Yoshihiro Ikura

Neutrophil Infiltration of Culprit Lesions in Acute Coronary Syndromes

Background—Neutrophils in unstable atherosclerotic lesions have not received much consideration, despite accumulating evidence suggesting a link between systemic inflammation and acute coronary syndromes. Methods and Results—Coronary artery segments were obtained at autopsy from 13 patients with acute myocardial infarction (AMI); 8 had a ruptured and 5 an eroded plaque. Patients (n=45) who had died of noncardiovascular diseases served as reference. Atherectomy specimens were obtained from 35 patients with stable angina pectoris (SAP) and from 32 patients with unstable angina pectoris (UAP). Antibodies against CD66b, elastase, myeloperoxidase, and CD11b identified neutrophils; CD10 identified neutral endopeptidase (NEP). CD66b-positive and NEP-positive neutrophils were counted and expressed as a number per square millimeter of tissue. All specimens with plaque rupture or erosion showed distinct neutrophil infiltration; the number did not differ between ruptured and eroded plaques. However, the number of NEP-positive neutrophils was significantly higher (P <0.0001) in ruptured plaques than in eroded plaques. UAP patients showed neutrophils in 14 of 32 culprit lesions; in SAP only 2 of 35 lesions contained neutrophils. The number of neutrophils and NEP-positive cells in patients with UAP was significantly higher (neutrophils, P <0.0005; NEP-positive cells, P <0.005) than in patients with SAP. Conclusions—The observations suggest that neutrophil infiltration is actively associated with acute coronary events. The high number of NEP-positive neutrophils in ruptured plaques, compared with eroded plaques, may reflect differences in the underlying pathophysiological mechanisms.

Telomere Shortening in Human Coronary Artery Diseases

Background—Increased cell turnover in response to injury is considered to be important in the development of atherosclerotic plaques. Telomere shortening has been shown to be associated with cell turnover. We assessed the telomere length of human coronary endothelial cells to clarify whether there is a relationship between telomere shortening and coronary artery disease (CAD). Methods and Results—Coronary endothelial cells were obtained from 11 patients with CAD who underwent autopsy and 22 patients without CAD who underwent autopsy by scraping off the luminal surface of coronary arteries. DNA extracted from the endothelial cells were blotted and hybridized with telomere-specific oligonucleotide ([TTAGGG]4). The hybridization signal intensity, which represented telomeric DNA content, was standardized with centromeric DNA content (T/C ratio) to estimate telomere length. The T/C ratios were significantly smaller (P <0.0001) in CAD patients than in age-matched non-CAD patients (CAD patients, 0.462±0.135; non-CAD patients, 1.002±0.212). In 6 individual CAD patients, the T/C ratio at the atherosclerotic lesion was significantly smaller (P <0.05) than that at the non-atherosclerotic portion. Conclusions—These findings suggest that focal replicative senescence and telomere shortening of endothelial cells may play a critical role in coronary atherogenesis and CAD.

Hypercoagulation and thrombophilia in liver disease

Summary.  A complex balance exists between endogenous procoagulants and the anticoagulant system in liver disease patients. Hypercoagulable events occur in cirrhosis patients despite the well‐known bleeding diathesis of liver disease. These events may be clinically evident, such as in portal vein thrombosis or pulmonary embolism, but these conditions may also be a silent contributor to certain disease states, such as portopulmonary hypertension or parenchymal extinction with liver atrophy as well as thrombosis of extracorporeal circuits in dialysis or liver assist devices. Moreover, liver disease‐related hypercoagulability may contribute to vascular disease in the increasingly common condition of non‐alcoholic fatty liver disease. Despite the incidence of these problems, there are few widely accessible and practical laboratory tests to evaluate the risk of a hypercoagulable event in cirrhosis patients. Furthermore, there is little research on the use of commonly accepted anticoagulants in patients with liver disease. This article is a result of an international symposium on coagulation disorders in liver disease and addresses several areas of specific interest in hypercoagulation in liver disease. Critical areas lacking clinical information are highlighted and future areas of research interest are defined with an aim to foster clinical research in this field.

