Age-related dysfunction of p53-regulated phagocytic activity in macrophages.

Aging promotes polarization of M2-like macrophages to M1-like macrophages and reduces their phagocytic ability. However, the molecular mechanisms underlying these aging-related changes remain poorly understood. Here, we demonstrate that p53 regulates phagocytic activity in macrophages from young mice but not in those from old ones. Macrophages from both old and young mice expressed functional p53 to induce target genes including p21 and Mdm2. In macrophages from young mice, chemically induced p53 decreased phagocytic activity and c-Myc levels, with the latter change reducing M2-related genes. However, in macrophages from old mice, phagocytic activity and c-Myc expression were independent of p53 activity. Furthermore, c-Myc suppression did not affect M2-related genes in old-mouse macrophages. These results demonstrate that dysregulation of p53 function is a molecular mechanism underlying reduced phagocytic activity in aged-mouse macrophages.

Kinetics of cytokine mRNA and protein expression by plastic adherent cells in the thymus after split-dose irradiation.

Whole body irradiation causes significant apoptosis in various tissues such as the thymus. If apoptotic cells outnumber the phagocytic capacity of macrophages, apoptosis becomes secondary necrosis, inducing inflammatory cytokine expression in macrophages. Radiation also induces thymic lymphomas in C57BL/6 mice after four consecutive irradiations with 1.6 Gy X-rays with nearly 100% incidence. Since cancer development is modulated by a microenvironment involving macrophages, we examined the kinetics of thymocyte number and plastic adherent cell number in the thymus as well as cytokine mRNA expression by plastic adherent cells in the thymus after split-dose irradiation. Upon split-dose irradiation, thymocyte number changed dramatically, whereas plastic adherent cell number did not. Among cytokine mRNAs tested, IL-1ß, IL-11 and IL-12p40 mRNAs were up regulated 2 days after the 1st and 2nd, 3rd and 4th, and 2nd and 3rd irradiations, respectively. On the other hand, TNF-α mRNA was up regulated 2 days after the 3rd irradiation and 2 weeks after the 4th irradiation. The level of IL-11 protein was also increased 2 days after 3rd and 4th irradiations. These results suggest that, upon split-dose irradiation, macrophages in the thymus produce various cytokines in a time-dependent manner, thereby contributing to induction of thymic lymphomas.

Endovascular repair with extracorporeal membrane oxygenation as a rescue strategy for aortobronchial fistula: a case report.

Aortobronchial fistula (ABF) is a rare and potentially lethal complication of thoracic aortic replacement surgery. Currently, thoracic endovascular aortic repair (TEVAR) has emerged as a less invasive alternative to open surgery for ABF to facilitate prompt hemostasis. However, there are no published reports of TEVAR for ABF, particularly for presentation with life-threatening respiratory failure from massive hemoptysis. A 48-year-old male patient, who had recently undergone aortic root and arch replacement due to aortic dissection, was transferred to the emergency department with massive hemoptysis and severe dyspnea. A single-lumen endotracheal tube was immediately placed in the right main bronchus to protect the nonbleeding lung from spillage of blood. Chest computed tomography (CT) showed leakage of contrast material from the distal anastomosis of the aortic graft and consolidated lung tissue adjacent to the leakage. He was diagnosed with an ABF following aortic arch replacement, and an emergency TEVAR was performed. After adequate hemostasis, severe hypercapnia remained uncorrected despite the maximum ventilatory support. Thus, venovenous extracorporeal membrane oxygenation (VV ECMO) was immediately initiated, and severe respiratory acidosis improved dramatically. Furthermore, VV ECMO facilitated prompt bronchoscopic washout of the remaining blood clot without any danger of respiratory collapse and was weaned off successfully after 5 days as ventilation improved. This case demonstrates that emergency TEVAR in combination with VV ECMO can be a rescue strategy for massive hemoptysis from an ABF.

Impact of Left Heart Bypass on Arterial Oxygenation During One-Lung Ventilation for Thoracic Aortic Surgery.

