Dietary cholesterol promotes steatohepatitis related hepatocellular carcinoma through dysregulated metabolism and calcium signaling.

The underlining mechanisms of dietary cholesterol and nonalcoholic steatohepatitis (NASH) in contributing to hepatocellular carcinoma (HCC) remain undefined. Here we demonstrated that high-fat-non-cholesterol-fed mice developed simple steatosis, whilst high-fat-high-cholesterol-fed mice developed NASH. Moreover, dietary cholesterol induced larger and more numerous NASH-HCCs than non-cholesterol-induced steatosis-HCCs in diethylnitrosamine-treated mice. NASH-HCCs displayed significantly more aberrant gene expression-enriched signaling pathways and more non-synonymous somatic mutations than steatosis-HCCs (335 ± 84/sample vs 43 ± 13/sample). Integrated genetic and expressional alterations in NASH-HCCs affected distinct genes pertinent to five pathways: calcium, insulin, cell adhesion, axon guidance and metabolism. Some of the novel aberrant gene expression, mutations and core oncogenic pathways identified in cholesterol-associated NASH-HCCs in mice were confirmed in human NASH-HCCs, which included metabolism-related genes (ALDH18A1, CAD, CHKA, POLD4, PSPH and SQLE) and recurrently mutated genes (RYR1, MTOR, SDK1, CACNA1H and RYR2). These findings add insights into the link of cholesterol to NASH and NASH-HCC and provide potential therapeutic targets.

Fecal Bacteria Act as Novel Biomarkers for Noninvasive Diagnosis of Colorectal Cancer.

Purpose: Gut microbiota have been implicated in the development of colorectal cancer. We evaluated the utility of fecal bacterial marker candidates identified by our metagenome sequencing analysis for colorectal cancer diagnosis.Experimental Design: Subjects (total 439; 203 colorectal cancer and 236 healthy subjects) from two independent Asian cohorts were included. Probe-based duplex quantitative PCR (qPCR) assays were established for the quantification of bacterial marker candidates.Results: Candidates identified by metagenome sequencing, including Fusobacterium nucleatum (Fn), Bacteroides clarus (Bc), Roseburia intestinalis (Ri), Clostridium hathewayi (Ch), and one undefined species (labeled as m7), were examined in fecal samples of 203 colorectal cancer patients and 236 healthy controls by duplex-qPCR. Strong positive correlations were demonstrated between the quantification of each candidate by our qPCR assays and metagenomics approach (r = 0.801-0.934, all P < 0.0001). Fn was significantly more abundant in colorectal cancer than controls (P < 0.0001), with AUROC of 0.868 (P < 0.0001). At the best cut-off value maximizing sum of sensitivity and specificity, Fn discriminated colorectal cancer from controls with a sensitivity of 77.7%, and specificity of 79.5% in cohort I. A simple linear combination of four bacteria (Fn + Ch + m7-Bc) showed an improved diagnostic ability compared with Fn alone (AUROC = 0.886, P < 0.0001) in cohort I. These findings were further confirmed in an independent cohort II. In particular, improved diagnostic performances of Fn alone (sensitivity 92.8%, specificity 79.8%) and four bacteria (sensitivity 92.8%, specificity 81.5%) were achieved in combination with fecal immunochemical testing for the detection of colorectal cancer.Conclusions: Stool-based colorectal cancer-associated bacteria can serve as novel noninvasive diagnostic biomarkers for colorectal cancer. Clin Cancer Res; 23(8); 2061-70. ©2016 AACR.

Antibiotic prescribing practices for catheter urine culture results.

