Hironori Kobayashi

C-C chemokine receptor 2 (CCR2) deficiency improves bleomycin-induced pulmonary fibrosis by attenuation of both macrophage infiltration and production of macrophage-derived matrix metalloproteinases

Macrophage infiltration is implicated in various types of pulmonary fibrosis. One important pathogenetic process associated with pulmonary fibrosis is injury to basement membranes by matrix metalloproteinases (MMPs) that are produced mainly by macrophages. In this study, C‐C chemokine receptor 2‐deficient (CCR2−/−) mice were used to explore the relationship between macrophage infiltration and MMP activity in the pathogenesis of pulmonary fibrosis, using the bleomycin‐induced model of this disease process. CCR2 is the main (if not only) receptor for monocyte chemoattractant protein‐1/C‐C chemokine ligand 2 (MCP‐1/CCL2), which is a critical mediator of macrophage trafficking, and CCR2 −/− mice demonstrate defective macrophage migration. Pulmonary fibrosis was induced in CCR2−/− and wild‐type (CCR2+/+) mice by intratracheal instillation of bleomycin. No significant differences in the total protein concentration in bronchoalveolar lavage (BAL) fluid, or in the degree of histological lung inflammation, were observed in the two groups until day 7. Between days 3 and 21, however, BAL fluid from CCR2−/− mice contained fewer macrophages than BAL fluid from CCR2+/+ mice. Gelatin zymography of BAL fluid and in situ zymography revealed reduced gelatinolytic activity in CCR2−/− mice. Immunocytochemical staining showed weaker expression of MMP‐2 and MMP‐9 in macrophages in BAL fluid from CCR2−/− mice at day 3. Gelatin zymography of protein extracted from alveolar macrophages showed reduced gelatinolytic activity of MMP‐2 and MMP‐9 in CCR2−/− mice. At days 14 and 21, lung remodelling and the hydroxyproline content of lung tissues were significantly reduced in CCR2−/− mice. These results suggest that the CCL2/CCR2 functional pathway is involved in the pathogenesis of bleomycin‐induced pulmonary fibrosis and that CCR2 deficiency may improve the outcome of this disease by regulating macrophage infiltration and macrophage‐derived MMP‐2 and MMP‐9 production. Copyright

Is diffusion-weighted magnetic resonance imaging superior to positron emission tomography with fludeoxyglucose F 18 in imaging non–small cell lung cancer?

OBJECTIVE This retrospective analysis examined whether diffusion-weighted magnetic resonance imaging might be as useful as positron emission tomography with fludeoxyglucose F 18 for (1) discriminating between non-small cell lung cancer and benign pulmonary nodules and (2) predicting aggressiveness of non-small cell lung cancer. METHODS Diffusion-weighted magnetic resonance imaging and positron emission tomography were performed before surgery in 110 patients with 124 pulmonary nodules smaller than 3 cm, including 96 non-small cell lung cancers and 28 benign nodules. Diffusion of water molecules in magnetic resonance imaging was measured by minimum value of apparent diffusion coefficient. The criterion standard was the result of histologic diagnosis or follow-up examination. Sensitivity and specificity for differentiating between cancers and benign nodules were compared between diffusion-weighted imaging and positron emission tomography. Apparent diffusion coefficient in diffusion-weighted imaging and fludeoxyglucose F 18 uptake in positron emission tomography were examined with respect to pathologic tumor stage; lymphatic, vascular and pleural involvements; and histologic differentiation. RESULTS There were no significant differences between diffusion-weighted magnetic resonance imaging and positron emission tomography in sensitivity or specificity for non-small cell lung cancer. Whereas positron emission tomography showed significant differences in fludeoxyglucose F 18 uptake between pathologic stages IA versus IB or more advanced stages; between tumors with and without lymphatic, vascular, or pleural involvement; and between well-differentiated and moderately or poorly differentiated adenocarcinomas (P <.01-0.001), no significant differences in apparent diffusion coefficient values in were observed. CONCLUSION Diffusion-weighted magnetic resonance imaging is equivalent to positron emission tomography in distinguishing non-small cell lung cancer from benign pulmonary nodules but is not as useful for predicting aggressiveness of non-small cell lung cancer.