OBJECTIVE: The aim of this study was to reveal the mechanism of improved arterial oxygenation by measuring the changes in oxygenation before and after initiation of left heart bypass (LHB) during one-lung ventilation (OLV) for thoracic aortic surgery. DESIGN: Prospective, observational study. SETTING: Single-institution, private hospital. PARTICIPANTS: The study comprised 50 patients who underwent aortic surgery via a left thoracotomy approach with LHB circulatory support. INTERVENTIONS: Patients were ventilated using pure oxygen during OLV, and the ventilator setting was left unchanged during the measurement period. MEASUREMENTS AND MAIN RESULTS: The measurement of partial pressure of arterial oxygen (PaO2) was made at the following 4 time points: 2 minutes after heparin infusion (point 1 [P1]), 2 minutes after inflow cannula insertion through the left pulmonary vein (P2), immediately before LHB initiation (P3), and 10 minutes after LHB initiation (P4). The mean±standard deviation (mmHg) of PaO2 measurements at the P1, P2, P3, and P4 time points were 244±121, 250±123, 419±122, and 430±109, respectively, with significant increases between P1 and P3, P1 and P4, P2 and P3, and P2 and P4 (p<0.0001, respectively). No significant increase in PaO2 was seen between P1 and P2 or between P3 and P4. CONCLUSIONS: The improved arterial oxygenation during OLV in patients who underwent thoracic aortic surgery using LHB can be attributed to the insertion of an inflow cannula via the left pulmonary vein into the left atrium before LHB.

Anesthetic Management of a Surgical Patient with Chronic Renal Tubular Acidosis Complicated by Subclinical Hypothyroidism.

A 53-year-old man with chronic renal tubular acidosis and subclinical hypothyroidism underwent lower leg amputation surgery under general anesthesia. Perioperative acid-base management in such patients poses many difficulties because both pathophysiologies have the potential to complicate the interpretation of capnometry and arterial blood gas analysis data; inappropriate correction of chronic metabolic acidosis may lead to postoperative respiratory deterioration. We discuss the management of perioperative acidosis in order to achieve successful weaning from mechanical ventilation and promise a complete recovery from anesthesia.

Skewing of peritoneal resident macrophages toward M1-like is involved in enhancement of inflammatory responses induced by secondary necrotic neutrophils in aged mice.

Secondary necrotic cells, which are generated if apoptotic cells are incompletely cleared, induce severe inflammatory responses involving MIP-2 production and subsequent neutrophil infiltration. Recently, we showed that the phagocytic capacity of peritoneal resident macrophages from wild type (WT) aged mice as well as SMP30(-/-) mice fed a VC-limited diet as to secondary necrotic cells was reduced as compared with that in young mice, and that the inflammatory responses induced were stronger than those in young mice, presumably because of the delay in removal of secondary necrotic cells in aged mice. In this study, we investigated why MIP-2 production was increased in aged mice upon injection of secondary necrotic cells and why the phagocytic capacity of peritoneal resident macrophages from aged mice was reduced. When cocultured with secondary necrotic cells, the peritoneal resident macrophages from both types of aged mice significantly produced MIP-2 even in the absence of IFN-γ, whereas MIP-2 production by macrophages from WT young mice required IFN-γ. The peritoneal resident macrophages from both types of aged mice expressed CD40, a M1 macrophage marker, as in the case of M1 macrophages, which were obtained by treatment of macrophages from WT young mice with IFN-γ and LPS. Furthermore, M1 macrophages exhibited less phagocytic capacity as to secondary necrotic cells than non-treated macrophages. These results suggest that the phenotype of peritoneal resident macrophages is skewed toward M1-like in aged mice and that such skewing toward M1-like is involved in enhancement of inflammatory responses induced by secondary necrotic neutrophils in aged mice.

Suppression of macrophage-mediated phagocytosis of apoptotic cells by soluble ß-glucan due to a failure of PKC-ßII translocation.

If apoptotic cells are not removed efficiently, they may proceed to the stage of secondary necrosis, which would cause inflammation. Therefore, identification of cause(s) and agent(s) for down-modulating phagocytosis of apoptotic cells would help understand the pathologies. In this study we found that macrophage-mediated phagocytosis of apoptotic cells was suppressed by both soluble and particulate ß-glucan. This suppression was not observed when secondary necrotic cells were used. The adhesion of apoptotic cells to macrophages was not suppressed by soluble ß-glucan, suggesting that soluble ß-glucan suppresses phagocytosis at a post-adhesion step. Experiments involving PKC inhibitors suggested that PKC-ßII is required for phagocytosis of apoptotic cells but not secondary necrotic ones by macrophages. Translocation of GFP-PKC-ßII from the cytoplasm to membranes occurred upon interaction with apoptotic cells but not secondary necrotic ones. Such translocation was inhibited by soluble ß-glucan. Overall, this study suggests that suppression of macrophage-mediated phagocytosis of apoptotic cells by soluble ß-glucan is due to a failure of PKC-ßII translocation.

