Myocarditis associated with COVID-19 and its vaccines - a systematic review.

Since the beginning of the COVID-19 (Coronavirus Disease of 2019) pandemic, myocarditis has received much attention and controversy as one of the more worrisome cardiovascular complications. After the availability of highly effective COVID-19 mRNA vaccines in late 2020, myocarditis was also appreciated as an important vaccine-related adverse event. Though the overall frequency of clinically evident viral myocarditis is rare in the general population, young males show a higher predilection for COVID vaccine-induced myocarditis. The severity of COVID-19 viral myocarditis is variable, ranging from very mild to severe, while vaccine-induced myocarditis is usually mild, and rarely a severe or fatal disease. The diagnosis of either COVID-19 or vaccine-induced myocarditis is based on typical clinical features, laboratory investigations, and imaging, preferably with cardiac magnetic resonance. The management of COVID-19 myocarditis is supportive care for mild or moderate disease. For the rare patient who develops severe disease, advanced heart failure therapies such as mechanical circulatory support devices may have to be employed and can be lifesaving. Avoidance of strenuous exercise during the bout of myocarditis and its recovery phase is important. Despite the small but finite risk of vaccine-induced myocarditis, the benefits of protection against COVID-19 disease and its attendant complications far outweigh the risks.

Optimal diuretic strategies in heart failure.

Heart failure (HF) is one of the major causes of morbidity and mortality in the world. According to a 2019 American Heart Association report, about 6.2 million American adults had HF between 2013 and 2016, being responsible for almost 1 million admissions. As the population ages, the prevalence of HF is anticipated to increase, with 8 million Americans projected to have HF by 2030, posing a significant public health and financial burden. Acute decompensated HF (ADHF) is a syndrome characterized by volume overload and inadequate cardiac output associated with symptoms including some combination of exertional shortness of breath, orthopnea, paroxysmal nocturnal dyspnea (PND), fatigue, tissue congestion (e.g., peripheral edema) and decreased mentation. The pathology is characterized by hemodynamic abnormalities that result in autonomic imbalance with an increase in sympathetic activity, withdrawal of vagal activity and neurohormonal activation (NA) resulting in increased plasma volume in the setting of decreased sodium excretion, increased water retention and in turn an elevation of filling pressures. These neurohormonal changes are adaptive mechanisms which in the short term are associated with increased contractility of the left ventricular (LV) and improvement in cardiac output. But chronically, the failing heart is unable to overcome the excessive pressure and volume leading to worsening HF. The primary symptomatic management of ADHF includes intravenous (IV) diuresis to help with decongestion and return to euvolemic status. Even though diuretics have not been shown to provide any mortality benefit, they have been clinically proven to be of significant benefit in the acute decompensated phase, as well as in chronic management of HF. Loop diuretics remain the mainstay of therapy for symptomatic management of HF with use of thiazide diuretics for synergistic effect in the setting of diuretic resistance. Poor diuretic efficacy has been linked with higher mortality and increased rehospitalizations.

Geographic Inequalities in Cardiovascular Mortality in the United States: 1999 to 2018.

