Association of cardiac preservation solution with short-term outcomes after heart transplantation.

AIMS: There is wide variability in the practice of cardiac preservation for heart transplantation. Prior reports suggest that the type of solution may be linked with a reduced incidence of posttransplantation complications. METHODS: Adult (≥18 years old) heart recipients who underwent transplantation between 2015 and 2021 in the United States were examined. Recipients were stratified by solution utilized for their grafts at the time of recovery: University of Wisconsin, histidine-tryptophan-ketoglutarate (HTK), or Celsior solution. The primary endpoint was a composite of 30-day mortality, primary graft dysfunction, or re-transplantation. Risk adjustment was performed for the recipient, donor, and procedural characteristics using regression modeling. RESULTS: Among 16 884 recipients, the group distribution was University of Wisconsin solution 53%, HTK 22%, Celsior solution 15%, and other 10%. The observed incidence of the composite endpoint (University of Wisconsin solution = 3.6%, HTK = 4.0%, Celsior solution = 3.7%, P = 0.301) and 1-year survival (University of Wisconsin solution = 91.7%, HTK = 91.3%, Celsior solution = 91.7%, log-rank P = 0.777) were similar between groups. After adjustment, HTK was associated with a higher risk of the composite endpoint [odds ratio (OR) 1.249, 95% confidence interval (CI) 1.019-1.525, P = 0.030] in reference to University of Wisconsin solution. This association was substantially increased among recipients with ischemic periods of greater than 4 h (OR 1.817, 95% CI 1.188-2.730, P = 0.005). The risks were similar between University of Wisconsin solution and Celsior solution (P = 0.454). CONCLUSION: The use of the histidine-tryptophan-ketoglutarate solution during cold static storage for cardiac preservation is associated with increased rates of early mortality or primary graft dysfunction. Clinician discretion should guide its use, especially when prolonged ischemic times (>4 h) are anticipated.

Aging exacerbates cardiac dysfunction and mortality in sepsis through enhancing TLR2 activity.

Introduction: Sepsis is prevalent in the elderly population with increased incidence and mortality. Currently, the mechanism by which aging increases the susceptibility to sepsis and worsens outcome is unclear. We tested the hypothesis that aging exacerbates cardiac dysfunction in sepsis through a Toll-like receptor 2 (TLR2)-dependent mechanism. Methods: Male young adult (4-6 months) and old (18-20 months) wild type (WT) and TLR2 knockout (KO) mice were subject to moderate sepsis by cecal ligation and puncture. Additional groups of young adult and old WT mice were treated with TLR2 agonist Pam3CSK4. Left ventricle (LV) performance was evaluated with a pressure-volume microcatheter. Tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in the myocardium and plasma were assessed using enzyme-linked immunosorbent assay. Results: Sepsis reduced LV ejection fraction and cardiac output in both young adult and old WT mice. However, identical CLP caused more severe cardiac dysfunction and high mortality in old WT mice that were accompanied by greater levels of TNF-α, IL-1ß, IL-6 and MCP-1 in the myocardium and plasma. TLR2 KO diminished aging-related difference in myocardial and systemic inflammatory response, resulting in improved cardiac function and decreased mortality in old septic mice. In addition, higher myocardial TLR2 levels in old WT mice resulted in greater myocardial inflammatory response and worse cardiac dysfunction following administration of TLR2 agonist. Conclusion: Moderate sepsis results in greater cardiac dysfunction and significant mortality in old mice. Aging elevates TLR2 level/activity to exacerbate the inflammatory response to sepsis, leading to worse cardiac dysfunction and mortality.

Recombinant IL-37 Exerts an Anti-inflammatory Effect on Human Aortic Valve Interstitial Cells through Extracellular and Intracellular Actions.

