Noriyasu Morikage

Ischemic Pre-Conditioning Enhances the Mobilization and Recruitment of Bone Marrow Stem Cells to Protect Against Ischemia/Reperfusion Injury in the Late Phase

OBJECTIVES The aim of this study was to investigate whether the mobilization and recruitment of bone marrow stem cells (BMSCs) contribute to cardioprotection in the late phase after ischemic pre-conditioning (IPC). BACKGROUND IPC is an innate phenomenon in which brief exposure to sublethal ischemia provides tissue protection from subsequent ischemia/reperfusion (I/R) injury. A delayed cardioprotection also occurs after IPC, but the precise mechanism is unclear. METHODS IPC was created with 4 cycles of 5-min occlusion and reperfusion of the abdominal aorta in mice. Heart I/R injury was induced by occluding the left anterior descending artery for 30 min immediately (early phase) or 24 h (late phase) after IPC. RESULTS Serum vascular endothelial growth factor and stromal cell-derived factor-1alpha levels were increased significantly 1 and 3 h after IPC, but CD34+ and CD34+/flk-1+ stem cells in the peripheral blood were increased significantly 12 and 24 h after IPC (p < 0.05). Compared with the control treatment, both the early and late phases of IPC protected the heart against I/R injury. However, the recruitment of BMSCs was significantly greater in the heart when I/R injury was induced in late phase than in the early phase of IPC (p < 0.01). Interestingly, the blockade of the recruitment of BMSCs significantly attenuated the cardioprotective effect of IPC in the late phase (p < 0.01) but did not change in the early phase. CONCLUSIONS Cardioprotection was observed in the early and late phases of IPC; however, the enhanced mobilization and recruitment of BMSCs played an important role in the late phase of IPC.

Cholesterol Primes Vascular Smooth Muscle to Induce Ca2 Sensitization Mediated by a Sphingosylphosphorylcholine–Rho-Kinase Pathway Possible Role for Membrane Raft

Hypercholesterolemia is a major risk factor involved in abnormal cardiovascular events. Rho-kinase–mediated Ca2+ sensitization of vascular smooth muscle (VSM) plays a critical role in vasospasm and hypertension. We recently identified sphingosylphosphorylcholine (SPC) and Src family tyrosine kinase (Src-TK) as upstream mediators for the Rho-kinase–mediated Ca2+ sensitization. Here we report the strong linkage between cholesterol and the Ca2+ sensitization of VSM mediated by a novel SPC/Src-TK/Rho-kinase pathway in both humans and rabbits. The extent of the sensitization correlated well with the total cholesterol or low-density lipoprotein cholesterol levels in serum. However, an inverse correlation with the serum level of high-density lipoprotein cholesterol was observed, and a correlation with other cardiovascular risk factors was nil. When cholesterol-lowering therapy was given to patients and rabbits with hypercholesterolemia, the SPC-induced contractions diminished. Depletion of VSM cholesterol by &bgr;-cyclodextrin resulted in a loss of membrane caveolin-1, a marker of cholesterol-enriched lipid raft, and inhibited the SPC-induced Ca2+ sensitization and translocation of Rho-kinase from cytosol to the cell membrane. Vasocontractions induced by membrane depolarization and by an adrenergic agonist were cholesterol-independent. Our data support the previously unreported concept that cholesterol potentiates the Ca2+ sensitization of VSM mediated by a SPC/Src-TK/Rho-kinase pathway, and are also compatible with a role for cholesterol-enriched membrane microdomain, a lipid raft. This process may play an important role in the development of abnormal vascular contractions in patients with hypercholesterolemia.

Is endovascular treatment of abdominal aortic aneurysms less invasive regarding the biological responses

To compare the biological responses following an endoluminal repair and a conventional open repair of abdominal aortic aneurysm (AAA), 14 patients who underwent an endoluminal repair (endograft group) and 26 who underwent an open repair (open group) were investigated. As markers of biological responses, interleukin-6 (IL-6) and -8 (IL-8), granulocyte elastase (GEL), white blood cell count (WBC), and serum C-reactive protein (CRP) were all measured preoperatively as well as on postoperative days (POD) 1, 3, and 6. In addition, the blood loss, duration of surgery, initial oral intake the day after surgery, and length of hospital stay were compared between both groups. The plasma levels of IL-6, GEL, CRP, and WBC were higher in the endograft group than in the open group, while the CRP, WBC, and GEL levels all peaked on POD 3. The plasma level of IL-6 remained high in the endograft group, compared with that in the open group throughout the study period. Conversely, blood loss, initial oral intake the day after surgery, and the length of hospital stay were all significantly greater in the open group than in the endograft group, although there was no significant difference in the duration of surgery between the two groups. These findings indicate that although the endoluminal repair of AAA is supposed to be less invasive, the biological responses tend to be greater because of the manipulation related to the insertion of the stent graft.

