family history of diabetes was observed between diabetic patients (31 cases, 34.1%) and the control group (3 cases, 3.3%) (P = 0.01). Interestingly, IgG positivity was seen in 13 cases (41.9%) of patients with positive family history of type I diabetes and 13 cases (21.7%) of subjects with no positive family history of type I diabetes (P = 0.04).

Conclusion

Our study showed a higher prevalence of Toxoplasma infection in type I diabetes patients. It is likely that the prevalence of TIDM decreases by increasing hygiene and preventing toxoplasmosis.

Toxoplasma gondii Infection in Diabetes Mellitus Patients in China: Seroprevalence, Risk Factors, and Case-Control Studies

The association between Toxoplasma gondii (T. gondii) infection and diabetes mellitus remains controversial. With the improvement of living standards, the prevalence rate of diabetes is steadily increasing in China. Thus, it is necessary to explore the possible association between toxoplasmosis and diabetes mellitus in China. Hence, case-control studies were conducted to explore the T. gondii seroprevalence and identify the risk factors and possible transmission routes of T. gondii infection in different types of diabetes, including type 1 diabetes (T1DM), type 2 diabetes (T2DM), and gestational diabetes (GDM) patients in China. Four hundred serum samples for each type of diabetes mellitus, matched with 400 control subjects for each group, were collected and examined for anti-T. gondii IgG and IgM antibodies using commercially available enzyme immunoassay kits. The total T. gondii seroprevalence in T1DM, T2DM, and GDM patients was 16.50%, 23.50%, and 21.25%, respectively. Each type of diabetes mellitus patients had a significantly higher T. gondii seroprevalence than the control subjects. Multivariate regression identified three variables as risk factors for T. gondii infection in diabetes patients, including keeping cats at home and consumption of raw oysters for T1DM patients and consumption of raw/undercooked meat and raw oysters for T2DM patients, which may help to guide future research and control policies in diabetes mellitus patients.

Is Toxoplasma gondii infection correlated with nonalcoholic fatty liver disease?- a population-based study

Background

Previous studies have suggested that Toxoplasma gondii (T. gondii) infection might be associated with fatty liver disease. However, the relationship between non-alcoholic fatty liver disease (NAFLD) and T. gondii infection has not been investigated in a large population. We aimed to study the relationship between those two diseases using a population-based dataset from the United States.

Methods

The data were collected from the third National Health and Nutrition Examination Survey (NHANES III) between 1988 and 1994. Statistical analysis was applied to compare the prevalence of NAFLD in anti-T. gondii antibody-positive participants with antibody-negative ones.

Results

A total of 9465 persons with a mean age of 44.33 ± 16.21 years, 46.9% of which were males, were included in the final analysis. Their mean BMI was 27.60 ± 5.96 kg/m². A total of 2520 participants (26.62%) were positive for the T. gondii antibody. There was an increasing trend of seroprevalence of T. gondii with age (P for trend < 0.001). The incidence of NAFLD in the seropositive group was higher than that in the seronegative group (27.10% vs 23.40%, p < 0.001). In addition to this, metabolic biomarkers, including serum lipid, fasting blood-glucose, and uric acid were also significantly higher in the seropositive group. However, multivariate analysis revealed that T. gondii infection was not an independent risk factor for NAFLD. Age was independently correlated with both the prevalence of T. gondii and NAFLD.

Conclusions

Patients with T. gondii infection may have a higher prevalence of NAFLD. Age may have an effect on the increase of NAFLD in the T. gondii seropositive population.