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Background: Massive oropharyngeal bleeding post-chemoradiotherapy is a life-threatening condition that requires emergent management., Methods: This retrospective case series included 11 patients with oropharyngeal squamous cell carcinoma who suffered from massive bleeding during or following treatment with definitive chemoradiotherapy. Details of acute and definitive management of oropharyngeal bleeding are reported., Results: Nine of 11 hemorrhagic events occurred a mean (SD) of 88.6 days (53.6) after radiotherapy. Airway intubation and embolization were performed in 10 of 11 patients, followed by surgery in 7 of 11 patients. The most commonly embolized vessels were the external carotid and lingual arteries. At the time of discharge, 3 of 11 patients had a tracheostomy, and 7 of 11 continued to use a gastrostomy tube. Four patients died., Conclusions: Hemorrhagic complications in oropharyngeal cancer treatment require emergent responses. Developing a workflow for coordination between multidisciplinary teams can maximize probability of survival and decrease morbidity., (© 2024 Wiley Periodicals LLC.)

Importance: Transoral robot-assisted surgery (TORS) continues to have a major role in the treatment of oropharyngeal cancer. As new iterations of robotic technology are increasingly utilized, it is important to share learning experiences and clinical outcomes data, to optimize technical efficiency and clinical care., Observations: This was a retrospective review of a large academic institution's initial clinical use of the da Vinci Single Port (SP) compared with the da Vinci Si (Si) system. A total of 205 TORS cases were reviewed: 109 in the SP group (November 22, 2018, through September 30, 2020), and 96 in the Si group (January 1, 2016, through November 12, 2018). Both groups had comparable operative times, rates of postoperative pharyngeal hemorrhage, length of hospital stay, and duration of nasogastric feeding tube use. There was no difference in pathological characteristics, rates of positive margins, or indications for or time to initiation of adjuvant therapy between the groups. The collective experience of 6 faculty members-who have trained 139 TORS surgeons for the SP system rollout-was compiled to provide a summary of learning experiences and technical notes on safe and efficient operation of the SP system., Conclusions and Relevance: This Review found that the functional and oncologic outcomes were comparable between TORS cases performed with the Si and SP systems, and they had similar complication rates. Recognized advantages of the SP over the Si system include the availability of bipolar-energized instruments, a usable third surgical arm, and improved camera image quality.

Purpose: Neoadjuvant targeted therapy provides a brief, preoperative window of opportunity that can be exploited to individualize cancer care based on treatment response. We investigated whether response to neoadjuvant therapy during the preoperative window confers survival benefit in patients with operable head and neck squamous cell carcinoma (HNSCC)., Patients and Methods: A pooled analysis of treatment-naïve patients with operable HNSCC enrolled in one of three clinical trials from 2009 to 2020 (NCT00779389, NCT01218048, NCT02473731). Neoadjuvant regimens consisted of EGFR inhibitors (n = 83) or anti-ErbB3 antibody therapy (n = 9) within 28 days of surgery. Clinical to pathologic stage migration was compared with disease-free survival (DFS) and overall survival (OS) while adjusting for confounding factors using multivariable Cox regression. Circulating tumor markers validated in other solid tumor models were analyzed., Results: 92 of 118 patients were analyzed; all patients underwent surgery following neoadjuvant therapy. Clinical to pathologic downstaging was more frequent in patients undergoing neoadjuvant targeted therapy compared with control cohort (P = 0.048). Patients with pathologic downstage migration had the highest OS [89.5%; 95% confidence interval (CI), 75.7-100] compared with those with no stage change (58%; 95% CI, 46.2-69.8) or upstage (40%; 95% CI, 9.6-70.4; P = 0.003). Downstage migration remained a positive prognostic factor for OS (HR, 0.22; 95% CI, 0.05-0.90) while adjusting for measured confounders. Downstage migration correlated with decreased circulating tumor markers, SOX17 and TAC1 (P = 0.0078)., Conclusions: Brief neoadjuvant therapy achieved pathologic downstaging in a subset of patients and was associated with significantly better DFS and OS as well as decreased circulating methylated SOX17 and TAC1., (©2023 American Association for Cancer Research.)

Background: Transoral robotic surgery has been successfully used by head and neck surgeons for a variety of procedures but is limited by rigid instrumentation and line-of-sight visualization. Non-linear systems specifically designed for the aerodigestive tract are needed. Ease of use of these new systems in both training and clinical environments is critical in its widespread adoption., Methods: Residents, fellows, and junior faculty performed four tasks on an anatomical airway mannequin using the Medrobotics FLEX™ Robotic System: expose and incise the tonsil, grasp the epiglottis, palpate the vocal processes, and grasp the interarytenoid space. These tasks were performed once a day for four days; after a 4-month time gap, subjects were asked to perform these same tasks for three more days. Time to task completion and total distance driven were tracked. In addition, a retrospective analysis was performed analyzing one attending physician's experience with clinical usage of the robot., Results: 13 subjects completed the initial round of the mannequin simulation and 8 subjects completed the additional testing 4 months later. Subjects rapidly improved their speed and efficiency at task completion. Junior residents were slower in most tasks initially compared to senior trainees but quickly reached similar levels of efficiency. Following the break there was minimal degradation in skills and continued improvement in efficiency was observed with additional trials. There was significant heterogeneity in the analyzed clinical cases, but when analyzing cases of similar complexity and pathology, clear decreases in overall operative times were demonstrable., Conclusion: Novice users quickly gained proficiency with the FLEX™ Robotic System in a training environment, and these skills are retained after several months. This learning could translate to the clinical setting if a proper training regimen is developed. The Medrobotics FLEX™ Robotic System shows promise as a surgical tool in head and neck surgery in this study., (© 2021. The Author(s).)

Introduction: Head and Neck Cancer Awareness and Screening Programs (HNCASP) are popular community outreach events hosted by academic and community otolaryngology departments. However, long-term follow-up of participants is lacking., Patients and Methods: Participants of a HNCASP held at an academic cancer center prospectively filled out demographic and risk factor surveys followed by HNC screening examination. A phone interview was conducted for participants between 2012 and 2016 with suspicious findings to assess outcomes., Results: Participants were largely Caucasian, female, and had health insurance, reflecting the setting at an academic medical center. Despite this, there were 156 (16.8%) positive screenings; 47 of these completed follow up interviews. Twelve (1.1% of all participants) cancer cases were confirmed., Discussion: A significant proportion of HNCASP participants benefited from this screening opportunity. Education regarding HNC is the primary benefit and motivational factor for attendance of HNCASPs, although a significant subset of patients was identified that needed follow-up, and several cancers were detected.

