Establishment of Epstein-Barr Virus (EBV) Latent Gene-Expressing T-Cell Lines with an Expression Vector Harboring EBV Nuclear Antigen 1.

Chronic active Epstein-Barr virus (EBV) infection (CAEBV) is characterized by chronic or recurrent infectious mononucleosis-like symptoms and is associated with EBV-associated T/natural killer (NK)-cell lymphoproliferative disorders, which frequently lead to the development of life-threatening complications, such as virus-associated hemophagocytic syndrome and EBV-positive apparent leukemia/lymphoma mainly in T- and NK-cell lineages. In order to clarify the EBV genes responsible for the diseases, we introduced the plasmid coding sequences of EBV-encoded small RNAs (EBERs) and/or latent membrane protein (LMP) 1 into human T-lymphocyte virus-I-negative human T-cell lines using a gene expression vector harboring EBV nuclear antigen 1, established the G418-resistant transformants of five T-cell lines, and quantitatively examined the expression of EBERs and LMP1 using real-time reverse transcriptase-polymerase chain reaction. The expression levels of EBERs in T-cell transformants with EBER DNA paralleled those in EBV-positive human T- and NK-cell lines, SNTK cells. The expression of LMP1 mRNA varied in SNTK cells and in human T-cell transformants, and the expression of LMP1 mRNA in T-cell lines expressing both EBERs and LMP1 was much lower than that in the same cell line expressing LMP1 mRNA alone. The currently employed gene expression system and currently obtained transformants may be useful for the analyses of the pathophysiology of CAEBV and EBV-positive T/NK-cell lymphoproliferative disorders.

Bystander CD8 + T cells may be involved in the acute phase of diffuse alveolar damage.

Acute respiratory distress syndrome (ARDS) is a serious complication of systemic inflammatory response syndrome, and diffuse alveolar damage (DAD) is a histological manifestation of ARDS. Endothelial cell injury is mainly responsible for ARDS. Many neutrophils and macrophages/monocytes, which are inflammatory cells that play a role in innate immunity, infiltrate the lung tissue in DAD. In recent years, it has become clear that CD8 plays an important role not only in the acquired immune system, but also in the innate immune system. Non-antigen-activated bystander CD8 + T cells express the unique granzyme B (GrB) + /CD25-/programmed cell death-1 (PD-1)-phenotype. The involvement of bystander CD8 + T cells in lung tissue in DAD is an unexplored field. This study aimed to determine whether bystander CD8 is involved in DAD. Twenty-three consecutive autopsy specimens were retrieved from patients with DAD, and the phenotypes of infiltrating lymphocytes in the DAD lesions were evaluated using immunohistochemistry. In most cases, the number of CD8 + T cells was higher than that of CD4 + T cells, and many GrB + cells were also observed. However, the number of CD25 + and PD-1 + cells was low. We conclude that bystander CD8 + T cells may be involved in cell injury during the development of DAD.

The ratio of CD163-positive macrophages to Iba1-positive macrophages is low in the intima in the early stage of cutaneous arteritis.

The etiology of polyarteritis nodosa (PAN) and localized PAN, including cutaneous arteritis (CA), remains unknown; however, initial endothelial damage has been implicated. The intima of the vasculitis lesions is predominantly infiltrated by innate-like bystander-activated CD8 T cells, in addition to the macrophages. Macrophages are among the major inflammatory cells involved in innate immunity and are classified into M1 and M2 subtypes. M1-type macrophages kill pathogens and cause inflammation, while M2-type macrophages promote the repair of tissues. Macrophage subtypes infiltrating in PAN and localized PAN vasculitis lesions have not yet been investigated. Innate immune response to a triggering factor on the endothelial cell surface may initiate CA pathogenesis. Thus, many M1-type macrophages may infiltrate in the intima during early CA. We assessed this hypothesis by immunohistochemical observation of macrophage phenotypes and polarization. Twenty-seven skin biopsy specimens from patients with CA were retrieved. Based on histology, we classified CA into four phases. The phenotypes of infiltrating macrophages in CA were evaluated by immunohistochemistry using antibodies against Iba-1, a pan-macrophage marker, and CD163, an M2-type macrophage marker. Our results showed that the ratio of CD163-positive M2-type macrophages to Iba1-positive macrophages was lower in the intima in the early stage of CA than in the later stage. In the media to adventitia, there was no significant difference in the ratios between these stages. These findings indicate that innate immunity is involved in the intima in the early stage of CA, suggesting that a trigger for CA might exist in endothelial cells.

