Cibele Maria Prado

The COVID-19 pandemic, caused by SARS-CoV-2, has significantly affected global health, with severe inflammatory responses leading to tissue damage and persistent symptoms. Macrophage-derived extracellular vesicles (EVs) are involved in the modulation of immune responses, but their involvement in SARS-CoV-2-induced inflammation and senescence remains unclear. Triggering receptors expressed on myeloid cell-1 (TREM-1) are myeloid cell receptors that amplify inflammation, described as a biomarker of the severity and mortality of COVID-19. This study investigated the composition and effects of macrophage-derived EVs stimulated by SARS-CoV-2 (MφV-EVs) on the recipient cell response. Our results, for the first time, show that SARS-CoV-2 stimulation modifies the cargo profile of MφV-EVs, enriching them with TREM-1 and miRNA-155 association, along with MMP-9 and IL-8/CXCL8. These EVs carry senescence-associated secretory phenotype (SASP) components, promote cellular senescence, and compromise antibacterial defenses upon internalization. Our findings provide evidence that MφV-EVs are key drivers of inflammation and immune dysfunction, underscoring their potential as therapeutic targets in COVID-19.

Speckle tracking echocardiography (STE) enables early diagnosis of myocardial damage by evaluating myocardial strain. We aimed to study sequential changes in structural and ventricular functional parameters during Chagas disease (CD) natural history in an animal model. 37 Syrian hamsters were inoculated intraperitoneally with Trypanosoma cruzi (Chagas) and 20 with saline (Control). Echocardiography was performed before the infection (baseline), at 1 month (acute phase), 4, 6, and 8 months (chronic phase) using Vevo 2100 (Fujifilm Inc.) ultrasound system. Left ventricular end-diastolic diameter, Left ventricular end-systolic diameter (LVESD), Left ventricular ejection fraction (LVEF), Global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain were evaluated. Tricuspid annular plane systolic excursion (TAPSE) was used to assess right ventricular function. At 8 months, animals were euthanized and LV myocardial samples were analyzed for quantitation of inflammation and fibrosis. LVEF decreased over time in Chagas group and a difference from Control was detected at 6 months (p-value of groups#time interaction = 0.005). There was a pronounced decrease in GLS, GCS and TAPSE in Chagas group (p-value of groups#time interaction = 0.003 for GLS, < 0.001 for GCS and < 0.009 for TAPSE vs Control) since the first month. LVESD, LVEF and GLS were significantly correlated to the number of inflammatory cells (r = 0.41, p = 0.046; r = − 0.42, p = 0.042; r = 0.41, p = 0.047) but not to fibrosis. In the Syrian hamster model of CD STE parameters (GLS and GCS) showed an early decrease. Changes in LVEF, LVESD, and GLS were correlated to myocardial inflammation but not to fibrosis.

Objectives Evaluate whether the RAS dual blockade would induce additional beneficial effects on cardiovascular remodelling when compared to monotherapy in renal hypertensive two kidneys-one clip (2K-1C) rats. Methods Hypertensive 2K-1C and normotensive (2K) rats were treated for 14 days with submaximal doses of losartan (LOS), enalapril (ENA), losartan plus enalapril (LOS + ENA) or vehicle (water). Blood pressure and some parameters of cardiovascular remodelling were evaluated. Results Systolic blood pressure (SBP) was higher in 2K-1C (209 +/- 3 mm Hg,P < .05) than in 2K (113 +/- 1 mm Hg) rats. There was an additional effect in 2K-1C treated with LOS + ENA (153 +/- 9 mm Hg) on lowering SBP when compared to LOS (184 +/- 12 mm Hg) or ENA (177 +/- 9 mm Hg). None of the treatments had effect on SBP in 2K rats. In 2K-1C, cardiomyocyte hypertrophy was reduced by all treatments, although the cardiac hypertrophy indexes remained unchanged. 2K-1C aortas presented medial thickening that was partially reduced by the treatments. Intimal hyperplasia observed in 2K-1C (15.56 +/- 0.89 mu m vs 8.24 +/- 0.80 mu m) was reversed by ENA (9.52 +/- 0.45 mu m) or LOS + ENA (8.17 +/- 0.53 mu m). Collagen deposition was increased in 2K-1C hearts (1.77 +/- 0.16 vs 1.28 +/- 0.09) and aortas (8.1 +/- 0.6 vs 5.2 +/- 0.2). Treatment with LOS reduced (1.12 +/- 0.14%) and ENA (0.81 +/- 0.11%) or LOS + ENA (0.86 +/- 0.11%) additionally diminished collagen only in 2K-1C hearts. Conclusions Submaximal doses of ACEi and/or ARB have inhibitory actions on cardiac remodelling and vascular hypertrophy not entirely dependent on their effects on blood pressure normalization in renovascular hypertensive rats. Combined therapy produced additional reduction in blood pressure than monotherapy despite a similar inhibition on cardiovascular remodelling.

