A cystic fibrosis pancreatic adenocarcinoma cell line

We established a pancreatic adenocarcinoma cell line (CFPAC-1) from a patient with cystic fibrosis (CF) and assessed some of its properties. The cells show epithelial morphology and express cytokeratin and oncofetal antigens characteristic of pancreatic duct cells. Basal and stimulated levels of cAMP and cAMP-dependent protein kinase and the biophysical properties of single Cl- channels in CFPAC-1 are similar to those of airway and sweat gland primary cultures and Cl(-)-secreting epithelial cell lines. Anion transport and single Cl- channel activity was stimulated by Ca2+ ionophores but not by forskolin, cAMP analogs, or phosphodiesterase inhibitors. The cells express the CF gene and manifest the most common CF mutation, deletion of three nucleotides resulting in a phenylalanine-508 deletion. These properties have been stable through greater than 80 passages (24 months), suggesting that CFPAC-1 can serve as a continuous cell line that displays the CF defect.

Extensive tyrosine nitration in human myocardial inflammation: evidence for the presence of peroxynitrite

OBJECTIVES

Production of nitric oxide via the cytokine-mediated activation of myocardial inducible nitric oxide synthase decreases myocardial contractility. Whether myocardial dysfunction is mediated directly by nitric oxide or indirectly through the formation of secondary reaction products, such as peroxynitrite, has not been established. Peroxynitrite, but not nitric oxide, reacts with the phenolic ring of tyrosine to form the stable product 3-nitro-L-tyrosine. Demonstration of tissue nitrotyrosine residues, therefore, infers the presence of peroxynitrite or related nitrogen-centered oxidants.

DESIGN

Retrospective analysis of human autopsy specimens.

SETTING

University pathology and basic science laboratories.

PATIENTS

Formalin-fixed, paraffin-embedded myocardial tissue samples were obtained from 11 patients with a diagnosis of sepsis, seven patients with a diagnosis of viral myocarditis, and five control patients without clinical or pathologic cardiac disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Specific antibodies to nitrotyrosine were utilized to detect nitrotyrosine residues in human autopsy specimens. Cardiac tissue obtained from patients with myocarditis or sepsis demonstrated intense nitrotyrosine immunoreactivity in the endocardium, myocardium, and coronary vascular endothelium and smooth muscle. In contrast, connective tissue elements were without appreciable immunohistochemical staining. Nitrotyrosine antibody binding was blocked by coincubation with nitrotyrosine or nitrated bovine serum albumin, but not by aminotyrosine, phosphotyrosine, or bovine serum albumin. In situ reduction of tissue nitrotyrosine to aminotyrosine by sodium hydrosulfite also blocked antibody binding. Densitometric analysis of nitrotyrosine immunoreactivity demonstrated significantly higher values for specimens from myocarditis and sepsis patients when compared with control tissue specimens.

CONCLUSION

These results demonstrate the formation of peroxynitrite within the myocardium during inflammatory disease states, suggesting a role for peroxynitrite in inflammation-associated myocardial dysfunction.

TGF-β2 suppresses macrophage cytokine production and mucosal inflammatory responses in the developing intestine

BACKGROUND & AIMS

Premature neonates are predisposed to necrotizing enterocolitis (NEC), an idiopathic, inflammatory bowel necrosis. We investigated whether NEC occurs in the preterm intestine due to incomplete noninflammatory differentiation of intestinal macrophages, which increases the risk of a severe mucosal inflammatory response to bacterial products.

METHODS

We compared inflammatory properties of human/murine fetal, neonatal, and adult intestinal macrophages. To investigate gut-specific macrophage differentiation, we next treated monocyte-derived macrophages with conditioned media from explanted human fetal and adult intestinal tissues. Transforming growth factor-β (TGF-β) expression and bioactivity were measured in fetal/adult intestine and in NEC. Finally, we used wild-type and transgenic mice to investigate the effects of deficient TGF-β signaling on NEC-like inflammatory mucosal injury.