BACKGROUND: The literature suggests that positive results of catheter urine cultures frequently lead to unnecessary antimicrobial prescribing, which therefore represents an important target for stewardship. OBJECTIVE: To assess the appropriateness of antibiotic prescribing in response to the results of urine cultures from patients with indwelling urinary catheters. METHODS: This retrospective study was conducted at a tertiary care centre and involved adults with indwelling urinary catheters from whom urine specimens were obtained for culture. Patients with positive or negative culture results were identified from microbiology laboratory reports. The medical records of consecutive patients were screened to select a sample of 80 inpatients (40 per group). Abstracted patient histories were independently evaluated by an expert panel of 3 infectious diseases consultants blinded to the decisions of prescribers and of fellow panelists. The primary end point was concordance of each patient's treatment decision (with respect to the indication) between the expert panel (based on majority agreement, i.e., at least 2 of the 3 expert panelists) and the prescriber. The secondary end points were unnecessary days of therapy and selected outcomes over a predefined period after urine was obtained for culture. RESULTS: A total of 591 charts were screened to generate the targeted number of patients. Baseline demographic characteristics were comparable for the 2 groups, except antibiotic exposure before urine collection was significantly more frequent for the group with negative culture results. The treatment decision was concordant in 40% (16/40) of the patients with a positive culture result and 85% (34/40) of those with a negative culture result (p < 0.001). The most common reason for discordance was administration of antibiotics when not indicated (23 of 24 patients with a positive result and 5 of 6 patients with a negative result), which accounted for 165 and 32 unnecessary days of therapy per 1000 inpatient-days, respectively (p < 0.001). Adverse effects occurred in 2 of the 23 patients with a positive result who received antibiotics that were not indicated. CONCLUSIONS: Appropriateness of antibiotic prescribing, as measured by concordance of decisions between the expert panel and prescribers, was more common among patients with negative urine culture results than among those with positive results. However, there is an opportunity to improve prescribing for both groups through antimicrobial stewardship initiatives. Unnecessary days of therapy and adverse effects were more common in patients with a positive culture result.

CONTEXTE: Selon la littérature, des résultats positifs à des cultures d'échantillons d'urine prélevés à partir d'une sonde vésicale entraînent souvent la prescription inutile d'antibiotiques; par conséquent, cette situation représente un objet important de gestion responsable des antimicrobiens. OBJECTIF: Évaluer la pertinence de la prescription d'antibiotiques sur la base de résultats des cultures d'échantillons d'urine prélevés chez les patients porteurs d'une sonde vésicale à demeure. MÉTHODES: La présente étude rétrospective a été menée dans un établissement de soins tertiaires auprès de patients adultes porteurs d'une sonde vésicale à demeure chez qui on a prélevé des échantillons d'urine à des fins de culture. Les patients avec des résultats de culture positifs ou négatifs ont été repérés à partir des rapports de microbiologie. Les dossiers médicaux d'une série consécutive de patients ont été examinés afin de choisir un échantillon de 80 patients hospitalisés (40 par groupe). Les historiques abrégés des patients ont été évalués indépendamment par un panel d'experts composé de trois consultants en maladies infectieuses qui ignoraient la décision des prescripteurs et les résultats des évaluations de leurs collègues panélistes. Le paramètre d'évaluation principal était la concordance de la décision thérapeutique (quant à l'indication) pour chaque patient entre le panel d'experts (selon un accord majoritaire, c.-à-d. au moins deux des trois panélistes experts) et le prescripteur. Les paramètres d'évaluation secondaires étaient le nombre de jours de traitement inutiles et certains résultats cliniques sur une période prédéterminée après l'obtention d'un échantillon d'urine à des fins de culture. RÉSULTATS: Un total de 591 dossiers de patients ont été analysés afin d'obtenir le nombre cible de patients pour l'étude. Les caractéristiques démographiques initiales étaient comparables dans les deux groupes, sauf l'exposition aux antibiotiques avant le prélèvement d'urine qui était significativement plus fréquente dans le groupe de patients ayant obtenu des résultats de culture négatifs. La décision thérapeutique concordait pour 40 % (16/40) des patients ayant obtenu des résultats positifs à la culture d'urine et pour 85 % (34/40) de ceux qui avaient obtenu des résultats négatifs (p < 0,001). La raison la plus fréquente expliquant la discordance entre les décisions thérapeutiques était l'administration non indiquée d'antibiotiques, une circonstance observée chez 23 patients sur 24 ayant obtenu des résultats positifs et 5 patients sur 6 ayant obtenu des résultats négatifs. Ces cas ont contribué respectivement à un total de 165 et de 32 jours de traitement inutiles par 1000 journées-patients hospitalisés (p < 0,001). Des effets indésirables sont survenus chez deux des 23 patients ayant obtenu un résultat positif et reçu des antibiotiques non indiqués. CONCLUSIONS: La pertinence de la prescription d'antibiotiques, telle qu'elle a été mesurée en fonction de la concordance des décisions entre le panel d'experts et les prescripteurs, était plus fréquente dans le cas des patients ayant obtenu des résultats négatifs à la culture d'urine que chez ceux dont ces résultats étaient positifs. Cependant, des mesures pour la gestion responsable des antimicrobiens pourraient améliorer la prescription dans les deux groupes. Le nombre de jours de traitement inutiles et les effets indésirables étaient plus fréquents chez les patients ayant obtenu des résultats positifs à la culture. [Traduction par l'éditeur].