Background: Functional interactions between immune cells and neoplastic cells in the tumor immune microenvironment have been actively pursued for both biomarker discovery for patient stratification, as well as therapeutic anti-cancer targets to improve clinical outcomes. Although accumulating evidence indicates that intratumoral infiltration of immune cells has prognostic significance, limited information is available on the spatial infiltration patterns of immune cells within intratumoral regions. This study aimed to understand the intratumoral heterogeneity and spatial distribution of immune cell infiltrates associated with cell phenotypes and prognosis in head and neck squamous cell carcinoma (HNSCC)., Methods: A total of 88 specimens of oropharyngeal squamous cell carcinoma, categorized into discovery (n = 38) and validation cohorts (n = 51), were analyzed for immune contexture by multiplexed immunohistochemistry (IHC) and image cytometry-based quantification. Tissue segmentation was performed according to a mathematical morphological approach using neoplastic cell IHC images to dissect intratumoral regions into tumor cell nests versus intratumoral stroma., Results: Tissue segmentation revealed heterogeneity in intratumoral T cells, varying from tumor cell nest-polarized to intratumoral stroma-polarized distributions. Leukocyte composition analysis revealed higher ratios of T H 1/T H 2 in tumor cell nests with higher percentages of helper T cells, B cells, and CD66b + granulocytes within intratumoral stroma. A discovery and validation approach revealed a high density of programmed death receptor-1 (PD-1) + helper T cells in tumor cell nests as a negative prognostic factor for short overall survival. CD163 + tumor-associated macrophages (TAM) provided the strongest correlation with PD-1 + helper T cells, and cases with a high density of PD-1 + helper T cells and CD163 + TAM had a significantly shorter overall survival than other cases., Conclusion: This study reveals the significance of analyzing intratumoral cell nests and reports that an immune microenvironment with a high density of PD-1 + helper T cells in tumoral cell nests is a poor prognostic factor for HNSCC., Competing Interests: TT is a paid consultant for Ono Pharmaceutical and receives speaker fees from Merck Sharp & Dohme Corp, Ono Pharmaceutical, and Bristol-Myers Squibb. HO is an employee of SCREEN Holdings Co., Ltd. SSh is an employee of SCREEN Holdings Co., Ltd. EK is a paid consultant for Roche Diagnostics and receives speaker fees from Chugai Pharmaceutical. KI received research funding from the SCREEN Holdings Co., Ltd. LC is a paid consultant for Cell Signaling Technologies, AbbVie Inc., and Shasqi Inc., received reagent and/or research support from Plexxikon Inc., Pharmacyclics, Inc., Acerta Pharma, LLC, Deciphera Pharmaceuticals, LLC, Genentech, Inc., Roche Glycart AG, Syndax Pharmaceuticals Inc., Innate Pharma, NanoString Technologies, and Cell Signaling Technologies, is a member of the Scientific Advisory Boards of Syndax Pharmaceuticals, Carisma Therapeutics, Zymeworks, Inc, Verseau Therapeutics, Cytomix Therapeutics, Inc., Hibercell, Inc., Alkermes, Inc., Genenta Sciences, and Kineta Inc, and is a member of the Lustgarten Therapeutics Advisory working group, and the AstraZeneca Partner of Choice Network. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Yoshimura, Tsujikawa, Mitsuda, Ogi, Saburi, Ohmura, Arai, Shibata, Thibault, Chang, Clayburgh, Yasukawa, Miyagawa-Hayashino, Konishi, Itoh, Coussens and Hirano.)

Metastatic progression defines the final stages of tumor evolution and underlies the majority of cancer-related deaths. The heterogeneity in disseminated tumor cell populations capable of seeding and growing in distant organ sites contributes to the development of treatment resistant disease. We recently reported the identification of a novel tumor-derived cell population, circulating hybrid cells (CHCs), harboring attributes from both macrophages and neoplastic cells, including functional characteristics important to metastatic spread. These disseminated hybrids outnumber conventionally defined circulating tumor cells (CTCs) in cancer patients. It is unknown if CHCs represent a generalized cancer mechanism for cell dissemination, or if this population is relevant to the metastatic cascade. Herein, we detect CHCs in the peripheral blood of patients with cancer in myriad disease sites encompassing epithelial and non-epithelial malignancies. Further, we demonstrate that in vivo-derived hybrid cells harbor tumor-initiating capacity in murine cancer models and that CHCs from human breast cancer patients express stem cell antigens, features consistent with the potential to seed and grow at metastatic sites. Finally, we reveal heterogeneity of CHC phenotypes reflect key tumor features, including oncogenic mutations and functional protein expression. Importantly, this novel population of disseminated neoplastic cells opens a new area in cancer biology and renewed opportunity for battling metastatic disease.

Background: Levels of circulating hybrid cells (CHCs), a newly identified circulating tumor cell (CTC), correlate with disease stage and progression in cancer. We investigated their utility to risk-stratify patients with clinically N0 (cN0) oral cavity squamous cell carcinoma (OCSCC), and to identify patients with occult cervical lymph node metastases (pN+)., Methods: We analyzed peripheral blood samples for CHCs with co-expression of cytokeratin (tumor) and CD45 (leukocyte) from 22 patients with cN0 OCSCC using immunofluorescence microscopy, then correlated levels with pathologic lymph node status., Results: CHC levels exceeded CTCs and correlated with the presence of both clinically overt (p = 0.002) and occult nodal metastases (p = 0.006)., Conclusions: For evaluated cN0 OCSCC patients, those with cN0 → pN+ status harbored elevated CHC levels compared to patients without occult disease. Our findings highlight a promising blood-based biologic assay with potential utility to determine the necessity of surgical neck dissection for staging and treatment., (© 2021 Wiley Periodicals LLC.)