An anaplastic pleomorphic xanthoastrocytoma with periventricular extension: An autopsy case report and review of the literature.

Pleomorphic xanthoastrocytomas (PXAs) are rare low-grade astrocytic tumors that typically present as superficial nodular cystic tumors of the cerebrum attached to the leptomeninx. Histologically, they are pleomorphic, hypercellular glial neoplasms. Despite the presence of microscopic pleomorphism, patients' postoperative prognosis is generally good. Anaplastic PXAs (APXAs) have a high mitotic index and patients with APXAs have a worse prognosis than patients with PXAs. Here, we report an autopsy case of APXA initially diagnosed as PXA. After gross total resection, the tumor recurred and was diagnosed as an APXA; thereafter, the patient died. An autopsy revealed that the tumor had relapsed at the primary site and had spread to the leptomeningeal space while concurrently invading the cerebrum including the periventricular area forming multifocal lesions. The histological findings of the autopsy were similar to those for epithelioid glioblastoma (EGBM) and small cell glioblastoma (SCGBM). In particular, the periventricular area with multifocal lesions was composed of SCGBM-like cells. It has been shown that multifocal lesions are frequently identified in patients with SCGBM. This is the first histopathologically confirmed case of APXA-related tumor presenting with periventricular extension and multifocal lesion formation. The periventricular extension might be a feature of PXAs and APXAs. However, suspected periventricular spread on imaging in past cases of PXAs and APXAs might instead represent the malignant transformation of these tumors to glioblastoma-like high-grade tumors, which often show SCGBM-like histological patterns.

Immunostaining With Immunoglobulin G Subclass Antibody Cocktail for Diagnosis of Type 1 Autoimmune Pancreatitis.

BACKGROUND.: Immunoglobulin (Ig) G4-related diseases (RDs) are systemic diseases in which serum IgG4 levels are frequently elevated. They can cause diffuse or focal tumor formation, organ swelling, and tissue thickening in organs infiltrated by IgG4+ plasma cells. The diagnostic criteria for IgG4-RDs include an IgG4/IgG ratio >40%, but counting IgG+ cells can be difficult because of the weakness of IgG staining density. We hypothesized that an antibody cocktail of mixed IgG1, IgG2, IgG3, and IgG4 (AC-IgG) might give immunohistochemistry results comparable with those of IgG in IgG4-RD. METHODS.: We compared AC-IgG reactivity with IgG expression in type 1 autoimmune pancreatitis (AIP), a representative IgG4-RD. We compared immunohistochemistry results using AC-IgG and IgG-only in 10 cases of AIP. The coefficient of variation (Cv) was used to analyze differences between AC-IgG and IgG findings in AIP by 13 board-certified pathologists. RESULTS.: Although mean values for IgG+ cells did not significantly differ between AC-IgG (34.3; range = 27.4-37.1) and IgG (30.0; range = 23.0-45.6; P = .6254), Cv was lower for AC-IgG (33.4%) than for IgG (51.4%; regression equation; y[IgG] = 0.988x + 0.982; correlation coefficient = 0.907). The data showed that the results of both methods were largely consistent. CONCLUSION.: AC-IgG could replace IgG to count IgG+ cells because of its lower Cv.

Ultrastructure of CIC-DUX4 sarcoma: the first pathological report.

