Uncovering the effects of Giardia duodenalis on the balance of DNA viruses and bacteria in children's gut microbiota

The neglected parasitosis giardiasis is one of the most common intestinal infections worldwide, affecting mainly infants and young children. Giardia duodenalis may disturb the local microbiome, leading to intestinal ecosystem disorders, and altering different processes in the host, such as the immune response. Nevertheless, the alterations promoted by G. duodenalis on the human gut microbiome have not been thoroughly investigated. Here, we characterized the gut microbiota of G. duodenalis-infected children and determine the main alterations promoted by the parasite. To do so, fecal samples of 26 infected and four uninfected children aged 2 to 6 years old were processed for High Efficiency Microarray analysis, in order to describe their bacterial and viral profiles. Then, we quantified the total bacterial population by qPCR and assessed fecal calprotectin levels, which are closely related with gut inflammation. A total of 286 bacteria's species and 17 viruses' strains were identified. Our results revealed no statistically significant differences between G. duodenalis positive and negative groups in the taxa's phyla and families. However, bacterial species diversity was increased in children infected with G. duodenalis (p < 0.05), while the total number of bacteria was decreased (p < 0.05). Considering the virome analysis, 17 different strains were identified, 88% being bacteriophages. The correlation analysis revealed an important disruption in the balance of DNA virus and bacteria within the intestinal microbiota of Giardia-positive children. Our findings constitute the first description of the gut virome of Giardia-infected children and suggest that G. duodenalis infection exerts a modulatory effect on the gut microbiome, promoting local inflammation and altering the equilibrium of the parasite-microbiota-host triad. This highlights the importance of considering polymicrobial associations and understanding the broader context of giardiasis. Overall, our study provides new insights into the complex interactions between intestinal parasites and the microbiota, which may have implications for the development of novel therapeutic interventions in the future.

MRI, FDG-PET/CT and Image-Guidance for Re-Irradiation of Locoregionally Recurrent or Second Primary Head-and-Neck Squamous Cell Carcinoma Patients - Results of a Multicenter Cohort Study

PURPOSE/OBJECTIVE(S)

To investigate patterns of care and prognostic benefits of MRI, FDG-PET/CT and image-guidance in re-irradiation of locoregionally recurrent or second primary head-and-neck squamous cell carcinomas (r/s HNSCCs) within a multicenter cohort study.

MATERIALS/METHODS

Patients receiving re-irradiation for r/s HNSCC between 2009 and 2020 at 16 tertiary cancer centers in Germany were retrospectively analyzed in terms of MRI and FDG-PET/CT usage for treatment planning and regarding image-guidance frequency during re-irradiation. Patterns of use of these modalities over time were analyzed by binary logistic regression analysis, and the association between the usage of these modalities and best locoregional treatment response was analyzed with chi-square tests. Cumulative incidence analyses of locoregional failures with death as competing event were performed.

RESULTS

In the total cohort of 297 patients, 226 (76%) were male, median age was 62 years (IQR, 56-70), and median ECOG was 1 (IQR, 1-2). There were 260 locoregionally recurrent HNSCCs, and 37 second primary HNSCCs; 44 patients (15%) had distant metastases at the time of re-irradiation. MRI and FDG-PET/CT was used for re-irradiation planning in 117 (39%) and 71 patients (24%), respectively. In median, image guidance (IGRT) was performed twice weekly (IQR, 1-5), usually with cone beam CTs or megavolt-CTs, and 85 patients (29%) received daily IGRT during re-irradiation. Usage of MRI (OR = 0.967; 95% CI, 0.892-1.048; p = .416), FDG-PET/CT (OR = 1.053; 95% CI, 0.960-1.156; p = .274), or daily IGRT (OR = 1.057; 95% CI, 0.968-1.115; p = .218) did not increase in frequency over time within the analyzed time span but was significantly dependent on the treatment center (χ2(15), P<.001 for all modalities). Daily IGRT was associated with a higher rate of at least stable disease after re-irradiation as assessed by RECIST criteria (χ2(1) = 4.011, p<.05). There was a trend towards better RECIST-assessed treatment response for MRI (χ2(1) = 3.223, p = .073) and FDG-PET/CT (χ2(1) = 2.792, p = .095) as part of the re-irradiation planning process. Incidence of locoregional failures was not dependent on MRI (SHR = 0.94; 95% CI, 0.67-1.33; p = 0.741, Fine-Gray), FDG-PET/CT (SHR = 0.88; 95% CI, 0.59-1.33; p = 0.552) or daily IGRT (SHR = 0.76; 95% CI, 0.51-1.14, p = 0.182), There was a trend towards lower acute grade 3/4-toxicities in patients receiving daily IGRT (χ2(1) = 3.354, p = 0.067).

CONCLUSION

Our data suggest that daily IGRT may increase disease control and should be regularly applied for re-irradiation of r/s HNSCCs. MRI and FDG-PET/CT usage were not associated with the incidence of locoregional failures after re-irradiation. However, prospective trials with multiparametric MRI and/or FDG-PET/CT for optimal re-irradiation planning are warranted.

