Dengue virus infection induces selective expansion of Vγ4 and Vγ6TCR γδ T cells in the small intestine and a cytokine storm driving vascular leakage in mice

Dengue is a major health problem in tropical and subtropical regions. Some patients develop a severe form of dengue, called dengue hemorrhagic fever, which can be fatal. Severe dengue is associated with a transient increase in vascular permeability. A cytokine storm is thought to be the cause of the vascular leakage. Although there are various research reports on the pathogenic mechanism, the complete pathological process remains poorly understood. We previously reported that dengue virus (DENV) type 3 P12/08 strain caused a lethal systemic infection and severe vascular leakage in interferon (IFN)-α/β and γ receptor knockout mice (IFN-α/β/γRKO mice), and that blockade of TNF-α signaling protected mice. Here, we performed transcriptome analysis of liver and small intestine samples collected chronologically from P12/08-infected IFN-α/β/γRKO mice in the presence/absence of blockade of TNF-α signaling and evaluated the cytokine and effector-level events. Blockade of TNF-α signaling mainly protected the small intestine but not the liver. Infection induced the selective expansion of IL-17A-producing Vγ4 and Vγ6 T cell receptor (TCR) γδ T cells in the small intestine, and IL-17A, together with TNF-α, played a critical role in the transition to severe disease via the induction of inflammatory cytokines such as TNF-α, IL-1β, and particularly the excess production of IL-6. Infection also induced the infiltration of neutrophils, as well as neutrophil collagenase/matrix metalloprotease 8 production. Blockade of IL-17A signaling reduced mortality and suppressed the expression of most of these cytokines, including TNF-α, indicating that IL-17A and TNF-α synergistically enhance cytokine expression. Blockade of IL-17A prevented nuclear translocation of NF-κB p65 in stroma-like cells and epithelial cells in the small intestine but only partially prevented recruitment of immune cells to the small intestine. This study provides an overall picture of the pathogenesis of infection in individual mice at the cytokine and effector levels.

Computer model of IL-6-dependent rheumatoid arthritis in F759 mice

The interleukin-6 (IL-6) amplifier, which describes the simultaneous activation of signal transducer and activator of transcription 3 (STAT3) and NF-κb nuclear factor kappa B (NF-κB), in synovial fibroblasts causes the infiltration of immune cells into the joints of F759 mice. The result is a disease that resembles human rheumatoid arthritis. However, the kinetics and regulatory mechanisms of how augmented transcriptional activation by STAT3 and NF-κB leads to F759 arthritis is unknown. We here show that the STAT3-NF-κB complex is present in the cytoplasm and nucleus and accumulates around NF-κB binding sites of the IL-6 promoter region and established a computer model that shows IL-6 and IL-17 (interleukin 17) signaling promotes the formation of the STAT3-NF-κB complex followed by its binding on promoter regions of NF-κB target genes to accelerate inflammatory responses, including the production of IL-6, epiregulin, and C-C motif chemokine ligand 2 (CCL2), phenotypes consistent with in vitro experiments. The binding also promoted cell growth in the synovium and the recruitment of T helper 17 (Th17) cells and macrophages in the joints. Anti-IL-6 blocking antibody treatment inhibited inflammatory responses even at the late phase, but anti-IL-17 and anti-TNFα antibodies did not. However, anti-IL-17 antibody at the early phase showed inhibitory effects, suggesting that the IL-6 amplifier is dependent on IL-6 and IL-17 stimulation at the early phase, but only on IL-6 at the late phase. These findings demonstrate the molecular mechanism of F759 arthritis can be recapitulated in silico and identify a possible therapeutic strategy for IL-6 amplifier-dependent chronic inflammatory diseases.

GM-CSF Promotes the Survival of Peripheral-Derived Myeloid Cells in the Central Nervous System for Pain-Induced Relapse of Neuroinflammation

We recently discovered a (to our knowledge) new neuroimmune interaction named the gateway reflex, in which the activation of specific neural circuits establishes immune cell gateways at specific vessel sites in organs, leading to the development of tissue-specific autoimmune diseases, including a multiple sclerosis (MS) mouse model, experimental autoimmune encephalomyelitis (EAE). We have reported that peripheral-derived myeloid cells, which are CD11b+MHC class II+ and accumulate in the fifth lumbar (L5) cord during the onset of a transfer model of EAE (tEAE), play a role in the pain-mediated relapse via the pain-gateway reflex. In this study, we investigated how these cells survive during the remission phase to cause the relapse. We show that peripheral-derived myeloid cells accumulated in the L5 cord after tEAE induction and survive more than other immune cells. These myeloid cells, which highly expressed GM-CSFRα with common β chain molecules, grew in number and expressed more Bcl-xL after GM-CSF treatment but decreased in number by blockade of the GM-CSF pathway, which suppressed pain-mediated relapse of neuroinflammation. Therefore, GM-CSF is a survival factor for these cells. Moreover, these cells were colocalized with blood endothelial cells (BECs) around the L5 cord, and BECs expressed a high level of GM-CSF. Thus, GM-CSF from BECs may have an important role in the pain-mediated tEAE relapse caused by peripheral-derived myeloid cells in the CNS. Finally, we found that blockade of the GM-CSF pathway after pain induction suppressed EAE development. Therefore, GM-CSF suppression is a possible therapeutic approach in inflammatory CNS diseases with relapse, such as MS.

Effects of a High-Protein Diet on Kidney Injury under Conditions of Non-CKD or CKD in Mice

Considering the prevalence of obesity and global aging, the consumption of a high-protein diet (HPD) may be advantageous. However, an HPD aggravates kidney dysfunction in patients with chronic kidney disease (CKD). Moreover, the effects of an HPD on kidney function in healthy individuals are controversial. In this study, we employed a remnant kidney mouse model as a CKD model and aimed to evaluate the effects of an HPD on kidney injury under conditions of non-CKD and CKD. Mice were divided into four groups: a sham surgery (sham) + normal diet (ND) group, a sham + HPD group, a 5/6 nephrectomy (Nx) + ND group and a 5/6 Nx + HPD group. Blood pressure, kidney function and kidney tissue injury were compared after 12 weeks of diet loading among the four groups. The 5/6 Nx groups displayed blood pressure elevation, kidney function decline, glomerular injury and tubular injury compared with the sham groups. Furthermore, an HPD exacerbated glomerular injury only in the 5/6 Nx group; however, an HPD did not cause kidney injury in the sham group. Clinical application of these results suggests that patients with CKD should follow a protein-restricted diet to prevent the exacerbation of kidney injury, while healthy individuals can maintain an HPD without worrying about the adverse effects.

Lunar gravity prevents skeletal muscle atrophy but not myofiber type shift in mice

Skeletal muscle is sensitive to gravitational alterations. We recently developed a multiple artificial-gravity research system (MARS), which can generate gravity ranging from microgravity to Earth gravity (1 g) in space. Using the MARS, we studied the effects of three different gravitational levels (microgravity, lunar gravity [1/6 g], and 1 g) on the skeletal muscle mass and myofiber constitution in mice. All mice survived and returned to Earth, and skeletal muscle was collected two days after landing. We observed that microgravity-induced soleus muscle atrophy was prevented by lunar gravity. However, lunar gravity failed to prevent the slow-to-fast myofiber transition in the soleus muscle in space. These results suggest that lunar gravity is enough to maintain proteostasis, but a greater gravitational force is required to prevent the myofiber type transition. Our study proposes that different gravitational thresholds may be required for skeletal muscle adaptation.