Calcific aortic valve disease (CAVD) is a chronic inflammatory disease with slow progression that involves soluble extracellular matrix (ECM) proteins. Previously, we found that recombinant interleukin (IL)-37 suppresses aortic valve interstitial cells (AVIC) inflammatory response through the interaction with IL-18 receptor α-chain (IL-18Rα) on the cell surface. Endogenous IL-37 can be retained in the cytoplasm or released into extracellular spaces. It remains unknown whether recombinant IL-37 exerts the anti-inflammatory effect through intracellular action. Here, we found that recombinant IL-37 suppressed AVIC inflammatory response to soluble ECM proteins. Interestingly, recombinant IL-37 was internalized by human AVICs in an IL-18Rα-independent fashion. Blocking endocytic pathways reduced the internalization and anti-inflammatory potency of recombinant IL-37. Overexpression of IL-37 in human AVICs suppressed soluble ECM proteins-induced NF-κB activation and the production of ICAM-1 and VCAM-1. However, IL-37D20A (mutant IL-37 lacking nucleus-targeting sequences) overexpression had no such effect, and the inflammatory response to soluble ECM proteins was essentially intact in AVICs from transgenic mice expressing IL-37D20A. Together, recombinant IL-37 can be internalized by human AVICs through endocytosis. Intracellular IL-37 exerts an anti-inflammatory effect through a nucleus-targeting mechanism. This study highlights the potent anti-inflammatory effect of recombinant IL-37 in both extracellular and intracellular compartments through distinct mechanisms.

Importance of social vulnerability on long-term outcomes after heart transplantation.

The relationship between social determinants of health and outcomes after heart transplantation has not been examined. The social vulnerability index (SVI) uses United States census data to determine the social vulnerability of every census tract based on 15 factors. This retrospective study seeks to examine the impact of SVI on outcomes after heart transplantation. Adult heart recipients who received a graft between 2012 and 2021 were stratified into SVI percentiles of <75% and SVI of ≥75%. The primary endpoint was survival. The median SVI was 48% (interquartile range: 30%-67%) among 23 700 recipients. One-year survival was similar between groups (91.4 vs 90.7%, log-rank P = .169); however, 5-year survival was lower among individuals living in vulnerable communities (74.8% vs 80.0%, P < .001). This finding persisted despite risk adjustment for other factors associated with mortality (survival time ratio 0.819, 95% confidence interval: 0.755-0.890, P < .001). The incidences of 5-year hospital readmission (81.4% vs 75.4%, P < .001) and graft rejection (40.3% vs 35.7%, P = .004) were higher among individuals living in vulnerable communities. Individuals living in vulnerable communities may be at increased risk of mortality after heart transplantation. These findings suggest there is an opportunity to focus on these recipients undergoing heart transplantation to improve survival.

Up-regulation of Myocardial Klotho Expression to Promote Cardiac Functional Recovery in Old Mice following Endotoxemia.

Objective: Endotoxemic cardiac dysfunction contributes to greater morbidity and mortality in elderly patients with sepsis. This study tested the hypothesis that Klotho insufficiency in aging heart exaggerates and prolongs myocardial inflammation to hinder cardiac function recovery following endotoxemia. Methods: Endotoxin (0.5 mg/kg, iv) was administered to young adult (3-4 months) and old (18-22 months) mice with or without subsequent treatment with recombinant interleukin-37 (IL-37, 50 µg/kg, iv) or recombinant Klotho (10 µg/kg, iv). Cardiac function was analyzed using a microcatheter 24, 48 and 96 h later. Myocardial levels of Klotho, ICAM-1, VCAM-1 and IL-6 were determined by immunoblotting and ELISA. Results: In comparison to young adult mice, old mice had worse cardiac dysfunction accompanied by greater myocardial levels of ICAM-1, VCAM-1 and IL-6 at each time point following endotoxemia and failed to fully recover cardiac function by 96 h. The exacerbated myocardial inflammation and cardiac dysfunction were associated with endotoxemia-caused further reduction of lower myocardial Klotho level in old mice. Recombinant IL-37 promoted inflammation resolution and cardiac functional recovery in old mice. Interestingly, recombinant IL-37 markedly up-regulated myocardial Klotho levels in old mice with or without endotoxemia. Similarly, recombinant Klotho suppressed myocardial inflammatory response and promoted inflammation resolution in old endotoxemic mice, leading to complete recovery of cardiac function by 96 h. Conclusion: Myocardial Klotho insufficiency in old endotoxemic mice exacerbates myocardial inflammatory response, impairs inflammation resolution and thereby hinders cardiac functional recovery. IL-37 is capable of up-regulating myocardial Klotho expression to improve cardiac functional recovery in old endotoxemic mice.

