Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and other inflammatory mediators in malaria by Plasmodium vivax during enteroparasites coinfection

Malaria is a major health issue with more than 200 million cases occurring annually. Moreover, in Malaria endemic area are frequently observed Malaria-enteroparasite co-infections associated with the modulation of inflammatory response. In this aspect, biomarkers play an important role in the disease prognosis. This study aimed to evaluate inflammatory mediators in malaria during coinfection with enteroparasites. A subset of serum samples already collected was analyzed and divided into four groups: Malaria (n = 34), Co-infected (n = 116), Enteroparasite (n = 120) and Control (n = 95). The serum levels of sTREM-1 and IL-6 were measured by ELISA. TNF-α, and IL-10 levels were previously carried out by flow cytometry. Higher serum levels of sTREM-1 and IL-6 were showed in malaria patients compared to healthy controls. In co-infected malarial patients sTREM-1 serum levels were similar to control group. Interestingly, co-infected malaria patients showed IL-6 serum levels decreased compared to individuals only infected with P. vivax. However, in Malaria patients and co-infected there was a positive correlation between the IL-6 and IL-10 levels (P < 0.0001). This is the first report of sTREM-1 levels in P. vivax infected. Moreover, the results revealing a divergent effect of co-infection with the increased balance between pro-and anti-inflammatory cytokines and reduced IL-6 levels but increases the anemia occurrence. The results also highlight the potential use of IL-6 as a biomarker for P. vivax and enteroparasites coinfection.

TREM-1 amplifies trophoblastic inflammation via activating NF-κB pathway during preeclampsia

INTRODUCTION

Excessive activation of maternal systemic inflammation is one of the underlying causes of pathology during the disease course of preeclampsia (PE). The triggering receptor expressed on myeloid cells-1 (TREM-1) participates in the development and persistence of inflammation. We hypothesized that dysregulated TREM-1 may be involved in the pathogenesis of PE by promoting the secretion of trophoblastic pro-inflammatory cytokines that augment inflammation.

METHODS

The localization of TREM-1 in placenta and the extravillous trophoblast cell line (TEV-1) was determined by immunohistochemical staining. The expression level of TREM-1 and pro-inflammatory cytokines in placentas were compared between normal pregnancies and PE. We used lipopolysaccharide (LPS) to simulate trophoblastic inflammation. TEV-1 cells were transfected with TREM-1 plasmid and si-TREM-1 respectively, and then were incubated with LPS. The expression levels of pro-inflammatory cytokines and key molecules featured in nuclear transcription factor-kappaB (NF-κB) pathway were detected. Transwell assays were used to detect the effects of TREM-1 on cell migration and invasion.

RESULTS

TREM-1 was localized on both villous trophoblasts (VTs) and extravillous trophoblasts (EVTs). TREM-1 and pro-inflammatory cytokines were up-regulated in preeclamptic placenta. Overexpression of TREM-1 promoted the activation of NF-κB pathway and the release of pro-inflammatory factors induced by LPS, and enhanced migration and invasion of TEV-1 cells. Inhibition of TREM-1 significantly attenuated LPS-induced effects and suppressed migration and invasion.

DISCUSSION

This study suggested that TREM-1 was up-regulated in PE, and may promote the production of downstream inflammatory factors by activating NF-κB pathway in trophoblastic cells, thus exerting pro-inflammatory effects in the pathogenesis of PE.

Evaluation of the relationship between TREM-1/TREM-2 ratio and clinical course in COVID-19 pneumonia

OBJECTIVE

The inflammatory/anti-inflammatory balance has an important role in the clinical course of SARS-CoV-2 infection (COVID-19), which has affected over 100 million people since it first appeared in China in December 2019. The aim of this study was to investigate the relationship between triggering receptor expressed on myeloid cells (TREM)-1/TREM-2 ratio and COVID-19 severity.

METHODS

A total of 171 individuals were included in the study: 121 patients who were admitted to the chest diseases department and intensive care unit of our hospital and diagnosed with COVID-19 by real-time PCR of nasopharyngeal swab samples from December 2020 to March 2021 and a control group consisting of 50 asymptomatic health workers in our hospital who had negative real-time PCR results during routine COVID-19 screening.

RESULTS

TREM-1 level was significantly higher in patients with severe disease compared with the moderate and control groups (P = .003, P = .001). TREM-2 levels did not differ significantly in moderate and severe patients (P = .36) but were significantly higher in both patient groups compared with the control group (P = .001 for both). TREM-1/TREM-2 ratio was significantly higher in the severe patient group than in the moderate and control groups (P = .001 for both). In receiver operating characteristic curve analysis of TREM-1/TREM-2 ratio in patients with moderate and severe COVID-19, the area under the curve was 0.723. Using a cut-off value of 0.125 for TREM-1/TREM-2 ratio in the Youden index calculation, the sensitivity was 60% and specificity was 71%.

CONCLUSION

Experience with the positive effects of medical treatments to restore inflammatory balance in the course of COVID-19 is steadily increasing. TREM-1 and TREM-2 have an important role in inflammation and may serve as biomarkers and therapeutic targets in the early treatment and follow-up of COVID-19.

Role of sTREM-1 in predicting mortality of infection: a systematic review and meta-analysis

OBJECTIVES

Several studies have investigated the prognostic value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in patients with infection. However, the result was controversial. Thus, the purpose of the present meta-analysis was to determine the prognostic value of the sTREM-1 level in predicting mortality at the initial stage of infection.

METHODS

The literature was searched in the PubMed, EMBASE, Web of Knowledge and Cochrane databases. A 2×2 contingency table was constructed on the basis of mortality and sTREM-1 levels in patients with infection. 2 authors independently judged study eligibility and extracted data. The prognostic value of sTREM-1 in predicting mortality was determined using a bivariate meta-analysis model. Q-test and I(2) index were used to test heterogeneity.

RESULTS

9 studies were selected from 803 studies. An elevated sTREM-1 level was associated with a higher risk of death in infection, with pooled risk ratio (RR) was 2.54 (95% CI 1.77 to 3.65) using a random-effects model (I(2)=53.8%). With the bivariate random-effects regression model, the pooled sensitivity and specificity of sTREM-1 to predict mortality in infection were 0.75 (95% CI 0.61 to 0.86) and 0.66 (95% CI 0.54 to 0.75), respectively. The diagnostic OR was 6 (95% CI 3 to 10). The overall area under the summary receiver operator characteristic (SROC) curve was 0.76 (95% CI 0.72 to 0.79). When we calculated the sepsis subgroup, the pooled RR was 2.98 (95% CI 2.19 to 4.40). The pooled sensitivity and specificity were 0.74 (95% CI 0.58 to 0.85) and 0.72 (95% CI 0.62 to 0.80), respectively. The overall area under the SROC curve was 0.78 (95% CI 0.74 to 0.81).

CONCLUSIONS

Elevated sTREM-1 concentrations had a moderate prognostic significance in assessing the mortality of infection in adult patients. However, sTREM-1 alone is insufficient to predict mortality as a biomarker.