Splenic monocytes mediate inflammatory response and exacerbate myocardial ischemia/reperfusion injury in a mitochondrial cell-free DNA-TLR9-NLRP3-dependent fashion.

The spleen contributes importantly to myocardial ischemia/reperfusion (MI/R) injury. Nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) recruits inflammasomes, initiating inflammatory responses and mediating tissue injury. We hypothesize that myocardial cell-free DNA (cfDNA) activates the splenic NLRP3 inflammasome during early reperfusion, increases systemic inflammatory response, and exacerbates myocardial infarct. Mice were subjected to 40 min of ischemia followed by 0, 1, 5, or 15 min, or 24 h of reperfusion. Splenic leukocyte adoptive transfer was performed by injecting isolated splenocytes to mice with splenectomy performed prior to left coronary artery occlusion. CY-09 (4 mg/kg) was administered 5 min before reperfusion. During post-ischemic reperfusion, splenic protein levels of NLRP3, cleaved caspase-1, and interleukin-1ß (IL-1ß) were significantly elevated and peaked (2.1 ± 0.2-, 3.4 ± 0.4-, and 3.2 ± 0.2-fold increase respectively, p < 0.05) within 5 min of reperfusion. In myocardial tissue, NLRP3 was not upregulated until 24 h after reperfusion. Suppression by CY09, a specific NLRP3 inflammasome inhibitor, or deficiency of NLRP3 significantly reduced myocardial infarct size (17.3% ± 4.2% and 33.2% ± 1.8% decrease respectively, p < 0.01). Adoptive transfer of NLRP3-/- splenocytes to WT mice significantly decreased infarct size compared to transfer of WT splenocytes (19.1% ± 2.8% decrease, p < 0.0001). NLRP3 was mainly activated at 5 min after reperfusion in CD11b+ and LY6G- splenocytes, which significantly increased during reperfusion (24.8% ± 0.7% vs.14.3% ± 0.6%, p < 0.0001). The circulating cfDNA level significantly increased in patients undergoing cardiopulmonary bypass (CPB) (43.3 ± 5.3 ng/mL, compared to pre-CPB 23.8 ± 3.5 ng/mL, p < 0.01). Mitochondrial cfDNA (mt-cfDNA) contributed to NLRP3 activation in macrophages (2.1 ± 0.2-fold increase, p < 0.01), which was inhibited by a Toll-like receptor 9(TLR9) inhibitor. The NLRP3 inflammasome in splenic monocytes is activated and mediates the inflammatory response shortly after reperfusion onset, exacerbating MI/R injury in mt-cfDNA/TLR9-dependent fashion. The schema reveals splenic NLRP3 mediates the inflammatory response in macrophages and exacerbates MI/R in a mitochondrial cfDNA/ TLR9-dependent fashion.

Endoscopic Sleeve Gastroplasty: A Safe Bariatric Intervention for Class III Obesity (BMI > 40).

PURPOSE: Endoscopic sleeve gastroplasty (ESG) is primarily offered to patients with class I and II obesity (BMI 30-40), although there are no guidelines specifying applicability. There is little data comparing ESG to bariatric surgery in patients with class III obesity (BMI > 40). This study evaluates the short-term safety of ESG compared to sleeve gastrectomy (SG) and gastric bypass (RYGB) in patients with class III obesity. METHODS: We retrospectively analyzed over 500,000 patients who underwent ESG, SG, and RNYGB from 2016 to 2020 in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database. ESG patients were stratified by BMI to compare outcomes between class I and II versus class III obese patients. Class III obese patients who underwent ESG were also propensity matched to SG and RNYGB patients for matched comparisons. Primary outcomes included adverse events (AE), readmissions, re-operations, and re-interventions within 30 days. Secondary outcomes included procedure time, length of stay (LOS), and total body weight loss (%TBWL) at 30 days. RESULTS: Among ESG patients, those with BMI > 40 had no difference in AE, readmissions, or re-interventions versus patients with BMI 30-40 (p > 0.05), while achieving greater %TBWL at 30 days (p < 0.05). In comparison to surgery, ESG had similar AE to SG and less than RNYGB, while producing comparable %TBWL to SG and RNYGB at 30 days. CONCLUSIONS: The feasibility and safety of ESG in patients with class III obesity are comparable to patients with class I and II obesity. Additionally, the safety of ESG in patients with class III obesity is comparable to SG and safer than RYGB. Endoscopic sleeve gastroplasty: a safe bariatric intervention for class III obesity (BMI > 40).

Hydroxychloroquine Attenuates Myocardial Ischemic and Post-Ischemic Reperfusion Injury by Inhibiting the Toll-Like Receptor 9 - Type I Interferon Pathway.