Extracellular vesicles in the context of Chagas Disease - A systematic review

Extracellular vesicle (EVs) traffic is considered an important cellular communication process between cells that can be part of a single organism or belong to different living beings. The relevance of EV-mediated cellular communication is increasingly studied and appreciated, especially in relation to pathological conditions, including parasitic disorders, in which the EV release and uptake processes have been documented. In the context of Chagas Disease (CD), EVs have been explored, however, current data have not been systematically revised in order to provide an overview of the published literature and the main results obtained thus far. In this systematic review, 25 studies involving the investigation of EVs in CD were identified. The studies involved Trypanosoma cruzi (Tc)-derived EVs (Tc-EVs), as well as EVs derived from T. cruzi-infected mammalian cells-derived EVs, mainly isolated by ultracentrifugation and poorly characterized. The objectives of the identified studies included the characterization of the protein and RNA cargo of Tc-EVs, as well as investigation of EVs in parasitic infections and immune-related processes. Overall, our systematic review reveals that EVs play critical roles in several mechanisms related to the interaction between T. cruzi and mammalian hosts, their contribution to immune system evasion by the parasite, and to chronic inflammation in the host. Future studies will benefit from the consolidation of isolation and characterization methods, as well as the elucidation of the role of EVs in CD.

Multiparametric analysis of host and parasite elements in new world tegumentary leishmaniasis

Tegumentary leishmaniasis is a tropical disease caused by protozoa of the genus Leishmania. Clinically, the disease presents a broad spectrum of symptoms, the mechanisms underlying the development of lesions remaining to be fully elucidated. In the present work, we performed a correlation and multiparametric analysis to evaluate how parasite- and host-related aspects associate with each other, and with the different clinical manifestations of tegumentary leishmaniasis. This cross-sectional study involved 75 individuals from endemic areas of Brazil, grouped according to their symptoms. Leishmania species were determined by DNA sequencing, and parasite load, antibody production, and cytokine profile were evaluated by kDNA qPCR, ELISA, and flow cytometry. Data were analyzed using the Chi-square test, principal component analysis, canonical discriminant analysis, and correlation analysis. Among the recruited patients, 23 (31%) were asymptomatic, 34 (45%) had primary cutaneous leishmaniasis, 10 (13%) presented recurrent cutaneous leishmaniasis, and eight (11%) had mucocutaneous leishmaniasis. Leishmania species identified included L. amazonensis, L. braziliensis, and L. guyanensis. Surprisingly, no Leishmania RNA virus infection was detected in any sample. In summary, our work showed that parasite load, antibody production, and cytokine levels alone are not determinants for tegumentary leishmaniasis symptoms. However, the correlation analysis allowed us to observe how these factors are correlated to each other within the groups, which revealed a unique network for each clinical manifestation. Our work reinforces the complexity of tegumentary leishmaniasis outcomes - which are associated with multiple host and parasite-related elements and provides a holistic model of the disease.

Insights from the use of erythropoietin in experimental Chagas disease

In addition to the long-established role in erythropoiesis, erythropoietin (Epo) has protective functions in a variety of tissues, including the heart. This is the most affected organ in chronic Chagas disease, caused by the protozoan Trypanosoma cruzi. Despite seven million people being infected with T. cruzi worldwide, there is no effective treatment preventing the disease progression to the chronic phase when the pathological involvement of the heart is often observed. Chronic chagasic cardiomyopathy has a wide variety of manifestations, like left ventricular systolic dysfunction, dilated cardiomyopathy, and heart failure. Since Epo may help maintain cardiac function by reducing myocardial necrosis, inflammation, and fibrosis, this study aimed to evaluate whether the Epo has positive effects on experimental Chagas disease. For that, we assessed the earlier (acute phase) and also the later (chronic phase) use of Epo in infected C57BL/6 mice. Blood cell count, biochemical parameters, parasitic load, and echocardiography data were evaluated. In addition, histopathological analysis was carried out. Our data showed that Epo had no trypanocide effect nor did it modify the production of anti-T. cruzi antibodies. Epo-treated groups exhibited parasitic burden much lower in the heart compared to blood. No pattern of hematological changes was observed combining infection with treatment with Epo. Chronic Epo administration reduced CK-MB serum activity from d0 to d180, irrespectively of T. cruzi infection. Likewise, echocardiography and histological results indicate that Epo treatment is more effective in the chronic phase of experimental Chagas disease. Since treatment is one of the greatest challenges of Chagas disease, alternative therapies should be investigated, including Epo combined with benznidazole.

F18-FDG PET/CT imaging early predicts pathologic complete response to induction chemoimmunotherapy of locally advanced head and neck cancer: preliminary single-center analysis of the checkrad-cd8 trial

Aim

In the CheckRad-CD8 trial patients with locally advanced head and neck squamous cell cancer are treated with a single cycle of induction chemo-immunotherapy (ICIT). Patients with pathological complete response (pCR) in the re-biopsy enter radioimmunotherapy. Our goal was to study the value of F-18-FDG PET/CT in the prediction of pCR after induction therapy.

