Molecular Interaction of Soluble Klotho with FGF23 in the Pathobiology of Aortic Valve Lesions Induced by Chronic Kidney Disease.

Chronic kidney disease (CKD) is linked to greater prevalence and rapid progression of calcific aortic valve disease (CAVD) characterized by valvular leaflet fibrosis and calcification. Fibroblast growth factor 23 (FGF23) level is elevated, and anti-aging protein Klotho is reduced in CKD patients. However, the roles of FGF23 and Klotho in the mechanism of aortic valve fibrosis and calcification remain unclear. We hypothesized that FGF23 mediates CKD-induced CAVD by enhancing aortic valve interstitial cell (AVIC) fibrosis and calcification, while soluble Klotho inhibits FGF23 effect. Methods and Results: In an old mouse model of CKD, kidney damages were accompanied by aortic valve thickening and calcification. FGF23 levels in plasma and aortic valve were increased, while Klotho levels were decreased. Recombinant FGF23 elevated the inflammatory, fibrogenic, and osteogenic activities in AVICs. Neutralizing antibody or shRNA targeting FGF23 suppressed the pathobiological activities in AVICs from valves affected by CAVD. FGF23 exerts its effects on AVICs via FGF receptor (FGFR)/Yes-associated protein (YAP) signaling, and inhibition of FGFR/YAP reduced FGF23's potency in AVICs. Recombinant Klotho downregulated the pathobiological activities in AVICs exposed to FGF23. Incubation of FGF23 with Klotho formed complexes and decreased FGF23's potency. Further, treatment of CKD mice with recombinant Klotho attenuated aortic valve lesions. Conclusion: This study demonstrates that CKD induces FGF23 accumulation, Klotho insufficiency and aortic valve lesions in old mice. FGF23 upregulates the inflammatory, fibrogenic and osteogenic activities in AVICs via the FGFR/YAP signaling pathway. Soluble Klotho suppresses FGF23 effect through molecular interaction and is capable of mitigating CKD-induced CAVD.

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.

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.

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.

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.

Simvastatin Inhibits Histologic Changes Associated with Gastroduodenal Reflux in a Murine Model.

BACKGROUND: Observational studies demonstrate a protective effect of statins on the development and progression of esophageal adenocarcinoma. The role of statins in the prevention of reflux-induced esophageal changes remains unknown. AIMS: Using a mixed gastroduodenal reflux mouse model, we hypothesized that oral administration of simvastatin would attenuate reflux-induced mucosal changes of the distal esophagus. METHODS: Human Barrett's (CPB) and esophageal adenocarcinoma (FLO1 and OE19) cells were treated with simvastatin. Cell proliferation and apoptosis were evaluated using the MTS proliferation and annexin V apoptosis assays, respectively. A reflux mouse model was generated by performing a side-to-side anastomosis between the gastroesophageal junction and first portion of the duodenum (duodeno-gastroesophageal anastomosis, DGEA). DGEA mice were fed a standard or simvastatin-containing diet following surgery. Mice were euthanized 6 weeks post-operatively. RESULTS: Simvastatin significantly decreased proliferation and increased apoptosis in all cell lines. Compared to control animals, mice undergoing DGEA who were fed a standard diet demonstrated a fourfold increase in mucosal thickness and significant increase in proliferating cells (p < 0.0001). DGEA mice fed a simvastatin-containing diet had an attenuated response to reflux, with a significant reduction in mucosal hyperplasia and proliferation (p < 0.0001). DGEA mice fed a simvastatin-containing diet demonstrated significant upregulation of procaspase-3 (p = 0.009) and cleaved caspase-3 (p = 0.034) in the distal esophagus. CONCLUSIONS: We demonstrate for the first time a reduction in reflux-induced histologic changes of the distal esophagus following oral administration of simvastatin in vivo. These findings identify simvastatin as a potential preventative agent to inhibit the development and progression of reflux-induced esophageal injury.

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.

Measuring the effect of the COVID-19 pandemic on solid organ transplantation.

BACKGROUND: The COVID-19 pandemic has uniquely affected the United States. We hypothesize that transplantation would be uniquely affected. METHODS: In this population-based cohort study, adult transplantation data were examined as time series data. Autoregressive-integrated-moving-average models of transplantation rates were developed using data from 1990 to 2019 to forecast the 2020 expected rates in a theoretical scenario if the pandemic did not occur to generate observed-to-expected (O/E) ratios. RESULTS: 32,594 transplants were expected in 2020, and only 30,566 occurred (O/E 0.94, CI 0.88-0.99). 58,152 waitlist registrations were expected and 50,241 occurred (O/E 0.86, CI 0.80-0.94). O/E ratios of transplants were kidney 0.92 (0.86-0.98), liver 0.96 (0.89-1.04), heart 1.05 (0.91-1.23), and lung 0.92 (0.82-1.04). O/E ratios of registrations were kidney 0.84 (0.77-0.93), liver 0.95 (0.86-1.06), heart 0.99 (0.85-1.18), and lung 0.80 (0.70-0.94). CONCLUSIONS: The COVID-19 pandemic was associated with a significant deficit in transplantation. The impact was strongest in kidney transplantation and waitlist registration.