Hypertension causes cardiac hypertrophy, one of the most important risk factors for heart failure (HF). Despite the importance of cardiac hypertrophy as a risk factor for the development of HF, not all hypertrophied hearts will ultimately fail. Alterations of cytoskeletal and sarcolemma-associated proteins are considered markers cardiac remodeling during HF. Dystrophin provides mechanical stability to the plasma membrane through its interactions with the actin cytoskeleton and, indirectly, to extracellular matrix proteins. This study was undertaken to evaluate dystrophin and calpain-1 in the transition from compensated cardiac hypertrophy to HF. Wistar rats were subjected to abdominal aorta constriction and killed at 30, 60 and 90 days post surgery (dps). Cardiac function and blood pressure were evaluated. The hearts were collected and Western blotting and immunofluorescence performed for dystrophin, calpain-1, alpha-fodrin and calpastatin. Statistical analyses were performed and considered significant when p<0.05. After 90 dps, 70% of the animals showed hypertrophic hearts (HH) and 30% hypertrophic+dilated hearts (HD). Systolic and diastolic functions were preserved at 30 and 60 dps, however, decreased in the HD group. Blood pressure, cardiomyocyte diameter and collagen content were increased at all time points. Dystrophin expression was lightly increased at 30 and 60 dps and HH group. HD group showed decreased expression of dystrophin and calpastatin and increased expression of calpain-1 and alpha-fodrin fragments. The first signals of dystrophin reduction were observed as early as 60 dps. In conclusion, some hearts present a distinct molecular pattern at an early stage of the disease; this pattern could provide an opportunity to identify these failure-prone hearts during the development of the cardiac disease. We showed that decreased expression of dystrophin and increased expression of calpains are coincident and could work as possible therapeutic targets to prevent heart failure as a consequence of cardiac hypertrophy.

Dystrophin, an important protein of the dystrophin-glycoprotein complex, has been implicated in the pathogenesis of experimental Chagas disease. It is important for the maintenance of cell shape and contraction force transmission. Dystrophin loss has been related to end-stage cardiac myopathies and proposed as a common route for myocardial dysfunction and progression to advanced heart failure. Evidence suggests that calpains, calcium-dependent proteases, digest dystrophin when the calcium concentration is compatible with their activation. The objective of this in vitro study was to test the hypothesis that dantrolene, a calcium channel blocker, improves structural changes induced by serum from Trypanosoma cruzi-infected mice. Cultured neonatal cardiac myocytes were incubated with serum from T. cruzi-infected mice and treated with dantrolene for 24 h. Immunofluorescence and immunoblotting were performed to evaluate dystrophin and calpain-1 protein expression. The levels of dystrophin decreased 13 % and calpain increased 17 % after incubation of cultured neonatal cardiac myocytes with serum from T. cruzi-infected mice. The treatment with dantrolene restored the dystrophin and calpain levels near control levels. Our results demonstrate that alterations in calcium homeostasis in cardiac myocytes are responsible, in part, for cardiac structural changes in experimentally induced T. cruzi myocarditis and that calpain inhibitors may be beneficial in Chagasic heart disease.

It is hypothesized that chronic increase of availability of acetylcholine, resulting from the effect of antiacetylcholinesterases, may prevent autonomic imbalance and reduce inflammation yielding benefic effects for cardiovascular disorders in hypertension. The effect of long-term administration of antiacetylcholinesterase agents with central and/or peripheral action, i.e., donepezil and pyridostigmine, were investigated on arterial pressure (AP), sympathovagal balance, plasma cytokine levels, and cardiac remodeling in spontaneously hypertensive rats (SHR). Chronic treatment with donepezil or pyridostigmine started before the onset of hypertension. AP was measured by plethysmography every 4 weeks. At the end of 16 weeks of treatment, methylatropine was used to evaluate the cardiac vagal tone; AP and pulse interval (PI) variability were also evaluated followed by plasma and heart collection for analysis. Pyridostigmine, which does not cross the blood–brain barrier, increased cardiac vagal tone, and reduced cardiomyocyte diameter and collagen density, but did not affect the AP and plasma cytokine levels. Donepezil, which crosses the blood–brain barrier, attenuated the development of hypertension, increased cardiac vagal tone, and improved AP and PI variability. Likewise, donepezil reduced the plasma levels of tumor necrosis factor-α, interleukin 6, and interferon γ, besides reducing cardiomyocyte diameter and collagen density. Donepezil attenuated the development of hypertension in SHR probably involving antiinflammatory effects, indicating that acetylcholinesterase inhibition yields benefic effects for antihypertensive therapy.

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (Pvs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.