Variability in Heart Yield From Donation After Brain Death Between Organ Procurement Organizations: An Opportunity for Improvement.

Increasing the number of available hearts for transplantation is the best strategy to decrease waitlist mortality. This study examines organ procurement organizations (OPOs) and their role in the transplantation network to determine whether variability in performance exists across them. Adult deceased donors who met the criteria for brain death between 2010 and 2020 (inclusive) in the United States were examined. A regression model was fitted and internally validated using donor characteristics available at the time of organ recovery to predict the likelihood of heart transplantation. Subsequently, an expected heart yield was calculated for each donor using this model. Observed-to-expected (O/E) heart yield ratios for each OPO were calculated by dividing the number of hearts recovered for transplantation by the expected number of recoveries. There were 58 OPOs active during the study period, and on average, OPO activity grew over time. The mean O/E ratio among OPOs was 0.98 (standard deviation ± 0.18). Twenty-one OPOs consistently performed below the expected level (95% confidence intervals < 1.0) and generated a deficit of 1,088 expected transplantations during the study period. The proportion of hearts that were recovered for transplantation varied significantly by OPO categories: low tier 31.8%, mid tier 35.6%, and high tier 36.2% (p < 0.01), even as the expected yield was similar across tiers (p = 0.69). OPO performance accounts for 28% of the variability in successfully transplanting a heart after accounting for the role of referring hospitals, donor families, and transplantation centers. In conclusion, there is significant variability in volume and heart yield from brain-dead donors across OPOs.

Conditional Survival in Lung Transplantation: An Organ Procurement and Transplantation Network Database Analysis.

Lung transplantation survival estimates are traditionally reported as fixed 1-, 5-, and 10-year mortality rates. Alternatively, this study aims to demonstrate how conditional survival models can provide useful prognostic information tailored to the time a recipient has already survived from the date of transplantation. Recipient data was obtained from the Organ Procurement and Transplantation Network database. Data from 24,820 adult recipients over age 18 who received a lung transplant between 2002 and 2017 were included in the study. Five-year observed conditional survival estimates were calculated by recipient age, sex, race, transplant indication, transplant type ( i.e. , single or double), and renal function at the time of transplantation. Significant variability exists in conditional survival following lung transplantation. Each specific recipient characteristic significantly impacted conditional survival during at least one time point in the first 5 years. Younger age and double lung transplantation were the two most positive predictors of improved conditional survival consistently throughout the 5-year study period. Conditional survival in lung transplantation recipients changes over time and across recipient characteristics. Hazards of mortality are not fixed and need to be dynamically evaluated as a function of time. Conditional survival calculations can provide more accurate prognostic predictions than unconditional survival estimates.

Complement Cross Talks With H-K-ATPase to Upregulate Runx2 in Human Aortic Valve Interstitial Cells.

INTRODUCTION: Calcific aortic valve disease (CAVD) is a slowly progressive fibro-calcific valve leaflet disorder. The underlying pathophysiology is complex and not yet well understood. Complement is known to play a role in the pathogenesis of CAVD by upregulating Runx2 to induce profibrogenic change in human aortic valve interstitial cells (AVICs). Furthermore, H-K-ATPase has independently been shown to induce tissue calcification. Therefore, we hypothesized that complement cross talks with H-K-ATPase to upregulate Runx2 in human AVICs. MATERIALS AND METHODS: Human AVICs were isolated from normal and calcified aortic valves. Cells were treated with a variation of complement, H-K-ATPase, or ERK1/2 inhibitors. H-K-ATPase and its association with complement in AVICs were investigated by reverse transcriptase-polymerase chain reaction, immunofluorescence, and Western blot. RESULTS: Calcified human AVICs expressed significantly higher H-K-ATPase level than normal human AVICs. Presence of complement C3 with H-K-ATPase is found in AVICs after complement treatment. Complement induced both H-K-ATPase and Runx2 expression in AVICs, which was associated with increased phosphorylation of ERK1/2 and its downstream molecule p-70 S6. Pharmacological inhibition of either H-K-ATPase or Erk1/2 abolished complement-induced Runx2 expression. CONCLUSIONS: These findings indicate that complement cross talks with H-K-ATPase to upregulate Runx2 in human AVICs by activation of ERK1/2 signaling pathways. The study revealed the potential role of H-K-ATPase in the pathogenesis of CAVD and therapeutically targeting either complement system or H-K-ATPase may limit the development of CAVD.