RESULTS

Intestinal macrophages in the human preterm intestine (fetus/premature neonate), but not in full-term neonates and adults, expressed inflammatory cytokines. Macrophage cytokine production was suppressed in the developing intestine by TGF-β, particularly the TGF-β(2) isoform. NEC was associated with decreased tissue expression of TGF-β(2) and decreased TGF-β bioactivity. In mice, disruption of TGF-β signaling worsened NEC-like inflammatory mucosal injury, whereas enteral supplementation with recombinant TGF-β(2) was protective.

CONCLUSIONS

Intestinal macrophages progressively acquire a noninflammatory profile during gestational development. TGF-β, particularly the TGF-β(2) isoform, suppresses macrophage inflammatory responses in the developing intestine and protects against inflammatory mucosal injury. Enterally administered TGF-β(2) protected mice from experimental NEC-like injury.

Plasma concentrations of inflammatory cytokines rise rapidly during ECMO-related SIRS due to the release of preformed stores in the intestine

Extracorporeal membrane oxygenation (ECMO) is a life-saving support system used in neonates and young children with severe cardiorespiratory failure. Although ECMO has reduced mortality in these critically ill patients, almost all patients treated with ECMO develop a systemic inflammatory response syndrome (SIRS) characterized by a 'cytokine storm', leukocyte activation, and multisystem organ dysfunction. We used a neonatal porcine model of ECMO to investigate whether rising plasma concentrations of inflammatory cytokines during ECMO reflect de novo synthesis of these mediators in inflamed tissues, and therefore, can be used to assess the severity of ECMO-related SIRS. Previously healthy piglets (3-week-old) were subjected to venoarterial ECMO for up to 8 h. SIRS was assessed by histopathological analysis, measurement of neutrophil activation (flow cytometry), plasma cytokine concentrations (enzyme immunoassays), and tissue expression of inflammatory genes (PCR/western blots). Mast cell degranulation was investigated by measurement of plasma tryptase activity. Porcine neonatal ECMO was associated with systemic inflammatory changes similar to those seen in human neonates. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) concentrations rose rapidly during the first 2 h of ECMO, faster than the tissue expression of these cytokines. ECMO was associated with increased plasma mast cell tryptase activity, indicating that increased plasma concentrations of inflammatory cytokines during ECMO may result from mast cell degranulation and associated release of preformed cytokines stored in mast cells. TNF-alpha and IL-8 concentrations rose faster in plasma than in the peripheral tissues during ECMO, indicating that rising plasma levels of these cytokines immediately after the initiation of ECMO may not reflect increasing tissue synthesis of these cytokines. Mobilization of preformed cellular stores of inflammatory cytokines such as in mucosal mast cells may have an important pathophysiological role in ECMO-related SIRS.

A new genetic disorder in mitochondrial fatty acid beta-oxidation: ACAD9 deficiency

The acyl-CoA dehydrogenases are a family of multimeric flavoenzymes that catalyze the alpha,beta -dehydrogenation of acyl-CoA esters in fatty acid beta -oxidation and amino acid catabolism. Genetic defects have been identified in most of the acyl-CoA dehydrogenases in humans. Acyl-CoA dehydrogenase 9 (ACAD9) is a recently identified acyl-CoA dehydrogenase that demonstrates maximum activity with unsaturated long-chain acyl-CoAs. We now report three cases of ACAD9 deficiency. Patient 1 was a 14-year-old, previously healthy boy who died of a Reye-like episode and cerebellar stroke triggered by a mild viral illness and ingestion of aspirin. Patient 2 was a 10-year-old girl who first presented at age 4 mo with recurrent episodes of acute liver dysfunction and hypoglycemia, with otherwise minor illnesses. Patient 3 was a 4.5-year-old girl who died of cardiomyopathy and whose sibling also died of cardiomyopathy at age 21 mo. Mild chronic neurologic dysfunction was reported in all three patients. Defects in ACAD9 mRNA were identified in the first two patients, and all patients manifested marked defects in ACAD9 protein. Despite a significant overlap of substrate specificity, it appears that ACAD9 and very-long-chain acyl-CoA dehydrogenase are unable to compensate for each other in patients with either deficiency. Studies of the tissue distribution and gene regulation of ACAD9 and very-long-chain acyl-CoA dehydrogenase identify the presence of two independently regulated functional pathways for long-chain fat metabolism, indicating that these two enzymes are likely to be involved in different physiological functions.