Background: We hypothesized that hydroxychloroquine (HCQ) attenuates myocardial ischemia/reperfusion injury (IRI) via TLR9 - type I interferon (IFN-I) pathway inhibition. Methods: The left coronary artery of wild-type (WT) C57BL/6 and congenic TLR9-/- mice was occluded for 40 minutes, with or without 60 minutes of reperfusion (40'/0' or 40'/60'). Either ODN-2088 or HCQ (TLR9 inhibitors), or ODN-1826 (TLR9 agonist) was administered to determine effect on infarct size (IS). After 40'/0', cardiac perfusate (CP) was collected from harvested hearts and administered to either intact WT mice after 20 minutes of ischemia or isolated splenocytes. Type-I interferon (IFNα and IFNß) levels were measured in plasma and splenocyte culture supernatant, and levels of damage associated molecular patterns HMGB1 and cell-free DNA (cfDNA) were measured in CP. Results: After 40'/60', WT mice treated with HCQ or ODN-2088 had significantly reduced IS. TLR9-/- mice and HCQ-treated WT mice undergoing 40'/0' and 40'/60' similarly attenuated IS, with significantly lower IFN-Is in CP after 40'/0' and in plasma after 40'/60'. IS was significantly increased in 40'/0' CP-treated and ODN-1826-treated 20'/60' WT mice. CP-treated WT splenocytes produced significantly higher IFN-I in culture supernatant, which was significantly reduced with HCQ. Conclusions: The TLR9-IFN-I-mediated inflammatory response contributes significantly to both ischemic and post-ischemic myocardial ischemia-reperfusion injury. HMGB1 and cfDNA released from ischemic myocardium activated the intra-myocardial TLR9 - IFN-I inflammatory pathway during ischemia and the extra-myocardial TLR9 - IFN-I inflammatory pathway during reperfusion. Hydroxychloroquine reduces production of IFN-I and attenuates myocardial IRI, likely by inhibiting the TLR9-IFN-I pathway.

Topical Neck Cooling Without Systemic Hypothermia Attenuates Myocardial Ischemic Injury and Post-ischemic Reperfusion Injury.

Background: Following acute myocardial infarction (MI), irreversible damage to the myocardium can only be reduced by shortening the duration between symptom onset and revascularization. While systemic hypothermia has shown promising results in slowing pre-revascularization myocardial damage, it is resource intensive and not conducive to prehospital initiation. We hypothesized that topical neck cooling (NC), an easily implemented therapy for en route transfer to definitive therapy, could similarly attenuate myocardial ischemia-reperfusion injury (IRI). Methods: Using an in vivo mouse model of myocardial IRI, moderate systemic hypothermia or NC was applied following left coronary artery (LCA) occlusion and subsequent reperfusion, at early, late, and post-reperfusion intervals. Vagotomy was performed after late NC in an additional group. Hearts were harvested to measure infarct size. Results: Both hypothermia treatments equally attenuated myocardial infarct size by 60% compared to control. The infarct-sparing effect of NC was temperature-dependent and timing-dependent. Vagotomy at the gastroesophageal junction abolished the infarct-sparing effect of late NC. Cardiac perfusate isolated following ischemia had significantly reduced cardiac troponin T, HMGB1, cell-free DNA, and interferon α and ß levels after NC. Conclusions: Topical neck cooling attenuates myocardial IRI in a vagus nerve-dependent manner, with an effect comparable to that of systemic hypothermia. NC attenuated infarct size when applied during ischemia, with earlier initiation resulting in superior infarct sparing. This novel therapy exerts a cardioprotective effect without requiring significant change in core temperature and may be a promising practical strategy to attenuate myocardial damage while patients await definitive revascularization.

Topical Neck Cooling Prolongs Survival of Rats with Intra-Abdominal Feculent Sepsis by Activation of the Vagus Nerve.

Global hypothermia prolongs survival in rats with intraabdominal feculent sepsis by inhibiting inflammatory responses. We hypothesized that topical neck cooling (TNC) has similar benefits. Septic shock was induced by cecal ligation and incision (CLI) in Sprague Dawley rats. Rats were randomized to sham laparotomy, control with CLI, CLI with TNC, or vagotomy at the gastroesophageal junction before CLI and TNC. Two more groups underwent peritoneal washout with and without TNC two hours after CLI. TNC significantly lowered neck skin temperature (16.7 ± 1.4 vs. 30.5 ± 0.6 °C, p < 0.05) while maintaining core body normothermia. TNC rats recovered from anesthesia 70 min earlier than the control (p < 0.05). Three hours following CLI, the control and vagotomy with TNC groups had significantly more splenic contraction, fewer circulating leukocytes and higher plasma IL-1ß, IL-10 and TNF-α levels than TNC rats (p < 0.05). TNC prolonged survival duration after CLI by a median of four hours vs. control (p < 0.05), but no benefit was seen if vagotomy preceded TNC. Peritoneal washout alone increased survival by 3 h (9.2 (7.8-10.5) h). Survival duration increased dramatically with TNC preceding washout, to a 56% survival rate (>10 days). TNC significantly prolonged the survival of rats with severe intraabdominal sepsis by inhibiting systemic proinflammatory responses by activating vagal anti-inflammatory pathways.

Plasmacytoid Dendritic Cells Mediate Myocardial Ischemia/Reperfusion Injury by Secreting Type I Interferons.

