Association between Toxoplasma gondii infection and metabolic syndrome in obese adolescents: A possible immune-metabolic link

Prevalence of the metabolic syndrome in African populations: A systematic review and meta-analysis

BACKGROUND

The metabolic syndrome (MS) is a leading cause of death worldwide. Several studies have found MS to be prevalent in various African regions. However, no specific estimates of MS prevalence in African populations exist. The aim of this study was to estimate the overall prevalence of MS in the African populations.

METHODS

A systematic review was conducted in PubMed, Web of Science, Africa Index Medicus, and African Journal Online Scopus to find studies published up to the 15th of August 2022. Pooled prevalence was calculated based on six diagnostic methods. The pooled prevalence of MS was estimated using a random-effects model. Our risk of bias analysis was based on the Hoy et al. tool. A Heterogeneity (I2) assessment was performed, as well as an Egger test for publication bias. PROSPERO number CRD42021275176 was assigned to this study.

RESULTS

In total, 297 studies corresponding to 345 prevalence data from 29 African countries and involving 156 464 participants were included. The overall prevalence of MS in Africa was 32.4% (95% CI: 30.2-34.7) with significant heterogeneity (I2 = 98.9%; P<0.001). We obtained prevalence rates of 44.8% (95% CI: 24.8-65.7), 39.7% (95% CI: 31.7-48.1), 33.1% (95% CI: 28.5-37.8), 31.6% (95% CI: 27.8-35.6) and 29.3% (95% CI: 25.7-33) using the WHO, revised NCEP-ATP III, JIS, NCEP/ATP III and IDF definition criteria, respectively. The prevalence of MS was significantly higher in adults >18 years with 33.1% (95%CI: 30.8-35.5) compared to children <18 years with 13.3% (95%CI: 7.3-20.6) (P<0.001). MS prevalence was significantly higher in females with 36.9% (95%CI: 33.2-40.7) compared to males with 26.7% (95%CI: 23.1-30.5) (P<0.001). The prevalence of MS was highest among Type 2 diabetes patients with 66.9% (95%CI: 60.3-73.1), followed by patients with coronary artery disease with 55.2% (95%CI: 50.8-59.6) and cardiovascular diseases with 48.3% (95%CI: 33.5-63.3) (P<0.001). With 33.6% (95% CI: 28.3-39.1), the southern African region was the most affected, followed by upper-middle income economies with 35% (95% CI: 29.5-40.6).

CONCLUSION

This study, regardless of the definition used, reveals a high prevalence of MS in Africa, confirming the ongoing epidemiological transition in African countries. Early prevention and treatment strategies are urgently needed to reverse this trend.

Do Intestinal Unicellular Parasites Have a Role in the Inflammatory and Redox Status among the Severely Obese?

The diagnosis of obesity comprises subjects with totally different phenotypes and metabolic profiles. Systemic inflammation and oxidative stress derived from the white adipose tissue are suggested as the link between this disease and the development of insulin resistance and metabolic comorbidities. The presence of unicellular eukaryotic parasites colonizing the human gut ecosystem is a common circumstance, and yet their influence on the inflammatory and redox status of the obese host has not been assessed. Herein, a set of inflammatory and redox biomarkers were assessed together with a parasitological analysis of 97 severely obese subjects. Information was also collected on insulin resistance and on the antioxidant composition of the diet. The global prevalence of intestinal unicellular parasites was 49.5%, with Blastocystis sp. the most prevalent protozoan found (42.3%). Colonized subjects displayed a higher total antioxidant capacity and a trend towards higher extracellular superoxide dismutase activity, regardless of their insulin resistance status, along with lower reduced glutathione/oxidized glutathione (GSH/GSSG) ratios in plasma in the insulin-resistant subgroup. No changes in malondialdehyde levels, or in inflammatory cytokines in plasma, were found in regard to the colonization status. In conclusion, enteric eukaryotic unicellular parasites may play an important role in modulating the antioxidant defenses of an obese host, thus could have beneficial effects with respect to the development of systemic metabolic disorders.

The association between Toxoplasma infection and mortality: the NHANES epidemiologic follow-up study

Background

Toxoplasma gondii has been reported to be associated with higher mortality in patients with schizophrenia. This study aimed to explore the relationship between T. gondii infection and 25-year mortality based on data from the Third National Health and Nutrition Examination Survey (NHANES III) database.

Methods

Cases with serum T. gondii antibody test results were included in this study and the corresponding mortality dataset was obtained from the US National Center for Health Statistics (NCHS). Propensity score matching (PSM) was used to match age and sex between groups. The Cox proportional hazards model was used to evaluate the effect of T. gondii infection on mortality.

