Samuel M. Alaish

Bile salts induce resistance to apoptosis through NF-κB-mediated XIAP expression

Apoptosis plays a critical role in intestinal mucosal homeostasis. We previously showed that the bile salt taurodeoxycholate has a beneficial effect on the intestinal mucosa through an increase in resistance to apoptosis mediated by nuclear factor (NF)-&kgr;B. The current study further characterizes the effect of bile salts on intestinal epithelial cell susceptibility to apoptosis and determines if the X-linked inhibitor of apoptosis protein (XIAP) regulates bile salt-induced resistance to apoptosis. Exposure of normal intestinal epithelial cells (IEC-6) to the conjugated bile salts taurodeoxycholate (TDCA) and taurochenodeoxycholate (TCDCA) resulted in an increase in resistance to tumor necrosis factor (TNF)-&agr; and cycloheximide (CHX)-induced apoptosis, and NF-&kgr;B activation. Treatment with TDCA and TCDCA resulted in an increase in XIAP expression. Specific inhibition of NF-&kgr;B by infection with an adenoviral vector that expresses the I&kgr;B&agr; super-repressor (I&kgr;BSR) prevented the induction of XIAP expression and the bile salt-mediated resistance to apoptosis. Treatment with the specific XIAP inhibitor Smac also overcame this increase in enterocyte resistance to apoptosis. Bile salts inhibited formation of the active caspase-3 from its precursor procaspase-3. Smac prevented the inhibitory effect of bile salts on caspase-3 activation. These results indicate that bile salts increase intestinal epithelial cell resistance to apoptosis through NF-&kgr;B-mediated XIAP expression. Bile salt-induced XIAP mediates resistance to TNF-&agr;/CHX-induced apoptosis, at least partially, through inhibition of caspase-3 activity. These data support an important beneficial role of bile salts in regulation of mucosal integrity. Decreased enterocyte exposure to luminal bile salts, as occurs during starvation and parenteral nutrition, may have a detrimental effect on mucosal integrity.

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-γ mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis.

Shoshin beriberi mimicking central line sepsis in a child with short bowel syndrome

BackgroundShoshin beriberi, cardiac failure secondary to a severe deficiency of the vitamin thiamine, can develop in patients following extensive intestinal resection or bypass; however, parenteral supplementation has largely eliminated this complication. Hemodynamic instability resulting from central line sepsis is a far more common complication in these parenteral nutrition-dependent patients. This case report details the diagnosis and treatment of shoshin beriberi in a patient with short bowel syndrome whose presentation mimicked central line sepsis.MethodsA retrospective chart review was performed. Appropriate laboratory data were included.ResultsThe patient was treated unsuccessfully with antibiotics and supportive measures. Resolution of symptoms was achieved only after the empiric administration of thiamine and folate.ConclusionsThis case highlights that life-threatening thiamine deficiency mimicking septic shock can develop in patients with short bowel syndrome, despite oral multivitamin administration. We recommend diligent monitoring of vitamin levels in any total parenteral alimentation dependent patient unable to receive the intravenous multivitamin complex, regardless of oral vitamin supplementation or clinical findings.

Patch Testing for Metal Allergy With Manufacturer-Supplied Materials Before Nuss Bar Insertion.

IntroductionThe increasing use of metal implantable devices has raised awareness of nickel allergy. Preoperative patch testing for patients with pectus excavatum (PE) with a known metal allergy or history of atopy is an accepted practice before the Nuss procedure. The Nuss bar manufacturer offers a metal disc for preoperative testing for metal sensitivities. However, the efficacy of this disc is not well understood. ObjectiveThe purpose of this study was to determine the sensitivity of the metal disc in detecting nickel allergy compared with that of standard patch testing. MethodsTwo PE patients were referred for preoperative patch testing with the metal disc to screen for metal allergy before the Nuss procedure. Based on our initial findings, 7 patients without PE scheduled for patch testing for the evaluation of chronic dermatitis were additionally tested with the metal disc if they were found to have risk factors for nickel allergy. All patch testing was performed according to set standards. ConclusionsThe metal disc may not be adequately sensitive to determine nickel allergy before the Nuss procedure. Patch testing alone with standard formulations of nickel sulfate in petrolatum may be more sensitive in diagnosing nickel allergy.

