Mikiko Takahashi

Hydrogen therapy attenuates irradiation-induced lung damage by reducing oxidative stress

Molecular hydrogen (H(2)) is an efficient antioxidant that diffuses rapidly across cell membranes, reduces reactive oxygen species (ROS), such as hydroxyl radicals and peroxynitrite, and suppresses oxidative stress-induced injury in several organs. ROS have been implicated in radiation-induced damage to lungs. Because prompt elimination of irradiation-induced ROS should protect lung tissue from damaging effects of irradiation, we investigated the possibility that H(2) could serve as a radioprotector in the lung. Cells of the human lung epithelial cell line A549 received 10 Gy irradiation with or without H(2) treatment via H(2)-rich PBS or medium. We studied the possible radioprotective effects of H(2) by analyzing ROS and cell damage. Also, C57BL/6J female mice received 15 Gy irradiation to the thorax. Treatment groups inhaled 3% H(2) gas and drank H(2)-enriched water. We evaluated acute and late-irradiation lung damage after H(2) treatment. H(2) reduced the amount of irradiation-induced ROS in A549 cells, as shown by electron spin resonance and fluorescent indicator signals. H(2) also reduced cell damage, measured as levels of oxidative stress and apoptotic markers, and improved cell viability. Within 1 wk after whole thorax irradiation, immunohistochemistry and immunoblotting showed that H(2) treatment reduced oxidative stress and apoptosis, measures of acute damage, in the lungs of mice. At 5 mo after irradiation, chest computed tomography, Ashcroft scores, and type III collagen deposition demonstrated that H(2) treatment reduced lung fibrosis (late damage). This study thus demonstrated that H(2) treatment is valuable for protection against irradiation lung damage with no known toxicity.

Inhibition of matrix metalloproteinases reduces ischemia-reperfusion acute kidney injury.

Matrix metalloproteinases (MMPs) are endopeptidases that degrade extracellular matrix and involved in ischemic organ injuries. The present study was designed to determine the role of MMP-2 in the development of ischemic acute kidney injury (AKI). AKI was induced in MMP-2 wild-type (MMP-2+/+) mice by 30, 60, 90, and 120 min renal ischemia and reperfusion. Renal histology, expression and activity of MMP-2 and MMP-9, and renal function were examined during the development of AKI. AKI was also induced in MMP-2-deficient (MMP-2−/−) mice and MMP-2+/+ mice treated with inhibitor of MMPs (minocycline and synthetic peptide MMP inhibitor). In MMP-2+/+ mice, MMP-2 and MMP-9 activities increased significantly at 2 to 24 h, peaked at 6 h, after reperfusion. Immunohistochemical analysis identified MMP-2 in the interstitium around tubules and peritubular capillaries in the outer medulla. Acute tubular injury (ATI), including apoptosis and necrosis, was evident in the outer medulla at 24 h, along with renal dysfunction. As ischemia period increases, MMP-2 and MMP-9 activities at 6 h and severity of AKI at 24 h increased depending on the duration of ischemia between 30 and 120 min. However, the kidneys of MMP-2−/− mice showed minimal ATI; serum creatinine 24 h after reperfusion was significantly low in these mice. Inhibitors of MMPs reduced ATI and improved renal dysfunction at 24 h. We conclude that MMPs, especially MMP-2 have a pathogenic role in ischemia-reperfusion AKI, and that inhibitors of MMPs can protect against ischemic AKI.

Two forms of diffuse alveolar damage in the lungs of patients with acute respiratory distress syndrome

Acute respiratory distress syndrome is a severe disease, the treatment and pathophysiology of which are not completely established. The pathology of acute respiratory distress syndrome involves diffuse alveolar damage, which comprises severe alveolar epithelial cell damage, hyaline membrane formation, and festinate myofibroblast proliferation and fibrosis in the intra-alveolar spaces. We performed a clinicopathologic investigation of 26 autopsy cases of diffuse alveolar damage. Three cases of them were diagnosed as acute interstitial pneumonia that is idiopathic illness and resembles pathologically organizing diffuse alveolar damage. Immunohistochemical staining for types I and IV collagen, alpha-smooth muscle actin, and Ki-67 was carried out, and the sites of myofibroblast proliferation and type I collagen production were examined. All diffuse alveolar damage cases in the proliferative phase showed intra-alveolar myofibroblast proliferation. When diffuse alveolar damage was diagnosed pathologically as being due to severe infection, all 7 patients showed multiple organ dysfunction syndrome, whereas only 2 of 7 patients showed interstitial myofibroblast proliferation. When diffuse alveolar damage was attributed to tumor treatment with chemotherapy or to drug toxicity, 3 of 16 patients showed multiple organ dysfunction syndrome; 15 of 16 showed interstitial myofibroblast proliferation, 3 of 3 acute interstitial pneumonia patients did not show multiple organ dysfunction syndrome; and 3 of 3 acute interstitial pneumonia showed marked interstitial myofibroblast proliferation. These results suggest that the pathophysiologic mechanism of diffuse alveolar damage caused by severe infection is one of systemic circulation disturbance, although the mechanism underlying diffuse alveolar damage due to tumor with chemotherapy or drug toxicity appears to involve interstitial pneumonia-like lesions that are similar to acute interstitial pneumonia.