Methods

Patients treated within the CheckRad-CD8 trial that additionally received FDG- PET/CT imaging at the following two time points were included: 3–14 days before (pre-ICIT) and 21–28 days after (post-ICIT) receiving ICIT. Tracer uptake in primary tumors (PT) and suspicious cervical lymph nodes (LN +) was measured using different quantitative parameters on EANM Research Ltd (EARL) accredited PET reconstructions. In addition, mean FDG uptake levels in lymphatic and hematopoietic organs were examined. Percent decrease (Δ) in FDG uptake was calculated for all parameters. Biopsy of the PT post-ICIT acquired after FDG-PET/CT served as reference. The cohort was divided in patients with pCR and residual tumor (ReTu).

Results

Thirty-one patients were included. In ROC analysis, ΔSUVmax PT performed best (AUC = 0.89) in predicting pCR (n = 17), with a decline of at least 60% (sensitivity, 0.77; specificity, 0.93). Residual SUVmax PT post-ICIT performed best in predicting ReTu (n = 14), at a cutpoint of 6.0 (AUC = 0.91; sensitivity, 0.86; specificity, 0.88). Combining two quantitative parameters (ΔSUVmax ≥ 50% and SUVmax PT post-ICIT ≤ 6.0) conferred a sensitivity of 0.81 and a specificity of 0.93 for determining pCR. Background activity in lymphatic organs or uptake in suspected cervical lymph node metastases lacked significant predictive value.

Conclusion

FDG-PET/CT can identify patients with pCR after ICIT via residual FDG uptake levels in primary tumors and the related changes compared to baseline. FDG-uptake in LN + had no predictive value.

Trial registry

ClinicalTrials.gov identifier: NCT03426657.

The COVID-19 pandemic and its consequences for the diagnosis and therapy of head and neck malignancies

OBJECTIVE

The COVID-19 pandemic and the measures accompanying it have been accused of having a negative influence on the frequency and methods of treatment of various diseases including head and neck cancer (HNSCC). To go further into this assumption, the diagnoses made, and treatments performed at one of Germany's largest head and neck cancer centres were evaluated.

PATIENTS AND METHODS

This study consisted of one single centre and involved a retrospective review of all patients with newly diagnosed or recurrent HNSCC. The diagnosis and treatment methods used in the pre-COVID-19 time period between March 1st, 2019, and March 1st, 2020, were analysed and compared with the COVID-19 time period from April 1st, 2020, until April 1st, 2021. The primary objective was defined as the number of malignant diagnoses and the secondary objectives as the disease stage and the time to therapy.

RESULTS

A total of 612 patients (160♀; mean 63 yrs.) were included. 319 patients (52%) were treated in the pre-COVID-19 time. The two groups did not differ in terms of age (p=0.304), gender (p=0.941), presence of recurrent disease (p=0.866), tumour subsite (p=0.194) or the duration from presentation to the multidisciplinary tumour board until start of therapy (p=0.202). There were no significant differences in the T stage (p=0.777), N stage (p=0.067) or UICC stage (p=0.922). During the pre-COVID-19 period more patients presented with distant metastases (n= 23 vs. n=8; p=0.011).

CONCLUSIONS

This study shows that there was no significant change in either the number and severity of HNSCC diagnoses or the time until start of therapy at this large head and neck cancer centre as a result of the COVID-19 pandemic.

Host DNA repair response to oxidative damage is modulated by Trypanosoma cruzi in a strain-dependent manner

The conservation of genomic integrity and stability is essential for cell survival. DNA Damage Responses (DDRs) are considered of paramount importance for all living beings and involve mechanisms of cell cycle regulation and damage-specific DNA repair pathways. Hydrogen peroxide (H₂O₂) is a compound that, in supraphysiological concentrations, damages biomolecules including the DNA, causing base modifications and strand breaks. There is evidence that Trypanosoma cruzi, the protozoan that causes Chagas disease, interferes in the host cell's DNA metabolism. In order to investigate the influence of T. cruzi infection over the host cell capacity to withstand and repair DNA damage, we analyzed L6 cells infected with Berenice, and Colombiana T. cruzi strains according to their viability, proliferation, morphology, DNA degradation, expression of DNA repair, and cell cycle genes following H₂O₂ treatment. It was noted that T. cruzi infection might act as either a stressor or a protective element of host DNA, depending on the strain and H₂O₂ concentration. Cells infected with Berenice strain and treated with 0.8 mM H₂O₂ presented a reduced DNA damage response intensity (e.g., BER and HR). Infection with T. cruzi Colombiana prevented the activation of DNA repair pathways in response to 0.8mM and 1.6mM H₂O₂ (NER and MMR). Nevertheless, since cellular viability was not significantly compromised in Colombiana-infected cells following the oxidative insult, it is possible that the parasite directly influenced the host DNA repair machinery. Our results support the notion that T. cruzi is able to modulate the host cell DNA metabolism in a strain-dependent manner, an event which can be explored in future drug development strategies.