FGF-10 is decreased in bronchopulmonary dysplasia and suppressed by Toll-like receptor activation

Many extremely preterm infants continue to suffer from bronchopulmonary dysplasia, which results from abnormal saccular-stage lung development. Here, we show that fibroblast growth factor-10 (FGF-10) is required for saccular lung development and reduced in the lung tissue of infants with bronchopulmonary dysplasia. Although exposure to bacteria increases the risk of bronchopulmonary dysplasia, no molecular target has been identified connecting inflammatory stimuli and abnormal lung development. In an experimental mouse model of saccular lung development, activation of Toll-like receptor 2 (TLR2) or Toll-like receptor 4 (TLR4) inhibited FGF-10 expression, leading to abnormal saccular airway morphogenesis. In addition, Toll-mediated FGF-10 inhibition disrupted the normal positioning of myofibroblasts around saccular airways, similar to the mislocalization of myofibroblasts seen in patients with bronchopulmonary dysplasia. Reduced FGF-10 expression may therefore link the innate immune system and impaired lung development in bronchopulmonary dysplasia.

Oligopeptides as catalysts for asymmetric epoxidation

Oligopeptides are versatile catalysts for the enantioselective epoxidation of electron deficient alkenes, (e.g. alpha,beta-unsaturated ketones) with alkaline hydrogen peroxide. This review describes optimisation of the catalyst, substrate range, synthetic applications of the products and rationalisation of the stereoselectivity by an active site model.

Desmin positivity in primitive neuroectodermal tumors of childhood

In this report, we describe two rosette-forming primitive neuroectodermal tumors that were found to contain desmin by both immunohistochemistry and Western blotting. Electron microscopy on both cases was consistent with primitive neuroectodermal tumors and revealed that the tumor cells contained cytoplasmic bundles of intermediate filaments. In both cases, studies for MyoD1 protein using immunohistochemistry and Western blotting were negative. Thus, the detection of desmin in a pediatric neoplasm does not absolutely exclude the diagnosis of primitive neuroectodermal tumor and should not be considered as prima facie evidence that a small-cell tumor is a rhabdomyosarcoma.

Evidence for in vivo peroxynitrite production in human acute lung injury

Oxidant-mediated toxicity resulting from acute pulmonary inflammation has been demonstrated in acute lung injury. A potent biological oxidant, peroxynitrite, is formed by the near diffusion-limited reaction of nitric oxide with superoxide. In addition to having hydroxyl radical-like oxidative reactivity, peroxynitrite is capable of nitrating phenolic rings, including protein-associated tyrosine residues. Nitric oxide does not directly nitrate tyrosine residues, therefore, demonstration of tissue nitrotyrosine residues infers the action of peroxynitrite or related nitrogen-centered oxidants. Lung tissue was obtained from formalin-fixed, paraffin-embedded autopsy specimens, and specific polyclonal and monoclonal antibodies to nitrotyrosine were visualized by diaminobenzidene-peroxidase staining. Acute lung injury resulted in intense staining throughout the lung, including lung interstitium, alveolar epithelium, proteinaceous alveolar exudate, and inflammatory cells. In addition, staining of the vascular endothelium and subendothelial tissues was present in those patients with sepsis-induced acute lung injury. Antibody binding was blocked by coincubation with nitrotyrosine or nitrated bovine serum albumin but not by aminotyrosine, phosphotyrosine, or bovine serum albumin. Reduction of tissue nitrotyrosine to aminotyrosine by sodium hydrosulfite also blocked antibody binding. In control specimens with no overt pulmonary disease, there was only slight staining of the alveolar septum. These results demonstrate that nitrogen-derived oxidants are formed in human acute lung injury and suggest that peroxynitrite may be an important oxidant in inflammatory lung disease.