Warfarin Induces Calcification of the Aortic Valve Through Extracellular Signal-regulated Kinase 1/2 and ß-catenin Signaling.

BACKGROUND: Recent clinical evidence suggests an association between warfarin use and calcification of the aortic valve. We sought to determine the effect of warfarin on aortic valve interstitial cell (AVIC) osteogenic protein expression and the signaling pathways by which this effect is mediated. METHODS: Human AVICs were isolated from normal aortic valves of patients undergoing cardiac transplantation, whereas diseased AVICs were isolated from patients undergoing aortic valve replacement for aortic stenosis. AVICs were treated with various anticoagulants, and osteogenic protein expression was evaluated using immunoblotting. Phosphorylation of lipoprotein receptor-related protein 6 (LRP6) and extracellular signal-regulated kinase 1/2 (ERK1/2) was evaluated after treatment with warfarin. AVICs were pretreated with LRP6 inhibitor dkk1 and ERK1/2 inhibitor PD98059 followed by treatment with warfarin, and osteogenic protein expression was evaluated. RESULTS: Warfarin, but not heparin or dabigatran, significantly increased Runx-2 and Osx expression in both normal and diseased human AVICs. Upregulation of ß-catenin protein expression and nuclear translocation occurred in diseased AVICs but not normal AVICs after warfarin treatment. Warfarin induced phosphorylation of LRP6 in diseased AVICs only and phosphorylation of ERK1/2 in both normal and diseased AVICs. LRP6 inhibition attenuated warfarin-induced Runx-2 expression in diseased AVICs. ERK1/2 inhibition attenuated warfarin-induced Runx-2 expression in both normal and diseased AVICs. CONCLUSIONS: Warfarin induces osteogenic activity in normal and diseased isolated human AVICs. This effect is mediated by ERK1/2 in both diseased and normal AVICs, but in diseased AVICs ß-catenin signaling also plays a role. These results implicate the role of warfarin in aortic valve calcification and highlight potential mechanisms for warfarin-induced aortic stenosis.

Toll-like Receptor 4 Mediates Reflux-Induced Inflammation in a Murine Reflux Model.

Dysregulation of toll-like receptor (TLR) signaling within the gastrointestinal epithelium has been associated with uncontrolled inflammation and tumorigenesis. We sought to evaluate the role of TLR4 in the development of gastroesophageal reflux-mediated inflammation and mucosal changes of the distal esophagus. Verified human esophageal Barrett's cells with high grade dysplasia (CPB) and esophageal adenocarcinoma cells (OE33) were treated with deoxycholic acid for 24 hours. Cells were pretreated with a TLR4-specific inhibitor peptide 2 hours prior to deoxycholic acid treatment. Inflammatory markers were evaluated using immunoblotting and enzyme-linked immunosorbent assay. A surgical reflux mouse model was generated by performing a side-to-side anastomosis between the second portion of the duodenum and the gastroesophageal junction. Control animals underwent laparotomy with incision and closure of the esophagus superior to the gastroesophageal junction (sham procedure). Esophageal sections were evaluated using hematoxylin and eosin staining and immunohistochemistry. Deoxycholic acid increased expression of inflammatory markers including intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and interleukin 8. Pretreatment with a TLR4 inhibitor significantly decreased deoxycholic acid-induced inflammatory marker expression. C3H/HeNCrl mice demonstrated a significant increase in mucosal hyperplasia and proliferation following DGEA compared to sham procedure. TLR4 mutant mice (C3H/HeJ) undergoing DGEA demonstrated an attenuated hyperplastic and proliferative response compared to C3H/HeNCrl mice. Inhibition of TLR4 signaling attenuates reflux-induced inflammation in vivo. These findings identify TLR4 inhibition as a potential therapeutic target to halt the progression of pathologic esophageal changes developing in the setting of chronic gastroesophageal reflux disease.

Expression of Adhesion Molecules in a Gastroduodenal Reflux Murine Model.