Challenging Paradigm Limits of Retrograde Cerebral Perfusion During Lower Body Circulatory Arrest.

INTRODUCTION: Retrograde cerebral perfusion (RCP) is a safe and effective technique to augment cerebral protection during lower body circulatory arrest in patients undergoing elective hemiarch replacement. However, recommendations guiding optimal temperature, flow rate, and perfusion pressure are outdated and potentially overly limiting. We report our experience using RCP for elective hemiarch replacement with parameters that challenge the currently accepted paradigm. METHODS: This was a single-center, retrospective analysis of 319 adult patients who underwent elective hemiarch replacement between February 2010 and 2021 using hypothermic lower body circulatory arrest with RCP alone, RCP followed by antegrade cerebral perfusion (ACP), or ACP alone. Flow rates were adjusted to maintain cerebral perfusion pressure between 30 and 50 mm Hg for RCP and between 40 and 60 mm Hg for ACP. RESULTS: RCP was used in 22.6% (n = 72) of cases, whereas ACP alone was performed in 77.4% (n = 247) of cases. Baseline patient characteristics were similar between groups. Patients undergoing RCP demonstrated shorter cross-clamp time (97.0 min versus 100.0 min, P = 0.034) and shorter lower body circulatory arrest time (7.0 min versus 10.0 min, P < 0.0001) compared with ACP alone. Nadir bladder temperature was equivalent between groups (27.3°C versus 27.5°C, P = 0.752). There were no significant differences in postoperative complications, neurologic outcomes, or mortality. CONCLUSIONS: Moderate hypothermic lower body circulatory arrest combined with RCP at target perfusion pressures of 30-50 mm Hg in patients undergoing elective hemiarch replacement results in equivalent neurologic outcomes and overall morbidity to cases using ACP alone. These results challenge the currently accepted paradigm for RCP, which typically uses deep hypothermia while keeping perfusion pressures below 25 mm Hg.

Direct and indirect activation of the adenosine triphosphate-sensitive potassium channel to induce spinal cord ischemic metabolic tolerance.

OBJECTIVES: The mitochondrial adenosine triphosphate-sensitive potassium channel is central to pharmacologically induced tolerance to spinal cord injury. We hypothesized that both direct and nitric oxide-dependent indirect activation of the adenosine triphosphate-sensitive potassium channel contribute to the induction of ischemic metabolic tolerance. METHODS: Spinal cord injury was induced in adult male C57BL/6 mice through 7 minutes of thoracic aortic crossclamping. Pretreatment consisted of intraperitoneal injection 3 consecutive days before injury. Experimental groups were sham (no pretreatment or ischemia, n = 10), spinal cord injury control (pretreatment with normal saline, n = 27), Nicorandil 1.0 mg/kg (direct and indirect adenosine triphosphate-sensitive potassium channel opener, n = 20), Nicorandil 1 mg/kg + carboxy-PTIO 1 mg/kg (nitric oxide scavenger, n = 21), carboxy-PTIO (n = 12), diazoxide 5 mg/kg (selective direct adenosine triphosphate-sensitive potassium channel opener, n = 25), and DZ 5 mg/kg+ carboxy-PTIO 1 mg/kg, carboxy-PTIO (n = 23). Limb motor function was assessed using the Basso Mouse Score (0-9) at 12-hour intervals for 48 hours after ischemia. RESULTS: Motor function was significantly preserved at all time points after ischemia in the Nicorandil pretreatment group compared with ischemic control. The addition of carboxy-PTIO partially attenuated Nicorandil's motor-preserving effect. Motor function in the Nicorandil + carboxy-PTIO group was significantly preserved compared with the spinal cord injury control group (P < .001), but worse than in the Nicorandil group (P = .078). Motor preservation in the diazoxide group was similar to the Nicorandil + carboxy-PTIO group. There was no significant difference between the diazoxide and diazoxide + carboxy-PTIO groups. CONCLUSIONS: Both direct and nitric oxide-dependent indirect activation of the mitochondrial adenosine triphosphate-sensitive potassium channel play an important role in pharmacologically induced motor function preservation.