OBJECTIVE: To evaluate the trends in cardiovascular, ischemic heart disease (IHD), stroke, and heart failure mortality in the stroke belt in comparison with the rest of the United States. PATIENTS AND METHODS: We evaluated the nationwide mortality data of all Americans from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database from 1999 to 2018. Cause-specific deaths were identified in the stroke belt and nonstroke belt populations using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes. The relative percentage gap was estimated as the absolute difference computed relative to nonstroke belt mortality. Piecewise linear regression and age-period-cohort modeling were used to assess, respectively, the trends and to forecast mortality across the 2 regions. RESULTS: The cardiovascular mortality rate (per 100,000 persons) was 288.3 (95% CI, 288.0 to 288.6; 3,684,273 deaths) in the stroke belt region and 251.2 (95% CI, 251.0 to 251.3; 13,296,164 deaths) in the nonstroke belt region. In the stroke belt region, age-adjusted mortality rates due to all cardiovascular causes (average annual percentage change [AAPC] in mortality rates, -2.4; 95% CI, -2.8 to -2.0), IHD (AAPC, -3.8; 95% CI, -4.2 to -3.5), and stroke (AAPC, -2.8; 95% CI, -3.4 to -2.1) declined from 1999 to 2018. A similar decline in cardiovascular (AAPC, -2.5; 95% CI, -3.0 to -2.0), IHD (AAPC, -4.0; 95% CI, -4.3 to -3.7), and stroke (AAPC, -2.9; 95% CI, -3.2 to -2.2) mortality was seen in the nonstroke belt region. There was no overall change in heart failure mortality in both regions (PAAPC>.05). The cardiovascular mortality gap was 11.8% in 1999 and 15.9% in 2018, with a modest reduction in absolute mortality rate difference (~7 deaths per 100,000 persons). These patterns were consistent across subgroups of age, sex, race, and urbanization status. An estimated 101,953 additional cardiovascular deaths need to be prevented from 2020 to 2025 in the stroke belt to ameliorate the gap between the 2 regions. CONCLUSION: Despite the overall decline, substantial geographic disparities in cardiovascular mortality persist. Novel approaches are needed to attenuate the long-standing geographic inequalities in cardiovascular mortality in the United States, which are projected to increase.

Obesity and Serial NT-proBNP Levels in Guided Medical Therapy for Heart Failure With Reduced Ejection Fraction: Insights From the GUIDE-IT Trial.

Background Obese patients have lower NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. The prognostic implications of achieving NT-proBNP levels ≤1000 pg/mL in obese patients with heart failure (HF) receiving biomarker-guided therapy are not completely known. We evaluated the prognostic implications of obesity and having NT-proBNP levels (≤1000 pg/mL) in the GUIDE-IT (Guiding Evidence-Based Therapy Using Biomarker-Intensified Treatment in HF) trial participants. Methods and Results The risk of adverse cardiovascular events (HF hospitalization or cardiovascular mortality) was assessed using multivariable-adjusted Cox proportional hazard models based on having NT-proBNP ≤1000 pg/mL (taken as a time-varying covariate), stratified by obesity status. The study outcome was also assessed on the basis of the body mass index at baseline. The predictive ability of NT-proBNP for adverse cardiovascular events was assessed using the likelihood ratio test. Compared with nonobese patients, obese patients were mostly younger, Black race, and more likely to be women. NT-proBNP levels were 59.0% (95% CI, 39.5%-83.5%) lower among obese individuals. The risk of adverse cardiovascular events was lower in obese (hazard ratio [HR], 0.48; 95% CI, 0.29-0.59) and nonobese (HR, 0.32; 95% CI, 0.19-0.57) patients with HF who had NT-proBNP levels ≤1000 pg/mL, compared with those who did not. There was no interaction between obesity and having NT-proBNP ≤1000 pg/mL on the study outcome (P>0.10). Obese patients had a greater risk of developing adverse cardiovascular events (HR, 1.39; 95% CI, 1.01-1.90) compared with nonobese patients. NT-proBNP was the strongest predictor of adverse cardiovascular event risk in both obese and nonobese patients. Conclusions On-treatment NT-proBNP level ≤1000 pg/mL has favorable prognostic implications, irrespective of obesity status. NT-proBNP levels were the strongest predictor of cardiovascular events in both obese and nonobese individuals in this trial. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01685840.

Geographic Variation in Cardiovascular Health Among American Adults.