Background: Sinonasal squamous cell carcinoma (SNSCC) is a rare malignancy that poses management challenges. Although surgery and chemoradiation therapy (CRT) remain therapeutic mainstays, induction chemotherapy (IC) has emerged as a useful adjunct with locally advanced disease. This study used the National Cancer Data Base (NCDB) to examine treatment outcomes for patients diagnosed with SNSCC., Methods: The NCDB (2004-2015) was queried for cases with SNSCC. Multivariate hazard regression modeling was used to identify significant predictors of 24-month and 60-month overall survival (OS) including treatment modality., Results: A total of 3516 patients with SNSCC met inclusion criteria, including 1750 patients (49.8%) treated with surgery ± adjuvant therapy, 1352 (38.5%) treated with definitive radiotherapy (RT) or CRT, 300 (8.5%) who underwent IC followed by definitive CRT, and 114 (3.2%) who received IC followed by surgery and adjuvant therapy. Hazard modeling for confirmed treatment modality significantly associated (p < 0.001) with OS after adjustment. Patients who received surgical intervention ± adjuvant therapy had lower 24-month and 60-month mortality risk compared to definitive RT or CRT (hazard ratio [HR] ≥ 1.97; p < 0.001) or IC followed by definitive CRT (HR ≥ 1.73; p < 0.001). Compared to primary surgery ± adjuvant therapy, patients undergoing IC then surgery had similar 24-month and 60-month OS (p ≥ 0.672) after adjustment., Conclusion: Multimodality therapy, including surgical intervention, associates with improved OS after multifactorial adjustments. IC followed by surgery associated with improved OS compared to IC, followed by CRT and CRT alone. Study results highlight the utility of surgery toward optimizing OS in patients with SNSCC and demonstrates the potential utility of IC when primary surgical management is not preferred., (© 2020 ARS-AAOA, LLC.)

Biomarker assessments of tumor specimens is widely used in cancer research to audit tumor cell intrinsic as well as tumor cell extrinsic features including the diversity of immune, stromal, and mesenchymal cells. To comprehensively and quantitatively audit the tumor-immune microenvironment (TiME), we developed a novel multiplex immunohistochemistry (mIHC) platform and computational image processing workflow using a single formalin-fixed paraffin-embedded (FFPE) tissue section. Herein, we validated this platform using nine matched primary newly diagnosed and recurrent head and neck squamous cell carcinoma (HNSCC) sections sequentially subjected to immunodetection with a panel of 29 antibodies identifying malignant tumor cells, and 17 distinct leukocyte lineages and their functional states. Image cytometric analysis was applied to interpret chromogenic signals from digitally scanned and coregistered light microscopy-based images enabling identification and quantification of individual tumor cells, structural features, immune cell phenotypes and their functional state. In agreement with our previous study via a 12-plex imaging mIHC platform, myeloid-inflamed status in newly diagnosed primary tumors associated with significantly short progression free survival, independent of lymphoid-inflamed status. Spatial distribution of tumor and immune cell lineages in TiME was also examined and revealed statistically significant CD8 + T cell exclusion from tumor nests, whereas regulatory T cells and myeloid cells, when present in close proximity to tumor cells, highly associated with rapid cancer recurrence. These findings indicate presence of differential immune-spatial profiles in newly diagnosed and recurrent HNSCC, and establish the robustness of the 29-plex mIHC platform and associated analytics for quantitative analysis of single tissue sections revealing longitudinal TiME changes., (© 2020 Elsevier Inc. All rights reserved.)

Background: Solid organ transplant recipients are known to be at an increased risk of cancer development, but research on head and neck cancer in transplant recipients has been limited and prior risk assessments may not be accurate., Methods: A retrospective review using a national Veterans Administration database to query outpatient problem lists for ICD codes indicating solid organ transplant and subsequent diagnosis of head and neck cancer., Results: In a study of 30 939 656 patients (37 969 solid organ transplants and 113 995 head and neck cancers), history of transplant significantly predicted head and neck cancer, with relative risks ranging from 1.85 (thyroid) to 2.91 (salivary gland). Worse overall survival (OS) was seen for head and neck cancer patients with prior transplants., Conclusions: In a large case-control study, prior transplant was a risk factor for head and neck cancer development and worse OS for head and neck cancer patients., (© 2019 Wiley Periodicals, Inc.)

Background: Papillary thyroid carcinoma (PTC) follows an indolent course; however, up to 30% of patients develop recurrent disease requiring further treatment. Profiling PTC immune complexity may provide new biomarkers for improved risk prediction., Methods: Immune complexity profiles were quantitatively evaluated by multiplex immunohistochemistry (mIHC) in archived tissue sections from 39 patients with PTC, and were assessed for correlations with aggressive histopathological features based on the presence of lymphovascular invasion and/or extrathyroidal extension, and BRAF V600E mutational status., Results: mIHC revealed two distinct immune clusters stratifying patients: a lymphoid-inflamed group (higher CD8 + T cells, reduced dendritic and mast cells) and a myeloid/hypo-inflamed group that correlated with aggressive pathological features. BRAF mutation was not associated with aggressive pathological features but did correlate with increased mast cell density., Conclusions: Distinct immune microenvironments exist in PTC correlating with pathological aggressiveness. Immune-based biomarkers associated with possible tumor-immune interactions may be used for risk stratification., (© 2019 Wiley Periodicals, Inc.)

Image cytometry enables quantitative cell characterization with preserved tissue architecture; thus, it has been highlighted in the advancement of multiplex immunohistochemistry (IHC) and digital image analysis in the context of immune-based biomarker monitoring associated with cancer immunotherapy. However, one of the challenges in the current image cytometry methodology is a technical limitation in the segmentation of nuclei and cellular components particularly in heterogeneously stained cancer tissue images. To improve the detection and specificity of single-cell segmentation in hematoxylin-stained images (which can be utilized for recently reported 12-biomarker chromogenic sequential multiplex IHC), we adapted a segmentation algorithm previously developed for hematoxlin and eosin-stained images, where morphological features are extracted based on Gabor-filtering, followed by stacking of image pixels into n-dimensional feature space and unsupervised clustering of individual pixels. Our proposed method showed improved sensitivity and specificity in comparison with standard segmentation methods. Replacing previously proposed methods with our method in multiplex IHC/image cytometry analysis, we observed higher detection of cell lineages including relatively rare T H 17 cells, further enabling sub-population analysis into T H 1-like and T H 2-like phenotypes based on T-bet and GATA3 expression. Interestingly, predominance of T H 2-like T H 17 cells was associated with human papilloma virus (HPV)-negative status of oropharyngeal squamous cell carcinoma of head and neck, known as a poor-prognostic subtype in comparison with HPV-positive status. Furthermore, T H 2-like T H 17 cells in HPV-negative head and neck cancer tissues were spatiotemporally correlated with CD66b + granulocytes, presumably associated with an immunosuppressive microenvironment. Our cell segmentation method for multiplex IHC/image cytometry potentially contributes to in-depth immune profiling and spatial association, leading to further tissue-based biomarker exploration. © 2019 International Society for Advancement of Cytometry., (© 2019 International Society for Advancement of Cytometry.)