Glypican 1 promotes proliferation and migration in esophagogastric adenocarcinoma via activating AKT/GSK/ß-catenin pathway.

Background: Glypican 1 (GPC1) is a heparan sulphate proteoglycan cell membrane protein. It is implicated in driving cancers of the breast, brain, pancreas, and prostate; however, its role in esophagogastric cancer (EGAC) remains unexplored. The aim of the study was to investigate and elucidate the molecular mechanistic of GPC1 in human EGAC. Methods: Thirty tissue and 120 microarray sections of EGAC were evaluated with Anti-GPC1 immunohistochemistry. Loss and gain of GPC1 function were performed using lentivirus transfection in EGAC cell lines. Mechanistically, AKT/GSK/ß-catenin pathway was evaluated using AKT inhibitor MK-2206 and Wnt/ß-catenin stimulant LiCl. Results: GPC1 overexpression was found in 102 cases (68%). Overexpression of GPC1 correlated with lymph node metastasis, poor differentiation and decreased overall survival. Lentivirus mediated GPC1 knockdown resulted in decreased cell proliferation, migration, invasion, and colony formation. Knockdown caused G0/G1 cell cycle arrest, increased apoptosis, and reduced epithelial mesenchymal transition (EMT). GPC1 mediated its effects by activation of AKT/GSK/ß-catenin pathway. Conclusions: This is the first descriptive study to decipher the role of GPC1 in EGAC. Our results suggest that GPC1 regulates cell proliferation and growth and may serve as an attractive oncotarget in EGAC.

Venovenous extracorporeal membrane oxygenation support in patients with COVID-19 respiratory failure: A multicenter study.

Objective: The COVID-19 pandemic presents a high mortality rate amongst patients who develop severe acute respiratory distress syndrome (ARDS). The purpose of this study was to evaluate the outcomes of venovenous extracorporeal membrane oxygenation (VV-ECMO) in COVID-19-related ARDS and identify the patients who benefit the most from this procedure. Methods: Adult patients with COVID-19 and severe ARDS requiring VV-ECMO support at 4 academic institutions between March and October 2020 were included. Data were collected through retrospective chart reviews. Bivariate and multivariable analyses were performed with the primary outcome of in-hospital mortality. Results: Fifty-one consecutive patients underwent VV-ECMO with a mean age of 50.4 years; 64.7% were men. Survival to hospital discharge was 62.8%. Median intensive care unit and hospitalization duration were 27.4 days (interquartile range [IQR], 17-37 days) and 34.5 days (IQR, 23-43 days), respectively. Survivors and nonsurvivors had a median ECMO cannulation time of 11 days (IQR, 8-18) and 17 days (IQR, 12-25 days). The average postdecannulation length of stay was 17.5 days (IQR, 12.4-25 days) for survivors and 0 days for nonsurvivors (IQR, 0-6 days). Only 1 nonsurvivor was able to be decannulated. Clinical characteristics associated with mortality between nonsurviors and survivors included increasing age (P = .0048), hemorrhagic stroke (P = .0014), and postoperative dialysis (P = .0013) were associated with mortality in a bivariate model and retained statistical significance in a multivariable model. Conclusions: This multicenter study confirms the effectiveness of VV-ECMO in selected critically ill patients with COVID-19-related severe ARDS. The survival of these patients is comparable to non-COVID-19-related ARDS.