OBJECTIVE: To evaluate the contemporary geographic trends in cardiovascular health in the United States and its relationship with geographic distribution of cardiovascular mortality. METHODS: By use of a retrospective cross-sectional design, the 2011-2017 Behavioral Risk Factor Surveillance System (BRFSS) was queried to determine the age-adjusted prevalence of cardiovascular health index (CVHI) metrics (sum of ideal blood pressure, blood glucose concentration, lipid levels, body mass index, smoking, physical activity, and diet). Cardiovascular health was estimated as both continuous (0 to 7 points) and categorical (ideal, intermediate, poor) variables from the BRFSS. Age-adjusted cardiovascular mortality for 2017 was obtained from the Centers for Disease Control and Prevention WONDER database. RESULTS: Among 1,362,529 American adult participants of the BRFSS 2011-2017 and all American residents in 2017, the CVHI score increased from 3.89±0.004 in 2011 to 3.96±0.005 in 2017 (Ptrend<.001) nationally, with modest improvement across all regions (Ptrend<.05 for all). Ideal cardiovascular health prevalence improved in the northeastern (Ptrend=.03) and southern regions (Ptrend=.002). In 2017, the prevalence of coronary heart disease (6.8%; 95% CI, 6.5% to 7.1%) and stroke (3.7%; 95% CI, 3.4% to 3.9%) was highest in the southern region. The CVHI score (3.81±0.01) and the prevalence of ideal cardiovascular health (12.2%; 95% CI, 11.7% to 12.7%) were lowest in the southern United States. This corresponded to the higher cardiovascular mortality in the southern region (233.0 [95% CI, 232.2- to 33.8] per 100,000 persons). CONCLUSION: Despite a modest improvement in CVHI, only 1 in 6 Americans has ideal cardiovascular health with significant geographic differences. These differences correlate with the geographic distribution of cardiovascular mortality. An urgent unmet need exists to mitigate the geographic disparities in cardiovascular morbidity and mortality.

Mortality Due to Mitral Regurgitation Among Adults in the United States: 1999-2018.

OBJECTIVE: To evaluate the nationwide trends in mortality due to mitral regurgitation (MR) among American adults from 1999 to 2018. PATIENTS AND METHODS: Trends in mortality due to MR were assessed using retrospective cross-sectional analyses of nationwide mortality data from death certificates of all American residents between January 1, 1999, and December 31, 2018, using the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database. Piecewise linear regression was used to evaluate the trends in the overall population and in subgroups. RESULTS: Among 45,982 deaths due to MR during the study period, higher mortality rates were seen in older White females from the western United States. In 1999, the crude and age-adjusted mortality rates were 27.4 (95% CI, 26.3 to 28.4) and 27.5 (95% CI, 26.4 to 28.5) per 1,000,000 persons, respectively. By 2018, these rates declined to 18.0 (95% CI, 17.3 to 18.7) and 17.7 (95% CI, 17.0 to 18.4) per 1,000,000 persons, respectively (P<.001 for trend for both). Crude mortality rates declined from 1999 to 2012 (annual percentage change [APC], -4.1 (95% CI, -4.6 to -3.6) but then increased after 2012 (APC, 2.6 [95% CI, 0.8 to 4.4; P<.001 for change in trend]). The age-adjusted mortality rates declined from 1999 to 2012 (APC, -3.9 [95% CI, -4.4 to -3.4]) but subsequently increased after 2012 (APC, 1.4 [95% CI, -0.4 to 3.2; P<.001 for change in trend]). The observed decrease was consistent across age, sex, race, geographic region, and urbanization subgroups (P<.05 for all). CONCLUSION: Mortality due to MR in American adults declined at an annual rate of approximately 4% until 2012 and has since then increased by about 1.5% annually. These mortality trends warrant further investigation.

Geographic Variation in Racial Disparities in Health and Coronavirus Disease-2019 (COVID-19) Mortality.