Periostin links mechanical strain to inflammation in abdominal aortic aneurysm.

Aims Abdominal aortic aneurysms (AAAs) are characterized by chronic inflammation, which contributes to the pathological remodeling of the extracellular matrix. Although mechanical stress has been suggested to promote inflammation in AAA, the molecular mechanism remains uncertain. Periostin is a matricellular protein known to respond to mechanical strain. The aim of this study was to elucidate the role of periostin in mechanotransduction in the pathogenesis of AAA. Methods and Results We found significant increases in periostin protein levels in the walls of human AAA specimens. Tissue localization of periostin was associated with inflammatory cell infiltration and destruction of elastic fibers. We examined whether mechanical strain could stimulate periostin expression in cultured rat vascular smooth muscle cells. Cells subjected to 20% uniaxial cyclic strains showed significant increases in periostin protein expression, focal adhesion kinase (FAK) activation, and secretions of monocyte chemoattractant protein-1 (MCP-1) and the active form of matrix metalloproteinase (MMP)-2. These changes were largely abolished by a periostin-neutralizing antibody and by the FAK inhibitor, PF573228. Interestingly, inhibition of either periostin or FAK caused suppression of the other, indicating a positive feedback loop. In human AAA tissues in ex vivo culture, MCP-1 secretion was dramatically suppressed by PF573228. Moreover, in vivo, periaortic application of recombinant periostin in mice led to FAK activation and MCP-1 upregulation in the aortic walls, which resulted in marked cellular infiltration. Conclusion Our findings indicated that periostin plays an important role in mechanotransduction that maintains inflammation via FAK activation in AAA.

Lysyl oxidase resolves inflammation by reducing monocyte chemoattractant protein-1 in abdominal aortic aneurysm

Lysyl oxidase (LOX) is an enzyme critical for the stability of extracellular matrix and also known to have diverse biological functions. Little is known, however, about the role of LOX in regulating inflammation. Here we demonstrate that LOX suppresses secretion of monocyte chemoattractant protein-1 (MCP-1) in cultured vascular smooth muscle cells. Furthermore, enhancement of LOX activity reduces MCP-1 in a mouse model of abdominal aortic aneurysm (AAA), thereby preventing macrophage infiltration and AAA progression. These findings suggest that LOX has a novel function in resolving inflammation by reducing MCP-1 in AAA.

Significance of Ultrasound Examination of Skin and Subcutaneous Tissue in Secondary Lower Extremity Lymphedema

OBJECTIVES To clarify whether ultrasound findings of skin and subcutaneous tissue represent the severity of lymphedema. MATERIALS AND METHODS Thirty-five patients with secondary lower extremity lymphedema caused by intrapelvic lymph node dissection during cancer surgery, who first visited our clinic between April 2009 and March 2012, were studied retrospectively. At their first visit, skin thickness, subcutaneous tissue thickness, and subcutaneous echogenicity were assessed at 8 points on the thigh and leg of both legs using an 11-MHz ultrasound transducer. These findings correlated with the International Society of Lymphology (ISL) clinical stage. RESULTS Skin thickness, subcutaneous tissue thickness, and subcutaneous echogenicity all showed significant positive correlation with the ISL stage. However, measuring skin and subcutaneous tissue thicknesses was not feasible in 29%-71% of scanning points in stage III legs because of poor delineation of boundaries at the dermo-hypodermal junction and the upper boundary of the muscular fascia. However, subcutaneous echogenicity was assessable at all scanning points and was linearly correlated with ISL stage. CONCLUSION Evaluating subcutaneous echogenicity is feasible even with low-resolution ultrasound and reflects the ISL stage. These findings may thus be valuable to objectively represent the severity of extremity lymphedema.