Clinical impact of left ventricular systolic dysfunction in patients undergoing dialysis access surgery

BACKGROUND

An arteriovenous fistula (AVF) is the most frequently used dialysis access for haemodialysis. However, it can cause volume loading for the heart and may induce circulatory failure when performed in patients with low cardiac function. This study aimed to characterise patients with low cardiac function when initiating dialysis and determine how cardiac function changes after the dialysis access surgery.

METHODS

We conducted a retrospective observational study at two centres incorporating 356 patients with end-stage kidney disease who underwent echocardiography before the dialysis access surgery.

RESULTS

An AVF and a subcutaneously fixed superficial artery were selected in 70.4% and 23.5% of 81 patients with reduced/mildly reduced (< 50%) left ventricular ejection fraction (LVEF), respectively, and in 94.2% and 1.1% of 275 patients with preserved (≥ 50%) LVEF (p < 0.001), respectively. Follow-up echocardiography was performed in 70.4% and 38.2% of patients with reduced/mildly reduced and preserved LVEF, respectively, which showed a significant increase in LVEF (41 ± 9-44 ± 12%, p = 0.038) in patients with reduced/mildly reduced LVEF. LVEF remained unchanged in 12 patients with reduced/mildly reduced LVEF who underwent subcutaneously fixed superficial artery (30 ± 10-32 ± 15%, p = 0.527). Patients with reduced/mildly reduced LVEF had lower survival rates after surgery than those with preserved LVEF (p = 0.021 for log-rank).

CONCLUSION

The LVEF subcategory was associated with dialysis access selection. After the dialysis access surgery, LVEF was increased in patients with reduced/mildly reduced LVEF. These results may help select dialysis access for patients initiating dialysis.

High-Intensity Interval Training Versus Moderate Continuous Training in Patients With Heart Failure With Preserved Ejection Fraction: A Systematic Review and Meta-analysis

High-intensity interval training (HIIT) is a novel training approach that improves cardiopulmonary fitness and functional capacity in numerous chronic conditions, however its impact in patients with heart failure (HF) with preserved ejection fraction (HFpEF) is uncertain. We evaluated data from prior studies reporting the effects of HIIT versus moderate continuous training (MCT), on cardiopulmonary exercise outcomes in patients with HFpEF. PubMed and SCOPUS were queried from inception till February 1st, 2022 for all randomized controlled trials (RCT) comparing the effect of HIIT versus MCT in patients with HFpEF on peak oxygen consumption (peak VO₂), left atrial volume index (LAVI), respiratory exchange ratio (RER), and ventilatory efficiency (VE/CO₂ slope). A random-effects model was applied, and the weighted mean difference (WMD) of each outcome was reported with 95% confidence intervals (CI). Three RCTs (total N = 150 patients with HFpEF), with a follow-up of 4 to 52 weeks were included in our analysis. Our pooled analysis demonstrated that HIIT significantly improved peak VO₂ (WMD = 1.46 mL/kg/min (0.88, 2.05); P < 0.00001; I² = 0%), as compared to MCT. However, no statistically significant change was demonstrated for LAVI (WMD = -1.71 mL/m² (-5.58, 2.17); P = 0.39; I² = 22%), RER (WMD = -0.10 (-0.32, 0.12); P = 0.38; I² = 0%), and VE/CO₂ slope (WMD = 0.62 (-1.99, 3.24); P = 0.64; I² = 67%) in patients with HFpEF. Across current RCT data, HIIT, compared to MCT, had a significant impact on improving peak VO₂. Conversely, there was no significant change in LAVI, RER, and VE/CO₂ slope between HFpEF patients undertaking HIIT as opposed to MCT.

Impact of Diabetes and Hypertension on Left Ventricular Structure and Function: The Jackson Heart Study

Background Diabetes and hypertension have been associated with adverse left ventricular (LV) remodeling. While they often occur concurrently, their individual effects are understudied. We aimed to assess the independent effects of diabetes and hypertension on LV remodeling in Black adults. Methods and Results The JHS (Jackson Heart Study) participants (n=4143 Black adults) with echocardiographic measures from baseline exam were stratified into 4 groups: neither diabetes nor hypertension (n=1643), only diabetes (n=152), only hypertension (n=1669), or both diabetes and hypertension (n=679). Echocardiographic measures of LV structure and function among these groups were evaluated by multivariable regression adjusting for covariates. Mean age of the participants was 52±1 years, and 63.7% were women. LV mass index was not different in participants with only diabetes compared with participants with neither diabetes nor hypertension (P=0.8). LV mass index was 7.9% (6.0 g/m2) higher in participants with only hypertension and 10.8% (8.1 g/m2) higher in participants with both diabetes and hypertension compared with those with neither (P<0.001). LV wall thickness (relative, posterior, and septal) and brain natriuretic peptide levels in participants with only diabetes were not significantly higher than participants with neither (P>0.05). However, participants with both diabetes and hypertension demonstrated higher LV wall thickness and brain natriuretic peptide levels than participants with neither (P<0.05). Conclusions In this cross-sectional analysis, diabetes was not associated with altered LV structure or function in Black adults unless participants also had hypertension. Our findings suggest hypertension is the main contributor to cardiac structural and functional changes in Black adults with diabetes.

Abstract P439: Ideal Physical Activity is Associated With Reduced Risk of Atrial Fibrillation in African Americans Without Baseline Cardiovascular Disease: The Jackson Heart Study

Background: The effect of physical activity (PA) on incidence of atrial fibrillation (AF) is unclear in African Americans (AA). This study aimed to determine if higher levels of PA are associated with decreased incidence of AF in the Jackson Heart Study (JHS).

Methods: Participants of the JHS with PA assessment and without previous AF at baseline were included in the study. PA was categorized based on the American Heart Association physical activity levels. Incident AF was defined as having 12 lead electrocardiogram evidence at a subsequent follow up, or a documented diagnosis code at the time of hospital discharge from 2000 to 2016. Cox proportional hazards models were used to evaluate for the association between baseline PA and incidence of AF. Given significant correlation between PA and baseline cardiovascular disease (CVD), stratified analysis was performed based on CVD status.

Results: Of the 4,477 participants followed for a median of 12.5 years, 398 developed AF (7.13 cases per 1,000 person-years). Ideal and intermediate PA were associated with a reduced risk of incident AF compared with poor PA (unadjusted HRs with 95% CIs 0.47 [0.34 - 0.64] and 0.72 [0.58 - 0.90], respectively) (Table). After adjustment for traditional cardiovascular risk factors, the associations attenuated and became no longer significant (0.73 [0.53 - 1.00] and 1.00 [0.80 - 1.25], respectively). In stratified analysis based on baseline CVD status, in participants without baseline CVD, ideal PA was significantly associated with a reduced risk of AF while intermediate PA was not (0.68 [0.47 - 0.98] and 1.00 [0.78-1.29], respectively). In participants with baseline CVD, ideal PA or intermediate PA was not associated with incident AF.

