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author:("Zhang, duchen")
1.  Interval colorectal carcinoma: An unsolved debate 
World Journal of Gastroenterology  2015;21(45):12735-12741.
Colorectal carcinoma (CRC), as the third most common new cancer diagnosis, poses a significant health risk to the population. Interval CRCs are those that appear after a negative screening test or examination. The development of interval CRCs has been shown to be multifactorial: location of exam-academic institution versus community hospital, experience of the endoscopist, quality of the procedure, age of the patient, flat versus polypoid neoplasia, genetics, hereditary gastrointestinal neoplasia, and most significantly missed or incompletely excised lesions. The rate of interval CRCs has decreased in the last decade, which has been ascribed to an increased understanding of interval disease and technological advances in the screening of high risk individuals. In this article, we aim to review the literature with regard to the multifactorial nature of interval CRCs and provide the most recent developments regarding this important gastrointestinal entity.
PMCID: PMC4671029  PMID: 26668498
Colorectal carcinoma; Interval colorectal carcinoma; Post colonoscopy colorectal cancer; Detection; Screening
2.  Duodenal polyposis secondary to portal hypertensive duodenopathy 
Portal hypertensive duodenopathy (PHD) is a recognized, but uncommon finding of portal hypertension in cirrhotic patients. Lesions associated with PHD include erythema, erosions, ulcers, telangiectasia, exaggerated villous pattern and duodenal varices. However, duodenal polyposis as a manifestation of PHD is rare. We report a case of a 52-year-old man who underwent esophagogastroduodenoscopy and was found with multiple small duodenal polyps ranging in size from 1-8 mm. Biopsy of the representative polyps revealed polypoid fragments of duodenal mucosa with villiform hyperplasia lined by reactive duodenal/gastric foveolar epithelium and underlying lamina propria showed proliferating ectatic and congested capillaries. The features were diagnostic of polyps arising in the setting of PHD.
PMCID: PMC4658606  PMID: 26634042
Cirrhosis; Portal duodenopathy; Polyposis; Portal hypertension
3.  Pigment Epithelium-Derived Factor (PEDF) Inhibits Wnt/β-catenin Signaling in the Liver 
Pigment epithelium-derived factor (PEDF) is a secretory protein that inhibits multiple tumor types. PEDF inhibits the Wnt coreceptor, low-density lipoprotein receptor-related protein 6 (LRP6), in the eye, but whether the tumor-suppressive properties of PEDF occur in organs such as the liver is unknown.
Wnt-dependent regulation of PEDF was assessed in the absence and presence of the Wnt coreceptor LRP6. Whole genome expression analysis was performed on PEDF knockout (KO) and control livers (7 months). Interrogation of Wnt/β-catenin signaling was performed in whole livers and human hepatocellular carcinoma (HCC) cell lines after RNA interference of PEDF and restoration of a PEDF-derived peptide. Western diet feeding for 6 to 8 months was used to evaluate whether the absence of PEDF was permissive for HCC formation (n = 12/group).
PEDF levels increased in response to canonical Wnt3a in an LRP6-dependent manner but were suppressed by noncanonical Wnt5a protein in an LRP6-independent manner. Gene set enrichment analysis (GSEA) of PEDF KO livers revealed induction of pathways associated with experimental and human HCC and a transcriptional profile characterized by Wnt/β-catenin activation. Enhanced Wnt/β-catenin signaling occurred in KO livers, and PEDF delivery in vivo reduced LRP6 activation. In human HCC cells, RNA interference of PEDF led to increased levels of activated LRP6 and β-catenin, and a PEDF 34-mer peptide decreased LRP6 activation and β-catenin signaling, and reduced Wnt target genes. PEDF KO mice fed a Western diet developed sporadic well-differentiated HCC. Human HCC specimens demonstrated decreased PEDF staining compared with hepatocytes.
PEDF is an endogenous inhibitor of Wnt/β-catenin signaling in the liver.
PMCID: PMC4604042  PMID: 26473164
Extracellular Matrix; PEDF; Wnt/β-Catenin
4.  Triheptanoin for glucose transporter type I deficiency (G1D): Modulation of human ictogenesis, cerebral metabolic rate and cognitive indices by a food supplement 
JAMA neurology  2014;71(10):1255-1265.
