C-kit Immunoreactivity Research Articles

Xiangbinfang granules enhance gastric antrum motility via intramuscular interstitial cells of Cajal in mice.

BACKGROUNDInterdigestive migrating motor complexes (MMC) produce periodic contractions in the gastrointestinal tract, but the exact mechanism of action still remains unclear. Intramuscular interstitial cells of Cajal (ICC-IM) participate in gastrointestinal hormone and neuromodulation, but the correlation between ICC-IM and MMC is also unclear. We found that xiangbinfang granules (XBF) mediated the phase III contraction of MMC. Here, the effects of XBF on gastric antrum motility in W/Wv mice and the effects of ICC-IM on gastric antrum MMC are reported.AIMTo observe the effects of ICC-IM on gastric antrum motility and to establish the mechanism of XBF in promoting gastric antrum motility.METHODSThe density of c-kit-positive ICC myenteric plexus (ICC-MP) and ICC-IM in the antral muscularis of W/Wv and wild-type (WT) mice was examined by confocal microscopy. The effects of XBF on gastric antrum slow waves in W/Wv and WT mice were recorded by intracellular amplification recording. Micro-strain-gauge force transducers were implanted into the gastric antrum to monitor the MMC and the effect of XBF on gastric antrum motility in conscious W/Wv and WT mice.RESULTSIn the gastric antrum of W/Wv mice, c-kit immunoreactivity was significantly reduced, and no ICC-IM network was observed. Spontaneous rhythmic slow waves also appeared in the antrum of W/Wv mice, but the amplitude of the antrum slow wave decreased significantly in W/Wv mice (22.62 ± 2.23 mV vs 2.92 ± 0.52 mV, P < 0.0001). MMCs were found in 7 of the 8 WT mice but no complete MMC cycle was found in W/Wv mice. The contractile frequency and amplitude index of the gastric antrum were significantly increased in conscious WT compared to W/Wv mice (frequency, 3.53 ± 0.18 cpm vs 1.28 ± 0.12 cpm; amplitude index, 23014.26 ± 1798.65 mV·20 min vs 3782.16 ± 407.13 mV·20 min; P < 0.0001). XBF depolarized smooth muscle cells of the gastric antrum in WT and W/Wv mice in a dose-dependent manner. Similarly, the gastric antrum motility in WT mice was significantly increased after treatment with XBF 5 mg (P < 0.05). Atropine (0.1 mg/kg) blocked the enhancement of XBF in WT and W/Wv mice completely, while tetrodotoxin (0.05 mg/kg) partially inhibited the enhancement by XBF.CONCLUSIONICC-IM participates in the regulation of gastric antrum MMC in mice. XBF induces MMC III-like contractions that enhance gastric antrum motility via ICC-IM in mice.

Structural Relationships Between Interstitial Cells of Cajal and Smooth Muscle Cells/Nerve Fibers in the Gastric Muscularis Mucosae of Chinese Giant Salamander.

Interstitial cells of Cajal (ICC) play an essential role in the motility of the gastrointestinal tract, and they have been identified in many laboratory animals and in humans. However, the information of ICC in lower animals is still very limited. In the present study, ICC were identified in the gastric muscularis mucosae of an amphibian—the Chinese giant salamander, by c-Kit immunohistochemistry and transmission electron microscopy. ICC showed c-Kit immunoreactivity and had spindle-shaped cell bodies and 1–2 long processes. ICC were located between smooth muscle cells (SMC) in gastric muscularis mucosae. Ultrastructurally, ICC appeared as polygon-, spindle-, and awl-shaped with long cytoplasmic prolongations between SMC. ICC had distinctive characteristics, such as nuclei with peripheral electron-dense heterochromatin, caveolae, and abundant intracytoplasmatic vacuoles, mitochondria, and rough endoplasmic reticula. Moreover, lamellar bodies and two types of condensed granules were observed in the cytoplasm of ICC. Notably, ICC establish close contacts with each other. Moreover, ICC establish gap junctions with SMC. In addition, ICC were frequently observed close to nerve fibers. In summary, the present study demonstrated the presence of ICC in the gastric muscularis mucosae of the Chinese giant salamander.