Conclusion: Ideal PA was associated with a reduced risk of AF in participants without baseline CVD in this AA community cohort. Our findings show intertwined relationship among PA, CVD, and incident AF. Physical activity could be a possible therapeutic target to reduce AF incidence in the AA general population without CVD.

Vitamin D Levels in Black Americans and the Association With Left Ventricular Remodeling and Incident Heart Failure With Preserved Ejectin Fraction: The Jackson Heart Study

BACKGROUND

In observational studies, a lower serum vitamin D₃ concentration has been associated with an increased risk of cardiovascular disease. However, the associations between serum vitamin D₃ levels and left ventricular (LV) structure and heart failure with preserved ejection fraction (HFpEF) have not been well-characterized among Black Americans. The prevalence of vitamin D₃ deficiency is higher among Black Americans than in other race/ethnicity groups. We hypothesized that serum vitamin D₃ levels are associated with LV concentric remodeling and incident HFpEF in Black Americans.

METHODS AND RESULTS

Among 5306 Black Americans in the Jackson Heart Study cohort, we investigated the relationships between serum vitamin D₃ levels and LV structure and function, evaluated with echocardiography, and incident HF hospitalization, categorized as either HF with reduced EF (HFrEF; an EF of <50%) or HFpEF (an EF of ≥50%). After adjustment for possible confounding factors, lower vitamin D₃ levels were associated with greater relative wall thickness (β for 1 standard deviation [SD] increase -0.003, 95% confidence interval -0.005 to -0.000). Over a median follow-up period of 11 years (range 10.2-11.0 years), 340 participants developed incident HF (7.88 cases per 1000 person-years), including 146 (43%) HFrEF and 194 (57%) HFpEF cases. After adjustment, higher serum vitamin D₃ levels were associated with decreased hazard for HF overall (hazard ratio for 1 SD increase 0.88, 95% confidence interval 0.78-0.99) driven by a significant association with HFpEF (hazard ratio for 1 SD increase 0.84, 95% confidence interval 0.71-0.99).

CONCLUSIONS

In this community-based Black American cohort, lower serum vitamin D₃ levels were associated with LV concentric remodeling and an increased hazard for HF, mainly HFpEF. Further investigation is required to examine whether supplementation with vitamin D₃ can prevent LV concentric remodeling and incident HFpEF in Black Americans.

Changes in metabolism and vestibular function depend on gravitational load in mice

The vestibular system is known to participate in controlling posture and metabolism. Different gravitational environments, including microgravity or hypergravity, cause plastic alteration of the vestibular system, and plasticity is important for adaptation to a novel gravitational environment. However, it is unclear whether the degree of change in vestibular-related physiological function depends on gravitational loading. To examine this, we used a hypergravity environment including 1.33 G, 1.67 G, and 2 G for 29 days. We found that a gravitational threshold induces physiological changes, including vestibular-related posture control and metabolism in mice. Body mass did not return to the preloading level in 1.67 G and 2 G mice. A significant drop in food intake, observed on the first day of hypergravity load, disappeared in all mice after longer exposure. However, a reduction in water intake was sustained in 2 G mice but not 1.33 G and 1.67 G mice. Body temperature did not return to the preloading level in 2 G mice by the final day. A decrease in the skill of the righting reflex was observed in 2 G mice but not 1.33 G and 1.67 G mice. In conclusion, this study showed that hypergravity-induced changes in metabolism and vestibular function depended on the amount of gravitational loading. The 2 G load affected vestibular-related posture control and metabolism considerably, compared with 1.33 G and 1.67 G loads.NEW & NOTEWORTHY It is unclear whether the degree of change in vestibular-related physiological function depends on gravitational loading. Present study showed that exposure to hypergravity-induced degrees of change in metabolism and vestibular function depended on the gravitational loading. The response of body mass depended on the gravitational loading size. Especially in 2 G environment, water intake, body temperature, and vestibular function were influenced. These changes could involve plastic alteration of vestibular-related autonomic and motor functions.

ATP spreads inflammation to other limbs through crosstalk between sensory neurons and interneurons

Neural circuits between lesions are one mechanism through which local inflammation spreads to remote positions. Here, we show the inflammatory signal on one side of the joint is spread to the other side via sensory neuron-interneuron crosstalk, with ATP at the core. Surgical ablation or pharmacological inhibition of this neural pathway prevented inflammation development on the other side. Mechanistic analysis showed that ATP serves as both a neurotransmitter and an inflammation enhancer, thus acting as an intermediary between the local inflammation and neural pathway that induces inflammation on the other side. These results suggest blockade of this neural pathway, which is named the remote inflammation gateway reflex, may have therapeutic value for inflammatory diseases, particularly those, such as rheumatoid arthritis, in which inflammation spreads to remote positions.

Hypertensive Diseases in Pregnancy and Kidney Function Later in Life: The Genetic Epidemiology Network of Arteriopathy (GENOA) Study

OBJECTIVE

To evaluate the relationship between hypertensive diseases in pregnancy and kidney function later in life.

METHODS

We evaluated measured glomerular filtration rate (mGFR) using iothalamate urinary clearance in 725 women of the Genetic Epidemiology Network of Arteriopathy (GENOA) study. Women were classified by self-report as nulliparous (n=62), a history of normotensive pregnancies (n=544), a history of hypertensive pregnancies (n=102), or a history of pre-eclampsia (n=17). We compared adjusted associations among these four groups with mGFR using generalized estimating equations to account for familial clustering. Chronic kidney disease (CKD) was defined as mGFR of less than 60 mL/min per 1.73 m² or urinary albumin-creatinine ratio (UACR) greater than or equal to 30 mg/g.

RESULTS

Among women with kidney function measurements (mean age, 59±9 years, 52.9% African American), those with a history of hypertensive pregnancy had lower mGFR (-4.66 ml/min per 1.73 m²; 95% CI, -9.12 to -0.20) compared with women with a history of normotensive pregnancies. Compared with women with a history of normotensive pregnancies, women with a history of hypertensive pregnancy also had higher odds of mGFR less than 60 ml/min per 1.73 m² (odds ratio, 2.09; 95% CI, 1.21 to 3.60). Additionally, women with a history of hypertensive pregnancy had greater odds for chronic kidney disease (odds ratio, 4.89; 95% CI, 1.55 to 15.44), after adjusting for age, race, education, smoking history, hypertension, body mass index, and diabetes.

CONCLUSION

A history of hypertension in pregnancy is an important prognostic risk factor for kidney disease. To our knowledge, this is the first and largest investigation showing the association between hypertensive diseases in pregnancy and subsequent kidney disease using mGFR in a large biracial cohort.