The receptor TGR5 mediates the prokinetic actions of intestinal bile acids and is required for normal defecation in mice.

BACKGROUND & AIMS: Abnormal delivery of bile acids (BAs) to the colon as a result of disease or therapy causes constipation or diarrhea by unknown mechanisms. The G protein-coupled BA receptor TGR5 (or GPBAR1) is expressed by enteric neurons and endocrine cells, which regulate motility and secretion. METHODS: We analyzed gastrointestinal and colon transit, as well as defecation frequency and water content, in wild-type, knockout, and transgenic mice (trg5-wt, tgr5-ko, and tgr5-tg, respectively). We analyzed colon tissues for contractility, peristalsis, and transmitter release. RESULTS: Deoxycholic acid inhibited contractility of colonic longitudinal muscle from tgr5-wt but not tgr5-ko mice. Application of deoxycholic acid, lithocholic acid, or oleanolic acid (a selective agonist of TGR5) to the mucosa of tgr5-wt mice caused oral contraction and caudal relaxation, indicating peristalsis. BAs stimulated release of the peristaltic transmitters 5-hydroxytryptamine and calcitonin gene-related peptide; antagonists of these transmitters suppressed BA-induced peristalsis, consistent with localization of TGR5 to enterochromaffin cells and intrinsic primary afferent neurons. tgr5-ko mice did not undergo peristalsis or transmitter release in response to BAs. Mechanically induced peristalsis and transmitter release were not affected by deletion of tgr5. Whole-gut transit was 1.4-fold slower in tgr5-ko than tgr5-wt or tgr5-tg mice, whereas colonic transit was 2.2-fold faster in tgr5-tg mice. Defecation frequency was reduced 2.6-fold in tgr5-ko and increased 1.4-fold in tgr5-tg mice compared with tgr5-wt mice. Water content in stool was lower (37%) in tgr5-ko than tgr5-tg (58%) or tgr5-wt mice (62%). CONCLUSIONS: The receptor TGR5 mediates the effects of BAs on colonic motility, and deficiency of TGR5 causes constipation in mice. These findings might mediate the long-known laxative properties of BAs, and TGR5 might be a therapeutic target for digestive diseases.

Human tRNA genes function as chromatin insulators.