Metastatic Mixed Germ Cell Tumour with Embryonal Carcinoma and Choriocarcinoma in a Female Eurasian Harvest Mouse (Micromys minutus)

Mixed germ cell tumours occur rarely in veterinary species. This report describes a case of metastatic mixed germ cell tumour in a female Eurasian harvest mouse (Micromys minutus). The tumour was extensive in one ovary and the uterus, and was characterized by two distinct tumour cell populations with features typical of embryonal carcinoma (EC) and choriocarcinoma (CC). Metastases of CC to the lungs and liver were observed. The exact origin of the CC was unclear, but the possibility of a non-gestational CC is favoured, given the context of a mixed germ cell tumour and lack of p53 expression. EC diagnosis was confirmed by immunohistochemical labelling of CD30 and lack of immunoreactivity for c-Kit. In addition, membranous β-catenin expression was present in the EC component, indicating an inactive Wnt/β-catenin pathway, which is required for the maintenance of pluripotency.

Interstitial cells of Cajal in Wsh/Wsh c-kit mutant mice.

The c-Kit receptor tyrosine kinase regulates the development and differentiation of several progenitor cells. In the gastrointestinal (GI) tract, the c-Kit regulates the development of the interstitial cells of Cajal (ICC) that are responsible for motility regulation of the GI musculature. W-sash (Wsh) is an inversion mutation upstream of the c-kit promoter region that affects a key regulatory element, resulting in cell-type-specific altered gene expression, leading to a decrease in the number of mast cells, melanocytes, and ICC. We extensively examined the GI tract of Wsh/Wsh mice using immunohistochemistry and electron microscopy. Although the musculature of the Wsh/Wsh mice did not show any c-Kit immunoreactivity, we detected intensive immunoreactivity for transmembrane member 16A (TMEM16A, anoctamin-1), another ICC marker. TMEM16A immunopositive cells were observed as ICC-MY in the gastric corpus-antrum and the large intestine, ICC-DMP in the small intestine, and ICC-SM in the colon. Electron microscopic analysis revealed these cells as ICC from their ultrastructural features, such as numerous mitochondria and caveolae, and their close contact with nerve terminals. In the developmental period, we examined 14.5 and 18.5 day embryos but did not observe c-Kit immunoreactivity in the Wsh/Wsh small intestine. From this study, ICC subtypes developed and maturated structurally without c-Kit expression. Wsh/Wsh mice are a new model to investigate the effects of c-Kit and unknown signaling on ICC development and function.

1535 A Rare Case of Rectosigmoid Mucosal Schwann Cell Hamartoma

INTRODUCTION: Colorectal polyps of mesenchymal origin are rare. Mucosal Schwann cell hamartomas have a pure proliferation of Schwann cells in the lamina propria and show immunoreactivity to S-100 protein. To our knowledge, only 11 cases have been reported in the literature since it was first described in 2009. CASE DESCRIPTION/METHODS: We present a case of a 50-year-old African-American female who presented to us for routine screening colonoscopy. Her past medical history was only significant for a prolactinoma for which she was on cabergoline. The patient had no personal or family history of neural lesions or inherited syndromes such as NF1, Cowden syndrome or MEN 2B. The colonoscopy revealed a 2 mm polyp in the cecum and a 3 mm sized rectosigmoid polyp which were resected and sent to pathology. The cecal polyp showed a tubular adenoma. The pathology report for the rectosigmoid polyp was consistent with spindle-shaped lesional cells with immunohistochemical staining strongly positive for S-100. They did not have immunoreactivity for epithelial membrane antigen (EMA). Hence, supporting the diagnosis for Schwann cell hamartoma. The patient was made aware of pathology findings and reassured. DISCUSSION: Mucosal Schwann Cell Hamartoma is a rare and benign lesion that forms in the colon. It usually arises in older adults. The specific risk factors of Mucosal Schwann Cell Hamartoma are unknown. Most patients are asymptomatic however rectal schwannoma may cause symptoms such as obstruction, bleeding, and tenesmus. They are often found incidentally in the distal colon during a colonoscopy. These tumors are poorly circumscribed, with short fascicles of uniform spindle cells replacing the colonic lamina propria, especially the superficial lamina propria, and separating and entrapping the crypts. These tumors involve the mucosa but never the submucosa. Although the histological differential diagnosis of a mucosal Schwann-cell hamartoma can include a gastrointestinal stromal tumor (GIST), neurofibroma, mucosal neuroma, ganglioneuroma, or mucosal schwannoma, a mucosal Schwann-cell hamartoma is composed of single Schwann cells without other cells, such as axons or fibroblasts, and is uniformly stained for S-100. These cells do not have immunoreactivity for c-Kit, CD34, glial fibrillary acidic protein, epithelial membrane antigen (EMA), smooth muscle actin, or neurofilament protein (NFP). Due to the benign nature of Mucosal Schwann Cell Hamartoma, they do not generally require any treatment.