Inhibitory Effect of Statins on Inflammation-Related Pathways in Human Abdominal Aortic Aneurysm Tissue

HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitors (statins) have been suggested to attenuate abdominal aortic aneurysm (AAA) growth. However, the effects of statins in human AAA tissues are not fully elucidated. The aim of this study was to investigate the direct effects of statins on proinflammatory molecules in human AAA walls in ex vivo culture. Simvastatin strongly inhibited the activation of nuclear factor (NF)-κB induced by tumor necrosis factor (TNF)-α in human AAA walls, but showed little effect on c-jun N-terminal kinase (JNK) activation. Simvastatin, as well as pitavastatin significantly reduced the secretion of matrix metalloproteinase (MMP)-9, monocyte chemoattractant protein (MCP)-2 and epithelial neutrophil-activating peptide (CXCL5) under both basal and TNF-α-stimulated conditions. Similar to statins, the Rac1 inhibitor NSC23766 significantly inhibited the activation of NF-κB, accompanied by a decreased secretion of MMP-9, MCP-2 and CXCL5. Moreover, the effect of simvastatin and the JNK inhibitor SP600125 was additive in inhibiting the secretion of MMP-9, MCP-2 and CXCL5. These findings indicate that statins preferentially inhibit the Rac1/NF-κB pathway to suppress MMP-9 and chemokine secretion in human AAA, suggesting a mechanism for the potential effect of statins in attenuating AAA progression.

Tenascin-C is expressed in abdominal aortic aneurysm tissue with an active degradation process.

Abdominal aortic aneurysm (AAA) is a common disease caused by segmental weakening of the aortic walls and progressive aortic dilation leading to the eventual rupture of the aorta. Currently no biomarkers have been established to indicate the disease status of AAA. Tenascin‐C (TN‐C) is a matricellular protein that is synthesized under pathological conditions. In the current study, we related TN‐C expression to the clinical course and the histopathology of AAA to investigate whether the pattern of TN‐C expression could indicate the status of AAA. We found that TN‐C and matrix metalloproteinase (MMP)‐9 were highly expressed in human AAA. In individual human AAA TN‐C deposition associated with the tissue destruction, overlapped mainly with the smooth muscle actin‐positive cells, and showed a pattern distinct from macrophages and MMP‐9. In the mouse model of AAA high TN‐C expression was associated with rapid expansion of the AAA diameter. Histological analysis revealed that TN‐C was produced mainly by vascular smooth muscle cells and was deposited in the medial layer of the aorta during tissue inflammation and excessive destructive activities. Our findings suggest that TN‐C may be a useful biomarker for indicating the pathological status of smooth muscle cells and interstitial cells in AAA.

Fatal Diffuse Atheromatous Embolization Following Endovascular Grafting for an Abdominal Aortic Aneurysm : Report of a Case

Abstract A 78-year-old woman with an abdominal aortic aneurysm, 57 mm in diameter, was admitted to our hospital for endovascular grafting. Preoperative computed tomography and angiography showed friable mural thrombus in the suprarenal and infrarenal aorta, and a diagnosis of shaggy aorta was made. Postoperatively, the patient suffered cerebral infarction, and disseminated intravascular coagulopathy with multiple organ failure developed, resulting in early death on the third day after surgery. An autopsy revealed diffuse atheromatous embolization into the celiac, superior mesenteric, bilateral renal, bilateral hypogastric (trash buttock), and peripheral arteries. This case report serves to demonstrate that an abdominal aortic aneurysm with a shaggy aorta in the proximal neck is a contraindication to endovascular grafting, and that predicting the possibility of diffuse atheromatous embolization by detecting a shaggy aorta is the best way to prevent this catastrophic complication.

Subcutaneous Tissue Ultrasonography in Legs with Dependent Edema and Secondary Lymphedema

OBJECTIVES To elucidate the differences in subcutaneous ultrasound findings between dependent edema (DE) and secondary lower extremity lymphedema (LE). MATERIALS AND METHODS Twenty legs in 10 patients with DE and 54 legs in 35 patients with LE, who first visited our clinic between April 2009 and December 2012, were studied retrospectively. Subcutaneous echogenicity and echo-free space (EFS) were assessed at 8 points on the thigh and leg using an 8-12 MHz ultrasound transducer. RESULTS In DE, echogenicity was increased most in the lower leg, without a difference between the medial and lateral side. The EFS was most remarkable in the lower leg, and the lateral side was more severe. In the early stages of LE, echogenicity was similarly increased in the medial thigh and in the leg, while remarkable EFS was observed only in the lower leg. As clinical severity progressed, echogenicity increased in all parts of the lower extremity. EFS also increased in all parts of the leg, but the lower leg was still the most severe. CONCLUSION Echogenicity seemed to progress differently in DE and LE, but EFS progressed similarly and according to gravity. The current ultrasound findings may have added some diagnostic value in differentiating these conditions.