Interleukin 38 alleviates aortic valve calcification by inhibition of NLRP3.

Calcific aortic valve disease (CAVD) is common in people over the age of 65. Progressive valvular calcification is a characteristic of CAVD and due to chronic inflammation in aortic valve interstitial cells (AVICs) resulting in CAVD progression. IL-38 is a naturally occurring anti-inflammatory cytokine; here, we report lower levels of endogenous IL-38 in AVICs isolated from patients' CAVD valves compared to AVICs from non-CAVD valves. Recombinant IL-38 suppressed spontaneous inflammatory activity and calcium deposition in cultured AVICs. In mice, knockdown of IL-38 enhanced the production of inflammatory mediators in murine AVICs exposed to the proinflammatory stimulant matrilin-2. We also observed that in cultured AVICs matrilin-2 stimulation activated the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome with procaspase-1 cleavage into active caspase-1. The addition of IL-38 to matrilin-2-treated AVICs suppressed caspase-1 activation and reduced the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, runt-related transcription factor 2, and alkaline phosphatase. Aged IL-38-deficient mice fed a high-fat diet exhibited aortic valve lesions compared to aged wild-type mice fed the same diet. The interleukin-1 receptor 9 (IL-1R9) is the putative receptor mediating the anti-inflammatory properties of IL-38; we observed that IL-1R9-deficient mice exhibited spontaneous aortic valve thickening and greater calcium deposition in AVICs compared to wild-type mice. These data demonstrate that IL-38 suppresses spontaneous and stimulated osteogenic activity in aortic valve via inhibition of the NLRP3 inflammasome and caspase-1. The findings of this study suggest that IL-38 has therapeutic potential for prevention of CAVD progression.

Evaluating the risk of spinal cord ischemia in zone 2 frozen elephant trunk replacement.

BACKGROUND: The appropriate stent length in frozen elephant trunk replacements (FET) remains debated relative to the risk for paraplegia. However, landing the distal end of the stent beyond the curve of the arch facilitates distal reintervention, which is commonly beyond the 10 cm stent coverage when deployed proximal to the left subclavian artery. The aim of this study was to evaluate outcomes following the use of 15 cm stent grafts in zone 2 (z2, distal to the left common carotid). METHODS: Using our single institution-maintained database, 103 zone 2 FET performed from 2016 to 2020 were reviewed. RESULTS: Of the 103 z2, a 15 cm stent graft was used in 51 operations. The indications for FET included acute and chronic aortic dissection, arch aneurysms, and pseudoaneurysms. The incidence of SCI was 0%. Seven deaths (13.7%) occurred. CONCLUSIONS: The data demonstrates the incidence of post-operative paraplegia to be 0% with 15 cm z2 FET. The understanding of SCI in FET should not only include the stent length but also from where it begins.

Elevated Expression of TLR2 in Aging Hearts Exacerbates Cardiac Inflammatory Response and Adverse Remodeling Following Ischemia and Reperfusion Injury.

This study tested the hypothesis that Toll-like receptor 2 (TLR2) augments the inflammatory responses and adverse remodeling in aging hearts to exacerbate myocardial injury and cardiac dysfunction. Methods: Old (20-22 months old) and adult (4-6 months old) mice of C57BL/6 wild-type and TLR2 knockout (KO) were subjected to coronary artery ligation (30 minutes) and reperfusion (3 or 14 days). Left ventricle function was assessed using a pressure-volume microcatheter. Cardiac infarct size was determined by histology. Levels of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), matrix metalloproteinase 9 (MMP 9), and collagen I in non-ischemic myocardium were assessed by immunoblotting. Monocyte chemoattractant protein-1 (MCP-1), keratinocyte chemoattractant (KC), and interleukin-6 (IL-6) levels in ischemic and non-ischemic myocardium were measured by enzyme-linked immunosorbent assay (ELISA). TLR2 expression in the myocardium of untreated wild type mice was also measured by immunoblotting. Results: Higher levels of MCP-1, KC, IL-6 were induced in both ischemic and non-ischemic myocardium of old wild type mice at day 3 and 14 following ischemia/reperfusion (I/R) than those of adult wild type mice. The hyper-inflammatory responses to I/R in aging hearts were associated with elevated levels of myocardial TLR2. TLR2 KO markedly down-regulated the expression of MCP-1, KC, IL-6, ICAM-1 and VCAM-1 in aging hearts at day 3 and 14 following I/R. The down-regulated inflammatory activity in aging TLR2 KO hearts was associated with attenuated production of MMP 9 and collagen I at day 14 and resulted in reduced infarct size and improved cardiac function. Conclusion: Elevated expression of myocardial TLR2 contributes to the mechanism by which aging exacerbates the inflammatory responses, adverse remodeling and cardiac dysfunction following myocardial I/R in aging.