Background We previously demonstrated that ischemically injured cardiomyocytes release cell-free DNA and HMGB1 (high mobility group box 1 protein) into circulation during reperfusion, activating proinflammatory responses and ultimately exacerbating reperfusion injury. We hypothesize that cell-free DNA and HMGB1 mediate myocardial ischemia-reperfusion injury by stimulating plasmacytoid dendritic cells (pDCs) to secrete type I interferon (IFN-I). Methods and Results C57BL/6 and interferon alpha receptor-1 knockout mice underwent 40 minutes of left coronary artery occlusion followed by 60 minutes of reperfusion (40'/60' IR) before infarct size was evaluated by 2,3,5-Triphenyltetrazolium chloride-Blue staining. Cardiac perfusate was acquired in ischemic hearts without reperfusion by antegrade perfusion of the isolated heart. Flow cytometry in pDC-depleted mice treated with multiple doses of plasmacytoid dendritic cell antigen-1 antibody via intraperitoneal injection demonstrated plasmacytoid dendritic cell antigen-1 antibody treatment had no effect on conventional splenic dendritic cells but significantly reduced splenic pDCs by 60%. pDC-depleted mice had significantly smaller infarct size and decreased plasma interferon-α and interferon-ß compared with control. Blockade of the type I interferon signaling pathway with cyclic GMP-AMP synthase inhibitor, stimulator of interferon genes antibody, or interferon regulatory factor 3 antibody upon reperfusion similarly significantly attenuated infarct size by 45%. Plasma levels of interferon-α and interferon-ß were significantly reduced in cyclic GMP-AMP synthase inhibitor-treated mice. Infarct size was significantly reduced by >30% in type I interferon receptor monoclonal antibody-treated mice and interferon alpha receptor-1 knockout mice. In splenocyte culture, 40'/0' cardiac perfusate treatment stimulated interferon-α and interferon-ß production; however, this effect disappeared in the presence of cyclic GMP-AMP synthase inhibitor. Conclusions Type I interferon production is stimulated following myocardial ischemia by cardiogenic cell-free DNA/HMGB1 in a pDC-dependent manner, and subsequently activates type I interferon receptors to exacerbate reperfusion injury. These results identify new potential therapeutic targets to attenuate myocardial ischemia-reperfusion injury.

Pulsed ultrasound attenuates the hyperglycemic exacerbation of myocardial ischemia-reperfusion injury.

OBJECTIVE: Acute hyperglycemia during myocardial infarction worsens outcomes in part by inflammatory mechanisms. Pulsed ultrasound has anti-inflammatory potential in bone healing and neuromodulation. We hypothesized that pulsed ultrasound would attenuate the hyperglycemic exacerbation of myocardial ischemia-reperfusion injury via the cholinergic anti-inflammatory pathway. METHODS: Acute hyperglycemia was induced in wild-type C57BL6 or acetylcholine-receptor knockout (α7nAChR-/-) mice by intraperitoneal injection of glucose. Pulsed ultrasound (frequency 7 MHz, bursting mechanical index 1.2, duration 1 second, repeated every 6 seconds for 2 minutes, 20-second total exposure) was performed at the spleen or neck after glucose injection. Separate mice underwent vagotomy before treatment. The left coronary artery was occluded for 20 minutes, followed by 60 minutes of reperfusion. The primary end point was infarct size in explanted hearts. RESULTS: Splenic pulsed ultrasound significantly decreased infarct size in wild-type C57BL6 mice exposed to acute hyperglycemia and myocardial ischemia-reperfusion injury (5.2% ± 4.4% vs 16.9% ± 12.5% of risk region, P = .013). Knockout of α7nAChR abrogated the beneficial effect of splenic pulsed ultrasound (22.2% ± 12.1%, P = .79 vs control). Neck pulsed ultrasound attenuated the hyperglycemic exacerbation of myocardial infarct size (3.5% ± 4.8%, P = .004 vs control); however, the cardioprotective effect disappeared in mice that underwent vagotomy. Plasma acetylcholine, ß2 adrenergic receptor, and phosphorylated Akt levels were increased after splenic pulsed ultrasound treatment. CONCLUSIONS: Pulsed ultrasound treatment of the spleen or neck attenuated the hyperglycemic exacerbation of myocardial ischemia-reperfusion injury leading to a 3-fold decrease in infarct size. Pulsed ultrasound may provide cardioprotection via the cholinergic anti-inflammatory pathway and could be a promising new nonpharmacologic, noninvasive therapy to reduce infarct size during acute myocardial infarction and improve patient outcomes.

Pulsed Ultrasound of the Spleen Prolongs Survival of Rats With Severe Intra-abdominal Sepsis.