CIC-DUX4 sarcoma (CDS) is a recently identified subtype of small round cell sarcoma. Morphologically, CDS partially resembles Ewing sarcoma (ES) and has been classified as "ES-like sarcoma"; however, detailed clinicopathologic and molecular genetic analyses have indicated that CDS is a new independent disease. Many studies have provided light microscopic, immunohistochemical, and genetic information about CDS. However, ultrastructural findings associated with this sarcoma are lacking. The aim of this study was to investigate the ultrastructure of CDS tumors and to compare their features with those of ES. We examined two cytogenetically confirmed CDS cases. We found that, compared to typical ES, CDS presented heterogeneity: in cell density, from tightly packed to loosely unconnected areas; in cell shape, from polygonal to pleomorphic with small processes; and in nuclear shape including round, oval, polygonal, elongated, invaginated, or wrinkled formations. However, abundant glycogen in the cytoplasm and rare cell adhesion apparatus between cells are major similarities between CDS and typical ES. Neuroendocrine granules, which are seen in rare ES cases, could not be identified in these two CDS cases. Although cytogenetic differences can validate a definite diagnosis, ultrastructural features could also provide important information about the differences between CDS and ES.

Histopathological findings of pregnancy-induced hypertension: histopathology of early-onset type reflects two-stage disorder theory.

The placental tissues of pregnancy-induced hypertension (PIH) patients exhibit multiple infarctions, acute atherosis, distal villous hypoplasia, and increased syncytial knots. However, these findings are not observed in all cases of PIH; thus, the significance of these changes in PIH is still unclear. We studied the frequency of histopathological changes of placental tissue in the subgroups of PIH, such as mild and severe PIH and early-onset (< 34 weeks) and late-onset (≥ 34 weeks) PIH. One hundred seven cases of PIH diagnosed at the Shinshu University Hospital, Matsumoto, Japan, between 2008 and 2014 were collected. PIH includes preeclampsia and gestational hypertension. The pathologic changes evaluated in the placenta were multiple infarctions, acute atherosis, distal villous hypoplasia, and increased syncytial knots. Placental tissues of patients with early-onset PIH demonstrated acute atherosis resulting from the incomplete remodeling of the spiral arteries and distal villous hypoplasia and increased syncytial knots reflecting placental hypoxia/ischemia much more frequently than those with late-onset PIH (all p < 0.001). The frequencies of multiple infarctions did not show a statistical difference between early-onset PIH and late-onset PIH. Moreover, there were no significant differences in the frequencies of histopathological features of placental tissue between mild PIH and severe PIH. Early-onset PIH exhibited histopathological changes of placental tissue consistent with the two-stage disorder theory more frequently than late-onset PIH. These findings support the idea that early-onset PIH and late-onset PIH are distinct entities or different extremes of the PIH spectrum.

Quantitative diagnosis of breast tumors by morphometric classification of microenvironmental myoepithelial cells using a machine learning approach.

Machine learning systems have recently received increased attention for their broad applications in several fields. In this study, we show for the first time that histological types of breast tumors can be classified using subtle morphological differences of microenvironmental myoepithelial cell nuclei without any direct information about neoplastic tumor cells. We quantitatively measured 11661 nuclei on the four histological types: normal cases, usual ductal hyperplasia and low/high grade ductal carcinoma in situ (DCIS). Using a machine learning system, we succeeded in classifying the four histological types with 90.9% accuracy. Electron microscopy observations suggested that the activity of typical myoepithelial cells in DCIS was lowered. Through these observations as well as meta-analytic database analyses, we developed a paracrine cross-talk-based biological mechanism of DCIS progressing to invasive cancer. Our observations support novel approaches in clinical computational diagnostics as well as in therapy development against progression.

Lipid-rich carcinoma of the breast that is strongly positive for estrogen receptor: a case report and literature review.