Partial liquid breathing with perflubron improves arterial oxygenation in acute canine lung injury

Tidal liquid breathing with perfluorocarbon liquid improves lung mechanics and gas exchange in surfactant-deficient lambs. We asked whether an intratracheal dose of perflubron equal to liquid functional residual capacity (FRC) or less (partial liquid breathing) would alter gas exchange in gas-ventilated, anesthetized, and oleic acid (OA)-injured dogs. We gave eight dogs perflubron in six aliquots, each equal to one-sixth of liquid FRC [sequential dose (SEQ) group], starting 90 min after OA. Two other groups of eight dogs each received a liquid FRC dose of perflubron (60-70 ml/kg) either just before (P-Pre) or 90 min after (P-Post) OA, and eight control (CON) dogs received OA but no perflubron. In CON, SEQ, and P-Post dogs, OA caused a significant decrease in static respiratory system compliance (Crs) (1.50 +/- 0.05 to 1.15 +/- 0.06 ml.cmH2O-1.kg-1) and arterial PO2 (508 +/- 10 to 113 +/- 16 Torr) by minute 90. In P-Pre, P-Post, and after the third dose of perflubron (50% FRC) in SEQ dogs, arterial PO2 was significantly higher than that in the CON dogs but was similar to that in the CON dogs after perflubron removal. Perflubron doses less than two-thirds of liquid FRC were associated with increased Crs compared with CON dogs, but further lung filling caused a decrease in Crs. Lung histology showed widespread edema and hemorrhage and was similar in perflubron and CON dogs. O2 delivery and uptake were well maintained in all four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytomegalovirus glomerulopathy: a controversial lesion

Seven autopsies performed on immunosuppressed bone marrow transplant recipients who died with documented herpes virus infection were reviewed. The kidneys were studied by light and electron microscopy and revealed no pathological findings, specifically no glomerulopathy or tubular interstitial nephritis. Seven renal biopsies performed on kidney transplant recipients in whom a diagnosis of cytomegalovirus glomerulopathy was entertained were also studied. These patients exhibited clinical parameters suggestive of cytomegalovirus infection. Three patients had subsequent nephrectomies and two showed severe acute vascular rejection. The one kidney without demonstrable acute vascular rejection was negative for cytomegalovirus on culture. Three additional patients improved or stabilized their renal function under therapy for rejection. Light, electron microscopic and immunofluorescent studies, although confirmatory of endothelial cell damage, did not substantiate active cytomegalovirus renal infection in these patients. An additional group of fifteen children with disseminated cytomegalovirus infection revealed no evidence of glomerulopathy. Finally, two kidney transplant recipients with proven cytomegalovirus infection (one with associated tubular interstitial nephritis) also showed no glomerular alterations. It is the author's opinion that the entity that has been considered as cytomegalovirus glomerulopathy probably represents rejection, either a peculiar anti-endothelial type of rejection or a protracted, early, or partially resolved acute vascular rejection without residual or identifiable acute vascular rejection changes in the tissue sampled.

Older age at diagnosis of Hirschsprung disease decreases risk of postoperative enterocolitis, but resection of additional ganglionated bowel does not

PURPOSE

This study was conducted to determine the effect of age at diagnosis and length of ganglionated bowel resected on postoperative Hirschsprung-associated enterocolitis (HAEC).

METHODS

Children who underwent endorectal pull-through (ERPT) between January 1993 and December 2004 were retrospectively reviewed. t Test, analysis of variance, Kaplan-Meier, and Cox's proportional hazards analyses were performed.

RESULTS

Fifty-two children with Hirschsprung disease (median age, 25 days; range, 2 days-16 years) were included. Nineteen (37%) had admissions for HAEC. Proportional hazards regression showed that HAEC admissions decreased by 30% with each doubling of age at diagnosis (P = .03) and increased 9-fold when postoperative stricture was present (P < .01), after controlling for type of ERPT, trisomy 21, transition zone level, and preoperative enterocolitis. Thirty-six children, with age at initial operation less than 6 months, were grouped based on length of ganglionated bowel excised (A [5 cm] and B [>5 cm]). No significant difference in the number of HAEC admissions during initial 2 years post-ERPT was seen between groups A (n = 18) and B (n = 18). The study had a power of 0.8 to detect a difference of 1 admission over 2 years.