Quality of Life in Caregivers of Children and Adolescents with Autistic Spectrum Disorder: Development and Validation of the Questionnaire

Studies have shown that children and adolescents with autism and their relatives present a high level of stress and more family problems, impacting parents' and caregivers' quality of life (QoL). Despite studies on this subject, there is no specific questionnaire to evaluate QoL in parents or caregivers of children and adolescents with an autistic spectrum disorder (ASD) in Brazil. Therefore, this study's primary purpose was to develop and validate a specific questionnaire to evaluate QoL in these individuals. The study was performed using the following steps: development of the ASD Parent/caregiver QoL questionnaire (autistic spectrum disorder parent/caregiver quality of life-ASDPC-QoL), subjective evaluation, validation of the questionnaire by the Delphi method, assessment of internal consistency, responsiveness, and reliability of the ASLPC-QoL, and administration of the questionnaire to 881 Brazilian ASD caregivers or parents. ASDPC-QoL comprises 28 questions divided into four domains (social, concerns, physical and mental health) with good psychometric properties (reproducibility, reliability, internal consistency, responsiveness, and validity). Our data showed that worries and physical health were the domains with the lowest scores in ASDPCA-QoL. ASDPCA-QoL did not differ among gender and age of child considering the total and all domains. Older participants (≥41 y/o) presented the best scores for social and worries domains but did not differ in other domains and the total. Parents or caregivers of ASD children diagnosed for more than three years have better mental and physical health domains than those recently diagnosed (up to 1 year) but did not differ in the total and other domains. Individuals with a partner and with the highest educational level present the best score for the social domain. Employed individuals showed better scores than unemployed ones for all domains and the total, except for worries, which did not differ. It also occurred comparing the individuals that do not use antidepressants and the ones that use them. Assessing and better understanding the QoL of caregivers is highly relevant. By understanding the social, worries, physical, and emotional health domains of caregivers, it is possible to track harmful aspects, prevent and treat pathologies, in addition to assisting in the implementation of effective public policies.

Impact of delayed adjuvant therapy after surgery in p16 positive oropharyngeal cancer: a retrospective analysis

OBJECTIVE

This study aimed to clarify the impact of delayed adjuvant therapy on the outcome of HPV associated oropharyngeal squamous cell carcinoma (HPV-OPSCC).

PATIENTS AND METHODS

A total of 157 patients with HPV-OPSCC treated by surgery and adjuvant radiotherapy or chemoradiation therapy were analyzed retrospectively. We divided participants into two groups implementing adjuvant therapy within or after 50 days. Primary endpoints were the rates of locoregional recurrence and distant metastases, overall survival, and disease-specific survival.

RESULTS

Adjuvant treatment began within 50 days (average: 38.8 days) in 79 cases compared to 78 cases after 50 days (average: 71.5 days). Five-year overall survival was 85.7% and 87.4% (p=0.588), the rates of local and regional recurrence were 3.8% and 6.4% (p=0.455) and of distant metastases 5.1% and 9% (p=0.369) implementing adjuvant treatment within or later than 50 days, respectively.

CONCLUSIONS

These results suggest that adjuvant therapy initiated later than seven weeks after primary ablative surgery may still be effective HPV-OPSCC.

Seroprevalence of Trypanosoma cruzi in pregnant women in Midwest Brazil: an evaluation of congenital transmission

Chagas disease (CD) is caused by the protozoan Trypanosoma cruzi and it is mainly acquired through the vector route, however, blood transfusion and congenital transmission are implicated in the spread of the illness worldwide. The congenital route can occur at any stage of pregnancy and its frequency varies. In the Federal District, in Brazil, the frequency of T. cruzi infection in pregnant women and their offspring has not been updated. Thus, the aim of this study was to estimate the prevalence of T. cruzi infection in pregnant women and the rate of congenital transmission in the Federal District. A cross-sectional study was conducted to estimate the seroprevalence of T. cruzi from 2014 to 2016 in the population of pregnant women attended by the public health service throughout the Federal District and a descriptive cohort for the evaluation of congenital transmission. During the study, prenatal data of 98,895 women were consulted and pregnant women registered in 2016, presenting with positive T. cruzi serology, were part of the descriptive cohort. The estimated prevalence of T. cruzi infection in the three years was 0.19% and the congenital transmission rate was 1/40 (2.5%). Our results have shown that, although the main routes of transmission of CD have been interrupted, there is still a risk of congenital transmission in the Federal District. This present study highlights the need for the continuous implementation of a screening program for pregnant women and timely treatment of infected newborns and children.