BACKGROUND: The spleen is an important contributor to the uncontrolled, excessive release of proinflammatory signals during sepsis that leads to the development of tissue injury and diffuse end-organ dysfunction. Therapeutic pulsed ultrasound (pUS) has been shown to inhibit splenic leukocyte release and reduce cytokine production in other inflammatory disease processes. We hypothesized that pUS treatment inhibits spleen-derived inflammatory responses and increases survival duration in rats with severe intra-abdominal sepsis leading to septic shock. MATERIALS AND METHODS: Rats with intra-abdominal sepsis, induced by cecal ligation and incision, underwent abdominal washout, intra-peritoneal administration of cefazolin, and then either no further treatment (control), splenectomy, or pUS of the spleen. Animals were observed for the primary endpoint of survival duration. RESULTS: Survival curves were significantly different for all groups (P < 0.01). Median survival increased from 9.5 h in control rats to 19.8 h in pUS rats and 35.0 h in splenectomy rats (P < 0.01). At 4 h after cecal ligation and incision, the pUS group had decreased splenic contraction and leukocyte count (P = 0.03) compared with control, indicating reduced exodus of splenic leukocytes. In addition, elevation in plasma TNF-α and MCP-1 was significantly attenuated in the pUS group (P < 0.05 versus control). Splenic ß2 adrenergic receptor levels and phosphorylated Akt were significantly more elevated in the pUS group (P < 0.01 versus control). CONCLUSIONS: pUS significantly prolonged the survival duration of rats with severe intra-abdominal sepsis. This treatment may be an effective, noninvasive therapy that dampens detrimental immune responses during septic shock by activating ß2 adrenergic receptor-Akt phosphorylation in the cholinergic anti-inflammatory pathway.

Therapeutic Efficacy of Alpha-Lipoic Acid against Acute Myocardial Infarction and Chronic Left Ventricular Remodeling in Mice.

BACKGROUND: We hypothesized that daily administration of a potent antioxidant (α-lipoic acid: ALA) would protect the heart against both acute myocardial infarction (AMI) and left ventricular remodeling (LVR) post-AMI. METHODS AND RESULTS: Two separate studies were conducted. In the AMI study, C57Bl/6 mice were fed ALA daily for 7 d prior to a 45-minute occlusion of the left coronary artery (LCA). Mean infarct size in control mice (fed water) was 60 ± 2%. Mean infarct size in ALA-treated mice was 42 ± 3% in the 15 mg/kg·d group and 39 ± 3% in the 75 mg/kg·d group (both P < 0.05 vs. control). In the LVR study, AMI increased LV end-systolic volume (LVESV) and reduced LV ejection fraction (LVEF) to a similar extent in both groups when assessed by cardiac MRI 1 day after a 2-hour LCA occlusion. Treatment with ALA (75 mg/kg·d) or H2O was initiated 1 day post-AMI and continued until study's end. Both LVESV and LVEF in ALA-treated mice were significantly improved over control when assessed 28 or 56 days post-AMI. Furthermore, the survival rate in ALA-treated mice was 63% better than in control mice by 56 days post-AMI. CONCLUSIONS: Daily oral ingestion of ALA not only protects mice against AMI but also attenuates LVR and preserves contractile function in the months that follow.

Robotic compared with laparoscopic cholecystectomy: A propensity matched analysis.

BACKGROUND: As robotic surgery becomes more ubiquitous, determining clinical benefit is necessary to justify the cost and time investment required to become proficient. We hypothesized that robotic cholecystectomy would be associated with improved clinical outcomes but also increased cost as compared with standard laparoscopic cholecystectomy. MATERIALS AND METHODS: All patients undergoing robotic or laparoscopic cholecystectomy at a single academic hospital between 2007 and 2017 were identified using an institutional clinical data repository. Patients were stratified by operative approach (robotic versus laparoscopic) for comparison and propensity score matched 1:10 based on relevant comorbidities and demographics. Categorical variables were analyzed by the χ2 test and continuous variables using the Mann-Whitney U test. RESULTS: A total of 3,255 patients underwent cholecystectomy during the study period. We observed no differences in demographics or body mass index, but greater rates of diabetes mellitus, hypertension, and gastroesophageal reflux disease were present in the laparoscopic group. After matching (n = 106 robotic, n = 1,060 laparoscopic), there were no differences in preoperative comorbidities. Patients who underwent robotic cholecystectomy had lesser durations of stay (robotic: 0.1 ± 0.7 versus laparoscopic: 0.8 ± 1.9, P < .0001) and lesser 90-day readmission rates (robotic: 0% [0], laparoscopic: 4.1% [43], P = 0.035); however, both operative and hospital costs were greater compared with laparoscopic cholecystectomy. CONCLUSION: Robotic cholecystectomy is associated with lesser duration of stay and lesser readmission rate within 90 days of the index operation, but also greater operative duration and hospital cost compared with laparoscopic cholecystectomy. Hospitals and surgeons need to consider the improved clinical outcomes but also the monetary and time investment required before pursuing robotic cholecystectomy.

Adenosine 2A Receptor Activation Attenuates Ischemia Reperfusion Injury During Extracorporeal Cardiopulmonary Resuscitation.

