Endothelial inflammatory activation is related to myocardial perfusion disturbance in experimental chronic Chagas disease

Background

Microvascular myocardial perfusion defect (MPD) is frequent in chronic Chagas cardiomyopathy (CCC) and may be involved in the pathophysiologic process that leads to left ventricular systolic dysfunction (LVSD). However, there is scarcity of studies addressing the histopathological meaning of MPD in CCC and its correlation with endothelial activation.

Purpose

To investigate the correlations between MPD detected in vivo with functional and histopathological changes in the experimental model of CCC in hamsters.

Methods

24 female Sirius hamsters were investigated 8-months after intraperitoneal infection with 3.5x104 trypomastigote forms of Y-strain of T. cruzi. All animals were submitted to rest high-resolution 99mTc-Sestamibi-SPECT myocardial perfusion scintigraphy and echocardiography in vivo. The area of MPD was assessed through the calculation of polar maps by using a dedicated software (MunichHeart®) and a 13-segments model of LV. After euthanasia, we performed a histopathological study of cardiac inflammation and fibrosis and mRNA expression for TNF-α and ICAM, for assessment of inflammation and endothelial activation, respectively.

Results

Most of the animals presented MPD, n=17 (71%), its extension ranging from 1.4 to 30.3% of LV surface. We observed lower values of LVEF in animals with MPD (38.5±11.2%) when compared with animals without MPD 48.4±9.1%, p=0.04) and a trend to higher intensity of myocardial inflammation (estimated by the number of mononuclear cells) in animals with MPD (540.4±153.6 cell/mm2) vs. without MPD (409.6±130.3 cell/mm2), p=0.09. In addition, animals with MPD presented a higher ICAM (0.02±0.01) expression when compared with animals without MPD (0.01±0.01, p=0.02). There was no difference between groups regarding the extent of fibrosis. The results of the regression and correlation analysis showed that individual values of MPD area presented negative correlation with LVEF (R=−0.6, p=0.001), with echocardiographic wall motion score index (WMSi, R=0.5, p=0.007), and with the number of mononuclear cells (R=0.5, p=0.01). Moreover, an analysis based on myocardial segments (n=312), showed that segments with MPD (n=54) in comparison to those without MPD (n=258) presented higher number of mononuclear cells (608±299.9 cell/mm2 and 478.3±201.1 cell/mm, respectively, p<0.0001) and higher WMSi (1.8±0.9 and 1.2±0.4, respectively, p<0.0001.

Conclusions

MPD is a common finding in experimental model of CCC in hamsters and is correlated with inflammation, endothelial inflammatory activation, and systolic ventricular dysfunction. These results suggest that perfusion defects may be an in vivo surrogate marker for inflammation with potential translational implication for monitoring disease activity.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Fundação de Amparo à Pesquisa do Estado de São Paulo

Blood DNA methylation marks discriminate Chagas cardiomyopathy disease clinical forms

Chagas disease is a parasitic disease from South America, affecting around 7 million people worldwide. Decades after the infection, 30% of people develop chronic forms, including Chronic Chagas Cardiomyopathy (CCC), for which no treatment exists. Two stages characterized this form: the moderate form, characterized by a heart ejection fraction (EF) ≥ 0.4, and the severe form, associated to an EF < 0.4. We propose two sets of DNA methylation biomarkers which can predict in blood CCC occurrence, and CCC stage. This analysis, based on machine learning algorithms, makes predictions with more than 95% accuracy in a test cohort. Beyond their predictive capacity, these CpGs are located near genes involved in the immune response, the nervous system, ion transport or ATP synthesis, pathways known to be deregulated in CCCs. Among these genes, some are also differentially expressed in heart tissues. Interestingly, the CpGs of interest are tagged to genes mainly involved in nervous and ionic processes. Given the close link between methylation and gene expression, these lists of CpGs promise to be not only good biomarkers, but also good indicators of key elements in the development of this pathology.