Repercussion of COVID-19 Pandemic on Brazilians' Quality of Life: A Nationwide Cross-Sectional Study

The COVID-19 outbreak, caused by Sars-Cov-2, was officially declared a global pandemic in February 2020, after an unexpected increase in hospitalization and mortality. When faced with this new disease, social and physical distancing and quarantine emerged as solutions to reduce virus transmission. This article examines the quality of life (QoL) of the Brazilian population's during this period of isolation, due to the COVID-19 pandemic by analyzing; physical, psychological, social, and economic aspects. An online survey was distributed from 27 May to 14 August of 2020. A total of 1859 surveys were completed. Our results indicate that Brazilians were more affected by economic and social aspects than psychological and physical. Unemployed participants and individuals who tested positive for COVID-19 presented the lowest QoL. Females showed worst QoL scores than males, but having children did not influence the score. Higher educational level was associated with a better perception of QoL. Not following social distancing guidelines presented better scores in the psychological domain than the ones following restrict or partial social distancing rules. This study is the first to evaluate adults' QoL related to the Sars-Cov-2 pandemic in Brazil at a national level. Our data may help health authorities identify the main factors affecting the QoL of the Brazilian population, thereby orientating them to recover after the pandemic.

Mechanisms of DNA repair in Trypanosoma cruzi: What do we know so far?

Trypanosoma cruzi is the etiological agent of Chagas Disease, which affects 6-7 million people worldwide. Since the early stages of infection and throughout its life cycle, the parasite is exposed to several genotoxic agents. Furthermore, DNA damage is also part of the mechanism of action of at least a few trypanocidal drugs, including Benznidazole. Thus, it is paramount for the parasite to count on an efficient DNA repair machinery to guarantee genome integrity and survival. The present work provides an up-to-date review of both the conserved and peculiar DNA repair mechanisms described in T. cruzi against oxidative stress, ultraviolet and ionizing radiation, DNA adduct-inducing agents, and Benznidazole. The comprehension of the DNA repair mechanisms of the parasite may shed light on the parasite evolution and possibly pave the way for the development of novel and more effective trypanocidal drugs.

Current trends in the pharmacological management of Chagas disease

Chagas disease (CD) is a tropical neglected illness, affecting mainly populations of low socioeconomic status in Latin America. An estimated 6 to 8 million people worldwide are infected with Trypanosoma cruzi, the etiological agent of CD. Despite being one of the main global health problems, this disease continues without effective treatment during the chronic phase of the infection. The limitation of therapeutic strategies has been one of the biggest challenges on the fight against CD. Nifurtimox and benznidazole, developed in the 1970s, are still the only commercial options with established efficacy on CD. However, the efficacy of these drugs have a proven efficacy only during early infection and the benefits in the chronic phase are questionable. Consequently, there is a growing need for new pharmacological alternatives, either by optimization of existing drugs or by the formulation of new compounds. In the present study, a literature review of the currently adopted therapy, its concomitant combination with other drugs, and potential future treatments for CD was performed, considering articles published from 2012. The revised articles were selected according to the protocol of treatment: evaluation of drug association, drug repositioning and research of new drugs. As a result of the present revision, it was possible to conclude that the use of benznidazole in combination with other compounds showed better results when compared with its use as a single therapy. The search of new drugs has been the strategy most used in pursuing more effective forms of treatment for CD. However, studies have still focused on basic research, that is, they are still in a pre-clinical stage, using methodologies based on in vitro or in animal studies.

In vitro models for investigation of the host-parasite interface - possible applications in acute Chagas disease

Chagas disease (CD), caused by Trypanosoma cruzi, is the main parasitic disease in the Western Hemisphere, with an increasing number of cases, especially in non-endemic regions. The disease is characterized by cardiomegaly and mega viscera, nevertheless, the clinical outcome is hard to predict, underscoring the need for further research into the pathophysiology of CD. Even though most basic and translational research involving CD is performed using in vivo models, in vitro models arise as an ethical, rapidly evolving, and physiologically relevant alternative for CD research. In the present review, we discuss the past and recent in vitro models available to study the host-parasite interface in cardiac and intestinal CD, critically analyzing the possibilities and limitations of state-of-the-art alternatives for the CD host-parasite investigation.

Trypanosomatid infections in captive wild mammals and potential vectors at the Brasilia Zoo, Federal District, Brazil

Background

Conservation projects in zoos may involve translocation of captive animals, which may lead to pathogen spread. Neotropical mammals are important hosts of Trypanosoma cruzi and Leishmania spp. the etiological agents of Chagas disease and Leishmaniasis respectively. Studies of trypanosomatid‐infected mammals and vectors (triatomines and sandflies) in zoos are important for the establishment of surveillance and control measures.

Objectives

We investigated trypanosomatid infections in captive wild mammals, triatomines and sandflies at the Brasília Zoo.

Methods

We collected triatomines during active bimonthly surveys, sampled sandflies using light‐traps and obtained blood samples from 74 mammals between 2016 and 2017. We used quantitative PCR to detect trypanosomatids in vectors and mammals.