Insulators help separate active chromatin domains from silenced ones. In yeast, gene promoters act as insulators to block the spread of Sir and HP1 mediated silencing while in metazoans most insulators are multipartite autonomous entities. tDNAs are repetitive sequences dispersed throughout the human genome and we now show that some of these tDNAs can function as insulators in human cells. Using computational methods, we identified putative human tDNA insulators. Using silencer blocking, transgene protection and repressor blocking assays we show that some of these tDNA-containing fragments can function as barrier insulators in human cells. We find that these elements also have the ability to block enhancers from activating RNA pol II transcribed promoters. Characterization of a putative tDNA insulator in human cells reveals that the site possesses chromatin signatures similar to those observed at other better-characterized eukaryotic insulators. Enhanced 4C analysis demonstrates that the tDNA insulator makes long-range chromatin contacts with other tDNAs and ETC sites but not with intervening or flanking RNA pol II transcribed genes.

Laparoscopic treatment of liver tumours using a two-needle probe bipolar radiofrequency ablation device.

BACKGROUND: Many hepatobiliary centres are increasingly utilizing thermocoagulative devices such as bipolar-radiofrequency ablation (B-RFA). Compared with monopolar-radiofrequency ablation (M-RFA), B-RFA does not require grounding pads, thereby avoiding dermal burn injuries, and does not position probes directly into the tumour but rather on the perimeter. Additionally, B-RFA can precoagulate parenchyma to assist in hepatic resection. Herein, we report our early experience using B-RFA. METHODS: A retrospective review identified 68 patients who underwent M-RFA or B-RFA between June 2004 and September 2010 in an academic centre. Peri-operative metrics were analysed. RESULTS: M-RFA was used to treat 30 patients, whereas B-RFA was used for 17 patients. There were no differences in peri-operative metrics, survival or disease recurrence between M-RFA and B-RFA. Seventeen additional patients underwent B-RFA precoagulation during laparoscopic resection (segmentectomy in eleven patients and multi-segmental resection in six patients). Four patients with multifocal disease underwent procedures that combined B-RFA with resection. CONCLUSIONS: The early experience utilizing B-RFA demonstrates equivalency to M-RFA with respect to peri-operative metrics and survival. Moreover, B-RFA can be utilized to precoagulate tissue during a planned resection, making it not only a useful tool for tumour therapy but also a useful adjunct during surgical resections.

Enhanced composite electrospun nanofiber scaffolds for use in drug delivery.

The utility of nanofibrous electrospun composite scaffolds has greatly expanded over the last decade, so that they now serve as viable drug delivery vehicles for a host of different biomedical applications. The material properties of electrospun scaffolds are extremely advantageous for drug delivery, in which site-specificity and lower overall medicinal dosages lead to a potential industry-altering mechanism of delivering therapeutics. Different drugs used to predominantly treat infections and cancers can easily be incorporated and released at therapeutic dosages. Further, the inherent high porosity of these electrospun scaffolds allows for a more precisely controlled degradation which is tunable by polymer composition and fiber morphology, leading to sustained drug release. This review examines the current research and breakthrough discoveries that have elevated electrospun scaffolds to a cutting-edge technology that will dramatically alter the landscape of drug delivery.

Functionalization of poly(L-lactide) nanofibrous scaffolds with bioactive collagen molecules.

The utilization of electrospun biodegradable scaffolds by fine-tuning their biofunctionalities through a simple mixing method was demonstrated in this study. Poly(L-lactide) (PLLA)-based scaffolds containing small amounts of bioactive collagen type I molecules were investigated for enhancements in cellular behavior. Electron microscopy revealed no topological alterations of the fibers in the collagen/PLLA scaffolds when compared with pure PLLA scaffolds. Cell attachment after 24 h was robust on collagen/PLLA scaffolds, with cytoskeletal analysis showing that the attached cells were aligned along the fibers assuming a spindle-shape appearance. Despite these morphological differences, gene expression analyses revealed no apparent alterations in mRNA levels of four genes involved in cell attachment across the various scaffolds. Although cell proliferation was not adversely affected, there were clear differences in cell penetration; after 1 week, cells migrated through 32 and 85% of PLLA and collagen/PLLA scaffolds, respectively. Mineralization of primary calvaria osteoblasts provided further evidence that collagen-containing electrospun PLLA scaffolds could sustain cell differentiation. Overall, the inclusion of collagen type I in even miniscule amounts (<1 wt %) within electrospun PLLA scaffolds could effectively modulate certain aspects of cellular behavior.

