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Reiss JD, Peterson LS, Nesamoney SN, Chang AL, Pasca AM, Marić I, Shaw GM, Gaudilliere B, Wong RJ, Sylvester KG, Bonifacio SL, Aghaeepour N, Gibbs RS, Stevenson DK. Perinatal infection, inflammation, preterm birth, and brain injury: A review with proposals for future investigations. Exp Neurol 2022; 351:113988. [DOI: 10.1016/j.expneurol.2022.113988] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 11/26/2022]
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The consequences of chorioamnionitis: preterm birth and effects on development. J Pregnancy 2013; 2013:412831. [PMID: 23533760 PMCID: PMC3606792 DOI: 10.1155/2013/412831] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/28/2013] [Accepted: 02/10/2013] [Indexed: 11/18/2022] Open
Abstract
Preterm birth is a major cause of perinatal mortality and long-term morbidity. Chorioamnionitis is a common cause of preterm birth. Clinical chorioamnionitis, characterised by maternal fever, leukocytosis, tachycardia, uterine tenderness, and preterm rupture of membranes, is less common than subclinical/histologic chorioamnionitis, which is asymptomatic and defined by inflammation of the chorion, amnion, and placenta. Chorioamnionitis is often associated with a fetal inflammatory response. The fetal inflammatory response syndrome (FIRS) is defined by increased systemic inflammatory cytokine concentrations, funisitis, and fetal vasculitis. Clinical and epidemiological studies have demonstrated that FIRS leads to poor cardiorespiratory, neurological, and renal outcomes. These observations are further supported by experimental studies that have improved our understanding of the mechanisms responsible for these outcomes. This paper outlines clinical and experimental studies that have improved our current understanding of the mechanisms responsible for chorioamnionitis-induced preterm birth and explores the cellular and physiological mechanisms underlying poor cardiorespiratory, neural, retinal, and renal outcomes observed in preterm infants exposed to chorioamnionitis.
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Abstract
Much emphasis in recent decades has been devoted to inflammation and infection as a premier causal mechanism of preterm birth. This article explores the epidemiologic, clinical, and animal data that exist to support this conceptual paradigm as well as proposed mechanisms through which to potentially mitigate the adversity of prematurity. Truly successful interventions are not likely to occur until the pathogenesis of preterm birth and the role of inflammation in causing not only parturition but also fetal and neonatal injury is fully elucidated.
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Affiliation(s)
- Jamie A Bastek
- Maternal and Child Health Research Program, Philadelphia, PA, USA
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Kemp MW, Saito M, Newnham JP, Nitsos I, Okamura K, Kallapur SG. Preterm birth, infection, and inflammation advances from the study of animal models. Reprod Sci 2011; 17:619-28. [PMID: 20581349 DOI: 10.1177/1933719110373148] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Inflammation is a protective response mediated by both innate and adaptive arms of the immune system following exposure to a range of harmful stimuli. Although inflammation is an essential mechanism in response to challenges including tissue injury and microbiological insult, inappropriate or excessive induction of the inflammatory response is itself a well-characterized cause of morbidity and mortality in adult populations. There is currently a growing appreciation of the potential for inflammation to play an adverse role in fetal health. The expression of cytokines (notably interleukin 1beta [IL-1beta], IL-6, IL-8, and tumor necrosis factor alpha [TNF-alpha]) by either the fetal or maternal tissues has been demonstrated to upregulate the activity of a number of uterine and cervical factors (eg, prostaglandin hormones and their receptors, matrix metalloproteinases, vascular endothelial growth factor [VEGF]), leading to premature initiation of the parturition process. Herein, we review important developments in our understanding of the link between preterm birth and fetal inflammation subsequent to infection, gained from studies undertaken in animal models.
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Affiliation(s)
- Matthew W Kemp
- School of Women's and Infants' Health, The University of Western Australia, Perth, Australia.