Results

A total of 14,181 cases were included in the analysis, of which 3831 (27.0%) were seropositive for T. gondii antibody. The median follow-up time of the whole cohort was 22.5 (interquartile range 16.3, 24.5) years. A total of 5082 deaths were observed in this cohort, a mortality rate of 35.8%. All-cause mortality was significantly higher in the seropositive group than in the seronegative group (50.0% vs 30.6%, P < 0.001). Kaplan–Meier analysis showed a significant difference in the survival time between two groups before and after PSM. Multivariate analysis showed that T. gondii infection was independently associated with higher all-cause mortality after adjusting for potential confounders.

Conclusions

Toxoplasma gondii infection is associated with higher mortality in general population.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05398-1.

The Immune Response in Adipocytes and Their Susceptibility to Infection: A Possible Relationship with Infectobesity

The current obesity pandemic has been expanding in both developing and developed countries. This suggests that the factors contributing to this condition need to be reconsidered since some new factors are arising as etiological causes of this disease. Moreover, recent clinical and experimental findings have shown an association between the progress of obesity and some infections, and the functions of adipose tissues, which involve cell metabolism and adipokine release, among others. Furthermore, it has recently been reported that adipocytes could either be reservoirs for these pathogens or play an active role in this process. In addition, there is abundant evidence indicating that during obesity, the immune system is exacerbated, suggesting an increased susceptibility of the patient to the development of several forms of illness or death. Thus, there could be a relationship between infection as a trigger for an increase in adipose cells and the impact on the metabolism that contributes to the development of obesity. In this review, we describe the findings concerning the role of adipose tissue as a mediator in the immune response as well as the possible role of adipocytes as infection targets, with both roles constituting a possible cause of obesity.

Chemerin as Potential Biomarker in Pediatric Diseases: A PRISMA-Compliant Study

Adipose tissue is the main source of adipokines and therefore serves not only as a storage organ, but also has an endocrine effect. Chemerin, produced mainly in adipocytes and liver, is a natural ligand for chemokine-like receptor 1 (CMKLR1), G-protein-coupled receptor 1 (GPR1) and C-C motif chemokine receptor-like 2 (CCRL2), which have been identified in many tissues and organs. The role of this protein is an active area of research, and recent analyses suggest that chemerin contributes to angiogenesis, adipogenesis, glucose homeostasis and energy metabolism. Many studies confirm that this molecule is associated with obesity in both children and adults. We conducted a systematic review of data from published studies evaluating chemerin in children with various disease entities. We searched PubMed to identify eligible studies published prior to February 2022. A total of 36 studies were selected for analysis after a detailed investigation, which was intended to leave only the research studies. Moreover, chemerin seems to play an important role in the development of cardiovascular and digestive diseases. The purpose of this review was to describe the latest advances in knowledge of the role of chemerin in the pathogenesis of various diseases from studies in pediatric patients. The mechanisms underlying the function of chemerin in various diseases in children are still being investigated, and growing evidence suggests that this adipokine may be a potential prognostic biomarker for a wide range of diseases.

Infection and Immunometabolism in the Central Nervous System: A Possible Mechanistic Link Between Metabolic Imbalance and Dementia

Metabolic syndromes are frequently associated with dementia, suggesting that the dysregulation of energy metabolism can increase the risk of neurodegeneration and cognitive impairment. In addition, growing evidence suggests the link between infections and brain disorders, including Alzheimer's disease. The immune system and energy metabolism are in an intricate relationship. Infection triggers immune responses, which are accompanied by imbalance in cellular and organismal energy metabolism, while metabolic disorders can lead to immune dysregulation and higher infection susceptibility. In the brain, the activities of brain-resident immune cells, including microglia, are associated with their metabolic signatures, which may be affected by central nervous system (CNS) infection. Conversely, metabolic dysregulation can compromise innate immunity in the brain, leading to enhanced CNS infection susceptibility. Thus, infection and metabolic imbalance can be intertwined to each other in the etiology of brain disorders, including dementia. Insulin and leptin play pivotal roles in the regulation of immunometabolism in the CNS and periphery, and dysfunction of these signaling pathways are associated with cognitive impairment. Meanwhile, infectious complications are often comorbid with diabetes and obesity, which are characterized by insulin resistance and leptin signaling deficiency. Examples include human immunodeficiency virus (HIV) infection and periodontal disease caused by an oral pathogen Porphyromonas gingivalis. This review explores potential interactions between infectious agents and insulin and leptin signaling pathways, and discuss possible mechanisms underlying the relationship between infection, metabolic dysregulation, and brain disorders, particularly focusing on the roles of insulin and leptin.