Bidirectional communication between neural and immune systems

The immune and nervous systems share many features, including receptor and ligand expression, enabling efficient communication between the two. Accumulating evidence suggests that the communication is bidirectional, with the neural system regulating immune cell functions and vice versa. Steroid hormones from the hypothalamus-pituitary-adrenal gland axis are examples of systemic regulators for this communication. Neural reflexes describe regional regulation mechanisms that are a historically new concept that helps to explain how the neural and body systems including immune system communicate. Several recently identified neural reflexes, including the inflammatory reflex and gateway reflex, significantly impact the activation status of the immune system and are associated with inflammatory diseases and disorders. Either pro-inflammatory or anti-inflammatory effects can be elicited by these neural reflexes. On the other hand, the activities of immune cells during inflammation, for example the secretion of inflammatory mediators, can affect the functions of neuronal systems via neural reflexes and modulate biological outputs via specific neural pathways. In this review article, we discuss recent advances in the understanding of bidirectional neuro-immune interactions, with a particular focus on neural reflexes.

Tissue-specific expression of the SARS-CoV-2 receptor, angiotensin-converting enzyme 2, in mouse models of chronic kidney disease

Elevated angiotensin-converting enzyme 2 (ACE2) expression in organs that are potential targets of severe acute respiratory syndrome coronavirus 2 may increase the risk of coronavirus disease 2019 (COVID-19) infection. Previous reports show that ACE2 alter its tissue-specific expression patterns under various pathological conditions, including renal diseases. Here, we examined changes in pulmonary ACE2 expression in two mouse chronic kidney disease (CKD) models: adenine-induced (adenine mice) and aristolochic acid-induced (AA mice). We also investigated changes in pulmonary ACE2 expression due to renin-angiotensin system (RAS) blocker (olmesartan) treatment in these mice. Adenine mice showed significant renal functional decline and elevated blood pressure, compared with controls. AA mice also showed significant renal functional decline, compared with vehicles; blood pressure did not differ between groups. Renal ACE2 expression was significantly reduced in adenine mice and AA mice; pulmonary expression was unaffected. Olmesartan attenuated urinary albumin excretion in adenine mice, but did not affect renal or pulmonary ACE2 expression levels. The results suggest that the risk of COVID-19 infection may not be elevated in patients with CKD because of their stable pulmonary ACE2 expression. Moreover, RAS blockers can be used safely in treatment of COVID-19 patients with CKD.

Abstract 052: Hypertensive Diseases In Pregnancy And Hemodynamic Stress Later In Life

Background: Hypertensive diseases in pregnancy have been associated with cardiovascular diseases later in life. However, less is known about the relationship between hypertensive diseases in pregnancy and hemodynamic stress later in life. We evaluated the relationship between hypertensive diseases in pregnancy and plasma levels of biomarkers of hemodynamic stress later in life in the Genetic Epidemiology Network of Arteriopathy (GENOA) study.

Methods and Results: We investigated 1605 women from the GENOA study (mean age 61±10 years, 57.1% African American).Women were classified as self-reported as nulliparous women (n=140), a history of normotensive pregnancies (n=1,195), a history of a hypertensive pregnancy (n= 229), or a history of preeclampsia (n= 41). We compared adjusted associations among this groups with 4 biomarkers of hemodynamic stress using generalized estimating equations to account for familial clustering. After adjusting for age, race, level of education, smoking history, hypertension, body mass index (BMI), history of coronary artery disease, and diabetes, women with a history of preeclampsia had higher levels of C-terminal proendothelin (CT-proET) compared to women with a history of normotensive pregnancies (Table, p=0.01). There were no significant differences in the levels of midregional proatrial natriuretic peptide (MR-proANP), midregional proadrenomedullin (MR-proADM), and C-Terminal proarginine vasopressin (CT-proAVP) in this groups.

Conclusions: Elevated levels of CT-proET (a precursor to the potent vasoconstrictor Endothelin 1) demonstrates a strong relationship among those with a history of preeclampsia. Future studies are warranted to further explore the relationship between CT-proET in the pathogenesis of preeclampsia as well as subsequent changes in cardiovascular structure and function associated with a history of preeclampsia later in life.

Rhodobacter azotoformans LPS (RAP99-LPS) Is a TLR4 Agonist That Inhibits Lung Metastasis and Enhances TLR3-Mediated Chemokine Expression

The lipopolysaccharides (LPSs) of Rhodobacter are reported to be TLR4 antagonists. Accordingly, the extract of Rhodobacter azotoformans (RAP99) is used as a health supplement for humans and animals in Japan to regulate immune responses in vivo. We previously analyzed the LPS structure of RAP99 (RAP99-LPS) and found it is different from that of E. coli-LPS but similar to lipid A from Rhodobacter sphaeroides (RSLA), a known antagonist of TLR4, with both having three C14 fatty acyl groups, two C10 fatty acyl groups, and two phosphates. Here we show that RAP99-LPS has an immune stimulatory activity and acts as a TLR4 agonist. Pretreatment of RAP99-LPS suppressed E. coli-LPS-mediated weight loss, suggesting it is an antagonist against E. coli-LPS like other LPS isolated from Rhodobacter. However, injections of RAP99-LPS caused splenomegaly and increased immune cell numbers in C57BL/6 mice but not in C3H/HeJ mice, suggesting that RAP99-LPS stimulates immune cells via TLR4. Consistently, RAP99-LPS suppressed the lung metastasis of B16F1 tumor cells and enhanced the expression of TLR3-mediated chemokines. These results suggest that RAP99-LPS is a TLR4 agonist that enhances the activation status of the immune system to promote anti-viral and anti-tumor activity in vivo.

Sjögren's syndrome-associated SNPs increase GTF2I expression in salivary gland cells to enhance inflammation development

Sjögren's syndrome (SS) is an autoimmune disease characterized by inflammation with lymphoid infiltration and destruction of the salivary glands. Although many genome-wide association studies have revealed disease-associated risk alleles, the functions of the majority of these alleles are unclear. Here, we show previously unrecognized roles of GTF2I molecules by using two SS-associated single nucleotide polymorphisms (SNPs), rs73366469 and rs117026326 (GTF2I SNPs). We found that the risk alleles of GTF2I SNPs increased GTF2I expression and enhanced nuclear factor-kappa B (NF-κB) activation in human salivary gland cells via the NF-κB p65 subunit. Indeed, the knockdown of GTF2I suppressed inflammatory responses in mouse endothelial cells and in vivo. Conversely, the over-expression of GTF2I enhanced NF-κB reporter activity depending on its p65-binding N-terminal leucine zipper domain. GTF2I is highly expressed in the human salivary gland cells of SS patients expressing the risk alleles. Consistently, the risk alleles of GTF2I SNPs were strongly associated with activation of the IL-6 amplifier, which is hyperactivation machinery of the NF-κB pathway, and lymphoid infiltration in the salivary glands of SS patients. These results demonstrated that GTF2I expression in salivary glands is increased in the presence of the risk alleles of GTF2I SNPs, resulting in activation of the NF-κB pathway in salivary gland cells. They also suggest that GTF2I could be a new therapeutic target for SS.

Physical Activity, Inflammation, Coronary Artery Calcification, and Incident Coronary Heart Disease in African Americans: Insights From the Jackson Heart Study

OBJECTIVE

To examine associations between physical activity (PA), inflammation, coronary artery calcification (CAC), and incident coronary heart disease (CHD) in African Americans.

METHODS

Among Jackson Heart Study participants without prevalent CHD at baseline (n=4295), we examined the relationships between PA and high-sensitivity C-reactive protein, the presence of CAC (Agatston score ≥100), and incident CHD. Based on the American Heart Association's Life's Simple 7 metrics, participants were classified as having poor, intermediate, or ideal PA.