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Animal models of ascending genital-tract infection in pregnancy. Infect Dis Obstet Gynecol 2010; 2:60-70. [PMID: 18475368 PMCID: PMC2364364 DOI: 10.1155/s1064744994000414] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/1994] [Accepted: 06/16/1994] [Indexed: 11/17/2022] Open
Abstract
This article reviews animal models currently used for investigation of ascending genital-tract infection in pregnancy. The specific models reviewed are those in the rabbit, monkey, and mouse. These models investigate both the direct effects of bacteria in the setting of ascending infection and the role of cytokines produced by the immune system. For each model, experiments that delineate the pathophysiology of ascending genital-tract infection in pregnancy are described. Intervention experiments, including the use of antibiotics, anti-inflammatory agents, immunotherapy, and anti-cytokine therapy, are described. Comparison of these models is made with respect to pathogenesis in humans, reproducibility, anatomy, and cost.
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Abstract
Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 60% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis and in a high proportion of such cases the underlying cause may be ascending infection from the lower genital tract. The causes of neonatal death in pregnancies with amniorrhexis are prematurity, pulmonary hypoplasia and sepsis. In the management of pregnancies with preterm prelabour amniorrhexis it is essential to distinguish between those with and without intrauterine infection. If there is no infection at presentation it is unlikely that this will develop and in such cases there is no benefit from hospitalisation, bed rest, prophylactic tocolytics or antibiotics. The group with evidence of intrauterine infection go into spontaneous labour within a few days of amniorrhexis; in this group the main determinant for the appropriate management is the gestation at amniorrhexis.
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Klein LL, Freitag BC, Gibbs RS, Reddy AP, Nagalla SR, Gravett MG. Detection of intra-amniotic infection in a rabbit model by proteomics-based amniotic fluid analysis. Am J Obstet Gynecol 2005; 193:1302-6. [PMID: 16202718 DOI: 10.1016/j.ajog.2005.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Revised: 04/21/2005] [Accepted: 06/01/2005] [Indexed: 11/21/2022]
Abstract
OBJECTIVE This study was undertaken to identify intra-amniotic infection caused by several different organisms in a rabbit model by using proteomics. STUDY DESIGN Twenty infected and 18 uninfected amniotic fluid samples were subjected to proteomic analysis by surface-enhanced laser desorption ionization (SELDI-TOF, Ciphergen Biosystems, Fremont, Calif), 1- and 2-dimensional gel electrophoresis, and tandem mass spectrometry (MS/MS). RESULTS Detailed SELDI-TOF spectra revealed a constitutive 4.0 kd peak in all animals. Infected samples also displayed a signature double peak at 3.6 kd. A SELDI-TOF signature profile for intra-amniotic infection predicted positive amniotic fluid and/or fetal cultures with a sensitivity of 90% and specificity of 83%. Similar proteomic profiles were obtained regardless of the infecting organism. The 3.6 kd peak appeared to contain rabbit calgranulin C and rabbit calcyclin, members of the S100 family of calcium binding proteins. CONCLUSION Amniotic fluid proteomic analysis was able to detect intra-amniotic infection in this experimental rabbit model. S100 proteins may be involved in the host inflammatory response to intra-amniotic infection.
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Affiliation(s)
- Laura L Klein
- Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver, CO, USA
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Gras-Le Guen C, Debillon T, Toquet C, Jarry A, Winer N, Jacqueline C, Kergueris MF, Bingen E, Roze JC, Potel G, Bugnon D. Persistent bacteremia in rabbit fetuses despite maternal antibiotic therapy in a novel intrauterine-infection model. Antimicrob Agents Chemother 2003; 47:2125-30. [PMID: 12821457 PMCID: PMC161868 DOI: 10.1128/aac.47.7.2125-2130.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2002] [Revised: 01/22/2003] [Accepted: 04/02/2003] [Indexed: 11/20/2022] Open
Abstract
The effect of optimized maternal therapy by bactericidal agents was evaluated in a reproducible rabbit model of Escherichia coli maternofetal infection simulating human pharmacokinetics. Intravenous antibiotic therapy was begun in the pregnant rabbit 12 h after bacterial intrauterine inoculation, using a computer-controlled pump to simulate human pharmacokinetics of ceftriaxone (1 g/day) associated or not with gentamicin (3 mg/kg of body weight/day). Data were compared for fetal survival, quantitative blood cultures, fetal histology in treated versus untreated groups, and maternal and fetal antibiotic concentrations in plasma in treated animals. Antibiotic therapy led to dramatic improvement in maternal outcome (100% survival versus 100% death in the untreated group in association with maternal septicemia). Fetal survival also improved, with the two-drug combination providing a more potent effect. After 3 days of treatment, 32% of fetuses survived with one-drug therapy and 62% with two-drug therapy (Yates corrected chi(2), P < 0.05). In untreated animals, bacterial counts in blood cultures increased rapidly during the first 24 h up to 8.1 +/- 0.5 log CFU/ml, but remained relatively constant at all times with antibiotic treatment: 4.5 +/- 0.7 log CFU/ml at the start of treatment and 6.2 +/- 0.4 and 5.2 +/- 0.9 log CFU/ml after 72 h for one- and two-drug therapy, respectively (data are means +/- standard deviations). The failure of animals to be cured after 3 days of treatment was not due to an inadequate concentration of ceftriaxone, as the residual level in fetal serum at sacrifice was more than 1000 times the MIC of the microbe. Unexpectedly, inflammation in fetal lung decreased in the treated group after as little as 24 h of antibiotic therapy, despite persistent bacteremia. Although maternal outcome improved and drug concentrations were above the MIC, the treatment did not achieve sterilization of fetuses in utero for this rabbit E. coli maternofetal infection. However, fetal survival showed some improvement, and the histologic features of lung inflammation were reduced.