1611 Not All Polyps Are Created Equal: Schwann Cell Hamartoma Incidentally Found on Screening Colonoscopy

INTRODUCTION: Majority of colorectal polyps are epithelial in origin, such as adenomas (tubular, tubulovillous, and villous) and serrated polyps (hyperplastic, traditional serrated, sessile serrated). Mesenchymal polyps are rare, but detection is improving with high-quality screening colonoscopies. Mucosal Schwann cell hamartomas (MSCH) of the gastrointestinal tract are mesenchymal tumors that were first described in 2009. The median age at diagnosis is 59 years (range 34-88 years), with a slight female predominance. CASE DESCRIPTION/METHODS: A 70-year-old white male with coronary artery disease, persistent atrial fibrillation, and obstructive sleep apnea was referred for screening colonoscopy. This revealed 2 sessile polyps (Paris 0-1s) in the sigmoid colon, measuring 2 mm and 7 mm in size. The polyps were completely removed by cold biopsy polypectomy and cold snare polypectomy, respectively. The second polypectomy site oozed slightly and was closed using 2 hemoclips, with anticipation that the patient would be resuming anticoagulation the same day. Pathology of the polyps were consistent with mucosal Schwann cell hamartoma, staining positive for S-100 protein. DISCUSSION: MSCH are a group of neuronal polyps purely composed of Schwann cells that are positive for S-100 in a strong, diffuse pattern, with both nuclear and cytoplasmic staining. They typically cause no symptoms and may present as small polyps (1-8 mm) incidentally found during colonoscopy, predominantly in the rectosigmoid. They are not associated with any inherited syndromes. The diagnosis is made after excluding other lesions that resemble spindle cell proliferation and other neuronal tumors. These include neurofibroma, leiomyoma, and gastrointestinal stromal tumor (GIST). Neurofibromas, while also composed of Schwann cells, are often associated with neurofibromatosis type 1 (NF1). NF1 is usually accompanied by multiple cutaneous neurofibromas. Purely colorectal neurofibromas without skin manifestations are extremely rare. GIST can be easily excluded by negative immunoreactivity of c-Kit and CD117. Leiomyomas stain positive for smooth muscle actin. In summary, MSCH’s are rare lesions with a benign course and no known association with inherited polyposis syndromes. Diagnosis depends on pathology demonstrating lack of axons on pathology, and immunohistochemistry staining strongly for S-100 protein. Our case highlights that accurate diagnosis can prevent overly aggressive or unnecessary treatments.

C-Kit+ Cells in Adult Salivary Glands do not Function as Tissue Stem Cells

A rare population of salivary gland cells isolated based on c-Kit immunoreactivity are thought to represent tissue stem cells since they exhibit the most robust proliferative and differentiation capacity ex vivo. Despite their high promise for cell-based therapies aimed at restoring salivary function, the precise location and in vivo function of c-Kit+ stem cells remain unclear. Here, by combining immunostaining with c-KitCreERT2-based genetic labeling and lineage tracing in the adult mouse salivary glands, we show that c-Kit is expressed in a relatively large and heterogeneous cell population that consists mostly of differentiated cells. Moreover, c-Kit does not mark ductal stem cells that are known to express cytokeratin K14. Tracking the fate of in vivo-labeled c-Kit+ or that of K14+ cells in spheroid cultures reveals a limited proliferative potential for c-Kit+ cells and identifies K14+ cells as the major source of salispheres in these cultures. Long-term in vivo lineage tracing studies indicate that although c-Kit marks at least two discrete ductal cell lineages, c-Kit+ cells do not contribute to the normal maintenance of any other cell lineages. Our results indicate that c-Kit is not a reliable marker for salivary gland stem cells, which has important implications for salivary gland regenerative therapies.