Lipid-rich carcinoma (LRC) of the breast is a rare breast cancer variant that accounts for <1% of all breast malignancies. It has been reported that LRCs are negative for estrogen receptor. Here, we report a case of LRC of the breast that was strongly positive for estrogen receptor and treated with endocrine adjuvant therapy. A 52-year-old postmenopausal female noticed a lump in her right breast by self-examination and presented to our hospital. Physical examination revealed an elastic 30 mm ×20 mm hard mass in the upper medial part of her right breast. The findings obtained using ultrasonography, mammography, and contrast-enhanced magnetic resonance imaging suggested breast cancer. Core needle biopsy resulted in the diagnosis of invasive carcinoma. The patient underwent mastectomy and sentinel lymph node biopsy. Histopathologically, the tumor cells were abundant in foamy cytoplasm. Because the presence of marked cytoplasmic lipid droplets was confirmed by Sudan IV staining and electron microscopic examination of the tumor and the lipid droplets were negative for periodic acid-Schiff staining, the tumor was diagnosed as an LRC. Immunohistochemically, estrogen and progesterone receptors of the tumor were strongly positive, human epidermal growth factor receptor type 2 was negative, and the ratio of Ki-67-positive cells was ~30%. After surgery, the patient underwent combination chemotherapy with anthracycline, cyclophosphamide, and 5-fluorouracil, followed by docetaxel. Thereafter, the pateint was treated with letrozole and has remained well for 24 months with no signs of recurrence.

Quantitative nucleic features are effective for discrimination of intraductal proliferative lesions of the breast.

BACKGROUND: Intraductal proliferative lesions (IDPLs) of the breast are recognized as a risk factor for subsequent invasive carcinoma development. Although opportunities for IDPL diagnosis have increased, these lesions are difficult to diagnose correctly, especially atypical ductal hyperplasia (ADH) and low-grade ductal carcinoma in situ (LG-DCIS). In order to define the difference between these lesions, many molecular pathological approaches have been performed. However, still we do not have a molecular marker and objective histological index about IDPLs of the breast. METHODS: We generated full digital pathology archives from 175 female IDPL patients, including usual ductal hyperplasia (UDH), ADH, LG-DCIS, intermediate-grade (IM)-DCIS, and high-grade (HG)-DCIS. After total 2,035,807 nucleic segmentations were extracted, we evaluated nuclear features using step-wise linear discriminant analysis (LDA) and a support vector machine. RESULTS: High diagnostic accuracy (81.8-99.3%) was achieved between pathologists' diagnoses and two-group LDA predictions from nucleic features for IDPL discrimination. Grouping of nuclear features as size and shape-related or intranuclear texture-related revealed that the latter group was more important when distinguishing between normal duct, UDH, ADH, and LG-DCIS. However, these two groups were equally important when discriminating between LG-DCIS and HG-DCIS. The Mahalanobis distances between each group showed that the smallest distance values occurred between LG-DCIS and IM-DCIS and between ADH and Normal. On the other hand, the distance value between ADH and LG-DCIS was larger than this distance. CONCLUSIONS: In this study, we have presented a practical and useful digital pathological method that incorporates nuclear morphological and textural features for IDPL prediction. We expect that this novel algorithm is used for the automated diagnosis assisting system for breast cancer.

A case of MUC5AC-positive intraductal neoplasm of the pancreas classified as an intraductal tubulopapillary neoplasm?