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Affiliation(s)
- C Gras-Le Guen
- Laboratoire d'Antibiologie Clinique et Expérimentale, Faculté de Médecine de Nantes, Centre Hospitalier Universitaire de Nantes, Nantes, France
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Debillon T, Gras-Leguen C, Vérielle V, Caillon J, Roze JC, Gressens P. Effect of maternal antibiotic treatment on fetal periventricular white matter cell death in a rabbit intrauterine infection model. Acta Paediatr 2003; 92:81-6. [PMID: 12650305 DOI: 10.1111/j.1651-2227.2003.tb00474.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM To evaluate the effects of maternal antibiotic treatment on fetal brain cell death in a rabbit intrauterine infection model. METHODS After Escherichia coli uterine-horn inoculation in 22 pregnant rabbits, followed at various times by ceftriaxone and caesarean section, cell death in white matter (histology and fragmented DNA staining) from fetuses killed at extraction was compared across groups using the Mantel-Haenszel test and Fisher's exact test for small numbers. RESULTS White matter cell death was consistently present at 48 h, with ceftriaxone initiation at 24 h (group 1), detectable at 84 but not 60 h, with ceftriaxone initiation at 12 h, and significantly reduced at 84 h with ceftriaxone initiation at 6 h (60% vs 100% in group 1, p < 0.001, Fisher's exact test). CONCLUSION Early maternal antibiotic therapy delays white matter cell death in rabbit fetuses exposed to intrauterine infection. This may provide a window for preventing white matter damage.
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Affiliation(s)
- T Debillon
- Service de Néonatologie, Hôpital Mère-Enfant, CHRU Nantes, Nantes, France.
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Rezaie P, Dean A. Periventricular leukomalacia, inflammation and white matter lesions within the developing nervous system. Neuropathology 2002; 22:106-32. [PMID: 12416551 DOI: 10.1046/j.1440-1789.2002.00438.x] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Periventricular leukomalacia (PVL) occurring in premature infants, represents a major precursor for neurological and intellectual impairment, and cerebral palsy in later life. The disorder is characterized by multifocal areas of necrosis found deep in the cortical white matter, which are often symmetrical and occur adjacent to the lateral ventricles. There is no known cure for PVL. Factors predisposing to PVL include birth trauma, asphyxia and respiratory failure, cardiopulmonary defects, premature birth/low birthweight, associated immature cerebrovascular development and lack of appropriate autoregulation of cerebral blood flow in response to hypoxic-ischemic insults. The intrinsic vulnerability of oligodendrocyte precursors is considered as central to the pathogenesis of PVL. These cells are susceptible to a variety of injurious stimuli including free radicals and excitotoxicity induced by hypoxic-ischemic injury (resulting from cerebral hypoperfusion), lack of trophic stimuli, as well as secondary associated events involving microglial and astrocytic activation and the release of pro-inflammatory cytokines TNF-alpha and IL-6. It is yet unclear whether activated astrocytes and microglia act as principal participants in the development of PVL lesions, or whether they are representatives of an incidental pathological response directed towards repair of tissue injury in PVL. Nevertheless, the accumulated evidence points to a pathological contribution of microglia towards damage. The topography of lesions in PVL most likely reflects a combination of the relatively immature cerebrovasculature together with a failure in perfusion and/or hypoxia during the greatest period of vulnerability occurring around mid-to-late gestation. Mechanisms underlying the pathogenesis of PVL have so far been related to prenatal ischemic injury to the brain initiated within the third trimester, which result in global cognitive and developmental delay and motor disturbances. Over the past few years, several epidemiological and experimental studies have implicated intrauterine infection and chorioamnionitis as causative in the pathogenesis of PVL. In particular, recent investigations have shown that inflammatory responses in the fetus and neonate can contribute towards neonatal brain injury and development-related disabilities including cerebral palsy. This review presents current concepts on the pathogenesis of PVL and emphasizes the increasing evidence for an inflammatory pathogenic component to this disorder, either resulting from hypoxic-ischemic injury or from infection. These findings provide the basis for clinical approaches targeted at protecting the premature brain from inflammatory damage, which may prove beneficial for treating PVL, if identified early in pathogenesis.