Role of survivin in acute lung injury: epithelial cells of mice and humans

Survivin, an inhibitor of apoptosis, regulates cell division and is a potential target for anticancer drugs because many cancers express high survivin levels. However, whether survivin would be toxic to human lung cells and tissues has not been determined. This report clarified the involvement of survivin in acute lung injury. We used immunohistochemical analysis, immunoelectron microscopy, and real-time reverse transcription-quantitative polymerase chain reaction to study survivin expression and localization in injured mouse and human lungs. We also used cultured human lung epithelial cells (BEAS-2B and A549) to study survivin cytoprotection. Nuclei and cytoplasm of epithelial cells in day 3 and day 7 models of bleomycin-injured lung showed survivin-positive results, which is consistent with upregulated survivin mRNA expression. These nuclei also evidenced double positive findings for proliferating cell nuclear antigen and survivin. Day 7 models had similar Smac/DIABLO-positive and survivin-positive cell distributions. The cytoplasm and nuclei of epithelial cells in lesions with diffuse alveolar damage manifested strong survivin-positive findings. Bleomycin stimulation in both epithelial cell lines upregulated expression of survivin and apoptosis-related molecules. Suppression of survivin expression with small interfering RNA rendered human lung epithelial cells susceptible to bleomycin-induced damage, with markedly upregulated activation of caspase-3, caspase-7, poly (ADP-ribose) polymerase, and lactate dehydrogenase activity and an increased number of dead cells compared with mock small interfering RNA-treated cells. Overexpression of survivin via transfection resulted in these epithelial cells being resistant to bleomycin-induced cell damage, with reduced activation of apoptosis-related molecules and lactate dehydrogenase activity and fewer dead cells compared with results for mock-transfected cells. Survivin, acting at the epithelial cell level that depends partly on apoptosis inhibition, is therefore a key mediator of cytoprotection in acute lung injury. Understanding the precise role of survivin in normal lung cells is required for the development of therapeutic survivin.

The difference of neovascularization in early intra-alveolar fibrosis between nonspecific interstitial pneumonia and usual interstitial pneumonia

Of the idiopathic interstitial pneumonias (IIPs), usual interstitial pneumonia (UIP) and diffuse alveolar damage (DAD) usually have poor prognoses. The prognoses of cryptogenic organizing pneumonia (COP) and nonspecific interstitial pneumonia (NSIP) are usually more favorable. Although several reports have described neovascularization in COP and UIP, this aspect of UIP has not been compared with NSIP. In this study, we evaluated neovascularization in intra‐alveolar fibrotic lesion of cases of fibrosing NSIP (f‐NSIP) (n = 26) and UIP (n = 25). In the f‐NSIP group, a considerable degree of neovascularization was observed compared to the UIP group and bud type intra‐alveolar fibrosis showed a greater degree of neovascularization compared to the mural‐incorporation and obliterative types of intra‐alveolar fibrosis. Real‐time reverse transcription polymerase chain reaction revealed a significantly greater expression of VEGF‐A mRNA in f‐NSIP than in UIP. The expression of matrix metalloproteinase‐2 (MMP‐2) mRNA also showed significantly higher in f‐NSIP than UIP. The greater VEGF‐A and MMP‐2 expression may play a role in the pathogenesis of neovascularization in early intra‐alveolar fibrotic lesions in f‐NSIP.

A Patient with Idiopathic Pleuroparenchymal Fibroelastosis Showing a Sustained Pulmonary Function due to Treatment with Pirfenidone.

The patient was a 68-year-old man presenting with body weight loss and exertional dyspnea. High-resolution computed tomography of the chest showed dense subpleural consolidation with traction bronchiectasis and volume loss predominantly in bilateral apical lesions and upper lobes. A histopathological analysis of a specimen of the right upper lobe showed histological patterns which were consistent with idiopathic pleuroparenchymal fibroelastotis (IPPFE). Treatment with pirfenidone was introduced with the expectation of its potential benefit. The effect of pirfenidone was satisfactory, and a decline in forced vital capacity was inhibited during treatment. This is the first case report suggesting the efficacy of pirfenidone for patients with IPPFE.