OBJECTIVE: We tested the hypothesis that systemic administration of an A2AR agonist will reduce multiorgan IRI in a porcine model of ECPR. SUMMARY BACKGROUND DATA: Advances in ECPR have decreased mortality after cardiac arrest; however, subsequent IRI contributes to late multisystem organ failure. Attenuation of IRI has been reported with the use of an A2AR agonist. METHODS: Adult swine underwent 20 minutes of circulatory arrest, induced by ventricular fibrillation, followed by 6 hours of reperfusion with ECPR. Animals were randomized to vehicle control, low-dose A2AR agonist, or high-dose A2AR agonist. A perfusion specialist using a goal-directed resuscitation protocol managed all the animals during the reperfusion period. Hourly blood, urine, and tissue samples were collected. Biochemical and microarray analyses were performed to identify differential inflammatory markers and gene expression between groups. RESULTS: Both the treatment groups demonstrated significantly higher percent reduction from peak lactate after reperfusion compared with vehicle controls. Control animals required significantly more fluid, epinephrine, and higher final pump flow while having lower urine output than both the treatment groups. The treatment groups had lower urine NGAL, an early marker of kidney injury (P = 0.01), lower plasma aspartate aminotransferase, and reduced rate of troponin rise (P = 0.01). Pro-inflammatory cytokines were lower while anti-inflammatory cytokines were significantly higher in the treatment groups. CONCLUSIONS: Using a novel and clinically relevant porcine model of circulatory arrest and ECPR, we demonstrated that a selective A2AR agonist significantly attenuated systemic IRI and warrants clinical investigation.

The myocardial infarct-exacerbating effect of cell-free DNA is mediated by the high-mobility group box 1-receptor for advanced glycation end products-Toll-like receptor 9 pathway.

INTRODUCTION: Damage-associated molecular patterns, such as high-mobility group box 1 (HMGB1) and cell-free DNA (cfDNA), play critical roles in mediating ischemia-reperfusion injury (IRI). HMGB1 activates RAGE to exacerbate IRI, but the mechanism underlying cfDNA-induced myocardial IRI remains unknown. We hypothesized that the infarct-exacerbating effect of cfDNA is mediated by HMGB1 and receptor for advanced glycation end products (RAGE). METHODS: C57BL/6 wild type mice, RAGE knockout (KO), and Toll-like receptor 9 KO mice underwent 20- or 40-minute occlusions of the left coronary artery followed by up to 60 minutes of reperfusion. Cardiac coronary perfusate was acquired from ischemic hearts without reperfusion. Exogenous mitochondrial DNA was acquired from livers of normal C57BL/6 mice. Myocardial infarct size (IS) was reported as percent risk region, as measured by 2,3,5-triphenyltetrazolium chloride and Phthalo blue (Heucotech, Fairless Hill, Pa) staining. cfDNA levels were measured by Sytox Green assay (Thermo Fisher Scientific, Waltham, Mass) and/or spectrophotometer. RESULTS: Free HMGB1 and cfDNA levels were increased in the ischemic myocardium during prolonged ischemia and subsequently in the plasma during reperfusion. In C57BL/6 mice undergoing 40'/60' IRI, deoxyribonuclease I, or anti-HMGB1 monoclonal antibody reduced IS by approximately half to 29.0% ± 5.2% and 24.3% ± 3.5% (P < .05 vs control 54.3% ± 3.4%). However, combined treatment with deoxyribonuclease I + anti-HMGB1 monoclonal antibody did not further attenuate IS (29.3% ± 4.9%). In C57BL/6 mice undergoing 20'/60' IRI, injection of 40'/5' plasma upon reperfusion increased IS by more than 3-fold (to 19.9 ± 4.3; P < .05). This IS exacerbation was abolished by pretreating the plasma with deoxyribonuclease I or by depleting the HMGB1 by immunoprecipitation, or by splenectomy. The infarct-exacerbating effect also disappeared in RAGE KO mice and Toll-like receptor 9 KO mice. Injection of 40'/0' coronary perfusate upon reperfusion similarly increased IS. The levels of HMGB1 and cfDNA were significantly elevated in the 40'/0' coronary perfusate and 40'/reperfusion (min) plasma but not in those with 10' ischemia. In C57BL/6 mice without IRI, 40'/5' plasma significantly increased the interleukin-1ß protein and messenger RNA expression in the spleen by 30 minutes after injection. Intravenous bolus injection of recombinant HMGB1 (0.1 µg/g) or mitochondrial DNA (0.5 µg/g) 5 minutes before reperfusion did not exacerbate IS (P = not significant vs control). However, combined administration of recombinant HMGB1 + mitochondrial DNA significantly increased IS (P < .05 vs individual treated groups) and this infarct-exacerbating effect disappeared in RAGE KO mice and splenectomized C57BL/6 mice. The accumulation of cfDNA in the spleen after combined recombinant HMGB1 + mitochondrial DNA treatment was significantly more elevated in C57BL/6 mice than in RAGE KO mice. CONCLUSIONS: Both HMGB1 and cfDNA are released from the heart upon reperfusion after prolonged ischemia and both contribute importantly and interdependently to post-IRI by a common RAGE-Toll-like receptor 9-dependent mechanism. Depleting either of these 2 damage-associated molecular patterns suffices to significantly reduce IS by approximately 50%.

Infarct-Sparing Effect of Adenosine A2B Receptor Agonist Is Primarily Due to Its Action on Splenic Leukocytes Via a PI3K/Akt/IL-10 Pathway.