Here, we describe a multiplexed immunohistochemical platform with computational image processing workflows, including image cytometry, enabling simultaneous evaluation of 12 biomarkers in one formalin-fixed paraffin-embedded tissue section. To validate this platform, we used tissue microarrays containing 38 archival head and neck squamous cell carcinomas and revealed differential immune profiles based on lymphoid and myeloid cell densities, correlating with human papilloma virus status and prognosis. Based on these results, we investigated 24 pancreatic ductal adenocarcinomas from patients who received neoadjuvant GVAX vaccination and revealed that response to therapy correlated with degree of mono-myelocytic cell density and percentages of CD8 + T cells expressing T cell exhaustion markers. These data highlight the utility of in situ immune monitoring for patient stratification and provide digital image processing pipelines to the community for examining immune complexity in precious tissue sections, where phenotype and tissue architecture are preserved to improve biomarker discovery and assessment., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Venous thromboembolism (VTE) is a major cause of perioperative morbidity and mortality. Historically, otolaryngology surgery has been seen as very low risk of VTE, given the relatively short procedures and healthy patient population. However, head and neck surgery patients have multiple additional risk factors for VTE compared to general otolaryngology patients, and only recently has research been directed at examining this population of patients regarding VTE risk., Review: VTE has long been recognized as a major issue in other surgical specialties, with VTE rates of 15-60 % in some specialties in the absence of prophylaxis with either mechanical compression or anticoagulation. Multiple large-scale retrospective studies have shown that the incidence of VTE in otolaryngology patients is quite low, ranging between 0.1 and 1.6 %. However, these studies indicated that head and neck cancer patients may have an increased risk of VTE. Further retrospective studies focusing on head and neck cancer patients found a VTE rate of approximately 2 %, but one study also found a suspected VTE rate of 5.6 % based on clinical symptoms, indicating that retrospective studies may underreport the true incidence. A single prospective study found a 13 % risk of VTE after major head and neck surgery. Furthermore, risk stratification using the Caprini risk assessment model demonstrates that the highest risk patients may have a VTE risk of 18.3 %, although this may be lowered (but not eliminated) through the use of appropriate prophylactic anticoagulation., Conclusion: VTE is likely a more significant concern in head and neck surgery patients than previously realized. Appropriate prophylaxis with mechanical compression and anticoagulation is essential; risk stratification may serve as a useful tool to identify head and neck cancer patients at highest risk for VTE., Competing Interests: The authors declare that they have no competing interests.

Objective: This study describes the potential application of intraoperative ultrasound imaging during transoral robotic surgery (TORS)., Methods: Ultrasound imaging was performed during transoral robotic resection of oropharyngeal tumors in 10 patients at a tertiary academic center. Ultrasound imaging was utilized to identify large-caliber vessels adjacent to the surgical site. Measurements were also taken on the ultrasound of tumor thickness to determine the deep margin. Following resection, the tumor was sectioned, and a gross measurement of the tumor thickness was obtained., Results: Intraoperative ultrasound use led to the identification of larger-caliber blood vessels within the operative field prior to encountering them visually. Ultrasound could also aid in defining deep tumor margins; the tumor thickness measured via ultrasound was found to be accurate within 1 to 2 mm of the grossly measured tumor thickness. This allowed for focused, careful dissection to protect and avoid blood vessels during dissection as well as improved tumor resection., Conclusions: The use of intraoperative ultrasound provides additional information to the head and neck surgeon during TORS. This may be used to identify blood vessels and assess tumor margins, thereby improving the safety and efficacy of TORS., (© The Author(s) 2015.)

Coccidioidomycosis (valley fever) is caused by the dimorphic fungi Coccidioides immitis or Coccidioides posadasii. Most infections are asymptomatic or result in self-limited pneumonia; extrapulmonary dissemination via either hematogenous or lymphatic spread is rare. Here, we present a case of cervical C. immitis lymphadenitis that resulted in fistula formation to the esophagus via mediastinal extension. This case highlights a very unusual extrapulmonary manifestation of coccidioidomycosis, the difficulty in diagnosing coccidioidal infection when it is not suspected, and the importance of obtaining a thorough exposure history to assist with diagnosis.

The objective of this study is to establish normative waveform data for the external branch of the superior laryngeal nerve (SLN) utilizing laryngeal surface electrodes and intraoperative neurophysiological monitoring (IONM) in conjunction with a clinical neurophysiologist. A retrospective chart review of 91 consecutive at-risk SLN were identified in 51 patients in whom IONM using laryngeal surface electrodes was performed by a clinical neurophysiologist using Dragonfly (Neurovision Medical Products, Ventura, CA) recording electrodes and a Protektor (Natus Medical Inc., San Carlos, CA)16 channel- intraoperative nerve monitoring system. Inclusion criteria were met for 30 SLN. Data collected included preoperative diagnosis, surgical procedure, rates of nerve identification and stimulation, and waveform characteristics. Waveform analysis for 30 SLN yielded a peak latency of 4.0 ± 0.2 ms, onset latency 2.3 ± 0.1 ms, peak-to-peak amplitude of 220.4 ± 31.1 µV, onset-to-peak amplitude of 186.0 ± 25.0 µV, and stimulation current threshold of 0.55 ± 0.03 mA (data = mean ± SEM). Two patients had abnormal SLN function documented clinically on postoperative laryngoscopic examination. Laryngeal surface electrodes were successfully utilized to identify and monitor SLN function intraoperatively. IONM using laryngeal surface electrodes enables analysis of waveform morphology and latency in addition to threshold and amplitude data obtained with the traditional NIM system, potentially improving the performance of nerve monitoring during thyroid surgery., (© 2014 Wiley Periodicals, Inc.)