RESULTS

After adjustment for possible confounding factors, ideal PA was associated with lower high-sensitivity C-reactive protein levels (β, -0.15; 95% CI, -0.15 to -0.002) and a lower prevalence of CAC (odds ratio, 0.70; 95% CI, 0.51-0.96) compared with poor PA. During a median of 12.8 years of follow-up, there were 164 incident CHD events (3.3/1000 person-years). Ideal PA was associated with a lower rate of incident CHD compared with poor PA (hazard ratio, 0.55; 95% CI, 0.31-0.98).

CONCLUSION

In a large community-based African American cohort, ideal PA was associated with lower inflammation levels, a lower prevalence of CAC, and a lower rate of incident CHD. These findings suggest that promotion of ideal PA may be an important way to reduce the risk of subclinical and future clinical CHD in African Americans.

Cigarette Smoking, Incident Coronary Heart Disease, and Coronary Artery Calcification in Black Adults: The Jackson Heart Study

Background

Although Black adults are more likely to die from coronary heart disease (CHD) compared with White adults, few studies have examined the relationship between cigarette smoking and CHD risk among Black adults. We evaluated the relationship between cigarette smoking, incident CHD, and coronary artery calcification in the JHS (Jackson Heart Study).

Methods and Results

We classified JHS participants without a history of CHD (n=4432) by self‐reported baseline smoking status into current, former (smoked at least 400 cigarettes/life) or never smokers at baseline (2000–2004). We further classified current smokers by smoking intensity (number of cigarettes smoked per day [1–19 or ≥20]) and followed for incident CHD (through 2016). Hazard ratios (HR) for incident CHD for each smoking group compared with never smokers were estimated with adjusted Cox proportional hazard regression models. At baseline, there were 548 (12.4%) current, 782 (17.6%) former, and 3102 (70%) never smokers. During follow‐up (median, 13.8 years), 254 participants developed CHD. After risk factor adjustment, CHD risk was significantly higher in current smokers compared with never smokers (HR, 2.11; 95% CI, 1.39–3.18); the difference between former smokers and never smokers (HR, 1.37; 95% CI, 1.0–1.90) did not achieve statistical significance. Among current smokers, we did not observe a dose‐response effect for CHD risk. Additionally, in multivariable logistic regression models with a subset of our analytic cohort, current smokers had greater odds of coronary artery calcification score >0 compared with never smokers (odds ratio, 2.63; 95% CI, 1.88–3.68).

Conclusions

In a large prospective cohort of Black adults, current smoking was associated with a >2‐fold increased risk of CHD over a median follow‐up of greater than a decade.

Orosomucoid 1 is involved in the development of chronic allograft rejection after kidney transplantation

Chronic allograft rejection is the most common cause of long-term allograft failure. One reason is that current diagnostics and therapeutics for chronic allograft rejection are very limited. We here show that enhanced NFκB signaling in kidney grafts contributes to chronic active antibody-mediated rejection (CAAMR), which is a major pathology of chronic kidney allograft rejections. Moreover, we found that urinary orosomucoid 1 (ORM1) is a candidate marker molecule and therapeutic target for CAAMR. Indeed, urinary ORM1 concentration was significantly higher in kidney transplant recipients pathologically diagnosed with CAAMR than in kidney transplant recipients with normal histology, calcineurin inhibitor toxicity, or interstitial fibrosis and tubular atrophy. Additionally, we found that kidney biopsy samples with CAAMR expressed more ORM1 and had higher NFκB and STAT3 activation in tubular cells than samples from non-CAAMR samples. Consistently, ORM1 production was induced after cytokine-mediated NFκB and STAT3 activation in primary kidney tubular cells. The loss- and gain-of-function of ORM1 suppressed and promoted NFκB activation, respectively. Finally, ORM1-enhanced NFκB-mediated inflammation development in vivo. These results suggest that an enhanced NFκB-dependent pathway following NFκB and STAT3 activation in the grafts is involved in the development of chronic allograft rejection after kidney transplantation and that ORM1 is a non-invasive candidate biomarker and possible therapeutic target for chronic kidney allograft rejection.

Relation of Low Normal Left Ventricular Ejection Fraction to Heart Failure Hospitalization in Blacks (From the Jackson Heart Study)

There is no clear consensus on a lower cutoff value for normal left ventricular ejection fraction (EF) and the prognostic implications of low normal EF (LNEF) are poorly understood, particularly in Blacks. Therefore, we investigated the association of LNEF and incident heart failure (HF) in a community-based cohort of Blacks. We studied 3,669 participants (mean age 54 years, 63% women) of the Jackson Heart Study without prevalent HF or coronary heart disease (CHD). Participants were divided into three groups: (1) Reduced EF (<50%), (2) LNEF (≥50%, <55%), and (3) Normal EF (≥55%). There were 197 cases of incident HF hospitalizations over a median follow-up of 10 years (interquartile range 9.4 to 10). After adjustment for conventional risk factors and incident CHD, the LNEF group had a higher rate of incident HF hospitalization than the Normal EF group (HR 1.58, 95% CI 1.04 to 2.38, p<0.05). Furthermore, this relation remained statistically significant after additionally adjusting for LV mass index but was not significant after adjusting for LV diastolic dysfunction grade. In participants with LNEF with incident HF, 63% developed HF with reduced EF and 37% developed HF with preserved EF. In conclusion, LNEF is associated with higher risk of incident HF hospitalization in comparison with normal EF in a community-based cohort of Blacks. In those with LNEF who went on to develop HF, most cases were HF with reduced EF. These findings suggest that strategies are needed for risk stratification and management to improve outcomes in patients with LNEF.

Cigarette Smoking and Incident Stroke in Blacks of the Jackson Heart Study

Background Blacks are disproportionately affected by stroke compared with whites; however, less is known about the relationship between stroke and cigarette smoking in blacks. Therefore, we evaluated the relationship between cigarette smoking and all incident stroke in the JHS (Jackson Heart Study). Methods and Results JHS participants without a history of stroke (n=4410) were classified by self-reported baseline smoking status into current, past (smoked at least 400 cigarettes/life), or never smokers at baseline (2000-2004). Current smokers were further classified by smoking intensity (number of cigarettes smoked per day [1-19 and ≥20]) and followed up for incident stroke (through 2015). Hazard ratios (HRs) for incident stroke for current and past smoking compared with never smoking were estimated with adjusted Cox proportional hazard regression models. After adjusting for cardiovascular risk factors, the risk for stroke in current smokers was significantly higher compared with never smokers (HR, 2.48; 95% CI, 1.60-3.83) but there was no significant difference between past smokers and never smokers (HR, 1.10; 95% CI, 0.74-1.64). There was a dose-dependent increased risk of stroke with smoking intensity (HR, 2.28 [95% CI, 1.38-3.86] and HR, 2.78 [95% CI, 1.47-5.28] for current smokers smoking 1-19 and ≥20 cigarettes/day, respectively). Conclusions In a large cohort of blacks, current cigarette smoking was associated with a dose-dependent higher risk of all stroke. In addition, past smokers did not have a significantly increased risk of all stroke compared with never smokers, which suggests that smoking cessation may have potential benefits in reducing the incidence of stroke in blacks.