Monocytes augment inflammatory responses in human aortic valve interstitial cells via ß2-integrin/ICAM-1-mediated signaling.

OBJECTIVE: Inflammatory infiltration in aortic valves promotes calcific aortic valve disease (CAVD) progression. While soluble extracellular matrix (ECM) proteins induce inflammatory responses in aortic valve interstitial cells (AVICs), the impact of monocytes on AVIC inflammatory responses is unknown. We tested the hypothesis that monocytes enhance AVIC inflammatory responses to soluble ECM protein in this study. METHODS: Human AVICs isolated from normal aortic valves were cocultured with monocytes and stimulated with soluble ECM protein (matrilin-2). ICAM-1 and IL-6 productions were assessed. YAP and NF-κB phosphorylation were analyzed. Recombinant CD18, neutralizing antibodies against ß2-integrin or ICAM-1, and inhibitor of YAP or NF-κB were applied. RESULTS: AVIC expression of ICAM-1 and IL-6 was markedly enhanced by the presence of monocytes, although matrilin-2 did not affect monocyte production of ICAM-1 or IL-6. Matrilin-2 up-regulated the expression of monocyte ß2-integrin and AVIC ICAM-1, leading to monocyte-AVIC adhesion. Neutralizing ß2-integrin or ICAM-1 in coculture suppressed monocyte adhesion to AVICs and the expression of ICAM-1 and IL-6. Recombinant CD18 enhanced the matrilin-2-induced ICAM-1 and IL-6 expression in AVIC monoculture. Further, stimulation of coculture with matrilin-2 induced greater YAP and NF-κB phosphorylation. Inhibiting either YAP or NF-κB markedly suppressed the inflammatory response to matrilin-2 in coculture. CONCLUSION: Monocyte ß2-integrin interacts with AVIC ICAM-1 to augment AVIC inflammatory responses to soluble matrilin-2 through enhancing the activation of YAP and NF-κB signaling pathways. Infiltrated monocytes may promote valvular inflammation through cell-cell interaction with AVICs to enhance their sensitivity to damage-associated molecular patterns.

Appraisal of Donation After Circulatory Death: How Far Could We Expand the Heart Donor Pool?

BACKGROUND: the incidence of organ donation after circulatory death (DCD) is increasing; however, heart use has lagged behind other solid organs. Ex vivo perfusion devices are under United States Food and Drug Administration review for use in DCD heart recovery. This study sought to measure the potential increase in the donor pool if DCD heart donation becomes widely adopted. METHODS: DCD donor data were obtained from Organ Procurement and Transplantation Network database. Selection criteria included donor age 18 to 49 years, donors meeting Maastricht III criteria, warm ischemia time ≤30 minutes, and donation between 2015 and 2020. Exclusion criteria were coronary disease, prior myocardial infarction, ejection fraction <0.50, significant valve disease, bacteremia, pulmonary capillary wedge pressure >15 mm Hg, and history of HIV/hepatitis C virus infections. RESULTS: There were 12 813 DCD donors during this period, of which 3528 met study criteria, and 70 hearts (2%) were transplanted. The use of DCD hearts would represent an additional 48 heart transplants per month, which corresponds to a 21% (3458 of 16 521) increase across the country. Median warm ischemia was 23 minutes, with no difference between hearts that were or were not transplanted (23 vs 22.5 minutes, P = .97). The frequency with which other organs were successfully transplanted was kidney, 92%; liver, 44%; lung, 7%; intestine, 0%; and pancreas, 2%. CONCLUSIONS: Wide adoption of DCD heart transplantation could yield a substantial increase in the donor pool size, with approximately 580 additional organs being available each year across the United States. This would represent the largest increase in the donor pool in the modern era of heart transplantation.