Importance: Venous thromboembolism (VTE) is associated with significant morbidity and mortality in surgery patients, but little data exist on the incidence of VTE in head and neck cancer surgical patients., Objective: To determine the incidence of VTE in postoperative patients with head and neck cancer., Design, Setting, and Participants: A prospective study of 100 consecutive patients hospitalized at a tertiary care academic surgical center who underwent surgery to treat head and neck cancer. Routine chemoprophylaxis was not used. On postoperative day (POD) 2 or 3, participants received clinical examination and duplex ultrasonographic evaluation (US). Participants with negative findings on clinical examination and US were followed up clinically; participants with evidence of deep venous thrombosis (DVT) or pulmonary embolism (PE) were given therapeutic anticoagulation. Participants with superficial VTE underwent repeated US on POD 4, 5, or 6. Participants were monitored for 30 days after surgery., Main Outcome and Measure: Total number of new cases of VTE (superficial and deep) identified within 30 days of surgery and confirmed on diagnostic imaging., Results: Of the 111 participants enrolled, 11 withdrew before completing the study; thus, 100 participants were included. The overall incidence of VTE was 13%. Eight participants were identified with clinically significant VTE: 7 DVT and 1 PE. An additional 5 participants had asymptomatic lower extremity superficial VTE detected on US alone. Fourteen percent of patients received some form of postoperative anticoagulation therapy; the rate of bleeding complications in these patients (30.1%) was higher than that in patients without anticoagulation therapy (5.6%) (P = .01)., Conclusions and Relevance: Hospitalized patients with head and neck cancer not routinely receiving anticoagulation therapy after surgery have an increased risk of VTE. Bleeding complications are elevated in patients receiving postoperative anticoagulation.

Background: Supracricoid partial laryngectomy (SCPL) is an option for laryngeal cancer resection that preserves laryngeal function; however, little information exists regarding factors that are associated with functional outcomes., Methods: A medical chart review was performed on patients that underwent SCPL at our institution between 2006 and 2011. Data were collected on surgical, voice, and swallowing outcomes., Results: Eighteen patients were identified. Thirteen underwent cricohyoidoepiglottopexy (CHEP) and 5 had a cricohyoidopexy (CHP). Mean follow-up was 737 days. On average, decannulation occurred at 27.4 days and feeding tube removal at 87.9 days postoperatively. Sixty-seven percent of patients tolerated an unrestricted diet at follow-up. Increased age and a CHP procedure were associated with negative outcomes. Age may be a proxy for more extensive disease and prior treatments., Conclusion: Patients who undergo an SCPL require extensive rehabilitation after surgery. Those who have undergone multiple cancer interventions and have more extensive surgery may be at risk for poorer outcomes., (Copyright © 2013 Wiley Periodicals, Inc.)

This article reviews the evidence behind surgical innovations and effect on treatment-related morbidity to examine how they may be integrated into modern management strategies for oral cavity and oropharyngeal squamous cell carcinoma (SCC). Technologic advances, including transoral laser microsurgery and transoral robotic surgery, along with the application of sentinel lymph node biopsy for oral cavity and oropharyngeal SCC are discussed., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Combined inhibition of epidermal growth factor receptor (EGFR) and insulin-like growth factor-1 receptor (IGF-1R) has been proposed as a therapy for cutaneous squamous cell carcinoma of the head and neck (SCCHN)., Methods: Receptor expression and downstream signaling were assessed in cutaneous squamous cell carcinoma (SCC) cell lines and patient samples. EGFR and IGF-1R signaling was inhibited in cutaneous SCC cell lines using erlotinib and/or picropodophyllin., Results: EGFR and IGF-1R were overexpressed in cutaneous SCCHN specimens relative to normal skin. Dual inhibition of both receptors prevented cell growth and decreased activation of Akt and p42/44 mitogen-activated protein kinase (MAPK) more effectively than either inhibitor alone., Conclusion: Dual inhibition of EGFR and IGF-1R is effective at blocking cell growth, and is correlated with inhibition of Akt and p42/44 MAPK, suggesting that this may be a promising treatment for cutaneous SCCHN., (Copyright © 2012 Wiley Periodicals, Inc.)

Objective: To compare and contrast the manifestations and surgical management of subglottic stenosis in patients with airway obstruction attributed to granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, and those with idiopathic subglottic stenosis (iSGS)., Design: Retrospective medical chart review. Review of subglottic stenosis cases seen in the otolaryngology department of an academic medical center from 2005 through 2010. Data were obtained on disease presentation, operative management. and findings., Setting: Tertiary referral center., Participants: A total of 24 patients with iSGS and 15 patients with GPA-associated subglottic stenosis (GPA-SGS)., Results: All individuals with iSGS were female, and 40% of patients with GPA-SGS were male (P < .01). Patients with iSGS tended to have a higher Myer-Cotton stenosis grade at the time of dilation than those with GPA-SGS (P = .02). Individuals with GPA-SGS were more likely to undergo tracheotomy as a result of disease-related complications than individuals with iSGS (P < .01). No patients with an open airway reconstruction in the iSGS group required follow-up mechanical dilation. In contrast, all patients with open airway reconstructions in the GPA-SGS group underwent more than 1 subsequent airway dilation (P < .01)., Conclusions: While surgical utilization is the mainstay of treatment in iSGS and GPA-SGS, iSGS occurs almost exclusively in females and presents with a greater degree of stenosis at the time of endoscopic dilation. In contrast, GPA-SGS is associated with greater rates of tracheotomy. Open airway reconstruction may be used in the treatment of iSGS and GPA-SGS but is much more effective in iSGS.

Objectives/hypothesis: To describe the otolaryngologic presentation and natural history of granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, and to compare otolaryngologic outcomes of patients with systemic GPA to those with a limited form of GPA confined to the head and neck., Study Design: Retrospective chart review., Methods: Review of GPA cases (identified by serology, biopsy, or clinical presentation) seen in the otolaryngology department of an academic medical center., Results: A total of 24 patients were identified; each patient was followed for an average 6.8 years. Sinusitis and subglottic stenosis were the most commonly observed head and neck manifestations at diagnosis, seen in 64% and 36%, respectively. Over time, disease spread to additional sites in more than half the cohort (n = 14), but only two of 13 patients with disease initially limited to the head and neck developed pulmonary disease, and none developed renal disease. Cumulatively, otitis media was more likely to be observed in patients with systemic disease (P = .04). Patients with localized (n = 12) and systemic (n = 12) GPA did not have significantly different rates of surgical interventions (0.55 vs. 0.72 surgical interventions/patient-year of follow-up, respectively, P = .19)., Conclusions: GPA has a variety of head and neck manifestations, most commonly sinusitis, nasal disease, subglottic stenosis, and otitis media. GPA commonly progresses to involve additional sites, regardless of the extent of disease. These patients require frequent surgical intervention, and the clinician should remain vigilant for progression of disease., (Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.)