Results

We found a colony of 19 Panstrongylus megistus in the porcupine unit and detected T. cruzi infections in five bugs. We captured 17 sandflies of four species including Nyssomyia whitmani and Lutzomyia longipalpis, but no Leishmania infection was detected. qPCR detected 50 T. cruzi‐infected mammals belonging to 24 species and five groups of mammals (Carnivora, Cetartiodactyla, Perissodactyla, Pilosa and Primates); Leishmania DNA was detected in 23 mammals from 15 species, mainly carnivores. We detected trypanosomatid infections in 11 mammals born at the Brasília Zoo.

Conclusions

Our results suggest vector‐borne transmission of T. cruzi among maned wolves; measures to reduce the risk of new infections should therefore be taken. We also report sandfly presence and Leishmania‐infected mammals at the Brasília Zoo. Translocation of wild mammals in and out of the Brasília Zoo should consider the risk of T. cruzi and Leishmania spread.

Intestinal microbiota - A modulator of the Trypanosoma cruzi-vector-host triad

Chagas disease affects millions of people, and it is a major cause of death in Latin America. Prevention and development of an effective treatment for this infection can be favored by a more thorough understanding of T. cruzi interaction with the microbiome of vectors and hosts. Next-generation sequencing technology vastly broadened the knowledge about intestinal bacteria composition, showing that microbiota within each host (triatomines and mammals) is composed by high diversity of species, although few dominant phyla. This fact may represent an ecological balance that was acquired during the evolutionary process of the microbiome-host complex, and that serves to perpetuate this system. In this context, commensal microbiota is also essential to protect hosts, conferring them resistance to pathogens colonization. However, in some situations, the microbiota is not able to prevent infection but only modulate it. Here we will review the role of the microbiota on the parasite-vector-host triad with a focus on the kinetoplastida of medical importance Trypanosoma cruzi. Novel strategies to control Chagas disease based on intestinal microbiome will also be discussed.

Correlation of Parasite Burden, kDNA Integration, Autoreactive Antibodies, and Cytokine Pattern in the Pathophysiology of Chagas Disease

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi (T. cruzi), is the main parasitic disease in the Western Hemisphere. Unfortunately, its physiopathology is not completely understood, and cardiomegaly development is hard to predict. Trying to explain tissue lesion and the fact that only a percentage of the infected individuals develops clinical manifestations, a variety of mechanisms have been suggested as the provokers of CD, such as parasite persistence and autoimmune responses. However, holistic analysis of how parasite and host-related elements may connect to each other and influence clinical outcome is still scarce in the literature. Here, we investigated murine models of CD caused by three different pathogen strains: Colombian, CL Brener and Y strains, and employed parasitological and immunological tests to determine parasite load, antibody reactivity, and cytokine production during the acute and chronic phases of the disease. Also, we developed a quantitative PCR (qPCR) protocol to quantify T. cruzi kDNA minicircle integration into the mammalian host genome. Finally, we used a correlation analysis to interconnect parasite- and host-related factors over time. Higher parasite load in the heart and in the intestine was significantly associated with IgG raised against host cardiac proteins. Also, increased heart and bone marrow parasitism was associated with a more intense leukocyte infiltration. kDNA integration rates correlated to the levels of IgG antibodies reactive to host cardiac proteins and interferon production, both influencing tissue inflammation. In conclusion, our results shed light into how inflammatory process associates with parasite load, kDNA transfer to the host, autoreactive autoantibody production and cytokine profile. Altogether, our data support the proposal of an updated integrative theory regarding CD pathophysiology.

Congenital Chagas disease: alert of research negligence

INTRODUCTION

Chagas disease (CD), a neglected endemic disease in Latin America, has acquired new epidemiological characteristics with an increase in the importance of alternative transmission routes such as congenital transmission. We evaluated the scientific research on this subject.

METHODS

We searched the Scielo, BVS, and PubMed databases from 2006 to 2017.

RESULTS

We identified a small number of published articles, mostly in journals with an impact factor less than 3.0. Studies on human congenital transmission of CD were carried out in only seven different countries.

CONCLUSIONS

Our data highlight the lack of research on congenital CD.

Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests

BACKGROUND

Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals.

OBJECTIVE

This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques.

METHODS

A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis.

FINDINGS

Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%).

CONCLUSION

We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.

Molecular bloodmeal analyses reveal that Trypanosoma cruzi-infected, native triatomine bugs often feed on humans in houses in central Brazil

The identification of bloodmeal sources in triatomine bugs (Hemiptera: Reduviidae) is important in understanding vector-host associations and in measuring the risk for Chagas' disease transmission. The bloodmeal sources of triatomines infected with Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae) caught in houses in central Brazil (Goiás State and the Federal District) were investigated during 2012-2014. Mitochondrial cytochrome b amplicons were used to identify bloodmeals through high-resolution melting and DNA sequencing. Most bugs were found to have fed on either humans (45.7%) or chickens (43.1%). Human blood was detected in Triatoma sordida (n = 22/50 bugs), Triatoma pseudomaculata (n = 7/11 bugs), Panstrongylus megistus (n = 10/24 bugs), Panstrongylus geniculatus (n = 1/3 bugs) and Rhodnius neglectus (n = 18/28 bugs) (all: Hemiptera: Reduviidae). Sequencing identified Necromys (Rodentia: Cricetidae) mouse blood in P. geniculatus and Tropidurus (Squamata: Tropiduridae) lizard blood in T. pseudomaculata and T. sordida. These findings reveal new vector-host associations. The present results suggest frequent contact between humans and T. cruzi-infected triatomines in central Brazil and indicate that Chagas' disease transmission by native vectors is an ongoing threat.