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Affiliation(s)
- Payam Rezaie
- Department of Neuropathology, Institute of Psychiatry, King's College London, UK.
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Gibbs RS, Davies JK, McDuffie RS, Leslie KK, Sherman MP, Centretto CA, Wolf DM. Chronic intrauterine infection and inflammation in the preterm rabbit, despite antibiotic therapy. Am J Obstet Gynecol 2002; 186:234-9. [PMID: 11854641 DOI: 10.1067/mob.2002.119640] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE In a pregnant rabbit model using intracervical inoculation of Escherichia coli with delayed antibiotic therapy, we investigated the rate of positive cultures and histologic inflammation of maternal and fetal compartments and the concentration of tumor necrosis factor-alpha in the amniotic fluid for up to 5 days. STUDY DESIGN New Zealand White rabbits at 70% gestation were inoculated intracervically with 10(3) - 10(4) colony-forming units of E coli per uterine horn. At varying intervals after inoculation (0.5 - 4.0 hours), antibiotic therapy was initiated with ampicillin-sulbactam. Primary outcomes were positive cultures and histologic inflammation score. Tumor necrosis factor-alpha levels in the amniotic fluid were determined by bioassay. RESULTS A total of 60 animals were inoculated with E coli. At the endpoint, uterine cultures were positive more commonly than in the fetus or amniotic fluid (41.8% vs 27.5% vs 17.3%, respectively), which was consistent with an ascending pathway of infection. Inflammation scores were similar in uterus and placenta but lower in fetal lung and absent in fetal brain (2.8 vs 3.1 vs 0.84 vs 0.0, respectively). Comparing the durations of delay in antibiotic administration, we found a significant increase in positive uterine cultures and a significant increase in histologic inflammation score with increasing delay. The proportion of dead pups within a litter was significantly associated with the log of the tumor necrosis factor-alpha concentration in amniotic fluid and the degree of histologic inflammation in the uterus, but not with amniotic fluid or other culture positivity. CONCLUSION The administration of therapeutic doses of antibiotic does not consistently eradicate bacteria from the rabbit uterus nor, more importantly, from the fetus and the amniotic fluid. Obtaining a negative amniotic fluid culture does not exclude either infection in the decidua or the fetus or histologic inflammation with tumor necrosis factor-alpha elaboration.
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Affiliation(s)
- Ronald S Gibbs
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Denver, CO, USA
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Asrat T. Intra-amniotic infection in patients with preterm prelabor rupture of membranes. Pathophysiology, detection, and management. Clin Perinatol 2001; 28:735-51. [PMID: 11817186 DOI: 10.1016/s0095-5108(03)00074-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The recent increase in knowledge about infection and preterm delivery has engendered many new questions and should make us rethink our long held beliefs and management strategies. Although this article focused primarily on infection as an important factor in the pathogenesis of PPROM, multiple other causes do exist. The various serologic and amniotic fluid assays that can identify activation of the host immune and inflammatory responses as a consequence of the microbial invasion of the amniotic cavity detailed in the preceding paragraphs are very promising but not yet available for clinical use. These tests identify the fetus in the early stages of an infectious process, before the full clinical manifestations of chorioamnionitis. Should such fetuses be treated with antibiotics in an effort to sterilize the amniotic cavity? Should patients with documented microbial invasion be delivered immediately or is there room for a more conservative management with aggressive antibiotic in utero treatment, altering the natural course of PPROM, avoiding extremely preterm deliveries? Certainly many questions remain unanswered. Continuing the search for information on the relationship between infection and PPROM can only add hope to one day finding an option for prevention, because many and probably most cases of PPROM are apparently caused by infection, and the opportunity for preventing this problem most probably lies here.