OBJECTIVE: To evaluate the race-stratified state-level prevalence of health determinants and the racial disparities in coronavirus disease 2019 (COVID-19) cumulative incidence and mortality in the United States. PATIENTS AND METHODS: The age-adjusted race-stratified prevalence of comorbidities (hypertension, diabetes, dyslipidemia, and obesity), preexisting medical conditions (pulmonary disease, heart disease, stroke, kidney disease, and malignant neoplasm), poor health behaviors (smoking, alcohol abuse, and physical inactivity), and adverse socioeconomic factors (education, household income, and health insurance) was computed in 435,139 American adult participants from the 2017 Behavioral Risk Factor Surveillance System survey. Correlation was assessed between health determinants and the race-stratified COVID-19 crude mortality rate and infection-fatality ratio computed from respective state public health departments in 47 states. RESULTS: Blacks had a higher prevalence of comorbidities (63.3%; 95% CI, 62.4% to 64.2% vs 55.1%; 95% CI, 54.7% to 55.5%) and adverse socioeconomic factors (47.0%; 95% CI, 46.0% to 47.9% vs 30.9%; 95% CI, 30.6% to 31.3%) than did whites. The prevalence of preexisting medical conditions was similar in blacks (30.4%; 95% CI, 28.8% to 32.1%) and whites (30.8%; 95% CI, 30.2% to 31.4%). The prevalence of poor health behaviors was higher in whites (57.2%; 95% CI, 56.3% to 58.0%) than in blacks (50.2%; 95% CI,46.2% to 54.2%). Comorbidities and adverse socioeconomic factors were highest in the southern region, and poor health behaviors were highest in the western region. The cumulative incidence rate (per 100,000 persons) was 3-fold higher in blacks (1546.4) than in whites (540.4). The crude mortality rate (per 100,000 persons) was 2-fold higher in blacks (83.2) than in whites (33.2). However, the infection-fatality ratio (per 100 cases) was similar in whites (6.2) and blacks (5.4). Within racial groups, the geographic distribution of health determinants did not correlate with the state-level COVID-19 mortality and infection-fatality ratio (P>.05 for all). CONCLUSION: Racial disparities in COVID-19 are largely driven by the higher cumulative incidence of infection in blacks. There is a discordance between the geographic dispersion of COVID-19 mortality and the regional distribution of health determinants.

A Case of Heart Failure in a Patient With Systemic Lupus Erythematosus.

Patients with systemic lupus erythematosus (SLE) can present with multiple cardiovascular pathologies, including pulmonary hypertension, valvular disease, pericarditis, myocarditis, and premature atherosclerosis. SLE medications can also cause cardiovascular side effects. We present a patient who developed a severe cardiomyopathy secondary to the hydroxychloroquine prescribed to treat her SLE. (Level of Difficulty: Beginner.).

Remote lung injury after experimental intestinal ischemia-reperfusion in horses.

Ischemia followed by reperfusion leads to release of toxic molecules into the circulation, and these molecules may cause injury in remote organs such as the lung. Horses commonly suffer from episodes of intestinal ischemia-reperfusion (IR) due to intestinal twisting/strangulation followed by repair. Because there is no evidence of lung injury associated with IR in horses, we designed a study to characterize the intestinal IR-associated lung inflammation and determine the effect of lidocaine on lung inflammation in IR horses. Lung tissues were collected from non-anesthetized (n=4) and anesthetized (n=4) control horses and horses (n=12) after 70 minutes of ischemia followed by 60 minutes of reperfusion. Horses in IR groups received Lactated Ringer's Solution (LRS; n=6) or lidocaine (n=6) intravenously. Control lungs had normal histology but lungs from IR horses showed moderate accumulation of neutrophils in blood vessels and airways. We found increased staining for TLR4, IL-8, TLR9, and von Willebrand factor (vWF) along with aggregates of vWF-positive platelets in lung vessels of IR horses compared to the controls. Lung TNFα was significantly increased in IR horses compared to the control horses (P<0.05). Neutrophil numbers, but not MPO concentrations, were significantly lower, while macrophage numbers were higher in the IR group receiving lidocaine compared to the LRS horses (P<0.05). We conclude that intestinal IR leads to remote lung injury characterized by recruitment of inflammatory cells and expression of inflammatory molecules in horses, and lidocaine may ameliorate lung inflammation following intestinal IR.

Angiostatin inhibits acute lung injury in a mouse model.