Disruption of the pacemaker activity of interstitial cells of Cajal via nitric oxide contributes to postoperative ileus.

Interstitial cells of Cajal (ICC) serve as intestinal pacemakers. Postoperative ileus (POI) is a gastrointestinal motility disorder that occurs following abdominal surgery, which is caused by inflammation-induced dysfunction of smooth muscles and enteric neurons. However, the participation of ICC in POI is not well understood. In this study, we investigated the functional changes of ICC in a mouse model of POI. Intestinal manipulation (IM) was performed to induce POI. At 24h or 48h after IM, the field potential of the intestinal tunica muscularis was investigated. Tissues were also examined by immunohistochemistry and electron microscopic analysis. Gastrointestinal transit was significantly decreased with intestinal tunica muscularis inflammation at 24h after IM, which was ameliorated at 48h after IM. The generation and propagation of pacemaker potentials were disrupted at 24h after IM and recovered to the control level at 48h after IM. ICC networks, detected by c-Kit immunoreactivity, were remarkably disrupted at 24h after IM. Electron microscopic analysis revealed abnormal vacuoles in the ICC cytoplasm. Interestingly, the ICC networks recovered at 48h after IM. Administration of aminoguanidine, an inducible nitric oxide synthase inhibitor, suppressed the disruption of ICC networks. Ileal smooth muscle tissue cultured in the presence of nitric oxide donor, showed disrupted ICC networks. The generation and propagation of pacemaker potentials by ICC are disrupted via nitric oxide after IM, and this disruption may contribute to POI. When inflammation is ameliorated, ICC can recover their pacemaker function.

Changes in the interstitial cells of Cajal and neuronal nitric oxide synthase positive neuronal cells with aging in the esophagus of F344 rats.

The aging-associated cellular and molecular changes in esophagus have not been established, yet. Thus we evaluated histological structure, interstitial cells of Cajal (ICCs), neuronal nitric oxide synthase (nNOS)-positive cells, and contractility in the esophagus of Fischer 344 rat at different ages (6-, 31-, 74-weeks, and 2-years). The lamina propria thickness and endomysial area were calculated. The immunoreactivity of c-Kit, nNOS and protein gene product (PGP) 9.5 was counted after immunohistochemistry. Expression of c-Kit, stem cell factor (SCF), nNOS and PGP 9.5 mRNA was measured by real-time PCR, and expression of c-Kit and nNOS protein was detected by Western blot. Isovolumetric contractile force measurement and electrical field stimulation (EFS) were conducted. The lamina propria thickness increased (6 week vs 2 year, P = 0.005) and the endomysial area of longitudinal muscle decreased with aging (6 week vs 2 year, P<0.001), while endomysial area of circular muscle did not significantly decrease. The proportions of NOS-immunoreactive cells and c-Kit-immunoreactive areas declined with aging (6 week vs 2 year; P<0.001 and P = 0.004, respectively), but there was no significant change of PGP 9.5-immunopositiviy. The expressions of nNOS, c-Kit and SCF mRNA also reduced with aging (6 week vs 2 year; P = 0.006, P = 0.001 and P = 0.006, respectively), while the change of PGP 9.5 mRNA expression was not significant. Western blot showed the significant decreases of nNOS and c-Kit protein expression with aging (6 week vs 2 year; P = 0.008 and P = 0.012, respectively). The EFS-induced esophageal contractions significantly decreased in 2-yr-old rat compared with 6-wk-old rats, however, L-NG-Nitroarginine methylester did not significantly increase the spontaneous and EFS-induced contractions in the 6-wk- and 2-yr-old rat esophagus. In conclusion, an increase of lamina propria thickness, a decrease of endomysial area, c-Kit, SCF and NOS expression with preserved total enteric neurons, and contractility in aged rat esophagus may explain the aging-associated esophageal dysmotility.