Hepatocellular ballooning in NASH

BACKGROUND & AIMS Hepatocellular ballooning is a key finding in nonalcoholic steatohepatitis (NASH). It is conventionally defined by hemotoxylin and eosin (H&E) staining showing enlarged cells with rarefied cytoplasm and recently by changes in the cytoskeleton. Fat droplets are emerging as important organelles in cell metabolism. To address a possible relation between fat droplets and ballooning, we studied fat staining, H&E, and keratin 18 staining in human NASH. METHODS Sequential staining and high resolution imaging were used to study freshly prepared cryo-sections from 10 patients with histologically confirmed steatohepatitis using oil red O for fat droplet identification, H&E to identify ballooning, and anti-K18 to confirm cytoskeletal changes. High resolution images were captured at each stage using the Aperio Scanscope. To provide ultrastructural correlation, glutaraldehyde-fixed specimens were studied using transmission electron microscopy (TEM) with serial sectioning for localization of ballooned cells by light microscopy and TEM in identical specimens. RESULTS Serial staining consistently demonstrated that hepatocellular ballooning is associated with fat droplet accumulation evident by oil red O positivity and depletion of cytoplasmic keratin 18 with K-18 positive Mallory-Denk bodies (MDB). TEM confirmed the association between osmium stained fat droplets, MDB formation, and cellular enlargement and suggested droplet-associated dilation of the endoplasmic reticulum. CONCLUSIONS These results indicate a relationship between cellular ballooning, fat droplet accumulation, and cytoskeletal injury in NASH. We speculate that injury to multiple, organelles including fat droplets and endoplasmic reticulum, contribute to this characteristic finding.

Localization of oxidized phosphatidylcholine in nonalcoholic fatty liver disease: Impact on disease progression

Nonalcoholic steatohepatitis/nonalcoholic fatty liver disease is considered to be a hepatic manifestation of various metabolic disorders. However, its precise pathogenic mechanism is obscure. Oxidative stress and consequent lipid peroxidation seem to play a pivotal role in disease progression. In this study, we analyzed the localization of oxidized phosphatidylcholine (oxPC), a lipid peroxide that serves as a ligand for scavenger receptors, in livers of patients with this steatotic disorder. Specimens of non‐alcoholic fatty liver disease (15 autopsy livers with simple steatosis and 32 biopsy livers with steatohepatitis) were examined via immunohistochemistry and immunoelectron microscopy using a specific antibody against oxPC. In addition, scavenger receptor expression, hepatocyte apoptosis, iron deposition, and inflammatory cell infiltration in the diseased livers were also assessed. Oxidized phosphatidylcholine was mainly localized to steatotic hepatocytes and some macrophages/Kupffer cells. A few degenerative or apoptotic hepatocytes were also positive for oxPC. Immunoelectron microscopy showed oxPC localized to cytoplasmic/intracytoplasmic membranes including lipid droplets. Steatotic livers showed enhanced expression of scavenger receptors. The number of oxPC cells was correlated with disease severity and the number of myeloperoxidase‐positive neutrophils, but not with the degree of iron deposition. In conclusion, distinct localization of oxPC in liver tissues suggest that neutrophil myeloperoxidase‐derived oxidative stress may be crucial in the formation of oxPC and the progression of steatotic liver disease. (HEPATOLOGY 2006;43:506–514.)

Radiofrequency Ablation in a Porcine Lung Model: Correlation Between CT and Histopathologic Findings

OBJECTIVE The objective of our study was to investigate the time course changes of the ablated lesion after radiofrequency ablation in the porcine lung and the correlation between CT and histopathologic findings. CONCLUSION Ground-glass attenuation on CT led to overestimation of the size of necrotic lesions. The layered structural findings on CT were consistent with the histopathologic findings. Although CT findings reflect the histopathologic findings, attention should be paid to the dissociation of ablated lesions and high-density areas in clinical interpretation of CT images.

Persistent High Levels of Plasma Oxidized Low-Density Lipoprotein After Acute Myocardial Infarction Predict Stent Restenosis

Objective—Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to evaluate whether the 6-month outcome could be predicted by measuring plasma oxidized LDL (ox-LDL) levels at the time of hospital discharge. Methods and Results—Plasma ox-LDL levels were measured in 102 patients with AMI undergoing primary coronary stenting using a highly sensitive ELISA method. Measurements were taken on admission and at discharge, and the findings related to the clinical outcome. At 6-month follow-up, angiographic stent restenosis occurred in 25 (25%) of the 102 AMI patients. Plasma ox-LDL levels at discharge were significantly (P=0.0074) higher in the restenosis group than those in the no-restenosis group (1.03±0.65 versus 0.61±0.34 ng/5 &mgr;g LDL protein). Multiple regression analysis showed that only plasma ox-LDL levels at discharge were a statistically significant independent predictor for late lumen loss after stenting (&bgr;=0.645; P<0.0001). Conclusions—This prospective study demonstrates that persistence of an increased level of plasma ox-LDL at discharge is a strong independent predictor of stent restenosis at 6-month follow-up in AMI patients.