Objectives/hypothesis: Open airway reconstruction is considered definitive treatment of laryngotracheal stenosis (LTS). Although most cases of LTS are not autoimmune, there are few data reported in patients with Wegener's granulomatosis. In this study, we aimed to assess outcomes of airway reconstruction in LTS patients with Wegener's compared to nonautoimmune patients., Study Design: Retrospective chart review of LTS cases managed with open airway reconstruction at an academic medical center., Methods: Patients who underwent open airway reconstruction for LTS due to Wegener's or nonautoimmune causes were identified from 1995 to 2010. Clinical, demographic, and procedural data were recorded. Fisher exact test, Mann-Whitney U test, and McNemar's test were used to test for significance., Results: A total of 53 patients were identified; eight Wegener's, 45 nonautoimmune, with median follow-up time of 8.3 and 1.8 years, respectively. Before reconstruction, there was no statistical difference between Wegener's and nonautoimmune patients with previous dilations (88% vs. 68%, P = .41) and tracheostomy dependence (50% vs. 42%, P = .72). Following reconstruction, 75% Wegener's and 36% nonautoimmune patients required further dilations (P = .05), with a decannulation rate of 75% and 58% (P = 1.0), respectively., Conclusions: Wegener's patients have an increased need for dilations after open airway reconstruction for LTS. However, these patients can be decannulated after surgery at a rate similar to patients with nonautoimmune LTS., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Accumulating evidence suggests that self-renewal and differentiation capabilities reside only in a subpopulation of tumor cells, termed cancer stem cells (CSCs), whereas the remaining tumor cell population lacks the ability to initiate tumor development or support continued tumor growth. In head and neck squamous cell carcinoma (HNSCC), as with other malignancies, cancer stem cells have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In this paper we summarize the current knowledge of the role of CSCs in HNSCC and discuss the therapeutic implications and future directions of this field.

In inflammatory bowel disease (IBD), aberrant activation of innate and adaptive immune responses enhances mucosal permeability through mechanisms not completely understood. To examine the role of epithelial nuclear factor (NF-kappaB) in IBD-induced enhanced permeability, epithelial-specific IkappaBalpha mutant (NF-kappaB super repressor) transgenic (TG) mice were generated. NF-kB activation was inhibited in TG mice, relative to wild-type mice, following T cell-mediated immune cell activation using an anti-CD3 monoclonal antibody. Furthermore, epithelial NF-kappaB super repressor protein inhibited diarrhea and blocked changes in transepithelial resistance and transmucosal flux of alexa350 (0.35 kDa) and dextran3000 (3 kDa). In vivo perfusion loop studies in TG mice revealed reversed net water secretion and reduced lumenal flux of different molecular probes (bovine serum albumin, alexa350, and dextran3000). Cell-imaging and immunoblotting of low-density, detergent-insoluble membrane fractions confirmed that tight junction proteins (occludin, claudin-1 and zona occludens-1) are internalized through an NF-kappaB-dependent pathway. Taken together, these data suggest that IBD-associated diarrhea results from NF-kappaB-mediated tight junction protein internalization and increased paracellular permeability. Thus, reduction of epithelial NF-kappaB activation in IBD may repair defects in epithelial barrier function, reduce diarrhea, and limit protein (eg, serum albumin) losses. Epithelial NF-kappaB activation induced by mucosal T cells, therefore, actively plays a role in opening paracellular spaces to promote transmucosal fluid effux into the intestinal lumen.

Background & Aims: Inflammatory bowel disease (IBD) is a multifactorial disease thought to be caused by alterations in epithelial function, innate and adaptive immunity, and luminal microbiota. The specific role of epithelial barrier function remains undefined, although increased activity of intestinal epithelial myosin light chain kinase (MLCK), which is the primary mechanism of tumor necrosis factor-induced barrier dysfunction, occurs in human IBD. Our aim was to determine whether, in an intact epithelium, primary dysregulation of the intestinal epithelial barrier by pathophysiologically relevant mechanisms can contribute to development of colitis., Methods: We developed transgenic (Tg) mice that express constitutively active MLCK (CA-MLCK) specifically within intestinal epithelia. Their physiology, immune status, and susceptibility to disease were assessed and compared with non-Tg littermate controls., Results: CA-MLCK Tg mice demonstrated significant barrier loss but grew and gained weight normally and did not develop spontaneous disease. CA-MLCK Tg mice did, however, develop mucosal immune activation demonstrated by increased numbers of lamina propria CD4(+)lymphocytes, redistribution of CD11c+cells, increased production of interferon-gamma and tumor necrosis factor, as well as increased expression of epithelial major histocompatibility complex class I. When challenged with CD4+CD45+Rb(hi) lymphocytes, Tg mice developed an accelerated and more severe form of colitis and had shorter survival times than non-Tg littermates., Conclusions: Primary pathophysiologically relevant intestinal epithelial barrier dysfunction is insufficient to cause experimental intestinal disease but can broadly activate mucosal immune responses and accelerate the onset and severity of immune-mediated colitis.

Background & Aims: LIGHT (lymphotoxin-like inducible protein that competes with glycoprotein D for herpes virus entry on T cells) is a tumor necrosis factor core family member that regulates T-cell activation and causes experimental inflammatory bowel disease. Additional data suggest that LIGHT may be involved in the pathogenesis of human inflammatory bowel disease. The aim of this study was to determine if LIGHT is capable of signaling directly to intestinal epithelia and to define the mechanisms and consequences of such signaling., Methods: The effects of LIGHT and interferon-gamma on barrier function, cytoskeletal regulation, and tight junction structure were assessed in mice and intestinal epithelial monolayers., Results: LIGHT induced barrier loss in cultured epithelia via myosin II regulatory light chain (MLC) phosphorylation; both barrier loss and MLC phosphorylation were reversed by MLC kinase (MLCK) inhibition. Pretreatment with interferon-gamma, which induced lymphotoxin beta receptor (LT beta R) expression, was required for these effects, and neither barrier dysfunction nor intestinal epithelial MLC phosphorylation occurred in LT beta R knockout mice. In cultured monolayers, endocytosis of the tight junction protein occludin correlated with barrier loss. Internalized occludin colocalized with caveolin-1. LIGHT-induced occludin endocytosis and barrier loss were both prevented by inhibition of caveolar endocytosis., Conclusions: T cell-derived LIGHT activates intestinal epithelial LT beta R to disrupt barrier function. This requires MLCK activation and caveolar endocytosis. These data suggest a novel role for LIGHT in disease pathogenesis and suggest that inhibition of MLCK-dependent caveolar endocytosis may represent an approach to restoring barrier function in inflammatory bowel disease.