Equine ocular mast cell tumor: histopathological and immunohistochemical description.

ABSTRACTThis report describes an ocular mast cell tumor in a 13-year-old female sport horse. Clinical examination revealed a solitary firm mass located in the ocular mucosa, protruding from behind the left lower eyelid. The lesion was surgically removed and submitted to histopathology. Microscopically, the mass was composed of sheets of well-differentiated neoplastic round cells circumscribed by delicate connective tissue. Positive Giemsa and Toluidine Blue staining confirmed the presence of cytoplasmic granules. Neoplastic cells showed strong membranous and mild diffuse cytoplasmic immunoreactivity for c-KIT and a low KI-67 proliferative index. Based on these findings, a diagnosis of ocular mast cell tumor was made. Six months after surgical removal, no evidence of ocular lesion recurrence was detected.

C-Kit signaling determines neointimal hyperplasia in arteriovenous fistulae.

Stenosis of arteriovenous (A-V) fistulae secondary to neointimal hyperplasia (NIH) compromises dialysis delivery, which worsens patients' quality of life and increases medical costs associated with the maintenance of vascular accesses. In the present study, we evaluated the role of the receptor tyrosine kinase c-Kit in A-V fistula neointima formation. Initially, c-Kit was found in the neointima and adventitia of human brachiobasilic fistulae, whereas it was barely detectable in control veins harvested at the time of access creation. Using the rat A-V fistula model to study venous vascular remodeling, we analyzed the spatial and temporal pattern of c-Kit expression in the fistula wall. Interestingly, c-Kit immunoreactivity increased with time after anastomosis, which concurred with the accumulation of cells in the venous intima. In addition, c-Kit expression in A-V fistulae was positively altered by chronic kidney failure conditions. Both blockade of c-Kit with imatinib mesylate (Gleevec) and inhibition of stem cell factor production with a specific short hairpin RNA prevented NIH in the outflow vein of experimental fistulae. In agreement with these data, impaired c-Kit activity compromised the development of NIH in A-V fistulae created in c-KitW/Wv mutant mice. These results suggest that targeting of the c-Kit signaling pathway may be an effective approach to prevent postoperative NIH in A-V fistulae.

Immunohistochemical identification of interstitial cells of cajal (ICCs) in prenatal bovine intestine

Interstitial cell of cajal (ICC) was detected using C-kit immunoreactivity in different regions of prenatal foetal intestine. The ICC was first detected as early as four months of foetal age. The ICC was bipolar to stellate shaped and mostly concentrated around myenteric plexus, innervating their fibers in the longitudinal and circular muscle layers. The number of ICC varied significantly in different regions of intestine. ICC at sub mucosal plexus was not detected in the small intestine but present in the large intestine. Highest population of ICC was detected at ceco-colic junction. We are the first worker to report the ontogenesis of ICC in prenatal bovine intestine. These results suggested the correlation of ICC related pathophysiology in adult.

Fat deposition in the tunica muscularis and decrease of interstitial cells of Cajal and nNOS-positive neuronal cells in the aged rat colon

Little is known about the time course of aging on interstitial cells of Cajal (ICC) of colon. The aim of this study was to investigate the change of morphology, ICC, and neuronal nitric oxide synthase (nNOS)-immunoreactive cells in the aged rat. The proximal colon of 344 Fischer rats at four different ages (6, 31, 74 wk, and 2 yr) were studied. The immunoreactivity of c-Kit, nNOS, anti-protein gene product 9.5, and synaptophysin were counted after immunohistochemistry. The c-kit, stem cell factor (ligand of Kit), and nNOS mRNA were measured by real-time PCR. c-Kit and nNOS protein were assessed by Western blot. Isovolumetric contractile force measurement and electrical field stimulation (EFS) were conducted. The area of intramuscular fat deposition significantly increased with age after 31 wk. c-Kit-immunoreactive ICC and nNOS-immunoreactive neurons and nerve fibers significantly declined with age. mRNA and protein expression of c-kit and nNOS decreased with aging. The functional study showed that the spontaneous contractility was decreased in aged rat, whereas EFS responses in the presence of atropine and L-NG-Nitroarginine methyl ester were increased in aged rat. In conclusion, the decrease of proportion of proper smooth muscle, the density of ICC and nNOS-immunoreactive neuronal fibers, and the number of nNOS-immunoreactive neurons during the aging process may explain the aging-associated colonic dysmotility.