Targeted Deletion of Class A Macrophage Scavenger Receptor Increases the Risk of Cardiac Rupture After Experimental Myocardial Infarction

Background— Class A macrophage scavenger receptor (SR-A) is a macrophage-restricted multifunctional molecule that optimizes the inflammatory response by modulation of the activity of inflammatory cytokines. This study was conducted with SR-A–deficient (SR-A−/−) mice to evaluate the relationship between SR-A and cardiac remodeling after myocardial infarction. Methods and Results— Experimental myocardial infarction (MI) was produced by ligation of the left coronary artery in SR-A−/− and wild-type (WT) male mice. The number of mice that died within 4 weeks after MI was significantly greater in SR-A−/− mice than in WT mice (P=0.03). Importantly, death caused by cardiac rupture within 1 week after MI was 31% (17 of 54 mice) in SR-A−/− mice and 12% (6 of 51 mice) in WT mice (P=0.01). In situ zymography demonstrated augmented gelatinolytic activity in the infarcted myocardium in SR-A−/− mice compared with WT mice. Real-time reverse transcription–polymerase chain reaction at day 3 after MI showed that the expression of matrix metalloproteinase-9 mRNA increased significantly in the infarcted myocardium in SR-A−/− mice compared with WT mice. Furthermore, SR-A−/− mice showed augmented expression of tumor necrosis factor-α and reduction of interleukin-10 in the infarcted myocardium at day 3 after MI. In vitro experiments also demonstrated increased tumor necrosis factor-α and decreased interleukin-10 expression in activated SR-A−/− macrophages. Conclusions— The present findings suggest that SR-A deficiency might cause impairment of infarct remodeling that results in cardiac rupture via insufficient production of interleukin-10 and enhanced expression of tumor necrosis factor-α and of matrix metalloproteinase-9. SR-A might contribute to the prevention of cardiac rupture after MI.

Quantification of the impact of segmentectomy on pulmonary function by perfusion single-photon-emission computed tomography and multidetector computed tomography

OBJECTIVE The impact of segmentectomy for preservation of pulmonary function was quantified by using a co-registered perfusion single-photon-emission computed tomography and multidetector computed tomography (SPECT/CT). METHODS Pulmonary function tests and perfusion SPECT/CT were conducted before and after segmentectomy in 56 patients. Actual values of forced expiratory volume in 1 second (FEV(1)) after segmentectomy were compared with the FEV(1) after virtual lobectomy, which was calculated by SPECT/CT. The preoperative and postoperative FEV(1) of each lobe that had undergone segmentectomy was measured by SPECT/CT. RESULTS The mean percent of FEV(1) preserved after segmentectomy was significantly higher than the value after virtual lobectomy (88% +/- 9% vs 77% +/- 7%; P < .001). Whereas the mean value of the preoperative FEV(1) of each lobe that was undergoing segmentectomy was 0.51+/-0.21 L, segmentectomy could preserve 41% +/- 24% of it. The FEV(1) of each lobe after the resection of more than three segments (n = 4) was preserved in 17% +/- 12% of the preoperative values, which was significantly less than 49% +/- 23% and 35% +/- 22% after the resection of one (n = 29) and two (n = 23) segments (P = .02 and .08, respectively). The FEV(1) of the left upper lobe after the upper division segmentectomy (n = 8) was preserved in 21% +/- 11% of the preoperative values, which was significantly less than 35% +/- 12% after the lingular segmentectomy (n = 7) (P = .03). CONCLUSION Segmentectomy can preserve the pulmonary function more significantly than lobectomy, except for the resection of more than three segments or the left upper division segmentectomy.

Prediction of pulmonary function after lung lobectomy by subsegments counting, computed tomography, single photon emission computed tomography and computed tomography: a comparative study