Reduced T Cell and Antibody Responses to Inactivated Coronavirus Vaccine Among Individuals Above 55 Years Old

CoronaVac is an inactivated SARS-CoV-2 vaccine that has been rolled out in several low and middle-income countries including Brazil, where it was the mainstay of the first wave of immunization of healthcare workers and the elderly population. We aimed to assess the T cell and antibody responses of vaccinated individuals as compared to convalescent patients. We detected IgG against SARS-CoV-2 antigens, neutralizing antibodies against the reference Wuhan SARS-CoV-2 strain and used SARS-CoV-2 peptides to detect IFN-g and IL-2 specific T cell responses in a group of CoronaVac vaccinated individuals (N = 101) and convalescent (N = 72) individuals. The frequency among vaccinated individuals, of whom 96% displayed T cell and/or antibody responses to SARS-CoV-2, is comparable to 98.5% responses of convalescent individuals. We observed that among vaccinated individuals, men and individuals 55 years or older developed significantly lower anti-RBD, anti-NP and neutralization titers against the Wuhan strain and antigen-induced IL-2 production by T cells. Neutralizing antibody responses for Gamma variant were even lower than for the Wuhan strain. Even though some studies indicated CoronaVac helped reduce mortality among elderly people, considering the appearance of novel variants of concern, CoronaVac vaccinated individuals above 55 years old are likely to benefit from a heterologous third dose/booster vaccine to increase immune response and likely protection.

Recurrence of COVID-19 associated with reduced T-cell responses in a monozygotic twin pair

Recurrence of COVID-19 in recovered patients has been increasingly reported. However, the immune mechanisms behind the recurrence have not been thoroughly investigated. The presence of neutralizing antibodies (nAbs) in recurrence/reinfection cases suggests that other types of immune response are involved in protection against recurrence. Here, we investigated the innate type I/III interferon (IFN) response, binding and nAb assays and T-cell responses to severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) with IFN gamma (IFNγ) enzyme-linked spot assay (ELISPOT) in three pairs of young adult monozygotic (MZ) twins with previous confirmed COVID-19, one of them presenting a severe recurrence four months after the initial infection. Twin studies have been of paramount importance to comprehend the immunogenetics of infectious diseases. Each MZ twin pair was previously exposed to SARS-CoV-2, as seen by clinical reports. The six individuals presented similar overall recovered immune responses except for the recurrence case, who presented a drastically reduced number of recognized SARS-CoV-2 T-cell epitopes on ELISPOT as compared to her twin sister and the other twin pairs. Our results suggest that the lack of a broad T-cell response to initial infection may have led to recurrence, emphasizing that an effective SARS-CoV-2-specific T-cell immune response is key for complete viral control and avoidance of clinical recurrence of COVID-19.

Dendritic Cells Expressing MyD88 Molecule Are Necessary and Sufficient for CpG-Mediated Inhibition of IgE Production In Vivo

Elevated levels of immunoglobulin E (IgE) are associated with allergies and other immunological disorders. Sensitization with alum adjuvant favours IgE production while CpG-ODN adjuvant, a synthetic toll-like receptor 9 (TLR9) agonist, inhibits it. The cellular mechanisms underlying in vivo TLR regulation of immunoglobulin production, specially IgE, are still controversial. Specifically, TLR-mediated IgE regulation in vivo is not yet known. In this study we showed that augmented levels of IgE induced by sensitizations to OVA with or without alum adjuvant or with OVA-pulsed dendritic cells (DCs) were inhibited by co-administration of CpG. Notably, CpG-mediated suppression of IgE production required MyD88-expression on DCs but not on B-cells. This finding contrasts with previous in vitro studies reporting regulation of IgE by a direct action of CpG on B cells via MyD88 pathway. In addition, we showed that CpG also inhibited IgE production in a MyD88-dependent manner when sensitization was performed with OVA-pulsed DCs. Finally, CpG signalling through MyD88 pathway was also necessary and sufficient to prevent anaphylactic antibody production involved in active cutaneous anaphylaxis.