Tumor Stem Cells (CD271, c-kit, SOX10) in Melanomas

Melanoma cells that express stem cell marker CD271 are shown to form tumors when transplanted into nude or immunodeficient mice. These tumors have a higher metastatic potential and worse prognosis than melanomas resulting from transplantation of CD271-negative cells. We studied stem cell markers (CD271, c-kit, SOX1O) in melanomas, correlating their presence with prognostic factors and outcome. A total of 82 melanomas in tissue microarrays were immunostained for CD271, c-kit, and SOX10. Results were correlated with clinicopathologic prognostic parameters (Breslow depth of invasion, Clark level, sentinel lymph node status, and pathologic stage) and outcome (recurrence, metastases, and death). Of the 82 melanomas, CD271 was expressed in 18 (21%), c-kit in 47 (57%), and SOX10 in all (100%). CD271 does show correlation with metastases (P=0.05). c-kit is associated with favorable prognostic parameters [Breslow depth (P<0.001) and pathologic stage (P=0.02)] and with improved outcome [recurrence (P=0.03) and metastases (P=0.004)]. Although SOX10 is a good diagnostic marker, it cannot be used for prognosis because it is expressed in all the melanomas studied. In conclusion, CD271 expression in melanomas is associated with increased frequency of metastases, and c-kit immunoreactivity is associated with favorable prognostic parameters and improved outcome.

Evaluation of c-kit protein (CD117) expression in common salivary gland neoplasms.

Background:Adenoid cystic carcinoma (AdCC) is a malignant salivary gland neoplasm with poor long-term prognosis. Differentiating between AdCC and other salivary gland neoplasms can be a diagnostic challenge, particularly in examining tissues obtained from small incisional biopsies.Aim:The aim of this study was to evaluate c-kit expression in four common benign and malignant salivary gland neoplasms.Materials and Methods:Immunohistochemical techniques were used to analyze the level of c-kit expression in normal salivary gland (n = 10) and four different types of salivary gland tumors: Pleomorphic adenoma (PA) (n = 17), AdCC (n = 9), polymorphous low-grade adenocarcinoma (PLGA) (n = 4) and mucoepidermoid carcinoma (MEC) (n = 6). Samples were immunostained using monoclonal antibody against c-kit.Results:The immunoreactivity for c-kit was found in all cases of AdCC, PLGA and MEC and majority of PAs. Positive reactivity was observed in more than 50% of the tumor cells of AdCC and less than 50% in PLGA. PA did not show strong immunostaining and c-kit was predominantly localized to the cell membrane. Furthermore, the difference in the expression of c-kit between the benign and malignant neoplasms was not statistically significant.Conclusions:CD117 expression itself cannot be used as a marker in differential diagnosis of salivary gland neoplasms. However, the percentage of the CD117 immunoreactive cells and the staining intensities appeared to be important factors in distinguishing AdCC from PLGA and PA.

Notch Signaling–related Therapeutic Strategies With Novel Drugs in Neuroblastoma Spheroids

Neuroblastoma is a severe pediatric tumor characterized by poor prognosis. Identification of novel molecular targets and diversion of investigations on new drug trials is mandatory for cancer therapy. In this study, vinorelbine tartrate, lithium chloride, clomipramine, and medroxyprogesterone acetate are used for the possible new treatment modalities in neuroblastoma cells. Notch and c-kit are novel molecules in cancer research, and Notch pathway is one of the emerging molecules in the neuroblastoma pathogenesis. Cytotoxic effects of these drugs at different time points, with different doses were studied in the SH-SY5Y human neuroblastoma cell line. Analysis of Notch and c-kit signaling with immunohistochemistry were constituted in multicellular tumor spheroids, and morphologic investigation was performed for digital imaging of cancer stem cells (CSCs) with electron microscopy. Size kinetics of spheroids was also determined after drug treatment. Results showed that all drugs were cytotoxic for neuroblastoma cells. Yet, this cytotoxic action did not correlate with the inhibitory effects in cell signaling. Neuroblastoma spheroids showed increased immunoreactivity of Notch signaling and c-kit. Altered ultrastructural CSCs morphology was observed after clomipramine and medroxyprogesterone acetate treatment compared with other drugs. Lithium chloride showed cellular membrane destruction for both CSCs and the remaining population. In this study, independent effects of cytotoxicity in tumor cells with respect to CSCs were determined. Redundant cells, which are the bulk population in tumor a compound, destroyed with therapy, were neither a target for treatment nor a remarkable investigation of cancer.