A mucin-rich variant of salivary duct carcinoma with a prominent mucinous component, a tumor that mimics mucinous adenocarcinoma

The mucin-rich variant of salivary duct carcinoma (mSDC) is a rare type of salivary duct carcinoma. mSDC usually has both conventional SDC and mucinous adenocarcinoma-like areas. This article describes a first case of mSDC in which 95% of the tumor consisted of a mucinous area without no solid conventional SDC, so that the tumor mimicked mucinous adenocarcinoma. A 55-year-old man was evaluated for a 14 mm mass in the left submandibular gland. The tumor showed that floating tumor nests in a prominent mucinous lake. Some floating tumor nests had focal cribriform pattern with comedo necrosis, and all tumor cells had immunoreactivity for androgen receptor, gross cystic disease fluid protein 15, and Her-2/neu. A diagnosis of mSDC was rendered. mSDC with prominent mucinous component sometimes resembles mucinous adenocarcinoma. Identifying specific histological and immunohistochemical features of floating tumor nests in the mucinous area are important for the diagnosis.

Renal Inflammatory Changes in Acute Hepatic Failure-Associated Acute Kidney Injury

Background/Aims: Acute kidney injury (AKI) is a common complication in advanced liver dysfunction. Our aim is to clarify the mechanisms of acute hepatic failure (AHF)-associated AKI. Methods: We examined the mechanisms of AHF-associated AKI, which is characterized by AKI in AHF and hyperbilirubinemia, following DA-to-Lewis rat liver transplantation. Results: During the progression of AHF and hyperbilirubinemia in liver graft rejection, AHF-associated AKI gradually developed by day 11. Degeneration and apoptotic cells were apparent in tubular epithelial cells with bile pigment accumulation and mitochondrial degeneration. Injury of peritubular capillaries (PTCs) was also noted with apoptotic endothelial cells, decreased expression of endothelial nitric oxide synthase, accumulation of α-smooth muscle actin+ pericytes and/or myofibroblasts, and inflammation. Angiogenic factors including vascular endothelial growth factor, angiopoietin-1, and angiopoietin-2 in the cortex were decreased on day 11. In addition, a marked reduction in the velocity of red blood cells in PTCs was evident in vivo. Conclusions: AHF-associated AKI seems to be mediated by renal tubular epithelial cell injury with bile pigment accumulation, impaired microcirculation caused by PTC endothelial cell injury with depletion of endothelial nitric oxide synthase and angiogenic factors, and by a decrease in RBC velocity and renal inflammation. Multiple mechanisms including tubular and PTC injuries and renal inflammation may be involved in the development of AHF-associated AKI.

Pulmonary Apical Opacities on Thin-Section Computed Tomography: Relationship to Primary Spontaneous Pneumothorax in Young Male Patients and Corresponding Histopathologic Findings

Objective The purpose of this study was to test the hypothesis that apical opacities on computed tomography (CT) are related to occurrence of primary spontaneous pneumothorax (PSP) in young male patients. Methods We compared the frequency of apical opacities on thin-section CT between 70 male patients with PSP (PSP group) and 74 male patients without a history of PSP (non-PSP group). We also evaluated histopathologic findings of 39 specimens from 37 surgical cases in the PSP group. Results Apical opacities were significantly more frequent in the PSP group than in the non-PSP group (right side, P = 0.01; left side, P = 0.005). Histopathologically, subpleural band-like alveolar collapse was seen in 35 specimens (89.7%), which was always accompanied by fibroelastosis and fibroblastic foci. Conclusions Apical opacities on CT were significantly associated with PSP in young male patients. These apical opacities histopathologically correspond to fibrotic pleural thickening with subpleural alveolar collapse.

Endophytic-Type Endometrial Cancer with Adenomyosis Successfully Diagnosed with Hysteroscopic Endometrial Biopsy Using an 8.3-mm Operative Resectoscope: A Case Report

In order to diagnose endometrial cancer preoperatively, outpatient endometrial biopsy with a curette is frequently performed owing to its convenience. However, in some cases, gynecologists fail to diagnose endometrial cancer via outpatient endometrial biopsy because of the cancer’s distribution in the uterus and its consistency. A 57-year-old Japanese woman (gravida 4 para 4) presented with a 6-month history of light but intermittent postmenopausal vaginal bleeding. A malignant uterine tumor was strongly suspected after imaging using ultrasound examination and magnetic resonance imaging; however, a precise pathological diagnosis was not achieved despite multiple outpatient endometrial biopsies with the aid of office hysteroscopy. Based on an endometrial biopsy obtained using a cutting loop electrode on an 8.3-mm operative resectoscope, we reached a diagnosis of endophytic-type endometrial cancer, which is in accordance with the final pathological diagnosis after abdominal hysterectomy. Three months after her first visit to our hospital, total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic/para-aortic lymph node dissection were performed. Macroscopically, the endometrium was atrophic, and there was no obvious mass in the uterine cavity; however, microscopically, the cancer cells mainly existed in the deep myometrium and the final diagnosis was International Federation of Gynecology and Obstetrics (FIGO) stage IB endometrial cancer. Operative biopsy of the uterine endometrium and deep myometrium using hysteroscopy confirmed an accurate preoperative diagnosis of uterine endometrial cancer specifically of the endophytic type.