Prevention of postsurgery-induced abdominal adhesions by electrospun bioabsorbable nanofibrous poly(lactide-co-glycolide)-based membranes.

OBJECTIVES: The objective of this study was to evaluate the efficacy of nonwoven bioabsorbable nanofibrous membranes of poly(lactideco-glycolide) for prevention of postsurgery-induced abdominal adhesions. SUMMARY BACKGROUND DATA: Recent reports indicated that current materials used for adhesion prevention have only limited success. Studies on other bioabsorbable materials using a new fabrication technique demonstrated the promising potential of generating an improved and inexpensive product that is suitable for a variety of surgical applications. METHODS: All rats underwent a midline celiotomy. The cecum was identified and scored using an abrasive pad until serosal bleeding was noted on the anterior surface. A 1 x 1 cm of abdominal wall muscle was excised directly over the cecal wound. The celiotomy was then closed in 2 layers immediately (control) after a barrier was laid in between the cecum and the abdominal wall. All rats underwent a second celiotomy after 28 days to evaluate the extent of abdominal adhesions qualitatively and quantitatively. RESULTS: Cecal adhesions were reduced from 78% in the control group to 50% in the group using biodegradable poly(lactide-co-glycolide) (PLGA) nonwoven nanofibrous membranes (n = 10, P = 0.2) and to 22% in the group using membranes containing PLGA and poly(ethylene glycol)/poly(D,L-lactide) (PEG-PLA) blends (n = 9, P = 0.03). Electrospinning method also enabled us to load an antibiotic drug Cefoxitin sodium (Mefoxin; Merck Inc., West Point, PA) with high efficacy. The electrospun PLGA/PEG-PLA membranes impregnated with 5 wt% cefoxitin sodium, which amounts to approximately 10% of the systemic daily dose typically taken after surgery in humans, completely prevented cecal adhesions (0%) in rats. CONCLUSIONS: Electrospun nonwoven bioabsorbable nanofibrous membranes of poly(lactide-co-glycolide) were effective to reduce adhesions at the site of injury using an objective rat model. The membrane acted as a physical barrier but with drug-delivery capability. The combined advantages of composition adjustment, drug-loading capability, and easy placement handling (relatively hydrophobic) make these membranes potentially successful candidates for further clinical evaluations.

Human lumbar facet joint capsule strains: I. During physiological motions.

BACKGROUND CONTEXT: The lumbar facet joint capsule is innervated with nociceptors and mechanoreceptors, and is thought to play a role in low back pain as well as to function proprioceptively. PURPOSE: In order to examine the facet capsule's potential proprioceptive role, relationships between intracapsular strain and relative spine position were examined. STUDY DESIGN/SETTING: Lumbar facet joint capsule strains were measured in human cadaveric specimens during displacement-controlled motions. METHODS: Ligamentous lumbar spine specimens (n=7) were potted and actuated without inducing a moment at the point of application. Spines were tested during physiological motions of extension, flexion, left and right lateral bending. Intervertebral angulations (IVA) were measured using biaxial inclinometers mounted on adjacent vertebrae. Joint moments were determined from the applied load at T12 and the respective moment arms. Capsule plane strains were measured by optically tracking the displacements of infrared reflective markers glued to capsule surfaces. Statistical differences (p<.05) in moment, IVA and strain were assessed across facet joint levels using analysis of variance and comparison of linear regressions. RESULTS: The developed moments and IVAs increased monotonically with increasing displacements; the relationships were highly correlated for all four motion types. Although highly variable among specimens, principal strains also increased monotonically in magnitude with increasing displacements during extension and flexion, but were more complex during lateral bending. At a given joint level, the absolute magnitudes of principal strains and IVA were largest during the same motion type. CONCLUSIONS: Distinct patterns in principal strains and IVA were identified during physiological motions, lending biomechanical support to the theory that lumbar facet joint capsules could function proprioceptively.