BACKGROUND: Various adhesion molecules, including intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), have been shown to play a role in inflammation as well as contribute to tumor progression and prognosis. We hypothesized that gastroduodenal reflux upregulates ICAM-1 and VCAM-1 expression in the distal esophagus, serving as possible early markers of pathologic esophageal disease. METHODS: Normal human esophageal epithelial cells (HET1A), Barrett cells (CPB), and esophageal adenocarcinoma cells (FLO1 and OE33) were treated with deoxycholic acid at increasing concentrations for 24 hours. Adhesion molecule expression was assessed using immunoblotting. A surgical mouse reflux model was generated by performing a side-to-side anastomosis between the gastroesophageal junction and the first portion of the duodenum (duodenum-gastroesophageal anastomosis). Esophageal sections were evaluated using hematoxylin and eosin staining, immunohistochemistry, and immunofluorescence. RESULTS: Deoxycholic acid induced a significant increase in ICAM-1 and VCAM-1 expression in HET1A, CPB, FLO1, and OE33 cells. Animals undergoing duodenum-gastroesophageal anastomosis demonstrated a significant increase in mucosal hyperplasia (P < .0001) and cellular proliferation (P < .0001) compared with control animals. Immunofluorescence and Western blot analysis of the lower esophagus demonstrated significant upregulation of ICAM-1 (P = .005), with no change in VCAM-1 expression (P = .82). CONCLUSIONS: Our results reveal that ICAM-1 and VCAM-1 are upregulated in response to in vitro reflux treatment of normal esophageal epithelial cells. However, our investigation using a mouse reflux model found ICAM-1 is noticeably upregulated without a concomitant increase in VCAM-1. These findings identify ICAM-1, but not VCAM-1, as a potential player in early esophageal disease developing from chronic reflux exposure.

Optimizing Nicorandil for Spinal Cord Protection in a Murine Model of Complex Aortic Intervention.

There are currently no clinically utilized pharmacological agents for the induction of metabolic tolerance to spinal cord ischemia-reperfusion injury in the setting of complex aortic intervention. Nicorandil, a nitric oxide donor and ATP-sensitive potassium (KATP) channel opener, has shown promise in neuroprotection. However, the optimized clinical application of the drug and its mechanism of neuroprotection remains unclear. We hypothesized that 3-days pretreatment would confer the most effective neuroprotection, mediated by mitochondrial KATP channel activation. Spinal cord injury was induced by 7 minutes of thoracic aortic cross-clamping in adult male C57BL/6 mice. Time course: mice received 0.1 mg/kg nicorandil for 10 min, 4 hours, and 3 consecutive days prior to ischemia compared with control. Dose challenge: mice received 3-days nicorandil pretreatment comparing 0.1 mg/kg, 1.0 mg/kg, 5.0 mg/kg, and saline administration. Mitochondrial KATP channel blocker 5-hydroxy-decanoate (5HD) was co-administered to elucidate mechanism. Limb motor function was evaluated, and viable anterior horn neurons quantified. Nicorandil pretreatment at 4 hours and 3 days before ischemia demonstrated significant motor function preservation; administration 10 minutes before ischemia showed no neuroprotection. All nicorandil doses showed significant motor function preservation. Three days administration of Nicorandil 1.0 mg/kg was most potent. Neuroprotection was completely abolished by 5HD co-administration. Histological analysis showed significant neuron preservation with nicorandil pretreatment, which was attenuated by 5HD co-administration. Three days administration of Nicorandil 1.0 mg/kg showed near-total motor function preservation in a murine spinal cord ischemia-reperfusion model, mediated by the mitochondrial KATP channel.

Creatinine elevations from baseline at the time of cardiac surgery are associated with postoperative complications.

OBJECTIVES: Baseline kidney function is a key predictor of postoperative morbidity and mortality. Whether an increased creatinine at the time of surgery, compared with the lowest creatinine in the 3 months before surgery, is associated with poor outcomes has not been evaluated. We examined whether creatinine elevations from "baseline" were associated with adverse postoperative outcomes. METHODS: A total of 1486 patients who underwent cardiac surgery at the University of Colorado Hospital between January 2011 and May 2016 met inclusion criteria. "Change in creatinine from baseline" was defined as the difference between the immediate presurgical creatinine value and the lowest creatinine value within 3 months preceding surgery. Outcomes evaluated were in-hospital mortality, postoperative infection, postoperative stroke, development of stage 3 acute kidney injury, intensive care unit length of stay, and hospital length of stay. Outcomes were adjusted using a balancing score to account for differences in patient characteristics. RESULTS: There were significant increases in the odds of postoperative infection (odds ratio, 1.17; confidence interval, 1.02-1.34; per 0.1 mg/dL increase in creatinine), stage 3 acute kidney injury (odds ratio, 1.44; confidence interval; 1.18-1.75), intensive care unit length of stay (odds ratio, 1.13; confidence interval, 1.01-1.26), and hospital length of stay (odds ratio, 1.09; confidence interval, 1.05-1.13). There was a significant increase in mortality in the unadjusted analysis, although not after adjustment using a balancing score. There was no association with postoperative stroke. CONCLUSIONS: Elevations in creatinine at the time of surgery above the "baseline" level are associated with increased postoperative morbidity. Baseline creatinine should be established before surgery, and small changes in creatinine should trigger heightened vigilance in the postoperative period.