BACKGROUND: Adenosine A2B receptor (A2BAR) agonist reduces myocardial reperfusion injury by acting on inflammatory cells. Recently, a cardiosplenic axis was shown to mediate the myocardial postischemic reperfusion injury. This study aimed to explore whether the infarct-squaring effect of A2BAR agonist was primarily due to its action on splenic leukocytes. METHODS: C57BL6 (wild type [WT]) mice underwent 40 min of left coronary artery occlusion followed by 60 min of reperfusion. A2BAR knockout (KO) and interleukin (IL)-10KO mice served as donors for splenic leukocytes. Acute splenectomy was performed 30 min before ischemia. The acute splenic leukocyte adoptive transfer was performed by injecting 5 × 106 live splenic leukocytes into splenectomized mice. BAY 60-6583, an A2BAR agonist, was injected by i.v. 15 min before ischemia. The infarct size (IS) was determined using 2,3,5-triphenyltetrazolium chloride and Phthalo blue staining. The expression of p-Akt and IL-10 was estimated by Western blotting. Immunofluorescence staining assessed the localization of IL-10 expression. RESULTS: BAY 60-6583 reduced the myocardial IS in intact mice but failed to reduce the same in splenectomized mice, which had a smaller IS than intact mice. BAY 60-6583 reduced the IS in splenectomized mice with the acute transfer of WT splenic leukocytes; however, it did not protect the heart of splenectomized mice with the acute transfer of A2BRKO splenic leukocytes. Furthermore, BAY 60-6583 increased the levels of p-Akt and IL-10 in the WT spleen. Moreover, it did not exert any protective effect in IL-10KO mice. CONCLUSIONS: A2BAR activation before ischemia stimulated the IL-10 production in splenic leukocytes via a PI3K/Akt pathway, thereby exerting anti-inflammatory effects that limited the myocardial reperfusion injury.

Stimulation of the Beta2 Adrenergic Receptor at Reperfusion Limits Myocardial Reperfusion Injury via an Interleukin-10-Dependent Anti-Inflammatory Pathway in the Spleen.

BACKGROUND: In addition to the airway-relaxing effects, ß2 adrenergic receptor (ß2AR) agonists are also found to have broad anti-inflammatory effects. The current study was conducted to define the role of ß2AR agonists in limiting myocardial ischemia/reperfusion injury (IRI). Methods and Results: Adult male wild-type (WT) and interleukin (IL)-10 knockout (KO) mice underwent a 40-min left coronary artery ligation and 60-min reperfusion. A selective ß2AR agonist, Clenbuterol, at doses of 0.1 µg or 1 µg/g weight i.v. 5 min before reperfusion, significantly reduced myocardial infarct size (IS) by 28% and 39% (vs. control, P<0.05) in WT mice respectively, but had no protective effect in IL-10 KO mice. Inhalational therapy with nebulized Clenbuterol, Albuterol, Salmeterol or Arformoterol immediately before ischemia significantly reduced IS (P<0.05) in WT mice. Splenectomy similarly reduced IS as Clenbuterol-treated mice, but intravenous Clenbuterol did not further reduce IS in splenectomized mice. In splenectomized WT mice, acute transfer of isolated splenocytes, not the Clenbuterol-pretreated splenocytes, restored the myocardial IS to the level of intact mice. Intravenous Clenbuterol significantly increased splenic protein levels of ß2AR, phosphorylated Akt and IL-10 and plasma IL-10, and inhibited the expression of pro-inflammatory mRNAs. CONCLUSIONS: Both intravenous and inhalational ß2AR agonists exert a cardioprotective effect against IRI by activating the anti-inflammatory ß2AR-IL-10 pathway.

Inguinal hernia repair: is there a benefit to using the robot?

BACKGROUND: The number of robotic surgical procedures performed yearly is constantly rising, due to improved dexterity and visualization capabilities compared with conventional methods. We hypothesized that outcomes after robotic-assisted inguinal hernia repair would not be significantly different from outcomes after laparoscopic or open repair. METHODS: All patients undergoing inguinal hernia repair between 2012 and 2016 were identified using institutional American College of Surgeons National Surgical Quality Improvement Program data. Demographics; preoperative, intraoperative, and postoperative characteristics; and outcomes were evaluated based on method of repair (Robot, Lap, or Open). Categorical variables were analyzed by Chi-square test and continuous variables using Mann-Whitney U. RESULTS: A total of 510 patients were identified who underwent unilateral inguinal hernia repair (Robot: 13.8% [n = 69], Lap: 48.1% [n = 241], Open: 38.1% [n = 191]). There were no demographic differences between groups other than age (Robot: 52 [39-62], Lap: 57 [45-67], and Open: 56 [48-67] years, p = 0.03). Operative duration was also different (Robot: 105 [76-146] vs. Lap: 81 [61-103] vs. Open: 71 [56-88] min, p < 0.001). There were no operative mortalities and all patients except one were discharged home the same day. Postoperative occurrences (adverse events, readmissions, and death) were similar between groups (Robot: 2.9% [2], Lap: 3.3% [8], Open: 5.2% [10], p = 0.53). Although rare, there was a significant difference in rate of postoperative skin and soft tissue infection (Robot: 2.9% [2] vs. Lap: 0% [0] vs. Open: 0.5% [1], p = 0.02). Cost was significantly different between groups (Robot: $7162 [$5942-8375] vs. Lap: $4527 [$2310-6003] vs. Open: $4264 [$3277-5143], p < 0.001). CONCLUSIONS: Outcomes after robotic-assisted inguinal hernia repair were similar to outcomes after laparoscopic or open repair. Longer operative duration during robotic repair may contribute to higher rates of skin and soft tissue infection. Higher cost should be considered, along with surgeon comfort level and patient preference when deciding whether inguinal hernia repair is approached robotically.