This report describes a unique case of intraductal tubulopapillary neoplasm (ITPN) of the pancreas in order to clarify its oncogenesis and more precisely classify pancreatic intraductal neoplasms. A 74-year-old man visited our institution for follow-up of acute pancreatitis. Imaging examinations revealed a hypovascular intraductal mass in the head of the pancreas with progressive dilation of the pancreatic duct, atrophy of the pancreatic parenchyma, and a non-mucinous appearance. A pancreatoduodenectomy was performed to identify this pancreatic intraductal neoplasm. Macroscopically, the tumor was a solid nodular mass with no visibly secreted mucin obstructing the dilated ducts. Histologically, it had a homogeneous appearance with nodules of back-to-back tubular glands and occasional papillary elements, and there were no apparent transitions to areas with less marked cytoarchitectural atypia. Although the intraductal neoplastic growth corresponded to an ITPN, immunohistochemical staining revealed partial positivity for MUC5AC, for which ITPNs are characteristically negative. Somatic mutations in KRAS, GNAS, BRAF, and PIK3CA were not detected. A loss of MUC5AC expression and mutations in KRAS and GNAS are key elements in the diagnosis of ITPN. Thus, it was difficult to distinguish the present case as a pancreatobiliary-type (PB-type) intraductal papillary mucinous neoplasm (IPMN) or a phenotypic variant of ITPN. As it is possible that some cases of PB-type IPMN and ITPN overlap, the precise classification of these rare lesions may require re-evaluation.

A primary pulmonary glomus tumor: a case report and review of the literature.

A case of a glomus tumor originating from the lung is reported. A 43-year-old female had undergone resection of a right lung tumor following a clinical diagnosis of carcinoid, sclerosing hemangioma, or other sarcoma. Histologically, the tumor comprised uniform small round to oval cells with centrally located nucleus, a clear cytoplasm, and apparent cell borders. The tumor also showed a focally hemangiopericytomatous pattern with irregularly branching or dilated vessels. Electron microscopy revealed smooth muscle differentiation of the tumor cells. Immunostaining further revealed that the tumor cells expressed smooth muscle actin, h-caldesmon, muscle specific actin (HHF-35), but not cytokeratin, epithelial membrane antigen, synaptophysin, or chromogranin A. Based on these findings, a diagnosis of primary pulmonary glomus tumor was established. Glomus tumors of the lung are very rare and only 21 cases have been reported to date. The histological features of the present tumor and the relevant literature are discussed.

Outcomes of endoscopic submucosal dissection for colorectal epithelial neoplasms in 200 consecutive cases.

BACKGROUND & AIMS: The clinical outcomes for endoscopic submucosal dissection (ESD), a novel endoluminal surgery for gastrointestinal neoplasm in the colorectum, are reported. METHODS: ESD was performed on 186 consecutive patients with 200 colorectal epithelial neoplasms who had preoperative diagnoses of mucosal or slight submucosally invasive neoplasms. In addition, these could be of large size, with submucosal fibrosis, or located on an intestinal fold. The therapeutic efficacy and safety were assessed. RESULTS: The targeted lesions consisted of 102 adenomas, 72 noninvasive carcinomas, and 26 invasive carcinomas. Seven lesions (3.5%) were histologically considered to be at substantial risk for nodal metastasis after ESD. The rate of en bloc resection was 91.5% (183/200), and en bloc resection with tumor-free lateral/basal margins (R0 resection) was 70.5% (141/200). Two lesions (1%) required emergency colonoscopies as a result of hematochezia after ESD. Eleven (5.5%) immediate perforations that occurred during ESD were successfully managed conservatively, but 1 (0.5%) delayed perforation required laparotomy. Two multiple-piece resections of 111 tumors (1.8%), which were successfully followed by colonoscopy (median follow-up, 18 months; range, 12-60 months), were found as locally recurrent tumors 2 and 21 months after ESD. No lymph node or distant metastasis was detected in 77 patients with noninvasive or invasive carcinoma (median follow-up, 24 months; range, 6-74 months). CONCLUSIONS: ESD is applicable in the colorectum with promising results. However, when considering the risks and benefits, piecemeal endoscopic resection or colorectal resection might be more appropriate for some subgroups of large flat neoplasms or those with submucosal fibrosis.

Technical feasibility of endoscopic submucosal dissection for gastric neoplasms in the elderly Japanese population.