Increased urinary exosomal SYT17 levels in chronic active antibody-mediated rejection after kidney transplantation via the IL-6 amplifier

Chronic active antibody-mediated rejection (CAAMR) is a particular problem in kidney transplantation (KTx), and ~25% of grafts are lost by CAAMR. Further, the pathogenesis remains unclear, and there is no effective cure or marker. We previously found that a hyper NFκB-activating mechanism in non-immune cells, called the IL-6 amplifier, is induced by the co-activation of NFκB and STAT3, and that this activation can develop various chronic inflammatory diseases. Here, we show that synaptotagmin-17 (SYT17) is increased in an exosomal fraction of the urine from CAAMR patients, and that this increase is associated with activation of the IL-6 amplifier. Immunohistochemistry showed that SYT17 protein expression was increased in renal tubule cells of the CAAMR group. While SYT17 protein was not detectable in whole-urine samples by western blotting, urinary exosomal SYT17 levels were significantly elevated in the CAAMR group compared to three other histology groups (normal, interstitial fibrosis and tubular atrophy, and calcineurin inhibitors toxicity) after KTx. On the other hand, current clinical laboratory data could not differentiate the CAAMR group from these groups. These data suggest that urinary exosomal SYT17 is a potential diagnostic marker for CAAMR.

Role of Chondrocytes in the Development of Rheumatoid Arthritis Via Transmembrane Protein 147-Mediated NF-κB Activation

OBJECTIVE

We have previously reported that the coactivation of NF-κB and STAT3 in nonimmune cells, including synovial fibroblasts, enhances the expression of NF-κB target genes and plays a role in chronic inflammation and rheumatoid arthritis (RA). This study was undertaken to examine the role of NF-κB activation in chondrocytes and better understand the pathogenesis of RA. Furthermore, transmembrane protein 147 (TMEM147) was investigated as a representative NF-κB activator in chondrocytes.

METHODS

Clinical samples from RA patients were analyzed by immunohistochemistry. Specimens obtained from patients with polydactyly were used as control samples. The functional contribution of chondrocytes and TMEM147 to arthritis was examined in several murine models of RA. In vitro experiments (quantitative polymerase chain reaction, RNA interference, immunoprecipitation, and confocal microscopy) were performed to investigate the mechanism of action of TMEM147 in chondrocytes.

RESULTS

Samples obtained from RA patients and mouse models of RA showed coactivation of NF-κB and STAT3 in chondrocytes (P < 0.001). This coactivation induced a synergistic expression of NF-κB targets in vitro (P < 0.01). Chondrocyte-specific deletion of STAT3 significantly suppressed the development of cytokine-induced RA (P < 0.01). TMEM147 was highly expressed in chondrocytes from RA patient samples and the mouse models of RA. Gene silencing of TMEM147 or anti-TMEM147 antibody treatment inhibited the cytokine-mediated activation of NF-κB in vitro (P < 0.01) and suppressed cytokine-induced RA in vivo (P < 0.01). Mechanistically, TMEM147 molecules acted as scaffold proteins for the NF-κB complex, which included breakpoint cluster region and casein kinase 2, and enhanced NF-κB activity.

CONCLUSION

These results suggest that chondrocytes play a role in the development of RA via TMEM147-mediated NF-κB activation and indicate a novel therapeutic strategy for RA.

Effects of Rikkunshito treatment on renal fibrosis/inflammation and body weight reduction in a unilateral ureteral obstruction model in mice

Chronic kidney disease (CKD) progresses to end-stage renal failure via renal tubulointerstitial fibrosis. Malnutrition, inflammation, and arteriosclerosis interact to exacerbate the poor prognosis of CKD, and their effective management is thus essential. The traditional Japanese medicine Rikkunshito (RKT) exerts appetite-stimulating effects via ghrelin, which attenuates inflammation and fibrosis. We evaluated the therapeutic effect of RKT in unilateral ureter obstruction (UUO)-induced renal fibrosis/inflammation and body weight loss in mice. UUO and sham-operated mice were fed a standard diet or diet containing 3.0% RKT. Renal fibrosis was investigated by histopathology and macrophage infiltration was determined by immunohistochemistry. Expression levels of genes associated with fibrosis, inflammation, ghrelin, and mitochondrial function were determined by quantitative reverse transcription-polymerase chain reaction and western blot analyses. RKT treatment partially prevented UUO-induced weight loss but failed to attenuate renal fibrosis and inflammation. Renal expression of sirtuin 1, a ghrelin-downstream signalling molecule, and gene expression of peroxisome proliferator-activated receptor-γ coactivator 1α and Bcl-2/adenovirus E1B interacting protein 3 were unaffected by RKT. These results indicate that RKT inhibits weight loss but does not improve renal fibrosis or inflammation in a rapidly progressive renal fibrosis mouse model. RKT may have a protective effect on weight loss associated with CKD.

Neural stimulations regulate the infiltration of immune cells into the CNS

The systemic regulation of immune reactions by the nervous system is well studied and depends on the release of hormones. Some regional regulations of immune reactions, on the other hand, depend on specific neural pathways. Better understanding of these regulations will expand therapeutic applications for neuroimmune and organ-to-organ functional interactions. Here, we discuss one regional neuroimmune interaction, the gateway reflex, which converts specific neural inputs into local inflammatory outputs in the CNS. Neurotransmitters released by the inputs stimulate specific blood vessels to express chemokines, which serve as a gateway for immune cells to extravasate into the target organ such as the brain or spinal cord. Several types of gateway reflexes have been reported, and each controls distinct CNS blood vessels to form gateways that elicit local inflammation, particularly in the presence of autoreactive immune cells. For example, neural stimulation by gravity creates the initial entry point to the CNS by CNS-reactive pathogenic CD4+ T cells at the dorsal vessels of fifth lumbar spinal cord, while pain opens the gateway at the ventral side of blood vessels in the spinal cord. In addition, it was recently found that local inflammation by the gateway reflex in the brain triggers the activation of otherwise resting neural circuits to dysregulate organ functions in the periphery including the upper gastrointestinal tract and heart. Therefore, the gateway reflex represents a novel bidirectional neuroimmune interaction that regulates organ functions and could be a promising target for bioelectric medicine.

Phosphorylation-dependent Regnase-1 release from endoplasmic reticulum is critical in IL-17 response

The endoribonuclease Regnase-1 suppresses inflammation through RNA degradation. Here, we show that Regnase-1 is phosphorylated and inactivated by the Act1-TBK1-IKKi axis during IL-17 stimulation. Moreover, this phosphorylation substantially contributes to the mRNA stabilization needed for amplification of TH17-cell–mediated inflammation.