Effect of hypothermia on splenic leukocyte modulation and survival duration in severely septic rats.

BACKGROUND: Therapeutic hypothermia (HT) in severe septic shock is associated with prolonged survival. We hypothesized that moderate HT would prolong survival and modulate the inflammatory response in rats with septic shock by exerting its therapeutic effect on splenic leukocytes. MATERIALS AND METHODS: Severe septic shock was created in rats by cecal ligation and incision (CLI). One hour after CLI or laparotomy, rats were randomized to sham, normothermia (NT), or 4 h of HT followed by 2 h of rewarming. HT (31 ± 1°C) was induced using a cooling blanket and monitored via a rectal temperature probe. RESULTS: Survival duration was 2.78 ± 1.0 h in NT rats and 8.33 ± 0.32 h in HT rats (n = 8/group, P < 0.0001). In separate groups, 3 h after CLI, the spleen weight was significantly smaller in NT rats (769 ± 100 mg) than in HT rats (947 ± 157 mg, P = 0.04). Fluorescent immunostaining of formyl peptide receptors on leukocytes in spleen tissue showed considerably higher formyl peptide receptor expression in HT rats than in NT rats. Significantly elevated proinflammatory cytokines and myeloperoxidase enzyme in plasma were found in NT rats compared with HT rats. Anti-inflammatory cytokine, interleukin-10, was significantly higher in HT rats. Both proinflammatory cytokines and plasma myeloperoxidase were significantly reduced in splenectomized NT rats. CONCLUSIONS: Moderate hypothermic therapy significantly prolongs the survival duration of rats with severe septic shock. HT dampens the inflammatory response during septic shock by modulating the spleen to an anti-inflammatory mode and preventing the spleen from releasing activated splenic leukocytes into the blood.

The spleen contributes importantly to myocardial infarct exacerbation during post-ischemic reperfusion in mice via signaling between cardiac HMGB1 and splenic RAGE.

The spleen plays a critical role in post-infarct myocardial remodeling. However, the role of the spleen in exacerbating myocardial infarction (MI) during acute ischemia/reperfusion (I/R) injury is unknown. The present study tests the hypothesis that splenic leukocytes are activated by substances released from ischemic myocardium to subsequently exacerbate myocardial injury during reperfusion. The left coronary artery in C57BL/6 mice underwent various durations of occlusion followed by 60 min of reperfusion (denoted as min/min of I/R) with or without splenectomy prior to I/R injury. Splenectomy significantly decreased myocardial infarct size (IS) in 40'/60' and 50'/60' groups (p < 0.05); however, it had no effect on IS in 10'/60', 20'/60' and 30'/60' groups (p = NS). In the 20'/60' group, infusion of 40-min ischemic heart homogenate (40-IHH) upon reperfusion increased IS by >threefold versus infusion of 10-IHH (p < 0.05). Splenectomy abolished the infarct-exacerbating effect of 40-IHH, which was restored by splenic leukocyte adoptive transfer (SPAT). Furthermore, depletion of HMGB1 in the 40-IHH group abolished its infarct-exacerbating effect (p < 0.05), and 40-IHH failed to increase IS in both RAGE(-/-) mice and splenectomized wild-type mice with SPAT from RAGE(-/-) mice. The injection of 40-IHH significantly increased formyl peptide receptor 1 (FPR1) expression in sham spleens when compared to 10-IHH-treated sham and control mice. cFLFLF, a specific FPR1 antagonist, reduced myocardial neutrophil infiltration and abrogated the infarct-exacerbating effect of 40-IHH during reperfusion. A cardio (HMGB1)-splenic (RAGE receptor) signaling axis exists and contributes to myocardial infarct exacerbation during reperfusion after prolonged ischemic insults by activating splenic leukocytes. The FPR1 is a potential therapeutic target for inhibiting the cardio-splenic axis that augments infarct size during post-ischemic reperfusion.

Adenosine 2B Receptor Activation Reduces Myocardial Reperfusion Injury by Promoting Anti-Inflammatory Macrophages Differentiation via PI3K/Akt Pathway.