CONCLUSIONS

Children diagnosed with Hirschsprung disease at younger ages are at a greater risk for postoperative enterocolitis. Excising a longer margin of ganglionated bowel (>5 cm) does not seem to be beneficial in decreasing HAEC admissions.

Analysis of disability resulting from treatment including radical neck dissection or modified neck dissection

A multiinstitutional study to define the impact of total treatment programs involving radical neck dissection (RND) and modified neck dissection (MND) on patients' permanent disability was undertaken. A total of 243 patient responses were included in the study. Comparative analyses between the treatment groups show no advantage of one surgical operation over the other in returning patients to their pretreatment employment status. Radiation therapy was identified as adding significantly to the patient's permanent disability.

Myofibroblast differentiation and enhanced TGF-B signaling in cystic fibrosis lung disease

Rationale

TGF-β, a mediator of pulmonary fibrosis, is a genetic modifier of CF respiratory deterioration. The mechanistic relationship between TGF-β signaling and CF lung disease has not been determined.

Objective

To investigate myofibroblast differentiation in CF lung tissue as a novel pathway by which TGF-β signaling may contribute to pulmonary decline, airway remodeling and tissue fibrosis.

Methods

Lung samples from CF and non-CF subjects were analyzed morphometrically for total TGF-β₁, TGF-β signaling (Smad2 phosphorylation), myofibroblast differentiation (α-smooth muscle actin), and collagen deposition (Masson trichrome stain).

Results

TGF-β signaling and fibrosis are markedly increased in CF (p<0.01), and the presence of myofibroblasts is four-fold higher in CF vs. normal lung tissue (p<0.005). In lung tissue with prominent TGF-β signaling, both myofibroblast differentiation and tissue fibrosis are significantly augmented (p<0.005).

Conclusions

These studies establish for the first time that a pathogenic mechanism described previously in pulmonary fibrosis is also prominent in cystic fibrosis lung disease. The presence of TGF-β dependent signaling in areas of prominent myofibroblast proliferation and fibrosis in CF suggests that strategies under development for other pro-fibrotic lung conditions may also be evaluated for use in CF.

The tectorial membrane: Anatomical, biomechanical, and histological analysis

There is minimal information in the literature regarding the tectorial membrane. Further, information in the literature regarding the anatomy and function of this structure is often contradictory. We performed the current study to elucidate further this structure's detailed anatomy, function, and histology. Thirteen adult cadavers underwent dissection of their tectorial membranes and detailed observations and measurements were made of them. Ranges of motion of the craniocervical junction were performed before and after transection of this structure. Histological analysis was performed on all membranes. The tectorial membrane was found to attach much more superiorly than previously described and was found to be firmly adherent to the cranial base and body of the axis but not to the posterior aspect of the odontoid process. The mean thickness of this membrane was found to be 1 mm. Flexion of the head made the tectorial membrane fully taut at 15 degrees and extension made it fully taut at 20 degrees; however, there was a buckling effect (redundant tectorial membrane) noted at the level of the odontoid process in extension. With the alar and transverse ligaments cut and with flexion of the head, the middle portion of this membrane was stretched over the odontoid process, thus acting as a "hammock" that inhibited the odontoid process from moving posteriorly. The tectorial membrane did not limit cervical flexion per se but rather helped to insure that the odontoid process did not impinge into the cervical canal. Lateral flexion was not found to be limited by this structure. Histologically, parallel collagen fibers with spindle-shaped fibrocytes were observed within this membrane and near its attachment to the posterior axis, the collagen fibers were noted to be more homogenous with larger non-spindled fibrocytes. At the cranial attachment of the tectorial membrane, multiple calcified areas were noted that interdigitated with the underlying bone. Also near this cephalic bony attachment, there was an increase in the number of elastic fibers, which were found running parallel with the surrounding Type III collagen fibers. The tectorial membrane was found to attach much more superiorly than previously described. We would propose that the tectorial membrane provides for a second line of defense, preventing the odontoid process from compressing the spinal cord and by doing so, secondarily limits movement of the craniocervical juncture. This hypothesis is strengthened by the finding of many elastic fibers in the tectorial membrane. To our knowledge, our study is the first to perform a detailed histological analysis of the tectorial membrane. We hope that these data are useful to the clinician who investigates this ligament of the craniocervical region.