G1D is commonly associated with electrographic spike-wave and - less-noticeably – with absence seizures. The G1D syndrome has long been attributed to energy (i.e., ATP-synthetic) failure, as have experimental, toxic-rodent epilepsies to impaired brain metabolism and tricarboxylic acid (TCA) cycle intermediate depletion. Indeed, a (seldom-acknowledged) function of glucose and other substrates is the generation of brain TCAs via carbon-donor reactions collectively named anaplerosis. However, TCAs are preserved in murine G1D. This renders inferences about energy failure premature and suggests a different hypothesis, also grounded on our findings, that consumption of alternate TCA precursors is stimulated, potentially detracting from other functions. Second, common ketogenic diets can ameliorate G1D seizures, but lead to a therapeutically-counterintuitive reduction in blood glucose available to the brain, and they can prove ineffective in 1/3 of cases. While developing G1D treatments, all of this motivated us to: a) uphold (rather than attenuate) the residual brain glucose flux that all G1D patients possess; and b) stimulate the TCA cycle, including anaplerosis. Therefore, we tested the medium-chain triglyceride triheptanoin, a widely-used medical food supplement that can fulfill both of these metabolic roles. The rationale is that ketone bodies derived from ketogenic diets are not anaplerotic, in contrast with triheptanoin metabolites, as we have shown in the G1D mouse brain.
We supplemented the regular diet of a case series of G1D patients with food-grade triheptanoin. First we confirmed that, despite their frequent electroencephalographic (EEG) presence as spike-waves, most seizures are rarely visible, such that perceptions by patients or others are inadequate for treatment evaluation. Thus, we used EEG, quantitative neuropsychological, blood analytical, and MRI cerebral metabolic rate measurements as main outcomes.
Academic and unsponsored.
Fourteen G1D children and adults not receiving a ketogenic diet.
Eleven patients tolerated triheptanoin without significant adverse effects. Spike-waves decreased robustly in all patients who manifested them. Additionally, neuropsychological performance and cerebral metabolic rate increased in most patients.
Triheptanoin can favorably influence cardinal aspects of neural function in G1D. Additionally, our outcome measures offer a framework for the evaluation of therapies for G1D and other encephalopathies associated with impaired intermediary metabolism.
PMCID: PMC4376124  PMID: 25110966
Glucose transporter; GLUT1; G1D; triheptanoin; C7 oil; metabolism; anaplerosis; MRI; EEG
5.  Impaired Autophagy Response in Human Hepatocellular Carcinoma 
Autophagy is a cellular lysosomal degradation mechanism has been implicated in chronic liver diseases and hepatocellular carcinoma (HCC). Association of autophagy defect with the development of human HCC has been shown in transgenic mouse model.
We performed this study to verify whether a defect in autophagy would play a role in human hepatocellular carcinoma (HCC).
Archival tissue sections of 20 patients with HCC with or without hepatitis C virus (HCV) infection were studied. All slides were immunostained using monoclonal antibodies to p62 and glypican-3 with appropriate positive and negative controls. The expression of p62 and glycican-3 in the HCC and the surrounding non-tumor were semiquantitated. The cytoplasmic staining was graded as negative, weak or strong.
Positive p62 staining was found in 20 out of 20 (100%) HCCs and negative staining was observed in 20 out of 20 non-tumor areas and cirrhotic nodules. Positive glypican-3 staining was found in 70% of HCCs and negative staining was seen in all non-tumor areas. An autophagy defect leading to increased expression of p62 and glypican-3 was also seen in the HCC cell line (Huh-7.5), but not in the primary human hepatocytes. Activation of cellular autophagy in Huh-7.5 cells efficiently cleared p62 and glypican-3 expression and inhibition of autophagy induced the expression of p62 and glypican-3.
This study shows that p62 is increased in HCC compared to the surrounding non-tumorous liver tissue suggesting that human HCCs are autophagy defective. We provide further evidence that glypican-3 expression in HCC may be also related to defective autophagy. Our study indicates that p62 immunostain may represent a novel marker for HCC.
PMCID: PMC4364514  PMID: 24369267
Hepatocellular Carcinoma; Autophagy; Glypican-3; p62; Immunostaining
6.  Proton pump inhibitor responsive esophageal eosinophilia, a distinct disease entity? 
World Journal of Gastroenterology : WJG  2014;20(30):10419-10424.
Recent studies have suggested the existence of a patient population with esophageal eosinophilia that responds to proton pump inhibitor therapy. These patients are being referred to as having proton pump inhibitor responsive esophageal eosinophilia (PPI-REE), which is currently classified as a distinct and separate disease entity from both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE). The therapeutic effect of proton pump inhibitor (PPI) on PPI-REE is thought to act directly at the level of the esophageal mucosa with an anti-inflammatory capacity, and completely independent of gastric acid suppression. The purpose of this manuscript is to review the mechanistic data of the proposed immune modulation/anti-inflammatory role of the PPI at the esophageal mucosa, and the existence of PPI-REE as a distinct disease entity from GERD and EoE.
