New insights into Trypanosoma cruzi genetic diversity, and its influence on parasite biology and clinical outcomes

Chagas disease, caused by Trypanosoma cruzi, remains a serious public health problem worldwide. The parasite was subdivided into six distinct genetic groups, called "discrete typing units" (DTUs), from TcI to TcVI. Several studies have indicated that the heterogeneity of T. cruzi species directly affects the diversity of clinical manifestations of Chagas disease, control, diagnosis performance, and susceptibility to treatment. Thus, this review aims to describe how T. cruzi genetic diversity influences the biology of the parasite and/or clinical parameters in humans. Regarding the geographic dispersion of T. cruzi, evident differences were observed in the distribution of DTUs in distinct areas. For example, TcII is the main DTU detected in Brazilian patients from the central and southeastern regions, where there are also registers of TcVI as a secondary T. cruzi DTU. An important aspect observed in previous studies is that the genetic variability of T. cruzi can impact parasite infectivity, reproduction, and differentiation in the vectors. It has been proposed that T. cruzi DTU influences the host immune response and affects disease progression. Genetic aspects of the parasite play an important role in determining which host tissues will be infected, thus heavily influencing Chagas disease's pathogenesis. Several teams have investigated the correlation between T. cruzi DTU and the reactivation of Chagas disease. In agreement with these data, it is reasonable to suppose that the immunological condition of the patient, whether or not associated with the reactivation of the T. cruzi infection and the parasite strain, may have an important role in the pathogenesis of Chagas disease. In this context, understanding the genetics of T. cruzi and its biological and clinical implications will provide new knowledge that may contribute to additional strategies in the diagnosis and clinical outcome follow-up of patients with Chagas disease, in addition to the reactivation of immunocompromised patients infected with T. cruzi.

Performance of microvesicles as biomarkers of clinical outcome in sepsis and trauma: A pilot study

Sepsis remains one of the main causes of death in intensive care unit (ICU) worldwide, despite all technological and scientific advances. Microvesicles (MV) have become promising biomarkers for quick and accurate monitoring of several illnesses. The aim of this pilot study was to characterize and evaluate the performance of MV as biomarker of clinical outcome in septic and trauma patients. For this purpose, 39 subjects, both genders, aging from 18 to 85 years were included in three groups referred as Sepsis, Trauma and Healthy Control. Kinetic analysis of MV was carried out at four consecutive time points: admission (baseline)/T1, 24 h/T2, 72 h/T3 and outcome/T4 of discharge or death. At admission, an overall increase in total MV (Annexin V⁺) was observed in Sepsis.MV CD14⁺ (monocytes) was a putative biomarker to identify trauma patients, while MV CD3⁺ (T-cells) and CD41⁺ (platelets) were qualified to discriminated Trauma from Sepsis. Sepsis (Death) presented an increase in MV Annexin V⁺, CD45⁺, CD16⁺, CD14⁺, and CD41+ in comparison to Sepsis (Discharge). Moreover, Trauma (Death) presented an increase of MV CD3⁺ and CD235⁺ as compared to Trauma (Discharge). Analysing the ROC curve of specific MV evaluated according to performance, an accuracy of 100% was found to segregate the outcome in sepsis, and 95% in trauma. Our findings suggest that MV might be useful as a potential role in discriminating outcome in patients with sepsis/septic shock and trauma with high accuracy. However, further studies with a larger number of participants will be necessary to validate our findings.