Detection of Soluble Antigen and DNA of Trypanosoma cruzi in Urine Is Independent of Renal Injury in the Guinea Pig Model

Abstract

The diagnosis of Chagas disease in humans is generally limited to the detection of specific antibodies. Detection of T. cruzi antigens in urine has been reported previously, but is not used in the diagnosis. In this study, soluble T. cruzi antigens and DNA were detected in urine samples and were associated with kidney injury and systemic detection of the parasite. We used 72 guinea pigs infected with T. cruzi Y strain and 18 non-infected guinea pigs. Blood, kidney, heart and urine samples were collected during the acute phase and chronic phase. Urine samples were concentrated by ultrafiltration. Antigens were detected by Western Blot using a polyclonal antibody against trypomastigote excretory-secretory antigen (TESA). T. cruzi DNA was detected by PCR using primers 121/122 and TcZ1/TcZ2. Levels of T. cruzi DNA in blood, heart and kidney were determined by quantitative PCR. T. cruzi antigens (75 kDa, 80 kDa, 120 kDa, 150 kDa) were detected in the acute phase (67.5%) and the chronic phase (45%). Parasite DNA in urine was detected only in the acute phase (45%). Kidney injury was characterized by high levels of proteinuria, kidney injury molecule-1 (KIM-1) and urea, and some histopathological changes such as inflammation, necrosis, fibrosis and scarce parasites. The detection of antigens and DNA in urine was associated with the presence of parasite DNA in blood and heart and with high levels of parasite DNA in blood, but not with the presence of parasite in kidney or kidney injury. These results suggest that the detection of T. cruzi in urine could be improved to be a valuable method for the diagnosis of Chagas disease, particularly in congenital Chagas disease and in immunocompromised patients.

Domestic Pig (Sus scrofa) as an Animal Model for Experimental Trypanosoma cruzi Infection

“…The percentage of animals with positive results for antigen detection changed during the course of observation, with highest percentages during the acute phase (75%, 4/5) and lowest percentages during the early chronic phase (50%, 2/4), suggesting a relationship between levels of parasitemia and excretion of T. cruzi antigens in urine. 37 In addition, T. cruzi DNA (nuclear DNA, 188 bp) was also detected in urine samples of the infected pigs; however, the proportion of animals with positive results (27%, 13/48) was less than the detection of antigens in urine (58%, 28/48) and detection of T. cruzi DNA in blood (71%, 34/48) ( Table 3).…”

“…36,50,51 The molecular weight of the antigenic bands detected in the urine samples of the infected pigs are similar to those detected by our group in other animal models and in humans. 37 The presence of soluble fragments of parasitic DNA (188 bp) in urine can be explained by small fragments of DNA of parasites that have died by apoptosis and subsequently crossed the glomerulus barrier in the kidney. 52 Nevertheless, the presence of antigens and DNA of the parasite in urine was not associated with the presence of the parasites in the kidney, indicating that these molecules come from the systemic circulation.…”

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis

“…Evidence on the capacity of T. cruzi to survive in urine came along with those on Leishmania [117], and T. cruzi amastigotes have been occasionally detected in the kidney [186]. Parasite DNA was detected in the urine of experimentally infected pigs (Sus scrofa) or mice [187][188][189]. The crossing of T. cruzi to urine in experimentally infected mice is apparently independent of renal injuries [189].…”

“…The crossing of T. cruzi to urine in experimentally infected mice is apparently independent of renal injuries [189]. The presence of DNA in urine is associated with the presence of parasite DNA in blood and heart and with a high level of parasite DNA in blood, but not with the presence of parasites in kidney or kidney injury [189][190][191]. The detection of antigens within the urine of patients suffering from acute [192] or chronic CD [193] has opened up some new innovative approaches for diagnosis.…”

“…Parasite DNA was detected in the urine of experimentally infected pigs (Sus scrofa) or mice [187][188][189]. The crossing of T. cruzi to urine in experimentally infected mice is apparently independent of renal injuries [189]. The presence of DNA in urine is associated with the presence of parasite DNA in blood and heart and with a high level of parasite DNA in blood, but not with the presence of parasites in kidney or kidney injury [189][190][191].…”