Acute lung injury is marked by profound influx of activated neutrophils, which have delayed apoptosis, along with fluid accumulation that impairs lung function and causes high mortality. Inflammatory and antimicrobial molecules, such as reactive oxygen species from activated neutrophils with prolonged lifespan, cause tissue damage and contribute to lung dysfunction. Angiostatin, an endogenous antiangiogenic molecule, is expressed in the lavage fluid of patients with acute respiratory distress syndrome and modifies neutrophil infiltration in a mouse model of peritonitis. Our aim was to investigate the therapeutic role of angiostatin in acute lung injury. We analyzed bronchoalveolar lavage and lung tissues from C57BL/6 mouse model of Escherichia coli LPS-induced acute lung injury to assess the effects of angiostatin treatment. Subcutaneous angiostatin administered at 5 h after LPS treatment reduces histological signs of inflammation, protein accumulation, lung Gr1+ neutrophils, myeloperoxidase activity, and expression of phosphorylated p38 MAPK in lung tissues and peripheral blood neutrophils, while increasing the number of apoptotic cells in the lungs without affecting the levels of macrophage inflammatory protein-1 α, IL-1ß, keratinocyte chemoattractant, and monocyte chemoattractant protein-1 in lavage and lung homogenates at 9 and 24 h after LPS treatment. In contrast, angiostatin administered intravenously 5 h after LPS treatment did not reduce histological sign of inflammation, BAL cell recruitment, and protein concentration at 9 h of LPS treatment. We conclude that angiostatin administered subcutaneously after LPS challenge inhibits acute lung inflammation up to 24 h after LPS treatment.

Immuno-phenotypic and functional characterization of rabbit pulmonary intravascular macrophages.

Pulmonary intravascular macrophages (PIMs) are present in species such as cattle, sheep and horse and promote acute lung inflammation (ALI). Rabbits are often used as a model of ALI but there is controversy about the presence of PIMs in these species. Rabbits were treated with 10 mg/kg of gadolinium chloride intravenously (GC; n = 6) or saline (n = 6) followed by euthanasia at 48 h post-treatment to determine the presence of PIMs. In a subsequent study, rabbits were pre-treated with GC or 0.9 % saline followed by 100 µg/kg of E. coli lipopolysaccharide intravenously 48 h later. Rabbits were euthanized 24 h post-LPS treatment. Light and electron microscopy showed that PIMs attached to the capillary endothelium and were positive for RAM-11 anti-macrophage antibody. While GC treatment induced apoptotic PIMs, there was no difference in the PIM number between control and GC-treated rabbits. Rabbits administered with LPS were 3.5 times more likely to die before the end of the 24-h period than those pre-treated with GC. Lung heterophil accumulation and IL-1ß, TNFα and IL-6 mRNA expression were significantly higher in rabbits administered with LPS compared to those administered with GC before the LPS injection. PIMs from the LPS-treated rabbits were positive for TNFα. Lung, BAL and serum IL-8 and MCP-1 expression was not different between LPS rabbits with or without pre-treatment with GC. We conclude that rabbit lungs contain PIMs and that their depletion reduces endotoxin-induced lung inflammation. The presence of PIMs in rabbit lungs may need to be considered while using rabbit to model acute lung injury.

Comparison of the response to experimentally induced short-term inflammation in the temporomandibular and metacarpophalangeal joints of horses.

OBJECTIVE: To investigate the relationship between inflammatory responses of the temporomandibular joint (TMJ) and the metacarpophalangeal (MCP) joint in clinically normal horses. ANIMALS: 7 mature horses. PROCEDURES: In each horse, 1 TMJ and 1 MCP joint were injected with lipopolysaccharide (LPS; 0.0025 µg). The contralateral TMJ and MCP joint were injected with saline (0.9% NaCl) solution. Synovial fluid samples were collected from all 4 joints over 24 hours after injection. Concentrations of interleukin-6, tumor necrosis factor-α, transforming growth factor-ß, and total protein were measured via immunoassay. Horses were assessed for clinical signs of joint inflammation at each time point. RESULTS: Concentrations of interleukin-6 were not significantly different between LPS-injected MCP joints and TMJs at any time point. Transforming growth factor-ß concentrations were significantly increased in MCP joints, compared with concentrations in TMJs, at 12 and 24 hours after injection. Tumor necrosis factor-α concentrations were significantly higher in LPS-injected TMJs than in LPS-injected MCP joints at 1 and 6 hours after injection. Total protein concentration did not differ significantly between LPS-injected MCP joints and TMJs. Injection of LPS induced clinical inflammation at all time points; additionally, 2 MCP joints (but no TMJs) had an inflammatory response to injection of saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: The inflammatory response to LPS appeared to be attenuated more quickly in TMJs than in MCP joints of horses. The difference in response suggested that a lack of clinical osteoarthritis in the TMJ of horses could be attributable to a difference in cytokine response.