OBJECTIVE The aim of the present study was to determine the optimal method of predicting postoperative pulmonary function (PPF) after lung lobectomy. METHODS The forced expiratory volume in 1s (FEV(1)) was measured in 37 patients before and after lobectomy, and the following three methods of predicting the PPF were evaluated: (1) the number of functioning subsegments to be resected were counted (subsegments counting [SC]); (2) the volume of the functioning lung was calculated using CT images (quantitative CT); and (3) perfusion scintigraphy was performed using co-registered single photon emission computed tomography and CT imaging (SPECT/CT). The FEV(1) values predicted using these three methods were then compared with the measured postoperative FEV(1), and the correlations and differences were analyzed. RESULTS While a paired t-test showed the SPECT/CT method to have the smallest difference between the measured and the predicted FEV(1) values (0.05 l, p=0.33), followed by the quantitative CT method (0.07 l, p=0.07), and finally the SC method (0.15 l, p<0.001), the difference between the two values was not significantly different between the quantitative CT and SPECT/CT method (p=0.22). CONCLUSIONS While the SC method is inferior to both the quantitative CT and the SPECT/CT methods for predicting the PPF after lobectomy, the latter two methods are almost equally accurate.

Class A scavenger receptor (CD204) attenuates hyperoxia-induced lung injury by reducing oxidative stress.

To clarify the role of macrophage class A scavenger receptors (SR‐A, CD204) in oxidative lung injury, we examined lung tissue of SR‐A deficient (SR‐A−/−) and wild‐type (SR‐A+/+) mice in response to hyperoxic treatment. Protein levels of bronchoalveolar lavage fluid (BALF) and pulmonary oedema (wet : dry weight ratios) were higher in SR‐A−/− mice than those in SR‐A+/+ mice. Cumulative survival was significantly decreased in SR‐A−/− mice. However, there were no differences in BALF macrophage and neutrophil count between the two groups. Real‐time reverse transcriptase‐polymerase chain reaction (RT‐PCR) revealed that messenger RNA (mRNA) levels of the inducible nitric oxide synthase (iNOS) were increased during hyperoxic injury, and this increase was more prominent in SR‐A−/− mice. Expression levels of iNOS in alveolar macrophages after hyperoxia in vivo and in vitro were higher in SR‐A−/− macrophages compared with SR‐A+/+ macrophages. Immunohistochemistry using anti‐nitrotyrosine antibodies revealed distinctive oxidative stress in the injured lung in both groups, but it was more remarkable in the SR‐A−/− mice. After hyperoxic treatment, pulmonary mRNA levels of tumour necrosis factor‐α(TNF‐α) were elevated more rapidly in SR‐A−/− mice than in SR‐A+/+ mice. Together these results suggest that SR‐A expression attenuates hyperoxia‐induced lung injury by reducing macrophage activation. Copyright

MCP-1/CCR2 signalling pathway regulates hyperoxia-induced acute lung injury via nitric oxide production

To clarify the role of the monocyte chemoattractant protein‐1 (MCP‐1)/C–C chemokine receptor 2 (CCR2) signalling pathway in hyperoxia‐induced acute lung injury, CCR2‐deficient (CCR2−/−) and wild‐type (CCR2+/+) mice were exposed to 85% O2 for up to 6 days. At day 3, body weight significantly decreased and total protein concentration in bronchoalveolar lavage fluid (BALF) was higher in CCR2−/− mice compared with CCR2+/+ mice. Cumulative survivals were significantly lower in CCR2−/− mice than in CCR2+/+ mice. However, the two groups showed no significant differences in both histological changes and number of macrophages in BALF. Real‐time reverse transcriptase‐polymerase chain reaction revealed increased mRNA levels of MCP‐1, interleukin‐1β thioredoxin‐1, and inducible nitric oxide synthase (iNOS) in lung tissues in CCR2−/− mice compared with CCR2+/+ mice. Increased iNOS mRNA levels in alveolar macrophages exposed to 85% O2 for 48 h in vivo or in vitro were significantly higher in CCR2−/− mice than in CCR2+/+ mice. These results suggest that the MCP‐1/CCR2 signalling pathway is protective against hyperoxia‐induced tissue injury by suppressing induction of iNOS and consequent production of reactive oxygen species by activated alveolar macrophages.

