Enteric serotonin and oxytocin: endogenous regulation of severity in a murine model of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC), a gastrointestinal inflammatory disease of unknown etiology that may also affect the liver, causes a great deal of morbidity and mortality in premature infants. We tested the hypothesis that signaling molecules, which are endogenous to the bowel, regulate the severity of intestinal and hepatic damage in an established murine NEC model. Specifically, we postulated that mucosal serotonin (5-HT), which is proinflammatory, would exacerbate experimental NEC and that oxytocin (OT), which is present in enteric neurons and is anti-inflammatory, would oppose it. Genetic deletion of the 5-HT transporter (SERT), which increases and prolongs effects of 5-HT, was found to increase the severity of systemic manifestations, intestinal inflammation, and associated hepatotoxicity of experimental NEC. In contrast, genetic deletion of tryptophan hydroxylase 1 (TPH1), which is responsible for 5-HT biosynthesis in enterochromaffin (EC) cells of the intestinal mucosa, and TPH inhibition with LP-920540 both decrease the severity of experimental NEC in the small intestine and liver. These observations suggest that 5-HT from EC cells helps to drive the inflammatory damage to the gut and liver that occurs in the murine NEC model. Administration of OT decreased, while the OT receptor antagonist atosiban exacerbated, the intestinal inflammation of experimental NEC. Data from the current investigation are consistent with the tested hypotheses-that the enteric signaling molecules, 5-HT (positively) and OT (negatively) regulate severity of inflammation in a mouse model of NEC. Moreover, we suggest that mucosally restricted inhibition of 5-HT biosynthesis and/or administration of OT may be useful in the treatment of NEC.NEW & NOTEWORTHY Serotonin (5-HT) and oxytocin reciprocally regulate the severity of intestinal inflammation and hepatotoxicity in a murine model of necrotizing enterocolitis (NEC). Selective depletion of mucosal 5-HT through genetic deletion or inhibition of tryptophan hydroxylase-1 ameliorates, while deletion of the 5-HT uptake transporter, which increases 5-HT availability, exacerbates the severity of NEC. In contrast, oxytocin reduces, while the oxytocin receptor antagonist atosiban enhances, NEC severity. Peripheral tryptophan hydroxylase inhibition may be useful in treatment of NEC.

Failure of a repeat course of cyclooxygenase inhibitor to close a PDA is a risk factor for developing chronic lung disease in ELBW infants.

BACKGROUND: The optimal treatment regimen or protocol for managing a persistent patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants has not been well established. This study was aimed at evaluating the failure rate of a cyclooxygenase (COX) inhibitor (COI) for PDA closure and to determine the incidence of a PDA requiring ligation in ELBW infants. We examined the clinical characteristics and risk factors that may predict the clinical consequences of failure of PDA closure by COI. METHODS: Medical information on 138 infants with birth weight (BW) < 1000 gm who survived for > 48 hours was retrieved. Clinical characteristics and outcomes of patients whose PDAs closed with COI were compared with those who did not close. RESULTS: Of the 138 patients, 112 survived to discharge. Eighty (71.4%) of those who survived received 1-3 courses of COI treatment for a symptomatic PDA. A total of 32 (40%) failed COI treatment and underwent PDA ligation. Multivariable logistic regression analysis suggests that the observed differences in the outcomes in infants with or without symptomatic PDA can be explained by the babies with symptomatic PDA being more immature and sicker. No significant difference was seen in the incidence of chronic lung disease (CLD) in infants whose PDA was treated medically versus those who failed medical treatment and then underwent ligation. However, after adjusting for disease severity and other known risk factors, the odds ratio of developing CLD for surviving babies with a persistent PDA compared to those whose PDA was successfully closed with 1-2 courses of COI is 3.24 (1.07-9.81; p = 0.038). CONCLUSIONS: When successfully treated, PDA in ELBW infants did not contribute significantly to the adverse outcomes such as CLD, retinopathy of prematurity (ROP) and age at discharge. This suggests that it is beneficial for a hemodynamically significant PDA to be closed. The failure of a repeat course of COI to close a PDA is a major risk factor for developing CLD in ELBW infants.

Vaginal speculum lubrication and its effects on cervical cytology and microbiology.

The prevailing approach to Papanicolaou (Pap) and endocervical Gen-Probe(R) screening is to use an unlubricated vaginal speculum because of concerns that gel lubricant interferes with Pap smear adequacy and cervical microbiology. This study tests the hypothesis that lubrication of metal specula with a bacteriostatic gel does not increase unsatisfactory cervical cytology or decrease detection rates of endocervical Chlamydia trachomatis or Neisseria gonorrhoeae. At a publicly funded family planning clinic site, each of eight consecutive months was randomly designated by computer as an exclusively gel-lubricated or water-moistened specula use month. The assigned vaginal speculum intervention was used on all patients receiving a Pap smear and/or combination DNA probe assay for endocervical C. trachomatis and N. gonorrhoeae. From July 2003 through February 2004, 3460 Pap smears and 5535 combination probe assays for C. trachomatis and N. gonorrhoeae were collected from 6538 patients. During the 4 months of gel lubricant use, the rate of unsatisfactory cytology was 1.1% compared to 1.5% during the 4 months of water lubrication [odds ratio (OR) 0.74; 95% confidence interval (CI) 0.41-1.35]. During the 4 months of gel lubricant use, the detection rate for endocervical C. trachomatis was 1.5% compared to 1.5% (OR 1.05; 95% CI 0.67-1.62) in water lubricant months. The study population N. gonorrhoeae infection rate was too low to statistically analyze. The use of a small amount of gel lubricant on metal vaginal specula did not increase unsatisfactory cytology or decrease endocervical C. trachomatis detection rates when compared to water lubricant.

The presenilin-1 familial Alzheimer disease mutant P117L impairs neurogenesis in the hippocampus of adult mice.

The functions of presenilin 1 (PS1) and how PS1 mutations cause familial Alzheimer's disease (FAD) are incompletely understood. PS1 expression is essential for neurogenesis during embryonic development and may also influence neurogenesis in adult brain. We examined how increasing PS1 expression or expressing an FAD mutant would affect neurogenesis in the adult hippocampus. A neuron-specific enolase (NSE) promoter was used to drive neuronal overexpression of either wild-type human PS1 or the FAD mutant P117L in transgenic mice, and the animals were studied under standard-housing conditions or after environmental enrichment. As judged by bromodeoxyuridine (BrdU) labeling, neural progenitor proliferation rate was mostly unaffected by increasing expression of either wild-type or FAD mutant PS1. However, in both housing conditions, the FAD mutant impaired the survival of BrdU-labeled neural progenitor cells leading to fewer new beta-III-tubulin-immunoreactive neurons being generated in FAD mutant animals during the 4-week postlabeling period. The effect was FAD mutant specific in that neural progenitor survival and differentiation in mice overexpressing wild-type human PS1 were similar to nontransgenic controls. Two additional lines of PS1 wild-type and FAD mutant transgenic mice showed similar changes indicating that the effects were not integration site-dependent. These studies demonstrate that a PS1 FAD mutant impairs new neuron production in adult hippocampus by decreasing neural progenitor survival. They also identify a new mechanism whereby PS1 FAD mutants may impair normal neuronal function and may have implications for the physiological functioning of the hippocampus in FAD.