RGD-tagged helical rosette nanotubes aggravate acute lipopolysaccharide-induced lung inflammation.

Rosette nanotubes (RNT) are a novel class of self-assembled biocompatible nanotubes that offer a built-in strategy for engineering structure and function through covalent tagging of synthetic self-assembling modules (G∧C motif). In this report, the G∧C motif was tagged with peptide Arg-Gly-Asp-Ser-Lys (RGDSK-G∧C) and amino acid Lys (K-G∧C) which, upon co-assembly, generate RNTs featuring RGDSK and K on their surface in predefined molar ratios. These hybrid RNTs, referred to as K(x)/RGDSK(y)-RNT, where x and y refer to the molar ratios of K-G∧C and RGDSK-G∧C, were designed to target neutrophil integrins. A mouse model was used to investigate the effects of intravenous K(x)/RGDSK(y)-RNT on acute lipopolysaccharide (LPS)-induced lung inflammation. Healthy male C57BL/6 mice were treated intranasally with Escherichia coli LPS 80 µg and/or intravenously with K9°/RGDSK¹°-RNT. Here we provide the first evidence that intravenous administration of K9°/RGDSK¹°-RNT aggravates the proinflammatory effect of LPS in the mouse. LPS and K9°/RGDSK¹°-RNT treatment groups showed significantly increased infiltration of polymorphonuclear cells in bronchoalveolar lavage fluid at all time points compared with the saline control. The combined effect of LPS and K9°/RGDSK¹°-RNT was more pronounced than LPS alone, as shown by a significant increase in the expression of interleukin-1ß, MCP-1, MIP-1, and KC-1 in the bronchoalveolar lavage fluid and myeloperoxidase activity in the lung tissues. We conclude that K9°/RGDSK¹°-RNT promotes acute lung inflammation, and when used along with LPS, leads to exaggerated immune response in the lung.

Rosette nanotubes inhibit bovine neutrophil chemotaxis.

Migration of activated neutrophils that have prolonged lifespan into inflamed organs is an important component of host defense but also contributes to tissue damage and mortality. In this report, we used biologically-inspired RGD-tagged rosette nanotubes (RNT) to inhibit neutrophil chemotaxis. We hypothesize that RGD-RNT will block neutrophil migration through inhibition of MAPK. In this report, RNT conjugated to lysine (K-RNT) and arginine-glycine-aspartic acid-serine-lysine (RGDSK-RNT) were co-assembled in a molar ratio of 95/5. The effect of the resulting composite RNT (RGDSK/K-RNT) on neutrophil chemotaxis, cell signaling and apoptosis was then investigated. Exposure to RGDSK/K-RNT reduced bovine neutrophil migration when compared to the non-treated group (p<0.001). Similar effect was seen following treatment with ERK1/2 or p38 MAPK inhibitors. Phosphorylation of the ERK1/2 and p38 MAPK was inhibited at 5 min by RGDSK/K-RNT (p<0.05). The RGDSD/K-RNT did not affect the migration of neutrophils pre-treated with αvß3 integrin antibody suggesting that both bind to the same receptor. RGDSK/K-RNT did not induce apoptosis in bovine neutrophils, which was suppressed by pre-exposing them to LPS (p<0.001). We conclude that RGDSK/K-RNT inhibit phosphorylation of ERK1/2 and p38 MAPK and inhibit chemotaxis of bovine neutrophils.

Expression and activity of N-myristoyltransferase in lung inflammation of cattle and its role in neutrophil apoptosis.