BACKGROUND AND AIM: Endoscopic submucosal dissection (ESD) is gaining acceptance among endoscopists for its efficacy, especially in Japan. Elderly patients often have operative risk due to comorbid diseases, and the feasibility of this treatment for such patients should be investigated. The aim of this study is to evaluate the efficacy and safety of ESD in elderly patients. METHODS: Among 308 gastric neoplasms treated by ESD from 2000 to 2004 in one hospital, 49 lesions were discovered in 42 elderly patients who were 75 years of age or older. Indication criteria for ESD were gastric neoplasms with no apparent massive submucosal invasion diagnosed by endoscopy. The en bloc plus R0 resection rate and complications were assessed in comparison with younger patients. RESULTS: The average age of the patients was 78.9 years (range 75-88 years). Of these patients, 24 (57%) had comorbid diseases. The complete en bloc plus R0 resection rate was 96% (47/49). Postoperative bleeding requiring emergency endoscopy occurred in three patients (7%). Perforation during ESD occurred in one patient (2%), and was immediately closed with endoclips and managed by conservative medical treatment. The en bloc plus R0 resection rate and complication rate in elderly patients were not significantly different from those of younger patients. CONCLUSIONS: These results indicate that ESD could be a safe and reliable treatment for gastric neoplasms in elderly patients.

Submucosal injection of normal saline may prevent tissue damage from argon plasma coagulation: an experimental study using resected porcine esophagus, stomach, and colon.

Argon plasma coagulation (APC) is considered to be a safe thermocoagulation technique, but some reports show perforation and deformity during and after APC. In this study, we investigated the usefulness of prior submucosal injection for APC. APC over the mucosa was performed on fresh resected porcine esophagus, stomach, and colon with prior submucosal injection of normal saline (injection group) and without it (control group). The depth of tissue damage increased linearly with pulse duration up to the shallower submucosal layer in both groups. After that, tissue damage in the injection group remained confined to the shallower submucosal layer under any condition, whereas that in the control group continued to extend. The tissue damages of the injection groups were significantly (P<0.05) shallower than those of the control groups that reached the deeper submucosal layer in all the organs. Submucosal injection of normal saline before the application of APC may limit tissue damage and prevent perforation and deformity.

Safety of argon plasma coagulation for hemostasis during endoscopic mucosal resection.

Showing the safety of argon plasma coagulation (APC) over mucosal defects during/after endoscopic mucosal resection (EMR), 2 studies using resected pig (ex vivo) and living minipig (in vivo) stomachs were performed. As an ex vivo study, APC was applied over mucosal defects in 2 groups; with prior submucosal saline injection and without injection. Only subtle tissue damage was observed in the injection group, whereas apparent damage was observed in the noninjection group. The damaged distances in depth significantly increased as the pulse duration increased and those at the pulse duration of 4 seconds, which might be maximal in clinical practice, were approximately 1 mm. As an in vivo study, APC was applied over mucosal defects immediately after EMR. Only subtle tissue damage was observed even at the pulse duration of 20 seconds as shown in the ex vivo study. APC can be performed safely over the mucosal defects during/after EMR.

Endoscopic submucosal dissection of esophageal squamous cell neoplasms.

BACKGROUND & AIMS: Endoscopic submucosal dissection (ESD) has recently been developed for en bloc resection of stomach neoplasms, which results in high tumor eradication rates as well as a modality for the precise histologic assessment of the entire lesion. Application of the technique is desirable for esophageal squamous cell neoplasms (SCNs), but there have been no reports on the use of this procedure in the esophagus. METHODS: An ESD with methods similar to those used for resections of early gastric cancer was performed on 58 consecutive esophageal SCNs with preoperative diagnoses of intraepithelial neoplasm or intramucosal invasive carcinoma occurring in 43 enrolled patients. The therapeutic efficacy, complications, and follow-up results were assessed. RESULTS: The rate of en bloc resection was 100% (58/58), and en bloc resection with tumor-free lateral/basal margins (R0 resection) was 78% (45/58). There was no evidence of significant bleeding. Perforation occurred in 4 (6.9%) patients during the ESD, who were managed by conservative medical treatments after endoscopic closure of the perforation. Removal of 9 (16%) lesions resulted in esophageal stricture requiring balloon dilation after ESD. Of 40 lesions occurring in 31 patients fulfilling the criteria of node-negative tumors (mean follow-up, 17 months), 1 lesion resected by en bloc resection with nonevaluable tumor-free lateral margins (Rx [lateral] resection) recurred locally 6 months after ESD, which was treated successfully by a second ESD procedure. CONCLUSIONS: The ESD is applicable to the esophagus with promising results, but notification of risk is essential.