Regnase-1 (also known as Zc3h12a or MCPIP-1) is an endoribonuclease involved in mRNA degradation of inflammation-associated genes. Regnase-1 is inactivated in response to external stimuli through post-translational modifications including phosphorylation, yet the precise role of phosphorylation remains unknown. Here, we demonstrate that interleukin (IL)-17 induces phosphorylation of Regnase-1 in an Act1-TBK1/IKKi–dependent manner, especially in nonhematopoietic cells. Phosphorylated Regnase-1 is released from the endoplasmic reticulum (ER) into the cytosol, thereby losing its mRNA degradation function, which leads to expression of IL-17 target genes. By using CRISPR/Cas-9 technology, we generated Regnase-1 mutant mice, in which IL-17–induced Regnase-1 phosphorylation is completely blocked. Mutant mice (Regnase-1^AA/AA and Regnase-1^ΔCTD/ΔCTD) were resistant to the IL-17–mediated inflammation caused by T helper 17 (Th17) cells in vivo. Thus, Regnase-1 plays a critical role in the development of IL-17–mediated inflammatory diseases via the Act1-TBK1-IKKi axis, and blockade of Regnase-1 phosphorylation sites may be promising for treatment of Th17-associated diseases.

Impact of the Temporal Distribution of Coronary Artery Disease Progression on Subsequent Consequences in Patients with Acute Coronary Syndrome

The late consequences of acute coronary syndrome (ACS) have been underestimated. We hypothesized that the temporal distribution of the clinically silent coronary artery disease progression (CP) is associated with the subsequent consequences of ACS.We studied 243 patients (202 men, 64 ± 10 years) with ACS undergoing percutaneous coronary intervention (PCI) during initial hospitalization. All patients underwent serial coronary angiograms (CAGs) immediately before PCI and at 7 ± 3 and 60 ± 10 months after presentation. CP was defined as an increase ≥ 15% in stenosis severity of the lesion between 2 serial CAGs. The impact of CP between each 2 serial CAGs on subsequent major adverse cardiovascular and cerebrovascular events (MACCEs) after the final CAG was examined using multivariate Cox and propensity-matched analyses.During the median follow-up duration after the final CAG of 67 months, 76 MACCEs (31.3%) were observed. Multivariate Cox proportional hazards analysis revealed that CP between the first and second CAGs (hazard ratio [HR], 2.28; 95% confidence interval [CI], 1.32-3.94; P = 0.003) and CP between the second and final CAGs (HR, 1.96; 95% CI, 1.20-3.21; P = 0.008) were independently associated with a higher rate of MACCEs beyond the final CAG. Consistent results were obtained in the propensity score-matched analyses.CP in both the early (0-7 months) and late phases (7-60 months) were independently associated with subsequent clinical events. This may indicate the prognostic significance of persistent widespread coronary disease activity following presentation in patients with ACS undergoing PCI.

Photopic light-mediated down-regulation of local α1A-adrenergic signaling protects blood-retina barrier in experimental autoimmune uveoretinitis

We have reported the gateway reflex, which describes specific neural activations that regulate immune cell gateways at specific blood vessels in the central nervous system (CNS). Four types of gateway reflexes exist, all of which induce alterations in endothelial cells at specific vessels of the blood-brain barrier followed by inflammation in the CNS in the presence of CNS-autoreactive T cells. Here we report a new gateway reflex that suppresses the development of retinal inflammation by using an autoreactive T cell-mediated ocular inflammation model. Exposure to photopic light down-regulated the adrenoceptor pathway to attenuate ocular inflammation by suppressing breaching of the blood-retina barrier. Mechanistic analysis showed that exposure to photopic light down-regulates the expression of α_1A-adrenoceptor (α_1AAR) due to high levels of norepinephrine and epinephrine, subsequently suppressing inflammation. Surgical ablation of the superior cervical ganglion (SCG) did not negate the protective effect of photopic light, suggesting the involvement of retinal noradrenergic neurons rather than sympathetic neurons from the SCG. Blockade of α_1AAR signaling under mesopic light recapitulated the protective effect of photopic light. Thus, targeting regional adrenoceptor signaling might represent a novel therapeutic strategy for autoimmune diseases including those that affect organs separated by barriers such as the CNS and eyes.

Cigarette Smoking and Subclinical Peripheral Arterial Disease in Blacks of the Jackson Heart Study

Background Prevalence of peripheral artery disease ( PAD ) is significantly higher among blacks as compared with non-Hispanic whites, but the role of cigarette smoking in PAD is understudied in blacks. We aimed to evaluate the relationship between cigarette smoking and PAD in blacks in the (JHS) Jackson Heart Study. Methods and Results JHS participants (n=5306) were classified by self-reported baseline smoking status into current, past (smoked at least 400 cigarettes/life), or never smokers. We examined multivariable logistic and robust linear regression models to estimate the associations between baseline smoking status, smoking intensity, and measures of subclinical PAD (ankle-brachial index [visit 1] and aortic calcium by computed tomography [visit 2]) to yield odds ratios and β-coefficients (estimated adjusted difference) to compare each smoking status with never smokers (reference group). There were 3579 (68%) never smokers, 986 (19%) past smokers, and 693 (13%) current smokers self-identified at baseline. After adjustment for covariates, current smokers had increased risk of ankle-brachial index <1 (odds ratio, 2.2, 95% CI, 1.5-3.3) and increased risk of abdominal aortic (odds ratio, 8.4, 95% CI, 5.8-12.0) and aortoiliac calcium (odds ratio, 9.6, 95% CI, 6.7-13.7). When stratifying by smoking intensity, those smoking more than 20 cigarettes daily (1 pack) had higher likelihood of subclinical PAD by all of these measures compared with lower-intensity use, suggesting a dose-dependent relationship. Conclusions In a large black cohort, cigarette smoking was associated with measures of subclinical PAD in a dose-dependent manner. These findings highlight the association between smoking and PAD in blacks and support further research exploring the impact of interventions on smoking cessation to reduce PAD in this population.

Bmi1 Regulates IκBα Degradation via Association with the SCF Complex

Bmi1 is a polycomb group protein and regulator that stabilizes the ubiquitination complex PRC1 in the nucleus with no evidently direct link to the NF-κB pathway. In this study, we report a novel function of Bmi1: its regulation of IκBα ubiquitination in the cytoplasm. A deficiency of Bmi1 inhibited NF-κB-mediated gene expression in vitro and a NF-κB-mediated mouse model of arthritis in vivo. Mechanistic analysis showed that Bmi1 associated with the SCF ubiquitination complex via its N terminus and with phosphorylation by an IKKα/β-dependent pathway, leading to the ubiquitination of IκBα. These effects on NF-κB-related inflammation suggest Bmi1 in the SCF complex is a potential therapeutic target for various diseases and disorders, including autoimmune diseases.

Presenilin 1 Regulates NF-κB Activation via Association with Breakpoint Cluster Region and Casein Kinase II

We recently reported that NF-κB-mediated inflammation caused by breakpoint cluster region (BCR) is dependent on the α subunit of casein kinase II (CK2α) complex. In the current study, we demonstrate that presenilin 1 (Psen1), which is a catalytic component of the γ-secretase complex and the mutations of which are known to cause familial Alzheimer disease, acts as a scaffold of the BCR-CK2α-p65 complex to induce NF-κB activation. Indeed, Psen1 deficiency in mouse endothelial cells showed a significant reduction of NF-κB p65 recruitment to target gene promoters. Conversely, Psen1 overexpression enhanced reporter activation under NF-κB responsive elements and IL-6 promoter. Furthermore, the transcription of NF-κB target genes was not inhibited by a γ-secretase inhibitor, suggesting that Psen1 regulates NF-κB activation in a manner independent of γ-secretase activity. Mechanistically, Psen1 associated with the BCR-CK2α complex, which is required for phosphorylation of p65 at serine 529. Consistently, TNF-α-induced phosphorylation of p65 at serine 529 was significantly decreased in Psen1-deficient cells. The association of the BCR-CK2α-p65 complex was perturbed in the absence of Psen1. These results suggest that Psen1 functions as a scaffold of the BCR-CK2α-p65 complex and that this signaling cascade could be a novel therapeutic target for various chronic inflammation conditions, including those in Alzheimer disease.