Enteropathogenic E. coli (EPEC) is a major cause of infantile diarrhea, but the pathophysiology underlying associated diarrhea is poorly understood. We examined the role of the luminal membrane Cl(-)/OH(-) exchange process in EPEC pathogenesis using in vitro and in vivo models. Cl(-)/OH(-) exchange activity was measured as OH(-) gradient-driven (36)Cl(-) uptake. EPEC infection (60 minutes-3 hours) inhibited apical Cl(-)/OH(-) exchange activity in human intestinal Caco-2 and T84 cells. This effect was dependent upon the bacterial type III secretory system (TTSS) and involved secreted effector molecules EspG and EspG2, known to disrupt the host microtubular network. The microtubule-disrupting agent colchicine (100 muM, 3 hours) also inhibited (36)Cl(-) uptake. The plasma membrane expression of major apical anion exchanger DRA (SLC26A3) was considerably reduced in EPEC-infected cells, corresponding with decreased Cl(-)/OH(-) exchange activity. Confocal microscopic studies showed that EPEC infection caused a marked redistribution of DRA from the apical membrane to intracellular compartments. Interestingly, infection of cells with an EPEC mutant deficient in espG significantly attenuated the decrease in surface expression of DRA protein as compared with treatment with wild-type EPEC. EPEC infection in vivo (1 day) also caused marked redistribution of surface DRA protein in the mouse colon. Our data demonstrate that EspG and EspG2 play an important role in contributing to EPEC infection-associated inhibition of luminal membrane chloride transport via modulation of surface DRA expression.

Background & Aims: Tumor necrosis factor (TNF) plays a critical role in intestinal disease. In intestinal epithelia, TNF causes tight junction disruption and epithelial barrier loss by up-regulating myosin light chain kinase (MLCK) activity and expression. The aim of this study was to determine the signaling pathways by which TNF causes intestinal epithelial barrier loss., Methods: Caco-2 cells that were either nontransfected or stably transfected with human TNF receptor 1 (TNFR1) or TNFR2 and mouse colonocytes were used for physiologic, morphologic, and biochemical analyses., Results: Colitis induced in vivo by adoptive transfer of CD4(+)CD45RB(hi) T cells was associated with increased epithelial MLCK expression and myosin II regulatory light chain (MLC) phosphorylation as well as morphologic tight junction disruption. In vitro studies showed that TNF caused similar increases in MLCK expression and MLC phosphorylation, as well as barrier dysfunction, in Caco-2 monolayers only after interferon (IFN)-gamma pretreatment. This reductionist model was therefore used to determine the molecular mechanism by which IFN-gamma and TNF synergize to cause intestinal epithelial barrier loss. IFN-gamma priming increased TNFR1 and TNFR2 expression, and blocking antibody studies showed that TNFR2, but not TNFR1, was required for TNF-induced barrier dysfunction. Transgenic TNFR2, but not TNFR1, expression allowed IFN-gamma-independent TNF responses., Conclusions: IFN-gamma primes intestinal epithelia to respond to TNF by inducing TNFR2 expression, which in turn mediates TNF-induced MLCK-dependent barrier dysfunction. The data further suggest that epithelial TNFR2 blockade may be a novel approach to restore barrier function in intestinal disease.

Acute T cell-mediated diarrhea is associated with increased mucosal expression of proinflammatory cytokines, including the TNF superfamily members TNF and LIGHT. While we have previously shown that epithelial barrier dysfunction induced by myosin light chain kinase (MLCK) is required for the development of diarrhea, MLCK inhibition does not completely restore water absorption. In contrast, although TNF-neutralizing antibodies completely restore water absorption after systemic T cell activation, barrier function is only partially corrected. This suggests that, while barrier dysfunction is critical, other processes must be involved in T cell-mediated diarrhea. To define these processes in vivo, we asked whether individual cytokines might regulate different events in T cell-mediated diarrhea. Both TNF and LIGHT caused MLCK-dependent barrier dysfunction. However, while TNF caused diarrhea, LIGHT enhanced intestinal water absorption. Moreover, TNF, but not LIGHT, inhibited Na+ absorption due to TNF-induced internalization of the brush border Na+/H+ exchanger NHE3. LIGHT did not cause NHE3 internalization. PKCalpha activation by TNF was responsible for NHE3 internalization, and pharmacological or genetic PKCalpha inhibition prevented NHE3 internalization, Na+ malabsorption, and diarrhea despite continued barrier dysfunction. These data demonstrate the necessity of coordinated Na+ malabsorption and barrier dysfunction in TNF-induced diarrhea and provide insight into mechanisms of intestinal water transport.

Myosin light chain kinase (MLCK) is expressed as long and short isoforms from unique transcriptional start sites within a single gene. Tumor necrosis factor (TNF) augments intestinal epithelial long MLCK expression, which is critical to cytoskeletal regulation. We found that TNF increases long MLCK mRNA transcription, both in human enterocytes in vitro and murine enterocytes in vivo.5'-RACE identified two novel exons, 1A and 1B, which encode alternative long MLCK transcriptional start sites. Chromatin immunoprecipitation (ChIP) and site-directed mutagenesis identified two essential Sp1 sites upstream of the exon 1A long MLCK transcriptional start site. Analysis of deletion and truncation mutants showed that a 102-bp region including these Sp1 sites was necessary for basal transcription. A promoter construct including 4-kb upstream of exon 1A was responsive to TNF, AP-1, or NFkappaB, but all except NFkappaB responses were absent in a shorter 2-kb construct, and all responses were absent in a 1-kb construct. Electrophoretic mobility shift assays, ChIP, and site-directed mutagenesis explained these data by identifying three functional AP-1 sites between 2- and 4-kb upstream of exon 1A and two NFkappaB sites between 1- and 2-kb upstream of exon 1A. Analysis of differentiating epithelia showed that only well differentiated enterocytes activated the 4-kb long MLCK promoter in response to TNF, and consensus promoter reporters demonstrated that TNF-induced NFkappaB activation decreased during differentiation while TNF-induced AP-1 activation increased. Thus either AP-1 or NFkappaB can up-regulate long MLCK transcription, but the mechanisms by which TNF up-regulates intestinal epithelial long MLCK transcription from exon 1A are differentiation-dependent.