Successful outcomes of a novel endoscopic treatment for GI tumors: endoscopic submucosal dissection with a mixture of high-molecular-weight hyaluronic acid, glycerin, and sugar.

BACKGROUND: Endoscopic submucosal dissection (ESD) has recently been developed for endoscopic treatment of GI tumors, which enables us to resect even large tumors en bloc. However, a considerable frequency of perforation has become another problem. The best way to prevent perforation is to create a sufficient submucosal fluid cushion (SFC). The aim of this study is to find out the feasibility of ESD by using a mixture of 1900 KDa hyaluronic acid (Suvenyl) and a 10% glycerin plus 5% fructose solution (Glyceol). METHODS: Sixty-seven consecutive GI tumors in 54 patients who met indication criteria of ESD were enrolled. The mixing ratios of Suvenyl and Glyceol were 1:3 for esophageal/colorectal tumors and stomach tumors with scar, and 1:7 for stomach tumors without scar. After creation of SFCs, mucosal incision around the tumors and submucosal dissection under the tumors were made by cutting devices. The clinical outcomes were investigated. RESULTS: Mean resected and tumor sizes were 38.6 and 25.6 mm, respectively. Perforation occurred in one colon tumor with severe fibrosis (1.5%), which was managed by endoscopic clipping without salvage surgery. No blood transfusion was performed. In one stomach and in one rectal tumor (3%), endoscopic hemostasis was necessary because of postoperative bleeding. Overall endoscopic and histologic en bloc resection rates were 94% (63/67) and 78% (52/67), respectively, and there was no recurrence after follow-up of 1 year. CONCLUSIONS: ESD when using a mixture of Suvenyl and Glyceol results in excellent outcomes, and this injection solution should be used for ESD.

Tissue damage of different submucosal injection solutions for EMR.

BACKGROUND: When choosing submucosal injection solutions for EMR, tissue damage should be considered, as well as the lesion-lifting ability. The objective of the study was to find out the potential tissue damage of submucosal injection solutions. METHODS: The submucosal injection solutions examined were the following: normal saline solution (NS), 3.75% NaCl, 20% and 50% dextrose water (DW), a glycerin solution (Glyceol; 10% glycerin with 0.9% NaCl plus 5% fructose), and two hyaluronic acid (HA) solutions (0.25% 1900 kDa/NS solution and 0.125% 1900 kDa/ Glyceol solution). Furthermore, DW with different concentrations (5%, 10%, 15%, 30%, 40%) also was examined to find out the tolerable concentration without tissue damage. A total of 2 mL of each solution per stomach were injected by endoscopy into the submucosal layer at the separate sites of 4 living minipigs. Two minipigs were euthanized after 30 minutes of endoscopic observations, and the others were euthanized after additional endoscopic observations a week after injection. RESULTS: There was no apparent tissue damage in NS, 5% and 10% DW, Glyceol, or two solutions of HA, whereas, hypertonic solutions, except Glyceol and 10% DW, have more or less potency of tissue damage. In 3.75% NaCl and DW with concentrations of >or=20%, considerable tissue damage was observed, which might affect resected EMR specimens and ulcer healing. CONCLUSIONS: Use of hypertonic solutions except Glyceol is not recommended with respect to tissue damage. A combination of HA and Glyceol is the most favorable submucosal injection solution, considering tissue damage and lesion-lifting ability.