Human lumbar facet joint capsule strains: II. Alteration of strains subsequent to anterior interbody fixation.

BACKGROUND CONTEXT: In cases of low back pain associated with biomechanical lumbar instability, anterior interbody fixation can be used as a surgical treatment, but its affect on facet joint capsule strains is unknown. PURPOSE: To determine the effect of a single-level anterolateral interbody fixation, the changes in lumbar facet joint capsule strains at the level of and adjacent to the fixation were evaluated. STUDY DESIGN/SETTING: Human cadaveric lumbar spine specimens were tested under displacement control before and after the addition of a single anterior thoracolumbar plate (ATLP) on the L4-L5 motion body. METHODS: Ligamentous lumbar spine specimens (n=7) were potted and actuated before and after fixation of the L4-L5 motion segment with an ATLP in motions of extension, flexion, left and right bending. Joint moments were calculated from the applied load and respective moment arms. Intervertebral angulation was measured using biaxial inclinometers mounted onto adjacent vertebrae. Plane strains of the capsules were measured by optically tracking the displacements of small, infrared reflective markers glued to capsule surfaces. Statistical differences (p<.05) in moment, intervertebral angle and capsular strain were assessed using analysis of variance and comparison of linear regression lines. RESULTS: Fixation resulted in an increase in moment at the three vertebral levels for all motions. There was also an increase in intervertebral angle at L3-L4 and L5-S1, and a decrease in intervertebral angle at L4-L5 for all motions. Plane strains in the L3-L4 and L5-S1 facet capsules increased as a result of the fixation. L4-L5 facet capsules experienced decreased and increased strains ipsilateral and contralateral, respectively, to the instrumentation. CONCLUSION: Restriction of a vertebral motion segment using a single ATLP increased adjacent capsular strains, which if suprathreshold for capsule nociceptors, could play a role in low back pain.

Control of degradation rate and hydrophilicity in electrospun non-woven poly(D,L-lactide) nanofiber scaffolds for biomedical applications.

Typical properties of poly(D,L-lactide) (PLA)-based scaffolds (films and foams), such as long degradation time, mechanical stiffness and hydrophobicity, are sometimes not suitable for biomedical applications. These properties can be substantially altered by electrospinning of PLA blends with miscible poly(lactide-co-glycolide) (PLGA) random copolymers, poly(lactide-b-ethylene glycol-b-lactide) (PLA-b-PEG-b-PLA) triblock copolymers, and a lactide (used as a hydrolytic catalyst). Electrospun scaffolds based on the multi-component PLA blends, comprised of randomly interconnected webs of sub-micron sized fibers, have a bulk density of 0.3-0.4 g/cm3. In this study, the concentration effects of PLA-b-PEG-b-PLA triblock copolymer and lactide on the cell proliferation and the hydrophilicity of electrospun scaffolds were investigated. Based on in vitro degradation study, we found that the electrospun scaffold having PLA (40 wt%), PLGA (LA/GA=50/50, 25 wt%), PLA-b-PEG-b-PLA (20 wt%), and lactide (15 wt%) underwent a rapid weight loss of approximately 65% in 7 weeks. The hydrophobicity of this membrane, as determined by contact angle measurements in a cell buffer solution, decreased by approximately 50% from 105 degrees (of an electrospun PLA scaffold) to 50 degrees. The selection of suitable chemical compositions in conjunction with the non-invasive electrospinning process is useful in the production of a new kind of biodegradable scaffolds suitable for different biomedical applications such as cell storage and delivery as well as prevention of post-surgical adhesion because of their porosity, mechanical flexibility and tunable biodegradability.