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Affiliation(s)
- T Asrat
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of California Irvine, Orange, USA
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Tolockiene E, Morsing E, Holst E, Herbst A, Ljungh Å, Svenningsen N, Hägerstrand I, Nyström L. Intrauterine infection may be a major cause of stillbirth in Sweden. Acta Obstet Gynecol Scand 2001. [DOI: 10.1034/j.1600-0412.2001.d01-151.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tolockiene E, Morsing E, Holst E, Herbst A, Ljungh A, Svenningsen N, Hagerstrand I, Nystrom L. Intrauterine infection may be a major cause of stillbirth in Sweden. Acta Obstet Gynecol Scand 2001. [DOI: 10.1034/j.1600-0412.2001.080006511.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kenyon SL, Taylor DJ, Tarnow-Mordi W. Broad-spectrum antibiotics for spontaneous preterm labour: the ORACLE II randomised trial. ORACLE Collaborative Group. Lancet 2001; 357:989-94. [PMID: 11293641 DOI: 10.1016/s0140-6736(00)04234-3] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND Preterm birth after spontaneous preterm labour is associated with death, neonatal disease, and long-term disability. Previous small trials of antibiotics for spontaneous preterm labour have reported inconclusive results. We did a randomised multicentre trial to resolve this issue. METHODS 6295 women in spontaneous preterm labour with intact membranes and without evidence of clinical infection were randomly assigned 250 mg erythromycin (n=1611), 325 mg co-amoxiclav (250 mg amoxicillin and 125 mg clavulanic acid; n=1550), both (n=1565), or placebo (n=1569) four times daily for 10 days or until delivery, whichever occurred earlier. The primary outcome measure was a composite of neonatal death, chronic lung disease, or major cerebral abnormality on ultrasonography before discharge from hospital. Analysis was by intention to treat. FINDINGS None of the trial antibiotics was associated with a lower rate of the composite primary outcome than placebo (erythromycin 90 [5.6%], co-amoxiclav 76 [5.0%], both antibiotics 91 [5.9%], vs placebo 78 [5.0%]). However, antibiotic prescription was associated with a lower occurrence of maternal infection. INTERPRETATION This trial provides evidence that antibiotics should not be routinely prescribed for women in spontaneous preterm labour without evidence of clinical infection.
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Affiliation(s)
- S L Kenyon
- Department of Obstetrics and Gynaecology, Leicester Royal Infirmary, UK.
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Davies JK, Shikes RH, Sze CI, Leslie KK, McDuffie RS, Romero R, Gibbs RS. Histologic inflammation in the maternal and fetal compartments in a rabbit model of acute intra-amniotic infection. Am J Obstet Gynecol 2000; 183:1088-93. [PMID: 11084546 DOI: 10.1067/mob.2000.108888] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE This study was undertaken to determine the course of acute inflammation in the maternal and fetal compartments during experimentally induced ascending intra-amniotic infection. STUDY DESIGN Forty pregnant rabbits at 70% gestation were inoculated endocervically with 10(5) colony-forming units of Escherichia coli. Does were killed at 0, 4, 8, 16, 24, and 30 hours after inoculation. At necropsy, blood, peritoneal fluid, amniotic fluid, and uterine tissue were cultured. Fetal brain, lung, heart, gut, and kidney were collected for histologic examination. Necrosis, infiltrates, congestion, and edema were each assessed semiquantitatively, and mean composite histologic-inflammation scores were compared with analysis of variance. Inflammation, mitotic activity, and apoptosis were evaluated in the fetal brain, and groups were compared with analysis of variance. RESULTS Twenty-six animals were evaluated after 14 were excluded (lack of fever or positive culture results). A significant increase in histologic inflammation score was seen in the uterus (P<.001), placenta(P = .011), and fetal lung (P = .001) but not in other fetal tissues. These changes were seen earlier in the uterus and placenta and later in the fetal lung. Mitotic activity in the fetal brain decreased significantly by 8 hours after cervical inoculation. There was no inflammation in the fetal brain, and apoptosis in the fetal brain did not increase with time. CONCLUSIONS Histologic inflammation occurs early in both the uterus and the placenta and later in the fetal lung in the rabbit model of acute intra-amniotic infection. This contrasts with the previously reported chronic model of intra-amniotic infection in the rabbit.