Regulation of alveolar septation by microRNA-489

MicroRNAs (miRs) are small conserved RNA that regulate gene expression. Bioinformatic analysis of miRNA profiles during mouse lung development indicated a role for multiple miRNA, including miRNA-489. miR-489 increased on completion of alveolar septation [postnatal day 42 (P42)], associated with decreases in its conserved target genes insulin-like growth factor-1 (Igf1) and tenascin C (Tnc). We hypothesized that dysregulation of miR-489 and its target genes Igf1 and Tnc contribute to hyperoxia-induced abnormal lung development. C57BL/6 mice were exposed to normoxia (21%) or hyperoxia (85% O2) from P4 to P14, in combination with intranasal locked nucleic acid against miR-489 to inhibit miR-489, cytomegalovirus promoter (pCMV)-miR-489 to overexpress miR-489, or empty vector. Hyperoxia reduced miR-489 and increased Igf1 and Tnc. Locked nucleic acid against miR-489 improved lung development during hyperoxia and did not alter it during normoxia, whereas miR-489 overexpression inhibited lung development during normoxia. The 3' untranslated region in vitro reporter studies confirmed Igf1 and Tnc as targets of miR-489. While miR-489 was of epithelial origin and present in exosomes, its targets Igf1 and Tnc were produced by fibroblasts. Infants with bronchopulmonary dysplasia (BPD) had reduced lung miR-489 and increased Igf1 and Tnc compared with normal preterm or term infants. These results suggest increased miR-489 is an inhibitor of alveolar septation. During hyperoxia or BPD, reduced miR-489 and increased Igf1 and Tnc may be inadequate attempts at compensation. Further inhibition of miR-489 may permit alveolar septation to proceed. The use of specific miRNA antagonists or agonists may be a therapeutic strategy for inhibited alveolarization, such as in BPD.

The mechanism of polyleucine catalysed asymmetric epoxidation

Catalysis in the Julia-Colonna epoxidation of alpha,beta-unsaturated ketones is due to binding of the hydroperoxide enolate intermediate by the three N-terminal amidic N-H groups of alpha-helical poly-leucine; the N-terminal pair forms an oxy-anion hole, whilst the third aids displacement of hydroxide.

Treatment of IgA nephropathy in children: efficacy of alternate-day oral prednisone

We have previously reported our experience with the use of alternate-day prednisone in the treatment of 6 patients with IgA nephropathy who have clinical or pathological risk factors for disease progression. We have now treated a total of 13 patients and followed them from 4 to 10 years. Patients received an alternate-morning dose of prednisone for 2-4 years. Dosage began at 60 mg/m2 for 3 month, was reduced to 30 mg/m2 by 1 year and 15 mg/m2 by 2 years. At last observation, urinary protein excretion was normal in 12 patients and no patient had hematuria. Twelve patients had normal estimated glomerular filtration rate (GFR) and one had renal insufficiency (GFR = 38 ml/min per 1.73 m2). A renal biopsy was performed in 11 patients after 2 years of treatment. Activity score decreased from 5.2 to 4.3 (P = 0.03) and chronicity score increased from 2.2 to 2.8 (P = 0.12). There were no complications of treatment. When compared with a historical group, the treated patients had a significant improvement in urinalysis (P < 0.00001) and preservation of normal GFR (P = 0.03). We conclude that alternate-day prednisone therapy may benefit patients with IgA nephropathy. A large prospective controlled trial is needed.