Pathophysiological role of oxidized low-density lipoprotein in plaque instability in coronary artery diseases

Oxidized low-density lipoprotein (ox-LDL) is considered to play a key role in the genesis of inflammatory processes in atherosclerotic lesions. It has also been shown that LDL isolated from patients with diabetes mellitus (DM) has an enhanced susceptibility to oxidation. Recently, a sandwich ELISA method for measurement of plasma ox-LDL levels has been developed. To elucidate the role of ox-LDL in plaque instability in coronary artery disease, we measured the plasma ox-LDL levels in patients with acute myocardial infarction (AMI), unstable angina pectoris (UAP), and stable angina pectoris (SAP), and moreover assessed whether a relationship is present between plasma ox-LDL levels and DM. We also measured the plasma ox-LDL level in a patient who died of AMI, thus enabling us to study the presence of ox-LDL and CD 36, which is one of the ox-LDL receptors, in the culprit lesion. Plasma ox-LDL levels were measured in 210 patients (AMI: 70, UAP: 70, SAP: 70), and in 55 control subjects. Plasma ox-LDL levels in AMI patients were significantly higher than in UAP patients (P<.0001), SAP patients (P<.0001), or controls (P<.0001). In the UAP group, plasma ox-LDL levels in patients with DM were significantly higher than those without DM (P<.005). The autopsied patient who died of AMI revealed an increased plasma level of ox-LDL, and immunohistochemically, the culprit coronary lesion contained abundant macrophage-derived foam cells, showing distinct positivity for ox-LDL and CD 36. These results strongly suggest an important role for ox-LDL in the genesis of plaque instability in human coronary atherosclerotic lesions.

Immunohistochemical Expression of Multidrug Resistance Proteins as a Predictor of Poor Response to Chemotherapy and Prognosis in Patients with Nodal Diffuse Large B-Cell Lymphoma

Background/Aims: The aim of this study was to determine whether expression of P-glycoprotein (P-gp), multidrug-resistance-related protein 1 (MRP1), and lung resistance protein (LRP) was related to the response to induction chemotherapy and prognosis in untreated diffuse large B-cell lymphoma (DLBCL). Methods: We assessed immunohistochemical expression of P-gp, MRP1 and LRP, using formalin-fixed and paraffin-embedded specimens of lymph node in 41 patients with DLBCL. Association between expression of these three proteins and their impact on clinical outcome and prognosis was statistically evaluated. Results: P-gp was positive in 37% of subjects, MRP1 in 63%, and LRP in 68%. The complete remission rates achieved in the group expressing these multidrug resistance (MDR) proteins was significantly lower than in the group not expressing them (20 versus 58%; p = 0.025 in P-gp, 23 versus 80%; p < 0.001 in MRP1 and 32 versus 69%, p = 0.043 in LRP, respectively). Furthermore, the patients expressing LRP had a shorter overall survival rate than those that did not (median of 26 months versus median not reached; p = 0.013). Conclusions: These findings suggest that the three MDR proteins are important predictive factors for the clinical outcome and prognosis in patients with DLBCL.

Neopterin is associated with plaque inflammation and destabilisation in human coronary atherosclerotic lesions

Background: Previous studies have shown that recent activation of the inflammatory response in coronary atherosclerotic lesions contributes to rapid progressive plaque destabilisation. Neopterin, a by-product of the guanosine triphosphate pathway, is produced by activated macrophages and serves as an activation marker for monocytes/macrophages. Objective: To elucidate the role of neopterin in coronary plaque destabilisation by immunohistochemical study of the presence of neopterin in coronary atherectomy specimens obtained from patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP). Patients and methods: All patients underwent atherectomy of the primary atherosclerotic lesions responsible for SAP (n = 25) and UAP (n = 25). Frozen samples were studied with antibodies against smooth muscle cells, macrophages, T cells, neutrophils and neopterin. Results: In 22/25 patients with UAP, abundant neopterin-positive macrophages were found at the sites of coronary culprit lesions. However, in 25 lesions from patients with SAP, only 11 lesions showed neopterin positivity. Quantitatively, the neopterin-positive macrophage score was significantly higher (p<0.001) in patients with UAP than in patients with SAP. Moreover, the neopterin-positive macrophage score showed a significant positive correlation with the number of neutrophils or T cells, respectively (neutrophils, r = 0.55, p<0.001; T cells, r = 0.70, p<0.001). Conclusions: Neopterin can be considered as one of the significant factors in the process of plaque inflammation and destabilisation in human coronary atherosclerotic lesions. Its exact role in the process needs to be investigated further.