Streptococcus viridans tubo-ovarian abscess in an adolescent virgin

A tubo‐ovarian abscess (TOA) is a common complication of pelvic inflammatory disease in premenopausal women; however, in virginal females, TOAs are an exceedingly rare occurrence. Within this rare subset of patients, there is almost always an underlying condition, such as vaginal voiding, or a concomitant disease process. A virginal adolescent female with no prior medical history presented with a large pelvic mass which proved to be a TOA. An exploratory laparotomy was eventually required to establish the diagnosis. Open drainage and antibiotic therapy successfully treated the patient. With only the organism, Streptococcus viridians, isolated in her cultures, an etiology of direct ascension from the lower genitourinary tract is implicated. We believe this to be the youngest case of a TOA occurring in a virginal adolescent female without a predisposing condition. A TOA should be considered in the differential diagnosis of pelvic masses in previously healthy pediatric patients regardless of their sexual activity.

Intraabdominal pulmonary sequestration presenting with elevated urinary normetanephrine levels

Carrying a prenatal diagnosis of a left-sided intraabdominal mass, a term female newborn underwent postnatal imaging that confirmed a left suprarenal mass. Urinary normetanephrine levels were elevated. Given a preoperative diagnosis of neuroblastoma, the baby underwent an uneventful resection of the mass en bloc with the left adrenal gland. The pathologic examination returned pulmonary sequestration and a normal adrenal gland. Postoperative urinary catecholamines were normal. To the best of our knowledge, this is the first description of a newborn with an intraabdominal pulmonary sequestration presenting with elevated urinary catecholamines.

Symptomatic anterior sternoclavicular joint secondary to a Bicipital rib

This case report details the diagnosis and treatment of a previously unreported complication of a congenital chest wall anomaly. Our patient presented with a painful anterior sternoclavicular joint subluxation secondary to a bicipital rib. Thoracic magnetic resonance and computed tomographic imaging provided the diagnosis. Complete resolution of symptoms was achieved after resection of the bicipital rib.

Candidate genes for limiting cholestatic intestinal injury identified by gene expression profiling

The lack of bile flow from the liver into the intestine can have devastating complications including hepatic failure, sepsis, and even death. This pathologic condition known as cholestasis can result from etiologies as diverse as total parenteral nutrition (TPN), hepatitis, and pancreatic cancer. The intestinal injury associated with cholestasis has been shown to result in decreased intestinal resistance, increased bacterial translocation, and increased endotoxemia. Anecdotal clinical evidence suggests a genetic predisposition to exaggerated injury. Recent animal research on two different strains of inbred mice demonstrating different rates of bacterial translocation with different mortality rates supports this premise. In this study, a microarray analysis of intestinal tissue following common bile duct ligation (CBDL) performed under general anesthesia on these same two strains of inbred mice was done with the goal of identifying the potential molecular mechanistic pathways responsible. Over 500 genes were increased more than 2.0‐fold following CBDL. The most promising candidate genes included major urinary proteins (MUPs), serine protease‐1‐inhibitor (Serpina1a), and lipocalin‐2 (LCN‐2). Quantitative polymerase chain reaction (qPCR) validated the microarray results for these candidate genes. In an in vitro experiment using differentiated intestinal epithelial cells, inhibition of MUP‐1 by siRNA resulted in increased intestinal epithelial cell permeability. Diverse novel mechanisms involving the growth hormone pathway, the acute phase response, and the innate immune response are thus potential avenues for limiting cholestatic intestinal injury. Changes in gene expression were at times found to be not only due to the CBDL but also due to the murine strain. Should further studies in cholestatic patients demonstrate interindividual variability similar to what we have shown in mice, then a “personalized medicine” approach to cholestatic patients may become possible.

M1703 Intestinal Permeability and Bacterial Translocation Are Modulated By the Genetic Background of the Host

G A A b st ra ct s manner with significant inhibition noted at 5.0 and 10.0 μM. 18β-GA washout restored a normal rate of cell migration. No inhibition of migration was noted between 0.625 to 2.5 μM despite reaching near complete inhibition (90-95%) of GJIC at these concentrations. The Cx-43 polypeptide exists in three isoforms under control conditions: two predominant phosphorylated forms (P2 and P1) and one minor non-phosphorylated form (P0). 18β-GA shifts the phosphorylation state of Cx-43 from nearly equal amounts of P2 and P1 to a predominantly P0 isoform at concentrations between 0.625 to 2.5 μM. Confocal microscopy revealed that Cx-43 is not present at the leading-edge lamellipodia extensions of migrating cells, but localizes primarily to the retracting edge at points of contact between cells and along lines of cortical actin filaments. Conclusions: Although a correlation exists between GJIC and Cx-43 phosphorylation state, GJIC and maintenance of the P2 isoform are not required for IEC-6 migration. Based on the specific subcellular localization of Cx-43 in migrating cells, we speculate that regulation of actin cytoskeleton dynamics may be a novel function for gap junction proteins and might regulate epithelial cell migration In Vivo along the intestinal villous. (Supported by an Intramural Research Grant for New Faculty from Michigan State University).