The Justy mutant mouse strain produces a spontaneous murine model of salivary gland cancer with myoepithelial and basal cell differentiation

We previously identified a novel mutant mouse strain on the C3HeB/FeJ background named Justy. This strain bears a recessive mutation in the Gon4l gene that greatly reduces expression of the encoded protein, a nuclear factor implicated in transcriptional regulation. Here, we report that Justy mutant mice aged 6 months or older spontaneously developed carcinomas with myoepithelial and basaloid differentiation in salivary glands with an incidence of ∼25%. Tumors developed proximate to submandibular glands and to a lesser extent in the sublingual and parotid glands. Histologically, tumors often had central cavitary lesions filled with necrotic debris that were lined by tumor cells, and had spindle and epithelioid cell differentiation with lesser basaloid to clear cell features. Tumor tissue often had variable evidence of a high mitotic rate, pleomorphism, and invasion into adjacent salivary glands. Neoplastic cells had diffuse immunoreactivity for pancytokeratin (AE1/AE3) and p63. Although CK5/6 immunostaining was seen in the much of the tumor cells, it was often lacking in pleomorphic areas. Tumor cells lacked immunoreactivity for alpha-smooth muscle actin, S100, c-Kit, and glial fibrillary acid protein. In addition, tumors had immunoreactivity for phosphorylated and total epidermal growth factor receptor, suggesting that EGFR signaling may participate in growth regulation of these tumors. These findings indicate that the salivary gland carcinomas occur spontaneously in Justy mice, and that these tumors may offer a valuable model for study of EGFR regulation. In combination, our data suggest that Justy mice warrant further investigation for use as a mouse model for human salivary gland neoplasia.

Phasic Contractions in Urinary Bladder from Juvenile versus Adult Pigs

AimsAlterations in properties of the bladder with maturation are relevant physiologically and pathophysiologically. The aim of this study was to investigate alterations in bladder properties with maturation in juvenile vs. adult pig, focussing on differences between layers of the bladder wall (mucosa vs. detrusor) and the presence and functional contribution of interstitial cells (ICs).MethodsBasal and cholinergic-induced phasic contractions (PCs) in mucosal and denuded-detrusor strips from juvenile and adult pigs were assessed. Expression of c-kit, a marker of ICs, was investigated in the mucosa and the detrusor layers of the pig bladder. The functional role of ICs in mediating PCs was examined using imatinib.ResultsMucosal strips from juvenile and adult pig bladders demonstrated basal PCs whilst denuded-detrusor strips did not. PCs of mucosal strips from juvenile pigs were significantly greater than those from adult bladders. Immunoreactivity for c-kit was detected in mucosa and detrusor layers of pig bladder. Histological studies demonstrated a distinct layer of smooth muscle between the urothelium and bladder detrusor, termed the muscularis mucosa. Imatinib was only effective in inhibiting PCs in mucosal strips from juvenile pigs. Imatinib inhibited the carbachol-induced PCs of both juvenile and adult denuded-detrusor strips, although strips from juvenile bladders demonstrated a trend towards being more sensitive to this inhibition.ConclusionsWe confirm the presence of c-kit positive ICs in pig urinary bladder. The enhanced PCs of mucosal strips from juvenile animals could be due to altered properties of ICs or the muscularis mucosa in the bladders of these animals.