Bicistronic DNA vaccines simultaneously encoding HIV, HSV and HPV antigens promote CD8⁺ T cell responses and protective immunity

Millions of people worldwide are currently infected with human papillomavirus (HPV), herpes simplex virus (HSV) or human immunodeficiency virus (HIV). For this enormous contingent of people, the search for preventive and therapeutic immunological approaches represents a hope for the eradication of latent infection and/or virus-associated cancer. To date, attempts to develop vaccines against these viruses have been mainly based on a monovalent concept, in which one or more antigens of a virus are incorporated into a vaccine formulation. In the present report, we designed and tested an immunization strategy based on DNA vaccines that simultaneously encode antigens for HIV, HSV and HPV. With this purpose in mind, we tested two bicistronic DNA vaccines (pIRES I and pIRES II) that encode the HPV-16 oncoprotein E7 and the HIV protein p24 both genetically fused to the HSV-1 gD envelope protein. Mice i.m. immunized with the DNA vaccines mounted antigen-specific CD8⁺ T cell responses, including in vivo cytotoxic responses, against the three antigens. Under experimental conditions, the vaccines conferred protective immunity against challenges with a vaccinia virus expressing the HIV-derived protein Gag, an HSV-1 virus strain and implantation of tumor cells expressing the HPV-16 oncoproteins. Altogether, our results show that the concept of a trivalent HIV, HSV, and HPV vaccine capable to induce CD8⁺ T cell-dependent responses is feasible and may aid in the development of preventive and/or therapeutic approaches for the control of diseases associated with these viruses.

Objective assessment of knee osteroarthritis in parachuters by bioimpedance spectroscopy

The aim of the present study was to derive an objective and noninvasive assessment of osteoarthritis of the knee joint by bioimpedance spectrocopy (BIS). The study was performed in Brazilian Military Parachuters and intends to contribute to the improvement of the early diagnosis of joint degeneration. Twelve male volunteers (24 knee joints) participated in the study. A novel index (ID) to assess the disease was proposed from the raw bioimpedance parameter. This index was compared with a subjective rating (Dejour scale) performed by 3 therapists. The results indicated that the values of ID were significantly different (p0.001) between the control group (class 1 of Dejour) and the pathological group (class 2 or higher). A Spearman correlation of -0.81 between the values of ID and the therapists rating was detected. Despite the need of increasing the sample size, the novel technique seems to be capable of supplying an objective and non-invasive tool for helping the diagnosis of the knee osteoarthritis.

A combined approach for the treatment of cervical vertigo

BACKGROUND

Cervical vertigo is a diagnosis commonly made at both otorhinolaryngologist and chiropractic offices. Hypothesized non-vascular mechanisms are reviewed. Therapeutic approaches have been suggested in the literature, ranging from cervical immobilization to vertebral manipulation.

OBJECTIVE

To characterize the patient population with cervical vertigo and observe therapeutic results of a treatment protocol by using distinct conservative modalities.

METHODS

Fifteen subjects with cervical vertigo were selected from patients presenting with dizziness at an otorhinolaryngology medical office. Diagnosis was based on specific criteria and results of an otoneurologic examination. All patients were submitted to a treatment protocol, including spinal manipulation, manual therapy on affected muscle groups, analgesic electrotherapy, labyrinth sedation, surface electromyography biofeedback, and an exercise program. Evolution of dizziness complaints and related musculoskeletal dysfunction was observed.

RESULTS

Musculoskeletal complaints were present in 93% of the patients, mainly cervical pain, shoulder-girdle pain, and tension-type headache. Median duration of musculoskeletal symptoms was 7.5 years, whereas the median duration of dizziness before the beginning of treatment was 52 days. Treatment duration averaged 5 sessions and 41 days. At the end of treatment, 60% of patients reported remission, 20% reported consistent improvement of vertigo. Remission of musculoskeletal symptoms was observed in 26.7% of patients, and improvement was observed in 60% of patients.

CONCLUSION

Chronic, nontraumatic, cervical and shoulder-girdle dysfunction was an important causal and perpetuating factor of cervical vertigo in the population studied, and a consistent improvement was observed with the use of a conservative treatment protocol involving multiple modalities for patients with cervical vertigo. Further controlled studies are needed to access its validity.

[Ankylosis of deciduous teeth]

The authors reviewed the literature concerning ankylosis of deciduous teeth, with emphasis on the diagnosis, the incidence, the aetiology and the treatment of this manifestation, illustrated with representative clinical cases.