Attenuated phagocytosis of secondary necrotic neutrophils by macrophages in aged and SMP30 knockout mice.

AIM: Secondary necrotic cells generated in vivo induce inflammatory responses; for example, the production of macrophage inflammatory protein-2 (MIP-2) and subsequent infiltration of neutrophils. The aim of the present study was to elucidate the effect of aging on the phagocytosis of secondary necrotic cells and the inflammatory responses by using either wild-type (WT) young mice, WT aged mice or senescence-accelerated mice (SMP30(-/-) mice). METHODS: The phagocytosis of secondary necrotic neutrophils with resident macrophage from either WT young mice, WT aged mice or SMP30(-/-) mice was examined by coculturing macrophages with secondary necrotic neutrophils in vitro. To investigate the inflammatory response induced by secondary necrotic cells, time-dependent infiltration of neutrophils and production of MIP-2 were determined in the peritoneal cavity on the injection of secondary necrotic cells. RESULTS: The phagocytosis of secondary necrotic cells by macrophages from WT aged and SMP30(-/-) mice was significantly reduced as compared with that by macrophages from WT young mice. On peritoneal injection of secondary necrotic cells, the peak time of neutrophil infiltration was earlier in SMP30(-/-) mice than in WT young mice. The number of neutrophils in SMP30(-/-) mice at the peak time was also greater than that in WT young mice. CONCLUSIONS: Our findings showed that the phagocytosis of secondary necrotic cells was attenuated in aged mice and SMP30(-/-) mice, and that the MIP-2 production was enhanced and subsequently neutrophil infiltration was exaggerated on peritoneal injection of secondary necrotic cells into those mice.

[Hyperthyroidism Diagnosed from Refractory Tachycardia and Hypotension during Surgery: A Case Report].

We report a case of hyperthyroidism diagnosed from refractory tachycardia and hypotension during surgery. Although the patient had exhibited tachycardia preop- eratively, it was difficult to suspect hyperthyroidism due to specific conditions of neurosurgical patient Eventually diagnosis of hyperthyroidism was made by exclusion, and prompt treatment was effectively initiated. Recently several reports suggested that landiolol was effective for rate control in patients with hyperthyroidism. At first intravenous bolus doses of landiolol were administered but were insufficient Secondly, intravenous propranolol was administered and tachycardia as well as blood pressure improved. The benefits of propranolol has been suggested.

Neutrophil biology: an update.

Neutrophil extracellular traps (NETs) are involved in bacterial killing as well as autoimmunity, because NETs contain proteases, bactericidal peptides, DNA and ribonucleoprotein. NETs are formed via a novel type of cell death called NETosis. NETosis is distinct from apoptosis, but it resembles necrosis in that both membranes are not intact so that they allow intracellular proteins to leak outside of the cells. Removal of NETs and neutrophils undergoing NETosis by phagocytes and its subsequent response are not completely clarified, as compared with the response after removal of either apoptotic or necrotic neutrophils by phagocytes. How neutrophil density in peripheral blood is kept within a certain range is important for health and disease. Although the studies on severe congenital neutropenia and benign ethnic neutropenia have provided unbiased views on it, the studies are rather limited to human neutropenia, and mice with a mutation of mouse counterpart gene often fail to exhibit neutropenia. Degranulation plays a critical role in bactericidal action. The recent studies revealed that it is also involved in immunomodulation, pain control and estrous cycle control. N1 and N2 are representative of neutrophil subpopulations. The dichotomy holds true in patients or mice with severe trauma or cancer, providing the basis of differential roles of neutrophils in diseases.

[Analgesia with paravertebral block for postoperative pain after thoracic or thoracoabdominal aortic aneurysm repair].