Elevated serum osteoprotegerin is associated with increased left ventricular mass index and myocardial stiffness

AIM

Osteoprotegerin (OPG) is associated with a poor prognosis in patients with heart failure with preserved ejection fraction (HFpEF). OPG has also been associated with fibrosis and collagen cross-linking, which increase arterial and left ventricle (LV) myocardial stiffness. Little is known about the relation of OPG and LV structure and function in African-Americans who are disproportionately affected by HFpEF.

METHODS AND RESULTS

Our analysis included 1172 participants with preserved LV ejection fraction (>50%) from the African-American cohort in the Genetic Epidemiology Network of Arteriopathy Study (mean age 63 years, 72% female). We used diastolic wall strain indicator measured by echocardiography to assess LV myocardial stiffness. Diastolic wall strain was calculated as (LV posterior thickness at end-systole - LV posterior thickness at end-diastole)/LV posterior thickness at end-systole. Associations between OPG levels and indices of arterial and LV structure and function were evaluated by using generalized linear mixed models and adjusted for possible confounders. OPG levels were correlated with age, female sex, presence of hypertension and diabetes, and lower estimated glomerular filtration rate (P < 0.05 for all). Multivariable analysis revealed that higher OPG levels were associated with greater LV mass index, increased LV myocardial stiffness, and higher N-terminal prohormone brain natriuretic peptide levels (P < 0.05 for all).

CONCLUSION

In African-Americans, higher OPG levels were associated with characteristics common in patients with HFpEF and were significantly associated with known precursors to HFpEF. These findings indicate a potential role for OPG in the pathophysiology of HFpEF in African-Americans.

Higher plasma leptin levels are associated with reduced left ventricular mass and left ventricular diastolic stiffness in black women: insights from the Genetic Epidemiology Network of Arteriopathy (GENOA) study

Our previous experimental animal data suggest a beneficial effect of leptin on LV structure and function. We hypothesized that leptin levels are associated with lower LV mass and myocardial stiffness which are important risk factors for the development of heart failure with preserved ejection fraction (HFpEF). We evaluated 1172 blacks, in which the prevalence of HFpEF is quite high, with preserved LV ejection fraction (EF > 50%) from the Genetic Epidemiology Network of Arteriopathy Study (mean age 62.9 years, 72% women), a community-based study to identify genes influencing blood pressure and target organ damage due to hypertension. Associations between leptin levels and indices of LV structure and function were evaluated using generalized estimating equations accounting for clustering in siblings. LV myocardial stiffness was evaluated using diastolic wall strain (DWS) measured by echocardiography. Analyses were stratified by sex because leptin levels were three times higher in women than men (p < 0.001). After adjustment for confounders, higher leptin levels were associated with lower LV mass (coefficient for 1 s.d. increase of leptin level: -5.825 g, 95% CI: -9.755 to -1.895 g, P = 0.004) and higher DWS (lower LV stiffness) (coefficient for 1 s.d. increase of leptin level: 0.009, 95% CI: 0.002-0.015, P = 0.007) in women. There were no statistically significant associations in men. In women, there were interactions between leptin levels and body mass index quartiles on LV mass and stiffness (p < 0.05 for both). Higher leptin levels were associated with lower LV mass and stiffness in obese but not lean black women.

Existence of NEU1 sialidase on mouse thymocytes whose natural substrate is CD5

Membrane-bound sialidases in the mouse thymus are unique and mysterious because their activity at pH 6.5 is equal to or higher than that in the acidic region. The pH curve like this has never been reported in membrane-bound form. To clarify this enzyme, we studied the sialidase activities of crude membrane fractions from immature-T, mature-T and non-T cells from C57BL/6 mice and from SM/J mice, a strain with a defect in NEU1 activity. Non-T cells from C57BL/6 mice had high activity at pH 6.5, but those from SM/J mice did not. Neu1 and Neu3 mRNA was shown by real-time PCR to be expressed in T cells and also in non-T cells, whereas Neu2 was expressed mainly in non-T cells and Neu4 was scarcely expressed. However, the in situ hybridization study on the localization of four sialidases in the thymus showed that Neu4 was clearly expressed. We then focused on a sialidase on the thymocyte surface because the possibility of the existence of a sialidase on thymocytes was suggested by peanut agglutinin (PNA) staining after incubation of the cells alone in PBS. This activity was inhibited by NEU1-selective sialidase inhibitor C9-butyl-amide-2-deoxy-2,3-dehydro-N-acetylneuraminic acid. The natural substrate for the cell surface sialidase was identified as clustered differentiation 5 (CD5) by PNA-blot analysis of anti-CD5 immunoprecipitate. We conclude that NEU1 exists on the cell surface of mouse thymocytes and CD5 is a natural substrate for it. Although this is not the main reaction of the membrane-bound thymus-sialidases, it must be important for the thymus.

Cigarette Smoking and Incident Heart Failure: Insights From the Jackson Heart Study

BACKGROUND

Cigarette smoking has been linked with several factors associated with cardiac dysfunction. We hypothesized that cigarette smoking is associated with left ventricular (LV) structure and function, and incident heart failure (HF) hospitalization.

METHODS

We investigated 4129 (never smoker n=2884, current smoker n=503, and former smoker n=742) black participants (mean age, 54 years; 63% women) without a history of HF or coronary heart disease at baseline in the Jackson Heart Study. We examined the relationships between cigarette smoking and LV structure and function by using cardiac magnetic resonance imaging among 1092 participants, cigarette smoking and brain natriuretic peptide levels among 3325 participants, and incident HF hospitalization among 3633 participants with complete data.

RESULTS

After adjustment for confounding factors, current smoking was associated with higher mean LV mass index and lower mean LV circumferential strain (P<0.05, for both) in comparison with never smoking. Smoking status, intensity, and burden were associated with higher mean brain natriuretic peptide levels (all P<0.05). Over 8.0 years (7.7-8.0) median follow-up, there were 147 incident HF hospitalizations. After adjustment for traditional risk factors and incident coronary heart disease, current smoking (hazard ratio, 2.82; 95% confidence interval, 1.71-4.64), smoking intensity among current smokers (≥20 cigarettes/d: hazard ratio, 3.48; 95% confidence interval, 1.65-7.32), and smoking burden among ever smokers (≥15 pack-years: hazard ratio, 2.06; 95% confidence interval, 1.29-3.3) were significantly associated with incident HF hospitalization in comparison with never smoking.

CONCLUSIONS

In blacks, cigarette smoking is an important risk factor for LV hypertrophy, systolic dysfunction, and incident HF hospitalization even after adjusting for effects on coronary heart disease.