PMCID: PMC4130848  PMID: 25132757
Gastroesophageal reflux disease; Eosinophilic esophagitis; Proton pump inhibitor responsive esophageal eosinophilia; Proton pump inhibitor
7.  A Protective Hsp70-TLR4 Pathway in Lethal Oxidant Lung Injury 
Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can exacerbate respiratory failure. Our previous study showed that toll-like receptor 4 (TLR4) confers protection against hyperoxia-induced lung injury and mortality. Hsp70 has potent cytoprotective properties and has been described as a TLR4 ligand in cell lines. We sought to elucidate the relationship between TLR4 and Hsp70 in hyperoxia-induced lung injury in vitro and in vivo and to define the signaling mechanisms involved. Wild type, TLR4−/− and Trif−/− (a TLR4 adapter protein) murine lung endothelial cells (MLEC) were exposed to hyperoxia. We found markedly elevated levels of intracellular and secreted Hsp70 from mice lung and MLEC after hyperoxia. We confirmed that Hsp70 and TLR4 co-immunoprecipitate in lung tissue and MLEC. Hsp70-mediated NFκB activation appears to depend upon TLR4. In the absence of TLR4, Hsp70 loses its protective effects in endothelial cells. Furthermore, these protective properties of Hsp70 are TLR4 adapter Trif-dependent, MyD88-independent. Hsp70-deficient mice have increased mortality during hyperoxia and lung-targeted adenoviral delivery of Hsp70 effectively rescues both Hsp70-deficient and wild type mice. Our studies are the first to define an Hsp70-TLR4-Trif cytoprotective axis in the lung and endothelial cells. This pathway is a potential therapeutic target against a range of oxidant-induced lung injuries.
PMCID: PMC3730854  PMID: 23817427
8.  Pathology of Alcoholic Liver Disease 
Alcohol-attributable burden on global health is increasing, and the relationship between population alcohol consumption and liver-related deaths is strong. Longstanding scientific and clinical work has led to a relatively thorough, if not complete, understanding of the effects of alcohol consumption on the liver. Pathologic features of alcoholic liver disease (ALD) are recognized by pathologists and used to assist clinicians in diagnosing and determining severity of disease in patients suspected of ALD. In this review, we discuss the pathologic manifestations of ALD and provide salient points on their pathophysiology. In addition, the benefits and indications of liver biopsy and important differential diagnoses, including features distinguishing these entities, are reviewed.
PMCID: PMC4521259  PMID: 26357621
Alcoholic liver disease; Steatosis; Steatohepatitis; Pathology
9.  Endothelial MKK3 is a critical mediator of lethal murine endotoxemia and acute lung injury 
Sepsis is a leading cause of intensive care unit admissions with high mortality and morbidity. Although outcomes have improved with better supportive care, specific therapies are limited. Endothelial activation and oxidant injury are key events in the pathogenesis of sepsis-induced lung injury. The signaling pathways leading to these events remain poorly defined and need to be studied. We sought to determine the role of MAP kinase kinase 3 (MKK3), a kinase of the p38 group in the pathogenesis of sepsis. We used a murine intraperitoneal lipopolysaccharide (LPS) model of systemic inflammation to mimic sepsis. Lung injury parameters were assessed in lung tissue and bronchoalveolar lavage. Primary lung endothelial cells were cultured and assessed for mediators of inflammation and injury such as ICAM-1, AP-1, NF-κB and mitochondrial ROS. Our studies demonstrate that MKK3 deficiency confers virtually complete protection against organ injury after intraperitoneal LPS. Specifically, MKK3 −/− mice were protected against acute lung injury, as assessed by reduced inflammation, mitochondrial reactive oxygen species (ROS) generation, endothelial injury and ICAM-1 expression after LPS. Our results show that endothelial MKK3 is required for inflammatory cell recruitment to the lungs, mitochondrial oxidant-mediated AP-1, NF-κB activation and ICAM-1 expression during LPS challenge. Collectively, these studies identify a novel role for MKK3 in lethal LPS responses and provide new therapeutic targets against sepsis and acute lung injury.
PMCID: PMC3552142  PMID: 23275604
10.  Era of universal testing of microsatellite instability in colorectal cancer 
Colorectal cancer (CRC) incidence and mortality are constantly decreasing, but CRC still remains the third most prevalent cancer and the third most common cause of cancer death in both males and females in the United States. Recent rapid declines in CRC incidence rates have largely been attributed to increases in screening that can detect and remove precancerous polyps, and the decrease in death rates for CRC largely reflects improvements in early detection, treatment and the understanding of molecular/genetic basis of CRC. One of the important molecular/genetic findings is the presence of microsatellite instability (MSI) in CRCs. Many studies have shown the importance of MSI testing in diagnosing Lynch syndrome and predicting prognosis and response to chemotherapeutic agents in CRCs. Increased emphasis has been placed on the importance of MSI testing for all newly diagnosed individuals with CRCs. Both immunohistochemical staining (IHC) and polymerase chain reaction (PCR)-based MSI testing show high sensitivity and specificity in detecting MSI. The current clinical guidelines and histopathology features are indicative of, but not reliable in diagnosing Lynch syndrome and CRCs with MSI. Currently, there are evidences that universal testing for MSI starting with either IHC or PCR-based MSI testing is cost effective, sensitive, specific and is getting widely accepted.