Evaluation of Semiquantitative Assessments of Fluorodeoxyglucose Uptake on Positron Emission Tomography Scans for the Diagnosis of Pulmonary Malignancies 1 to 3 cm in Size

BACKGROUND To determine the optimal method of evaluating fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) for the diagnosis of pulmonary malignancies, the sensitivity and specificity of visual assessment and the several semiquantitative analyses were compared. METHODS Positron emission tomography data were analyzed for 130 pulmonary nodules from 1 to 3 cm in size (101 malignant and 29 benign nodules). The FDG uptake was measured by maximum standard uptake value (SUVmax), the contrast ratio (CR) of the SUV to the cerebellum (CR brain), and the CR of the SUV to the contralateral lung (CR lung). The CR lung was calculated from the SUV of the tumor (T) and that of the contralateral normal lung (N) and then was measured by two formulas, namely, T-N/T+N and T/N. RESULTS The sensitivities of both CR lung T-N/T+N and CR lung T/N were significantly higher than those of visual assessment, SUVmax, and CR brain (p = 0.01 to p < 0.001). No significant difference in sensitivity was observed between the CR lung T-N/T+N and CR lung T/N. Both CR lung T-N/T+N and CR lung T+N successfully imaged well-differentiated lung adenocarcinoma more frequently than the visual assessment, SUVmax, and CR brain (p = 0.002 to p < 0.001), whereas there were no significant differences of sensitivity among those five methods for the diagnosis of other histologic types of pulmonary malignancies. CONCLUSIONS The FDG uptake evaluated by the CR lung is superior to that evaluated using the visual assessment, SUVmax, and CR brain for the diagnosis of pulmonary malignancies, especially for well-differentiated lung adenocarcinoma. The simplified formula of CR lung with T/N can be used in place of that with T-N/T+N.

Size of Metastatic and Nonmetastatic Mediastinal Lymph Nodes in Non-small Cell Lung Cancer

Objective: To determine the optimum selection of mediastinal lymph nodes for biopsy in non-small cell lung cancer (NSCLC), lymph nodes with or without metastasis at each mediastinal station were ranked in size in patients with pathological N2 disease. Methods: Twenty-five NSCLC patients with pathological N2 disease who underwent pulmonary resection with complete mediastinal lymph node clearance were examined. Of 114 mediastinal lymph node stations dissected, 47 had metastases and 67 did not. The sizes of 259 nodes in the 47 positive lymph node stations were measured. Of these 259 nodes, 137 had metastases and 122 did not. The short- and long-axis diameters of the 259 lymph nodes were ranked in each lymph node station. Results: Mean short- and long-axis diameters of lymph nodes with metastases were significantly greater than those without (p < 0.001). In 47 metastatic lymph node stations, the short- and long-axis diameters were greatest in a metastatic node in 44 (94%) and 42 (89%) respectively, whereas in the remaining 3 (6%) and 5 (11%), the second largest but not the largest node was positive. None of the largest lymph nodes with metastasis were smaller than the second largest lymph node at each station. Four of the 10 patients with adenocarcinoma (40%) had metastasis in the second largest but not in the largest node measured by long-axis diameter, a significant difference from one in eight (12.5%) among the squamous cell carcinoma cases (p = 0.04). Conclusion: For mediastinal lymph node biopsy, both the largest and the second largest node at each station should be sampled, especially in adenocarcinoma. If only the largest lymph node is selected, false-negative results will occur at a rate of about 10%.

Microscopic-Sized “Microthymoma” in Patients With Myasthenia Gravis

BACKGROUND In 2005, Cheuk et al reported two patients with microscopic-sized thymomas and proposed the term microthymoma to distinguish it from the nodular hyperplasia of thymic epithelium, so-called microscopic thymoma. Here, we present microthymomas that were found in 196 patients with myasthenia gravis (MG) who had undergone thymectomy. MATERIALS AND METHODS Thymic tissues in 196 patients with MG who underwent thymectomy or thymothymomectomy were examined. Of these patients, 73 patients had thymoma indicated by CT before surgery, and the other 123 patients had no mediastinal tumors. From the resected thymic tissues, an average of 14 hematoxylin-eosin-stained sections (range, 4 to 55 sections) were prepared for microscopic examination. The histologic type of the thymoma was classified according to the World Health Organization (WHO) classification. RESULTS From the 196 patients, we found three microthymomas in 3 patients (1.5%). While these three tumors could not be seen grossly in pathology section, they were found microscopically (range, 2 to 4 mm). The histologic subtype according to the WHO classification system was B1 in one patient and B2 in two patients. CONCLUSION Microthymoma was found in 3 of 196 patients (1.5%) with MG. Microthymoma might exist in thymus of patients with MG, even in patients who have no thymoma indicated by CT.