Paraplegia is a serious complication after thoracoabdominal aortic aneurysm repair. Therefore, maintenance of spinal cord perfusion pressure, drainage of cerebrospinal fluid, and avoidance of opioids are important for prevention of paraplegia Management of acute post-thoracotomy pain is necessary not only to keep the patient comfortable but also to minimize postoperative complications. However, epidural analgesia, a common method of pain control, is hard to use because of existing postoperative coagulopathy and avoidance of spinal cord ischemia Although both paravertebral block and epidural analgesia provide comparable pain relief after thoracic surgery, paravertebral block has lesser detrimental effects on spinal cord perfusion and better preserves the possibility to monitor neurologic function than epidural analgesia. We report 7 cases in which paravertebral blockade was used for analgesia in patients who underwent thoracoabdominal aneurysm repair.

Low levels of urinary liver-type fatty acid-binding protein may indicate a lack of kidney protection during aortic arch surgery requiring hypothermic circulatory arrest.

STUDY OBJECTIVE: To examine the change in liver-type fatty acid-binding protein (L-FABP) levels in patients undergoing aortic arch surgery and the correlation between L-FABP and postoperative acute kidney injury. DESIGN: Prospective observational study. SETTING: Operating room of a general hospital. PATIENTS: 36 adult patients. INTERVENTIONS AND MEASUREMENTS: Urine samples were obtained to measure urinary L-FABP at initiation of cardiopulmonary bypass (CPB) and 5 minutes after termination of hypothermic circulatory arrest. MAIN RESULTS: 22 (61.1%) patients developed acute kidney injury within a 48-hour period. L-FABP increases more than a thousand-fold were found. In patients who subsequently developed acute kidney injury, significant increases in L-FABP were noted from 2.9 (3.6) ng/mg of creatinine before CPB to 62.1 (995.6) ng/mg of creatinine 5 minutes after termination of circulatory arrest. Values in patients who did not develop acute kidney injury increased from 1.1 (5.7) ng/mg before CPB to 1133.0 (6358.8) ng/mg of creatinine showing a significant mean difference (P = 0.011). The area under the L-FABP receiver operating characteristic curve at 5 minutes after termination of circulatory arrest was 0.758. A cutoff value of 75.13 ng/mg of creatinine yielded both good sensitivity (1.000) and specificity (0.546) for detecting non-acute kidney injury. Patients who developed acute kidney injury after aortic arch surgery demonstrated lower levels of urinary L-FABP. CONCLUSIONS: Low levels of urinary L-FABP may indicate kidney injury and lack of renal protection.

The novel roles of neutrophils via opioid peptides: regulation of the estrous cycle and pain.

Neutrophils are excreted into the vaginal vault at metestrus during the estrous cycle, and this phenomenon has long been used to determine the phase of the estrous cycle. A much smaller number of neutrophils are also detected in the uterus and the ovary. Recently, we provided several lines of evidence supporting the notion that neutrophils infiltrate into the ovary to regulate the estrous cycle by opioid peptides. Upon inflammation, on the other hand, neutrophils infiltrate into the site of infection to suppress pain by opioid peptides. Thus, opioid peptides are key molecules by which neutrophils play a novel role in regulation of the pain and estrous cycle. In both cases, opioid peptides appear to be secreted by neutrophils stimulated with chemokines, such as MIP-2 and KC in mouse, corticotropin-releasing hormone and IL-1.

Integrin-αvß3 regulates thrombopoietin-mediated maintenance of hematopoietic stem cells.

Throughout life, one's blood supply depends on sustained division of hematopoietic stem cells (HSCs) for self-renewal and differentiation. Within the bone marrow microenvironment, an adhesion-dependent or -independent niche system regulates HSC function. Here we show that a novel adhesion-dependent mechanism via integrin-ß3 signaling contributes to HSC maintenance. Specific ligation of ß3-integrin on HSCs using an antibody or extracellular matrix protein prevented loss of long-term repopulating (LTR) activity during ex vivo culture. The actions required activation of αvß3-integrin "inside-out" signaling, which is dependent on thrombopoietin (TPO), an essential cytokine for activation of dormant HSCs. Subsequent "outside-in" signaling via phosphorylation of Tyr747 in the ß3-subunit cytoplasmic domain was indispensable for TPO-dependent, but not stem cell factor-dependent, LTR activity in HSCs in vivo. This was accompanied with enhanced expression of Vps72, Mll1, and Runx1, 3 factors known to be critical for maintaining HSC activity. Thus, our findings demonstrate a mechanistic link between ß3-integrin and TPO in HSCs, which may contribute to maintenance of LTR activity in vivo as well as during ex vivo culture.