Subclinical inflammation phenotypes and long-term outcomes after pediatric kidney transplantation

The implementation of surveillance biopsies in pediatric kidney transplantation remains controversial. Surveillance biopsies detect subclinical injury prior to clinical dysfunction, which could allow for early interventions that prolong allograft survival. We conducted a single-center retrospective cohort study of 120 consecutive pediatric kidney recipients, of whom 103 had surveillance biopsies ≤6 months posttransplant. We tested the hypothesis that subclinical inflammation (borderline or T cell-mediated rejection without clinical dysfunction) is associated with a 5-year composite endpoint of acute rejection and allograft failure. Overall, 36% of subjects had subclinical inflammation, which was associated with increased hazard for the composite endpoint (adjusted hazard ratio 2.89 [1.27, 6.57]; P < .01). Subjects with treated vs untreated subclinical borderline rejection had a lower incidence of the composite endpoint (41% vs 67%; P < .001). Subclinical vascular injury (subclinical inflammation with Banff arteritis score > 0) had a 78% incidence of the composite endpoint vs 11% in subjects with no major surveillance abnormalities (P < .001). In summary, we showed that subclinical inflammation phenotypes were prevalent in pediatric kidney recipients without clinical dysfunction and were associated with increased acute rejection and allograft failure. Once prospectively validated, our data would support implementation of surveillance biopsies as standard of care in pediatric kidney transplantation.

Gastrin-releasing peptide is a growth factor for human neuroblastomas

OBJECTIVE

To evaluate whether gastrin-releasing peptide (GRP) and GRP receptor (GRP-R) expression correlate with tumor behavior and to examine the mitogenic actions of GRP on neuroblastomas.

SUMMARY BACKGROUND DATA

Neuroblastoma is the most common solid tumor of infants and children. Despite recent advances in multimodality treatment regimens, the survival for advanced-stage tumors remains dismal. Neuroblastomas are known to produce GRP; however, the proliferative effects of GRP on neuroblastomas have not been elucidated.

METHODS

Sections of paraffin-embedded neuroblastomas from 33 patients were analyzed for GRP and GRP-R protein expression by immunohistochemistry. Functional binding of GRP-R to the Ca2+ signaling pathway was examined. In addition, the proliferative effect of GRP on neuroblastoma cells (SK-N-SH, IMR-32, SH-SY5Y, LAN-1) was determined.

RESULTS

Immunohistochemical analysis showed GRP and GRP-R protein expression in neuroblastomas; an increased expression of GRP-R was noted in a higher percentage of undifferentiated tumors compared with tumors that were benign. GRP-R mRNA was confirmed in neuroblastoma cell lines. GRP treatment resulted in intracellular calcium [Ca2+]i mobilization in two cell lines (SK-N-SH, LAN-1). GRP treatment stimulated growth of all four neuroblastoma cell lines; this effect was inhibited in SK-N-SH cells by pretreatment with GRP antibody.

CONCLUSIONS

These findings show increased GRP-R expression in the more aggressive and undifferentiated neuroblastomas. The synchronous expression of GRP and its receptor, GRP-R, suggests a role for these proteins in tumor growth. Moreover, these findings show enhanced proliferation of neuroblastoma cells in vitro after GRP treatment, suggesting that GRP may act as an autocrine and/or paracrine growth factor for neuroblastomas. Treatment with specific GRP-R antagonists may provide novel adjuvant therapy for neuroblastomas in children.

Epithelial cells in fetal intestine produce chemerin to recruit macrophages

Macrophages are first seen in the fetal intestine at 11-12 wk and rapidly increase in number during the 12- to 22-wk period of gestation. The development of macrophage populations in the fetal intestine precedes the appearance of lymphocytes and neutrophils and does not require the presence of dietary or microbial antigens. In this study, we investigated the role of chemerin, a recently discovered, relatively selective chemoattractant for macrophages, in the recruitment of macrophage precursors to the fetal intestine. Chemerin mRNA/protein expression was measured in jejunoileal tissue from 10- to 24-wk human fetuses, neonates operated for intestinal obstruction, and adults undergoing bariatric surgery. The expression of chemerin in intestinal epithelial cells (IECs) was confirmed by using cultured primary IECs and IEC-like cell lines in vitro. The regulatory mechanisms involved in chemerin expression were investigated by in silico and immunolocalization techniques. IECs in the fetal, but not mature, intestine express chemerin. Chemerin expression peaked in the fetal intestine at 20-24 wk and then decreased to original low levels by full term. During the 10- to 24-wk period, chemerin accounted for most of the macrophage chemotactic activity of cultured fetal IECs. The maturational changes in chemerin expression correlated with the expression of retinoic acid receptor-beta in the intestine. Chemerin is an important mediator of epithelial-macrophage cross talk in the fetal/premature, but not in the mature, intestine. Understanding the regulation of the gut macrophage pool is an important step in development of novel strategies to boost mucosal immunity in premature infants and other patient populations at risk of microbial translocation.