Reactive Oxygen Species Mediate Nicorandil-induced Metabolic Tolerance to Spinal Cord Injury.

BACKGROUND: Spinal cord injury remains a devastating complication of thoracoabdominal aortic surgery. We previously demonstrated that pretreatment with nicorandil preserved motor function in a murine spinal cord injury model through mitochondrial adenosine triphosphate-sensitive potassium channel activation. We hypothesized that the neuroprotective effect of nicorandil is mediated by downstream generation of reactive oxygen species. METHODS: Spinal cord injury was induced by 7 minutes of thoracic aortic cross-clamping in adult male C57BL/6 mice. Five groups were evaluated: ischemic control (n = 19); nicorandil 1.0 mg/kg (n = 17); nicorandil 1.0 mg/kg plus N acetyl L-cysteine (NAC [reactive oxygen species scavenger, n = 18)]) 150 mg/kg; NAC 150 mg/kg (n = 13); and sham (n = 10). Limb motor function and the number of viable neurons within the anterior horn of the spinal cord were evaluated. RESULTS: Mice in the sham group showed no functional deficits after surgery. Compared with ischemic control, motor function was significantly preserved in the nicorandil pretreatment group at every timepoint after ischemia. In the nicorandil plus NAC group, the motor-preserving effect of nicorandil was completely abolished (P < .001). Viable neuron quantification showed significant neuron preservation in the nicorandil group (29.± 2.6) compared with the ischemic control group (18.5 ± 2.1, P = .024) and nicorandil plus NAC group (14 ± 8.3, P = .001); no significant difference was observed between the ischemic control group and nicorandil plus NAC group (P = 0.768). CONCLUSIONS: Reactive oxygen species generation plays a key role in the nicorandil-induced metabolic tolerance to spinal cord injury. Manipulation of mitochondrial adenosine triphosphate-sensitive potassium channels may lead to improvement in preventing spinal cord injury after thoracoabdominal aortic interventions.

Introduction of robotic surgery leads to increased rate of segmentectomy in patients with lung cancer.

BACKGROUND: Pulmonary segmentectomy provides an anatomic lung resection while avoiding removal of excess normal lung tissue. This may be beneficial in patients with minimal pulmonary reserve who present with early-stage non-small cell lung cancer (NSCLC). However, the operative performance of a segmentectomy using a video-assisted thoracoscopic approach can be technically challenging. We hypothesized that introduction of the robotic surgical system would facilitate the performance of a segmentectomy as measured by an increase in the proportion of segmentectomies being pursued. METHODS: We completed a retrospective analysis of thoracoscopic and robotic anatomic lung resections, including lobectomies and segmentectomies, performed in patients with primary lung cancer from the time of initiation of the robotic thoracic surgery program in November 2017 to November 2019. We compared the proportion of thoracoscopic and robotic segmentectomies performed during the first year compared to the second year of the data collection period. RESULTS: A total of 138 thoracoscopic and robotic anatomic lung resections were performed for primary lung cancer. Types of lung cancer resected (adenocarcinoma, squamous cell carcinoma, or other), tumor size based on clinical T staging (T1-T4), and tumor location were not significantly different between years (P=0.44, P=0.98, and P=0.26, respectively). The proportion of segmentectomies increased from 8.6% during the first year to 25.0% during the second year (P=0.01). One out of 6 (16.7%) segmentectomies were performed using the robot during the first year versus 15 out of 17 (88.2%) during the second year (P=0.003). CONCLUSIONS: Use of the robot led to a significant increase in the number of segmentectomies performed in patients undergoing anatomic lung resection. With increasing lung cancer awareness and widely available screening, a greater number of small, early-stage tumors suitable for segmentectomy will likely be detected. We conclude that robotic-assisted surgery may facilitate the challenges of performing a minimally invasive segmentectomy.

Stage 1 acute kidney injury is independently associated with infection following cardiac surgery.

OBJECTIVES: Severe acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality. METHODS: In this retrospective propensity score-matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS). RESULTS: Stage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71-3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45). CONCLUSIONS: Stage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.