The intestinal epithelial barrier is frequently disrupted in inflammatory bowel disease (IBD) and this has been proposed to play a role in disease pathogenesis and reactivation. In vitro studies show that cytokine-induced epithelial barrier dysfunction can be mediated by increased myosin light chain kinase (MLCK) expression and subsequent myosin II regulatory light chain (MLC) phosphorylation. However, this has never been examined in human disease. The aim of these studies, therefore, was to determine whether MLCK is upregulated in the intestinal epithelium of IBD patients. MLCK expression and MLC phosphorylation in human intestinal resection and biopsy specimens were determined by quantitative immunofluorescence microscopy and correlated with clinical and histopathological data. The data show that ileal epithelial MLCK expression was mildly upregulated in inactive IBD. Expression increased further in active disease, with progressive increases in MLCK expression correlating positively with histological disease activity. This correlation between activity and MLCK expression was also seen in individual patients where areas of differing disease activity were analyzed. Colonic epithelial MLCK expression was similarly increased in active IBD and these increases also correlated positively with disease activity, both in individual patients and the overall study group. To evaluate MLCK enzymatic activity, MLC phosphorylation was assessed in snap-frozen colon biopsies. MLC phosphorylation was significantly increased in biopsies with active, but not inactive, IBD. Therefore, these data show that MLCK expression and enzymatic activity are increased in IBD. Moreover, the correlation with disease activity suggests that MLCK upregulation may contribute to barrier dysfunction and IBD pathogenesis.

Enteropathogenic Escherichia coli (EPEC) infection disrupts tight junctions (TJs) and perturbs intestinal barrier function in vitro. E. coli secreted protein F (EspF) is, in large part, responsible for these physiological and morphological alterations. We recently reported that the C57BL/6J mouse is a valid in vivo model of EPEC infection as EPEC colonizes the intestinal epithelium and effaces microvilli. Our current aim was to examine the effects of EPEC on TJ structure and barrier function of the mouse intestine and to determine the role of EspF in vivo. C57BL/6J mice were gavaged with approximately 2 x 10(8) EPEC organisms or PBS. At 1 or 5 days postinfection, mice were killed and ileal and colonic tissue was mounted in Ussing chambers to determine barrier function (measured as transepithelial resistance) and short circuit current. TJ structure was analyzed by immunofluorescence microscopy. Wild-type (WT) EPEC significantly diminished the barrier function of ileal and colonic mucosa at 1 and 5 days postinfection. Deficits in barrier function correlated with redistribution of occludin in both tissues. Infection with an EPEC strain deficient of EspF (delta espF) had no effect on barrier function at 1 day postinfection. Furthermore, delta espF had no effect on ileal TJ morphology and minor alterations of colonic TJ morphology at 1 day postinfection. In contrast, at 5 days postinfection, WT EPEC and delta espF had similar effects on barrier function and occludin localization. In both cases this was associated with immune activation, as demonstrated by increased mucosal tumor necrosis factor-alpha levels 5 days postinfection. In conclusion, these data demonstrate that WT EPEC infection of 6-8-week-old C57BL/6J mice (1) significantly decreases barrier function in the ileum and colon (2) redistributes occludin in the ileum and colon and (3) is dependent upon EspF to induce TJ barrier defects at early, but not late, times postinfection.

Disruption of the intestinal epithelial barrier occurs in many intestinal diseases, but neither the mechanisms nor the contribution of barrier dysfunction to disease pathogenesis have been defined. We utilized a murine model of T cell-mediated acute diarrhea to investigate the role of the epithelial barrier in diarrheal disease. We show that epithelial barrier dysfunction is required for the development of diarrhea. This diarrhea is characterized by reversal of net water flux, from absorption to secretion; increased leak of serum protein into the intestinal lumen; and altered tight junction structure. Phosphorylation of epithelial myosin II regulatory light chain (MLC), which has been correlated with tight junction regulation in vitro, increased abruptly after T cell activation and coincided with the development of diarrhea. Genetic knockout of long myosin light chain kinase (MLCK) or treatment of wild-type mice with a highly specific peptide MLCK inhibitor prevented epithelial MLC phosphorylation, tight junction disruption, protein leak, and diarrhea following T cell activation. These data show that epithelial MLCK is essential for intestinal barrier dysfunction and that this barrier dysfunction is critical to pathogenesis of diarrheal disease. The data also indicate that inhibition of epithelial MLCK may be an effective non-immunosuppressive therapy for treatment of immune-mediated intestinal disease.

Activation of Na(+)-nutrient cotransport leads to increased tight junction permeability in intestinal absorptive (villus) enterocytes. This regulation requires myosin II regulatory light chain (MLC) phosphorylation mediated by MLC kinase (MLCK). We examined the spatiotemporal segregation of MLCK isoform function and expression along the crypt-villus axis and found that long MLCK, which is expressed as two alternatively spliced isoforms, accounts for 97 +/- 4% of MLC kinase activity in interphase intestinal epithelial cells. Expression of the MLCK1 isoform is limited to well differentiated enterocytes, both in vitro and in vivo, and this expression correlates closely with development of Na(+)-nutrient cotransport-dependent tight junction regulation. Consistent with this role, MLCK1 is localized to the perijunctional actomyosin ring. Furthermore, specific knockdown of MLCK1 using siRNA reduced tight junction permeability in monolayers with active Na(+)-glucose cotransport, confirming a functional role for MLCK1. These results demonstrate unique physiologically relevant patterns of expression and subcellular localization for long MLCK isoforms and show that MLCK1 is the isoform responsible for tight junction regulation in absorptive enterocytes.

A critical function of the intestinal mucosa is to form a barrier that separates luminal contents from the interstitium. This intestinal barrier is compromised in a number of intestinal diseases, most notably inflammatory bowel disease. In vitro studies have demonstrated that cytokines elaborated by immune cells can cause the mucosal barrier to become leaky; these cytokines are known to be increased in intestinal mucosa involved in inflammatory bowel disease. Detailed information describing the mechanisms by which altered cytokine signaling occurs is not available, but recent data implicate the cytoskeleton within epithelial cells as a critical regulator of the mucosal barrier under physiological and pathophysiological conditions. Using available data, we describe a model of intestinal disease where an initial insult to the epithelial barrier may trigger a self-amplifying cycle of immune activation, cytokine release, and further barrier dysfunction. This model is supported by the observation that pharmacological abrogation of cytokine signaling corrects both barrier defects and clinical disease in animal models and human patients, although such therapy clearly has multiple mechanisms. Other therapeutic targets that represent strategies to prevent or reverse disease processes are also considered. The overarching hypothesis is that modulation of the mucosal epithelial barrier plays a critical role in the initiation and propogation of inflammatory intestinal diseases.