Functions and Imaging of Mast Cell and Neural Axis of the Gut

Close association between nerves and mast cells in the gut wall provides the microanatomic basis for functional interactions between these elements, supporting the hypothesis that a mast cell-nerve axis influences gut functions in health and disease. Advanced morphology and imaging techniques are now available to assess structural and functional relationships of the mast cell-nerve axis in human gut tissues. Morphologic techniques including co-labeling of mast cells and nerves serve to evaluate changes in their densities and anatomic proximity. Calcium (Ca(++)) and potentiometric dye imaging provide novel insights into functions such as mast cell-nerve signaling in the human gut tissues. Such imaging promises to reveal new ionic or molecular targets to normalize nerve sensitization induced by mast cell hyperactivity or mast cell sensitization by neurogenic inflammatory pathways. These targets include proteinase-activated receptor (PAR) 1 or histamine receptors. In patients, optical imaging in the gut in vivo has the potential to identify neural structures and inflammation in vivo. The latter has some risks and potential of sampling error with a single biopsy. Techniques that image nerve fibers in the retina without the need for contrast agents (optical coherence tomography and full-field optical coherence microscopy) may be applied to study submucous neural plexus. Moreover, the combination of submucosal dissection, use of a fluorescent marker, and endoscopic confocal microscopy provides detailed imaging of myenteric neurons and smooth muscle cells in the muscularis propria. Studies of motility and functional gastrointestinal disorders would be feasible without the need for full-thickness biopsy.

Role of Ki-67 as a prognostic factor in gastrointestinal stromal tumors

To investigate primarily the prognostic value of Ki-67, as well as other parameters, in gastrointestinal stromal tumors (GISTs). Ki-67, c-KIT, platelet-derived growth factor receptor-alpha (PDGFRα), smooth muscle actin (SMA), CD34, S100 were stained for immunohistochemistry which was performed on formalin-fixed, paraffin-embeded sections on representative block from each case. Proliferation index counted by Ki-67 antibody was calculated as a number of positive nuclear reaction over 100 cells. Immunoreactivity for c-KIT and PDGFRα was evaluated semiquantitatively (weak, intermediate, strong) and for c-KIT type of reactivity was analyzed (cytoplasmic, membrane and "dot-like" staining). Immunoreactivity for SMA, CD34 and S100 were was evaluated as positive or negative antigen expression. Pathologic parameters investigated in this study included tumor size, cell type (pure spindle, pured epitheloid mixed spindle and epitheloid), mitotic count, hemorrhage, necrosis, mucosal ulceration. Clinical data included age, gender, primary tumor location and spread of disease. χ² test and Student's t-test were used for comparisons of baseline characteristics. The Cox's proportional hazard model was used for univariable and multivariable analyses. Survival rates were calculated by Kaplan-Meier method and statistical significance was determined by the log-rank test. According to the stage of disease, there were 36 patients with localized disease, 29 patients with initially localized disease but with its recurrence in the period of follow up, and finally, 35 patients had metastatic disease from the very beginning of disease. Tumor originated most commonly in the stomach (41%), small intestine was the second most common location (36%). The mean size of primary tumors was 6.5 cm. The mean duration of follow-up was 60 mo. Multiple parameters were analyzed for their effect on overall survival, but no one reached statistical significance (P = 0.06). Analysis of time to progression/relapse in initially localized disease (univariate analysis), tumor size, mitotic count, Ki-67 and type of d-KIT distribution (cytoplasmic vs membrane/"dot-like") showed statistically significant correlation. In multivariate analysis in the group of patients with localized disease, there were only 2 parameters that have impact on relapse, Ki-67 and SMA (P < 0.0001 and P < 0.034, respectively). Furthermore, Ki-67 was analyzed in localized disease vs localized with recurrence and metastatic disease. It was shown that there is a strict difference between these 2 groups of patients (median value was 2.5 for localized disease vs 10.0 for recurrent/metastatic disease, P < 0.0001). It was also shown that the cut-off value which is still statistically significant in terms of relapse on the level of 6%. The curves for survival on that cut-off level are significantly different (P < 0.04, Cox F). Ki-67 presents a significant prognostic factor for GIST recurrence which could be of great importance in evaluating malignant potential of disease.