High molecular prevalence of Leishmania in phlebotomine sand flies fed on chicken blood in Brazil

Leishmaniases are endemic in Brazil, where Leishmania infantum has been detected in humans, dogs, cats, and phlebotomine vectors. Monitoring synanthropic vector populations is critical for leishmaniasis control-surveillance in such transmission-prone areas. Here, a suite of molecular approaches were used to assess Leishmania infection prevalence and to identify blood-meal sources in a large sample of sand flies collected in anthropic environments of a Leishmania-transmission area in Mato Grosso do Sul State (Rio Verde de Mato Grosso municipality), Central-West Brazil. We sampled sand flies monthly (January-June 2014 and 2016) in one peri-domestic site within each of six neighborhoods with recent records of human visceral and/or tegumentary leishmaniasis. kDNA-qPCR plus rDNA ITS-sequencing were used to detect and identify Leishmania in pooled female sand flies. Individual engorged females (n = 58) were used for blood-meal analyses through High-Resolution Melting (HRM) targeting the mtDNA cytb gene. Overall, 90.5% of 420 CDC trap-nights yielded vectors, for a total catch of 24,989 sand flies. We sub-sampled and identified 3088 sand flies of 12 species, including 2775 Lutzomyia longipalpis (the most abundant species at all sampling sites) and 297 Nyssomyia whitmani. Female sand flies (n = 1261) were grouped in 159 pools, of which 92 Lu. longipalpis (minimum infection rate [MIR] 8%) and 7 Ny. whitmani pools (MIR 7%) were Leishmania kDNA-positive. Most positive Lu. longipalpis were collected in the 2016 rainy season. Sequencing confirmed L. infantum in Lu. longipalpis samples. HRM analyses identified chicken DNA in 57 sand flies (98.3%), 37 of which were Leishmania DNA-positive (64.9%); human blood was found in just one (Leishmania-negative) female. Our data show ongoing risk of L. infantum transmission to humans in the study area, where Leishmania-infected sandfly vectors are common and heavily rely on chicken blood in the peri-domestic environment.

Molecular detection of Trypanosoma sp. and Blastocrithidia sp. (Trypanosomatidae) in phlebotomine sand flies (Psychodidae) in the Federal District of Brazil

INTRODUCTION

This study describes the occurrence of trypanosomatids in phlebotomines in Brasília, Brazil.

METHODS

Two hundred and ten females of 13 sand fly species were analyzed by polymerase chain reaction (PCR) using different molecular markers (D7 24Sα rRNA, kDNA, and ITS1) and sequencing.

RESULTS

PCR revealed trypanosomatid-positive samples from Nyssomyia whitmani and Evandromyia evandroi, which were negative by kDNA and ITS1 Leishmania-specific PCRs. DNA sequence analysis of D7 24Sα rRNA amplicons indicated the occurrence of Blastocrithidia sp. and Trypanosoma sp. in Nyssomyia whitmani and Evandromyia evandroi, respectively.

CONCLUSIONS

Two trypanosomatid species other than Leishmania sp. were found to circulate in sand flies in Central Brazil.

Radiosensitization by BRAF inhibitor therapy-mechanism and frequency of toxicity in melanoma patients

BACKGROUND

Recent evidence suggests that ionizing radiation may be associated with unexpected side-effects in melanoma patients treated with concomitant BRAF inhibitors. A large multicenter analysis was carried out to generate reliable safety data and elucidate the mechanism.

METHODS

A total of 161 melanoma patients from 11 European skin cancer centers were evaluated for acute and late toxicity, of whom 70 consecutive patients received 86 series of radiotherapy with concomitant BRAF inhibitor therapy. To further characterize and quantify a possible radiosensitization by BRAF inhibitors, blood samples of 35 melanoma patients were used for individual radiosensitivity testing by fluorescence in situ hybridization of chromosomal breaks after ex vivo irradiation.