Suppression of MIP-2 or IL-8 production by annexins A1 and A4 during coculturing of macrophages with late apoptotic human peripheral blood neutrophils.

Annexin A1 (ANXA1) is a well-known anti-inflammatory protein that is expressed on the surface of apoptotic cells. Annexin A4 (ANXA4) is also recruited from the nucleus to the cytoplasm in apoptotic cells, although it is not known whether or not ANXA4 is expressed on the surface of apoptotic cells. In this study, we obtained rabbit anti-human ANXA1 and ANXA4 antibodies, and then examined whether or not ANXA1 and ANXA4 are expressed on the surface of early and late human apoptotic cells. ANXA1 and, to a lesser extent, ANXA4 were detected on late but not early apoptotic HeLa cells, whereas ANXA1 and a small amount of ANXA4 were detected on both early and late apoptotic human neutrophils. We then examined the effects of the anti-human ANXA1 and ANXA4 antibodies on the mouse or human macrophage response to human apoptotic cells. Upon coculturing of mouse or human macrophages with late apoptotic human neutrophils, anti-human ANXA1 antibodies and, to a lesser extent, anti-human ANXA4 antibodies increased MIP-2 or IL-8 production significantly, suggesting that ANXA1 and ANXA4 suppress MIP-2 or IL-8 production by macrophages in response to late apoptotic human neutrophils.

Interleukin-9 receptor gene is transcriptionally regulated by nucleolin in T-cell lymphoma cells.

Interleukin-9 (IL-9) is a multifunctional cytokine that not only has roles in immune and inflammatory responses but also is involved in growth-promoting and anti-apoptotic activities in multiple transformed cell lines, which suggests a potential role in tumorigenesis. Over-expression of the receptor of IL-9 (IL-9R) occurs in several types of human leukemias and in radiation-induced mouse T-cell lymphoma (TL). The molecular mechanism that regulates transcription of the IL-9R gene (Il9r) during leukemogenesis is, however, not well understood. Using a mouse TL cell line that has high expression of Il9r, we sought to dissect its promoter structure. Here we show that the active promoter for Il9r is located in the 5'-flanking AT-rich region. Chromatin immunoprecipitation showed the opening of chromatin structure of the promoter region coupled with nucleolin binding in vivo. Immunohistochemical analysis confirmed the increased localization of nucleolin in the nuclei of TL cells. These data indicate that increased expression of Il9r is associated with an increased binding of nucleolin, coupled with chromatin opening, to an AT-rich region in the 5'-flanking region of Il9r in TL cells.

Acute kidney injury during aortic arch surgery under deep hypothermic circulatory arrest.

PURPOSE: The aim of this investigation was to describe the renal outcome and to identify risk factors for acute kidney injury (AKI), as defined by the Acute Kidney Injury Network (AKIN), during aortic arch surgery (AAS) under deep hypothermic circulatory arrest (DHCA). METHODS: A retrospective and observational study has been performed. One hundred thirty-five patients requiring AAS under DHCA were studied. RESULTS: Seventy-one patients (52.6%) developed AKI during the postoperative period. A logistic regression analysis identified three independent risk factors for AKI: preoperative hypertension (HT), emergency surgery, and duration of DHCA. Renal replacement therapy (RRT) was required in four patients (3.0%). The postoperative mortality rate among the patients with AKI was 2.8%, which was not statistically different from the rate of 1.6% observed in the non-AKI group (P = 0.62). CONCLUSIONS: A high incidence of AKI during AAS under DHCA was confirmed. Because AKI is highly associated with aortic surgery, novel approaches for protecting the kidneys other than deep hypothermia are needed. The logistic regression model identified HT, emergency surgery, and duration of DHCA as independent risk factors for AKI.

Mechanism underlying silent cleanup of apoptotic cells.

Apoptotic cells are cleared without an inflammatory response such as neutrophil infiltration. The mechanism underlying such silent cleanup of apoptotic cells has been intensively investigated in vitro for over a decade, and the concept that active suppression via IL-10, TGF-ß, and nitric oxide enables such silent cleanup to occur has been emerging. However, because this concept has not been vigorously examined under a variety of experimental conditions in vivo, the possibility remains that a null response, in which neither cytokines nor nitric oxide is produced upon an encounter with apoptotic cells, is responsible for silent cleanup.