Survival following lung transplantation: A population-based nested case-control study.

BACKGROUND: Lung transplantation is the mainstay of treatment for patients with end-stage respiratory failure. This study sought to evaluate survival following transplantation compared to the general population and quantify standardized mortality ratios (SMRs) using a nested case-control study design. METHODS: Control subjects were nonhospitalized inhabitants of the United States identified through the National Longitudinal Mortality Study. Case subjects were adults who underwent lung transplantation between 1990 and 2007 and identified through the Organ Procurement and Transplantation Network. Propensity-matching (5:1, nearest neighbor, caliper = 0.1) was utilized to identify suitable control subjects based on age, sex, race, and location of residency. The primary study endpoint was 10-year survival. RESULTS: About 14,977 lung transplant recipients were matched to 74,885 nonhospitalized US residents. The 10-year survival rate of lung transplant recipients was 28% (95% confidence interval [CI] = 27%-29%). The population expected mortality rate was 19 deaths/100 person-years while the observed ratio was 104 deaths/100 person-years (SMR = 5.39, 95% CI = 5.35-5.43). The largest discrepancies between observed and expected mortality rates were in females (SMR = 5.97), Hispanic (SMR = 10.70), and single lung recipients (SMR = 5.92). SMRs declined over time (1990-1995 = 5.79, 1996-2000 = 5.64, and 2001-2007 = 5.10). Standardized mortality peaks in the first year after transplant and decreases steadily over time. CONCLUSIONS: Lung transplant recipients experience a fivefold higher SMR compared to the nonhospitalized population. Long-term mortality rates have experienced consistent decline over time.

Pro-inflammatory mediators released by activated monocytes promote aortic valve fibrocalcific activity.

BACKGROUND: Calcific aortic valve disease (CAVD) is the most prevalent heart valve disorder in the elderly. Valvular fibrocalcification is a characteristic pathological change. In diseased valves, monocyte accumulation is evident, and aortic valve interstitial cells (AVICs) display greater fibrogenic and osteogenic activities. However, the impact of activated monocytes on valular fibrocalcification remains unclear. We tested the hypothesis that pro-inflammatory mediators from activated monocytes elevate AVIC fibrogenic and osteogenic activities. METHODS AND RESULTS: Picro-sirius red staining and Alizarin red staining revealed collagen and calcium depositions in cultured human AVICs exposed to conditioned media derived from Pam3CSK4-stimulated monocytes (Pam3 CM). Pam3 CM up-regulated alkaline phosphatase (ALP), an osteogenic biomarker, and extracellular matrix proteins collagen I and matrix metalloproteinase-2 (MMP-2). ELISA analysis identified high levels of RANTES and TNF-α in Pam3 CM. Neutralizing RANTES in the Pam3 CM reduced its effect on collagen I and MMP-2 production in AVICs while neutralizing TNF-α attenuated the effect on AVIC ALP production. In addition, Pam3 CM induced NF-κB and JNK activation. While JNK mediated the effect of Pam3 CM on collagen I and MMP-2 production, NF-κB was critical for the effect of Pam3 CM on ALP production in AVICs. CONCLUSIONS: This study demonstrates that activated monocytes elevate the fibrogenic and osteogenic activities in human AVICs through a paracrine mechanism. TNF-α and RANTES mediate the pro-fibrogenic effect of activated monocytes on AVICs through activation of JNK, and TNF-α also activates NF-κB to elevate AVIC osteogenic activity. The results suggest that infiltrated monocytes elevate AVIC fibrocalcific activity to promote CAVD progression.