PMCID: PMC3613766  PMID: 23556052
Colorectal cancer; Lynch syndrome; Universal testing; DNA mismatch repair; Microsatellite instability
11.  Large ulcerated cecal lipoma mimicking malignancy 
Colonic lipomas are relatively uncommon tumors of mesenchymal origin, composed of well-differentiated adipose tissue supported by fibrous tissue, that usually occur in cecum and ascending colon. Colonic lipomas rarely cause symptoms and are usually detected incidentally. However, if the lesion is large, it may produce symptoms, such as abdominal pain, rectal bleeding, obstruction, intussusception, and even weight loss. Large colonic lipomas can be mistaken for malignancy, which may result in extensive surgical operations. We report a large broad-based ulcerated cecal lipoma in a 68-year-old woman, who presented with abdominal pain and weight loss. The ulcerated lesion was highly suspicious for malignancy radiologically and endoscopically. The patient underwent laparoscopic right-hemicolectomy, and the lesion was diagnosed as a cecal submucosal lipoma. The surgical approach remains the treatment of choice for large and complicated cases.
PMCID: PMC2999136  PMID: 21160661
Cecum; Lipoma; Carcinoma
12.  Toll-like receptor 4 deficiency causes pulmonary emphysema 
Journal of Clinical Investigation  2006;116(11):3050-3059.
TLRs have been studied extensively in the context of pathogen challenges, yet their role in the unchallenged lung is unknown. Given their direct interface with the external environment, TLRs in the lungs are prime candidates to respond to air constituents, namely particulates and oxygen. The mechanism whereby the lung maintains structural integrity in the face of constant ambient exposures is essential to our understanding of lung disease. Emphysema is characterized by gradual loss of lung elasticity and irreversible airspace enlargement, usually in the later decades of life and after years of insult, most commonly cigarette smoke. Here we show Tlr4–/– mice exhibited emphysema as they aged. Adoptive transfer experiments revealed that TLR4 expression in lung structural cells was required for maintaining normal lung architecture. TLR4 deficiency led to the upregulation of what we believe to be a novel NADPH oxidase (Nox), Nox3, in lungs and endothelial cells, resulting in increased oxidant generation and elastolytic activity. Treatment of Tlr4–/– mice or endothelial cells with chemical NADPH inhibitors or Nox3 siRNA reversed the observed phenotype. Our data identify a role for TLR4 in maintaining constitutive lung integrity by modulating oxidant generation and provide insights into the development of emphysema.
PMCID: PMC1616193  PMID: 17053835
13.  ERK1/2 mitogen-activated protein kinase selectively mediates IL-13–induced lung inflammation and remodeling in vivo 
Journal of Clinical Investigation  2005;116(1):163-173.
IL-13 dysregulation plays a critical role in the pathogenesis of a variety of inflammatory and remodeling diseases. In these settings, STAT6 is believed to be the canonical signaling molecule mediating the tissue effects of IL-13. Signaling cascades involving MAPKs have been linked to inflammation and remodeling. We hypothesized that MAPKs play critical roles in effector responses induced by IL-13 in the lung. We found that Tg IL-13 expression in the lung led to potent activation of ERK1/2 but not JNK1/2 or p38. ERK1/2 activation also occurred in mice with null mutations of STAT6. Systemic administration of the MAPK/ERK kinase 1 (MEK1) inhibitor PD98059 or use of Tg mice in which a dominant-negative MEK1 construct was expressed inhibited IL-13–induced inflammation and alveolar remodeling. There were associated decreases in IL-13–induced chemokines (MIP-1α/CCL-3, MIP-1β/CCL-4, MIP-2/CXCL-1, RANTES/CCL-5), MMP-2, -9, -12, and -14, and cathepsin B and increased levels of α1-antitrypsin. IL-13–induced tissue and molecular responses were noted that were equally and differentially dependent on ERK1/2 and STAT6 signaling. Thus, ERK1/2 is activated by IL-13 in the lung in a STAT6-independent manner where it contributes to IL-13–induced inflammation and remodeling and is required for optimal IL-13 stimulation of specific chemokines and proteases as well as the inhibition of specific antiproteases. ERK1/2 regulators may be useful in the treatment of IL-13–induced diseases and disorders.
PMCID: PMC1319220  PMID: 16374521

Results 1-13 (13)