N-myristoyltransferase (NMT) attaches a 14 carbon fatty acid, myristic acid, to the N-terminal glycine residue of proteins. NMT exists in two isoforms NMT1 and NMT2. Myristoylated proteins play critical roles in protein-protein interactions, cell signaling and oncogenesis. Although elevated expression of NMT1 has been described in colorectal carcinoma, its expression and roles in normal and inflamed lungs of the cattle are unknown. Therefore, we investigated the expression and activity of NMT in a bovine model of lung inflammation induced with Mannheimia hemolytica and in vitro in neutrophils and macrophages. Western blots revealed increased expression of NMT1 in lungs from infected animals compared to control animals. Total NMT activity was reduced in inflamed lungs compared to control animals (p < 0.05) along with increased expression of enolase, a putative inhibitor of NMT. NMT1 staining was observed in the septum, vascular endothelium and the epithelium in the lungs from control as well as infected calves. NMT1 expression was intense in neutrophils in the necrotic areas in the inflamed lungs. Immuno-electron microscopy localized NMT1 in cytoplasm and nuclei of endothelium, pulmonary intravascular macrophages and airway epithelium. Total NMT activity and NMT1 expression were increased in neutrophils and macrophages exposed to Escherichia coli LPS in vitro. NMT knockdown increased apoptosis in activated neutrophils. This is the first report demonstrating expression of NMT in normal and inflamed lungs and a novel role for NMT in regulation of neutrophil lifespan.

Expression and activities of N-myristoyltransferase and calcineurin in normal and inflamed lungs.

The role of N-myristoyltransferase and calcineurin is well established in signaling pathways. However, there are no data on their expression and activities in normal and inflamed lungs. The mechanisms of lung inflammation induced following administration of lipopolysaccharides (LPS) or exposure to swine barn air remain unclear. Therefore, we examined expression and activities of N-myristoyltransferase and calcineurin in normal and inflamed lungs of rats. Histopathology showed acute inflammation in the lungs of rats exposed to barn air or LPS but not of control rats. There was no difference in the activities of N-myristoyltransferase and calcineurin among the control, barn-exposed, and LPS-treated rat lungs. Although N-myristoyltransferase and calcineurin were localized in airway epithelium, blood vessel walls, alveolar macrophages, and septa in the lungs of rats from all the groups, the staining intensity was increased in the lungs from rats exposed to intravenous LPS or barn air. Densitometric analyses of Western blots of 55- and 60-kDa polypeptide bands corresponding to N-myristoyltransferase and calcineurin, respectively, in the lung homogenates revealed no differences among the groups. These results show that expression of myristoyltransferase and calcineurin in lung epithelium and endothelium and a cell-specific increase in immunohistochemical expression.

Expression of toll-like receptor 9 in horse lungs.

Toll-like receptor 9 (TLR9) has been found to be the main receptor to respond to bacterial DNA in a wide variety of species. Recent work has shown that TLR9 is expressed in a diverse set of cells within the lung. However, much of this data has been centered on human and mouse cell culture lines or primary cultures and very little is known of TLR9 expression in intact lung, especially that of the horse. Here we show that TLR9 is expressed in the lungs of horses in a wide variety of cells. In particular, we note expression in pulmonary intravascular macrophages (PIMs), alveolar macrophages, bronchial epithelial cells, and type-II cells amongst others. Immunogold electron microscopy localized TLR9 in nuclei, cytoplasm, and plasma membrane of various lung cells. The data also show that E. coli lipopolysaccharide significantly increased expression of TLR9 mRNA in lungs and the number of cells in the lung septa that were positive for TLR9 protein. Protein expression was seen in airway epithelium, vascular endothelium, and inflammatory cells in blood vessels. Intravenous administration of gadolinium chloride, which depletes macrophages, before the lipopolysaccharide treatment significantly inhibited the LPS-induced increase in TLR9 mRNA in the lungs of the horses. We conclude that TLR9 is expressed in lung cells including PIMs and that the lipopolysaccharide treatment increases TLR9 mRNA expression. The increase in TLR9 mRNA is eliminated by depletion of PIMs, implicating these cells as a major source of TLR9 in the equine lung.