BACKGROUND: Activation of the adenosine A2B receptor (A2BR) can reduce myocardial ischemia/reperfusion (IR) injury. However, the mechanism underlying the A2BR-mediated cardioprotection is less clear. The present study was designed to investigate the potential mechanisms of cardioprotection mediated by A2BR. METHODS AND RESULTS: C57BL/6 mice underwent 40-minute ischemia and 60-minute reperfusion. ATL-801, a potent selective A2BR antagonist, could not block ischemic preconditioning induced protection. BAY 60-6583, a highly selective A2BR agonist, significantly reduced myocardial infarct size, and its protective effect could be blocked by either ATL-801 or wortmannin. BAY 60-6583 increased phosphorylated Akt (p-Akt) levels in the heart at 10 min of reperfusion, and this phosphorylation could also be blocked by ATL-801 or wortmannin. Furthermore, BAY 60-6583 significantly increased M2 macrophages and decreased M1 macrophage and neutrophils infiltration in reperfused hearts, which also could be blocked by wortmannin. Meanwhile, confocal imaging studies showed that the majority of Akt phosphorylation in the heart was colocalized to CD206+ cells in both control and BAY 60-6583 pretreated hearts. CONCLUSION: Our results indicated that pretreatment with BAY 60-6583 protects the heart against myocardial IR injury by its anti-inflammatory effects, probably by modulating macrophages phenotype switching via a PI3K/Akt pathway.

Splenic leukocytes mediate the hyperglycemic exacerbation of myocardial infarct size in mice.

Acute hyperglycemia during acute myocardial infarction is associated with worse myocardial injury and increased mortality. Using a mouse model of myocardial ischemia/reperfusion injury, we tested the hypothesis that acute hyperglycemia activates splenic leukocytes and subsequently exacerbates myocardial infarct size. We then examined whether the adverse effects of hyperglycemia could be attenuated by a potent anti-inflammatory agent (an agonist of the adenosine A2A receptor) administered immediately prior to reperfusion. C57BL6 (WT) mice underwent 30-min LAD occlusion and 60-min reperfusion with or without prior splenectomy. Acute hyperglycemia before ischemia increased myocardial infarct size (IS) by 43% (p < 0.05). Splenectomy before ischemia did not change IS (vs. control, p = NS) but did serve to prevent the exacerbation of IS by hyperglycemia. Acute hyperglycemia activated splenic leukocytes by increasing formyl peptide receptor expression and reactive oxygen species production before ischemia, and enhanced splenic neutrophil release with resultant peripheral neutrophilia and increased myocardial neutrophil infiltration during reperfusion. Acute adoptive transfer of splenic leukocytes to splenectomized mice before ischemia restored the hyperglycemic exacerbation of infarct size. ATL146e, an adenosine 2A receptor (A2AR) agonist, abolished neutrophilia during reperfusion and reduced IS in hyperglycemic mice. ATL146e also reduced IS in splenectomized hyperglycemic mice with transfer of WT splenic leukocytes, but not with transfer of splenic leukocytes from A2AR knockout mice. Acute hyperglycemia prior to myocardial ischemia and reperfusion exacerbates IS by activating splenic leukocytes. ATL146e administered at reperfusion suffices to abrogate the hyperglycemic exacerbation of IS by acting on A2ARs on splenic leukocytes.

The infarct-sparing effect of IB-MECA against myocardial ischemia/reperfusion injury in mice is mediated by sequential activation of adenosine A3 and A 2A receptors.

Conflicting results exist regarding the role of A3 adenosine receptors (A3ARs) in mediating cardioprotection during reperfusion following myocardial infarction. We hypothesized that the effects of the A3AR agonist IB-MECA to produce cardioprotection might involve activation of other adenosine receptor subtypes. C57Bl/6 (B6), A3AR KO, A2AAR KO, and A2AAR KO/WT bone marrow chimeric mice were assigned to 12 groups undergoing either hemodynamic studies or 45 min of LAD occlusion and 60 min of reperfusion. IB-MECA (100 µg/kg) or vehicle was administered by iv bolus 5 min before reperfusion. Radioligand binding assays showed that IB-MECA has high affinity for the mouse A3AR (K i = 0.17 ± 0.05 nM), but also can bind with lower affinity to the A1AR (9.0 ± 2.4 nM) or the A2AAR (56.5 ± 10.2 nM). IB-MECA caused bi-phasic hemodynamic changes, which were completely absent in A3AR KO mice and were modified by A2AAR blockade or deletion. IB-MECA stimulated histamine release, increased heart rate, and significantly reduced IF size in B6 mice from 61.5 ± 1.4 to 48.6 ± 2.4% of risk region (RR; 21% reduction, p < 0.05) but not in A3AR KO mice. Compared to B6, A3AR KO mice had significantly reduced IF size (p < 0.05). In B6/B6 bone marrow chimeras, IB-MECA caused a 47% reduction of IF size (from 47.3 ± 3.9 to 24.7 ± 4.5, p < 0.05). However, no significant cardioprotective effect of IB-MECA was observed in A2AARKO/B6 mice, which lacked A2AARs only on their bone marrow-derived cells. Activation of A3ARs induces a bi-phasic hemodynamic response, which is partially mediated by activation of A2AARs. The cardioprotective effect of IB-MECA is due to the initial activation of A3AR followed by activation of A2AARs in bone marrow-derived cells.