RESULTS

With radiotherapy and concomitant BRAF inhibitor therapy the rate of acute radiodermatitis ≥2° was 36% and follicular cystic proliferation was seen in 13% of all radiotherapies. Non-skin toxicities included hearing disorders (4%) and dysphagia (2%). Following whole-brain radiotherapy, rates of radiodermatitis ≥2° were 44% and 8% (P < 0.001) for patients with and without BRAF inhibitor therapy, respectively. Concomitant treatment with vemurafenib induced acute radiodermatitis ≥2° more frequently than treatment with dabrafenib (40% versus 26%, P = 0.07). In line with these findings, analysis of chromosomal breaks ex vivo indicated significantly increased radiosensitivity for patients under vemurafenib (P = 0.004) and for patients switched from vemurafenib to dabrafenib (P = 0.002), but not for patients on dabrafenib only. No toxicities were reported after stereotactic treatment.

CONCLUSION

Radiotherapy with concomitant BRAF inhibitor therapy is feasible with an acceptable increase in toxicity. Vemurafenib is a more potent radiosensitizer than dabrafenib.

[Botulinum toxin in the treatment of adult spasticity. An interdisciplinary German 10-point consensus 2010]

Spasticity is one of the major causes of functional impairment in adults with lesions of the central nervous system. For instance, approximately 30% of post-stroke patients suffer from different degrees of spasticity with possible consecutive impairments. Numerous studies or meta-analyses showed that local injections of botulinum toxin in spastic muscles lead to dose-dependent reduction in muscle tone and improvement of passive movements (e. g. facilitated care), especially following repeated injections.However, country-specific regulations and patient-remote administration in German health care often do not allow adequate provision of this therapy. Thus, the present consensus statement based on the EBM analyses of the published international literature tries to highlight recent advances and the standard in the field of local spasticity treatment, aiming to facilitate communication between the decision makers and German reimbursement institutions in health care. Prior to initiation of BoNT-A injections, patient-oriented goals should be identified in a multiprofessional context to assure realistic goals for this specific treatment and patient expectations. In Germany for the treatment of focal spasticity following stroke three products have been approved: Botox® (Pharm Allergan, Ettlingen), Dysport® (Ipsen Pharma, Ettlingen) and Xeomin® (Merz Pharma, Frankfurt/Main). For all preparations safety has been repeatedly shown. Functional improvements have also been illustrated for selected patients concerning hand/arm function and gait. The dose per muscle and the selection of muscles to be injected have to be individualized according to the patient's symptoms and should be accompanied by modern neurorehabilitative therapies such as redression or repetitive activation of the injected and antagonistic muscles.

Autoregulative function in the brain in an endotoxic rat shock model

OBJECTIVE AND DESIGN

Autoregulative function in the brain gets relevant in hypodynamic conditions of a sepsis syndrome. We investigated the temporal pattern and dose dependent effects of LPS-induced shock on autoregulative function in rats.

MATERIAL AND SUBJECTS

Chloralose-anesthetized and mechanically ventilated male CD-rats (n = 30).

TREATMENT

Animals were subjected to vehicle, 1 or 5 mg/kg b.w. lipopolysaccharide (LPS) from E. coli given intravenously.

METHODS

Autoregulative function was tested repeatedly with a carotid compression technique assessing the transient hyperemic response ratio (THRR) in the cortex with laser Doppler flowmetry up to 270 min. THRR data from exsanguination experiments served as controls.

RESULTS

Despite lower blood pressure levels in the high dose group (control: 114 +/- 7 mmHg; 1 mg/kg LPS group: 82 +/- 16 mmHg; 5 mg/kg LPS group: 62 +/- 16 mmHg; p < 0.05) progressive cerebral hyperemia occurred similarly in both groups. Compared to exsanguinations experiments autoregulative compensation for lower blood pressure levels was lacking in the high LPS dose group at the end of experiments.

CONCLUSIONS

Cerebral autoregulation was affected by LPS-induced shock supporting the notion of vasoregulative failure in endotoxic shock.

Bortezomib inhibits human osteoclastogenesis

In multiple myeloma, the overexpression of receptor activator of nuclear factor kappa B (NF-kappaB) ligand (RANKL) leads to the induction of NF-kappaB and activator protein-1 (AP-1)-related osteoclast activation and enhanced bone resorption. The purpose of this study was to examine the molecular and functional effects of proteasome inhibition in RANKL-induced osteoclastogenesis. Furthermore, we aimed to compare the outcome of proteasome versus selective NF-kappaB inhibition using bortezomib (PS-341) and I-kappaB kinase inhibitor PS-1145. Primary human osteoclasts were derived from CD14+ precursors in presence of RANKL and macrophage colony-stimulating factor (M-CSF). Both bortezomib and PS-1145 inhibited osteoclast differentiation in a dose- and time-dependent manner and furthermore, the bone resorption activity of osteoclasts. The mechanisms of action involved in early osteoclast differentiation were found to be related to the inhibition of p38 mitogen-activated protein kinase pathways, whereas the later phase of differentiation and activation occurred due to inhibition of p38, AP-1 and NF-kappaB activation. The AP-1 blockade contributed to significant reduction of osteoclastic vascular endothelial growth factor production. In conclusion, our data demonstrate that proteasomal inhibition should be considered as a novel therapeutic option of cancer-induced lytic bone disease.