Transgenic expression of coat protein gene of Rice tungro bacilliform virus in rice reduces the accumulation of viral DNA in inoculated plants.

Rice tungro, a devastating disease of rice in south and southeast Asia, is caused by the joint infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). In order to obtain transgenic resistance against RTBV, indica rice cultivar Pusa Basmati-1 was transformed to express the coat protein (CP) gene of an Indian isolate of RTBV. Rice plants containing the transgene integrated in low copy numbers were obtained, in which the CP was shown to accumulate in the leaf tissue. The progenies representing three independent transformation events were challenged with Indian isolates of RTBV using viruliferous Green leafhoppers, and the viral titers in the inoculated plants were monitored using DNA dot-blot hybridization. As compared to non-transgenic controls, two independent transgenic lines showed significantly low levels of RTBV DNA, especially towards later stages of infection and a concomitant reduction of tungro symptoms.

The role of RGD-tagged helical rosette nanotubes in the induction of inflammation and apoptosis in human lung adenocarcinoma cells through the P38 MAPK pathway.

The rosette nanotubes (RNTs) are a class of biologically inspired, self-assembling, metal-free, hydrophilic nanotubes, which hold tremendous potential as targeted drug delivery vehicles. We investigated the cell signaling events caused by lysine-functionalized RNTs (K-RNT) co-assembled with Arg-Gly-Asp-Ser-Lys-functionalized RNTs (RGDSK-RNT) for induction of inflammation and apoptosis in human adenocarcinoma (Calu-3) cells. When co-assembled in a ratio of 1:10 microM these composite RNTs (referred to as RGDSK/K-RNTs) rapidly induced phosphorylation of P38 mitogen-activated protein kinase (MAPK) within 2 min. Higher concentrations of RGDSK/K-RNTs (>10:100 microM) resulted in a P38 MAPK-dependent increase in secretion of TNF-alpha. RGDSK/K-RNTs (1:10-40:400 microM) also caused a concentration- and P38 MAPK-dependent increase in caspase-3 activity and DNA fragmentation in Calu-3 cells at 18 h of exposure. Over-expression of pro-apoptotic genes including caspase-3, BAK1, CIDEB, TP53BP2, FAS, TNF and FASLG supported pro-apoptotic behaviors of these RNTs. We conclude that RGDSK/K-RNTs induce phosphorylation of P38 MAPK, which regulate secretion of TNF-alpha, activation of caspase-3 and apoptosis in Calu-3 cells. These results suggest that the RNTs could be used as a drug to induce apoptosis in cancer cells or as a versatile platform to deliver a variety of biologically active molecules for cancer therapy.

Macrophage inflammatory response to self-assembling rosette nanotubes.

Rosette nanotubes (RNTs) are a new class of nanomaterials with significant therapeutic potential. However, societal concerns related to the potential adverse health effects of engineered nanomaterials drew attention towards the investigation of their interaction with the human U937 macrophage cell line. The cells are treated with medium only (control), lysine (50 microg mL(-1)), lysine-functionalized RNTs (RNT-K; 1, 5, and 50 microg mL(-1)), Min-U-Sil quartz microparticles (80 microg mL(-1)), or lipopolysaccharide (1 microg mL(-1)). The supernatant and cells are assayed for cell viability, cytokine protein, and mRNA expression at 1, 6, and 24 h post-treatment. The results indicate that RNT-K activate transcription of proinflammatory genes (interleukin-8 and tumor necrosis factor-alpha (TNF-alpha)) within 1 h, but this effect is not accompanied by protein secretion into the supernatant. The effect of the length of RNTs on human U937 macrophage viability is also investigated. Although both short and long RNT-K exhibit time-dependent effects on TNF-alpha transcription, only the short RNT-K (5 microg mL(-1)) increase TNF-alpha concentration at 6 h relative to the long RNT-K. Moreover, RNT-K (1 and 5 microg mL(-1)) have no effect on cell viability by 24 h. These data indicate that RNT-K do not induce a robust inflammatory response or cytotoxicity in the U937 human macrophage cell line, and therefore could be used for biomedical applications.