Gastrointestinal autonomic nerve tumors in the pediatric population: a report of four cases and a review of the literature

BACKGROUND

Gastrointestinal autonomic nerve tumors (GANTs) are a subpopulation of gastrointestinal stromal tumors (GISTs) that are characterized by ultrastructural features resembling enteric autonomic nerve cells, without epithelial, Schwannian, or smooth muscle differentiation. Delineation of the clinicopathologic features of GANT in the pediatric population is lacking.

METHODS

The clinicopathologic and outcome data for four pediatric patients with GANT are presented. The data from these patients and four previously reported pediatric patients are summarized and compared with data for GANT in adults.

RESULTS

All four cases occurred in females at a mean age of 12.5 years. The primary tumor site was the stomach in all cases, and the mean tumor size was 6.3 cm. Immunocytochemical and ultrastructural examination were essential in distinguishing GANT from GIST in all cases by identifying features of neural origin (neuron specific enolase in all four cases, NFP in three cases, S-100 in two cases, dense core neurosecretory granules in all four cases, and neuritelike processes in all four cases), while failing to identify features of myogenic origin (no desmin, smooth muscle actin, myofilaments, or dense bodies were found in any of the cases). Primary treatment was surgical, with chemotherapy administered to 1 patient at the time of recurrence. All patients are alive after a mean follow-up of 60 months (range, 8 months to 9 years).

CONCLUSIONS

Similarities of pediatric GANT to GANT in adults include the need for a high index of suspicion for diagnosis; comparable histopathologic, immunohistochemical, and ultrastructural features; and surgery as the primary therapy. Distinguishing features in children may be a prevalence among females in the second decade, a predominance of smaller gastric tumors, and a positive prognostic value of younger age.

Molecular mechanisms contributing to necrotizing enterocolitis

OBJECTIVE

To examine the cellular mechanisms involved in the pathogenesis of necrotizing enterocolitis (NEC).

SUMMARY BACKGROUND DATA

Necrotizing enterocolitis is a major cause of death and complications in neonates; the cellular mechanisms responsible for NEC are unknown. The inducible form of cyclooxygenase (i.e., COX-2) is activated by the transcription factor nuclear factor (NF)-kappaB and is thought to play a role in inflammation.

METHODS

Segments of perforated and adjacent uninvolved small intestine from neonates with NEC were analyzed for COX-2 expression by immunohistochemistry. NEC was induced in weanling (18 days old) rats by occlusion of superior mesenteric vessels for 1 hour and intraluminal injection of platelet activating factor (50 micro/kg). Small intestine was harvested for protein extraction. Western immunoblot was performed to determine expression of COX-2. Gel shift assays were performed to assess NF-kappaB binding activity.

RESULTS

Immunohistochemical analysis showed increased COX-2 protein expression in the perforated intestinal sections of all 36 neonates but not in adjacent normal intestine. Increased expression of COX-2 protein and NF-kappaB binding activity was noted in the small intestine of weanling rats at 0 and 3 hours after induction of NEC.

CONCLUSIONS

Increased COX-2 expression was identified in all neonatal intestinal segments resected for perforated NEC. In addition, a coordinate induction of COX-2 expression and NF-kappaB binding was noted in a rodent model of NEC. These findings suggest that the COX-2/NF-kappaB pathway may play a role in the pathogenesis of NEC. Therapeutic agents that target this pathway may prove useful in the treatment or possible prevention of NEC.