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Affiliation(s)
- J K Davies
- Departments of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver, USA
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Debillon T, Gras-Leguen C, Vérielle V, Winer N, Caillon J, Rozé JC, Gressens P. Intrauterine infection induces programmed cell death in rabbit periventricular white matter. Pediatr Res 2000; 47:736-42. [PMID: 10832730 DOI: 10.1203/00006450-200006000-00009] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An association between chorioamnionitis and periventricular leukomalacia has been reported in human preterm infants. However, whether this link is causal has not been convincingly established, and the underlying molecular mechanisms remain unclear. The objective of this study was to establish a reproducible model of cerebral white matter disease in preterm rabbits after intrauterine infection. Escherichia coli was inoculated into both uterine horns of laparotomized pregnant rabbits when gestation was 80% complete. The fetuses were delivered by cesarean section and killed 12, 24, or 48 h after the inoculation. Programmed cell death in the white matter was evaluated by hematoxylin-eosin-saffron staining and in situ fragmented DNA labeling (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling). In a first group of 14 pregnant rabbits not treated with antibiotics, all fetuses delivered 48 h after inoculation were stillborn, whereas fetuses extracted 12 or 24 h after inoculation were alive. No significant cell death was detected in the live fetuses compared with the control noninfected rabbits. In a second group of five pregnant rabbits treated with ceftriaxone initiated 24 h after the inoculation and continued until cesarean section was performed 48 h after inoculation, 13 fetuses were alive, but all showed evidence of extensive programmed cell death in the white matter by hematoxylin-eosin-saffron staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. White matter damage became histologically detectable only 48 h after inoculation. Three of the 13 brains displayed periventricular white matter cysts mimicking human cystic periventricular leukomalacia. The high reproducibility of white matter damage in our model should permit further studies aimed at unraveling the molecular mechanisms of periventricular leukomalacia.
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Affiliation(s)
- T Debillon
- Departement de Perinatologie, Hôpital Mère-Enfant, Nantes, France
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Affiliation(s)
- S Parry
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA
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Abstract
OBJECTIVE We investigated in a pregnant rabbit model the effects of intravaginal inoculation of type la group B streptococci and antibiotic intervention. STUDY DESIGN We inoculated 10(4) to 10(6) cfu of type la group B streptococci into the upper vagina hysteroscopically at day 21 to 27 of a 31-day gestation. Initially we studied the natural history in 23 animals and then allocated the next 31 animals to receive either no therapy or ampicillin-sulbactam intramuscularly beginning immediately after inoculation. Outcomes were delivery, fever, positive cultures for group B streptococci, any live fetuses, and maternal death. RESULTS Without antibiotic treatment upper vaginal inoculation led to frequent complications, namely, fever in 44% (15/34), delivery in 41% (14/34), positive endometrial cultures in 47% (15/32), and positive blood cultures in 26% (7/27). Live fetuses were present in only 53% (18/34). Animals treated with antibiotics were significantly less likely to have fever (p < 0.01), positive endometrial cultures (p < 0.01), or positive blood cultures (p = 0.03) and were more likely to have a live fetus (p = 0.04) than untreated animals were. CONCLUSION Upper vaginal inoculation with type la group B streptococci in the rabbit led to an ascending infection of the upper genital tract, causing serious adverse outcomes in 40% with bacteremia in 26%. Early antibiotic intervention significantly improved outcomes. The susceptibility of the rabbit to ascending perinatal group B streptococci infection makes it an appealing model for further work pertinent to human disease.
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Affiliation(s)
- R S McDuffie
- Department of Obstetrics and Gynecology, Kaiser Permanente and University of Colorado School of Medicine, Denver, USA
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